/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1999 Poul-Henning Kamp.
 * Copyright (c) 2008 Bjoern A. Zeeb.
 * Copyright (c) 2009 James Gritton.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include "opt_ddb.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_nfs.h"

#include <sys/param.h>
#include <sys/types.h>
#include <sys/ctype.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/file.h>
#include <sys/sysproto.h>
#include <sys/malloc.h>
#include <sys/osd.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/epoch.h>
#include <sys/event.h>
#include <sys/taskqueue.h>
#include <sys/fcntl.h>
#include <sys/jail.h>
#include <sys/jaildesc.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/mman.h>
#include <sys/mutex.h>
#include <sys/racct.h>
#include <sys/rctl.h>
#include <sys/refcount.h>
#include <sys/sx.h>
#include <sys/sysent.h>
#include <sys/namei.h>
#include <sys/mount.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/uuid.h>
#include <sys/vnode.h>

#include <net/if.h>
#include <net/vnet.h>

#include <netinet/in.h>

#ifdef DDB
#include <ddb/ddb.h>
#endif /* DDB */

#include <security/mac/mac_framework.h>
#include <security/mac/mac_policy.h>
#include <security/mac/mac_syscalls.h>

#define PRISON0_HOSTUUID_MODULE "hostuuid"

MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
#ifdef RACCT
static MALLOC_DEFINE(M_PRISON_RACCT, "prison_racct", "Prison racct structures");
#endif

/* Keep struct prison prison0 and some code in kern_jail_set() readable. */
#ifdef INET
#ifdef INET6
#define _PR_IP_SADDRSEL PR_IP4_SADDRSEL|PR_IP6_SADDRSEL
#else
#define _PR_IP_SADDRSEL PR_IP4_SADDRSEL
#endif
#else /* !INET */
#ifdef INET6
#define _PR_IP_SADDRSEL PR_IP6_SADDRSEL
#else
#define _PR_IP_SADDRSEL 0
#endif
#endif

/* prison0 describes what is "real" about the system. */
struct prison prison0 = {
        .pr_id          = 0,
        .pr_name        = "0",
        .pr_ref         = 1,
        .pr_uref        = 1,
        .pr_path        = "/",
        .pr_securelevel = -1,
        .pr_devfs_rsnum = 0,
        .pr_state       = PRISON_STATE_ALIVE,
        .pr_childmax    = JAIL_MAX,
        .pr_hostuuid    = DEFAULT_HOSTUUID,
        .pr_children    = LIST_HEAD_INITIALIZER(prison0.pr_children),
#ifdef VIMAGE
        .pr_flags       = PR_HOST|PR_VNET|_PR_IP_SADDRSEL,
#else
        .pr_flags       = PR_HOST|_PR_IP_SADDRSEL,
#endif
        .pr_allow       = PR_ALLOW_PRISON0,
};
_Static_assert((PR_ALLOW_PRISON0 & ~PR_ALLOW_ALL_STATIC) == 0,
    "Bits enabled in PR_ALLOW_PRISON0 that are not statically reserved");

MTX_SYSINIT(prison0, &prison0.pr_mtx, "jail mutex", MTX_DEF);

struct bool_flags {
        const char      *name;
        const char      *noname;
        volatile u_int   flag;
};
struct jailsys_flags {
        const char      *name;
        unsigned         disable;
        unsigned         new;
};

/*
 * Handle jail teardown in a dedicated thread to avoid deadlocks from
 * vnet_destroy().
 */
TASKQUEUE_DEFINE_THREAD(jail_remove);

/* allprison, allprison_racct and lastprid are protected by allprison_lock. */
struct  sx allprison_lock;
SX_SYSINIT(allprison_lock, &allprison_lock, "allprison");
struct  prisonlist allprison = TAILQ_HEAD_INITIALIZER(allprison);
LIST_HEAD(, prison_racct) allprison_racct;
int     lastprid = 0;
int     lastdeadid = 0;

static int get_next_prid(struct prison **insprp);
static int get_next_deadid(struct prison **insprp);
static int do_jail_attach(struct thread *td, struct prison *pr, int *drflagsp);
static int prison_attach_thread_single(struct thread *td);
static void prison_attach_thread_single_end(struct thread *td);
static void prison_complete(void *context, int pending);
static void prison_deref(struct prison *pr, int flags);
static void prison_deref_kill(struct prison *pr, struct prisonlist *freeprison);
static int prison_lock_xlock(struct prison *pr, int flags);
static void prison_cleanup_locked(struct prison *pr);
static void prison_cleanup_unlocked(struct prison *pr);
static void prison_free_not_last(struct prison *pr);
static void prison_proc_free_not_last(struct prison *pr);
static void prison_proc_relink(struct prison *opr, struct prison *npr,
    struct proc *p);
static void prison_set_allow_locked(struct prison *pr, unsigned flag,
    int enable);
static char *prison_path(struct prison *pr1, struct prison *pr2);
#ifdef RACCT
static void prison_racct_attach(struct prison *pr);
static void prison_racct_modify(struct prison *pr);
static void prison_racct_detach(struct prison *pr);
#endif
static void prison_knote(struct prison *pr, long hint);

/* Flags for prison_deref */
#define PD_DEREF        0x01    /* Decrement pr_ref */
#define PD_DEUREF       0x02    /* Decrement pr_uref */
#define PD_KILL         0x04    /* Remove jail, kill processes, etc */
#define PD_LOCKED       0x10    /* pr_mtx is held */
#define PD_LIST_SLOCKED 0x20    /* allprison_lock is held shared */
#define PD_LIST_XLOCKED 0x40    /* allprison_lock is held exclusive */
#define PD_OP_FLAGS     0x07    /* Operation flags */
#define PD_LOCK_FLAGS   0x70    /* Lock status flags */

/*
 * Parameter names corresponding to PR_* flag values.  Size values are for kvm
 * as we cannot figure out the size of a sparse array, or an array without a
 * terminating entry.
 */
static struct bool_flags pr_flag_bool[] = {
        {"persist", "nopersist", PR_PERSIST},
#ifdef INET
        {"ip4.saddrsel", "ip4.nosaddrsel", PR_IP4_SADDRSEL},
#endif
#ifdef INET6
        {"ip6.saddrsel", "ip6.nosaddrsel", PR_IP6_SADDRSEL},
#endif
};
const size_t pr_flag_bool_size = sizeof(pr_flag_bool);

static struct jailsys_flags pr_flag_jailsys[] = {
        {"host", 0, PR_HOST},
#ifdef VIMAGE
        {"vnet", 0, PR_VNET},
#endif
#ifdef INET
        {"ip4", PR_IP4_USER, PR_IP4_USER},
#endif
#ifdef INET6
        {"ip6", PR_IP6_USER, PR_IP6_USER},
#endif
};
const size_t pr_flag_jailsys_size = sizeof(pr_flag_jailsys);

/*
 * Make this array full-size so dynamic parameters can be added.
 * It is protected by prison0.mtx, but lockless reading is allowed
 * with an atomic check of the flag values.
 */
static struct bool_flags pr_flag_allow[NBBY * NBPW] = {
        {"allow.set_hostname", "allow.noset_hostname", PR_ALLOW_SET_HOSTNAME},
        {"allow.sysvipc", "allow.nosysvipc", PR_ALLOW_SYSVIPC},
        {"allow.raw_sockets", "allow.noraw_sockets", PR_ALLOW_RAW_SOCKETS},
        {"allow.chflags", "allow.nochflags", PR_ALLOW_CHFLAGS},
        {"allow.mount", "allow.nomount", PR_ALLOW_MOUNT},
        {"allow.quotas", "allow.noquotas", PR_ALLOW_QUOTAS},
        {"allow.socket_af", "allow.nosocket_af", PR_ALLOW_SOCKET_AF},
        {"allow.mlock", "allow.nomlock", PR_ALLOW_MLOCK},
        {"allow.reserved_ports", "allow.noreserved_ports",
         PR_ALLOW_RESERVED_PORTS},
        {"allow.read_msgbuf", "allow.noread_msgbuf", PR_ALLOW_READ_MSGBUF},
        {"allow.unprivileged_proc_debug", "allow.nounprivileged_proc_debug",
         PR_ALLOW_UNPRIV_DEBUG},
        {"allow.suser", "allow.nosuser", PR_ALLOW_SUSER},
#ifdef VIMAGE
        {"allow.nfsd", "allow.nonfsd", PR_ALLOW_NFSD},
#endif
        {"allow.extattr", "allow.noextattr", PR_ALLOW_EXTATTR},
        {"allow.adjtime", "allow.noadjtime", PR_ALLOW_ADJTIME},
        {"allow.settime", "allow.nosettime", PR_ALLOW_SETTIME},
        {"allow.routing", "allow.norouting", PR_ALLOW_ROUTING},
        {"allow.unprivileged_parent_tampering",
            "allow.nounprivileged_parent_tampering",
            PR_ALLOW_UNPRIV_PARENT_TAMPER},
#ifdef AUDIT
        {"allow.setaudit", "allow.nosetaudit", PR_ALLOW_SETAUDIT},
#endif
};
static unsigned pr_allow_all = PR_ALLOW_ALL_STATIC;
const size_t pr_flag_allow_size = sizeof(pr_flag_allow);

#define JAIL_DEFAULT_ALLOW              (PR_ALLOW_SET_HOSTNAME | \
                                         PR_ALLOW_RESERVED_PORTS | \
                                         PR_ALLOW_UNPRIV_DEBUG | \
                                         PR_ALLOW_SUSER)
#define JAIL_DEFAULT_ENFORCE_STATFS     2
#define JAIL_DEFAULT_DEVFS_RSNUM        0
static unsigned jail_default_allow = JAIL_DEFAULT_ALLOW;
static int jail_default_enforce_statfs = JAIL_DEFAULT_ENFORCE_STATFS;
static int jail_default_devfs_rsnum = JAIL_DEFAULT_DEVFS_RSNUM;
#if defined(INET) || defined(INET6)
static unsigned jail_max_af_ips = 255;
#endif

/*
 * Initialize the parts of prison0 that can't be static-initialized with
 * constants.  This is called from proc0_init() after creating thread0 cpuset.
 */
void
prison0_init(void)
{
        uint8_t *file, *data;
        size_t size;
        char buf[sizeof(prison0.pr_hostuuid)];
#ifdef MAC
        int error __diagused;
#endif
        bool valid;

#ifdef MAC
        error = mac_prison_init(&prison0, M_WAITOK);
        MPASS(error == 0);

        mtx_unlock(&prison0.pr_mtx);
#endif
        prison0.pr_cpuset = cpuset_ref(thread0.td_cpuset);
        prison0.pr_osreldate = osreldate;
        strlcpy(prison0.pr_osrelease, osrelease, sizeof(prison0.pr_osrelease));

        /* If we have a preloaded hostuuid, use it. */
        file = preload_search_by_type(PRISON0_HOSTUUID_MODULE);
        if (file != NULL) {
                data = preload_fetch_addr(file);
                size = preload_fetch_size(file);
                if (data != NULL) {
                        /*
                         * The preloaded data may include trailing whitespace, almost
                         * certainly a newline; skip over any whitespace or
                         * non-printable characters to be safe.
                         */
                        while (size > 0 && data[size - 1] <= 0x20) {
                                size--;
                        }

                        valid = false;

                        /*
                         * Not NUL-terminated when passed from loader, but
                         * validate_uuid requires that due to using sscanf (as
                         * does the subsequent strlcpy, since it still reads
                         * past the given size to return the true length);
                         * bounce to a temporary buffer to fix.
                         */
                        if (size >= sizeof(buf))
                                goto done;

                        memcpy(buf, data, size);
                        buf[size] = '\0';

                        if (validate_uuid(buf, size, NULL, 0) != 0)
                                goto done;

                        valid = true;
                        (void)strlcpy(prison0.pr_hostuuid, buf,
                            sizeof(prison0.pr_hostuuid));

done:
                        if (bootverbose && !valid) {
                                printf("hostuuid: preload data malformed: '%.*s'\n",
                                    (int)size, data);
                        }
                }
        }
        if (bootverbose)
                printf("hostuuid: using %s\n", prison0.pr_hostuuid);
}

/*
 * struct jail_args {
 *      struct jail *jail;
 * };
 */
int
sys_jail(struct thread *td, struct jail_args *uap)
{
        uint32_t version;
        int error;
        struct jail j;

        error = copyin(uap->jail, &version, sizeof(uint32_t));
        if (error)
                return (error);

        switch (version) {
        case 0:
        {
                struct jail_v0 j0;

                /* FreeBSD single IPv4 jails. */
                bzero(&j, sizeof(struct jail));
                error = copyin(uap->jail, &j0, sizeof(struct jail_v0));
                if (error)
                        return (error);
                j.version = j0.version;
                j.path = j0.path;
                j.hostname = j0.hostname;
                j.ip4s = htonl(j0.ip_number);   /* jail_v0 is host order */
                break;
        }

        case 1:
                /*
                 * Version 1 was used by multi-IPv4 jail implementations
                 * that never made it into the official kernel.
                 */
                return (EINVAL);

        case 2: /* JAIL_API_VERSION */
                /* FreeBSD multi-IPv4/IPv6,noIP jails. */
                error = copyin(uap->jail, &j, sizeof(struct jail));
                if (error)
                        return (error);
                break;

        default:
                /* Sci-Fi jails are not supported, sorry. */
                return (EINVAL);
        }
        return (kern_jail(td, &j));
}

int
kern_jail(struct thread *td, struct jail *j)
{
        struct iovec optiov[2 * (4 + nitems(pr_flag_allow)
#ifdef INET
                            + 1
#endif
#ifdef INET6
                            + 1
#endif
                            )];
        struct uio opt;
        char *u_path, *u_hostname, *u_name;
        struct bool_flags *bf;
#ifdef INET
        uint32_t ip4s;
        struct in_addr *u_ip4;
#endif
#ifdef INET6
        struct in6_addr *u_ip6;
#endif
        size_t tmplen;
        int error, enforce_statfs;

        bzero(&optiov, sizeof(optiov));
        opt.uio_iov = optiov;
        opt.uio_iovcnt = 0;
        opt.uio_offset = -1;
        opt.uio_resid = -1;
        opt.uio_segflg = UIO_SYSSPACE;
        opt.uio_rw = UIO_READ;
        opt.uio_td = td;

        /* Set permissions for top-level jails from sysctls. */
        if (!jailed(td->td_ucred)) {
                for (bf = pr_flag_allow;
                     bf < pr_flag_allow + nitems(pr_flag_allow) &&
                        atomic_load_int(&bf->flag) != 0;
                     bf++) {
                        optiov[opt.uio_iovcnt].iov_base = __DECONST(char *,
                            (jail_default_allow & bf->flag)
                            ? bf->name : bf->noname);
                        optiov[opt.uio_iovcnt].iov_len =
                            strlen(optiov[opt.uio_iovcnt].iov_base) + 1;
                        opt.uio_iovcnt += 2;
                }
                optiov[opt.uio_iovcnt].iov_base = "enforce_statfs";
                optiov[opt.uio_iovcnt].iov_len = sizeof("enforce_statfs");
                opt.uio_iovcnt++;
                enforce_statfs = jail_default_enforce_statfs;
                optiov[opt.uio_iovcnt].iov_base = &enforce_statfs;
                optiov[opt.uio_iovcnt].iov_len = sizeof(enforce_statfs);
                opt.uio_iovcnt++;
        }

        tmplen = MAXPATHLEN + MAXHOSTNAMELEN + MAXHOSTNAMELEN;
#ifdef INET
        ip4s = (j->version == 0) ? 1 : j->ip4s;
        if (ip4s > jail_max_af_ips)
                return (EINVAL);
        tmplen += ip4s * sizeof(struct in_addr);
#else
        if (j->ip4s > 0)
                return (EINVAL);
#endif
#ifdef INET6
        if (j->ip6s > jail_max_af_ips)
                return (EINVAL);
        tmplen += j->ip6s * sizeof(struct in6_addr);
#else
        if (j->ip6s > 0)
                return (EINVAL);
#endif
        u_path = malloc(tmplen, M_TEMP, M_WAITOK);
        u_hostname = u_path + MAXPATHLEN;
        u_name = u_hostname + MAXHOSTNAMELEN;
#ifdef INET
        u_ip4 = (struct in_addr *)(u_name + MAXHOSTNAMELEN);
#endif
#ifdef INET6
#ifdef INET
        u_ip6 = (struct in6_addr *)(u_ip4 + ip4s);
#else
        u_ip6 = (struct in6_addr *)(u_name + MAXHOSTNAMELEN);
#endif
#endif
        optiov[opt.uio_iovcnt].iov_base = "path";
        optiov[opt.uio_iovcnt].iov_len = sizeof("path");
        opt.uio_iovcnt++;
        optiov[opt.uio_iovcnt].iov_base = u_path;
        error = copyinstr(j->path, u_path, MAXPATHLEN,
            &optiov[opt.uio_iovcnt].iov_len);
        if (error) {
                free(u_path, M_TEMP);
                return (error);
        }
        opt.uio_iovcnt++;
        optiov[opt.uio_iovcnt].iov_base = "host.hostname";
        optiov[opt.uio_iovcnt].iov_len = sizeof("host.hostname");
        opt.uio_iovcnt++;
        optiov[opt.uio_iovcnt].iov_base = u_hostname;
        error = copyinstr(j->hostname, u_hostname, MAXHOSTNAMELEN,
            &optiov[opt.uio_iovcnt].iov_len);
        if (error) {
                free(u_path, M_TEMP);
                return (error);
        }
        opt.uio_iovcnt++;
        if (j->jailname != NULL) {
                optiov[opt.uio_iovcnt].iov_base = "name";
                optiov[opt.uio_iovcnt].iov_len = sizeof("name");
                opt.uio_iovcnt++;
                optiov[opt.uio_iovcnt].iov_base = u_name;
                error = copyinstr(j->jailname, u_name, MAXHOSTNAMELEN,
                    &optiov[opt.uio_iovcnt].iov_len);
                if (error) {
                        free(u_path, M_TEMP);
                        return (error);
                }
                opt.uio_iovcnt++;
        }
#ifdef INET
        optiov[opt.uio_iovcnt].iov_base = "ip4.addr";
        optiov[opt.uio_iovcnt].iov_len = sizeof("ip4.addr");
        opt.uio_iovcnt++;
        optiov[opt.uio_iovcnt].iov_base = u_ip4;
        optiov[opt.uio_iovcnt].iov_len = ip4s * sizeof(struct in_addr);
        if (j->version == 0)
                u_ip4->s_addr = j->ip4s;
        else {
                error = copyin(j->ip4, u_ip4, optiov[opt.uio_iovcnt].iov_len);
                if (error) {
                        free(u_path, M_TEMP);
                        return (error);
                }
        }
        opt.uio_iovcnt++;
#endif
#ifdef INET6
        optiov[opt.uio_iovcnt].iov_base = "ip6.addr";
        optiov[opt.uio_iovcnt].iov_len = sizeof("ip6.addr");
        opt.uio_iovcnt++;
        optiov[opt.uio_iovcnt].iov_base = u_ip6;
        optiov[opt.uio_iovcnt].iov_len = j->ip6s * sizeof(struct in6_addr);
        error = copyin(j->ip6, u_ip6, optiov[opt.uio_iovcnt].iov_len);
        if (error) {
                free(u_path, M_TEMP);
                return (error);
        }
        opt.uio_iovcnt++;
#endif
        KASSERT(opt.uio_iovcnt <= nitems(optiov),
                ("kern_jail: too many iovecs (%d)", opt.uio_iovcnt));
        error = kern_jail_set(td, &opt, JAIL_CREATE | JAIL_ATTACH);
        free(u_path, M_TEMP);
        return (error);
}

/*
 * struct jail_set_args {
 *      struct iovec *iovp;
 *      unsigned int iovcnt;
 *      int flags;
 * };
 */
int
sys_jail_set(struct thread *td, struct jail_set_args *uap)
{
        struct uio *auio;
        int error;

        /* Check that we have an even number of iovecs. */
        if (uap->iovcnt & 1)
                return (EINVAL);

        error = copyinuio(uap->iovp, uap->iovcnt, &auio);
        if (error)
                return (error);
        error = kern_jail_set(td, auio, uap->flags);
        freeuio(auio);
        return (error);
}

#if defined(INET) || defined(INET6)
typedef int prison_addr_cmp_t(const void *, const void *);
typedef bool prison_addr_valid_t(const void *);
static const struct pr_family {
        size_t                  size;
        prison_addr_cmp_t       *cmp;
        prison_addr_valid_t     *valid;
        int                     ip_flag;
} pr_families[PR_FAMILY_MAX] = {
#ifdef INET
        [PR_INET] = {
                .size = sizeof(struct in_addr),
                .cmp = prison_qcmp_v4,
                .valid = prison_valid_v4,
                .ip_flag = PR_IP4_USER,
         },
#endif
#ifdef INET6
        [PR_INET6] = {
                .size = sizeof(struct in6_addr),
                .cmp = prison_qcmp_v6,
                .valid = prison_valid_v6,
                .ip_flag = PR_IP6_USER,
        },
#endif
};

/*
 * Network address lists (pr_addrs) allocation for jails.  The addresses
 * are accessed locklessly by the network stack, thus need to be protected by
 * the network epoch.
 */
struct prison_ip {
        struct epoch_context ctx;
        uint32_t        ips;
#ifdef FUTURE_C
        /*
         * XXX Variable-length automatic arrays in union may be
         * supported in future C.
         */
        union {
                char pr_ip[];
                struct in_addr pr_ip4[];
                struct in6_addr pr_ip6[];
        };
#else /* No future C :( */
        char pr_ip[];
#endif
};

static char *
PR_IP(struct prison_ip *pip, const pr_family_t af, int idx)
{
        MPASS(pip);
        MPASS(af < PR_FAMILY_MAX);
        MPASS(idx >= 0 && idx < pip->ips);

        return (pip->pr_ip + pr_families[af].size * idx);
}

static struct prison_ip *
prison_ip_alloc(const pr_family_t af, uint32_t cnt, int flags)
{
        struct prison_ip *pip;

        pip = malloc(sizeof(struct prison_ip) + cnt * pr_families[af].size,
            M_PRISON, flags);
        if (pip != NULL)
                pip->ips = cnt;
        return (pip);
}

/*
 * Allocate and copyin user supplied address list, sorting and validating.
 * kern_jail_set() helper.
 */
static struct prison_ip *
prison_ip_copyin(const pr_family_t af, void *op, uint32_t cnt)
{
        prison_addr_cmp_t *const cmp = pr_families[af].cmp;
        const size_t size = pr_families[af].size;
        struct prison_ip *pip;

        pip = prison_ip_alloc(af, cnt, M_WAITOK);
        bcopy(op, pip->pr_ip, cnt * size);
        /*
         * IP addresses are all sorted but ip[0] to preserve
         * the primary IP address as given from userland.
         * This special IP is used for unbound outgoing
         * connections as well for "loopback" traffic in case
         * source address selection cannot find any more fitting
         * address to connect from.
         */
        if (cnt > 1)
                qsort(PR_IP(pip, af, 1), cnt - 1, size, cmp);
        /*
         * Check for duplicate addresses and do some simple
         * zero and broadcast checks. If users give other bogus
         * addresses it is their problem.
         */
        for (int i = 0; i < cnt; i++) {
                if (!pr_families[af].valid(PR_IP(pip, af, i))) {
                        free(pip, M_PRISON);
                        return (NULL);
                }
                if (i + 1 < cnt &&
                    (cmp(PR_IP(pip, af, 0), PR_IP(pip, af, i + 1)) == 0 ||
                     cmp(PR_IP(pip, af, i), PR_IP(pip, af, i + 1)) == 0)) {
                        free(pip, M_PRISON);
                        return (NULL);
                }
        }

        return (pip);
}

/*
 * Allocate and dup parent prison address list.
 * kern_jail_set() helper.
 */
static void
prison_ip_dup(struct prison *ppr, struct prison *pr, const pr_family_t af)
{
        const struct prison_ip *ppip = ppr->pr_addrs[af];
        struct prison_ip *pip;

        if (ppip != NULL) {
                pip = prison_ip_alloc(af, ppip->ips, M_WAITOK);
                bcopy(ppip->pr_ip, pip->pr_ip, pip->ips * pr_families[af].size);
                pr->pr_addrs[af] = pip;
        }
}

/*
 * Make sure the new set of IP addresses is a subset of the parent's list.
 * Don't worry about the parent being unlocked, as any setting is done with
 * allprison_lock held.
 * kern_jail_set() helper.
 */
static bool
prison_ip_parent_match(struct prison_ip *ppip, struct prison_ip *pip,
    const pr_family_t af)
{
        prison_addr_cmp_t *const cmp = pr_families[af].cmp;
        int i, j;

        if (ppip == NULL)
                return (false);

        for (i = 0; i < ppip->ips; i++)
                if (cmp(PR_IP(pip, af, 0), PR_IP(ppip, af, i)) == 0)
                        break;

        if (i == ppip->ips)
                /* Main address not present in parent. */
                return (false);

        if (pip->ips > 1) {
                for (i = j = 1; i < pip->ips; i++) {
                        if (cmp(PR_IP(pip, af, i), PR_IP(ppip, af, 0)) == 0)
                                /* Equals to parent primary address. */
                                continue;
                        for (; j < ppip->ips; j++)
                                if (cmp(PR_IP(pip, af, i),
                                    PR_IP(ppip, af, j)) == 0)
                                        break;
                        if (j == ppip->ips)
                                break;
                }
                if (j == ppip->ips)
                        /* Address not present in parent. */
                        return (false);
        }
        return (true);
}

/*
 * Check for conflicting IP addresses.  We permit them if there is no more
 * than one IP on each jail.  If there is a duplicate on a jail with more
 * than one IP stop checking and return error.
 * kern_jail_set() helper.
 */
static bool
prison_ip_conflict_check(const struct prison *ppr, const struct prison *pr,
    struct prison_ip *pip, pr_family_t af)
{
        const struct prison *tppr, *tpr;
        int descend;

#ifdef VIMAGE
        for (tppr = ppr; tppr != &prison0; tppr = tppr->pr_parent)
                if (tppr->pr_flags & PR_VNET)
                        break;
#else
        tppr = &prison0;
#endif
        FOREACH_PRISON_DESCENDANT(tppr, tpr, descend) {
                if (tpr == pr ||
#ifdef VIMAGE
                    (tpr != tppr && (tpr->pr_flags & PR_VNET)) ||
#endif
                    !prison_isalive(tpr)) {
                        descend = 0;
                        continue;
                }
                if (!(tpr->pr_flags & pr_families[af].ip_flag))
                        continue;
                descend = 0;
                if (tpr->pr_addrs[af] == NULL ||
                    (pip->ips == 1 && tpr->pr_addrs[af]->ips == 1))
                        continue;
                for (int i = 0; i < pip->ips; i++)
                        if (prison_ip_check(tpr, af, PR_IP(pip, af, i)) == 0)
                                return (false);
        }

        return (true);
}

_Static_assert(offsetof(struct prison_ip, ctx) == 0,
    "prison must start with epoch context");
static void
prison_ip_free_deferred(epoch_context_t ctx)
{

        free(ctx, M_PRISON);
}

static void
prison_ip_free(struct prison_ip *pip)
{

        if (pip != NULL)
                NET_EPOCH_CALL(prison_ip_free_deferred, &pip->ctx);
}

static void
prison_ip_set(struct prison *pr, const pr_family_t af, struct prison_ip *new)
{
        struct prison_ip **mem, *old;

        mtx_assert(&pr->pr_mtx, MA_OWNED);

        mem = &pr->pr_addrs[af];

        old = *mem;
        atomic_store_ptr(mem, new);
        prison_ip_free(old);
}

/*
 * Restrict a prison's IP address list with its parent's, possibly replacing
 * it.  Return true if succeed, otherwise should redo.
 * kern_jail_set() helper.
 */
static bool
prison_ip_restrict(struct prison *pr, const pr_family_t af,
    struct prison_ip **newp)
{
        struct prison_ip *ppip = pr->pr_parent->pr_addrs[af];
        struct prison_ip *pip = pr->pr_addrs[af];
        int (*const cmp)(const void *, const void *) = pr_families[af].cmp;
        const size_t size = pr_families[af].size;
        struct prison_ip *new = newp != NULL ? *newp : NULL;
        uint32_t ips;

        mtx_assert(&pr->pr_mtx, MA_OWNED);

        /*
         * Due to epoch-synchronized access to the IP address lists we always
         * allocate a new list even if the old one has enough space.  We could
         * atomically update an IPv4 address inside a list, but that would
         * screw up sorting, and in case of IPv6 we can't even atomically write
         * one.
         */
        if (ppip == NULL) {
                if (pip != NULL)
                        prison_ip_set(pr, af, NULL);
                return (true);
        }

        if (!(pr->pr_flags & pr_families[af].ip_flag)) {
                if (new == NULL) {
                        new = prison_ip_alloc(af, ppip->ips, M_NOWAIT);
                        if (new == NULL)
                                return (false); /* Redo */
                }
                /* This has no user settings, so just copy the parent's list. */
                MPASS(new->ips == ppip->ips);
                bcopy(ppip->pr_ip, new->pr_ip, ppip->ips * size);
                prison_ip_set(pr, af, new);
                if (newp != NULL)
                        *newp = NULL; /* Used */
        } else if (pip != NULL) {
                /* Remove addresses that aren't in the parent. */
                int i;

                i = 0; /* index in pip */
                ips = 0; /* index in new */

                if (new == NULL) {
                        new = prison_ip_alloc(af, pip->ips, M_NOWAIT);
                        if (new == NULL)
                                return (false); /* Redo */
                }

                for (int pi = 0; pi < ppip->ips; pi++)
                        if (cmp(PR_IP(pip, af, 0), PR_IP(ppip, af, pi)) == 0) {
                                /* Found our primary address in parent. */
                                bcopy(PR_IP(pip, af, i), PR_IP(new, af, ips),
                                    size);
                                i++;
                                ips++;
                                break;
                        }
                for (int pi = 1; i < pip->ips; ) {
                        /* Check against primary, which is unsorted. */
                        if (cmp(PR_IP(pip, af, i), PR_IP(ppip, af, 0)) == 0) {
                                /* Matches parent's primary address. */
                                bcopy(PR_IP(pip, af, i), PR_IP(new, af, ips),
                                    size);
                                i++;
                                ips++;
                                continue;
                        }
                        /* The rest are sorted. */
                        switch (pi >= ppip->ips ? -1 :
                                cmp(PR_IP(pip, af, i), PR_IP(ppip, af, pi))) {
                        case -1:
                                i++;
                                break;
                        case 0:
                                bcopy(PR_IP(pip, af, i), PR_IP(new, af, ips),
                                    size);
                                i++;
                                pi++;
                                ips++;
                                break;
                        case 1:
                                pi++;
                                break;
                        }
                }
                if (ips == 0) {
                        if (newp == NULL || *newp == NULL)
                                prison_ip_free(new);
                        new = NULL;
                } else {
                        /* Shrink to real size */
                        KASSERT((new->ips >= ips),
                            ("Out-of-bounds write to prison_ip %p", new));
                        new->ips = ips;
                }
                prison_ip_set(pr, af, new);
                if (newp != NULL)
                        *newp = NULL; /* Used */
        }
        return (true);
}

/*
 * Fast-path check if an address belongs to a prison.
 */
int
prison_ip_check(const struct prison *pr, const pr_family_t af,
    const void *addr)
{
        int (*const cmp)(const void *, const void *) = pr_families[af].cmp;
        struct prison_ip *pip;
        int i, a, z, d;

        MPASS(mtx_owned(&pr->pr_mtx) ||
            in_epoch(net_epoch_preempt) ||
            sx_xlocked(&allprison_lock));

        pip = atomic_load_ptr(&pr->pr_addrs[af]);
        if (__predict_false(pip == NULL))
                return (EAFNOSUPPORT);

        /* Check the primary IP. */
        if (cmp(PR_IP(pip, af, 0), addr) == 0)
                return (0);

        /*
         * All the other IPs are sorted so we can do a binary search.
         */
        a = 0;
        z = pip->ips - 2;
        while (a <= z) {
                i = (a + z) / 2;
                d = cmp(PR_IP(pip, af, i + 1), addr);
                if (d > 0)
                        z = i - 1;
                else if (d < 0)
                        a = i + 1;
                else
                        return (0);
        }

        return (EADDRNOTAVAIL);
}

/*
 * Grab primary IP.  Historically required mutex, but nothing prevents
 * us to support epoch-protected access.  Is it used in fast path?
 * in{6}_jail.c helper
 */
const void *
prison_ip_get0(const struct prison *pr, const pr_family_t af)
{
        const struct prison_ip *pip = pr->pr_addrs[af];

        mtx_assert(&pr->pr_mtx, MA_OWNED);
        MPASS(pip);

        return (pip->pr_ip);
}

u_int
prison_ip_cnt(const struct prison *pr, const pr_family_t af)
{

        return (pr->pr_addrs[af]->ips);
}
#endif  /* defined(INET) || defined(INET6) */

int
kern_jail_set(struct thread *td, struct uio *optuio, int flags)
{
        struct file *jfp_out;
        struct nameidata nd;
#ifdef INET
        struct prison_ip *ip4;
#endif
#ifdef INET6
        struct prison_ip *ip6;
#endif
        struct vfsopt *opt;
        struct vfsoptlist *opts;
        struct prison *pr, *deadpr, *dinspr, *inspr, *mypr, *ppr, *tpr;
        struct ucred *jdcred;
        struct vnode *root;
        char *domain, *errmsg, *host, *name, *namelc, *p, *path, *uuid;
        char *g_path, *osrelstr;
        struct bool_flags *bf;
        struct jailsys_flags *jsf;
#if defined(INET) || defined(INET6)
        void *op;
#endif
        unsigned long hid;
        size_t namelen, onamelen, pnamelen;
#ifdef MAC
        void *mac_set_prison_data = NULL;
        int gotmaclabel;
#endif
        int created, cuflags, descend, drflags, enforce;
        int error, errmsg_len, errmsg_pos;
        int gotchildmax, gotenforce, gothid, gotrsnum, gotslevel;
        int deadid, jfd_in, jfd_out, jfd_pos, jid, jsys, len, level;
        int childmax, osreldt, rsnum, slevel;
#ifdef INET
        int ip4s;
        bool redo_ip4;
#endif
#ifdef INET6
        int ip6s;
        bool redo_ip6;
#endif
        bool maybe_changed;
        uint64_t pr_allow, ch_allow, pr_flags, ch_flags;
        uint64_t pr_allow_diff;
        unsigned tallow;
        char numbuf[12];

        mypr = td->td_ucred->cr_prison;
        if (((flags & (JAIL_CREATE | JAIL_AT_DESC)) == JAIL_CREATE) &&
            mypr->pr_childmax == 0)
                return (EPERM);
        if (flags & ~JAIL_SET_MASK)
                return (EINVAL);
        if ((flags & (JAIL_USE_DESC | JAIL_AT_DESC)) ==
            (JAIL_USE_DESC | JAIL_AT_DESC))
                return (EINVAL);

        /* Only let a single thread in the process try to attach at a time. */
        if (flags & JAIL_ATTACH) {
                error = prison_attach_thread_single(td);
                if (error != 0)
                        return (error);
        }

#ifdef INET
        ip4 = NULL;
#endif
#ifdef INET6
        ip6 = NULL;
#endif
        g_path = NULL;
        jfp_out = NULL;
        jfd_out = -1;
        prison_hold(mypr);
        /*
         * Check all the parameters before committing to anything.  Not all
         * errors can be caught early, but we may as well try.  Also, this
         * takes care of some expensive stuff (path lookup) before getting
         * the allprison lock.
         *
         * XXX Jails are not filesystems, and jail parameters are not mount
         *     options.  But it makes more sense to re-use the vfsopt code
         *     than duplicate it under a different name.
         */
        error = vfs_buildopts(optuio, &opts);
        if (error) {
                opts = NULL;
                goto done_free;
        }

        cuflags = flags & (JAIL_CREATE | JAIL_UPDATE);
        if (!cuflags) {
                error = EINVAL;
                vfs_opterror(opts, "no valid operation (create or update)");
                goto done_errmsg;
        }

        error = vfs_copyopt(opts, "desc", &jfd_in, sizeof(jfd_in));
        if (error == ENOENT) {
                if (flags & (JAIL_USE_DESC | JAIL_AT_DESC | JAIL_GET_DESC |
                    JAIL_OWN_DESC)) {
                        vfs_opterror(opts, "missing desc");
                        goto done_errmsg;
                }
                jfd_in = -1;
        } else if (error != 0)
                goto done_free;
        else {
                if (!(flags & (JAIL_USE_DESC | JAIL_AT_DESC | JAIL_GET_DESC |
                    JAIL_OWN_DESC))) {
                        error = EINVAL;
                        vfs_opterror(opts, "unexpected desc");
                        goto done_errmsg;
                }
                if (flags & JAIL_AT_DESC) {
                        /*
                         * Look up and create jails based on the
                         * descriptor's prison.
                         */
                        struct prison *jdpr;

                        error = jaildesc_find(td, jfd_in, &jdpr, NULL);
                        if (error != 0) {
                                vfs_opterror(opts, error == ENOENT ?
                                    "descriptor to dead jail" :
                                    "not a jail descriptor");
                                goto done_errmsg;
                        }
                        prison_free(mypr);
                        mypr = jdpr;
                        if ((flags & JAIL_CREATE) && mypr->pr_childmax == 0) {
                                error = EPERM;
                                goto done_free;
                        }
                }
                if (flags & (JAIL_GET_DESC | JAIL_OWN_DESC)) {
                        /* Allocate a jail descriptor to return later. */
                        error = jaildesc_alloc(td, &jfp_out, &jfd_out,
                                flags & JAIL_OWN_DESC);
                        if (error)
                                goto done_free;
                }
        }

        /*
         * Delay the permission check if using a jail descriptor,
         * until we get the descriptor's credentials.
         */
        if (!(flags & JAIL_USE_DESC)) {
                error = priv_check(td, PRIV_JAIL_SET);
                if (error == 0 && (flags & JAIL_ATTACH))
                        error = priv_check(td, PRIV_JAIL_ATTACH);
                if (error)
                        goto done_free;
        }

        error = vfs_copyopt(opts, "jid", &jid, sizeof(jid));
        if (error == ENOENT)
                jid = 0;
        else if (error != 0)
                goto done_free;

        error = vfs_copyopt(opts, "securelevel", &slevel, sizeof(slevel));
        if (error == ENOENT)
                gotslevel = 0;
        else if (error != 0)
                goto done_free;
        else
                gotslevel = 1;

        error =
            vfs_copyopt(opts, "children.max", &childmax, sizeof(childmax));
        if (error == ENOENT)
                gotchildmax = 0;
        else if (error != 0)
                goto done_free;
        else
                gotchildmax = 1;

        error = vfs_copyopt(opts, "enforce_statfs", &enforce, sizeof(enforce));
        if (error == ENOENT)
                gotenforce = 0;
        else if (error != 0)
                goto done_free;
        else if (enforce < 0 || enforce > 2) {
                error = EINVAL;
                goto done_free;
        } else
                gotenforce = 1;

        error = vfs_copyopt(opts, "devfs_ruleset", &rsnum, sizeof(rsnum));
        if (error == ENOENT)
                gotrsnum = 0;
        else if (error != 0)
                goto done_free;
        else
                gotrsnum = 1;

        pr_flags = ch_flags = 0;
        for (bf = pr_flag_bool;
             bf < pr_flag_bool + nitems(pr_flag_bool);
             bf++) {
                vfs_flagopt(opts, bf->name, &pr_flags, bf->flag);
                vfs_flagopt(opts, bf->noname, &ch_flags, bf->flag);
        }
        ch_flags |= pr_flags;
        for (jsf = pr_flag_jailsys;
             jsf < pr_flag_jailsys + nitems(pr_flag_jailsys);
             jsf++) {
                error = vfs_copyopt(opts, jsf->name, &jsys, sizeof(jsys));
                if (error == ENOENT)
                        continue;
                if (error != 0)
                        goto done_free;
                switch (jsys) {
                case JAIL_SYS_DISABLE:
                        if (!jsf->disable) {
                                error = EINVAL;
                                goto done_free;
                        }
                        pr_flags |= jsf->disable;
                        break;
                case JAIL_SYS_NEW:
                        pr_flags |= jsf->new;
                        break;
                case JAIL_SYS_INHERIT:
                        break;
                default:
                        error = EINVAL;
                        goto done_free;
                }
                ch_flags |= jsf->new | jsf->disable;
        }
        if ((flags & (JAIL_CREATE | JAIL_ATTACH)) == JAIL_CREATE
            && !(pr_flags & PR_PERSIST)) {
                error = EINVAL;
                vfs_opterror(opts, "new jail must persist or attach");
                goto done_errmsg;
        }
#ifdef VIMAGE
        if ((flags & JAIL_UPDATE) && (ch_flags & PR_VNET)) {
                error = EINVAL;
                vfs_opterror(opts, "vnet cannot be changed after creation");
                goto done_errmsg;
        }
#endif
#ifdef INET
        if ((flags & JAIL_UPDATE) && (ch_flags & PR_IP4_USER)) {
                error = EINVAL;
                vfs_opterror(opts, "ip4 cannot be changed after creation");
                goto done_errmsg;
        }
#endif
#ifdef INET6
        if ((flags & JAIL_UPDATE) && (ch_flags & PR_IP6_USER)) {
                error = EINVAL;
                vfs_opterror(opts, "ip6 cannot be changed after creation");
                goto done_errmsg;
        }
#endif

        pr_allow = ch_allow = 0;
        for (bf = pr_flag_allow;
             bf < pr_flag_allow + nitems(pr_flag_allow) &&
                atomic_load_int(&bf->flag) != 0;
             bf++) {
                vfs_flagopt(opts, bf->name, &pr_allow, bf->flag);
                vfs_flagopt(opts, bf->noname, &ch_allow, bf->flag);
        }
        ch_allow |= pr_allow;

        error = vfs_getopt(opts, "name", (void **)&name, &len);
        if (error == ENOENT)
                name = NULL;
        else if (error != 0)
                goto done_free;
        else {
                if (len == 0 || name[len - 1] != '\0') {
                        error = EINVAL;
                        goto done_free;
                }
                if (len > MAXHOSTNAMELEN) {
                        error = ENAMETOOLONG;
                        goto done_free;
                }
        }

        error = vfs_getopt(opts, "host.hostname", (void **)&host, &len);
        if (error == ENOENT)
                host = NULL;
        else if (error != 0)
                goto done_free;
        else {
                ch_flags |= PR_HOST;
                pr_flags |= PR_HOST;
                if (len == 0 || host[len - 1] != '\0') {
                        error = EINVAL;
                        goto done_free;
                }
                if (len > MAXHOSTNAMELEN) {
                        error = ENAMETOOLONG;
                        goto done_free;
                }
        }

        error = vfs_getopt(opts, "host.domainname", (void **)&domain, &len);
        if (error == ENOENT)
                domain = NULL;
        else if (error != 0)
                goto done_free;
        else {
                ch_flags |= PR_HOST;
                pr_flags |= PR_HOST;
                if (len == 0 || domain[len - 1] != '\0') {
                        error = EINVAL;
                        goto done_free;
                }
                if (len > MAXHOSTNAMELEN) {
                        error = ENAMETOOLONG;
                        goto done_free;
                }
        }

        error = vfs_getopt(opts, "host.hostuuid", (void **)&uuid, &len);
        if (error == ENOENT)
                uuid = NULL;
        else if (error != 0)
                goto done_free;
        else {
                ch_flags |= PR_HOST;
                pr_flags |= PR_HOST;
                if (len == 0 || uuid[len - 1] != '\0') {
                        error = EINVAL;
                        goto done_free;
                }
                if (len > HOSTUUIDLEN) {
                        error = ENAMETOOLONG;
                        goto done_free;
                }
        }

#ifdef COMPAT_FREEBSD32
        if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
                uint32_t hid32;

                error = vfs_copyopt(opts, "host.hostid", &hid32, sizeof(hid32));
                hid = hid32;
        } else
#endif
                error = vfs_copyopt(opts, "host.hostid", &hid, sizeof(hid));
        if (error == ENOENT)
                gothid = 0;
        else if (error != 0)
                goto done_free;
        else {
                gothid = 1;
                ch_flags |= PR_HOST;
                pr_flags |= PR_HOST;
        }

#ifdef MAC
        /* Process the mac.label vfsopt */
        error = mac_set_prison_prepare(td, opts, &mac_set_prison_data);
        if (error == ENOENT)
                gotmaclabel = 0;
        else if (error != 0)
                goto done_errmsg;
        else
                gotmaclabel = 1;
#endif

#ifdef INET
        error = vfs_getopt(opts, "ip4.addr", &op, &ip4s);
        if (error == ENOENT)
                ip4s = 0;
        else if (error != 0)
                goto done_free;
        else if (ip4s & (sizeof(struct in_addr) - 1)) {
                error = EINVAL;
                goto done_free;
        } else {
                ch_flags |= PR_IP4_USER;
                pr_flags |= PR_IP4_USER;
                if (ip4s > 0) {
                        ip4s /= sizeof(struct in_addr);
                        if (ip4s > jail_max_af_ips) {
                                error = EINVAL;
                                vfs_opterror(opts, "too many IPv4 addresses");
                                goto done_errmsg;
                        }
                        ip4 = prison_ip_copyin(PR_INET, op, ip4s);
                        if (ip4 == NULL) {
                                error = EINVAL;
                                goto done_free;
                        }
                }
        }
#endif

#ifdef INET6
        error = vfs_getopt(opts, "ip6.addr", &op, &ip6s);
        if (error == ENOENT)
                ip6s = 0;
        else if (error != 0)
                goto done_free;
        else if (ip6s & (sizeof(struct in6_addr) - 1)) {
                error = EINVAL;
                goto done_free;
        } else {
                ch_flags |= PR_IP6_USER;
                pr_flags |= PR_IP6_USER;
                if (ip6s > 0) {
                        ip6s /= sizeof(struct in6_addr);
                        if (ip6s > jail_max_af_ips) {
                                error = EINVAL;
                                vfs_opterror(opts, "too many IPv6 addresses");
                                goto done_errmsg;
                        }
                        ip6 = prison_ip_copyin(PR_INET6, op, ip6s);
                        if (ip6 == NULL) {
                                error = EINVAL;
                                goto done_free;
                        }
                }
        }
#endif

#if defined(VIMAGE) && (defined(INET) || defined(INET6))
        if ((ch_flags & PR_VNET) && (ch_flags & (PR_IP4_USER | PR_IP6_USER))) {
                error = EINVAL;
                vfs_opterror(opts,
                    "vnet jails cannot have IP address restrictions");
                goto done_errmsg;
        }
#endif

        error = vfs_getopt(opts, "osrelease", (void **)&osrelstr, &len);
        if (error == ENOENT)
                osrelstr = NULL;
        else if (error != 0)
                goto done_free;
        else {
                if (flags & JAIL_UPDATE) {
                        error = EINVAL;
                        vfs_opterror(opts,
                            "osrelease cannot be changed after creation");
                        goto done_errmsg;
                }
                if (len == 0 || osrelstr[len - 1] != '\0') {
                        error = EINVAL;
                        goto done_free;
                }
                if (len >= OSRELEASELEN) {
                        error = ENAMETOOLONG;
                        vfs_opterror(opts,
                            "osrelease string must be 1-%d bytes long",
                            OSRELEASELEN - 1);
                        goto done_errmsg;
                }
        }

        error = vfs_copyopt(opts, "osreldate", &osreldt, sizeof(osreldt));
        if (error == ENOENT)
                osreldt = 0;
        else if (error != 0)
                goto done_free;
        else {
                if (flags & JAIL_UPDATE) {
                        error = EINVAL;
                        vfs_opterror(opts,
                            "osreldate cannot be changed after creation");
                        goto done_errmsg;
                }
                if (osreldt == 0) {
                        error = EINVAL;
                        vfs_opterror(opts, "osreldate cannot be 0");
                        goto done_errmsg;
                }
        }

        root = NULL;
        error = vfs_getopt(opts, "path", (void **)&path, &len);
        if (error == ENOENT)
                path = NULL;
        else if (error != 0)
                goto done_free;
        else {
                if (flags & JAIL_UPDATE) {
                        error = EINVAL;
                        vfs_opterror(opts,
                            "path cannot be changed after creation");
                        goto done_errmsg;
                }
                if (len == 0 || path[len - 1] != '\0') {
                        error = EINVAL;
                        goto done_free;
                }
                NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path);
                error = namei(&nd);
                if (error)
                        goto done_free;
                root = nd.ni_vp;
                NDFREE_PNBUF(&nd);
                g_path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
                strlcpy(g_path, path, MAXPATHLEN);
                error = vn_path_to_global_path(td, root, g_path, MAXPATHLEN);
                if (error == 0) {
                        path = g_path;
                } else {
                        /* exit on other errors */
                        goto done_free;
                }
                if (root->v_type != VDIR) {
                        error = ENOTDIR;
                        vput(root);
                        goto done_free;
                }
                VOP_UNLOCK(root);
        }

        /*
         * Find the specified jail, or at least its parent.
         * This abuses the file error codes ENOENT and EEXIST.
         */
        pr = NULL;
        inspr = NULL;
        deadpr = NULL;
        maybe_changed = false;
        if (cuflags == JAIL_CREATE && jid == 0 && name != NULL) {
                namelc = strrchr(name, '.');
                jid = strtoul(namelc != NULL ? namelc + 1 : name, &p, 10);
                if (*p != '\0')
                        jid = 0;
        }
        sx_xlock(&allprison_lock);
        drflags = PD_LIST_XLOCKED;
        ppr = mypr;
        if (!prison_isalive(ppr)) {
                /* This jail is dying.  This process will surely follow. */
                error = EAGAIN;
                goto done_deref;
        }
        if (flags & JAIL_USE_DESC) {
                /* Get the jail from its descriptor. */
                error = jaildesc_find(td, jfd_in, &pr, &jdcred);
                if (error) {
                        vfs_opterror(opts, error == ENOENT ?
                            "descriptor to dead jail" :
                            "not a jail descriptor");
                        goto done_deref;
                }
                drflags |= PD_DEREF;
                error = priv_check_cred(jdcred, PRIV_JAIL_SET);
                if (error == 0 && (flags & JAIL_ATTACH))
                        error = priv_check_cred(jdcred, PRIV_JAIL_ATTACH);
                crfree(jdcred);
                if (error)
                        goto done_deref;
                mtx_lock(&pr->pr_mtx);
                drflags |= PD_LOCKED;
                if (cuflags == JAIL_CREATE) {
                        error = EEXIST;
                        vfs_opterror(opts, "jail %d already exists",
                            pr->pr_id);
                        goto done_deref;
                }
                if (!prison_isalive(pr)) {
                        /* While a jid can be resurrected, the prison
                         * itself cannot.
                         */
                        error = ENOENT;
                        vfs_opterror(opts, "jail %d is dying", pr->pr_id);
                        goto done_deref;
                }
                if (jid != 0 && jid != pr->pr_id) {
                        error = EINVAL;
                        vfs_opterror(opts, "cannot change jid");
                        goto done_deref;
                }
                jid = pr->pr_id;
        } else if (jid != 0) {
                if (jid < 0) {
                        error = EINVAL;
                        vfs_opterror(opts, "negative jid");
                        goto done_deref;
                }
                /*
                 * See if a requested jid already exists.  Keep track of
                 * where it can be inserted later.
                 */
                TAILQ_FOREACH(inspr, &allprison, pr_list) {
                        if (inspr->pr_id < jid)
                                continue;
                        if (inspr->pr_id > jid)
                                break;
                        if (prison_isalive(inspr)) {
                                pr = inspr;
                                mtx_lock(&pr->pr_mtx);
                                drflags |= PD_LOCKED;
                        } else {
                                /* Note a dying jail to handle later. */
                                deadpr = inspr;
                        }
                        inspr = NULL;
                        break;
                }
                if (cuflags == JAIL_CREATE && pr != NULL) {
                        /*
                         * Even creators that cannot see the jail will
                         * get EEXIST.
                         */
                        error = EEXIST;
                        vfs_opterror(opts, "jail %d already exists", jid);
                        goto done_deref;
                }
                if ((pr == NULL)
                    ? cuflags == JAIL_UPDATE
                    : !prison_ischild(mypr, pr)) {
                        /*
                         * Updaters get ENOENT for nonexistent jails,
                         * or for jails they cannot see.  The latter
                         * case is true even for CREATE | UPDATE,
                         * which normally cannot give this error.
                         */
                        error = ENOENT;
                        vfs_opterror(opts, "jail %d not found", jid);
                        goto done_deref;
                }
        }
        /*
         * If the caller provided a name, look for a jail by that name.
         * This has different semantics for creates and updates keyed by jid
         * (where the name must not already exist in a different jail),
         * and updates keyed by the name itself (where the name must exist
         * because that is the jail being updated).
         */
        namelc = NULL;
        if (name != NULL) {
                namelc = strrchr(name, '.');
                if (namelc == NULL)
                        namelc = name;
                else {
                        /*
                         * This is a hierarchical name.  Split it into the
                         * parent and child names, and make sure the parent
                         * exists or matches an already found jail.
                         */
                        if (pr != NULL) {
                                if (strncmp(name, ppr->pr_name, namelc - name)
                                    || ppr->pr_name[namelc - name] != '\0') {
                                        error = EINVAL;
                                        vfs_opterror(opts,
                                            "cannot change jail's parent");
                                        goto done_deref;
                                }
                        } else {
                                *namelc = '\0';
                                ppr = prison_find_name(mypr, name);
                                if (ppr == NULL) {
                                        error = ENOENT;
                                        vfs_opterror(opts,
                                            "jail \"%s\" not found", name);
                                        goto done_deref;
                                }
                                mtx_unlock(&ppr->pr_mtx);
                                if (!prison_isalive(ppr)) {
                                        error = ENOENT;
                                        vfs_opterror(opts,
                                            "jail \"%s\" is dying", name);
                                        goto done_deref;
                                }
                                *namelc = '.';
                        }
                        namelc++;
                }
                if (namelc[0] != '\0') {
                        pnamelen =
                            (ppr == &prison0) ? 0 : strlen(ppr->pr_name) + 1;
                        FOREACH_PRISON_CHILD(ppr, tpr) {
                                if (tpr == pr || !prison_isalive(tpr) ||
                                    strcmp(tpr->pr_name + pnamelen, namelc))
                                        continue;
                                if (cuflags == JAIL_CREATE || pr != NULL) {
                                        /*
                                         * Create, or update(jid): name must
                                         * not exist in an active sibling jail.
                                         */
                                        error = EEXIST;
                                        vfs_opterror(opts,
                                            "jail \"%s\" already exists", name);
                                        goto done_deref;
                                }
                                /* Use this jail for updates. */
                                pr = tpr;
                                mtx_lock(&pr->pr_mtx);
                                drflags |= PD_LOCKED;
                                break;
                        }
                        /*
                         * Update: name must exist if no jid is specified.
                         * As with the jid case, the jail must be currently
                         * visible, or else even CREATE | UPDATE will get
                         * an error.
                         */
                        if ((pr == NULL)
                            ? cuflags == JAIL_UPDATE
                            : !prison_isalive(pr)) {
                                error = ENOENT;
                                vfs_opterror(opts, "jail \"%s\" not found",
                                    name);
                                goto done_deref;
                        }
                }
        }
        /* Update: must provide a desc, jid, or name. */
        else if (cuflags == JAIL_UPDATE && pr == NULL) {
                error = ENOENT;
                vfs_opterror(opts, "update specified no jail");
                goto done_deref;
        }

        /* If there's no prison to update, create a new one and link it in. */
        created = pr == NULL;
        if (created) {
#ifdef MAC
                error = mac_prison_check_create(td->td_ucred, opts, flags);
                if (error != 0)
                        goto done_deref;
#endif
                for (tpr = mypr; tpr != NULL; tpr = tpr->pr_parent)
                        if (tpr->pr_childcount >= tpr->pr_childmax) {
                                error = EPERM;
                                vfs_opterror(opts, "prison limit exceeded");
                                goto done_deref;
                        }

                if (deadpr != NULL) {
                        /*
                         * The prison being created has the same ID as a dying
                         * one.  Handle this by giving the dying jail a new ID.
                         * This may cause some confusion to user space, but
                         * only to those listing dying jails.
                         */
                        deadid = get_next_deadid(&dinspr);
                        if (deadid == 0) {
                                error = EAGAIN;
                                vfs_opterror(opts, "no available jail IDs");
                                goto done_deref;
                        }
                        mtx_lock(&deadpr->pr_mtx);
                        deadpr->pr_id = deadid;
                        mtx_unlock(&deadpr->pr_mtx);
                        if (dinspr == deadpr)
                                inspr = deadpr;
                        else {
                                inspr = TAILQ_NEXT(deadpr, pr_list);
                                TAILQ_REMOVE(&allprison, deadpr, pr_list);
                                if (dinspr != NULL)
                                        TAILQ_INSERT_AFTER(&allprison, dinspr,
                                            deadpr, pr_list);
                                else
                                        TAILQ_INSERT_HEAD(&allprison, deadpr,
                                            pr_list);
                        }
                }
                if (jid == 0 && (jid = get_next_prid(&inspr)) == 0) {
                        error = EAGAIN;
                        vfs_opterror(opts, "no available jail IDs");
                        goto done_deref;
                }

                pr = malloc(sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO);
                pr->pr_state = PRISON_STATE_INVALID;
                refcount_init(&pr->pr_ref, 1);
                refcount_init(&pr->pr_uref, 0);
                drflags |= PD_DEREF;
                LIST_INIT(&pr->pr_children);
                mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF | MTX_DUPOK);
                TASK_INIT(&pr->pr_task, 0, prison_complete, pr);

                pr->pr_id = jid;
                if (inspr != NULL)
                        TAILQ_INSERT_BEFORE(inspr, pr, pr_list);
                else
                        TAILQ_INSERT_TAIL(&allprison, pr, pr_list);

                pr->pr_parent = ppr;
                prison_hold(ppr);
                prison_proc_hold(ppr);
                LIST_INSERT_HEAD(&ppr->pr_children, pr, pr_sibling);
                for (tpr = ppr; tpr != NULL; tpr = tpr->pr_parent)
                        tpr->pr_childcount++;
                pr->pr_klist = knlist_alloc(&pr->pr_mtx);

                /* Set some default values, and inherit some from the parent. */
                if (namelc == NULL)
                        namelc = "";
                if (path == NULL) {
                        path = "/";
                        root = mypr->pr_root;
                        vref(root);
                }
                strlcpy(pr->pr_hostuuid, DEFAULT_HOSTUUID, HOSTUUIDLEN);
                pr->pr_flags |= PR_HOST;
#if defined(INET) || defined(INET6)
#ifdef VIMAGE
                if (!(pr_flags & PR_VNET))
#endif
                {
#ifdef INET
                        if (!(ch_flags & PR_IP4_USER))
                                pr->pr_flags |= PR_IP4 | PR_IP4_USER;
                        else if (!(pr_flags & PR_IP4_USER)) {
                                pr->pr_flags |= ppr->pr_flags & PR_IP4;
                                prison_ip_dup(ppr, pr, PR_INET);
                        }
#endif
#ifdef INET6
                        if (!(ch_flags & PR_IP6_USER))
                                pr->pr_flags |= PR_IP6 | PR_IP6_USER;
                        else if (!(pr_flags & PR_IP6_USER)) {
                                pr->pr_flags |= ppr->pr_flags & PR_IP6;
                                prison_ip_dup(ppr, pr, PR_INET6);
                        }
#endif
                }
#endif
                /* Source address selection is always on by default. */
                pr->pr_flags |= _PR_IP_SADDRSEL;

                pr->pr_securelevel = ppr->pr_securelevel;
                pr->pr_allow = JAIL_DEFAULT_ALLOW & ppr->pr_allow;
                pr->pr_enforce_statfs = jail_default_enforce_statfs;
                pr->pr_devfs_rsnum = ppr->pr_devfs_rsnum;

                pr->pr_osreldate = osreldt ? osreldt : ppr->pr_osreldate;
                if (osrelstr == NULL)
                        strlcpy(pr->pr_osrelease, ppr->pr_osrelease,
                            sizeof(pr->pr_osrelease));
                else
                        strlcpy(pr->pr_osrelease, osrelstr,
                            sizeof(pr->pr_osrelease));

#ifdef VIMAGE
                /*
                 * Allocate a new vnet if specified.
                 *
                 * Set PR_VNET now if so, so that the vnet is disposed of
                 * properly when the jail is destroyed.
                 */
                if (pr_flags & PR_VNET) {
                        pr->pr_flags |= PR_VNET;
                        pr->pr_vnet = vnet_alloc();
                } else {
                        pr->pr_vnet = ppr->pr_vnet;
                }
#endif
                /*
                 * Allocate a dedicated cpuset for each jail.
                 * Unlike other initial settings, this may return an error.
                 */
                error = cpuset_create_root(ppr, &pr->pr_cpuset);
                if (error)
                        goto done_deref;

#ifdef MAC
                error = mac_prison_init(pr, M_WAITOK);
                MPASS(error == 0);

                mtx_assert(&pr->pr_mtx, MA_OWNED);
#else
                mtx_lock(&pr->pr_mtx);
#endif
                drflags |= PD_LOCKED;
        } else {
                /*
                 * Grab a reference for existing prisons, to ensure they
                 * continue to exist for the duration of the call.
                 */
                if (!(drflags & PD_DEREF)) {
                        prison_hold(pr);
                        drflags |= PD_DEREF;
                }
#ifdef MAC
                error = mac_prison_check_set(td->td_ucred, pr, opts, flags);
                if (error != 0)
                        goto done_deref;
#endif
#if defined(VIMAGE) && (defined(INET) || defined(INET6))
                if ((pr->pr_flags & PR_VNET) &&
                    (ch_flags & (PR_IP4_USER | PR_IP6_USER))) {
                        error = EINVAL;
                        vfs_opterror(opts,
                            "vnet jails cannot have IP address restrictions");
                        goto done_deref;
                }
#endif
#ifdef INET
                if (PR_IP4_USER & ch_flags & (pr_flags ^ pr->pr_flags)) {
                        error = EINVAL;
                        vfs_opterror(opts,
                            "ip4 cannot be changed after creation");
                        goto done_deref;
                }
#endif
#ifdef INET6
                if (PR_IP6_USER & ch_flags & (pr_flags ^ pr->pr_flags)) {
                        error = EINVAL;
                        vfs_opterror(opts,
                            "ip6 cannot be changed after creation");
                        goto done_deref;
                }
#endif
        }

        /* Do final error checking before setting anything. */
        if (gotslevel) {
                if (slevel < ppr->pr_securelevel) {
                        error = EPERM;
                        goto done_deref;
                }
        }
        if (gotchildmax) {
                if (childmax >= ppr->pr_childmax) {
                        error = EPERM;
                        goto done_deref;
                }
        }
        if (gotenforce) {
                if (enforce < ppr->pr_enforce_statfs) {
                        error = EPERM;
                        goto done_deref;
                }
        }
        if (gotrsnum) {
                /*
                 * devfs_rsnum is a uint16_t
                 */
                if (rsnum < 0 || rsnum > 65535) {
                        error = EINVAL;
                        goto done_deref;
                }
                /*
                 * Nested jails always inherit parent's devfs ruleset
                 */
                if (jailed(td->td_ucred)) {
                        if (rsnum > 0 && rsnum != ppr->pr_devfs_rsnum) {
                                error = EPERM;
                                goto done_deref;
                        } else
                                rsnum = ppr->pr_devfs_rsnum;
                }
        }
#ifdef INET
        if (ip4s > 0) {
                if ((ppr->pr_flags & PR_IP4) &&
                    !prison_ip_parent_match(ppr->pr_addrs[PR_INET], ip4,
                    PR_INET)) {
                        error = EPERM;
                        goto done_deref;
                }
                if (!prison_ip_conflict_check(ppr, pr, ip4, PR_INET)) {
                        error = EADDRINUSE;
                        vfs_opterror(opts, "IPv4 addresses clash");
                        goto done_deref;
                }
        }
#endif
#ifdef INET6
        if (ip6s > 0) {
                if ((ppr->pr_flags & PR_IP6) &&
                    !prison_ip_parent_match(ppr->pr_addrs[PR_INET6], ip6,
                    PR_INET6)) {
                        error = EPERM;
                        goto done_deref;
                }
                if (!prison_ip_conflict_check(ppr, pr, ip6, PR_INET6)) {
                        error = EADDRINUSE;
                        vfs_opterror(opts, "IPv6 addresses clash");
                        goto done_deref;
                }
        }
#endif
        onamelen = namelen = 0;
        if (namelc != NULL) {
                /* Give a default name of the jid.  Also allow the name to be
                 * explicitly the jid - but not any other number, and only in
                 * normal form (no leading zero/etc).
                 */
                if (namelc[0] == '\0')
                        snprintf(namelc = numbuf, sizeof(numbuf), "%d", jid);
                else if ((strtoul(namelc, &p, 10) != jid ||
                          namelc[0] < '1' || namelc[0] > '9') && *p == '\0') {
                        error = EINVAL;
                        vfs_opterror(opts,
                            "name cannot be numeric (unless it is the jid)");
                        goto done_deref;
                }
                /*
                 * Make sure the name isn't too long for the prison or its
                 * children.
                 */
                pnamelen = (ppr == &prison0) ? 0 : strlen(ppr->pr_name) + 1;
                onamelen = strlen(pr->pr_name + pnamelen);
                namelen = strlen(namelc);
                if (pnamelen + namelen + 1 > sizeof(pr->pr_name)) {
                        error = ENAMETOOLONG;
                        goto done_deref;
                }
                FOREACH_PRISON_DESCENDANT(pr, tpr, descend) {
                        if (strlen(tpr->pr_name) + (namelen - onamelen) >=
                            sizeof(pr->pr_name)) {
                                error = ENAMETOOLONG;
                                goto done_deref;
                        }
                }
        }
        pr_allow_diff = pr_allow & ~ppr->pr_allow;
        if (pr_allow_diff & ~PR_ALLOW_DIFFERENCES) {
                error = EPERM;
                goto done_deref;
        }

        /*
         * Let modules check their parameters.  This requires unlocking and
         * then re-locking the prison, but this is still a valid state as long
         * as allprison_lock remains xlocked.
         */
        mtx_unlock(&pr->pr_mtx);
        drflags &= ~PD_LOCKED;
        error = osd_jail_call(pr, PR_METHOD_CHECK, opts);
        if (error != 0)
                goto done_deref;
        mtx_lock(&pr->pr_mtx);
        drflags |= PD_LOCKED;

        /* At this point, all valid parameters should have been noted. */
        TAILQ_FOREACH(opt, opts, link) {
                if (!opt->seen && strcmp(opt->name, "errmsg")) {
                        error = EINVAL;
                        vfs_opterror(opts, "unknown parameter: %s", opt->name);
                        goto done_deref;
                }
        }
        maybe_changed = true;

        /* Set the parameters of the prison. */
#ifdef INET
        redo_ip4 = false;
        if (pr_flags & PR_IP4_USER) {
                pr->pr_flags |= PR_IP4;
                prison_ip_set(pr, PR_INET, ip4);
                ip4 = NULL;
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
#ifdef VIMAGE
                        if (tpr->pr_flags & PR_VNET) {
                                descend = 0;
                                continue;
                        }
#endif
                        if (!prison_ip_restrict(tpr, PR_INET, NULL)) {
                                redo_ip4 = true;
                                descend = 0;
                        }
                }
        }
#endif
#ifdef INET6
        redo_ip6 = false;
        if (pr_flags & PR_IP6_USER) {
                pr->pr_flags |= PR_IP6;
                prison_ip_set(pr, PR_INET6, ip6);
                ip6 = NULL;
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
#ifdef VIMAGE
                        if (tpr->pr_flags & PR_VNET) {
                                descend = 0;
                                continue;
                        }
#endif
                        if (!prison_ip_restrict(tpr, PR_INET6, NULL)) {
                                redo_ip6 = true;
                                descend = 0;
                        }
                }
        }
#endif
        if (gotslevel) {
                pr->pr_securelevel = slevel;
                /* Set all child jails to be at least this level. */
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
                        if (tpr->pr_securelevel < slevel)
                                tpr->pr_securelevel = slevel;
        }
        if (gotchildmax) {
                pr->pr_childmax = childmax;
                /* Set all child jails to under this limit. */
                FOREACH_PRISON_DESCENDANT_LOCKED_LEVEL(pr, tpr, descend, level)
                        if (tpr->pr_childmax > childmax - level)
                                tpr->pr_childmax = childmax > level
                                    ? childmax - level : 0;
        }
        if (gotenforce) {
                pr->pr_enforce_statfs = enforce;
                /* Pass this restriction on to the children. */
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
                        if (tpr->pr_enforce_statfs < enforce)
                                tpr->pr_enforce_statfs = enforce;
        }
        if (gotrsnum) {
                pr->pr_devfs_rsnum = rsnum;
                /* Pass this restriction on to the children. */
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
                        tpr->pr_devfs_rsnum = rsnum;
        }
        if (namelc != NULL) {
                if (ppr == &prison0)
                        strlcpy(pr->pr_name, namelc, sizeof(pr->pr_name));
                else
                        snprintf(pr->pr_name, sizeof(pr->pr_name), "%s.%s",
                            ppr->pr_name, namelc);
                /* Change this component of child names. */
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
                        bcopy(tpr->pr_name + onamelen, tpr->pr_name + namelen,
                            strlen(tpr->pr_name + onamelen) + 1);
                        bcopy(pr->pr_name, tpr->pr_name, namelen);
                }
        }
        if (path != NULL) {
                /* Try to keep a real-rooted full pathname. */
                strlcpy(pr->pr_path, path, sizeof(pr->pr_path));
                pr->pr_root = root;
                root = NULL;
        }
        if (PR_HOST & ch_flags & ~pr_flags) {
                if (pr->pr_flags & PR_HOST) {
                        /*
                         * Copy the parent's host info.  As with pr_ip4 above,
                         * the lack of a lock on the parent is not a problem;
                         * it is always set with allprison_lock at least
                         * shared, and is held exclusively here.
                         */
                        strlcpy(pr->pr_hostname, pr->pr_parent->pr_hostname,
                            sizeof(pr->pr_hostname));
                        strlcpy(pr->pr_domainname, pr->pr_parent->pr_domainname,
                            sizeof(pr->pr_domainname));
                        strlcpy(pr->pr_hostuuid, pr->pr_parent->pr_hostuuid,
                            sizeof(pr->pr_hostuuid));
                        pr->pr_hostid = pr->pr_parent->pr_hostid;
                }
        } else if (host != NULL || domain != NULL || uuid != NULL || gothid) {
                /* Set this prison, and any descendants without PR_HOST. */
                if (host != NULL)
                        strlcpy(pr->pr_hostname, host, sizeof(pr->pr_hostname));
                if (domain != NULL)
                        strlcpy(pr->pr_domainname, domain, 
                            sizeof(pr->pr_domainname));
                if (uuid != NULL)
                        strlcpy(pr->pr_hostuuid, uuid, sizeof(pr->pr_hostuuid));
                if (gothid)
                        pr->pr_hostid = hid;
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
                        if (tpr->pr_flags & PR_HOST)
                                descend = 0;
                        else {
                                if (host != NULL)
                                        strlcpy(tpr->pr_hostname,
                                            pr->pr_hostname,
                                            sizeof(tpr->pr_hostname));
                                if (domain != NULL)
                                        strlcpy(tpr->pr_domainname, 
                                            pr->pr_domainname,
                                            sizeof(tpr->pr_domainname));
                                if (uuid != NULL)
                                        strlcpy(tpr->pr_hostuuid,
                                            pr->pr_hostuuid,
                                            sizeof(tpr->pr_hostuuid));
                                if (gothid)
                                        tpr->pr_hostid = hid;
                        }
                }
        }
        pr->pr_allow = (pr->pr_allow & ~ch_allow) | pr_allow;
        if ((tallow = ch_allow & ~pr_allow))
                prison_set_allow_locked(pr, tallow, 0);
        /*
         * Persistent prisons get an extra reference, and prisons losing their
         * persist flag lose that reference.
         */
        if (ch_flags & PR_PERSIST & (pr_flags ^ pr->pr_flags)) {
                if (pr_flags & PR_PERSIST) {
                        prison_hold(pr);
                        /*
                         * This may be a new prison's first user reference,
                         * but wait to call it alive until after OSD calls
                         * have had a chance to run (and perhaps to fail).
                         */
                        refcount_acquire(&pr->pr_uref);
                } else {
                        drflags |= PD_DEUREF;
                        prison_free_not_last(pr);
                }
        }
        pr->pr_flags = (pr->pr_flags & ~ch_flags) | pr_flags;

#ifdef MAC
        /* Apply any request MAC label before we let modules do their work. */
        if (gotmaclabel) {
                error = mac_set_prison_core(td, pr, mac_set_prison_data);
                if (error) {
                        vfs_opterror(opts, "mac relabel denied");
                        goto done_deref;
                }
        }
#endif
        mtx_unlock(&pr->pr_mtx);
        drflags &= ~PD_LOCKED;
        /*
         * Any errors past this point will need to de-persist newly created
         * prisons, as well as call remove methods.
         */
        if (created)
                drflags |= PD_KILL;

#ifdef RACCT
        if (racct_enable && created)
                prison_racct_attach(pr);
#endif

        /* Locks may have prevented a complete restriction of child IP
         * addresses.  If so, allocate some more memory and try again.
         */
#ifdef INET
        while (redo_ip4) {
                ip4s = pr->pr_addrs[PR_INET]->ips;
                MPASS(ip4 == NULL);
                ip4 = prison_ip_alloc(PR_INET, ip4s, M_WAITOK);
                mtx_lock(&pr->pr_mtx);
                redo_ip4 = false;
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
#ifdef VIMAGE
                        if (tpr->pr_flags & PR_VNET) {
                                descend = 0;
                                continue;
                        }
#endif
                        if (!prison_ip_restrict(tpr, PR_INET, &ip4))
                                redo_ip4 = true;
                }
                mtx_unlock(&pr->pr_mtx);
        }
#endif
#ifdef INET6
        while (redo_ip6) {
                ip6s = pr->pr_addrs[PR_INET6]->ips;
                MPASS(ip6 == NULL);
                ip6 = prison_ip_alloc(PR_INET6, ip6s, M_WAITOK);
                mtx_lock(&pr->pr_mtx);
                redo_ip6 = false;
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
#ifdef VIMAGE
                        if (tpr->pr_flags & PR_VNET) {
                                descend = 0;
                                continue;
                        }
#endif
                        if (!prison_ip_restrict(tpr, PR_INET6, &ip6))
                                redo_ip6 = true;
                }
                mtx_unlock(&pr->pr_mtx);
        }
#endif

        /* Let the modules do their work. */
        if (created) {
                error = osd_jail_call(pr, PR_METHOD_CREATE, opts);
                if (error)
                        goto done_deref;
        }
        error = osd_jail_call(pr, PR_METHOD_SET, opts);
        if (error)
                goto done_deref;

        /*
         * A new prison is now ready to be seen; either it has gained a user
         * reference via persistence, or is about to gain one via attachment.
         */
        if (created) {
                sx_assert(&allprison_lock, SX_XLOCKED);
                prison_knote(ppr, NOTE_JAIL_CHILD | pr->pr_id);
#ifdef MAC
                /*
                 * Note that mac_prison_created() assumes that it's called in a
                 * sleepable context.
                 */
                mac_prison_created(td->td_ucred, pr);
#endif
                mtx_lock(&pr->pr_mtx);
                drflags |= PD_LOCKED;
                pr->pr_state = PRISON_STATE_ALIVE;
        }

        /*
         * Attach this process to the prison if requested.  This will
         * unlock allprison_lock, meaning changes are now user-visible.
         */
        if (flags & JAIL_ATTACH) {
#ifdef MAC
                error = mac_prison_check_attach(td->td_ucred, pr);
                if (error != 0) {
                        vfs_opterror(opts,
                            "attach operation denied by MAC policy");
                        goto done_deref;
                }
#endif
                error = do_jail_attach(td, pr, &drflags);
                if (error) {
                        vfs_opterror(opts, "attach failed");
                        goto done_deref;
                }
        }

#ifdef RACCT
        if (racct_enable && !created) {
                if (drflags & PD_LOCKED) {
                        mtx_unlock(&pr->pr_mtx);
                        drflags &= ~PD_LOCKED;
                }
                if (drflags & PD_LIST_XLOCKED) {
                        sx_xunlock(&allprison_lock);
                        drflags &= ~PD_LIST_XLOCKED;
                }
                prison_racct_modify(pr);
        }
#endif

        if (created && pr != &prison0 && (pr->pr_allow & PR_ALLOW_NFSD) != 0 &&
            (pr->pr_root->v_vflag & VV_ROOT) == 0)
                printf("Warning jail jid=%d: mountd/nfsd requires a separate"
                   " file system\n", pr->pr_id);

        /*
         * Now that the prison is fully created without error, set the
         * jail descriptor if one was requested.  This is the only
         * parameter that is returned to the caller (except the error
         * message).
         */
        if (jfd_out >= 0) {
                if (!(drflags & PD_LOCKED)) {
                        mtx_lock(&pr->pr_mtx);
                        drflags |= PD_LOCKED;
                }
                jfd_pos = 2 * vfs_getopt_pos(opts, "desc") + 1;
                if (optuio->uio_segflg == UIO_SYSSPACE)
                        *(int*)optuio->uio_iov[jfd_pos].iov_base = jfd_out;
                else
                        (void)copyout(&jfd_out,
                            optuio->uio_iov[jfd_pos].iov_base, sizeof(jfd_out));
                jaildesc_set_prison(jfp_out, pr);
        }

        drflags &= ~PD_KILL;
        td->td_retval[0] = pr->pr_id;

 done_deref:
        /*
         * Report changes to kevent.  This can happen even if the
         * system call fails, as changes might have been made before
         * the failure.
         */
        if (maybe_changed && !created)
                prison_knote(pr, NOTE_JAIL_SET);
        /* Release any temporary prison holds and/or locks. */
        if (pr != NULL)
                prison_deref(pr, drflags);
        else if (drflags & PD_LIST_SLOCKED)
                sx_sunlock(&allprison_lock);
        else if (drflags & PD_LIST_XLOCKED)
                sx_xunlock(&allprison_lock);
        if (root != NULL)
                vrele(root);
 done_errmsg:
        if (error) {
                /* Write the error message back to userspace. */
                if (vfs_getopt(opts, "errmsg", (void **)&errmsg,
                    &errmsg_len) == 0 && errmsg_len > 0) {
                        errmsg_pos = 2 * vfs_getopt_pos(opts, "errmsg") + 1;
                        if (optuio->uio_segflg == UIO_SYSSPACE)
                                bcopy(errmsg,
                                    optuio->uio_iov[errmsg_pos].iov_base,
                                    errmsg_len);
                        else
                                (void)copyout(errmsg,
                                    optuio->uio_iov[errmsg_pos].iov_base,
                                    errmsg_len);
                }
        }
 done_free:
        /* Clean up other resources. */
#ifdef INET
        prison_ip_free(ip4);
#endif
#ifdef INET6
        prison_ip_free(ip6);
#endif
#ifdef MAC
        if (mac_set_prison_data != NULL)
                mac_set_prison_finish(td, error == 0, mac_set_prison_data);
#endif
        if (jfp_out != NULL)
                fdrop(jfp_out, td);
        if (error && jfd_out >= 0)
                (void)kern_close(td, jfd_out);
        if (g_path != NULL)
                free(g_path, M_TEMP);
        if (opts != NULL)
                vfs_freeopts(opts);
        prison_free(mypr);
        if (flags & JAIL_ATTACH)
                prison_attach_thread_single_end(td);
        return (error);
}

/*
 * Find the next available prison ID.  Return the ID on success, or zero
 * on failure.  Also set a pointer to the allprison list entry the prison
 * should be inserted before.
 */
static int
get_next_prid(struct prison **insprp)
{
        struct prison *inspr;
        int jid, maxid;

        jid = lastprid % JAIL_MAX + 1;
        if (TAILQ_EMPTY(&allprison) ||
            TAILQ_LAST(&allprison, prisonlist)->pr_id < jid) {
                /*
                 * A common case is for all jails to be implicitly numbered,
                 * which means they'll go on the end of the list, at least
                 * for the first JAIL_MAX times.
                 */
                inspr = NULL;
        } else {
                /*
                 * Take two passes through the allprison list: first starting
                 * with the proposed jid, then ending with it.
                 */
                for (maxid = JAIL_MAX; maxid != 0; ) {
                        TAILQ_FOREACH(inspr, &allprison, pr_list) {
                                if (inspr->pr_id < jid)
                                        continue;
                                if (inspr->pr_id > jid) {
                                        /* Found an opening. */
                                        maxid = 0;
                                        break;
                                }
                                if (++jid > maxid) {
                                        if (lastprid == maxid || lastprid == 0)
                                        {
                                                /*
                                                 * The entire legal range
                                                 * has been traversed
                                                 */
                                                return 0;
                                        }
                                        /* Try again from the start. */
                                        jid = 1;
                                        maxid = lastprid;
                                        break;
                                }
                        }
                        if (inspr == NULL) {
                                /* Found room at the end of the list. */
                                break;
                        }
                }
        }
        *insprp = inspr;
        lastprid = jid;
        return (jid);
}

/*
 * Find the next available ID for a renumbered dead prison.  This is the same
 * as get_next_prid, but counting backward from the end of the range.
 */
static int
get_next_deadid(struct prison **dinsprp)
{
        struct prison *dinspr;
        int deadid, minid;

        deadid = lastdeadid ? lastdeadid - 1 : JAIL_MAX;
        /*
         * Take two reverse passes through the allprison list: first
         * starting with the proposed deadid, then ending with it.
         */
        for (minid = 1; minid != 0; ) {
                TAILQ_FOREACH_REVERSE(dinspr, &allprison, prisonlist, pr_list) {
                        if (dinspr->pr_id > deadid)
                                continue;
                        if (dinspr->pr_id < deadid) {
                                /* Found an opening. */
                                minid = 0;
                                break;
                        }
                        if (--deadid < minid) {
                                if (lastdeadid == minid || lastdeadid == 0)
                                {
                                        /*
                                         * The entire legal range
                                         * has been traversed
                                         */
                                        return 0;
                                }
                                /* Try again from the end. */
                                deadid = JAIL_MAX;
                                minid = lastdeadid;
                                break;
                        }
                }
                if (dinspr == NULL) {
                        /* Found room at the beginning of the list. */
                        break;
                }
        }
        *dinsprp = dinspr;
        lastdeadid = deadid;
        return (deadid);
}

/*
 * struct jail_get_args {
 *      struct iovec *iovp;
 *      unsigned int iovcnt;
 *      int flags;
 * };
 */
int
sys_jail_get(struct thread *td, struct jail_get_args *uap)
{
        struct uio *auio;
        int error;

        /* Check that we have an even number of iovecs. */
        if (uap->iovcnt & 1)
                return (EINVAL);

        error = copyinuio(uap->iovp, uap->iovcnt, &auio);
        if (error)
                return (error);
        error = kern_jail_get(td, auio, uap->flags);
        if (error == 0)
                error = copyout(auio->uio_iov, uap->iovp,
                    uap->iovcnt * sizeof(struct iovec));
        freeuio(auio);
        return (error);
}

int
kern_jail_get(struct thread *td, struct uio *optuio, int flags)
{
        struct bool_flags *bf;
        struct file *jfp_out;
        struct jailsys_flags *jsf;
        struct prison *pr, *mypr;
        struct vfsopt *opt;
        struct vfsoptlist *opts;
        char *errmsg, *name;
        int drflags, error, errmsg_len, errmsg_pos, i, jid, len, pos;
        int jfd_in, jfd_out;
        unsigned f;

        if (flags & ~JAIL_GET_MASK)
                return (EINVAL);
        if ((flags & (JAIL_USE_DESC | JAIL_AT_DESC)) ==
            (JAIL_USE_DESC | JAIL_AT_DESC))
                return (EINVAL);

        /* Get the parameter list. */
        error = vfs_buildopts(optuio, &opts);
        if (error)
                return (error);
        errmsg_pos = vfs_getopt_pos(opts, "errmsg");
        mypr = td->td_ucred->cr_prison;
        prison_hold(mypr);
        pr = NULL;
        jfp_out = NULL;
        jfd_out = -1;

        /*
         * Find the prison specified by one of: desc, lastjid, jid, name.
         */
        sx_slock(&allprison_lock);
        drflags = PD_LIST_SLOCKED;

        error = vfs_copyopt(opts, "desc", &jfd_in, sizeof(jfd_in));
        if (error == ENOENT) {
                if (flags & (JAIL_AT_DESC | JAIL_GET_DESC | JAIL_OWN_DESC)) {
                        vfs_opterror(opts, "missing desc");
                        goto done;
                }
        } else if (error == 0) {
                if (!(flags & (JAIL_USE_DESC | JAIL_AT_DESC | JAIL_GET_DESC |
                    JAIL_OWN_DESC))) {
                        error = EINVAL;
                        vfs_opterror(opts, "unexpected desc");
                        goto done;
                }
                if (flags & JAIL_USE_DESC) {
                        /* Get the jail from its descriptor. */
                        error = jaildesc_find(td, jfd_in, &pr, NULL);
                        if (error) {
                                vfs_opterror(opts, error == ENOENT ?
                                    "descriptor to dead jail" :
                                    "not a jail descriptor");
                                goto done;
                        }
                        drflags |= PD_DEREF;
                        mtx_lock(&pr->pr_mtx);
                        drflags |= PD_LOCKED;
                        goto found_prison;
                }
                if (flags & JAIL_AT_DESC) {
                        /* Look up jails based on the descriptor's prison. */
                        struct prison *jdpr;

                        error = jaildesc_find(td, jfd_in, &jdpr, NULL);
                        if (error != 0) {
                                vfs_opterror(opts, error == ENOENT ?
                                    "descriptor to dead jail" :
                                    "not a jail descriptor");
                                goto done;
                        }
                        prison_free(mypr);
                        mypr = jdpr;
                }
                if (flags & (JAIL_GET_DESC | JAIL_OWN_DESC)) {
                        /* Allocate a jail descriptor to return later. */
                        error = jaildesc_alloc(td, &jfp_out, &jfd_out,
                                flags & JAIL_OWN_DESC);
                        if (error)
                                goto done;
                }
        } else
                goto done;

        error = vfs_copyopt(opts, "lastjid", &jid, sizeof(jid));
        if (error == 0) {
                TAILQ_FOREACH(pr, &allprison, pr_list) {
                        if (pr->pr_id > jid &&
                            ((flags & JAIL_DYING) || prison_isalive(pr)) &&
                            prison_ischild(mypr, pr)) {
                                mtx_lock(&pr->pr_mtx);
                                drflags |= PD_LOCKED;
#ifdef MAC
                                /*
                                 * We special-case this one check because we
                                 * don't want MAC to break jail enumeration.  We
                                 * need to just move on to the next accessible
                                 * and alive prison.
                                 */
                                error = mac_prison_check_get(td->td_ucred, pr,
                                    opts, flags);
                                if (error != 0) {
                                        mtx_unlock(&pr->pr_mtx);
                                        drflags &= ~PD_LOCKED;
                                        continue;
                                }

                                /*
                                 * Avoid potentially expensive trip back into
                                 * the MAC framework.
                                 */
                                goto found_prison_nomac_alive;
#else
                                goto found_prison;
#endif
                        }
                }
                error = ENOENT;
                vfs_opterror(opts, "no jail after %d", jid);
                goto done;
        } else if (error != ENOENT)
                goto done;

        error = vfs_copyopt(opts, "jid", &jid, sizeof(jid));
        if (error == 0) {
                if (jid != 0) {
                        pr = prison_find_child(mypr, jid);
                        if (pr != NULL) {
                                drflags |= PD_LOCKED;
                                goto found_prison;
                        }
                        error = ENOENT;
                        vfs_opterror(opts, "jail %d not found", jid);
                        goto done;
                }
        } else if (error != ENOENT)
                goto done;

        error = vfs_getopt(opts, "name", (void **)&name, &len);
        if (error == 0) {
                if (len == 0 || name[len - 1] != '\0') {
                        error = EINVAL;
                        goto done;
                }
                pr = prison_find_name(mypr, name);
                if (pr != NULL) {
                        drflags |= PD_LOCKED;
                        goto found_prison;
                }
                error = ENOENT;
                vfs_opterror(opts, "jail \"%s\" not found", name);
                goto done;
        } else if (error != ENOENT)
                goto done;

        vfs_opterror(opts, "no jail specified");
        error = ENOENT;
        goto done;

 found_prison:
#ifdef MAC
        error = mac_prison_check_get(td->td_ucred, pr, opts, flags);
        if (error != 0)
                goto done;
#endif
        if (!(prison_isalive(pr) || (flags & JAIL_DYING))) {
                error = ENOENT;
                if (pr->pr_name[0] != '0' && isdigit(pr->pr_name[0])) {
                        vfs_opterror(opts, "jail %d is dying",
                            pr->pr_id);
                } else {
                        vfs_opterror(opts, "jail \"%s\" (%d) is dying",
                            pr->pr_name, pr->pr_id);
                }
                goto done;
        }
#ifdef MAC
 found_prison_nomac_alive:
#endif
        /* Get the parameters of the prison. */
        if (!(drflags & PD_DEREF)) {
                prison_hold(pr);
                drflags |= PD_DEREF;
        }
        td->td_retval[0] = pr->pr_id;
        if (jfd_out >= 0) {
                error = vfs_setopt(opts, "desc", &jfd_out, sizeof(jfd_out));
                if (error != 0 && error != ENOENT)
                        goto done;
                jaildesc_set_prison(jfp_out, pr);
        }
        error = vfs_setopt(opts, "jid", &pr->pr_id, sizeof(pr->pr_id));
        if (error != 0 && error != ENOENT)
                goto done;
        i = (pr->pr_parent == mypr) ? 0 : pr->pr_parent->pr_id;
        error = vfs_setopt(opts, "parent", &i, sizeof(i));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopts(opts, "name", prison_name(mypr, pr));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopt(opts, "cpuset.id", &pr->pr_cpuset->cs_id,
            sizeof(pr->pr_cpuset->cs_id));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopts(opts, "path", prison_path(mypr, pr));
        if (error != 0 && error != ENOENT)
                goto done;
#ifdef INET
        error = vfs_setopt_part(opts, "ip4.addr", pr->pr_addrs[PR_INET]->pr_ip,
            pr->pr_addrs[PR_INET] ? pr->pr_addrs[PR_INET]->ips *
            pr_families[PR_INET].size : 0 );
        if (error != 0 && error != ENOENT)
                goto done;
#endif
#ifdef INET6
        error = vfs_setopt_part(opts, "ip6.addr", pr->pr_addrs[PR_INET6]->pr_ip,
            pr->pr_addrs[PR_INET6] ? pr->pr_addrs[PR_INET6]->ips *
            pr_families[PR_INET6].size : 0 );
        if (error != 0 && error != ENOENT)
                goto done;
#endif
        error = vfs_setopt(opts, "securelevel", &pr->pr_securelevel,
            sizeof(pr->pr_securelevel));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopt(opts, "children.cur", &pr->pr_childcount,
            sizeof(pr->pr_childcount));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopt(opts, "children.max", &pr->pr_childmax,
            sizeof(pr->pr_childmax));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopts(opts, "host.hostname", pr->pr_hostname);
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopts(opts, "host.domainname", pr->pr_domainname);
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopts(opts, "host.hostuuid", pr->pr_hostuuid);
        if (error != 0 && error != ENOENT)
                goto done;
#ifdef COMPAT_FREEBSD32
        if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
                uint32_t hid32 = pr->pr_hostid;

                error = vfs_setopt(opts, "host.hostid", &hid32, sizeof(hid32));
        } else
#endif
        error = vfs_setopt(opts, "host.hostid", &pr->pr_hostid,
            sizeof(pr->pr_hostid));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopt(opts, "enforce_statfs", &pr->pr_enforce_statfs,
            sizeof(pr->pr_enforce_statfs));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopt(opts, "devfs_ruleset", &pr->pr_devfs_rsnum,
            sizeof(pr->pr_devfs_rsnum));
        if (error != 0 && error != ENOENT)
                goto done;
        for (bf = pr_flag_bool;
             bf < pr_flag_bool + nitems(pr_flag_bool);
             bf++) {
                i = (pr->pr_flags & bf->flag) ? 1 : 0;
                error = vfs_setopt(opts, bf->name, &i, sizeof(i));
                if (error != 0 && error != ENOENT)
                        goto done;
                i = !i;
                error = vfs_setopt(opts, bf->noname, &i, sizeof(i));
                if (error != 0 && error != ENOENT)
                        goto done;
        }
        for (jsf = pr_flag_jailsys;
             jsf < pr_flag_jailsys + nitems(pr_flag_jailsys);
             jsf++) {
                f = pr->pr_flags & (jsf->disable | jsf->new);
                i = (f != 0 && f == jsf->disable) ? JAIL_SYS_DISABLE
                    : (f == jsf->new) ? JAIL_SYS_NEW
                    : JAIL_SYS_INHERIT;
                error = vfs_setopt(opts, jsf->name, &i, sizeof(i));
                if (error != 0 && error != ENOENT)
                        goto done;
        }
        for (bf = pr_flag_allow;
             bf < pr_flag_allow + nitems(pr_flag_allow) &&
                atomic_load_int(&bf->flag) != 0;
             bf++) {
                i = (pr->pr_allow & bf->flag) ? 1 : 0;
                error = vfs_setopt(opts, bf->name, &i, sizeof(i));
                if (error != 0 && error != ENOENT)
                        goto done;
                i = !i;
                error = vfs_setopt(opts, bf->noname, &i, sizeof(i));
                if (error != 0 && error != ENOENT)
                        goto done;
        }
        i = !prison_isalive(pr);
        error = vfs_setopt(opts, "dying", &i, sizeof(i));
        if (error != 0 && error != ENOENT)
                goto done;
        i = !i;
        error = vfs_setopt(opts, "nodying", &i, sizeof(i));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopt(opts, "osreldate", &pr->pr_osreldate,
            sizeof(pr->pr_osreldate));
        if (error != 0 && error != ENOENT)
                goto done;
        error = vfs_setopts(opts, "osrelease", pr->pr_osrelease);
        if (error != 0 && error != ENOENT)
                goto done;

#ifdef MAC
        /*
         * We get the MAC label last because we'll let the MAC framework drop
         * pr_mtx to externalize the label.
         */
        error = mac_get_prison(td, pr, opts);
        mtx_assert(&pr->pr_mtx, MA_NOTOWNED);
        drflags &= ~PD_LOCKED;
        if (error != 0 && error != ENOENT)
                goto done;
#else
        mtx_unlock(&pr->pr_mtx);
        drflags &= ~PD_LOCKED;
#endif

        /* Get the module parameters. */
        error = osd_jail_call(pr, PR_METHOD_GET, opts);
        if (error)
                goto done;
        prison_deref(pr, drflags);
        pr = NULL;
        drflags = 0;

        /* By now, all parameters should have been noted. */
        TAILQ_FOREACH(opt, opts, link) {
                if (!opt->seen &&
                    (strstr(opt->name, JAIL_META_PRIVATE ".") == opt->name ||
                    strstr(opt->name, JAIL_META_SHARED ".") == opt->name)) {
                        /* Communicate back a missing key. */
                        free(opt->value, M_MOUNT);
                        opt->value = NULL;
                        opt->len = 0;
                        continue;
                }
                if (!opt->seen && strcmp(opt->name, "errmsg")) {
                        error = EINVAL;
                        vfs_opterror(opts, "unknown parameter: %s", opt->name);
                        goto done;
                }
        }

        /* Write the fetched parameters back to userspace. */
        error = 0;
        TAILQ_FOREACH(opt, opts, link) {
                if (opt->pos >= 0 && opt->pos != errmsg_pos) {
                        pos = 2 * opt->pos + 1;
                        optuio->uio_iov[pos].iov_len = opt->len;
                        if (opt->value != NULL) {
                                if (optuio->uio_segflg == UIO_SYSSPACE) {
                                        bcopy(opt->value,
                                            optuio->uio_iov[pos].iov_base,
                                            opt->len);
                                } else {
                                        error = copyout(opt->value,
                                            optuio->uio_iov[pos].iov_base,
                                            opt->len);
                                        if (error)
                                                break;
                                }
                        }
                }
        }

 done:
        /* Release any temporary prison holds and/or locks. */
        if (pr != NULL)
                prison_deref(pr, drflags);
        else if (drflags & PD_LIST_SLOCKED)
                sx_sunlock(&allprison_lock);
        else if (drflags & PD_LIST_XLOCKED)
                sx_xunlock(&allprison_lock);
        /* Clean up other resources. */
        if (jfp_out != NULL)
                (void)fdrop(jfp_out, td);
        if (error && jfd_out >= 0)
                (void)kern_close(td, jfd_out);
        if (error && errmsg_pos >= 0) {
                /* Write the error message back to userspace. */
                vfs_getopt(opts, "errmsg", (void **)&errmsg, &errmsg_len);
                errmsg_pos = 2 * errmsg_pos + 1;
                if (errmsg_len > 0) {
                        if (optuio->uio_segflg == UIO_SYSSPACE)
                                bcopy(errmsg,
                                    optuio->uio_iov[errmsg_pos].iov_base,
                                    errmsg_len);
                        else
                                (void)copyout(errmsg,
                                    optuio->uio_iov[errmsg_pos].iov_base,
                                    errmsg_len);
                }
        }
        vfs_freeopts(opts);
        prison_free(mypr);
        return (error);
}

/*
 * struct jail_remove_args {
 *      int jid;
 * };
 */
int
sys_jail_remove(struct thread *td, struct jail_remove_args *uap)
{
        struct prison *pr;
        int error;

        error = priv_check(td, PRIV_JAIL_REMOVE);
        if (error)
                return (error);

        sx_xlock(&allprison_lock);
        pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
        if (pr == NULL) {
                sx_xunlock(&allprison_lock);
                return (EINVAL);
        }
#ifdef MAC
        error = mac_prison_check_remove(td->td_ucred, pr);
        if (error != 0) {
                mtx_unlock(&pr->pr_mtx);
                sx_xunlock(&allprison_lock);
                return (error);
        }
#endif
        prison_hold(pr);
        prison_remove(pr);
        return (0);
}

/*
 * struct jail_remove_jd_args {
 *      int fd;
 * };
 */
int
sys_jail_remove_jd(struct thread *td, struct jail_remove_jd_args *uap)
{
        struct prison *pr;
        struct ucred *jdcred;
        int error;

        error = jaildesc_find(td, uap->fd, &pr, &jdcred);
        if (error)
                return (error);
        error = priv_check_cred(jdcred, PRIV_JAIL_REMOVE);
        crfree(jdcred);
#ifdef MAC
        if (error == 0)
                error = mac_prison_check_remove(td->td_ucred, pr);
#endif
        if (error) {
                prison_free(pr);
                return (error);
        }
        sx_xlock(&allprison_lock);
        mtx_lock(&pr->pr_mtx);
        prison_remove(pr);
        return (0);
}

/*
 * Begin the removal process for a prison.  The allprison lock should
 * be held exclusively, and the prison should be both locked and held.
 */
void
prison_remove(struct prison *pr)
{
        sx_assert(&allprison_lock, SA_XLOCKED);
        mtx_assert(&pr->pr_mtx, MA_OWNED);
        prison_deref(pr, PD_KILL | PD_DEREF | PD_LOCKED | PD_LIST_XLOCKED);
}

/*
 * struct jail_attach_args {
 *      int jid;
 * };
 */
int
sys_jail_attach(struct thread *td, struct jail_attach_args *uap)
{
        struct prison *pr;
        int drflags, error;

        error = priv_check(td, PRIV_JAIL_ATTACH);
        if (error)
                return (error);
        /* Only let a single thread in the process try to attach at a time. */
        error = prison_attach_thread_single(td);
        if (error != 0)
                return (error);

        sx_slock(&allprison_lock);
        drflags = PD_LIST_SLOCKED;
        pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
        if (pr == NULL) {
                error = EINVAL;
                goto done;
        }
        drflags |= PD_LOCKED;

#ifdef MAC
        error = mac_prison_check_attach(td->td_ucred, pr);
        if (error != 0)
                goto done;
#endif

        /* Do not allow a process to attach to a prison that is not alive. */
        if (!prison_isalive(pr)) {
                error = EINVAL;
                goto done;
        }

        error = do_jail_attach(td, pr, &drflags);

 done:
        prison_deref(pr, drflags);
        prison_attach_thread_single_end(td);
        return (error);
}

/*
 * struct jail_attach_jd_args {
 *      int fd;
 * };
 */
int
sys_jail_attach_jd(struct thread *td, struct jail_attach_jd_args *uap)
{
        struct prison *pr;
        struct ucred *jdcred;
        int drflags, error;

        /* Only let a single thread in the process try to attach at a time. */
        error = prison_attach_thread_single(td);
        if (error != 0)
                return (error);

        sx_slock(&allprison_lock);
        drflags = PD_LIST_SLOCKED;
        pr = NULL;
        error = jaildesc_find(td, uap->fd, &pr, &jdcred);
        if (error)
                goto done;
        drflags |= PD_DEREF;
        error = priv_check_cred(jdcred, PRIV_JAIL_ATTACH);
#ifdef MAC
        if (error == 0)
                error = mac_prison_check_attach(td->td_ucred, pr);
#endif
        crfree(jdcred);
        if (error)
                goto done;

        /* Do not allow a process to attach to a prison that is not alive. */
        if (!prison_isalive(pr)) {
                error = EINVAL;
                goto done;
        }

        error = do_jail_attach(td, pr, &drflags);

 done:
        prison_deref(pr, drflags);
        prison_attach_thread_single_end(td);
        return (error);
}

/*
 * Attach the current process to a prison.  On entry, the allprison
 * lock should be at least shared.  On exit, both it and the prison
 * itself will be unlocked, which will be refelected in *drflagsp.
 */
static int
do_jail_attach(struct thread *td, struct prison *pr, int *drflagsp)
{
        struct proc *p;
        struct ucred *newcred, *oldcred;
        int drflags, error;

        sx_assert(&allprison_lock, SX_LOCKED);
        KASSERT(prison_isvalid(pr), ("Attaching to invalid prison %p", pr));
        /*
         * Note the caller's locking state, but gain and track our own
         * references.  The caller will see that locks have been
         * dropped (which isn't true now, but will be after OSD calls).
         */
        prison_hold(pr);
        refcount_acquire(&pr->pr_uref);
        drflags = PD_DEREF | PD_DEUREF | (*drflagsp & PD_LOCK_FLAGS);
        *drflagsp &= PD_OP_FLAGS;

        /* Let modules do whatever they need to prepare for attaching. */
        if (drflags & PD_LOCKED) {
                mtx_unlock(&pr->pr_mtx);
                drflags &= ~PD_LOCKED;
        }
        error = osd_jail_call(pr, PR_METHOD_ATTACH, td);
        if (error)
                goto e_revert_osd;
        sx_unlock(&allprison_lock);
        drflags &= ~(PD_LIST_SLOCKED | PD_LIST_XLOCKED);

        /*
         * Reparent the newly attached process to this jail.
         */
        p = td->td_proc;
        error = cpuset_setproc_update_set(p, pr->pr_cpuset);
        if (error)
                goto e_revert_osd;

        vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY);
        if ((error = change_dir(pr->pr_root, td)) != 0)
                goto e_unlock;
#ifdef MAC
        if ((error = mac_vnode_check_chroot(td->td_ucred, pr->pr_root)))
                goto e_unlock;
#endif
        VOP_UNLOCK(pr->pr_root);
        if ((error = pwd_chroot_chdir(td, pr->pr_root)))
                goto e_revert_osd;

        newcred = crget();
        PROC_LOCK(p);
        oldcred = crcopysafe(p, newcred);
        newcred->cr_prison = pr;
#ifdef RACCT
        racct_proc_ucred_changed(p, oldcred, newcred);
#endif
#ifdef RCTL
        crhold(newcred);
#endif
        /*
         * Takes over 'newcred''s reference, so 'newcred' must not be used
         * besides this point except on RCTL where we took an additional
         * reference above.
         */
        proc_set_cred(p, newcred);
        setsugid(p);
        PROC_UNLOCK(p);
#ifdef RCTL
        rctl_proc_ucred_changed(p, newcred);
        crfree(newcred);
#endif
        prison_proc_relink(oldcred->cr_prison, pr, p);
        prison_deref(oldcred->cr_prison, drflags);
        crfree(oldcred);
        prison_knote(pr, NOTE_JAIL_ATTACH | td->td_proc->p_pid);
#ifdef MAC
        /*
         * Note that mac_prison_attached() assumes that it's called in a
         * sleepable context.
         */
        mac_prison_attached(td->td_ucred, pr, td->td_proc);
#endif

        /*
         * If the prison was killed while changing credentials, die along
         * with it.
         */
        if (!prison_isalive(pr)) {
                PROC_LOCK(p);
                kern_psignal(p, SIGKILL);
                PROC_UNLOCK(p);
        }

        return (0);

 e_unlock:
        VOP_UNLOCK(pr->pr_root);
 e_revert_osd:
        /* Tell modules this process is still in its old jail after all. */
        if (!(drflags & (PD_LIST_SLOCKED | PD_LIST_XLOCKED))) {
                sx_slock(&allprison_lock);
                drflags |= PD_LIST_SLOCKED;
        }
        (void)osd_jail_call(td->td_ucred->cr_prison, PR_METHOD_ATTACH, td);
        prison_deref(pr, drflags);
        return (error);
}

/*
 * Only one thread in a process should try to attach to a jail, or
 * they might end up with a process root from one prison, but attached
 * to the jail of another.  Enforce this by making the process run in
 * single-threaded mode for the duration of the system call, which
 * also prevents other related calls such as chroot.
 */
static int
prison_attach_thread_single(struct thread *td)
{
        struct proc *p;
        int error;

        error = 0;
        p = td->td_proc;
        if ((atomic_load_int(&p->p_flag) & P_HADTHREADS) != 0) {
                PROC_LOCK(p);
                if (thread_single(p, SINGLE_BOUNDARY))
                        error = ERESTART;
                PROC_UNLOCK(p);
        }
        return (error);
}

static void
prison_attach_thread_single_end(struct thread *td)
{
        struct proc *p;

        p = td->td_proc;
        if ((atomic_load_int(&p->p_flag) & P_HADTHREADS) != 0) {
                PROC_LOCK(p);
                thread_single_end(p, SINGLE_BOUNDARY);
                PROC_UNLOCK(p);
        }
}

/*
 * Returns a locked prison instance, or NULL on failure.
 */
struct prison *
prison_find(int prid)
{
        struct prison *pr;

        sx_assert(&allprison_lock, SX_LOCKED);
        TAILQ_FOREACH(pr, &allprison, pr_list) {
                if (pr->pr_id < prid)
                        continue;
                if (pr->pr_id > prid)
                        break;
                KASSERT(prison_isvalid(pr), ("Found invalid prison %p", pr));
                mtx_lock(&pr->pr_mtx);
                return (pr);
        }
        return (NULL);
}

/*
 * Find a prison that is a descendant of mypr.  Returns a locked prison or NULL.
 */
struct prison *
prison_find_child(struct prison *mypr, int prid)
{
        struct prison *pr;
        int descend;

        sx_assert(&allprison_lock, SX_LOCKED);
        FOREACH_PRISON_DESCENDANT(mypr, pr, descend) {
                if (pr->pr_id == prid) {
                        KASSERT(prison_isvalid(pr),
                            ("Found invalid prison %p", pr));
                        mtx_lock(&pr->pr_mtx);
                        return (pr);
                }
        }
        return (NULL);
}

/*
 * Look for the name relative to mypr.  Returns a locked prison or NULL.
 */
struct prison *
prison_find_name(struct prison *mypr, const char *name)
{
        struct prison *pr, *deadpr;
        size_t mylen;
        int descend;

        sx_assert(&allprison_lock, SX_LOCKED);
        mylen = (mypr == &prison0) ? 0 : strlen(mypr->pr_name) + 1;
        deadpr = NULL;
        FOREACH_PRISON_DESCENDANT(mypr, pr, descend) {
                if (!strcmp(pr->pr_name + mylen, name)) {
                        KASSERT(prison_isvalid(pr),
                            ("Found invalid prison %p", pr));
                        if (prison_isalive(pr)) {
                                mtx_lock(&pr->pr_mtx);
                                return (pr);
                        }
                        deadpr = pr;
                }
        }
        /* There was no valid prison - perhaps there was a dying one. */
        if (deadpr != NULL)
                mtx_lock(&deadpr->pr_mtx);
        return (deadpr);
}

/*
 * See if a prison has the specific flag set.  The prison should be locked,
 * unless checking for flags that are only set at jail creation (such as
 * PR_IP4 and PR_IP6), or only the single bit is examined, without regard
 * to any other prison data.
 */
bool
prison_flag(struct ucred *cred, unsigned flag)
{

        return ((cred->cr_prison->pr_flags & flag) != 0);
}

/*
 * See if a prison has the specific allow flag set.
 * The prison *should* be locked, or only a single bit is examined, without
 * regard to any other prison data.
 */
bool
prison_allow(struct ucred *cred, unsigned flag)
{

        return ((cred->cr_prison->pr_allow & flag) != 0);
}

/*
 * Hold a prison reference, by incrementing pr_ref.  It is generally
 * an error to hold a prison that does not already have a reference.
 * A prison record will remain valid as long as it has at least one
 * reference, and will not be removed as long as either the prison
 * mutex or the allprison lock is held (allprison_lock may be shared).
 */
void
prison_hold_locked(struct prison *pr)
{

        /* Locking is no longer required. */
        prison_hold(pr);
}

void
prison_hold(struct prison *pr)
{
#ifdef INVARIANTS
        int was_valid = refcount_acquire_if_not_zero(&pr->pr_ref);

        KASSERT(was_valid,
            ("Trying to hold dead prison %p (jid=%d).", pr, pr->pr_id));
#else
        refcount_acquire(&pr->pr_ref);
#endif
}

/*
 * Remove a prison reference.  If that was the last reference, the
 * prison will be removed (at a later time).
 */
void
prison_free_locked(struct prison *pr)
{

        mtx_assert(&pr->pr_mtx, MA_OWNED);
        /*
         * Locking is no longer required, but unlock because the caller
         * expects it.
         */
        mtx_unlock(&pr->pr_mtx);
        prison_free(pr);
}

void
prison_free(struct prison *pr)
{

        KASSERT(refcount_load(&pr->pr_ref) > 0,
            ("Trying to free dead prison %p (jid=%d).",
             pr, pr->pr_id));
        if (!refcount_release_if_not_last(&pr->pr_ref)) {
                /*
                 * Don't remove the last reference in this context,
                 * in case there are locks held.
                 */
                taskqueue_enqueue(taskqueue_jail_remove, &pr->pr_task);
        }
}

static void
prison_free_not_last(struct prison *pr)
{
#ifdef INVARIANTS
        int lastref;

        KASSERT(refcount_load(&pr->pr_ref) > 0,
            ("Trying to free dead prison %p (jid=%d).",
             pr, pr->pr_id));
        lastref = refcount_release(&pr->pr_ref);
        KASSERT(!lastref,
            ("prison_free_not_last freed last ref on prison %p (jid=%d).",
             pr, pr->pr_id));
#else
        refcount_release(&pr->pr_ref);
#endif
}

/*
 * Hold a prison for user visibility, by incrementing pr_uref.
 * It is generally an error to hold a prison that isn't already
 * user-visible, except through the jail system calls.  It is also
 * an error to hold an invalid prison.  A prison record will remain
 * alive as long as it has at least one user reference, and will not
 * be set to the dying state until the prison mutex and allprison_lock
 * are both freed.
 */
void
prison_proc_hold(struct prison *pr)
{
#ifdef INVARIANTS
        int was_alive = refcount_acquire_if_not_zero(&pr->pr_uref);

        KASSERT(was_alive,
            ("Cannot add a process to a non-alive prison (jid=%d)", pr->pr_id));
#else
        refcount_acquire(&pr->pr_uref);
#endif
}

/*
 * Remove a prison user reference.  If it was the last reference, the
 * prison will be considered "dying", and may be removed once all of
 * its references are dropped.
 */
void
prison_proc_free(struct prison *pr)
{

        /*
         * Locking is only required when releasing the last reference.
         * This allows assurance that a locked prison will remain alive
         * until it is unlocked.
         */
        KASSERT(refcount_load(&pr->pr_uref) > 0,
            ("Trying to kill a process in a dead prison (jid=%d)", pr->pr_id));
        if (!refcount_release_if_not_last(&pr->pr_uref)) {
                /*
                 * Don't remove the last user reference in this context,
                 * which is expected to be a process that is not only locked,
                 * but also half dead.  Add a reference so any calls to
                 * prison_free() won't re-submit the task.
                 */
                prison_hold(pr);
                mtx_lock(&pr->pr_mtx);
                KASSERT(!(pr->pr_flags & PR_COMPLETE_PROC),
                    ("Redundant last reference in prison_proc_free (jid=%d)",
                     pr->pr_id));
                pr->pr_flags |= PR_COMPLETE_PROC;
                mtx_unlock(&pr->pr_mtx);
                taskqueue_enqueue(taskqueue_jail_remove, &pr->pr_task);
        }
}

static void
prison_proc_free_not_last(struct prison *pr)
{
#ifdef INVARIANTS
        int lastref;

        KASSERT(refcount_load(&pr->pr_uref) > 0,
            ("Trying to free dead prison %p (jid=%d).",
             pr, pr->pr_id));
        lastref = refcount_release(&pr->pr_uref);
        KASSERT(!lastref,
            ("prison_proc_free_not_last freed last uref on prison %p (jid=%d).",
             pr, pr->pr_id));
#else
        refcount_release(&pr->pr_uref);
#endif
}

void
prison_proc_link(struct prison *pr, struct proc *p)
{

        sx_assert(&allproc_lock, SA_XLOCKED);
        LIST_INSERT_HEAD(&pr->pr_proclist, p, p_jaillist);
}

void
prison_proc_unlink(struct prison *pr, struct proc *p)
{

        sx_assert(&allproc_lock, SA_XLOCKED);
        LIST_REMOVE(p, p_jaillist);
}

static void
prison_proc_relink(struct prison *opr, struct prison *npr, struct proc *p)
{

        sx_xlock(&allproc_lock);
        prison_proc_unlink(opr, p);
        prison_proc_link(npr, p);
        sx_xunlock(&allproc_lock);
}

/*
 * Complete a call to either prison_free or prison_proc_free.
 */
static void
prison_complete(void *context, int pending)
{
        struct prison *pr = context;
        int drflags;

        /*
         * This could be called to release the last reference, or the last
         * user reference (plus the reference held in prison_proc_free).
         */
        drflags = prison_lock_xlock(pr, PD_DEREF);
        if (pr->pr_flags & PR_COMPLETE_PROC) {
                pr->pr_flags &= ~PR_COMPLETE_PROC;
                drflags |= PD_DEUREF;
        }
        prison_deref(pr, drflags);
}

static void
prison_kill_processes_cb(struct proc *p, void *arg __unused)
{

        kern_psignal(p, SIGKILL);
}

/*
 * Note the iteration does not guarantee acting on all processes.
 * Most notably there may be fork or jail_attach in progress.
 */
void
prison_proc_iterate(struct prison *pr, void (*cb)(struct proc *, void *),
    void *cbarg)
{
        struct prison *ppr;
        struct proc *p;

        if (atomic_load_int(&pr->pr_childcount) == 0) {
                sx_slock(&allproc_lock);
                LIST_FOREACH(p, &pr->pr_proclist, p_jaillist) {
                        if (p->p_state == PRS_NEW)
                                continue;
                        PROC_LOCK(p);
                        cb(p, cbarg);
                        PROC_UNLOCK(p);
                }
                sx_sunlock(&allproc_lock);
                if (atomic_load_int(&pr->pr_childcount) == 0)
                        return;
                /*
                 * Some jails popped up during the iteration, fall through to a
                 * system-wide search.
                 */
        }

        sx_slock(&allproc_lock);
        FOREACH_PROC_IN_SYSTEM(p) {
                PROC_LOCK(p);
                if (p->p_state != PRS_NEW && p->p_ucred != NULL) {
                        for (ppr = p->p_ucred->cr_prison; ppr != NULL;
                            ppr = ppr->pr_parent) {
                                if (ppr == pr) {
                                        cb(p, cbarg);
                                        break;
                                }
                        }
                }
                PROC_UNLOCK(p);
        }
        sx_sunlock(&allproc_lock);
}

/*
 * Remove a prison reference and/or user reference (usually).
 * This assumes context that allows sleeping (for allprison_lock),
 * with no non-sleeping locks held, except perhaps the prison itself.
 * If there are no more references, release and delist the prison.
 * On completion, the prison lock and the allprison lock are both
 * unlocked.
 */
static void
prison_deref(struct prison *pr, int flags)
{
        struct prisonlist freeprison;
        struct prison *killpr, *rpr, *ppr, *tpr;

        killpr = NULL;
        TAILQ_INIT(&freeprison);
        /*
         * Release this prison as requested, which may cause its parent
         * to be released, and then maybe its grandparent, etc.
         */
        for (;;) {
                if (flags & PD_KILL) {
                        /* Kill the prison and its descendents. */
                        KASSERT(pr != &prison0,
                            ("prison_deref trying to kill prison0"));
                        if (!prison_isalive(pr)) {
                                /* Silently ignore already-dying prisons. */
                                flags &= ~PD_KILL;
                        } else {
                                if (!(flags & PD_DEREF)) {
                                        prison_hold(pr);
                                        flags |= PD_DEREF;
                                }
                                flags = prison_lock_xlock(pr, flags);
                                prison_deref_kill(pr, &freeprison);
                        }
                }
                if (flags & PD_DEUREF) {
                        /* Drop a user reference. */
                        KASSERT(refcount_load(&pr->pr_uref) > 0,
                            ("prison_deref PD_DEUREF on a dead prison (jid=%d)",
                             pr->pr_id));
                        if (!refcount_release_if_not_last(&pr->pr_uref)) {
                                if (!(flags & PD_DEREF)) {
                                        prison_hold(pr);
                                        flags |= PD_DEREF;
                                }
                                flags = prison_lock_xlock(pr, flags);
                                if (refcount_release(&pr->pr_uref) &&
                                    pr->pr_state == PRISON_STATE_ALIVE) {
                                        /*
                                         * When the last user references goes,
                                         * this becomes a dying prison.
                                         */
                                        KASSERT(
                                            refcount_load(&prison0.pr_uref) > 0,
                                            ("prison0 pr_uref=0"));
                                        pr->pr_state = PRISON_STATE_DYING;
                                        prison_cleanup_locked(pr);
                                        mtx_unlock(&pr->pr_mtx);
                                        flags &= ~PD_LOCKED;
                                        prison_cleanup_unlocked(pr);
                                }
                        }
                }
                if (flags & PD_KILL) {
                        /*
                         * Any remaining user references are probably processes
                         * that need to be killed, either in this prison or its
                         * descendants.
                         */
                        if (refcount_load(&pr->pr_uref) > 0)
                                killpr = pr;
                        /* Make sure the parent prison doesn't get killed. */
                        flags &= ~PD_KILL;
                }
                if (flags & PD_DEREF) {
                        /* Drop a reference. */
                        KASSERT(refcount_load(&pr->pr_ref) > 0,
                            ("prison_deref PD_DEREF on a dead prison (jid=%d)",
                             pr->pr_id));
                        if (!refcount_release_if_not_last(&pr->pr_ref)) {
                                flags = prison_lock_xlock(pr, flags);
                                if (refcount_release(&pr->pr_ref)) {
                                        /*
                                         * When the last reference goes,
                                         * unlink the prison and set it aside.
                                         */
                                        KASSERT(
                                            refcount_load(&pr->pr_uref) == 0,
                                            ("prison_deref: last ref, "
                                             "but still has %d urefs (jid=%d)",
                                             pr->pr_uref, pr->pr_id));
                                        KASSERT(
                                            refcount_load(&prison0.pr_ref) != 0,
                                            ("prison0 pr_ref=0"));
#ifdef MAC
                                        /*
                                         * The MAC framework will call into any
                                         * policies that want to hook
                                         * prison_destroy_label, so ideally we
                                         * call this prior to any final state
                                         * invalidation to be safe.
                                         */
                                        mac_prison_destroy(pr);
#endif
                                        pr->pr_state = PRISON_STATE_INVALID;
                                        TAILQ_REMOVE(&allprison, pr, pr_list);
                                        LIST_REMOVE(pr, pr_sibling);
                                        TAILQ_INSERT_TAIL(&freeprison, pr,
                                            pr_list);
                                        for (ppr = pr->pr_parent;
                                             ppr != NULL;
                                             ppr = ppr->pr_parent)
                                                ppr->pr_childcount--;
                                        /*
                                         * Removing a prison frees references
                                         * from its parent.
                                         */
                                        ppr = pr->pr_parent;
                                        pr->pr_parent = NULL;
                                        mtx_unlock(&pr->pr_mtx);

                                        pr = ppr;
                                        flags &= ~PD_LOCKED;
                                        flags |= PD_DEREF | PD_DEUREF;
                                        continue;
                                }
                        }
                }
                break;
        }

        /* Release all the prison locks. */
        if (flags & PD_LOCKED)
                mtx_unlock(&pr->pr_mtx);
        if (flags & PD_LIST_SLOCKED)
                sx_sunlock(&allprison_lock);
        else if (flags & PD_LIST_XLOCKED)
                sx_xunlock(&allprison_lock);

        /* Kill any processes attached to a killed prison. */
        if (killpr != NULL)
                prison_proc_iterate(killpr, prison_kill_processes_cb, NULL);

        /*
         * Finish removing any unreferenced prisons, which couldn't happen
         * while allprison_lock was held (to avoid a LOR on vrele).
         */
        TAILQ_FOREACH_SAFE(rpr, &freeprison, pr_list, tpr) {
#ifdef VIMAGE
                if (rpr->pr_flags & PR_VNET)
                        vnet_destroy(rpr->pr_vnet);
#endif
                if (rpr->pr_root != NULL)
                        vrele(rpr->pr_root);
                mtx_destroy(&rpr->pr_mtx);
#ifdef INET
                prison_ip_free(rpr->pr_addrs[PR_INET]);
#endif
#ifdef INET6
                prison_ip_free(rpr->pr_addrs[PR_INET6]);
#endif
                if (rpr->pr_cpuset != NULL)
                        cpuset_rel(rpr->pr_cpuset);
                osd_jail_exit(rpr);
#ifdef RACCT
                if (racct_enable)
                        prison_racct_detach(rpr);
#endif
                TAILQ_REMOVE(&freeprison, rpr, pr_list);
                free(rpr, M_PRISON);
        }
}

/*
 * Kill the prison and its descendants.  Mark them as dying, clear the
 * persist flag, and call module remove methods.
 */
static void
prison_deref_kill(struct prison *pr, struct prisonlist *freeprison)
{
        struct prison *cpr, *ppr, *rpr;
        bool descend;

        /*
         * Unlike the descendants, the target prison can be killed
         * even if it is currently dying.  This is useful for failed
         * creation in jail_set(2).
         */
        KASSERT(refcount_load(&pr->pr_ref) > 0,
            ("Trying to kill dead prison %p (jid=%d).",
             pr, pr->pr_id));
        refcount_acquire(&pr->pr_uref);
        pr->pr_state = PRISON_STATE_DYING;
        mtx_unlock(&pr->pr_mtx);

        rpr = NULL;
        FOREACH_PRISON_DESCENDANT_PRE_POST(pr, cpr, descend) {
                if (descend) {
                        if (!prison_isalive(cpr)) {
                                descend = false;
                                continue;
                        }
                        prison_hold(cpr);
                        prison_proc_hold(cpr);
                        mtx_lock(&cpr->pr_mtx);
                        cpr->pr_state = PRISON_STATE_DYING;
                        cpr->pr_flags |= PR_REMOVE;
                        mtx_unlock(&cpr->pr_mtx);
                        continue;
                }
                if (!(cpr->pr_flags & PR_REMOVE))
                        continue;
                prison_cleanup_unlocked(cpr);
                mtx_lock(&cpr->pr_mtx);
                prison_cleanup_locked(cpr);
                cpr->pr_flags &= ~PR_REMOVE;
                if (cpr->pr_flags & PR_PERSIST) {
                        cpr->pr_flags &= ~PR_PERSIST;
                        prison_proc_free_not_last(cpr);
                        prison_free_not_last(cpr);
                }
                (void)refcount_release(&cpr->pr_uref);
                if (refcount_release(&cpr->pr_ref)) {
                        /*
                         * When the last reference goes, unlink the prison
                         * and set it aside for prison_deref() to handle.
                         * Delay unlinking the sibling list to keep the loop
                         * safe.
                         */
                        if (rpr != NULL)
                                LIST_REMOVE(rpr, pr_sibling);
                        rpr = cpr;
                        rpr->pr_state = PRISON_STATE_INVALID;
                        TAILQ_REMOVE(&allprison, rpr, pr_list);
                        TAILQ_INSERT_TAIL(freeprison, rpr, pr_list);
                        /*
                         * Removing a prison frees references from its parent.
                         */
                        ppr = rpr->pr_parent;
                        prison_proc_free_not_last(ppr);
                        prison_free_not_last(ppr);
                        for (; ppr != NULL; ppr = ppr->pr_parent)
                                ppr->pr_childcount--;
                }
                mtx_unlock(&cpr->pr_mtx);
        }
        if (rpr != NULL)
                LIST_REMOVE(rpr, pr_sibling);

        prison_cleanup_unlocked(pr);
        mtx_lock(&pr->pr_mtx);
        prison_cleanup_locked(pr);
        if (pr->pr_flags & PR_PERSIST) {
                pr->pr_flags &= ~PR_PERSIST;
                prison_proc_free_not_last(pr);
                prison_free_not_last(pr);
        }
        (void)refcount_release(&pr->pr_uref);
}

/*
 * Given the current locking state in the flags, make sure allprison_lock
 * is held exclusive, and the prison is locked.  Return flags indicating
 * the new state.
 */
static int
prison_lock_xlock(struct prison *pr, int flags)
{

        if (!(flags & PD_LIST_XLOCKED)) {
                /*
                 * Get allprison_lock, which may be an upgrade,
                 * and may require unlocking the prison.
                 */
                if (flags & PD_LOCKED) {
                        mtx_unlock(&pr->pr_mtx);
                        flags &= ~PD_LOCKED;
                }
                if (flags & PD_LIST_SLOCKED) {
                        if (!sx_try_upgrade(&allprison_lock)) {
                                sx_sunlock(&allprison_lock);
                                sx_xlock(&allprison_lock);
                        }
                        flags &= ~PD_LIST_SLOCKED;
                } else
                        sx_xlock(&allprison_lock);
                flags |= PD_LIST_XLOCKED;
        }
        if (!(flags & PD_LOCKED)) {
                /* Lock the prison mutex. */
                mtx_lock(&pr->pr_mtx);
                flags |= PD_LOCKED;
        }
        return flags;
}

/*
 * Release a prison's resources when it starts dying (when the last user
 * reference is dropped, or when it is killed).  Two functions are called,
 * for work that requires a locked prison or an unlocked one.
 */
static void
prison_cleanup_locked(struct prison *pr)
{
        sx_assert(&allprison_lock, SA_XLOCKED);
        mtx_assert(&pr->pr_mtx, MA_OWNED);
        prison_knote(pr, NOTE_JAIL_REMOVE);
        knlist_detach(pr->pr_klist);
        jaildesc_prison_cleanup(pr);
        pr->pr_klist = NULL;
}

static void
prison_cleanup_unlocked(struct prison *pr)
{
        sx_assert(&allprison_lock, SA_XLOCKED);
        mtx_assert(&pr->pr_mtx, MA_NOTOWNED);
        vfs_exjail_delete(pr);
        shm_remove_prison(pr);
        (void)osd_jail_call(pr, PR_METHOD_REMOVE, NULL);
}

/*
 * Set or clear a permission bit in the pr_allow field, passing restrictions
 * (cleared permission) down to child jails.
 */
void
prison_set_allow(struct ucred *cred, unsigned flag, int enable)
{
        struct prison *pr;

        pr = cred->cr_prison;
        sx_slock(&allprison_lock);
        mtx_lock(&pr->pr_mtx);
        prison_set_allow_locked(pr, flag, enable);
        mtx_unlock(&pr->pr_mtx);
        sx_sunlock(&allprison_lock);
}

static void
prison_set_allow_locked(struct prison *pr, unsigned flag, int enable)
{
        struct prison *cpr;
        int descend;

        if (enable != 0)
                pr->pr_allow |= flag;
        else {
                pr->pr_allow &= ~flag;
                FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
                        cpr->pr_allow &= ~flag;
        }
}

/*
 * Check if a jail supports the given address family.
 *
 * Returns 0 if not jailed or the address family is supported, EAFNOSUPPORT
 * if not.
 */
int
prison_check_af(struct ucred *cred, int af)
{
        struct prison *pr;
        int error;

        KASSERT(cred != NULL, ("%s: cred is NULL", __func__));

        pr = cred->cr_prison;
#ifdef VIMAGE
        /* Prisons with their own network stack are not limited. */
        if (prison_owns_vnet(pr))
                return (0);
#endif

        error = 0;
        switch (af)
        {
#ifdef INET
        case AF_INET:
                if (pr->pr_flags & PR_IP4)
                {
                        mtx_lock(&pr->pr_mtx);
                        if ((pr->pr_flags & PR_IP4) &&
                            pr->pr_addrs[PR_INET] == NULL)
                                error = EAFNOSUPPORT;
                        mtx_unlock(&pr->pr_mtx);
                }
                break;
#endif
#ifdef INET6
        case AF_INET6:
                if (pr->pr_flags & PR_IP6)
                {
                        mtx_lock(&pr->pr_mtx);
                        if ((pr->pr_flags & PR_IP6) &&
                            pr->pr_addrs[PR_INET6] == NULL)
                                error = EAFNOSUPPORT;
                        mtx_unlock(&pr->pr_mtx);
                }
                break;
#endif
        case AF_LOCAL:
        case AF_ROUTE:
        case AF_NETLINK:
                break;
        default:
                if (!(pr->pr_allow & PR_ALLOW_SOCKET_AF))
                        error = EAFNOSUPPORT;
        }
        return (error);
}

/*
 * Check if given address belongs to the jail referenced by cred (wrapper to
 * prison_check_ip[46]).
 *
 * Returns 0 if jail doesn't restrict the address family or if address belongs
 * to jail, EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if
 * the jail doesn't allow the address family.  IPv4 Address passed in in NBO.
 */
int
prison_if(struct ucred *cred, const struct sockaddr *sa)
{
#ifdef INET
        const struct sockaddr_in *sai;
#endif
#ifdef INET6
        const struct sockaddr_in6 *sai6;
#endif
        int error;

        KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
        KASSERT(sa != NULL, ("%s: sa is NULL", __func__));

#ifdef VIMAGE
        if (prison_owns_vnet(cred->cr_prison))
                return (0);
#endif

        error = 0;
        switch (sa->sa_family)
        {
#ifdef INET
        case AF_INET:
                sai = (const struct sockaddr_in *)sa;
                error = prison_check_ip4(cred, &sai->sin_addr);
                break;
#endif
#ifdef INET6
        case AF_INET6:
                sai6 = (const struct sockaddr_in6 *)sa;
                error = prison_check_ip6(cred, &sai6->sin6_addr);
                break;
#endif
        default:
                if (!(cred->cr_prison->pr_allow & PR_ALLOW_SOCKET_AF))
                        error = EAFNOSUPPORT;
        }
        return (error);
}

/*
 * Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
 */
int
prison_check(struct ucred *cred1, struct ucred *cred2)
{

        return ((cred1->cr_prison == cred2->cr_prison ||
            prison_ischild(cred1->cr_prison, cred2->cr_prison)) ? 0 : ESRCH);
}

/*
 * For mountd/nfsd to run within a prison, it must be:
 * - A vnet prison.
 * - PR_ALLOW_NFSD must be set on it.
 * - The root directory (pr_root) of the prison must be
 *   a file system mount point, so the mountd can hang
 *   export information on it.
 * - The prison's enforce_statfs cannot be 0, so that
 *   mountd(8) can do exports.
 */
bool
prison_check_nfsd(struct ucred *cred)
{

        if (jailed_without_vnet(cred))
                return (false);
        if (!prison_allow(cred, PR_ALLOW_NFSD))
                return (false);
        if ((cred->cr_prison->pr_root->v_vflag & VV_ROOT) == 0)
                return (false);
        if (cred->cr_prison->pr_enforce_statfs == 0)
                return (false);
        return (true);
}

/*
 * Return true if p2 is a child of p1, otherwise false.
 */
bool
prison_ischild(struct prison *pr1, struct prison *pr2)
{

        for (pr2 = pr2->pr_parent; pr2 != NULL; pr2 = pr2->pr_parent)
                if (pr1 == pr2)
                        return (true);
        return (false);
}

/*
 * Return true if the prison is currently alive.  A prison is alive if it
 * holds user references and it isn't being removed.
 */
bool
prison_isalive(const struct prison *pr)
{

        if (__predict_false(pr->pr_state != PRISON_STATE_ALIVE))
                return (false);
        return (true);
}

/*
 * Return true if the prison is currently valid.  A prison is valid if it has
 * been fully created, and is not being destroyed.  Note that dying prisons
 * are still considered valid.  Invalid prisons won't be found under normal
 * circumstances, as they're only put in that state by functions that have
 * an exclusive hold on allprison_lock.
 */
bool
prison_isvalid(struct prison *pr)
{

        if (__predict_false(pr->pr_state == PRISON_STATE_INVALID))
                return (false);
        if (__predict_false(refcount_load(&pr->pr_ref) == 0))
                return (false);
        return (true);
}

/*
 * Return true if the passed credential is in a jail and that jail does not
 * have its own virtual network stack, otherwise false.
 */
bool
jailed_without_vnet(struct ucred *cred)
{

        if (!jailed(cred))
                return (false);
#ifdef VIMAGE
        if (prison_owns_vnet(cred->cr_prison))
                return (false);
#endif

        return (true);
}

/*
 * Return the correct hostname (domainname, et al) for the passed credential.
 */
void
getcredhostname(struct ucred *cred, char *buf, size_t size)
{
        struct prison *pr;

        /*
         * A NULL credential can be used to shortcut to the physical
         * system's hostname.
         */
        pr = (cred != NULL) ? cred->cr_prison : &prison0;
        mtx_lock(&pr->pr_mtx);
        strlcpy(buf, pr->pr_hostname, size);
        mtx_unlock(&pr->pr_mtx);
}

void
getcreddomainname(struct ucred *cred, char *buf, size_t size)
{

        mtx_lock(&cred->cr_prison->pr_mtx);
        strlcpy(buf, cred->cr_prison->pr_domainname, size);
        mtx_unlock(&cred->cr_prison->pr_mtx);
}

void
getcredhostuuid(struct ucred *cred, char *buf, size_t size)
{

        mtx_lock(&cred->cr_prison->pr_mtx);
        strlcpy(buf, cred->cr_prison->pr_hostuuid, size);
        mtx_unlock(&cred->cr_prison->pr_mtx);
}

void
getcredhostid(struct ucred *cred, unsigned long *hostid)
{

        mtx_lock(&cred->cr_prison->pr_mtx);
        *hostid = cred->cr_prison->pr_hostid;
        mtx_unlock(&cred->cr_prison->pr_mtx);
}

void
getjailname(struct ucred *cred, char *name, size_t len)
{

        mtx_lock(&cred->cr_prison->pr_mtx);
        strlcpy(name, cred->cr_prison->pr_name, len);
        mtx_unlock(&cred->cr_prison->pr_mtx);
}

#ifdef VIMAGE
/*
 * Determine whether the prison owns its VNET.
 */
bool
prison_owns_vnet(struct prison *pr)
{

        /*
         * vnets cannot be added/removed after jail creation,
         * so no need to lock here.
         */
        return ((pr->pr_flags & PR_VNET) != 0);
}
#endif

/*
 * Determine whether the subject represented by cred can "see"
 * status of a mount point.
 * Returns: 0 for permitted, ENOENT otherwise.
 * XXX: This function should be called cr_canseemount() and should be
 *      placed in kern_prot.c.
 */
int
prison_canseemount(struct ucred *cred, struct mount *mp)
{
        struct prison *pr;
        struct statfs *sp;
        size_t len;

        pr = cred->cr_prison;
        if (pr->pr_enforce_statfs == 0)
                return (0);
        if (pr->pr_root->v_mount == mp)
                return (0);
        if (pr->pr_enforce_statfs == 2)
                return (ENOENT);
        /*
         * If jail's chroot directory is set to "/" we should be able to see
         * all mount-points from inside a jail.
         * This is ugly check, but this is the only situation when jail's
         * directory ends with '/'.
         */
        if (strcmp(pr->pr_path, "/") == 0)
                return (0);
        len = strlen(pr->pr_path);
        sp = &mp->mnt_stat;
        if (strncmp(pr->pr_path, sp->f_mntonname, len) != 0)
                return (ENOENT);
        /*
         * Be sure that we don't have situation where jail's root directory
         * is "/some/path" and mount point is "/some/pathpath".
         */
        if (sp->f_mntonname[len] != '\0' && sp->f_mntonname[len] != '/')
                return (ENOENT);
        return (0);
}

void
prison_enforce_statfs(struct ucred *cred, struct mount *mp, struct statfs *sp)
{
        char jpath[MAXPATHLEN];
        struct prison *pr;
        size_t len;

        pr = cred->cr_prison;
        if (pr->pr_enforce_statfs == 0)
                return;
        if (prison_canseemount(cred, mp) != 0) {
                bzero(&sp->f_fsid, sizeof(sp->f_fsid));
                bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
                strlcpy(sp->f_mntonname, "[restricted]",
                    sizeof(sp->f_mntonname));
                return;
        }
        if (pr->pr_enforce_statfs > 1)
                bzero(&sp->f_fsid, sizeof(sp->f_fsid));
        if (pr->pr_root->v_mount == mp) {
                /*
                 * Clear current buffer data, so we are sure nothing from
                 * the valid path left there.
                 */
                bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
                *sp->f_mntonname = '/';
                return;
        }
        /*
         * If jail's chroot directory is set to "/" we should be able to see
         * all mount-points from inside a jail.
         */
        if (strcmp(pr->pr_path, "/") == 0)
                return;
        len = strlen(pr->pr_path);
        strlcpy(jpath, sp->f_mntonname + len, sizeof(jpath));
        /*
         * Clear current buffer data, so we are sure nothing from
         * the valid path left there.
         */
        bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
        if (*jpath == '\0') {
                /* Should never happen. */
                *sp->f_mntonname = '/';
        } else {
                strlcpy(sp->f_mntonname, jpath, sizeof(sp->f_mntonname));
        }
}

/*
 * Check with permission for a specific privilege is granted within jail.  We
 * have a specific list of accepted privileges; the rest are denied.
 */
int
prison_priv_check(struct ucred *cred, int priv)
{
        struct prison *pr;
        int error;

        /*
         * Some policies have custom handlers. This routine should not be
         * called for them. See priv_check_cred().
         */
        switch (priv) {
        case PRIV_VFS_LOOKUP:
        case PRIV_VFS_GENERATION:
                KASSERT(0, ("prison_priv_check instead of a custom handler "
                    "called for %d\n", priv));
        }

        if (!jailed(cred))
                return (0);

#ifdef VIMAGE
        /*
         * Privileges specific to prisons with a virtual network stack.
         * There might be a duplicate entry here in case the privilege
         * is only granted conditionally in the legacy jail case.
         */
        switch (priv) {
                /*
                 * NFS-specific privileges.
                 */
        case PRIV_NFS_DAEMON:
        case PRIV_VFS_GETFH:
        case PRIV_VFS_MOUNT_EXPORTED:
                if (!prison_check_nfsd(cred))
                        return (EPERM);
#ifdef notyet
        case PRIV_NFS_LOCKD:
#endif
                /*
                 * Network stack privileges.
                 */
        case PRIV_NET_BRIDGE:
        case PRIV_NET_GRE:
        case PRIV_NET_BPF:
        case PRIV_NET_RAW:              /* Dup, cond. in legacy jail case. */
        case PRIV_NET_ROUTE:
        case PRIV_NET_TAP:
        case PRIV_NET_SETIFMTU:
        case PRIV_NET_SETIFFLAGS:
        case PRIV_NET_SETIFCAP:
        case PRIV_NET_SETIFDESCR:
        case PRIV_NET_SETIFNAME :
        case PRIV_NET_SETIFMETRIC:
        case PRIV_NET_SETIFPHYS:
        case PRIV_NET_SETIFMAC:
        case PRIV_NET_SETLANPCP:
        case PRIV_NET_ADDMULTI:
        case PRIV_NET_DELMULTI:
        case PRIV_NET_HWIOCTL:
        case PRIV_NET_SETLLADDR:
        case PRIV_NET_ADDIFGROUP:
        case PRIV_NET_DELIFGROUP:
        case PRIV_NET_IFCREATE:
        case PRIV_NET_IFDESTROY:
        case PRIV_NET_ADDIFADDR:
        case PRIV_NET_DELIFADDR:
        case PRIV_NET_LAGG:
        case PRIV_NET_GIF:
        case PRIV_NET_SETIFVNET:
        case PRIV_NET_SETIFFIB:
        case PRIV_NET_OVPN:
        case PRIV_NET_GENEVE:
        case PRIV_NET_ME:
        case PRIV_NET_WG:

                /*
                 * 802.11-related privileges.
                 */
        case PRIV_NET80211_VAP_GETKEY:
        case PRIV_NET80211_VAP_MANAGE:

#ifdef notyet
                /*
                 * ATM privileges.
                 */
        case PRIV_NETATM_CFG:
        case PRIV_NETATM_ADD:
        case PRIV_NETATM_DEL:
        case PRIV_NETATM_SET:

                /*
                 * Bluetooth privileges.
                 */
        case PRIV_NETBLUETOOTH_RAW:
#endif

                /*
                 * Netgraph and netgraph module privileges.
                 */
        case PRIV_NETGRAPH_CONTROL:
#ifdef notyet
        case PRIV_NETGRAPH_TTY:
#endif

                /*
                 * IPv4 and IPv6 privileges.
                 */
        case PRIV_NETINET_IPFW:
        case PRIV_NETINET_DIVERT:
        case PRIV_NETINET_PF:
        case PRIV_NETINET_DUMMYNET:
        case PRIV_NETINET_CARP:
        case PRIV_NETINET_MROUTE:
        case PRIV_NETINET_RAW:
        case PRIV_NETINET_ADDRCTRL6:
        case PRIV_NETINET_ND6:
        case PRIV_NETINET_SCOPE6:
        case PRIV_NETINET_ALIFETIME6:
        case PRIV_NETINET_IPSEC:
        case PRIV_NETINET_BINDANY:

#ifdef notyet
                /*
                 * NCP privileges.
                 */
        case PRIV_NETNCP:

                /*
                 * SMB privileges.
                 */
        case PRIV_NETSMB:
#endif

        /*
         * No default: or deny here.
         * In case of no permit fall through to next switch().
         */
                if (cred->cr_prison->pr_flags & PR_VNET)
                        return (0);
        }
#endif /* VIMAGE */

        switch (priv) {
                /*
                 * Allow ktrace privileges for root in jail.
                 */
        case PRIV_KTRACE:
                return (0);

                /*
                 * Allow jailed processes to configure audit identity and
                 * submit audit records (login, etc).  In the future we may
                 * want to further refine the relationship between audit and
                 * jail.
                 */
        case PRIV_AUDIT_GETAUDIT:
        case PRIV_AUDIT_SETAUDIT:
                if (cred->cr_prison->pr_allow & PR_ALLOW_SETAUDIT)
                        return (0);
                else
                        return (EPERM);
#if 0
        case PRIV_AUDIT_SUBMIT:
#endif

                /*
                 * Allow jailed processes to manipulate process UNIX
                 * credentials in any way they see fit.
                 */
        case PRIV_CRED_SETCRED:
        case PRIV_CRED_SETUID:
        case PRIV_CRED_SETEUID:
        case PRIV_CRED_SETGID:
        case PRIV_CRED_SETEGID:
        case PRIV_CRED_SETGROUPS:
        case PRIV_CRED_SETREUID:
        case PRIV_CRED_SETREGID:
        case PRIV_CRED_SETRESUID:
        case PRIV_CRED_SETRESGID:

                /*
                 * Jail implements visibility constraints already, so allow
                 * jailed root to override uid/gid-based constraints.
                 */
        case PRIV_SEEOTHERGIDS:
        case PRIV_SEEOTHERUIDS:
        case PRIV_SEEJAILPROC:

                /*
                 * Jail implements inter-process debugging limits already, so
                 * allow jailed root various debugging privileges.
                 */
        case PRIV_DEBUG_DIFFCRED:
        case PRIV_DEBUG_SUGID:
        case PRIV_DEBUG_UNPRIV:
        case PRIV_DEBUG_DIFFJAIL:

                /*
                 * Allow jail to set various resource limits and login
                 * properties, and for now, exceed process resource limits.
                 */
        case PRIV_PROC_LIMIT:
        case PRIV_PROC_SETLOGIN:
        case PRIV_PROC_SETRLIMIT:

                /*
                 * Debuggers should work in jails.
                 */
        case PRIV_PROC_MEM_WRITE:

                /*
                 * System V and POSIX IPC privileges are granted in jail.
                 */
        case PRIV_IPC_READ:
        case PRIV_IPC_WRITE:
        case PRIV_IPC_ADMIN:
        case PRIV_IPC_MSGSIZE:
        case PRIV_MQ_ADMIN:

                /*
                 * Jail operations within a jail work on child jails.
                 */
        case PRIV_JAIL_ATTACH:
        case PRIV_JAIL_SET:
        case PRIV_JAIL_REMOVE:

                /*
                 * Jail implements its own inter-process limits, so allow
                 * root processes in jail to change scheduling on other
                 * processes in the same jail.  Likewise for signalling.
                 */
        case PRIV_SCHED_DIFFCRED:
        case PRIV_SCHED_CPUSET:
        case PRIV_SCHED_DIFFJAIL:
        case PRIV_SIGNAL_DIFFCRED:
        case PRIV_SIGNAL_SUGID:
        case PRIV_SIGNAL_DIFFJAIL:

                /*
                 * Allow jailed processes to write to sysctls marked as jail
                 * writable.
                 */
        case PRIV_SYSCTL_WRITEJAIL:

                /*
                 * Allow root in jail to manage a variety of quota
                 * properties.  These should likely be conditional on a
                 * configuration option.
                 */
        case PRIV_VFS_GETQUOTA:
        case PRIV_VFS_SETQUOTA:

                /*
                 * Since Jail relies on chroot() to implement file system
                 * protections, grant many VFS privileges to root in jail.
                 * Be careful to exclude mount-related and NFS-related
                 * privileges.
                 */
        case PRIV_VFS_READ:
        case PRIV_VFS_WRITE:
        case PRIV_VFS_ADMIN:
        case PRIV_VFS_EXEC:
        case PRIV_VFS_BLOCKRESERVE:     /* XXXRW: Slightly surprising. */
        case PRIV_VFS_CHFLAGS_DEV:
        case PRIV_VFS_CHOWN:
        case PRIV_VFS_CHROOT:
        case PRIV_VFS_RETAINSUGID:
        case PRIV_VFS_FCHROOT:
        case PRIV_VFS_LINK:
        case PRIV_VFS_SETGID:
        case PRIV_VFS_STAT:
        case PRIV_VFS_STICKYFILE:

                /*
                 * As in the non-jail case, non-root users are expected to be
                 * able to read kernel/physical memory (provided /dev/[k]mem
                 * exists in the jail and they have permission to access it).
                 */
        case PRIV_KMEM_READ:
                return (0);

                /*
                 * Depending on the global setting, allow privilege of
                 * setting system flags.
                 */
        case PRIV_VFS_SYSFLAGS:
                if (cred->cr_prison->pr_allow & PR_ALLOW_CHFLAGS)
                        return (0);
                else
                        return (EPERM);

                /*
                 * Depending on the global setting, allow privilege of
                 * mounting/unmounting file systems.
                 */
        case PRIV_VFS_MOUNT:
        case PRIV_VFS_UNMOUNT:
        case PRIV_VFS_MOUNT_NONUSER:
        case PRIV_VFS_MOUNT_OWNER:
                pr = cred->cr_prison;
                prison_lock(pr);
                if (pr->pr_allow & PR_ALLOW_MOUNT && pr->pr_enforce_statfs < 2)
                        error = 0;
                else
                        error = EPERM;
                prison_unlock(pr);
                return (error);

                /*
                 * Jails should hold no disposition on the PRIV_VFS_READ_DIR
                 * policy.  priv_check_cred will not specifically allow it, and
                 * we may want a MAC policy to allow it.
                 */
        case PRIV_VFS_READ_DIR:
                return (0);

                /*
                 * Conditionally allow privileged process in the jail to
                 * manipulate filesystem extended attributes in the system
                 * namespace.
                 */
        case PRIV_VFS_EXTATTR_SYSTEM:
                if ((cred->cr_prison->pr_allow & PR_ALLOW_EXTATTR) != 0)
                        return (0);
                else
                        return (EPERM);

                /*
                 * Conditionnaly allow locking (unlocking) physical pages
                 * in memory.
                 */
        case PRIV_VM_MLOCK:
        case PRIV_VM_MUNLOCK:
                if (cred->cr_prison->pr_allow & PR_ALLOW_MLOCK)
                        return (0);
                else
                        return (EPERM);

                /*
                 * Conditionally allow jailed root to bind reserved ports.
                 */
        case PRIV_NETINET_RESERVEDPORT:
                if (cred->cr_prison->pr_allow & PR_ALLOW_RESERVED_PORTS)
                        return (0);
                else
                        return (EPERM);

                /*
                 * Allow jailed root to reuse in-use ports.
                 */
        case PRIV_NETINET_REUSEPORT:
                return (0);

                /*
                 * Allow jailed root to set certain IPv4/6 (option) headers.
                 */
        case PRIV_NETINET_SETHDROPTS:
                return (0);

                /*
                 * Conditionally allow creating raw sockets in jail.
                 */
        case PRIV_NETINET_RAW:
                if (cred->cr_prison->pr_allow & PR_ALLOW_RAW_SOCKETS)
                        return (0);
                else
                        return (EPERM);

                /*
                 * Since jail implements its own visibility limits on netstat
                 * sysctls, allow getcred.  This allows identd to work in
                 * jail.
                 */
        case PRIV_NETINET_GETCRED:
                return (0);

                /*
                 * Allow jailed root to set loginclass.
                 */
        case PRIV_PROC_SETLOGINCLASS:
                return (0);

                /*
                 * Do not allow a process inside a jail to read the kernel
                 * message buffer unless explicitly permitted.
                 */
        case PRIV_MSGBUF:
                if (cred->cr_prison->pr_allow & PR_ALLOW_READ_MSGBUF)
                        return (0);
                return (EPERM);

                /*
                 * Conditionally allow privileged process in the jail adjust
                 * machine time.
                 */
        case PRIV_ADJTIME:
        case PRIV_NTP_ADJTIME:
                if (cred->cr_prison->pr_allow &
                    (PR_ALLOW_ADJTIME | PR_ALLOW_SETTIME)) {
                        return (0);
                }
                return (EPERM);

                /*
                 * Conditionally allow privileged process in the jail set
                 * machine time.
                 */
        case PRIV_SETTIMEOFDAY:
        case PRIV_CLOCK_SETTIME:
                if (cred->cr_prison->pr_allow & PR_ALLOW_SETTIME)
                        return (0);
                else
                        return (EPERM);

                /*
                 * Conditionally allow privileged process in the jail to modify
                 * the routing table.
                 */
        case PRIV_NET_ROUTE:
                if (cred->cr_prison->pr_allow & PR_ALLOW_ROUTING)
                        return (0);
                else
                        return (EPERM);

        case PRIV_VMM_CREATE:
        case PRIV_VMM_DESTROY:
                /*
                 * Jailed root can create and destroy VMs; the vmm module
                 * additionally checks for the allow.vmm flag.
                 */
                return (0);

        case PRIV_VMM_PPTDEV:
                /*
                 * Allow jailed root to manage passthrough devices.  vmm(4) also
                 * checks for the dynamically added allow.vmm_ppt.
                 */
                return (0);

        default:
                /*
                 * In all remaining cases, deny the privilege request.  This
                 * includes almost all network privileges, many system
                 * configuration privileges.
                 */
                return (EPERM);
        }
}

/*
 * Return the part of pr2's name that is relative to pr1, or the whole name
 * if it does not directly follow.
 */

char *
prison_name(struct prison *pr1, struct prison *pr2)
{
        char *name;

        /* Jails see themselves as "0" (if they see themselves at all). */
        if (pr1 == pr2)
                return "0";
        name = pr2->pr_name;
        if (prison_ischild(pr1, pr2)) {
                /*
                 * pr1 isn't locked (and allprison_lock may not be either)
                 * so its length can't be counted on.  But the number of dots
                 * can be counted on - and counted.
                 */
                for (; pr1 != &prison0; pr1 = pr1->pr_parent)
                        name = strchr(name, '.') + 1;
        }
        return (name);
}

/*
 * Return the part of pr2's path that is relative to pr1, or the whole path
 * if it does not directly follow.
 */
static char *
prison_path(struct prison *pr1, struct prison *pr2)
{
        char *path1, *path2;
        int len1;

        path1 = pr1->pr_path;
        path2 = pr2->pr_path;
        if (!strcmp(path1, "/"))
                return (path2);
        len1 = strlen(path1);
        if (strncmp(path1, path2, len1))
                return (path2);
        if (path2[len1] == '\0')
                return "/";
        if (path2[len1] == '/')
                return (path2 + len1);
        return (path2);
}

/*
 * Jail-related sysctls.
 */
SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Jails");

#if defined(INET) || defined(INET6)
/*
 * Copy address array to memory that would be then SYSCTL_OUT-ed.
 * sysctl_jail_list() helper.
 */
static void
prison_ip_copyout(struct prison *pr, const pr_family_t af, void **out, int *len)
{
        const struct prison_ip *pip;
        const size_t size = pr_families[af].size;

 again:
        mtx_assert(&pr->pr_mtx, MA_OWNED);
        if ((pip = pr->pr_addrs[af]) != NULL) {
                if (*len < pip->ips) {
                        *len = pip->ips;
                        mtx_unlock(&pr->pr_mtx);
                        *out = realloc(*out, *len * size, M_TEMP, M_WAITOK);
                        mtx_lock(&pr->pr_mtx);
                        goto again;
                }
                bcopy(pip->pr_ip, *out, pip->ips * size);
        }
}
#endif

static int
sysctl_jail_list(SYSCTL_HANDLER_ARGS)
{
        struct xprison *xp;
        struct prison *pr, *cpr;
#ifdef INET
        struct in_addr *ip4 = NULL;
        int ip4s = 0;
#endif
#ifdef INET6
        struct in6_addr *ip6 = NULL;
        int ip6s = 0;
#endif
        int descend, error;

        xp = malloc(sizeof(*xp), M_TEMP, M_WAITOK);
        pr = req->td->td_ucred->cr_prison;
        error = 0;
        sx_slock(&allprison_lock);
        FOREACH_PRISON_DESCENDANT(pr, cpr, descend) {
                mtx_lock(&cpr->pr_mtx);
#ifdef INET
                prison_ip_copyout(cpr, PR_INET, (void **)&ip4, &ip4s);
#endif
#ifdef INET6
                prison_ip_copyout(cpr, PR_INET6, (void **)&ip6, &ip6s);
#endif
                bzero(xp, sizeof(*xp));
                xp->pr_version = XPRISON_VERSION;
                xp->pr_id = cpr->pr_id;
                xp->pr_state = cpr->pr_state;
                strlcpy(xp->pr_path, prison_path(pr, cpr), sizeof(xp->pr_path));
                strlcpy(xp->pr_host, cpr->pr_hostname, sizeof(xp->pr_host));
                strlcpy(xp->pr_name, prison_name(pr, cpr), sizeof(xp->pr_name));
#ifdef INET
                xp->pr_ip4s = ip4s;
#endif
#ifdef INET6
                xp->pr_ip6s = ip6s;
#endif
                mtx_unlock(&cpr->pr_mtx);
                error = SYSCTL_OUT(req, xp, sizeof(*xp));
                if (error)
                        break;
#ifdef INET
                if (xp->pr_ip4s > 0) {
                        error = SYSCTL_OUT(req, ip4,
                            xp->pr_ip4s * sizeof(struct in_addr));
                        if (error)
                                break;
                }
#endif
#ifdef INET6
                if (xp->pr_ip6s > 0) {
                        error = SYSCTL_OUT(req, ip6,
                            xp->pr_ip6s * sizeof(struct in6_addr));
                        if (error)
                                break;
                }
#endif
        }
        sx_sunlock(&allprison_lock);
        free(xp, M_TEMP);
#ifdef INET
        free(ip4, M_TEMP);
#endif
#ifdef INET6
        free(ip6, M_TEMP);
#endif
        return (error);
}

SYSCTL_OID(_security_jail, OID_AUTO, list,
    CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_jail_list, "S", "List of active jails");

static int
sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
{
        int error, injail;

        injail = jailed(req->td->td_ucred);
        error = SYSCTL_OUT(req, &injail, sizeof(injail));

        return (error);
}

SYSCTL_PROC(_security_jail, OID_AUTO, jailed,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_jail_jailed, "I", "Process in jail?");

static int
sysctl_jail_vnet(SYSCTL_HANDLER_ARGS)
{
        int error, havevnet;
#ifdef VIMAGE
        struct ucred *cred = req->td->td_ucred;

        havevnet = jailed(cred) && prison_owns_vnet(cred->cr_prison);
#else
        havevnet = 0;
#endif
        error = SYSCTL_OUT(req, &havevnet, sizeof(havevnet));

        return (error);
}

SYSCTL_PROC(_security_jail, OID_AUTO, vnet,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_jail_vnet, "I", "Jail owns vnet?");

#if defined(INET) || defined(INET6)
SYSCTL_UINT(_security_jail, OID_AUTO, jail_max_af_ips, CTLFLAG_RW,
    &jail_max_af_ips, 0,
    "Number of IP addresses a jail may have at most per address family (deprecated)");
#endif

/*
 * Default parameters for jail(2) compatibility.  For historical reasons,
 * the sysctl names have varying similarity to the parameter names.  Prisons
 * just see their own parameters, and can't change them.
 */
static int
sysctl_jail_default_allow(SYSCTL_HANDLER_ARGS)
{
        int error, i;

        /* Get the current flag value, and convert it to a boolean. */
        if (req->td->td_ucred->cr_prison == &prison0) {
                mtx_lock(&prison0.pr_mtx);
                i = (jail_default_allow & arg2) != 0;
                mtx_unlock(&prison0.pr_mtx);
        } else
                i = prison_allow(req->td->td_ucred, arg2);

        if (arg1 != NULL)
                i = !i;
        error = sysctl_handle_int(oidp, &i, 0, req);
        if (error || !req->newptr)
                return (error);
        i = i ? arg2 : 0;
        if (arg1 != NULL)
                i ^= arg2;
        /*
         * The sysctls don't have CTLFLAGS_PRISON, so assume prison0
         * for writing.
         */
        mtx_lock(&prison0.pr_mtx);
        jail_default_allow = (jail_default_allow & ~arg2) | i;
        mtx_unlock(&prison0.pr_mtx);
        return (0);
}

/*
 * Do not add more here. Use SYSCTL_JAIL_PARAM (allow flags for jails)
 * instead.
 */
SYSCTL_PROC(_security_jail, OID_AUTO, set_hostname_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_SET_HOSTNAME, sysctl_jail_default_allow, "I",
    "Processes in jail can set their hostnames (deprecated)");
SYSCTL_PROC(_security_jail, OID_AUTO, socket_unixiproute_only,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    (void *)1, PR_ALLOW_SOCKET_AF, sysctl_jail_default_allow, "I",
    "Processes in jail are limited to creating UNIX/IP/route sockets only (deprecated)");
SYSCTL_PROC(_security_jail, OID_AUTO, sysvipc_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_SYSVIPC, sysctl_jail_default_allow, "I",
    "Processes in jail can use System V IPC primitives (deprecated)");
SYSCTL_PROC(_security_jail, OID_AUTO, allow_raw_sockets,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_RAW_SOCKETS, sysctl_jail_default_allow, "I",
    "Prison root can create raw sockets (deprecated)");
SYSCTL_PROC(_security_jail, OID_AUTO, chflags_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_CHFLAGS, sysctl_jail_default_allow, "I",
    "Processes in jail can alter system file flags (deprecated)");
SYSCTL_PROC(_security_jail, OID_AUTO, mount_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_MOUNT, sysctl_jail_default_allow, "I",
    "Processes in jail can mount/unmount jail-friendly file systems (deprecated)");
SYSCTL_PROC(_security_jail, OID_AUTO, mlock_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_MLOCK, sysctl_jail_default_allow, "I",
    "Processes in jail can lock/unlock physical pages in memory (deprecated)");

static int
sysctl_jail_default_level(SYSCTL_HANDLER_ARGS)
{
        struct prison *pr;
        int level, error;

        pr = req->td->td_ucred->cr_prison;
        level = (pr == &prison0) ? *(int *)arg1 : *(int *)((char *)pr + arg2);
        error = sysctl_handle_int(oidp, &level, 0, req);
        if (error || !req->newptr)
                return (error);
        *(int *)arg1 = level;
        return (0);
}

SYSCTL_PROC(_security_jail, OID_AUTO, enforce_statfs,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    &jail_default_enforce_statfs, offsetof(struct prison, pr_enforce_statfs),
    sysctl_jail_default_level, "I",
    "Processes in jail cannot see all mounted file systems (deprecated)");

SYSCTL_PROC(_security_jail, OID_AUTO, devfs_ruleset,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
    &jail_default_devfs_rsnum, offsetof(struct prison, pr_devfs_rsnum),
    sysctl_jail_default_level, "I",
    "Ruleset for the devfs filesystem in jail (deprecated)");

SYSCTL_NODE(_security_jail, OID_AUTO, children, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Limits and stats of child jails");

static int
sysctl_jail_children(SYSCTL_HANDLER_ARGS)
{
        struct prison *pr;
        int i;

        pr = req->td->td_ucred->cr_prison;

        switch (oidp->oid_kind & CTLTYPE) {
        case CTLTYPE_INT:
                i = *(int *)((char *)pr + arg2);
                return (SYSCTL_OUT(req, &i, sizeof(i)));
        }

        return (0);
}

SYSCTL_PROC(_security_jail_children, OID_AUTO, max,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
    NULL, offsetof(struct prison, pr_childmax), sysctl_jail_children,
    "I", "Maximum number of child jails");
SYSCTL_PROC(_security_jail_children, OID_AUTO, cur,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
    NULL, offsetof(struct prison, pr_childcount), sysctl_jail_children,
    "I", "Current number of child jails");

/*
 * Nodes to describe jail parameters.  Maximum length of string parameters
 * is returned in the string itself, and the other parameters exist merely
 * to make themselves and their types known.
 */
SYSCTL_NODE(_security_jail, OID_AUTO, param, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Jail parameters");

int
sysctl_jail_param(SYSCTL_HANDLER_ARGS)
{
        int i;
        long l;
        size_t s;
        char numbuf[12];

        switch (oidp->oid_kind & CTLTYPE)
        {
        case CTLTYPE_LONG:
        case CTLTYPE_ULONG:
                l = 0;
#ifdef SCTL_MASK32
                if (!(req->flags & SCTL_MASK32))
#endif
                        return (SYSCTL_OUT(req, &l, sizeof(l)));
        case CTLTYPE_INT:
        case CTLTYPE_UINT:
                i = 0;
                return (SYSCTL_OUT(req, &i, sizeof(i)));
        case CTLTYPE_STRING:
                snprintf(numbuf, sizeof(numbuf), "%jd", (intmax_t)arg2);
                return
                    (sysctl_handle_string(oidp, numbuf, sizeof(numbuf), req));
        case CTLTYPE_STRUCT:
                s = (size_t)arg2;
                return (SYSCTL_OUT(req, &s, sizeof(s)));
        }
        return (0);
}

/*
 * CTLFLAG_RDTUN in the following indicates jail parameters that can be set at
 * jail creation time but cannot be changed in an existing jail.
 */
SYSCTL_JAIL_PARAM(, jid, CTLTYPE_INT | CTLFLAG_RDTUN, "I", "Jail ID");
SYSCTL_JAIL_PARAM(, parent, CTLTYPE_INT | CTLFLAG_RD, "I", "Jail parent ID");
SYSCTL_JAIL_PARAM_STRING(, name, CTLFLAG_RW, MAXHOSTNAMELEN, "Jail name");
SYSCTL_JAIL_PARAM_STRING(, path, CTLFLAG_RDTUN, MAXPATHLEN, "Jail root path");
SYSCTL_JAIL_PARAM(, securelevel, CTLTYPE_INT | CTLFLAG_RW,
    "I", "Jail secure level");
SYSCTL_JAIL_PARAM(, osreldate, CTLTYPE_INT | CTLFLAG_RDTUN, "I",
    "Jail value for kern.osreldate and uname -K");
SYSCTL_JAIL_PARAM_STRING(, osrelease, CTLFLAG_RDTUN, OSRELEASELEN,
    "Jail value for kern.osrelease and uname -r");
SYSCTL_JAIL_PARAM(, enforce_statfs, CTLTYPE_INT | CTLFLAG_RW,
    "I", "Jail cannot see all mounted file systems");
SYSCTL_JAIL_PARAM(, devfs_ruleset, CTLTYPE_INT | CTLFLAG_RW,
    "I", "Ruleset for in-jail devfs mounts");
SYSCTL_JAIL_PARAM(, persist, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail persistence");
#ifdef VIMAGE
SYSCTL_JAIL_PARAM(, vnet, CTLTYPE_INT | CTLFLAG_RDTUN,
    "E,jailsys", "Virtual network stack");
#endif
SYSCTL_JAIL_PARAM(, dying, CTLTYPE_INT | CTLFLAG_RD,
    "B", "Jail is in the process of shutting down");

SYSCTL_JAIL_PARAM_NODE(children, "Number of child jails");
SYSCTL_JAIL_PARAM(_children, cur, CTLTYPE_INT | CTLFLAG_RD,
    "I", "Current number of child jails");
SYSCTL_JAIL_PARAM(_children, max, CTLTYPE_INT | CTLFLAG_RW,
    "I", "Maximum number of child jails");

SYSCTL_JAIL_PARAM_SYS_NODE(host, CTLFLAG_RW, "Jail host info");
SYSCTL_JAIL_PARAM_STRING(_host, hostname, CTLFLAG_RW, MAXHOSTNAMELEN,
    "Jail hostname");
SYSCTL_JAIL_PARAM_STRING(_host, domainname, CTLFLAG_RW, MAXHOSTNAMELEN,
    "Jail NIS domainname");
SYSCTL_JAIL_PARAM_STRING(_host, hostuuid, CTLFLAG_RW, HOSTUUIDLEN,
    "Jail host UUID");
SYSCTL_JAIL_PARAM(_host, hostid, CTLTYPE_ULONG | CTLFLAG_RW,
    "LU", "Jail host ID");

SYSCTL_JAIL_PARAM_NODE(cpuset, "Jail cpuset");
SYSCTL_JAIL_PARAM(_cpuset, id, CTLTYPE_INT | CTLFLAG_RD, "I", "Jail cpuset ID");

#ifdef MAC
SYSCTL_JAIL_PARAM_STRUCT(_mac, label, CTLFLAG_RW, sizeof(struct mac),
    "S,mac", "Jail MAC label");
#endif

#ifdef INET
SYSCTL_JAIL_PARAM_SYS_NODE(ip4, CTLFLAG_RDTUN,
    "Jail IPv4 address virtualization");
SYSCTL_JAIL_PARAM_STRUCT(_ip4, addr, CTLFLAG_RW, sizeof(struct in_addr),
    "S,in_addr,a", "Jail IPv4 addresses");
SYSCTL_JAIL_PARAM(_ip4, saddrsel, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Do (not) use IPv4 source address selection rather than the "
    "primary jail IPv4 address.");
#endif
#ifdef INET6
SYSCTL_JAIL_PARAM_SYS_NODE(ip6, CTLFLAG_RDTUN,
    "Jail IPv6 address virtualization");
SYSCTL_JAIL_PARAM_STRUCT(_ip6, addr, CTLFLAG_RW, sizeof(struct in6_addr),
    "S,in6_addr,a", "Jail IPv6 addresses");
SYSCTL_JAIL_PARAM(_ip6, saddrsel, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Do (not) use IPv6 source address selection rather than the "
    "primary jail IPv6 address.");
#endif

SYSCTL_JAIL_PARAM_NODE(allow, "Jail permission flags");
SYSCTL_JAIL_PARAM(_allow, set_hostname, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may set hostname");
SYSCTL_JAIL_PARAM(_allow, sysvipc, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may use SYSV IPC");
SYSCTL_JAIL_PARAM(_allow, raw_sockets, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may create raw sockets");
SYSCTL_JAIL_PARAM(_allow, chflags, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may alter system file flags");
SYSCTL_JAIL_PARAM(_allow, quotas, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may set file quotas");
SYSCTL_JAIL_PARAM(_allow, socket_af, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may create sockets other than just UNIX/IPv4/IPv6/route");
SYSCTL_JAIL_PARAM(_allow, mlock, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may lock (unlock) physical pages in memory");
SYSCTL_JAIL_PARAM(_allow, reserved_ports, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may bind sockets to reserved ports");
SYSCTL_JAIL_PARAM(_allow, read_msgbuf, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may read the kernel message buffer");
SYSCTL_JAIL_PARAM(_allow, unprivileged_proc_debug, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Unprivileged processes may use process debugging facilities");
SYSCTL_JAIL_PARAM(_allow, unprivileged_parent_tampering,
    CTLTYPE_INT | CTLFLAG_RW, "B",
    "Unprivileged parent jail processes may tamper with same-uid processes"
    " (signal/debug/cpuset)");
SYSCTL_JAIL_PARAM(_allow, suser, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Processes in jail with uid 0 have privilege");
#ifdef VIMAGE
SYSCTL_JAIL_PARAM(_allow, nfsd, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Mountd/nfsd may run in the jail");
#endif
SYSCTL_JAIL_PARAM(_allow, extattr, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may set system-level filesystem extended attributes");
SYSCTL_JAIL_PARAM(_allow, adjtime, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may adjust system time");
SYSCTL_JAIL_PARAM(_allow, settime, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may set system time");
SYSCTL_JAIL_PARAM(_allow, routing, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may modify routing table");
#ifdef AUDIT
SYSCTL_JAIL_PARAM(_allow, setaudit, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may set and get audit session state");
#endif

SYSCTL_JAIL_PARAM_SUBNODE(allow, mount, "Jail mount/unmount permission flags");
SYSCTL_JAIL_PARAM(_allow_mount, , CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may mount/unmount jail-friendly file systems in general");

/*
 * Add a dynamic parameter allow.<name>, or allow.<prefix>.<name>.  Return
 * its associated bit in the pr_allow bitmask, or zero if the parameter was
 * not created.
 */
unsigned
prison_add_allow(const char *prefix, const char *name, const char *prefix_descr,
    const char *descr)
{
        struct bool_flags *bf;
        struct sysctl_oid *parent;
        char *allow_name, *allow_noname, *allowed;
#ifndef NO_SYSCTL_DESCR
        char *descr_deprecated;
#endif
        u_int allow_flag;

        if (prefix
            ? asprintf(&allow_name, M_PRISON, "allow.%s.%s", prefix, name)
                < 0 ||
              asprintf(&allow_noname, M_PRISON, "allow.%s.no%s", prefix, name)
                < 0
            : asprintf(&allow_name, M_PRISON, "allow.%s", name) < 0 ||
              asprintf(&allow_noname, M_PRISON, "allow.no%s", name) < 0) {
                free(allow_name, M_PRISON);
                return 0;
        }

        /*
         * See if this parameter has already beed added, i.e. a module was
         * previously loaded/unloaded.
         */
        mtx_lock(&prison0.pr_mtx);
        for (bf = pr_flag_allow;
             bf < pr_flag_allow + nitems(pr_flag_allow) &&
                atomic_load_int(&bf->flag) != 0;
             bf++) {
                if (strcmp(bf->name, allow_name) == 0) {
                        allow_flag = bf->flag;
                        goto no_add;
                }
        }

        /*
         * Find a free bit in pr_allow_all, failing if there are none
         * (which shouldn't happen as long as we keep track of how many
         * potential dynamic flags exist).
         */
        for (allow_flag = 1;; allow_flag <<= 1) {
                if (allow_flag == 0)
                        goto no_add;
                if ((pr_allow_all & allow_flag) == 0)
                        break;
        }

        /* Note the parameter in the next open slot in pr_flag_allow. */
        for (bf = pr_flag_allow; ; bf++) {
                if (bf == pr_flag_allow + nitems(pr_flag_allow)) {
                        /* This should never happen, but is not fatal. */
                        allow_flag = 0;
                        goto no_add;
                }
                if (atomic_load_int(&bf->flag) == 0)
                        break;
        }
        bf->name = allow_name;
        bf->noname = allow_noname;
        pr_allow_all |= allow_flag;
        /*
         * prison0 always has permission for the new parameter.
         * Other jails must have it granted to them.
         */
        prison0.pr_allow |= allow_flag;
        /* The flag indicates a valid entry, so make sure it is set last. */
        atomic_store_rel_int(&bf->flag, allow_flag);
        mtx_unlock(&prison0.pr_mtx);

        /*
         * Create sysctls for the parameter, and the back-compat global
         * permission.
         */
        parent = prefix
            ? SYSCTL_ADD_NODE(NULL,
                  SYSCTL_CHILDREN(&sysctl___security_jail_param_allow),
                  OID_AUTO, prefix, CTLFLAG_MPSAFE, 0, prefix_descr)
            : &sysctl___security_jail_param_allow;
        (void)SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(parent), OID_AUTO,
            name, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
            NULL, 0, sysctl_jail_param, "B", descr);
        if ((prefix
             ? asprintf(&allowed, M_TEMP, "%s_%s_allowed", prefix, name)
             : asprintf(&allowed, M_TEMP, "%s_allowed", name)) >= 0) {
#ifndef NO_SYSCTL_DESCR
                (void)asprintf(&descr_deprecated, M_TEMP, "%s (deprecated)",
                    descr);
#endif
                (void)SYSCTL_ADD_PROC(NULL,
                    SYSCTL_CHILDREN(&sysctl___security_jail), OID_AUTO, allowed,
                    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, allow_flag,
                    sysctl_jail_default_allow, "I", descr_deprecated);
#ifndef NO_SYSCTL_DESCR
                free(descr_deprecated, M_TEMP);
#endif
                free(allowed, M_TEMP);
        }
        return allow_flag;

 no_add:
        mtx_unlock(&prison0.pr_mtx);
        free(allow_name, M_PRISON);
        free(allow_noname, M_PRISON);
        return allow_flag;
}

/*
 * The VFS system will register jail-aware filesystems here.  They each get
 * a parameter allow.mount.xxxfs and a flag to check when a jailed user
 * attempts to mount.
 */
void
prison_add_vfs(struct vfsconf *vfsp)
{
#ifdef NO_SYSCTL_DESCR

        vfsp->vfc_prison_flag = prison_add_allow("mount", vfsp->vfc_name,
            NULL, NULL);
#else
        char *descr;

        (void)asprintf(&descr, M_TEMP, "Jail may mount the %s file system",
            vfsp->vfc_name);
        vfsp->vfc_prison_flag = prison_add_allow("mount", vfsp->vfc_name,
            NULL, descr);
        free(descr, M_TEMP);
#endif
}

#ifdef RACCT
void
prison_racct_foreach(void (*callback)(struct racct *racct,
    void *arg2, void *arg3), void (*pre)(void), void (*post)(void),
    void *arg2, void *arg3)
{
        struct prison_racct *prr;

        ASSERT_RACCT_ENABLED();

        sx_slock(&allprison_lock);
        if (pre != NULL)
                (pre)();
        LIST_FOREACH(prr, &allprison_racct, prr_next)
                (callback)(prr->prr_racct, arg2, arg3);
        if (post != NULL)
                (post)();
        sx_sunlock(&allprison_lock);
}

static struct prison_racct *
prison_racct_find_locked(const char *name)
{
        struct prison_racct *prr;

        ASSERT_RACCT_ENABLED();
        sx_assert(&allprison_lock, SA_XLOCKED);

        if (name[0] == '\0' || strlen(name) >= MAXHOSTNAMELEN)
                return (NULL);

        LIST_FOREACH(prr, &allprison_racct, prr_next) {
                if (strcmp(name, prr->prr_name) != 0)
                        continue;

                /* Found prison_racct with a matching name? */
                prison_racct_hold(prr);
                return (prr);
        }

        /* Add new prison_racct. */
        prr = malloc(sizeof(*prr), M_PRISON_RACCT, M_ZERO | M_WAITOK);
        racct_create(&prr->prr_racct);

        strcpy(prr->prr_name, name);
        refcount_init(&prr->prr_refcount, 1);
        LIST_INSERT_HEAD(&allprison_racct, prr, prr_next);

        return (prr);
}

struct prison_racct *
prison_racct_find(const char *name)
{
        struct prison_racct *prr;

        ASSERT_RACCT_ENABLED();

        sx_xlock(&allprison_lock);
        prr = prison_racct_find_locked(name);
        sx_xunlock(&allprison_lock);
        return (prr);
}

void
prison_racct_hold(struct prison_racct *prr)
{

        ASSERT_RACCT_ENABLED();

        refcount_acquire(&prr->prr_refcount);
}

static void
prison_racct_free_locked(struct prison_racct *prr)
{

        ASSERT_RACCT_ENABLED();
        sx_assert(&allprison_lock, SA_XLOCKED);

        if (refcount_release(&prr->prr_refcount)) {
                racct_destroy(&prr->prr_racct);
                LIST_REMOVE(prr, prr_next);
                free(prr, M_PRISON_RACCT);
        }
}

void
prison_racct_free(struct prison_racct *prr)
{

        ASSERT_RACCT_ENABLED();
        sx_assert(&allprison_lock, SA_UNLOCKED);

        if (refcount_release_if_not_last(&prr->prr_refcount))
                return;

        sx_xlock(&allprison_lock);
        prison_racct_free_locked(prr);
        sx_xunlock(&allprison_lock);
}

static void
prison_racct_attach(struct prison *pr)
{
        struct prison_racct *prr;

        ASSERT_RACCT_ENABLED();
        sx_assert(&allprison_lock, SA_XLOCKED);

        prr = prison_racct_find_locked(pr->pr_name);
        KASSERT(prr != NULL, ("cannot find prison_racct"));

        pr->pr_prison_racct = prr;
}

/*
 * Handle jail renaming.  From the racct point of view, renaming means
 * moving from one prison_racct to another.
 */
static void
prison_racct_modify(struct prison *pr)
{
#ifdef RCTL
        struct proc *p;
        struct ucred *cred;
#endif
        struct prison_racct *oldprr;

        ASSERT_RACCT_ENABLED();

        sx_slock(&allproc_lock);
        sx_xlock(&allprison_lock);

        if (strcmp(pr->pr_name, pr->pr_prison_racct->prr_name) == 0) {
                sx_xunlock(&allprison_lock);
                sx_sunlock(&allproc_lock);
                return;
        }

        oldprr = pr->pr_prison_racct;
        pr->pr_prison_racct = NULL;

        prison_racct_attach(pr);

        /*
         * Move resource utilisation records.
         */
        racct_move(pr->pr_prison_racct->prr_racct, oldprr->prr_racct);

#ifdef RCTL
        /*
         * Force rctl to reattach rules to processes.
         */
        FOREACH_PROC_IN_SYSTEM(p) {
                PROC_LOCK(p);
                cred = crhold(p->p_ucred);
                PROC_UNLOCK(p);
                rctl_proc_ucred_changed(p, cred);
                crfree(cred);
        }
#endif

        sx_sunlock(&allproc_lock);
        prison_racct_free_locked(oldprr);
        sx_xunlock(&allprison_lock);
}

static void
prison_racct_detach(struct prison *pr)
{

        ASSERT_RACCT_ENABLED();
        sx_assert(&allprison_lock, SA_UNLOCKED);

        if (pr->pr_prison_racct == NULL)
                return;
        prison_racct_free(pr->pr_prison_racct);
        pr->pr_prison_racct = NULL;
}
#endif /* RACCT */

/*
 * Submit a knote for a prison, locking if necessary.
 */
static void
prison_knote(struct prison *pr, long hint)
{
        int locked;

        locked = mtx_owned(&pr->pr_mtx);
        if (!locked)
                mtx_lock(&pr->pr_mtx);
        KNOTE_LOCKED(pr->pr_klist, hint);
        jaildesc_knote(pr, hint);
        if (!locked)
                mtx_unlock(&pr->pr_mtx);
}

#ifdef DDB

static void
db_show_prison(struct prison *pr)
{
        struct bool_flags *bf;
        struct jailsys_flags *jsf;
#if defined(INET) || defined(INET6)
        int ii;
        struct prison_ip *pip;
#endif
        unsigned f;
#ifdef INET
        char ip4buf[INET_ADDRSTRLEN];
#endif
#ifdef INET6
        char ip6buf[INET6_ADDRSTRLEN];
#endif

        db_printf("prison %p:\n", pr);
        db_printf(" jid             = %d\n", pr->pr_id);
        db_printf(" name            = %s\n", pr->pr_name);
        db_printf(" parent          = %p\n", pr->pr_parent);
        db_printf(" ref             = %d\n", pr->pr_ref);
        db_printf(" uref            = %d\n", pr->pr_uref);
        db_printf(" state           = %s\n",
            pr->pr_state == PRISON_STATE_ALIVE ? "alive" :
            pr->pr_state == PRISON_STATE_DYING ? "dying" :
            "invalid");
        db_printf(" path            = %s\n", pr->pr_path);
        db_printf(" cpuset          = %d\n", pr->pr_cpuset
            ? pr->pr_cpuset->cs_id : -1);
#ifdef VIMAGE
        db_printf(" vnet            = %p\n", pr->pr_vnet);
#endif
        db_printf(" root            = %p\n", pr->pr_root);
        db_printf(" securelevel     = %d\n", pr->pr_securelevel);
        db_printf(" devfs_rsnum     = %d\n", pr->pr_devfs_rsnum);
        db_printf(" children.max    = %d\n", pr->pr_childmax);
        db_printf(" children.cur    = %d\n", pr->pr_childcount);
        db_printf(" child           = %p\n", LIST_FIRST(&pr->pr_children));
        db_printf(" sibling         = %p\n", LIST_NEXT(pr, pr_sibling));
        db_printf(" flags           = 0x%x", pr->pr_flags);
        for (bf = pr_flag_bool; bf < pr_flag_bool + nitems(pr_flag_bool); bf++)
                if (pr->pr_flags & bf->flag)
                        db_printf(" %s", bf->name);
        for (jsf = pr_flag_jailsys;
             jsf < pr_flag_jailsys + nitems(pr_flag_jailsys);
             jsf++) {
                f = pr->pr_flags & (jsf->disable | jsf->new);
                db_printf(" %-16s= %s\n", jsf->name,
                    (f != 0 && f == jsf->disable) ? "disable"
                    : (f == jsf->new) ? "new"
                    : "inherit");
        }
        db_printf(" allow           = 0x%x", pr->pr_allow);
        for (bf = pr_flag_allow;
             bf < pr_flag_allow + nitems(pr_flag_allow) &&
                atomic_load_int(&bf->flag) != 0;
             bf++)
                if (pr->pr_allow & bf->flag)
                        db_printf(" %s", bf->name);
        db_printf("\n");
        db_printf(" enforce_statfs  = %d\n", pr->pr_enforce_statfs);
        db_printf(" host.hostname   = %s\n", pr->pr_hostname);
        db_printf(" host.domainname = %s\n", pr->pr_domainname);
        db_printf(" host.hostuuid   = %s\n", pr->pr_hostuuid);
        db_printf(" host.hostid     = %lu\n", pr->pr_hostid);
#ifdef INET
        if ((pip = pr->pr_addrs[PR_INET]) != NULL) {
                db_printf(" ip4s            = %d\n", pip->ips);
                for (ii = 0; ii < pip->ips; ii++)
                        db_printf(" %s %s\n",
                            ii == 0 ? "ip4.addr        =" : "                 ",
                            inet_ntoa_r(
                            *(const struct in_addr *)PR_IP(pip, PR_INET, ii),
                            ip4buf));
        }
#endif
#ifdef INET6
        if ((pip = pr->pr_addrs[PR_INET6]) != NULL) {
                db_printf(" ip6s            = %d\n", pip->ips);
                for (ii = 0; ii < pip->ips; ii++)
                        db_printf(" %s %s\n",
                            ii == 0 ? "ip6.addr        =" : "                 ",
                            ip6_sprintf(ip6buf,
                            (const struct in6_addr *)PR_IP(pip, PR_INET6, ii)));
        }
#endif
}

DB_SHOW_COMMAND(prison, db_show_prison_command)
{
        struct prison *pr;

        if (!have_addr) {
                /*
                 * Show all prisons in the list, and prison0 which is not
                 * listed.
                 */
                db_show_prison(&prison0);
                if (!db_pager_quit) {
                        TAILQ_FOREACH(pr, &allprison, pr_list) {
                                db_show_prison(pr);
                                if (db_pager_quit)
                                        break;
                        }
                }
                return;
        }

        if (addr == 0)
                pr = &prison0;
        else {
                /* Look for a prison with the ID and with references. */
                TAILQ_FOREACH(pr, &allprison, pr_list)
                        if (pr->pr_id == addr && pr->pr_ref > 0)
                                break;
                if (pr == NULL)
                        /* Look again, without requiring a reference. */
                        TAILQ_FOREACH(pr, &allprison, pr_list)
                                if (pr->pr_id == addr)
                                        break;
                if (pr == NULL)
                        /* Assume address points to a valid prison. */
                        pr = (struct prison *)addr;
        }
        db_show_prison(pr);
}

#endif /* DDB */