/*-
 * Implementation of SVID messages
 *
 * Author:  Daniel Boulet
 *
 * Copyright 1993 Daniel Boulet and RTMX Inc.
 *
 * This system call was implemented by Daniel Boulet under contract from RTMX.
 *
 * Redistribution and use in source forms, with and without modification,
 * are permitted provided that this entire comment appears intact.
 *
 * Redistribution in binary form may occur without any restrictions.
 * Obviously, it would be nice if you gave credit where credit is due
 * but requiring it would be too onerous.
 *
 * This software is provided ``AS IS'' without any warranties of any kind.
 */
/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2003-2005 McAfee, Inc.
 * Copyright (c) 2016-2017 Robert N. M. Watson
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project in part by McAfee
 * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
 * program.
 *
 * Portions of this software were developed by BAE Systems, the University of
 * Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL
 * contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent
 * Computing (TC) research program.
 *
 * 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 "opt_sysvipc.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/msg.h>
#include <sys/racct.h>
#include <sys/sx.h>
#include <sys/syscall.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/jail.h>

#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>

FEATURE(sysv_msg, "System V message queues support");

static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues");

static int msginit(void);
static int msgunload(void);
static int sysvmsg_modload(struct module *, int, void *);
static void msq_remove(struct msqid_kernel *);
static struct prison *msg_find_prison(struct ucred *);
static int msq_prison_cansee(struct prison *, struct msqid_kernel *);
static int msg_prison_check(void *, void *);
static int msg_prison_set(void *, void *);
static int msg_prison_get(void *, void *);
static int msg_prison_remove(void *, void *);
static void msg_prison_cleanup(struct prison *);

#ifdef MSG_DEBUG
#define DPRINTF(a)      printf a
#else
#define DPRINTF(a)      (void)0
#endif

static void msg_freehdr(struct msg *msghdr);

#ifndef MSGSSZ
#define MSGSSZ  8               /* Each segment must be 2^N long */
#endif
#ifndef MSGSEG
#define MSGSEG  2048            /* must be less than 32767 */
#endif
#define MSGMAX  (MSGSSZ*MSGSEG)
#ifndef MSGMNB
#define MSGMNB  2048            /* max # of bytes in a queue */
#endif
#ifndef MSGMNI
#define MSGMNI  40
#endif
#ifndef MSGTQL
#define MSGTQL  40
#endif

/*
 * Based on the configuration parameters described in an SVR2 (yes, two)
 * config(1m) man page.
 *
 * Each message is broken up and stored in segments that are msgssz bytes
 * long.  For efficiency reasons, this should be a power of two.  Also,
 * it doesn't make sense if it is less than 8 or greater than about 256.
 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
 * two between 8 and 1024 inclusive (and panic's if it isn't).
 */
struct msginfo msginfo = {
                MSGMAX,         /* max chars in a message */
                MSGMNI,         /* # of message queue identifiers */
                MSGMNB,         /* max chars in a queue */
                MSGTQL,         /* max messages in system */
                MSGSSZ,         /* size of a message segment */
                                /* (must be small power of 2 greater than 4) */
                MSGSEG          /* number of message segments */
};

/*
 * macros to convert between msqid_ds's and msqid's.
 * (specific to this implementation)
 */
#define MSQID(ix,ds)    ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
#define MSQID_IX(id)    ((id) & 0xffff)
#define MSQID_SEQ(id)   (((id) >> 16) & 0xffff)

/*
 * The rest of this file is specific to this particular implementation.
 */

struct msgmap {
        short   next;           /* next segment in buffer */
                                /* -1 -> available */
                                /* 0..(MSGSEG-1) -> index of next segment */
};

#define MSG_LOCKED      01000   /* Is this msqid_ds locked? */

static int nfree_msgmaps;       /* # of free map entries */
static short free_msgmaps;      /* head of linked list of free map entries */
static struct msg *free_msghdrs;/* list of free msg headers */
static char *msgpool;           /* MSGMAX byte long msg buffer pool */
static struct msgmap *msgmaps;  /* MSGSEG msgmap structures */
static struct msg *msghdrs;     /* MSGTQL msg headers */
static struct msqid_kernel *msqids;     /* MSGMNI msqid_kernel struct's */
static struct mtx msq_mtx;      /* global mutex for message queues. */
static unsigned msg_prison_slot;/* prison OSD slot */

static struct syscall_helper_data msg_syscalls[] = {
        SYSCALL_INIT_HELPER(msgctl),
        SYSCALL_INIT_HELPER(msgget),
        SYSCALL_INIT_HELPER(msgsnd),
        SYSCALL_INIT_HELPER(msgrcv),
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
    defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
        SYSCALL_INIT_HELPER(msgsys),
        SYSCALL_INIT_HELPER_COMPAT(freebsd7_msgctl),
#endif
        SYSCALL_INIT_LAST
};

#ifdef COMPAT_FREEBSD32
#include <compat/freebsd32/freebsd32.h>
#include <compat/freebsd32/freebsd32_ipc.h>
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_signal.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_util.h>

static struct syscall_helper_data msg32_syscalls[] = {
        SYSCALL32_INIT_HELPER(freebsd32_msgctl),
        SYSCALL32_INIT_HELPER(freebsd32_msgsnd),
        SYSCALL32_INIT_HELPER(freebsd32_msgrcv),
        SYSCALL32_INIT_HELPER_COMPAT(msgget),
        SYSCALL32_INIT_HELPER(freebsd32_msgsys),
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
    defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
        SYSCALL32_INIT_HELPER(freebsd7_freebsd32_msgctl),
#endif
        SYSCALL_INIT_LAST
};
#endif

static int
msginit(void)
{
        struct prison *pr;
        void **rsv;
        int i, error;
        osd_method_t methods[PR_MAXMETHOD] = {
            [PR_METHOD_CHECK] =         msg_prison_check,
            [PR_METHOD_SET] =           msg_prison_set,
            [PR_METHOD_GET] =           msg_prison_get,
            [PR_METHOD_REMOVE] =        msg_prison_remove,
        };

        msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
        msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK);
        msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK);
        msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK);
        msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG,
            M_WAITOK | M_ZERO);

        /*
         * msginfo.msgssz should be a power of two for efficiency reasons.
         * It is also pretty silly if msginfo.msgssz is less than 8
         * or greater than about 256 so ...
         */

        i = 8;
        while (i < 1024 && i != msginfo.msgssz)
                i <<= 1;
        if (i != msginfo.msgssz) {
                DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
                    msginfo.msgssz));
                panic("msginfo.msgssz not a small power of 2");
        }

        if (msginfo.msgseg > 32767) {
                DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
                panic("msginfo.msgseg > 32767");
        }

        for (i = 0; i < msginfo.msgseg; i++) {
                if (i > 0)
                        msgmaps[i-1].next = i;
                msgmaps[i].next = -1;   /* implies entry is available */
        }
        free_msgmaps = 0;
        nfree_msgmaps = msginfo.msgseg;

        for (i = 0; i < msginfo.msgtql; i++) {
                msghdrs[i].msg_type = 0;
                if (i > 0)
                        msghdrs[i-1].msg_next = &msghdrs[i];
                msghdrs[i].msg_next = NULL;
#ifdef MAC
                mac_sysvmsg_init(&msghdrs[i]);
#endif
        }
        free_msghdrs = &msghdrs[0];

        for (i = 0; i < msginfo.msgmni; i++) {
                msqids[i].u.msg_qbytes = 0;     /* implies entry is available */
                msqids[i].u.msg_perm.seq = 0;   /* reset to a known value */
                msqids[i].u.msg_perm.mode = 0;
#ifdef MAC
                mac_sysvmsq_init(&msqids[i]);
#endif
        }
        mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);

        /* Set current prisons according to their allow.sysvipc. */
        msg_prison_slot = osd_jail_register(NULL, methods);
        rsv = osd_reserve(msg_prison_slot);
        prison_lock(&prison0);
        (void)osd_jail_set_reserved(&prison0, msg_prison_slot, rsv, &prison0);
        prison_unlock(&prison0);
        rsv = NULL;
        sx_slock(&allprison_lock);
        TAILQ_FOREACH(pr, &allprison, pr_list) {
                if (rsv == NULL)
                        rsv = osd_reserve(msg_prison_slot);
                prison_lock(pr);
                if (pr->pr_allow & PR_ALLOW_SYSVIPC) {
                        (void)osd_jail_set_reserved(pr, msg_prison_slot, rsv,
                            &prison0);
                        rsv = NULL;
                }
                prison_unlock(pr);
        }
        if (rsv != NULL)
                osd_free_reserved(rsv);
        sx_sunlock(&allprison_lock);

        error = syscall_helper_register(msg_syscalls, SY_THR_STATIC_KLD);
        if (error != 0)
                return (error);
#ifdef COMPAT_FREEBSD32
        error = syscall32_helper_register(msg32_syscalls, SY_THR_STATIC_KLD);
        if (error != 0)
                return (error);
#endif
        return (0);
}

static int
msgunload(void)
{
        struct msqid_kernel *msqkptr;
        int msqid;
#ifdef MAC
        int i;
#endif

        syscall_helper_unregister(msg_syscalls);
#ifdef COMPAT_FREEBSD32
        syscall32_helper_unregister(msg32_syscalls);
#endif

        for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
                msqkptr = &msqids[msqid];
                if (msqkptr->u.msg_qbytes != 0 ||
                    (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
                        break;
        }
        if (msqid != msginfo.msgmni)
                return (EBUSY);

        if (msg_prison_slot != 0)
                osd_jail_deregister(msg_prison_slot);
#ifdef MAC
        for (i = 0; i < msginfo.msgtql; i++)
                mac_sysvmsg_destroy(&msghdrs[i]);
        for (msqid = 0; msqid < msginfo.msgmni; msqid++)
                mac_sysvmsq_destroy(&msqids[msqid]);
#endif
        free(msgpool, M_MSG);
        free(msgmaps, M_MSG);
        free(msghdrs, M_MSG);
        free(msqids, M_MSG);
        mtx_destroy(&msq_mtx);
        return (0);
}

static int
sysvmsg_modload(struct module *module, int cmd, void *arg)
{
        int error = 0;

        switch (cmd) {
        case MOD_LOAD:
                error = msginit();
                if (error != 0)
                        msgunload();
                break;
        case MOD_UNLOAD:
                error = msgunload();
                break;
        case MOD_SHUTDOWN:
                break;
        default:
                error = EINVAL;
                break;
        }
        return (error);
}

static moduledata_t sysvmsg_mod = {
        "sysvmsg",
        &sysvmsg_modload,
        NULL
};

DECLARE_MODULE(sysvmsg, sysvmsg_mod, SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
MODULE_VERSION(sysvmsg, 1);

static void
msg_freehdr(struct msg *msghdr)
{
        while (msghdr->msg_ts > 0) {
                short next;
                if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
                        panic("msghdr->msg_spot out of range");
                next = msgmaps[msghdr->msg_spot].next;
                msgmaps[msghdr->msg_spot].next = free_msgmaps;
                free_msgmaps = msghdr->msg_spot;
                nfree_msgmaps++;
                msghdr->msg_spot = next;
                if (msghdr->msg_ts >= msginfo.msgssz)
                        msghdr->msg_ts -= msginfo.msgssz;
                else
                        msghdr->msg_ts = 0;
        }
        if (msghdr->msg_spot != -1)
                panic("msghdr->msg_spot != -1");
        msghdr->msg_next = free_msghdrs;
        free_msghdrs = msghdr;
#ifdef MAC
        mac_sysvmsg_cleanup(msghdr);
#endif
}

static void
msq_remove(struct msqid_kernel *msqkptr)
{
        struct msg *msghdr;

        racct_sub_cred(msqkptr->cred, RACCT_NMSGQ, 1);
        racct_sub_cred(msqkptr->cred, RACCT_MSGQQUEUED, msqkptr->u.msg_qnum);
        racct_sub_cred(msqkptr->cred, RACCT_MSGQSIZE, msqkptr->u.msg_cbytes);
        crfree(msqkptr->cred);
        msqkptr->cred = NULL;

        /* Free the message headers */
        msghdr = msqkptr->u.__msg_first;
        while (msghdr != NULL) {
                struct msg *msghdr_tmp;

                /* Free the segments of each message */
                msqkptr->u.msg_cbytes -= msghdr->msg_ts;
                msqkptr->u.msg_qnum--;
                msghdr_tmp = msghdr;
                msghdr = msghdr->msg_next;
                msg_freehdr(msghdr_tmp);
        }

        if (msqkptr->u.msg_cbytes != 0)
                panic("msg_cbytes is screwed up");
        if (msqkptr->u.msg_qnum != 0)
                panic("msg_qnum is screwed up");

        msqkptr->u.msg_qbytes = 0;      /* Mark it as free */

#ifdef MAC
        mac_sysvmsq_cleanup(msqkptr);
#endif

        wakeup(msqkptr);
}

static struct prison *
msg_find_prison(struct ucred *cred)
{
        struct prison *pr, *rpr;

        pr = cred->cr_prison;
        prison_lock(pr);
        rpr = osd_jail_get(pr, msg_prison_slot);
        prison_unlock(pr);
        return rpr;
}

static int
msq_prison_cansee(struct prison *rpr, struct msqid_kernel *msqkptr)
{

        if (msqkptr->cred == NULL ||
            !(rpr == msqkptr->cred->cr_prison ||
              prison_ischild(rpr, msqkptr->cred->cr_prison)))
                return (EINVAL);
        return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct msgctl_args {
        int     msqid;
        int     cmd;
        struct  msqid_ds *buf;
};
#endif
int
sys_msgctl(struct thread *td, struct msgctl_args *uap)
{
        int msqid = uap->msqid;
        int cmd = uap->cmd;
        struct msqid_ds msqbuf;
        int error;

        DPRINTF(("call to msgctl(%d, %d, %p)\n", msqid, cmd, uap->buf));
        if (cmd == IPC_SET &&
            (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0)
                return (error);
        error = kern_msgctl(td, msqid, cmd, &msqbuf);
        if (cmd == IPC_STAT && error == 0)
                error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds));
        return (error);
}

int
kern_msgctl(struct thread *td, int msqid, int cmd, struct msqid_ds *msqbuf)
{
        int rval, error, msqix;
        struct msqid_kernel *msqkptr;
        struct prison *rpr;

        rpr = msg_find_prison(td->td_ucred);
        if (rpr == NULL)
                return (ENOSYS);

        AUDIT_ARG_SVIPC_CMD(cmd);
        AUDIT_ARG_SVIPC_ID(msqid);
        msqix = IPCID_TO_IX(msqid);

        if (msqix < 0 || msqix >= msginfo.msgmni) {
                DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
                    msginfo.msgmni));
                return (EINVAL);
        }

        msqkptr = &msqids[msqix];

        mtx_lock(&msq_mtx);
        if (msqkptr->u.msg_qbytes == 0) {
                DPRINTF(("no such msqid\n"));
                error = EINVAL;
                goto done2;
        }
        if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
                DPRINTF(("wrong sequence number\n"));
                error = EINVAL;
                goto done2;
        }

        error = msq_prison_cansee(rpr, msqkptr);
        if (error != 0) {
                DPRINTF(("requester can't see prison\n"));
                goto done2;
        }

#ifdef MAC
        error = mac_sysvmsq_check_msqctl(td->td_ucred, msqkptr, cmd);
        if (error != 0)
                goto done2;
#endif

        error = 0;
        rval = 0;

        switch (cmd) {
        case IPC_RMID:
        {
#ifdef MAC
                struct msg *msghdr;
#endif
                if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
                        goto done2;

#ifdef MAC
                /*
                 * Check that the thread has MAC access permissions to
                 * individual msghdrs.  Note: We need to do this in a
                 * separate loop because the actual loop alters the
                 * msq/msghdr info as it progresses, and there is no going
                 * back if half the way through we discover that the
                 * thread cannot free a certain msghdr.  The msq will get
                 * into an inconsistent state.
                 */
                for (msghdr = msqkptr->u.__msg_first; msghdr != NULL;
                    msghdr = msghdr->msg_next) {
                        error = mac_sysvmsq_check_msgrmid(td->td_ucred, msghdr);
                        if (error != 0)
                                goto done2;
                }
#endif

                msq_remove(msqkptr);
        }

                break;

        case IPC_SET:
                AUDIT_ARG_SVIPC_PERM(&msqbuf->msg_perm);
                if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
                        goto done2;
                if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) {
                        error = priv_check(td, PRIV_IPC_MSGSIZE);
                        if (error)
                                goto done2;
                }
                if (msqbuf->msg_qbytes > msginfo.msgmnb) {
                        DPRINTF(("can't increase msg_qbytes beyond %d"
                            "(truncating)\n", msginfo.msgmnb));
                        msqbuf->msg_qbytes = msginfo.msgmnb;    /* silently restrict qbytes to system limit */
                }
                if (msqbuf->msg_qbytes == 0) {
                        DPRINTF(("can't reduce msg_qbytes to 0\n"));
                        error = EINVAL;         /* non-standard errno! */
                        goto done2;
                }
                msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */
                msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */
                msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) |
                    (msqbuf->msg_perm.mode & 0777);
                msqkptr->u.msg_qbytes = msqbuf->msg_qbytes;
                msqkptr->u.msg_ctime = time_second;
                break;

        case IPC_STAT:
                if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
                        DPRINTF(("requester doesn't have read access\n"));
                        goto done2;
                }
                *msqbuf = msqkptr->u;
                if (td->td_ucred->cr_prison != msqkptr->cred->cr_prison)
                        msqbuf->msg_perm.key = IPC_PRIVATE;

                /*
                 * Try to hide the fact that the structure layout is shared by
                 * both the kernel and userland.  These pointers are not useful
                 * to userspace.
                 */
                msqbuf->__msg_first = msqbuf->__msg_last = NULL;
                break;

        default:
                DPRINTF(("invalid command %d\n", cmd));
                error = EINVAL;
                goto done2;
        }

        if (error == 0)
                td->td_retval[0] = rval;
done2:
        mtx_unlock(&msq_mtx);
        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct msgget_args {
        key_t   key;
        int     msgflg;
};
#endif

int
sys_msgget(struct thread *td, struct msgget_args *uap)
{
        int msqid, error = 0;
        int key = uap->key;
        int msgflg = uap->msgflg;
        struct ucred *cred = td->td_ucred;
        struct msqid_kernel *msqkptr = NULL;

        DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));

        if (msg_find_prison(cred) == NULL)
                return (ENOSYS);

        mtx_lock(&msq_mtx);
        if (key != IPC_PRIVATE) {
                for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
                        msqkptr = &msqids[msqid];
                        if (msqkptr->u.msg_qbytes != 0 &&
                            msqkptr->cred != NULL &&
                            msqkptr->cred->cr_prison == cred->cr_prison &&
                            msqkptr->u.msg_perm.key == key)
                                break;
                }
                if (msqid < msginfo.msgmni) {
                        DPRINTF(("found public key\n"));
                        if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
                                DPRINTF(("not exclusive\n"));
                                error = EEXIST;
                                goto done2;
                        }
                        AUDIT_ARG_SVIPC_ID(IXSEQ_TO_IPCID(msqid,
                            msqkptr->u.msg_perm));
                        if ((error = ipcperm(td, &msqkptr->u.msg_perm,
                            msgflg & 0700))) {
                                DPRINTF(("requester doesn't have 0%o access\n",
                                    msgflg & 0700));
                                goto done2;
                        }
#ifdef MAC
                        error = mac_sysvmsq_check_msqget(cred, msqkptr);
                        if (error != 0)
                                goto done2;
#endif
                        goto found;
                }
        }

        DPRINTF(("need to allocate the msqid_ds\n"));
        if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
                for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
                        /*
                         * Look for an unallocated and unlocked msqid_ds.
                         * msqid_ds's can be locked by msgsnd or msgrcv while
                         * they are copying the message in/out.  We can't
                         * re-use the entry until they release it.
                         */
                        msqkptr = &msqids[msqid];
                        if (msqkptr->u.msg_qbytes == 0 &&
                            (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0)
                                break;
                }
                if (msqid == msginfo.msgmni) {
                        DPRINTF(("no more msqid_ds's available\n"));
                        error = ENOSPC;
                        goto done2;
                }
#ifdef RACCT
                if (racct_enable) {
                        PROC_LOCK(td->td_proc);
                        error = racct_add(td->td_proc, RACCT_NMSGQ, 1);
                        PROC_UNLOCK(td->td_proc);
                        if (error != 0) {
                                error = ENOSPC;
                                goto done2;
                        }
                }
#endif
                DPRINTF(("msqid %d is available\n", msqid));
                msqkptr->u.msg_perm.key = key;
                msqkptr->u.msg_perm.cuid = cred->cr_uid;
                msqkptr->u.msg_perm.uid = cred->cr_uid;
                msqkptr->u.msg_perm.cgid = cred->cr_gid;
                msqkptr->u.msg_perm.gid = cred->cr_gid;
                msqkptr->u.msg_perm.mode = (msgflg & 0777);
                msqkptr->cred = crhold(cred);
                /* Make sure that the returned msqid is unique */
                msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff;
                msqkptr->u.__msg_first = NULL;
                msqkptr->u.__msg_last = NULL;
                msqkptr->u.msg_cbytes = 0;
                msqkptr->u.msg_qnum = 0;
                msqkptr->u.msg_qbytes = msginfo.msgmnb;
                msqkptr->u.msg_lspid = 0;
                msqkptr->u.msg_lrpid = 0;
                msqkptr->u.msg_stime = 0;
                msqkptr->u.msg_rtime = 0;
                msqkptr->u.msg_ctime = time_second;
#ifdef MAC
                mac_sysvmsq_create(cred, msqkptr);
#endif
                AUDIT_ARG_SVIPC_PERM(&msqkptr->u.msg_perm);
        } else {
                DPRINTF(("didn't find it and wasn't asked to create it\n"));
                error = ENOENT;
                goto done2;
        }

found:
        /* Construct the unique msqid */
        td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm);
done2:
        mtx_unlock(&msq_mtx);
        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct msgsnd_args {
        int     msqid;
        const void      *msgp;  /* XXX msgp is actually mtext. */
        size_t  msgsz;
        int     msgflg;
};
#endif
int
kern_msgsnd(struct thread *td, int msqid, const void *msgp,
    size_t msgsz, int msgflg, long mtype)
{
        int msqix, segs_needed, error = 0;
        struct msqid_kernel *msqkptr;
        struct msg *msghdr;
        struct prison *rpr;
        short next;
#ifdef RACCT
        size_t saved_msgsz = 0;
#endif

        rpr = msg_find_prison(td->td_ucred);
        if (rpr == NULL)
                return (ENOSYS);

        mtx_lock(&msq_mtx);
        AUDIT_ARG_SVIPC_ID(msqid);
        msqix = IPCID_TO_IX(msqid);

        if (msqix < 0 || msqix >= msginfo.msgmni) {
                DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
                    msginfo.msgmni));
                error = EINVAL;
                goto done2;
        }

        msqkptr = &msqids[msqix];
        AUDIT_ARG_SVIPC_PERM(&msqkptr->u.msg_perm);
        if (msqkptr->u.msg_qbytes == 0) {
                DPRINTF(("no such message queue id\n"));
                error = EINVAL;
                goto done2;
        }
        if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
                DPRINTF(("wrong sequence number\n"));
                error = EINVAL;
                goto done2;
        }

        if ((error = msq_prison_cansee(rpr, msqkptr))) {
                DPRINTF(("requester can't see prison\n"));
                goto done2;
        }

        if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) {
                DPRINTF(("requester doesn't have write access\n"));
                goto done2;
        }

#ifdef MAC
        error = mac_sysvmsq_check_msqsnd(td->td_ucred, msqkptr);
        if (error != 0)
                goto done2;
#endif

#ifdef RACCT
        if (racct_enable) {
                PROC_LOCK(td->td_proc);
                if (racct_add(td->td_proc, RACCT_MSGQQUEUED, 1)) {
                        PROC_UNLOCK(td->td_proc);
                        error = EAGAIN;
                        goto done2;
                }
                saved_msgsz = msgsz;
                if (racct_add(td->td_proc, RACCT_MSGQSIZE, msgsz)) {
                        racct_sub(td->td_proc, RACCT_MSGQQUEUED, 1);
                        PROC_UNLOCK(td->td_proc);
                        error = EAGAIN;
                        goto done2;
                }
                PROC_UNLOCK(td->td_proc);
        }
#endif

        segs_needed = howmany(msgsz, msginfo.msgssz);
        DPRINTF(("msgsz=%zu, msgssz=%d, segs_needed=%d\n", msgsz,
            msginfo.msgssz, segs_needed));
        for (;;) {
                int need_more_resources = 0;

                /*
                 * check msgsz
                 * (inside this loop in case msg_qbytes changes while we sleep)
                 */

                if (msgsz > msqkptr->u.msg_qbytes) {
                        DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n"));
                        error = EINVAL;
                        goto done3;
                }

                if (msqkptr->u.msg_perm.mode & MSG_LOCKED) {
                        DPRINTF(("msqid is locked\n"));
                        need_more_resources = 1;
                }
                if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) {
                        DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
                        need_more_resources = 1;
                }
                if (segs_needed > nfree_msgmaps) {
                        DPRINTF(("segs_needed > nfree_msgmaps\n"));
                        need_more_resources = 1;
                }
                if (free_msghdrs == NULL) {
                        DPRINTF(("no more msghdrs\n"));
                        need_more_resources = 1;
                }

                if (need_more_resources) {
                        int we_own_it;

                        if ((msgflg & IPC_NOWAIT) != 0) {
                                DPRINTF(("need more resources but caller "
                                    "doesn't want to wait\n"));
                                error = EAGAIN;
                                goto done3;
                        }

                        if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) {
                                DPRINTF(("we don't own the msqid_ds\n"));
                                we_own_it = 0;
                        } else {
                                /* Force later arrivals to wait for our
                                   request */
                                DPRINTF(("we own the msqid_ds\n"));
                                msqkptr->u.msg_perm.mode |= MSG_LOCKED;
                                we_own_it = 1;
                        }
                        DPRINTF(("msgsnd:  goodnight\n"));
                        error = msleep(msqkptr, &msq_mtx, PVFS | PCATCH,
                            "msgsnd", hz);
                        DPRINTF(("msgsnd:  good morning, error=%d\n", error));
                        if (we_own_it)
                                msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
                        if (error == EWOULDBLOCK) {
                                DPRINTF(("msgsnd:  timed out\n"));
                                continue;
                        }
                        if (error != 0) {
                                DPRINTF(("msgsnd:  interrupted system call\n"));
                                error = EINTR;
                                goto done3;
                        }

                        /*
                         * Make sure that the msq queue still exists
                         */

                        if (msqkptr->u.msg_qbytes == 0) {
                                DPRINTF(("msqid deleted\n"));
                                error = EIDRM;
                                goto done3;
                        }

                } else {
                        DPRINTF(("got all the resources that we need\n"));
                        break;
                }
        }

        /*
         * We have the resources that we need.
         * Make sure!
         */

        if (msqkptr->u.msg_perm.mode & MSG_LOCKED)
                panic("msg_perm.mode & MSG_LOCKED");
        if (segs_needed > nfree_msgmaps)
                panic("segs_needed > nfree_msgmaps");
        if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes)
                panic("msgsz + msg_cbytes > msg_qbytes");
        if (free_msghdrs == NULL)
                panic("no more msghdrs");

        /*
         * Re-lock the msqid_ds in case we page-fault when copying in the
         * message
         */

        if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
                panic("msqid_ds is already locked");
        msqkptr->u.msg_perm.mode |= MSG_LOCKED;

        /*
         * Allocate a message header
         */

        msghdr = free_msghdrs;
        free_msghdrs = msghdr->msg_next;
        msghdr->msg_spot = -1;
        msghdr->msg_ts = msgsz;
        msghdr->msg_type = mtype;
#ifdef MAC
        /*
         * XXXMAC: Should the mac_sysvmsq_check_msgmsq check follow here
         * immediately?  Or, should it be checked just before the msg is
         * enqueued in the msgq (as it is done now)?
         */
        mac_sysvmsg_create(td->td_ucred, msqkptr, msghdr);
#endif

        /*
         * Allocate space for the message
         */

        while (segs_needed > 0) {
                if (nfree_msgmaps <= 0)
                        panic("not enough msgmaps");
                if (free_msgmaps == -1)
                        panic("nil free_msgmaps");
                next = free_msgmaps;
                if (next <= -1)
                        panic("next too low #1");
                if (next >= msginfo.msgseg)
                        panic("next out of range #1");
                DPRINTF(("allocating segment %d to message\n", next));
                free_msgmaps = msgmaps[next].next;
                nfree_msgmaps--;
                msgmaps[next].next = msghdr->msg_spot;
                msghdr->msg_spot = next;
                segs_needed--;
        }

        /*
         * Validate the message type
         */

        if (msghdr->msg_type < 1) {
                msg_freehdr(msghdr);
                msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
                wakeup(msqkptr);
                DPRINTF(("mtype (%ld) < 1\n", msghdr->msg_type));
                error = EINVAL;
                goto done3;
        }

        /*
         * Copy in the message body
         */

        next = msghdr->msg_spot;
        while (msgsz > 0) {
                size_t tlen;
                if (msgsz > msginfo.msgssz)
                        tlen = msginfo.msgssz;
                else
                        tlen = msgsz;
                if (next <= -1)
                        panic("next too low #2");
                if (next >= msginfo.msgseg)
                        panic("next out of range #2");
                mtx_unlock(&msq_mtx);
                if ((error = copyin(msgp, &msgpool[next * msginfo.msgssz],
                    tlen)) != 0) {
                        mtx_lock(&msq_mtx);
                        DPRINTF(("error %d copying in message segment\n",
                            error));
                        msg_freehdr(msghdr);
                        msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
                        wakeup(msqkptr);
                        goto done3;
                }
                mtx_lock(&msq_mtx);
                msgsz -= tlen;
                msgp = (const char *)msgp + tlen;
                next = msgmaps[next].next;
        }
        if (next != -1)
                panic("didn't use all the msg segments");

        /*
         * We've got the message.  Unlock the msqid_ds.
         */

        msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;

        /*
         * Make sure that the msqid_ds is still allocated.
         */

        if (msqkptr->u.msg_qbytes == 0) {
                msg_freehdr(msghdr);
                wakeup(msqkptr);
                error = EIDRM;
                goto done3;
        }

#ifdef MAC
        /*
         * Note: Since the task/thread allocates the msghdr and usually
         * primes it with its own MAC label, for a majority of policies, it
         * won't be necessary to check whether the msghdr has access
         * permissions to the msgq.  The mac_sysvmsq_check_msqsnd check would
         * suffice in that case.  However, this hook may be required where
         * individual policies derive a non-identical label for the msghdr
         * from the current thread label and may want to check the msghdr
         * enqueue permissions, along with read/write permissions to the
         * msgq.
         */
        error = mac_sysvmsq_check_msgmsq(td->td_ucred, msghdr, msqkptr);
        if (error != 0) {
                msg_freehdr(msghdr);
                wakeup(msqkptr);
                goto done3;
        }
#endif

        /*
         * Put the message into the queue
         */
        if (msqkptr->u.__msg_first == NULL) {
                msqkptr->u.__msg_first = msghdr;
                msqkptr->u.__msg_last = msghdr;
        } else {
                msqkptr->u.__msg_last->msg_next = msghdr;
                msqkptr->u.__msg_last = msghdr;
        }
        msqkptr->u.__msg_last->msg_next = NULL;

        msqkptr->u.msg_cbytes += msghdr->msg_ts;
        msqkptr->u.msg_qnum++;
        msqkptr->u.msg_lspid = td->td_proc->p_pid;
        msqkptr->u.msg_stime = time_second;

        wakeup(msqkptr);
        td->td_retval[0] = 0;
done3:
#ifdef RACCT
        if (racct_enable && error != 0) {
                PROC_LOCK(td->td_proc);
                racct_sub(td->td_proc, RACCT_MSGQQUEUED, 1);
                racct_sub(td->td_proc, RACCT_MSGQSIZE, saved_msgsz);
                PROC_UNLOCK(td->td_proc);
        }
#endif
done2:
        mtx_unlock(&msq_mtx);
        return (error);
}

int
sys_msgsnd(struct thread *td, struct msgsnd_args *uap)
{
        int error;
        long mtype;

        DPRINTF(("call to msgsnd(%d, %p, %zu, %d)\n", uap->msqid, uap->msgp,
            uap->msgsz, uap->msgflg));

        if ((error = copyin(uap->msgp, &mtype, sizeof(mtype))) != 0) {
                DPRINTF(("error %d copying the message type\n", error));
                return (error);
        }
        return (kern_msgsnd(td, uap->msqid,
            (const char *)uap->msgp + sizeof(mtype),
            uap->msgsz, uap->msgflg, mtype));
}

#ifndef _SYS_SYSPROTO_H_
struct msgrcv_args {
        int     msqid;
        void    *msgp;
        size_t  msgsz;
        long    msgtyp;
        int     msgflg;
};
#endif
/* XXX msgp is actually mtext. */
int
kern_msgrcv(struct thread *td, int msqid, void *msgp, size_t msgsz, long msgtyp,
    int msgflg, long *mtype)
{
        size_t len;
        struct msqid_kernel *msqkptr;
        struct msg *msghdr;
        struct prison *rpr;
        int msqix, error = 0;
        short next;

        rpr = msg_find_prison(td->td_ucred);
        if (rpr == NULL)
                return (ENOSYS);

        AUDIT_ARG_SVIPC_ID(msqid);
        msqix = IPCID_TO_IX(msqid);

        if (msqix < 0 || msqix >= msginfo.msgmni) {
                DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
                    msginfo.msgmni));
                return (EINVAL);
        }

        msqkptr = &msqids[msqix];
        mtx_lock(&msq_mtx);
        AUDIT_ARG_SVIPC_PERM(&msqkptr->u.msg_perm);
        if (msqkptr->u.msg_qbytes == 0) {
                DPRINTF(("no such message queue id\n"));
                error = EINVAL;
                goto done2;
        }
        if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
                DPRINTF(("wrong sequence number\n"));
                error = EINVAL;
                goto done2;
        }

        if ((error = msq_prison_cansee(rpr, msqkptr))) {
                DPRINTF(("requester can't see prison\n"));
                goto done2;
        }

        if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
                DPRINTF(("requester doesn't have read access\n"));
                goto done2;
        }

#ifdef MAC
        error = mac_sysvmsq_check_msqrcv(td->td_ucred, msqkptr);
        if (error != 0)
                goto done2;
#endif

        msghdr = NULL;
        while (msghdr == NULL) {
                if (msgtyp == 0) {
                        msghdr = msqkptr->u.__msg_first;
                        if (msghdr != NULL) {
                                if (msgsz < msghdr->msg_ts &&
                                    (msgflg & MSG_NOERROR) == 0) {
                                        DPRINTF(("first message on the queue "
                                            "is too big (want %zu, got %d)\n",
                                            msgsz, msghdr->msg_ts));
                                        error = E2BIG;
                                        goto done2;
                                }
#ifdef MAC
                                error = mac_sysvmsq_check_msgrcv(td->td_ucred,
                                    msghdr);
                                if (error != 0)
                                        goto done2;
#endif
                                if (msqkptr->u.__msg_first ==
                                    msqkptr->u.__msg_last) {
                                        msqkptr->u.__msg_first = NULL;
                                        msqkptr->u.__msg_last = NULL;
                                } else {
                                        msqkptr->u.__msg_first = msghdr->msg_next;
                                        if (msqkptr->u.__msg_first == NULL)
                                                panic("msg_first/last screwed up #1");
                                }
                        }
                } else {
                        struct msg *previous;
                        struct msg **prev;

                        previous = NULL;
                        prev = &(msqkptr->u.__msg_first);
                        while ((msghdr = *prev) != NULL) {
                                /*
                                 * Is this message's type an exact match or is
                                 * this message's type less than or equal to
                                 * the absolute value of a negative msgtyp?
                                 * Note that the second half of this test can
                                 * NEVER be true if msgtyp is positive since
                                 * msg_type is always positive!
                                 */

                                if (msgtyp == msghdr->msg_type ||
                                    msghdr->msg_type <= -msgtyp) {
                                        DPRINTF(("found message type %ld, "
                                            "requested %ld\n",
                                            msghdr->msg_type, msgtyp));
                                        if (msgsz < msghdr->msg_ts &&
                                            (msgflg & MSG_NOERROR) == 0) {
                                                DPRINTF(("requested message "
                                                    "on the queue is too big "
                                                    "(want %zu, got %hu)\n",
                                                    msgsz, msghdr->msg_ts));
                                                error = E2BIG;
                                                goto done2;
                                        }
#ifdef MAC
                                        error = mac_sysvmsq_check_msgrcv(
                                            td->td_ucred, msghdr);
                                        if (error != 0)
                                                goto done2;
#endif
                                        *prev = msghdr->msg_next;
                                        if (msghdr == msqkptr->u.__msg_last) {
                                                if (previous == NULL) {
                                                        if (prev !=
                                                            &msqkptr->u.__msg_first)
                                                                panic("__msg_first/last screwed up #2");
                                                        msqkptr->u.__msg_first =
                                                            NULL;
                                                        msqkptr->u.__msg_last =
                                                            NULL;
                                                } else {
                                                        if (prev ==
                                                            &msqkptr->u.__msg_first)
                                                                panic("__msg_first/last screwed up #3");
                                                        msqkptr->u.__msg_last =
                                                            previous;
                                                }
                                        }
                                        break;
                                }
                                previous = msghdr;
                                prev = &(msghdr->msg_next);
                        }
                }

                /*
                 * We've either extracted the msghdr for the appropriate
                 * message or there isn't one.
                 * If there is one then bail out of this loop.
                 */

                if (msghdr != NULL)
                        break;

                /*
                 * Hmph!  No message found.  Does the user want to wait?
                 */

                if ((msgflg & IPC_NOWAIT) != 0) {
                        DPRINTF(("no appropriate message found (msgtyp=%ld)\n",
                            msgtyp));
                        /* The SVID says to return ENOMSG. */
                        error = ENOMSG;
                        goto done2;
                }

                /*
                 * Wait for something to happen
                 */

                DPRINTF(("msgrcv:  goodnight\n"));
                error = msleep(msqkptr, &msq_mtx, PVFS | PCATCH,
                    "msgrcv", 0);
                DPRINTF(("msgrcv:  good morning (error=%d)\n", error));

                if (error != 0) {
                        DPRINTF(("msgrcv:  interrupted system call\n"));
                        error = EINTR;
                        goto done2;
                }

                /*
                 * Make sure that the msq queue still exists
                 */

                if (msqkptr->u.msg_qbytes == 0 ||
                    msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
                        DPRINTF(("msqid deleted\n"));
                        error = EIDRM;
                        goto done2;
                }
        }

        /*
         * Return the message to the user.
         *
         * First, do the bookkeeping (before we risk being interrupted).
         */

        msqkptr->u.msg_cbytes -= msghdr->msg_ts;
        msqkptr->u.msg_qnum--;
        msqkptr->u.msg_lrpid = td->td_proc->p_pid;
        msqkptr->u.msg_rtime = time_second;

        racct_sub_cred(msqkptr->cred, RACCT_MSGQQUEUED, 1);
        racct_sub_cred(msqkptr->cred, RACCT_MSGQSIZE, msghdr->msg_ts);

        /*
         * Make msgsz the actual amount that we'll be returning.
         * Note that this effectively truncates the message if it is too long
         * (since msgsz is never increased).
         */

        DPRINTF(("found a message, msgsz=%zu, msg_ts=%hu\n", msgsz,
            msghdr->msg_ts));
        if (msgsz > msghdr->msg_ts)
                msgsz = msghdr->msg_ts;
        *mtype = msghdr->msg_type;

        /*
         * Return the segments to the user
         */

        next = msghdr->msg_spot;
        for (len = 0; len < msgsz; len += msginfo.msgssz) {
                size_t tlen;

                if (msgsz - len > msginfo.msgssz)
                        tlen = msginfo.msgssz;
                else
                        tlen = msgsz - len;
                if (next <= -1)
                        panic("next too low #3");
                if (next >= msginfo.msgseg)
                        panic("next out of range #3");
                mtx_unlock(&msq_mtx);
                error = copyout(&msgpool[next * msginfo.msgssz], msgp, tlen);
                mtx_lock(&msq_mtx);
                if (error != 0) {
                        DPRINTF(("error (%d) copying out message segment\n",
                            error));
                        msg_freehdr(msghdr);
                        wakeup(msqkptr);
                        goto done2;
                }
                msgp = (char *)msgp + tlen;
                next = msgmaps[next].next;
        }

        /*
         * Done, return the actual number of bytes copied out.
         */

        msg_freehdr(msghdr);
        wakeup(msqkptr);
        td->td_retval[0] = msgsz;
done2:
        mtx_unlock(&msq_mtx);
        return (error);
}

int
sys_msgrcv(struct thread *td, struct msgrcv_args *uap)
{
        int error;
        long mtype;

        DPRINTF(("call to msgrcv(%d, %p, %zu, %ld, %d)\n", uap->msqid,
            uap->msgp, uap->msgsz, uap->msgtyp, uap->msgflg));

        if ((error = kern_msgrcv(td, uap->msqid,
            (char *)uap->msgp + sizeof(mtype), uap->msgsz,
            uap->msgtyp, uap->msgflg, &mtype)) != 0)
                return (error);
        if ((error = copyout(&mtype, uap->msgp, sizeof(mtype))) != 0)
                DPRINTF(("error %d copying the message type\n", error));
        return (error);
}

static int
sysctl_msqids(SYSCTL_HANDLER_ARGS)
{
        struct msqid_kernel tmsqk;
#ifdef COMPAT_FREEBSD32
        struct msqid_kernel32 tmsqk32;
#endif
        struct prison *pr, *rpr;
        void *outaddr;
        size_t outsize;
        int error, i;

        pr = req->td->td_ucred->cr_prison;
        rpr = msg_find_prison(req->td->td_ucred);
        error = 0;
        for (i = 0; i < msginfo.msgmni; i++) {
                mtx_lock(&msq_mtx);
                if (msqids[i].u.msg_qbytes == 0 || rpr == NULL ||
                    msq_prison_cansee(rpr, &msqids[i]) != 0)
                        bzero(&tmsqk, sizeof(tmsqk));
                else {
                        tmsqk = msqids[i];
                        if (tmsqk.cred->cr_prison != pr)
                                tmsqk.u.msg_perm.key = IPC_PRIVATE;
                }
                mtx_unlock(&msq_mtx);
#ifdef COMPAT_FREEBSD32
                if (SV_CURPROC_FLAG(SV_ILP32)) {
                        bzero(&tmsqk32, sizeof(tmsqk32));
                        freebsd32_ipcperm_out(&tmsqk.u.msg_perm,
                            &tmsqk32.u.msg_perm);
                        /* Don't copy u.msg_first or u.msg_last */
                        CP(tmsqk, tmsqk32, u.msg_cbytes);
                        CP(tmsqk, tmsqk32, u.msg_qnum);
                        CP(tmsqk, tmsqk32, u.msg_qbytes);
                        CP(tmsqk, tmsqk32, u.msg_lspid);
                        CP(tmsqk, tmsqk32, u.msg_lrpid);
                        CP(tmsqk, tmsqk32, u.msg_stime);
                        CP(tmsqk, tmsqk32, u.msg_rtime);
                        CP(tmsqk, tmsqk32, u.msg_ctime);
                        /* Don't copy label or cred */
                        outaddr = &tmsqk32;
                        outsize = sizeof(tmsqk32);
                } else
#endif
                {
                        /* Don't leak kernel pointers */
                        tmsqk.u.__msg_first = NULL;
                        tmsqk.u.__msg_last = NULL;
                        tmsqk.label = NULL;
                        tmsqk.cred = NULL;
                        /*
                         * XXX: some padding also exists, but we take care to
                         * allocate our pool of msqid_kernel structs with
                         * zeroed memory so this should be OK.
                         */
                        outaddr = &tmsqk;
                        outsize = sizeof(tmsqk);
                }
                error = SYSCTL_OUT(req, outaddr, outsize);
                if (error != 0)
                        break;
        }
        return (error);
}

int
kern_get_msqids(struct thread *td, struct msqid_kernel **res, size_t *sz)
{
        struct msqid_kernel *pmsqk;
        struct prison *pr, *rpr;
        int i, mi;

        *sz = mi = msginfo.msgmni;
        if (res == NULL)
                return (0);

        pr = td->td_ucred->cr_prison;
        rpr = msg_find_prison(td->td_ucred);
        *res = malloc(sizeof(struct msqid_kernel) * mi, M_TEMP, M_WAITOK);
        for (i = 0; i < mi; i++) {
                pmsqk = &(*res)[i];
                mtx_lock(&msq_mtx);
                if (msqids[i].u.msg_qbytes == 0 || rpr == NULL ||
                    msq_prison_cansee(rpr, &msqids[i]) != 0)
                        bzero(pmsqk, sizeof(*pmsqk));
                else {
                        *pmsqk = msqids[i];
                        if (pmsqk->cred->cr_prison != pr)
                                pmsqk->u.msg_perm.key = IPC_PRIVATE;
                }
                mtx_unlock(&msq_mtx);
                pmsqk->u.__msg_first = NULL;
                pmsqk->u.__msg_last = NULL;
                pmsqk->label = NULL;
                pmsqk->cred = NULL;
        }
        return (0);
}

SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0,
    "Maximum message size");
SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0,
    "Number of message queue identifiers");
SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0,
    "Maximum number of bytes in a queue");
SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0,
    "Maximum number of messages in the system");
SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0,
    "Size of a message segment");
SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0,
    "Number of message segments");
SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids,
    CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
    NULL, 0, sysctl_msqids, "",
    "Array of struct msqid_kernel for each potential message queue");

static int
msg_prison_check(void *obj, void *data)
{
        struct prison *pr = obj;
        struct prison *prpr;
        struct vfsoptlist *opts = data;
        int error, jsys;

        /*
         * sysvmsg is a jailsys integer.
         * It must be "disable" if the parent jail is disabled.
         */
        error = vfs_copyopt(opts, "sysvmsg", &jsys, sizeof(jsys));
        if (error != ENOENT) {
                if (error != 0)
                        return (error);
                switch (jsys) {
                case JAIL_SYS_DISABLE:
                        break;
                case JAIL_SYS_NEW:
                case JAIL_SYS_INHERIT:
                        prison_lock(pr->pr_parent);
                        prpr = osd_jail_get(pr->pr_parent, msg_prison_slot);
                        prison_unlock(pr->pr_parent);
                        if (prpr == NULL)
                                return (EPERM);
                        break;
                default:
                        return (EINVAL);
                }
        }

        return (0);
}

static int
msg_prison_set(void *obj, void *data)
{
        struct prison *pr = obj;
        struct prison *tpr, *orpr, *nrpr, *trpr;
        struct vfsoptlist *opts = data;
        void *rsv;
        int jsys, descend;

        /*
         * sysvmsg controls which jail is the root of the associated msgs (this
         * jail or same as the parent), or if the feature is available at all.
         */
        if (vfs_copyopt(opts, "sysvmsg", &jsys, sizeof(jsys)) == ENOENT)
                jsys = vfs_flagopt(opts, "allow.sysvipc", NULL, 0)
                    ? JAIL_SYS_INHERIT
                    : vfs_flagopt(opts, "allow.nosysvipc", NULL, 0)
                    ? JAIL_SYS_DISABLE
                    : -1;
        if (jsys == JAIL_SYS_DISABLE) {
                prison_lock(pr);
                orpr = osd_jail_get(pr, msg_prison_slot);
                if (orpr != NULL)
                        osd_jail_del(pr, msg_prison_slot);
                prison_unlock(pr);
                if (orpr != NULL) {
                        if (orpr == pr)
                                msg_prison_cleanup(pr);
                        /* Disable all child jails as well. */
                        FOREACH_PRISON_DESCENDANT(pr, tpr, descend) {
                                prison_lock(tpr);
                                trpr = osd_jail_get(tpr, msg_prison_slot);
                                if (trpr != NULL) {
                                        osd_jail_del(tpr, msg_prison_slot);
                                        prison_unlock(tpr);
                                        if (trpr == tpr)
                                                msg_prison_cleanup(tpr);
                                } else {
                                        prison_unlock(tpr);
                                        descend = 0;
                                }
                        }
                }
        } else if (jsys != -1) {
                if (jsys == JAIL_SYS_NEW)
                        nrpr = pr;
                else {
                        prison_lock(pr->pr_parent);
                        nrpr = osd_jail_get(pr->pr_parent, msg_prison_slot);
                        prison_unlock(pr->pr_parent);
                }
                rsv = osd_reserve(msg_prison_slot);
                prison_lock(pr);
                orpr = osd_jail_get(pr, msg_prison_slot);
                if (orpr != nrpr)
                        (void)osd_jail_set_reserved(pr, msg_prison_slot, rsv,
                            nrpr);
                else
                        osd_free_reserved(rsv);
                prison_unlock(pr);
                if (orpr != nrpr) {
                        if (orpr == pr)
                                msg_prison_cleanup(pr);
                        if (orpr != NULL) {
                                /* Change child jails matching the old root, */
                                FOREACH_PRISON_DESCENDANT(pr, tpr, descend) {
                                        prison_lock(tpr);
                                        trpr = osd_jail_get(tpr,
                                            msg_prison_slot);
                                        if (trpr == orpr) {
                                                (void)osd_jail_set(tpr,
                                                    msg_prison_slot, nrpr);
                                                prison_unlock(tpr);
                                                if (trpr == tpr)
                                                        msg_prison_cleanup(tpr);
                                        } else {
                                                prison_unlock(tpr);
                                                descend = 0;
                                        }
                                }
                        }
                }
        }

        return (0);
}

static int
msg_prison_get(void *obj, void *data)
{
        struct prison *pr = obj;
        struct prison *rpr;
        struct vfsoptlist *opts = data;
        int error, jsys;

        /* Set sysvmsg based on the jail's root prison. */
        prison_lock(pr);
        rpr = osd_jail_get(pr, msg_prison_slot);
        prison_unlock(pr);
        jsys = rpr == NULL ? JAIL_SYS_DISABLE
            : rpr == pr ? JAIL_SYS_NEW : JAIL_SYS_INHERIT;
        error = vfs_setopt(opts, "sysvmsg", &jsys, sizeof(jsys));
        if (error == ENOENT)
                error = 0;
        return (error);
}

static int
msg_prison_remove(void *obj, void *data __unused)
{
        struct prison *pr = obj;
        struct prison *rpr;

        prison_lock(pr);
        rpr = osd_jail_get(pr, msg_prison_slot);
        prison_unlock(pr);
        if (rpr == pr)
                msg_prison_cleanup(pr);
        return (0);
}

static void
msg_prison_cleanup(struct prison *pr)
{
        struct msqid_kernel *msqkptr;
        int i;

        /* Remove any msqs that belong to this jail. */
        mtx_lock(&msq_mtx);
        for (i = 0; i < msginfo.msgmni; i++) {
                msqkptr = &msqids[i];
                if (msqkptr->u.msg_qbytes != 0 &&
                    msqkptr->cred != NULL && msqkptr->cred->cr_prison == pr)
                        msq_remove(msqkptr);
        }
        mtx_unlock(&msq_mtx);
}

SYSCTL_JAIL_PARAM_SYS_NODE(sysvmsg, CTLFLAG_RW, "SYSV message queues");

#ifdef COMPAT_FREEBSD32
int
freebsd32_msgsys(struct thread *td, struct freebsd32_msgsys_args *uap)
{

#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
    defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
        AUDIT_ARG_SVIPC_WHICH(uap->which);
        switch (uap->which) {
        case 0:
                return (freebsd7_freebsd32_msgctl(td,
                    (struct freebsd7_freebsd32_msgctl_args *)&uap->a2));
        case 2:
                return (freebsd32_msgsnd(td,
                    (struct freebsd32_msgsnd_args *)&uap->a2));
        case 3:
                return (freebsd32_msgrcv(td,
                    (struct freebsd32_msgrcv_args *)&uap->a2));
        default:
                return (sys_msgsys(td, (struct msgsys_args *)uap));
        }
#else
        return (kern_nosys(td, 0));
#endif
}

#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
    defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
int
freebsd7_freebsd32_msgctl(struct thread *td,
    struct freebsd7_freebsd32_msgctl_args *uap)
{
        struct msqid_ds msqbuf;
        struct msqid_ds_old32 msqbuf32;
        int error;

        if (uap->cmd == IPC_SET) {
                error = copyin(uap->buf, &msqbuf32, sizeof(msqbuf32));
                if (error)
                        return (error);
                freebsd32_ipcperm_old_in(&msqbuf32.msg_perm, &msqbuf.msg_perm);
                PTRIN_CP(msqbuf32, msqbuf, __msg_first);
                PTRIN_CP(msqbuf32, msqbuf, __msg_last);
                CP(msqbuf32, msqbuf, msg_cbytes);
                CP(msqbuf32, msqbuf, msg_qnum);
                CP(msqbuf32, msqbuf, msg_qbytes);
                CP(msqbuf32, msqbuf, msg_lspid);
                CP(msqbuf32, msqbuf, msg_lrpid);
                CP(msqbuf32, msqbuf, msg_stime);
                CP(msqbuf32, msqbuf, msg_rtime);
                CP(msqbuf32, msqbuf, msg_ctime);
        }
        error = kern_msgctl(td, uap->msqid, uap->cmd, &msqbuf);
        if (error)
                return (error);
        if (uap->cmd == IPC_STAT) {
                bzero(&msqbuf32, sizeof(msqbuf32));
                freebsd32_ipcperm_old_out(&msqbuf.msg_perm, &msqbuf32.msg_perm);
                PTROUT_CP(msqbuf, msqbuf32, __msg_first);
                PTROUT_CP(msqbuf, msqbuf32, __msg_last);
                CP(msqbuf, msqbuf32, msg_cbytes);
                CP(msqbuf, msqbuf32, msg_qnum);
                CP(msqbuf, msqbuf32, msg_qbytes);
                CP(msqbuf, msqbuf32, msg_lspid);
                CP(msqbuf, msqbuf32, msg_lrpid);
                CP(msqbuf, msqbuf32, msg_stime);
                CP(msqbuf, msqbuf32, msg_rtime);
                CP(msqbuf, msqbuf32, msg_ctime);
                error = copyout(&msqbuf32, uap->buf, sizeof(struct msqid_ds32));
        }
        return (error);
}
#endif

int
freebsd32_msgctl(struct thread *td, struct freebsd32_msgctl_args *uap)
{
        struct msqid_ds msqbuf;
        struct msqid_ds32 msqbuf32;
        int error;

        if (uap->cmd == IPC_SET) {
                error = copyin(uap->buf, &msqbuf32, sizeof(msqbuf32));
                if (error)
                        return (error);
                freebsd32_ipcperm_in(&msqbuf32.msg_perm, &msqbuf.msg_perm);
                PTRIN_CP(msqbuf32, msqbuf, __msg_first);
                PTRIN_CP(msqbuf32, msqbuf, __msg_last);
                CP(msqbuf32, msqbuf, msg_cbytes);
                CP(msqbuf32, msqbuf, msg_qnum);
                CP(msqbuf32, msqbuf, msg_qbytes);
                CP(msqbuf32, msqbuf, msg_lspid);
                CP(msqbuf32, msqbuf, msg_lrpid);
                CP(msqbuf32, msqbuf, msg_stime);
                CP(msqbuf32, msqbuf, msg_rtime);
                CP(msqbuf32, msqbuf, msg_ctime);
        }
        error = kern_msgctl(td, uap->msqid, uap->cmd, &msqbuf);
        if (error)
                return (error);
        if (uap->cmd == IPC_STAT) {
                freebsd32_ipcperm_out(&msqbuf.msg_perm, &msqbuf32.msg_perm);
                PTROUT_CP(msqbuf, msqbuf32, __msg_first);
                PTROUT_CP(msqbuf, msqbuf32, __msg_last);
                CP(msqbuf, msqbuf32, msg_cbytes);
                CP(msqbuf, msqbuf32, msg_qnum);
                CP(msqbuf, msqbuf32, msg_qbytes);
                CP(msqbuf, msqbuf32, msg_lspid);
                CP(msqbuf, msqbuf32, msg_lrpid);
                CP(msqbuf, msqbuf32, msg_stime);
                CP(msqbuf, msqbuf32, msg_rtime);
                CP(msqbuf, msqbuf32, msg_ctime);
                error = copyout(&msqbuf32, uap->buf, sizeof(struct msqid_ds32));
        }
        return (error);
}

int
freebsd32_msgsnd(struct thread *td, struct freebsd32_msgsnd_args *uap)
{
        const void *msgp;
        long mtype;
        int32_t mtype32;
        int error;

        msgp = PTRIN(uap->msgp);
        if ((error = copyin(msgp, &mtype32, sizeof(mtype32))) != 0)
                return (error);
        mtype = mtype32;
        return (kern_msgsnd(td, uap->msqid,
            (const char *)msgp + sizeof(mtype32),
            uap->msgsz, uap->msgflg, mtype));
}

int
freebsd32_msgrcv(struct thread *td, struct freebsd32_msgrcv_args *uap)
{
        void *msgp;
        long mtype;
        int32_t mtype32;
        int error;

        msgp = PTRIN(uap->msgp);
        if ((error = kern_msgrcv(td, uap->msqid,
            (char *)msgp + sizeof(mtype32), uap->msgsz,
            uap->msgtyp, uap->msgflg, &mtype)) != 0)
                return (error);
        mtype32 = (int32_t)mtype;
        return (copyout(&mtype32, msgp, sizeof(mtype32)));
}
#endif

#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
    defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)

/* XXX casting to (sy_call_t *) is bogus, as usual. */
static sy_call_t *msgcalls[] = {
        (sy_call_t *)freebsd7_msgctl, (sy_call_t *)sys_msgget,
        (sy_call_t *)sys_msgsnd, (sy_call_t *)sys_msgrcv
};

/*
 * Entry point for all MSG calls.
 *
 * XXX actually varargs.
 * struct msgsys_args {
 *              int     which;
 *              int     a2;
 *              int     a3;
 *              int     a4;
 *              int     a5;
 *              int     a6;
 *      } *uap;
 */
int
sys_msgsys(struct thread *td, struct msgsys_args *uap)
{
        int error;

        AUDIT_ARG_SVIPC_WHICH(uap->which);
        if (uap->which < 0 || uap->which >= nitems(msgcalls))
                return (EINVAL);
        error = (*msgcalls[uap->which])(td, &uap->a2);
        return (error);
}

#ifndef CP
#define CP(src, dst, fld)       do { (dst).fld = (src).fld; } while (0)
#endif

#ifndef _SYS_SYSPROTO_H_
struct freebsd7_msgctl_args {
        int     msqid;
        int     cmd;
        struct  msqid_ds_old *buf;
};
#endif
int
freebsd7_msgctl(struct thread *td, struct freebsd7_msgctl_args *uap)
{
        struct msqid_ds_old msqold;
        struct msqid_ds msqbuf;
        int error;

        DPRINTF(("call to freebsd7_msgctl(%d, %d, %p)\n", uap->msqid, uap->cmd,
            uap->buf));
        if (uap->cmd == IPC_SET) {
                error = copyin(uap->buf, &msqold, sizeof(msqold));
                if (error)
                        return (error);
                ipcperm_old2new(&msqold.msg_perm, &msqbuf.msg_perm);
                CP(msqold, msqbuf, __msg_first);
                CP(msqold, msqbuf, __msg_last);
                CP(msqold, msqbuf, msg_cbytes);
                CP(msqold, msqbuf, msg_qnum);
                CP(msqold, msqbuf, msg_qbytes);
                CP(msqold, msqbuf, msg_lspid);
                CP(msqold, msqbuf, msg_lrpid);
                CP(msqold, msqbuf, msg_stime);
                CP(msqold, msqbuf, msg_rtime);
                CP(msqold, msqbuf, msg_ctime);
        }
        error = kern_msgctl(td, uap->msqid, uap->cmd, &msqbuf);
        if (error)
                return (error);
        if (uap->cmd == IPC_STAT) {
                bzero(&msqold, sizeof(msqold));
                ipcperm_new2old(&msqbuf.msg_perm, &msqold.msg_perm);
                CP(msqbuf, msqold, __msg_first);
                CP(msqbuf, msqold, __msg_last);
                CP(msqbuf, msqold, msg_cbytes);
                CP(msqbuf, msqold, msg_qnum);
                CP(msqbuf, msqold, msg_qbytes);
                CP(msqbuf, msqold, msg_lspid);
                CP(msqbuf, msqold, msg_lrpid);
                CP(msqbuf, msqold, msg_stime);
                CP(msqbuf, msqold, msg_rtime);
                CP(msqbuf, msqold, msg_ctime);
                error = copyout(&msqold, uap->buf, sizeof(struct msqid_ds_old));
        }
        return (error);
}

#undef CP

#endif  /* COMPAT_FREEBSD4 || COMPAT_FREEBSD5 || COMPAT_FREEBSD6 ||
           COMPAT_FREEBSD7 */