/*-
 * Copyright (c) 2014 John Baldwin
 * Copyright (c) 2014, 2016 The FreeBSD Foundation
 *
 * Portions of this software were developed by Konstantin Belousov
 * under sponsorship from the FreeBSD Foundation.
 *
 * 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_ktrace.h"

#include <sys/param.h>
#include <sys/_unrhdr.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/procctl.h>
#include <sys/sx.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/wait.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_extern.h>

static int
protect_setchild(struct thread *td, struct proc *p, int flags)
{

        PROC_LOCK_ASSERT(p, MA_OWNED);
        if (p->p_flag & P_SYSTEM || p_cansched(td, p) != 0)
                return (0);
        if (flags & PPROT_SET) {
                p->p_flag |= P_PROTECTED;
                if (flags & PPROT_INHERIT)
                        p->p_flag2 |= P2_INHERIT_PROTECTED;
        } else {
                p->p_flag &= ~P_PROTECTED;
                p->p_flag2 &= ~P2_INHERIT_PROTECTED;
        }
        return (1);
}

static int
protect_setchildren(struct thread *td, struct proc *top, int flags)
{
        struct proc *p;
        int ret;

        p = top;
        ret = 0;
        sx_assert(&proctree_lock, SX_LOCKED);
        for (;;) {
                ret |= protect_setchild(td, p, flags);
                PROC_UNLOCK(p);
                /*
                 * If this process has children, descend to them next,
                 * otherwise do any siblings, and if done with this level,
                 * follow back up the tree (but not past top).
                 */
                if (!LIST_EMPTY(&p->p_children))
                        p = LIST_FIRST(&p->p_children);
                else for (;;) {
                        if (p == top) {
                                PROC_LOCK(p);
                                return (ret);
                        }
                        if (LIST_NEXT(p, p_sibling)) {
                                p = LIST_NEXT(p, p_sibling);
                                break;
                        }
                        p = p->p_pptr;
                }
                PROC_LOCK(p);
        }
}

static int
protect_set(struct thread *td, struct proc *p, void *data)
{
        int error, flags, ret;

        flags = *(int *)data;
        switch (PPROT_OP(flags)) {
        case PPROT_SET:
        case PPROT_CLEAR:
                break;
        default:
                return (EINVAL);
        }

        if ((PPROT_FLAGS(flags) & ~(PPROT_DESCEND | PPROT_INHERIT)) != 0)
                return (EINVAL);

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

        if (flags & PPROT_DESCEND)
                ret = protect_setchildren(td, p, flags);
        else
                ret = protect_setchild(td, p, flags);
        if (ret == 0)
                return (EPERM);
        return (0);
}

static int
reap_acquire(struct thread *td, struct proc *p, void *data __unused)
{

        sx_assert(&proctree_lock, SX_XLOCKED);
        if (p != td->td_proc)
                return (EPERM);
        if ((p->p_treeflag & P_TREE_REAPER) != 0)
                return (EBUSY);
        p->p_treeflag |= P_TREE_REAPER;
        /*
         * We do not reattach existing children and the whole tree
         * under them to us, since p->p_reaper already seen them.
         */
        return (0);
}

static int
reap_release(struct thread *td, struct proc *p, void *data __unused)
{

        sx_assert(&proctree_lock, SX_XLOCKED);
        if (p != td->td_proc)
                return (EPERM);
        if (p == initproc)
                return (EINVAL);
        if ((p->p_treeflag & P_TREE_REAPER) == 0)
                return (EINVAL);
        reaper_abandon_children(p, false);
        return (0);
}

static int
reap_status(struct thread *td, struct proc *p, void *data)
{
        struct proc *reap, *p2, *first_p;
        struct procctl_reaper_status *rs;

        rs = data;
        sx_assert(&proctree_lock, SX_LOCKED);
        if ((p->p_treeflag & P_TREE_REAPER) == 0) {
                reap = p->p_reaper;
        } else {
                reap = p;
                rs->rs_flags |= REAPER_STATUS_OWNED;
        }
        if (reap == initproc)
                rs->rs_flags |= REAPER_STATUS_REALINIT;
        rs->rs_reaper = reap->p_pid;
        rs->rs_descendants = 0;
        rs->rs_children = 0;
        if (!LIST_EMPTY(&reap->p_reaplist)) {
                first_p = LIST_FIRST(&reap->p_children);
                if (first_p == NULL)
                        first_p = LIST_FIRST(&reap->p_reaplist);
                rs->rs_pid = first_p->p_pid;
                LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
                        if (proc_realparent(p2) == reap)
                                rs->rs_children++;
                        rs->rs_descendants++;
                }
        } else {
                rs->rs_pid = -1;
        }
        return (0);
}

static int
reap_getpids(struct thread *td, struct proc *p, void *data)
{
        struct proc *reap, *p2;
        struct procctl_reaper_pidinfo *pi, *pip;
        struct procctl_reaper_pids *rp;
        u_int i, n;
        int error;

        rp = data;
        sx_assert(&proctree_lock, SX_LOCKED);
        PROC_UNLOCK(p);
        reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
        n = i = 0;
        error = 0;
        LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling)
                n++;
        sx_unlock(&proctree_lock);
        if (rp->rp_count < n)
                n = rp->rp_count;
        pi = malloc(n * sizeof(*pi), M_TEMP, M_WAITOK);
        sx_slock(&proctree_lock);
        LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
                if (i == n)
                        break;
                pip = &pi[i];
                bzero(pip, sizeof(*pip));
                pip->pi_pid = p2->p_pid;
                pip->pi_subtree = p2->p_reapsubtree;
                pip->pi_flags = REAPER_PIDINFO_VALID;
                if (proc_realparent(p2) == reap)
                        pip->pi_flags |= REAPER_PIDINFO_CHILD;
                if ((p2->p_treeflag & P_TREE_REAPER) != 0)
                        pip->pi_flags |= REAPER_PIDINFO_REAPER;
                if ((p2->p_flag & P_STOPPED) != 0)
                        pip->pi_flags |= REAPER_PIDINFO_STOPPED;
                if (p2->p_state == PRS_ZOMBIE)
                        pip->pi_flags |= REAPER_PIDINFO_ZOMBIE;
                else if ((p2->p_flag & P_WEXIT) != 0)
                        pip->pi_flags |= REAPER_PIDINFO_EXITING;
                i++;
        }
        sx_sunlock(&proctree_lock);
        error = copyout(pi, rp->rp_pids, i * sizeof(*pi));
        free(pi, M_TEMP);
        sx_slock(&proctree_lock);
        PROC_LOCK(p);
        return (error);
}

struct reap_kill_proc_work {
        struct ucred *cr;
        struct proc *target;
        ksiginfo_t *ksi;
        struct procctl_reaper_kill *rk;
        int *error;
};

static void
reap_kill_proc_locked(struct reap_kill_proc_work *w)
{
        int error;

        PROC_LOCK_ASSERT(w->target, MA_OWNED);
        PROC_ASSERT_HELD(w->target);

        error = cr_cansignal(w->cr, w->target, w->rk->rk_sig);
        if (error != 0) {
                /*
                 * Hide ESRCH errors to ensure that this function
                 * cannot be used as an oracle for process visibility.
                 */
                if (error != ESRCH && *w->error == 0) {
                        w->rk->rk_fpid = w->target->p_pid;
                        *w->error = error;
                }
                return;
        }

        (void)pksignal(w->target, w->rk->rk_sig, w->ksi);
        w->rk->rk_killed++;
        *w->error = error;
}

static void
reap_kill_proc(struct reap_kill_proc_work *w, bool *proctree_dropped)
{
        struct pgrp *pgrp;
        int xlocked;

        sx_assert(&proctree_lock, SX_LOCKED);
        xlocked = sx_xlocked(&proctree_lock);
        PROC_LOCK_ASSERT(w->target, MA_OWNED);
        PROC_ASSERT_HELD(w->target);

        /* Sync with forks. */
        for (;;) {
                /*
                 * Short-circuit handling of the exiting process, do
                 * not wait for it to single-thread (hold prevents it
                 * from exiting further).  This avoids
                 * locking pg_killsx for it, and reduces the
                 * proctree_lock contention.
                 */
                if ((w->target->p_flag2 & P2_WEXIT) != 0)
                        return;

                pgrp = w->target->p_pgrp;
                if (pgrp == NULL || sx_try_xlock(&pgrp->pg_killsx))
                        break;

                PROC_UNLOCK(w->target);
                sx_unlock(&proctree_lock);
                /* This is safe because pgrp zone is nofree. */
                sx_xlock(&pgrp->pg_killsx);
                sx_xunlock(&pgrp->pg_killsx);
                *proctree_dropped = true;
                if (xlocked)
                        sx_xlock(&proctree_lock);
                else
                        sx_slock(&proctree_lock);
                PROC_LOCK(w->target);
        }

        reap_kill_proc_locked(w);

        if (pgrp != NULL)
                sx_xunlock(&pgrp->pg_killsx);
}

struct reap_kill_tracker {
        struct proc *parent;
        TAILQ_ENTRY(reap_kill_tracker) link;
};

TAILQ_HEAD(reap_kill_tracker_head, reap_kill_tracker);

static void
reap_kill_sched(struct reap_kill_tracker_head *tracker, struct proc *p2)
{
        struct reap_kill_tracker *t;

        PROC_LOCK(p2);
        if ((p2->p_flag2 & P2_WEXIT) != 0) {
                PROC_UNLOCK(p2);
                return;
        }
        _PHOLD(p2);
        PROC_UNLOCK(p2);
        t = malloc(sizeof(struct reap_kill_tracker), M_TEMP, M_WAITOK);
        t->parent = p2;
        TAILQ_INSERT_TAIL(tracker, t, link);
}

static void
reap_kill_sched_free(struct reap_kill_tracker *t)
{
        PRELE(t->parent);
        free(t, M_TEMP);
}

static void
reap_kill_children(struct thread *td, struct proc *reaper,
    struct procctl_reaper_kill *rk, ksiginfo_t *ksi, int *error)
{
        struct proc *p2;
        int error1;

        LIST_FOREACH(p2, &reaper->p_children, p_sibling) {
                PROC_LOCK(p2);
                if ((p2->p_flag2 & P2_WEXIT) == 0) {
                        error1 = p_cansignal(td, p2, rk->rk_sig);
                        if (error1 != 0) {
                                if (*error == ESRCH) {
                                        rk->rk_fpid = p2->p_pid;
                                        *error = error1;
                                }

                                /*
                                 * Do not end the loop on error,
                                 * signal everything we can.
                                 */
                        } else {
                                (void)pksignal(p2, rk->rk_sig, ksi);
                                rk->rk_killed++;
                        }
                }
                PROC_UNLOCK(p2);
        }
}

static bool
reap_kill_subtree_once(struct thread *td, struct proc *p, struct proc *reaper,
    struct unrhdr *pids, struct reap_kill_proc_work *w)
{
        struct reap_kill_tracker_head tracker;
        struct reap_kill_tracker *t;
        struct proc *p2;
        bool proctree_dropped, res;

        res = false;
        TAILQ_INIT(&tracker);
        reap_kill_sched(&tracker, reaper);
        while ((t = TAILQ_FIRST(&tracker)) != NULL) {
                TAILQ_REMOVE(&tracker, t, link);

again:
                /*
                 * Since reap_kill_proc() drops proctree_lock sx, it
                 * is possible that the tracked reaper is no longer.
                 * In this case the subtree is reparented to the new
                 * reaper, which should handle it.
                 */
                if ((t->parent->p_treeflag & P_TREE_REAPER) == 0) {
                        reap_kill_sched_free(t);
                        res = true;
                        continue;
                }

                LIST_FOREACH(p2, &t->parent->p_reaplist, p_reapsibling) {
                        if (t->parent == reaper &&
                            (w->rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
                            p2->p_reapsubtree != w->rk->rk_subtree)
                                continue;
                        if ((p2->p_treeflag & P_TREE_REAPER) != 0)
                                reap_kill_sched(&tracker, p2);

                        /*
                         * Handle possible pid reuse.  If we recorded
                         * p2 as killed but its p_flag2 does not
                         * confirm it, that means that the process
                         * terminated and its id was reused by other
                         * process in the reaper subtree.
                         *
                         * Unlocked read of p2->p_flag2 is fine, it is
                         * our thread that set the tested flag.
                         */
                        if (alloc_unr_specific(pids, p2->p_pid) != p2->p_pid &&
                            (atomic_load_int(&p2->p_flag2) &
                            (P2_REAPKILLED | P2_WEXIT)) != 0)
                                continue;

                        proctree_dropped = false;
                        PROC_LOCK(p2);
                        if ((p2->p_flag2 & P2_WEXIT) == 0) {
                                _PHOLD(p2);

                                /*
                                 * sapblk ensures that only one thread
                                 * in the system sets this flag.
                                 */
                                p2->p_flag2 |= P2_REAPKILLED;

                                w->target = p2;
                                reap_kill_proc(w, &proctree_dropped);
                                _PRELE(p2);
                        }
                        PROC_UNLOCK(p2);
                        res = true;
                        if (proctree_dropped)
                                goto again;
                }
                reap_kill_sched_free(t);
        }
        return (res);
}

static void
reap_kill_subtree(struct thread *td, struct proc *p, struct proc *reaper,
    struct reap_kill_proc_work *w)
{
        struct unrhdr pids;
        void *ihandle;
        struct proc *p2;
        int pid;

        /*
         * pids records processes which were already signalled, to
         * avoid doubling signals to them if iteration needs to be
         * repeated.
         */
        init_unrhdr(&pids, 1, PID_MAX, UNR_NO_MTX);
        PROC_LOCK(td->td_proc);
        if ((td->td_proc->p_flag2 & P2_WEXIT) != 0) {
                PROC_UNLOCK(td->td_proc);
                goto out;
        }
        PROC_UNLOCK(td->td_proc);
        while (reap_kill_subtree_once(td, p, reaper, &pids, w))
               ;

        ihandle = create_iter_unr(&pids);
        while ((pid = next_iter_unr(ihandle)) != -1) {
                p2 = pfind(pid);
                if (p2 != NULL) {
                        p2->p_flag2 &= ~P2_REAPKILLED;
                        PROC_UNLOCK(p2);
                }
        }
        free_iter_unr(ihandle);

out:
        clean_unrhdr(&pids);
        clear_unrhdr(&pids);
}

static bool
reap_kill_sapblk(struct thread *td __unused, void *data)
{
        struct procctl_reaper_kill *rk;

        rk = data;
        return ((rk->rk_flags & REAPER_KILL_CHILDREN) == 0);
}

static int
reap_kill(struct thread *td, struct proc *p, void *data)
{
        struct reap_kill_proc_work w;
        struct proc *reaper;
        ksiginfo_t ksi;
        struct procctl_reaper_kill *rk;
        int error;

        rk = data;
        sx_assert(&proctree_lock, SX_LOCKED);
        if (CAP_TRACING(td))
                ktrcapfail(CAPFAIL_SIGNAL, &rk->rk_sig);
        if (IN_CAPABILITY_MODE(td))
                return (ECAPMODE);
        if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG ||
            (rk->rk_flags & ~(REAPER_KILL_CHILDREN |
            REAPER_KILL_SUBTREE)) != 0 || (rk->rk_flags &
            (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE)) ==
            (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE))
                return (EINVAL);
        PROC_UNLOCK(p);
        reaper = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
        ksiginfo_init(&ksi);
        ksi.ksi_signo = rk->rk_sig;
        ksi.ksi_code = SI_USER;
        ksi.ksi_pid = td->td_proc->p_pid;
        ksi.ksi_uid = td->td_ucred->cr_ruid;
        error = ESRCH;
        rk->rk_killed = 0;
        rk->rk_fpid = -1;
        if ((rk->rk_flags & REAPER_KILL_CHILDREN) != 0) {
                reap_kill_children(td, reaper, rk, &ksi, &error);
        } else {
                w.cr = crhold(td->td_ucred);
                w.ksi = &ksi;
                w.rk = rk;
                w.error = &error;
                reap_kill_subtree(td, p, reaper, &w);
                crfree(w.cr);
        }
        PROC_LOCK(p);
        return (error);
}

static int
trace_ctl(struct thread *td, struct proc *p, void *data)
{
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        state = *(int *)data;

        /*
         * Ktrace changes p_traceflag from or to zero under the
         * process lock, so the test does not need to acquire ktrace
         * mutex.
         */
        if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0)
                return (EBUSY);

        switch (state) {
        case PROC_TRACE_CTL_ENABLE:
                if (td->td_proc != p)
                        return (EPERM);
                p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC);
                break;
        case PROC_TRACE_CTL_DISABLE_EXEC:
                p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE;
                break;
        case PROC_TRACE_CTL_DISABLE:
                if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) {
                        KASSERT((p->p_flag2 & P2_NOTRACE) != 0,
                            ("dandling P2_NOTRACE_EXEC"));
                        if (td->td_proc != p)
                                return (EPERM);
                        p->p_flag2 &= ~P2_NOTRACE_EXEC;
                } else {
                        p->p_flag2 |= P2_NOTRACE;
                }
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

static int
trace_status(struct thread *td, struct proc *p, void *data)
{
        int *status;

        status = data;
        if ((p->p_flag2 & P2_NOTRACE) != 0) {
                KASSERT((p->p_flag & P_TRACED) == 0,
                    ("%d traced but tracing disabled", p->p_pid));
                *status = -1;
        } else if ((p->p_flag & P_TRACED) != 0) {
                *status = p->p_pptr->p_pid;
        } else {
                *status = 0;
        }
        return (0);
}

static int
trapcap_ctl(struct thread *td, struct proc *p, void *data)
{
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        state = *(int *)data;

        switch (state) {
        case PROC_TRAPCAP_CTL_ENABLE:
                p->p_flag2 |= P2_TRAPCAP;
                break;
        case PROC_TRAPCAP_CTL_DISABLE:
                p->p_flag2 &= ~P2_TRAPCAP;
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

static int
trapcap_status(struct thread *td, struct proc *p, void *data)
{
        int *status;

        status = data;
        *status = (p->p_flag2 & P2_TRAPCAP) != 0 ? PROC_TRAPCAP_CTL_ENABLE :
            PROC_TRAPCAP_CTL_DISABLE;
        return (0);
}

static int
no_new_privs_ctl(struct thread *td, struct proc *p, void *data)
{
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        state = *(int *)data;

        if (state != PROC_NO_NEW_PRIVS_ENABLE)
                return (EINVAL);
        p->p_flag2 |= P2_NO_NEW_PRIVS;
        return (0);
}

static int
no_new_privs_status(struct thread *td, struct proc *p, void *data)
{

        *(int *)data = (p->p_flag2 & P2_NO_NEW_PRIVS) != 0 ?
            PROC_NO_NEW_PRIVS_ENABLE : PROC_NO_NEW_PRIVS_DISABLE;
        return (0);
}

static int
protmax_ctl(struct thread *td, struct proc *p, void *data)
{
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        state = *(int *)data;

        switch (state) {
        case PROC_PROTMAX_FORCE_ENABLE:
                p->p_flag2 &= ~P2_PROTMAX_DISABLE;
                p->p_flag2 |= P2_PROTMAX_ENABLE;
                break;
        case PROC_PROTMAX_FORCE_DISABLE:
                p->p_flag2 |= P2_PROTMAX_DISABLE;
                p->p_flag2 &= ~P2_PROTMAX_ENABLE;
                break;
        case PROC_PROTMAX_NOFORCE:
                p->p_flag2 &= ~(P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE);
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

static int
protmax_status(struct thread *td, struct proc *p, void *data)
{
        int d;

        switch (p->p_flag2 & (P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE)) {
        case 0:
                d = PROC_PROTMAX_NOFORCE;
                break;
        case P2_PROTMAX_ENABLE:
                d = PROC_PROTMAX_FORCE_ENABLE;
                break;
        case P2_PROTMAX_DISABLE:
                d = PROC_PROTMAX_FORCE_DISABLE;
                break;
        }
        if (kern_mmap_maxprot(p, PROT_READ) == PROT_READ)
                d |= PROC_PROTMAX_ACTIVE;
        *(int *)data = d;
        return (0);
}

static int
aslr_ctl(struct thread *td, struct proc *p, void *data)
{
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        state = *(int *)data;

        switch (state) {
        case PROC_ASLR_FORCE_ENABLE:
                p->p_flag2 &= ~P2_ASLR_DISABLE;
                p->p_flag2 |= P2_ASLR_ENABLE;
                break;
        case PROC_ASLR_FORCE_DISABLE:
                p->p_flag2 |= P2_ASLR_DISABLE;
                p->p_flag2 &= ~P2_ASLR_ENABLE;
                break;
        case PROC_ASLR_NOFORCE:
                p->p_flag2 &= ~(P2_ASLR_ENABLE | P2_ASLR_DISABLE);
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

static int
aslr_status(struct thread *td, struct proc *p, void *data)
{
        struct vmspace *vm;
        int d;

        switch (p->p_flag2 & (P2_ASLR_ENABLE | P2_ASLR_DISABLE)) {
        case 0:
                d = PROC_ASLR_NOFORCE;
                break;
        case P2_ASLR_ENABLE:
                d = PROC_ASLR_FORCE_ENABLE;
                break;
        case P2_ASLR_DISABLE:
                d = PROC_ASLR_FORCE_DISABLE;
                break;
        }
        if ((p->p_flag & P_WEXIT) == 0) {
                _PHOLD(p);
                PROC_UNLOCK(p);
                vm = vmspace_acquire_ref(p);
                if (vm != NULL) {
                        if ((vm->vm_map.flags & MAP_ASLR) != 0)
                                d |= PROC_ASLR_ACTIVE;
                        vmspace_free(vm);
                }
                PROC_LOCK(p);
                _PRELE(p);
        }
        *(int *)data = d;
        return (0);
}

static int
stackgap_ctl(struct thread *td, struct proc *p, void *data)
{
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        state = *(int *)data;

        if ((state & ~(PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE |
            PROC_STACKGAP_ENABLE_EXEC | PROC_STACKGAP_DISABLE_EXEC)) != 0)
                return (EINVAL);
        switch (state & (PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE)) {
        case PROC_STACKGAP_ENABLE:
                if ((p->p_flag2 & P2_STKGAP_DISABLE) != 0)
                        return (EINVAL);
                break;
        case PROC_STACKGAP_DISABLE:
                p->p_flag2 |= P2_STKGAP_DISABLE;
                break;
        case 0:
                break;
        default:
                return (EINVAL);
        }
        switch (state & (PROC_STACKGAP_ENABLE_EXEC |
            PROC_STACKGAP_DISABLE_EXEC)) {
        case PROC_STACKGAP_ENABLE_EXEC:
                p->p_flag2 &= ~P2_STKGAP_DISABLE_EXEC;
                break;
        case PROC_STACKGAP_DISABLE_EXEC:
                p->p_flag2 |= P2_STKGAP_DISABLE_EXEC;
                break;
        case 0:
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

static int
stackgap_status(struct thread *td, struct proc *p, void *data)
{
        int d;

        PROC_LOCK_ASSERT(p, MA_OWNED);

        d = (p->p_flag2 & P2_STKGAP_DISABLE) != 0 ? PROC_STACKGAP_DISABLE :
            PROC_STACKGAP_ENABLE;
        d |= (p->p_flag2 & P2_STKGAP_DISABLE_EXEC) != 0 ?
            PROC_STACKGAP_DISABLE_EXEC : PROC_STACKGAP_ENABLE_EXEC;
        *(int *)data = d;
        return (0);
}

static int
wxmap_ctl(struct thread *td, struct proc *p, void *data)
{
        struct vmspace *vm;
        vm_map_t map;
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        if ((p->p_flag & P_WEXIT) != 0)
                return (ESRCH);
        state = *(int *)data;

        switch (state) {
        case PROC_WX_MAPPINGS_PERMIT:
                p->p_flag2 |= P2_WXORX_DISABLE;
                _PHOLD(p);
                PROC_UNLOCK(p);
                vm = vmspace_acquire_ref(p);
                if (vm != NULL) {
                        map = &vm->vm_map;
                        vm_map_lock(map);
                        map->flags &= ~MAP_WXORX;
                        vm_map_unlock(map);
                        vmspace_free(vm);
                }
                PROC_LOCK(p);
                _PRELE(p);
                break;
        case PROC_WX_MAPPINGS_DISALLOW_EXEC:
                p->p_flag2 |= P2_WXORX_ENABLE_EXEC;
                break;
        default:
                return (EINVAL);
        }

        return (0);
}

static int
wxmap_status(struct thread *td, struct proc *p, void *data)
{
        struct vmspace *vm;
        int d;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        if ((p->p_flag & P_WEXIT) != 0)
                return (ESRCH);

        d = 0;
        if ((p->p_flag2 & P2_WXORX_DISABLE) != 0)
                d |= PROC_WX_MAPPINGS_PERMIT;
        if ((p->p_flag2 & P2_WXORX_ENABLE_EXEC) != 0)
                d |= PROC_WX_MAPPINGS_DISALLOW_EXEC;
        _PHOLD(p);
        PROC_UNLOCK(p);
        vm = vmspace_acquire_ref(p);
        if (vm != NULL) {
                if ((vm->vm_map.flags & MAP_WXORX) != 0)
                        d |= PROC_WXORX_ENFORCE;
                vmspace_free(vm);
        }
        PROC_LOCK(p);
        _PRELE(p);
        *(int *)data = d;
        return (0);
}

static int
pdeathsig_ctl(struct thread *td, struct proc *p, void *data)
{
        int signum;

        signum = *(int *)data;
        if (p != td->td_proc || (signum != 0 && !_SIG_VALID(signum)))
                return (EINVAL);
        p->p_pdeathsig = signum;
        return (0);
}

static int
pdeathsig_status(struct thread *td, struct proc *p, void *data)
{
        if (p != td->td_proc)
                return (EINVAL);
        *(int *)data = p->p_pdeathsig;
        return (0);
}

static int
logsigexit_ctl(struct thread *td, struct proc *p, void *data)
{
        int state;

        PROC_LOCK_ASSERT(p, MA_OWNED);
        state = *(int *)data;

        switch (state) {
        case PROC_LOGSIGEXIT_CTL_NOFORCE:
                p->p_flag2 &= ~(P2_LOGSIGEXIT_CTL | P2_LOGSIGEXIT_ENABLE);
                break;
        case PROC_LOGSIGEXIT_CTL_FORCE_ENABLE:
                p->p_flag2 |= P2_LOGSIGEXIT_CTL | P2_LOGSIGEXIT_ENABLE;
                break;
        case PROC_LOGSIGEXIT_CTL_FORCE_DISABLE:
                p->p_flag2 |= P2_LOGSIGEXIT_CTL;
                p->p_flag2 &= ~P2_LOGSIGEXIT_ENABLE;
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

static int
logsigexit_status(struct thread *td, struct proc *p, void *data)
{
        int state;

        if ((p->p_flag2 & P2_LOGSIGEXIT_CTL) == 0)
                state = PROC_LOGSIGEXIT_CTL_NOFORCE;
        else if ((p->p_flag2 & P2_LOGSIGEXIT_ENABLE) != 0)
                state = PROC_LOGSIGEXIT_CTL_FORCE_ENABLE;
        else
                state = PROC_LOGSIGEXIT_CTL_FORCE_DISABLE;
        *(int *)data = state;
        return (0);
}

enum {
        PCTL_SLOCKED,
        PCTL_XLOCKED,
        PCTL_UNLOCKED,
};

struct procctl_cmd_info {
        int lock_tree;
        bool one_proc : 1;
        bool esrch_is_einval : 1;
        bool copyout_on_error : 1;
        bool no_nonnull_data : 1;
        bool need_candebug : 1;
        int copyin_sz;
        int copyout_sz;
        int (*exec)(struct thread *, struct proc *, void *);
        bool (*sapblk)(struct thread *, void *);
};
static const struct procctl_cmd_info procctl_cmds_info[] = {
        [PROC_SPROTECT] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = false,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = protect_set, .copyout_on_error = false, },
        [PROC_REAP_ACQUIRE] =
            { .lock_tree = PCTL_XLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = true,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = 0,
              .exec = reap_acquire, .copyout_on_error = false, },
        [PROC_REAP_RELEASE] =
            { .lock_tree = PCTL_XLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = true,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = 0,
              .exec = reap_release, .copyout_on_error = false, },
        [PROC_REAP_STATUS] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0,
              .copyout_sz = sizeof(struct procctl_reaper_status),
              .exec = reap_status, .copyout_on_error = false, },
        [PROC_REAP_GETPIDS] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = sizeof(struct procctl_reaper_pids),
              .copyout_sz = 0,
              .exec = reap_getpids, .copyout_on_error = false, },
        [PROC_REAP_KILL] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = sizeof(struct procctl_reaper_kill),
              .copyout_sz = sizeof(struct procctl_reaper_kill),
              .exec = reap_kill, .copyout_on_error = true,
              .sapblk = reap_kill_sapblk, },
        [PROC_TRACE_CTL] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = false,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = trace_ctl, .copyout_on_error = false, },
        [PROC_TRACE_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = trace_status, .copyout_on_error = false, },
        [PROC_TRAPCAP_CTL] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = false,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = trapcap_ctl, .copyout_on_error = false, },
        [PROC_TRAPCAP_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = trapcap_status, .copyout_on_error = false, },
        [PROC_PDEATHSIG_CTL] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = true, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = pdeathsig_ctl, .copyout_on_error = false, },
        [PROC_PDEATHSIG_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = true, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = pdeathsig_status, .copyout_on_error = false, },
        [PROC_ASLR_CTL] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = aslr_ctl, .copyout_on_error = false, },
        [PROC_ASLR_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = aslr_status, .copyout_on_error = false, },
        [PROC_PROTMAX_CTL] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = protmax_ctl, .copyout_on_error = false, },
        [PROC_PROTMAX_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = protmax_status, .copyout_on_error = false, },
        [PROC_STACKGAP_CTL] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = stackgap_ctl, .copyout_on_error = false, },
        [PROC_STACKGAP_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = stackgap_status, .copyout_on_error = false, },
        [PROC_NO_NEW_PRIVS_CTL] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = no_new_privs_ctl, .copyout_on_error = false, },
        [PROC_NO_NEW_PRIVS_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = no_new_privs_status, .copyout_on_error = false, },
        [PROC_WXMAP_CTL] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = wxmap_ctl, .copyout_on_error = false, },
        [PROC_WXMAP_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = wxmap_status, .copyout_on_error = false, },
        [PROC_LOGSIGEXIT_CTL] =
            { .lock_tree = PCTL_SLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = true,
              .copyin_sz = sizeof(int), .copyout_sz = 0,
              .exec = logsigexit_ctl, .copyout_on_error = false, },
        [PROC_LOGSIGEXIT_STATUS] =
            { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
              .esrch_is_einval = false, .no_nonnull_data = false,
              .need_candebug = false,
              .copyin_sz = 0, .copyout_sz = sizeof(int),
              .exec = logsigexit_status, .copyout_on_error = false, },
};

int
sys_procctl(struct thread *td, struct procctl_args *uap)
{
        union {
                struct procctl_reaper_status rs;
                struct procctl_reaper_pids rp;
                struct procctl_reaper_kill rk;
                int flags;
        } x;
        const struct procctl_cmd_info *cmd_info;
        int error, error1;

        if (uap->com >= PROC_PROCCTL_MD_MIN)
                return (cpu_procctl(td, uap->idtype, uap->id,
                    uap->com, uap->data));
        if (uap->com <= 0 || uap->com >= nitems(procctl_cmds_info))
                return (EINVAL);
        cmd_info = &procctl_cmds_info[uap->com];
        bzero(&x, sizeof(x));

        if (cmd_info->copyin_sz > 0) {
                error = copyin(uap->data, &x, cmd_info->copyin_sz);
                if (error != 0)
                        return (error);
        } else if (cmd_info->no_nonnull_data && uap->data != NULL) {
                return (EINVAL);
        }

        error = kern_procctl(td, uap->idtype, uap->id, uap->com, &x);

        if (cmd_info->copyout_sz > 0 && (error == 0 ||
            cmd_info->copyout_on_error)) {
                error1 = copyout(&x, uap->data, cmd_info->copyout_sz);
                if (error == 0)
                        error = error1;
        }
        return (error);
}

static int
kern_procctl_single(struct thread *td, struct proc *p, int com, void *data)
{

        PROC_LOCK_ASSERT(p, MA_OWNED);
        return (procctl_cmds_info[com].exec(td, p, data));
}

int
kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data)
{
        struct pgrp *pg;
        struct proc *p;
        const struct procctl_cmd_info *cmd_info;
        int error, first_error, ok;
        bool sapblk;

        MPASS(com > 0 && com < nitems(procctl_cmds_info));
        cmd_info = &procctl_cmds_info[com];
        if (idtype != P_PID && cmd_info->one_proc)
                return (EINVAL);

        sapblk = false;
        if (cmd_info->sapblk != NULL) {
                sapblk = cmd_info->sapblk(td, data);
                if (sapblk && !stop_all_proc_block())
                        return (ERESTART);
        }

        switch (cmd_info->lock_tree) {
        case PCTL_XLOCKED:
                sx_xlock(&proctree_lock);
                break;
        case PCTL_SLOCKED:
                sx_slock(&proctree_lock);
                break;
        default:
                break;
        }

        switch (idtype) {
        case P_PID:
                if (id == 0) {
                        p = td->td_proc;
                        error = 0;
                        PROC_LOCK(p);
                } else {
                        p = pfind(id);
                        if (p == NULL) {
                                error = cmd_info->esrch_is_einval ?
                                    EINVAL : ESRCH;
                                break;
                        }
                        error = cmd_info->need_candebug ? p_candebug(td, p) :
                            p_cansee(td, p);
                }
                if (error == 0)
                        error = kern_procctl_single(td, p, com, data);
                PROC_UNLOCK(p);
                break;
        case P_PGID:
                /*
                 * Attempt to apply the operation to all members of the
                 * group.  Ignore processes in the group that can't be
                 * seen.  Ignore errors so long as at least one process is
                 * able to complete the request successfully.
                 */
                pg = pgfind(id);
                if (pg == NULL) {
                        error = ESRCH;
                        break;
                }
                PGRP_UNLOCK(pg);
                ok = 0;
                first_error = 0;
                LIST_FOREACH(p, &pg->pg_members, p_pglist) {
                        PROC_LOCK(p);
                        if (p->p_state == PRS_NEW ||
                            p->p_state == PRS_ZOMBIE ||
                            (cmd_info->need_candebug ? p_candebug(td, p) :
                            p_cansee(td, p)) != 0) {
                                PROC_UNLOCK(p);
                                continue;
                        }
                        error = kern_procctl_single(td, p, com, data);
                        PROC_UNLOCK(p);
                        if (error == 0)
                                ok = 1;
                        else if (first_error == 0)
                                first_error = error;
                }
                if (ok)
                        error = 0;
                else if (first_error != 0)
                        error = first_error;
                else
                        /*
                         * Was not able to see any processes in the
                         * process group.
                         */
                        error = ESRCH;
                break;
        default:
                error = EINVAL;
                break;
        }

        switch (cmd_info->lock_tree) {
        case PCTL_XLOCKED:
                sx_xunlock(&proctree_lock);
                break;
        case PCTL_SLOCKED:
                sx_sunlock(&proctree_lock);
                break;
        default:
                break;
        }
        if (sapblk)
                stop_all_proc_unblock();
        return (error);
}