The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1989, 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD$");
   39 
   40 #include "opt_compat.h"
   41 #include "opt_kdtrace.h"
   42 #include "opt_ktrace.h"
   43 #include "opt_procdesc.h"
   44 
   45 #include <sys/param.h>
   46 #include <sys/systm.h>
   47 #include <sys/sysproto.h>
   48 #include <sys/capability.h>
   49 #include <sys/eventhandler.h>
   50 #include <sys/kernel.h>
   51 #include <sys/malloc.h>
   52 #include <sys/lock.h>
   53 #include <sys/mutex.h>
   54 #include <sys/proc.h>
   55 #include <sys/procdesc.h>
   56 #include <sys/pioctl.h>
   57 #include <sys/jail.h>
   58 #include <sys/tty.h>
   59 #include <sys/wait.h>
   60 #include <sys/vmmeter.h>
   61 #include <sys/vnode.h>
   62 #include <sys/racct.h>
   63 #include <sys/resourcevar.h>
   64 #include <sys/sbuf.h>
   65 #include <sys/signalvar.h>
   66 #include <sys/sched.h>
   67 #include <sys/sx.h>
   68 #include <sys/syscallsubr.h>
   69 #include <sys/syslog.h>
   70 #include <sys/ptrace.h>
   71 #include <sys/acct.h>           /* for acct_process() function prototype */
   72 #include <sys/filedesc.h>
   73 #include <sys/sdt.h>
   74 #include <sys/shm.h>
   75 #include <sys/sem.h>
   76 #ifdef KTRACE
   77 #include <sys/ktrace.h>
   78 #endif
   79 
   80 #include <security/audit/audit.h>
   81 #include <security/mac/mac_framework.h>
   82 
   83 #include <vm/vm.h>
   84 #include <vm/vm_extern.h>
   85 #include <vm/vm_param.h>
   86 #include <vm/pmap.h>
   87 #include <vm/vm_map.h>
   88 #include <vm/vm_page.h>
   89 #include <vm/uma.h>
   90 
   91 #ifdef KDTRACE_HOOKS
   92 #include <sys/dtrace_bsd.h>
   93 dtrace_execexit_func_t  dtrace_fasttrap_exit;
   94 #endif
   95 
   96 SDT_PROVIDER_DECLARE(proc);
   97 SDT_PROBE_DEFINE1(proc, kernel, , exit, "int");
   98 
   99 /* Hook for NFS teardown procedure. */
  100 void (*nlminfo_release_p)(struct proc *p);
  101 
  102 struct proc *
  103 proc_realparent(struct proc *child)
  104 {
  105         struct proc *p, *parent;
  106 
  107         sx_assert(&proctree_lock, SX_LOCKED);
  108         if ((child->p_treeflag & P_TREE_ORPHANED) == 0) {
  109                 if (child->p_oppid == 0 ||
  110                     child->p_pptr->p_pid == child->p_oppid)
  111                         parent = child->p_pptr;
  112                 else
  113                         parent = initproc;
  114                 return (parent);
  115         }
  116         for (p = child; (p->p_treeflag & P_TREE_FIRST_ORPHAN) == 0;) {
  117                 /* Cannot use LIST_PREV(), since the list head is not known. */
  118                 p = __containerof(p->p_orphan.le_prev, struct proc,
  119                     p_orphan.le_next);
  120                 KASSERT((p->p_treeflag & P_TREE_ORPHANED) != 0,
  121                     ("missing P_ORPHAN %p", p));
  122         }
  123         parent = __containerof(p->p_orphan.le_prev, struct proc,
  124             p_orphans.lh_first);
  125         return (parent);
  126 }
  127 
  128 static void
  129 clear_orphan(struct proc *p)
  130 {
  131         struct proc *p1;
  132 
  133         sx_assert(&proctree_lock, SA_XLOCKED);
  134         if ((p->p_treeflag & P_TREE_ORPHANED) == 0)
  135                 return;
  136         if ((p->p_treeflag & P_TREE_FIRST_ORPHAN) != 0) {
  137                 p1 = LIST_NEXT(p, p_orphan);
  138                 if (p1 != NULL)
  139                         p1->p_treeflag |= P_TREE_FIRST_ORPHAN;
  140                 p->p_treeflag &= ~P_TREE_FIRST_ORPHAN;
  141         }
  142         LIST_REMOVE(p, p_orphan);
  143         p->p_treeflag &= ~P_TREE_ORPHANED;
  144 }
  145 
  146 /*
  147  * exit -- death of process.
  148  */
  149 void
  150 sys_sys_exit(struct thread *td, struct sys_exit_args *uap)
  151 {
  152 
  153         exit1(td, W_EXITCODE(uap->rval, 0));
  154         /* NOTREACHED */
  155 }
  156 
  157 /*
  158  * Exit: deallocate address space and other resources, change proc state to
  159  * zombie, and unlink proc from allproc and parent's lists.  Save exit status
  160  * and rusage for wait().  Check for child processes and orphan them.
  161  */
  162 void
  163 exit1(struct thread *td, int rv)
  164 {
  165         struct proc *p, *nq, *q, *t;
  166         struct thread *tdt;
  167         struct vnode *vtmp;
  168         struct vnode *ttyvp = NULL;
  169         struct plimit *plim;
  170         int locked;
  171 
  172         mtx_assert(&Giant, MA_NOTOWNED);
  173 
  174         p = td->td_proc;
  175         /*
  176          * XXX in case we're rebooting we just let init die in order to
  177          * work around an unsolved stack overflow seen very late during
  178          * shutdown on sparc64 when the gmirror worker process exists.
  179          */
  180         if (p == initproc && rebooting == 0) {
  181                 printf("init died (signal %d, exit %d)\n",
  182                     WTERMSIG(rv), WEXITSTATUS(rv));
  183                 panic("Going nowhere without my init!");
  184         }
  185 
  186         /*
  187          * MUST abort all other threads before proceeding past here.
  188          */
  189         PROC_LOCK(p);
  190         while (p->p_flag & P_HADTHREADS) {
  191                 /*
  192                  * First check if some other thread got here before us..
  193                  * if so, act apropriatly, (exit or suspend);
  194                  */
  195                 thread_suspend_check(0);
  196 
  197                 /*
  198                  * Kill off the other threads. This requires
  199                  * some co-operation from other parts of the kernel
  200                  * so it may not be instantaneous.  With this state set
  201                  * any thread entering the kernel from userspace will
  202                  * thread_exit() in trap().  Any thread attempting to
  203                  * sleep will return immediately with EINTR or EWOULDBLOCK
  204                  * which will hopefully force them to back out to userland
  205                  * freeing resources as they go.  Any thread attempting
  206                  * to return to userland will thread_exit() from userret().
  207                  * thread_exit() will unsuspend us when the last of the
  208                  * other threads exits.
  209                  * If there is already a thread singler after resumption,
  210                  * calling thread_single will fail; in that case, we just
  211                  * re-check all suspension request, the thread should
  212                  * either be suspended there or exit.
  213                  */
  214                 if (! thread_single(SINGLE_EXIT))
  215                         break;
  216 
  217                 /*
  218                  * All other activity in this process is now stopped.
  219                  * Threading support has been turned off.
  220                  */
  221         }
  222         KASSERT(p->p_numthreads == 1,
  223             ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
  224         racct_sub(p, RACCT_NTHR, 1);
  225         /*
  226          * Wakeup anyone in procfs' PIOCWAIT.  They should have a hold
  227          * on our vmspace, so we should block below until they have
  228          * released their reference to us.  Note that if they have
  229          * requested S_EXIT stops we will block here until they ack
  230          * via PIOCCONT.
  231          */
  232         _STOPEVENT(p, S_EXIT, rv);
  233 
  234         /*
  235          * Ignore any pending request to stop due to a stop signal.
  236          * Once P_WEXIT is set, future requests will be ignored as
  237          * well.
  238          */
  239         p->p_flag &= ~P_STOPPED_SIG;
  240         KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped"));
  241 
  242         /*
  243          * Note that we are exiting and do another wakeup of anyone in
  244          * PIOCWAIT in case they aren't listening for S_EXIT stops or
  245          * decided to wait again after we told them we are exiting.
  246          */
  247         p->p_flag |= P_WEXIT;
  248         wakeup(&p->p_stype);
  249 
  250         /*
  251          * Wait for any processes that have a hold on our vmspace to
  252          * release their reference.
  253          */
  254         while (p->p_lock > 0)
  255                 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
  256 
  257         p->p_xstat = rv;        /* Let event handler change exit status */
  258         PROC_UNLOCK(p);
  259         /* Drain the limit callout while we don't have the proc locked */
  260         callout_drain(&p->p_limco);
  261 
  262 #ifdef AUDIT
  263         /*
  264          * The Sun BSM exit token contains two components: an exit status as
  265          * passed to exit(), and a return value to indicate what sort of exit
  266          * it was.  The exit status is WEXITSTATUS(rv), but it's not clear
  267          * what the return value is.
  268          */
  269         AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0);
  270         AUDIT_SYSCALL_EXIT(0, td);
  271 #endif
  272 
  273         /* Are we a task leader? */
  274         if (p == p->p_leader) {
  275                 mtx_lock(&ppeers_lock);
  276                 q = p->p_peers;
  277                 while (q != NULL) {
  278                         PROC_LOCK(q);
  279                         kern_psignal(q, SIGKILL);
  280                         PROC_UNLOCK(q);
  281                         q = q->p_peers;
  282                 }
  283                 while (p->p_peers != NULL)
  284                         msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
  285                 mtx_unlock(&ppeers_lock);
  286         }
  287 
  288         /*
  289          * Check if any loadable modules need anything done at process exit.
  290          * E.g. SYSV IPC stuff
  291          * XXX what if one of these generates an error?
  292          */
  293         EVENTHANDLER_INVOKE(process_exit, p);
  294 
  295         /*
  296          * If parent is waiting for us to exit or exec,
  297          * P_PPWAIT is set; we will wakeup the parent below.
  298          */
  299         PROC_LOCK(p);
  300         rv = p->p_xstat;        /* Event handler could change exit status */
  301         stopprofclock(p);
  302         p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE);
  303 
  304         /*
  305          * Stop the real interval timer.  If the handler is currently
  306          * executing, prevent it from rearming itself and let it finish.
  307          */
  308         if (timevalisset(&p->p_realtimer.it_value) &&
  309             callout_stop(&p->p_itcallout) == 0) {
  310                 timevalclear(&p->p_realtimer.it_interval);
  311                 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
  312                 KASSERT(!timevalisset(&p->p_realtimer.it_value),
  313                     ("realtime timer is still armed"));
  314         }
  315         PROC_UNLOCK(p);
  316 
  317         /*
  318          * Reset any sigio structures pointing to us as a result of
  319          * F_SETOWN with our pid.
  320          */
  321         funsetownlst(&p->p_sigiolst);
  322 
  323         /*
  324          * If this process has an nlminfo data area (for lockd), release it
  325          */
  326         if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
  327                 (*nlminfo_release_p)(p);
  328 
  329         /*
  330          * Close open files and release open-file table.
  331          * This may block!
  332          */
  333         fdfree(td);
  334 
  335         /*
  336          * If this thread tickled GEOM, we need to wait for the giggling to
  337          * stop before we return to userland
  338          */
  339         if (td->td_pflags & TDP_GEOM)
  340                 g_waitidle();
  341 
  342         /*
  343          * Remove ourself from our leader's peer list and wake our leader.
  344          */
  345         mtx_lock(&ppeers_lock);
  346         if (p->p_leader->p_peers) {
  347                 q = p->p_leader;
  348                 while (q->p_peers != p)
  349                         q = q->p_peers;
  350                 q->p_peers = p->p_peers;
  351                 wakeup(p->p_leader);
  352         }
  353         mtx_unlock(&ppeers_lock);
  354 
  355         vmspace_exit(td);
  356 
  357         sx_xlock(&proctree_lock);
  358         if (SESS_LEADER(p)) {
  359                 struct session *sp = p->p_session;
  360                 struct tty *tp;
  361 
  362                 /*
  363                  * s_ttyp is not zero'd; we use this to indicate that
  364                  * the session once had a controlling terminal. (for
  365                  * logging and informational purposes)
  366                  */
  367                 SESS_LOCK(sp);
  368                 ttyvp = sp->s_ttyvp;
  369                 tp = sp->s_ttyp;
  370                 sp->s_ttyvp = NULL;
  371                 sp->s_ttydp = NULL;
  372                 sp->s_leader = NULL;
  373                 SESS_UNLOCK(sp);
  374 
  375                 /*
  376                  * Signal foreground pgrp and revoke access to
  377                  * controlling terminal if it has not been revoked
  378                  * already.
  379                  *
  380                  * Because the TTY may have been revoked in the mean
  381                  * time and could already have a new session associated
  382                  * with it, make sure we don't send a SIGHUP to a
  383                  * foreground process group that does not belong to this
  384                  * session.
  385                  */
  386 
  387                 if (tp != NULL) {
  388                         tty_lock(tp);
  389                         if (tp->t_session == sp)
  390                                 tty_signal_pgrp(tp, SIGHUP);
  391                         tty_unlock(tp);
  392                 }
  393 
  394                 if (ttyvp != NULL) {
  395                         sx_xunlock(&proctree_lock);
  396                         if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) {
  397                                 VOP_REVOKE(ttyvp, REVOKEALL);
  398                                 VOP_UNLOCK(ttyvp, 0);
  399                         }
  400                         sx_xlock(&proctree_lock);
  401                 }
  402         }
  403         fixjobc(p, p->p_pgrp, 0);
  404         sx_xunlock(&proctree_lock);
  405         (void)acct_process(td);
  406 
  407         /* Release the TTY now we've unlocked everything. */
  408         if (ttyvp != NULL)
  409                 vrele(ttyvp);
  410 #ifdef KTRACE
  411         ktrprocexit(td);
  412 #endif
  413         /*
  414          * Release reference to text vnode
  415          */
  416         if ((vtmp = p->p_textvp) != NULL) {
  417                 p->p_textvp = NULL;
  418                 locked = VFS_LOCK_GIANT(vtmp->v_mount);
  419                 vrele(vtmp);
  420                 VFS_UNLOCK_GIANT(locked);
  421         }
  422 
  423         /*
  424          * Release our limits structure.
  425          */
  426         PROC_LOCK(p);
  427         plim = p->p_limit;
  428         p->p_limit = NULL;
  429         PROC_UNLOCK(p);
  430         lim_free(plim);
  431 
  432         tidhash_remove(td);
  433 
  434         /*
  435          * Remove proc from allproc queue and pidhash chain.
  436          * Place onto zombproc.  Unlink from parent's child list.
  437          */
  438         sx_xlock(&allproc_lock);
  439         LIST_REMOVE(p, p_list);
  440         LIST_INSERT_HEAD(&zombproc, p, p_list);
  441         LIST_REMOVE(p, p_hash);
  442         sx_xunlock(&allproc_lock);
  443 
  444         /*
  445          * Call machine-dependent code to release any
  446          * machine-dependent resources other than the address space.
  447          * The address space is released by "vmspace_exitfree(p)" in
  448          * vm_waitproc().
  449          */
  450         cpu_exit(td);
  451 
  452         WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
  453 
  454         /*
  455          * Reparent all children processes:
  456          * - traced ones to the original parent (or init if we are that parent)
  457          * - the rest to init
  458          */
  459         sx_xlock(&proctree_lock);
  460         q = LIST_FIRST(&p->p_children);
  461         if (q != NULL)          /* only need this if any child is S_ZOMB */
  462                 wakeup(initproc);
  463         for (; q != NULL; q = nq) {
  464                 nq = LIST_NEXT(q, p_sibling);
  465                 PROC_LOCK(q);
  466                 q->p_sigparent = SIGCHLD;
  467 
  468                 if (!(q->p_flag & P_TRACED)) {
  469                         proc_reparent(q, initproc);
  470                 } else {
  471                         /*
  472                          * Traced processes are killed since their existence
  473                          * means someone is screwing up.
  474                          */
  475                         t = proc_realparent(q);
  476                         if (t == p) {
  477                                 proc_reparent(q, initproc);
  478                         } else {
  479                                 PROC_LOCK(t);
  480                                 proc_reparent(q, t);
  481                                 PROC_UNLOCK(t);
  482                         }
  483                         /*
  484                          * Since q was found on our children list, the
  485                          * proc_reparent() call moved q to the orphan
  486                          * list due to present P_TRACED flag. Clear
  487                          * orphan link for q now while q is locked.
  488                          */
  489                         clear_orphan(q);
  490                         q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
  491                         FOREACH_THREAD_IN_PROC(q, tdt)
  492                                 tdt->td_dbgflags &= ~TDB_SUSPEND;
  493                         kern_psignal(q, SIGKILL);
  494                 }
  495                 PROC_UNLOCK(q);
  496         }
  497 
  498         /*
  499          * Also get rid of our orphans.
  500          */
  501         while ((q = LIST_FIRST(&p->p_orphans)) != NULL) {
  502                 PROC_LOCK(q);
  503                 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid,
  504                     q->p_pid);
  505                 clear_orphan(q);
  506                 PROC_UNLOCK(q);
  507         }
  508 
  509         /* Save exit status. */
  510         PROC_LOCK(p);
  511         p->p_xthread = td;
  512 
  513         /* Tell the prison that we are gone. */
  514         prison_proc_free(p->p_ucred->cr_prison);
  515 
  516 #ifdef KDTRACE_HOOKS
  517         /*
  518          * Tell the DTrace fasttrap provider about the exit if it
  519          * has declared an interest.
  520          */
  521         if (dtrace_fasttrap_exit)
  522                 dtrace_fasttrap_exit(p);
  523 #endif
  524 
  525         /*
  526          * Notify interested parties of our demise.
  527          */
  528         KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
  529 
  530 #ifdef KDTRACE_HOOKS
  531         int reason = CLD_EXITED;
  532         if (WCOREDUMP(rv))
  533                 reason = CLD_DUMPED;
  534         else if (WIFSIGNALED(rv))
  535                 reason = CLD_KILLED;
  536         SDT_PROBE1(proc, kernel, , exit, reason);
  537 #endif
  538 
  539         /*
  540          * Just delete all entries in the p_klist. At this point we won't
  541          * report any more events, and there are nasty race conditions that
  542          * can beat us if we don't.
  543          */
  544         knlist_clear(&p->p_klist, 1);
  545 
  546         /*
  547          * If this is a process with a descriptor, we may not need to deliver
  548          * a signal to the parent.  proctree_lock is held over
  549          * procdesc_exit() to serialize concurrent calls to close() and
  550          * exit().
  551          */
  552 #ifdef PROCDESC
  553         if (p->p_procdesc == NULL || procdesc_exit(p)) {
  554 #endif
  555                 /*
  556                  * Notify parent that we're gone.  If parent has the
  557                  * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN,
  558                  * notify process 1 instead (and hope it will handle this
  559                  * situation).
  560                  */
  561                 PROC_LOCK(p->p_pptr);
  562                 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
  563                 if (p->p_pptr->p_sigacts->ps_flag &
  564                     (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
  565                         struct proc *pp;
  566 
  567                         mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
  568                         pp = p->p_pptr;
  569                         PROC_UNLOCK(pp);
  570                         proc_reparent(p, initproc);
  571                         p->p_sigparent = SIGCHLD;
  572                         PROC_LOCK(p->p_pptr);
  573 
  574                         /*
  575                          * Notify parent, so in case he was wait(2)ing or
  576                          * executing waitpid(2) with our pid, he will
  577                          * continue.
  578                          */
  579                         wakeup(pp);
  580                 } else
  581                         mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
  582 
  583                 if (p->p_pptr == initproc)
  584                         kern_psignal(p->p_pptr, SIGCHLD);
  585                 else if (p->p_sigparent != 0) {
  586                         if (p->p_sigparent == SIGCHLD)
  587                                 childproc_exited(p);
  588                         else    /* LINUX thread */
  589                                 kern_psignal(p->p_pptr, p->p_sigparent);
  590                 }
  591 #ifdef PROCDESC
  592         } else
  593                 PROC_LOCK(p->p_pptr);
  594 #endif
  595         sx_xunlock(&proctree_lock);
  596 
  597         /*
  598          * The state PRS_ZOMBIE prevents other proesses from sending
  599          * signal to the process, to avoid memory leak, we free memory
  600          * for signal queue at the time when the state is set.
  601          */
  602         sigqueue_flush(&p->p_sigqueue);
  603         sigqueue_flush(&td->td_sigqueue);
  604 
  605         /*
  606          * We have to wait until after acquiring all locks before
  607          * changing p_state.  We need to avoid all possible context
  608          * switches (including ones from blocking on a mutex) while
  609          * marked as a zombie.  We also have to set the zombie state
  610          * before we release the parent process' proc lock to avoid
  611          * a lost wakeup.  So, we first call wakeup, then we grab the
  612          * sched lock, update the state, and release the parent process'
  613          * proc lock.
  614          */
  615         wakeup(p->p_pptr);
  616         cv_broadcast(&p->p_pwait);
  617         sched_exit(p->p_pptr, td);
  618         PROC_SLOCK(p);
  619         p->p_state = PRS_ZOMBIE;
  620         PROC_UNLOCK(p->p_pptr);
  621 
  622         /*
  623          * Hopefully no one will try to deliver a signal to the process this
  624          * late in the game.
  625          */
  626         knlist_destroy(&p->p_klist);
  627 
  628         /*
  629          * Save our children's rusage information in our exit rusage.
  630          */
  631         ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
  632 
  633         /*
  634          * Make sure the scheduler takes this thread out of its tables etc.
  635          * This will also release this thread's reference to the ucred.
  636          * Other thread parts to release include pcb bits and such.
  637          */
  638         thread_exit();
  639 }
  640 
  641 
  642 #ifndef _SYS_SYSPROTO_H_
  643 struct abort2_args {
  644         char *why;
  645         int nargs;
  646         void **args;
  647 };
  648 #endif
  649 
  650 int
  651 sys_abort2(struct thread *td, struct abort2_args *uap)
  652 {
  653         struct proc *p = td->td_proc;
  654         struct sbuf *sb;
  655         void *uargs[16];
  656         int error, i, sig;
  657 
  658         /*
  659          * Do it right now so we can log either proper call of abort2(), or
  660          * note, that invalid argument was passed. 512 is big enough to
  661          * handle 16 arguments' descriptions with additional comments.
  662          */
  663         sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
  664         sbuf_clear(sb);
  665         sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
  666             p->p_comm, p->p_pid, td->td_ucred->cr_uid);
  667         /*
  668          * Since we can't return from abort2(), send SIGKILL in cases, where
  669          * abort2() was called improperly
  670          */
  671         sig = SIGKILL;
  672         /* Prevent from DoSes from user-space. */
  673         if (uap->nargs < 0 || uap->nargs > 16)
  674                 goto out;
  675         if (uap->nargs > 0) {
  676                 if (uap->args == NULL)
  677                         goto out;
  678                 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
  679                 if (error != 0)
  680                         goto out;
  681         }
  682         /*
  683          * Limit size of 'reason' string to 128. Will fit even when
  684          * maximal number of arguments was chosen to be logged.
  685          */
  686         if (uap->why != NULL) {
  687                 error = sbuf_copyin(sb, uap->why, 128);
  688                 if (error < 0)
  689                         goto out;
  690         } else {
  691                 sbuf_printf(sb, "(null)");
  692         }
  693         if (uap->nargs > 0) {
  694                 sbuf_printf(sb, "(");
  695                 for (i = 0;i < uap->nargs; i++)
  696                         sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
  697                 sbuf_printf(sb, ")");
  698         }
  699         /*
  700          * Final stage: arguments were proper, string has been
  701          * successfully copied from userspace, and copying pointers
  702          * from user-space succeed.
  703          */
  704         sig = SIGABRT;
  705 out:
  706         if (sig == SIGKILL) {
  707                 sbuf_trim(sb);
  708                 sbuf_printf(sb, " (Reason text inaccessible)");
  709         }
  710         sbuf_cat(sb, "\n");
  711         sbuf_finish(sb);
  712         log(LOG_INFO, "%s", sbuf_data(sb));
  713         sbuf_delete(sb);
  714         exit1(td, W_EXITCODE(0, sig));
  715         return (0);
  716 }
  717 
  718 
  719 #ifdef COMPAT_43
  720 /*
  721  * The dirty work is handled by kern_wait().
  722  */
  723 int
  724 owait(struct thread *td, struct owait_args *uap __unused)
  725 {
  726         int error, status;
  727 
  728         error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
  729         if (error == 0)
  730                 td->td_retval[1] = status;
  731         return (error);
  732 }
  733 #endif /* COMPAT_43 */
  734 
  735 /*
  736  * The dirty work is handled by kern_wait().
  737  */
  738 int
  739 sys_wait4(struct thread *td, struct wait4_args *uap)
  740 {
  741         struct rusage ru, *rup;
  742         int error, status;
  743 
  744         if (uap->rusage != NULL)
  745                 rup = &ru;
  746         else
  747                 rup = NULL;
  748         error = kern_wait(td, uap->pid, &status, uap->options, rup);
  749         if (uap->status != NULL && error == 0)
  750                 error = copyout(&status, uap->status, sizeof(status));
  751         if (uap->rusage != NULL && error == 0)
  752                 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
  753         return (error);
  754 }
  755 
  756 int
  757 sys_wait6(struct thread *td, struct wait6_args *uap)
  758 {
  759         struct __wrusage wru, *wrup;
  760         siginfo_t si, *sip;
  761         idtype_t idtype;
  762         id_t id;
  763         int error, status;
  764 
  765         idtype = uap->idtype;
  766         id = uap->id;
  767 
  768         if (uap->wrusage != NULL)
  769                 wrup = &wru;
  770         else
  771                 wrup = NULL;
  772 
  773         if (uap->info != NULL) {
  774                 sip = &si;
  775                 bzero(sip, sizeof(*sip));
  776         } else
  777                 sip = NULL;
  778 
  779         /*
  780          *  We expect all callers of wait6() to know about WEXITED and
  781          *  WTRAPPED.
  782          */
  783         error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip);
  784 
  785         if (uap->status != NULL && error == 0)
  786                 error = copyout(&status, uap->status, sizeof(status));
  787         if (uap->wrusage != NULL && error == 0)
  788                 error = copyout(&wru, uap->wrusage, sizeof(wru));
  789         if (uap->info != NULL && error == 0)
  790                 error = copyout(&si, uap->info, sizeof(si));
  791         return (error);
  792 }
  793 
  794 /*
  795  * Reap the remains of a zombie process and optionally return status and
  796  * rusage.  Asserts and will release both the proctree_lock and the process
  797  * lock as part of its work.
  798  */
  799 void
  800 proc_reap(struct thread *td, struct proc *p, int *status, int options)
  801 {
  802         struct proc *q, *t;
  803 
  804         sx_assert(&proctree_lock, SA_XLOCKED);
  805         PROC_LOCK_ASSERT(p, MA_OWNED);
  806         PROC_SLOCK_ASSERT(p, MA_OWNED);
  807         KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
  808 
  809         q = td->td_proc;
  810 
  811         PROC_SUNLOCK(p);
  812         td->td_retval[0] = p->p_pid;
  813         if (status)
  814                 *status = p->p_xstat;   /* convert to int */
  815         if (options & WNOWAIT) {
  816                 /*
  817                  *  Only poll, returning the status.  Caller does not wish to
  818                  * release the proc struct just yet.
  819                  */
  820                 PROC_UNLOCK(p);
  821                 sx_xunlock(&proctree_lock);
  822                 return;
  823         }
  824 
  825         PROC_LOCK(q);
  826         sigqueue_take(p->p_ksi);
  827         PROC_UNLOCK(q);
  828 
  829         /*
  830          * If we got the child via a ptrace 'attach', we need to give it back
  831          * to the old parent.
  832          */
  833         if (p->p_oppid != 0 && p->p_oppid != p->p_pptr->p_pid) {
  834                 PROC_UNLOCK(p);
  835                 t = proc_realparent(p);
  836                 PROC_LOCK(t);
  837                 PROC_LOCK(p);
  838                 CTR2(KTR_PTRACE,
  839                     "wait: traced child %d moved back to parent %d", p->p_pid,
  840                     t->p_pid);
  841                 proc_reparent(p, t);
  842                 p->p_oppid = 0;
  843                 PROC_UNLOCK(p);
  844                 pksignal(t, SIGCHLD, p->p_ksi);
  845                 wakeup(t);
  846                 cv_broadcast(&p->p_pwait);
  847                 PROC_UNLOCK(t);
  848                 sx_xunlock(&proctree_lock);
  849                 return;
  850         }
  851         p->p_oppid = 0;
  852         PROC_UNLOCK(p);
  853 
  854         /*
  855          * Remove other references to this process to ensure we have an
  856          * exclusive reference.
  857          */
  858         sx_xlock(&allproc_lock);
  859         LIST_REMOVE(p, p_list); /* off zombproc */
  860         sx_xunlock(&allproc_lock);
  861         LIST_REMOVE(p, p_sibling);
  862         PROC_LOCK(p);
  863         clear_orphan(p);
  864         PROC_UNLOCK(p);
  865         leavepgrp(p);
  866 #ifdef PROCDESC
  867         if (p->p_procdesc != NULL)
  868                 procdesc_reap(p);
  869 #endif
  870         sx_xunlock(&proctree_lock);
  871 
  872         /*
  873          * As a side effect of this lock, we know that all other writes to
  874          * this proc are visible now, so no more locking is needed for p.
  875          */
  876         PROC_LOCK(p);
  877         p->p_xstat = 0;         /* XXX: why? */
  878         PROC_UNLOCK(p);
  879         PROC_LOCK(q);
  880         ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
  881         PROC_UNLOCK(q);
  882 
  883         /*
  884          * Decrement the count of procs running with this uid.
  885          */
  886         (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
  887 
  888         /*
  889          * Destroy resource accounting information associated with the process.
  890          */
  891 #ifdef RACCT
  892         PROC_LOCK(p);
  893         racct_sub(p, RACCT_NPROC, 1);
  894         PROC_UNLOCK(p);
  895 #endif
  896         racct_proc_exit(p);
  897 
  898         /*
  899          * Free credentials, arguments, and sigacts.
  900          */
  901         crfree(p->p_ucred);
  902         p->p_ucred = NULL;
  903         pargs_drop(p->p_args);
  904         p->p_args = NULL;
  905         sigacts_free(p->p_sigacts);
  906         p->p_sigacts = NULL;
  907 
  908         /*
  909          * Do any thread-system specific cleanups.
  910          */
  911         thread_wait(p);
  912 
  913         /*
  914          * Give vm and machine-dependent layer a chance to free anything that
  915          * cpu_exit couldn't release while still running in process context.
  916          */
  917         vm_waitproc(p);
  918 #ifdef MAC
  919         mac_proc_destroy(p);
  920 #endif
  921         KASSERT(FIRST_THREAD_IN_PROC(p),
  922             ("proc_reap: no residual thread!"));
  923         uma_zfree(proc_zone, p);
  924         sx_xlock(&allproc_lock);
  925         nprocs--;
  926         sx_xunlock(&allproc_lock);
  927 }
  928 
  929 static int
  930 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
  931     int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo,
  932     int check_only)
  933 {
  934         struct proc *q;
  935         struct rusage *rup;
  936 
  937         sx_assert(&proctree_lock, SA_XLOCKED);
  938 
  939         q = td->td_proc;
  940         PROC_LOCK(p);
  941 
  942         switch (idtype) {
  943         case P_ALL:
  944                 break;
  945         case P_PID:
  946                 if (p->p_pid != (pid_t)id) {
  947                         PROC_UNLOCK(p);
  948                         return (0);
  949                 }
  950                 break;
  951         case P_PGID:
  952                 if (p->p_pgid != (pid_t)id) {
  953                         PROC_UNLOCK(p);
  954                         return (0);
  955                 }
  956                 break;
  957         case P_SID:
  958                 if (p->p_session->s_sid != (pid_t)id) {
  959                         PROC_UNLOCK(p);
  960                         return (0);
  961                 }
  962                 break;
  963         case P_UID:
  964                 if (p->p_ucred->cr_uid != (uid_t)id) {
  965                         PROC_UNLOCK(p);
  966                         return (0);
  967                 }
  968                 break;
  969         case P_GID:
  970                 if (p->p_ucred->cr_gid != (gid_t)id) {
  971                         PROC_UNLOCK(p);
  972                         return (0);
  973                 }
  974                 break;
  975         case P_JAILID:
  976                 if (p->p_ucred->cr_prison == NULL ||
  977                     (p->p_ucred->cr_prison->pr_id != (int)id)) {
  978                         PROC_UNLOCK(p);
  979                         return (0);
  980                 }
  981                 break;
  982         /*
  983          * It seems that the thread structures get zeroed out
  984          * at process exit.  This makes it impossible to
  985          * support P_SETID, P_CID or P_CPUID.
  986          */
  987         default:
  988                 PROC_UNLOCK(p);
  989                 return (0);
  990         }
  991 
  992         if (p_canwait(td, p)) {
  993                 PROC_UNLOCK(p);
  994                 return (0);
  995         }
  996 
  997         if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) {
  998                 PROC_UNLOCK(p);
  999                 return (0);
 1000         }
 1001 
 1002         /*
 1003          * This special case handles a kthread spawned by linux_clone
 1004          * (see linux_misc.c).  The linux_wait4 and linux_waitpid
 1005          * functions need to be able to distinguish between waiting
 1006          * on a process and waiting on a thread.  It is a thread if
 1007          * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
 1008          * signifies we want to wait for threads and not processes.
 1009          */
 1010         if ((p->p_sigparent != SIGCHLD) ^
 1011             ((options & WLINUXCLONE) != 0)) {
 1012                 PROC_UNLOCK(p);
 1013                 return (0);
 1014         }
 1015 
 1016         PROC_SLOCK(p);
 1017 
 1018         if (siginfo != NULL) {
 1019                 bzero(siginfo, sizeof(*siginfo));
 1020                 siginfo->si_errno = 0;
 1021 
 1022                 /*
 1023                  * SUSv4 requires that the si_signo value is always
 1024                  * SIGCHLD. Obey it despite the rfork(2) interface
 1025                  * allows to request other signal for child exit
 1026                  * notification.
 1027                  */
 1028                 siginfo->si_signo = SIGCHLD;
 1029 
 1030                 /*
 1031                  *  This is still a rough estimate.  We will fix the
 1032                  *  cases TRAPPED, STOPPED, and CONTINUED later.
 1033                  */
 1034                 if (WCOREDUMP(p->p_xstat)) {
 1035                         siginfo->si_code = CLD_DUMPED;
 1036                         siginfo->si_status = WTERMSIG(p->p_xstat);
 1037                 } else if (WIFSIGNALED(p->p_xstat)) {
 1038                         siginfo->si_code = CLD_KILLED;
 1039                         siginfo->si_status = WTERMSIG(p->p_xstat);
 1040                 } else {
 1041                         siginfo->si_code = CLD_EXITED;
 1042                         siginfo->si_status = WEXITSTATUS(p->p_xstat);
 1043                 }
 1044 
 1045                 siginfo->si_pid = p->p_pid;
 1046                 siginfo->si_uid = p->p_ucred->cr_uid;
 1047 
 1048                 /*
 1049                  * The si_addr field would be useful additional
 1050                  * detail, but apparently the PC value may be lost
 1051                  * when we reach this point.  bzero() above sets
 1052                  * siginfo->si_addr to NULL.
 1053                  */
 1054         }
 1055 
 1056         /*
 1057          * There should be no reason to limit resources usage info to
 1058          * exited processes only.  A snapshot about any resources used
 1059          * by a stopped process may be exactly what is needed.
 1060          */
 1061         if (wrusage != NULL) {
 1062                 rup = &wrusage->wru_self;
 1063                 *rup = p->p_ru;
 1064                 calcru(p, &rup->ru_utime, &rup->ru_stime);
 1065 
 1066                 rup = &wrusage->wru_children;
 1067                 *rup = p->p_stats->p_cru;
 1068                 calccru(p, &rup->ru_utime, &rup->ru_stime);
 1069         }
 1070 
 1071         if (p->p_state == PRS_ZOMBIE && !check_only) {
 1072                 proc_reap(td, p, status, options);
 1073                 return (-1);
 1074         }
 1075         PROC_SUNLOCK(p);
 1076         PROC_UNLOCK(p);
 1077         return (1);
 1078 }
 1079 
 1080 int
 1081 kern_wait(struct thread *td, pid_t pid, int *status, int options,
 1082     struct rusage *rusage)
 1083 {
 1084         struct __wrusage wru, *wrup;
 1085         idtype_t idtype;
 1086         id_t id;
 1087         int ret;
 1088 
 1089         /*
 1090          * Translate the special pid values into the (idtype, pid)
 1091          * pair for kern_wait6.  The WAIT_MYPGRP case is handled by
 1092          * kern_wait6() on its own.
 1093          */
 1094         if (pid == WAIT_ANY) {
 1095                 idtype = P_ALL;
 1096                 id = 0;
 1097         } else if (pid < 0) {
 1098                 idtype = P_PGID;
 1099                 id = (id_t)-pid;
 1100         } else {
 1101                 idtype = P_PID;
 1102                 id = (id_t)pid;
 1103         }
 1104 
 1105         if (rusage != NULL)
 1106                 wrup = &wru;
 1107         else
 1108                 wrup = NULL;
 1109 
 1110         /*
 1111          * For backward compatibility we implicitly add flags WEXITED
 1112          * and WTRAPPED here.
 1113          */
 1114         options |= WEXITED | WTRAPPED;
 1115         ret = kern_wait6(td, idtype, id, status, options, wrup, NULL);
 1116         if (rusage != NULL)
 1117                 *rusage = wru.wru_self;
 1118         return (ret);
 1119 }
 1120 
 1121 int
 1122 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status,
 1123     int options, struct __wrusage *wrusage, siginfo_t *siginfo)
 1124 {
 1125         struct proc *p, *q;
 1126         int error, nfound, ret;
 1127 
 1128         AUDIT_ARG_VALUE((int)idtype);   /* XXX - This is likely wrong! */
 1129         AUDIT_ARG_PID((pid_t)id);       /* XXX - This may be wrong! */
 1130         AUDIT_ARG_VALUE(options);
 1131 
 1132         q = td->td_proc;
 1133 
 1134         if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) {
 1135                 PROC_LOCK(q);
 1136                 id = (id_t)q->p_pgid;
 1137                 PROC_UNLOCK(q);
 1138                 idtype = P_PGID;
 1139         }
 1140 
 1141         /* If we don't know the option, just return. */
 1142         if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT |
 1143             WEXITED | WTRAPPED | WLINUXCLONE)) != 0)
 1144                 return (EINVAL);
 1145         if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) {
 1146                 /*
 1147                  * We will be unable to find any matching processes,
 1148                  * because there are no known events to look for.
 1149                  * Prefer to return error instead of blocking
 1150                  * indefinitely.
 1151                  */
 1152                 return (EINVAL);
 1153         }
 1154 
 1155 loop:
 1156         if (q->p_flag & P_STATCHILD) {
 1157                 PROC_LOCK(q);
 1158                 q->p_flag &= ~P_STATCHILD;
 1159                 PROC_UNLOCK(q);
 1160         }
 1161         nfound = 0;
 1162         sx_xlock(&proctree_lock);
 1163         LIST_FOREACH(p, &q->p_children, p_sibling) {
 1164                 ret = proc_to_reap(td, p, idtype, id, status, options,
 1165                     wrusage, siginfo, 0);
 1166                 if (ret == 0)
 1167                         continue;
 1168                 else if (ret == 1)
 1169                         nfound++;
 1170                 else
 1171                         return (0);
 1172 
 1173                 PROC_LOCK(p);
 1174                 PROC_SLOCK(p);
 1175 
 1176                 if ((options & WTRAPPED) != 0 &&
 1177                     (p->p_flag & P_TRACED) != 0 &&
 1178                     (p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) != 0 &&
 1179                     (p->p_suspcount == p->p_numthreads) &&
 1180                     ((p->p_flag & P_WAITED) == 0)) {
 1181                         PROC_SUNLOCK(p);
 1182                         if ((options & WNOWAIT) == 0)
 1183                                 p->p_flag |= P_WAITED;
 1184                         sx_xunlock(&proctree_lock);
 1185                         td->td_retval[0] = p->p_pid;
 1186 
 1187                         if (status != NULL)
 1188                                 *status = W_STOPCODE(p->p_xstat);
 1189                         if (siginfo != NULL) {
 1190                                 siginfo->si_status = p->p_xstat;
 1191                                 siginfo->si_code = CLD_TRAPPED;
 1192                         }
 1193                         if ((options & WNOWAIT) == 0) {
 1194                                 PROC_LOCK(q);
 1195                                 sigqueue_take(p->p_ksi);
 1196                                 PROC_UNLOCK(q);
 1197                         }
 1198 
 1199                         CTR4(KTR_PTRACE,
 1200             "wait: returning trapped pid %d status %#x (xstat %d) xthread %d",
 1201                             p->p_pid, W_STOPCODE(p->p_xstat), p->p_xstat,
 1202                             p->p_xthread != NULL ? p->p_xthread->td_tid : -1);
 1203                         PROC_UNLOCK(p);
 1204                         return (0);
 1205                 }
 1206                 if ((options & WUNTRACED) != 0 &&
 1207                     (p->p_flag & P_STOPPED_SIG) != 0 &&
 1208                     (p->p_suspcount == p->p_numthreads) &&
 1209                     ((p->p_flag & P_WAITED) == 0)) {
 1210                         PROC_SUNLOCK(p);
 1211                         if ((options & WNOWAIT) == 0)
 1212                                 p->p_flag |= P_WAITED;
 1213                         sx_xunlock(&proctree_lock);
 1214                         td->td_retval[0] = p->p_pid;
 1215 
 1216                         if (status != NULL)
 1217                                 *status = W_STOPCODE(p->p_xstat);
 1218                         if (siginfo != NULL) {
 1219                                 siginfo->si_status = p->p_xstat;
 1220                                 siginfo->si_code = CLD_STOPPED;
 1221                         }
 1222                         if ((options & WNOWAIT) == 0) {
 1223                                 PROC_LOCK(q);
 1224                                 sigqueue_take(p->p_ksi);
 1225                                 PROC_UNLOCK(q);
 1226                         }
 1227 
 1228                         PROC_UNLOCK(p);
 1229                         return (0);
 1230                 }
 1231                 PROC_SUNLOCK(p);
 1232                 if ((options & WCONTINUED) != 0 &&
 1233                     (p->p_flag & P_CONTINUED) != 0) {
 1234                         sx_xunlock(&proctree_lock);
 1235                         td->td_retval[0] = p->p_pid;
 1236                         if ((options & WNOWAIT) == 0) {
 1237                                 p->p_flag &= ~P_CONTINUED;
 1238                                 PROC_LOCK(q);
 1239                                 sigqueue_take(p->p_ksi);
 1240                                 PROC_UNLOCK(q);
 1241                         }
 1242                         PROC_UNLOCK(p);
 1243 
 1244                         if (status != NULL)
 1245                                 *status = SIGCONT;
 1246                         if (siginfo != NULL) {
 1247                                 siginfo->si_status = SIGCONT;
 1248                                 siginfo->si_code = CLD_CONTINUED;
 1249                         }
 1250                         return (0);
 1251                 }
 1252                 PROC_UNLOCK(p);
 1253         }
 1254 
 1255         /*
 1256          * Look in the orphans list too, to allow the parent to
 1257          * collect it's child exit status even if child is being
 1258          * debugged.
 1259          *
 1260          * Debugger detaches from the parent upon successful
 1261          * switch-over from parent to child.  At this point due to
 1262          * re-parenting the parent loses the child to debugger and a
 1263          * wait4(2) call would report that it has no children to wait
 1264          * for.  By maintaining a list of orphans we allow the parent
 1265          * to successfully wait until the child becomes a zombie.
 1266          */
 1267         if (nfound == 0) {
 1268                 LIST_FOREACH(p, &q->p_orphans, p_orphan) {
 1269                         ret = proc_to_reap(td, p, idtype, id, NULL, options,
 1270                             NULL, NULL, 1);
 1271                         if (ret != 0) {
 1272                                 KASSERT(ret != -1, ("reaped an orphan (pid %d)",
 1273                                     (int)td->td_retval[0]));
 1274                                 nfound++;
 1275                                 break;
 1276                         }
 1277                 }
 1278         }
 1279         if (nfound == 0) {
 1280                 sx_xunlock(&proctree_lock);
 1281                 return (ECHILD);
 1282         }
 1283         if (options & WNOHANG) {
 1284                 sx_xunlock(&proctree_lock);
 1285                 td->td_retval[0] = 0;
 1286                 return (0);
 1287         }
 1288         PROC_LOCK(q);
 1289         sx_xunlock(&proctree_lock);
 1290         if (q->p_flag & P_STATCHILD) {
 1291                 q->p_flag &= ~P_STATCHILD;
 1292                 error = 0;
 1293         } else
 1294                 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
 1295         PROC_UNLOCK(q);
 1296         if (error)
 1297                 return (error);
 1298         goto loop;
 1299 }
 1300 
 1301 /*
 1302  * Make process 'parent' the new parent of process 'child'.
 1303  * Must be called with an exclusive hold of proctree lock.
 1304  */
 1305 void
 1306 proc_reparent(struct proc *child, struct proc *parent)
 1307 {
 1308 
 1309         sx_assert(&proctree_lock, SX_XLOCKED);
 1310         PROC_LOCK_ASSERT(child, MA_OWNED);
 1311         if (child->p_pptr == parent)
 1312                 return;
 1313 
 1314         PROC_LOCK(child->p_pptr);
 1315         sigqueue_take(child->p_ksi);
 1316         PROC_UNLOCK(child->p_pptr);
 1317         LIST_REMOVE(child, p_sibling);
 1318         LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
 1319 
 1320         clear_orphan(child);
 1321         if (child->p_flag & P_TRACED) {
 1322                 if (LIST_EMPTY(&child->p_pptr->p_orphans)) {
 1323                         child->p_treeflag |= P_TREE_FIRST_ORPHAN;
 1324                         LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child,
 1325                             p_orphan);
 1326                 } else {
 1327                         LIST_INSERT_AFTER(LIST_FIRST(&child->p_pptr->p_orphans),
 1328                             child, p_orphan);
 1329                 }
 1330                 child->p_treeflag |= P_TREE_ORPHANED;
 1331         }
 1332 
 1333         child->p_pptr = parent;
 1334 }

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