xref: /freebsd/sys/kern/kern_exit.c (revision 9fe48b8076ae9c6dc486d713c468ff03ec056eda)
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_ktrace.h"
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/sysproto.h>
46 #include <sys/capsicum.h>
47 #include <sys/eventhandler.h>
48 #include <sys/kernel.h>
49 #include <sys/malloc.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/proc.h>
53 #include <sys/procdesc.h>
54 #include <sys/pioctl.h>
55 #include <sys/jail.h>
56 #include <sys/tty.h>
57 #include <sys/wait.h>
58 #include <sys/vmmeter.h>
59 #include <sys/vnode.h>
60 #include <sys/racct.h>
61 #include <sys/resourcevar.h>
62 #include <sys/sbuf.h>
63 #include <sys/signalvar.h>
64 #include <sys/sched.h>
65 #include <sys/sx.h>
66 #include <sys/syscallsubr.h>
67 #include <sys/syslog.h>
68 #include <sys/ptrace.h>
69 #include <sys/acct.h>		/* for acct_process() function prototype */
70 #include <sys/filedesc.h>
71 #include <sys/sdt.h>
72 #include <sys/shm.h>
73 #include <sys/sem.h>
74 #include <sys/umtx.h>
75 #ifdef KTRACE
76 #include <sys/ktrace.h>
77 #endif
78 
79 #include <security/audit/audit.h>
80 #include <security/mac/mac_framework.h>
81 
82 #include <vm/vm.h>
83 #include <vm/vm_extern.h>
84 #include <vm/vm_param.h>
85 #include <vm/pmap.h>
86 #include <vm/vm_map.h>
87 #include <vm/vm_page.h>
88 #include <vm/uma.h>
89 
90 #ifdef KDTRACE_HOOKS
91 #include <sys/dtrace_bsd.h>
92 dtrace_execexit_func_t	dtrace_fasttrap_exit;
93 #endif
94 
95 SDT_PROVIDER_DECLARE(proc);
96 SDT_PROBE_DEFINE1(proc, kernel, , exit, "int");
97 
98 /* Hook for NFS teardown procedure. */
99 void (*nlminfo_release_p)(struct proc *p);
100 
101 struct proc *
102 proc_realparent(struct proc *child)
103 {
104 	struct proc *p, *parent;
105 
106 	sx_assert(&proctree_lock, SX_LOCKED);
107 	if ((child->p_treeflag & P_TREE_ORPHANED) == 0) {
108 		if (child->p_oppid == 0 ||
109 		    child->p_pptr->p_pid == child->p_oppid)
110 			parent = child->p_pptr;
111 		else
112 			parent = initproc;
113 		return (parent);
114 	}
115 	for (p = child; (p->p_treeflag & P_TREE_FIRST_ORPHAN) == 0;) {
116 		/* Cannot use LIST_PREV(), since the list head is not known. */
117 		p = __containerof(p->p_orphan.le_prev, struct proc,
118 		    p_orphan.le_next);
119 		KASSERT((p->p_treeflag & P_TREE_ORPHANED) != 0,
120 		    ("missing P_ORPHAN %p", p));
121 	}
122 	parent = __containerof(p->p_orphan.le_prev, struct proc,
123 	    p_orphans.lh_first);
124 	return (parent);
125 }
126 
127 void
128 reaper_abandon_children(struct proc *p, bool exiting)
129 {
130 	struct proc *p1, *p2, *ptmp;
131 
132 	sx_assert(&proctree_lock, SX_LOCKED);
133 	KASSERT(p != initproc, ("reaper_abandon_children for initproc"));
134 	if ((p->p_treeflag & P_TREE_REAPER) == 0)
135 		return;
136 	p1 = p->p_reaper;
137 	LIST_FOREACH_SAFE(p2, &p->p_reaplist, p_reapsibling, ptmp) {
138 		LIST_REMOVE(p2, p_reapsibling);
139 		p2->p_reaper = p1;
140 		p2->p_reapsubtree = p->p_reapsubtree;
141 		LIST_INSERT_HEAD(&p1->p_reaplist, p2, p_reapsibling);
142 		if (exiting && p2->p_pptr == p) {
143 			PROC_LOCK(p2);
144 			proc_reparent(p2, p1);
145 			PROC_UNLOCK(p2);
146 		}
147 	}
148 	KASSERT(LIST_EMPTY(&p->p_reaplist), ("p_reaplist not empty"));
149 	p->p_treeflag &= ~P_TREE_REAPER;
150 }
151 
152 static void
153 clear_orphan(struct proc *p)
154 {
155 	struct proc *p1;
156 
157 	sx_assert(&proctree_lock, SA_XLOCKED);
158 	if ((p->p_treeflag & P_TREE_ORPHANED) == 0)
159 		return;
160 	if ((p->p_treeflag & P_TREE_FIRST_ORPHAN) != 0) {
161 		p1 = LIST_NEXT(p, p_orphan);
162 		if (p1 != NULL)
163 			p1->p_treeflag |= P_TREE_FIRST_ORPHAN;
164 		p->p_treeflag &= ~P_TREE_FIRST_ORPHAN;
165 	}
166 	LIST_REMOVE(p, p_orphan);
167 	p->p_treeflag &= ~P_TREE_ORPHANED;
168 }
169 
170 /*
171  * exit -- death of process.
172  */
173 void
174 sys_sys_exit(struct thread *td, struct sys_exit_args *uap)
175 {
176 
177 	exit1(td, W_EXITCODE(uap->rval, 0));
178 	/* NOTREACHED */
179 }
180 
181 /*
182  * Exit: deallocate address space and other resources, change proc state to
183  * zombie, and unlink proc from allproc and parent's lists.  Save exit status
184  * and rusage for wait().  Check for child processes and orphan them.
185  */
186 void
187 exit1(struct thread *td, int rv)
188 {
189 	struct proc *p, *nq, *q, *t;
190 	struct thread *tdt;
191 	struct vnode *ttyvp = NULL;
192 
193 	mtx_assert(&Giant, MA_NOTOWNED);
194 
195 	p = td->td_proc;
196 	/*
197 	 * XXX in case we're rebooting we just let init die in order to
198 	 * work around an unsolved stack overflow seen very late during
199 	 * shutdown on sparc64 when the gmirror worker process exists.
200 	 */
201 	if (p == initproc && rebooting == 0) {
202 		printf("init died (signal %d, exit %d)\n",
203 		    WTERMSIG(rv), WEXITSTATUS(rv));
204 		panic("Going nowhere without my init!");
205 	}
206 
207 	/*
208 	 * MUST abort all other threads before proceeding past here.
209 	 */
210 	PROC_LOCK(p);
211 	/*
212 	 * First check if some other thread or external request got
213 	 * here before us.  If so, act appropriately: exit or suspend.
214 	 * We must ensure that stop requests are handled before we set
215 	 * P_WEXIT.
216 	 */
217 	thread_suspend_check(0);
218 	while (p->p_flag & P_HADTHREADS) {
219 		/*
220 		 * Kill off the other threads. This requires
221 		 * some co-operation from other parts of the kernel
222 		 * so it may not be instantaneous.  With this state set
223 		 * any thread entering the kernel from userspace will
224 		 * thread_exit() in trap().  Any thread attempting to
225 		 * sleep will return immediately with EINTR or EWOULDBLOCK
226 		 * which will hopefully force them to back out to userland
227 		 * freeing resources as they go.  Any thread attempting
228 		 * to return to userland will thread_exit() from userret().
229 		 * thread_exit() will unsuspend us when the last of the
230 		 * other threads exits.
231 		 * If there is already a thread singler after resumption,
232 		 * calling thread_single will fail; in that case, we just
233 		 * re-check all suspension request, the thread should
234 		 * either be suspended there or exit.
235 		 */
236 		if (!thread_single(p, SINGLE_EXIT))
237 			/*
238 			 * All other activity in this process is now
239 			 * stopped.  Threading support has been turned
240 			 * off.
241 			 */
242 			break;
243 		/*
244 		 * Recheck for new stop or suspend requests which
245 		 * might appear while process lock was dropped in
246 		 * thread_single().
247 		 */
248 		thread_suspend_check(0);
249 	}
250 	KASSERT(p->p_numthreads == 1,
251 	    ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
252 	racct_sub(p, RACCT_NTHR, 1);
253 	/*
254 	 * Wakeup anyone in procfs' PIOCWAIT.  They should have a hold
255 	 * on our vmspace, so we should block below until they have
256 	 * released their reference to us.  Note that if they have
257 	 * requested S_EXIT stops we will block here until they ack
258 	 * via PIOCCONT.
259 	 */
260 	_STOPEVENT(p, S_EXIT, rv);
261 
262 	/*
263 	 * Ignore any pending request to stop due to a stop signal.
264 	 * Once P_WEXIT is set, future requests will be ignored as
265 	 * well.
266 	 */
267 	p->p_flag &= ~P_STOPPED_SIG;
268 	KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped"));
269 
270 	/*
271 	 * Note that we are exiting and do another wakeup of anyone in
272 	 * PIOCWAIT in case they aren't listening for S_EXIT stops or
273 	 * decided to wait again after we told them we are exiting.
274 	 */
275 	p->p_flag |= P_WEXIT;
276 	wakeup(&p->p_stype);
277 
278 	/*
279 	 * Wait for any processes that have a hold on our vmspace to
280 	 * release their reference.
281 	 */
282 	while (p->p_lock > 0)
283 		msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
284 
285 	p->p_xstat = rv;	/* Let event handler change exit status */
286 	PROC_UNLOCK(p);
287 	/* Drain the limit callout while we don't have the proc locked */
288 	callout_drain(&p->p_limco);
289 
290 #ifdef AUDIT
291 	/*
292 	 * The Sun BSM exit token contains two components: an exit status as
293 	 * passed to exit(), and a return value to indicate what sort of exit
294 	 * it was.  The exit status is WEXITSTATUS(rv), but it's not clear
295 	 * what the return value is.
296 	 */
297 	AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0);
298 	AUDIT_SYSCALL_EXIT(0, td);
299 #endif
300 
301 	/* Are we a task leader with peers? */
302 	if (p->p_peers != NULL && p == p->p_leader) {
303 		mtx_lock(&ppeers_lock);
304 		q = p->p_peers;
305 		while (q != NULL) {
306 			PROC_LOCK(q);
307 			kern_psignal(q, SIGKILL);
308 			PROC_UNLOCK(q);
309 			q = q->p_peers;
310 		}
311 		while (p->p_peers != NULL)
312 			msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
313 		mtx_unlock(&ppeers_lock);
314 	}
315 
316 	/*
317 	 * Check if any loadable modules need anything done at process exit.
318 	 * E.g. SYSV IPC stuff
319 	 * XXX what if one of these generates an error?
320 	 */
321 	EVENTHANDLER_INVOKE(process_exit, p);
322 
323 	/*
324 	 * If parent is waiting for us to exit or exec,
325 	 * P_PPWAIT is set; we will wakeup the parent below.
326 	 */
327 	PROC_LOCK(p);
328 	rv = p->p_xstat;	/* Event handler could change exit status */
329 	stopprofclock(p);
330 	p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE);
331 
332 	/*
333 	 * Stop the real interval timer.  If the handler is currently
334 	 * executing, prevent it from rearming itself and let it finish.
335 	 */
336 	if (timevalisset(&p->p_realtimer.it_value) &&
337 	    callout_stop(&p->p_itcallout) == 0) {
338 		timevalclear(&p->p_realtimer.it_interval);
339 		msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
340 		KASSERT(!timevalisset(&p->p_realtimer.it_value),
341 		    ("realtime timer is still armed"));
342 	}
343 	PROC_UNLOCK(p);
344 
345 	/*
346 	 * Reset any sigio structures pointing to us as a result of
347 	 * F_SETOWN with our pid.
348 	 */
349 	funsetownlst(&p->p_sigiolst);
350 
351 	/*
352 	 * If this process has an nlminfo data area (for lockd), release it
353 	 */
354 	if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
355 		(*nlminfo_release_p)(p);
356 
357 	/*
358 	 * Close open files and release open-file table.
359 	 * This may block!
360 	 */
361 	fdescfree(td);
362 
363 	/*
364 	 * If this thread tickled GEOM, we need to wait for the giggling to
365 	 * stop before we return to userland
366 	 */
367 	if (td->td_pflags & TDP_GEOM)
368 		g_waitidle();
369 
370 	/*
371 	 * Remove ourself from our leader's peer list and wake our leader.
372 	 */
373 	if (p->p_leader->p_peers != NULL) {
374 		mtx_lock(&ppeers_lock);
375 		if (p->p_leader->p_peers != NULL) {
376 			q = p->p_leader;
377 			while (q->p_peers != p)
378 				q = q->p_peers;
379 			q->p_peers = p->p_peers;
380 			wakeup(p->p_leader);
381 		}
382 		mtx_unlock(&ppeers_lock);
383 	}
384 
385 	vmspace_exit(td);
386 
387 	sx_xlock(&proctree_lock);
388 	if (SESS_LEADER(p)) {
389 		struct session *sp = p->p_session;
390 		struct tty *tp;
391 
392 		/*
393 		 * s_ttyp is not zero'd; we use this to indicate that
394 		 * the session once had a controlling terminal. (for
395 		 * logging and informational purposes)
396 		 */
397 		SESS_LOCK(sp);
398 		ttyvp = sp->s_ttyvp;
399 		tp = sp->s_ttyp;
400 		sp->s_ttyvp = NULL;
401 		sp->s_ttydp = NULL;
402 		sp->s_leader = NULL;
403 		SESS_UNLOCK(sp);
404 
405 		/*
406 		 * Signal foreground pgrp and revoke access to
407 		 * controlling terminal if it has not been revoked
408 		 * already.
409 		 *
410 		 * Because the TTY may have been revoked in the mean
411 		 * time and could already have a new session associated
412 		 * with it, make sure we don't send a SIGHUP to a
413 		 * foreground process group that does not belong to this
414 		 * session.
415 		 */
416 
417 		if (tp != NULL) {
418 			tty_lock(tp);
419 			if (tp->t_session == sp)
420 				tty_signal_pgrp(tp, SIGHUP);
421 			tty_unlock(tp);
422 		}
423 
424 		if (ttyvp != NULL) {
425 			sx_xunlock(&proctree_lock);
426 			if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) {
427 				VOP_REVOKE(ttyvp, REVOKEALL);
428 				VOP_UNLOCK(ttyvp, 0);
429 			}
430 			sx_xlock(&proctree_lock);
431 		}
432 	}
433 	fixjobc(p, p->p_pgrp, 0);
434 	sx_xunlock(&proctree_lock);
435 	(void)acct_process(td);
436 
437 	/* Release the TTY now we've unlocked everything. */
438 	if (ttyvp != NULL)
439 		vrele(ttyvp);
440 #ifdef KTRACE
441 	ktrprocexit(td);
442 #endif
443 	/*
444 	 * Release reference to text vnode
445 	 */
446 	if (p->p_textvp != NULL) {
447 		vrele(p->p_textvp);
448 		p->p_textvp = NULL;
449 	}
450 
451 	/*
452 	 * Release our limits structure.
453 	 */
454 	lim_free(p->p_limit);
455 	p->p_limit = NULL;
456 
457 	tidhash_remove(td);
458 
459 	/*
460 	 * Remove proc from allproc queue and pidhash chain.
461 	 * Place onto zombproc.  Unlink from parent's child list.
462 	 */
463 	sx_xlock(&allproc_lock);
464 	LIST_REMOVE(p, p_list);
465 	LIST_INSERT_HEAD(&zombproc, p, p_list);
466 	LIST_REMOVE(p, p_hash);
467 	sx_xunlock(&allproc_lock);
468 
469 	/*
470 	 * Call machine-dependent code to release any
471 	 * machine-dependent resources other than the address space.
472 	 * The address space is released by "vmspace_exitfree(p)" in
473 	 * vm_waitproc().
474 	 */
475 	cpu_exit(td);
476 
477 	WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
478 
479 	/*
480 	 * Reparent all children processes:
481 	 * - traced ones to the original parent (or init if we are that parent)
482 	 * - the rest to init
483 	 */
484 	sx_xlock(&proctree_lock);
485 	q = LIST_FIRST(&p->p_children);
486 	if (q != NULL)		/* only need this if any child is S_ZOMB */
487 		wakeup(q->p_reaper);
488 	for (; q != NULL; q = nq) {
489 		nq = LIST_NEXT(q, p_sibling);
490 		PROC_LOCK(q);
491 		q->p_sigparent = SIGCHLD;
492 
493 		if (!(q->p_flag & P_TRACED)) {
494 			proc_reparent(q, q->p_reaper);
495 		} else {
496 			/*
497 			 * Traced processes are killed since their existence
498 			 * means someone is screwing up.
499 			 */
500 			t = proc_realparent(q);
501 			if (t == p) {
502 				proc_reparent(q, q->p_reaper);
503 			} else {
504 				PROC_LOCK(t);
505 				proc_reparent(q, t);
506 				PROC_UNLOCK(t);
507 			}
508 			/*
509 			 * Since q was found on our children list, the
510 			 * proc_reparent() call moved q to the orphan
511 			 * list due to present P_TRACED flag. Clear
512 			 * orphan link for q now while q is locked.
513 			 */
514 			clear_orphan(q);
515 			q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
516 			FOREACH_THREAD_IN_PROC(q, tdt)
517 				tdt->td_dbgflags &= ~TDB_SUSPEND;
518 			kern_psignal(q, SIGKILL);
519 		}
520 		PROC_UNLOCK(q);
521 	}
522 
523 	/*
524 	 * Also get rid of our orphans.
525 	 */
526 	while ((q = LIST_FIRST(&p->p_orphans)) != NULL) {
527 		PROC_LOCK(q);
528 		clear_orphan(q);
529 		PROC_UNLOCK(q);
530 	}
531 
532 	/* Save exit status. */
533 	PROC_LOCK(p);
534 	p->p_xthread = td;
535 
536 	/* Tell the prison that we are gone. */
537 	prison_proc_free(p->p_ucred->cr_prison);
538 
539 #ifdef KDTRACE_HOOKS
540 	/*
541 	 * Tell the DTrace fasttrap provider about the exit if it
542 	 * has declared an interest.
543 	 */
544 	if (dtrace_fasttrap_exit)
545 		dtrace_fasttrap_exit(p);
546 #endif
547 
548 	/*
549 	 * Notify interested parties of our demise.
550 	 */
551 	KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
552 
553 #ifdef KDTRACE_HOOKS
554 	int reason = CLD_EXITED;
555 	if (WCOREDUMP(rv))
556 		reason = CLD_DUMPED;
557 	else if (WIFSIGNALED(rv))
558 		reason = CLD_KILLED;
559 	SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0);
560 #endif
561 
562 	/*
563 	 * Just delete all entries in the p_klist. At this point we won't
564 	 * report any more events, and there are nasty race conditions that
565 	 * can beat us if we don't.
566 	 */
567 	knlist_clear(&p->p_klist, 1);
568 
569 	/*
570 	 * If this is a process with a descriptor, we may not need to deliver
571 	 * a signal to the parent.  proctree_lock is held over
572 	 * procdesc_exit() to serialize concurrent calls to close() and
573 	 * exit().
574 	 */
575 	if (p->p_procdesc == NULL || procdesc_exit(p)) {
576 		/*
577 		 * Notify parent that we're gone.  If parent has the
578 		 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN,
579 		 * notify process 1 instead (and hope it will handle this
580 		 * situation).
581 		 */
582 		PROC_LOCK(p->p_pptr);
583 		mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
584 		if (p->p_pptr->p_sigacts->ps_flag &
585 		    (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
586 			struct proc *pp;
587 
588 			mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
589 			pp = p->p_pptr;
590 			PROC_UNLOCK(pp);
591 			proc_reparent(p, p->p_reaper);
592 			p->p_sigparent = SIGCHLD;
593 			PROC_LOCK(p->p_pptr);
594 
595 			/*
596 			 * Notify parent, so in case he was wait(2)ing or
597 			 * executing waitpid(2) with our pid, he will
598 			 * continue.
599 			 */
600 			wakeup(pp);
601 		} else
602 			mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
603 
604 		if (p->p_pptr == p->p_reaper || p->p_pptr == initproc)
605 			childproc_exited(p);
606 		else if (p->p_sigparent != 0) {
607 			if (p->p_sigparent == SIGCHLD)
608 				childproc_exited(p);
609 			else	/* LINUX thread */
610 				kern_psignal(p->p_pptr, p->p_sigparent);
611 		}
612 	} else
613 		PROC_LOCK(p->p_pptr);
614 	sx_xunlock(&proctree_lock);
615 
616 	/*
617 	 * The state PRS_ZOMBIE prevents other proesses from sending
618 	 * signal to the process, to avoid memory leak, we free memory
619 	 * for signal queue at the time when the state is set.
620 	 */
621 	sigqueue_flush(&p->p_sigqueue);
622 	sigqueue_flush(&td->td_sigqueue);
623 
624 	/*
625 	 * We have to wait until after acquiring all locks before
626 	 * changing p_state.  We need to avoid all possible context
627 	 * switches (including ones from blocking on a mutex) while
628 	 * marked as a zombie.  We also have to set the zombie state
629 	 * before we release the parent process' proc lock to avoid
630 	 * a lost wakeup.  So, we first call wakeup, then we grab the
631 	 * sched lock, update the state, and release the parent process'
632 	 * proc lock.
633 	 */
634 	wakeup(p->p_pptr);
635 	cv_broadcast(&p->p_pwait);
636 	sched_exit(p->p_pptr, td);
637 	umtx_thread_exit(td);
638 	PROC_SLOCK(p);
639 	p->p_state = PRS_ZOMBIE;
640 	PROC_UNLOCK(p->p_pptr);
641 
642 	/*
643 	 * Hopefully no one will try to deliver a signal to the process this
644 	 * late in the game.
645 	 */
646 	knlist_destroy(&p->p_klist);
647 
648 	/*
649 	 * Save our children's rusage information in our exit rusage.
650 	 */
651 	PROC_STATLOCK(p);
652 	ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
653 	PROC_STATUNLOCK(p);
654 
655 	/*
656 	 * Make sure the scheduler takes this thread out of its tables etc.
657 	 * This will also release this thread's reference to the ucred.
658 	 * Other thread parts to release include pcb bits and such.
659 	 */
660 	thread_exit();
661 }
662 
663 
664 #ifndef _SYS_SYSPROTO_H_
665 struct abort2_args {
666 	char *why;
667 	int nargs;
668 	void **args;
669 };
670 #endif
671 
672 int
673 sys_abort2(struct thread *td, struct abort2_args *uap)
674 {
675 	struct proc *p = td->td_proc;
676 	struct sbuf *sb;
677 	void *uargs[16];
678 	int error, i, sig;
679 
680 	/*
681 	 * Do it right now so we can log either proper call of abort2(), or
682 	 * note, that invalid argument was passed. 512 is big enough to
683 	 * handle 16 arguments' descriptions with additional comments.
684 	 */
685 	sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
686 	sbuf_clear(sb);
687 	sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
688 	    p->p_comm, p->p_pid, td->td_ucred->cr_uid);
689 	/*
690 	 * Since we can't return from abort2(), send SIGKILL in cases, where
691 	 * abort2() was called improperly
692 	 */
693 	sig = SIGKILL;
694 	/* Prevent from DoSes from user-space. */
695 	if (uap->nargs < 0 || uap->nargs > 16)
696 		goto out;
697 	if (uap->nargs > 0) {
698 		if (uap->args == NULL)
699 			goto out;
700 		error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
701 		if (error != 0)
702 			goto out;
703 	}
704 	/*
705 	 * Limit size of 'reason' string to 128. Will fit even when
706 	 * maximal number of arguments was chosen to be logged.
707 	 */
708 	if (uap->why != NULL) {
709 		error = sbuf_copyin(sb, uap->why, 128);
710 		if (error < 0)
711 			goto out;
712 	} else {
713 		sbuf_printf(sb, "(null)");
714 	}
715 	if (uap->nargs > 0) {
716 		sbuf_printf(sb, "(");
717 		for (i = 0;i < uap->nargs; i++)
718 			sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
719 		sbuf_printf(sb, ")");
720 	}
721 	/*
722 	 * Final stage: arguments were proper, string has been
723 	 * successfully copied from userspace, and copying pointers
724 	 * from user-space succeed.
725 	 */
726 	sig = SIGABRT;
727 out:
728 	if (sig == SIGKILL) {
729 		sbuf_trim(sb);
730 		sbuf_printf(sb, " (Reason text inaccessible)");
731 	}
732 	sbuf_cat(sb, "\n");
733 	sbuf_finish(sb);
734 	log(LOG_INFO, "%s", sbuf_data(sb));
735 	sbuf_delete(sb);
736 	exit1(td, W_EXITCODE(0, sig));
737 	return (0);
738 }
739 
740 
741 #ifdef COMPAT_43
742 /*
743  * The dirty work is handled by kern_wait().
744  */
745 int
746 owait(struct thread *td, struct owait_args *uap __unused)
747 {
748 	int error, status;
749 
750 	error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
751 	if (error == 0)
752 		td->td_retval[1] = status;
753 	return (error);
754 }
755 #endif /* COMPAT_43 */
756 
757 /*
758  * The dirty work is handled by kern_wait().
759  */
760 int
761 sys_wait4(struct thread *td, struct wait4_args *uap)
762 {
763 	struct rusage ru, *rup;
764 	int error, status;
765 
766 	if (uap->rusage != NULL)
767 		rup = &ru;
768 	else
769 		rup = NULL;
770 	error = kern_wait(td, uap->pid, &status, uap->options, rup);
771 	if (uap->status != NULL && error == 0)
772 		error = copyout(&status, uap->status, sizeof(status));
773 	if (uap->rusage != NULL && error == 0)
774 		error = copyout(&ru, uap->rusage, sizeof(struct rusage));
775 	return (error);
776 }
777 
778 int
779 sys_wait6(struct thread *td, struct wait6_args *uap)
780 {
781 	struct __wrusage wru, *wrup;
782 	siginfo_t si, *sip;
783 	idtype_t idtype;
784 	id_t id;
785 	int error, status;
786 
787 	idtype = uap->idtype;
788 	id = uap->id;
789 
790 	if (uap->wrusage != NULL)
791 		wrup = &wru;
792 	else
793 		wrup = NULL;
794 
795 	if (uap->info != NULL) {
796 		sip = &si;
797 		bzero(sip, sizeof(*sip));
798 	} else
799 		sip = NULL;
800 
801 	/*
802 	 *  We expect all callers of wait6() to know about WEXITED and
803 	 *  WTRAPPED.
804 	 */
805 	error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip);
806 
807 	if (uap->status != NULL && error == 0)
808 		error = copyout(&status, uap->status, sizeof(status));
809 	if (uap->wrusage != NULL && error == 0)
810 		error = copyout(&wru, uap->wrusage, sizeof(wru));
811 	if (uap->info != NULL && error == 0)
812 		error = copyout(&si, uap->info, sizeof(si));
813 	return (error);
814 }
815 
816 /*
817  * Reap the remains of a zombie process and optionally return status and
818  * rusage.  Asserts and will release both the proctree_lock and the process
819  * lock as part of its work.
820  */
821 void
822 proc_reap(struct thread *td, struct proc *p, int *status, int options)
823 {
824 	struct proc *q, *t;
825 
826 	sx_assert(&proctree_lock, SA_XLOCKED);
827 	PROC_LOCK_ASSERT(p, MA_OWNED);
828 	PROC_SLOCK_ASSERT(p, MA_OWNED);
829 	KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
830 
831 	q = td->td_proc;
832 
833 	PROC_SUNLOCK(p);
834 	td->td_retval[0] = p->p_pid;
835 	if (status)
836 		*status = p->p_xstat;	/* convert to int */
837 	if (options & WNOWAIT) {
838 		/*
839 		 *  Only poll, returning the status.  Caller does not wish to
840 		 * release the proc struct just yet.
841 		 */
842 		PROC_UNLOCK(p);
843 		sx_xunlock(&proctree_lock);
844 		return;
845 	}
846 
847 	PROC_LOCK(q);
848 	sigqueue_take(p->p_ksi);
849 	PROC_UNLOCK(q);
850 	PROC_UNLOCK(p);
851 
852 	/*
853 	 * If we got the child via a ptrace 'attach', we need to give it back
854 	 * to the old parent.
855 	 */
856 	if (p->p_oppid != 0) {
857 		t = proc_realparent(p);
858 		PROC_LOCK(t);
859 		PROC_LOCK(p);
860 		proc_reparent(p, t);
861 		p->p_oppid = 0;
862 		PROC_UNLOCK(p);
863 		pksignal(t, SIGCHLD, p->p_ksi);
864 		wakeup(t);
865 		cv_broadcast(&p->p_pwait);
866 		PROC_UNLOCK(t);
867 		sx_xunlock(&proctree_lock);
868 		return;
869 	}
870 
871 	/*
872 	 * Remove other references to this process to ensure we have an
873 	 * exclusive reference.
874 	 */
875 	sx_xlock(&allproc_lock);
876 	LIST_REMOVE(p, p_list);	/* off zombproc */
877 	sx_xunlock(&allproc_lock);
878 	LIST_REMOVE(p, p_sibling);
879 	reaper_abandon_children(p, true);
880 	LIST_REMOVE(p, p_reapsibling);
881 	PROC_LOCK(p);
882 	clear_orphan(p);
883 	PROC_UNLOCK(p);
884 	leavepgrp(p);
885 	if (p->p_procdesc != NULL)
886 		procdesc_reap(p);
887 	sx_xunlock(&proctree_lock);
888 
889 	/*
890 	 * Removal from allproc list and process group list paired with
891 	 * PROC_LOCK which was executed during that time should guarantee
892 	 * nothing can reach this process anymore. As such further locking
893 	 * is unnecessary.
894 	 */
895 	p->p_xstat = 0;		/* XXX: why? */
896 
897 	PROC_LOCK(q);
898 	ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
899 	PROC_UNLOCK(q);
900 
901 	/*
902 	 * Decrement the count of procs running with this uid.
903 	 */
904 	(void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
905 
906 	/*
907 	 * Destroy resource accounting information associated with the process.
908 	 */
909 #ifdef RACCT
910 	if (racct_enable) {
911 		PROC_LOCK(p);
912 		racct_sub(p, RACCT_NPROC, 1);
913 		PROC_UNLOCK(p);
914 	}
915 #endif
916 	racct_proc_exit(p);
917 
918 	/*
919 	 * Free credentials, arguments, and sigacts.
920 	 */
921 	crfree(p->p_ucred);
922 	proc_set_cred(p, NULL);
923 	pargs_drop(p->p_args);
924 	p->p_args = NULL;
925 	sigacts_free(p->p_sigacts);
926 	p->p_sigacts = NULL;
927 
928 	/*
929 	 * Do any thread-system specific cleanups.
930 	 */
931 	thread_wait(p);
932 
933 	/*
934 	 * Give vm and machine-dependent layer a chance to free anything that
935 	 * cpu_exit couldn't release while still running in process context.
936 	 */
937 	vm_waitproc(p);
938 #ifdef MAC
939 	mac_proc_destroy(p);
940 #endif
941 	KASSERT(FIRST_THREAD_IN_PROC(p),
942 	    ("proc_reap: no residual thread!"));
943 	uma_zfree(proc_zone, p);
944 	sx_xlock(&allproc_lock);
945 	nprocs--;
946 	sx_xunlock(&allproc_lock);
947 }
948 
949 static int
950 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
951     int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo)
952 {
953 	struct proc *q;
954 	struct rusage *rup;
955 
956 	sx_assert(&proctree_lock, SA_XLOCKED);
957 
958 	q = td->td_proc;
959 	PROC_LOCK(p);
960 
961 	switch (idtype) {
962 	case P_ALL:
963 		break;
964 	case P_PID:
965 		if (p->p_pid != (pid_t)id) {
966 			PROC_UNLOCK(p);
967 			return (0);
968 		}
969 		break;
970 	case P_PGID:
971 		if (p->p_pgid != (pid_t)id) {
972 			PROC_UNLOCK(p);
973 			return (0);
974 		}
975 		break;
976 	case P_SID:
977 		if (p->p_session->s_sid != (pid_t)id) {
978 			PROC_UNLOCK(p);
979 			return (0);
980 		}
981 		break;
982 	case P_UID:
983 		if (p->p_ucred->cr_uid != (uid_t)id) {
984 			PROC_UNLOCK(p);
985 			return (0);
986 		}
987 		break;
988 	case P_GID:
989 		if (p->p_ucred->cr_gid != (gid_t)id) {
990 			PROC_UNLOCK(p);
991 			return (0);
992 		}
993 		break;
994 	case P_JAILID:
995 		if (p->p_ucred->cr_prison->pr_id != (int)id) {
996 			PROC_UNLOCK(p);
997 			return (0);
998 		}
999 		break;
1000 	/*
1001 	 * It seems that the thread structures get zeroed out
1002 	 * at process exit.  This makes it impossible to
1003 	 * support P_SETID, P_CID or P_CPUID.
1004 	 */
1005 	default:
1006 		PROC_UNLOCK(p);
1007 		return (0);
1008 	}
1009 
1010 	if (p_canwait(td, p)) {
1011 		PROC_UNLOCK(p);
1012 		return (0);
1013 	}
1014 
1015 	if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) {
1016 		PROC_UNLOCK(p);
1017 		return (0);
1018 	}
1019 
1020 	/*
1021 	 * This special case handles a kthread spawned by linux_clone
1022 	 * (see linux_misc.c).  The linux_wait4 and linux_waitpid
1023 	 * functions need to be able to distinguish between waiting
1024 	 * on a process and waiting on a thread.  It is a thread if
1025 	 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
1026 	 * signifies we want to wait for threads and not processes.
1027 	 */
1028 	if ((p->p_sigparent != SIGCHLD) ^
1029 	    ((options & WLINUXCLONE) != 0)) {
1030 		PROC_UNLOCK(p);
1031 		return (0);
1032 	}
1033 
1034 	if (siginfo != NULL) {
1035 		bzero(siginfo, sizeof(*siginfo));
1036 		siginfo->si_errno = 0;
1037 
1038 		/*
1039 		 * SUSv4 requires that the si_signo value is always
1040 		 * SIGCHLD. Obey it despite the rfork(2) interface
1041 		 * allows to request other signal for child exit
1042 		 * notification.
1043 		 */
1044 		siginfo->si_signo = SIGCHLD;
1045 
1046 		/*
1047 		 *  This is still a rough estimate.  We will fix the
1048 		 *  cases TRAPPED, STOPPED, and CONTINUED later.
1049 		 */
1050 		if (WCOREDUMP(p->p_xstat)) {
1051 			siginfo->si_code = CLD_DUMPED;
1052 			siginfo->si_status = WTERMSIG(p->p_xstat);
1053 		} else if (WIFSIGNALED(p->p_xstat)) {
1054 			siginfo->si_code = CLD_KILLED;
1055 			siginfo->si_status = WTERMSIG(p->p_xstat);
1056 		} else {
1057 			siginfo->si_code = CLD_EXITED;
1058 			siginfo->si_status = WEXITSTATUS(p->p_xstat);
1059 		}
1060 
1061 		siginfo->si_pid = p->p_pid;
1062 		siginfo->si_uid = p->p_ucred->cr_uid;
1063 
1064 		/*
1065 		 * The si_addr field would be useful additional
1066 		 * detail, but apparently the PC value may be lost
1067 		 * when we reach this point.  bzero() above sets
1068 		 * siginfo->si_addr to NULL.
1069 		 */
1070 	}
1071 
1072 	/*
1073 	 * There should be no reason to limit resources usage info to
1074 	 * exited processes only.  A snapshot about any resources used
1075 	 * by a stopped process may be exactly what is needed.
1076 	 */
1077 	if (wrusage != NULL) {
1078 		rup = &wrusage->wru_self;
1079 		*rup = p->p_ru;
1080 		PROC_STATLOCK(p);
1081 		calcru(p, &rup->ru_utime, &rup->ru_stime);
1082 		PROC_STATUNLOCK(p);
1083 
1084 		rup = &wrusage->wru_children;
1085 		*rup = p->p_stats->p_cru;
1086 		calccru(p, &rup->ru_utime, &rup->ru_stime);
1087 	}
1088 
1089 	if (p->p_state == PRS_ZOMBIE) {
1090 		PROC_SLOCK(p);
1091 		proc_reap(td, p, status, options);
1092 		return (-1);
1093 	}
1094 	PROC_UNLOCK(p);
1095 	return (1);
1096 }
1097 
1098 int
1099 kern_wait(struct thread *td, pid_t pid, int *status, int options,
1100     struct rusage *rusage)
1101 {
1102 	struct __wrusage wru, *wrup;
1103 	idtype_t idtype;
1104 	id_t id;
1105 	int ret;
1106 
1107 	/*
1108 	 * Translate the special pid values into the (idtype, pid)
1109 	 * pair for kern_wait6.  The WAIT_MYPGRP case is handled by
1110 	 * kern_wait6() on its own.
1111 	 */
1112 	if (pid == WAIT_ANY) {
1113 		idtype = P_ALL;
1114 		id = 0;
1115 	} else if (pid < 0) {
1116 		idtype = P_PGID;
1117 		id = (id_t)-pid;
1118 	} else {
1119 		idtype = P_PID;
1120 		id = (id_t)pid;
1121 	}
1122 
1123 	if (rusage != NULL)
1124 		wrup = &wru;
1125 	else
1126 		wrup = NULL;
1127 
1128 	/*
1129 	 * For backward compatibility we implicitly add flags WEXITED
1130 	 * and WTRAPPED here.
1131 	 */
1132 	options |= WEXITED | WTRAPPED;
1133 	ret = kern_wait6(td, idtype, id, status, options, wrup, NULL);
1134 	if (rusage != NULL)
1135 		*rusage = wru.wru_self;
1136 	return (ret);
1137 }
1138 
1139 int
1140 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status,
1141     int options, struct __wrusage *wrusage, siginfo_t *siginfo)
1142 {
1143 	struct proc *p, *q;
1144 	int error, nfound, ret;
1145 
1146 	AUDIT_ARG_VALUE((int)idtype);	/* XXX - This is likely wrong! */
1147 	AUDIT_ARG_PID((pid_t)id);	/* XXX - This may be wrong! */
1148 	AUDIT_ARG_VALUE(options);
1149 
1150 	q = td->td_proc;
1151 
1152 	if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) {
1153 		PROC_LOCK(q);
1154 		id = (id_t)q->p_pgid;
1155 		PROC_UNLOCK(q);
1156 		idtype = P_PGID;
1157 	}
1158 
1159 	/* If we don't know the option, just return. */
1160 	if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT |
1161 	    WEXITED | WTRAPPED | WLINUXCLONE)) != 0)
1162 		return (EINVAL);
1163 	if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) {
1164 		/*
1165 		 * We will be unable to find any matching processes,
1166 		 * because there are no known events to look for.
1167 		 * Prefer to return error instead of blocking
1168 		 * indefinitely.
1169 		 */
1170 		return (EINVAL);
1171 	}
1172 
1173 loop:
1174 	if (q->p_flag & P_STATCHILD) {
1175 		PROC_LOCK(q);
1176 		q->p_flag &= ~P_STATCHILD;
1177 		PROC_UNLOCK(q);
1178 	}
1179 	nfound = 0;
1180 	sx_xlock(&proctree_lock);
1181 	LIST_FOREACH(p, &q->p_children, p_sibling) {
1182 		ret = proc_to_reap(td, p, idtype, id, status, options,
1183 		    wrusage, siginfo);
1184 		if (ret == 0)
1185 			continue;
1186 		else if (ret == 1)
1187 			nfound++;
1188 		else
1189 			return (0);
1190 
1191 		PROC_LOCK(p);
1192 		PROC_SLOCK(p);
1193 
1194 		if ((options & WTRAPPED) != 0 &&
1195 		    (p->p_flag & P_TRACED) != 0 &&
1196 		    (p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) != 0 &&
1197 		    (p->p_suspcount == p->p_numthreads) &&
1198 		    ((p->p_flag & P_WAITED) == 0)) {
1199 			PROC_SUNLOCK(p);
1200 			if ((options & WNOWAIT) == 0)
1201 				p->p_flag |= P_WAITED;
1202 			sx_xunlock(&proctree_lock);
1203 			td->td_retval[0] = p->p_pid;
1204 
1205 			if (status != NULL)
1206 				*status = W_STOPCODE(p->p_xstat);
1207 			if (siginfo != NULL) {
1208 				siginfo->si_status = p->p_xstat;
1209 				siginfo->si_code = CLD_TRAPPED;
1210 			}
1211 			if ((options & WNOWAIT) == 0) {
1212 				PROC_LOCK(q);
1213 				sigqueue_take(p->p_ksi);
1214 				PROC_UNLOCK(q);
1215 			}
1216 
1217 			PROC_UNLOCK(p);
1218 			return (0);
1219 		}
1220 		if ((options & WUNTRACED) != 0 &&
1221 		    (p->p_flag & P_STOPPED_SIG) != 0 &&
1222 		    (p->p_suspcount == p->p_numthreads) &&
1223 		    ((p->p_flag & P_WAITED) == 0)) {
1224 			PROC_SUNLOCK(p);
1225 			if ((options & WNOWAIT) == 0)
1226 				p->p_flag |= P_WAITED;
1227 			sx_xunlock(&proctree_lock);
1228 			td->td_retval[0] = p->p_pid;
1229 
1230 			if (status != NULL)
1231 				*status = W_STOPCODE(p->p_xstat);
1232 			if (siginfo != NULL) {
1233 				siginfo->si_status = p->p_xstat;
1234 				siginfo->si_code = CLD_STOPPED;
1235 			}
1236 			if ((options & WNOWAIT) == 0) {
1237 				PROC_LOCK(q);
1238 				sigqueue_take(p->p_ksi);
1239 				PROC_UNLOCK(q);
1240 			}
1241 
1242 			PROC_UNLOCK(p);
1243 			return (0);
1244 		}
1245 		PROC_SUNLOCK(p);
1246 		if ((options & WCONTINUED) != 0 &&
1247 		    (p->p_flag & P_CONTINUED) != 0) {
1248 			sx_xunlock(&proctree_lock);
1249 			td->td_retval[0] = p->p_pid;
1250 			if ((options & WNOWAIT) == 0) {
1251 				p->p_flag &= ~P_CONTINUED;
1252 				PROC_LOCK(q);
1253 				sigqueue_take(p->p_ksi);
1254 				PROC_UNLOCK(q);
1255 			}
1256 			PROC_UNLOCK(p);
1257 
1258 			if (status != NULL)
1259 				*status = SIGCONT;
1260 			if (siginfo != NULL) {
1261 				siginfo->si_status = SIGCONT;
1262 				siginfo->si_code = CLD_CONTINUED;
1263 			}
1264 			return (0);
1265 		}
1266 		PROC_UNLOCK(p);
1267 	}
1268 
1269 	/*
1270 	 * Look in the orphans list too, to allow the parent to
1271 	 * collect it's child exit status even if child is being
1272 	 * debugged.
1273 	 *
1274 	 * Debugger detaches from the parent upon successful
1275 	 * switch-over from parent to child.  At this point due to
1276 	 * re-parenting the parent loses the child to debugger and a
1277 	 * wait4(2) call would report that it has no children to wait
1278 	 * for.  By maintaining a list of orphans we allow the parent
1279 	 * to successfully wait until the child becomes a zombie.
1280 	 */
1281 	LIST_FOREACH(p, &q->p_orphans, p_orphan) {
1282 		ret = proc_to_reap(td, p, idtype, id, status, options,
1283 		    wrusage, siginfo);
1284 		if (ret == 0)
1285 			continue;
1286 		else if (ret == 1)
1287 			nfound++;
1288 		else
1289 			return (0);
1290 	}
1291 	if (nfound == 0) {
1292 		sx_xunlock(&proctree_lock);
1293 		return (ECHILD);
1294 	}
1295 	if (options & WNOHANG) {
1296 		sx_xunlock(&proctree_lock);
1297 		td->td_retval[0] = 0;
1298 		return (0);
1299 	}
1300 	PROC_LOCK(q);
1301 	sx_xunlock(&proctree_lock);
1302 	if (q->p_flag & P_STATCHILD) {
1303 		q->p_flag &= ~P_STATCHILD;
1304 		error = 0;
1305 	} else
1306 		error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
1307 	PROC_UNLOCK(q);
1308 	if (error)
1309 		return (error);
1310 	goto loop;
1311 }
1312 
1313 /*
1314  * Make process 'parent' the new parent of process 'child'.
1315  * Must be called with an exclusive hold of proctree lock.
1316  */
1317 void
1318 proc_reparent(struct proc *child, struct proc *parent)
1319 {
1320 
1321 	sx_assert(&proctree_lock, SX_XLOCKED);
1322 	PROC_LOCK_ASSERT(child, MA_OWNED);
1323 	if (child->p_pptr == parent)
1324 		return;
1325 
1326 	PROC_LOCK(child->p_pptr);
1327 	sigqueue_take(child->p_ksi);
1328 	PROC_UNLOCK(child->p_pptr);
1329 	LIST_REMOVE(child, p_sibling);
1330 	LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1331 
1332 	clear_orphan(child);
1333 	if (child->p_flag & P_TRACED) {
1334 		if (LIST_EMPTY(&child->p_pptr->p_orphans)) {
1335 			child->p_treeflag |= P_TREE_FIRST_ORPHAN;
1336 			LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child,
1337 			    p_orphan);
1338 		} else {
1339 			LIST_INSERT_AFTER(LIST_FIRST(&child->p_pptr->p_orphans),
1340 			    child, p_orphan);
1341 		}
1342 		child->p_treeflag |= P_TREE_ORPHANED;
1343 	}
1344 
1345 	child->p_pptr = parent;
1346 }
1347