FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41
42 #include "opt_ddb.h"
43 #include "opt_ktrace.h"
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/sysproto.h>
48 #include <sys/capsicum.h>
49 #include <sys/eventhandler.h>
50 #include <sys/kernel.h>
51 #include <sys/ktr.h>
52 #include <sys/malloc.h>
53 #include <sys/lock.h>
54 #include <sys/mutex.h>
55 #include <sys/proc.h>
56 #include <sys/procdesc.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/sysctl.h>
70 #include <sys/syslog.h>
71 #include <sys/ptrace.h>
72 #include <sys/acct.h> /* for acct_process() function prototype */
73 #include <sys/filedesc.h>
74 #include <sys/sdt.h>
75 #include <sys/shm.h>
76 #include <sys/sem.h>
77 #include <sys/sysent.h>
78 #include <sys/timers.h>
79 #include <sys/umtxvar.h>
80 #ifdef KTRACE
81 #include <sys/ktrace.h>
82 #endif
83
84 #include <security/audit/audit.h>
85 #include <security/mac/mac_framework.h>
86
87 #include <vm/vm.h>
88 #include <vm/vm_extern.h>
89 #include <vm/vm_param.h>
90 #include <vm/pmap.h>
91 #include <vm/vm_map.h>
92 #include <vm/vm_page.h>
93 #include <vm/uma.h>
94
95 #ifdef KDTRACE_HOOKS
96 #include <sys/dtrace_bsd.h>
97 dtrace_execexit_func_t dtrace_fasttrap_exit;
98 #endif
99
100 SDT_PROVIDER_DECLARE(proc);
101 SDT_PROBE_DEFINE1(proc, , , exit, "int");
102
103 static int kern_kill_on_dbg_exit = 1;
104 SYSCTL_INT(_kern, OID_AUTO, kill_on_debugger_exit, CTLFLAG_RWTUN,
105 &kern_kill_on_dbg_exit, 0,
106 "Kill ptraced processes when debugger exits");
107
108 static bool kern_wait_dequeue_sigchld = 1;
109 SYSCTL_BOOL(_kern, OID_AUTO, wait_dequeue_sigchld, CTLFLAG_RWTUN,
110 &kern_wait_dequeue_sigchld, 0,
111 "Dequeue SIGCHLD on wait(2) for live process");
112
113 struct proc *
114 proc_realparent(struct proc *child)
115 {
116 struct proc *p, *parent;
117
118 sx_assert(&proctree_lock, SX_LOCKED);
119 if ((child->p_treeflag & P_TREE_ORPHANED) == 0)
120 return (child->p_pptr->p_pid == child->p_oppid ?
121 child->p_pptr : child->p_reaper);
122 for (p = child; (p->p_treeflag & P_TREE_FIRST_ORPHAN) == 0;) {
123 /* Cannot use LIST_PREV(), since the list head is not known. */
124 p = __containerof(p->p_orphan.le_prev, struct proc,
125 p_orphan.le_next);
126 KASSERT((p->p_treeflag & P_TREE_ORPHANED) != 0,
127 ("missing P_ORPHAN %p", p));
128 }
129 parent = __containerof(p->p_orphan.le_prev, struct proc,
130 p_orphans.lh_first);
131 return (parent);
132 }
133
134 void
135 reaper_abandon_children(struct proc *p, bool exiting)
136 {
137 struct proc *p1, *p2, *ptmp;
138
139 sx_assert(&proctree_lock, SX_XLOCKED);
140 KASSERT(p != initproc, ("reaper_abandon_children for initproc"));
141 if ((p->p_treeflag & P_TREE_REAPER) == 0)
142 return;
143 p1 = p->p_reaper;
144 LIST_FOREACH_SAFE(p2, &p->p_reaplist, p_reapsibling, ptmp) {
145 LIST_REMOVE(p2, p_reapsibling);
146 p2->p_reaper = p1;
147 p2->p_reapsubtree = p->p_reapsubtree;
148 LIST_INSERT_HEAD(&p1->p_reaplist, p2, p_reapsibling);
149 if (exiting && p2->p_pptr == p) {
150 PROC_LOCK(p2);
151 proc_reparent(p2, p1, true);
152 PROC_UNLOCK(p2);
153 }
154 }
155 KASSERT(LIST_EMPTY(&p->p_reaplist), ("p_reaplist not empty"));
156 p->p_treeflag &= ~P_TREE_REAPER;
157 }
158
159 static void
160 reaper_clear(struct proc *p)
161 {
162 struct proc *p1;
163 bool clear;
164
165 sx_assert(&proctree_lock, SX_LOCKED);
166 LIST_REMOVE(p, p_reapsibling);
167 if (p->p_reapsubtree == 1)
168 return;
169 clear = true;
170 LIST_FOREACH(p1, &p->p_reaper->p_reaplist, p_reapsibling) {
171 if (p1->p_reapsubtree == p->p_reapsubtree) {
172 clear = false;
173 break;
174 }
175 }
176 if (clear)
177 proc_id_clear(PROC_ID_REAP, p->p_reapsubtree);
178 }
179
180 void
181 proc_clear_orphan(struct proc *p)
182 {
183 struct proc *p1;
184
185 sx_assert(&proctree_lock, SA_XLOCKED);
186 if ((p->p_treeflag & P_TREE_ORPHANED) == 0)
187 return;
188 if ((p->p_treeflag & P_TREE_FIRST_ORPHAN) != 0) {
189 p1 = LIST_NEXT(p, p_orphan);
190 if (p1 != NULL)
191 p1->p_treeflag |= P_TREE_FIRST_ORPHAN;
192 p->p_treeflag &= ~P_TREE_FIRST_ORPHAN;
193 }
194 LIST_REMOVE(p, p_orphan);
195 p->p_treeflag &= ~P_TREE_ORPHANED;
196 }
197
198 void
199 exit_onexit(struct proc *p)
200 {
201 MPASS(p->p_numthreads == 1);
202 umtx_thread_exit(FIRST_THREAD_IN_PROC(p));
203 }
204
205 /*
206 * exit -- death of process.
207 */
208 void
209 sys_sys_exit(struct thread *td, struct sys_exit_args *uap)
210 {
211
212 exit1(td, uap->rval, 0);
213 /* NOTREACHED */
214 }
215
216 void
217 proc_set_p2_wexit(struct proc *p)
218 {
219 PROC_LOCK_ASSERT(p, MA_OWNED);
220 p->p_flag2 |= P2_WEXIT;
221 }
222
223 /*
224 * Exit: deallocate address space and other resources, change proc state to
225 * zombie, and unlink proc from allproc and parent's lists. Save exit status
226 * and rusage for wait(). Check for child processes and orphan them.
227 */
228 void
229 exit1(struct thread *td, int rval, int signo)
230 {
231 struct proc *p, *nq, *q, *t;
232 struct thread *tdt;
233 ksiginfo_t *ksi, *ksi1;
234 int signal_parent;
235
236 mtx_assert(&Giant, MA_NOTOWNED);
237 KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo));
238 TSPROCEXIT(td->td_proc->p_pid);
239
240 p = td->td_proc;
241 /*
242 * XXX in case we're rebooting we just let init die in order to
243 * work around an unsolved stack overflow seen very late during
244 * shutdown on sparc64 when the gmirror worker process exists.
245 * XXX what to do now that sparc64 is gone... remove if?
246 */
247 if (p == initproc && rebooting == 0) {
248 printf("init died (signal %d, exit %d)\n", signo, rval);
249 panic("Going nowhere without my init!");
250 }
251
252 /*
253 * Deref SU mp, since the thread does not return to userspace.
254 */
255 td_softdep_cleanup(td);
256
257 /*
258 * MUST abort all other threads before proceeding past here.
259 */
260 PROC_LOCK(p);
261 proc_set_p2_wexit(p);
262
263 /*
264 * First check if some other thread or external request got
265 * here before us. If so, act appropriately: exit or suspend.
266 * We must ensure that stop requests are handled before we set
267 * P_WEXIT.
268 */
269 thread_suspend_check(0);
270 while (p->p_flag & P_HADTHREADS) {
271 /*
272 * Kill off the other threads. This requires
273 * some co-operation from other parts of the kernel
274 * so it may not be instantaneous. With this state set
275 * any thread attempting to interruptibly
276 * sleep will return immediately with EINTR or EWOULDBLOCK
277 * which will hopefully force them to back out to userland
278 * freeing resources as they go. Any thread attempting
279 * to return to userland will thread_exit() from ast().
280 * thread_exit() will unsuspend us when the last of the
281 * other threads exits.
282 * If there is already a thread singler after resumption,
283 * calling thread_single() will fail; in that case, we just
284 * re-check all suspension request, the thread should
285 * either be suspended there or exit.
286 */
287 if (!thread_single(p, SINGLE_EXIT))
288 /*
289 * All other activity in this process is now
290 * stopped. Threading support has been turned
291 * off.
292 */
293 break;
294 /*
295 * Recheck for new stop or suspend requests which
296 * might appear while process lock was dropped in
297 * thread_single().
298 */
299 thread_suspend_check(0);
300 }
301 KASSERT(p->p_numthreads == 1,
302 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
303 racct_sub(p, RACCT_NTHR, 1);
304
305 /* Let event handler change exit status */
306 p->p_xexit = rval;
307 p->p_xsig = signo;
308
309 /*
310 * Ignore any pending request to stop due to a stop signal.
311 * Once P_WEXIT is set, future requests will be ignored as
312 * well.
313 */
314 p->p_flag &= ~P_STOPPED_SIG;
315 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped"));
316
317 /* Note that we are exiting. */
318 p->p_flag |= P_WEXIT;
319
320 /*
321 * Wait for any processes that have a hold on our vmspace to
322 * release their reference.
323 */
324 while (p->p_lock > 0)
325 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
326
327 PROC_UNLOCK(p);
328 /* Drain the limit callout while we don't have the proc locked */
329 callout_drain(&p->p_limco);
330
331 #ifdef AUDIT
332 /*
333 * The Sun BSM exit token contains two components: an exit status as
334 * passed to exit(), and a return value to indicate what sort of exit
335 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
336 * what the return value is.
337 */
338 AUDIT_ARG_EXIT(rval, 0);
339 AUDIT_SYSCALL_EXIT(0, td);
340 #endif
341
342 /* Are we a task leader with peers? */
343 if (p->p_peers != NULL && p == p->p_leader) {
344 mtx_lock(&ppeers_lock);
345 q = p->p_peers;
346 while (q != NULL) {
347 PROC_LOCK(q);
348 kern_psignal(q, SIGKILL);
349 PROC_UNLOCK(q);
350 q = q->p_peers;
351 }
352 while (p->p_peers != NULL)
353 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
354 mtx_unlock(&ppeers_lock);
355 }
356
357 itimers_exit(p);
358
359 /*
360 * Check if any loadable modules need anything done at process exit.
361 * E.g. SYSV IPC stuff.
362 * Event handler could change exit status.
363 * XXX what if one of these generates an error?
364 */
365 EVENTHANDLER_DIRECT_INVOKE(process_exit, p);
366
367 /*
368 * If parent is waiting for us to exit or exec,
369 * P_PPWAIT is set; we will wakeup the parent below.
370 */
371 PROC_LOCK(p);
372 stopprofclock(p);
373 p->p_ptevents = 0;
374
375 /*
376 * Stop the real interval timer. If the handler is currently
377 * executing, prevent it from rearming itself and let it finish.
378 */
379 if (timevalisset(&p->p_realtimer.it_value) &&
380 callout_stop(&p->p_itcallout) == 0) {
381 timevalclear(&p->p_realtimer.it_interval);
382 PROC_UNLOCK(p);
383 callout_drain(&p->p_itcallout);
384 } else {
385 PROC_UNLOCK(p);
386 }
387
388 if (p->p_sysent->sv_onexit != NULL)
389 p->p_sysent->sv_onexit(p);
390 seltdfini(td);
391
392 /*
393 * Reset any sigio structures pointing to us as a result of
394 * F_SETOWN with our pid. The P_WEXIT flag interlocks with fsetown().
395 */
396 funsetownlst(&p->p_sigiolst);
397
398 /*
399 * Close open files and release open-file table.
400 * This may block!
401 */
402 pdescfree(td);
403 fdescfree(td);
404
405 /*
406 * If this thread tickled GEOM, we need to wait for the giggling to
407 * stop before we return to userland
408 */
409 if (td->td_pflags & TDP_GEOM)
410 g_waitidle();
411
412 /*
413 * Remove ourself from our leader's peer list and wake our leader.
414 */
415 if (p->p_leader->p_peers != NULL) {
416 mtx_lock(&ppeers_lock);
417 if (p->p_leader->p_peers != NULL) {
418 q = p->p_leader;
419 while (q->p_peers != p)
420 q = q->p_peers;
421 q->p_peers = p->p_peers;
422 wakeup(p->p_leader);
423 }
424 mtx_unlock(&ppeers_lock);
425 }
426
427 exec_free_abi_mappings(p);
428 vmspace_exit(td);
429 (void)acct_process(td);
430
431 #ifdef KTRACE
432 ktrprocexit(td);
433 #endif
434 /*
435 * Release reference to text vnode etc
436 */
437 if (p->p_textvp != NULL) {
438 vrele(p->p_textvp);
439 p->p_textvp = NULL;
440 }
441 if (p->p_textdvp != NULL) {
442 vrele(p->p_textdvp);
443 p->p_textdvp = NULL;
444 }
445 if (p->p_binname != NULL) {
446 free(p->p_binname, M_PARGS);
447 p->p_binname = NULL;
448 }
449
450 /*
451 * Release our limits structure.
452 */
453 lim_free(p->p_limit);
454 p->p_limit = NULL;
455
456 tidhash_remove(td);
457
458 /*
459 * Call machine-dependent code to release any
460 * machine-dependent resources other than the address space.
461 * The address space is released by "vmspace_exitfree(p)" in
462 * vm_waitproc().
463 */
464 cpu_exit(td);
465
466 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
467
468 /*
469 * Remove from allproc. It still sits in the hash.
470 */
471 sx_xlock(&allproc_lock);
472 LIST_REMOVE(p, p_list);
473
474 #ifdef DDB
475 /*
476 * Used by ddb's 'ps' command to find this process via the
477 * pidhash.
478 */
479 p->p_list.le_prev = NULL;
480 #endif
481 sx_xunlock(&allproc_lock);
482
483 sx_xlock(&proctree_lock);
484 PROC_LOCK(p);
485 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE);
486 PROC_UNLOCK(p);
487
488 /*
489 * killjobc() might drop and re-acquire proctree_lock to
490 * revoke control tty if exiting process was a session leader.
491 */
492 killjobc();
493
494 /*
495 * Reparent all children processes:
496 * - traced ones to the original parent (or init if we are that parent)
497 * - the rest to init
498 */
499 q = LIST_FIRST(&p->p_children);
500 if (q != NULL) /* only need this if any child is S_ZOMB */
501 wakeup(q->p_reaper);
502 for (; q != NULL; q = nq) {
503 nq = LIST_NEXT(q, p_sibling);
504 ksi = ksiginfo_alloc(M_WAITOK);
505 PROC_LOCK(q);
506 q->p_sigparent = SIGCHLD;
507
508 if ((q->p_flag & P_TRACED) == 0) {
509 proc_reparent(q, q->p_reaper, true);
510 if (q->p_state == PRS_ZOMBIE) {
511 /*
512 * Inform reaper about the reparented
513 * zombie, since wait(2) has something
514 * new to report. Guarantee queueing
515 * of the SIGCHLD signal, similar to
516 * the _exit() behaviour, by providing
517 * our ksiginfo. Ksi is freed by the
518 * signal delivery.
519 */
520 if (q->p_ksi == NULL) {
521 ksi1 = NULL;
522 } else {
523 ksiginfo_copy(q->p_ksi, ksi);
524 ksi->ksi_flags |= KSI_INS;
525 ksi1 = ksi;
526 ksi = NULL;
527 }
528 PROC_LOCK(q->p_reaper);
529 pksignal(q->p_reaper, SIGCHLD, ksi1);
530 PROC_UNLOCK(q->p_reaper);
531 } else if (q->p_pdeathsig > 0) {
532 /*
533 * The child asked to received a signal
534 * when we exit.
535 */
536 kern_psignal(q, q->p_pdeathsig);
537 }
538 } else {
539 /*
540 * Traced processes are killed by default
541 * since their existence means someone is
542 * screwing up.
543 */
544 t = proc_realparent(q);
545 if (t == p) {
546 proc_reparent(q, q->p_reaper, true);
547 } else {
548 PROC_LOCK(t);
549 proc_reparent(q, t, true);
550 PROC_UNLOCK(t);
551 }
552 /*
553 * Since q was found on our children list, the
554 * proc_reparent() call moved q to the orphan
555 * list due to present P_TRACED flag. Clear
556 * orphan link for q now while q is locked.
557 */
558 proc_clear_orphan(q);
559 q->p_flag &= ~P_TRACED;
560 q->p_flag2 &= ~P2_PTRACE_FSTP;
561 q->p_ptevents = 0;
562 p->p_xthread = NULL;
563 FOREACH_THREAD_IN_PROC(q, tdt) {
564 tdt->td_dbgflags &= ~(TDB_SUSPEND | TDB_XSIG |
565 TDB_FSTP);
566 tdt->td_xsig = 0;
567 }
568 if (kern_kill_on_dbg_exit) {
569 q->p_flag &= ~P_STOPPED_TRACE;
570 kern_psignal(q, SIGKILL);
571 } else if ((q->p_flag & (P_STOPPED_TRACE |
572 P_STOPPED_SIG)) != 0) {
573 sigqueue_delete_proc(q, SIGTRAP);
574 ptrace_unsuspend(q);
575 }
576 }
577 PROC_UNLOCK(q);
578 if (ksi != NULL)
579 ksiginfo_free(ksi);
580 }
581
582 /*
583 * Also get rid of our orphans.
584 */
585 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) {
586 PROC_LOCK(q);
587 KASSERT(q->p_oppid == p->p_pid,
588 ("orphan %p of %p has unexpected oppid %d", q, p,
589 q->p_oppid));
590 q->p_oppid = q->p_reaper->p_pid;
591
592 /*
593 * If we are the real parent of this process
594 * but it has been reparented to a debugger, then
595 * check if it asked for a signal when we exit.
596 */
597 if (q->p_pdeathsig > 0)
598 kern_psignal(q, q->p_pdeathsig);
599 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid,
600 q->p_pid);
601 proc_clear_orphan(q);
602 PROC_UNLOCK(q);
603 }
604
605 #ifdef KDTRACE_HOOKS
606 if (SDT_PROBES_ENABLED()) {
607 int reason = CLD_EXITED;
608 if (WCOREDUMP(signo))
609 reason = CLD_DUMPED;
610 else if (WIFSIGNALED(signo))
611 reason = CLD_KILLED;
612 SDT_PROBE1(proc, , , exit, reason);
613 }
614 #endif
615
616 /* Save exit status. */
617 PROC_LOCK(p);
618 p->p_xthread = td;
619
620 if (p->p_sysent->sv_ontdexit != NULL)
621 p->p_sysent->sv_ontdexit(td);
622
623 #ifdef KDTRACE_HOOKS
624 /*
625 * Tell the DTrace fasttrap provider about the exit if it
626 * has declared an interest.
627 */
628 if (dtrace_fasttrap_exit)
629 dtrace_fasttrap_exit(p);
630 #endif
631
632 /*
633 * Notify interested parties of our demise.
634 */
635 KNOTE_LOCKED(p->p_klist, NOTE_EXIT);
636
637 /*
638 * If this is a process with a descriptor, we may not need to deliver
639 * a signal to the parent. proctree_lock is held over
640 * procdesc_exit() to serialize concurrent calls to close() and
641 * exit().
642 */
643 signal_parent = 0;
644 if (p->p_procdesc == NULL || procdesc_exit(p)) {
645 /*
646 * Notify parent that we're gone. If parent has the
647 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN,
648 * notify process 1 instead (and hope it will handle this
649 * situation).
650 */
651 PROC_LOCK(p->p_pptr);
652 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
653 if (p->p_pptr->p_sigacts->ps_flag &
654 (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
655 struct proc *pp;
656
657 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
658 pp = p->p_pptr;
659 PROC_UNLOCK(pp);
660 proc_reparent(p, p->p_reaper, true);
661 p->p_sigparent = SIGCHLD;
662 PROC_LOCK(p->p_pptr);
663
664 /*
665 * Notify parent, so in case he was wait(2)ing or
666 * executing waitpid(2) with our pid, he will
667 * continue.
668 */
669 wakeup(pp);
670 } else
671 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
672
673 if (p->p_pptr == p->p_reaper || p->p_pptr == initproc) {
674 signal_parent = 1;
675 } else if (p->p_sigparent != 0) {
676 if (p->p_sigparent == SIGCHLD) {
677 signal_parent = 1;
678 } else { /* LINUX thread */
679 signal_parent = 2;
680 }
681 }
682 } else
683 PROC_LOCK(p->p_pptr);
684 sx_xunlock(&proctree_lock);
685
686 if (signal_parent == 1) {
687 childproc_exited(p);
688 } else if (signal_parent == 2) {
689 kern_psignal(p->p_pptr, p->p_sigparent);
690 }
691
692 /* Tell the prison that we are gone. */
693 prison_proc_free(p->p_ucred->cr_prison);
694
695 /*
696 * The state PRS_ZOMBIE prevents other proesses from sending
697 * signal to the process, to avoid memory leak, we free memory
698 * for signal queue at the time when the state is set.
699 */
700 sigqueue_flush(&p->p_sigqueue);
701 sigqueue_flush(&td->td_sigqueue);
702
703 /*
704 * We have to wait until after acquiring all locks before
705 * changing p_state. We need to avoid all possible context
706 * switches (including ones from blocking on a mutex) while
707 * marked as a zombie. We also have to set the zombie state
708 * before we release the parent process' proc lock to avoid
709 * a lost wakeup. So, we first call wakeup, then we grab the
710 * sched lock, update the state, and release the parent process'
711 * proc lock.
712 */
713 wakeup(p->p_pptr);
714 cv_broadcast(&p->p_pwait);
715 sched_exit(p->p_pptr, td);
716 PROC_SLOCK(p);
717 p->p_state = PRS_ZOMBIE;
718 PROC_UNLOCK(p->p_pptr);
719
720 /*
721 * Save our children's rusage information in our exit rusage.
722 */
723 PROC_STATLOCK(p);
724 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
725 PROC_STATUNLOCK(p);
726
727 /*
728 * Make sure the scheduler takes this thread out of its tables etc.
729 * This will also release this thread's reference to the ucred.
730 * Other thread parts to release include pcb bits and such.
731 */
732 thread_exit();
733 }
734
735 #ifndef _SYS_SYSPROTO_H_
736 struct abort2_args {
737 char *why;
738 int nargs;
739 void **args;
740 };
741 #endif
742
743 int
744 sys_abort2(struct thread *td, struct abort2_args *uap)
745 {
746 struct proc *p = td->td_proc;
747 struct sbuf *sb;
748 void *uargs[16];
749 int error, i, sig;
750
751 /*
752 * Do it right now so we can log either proper call of abort2(), or
753 * note, that invalid argument was passed. 512 is big enough to
754 * handle 16 arguments' descriptions with additional comments.
755 */
756 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
757 sbuf_clear(sb);
758 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
759 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
760 /*
761 * Since we can't return from abort2(), send SIGKILL in cases, where
762 * abort2() was called improperly
763 */
764 sig = SIGKILL;
765 /* Prevent from DoSes from user-space. */
766 if (uap->nargs < 0 || uap->nargs > 16)
767 goto out;
768 if (uap->nargs > 0) {
769 if (uap->args == NULL)
770 goto out;
771 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
772 if (error != 0)
773 goto out;
774 }
775 /*
776 * Limit size of 'reason' string to 128. Will fit even when
777 * maximal number of arguments was chosen to be logged.
778 */
779 if (uap->why != NULL) {
780 error = sbuf_copyin(sb, uap->why, 128);
781 if (error < 0)
782 goto out;
783 } else {
784 sbuf_printf(sb, "(null)");
785 }
786 if (uap->nargs > 0) {
787 sbuf_printf(sb, "(");
788 for (i = 0;i < uap->nargs; i++)
789 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
790 sbuf_printf(sb, ")");
791 }
792 /*
793 * Final stage: arguments were proper, string has been
794 * successfully copied from userspace, and copying pointers
795 * from user-space succeed.
796 */
797 sig = SIGABRT;
798 out:
799 if (sig == SIGKILL) {
800 sbuf_trim(sb);
801 sbuf_printf(sb, " (Reason text inaccessible)");
802 }
803 sbuf_cat(sb, "\n");
804 sbuf_finish(sb);
805 log(LOG_INFO, "%s", sbuf_data(sb));
806 sbuf_delete(sb);
807 exit1(td, 0, sig);
808 return (0);
809 }
810
811 #ifdef COMPAT_43
812 /*
813 * The dirty work is handled by kern_wait().
814 */
815 int
816 owait(struct thread *td, struct owait_args *uap __unused)
817 {
818 int error, status;
819
820 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
821 if (error == 0)
822 td->td_retval[1] = status;
823 return (error);
824 }
825 #endif /* COMPAT_43 */
826
827 /*
828 * The dirty work is handled by kern_wait().
829 */
830 int
831 sys_wait4(struct thread *td, struct wait4_args *uap)
832 {
833 struct rusage ru, *rup;
834 int error, status;
835
836 if (uap->rusage != NULL)
837 rup = &ru;
838 else
839 rup = NULL;
840 error = kern_wait(td, uap->pid, &status, uap->options, rup);
841 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0)
842 error = copyout(&status, uap->status, sizeof(status));
843 if (uap->rusage != NULL && error == 0 && td->td_retval[0] != 0)
844 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
845 return (error);
846 }
847
848 int
849 sys_wait6(struct thread *td, struct wait6_args *uap)
850 {
851 struct __wrusage wru, *wrup;
852 siginfo_t si, *sip;
853 idtype_t idtype;
854 id_t id;
855 int error, status;
856
857 idtype = uap->idtype;
858 id = uap->id;
859
860 if (uap->wrusage != NULL)
861 wrup = &wru;
862 else
863 wrup = NULL;
864
865 if (uap->info != NULL) {
866 sip = &si;
867 bzero(sip, sizeof(*sip));
868 } else
869 sip = NULL;
870
871 /*
872 * We expect all callers of wait6() to know about WEXITED and
873 * WTRAPPED.
874 */
875 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip);
876
877 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0)
878 error = copyout(&status, uap->status, sizeof(status));
879 if (uap->wrusage != NULL && error == 0 && td->td_retval[0] != 0)
880 error = copyout(&wru, uap->wrusage, sizeof(wru));
881 if (uap->info != NULL && error == 0)
882 error = copyout(&si, uap->info, sizeof(si));
883 return (error);
884 }
885
886 /*
887 * Reap the remains of a zombie process and optionally return status and
888 * rusage. Asserts and will release both the proctree_lock and the process
889 * lock as part of its work.
890 */
891 void
892 proc_reap(struct thread *td, struct proc *p, int *status, int options)
893 {
894 struct proc *q, *t;
895
896 sx_assert(&proctree_lock, SA_XLOCKED);
897 PROC_LOCK_ASSERT(p, MA_OWNED);
898 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
899
900 mtx_spin_wait_unlocked(&p->p_slock);
901
902 q = td->td_proc;
903
904 if (status)
905 *status = KW_EXITCODE(p->p_xexit, p->p_xsig);
906 if (options & WNOWAIT) {
907 /*
908 * Only poll, returning the status. Caller does not wish to
909 * release the proc struct just yet.
910 */
911 PROC_UNLOCK(p);
912 sx_xunlock(&proctree_lock);
913 return;
914 }
915
916 PROC_LOCK(q);
917 sigqueue_take(p->p_ksi);
918 PROC_UNLOCK(q);
919
920 /*
921 * If we got the child via a ptrace 'attach', we need to give it back
922 * to the old parent.
923 */
924 if (p->p_oppid != p->p_pptr->p_pid) {
925 PROC_UNLOCK(p);
926 t = proc_realparent(p);
927 PROC_LOCK(t);
928 PROC_LOCK(p);
929 CTR2(KTR_PTRACE,
930 "wait: traced child %d moved back to parent %d", p->p_pid,
931 t->p_pid);
932 proc_reparent(p, t, false);
933 PROC_UNLOCK(p);
934 pksignal(t, SIGCHLD, p->p_ksi);
935 wakeup(t);
936 cv_broadcast(&p->p_pwait);
937 PROC_UNLOCK(t);
938 sx_xunlock(&proctree_lock);
939 return;
940 }
941 PROC_UNLOCK(p);
942
943 /*
944 * Remove other references to this process to ensure we have an
945 * exclusive reference.
946 */
947 sx_xlock(PIDHASHLOCK(p->p_pid));
948 LIST_REMOVE(p, p_hash);
949 sx_xunlock(PIDHASHLOCK(p->p_pid));
950 LIST_REMOVE(p, p_sibling);
951 reaper_abandon_children(p, true);
952 reaper_clear(p);
953 PROC_LOCK(p);
954 proc_clear_orphan(p);
955 PROC_UNLOCK(p);
956 leavepgrp(p);
957 if (p->p_procdesc != NULL)
958 procdesc_reap(p);
959 sx_xunlock(&proctree_lock);
960
961 proc_id_clear(PROC_ID_PID, p->p_pid);
962
963 PROC_LOCK(p);
964 knlist_detach(p->p_klist);
965 p->p_klist = NULL;
966 PROC_UNLOCK(p);
967
968 /*
969 * Removal from allproc list and process group list paired with
970 * PROC_LOCK which was executed during that time should guarantee
971 * nothing can reach this process anymore. As such further locking
972 * is unnecessary.
973 */
974 p->p_xexit = p->p_xsig = 0; /* XXX: why? */
975
976 PROC_LOCK(q);
977 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
978 PROC_UNLOCK(q);
979
980 /*
981 * Decrement the count of procs running with this uid.
982 */
983 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
984
985 /*
986 * Destroy resource accounting information associated with the process.
987 */
988 #ifdef RACCT
989 if (racct_enable) {
990 PROC_LOCK(p);
991 racct_sub(p, RACCT_NPROC, 1);
992 PROC_UNLOCK(p);
993 }
994 #endif
995 racct_proc_exit(p);
996
997 /*
998 * Free credentials, arguments, and sigacts.
999 */
1000 proc_unset_cred(p);
1001 pargs_drop(p->p_args);
1002 p->p_args = NULL;
1003 sigacts_free(p->p_sigacts);
1004 p->p_sigacts = NULL;
1005
1006 /*
1007 * Do any thread-system specific cleanups.
1008 */
1009 thread_wait(p);
1010
1011 /*
1012 * Give vm and machine-dependent layer a chance to free anything that
1013 * cpu_exit couldn't release while still running in process context.
1014 */
1015 vm_waitproc(p);
1016 #ifdef MAC
1017 mac_proc_destroy(p);
1018 #endif
1019
1020 KASSERT(FIRST_THREAD_IN_PROC(p),
1021 ("proc_reap: no residual thread!"));
1022 uma_zfree(proc_zone, p);
1023 atomic_add_int(&nprocs, -1);
1024 }
1025
1026 static int
1027 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
1028 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo,
1029 int check_only)
1030 {
1031 struct rusage *rup;
1032
1033 sx_assert(&proctree_lock, SA_XLOCKED);
1034
1035 PROC_LOCK(p);
1036
1037 switch (idtype) {
1038 case P_ALL:
1039 if (p->p_procdesc == NULL ||
1040 (p->p_pptr == td->td_proc &&
1041 (p->p_flag & P_TRACED) != 0)) {
1042 break;
1043 }
1044
1045 PROC_UNLOCK(p);
1046 return (0);
1047 case P_PID:
1048 if (p->p_pid != (pid_t)id) {
1049 PROC_UNLOCK(p);
1050 return (0);
1051 }
1052 break;
1053 case P_PGID:
1054 if (p->p_pgid != (pid_t)id) {
1055 PROC_UNLOCK(p);
1056 return (0);
1057 }
1058 break;
1059 case P_SID:
1060 if (p->p_session->s_sid != (pid_t)id) {
1061 PROC_UNLOCK(p);
1062 return (0);
1063 }
1064 break;
1065 case P_UID:
1066 if (p->p_ucred->cr_uid != (uid_t)id) {
1067 PROC_UNLOCK(p);
1068 return (0);
1069 }
1070 break;
1071 case P_GID:
1072 if (p->p_ucred->cr_gid != (gid_t)id) {
1073 PROC_UNLOCK(p);
1074 return (0);
1075 }
1076 break;
1077 case P_JAILID:
1078 if (p->p_ucred->cr_prison->pr_id != (int)id) {
1079 PROC_UNLOCK(p);
1080 return (0);
1081 }
1082 break;
1083 /*
1084 * It seems that the thread structures get zeroed out
1085 * at process exit. This makes it impossible to
1086 * support P_SETID, P_CID or P_CPUID.
1087 */
1088 default:
1089 PROC_UNLOCK(p);
1090 return (0);
1091 }
1092
1093 if (p_canwait(td, p)) {
1094 PROC_UNLOCK(p);
1095 return (0);
1096 }
1097
1098 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) {
1099 PROC_UNLOCK(p);
1100 return (0);
1101 }
1102
1103 /*
1104 * This special case handles a kthread spawned by linux_clone
1105 * (see linux_misc.c). The linux_wait4 and linux_waitpid
1106 * functions need to be able to distinguish between waiting
1107 * on a process and waiting on a thread. It is a thread if
1108 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
1109 * signifies we want to wait for threads and not processes.
1110 */
1111 if ((p->p_sigparent != SIGCHLD) ^
1112 ((options & WLINUXCLONE) != 0)) {
1113 PROC_UNLOCK(p);
1114 return (0);
1115 }
1116
1117 if (siginfo != NULL) {
1118 bzero(siginfo, sizeof(*siginfo));
1119 siginfo->si_errno = 0;
1120
1121 /*
1122 * SUSv4 requires that the si_signo value is always
1123 * SIGCHLD. Obey it despite the rfork(2) interface
1124 * allows to request other signal for child exit
1125 * notification.
1126 */
1127 siginfo->si_signo = SIGCHLD;
1128
1129 /*
1130 * This is still a rough estimate. We will fix the
1131 * cases TRAPPED, STOPPED, and CONTINUED later.
1132 */
1133 if (WCOREDUMP(p->p_xsig)) {
1134 siginfo->si_code = CLD_DUMPED;
1135 siginfo->si_status = WTERMSIG(p->p_xsig);
1136 } else if (WIFSIGNALED(p->p_xsig)) {
1137 siginfo->si_code = CLD_KILLED;
1138 siginfo->si_status = WTERMSIG(p->p_xsig);
1139 } else {
1140 siginfo->si_code = CLD_EXITED;
1141 siginfo->si_status = p->p_xexit;
1142 }
1143
1144 siginfo->si_pid = p->p_pid;
1145 siginfo->si_uid = p->p_ucred->cr_uid;
1146
1147 /*
1148 * The si_addr field would be useful additional
1149 * detail, but apparently the PC value may be lost
1150 * when we reach this point. bzero() above sets
1151 * siginfo->si_addr to NULL.
1152 */
1153 }
1154
1155 /*
1156 * There should be no reason to limit resources usage info to
1157 * exited processes only. A snapshot about any resources used
1158 * by a stopped process may be exactly what is needed.
1159 */
1160 if (wrusage != NULL) {
1161 rup = &wrusage->wru_self;
1162 *rup = p->p_ru;
1163 PROC_STATLOCK(p);
1164 calcru(p, &rup->ru_utime, &rup->ru_stime);
1165 PROC_STATUNLOCK(p);
1166
1167 rup = &wrusage->wru_children;
1168 *rup = p->p_stats->p_cru;
1169 calccru(p, &rup->ru_utime, &rup->ru_stime);
1170 }
1171
1172 if (p->p_state == PRS_ZOMBIE && !check_only) {
1173 proc_reap(td, p, status, options);
1174 return (-1);
1175 }
1176 return (1);
1177 }
1178
1179 int
1180 kern_wait(struct thread *td, pid_t pid, int *status, int options,
1181 struct rusage *rusage)
1182 {
1183 struct __wrusage wru, *wrup;
1184 idtype_t idtype;
1185 id_t id;
1186 int ret;
1187
1188 /*
1189 * Translate the special pid values into the (idtype, pid)
1190 * pair for kern_wait6. The WAIT_MYPGRP case is handled by
1191 * kern_wait6() on its own.
1192 */
1193 if (pid == WAIT_ANY) {
1194 idtype = P_ALL;
1195 id = 0;
1196 } else if (pid < 0) {
1197 idtype = P_PGID;
1198 id = (id_t)-pid;
1199 } else {
1200 idtype = P_PID;
1201 id = (id_t)pid;
1202 }
1203
1204 if (rusage != NULL)
1205 wrup = &wru;
1206 else
1207 wrup = NULL;
1208
1209 /*
1210 * For backward compatibility we implicitly add flags WEXITED
1211 * and WTRAPPED here.
1212 */
1213 options |= WEXITED | WTRAPPED;
1214 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL);
1215 if (rusage != NULL)
1216 *rusage = wru.wru_self;
1217 return (ret);
1218 }
1219
1220 static void
1221 report_alive_proc(struct thread *td, struct proc *p, siginfo_t *siginfo,
1222 int *status, int options, int si_code)
1223 {
1224 bool cont;
1225
1226 PROC_LOCK_ASSERT(p, MA_OWNED);
1227 sx_assert(&proctree_lock, SA_XLOCKED);
1228 MPASS(si_code == CLD_TRAPPED || si_code == CLD_STOPPED ||
1229 si_code == CLD_CONTINUED);
1230
1231 cont = si_code == CLD_CONTINUED;
1232 if ((options & WNOWAIT) == 0) {
1233 if (cont)
1234 p->p_flag &= ~P_CONTINUED;
1235 else
1236 p->p_flag |= P_WAITED;
1237 if (kern_wait_dequeue_sigchld &&
1238 (td->td_proc->p_sysent->sv_flags & SV_SIG_WAITNDQ) == 0) {
1239 PROC_LOCK(td->td_proc);
1240 sigqueue_take(p->p_ksi);
1241 PROC_UNLOCK(td->td_proc);
1242 }
1243 }
1244 sx_xunlock(&proctree_lock);
1245 if (siginfo != NULL) {
1246 siginfo->si_code = si_code;
1247 siginfo->si_status = cont ? SIGCONT : p->p_xsig;
1248 }
1249 if (status != NULL)
1250 *status = cont ? SIGCONT : W_STOPCODE(p->p_xsig);
1251 PROC_UNLOCK(p);
1252 td->td_retval[0] = p->p_pid;
1253 }
1254
1255 int
1256 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status,
1257 int options, struct __wrusage *wrusage, siginfo_t *siginfo)
1258 {
1259 struct proc *p, *q;
1260 pid_t pid;
1261 int error, nfound, ret;
1262 bool report;
1263
1264 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */
1265 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */
1266 AUDIT_ARG_VALUE(options);
1267
1268 q = td->td_proc;
1269
1270 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) {
1271 PROC_LOCK(q);
1272 id = (id_t)q->p_pgid;
1273 PROC_UNLOCK(q);
1274 idtype = P_PGID;
1275 }
1276
1277 /* If we don't know the option, just return. */
1278 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT |
1279 WEXITED | WTRAPPED | WLINUXCLONE)) != 0)
1280 return (EINVAL);
1281 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) {
1282 /*
1283 * We will be unable to find any matching processes,
1284 * because there are no known events to look for.
1285 * Prefer to return error instead of blocking
1286 * indefinitely.
1287 */
1288 return (EINVAL);
1289 }
1290
1291 loop:
1292 if (q->p_flag & P_STATCHILD) {
1293 PROC_LOCK(q);
1294 q->p_flag &= ~P_STATCHILD;
1295 PROC_UNLOCK(q);
1296 }
1297 sx_xlock(&proctree_lock);
1298 loop_locked:
1299 nfound = 0;
1300 LIST_FOREACH(p, &q->p_children, p_sibling) {
1301 pid = p->p_pid;
1302 ret = proc_to_reap(td, p, idtype, id, status, options,
1303 wrusage, siginfo, 0);
1304 if (ret == 0)
1305 continue;
1306 else if (ret != 1) {
1307 td->td_retval[0] = pid;
1308 return (0);
1309 }
1310
1311 nfound++;
1312 PROC_LOCK_ASSERT(p, MA_OWNED);
1313
1314 if ((options & WTRAPPED) != 0 &&
1315 (p->p_flag & P_TRACED) != 0) {
1316 PROC_SLOCK(p);
1317 report =
1318 ((p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) &&
1319 p->p_suspcount == p->p_numthreads &&
1320 (p->p_flag & P_WAITED) == 0);
1321 PROC_SUNLOCK(p);
1322 if (report) {
1323 CTR4(KTR_PTRACE,
1324 "wait: returning trapped pid %d status %#x "
1325 "(xstat %d) xthread %d",
1326 p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig,
1327 p->p_xthread != NULL ?
1328 p->p_xthread->td_tid : -1);
1329 report_alive_proc(td, p, siginfo, status,
1330 options, CLD_TRAPPED);
1331 return (0);
1332 }
1333 }
1334 if ((options & WUNTRACED) != 0 &&
1335 (p->p_flag & P_STOPPED_SIG) != 0) {
1336 PROC_SLOCK(p);
1337 report = (p->p_suspcount == p->p_numthreads &&
1338 ((p->p_flag & P_WAITED) == 0));
1339 PROC_SUNLOCK(p);
1340 if (report) {
1341 report_alive_proc(td, p, siginfo, status,
1342 options, CLD_STOPPED);
1343 return (0);
1344 }
1345 }
1346 if ((options & WCONTINUED) != 0 &&
1347 (p->p_flag & P_CONTINUED) != 0) {
1348 report_alive_proc(td, p, siginfo, status, options,
1349 CLD_CONTINUED);
1350 return (0);
1351 }
1352 PROC_UNLOCK(p);
1353 }
1354
1355 /*
1356 * Look in the orphans list too, to allow the parent to
1357 * collect it's child exit status even if child is being
1358 * debugged.
1359 *
1360 * Debugger detaches from the parent upon successful
1361 * switch-over from parent to child. At this point due to
1362 * re-parenting the parent loses the child to debugger and a
1363 * wait4(2) call would report that it has no children to wait
1364 * for. By maintaining a list of orphans we allow the parent
1365 * to successfully wait until the child becomes a zombie.
1366 */
1367 if (nfound == 0) {
1368 LIST_FOREACH(p, &q->p_orphans, p_orphan) {
1369 ret = proc_to_reap(td, p, idtype, id, NULL, options,
1370 NULL, NULL, 1);
1371 if (ret != 0) {
1372 KASSERT(ret != -1, ("reaped an orphan (pid %d)",
1373 (int)td->td_retval[0]));
1374 PROC_UNLOCK(p);
1375 nfound++;
1376 break;
1377 }
1378 }
1379 }
1380 if (nfound == 0) {
1381 sx_xunlock(&proctree_lock);
1382 return (ECHILD);
1383 }
1384 if (options & WNOHANG) {
1385 sx_xunlock(&proctree_lock);
1386 td->td_retval[0] = 0;
1387 return (0);
1388 }
1389 PROC_LOCK(q);
1390 if (q->p_flag & P_STATCHILD) {
1391 q->p_flag &= ~P_STATCHILD;
1392 PROC_UNLOCK(q);
1393 goto loop_locked;
1394 }
1395 sx_xunlock(&proctree_lock);
1396 error = msleep(q, &q->p_mtx, PWAIT | PCATCH | PDROP, "wait", 0);
1397 if (error)
1398 return (error);
1399 goto loop;
1400 }
1401
1402 void
1403 proc_add_orphan(struct proc *child, struct proc *parent)
1404 {
1405
1406 sx_assert(&proctree_lock, SX_XLOCKED);
1407 KASSERT((child->p_flag & P_TRACED) != 0,
1408 ("proc_add_orphan: not traced"));
1409
1410 if (LIST_EMPTY(&parent->p_orphans)) {
1411 child->p_treeflag |= P_TREE_FIRST_ORPHAN;
1412 LIST_INSERT_HEAD(&parent->p_orphans, child, p_orphan);
1413 } else {
1414 LIST_INSERT_AFTER(LIST_FIRST(&parent->p_orphans),
1415 child, p_orphan);
1416 }
1417 child->p_treeflag |= P_TREE_ORPHANED;
1418 }
1419
1420 /*
1421 * Make process 'parent' the new parent of process 'child'.
1422 * Must be called with an exclusive hold of proctree lock.
1423 */
1424 void
1425 proc_reparent(struct proc *child, struct proc *parent, bool set_oppid)
1426 {
1427
1428 sx_assert(&proctree_lock, SX_XLOCKED);
1429 PROC_LOCK_ASSERT(child, MA_OWNED);
1430 if (child->p_pptr == parent)
1431 return;
1432
1433 PROC_LOCK(child->p_pptr);
1434 sigqueue_take(child->p_ksi);
1435 PROC_UNLOCK(child->p_pptr);
1436 LIST_REMOVE(child, p_sibling);
1437 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1438
1439 proc_clear_orphan(child);
1440 if ((child->p_flag & P_TRACED) != 0) {
1441 proc_add_orphan(child, child->p_pptr);
1442 }
1443
1444 child->p_pptr = parent;
1445 if (set_oppid)
1446 child->p_oppid = parent->p_pid;
1447 }
Cache object: a871b5bedb51fd477653f29698a5e4d0
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