FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
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: releng/8.2/sys/kern/kern_exit.c 199583 2009-11-20 15:27:52Z jhb $");
39
40 #include "opt_compat.h"
41 #include "opt_kdtrace.h"
42 #include "opt_ktrace.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/sysproto.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/pioctl.h>
54 #include <sys/jail.h>
55 #include <sys/tty.h>
56 #include <sys/wait.h>
57 #include <sys/vmmeter.h>
58 #include <sys/vnode.h>
59 #include <sys/resourcevar.h>
60 #include <sys/sbuf.h>
61 #include <sys/signalvar.h>
62 #include <sys/sched.h>
63 #include <sys/sx.h>
64 #include <sys/syscallsubr.h>
65 #include <sys/syslog.h>
66 #include <sys/ptrace.h>
67 #include <sys/acct.h> /* for acct_process() function prototype */
68 #include <sys/filedesc.h>
69 #include <sys/sdt.h>
70 #include <sys/shm.h>
71 #include <sys/sem.h>
72 #ifdef KTRACE
73 #include <sys/ktrace.h>
74 #endif
75
76 #include <security/audit/audit.h>
77 #include <security/mac/mac_framework.h>
78
79 #include <vm/vm.h>
80 #include <vm/vm_extern.h>
81 #include <vm/vm_param.h>
82 #include <vm/pmap.h>
83 #include <vm/vm_map.h>
84 #include <vm/vm_page.h>
85 #include <vm/uma.h>
86
87 #ifdef KDTRACE_HOOKS
88 #include <sys/dtrace_bsd.h>
89 dtrace_execexit_func_t dtrace_fasttrap_exit;
90 #endif
91
92 SDT_PROVIDER_DECLARE(proc);
93 SDT_PROBE_DEFINE(proc, kernel, , exit);
94 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int");
95
96 /* Required to be non-static for SysVR4 emulator */
97 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
98
99 /* Hook for NFS teardown procedure. */
100 void (*nlminfo_release_p)(struct proc *p);
101
102 /*
103 * exit -- death of process.
104 */
105 void
106 sys_exit(struct thread *td, struct sys_exit_args *uap)
107 {
108
109 exit1(td, W_EXITCODE(uap->rval, 0));
110 /* NOTREACHED */
111 }
112
113 /*
114 * Exit: deallocate address space and other resources, change proc state to
115 * zombie, and unlink proc from allproc and parent's lists. Save exit status
116 * and rusage for wait(). Check for child processes and orphan them.
117 */
118 void
119 exit1(struct thread *td, int rv)
120 {
121 struct proc *p, *nq, *q;
122 struct vnode *vtmp;
123 struct vnode *ttyvp = NULL;
124 #ifdef KTRACE
125 struct vnode *tracevp;
126 struct ucred *tracecred;
127 #endif
128 struct plimit *plim;
129 int locked;
130
131 mtx_assert(&Giant, MA_NOTOWNED);
132
133 p = td->td_proc;
134 /*
135 * XXX in case we're rebooting we just let init die in order to
136 * work around an unsolved stack overflow seen very late during
137 * shutdown on sparc64 when the gmirror worker process exists.
138 */
139 if (p == initproc && rebooting == 0) {
140 printf("init died (signal %d, exit %d)\n",
141 WTERMSIG(rv), WEXITSTATUS(rv));
142 panic("Going nowhere without my init!");
143 }
144
145 /*
146 * MUST abort all other threads before proceeding past here.
147 */
148 PROC_LOCK(p);
149 while (p->p_flag & P_HADTHREADS) {
150 /*
151 * First check if some other thread got here before us..
152 * if so, act apropriatly, (exit or suspend);
153 */
154 thread_suspend_check(0);
155
156 /*
157 * Kill off the other threads. This requires
158 * some co-operation from other parts of the kernel
159 * so it may not be instantaneous. With this state set
160 * any thread entering the kernel from userspace will
161 * thread_exit() in trap(). Any thread attempting to
162 * sleep will return immediately with EINTR or EWOULDBLOCK
163 * which will hopefully force them to back out to userland
164 * freeing resources as they go. Any thread attempting
165 * to return to userland will thread_exit() from userret().
166 * thread_exit() will unsuspend us when the last of the
167 * other threads exits.
168 * If there is already a thread singler after resumption,
169 * calling thread_single will fail; in that case, we just
170 * re-check all suspension request, the thread should
171 * either be suspended there or exit.
172 */
173 if (! thread_single(SINGLE_EXIT))
174 break;
175
176 /*
177 * All other activity in this process is now stopped.
178 * Threading support has been turned off.
179 */
180 }
181 KASSERT(p->p_numthreads == 1,
182 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
183 /*
184 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
185 * on our vmspace, so we should block below until they have
186 * released their reference to us. Note that if they have
187 * requested S_EXIT stops we will block here until they ack
188 * via PIOCCONT.
189 */
190 _STOPEVENT(p, S_EXIT, rv);
191
192 /*
193 * Note that we are exiting and do another wakeup of anyone in
194 * PIOCWAIT in case they aren't listening for S_EXIT stops or
195 * decided to wait again after we told them we are exiting.
196 */
197 p->p_flag |= P_WEXIT;
198 wakeup(&p->p_stype);
199
200 /*
201 * Wait for any processes that have a hold on our vmspace to
202 * release their reference.
203 */
204 while (p->p_lock > 0)
205 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
206
207 PROC_UNLOCK(p);
208 /* Drain the limit callout while we don't have the proc locked */
209 callout_drain(&p->p_limco);
210
211 #ifdef AUDIT
212 /*
213 * The Sun BSM exit token contains two components: an exit status as
214 * passed to exit(), and a return value to indicate what sort of exit
215 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
216 * what the return value is.
217 */
218 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0);
219 AUDIT_SYSCALL_EXIT(0, td);
220 #endif
221
222 /* Are we a task leader? */
223 if (p == p->p_leader) {
224 mtx_lock(&ppeers_lock);
225 q = p->p_peers;
226 while (q != NULL) {
227 PROC_LOCK(q);
228 psignal(q, SIGKILL);
229 PROC_UNLOCK(q);
230 q = q->p_peers;
231 }
232 while (p->p_peers != NULL)
233 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
234 mtx_unlock(&ppeers_lock);
235 }
236
237 /*
238 * Check if any loadable modules need anything done at process exit.
239 * E.g. SYSV IPC stuff
240 * XXX what if one of these generates an error?
241 */
242 EVENTHANDLER_INVOKE(process_exit, p);
243
244 /*
245 * If parent is waiting for us to exit or exec,
246 * P_PPWAIT is set; we will wakeup the parent below.
247 */
248 PROC_LOCK(p);
249 stopprofclock(p);
250 p->p_flag &= ~(P_TRACED | P_PPWAIT);
251
252 /*
253 * Stop the real interval timer. If the handler is currently
254 * executing, prevent it from rearming itself and let it finish.
255 */
256 if (timevalisset(&p->p_realtimer.it_value) &&
257 callout_stop(&p->p_itcallout) == 0) {
258 timevalclear(&p->p_realtimer.it_interval);
259 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
260 KASSERT(!timevalisset(&p->p_realtimer.it_value),
261 ("realtime timer is still armed"));
262 }
263 PROC_UNLOCK(p);
264
265 /*
266 * Reset any sigio structures pointing to us as a result of
267 * F_SETOWN with our pid.
268 */
269 funsetownlst(&p->p_sigiolst);
270
271 /*
272 * If this process has an nlminfo data area (for lockd), release it
273 */
274 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
275 (*nlminfo_release_p)(p);
276
277 /*
278 * Close open files and release open-file table.
279 * This may block!
280 */
281 fdfree(td);
282
283 /*
284 * If this thread tickled GEOM, we need to wait for the giggling to
285 * stop before we return to userland
286 */
287 if (td->td_pflags & TDP_GEOM)
288 g_waitidle();
289
290 /*
291 * Remove ourself from our leader's peer list and wake our leader.
292 */
293 mtx_lock(&ppeers_lock);
294 if (p->p_leader->p_peers) {
295 q = p->p_leader;
296 while (q->p_peers != p)
297 q = q->p_peers;
298 q->p_peers = p->p_peers;
299 wakeup(p->p_leader);
300 }
301 mtx_unlock(&ppeers_lock);
302
303 vmspace_exit(td);
304
305 sx_xlock(&proctree_lock);
306 if (SESS_LEADER(p)) {
307 struct session *sp = p->p_session;
308 struct tty *tp;
309
310 /*
311 * s_ttyp is not zero'd; we use this to indicate that
312 * the session once had a controlling terminal. (for
313 * logging and informational purposes)
314 */
315 SESS_LOCK(sp);
316 ttyvp = sp->s_ttyvp;
317 tp = sp->s_ttyp;
318 sp->s_ttyvp = NULL;
319 sp->s_leader = NULL;
320 SESS_UNLOCK(sp);
321
322 /*
323 * Signal foreground pgrp and revoke access to
324 * controlling terminal if it has not been revoked
325 * already.
326 *
327 * Because the TTY may have been revoked in the mean
328 * time and could already have a new session associated
329 * with it, make sure we don't send a SIGHUP to a
330 * foreground process group that does not belong to this
331 * session.
332 */
333
334 if (tp != NULL) {
335 tty_lock(tp);
336 if (tp->t_session == sp)
337 tty_signal_pgrp(tp, SIGHUP);
338 tty_unlock(tp);
339 }
340
341 if (ttyvp != NULL) {
342 sx_xunlock(&proctree_lock);
343 if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) {
344 VOP_REVOKE(ttyvp, REVOKEALL);
345 VOP_UNLOCK(ttyvp, 0);
346 }
347 sx_xlock(&proctree_lock);
348 }
349 }
350 fixjobc(p, p->p_pgrp, 0);
351 sx_xunlock(&proctree_lock);
352 (void)acct_process(td);
353
354 /* Release the TTY now we've unlocked everything. */
355 if (ttyvp != NULL)
356 vrele(ttyvp);
357 #ifdef KTRACE
358 /*
359 * Disable tracing, then drain any pending records and release
360 * the trace file.
361 */
362 if (p->p_traceflag != 0) {
363 PROC_LOCK(p);
364 mtx_lock(&ktrace_mtx);
365 p->p_traceflag = 0;
366 mtx_unlock(&ktrace_mtx);
367 PROC_UNLOCK(p);
368 ktrprocexit(td);
369 PROC_LOCK(p);
370 mtx_lock(&ktrace_mtx);
371 tracevp = p->p_tracevp;
372 p->p_tracevp = NULL;
373 tracecred = p->p_tracecred;
374 p->p_tracecred = NULL;
375 mtx_unlock(&ktrace_mtx);
376 PROC_UNLOCK(p);
377 if (tracevp != NULL) {
378 locked = VFS_LOCK_GIANT(tracevp->v_mount);
379 vrele(tracevp);
380 VFS_UNLOCK_GIANT(locked);
381 }
382 if (tracecred != NULL)
383 crfree(tracecred);
384 }
385 #endif
386 /*
387 * Release reference to text vnode
388 */
389 if ((vtmp = p->p_textvp) != NULL) {
390 p->p_textvp = NULL;
391 locked = VFS_LOCK_GIANT(vtmp->v_mount);
392 vrele(vtmp);
393 VFS_UNLOCK_GIANT(locked);
394 }
395
396 /*
397 * Release our limits structure.
398 */
399 PROC_LOCK(p);
400 plim = p->p_limit;
401 p->p_limit = NULL;
402 PROC_UNLOCK(p);
403 lim_free(plim);
404
405 /*
406 * Remove proc from allproc queue and pidhash chain.
407 * Place onto zombproc. Unlink from parent's child list.
408 */
409 sx_xlock(&allproc_lock);
410 LIST_REMOVE(p, p_list);
411 LIST_INSERT_HEAD(&zombproc, p, p_list);
412 LIST_REMOVE(p, p_hash);
413 sx_xunlock(&allproc_lock);
414
415 /*
416 * Call machine-dependent code to release any
417 * machine-dependent resources other than the address space.
418 * The address space is released by "vmspace_exitfree(p)" in
419 * vm_waitproc().
420 */
421 cpu_exit(td);
422
423 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
424
425 /*
426 * Reparent all of our children to init.
427 */
428 sx_xlock(&proctree_lock);
429 q = LIST_FIRST(&p->p_children);
430 if (q != NULL) /* only need this if any child is S_ZOMB */
431 wakeup(initproc);
432 for (; q != NULL; q = nq) {
433 nq = LIST_NEXT(q, p_sibling);
434 PROC_LOCK(q);
435 proc_reparent(q, initproc);
436 q->p_sigparent = SIGCHLD;
437 /*
438 * Traced processes are killed
439 * since their existence means someone is screwing up.
440 */
441 if (q->p_flag & P_TRACED) {
442 struct thread *temp;
443
444 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
445 FOREACH_THREAD_IN_PROC(q, temp)
446 temp->td_dbgflags &= ~TDB_SUSPEND;
447 psignal(q, SIGKILL);
448 }
449 PROC_UNLOCK(q);
450 }
451
452 /* Save exit status. */
453 PROC_LOCK(p);
454 p->p_xstat = rv;
455 p->p_xthread = td;
456
457 /* Tell the prison that we are gone. */
458 prison_proc_free(p->p_ucred->cr_prison);
459
460 #ifdef KDTRACE_HOOKS
461 /*
462 * Tell the DTrace fasttrap provider about the exit if it
463 * has declared an interest.
464 */
465 if (dtrace_fasttrap_exit)
466 dtrace_fasttrap_exit(p);
467 #endif
468
469 /*
470 * Notify interested parties of our demise.
471 */
472 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
473
474 #ifdef KDTRACE_HOOKS
475 int reason = CLD_EXITED;
476 if (WCOREDUMP(rv))
477 reason = CLD_DUMPED;
478 else if (WIFSIGNALED(rv))
479 reason = CLD_KILLED;
480 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0);
481 #endif
482
483 /*
484 * Just delete all entries in the p_klist. At this point we won't
485 * report any more events, and there are nasty race conditions that
486 * can beat us if we don't.
487 */
488 knlist_clear(&p->p_klist, 1);
489
490 /*
491 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
492 * flag set, or if the handler is set to SIG_IGN, notify process
493 * 1 instead (and hope it will handle this situation).
494 */
495 PROC_LOCK(p->p_pptr);
496 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
497 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
498 struct proc *pp;
499
500 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
501 pp = p->p_pptr;
502 PROC_UNLOCK(pp);
503 proc_reparent(p, initproc);
504 p->p_sigparent = SIGCHLD;
505 PROC_LOCK(p->p_pptr);
506
507 /*
508 * Notify parent, so in case he was wait(2)ing or
509 * executing waitpid(2) with our pid, he will
510 * continue.
511 */
512 wakeup(pp);
513 } else
514 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
515
516 if (p->p_pptr == initproc)
517 psignal(p->p_pptr, SIGCHLD);
518 else if (p->p_sigparent != 0) {
519 if (p->p_sigparent == SIGCHLD)
520 childproc_exited(p);
521 else /* LINUX thread */
522 psignal(p->p_pptr, p->p_sigparent);
523 }
524 sx_xunlock(&proctree_lock);
525
526 /*
527 * The state PRS_ZOMBIE prevents other proesses from sending
528 * signal to the process, to avoid memory leak, we free memory
529 * for signal queue at the time when the state is set.
530 */
531 sigqueue_flush(&p->p_sigqueue);
532 sigqueue_flush(&td->td_sigqueue);
533
534 /*
535 * We have to wait until after acquiring all locks before
536 * changing p_state. We need to avoid all possible context
537 * switches (including ones from blocking on a mutex) while
538 * marked as a zombie. We also have to set the zombie state
539 * before we release the parent process' proc lock to avoid
540 * a lost wakeup. So, we first call wakeup, then we grab the
541 * sched lock, update the state, and release the parent process'
542 * proc lock.
543 */
544 wakeup(p->p_pptr);
545 cv_broadcast(&p->p_pwait);
546 sched_exit(p->p_pptr, td);
547 PROC_SLOCK(p);
548 p->p_state = PRS_ZOMBIE;
549 PROC_UNLOCK(p->p_pptr);
550
551 /*
552 * Hopefully no one will try to deliver a signal to the process this
553 * late in the game.
554 */
555 knlist_destroy(&p->p_klist);
556
557 /*
558 * Save our children's rusage information in our exit rusage.
559 */
560 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
561
562 /*
563 * Make sure the scheduler takes this thread out of its tables etc.
564 * This will also release this thread's reference to the ucred.
565 * Other thread parts to release include pcb bits and such.
566 */
567 thread_exit();
568 }
569
570
571 #ifndef _SYS_SYSPROTO_H_
572 struct abort2_args {
573 char *why;
574 int nargs;
575 void **args;
576 };
577 #endif
578
579 int
580 abort2(struct thread *td, struct abort2_args *uap)
581 {
582 struct proc *p = td->td_proc;
583 struct sbuf *sb;
584 void *uargs[16];
585 int error, i, sig;
586
587 /*
588 * Do it right now so we can log either proper call of abort2(), or
589 * note, that invalid argument was passed. 512 is big enough to
590 * handle 16 arguments' descriptions with additional comments.
591 */
592 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
593 sbuf_clear(sb);
594 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
595 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
596 /*
597 * Since we can't return from abort2(), send SIGKILL in cases, where
598 * abort2() was called improperly
599 */
600 sig = SIGKILL;
601 /* Prevent from DoSes from user-space. */
602 if (uap->nargs < 0 || uap->nargs > 16)
603 goto out;
604 if (uap->nargs > 0) {
605 if (uap->args == NULL)
606 goto out;
607 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
608 if (error != 0)
609 goto out;
610 }
611 /*
612 * Limit size of 'reason' string to 128. Will fit even when
613 * maximal number of arguments was chosen to be logged.
614 */
615 if (uap->why != NULL) {
616 error = sbuf_copyin(sb, uap->why, 128);
617 if (error < 0)
618 goto out;
619 } else {
620 sbuf_printf(sb, "(null)");
621 }
622 if (uap->nargs > 0) {
623 sbuf_printf(sb, "(");
624 for (i = 0;i < uap->nargs; i++)
625 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
626 sbuf_printf(sb, ")");
627 }
628 /*
629 * Final stage: arguments were proper, string has been
630 * successfully copied from userspace, and copying pointers
631 * from user-space succeed.
632 */
633 sig = SIGABRT;
634 out:
635 if (sig == SIGKILL) {
636 sbuf_trim(sb);
637 sbuf_printf(sb, " (Reason text inaccessible)");
638 }
639 sbuf_cat(sb, "\n");
640 sbuf_finish(sb);
641 log(LOG_INFO, "%s", sbuf_data(sb));
642 sbuf_delete(sb);
643 exit1(td, W_EXITCODE(0, sig));
644 return (0);
645 }
646
647
648 #ifdef COMPAT_43
649 /*
650 * The dirty work is handled by kern_wait().
651 */
652 int
653 owait(struct thread *td, struct owait_args *uap __unused)
654 {
655 int error, status;
656
657 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
658 if (error == 0)
659 td->td_retval[1] = status;
660 return (error);
661 }
662 #endif /* COMPAT_43 */
663
664 /*
665 * The dirty work is handled by kern_wait().
666 */
667 int
668 wait4(struct thread *td, struct wait_args *uap)
669 {
670 struct rusage ru, *rup;
671 int error, status;
672
673 if (uap->rusage != NULL)
674 rup = &ru;
675 else
676 rup = NULL;
677 error = kern_wait(td, uap->pid, &status, uap->options, rup);
678 if (uap->status != NULL && error == 0)
679 error = copyout(&status, uap->status, sizeof(status));
680 if (uap->rusage != NULL && error == 0)
681 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
682 return (error);
683 }
684
685 /*
686 * Reap the remains of a zombie process and optionally return status and
687 * rusage. Asserts and will release both the proctree_lock and the process
688 * lock as part of its work.
689 */
690 static void
691 proc_reap(struct thread *td, struct proc *p, int *status, int options,
692 struct rusage *rusage)
693 {
694 struct proc *q, *t;
695
696 sx_assert(&proctree_lock, SA_XLOCKED);
697 PROC_LOCK_ASSERT(p, MA_OWNED);
698 PROC_SLOCK_ASSERT(p, MA_OWNED);
699 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
700
701 q = td->td_proc;
702 if (rusage) {
703 *rusage = p->p_ru;
704 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
705 }
706 PROC_SUNLOCK(p);
707 td->td_retval[0] = p->p_pid;
708 if (status)
709 *status = p->p_xstat; /* convert to int */
710 if (options & WNOWAIT) {
711 /*
712 * Only poll, returning the status. Caller does not wish to
713 * release the proc struct just yet.
714 */
715 PROC_UNLOCK(p);
716 sx_xunlock(&proctree_lock);
717 return;
718 }
719
720 PROC_LOCK(q);
721 sigqueue_take(p->p_ksi);
722 PROC_UNLOCK(q);
723 PROC_UNLOCK(p);
724
725 /*
726 * If we got the child via a ptrace 'attach', we need to give it back
727 * to the old parent.
728 */
729 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
730 PROC_LOCK(p);
731 p->p_oppid = 0;
732 proc_reparent(p, t);
733 PROC_UNLOCK(p);
734 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
735 wakeup(t);
736 cv_broadcast(&p->p_pwait);
737 PROC_UNLOCK(t);
738 sx_xunlock(&proctree_lock);
739 return;
740 }
741
742 /*
743 * Remove other references to this process to ensure we have an
744 * exclusive reference.
745 */
746 sx_xlock(&allproc_lock);
747 LIST_REMOVE(p, p_list); /* off zombproc */
748 sx_xunlock(&allproc_lock);
749 LIST_REMOVE(p, p_sibling);
750 leavepgrp(p);
751 sx_xunlock(&proctree_lock);
752
753 /*
754 * As a side effect of this lock, we know that all other writes to
755 * this proc are visible now, so no more locking is needed for p.
756 */
757 PROC_LOCK(p);
758 p->p_xstat = 0; /* XXX: why? */
759 PROC_UNLOCK(p);
760 PROC_LOCK(q);
761 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
762 PROC_UNLOCK(q);
763
764 /*
765 * Decrement the count of procs running with this uid.
766 */
767 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
768
769 /*
770 * Free credentials, arguments, and sigacts.
771 */
772 crfree(p->p_ucred);
773 p->p_ucred = NULL;
774 pargs_drop(p->p_args);
775 p->p_args = NULL;
776 sigacts_free(p->p_sigacts);
777 p->p_sigacts = NULL;
778
779 /*
780 * Do any thread-system specific cleanups.
781 */
782 thread_wait(p);
783
784 /*
785 * Give vm and machine-dependent layer a chance to free anything that
786 * cpu_exit couldn't release while still running in process context.
787 */
788 vm_waitproc(p);
789 #ifdef MAC
790 mac_proc_destroy(p);
791 #endif
792 KASSERT(FIRST_THREAD_IN_PROC(p),
793 ("proc_reap: no residual thread!"));
794 uma_zfree(proc_zone, p);
795 sx_xlock(&allproc_lock);
796 nprocs--;
797 sx_xunlock(&allproc_lock);
798 }
799
800 int
801 kern_wait(struct thread *td, pid_t pid, int *status, int options,
802 struct rusage *rusage)
803 {
804 struct proc *p, *q;
805 int error, nfound;
806
807 AUDIT_ARG_PID(pid);
808 AUDIT_ARG_VALUE(options);
809
810 q = td->td_proc;
811 if (pid == 0) {
812 PROC_LOCK(q);
813 pid = -q->p_pgid;
814 PROC_UNLOCK(q);
815 }
816 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE))
817 return (EINVAL);
818 loop:
819 if (q->p_flag & P_STATCHILD) {
820 PROC_LOCK(q);
821 q->p_flag &= ~P_STATCHILD;
822 PROC_UNLOCK(q);
823 }
824 nfound = 0;
825 sx_xlock(&proctree_lock);
826 LIST_FOREACH(p, &q->p_children, p_sibling) {
827 PROC_LOCK(p);
828 if (pid != WAIT_ANY &&
829 p->p_pid != pid && p->p_pgid != -pid) {
830 PROC_UNLOCK(p);
831 continue;
832 }
833 if (p_canwait(td, p)) {
834 PROC_UNLOCK(p);
835 continue;
836 }
837
838 /*
839 * This special case handles a kthread spawned by linux_clone
840 * (see linux_misc.c). The linux_wait4 and linux_waitpid
841 * functions need to be able to distinguish between waiting
842 * on a process and waiting on a thread. It is a thread if
843 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
844 * signifies we want to wait for threads and not processes.
845 */
846 if ((p->p_sigparent != SIGCHLD) ^
847 ((options & WLINUXCLONE) != 0)) {
848 PROC_UNLOCK(p);
849 continue;
850 }
851
852 nfound++;
853 PROC_SLOCK(p);
854 if (p->p_state == PRS_ZOMBIE) {
855 proc_reap(td, p, status, options, rusage);
856 return (0);
857 }
858 if ((p->p_flag & P_STOPPED_SIG) &&
859 (p->p_suspcount == p->p_numthreads) &&
860 (p->p_flag & P_WAITED) == 0 &&
861 (p->p_flag & P_TRACED || options & WUNTRACED)) {
862 PROC_SUNLOCK(p);
863 p->p_flag |= P_WAITED;
864 sx_xunlock(&proctree_lock);
865 td->td_retval[0] = p->p_pid;
866 if (status)
867 *status = W_STOPCODE(p->p_xstat);
868
869 PROC_LOCK(q);
870 sigqueue_take(p->p_ksi);
871 PROC_UNLOCK(q);
872 PROC_UNLOCK(p);
873
874 return (0);
875 }
876 PROC_SUNLOCK(p);
877 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
878 sx_xunlock(&proctree_lock);
879 td->td_retval[0] = p->p_pid;
880 p->p_flag &= ~P_CONTINUED;
881
882 PROC_LOCK(q);
883 sigqueue_take(p->p_ksi);
884 PROC_UNLOCK(q);
885 PROC_UNLOCK(p);
886
887 if (status)
888 *status = SIGCONT;
889 return (0);
890 }
891 PROC_UNLOCK(p);
892 }
893 if (nfound == 0) {
894 sx_xunlock(&proctree_lock);
895 return (ECHILD);
896 }
897 if (options & WNOHANG) {
898 sx_xunlock(&proctree_lock);
899 td->td_retval[0] = 0;
900 return (0);
901 }
902 PROC_LOCK(q);
903 sx_xunlock(&proctree_lock);
904 if (q->p_flag & P_STATCHILD) {
905 q->p_flag &= ~P_STATCHILD;
906 error = 0;
907 } else
908 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
909 PROC_UNLOCK(q);
910 if (error)
911 return (error);
912 goto loop;
913 }
914
915 /*
916 * Make process 'parent' the new parent of process 'child'.
917 * Must be called with an exclusive hold of proctree lock.
918 */
919 void
920 proc_reparent(struct proc *child, struct proc *parent)
921 {
922
923 sx_assert(&proctree_lock, SX_XLOCKED);
924 PROC_LOCK_ASSERT(child, MA_OWNED);
925 if (child->p_pptr == parent)
926 return;
927
928 PROC_LOCK(child->p_pptr);
929 sigqueue_take(child->p_ksi);
930 PROC_UNLOCK(child->p_pptr);
931 LIST_REMOVE(child, p_sibling);
932 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
933 child->p_pptr = parent;
934 }
Cache object: e6bd16ef8351e841847f9a56faf53c65
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