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("$FreeBSD$");
39
40 #include "opt_compat.h"
41 #include "opt_ktrace.h"
42 #include "opt_mac.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/tty.h>
55 #include <sys/wait.h>
56 #include <sys/vmmeter.h>
57 #include <sys/vnode.h>
58 #include <sys/resourcevar.h>
59 #include <sys/sbuf.h>
60 #include <sys/signalvar.h>
61 #include <sys/sched.h>
62 #include <sys/sx.h>
63 #include <sys/syscallsubr.h>
64 #include <sys/syslog.h>
65 #include <sys/ptrace.h>
66 #include <sys/acct.h> /* for acct_process() function prototype */
67 #include <sys/filedesc.h>
68 #include <sys/shm.h>
69 #include <sys/sem.h>
70 #ifdef KTRACE
71 #include <sys/ktrace.h>
72 #endif
73
74 #include <security/audit/audit.h>
75 #include <security/mac/mac_framework.h>
76
77 #include <vm/vm.h>
78 #include <vm/vm_extern.h>
79 #include <vm/vm_param.h>
80 #include <vm/pmap.h>
81 #include <vm/vm_map.h>
82 #include <vm/vm_page.h>
83 #include <vm/uma.h>
84
85 /* Required to be non-static for SysVR4 emulator */
86 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
87
88 /* Hook for NFS teardown procedure. */
89 void (*nlminfo_release_p)(struct proc *p);
90
91 /*
92 * exit -- death of process.
93 */
94 void
95 sys_exit(struct thread *td, struct sys_exit_args *uap)
96 {
97
98 exit1(td, W_EXITCODE(uap->rval, 0));
99 /* NOTREACHED */
100 }
101
102 /*
103 * Exit: deallocate address space and other resources, change proc state to
104 * zombie, and unlink proc from allproc and parent's lists. Save exit status
105 * and rusage for wait(). Check for child processes and orphan them.
106 */
107 void
108 exit1(struct thread *td, int rv)
109 {
110 struct proc *p, *nq, *q;
111 struct tty *tp;
112 struct vnode *ttyvp;
113 struct vnode *vtmp;
114 #ifdef KTRACE
115 struct vnode *tracevp;
116 struct ucred *tracecred;
117 #endif
118 struct plimit *plim;
119 int locked;
120
121 /*
122 * Drop Giant if caller has it. Eventually we should warn about
123 * being called with Giant held.
124 */
125 while (mtx_owned(&Giant))
126 mtx_unlock(&Giant);
127
128 p = td->td_proc;
129 if (p == initproc) {
130 printf("init died (signal %d, exit %d)\n",
131 WTERMSIG(rv), WEXITSTATUS(rv));
132 panic("Going nowhere without my init!");
133 }
134
135 /*
136 * MUST abort all other threads before proceeding past here.
137 */
138 PROC_LOCK(p);
139 if (p->p_flag & P_HADTHREADS) {
140 retry:
141 /*
142 * First check if some other thread got here before us..
143 * if so, act apropriatly, (exit or suspend);
144 */
145 thread_suspend_check(0);
146
147 /*
148 * Kill off the other threads. This requires
149 * some co-operation from other parts of the kernel
150 * so it may not be instantaneous. With this state set
151 * any thread entering the kernel from userspace will
152 * thread_exit() in trap(). Any thread attempting to
153 * sleep will return immediately with EINTR or EWOULDBLOCK
154 * which will hopefully force them to back out to userland
155 * freeing resources as they go. Any thread attempting
156 * to return to userland will thread_exit() from userret().
157 * thread_exit() will unsuspend us when the last of the
158 * other threads exits.
159 * If there is already a thread singler after resumption,
160 * calling thread_single will fail; in that case, we just
161 * re-check all suspension request, the thread should
162 * either be suspended there or exit.
163 */
164 if (thread_single(SINGLE_EXIT))
165 goto retry;
166
167 /*
168 * All other activity in this process is now stopped.
169 * Threading support has been turned off.
170 */
171 }
172 KASSERT(p->p_numthreads == 1,
173 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
174 /*
175 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
176 * on our vmspace, so we should block below until they have
177 * released their reference to us. Note that if they have
178 * requested S_EXIT stops we will block here until they ack
179 * via PIOCCONT.
180 */
181 _STOPEVENT(p, S_EXIT, rv);
182
183 /*
184 * Note that we are exiting and do another wakeup of anyone in
185 * PIOCWAIT in case they aren't listening for S_EXIT stops or
186 * decided to wait again after we told them we are exiting.
187 */
188 p->p_flag |= P_WEXIT;
189 wakeup(&p->p_stype);
190
191 /*
192 * Wait for any processes that have a hold on our vmspace to
193 * release their reference.
194 */
195 while (p->p_lock > 0)
196 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
197
198 PROC_UNLOCK(p);
199 /* Drain the limit callout while we don't have the proc locked */
200 callout_drain(&p->p_limco);
201
202 #ifdef AUDIT
203 /*
204 * The Sun BSM exit token contains two components: an exit status as
205 * passed to exit(), and a return value to indicate what sort of exit
206 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
207 * what the return value is.
208 */
209 AUDIT_ARG(exit, WEXITSTATUS(rv), 0);
210 AUDIT_SYSCALL_EXIT(0, td);
211 #endif
212
213 /* Are we a task leader? */
214 if (p == p->p_leader) {
215 mtx_lock(&ppeers_lock);
216 q = p->p_peers;
217 while (q != NULL) {
218 PROC_LOCK(q);
219 psignal(q, SIGKILL);
220 PROC_UNLOCK(q);
221 q = q->p_peers;
222 }
223 while (p->p_peers != NULL)
224 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
225 mtx_unlock(&ppeers_lock);
226 }
227
228 /*
229 * Check if any loadable modules need anything done at process exit.
230 * E.g. SYSV IPC stuff
231 * XXX what if one of these generates an error?
232 */
233 EVENTHANDLER_INVOKE(process_exit, p);
234
235 /*
236 * If parent is waiting for us to exit or exec,
237 * P_PPWAIT is set; we will wakeup the parent below.
238 */
239 PROC_LOCK(p);
240 stopprofclock(p);
241 p->p_flag &= ~(P_TRACED | P_PPWAIT);
242
243 /*
244 * Stop the real interval timer. If the handler is currently
245 * executing, prevent it from rearming itself and let it finish.
246 */
247 if (timevalisset(&p->p_realtimer.it_value) &&
248 callout_stop(&p->p_itcallout) == 0) {
249 timevalclear(&p->p_realtimer.it_interval);
250 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
251 KASSERT(!timevalisset(&p->p_realtimer.it_value),
252 ("realtime timer is still armed"));
253 }
254 PROC_UNLOCK(p);
255
256 /*
257 * Reset any sigio structures pointing to us as a result of
258 * F_SETOWN with our pid.
259 */
260 funsetownlst(&p->p_sigiolst);
261
262 /*
263 * If this process has an nlminfo data area (for lockd), release it
264 */
265 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
266 (*nlminfo_release_p)(p);
267
268 /*
269 * Close open files and release open-file table.
270 * This may block!
271 */
272 fdfree(td);
273
274 /*
275 * If this thread tickled GEOM, we need to wait for the giggling to
276 * stop before we return to userland
277 */
278 if (td->td_pflags & TDP_GEOM)
279 g_waitidle();
280
281 /*
282 * Remove ourself from our leader's peer list and wake our leader.
283 */
284 mtx_lock(&ppeers_lock);
285 if (p->p_leader->p_peers) {
286 q = p->p_leader;
287 while (q->p_peers != p)
288 q = q->p_peers;
289 q->p_peers = p->p_peers;
290 wakeup(p->p_leader);
291 }
292 mtx_unlock(&ppeers_lock);
293
294 vmspace_exit(td);
295
296 mtx_lock(&Giant); /* XXX TTY */
297 sx_xlock(&proctree_lock);
298 if (SESS_LEADER(p)) {
299 struct session *sp;
300
301 sp = p->p_session;
302 if (sp->s_ttyvp) {
303 /*
304 * Controlling process.
305 * Signal foreground pgrp,
306 * drain controlling terminal
307 * and revoke access to controlling terminal.
308 */
309 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
310 tp = sp->s_ttyp;
311 if (sp->s_ttyp->t_pgrp) {
312 PGRP_LOCK(sp->s_ttyp->t_pgrp);
313 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
314 PGRP_UNLOCK(sp->s_ttyp->t_pgrp);
315 }
316 /* XXX tp should be locked. */
317 sx_xunlock(&proctree_lock);
318 (void) ttywait(tp);
319 sx_xlock(&proctree_lock);
320 /*
321 * The tty could have been revoked
322 * if we blocked.
323 */
324 if (sp->s_ttyvp) {
325 ttyvp = sp->s_ttyvp;
326 SESS_LOCK(p->p_session);
327 sp->s_ttyvp = NULL;
328 SESS_UNLOCK(p->p_session);
329 sx_xunlock(&proctree_lock);
330 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td);
331 VOP_REVOKE(ttyvp, REVOKEALL);
332 vput(ttyvp);
333 sx_xlock(&proctree_lock);
334 }
335 }
336 if (sp->s_ttyvp) {
337 ttyvp = sp->s_ttyvp;
338 SESS_LOCK(p->p_session);
339 sp->s_ttyvp = NULL;
340 SESS_UNLOCK(p->p_session);
341 vrele(ttyvp);
342 }
343 /*
344 * s_ttyp is not zero'd; we use this to indicate
345 * that the session once had a controlling terminal.
346 * (for logging and informational purposes)
347 */
348 }
349 SESS_LOCK(p->p_session);
350 sp->s_leader = NULL;
351 SESS_UNLOCK(p->p_session);
352 }
353 fixjobc(p, p->p_pgrp, 0);
354 sx_xunlock(&proctree_lock);
355 (void)acct_process(td);
356 mtx_unlock(&Giant);
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 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
443 psignal(q, SIGKILL);
444 }
445 PROC_UNLOCK(q);
446 }
447
448 /* Save exit status. */
449 PROC_LOCK(p);
450 p->p_xstat = rv;
451 p->p_xthread = td;
452 /*
453 * Notify interested parties of our demise.
454 */
455 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
456
457 /*
458 * Just delete all entries in the p_klist. At this point we won't
459 * report any more events, and there are nasty race conditions that
460 * can beat us if we don't.
461 */
462 knlist_clear(&p->p_klist, 1);
463
464 /*
465 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
466 * flag set, or if the handler is set to SIG_IGN, notify process
467 * 1 instead (and hope it will handle this situation).
468 */
469 PROC_LOCK(p->p_pptr);
470 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
471 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
472 struct proc *pp;
473
474 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
475 pp = p->p_pptr;
476 PROC_UNLOCK(pp);
477 proc_reparent(p, initproc);
478 p->p_sigparent = SIGCHLD;
479 PROC_LOCK(p->p_pptr);
480 /*
481 * If this was the last child of our parent, notify
482 * parent, so in case he was wait(2)ing, he will
483 * continue.
484 */
485 if (LIST_EMPTY(&pp->p_children))
486 wakeup(pp);
487 } else
488 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
489
490 if (p->p_pptr == initproc)
491 psignal(p->p_pptr, SIGCHLD);
492 else if (p->p_sigparent != 0) {
493 if (p->p_sigparent == SIGCHLD)
494 childproc_exited(p);
495 else /* LINUX thread */
496 psignal(p->p_pptr, p->p_sigparent);
497 }
498 sx_xunlock(&proctree_lock);
499
500 /*
501 * The state PRS_ZOMBIE prevents other proesses from sending
502 * signal to the process, to avoid memory leak, we free memory
503 * for signal queue at the time when the state is set.
504 */
505 sigqueue_flush(&p->p_sigqueue);
506 sigqueue_flush(&td->td_sigqueue);
507
508 /*
509 * We have to wait until after acquiring all locks before
510 * changing p_state. We need to avoid all possible context
511 * switches (including ones from blocking on a mutex) while
512 * marked as a zombie. We also have to set the zombie state
513 * before we release the parent process' proc lock to avoid
514 * a lost wakeup. So, we first call wakeup, then we grab the
515 * sched lock, update the state, and release the parent process'
516 * proc lock.
517 */
518 wakeup(p->p_pptr);
519 PROC_SLOCK(p->p_pptr);
520 sched_exit(p->p_pptr, td);
521 PROC_SUNLOCK(p->p_pptr);
522 PROC_SLOCK(p);
523 p->p_state = PRS_ZOMBIE;
524 PROC_UNLOCK(p->p_pptr);
525
526 /*
527 * Hopefully no one will try to deliver a signal to the process this
528 * late in the game.
529 */
530 knlist_destroy(&p->p_klist);
531
532 /*
533 * Save our children's rusage information in our exit rusage.
534 */
535 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
536
537 /*
538 * Make sure the scheduler takes this thread out of its tables etc.
539 * This will also release this thread's reference to the ucred.
540 * Other thread parts to release include pcb bits and such.
541 */
542 thread_exit();
543 }
544
545
546 #ifndef _SYS_SYSPROTO_H_
547 struct abort2_args {
548 char *why;
549 int nargs;
550 void **args;
551 };
552 #endif
553
554 int
555 abort2(struct thread *td, struct abort2_args *uap)
556 {
557 struct proc *p = td->td_proc;
558 struct sbuf *sb;
559 void *uargs[16];
560 int error, i, sig;
561
562 error = 0; /* satisfy compiler */
563
564 /*
565 * Do it right now so we can log either proper call of abort2(), or
566 * note, that invalid argument was passed. 512 is big enough to
567 * handle 16 arguments' descriptions with additional comments.
568 */
569 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
570 sbuf_clear(sb);
571 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
572 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
573 /*
574 * Since we can't return from abort2(), send SIGKILL in cases, where
575 * abort2() was called improperly
576 */
577 sig = SIGKILL;
578 /* Prevent from DoSes from user-space. */
579 if (uap->nargs < 0 || uap->nargs > 16)
580 goto out;
581 if (uap->args == NULL)
582 goto out;
583 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
584 if (error != 0)
585 goto out;
586 /*
587 * Limit size of 'reason' string to 128. Will fit even when
588 * maximal number of arguments was chosen to be logged.
589 */
590 if (uap->why != NULL) {
591 error = sbuf_copyin(sb, uap->why, 128);
592 if (error < 0)
593 goto out;
594 } else {
595 sbuf_printf(sb, "(null)");
596 }
597 if (uap->nargs) {
598 sbuf_printf(sb, "(");
599 for (i = 0;i < uap->nargs; i++)
600 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
601 sbuf_printf(sb, ")");
602 }
603 /*
604 * Final stage: arguments were proper, string has been
605 * successfully copied from userspace, and copying pointers
606 * from user-space succeed.
607 */
608 sig = SIGABRT;
609 out:
610 if (sig == SIGKILL) {
611 sbuf_trim(sb);
612 sbuf_printf(sb, " (Reason text inaccessible)");
613 }
614 sbuf_cat(sb, "\n");
615 sbuf_finish(sb);
616 log(LOG_INFO, "%s", sbuf_data(sb));
617 sbuf_delete(sb);
618 exit1(td, W_EXITCODE(0, sig));
619 return (0);
620 }
621
622
623 #ifdef COMPAT_43
624 /*
625 * The dirty work is handled by kern_wait().
626 */
627 int
628 owait(struct thread *td, struct owait_args *uap __unused)
629 {
630 int error, status;
631
632 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
633 if (error == 0)
634 td->td_retval[1] = status;
635 return (error);
636 }
637 #endif /* COMPAT_43 */
638
639 /*
640 * The dirty work is handled by kern_wait().
641 */
642 int
643 wait4(struct thread *td, struct wait_args *uap)
644 {
645 struct rusage ru, *rup;
646 int error, status;
647
648 if (uap->rusage != NULL)
649 rup = &ru;
650 else
651 rup = NULL;
652 error = kern_wait(td, uap->pid, &status, uap->options, rup);
653 if (uap->status != NULL && error == 0)
654 error = copyout(&status, uap->status, sizeof(status));
655 if (uap->rusage != NULL && error == 0)
656 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
657 return (error);
658 }
659
660 int
661 kern_wait(struct thread *td, pid_t pid, int *status, int options,
662 struct rusage *rusage)
663 {
664 struct proc *p, *q, *t;
665 int error, nfound;
666
667 AUDIT_ARG(pid, pid);
668
669 q = td->td_proc;
670 if (pid == 0) {
671 PROC_LOCK(q);
672 pid = -q->p_pgid;
673 PROC_UNLOCK(q);
674 }
675 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
676 return (EINVAL);
677 loop:
678 if (q->p_flag & P_STATCHILD) {
679 PROC_LOCK(q);
680 q->p_flag &= ~P_STATCHILD;
681 PROC_UNLOCK(q);
682 }
683 nfound = 0;
684 sx_xlock(&proctree_lock);
685 LIST_FOREACH(p, &q->p_children, p_sibling) {
686 PROC_LOCK(p);
687 if (pid != WAIT_ANY &&
688 p->p_pid != pid && p->p_pgid != -pid) {
689 PROC_UNLOCK(p);
690 continue;
691 }
692 if (p_canwait(td, p)) {
693 PROC_UNLOCK(p);
694 continue;
695 }
696
697 /*
698 * This special case handles a kthread spawned by linux_clone
699 * (see linux_misc.c). The linux_wait4 and linux_waitpid
700 * functions need to be able to distinguish between waiting
701 * on a process and waiting on a thread. It is a thread if
702 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
703 * signifies we want to wait for threads and not processes.
704 */
705 if ((p->p_sigparent != SIGCHLD) ^
706 ((options & WLINUXCLONE) != 0)) {
707 PROC_UNLOCK(p);
708 continue;
709 }
710
711 nfound++;
712 PROC_SLOCK(p);
713 if (p->p_state == PRS_ZOMBIE) {
714 if (rusage) {
715 *rusage = p->p_ru;
716 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
717 }
718 PROC_SUNLOCK(p);
719 td->td_retval[0] = p->p_pid;
720 if (status)
721 *status = p->p_xstat; /* convert to int */
722 PROC_LOCK(q);
723 sigqueue_take(p->p_ksi);
724 PROC_UNLOCK(q);
725
726 /*
727 * If we got the child via a ptrace 'attach',
728 * we need to give it back to the old parent.
729 */
730 PROC_UNLOCK(p);
731 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
732 PROC_LOCK(p);
733 p->p_oppid = 0;
734 proc_reparent(p, t);
735 PROC_UNLOCK(p);
736 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
737 wakeup(t);
738 PROC_UNLOCK(t);
739 sx_xunlock(&proctree_lock);
740 return (0);
741 }
742
743 /*
744 * Remove other references to this process to ensure
745 * we have an exclusive reference.
746 */
747 sx_xlock(&allproc_lock);
748 LIST_REMOVE(p, p_list); /* off zombproc */
749 sx_xunlock(&allproc_lock);
750 LIST_REMOVE(p, p_sibling);
751 leavepgrp(p);
752 sx_xunlock(&proctree_lock);
753
754 /*
755 * As a side effect of this lock, we know that
756 * all other writes to this proc are visible now, so
757 * no more locking is needed for p.
758 */
759 PROC_LOCK(p);
760 p->p_xstat = 0; /* XXX: why? */
761 PROC_UNLOCK(p);
762 PROC_LOCK(q);
763 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru,
764 &p->p_rux);
765 PROC_UNLOCK(q);
766
767 /*
768 * Decrement the count of procs running with this uid.
769 */
770 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
771
772 /*
773 * Free credentials, arguments, and sigacts.
774 */
775 crfree(p->p_ucred);
776 p->p_ucred = NULL;
777 pargs_drop(p->p_args);
778 p->p_args = NULL;
779 sigacts_free(p->p_sigacts);
780 p->p_sigacts = NULL;
781
782 /*
783 * Do any thread-system specific cleanups.
784 */
785 thread_wait(p);
786
787 /*
788 * Give vm and machine-dependent layer a chance
789 * to free anything that cpu_exit couldn't
790 * release while still running in process context.
791 */
792 vm_waitproc(p);
793 #ifdef MAC
794 mac_destroy_proc(p);
795 #endif
796 KASSERT(FIRST_THREAD_IN_PROC(p),
797 ("kern_wait: no residual thread!"));
798 uma_zfree(proc_zone, p);
799 sx_xlock(&allproc_lock);
800 nprocs--;
801 sx_xunlock(&allproc_lock);
802 return (0);
803 }
804 if ((p->p_flag & P_STOPPED_SIG) &&
805 (p->p_suspcount == p->p_numthreads) &&
806 (p->p_flag & P_WAITED) == 0 &&
807 (p->p_flag & P_TRACED || options & WUNTRACED)) {
808 PROC_SUNLOCK(p);
809 p->p_flag |= P_WAITED;
810 sx_xunlock(&proctree_lock);
811 td->td_retval[0] = p->p_pid;
812 if (status)
813 *status = W_STOPCODE(p->p_xstat);
814
815 PROC_LOCK(q);
816 sigqueue_take(p->p_ksi);
817 PROC_UNLOCK(q);
818 PROC_UNLOCK(p);
819
820 return (0);
821 }
822 PROC_SUNLOCK(p);
823 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
824 sx_xunlock(&proctree_lock);
825 td->td_retval[0] = p->p_pid;
826 p->p_flag &= ~P_CONTINUED;
827
828 PROC_LOCK(q);
829 sigqueue_take(p->p_ksi);
830 PROC_UNLOCK(q);
831 PROC_UNLOCK(p);
832
833 if (status)
834 *status = SIGCONT;
835 return (0);
836 }
837 PROC_UNLOCK(p);
838 }
839 if (nfound == 0) {
840 sx_xunlock(&proctree_lock);
841 return (ECHILD);
842 }
843 if (options & WNOHANG) {
844 sx_xunlock(&proctree_lock);
845 td->td_retval[0] = 0;
846 return (0);
847 }
848 PROC_LOCK(q);
849 sx_xunlock(&proctree_lock);
850 if (q->p_flag & P_STATCHILD) {
851 q->p_flag &= ~P_STATCHILD;
852 error = 0;
853 } else
854 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
855 PROC_UNLOCK(q);
856 if (error)
857 return (error);
858 goto loop;
859 }
860
861 /*
862 * Make process 'parent' the new parent of process 'child'.
863 * Must be called with an exclusive hold of proctree lock.
864 */
865 void
866 proc_reparent(struct proc *child, struct proc *parent)
867 {
868
869 sx_assert(&proctree_lock, SX_XLOCKED);
870 PROC_LOCK_ASSERT(child, MA_OWNED);
871 if (child->p_pptr == parent)
872 return;
873
874 PROC_LOCK(child->p_pptr);
875 sigqueue_take(child->p_ksi);
876 PROC_UNLOCK(child->p_pptr);
877 LIST_REMOVE(child, p_sibling);
878 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
879 child->p_pptr = parent;
880 }
Cache object: cc295fb2214317f853de1834abcc9a77
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