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/11.0/sys/kern/kern_exit.c 303141 2016-07-21 12:50:23Z kib $");
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 #include <vm/vm_domain.h>
90
91 #ifdef KDTRACE_HOOKS
92 #include <sys/dtrace_bsd.h>
93 dtrace_execexit_func_t dtrace_fasttrap_exit;
94 #endif
95
96 SDT_PROVIDER_DECLARE(proc);
97 SDT_PROBE_DEFINE1(proc, , , exit, "int");
98
99 /* Hook for NFS teardown procedure. */
100 void (*nlminfo_release_p)(struct proc *p);
101
102 struct proc *
103 proc_realparent(struct proc *child)
104 {
105 struct proc *p, *parent;
106
107 sx_assert(&proctree_lock, SX_LOCKED);
108 if ((child->p_treeflag & P_TREE_ORPHANED) == 0) {
109 if (child->p_oppid == 0 ||
110 child->p_pptr->p_pid == child->p_oppid)
111 parent = child->p_pptr;
112 else
113 parent = initproc;
114 return (parent);
115 }
116 for (p = child; (p->p_treeflag & P_TREE_FIRST_ORPHAN) == 0;) {
117 /* Cannot use LIST_PREV(), since the list head is not known. */
118 p = __containerof(p->p_orphan.le_prev, struct proc,
119 p_orphan.le_next);
120 KASSERT((p->p_treeflag & P_TREE_ORPHANED) != 0,
121 ("missing P_ORPHAN %p", p));
122 }
123 parent = __containerof(p->p_orphan.le_prev, struct proc,
124 p_orphans.lh_first);
125 return (parent);
126 }
127
128 void
129 reaper_abandon_children(struct proc *p, bool exiting)
130 {
131 struct proc *p1, *p2, *ptmp;
132
133 sx_assert(&proctree_lock, SX_LOCKED);
134 KASSERT(p != initproc, ("reaper_abandon_children for initproc"));
135 if ((p->p_treeflag & P_TREE_REAPER) == 0)
136 return;
137 p1 = p->p_reaper;
138 LIST_FOREACH_SAFE(p2, &p->p_reaplist, p_reapsibling, ptmp) {
139 LIST_REMOVE(p2, p_reapsibling);
140 p2->p_reaper = p1;
141 p2->p_reapsubtree = p->p_reapsubtree;
142 LIST_INSERT_HEAD(&p1->p_reaplist, p2, p_reapsibling);
143 if (exiting && p2->p_pptr == p) {
144 PROC_LOCK(p2);
145 proc_reparent(p2, p1);
146 PROC_UNLOCK(p2);
147 }
148 }
149 KASSERT(LIST_EMPTY(&p->p_reaplist), ("p_reaplist not empty"));
150 p->p_treeflag &= ~P_TREE_REAPER;
151 }
152
153 static void
154 clear_orphan(struct proc *p)
155 {
156 struct proc *p1;
157
158 sx_assert(&proctree_lock, SA_XLOCKED);
159 if ((p->p_treeflag & P_TREE_ORPHANED) == 0)
160 return;
161 if ((p->p_treeflag & P_TREE_FIRST_ORPHAN) != 0) {
162 p1 = LIST_NEXT(p, p_orphan);
163 if (p1 != NULL)
164 p1->p_treeflag |= P_TREE_FIRST_ORPHAN;
165 p->p_treeflag &= ~P_TREE_FIRST_ORPHAN;
166 }
167 LIST_REMOVE(p, p_orphan);
168 p->p_treeflag &= ~P_TREE_ORPHANED;
169 }
170
171 /*
172 * exit -- death of process.
173 */
174 void
175 sys_sys_exit(struct thread *td, struct sys_exit_args *uap)
176 {
177
178 exit1(td, uap->rval, 0);
179 /* NOTREACHED */
180 }
181
182 /*
183 * Exit: deallocate address space and other resources, change proc state to
184 * zombie, and unlink proc from allproc and parent's lists. Save exit status
185 * and rusage for wait(). Check for child processes and orphan them.
186 */
187 void
188 exit1(struct thread *td, int rval, int signo)
189 {
190 struct proc *p, *nq, *q, *t;
191 struct thread *tdt;
192
193 mtx_assert(&Giant, MA_NOTOWNED);
194 KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo));
195
196 p = td->td_proc;
197 /*
198 * XXX in case we're rebooting we just let init die in order to
199 * work around an unsolved stack overflow seen very late during
200 * shutdown on sparc64 when the gmirror worker process exists.
201 */
202 if (p == initproc && rebooting == 0) {
203 printf("init died (signal %d, exit %d)\n", signo, rval);
204 panic("Going nowhere without my init!");
205 }
206
207 /*
208 * Deref SU mp, since the thread does not return to userspace.
209 */
210 if (softdep_ast_cleanup != NULL)
211 softdep_ast_cleanup();
212
213 /*
214 * MUST abort all other threads before proceeding past here.
215 */
216 PROC_LOCK(p);
217 /*
218 * First check if some other thread or external request got
219 * here before us. If so, act appropriately: exit or suspend.
220 * We must ensure that stop requests are handled before we set
221 * P_WEXIT.
222 */
223 thread_suspend_check(0);
224 while (p->p_flag & P_HADTHREADS) {
225 /*
226 * Kill off the other threads. This requires
227 * some co-operation from other parts of the kernel
228 * so it may not be instantaneous. With this state set
229 * any thread entering the kernel from userspace will
230 * thread_exit() in trap(). Any thread attempting to
231 * sleep will return immediately with EINTR or EWOULDBLOCK
232 * which will hopefully force them to back out to userland
233 * freeing resources as they go. Any thread attempting
234 * to return to userland will thread_exit() from userret().
235 * thread_exit() will unsuspend us when the last of the
236 * other threads exits.
237 * If there is already a thread singler after resumption,
238 * calling thread_single will fail; in that case, we just
239 * re-check all suspension request, the thread should
240 * either be suspended there or exit.
241 */
242 if (!thread_single(p, SINGLE_EXIT))
243 /*
244 * All other activity in this process is now
245 * stopped. Threading support has been turned
246 * off.
247 */
248 break;
249 /*
250 * Recheck for new stop or suspend requests which
251 * might appear while process lock was dropped in
252 * thread_single().
253 */
254 thread_suspend_check(0);
255 }
256 KASSERT(p->p_numthreads == 1,
257 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
258 racct_sub(p, RACCT_NTHR, 1);
259
260 /* Let event handler change exit status */
261 p->p_xexit = rval;
262 p->p_xsig = signo;
263
264 /*
265 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
266 * on our vmspace, so we should block below until they have
267 * released their reference to us. Note that if they have
268 * requested S_EXIT stops we will block here until they ack
269 * via PIOCCONT.
270 */
271 _STOPEVENT(p, S_EXIT, 0);
272
273 /*
274 * Ignore any pending request to stop due to a stop signal.
275 * Once P_WEXIT is set, future requests will be ignored as
276 * well.
277 */
278 p->p_flag &= ~P_STOPPED_SIG;
279 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped"));
280
281 /*
282 * Note that we are exiting and do another wakeup of anyone in
283 * PIOCWAIT in case they aren't listening for S_EXIT stops or
284 * decided to wait again after we told them we are exiting.
285 */
286 p->p_flag |= P_WEXIT;
287 wakeup(&p->p_stype);
288
289 /*
290 * Wait for any processes that have a hold on our vmspace to
291 * release their reference.
292 */
293 while (p->p_lock > 0)
294 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
295
296 PROC_UNLOCK(p);
297 /* Drain the limit callout while we don't have the proc locked */
298 callout_drain(&p->p_limco);
299
300 #ifdef AUDIT
301 /*
302 * The Sun BSM exit token contains two components: an exit status as
303 * passed to exit(), and a return value to indicate what sort of exit
304 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
305 * what the return value is.
306 */
307 AUDIT_ARG_EXIT(rval, 0);
308 AUDIT_SYSCALL_EXIT(0, td);
309 #endif
310
311 /* Are we a task leader with peers? */
312 if (p->p_peers != NULL && p == p->p_leader) {
313 mtx_lock(&ppeers_lock);
314 q = p->p_peers;
315 while (q != NULL) {
316 PROC_LOCK(q);
317 kern_psignal(q, SIGKILL);
318 PROC_UNLOCK(q);
319 q = q->p_peers;
320 }
321 while (p->p_peers != NULL)
322 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
323 mtx_unlock(&ppeers_lock);
324 }
325
326 /*
327 * Check if any loadable modules need anything done at process exit.
328 * E.g. SYSV IPC stuff.
329 * Event handler could change exit status.
330 * XXX what if one of these generates an error?
331 */
332 EVENTHANDLER_INVOKE(process_exit, p);
333
334 /*
335 * If parent is waiting for us to exit or exec,
336 * P_PPWAIT is set; we will wakeup the parent below.
337 */
338 PROC_LOCK(p);
339 stopprofclock(p);
340 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE);
341
342 /*
343 * Stop the real interval timer. If the handler is currently
344 * executing, prevent it from rearming itself and let it finish.
345 */
346 if (timevalisset(&p->p_realtimer.it_value) &&
347 _callout_stop_safe(&p->p_itcallout, CS_EXECUTING, NULL) == 0) {
348 timevalclear(&p->p_realtimer.it_interval);
349 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
350 KASSERT(!timevalisset(&p->p_realtimer.it_value),
351 ("realtime timer is still armed"));
352 }
353
354 PROC_UNLOCK(p);
355
356 umtx_thread_exit(td);
357
358 /*
359 * Reset any sigio structures pointing to us as a result of
360 * F_SETOWN with our pid.
361 */
362 funsetownlst(&p->p_sigiolst);
363
364 /*
365 * If this process has an nlminfo data area (for lockd), release it
366 */
367 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
368 (*nlminfo_release_p)(p);
369
370 /*
371 * Close open files and release open-file table.
372 * This may block!
373 */
374 fdescfree(td);
375
376 /*
377 * If this thread tickled GEOM, we need to wait for the giggling to
378 * stop before we return to userland
379 */
380 if (td->td_pflags & TDP_GEOM)
381 g_waitidle();
382
383 /*
384 * Remove ourself from our leader's peer list and wake our leader.
385 */
386 if (p->p_leader->p_peers != NULL) {
387 mtx_lock(&ppeers_lock);
388 if (p->p_leader->p_peers != NULL) {
389 q = p->p_leader;
390 while (q->p_peers != p)
391 q = q->p_peers;
392 q->p_peers = p->p_peers;
393 wakeup(p->p_leader);
394 }
395 mtx_unlock(&ppeers_lock);
396 }
397
398 vmspace_exit(td);
399 killjobc();
400 (void)acct_process(td);
401
402 #ifdef KTRACE
403 ktrprocexit(td);
404 #endif
405 /*
406 * Release reference to text vnode
407 */
408 if (p->p_textvp != NULL) {
409 vrele(p->p_textvp);
410 p->p_textvp = NULL;
411 }
412
413 /*
414 * Release our limits structure.
415 */
416 lim_free(p->p_limit);
417 p->p_limit = NULL;
418
419 tidhash_remove(td);
420
421 /*
422 * Remove proc from allproc queue and pidhash chain.
423 * Place onto zombproc. Unlink from parent's child list.
424 */
425 sx_xlock(&allproc_lock);
426 LIST_REMOVE(p, p_list);
427 LIST_INSERT_HEAD(&zombproc, p, p_list);
428 LIST_REMOVE(p, p_hash);
429 sx_xunlock(&allproc_lock);
430
431 /*
432 * Call machine-dependent code to release any
433 * machine-dependent resources other than the address space.
434 * The address space is released by "vmspace_exitfree(p)" in
435 * vm_waitproc().
436 */
437 cpu_exit(td);
438
439 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
440
441 /*
442 * Reparent all children processes:
443 * - traced ones to the original parent (or init if we are that parent)
444 * - the rest to init
445 */
446 sx_xlock(&proctree_lock);
447 q = LIST_FIRST(&p->p_children);
448 if (q != NULL) /* only need this if any child is S_ZOMB */
449 wakeup(q->p_reaper);
450 for (; q != NULL; q = nq) {
451 nq = LIST_NEXT(q, p_sibling);
452 PROC_LOCK(q);
453 q->p_sigparent = SIGCHLD;
454
455 if (!(q->p_flag & P_TRACED)) {
456 proc_reparent(q, q->p_reaper);
457 } else {
458 /*
459 * Traced processes are killed since their existence
460 * means someone is screwing up.
461 */
462 t = proc_realparent(q);
463 if (t == p) {
464 proc_reparent(q, q->p_reaper);
465 } else {
466 PROC_LOCK(t);
467 proc_reparent(q, t);
468 PROC_UNLOCK(t);
469 }
470 /*
471 * Since q was found on our children list, the
472 * proc_reparent() call moved q to the orphan
473 * list due to present P_TRACED flag. Clear
474 * orphan link for q now while q is locked.
475 */
476 clear_orphan(q);
477 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
478 FOREACH_THREAD_IN_PROC(q, tdt)
479 tdt->td_dbgflags &= ~TDB_SUSPEND;
480 kern_psignal(q, SIGKILL);
481 }
482 PROC_UNLOCK(q);
483 }
484
485 /*
486 * Also get rid of our orphans.
487 */
488 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) {
489 PROC_LOCK(q);
490 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid,
491 q->p_pid);
492 clear_orphan(q);
493 PROC_UNLOCK(q);
494 }
495
496 /* Save exit status. */
497 PROC_LOCK(p);
498 p->p_xthread = td;
499
500 /* Tell the prison that we are gone. */
501 prison_proc_free(p->p_ucred->cr_prison);
502
503 #ifdef KDTRACE_HOOKS
504 /*
505 * Tell the DTrace fasttrap provider about the exit if it
506 * has declared an interest.
507 */
508 if (dtrace_fasttrap_exit)
509 dtrace_fasttrap_exit(p);
510 #endif
511
512 /*
513 * Notify interested parties of our demise.
514 */
515 KNOTE_LOCKED(p->p_klist, NOTE_EXIT);
516
517 #ifdef KDTRACE_HOOKS
518 int reason = CLD_EXITED;
519 if (WCOREDUMP(signo))
520 reason = CLD_DUMPED;
521 else if (WIFSIGNALED(signo))
522 reason = CLD_KILLED;
523 SDT_PROBE1(proc, , , exit, reason);
524 #endif
525
526 /*
527 * If this is a process with a descriptor, we may not need to deliver
528 * a signal to the parent. proctree_lock is held over
529 * procdesc_exit() to serialize concurrent calls to close() and
530 * exit().
531 */
532 if (p->p_procdesc == NULL || procdesc_exit(p)) {
533 /*
534 * Notify parent that we're gone. If parent has the
535 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN,
536 * notify process 1 instead (and hope it will handle this
537 * situation).
538 */
539 PROC_LOCK(p->p_pptr);
540 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
541 if (p->p_pptr->p_sigacts->ps_flag &
542 (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
543 struct proc *pp;
544
545 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
546 pp = p->p_pptr;
547 PROC_UNLOCK(pp);
548 proc_reparent(p, p->p_reaper);
549 p->p_sigparent = SIGCHLD;
550 PROC_LOCK(p->p_pptr);
551
552 /*
553 * Notify parent, so in case he was wait(2)ing or
554 * executing waitpid(2) with our pid, he will
555 * continue.
556 */
557 wakeup(pp);
558 } else
559 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
560
561 if (p->p_pptr == p->p_reaper || p->p_pptr == initproc)
562 childproc_exited(p);
563 else if (p->p_sigparent != 0) {
564 if (p->p_sigparent == SIGCHLD)
565 childproc_exited(p);
566 else /* LINUX thread */
567 kern_psignal(p->p_pptr, p->p_sigparent);
568 }
569 } else
570 PROC_LOCK(p->p_pptr);
571 sx_xunlock(&proctree_lock);
572
573 /*
574 * The state PRS_ZOMBIE prevents other proesses from sending
575 * signal to the process, to avoid memory leak, we free memory
576 * for signal queue at the time when the state is set.
577 */
578 sigqueue_flush(&p->p_sigqueue);
579 sigqueue_flush(&td->td_sigqueue);
580
581 /*
582 * We have to wait until after acquiring all locks before
583 * changing p_state. We need to avoid all possible context
584 * switches (including ones from blocking on a mutex) while
585 * marked as a zombie. We also have to set the zombie state
586 * before we release the parent process' proc lock to avoid
587 * a lost wakeup. So, we first call wakeup, then we grab the
588 * sched lock, update the state, and release the parent process'
589 * proc lock.
590 */
591 wakeup(p->p_pptr);
592 cv_broadcast(&p->p_pwait);
593 sched_exit(p->p_pptr, td);
594 PROC_SLOCK(p);
595 p->p_state = PRS_ZOMBIE;
596 PROC_UNLOCK(p->p_pptr);
597
598 /*
599 * Save our children's rusage information in our exit rusage.
600 */
601 PROC_STATLOCK(p);
602 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
603 PROC_STATUNLOCK(p);
604
605 /*
606 * Make sure the scheduler takes this thread out of its tables etc.
607 * This will also release this thread's reference to the ucred.
608 * Other thread parts to release include pcb bits and such.
609 */
610 thread_exit();
611 }
612
613
614 #ifndef _SYS_SYSPROTO_H_
615 struct abort2_args {
616 char *why;
617 int nargs;
618 void **args;
619 };
620 #endif
621
622 int
623 sys_abort2(struct thread *td, struct abort2_args *uap)
624 {
625 struct proc *p = td->td_proc;
626 struct sbuf *sb;
627 void *uargs[16];
628 int error, i, sig;
629
630 /*
631 * Do it right now so we can log either proper call of abort2(), or
632 * note, that invalid argument was passed. 512 is big enough to
633 * handle 16 arguments' descriptions with additional comments.
634 */
635 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
636 sbuf_clear(sb);
637 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
638 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
639 /*
640 * Since we can't return from abort2(), send SIGKILL in cases, where
641 * abort2() was called improperly
642 */
643 sig = SIGKILL;
644 /* Prevent from DoSes from user-space. */
645 if (uap->nargs < 0 || uap->nargs > 16)
646 goto out;
647 if (uap->nargs > 0) {
648 if (uap->args == NULL)
649 goto out;
650 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
651 if (error != 0)
652 goto out;
653 }
654 /*
655 * Limit size of 'reason' string to 128. Will fit even when
656 * maximal number of arguments was chosen to be logged.
657 */
658 if (uap->why != NULL) {
659 error = sbuf_copyin(sb, uap->why, 128);
660 if (error < 0)
661 goto out;
662 } else {
663 sbuf_printf(sb, "(null)");
664 }
665 if (uap->nargs > 0) {
666 sbuf_printf(sb, "(");
667 for (i = 0;i < uap->nargs; i++)
668 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
669 sbuf_printf(sb, ")");
670 }
671 /*
672 * Final stage: arguments were proper, string has been
673 * successfully copied from userspace, and copying pointers
674 * from user-space succeed.
675 */
676 sig = SIGABRT;
677 out:
678 if (sig == SIGKILL) {
679 sbuf_trim(sb);
680 sbuf_printf(sb, " (Reason text inaccessible)");
681 }
682 sbuf_cat(sb, "\n");
683 sbuf_finish(sb);
684 log(LOG_INFO, "%s", sbuf_data(sb));
685 sbuf_delete(sb);
686 exit1(td, 0, sig);
687 return (0);
688 }
689
690
691 #ifdef COMPAT_43
692 /*
693 * The dirty work is handled by kern_wait().
694 */
695 int
696 owait(struct thread *td, struct owait_args *uap __unused)
697 {
698 int error, status;
699
700 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
701 if (error == 0)
702 td->td_retval[1] = status;
703 return (error);
704 }
705 #endif /* COMPAT_43 */
706
707 /*
708 * The dirty work is handled by kern_wait().
709 */
710 int
711 sys_wait4(struct thread *td, struct wait4_args *uap)
712 {
713 struct rusage ru, *rup;
714 int error, status;
715
716 if (uap->rusage != NULL)
717 rup = &ru;
718 else
719 rup = NULL;
720 error = kern_wait(td, uap->pid, &status, uap->options, rup);
721 if (uap->status != NULL && error == 0)
722 error = copyout(&status, uap->status, sizeof(status));
723 if (uap->rusage != NULL && error == 0)
724 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
725 return (error);
726 }
727
728 int
729 sys_wait6(struct thread *td, struct wait6_args *uap)
730 {
731 struct __wrusage wru, *wrup;
732 siginfo_t si, *sip;
733 idtype_t idtype;
734 id_t id;
735 int error, status;
736
737 idtype = uap->idtype;
738 id = uap->id;
739
740 if (uap->wrusage != NULL)
741 wrup = &wru;
742 else
743 wrup = NULL;
744
745 if (uap->info != NULL) {
746 sip = &si;
747 bzero(sip, sizeof(*sip));
748 } else
749 sip = NULL;
750
751 /*
752 * We expect all callers of wait6() to know about WEXITED and
753 * WTRAPPED.
754 */
755 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip);
756
757 if (uap->status != NULL && error == 0)
758 error = copyout(&status, uap->status, sizeof(status));
759 if (uap->wrusage != NULL && error == 0)
760 error = copyout(&wru, uap->wrusage, sizeof(wru));
761 if (uap->info != NULL && error == 0)
762 error = copyout(&si, uap->info, sizeof(si));
763 return (error);
764 }
765
766 /*
767 * Reap the remains of a zombie process and optionally return status and
768 * rusage. Asserts and will release both the proctree_lock and the process
769 * lock as part of its work.
770 */
771 void
772 proc_reap(struct thread *td, struct proc *p, int *status, int options)
773 {
774 struct proc *q, *t;
775
776 sx_assert(&proctree_lock, SA_XLOCKED);
777 PROC_LOCK_ASSERT(p, MA_OWNED);
778 PROC_SLOCK_ASSERT(p, MA_OWNED);
779 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
780
781 q = td->td_proc;
782
783 PROC_SUNLOCK(p);
784 if (status)
785 *status = KW_EXITCODE(p->p_xexit, p->p_xsig);
786 if (options & WNOWAIT) {
787 /*
788 * Only poll, returning the status. Caller does not wish to
789 * release the proc struct just yet.
790 */
791 PROC_UNLOCK(p);
792 sx_xunlock(&proctree_lock);
793 return;
794 }
795
796 PROC_LOCK(q);
797 sigqueue_take(p->p_ksi);
798 PROC_UNLOCK(q);
799
800 /*
801 * If we got the child via a ptrace 'attach', we need to give it back
802 * to the old parent.
803 */
804 if (p->p_oppid != 0 && p->p_oppid != p->p_pptr->p_pid) {
805 PROC_UNLOCK(p);
806 t = proc_realparent(p);
807 PROC_LOCK(t);
808 PROC_LOCK(p);
809 CTR2(KTR_PTRACE,
810 "wait: traced child %d moved back to parent %d", p->p_pid,
811 t->p_pid);
812 proc_reparent(p, t);
813 p->p_oppid = 0;
814 PROC_UNLOCK(p);
815 pksignal(t, SIGCHLD, p->p_ksi);
816 wakeup(t);
817 cv_broadcast(&p->p_pwait);
818 PROC_UNLOCK(t);
819 sx_xunlock(&proctree_lock);
820 return;
821 }
822 p->p_oppid = 0;
823 PROC_UNLOCK(p);
824
825 /*
826 * Remove other references to this process to ensure we have an
827 * exclusive reference.
828 */
829 sx_xlock(&allproc_lock);
830 LIST_REMOVE(p, p_list); /* off zombproc */
831 sx_xunlock(&allproc_lock);
832 LIST_REMOVE(p, p_sibling);
833 reaper_abandon_children(p, true);
834 LIST_REMOVE(p, p_reapsibling);
835 PROC_LOCK(p);
836 clear_orphan(p);
837 PROC_UNLOCK(p);
838 leavepgrp(p);
839 if (p->p_procdesc != NULL)
840 procdesc_reap(p);
841 sx_xunlock(&proctree_lock);
842
843 PROC_LOCK(p);
844 knlist_detach(p->p_klist);
845 p->p_klist = NULL;
846 PROC_UNLOCK(p);
847
848 /*
849 * Removal from allproc list and process group list paired with
850 * PROC_LOCK which was executed during that time should guarantee
851 * nothing can reach this process anymore. As such further locking
852 * is unnecessary.
853 */
854 p->p_xexit = p->p_xsig = 0; /* XXX: why? */
855
856 PROC_LOCK(q);
857 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
858 PROC_UNLOCK(q);
859
860 /*
861 * Decrement the count of procs running with this uid.
862 */
863 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
864
865 /*
866 * Destroy resource accounting information associated with the process.
867 */
868 #ifdef RACCT
869 if (racct_enable) {
870 PROC_LOCK(p);
871 racct_sub(p, RACCT_NPROC, 1);
872 PROC_UNLOCK(p);
873 }
874 #endif
875 racct_proc_exit(p);
876
877 /*
878 * Free credentials, arguments, and sigacts.
879 */
880 crfree(p->p_ucred);
881 proc_set_cred(p, NULL);
882 pargs_drop(p->p_args);
883 p->p_args = NULL;
884 sigacts_free(p->p_sigacts);
885 p->p_sigacts = NULL;
886
887 /*
888 * Do any thread-system specific cleanups.
889 */
890 thread_wait(p);
891
892 /*
893 * Give vm and machine-dependent layer a chance to free anything that
894 * cpu_exit couldn't release while still running in process context.
895 */
896 vm_waitproc(p);
897 #ifdef MAC
898 mac_proc_destroy(p);
899 #endif
900 /*
901 * Free any domain policy that's still hiding around.
902 */
903 vm_domain_policy_cleanup(&p->p_vm_dom_policy);
904
905 KASSERT(FIRST_THREAD_IN_PROC(p),
906 ("proc_reap: no residual thread!"));
907 uma_zfree(proc_zone, p);
908 atomic_add_int(&nprocs, -1);
909 }
910
911 static int
912 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
913 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo,
914 int check_only)
915 {
916 struct rusage *rup;
917
918 sx_assert(&proctree_lock, SA_XLOCKED);
919
920 PROC_LOCK(p);
921
922 switch (idtype) {
923 case P_ALL:
924 if (p->p_procdesc != NULL) {
925 PROC_UNLOCK(p);
926 return (0);
927 }
928 break;
929 case P_PID:
930 if (p->p_pid != (pid_t)id) {
931 PROC_UNLOCK(p);
932 return (0);
933 }
934 break;
935 case P_PGID:
936 if (p->p_pgid != (pid_t)id) {
937 PROC_UNLOCK(p);
938 return (0);
939 }
940 break;
941 case P_SID:
942 if (p->p_session->s_sid != (pid_t)id) {
943 PROC_UNLOCK(p);
944 return (0);
945 }
946 break;
947 case P_UID:
948 if (p->p_ucred->cr_uid != (uid_t)id) {
949 PROC_UNLOCK(p);
950 return (0);
951 }
952 break;
953 case P_GID:
954 if (p->p_ucred->cr_gid != (gid_t)id) {
955 PROC_UNLOCK(p);
956 return (0);
957 }
958 break;
959 case P_JAILID:
960 if (p->p_ucred->cr_prison->pr_id != (int)id) {
961 PROC_UNLOCK(p);
962 return (0);
963 }
964 break;
965 /*
966 * It seems that the thread structures get zeroed out
967 * at process exit. This makes it impossible to
968 * support P_SETID, P_CID or P_CPUID.
969 */
970 default:
971 PROC_UNLOCK(p);
972 return (0);
973 }
974
975 if (p_canwait(td, p)) {
976 PROC_UNLOCK(p);
977 return (0);
978 }
979
980 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) {
981 PROC_UNLOCK(p);
982 return (0);
983 }
984
985 /*
986 * This special case handles a kthread spawned by linux_clone
987 * (see linux_misc.c). The linux_wait4 and linux_waitpid
988 * functions need to be able to distinguish between waiting
989 * on a process and waiting on a thread. It is a thread if
990 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
991 * signifies we want to wait for threads and not processes.
992 */
993 if ((p->p_sigparent != SIGCHLD) ^
994 ((options & WLINUXCLONE) != 0)) {
995 PROC_UNLOCK(p);
996 return (0);
997 }
998
999 if (siginfo != NULL) {
1000 bzero(siginfo, sizeof(*siginfo));
1001 siginfo->si_errno = 0;
1002
1003 /*
1004 * SUSv4 requires that the si_signo value is always
1005 * SIGCHLD. Obey it despite the rfork(2) interface
1006 * allows to request other signal for child exit
1007 * notification.
1008 */
1009 siginfo->si_signo = SIGCHLD;
1010
1011 /*
1012 * This is still a rough estimate. We will fix the
1013 * cases TRAPPED, STOPPED, and CONTINUED later.
1014 */
1015 if (WCOREDUMP(p->p_xsig)) {
1016 siginfo->si_code = CLD_DUMPED;
1017 siginfo->si_status = WTERMSIG(p->p_xsig);
1018 } else if (WIFSIGNALED(p->p_xsig)) {
1019 siginfo->si_code = CLD_KILLED;
1020 siginfo->si_status = WTERMSIG(p->p_xsig);
1021 } else {
1022 siginfo->si_code = CLD_EXITED;
1023 siginfo->si_status = p->p_xexit;
1024 }
1025
1026 siginfo->si_pid = p->p_pid;
1027 siginfo->si_uid = p->p_ucred->cr_uid;
1028
1029 /*
1030 * The si_addr field would be useful additional
1031 * detail, but apparently the PC value may be lost
1032 * when we reach this point. bzero() above sets
1033 * siginfo->si_addr to NULL.
1034 */
1035 }
1036
1037 /*
1038 * There should be no reason to limit resources usage info to
1039 * exited processes only. A snapshot about any resources used
1040 * by a stopped process may be exactly what is needed.
1041 */
1042 if (wrusage != NULL) {
1043 rup = &wrusage->wru_self;
1044 *rup = p->p_ru;
1045 PROC_STATLOCK(p);
1046 calcru(p, &rup->ru_utime, &rup->ru_stime);
1047 PROC_STATUNLOCK(p);
1048
1049 rup = &wrusage->wru_children;
1050 *rup = p->p_stats->p_cru;
1051 calccru(p, &rup->ru_utime, &rup->ru_stime);
1052 }
1053
1054 if (p->p_state == PRS_ZOMBIE && !check_only) {
1055 PROC_SLOCK(p);
1056 proc_reap(td, p, status, options);
1057 return (-1);
1058 }
1059 PROC_UNLOCK(p);
1060 return (1);
1061 }
1062
1063 int
1064 kern_wait(struct thread *td, pid_t pid, int *status, int options,
1065 struct rusage *rusage)
1066 {
1067 struct __wrusage wru, *wrup;
1068 idtype_t idtype;
1069 id_t id;
1070 int ret;
1071
1072 /*
1073 * Translate the special pid values into the (idtype, pid)
1074 * pair for kern_wait6. The WAIT_MYPGRP case is handled by
1075 * kern_wait6() on its own.
1076 */
1077 if (pid == WAIT_ANY) {
1078 idtype = P_ALL;
1079 id = 0;
1080 } else if (pid < 0) {
1081 idtype = P_PGID;
1082 id = (id_t)-pid;
1083 } else {
1084 idtype = P_PID;
1085 id = (id_t)pid;
1086 }
1087
1088 if (rusage != NULL)
1089 wrup = &wru;
1090 else
1091 wrup = NULL;
1092
1093 /*
1094 * For backward compatibility we implicitly add flags WEXITED
1095 * and WTRAPPED here.
1096 */
1097 options |= WEXITED | WTRAPPED;
1098 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL);
1099 if (rusage != NULL)
1100 *rusage = wru.wru_self;
1101 return (ret);
1102 }
1103
1104 int
1105 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status,
1106 int options, struct __wrusage *wrusage, siginfo_t *siginfo)
1107 {
1108 struct proc *p, *q;
1109 pid_t pid;
1110 int error, nfound, ret;
1111
1112 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */
1113 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */
1114 AUDIT_ARG_VALUE(options);
1115
1116 q = td->td_proc;
1117
1118 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) {
1119 PROC_LOCK(q);
1120 id = (id_t)q->p_pgid;
1121 PROC_UNLOCK(q);
1122 idtype = P_PGID;
1123 }
1124
1125 /* If we don't know the option, just return. */
1126 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT |
1127 WEXITED | WTRAPPED | WLINUXCLONE)) != 0)
1128 return (EINVAL);
1129 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) {
1130 /*
1131 * We will be unable to find any matching processes,
1132 * because there are no known events to look for.
1133 * Prefer to return error instead of blocking
1134 * indefinitely.
1135 */
1136 return (EINVAL);
1137 }
1138
1139 loop:
1140 if (q->p_flag & P_STATCHILD) {
1141 PROC_LOCK(q);
1142 q->p_flag &= ~P_STATCHILD;
1143 PROC_UNLOCK(q);
1144 }
1145 nfound = 0;
1146 sx_xlock(&proctree_lock);
1147 LIST_FOREACH(p, &q->p_children, p_sibling) {
1148 pid = p->p_pid;
1149 ret = proc_to_reap(td, p, idtype, id, status, options,
1150 wrusage, siginfo, 0);
1151 if (ret == 0)
1152 continue;
1153 else if (ret == 1)
1154 nfound++;
1155 else {
1156 td->td_retval[0] = pid;
1157 return (0);
1158 }
1159
1160 PROC_LOCK(p);
1161 PROC_SLOCK(p);
1162
1163 if ((options & WTRAPPED) != 0 &&
1164 (p->p_flag & P_TRACED) != 0 &&
1165 (p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) != 0 &&
1166 (p->p_suspcount == p->p_numthreads) &&
1167 ((p->p_flag & P_WAITED) == 0)) {
1168 PROC_SUNLOCK(p);
1169 if ((options & WNOWAIT) == 0)
1170 p->p_flag |= P_WAITED;
1171 sx_xunlock(&proctree_lock);
1172
1173 if (status != NULL)
1174 *status = W_STOPCODE(p->p_xsig);
1175 if (siginfo != NULL) {
1176 siginfo->si_status = p->p_xsig;
1177 siginfo->si_code = CLD_TRAPPED;
1178 }
1179 if ((options & WNOWAIT) == 0) {
1180 PROC_LOCK(q);
1181 sigqueue_take(p->p_ksi);
1182 PROC_UNLOCK(q);
1183 }
1184
1185 CTR4(KTR_PTRACE,
1186 "wait: returning trapped pid %d status %#x (xstat %d) xthread %d",
1187 p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig,
1188 p->p_xthread != NULL ? p->p_xthread->td_tid : -1);
1189 PROC_UNLOCK(p);
1190 td->td_retval[0] = pid;
1191 return (0);
1192 }
1193 if ((options & WUNTRACED) != 0 &&
1194 (p->p_flag & P_STOPPED_SIG) != 0 &&
1195 (p->p_suspcount == p->p_numthreads) &&
1196 ((p->p_flag & P_WAITED) == 0)) {
1197 PROC_SUNLOCK(p);
1198 if ((options & WNOWAIT) == 0)
1199 p->p_flag |= P_WAITED;
1200 sx_xunlock(&proctree_lock);
1201
1202 if (status != NULL)
1203 *status = W_STOPCODE(p->p_xsig);
1204 if (siginfo != NULL) {
1205 siginfo->si_status = p->p_xsig;
1206 siginfo->si_code = CLD_STOPPED;
1207 }
1208 if ((options & WNOWAIT) == 0) {
1209 PROC_LOCK(q);
1210 sigqueue_take(p->p_ksi);
1211 PROC_UNLOCK(q);
1212 }
1213
1214 PROC_UNLOCK(p);
1215 td->td_retval[0] = pid;
1216 return (0);
1217 }
1218 PROC_SUNLOCK(p);
1219 if ((options & WCONTINUED) != 0 &&
1220 (p->p_flag & P_CONTINUED) != 0) {
1221 sx_xunlock(&proctree_lock);
1222 if ((options & WNOWAIT) == 0) {
1223 p->p_flag &= ~P_CONTINUED;
1224 PROC_LOCK(q);
1225 sigqueue_take(p->p_ksi);
1226 PROC_UNLOCK(q);
1227 }
1228 PROC_UNLOCK(p);
1229
1230 if (status != NULL)
1231 *status = SIGCONT;
1232 if (siginfo != NULL) {
1233 siginfo->si_status = SIGCONT;
1234 siginfo->si_code = CLD_CONTINUED;
1235 }
1236 td->td_retval[0] = pid;
1237 return (0);
1238 }
1239 PROC_UNLOCK(p);
1240 }
1241
1242 /*
1243 * Look in the orphans list too, to allow the parent to
1244 * collect it's child exit status even if child is being
1245 * debugged.
1246 *
1247 * Debugger detaches from the parent upon successful
1248 * switch-over from parent to child. At this point due to
1249 * re-parenting the parent loses the child to debugger and a
1250 * wait4(2) call would report that it has no children to wait
1251 * for. By maintaining a list of orphans we allow the parent
1252 * to successfully wait until the child becomes a zombie.
1253 */
1254 if (nfound == 0) {
1255 LIST_FOREACH(p, &q->p_orphans, p_orphan) {
1256 ret = proc_to_reap(td, p, idtype, id, NULL, options,
1257 NULL, NULL, 1);
1258 if (ret != 0) {
1259 KASSERT(ret != -1, ("reaped an orphan (pid %d)",
1260 (int)td->td_retval[0]));
1261 nfound++;
1262 break;
1263 }
1264 }
1265 }
1266 if (nfound == 0) {
1267 sx_xunlock(&proctree_lock);
1268 return (ECHILD);
1269 }
1270 if (options & WNOHANG) {
1271 sx_xunlock(&proctree_lock);
1272 td->td_retval[0] = 0;
1273 return (0);
1274 }
1275 PROC_LOCK(q);
1276 sx_xunlock(&proctree_lock);
1277 if (q->p_flag & P_STATCHILD) {
1278 q->p_flag &= ~P_STATCHILD;
1279 error = 0;
1280 } else
1281 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
1282 PROC_UNLOCK(q);
1283 if (error)
1284 return (error);
1285 goto loop;
1286 }
1287
1288 /*
1289 * Make process 'parent' the new parent of process 'child'.
1290 * Must be called with an exclusive hold of proctree lock.
1291 */
1292 void
1293 proc_reparent(struct proc *child, struct proc *parent)
1294 {
1295
1296 sx_assert(&proctree_lock, SX_XLOCKED);
1297 PROC_LOCK_ASSERT(child, MA_OWNED);
1298 if (child->p_pptr == parent)
1299 return;
1300
1301 PROC_LOCK(child->p_pptr);
1302 sigqueue_take(child->p_ksi);
1303 PROC_UNLOCK(child->p_pptr);
1304 LIST_REMOVE(child, p_sibling);
1305 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1306
1307 clear_orphan(child);
1308 if (child->p_flag & P_TRACED) {
1309 if (LIST_EMPTY(&child->p_pptr->p_orphans)) {
1310 child->p_treeflag |= P_TREE_FIRST_ORPHAN;
1311 LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child,
1312 p_orphan);
1313 } else {
1314 LIST_INSERT_AFTER(LIST_FIRST(&child->p_pptr->p_orphans),
1315 child, p_orphan);
1316 }
1317 child->p_treeflag |= P_TREE_ORPHANED;
1318 }
1319
1320 child->p_pptr = parent;
1321 }
Cache object: 135a48911fb5d1707e0a88f1ecf4608a
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