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: releng/12.0/sys/kern/kern_exit.c 332740 2018-04-18 21:31:13Z kib $");
41
42 #include "opt_ktrace.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/sysproto.h>
47 #include <sys/capsicum.h>
48 #include <sys/eventhandler.h>
49 #include <sys/kernel.h>
50 #include <sys/malloc.h>
51 #include <sys/lock.h>
52 #include <sys/mutex.h>
53 #include <sys/proc.h>
54 #include <sys/procdesc.h>
55 #include <sys/pioctl.h>
56 #include <sys/jail.h>
57 #include <sys/tty.h>
58 #include <sys/wait.h>
59 #include <sys/vmmeter.h>
60 #include <sys/vnode.h>
61 #include <sys/racct.h>
62 #include <sys/resourcevar.h>
63 #include <sys/sbuf.h>
64 #include <sys/signalvar.h>
65 #include <sys/sched.h>
66 #include <sys/sx.h>
67 #include <sys/syscallsubr.h>
68 #include <sys/syslog.h>
69 #include <sys/ptrace.h>
70 #include <sys/acct.h> /* for acct_process() function prototype */
71 #include <sys/filedesc.h>
72 #include <sys/sdt.h>
73 #include <sys/shm.h>
74 #include <sys/sem.h>
75 #include <sys/umtx.h>
76 #ifdef KTRACE
77 #include <sys/ktrace.h>
78 #endif
79
80 #include <security/audit/audit.h>
81 #include <security/mac/mac_framework.h>
82
83 #include <vm/vm.h>
84 #include <vm/vm_extern.h>
85 #include <vm/vm_param.h>
86 #include <vm/pmap.h>
87 #include <vm/vm_map.h>
88 #include <vm/vm_page.h>
89 #include <vm/uma.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 EVENTHANDLER_LIST_DECLARE(process_exit);
103
104 struct proc *
105 proc_realparent(struct proc *child)
106 {
107 struct proc *p, *parent;
108
109 sx_assert(&proctree_lock, SX_LOCKED);
110 if ((child->p_treeflag & P_TREE_ORPHANED) == 0) {
111 if (child->p_oppid == 0 ||
112 child->p_pptr->p_pid == child->p_oppid)
113 parent = child->p_pptr;
114 else
115 parent = initproc;
116 return (parent);
117 }
118 for (p = child; (p->p_treeflag & P_TREE_FIRST_ORPHAN) == 0;) {
119 /* Cannot use LIST_PREV(), since the list head is not known. */
120 p = __containerof(p->p_orphan.le_prev, struct proc,
121 p_orphan.le_next);
122 KASSERT((p->p_treeflag & P_TREE_ORPHANED) != 0,
123 ("missing P_ORPHAN %p", p));
124 }
125 parent = __containerof(p->p_orphan.le_prev, struct proc,
126 p_orphans.lh_first);
127 return (parent);
128 }
129
130 void
131 reaper_abandon_children(struct proc *p, bool exiting)
132 {
133 struct proc *p1, *p2, *ptmp;
134
135 sx_assert(&proctree_lock, SX_LOCKED);
136 KASSERT(p != initproc, ("reaper_abandon_children for initproc"));
137 if ((p->p_treeflag & P_TREE_REAPER) == 0)
138 return;
139 p1 = p->p_reaper;
140 LIST_FOREACH_SAFE(p2, &p->p_reaplist, p_reapsibling, ptmp) {
141 LIST_REMOVE(p2, p_reapsibling);
142 p2->p_reaper = p1;
143 p2->p_reapsubtree = p->p_reapsubtree;
144 LIST_INSERT_HEAD(&p1->p_reaplist, p2, p_reapsibling);
145 if (exiting && p2->p_pptr == p) {
146 PROC_LOCK(p2);
147 proc_reparent(p2, p1);
148 PROC_UNLOCK(p2);
149 }
150 }
151 KASSERT(LIST_EMPTY(&p->p_reaplist), ("p_reaplist not empty"));
152 p->p_treeflag &= ~P_TREE_REAPER;
153 }
154
155 static void
156 clear_orphan(struct proc *p)
157 {
158 struct proc *p1;
159
160 sx_assert(&proctree_lock, SA_XLOCKED);
161 if ((p->p_treeflag & P_TREE_ORPHANED) == 0)
162 return;
163 if ((p->p_treeflag & P_TREE_FIRST_ORPHAN) != 0) {
164 p1 = LIST_NEXT(p, p_orphan);
165 if (p1 != NULL)
166 p1->p_treeflag |= P_TREE_FIRST_ORPHAN;
167 p->p_treeflag &= ~P_TREE_FIRST_ORPHAN;
168 }
169 LIST_REMOVE(p, p_orphan);
170 p->p_treeflag &= ~P_TREE_ORPHANED;
171 }
172
173 /*
174 * exit -- death of process.
175 */
176 void
177 sys_sys_exit(struct thread *td, struct sys_exit_args *uap)
178 {
179
180 exit1(td, uap->rval, 0);
181 /* NOTREACHED */
182 }
183
184 /*
185 * Exit: deallocate address space and other resources, change proc state to
186 * zombie, and unlink proc from allproc and parent's lists. Save exit status
187 * and rusage for wait(). Check for child processes and orphan them.
188 */
189 void
190 exit1(struct thread *td, int rval, int signo)
191 {
192 struct proc *p, *nq, *q, *t;
193 struct thread *tdt;
194 ksiginfo_t *ksi, *ksi1;
195 int signal_parent;
196
197 mtx_assert(&Giant, MA_NOTOWNED);
198 KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo));
199
200 p = td->td_proc;
201 /*
202 * XXX in case we're rebooting we just let init die in order to
203 * work around an unsolved stack overflow seen very late during
204 * shutdown on sparc64 when the gmirror worker process exists.
205 */
206 if (p == initproc && rebooting == 0) {
207 printf("init died (signal %d, exit %d)\n", signo, rval);
208 panic("Going nowhere without my init!");
209 }
210
211 /*
212 * Deref SU mp, since the thread does not return to userspace.
213 */
214 td_softdep_cleanup(td);
215
216 /*
217 * MUST abort all other threads before proceeding past here.
218 */
219 PROC_LOCK(p);
220 /*
221 * First check if some other thread or external request got
222 * here before us. If so, act appropriately: exit or suspend.
223 * We must ensure that stop requests are handled before we set
224 * P_WEXIT.
225 */
226 thread_suspend_check(0);
227 while (p->p_flag & P_HADTHREADS) {
228 /*
229 * Kill off the other threads. This requires
230 * some co-operation from other parts of the kernel
231 * so it may not be instantaneous. With this state set
232 * any thread entering the kernel from userspace will
233 * thread_exit() in trap(). Any thread attempting to
234 * sleep will return immediately with EINTR or EWOULDBLOCK
235 * which will hopefully force them to back out to userland
236 * freeing resources as they go. Any thread attempting
237 * to return to userland will thread_exit() from userret().
238 * thread_exit() will unsuspend us when the last of the
239 * other threads exits.
240 * If there is already a thread singler after resumption,
241 * calling thread_single will fail; in that case, we just
242 * re-check all suspension request, the thread should
243 * either be suspended there or exit.
244 */
245 if (!thread_single(p, SINGLE_EXIT))
246 /*
247 * All other activity in this process is now
248 * stopped. Threading support has been turned
249 * off.
250 */
251 break;
252 /*
253 * Recheck for new stop or suspend requests which
254 * might appear while process lock was dropped in
255 * thread_single().
256 */
257 thread_suspend_check(0);
258 }
259 KASSERT(p->p_numthreads == 1,
260 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
261 racct_sub(p, RACCT_NTHR, 1);
262
263 /* Let event handler change exit status */
264 p->p_xexit = rval;
265 p->p_xsig = signo;
266
267 /*
268 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
269 * on our vmspace, so we should block below until they have
270 * released their reference to us. Note that if they have
271 * requested S_EXIT stops we will block here until they ack
272 * via PIOCCONT.
273 */
274 _STOPEVENT(p, S_EXIT, 0);
275
276 /*
277 * Ignore any pending request to stop due to a stop signal.
278 * Once P_WEXIT is set, future requests will be ignored as
279 * well.
280 */
281 p->p_flag &= ~P_STOPPED_SIG;
282 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped"));
283
284 /*
285 * Note that we are exiting and do another wakeup of anyone in
286 * PIOCWAIT in case they aren't listening for S_EXIT stops or
287 * decided to wait again after we told them we are exiting.
288 */
289 p->p_flag |= P_WEXIT;
290 wakeup(&p->p_stype);
291
292 /*
293 * Wait for any processes that have a hold on our vmspace to
294 * release their reference.
295 */
296 while (p->p_lock > 0)
297 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
298
299 PROC_UNLOCK(p);
300 /* Drain the limit callout while we don't have the proc locked */
301 callout_drain(&p->p_limco);
302
303 #ifdef AUDIT
304 /*
305 * The Sun BSM exit token contains two components: an exit status as
306 * passed to exit(), and a return value to indicate what sort of exit
307 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
308 * what the return value is.
309 */
310 AUDIT_ARG_EXIT(rval, 0);
311 AUDIT_SYSCALL_EXIT(0, td);
312 #endif
313
314 /* Are we a task leader with peers? */
315 if (p->p_peers != NULL && p == p->p_leader) {
316 mtx_lock(&ppeers_lock);
317 q = p->p_peers;
318 while (q != NULL) {
319 PROC_LOCK(q);
320 kern_psignal(q, SIGKILL);
321 PROC_UNLOCK(q);
322 q = q->p_peers;
323 }
324 while (p->p_peers != NULL)
325 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
326 mtx_unlock(&ppeers_lock);
327 }
328
329 /*
330 * Check if any loadable modules need anything done at process exit.
331 * E.g. SYSV IPC stuff.
332 * Event handler could change exit status.
333 * XXX what if one of these generates an error?
334 */
335 EVENTHANDLER_DIRECT_INVOKE(process_exit, p);
336
337 /*
338 * If parent is waiting for us to exit or exec,
339 * P_PPWAIT is set; we will wakeup the parent below.
340 */
341 PROC_LOCK(p);
342 stopprofclock(p);
343 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE);
344 p->p_ptevents = 0;
345
346 /*
347 * Stop the real interval timer. If the handler is currently
348 * executing, prevent it from rearming itself and let it finish.
349 */
350 if (timevalisset(&p->p_realtimer.it_value) &&
351 _callout_stop_safe(&p->p_itcallout, CS_EXECUTING, NULL) == 0) {
352 timevalclear(&p->p_realtimer.it_interval);
353 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
354 KASSERT(!timevalisset(&p->p_realtimer.it_value),
355 ("realtime timer is still armed"));
356 }
357
358 PROC_UNLOCK(p);
359
360 umtx_thread_exit(td);
361
362 /*
363 * Reset any sigio structures pointing to us as a result of
364 * F_SETOWN with our pid.
365 */
366 funsetownlst(&p->p_sigiolst);
367
368 /*
369 * If this process has an nlminfo data area (for lockd), release it
370 */
371 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
372 (*nlminfo_release_p)(p);
373
374 /*
375 * Close open files and release open-file table.
376 * This may block!
377 */
378 fdescfree(td);
379
380 /*
381 * If this thread tickled GEOM, we need to wait for the giggling to
382 * stop before we return to userland
383 */
384 if (td->td_pflags & TDP_GEOM)
385 g_waitidle();
386
387 /*
388 * Remove ourself from our leader's peer list and wake our leader.
389 */
390 if (p->p_leader->p_peers != NULL) {
391 mtx_lock(&ppeers_lock);
392 if (p->p_leader->p_peers != NULL) {
393 q = p->p_leader;
394 while (q->p_peers != p)
395 q = q->p_peers;
396 q->p_peers = p->p_peers;
397 wakeup(p->p_leader);
398 }
399 mtx_unlock(&ppeers_lock);
400 }
401
402 vmspace_exit(td);
403 killjobc();
404 (void)acct_process(td);
405
406 #ifdef KTRACE
407 ktrprocexit(td);
408 #endif
409 /*
410 * Release reference to text vnode
411 */
412 if (p->p_textvp != NULL) {
413 vrele(p->p_textvp);
414 p->p_textvp = NULL;
415 }
416
417 /*
418 * Release our limits structure.
419 */
420 lim_free(p->p_limit);
421 p->p_limit = NULL;
422
423 tidhash_remove(td);
424
425 /*
426 * Call machine-dependent code to release any
427 * machine-dependent resources other than the address space.
428 * The address space is released by "vmspace_exitfree(p)" in
429 * vm_waitproc().
430 */
431 cpu_exit(td);
432
433 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
434
435 sx_xlock(&proctree_lock);
436 /*
437 * Remove proc from allproc queue and pidhash chain.
438 * Place onto zombproc. Unlink from parent's child list.
439 */
440 sx_xlock(&allproc_lock);
441 LIST_REMOVE(p, p_list);
442 LIST_INSERT_HEAD(&zombproc, p, p_list);
443 LIST_REMOVE(p, p_hash);
444 sx_xunlock(&allproc_lock);
445
446 /*
447 * Reparent all children processes:
448 * - traced ones to the original parent (or init if we are that parent)
449 * - the rest to init
450 */
451 q = LIST_FIRST(&p->p_children);
452 if (q != NULL) /* only need this if any child is S_ZOMB */
453 wakeup(q->p_reaper);
454 for (; q != NULL; q = nq) {
455 nq = LIST_NEXT(q, p_sibling);
456 ksi = ksiginfo_alloc(TRUE);
457 PROC_LOCK(q);
458 q->p_sigparent = SIGCHLD;
459
460 if (!(q->p_flag & P_TRACED)) {
461 proc_reparent(q, q->p_reaper);
462 if (q->p_state == PRS_ZOMBIE) {
463 /*
464 * Inform reaper about the reparented
465 * zombie, since wait(2) has something
466 * new to report. Guarantee queueing
467 * of the SIGCHLD signal, similar to
468 * the _exit() behaviour, by providing
469 * our ksiginfo. Ksi is freed by the
470 * signal delivery.
471 */
472 if (q->p_ksi == NULL) {
473 ksi1 = NULL;
474 } else {
475 ksiginfo_copy(q->p_ksi, ksi);
476 ksi->ksi_flags |= KSI_INS;
477 ksi1 = ksi;
478 ksi = NULL;
479 }
480 PROC_LOCK(q->p_reaper);
481 pksignal(q->p_reaper, SIGCHLD, ksi1);
482 PROC_UNLOCK(q->p_reaper);
483 } else if (q->p_pdeathsig > 0) {
484 /*
485 * The child asked to received a signal
486 * when we exit.
487 */
488 kern_psignal(q, q->p_pdeathsig);
489 }
490 } else {
491 /*
492 * Traced processes are killed since their existence
493 * means someone is screwing up.
494 */
495 t = proc_realparent(q);
496 if (t == p) {
497 proc_reparent(q, q->p_reaper);
498 } else {
499 PROC_LOCK(t);
500 proc_reparent(q, t);
501 PROC_UNLOCK(t);
502 }
503 /*
504 * Since q was found on our children list, the
505 * proc_reparent() call moved q to the orphan
506 * list due to present P_TRACED flag. Clear
507 * orphan link for q now while q is locked.
508 */
509 clear_orphan(q);
510 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
511 q->p_flag2 &= ~P2_PTRACE_FSTP;
512 q->p_ptevents = 0;
513 FOREACH_THREAD_IN_PROC(q, tdt) {
514 tdt->td_dbgflags &= ~(TDB_SUSPEND | TDB_XSIG |
515 TDB_FSTP);
516 }
517 kern_psignal(q, SIGKILL);
518 }
519 PROC_UNLOCK(q);
520 if (ksi != NULL)
521 ksiginfo_free(ksi);
522 }
523
524 /*
525 * Also get rid of our orphans.
526 */
527 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) {
528 PROC_LOCK(q);
529 /*
530 * If we are the real parent of this process
531 * but it has been reparented to a debugger, then
532 * check if it asked for a signal when we exit.
533 */
534 if (q->p_pdeathsig > 0)
535 kern_psignal(q, q->p_pdeathsig);
536 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid,
537 q->p_pid);
538 clear_orphan(q);
539 PROC_UNLOCK(q);
540 }
541
542 /* Save exit status. */
543 PROC_LOCK(p);
544 p->p_xthread = td;
545
546 #ifdef KDTRACE_HOOKS
547 /*
548 * Tell the DTrace fasttrap provider about the exit if it
549 * has declared an interest.
550 */
551 if (dtrace_fasttrap_exit)
552 dtrace_fasttrap_exit(p);
553 #endif
554
555 /*
556 * Notify interested parties of our demise.
557 */
558 KNOTE_LOCKED(p->p_klist, NOTE_EXIT);
559
560 #ifdef KDTRACE_HOOKS
561 int reason = CLD_EXITED;
562 if (WCOREDUMP(signo))
563 reason = CLD_DUMPED;
564 else if (WIFSIGNALED(signo))
565 reason = CLD_KILLED;
566 SDT_PROBE1(proc, , , exit, reason);
567 #endif
568
569 /*
570 * If this is a process with a descriptor, we may not need to deliver
571 * a signal to the parent. proctree_lock is held over
572 * procdesc_exit() to serialize concurrent calls to close() and
573 * exit().
574 */
575 signal_parent = 0;
576 if (p->p_procdesc == NULL || procdesc_exit(p)) {
577 /*
578 * Notify parent that we're gone. If parent has the
579 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN,
580 * notify process 1 instead (and hope it will handle this
581 * situation).
582 */
583 PROC_LOCK(p->p_pptr);
584 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
585 if (p->p_pptr->p_sigacts->ps_flag &
586 (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
587 struct proc *pp;
588
589 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
590 pp = p->p_pptr;
591 PROC_UNLOCK(pp);
592 proc_reparent(p, p->p_reaper);
593 p->p_sigparent = SIGCHLD;
594 PROC_LOCK(p->p_pptr);
595
596 /*
597 * Notify parent, so in case he was wait(2)ing or
598 * executing waitpid(2) with our pid, he will
599 * continue.
600 */
601 wakeup(pp);
602 } else
603 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
604
605 if (p->p_pptr == p->p_reaper || p->p_pptr == initproc) {
606 signal_parent = 1;
607 } else if (p->p_sigparent != 0) {
608 if (p->p_sigparent == SIGCHLD) {
609 signal_parent = 1;
610 } else { /* LINUX thread */
611 signal_parent = 2;
612 }
613 }
614 } else
615 PROC_LOCK(p->p_pptr);
616 sx_xunlock(&proctree_lock);
617
618 if (signal_parent == 1) {
619 childproc_exited(p);
620 } else if (signal_parent == 2) {
621 kern_psignal(p->p_pptr, p->p_sigparent);
622 }
623
624 /* Tell the prison that we are gone. */
625 prison_proc_free(p->p_ucred->cr_prison);
626
627 /*
628 * The state PRS_ZOMBIE prevents other proesses from sending
629 * signal to the process, to avoid memory leak, we free memory
630 * for signal queue at the time when the state is set.
631 */
632 sigqueue_flush(&p->p_sigqueue);
633 sigqueue_flush(&td->td_sigqueue);
634
635 /*
636 * We have to wait until after acquiring all locks before
637 * changing p_state. We need to avoid all possible context
638 * switches (including ones from blocking on a mutex) while
639 * marked as a zombie. We also have to set the zombie state
640 * before we release the parent process' proc lock to avoid
641 * a lost wakeup. So, we first call wakeup, then we grab the
642 * sched lock, update the state, and release the parent process'
643 * proc lock.
644 */
645 wakeup(p->p_pptr);
646 cv_broadcast(&p->p_pwait);
647 sched_exit(p->p_pptr, td);
648 PROC_SLOCK(p);
649 p->p_state = PRS_ZOMBIE;
650 PROC_UNLOCK(p->p_pptr);
651
652 /*
653 * Save our children's rusage information in our exit rusage.
654 */
655 PROC_STATLOCK(p);
656 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
657 PROC_STATUNLOCK(p);
658
659 /*
660 * Make sure the scheduler takes this thread out of its tables etc.
661 * This will also release this thread's reference to the ucred.
662 * Other thread parts to release include pcb bits and such.
663 */
664 thread_exit();
665 }
666
667
668 #ifndef _SYS_SYSPROTO_H_
669 struct abort2_args {
670 char *why;
671 int nargs;
672 void **args;
673 };
674 #endif
675
676 int
677 sys_abort2(struct thread *td, struct abort2_args *uap)
678 {
679 struct proc *p = td->td_proc;
680 struct sbuf *sb;
681 void *uargs[16];
682 int error, i, sig;
683
684 /*
685 * Do it right now so we can log either proper call of abort2(), or
686 * note, that invalid argument was passed. 512 is big enough to
687 * handle 16 arguments' descriptions with additional comments.
688 */
689 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
690 sbuf_clear(sb);
691 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
692 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
693 /*
694 * Since we can't return from abort2(), send SIGKILL in cases, where
695 * abort2() was called improperly
696 */
697 sig = SIGKILL;
698 /* Prevent from DoSes from user-space. */
699 if (uap->nargs < 0 || uap->nargs > 16)
700 goto out;
701 if (uap->nargs > 0) {
702 if (uap->args == NULL)
703 goto out;
704 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
705 if (error != 0)
706 goto out;
707 }
708 /*
709 * Limit size of 'reason' string to 128. Will fit even when
710 * maximal number of arguments was chosen to be logged.
711 */
712 if (uap->why != NULL) {
713 error = sbuf_copyin(sb, uap->why, 128);
714 if (error < 0)
715 goto out;
716 } else {
717 sbuf_printf(sb, "(null)");
718 }
719 if (uap->nargs > 0) {
720 sbuf_printf(sb, "(");
721 for (i = 0;i < uap->nargs; i++)
722 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
723 sbuf_printf(sb, ")");
724 }
725 /*
726 * Final stage: arguments were proper, string has been
727 * successfully copied from userspace, and copying pointers
728 * from user-space succeed.
729 */
730 sig = SIGABRT;
731 out:
732 if (sig == SIGKILL) {
733 sbuf_trim(sb);
734 sbuf_printf(sb, " (Reason text inaccessible)");
735 }
736 sbuf_cat(sb, "\n");
737 sbuf_finish(sb);
738 log(LOG_INFO, "%s", sbuf_data(sb));
739 sbuf_delete(sb);
740 exit1(td, 0, sig);
741 return (0);
742 }
743
744
745 #ifdef COMPAT_43
746 /*
747 * The dirty work is handled by kern_wait().
748 */
749 int
750 owait(struct thread *td, struct owait_args *uap __unused)
751 {
752 int error, status;
753
754 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
755 if (error == 0)
756 td->td_retval[1] = status;
757 return (error);
758 }
759 #endif /* COMPAT_43 */
760
761 /*
762 * The dirty work is handled by kern_wait().
763 */
764 int
765 sys_wait4(struct thread *td, struct wait4_args *uap)
766 {
767 struct rusage ru, *rup;
768 int error, status;
769
770 if (uap->rusage != NULL)
771 rup = &ru;
772 else
773 rup = NULL;
774 error = kern_wait(td, uap->pid, &status, uap->options, rup);
775 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0)
776 error = copyout(&status, uap->status, sizeof(status));
777 if (uap->rusage != NULL && error == 0 && td->td_retval[0] != 0)
778 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
779 return (error);
780 }
781
782 int
783 sys_wait6(struct thread *td, struct wait6_args *uap)
784 {
785 struct __wrusage wru, *wrup;
786 siginfo_t si, *sip;
787 idtype_t idtype;
788 id_t id;
789 int error, status;
790
791 idtype = uap->idtype;
792 id = uap->id;
793
794 if (uap->wrusage != NULL)
795 wrup = &wru;
796 else
797 wrup = NULL;
798
799 if (uap->info != NULL) {
800 sip = &si;
801 bzero(sip, sizeof(*sip));
802 } else
803 sip = NULL;
804
805 /*
806 * We expect all callers of wait6() to know about WEXITED and
807 * WTRAPPED.
808 */
809 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip);
810
811 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0)
812 error = copyout(&status, uap->status, sizeof(status));
813 if (uap->wrusage != NULL && error == 0 && td->td_retval[0] != 0)
814 error = copyout(&wru, uap->wrusage, sizeof(wru));
815 if (uap->info != NULL && error == 0)
816 error = copyout(&si, uap->info, sizeof(si));
817 return (error);
818 }
819
820 /*
821 * Reap the remains of a zombie process and optionally return status and
822 * rusage. Asserts and will release both the proctree_lock and the process
823 * lock as part of its work.
824 */
825 void
826 proc_reap(struct thread *td, struct proc *p, int *status, int options)
827 {
828 struct proc *q, *t;
829
830 sx_assert(&proctree_lock, SA_XLOCKED);
831 PROC_LOCK_ASSERT(p, MA_OWNED);
832 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
833
834 mtx_spin_wait_unlocked(&p->p_slock);
835
836 q = td->td_proc;
837
838 if (status)
839 *status = KW_EXITCODE(p->p_xexit, p->p_xsig);
840 if (options & WNOWAIT) {
841 /*
842 * Only poll, returning the status. Caller does not wish to
843 * release the proc struct just yet.
844 */
845 PROC_UNLOCK(p);
846 sx_xunlock(&proctree_lock);
847 return;
848 }
849
850 PROC_LOCK(q);
851 sigqueue_take(p->p_ksi);
852 PROC_UNLOCK(q);
853
854 /*
855 * If we got the child via a ptrace 'attach', we need to give it back
856 * to the old parent.
857 */
858 if (p->p_oppid != 0 && p->p_oppid != p->p_pptr->p_pid) {
859 PROC_UNLOCK(p);
860 t = proc_realparent(p);
861 PROC_LOCK(t);
862 PROC_LOCK(p);
863 CTR2(KTR_PTRACE,
864 "wait: traced child %d moved back to parent %d", p->p_pid,
865 t->p_pid);
866 proc_reparent(p, t);
867 p->p_oppid = 0;
868 PROC_UNLOCK(p);
869 pksignal(t, SIGCHLD, p->p_ksi);
870 wakeup(t);
871 cv_broadcast(&p->p_pwait);
872 PROC_UNLOCK(t);
873 sx_xunlock(&proctree_lock);
874 return;
875 }
876 p->p_oppid = 0;
877 PROC_UNLOCK(p);
878
879 /*
880 * Remove other references to this process to ensure we have an
881 * exclusive reference.
882 */
883 sx_xlock(&allproc_lock);
884 LIST_REMOVE(p, p_list); /* off zombproc */
885 sx_xunlock(&allproc_lock);
886 LIST_REMOVE(p, p_sibling);
887 reaper_abandon_children(p, true);
888 LIST_REMOVE(p, p_reapsibling);
889 PROC_LOCK(p);
890 clear_orphan(p);
891 PROC_UNLOCK(p);
892 leavepgrp(p);
893 if (p->p_procdesc != NULL)
894 procdesc_reap(p);
895 sx_xunlock(&proctree_lock);
896
897 PROC_LOCK(p);
898 knlist_detach(p->p_klist);
899 p->p_klist = NULL;
900 PROC_UNLOCK(p);
901
902 /*
903 * Removal from allproc list and process group list paired with
904 * PROC_LOCK which was executed during that time should guarantee
905 * nothing can reach this process anymore. As such further locking
906 * is unnecessary.
907 */
908 p->p_xexit = p->p_xsig = 0; /* XXX: why? */
909
910 PROC_LOCK(q);
911 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
912 PROC_UNLOCK(q);
913
914 /*
915 * Decrement the count of procs running with this uid.
916 */
917 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
918
919 /*
920 * Destroy resource accounting information associated with the process.
921 */
922 #ifdef RACCT
923 if (racct_enable) {
924 PROC_LOCK(p);
925 racct_sub(p, RACCT_NPROC, 1);
926 PROC_UNLOCK(p);
927 }
928 #endif
929 racct_proc_exit(p);
930
931 /*
932 * Free credentials, arguments, and sigacts.
933 */
934 crfree(p->p_ucred);
935 proc_set_cred(p, NULL);
936 pargs_drop(p->p_args);
937 p->p_args = NULL;
938 sigacts_free(p->p_sigacts);
939 p->p_sigacts = NULL;
940
941 /*
942 * Do any thread-system specific cleanups.
943 */
944 thread_wait(p);
945
946 /*
947 * Give vm and machine-dependent layer a chance to free anything that
948 * cpu_exit couldn't release while still running in process context.
949 */
950 vm_waitproc(p);
951 #ifdef MAC
952 mac_proc_destroy(p);
953 #endif
954
955 KASSERT(FIRST_THREAD_IN_PROC(p),
956 ("proc_reap: no residual thread!"));
957 uma_zfree(proc_zone, p);
958 atomic_add_int(&nprocs, -1);
959 }
960
961 static int
962 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
963 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo,
964 int check_only)
965 {
966 struct rusage *rup;
967
968 sx_assert(&proctree_lock, SA_XLOCKED);
969
970 PROC_LOCK(p);
971
972 switch (idtype) {
973 case P_ALL:
974 if (p->p_procdesc != NULL) {
975 PROC_UNLOCK(p);
976 return (0);
977 }
978 break;
979 case P_PID:
980 if (p->p_pid != (pid_t)id) {
981 PROC_UNLOCK(p);
982 return (0);
983 }
984 break;
985 case P_PGID:
986 if (p->p_pgid != (pid_t)id) {
987 PROC_UNLOCK(p);
988 return (0);
989 }
990 break;
991 case P_SID:
992 if (p->p_session->s_sid != (pid_t)id) {
993 PROC_UNLOCK(p);
994 return (0);
995 }
996 break;
997 case P_UID:
998 if (p->p_ucred->cr_uid != (uid_t)id) {
999 PROC_UNLOCK(p);
1000 return (0);
1001 }
1002 break;
1003 case P_GID:
1004 if (p->p_ucred->cr_gid != (gid_t)id) {
1005 PROC_UNLOCK(p);
1006 return (0);
1007 }
1008 break;
1009 case P_JAILID:
1010 if (p->p_ucred->cr_prison->pr_id != (int)id) {
1011 PROC_UNLOCK(p);
1012 return (0);
1013 }
1014 break;
1015 /*
1016 * It seems that the thread structures get zeroed out
1017 * at process exit. This makes it impossible to
1018 * support P_SETID, P_CID or P_CPUID.
1019 */
1020 default:
1021 PROC_UNLOCK(p);
1022 return (0);
1023 }
1024
1025 if (p_canwait(td, p)) {
1026 PROC_UNLOCK(p);
1027 return (0);
1028 }
1029
1030 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) {
1031 PROC_UNLOCK(p);
1032 return (0);
1033 }
1034
1035 /*
1036 * This special case handles a kthread spawned by linux_clone
1037 * (see linux_misc.c). The linux_wait4 and linux_waitpid
1038 * functions need to be able to distinguish between waiting
1039 * on a process and waiting on a thread. It is a thread if
1040 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
1041 * signifies we want to wait for threads and not processes.
1042 */
1043 if ((p->p_sigparent != SIGCHLD) ^
1044 ((options & WLINUXCLONE) != 0)) {
1045 PROC_UNLOCK(p);
1046 return (0);
1047 }
1048
1049 if (siginfo != NULL) {
1050 bzero(siginfo, sizeof(*siginfo));
1051 siginfo->si_errno = 0;
1052
1053 /*
1054 * SUSv4 requires that the si_signo value is always
1055 * SIGCHLD. Obey it despite the rfork(2) interface
1056 * allows to request other signal for child exit
1057 * notification.
1058 */
1059 siginfo->si_signo = SIGCHLD;
1060
1061 /*
1062 * This is still a rough estimate. We will fix the
1063 * cases TRAPPED, STOPPED, and CONTINUED later.
1064 */
1065 if (WCOREDUMP(p->p_xsig)) {
1066 siginfo->si_code = CLD_DUMPED;
1067 siginfo->si_status = WTERMSIG(p->p_xsig);
1068 } else if (WIFSIGNALED(p->p_xsig)) {
1069 siginfo->si_code = CLD_KILLED;
1070 siginfo->si_status = WTERMSIG(p->p_xsig);
1071 } else {
1072 siginfo->si_code = CLD_EXITED;
1073 siginfo->si_status = p->p_xexit;
1074 }
1075
1076 siginfo->si_pid = p->p_pid;
1077 siginfo->si_uid = p->p_ucred->cr_uid;
1078
1079 /*
1080 * The si_addr field would be useful additional
1081 * detail, but apparently the PC value may be lost
1082 * when we reach this point. bzero() above sets
1083 * siginfo->si_addr to NULL.
1084 */
1085 }
1086
1087 /*
1088 * There should be no reason to limit resources usage info to
1089 * exited processes only. A snapshot about any resources used
1090 * by a stopped process may be exactly what is needed.
1091 */
1092 if (wrusage != NULL) {
1093 rup = &wrusage->wru_self;
1094 *rup = p->p_ru;
1095 PROC_STATLOCK(p);
1096 calcru(p, &rup->ru_utime, &rup->ru_stime);
1097 PROC_STATUNLOCK(p);
1098
1099 rup = &wrusage->wru_children;
1100 *rup = p->p_stats->p_cru;
1101 calccru(p, &rup->ru_utime, &rup->ru_stime);
1102 }
1103
1104 if (p->p_state == PRS_ZOMBIE && !check_only) {
1105 proc_reap(td, p, status, options);
1106 return (-1);
1107 }
1108 return (1);
1109 }
1110
1111 int
1112 kern_wait(struct thread *td, pid_t pid, int *status, int options,
1113 struct rusage *rusage)
1114 {
1115 struct __wrusage wru, *wrup;
1116 idtype_t idtype;
1117 id_t id;
1118 int ret;
1119
1120 /*
1121 * Translate the special pid values into the (idtype, pid)
1122 * pair for kern_wait6. The WAIT_MYPGRP case is handled by
1123 * kern_wait6() on its own.
1124 */
1125 if (pid == WAIT_ANY) {
1126 idtype = P_ALL;
1127 id = 0;
1128 } else if (pid < 0) {
1129 idtype = P_PGID;
1130 id = (id_t)-pid;
1131 } else {
1132 idtype = P_PID;
1133 id = (id_t)pid;
1134 }
1135
1136 if (rusage != NULL)
1137 wrup = &wru;
1138 else
1139 wrup = NULL;
1140
1141 /*
1142 * For backward compatibility we implicitly add flags WEXITED
1143 * and WTRAPPED here.
1144 */
1145 options |= WEXITED | WTRAPPED;
1146 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL);
1147 if (rusage != NULL)
1148 *rusage = wru.wru_self;
1149 return (ret);
1150 }
1151
1152 static void
1153 report_alive_proc(struct thread *td, struct proc *p, siginfo_t *siginfo,
1154 int *status, int options, int si_code)
1155 {
1156 bool cont;
1157
1158 PROC_LOCK_ASSERT(p, MA_OWNED);
1159 sx_assert(&proctree_lock, SA_XLOCKED);
1160 MPASS(si_code == CLD_TRAPPED || si_code == CLD_STOPPED ||
1161 si_code == CLD_CONTINUED);
1162
1163 cont = si_code == CLD_CONTINUED;
1164 if ((options & WNOWAIT) == 0) {
1165 if (cont)
1166 p->p_flag &= ~P_CONTINUED;
1167 else
1168 p->p_flag |= P_WAITED;
1169 PROC_LOCK(td->td_proc);
1170 sigqueue_take(p->p_ksi);
1171 PROC_UNLOCK(td->td_proc);
1172 }
1173 sx_xunlock(&proctree_lock);
1174 if (siginfo != NULL) {
1175 siginfo->si_code = si_code;
1176 siginfo->si_status = cont ? SIGCONT : p->p_xsig;
1177 }
1178 if (status != NULL)
1179 *status = cont ? SIGCONT : W_STOPCODE(p->p_xsig);
1180 PROC_UNLOCK(p);
1181 td->td_retval[0] = p->p_pid;
1182 }
1183
1184 int
1185 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status,
1186 int options, struct __wrusage *wrusage, siginfo_t *siginfo)
1187 {
1188 struct proc *p, *q;
1189 pid_t pid;
1190 int error, nfound, ret;
1191 bool report;
1192
1193 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */
1194 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */
1195 AUDIT_ARG_VALUE(options);
1196
1197 q = td->td_proc;
1198
1199 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) {
1200 PROC_LOCK(q);
1201 id = (id_t)q->p_pgid;
1202 PROC_UNLOCK(q);
1203 idtype = P_PGID;
1204 }
1205
1206 /* If we don't know the option, just return. */
1207 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT |
1208 WEXITED | WTRAPPED | WLINUXCLONE)) != 0)
1209 return (EINVAL);
1210 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) {
1211 /*
1212 * We will be unable to find any matching processes,
1213 * because there are no known events to look for.
1214 * Prefer to return error instead of blocking
1215 * indefinitely.
1216 */
1217 return (EINVAL);
1218 }
1219
1220 loop:
1221 if (q->p_flag & P_STATCHILD) {
1222 PROC_LOCK(q);
1223 q->p_flag &= ~P_STATCHILD;
1224 PROC_UNLOCK(q);
1225 }
1226 sx_xlock(&proctree_lock);
1227 loop_locked:
1228 nfound = 0;
1229 LIST_FOREACH(p, &q->p_children, p_sibling) {
1230 pid = p->p_pid;
1231 ret = proc_to_reap(td, p, idtype, id, status, options,
1232 wrusage, siginfo, 0);
1233 if (ret == 0)
1234 continue;
1235 else if (ret != 1) {
1236 td->td_retval[0] = pid;
1237 return (0);
1238 }
1239
1240 nfound++;
1241 PROC_LOCK_ASSERT(p, MA_OWNED);
1242
1243 if ((options & WTRAPPED) != 0 &&
1244 (p->p_flag & P_TRACED) != 0) {
1245 PROC_SLOCK(p);
1246 report =
1247 ((p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) &&
1248 p->p_suspcount == p->p_numthreads &&
1249 (p->p_flag & P_WAITED) == 0);
1250 PROC_SUNLOCK(p);
1251 if (report) {
1252 CTR4(KTR_PTRACE,
1253 "wait: returning trapped pid %d status %#x "
1254 "(xstat %d) xthread %d",
1255 p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig,
1256 p->p_xthread != NULL ?
1257 p->p_xthread->td_tid : -1);
1258 report_alive_proc(td, p, siginfo, status,
1259 options, CLD_TRAPPED);
1260 return (0);
1261 }
1262 }
1263 if ((options & WUNTRACED) != 0 &&
1264 (p->p_flag & P_STOPPED_SIG) != 0) {
1265 PROC_SLOCK(p);
1266 report = (p->p_suspcount == p->p_numthreads &&
1267 ((p->p_flag & P_WAITED) == 0));
1268 PROC_SUNLOCK(p);
1269 if (report) {
1270 report_alive_proc(td, p, siginfo, status,
1271 options, CLD_STOPPED);
1272 return (0);
1273 }
1274 }
1275 if ((options & WCONTINUED) != 0 &&
1276 (p->p_flag & P_CONTINUED) != 0) {
1277 report_alive_proc(td, p, siginfo, status, options,
1278 CLD_CONTINUED);
1279 return (0);
1280 }
1281 PROC_UNLOCK(p);
1282 }
1283
1284 /*
1285 * Look in the orphans list too, to allow the parent to
1286 * collect it's child exit status even if child is being
1287 * debugged.
1288 *
1289 * Debugger detaches from the parent upon successful
1290 * switch-over from parent to child. At this point due to
1291 * re-parenting the parent loses the child to debugger and a
1292 * wait4(2) call would report that it has no children to wait
1293 * for. By maintaining a list of orphans we allow the parent
1294 * to successfully wait until the child becomes a zombie.
1295 */
1296 if (nfound == 0) {
1297 LIST_FOREACH(p, &q->p_orphans, p_orphan) {
1298 ret = proc_to_reap(td, p, idtype, id, NULL, options,
1299 NULL, NULL, 1);
1300 if (ret != 0) {
1301 KASSERT(ret != -1, ("reaped an orphan (pid %d)",
1302 (int)td->td_retval[0]));
1303 PROC_UNLOCK(p);
1304 nfound++;
1305 break;
1306 }
1307 }
1308 }
1309 if (nfound == 0) {
1310 sx_xunlock(&proctree_lock);
1311 return (ECHILD);
1312 }
1313 if (options & WNOHANG) {
1314 sx_xunlock(&proctree_lock);
1315 td->td_retval[0] = 0;
1316 return (0);
1317 }
1318 PROC_LOCK(q);
1319 if (q->p_flag & P_STATCHILD) {
1320 q->p_flag &= ~P_STATCHILD;
1321 PROC_UNLOCK(q);
1322 goto loop_locked;
1323 }
1324 sx_xunlock(&proctree_lock);
1325 error = msleep(q, &q->p_mtx, PWAIT | PCATCH | PDROP, "wait", 0);
1326 if (error)
1327 return (error);
1328 goto loop;
1329 }
1330
1331 /*
1332 * Make process 'parent' the new parent of process 'child'.
1333 * Must be called with an exclusive hold of proctree lock.
1334 */
1335 void
1336 proc_reparent(struct proc *child, struct proc *parent)
1337 {
1338
1339 sx_assert(&proctree_lock, SX_XLOCKED);
1340 PROC_LOCK_ASSERT(child, MA_OWNED);
1341 if (child->p_pptr == parent)
1342 return;
1343
1344 PROC_LOCK(child->p_pptr);
1345 sigqueue_take(child->p_ksi);
1346 PROC_UNLOCK(child->p_pptr);
1347 LIST_REMOVE(child, p_sibling);
1348 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1349
1350 clear_orphan(child);
1351 if (child->p_flag & P_TRACED) {
1352 if (LIST_EMPTY(&child->p_pptr->p_orphans)) {
1353 child->p_treeflag |= P_TREE_FIRST_ORPHAN;
1354 LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child,
1355 p_orphan);
1356 } else {
1357 LIST_INSERT_AFTER(LIST_FIRST(&child->p_pptr->p_orphans),
1358 child, p_orphan);
1359 }
1360 child->p_treeflag |= P_TREE_ORPHANED;
1361 }
1362
1363 child->p_pptr = parent;
1364 }
Cache object: 6921e2b99e598f1ed1a9c2b46853e96f
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