FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
1 /* $NetBSD: kern_exit.c,v 1.162.2.1 2007/04/01 16:16:20 bouyer Exp $ */
2
3 /*-
4 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 /*
41 * Copyright (c) 1982, 1986, 1989, 1991, 1993
42 * The Regents of the University of California. All rights reserved.
43 * (c) UNIX System Laboratories, Inc.
44 * All or some portions of this file are derived from material licensed
45 * to the University of California by American Telephone and Telegraph
46 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
47 * the permission of UNIX System Laboratories, Inc.
48 *
49 * Redistribution and use in source and binary forms, with or without
50 * modification, are permitted provided that the following conditions
51 * are met:
52 * 1. Redistributions of source code must retain the above copyright
53 * notice, this list of conditions and the following disclaimer.
54 * 2. Redistributions in binary form must reproduce the above copyright
55 * notice, this list of conditions and the following disclaimer in the
56 * documentation and/or other materials provided with the distribution.
57 * 3. Neither the name of the University nor the names of its contributors
58 * may be used to endorse or promote products derived from this software
59 * without specific prior written permission.
60 *
61 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
62 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
63 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
64 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
65 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
66 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
67 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
68 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
69 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
70 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
71 * SUCH DAMAGE.
72 *
73 * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95
74 */
75
76 #include <sys/cdefs.h>
77 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.162.2.1 2007/04/01 16:16:20 bouyer Exp $");
78
79 #include "opt_ktrace.h"
80 #include "opt_perfctrs.h"
81 #include "opt_systrace.h"
82 #include "opt_sysv.h"
83
84 #include <sys/param.h>
85 #include <sys/systm.h>
86 #include <sys/ioctl.h>
87 #include <sys/tty.h>
88 #include <sys/time.h>
89 #include <sys/resource.h>
90 #include <sys/kernel.h>
91 #include <sys/ktrace.h>
92 #include <sys/proc.h>
93 #include <sys/buf.h>
94 #include <sys/wait.h>
95 #include <sys/file.h>
96 #include <sys/vnode.h>
97 #include <sys/syslog.h>
98 #include <sys/malloc.h>
99 #include <sys/pool.h>
100 #include <sys/resourcevar.h>
101 #if defined(PERFCTRS)
102 #include <sys/pmc.h>
103 #endif
104 #include <sys/ptrace.h>
105 #include <sys/acct.h>
106 #include <sys/filedesc.h>
107 #include <sys/ras.h>
108 #include <sys/signalvar.h>
109 #include <sys/sched.h>
110 #include <sys/sa.h>
111 #include <sys/savar.h>
112 #include <sys/mount.h>
113 #include <sys/syscallargs.h>
114 #include <sys/systrace.h>
115 #include <sys/kauth.h>
116
117 #include <machine/cpu.h>
118
119 #include <uvm/uvm_extern.h>
120
121 #define DEBUG_EXIT
122
123 #ifdef DEBUG_EXIT
124 int debug_exit = 0;
125 #define DPRINTF(x) if (debug_exit) printf x
126 #else
127 #define DPRINTF(x)
128 #endif
129
130 static void lwp_exit_hook(struct lwp *, void *);
131
132 /*
133 * Fill in the appropriate signal information, and signal the parent.
134 */
135 static void
136 exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi)
137 {
138
139 (void)memset(ksi, 0, sizeof(ksiginfo_t));
140 if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) {
141 if (WIFSIGNALED(p->p_xstat)) {
142 if (WCOREDUMP(p->p_xstat))
143 ksi->ksi_code = CLD_DUMPED;
144 else
145 ksi->ksi_code = CLD_KILLED;
146 } else {
147 ksi->ksi_code = CLD_EXITED;
148 }
149 }
150 /*
151 * we fill those in, even for non-SIGCHLD.
152 */
153 ksi->ksi_pid = p->p_pid;
154 ksi->ksi_uid = kauth_cred_geteuid(p->p_cred);
155 ksi->ksi_status = p->p_xstat;
156 /* XXX: is this still valid? */
157 ksi->ksi_utime = p->p_ru->ru_utime.tv_sec;
158 ksi->ksi_stime = p->p_ru->ru_stime.tv_sec;
159 }
160
161 /*
162 * exit --
163 * Death of process.
164 */
165 int
166 sys_exit(struct lwp *l, void *v, register_t *retval)
167 {
168 struct sys_exit_args /* {
169 syscallarg(int) rval;
170 } */ *uap = v;
171
172 /* Don't call exit1() multiple times in the same process.*/
173 if (l->l_proc->p_flag & P_WEXIT)
174 lwp_exit(l);
175
176 exit1(l, W_EXITCODE(SCARG(uap, rval), 0));
177 /* NOTREACHED */
178 return (0);
179 }
180
181 /*
182 * Exit: deallocate address space and other resources, change proc state
183 * to zombie, and unlink proc from allproc and parent's lists. Save exit
184 * status and rusage for wait(). Check for child processes and orphan them.
185 */
186 void
187 exit1(struct lwp *l, int rv)
188 {
189 struct proc *p, *q, *nq;
190 int s, sa;
191 ksiginfo_t ksi;
192 int do_psignal = 0;
193
194 p = l->l_proc;
195
196 if (__predict_false(p == initproc))
197 panic("init died (signal %d, exit %d)",
198 WTERMSIG(rv), WEXITSTATUS(rv));
199
200 p->p_flag |= P_WEXIT;
201 if (p->p_flag & P_STOPEXIT) {
202 sigminusset(&contsigmask, &p->p_sigctx.ps_siglist);
203 SCHED_LOCK(s);
204 p->p_stat = SSTOP;
205 l->l_stat = LSSTOP;
206 p->p_nrlwps--;
207 mi_switch(l, NULL);
208 SCHED_ASSERT_UNLOCKED();
209 splx(s);
210 }
211
212 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid));
213 /*
214 * Disable scheduler activation upcalls.
215 * We're trying to get out of here.
216 */
217 sa = 0;
218 if (p->p_sa != NULL) {
219 l->l_flag &= ~L_SA;
220 #if 0
221 p->p_flag &= ~P_SA;
222 #endif
223 sa = 1;
224 }
225
226 #ifdef PGINPROF
227 vmsizmon();
228 #endif
229 if (p->p_flag & P_PROFIL)
230 stopprofclock(p);
231 p->p_ru = pool_get(&rusage_pool, PR_WAITOK);
232 /*
233 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we
234 * wake up the parent early to avoid deadlock.
235 */
236 if (p->p_flag & P_PPWAIT) {
237 p->p_flag &= ~P_PPWAIT;
238 wakeup(p->p_pptr);
239 }
240 sigfillset(&p->p_sigctx.ps_sigignore);
241 sigemptyset(&p->p_sigctx.ps_siglist);
242 p->p_sigctx.ps_sigcheck = 0;
243 p->p_stat = SDYING;
244 timers_free(p, TIMERS_ALL);
245
246 if (sa || (p->p_nlwps > 1)) {
247 exit_lwps(l);
248
249 /*
250 * Collect thread u-areas.
251 */
252 uvm_uarea_drain(FALSE);
253 }
254
255 #if defined(__HAVE_RAS)
256 ras_purgeall(p);
257 #endif
258
259 /*
260 * Close open files and release open-file table.
261 * This may block!
262 */
263 fdfree(l);
264 cwdfree(p->p_cwdi);
265 p->p_cwdi = 0;
266
267 doexithooks(p);
268
269 if (SESS_LEADER(p)) {
270 struct session *sp = p->p_session;
271 struct tty *tp;
272
273 if (sp->s_ttyvp) {
274 /*
275 * Controlling process.
276 * Signal foreground pgrp,
277 * drain controlling terminal
278 * and revoke access to controlling terminal.
279 */
280 tp = sp->s_ttyp;
281 s = spltty();
282 TTY_LOCK(tp);
283 if (tp->t_session == sp) {
284 if (tp->t_pgrp)
285 pgsignal(tp->t_pgrp, SIGHUP, 1);
286 /* we can't guarantee the revoke will do this */
287 tp->t_pgrp = NULL;
288 tp->t_session = NULL;
289 TTY_UNLOCK(tp);
290 splx(s);
291 SESSRELE(sp);
292 (void) ttywait(tp);
293 /*
294 * The tty could have been revoked
295 * if we blocked.
296 */
297 if (sp->s_ttyvp)
298 VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
299 } else {
300 TTY_UNLOCK(tp);
301 splx(s);
302 }
303 if (sp->s_ttyvp)
304 vrele(sp->s_ttyvp);
305 sp->s_ttyvp = NULL;
306 /*
307 * s_ttyp is not zero'd; we use this to indicate
308 * that the session once had a controlling terminal.
309 * (for logging and informational purposes)
310 */
311 }
312 sp->s_leader = NULL;
313 }
314 fixjobc(p, p->p_pgrp, 0);
315
316 /*
317 * Collect accounting flags from the last remaining LWP (this one),
318 * and write out accounting data.
319 */
320 p->p_acflag |= l->l_acflag;
321 (void)acct_process(l);
322
323 #ifdef KTRACE
324 /*
325 * Release trace file.
326 */
327 ktrderef(p);
328 #endif
329 #ifdef SYSTRACE
330 systrace_sys_exit(p);
331 #endif
332
333 /*
334 * If emulation has process exit hook, call it now.
335 * Set the exit status now so that the exit hook has
336 * an opportunity to tweak it (COMPAT_LINUX requires
337 * this for thread group emulation)
338 */
339 p->p_xstat = rv;
340 if (p->p_emul->e_proc_exit)
341 (*p->p_emul->e_proc_exit)(p);
342
343 /*
344 * Free the VM resources we're still holding on to.
345 * We must do this from a valid thread because doing
346 * so may block. This frees vmspace, which we don't
347 * need anymore. The only remaining lwp is the one
348 * we run at this moment, nothing runs in userland
349 * anymore.
350 */
351 uvm_proc_exit(p);
352
353 /* Release substructures. These might need to sleep. */
354 kauth_cred_free(l->l_cred);
355 sigactsfree(p->p_sigacts);
356 p->p_sigacts = NULL;
357
358 /*
359 * Finalize the last LWP's specificdata, as well as the
360 * specificdata for the proc itself.
361 */
362 lwp_finispecific(l);
363 proc_finispecific(p);
364
365 /*
366 * Give machine-dependent code a chance to free any
367 * MD LWP resources while we can still block. This must be done
368 * before uvm_lwp_exit(), in case these resources are in the
369 * PCB.
370 * THIS IS LAST BLOCKING OPERATION.
371 */
372 #ifndef __NO_CPU_LWP_FREE
373 cpu_lwp_free(l, 1);
374 #endif
375
376 pmap_deactivate(l);
377
378 /*
379 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP!
380 */
381
382 /*
383 * Save final rusage info, adding in child rusage info and self times.
384 * In order to pick up the time for the current execution, we must
385 * do this before unlinking the lwp from l_list.
386 */
387 *p->p_ru = p->p_stats->p_ru;
388 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
389 ruadd(p->p_ru, &p->p_stats->p_cru);
390
391 /*
392 * Notify interested parties of our demise.
393 */
394 KNOTE(&p->p_klist, NOTE_EXIT);
395
396 #if PERFCTRS
397 /*
398 * Save final PMC information in parent process & clean up.
399 */
400 if (PMC_ENABLED(p)) {
401 pmc_save_context(p);
402 pmc_accumulate(p->p_pptr, p);
403 pmc_process_exit(p);
404 }
405 #endif
406
407 s = proclist_lock_write();
408 /*
409 * Reset p_opptr pointer of all former children which got
410 * traced by another process and were reparented. We reset
411 * it to NULL here; the trace detach code then reparents
412 * the child to initproc. We only check allproc list, since
413 * eventual former children on zombproc list won't reference
414 * p_opptr anymore.
415 */
416 if (p->p_flag & P_CHTRACED) {
417 PROCLIST_FOREACH(q, &allproc) {
418 if (q->p_opptr == p)
419 q->p_opptr = NULL;
420 }
421 }
422
423 /*
424 * Give orphaned children to init(8).
425 */
426 q = LIST_FIRST(&p->p_children);
427 if (q) /* only need this if any child is SZOMB */
428 wakeup(initproc);
429 for (; q != NULL; q = nq) {
430 nq = LIST_NEXT(q, p_sibling);
431
432 /*
433 * Traced processes are killed since their existence
434 * means someone is screwing up. Since we reset the
435 * trace flags, the logic in sys_wait4() would not be
436 * triggered to reparent the process to its
437 * original parent, so we must do this here.
438 */
439 if (q->p_flag & P_TRACED) {
440 if (q->p_opptr != q->p_pptr) {
441 struct proc *t = q->p_opptr;
442 proc_reparent(q, t ? t : initproc);
443 q->p_opptr = NULL;
444 } else
445 proc_reparent(q, initproc);
446 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL);
447 killproc(q, "orphaned traced process");
448 } else {
449 proc_reparent(q, initproc);
450 }
451 }
452
453 /*
454 * Move proc from allproc to zombproc, it's now ready
455 * to be collected by parent. Remaining lwp resources
456 * will be freed in lwp_exit2() once we've switch to idle
457 * context.
458 * Changing the state to SZOMB stops it being found by pfind().
459 */
460 LIST_REMOVE(p, p_list);
461 LIST_INSERT_HEAD(&zombproc, p, p_list);
462 p->p_stat = SZOMB;
463
464 LIST_REMOVE(l, l_list);
465 LIST_REMOVE(l, l_sibling);
466 l->l_flag |= L_DETACHED; /* detached from proc too */
467 l->l_stat = LSDEAD;
468
469 KASSERT(p->p_nrlwps == 1);
470 KASSERT(p->p_nlwps == 1);
471 p->p_nrlwps--;
472 p->p_nlwps--;
473
474 /* Put in front of parent's sibling list for parent to collect it */
475 q = p->p_pptr;
476 q->p_nstopchild++;
477 if (LIST_FIRST(&q->p_children) != p) {
478 /* Put child where it can be found quickly */
479 LIST_REMOVE(p, p_sibling);
480 LIST_INSERT_HEAD(&q->p_children, p, p_sibling);
481 }
482
483 /*
484 * Notify parent that we're gone. If parent has the P_NOCLDWAIT
485 * flag set, notify init instead (and hope it will handle
486 * this situation).
487 */
488 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) {
489 proc_reparent(p, initproc);
490
491 /*
492 * If this was the last child of our parent, notify
493 * parent, so in case he was wait(2)ing, he will
494 * continue.
495 */
496 if (LIST_FIRST(&q->p_children) == NULL)
497 wakeup(q);
498 }
499
500 /*
501 * Clear curlwp after we've done all operations
502 * that could block, and before tearing down the rest
503 * of the process state that might be used from clock, etc.
504 * Also, can't clear curlwp while we're still runnable,
505 * as we're not on a run queue (we are current, just not
506 * a proper proc any longer!).
507 *
508 * Other substructures are freed from wait().
509 */
510 curlwp = NULL;
511
512 /* Reload parent pointer, since p may have been reparented above */
513 q = p->p_pptr;
514
515 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) {
516 exit_psignal(p, q, &ksi);
517 do_psignal = 1;
518 }
519
520 /*
521 * Once we release the proclist lock, we shouldn't touch the
522 * process structure anymore, since it's now on the zombie
523 * list and available for collection by the parent.
524 */
525 proclist_unlock_write(s);
526
527 if (do_psignal)
528 kpsignal(q, &ksi, NULL);
529
530 /* Wake up the parent so it can get exit status. */
531 wakeup(q);
532
533 #ifdef DEBUG
534 /* Nothing should use the process link anymore */
535 l->l_proc = NULL;
536 #endif
537
538 /* This process no longer needs to hold the kernel lock. */
539 KERNEL_PROC_UNLOCK(l);
540
541 /*
542 * Finally, call machine-dependent code to switch to a new
543 * context (possibly the idle context). Once we are no longer
544 * using the dead lwp's stack, lwp_exit2() will be called
545 * to arrange for the resources to be released.
546 *
547 * Note that cpu_exit() will end with a call equivalent to
548 * cpu_switch(), finishing our execution (pun intended).
549 */
550
551 uvmexp.swtch++;
552 cpu_exit(l);
553 }
554
555 void
556 exit_lwps(struct lwp *l)
557 {
558 struct proc *p;
559 struct lwp *l2;
560 struct sadata_vp *vp;
561 int s, error;
562 lwpid_t waited;
563
564 p = l->l_proc;
565
566 /* XXX SMP
567 * This would be the right place to IPI any LWPs running on
568 * other processors so that they can notice the userret exit hook.
569 */
570 p->p_userret = lwp_exit_hook;
571 p->p_userret_arg = NULL;
572
573 if (p->p_sa) {
574 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) {
575 /*
576 * Make SA-cached LWPs normal process runnable
577 * LWPs so that they'll also self-destruct.
578 */
579 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ",
580 p->p_pid, vp->savp_id));
581 SCHED_LOCK(s);
582 while ((l2 = sa_getcachelwp(vp)) != 0) {
583 l2->l_priority = l2->l_usrpri;
584 setrunnable(l2);
585 DPRINTF(("%d ", l2->l_lid));
586 }
587 SCHED_UNLOCK(s);
588 DPRINTF(("\n"));
589
590 /*
591 * Clear wokenq, the LWPs on the queue will
592 * run below.
593 */
594 vp->savp_wokenq_head = NULL;
595 }
596 }
597
598 retry:
599 /*
600 * Interrupt LWPs in interruptable sleep, unsuspend suspended
601 * LWPs, make detached LWPs undetached (so we can wait for
602 * them) and then wait for everyone else to finish.
603 */
604 LIST_FOREACH(l2, &p->p_lwps, l_sibling) {
605 l2->l_flag &= ~(L_DETACHED|L_SA);
606
607 SCHED_LOCK(s);
608 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) ||
609 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) {
610 setrunnable(l2);
611 DPRINTF(("exit_lwps: Made %d.%d runnable\n",
612 p->p_pid, l2->l_lid));
613 }
614 SCHED_UNLOCK(s);
615 }
616
617
618 while (p->p_nlwps > 1) {
619 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n",
620 p->p_nlwps, p->p_nrlwps, p->p_nzlwps));
621 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL);
622 if (error == EDEADLK) {
623 /*
624 * LWPs can get suspended/slept behind us.
625 * (eg. sa_setwoken)
626 * kick them again and retry.
627 */
628 goto retry;
629 }
630 if (error)
631 panic("exit_lwps: lwp_wait1 failed with error %d",
632 error);
633 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited));
634 }
635
636 p->p_userret = NULL;
637 }
638
639 /* Wrapper function for use in p_userret */
640 static void
641 lwp_exit_hook(struct lwp *l, void *arg)
642 {
643
644 KERNEL_PROC_LOCK(l);
645 lwp_exit(l);
646 }
647
648 int
649 sys_wait4(struct lwp *l, void *v, register_t *retval)
650 {
651 struct sys_wait4_args /* {
652 syscallarg(int) pid;
653 syscallarg(int *) status;
654 syscallarg(int) options;
655 syscallarg(struct rusage *) rusage;
656 } */ *uap = v;
657 struct proc *child, *parent;
658 int status, error;
659
660 parent = l->l_proc;
661
662 if (SCARG(uap, pid) == 0)
663 SCARG(uap, pid) = -parent->p_pgid;
664 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG))
665 return (EINVAL);
666
667 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options),
668 &child);
669 if (error != 0)
670 return error;
671 if (child == NULL) {
672 *retval = 0;
673 return 0;
674 }
675
676 /*
677 * Collect child u-areas.
678 */
679 uvm_uarea_drain(FALSE);
680
681 retval[0] = child->p_pid;
682
683 if (P_ZOMBIE(child)) {
684 if (SCARG(uap, status)) {
685 status = child->p_xstat; /* convert to int */
686 error = copyout(&status, SCARG(uap, status),
687 sizeof(status));
688 if (error)
689 return (error);
690 }
691 if (SCARG(uap, rusage)) {
692 error = copyout(child->p_ru, SCARG(uap, rusage),
693 sizeof(struct rusage));
694 if (error)
695 return (error);
696 }
697
698 proc_free(child);
699 return 0;
700 }
701
702 /* child state must be SSTOP */
703 if (SCARG(uap, status)) {
704 status = W_STOPCODE(child->p_xstat);
705 return copyout(&status, SCARG(uap, status), sizeof(status));
706 }
707 return 0;
708 }
709
710 /*
711 * Scan list of child processes for a child process that has stopped or
712 * exited. Used by sys_wait4 and 'compat' equivalents.
713 */
714 int
715 find_stopped_child(struct proc *parent, pid_t pid, int options,
716 struct proc **child_p)
717 {
718 struct proc *child;
719 int error;
720
721 for (;;) {
722 proclist_lock_read();
723 error = ECHILD;
724 LIST_FOREACH(child, &parent->p_children, p_sibling) {
725 if (pid >= 0) {
726 if (child->p_pid != pid) {
727 child = p_find(pid, PFIND_ZOMBIE |
728 PFIND_LOCKED);
729 if (child == NULL
730 || child->p_pptr != parent) {
731 child = NULL;
732 break;
733 }
734 }
735 } else
736 if (pid != WAIT_ANY && child->p_pgid != -pid)
737 /* child not in correct pgrp */
738 continue;
739 /*
740 * Wait for processes with p_exitsig != SIGCHLD
741 * processes only if WALTSIG is set; wait for
742 * processes with p_exitsig == SIGCHLD only
743 * if WALTSIG is clear.
744 */
745 if (((options & WALLSIG) == 0) &&
746 (options & WALTSIG ? child->p_exitsig == SIGCHLD
747 : P_EXITSIG(child) != SIGCHLD)){
748 if (child->p_pid == pid) {
749 child = NULL;
750 break;
751 }
752 continue;
753 }
754
755 error = 0;
756 if (child->p_stat == SZOMB && !(options & WNOZOMBIE))
757 break;
758
759 if (child->p_stat == SSTOP &&
760 (child->p_flag & P_WAITED) == 0 &&
761 (child->p_flag & P_TRACED || options & WUNTRACED)) {
762 if ((options & WNOWAIT) == 0) {
763 child->p_flag |= P_WAITED;
764 parent->p_nstopchild--;
765 }
766 break;
767 }
768 if (parent->p_nstopchild == 0 || child->p_pid == pid) {
769 child = NULL;
770 break;
771 }
772 }
773 proclist_unlock_read();
774 if (child != NULL || error != 0 || options & WNOHANG) {
775 *child_p = child;
776 return error;
777 }
778 error = tsleep(parent, PWAIT | PCATCH, "wait", 0);
779 if (error != 0)
780 return error;
781 }
782 }
783
784 /*
785 * Free a process after parent has taken all the state info.
786 */
787 void
788 proc_free(struct proc *p)
789 {
790 struct proc *parent = p->p_pptr;
791 ksiginfo_t ksi;
792 int s;
793
794 KASSERT(p->p_nlwps == 0);
795 KASSERT(p->p_nzlwps == 0);
796 KASSERT(p->p_nrlwps == 0);
797 KASSERT(LIST_EMPTY(&p->p_lwps));
798
799 /*
800 * If we got the child via ptrace(2) or procfs, and
801 * the parent is different (meaning the process was
802 * attached, rather than run as a child), then we need
803 * to give it back to the old parent, and send the
804 * parent the exit signal. The rest of the cleanup
805 * will be done when the old parent waits on the child.
806 */
807 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){
808 parent = p->p_opptr;
809 if (parent == NULL)
810 parent = initproc;
811 proc_reparent(p, parent);
812 p->p_opptr = NULL;
813 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL);
814 if (p->p_exitsig != 0) {
815 exit_psignal(p, parent, &ksi);
816 kpsignal(parent, &ksi, NULL);
817 }
818 wakeup(parent);
819 return;
820 }
821
822 scheduler_wait_hook(parent, p);
823 p->p_xstat = 0;
824
825 ruadd(&parent->p_stats->p_cru, p->p_ru);
826
827 /*
828 * At this point we are going to start freeing the final resources.
829 * If anyone tries to access the proc structure after here they
830 * will get a shock - bits are missing.
831 * Attempt to make it hard!
832 */
833
834 p->p_stat = SIDL; /* not even a zombie any more */
835
836 pool_put(&rusage_pool, p->p_ru);
837
838 /*
839 * Finally finished with old proc entry.
840 * Unlink it from its process group and free it.
841 */
842 leavepgrp(p);
843
844 s = proclist_lock_write();
845 LIST_REMOVE(p, p_list); /* off zombproc */
846 p->p_pptr->p_nstopchild--;
847 LIST_REMOVE(p, p_sibling);
848 proclist_unlock_write(s);
849
850 /*
851 * Decrement the count of procs running with this uid.
852 */
853 (void)chgproccnt(kauth_cred_getuid(p->p_cred), -1);
854
855 /*
856 * Free up credentials.
857 */
858 kauth_cred_free(p->p_cred);
859
860 /*
861 * Release reference to text vnode
862 */
863 if (p->p_textvp)
864 vrele(p->p_textvp);
865
866 /* Release any SA state. */
867 if (p->p_sa)
868 sa_release(p);
869
870 /* Release remaining substructures. */
871 limfree(p->p_limit);
872 pstatsfree(p->p_stats);
873
874 /* Free proc structure and let pid be reallocated */
875 proc_free_mem(p);
876 }
877
878 /*
879 * make process 'parent' the new parent of process 'child'.
880 *
881 * Must be called with proclist_lock_write() held.
882 */
883 void
884 proc_reparent(struct proc *child, struct proc *parent)
885 {
886
887 if (child->p_pptr == parent)
888 return;
889
890 if (child->p_stat == SZOMB
891 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) {
892 child->p_pptr->p_nstopchild--;
893 parent->p_nstopchild++;
894 }
895 if (parent == initproc)
896 child->p_exitsig = SIGCHLD;
897
898 LIST_REMOVE(child, p_sibling);
899 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
900 child->p_pptr = parent;
901 }
Cache object: 1926420b60f94bf8f3749120b407d95a
|