FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
1 /* $NetBSD: kern_exit.c,v 1.139 2004/03/14 01:08:47 cl 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 1.139 2004/03/14 01:08:47 cl 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/proc.h>
88 #include <sys/tty.h>
89 #include <sys/time.h>
90 #include <sys/resource.h>
91 #include <sys/kernel.h>
92 #include <sys/ktrace.h>
93 #include <sys/proc.h>
94 #include <sys/buf.h>
95 #include <sys/wait.h>
96 #include <sys/file.h>
97 #include <sys/vnode.h>
98 #include <sys/syslog.h>
99 #include <sys/malloc.h>
100 #include <sys/pool.h>
101 #include <sys/resourcevar.h>
102 #if defined(PERFCTRS)
103 #include <sys/pmc.h>
104 #endif
105 #include <sys/ptrace.h>
106 #include <sys/acct.h>
107 #include <sys/filedesc.h>
108 #include <sys/ras.h>
109 #include <sys/signalvar.h>
110 #include <sys/sched.h>
111 #include <sys/sa.h>
112 #include <sys/savar.h>
113 #include <sys/mount.h>
114 #include <sys/syscallargs.h>
115 #include <sys/systrace.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 static void exit_psignal(struct proc *, struct proc *);
132
133 /*
134 * Fill in the appropriate signal information, and signal the parent.
135 */
136 static void
137 exit_psignal(struct proc *p, struct proc *pp)
138 {
139 ksiginfo_t ksi;
140
141 (void)memset(&ksi, 0, sizeof(ksi));
142 if ((ksi.ksi_signo = P_EXITSIG(p)) == SIGCHLD) {
143 if (WIFSIGNALED(p->p_xstat)) {
144 if (WCOREDUMP(p->p_xstat))
145 ksi.ksi_code = CLD_DUMPED;
146 else
147 ksi.ksi_code = CLD_KILLED;
148 } else {
149 ksi.ksi_code = CLD_EXITED;
150 }
151 }
152 /*
153 * we fill those in, even for non-SIGCHLD.
154 */
155 ksi.ksi_pid = p->p_pid;
156 ksi.ksi_uid = p->p_ucred->cr_uid;
157 ksi.ksi_status = p->p_xstat;
158 /* XXX: is this still valid? */
159 ksi.ksi_utime = p->p_ru->ru_utime.tv_sec;
160 ksi.ksi_stime = p->p_ru->ru_stime.tv_sec;
161 kpsignal(pp, &ksi, NULL);
162 }
163
164 /*
165 * exit --
166 * Death of process.
167 */
168 int
169 sys_exit(struct lwp *l, void *v, register_t *retval)
170 {
171 struct sys_exit_args /* {
172 syscallarg(int) rval;
173 } */ *uap = v;
174
175 /* Don't call exit1() multiple times in the same process.*/
176 if (l->l_proc->p_flag & P_WEXIT)
177 lwp_exit(l);
178
179 exit1(l, W_EXITCODE(SCARG(uap, rval), 0));
180 /* NOTREACHED */
181 return (0);
182 }
183
184 /*
185 * Exit: deallocate address space and other resources, change proc state
186 * to zombie, and unlink proc from allproc and parent's lists. Save exit
187 * status and rusage for wait(). Check for child processes and orphan them.
188 */
189 void
190 exit1(struct lwp *l, int rv)
191 {
192 struct proc *p, *q, *nq;
193 int s, sa;
194
195 p = l->l_proc;
196
197 if (__predict_false(p == initproc))
198 panic("init died (signal %d, exit %d)",
199 WTERMSIG(rv), WEXITSTATUS(rv));
200
201 p->p_flag |= P_WEXIT;
202 if (p->p_flag & P_STOPEXIT) {
203 int s;
204
205 sigminusset(&contsigmask, &p->p_sigctx.ps_siglist);
206 SCHED_LOCK(s);
207 p->p_stat = SSTOP;
208 l->l_stat = LSSTOP;
209 p->p_nrlwps--;
210 mi_switch(l, NULL);
211 SCHED_ASSERT_UNLOCKED();
212 splx(s);
213 }
214
215 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid));
216 /*
217 * Disable scheduler activation upcalls.
218 * We're trying to get out of here.
219 */
220 sa = 0;
221 if (p->p_sa != NULL) {
222 l->l_flag &= ~L_SA;
223 #if 0
224 p->p_flag &= ~P_SA;
225 #endif
226 sa = 1;
227 }
228
229 #ifdef PGINPROF
230 vmsizmon();
231 #endif
232 if (p->p_flag & P_PROFIL)
233 stopprofclock(p);
234 p->p_ru = pool_get(&rusage_pool, PR_WAITOK);
235 /*
236 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we
237 * wake up the parent early to avoid deadlock.
238 */
239 if (p->p_flag & P_PPWAIT) {
240 p->p_flag &= ~P_PPWAIT;
241 wakeup(p->p_pptr);
242 }
243 sigfillset(&p->p_sigctx.ps_sigignore);
244 sigemptyset(&p->p_sigctx.ps_siglist);
245 p->p_sigctx.ps_sigcheck = 0;
246 timers_free(p, TIMERS_ALL);
247
248 if (sa || (p->p_nlwps > 1)) {
249 exit_lwps(l);
250
251 /*
252 * Collect thread u-areas.
253 */
254 uvm_uarea_drain(FALSE);
255 }
256
257 #if defined(__HAVE_RAS)
258 ras_purgeall(p);
259 #endif
260
261 /*
262 * Close open files and release open-file table.
263 * This may block!
264 */
265 fdfree(p);
266 cwdfree(p);
267
268 doexithooks(p);
269
270 if (SESS_LEADER(p)) {
271 struct session *sp = p->p_session;
272 struct tty *tp;
273
274 if (sp->s_ttyvp) {
275 int s;
276 /*
277 * Controlling process.
278 * Signal foreground pgrp,
279 * drain controlling terminal
280 * and revoke access to controlling terminal.
281 */
282 tp = sp->s_ttyp;
283 s = spltty();
284 TTY_LOCK(tp);
285 if (tp->t_session == sp) {
286 if (tp->t_pgrp)
287 pgsignal(tp->t_pgrp, SIGHUP, 1);
288 /* we can't guarantee the revoke will do this */
289 tp->t_pgrp = NULL;
290 tp->t_session = NULL;
291 TTY_UNLOCK(tp);
292 splx(s);
293 SESSRELE(sp);
294 (void) ttywait(tp);
295 /*
296 * The tty could have been revoked
297 * if we blocked.
298 */
299 if (sp->s_ttyvp)
300 VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
301 } else {
302 TTY_UNLOCK(tp);
303 splx(s);
304 }
305 if (sp->s_ttyvp)
306 vrele(sp->s_ttyvp);
307 sp->s_ttyvp = NULL;
308 /*
309 * s_ttyp is not zero'd; we use this to indicate
310 * that the session once had a controlling terminal.
311 * (for logging and informational purposes)
312 */
313 }
314 sp->s_leader = NULL;
315 }
316 fixjobc(p, p->p_pgrp, 0);
317 (void)acct_process(p);
318 #ifdef KTRACE
319 /*
320 * release trace file
321 */
322 ktrderef(p);
323 #endif
324 #ifdef SYSTRACE
325 systrace_sys_exit(p);
326 #endif
327 /*
328 * If emulation has process exit hook, call it now.
329 */
330 if (p->p_emul->e_proc_exit)
331 (*p->p_emul->e_proc_exit)(p);
332
333 /*
334 * Reset p_opptr pointer of all former children which got
335 * traced by another process and were reparented. We reset
336 * it to NULL here; the trace detach code then reparents
337 * the child to initproc. We only check allproc list, since
338 * eventual former children on zombproc list won't reference
339 * p_opptr anymore.
340 */
341 s = proclist_lock_write();
342 if (p->p_flag & P_CHTRACED) {
343 LIST_FOREACH(q, &allproc, p_list) {
344 if (q->p_opptr == p)
345 q->p_opptr = NULL;
346 }
347 }
348
349 /*
350 * Give orphaned children to init(8).
351 */
352 q = LIST_FIRST(&p->p_children);
353 if (q) /* only need this if any child is SZOMB */
354 wakeup(initproc);
355 for (; q != NULL; q = nq) {
356 nq = LIST_NEXT(q, p_sibling);
357
358 /*
359 * Traced processes are killed since their existence
360 * means someone is screwing up. Since we reset the
361 * trace flags, the logic in sys_wait4() would not be
362 * triggered to reparent the process to its
363 * original parent, so we must do this here.
364 */
365 if (q->p_flag & P_TRACED) {
366 if (q->p_opptr != q->p_pptr) {
367 struct proc *t = q->p_opptr;
368 proc_reparent(q, t ? t : initproc);
369 q->p_opptr = NULL;
370 } else
371 proc_reparent(q, initproc);
372 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE);
373 psignal(q, SIGKILL);
374 } else {
375 proc_reparent(q, initproc);
376 }
377 }
378 proclist_unlock_write(s);
379
380 /*
381 * Free the VM resources we're still holding on to.
382 * We must do this from a valid thread because doing
383 * so may block. This frees vmspace, which we don't
384 * need anymore. The only remaining lwp is the one
385 * we run at this moment, nothing runs in userland
386 * anymore.
387 */
388 uvm_proc_exit(p);
389
390 /*
391 * Give machine-dependent code a chance to free any
392 * MD LWP resources while we can still block. This must be done
393 * before uvm_lwp_exit(), in case these resources are in the
394 * PCB.
395 * THIS IS LAST BLOCKING OPERATION.
396 */
397 #ifndef __NO_CPU_LWP_FREE
398 cpu_lwp_free(l, 1);
399 #endif
400
401 pmap_deactivate(l);
402
403 /*
404 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP!
405 */
406
407 /*
408 * Save exit status and final rusage info, adding in child rusage
409 * info and self times.
410 * In order to pick up the time for the current execution, we must
411 * do this before unlinking the lwp from l_list.
412 */
413 p->p_xstat = rv;
414 *p->p_ru = p->p_stats->p_ru;
415 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
416 ruadd(p->p_ru, &p->p_stats->p_cru);
417
418 /*
419 * Move proc from allproc to zombproc, it's now ready
420 * to be collected by parent. Remaining lwp resources
421 * will be freed in lwp_exit2() once we'd switch to idle
422 * context.
423 * Changing the state to SZOMB stops it being found by pfind().
424 */
425 s = proclist_lock_write();
426 LIST_REMOVE(p, p_list);
427 LIST_INSERT_HEAD(&zombproc, p, p_list);
428 p->p_stat = SZOMB;
429
430 LIST_REMOVE(l, l_list);
431 LIST_REMOVE(l, l_sibling);
432 l->l_flag |= L_DETACHED|L_PROCEXIT; /* detached from proc too */
433 l->l_stat = LSDEAD;
434
435 p->p_nrlwps--;
436 p->p_nlwps--;
437
438 /* Put in front of parent's sibling list for parent to collect it */
439 q = p->p_pptr;
440 q->p_nstopchild++;
441 if (LIST_FIRST(&q->p_children) != p) {
442 /* Put child where it can be found quickly */
443 LIST_REMOVE(p, p_sibling);
444 LIST_INSERT_HEAD(&q->p_children, p, p_sibling);
445 }
446
447 proclist_unlock_write(s);
448
449 /*
450 * Notify interested parties of our demise.
451 */
452 KNOTE(&p->p_klist, NOTE_EXIT);
453
454 #if PERFCTRS
455 /*
456 * Save final PMC information in parent process & clean up.
457 */
458 if (PMC_ENABLED(p)) {
459 pmc_save_context(p);
460 pmc_accumulate(p->p_pptr, p);
461 pmc_process_exit(p);
462 }
463 #endif
464
465 /*
466 * Notify parent that we're gone. If parent has the P_NOCLDWAIT
467 * flag set, notify init instead (and hope it will handle
468 * this situation).
469 */
470 if (p->p_pptr->p_flag & P_NOCLDWAIT) {
471 struct proc *pp = p->p_pptr;
472 proc_reparent(p, initproc);
473
474 /*
475 * If this was the last child of our parent, notify
476 * parent, so in case he was wait(2)ing, he will
477 * continue.
478 */
479 if (LIST_FIRST(&pp->p_children) == NULL)
480 wakeup(pp);
481 }
482
483 /* Wake up the parent so it can get exit status. */
484 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0)
485 exit_psignal(p, p->p_pptr);
486 wakeup(p->p_pptr);
487
488 /*
489 * Release the process's signal state.
490 */
491 sigactsfree(p);
492
493 /*
494 * Clear curlwp after we've done all operations
495 * that could block, and before tearing down the rest
496 * of the process state that might be used from clock, etc.
497 * Also, can't clear curlwp while we're still runnable,
498 * as we're not on a run queue (we are current, just not
499 * a proper proc any longer!).
500 *
501 * Other substructures are freed from wait().
502 */
503 curlwp = NULL;
504 limfree(p->p_limit);
505 pstatsfree(p->p_stats);
506 p->p_limit = NULL;
507
508 /* This process no longer needs to hold the kernel lock. */
509 KERNEL_PROC_UNLOCK(l);
510
511 #ifdef DEBUG
512 /* Nothing should use the process link anymore */
513 l->l_proc = NULL;
514 #endif
515
516 /*
517 * Finally, call machine-dependent code to switch to a new
518 * context (possibly the idle context). Once we are no longer
519 * using the dead lwp's stack, lwp_exit2() will be called
520 * to arrange for the resources to be released.
521 *
522 * Note that cpu_exit() will end with a call equivalent to
523 * cpu_switch(), finishing our execution (pun intended).
524 */
525
526 uvmexp.swtch++;
527 cpu_exit(l);
528 }
529
530 void
531 exit_lwps(struct lwp *l)
532 {
533 struct proc *p;
534 struct lwp *l2;
535 struct sadata_vp *vp;
536 int s, error;
537 lwpid_t waited;
538
539 p = l->l_proc;
540
541 /* XXX SMP
542 * This would be the right place to IPI any LWPs running on
543 * other processors so that they can notice the userret exit hook.
544 */
545 p->p_userret = lwp_exit_hook;
546 p->p_userret_arg = NULL;
547
548 if (p->p_sa) {
549 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) {
550 /*
551 * Make SA-cached LWPs normal process runnable
552 * LWPs so that they'll also self-destruct.
553 */
554 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ",
555 p->p_pid, vp->savp_id));
556 SCHED_LOCK(s);
557 while ((l2 = sa_getcachelwp(vp)) != 0) {
558 l2->l_priority = l2->l_usrpri;
559 setrunnable(l2);
560 DPRINTF(("%d ", l2->l_lid));
561 }
562 SCHED_UNLOCK(s);
563 DPRINTF(("\n"));
564
565 /*
566 * Clear wokenq, the LWPs on the queue will
567 * run below.
568 */
569 vp->savp_wokenq_head = NULL;
570 }
571 }
572
573 /*
574 * Interrupt LWPs in interruptable sleep, unsuspend suspended
575 * LWPs, make detached LWPs undetached (so we can wait for
576 * them) and then wait for everyone else to finish.
577 */
578 LIST_FOREACH(l2, &p->p_lwps, l_sibling) {
579 l2->l_flag &= ~(L_DETACHED|L_SA);
580
581 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) ||
582 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) {
583 SCHED_LOCK(s);
584 setrunnable(l2);
585 SCHED_UNLOCK(s);
586 DPRINTF(("exit_lwps: Made %d.%d runnable\n",
587 p->p_pid, l2->l_lid));
588 }
589 }
590
591
592 while (p->p_nlwps > 1) {
593 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n",
594 p->p_nlwps, p->p_nrlwps, p->p_nzlwps));
595 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL);
596 if (error)
597 panic("exit_lwps: lwp_wait1 failed with error %d\n",
598 error);
599 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited));
600 }
601
602 p->p_userret = NULL;
603 }
604
605 /* Wrapper function for use in p_userret */
606 static void
607 lwp_exit_hook(struct lwp *l, void *arg)
608 {
609 KERNEL_PROC_LOCK(l);
610 lwp_exit(l);
611 }
612
613 int
614 sys_wait4(struct lwp *l, void *v, register_t *retval)
615 {
616 struct sys_wait4_args /* {
617 syscallarg(int) pid;
618 syscallarg(int *) status;
619 syscallarg(int) options;
620 syscallarg(struct rusage *) rusage;
621 } */ *uap = v;
622 struct proc *child, *parent;
623 int status, error;
624
625 parent = l->l_proc;
626
627 if (SCARG(uap, pid) == 0)
628 SCARG(uap, pid) = -parent->p_pgid;
629 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG))
630 return (EINVAL);
631
632 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options),
633 &child);
634 if (error != 0)
635 return error;
636 if (child == NULL) {
637 *retval = 0;
638 return 0;
639 }
640
641 /*
642 * Collect child u-areas.
643 */
644 uvm_uarea_drain(FALSE);
645
646 retval[0] = child->p_pid;
647
648 if (child->p_stat == SZOMB) {
649 if (SCARG(uap, status)) {
650 status = child->p_xstat; /* convert to int */
651 error = copyout(&status, SCARG(uap, status),
652 sizeof(status));
653 if (error)
654 return (error);
655 }
656 if (SCARG(uap, rusage)) {
657 error = copyout(child->p_ru, SCARG(uap, rusage),
658 sizeof(struct rusage));
659 if (error)
660 return (error);
661 }
662
663 proc_free(child);
664 return 0;
665 }
666
667 /* child state must be SSTOP */
668 if (SCARG(uap, status)) {
669 status = W_STOPCODE(child->p_xstat);
670 return copyout(&status, SCARG(uap, status), sizeof(status));
671 }
672 return 0;
673 }
674
675 /*
676 * Scan list of child processes for a child process that has stopped or
677 * exited. Used by sys_wait4 and 'compat' equivalents.
678 */
679 int
680 find_stopped_child(struct proc *parent, pid_t pid, int options,
681 struct proc **child_p)
682 {
683 struct proc *child;
684 int error;
685
686 for (;;) {
687 proclist_lock_read();
688 error = ECHILD;
689 LIST_FOREACH(child, &parent->p_children, p_sibling) {
690 if (pid >= 0) {
691 if (child->p_pid != pid) {
692 child = p_find(pid, PFIND_ZOMBIE |
693 PFIND_LOCKED);
694 if (child == NULL
695 || child->p_pptr != parent) {
696 child = NULL;
697 break;
698 }
699 }
700 } else
701 if (pid != WAIT_ANY && child->p_pgid != -pid)
702 /* child not in correct pgrp */
703 continue;
704 /*
705 * Wait for processes with p_exitsig != SIGCHLD
706 * processes only if WALTSIG is set; wait for
707 * processes with p_exitsig == SIGCHLD only
708 * if WALTSIG is clear.
709 */
710 if (((options & WALLSIG) == 0) &&
711 (options & WALTSIG ? child->p_exitsig == SIGCHLD
712 : P_EXITSIG(child) != SIGCHLD)){
713 if (child->p_pid == pid) {
714 child = NULL;
715 break;
716 }
717 continue;
718 }
719
720 error = 0;
721 if (child->p_stat == SZOMB && !(options & WNOZOMBIE))
722 break;
723
724 if (child->p_stat == SSTOP &&
725 (child->p_flag & P_WAITED) == 0 &&
726 (child->p_flag & P_TRACED || options & WUNTRACED)) {
727 if ((options & WNOWAIT) == 0) {
728 child->p_flag |= P_WAITED;
729 parent->p_nstopchild--;
730 }
731 break;
732 }
733 if (parent->p_nstopchild == 0 || child->p_pid == pid) {
734 child = NULL;
735 break;
736 }
737 }
738 proclist_unlock_read();
739 if (child != NULL || error != 0 || options & WNOHANG) {
740 *child_p = child;
741 return error;
742 }
743 error = tsleep(parent, PWAIT | PCATCH, "wait", 0);
744 if (error != 0)
745 return error;
746 }
747 }
748
749 /*
750 * Free a process after parent has taken all the state info.
751 */
752 void
753 proc_free(struct proc *p)
754 {
755 struct proc *parent = p->p_pptr;
756 int s;
757
758 KASSERT(p->p_nlwps == 0);
759 KASSERT(p->p_nzlwps == 0);
760 KASSERT(p->p_nrlwps == 0);
761 KASSERT(LIST_EMPTY(&p->p_lwps));
762
763 /*
764 * If we got the child via ptrace(2) or procfs, and
765 * the parent is different (meaning the process was
766 * attached, rather than run as a child), then we need
767 * to give it back to the old parent, and send the
768 * parent the exit signal. The rest of the cleanup
769 * will be done when the old parent waits on the child.
770 */
771 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){
772 parent = p->p_opptr;
773 if (parent == NULL)
774 parent = initproc;
775 proc_reparent(p, parent);
776 p->p_opptr = NULL;
777 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE);
778 if (p->p_exitsig != 0)
779 exit_psignal(p, parent);
780 wakeup(parent);
781 return;
782 }
783
784 scheduler_wait_hook(parent, p);
785 p->p_xstat = 0;
786
787 ruadd(&parent->p_stats->p_cru, p->p_ru);
788
789 /*
790 * At this point we are going to start freeing the final resources.
791 * If anyone tries to access the proc structure after here they
792 * will get a shock - bits are missing.
793 * Attempt to make it hard!
794 */
795
796 p->p_stat = SIDL; /* not even a zombie any more */
797
798 pool_put(&rusage_pool, p->p_ru);
799
800 /*
801 * Finally finished with old proc entry.
802 * Unlink it from its process group and free it.
803 */
804 leavepgrp(p);
805
806 s = proclist_lock_write();
807 LIST_REMOVE(p, p_list); /* off zombproc */
808 p->p_pptr->p_nstopchild--;
809 LIST_REMOVE(p, p_sibling);
810 proclist_unlock_write(s);
811
812 /*
813 * Decrement the count of procs running with this uid.
814 */
815 (void)chgproccnt(p->p_cred->p_ruid, -1);
816
817 /*
818 * Free up credentials.
819 */
820 if (--p->p_cred->p_refcnt == 0) {
821 crfree(p->p_cred->pc_ucred);
822 pool_put(&pcred_pool, p->p_cred);
823 }
824
825 /*
826 * Release reference to text vnode
827 */
828 if (p->p_textvp)
829 vrele(p->p_textvp);
830
831 /* Release any SA state. */
832 if (p->p_sa)
833 sa_release(p);
834
835 /* Free proc structure and let pid be reallocated */
836 proc_free_mem(p);
837 }
838
839 /*
840 * make process 'parent' the new parent of process 'child'.
841 *
842 * Must be called with proclist_lock_write() held.
843 */
844 void
845 proc_reparent(struct proc *child, struct proc *parent)
846 {
847
848 if (child->p_pptr == parent)
849 return;
850
851 if (child->p_stat == SZOMB
852 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) {
853 child->p_pptr->p_nstopchild--;
854 parent->p_nstopchild++;
855 }
856 if (parent == initproc)
857 child->p_exitsig = SIGCHLD;
858
859 LIST_REMOVE(child, p_sibling);
860 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
861 child->p_pptr = parent;
862 }
Cache object: 90621e77415cceb19b55425633bab6b0
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