2 * Copyright (c) 1982, 1986, 1989, 1991, 1993
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4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
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34 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include "opt_compat.h"
41 #include "opt_kdtrace.h"
42 #include "opt_ktrace.h"
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/sysproto.h>
47 #include <sys/eventhandler.h>
48 #include <sys/kernel.h>
49 #include <sys/malloc.h>
51 #include <sys/mutex.h>
53 #include <sys/pioctl.h>
57 #include <sys/vmmeter.h>
58 #include <sys/vnode.h>
59 #include <sys/resourcevar.h>
61 #include <sys/signalvar.h>
62 #include <sys/sched.h>
64 #include <sys/syscallsubr.h>
65 #include <sys/syslog.h>
66 #include <sys/ptrace.h>
67 #include <sys/acct.h> /* for acct_process() function prototype */
68 #include <sys/filedesc.h>
73 #include <sys/ktrace.h>
76 #include <security/audit/audit.h>
77 #include <security/mac/mac_framework.h>
80 #include <vm/vm_extern.h>
81 #include <vm/vm_param.h>
83 #include <vm/vm_map.h>
84 #include <vm/vm_page.h>
88 #include <sys/dtrace_bsd.h>
89 dtrace_execexit_func_t dtrace_fasttrap_exit;
92 SDT_PROVIDER_DECLARE(proc);
93 SDT_PROBE_DEFINE(proc, kernel, , exit);
94 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int");
96 /* Required to be non-static for SysVR4 emulator */
97 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
99 /* Hook for NFS teardown procedure. */
100 void (*nlminfo_release_p)(struct proc *p);
103 * exit -- death of process.
106 sys_exit(struct thread *td, struct sys_exit_args *uap)
109 exit1(td, W_EXITCODE(uap->rval, 0));
114 * Exit: deallocate address space and other resources, change proc state to
115 * zombie, and unlink proc from allproc and parent's lists. Save exit status
116 * and rusage for wait(). Check for child processes and orphan them.
119 exit1(struct thread *td, int rv)
121 struct proc *p, *nq, *q;
123 struct vnode *ttyvp = NULL;
125 struct vnode *tracevp;
126 struct ucred *tracecred;
131 mtx_assert(&Giant, MA_NOTOWNED);
135 * XXX in case we're rebooting we just let init die in order to
136 * work around an unsolved stack overflow seen very late during
137 * shutdown on sparc64 when the gmirror worker process exists.
139 if (p == initproc && rebooting == 0) {
140 printf("init died (signal %d, exit %d)\n",
141 WTERMSIG(rv), WEXITSTATUS(rv));
142 panic("Going nowhere without my init!");
146 * MUST abort all other threads before proceeding past here.
149 while (p->p_flag & P_HADTHREADS) {
151 * First check if some other thread got here before us..
152 * if so, act apropriatly, (exit or suspend);
154 thread_suspend_check(0);
157 * Kill off the other threads. This requires
158 * some co-operation from other parts of the kernel
159 * so it may not be instantaneous. With this state set
160 * any thread entering the kernel from userspace will
161 * thread_exit() in trap(). Any thread attempting to
162 * sleep will return immediately with EINTR or EWOULDBLOCK
163 * which will hopefully force them to back out to userland
164 * freeing resources as they go. Any thread attempting
165 * to return to userland will thread_exit() from userret().
166 * thread_exit() will unsuspend us when the last of the
167 * other threads exits.
168 * If there is already a thread singler after resumption,
169 * calling thread_single will fail; in that case, we just
170 * re-check all suspension request, the thread should
171 * either be suspended there or exit.
173 if (! thread_single(SINGLE_EXIT))
177 * All other activity in this process is now stopped.
178 * Threading support has been turned off.
181 KASSERT(p->p_numthreads == 1,
182 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
184 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
185 * on our vmspace, so we should block below until they have
186 * released their reference to us. Note that if they have
187 * requested S_EXIT stops we will block here until they ack
190 _STOPEVENT(p, S_EXIT, rv);
193 * Note that we are exiting and do another wakeup of anyone in
194 * PIOCWAIT in case they aren't listening for S_EXIT stops or
195 * decided to wait again after we told them we are exiting.
197 p->p_flag |= P_WEXIT;
201 * Wait for any processes that have a hold on our vmspace to
202 * release their reference.
204 while (p->p_lock > 0)
205 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
208 /* Drain the limit callout while we don't have the proc locked */
209 callout_drain(&p->p_limco);
213 * The Sun BSM exit token contains two components: an exit status as
214 * passed to exit(), and a return value to indicate what sort of exit
215 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
216 * what the return value is.
218 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0);
219 AUDIT_SYSCALL_EXIT(0, td);
222 /* Are we a task leader? */
223 if (p == p->p_leader) {
224 mtx_lock(&ppeers_lock);
232 while (p->p_peers != NULL)
233 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
234 mtx_unlock(&ppeers_lock);
238 * Check if any loadable modules need anything done at process exit.
239 * E.g. SYSV IPC stuff
240 * XXX what if one of these generates an error?
242 EVENTHANDLER_INVOKE(process_exit, p);
245 * If parent is waiting for us to exit or exec,
246 * P_PPWAIT is set; we will wakeup the parent below.
250 p->p_flag &= ~(P_TRACED | P_PPWAIT);
253 * Stop the real interval timer. If the handler is currently
254 * executing, prevent it from rearming itself and let it finish.
256 if (timevalisset(&p->p_realtimer.it_value) &&
257 callout_stop(&p->p_itcallout) == 0) {
258 timevalclear(&p->p_realtimer.it_interval);
259 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
260 KASSERT(!timevalisset(&p->p_realtimer.it_value),
261 ("realtime timer is still armed"));
266 * Reset any sigio structures pointing to us as a result of
267 * F_SETOWN with our pid.
269 funsetownlst(&p->p_sigiolst);
272 * If this process has an nlminfo data area (for lockd), release it
274 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
275 (*nlminfo_release_p)(p);
278 * Close open files and release open-file table.
284 * If this thread tickled GEOM, we need to wait for the giggling to
285 * stop before we return to userland
287 if (td->td_pflags & TDP_GEOM)
291 * Remove ourself from our leader's peer list and wake our leader.
293 mtx_lock(&ppeers_lock);
294 if (p->p_leader->p_peers) {
296 while (q->p_peers != p)
298 q->p_peers = p->p_peers;
301 mtx_unlock(&ppeers_lock);
305 sx_xlock(&proctree_lock);
306 if (SESS_LEADER(p)) {
307 struct session *sp = p->p_session;
311 * s_ttyp is not zero'd; we use this to indicate that
312 * the session once had a controlling terminal. (for
313 * logging and informational purposes)
323 * Signal foreground pgrp and revoke access to
324 * controlling terminal if it has not been revoked
327 * Because the TTY may have been revoked in the mean
328 * time and could already have a new session associated
329 * with it, make sure we don't send a SIGHUP to a
330 * foreground process group that does not belong to this
336 if (tp->t_session == sp)
337 tty_signal_pgrp(tp, SIGHUP);
342 sx_xunlock(&proctree_lock);
343 if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) {
344 VOP_REVOKE(ttyvp, REVOKEALL);
345 VOP_UNLOCK(ttyvp, 0);
347 sx_xlock(&proctree_lock);
350 fixjobc(p, p->p_pgrp, 0);
351 sx_xunlock(&proctree_lock);
352 (void)acct_process(td);
354 /* Release the TTY now we've unlocked everything. */
359 * Disable tracing, then drain any pending records and release
362 if (p->p_traceflag != 0) {
364 mtx_lock(&ktrace_mtx);
366 mtx_unlock(&ktrace_mtx);
370 mtx_lock(&ktrace_mtx);
371 tracevp = p->p_tracevp;
373 tracecred = p->p_tracecred;
374 p->p_tracecred = NULL;
375 mtx_unlock(&ktrace_mtx);
377 if (tracevp != NULL) {
378 locked = VFS_LOCK_GIANT(tracevp->v_mount);
380 VFS_UNLOCK_GIANT(locked);
382 if (tracecred != NULL)
387 * Release reference to text vnode
389 if ((vtmp = p->p_textvp) != NULL) {
391 locked = VFS_LOCK_GIANT(vtmp->v_mount);
393 VFS_UNLOCK_GIANT(locked);
397 * Release our limits structure.
406 * Remove proc from allproc queue and pidhash chain.
407 * Place onto zombproc. Unlink from parent's child list.
409 sx_xlock(&allproc_lock);
410 LIST_REMOVE(p, p_list);
411 LIST_INSERT_HEAD(&zombproc, p, p_list);
412 LIST_REMOVE(p, p_hash);
413 sx_xunlock(&allproc_lock);
416 * Call machine-dependent code to release any
417 * machine-dependent resources other than the address space.
418 * The address space is released by "vmspace_exitfree(p)" in
423 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
426 * Reparent all of our children to init.
428 sx_xlock(&proctree_lock);
429 q = LIST_FIRST(&p->p_children);
430 if (q != NULL) /* only need this if any child is S_ZOMB */
432 for (; q != NULL; q = nq) {
433 nq = LIST_NEXT(q, p_sibling);
435 proc_reparent(q, initproc);
436 q->p_sigparent = SIGCHLD;
438 * Traced processes are killed
439 * since their existence means someone is screwing up.
441 if (q->p_flag & P_TRACED) {
444 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
445 FOREACH_THREAD_IN_PROC(q, temp)
446 temp->td_dbgflags &= ~TDB_SUSPEND;
452 /* Save exit status. */
457 /* Tell the prison that we are gone. */
458 prison_proc_free(p->p_ucred->cr_prison);
462 * Tell the DTrace fasttrap provider about the exit if it
463 * has declared an interest.
465 if (dtrace_fasttrap_exit)
466 dtrace_fasttrap_exit(p);
470 * Notify interested parties of our demise.
472 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
475 int reason = CLD_EXITED;
478 else if (WIFSIGNALED(rv))
480 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0);
484 * Just delete all entries in the p_klist. At this point we won't
485 * report any more events, and there are nasty race conditions that
486 * can beat us if we don't.
488 knlist_clear(&p->p_klist, 1);
491 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
492 * flag set, or if the handler is set to SIG_IGN, notify process
493 * 1 instead (and hope it will handle this situation).
495 PROC_LOCK(p->p_pptr);
496 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
497 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
500 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
503 proc_reparent(p, initproc);
504 p->p_sigparent = SIGCHLD;
505 PROC_LOCK(p->p_pptr);
508 * Notify parent, so in case he was wait(2)ing or
509 * executing waitpid(2) with our pid, he will
514 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
516 if (p->p_pptr == initproc)
517 psignal(p->p_pptr, SIGCHLD);
518 else if (p->p_sigparent != 0) {
519 if (p->p_sigparent == SIGCHLD)
521 else /* LINUX thread */
522 psignal(p->p_pptr, p->p_sigparent);
524 sx_xunlock(&proctree_lock);
527 * The state PRS_ZOMBIE prevents other proesses from sending
528 * signal to the process, to avoid memory leak, we free memory
529 * for signal queue at the time when the state is set.
531 sigqueue_flush(&p->p_sigqueue);
532 sigqueue_flush(&td->td_sigqueue);
535 * We have to wait until after acquiring all locks before
536 * changing p_state. We need to avoid all possible context
537 * switches (including ones from blocking on a mutex) while
538 * marked as a zombie. We also have to set the zombie state
539 * before we release the parent process' proc lock to avoid
540 * a lost wakeup. So, we first call wakeup, then we grab the
541 * sched lock, update the state, and release the parent process'
545 cv_broadcast(&p->p_pwait);
546 sched_exit(p->p_pptr, td);
548 p->p_state = PRS_ZOMBIE;
549 PROC_UNLOCK(p->p_pptr);
552 * Hopefully no one will try to deliver a signal to the process this
555 knlist_destroy(&p->p_klist);
558 * Save our children's rusage information in our exit rusage.
560 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
563 * Make sure the scheduler takes this thread out of its tables etc.
564 * This will also release this thread's reference to the ucred.
565 * Other thread parts to release include pcb bits and such.
571 #ifndef _SYS_SYSPROTO_H_
580 abort2(struct thread *td, struct abort2_args *uap)
582 struct proc *p = td->td_proc;
588 * Do it right now so we can log either proper call of abort2(), or
589 * note, that invalid argument was passed. 512 is big enough to
590 * handle 16 arguments' descriptions with additional comments.
592 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
594 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
595 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
597 * Since we can't return from abort2(), send SIGKILL in cases, where
598 * abort2() was called improperly
601 /* Prevent from DoSes from user-space. */
602 if (uap->nargs < 0 || uap->nargs > 16)
604 if (uap->nargs > 0) {
605 if (uap->args == NULL)
607 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
612 * Limit size of 'reason' string to 128. Will fit even when
613 * maximal number of arguments was chosen to be logged.
615 if (uap->why != NULL) {
616 error = sbuf_copyin(sb, uap->why, 128);
620 sbuf_printf(sb, "(null)");
622 if (uap->nargs > 0) {
623 sbuf_printf(sb, "(");
624 for (i = 0;i < uap->nargs; i++)
625 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
626 sbuf_printf(sb, ")");
629 * Final stage: arguments were proper, string has been
630 * successfully copied from userspace, and copying pointers
631 * from user-space succeed.
635 if (sig == SIGKILL) {
637 sbuf_printf(sb, " (Reason text inaccessible)");
641 log(LOG_INFO, "%s", sbuf_data(sb));
643 exit1(td, W_EXITCODE(0, sig));
650 * The dirty work is handled by kern_wait().
653 owait(struct thread *td, struct owait_args *uap __unused)
657 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
659 td->td_retval[1] = status;
662 #endif /* COMPAT_43 */
665 * The dirty work is handled by kern_wait().
668 wait4(struct thread *td, struct wait_args *uap)
670 struct rusage ru, *rup;
673 if (uap->rusage != NULL)
677 error = kern_wait(td, uap->pid, &status, uap->options, rup);
678 if (uap->status != NULL && error == 0)
679 error = copyout(&status, uap->status, sizeof(status));
680 if (uap->rusage != NULL && error == 0)
681 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
686 * Reap the remains of a zombie process and optionally return status and
687 * rusage. Asserts and will release both the proctree_lock and the process
688 * lock as part of its work.
691 proc_reap(struct thread *td, struct proc *p, int *status, int options,
692 struct rusage *rusage)
696 sx_assert(&proctree_lock, SA_XLOCKED);
697 PROC_LOCK_ASSERT(p, MA_OWNED);
698 PROC_SLOCK_ASSERT(p, MA_OWNED);
699 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
704 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
707 td->td_retval[0] = p->p_pid;
709 *status = p->p_xstat; /* convert to int */
710 if (options & WNOWAIT) {
712 * Only poll, returning the status. Caller does not wish to
713 * release the proc struct just yet.
716 sx_xunlock(&proctree_lock);
721 sigqueue_take(p->p_ksi);
726 * If we got the child via a ptrace 'attach', we need to give it back
729 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
734 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
736 cv_broadcast(&p->p_pwait);
738 sx_xunlock(&proctree_lock);
743 * Remove other references to this process to ensure we have an
744 * exclusive reference.
746 sx_xlock(&allproc_lock);
747 LIST_REMOVE(p, p_list); /* off zombproc */
748 sx_xunlock(&allproc_lock);
749 LIST_REMOVE(p, p_sibling);
751 sx_xunlock(&proctree_lock);
754 * As a side effect of this lock, we know that all other writes to
755 * this proc are visible now, so no more locking is needed for p.
758 p->p_xstat = 0; /* XXX: why? */
761 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
765 * Decrement the count of procs running with this uid.
767 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
770 * Free credentials, arguments, and sigacts.
774 pargs_drop(p->p_args);
776 sigacts_free(p->p_sigacts);
780 * Do any thread-system specific cleanups.
785 * Give vm and machine-dependent layer a chance to free anything that
786 * cpu_exit couldn't release while still running in process context.
792 KASSERT(FIRST_THREAD_IN_PROC(p),
793 ("proc_reap: no residual thread!"));
794 uma_zfree(proc_zone, p);
795 sx_xlock(&allproc_lock);
797 sx_xunlock(&allproc_lock);
801 kern_wait(struct thread *td, pid_t pid, int *status, int options,
802 struct rusage *rusage)
808 AUDIT_ARG_VALUE(options);
816 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE))
819 if (q->p_flag & P_STATCHILD) {
821 q->p_flag &= ~P_STATCHILD;
825 sx_xlock(&proctree_lock);
826 LIST_FOREACH(p, &q->p_children, p_sibling) {
828 if (pid != WAIT_ANY &&
829 p->p_pid != pid && p->p_pgid != -pid) {
833 if (p_canwait(td, p)) {
839 * This special case handles a kthread spawned by linux_clone
840 * (see linux_misc.c). The linux_wait4 and linux_waitpid
841 * functions need to be able to distinguish between waiting
842 * on a process and waiting on a thread. It is a thread if
843 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
844 * signifies we want to wait for threads and not processes.
846 if ((p->p_sigparent != SIGCHLD) ^
847 ((options & WLINUXCLONE) != 0)) {
854 if (p->p_state == PRS_ZOMBIE) {
855 proc_reap(td, p, status, options, rusage);
858 if ((p->p_flag & P_STOPPED_SIG) &&
859 (p->p_suspcount == p->p_numthreads) &&
860 (p->p_flag & P_WAITED) == 0 &&
861 (p->p_flag & P_TRACED || options & WUNTRACED)) {
863 p->p_flag |= P_WAITED;
864 sx_xunlock(&proctree_lock);
865 td->td_retval[0] = p->p_pid;
867 *status = W_STOPCODE(p->p_xstat);
870 sigqueue_take(p->p_ksi);
877 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
878 sx_xunlock(&proctree_lock);
879 td->td_retval[0] = p->p_pid;
880 p->p_flag &= ~P_CONTINUED;
883 sigqueue_take(p->p_ksi);
894 sx_xunlock(&proctree_lock);
897 if (options & WNOHANG) {
898 sx_xunlock(&proctree_lock);
899 td->td_retval[0] = 0;
903 sx_xunlock(&proctree_lock);
904 if (q->p_flag & P_STATCHILD) {
905 q->p_flag &= ~P_STATCHILD;
908 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
916 * Make process 'parent' the new parent of process 'child'.
917 * Must be called with an exclusive hold of proctree lock.
920 proc_reparent(struct proc *child, struct proc *parent)
923 sx_assert(&proctree_lock, SX_XLOCKED);
924 PROC_LOCK_ASSERT(child, MA_OWNED);
925 if (child->p_pptr == parent)
928 PROC_LOCK(child->p_pptr);
929 sigqueue_take(child->p_ksi);
930 PROC_UNLOCK(child->p_pptr);
931 LIST_REMOVE(child, p_sibling);
932 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
933 child->p_pptr = parent;