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, exit);
94 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int");
96 /* Hook for NFS teardown procedure. */
97 void (*nlminfo_release_p)(struct proc *p);
100 * exit -- death of process.
103 sys_exit(struct thread *td, struct sys_exit_args *uap)
106 exit1(td, W_EXITCODE(uap->rval, 0));
111 * Exit: deallocate address space and other resources, change proc state to
112 * zombie, and unlink proc from allproc and parent's lists. Save exit status
113 * and rusage for wait(). Check for child processes and orphan them.
116 exit1(struct thread *td, int rv)
118 struct proc *p, *nq, *q;
120 struct vnode *ttyvp = NULL;
124 mtx_assert(&Giant, MA_NOTOWNED);
128 * XXX in case we're rebooting we just let init die in order to
129 * work around an unsolved stack overflow seen very late during
130 * shutdown on sparc64 when the gmirror worker process exists.
132 if (p == initproc && rebooting == 0) {
133 printf("init died (signal %d, exit %d)\n",
134 WTERMSIG(rv), WEXITSTATUS(rv));
135 panic("Going nowhere without my init!");
139 * MUST abort all other threads before proceeding past here.
142 while (p->p_flag & P_HADTHREADS) {
144 * First check if some other thread got here before us..
145 * if so, act apropriatly, (exit or suspend);
147 thread_suspend_check(0);
150 * Kill off the other threads. This requires
151 * some co-operation from other parts of the kernel
152 * so it may not be instantaneous. With this state set
153 * any thread entering the kernel from userspace will
154 * thread_exit() in trap(). Any thread attempting to
155 * sleep will return immediately with EINTR or EWOULDBLOCK
156 * which will hopefully force them to back out to userland
157 * freeing resources as they go. Any thread attempting
158 * to return to userland will thread_exit() from userret().
159 * thread_exit() will unsuspend us when the last of the
160 * other threads exits.
161 * If there is already a thread singler after resumption,
162 * calling thread_single will fail; in that case, we just
163 * re-check all suspension request, the thread should
164 * either be suspended there or exit.
166 if (! thread_single(SINGLE_EXIT))
170 * All other activity in this process is now stopped.
171 * Threading support has been turned off.
174 KASSERT(p->p_numthreads == 1,
175 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
177 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
178 * on our vmspace, so we should block below until they have
179 * released their reference to us. Note that if they have
180 * requested S_EXIT stops we will block here until they ack
183 _STOPEVENT(p, S_EXIT, rv);
186 * Ignore any pending request to stop due to a stop signal.
187 * Once P_WEXIT is set, future requests will be ignored as
190 p->p_flag &= ~P_STOPPED_SIG;
191 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped"));
194 * Note that we are exiting and do another wakeup of anyone in
195 * PIOCWAIT in case they aren't listening for S_EXIT stops or
196 * decided to wait again after we told them we are exiting.
198 p->p_flag |= P_WEXIT;
202 * Wait for any processes that have a hold on our vmspace to
203 * release their reference.
205 while (p->p_lock > 0)
206 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
208 p->p_xstat = rv; /* Let event handler change exit status */
210 /* Drain the limit callout while we don't have the proc locked */
211 callout_drain(&p->p_limco);
215 * The Sun BSM exit token contains two components: an exit status as
216 * passed to exit(), and a return value to indicate what sort of exit
217 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
218 * what the return value is.
220 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0);
221 AUDIT_SYSCALL_EXIT(0, td);
224 /* Are we a task leader? */
225 if (p == p->p_leader) {
226 mtx_lock(&ppeers_lock);
234 while (p->p_peers != NULL)
235 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
236 mtx_unlock(&ppeers_lock);
240 * Check if any loadable modules need anything done at process exit.
241 * E.g. SYSV IPC stuff
242 * XXX what if one of these generates an error?
244 EVENTHANDLER_INVOKE(process_exit, p);
247 * If parent is waiting for us to exit or exec,
248 * P_PPWAIT is set; we will wakeup the parent below.
251 rv = p->p_xstat; /* Event handler could change exit status */
253 p->p_flag &= ~(P_TRACED | P_PPWAIT);
256 * Stop the real interval timer. If the handler is currently
257 * executing, prevent it from rearming itself and let it finish.
259 if (timevalisset(&p->p_realtimer.it_value) &&
260 callout_stop(&p->p_itcallout) == 0) {
261 timevalclear(&p->p_realtimer.it_interval);
262 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
263 KASSERT(!timevalisset(&p->p_realtimer.it_value),
264 ("realtime timer is still armed"));
269 * Reset any sigio structures pointing to us as a result of
270 * F_SETOWN with our pid.
272 funsetownlst(&p->p_sigiolst);
275 * If this process has an nlminfo data area (for lockd), release it
277 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
278 (*nlminfo_release_p)(p);
281 * Close open files and release open-file table.
287 * If this thread tickled GEOM, we need to wait for the giggling to
288 * stop before we return to userland
290 if (td->td_pflags & TDP_GEOM)
294 * Remove ourself from our leader's peer list and wake our leader.
296 mtx_lock(&ppeers_lock);
297 if (p->p_leader->p_peers) {
299 while (q->p_peers != p)
301 q->p_peers = p->p_peers;
304 mtx_unlock(&ppeers_lock);
308 sx_xlock(&proctree_lock);
309 if (SESS_LEADER(p)) {
310 struct session *sp = p->p_session;
314 * s_ttyp is not zero'd; we use this to indicate that
315 * the session once had a controlling terminal. (for
316 * logging and informational purposes)
326 * Signal foreground pgrp and revoke access to
327 * controlling terminal if it has not been revoked
330 * Because the TTY may have been revoked in the mean
331 * time and could already have a new session associated
332 * with it, make sure we don't send a SIGHUP to a
333 * foreground process group that does not belong to this
339 if (tp->t_session == sp)
340 tty_signal_pgrp(tp, SIGHUP);
345 sx_xunlock(&proctree_lock);
346 if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) {
347 VOP_REVOKE(ttyvp, REVOKEALL);
348 VOP_UNLOCK(ttyvp, 0);
350 sx_xlock(&proctree_lock);
353 fixjobc(p, p->p_pgrp, 0);
354 sx_xunlock(&proctree_lock);
355 (void)acct_process(td);
357 /* Release the TTY now we've unlocked everything. */
364 * Release reference to text vnode
366 if ((vtmp = p->p_textvp) != NULL) {
368 locked = VFS_LOCK_GIANT(vtmp->v_mount);
370 VFS_UNLOCK_GIANT(locked);
374 * Release our limits structure.
383 * Remove proc from allproc queue and pidhash chain.
384 * Place onto zombproc. Unlink from parent's child list.
386 sx_xlock(&allproc_lock);
387 LIST_REMOVE(p, p_list);
388 LIST_INSERT_HEAD(&zombproc, p, p_list);
389 LIST_REMOVE(p, p_hash);
390 sx_xunlock(&allproc_lock);
393 * Call machine-dependent code to release any
394 * machine-dependent resources other than the address space.
395 * The address space is released by "vmspace_exitfree(p)" in
400 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
403 * Reparent all of our children to init.
405 sx_xlock(&proctree_lock);
406 q = LIST_FIRST(&p->p_children);
407 if (q != NULL) /* only need this if any child is S_ZOMB */
409 for (; q != NULL; q = nq) {
410 nq = LIST_NEXT(q, p_sibling);
412 proc_reparent(q, initproc);
413 q->p_sigparent = SIGCHLD;
415 * Traced processes are killed
416 * since their existence means someone is screwing up.
418 if (q->p_flag & P_TRACED) {
421 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
422 FOREACH_THREAD_IN_PROC(q, temp)
423 temp->td_dbgflags &= ~TDB_SUSPEND;
429 /* Save exit status. */
433 /* Tell the prison that we are gone. */
434 prison_proc_free(p->p_ucred->cr_prison);
438 * Tell the DTrace fasttrap provider about the exit if it
439 * has declared an interest.
441 if (dtrace_fasttrap_exit)
442 dtrace_fasttrap_exit(p);
446 * Notify interested parties of our demise.
448 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
451 int reason = CLD_EXITED;
454 else if (WIFSIGNALED(rv))
456 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0);
460 * Just delete all entries in the p_klist. At this point we won't
461 * report any more events, and there are nasty race conditions that
462 * can beat us if we don't.
464 knlist_clear(&p->p_klist, 1);
467 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
468 * flag set, or if the handler is set to SIG_IGN, notify process
469 * 1 instead (and hope it will handle this situation).
471 PROC_LOCK(p->p_pptr);
472 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
473 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
476 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
479 proc_reparent(p, initproc);
480 p->p_sigparent = SIGCHLD;
481 PROC_LOCK(p->p_pptr);
484 * Notify parent, so in case he was wait(2)ing or
485 * executing waitpid(2) with our pid, he will
490 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
492 if (p->p_pptr == initproc)
493 psignal(p->p_pptr, SIGCHLD);
494 else if (p->p_sigparent != 0) {
495 if (p->p_sigparent == SIGCHLD)
497 else /* LINUX thread */
498 psignal(p->p_pptr, p->p_sigparent);
500 sx_xunlock(&proctree_lock);
503 * The state PRS_ZOMBIE prevents other proesses from sending
504 * signal to the process, to avoid memory leak, we free memory
505 * for signal queue at the time when the state is set.
507 sigqueue_flush(&p->p_sigqueue);
508 sigqueue_flush(&td->td_sigqueue);
511 * We have to wait until after acquiring all locks before
512 * changing p_state. We need to avoid all possible context
513 * switches (including ones from blocking on a mutex) while
514 * marked as a zombie. We also have to set the zombie state
515 * before we release the parent process' proc lock to avoid
516 * a lost wakeup. So, we first call wakeup, then we grab the
517 * sched lock, update the state, and release the parent process'
521 cv_broadcast(&p->p_pwait);
522 sched_exit(p->p_pptr, td);
524 p->p_state = PRS_ZOMBIE;
525 PROC_UNLOCK(p->p_pptr);
528 * Hopefully no one will try to deliver a signal to the process this
531 knlist_destroy(&p->p_klist);
534 * Save our children's rusage information in our exit rusage.
536 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
539 * Make sure the scheduler takes this thread out of its tables etc.
540 * This will also release this thread's reference to the ucred.
541 * Other thread parts to release include pcb bits and such.
547 #ifndef _SYS_SYSPROTO_H_
556 abort2(struct thread *td, struct abort2_args *uap)
558 struct proc *p = td->td_proc;
564 * Do it right now so we can log either proper call of abort2(), or
565 * note, that invalid argument was passed. 512 is big enough to
566 * handle 16 arguments' descriptions with additional comments.
568 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
570 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
571 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
573 * Since we can't return from abort2(), send SIGKILL in cases, where
574 * abort2() was called improperly
577 /* Prevent from DoSes from user-space. */
578 if (uap->nargs < 0 || uap->nargs > 16)
580 if (uap->nargs > 0) {
581 if (uap->args == NULL)
583 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
588 * Limit size of 'reason' string to 128. Will fit even when
589 * maximal number of arguments was chosen to be logged.
591 if (uap->why != NULL) {
592 error = sbuf_copyin(sb, uap->why, 128);
596 sbuf_printf(sb, "(null)");
598 if (uap->nargs > 0) {
599 sbuf_printf(sb, "(");
600 for (i = 0;i < uap->nargs; i++)
601 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
602 sbuf_printf(sb, ")");
605 * Final stage: arguments were proper, string has been
606 * successfully copied from userspace, and copying pointers
607 * from user-space succeed.
611 if (sig == SIGKILL) {
613 sbuf_printf(sb, " (Reason text inaccessible)");
617 log(LOG_INFO, "%s", sbuf_data(sb));
619 exit1(td, W_EXITCODE(0, sig));
626 * The dirty work is handled by kern_wait().
629 owait(struct thread *td, struct owait_args *uap __unused)
633 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
635 td->td_retval[1] = status;
638 #endif /* COMPAT_43 */
641 * The dirty work is handled by kern_wait().
644 wait4(struct thread *td, struct wait_args *uap)
646 struct rusage ru, *rup;
649 if (uap->rusage != NULL)
653 error = kern_wait(td, uap->pid, &status, uap->options, rup);
654 if (uap->status != NULL && error == 0)
655 error = copyout(&status, uap->status, sizeof(status));
656 if (uap->rusage != NULL && error == 0)
657 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
662 * Reap the remains of a zombie process and optionally return status and
663 * rusage. Asserts and will release both the proctree_lock and the process
664 * lock as part of its work.
667 proc_reap(struct thread *td, struct proc *p, int *status, int options,
668 struct rusage *rusage)
672 sx_assert(&proctree_lock, SA_XLOCKED);
673 PROC_LOCK_ASSERT(p, MA_OWNED);
674 PROC_SLOCK_ASSERT(p, MA_OWNED);
675 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
680 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
683 td->td_retval[0] = p->p_pid;
685 *status = p->p_xstat; /* convert to int */
686 if (options & WNOWAIT) {
688 * Only poll, returning the status. Caller does not wish to
689 * release the proc struct just yet.
692 sx_xunlock(&proctree_lock);
697 sigqueue_take(p->p_ksi);
702 * If we got the child via a ptrace 'attach', we need to give it back
705 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
710 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
712 cv_broadcast(&p->p_pwait);
714 sx_xunlock(&proctree_lock);
719 * Remove other references to this process to ensure we have an
720 * exclusive reference.
722 sx_xlock(&allproc_lock);
723 LIST_REMOVE(p, p_list); /* off zombproc */
724 sx_xunlock(&allproc_lock);
725 LIST_REMOVE(p, p_sibling);
727 sx_xunlock(&proctree_lock);
730 * As a side effect of this lock, we know that all other writes to
731 * this proc are visible now, so no more locking is needed for p.
734 p->p_xstat = 0; /* XXX: why? */
737 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
741 * Decrement the count of procs running with this uid.
743 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
746 * Free credentials, arguments, and sigacts.
750 pargs_drop(p->p_args);
752 sigacts_free(p->p_sigacts);
756 * Do any thread-system specific cleanups.
761 * Give vm and machine-dependent layer a chance to free anything that
762 * cpu_exit couldn't release while still running in process context.
768 KASSERT(FIRST_THREAD_IN_PROC(p),
769 ("proc_reap: no residual thread!"));
770 uma_zfree(proc_zone, p);
771 sx_xlock(&allproc_lock);
773 sx_xunlock(&allproc_lock);
777 kern_wait(struct thread *td, pid_t pid, int *status, int options,
778 struct rusage *rusage)
784 AUDIT_ARG_VALUE(options);
792 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE))
795 if (q->p_flag & P_STATCHILD) {
797 q->p_flag &= ~P_STATCHILD;
801 sx_xlock(&proctree_lock);
802 LIST_FOREACH(p, &q->p_children, p_sibling) {
804 if (pid != WAIT_ANY &&
805 p->p_pid != pid && p->p_pgid != -pid) {
809 if (p_canwait(td, p)) {
815 * This special case handles a kthread spawned by linux_clone
816 * (see linux_misc.c). The linux_wait4 and linux_waitpid
817 * functions need to be able to distinguish between waiting
818 * on a process and waiting on a thread. It is a thread if
819 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
820 * signifies we want to wait for threads and not processes.
822 if ((p->p_sigparent != SIGCHLD) ^
823 ((options & WLINUXCLONE) != 0)) {
830 if (p->p_state == PRS_ZOMBIE) {
831 proc_reap(td, p, status, options, rusage);
834 if ((p->p_flag & P_STOPPED_SIG) &&
835 (p->p_suspcount == p->p_numthreads) &&
836 (p->p_flag & P_WAITED) == 0 &&
837 (p->p_flag & P_TRACED || options & WUNTRACED)) {
839 p->p_flag |= P_WAITED;
840 sx_xunlock(&proctree_lock);
841 td->td_retval[0] = p->p_pid;
843 *status = W_STOPCODE(p->p_xstat);
846 sigqueue_take(p->p_ksi);
853 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
854 sx_xunlock(&proctree_lock);
855 td->td_retval[0] = p->p_pid;
856 p->p_flag &= ~P_CONTINUED;
859 sigqueue_take(p->p_ksi);
870 sx_xunlock(&proctree_lock);
873 if (options & WNOHANG) {
874 sx_xunlock(&proctree_lock);
875 td->td_retval[0] = 0;
879 sx_xunlock(&proctree_lock);
880 if (q->p_flag & P_STATCHILD) {
881 q->p_flag &= ~P_STATCHILD;
884 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
892 * Make process 'parent' the new parent of process 'child'.
893 * Must be called with an exclusive hold of proctree lock.
896 proc_reparent(struct proc *child, struct proc *parent)
899 sx_assert(&proctree_lock, SX_XLOCKED);
900 PROC_LOCK_ASSERT(child, MA_OWNED);
901 if (child->p_pptr == parent)
904 PROC_LOCK(child->p_pptr);
905 sigqueue_take(child->p_ksi);
906 PROC_UNLOCK(child->p_pptr);
907 LIST_REMOVE(child, p_sibling);
908 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
909 child->p_pptr = parent;