2 * Copyright (c) 1982, 1986, 1989, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
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24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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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_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>
56 #include <sys/vmmeter.h>
57 #include <sys/vnode.h>
58 #include <sys/resourcevar.h>
60 #include <sys/signalvar.h>
61 #include <sys/sched.h>
63 #include <sys/syscallsubr.h>
64 #include <sys/syslog.h>
65 #include <sys/ptrace.h>
66 #include <sys/acct.h> /* for acct_process() function prototype */
67 #include <sys/filedesc.h>
72 #include <sys/ktrace.h>
75 #include <security/audit/audit.h>
78 #include <vm/vm_extern.h>
79 #include <vm/vm_param.h>
81 #include <vm/vm_map.h>
82 #include <vm/vm_page.h>
85 /* Required to be non-static for SysVR4 emulator */
86 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
88 /* Hook for NFS teardown procedure. */
89 void (*nlminfo_release_p)(struct proc *p);
98 sys_exit(struct thread *td, struct sys_exit_args *uap)
101 exit1(td, W_EXITCODE(uap->rval, 0));
106 * Exit: deallocate address space and other resources, change proc state
107 * to zombie, and unlink proc from allproc and parent's lists. Save exit
108 * status and rusage for wait(). Check for child processes and orphan them.
111 exit1(struct thread *td, int rv)
113 uint64_t new_switchtime;
114 struct proc *p, *nq, *q;
120 struct vnode *tracevp;
121 struct ucred *tracecred;
127 * Drop Giant if caller has it. Eventually we should warn about
128 * being called with Giant held.
130 while (mtx_owned(&Giant))
135 printf("init died (signal %d, exit %d)\n",
136 WTERMSIG(rv), WEXITSTATUS(rv));
137 panic("Going nowhere without my init!");
141 * MUST abort all other threads before proceeding past here.
144 if (p->p_flag & P_HADTHREADS) {
147 * First check if some other thread got here before us..
148 * if so, act apropriatly, (exit or suspend);
150 thread_suspend_check(0);
153 * Kill off the other threads. This requires
154 * some co-operation from other parts of the kernel
155 * so it may not be instantaneous. With this state set
156 * any thread entering the kernel from userspace will
157 * thread_exit() in trap(). Any thread attempting to
158 * sleep will return immediately with EINTR or EWOULDBLOCK
159 * which will hopefully force them to back out to userland
160 * freeing resources as they go. Any thread attempting
161 * to return to userland will thread_exit() from userret().
162 * thread_exit() will unsuspend us when the last of the
163 * other threads exits.
164 * If there is already a thread singler after resumption,
165 * calling thread_single will fail; in that case, we just
166 * re-check all suspension request, the thread should
167 * either be suspended there or exit.
169 if (thread_single(SINGLE_EXIT))
173 * All other activity in this process is now stopped.
174 * Threading support has been turned off.
179 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
180 * on our vmspace, so we should block below until they have
181 * released their reference to us. Note that if they have
182 * requested S_EXIT stops we will block here until they ack
185 _STOPEVENT(p, S_EXIT, rv);
188 * Note that we are exiting and do another wakeup of anyone in
189 * PIOCWAIT in case they aren't listening for S_EXIT stops or
190 * decided to wait again after we told them we are exiting.
192 p->p_flag |= P_WEXIT;
196 * Wait for any processes that have a hold on our vmspace to
197 * release their reference.
199 while (p->p_lock > 0)
200 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
202 PROC_LOCK(p->p_pptr);
203 sigqueue_take(p->p_ksi);
204 PROC_UNLOCK(p->p_pptr);
210 * The Sun BSM exit token contains two components: an exit status as
211 * passed to exit(), and a return value to indicate what sort of exit
212 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
213 * what the return value is.
215 AUDIT_ARG(exit, WEXITSTATUS(rv), 0);
216 AUDIT_SYSCALL_EXIT(0, td);
219 /* Are we a task leader? */
220 if (p == p->p_leader) {
221 mtx_lock(&ppeers_lock);
229 while (p->p_peers != NULL)
230 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
231 mtx_unlock(&ppeers_lock);
235 * Check if any loadable modules need anything done at process exit.
236 * E.g. SYSV IPC stuff
237 * XXX what if one of these generates an error?
239 EVENTHANDLER_INVOKE(process_exit, p);
241 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
244 * If parent is waiting for us to exit or exec,
245 * P_PPWAIT is set; we will wakeup the parent below.
249 p->p_flag &= ~(P_TRACED | P_PPWAIT);
252 * Stop the real interval timer. If the handler is currently
253 * executing, prevent it from rearming itself and let it finish.
255 if (timevalisset(&p->p_realtimer.it_value) &&
256 callout_stop(&p->p_itcallout) == 0) {
257 timevalclear(&p->p_realtimer.it_interval);
258 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
259 KASSERT(!timevalisset(&p->p_realtimer.it_value),
260 ("realtime timer is still armed"));
262 sigqueue_flush(&p->p_sigqueue);
263 sigqueue_flush(&td->td_sigqueue);
267 * Reset any sigio structures pointing to us as a result of
268 * F_SETOWN with our pid.
270 mtx_lock(&Giant); /* XXX: not sure if needed */
271 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);
306 /* The next two chunks should probably be moved to vmspace_exit. */
309 * Release user portion of address space.
310 * This releases references to vnodes,
311 * which could cause I/O if the file has been unlinked.
312 * Need to do this early enough that we can still sleep.
313 * Can't free the entire vmspace as the kernel stack
314 * may be mapped within that space also.
316 * Processes sharing the same vmspace may exit in one order, and
317 * get cleaned up by vmspace_exit() in a different order. The
318 * last exiting process to reach this point releases as much of
319 * the environment as it can, and the last process cleaned up
320 * by vmspace_exit() (which decrements exitingcnt) cleans up the
323 atomic_add_int(&vm->vm_exitingcnt, 1);
325 refcnt = vm->vm_refcnt;
326 while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1));
329 pmap_remove_pages(vmspace_pmap(vm), vm_map_min(&vm->vm_map),
330 vm_map_max(&vm->vm_map));
331 (void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map),
332 vm_map_max(&vm->vm_map));
335 sx_xlock(&proctree_lock);
336 if (SESS_LEADER(p)) {
341 locked = VFS_LOCK_GIANT(sp->s_ttyvp->v_mount);
343 * Controlling process.
344 * Signal foreground pgrp,
345 * drain controlling terminal
346 * and revoke access to controlling terminal.
348 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
350 if (sp->s_ttyp->t_pgrp) {
351 PGRP_LOCK(sp->s_ttyp->t_pgrp);
352 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
353 PGRP_UNLOCK(sp->s_ttyp->t_pgrp);
355 /* XXX tp should be locked. */
356 sx_xunlock(&proctree_lock);
358 sx_xlock(&proctree_lock);
360 * The tty could have been revoked
365 SESS_LOCK(p->p_session);
367 SESS_UNLOCK(p->p_session);
368 sx_xunlock(&proctree_lock);
369 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td);
370 VOP_REVOKE(ttyvp, REVOKEALL);
372 sx_xlock(&proctree_lock);
377 SESS_LOCK(p->p_session);
379 SESS_UNLOCK(p->p_session);
383 * s_ttyp is not zero'd; we use this to indicate
384 * that the session once had a controlling terminal.
385 * (for logging and informational purposes)
387 VFS_UNLOCK_GIANT(locked);
389 SESS_LOCK(p->p_session);
391 SESS_UNLOCK(p->p_session);
393 fixjobc(p, p->p_pgrp, 0);
394 sx_xunlock(&proctree_lock);
395 (void)acct_process(td);
398 * Drain any pending records on the thread and release the trace
399 * file. It might be better if drain-and-clear were atomic.
403 mtx_lock(&ktrace_mtx);
404 p->p_traceflag = 0; /* don't trace the vrele() */
405 tracevp = p->p_tracevp;
407 tracecred = p->p_tracecred;
408 p->p_tracecred = NULL;
409 mtx_unlock(&ktrace_mtx);
411 if (tracevp != NULL) {
412 locked = VFS_LOCK_GIANT(tracevp->v_mount);
414 VFS_UNLOCK_GIANT(locked);
416 if (tracecred != NULL)
420 * Release reference to text vnode
422 if ((vtmp = p->p_textvp) != NULL) {
424 locked = VFS_LOCK_GIANT(vtmp->v_mount);
426 VFS_UNLOCK_GIANT(locked);
430 * Release our limits structure.
439 * Remove proc from allproc queue and pidhash chain.
440 * Place onto zombproc. Unlink from parent's child list.
442 sx_xlock(&allproc_lock);
443 LIST_REMOVE(p, p_list);
444 LIST_INSERT_HEAD(&zombproc, p, p_list);
445 LIST_REMOVE(p, p_hash);
446 sx_xunlock(&allproc_lock);
449 * Reparent all of our children to init.
451 sx_xlock(&proctree_lock);
452 q = LIST_FIRST(&p->p_children);
453 if (q != NULL) /* only need this if any child is S_ZOMB */
455 for (; q != NULL; q = nq) {
456 nq = LIST_NEXT(q, p_sibling);
458 proc_reparent(q, initproc);
459 q->p_sigparent = SIGCHLD;
461 * Traced processes are killed
462 * since their existence means someone is screwing up.
464 if (q->p_flag & P_TRACED) {
465 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
472 * Save exit status and finalize rusage info except for times,
473 * adding in child rusage info later when our time is locked.
478 p->p_stats->p_ru.ru_nvcsw++;
479 *p->p_ru = p->p_stats->p_ru;
482 * Notify interested parties of our demise.
484 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
487 * Just delete all entries in the p_klist. At this point we won't
488 * report any more events, and there are nasty race conditions that
489 * can beat us if we don't.
491 knlist_clear(&p->p_klist, 1);
494 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
495 * flag set, or if the handler is set to SIG_IGN, notify process
496 * 1 instead (and hope it will handle this situation).
498 PROC_LOCK(p->p_pptr);
499 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
500 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
503 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
506 proc_reparent(p, initproc);
507 p->p_sigparent = SIGCHLD;
508 PROC_LOCK(p->p_pptr);
510 * If this was the last child of our parent, notify
511 * parent, so in case he was wait(2)ing, he will
514 if (LIST_EMPTY(&pp->p_children))
517 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
519 if (p->p_pptr == initproc)
520 psignal(p->p_pptr, SIGCHLD);
521 else if (p->p_sigparent != 0) {
522 if (p->p_sigparent == SIGCHLD)
524 else /* LINUX thread */
525 psignal(p->p_pptr, p->p_sigparent);
527 PROC_UNLOCK(p->p_pptr);
531 * Finally, call machine-dependent code to release the remaining
532 * resources including address space.
533 * The address space is released by "vmspace_exitfree(p)" in
538 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object,
539 "process (pid %d) exiting", p->p_pid);
542 PROC_LOCK(p->p_pptr);
543 sx_xunlock(&proctree_lock);
546 * We have to wait until after acquiring all locks before
547 * changing p_state. We need to avoid all possible context
548 * switches (including ones from blocking on a mutex) while
549 * marked as a zombie. We also have to set the zombie state
550 * before we release the parent process' proc lock to avoid
551 * a lost wakeup. So, we first call wakeup, then we grab the
552 * sched lock, update the state, and release the parent process'
556 mtx_lock_spin(&sched_lock);
557 p->p_state = PRS_ZOMBIE;
558 PROC_UNLOCK(p->p_pptr);
560 /* Do the same timestamp bookkeeping that mi_switch() would do. */
561 new_switchtime = cpu_ticks();
562 p->p_rux.rux_runtime += (new_switchtime - PCPU_GET(switchtime));
563 p->p_rux.rux_uticks += td->td_uticks;
564 p->p_rux.rux_sticks += td->td_sticks;
565 p->p_rux.rux_iticks += td->td_iticks;
566 PCPU_SET(switchtime, new_switchtime);
567 PCPU_SET(switchticks, ticks);
570 /* Add our usage into the usage of all our children. */
571 ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
573 sched_exit(p->p_pptr, td);
576 * Hopefully no one will try to deliver a signal to the process this
579 knlist_destroy(&p->p_klist);
582 * Make sure the scheduler takes this thread out of its tables etc.
583 * This will also release this thread's reference to the ucred.
584 * Other thread parts to release include pcb bits and such.
590 #ifndef _SYS_SYSPROTO_H_
602 abort2(struct thread *td, struct abort2_args *uap)
604 struct proc *p = td->td_proc;
609 error = 0; /* satisfy compiler */
612 * Do it right now so we can log either proper call of abort2(), or
613 * note, that invalid argument was passed. 512 is big enough to
614 * handle 16 arguments' descriptions with additional comments.
616 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
618 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
619 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
621 * Since we can't return from abort2(), send SIGKILL in cases, where
622 * abort2() was called improperly
625 /* Prevent from DoSes from user-space. */
626 if (uap->nargs < 0 || uap->nargs > 16)
628 if (uap->args == NULL)
630 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
634 * Limit size of 'reason' string to 128. Will fit even when
635 * maximal number of arguments was chosen to be logged.
637 if (uap->why != NULL) {
638 error = sbuf_copyin(sb, uap->why, 128);
642 sbuf_printf(sb, "(null)");
645 sbuf_printf(sb, "(");
646 for (i = 0;i < uap->nargs; i++)
647 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
648 sbuf_printf(sb, ")");
651 * Final stage: arguments were proper, string has been
652 * successfully copied from userspace, and copying pointers
653 * from user-space succeed.
657 if (sig == SIGKILL) {
659 sbuf_printf(sb, " (Reason text inaccessible)");
663 log(LOG_INFO, "%s", sbuf_data(sb));
665 exit1(td, W_EXITCODE(0, sig));
672 * The dirty work is handled by kern_wait().
677 owait(struct thread *td, struct owait_args *uap __unused)
681 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
683 td->td_retval[1] = status;
686 #endif /* COMPAT_43 */
689 * The dirty work is handled by kern_wait().
694 wait4(struct thread *td, struct wait_args *uap)
696 struct rusage ru, *rup;
699 if (uap->rusage != NULL)
703 error = kern_wait(td, uap->pid, &status, uap->options, rup);
704 if (uap->status != NULL && error == 0)
705 error = copyout(&status, uap->status, sizeof(status));
706 if (uap->rusage != NULL && error == 0)
707 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
712 kern_wait(struct thread *td, pid_t pid, int *status, int options,
713 struct rusage *rusage)
715 struct proc *p, *q, *t;
726 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
729 if (q->p_flag & P_STATCHILD) {
731 q->p_flag &= ~P_STATCHILD;
735 sx_xlock(&proctree_lock);
736 LIST_FOREACH(p, &q->p_children, p_sibling) {
738 if (pid != WAIT_ANY &&
739 p->p_pid != pid && p->p_pgid != -pid) {
743 if (p_canwait(td, p)) {
749 * This special case handles a kthread spawned by linux_clone
750 * (see linux_misc.c). The linux_wait4 and linux_waitpid
751 * functions need to be able to distinguish between waiting
752 * on a process and waiting on a thread. It is a thread if
753 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
754 * signifies we want to wait for threads and not processes.
756 if ((p->p_sigparent != SIGCHLD) ^
757 ((options & WLINUXCLONE) != 0)) {
763 if (p->p_state == PRS_ZOMBIE) {
766 * It is possible that the last thread of this
767 * process is still running on another CPU
768 * in thread_exit() after having dropped the process
769 * lock via PROC_UNLOCK() but before it has completed
770 * cpu_throw(). In that case, the other thread must
771 * still hold sched_lock, so simply by acquiring
772 * sched_lock once we will wait long enough for the
773 * thread to exit in that case.
775 mtx_lock_spin(&sched_lock);
776 mtx_unlock_spin(&sched_lock);
778 td->td_retval[0] = p->p_pid;
780 *status = p->p_xstat; /* convert to int */
783 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
787 sigqueue_take(p->p_ksi);
791 * If we got the child via a ptrace 'attach',
792 * we need to give it back to the old parent.
795 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
800 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
803 sx_xunlock(&proctree_lock);
808 * Remove other references to this process to ensure
809 * we have an exclusive reference.
811 sx_xlock(&allproc_lock);
812 LIST_REMOVE(p, p_list); /* off zombproc */
813 sx_xunlock(&allproc_lock);
814 LIST_REMOVE(p, p_sibling);
816 sx_xunlock(&proctree_lock);
819 * As a side effect of this lock, we know that
820 * all other writes to this proc are visible now, so
821 * no more locking is needed for p.
824 p->p_xstat = 0; /* XXX: why? */
827 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru,
830 FREE(p->p_ru, M_ZOMBIE);
834 * Decrement the count of procs running with this uid.
836 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
839 * Free credentials, arguments, and sigacts.
843 pargs_drop(p->p_args);
845 sigacts_free(p->p_sigacts);
849 * Do any thread-system specific cleanups.
854 * Give vm and machine-dependent layer a chance
855 * to free anything that cpu_exit couldn't
856 * release while still running in process context.
865 KASSERT(FIRST_THREAD_IN_PROC(p),
866 ("kern_wait: no residual thread!"));
867 uma_zfree(proc_zone, p);
868 sx_xlock(&allproc_lock);
870 sx_xunlock(&allproc_lock);
873 mtx_lock_spin(&sched_lock);
874 if ((p->p_flag & P_STOPPED_SIG) &&
875 (p->p_suspcount == p->p_numthreads) &&
876 (p->p_flag & P_WAITED) == 0 &&
877 (p->p_flag & P_TRACED || options & WUNTRACED)) {
878 mtx_unlock_spin(&sched_lock);
879 p->p_flag |= P_WAITED;
880 sx_xunlock(&proctree_lock);
881 td->td_retval[0] = p->p_pid;
883 *status = W_STOPCODE(p->p_xstat);
887 sigqueue_take(p->p_ksi);
892 mtx_unlock_spin(&sched_lock);
893 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
894 sx_xunlock(&proctree_lock);
895 td->td_retval[0] = p->p_pid;
896 p->p_flag &= ~P_CONTINUED;
900 sigqueue_take(p->p_ksi);
910 sx_xunlock(&proctree_lock);
913 if (options & WNOHANG) {
914 sx_xunlock(&proctree_lock);
915 td->td_retval[0] = 0;
919 sx_xunlock(&proctree_lock);
920 if (q->p_flag & P_STATCHILD) {
921 q->p_flag &= ~P_STATCHILD;
924 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
932 * Make process 'parent' the new parent of process 'child'.
933 * Must be called with an exclusive hold of proctree lock.
936 proc_reparent(struct proc *child, struct proc *parent)
939 sx_assert(&proctree_lock, SX_XLOCKED);
940 PROC_LOCK_ASSERT(child, MA_OWNED);
941 if (child->p_pptr == parent)
944 LIST_REMOVE(child, p_sibling);
945 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
946 child->p_pptr = parent;