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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"
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/sysproto.h>
48 #include <sys/eventhandler.h>
49 #include <sys/kernel.h>
50 #include <sys/malloc.h>
52 #include <sys/mutex.h>
54 #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 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 while (p->p_flag & P_HADTHREADS) {
146 * First check if some other thread got here before us..
147 * if so, act apropriatly, (exit or suspend);
149 thread_suspend_check(0);
152 * Kill off the other threads. This requires
153 * some co-operation from other parts of the kernel
154 * so it may not be instantaneous. With this state set
155 * any thread entering the kernel from userspace will
156 * thread_exit() in trap(). Any thread attempting to
157 * sleep will return immediately with EINTR or EWOULDBLOCK
158 * which will hopefully force them to back out to userland
159 * freeing resources as they go. Any thread attempting
160 * to return to userland will thread_exit() from userret().
161 * thread_exit() will unsuspend us when the last of the
162 * other threads exits.
163 * If there is already a thread singler after resumption,
164 * calling thread_single will fail; in that case, we just
165 * re-check all suspension request, the thread should
166 * either be suspended there or exit.
168 if (! thread_single(SINGLE_EXIT))
172 * All other activity in this process is now stopped.
173 * Threading support has been turned off.
176 KASSERT(p->p_numthreads == 1,
177 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
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);
203 /* Drain the limit callout while we don't have the proc locked */
204 callout_drain(&p->p_limco);
208 * The Sun BSM exit token contains two components: an exit status as
209 * passed to exit(), and a return value to indicate what sort of exit
210 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
211 * what the return value is.
213 AUDIT_ARG(exit, WEXITSTATUS(rv), 0);
214 AUDIT_SYSCALL_EXIT(0, td);
217 /* Are we a task leader? */
218 if (p == p->p_leader) {
219 mtx_lock(&ppeers_lock);
227 while (p->p_peers != NULL)
228 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
229 mtx_unlock(&ppeers_lock);
233 * Check if any loadable modules need anything done at process exit.
234 * E.g. SYSV IPC stuff
235 * XXX what if one of these generates an error?
237 EVENTHANDLER_INVOKE(process_exit, p);
240 * If parent is waiting for us to exit or exec,
241 * P_PPWAIT is set; we will wakeup the parent below.
245 p->p_flag &= ~(P_TRACED | P_PPWAIT);
248 * Stop the real interval timer. If the handler is currently
249 * executing, prevent it from rearming itself and let it finish.
251 if (timevalisset(&p->p_realtimer.it_value) &&
252 callout_stop(&p->p_itcallout) == 0) {
253 timevalclear(&p->p_realtimer.it_interval);
254 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
255 KASSERT(!timevalisset(&p->p_realtimer.it_value),
256 ("realtime timer is still armed"));
261 * Reset any sigio structures pointing to us as a result of
262 * F_SETOWN with our pid.
264 funsetownlst(&p->p_sigiolst);
267 * If this process has an nlminfo data area (for lockd), release it
269 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
270 (*nlminfo_release_p)(p);
273 * Close open files and release open-file table.
279 * If this thread tickled GEOM, we need to wait for the giggling to
280 * stop before we return to userland
282 if (td->td_pflags & TDP_GEOM)
286 * Remove ourself from our leader's peer list and wake our leader.
288 mtx_lock(&ppeers_lock);
289 if (p->p_leader->p_peers) {
291 while (q->p_peers != p)
293 q->p_peers = p->p_peers;
296 mtx_unlock(&ppeers_lock);
300 sx_xlock(&proctree_lock);
301 if (SESS_LEADER(p)) {
313 * Controlling process.
314 * Signal foreground pgrp and revoke access to
315 * controlling terminal.
317 * There is no need to drain the terminal here,
318 * because this will be done on revocation.
320 if (sp->s_ttyp != NULL) {
321 struct tty *tp = sp->s_ttyp;
324 tty_signal_pgrp(tp, SIGHUP);
328 * The tty could have been revoked
331 if (ttyvp->v_type != VBAD) {
332 sx_xunlock(&proctree_lock);
333 VOP_LOCK(ttyvp, LK_EXCLUSIVE);
334 VOP_REVOKE(ttyvp, REVOKEALL);
335 VOP_UNLOCK(ttyvp, 0);
336 sx_xlock(&proctree_lock);
340 * s_ttyp is not zero'd; we use this to indicate that
341 * the session once had a controlling terminal.
342 * (for logging and informational purposes)
345 SESS_LOCK(p->p_session);
347 SESS_UNLOCK(p->p_session);
349 fixjobc(p, p->p_pgrp, 0);
350 sx_xunlock(&proctree_lock);
351 (void)acct_process(td);
353 /* Release the TTY now we've unlocked everything. */
358 * Disable tracing, then drain any pending records and release
361 if (p->p_traceflag != 0) {
363 mtx_lock(&ktrace_mtx);
365 mtx_unlock(&ktrace_mtx);
369 mtx_lock(&ktrace_mtx);
370 tracevp = p->p_tracevp;
372 tracecred = p->p_tracecred;
373 p->p_tracecred = NULL;
374 mtx_unlock(&ktrace_mtx);
376 if (tracevp != NULL) {
377 locked = VFS_LOCK_GIANT(tracevp->v_mount);
379 VFS_UNLOCK_GIANT(locked);
381 if (tracecred != NULL)
386 * Release reference to text vnode
388 if ((vtmp = p->p_textvp) != NULL) {
390 locked = VFS_LOCK_GIANT(vtmp->v_mount);
392 VFS_UNLOCK_GIANT(locked);
396 * Release our limits structure.
405 * Remove proc from allproc queue and pidhash chain.
406 * Place onto zombproc. Unlink from parent's child list.
408 sx_xlock(&allproc_lock);
409 LIST_REMOVE(p, p_list);
410 LIST_INSERT_HEAD(&zombproc, p, p_list);
411 LIST_REMOVE(p, p_hash);
412 sx_xunlock(&allproc_lock);
415 * Call machine-dependent code to release any
416 * machine-dependent resources other than the address space.
417 * The address space is released by "vmspace_exitfree(p)" in
422 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
425 * Reparent all of our children to init.
427 sx_xlock(&proctree_lock);
428 q = LIST_FIRST(&p->p_children);
429 if (q != NULL) /* only need this if any child is S_ZOMB */
431 for (; q != NULL; q = nq) {
432 nq = LIST_NEXT(q, p_sibling);
434 proc_reparent(q, initproc);
435 q->p_sigparent = SIGCHLD;
437 * Traced processes are killed
438 * since their existence means someone is screwing up.
440 if (q->p_flag & P_TRACED) {
441 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
447 /* Save exit status. */
454 * Tell the DTrace fasttrap provider about the exit if it
455 * has declared an interest.
457 if (dtrace_fasttrap_exit)
458 dtrace_fasttrap_exit(p);
462 * Notify interested parties of our demise.
464 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
467 int reason = CLD_EXITED;
470 else if (WIFSIGNALED(rv))
472 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0);
476 * Just delete all entries in the p_klist. At this point we won't
477 * report any more events, and there are nasty race conditions that
478 * can beat us if we don't.
480 knlist_clear(&p->p_klist, 1);
483 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
484 * flag set, or if the handler is set to SIG_IGN, notify process
485 * 1 instead (and hope it will handle this situation).
487 PROC_LOCK(p->p_pptr);
488 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
489 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
492 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
495 proc_reparent(p, initproc);
496 p->p_sigparent = SIGCHLD;
497 PROC_LOCK(p->p_pptr);
499 * If this was the last child of our parent, notify
500 * parent, so in case he was wait(2)ing, he will
503 if (LIST_EMPTY(&pp->p_children))
506 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
508 if (p->p_pptr == initproc)
509 psignal(p->p_pptr, SIGCHLD);
510 else if (p->p_sigparent != 0) {
511 if (p->p_sigparent == SIGCHLD)
513 else /* LINUX thread */
514 psignal(p->p_pptr, p->p_sigparent);
516 sx_xunlock(&proctree_lock);
519 * The state PRS_ZOMBIE prevents other proesses from sending
520 * signal to the process, to avoid memory leak, we free memory
521 * for signal queue at the time when the state is set.
523 sigqueue_flush(&p->p_sigqueue);
524 sigqueue_flush(&td->td_sigqueue);
527 * We have to wait until after acquiring all locks before
528 * changing p_state. We need to avoid all possible context
529 * switches (including ones from blocking on a mutex) while
530 * marked as a zombie. We also have to set the zombie state
531 * before we release the parent process' proc lock to avoid
532 * a lost wakeup. So, we first call wakeup, then we grab the
533 * sched lock, update the state, and release the parent process'
537 sched_exit(p->p_pptr, td);
539 p->p_state = PRS_ZOMBIE;
540 PROC_UNLOCK(p->p_pptr);
543 * Hopefully no one will try to deliver a signal to the process this
546 knlist_destroy(&p->p_klist);
549 * Save our children's rusage information in our exit rusage.
551 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
554 * Make sure the scheduler takes this thread out of its tables etc.
555 * This will also release this thread's reference to the ucred.
556 * Other thread parts to release include pcb bits and such.
562 #ifndef _SYS_SYSPROTO_H_
571 abort2(struct thread *td, struct abort2_args *uap)
573 struct proc *p = td->td_proc;
578 error = 0; /* satisfy compiler */
581 * Do it right now so we can log either proper call of abort2(), or
582 * note, that invalid argument was passed. 512 is big enough to
583 * handle 16 arguments' descriptions with additional comments.
585 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
587 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
588 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
590 * Since we can't return from abort2(), send SIGKILL in cases, where
591 * abort2() was called improperly
594 /* Prevent from DoSes from user-space. */
595 if (uap->nargs < 0 || uap->nargs > 16)
597 if (uap->nargs > 0) {
598 if (uap->args == NULL)
600 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
605 * Limit size of 'reason' string to 128. Will fit even when
606 * maximal number of arguments was chosen to be logged.
608 if (uap->why != NULL) {
609 error = sbuf_copyin(sb, uap->why, 128);
613 sbuf_printf(sb, "(null)");
615 if (uap->nargs > 0) {
616 sbuf_printf(sb, "(");
617 for (i = 0;i < uap->nargs; i++)
618 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
619 sbuf_printf(sb, ")");
622 * Final stage: arguments were proper, string has been
623 * successfully copied from userspace, and copying pointers
624 * from user-space succeed.
628 if (sig == SIGKILL) {
630 sbuf_printf(sb, " (Reason text inaccessible)");
634 log(LOG_INFO, "%s", sbuf_data(sb));
636 exit1(td, W_EXITCODE(0, sig));
643 * The dirty work is handled by kern_wait().
646 owait(struct thread *td, struct owait_args *uap __unused)
650 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
652 td->td_retval[1] = status;
655 #endif /* COMPAT_43 */
658 * The dirty work is handled by kern_wait().
661 wait4(struct thread *td, struct wait_args *uap)
663 struct rusage ru, *rup;
666 if (uap->rusage != NULL)
670 error = kern_wait(td, uap->pid, &status, uap->options, rup);
671 if (uap->status != NULL && error == 0)
672 error = copyout(&status, uap->status, sizeof(status));
673 if (uap->rusage != NULL && error == 0)
674 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
679 kern_wait(struct thread *td, pid_t pid, int *status, int options,
680 struct rusage *rusage)
682 struct proc *p, *q, *t;
693 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
696 if (q->p_flag & P_STATCHILD) {
698 q->p_flag &= ~P_STATCHILD;
702 sx_xlock(&proctree_lock);
703 LIST_FOREACH(p, &q->p_children, p_sibling) {
705 if (pid != WAIT_ANY &&
706 p->p_pid != pid && p->p_pgid != -pid) {
710 if (p_canwait(td, p)) {
716 * This special case handles a kthread spawned by linux_clone
717 * (see linux_misc.c). The linux_wait4 and linux_waitpid
718 * functions need to be able to distinguish between waiting
719 * on a process and waiting on a thread. It is a thread if
720 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
721 * signifies we want to wait for threads and not processes.
723 if ((p->p_sigparent != SIGCHLD) ^
724 ((options & WLINUXCLONE) != 0)) {
731 if (p->p_state == PRS_ZOMBIE) {
734 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
737 td->td_retval[0] = p->p_pid;
739 *status = p->p_xstat; /* convert to int */
741 sigqueue_take(p->p_ksi);
745 * If we got the child via a ptrace 'attach',
746 * we need to give it back to the old parent.
749 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
754 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
757 sx_xunlock(&proctree_lock);
762 * Remove other references to this process to ensure
763 * we have an exclusive reference.
765 sx_xlock(&allproc_lock);
766 LIST_REMOVE(p, p_list); /* off zombproc */
767 sx_xunlock(&allproc_lock);
768 LIST_REMOVE(p, p_sibling);
770 sx_xunlock(&proctree_lock);
773 * As a side effect of this lock, we know that
774 * all other writes to this proc are visible now, so
775 * no more locking is needed for p.
778 p->p_xstat = 0; /* XXX: why? */
781 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru,
786 * Decrement the count of procs running with this uid.
788 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
791 * Free credentials, arguments, and sigacts.
795 pargs_drop(p->p_args);
797 sigacts_free(p->p_sigacts);
801 * Do any thread-system specific cleanups.
806 * Give vm and machine-dependent layer a chance
807 * to free anything that cpu_exit couldn't
808 * release while still running in process context.
814 KASSERT(FIRST_THREAD_IN_PROC(p),
815 ("kern_wait: no residual thread!"));
816 uma_zfree(proc_zone, p);
817 sx_xlock(&allproc_lock);
819 sx_xunlock(&allproc_lock);
822 if ((p->p_flag & P_STOPPED_SIG) &&
823 (p->p_suspcount == p->p_numthreads) &&
824 (p->p_flag & P_WAITED) == 0 &&
825 (p->p_flag & P_TRACED || options & WUNTRACED)) {
827 p->p_flag |= P_WAITED;
828 sx_xunlock(&proctree_lock);
829 td->td_retval[0] = p->p_pid;
831 *status = W_STOPCODE(p->p_xstat);
834 sigqueue_take(p->p_ksi);
841 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
842 sx_xunlock(&proctree_lock);
843 td->td_retval[0] = p->p_pid;
844 p->p_flag &= ~P_CONTINUED;
847 sigqueue_take(p->p_ksi);
858 sx_xunlock(&proctree_lock);
861 if (options & WNOHANG) {
862 sx_xunlock(&proctree_lock);
863 td->td_retval[0] = 0;
867 sx_xunlock(&proctree_lock);
868 if (q->p_flag & P_STATCHILD) {
869 q->p_flag &= ~P_STATCHILD;
872 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
880 * Make process 'parent' the new parent of process 'child'.
881 * Must be called with an exclusive hold of proctree lock.
884 proc_reparent(struct proc *child, struct proc *parent)
887 sx_assert(&proctree_lock, SX_XLOCKED);
888 PROC_LOCK_ASSERT(child, MA_OWNED);
889 if (child->p_pptr == parent)
892 PROC_LOCK(child->p_pptr);
893 sigqueue_take(child->p_ksi);
894 PROC_UNLOCK(child->p_pptr);
895 LIST_REMOVE(child, p_sibling);
896 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
897 child->p_pptr = parent;