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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>
71 #include <sys/ktrace.h>
74 #include <security/audit/audit.h>
75 #include <security/mac/mac_framework.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);
92 * exit -- death of process.
95 sys_exit(struct thread *td, struct sys_exit_args *uap)
98 exit1(td, W_EXITCODE(uap->rval, 0));
103 * Exit: deallocate address space and other resources, change proc state to
104 * zombie, and unlink proc from allproc and parent's lists. Save exit status
105 * and rusage for wait(). Check for child processes and orphan them.
108 exit1(struct thread *td, int rv)
110 struct proc *p, *nq, *q;
115 struct vnode *tracevp;
116 struct ucred *tracecred;
122 * Drop Giant if caller has it. Eventually we should warn about
123 * being called with Giant held.
125 while (mtx_owned(&Giant))
130 printf("init died (signal %d, exit %d)\n",
131 WTERMSIG(rv), WEXITSTATUS(rv));
132 panic("Going nowhere without my init!");
136 * MUST abort all other threads before proceeding past here.
139 if (p->p_flag & P_HADTHREADS) {
142 * First check if some other thread got here before us..
143 * if so, act apropriatly, (exit or suspend);
145 thread_suspend_check(0);
148 * Kill off the other threads. This requires
149 * some co-operation from other parts of the kernel
150 * so it may not be instantaneous. With this state set
151 * any thread entering the kernel from userspace will
152 * thread_exit() in trap(). Any thread attempting to
153 * sleep will return immediately with EINTR or EWOULDBLOCK
154 * which will hopefully force them to back out to userland
155 * freeing resources as they go. Any thread attempting
156 * to return to userland will thread_exit() from userret().
157 * thread_exit() will unsuspend us when the last of the
158 * other threads exits.
159 * If there is already a thread singler after resumption,
160 * calling thread_single will fail; in that case, we just
161 * re-check all suspension request, the thread should
162 * either be suspended there or exit.
164 if (thread_single(SINGLE_EXIT))
168 * All other activity in this process is now stopped.
169 * Threading support has been turned off.
174 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold
175 * on our vmspace, so we should block below until they have
176 * released their reference to us. Note that if they have
177 * requested S_EXIT stops we will block here until they ack
180 _STOPEVENT(p, S_EXIT, rv);
183 * Note that we are exiting and do another wakeup of anyone in
184 * PIOCWAIT in case they aren't listening for S_EXIT stops or
185 * decided to wait again after we told them we are exiting.
187 p->p_flag |= P_WEXIT;
191 * Wait for any processes that have a hold on our vmspace to
192 * release their reference.
194 while (p->p_lock > 0)
195 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
201 * The Sun BSM exit token contains two components: an exit status as
202 * passed to exit(), and a return value to indicate what sort of exit
203 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
204 * what the return value is.
206 AUDIT_ARG(exit, WEXITSTATUS(rv), 0);
207 AUDIT_SYSCALL_EXIT(0, td);
210 /* Are we a task leader? */
211 if (p == p->p_leader) {
212 mtx_lock(&ppeers_lock);
220 while (p->p_peers != NULL)
221 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
222 mtx_unlock(&ppeers_lock);
226 * Check if any loadable modules need anything done at process exit.
227 * E.g. SYSV IPC stuff
228 * XXX what if one of these generates an error?
230 EVENTHANDLER_INVOKE(process_exit, p);
232 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
235 * If parent is waiting for us to exit or exec,
236 * P_PPWAIT is set; we will wakeup the parent below.
240 p->p_flag &= ~(P_TRACED | P_PPWAIT);
243 * Stop the real interval timer. If the handler is currently
244 * executing, prevent it from rearming itself and let it finish.
246 if (timevalisset(&p->p_realtimer.it_value) &&
247 callout_stop(&p->p_itcallout) == 0) {
248 timevalclear(&p->p_realtimer.it_interval);
249 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
250 KASSERT(!timevalisset(&p->p_realtimer.it_value),
251 ("realtime timer is still armed"));
256 * Reset any sigio structures pointing to us as a result of
257 * F_SETOWN with our pid.
259 funsetownlst(&p->p_sigiolst);
262 * If this process has an nlminfo data area (for lockd), release it
264 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
265 (*nlminfo_release_p)(p);
268 * Close open files and release open-file table.
274 * If this thread tickled GEOM, we need to wait for the giggling to
275 * stop before we return to userland
277 if (td->td_pflags & TDP_GEOM)
281 * Remove ourself from our leader's peer list and wake our leader.
283 mtx_lock(&ppeers_lock);
284 if (p->p_leader->p_peers) {
286 while (q->p_peers != p)
288 q->p_peers = p->p_peers;
291 mtx_unlock(&ppeers_lock);
295 mtx_lock(&Giant); /* XXX TTY */
296 sx_xlock(&proctree_lock);
297 if (SESS_LEADER(p)) {
303 * Controlling process.
304 * Signal foreground pgrp,
305 * drain controlling terminal
306 * and revoke access to controlling terminal.
308 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
310 if (sp->s_ttyp->t_pgrp) {
311 PGRP_LOCK(sp->s_ttyp->t_pgrp);
312 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
313 PGRP_UNLOCK(sp->s_ttyp->t_pgrp);
315 /* XXX tp should be locked. */
316 sx_xunlock(&proctree_lock);
318 sx_xlock(&proctree_lock);
320 * The tty could have been revoked
325 SESS_LOCK(p->p_session);
327 SESS_UNLOCK(p->p_session);
328 sx_xunlock(&proctree_lock);
329 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td);
330 VOP_REVOKE(ttyvp, REVOKEALL);
332 sx_xlock(&proctree_lock);
337 SESS_LOCK(p->p_session);
339 SESS_UNLOCK(p->p_session);
343 * s_ttyp is not zero'd; we use this to indicate
344 * that the session once had a controlling terminal.
345 * (for logging and informational purposes)
348 SESS_LOCK(p->p_session);
350 SESS_UNLOCK(p->p_session);
352 fixjobc(p, p->p_pgrp, 0);
353 sx_xunlock(&proctree_lock);
354 (void)acct_process(td);
358 * Drain any pending records on the thread and release the trace
359 * file. It might be better if drain-and-clear were atomic.
363 mtx_lock(&ktrace_mtx);
364 p->p_traceflag = 0; /* don't trace the vrele() */
365 tracevp = p->p_tracevp;
367 tracecred = p->p_tracecred;
368 p->p_tracecred = NULL;
369 mtx_unlock(&ktrace_mtx);
371 if (tracevp != NULL) {
372 locked = VFS_LOCK_GIANT(tracevp->v_mount);
374 VFS_UNLOCK_GIANT(locked);
376 if (tracecred != NULL)
380 * Release reference to text vnode
382 if ((vtmp = p->p_textvp) != NULL) {
384 locked = VFS_LOCK_GIANT(vtmp->v_mount);
386 VFS_UNLOCK_GIANT(locked);
390 * Release our limits structure.
399 * Remove proc from allproc queue and pidhash chain.
400 * Place onto zombproc. Unlink from parent's child list.
402 sx_xlock(&allproc_lock);
403 LIST_REMOVE(p, p_list);
404 LIST_INSERT_HEAD(&zombproc, p, p_list);
405 LIST_REMOVE(p, p_hash);
406 sx_xunlock(&allproc_lock);
409 * Reparent all of our children to init.
411 sx_xlock(&proctree_lock);
412 q = LIST_FIRST(&p->p_children);
413 if (q != NULL) /* only need this if any child is S_ZOMB */
415 for (; q != NULL; q = nq) {
416 nq = LIST_NEXT(q, p_sibling);
418 proc_reparent(q, initproc);
419 q->p_sigparent = SIGCHLD;
421 * Traced processes are killed
422 * since their existence means someone is screwing up.
424 if (q->p_flag & P_TRACED) {
425 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
432 * Save exit status and finalize rusage info except for times,
433 * adding in child rusage info later when our time is locked.
438 p->p_stats->p_ru.ru_nvcsw++;
439 *p->p_ru = p->p_stats->p_ru;
442 * Notify interested parties of our demise.
444 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
447 * Just delete all entries in the p_klist. At this point we won't
448 * report any more events, and there are nasty race conditions that
449 * can beat us if we don't.
451 knlist_clear(&p->p_klist, 1);
454 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
455 * flag set, or if the handler is set to SIG_IGN, notify process
456 * 1 instead (and hope it will handle this situation).
458 PROC_LOCK(p->p_pptr);
459 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
460 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
463 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
466 proc_reparent(p, initproc);
467 p->p_sigparent = SIGCHLD;
468 PROC_LOCK(p->p_pptr);
470 * If this was the last child of our parent, notify
471 * parent, so in case he was wait(2)ing, he will
474 if (LIST_EMPTY(&pp->p_children))
477 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
479 if (p->p_pptr == initproc)
480 psignal(p->p_pptr, SIGCHLD);
481 else if (p->p_sigparent != 0) {
482 if (p->p_sigparent == SIGCHLD)
484 else /* LINUX thread */
485 psignal(p->p_pptr, p->p_sigparent);
487 PROC_UNLOCK(p->p_pptr);
491 * Finally, call machine-dependent code to release the remaining
492 * resources including address space.
493 * The address space is released by "vmspace_exitfree(p)" in
498 WITNESS_WARN(WARN_PANIC, &proctree_lock.lock_object,
499 "process (pid %d) exiting", p->p_pid);
502 PROC_LOCK(p->p_pptr);
503 sx_xunlock(&proctree_lock);
506 * The state PRS_ZOMBIE prevents other proesses from sending
507 * signal to the process, to avoid memory leak, we free memory
508 * for signal queue at the time when the state is set.
510 sigqueue_flush(&p->p_sigqueue);
511 sigqueue_flush(&td->td_sigqueue);
514 * We have to wait until after acquiring all locks before
515 * changing p_state. We need to avoid all possible context
516 * switches (including ones from blocking on a mutex) while
517 * marked as a zombie. We also have to set the zombie state
518 * before we release the parent process' proc lock to avoid
519 * a lost wakeup. So, we first call wakeup, then we grab the
520 * sched lock, update the state, and release the parent process'
524 mtx_lock_spin(&sched_lock);
525 p->p_state = PRS_ZOMBIE;
526 PROC_UNLOCK(p->p_pptr);
528 sched_exit(p->p_pptr, td);
531 * Hopefully no one will try to deliver a signal to the process this
534 knlist_destroy(&p->p_klist);
537 * Make sure the scheduler takes this thread out of its tables etc.
538 * This will also release this thread's reference to the ucred.
539 * Other thread parts to release include pcb bits and such.
545 #ifndef _SYS_SYSPROTO_H_
554 abort2(struct thread *td, struct abort2_args *uap)
556 struct proc *p = td->td_proc;
561 error = 0; /* satisfy compiler */
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->args == NULL)
582 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
586 * Limit size of 'reason' string to 128. Will fit even when
587 * maximal number of arguments was chosen to be logged.
589 if (uap->why != NULL) {
590 error = sbuf_copyin(sb, uap->why, 128);
594 sbuf_printf(sb, "(null)");
597 sbuf_printf(sb, "(");
598 for (i = 0;i < uap->nargs; i++)
599 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
600 sbuf_printf(sb, ")");
603 * Final stage: arguments were proper, string has been
604 * successfully copied from userspace, and copying pointers
605 * from user-space succeed.
609 if (sig == SIGKILL) {
611 sbuf_printf(sb, " (Reason text inaccessible)");
615 log(LOG_INFO, "%s", sbuf_data(sb));
617 exit1(td, W_EXITCODE(0, sig));
624 * The dirty work is handled by kern_wait().
627 owait(struct thread *td, struct owait_args *uap __unused)
631 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
633 td->td_retval[1] = status;
636 #endif /* COMPAT_43 */
639 * The dirty work is handled by kern_wait().
642 wait4(struct thread *td, struct wait_args *uap)
644 struct rusage ru, *rup;
647 if (uap->rusage != NULL)
651 error = kern_wait(td, uap->pid, &status, uap->options, rup);
652 if (uap->status != NULL && error == 0)
653 error = copyout(&status, uap->status, sizeof(status));
654 if (uap->rusage != NULL && error == 0)
655 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
660 kern_wait(struct thread *td, pid_t pid, int *status, int options,
661 struct rusage *rusage)
663 struct proc *p, *q, *t;
674 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
677 if (q->p_flag & P_STATCHILD) {
679 q->p_flag &= ~P_STATCHILD;
683 sx_xlock(&proctree_lock);
684 LIST_FOREACH(p, &q->p_children, p_sibling) {
686 if (pid != WAIT_ANY &&
687 p->p_pid != pid && p->p_pgid != -pid) {
691 if (p_canwait(td, p)) {
697 * This special case handles a kthread spawned by linux_clone
698 * (see linux_misc.c). The linux_wait4 and linux_waitpid
699 * functions need to be able to distinguish between waiting
700 * on a process and waiting on a thread. It is a thread if
701 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
702 * signifies we want to wait for threads and not processes.
704 if ((p->p_sigparent != SIGCHLD) ^
705 ((options & WLINUXCLONE) != 0)) {
711 if (p->p_state == PRS_ZOMBIE) {
714 * It is possible that the last thread of this
715 * process is still running on another CPU
716 * in thread_exit() after having dropped the process
717 * lock via PROC_UNLOCK() but before it has completed
718 * cpu_throw(). In that case, the other thread must
719 * still hold sched_lock, so simply by acquiring
720 * sched_lock once we will wait long enough for the
721 * thread to exit in that case.
723 mtx_lock_spin(&sched_lock);
724 mtx_unlock_spin(&sched_lock);
726 td->td_retval[0] = p->p_pid;
728 *status = p->p_xstat; /* convert to int */
731 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
735 sigqueue_take(p->p_ksi);
739 * If we got the child via a ptrace 'attach',
740 * we need to give it back to the old parent.
743 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
748 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
751 sx_xunlock(&proctree_lock);
756 * Remove other references to this process to ensure
757 * we have an exclusive reference.
759 sx_xlock(&allproc_lock);
760 LIST_REMOVE(p, p_list); /* off zombproc */
761 sx_xunlock(&allproc_lock);
762 LIST_REMOVE(p, p_sibling);
764 sx_xunlock(&proctree_lock);
767 * As a side effect of this lock, we know that
768 * all other writes to this proc are visible now, so
769 * no more locking is needed for p.
772 p->p_xstat = 0; /* XXX: why? */
775 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru,
778 FREE(p->p_ru, M_ZOMBIE);
782 * Decrement the count of procs running with this uid.
784 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
787 * Free credentials, arguments, and sigacts.
791 pargs_drop(p->p_args);
793 sigacts_free(p->p_sigacts);
797 * Do any thread-system specific cleanups.
802 * Give vm and machine-dependent layer a chance
803 * to free anything that cpu_exit couldn't
804 * release while still running in process context.
813 KASSERT(FIRST_THREAD_IN_PROC(p),
814 ("kern_wait: no residual thread!"));
815 uma_zfree(proc_zone, p);
816 sx_xlock(&allproc_lock);
818 sx_xunlock(&allproc_lock);
821 mtx_lock_spin(&sched_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)) {
826 mtx_unlock_spin(&sched_lock);
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);
840 mtx_unlock_spin(&sched_lock);
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;