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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);
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 struct proc *p, *nq, *q;
118 struct vnode *tracevp;
119 struct ucred *tracecred;
125 * Drop Giant if caller has it. Eventually we should warn about
126 * being called with Giant held.
128 while (mtx_owned(&Giant))
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 if (p->p_flag & P_HADTHREADS) {
145 * First check if some other thread got here before us..
146 * if so, act apropriatly, (exit or suspend);
148 thread_suspend_check(0);
151 * Kill off the other threads. This requires
152 * some co-operation from other parts of the kernel
153 * so it may not be instantaneous. With this state set
154 * any thread entering the kernel from userspace will
155 * thread_exit() in trap(). Any thread attempting to
156 * sleep will return immediately with EINTR or EWOULDBLOCK
157 * which will hopefully force them to back out to userland
158 * freeing resources as they go. Any thread attempting
159 * to return to userland will thread_exit() from userret().
160 * thread_exit() will unsuspend us when the last of the
161 * other threads exits.
162 * If there is already a thread singler after resumption,
163 * calling thread_single will fail; in that case, we just
164 * re-check all suspension request, the thread should
165 * either be suspended there or exit.
167 if (thread_single(SINGLE_EXIT))
171 * All other activity in this process is now stopped.
172 * Threading support has been turned off.
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 * Note that we are exiting and do another wakeup of anyone in
187 * PIOCWAIT in case they aren't listening for S_EXIT stops or
188 * decided to wait again after we told them we are exiting.
190 p->p_flag |= P_WEXIT;
194 * Wait for any processes that have a hold on our vmspace to
195 * release their reference.
197 while (p->p_lock > 0)
198 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
204 * The Sun BSM exit token contains two components: an exit status as
205 * passed to exit(), and a return value to indicate what sort of exit
206 * it was. The exit status is WEXITSTATUS(rv), but it's not clear
207 * what the return value is.
209 AUDIT_ARG(exit, WEXITSTATUS(rv), 0);
210 AUDIT_SYSCALL_EXIT(0, td);
213 /* Are we a task leader? */
214 if (p == p->p_leader) {
215 mtx_lock(&ppeers_lock);
223 while (p->p_peers != NULL)
224 msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
225 mtx_unlock(&ppeers_lock);
229 * Check if any loadable modules need anything done at process exit.
230 * E.g. SYSV IPC stuff
231 * XXX what if one of these generates an error?
233 EVENTHANDLER_INVOKE(process_exit, p);
235 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
238 * If parent is waiting for us to exit or exec,
239 * P_PPWAIT is set; we will wakeup the parent below.
243 p->p_flag &= ~(P_TRACED | P_PPWAIT);
246 * Stop the real interval timer. If the handler is currently
247 * executing, prevent it from rearming itself and let it finish.
249 if (timevalisset(&p->p_realtimer.it_value) &&
250 callout_stop(&p->p_itcallout) == 0) {
251 timevalclear(&p->p_realtimer.it_interval);
252 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
253 KASSERT(!timevalisset(&p->p_realtimer.it_value),
254 ("realtime timer is still armed"));
259 * Reset any sigio structures pointing to us as a result of
260 * F_SETOWN with our pid.
262 funsetownlst(&p->p_sigiolst);
265 * If this process has an nlminfo data area (for lockd), release it
267 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
268 (*nlminfo_release_p)(p);
271 * Close open files and release open-file table.
277 * If this thread tickled GEOM, we need to wait for the giggling to
278 * stop before we return to userland
280 if (td->td_pflags & TDP_GEOM)
284 * Remove ourself from our leader's peer list and wake our leader.
286 mtx_lock(&ppeers_lock);
287 if (p->p_leader->p_peers) {
289 while (q->p_peers != p)
291 q->p_peers = p->p_peers;
294 mtx_unlock(&ppeers_lock);
298 mtx_lock(&Giant); /* XXX TTY */
299 sx_xlock(&proctree_lock);
300 if (SESS_LEADER(p)) {
306 * Controlling process.
307 * Signal foreground pgrp,
308 * drain controlling terminal
309 * and revoke access to controlling terminal.
311 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
313 if (sp->s_ttyp->t_pgrp) {
314 PGRP_LOCK(sp->s_ttyp->t_pgrp);
315 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
316 PGRP_UNLOCK(sp->s_ttyp->t_pgrp);
318 /* XXX tp should be locked. */
319 sx_xunlock(&proctree_lock);
321 sx_xlock(&proctree_lock);
323 * The tty could have been revoked
328 SESS_LOCK(p->p_session);
330 SESS_UNLOCK(p->p_session);
331 sx_xunlock(&proctree_lock);
332 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td);
333 VOP_REVOKE(ttyvp, REVOKEALL);
335 sx_xlock(&proctree_lock);
340 SESS_LOCK(p->p_session);
342 SESS_UNLOCK(p->p_session);
346 * s_ttyp is not zero'd; we use this to indicate
347 * that the session once had a controlling terminal.
348 * (for logging and informational purposes)
351 SESS_LOCK(p->p_session);
353 SESS_UNLOCK(p->p_session);
355 fixjobc(p, p->p_pgrp, 0);
356 sx_xunlock(&proctree_lock);
357 (void)acct_process(td);
361 * Drain any pending records on the thread and release the trace
362 * file. It might be better if drain-and-clear were atomic.
366 mtx_lock(&ktrace_mtx);
367 p->p_traceflag = 0; /* don't trace the vrele() */
368 tracevp = p->p_tracevp;
370 tracecred = p->p_tracecred;
371 p->p_tracecred = NULL;
372 mtx_unlock(&ktrace_mtx);
374 if (tracevp != NULL) {
375 locked = VFS_LOCK_GIANT(tracevp->v_mount);
377 VFS_UNLOCK_GIANT(locked);
379 if (tracecred != NULL)
383 * Release reference to text vnode
385 if ((vtmp = p->p_textvp) != NULL) {
387 locked = VFS_LOCK_GIANT(vtmp->v_mount);
389 VFS_UNLOCK_GIANT(locked);
393 * Release our limits structure.
402 * Remove proc from allproc queue and pidhash chain.
403 * Place onto zombproc. Unlink from parent's child list.
405 sx_xlock(&allproc_lock);
406 LIST_REMOVE(p, p_list);
407 LIST_INSERT_HEAD(&zombproc, p, p_list);
408 LIST_REMOVE(p, p_hash);
409 sx_xunlock(&allproc_lock);
412 * Reparent all of our children to init.
414 sx_xlock(&proctree_lock);
415 q = LIST_FIRST(&p->p_children);
416 if (q != NULL) /* only need this if any child is S_ZOMB */
418 for (; q != NULL; q = nq) {
419 nq = LIST_NEXT(q, p_sibling);
421 proc_reparent(q, initproc);
422 q->p_sigparent = SIGCHLD;
424 * Traced processes are killed
425 * since their existence means someone is screwing up.
427 if (q->p_flag & P_TRACED) {
428 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
435 * Save exit status and finalize rusage info except for times,
436 * adding in child rusage info later when our time is locked.
441 p->p_stats->p_ru.ru_nvcsw++;
442 *p->p_ru = p->p_stats->p_ru;
445 * Notify interested parties of our demise.
447 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
450 * Just delete all entries in the p_klist. At this point we won't
451 * report any more events, and there are nasty race conditions that
452 * can beat us if we don't.
454 knlist_clear(&p->p_klist, 1);
457 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
458 * flag set, or if the handler is set to SIG_IGN, notify process
459 * 1 instead (and hope it will handle this situation).
461 PROC_LOCK(p->p_pptr);
462 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
463 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
466 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
469 proc_reparent(p, initproc);
470 p->p_sigparent = SIGCHLD;
471 PROC_LOCK(p->p_pptr);
473 * If this was the last child of our parent, notify
474 * parent, so in case he was wait(2)ing, he will
477 if (LIST_EMPTY(&pp->p_children))
480 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
482 if (p->p_pptr == initproc)
483 psignal(p->p_pptr, SIGCHLD);
484 else if (p->p_sigparent != 0) {
485 if (p->p_sigparent == SIGCHLD)
487 else /* LINUX thread */
488 psignal(p->p_pptr, p->p_sigparent);
490 PROC_UNLOCK(p->p_pptr);
494 * Finally, call machine-dependent code to release the remaining
495 * resources including address space.
496 * The address space is released by "vmspace_exitfree(p)" in
501 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object,
502 "process (pid %d) exiting", p->p_pid);
505 PROC_LOCK(p->p_pptr);
506 sx_xunlock(&proctree_lock);
509 * The state PRS_ZOMBIE prevents other proesses from sending
510 * signal to the process, to avoid memory leak, we free memory
511 * for signal queue at the time when the state is set.
513 sigqueue_flush(&p->p_sigqueue);
514 sigqueue_flush(&td->td_sigqueue);
517 * We have to wait until after acquiring all locks before
518 * changing p_state. We need to avoid all possible context
519 * switches (including ones from blocking on a mutex) while
520 * marked as a zombie. We also have to set the zombie state
521 * before we release the parent process' proc lock to avoid
522 * a lost wakeup. So, we first call wakeup, then we grab the
523 * sched lock, update the state, and release the parent process'
527 mtx_lock_spin(&sched_lock);
528 p->p_state = PRS_ZOMBIE;
529 PROC_UNLOCK(p->p_pptr);
531 sched_exit(p->p_pptr, td);
534 * Hopefully no one will try to deliver a signal to the process this
537 knlist_destroy(&p->p_klist);
540 * Make sure the scheduler takes this thread out of its tables etc.
541 * This will also release this thread's reference to the ucred.
542 * Other thread parts to release include pcb bits and such.
548 #ifndef _SYS_SYSPROTO_H_
560 abort2(struct thread *td, struct abort2_args *uap)
562 struct proc *p = td->td_proc;
567 error = 0; /* satisfy compiler */
570 * Do it right now so we can log either proper call of abort2(), or
571 * note, that invalid argument was passed. 512 is big enough to
572 * handle 16 arguments' descriptions with additional comments.
574 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN);
576 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
577 p->p_comm, p->p_pid, td->td_ucred->cr_uid);
579 * Since we can't return from abort2(), send SIGKILL in cases, where
580 * abort2() was called improperly
583 /* Prevent from DoSes from user-space. */
584 if (uap->nargs < 0 || uap->nargs > 16)
586 if (uap->args == NULL)
588 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *));
592 * Limit size of 'reason' string to 128. Will fit even when
593 * maximal number of arguments was chosen to be logged.
595 if (uap->why != NULL) {
596 error = sbuf_copyin(sb, uap->why, 128);
600 sbuf_printf(sb, "(null)");
603 sbuf_printf(sb, "(");
604 for (i = 0;i < uap->nargs; i++)
605 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]);
606 sbuf_printf(sb, ")");
609 * Final stage: arguments were proper, string has been
610 * successfully copied from userspace, and copying pointers
611 * from user-space succeed.
615 if (sig == SIGKILL) {
617 sbuf_printf(sb, " (Reason text inaccessible)");
621 log(LOG_INFO, "%s", sbuf_data(sb));
623 exit1(td, W_EXITCODE(0, sig));
630 * The dirty work is handled by kern_wait().
635 owait(struct thread *td, struct owait_args *uap __unused)
639 error = kern_wait(td, WAIT_ANY, &status, 0, NULL);
641 td->td_retval[1] = status;
644 #endif /* COMPAT_43 */
647 * The dirty work is handled by kern_wait().
652 wait4(struct thread *td, struct wait_args *uap)
654 struct rusage ru, *rup;
657 if (uap->rusage != NULL)
661 error = kern_wait(td, uap->pid, &status, uap->options, rup);
662 if (uap->status != NULL && error == 0)
663 error = copyout(&status, uap->status, sizeof(status));
664 if (uap->rusage != NULL && error == 0)
665 error = copyout(&ru, uap->rusage, sizeof(struct rusage));
670 kern_wait(struct thread *td, pid_t pid, int *status, int options,
671 struct rusage *rusage)
673 struct proc *p, *q, *t;
684 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
687 if (q->p_flag & P_STATCHILD) {
689 q->p_flag &= ~P_STATCHILD;
693 sx_xlock(&proctree_lock);
694 LIST_FOREACH(p, &q->p_children, p_sibling) {
696 if (pid != WAIT_ANY &&
697 p->p_pid != pid && p->p_pgid != -pid) {
701 if (p_canwait(td, p)) {
707 * This special case handles a kthread spawned by linux_clone
708 * (see linux_misc.c). The linux_wait4 and linux_waitpid
709 * functions need to be able to distinguish between waiting
710 * on a process and waiting on a thread. It is a thread if
711 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
712 * signifies we want to wait for threads and not processes.
714 if ((p->p_sigparent != SIGCHLD) ^
715 ((options & WLINUXCLONE) != 0)) {
721 if (p->p_state == PRS_ZOMBIE) {
724 * It is possible that the last thread of this
725 * process is still running on another CPU
726 * in thread_exit() after having dropped the process
727 * lock via PROC_UNLOCK() but before it has completed
728 * cpu_throw(). In that case, the other thread must
729 * still hold sched_lock, so simply by acquiring
730 * sched_lock once we will wait long enough for the
731 * thread to exit in that case.
733 mtx_lock_spin(&sched_lock);
734 mtx_unlock_spin(&sched_lock);
736 td->td_retval[0] = p->p_pid;
738 *status = p->p_xstat; /* convert to int */
741 calcru(p, &rusage->ru_utime, &rusage->ru_stime);
745 sigqueue_take(p->p_ksi);
749 * If we got the child via a ptrace 'attach',
750 * we need to give it back to the old parent.
753 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
758 tdsignal(t, NULL, SIGCHLD, p->p_ksi);
761 sx_xunlock(&proctree_lock);
766 * Remove other references to this process to ensure
767 * we have an exclusive reference.
769 sx_xlock(&allproc_lock);
770 LIST_REMOVE(p, p_list); /* off zombproc */
771 sx_xunlock(&allproc_lock);
772 LIST_REMOVE(p, p_sibling);
774 sx_xunlock(&proctree_lock);
777 * As a side effect of this lock, we know that
778 * all other writes to this proc are visible now, so
779 * no more locking is needed for p.
782 p->p_xstat = 0; /* XXX: why? */
785 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru,
788 FREE(p->p_ru, M_ZOMBIE);
792 * Decrement the count of procs running with this uid.
794 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
797 * Free credentials, arguments, and sigacts.
801 pargs_drop(p->p_args);
803 sigacts_free(p->p_sigacts);
807 * Do any thread-system specific cleanups.
812 * Give vm and machine-dependent layer a chance
813 * to free anything that cpu_exit couldn't
814 * release while still running in process context.
823 KASSERT(FIRST_THREAD_IN_PROC(p),
824 ("kern_wait: no residual thread!"));
825 uma_zfree(proc_zone, p);
826 sx_xlock(&allproc_lock);
828 sx_xunlock(&allproc_lock);
831 mtx_lock_spin(&sched_lock);
832 if ((p->p_flag & P_STOPPED_SIG) &&
833 (p->p_suspcount == p->p_numthreads) &&
834 (p->p_flag & P_WAITED) == 0 &&
835 (p->p_flag & P_TRACED || options & WUNTRACED)) {
836 mtx_unlock_spin(&sched_lock);
837 p->p_flag |= P_WAITED;
838 sx_xunlock(&proctree_lock);
839 td->td_retval[0] = p->p_pid;
841 *status = W_STOPCODE(p->p_xstat);
844 sigqueue_take(p->p_ksi);
850 mtx_unlock_spin(&sched_lock);
851 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
852 sx_xunlock(&proctree_lock);
853 td->td_retval[0] = p->p_pid;
854 p->p_flag &= ~P_CONTINUED;
857 sigqueue_take(p->p_ksi);
868 sx_xunlock(&proctree_lock);
871 if (options & WNOHANG) {
872 sx_xunlock(&proctree_lock);
873 td->td_retval[0] = 0;
877 sx_xunlock(&proctree_lock);
878 if (q->p_flag & P_STATCHILD) {
879 q->p_flag &= ~P_STATCHILD;
882 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
890 * Make process 'parent' the new parent of process 'child'.
891 * Must be called with an exclusive hold of proctree lock.
894 proc_reparent(struct proc *child, struct proc *parent)
897 sx_assert(&proctree_lock, SX_XLOCKED);
898 PROC_LOCK_ASSERT(child, MA_OWNED);
899 if (child->p_pptr == parent)
902 PROC_LOCK(child->p_pptr);
903 sigqueue_take(child->p_ksi);
904 PROC_UNLOCK(child->p_pptr);
905 LIST_REMOVE(child, p_sibling);
906 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
907 child->p_pptr = parent;