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34 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
35 * $FreeBSD: src/sys/kern/kern_exit.c,v 1.92.2.11 2003/01/13 22:51:16 dillon Exp $
38 #include "opt_compat.h"
39 #include "opt_ktrace.h"
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/sysproto.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
47 #include <sys/ktrace.h>
48 #include <sys/pioctl.h>
51 #include <sys/vnode.h>
52 #include <sys/resourcevar.h>
53 #include <sys/signalvar.h>
54 #include <sys/taskqueue.h>
55 #include <sys/ptrace.h>
56 #include <sys/acct.h> /* for acct_process() function prototype */
57 #include <sys/filedesc.h>
61 #include <sys/kern_syscall.h>
62 #include <sys/unistd.h>
63 #include <sys/eventhandler.h>
64 #include <sys/dsched.h>
67 #include <vm/vm_param.h>
70 #include <vm/vm_map.h>
71 #include <vm/vm_extern.h>
74 #include <sys/refcount.h>
75 #include <sys/thread2.h>
76 #include <sys/sysref2.h>
77 #include <sys/mplock2.h>
79 #include <machine/vmm.h>
81 static void reaplwps(void *context, int dummy);
82 static void reaplwp(struct lwp *lp);
83 static void killlwps(struct lwp *lp);
85 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
88 * callout list for things to do at exit time
92 TAILQ_ENTRY(exitlist) next;
95 TAILQ_HEAD(exit_list_head, exitlist);
96 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list);
101 static struct task *deadlwp_task[MAXCPU];
102 static struct lwplist deadlwp_list[MAXCPU];
103 static struct lwkt_token deadlwp_token[MAXCPU];
109 * SYS_EXIT_ARGS(int rval)
112 sys_exit(struct exit_args *uap)
114 exit1(W_EXITCODE(uap->rval, 0));
120 * Death of a lwp or process with optional bells and whistles.
123 sys_extexit(struct extexit_args *uap)
125 struct proc *p = curproc;
129 action = EXTEXIT_ACTION(uap->how);
130 who = EXTEXIT_WHO(uap->how);
132 /* Check parameters before we might perform some action */
145 error = copyout(&uap->status, uap->addr, sizeof(uap->status));
153 lwkt_gettoken(&p->p_token);
158 * Be sure only to perform a simple lwp exit if there is at
159 * least one more lwp in the proc, which will call exit1()
160 * later, otherwise the proc will be an UNDEAD and not even a
163 if (p->p_nthreads > 1) {
164 lwp_exit(0, NULL); /* called w/ p_token held */
167 /* else last lwp in proc: do the real thing */
169 default: /* to help gcc */
171 lwkt_reltoken(&p->p_token);
172 exit1(W_EXITCODE(uap->status, 0));
177 lwkt_reltoken(&p->p_token); /* safety */
181 * Kill all lwps associated with the current process except the
182 * current lwp. Return an error if we race another thread trying to
183 * do the same thing and lose the race.
185 * If forexec is non-zero the current thread and process flags are
186 * cleaned up so they can be reused.
188 * Caller must hold curproc->p_token
191 killalllwps(int forexec)
193 struct lwp *lp = curthread->td_lwp;
194 struct proc *p = lp->lwp_proc;
197 * Interlock against P_WEXIT. Only one of the process's thread
198 * is allowed to do the master exit.
200 if (p->p_flags & P_WEXIT)
202 p->p_flags |= P_WEXIT;
205 * Interlock with LWP_MP_WEXIT and kill any remaining LWPs
207 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
208 if (p->p_nthreads > 1)
212 * If doing this for an exec, clean up the remaining thread
213 * (us) for continuing operation after all the other threads
217 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
218 p->p_flags &= ~P_WEXIT;
224 * Kill all LWPs except the current one. Do not try to signal
225 * LWPs which have exited on their own or have already been
229 killlwps(struct lwp *lp)
231 struct proc *p = lp->lwp_proc;
235 * Kill the remaining LWPs. We must send the signal before setting
236 * LWP_MP_WEXIT. The setting of WEXIT is optional but helps reduce
237 * races. tlp must be held across the call as it might block and
238 * allow the target lwp to rip itself out from under our loop.
240 FOREACH_LWP_IN_PROC(tlp, p) {
242 lwkt_gettoken(&tlp->lwp_token);
243 if ((tlp->lwp_mpflags & LWP_MP_WEXIT) == 0) {
244 lwpsignal(p, tlp, SIGKILL);
245 atomic_set_int(&tlp->lwp_mpflags, LWP_MP_WEXIT);
247 lwkt_reltoken(&tlp->lwp_token);
252 * Wait for everything to clear out.
254 while (p->p_nthreads > 1)
255 tsleep(&p->p_nthreads, 0, "killlwps", 0);
259 * Exit: deallocate address space and other resources, change proc state
260 * to zombie, and unlink proc from allproc and parent's lists. Save exit
261 * status and rusage for wait(). Check for child processes and orphan them.
266 struct thread *td = curthread;
267 struct proc *p = td->td_proc;
268 struct lwp *lp = td->td_lwp;
276 lwkt_gettoken(&p->p_token);
279 kprintf("init died (signal %d, exit %d)\n",
280 WTERMSIG(rv), WEXITSTATUS(rv));
281 panic("Going nowhere without my init!");
283 varsymset_clean(&p->p_varsymset);
284 lockuninit(&p->p_varsymset.vx_lock);
287 * Kill all lwps associated with the current process, return an
288 * error if we race another thread trying to do the same thing
291 error = killalllwps(0);
297 /* are we a task leader? */
298 if (p == p->p_leader) {
299 struct kill_args killArgs;
300 killArgs.signum = SIGKILL;
303 killArgs.pid = q->p_pid;
305 * The interface for kill is better
306 * than the internal signal
312 tsleep((caddr_t)p, 0, "exit1", 0);
318 STOPEVENT(p, S_EXIT, rv);
319 p->p_flags |= P_POSTEXIT; /* stop procfs stepping */
322 * Check if any loadable modules need anything done at process exit.
323 * e.g. SYSV IPC stuff
324 * XXX what if one of these generates an error?
327 EVENTHANDLER_INVOKE(process_exit, p);
330 * XXX: imho, the eventhandler stuff is much cleaner than this.
331 * Maybe we should move everything to use eventhandler.
333 TAILQ_FOREACH(ep, &exit_list, next)
336 if (p->p_flags & P_PROFIL)
339 SIGEMPTYSET(p->p_siglist);
340 SIGEMPTYSET(lp->lwp_siglist);
341 if (timevalisset(&p->p_realtimer.it_value))
342 callout_stop_sync(&p->p_ithandle);
345 * Reset any sigio structures pointing to us as a result of
346 * F_SETOWN with our pid.
348 funsetownlst(&p->p_sigiolst);
351 * Close open files and release open-file table.
356 if (p->p_leader->p_peers) {
358 while(q->p_peers != p)
360 q->p_peers = p->p_peers;
361 wakeup((caddr_t)p->p_leader);
365 * XXX Shutdown SYSV semaphores
369 KKASSERT(p->p_numposixlocks == 0);
371 /* The next two chunks should probably be moved to vmspace_exit. */
375 * Clean up data related to virtual kernel operation. Clean up
376 * any vkernel context related to the current lwp now so we can
380 vkernel_lwp_exit(lp);
385 * Release user portion of address space.
386 * This releases references to vnodes,
387 * which could cause I/O if the file has been unlinked.
388 * Need to do this early enough that we can still sleep.
389 * Can't free the entire vmspace as the kernel stack
390 * may be mapped within that space also.
392 * Processes sharing the same vmspace may exit in one order, and
393 * get cleaned up by vmspace_exit() in a different order. The
394 * last exiting process to reach this point releases as much of
395 * the environment as it can, and the last process cleaned up
396 * by vmspace_exit() (which decrements exitingcnt) cleans up the
399 vmspace_exitbump(vm);
400 sysref_put(&vm->vm_sysref);
402 if (SESS_LEADER(p)) {
403 struct session *sp = p->p_session;
407 * We are the controlling process. Signal the
408 * foreground process group, drain the controlling
409 * terminal, and revoke access to the controlling
412 * NOTE: while waiting for the process group to exit
413 * it is possible that one of the processes in the
414 * group will revoke the tty, so the ttyclosesession()
415 * function will re-check sp->s_ttyvp.
417 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
418 if (sp->s_ttyp->t_pgrp)
419 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
421 ttyclosesession(sp, 1); /* also revoke */
424 * Release the tty. If someone has it open via
425 * /dev/tty then close it (since they no longer can
426 * once we've NULL'd it out).
428 ttyclosesession(sp, 0);
431 * s_ttyp is not zero'd; we use this to indicate
432 * that the session once had a controlling terminal.
433 * (for logging and informational purposes)
438 fixjobc(p, p->p_pgrp, 0);
439 (void)acct_process(p);
445 ktrdestroy(&p->p_tracenode);
449 * Release reference to text vnode
451 if ((vtmp = p->p_textvp) != NULL) {
456 /* Release namecache handle to text file */
457 if (p->p_textnch.ncp)
458 cache_drop(&p->p_textnch);
461 * We have to handle PPWAIT here or proc_move_allproc_zombie()
462 * will block on the PHOLD() the parent is doing.
464 * We are using the flag as an interlock so an atomic op is
465 * necessary to synchronize with the parent's cpu.
467 if (p->p_flags & P_PPWAIT) {
468 atomic_clear_int(&p->p_flags, P_PPWAIT);
473 * Move the process to the zombie list. This will block
474 * until the process p_lock count reaches 0. The process will
475 * not be reaped until TDF_EXITING is set by cpu_thread_exit(),
476 * which is called from cpu_proc_exit().
478 * Interlock against waiters using p_waitgen. We increment
479 * p_waitgen after completing the move of our process to the
482 * WARNING: pp becomes stale when we block, clear it now as a
485 proc_move_allproc_zombie(p);
487 atomic_add_long(&pp->p_waitgen, 1);
491 * Reparent all of this process's children to the init process.
492 * We must hold initproc->p_token in order to mess with
493 * initproc->p_children. We already hold p->p_token (to remove
494 * the children from our list).
496 q = LIST_FIRST(&p->p_children);
498 lwkt_gettoken(&initproc->p_token);
499 while ((q = LIST_FIRST(&p->p_children)) != NULL) {
501 lwkt_gettoken(&q->p_token);
502 if (q != LIST_FIRST(&p->p_children)) {
503 lwkt_reltoken(&q->p_token);
507 LIST_REMOVE(q, p_sibling);
508 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
509 q->p_pptr = initproc;
510 q->p_sigparent = SIGCHLD;
513 * Traced processes are killed
514 * since their existence means someone is screwing up.
516 if (q->p_flags & P_TRACED) {
517 q->p_flags &= ~P_TRACED;
520 lwkt_reltoken(&q->p_token);
523 lwkt_reltoken(&initproc->p_token);
528 * Save exit status and final rusage info, adding in child rusage
529 * info and self times.
531 calcru_proc(p, &p->p_ru);
532 ruadd(&p->p_ru, &p->p_cru);
535 * notify interested parties of our demise.
537 KNOTE(&p->p_klist, NOTE_EXIT);
540 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
541 * flag set, or if the handler is set to SIG_IGN, notify process 1
542 * instead (and hope it will handle this situation).
546 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
547 proc_reparent(p, initproc);
552 if (p->p_sigparent && pp != initproc) {
553 ksignal(pp, p->p_sigparent);
555 ksignal(pp, SIGCHLD);
557 p->p_flags &= ~P_TRACED;
561 * cpu_exit is responsible for clearing curproc, since
562 * it is heavily integrated with the thread/switching sequence.
564 * Other substructures are freed from wait().
569 * Finally, call machine-dependent code to release as many of the
570 * lwp's resources as we can and halt execution of this thread.
572 * pp is a wild pointer now but still the correct wakeup() target.
573 * lwp_exit() only uses it to send the wakeup() signal to the likely
574 * parent. Any reparenting race that occurs will get a signal
575 * automatically and not be an issue.
581 * Eventually called by every exiting LWP
583 * p->p_token must be held. mplock may be held and will be released.
586 lwp_exit(int masterexit, void *waddr)
588 struct thread *td = curthread;
589 struct lwp *lp = td->td_lwp;
590 struct proc *p = lp->lwp_proc;
594 * Release the current user process designation on the process so
595 * the userland scheduler can work in someone else.
597 p->p_usched->release_curproc(lp);
600 * lwp_exit() may be called without setting LWP_MP_WEXIT, so
601 * make sure it is set here.
603 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
604 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
607 * Clean up any virtualization
610 vkernel_lwp_exit(lp);
616 * Clean up select/poll support
618 kqueue_terminate(&lp->lwp_kqueue);
621 * Clean up any syscall-cached ucred
624 crfree(td->td_ucred);
629 * Nobody actually wakes us when the lock
630 * count reaches zero, so just wait one tick.
632 while (lp->lwp_lock > 0)
633 tsleep(lp, 0, "lwpexit", 1);
635 /* Hand down resource usage to our proc */
636 ruadd(&p->p_ru, &lp->lwp_ru);
639 * If we don't hold the process until the LWP is reaped wait*()
640 * may try to dispose of its vmspace before all the LWPs have
641 * actually terminated.
646 * Do any remaining work that might block on us. We should be
647 * coded such that further blocking is ok after decrementing
648 * p_nthreads but don't take the chance.
650 dsched_exit_thread(td);
651 biosched_done(curthread);
654 * We have to use the reaper for all the LWPs except the one doing
655 * the master exit. The LWP doing the master exit can just be
656 * left on p_lwps and the process reaper will deal with it
657 * synchronously, which is much faster.
659 * Wakeup anyone waiting on p_nthreads to drop to 1 or 0.
661 * The process is left held until the reaper calls lwp_dispose() on
662 * the lp (after calling lwp_wait()).
664 if (masterexit == 0) {
667 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
669 if ((p->p_flags & P_MAYBETHREADED) && p->p_nthreads <= 1)
671 lwkt_gettoken(&deadlwp_token[cpu]);
672 LIST_INSERT_HEAD(&deadlwp_list[cpu], lp, u.lwp_reap_entry);
673 taskqueue_enqueue(taskqueue_thread[cpu], deadlwp_task[cpu]);
674 lwkt_reltoken(&deadlwp_token[cpu]);
677 if ((p->p_flags & P_MAYBETHREADED) && p->p_nthreads <= 1)
682 * We no longer need p_token.
684 * Tell the userland scheduler that we are going away
686 lwkt_reltoken(&p->p_token);
687 p->p_usched->heuristic_exiting(lp, p);
690 * Issue late wakeups after releasing our token to give us a chance
691 * to deschedule and switch away before another cpu in a wait*()
692 * reaps us. This is done as late as possible to reduce contention.
695 wakeup(&p->p_nthreads);
703 * Wait until a lwp is completely dead. The final interlock in this drama
704 * is when TDF_EXITING is set in cpu_thread_exit() just before the final
707 * At the point TDF_EXITING is set a complete exit is accomplished when
708 * TDF_RUNNING and TDF_PREEMPT_LOCK are both clear. td_mpflags has two
709 * post-switch interlock flags that can be used to wait for the TDF_
712 * Returns non-zero on success, and zero if the caller needs to retry
716 lwp_wait(struct lwp *lp)
718 struct thread *td = lp->lwp_thread;
721 KKASSERT(lwkt_preempted_proc() != lp);
724 * This bit of code uses the thread destruction interlock
725 * managed by lwkt_switch_return() to wait for the lwp's
726 * thread to completely disengage.
728 * It is possible for us to race another cpu core so we
729 * have to do this correctly.
732 mpflags = td->td_mpflags;
734 if (mpflags & TDF_MP_EXITSIG)
736 tsleep_interlock(td, 0);
737 if (atomic_cmpset_int(&td->td_mpflags, mpflags,
738 mpflags | TDF_MP_EXITWAIT)) {
739 tsleep(td, PINTERLOCKED, "lwpxt", 0);
744 * We've already waited for the core exit but there can still
745 * be other refs from e.g. process scans and such.
747 if (lp->lwp_lock > 0) {
748 tsleep(lp, 0, "lwpwait1", 1);
752 tsleep(td, 0, "lwpwait2", 1);
757 * Now that we have the thread destruction interlock these flags
758 * really should already be cleaned up, keep a check for safety.
760 * We can't rip its stack out from under it until TDF_EXITING is
761 * set and both TDF_RUNNING and TDF_PREEMPT_LOCK are clear.
762 * TDF_PREEMPT_LOCK must be checked because TDF_RUNNING
763 * will be cleared temporarily if a thread gets preempted.
765 while ((td->td_flags & (TDF_RUNNING |
767 TDF_EXITING)) != TDF_EXITING) {
768 tsleep(lp, 0, "lwpwait3", 1);
772 KASSERT((td->td_flags & (TDF_RUNQ|TDF_TSLEEPQ)) == 0,
773 ("lwp_wait: td %p (%s) still on run or sleep queue",
779 * Release the resources associated with a lwp.
780 * The lwp must be completely dead.
783 lwp_dispose(struct lwp *lp)
785 struct thread *td = lp->lwp_thread;
787 KKASSERT(lwkt_preempted_proc() != lp);
788 KKASSERT(td->td_refs == 0);
789 KKASSERT((td->td_flags & (TDF_RUNNING |
791 TDF_EXITING)) == TDF_EXITING);
798 lp->lwp_thread = NULL;
799 lwkt_free_thread(td);
805 sys_wait4(struct wait_args *uap)
807 struct rusage rusage;
810 error = kern_wait(uap->pid, (uap->status ? &status : NULL),
811 uap->options, (uap->rusage ? &rusage : NULL),
812 &uap->sysmsg_result);
814 if (error == 0 && uap->status)
815 error = copyout(&status, uap->status, sizeof(*uap->status));
816 if (error == 0 && uap->rusage)
817 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage));
824 * wait_args(int pid, int *status, int options, struct rusage *rusage)
827 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res)
829 struct thread *td = curthread;
831 struct proc *q = td->td_proc;
840 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
844 * Protect the q->p_children list
846 lwkt_gettoken(&q->p_token);
849 * All sorts of things can change due to blocking so we have to loop
850 * all the way back up here.
852 * The problem is that if a process group is stopped and the parent
853 * is doing a wait*(..., WUNTRACED, ...), it will see the STOP
854 * of the child and then stop itself when it tries to return from the
855 * system call. When the process group is resumed the parent will
856 * then get the STOP status even though the child has now resumed
857 * (a followup wait*() will get the CONT status).
859 * Previously the CONT would overwrite the STOP because the tstop
860 * was handled within tsleep(), and the parent would only see
861 * the CONT when both are stopped and continued together. This little
862 * two-line hack restores this effect.
864 while (q->p_stat == SSTOP)
872 * NOTE: We don't want to break q's p_token in the loop for the
873 * case where no children are found or we risk breaking the
874 * interlock between child and parent.
876 waitgen = atomic_fetchadd_long(&q->p_waitgen, 0x80000000);
877 LIST_FOREACH(p, &q->p_children, p_sibling) {
878 if (pid != WAIT_ANY &&
879 p->p_pid != pid && p->p_pgid != -pid) {
884 * This special case handles a kthread spawned by linux_clone
885 * (see linux_misc.c). The linux_wait4 and linux_waitpid
886 * functions need to be able to distinguish between waiting
887 * on a process and waiting on a thread. It is a thread if
888 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
889 * signifies we want to wait for threads and not processes.
891 if ((p->p_sigparent != SIGCHLD) ^
892 ((options & WLINUXCLONE) != 0)) {
897 if (p->p_stat == SZOMB) {
899 * We may go into SZOMB with threads still present.
900 * We must wait for them to exit before we can reap
901 * the master thread, otherwise we may race reaping
902 * non-master threads.
904 * Only this routine can remove a process from
905 * the zombie list and destroy it, use PACQUIREZOMB()
906 * to serialize us and loop if it blocks (interlocked
907 * by the parent's q->p_token).
909 * WARNING! (p) can be invalid when PHOLDZOMB(p)
910 * returns non-zero. Be sure not to
915 lwkt_gettoken(&p->p_token);
916 if (p->p_pptr != q) {
917 lwkt_reltoken(&p->p_token);
921 while (p->p_nthreads > 0) {
922 tsleep(&p->p_nthreads, 0, "lwpzomb", hz);
926 * Reap any LWPs left in p->p_lwps. This is usually
927 * just the last LWP. This must be done before
928 * we loop on p_lock since the lwps hold a ref on
929 * it as a vmspace interlock.
931 * Once that is accomplished p_nthreads had better
934 while ((lp = RB_ROOT(&p->p_lwp_tree)) != NULL) {
935 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
938 KKASSERT(p->p_nthreads == 0);
941 * Don't do anything really bad until all references
942 * to the process go away. This may include other
943 * LWPs which are still in the process of being
944 * reaped. We can't just pull the rug out from under
945 * them because they may still be using the VM space.
947 * Certain kernel facilities such as /proc will also
948 * put a hold on the process for short periods of
952 PSTALL(p, "reap3", 0);
954 /* Take care of our return values. */
958 *status = p->p_xstat;
963 * If we got the child via a ptrace 'attach',
964 * we need to give it back to the old parent.
966 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
974 lwkt_reltoken(&p->p_token);
980 * Unlink the proc from its process group so that
981 * the following operations won't lead to an
982 * inconsistent state for processes running down
985 proc_remove_zombie(p);
986 lwkt_reltoken(&p->p_token);
990 ruadd(&q->p_cru, &p->p_ru);
993 * Decrement the count of procs running with this uid.
995 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
998 * Free up credentials.
1004 * Remove unused arguments
1008 if (pa && refcount_release(&pa->ar_ref)) {
1014 p->p_sigacts = NULL;
1015 if (ps && refcount_release(&ps->ps_refcnt)) {
1016 kfree(ps, M_SUBPROC);
1021 * Our exitingcount was incremented when the process
1022 * became a zombie, now that the process has been
1023 * removed from (almost) all lists we should be able
1024 * to safely destroy its vmspace. Wait for any current
1025 * holders to go away (so the vmspace remains stable),
1028 PSTALL(p, "reap4", 0);
1029 vmspace_exitfree(p);
1030 PSTALL(p, "reap5", 0);
1033 * NOTE: We have to officially release ZOMB in order
1034 * to ensure that a racing thread in kern_wait()
1035 * which blocked on ZOMB is woken up.
1040 atomic_add_int(&nprocs, -1);
1044 if (p->p_stat == SSTOP && (p->p_flags & P_WAITED) == 0 &&
1045 ((p->p_flags & P_TRACED) || (options & WUNTRACED))) {
1047 lwkt_gettoken(&p->p_token);
1048 if (p->p_pptr != q) {
1049 lwkt_reltoken(&p->p_token);
1053 if (p->p_stat != SSTOP ||
1054 (p->p_flags & P_WAITED) != 0 ||
1055 ((p->p_flags & P_TRACED) == 0 &&
1056 (options & WUNTRACED) == 0)) {
1057 lwkt_reltoken(&p->p_token);
1062 p->p_flags |= P_WAITED;
1066 *status = W_STOPCODE(p->p_xstat);
1067 /* Zero rusage so we get something consistent. */
1069 bzero(rusage, sizeof(*rusage));
1071 lwkt_reltoken(&p->p_token);
1075 if ((options & WCONTINUED) && (p->p_flags & P_CONTINUED)) {
1077 lwkt_gettoken(&p->p_token);
1078 if (p->p_pptr != q) {
1079 lwkt_reltoken(&p->p_token);
1083 if ((p->p_flags & P_CONTINUED) == 0) {
1084 lwkt_reltoken(&p->p_token);
1090 p->p_flags &= ~P_CONTINUED;
1095 lwkt_reltoken(&p->p_token);
1104 if (options & WNOHANG) {
1111 * Wait for signal - interlocked using q->p_waitgen.
1114 while ((waitgen & 0x7FFFFFFF) == (q->p_waitgen & 0x7FFFFFFF)) {
1115 tsleep_interlock(q, PCATCH);
1116 waitgen = atomic_fetchadd_long(&q->p_waitgen, 0x80000000);
1117 if ((waitgen & 0x7FFFFFFF) == (q->p_waitgen & 0x7FFFFFFF)) {
1118 error = tsleep(q, PCATCH | PINTERLOCKED, "wait", 0);
1124 lwkt_reltoken(&q->p_token);
1131 * Change child's parent process to parent.
1133 * p_children/p_sibling requires the parent's token, and
1134 * changing pptr requires the child's token, so we have to
1135 * get three tokens to do this operation. We also need to
1136 * hold pointers that might get ripped out from under us to
1137 * preserve structural integrity.
1139 * It is possible to race another reparent or disconnect or other
1140 * similar operation. We must retry when this situation occurs.
1141 * Once we successfully reparent the process we no longer care
1145 proc_reparent(struct proc *child, struct proc *parent)
1150 while ((opp = child->p_pptr) != parent) {
1152 lwkt_gettoken(&opp->p_token);
1153 lwkt_gettoken(&child->p_token);
1154 lwkt_gettoken(&parent->p_token);
1155 if (child->p_pptr != opp) {
1156 lwkt_reltoken(&parent->p_token);
1157 lwkt_reltoken(&child->p_token);
1158 lwkt_reltoken(&opp->p_token);
1162 LIST_REMOVE(child, p_sibling);
1163 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1164 child->p_pptr = parent;
1165 lwkt_reltoken(&parent->p_token);
1166 lwkt_reltoken(&child->p_token);
1167 lwkt_reltoken(&opp->p_token);
1168 if (LIST_EMPTY(&opp->p_children))
1177 * The next two functions are to handle adding/deleting items on the
1181 * Take the arguments given and put them onto the exit callout list,
1182 * However first make sure that it's not already there.
1183 * returns 0 on success.
1187 at_exit(exitlist_fn function)
1189 struct exitlist *ep;
1192 /* Be noisy if the programmer has lost track of things */
1193 if (rm_at_exit(function))
1194 kprintf("WARNING: exit callout entry (%p) already present\n",
1197 ep = kmalloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
1200 ep->function = function;
1201 TAILQ_INSERT_TAIL(&exit_list, ep, next);
1206 * Scan the exit callout list for the given item and remove it.
1207 * Returns the number of items removed (0 or 1)
1210 rm_at_exit(exitlist_fn function)
1212 struct exitlist *ep;
1214 TAILQ_FOREACH(ep, &exit_list, next) {
1215 if (ep->function == function) {
1216 TAILQ_REMOVE(&exit_list, ep, next);
1217 kfree(ep, M_ATEXIT);
1225 * LWP reaper related code.
1228 reaplwps(void *context, int dummy)
1230 struct lwplist *lwplist = context;
1234 lwkt_gettoken(&deadlwp_token[cpu]);
1235 while ((lp = LIST_FIRST(lwplist))) {
1236 LIST_REMOVE(lp, u.lwp_reap_entry);
1239 lwkt_reltoken(&deadlwp_token[cpu]);
1243 reaplwp(struct lwp *lp)
1245 while (lwp_wait(lp) == 0)
1255 for (cpu = 0; cpu < ncpus; cpu++) {
1256 lwkt_token_init(&deadlwp_token[cpu], "deadlwpl");
1257 LIST_INIT(&deadlwp_list[cpu]);
1258 deadlwp_task[cpu] = kmalloc(sizeof(*deadlwp_task[cpu]),
1259 M_DEVBUF, M_WAITOK);
1260 TASK_INIT(deadlwp_task[cpu], 0, reaplwps, &deadlwp_list[cpu]);
1264 SYSINIT(deadlwpinit, SI_SUB_CONFIGURE, SI_ORDER_ANY, deadlwp_init, NULL);