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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 the user portion of address space. The exitbump prevents
386 * the vmspace from being completely eradicated (using holdcnt).
387 * This releases references to vnodes, which could cause I/O if the
388 * file has been unlinked. We need to do this early enough that
389 * we can still sleep.
391 * We can't free the entire vmspace as the kernel stack may be mapped
392 * within that space also.
394 * Processes sharing the same vmspace may exit in one order, and
395 * get cleaned up by vmspace_exit() in a different order. The
396 * last exiting process to reach this point releases as much of
397 * the environment as it can, and the last process cleaned up
398 * by vmspace_exit() (which decrements exitingcnt) cleans up the
403 if (SESS_LEADER(p)) {
404 struct session *sp = p->p_session;
408 * We are the controlling process. Signal the
409 * foreground process group, drain the controlling
410 * terminal, and revoke access to the controlling
413 * NOTE: while waiting for the process group to exit
414 * it is possible that one of the processes in the
415 * group will revoke the tty, so the ttyclosesession()
416 * function will re-check sp->s_ttyvp.
418 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
419 if (sp->s_ttyp->t_pgrp)
420 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
422 ttyclosesession(sp, 1); /* also revoke */
425 * Release the tty. If someone has it open via
426 * /dev/tty then close it (since they no longer can
427 * once we've NULL'd it out).
429 ttyclosesession(sp, 0);
432 * s_ttyp is not zero'd; we use this to indicate
433 * that the session once had a controlling terminal.
434 * (for logging and informational purposes)
439 fixjobc(p, p->p_pgrp, 0);
440 (void)acct_process(p);
446 ktrdestroy(&p->p_tracenode);
450 * Release reference to text vnode
452 if ((vtmp = p->p_textvp) != NULL) {
457 /* Release namecache handle to text file */
458 if (p->p_textnch.ncp)
459 cache_drop(&p->p_textnch);
462 * We have to handle PPWAIT here or proc_move_allproc_zombie()
463 * will block on the PHOLD() the parent is doing.
465 * We are using the flag as an interlock so an atomic op is
466 * necessary to synchronize with the parent's cpu.
468 if (p->p_flags & P_PPWAIT) {
469 atomic_clear_int(&p->p_flags, P_PPWAIT);
474 * Move the process to the zombie list. This will block
475 * until the process p_lock count reaches 0. The process will
476 * not be reaped until TDF_EXITING is set by cpu_thread_exit(),
477 * which is called from cpu_proc_exit().
479 * Interlock against waiters using p_waitgen. We increment
480 * p_waitgen after completing the move of our process to the
483 * WARNING: pp becomes stale when we block, clear it now as a
486 proc_move_allproc_zombie(p);
488 atomic_add_long(&pp->p_waitgen, 1);
492 * Reparent all of this process's children to the init process.
493 * We must hold initproc->p_token in order to mess with
494 * initproc->p_children. We already hold p->p_token (to remove
495 * the children from our list).
497 q = LIST_FIRST(&p->p_children);
499 lwkt_gettoken(&initproc->p_token);
500 while ((q = LIST_FIRST(&p->p_children)) != NULL) {
502 lwkt_gettoken(&q->p_token);
503 if (q != LIST_FIRST(&p->p_children)) {
504 lwkt_reltoken(&q->p_token);
508 LIST_REMOVE(q, p_sibling);
509 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
510 q->p_pptr = initproc;
511 q->p_sigparent = SIGCHLD;
514 * Traced processes are killed
515 * since their existence means someone is screwing up.
517 if (q->p_flags & P_TRACED) {
518 q->p_flags &= ~P_TRACED;
521 lwkt_reltoken(&q->p_token);
524 lwkt_reltoken(&initproc->p_token);
529 * Save exit status and final rusage info, adding in child rusage
530 * info and self times.
532 calcru_proc(p, &p->p_ru);
533 ruadd(&p->p_ru, &p->p_cru);
536 * notify interested parties of our demise.
538 KNOTE(&p->p_klist, NOTE_EXIT);
541 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
542 * flag set, or if the handler is set to SIG_IGN, notify process 1
543 * instead (and hope it will handle this situation).
547 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
548 proc_reparent(p, initproc);
553 if (p->p_sigparent && pp != initproc) {
554 ksignal(pp, p->p_sigparent);
556 ksignal(pp, SIGCHLD);
558 p->p_flags &= ~P_TRACED;
562 * cpu_exit is responsible for clearing curproc, since
563 * it is heavily integrated with the thread/switching sequence.
565 * Other substructures are freed from wait().
570 * Finally, call machine-dependent code to release as many of the
571 * lwp's resources as we can and halt execution of this thread.
573 * pp is a wild pointer now but still the correct wakeup() target.
574 * lwp_exit() only uses it to send the wakeup() signal to the likely
575 * parent. Any reparenting race that occurs will get a signal
576 * automatically and not be an issue.
582 * Eventually called by every exiting LWP
584 * p->p_token must be held. mplock may be held and will be released.
587 lwp_exit(int masterexit, void *waddr)
589 struct thread *td = curthread;
590 struct lwp *lp = td->td_lwp;
591 struct proc *p = lp->lwp_proc;
595 * Release the current user process designation on the process so
596 * the userland scheduler can work in someone else.
598 p->p_usched->release_curproc(lp);
601 * lwp_exit() may be called without setting LWP_MP_WEXIT, so
602 * make sure it is set here.
604 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
605 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
608 * Clean up any virtualization
611 vkernel_lwp_exit(lp);
617 * Clean up select/poll support
619 kqueue_terminate(&lp->lwp_kqueue);
622 * Clean up any syscall-cached ucred
625 crfree(td->td_ucred);
630 * Nobody actually wakes us when the lock
631 * count reaches zero, so just wait one tick.
633 while (lp->lwp_lock > 0)
634 tsleep(lp, 0, "lwpexit", 1);
636 /* Hand down resource usage to our proc */
637 ruadd(&p->p_ru, &lp->lwp_ru);
640 * If we don't hold the process until the LWP is reaped wait*()
641 * may try to dispose of its vmspace before all the LWPs have
642 * actually terminated.
647 * Do any remaining work that might block on us. We should be
648 * coded such that further blocking is ok after decrementing
649 * p_nthreads but don't take the chance.
651 dsched_exit_thread(td);
652 biosched_done(curthread);
655 * We have to use the reaper for all the LWPs except the one doing
656 * the master exit. The LWP doing the master exit can just be
657 * left on p_lwps and the process reaper will deal with it
658 * synchronously, which is much faster.
660 * Wakeup anyone waiting on p_nthreads to drop to 1 or 0.
662 * The process is left held until the reaper calls lwp_dispose() on
663 * the lp (after calling lwp_wait()).
665 if (masterexit == 0) {
668 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
670 if ((p->p_flags & P_MAYBETHREADED) && p->p_nthreads <= 1)
672 lwkt_gettoken(&deadlwp_token[cpu]);
673 LIST_INSERT_HEAD(&deadlwp_list[cpu], lp, u.lwp_reap_entry);
674 taskqueue_enqueue(taskqueue_thread[cpu], deadlwp_task[cpu]);
675 lwkt_reltoken(&deadlwp_token[cpu]);
678 if ((p->p_flags & P_MAYBETHREADED) && p->p_nthreads <= 1)
683 * We no longer need p_token.
685 * Tell the userland scheduler that we are going away
687 lwkt_reltoken(&p->p_token);
688 p->p_usched->heuristic_exiting(lp, p);
691 * Issue late wakeups after releasing our token to give us a chance
692 * to deschedule and switch away before another cpu in a wait*()
693 * reaps us. This is done as late as possible to reduce contention.
696 wakeup(&p->p_nthreads);
704 * Wait until a lwp is completely dead. The final interlock in this drama
705 * is when TDF_EXITING is set in cpu_thread_exit() just before the final
708 * At the point TDF_EXITING is set a complete exit is accomplished when
709 * TDF_RUNNING and TDF_PREEMPT_LOCK are both clear. td_mpflags has two
710 * post-switch interlock flags that can be used to wait for the TDF_
713 * Returns non-zero on success, and zero if the caller needs to retry
717 lwp_wait(struct lwp *lp)
719 struct thread *td = lp->lwp_thread;
722 KKASSERT(lwkt_preempted_proc() != lp);
725 * This bit of code uses the thread destruction interlock
726 * managed by lwkt_switch_return() to wait for the lwp's
727 * thread to completely disengage.
729 * It is possible for us to race another cpu core so we
730 * have to do this correctly.
733 mpflags = td->td_mpflags;
735 if (mpflags & TDF_MP_EXITSIG)
737 tsleep_interlock(td, 0);
738 if (atomic_cmpset_int(&td->td_mpflags, mpflags,
739 mpflags | TDF_MP_EXITWAIT)) {
740 tsleep(td, PINTERLOCKED, "lwpxt", 0);
745 * We've already waited for the core exit but there can still
746 * be other refs from e.g. process scans and such.
748 if (lp->lwp_lock > 0) {
749 tsleep(lp, 0, "lwpwait1", 1);
753 tsleep(td, 0, "lwpwait2", 1);
758 * Now that we have the thread destruction interlock these flags
759 * really should already be cleaned up, keep a check for safety.
761 * We can't rip its stack out from under it until TDF_EXITING is
762 * set and both TDF_RUNNING and TDF_PREEMPT_LOCK are clear.
763 * TDF_PREEMPT_LOCK must be checked because TDF_RUNNING
764 * will be cleared temporarily if a thread gets preempted.
766 while ((td->td_flags & (TDF_RUNNING |
769 TDF_EXITING)) != TDF_EXITING) {
770 tsleep(lp, 0, "lwpwait3", 1);
774 KASSERT((td->td_flags & (TDF_RUNQ|TDF_TSLEEPQ)) == 0,
775 ("lwp_wait: td %p (%s) still on run or sleep queue",
781 * Release the resources associated with a lwp.
782 * The lwp must be completely dead.
785 lwp_dispose(struct lwp *lp)
787 struct thread *td = lp->lwp_thread;
789 KKASSERT(lwkt_preempted_proc() != lp);
790 KKASSERT(td->td_refs == 0);
791 KKASSERT((td->td_flags & (TDF_RUNNING |
794 TDF_EXITING)) == TDF_EXITING);
801 lp->lwp_thread = NULL;
802 lwkt_free_thread(td);
808 sys_wait4(struct wait_args *uap)
810 struct rusage rusage;
813 error = kern_wait(uap->pid, (uap->status ? &status : NULL),
814 uap->options, (uap->rusage ? &rusage : NULL),
815 &uap->sysmsg_result);
817 if (error == 0 && uap->status)
818 error = copyout(&status, uap->status, sizeof(*uap->status));
819 if (error == 0 && uap->rusage)
820 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage));
827 * wait_args(int pid, int *status, int options, struct rusage *rusage)
830 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res)
832 struct thread *td = curthread;
834 struct proc *q = td->td_proc;
843 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
847 * Protect the q->p_children list
849 lwkt_gettoken(&q->p_token);
852 * All sorts of things can change due to blocking so we have to loop
853 * all the way back up here.
855 * The problem is that if a process group is stopped and the parent
856 * is doing a wait*(..., WUNTRACED, ...), it will see the STOP
857 * of the child and then stop itself when it tries to return from the
858 * system call. When the process group is resumed the parent will
859 * then get the STOP status even though the child has now resumed
860 * (a followup wait*() will get the CONT status).
862 * Previously the CONT would overwrite the STOP because the tstop
863 * was handled within tsleep(), and the parent would only see
864 * the CONT when both are stopped and continued together. This little
865 * two-line hack restores this effect.
867 while (q->p_stat == SSTOP)
875 * NOTE: We don't want to break q's p_token in the loop for the
876 * case where no children are found or we risk breaking the
877 * interlock between child and parent.
879 waitgen = atomic_fetchadd_long(&q->p_waitgen, 0x80000000);
880 LIST_FOREACH(p, &q->p_children, p_sibling) {
881 if (pid != WAIT_ANY &&
882 p->p_pid != pid && p->p_pgid != -pid) {
887 * This special case handles a kthread spawned by linux_clone
888 * (see linux_misc.c). The linux_wait4 and linux_waitpid
889 * functions need to be able to distinguish between waiting
890 * on a process and waiting on a thread. It is a thread if
891 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
892 * signifies we want to wait for threads and not processes.
894 if ((p->p_sigparent != SIGCHLD) ^
895 ((options & WLINUXCLONE) != 0)) {
900 if (p->p_stat == SZOMB) {
902 * We may go into SZOMB with threads still present.
903 * We must wait for them to exit before we can reap
904 * the master thread, otherwise we may race reaping
905 * non-master threads.
907 * Only this routine can remove a process from
908 * the zombie list and destroy it, use PACQUIREZOMB()
909 * to serialize us and loop if it blocks (interlocked
910 * by the parent's q->p_token).
912 * WARNING! (p) can be invalid when PHOLDZOMB(p)
913 * returns non-zero. Be sure not to
918 lwkt_gettoken(&p->p_token);
919 if (p->p_pptr != q) {
920 lwkt_reltoken(&p->p_token);
924 while (p->p_nthreads > 0) {
925 tsleep(&p->p_nthreads, 0, "lwpzomb", hz);
929 * Reap any LWPs left in p->p_lwps. This is usually
930 * just the last LWP. This must be done before
931 * we loop on p_lock since the lwps hold a ref on
932 * it as a vmspace interlock.
934 * Once that is accomplished p_nthreads had better
937 while ((lp = RB_ROOT(&p->p_lwp_tree)) != NULL) {
938 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
941 KKASSERT(p->p_nthreads == 0);
944 * Don't do anything really bad until all references
945 * to the process go away. This may include other
946 * LWPs which are still in the process of being
947 * reaped. We can't just pull the rug out from under
948 * them because they may still be using the VM space.
950 * Certain kernel facilities such as /proc will also
951 * put a hold on the process for short periods of
955 PSTALL(p, "reap3", 0);
957 /* Take care of our return values. */
961 *status = p->p_xstat;
966 * If we got the child via a ptrace 'attach',
967 * we need to give it back to the old parent.
969 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
977 lwkt_reltoken(&p->p_token);
983 * Unlink the proc from its process group so that
984 * the following operations won't lead to an
985 * inconsistent state for processes running down
988 proc_remove_zombie(p);
990 lwkt_reltoken(&p->p_token);
994 ruadd(&q->p_cru, &p->p_ru);
997 * Decrement the count of procs running with this uid.
999 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
1002 * Free up credentials.
1008 * Remove unused arguments
1012 if (pa && refcount_release(&pa->ar_ref)) {
1018 p->p_sigacts = NULL;
1019 if (ps && refcount_release(&ps->ps_refcnt)) {
1020 kfree(ps, M_SUBPROC);
1025 * Our exitingcount was incremented when the process
1026 * became a zombie, now that the process has been
1027 * removed from (almost) all lists we should be able
1028 * to safely destroy its vmspace. Wait for any current
1029 * holders to go away (so the vmspace remains stable),
1032 PSTALL(p, "reap4", 0);
1033 vmspace_exitfree(p);
1034 PSTALL(p, "reap5", 0);
1037 * NOTE: We have to officially release ZOMB in order
1038 * to ensure that a racing thread in kern_wait()
1039 * which blocked on ZOMB is woken up.
1044 atomic_add_int(&nprocs, -1);
1048 if (p->p_stat == SSTOP && (p->p_flags & P_WAITED) == 0 &&
1049 ((p->p_flags & P_TRACED) || (options & WUNTRACED))) {
1051 lwkt_gettoken(&p->p_token);
1052 if (p->p_pptr != q) {
1053 lwkt_reltoken(&p->p_token);
1057 if (p->p_stat != SSTOP ||
1058 (p->p_flags & P_WAITED) != 0 ||
1059 ((p->p_flags & P_TRACED) == 0 &&
1060 (options & WUNTRACED) == 0)) {
1061 lwkt_reltoken(&p->p_token);
1066 p->p_flags |= P_WAITED;
1070 *status = W_STOPCODE(p->p_xstat);
1071 /* Zero rusage so we get something consistent. */
1073 bzero(rusage, sizeof(*rusage));
1075 lwkt_reltoken(&p->p_token);
1079 if ((options & WCONTINUED) && (p->p_flags & P_CONTINUED)) {
1081 lwkt_gettoken(&p->p_token);
1082 if (p->p_pptr != q) {
1083 lwkt_reltoken(&p->p_token);
1087 if ((p->p_flags & P_CONTINUED) == 0) {
1088 lwkt_reltoken(&p->p_token);
1094 p->p_flags &= ~P_CONTINUED;
1099 lwkt_reltoken(&p->p_token);
1108 if (options & WNOHANG) {
1115 * Wait for signal - interlocked using q->p_waitgen.
1118 while ((waitgen & 0x7FFFFFFF) == (q->p_waitgen & 0x7FFFFFFF)) {
1119 tsleep_interlock(q, PCATCH);
1120 waitgen = atomic_fetchadd_long(&q->p_waitgen, 0x80000000);
1121 if ((waitgen & 0x7FFFFFFF) == (q->p_waitgen & 0x7FFFFFFF)) {
1122 error = tsleep(q, PCATCH | PINTERLOCKED, "wait", 0);
1128 lwkt_reltoken(&q->p_token);
1135 * Change child's parent process to parent.
1137 * p_children/p_sibling requires the parent's token, and
1138 * changing pptr requires the child's token, so we have to
1139 * get three tokens to do this operation. We also need to
1140 * hold pointers that might get ripped out from under us to
1141 * preserve structural integrity.
1143 * It is possible to race another reparent or disconnect or other
1144 * similar operation. We must retry when this situation occurs.
1145 * Once we successfully reparent the process we no longer care
1149 proc_reparent(struct proc *child, struct proc *parent)
1154 while ((opp = child->p_pptr) != parent) {
1156 lwkt_gettoken(&opp->p_token);
1157 lwkt_gettoken(&child->p_token);
1158 lwkt_gettoken(&parent->p_token);
1159 if (child->p_pptr != opp) {
1160 lwkt_reltoken(&parent->p_token);
1161 lwkt_reltoken(&child->p_token);
1162 lwkt_reltoken(&opp->p_token);
1166 LIST_REMOVE(child, p_sibling);
1167 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1168 child->p_pptr = parent;
1169 lwkt_reltoken(&parent->p_token);
1170 lwkt_reltoken(&child->p_token);
1171 lwkt_reltoken(&opp->p_token);
1172 if (LIST_EMPTY(&opp->p_children))
1181 * The next two functions are to handle adding/deleting items on the
1185 * Take the arguments given and put them onto the exit callout list,
1186 * However first make sure that it's not already there.
1187 * returns 0 on success.
1191 at_exit(exitlist_fn function)
1193 struct exitlist *ep;
1196 /* Be noisy if the programmer has lost track of things */
1197 if (rm_at_exit(function))
1198 kprintf("WARNING: exit callout entry (%p) already present\n",
1201 ep = kmalloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
1204 ep->function = function;
1205 TAILQ_INSERT_TAIL(&exit_list, ep, next);
1210 * Scan the exit callout list for the given item and remove it.
1211 * Returns the number of items removed (0 or 1)
1214 rm_at_exit(exitlist_fn function)
1216 struct exitlist *ep;
1218 TAILQ_FOREACH(ep, &exit_list, next) {
1219 if (ep->function == function) {
1220 TAILQ_REMOVE(&exit_list, ep, next);
1221 kfree(ep, M_ATEXIT);
1229 * LWP reaper related code.
1232 reaplwps(void *context, int dummy)
1234 struct lwplist *lwplist = context;
1238 lwkt_gettoken(&deadlwp_token[cpu]);
1239 while ((lp = LIST_FIRST(lwplist))) {
1240 LIST_REMOVE(lp, u.lwp_reap_entry);
1243 lwkt_reltoken(&deadlwp_token[cpu]);
1247 reaplwp(struct lwp *lp)
1249 while (lwp_wait(lp) == 0)
1259 for (cpu = 0; cpu < ncpus; cpu++) {
1260 lwkt_token_init(&deadlwp_token[cpu], "deadlwpl");
1261 LIST_INIT(&deadlwp_list[cpu]);
1262 deadlwp_task[cpu] = kmalloc(sizeof(*deadlwp_task[cpu]),
1263 M_DEVBUF, M_WAITOK);
1264 TASK_INIT(deadlwp_task[cpu], 0, reaplwps, &deadlwp_list[cpu]);
1268 SYSINIT(deadlwpinit, SI_SUB_CONFIGURE, SI_ORDER_ANY, deadlwp_init, NULL);