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38 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
39 * $FreeBSD: src/sys/kern/kern_exit.c,v 1.92.2.11 2003/01/13 22:51:16 dillon Exp $
42 #include "opt_compat.h"
43 #include "opt_ktrace.h"
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/sysproto.h>
48 #include <sys/kernel.h>
49 #include <sys/malloc.h>
51 #include <sys/ktrace.h>
52 #include <sys/pioctl.h>
55 #include <sys/vnode.h>
56 #include <sys/resourcevar.h>
57 #include <sys/signalvar.h>
58 #include <sys/taskqueue.h>
59 #include <sys/ptrace.h>
60 #include <sys/acct.h> /* for acct_process() function prototype */
61 #include <sys/filedesc.h>
65 #include <sys/kern_syscall.h>
66 #include <sys/upcall.h>
68 #include <sys/unistd.h>
69 #include <sys/eventhandler.h>
70 #include <sys/dsched.h>
73 #include <vm/vm_param.h>
76 #include <vm/vm_map.h>
77 #include <vm/vm_extern.h>
80 #include <sys/refcount.h>
81 #include <sys/thread2.h>
82 #include <sys/sysref2.h>
83 #include <sys/mplock2.h>
85 static void reaplwps(void *context, int dummy);
86 static void reaplwp(struct lwp *lp);
87 static void killlwps(struct lwp *lp);
89 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
90 static MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
92 static struct lwkt_token deadlwp_token = LWKT_TOKEN_INITIALIZER(deadlwp_token);
95 * callout list for things to do at exit time
99 TAILQ_ENTRY(exitlist) next;
102 TAILQ_HEAD(exit_list_head, exitlist);
103 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list);
108 struct task *deadlwp_task[MAXCPU];
109 struct lwplist deadlwp_list[MAXCPU];
115 * SYS_EXIT_ARGS(int rval)
118 sys_exit(struct exit_args *uap)
120 exit1(W_EXITCODE(uap->rval, 0));
126 * Death of a lwp or process with optional bells and whistles.
131 sys_extexit(struct extexit_args *uap)
133 struct proc *p = curproc;
137 action = EXTEXIT_ACTION(uap->how);
138 who = EXTEXIT_WHO(uap->how);
140 /* Check parameters before we might perform some action */
153 error = copyout(&uap->status, uap->addr, sizeof(uap->status));
161 lwkt_gettoken(&p->p_token);
166 * Be sure only to perform a simple lwp exit if there is at
167 * least one more lwp in the proc, which will call exit1()
168 * later, otherwise the proc will be an UNDEAD and not even a
171 if (p->p_nthreads > 1) {
172 lwp_exit(0); /* called w/ p_token held */
175 /* else last lwp in proc: do the real thing */
177 default: /* to help gcc */
179 lwkt_reltoken(&p->p_token);
180 exit1(W_EXITCODE(uap->status, 0));
185 lwkt_reltoken(&p->p_token); /* safety */
189 * Kill all lwps associated with the current process except the
190 * current lwp. Return an error if we race another thread trying to
191 * do the same thing and lose the race.
193 * If forexec is non-zero the current thread and process flags are
194 * cleaned up so they can be reused.
196 * Caller must hold curproc->p_token
199 killalllwps(int forexec)
201 struct lwp *lp = curthread->td_lwp;
202 struct proc *p = lp->lwp_proc;
205 * Interlock against P_WEXIT. Only one of the process's thread
206 * is allowed to do the master exit.
208 if (p->p_flags & P_WEXIT)
210 p->p_flags |= P_WEXIT;
213 * Interlock with LWP_MP_WEXIT and kill any remaining LWPs
215 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
216 if (p->p_nthreads > 1)
220 * If doing this for an exec, clean up the remaining thread
221 * (us) for continuing operation after all the other threads
225 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
226 p->p_flags &= ~P_WEXIT;
232 * Kill all LWPs except the current one. Do not try to signal
233 * LWPs which have exited on their own or have already been
237 killlwps(struct lwp *lp)
239 struct proc *p = lp->lwp_proc;
243 * Kill the remaining LWPs. We must send the signal before setting
244 * LWP_MP_WEXIT. The setting of WEXIT is optional but helps reduce
245 * races. tlp must be held across the call as it might block and
246 * allow the target lwp to rip itself out from under our loop.
248 FOREACH_LWP_IN_PROC(tlp, p) {
250 lwkt_gettoken(&tlp->lwp_token);
251 if ((tlp->lwp_mpflags & LWP_MP_WEXIT) == 0) {
252 lwpsignal(p, tlp, SIGKILL);
253 atomic_set_int(&tlp->lwp_mpflags, LWP_MP_WEXIT);
255 lwkt_reltoken(&tlp->lwp_token);
260 * Wait for everything to clear out.
262 while (p->p_nthreads > 1) {
263 tsleep(&p->p_nthreads, 0, "killlwps", 0);
268 * Exit: deallocate address space and other resources, change proc state
269 * to zombie, and unlink proc from allproc and parent's lists. Save exit
270 * status and rusage for wait(). Check for child processes and orphan them.
275 struct thread *td = curthread;
276 struct proc *p = td->td_proc;
277 struct lwp *lp = td->td_lwp;
284 lwkt_gettoken(&p->p_token);
287 kprintf("init died (signal %d, exit %d)\n",
288 WTERMSIG(rv), WEXITSTATUS(rv));
289 panic("Going nowhere without my init!");
291 varsymset_clean(&p->p_varsymset);
292 lockuninit(&p->p_varsymset.vx_lock);
295 * Kill all lwps associated with the current process, return an
296 * error if we race another thread trying to do the same thing
299 error = killalllwps(0);
305 caps_exit(lp->lwp_thread);
307 /* are we a task leader? */
308 if (p == p->p_leader) {
309 struct kill_args killArgs;
310 killArgs.signum = SIGKILL;
313 killArgs.pid = q->p_pid;
315 * The interface for kill is better
316 * than the internal signal
323 tsleep((caddr_t)p, 0, "exit1", 0);
329 STOPEVENT(p, S_EXIT, rv);
330 p->p_flags |= P_POSTEXIT; /* stop procfs stepping */
333 * Check if any loadable modules need anything done at process exit.
334 * e.g. SYSV IPC stuff
335 * XXX what if one of these generates an error?
338 EVENTHANDLER_INVOKE(process_exit, p);
341 * XXX: imho, the eventhandler stuff is much cleaner than this.
342 * Maybe we should move everything to use eventhandler.
344 TAILQ_FOREACH(ep, &exit_list, next)
347 if (p->p_flags & P_PROFIL)
350 SIGEMPTYSET(p->p_siglist);
351 SIGEMPTYSET(lp->lwp_siglist);
352 if (timevalisset(&p->p_realtimer.it_value))
353 callout_stop_sync(&p->p_ithandle);
356 * Reset any sigio structures pointing to us as a result of
357 * F_SETOWN with our pid.
359 funsetownlst(&p->p_sigiolst);
362 * Close open files and release open-file table.
367 if(p->p_leader->p_peers) {
369 while(q->p_peers != p)
371 q->p_peers = p->p_peers;
372 wakeup((caddr_t)p->p_leader);
376 * XXX Shutdown SYSV semaphores
380 KKASSERT(p->p_numposixlocks == 0);
382 /* The next two chunks should probably be moved to vmspace_exit. */
386 * Release upcalls associated with this process
392 * Clean up data related to virtual kernel operation. Clean up
393 * any vkernel context related to the current lwp now so we can
397 vkernel_lwp_exit(lp);
402 * Release user portion of address space.
403 * This releases references to vnodes,
404 * which could cause I/O if the file has been unlinked.
405 * Need to do this early enough that we can still sleep.
406 * Can't free the entire vmspace as the kernel stack
407 * may be mapped within that space also.
409 * Processes sharing the same vmspace may exit in one order, and
410 * get cleaned up by vmspace_exit() in a different order. The
411 * last exiting process to reach this point releases as much of
412 * the environment as it can, and the last process cleaned up
413 * by vmspace_exit() (which decrements exitingcnt) cleans up the
416 vmspace_exitbump(vm);
417 sysref_put(&vm->vm_sysref);
419 if (SESS_LEADER(p)) {
420 struct session *sp = p->p_session;
424 * We are the controlling process. Signal the
425 * foreground process group, drain the controlling
426 * terminal, and revoke access to the controlling
429 * NOTE: while waiting for the process group to exit
430 * it is possible that one of the processes in the
431 * group will revoke the tty, so the ttyclosesession()
432 * function will re-check sp->s_ttyvp.
434 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
435 if (sp->s_ttyp->t_pgrp)
436 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
438 ttyclosesession(sp, 1); /* also revoke */
441 * Release the tty. If someone has it open via
442 * /dev/tty then close it (since they no longer can
443 * once we've NULL'd it out).
445 ttyclosesession(sp, 0);
448 * s_ttyp is not zero'd; we use this to indicate
449 * that the session once had a controlling terminal.
450 * (for logging and informational purposes)
455 fixjobc(p, p->p_pgrp, 0);
456 (void)acct_process(p);
462 ktrdestroy(&p->p_tracenode);
466 * Release reference to text vnode
468 if ((vtmp = p->p_textvp) != NULL) {
473 /* Release namecache handle to text file */
474 if (p->p_textnch.ncp)
475 cache_drop(&p->p_textnch);
478 * We have to handle PPWAIT here or proc_move_allproc_zombie()
479 * will block on the PHOLD() the parent is doing.
481 if (p->p_flags & P_PPWAIT) {
482 p->p_flags &= ~P_PPWAIT;
487 * Move the process to the zombie list. This will block
488 * until the process p_lock count reaches 0. The process will
489 * not be reaped until TDF_EXITING is set by cpu_thread_exit(),
490 * which is called from cpu_proc_exit().
492 proc_move_allproc_zombie(p);
495 * Reparent all of this process's children to the init process.
496 * We must hold initproc->p_token in order to mess with
497 * initproc->p_children. We already hold p->p_token (to remove
498 * the children from our list).
500 q = LIST_FIRST(&p->p_children);
502 lwkt_gettoken(&initproc->p_token);
503 while ((q = LIST_FIRST(&p->p_children)) != NULL) {
505 lwkt_gettoken(&q->p_token);
506 if (q != LIST_FIRST(&p->p_children)) {
507 lwkt_reltoken(&q->p_token);
511 LIST_REMOVE(q, p_sibling);
512 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
513 q->p_pptr = initproc;
514 q->p_sigparent = SIGCHLD;
517 * Traced processes are killed
518 * since their existence means someone is screwing up.
520 if (q->p_flags & P_TRACED) {
521 q->p_flags &= ~P_TRACED;
524 lwkt_reltoken(&q->p_token);
527 lwkt_reltoken(&initproc->p_token);
532 * Save exit status and final rusage info, adding in child rusage
533 * info and self times.
535 calcru_proc(p, &p->p_ru);
536 ruadd(&p->p_ru, &p->p_cru);
539 * notify interested parties of our demise.
541 KNOTE(&p->p_klist, NOTE_EXIT);
544 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
545 * flag set, or if the handler is set to SIG_IGN, notify process 1
546 * instead (and hope it will handle this situation).
548 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
549 struct proc *pp = p->p_pptr;
552 proc_reparent(p, initproc);
555 * If this was the last child of our parent, notify
556 * parent, so in case he was wait(2)ing, he will
557 * continue. This function interlocks with pptr->p_token.
559 if (LIST_EMPTY(&pp->p_children))
564 /* lwkt_gettoken(&proc_token); */
567 if (p->p_sigparent && q != initproc) {
568 ksignal(q, p->p_sigparent);
573 p->p_flags &= ~P_TRACED;
577 /* lwkt_reltoken(&proc_token); */
578 /* NOTE: p->p_pptr can get ripped out */
580 * cpu_exit is responsible for clearing curproc, since
581 * it is heavily integrated with the thread/switching sequence.
583 * Other substructures are freed from wait().
588 * Release the current user process designation on the process so
589 * the userland scheduler can work in someone else.
591 p->p_usched->release_curproc(lp);
594 * Finally, call machine-dependent code to release as many of the
595 * lwp's resources as we can and halt execution of this thread.
601 * Eventually called by every exiting LWP
603 * p->p_token must be held. mplock may be held and will be released.
606 lwp_exit(int masterexit)
608 struct thread *td = curthread;
609 struct lwp *lp = td->td_lwp;
610 struct proc *p = lp->lwp_proc;
614 * lwp_exit() may be called without setting LWP_MP_WEXIT, so
615 * make sure it is set here.
617 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
618 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
621 * Clean up any virtualization
624 vkernel_lwp_exit(lp);
627 * Clean up select/poll support
629 kqueue_terminate(&lp->lwp_kqueue);
632 * Clean up any syscall-cached ucred
635 crfree(td->td_ucred);
640 * Nobody actually wakes us when the lock
641 * count reaches zero, so just wait one tick.
643 while (lp->lwp_lock > 0)
644 tsleep(lp, 0, "lwpexit", 1);
646 /* Hand down resource usage to our proc */
647 ruadd(&p->p_ru, &lp->lwp_ru);
650 * If we don't hold the process until the LWP is reaped wait*()
651 * may try to dispose of its vmspace before all the LWPs have
652 * actually terminated.
657 * Do any remaining work that might block on us. We should be
658 * coded such that further blocking is ok after decrementing
659 * p_nthreads but don't take the chance.
661 dsched_exit_thread(td);
662 biosched_done(curthread);
665 * We have to use the reaper for all the LWPs except the one doing
666 * the master exit. The LWP doing the master exit can just be
667 * left on p_lwps and the process reaper will deal with it
668 * synchronously, which is much faster.
670 * Wakeup anyone waiting on p_nthreads to drop to 1 or 0.
672 * The process is left held until the reaper calls lwp_dispose() on
673 * the lp (after calling lwp_wait()).
675 if (masterexit == 0) {
676 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
678 if (p->p_nthreads <= 1)
680 lwkt_gettoken(&deadlwp_token);
681 LIST_INSERT_HEAD(&deadlwp_list[mycpuid], lp, u.lwp_reap_entry);
682 taskqueue_enqueue(taskqueue_thread[mycpuid],
683 deadlwp_task[mycpuid]);
684 lwkt_reltoken(&deadlwp_token);
687 if (p->p_nthreads <= 1)
692 * Release p_token. Issue the wakeup() on p_nthreads if necessary,
693 * as late as possible to give us a chance to actually deschedule and
694 * switch away before another cpu core hits reaplwp().
696 lwkt_reltoken(&p->p_token);
698 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.
710 * Returns non-zero on success, and zero if the caller needs to retry
714 lwp_wait(struct lwp *lp)
716 struct thread *td = lp->lwp_thread;;
718 KKASSERT(lwkt_preempted_proc() != lp);
721 * Wait until the lp has entered its low level exit and wait
722 * until other cores with refs on the lp (e.g. for ps or signaling)
725 if (lp->lwp_lock > 0) {
726 tsleep(lp, 0, "lwpwait1", 1);
731 * Wait until the thread is no longer references and no longer
732 * runnable or preempted (i.e. finishes its low level exit).
735 tsleep(td, 0, "lwpwait2", 1);
740 * The lwp's thread may still be in the middle
741 * of switching away, we can't rip its stack out from
742 * under it until TDF_EXITING is set and both
743 * TDF_RUNNING and TDF_PREEMPT_LOCK are clear.
744 * TDF_PREEMPT_LOCK must be checked because TDF_RUNNING
745 * will be cleared temporarily if a thread gets
748 * YYY no wakeup occurs, so we simply return failure
749 * and let the caller deal with sleeping and calling
752 if ((td->td_flags & (TDF_RUNNING |
754 TDF_EXITING)) != TDF_EXITING) {
755 tsleep(lp, 0, "lwpwait2", 1);
758 KASSERT((td->td_flags & (TDF_RUNQ|TDF_TSLEEPQ)) == 0,
759 ("lwp_wait: td %p (%s) still on run or sleep queue",
765 * Release the resources associated with a lwp.
766 * The lwp must be completely dead.
769 lwp_dispose(struct lwp *lp)
771 struct thread *td = lp->lwp_thread;;
773 KKASSERT(lwkt_preempted_proc() != lp);
774 KKASSERT(td->td_refs == 0);
775 KKASSERT((td->td_flags & (TDF_RUNNING |
777 TDF_EXITING)) == TDF_EXITING);
784 lp->lwp_thread = NULL;
785 lwkt_free_thread(td);
794 sys_wait4(struct wait_args *uap)
796 struct rusage rusage;
799 error = kern_wait(uap->pid, (uap->status ? &status : NULL),
800 uap->options, (uap->rusage ? &rusage : NULL),
801 &uap->sysmsg_result);
803 if (error == 0 && uap->status)
804 error = copyout(&status, uap->status, sizeof(*uap->status));
805 if (error == 0 && uap->rusage)
806 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage));
813 * wait_args(int pid, int *status, int options, struct rusage *rusage)
818 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res)
820 struct thread *td = curthread;
822 struct proc *q = td->td_proc;
830 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
833 lwkt_gettoken(&q->p_token);
836 * All sorts of things can change due to blocking so we have to loop
837 * all the way back up here.
839 * The problem is that if a process group is stopped and the parent
840 * is doing a wait*(..., WUNTRACED, ...), it will see the STOP
841 * of the child and then stop itself when it tries to return from the
842 * system call. When the process group is resumed the parent will
843 * then get the STOP status even though the child has now resumed
844 * (a followup wait*() will get the CONT status).
846 * Previously the CONT would overwrite the STOP because the tstop
847 * was handled within tsleep(), and the parent would only see
848 * the CONT when both are stopped and continued together. This little
849 * two-line hack restores this effect.
851 while (q->p_stat == SSTOP)
859 * NOTE: We don't want to break q's p_token in the loop for the
860 * case where no children are found or we risk breaking the
861 * interlock between child and parent.
863 LIST_FOREACH(p, &q->p_children, p_sibling) {
864 if (pid != WAIT_ANY &&
865 p->p_pid != pid && p->p_pgid != -pid) {
870 * This special case handles a kthread spawned by linux_clone
871 * (see linux_misc.c). The linux_wait4 and linux_waitpid
872 * functions need to be able to distinguish between waiting
873 * on a process and waiting on a thread. It is a thread if
874 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
875 * signifies we want to wait for threads and not processes.
877 if ((p->p_sigparent != SIGCHLD) ^
878 ((options & WLINUXCLONE) != 0)) {
883 if (p->p_stat == SZOMB) {
885 * We may go into SZOMB with threads still present.
886 * We must wait for them to exit before we can reap
887 * the master thread, otherwise we may race reaping
888 * non-master threads.
890 * Only this routine can remove a process from
891 * the zombie list and destroy it, use PACQUIREZOMB()
892 * to serialize us and loop if it blocks (interlocked
893 * by the parent's q->p_token).
895 * WARNING! (p) can be invalid when PHOLDZOMB(p)
896 * returns non-zero. Be sure not to
901 lwkt_gettoken(&p->p_token);
902 if (p->p_pptr != q) {
903 lwkt_reltoken(&p->p_token);
907 while (p->p_nthreads > 0) {
908 tsleep(&p->p_nthreads, 0, "lwpzomb", hz);
912 * Reap any LWPs left in p->p_lwps. This is usually
913 * just the last LWP. This must be done before
914 * we loop on p_lock since the lwps hold a ref on
915 * it as a vmspace interlock.
917 * Once that is accomplished p_nthreads had better
920 while ((lp = RB_ROOT(&p->p_lwp_tree)) != NULL) {
921 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
924 KKASSERT(p->p_nthreads == 0);
927 * Don't do anything really bad until all references
928 * to the process go away. This may include other
929 * LWPs which are still in the process of being
930 * reaped. We can't just pull the rug out from under
931 * them because they may still be using the VM space.
933 * Certain kernel facilities such as /proc will also
934 * put a hold on the process for short periods of
938 PSTALL(p, "reap3", 0);
940 /* Take care of our return values. */
942 p->p_usched->heuristic_exiting(td->td_lwp, p);
945 *status = p->p_xstat;
949 * If we got the child via a ptrace 'attach',
950 * we need to give it back to the old parent.
952 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
960 lwkt_reltoken(&p->p_token);
966 * Unlink the proc from its process group so that
967 * the following operations won't lead to an
968 * inconsistent state for processes running down
971 proc_remove_zombie(p);
972 lwkt_reltoken(&p->p_token);
976 ruadd(&q->p_cru, &p->p_ru);
979 * Decrement the count of procs running with this uid.
981 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
984 * Free up credentials.
990 * Remove unused arguments
994 if (pa && refcount_release(&pa->ar_ref)) {
1000 p->p_sigacts = NULL;
1001 if (ps && refcount_release(&ps->ps_refcnt)) {
1002 kfree(ps, M_SUBPROC);
1007 * Our exitingcount was incremented when the process
1008 * became a zombie, now that the process has been
1009 * removed from (almost) all lists we should be able
1010 * to safely destroy its vmspace. Wait for any current
1011 * holders to go away (so the vmspace remains stable),
1014 PSTALL(p, "reap4", 0);
1015 vmspace_exitfree(p);
1016 PSTALL(p, "reap5", 0);
1019 * NOTE: We have to officially release ZOMB in order
1020 * to ensure that a racing thread in kern_wait()
1021 * which blocked on ZOMB is woken up.
1026 atomic_add_int(&nprocs, -1);
1030 if (p->p_stat == SSTOP && (p->p_flags & P_WAITED) == 0 &&
1031 ((p->p_flags & P_TRACED) || (options & WUNTRACED))) {
1033 lwkt_gettoken(&p->p_token);
1034 if (p->p_pptr != q) {
1035 lwkt_reltoken(&p->p_token);
1039 if (p->p_stat != SSTOP ||
1040 (p->p_flags & P_WAITED) != 0 ||
1041 ((p->p_flags & P_TRACED) == 0 &&
1042 (options & WUNTRACED) == 0)) {
1043 lwkt_reltoken(&p->p_token);
1048 p->p_flags |= P_WAITED;
1051 p->p_usched->heuristic_exiting(td->td_lwp, p);
1053 *status = W_STOPCODE(p->p_xstat);
1054 /* Zero rusage so we get something consistent. */
1056 bzero(rusage, sizeof(*rusage));
1058 lwkt_reltoken(&p->p_token);
1062 if ((options & WCONTINUED) && (p->p_flags & P_CONTINUED)) {
1064 lwkt_gettoken(&p->p_token);
1065 if (p->p_pptr != q) {
1066 lwkt_reltoken(&p->p_token);
1070 if ((p->p_flags & P_CONTINUED) == 0) {
1071 lwkt_reltoken(&p->p_token);
1077 p->p_usched->heuristic_exiting(td->td_lwp, p);
1078 p->p_flags &= ~P_CONTINUED;
1083 lwkt_reltoken(&p->p_token);
1092 if (options & WNOHANG) {
1099 * Wait for signal - interlocked using q->p_token.
1101 error = tsleep(q, PCATCH, "wait", 0);
1104 lwkt_reltoken(&q->p_token);
1111 * Make process 'parent' the new parent of process 'child'.
1113 * p_children/p_sibling requires the parent's token, and
1114 * changing pptr requires the child's token, so we have to
1115 * get three tokens to do this operation.
1118 proc_reparent(struct proc *child, struct proc *parent)
1120 struct proc *opp = child->p_pptr;
1126 lwkt_gettoken(&opp->p_token);
1127 lwkt_gettoken(&child->p_token);
1128 lwkt_gettoken(&parent->p_token);
1129 KKASSERT(child->p_pptr == opp);
1130 LIST_REMOVE(child, p_sibling);
1131 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1132 child->p_pptr = parent;
1133 lwkt_reltoken(&parent->p_token);
1134 lwkt_reltoken(&child->p_token);
1135 lwkt_reltoken(&opp->p_token);
1141 * The next two functions are to handle adding/deleting items on the
1145 * Take the arguments given and put them onto the exit callout list,
1146 * However first make sure that it's not already there.
1147 * returns 0 on success.
1151 at_exit(exitlist_fn function)
1153 struct exitlist *ep;
1156 /* Be noisy if the programmer has lost track of things */
1157 if (rm_at_exit(function))
1158 kprintf("WARNING: exit callout entry (%p) already present\n",
1161 ep = kmalloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
1164 ep->function = function;
1165 TAILQ_INSERT_TAIL(&exit_list, ep, next);
1170 * Scan the exit callout list for the given item and remove it.
1171 * Returns the number of items removed (0 or 1)
1174 rm_at_exit(exitlist_fn function)
1176 struct exitlist *ep;
1178 TAILQ_FOREACH(ep, &exit_list, next) {
1179 if (ep->function == function) {
1180 TAILQ_REMOVE(&exit_list, ep, next);
1181 kfree(ep, M_ATEXIT);
1189 * LWP reaper related code.
1192 reaplwps(void *context, int dummy)
1194 struct lwplist *lwplist = context;
1197 lwkt_gettoken(&deadlwp_token);
1198 while ((lp = LIST_FIRST(lwplist))) {
1199 LIST_REMOVE(lp, u.lwp_reap_entry);
1202 lwkt_reltoken(&deadlwp_token);
1206 reaplwp(struct lwp *lp)
1208 while (lwp_wait(lp) == 0)
1218 for (cpu = 0; cpu < ncpus; cpu++) {
1219 LIST_INIT(&deadlwp_list[cpu]);
1220 deadlwp_task[cpu] = kmalloc(sizeof(*deadlwp_task[cpu]),
1221 M_DEVBUF, M_WAITOK);
1222 TASK_INIT(deadlwp_task[cpu], 0, reaplwps, &deadlwp_list[cpu]);
1226 SYSINIT(deadlwpinit, SI_SUB_CONFIGURE, SI_ORDER_ANY, deadlwp_init, NULL);