v2.6.22.24-op1
[linux-2.6.22.y-op.git] / kernel / exit.c
blob369dae2ad719c6f6580d6a46422964f8c1a4513f
1 /*
2 * linux/kernel/exit.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
7 #include <linux/mm.h>
8 #include <linux/slab.h>
9 #include <linux/interrupt.h>
10 #include <linux/module.h>
11 #include <linux/capability.h>
12 #include <linux/completion.h>
13 #include <linux/personality.h>
14 #include <linux/tty.h>
15 #include <linux/mnt_namespace.h>
16 #include <linux/key.h>
17 #include <linux/security.h>
18 #include <linux/cpu.h>
19 #include <linux/acct.h>
20 #include <linux/tsacct_kern.h>
21 #include <linux/file.h>
22 #include <linux/binfmts.h>
23 #include <linux/nsproxy.h>
24 #include <linux/pid_namespace.h>
25 #include <linux/ptrace.h>
26 #include <linux/profile.h>
27 #include <linux/signalfd.h>
28 #include <linux/mount.h>
29 #include <linux/proc_fs.h>
30 #include <linux/kthread.h>
31 #include <linux/mempolicy.h>
32 #include <linux/taskstats_kern.h>
33 #include <linux/delayacct.h>
34 #include <linux/cpuset.h>
35 #include <linux/syscalls.h>
36 #include <linux/signal.h>
37 #include <linux/posix-timers.h>
38 #include <linux/cn_proc.h>
39 #include <linux/mutex.h>
40 #include <linux/futex.h>
41 #include <linux/compat.h>
42 #include <linux/pipe_fs_i.h>
43 #include <linux/audit.h> /* for audit_free() */
44 #include <linux/resource.h>
45 #include <linux/blkdev.h>
46 #include <linux/task_io_accounting_ops.h>
48 #include <asm/uaccess.h>
49 #include <asm/unistd.h>
50 #include <asm/pgtable.h>
51 #include <asm/mmu_context.h>
53 extern void sem_exit (void);
55 static void exit_mm(struct task_struct * tsk);
57 static void __unhash_process(struct task_struct *p)
59 nr_threads--;
60 detach_pid(p, PIDTYPE_PID);
61 if (thread_group_leader(p)) {
62 detach_pid(p, PIDTYPE_PGID);
63 detach_pid(p, PIDTYPE_SID);
65 list_del_rcu(&p->tasks);
66 __get_cpu_var(process_counts)--;
68 list_del_rcu(&p->thread_group);
69 remove_parent(p);
73 * This function expects the tasklist_lock write-locked.
75 static void __exit_signal(struct task_struct *tsk)
77 struct signal_struct *sig = tsk->signal;
78 struct sighand_struct *sighand;
80 BUG_ON(!sig);
81 BUG_ON(!atomic_read(&sig->count));
83 rcu_read_lock();
84 sighand = rcu_dereference(tsk->sighand);
85 spin_lock(&sighand->siglock);
88 * Notify that this sighand has been detached. This must
89 * be called with the tsk->sighand lock held. Also, this
90 * access tsk->sighand internally, so it must be called
91 * before tsk->sighand is reset.
93 signalfd_detach_locked(tsk);
95 posix_cpu_timers_exit(tsk);
96 if (atomic_dec_and_test(&sig->count))
97 posix_cpu_timers_exit_group(tsk);
98 else {
100 * If there is any task waiting for the group exit
101 * then notify it:
103 if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) {
104 wake_up_process(sig->group_exit_task);
105 sig->group_exit_task = NULL;
107 if (tsk == sig->curr_target)
108 sig->curr_target = next_thread(tsk);
110 * Accumulate here the counters for all threads but the
111 * group leader as they die, so they can be added into
112 * the process-wide totals when those are taken.
113 * The group leader stays around as a zombie as long
114 * as there are other threads. When it gets reaped,
115 * the exit.c code will add its counts into these totals.
116 * We won't ever get here for the group leader, since it
117 * will have been the last reference on the signal_struct.
119 sig->utime = cputime_add(sig->utime, tsk->utime);
120 sig->stime = cputime_add(sig->stime, tsk->stime);
121 sig->min_flt += tsk->min_flt;
122 sig->maj_flt += tsk->maj_flt;
123 sig->nvcsw += tsk->nvcsw;
124 sig->nivcsw += tsk->nivcsw;
125 sig->sched_time += tsk->sched_time;
126 sig->inblock += task_io_get_inblock(tsk);
127 sig->oublock += task_io_get_oublock(tsk);
128 sig = NULL; /* Marker for below. */
131 __unhash_process(tsk);
133 tsk->signal = NULL;
134 tsk->sighand = NULL;
135 spin_unlock(&sighand->siglock);
136 rcu_read_unlock();
138 __cleanup_sighand(sighand);
139 clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
140 flush_sigqueue(&tsk->pending);
141 if (sig) {
142 flush_sigqueue(&sig->shared_pending);
143 taskstats_tgid_free(sig);
144 __cleanup_signal(sig);
148 static void delayed_put_task_struct(struct rcu_head *rhp)
150 put_task_struct(container_of(rhp, struct task_struct, rcu));
153 void release_task(struct task_struct * p)
155 struct task_struct *leader;
156 int zap_leader;
157 repeat:
158 atomic_dec(&p->user->processes);
159 write_lock_irq(&tasklist_lock);
160 ptrace_unlink(p);
161 BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
162 __exit_signal(p);
165 * If we are the last non-leader member of the thread
166 * group, and the leader is zombie, then notify the
167 * group leader's parent process. (if it wants notification.)
169 zap_leader = 0;
170 leader = p->group_leader;
171 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
172 BUG_ON(leader->exit_signal == -1);
173 do_notify_parent(leader, leader->exit_signal);
175 * If we were the last child thread and the leader has
176 * exited already, and the leader's parent ignores SIGCHLD,
177 * then we are the one who should release the leader.
179 * do_notify_parent() will have marked it self-reaping in
180 * that case.
182 zap_leader = (leader->exit_signal == -1);
185 sched_exit(p);
186 write_unlock_irq(&tasklist_lock);
187 proc_flush_task(p);
188 release_thread(p);
189 call_rcu(&p->rcu, delayed_put_task_struct);
191 p = leader;
192 if (unlikely(zap_leader))
193 goto repeat;
197 * This checks not only the pgrp, but falls back on the pid if no
198 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
199 * without this...
201 * The caller must hold rcu lock or the tasklist lock.
203 struct pid *session_of_pgrp(struct pid *pgrp)
205 struct task_struct *p;
206 struct pid *sid = NULL;
208 p = pid_task(pgrp, PIDTYPE_PGID);
209 if (p == NULL)
210 p = pid_task(pgrp, PIDTYPE_PID);
211 if (p != NULL)
212 sid = task_session(p);
214 return sid;
218 * Determine if a process group is "orphaned", according to the POSIX
219 * definition in 2.2.2.52. Orphaned process groups are not to be affected
220 * by terminal-generated stop signals. Newly orphaned process groups are
221 * to receive a SIGHUP and a SIGCONT.
223 * "I ask you, have you ever known what it is to be an orphan?"
225 static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
227 struct task_struct *p;
228 int ret = 1;
230 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
231 if (p == ignored_task
232 || p->exit_state
233 || is_init(p->real_parent))
234 continue;
235 if (task_pgrp(p->real_parent) != pgrp &&
236 task_session(p->real_parent) == task_session(p)) {
237 ret = 0;
238 break;
240 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
241 return ret; /* (sighing) "Often!" */
244 int is_current_pgrp_orphaned(void)
246 int retval;
248 read_lock(&tasklist_lock);
249 retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
250 read_unlock(&tasklist_lock);
252 return retval;
255 static int has_stopped_jobs(struct pid *pgrp)
257 int retval = 0;
258 struct task_struct *p;
260 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
261 if (p->state != TASK_STOPPED)
262 continue;
263 retval = 1;
264 break;
265 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
266 return retval;
270 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
272 * If a kernel thread is launched as a result of a system call, or if
273 * it ever exits, it should generally reparent itself to kthreadd so it
274 * isn't in the way of other processes and is correctly cleaned up on exit.
276 * The various task state such as scheduling policy and priority may have
277 * been inherited from a user process, so we reset them to sane values here.
279 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
281 static void reparent_to_kthreadd(void)
283 write_lock_irq(&tasklist_lock);
285 ptrace_unlink(current);
286 /* Reparent to init */
287 remove_parent(current);
288 current->real_parent = current->parent = kthreadd_task;
289 add_parent(current);
291 /* Set the exit signal to SIGCHLD so we signal init on exit */
292 current->exit_signal = SIGCHLD;
294 if (!has_rt_policy(current) && (task_nice(current) < 0))
295 set_user_nice(current, 0);
296 /* cpus_allowed? */
297 /* rt_priority? */
298 /* signals? */
299 security_task_reparent_to_init(current);
300 memcpy(current->signal->rlim, init_task.signal->rlim,
301 sizeof(current->signal->rlim));
302 atomic_inc(&(INIT_USER->__count));
303 write_unlock_irq(&tasklist_lock);
304 switch_uid(INIT_USER);
307 void __set_special_pids(pid_t session, pid_t pgrp)
309 struct task_struct *curr = current->group_leader;
311 if (process_session(curr) != session) {
312 detach_pid(curr, PIDTYPE_SID);
313 set_signal_session(curr->signal, session);
314 attach_pid(curr, PIDTYPE_SID, find_pid(session));
316 if (process_group(curr) != pgrp) {
317 detach_pid(curr, PIDTYPE_PGID);
318 curr->signal->pgrp = pgrp;
319 attach_pid(curr, PIDTYPE_PGID, find_pid(pgrp));
323 static void set_special_pids(pid_t session, pid_t pgrp)
325 write_lock_irq(&tasklist_lock);
326 __set_special_pids(session, pgrp);
327 write_unlock_irq(&tasklist_lock);
331 * Let kernel threads use this to say that they
332 * allow a certain signal (since daemonize() will
333 * have disabled all of them by default).
335 int allow_signal(int sig)
337 if (!valid_signal(sig) || sig < 1)
338 return -EINVAL;
340 spin_lock_irq(&current->sighand->siglock);
341 sigdelset(&current->blocked, sig);
342 if (!current->mm) {
343 /* Kernel threads handle their own signals.
344 Let the signal code know it'll be handled, so
345 that they don't get converted to SIGKILL or
346 just silently dropped */
347 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
349 recalc_sigpending();
350 spin_unlock_irq(&current->sighand->siglock);
351 return 0;
354 EXPORT_SYMBOL(allow_signal);
356 int disallow_signal(int sig)
358 if (!valid_signal(sig) || sig < 1)
359 return -EINVAL;
361 spin_lock_irq(&current->sighand->siglock);
362 current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
363 recalc_sigpending();
364 spin_unlock_irq(&current->sighand->siglock);
365 return 0;
368 EXPORT_SYMBOL(disallow_signal);
371 * Put all the gunge required to become a kernel thread without
372 * attached user resources in one place where it belongs.
375 void daemonize(const char *name, ...)
377 va_list args;
378 struct fs_struct *fs;
379 sigset_t blocked;
381 va_start(args, name);
382 vsnprintf(current->comm, sizeof(current->comm), name, args);
383 va_end(args);
386 * If we were started as result of loading a module, close all of the
387 * user space pages. We don't need them, and if we didn't close them
388 * they would be locked into memory.
390 exit_mm(current);
392 set_special_pids(1, 1);
393 proc_clear_tty(current);
395 /* Block and flush all signals */
396 sigfillset(&blocked);
397 sigprocmask(SIG_BLOCK, &blocked, NULL);
398 flush_signals(current);
400 /* Become as one with the init task */
402 exit_fs(current); /* current->fs->count--; */
403 fs = init_task.fs;
404 current->fs = fs;
405 atomic_inc(&fs->count);
407 exit_task_namespaces(current);
408 current->nsproxy = init_task.nsproxy;
409 get_task_namespaces(current);
411 exit_files(current);
412 current->files = init_task.files;
413 atomic_inc(&current->files->count);
415 reparent_to_kthreadd();
418 EXPORT_SYMBOL(daemonize);
420 static void close_files(struct files_struct * files)
422 int i, j;
423 struct fdtable *fdt;
425 j = 0;
428 * It is safe to dereference the fd table without RCU or
429 * ->file_lock because this is the last reference to the
430 * files structure.
432 fdt = files_fdtable(files);
433 for (;;) {
434 unsigned long set;
435 i = j * __NFDBITS;
436 if (i >= fdt->max_fds)
437 break;
438 set = fdt->open_fds->fds_bits[j++];
439 while (set) {
440 if (set & 1) {
441 struct file * file = xchg(&fdt->fd[i], NULL);
442 if (file) {
443 filp_close(file, files);
444 cond_resched();
447 i++;
448 set >>= 1;
453 struct files_struct *get_files_struct(struct task_struct *task)
455 struct files_struct *files;
457 task_lock(task);
458 files = task->files;
459 if (files)
460 atomic_inc(&files->count);
461 task_unlock(task);
463 return files;
466 void fastcall put_files_struct(struct files_struct *files)
468 struct fdtable *fdt;
470 if (atomic_dec_and_test(&files->count)) {
471 close_files(files);
473 * Free the fd and fdset arrays if we expanded them.
474 * If the fdtable was embedded, pass files for freeing
475 * at the end of the RCU grace period. Otherwise,
476 * you can free files immediately.
478 fdt = files_fdtable(files);
479 if (fdt != &files->fdtab)
480 kmem_cache_free(files_cachep, files);
481 free_fdtable(fdt);
485 EXPORT_SYMBOL(put_files_struct);
487 void reset_files_struct(struct task_struct *tsk, struct files_struct *files)
489 struct files_struct *old;
491 old = tsk->files;
492 task_lock(tsk);
493 tsk->files = files;
494 task_unlock(tsk);
495 put_files_struct(old);
497 EXPORT_SYMBOL(reset_files_struct);
499 static inline void __exit_files(struct task_struct *tsk)
501 struct files_struct * files = tsk->files;
503 if (files) {
504 task_lock(tsk);
505 tsk->files = NULL;
506 task_unlock(tsk);
507 put_files_struct(files);
511 void exit_files(struct task_struct *tsk)
513 __exit_files(tsk);
516 static inline void __put_fs_struct(struct fs_struct *fs)
518 /* No need to hold fs->lock if we are killing it */
519 if (atomic_dec_and_test(&fs->count)) {
520 dput(fs->root);
521 mntput(fs->rootmnt);
522 dput(fs->pwd);
523 mntput(fs->pwdmnt);
524 if (fs->altroot) {
525 dput(fs->altroot);
526 mntput(fs->altrootmnt);
528 kmem_cache_free(fs_cachep, fs);
532 void put_fs_struct(struct fs_struct *fs)
534 __put_fs_struct(fs);
537 static inline void __exit_fs(struct task_struct *tsk)
539 struct fs_struct * fs = tsk->fs;
541 if (fs) {
542 task_lock(tsk);
543 tsk->fs = NULL;
544 task_unlock(tsk);
545 __put_fs_struct(fs);
549 void exit_fs(struct task_struct *tsk)
551 __exit_fs(tsk);
554 EXPORT_SYMBOL_GPL(exit_fs);
557 * Turn us into a lazy TLB process if we
558 * aren't already..
560 static void exit_mm(struct task_struct * tsk)
562 struct mm_struct *mm = tsk->mm;
564 mm_release(tsk, mm);
565 if (!mm)
566 return;
568 * Serialize with any possible pending coredump.
569 * We must hold mmap_sem around checking core_waiters
570 * and clearing tsk->mm. The core-inducing thread
571 * will increment core_waiters for each thread in the
572 * group with ->mm != NULL.
574 down_read(&mm->mmap_sem);
575 if (mm->core_waiters) {
576 up_read(&mm->mmap_sem);
577 down_write(&mm->mmap_sem);
578 if (!--mm->core_waiters)
579 complete(mm->core_startup_done);
580 up_write(&mm->mmap_sem);
582 wait_for_completion(&mm->core_done);
583 down_read(&mm->mmap_sem);
585 atomic_inc(&mm->mm_count);
586 BUG_ON(mm != tsk->active_mm);
587 /* more a memory barrier than a real lock */
588 task_lock(tsk);
589 tsk->mm = NULL;
590 up_read(&mm->mmap_sem);
591 enter_lazy_tlb(mm, current);
592 task_unlock(tsk);
593 mmput(mm);
596 static inline void
597 choose_new_parent(struct task_struct *p, struct task_struct *reaper)
600 * Make sure we're not reparenting to ourselves and that
601 * the parent is not a zombie.
603 BUG_ON(p == reaper || reaper->exit_state);
604 p->real_parent = reaper;
607 static void
608 reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
610 if (p->pdeath_signal)
611 /* We already hold the tasklist_lock here. */
612 group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
614 /* Move the child from its dying parent to the new one. */
615 if (unlikely(traced)) {
616 /* Preserve ptrace links if someone else is tracing this child. */
617 list_del_init(&p->ptrace_list);
618 if (p->parent != p->real_parent)
619 list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
620 } else {
621 /* If this child is being traced, then we're the one tracing it
622 * anyway, so let go of it.
624 p->ptrace = 0;
625 remove_parent(p);
626 p->parent = p->real_parent;
627 add_parent(p);
629 if (p->state == TASK_TRACED) {
631 * If it was at a trace stop, turn it into
632 * a normal stop since it's no longer being
633 * traced.
635 ptrace_untrace(p);
639 /* If this is a threaded reparent there is no need to
640 * notify anyone anything has happened.
642 if (p->real_parent->group_leader == father->group_leader)
643 return;
645 /* We don't want people slaying init. */
646 if (p->exit_signal != -1)
647 p->exit_signal = SIGCHLD;
649 /* If we'd notified the old parent about this child's death,
650 * also notify the new parent.
652 if (!traced && p->exit_state == EXIT_ZOMBIE &&
653 p->exit_signal != -1 && thread_group_empty(p))
654 do_notify_parent(p, p->exit_signal);
657 * process group orphan check
658 * Case ii: Our child is in a different pgrp
659 * than we are, and it was the only connection
660 * outside, so the child pgrp is now orphaned.
662 if ((task_pgrp(p) != task_pgrp(father)) &&
663 (task_session(p) == task_session(father))) {
664 struct pid *pgrp = task_pgrp(p);
666 if (will_become_orphaned_pgrp(pgrp, NULL) &&
667 has_stopped_jobs(pgrp)) {
668 __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
669 __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
675 * When we die, we re-parent all our children.
676 * Try to give them to another thread in our thread
677 * group, and if no such member exists, give it to
678 * the child reaper process (ie "init") in our pid
679 * space.
681 static void
682 forget_original_parent(struct task_struct *father, struct list_head *to_release)
684 struct task_struct *p, *reaper = father;
685 struct list_head *_p, *_n;
687 do {
688 reaper = next_thread(reaper);
689 if (reaper == father) {
690 reaper = child_reaper(father);
691 break;
693 } while (reaper->exit_state);
696 * There are only two places where our children can be:
698 * - in our child list
699 * - in our ptraced child list
701 * Search them and reparent children.
703 list_for_each_safe(_p, _n, &father->children) {
704 int ptrace;
705 p = list_entry(_p, struct task_struct, sibling);
707 ptrace = p->ptrace;
709 /* if father isn't the real parent, then ptrace must be enabled */
710 BUG_ON(father != p->real_parent && !ptrace);
712 if (father == p->real_parent) {
713 /* reparent with a reaper, real father it's us */
714 choose_new_parent(p, reaper);
715 reparent_thread(p, father, 0);
716 } else {
717 /* reparent ptraced task to its real parent */
718 __ptrace_unlink (p);
719 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
720 thread_group_empty(p))
721 do_notify_parent(p, p->exit_signal);
725 * if the ptraced child is a zombie with exit_signal == -1
726 * we must collect it before we exit, or it will remain
727 * zombie forever since we prevented it from self-reap itself
728 * while it was being traced by us, to be able to see it in wait4.
730 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
731 list_add(&p->ptrace_list, to_release);
733 list_for_each_safe(_p, _n, &father->ptrace_children) {
734 p = list_entry(_p, struct task_struct, ptrace_list);
735 choose_new_parent(p, reaper);
736 reparent_thread(p, father, 1);
741 * Send signals to all our closest relatives so that they know
742 * to properly mourn us..
744 static void exit_notify(struct task_struct *tsk)
746 int state;
747 struct task_struct *t;
748 struct list_head ptrace_dead, *_p, *_n;
749 struct pid *pgrp;
751 if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
752 && !thread_group_empty(tsk)) {
754 * This occurs when there was a race between our exit
755 * syscall and a group signal choosing us as the one to
756 * wake up. It could be that we are the only thread
757 * alerted to check for pending signals, but another thread
758 * should be woken now to take the signal since we will not.
759 * Now we'll wake all the threads in the group just to make
760 * sure someone gets all the pending signals.
762 read_lock(&tasklist_lock);
763 spin_lock_irq(&tsk->sighand->siglock);
764 for (t = next_thread(tsk); t != tsk; t = next_thread(t))
765 if (!signal_pending(t) && !(t->flags & PF_EXITING))
766 recalc_sigpending_and_wake(t);
767 spin_unlock_irq(&tsk->sighand->siglock);
768 read_unlock(&tasklist_lock);
771 write_lock_irq(&tasklist_lock);
774 * This does two things:
776 * A. Make init inherit all the child processes
777 * B. Check to see if any process groups have become orphaned
778 * as a result of our exiting, and if they have any stopped
779 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
782 INIT_LIST_HEAD(&ptrace_dead);
783 forget_original_parent(tsk, &ptrace_dead);
784 BUG_ON(!list_empty(&tsk->children));
785 BUG_ON(!list_empty(&tsk->ptrace_children));
788 * Check to see if any process groups have become orphaned
789 * as a result of our exiting, and if they have any stopped
790 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
792 * Case i: Our father is in a different pgrp than we are
793 * and we were the only connection outside, so our pgrp
794 * is about to become orphaned.
797 t = tsk->real_parent;
799 pgrp = task_pgrp(tsk);
800 if ((task_pgrp(t) != pgrp) &&
801 (task_session(t) == task_session(tsk)) &&
802 will_become_orphaned_pgrp(pgrp, tsk) &&
803 has_stopped_jobs(pgrp)) {
804 __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
805 __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
808 /* Let father know we died
810 * Thread signals are configurable, but you aren't going to use
811 * that to send signals to arbitary processes.
812 * That stops right now.
814 * If the parent exec id doesn't match the exec id we saved
815 * when we started then we know the parent has changed security
816 * domain.
818 * If our self_exec id doesn't match our parent_exec_id then
819 * we have changed execution domain as these two values started
820 * the same after a fork.
824 if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
825 ( tsk->parent_exec_id != t->self_exec_id ||
826 tsk->self_exec_id != tsk->parent_exec_id)
827 && !capable(CAP_KILL))
828 tsk->exit_signal = SIGCHLD;
831 /* If something other than our normal parent is ptracing us, then
832 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
833 * only has special meaning to our real parent.
835 if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
836 int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
837 do_notify_parent(tsk, signal);
838 } else if (tsk->ptrace) {
839 do_notify_parent(tsk, SIGCHLD);
842 state = EXIT_ZOMBIE;
843 if (tsk->exit_signal == -1 &&
844 (likely(tsk->ptrace == 0) ||
845 unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT)))
846 state = EXIT_DEAD;
847 tsk->exit_state = state;
849 write_unlock_irq(&tasklist_lock);
851 list_for_each_safe(_p, _n, &ptrace_dead) {
852 list_del_init(_p);
853 t = list_entry(_p, struct task_struct, ptrace_list);
854 release_task(t);
857 /* If the process is dead, release it - nobody will wait for it */
858 if (state == EXIT_DEAD)
859 release_task(tsk);
862 fastcall NORET_TYPE void do_exit(long code)
864 struct task_struct *tsk = current;
865 int group_dead;
867 profile_task_exit(tsk);
869 WARN_ON(atomic_read(&tsk->fs_excl));
871 if (unlikely(in_interrupt()))
872 panic("Aiee, killing interrupt handler!");
873 if (unlikely(!tsk->pid))
874 panic("Attempted to kill the idle task!");
875 if (unlikely(tsk == child_reaper(tsk))) {
876 if (tsk->nsproxy->pid_ns != &init_pid_ns)
877 tsk->nsproxy->pid_ns->child_reaper = init_pid_ns.child_reaper;
878 else
879 panic("Attempted to kill init!");
883 if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
884 current->ptrace_message = code;
885 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
889 * We're taking recursive faults here in do_exit. Safest is to just
890 * leave this task alone and wait for reboot.
892 if (unlikely(tsk->flags & PF_EXITING)) {
893 printk(KERN_ALERT
894 "Fixing recursive fault but reboot is needed!\n");
896 * We can do this unlocked here. The futex code uses
897 * this flag just to verify whether the pi state
898 * cleanup has been done or not. In the worst case it
899 * loops once more. We pretend that the cleanup was
900 * done as there is no way to return. Either the
901 * OWNER_DIED bit is set by now or we push the blocked
902 * task into the wait for ever nirwana as well.
904 tsk->flags |= PF_EXITPIDONE;
905 if (tsk->io_context)
906 exit_io_context();
907 set_current_state(TASK_UNINTERRUPTIBLE);
908 schedule();
912 * tsk->flags are checked in the futex code to protect against
913 * an exiting task cleaning up the robust pi futexes.
915 spin_lock_irq(&tsk->pi_lock);
916 tsk->flags |= PF_EXITING;
917 spin_unlock_irq(&tsk->pi_lock);
919 if (unlikely(in_atomic()))
920 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
921 current->comm, current->pid,
922 preempt_count());
924 acct_update_integrals(tsk);
925 if (tsk->mm) {
926 update_hiwater_rss(tsk->mm);
927 update_hiwater_vm(tsk->mm);
929 group_dead = atomic_dec_and_test(&tsk->signal->live);
930 if (group_dead) {
931 hrtimer_cancel(&tsk->signal->real_timer);
932 exit_itimers(tsk->signal);
934 acct_collect(code, group_dead);
935 if (unlikely(tsk->robust_list))
936 exit_robust_list(tsk);
937 #if defined(CONFIG_FUTEX) && defined(CONFIG_COMPAT)
938 if (unlikely(tsk->compat_robust_list))
939 compat_exit_robust_list(tsk);
940 #endif
941 if (unlikely(tsk->audit_context))
942 audit_free(tsk);
944 taskstats_exit(tsk, group_dead);
946 exit_mm(tsk);
948 if (group_dead)
949 acct_process();
950 exit_sem(tsk);
951 __exit_files(tsk);
952 __exit_fs(tsk);
953 exit_thread();
954 cpuset_exit(tsk);
955 exit_keys(tsk);
957 if (group_dead && tsk->signal->leader)
958 disassociate_ctty(1);
960 module_put(task_thread_info(tsk)->exec_domain->module);
961 if (tsk->binfmt)
962 module_put(tsk->binfmt->module);
964 tsk->exit_code = code;
965 proc_exit_connector(tsk);
966 exit_task_namespaces(tsk);
967 exit_notify(tsk);
968 #ifdef CONFIG_NUMA
969 mpol_free(tsk->mempolicy);
970 tsk->mempolicy = NULL;
971 #endif
973 * This must happen late, after the PID is not
974 * hashed anymore:
976 if (unlikely(!list_empty(&tsk->pi_state_list)))
977 exit_pi_state_list(tsk);
978 if (unlikely(current->pi_state_cache))
979 kfree(current->pi_state_cache);
981 * Make sure we are holding no locks:
983 debug_check_no_locks_held(tsk);
985 * We can do this unlocked here. The futex code uses this flag
986 * just to verify whether the pi state cleanup has been done
987 * or not. In the worst case it loops once more.
989 tsk->flags |= PF_EXITPIDONE;
991 if (tsk->io_context)
992 exit_io_context();
994 if (tsk->splice_pipe)
995 __free_pipe_info(tsk->splice_pipe);
997 preempt_disable();
998 /* causes final put_task_struct in finish_task_switch(). */
999 tsk->state = TASK_DEAD;
1001 schedule();
1002 BUG();
1003 /* Avoid "noreturn function does return". */
1004 for (;;)
1005 cpu_relax(); /* For when BUG is null */
1008 EXPORT_SYMBOL_GPL(do_exit);
1010 NORET_TYPE void complete_and_exit(struct completion *comp, long code)
1012 if (comp)
1013 complete(comp);
1015 do_exit(code);
1018 EXPORT_SYMBOL(complete_and_exit);
1020 asmlinkage long sys_exit(int error_code)
1022 do_exit((error_code&0xff)<<8);
1026 * Take down every thread in the group. This is called by fatal signals
1027 * as well as by sys_exit_group (below).
1029 NORET_TYPE void
1030 do_group_exit(int exit_code)
1032 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
1034 if (current->signal->flags & SIGNAL_GROUP_EXIT)
1035 exit_code = current->signal->group_exit_code;
1036 else if (!thread_group_empty(current)) {
1037 struct signal_struct *const sig = current->signal;
1038 struct sighand_struct *const sighand = current->sighand;
1039 spin_lock_irq(&sighand->siglock);
1040 if (sig->flags & SIGNAL_GROUP_EXIT)
1041 /* Another thread got here before we took the lock. */
1042 exit_code = sig->group_exit_code;
1043 else {
1044 sig->group_exit_code = exit_code;
1045 zap_other_threads(current);
1047 spin_unlock_irq(&sighand->siglock);
1050 do_exit(exit_code);
1051 /* NOTREACHED */
1055 * this kills every thread in the thread group. Note that any externally
1056 * wait4()-ing process will get the correct exit code - even if this
1057 * thread is not the thread group leader.
1059 asmlinkage void sys_exit_group(int error_code)
1061 do_group_exit((error_code & 0xff) << 8);
1064 static int eligible_child(pid_t pid, int options, struct task_struct *p)
1066 int err;
1068 if (pid > 0) {
1069 if (p->pid != pid)
1070 return 0;
1071 } else if (!pid) {
1072 if (process_group(p) != process_group(current))
1073 return 0;
1074 } else if (pid != -1) {
1075 if (process_group(p) != -pid)
1076 return 0;
1080 * Do not consider detached threads that are
1081 * not ptraced:
1083 if (p->exit_signal == -1 && !p->ptrace)
1084 return 0;
1086 /* Wait for all children (clone and not) if __WALL is set;
1087 * otherwise, wait for clone children *only* if __WCLONE is
1088 * set; otherwise, wait for non-clone children *only*. (Note:
1089 * A "clone" child here is one that reports to its parent
1090 * using a signal other than SIGCHLD.) */
1091 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
1092 && !(options & __WALL))
1093 return 0;
1095 * Do not consider thread group leaders that are
1096 * in a non-empty thread group:
1098 if (delay_group_leader(p))
1099 return 2;
1101 err = security_task_wait(p);
1102 if (err)
1103 return err;
1105 return 1;
1108 static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
1109 int why, int status,
1110 struct siginfo __user *infop,
1111 struct rusage __user *rusagep)
1113 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
1115 put_task_struct(p);
1116 if (!retval)
1117 retval = put_user(SIGCHLD, &infop->si_signo);
1118 if (!retval)
1119 retval = put_user(0, &infop->si_errno);
1120 if (!retval)
1121 retval = put_user((short)why, &infop->si_code);
1122 if (!retval)
1123 retval = put_user(pid, &infop->si_pid);
1124 if (!retval)
1125 retval = put_user(uid, &infop->si_uid);
1126 if (!retval)
1127 retval = put_user(status, &infop->si_status);
1128 if (!retval)
1129 retval = pid;
1130 return retval;
1134 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1135 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1136 * the lock and this task is uninteresting. If we return nonzero, we have
1137 * released the lock and the system call should return.
1139 static int wait_task_zombie(struct task_struct *p, int noreap,
1140 struct siginfo __user *infop,
1141 int __user *stat_addr, struct rusage __user *ru)
1143 unsigned long state;
1144 int retval;
1145 int status;
1147 if (unlikely(noreap)) {
1148 pid_t pid = p->pid;
1149 uid_t uid = p->uid;
1150 int exit_code = p->exit_code;
1151 int why, status;
1153 if (unlikely(p->exit_state != EXIT_ZOMBIE))
1154 return 0;
1155 if (unlikely(p->exit_signal == -1 && p->ptrace == 0))
1156 return 0;
1157 get_task_struct(p);
1158 read_unlock(&tasklist_lock);
1159 if ((exit_code & 0x7f) == 0) {
1160 why = CLD_EXITED;
1161 status = exit_code >> 8;
1162 } else {
1163 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1164 status = exit_code & 0x7f;
1166 return wait_noreap_copyout(p, pid, uid, why,
1167 status, infop, ru);
1171 * Try to move the task's state to DEAD
1172 * only one thread is allowed to do this:
1174 state = xchg(&p->exit_state, EXIT_DEAD);
1175 if (state != EXIT_ZOMBIE) {
1176 BUG_ON(state != EXIT_DEAD);
1177 return 0;
1179 if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) {
1181 * This can only happen in a race with a ptraced thread
1182 * dying on another processor.
1184 return 0;
1187 if (likely(p->real_parent == p->parent) && likely(p->signal)) {
1188 struct signal_struct *psig;
1189 struct signal_struct *sig;
1192 * The resource counters for the group leader are in its
1193 * own task_struct. Those for dead threads in the group
1194 * are in its signal_struct, as are those for the child
1195 * processes it has previously reaped. All these
1196 * accumulate in the parent's signal_struct c* fields.
1198 * We don't bother to take a lock here to protect these
1199 * p->signal fields, because they are only touched by
1200 * __exit_signal, which runs with tasklist_lock
1201 * write-locked anyway, and so is excluded here. We do
1202 * need to protect the access to p->parent->signal fields,
1203 * as other threads in the parent group can be right
1204 * here reaping other children at the same time.
1206 spin_lock_irq(&p->parent->sighand->siglock);
1207 psig = p->parent->signal;
1208 sig = p->signal;
1209 psig->cutime =
1210 cputime_add(psig->cutime,
1211 cputime_add(p->utime,
1212 cputime_add(sig->utime,
1213 sig->cutime)));
1214 psig->cstime =
1215 cputime_add(psig->cstime,
1216 cputime_add(p->stime,
1217 cputime_add(sig->stime,
1218 sig->cstime)));
1219 psig->cmin_flt +=
1220 p->min_flt + sig->min_flt + sig->cmin_flt;
1221 psig->cmaj_flt +=
1222 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1223 psig->cnvcsw +=
1224 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1225 psig->cnivcsw +=
1226 p->nivcsw + sig->nivcsw + sig->cnivcsw;
1227 psig->cinblock +=
1228 task_io_get_inblock(p) +
1229 sig->inblock + sig->cinblock;
1230 psig->coublock +=
1231 task_io_get_oublock(p) +
1232 sig->oublock + sig->coublock;
1233 spin_unlock_irq(&p->parent->sighand->siglock);
1237 * Now we are sure this task is interesting, and no other
1238 * thread can reap it because we set its state to EXIT_DEAD.
1240 read_unlock(&tasklist_lock);
1242 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1243 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1244 ? p->signal->group_exit_code : p->exit_code;
1245 if (!retval && stat_addr)
1246 retval = put_user(status, stat_addr);
1247 if (!retval && infop)
1248 retval = put_user(SIGCHLD, &infop->si_signo);
1249 if (!retval && infop)
1250 retval = put_user(0, &infop->si_errno);
1251 if (!retval && infop) {
1252 int why;
1254 if ((status & 0x7f) == 0) {
1255 why = CLD_EXITED;
1256 status >>= 8;
1257 } else {
1258 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1259 status &= 0x7f;
1261 retval = put_user((short)why, &infop->si_code);
1262 if (!retval)
1263 retval = put_user(status, &infop->si_status);
1265 if (!retval && infop)
1266 retval = put_user(p->pid, &infop->si_pid);
1267 if (!retval && infop)
1268 retval = put_user(p->uid, &infop->si_uid);
1269 if (retval) {
1270 // TODO: is this safe?
1271 p->exit_state = EXIT_ZOMBIE;
1272 return retval;
1274 retval = p->pid;
1275 if (p->real_parent != p->parent) {
1276 write_lock_irq(&tasklist_lock);
1277 /* Double-check with lock held. */
1278 if (p->real_parent != p->parent) {
1279 __ptrace_unlink(p);
1280 // TODO: is this safe?
1281 p->exit_state = EXIT_ZOMBIE;
1283 * If this is not a detached task, notify the parent.
1284 * If it's still not detached after that, don't release
1285 * it now.
1287 if (p->exit_signal != -1) {
1288 do_notify_parent(p, p->exit_signal);
1289 if (p->exit_signal != -1)
1290 p = NULL;
1293 write_unlock_irq(&tasklist_lock);
1295 if (p != NULL)
1296 release_task(p);
1297 BUG_ON(!retval);
1298 return retval;
1302 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1303 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1304 * the lock and this task is uninteresting. If we return nonzero, we have
1305 * released the lock and the system call should return.
1307 static int wait_task_stopped(struct task_struct *p, int delayed_group_leader,
1308 int noreap, struct siginfo __user *infop,
1309 int __user *stat_addr, struct rusage __user *ru)
1311 int retval, exit_code;
1313 if (!p->exit_code)
1314 return 0;
1315 if (delayed_group_leader && !(p->ptrace & PT_PTRACED) &&
1316 p->signal && p->signal->group_stop_count > 0)
1318 * A group stop is in progress and this is the group leader.
1319 * We won't report until all threads have stopped.
1321 return 0;
1324 * Now we are pretty sure this task is interesting.
1325 * Make sure it doesn't get reaped out from under us while we
1326 * give up the lock and then examine it below. We don't want to
1327 * keep holding onto the tasklist_lock while we call getrusage and
1328 * possibly take page faults for user memory.
1330 get_task_struct(p);
1331 read_unlock(&tasklist_lock);
1333 if (unlikely(noreap)) {
1334 pid_t pid = p->pid;
1335 uid_t uid = p->uid;
1336 int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
1338 exit_code = p->exit_code;
1339 if (unlikely(!exit_code) || unlikely(p->exit_state))
1340 goto bail_ref;
1341 return wait_noreap_copyout(p, pid, uid,
1342 why, exit_code,
1343 infop, ru);
1346 write_lock_irq(&tasklist_lock);
1349 * This uses xchg to be atomic with the thread resuming and setting
1350 * it. It must also be done with the write lock held to prevent a
1351 * race with the EXIT_ZOMBIE case.
1353 exit_code = xchg(&p->exit_code, 0);
1354 if (unlikely(p->exit_state)) {
1356 * The task resumed and then died. Let the next iteration
1357 * catch it in EXIT_ZOMBIE. Note that exit_code might
1358 * already be zero here if it resumed and did _exit(0).
1359 * The task itself is dead and won't touch exit_code again;
1360 * other processors in this function are locked out.
1362 p->exit_code = exit_code;
1363 exit_code = 0;
1365 if (unlikely(exit_code == 0)) {
1367 * Another thread in this function got to it first, or it
1368 * resumed, or it resumed and then died.
1370 write_unlock_irq(&tasklist_lock);
1371 bail_ref:
1372 put_task_struct(p);
1374 * We are returning to the wait loop without having successfully
1375 * removed the process and having released the lock. We cannot
1376 * continue, since the "p" task pointer is potentially stale.
1378 * Return -EAGAIN, and do_wait() will restart the loop from the
1379 * beginning. Do _not_ re-acquire the lock.
1381 return -EAGAIN;
1384 /* move to end of parent's list to avoid starvation */
1385 remove_parent(p);
1386 add_parent(p);
1388 write_unlock_irq(&tasklist_lock);
1390 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1391 if (!retval && stat_addr)
1392 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1393 if (!retval && infop)
1394 retval = put_user(SIGCHLD, &infop->si_signo);
1395 if (!retval && infop)
1396 retval = put_user(0, &infop->si_errno);
1397 if (!retval && infop)
1398 retval = put_user((short)((p->ptrace & PT_PTRACED)
1399 ? CLD_TRAPPED : CLD_STOPPED),
1400 &infop->si_code);
1401 if (!retval && infop)
1402 retval = put_user(exit_code, &infop->si_status);
1403 if (!retval && infop)
1404 retval = put_user(p->pid, &infop->si_pid);
1405 if (!retval && infop)
1406 retval = put_user(p->uid, &infop->si_uid);
1407 if (!retval)
1408 retval = p->pid;
1409 put_task_struct(p);
1411 BUG_ON(!retval);
1412 return retval;
1416 * Handle do_wait work for one task in a live, non-stopped state.
1417 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1418 * the lock and this task is uninteresting. If we return nonzero, we have
1419 * released the lock and the system call should return.
1421 static int wait_task_continued(struct task_struct *p, int noreap,
1422 struct siginfo __user *infop,
1423 int __user *stat_addr, struct rusage __user *ru)
1425 int retval;
1426 pid_t pid;
1427 uid_t uid;
1429 if (unlikely(!p->signal))
1430 return 0;
1432 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1433 return 0;
1435 spin_lock_irq(&p->sighand->siglock);
1436 /* Re-check with the lock held. */
1437 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1438 spin_unlock_irq(&p->sighand->siglock);
1439 return 0;
1441 if (!noreap)
1442 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1443 spin_unlock_irq(&p->sighand->siglock);
1445 pid = p->pid;
1446 uid = p->uid;
1447 get_task_struct(p);
1448 read_unlock(&tasklist_lock);
1450 if (!infop) {
1451 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1452 put_task_struct(p);
1453 if (!retval && stat_addr)
1454 retval = put_user(0xffff, stat_addr);
1455 if (!retval)
1456 retval = p->pid;
1457 } else {
1458 retval = wait_noreap_copyout(p, pid, uid,
1459 CLD_CONTINUED, SIGCONT,
1460 infop, ru);
1461 BUG_ON(retval == 0);
1464 return retval;
1468 static inline int my_ptrace_child(struct task_struct *p)
1470 if (!(p->ptrace & PT_PTRACED))
1471 return 0;
1472 if (!(p->ptrace & PT_ATTACHED))
1473 return 1;
1475 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1476 * we are the attacher. If we are the real parent, this is a race
1477 * inside ptrace_attach. It is waiting for the tasklist_lock,
1478 * which we have to switch the parent links, but has already set
1479 * the flags in p->ptrace.
1481 return (p->parent != p->real_parent);
1484 static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
1485 int __user *stat_addr, struct rusage __user *ru)
1487 DECLARE_WAITQUEUE(wait, current);
1488 struct task_struct *tsk;
1489 int flag, retval;
1490 int allowed, denied;
1492 add_wait_queue(&current->signal->wait_chldexit,&wait);
1493 repeat:
1495 * We will set this flag if we see any child that might later
1496 * match our criteria, even if we are not able to reap it yet.
1498 flag = 0;
1499 allowed = denied = 0;
1500 current->state = TASK_INTERRUPTIBLE;
1501 read_lock(&tasklist_lock);
1502 tsk = current;
1503 do {
1504 struct task_struct *p;
1505 struct list_head *_p;
1506 int ret;
1508 list_for_each(_p,&tsk->children) {
1509 p = list_entry(_p, struct task_struct, sibling);
1511 ret = eligible_child(pid, options, p);
1512 if (!ret)
1513 continue;
1515 if (unlikely(ret < 0)) {
1516 denied = ret;
1517 continue;
1519 allowed = 1;
1521 switch (p->state) {
1522 case TASK_TRACED:
1524 * When we hit the race with PTRACE_ATTACH,
1525 * we will not report this child. But the
1526 * race means it has not yet been moved to
1527 * our ptrace_children list, so we need to
1528 * set the flag here to avoid a spurious ECHILD
1529 * when the race happens with the only child.
1531 flag = 1;
1532 if (!my_ptrace_child(p))
1533 continue;
1534 /*FALLTHROUGH*/
1535 case TASK_STOPPED:
1537 * It's stopped now, so it might later
1538 * continue, exit, or stop again.
1540 flag = 1;
1541 if (!(options & WUNTRACED) &&
1542 !my_ptrace_child(p))
1543 continue;
1544 retval = wait_task_stopped(p, ret == 2,
1545 (options & WNOWAIT),
1546 infop,
1547 stat_addr, ru);
1548 if (retval == -EAGAIN)
1549 goto repeat;
1550 if (retval != 0) /* He released the lock. */
1551 goto end;
1552 break;
1553 default:
1554 // case EXIT_DEAD:
1555 if (p->exit_state == EXIT_DEAD)
1556 continue;
1557 // case EXIT_ZOMBIE:
1558 if (p->exit_state == EXIT_ZOMBIE) {
1560 * Eligible but we cannot release
1561 * it yet:
1563 if (ret == 2)
1564 goto check_continued;
1565 if (!likely(options & WEXITED))
1566 continue;
1567 retval = wait_task_zombie(
1568 p, (options & WNOWAIT),
1569 infop, stat_addr, ru);
1570 /* He released the lock. */
1571 if (retval != 0)
1572 goto end;
1573 break;
1575 check_continued:
1577 * It's running now, so it might later
1578 * exit, stop, or stop and then continue.
1580 flag = 1;
1581 if (!unlikely(options & WCONTINUED))
1582 continue;
1583 retval = wait_task_continued(
1584 p, (options & WNOWAIT),
1585 infop, stat_addr, ru);
1586 if (retval != 0) /* He released the lock. */
1587 goto end;
1588 break;
1591 if (!flag) {
1592 list_for_each(_p, &tsk->ptrace_children) {
1593 p = list_entry(_p, struct task_struct,
1594 ptrace_list);
1595 if (!eligible_child(pid, options, p))
1596 continue;
1597 flag = 1;
1598 break;
1601 if (options & __WNOTHREAD)
1602 break;
1603 tsk = next_thread(tsk);
1604 BUG_ON(tsk->signal != current->signal);
1605 } while (tsk != current);
1607 read_unlock(&tasklist_lock);
1608 if (flag) {
1609 retval = 0;
1610 if (options & WNOHANG)
1611 goto end;
1612 retval = -ERESTARTSYS;
1613 if (signal_pending(current))
1614 goto end;
1615 schedule();
1616 goto repeat;
1618 retval = -ECHILD;
1619 if (unlikely(denied) && !allowed)
1620 retval = denied;
1621 end:
1622 current->state = TASK_RUNNING;
1623 remove_wait_queue(&current->signal->wait_chldexit,&wait);
1624 if (infop) {
1625 if (retval > 0)
1626 retval = 0;
1627 else {
1629 * For a WNOHANG return, clear out all the fields
1630 * we would set so the user can easily tell the
1631 * difference.
1633 if (!retval)
1634 retval = put_user(0, &infop->si_signo);
1635 if (!retval)
1636 retval = put_user(0, &infop->si_errno);
1637 if (!retval)
1638 retval = put_user(0, &infop->si_code);
1639 if (!retval)
1640 retval = put_user(0, &infop->si_pid);
1641 if (!retval)
1642 retval = put_user(0, &infop->si_uid);
1643 if (!retval)
1644 retval = put_user(0, &infop->si_status);
1647 return retval;
1650 asmlinkage long sys_waitid(int which, pid_t pid,
1651 struct siginfo __user *infop, int options,
1652 struct rusage __user *ru)
1654 long ret;
1656 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1657 return -EINVAL;
1658 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1659 return -EINVAL;
1661 switch (which) {
1662 case P_ALL:
1663 pid = -1;
1664 break;
1665 case P_PID:
1666 if (pid <= 0)
1667 return -EINVAL;
1668 break;
1669 case P_PGID:
1670 if (pid <= 0)
1671 return -EINVAL;
1672 pid = -pid;
1673 break;
1674 default:
1675 return -EINVAL;
1678 ret = do_wait(pid, options, infop, NULL, ru);
1680 /* avoid REGPARM breakage on x86: */
1681 prevent_tail_call(ret);
1682 return ret;
1685 asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
1686 int options, struct rusage __user *ru)
1688 long ret;
1690 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1691 __WNOTHREAD|__WCLONE|__WALL))
1692 return -EINVAL;
1693 ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru);
1695 /* avoid REGPARM breakage on x86: */
1696 prevent_tail_call(ret);
1697 return ret;
1700 #ifdef __ARCH_WANT_SYS_WAITPID
1703 * sys_waitpid() remains for compatibility. waitpid() should be
1704 * implemented by calling sys_wait4() from libc.a.
1706 asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
1708 return sys_wait4(pid, stat_addr, options, NULL);
1711 #endif