Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
[linux-2.6/verdex.git] / kernel / exit.c
blobcd20bf07e9e3b7bb2260c4a5939642c9e4bcb0a5
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/mount.h>
28 #include <linux/proc_fs.h>
29 #include <linux/kthread.h>
30 #include <linux/mempolicy.h>
31 #include <linux/taskstats_kern.h>
32 #include <linux/delayacct.h>
33 #include <linux/freezer.h>
34 #include <linux/cgroup.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 static void exit_mm(struct task_struct * tsk);
55 static void __unhash_process(struct task_struct *p)
57 nr_threads--;
58 detach_pid(p, PIDTYPE_PID);
59 if (thread_group_leader(p)) {
60 detach_pid(p, PIDTYPE_PGID);
61 detach_pid(p, PIDTYPE_SID);
63 list_del_rcu(&p->tasks);
64 __get_cpu_var(process_counts)--;
66 list_del_rcu(&p->thread_group);
67 remove_parent(p);
71 * This function expects the tasklist_lock write-locked.
73 static void __exit_signal(struct task_struct *tsk)
75 struct signal_struct *sig = tsk->signal;
76 struct sighand_struct *sighand;
78 BUG_ON(!sig);
79 BUG_ON(!atomic_read(&sig->count));
81 rcu_read_lock();
82 sighand = rcu_dereference(tsk->sighand);
83 spin_lock(&sighand->siglock);
85 posix_cpu_timers_exit(tsk);
86 if (atomic_dec_and_test(&sig->count))
87 posix_cpu_timers_exit_group(tsk);
88 else {
90 * If there is any task waiting for the group exit
91 * then notify it:
93 if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count)
94 wake_up_process(sig->group_exit_task);
96 if (tsk == sig->curr_target)
97 sig->curr_target = next_thread(tsk);
99 * Accumulate here the counters for all threads but the
100 * group leader as they die, so they can be added into
101 * the process-wide totals when those are taken.
102 * The group leader stays around as a zombie as long
103 * as there are other threads. When it gets reaped,
104 * the exit.c code will add its counts into these totals.
105 * We won't ever get here for the group leader, since it
106 * will have been the last reference on the signal_struct.
108 sig->utime = cputime_add(sig->utime, tsk->utime);
109 sig->stime = cputime_add(sig->stime, tsk->stime);
110 sig->gtime = cputime_add(sig->gtime, tsk->gtime);
111 sig->min_flt += tsk->min_flt;
112 sig->maj_flt += tsk->maj_flt;
113 sig->nvcsw += tsk->nvcsw;
114 sig->nivcsw += tsk->nivcsw;
115 sig->inblock += task_io_get_inblock(tsk);
116 sig->oublock += task_io_get_oublock(tsk);
117 sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
118 sig = NULL; /* Marker for below. */
121 __unhash_process(tsk);
123 tsk->signal = NULL;
124 tsk->sighand = NULL;
125 spin_unlock(&sighand->siglock);
126 rcu_read_unlock();
128 __cleanup_sighand(sighand);
129 clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
130 flush_sigqueue(&tsk->pending);
131 if (sig) {
132 flush_sigqueue(&sig->shared_pending);
133 taskstats_tgid_free(sig);
134 __cleanup_signal(sig);
138 static void delayed_put_task_struct(struct rcu_head *rhp)
140 put_task_struct(container_of(rhp, struct task_struct, rcu));
143 void release_task(struct task_struct * p)
145 struct task_struct *leader;
146 int zap_leader;
147 repeat:
148 atomic_dec(&p->user->processes);
149 proc_flush_task(p);
150 write_lock_irq(&tasklist_lock);
151 ptrace_unlink(p);
152 BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
153 __exit_signal(p);
156 * If we are the last non-leader member of the thread
157 * group, and the leader is zombie, then notify the
158 * group leader's parent process. (if it wants notification.)
160 zap_leader = 0;
161 leader = p->group_leader;
162 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
163 BUG_ON(leader->exit_signal == -1);
164 do_notify_parent(leader, leader->exit_signal);
166 * If we were the last child thread and the leader has
167 * exited already, and the leader's parent ignores SIGCHLD,
168 * then we are the one who should release the leader.
170 * do_notify_parent() will have marked it self-reaping in
171 * that case.
173 zap_leader = (leader->exit_signal == -1);
176 write_unlock_irq(&tasklist_lock);
177 release_thread(p);
178 call_rcu(&p->rcu, delayed_put_task_struct);
180 p = leader;
181 if (unlikely(zap_leader))
182 goto repeat;
186 * This checks not only the pgrp, but falls back on the pid if no
187 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
188 * without this...
190 * The caller must hold rcu lock or the tasklist lock.
192 struct pid *session_of_pgrp(struct pid *pgrp)
194 struct task_struct *p;
195 struct pid *sid = NULL;
197 p = pid_task(pgrp, PIDTYPE_PGID);
198 if (p == NULL)
199 p = pid_task(pgrp, PIDTYPE_PID);
200 if (p != NULL)
201 sid = task_session(p);
203 return sid;
207 * Determine if a process group is "orphaned", according to the POSIX
208 * definition in 2.2.2.52. Orphaned process groups are not to be affected
209 * by terminal-generated stop signals. Newly orphaned process groups are
210 * to receive a SIGHUP and a SIGCONT.
212 * "I ask you, have you ever known what it is to be an orphan?"
214 static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
216 struct task_struct *p;
218 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
219 if ((p == ignored_task) ||
220 (p->exit_state && thread_group_empty(p)) ||
221 is_global_init(p->real_parent))
222 continue;
224 if (task_pgrp(p->real_parent) != pgrp &&
225 task_session(p->real_parent) == task_session(p))
226 return 0;
227 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
229 return 1;
232 int is_current_pgrp_orphaned(void)
234 int retval;
236 read_lock(&tasklist_lock);
237 retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
238 read_unlock(&tasklist_lock);
240 return retval;
243 static int has_stopped_jobs(struct pid *pgrp)
245 int retval = 0;
246 struct task_struct *p;
248 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
249 if (!task_is_stopped(p))
250 continue;
251 retval = 1;
252 break;
253 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
254 return retval;
258 * Check to see if any process groups have become orphaned as
259 * a result of our exiting, and if they have any stopped jobs,
260 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
262 static void
263 kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
265 struct pid *pgrp = task_pgrp(tsk);
266 struct task_struct *ignored_task = tsk;
268 if (!parent)
269 /* exit: our father is in a different pgrp than
270 * we are and we were the only connection outside.
272 parent = tsk->real_parent;
273 else
274 /* reparent: our child is in a different pgrp than
275 * we are, and it was the only connection outside.
277 ignored_task = NULL;
279 if (task_pgrp(parent) != pgrp &&
280 task_session(parent) == task_session(tsk) &&
281 will_become_orphaned_pgrp(pgrp, ignored_task) &&
282 has_stopped_jobs(pgrp)) {
283 __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
284 __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
289 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
291 * If a kernel thread is launched as a result of a system call, or if
292 * it ever exits, it should generally reparent itself to kthreadd so it
293 * isn't in the way of other processes and is correctly cleaned up on exit.
295 * The various task state such as scheduling policy and priority may have
296 * been inherited from a user process, so we reset them to sane values here.
298 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
300 static void reparent_to_kthreadd(void)
302 write_lock_irq(&tasklist_lock);
304 ptrace_unlink(current);
305 /* Reparent to init */
306 remove_parent(current);
307 current->real_parent = current->parent = kthreadd_task;
308 add_parent(current);
310 /* Set the exit signal to SIGCHLD so we signal init on exit */
311 current->exit_signal = SIGCHLD;
313 if (task_nice(current) < 0)
314 set_user_nice(current, 0);
315 /* cpus_allowed? */
316 /* rt_priority? */
317 /* signals? */
318 security_task_reparent_to_init(current);
319 memcpy(current->signal->rlim, init_task.signal->rlim,
320 sizeof(current->signal->rlim));
321 atomic_inc(&(INIT_USER->__count));
322 write_unlock_irq(&tasklist_lock);
323 switch_uid(INIT_USER);
326 void __set_special_pids(struct pid *pid)
328 struct task_struct *curr = current->group_leader;
329 pid_t nr = pid_nr(pid);
331 if (task_session(curr) != pid) {
332 detach_pid(curr, PIDTYPE_SID);
333 attach_pid(curr, PIDTYPE_SID, pid);
334 set_task_session(curr, nr);
336 if (task_pgrp(curr) != pid) {
337 detach_pid(curr, PIDTYPE_PGID);
338 attach_pid(curr, PIDTYPE_PGID, pid);
339 set_task_pgrp(curr, nr);
343 static void set_special_pids(struct pid *pid)
345 write_lock_irq(&tasklist_lock);
346 __set_special_pids(pid);
347 write_unlock_irq(&tasklist_lock);
351 * Let kernel threads use this to say that they
352 * allow a certain signal (since daemonize() will
353 * have disabled all of them by default).
355 int allow_signal(int sig)
357 if (!valid_signal(sig) || sig < 1)
358 return -EINVAL;
360 spin_lock_irq(&current->sighand->siglock);
361 sigdelset(&current->blocked, sig);
362 if (!current->mm) {
363 /* Kernel threads handle their own signals.
364 Let the signal code know it'll be handled, so
365 that they don't get converted to SIGKILL or
366 just silently dropped */
367 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
369 recalc_sigpending();
370 spin_unlock_irq(&current->sighand->siglock);
371 return 0;
374 EXPORT_SYMBOL(allow_signal);
376 int disallow_signal(int sig)
378 if (!valid_signal(sig) || sig < 1)
379 return -EINVAL;
381 spin_lock_irq(&current->sighand->siglock);
382 current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
383 recalc_sigpending();
384 spin_unlock_irq(&current->sighand->siglock);
385 return 0;
388 EXPORT_SYMBOL(disallow_signal);
391 * Put all the gunge required to become a kernel thread without
392 * attached user resources in one place where it belongs.
395 void daemonize(const char *name, ...)
397 va_list args;
398 struct fs_struct *fs;
399 sigset_t blocked;
401 va_start(args, name);
402 vsnprintf(current->comm, sizeof(current->comm), name, args);
403 va_end(args);
406 * If we were started as result of loading a module, close all of the
407 * user space pages. We don't need them, and if we didn't close them
408 * they would be locked into memory.
410 exit_mm(current);
412 * We don't want to have TIF_FREEZE set if the system-wide hibernation
413 * or suspend transition begins right now.
415 current->flags |= PF_NOFREEZE;
417 if (current->nsproxy != &init_nsproxy) {
418 get_nsproxy(&init_nsproxy);
419 switch_task_namespaces(current, &init_nsproxy);
421 set_special_pids(&init_struct_pid);
422 proc_clear_tty(current);
424 /* Block and flush all signals */
425 sigfillset(&blocked);
426 sigprocmask(SIG_BLOCK, &blocked, NULL);
427 flush_signals(current);
429 /* Become as one with the init task */
431 exit_fs(current); /* current->fs->count--; */
432 fs = init_task.fs;
433 current->fs = fs;
434 atomic_inc(&fs->count);
436 exit_files(current);
437 current->files = init_task.files;
438 atomic_inc(&current->files->count);
440 reparent_to_kthreadd();
443 EXPORT_SYMBOL(daemonize);
445 static void close_files(struct files_struct * files)
447 int i, j;
448 struct fdtable *fdt;
450 j = 0;
453 * It is safe to dereference the fd table without RCU or
454 * ->file_lock because this is the last reference to the
455 * files structure.
457 fdt = files_fdtable(files);
458 for (;;) {
459 unsigned long set;
460 i = j * __NFDBITS;
461 if (i >= fdt->max_fds)
462 break;
463 set = fdt->open_fds->fds_bits[j++];
464 while (set) {
465 if (set & 1) {
466 struct file * file = xchg(&fdt->fd[i], NULL);
467 if (file) {
468 filp_close(file, files);
469 cond_resched();
472 i++;
473 set >>= 1;
478 struct files_struct *get_files_struct(struct task_struct *task)
480 struct files_struct *files;
482 task_lock(task);
483 files = task->files;
484 if (files)
485 atomic_inc(&files->count);
486 task_unlock(task);
488 return files;
491 void put_files_struct(struct files_struct *files)
493 struct fdtable *fdt;
495 if (atomic_dec_and_test(&files->count)) {
496 close_files(files);
498 * Free the fd and fdset arrays if we expanded them.
499 * If the fdtable was embedded, pass files for freeing
500 * at the end of the RCU grace period. Otherwise,
501 * you can free files immediately.
503 fdt = files_fdtable(files);
504 if (fdt != &files->fdtab)
505 kmem_cache_free(files_cachep, files);
506 free_fdtable(fdt);
510 EXPORT_SYMBOL(put_files_struct);
512 void reset_files_struct(struct task_struct *tsk, struct files_struct *files)
514 struct files_struct *old;
516 old = tsk->files;
517 task_lock(tsk);
518 tsk->files = files;
519 task_unlock(tsk);
520 put_files_struct(old);
522 EXPORT_SYMBOL(reset_files_struct);
524 static void __exit_files(struct task_struct *tsk)
526 struct files_struct * files = tsk->files;
528 if (files) {
529 task_lock(tsk);
530 tsk->files = NULL;
531 task_unlock(tsk);
532 put_files_struct(files);
536 void exit_files(struct task_struct *tsk)
538 __exit_files(tsk);
541 static void __put_fs_struct(struct fs_struct *fs)
543 /* No need to hold fs->lock if we are killing it */
544 if (atomic_dec_and_test(&fs->count)) {
545 path_put(&fs->root);
546 path_put(&fs->pwd);
547 if (fs->altroot.dentry)
548 path_put(&fs->altroot);
549 kmem_cache_free(fs_cachep, fs);
553 void put_fs_struct(struct fs_struct *fs)
555 __put_fs_struct(fs);
558 static void __exit_fs(struct task_struct *tsk)
560 struct fs_struct * fs = tsk->fs;
562 if (fs) {
563 task_lock(tsk);
564 tsk->fs = NULL;
565 task_unlock(tsk);
566 __put_fs_struct(fs);
570 void exit_fs(struct task_struct *tsk)
572 __exit_fs(tsk);
575 EXPORT_SYMBOL_GPL(exit_fs);
578 * Turn us into a lazy TLB process if we
579 * aren't already..
581 static void exit_mm(struct task_struct * tsk)
583 struct mm_struct *mm = tsk->mm;
585 mm_release(tsk, mm);
586 if (!mm)
587 return;
589 * Serialize with any possible pending coredump.
590 * We must hold mmap_sem around checking core_waiters
591 * and clearing tsk->mm. The core-inducing thread
592 * will increment core_waiters for each thread in the
593 * group with ->mm != NULL.
595 down_read(&mm->mmap_sem);
596 if (mm->core_waiters) {
597 up_read(&mm->mmap_sem);
598 down_write(&mm->mmap_sem);
599 if (!--mm->core_waiters)
600 complete(mm->core_startup_done);
601 up_write(&mm->mmap_sem);
603 wait_for_completion(&mm->core_done);
604 down_read(&mm->mmap_sem);
606 atomic_inc(&mm->mm_count);
607 BUG_ON(mm != tsk->active_mm);
608 /* more a memory barrier than a real lock */
609 task_lock(tsk);
610 tsk->mm = NULL;
611 up_read(&mm->mmap_sem);
612 enter_lazy_tlb(mm, current);
613 /* We don't want this task to be frozen prematurely */
614 clear_freeze_flag(tsk);
615 task_unlock(tsk);
616 mmput(mm);
619 static void
620 reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
622 if (p->pdeath_signal)
623 /* We already hold the tasklist_lock here. */
624 group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
626 /* Move the child from its dying parent to the new one. */
627 if (unlikely(traced)) {
628 /* Preserve ptrace links if someone else is tracing this child. */
629 list_del_init(&p->ptrace_list);
630 if (p->parent != p->real_parent)
631 list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
632 } else {
633 /* If this child is being traced, then we're the one tracing it
634 * anyway, so let go of it.
636 p->ptrace = 0;
637 remove_parent(p);
638 p->parent = p->real_parent;
639 add_parent(p);
641 if (task_is_traced(p)) {
643 * If it was at a trace stop, turn it into
644 * a normal stop since it's no longer being
645 * traced.
647 ptrace_untrace(p);
651 /* If this is a threaded reparent there is no need to
652 * notify anyone anything has happened.
654 if (p->real_parent->group_leader == father->group_leader)
655 return;
657 /* We don't want people slaying init. */
658 if (p->exit_signal != -1)
659 p->exit_signal = SIGCHLD;
661 /* If we'd notified the old parent about this child's death,
662 * also notify the new parent.
664 if (!traced && p->exit_state == EXIT_ZOMBIE &&
665 p->exit_signal != -1 && thread_group_empty(p))
666 do_notify_parent(p, p->exit_signal);
668 kill_orphaned_pgrp(p, father);
672 * When we die, we re-parent all our children.
673 * Try to give them to another thread in our thread
674 * group, and if no such member exists, give it to
675 * the child reaper process (ie "init") in our pid
676 * space.
678 static void forget_original_parent(struct task_struct *father)
680 struct task_struct *p, *n, *reaper = father;
681 struct list_head ptrace_dead;
683 INIT_LIST_HEAD(&ptrace_dead);
685 write_lock_irq(&tasklist_lock);
687 do {
688 reaper = next_thread(reaper);
689 if (reaper == father) {
690 reaper = task_child_reaper(father);
691 break;
693 } while (reaper->flags & PF_EXITING);
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_entry_safe(p, n, &father->children, sibling) {
704 int ptrace;
706 ptrace = p->ptrace;
708 /* if father isn't the real parent, then ptrace must be enabled */
709 BUG_ON(father != p->real_parent && !ptrace);
711 if (father == p->real_parent) {
712 /* reparent with a reaper, real father it's us */
713 p->real_parent = reaper;
714 reparent_thread(p, father, 0);
715 } else {
716 /* reparent ptraced task to its real parent */
717 __ptrace_unlink (p);
718 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
719 thread_group_empty(p))
720 do_notify_parent(p, p->exit_signal);
724 * if the ptraced child is a zombie with exit_signal == -1
725 * we must collect it before we exit, or it will remain
726 * zombie forever since we prevented it from self-reap itself
727 * while it was being traced by us, to be able to see it in wait4.
729 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
730 list_add(&p->ptrace_list, &ptrace_dead);
733 list_for_each_entry_safe(p, n, &father->ptrace_children, ptrace_list) {
734 p->real_parent = reaper;
735 reparent_thread(p, father, 1);
738 write_unlock_irq(&tasklist_lock);
739 BUG_ON(!list_empty(&father->children));
740 BUG_ON(!list_empty(&father->ptrace_children));
742 list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_list) {
743 list_del_init(&p->ptrace_list);
744 release_task(p);
750 * Send signals to all our closest relatives so that they know
751 * to properly mourn us..
753 static void exit_notify(struct task_struct *tsk, int group_dead)
755 int state;
758 * This does two things:
760 * A. Make init inherit all the child processes
761 * B. Check to see if any process groups have become orphaned
762 * as a result of our exiting, and if they have any stopped
763 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
765 forget_original_parent(tsk);
766 exit_task_namespaces(tsk);
768 write_lock_irq(&tasklist_lock);
769 if (group_dead)
770 kill_orphaned_pgrp(tsk->group_leader, NULL);
772 /* Let father know we died
774 * Thread signals are configurable, but you aren't going to use
775 * that to send signals to arbitary processes.
776 * That stops right now.
778 * If the parent exec id doesn't match the exec id we saved
779 * when we started then we know the parent has changed security
780 * domain.
782 * If our self_exec id doesn't match our parent_exec_id then
783 * we have changed execution domain as these two values started
784 * the same after a fork.
786 if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
787 (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
788 tsk->self_exec_id != tsk->parent_exec_id)
789 && !capable(CAP_KILL))
790 tsk->exit_signal = SIGCHLD;
793 /* If something other than our normal parent is ptracing us, then
794 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
795 * only has special meaning to our real parent.
797 if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
798 int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
799 do_notify_parent(tsk, signal);
800 } else if (tsk->ptrace) {
801 do_notify_parent(tsk, SIGCHLD);
804 state = EXIT_ZOMBIE;
805 if (tsk->exit_signal == -1 && likely(!tsk->ptrace))
806 state = EXIT_DEAD;
807 tsk->exit_state = state;
809 if (thread_group_leader(tsk) &&
810 tsk->signal->notify_count < 0 &&
811 tsk->signal->group_exit_task)
812 wake_up_process(tsk->signal->group_exit_task);
814 write_unlock_irq(&tasklist_lock);
816 /* If the process is dead, release it - nobody will wait for it */
817 if (state == EXIT_DEAD)
818 release_task(tsk);
821 #ifdef CONFIG_DEBUG_STACK_USAGE
822 static void check_stack_usage(void)
824 static DEFINE_SPINLOCK(low_water_lock);
825 static int lowest_to_date = THREAD_SIZE;
826 unsigned long *n = end_of_stack(current);
827 unsigned long free;
829 while (*n == 0)
830 n++;
831 free = (unsigned long)n - (unsigned long)end_of_stack(current);
833 if (free >= lowest_to_date)
834 return;
836 spin_lock(&low_water_lock);
837 if (free < lowest_to_date) {
838 printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
839 "left\n",
840 current->comm, free);
841 lowest_to_date = free;
843 spin_unlock(&low_water_lock);
845 #else
846 static inline void check_stack_usage(void) {}
847 #endif
849 static inline void exit_child_reaper(struct task_struct *tsk)
851 if (likely(tsk->group_leader != task_child_reaper(tsk)))
852 return;
854 if (tsk->nsproxy->pid_ns == &init_pid_ns)
855 panic("Attempted to kill init!");
858 * @tsk is the last thread in the 'cgroup-init' and is exiting.
859 * Terminate all remaining processes in the namespace and reap them
860 * before exiting @tsk.
862 * Note that @tsk (last thread of cgroup-init) may not necessarily
863 * be the child-reaper (i.e main thread of cgroup-init) of the
864 * namespace i.e the child_reaper may have already exited.
866 * Even after a child_reaper exits, we let it inherit orphaned children,
867 * because, pid_ns->child_reaper remains valid as long as there is
868 * at least one living sub-thread in the cgroup init.
870 * This living sub-thread of the cgroup-init will be notified when
871 * a child inherited by the 'child-reaper' exits (do_notify_parent()
872 * uses __group_send_sig_info()). Further, when reaping child processes,
873 * do_wait() iterates over children of all living sub threads.
875 * i.e even though 'child_reaper' thread is listed as the parent of the
876 * orphaned children, any living sub-thread in the cgroup-init can
877 * perform the role of the child_reaper.
879 zap_pid_ns_processes(tsk->nsproxy->pid_ns);
882 NORET_TYPE void do_exit(long code)
884 struct task_struct *tsk = current;
885 int group_dead;
887 profile_task_exit(tsk);
889 WARN_ON(atomic_read(&tsk->fs_excl));
891 if (unlikely(in_interrupt()))
892 panic("Aiee, killing interrupt handler!");
893 if (unlikely(!tsk->pid))
894 panic("Attempted to kill the idle task!");
896 if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
897 current->ptrace_message = code;
898 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
902 * We're taking recursive faults here in do_exit. Safest is to just
903 * leave this task alone and wait for reboot.
905 if (unlikely(tsk->flags & PF_EXITING)) {
906 printk(KERN_ALERT
907 "Fixing recursive fault but reboot is needed!\n");
909 * We can do this unlocked here. The futex code uses
910 * this flag just to verify whether the pi state
911 * cleanup has been done or not. In the worst case it
912 * loops once more. We pretend that the cleanup was
913 * done as there is no way to return. Either the
914 * OWNER_DIED bit is set by now or we push the blocked
915 * task into the wait for ever nirwana as well.
917 tsk->flags |= PF_EXITPIDONE;
918 if (tsk->io_context)
919 exit_io_context();
920 set_current_state(TASK_UNINTERRUPTIBLE);
921 schedule();
924 exit_signals(tsk); /* sets PF_EXITING */
926 * tsk->flags are checked in the futex code to protect against
927 * an exiting task cleaning up the robust pi futexes.
929 smp_mb();
930 spin_unlock_wait(&tsk->pi_lock);
932 if (unlikely(in_atomic()))
933 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
934 current->comm, task_pid_nr(current),
935 preempt_count());
937 acct_update_integrals(tsk);
938 if (tsk->mm) {
939 update_hiwater_rss(tsk->mm);
940 update_hiwater_vm(tsk->mm);
942 group_dead = atomic_dec_and_test(&tsk->signal->live);
943 if (group_dead) {
944 exit_child_reaper(tsk);
945 hrtimer_cancel(&tsk->signal->real_timer);
946 exit_itimers(tsk->signal);
948 acct_collect(code, group_dead);
949 #ifdef CONFIG_FUTEX
950 if (unlikely(tsk->robust_list))
951 exit_robust_list(tsk);
952 #ifdef CONFIG_COMPAT
953 if (unlikely(tsk->compat_robust_list))
954 compat_exit_robust_list(tsk);
955 #endif
956 #endif
957 if (group_dead)
958 tty_audit_exit();
959 if (unlikely(tsk->audit_context))
960 audit_free(tsk);
962 tsk->exit_code = code;
963 taskstats_exit(tsk, group_dead);
965 exit_mm(tsk);
967 if (group_dead)
968 acct_process();
969 exit_sem(tsk);
970 __exit_files(tsk);
971 __exit_fs(tsk);
972 check_stack_usage();
973 exit_thread();
974 cgroup_exit(tsk, 1);
975 exit_keys(tsk);
977 if (group_dead && tsk->signal->leader)
978 disassociate_ctty(1);
980 module_put(task_thread_info(tsk)->exec_domain->module);
981 if (tsk->binfmt)
982 module_put(tsk->binfmt->module);
984 proc_exit_connector(tsk);
985 exit_notify(tsk, group_dead);
986 #ifdef CONFIG_NUMA
987 mpol_free(tsk->mempolicy);
988 tsk->mempolicy = NULL;
989 #endif
990 #ifdef CONFIG_FUTEX
992 * This must happen late, after the PID is not
993 * hashed anymore:
995 if (unlikely(!list_empty(&tsk->pi_state_list)))
996 exit_pi_state_list(tsk);
997 if (unlikely(current->pi_state_cache))
998 kfree(current->pi_state_cache);
999 #endif
1001 * Make sure we are holding no locks:
1003 debug_check_no_locks_held(tsk);
1005 * We can do this unlocked here. The futex code uses this flag
1006 * just to verify whether the pi state cleanup has been done
1007 * or not. In the worst case it loops once more.
1009 tsk->flags |= PF_EXITPIDONE;
1011 if (tsk->io_context)
1012 exit_io_context();
1014 if (tsk->splice_pipe)
1015 __free_pipe_info(tsk->splice_pipe);
1017 preempt_disable();
1018 /* causes final put_task_struct in finish_task_switch(). */
1019 tsk->state = TASK_DEAD;
1021 schedule();
1022 BUG();
1023 /* Avoid "noreturn function does return". */
1024 for (;;)
1025 cpu_relax(); /* For when BUG is null */
1028 EXPORT_SYMBOL_GPL(do_exit);
1030 NORET_TYPE void complete_and_exit(struct completion *comp, long code)
1032 if (comp)
1033 complete(comp);
1035 do_exit(code);
1038 EXPORT_SYMBOL(complete_and_exit);
1040 asmlinkage long sys_exit(int error_code)
1042 do_exit((error_code&0xff)<<8);
1046 * Take down every thread in the group. This is called by fatal signals
1047 * as well as by sys_exit_group (below).
1049 NORET_TYPE void
1050 do_group_exit(int exit_code)
1052 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
1054 if (current->signal->flags & SIGNAL_GROUP_EXIT)
1055 exit_code = current->signal->group_exit_code;
1056 else if (!thread_group_empty(current)) {
1057 struct signal_struct *const sig = current->signal;
1058 struct sighand_struct *const sighand = current->sighand;
1059 spin_lock_irq(&sighand->siglock);
1060 if (signal_group_exit(sig))
1061 /* Another thread got here before we took the lock. */
1062 exit_code = sig->group_exit_code;
1063 else {
1064 sig->group_exit_code = exit_code;
1065 sig->flags = SIGNAL_GROUP_EXIT;
1066 zap_other_threads(current);
1068 spin_unlock_irq(&sighand->siglock);
1071 do_exit(exit_code);
1072 /* NOTREACHED */
1076 * this kills every thread in the thread group. Note that any externally
1077 * wait4()-ing process will get the correct exit code - even if this
1078 * thread is not the thread group leader.
1080 asmlinkage void sys_exit_group(int error_code)
1082 do_group_exit((error_code & 0xff) << 8);
1085 static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
1087 struct pid *pid = NULL;
1088 if (type == PIDTYPE_PID)
1089 pid = task->pids[type].pid;
1090 else if (type < PIDTYPE_MAX)
1091 pid = task->group_leader->pids[type].pid;
1092 return pid;
1095 static int eligible_child(enum pid_type type, struct pid *pid, int options,
1096 struct task_struct *p)
1098 int err;
1100 if (type < PIDTYPE_MAX) {
1101 if (task_pid_type(p, type) != pid)
1102 return 0;
1106 * Do not consider detached threads that are
1107 * not ptraced:
1109 if (p->exit_signal == -1 && !p->ptrace)
1110 return 0;
1112 /* Wait for all children (clone and not) if __WALL is set;
1113 * otherwise, wait for clone children *only* if __WCLONE is
1114 * set; otherwise, wait for non-clone children *only*. (Note:
1115 * A "clone" child here is one that reports to its parent
1116 * using a signal other than SIGCHLD.) */
1117 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
1118 && !(options & __WALL))
1119 return 0;
1121 err = security_task_wait(p);
1122 if (likely(!err))
1123 return 1;
1125 if (type != PIDTYPE_PID)
1126 return 0;
1127 /* This child was explicitly requested, abort */
1128 read_unlock(&tasklist_lock);
1129 return err;
1132 static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
1133 int why, int status,
1134 struct siginfo __user *infop,
1135 struct rusage __user *rusagep)
1137 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
1139 put_task_struct(p);
1140 if (!retval)
1141 retval = put_user(SIGCHLD, &infop->si_signo);
1142 if (!retval)
1143 retval = put_user(0, &infop->si_errno);
1144 if (!retval)
1145 retval = put_user((short)why, &infop->si_code);
1146 if (!retval)
1147 retval = put_user(pid, &infop->si_pid);
1148 if (!retval)
1149 retval = put_user(uid, &infop->si_uid);
1150 if (!retval)
1151 retval = put_user(status, &infop->si_status);
1152 if (!retval)
1153 retval = pid;
1154 return retval;
1158 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1159 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1160 * the lock and this task is uninteresting. If we return nonzero, we have
1161 * released the lock and the system call should return.
1163 static int wait_task_zombie(struct task_struct *p, int noreap,
1164 struct siginfo __user *infop,
1165 int __user *stat_addr, struct rusage __user *ru)
1167 unsigned long state;
1168 int retval, status, traced;
1169 pid_t pid = task_pid_vnr(p);
1171 if (unlikely(noreap)) {
1172 uid_t uid = p->uid;
1173 int exit_code = p->exit_code;
1174 int why, status;
1176 get_task_struct(p);
1177 read_unlock(&tasklist_lock);
1178 if ((exit_code & 0x7f) == 0) {
1179 why = CLD_EXITED;
1180 status = exit_code >> 8;
1181 } else {
1182 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1183 status = exit_code & 0x7f;
1185 return wait_noreap_copyout(p, pid, uid, why,
1186 status, infop, ru);
1190 * Try to move the task's state to DEAD
1191 * only one thread is allowed to do this:
1193 state = xchg(&p->exit_state, EXIT_DEAD);
1194 if (state != EXIT_ZOMBIE) {
1195 BUG_ON(state != EXIT_DEAD);
1196 return 0;
1199 /* traced means p->ptrace, but not vice versa */
1200 traced = (p->real_parent != p->parent);
1202 if (likely(!traced)) {
1203 struct signal_struct *psig;
1204 struct signal_struct *sig;
1207 * The resource counters for the group leader are in its
1208 * own task_struct. Those for dead threads in the group
1209 * are in its signal_struct, as are those for the child
1210 * processes it has previously reaped. All these
1211 * accumulate in the parent's signal_struct c* fields.
1213 * We don't bother to take a lock here to protect these
1214 * p->signal fields, because they are only touched by
1215 * __exit_signal, which runs with tasklist_lock
1216 * write-locked anyway, and so is excluded here. We do
1217 * need to protect the access to p->parent->signal fields,
1218 * as other threads in the parent group can be right
1219 * here reaping other children at the same time.
1221 spin_lock_irq(&p->parent->sighand->siglock);
1222 psig = p->parent->signal;
1223 sig = p->signal;
1224 psig->cutime =
1225 cputime_add(psig->cutime,
1226 cputime_add(p->utime,
1227 cputime_add(sig->utime,
1228 sig->cutime)));
1229 psig->cstime =
1230 cputime_add(psig->cstime,
1231 cputime_add(p->stime,
1232 cputime_add(sig->stime,
1233 sig->cstime)));
1234 psig->cgtime =
1235 cputime_add(psig->cgtime,
1236 cputime_add(p->gtime,
1237 cputime_add(sig->gtime,
1238 sig->cgtime)));
1239 psig->cmin_flt +=
1240 p->min_flt + sig->min_flt + sig->cmin_flt;
1241 psig->cmaj_flt +=
1242 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1243 psig->cnvcsw +=
1244 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1245 psig->cnivcsw +=
1246 p->nivcsw + sig->nivcsw + sig->cnivcsw;
1247 psig->cinblock +=
1248 task_io_get_inblock(p) +
1249 sig->inblock + sig->cinblock;
1250 psig->coublock +=
1251 task_io_get_oublock(p) +
1252 sig->oublock + sig->coublock;
1253 spin_unlock_irq(&p->parent->sighand->siglock);
1257 * Now we are sure this task is interesting, and no other
1258 * thread can reap it because we set its state to EXIT_DEAD.
1260 read_unlock(&tasklist_lock);
1262 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1263 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1264 ? p->signal->group_exit_code : p->exit_code;
1265 if (!retval && stat_addr)
1266 retval = put_user(status, stat_addr);
1267 if (!retval && infop)
1268 retval = put_user(SIGCHLD, &infop->si_signo);
1269 if (!retval && infop)
1270 retval = put_user(0, &infop->si_errno);
1271 if (!retval && infop) {
1272 int why;
1274 if ((status & 0x7f) == 0) {
1275 why = CLD_EXITED;
1276 status >>= 8;
1277 } else {
1278 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1279 status &= 0x7f;
1281 retval = put_user((short)why, &infop->si_code);
1282 if (!retval)
1283 retval = put_user(status, &infop->si_status);
1285 if (!retval && infop)
1286 retval = put_user(pid, &infop->si_pid);
1287 if (!retval && infop)
1288 retval = put_user(p->uid, &infop->si_uid);
1289 if (!retval)
1290 retval = pid;
1292 if (traced) {
1293 write_lock_irq(&tasklist_lock);
1294 /* We dropped tasklist, ptracer could die and untrace */
1295 ptrace_unlink(p);
1297 * If this is not a detached task, notify the parent.
1298 * If it's still not detached after that, don't release
1299 * it now.
1301 if (p->exit_signal != -1) {
1302 do_notify_parent(p, p->exit_signal);
1303 if (p->exit_signal != -1) {
1304 p->exit_state = EXIT_ZOMBIE;
1305 p = NULL;
1308 write_unlock_irq(&tasklist_lock);
1310 if (p != NULL)
1311 release_task(p);
1313 return retval;
1317 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1318 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1319 * the lock and this task is uninteresting. If we return nonzero, we have
1320 * released the lock and the system call should return.
1322 static int wait_task_stopped(struct task_struct *p,
1323 int noreap, struct siginfo __user *infop,
1324 int __user *stat_addr, struct rusage __user *ru)
1326 int retval, exit_code, why;
1327 uid_t uid = 0; /* unneeded, required by compiler */
1328 pid_t pid;
1330 exit_code = 0;
1331 spin_lock_irq(&p->sighand->siglock);
1333 if (unlikely(!task_is_stopped_or_traced(p)))
1334 goto unlock_sig;
1336 if (!(p->ptrace & PT_PTRACED) && p->signal->group_stop_count > 0)
1338 * A group stop is in progress and this is the group leader.
1339 * We won't report until all threads have stopped.
1341 goto unlock_sig;
1343 exit_code = p->exit_code;
1344 if (!exit_code)
1345 goto unlock_sig;
1347 if (!noreap)
1348 p->exit_code = 0;
1350 uid = p->uid;
1351 unlock_sig:
1352 spin_unlock_irq(&p->sighand->siglock);
1353 if (!exit_code)
1354 return 0;
1357 * Now we are pretty sure this task is interesting.
1358 * Make sure it doesn't get reaped out from under us while we
1359 * give up the lock and then examine it below. We don't want to
1360 * keep holding onto the tasklist_lock while we call getrusage and
1361 * possibly take page faults for user memory.
1363 get_task_struct(p);
1364 pid = task_pid_vnr(p);
1365 why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
1366 read_unlock(&tasklist_lock);
1368 if (unlikely(noreap))
1369 return wait_noreap_copyout(p, pid, uid,
1370 why, exit_code,
1371 infop, ru);
1373 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1374 if (!retval && stat_addr)
1375 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1376 if (!retval && infop)
1377 retval = put_user(SIGCHLD, &infop->si_signo);
1378 if (!retval && infop)
1379 retval = put_user(0, &infop->si_errno);
1380 if (!retval && infop)
1381 retval = put_user(why, &infop->si_code);
1382 if (!retval && infop)
1383 retval = put_user(exit_code, &infop->si_status);
1384 if (!retval && infop)
1385 retval = put_user(pid, &infop->si_pid);
1386 if (!retval && infop)
1387 retval = put_user(uid, &infop->si_uid);
1388 if (!retval)
1389 retval = pid;
1390 put_task_struct(p);
1392 BUG_ON(!retval);
1393 return retval;
1397 * Handle do_wait work for one task in a live, non-stopped state.
1398 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1399 * the lock and this task is uninteresting. If we return nonzero, we have
1400 * released the lock and the system call should return.
1402 static int wait_task_continued(struct task_struct *p, int noreap,
1403 struct siginfo __user *infop,
1404 int __user *stat_addr, struct rusage __user *ru)
1406 int retval;
1407 pid_t pid;
1408 uid_t uid;
1410 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1411 return 0;
1413 spin_lock_irq(&p->sighand->siglock);
1414 /* Re-check with the lock held. */
1415 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1416 spin_unlock_irq(&p->sighand->siglock);
1417 return 0;
1419 if (!noreap)
1420 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1421 spin_unlock_irq(&p->sighand->siglock);
1423 pid = task_pid_vnr(p);
1424 uid = p->uid;
1425 get_task_struct(p);
1426 read_unlock(&tasklist_lock);
1428 if (!infop) {
1429 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1430 put_task_struct(p);
1431 if (!retval && stat_addr)
1432 retval = put_user(0xffff, stat_addr);
1433 if (!retval)
1434 retval = pid;
1435 } else {
1436 retval = wait_noreap_copyout(p, pid, uid,
1437 CLD_CONTINUED, SIGCONT,
1438 infop, ru);
1439 BUG_ON(retval == 0);
1442 return retval;
1445 static long do_wait(enum pid_type type, struct pid *pid, int options,
1446 struct siginfo __user *infop, int __user *stat_addr,
1447 struct rusage __user *ru)
1449 DECLARE_WAITQUEUE(wait, current);
1450 struct task_struct *tsk;
1451 int flag, retval;
1453 add_wait_queue(&current->signal->wait_chldexit,&wait);
1454 repeat:
1455 /* If there is nothing that can match our critier just get out */
1456 retval = -ECHILD;
1457 if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type])))
1458 goto end;
1461 * We will set this flag if we see any child that might later
1462 * match our criteria, even if we are not able to reap it yet.
1464 flag = retval = 0;
1465 current->state = TASK_INTERRUPTIBLE;
1466 read_lock(&tasklist_lock);
1467 tsk = current;
1468 do {
1469 struct task_struct *p;
1471 list_for_each_entry(p, &tsk->children, sibling) {
1472 int ret = eligible_child(type, pid, options, p);
1473 if (!ret)
1474 continue;
1476 if (unlikely(ret < 0)) {
1477 retval = ret;
1478 } else if (task_is_stopped_or_traced(p)) {
1480 * It's stopped now, so it might later
1481 * continue, exit, or stop again.
1483 flag = 1;
1484 if (!(p->ptrace & PT_PTRACED) &&
1485 !(options & WUNTRACED))
1486 continue;
1488 retval = wait_task_stopped(p,
1489 (options & WNOWAIT), infop,
1490 stat_addr, ru);
1491 } else if (p->exit_state == EXIT_ZOMBIE &&
1492 !delay_group_leader(p)) {
1494 * We don't reap group leaders with subthreads.
1496 if (!likely(options & WEXITED))
1497 continue;
1498 retval = wait_task_zombie(p,
1499 (options & WNOWAIT), infop,
1500 stat_addr, ru);
1501 } else if (p->exit_state != EXIT_DEAD) {
1503 * It's running now, so it might later
1504 * exit, stop, or stop and then continue.
1506 flag = 1;
1507 if (!unlikely(options & WCONTINUED))
1508 continue;
1509 retval = wait_task_continued(p,
1510 (options & WNOWAIT), infop,
1511 stat_addr, ru);
1513 if (retval != 0) /* tasklist_lock released */
1514 goto end;
1516 if (!flag) {
1517 list_for_each_entry(p, &tsk->ptrace_children,
1518 ptrace_list) {
1519 flag = eligible_child(type, pid, options, p);
1520 if (!flag)
1521 continue;
1522 if (likely(flag > 0))
1523 break;
1524 retval = flag;
1525 goto end;
1528 if (options & __WNOTHREAD)
1529 break;
1530 tsk = next_thread(tsk);
1531 BUG_ON(tsk->signal != current->signal);
1532 } while (tsk != current);
1533 read_unlock(&tasklist_lock);
1535 if (flag) {
1536 if (options & WNOHANG)
1537 goto end;
1538 retval = -ERESTARTSYS;
1539 if (signal_pending(current))
1540 goto end;
1541 schedule();
1542 goto repeat;
1544 retval = -ECHILD;
1545 end:
1546 current->state = TASK_RUNNING;
1547 remove_wait_queue(&current->signal->wait_chldexit,&wait);
1548 if (infop) {
1549 if (retval > 0)
1550 retval = 0;
1551 else {
1553 * For a WNOHANG return, clear out all the fields
1554 * we would set so the user can easily tell the
1555 * difference.
1557 if (!retval)
1558 retval = put_user(0, &infop->si_signo);
1559 if (!retval)
1560 retval = put_user(0, &infop->si_errno);
1561 if (!retval)
1562 retval = put_user(0, &infop->si_code);
1563 if (!retval)
1564 retval = put_user(0, &infop->si_pid);
1565 if (!retval)
1566 retval = put_user(0, &infop->si_uid);
1567 if (!retval)
1568 retval = put_user(0, &infop->si_status);
1571 return retval;
1574 asmlinkage long sys_waitid(int which, pid_t upid,
1575 struct siginfo __user *infop, int options,
1576 struct rusage __user *ru)
1578 struct pid *pid = NULL;
1579 enum pid_type type;
1580 long ret;
1582 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1583 return -EINVAL;
1584 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1585 return -EINVAL;
1587 switch (which) {
1588 case P_ALL:
1589 type = PIDTYPE_MAX;
1590 break;
1591 case P_PID:
1592 type = PIDTYPE_PID;
1593 if (upid <= 0)
1594 return -EINVAL;
1595 break;
1596 case P_PGID:
1597 type = PIDTYPE_PGID;
1598 if (upid <= 0)
1599 return -EINVAL;
1600 break;
1601 default:
1602 return -EINVAL;
1605 if (type < PIDTYPE_MAX)
1606 pid = find_get_pid(upid);
1607 ret = do_wait(type, pid, options, infop, NULL, ru);
1608 put_pid(pid);
1610 /* avoid REGPARM breakage on x86: */
1611 prevent_tail_call(ret);
1612 return ret;
1615 asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr,
1616 int options, struct rusage __user *ru)
1618 struct pid *pid = NULL;
1619 enum pid_type type;
1620 long ret;
1622 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1623 __WNOTHREAD|__WCLONE|__WALL))
1624 return -EINVAL;
1626 if (upid == -1)
1627 type = PIDTYPE_MAX;
1628 else if (upid < 0) {
1629 type = PIDTYPE_PGID;
1630 pid = find_get_pid(-upid);
1631 } else if (upid == 0) {
1632 type = PIDTYPE_PGID;
1633 pid = get_pid(task_pgrp(current));
1634 } else /* upid > 0 */ {
1635 type = PIDTYPE_PID;
1636 pid = find_get_pid(upid);
1639 ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
1640 put_pid(pid);
1642 /* avoid REGPARM breakage on x86: */
1643 prevent_tail_call(ret);
1644 return ret;
1647 #ifdef __ARCH_WANT_SYS_WAITPID
1650 * sys_waitpid() remains for compatibility. waitpid() should be
1651 * implemented by calling sys_wait4() from libc.a.
1653 asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
1655 return sys_wait4(pid, stat_addr, options, NULL);
1658 #endif