projects/linux·blob cf025109 · refs

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1/*
2 * linux/kernel/exit.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/config.h>
8#include <linux/mm.h>
9#include <linux/slab.h>
10#include <linux/interrupt.h>
11#include <linux/smp_lock.h>
12#include <linux/module.h>
13#include <linux/completion.h>
14#include <linux/personality.h>
15#include <linux/tty.h>
16#include <linux/namespace.h>
17#include <linux/key.h>
18#include <linux/security.h>
19#include <linux/cpu.h>
20#include <linux/acct.h>
21#include <linux/file.h>
22#include <linux/binfmts.h>
23#include <linux/ptrace.h>
24#include <linux/profile.h>
25#include <linux/mount.h>
26#include <linux/proc_fs.h>
27#include <linux/mempolicy.h>
28#include <linux/cpuset.h>
29#include <linux/syscalls.h>
30
31#include <asm/uaccess.h>
32#include <asm/unistd.h>
33#include <asm/pgtable.h>
34#include <asm/mmu_context.h>
35
36extern void sem_exit (void);
37extern struct task_struct *child_reaper;
38
39int getrusage(struct task_struct *, int, struct rusage __user *);
40
41static void __unhash_process(struct task_struct *p)
42{
43 nr_threads--;
44 detach_pid(p, PIDTYPE_PID);
45 detach_pid(p, PIDTYPE_TGID);
46 if (thread_group_leader(p)) {
47 detach_pid(p, PIDTYPE_PGID);
48 detach_pid(p, PIDTYPE_SID);
49 if (p->pid)
50 __get_cpu_var(process_counts)--;
51 }
52
53 REMOVE_LINKS(p);
54}
55
56void release_task(struct task_struct * p)
57{
58 int zap_leader;
59 task_t *leader;
60 struct dentry *proc_dentry;
61
62repeat:
63 atomic_dec(&p->user->processes);
64 spin_lock(&p->proc_lock);
65 proc_dentry = proc_pid_unhash(p);
66 write_lock_irq(&tasklist_lock);
67 if (unlikely(p->ptrace))
68 __ptrace_unlink(p);
69 BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
70 __exit_signal(p);
71 __exit_sighand(p);
72 __unhash_process(p);
73
74 /*
75 * If we are the last non-leader member of the thread
76 * group, and the leader is zombie, then notify the
77 * group leader's parent process. (if it wants notification.)
78 */
79 zap_leader = 0;
80 leader = p->group_leader;
81 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
82 BUG_ON(leader->exit_signal == -1);
83 do_notify_parent(leader, leader->exit_signal);
84 /*
85 * If we were the last child thread and the leader has
86 * exited already, and the leader's parent ignores SIGCHLD,
87 * then we are the one who should release the leader.
88 *
89 * do_notify_parent() will have marked it self-reaping in
90 * that case.
91 */
92 zap_leader = (leader->exit_signal == -1);
93 }
94
95 sched_exit(p);
96 write_unlock_irq(&tasklist_lock);
97 spin_unlock(&p->proc_lock);
98 proc_pid_flush(proc_dentry);
99 release_thread(p);
100 put_task_struct(p);
101
102 p = leader;
103 if (unlikely(zap_leader))
104 goto repeat;
105}
106
107/* we are using it only for SMP init */
108
109void unhash_process(struct task_struct *p)
110{
111 struct dentry *proc_dentry;
112
113 spin_lock(&p->proc_lock);
114 proc_dentry = proc_pid_unhash(p);
115 write_lock_irq(&tasklist_lock);
116 __unhash_process(p);
117 write_unlock_irq(&tasklist_lock);
118 spin_unlock(&p->proc_lock);
119 proc_pid_flush(proc_dentry);
120}
121
122/*
123 * This checks not only the pgrp, but falls back on the pid if no
124 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
125 * without this...
126 */
127int session_of_pgrp(int pgrp)
128{
129 struct task_struct *p;
130 int sid = -1;
131
132 read_lock(&tasklist_lock);
133 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
134 if (p->signal->session > 0) {
135 sid = p->signal->session;
136 goto out;
137 }
138 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
139 p = find_task_by_pid(pgrp);
140 if (p)
141 sid = p->signal->session;
142out:
143 read_unlock(&tasklist_lock);
144
145 return sid;
146}
147
148/*
149 * Determine if a process group is "orphaned", according to the POSIX
150 * definition in 2.2.2.52. Orphaned process groups are not to be affected
151 * by terminal-generated stop signals. Newly orphaned process groups are
152 * to receive a SIGHUP and a SIGCONT.
153 *
154 * "I ask you, have you ever known what it is to be an orphan?"
155 */
156static int will_become_orphaned_pgrp(int pgrp, task_t *ignored_task)
157{
158 struct task_struct *p;
159 int ret = 1;
160
161 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
162 if (p == ignored_task
163 || p->exit_state
164 || p->real_parent->pid == 1)
165 continue;
166 if (process_group(p->real_parent) != pgrp
167 && p->real_parent->signal->session == p->signal->session) {
168 ret = 0;
169 break;
170 }
171 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
172 return ret; /* (sighing) "Often!" */
173}
174
175int is_orphaned_pgrp(int pgrp)
176{
177 int retval;
178
179 read_lock(&tasklist_lock);
180 retval = will_become_orphaned_pgrp(pgrp, NULL);
181 read_unlock(&tasklist_lock);
182
183 return retval;
184}
185
186static inline int has_stopped_jobs(int pgrp)
187{
188 int retval = 0;
189 struct task_struct *p;
190
191 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
192 if (p->state != TASK_STOPPED)
193 continue;
194
195 /* If p is stopped by a debugger on a signal that won't
196 stop it, then don't count p as stopped. This isn't
197 perfect but it's a good approximation. */
198 if (unlikely (p->ptrace)
199 && p->exit_code != SIGSTOP
200 && p->exit_code != SIGTSTP
201 && p->exit_code != SIGTTOU
202 && p->exit_code != SIGTTIN)
203 continue;
204
205 retval = 1;
206 break;
207 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
208 return retval;
209}
210
211/**
212 * reparent_to_init() - Reparent the calling kernel thread to the init task.
213 *
214 * If a kernel thread is launched as a result of a system call, or if
215 * it ever exits, it should generally reparent itself to init so that
216 * it is correctly cleaned up on exit.
217 *
218 * The various task state such as scheduling policy and priority may have
219 * been inherited from a user process, so we reset them to sane values here.
220 *
221 * NOTE that reparent_to_init() gives the caller full capabilities.
222 */
223static inline void reparent_to_init(void)
224{
225 write_lock_irq(&tasklist_lock);
226
227 ptrace_unlink(current);
228 /* Reparent to init */
229 REMOVE_LINKS(current);
230 current->parent = child_reaper;
231 current->real_parent = child_reaper;
232 SET_LINKS(current);
233
234 /* Set the exit signal to SIGCHLD so we signal init on exit */
235 current->exit_signal = SIGCHLD;
236
237 if ((current->policy == SCHED_NORMAL) && (task_nice(current) < 0))
238 set_user_nice(current, 0);
239 /* cpus_allowed? */
240 /* rt_priority? */
241 /* signals? */
242 security_task_reparent_to_init(current);
243 memcpy(current->signal->rlim, init_task.signal->rlim,
244 sizeof(current->signal->rlim));
245 atomic_inc(&(INIT_USER->__count));
246 write_unlock_irq(&tasklist_lock);
247 switch_uid(INIT_USER);
248}
249
250void __set_special_pids(pid_t session, pid_t pgrp)
251{
252 struct task_struct *curr = current;
253
254 if (curr->signal->session != session) {
255 detach_pid(curr, PIDTYPE_SID);
256 curr->signal->session = session;
257 attach_pid(curr, PIDTYPE_SID, session);
258 }
259 if (process_group(curr) != pgrp) {
260 detach_pid(curr, PIDTYPE_PGID);
261 curr->signal->pgrp = pgrp;
262 attach_pid(curr, PIDTYPE_PGID, pgrp);
263 }
264}
265
266void set_special_pids(pid_t session, pid_t pgrp)
267{
268 write_lock_irq(&tasklist_lock);
269 __set_special_pids(session, pgrp);
270 write_unlock_irq(&tasklist_lock);
271}
272
273/*
274 * Let kernel threads use this to say that they
275 * allow a certain signal (since daemonize() will
276 * have disabled all of them by default).
277 */
278int allow_signal(int sig)
279{
280 if (sig < 1 || sig > _NSIG)
281 return -EINVAL;
282
283 spin_lock_irq(&current->sighand->siglock);
284 sigdelset(&current->blocked, sig);
285 if (!current->mm) {
286 /* Kernel threads handle their own signals.
287 Let the signal code know it'll be handled, so
288 that they don't get converted to SIGKILL or
289 just silently dropped */
290 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
291 }
292 recalc_sigpending();
293 spin_unlock_irq(&current->sighand->siglock);
294 return 0;
295}
296
297EXPORT_SYMBOL(allow_signal);
298
299int disallow_signal(int sig)
300{
301 if (sig < 1 || sig > _NSIG)
302 return -EINVAL;
303
304 spin_lock_irq(&current->sighand->siglock);
305 sigaddset(&current->blocked, sig);
306 recalc_sigpending();
307 spin_unlock_irq(&current->sighand->siglock);
308 return 0;
309}
310
311EXPORT_SYMBOL(disallow_signal);
312
313/*
314 * Put all the gunge required to become a kernel thread without
315 * attached user resources in one place where it belongs.
316 */
317
318void daemonize(const char *name, ...)
319{
320 va_list args;
321 struct fs_struct *fs;
322 sigset_t blocked;
323
324 va_start(args, name);
325 vsnprintf(current->comm, sizeof(current->comm), name, args);
326 va_end(args);
327
328 /*
329 * If we were started as result of loading a module, close all of the
330 * user space pages. We don't need them, and if we didn't close them
331 * they would be locked into memory.
332 */
333 exit_mm(current);
334
335 set_special_pids(1, 1);
336 down(&tty_sem);
337 current->signal->tty = NULL;
338 up(&tty_sem);
339
340 /* Block and flush all signals */
341 sigfillset(&blocked);
342 sigprocmask(SIG_BLOCK, &blocked, NULL);
343 flush_signals(current);
344
345 /* Become as one with the init task */
346
347 exit_fs(current); /* current->fs->count--; */
348 fs = init_task.fs;
349 current->fs = fs;
350 atomic_inc(&fs->count);
351 exit_files(current);
352 current->files = init_task.files;
353 atomic_inc(&current->files->count);
354
355 reparent_to_init();
356}
357
358EXPORT_SYMBOL(daemonize);
359
360static inline void close_files(struct files_struct * files)
361{
362 int i, j;
363
364 j = 0;
365 for (;;) {
366 unsigned long set;
367 i = j * __NFDBITS;
368 if (i >= files->max_fdset || i >= files->max_fds)
369 break;
370 set = files->open_fds->fds_bits[j++];
371 while (set) {
372 if (set & 1) {
373 struct file * file = xchg(&files->fd[i], NULL);
374 if (file)
375 filp_close(file, files);
376 }
377 i++;
378 set >>= 1;
379 }
380 }
381}
382
383struct files_struct *get_files_struct(struct task_struct *task)
384{
385 struct files_struct *files;
386
387 task_lock(task);
388 files = task->files;
389 if (files)
390 atomic_inc(&files->count);
391 task_unlock(task);
392
393 return files;
394}
395
396void fastcall put_files_struct(struct files_struct *files)
397{
398 if (atomic_dec_and_test(&files->count)) {
399 close_files(files);
400 /*
401 * Free the fd and fdset arrays if we expanded them.
402 */
403 if (files->fd != &files->fd_array[0])
404 free_fd_array(files->fd, files->max_fds);
405 if (files->max_fdset > __FD_SETSIZE) {
406 free_fdset(files->open_fds, files->max_fdset);
407 free_fdset(files->close_on_exec, files->max_fdset);
408 }
409 kmem_cache_free(files_cachep, files);
410 }
411}
412
413EXPORT_SYMBOL(put_files_struct);
414
415static inline void __exit_files(struct task_struct *tsk)
416{
417 struct files_struct * files = tsk->files;
418
419 if (files) {
420 task_lock(tsk);
421 tsk->files = NULL;
422 task_unlock(tsk);
423 put_files_struct(files);
424 }
425}
426
427void exit_files(struct task_struct *tsk)
428{
429 __exit_files(tsk);
430}
431
432static inline void __put_fs_struct(struct fs_struct *fs)
433{
434 /* No need to hold fs->lock if we are killing it */
435 if (atomic_dec_and_test(&fs->count)) {
436 dput(fs->root);
437 mntput(fs->rootmnt);
438 dput(fs->pwd);
439 mntput(fs->pwdmnt);
440 if (fs->altroot) {
441 dput(fs->altroot);
442 mntput(fs->altrootmnt);
443 }
444 kmem_cache_free(fs_cachep, fs);
445 }
446}
447
448void put_fs_struct(struct fs_struct *fs)
449{
450 __put_fs_struct(fs);
451}
452
453static inline void __exit_fs(struct task_struct *tsk)
454{
455 struct fs_struct * fs = tsk->fs;
456
457 if (fs) {
458 task_lock(tsk);
459 tsk->fs = NULL;
460 task_unlock(tsk);
461 __put_fs_struct(fs);
462 }
463}
464
465void exit_fs(struct task_struct *tsk)
466{
467 __exit_fs(tsk);
468}
469
470EXPORT_SYMBOL_GPL(exit_fs);
471
472/*
473 * Turn us into a lazy TLB process if we
474 * aren't already..
475 */
476void exit_mm(struct task_struct * tsk)
477{
478 struct mm_struct *mm = tsk->mm;
479
480 mm_release(tsk, mm);
481 if (!mm)
482 return;
483 /*
484 * Serialize with any possible pending coredump.
485 * We must hold mmap_sem around checking core_waiters
486 * and clearing tsk->mm. The core-inducing thread
487 * will increment core_waiters for each thread in the
488 * group with ->mm != NULL.
489 */
490 down_read(&mm->mmap_sem);
491 if (mm->core_waiters) {
492 up_read(&mm->mmap_sem);
493 down_write(&mm->mmap_sem);
494 if (!--mm->core_waiters)
495 complete(mm->core_startup_done);
496 up_write(&mm->mmap_sem);
497
498 wait_for_completion(&mm->core_done);
499 down_read(&mm->mmap_sem);
500 }
501 atomic_inc(&mm->mm_count);
502 if (mm != tsk->active_mm) BUG();
503 /* more a memory barrier than a real lock */
504 task_lock(tsk);
505 tsk->mm = NULL;
506 up_read(&mm->mmap_sem);
507 enter_lazy_tlb(mm, current);
508 task_unlock(tsk);
509 mmput(mm);
510}
511
512static inline void choose_new_parent(task_t *p, task_t *reaper, task_t *child_reaper)
513{
514 /*
515 * Make sure we're not reparenting to ourselves and that
516 * the parent is not a zombie.
517 */
518 BUG_ON(p == reaper || reaper->exit_state >= EXIT_ZOMBIE);
519 p->real_parent = reaper;
520 if (p->parent == p->real_parent)
521 BUG();
522}
523
524static inline void reparent_thread(task_t *p, task_t *father, int traced)
525{
526 /* We don't want people slaying init. */
527 if (p->exit_signal != -1)
528 p->exit_signal = SIGCHLD;
529
530 if (p->pdeath_signal)
531 /* We already hold the tasklist_lock here. */
532 group_send_sig_info(p->pdeath_signal, (void *) 0, p);
533
534 /* Move the child from its dying parent to the new one. */
535 if (unlikely(traced)) {
536 /* Preserve ptrace links if someone else is tracing this child. */
537 list_del_init(&p->ptrace_list);
538 if (p->parent != p->real_parent)
539 list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
540 } else {
541 /* If this child is being traced, then we're the one tracing it
542 * anyway, so let go of it.
543 */
544 p->ptrace = 0;
545 list_del_init(&p->sibling);
546 p->parent = p->real_parent;
547 list_add_tail(&p->sibling, &p->parent->children);
548
549 /* If we'd notified the old parent about this child's death,
550 * also notify the new parent.
551 */
552 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
553 thread_group_empty(p))
554 do_notify_parent(p, p->exit_signal);
555 else if (p->state == TASK_TRACED) {
556 /*
557 * If it was at a trace stop, turn it into
558 * a normal stop since it's no longer being
559 * traced.
560 */
561 ptrace_untrace(p);
562 }
563 }
564
565 /*
566 * process group orphan check
567 * Case ii: Our child is in a different pgrp
568 * than we are, and it was the only connection
569 * outside, so the child pgrp is now orphaned.
570 */
571 if ((process_group(p) != process_group(father)) &&
572 (p->signal->session == father->signal->session)) {
573 int pgrp = process_group(p);
574
575 if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
576 __kill_pg_info(SIGHUP, (void *)1, pgrp);
577 __kill_pg_info(SIGCONT, (void *)1, pgrp);
578 }
579 }
580}
581
582/*
583 * When we die, we re-parent all our children.
584 * Try to give them to another thread in our thread
585 * group, and if no such member exists, give it to
586 * the global child reaper process (ie "init")
587 */
588static inline void forget_original_parent(struct task_struct * father,
589 struct list_head *to_release)
590{
591 struct task_struct *p, *reaper = father;
592 struct list_head *_p, *_n;
593
594 do {
595 reaper = next_thread(reaper);
596 if (reaper == father) {
597 reaper = child_reaper;
598 break;
599 }
600 } while (reaper->exit_state);
601
602 /*
603 * There are only two places where our children can be:
604 *
605 * - in our child list
606 * - in our ptraced child list
607 *
608 * Search them and reparent children.
609 */
610 list_for_each_safe(_p, _n, &father->children) {
611 int ptrace;
612 p = list_entry(_p,struct task_struct,sibling);
613
614 ptrace = p->ptrace;
615
616 /* if father isn't the real parent, then ptrace must be enabled */
617 BUG_ON(father != p->real_parent && !ptrace);
618
619 if (father == p->real_parent) {
620 /* reparent with a reaper, real father it's us */
621 choose_new_parent(p, reaper, child_reaper);
622 reparent_thread(p, father, 0);
623 } else {
624 /* reparent ptraced task to its real parent */
625 __ptrace_unlink (p);
626 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
627 thread_group_empty(p))
628 do_notify_parent(p, p->exit_signal);
629 }
630
631 /*
632 * if the ptraced child is a zombie with exit_signal == -1
633 * we must collect it before we exit, or it will remain
634 * zombie forever since we prevented it from self-reap itself
635 * while it was being traced by us, to be able to see it in wait4.
636 */
637 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
638 list_add(&p->ptrace_list, to_release);
639 }
640 list_for_each_safe(_p, _n, &father->ptrace_children) {
641 p = list_entry(_p,struct task_struct,ptrace_list);
642 choose_new_parent(p, reaper, child_reaper);
643 reparent_thread(p, father, 1);
644 }
645}
646
647/*
648 * Send signals to all our closest relatives so that they know
649 * to properly mourn us..
650 */
651static void exit_notify(struct task_struct *tsk)
652{
653 int state;
654 struct task_struct *t;
655 struct list_head ptrace_dead, *_p, *_n;
656
657 if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
658 && !thread_group_empty(tsk)) {
659 /*
660 * This occurs when there was a race between our exit
661 * syscall and a group signal choosing us as the one to
662 * wake up. It could be that we are the only thread
663 * alerted to check for pending signals, but another thread
664 * should be woken now to take the signal since we will not.
665 * Now we'll wake all the threads in the group just to make
666 * sure someone gets all the pending signals.
667 */
668 read_lock(&tasklist_lock);
669 spin_lock_irq(&tsk->sighand->siglock);
670 for (t = next_thread(tsk); t != tsk; t = next_thread(t))
671 if (!signal_pending(t) && !(t->flags & PF_EXITING)) {
672 recalc_sigpending_tsk(t);
673 if (signal_pending(t))
674 signal_wake_up(t, 0);
675 }
676 spin_unlock_irq(&tsk->sighand->siglock);
677 read_unlock(&tasklist_lock);
678 }
679
680 write_lock_irq(&tasklist_lock);
681
682 /*
683 * This does two things:
684 *
685 * A. Make init inherit all the child processes
686 * B. Check to see if any process groups have become orphaned
687 * as a result of our exiting, and if they have any stopped
688 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
689 */
690
691 INIT_LIST_HEAD(&ptrace_dead);
692 forget_original_parent(tsk, &ptrace_dead);
693 BUG_ON(!list_empty(&tsk->children));
694 BUG_ON(!list_empty(&tsk->ptrace_children));
695
696 /*
697 * Check to see if any process groups have become orphaned
698 * as a result of our exiting, and if they have any stopped
699 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
700 *
701 * Case i: Our father is in a different pgrp than we are
702 * and we were the only connection outside, so our pgrp
703 * is about to become orphaned.
704 */
705
706 t = tsk->real_parent;
707
708 if ((process_group(t) != process_group(tsk)) &&
709 (t->signal->session == tsk->signal->session) &&
710 will_become_orphaned_pgrp(process_group(tsk), tsk) &&
711 has_stopped_jobs(process_group(tsk))) {
712 __kill_pg_info(SIGHUP, (void *)1, process_group(tsk));
713 __kill_pg_info(SIGCONT, (void *)1, process_group(tsk));
714 }
715
716 /* Let father know we died
717 *
718 * Thread signals are configurable, but you aren't going to use
719 * that to send signals to arbitary processes.
720 * That stops right now.
721 *
722 * If the parent exec id doesn't match the exec id we saved
723 * when we started then we know the parent has changed security
724 * domain.
725 *
726 * If our self_exec id doesn't match our parent_exec_id then
727 * we have changed execution domain as these two values started
728 * the same after a fork.
729 *
730 */
731
732 if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
733 ( tsk->parent_exec_id != t->self_exec_id ||
734 tsk->self_exec_id != tsk->parent_exec_id)
735 && !capable(CAP_KILL))
736 tsk->exit_signal = SIGCHLD;
737
738
739 /* If something other than our normal parent is ptracing us, then
740 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
741 * only has special meaning to our real parent.
742 */
743 if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
744 int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
745 do_notify_parent(tsk, signal);
746 } else if (tsk->ptrace) {
747 do_notify_parent(tsk, SIGCHLD);
748 }
749
750 state = EXIT_ZOMBIE;
751 if (tsk->exit_signal == -1 &&
752 (likely(tsk->ptrace == 0) ||
753 unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT)))
754 state = EXIT_DEAD;
755 tsk->exit_state = state;
756
757 write_unlock_irq(&tasklist_lock);
758
759 list_for_each_safe(_p, _n, &ptrace_dead) {
760 list_del_init(_p);
761 t = list_entry(_p,struct task_struct,ptrace_list);
762 release_task(t);
763 }
764
765 /* If the process is dead, release it - nobody will wait for it */
766 if (state == EXIT_DEAD)
767 release_task(tsk);
768
769 /* PF_DEAD causes final put_task_struct after we schedule. */
770 preempt_disable();
771 tsk->flags |= PF_DEAD;
772}
773
774fastcall NORET_TYPE void do_exit(long code)
775{
776 struct task_struct *tsk = current;
777 int group_dead;
778
779 profile_task_exit(tsk);
780
781 if (unlikely(in_interrupt()))
782 panic("Aiee, killing interrupt handler!");
783 if (unlikely(!tsk->pid))
784 panic("Attempted to kill the idle task!");
785 if (unlikely(tsk->pid == 1))
786 panic("Attempted to kill init!");
787 if (tsk->io_context)
788 exit_io_context();
789
790 if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
791 current->ptrace_message = code;
792 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
793 }
794
795 tsk->flags |= PF_EXITING;
796
797 /*
798 * Make sure we don't try to process any timer firings
799 * while we are already exiting.
800 */
801 tsk->it_virt_expires = cputime_zero;
802 tsk->it_prof_expires = cputime_zero;
803 tsk->it_sched_expires = 0;
804
805 if (unlikely(in_atomic()))
806 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
807 current->comm, current->pid,
808 preempt_count());
809
810 acct_update_integrals(tsk);
811 update_mem_hiwater(tsk);
812 group_dead = atomic_dec_and_test(&tsk->signal->live);
813 if (group_dead) {
814 del_timer_sync(&tsk->signal->real_timer);
815 acct_process(code);
816 }
817 exit_mm(tsk);
818
819 exit_sem(tsk);
820 __exit_files(tsk);
821 __exit_fs(tsk);
822 exit_namespace(tsk);
823 exit_thread();
824 cpuset_exit(tsk);
825 exit_keys(tsk);
826
827 if (group_dead && tsk->signal->leader)
828 disassociate_ctty(1);
829
830 module_put(tsk->thread_info->exec_domain->module);
831 if (tsk->binfmt)
832 module_put(tsk->binfmt->module);
833
834 tsk->exit_code = code;
835 exit_notify(tsk);
836#ifdef CONFIG_NUMA
837 mpol_free(tsk->mempolicy);
838 tsk->mempolicy = NULL;
839#endif
840
841 BUG_ON(!(current->flags & PF_DEAD));
842 schedule();
843 BUG();
844 /* Avoid "noreturn function does return". */
845 for (;;) ;
846}
847
848NORET_TYPE void complete_and_exit(struct completion *comp, long code)
849{
850 if (comp)
851 complete(comp);
852
853 do_exit(code);
854}
855
856EXPORT_SYMBOL(complete_and_exit);
857
858asmlinkage long sys_exit(int error_code)
859{
860 do_exit((error_code&0xff)<<8);
861}
862
863task_t fastcall *next_thread(const task_t *p)
864{
865 return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
866}
867
868EXPORT_SYMBOL(next_thread);
869
870/*
871 * Take down every thread in the group. This is called by fatal signals
872 * as well as by sys_exit_group (below).
873 */
874NORET_TYPE void
875do_group_exit(int exit_code)
876{
877 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
878
879 if (current->signal->flags & SIGNAL_GROUP_EXIT)
880 exit_code = current->signal->group_exit_code;
881 else if (!thread_group_empty(current)) {
882 struct signal_struct *const sig = current->signal;
883 struct sighand_struct *const sighand = current->sighand;
884 read_lock(&tasklist_lock);
885 spin_lock_irq(&sighand->siglock);
886 if (sig->flags & SIGNAL_GROUP_EXIT)
887 /* Another thread got here before we took the lock. */
888 exit_code = sig->group_exit_code;
889 else {
890 sig->flags = SIGNAL_GROUP_EXIT;
891 sig->group_exit_code = exit_code;
892 zap_other_threads(current);
893 }
894 spin_unlock_irq(&sighand->siglock);
895 read_unlock(&tasklist_lock);
896 }
897
898 do_exit(exit_code);
899 /* NOTREACHED */
900}
901
902/*
903 * this kills every thread in the thread group. Note that any externally
904 * wait4()-ing process will get the correct exit code - even if this
905 * thread is not the thread group leader.
906 */
907asmlinkage void sys_exit_group(int error_code)
908{
909 do_group_exit((error_code & 0xff) << 8);
910}
911
912static int eligible_child(pid_t pid, int options, task_t *p)
913{
914 if (pid > 0) {
915 if (p->pid != pid)
916 return 0;
917 } else if (!pid) {
918 if (process_group(p) != process_group(current))
919 return 0;
920 } else if (pid != -1) {
921 if (process_group(p) != -pid)
922 return 0;
923 }
924
925 /*
926 * Do not consider detached threads that are
927 * not ptraced:
928 */
929 if (p->exit_signal == -1 && !p->ptrace)
930 return 0;
931
932 /* Wait for all children (clone and not) if __WALL is set;
933 * otherwise, wait for clone children *only* if __WCLONE is
934 * set; otherwise, wait for non-clone children *only*. (Note:
935 * A "clone" child here is one that reports to its parent
936 * using a signal other than SIGCHLD.) */
937 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
938 && !(options & __WALL))
939 return 0;
940 /*
941 * Do not consider thread group leaders that are
942 * in a non-empty thread group:
943 */
944 if (current->tgid != p->tgid && delay_group_leader(p))
945 return 2;
946
947 if (security_task_wait(p))
948 return 0;
949
950 return 1;
951}
952
953static int wait_noreap_copyout(task_t *p, pid_t pid, uid_t uid,
954 int why, int status,
955 struct siginfo __user *infop,
956 struct rusage __user *rusagep)
957{
958 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
959 put_task_struct(p);
960 if (!retval)
961 retval = put_user(SIGCHLD, &infop->si_signo);
962 if (!retval)
963 retval = put_user(0, &infop->si_errno);
964 if (!retval)
965 retval = put_user((short)why, &infop->si_code);
966 if (!retval)
967 retval = put_user(pid, &infop->si_pid);
968 if (!retval)
969 retval = put_user(uid, &infop->si_uid);
970 if (!retval)
971 retval = put_user(status, &infop->si_status);
972 if (!retval)
973 retval = pid;
974 return retval;
975}
976
977/*
978 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
979 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
980 * the lock and this task is uninteresting. If we return nonzero, we have
981 * released the lock and the system call should return.
982 */
983static int wait_task_zombie(task_t *p, int noreap,
984 struct siginfo __user *infop,
985 int __user *stat_addr, struct rusage __user *ru)
986{
987 unsigned long state;
988 int retval;
989 int status;
990
991 if (unlikely(noreap)) {
992 pid_t pid = p->pid;
993 uid_t uid = p->uid;
994 int exit_code = p->exit_code;
995 int why, status;
996
997 if (unlikely(p->exit_state != EXIT_ZOMBIE))
998 return 0;
999 if (unlikely(p->exit_signal == -1 && p->ptrace == 0))
1000 return 0;
1001 get_task_struct(p);
1002 read_unlock(&tasklist_lock);
1003 if ((exit_code & 0x7f) == 0) {
1004 why = CLD_EXITED;
1005 status = exit_code >> 8;
1006 } else {
1007 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1008 status = exit_code & 0x7f;
1009 }
1010 return wait_noreap_copyout(p, pid, uid, why,
1011 status, infop, ru);
1012 }
1013
1014 /*
1015 * Try to move the task's state to DEAD
1016 * only one thread is allowed to do this:
1017 */
1018 state = xchg(&p->exit_state, EXIT_DEAD);
1019 if (state != EXIT_ZOMBIE) {
1020 BUG_ON(state != EXIT_DEAD);
1021 return 0;
1022 }
1023 if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) {
1024 /*
1025 * This can only happen in a race with a ptraced thread
1026 * dying on another processor.
1027 */
1028 return 0;
1029 }
1030
1031 if (likely(p->real_parent == p->parent) && likely(p->signal)) {
1032 /*
1033 * The resource counters for the group leader are in its
1034 * own task_struct. Those for dead threads in the group
1035 * are in its signal_struct, as are those for the child
1036 * processes it has previously reaped. All these
1037 * accumulate in the parent's signal_struct c* fields.
1038 *
1039 * We don't bother to take a lock here to protect these
1040 * p->signal fields, because they are only touched by
1041 * __exit_signal, which runs with tasklist_lock
1042 * write-locked anyway, and so is excluded here. We do
1043 * need to protect the access to p->parent->signal fields,
1044 * as other threads in the parent group can be right
1045 * here reaping other children at the same time.
1046 */
1047 spin_lock_irq(&p->parent->sighand->siglock);
1048 p->parent->signal->cutime =
1049 cputime_add(p->parent->signal->cutime,
1050 cputime_add(p->utime,
1051 cputime_add(p->signal->utime,
1052 p->signal->cutime)));
1053 p->parent->signal->cstime =
1054 cputime_add(p->parent->signal->cstime,
1055 cputime_add(p->stime,
1056 cputime_add(p->signal->stime,
1057 p->signal->cstime)));
1058 p->parent->signal->cmin_flt +=
1059 p->min_flt + p->signal->min_flt + p->signal->cmin_flt;
1060 p->parent->signal->cmaj_flt +=
1061 p->maj_flt + p->signal->maj_flt + p->signal->cmaj_flt;
1062 p->parent->signal->cnvcsw +=
1063 p->nvcsw + p->signal->nvcsw + p->signal->cnvcsw;
1064 p->parent->signal->cnivcsw +=
1065 p->nivcsw + p->signal->nivcsw + p->signal->cnivcsw;
1066 spin_unlock_irq(&p->parent->sighand->siglock);
1067 }
1068
1069 /*
1070 * Now we are sure this task is interesting, and no other
1071 * thread can reap it because we set its state to EXIT_DEAD.
1072 */
1073 read_unlock(&tasklist_lock);
1074
1075 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1076 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1077 ? p->signal->group_exit_code : p->exit_code;
1078 if (!retval && stat_addr)
1079 retval = put_user(status, stat_addr);
1080 if (!retval && infop)
1081 retval = put_user(SIGCHLD, &infop->si_signo);
1082 if (!retval && infop)
1083 retval = put_user(0, &infop->si_errno);
1084 if (!retval && infop) {
1085 int why;
1086
1087 if ((status & 0x7f) == 0) {
1088 why = CLD_EXITED;
1089 status >>= 8;
1090 } else {
1091 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1092 status &= 0x7f;
1093 }
1094 retval = put_user((short)why, &infop->si_code);
1095 if (!retval)
1096 retval = put_user(status, &infop->si_status);
1097 }
1098 if (!retval && infop)
1099 retval = put_user(p->pid, &infop->si_pid);
1100 if (!retval && infop)
1101 retval = put_user(p->uid, &infop->si_uid);
1102 if (retval) {
1103 // TODO: is this safe?
1104 p->exit_state = EXIT_ZOMBIE;
1105 return retval;
1106 }
1107 retval = p->pid;
1108 if (p->real_parent != p->parent) {
1109 write_lock_irq(&tasklist_lock);
1110 /* Double-check with lock held. */
1111 if (p->real_parent != p->parent) {
1112 __ptrace_unlink(p);
1113 // TODO: is this safe?
1114 p->exit_state = EXIT_ZOMBIE;
1115 /*
1116 * If this is not a detached task, notify the parent.
1117 * If it's still not detached after that, don't release
1118 * it now.
1119 */
1120 if (p->exit_signal != -1) {
1121 do_notify_parent(p, p->exit_signal);
1122 if (p->exit_signal != -1)
1123 p = NULL;
1124 }
1125 }
1126 write_unlock_irq(&tasklist_lock);
1127 }
1128 if (p != NULL)
1129 release_task(p);
1130 BUG_ON(!retval);
1131 return retval;
1132}
1133
1134/*
1135 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1136 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1137 * the lock and this task is uninteresting. If we return nonzero, we have
1138 * released the lock and the system call should return.
1139 */
1140static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap,
1141 struct siginfo __user *infop,
1142 int __user *stat_addr, struct rusage __user *ru)
1143{
1144 int retval, exit_code;
1145
1146 if (!p->exit_code)
1147 return 0;
1148 if (delayed_group_leader && !(p->ptrace & PT_PTRACED) &&
1149 p->signal && p->signal->group_stop_count > 0)
1150 /*
1151 * A group stop is in progress and this is the group leader.
1152 * We won't report until all threads have stopped.
1153 */
1154 return 0;
1155
1156 /*
1157 * Now we are pretty sure this task is interesting.
1158 * Make sure it doesn't get reaped out from under us while we
1159 * give up the lock and then examine it below. We don't want to
1160 * keep holding onto the tasklist_lock while we call getrusage and
1161 * possibly take page faults for user memory.
1162 */
1163 get_task_struct(p);
1164 read_unlock(&tasklist_lock);
1165
1166 if (unlikely(noreap)) {
1167 pid_t pid = p->pid;
1168 uid_t uid = p->uid;
1169 int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
1170
1171 exit_code = p->exit_code;
1172 if (unlikely(!exit_code) ||
1173 unlikely(p->state > TASK_STOPPED))
1174 goto bail_ref;
1175 return wait_noreap_copyout(p, pid, uid,
1176 why, (exit_code << 8) | 0x7f,
1177 infop, ru);
1178 }
1179
1180 write_lock_irq(&tasklist_lock);
1181
1182 /*
1183 * This uses xchg to be atomic with the thread resuming and setting
1184 * it. It must also be done with the write lock held to prevent a
1185 * race with the EXIT_ZOMBIE case.
1186 */
1187 exit_code = xchg(&p->exit_code, 0);
1188 if (unlikely(p->exit_state)) {
1189 /*
1190 * The task resumed and then died. Let the next iteration
1191 * catch it in EXIT_ZOMBIE. Note that exit_code might
1192 * already be zero here if it resumed and did _exit(0).
1193 * The task itself is dead and won't touch exit_code again;
1194 * other processors in this function are locked out.
1195 */
1196 p->exit_code = exit_code;
1197 exit_code = 0;
1198 }
1199 if (unlikely(exit_code == 0)) {
1200 /*
1201 * Another thread in this function got to it first, or it
1202 * resumed, or it resumed and then died.
1203 */
1204 write_unlock_irq(&tasklist_lock);
1205bail_ref:
1206 put_task_struct(p);
1207 /*
1208 * We are returning to the wait loop without having successfully
1209 * removed the process and having released the lock. We cannot
1210 * continue, since the "p" task pointer is potentially stale.
1211 *
1212 * Return -EAGAIN, and do_wait() will restart the loop from the
1213 * beginning. Do _not_ re-acquire the lock.
1214 */
1215 return -EAGAIN;
1216 }
1217
1218 /* move to end of parent's list to avoid starvation */
1219 remove_parent(p);
1220 add_parent(p, p->parent);
1221
1222 write_unlock_irq(&tasklist_lock);
1223
1224 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1225 if (!retval && stat_addr)
1226 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1227 if (!retval && infop)
1228 retval = put_user(SIGCHLD, &infop->si_signo);
1229 if (!retval && infop)
1230 retval = put_user(0, &infop->si_errno);
1231 if (!retval && infop)
1232 retval = put_user((short)((p->ptrace & PT_PTRACED)
1233 ? CLD_TRAPPED : CLD_STOPPED),
1234 &infop->si_code);
1235 if (!retval && infop)
1236 retval = put_user(exit_code, &infop->si_status);
1237 if (!retval && infop)
1238 retval = put_user(p->pid, &infop->si_pid);
1239 if (!retval && infop)
1240 retval = put_user(p->uid, &infop->si_uid);
1241 if (!retval)
1242 retval = p->pid;
1243 put_task_struct(p);
1244
1245 BUG_ON(!retval);
1246 return retval;
1247}
1248
1249/*
1250 * Handle do_wait work for one task in a live, non-stopped state.
1251 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1252 * the lock and this task is uninteresting. If we return nonzero, we have
1253 * released the lock and the system call should return.
1254 */
1255static int wait_task_continued(task_t *p, int noreap,
1256 struct siginfo __user *infop,
1257 int __user *stat_addr, struct rusage __user *ru)
1258{
1259 int retval;
1260 pid_t pid;
1261 uid_t uid;
1262
1263 if (unlikely(!p->signal))
1264 return 0;
1265
1266 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1267 return 0;
1268
1269 spin_lock_irq(&p->sighand->siglock);
1270 /* Re-check with the lock held. */
1271 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1272 spin_unlock_irq(&p->sighand->siglock);
1273 return 0;
1274 }
1275 if (!noreap)
1276 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1277 spin_unlock_irq(&p->sighand->siglock);
1278
1279 pid = p->pid;
1280 uid = p->uid;
1281 get_task_struct(p);
1282 read_unlock(&tasklist_lock);
1283
1284 if (!infop) {
1285 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1286 put_task_struct(p);
1287 if (!retval && stat_addr)
1288 retval = put_user(0xffff, stat_addr);
1289 if (!retval)
1290 retval = p->pid;
1291 } else {
1292 retval = wait_noreap_copyout(p, pid, uid,
1293 CLD_CONTINUED, SIGCONT,
1294 infop, ru);
1295 BUG_ON(retval == 0);
1296 }
1297
1298 return retval;
1299}
1300
1301
1302static inline int my_ptrace_child(struct task_struct *p)
1303{
1304 if (!(p->ptrace & PT_PTRACED))
1305 return 0;
1306 if (!(p->ptrace & PT_ATTACHED))
1307 return 1;
1308 /*
1309 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1310 * we are the attacher. If we are the real parent, this is a race
1311 * inside ptrace_attach. It is waiting for the tasklist_lock,
1312 * which we have to switch the parent links, but has already set
1313 * the flags in p->ptrace.
1314 */
1315 return (p->parent != p->real_parent);
1316}
1317
1318static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
1319 int __user *stat_addr, struct rusage __user *ru)
1320{
1321 DECLARE_WAITQUEUE(wait, current);
1322 struct task_struct *tsk;
1323 int flag, retval;
1324
1325 add_wait_queue(&current->signal->wait_chldexit,&wait);
1326repeat:
1327 /*
1328 * We will set this flag if we see any child that might later
1329 * match our criteria, even if we are not able to reap it yet.
1330 */
1331 flag = 0;
1332 current->state = TASK_INTERRUPTIBLE;
1333 read_lock(&tasklist_lock);
1334 tsk = current;
1335 do {
1336 struct task_struct *p;
1337 struct list_head *_p;
1338 int ret;
1339
1340 list_for_each(_p,&tsk->children) {
1341 p = list_entry(_p,struct task_struct,sibling);
1342
1343 ret = eligible_child(pid, options, p);
1344 if (!ret)
1345 continue;
1346
1347 switch (p->state) {
1348 case TASK_TRACED:
1349 if (!my_ptrace_child(p))
1350 continue;
1351 /*FALLTHROUGH*/
1352 case TASK_STOPPED:
1353 /*
1354 * It's stopped now, so it might later
1355 * continue, exit, or stop again.
1356 */
1357 flag = 1;
1358 if (!(options & WUNTRACED) &&
1359 !my_ptrace_child(p))
1360 continue;
1361 retval = wait_task_stopped(p, ret == 2,
1362 (options & WNOWAIT),
1363 infop,
1364 stat_addr, ru);
1365 if (retval == -EAGAIN)
1366 goto repeat;
1367 if (retval != 0) /* He released the lock. */
1368 goto end;
1369 break;
1370 default:
1371 // case EXIT_DEAD:
1372 if (p->exit_state == EXIT_DEAD)
1373 continue;
1374 // case EXIT_ZOMBIE:
1375 if (p->exit_state == EXIT_ZOMBIE) {
1376 /*
1377 * Eligible but we cannot release
1378 * it yet:
1379 */
1380 if (ret == 2)
1381 goto check_continued;
1382 if (!likely(options & WEXITED))
1383 continue;
1384 retval = wait_task_zombie(
1385 p, (options & WNOWAIT),
1386 infop, stat_addr, ru);
1387 /* He released the lock. */
1388 if (retval != 0)
1389 goto end;
1390 break;
1391 }
1392check_continued:
1393 /*
1394 * It's running now, so it might later
1395 * exit, stop, or stop and then continue.
1396 */
1397 flag = 1;
1398 if (!unlikely(options & WCONTINUED))
1399 continue;
1400 retval = wait_task_continued(
1401 p, (options & WNOWAIT),
1402 infop, stat_addr, ru);
1403 if (retval != 0) /* He released the lock. */
1404 goto end;
1405 break;
1406 }
1407 }
1408 if (!flag) {
1409 list_for_each(_p, &tsk->ptrace_children) {
1410 p = list_entry(_p, struct task_struct,
1411 ptrace_list);
1412 if (!eligible_child(pid, options, p))
1413 continue;
1414 flag = 1;
1415 break;
1416 }
1417 }
1418 if (options & __WNOTHREAD)
1419 break;
1420 tsk = next_thread(tsk);
1421 if (tsk->signal != current->signal)
1422 BUG();
1423 } while (tsk != current);
1424
1425 read_unlock(&tasklist_lock);
1426 if (flag) {
1427 retval = 0;
1428 if (options & WNOHANG)
1429 goto end;
1430 retval = -ERESTARTSYS;
1431 if (signal_pending(current))
1432 goto end;
1433 schedule();
1434 goto repeat;
1435 }
1436 retval = -ECHILD;
1437end:
1438 current->state = TASK_RUNNING;
1439 remove_wait_queue(&current->signal->wait_chldexit,&wait);
1440 if (infop) {
1441 if (retval > 0)
1442 retval = 0;
1443 else {
1444 /*
1445 * For a WNOHANG return, clear out all the fields
1446 * we would set so the user can easily tell the
1447 * difference.
1448 */
1449 if (!retval)
1450 retval = put_user(0, &infop->si_signo);
1451 if (!retval)
1452 retval = put_user(0, &infop->si_errno);
1453 if (!retval)
1454 retval = put_user(0, &infop->si_code);
1455 if (!retval)
1456 retval = put_user(0, &infop->si_pid);
1457 if (!retval)
1458 retval = put_user(0, &infop->si_uid);
1459 if (!retval)
1460 retval = put_user(0, &infop->si_status);
1461 }
1462 }
1463 return retval;
1464}
1465
1466asmlinkage long sys_waitid(int which, pid_t pid,
1467 struct siginfo __user *infop, int options,
1468 struct rusage __user *ru)
1469{
1470 long ret;
1471
1472 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1473 return -EINVAL;
1474 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1475 return -EINVAL;
1476
1477 switch (which) {
1478 case P_ALL:
1479 pid = -1;
1480 break;
1481 case P_PID:
1482 if (pid <= 0)
1483 return -EINVAL;
1484 break;
1485 case P_PGID:
1486 if (pid <= 0)
1487 return -EINVAL;
1488 pid = -pid;
1489 break;
1490 default:
1491 return -EINVAL;
1492 }
1493
1494 ret = do_wait(pid, options, infop, NULL, ru);
1495
1496 /* avoid REGPARM breakage on x86: */
1497 prevent_tail_call(ret);
1498 return ret;
1499}
1500
1501asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
1502 int options, struct rusage __user *ru)
1503{
1504 long ret;
1505
1506 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1507 __WNOTHREAD|__WCLONE|__WALL))
1508 return -EINVAL;
1509 ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru);
1510
1511 /* avoid REGPARM breakage on x86: */
1512 prevent_tail_call(ret);
1513 return ret;
1514}
1515
1516#ifdef __ARCH_WANT_SYS_WAITPID
1517
1518/*
1519 * sys_waitpid() remains for compatibility. waitpid() should be
1520 * implemented by calling sys_wait4() from libc.a.
1521 */
1522asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
1523{
1524 return sys_wait4(pid, stat_addr, options, NULL);
1525}
1526
1527#endif