blob: 7be283d98983d8cebc6f7853ab3ef233185e7532 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070030#include <linux/signal.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32#include <asm/uaccess.h>
33#include <asm/unistd.h>
34#include <asm/pgtable.h>
35#include <asm/mmu_context.h>
36
37extern void sem_exit (void);
38extern struct task_struct *child_reaper;
39
40int getrusage(struct task_struct *, int, struct rusage __user *);
41
Adrian Bunk408b6642005-05-01 08:59:29 -070042static void exit_mm(struct task_struct * tsk);
43
Linus Torvalds1da177e2005-04-16 15:20:36 -070044static void __unhash_process(struct task_struct *p)
45{
46 nr_threads--;
47 detach_pid(p, PIDTYPE_PID);
48 detach_pid(p, PIDTYPE_TGID);
49 if (thread_group_leader(p)) {
50 detach_pid(p, PIDTYPE_PGID);
51 detach_pid(p, PIDTYPE_SID);
52 if (p->pid)
53 __get_cpu_var(process_counts)--;
54 }
55
56 REMOVE_LINKS(p);
57}
58
59void release_task(struct task_struct * p)
60{
61 int zap_leader;
62 task_t *leader;
63 struct dentry *proc_dentry;
64
65repeat:
66 atomic_dec(&p->user->processes);
67 spin_lock(&p->proc_lock);
68 proc_dentry = proc_pid_unhash(p);
69 write_lock_irq(&tasklist_lock);
70 if (unlikely(p->ptrace))
71 __ptrace_unlink(p);
72 BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
73 __exit_signal(p);
74 __exit_sighand(p);
75 __unhash_process(p);
76
77 /*
78 * If we are the last non-leader member of the thread
79 * group, and the leader is zombie, then notify the
80 * group leader's parent process. (if it wants notification.)
81 */
82 zap_leader = 0;
83 leader = p->group_leader;
84 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
85 BUG_ON(leader->exit_signal == -1);
86 do_notify_parent(leader, leader->exit_signal);
87 /*
88 * If we were the last child thread and the leader has
89 * exited already, and the leader's parent ignores SIGCHLD,
90 * then we are the one who should release the leader.
91 *
92 * do_notify_parent() will have marked it self-reaping in
93 * that case.
94 */
95 zap_leader = (leader->exit_signal == -1);
96 }
97
98 sched_exit(p);
99 write_unlock_irq(&tasklist_lock);
100 spin_unlock(&p->proc_lock);
101 proc_pid_flush(proc_dentry);
102 release_thread(p);
103 put_task_struct(p);
104
105 p = leader;
106 if (unlikely(zap_leader))
107 goto repeat;
108}
109
110/* we are using it only for SMP init */
111
112void unhash_process(struct task_struct *p)
113{
114 struct dentry *proc_dentry;
115
116 spin_lock(&p->proc_lock);
117 proc_dentry = proc_pid_unhash(p);
118 write_lock_irq(&tasklist_lock);
119 __unhash_process(p);
120 write_unlock_irq(&tasklist_lock);
121 spin_unlock(&p->proc_lock);
122 proc_pid_flush(proc_dentry);
123}
124
125/*
126 * This checks not only the pgrp, but falls back on the pid if no
127 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
128 * without this...
129 */
130int session_of_pgrp(int pgrp)
131{
132 struct task_struct *p;
133 int sid = -1;
134
135 read_lock(&tasklist_lock);
136 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
137 if (p->signal->session > 0) {
138 sid = p->signal->session;
139 goto out;
140 }
141 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
142 p = find_task_by_pid(pgrp);
143 if (p)
144 sid = p->signal->session;
145out:
146 read_unlock(&tasklist_lock);
147
148 return sid;
149}
150
151/*
152 * Determine if a process group is "orphaned", according to the POSIX
153 * definition in 2.2.2.52. Orphaned process groups are not to be affected
154 * by terminal-generated stop signals. Newly orphaned process groups are
155 * to receive a SIGHUP and a SIGCONT.
156 *
157 * "I ask you, have you ever known what it is to be an orphan?"
158 */
159static int will_become_orphaned_pgrp(int pgrp, task_t *ignored_task)
160{
161 struct task_struct *p;
162 int ret = 1;
163
164 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
165 if (p == ignored_task
166 || p->exit_state
167 || p->real_parent->pid == 1)
168 continue;
169 if (process_group(p->real_parent) != pgrp
170 && p->real_parent->signal->session == p->signal->session) {
171 ret = 0;
172 break;
173 }
174 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
175 return ret; /* (sighing) "Often!" */
176}
177
178int is_orphaned_pgrp(int pgrp)
179{
180 int retval;
181
182 read_lock(&tasklist_lock);
183 retval = will_become_orphaned_pgrp(pgrp, NULL);
184 read_unlock(&tasklist_lock);
185
186 return retval;
187}
188
189static inline int has_stopped_jobs(int pgrp)
190{
191 int retval = 0;
192 struct task_struct *p;
193
194 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
195 if (p->state != TASK_STOPPED)
196 continue;
197
198 /* If p is stopped by a debugger on a signal that won't
199 stop it, then don't count p as stopped. This isn't
200 perfect but it's a good approximation. */
201 if (unlikely (p->ptrace)
202 && p->exit_code != SIGSTOP
203 && p->exit_code != SIGTSTP
204 && p->exit_code != SIGTTOU
205 && p->exit_code != SIGTTIN)
206 continue;
207
208 retval = 1;
209 break;
210 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
211 return retval;
212}
213
214/**
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700215 * reparent_to_init - Reparent the calling kernel thread to the init task.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 *
217 * If a kernel thread is launched as a result of a system call, or if
218 * it ever exits, it should generally reparent itself to init so that
219 * it is correctly cleaned up on exit.
220 *
221 * The various task state such as scheduling policy and priority may have
222 * been inherited from a user process, so we reset them to sane values here.
223 *
224 * NOTE that reparent_to_init() gives the caller full capabilities.
225 */
Coywolf Qi Hunt6c46ada2005-04-16 15:26:01 -0700226static inline void reparent_to_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227{
228 write_lock_irq(&tasklist_lock);
229
230 ptrace_unlink(current);
231 /* Reparent to init */
232 REMOVE_LINKS(current);
233 current->parent = child_reaper;
234 current->real_parent = child_reaper;
235 SET_LINKS(current);
236
237 /* Set the exit signal to SIGCHLD so we signal init on exit */
238 current->exit_signal = SIGCHLD;
239
240 if ((current->policy == SCHED_NORMAL) && (task_nice(current) < 0))
241 set_user_nice(current, 0);
242 /* cpus_allowed? */
243 /* rt_priority? */
244 /* signals? */
245 security_task_reparent_to_init(current);
246 memcpy(current->signal->rlim, init_task.signal->rlim,
247 sizeof(current->signal->rlim));
248 atomic_inc(&(INIT_USER->__count));
249 write_unlock_irq(&tasklist_lock);
250 switch_uid(INIT_USER);
251}
252
253void __set_special_pids(pid_t session, pid_t pgrp)
254{
255 struct task_struct *curr = current;
256
257 if (curr->signal->session != session) {
258 detach_pid(curr, PIDTYPE_SID);
259 curr->signal->session = session;
260 attach_pid(curr, PIDTYPE_SID, session);
261 }
262 if (process_group(curr) != pgrp) {
263 detach_pid(curr, PIDTYPE_PGID);
264 curr->signal->pgrp = pgrp;
265 attach_pid(curr, PIDTYPE_PGID, pgrp);
266 }
267}
268
269void set_special_pids(pid_t session, pid_t pgrp)
270{
271 write_lock_irq(&tasklist_lock);
272 __set_special_pids(session, pgrp);
273 write_unlock_irq(&tasklist_lock);
274}
275
276/*
277 * Let kernel threads use this to say that they
278 * allow a certain signal (since daemonize() will
279 * have disabled all of them by default).
280 */
281int allow_signal(int sig)
282{
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700283 if (!valid_signal(sig) || sig < 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 return -EINVAL;
285
286 spin_lock_irq(&current->sighand->siglock);
287 sigdelset(&current->blocked, sig);
288 if (!current->mm) {
289 /* Kernel threads handle their own signals.
290 Let the signal code know it'll be handled, so
291 that they don't get converted to SIGKILL or
292 just silently dropped */
293 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
294 }
295 recalc_sigpending();
296 spin_unlock_irq(&current->sighand->siglock);
297 return 0;
298}
299
300EXPORT_SYMBOL(allow_signal);
301
302int disallow_signal(int sig)
303{
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700304 if (!valid_signal(sig) || sig < 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 return -EINVAL;
306
307 spin_lock_irq(&current->sighand->siglock);
308 sigaddset(&current->blocked, sig);
309 recalc_sigpending();
310 spin_unlock_irq(&current->sighand->siglock);
311 return 0;
312}
313
314EXPORT_SYMBOL(disallow_signal);
315
316/*
317 * Put all the gunge required to become a kernel thread without
318 * attached user resources in one place where it belongs.
319 */
320
321void daemonize(const char *name, ...)
322{
323 va_list args;
324 struct fs_struct *fs;
325 sigset_t blocked;
326
327 va_start(args, name);
328 vsnprintf(current->comm, sizeof(current->comm), name, args);
329 va_end(args);
330
331 /*
332 * If we were started as result of loading a module, close all of the
333 * user space pages. We don't need them, and if we didn't close them
334 * they would be locked into memory.
335 */
336 exit_mm(current);
337
338 set_special_pids(1, 1);
339 down(&tty_sem);
340 current->signal->tty = NULL;
341 up(&tty_sem);
342
343 /* Block and flush all signals */
344 sigfillset(&blocked);
345 sigprocmask(SIG_BLOCK, &blocked, NULL);
346 flush_signals(current);
347
348 /* Become as one with the init task */
349
350 exit_fs(current); /* current->fs->count--; */
351 fs = init_task.fs;
352 current->fs = fs;
353 atomic_inc(&fs->count);
354 exit_files(current);
355 current->files = init_task.files;
356 atomic_inc(&current->files->count);
357
358 reparent_to_init();
359}
360
361EXPORT_SYMBOL(daemonize);
362
363static inline void close_files(struct files_struct * files)
364{
365 int i, j;
366
367 j = 0;
368 for (;;) {
369 unsigned long set;
370 i = j * __NFDBITS;
371 if (i >= files->max_fdset || i >= files->max_fds)
372 break;
373 set = files->open_fds->fds_bits[j++];
374 while (set) {
375 if (set & 1) {
376 struct file * file = xchg(&files->fd[i], NULL);
377 if (file)
378 filp_close(file, files);
379 }
380 i++;
381 set >>= 1;
382 }
383 }
384}
385
386struct files_struct *get_files_struct(struct task_struct *task)
387{
388 struct files_struct *files;
389
390 task_lock(task);
391 files = task->files;
392 if (files)
393 atomic_inc(&files->count);
394 task_unlock(task);
395
396 return files;
397}
398
399void fastcall put_files_struct(struct files_struct *files)
400{
401 if (atomic_dec_and_test(&files->count)) {
402 close_files(files);
403 /*
404 * Free the fd and fdset arrays if we expanded them.
405 */
406 if (files->fd != &files->fd_array[0])
407 free_fd_array(files->fd, files->max_fds);
408 if (files->max_fdset > __FD_SETSIZE) {
409 free_fdset(files->open_fds, files->max_fdset);
410 free_fdset(files->close_on_exec, files->max_fdset);
411 }
412 kmem_cache_free(files_cachep, files);
413 }
414}
415
416EXPORT_SYMBOL(put_files_struct);
417
418static inline void __exit_files(struct task_struct *tsk)
419{
420 struct files_struct * files = tsk->files;
421
422 if (files) {
423 task_lock(tsk);
424 tsk->files = NULL;
425 task_unlock(tsk);
426 put_files_struct(files);
427 }
428}
429
430void exit_files(struct task_struct *tsk)
431{
432 __exit_files(tsk);
433}
434
435static inline void __put_fs_struct(struct fs_struct *fs)
436{
437 /* No need to hold fs->lock if we are killing it */
438 if (atomic_dec_and_test(&fs->count)) {
439 dput(fs->root);
440 mntput(fs->rootmnt);
441 dput(fs->pwd);
442 mntput(fs->pwdmnt);
443 if (fs->altroot) {
444 dput(fs->altroot);
445 mntput(fs->altrootmnt);
446 }
447 kmem_cache_free(fs_cachep, fs);
448 }
449}
450
451void put_fs_struct(struct fs_struct *fs)
452{
453 __put_fs_struct(fs);
454}
455
456static inline void __exit_fs(struct task_struct *tsk)
457{
458 struct fs_struct * fs = tsk->fs;
459
460 if (fs) {
461 task_lock(tsk);
462 tsk->fs = NULL;
463 task_unlock(tsk);
464 __put_fs_struct(fs);
465 }
466}
467
468void exit_fs(struct task_struct *tsk)
469{
470 __exit_fs(tsk);
471}
472
473EXPORT_SYMBOL_GPL(exit_fs);
474
475/*
476 * Turn us into a lazy TLB process if we
477 * aren't already..
478 */
Adrian Bunk408b6642005-05-01 08:59:29 -0700479static void exit_mm(struct task_struct * tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480{
481 struct mm_struct *mm = tsk->mm;
482
483 mm_release(tsk, mm);
484 if (!mm)
485 return;
486 /*
487 * Serialize with any possible pending coredump.
488 * We must hold mmap_sem around checking core_waiters
489 * and clearing tsk->mm. The core-inducing thread
490 * will increment core_waiters for each thread in the
491 * group with ->mm != NULL.
492 */
493 down_read(&mm->mmap_sem);
494 if (mm->core_waiters) {
495 up_read(&mm->mmap_sem);
496 down_write(&mm->mmap_sem);
497 if (!--mm->core_waiters)
498 complete(mm->core_startup_done);
499 up_write(&mm->mmap_sem);
500
501 wait_for_completion(&mm->core_done);
502 down_read(&mm->mmap_sem);
503 }
504 atomic_inc(&mm->mm_count);
505 if (mm != tsk->active_mm) BUG();
506 /* more a memory barrier than a real lock */
507 task_lock(tsk);
508 tsk->mm = NULL;
509 up_read(&mm->mmap_sem);
510 enter_lazy_tlb(mm, current);
511 task_unlock(tsk);
512 mmput(mm);
513}
514
515static inline void choose_new_parent(task_t *p, task_t *reaper, task_t *child_reaper)
516{
517 /*
518 * Make sure we're not reparenting to ourselves and that
519 * the parent is not a zombie.
520 */
521 BUG_ON(p == reaper || reaper->exit_state >= EXIT_ZOMBIE);
522 p->real_parent = reaper;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523}
524
525static inline void reparent_thread(task_t *p, task_t *father, int traced)
526{
527 /* We don't want people slaying init. */
528 if (p->exit_signal != -1)
529 p->exit_signal = SIGCHLD;
530
531 if (p->pdeath_signal)
532 /* We already hold the tasklist_lock here. */
533 group_send_sig_info(p->pdeath_signal, (void *) 0, p);
534
535 /* Move the child from its dying parent to the new one. */
536 if (unlikely(traced)) {
537 /* Preserve ptrace links if someone else is tracing this child. */
538 list_del_init(&p->ptrace_list);
539 if (p->parent != p->real_parent)
540 list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
541 } else {
542 /* If this child is being traced, then we're the one tracing it
543 * anyway, so let go of it.
544 */
545 p->ptrace = 0;
546 list_del_init(&p->sibling);
547 p->parent = p->real_parent;
548 list_add_tail(&p->sibling, &p->parent->children);
549
550 /* If we'd notified the old parent about this child's death,
551 * also notify the new parent.
552 */
553 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
554 thread_group_empty(p))
555 do_notify_parent(p, p->exit_signal);
556 else if (p->state == TASK_TRACED) {
557 /*
558 * If it was at a trace stop, turn it into
559 * a normal stop since it's no longer being
560 * traced.
561 */
562 ptrace_untrace(p);
563 }
564 }
565
566 /*
567 * process group orphan check
568 * Case ii: Our child is in a different pgrp
569 * than we are, and it was the only connection
570 * outside, so the child pgrp is now orphaned.
571 */
572 if ((process_group(p) != process_group(father)) &&
573 (p->signal->session == father->signal->session)) {
574 int pgrp = process_group(p);
575
576 if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
577 __kill_pg_info(SIGHUP, (void *)1, pgrp);
578 __kill_pg_info(SIGCONT, (void *)1, pgrp);
579 }
580 }
581}
582
583/*
584 * When we die, we re-parent all our children.
585 * Try to give them to another thread in our thread
586 * group, and if no such member exists, give it to
587 * the global child reaper process (ie "init")
588 */
589static inline void forget_original_parent(struct task_struct * father,
590 struct list_head *to_release)
591{
592 struct task_struct *p, *reaper = father;
593 struct list_head *_p, *_n;
594
595 do {
596 reaper = next_thread(reaper);
597 if (reaper == father) {
598 reaper = child_reaper;
599 break;
600 }
601 } while (reaper->exit_state);
602
603 /*
604 * There are only two places where our children can be:
605 *
606 * - in our child list
607 * - in our ptraced child list
608 *
609 * Search them and reparent children.
610 */
611 list_for_each_safe(_p, _n, &father->children) {
612 int ptrace;
613 p = list_entry(_p,struct task_struct,sibling);
614
615 ptrace = p->ptrace;
616
617 /* if father isn't the real parent, then ptrace must be enabled */
618 BUG_ON(father != p->real_parent && !ptrace);
619
620 if (father == p->real_parent) {
621 /* reparent with a reaper, real father it's us */
622 choose_new_parent(p, reaper, child_reaper);
623 reparent_thread(p, father, 0);
624 } else {
625 /* reparent ptraced task to its real parent */
626 __ptrace_unlink (p);
627 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
628 thread_group_empty(p))
629 do_notify_parent(p, p->exit_signal);
630 }
631
632 /*
633 * if the ptraced child is a zombie with exit_signal == -1
634 * we must collect it before we exit, or it will remain
635 * zombie forever since we prevented it from self-reap itself
636 * while it was being traced by us, to be able to see it in wait4.
637 */
638 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
639 list_add(&p->ptrace_list, to_release);
640 }
641 list_for_each_safe(_p, _n, &father->ptrace_children) {
642 p = list_entry(_p,struct task_struct,ptrace_list);
643 choose_new_parent(p, reaper, child_reaper);
644 reparent_thread(p, father, 1);
645 }
646}
647
648/*
649 * Send signals to all our closest relatives so that they know
650 * to properly mourn us..
651 */
652static void exit_notify(struct task_struct *tsk)
653{
654 int state;
655 struct task_struct *t;
656 struct list_head ptrace_dead, *_p, *_n;
657
658 if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
659 && !thread_group_empty(tsk)) {
660 /*
661 * This occurs when there was a race between our exit
662 * syscall and a group signal choosing us as the one to
663 * wake up. It could be that we are the only thread
664 * alerted to check for pending signals, but another thread
665 * should be woken now to take the signal since we will not.
666 * Now we'll wake all the threads in the group just to make
667 * sure someone gets all the pending signals.
668 */
669 read_lock(&tasklist_lock);
670 spin_lock_irq(&tsk->sighand->siglock);
671 for (t = next_thread(tsk); t != tsk; t = next_thread(t))
672 if (!signal_pending(t) && !(t->flags & PF_EXITING)) {
673 recalc_sigpending_tsk(t);
674 if (signal_pending(t))
675 signal_wake_up(t, 0);
676 }
677 spin_unlock_irq(&tsk->sighand->siglock);
678 read_unlock(&tasklist_lock);
679 }
680
681 write_lock_irq(&tasklist_lock);
682
683 /*
684 * This does two things:
685 *
686 * A. Make init inherit all the child processes
687 * B. Check to see if any process groups have become orphaned
688 * as a result of our exiting, and if they have any stopped
689 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
690 */
691
692 INIT_LIST_HEAD(&ptrace_dead);
693 forget_original_parent(tsk, &ptrace_dead);
694 BUG_ON(!list_empty(&tsk->children));
695 BUG_ON(!list_empty(&tsk->ptrace_children));
696
697 /*
698 * Check to see if any process groups have become orphaned
699 * as a result of our exiting, and if they have any stopped
700 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
701 *
702 * Case i: Our father is in a different pgrp than we are
703 * and we were the only connection outside, so our pgrp
704 * is about to become orphaned.
705 */
706
707 t = tsk->real_parent;
708
709 if ((process_group(t) != process_group(tsk)) &&
710 (t->signal->session == tsk->signal->session) &&
711 will_become_orphaned_pgrp(process_group(tsk), tsk) &&
712 has_stopped_jobs(process_group(tsk))) {
713 __kill_pg_info(SIGHUP, (void *)1, process_group(tsk));
714 __kill_pg_info(SIGCONT, (void *)1, process_group(tsk));
715 }
716
717 /* Let father know we died
718 *
719 * Thread signals are configurable, but you aren't going to use
720 * that to send signals to arbitary processes.
721 * That stops right now.
722 *
723 * If the parent exec id doesn't match the exec id we saved
724 * when we started then we know the parent has changed security
725 * domain.
726 *
727 * If our self_exec id doesn't match our parent_exec_id then
728 * we have changed execution domain as these two values started
729 * the same after a fork.
730 *
731 */
732
733 if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
734 ( tsk->parent_exec_id != t->self_exec_id ||
735 tsk->self_exec_id != tsk->parent_exec_id)
736 && !capable(CAP_KILL))
737 tsk->exit_signal = SIGCHLD;
738
739
740 /* If something other than our normal parent is ptracing us, then
741 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
742 * only has special meaning to our real parent.
743 */
744 if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
745 int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
746 do_notify_parent(tsk, signal);
747 } else if (tsk->ptrace) {
748 do_notify_parent(tsk, SIGCHLD);
749 }
750
751 state = EXIT_ZOMBIE;
752 if (tsk->exit_signal == -1 &&
753 (likely(tsk->ptrace == 0) ||
754 unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT)))
755 state = EXIT_DEAD;
756 tsk->exit_state = state;
757
758 write_unlock_irq(&tasklist_lock);
759
760 list_for_each_safe(_p, _n, &ptrace_dead) {
761 list_del_init(_p);
762 t = list_entry(_p,struct task_struct,ptrace_list);
763 release_task(t);
764 }
765
766 /* If the process is dead, release it - nobody will wait for it */
767 if (state == EXIT_DEAD)
768 release_task(tsk);
769
770 /* PF_DEAD causes final put_task_struct after we schedule. */
771 preempt_disable();
772 tsk->flags |= PF_DEAD;
773}
774
775fastcall NORET_TYPE void do_exit(long code)
776{
777 struct task_struct *tsk = current;
778 int group_dead;
779
780 profile_task_exit(tsk);
781
782 if (unlikely(in_interrupt()))
783 panic("Aiee, killing interrupt handler!");
784 if (unlikely(!tsk->pid))
785 panic("Attempted to kill the idle task!");
786 if (unlikely(tsk->pid == 1))
787 panic("Attempted to kill init!");
788 if (tsk->io_context)
789 exit_io_context();
790
791 if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
792 current->ptrace_message = code;
793 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
794 }
795
796 tsk->flags |= PF_EXITING;
797
798 /*
799 * Make sure we don't try to process any timer firings
800 * while we are already exiting.
801 */
802 tsk->it_virt_expires = cputime_zero;
803 tsk->it_prof_expires = cputime_zero;
804 tsk->it_sched_expires = 0;
805
806 if (unlikely(in_atomic()))
807 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
808 current->comm, current->pid,
809 preempt_count());
810
811 acct_update_integrals(tsk);
812 update_mem_hiwater(tsk);
813 group_dead = atomic_dec_and_test(&tsk->signal->live);
814 if (group_dead) {
815 del_timer_sync(&tsk->signal->real_timer);
816 acct_process(code);
817 }
818 exit_mm(tsk);
819
820 exit_sem(tsk);
821 __exit_files(tsk);
822 __exit_fs(tsk);
823 exit_namespace(tsk);
824 exit_thread();
825 cpuset_exit(tsk);
826 exit_keys(tsk);
827
828 if (group_dead && tsk->signal->leader)
829 disassociate_ctty(1);
830
831 module_put(tsk->thread_info->exec_domain->module);
832 if (tsk->binfmt)
833 module_put(tsk->binfmt->module);
834
835 tsk->exit_code = code;
836 exit_notify(tsk);
837#ifdef CONFIG_NUMA
838 mpol_free(tsk->mempolicy);
839 tsk->mempolicy = NULL;
840#endif
841
842 BUG_ON(!(current->flags & PF_DEAD));
843 schedule();
844 BUG();
845 /* Avoid "noreturn function does return". */
846 for (;;) ;
847}
848
849NORET_TYPE void complete_and_exit(struct completion *comp, long code)
850{
851 if (comp)
852 complete(comp);
853
854 do_exit(code);
855}
856
857EXPORT_SYMBOL(complete_and_exit);
858
859asmlinkage long sys_exit(int error_code)
860{
861 do_exit((error_code&0xff)<<8);
862}
863
864task_t fastcall *next_thread(const task_t *p)
865{
866 return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
867}
868
869EXPORT_SYMBOL(next_thread);
870
871/*
872 * Take down every thread in the group. This is called by fatal signals
873 * as well as by sys_exit_group (below).
874 */
875NORET_TYPE void
876do_group_exit(int exit_code)
877{
878 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
879
880 if (current->signal->flags & SIGNAL_GROUP_EXIT)
881 exit_code = current->signal->group_exit_code;
882 else if (!thread_group_empty(current)) {
883 struct signal_struct *const sig = current->signal;
884 struct sighand_struct *const sighand = current->sighand;
885 read_lock(&tasklist_lock);
886 spin_lock_irq(&sighand->siglock);
887 if (sig->flags & SIGNAL_GROUP_EXIT)
888 /* Another thread got here before we took the lock. */
889 exit_code = sig->group_exit_code;
890 else {
891 sig->flags = SIGNAL_GROUP_EXIT;
892 sig->group_exit_code = exit_code;
893 zap_other_threads(current);
894 }
895 spin_unlock_irq(&sighand->siglock);
896 read_unlock(&tasklist_lock);
897 }
898
899 do_exit(exit_code);
900 /* NOTREACHED */
901}
902
903/*
904 * this kills every thread in the thread group. Note that any externally
905 * wait4()-ing process will get the correct exit code - even if this
906 * thread is not the thread group leader.
907 */
908asmlinkage void sys_exit_group(int error_code)
909{
910 do_group_exit((error_code & 0xff) << 8);
911}
912
913static int eligible_child(pid_t pid, int options, task_t *p)
914{
915 if (pid > 0) {
916 if (p->pid != pid)
917 return 0;
918 } else if (!pid) {
919 if (process_group(p) != process_group(current))
920 return 0;
921 } else if (pid != -1) {
922 if (process_group(p) != -pid)
923 return 0;
924 }
925
926 /*
927 * Do not consider detached threads that are
928 * not ptraced:
929 */
930 if (p->exit_signal == -1 && !p->ptrace)
931 return 0;
932
933 /* Wait for all children (clone and not) if __WALL is set;
934 * otherwise, wait for clone children *only* if __WCLONE is
935 * set; otherwise, wait for non-clone children *only*. (Note:
936 * A "clone" child here is one that reports to its parent
937 * using a signal other than SIGCHLD.) */
938 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
939 && !(options & __WALL))
940 return 0;
941 /*
942 * Do not consider thread group leaders that are
943 * in a non-empty thread group:
944 */
945 if (current->tgid != p->tgid && delay_group_leader(p))
946 return 2;
947
948 if (security_task_wait(p))
949 return 0;
950
951 return 1;
952}
953
954static int wait_noreap_copyout(task_t *p, pid_t pid, uid_t uid,
955 int why, int status,
956 struct siginfo __user *infop,
957 struct rusage __user *rusagep)
958{
959 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
960 put_task_struct(p);
961 if (!retval)
962 retval = put_user(SIGCHLD, &infop->si_signo);
963 if (!retval)
964 retval = put_user(0, &infop->si_errno);
965 if (!retval)
966 retval = put_user((short)why, &infop->si_code);
967 if (!retval)
968 retval = put_user(pid, &infop->si_pid);
969 if (!retval)
970 retval = put_user(uid, &infop->si_uid);
971 if (!retval)
972 retval = put_user(status, &infop->si_status);
973 if (!retval)
974 retval = pid;
975 return retval;
976}
977
978/*
979 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
980 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
981 * the lock and this task is uninteresting. If we return nonzero, we have
982 * released the lock and the system call should return.
983 */
984static int wait_task_zombie(task_t *p, int noreap,
985 struct siginfo __user *infop,
986 int __user *stat_addr, struct rusage __user *ru)
987{
988 unsigned long state;
989 int retval;
990 int status;
991
992 if (unlikely(noreap)) {
993 pid_t pid = p->pid;
994 uid_t uid = p->uid;
995 int exit_code = p->exit_code;
996 int why, status;
997
998 if (unlikely(p->exit_state != EXIT_ZOMBIE))
999 return 0;
1000 if (unlikely(p->exit_signal == -1 && p->ptrace == 0))
1001 return 0;
1002 get_task_struct(p);
1003 read_unlock(&tasklist_lock);
1004 if ((exit_code & 0x7f) == 0) {
1005 why = CLD_EXITED;
1006 status = exit_code >> 8;
1007 } else {
1008 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1009 status = exit_code & 0x7f;
1010 }
1011 return wait_noreap_copyout(p, pid, uid, why,
1012 status, infop, ru);
1013 }
1014
1015 /*
1016 * Try to move the task's state to DEAD
1017 * only one thread is allowed to do this:
1018 */
1019 state = xchg(&p->exit_state, EXIT_DEAD);
1020 if (state != EXIT_ZOMBIE) {
1021 BUG_ON(state != EXIT_DEAD);
1022 return 0;
1023 }
1024 if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) {
1025 /*
1026 * This can only happen in a race with a ptraced thread
1027 * dying on another processor.
1028 */
1029 return 0;
1030 }
1031
1032 if (likely(p->real_parent == p->parent) && likely(p->signal)) {
1033 /*
1034 * The resource counters for the group leader are in its
1035 * own task_struct. Those for dead threads in the group
1036 * are in its signal_struct, as are those for the child
1037 * processes it has previously reaped. All these
1038 * accumulate in the parent's signal_struct c* fields.
1039 *
1040 * We don't bother to take a lock here to protect these
1041 * p->signal fields, because they are only touched by
1042 * __exit_signal, which runs with tasklist_lock
1043 * write-locked anyway, and so is excluded here. We do
1044 * need to protect the access to p->parent->signal fields,
1045 * as other threads in the parent group can be right
1046 * here reaping other children at the same time.
1047 */
1048 spin_lock_irq(&p->parent->sighand->siglock);
1049 p->parent->signal->cutime =
1050 cputime_add(p->parent->signal->cutime,
1051 cputime_add(p->utime,
1052 cputime_add(p->signal->utime,
1053 p->signal->cutime)));
1054 p->parent->signal->cstime =
1055 cputime_add(p->parent->signal->cstime,
1056 cputime_add(p->stime,
1057 cputime_add(p->signal->stime,
1058 p->signal->cstime)));
1059 p->parent->signal->cmin_flt +=
1060 p->min_flt + p->signal->min_flt + p->signal->cmin_flt;
1061 p->parent->signal->cmaj_flt +=
1062 p->maj_flt + p->signal->maj_flt + p->signal->cmaj_flt;
1063 p->parent->signal->cnvcsw +=
1064 p->nvcsw + p->signal->nvcsw + p->signal->cnvcsw;
1065 p->parent->signal->cnivcsw +=
1066 p->nivcsw + p->signal->nivcsw + p->signal->cnivcsw;
1067 spin_unlock_irq(&p->parent->sighand->siglock);
1068 }
1069
1070 /*
1071 * Now we are sure this task is interesting, and no other
1072 * thread can reap it because we set its state to EXIT_DEAD.
1073 */
1074 read_unlock(&tasklist_lock);
1075
1076 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1077 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1078 ? p->signal->group_exit_code : p->exit_code;
1079 if (!retval && stat_addr)
1080 retval = put_user(status, stat_addr);
1081 if (!retval && infop)
1082 retval = put_user(SIGCHLD, &infop->si_signo);
1083 if (!retval && infop)
1084 retval = put_user(0, &infop->si_errno);
1085 if (!retval && infop) {
1086 int why;
1087
1088 if ((status & 0x7f) == 0) {
1089 why = CLD_EXITED;
1090 status >>= 8;
1091 } else {
1092 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1093 status &= 0x7f;
1094 }
1095 retval = put_user((short)why, &infop->si_code);
1096 if (!retval)
1097 retval = put_user(status, &infop->si_status);
1098 }
1099 if (!retval && infop)
1100 retval = put_user(p->pid, &infop->si_pid);
1101 if (!retval && infop)
1102 retval = put_user(p->uid, &infop->si_uid);
1103 if (retval) {
1104 // TODO: is this safe?
1105 p->exit_state = EXIT_ZOMBIE;
1106 return retval;
1107 }
1108 retval = p->pid;
1109 if (p->real_parent != p->parent) {
1110 write_lock_irq(&tasklist_lock);
1111 /* Double-check with lock held. */
1112 if (p->real_parent != p->parent) {
1113 __ptrace_unlink(p);
1114 // TODO: is this safe?
1115 p->exit_state = EXIT_ZOMBIE;
1116 /*
1117 * If this is not a detached task, notify the parent.
1118 * If it's still not detached after that, don't release
1119 * it now.
1120 */
1121 if (p->exit_signal != -1) {
1122 do_notify_parent(p, p->exit_signal);
1123 if (p->exit_signal != -1)
1124 p = NULL;
1125 }
1126 }
1127 write_unlock_irq(&tasklist_lock);
1128 }
1129 if (p != NULL)
1130 release_task(p);
1131 BUG_ON(!retval);
1132 return retval;
1133}
1134
1135/*
1136 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1137 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1138 * the lock and this task is uninteresting. If we return nonzero, we have
1139 * released the lock and the system call should return.
1140 */
1141static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap,
1142 struct siginfo __user *infop,
1143 int __user *stat_addr, struct rusage __user *ru)
1144{
1145 int retval, exit_code;
1146
1147 if (!p->exit_code)
1148 return 0;
1149 if (delayed_group_leader && !(p->ptrace & PT_PTRACED) &&
1150 p->signal && p->signal->group_stop_count > 0)
1151 /*
1152 * A group stop is in progress and this is the group leader.
1153 * We won't report until all threads have stopped.
1154 */
1155 return 0;
1156
1157 /*
1158 * Now we are pretty sure this task is interesting.
1159 * Make sure it doesn't get reaped out from under us while we
1160 * give up the lock and then examine it below. We don't want to
1161 * keep holding onto the tasklist_lock while we call getrusage and
1162 * possibly take page faults for user memory.
1163 */
1164 get_task_struct(p);
1165 read_unlock(&tasklist_lock);
1166
1167 if (unlikely(noreap)) {
1168 pid_t pid = p->pid;
1169 uid_t uid = p->uid;
1170 int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
1171
1172 exit_code = p->exit_code;
1173 if (unlikely(!exit_code) ||
1174 unlikely(p->state > TASK_STOPPED))
1175 goto bail_ref;
1176 return wait_noreap_copyout(p, pid, uid,
1177 why, (exit_code << 8) | 0x7f,
1178 infop, ru);
1179 }
1180
1181 write_lock_irq(&tasklist_lock);
1182
1183 /*
1184 * This uses xchg to be atomic with the thread resuming and setting
1185 * it. It must also be done with the write lock held to prevent a
1186 * race with the EXIT_ZOMBIE case.
1187 */
1188 exit_code = xchg(&p->exit_code, 0);
1189 if (unlikely(p->exit_state)) {
1190 /*
1191 * The task resumed and then died. Let the next iteration
1192 * catch it in EXIT_ZOMBIE. Note that exit_code might
1193 * already be zero here if it resumed and did _exit(0).
1194 * The task itself is dead and won't touch exit_code again;
1195 * other processors in this function are locked out.
1196 */
1197 p->exit_code = exit_code;
1198 exit_code = 0;
1199 }
1200 if (unlikely(exit_code == 0)) {
1201 /*
1202 * Another thread in this function got to it first, or it
1203 * resumed, or it resumed and then died.
1204 */
1205 write_unlock_irq(&tasklist_lock);
1206bail_ref:
1207 put_task_struct(p);
1208 /*
1209 * We are returning to the wait loop without having successfully
1210 * removed the process and having released the lock. We cannot
1211 * continue, since the "p" task pointer is potentially stale.
1212 *
1213 * Return -EAGAIN, and do_wait() will restart the loop from the
1214 * beginning. Do _not_ re-acquire the lock.
1215 */
1216 return -EAGAIN;
1217 }
1218
1219 /* move to end of parent's list to avoid starvation */
1220 remove_parent(p);
1221 add_parent(p, p->parent);
1222
1223 write_unlock_irq(&tasklist_lock);
1224
1225 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1226 if (!retval && stat_addr)
1227 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1228 if (!retval && infop)
1229 retval = put_user(SIGCHLD, &infop->si_signo);
1230 if (!retval && infop)
1231 retval = put_user(0, &infop->si_errno);
1232 if (!retval && infop)
1233 retval = put_user((short)((p->ptrace & PT_PTRACED)
1234 ? CLD_TRAPPED : CLD_STOPPED),
1235 &infop->si_code);
1236 if (!retval && infop)
1237 retval = put_user(exit_code, &infop->si_status);
1238 if (!retval && infop)
1239 retval = put_user(p->pid, &infop->si_pid);
1240 if (!retval && infop)
1241 retval = put_user(p->uid, &infop->si_uid);
1242 if (!retval)
1243 retval = p->pid;
1244 put_task_struct(p);
1245
1246 BUG_ON(!retval);
1247 return retval;
1248}
1249
1250/*
1251 * Handle do_wait work for one task in a live, non-stopped state.
1252 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1253 * the lock and this task is uninteresting. If we return nonzero, we have
1254 * released the lock and the system call should return.
1255 */
1256static int wait_task_continued(task_t *p, int noreap,
1257 struct siginfo __user *infop,
1258 int __user *stat_addr, struct rusage __user *ru)
1259{
1260 int retval;
1261 pid_t pid;
1262 uid_t uid;
1263
1264 if (unlikely(!p->signal))
1265 return 0;
1266
1267 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1268 return 0;
1269
1270 spin_lock_irq(&p->sighand->siglock);
1271 /* Re-check with the lock held. */
1272 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1273 spin_unlock_irq(&p->sighand->siglock);
1274 return 0;
1275 }
1276 if (!noreap)
1277 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1278 spin_unlock_irq(&p->sighand->siglock);
1279
1280 pid = p->pid;
1281 uid = p->uid;
1282 get_task_struct(p);
1283 read_unlock(&tasklist_lock);
1284
1285 if (!infop) {
1286 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1287 put_task_struct(p);
1288 if (!retval && stat_addr)
1289 retval = put_user(0xffff, stat_addr);
1290 if (!retval)
1291 retval = p->pid;
1292 } else {
1293 retval = wait_noreap_copyout(p, pid, uid,
1294 CLD_CONTINUED, SIGCONT,
1295 infop, ru);
1296 BUG_ON(retval == 0);
1297 }
1298
1299 return retval;
1300}
1301
1302
1303static inline int my_ptrace_child(struct task_struct *p)
1304{
1305 if (!(p->ptrace & PT_PTRACED))
1306 return 0;
1307 if (!(p->ptrace & PT_ATTACHED))
1308 return 1;
1309 /*
1310 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1311 * we are the attacher. If we are the real parent, this is a race
1312 * inside ptrace_attach. It is waiting for the tasklist_lock,
1313 * which we have to switch the parent links, but has already set
1314 * the flags in p->ptrace.
1315 */
1316 return (p->parent != p->real_parent);
1317}
1318
1319static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
1320 int __user *stat_addr, struct rusage __user *ru)
1321{
1322 DECLARE_WAITQUEUE(wait, current);
1323 struct task_struct *tsk;
1324 int flag, retval;
1325
1326 add_wait_queue(&current->signal->wait_chldexit,&wait);
1327repeat:
1328 /*
1329 * We will set this flag if we see any child that might later
1330 * match our criteria, even if we are not able to reap it yet.
1331 */
1332 flag = 0;
1333 current->state = TASK_INTERRUPTIBLE;
1334 read_lock(&tasklist_lock);
1335 tsk = current;
1336 do {
1337 struct task_struct *p;
1338 struct list_head *_p;
1339 int ret;
1340
1341 list_for_each(_p,&tsk->children) {
1342 p = list_entry(_p,struct task_struct,sibling);
1343
1344 ret = eligible_child(pid, options, p);
1345 if (!ret)
1346 continue;
1347
1348 switch (p->state) {
1349 case TASK_TRACED:
1350 if (!my_ptrace_child(p))
1351 continue;
1352 /*FALLTHROUGH*/
1353 case TASK_STOPPED:
1354 /*
1355 * It's stopped now, so it might later
1356 * continue, exit, or stop again.
1357 */
1358 flag = 1;
1359 if (!(options & WUNTRACED) &&
1360 !my_ptrace_child(p))
1361 continue;
1362 retval = wait_task_stopped(p, ret == 2,
1363 (options & WNOWAIT),
1364 infop,
1365 stat_addr, ru);
1366 if (retval == -EAGAIN)
1367 goto repeat;
1368 if (retval != 0) /* He released the lock. */
1369 goto end;
1370 break;
1371 default:
1372 // case EXIT_DEAD:
1373 if (p->exit_state == EXIT_DEAD)
1374 continue;
1375 // case EXIT_ZOMBIE:
1376 if (p->exit_state == EXIT_ZOMBIE) {
1377 /*
1378 * Eligible but we cannot release
1379 * it yet:
1380 */
1381 if (ret == 2)
1382 goto check_continued;
1383 if (!likely(options & WEXITED))
1384 continue;
1385 retval = wait_task_zombie(
1386 p, (options & WNOWAIT),
1387 infop, stat_addr, ru);
1388 /* He released the lock. */
1389 if (retval != 0)
1390 goto end;
1391 break;
1392 }
1393check_continued:
1394 /*
1395 * It's running now, so it might later
1396 * exit, stop, or stop and then continue.
1397 */
1398 flag = 1;
1399 if (!unlikely(options & WCONTINUED))
1400 continue;
1401 retval = wait_task_continued(
1402 p, (options & WNOWAIT),
1403 infop, stat_addr, ru);
1404 if (retval != 0) /* He released the lock. */
1405 goto end;
1406 break;
1407 }
1408 }
1409 if (!flag) {
1410 list_for_each(_p, &tsk->ptrace_children) {
1411 p = list_entry(_p, struct task_struct,
1412 ptrace_list);
1413 if (!eligible_child(pid, options, p))
1414 continue;
1415 flag = 1;
1416 break;
1417 }
1418 }
1419 if (options & __WNOTHREAD)
1420 break;
1421 tsk = next_thread(tsk);
1422 if (tsk->signal != current->signal)
1423 BUG();
1424 } while (tsk != current);
1425
1426 read_unlock(&tasklist_lock);
1427 if (flag) {
1428 retval = 0;
1429 if (options & WNOHANG)
1430 goto end;
1431 retval = -ERESTARTSYS;
1432 if (signal_pending(current))
1433 goto end;
1434 schedule();
1435 goto repeat;
1436 }
1437 retval = -ECHILD;
1438end:
1439 current->state = TASK_RUNNING;
1440 remove_wait_queue(&current->signal->wait_chldexit,&wait);
1441 if (infop) {
1442 if (retval > 0)
1443 retval = 0;
1444 else {
1445 /*
1446 * For a WNOHANG return, clear out all the fields
1447 * we would set so the user can easily tell the
1448 * difference.
1449 */
1450 if (!retval)
1451 retval = put_user(0, &infop->si_signo);
1452 if (!retval)
1453 retval = put_user(0, &infop->si_errno);
1454 if (!retval)
1455 retval = put_user(0, &infop->si_code);
1456 if (!retval)
1457 retval = put_user(0, &infop->si_pid);
1458 if (!retval)
1459 retval = put_user(0, &infop->si_uid);
1460 if (!retval)
1461 retval = put_user(0, &infop->si_status);
1462 }
1463 }
1464 return retval;
1465}
1466
1467asmlinkage long sys_waitid(int which, pid_t pid,
1468 struct siginfo __user *infop, int options,
1469 struct rusage __user *ru)
1470{
1471 long ret;
1472
1473 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1474 return -EINVAL;
1475 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1476 return -EINVAL;
1477
1478 switch (which) {
1479 case P_ALL:
1480 pid = -1;
1481 break;
1482 case P_PID:
1483 if (pid <= 0)
1484 return -EINVAL;
1485 break;
1486 case P_PGID:
1487 if (pid <= 0)
1488 return -EINVAL;
1489 pid = -pid;
1490 break;
1491 default:
1492 return -EINVAL;
1493 }
1494
1495 ret = do_wait(pid, options, infop, NULL, ru);
1496
1497 /* avoid REGPARM breakage on x86: */
1498 prevent_tail_call(ret);
1499 return ret;
1500}
1501
1502asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
1503 int options, struct rusage __user *ru)
1504{
1505 long ret;
1506
1507 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1508 __WNOTHREAD|__WCLONE|__WALL))
1509 return -EINVAL;
1510 ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru);
1511
1512 /* avoid REGPARM breakage on x86: */
1513 prevent_tail_call(ret);
1514 return ret;
1515}
1516
1517#ifdef __ARCH_WANT_SYS_WAITPID
1518
1519/*
1520 * sys_waitpid() remains for compatibility. waitpid() should be
1521 * implemented by calling sys_wait4() from libc.a.
1522 */
1523asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
1524{
1525 return sys_wait4(pid, stat_addr, options, NULL);
1526}
1527
1528#endif