4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/config.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/capability.h>
14 #include <linux/completion.h>
15 #include <linux/personality.h>
16 #include <linux/tty.h>
17 #include <linux/namespace.h>
18 #include <linux/key.h>
19 #include <linux/security.h>
20 #include <linux/cpu.h>
21 #include <linux/acct.h>
22 #include <linux/file.h>
23 #include <linux/binfmts.h>
24 #include <linux/ptrace.h>
25 #include <linux/profile.h>
26 #include <linux/mount.h>
27 #include <linux/proc_fs.h>
28 #include <linux/mempolicy.h>
29 #include <linux/cpuset.h>
30 #include <linux/syscalls.h>
31 #include <linux/signal.h>
32 #include <linux/cn_proc.h>
33 #include <linux/mutex.h>
34 #include <linux/vs_limit.h>
35 #include <linux/vs_context.h>
36 #include <linux/vs_network.h>
37 #include <linux/vs_cvirt.h>
39 #include <asm/uaccess.h>
40 #include <asm/unistd.h>
41 #include <asm/pgtable.h>
42 #include <asm/mmu_context.h>
44 extern void sem_exit (void);
45 extern struct task_struct *child_reaper;
47 int getrusage(struct task_struct *, int, struct rusage __user *);
49 static void exit_mm(struct task_struct * tsk);
51 static void __unhash_process(struct task_struct *p)
54 detach_pid(p, PIDTYPE_PID);
55 detach_pid(p, PIDTYPE_TGID);
56 if (thread_group_leader(p)) {
57 detach_pid(p, PIDTYPE_PGID);
58 detach_pid(p, PIDTYPE_SID);
60 __get_cpu_var(process_counts)--;
66 void release_task(struct task_struct * p)
70 struct dentry *proc_dentry;
73 atomic_dec(&p->user->processes);
74 spin_lock(&p->proc_lock);
75 proc_dentry = proc_pid_unhash(p);
76 write_lock_irq(&tasklist_lock);
77 if (unlikely(p->ptrace))
79 BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
82 * Note that the fastpath in sys_times depends on __exit_signal having
83 * updated the counters before a task is removed from the tasklist of
84 * the process by __unhash_process.
89 * If we are the last non-leader member of the thread
90 * group, and the leader is zombie, then notify the
91 * group leader's parent process. (if it wants notification.)
94 leader = p->group_leader;
95 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
96 BUG_ON(leader->exit_signal == -1);
97 do_notify_parent(leader, leader->exit_signal);
99 * If we were the last child thread and the leader has
100 * exited already, and the leader's parent ignores SIGCHLD,
101 * then we are the one who should release the leader.
103 * do_notify_parent() will have marked it self-reaping in
106 zap_leader = (leader->exit_signal == -1);
110 write_unlock_irq(&tasklist_lock);
111 spin_unlock(&p->proc_lock);
112 proc_pid_flush(proc_dentry);
117 if (unlikely(zap_leader))
121 /* we are using it only for SMP init */
123 void unhash_process(struct task_struct *p)
125 struct dentry *proc_dentry;
127 spin_lock(&p->proc_lock);
128 proc_dentry = proc_pid_unhash(p);
129 write_lock_irq(&tasklist_lock);
131 write_unlock_irq(&tasklist_lock);
132 spin_unlock(&p->proc_lock);
133 proc_pid_flush(proc_dentry);
137 * This checks not only the pgrp, but falls back on the pid if no
138 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
141 int session_of_pgrp(int pgrp)
143 struct task_struct *p;
146 read_lock(&tasklist_lock);
147 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
148 if (p->signal->session > 0) {
149 sid = p->signal->session;
152 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
153 p = find_task_by_pid(pgrp);
155 sid = p->signal->session;
157 read_unlock(&tasklist_lock);
163 * Determine if a process group is "orphaned", according to the POSIX
164 * definition in 2.2.2.52. Orphaned process groups are not to be affected
165 * by terminal-generated stop signals. Newly orphaned process groups are
166 * to receive a SIGHUP and a SIGCONT.
168 * "I ask you, have you ever known what it is to be an orphan?"
170 static int will_become_orphaned_pgrp(int pgrp, task_t *ignored_task)
172 struct task_struct *p;
175 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
176 if (p == ignored_task
178 || p->real_parent->pid == 1)
180 if (process_group(p->real_parent) != pgrp
181 && p->real_parent->signal->session == p->signal->session) {
185 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
186 return ret; /* (sighing) "Often!" */
189 int is_orphaned_pgrp(int pgrp)
193 read_lock(&tasklist_lock);
194 retval = will_become_orphaned_pgrp(pgrp, NULL);
195 read_unlock(&tasklist_lock);
200 static int has_stopped_jobs(int pgrp)
203 struct task_struct *p;
205 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
206 if (p->state != TASK_STOPPED)
209 /* If p is stopped by a debugger on a signal that won't
210 stop it, then don't count p as stopped. This isn't
211 perfect but it's a good approximation. */
212 if (unlikely (p->ptrace)
213 && p->exit_code != SIGSTOP
214 && p->exit_code != SIGTSTP
215 && p->exit_code != SIGTTOU
216 && p->exit_code != SIGTTIN)
221 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
226 * reparent_to_init - Reparent the calling kernel thread to the init task.
228 * If a kernel thread is launched as a result of a system call, or if
229 * it ever exits, it should generally reparent itself to init so that
230 * it is correctly cleaned up on exit.
232 * The various task state such as scheduling policy and priority may have
233 * been inherited from a user process, so we reset them to sane values here.
235 * NOTE that reparent_to_init() gives the caller full capabilities.
237 static void reparent_to_init(void)
239 write_lock_irq(&tasklist_lock);
241 ptrace_unlink(current);
242 /* Reparent to init */
243 REMOVE_LINKS(current);
244 current->parent = child_reaper;
245 current->real_parent = child_reaper;
248 /* Set the exit signal to SIGCHLD so we signal init on exit */
249 current->exit_signal = SIGCHLD;
251 if ((current->policy == SCHED_NORMAL ||
252 current->policy == SCHED_BATCH)
253 && (task_nice(current) < 0))
254 set_user_nice(current, 0);
258 security_task_reparent_to_init(current);
259 memcpy(current->signal->rlim, init_task.signal->rlim,
260 sizeof(current->signal->rlim));
261 atomic_inc(&(INIT_USER->__count));
262 write_unlock_irq(&tasklist_lock);
263 switch_uid(INIT_USER);
266 void __set_special_pids(pid_t session, pid_t pgrp)
268 struct task_struct *curr = current->group_leader;
270 if (curr->signal->session != session) {
271 detach_pid(curr, PIDTYPE_SID);
272 curr->signal->session = session;
273 attach_pid(curr, PIDTYPE_SID, session);
275 if (process_group(curr) != pgrp) {
276 detach_pid(curr, PIDTYPE_PGID);
277 curr->signal->pgrp = pgrp;
278 attach_pid(curr, PIDTYPE_PGID, pgrp);
282 void set_special_pids(pid_t session, pid_t pgrp)
284 write_lock_irq(&tasklist_lock);
285 __set_special_pids(session, pgrp);
286 write_unlock_irq(&tasklist_lock);
290 * Let kernel threads use this to say that they
291 * allow a certain signal (since daemonize() will
292 * have disabled all of them by default).
294 int allow_signal(int sig)
296 if (!valid_signal(sig) || sig < 1)
299 spin_lock_irq(¤t->sighand->siglock);
300 sigdelset(¤t->blocked, sig);
302 /* Kernel threads handle their own signals.
303 Let the signal code know it'll be handled, so
304 that they don't get converted to SIGKILL or
305 just silently dropped */
306 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
309 spin_unlock_irq(¤t->sighand->siglock);
313 EXPORT_SYMBOL(allow_signal);
315 int disallow_signal(int sig)
317 if (!valid_signal(sig) || sig < 1)
320 spin_lock_irq(¤t->sighand->siglock);
321 sigaddset(¤t->blocked, sig);
323 spin_unlock_irq(¤t->sighand->siglock);
327 EXPORT_SYMBOL(disallow_signal);
330 * Put all the gunge required to become a kernel thread without
331 * attached user resources in one place where it belongs.
334 void daemonize(const char *name, ...)
337 struct fs_struct *fs;
340 va_start(args, name);
341 vsnprintf(current->comm, sizeof(current->comm), name, args);
345 * If we were started as result of loading a module, close all of the
346 * user space pages. We don't need them, and if we didn't close them
347 * they would be locked into memory.
351 set_special_pids(1, 1);
353 current->signal->tty = NULL;
356 /* Block and flush all signals */
357 sigfillset(&blocked);
358 sigprocmask(SIG_BLOCK, &blocked, NULL);
359 flush_signals(current);
361 /* Become as one with the init task */
363 exit_fs(current); /* current->fs->count--; */
366 atomic_inc(&fs->count);
367 exit_namespace(current);
368 current->namespace = init_task.namespace;
369 get_namespace(current->namespace);
371 current->files = init_task.files;
372 atomic_inc(¤t->files->count);
377 EXPORT_SYMBOL(daemonize);
379 static void close_files(struct files_struct * files)
387 * It is safe to dereference the fd table without RCU or
388 * ->file_lock because this is the last reference to the
391 fdt = files_fdtable(files);
395 if (i >= fdt->max_fdset || i >= fdt->max_fds)
397 set = fdt->open_fds->fds_bits[j++];
400 struct file * file = xchg(&fdt->fd[i], NULL);
402 filp_close(file, files);
411 struct files_struct *get_files_struct(struct task_struct *task)
413 struct files_struct *files;
418 atomic_inc(&files->count);
424 void fastcall put_files_struct(struct files_struct *files)
428 if (atomic_dec_and_test(&files->count)) {
431 * Free the fd and fdset arrays if we expanded them.
432 * If the fdtable was embedded, pass files for freeing
433 * at the end of the RCU grace period. Otherwise,
434 * you can free files immediately.
436 fdt = files_fdtable(files);
437 if (fdt == &files->fdtab)
438 fdt->free_files = files;
440 kmem_cache_free(files_cachep, files);
445 EXPORT_SYMBOL(put_files_struct);
447 static inline void __exit_files(struct task_struct *tsk)
449 struct files_struct * files = tsk->files;
455 put_files_struct(files);
459 void exit_files(struct task_struct *tsk)
464 static inline void __put_fs_struct(struct fs_struct *fs)
466 /* No need to hold fs->lock if we are killing it */
467 if (atomic_dec_and_test(&fs->count)) {
474 mntput(fs->altrootmnt);
476 kmem_cache_free(fs_cachep, fs);
480 void put_fs_struct(struct fs_struct *fs)
485 static inline void __exit_fs(struct task_struct *tsk)
487 struct fs_struct * fs = tsk->fs;
497 void exit_fs(struct task_struct *tsk)
502 EXPORT_SYMBOL_GPL(exit_fs);
505 * Turn us into a lazy TLB process if we
508 static void exit_mm(struct task_struct * tsk)
510 struct mm_struct *mm = tsk->mm;
516 * Serialize with any possible pending coredump.
517 * We must hold mmap_sem around checking core_waiters
518 * and clearing tsk->mm. The core-inducing thread
519 * will increment core_waiters for each thread in the
520 * group with ->mm != NULL.
522 down_read(&mm->mmap_sem);
523 if (mm->core_waiters) {
524 up_read(&mm->mmap_sem);
525 down_write(&mm->mmap_sem);
526 if (!--mm->core_waiters)
527 complete(mm->core_startup_done);
528 up_write(&mm->mmap_sem);
530 wait_for_completion(&mm->core_done);
531 down_read(&mm->mmap_sem);
533 atomic_inc(&mm->mm_count);
534 if (mm != tsk->active_mm) BUG();
535 /* more a memory barrier than a real lock */
538 up_read(&mm->mmap_sem);
539 enter_lazy_tlb(mm, current);
544 static inline void choose_new_parent(task_t *p, task_t *reaper)
546 /* check for reaper context */
547 vxwprintk((p->xid != reaper->xid) && (reaper != child_reaper),
548 "rogue reaper: %p[%d,#%u] <> %p[%d,#%u]",
549 p, p->pid, p->xid, reaper, reaper->pid, reaper->xid);
552 * Make sure we're not reparenting to ourselves and that
553 * the parent is not a zombie.
555 BUG_ON(p == reaper || reaper->exit_state >= EXIT_ZOMBIE);
556 p->real_parent = reaper;
559 static void reparent_thread(task_t *p, task_t *father, int traced)
561 /* We don't want people slaying init. */
562 if (p->exit_signal != -1)
563 p->exit_signal = SIGCHLD;
565 if (p->pdeath_signal)
566 /* We already hold the tasklist_lock here. */
567 group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
569 /* Move the child from its dying parent to the new one. */
570 if (unlikely(traced)) {
571 /* Preserve ptrace links if someone else is tracing this child. */
572 list_del_init(&p->ptrace_list);
573 if (p->parent != p->real_parent)
574 list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
576 /* If this child is being traced, then we're the one tracing it
577 * anyway, so let go of it.
580 list_del_init(&p->sibling);
581 p->parent = p->real_parent;
582 list_add_tail(&p->sibling, &p->parent->children);
584 /* If we'd notified the old parent about this child's death,
585 * also notify the new parent.
587 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
588 thread_group_empty(p))
589 do_notify_parent(p, p->exit_signal);
590 else if (p->state == TASK_TRACED) {
592 * If it was at a trace stop, turn it into
593 * a normal stop since it's no longer being
601 * process group orphan check
602 * Case ii: Our child is in a different pgrp
603 * than we are, and it was the only connection
604 * outside, so the child pgrp is now orphaned.
606 if ((process_group(p) != process_group(father)) &&
607 (p->signal->session == father->signal->session)) {
608 int pgrp = process_group(p);
610 if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
611 __kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp);
612 __kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp);
618 * When we die, we re-parent all our children.
619 * Try to give them to another thread in our thread
620 * group, and if no such member exists, give it to
621 * the global child reaper process (ie "init")
623 static void forget_original_parent(struct task_struct * father,
624 struct list_head *to_release)
626 struct task_struct *p, *reaper = father;
627 struct list_head *_p, *_n;
630 reaper = next_thread(reaper);
631 if (reaper == father) {
632 reaper = vx_child_reaper(father);
635 } while (reaper->exit_state);
638 * There are only two places where our children can be:
640 * - in our child list
641 * - in our ptraced child list
643 * Search them and reparent children.
645 list_for_each_safe(_p, _n, &father->children) {
647 p = list_entry(_p,struct task_struct,sibling);
651 /* if father isn't the real parent, then ptrace must be enabled */
652 BUG_ON(father != p->real_parent && !ptrace);
654 if (father == p->real_parent) {
655 /* reparent with a reaper, real father it's us */
656 choose_new_parent(p, vx_child_reaper(p));
657 reparent_thread(p, father, 0);
659 /* reparent ptraced task to its real parent */
661 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
662 thread_group_empty(p))
663 do_notify_parent(p, p->exit_signal);
667 * if the ptraced child is a zombie with exit_signal == -1
668 * we must collect it before we exit, or it will remain
669 * zombie forever since we prevented it from self-reap itself
670 * while it was being traced by us, to be able to see it in wait4.
672 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
673 list_add(&p->ptrace_list, to_release);
675 list_for_each_safe(_p, _n, &father->ptrace_children) {
676 p = list_entry(_p,struct task_struct,ptrace_list);
678 choose_new_parent(p, reaper);
679 reparent_thread(p, father, 1);
684 * Send signals to all our closest relatives so that they know
685 * to properly mourn us..
687 static void exit_notify(struct task_struct *tsk)
690 struct task_struct *t;
691 struct list_head ptrace_dead, *_p, *_n;
693 if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
694 && !thread_group_empty(tsk)) {
696 * This occurs when there was a race between our exit
697 * syscall and a group signal choosing us as the one to
698 * wake up. It could be that we are the only thread
699 * alerted to check for pending signals, but another thread
700 * should be woken now to take the signal since we will not.
701 * Now we'll wake all the threads in the group just to make
702 * sure someone gets all the pending signals.
704 read_lock(&tasklist_lock);
705 spin_lock_irq(&tsk->sighand->siglock);
706 for (t = next_thread(tsk); t != tsk; t = next_thread(t))
707 if (!signal_pending(t) && !(t->flags & PF_EXITING)) {
708 recalc_sigpending_tsk(t);
709 if (signal_pending(t))
710 signal_wake_up(t, 0);
712 spin_unlock_irq(&tsk->sighand->siglock);
713 read_unlock(&tasklist_lock);
716 write_lock_irq(&tasklist_lock);
719 * This does two things:
721 * A. Make init inherit all the child processes
722 * B. Check to see if any process groups have become orphaned
723 * as a result of our exiting, and if they have any stopped
724 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
727 INIT_LIST_HEAD(&ptrace_dead);
728 forget_original_parent(tsk, &ptrace_dead);
729 BUG_ON(!list_empty(&tsk->children));
730 BUG_ON(!list_empty(&tsk->ptrace_children));
733 * Check to see if any process groups have become orphaned
734 * as a result of our exiting, and if they have any stopped
735 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
737 * Case i: Our father is in a different pgrp than we are
738 * and we were the only connection outside, so our pgrp
739 * is about to become orphaned.
742 t = tsk->real_parent;
744 if ((process_group(t) != process_group(tsk)) &&
745 (t->signal->session == tsk->signal->session) &&
746 will_become_orphaned_pgrp(process_group(tsk), tsk) &&
747 has_stopped_jobs(process_group(tsk))) {
748 __kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk));
749 __kill_pg_info(SIGCONT, SEND_SIG_PRIV, process_group(tsk));
752 /* Let father know we died
754 * Thread signals are configurable, but you aren't going to use
755 * that to send signals to arbitary processes.
756 * That stops right now.
758 * If the parent exec id doesn't match the exec id we saved
759 * when we started then we know the parent has changed security
762 * If our self_exec id doesn't match our parent_exec_id then
763 * we have changed execution domain as these two values started
764 * the same after a fork.
768 if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
769 ( tsk->parent_exec_id != t->self_exec_id ||
770 tsk->self_exec_id != tsk->parent_exec_id)
771 && !capable(CAP_KILL))
772 tsk->exit_signal = SIGCHLD;
775 /* If something other than our normal parent is ptracing us, then
776 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
777 * only has special meaning to our real parent.
779 if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
780 int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
781 do_notify_parent(tsk, signal);
782 } else if (tsk->ptrace) {
783 do_notify_parent(tsk, SIGCHLD);
787 if (tsk->exit_signal == -1 &&
788 (likely(tsk->ptrace == 0) ||
789 unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT)))
791 tsk->exit_state = state;
793 write_unlock_irq(&tasklist_lock);
795 list_for_each_safe(_p, _n, &ptrace_dead) {
797 t = list_entry(_p,struct task_struct,ptrace_list);
801 /* If the process is dead, release it - nobody will wait for it */
802 if (state == EXIT_DEAD)
806 fastcall NORET_TYPE void do_exit(long code)
808 struct task_struct *tsk = current;
811 profile_task_exit(tsk);
813 WARN_ON(atomic_read(&tsk->fs_excl));
815 if (unlikely(in_interrupt()))
816 panic("Aiee, killing interrupt handler!");
817 if (unlikely(!tsk->pid))
818 panic("Attempted to kill the idle task!");
819 if (unlikely(tsk->pid == 1))
820 panic("Attempted to kill init!");
824 if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
825 current->ptrace_message = code;
826 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
830 * We're taking recursive faults here in do_exit. Safest is to just
831 * leave this task alone and wait for reboot.
833 if (unlikely(tsk->flags & PF_EXITING)) {
835 "Fixing recursive fault but reboot is needed!\n");
836 set_current_state(TASK_UNINTERRUPTIBLE);
840 tsk->flags |= PF_EXITING;
842 if (unlikely(in_atomic()))
843 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
844 current->comm, current->pid,
847 acct_update_integrals(tsk);
849 update_hiwater_rss(tsk->mm);
850 update_hiwater_vm(tsk->mm);
852 group_dead = atomic_dec_and_test(&tsk->signal->live);
854 hrtimer_cancel(&tsk->signal->real_timer);
855 exit_itimers(tsk->signal);
868 if (group_dead && tsk->signal->leader)
869 disassociate_ctty(1);
871 module_put(task_thread_info(tsk)->exec_domain->module);
873 module_put(tsk->binfmt->module);
875 tsk->exit_code = code;
876 proc_exit_connector(tsk);
877 /* needs to stay before exit_notify() */
878 exit_vx_info_early(tsk, code);
881 mpol_free(tsk->mempolicy);
882 tsk->mempolicy = NULL;
885 * If DEBUG_MUTEXES is on, make sure we are holding no locks:
887 mutex_debug_check_no_locks_held(tsk);
889 /* needs to stay after exit_notify() */
890 exit_vx_info(tsk, code);
893 /* PF_DEAD causes final put_task_struct after we schedule. */
895 BUG_ON(tsk->flags & PF_DEAD);
896 tsk->flags |= PF_DEAD;
900 /* Avoid "noreturn function does return". */
904 EXPORT_SYMBOL_GPL(do_exit);
906 NORET_TYPE void complete_and_exit(struct completion *comp, long code)
914 EXPORT_SYMBOL(complete_and_exit);
916 asmlinkage long sys_exit(int error_code)
918 do_exit((error_code&0xff)<<8);
921 task_t fastcall *next_thread(const task_t *p)
923 return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
926 EXPORT_SYMBOL(next_thread);
929 * Take down every thread in the group. This is called by fatal signals
930 * as well as by sys_exit_group (below).
933 do_group_exit(int exit_code)
935 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
937 if (current->signal->flags & SIGNAL_GROUP_EXIT)
938 exit_code = current->signal->group_exit_code;
939 else if (!thread_group_empty(current)) {
940 struct signal_struct *const sig = current->signal;
941 struct sighand_struct *const sighand = current->sighand;
942 read_lock(&tasklist_lock);
943 spin_lock_irq(&sighand->siglock);
944 if (sig->flags & SIGNAL_GROUP_EXIT)
945 /* Another thread got here before we took the lock. */
946 exit_code = sig->group_exit_code;
948 sig->group_exit_code = exit_code;
949 zap_other_threads(current);
951 spin_unlock_irq(&sighand->siglock);
952 read_unlock(&tasklist_lock);
960 * this kills every thread in the thread group. Note that any externally
961 * wait4()-ing process will get the correct exit code - even if this
962 * thread is not the thread group leader.
964 asmlinkage void sys_exit_group(int error_code)
966 do_group_exit((error_code & 0xff) << 8);
969 static int eligible_child(pid_t pid, int options, task_t *p)
975 if (process_group(p) != process_group(current))
977 } else if (pid != -1) {
978 if (process_group(p) != -pid)
983 * Do not consider detached threads that are
986 if (p->exit_signal == -1 && !p->ptrace)
989 /* Wait for all children (clone and not) if __WALL is set;
990 * otherwise, wait for clone children *only* if __WCLONE is
991 * set; otherwise, wait for non-clone children *only*. (Note:
992 * A "clone" child here is one that reports to its parent
993 * using a signal other than SIGCHLD.) */
994 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
995 && !(options & __WALL))
998 * Do not consider thread group leaders that are
999 * in a non-empty thread group:
1001 if (current->tgid != p->tgid && delay_group_leader(p))
1004 if (security_task_wait(p))
1010 static int wait_noreap_copyout(task_t *p, pid_t pid, uid_t uid,
1011 int why, int status,
1012 struct siginfo __user *infop,
1013 struct rusage __user *rusagep)
1015 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
1018 retval = put_user(SIGCHLD, &infop->si_signo);
1020 retval = put_user(0, &infop->si_errno);
1022 retval = put_user((short)why, &infop->si_code);
1024 retval = put_user(pid, &infop->si_pid);
1026 retval = put_user(uid, &infop->si_uid);
1028 retval = put_user(status, &infop->si_status);
1035 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1036 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1037 * the lock and this task is uninteresting. If we return nonzero, we have
1038 * released the lock and the system call should return.
1040 static int wait_task_zombie(task_t *p, int noreap,
1041 struct siginfo __user *infop,
1042 int __user *stat_addr, struct rusage __user *ru)
1044 unsigned long state;
1048 if (unlikely(noreap)) {
1051 int exit_code = p->exit_code;
1054 if (unlikely(p->exit_state != EXIT_ZOMBIE))
1056 if (unlikely(p->exit_signal == -1 && p->ptrace == 0))
1059 read_unlock(&tasklist_lock);
1060 if ((exit_code & 0x7f) == 0) {
1062 status = exit_code >> 8;
1064 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1065 status = exit_code & 0x7f;
1067 return wait_noreap_copyout(p, pid, uid, why,
1072 * Try to move the task's state to DEAD
1073 * only one thread is allowed to do this:
1075 state = xchg(&p->exit_state, EXIT_DEAD);
1076 if (state != EXIT_ZOMBIE) {
1077 BUG_ON(state != EXIT_DEAD);
1080 if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) {
1082 * This can only happen in a race with a ptraced thread
1083 * dying on another processor.
1088 if (likely(p->real_parent == p->parent) && likely(p->signal)) {
1089 struct signal_struct *psig;
1090 struct signal_struct *sig;
1093 * The resource counters for the group leader are in its
1094 * own task_struct. Those for dead threads in the group
1095 * are in its signal_struct, as are those for the child
1096 * processes it has previously reaped. All these
1097 * accumulate in the parent's signal_struct c* fields.
1099 * We don't bother to take a lock here to protect these
1100 * p->signal fields, because they are only touched by
1101 * __exit_signal, which runs with tasklist_lock
1102 * write-locked anyway, and so is excluded here. We do
1103 * need to protect the access to p->parent->signal fields,
1104 * as other threads in the parent group can be right
1105 * here reaping other children at the same time.
1107 spin_lock_irq(&p->parent->sighand->siglock);
1108 psig = p->parent->signal;
1111 cputime_add(psig->cutime,
1112 cputime_add(p->utime,
1113 cputime_add(sig->utime,
1116 cputime_add(psig->cstime,
1117 cputime_add(p->stime,
1118 cputime_add(sig->stime,
1121 p->min_flt + sig->min_flt + sig->cmin_flt;
1123 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1125 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1127 p->nivcsw + sig->nivcsw + sig->cnivcsw;
1128 spin_unlock_irq(&p->parent->sighand->siglock);
1132 * Now we are sure this task is interesting, and no other
1133 * thread can reap it because we set its state to EXIT_DEAD.
1135 read_unlock(&tasklist_lock);
1137 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1138 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1139 ? p->signal->group_exit_code : p->exit_code;
1140 if (!retval && stat_addr)
1141 retval = put_user(status, stat_addr);
1142 if (!retval && infop)
1143 retval = put_user(SIGCHLD, &infop->si_signo);
1144 if (!retval && infop)
1145 retval = put_user(0, &infop->si_errno);
1146 if (!retval && infop) {
1149 if ((status & 0x7f) == 0) {
1153 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1156 retval = put_user((short)why, &infop->si_code);
1158 retval = put_user(status, &infop->si_status);
1160 if (!retval && infop)
1161 retval = put_user(p->pid, &infop->si_pid);
1162 if (!retval && infop)
1163 retval = put_user(p->uid, &infop->si_uid);
1165 // TODO: is this safe?
1166 p->exit_state = EXIT_ZOMBIE;
1170 if (p->real_parent != p->parent) {
1171 write_lock_irq(&tasklist_lock);
1172 /* Double-check with lock held. */
1173 if (p->real_parent != p->parent) {
1175 // TODO: is this safe?
1176 p->exit_state = EXIT_ZOMBIE;
1178 * If this is not a detached task, notify the parent.
1179 * If it's still not detached after that, don't release
1182 if (p->exit_signal != -1) {
1183 do_notify_parent(p, p->exit_signal);
1184 if (p->exit_signal != -1)
1188 write_unlock_irq(&tasklist_lock);
1197 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1198 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1199 * the lock and this task is uninteresting. If we return nonzero, we have
1200 * released the lock and the system call should return.
1202 static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap,
1203 struct siginfo __user *infop,
1204 int __user *stat_addr, struct rusage __user *ru)
1206 int retval, exit_code;
1210 if (delayed_group_leader && !(p->ptrace & PT_PTRACED) &&
1211 p->signal && p->signal->group_stop_count > 0)
1213 * A group stop is in progress and this is the group leader.
1214 * We won't report until all threads have stopped.
1219 * Now we are pretty sure this task is interesting.
1220 * Make sure it doesn't get reaped out from under us while we
1221 * give up the lock and then examine it below. We don't want to
1222 * keep holding onto the tasklist_lock while we call getrusage and
1223 * possibly take page faults for user memory.
1226 read_unlock(&tasklist_lock);
1228 if (unlikely(noreap)) {
1231 int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
1233 exit_code = p->exit_code;
1234 if (unlikely(!exit_code) ||
1235 unlikely(p->state & TASK_TRACED))
1237 return wait_noreap_copyout(p, pid, uid,
1238 why, (exit_code << 8) | 0x7f,
1242 write_lock_irq(&tasklist_lock);
1245 * This uses xchg to be atomic with the thread resuming and setting
1246 * it. It must also be done with the write lock held to prevent a
1247 * race with the EXIT_ZOMBIE case.
1249 exit_code = xchg(&p->exit_code, 0);
1250 if (unlikely(p->exit_state)) {
1252 * The task resumed and then died. Let the next iteration
1253 * catch it in EXIT_ZOMBIE. Note that exit_code might
1254 * already be zero here if it resumed and did _exit(0).
1255 * The task itself is dead and won't touch exit_code again;
1256 * other processors in this function are locked out.
1258 p->exit_code = exit_code;
1261 if (unlikely(exit_code == 0)) {
1263 * Another thread in this function got to it first, or it
1264 * resumed, or it resumed and then died.
1266 write_unlock_irq(&tasklist_lock);
1270 * We are returning to the wait loop without having successfully
1271 * removed the process and having released the lock. We cannot
1272 * continue, since the "p" task pointer is potentially stale.
1274 * Return -EAGAIN, and do_wait() will restart the loop from the
1275 * beginning. Do _not_ re-acquire the lock.
1280 /* move to end of parent's list to avoid starvation */
1282 add_parent(p, p->parent);
1284 write_unlock_irq(&tasklist_lock);
1286 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1287 if (!retval && stat_addr)
1288 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1289 if (!retval && infop)
1290 retval = put_user(SIGCHLD, &infop->si_signo);
1291 if (!retval && infop)
1292 retval = put_user(0, &infop->si_errno);
1293 if (!retval && infop)
1294 retval = put_user((short)((p->ptrace & PT_PTRACED)
1295 ? CLD_TRAPPED : CLD_STOPPED),
1297 if (!retval && infop)
1298 retval = put_user(exit_code, &infop->si_status);
1299 if (!retval && infop)
1300 retval = put_user(p->pid, &infop->si_pid);
1301 if (!retval && infop)
1302 retval = put_user(p->uid, &infop->si_uid);
1312 * Handle do_wait work for one task in a live, non-stopped state.
1313 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1314 * the lock and this task is uninteresting. If we return nonzero, we have
1315 * released the lock and the system call should return.
1317 static int wait_task_continued(task_t *p, int noreap,
1318 struct siginfo __user *infop,
1319 int __user *stat_addr, struct rusage __user *ru)
1325 if (unlikely(!p->signal))
1328 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1331 spin_lock_irq(&p->sighand->siglock);
1332 /* Re-check with the lock held. */
1333 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1334 spin_unlock_irq(&p->sighand->siglock);
1338 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1339 spin_unlock_irq(&p->sighand->siglock);
1344 read_unlock(&tasklist_lock);
1347 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1349 if (!retval && stat_addr)
1350 retval = put_user(0xffff, stat_addr);
1354 retval = wait_noreap_copyout(p, pid, uid,
1355 CLD_CONTINUED, SIGCONT,
1357 BUG_ON(retval == 0);
1364 static inline int my_ptrace_child(struct task_struct *p)
1366 if (!(p->ptrace & PT_PTRACED))
1368 if (!(p->ptrace & PT_ATTACHED))
1371 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1372 * we are the attacher. If we are the real parent, this is a race
1373 * inside ptrace_attach. It is waiting for the tasklist_lock,
1374 * which we have to switch the parent links, but has already set
1375 * the flags in p->ptrace.
1377 return (p->parent != p->real_parent);
1380 static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
1381 int __user *stat_addr, struct rusage __user *ru)
1383 DECLARE_WAITQUEUE(wait, current);
1384 struct task_struct *tsk;
1387 add_wait_queue(¤t->signal->wait_chldexit,&wait);
1390 * We will set this flag if we see any child that might later
1391 * match our criteria, even if we are not able to reap it yet.
1394 current->state = TASK_INTERRUPTIBLE;
1395 read_lock(&tasklist_lock);
1398 struct task_struct *p;
1399 struct list_head *_p;
1402 list_for_each(_p,&tsk->children) {
1403 p = list_entry(_p,struct task_struct,sibling);
1405 ret = eligible_child(pid, options, p);
1412 * When we hit the race with PTRACE_ATTACH,
1413 * we will not report this child. But the
1414 * race means it has not yet been moved to
1415 * our ptrace_children list, so we need to
1416 * set the flag here to avoid a spurious ECHILD
1417 * when the race happens with the only child.
1420 if (!my_ptrace_child(p))
1425 * It's stopped now, so it might later
1426 * continue, exit, or stop again.
1429 if (!(options & WUNTRACED) &&
1430 !my_ptrace_child(p))
1432 retval = wait_task_stopped(p, ret == 2,
1433 (options & WNOWAIT),
1436 if (retval == -EAGAIN)
1438 if (retval != 0) /* He released the lock. */
1443 if (p->exit_state == EXIT_DEAD)
1445 // case EXIT_ZOMBIE:
1446 if (p->exit_state == EXIT_ZOMBIE) {
1448 * Eligible but we cannot release
1452 goto check_continued;
1453 if (!likely(options & WEXITED))
1455 retval = wait_task_zombie(
1456 p, (options & WNOWAIT),
1457 infop, stat_addr, ru);
1458 /* He released the lock. */
1465 * It's running now, so it might later
1466 * exit, stop, or stop and then continue.
1469 if (!unlikely(options & WCONTINUED))
1471 retval = wait_task_continued(
1472 p, (options & WNOWAIT),
1473 infop, stat_addr, ru);
1474 if (retval != 0) /* He released the lock. */
1480 list_for_each(_p, &tsk->ptrace_children) {
1481 p = list_entry(_p, struct task_struct,
1483 if (!eligible_child(pid, options, p))
1489 if (options & __WNOTHREAD)
1491 tsk = next_thread(tsk);
1492 if (tsk->signal != current->signal)
1494 } while (tsk != current);
1496 read_unlock(&tasklist_lock);
1499 if (options & WNOHANG)
1501 retval = -ERESTARTSYS;
1502 if (signal_pending(current))
1509 current->state = TASK_RUNNING;
1510 remove_wait_queue(¤t->signal->wait_chldexit,&wait);
1516 * For a WNOHANG return, clear out all the fields
1517 * we would set so the user can easily tell the
1521 retval = put_user(0, &infop->si_signo);
1523 retval = put_user(0, &infop->si_errno);
1525 retval = put_user(0, &infop->si_code);
1527 retval = put_user(0, &infop->si_pid);
1529 retval = put_user(0, &infop->si_uid);
1531 retval = put_user(0, &infop->si_status);
1537 asmlinkage long sys_waitid(int which, pid_t pid,
1538 struct siginfo __user *infop, int options,
1539 struct rusage __user *ru)
1543 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1545 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1565 ret = do_wait(pid, options, infop, NULL, ru);
1567 /* avoid REGPARM breakage on x86: */
1568 prevent_tail_call(ret);
1572 asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
1573 int options, struct rusage __user *ru)
1577 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1578 __WNOTHREAD|__WCLONE|__WALL))
1580 ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru);
1582 /* avoid REGPARM breakage on x86: */
1583 prevent_tail_call(ret);
1587 #ifdef __ARCH_WANT_SYS_WAITPID
1590 * sys_waitpid() remains for compatibility. waitpid() should be
1591 * implemented by calling sys_wait4() from libc.a.
1593 asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
1595 return sys_wait4(pid, stat_addr, options, NULL);