Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
[linux-2.6/lfs.git] / kernel / signal.c
blob72bb4f51f9634c448ad6eb4986d8ed7f35deb1f1
1 /*
2 * linux/kernel/signal.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
8 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
9 * Changes to use preallocated sigqueue structures
10 * to allow signals to be sent reliably.
13 #include <linux/slab.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/sched.h>
17 #include <linux/fs.h>
18 #include <linux/tty.h>
19 #include <linux/binfmts.h>
20 #include <linux/security.h>
21 #include <linux/syscalls.h>
22 #include <linux/ptrace.h>
23 #include <linux/signal.h>
24 #include <linux/signalfd.h>
25 #include <linux/capability.h>
26 #include <linux/freezer.h>
27 #include <linux/pid_namespace.h>
28 #include <linux/nsproxy.h>
30 #include <asm/param.h>
31 #include <asm/uaccess.h>
32 #include <asm/unistd.h>
33 #include <asm/siginfo.h>
34 #include "audit.h" /* audit_signal_info() */
37 * SLAB caches for signal bits.
40 static struct kmem_cache *sigqueue_cachep;
42 static int __sig_ignored(struct task_struct *t, int sig)
44 void __user *handler;
46 /* Is it explicitly or implicitly ignored? */
48 handler = t->sighand->action[sig - 1].sa.sa_handler;
49 return handler == SIG_IGN ||
50 (handler == SIG_DFL && sig_kernel_ignore(sig));
53 static int sig_ignored(struct task_struct *t, int sig)
56 * Tracers always want to know about signals..
58 if (t->ptrace & PT_PTRACED)
59 return 0;
62 * Blocked signals are never ignored, since the
63 * signal handler may change by the time it is
64 * unblocked.
66 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
67 return 0;
69 return __sig_ignored(t, sig);
73 * Re-calculate pending state from the set of locally pending
74 * signals, globally pending signals, and blocked signals.
76 static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
78 unsigned long ready;
79 long i;
81 switch (_NSIG_WORDS) {
82 default:
83 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
84 ready |= signal->sig[i] &~ blocked->sig[i];
85 break;
87 case 4: ready = signal->sig[3] &~ blocked->sig[3];
88 ready |= signal->sig[2] &~ blocked->sig[2];
89 ready |= signal->sig[1] &~ blocked->sig[1];
90 ready |= signal->sig[0] &~ blocked->sig[0];
91 break;
93 case 2: ready = signal->sig[1] &~ blocked->sig[1];
94 ready |= signal->sig[0] &~ blocked->sig[0];
95 break;
97 case 1: ready = signal->sig[0] &~ blocked->sig[0];
99 return ready != 0;
102 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
104 static int recalc_sigpending_tsk(struct task_struct *t)
106 if (t->signal->group_stop_count > 0 ||
107 PENDING(&t->pending, &t->blocked) ||
108 PENDING(&t->signal->shared_pending, &t->blocked)) {
109 set_tsk_thread_flag(t, TIF_SIGPENDING);
110 return 1;
113 * We must never clear the flag in another thread, or in current
114 * when it's possible the current syscall is returning -ERESTART*.
115 * So we don't clear it here, and only callers who know they should do.
117 return 0;
121 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
122 * This is superfluous when called on current, the wakeup is a harmless no-op.
124 void recalc_sigpending_and_wake(struct task_struct *t)
126 if (recalc_sigpending_tsk(t))
127 signal_wake_up(t, 0);
130 void recalc_sigpending(void)
132 if (!recalc_sigpending_tsk(current) && !freezing(current))
133 clear_thread_flag(TIF_SIGPENDING);
137 /* Given the mask, find the first available signal that should be serviced. */
139 int next_signal(struct sigpending *pending, sigset_t *mask)
141 unsigned long i, *s, *m, x;
142 int sig = 0;
144 s = pending->signal.sig;
145 m = mask->sig;
146 switch (_NSIG_WORDS) {
147 default:
148 for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m)
149 if ((x = *s &~ *m) != 0) {
150 sig = ffz(~x) + i*_NSIG_BPW + 1;
151 break;
153 break;
155 case 2: if ((x = s[0] &~ m[0]) != 0)
156 sig = 1;
157 else if ((x = s[1] &~ m[1]) != 0)
158 sig = _NSIG_BPW + 1;
159 else
160 break;
161 sig += ffz(~x);
162 break;
164 case 1: if ((x = *s &~ *m) != 0)
165 sig = ffz(~x) + 1;
166 break;
169 return sig;
172 static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
173 int override_rlimit)
175 struct sigqueue *q = NULL;
176 struct user_struct *user;
179 * In order to avoid problems with "switch_user()", we want to make
180 * sure that the compiler doesn't re-load "t->user"
182 user = t->user;
183 barrier();
184 atomic_inc(&user->sigpending);
185 if (override_rlimit ||
186 atomic_read(&user->sigpending) <=
187 t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
188 q = kmem_cache_alloc(sigqueue_cachep, flags);
189 if (unlikely(q == NULL)) {
190 atomic_dec(&user->sigpending);
191 } else {
192 INIT_LIST_HEAD(&q->list);
193 q->flags = 0;
194 q->user = get_uid(user);
196 return(q);
199 static void __sigqueue_free(struct sigqueue *q)
201 if (q->flags & SIGQUEUE_PREALLOC)
202 return;
203 atomic_dec(&q->user->sigpending);
204 free_uid(q->user);
205 kmem_cache_free(sigqueue_cachep, q);
208 void flush_sigqueue(struct sigpending *queue)
210 struct sigqueue *q;
212 sigemptyset(&queue->signal);
213 while (!list_empty(&queue->list)) {
214 q = list_entry(queue->list.next, struct sigqueue , list);
215 list_del_init(&q->list);
216 __sigqueue_free(q);
221 * Flush all pending signals for a task.
223 void flush_signals(struct task_struct *t)
225 unsigned long flags;
227 spin_lock_irqsave(&t->sighand->siglock, flags);
228 clear_tsk_thread_flag(t, TIF_SIGPENDING);
229 flush_sigqueue(&t->pending);
230 flush_sigqueue(&t->signal->shared_pending);
231 spin_unlock_irqrestore(&t->sighand->siglock, flags);
234 void ignore_signals(struct task_struct *t)
236 int i;
238 for (i = 0; i < _NSIG; ++i)
239 t->sighand->action[i].sa.sa_handler = SIG_IGN;
241 flush_signals(t);
245 * Flush all handlers for a task.
248 void
249 flush_signal_handlers(struct task_struct *t, int force_default)
251 int i;
252 struct k_sigaction *ka = &t->sighand->action[0];
253 for (i = _NSIG ; i != 0 ; i--) {
254 if (force_default || ka->sa.sa_handler != SIG_IGN)
255 ka->sa.sa_handler = SIG_DFL;
256 ka->sa.sa_flags = 0;
257 sigemptyset(&ka->sa.sa_mask);
258 ka++;
262 int unhandled_signal(struct task_struct *tsk, int sig)
264 if (is_global_init(tsk))
265 return 1;
266 if (tsk->ptrace & PT_PTRACED)
267 return 0;
268 return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) ||
269 (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL);
273 /* Notify the system that a driver wants to block all signals for this
274 * process, and wants to be notified if any signals at all were to be
275 * sent/acted upon. If the notifier routine returns non-zero, then the
276 * signal will be acted upon after all. If the notifier routine returns 0,
277 * then then signal will be blocked. Only one block per process is
278 * allowed. priv is a pointer to private data that the notifier routine
279 * can use to determine if the signal should be blocked or not. */
281 void
282 block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
284 unsigned long flags;
286 spin_lock_irqsave(&current->sighand->siglock, flags);
287 current->notifier_mask = mask;
288 current->notifier_data = priv;
289 current->notifier = notifier;
290 spin_unlock_irqrestore(&current->sighand->siglock, flags);
293 /* Notify the system that blocking has ended. */
295 void
296 unblock_all_signals(void)
298 unsigned long flags;
300 spin_lock_irqsave(&current->sighand->siglock, flags);
301 current->notifier = NULL;
302 current->notifier_data = NULL;
303 recalc_sigpending();
304 spin_unlock_irqrestore(&current->sighand->siglock, flags);
307 static int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
309 struct sigqueue *q, *first = NULL;
310 int still_pending = 0;
312 if (unlikely(!sigismember(&list->signal, sig)))
313 return 0;
316 * Collect the siginfo appropriate to this signal. Check if
317 * there is another siginfo for the same signal.
319 list_for_each_entry(q, &list->list, list) {
320 if (q->info.si_signo == sig) {
321 if (first) {
322 still_pending = 1;
323 break;
325 first = q;
328 if (first) {
329 list_del_init(&first->list);
330 copy_siginfo(info, &first->info);
331 __sigqueue_free(first);
332 if (!still_pending)
333 sigdelset(&list->signal, sig);
334 } else {
336 /* Ok, it wasn't in the queue. This must be
337 a fast-pathed signal or we must have been
338 out of queue space. So zero out the info.
340 sigdelset(&list->signal, sig);
341 info->si_signo = sig;
342 info->si_errno = 0;
343 info->si_code = 0;
344 info->si_pid = 0;
345 info->si_uid = 0;
347 return 1;
350 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
351 siginfo_t *info)
353 int sig = next_signal(pending, mask);
355 if (sig) {
356 if (current->notifier) {
357 if (sigismember(current->notifier_mask, sig)) {
358 if (!(current->notifier)(current->notifier_data)) {
359 clear_thread_flag(TIF_SIGPENDING);
360 return 0;
365 if (!collect_signal(sig, pending, info))
366 sig = 0;
369 return sig;
373 * Dequeue a signal and return the element to the caller, which is
374 * expected to free it.
376 * All callers have to hold the siglock.
378 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
380 int signr;
382 /* We only dequeue private signals from ourselves, we don't let
383 * signalfd steal them
385 signr = __dequeue_signal(&tsk->pending, mask, info);
386 if (!signr) {
387 signr = __dequeue_signal(&tsk->signal->shared_pending,
388 mask, info);
390 * itimer signal ?
392 * itimers are process shared and we restart periodic
393 * itimers in the signal delivery path to prevent DoS
394 * attacks in the high resolution timer case. This is
395 * compliant with the old way of self restarting
396 * itimers, as the SIGALRM is a legacy signal and only
397 * queued once. Changing the restart behaviour to
398 * restart the timer in the signal dequeue path is
399 * reducing the timer noise on heavy loaded !highres
400 * systems too.
402 if (unlikely(signr == SIGALRM)) {
403 struct hrtimer *tmr = &tsk->signal->real_timer;
405 if (!hrtimer_is_queued(tmr) &&
406 tsk->signal->it_real_incr.tv64 != 0) {
407 hrtimer_forward(tmr, tmr->base->get_time(),
408 tsk->signal->it_real_incr);
409 hrtimer_restart(tmr);
414 recalc_sigpending();
415 if (!signr)
416 return 0;
418 if (unlikely(sig_kernel_stop(signr))) {
420 * Set a marker that we have dequeued a stop signal. Our
421 * caller might release the siglock and then the pending
422 * stop signal it is about to process is no longer in the
423 * pending bitmasks, but must still be cleared by a SIGCONT
424 * (and overruled by a SIGKILL). So those cases clear this
425 * shared flag after we've set it. Note that this flag may
426 * remain set after the signal we return is ignored or
427 * handled. That doesn't matter because its only purpose
428 * is to alert stop-signal processing code when another
429 * processor has come along and cleared the flag.
431 if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT))
432 tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
434 if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
436 * Release the siglock to ensure proper locking order
437 * of timer locks outside of siglocks. Note, we leave
438 * irqs disabled here, since the posix-timers code is
439 * about to disable them again anyway.
441 spin_unlock(&tsk->sighand->siglock);
442 do_schedule_next_timer(info);
443 spin_lock(&tsk->sighand->siglock);
445 return signr;
449 * Tell a process that it has a new active signal..
451 * NOTE! we rely on the previous spin_lock to
452 * lock interrupts for us! We can only be called with
453 * "siglock" held, and the local interrupt must
454 * have been disabled when that got acquired!
456 * No need to set need_resched since signal event passing
457 * goes through ->blocked
459 void signal_wake_up(struct task_struct *t, int resume)
461 unsigned int mask;
463 set_tsk_thread_flag(t, TIF_SIGPENDING);
466 * For SIGKILL, we want to wake it up in the stopped/traced/killable
467 * case. We don't check t->state here because there is a race with it
468 * executing another processor and just now entering stopped state.
469 * By using wake_up_state, we ensure the process will wake up and
470 * handle its death signal.
472 mask = TASK_INTERRUPTIBLE;
473 if (resume)
474 mask |= TASK_WAKEKILL;
475 if (!wake_up_state(t, mask))
476 kick_process(t);
480 * Remove signals in mask from the pending set and queue.
481 * Returns 1 if any signals were found.
483 * All callers must be holding the siglock.
485 * This version takes a sigset mask and looks at all signals,
486 * not just those in the first mask word.
488 static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
490 struct sigqueue *q, *n;
491 sigset_t m;
493 sigandsets(&m, mask, &s->signal);
494 if (sigisemptyset(&m))
495 return 0;
497 signandsets(&s->signal, &s->signal, mask);
498 list_for_each_entry_safe(q, n, &s->list, list) {
499 if (sigismember(mask, q->info.si_signo)) {
500 list_del_init(&q->list);
501 __sigqueue_free(q);
504 return 1;
507 * Remove signals in mask from the pending set and queue.
508 * Returns 1 if any signals were found.
510 * All callers must be holding the siglock.
512 static int rm_from_queue(unsigned long mask, struct sigpending *s)
514 struct sigqueue *q, *n;
516 if (!sigtestsetmask(&s->signal, mask))
517 return 0;
519 sigdelsetmask(&s->signal, mask);
520 list_for_each_entry_safe(q, n, &s->list, list) {
521 if (q->info.si_signo < SIGRTMIN &&
522 (mask & sigmask(q->info.si_signo))) {
523 list_del_init(&q->list);
524 __sigqueue_free(q);
527 return 1;
531 * Bad permissions for sending the signal
533 static int check_kill_permission(int sig, struct siginfo *info,
534 struct task_struct *t)
536 struct pid *sid;
537 int error;
539 if (!valid_signal(sig))
540 return -EINVAL;
542 if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
543 return 0;
545 error = audit_signal_info(sig, t); /* Let audit system see the signal */
546 if (error)
547 return error;
549 if ((current->euid ^ t->suid) && (current->euid ^ t->uid) &&
550 (current->uid ^ t->suid) && (current->uid ^ t->uid) &&
551 !capable(CAP_KILL)) {
552 switch (sig) {
553 case SIGCONT:
554 sid = task_session(t);
556 * We don't return the error if sid == NULL. The
557 * task was unhashed, the caller must notice this.
559 if (!sid || sid == task_session(current))
560 break;
561 default:
562 return -EPERM;
566 return security_task_kill(t, info, sig, 0);
569 /* forward decl */
570 static void do_notify_parent_cldstop(struct task_struct *tsk, int why);
573 * Handle magic process-wide effects of stop/continue signals. Unlike
574 * the signal actions, these happen immediately at signal-generation
575 * time regardless of blocking, ignoring, or handling. This does the
576 * actual continuing for SIGCONT, but not the actual stopping for stop
577 * signals. The process stop is done as a signal action for SIG_DFL.
579 * Returns true if the signal should be actually delivered, otherwise
580 * it should be dropped.
582 static int prepare_signal(int sig, struct task_struct *p)
584 struct signal_struct *signal = p->signal;
585 struct task_struct *t;
587 if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) {
589 * The process is in the middle of dying, nothing to do.
591 } else if (sig_kernel_stop(sig)) {
593 * This is a stop signal. Remove SIGCONT from all queues.
595 rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
596 t = p;
597 do {
598 rm_from_queue(sigmask(SIGCONT), &t->pending);
599 } while_each_thread(p, t);
600 } else if (sig == SIGCONT) {
601 unsigned int why;
603 * Remove all stop signals from all queues,
604 * and wake all threads.
606 rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
607 t = p;
608 do {
609 unsigned int state;
610 rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
612 * If there is a handler for SIGCONT, we must make
613 * sure that no thread returns to user mode before
614 * we post the signal, in case it was the only
615 * thread eligible to run the signal handler--then
616 * it must not do anything between resuming and
617 * running the handler. With the TIF_SIGPENDING
618 * flag set, the thread will pause and acquire the
619 * siglock that we hold now and until we've queued
620 * the pending signal.
622 * Wake up the stopped thread _after_ setting
623 * TIF_SIGPENDING
625 state = __TASK_STOPPED;
626 if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
627 set_tsk_thread_flag(t, TIF_SIGPENDING);
628 state |= TASK_INTERRUPTIBLE;
630 wake_up_state(t, state);
631 } while_each_thread(p, t);
634 * Notify the parent with CLD_CONTINUED if we were stopped.
636 * If we were in the middle of a group stop, we pretend it
637 * was already finished, and then continued. Since SIGCHLD
638 * doesn't queue we report only CLD_STOPPED, as if the next
639 * CLD_CONTINUED was dropped.
641 why = 0;
642 if (signal->flags & SIGNAL_STOP_STOPPED)
643 why |= SIGNAL_CLD_CONTINUED;
644 else if (signal->group_stop_count)
645 why |= SIGNAL_CLD_STOPPED;
647 if (why) {
649 * The first thread which returns from finish_stop()
650 * will take ->siglock, notice SIGNAL_CLD_MASK, and
651 * notify its parent. See get_signal_to_deliver().
653 signal->flags = why | SIGNAL_STOP_CONTINUED;
654 signal->group_stop_count = 0;
655 signal->group_exit_code = 0;
656 } else {
658 * We are not stopped, but there could be a stop
659 * signal in the middle of being processed after
660 * being removed from the queue. Clear that too.
662 signal->flags &= ~SIGNAL_STOP_DEQUEUED;
666 return !sig_ignored(p, sig);
670 * Test if P wants to take SIG. After we've checked all threads with this,
671 * it's equivalent to finding no threads not blocking SIG. Any threads not
672 * blocking SIG were ruled out because they are not running and already
673 * have pending signals. Such threads will dequeue from the shared queue
674 * as soon as they're available, so putting the signal on the shared queue
675 * will be equivalent to sending it to one such thread.
677 static inline int wants_signal(int sig, struct task_struct *p)
679 if (sigismember(&p->blocked, sig))
680 return 0;
681 if (p->flags & PF_EXITING)
682 return 0;
683 if (sig == SIGKILL)
684 return 1;
685 if (task_is_stopped_or_traced(p))
686 return 0;
687 return task_curr(p) || !signal_pending(p);
690 static void complete_signal(int sig, struct task_struct *p, int group)
692 struct signal_struct *signal = p->signal;
693 struct task_struct *t;
696 * Now find a thread we can wake up to take the signal off the queue.
698 * If the main thread wants the signal, it gets first crack.
699 * Probably the least surprising to the average bear.
701 if (wants_signal(sig, p))
702 t = p;
703 else if (!group || thread_group_empty(p))
705 * There is just one thread and it does not need to be woken.
706 * It will dequeue unblocked signals before it runs again.
708 return;
709 else {
711 * Otherwise try to find a suitable thread.
713 t = signal->curr_target;
714 while (!wants_signal(sig, t)) {
715 t = next_thread(t);
716 if (t == signal->curr_target)
718 * No thread needs to be woken.
719 * Any eligible threads will see
720 * the signal in the queue soon.
722 return;
724 signal->curr_target = t;
728 * Found a killable thread. If the signal will be fatal,
729 * then start taking the whole group down immediately.
731 if (sig_fatal(p, sig) &&
732 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
733 !sigismember(&t->real_blocked, sig) &&
734 (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
736 * This signal will be fatal to the whole group.
738 if (!sig_kernel_coredump(sig)) {
740 * Start a group exit and wake everybody up.
741 * This way we don't have other threads
742 * running and doing things after a slower
743 * thread has the fatal signal pending.
745 signal->flags = SIGNAL_GROUP_EXIT;
746 signal->group_exit_code = sig;
747 signal->group_stop_count = 0;
748 t = p;
749 do {
750 sigaddset(&t->pending.signal, SIGKILL);
751 signal_wake_up(t, 1);
752 } while_each_thread(p, t);
753 return;
758 * The signal is already in the shared-pending queue.
759 * Tell the chosen thread to wake up and dequeue it.
761 signal_wake_up(t, sig == SIGKILL);
762 return;
765 static inline int legacy_queue(struct sigpending *signals, int sig)
767 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
770 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
771 int group)
773 struct sigpending *pending;
774 struct sigqueue *q;
776 assert_spin_locked(&t->sighand->siglock);
777 if (!prepare_signal(sig, t))
778 return 0;
780 pending = group ? &t->signal->shared_pending : &t->pending;
782 * Short-circuit ignored signals and support queuing
783 * exactly one non-rt signal, so that we can get more
784 * detailed information about the cause of the signal.
786 if (legacy_queue(pending, sig))
787 return 0;
789 * fast-pathed signals for kernel-internal things like SIGSTOP
790 * or SIGKILL.
792 if (info == SEND_SIG_FORCED)
793 goto out_set;
795 /* Real-time signals must be queued if sent by sigqueue, or
796 some other real-time mechanism. It is implementation
797 defined whether kill() does so. We attempt to do so, on
798 the principle of least surprise, but since kill is not
799 allowed to fail with EAGAIN when low on memory we just
800 make sure at least one signal gets delivered and don't
801 pass on the info struct. */
803 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
804 (is_si_special(info) ||
805 info->si_code >= 0)));
806 if (q) {
807 list_add_tail(&q->list, &pending->list);
808 switch ((unsigned long) info) {
809 case (unsigned long) SEND_SIG_NOINFO:
810 q->info.si_signo = sig;
811 q->info.si_errno = 0;
812 q->info.si_code = SI_USER;
813 q->info.si_pid = task_pid_vnr(current);
814 q->info.si_uid = current->uid;
815 break;
816 case (unsigned long) SEND_SIG_PRIV:
817 q->info.si_signo = sig;
818 q->info.si_errno = 0;
819 q->info.si_code = SI_KERNEL;
820 q->info.si_pid = 0;
821 q->info.si_uid = 0;
822 break;
823 default:
824 copy_siginfo(&q->info, info);
825 break;
827 } else if (!is_si_special(info)) {
828 if (sig >= SIGRTMIN && info->si_code != SI_USER)
830 * Queue overflow, abort. We may abort if the signal was rt
831 * and sent by user using something other than kill().
833 return -EAGAIN;
836 out_set:
837 signalfd_notify(t, sig);
838 sigaddset(&pending->signal, sig);
839 complete_signal(sig, t, group);
840 return 0;
843 int print_fatal_signals;
845 static void print_fatal_signal(struct pt_regs *regs, int signr)
847 printk("%s/%d: potentially unexpected fatal signal %d.\n",
848 current->comm, task_pid_nr(current), signr);
850 #if defined(__i386__) && !defined(__arch_um__)
851 printk("code at %08lx: ", regs->ip);
853 int i;
854 for (i = 0; i < 16; i++) {
855 unsigned char insn;
857 __get_user(insn, (unsigned char *)(regs->ip + i));
858 printk("%02x ", insn);
861 #endif
862 printk("\n");
863 show_regs(regs);
866 static int __init setup_print_fatal_signals(char *str)
868 get_option (&str, &print_fatal_signals);
870 return 1;
873 __setup("print-fatal-signals=", setup_print_fatal_signals);
876 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
878 return send_signal(sig, info, p, 1);
881 static int
882 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
884 return send_signal(sig, info, t, 0);
888 * Force a signal that the process can't ignore: if necessary
889 * we unblock the signal and change any SIG_IGN to SIG_DFL.
891 * Note: If we unblock the signal, we always reset it to SIG_DFL,
892 * since we do not want to have a signal handler that was blocked
893 * be invoked when user space had explicitly blocked it.
895 * We don't want to have recursive SIGSEGV's etc, for example,
896 * that is why we also clear SIGNAL_UNKILLABLE.
899 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
901 unsigned long int flags;
902 int ret, blocked, ignored;
903 struct k_sigaction *action;
905 spin_lock_irqsave(&t->sighand->siglock, flags);
906 action = &t->sighand->action[sig-1];
907 ignored = action->sa.sa_handler == SIG_IGN;
908 blocked = sigismember(&t->blocked, sig);
909 if (blocked || ignored) {
910 action->sa.sa_handler = SIG_DFL;
911 if (blocked) {
912 sigdelset(&t->blocked, sig);
913 recalc_sigpending_and_wake(t);
916 if (action->sa.sa_handler == SIG_DFL)
917 t->signal->flags &= ~SIGNAL_UNKILLABLE;
918 ret = specific_send_sig_info(sig, info, t);
919 spin_unlock_irqrestore(&t->sighand->siglock, flags);
921 return ret;
924 void
925 force_sig_specific(int sig, struct task_struct *t)
927 force_sig_info(sig, SEND_SIG_FORCED, t);
931 * Nuke all other threads in the group.
933 void zap_other_threads(struct task_struct *p)
935 struct task_struct *t;
937 p->signal->group_stop_count = 0;
939 for (t = next_thread(p); t != p; t = next_thread(t)) {
941 * Don't bother with already dead threads
943 if (t->exit_state)
944 continue;
946 /* SIGKILL will be handled before any pending SIGSTOP */
947 sigaddset(&t->pending.signal, SIGKILL);
948 signal_wake_up(t, 1);
952 int __fatal_signal_pending(struct task_struct *tsk)
954 return sigismember(&tsk->pending.signal, SIGKILL);
956 EXPORT_SYMBOL(__fatal_signal_pending);
958 struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
960 struct sighand_struct *sighand;
962 rcu_read_lock();
963 for (;;) {
964 sighand = rcu_dereference(tsk->sighand);
965 if (unlikely(sighand == NULL))
966 break;
968 spin_lock_irqsave(&sighand->siglock, *flags);
969 if (likely(sighand == tsk->sighand))
970 break;
971 spin_unlock_irqrestore(&sighand->siglock, *flags);
973 rcu_read_unlock();
975 return sighand;
978 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
980 unsigned long flags;
981 int ret;
983 ret = check_kill_permission(sig, info, p);
985 if (!ret && sig) {
986 ret = -ESRCH;
987 if (lock_task_sighand(p, &flags)) {
988 ret = __group_send_sig_info(sig, info, p);
989 unlock_task_sighand(p, &flags);
993 return ret;
997 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
998 * control characters do (^C, ^Z etc)
1001 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1003 struct task_struct *p = NULL;
1004 int retval, success;
1006 success = 0;
1007 retval = -ESRCH;
1008 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1009 int err = group_send_sig_info(sig, info, p);
1010 success |= !err;
1011 retval = err;
1012 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1013 return success ? 0 : retval;
1016 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1018 int error = -ESRCH;
1019 struct task_struct *p;
1021 rcu_read_lock();
1022 retry:
1023 p = pid_task(pid, PIDTYPE_PID);
1024 if (p) {
1025 error = group_send_sig_info(sig, info, p);
1026 if (unlikely(error == -ESRCH))
1028 * The task was unhashed in between, try again.
1029 * If it is dead, pid_task() will return NULL,
1030 * if we race with de_thread() it will find the
1031 * new leader.
1033 goto retry;
1035 rcu_read_unlock();
1037 return error;
1041 kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1043 int error;
1044 rcu_read_lock();
1045 error = kill_pid_info(sig, info, find_vpid(pid));
1046 rcu_read_unlock();
1047 return error;
1050 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1051 int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
1052 uid_t uid, uid_t euid, u32 secid)
1054 int ret = -EINVAL;
1055 struct task_struct *p;
1057 if (!valid_signal(sig))
1058 return ret;
1060 read_lock(&tasklist_lock);
1061 p = pid_task(pid, PIDTYPE_PID);
1062 if (!p) {
1063 ret = -ESRCH;
1064 goto out_unlock;
1066 if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
1067 && (euid != p->suid) && (euid != p->uid)
1068 && (uid != p->suid) && (uid != p->uid)) {
1069 ret = -EPERM;
1070 goto out_unlock;
1072 ret = security_task_kill(p, info, sig, secid);
1073 if (ret)
1074 goto out_unlock;
1075 if (sig && p->sighand) {
1076 unsigned long flags;
1077 spin_lock_irqsave(&p->sighand->siglock, flags);
1078 ret = __group_send_sig_info(sig, info, p);
1079 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1081 out_unlock:
1082 read_unlock(&tasklist_lock);
1083 return ret;
1085 EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
1088 * kill_something_info() interprets pid in interesting ways just like kill(2).
1090 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1091 * is probably wrong. Should make it like BSD or SYSV.
1094 static int kill_something_info(int sig, struct siginfo *info, int pid)
1096 int ret;
1098 if (pid > 0) {
1099 rcu_read_lock();
1100 ret = kill_pid_info(sig, info, find_vpid(pid));
1101 rcu_read_unlock();
1102 return ret;
1105 read_lock(&tasklist_lock);
1106 if (pid != -1) {
1107 ret = __kill_pgrp_info(sig, info,
1108 pid ? find_vpid(-pid) : task_pgrp(current));
1109 } else {
1110 int retval = 0, count = 0;
1111 struct task_struct * p;
1113 for_each_process(p) {
1114 if (p->pid > 1 && !same_thread_group(p, current)) {
1115 int err = group_send_sig_info(sig, info, p);
1116 ++count;
1117 if (err != -EPERM)
1118 retval = err;
1121 ret = count ? retval : -ESRCH;
1123 read_unlock(&tasklist_lock);
1125 return ret;
1129 * These are for backward compatibility with the rest of the kernel source.
1133 * The caller must ensure the task can't exit.
1136 send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1138 int ret;
1139 unsigned long flags;
1142 * Make sure legacy kernel users don't send in bad values
1143 * (normal paths check this in check_kill_permission).
1145 if (!valid_signal(sig))
1146 return -EINVAL;
1148 spin_lock_irqsave(&p->sighand->siglock, flags);
1149 ret = specific_send_sig_info(sig, info, p);
1150 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1151 return ret;
1154 #define __si_special(priv) \
1155 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1158 send_sig(int sig, struct task_struct *p, int priv)
1160 return send_sig_info(sig, __si_special(priv), p);
1163 void
1164 force_sig(int sig, struct task_struct *p)
1166 force_sig_info(sig, SEND_SIG_PRIV, p);
1170 * When things go south during signal handling, we
1171 * will force a SIGSEGV. And if the signal that caused
1172 * the problem was already a SIGSEGV, we'll want to
1173 * make sure we don't even try to deliver the signal..
1176 force_sigsegv(int sig, struct task_struct *p)
1178 if (sig == SIGSEGV) {
1179 unsigned long flags;
1180 spin_lock_irqsave(&p->sighand->siglock, flags);
1181 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1182 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1184 force_sig(SIGSEGV, p);
1185 return 0;
1188 int kill_pgrp(struct pid *pid, int sig, int priv)
1190 int ret;
1192 read_lock(&tasklist_lock);
1193 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1194 read_unlock(&tasklist_lock);
1196 return ret;
1198 EXPORT_SYMBOL(kill_pgrp);
1200 int kill_pid(struct pid *pid, int sig, int priv)
1202 return kill_pid_info(sig, __si_special(priv), pid);
1204 EXPORT_SYMBOL(kill_pid);
1207 kill_proc(pid_t pid, int sig, int priv)
1209 int ret;
1211 rcu_read_lock();
1212 ret = kill_pid_info(sig, __si_special(priv), find_pid(pid));
1213 rcu_read_unlock();
1214 return ret;
1218 * These functions support sending signals using preallocated sigqueue
1219 * structures. This is needed "because realtime applications cannot
1220 * afford to lose notifications of asynchronous events, like timer
1221 * expirations or I/O completions". In the case of Posix Timers
1222 * we allocate the sigqueue structure from the timer_create. If this
1223 * allocation fails we are able to report the failure to the application
1224 * with an EAGAIN error.
1227 struct sigqueue *sigqueue_alloc(void)
1229 struct sigqueue *q;
1231 if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
1232 q->flags |= SIGQUEUE_PREALLOC;
1233 return(q);
1236 void sigqueue_free(struct sigqueue *q)
1238 unsigned long flags;
1239 spinlock_t *lock = &current->sighand->siglock;
1241 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1243 * If the signal is still pending remove it from the
1244 * pending queue. We must hold ->siglock while testing
1245 * q->list to serialize with collect_signal().
1247 spin_lock_irqsave(lock, flags);
1248 if (!list_empty(&q->list))
1249 list_del_init(&q->list);
1250 spin_unlock_irqrestore(lock, flags);
1252 q->flags &= ~SIGQUEUE_PREALLOC;
1253 __sigqueue_free(q);
1256 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1258 int sig = q->info.si_signo;
1259 struct sigpending *pending;
1260 unsigned long flags;
1261 int ret;
1263 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1265 ret = -1;
1266 if (!likely(lock_task_sighand(t, &flags)))
1267 goto ret;
1269 ret = 1; /* the signal is ignored */
1270 if (!prepare_signal(sig, t))
1271 goto out;
1273 ret = 0;
1274 if (unlikely(!list_empty(&q->list))) {
1276 * If an SI_TIMER entry is already queue just increment
1277 * the overrun count.
1279 BUG_ON(q->info.si_code != SI_TIMER);
1280 q->info.si_overrun++;
1281 goto out;
1284 signalfd_notify(t, sig);
1285 pending = group ? &t->signal->shared_pending : &t->pending;
1286 list_add_tail(&q->list, &pending->list);
1287 sigaddset(&pending->signal, sig);
1288 complete_signal(sig, t, group);
1289 out:
1290 unlock_task_sighand(t, &flags);
1291 ret:
1292 return ret;
1296 * Wake up any threads in the parent blocked in wait* syscalls.
1298 static inline void __wake_up_parent(struct task_struct *p,
1299 struct task_struct *parent)
1301 wake_up_interruptible_sync(&parent->signal->wait_chldexit);
1305 * Let a parent know about the death of a child.
1306 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1309 void do_notify_parent(struct task_struct *tsk, int sig)
1311 struct siginfo info;
1312 unsigned long flags;
1313 struct sighand_struct *psig;
1315 BUG_ON(sig == -1);
1317 /* do_notify_parent_cldstop should have been called instead. */
1318 BUG_ON(task_is_stopped_or_traced(tsk));
1320 BUG_ON(!tsk->ptrace &&
1321 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1323 info.si_signo = sig;
1324 info.si_errno = 0;
1326 * we are under tasklist_lock here so our parent is tied to
1327 * us and cannot exit and release its namespace.
1329 * the only it can is to switch its nsproxy with sys_unshare,
1330 * bu uncharing pid namespaces is not allowed, so we'll always
1331 * see relevant namespace
1333 * write_lock() currently calls preempt_disable() which is the
1334 * same as rcu_read_lock(), but according to Oleg, this is not
1335 * correct to rely on this
1337 rcu_read_lock();
1338 info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
1339 rcu_read_unlock();
1341 info.si_uid = tsk->uid;
1343 /* FIXME: find out whether or not this is supposed to be c*time. */
1344 info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime,
1345 tsk->signal->utime));
1346 info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime,
1347 tsk->signal->stime));
1349 info.si_status = tsk->exit_code & 0x7f;
1350 if (tsk->exit_code & 0x80)
1351 info.si_code = CLD_DUMPED;
1352 else if (tsk->exit_code & 0x7f)
1353 info.si_code = CLD_KILLED;
1354 else {
1355 info.si_code = CLD_EXITED;
1356 info.si_status = tsk->exit_code >> 8;
1359 psig = tsk->parent->sighand;
1360 spin_lock_irqsave(&psig->siglock, flags);
1361 if (!tsk->ptrace && sig == SIGCHLD &&
1362 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1363 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1365 * We are exiting and our parent doesn't care. POSIX.1
1366 * defines special semantics for setting SIGCHLD to SIG_IGN
1367 * or setting the SA_NOCLDWAIT flag: we should be reaped
1368 * automatically and not left for our parent's wait4 call.
1369 * Rather than having the parent do it as a magic kind of
1370 * signal handler, we just set this to tell do_exit that we
1371 * can be cleaned up without becoming a zombie. Note that
1372 * we still call __wake_up_parent in this case, because a
1373 * blocked sys_wait4 might now return -ECHILD.
1375 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1376 * is implementation-defined: we do (if you don't want
1377 * it, just use SIG_IGN instead).
1379 tsk->exit_signal = -1;
1380 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1381 sig = 0;
1383 if (valid_signal(sig) && sig > 0)
1384 __group_send_sig_info(sig, &info, tsk->parent);
1385 __wake_up_parent(tsk, tsk->parent);
1386 spin_unlock_irqrestore(&psig->siglock, flags);
1389 static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
1391 struct siginfo info;
1392 unsigned long flags;
1393 struct task_struct *parent;
1394 struct sighand_struct *sighand;
1396 if (tsk->ptrace & PT_PTRACED)
1397 parent = tsk->parent;
1398 else {
1399 tsk = tsk->group_leader;
1400 parent = tsk->real_parent;
1403 info.si_signo = SIGCHLD;
1404 info.si_errno = 0;
1406 * see comment in do_notify_parent() abot the following 3 lines
1408 rcu_read_lock();
1409 info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
1410 rcu_read_unlock();
1412 info.si_uid = tsk->uid;
1414 /* FIXME: find out whether or not this is supposed to be c*time. */
1415 info.si_utime = cputime_to_jiffies(tsk->utime);
1416 info.si_stime = cputime_to_jiffies(tsk->stime);
1418 info.si_code = why;
1419 switch (why) {
1420 case CLD_CONTINUED:
1421 info.si_status = SIGCONT;
1422 break;
1423 case CLD_STOPPED:
1424 info.si_status = tsk->signal->group_exit_code & 0x7f;
1425 break;
1426 case CLD_TRAPPED:
1427 info.si_status = tsk->exit_code & 0x7f;
1428 break;
1429 default:
1430 BUG();
1433 sighand = parent->sighand;
1434 spin_lock_irqsave(&sighand->siglock, flags);
1435 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1436 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1437 __group_send_sig_info(SIGCHLD, &info, parent);
1439 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1441 __wake_up_parent(tsk, parent);
1442 spin_unlock_irqrestore(&sighand->siglock, flags);
1445 static inline int may_ptrace_stop(void)
1447 if (!likely(current->ptrace & PT_PTRACED))
1448 return 0;
1450 * Are we in the middle of do_coredump?
1451 * If so and our tracer is also part of the coredump stopping
1452 * is a deadlock situation, and pointless because our tracer
1453 * is dead so don't allow us to stop.
1454 * If SIGKILL was already sent before the caller unlocked
1455 * ->siglock we must see ->core_waiters != 0. Otherwise it
1456 * is safe to enter schedule().
1458 if (unlikely(current->mm->core_waiters) &&
1459 unlikely(current->mm == current->parent->mm))
1460 return 0;
1462 return 1;
1466 * Return nonzero if there is a SIGKILL that should be waking us up.
1467 * Called with the siglock held.
1469 static int sigkill_pending(struct task_struct *tsk)
1471 return ((sigismember(&tsk->pending.signal, SIGKILL) ||
1472 sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) &&
1473 !unlikely(sigismember(&tsk->blocked, SIGKILL)));
1477 * This must be called with current->sighand->siglock held.
1479 * This should be the path for all ptrace stops.
1480 * We always set current->last_siginfo while stopped here.
1481 * That makes it a way to test a stopped process for
1482 * being ptrace-stopped vs being job-control-stopped.
1484 * If we actually decide not to stop at all because the tracer
1485 * is gone, we keep current->exit_code unless clear_code.
1487 static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
1489 int killed = 0;
1491 if (arch_ptrace_stop_needed(exit_code, info)) {
1493 * The arch code has something special to do before a
1494 * ptrace stop. This is allowed to block, e.g. for faults
1495 * on user stack pages. We can't keep the siglock while
1496 * calling arch_ptrace_stop, so we must release it now.
1497 * To preserve proper semantics, we must do this before
1498 * any signal bookkeeping like checking group_stop_count.
1499 * Meanwhile, a SIGKILL could come in before we retake the
1500 * siglock. That must prevent us from sleeping in TASK_TRACED.
1501 * So after regaining the lock, we must check for SIGKILL.
1503 spin_unlock_irq(&current->sighand->siglock);
1504 arch_ptrace_stop(exit_code, info);
1505 spin_lock_irq(&current->sighand->siglock);
1506 killed = sigkill_pending(current);
1510 * If there is a group stop in progress,
1511 * we must participate in the bookkeeping.
1513 if (current->signal->group_stop_count > 0)
1514 --current->signal->group_stop_count;
1516 current->last_siginfo = info;
1517 current->exit_code = exit_code;
1519 /* Let the debugger run. */
1520 __set_current_state(TASK_TRACED);
1521 spin_unlock_irq(&current->sighand->siglock);
1522 read_lock(&tasklist_lock);
1523 if (!unlikely(killed) && may_ptrace_stop()) {
1524 do_notify_parent_cldstop(current, CLD_TRAPPED);
1525 read_unlock(&tasklist_lock);
1526 schedule();
1527 } else {
1529 * By the time we got the lock, our tracer went away.
1530 * Don't drop the lock yet, another tracer may come.
1532 __set_current_state(TASK_RUNNING);
1533 if (clear_code)
1534 current->exit_code = 0;
1535 read_unlock(&tasklist_lock);
1539 * While in TASK_TRACED, we were considered "frozen enough".
1540 * Now that we woke up, it's crucial if we're supposed to be
1541 * frozen that we freeze now before running anything substantial.
1543 try_to_freeze();
1546 * We are back. Now reacquire the siglock before touching
1547 * last_siginfo, so that we are sure to have synchronized with
1548 * any signal-sending on another CPU that wants to examine it.
1550 spin_lock_irq(&current->sighand->siglock);
1551 current->last_siginfo = NULL;
1554 * Queued signals ignored us while we were stopped for tracing.
1555 * So check for any that we should take before resuming user mode.
1556 * This sets TIF_SIGPENDING, but never clears it.
1558 recalc_sigpending_tsk(current);
1561 void ptrace_notify(int exit_code)
1563 siginfo_t info;
1565 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1567 memset(&info, 0, sizeof info);
1568 info.si_signo = SIGTRAP;
1569 info.si_code = exit_code;
1570 info.si_pid = task_pid_vnr(current);
1571 info.si_uid = current->uid;
1573 /* Let the debugger run. */
1574 spin_lock_irq(&current->sighand->siglock);
1575 ptrace_stop(exit_code, 1, &info);
1576 spin_unlock_irq(&current->sighand->siglock);
1579 static void
1580 finish_stop(int stop_count)
1583 * If there are no other threads in the group, or if there is
1584 * a group stop in progress and we are the last to stop,
1585 * report to the parent. When ptraced, every thread reports itself.
1587 if (stop_count == 0 || (current->ptrace & PT_PTRACED)) {
1588 read_lock(&tasklist_lock);
1589 do_notify_parent_cldstop(current, CLD_STOPPED);
1590 read_unlock(&tasklist_lock);
1593 do {
1594 schedule();
1595 } while (try_to_freeze());
1597 * Now we don't run again until continued.
1599 current->exit_code = 0;
1603 * This performs the stopping for SIGSTOP and other stop signals.
1604 * We have to stop all threads in the thread group.
1605 * Returns nonzero if we've actually stopped and released the siglock.
1606 * Returns zero if we didn't stop and still hold the siglock.
1608 static int do_signal_stop(int signr)
1610 struct signal_struct *sig = current->signal;
1611 int stop_count;
1613 if (sig->group_stop_count > 0) {
1615 * There is a group stop in progress. We don't need to
1616 * start another one.
1618 stop_count = --sig->group_stop_count;
1619 } else {
1620 struct task_struct *t;
1622 if (unlikely((sig->flags & (SIGNAL_STOP_DEQUEUED | SIGNAL_UNKILLABLE))
1623 != SIGNAL_STOP_DEQUEUED) ||
1624 unlikely(signal_group_exit(sig)))
1625 return 0;
1627 * There is no group stop already in progress.
1628 * We must initiate one now.
1630 sig->group_exit_code = signr;
1632 stop_count = 0;
1633 for (t = next_thread(current); t != current; t = next_thread(t))
1635 * Setting state to TASK_STOPPED for a group
1636 * stop is always done with the siglock held,
1637 * so this check has no races.
1639 if (!(t->flags & PF_EXITING) &&
1640 !task_is_stopped_or_traced(t)) {
1641 stop_count++;
1642 signal_wake_up(t, 0);
1644 sig->group_stop_count = stop_count;
1647 if (stop_count == 0)
1648 sig->flags = SIGNAL_STOP_STOPPED;
1649 current->exit_code = sig->group_exit_code;
1650 __set_current_state(TASK_STOPPED);
1652 spin_unlock_irq(&current->sighand->siglock);
1653 finish_stop(stop_count);
1654 return 1;
1657 static int ptrace_signal(int signr, siginfo_t *info,
1658 struct pt_regs *regs, void *cookie)
1660 if (!(current->ptrace & PT_PTRACED))
1661 return signr;
1663 ptrace_signal_deliver(regs, cookie);
1665 /* Let the debugger run. */
1666 ptrace_stop(signr, 0, info);
1668 /* We're back. Did the debugger cancel the sig? */
1669 signr = current->exit_code;
1670 if (signr == 0)
1671 return signr;
1673 current->exit_code = 0;
1675 /* Update the siginfo structure if the signal has
1676 changed. If the debugger wanted something
1677 specific in the siginfo structure then it should
1678 have updated *info via PTRACE_SETSIGINFO. */
1679 if (signr != info->si_signo) {
1680 info->si_signo = signr;
1681 info->si_errno = 0;
1682 info->si_code = SI_USER;
1683 info->si_pid = task_pid_vnr(current->parent);
1684 info->si_uid = current->parent->uid;
1687 /* If the (new) signal is now blocked, requeue it. */
1688 if (sigismember(&current->blocked, signr)) {
1689 specific_send_sig_info(signr, info, current);
1690 signr = 0;
1693 return signr;
1696 int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
1697 struct pt_regs *regs, void *cookie)
1699 struct sighand_struct *sighand = current->sighand;
1700 struct signal_struct *signal = current->signal;
1701 int signr;
1703 relock:
1705 * We'll jump back here after any time we were stopped in TASK_STOPPED.
1706 * While in TASK_STOPPED, we were considered "frozen enough".
1707 * Now that we woke up, it's crucial if we're supposed to be
1708 * frozen that we freeze now before running anything substantial.
1710 try_to_freeze();
1712 spin_lock_irq(&sighand->siglock);
1714 * Every stopped thread goes here after wakeup. Check to see if
1715 * we should notify the parent, prepare_signal(SIGCONT) encodes
1716 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
1718 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
1719 int why = (signal->flags & SIGNAL_STOP_CONTINUED)
1720 ? CLD_CONTINUED : CLD_STOPPED;
1721 signal->flags &= ~SIGNAL_CLD_MASK;
1722 spin_unlock_irq(&sighand->siglock);
1724 read_lock(&tasklist_lock);
1725 do_notify_parent_cldstop(current->group_leader, why);
1726 read_unlock(&tasklist_lock);
1727 goto relock;
1730 for (;;) {
1731 struct k_sigaction *ka;
1733 if (unlikely(signal->group_stop_count > 0) &&
1734 do_signal_stop(0))
1735 goto relock;
1737 signr = dequeue_signal(current, &current->blocked, info);
1738 if (!signr)
1739 break; /* will return 0 */
1741 if (signr != SIGKILL) {
1742 signr = ptrace_signal(signr, info, regs, cookie);
1743 if (!signr)
1744 continue;
1747 ka = &sighand->action[signr-1];
1748 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
1749 continue;
1750 if (ka->sa.sa_handler != SIG_DFL) {
1751 /* Run the handler. */
1752 *return_ka = *ka;
1754 if (ka->sa.sa_flags & SA_ONESHOT)
1755 ka->sa.sa_handler = SIG_DFL;
1757 break; /* will return non-zero "signr" value */
1761 * Now we are doing the default action for this signal.
1763 if (sig_kernel_ignore(signr)) /* Default is nothing. */
1764 continue;
1767 * Global init gets no signals it doesn't want.
1769 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
1770 !signal_group_exit(signal))
1771 continue;
1773 if (sig_kernel_stop(signr)) {
1775 * The default action is to stop all threads in
1776 * the thread group. The job control signals
1777 * do nothing in an orphaned pgrp, but SIGSTOP
1778 * always works. Note that siglock needs to be
1779 * dropped during the call to is_orphaned_pgrp()
1780 * because of lock ordering with tasklist_lock.
1781 * This allows an intervening SIGCONT to be posted.
1782 * We need to check for that and bail out if necessary.
1784 if (signr != SIGSTOP) {
1785 spin_unlock_irq(&sighand->siglock);
1787 /* signals can be posted during this window */
1789 if (is_current_pgrp_orphaned())
1790 goto relock;
1792 spin_lock_irq(&sighand->siglock);
1795 if (likely(do_signal_stop(signr))) {
1796 /* It released the siglock. */
1797 goto relock;
1801 * We didn't actually stop, due to a race
1802 * with SIGCONT or something like that.
1804 continue;
1807 spin_unlock_irq(&sighand->siglock);
1810 * Anything else is fatal, maybe with a core dump.
1812 current->flags |= PF_SIGNALED;
1814 if (sig_kernel_coredump(signr)) {
1815 if (print_fatal_signals)
1816 print_fatal_signal(regs, signr);
1818 * If it was able to dump core, this kills all
1819 * other threads in the group and synchronizes with
1820 * their demise. If we lost the race with another
1821 * thread getting here, it set group_exit_code
1822 * first and our do_group_exit call below will use
1823 * that value and ignore the one we pass it.
1825 do_coredump((long)signr, signr, regs);
1829 * Death signals, no core dump.
1831 do_group_exit(signr);
1832 /* NOTREACHED */
1834 spin_unlock_irq(&sighand->siglock);
1835 return signr;
1838 void exit_signals(struct task_struct *tsk)
1840 int group_stop = 0;
1841 struct task_struct *t;
1843 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
1844 tsk->flags |= PF_EXITING;
1845 return;
1848 spin_lock_irq(&tsk->sighand->siglock);
1850 * From now this task is not visible for group-wide signals,
1851 * see wants_signal(), do_signal_stop().
1853 tsk->flags |= PF_EXITING;
1854 if (!signal_pending(tsk))
1855 goto out;
1857 /* It could be that __group_complete_signal() choose us to
1858 * notify about group-wide signal. Another thread should be
1859 * woken now to take the signal since we will not.
1861 for (t = tsk; (t = next_thread(t)) != tsk; )
1862 if (!signal_pending(t) && !(t->flags & PF_EXITING))
1863 recalc_sigpending_and_wake(t);
1865 if (unlikely(tsk->signal->group_stop_count) &&
1866 !--tsk->signal->group_stop_count) {
1867 tsk->signal->flags = SIGNAL_STOP_STOPPED;
1868 group_stop = 1;
1870 out:
1871 spin_unlock_irq(&tsk->sighand->siglock);
1873 if (unlikely(group_stop)) {
1874 read_lock(&tasklist_lock);
1875 do_notify_parent_cldstop(tsk, CLD_STOPPED);
1876 read_unlock(&tasklist_lock);
1880 EXPORT_SYMBOL(recalc_sigpending);
1881 EXPORT_SYMBOL_GPL(dequeue_signal);
1882 EXPORT_SYMBOL(flush_signals);
1883 EXPORT_SYMBOL(force_sig);
1884 EXPORT_SYMBOL(kill_proc);
1885 EXPORT_SYMBOL(ptrace_notify);
1886 EXPORT_SYMBOL(send_sig);
1887 EXPORT_SYMBOL(send_sig_info);
1888 EXPORT_SYMBOL(sigprocmask);
1889 EXPORT_SYMBOL(block_all_signals);
1890 EXPORT_SYMBOL(unblock_all_signals);
1894 * System call entry points.
1897 asmlinkage long sys_restart_syscall(void)
1899 struct restart_block *restart = &current_thread_info()->restart_block;
1900 return restart->fn(restart);
1903 long do_no_restart_syscall(struct restart_block *param)
1905 return -EINTR;
1909 * We don't need to get the kernel lock - this is all local to this
1910 * particular thread.. (and that's good, because this is _heavily_
1911 * used by various programs)
1915 * This is also useful for kernel threads that want to temporarily
1916 * (or permanently) block certain signals.
1918 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
1919 * interface happily blocks "unblockable" signals like SIGKILL
1920 * and friends.
1922 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
1924 int error;
1926 spin_lock_irq(&current->sighand->siglock);
1927 if (oldset)
1928 *oldset = current->blocked;
1930 error = 0;
1931 switch (how) {
1932 case SIG_BLOCK:
1933 sigorsets(&current->blocked, &current->blocked, set);
1934 break;
1935 case SIG_UNBLOCK:
1936 signandsets(&current->blocked, &current->blocked, set);
1937 break;
1938 case SIG_SETMASK:
1939 current->blocked = *set;
1940 break;
1941 default:
1942 error = -EINVAL;
1944 recalc_sigpending();
1945 spin_unlock_irq(&current->sighand->siglock);
1947 return error;
1950 asmlinkage long
1951 sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize)
1953 int error = -EINVAL;
1954 sigset_t old_set, new_set;
1956 /* XXX: Don't preclude handling different sized sigset_t's. */
1957 if (sigsetsize != sizeof(sigset_t))
1958 goto out;
1960 if (set) {
1961 error = -EFAULT;
1962 if (copy_from_user(&new_set, set, sizeof(*set)))
1963 goto out;
1964 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1966 error = sigprocmask(how, &new_set, &old_set);
1967 if (error)
1968 goto out;
1969 if (oset)
1970 goto set_old;
1971 } else if (oset) {
1972 spin_lock_irq(&current->sighand->siglock);
1973 old_set = current->blocked;
1974 spin_unlock_irq(&current->sighand->siglock);
1976 set_old:
1977 error = -EFAULT;
1978 if (copy_to_user(oset, &old_set, sizeof(*oset)))
1979 goto out;
1981 error = 0;
1982 out:
1983 return error;
1986 long do_sigpending(void __user *set, unsigned long sigsetsize)
1988 long error = -EINVAL;
1989 sigset_t pending;
1991 if (sigsetsize > sizeof(sigset_t))
1992 goto out;
1994 spin_lock_irq(&current->sighand->siglock);
1995 sigorsets(&pending, &current->pending.signal,
1996 &current->signal->shared_pending.signal);
1997 spin_unlock_irq(&current->sighand->siglock);
1999 /* Outside the lock because only this thread touches it. */
2000 sigandsets(&pending, &current->blocked, &pending);
2002 error = -EFAULT;
2003 if (!copy_to_user(set, &pending, sigsetsize))
2004 error = 0;
2006 out:
2007 return error;
2010 asmlinkage long
2011 sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize)
2013 return do_sigpending(set, sigsetsize);
2016 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2018 int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
2020 int err;
2022 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2023 return -EFAULT;
2024 if (from->si_code < 0)
2025 return __copy_to_user(to, from, sizeof(siginfo_t))
2026 ? -EFAULT : 0;
2028 * If you change siginfo_t structure, please be sure
2029 * this code is fixed accordingly.
2030 * Please remember to update the signalfd_copyinfo() function
2031 * inside fs/signalfd.c too, in case siginfo_t changes.
2032 * It should never copy any pad contained in the structure
2033 * to avoid security leaks, but must copy the generic
2034 * 3 ints plus the relevant union member.
2036 err = __put_user(from->si_signo, &to->si_signo);
2037 err |= __put_user(from->si_errno, &to->si_errno);
2038 err |= __put_user((short)from->si_code, &to->si_code);
2039 switch (from->si_code & __SI_MASK) {
2040 case __SI_KILL:
2041 err |= __put_user(from->si_pid, &to->si_pid);
2042 err |= __put_user(from->si_uid, &to->si_uid);
2043 break;
2044 case __SI_TIMER:
2045 err |= __put_user(from->si_tid, &to->si_tid);
2046 err |= __put_user(from->si_overrun, &to->si_overrun);
2047 err |= __put_user(from->si_ptr, &to->si_ptr);
2048 break;
2049 case __SI_POLL:
2050 err |= __put_user(from->si_band, &to->si_band);
2051 err |= __put_user(from->si_fd, &to->si_fd);
2052 break;
2053 case __SI_FAULT:
2054 err |= __put_user(from->si_addr, &to->si_addr);
2055 #ifdef __ARCH_SI_TRAPNO
2056 err |= __put_user(from->si_trapno, &to->si_trapno);
2057 #endif
2058 break;
2059 case __SI_CHLD:
2060 err |= __put_user(from->si_pid, &to->si_pid);
2061 err |= __put_user(from->si_uid, &to->si_uid);
2062 err |= __put_user(from->si_status, &to->si_status);
2063 err |= __put_user(from->si_utime, &to->si_utime);
2064 err |= __put_user(from->si_stime, &to->si_stime);
2065 break;
2066 case __SI_RT: /* This is not generated by the kernel as of now. */
2067 case __SI_MESGQ: /* But this is */
2068 err |= __put_user(from->si_pid, &to->si_pid);
2069 err |= __put_user(from->si_uid, &to->si_uid);
2070 err |= __put_user(from->si_ptr, &to->si_ptr);
2071 break;
2072 default: /* this is just in case for now ... */
2073 err |= __put_user(from->si_pid, &to->si_pid);
2074 err |= __put_user(from->si_uid, &to->si_uid);
2075 break;
2077 return err;
2080 #endif
2082 asmlinkage long
2083 sys_rt_sigtimedwait(const sigset_t __user *uthese,
2084 siginfo_t __user *uinfo,
2085 const struct timespec __user *uts,
2086 size_t sigsetsize)
2088 int ret, sig;
2089 sigset_t these;
2090 struct timespec ts;
2091 siginfo_t info;
2092 long timeout = 0;
2094 /* XXX: Don't preclude handling different sized sigset_t's. */
2095 if (sigsetsize != sizeof(sigset_t))
2096 return -EINVAL;
2098 if (copy_from_user(&these, uthese, sizeof(these)))
2099 return -EFAULT;
2102 * Invert the set of allowed signals to get those we
2103 * want to block.
2105 sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));
2106 signotset(&these);
2108 if (uts) {
2109 if (copy_from_user(&ts, uts, sizeof(ts)))
2110 return -EFAULT;
2111 if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0
2112 || ts.tv_sec < 0)
2113 return -EINVAL;
2116 spin_lock_irq(&current->sighand->siglock);
2117 sig = dequeue_signal(current, &these, &info);
2118 if (!sig) {
2119 timeout = MAX_SCHEDULE_TIMEOUT;
2120 if (uts)
2121 timeout = (timespec_to_jiffies(&ts)
2122 + (ts.tv_sec || ts.tv_nsec));
2124 if (timeout) {
2125 /* None ready -- temporarily unblock those we're
2126 * interested while we are sleeping in so that we'll
2127 * be awakened when they arrive. */
2128 current->real_blocked = current->blocked;
2129 sigandsets(&current->blocked, &current->blocked, &these);
2130 recalc_sigpending();
2131 spin_unlock_irq(&current->sighand->siglock);
2133 timeout = schedule_timeout_interruptible(timeout);
2135 spin_lock_irq(&current->sighand->siglock);
2136 sig = dequeue_signal(current, &these, &info);
2137 current->blocked = current->real_blocked;
2138 siginitset(&current->real_blocked, 0);
2139 recalc_sigpending();
2142 spin_unlock_irq(&current->sighand->siglock);
2144 if (sig) {
2145 ret = sig;
2146 if (uinfo) {
2147 if (copy_siginfo_to_user(uinfo, &info))
2148 ret = -EFAULT;
2150 } else {
2151 ret = -EAGAIN;
2152 if (timeout)
2153 ret = -EINTR;
2156 return ret;
2159 asmlinkage long
2160 sys_kill(int pid, int sig)
2162 struct siginfo info;
2164 info.si_signo = sig;
2165 info.si_errno = 0;
2166 info.si_code = SI_USER;
2167 info.si_pid = task_tgid_vnr(current);
2168 info.si_uid = current->uid;
2170 return kill_something_info(sig, &info, pid);
2173 static int do_tkill(int tgid, int pid, int sig)
2175 int error;
2176 struct siginfo info;
2177 struct task_struct *p;
2178 unsigned long flags;
2180 error = -ESRCH;
2181 info.si_signo = sig;
2182 info.si_errno = 0;
2183 info.si_code = SI_TKILL;
2184 info.si_pid = task_tgid_vnr(current);
2185 info.si_uid = current->uid;
2187 rcu_read_lock();
2188 p = find_task_by_vpid(pid);
2189 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2190 error = check_kill_permission(sig, &info, p);
2192 * The null signal is a permissions and process existence
2193 * probe. No signal is actually delivered.
2195 * If lock_task_sighand() fails we pretend the task dies
2196 * after receiving the signal. The window is tiny, and the
2197 * signal is private anyway.
2199 if (!error && sig && lock_task_sighand(p, &flags)) {
2200 error = specific_send_sig_info(sig, &info, p);
2201 unlock_task_sighand(p, &flags);
2204 rcu_read_unlock();
2206 return error;
2210 * sys_tgkill - send signal to one specific thread
2211 * @tgid: the thread group ID of the thread
2212 * @pid: the PID of the thread
2213 * @sig: signal to be sent
2215 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2216 * exists but it's not belonging to the target process anymore. This
2217 * method solves the problem of threads exiting and PIDs getting reused.
2219 asmlinkage long sys_tgkill(int tgid, int pid, int sig)
2221 /* This is only valid for single tasks */
2222 if (pid <= 0 || tgid <= 0)
2223 return -EINVAL;
2225 return do_tkill(tgid, pid, sig);
2229 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2231 asmlinkage long
2232 sys_tkill(int pid, int sig)
2234 /* This is only valid for single tasks */
2235 if (pid <= 0)
2236 return -EINVAL;
2238 return do_tkill(0, pid, sig);
2241 asmlinkage long
2242 sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo)
2244 siginfo_t info;
2246 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2247 return -EFAULT;
2249 /* Not even root can pretend to send signals from the kernel.
2250 Nor can they impersonate a kill(), which adds source info. */
2251 if (info.si_code >= 0)
2252 return -EPERM;
2253 info.si_signo = sig;
2255 /* POSIX.1b doesn't mention process groups. */
2256 return kill_proc_info(sig, &info, pid);
2259 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
2261 struct task_struct *t = current;
2262 struct k_sigaction *k;
2263 sigset_t mask;
2265 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
2266 return -EINVAL;
2268 k = &t->sighand->action[sig-1];
2270 spin_lock_irq(&current->sighand->siglock);
2271 if (oact)
2272 *oact = *k;
2274 if (act) {
2275 sigdelsetmask(&act->sa.sa_mask,
2276 sigmask(SIGKILL) | sigmask(SIGSTOP));
2277 *k = *act;
2279 * POSIX 3.3.1.3:
2280 * "Setting a signal action to SIG_IGN for a signal that is
2281 * pending shall cause the pending signal to be discarded,
2282 * whether or not it is blocked."
2284 * "Setting a signal action to SIG_DFL for a signal that is
2285 * pending and whose default action is to ignore the signal
2286 * (for example, SIGCHLD), shall cause the pending signal to
2287 * be discarded, whether or not it is blocked"
2289 if (__sig_ignored(t, sig)) {
2290 sigemptyset(&mask);
2291 sigaddset(&mask, sig);
2292 rm_from_queue_full(&mask, &t->signal->shared_pending);
2293 do {
2294 rm_from_queue_full(&mask, &t->pending);
2295 t = next_thread(t);
2296 } while (t != current);
2300 spin_unlock_irq(&current->sighand->siglock);
2301 return 0;
2304 int
2305 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
2307 stack_t oss;
2308 int error;
2310 if (uoss) {
2311 oss.ss_sp = (void __user *) current->sas_ss_sp;
2312 oss.ss_size = current->sas_ss_size;
2313 oss.ss_flags = sas_ss_flags(sp);
2316 if (uss) {
2317 void __user *ss_sp;
2318 size_t ss_size;
2319 int ss_flags;
2321 error = -EFAULT;
2322 if (!access_ok(VERIFY_READ, uss, sizeof(*uss))
2323 || __get_user(ss_sp, &uss->ss_sp)
2324 || __get_user(ss_flags, &uss->ss_flags)
2325 || __get_user(ss_size, &uss->ss_size))
2326 goto out;
2328 error = -EPERM;
2329 if (on_sig_stack(sp))
2330 goto out;
2332 error = -EINVAL;
2335 * Note - this code used to test ss_flags incorrectly
2336 * old code may have been written using ss_flags==0
2337 * to mean ss_flags==SS_ONSTACK (as this was the only
2338 * way that worked) - this fix preserves that older
2339 * mechanism
2341 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
2342 goto out;
2344 if (ss_flags == SS_DISABLE) {
2345 ss_size = 0;
2346 ss_sp = NULL;
2347 } else {
2348 error = -ENOMEM;
2349 if (ss_size < MINSIGSTKSZ)
2350 goto out;
2353 current->sas_ss_sp = (unsigned long) ss_sp;
2354 current->sas_ss_size = ss_size;
2357 if (uoss) {
2358 error = -EFAULT;
2359 if (copy_to_user(uoss, &oss, sizeof(oss)))
2360 goto out;
2363 error = 0;
2364 out:
2365 return error;
2368 #ifdef __ARCH_WANT_SYS_SIGPENDING
2370 asmlinkage long
2371 sys_sigpending(old_sigset_t __user *set)
2373 return do_sigpending(set, sizeof(*set));
2376 #endif
2378 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
2379 /* Some platforms have their own version with special arguments others
2380 support only sys_rt_sigprocmask. */
2382 asmlinkage long
2383 sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset)
2385 int error;
2386 old_sigset_t old_set, new_set;
2388 if (set) {
2389 error = -EFAULT;
2390 if (copy_from_user(&new_set, set, sizeof(*set)))
2391 goto out;
2392 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
2394 spin_lock_irq(&current->sighand->siglock);
2395 old_set = current->blocked.sig[0];
2397 error = 0;
2398 switch (how) {
2399 default:
2400 error = -EINVAL;
2401 break;
2402 case SIG_BLOCK:
2403 sigaddsetmask(&current->blocked, new_set);
2404 break;
2405 case SIG_UNBLOCK:
2406 sigdelsetmask(&current->blocked, new_set);
2407 break;
2408 case SIG_SETMASK:
2409 current->blocked.sig[0] = new_set;
2410 break;
2413 recalc_sigpending();
2414 spin_unlock_irq(&current->sighand->siglock);
2415 if (error)
2416 goto out;
2417 if (oset)
2418 goto set_old;
2419 } else if (oset) {
2420 old_set = current->blocked.sig[0];
2421 set_old:
2422 error = -EFAULT;
2423 if (copy_to_user(oset, &old_set, sizeof(*oset)))
2424 goto out;
2426 error = 0;
2427 out:
2428 return error;
2430 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
2432 #ifdef __ARCH_WANT_SYS_RT_SIGACTION
2433 asmlinkage long
2434 sys_rt_sigaction(int sig,
2435 const struct sigaction __user *act,
2436 struct sigaction __user *oact,
2437 size_t sigsetsize)
2439 struct k_sigaction new_sa, old_sa;
2440 int ret = -EINVAL;
2442 /* XXX: Don't preclude handling different sized sigset_t's. */
2443 if (sigsetsize != sizeof(sigset_t))
2444 goto out;
2446 if (act) {
2447 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
2448 return -EFAULT;
2451 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
2453 if (!ret && oact) {
2454 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
2455 return -EFAULT;
2457 out:
2458 return ret;
2460 #endif /* __ARCH_WANT_SYS_RT_SIGACTION */
2462 #ifdef __ARCH_WANT_SYS_SGETMASK
2465 * For backwards compatibility. Functionality superseded by sigprocmask.
2467 asmlinkage long
2468 sys_sgetmask(void)
2470 /* SMP safe */
2471 return current->blocked.sig[0];
2474 asmlinkage long
2475 sys_ssetmask(int newmask)
2477 int old;
2479 spin_lock_irq(&current->sighand->siglock);
2480 old = current->blocked.sig[0];
2482 siginitset(&current->blocked, newmask & ~(sigmask(SIGKILL)|
2483 sigmask(SIGSTOP)));
2484 recalc_sigpending();
2485 spin_unlock_irq(&current->sighand->siglock);
2487 return old;
2489 #endif /* __ARCH_WANT_SGETMASK */
2491 #ifdef __ARCH_WANT_SYS_SIGNAL
2493 * For backwards compatibility. Functionality superseded by sigaction.
2495 asmlinkage unsigned long
2496 sys_signal(int sig, __sighandler_t handler)
2498 struct k_sigaction new_sa, old_sa;
2499 int ret;
2501 new_sa.sa.sa_handler = handler;
2502 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
2503 sigemptyset(&new_sa.sa.sa_mask);
2505 ret = do_sigaction(sig, &new_sa, &old_sa);
2507 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
2509 #endif /* __ARCH_WANT_SYS_SIGNAL */
2511 #ifdef __ARCH_WANT_SYS_PAUSE
2513 asmlinkage long
2514 sys_pause(void)
2516 current->state = TASK_INTERRUPTIBLE;
2517 schedule();
2518 return -ERESTARTNOHAND;
2521 #endif
2523 #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
2524 asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
2526 sigset_t newset;
2528 /* XXX: Don't preclude handling different sized sigset_t's. */
2529 if (sigsetsize != sizeof(sigset_t))
2530 return -EINVAL;
2532 if (copy_from_user(&newset, unewset, sizeof(newset)))
2533 return -EFAULT;
2534 sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
2536 spin_lock_irq(&current->sighand->siglock);
2537 current->saved_sigmask = current->blocked;
2538 current->blocked = newset;
2539 recalc_sigpending();
2540 spin_unlock_irq(&current->sighand->siglock);
2542 current->state = TASK_INTERRUPTIBLE;
2543 schedule();
2544 set_restore_sigmask();
2545 return -ERESTARTNOHAND;
2547 #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
2549 __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
2551 return NULL;
2554 void __init signals_init(void)
2556 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);