signals: dequeue_signal: don't check SIGNAL_GROUP_EXIT when setting SIGNAL_STOP_DEQUEUED
[linux-2.6/mini2440.git] / kernel / signal.c
blob15f901a26ec78ecc388cd57efb51075d6de5c4de
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 static void __flush_itimer_signals(struct sigpending *pending)
236 sigset_t signal, retain;
237 struct sigqueue *q, *n;
239 signal = pending->signal;
240 sigemptyset(&retain);
242 list_for_each_entry_safe(q, n, &pending->list, list) {
243 int sig = q->info.si_signo;
245 if (likely(q->info.si_code != SI_TIMER)) {
246 sigaddset(&retain, sig);
247 } else {
248 sigdelset(&signal, sig);
249 list_del_init(&q->list);
250 __sigqueue_free(q);
254 sigorsets(&pending->signal, &signal, &retain);
257 void flush_itimer_signals(void)
259 struct task_struct *tsk = current;
260 unsigned long flags;
262 spin_lock_irqsave(&tsk->sighand->siglock, flags);
263 __flush_itimer_signals(&tsk->pending);
264 __flush_itimer_signals(&tsk->signal->shared_pending);
265 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
268 void ignore_signals(struct task_struct *t)
270 int i;
272 for (i = 0; i < _NSIG; ++i)
273 t->sighand->action[i].sa.sa_handler = SIG_IGN;
275 flush_signals(t);
279 * Flush all handlers for a task.
282 void
283 flush_signal_handlers(struct task_struct *t, int force_default)
285 int i;
286 struct k_sigaction *ka = &t->sighand->action[0];
287 for (i = _NSIG ; i != 0 ; i--) {
288 if (force_default || ka->sa.sa_handler != SIG_IGN)
289 ka->sa.sa_handler = SIG_DFL;
290 ka->sa.sa_flags = 0;
291 sigemptyset(&ka->sa.sa_mask);
292 ka++;
296 int unhandled_signal(struct task_struct *tsk, int sig)
298 if (is_global_init(tsk))
299 return 1;
300 if (tsk->ptrace & PT_PTRACED)
301 return 0;
302 return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) ||
303 (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL);
307 /* Notify the system that a driver wants to block all signals for this
308 * process, and wants to be notified if any signals at all were to be
309 * sent/acted upon. If the notifier routine returns non-zero, then the
310 * signal will be acted upon after all. If the notifier routine returns 0,
311 * then then signal will be blocked. Only one block per process is
312 * allowed. priv is a pointer to private data that the notifier routine
313 * can use to determine if the signal should be blocked or not. */
315 void
316 block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
318 unsigned long flags;
320 spin_lock_irqsave(&current->sighand->siglock, flags);
321 current->notifier_mask = mask;
322 current->notifier_data = priv;
323 current->notifier = notifier;
324 spin_unlock_irqrestore(&current->sighand->siglock, flags);
327 /* Notify the system that blocking has ended. */
329 void
330 unblock_all_signals(void)
332 unsigned long flags;
334 spin_lock_irqsave(&current->sighand->siglock, flags);
335 current->notifier = NULL;
336 current->notifier_data = NULL;
337 recalc_sigpending();
338 spin_unlock_irqrestore(&current->sighand->siglock, flags);
341 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
343 struct sigqueue *q, *first = NULL;
346 * Collect the siginfo appropriate to this signal. Check if
347 * there is another siginfo for the same signal.
349 list_for_each_entry(q, &list->list, list) {
350 if (q->info.si_signo == sig) {
351 if (first)
352 goto still_pending;
353 first = q;
357 sigdelset(&list->signal, sig);
359 if (first) {
360 still_pending:
361 list_del_init(&first->list);
362 copy_siginfo(info, &first->info);
363 __sigqueue_free(first);
364 } else {
365 /* Ok, it wasn't in the queue. This must be
366 a fast-pathed signal or we must have been
367 out of queue space. So zero out the info.
369 info->si_signo = sig;
370 info->si_errno = 0;
371 info->si_code = 0;
372 info->si_pid = 0;
373 info->si_uid = 0;
377 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
378 siginfo_t *info)
380 int sig = next_signal(pending, mask);
382 if (sig) {
383 if (current->notifier) {
384 if (sigismember(current->notifier_mask, sig)) {
385 if (!(current->notifier)(current->notifier_data)) {
386 clear_thread_flag(TIF_SIGPENDING);
387 return 0;
392 collect_signal(sig, pending, info);
395 return sig;
399 * Dequeue a signal and return the element to the caller, which is
400 * expected to free it.
402 * All callers have to hold the siglock.
404 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
406 int signr;
408 /* We only dequeue private signals from ourselves, we don't let
409 * signalfd steal them
411 signr = __dequeue_signal(&tsk->pending, mask, info);
412 if (!signr) {
413 signr = __dequeue_signal(&tsk->signal->shared_pending,
414 mask, info);
416 * itimer signal ?
418 * itimers are process shared and we restart periodic
419 * itimers in the signal delivery path to prevent DoS
420 * attacks in the high resolution timer case. This is
421 * compliant with the old way of self restarting
422 * itimers, as the SIGALRM is a legacy signal and only
423 * queued once. Changing the restart behaviour to
424 * restart the timer in the signal dequeue path is
425 * reducing the timer noise on heavy loaded !highres
426 * systems too.
428 if (unlikely(signr == SIGALRM)) {
429 struct hrtimer *tmr = &tsk->signal->real_timer;
431 if (!hrtimer_is_queued(tmr) &&
432 tsk->signal->it_real_incr.tv64 != 0) {
433 hrtimer_forward(tmr, tmr->base->get_time(),
434 tsk->signal->it_real_incr);
435 hrtimer_restart(tmr);
440 recalc_sigpending();
441 if (!signr)
442 return 0;
444 if (unlikely(sig_kernel_stop(signr))) {
446 * Set a marker that we have dequeued a stop signal. Our
447 * caller might release the siglock and then the pending
448 * stop signal it is about to process is no longer in the
449 * pending bitmasks, but must still be cleared by a SIGCONT
450 * (and overruled by a SIGKILL). So those cases clear this
451 * shared flag after we've set it. Note that this flag may
452 * remain set after the signal we return is ignored or
453 * handled. That doesn't matter because its only purpose
454 * is to alert stop-signal processing code when another
455 * processor has come along and cleared the flag.
457 tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
459 if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
461 * Release the siglock to ensure proper locking order
462 * of timer locks outside of siglocks. Note, we leave
463 * irqs disabled here, since the posix-timers code is
464 * about to disable them again anyway.
466 spin_unlock(&tsk->sighand->siglock);
467 do_schedule_next_timer(info);
468 spin_lock(&tsk->sighand->siglock);
470 return signr;
474 * Tell a process that it has a new active signal..
476 * NOTE! we rely on the previous spin_lock to
477 * lock interrupts for us! We can only be called with
478 * "siglock" held, and the local interrupt must
479 * have been disabled when that got acquired!
481 * No need to set need_resched since signal event passing
482 * goes through ->blocked
484 void signal_wake_up(struct task_struct *t, int resume)
486 unsigned int mask;
488 set_tsk_thread_flag(t, TIF_SIGPENDING);
491 * For SIGKILL, we want to wake it up in the stopped/traced/killable
492 * case. We don't check t->state here because there is a race with it
493 * executing another processor and just now entering stopped state.
494 * By using wake_up_state, we ensure the process will wake up and
495 * handle its death signal.
497 mask = TASK_INTERRUPTIBLE;
498 if (resume)
499 mask |= TASK_WAKEKILL;
500 if (!wake_up_state(t, mask))
501 kick_process(t);
505 * Remove signals in mask from the pending set and queue.
506 * Returns 1 if any signals were found.
508 * All callers must be holding the siglock.
510 * This version takes a sigset mask and looks at all signals,
511 * not just those in the first mask word.
513 static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
515 struct sigqueue *q, *n;
516 sigset_t m;
518 sigandsets(&m, mask, &s->signal);
519 if (sigisemptyset(&m))
520 return 0;
522 signandsets(&s->signal, &s->signal, mask);
523 list_for_each_entry_safe(q, n, &s->list, list) {
524 if (sigismember(mask, q->info.si_signo)) {
525 list_del_init(&q->list);
526 __sigqueue_free(q);
529 return 1;
532 * Remove signals in mask from the pending set and queue.
533 * Returns 1 if any signals were found.
535 * All callers must be holding the siglock.
537 static int rm_from_queue(unsigned long mask, struct sigpending *s)
539 struct sigqueue *q, *n;
541 if (!sigtestsetmask(&s->signal, mask))
542 return 0;
544 sigdelsetmask(&s->signal, mask);
545 list_for_each_entry_safe(q, n, &s->list, list) {
546 if (q->info.si_signo < SIGRTMIN &&
547 (mask & sigmask(q->info.si_signo))) {
548 list_del_init(&q->list);
549 __sigqueue_free(q);
552 return 1;
556 * Bad permissions for sending the signal
558 static int check_kill_permission(int sig, struct siginfo *info,
559 struct task_struct *t)
561 struct pid *sid;
562 int error;
564 if (!valid_signal(sig))
565 return -EINVAL;
567 if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
568 return 0;
570 error = audit_signal_info(sig, t); /* Let audit system see the signal */
571 if (error)
572 return error;
574 if ((current->euid ^ t->suid) && (current->euid ^ t->uid) &&
575 (current->uid ^ t->suid) && (current->uid ^ t->uid) &&
576 !capable(CAP_KILL)) {
577 switch (sig) {
578 case SIGCONT:
579 sid = task_session(t);
581 * We don't return the error if sid == NULL. The
582 * task was unhashed, the caller must notice this.
584 if (!sid || sid == task_session(current))
585 break;
586 default:
587 return -EPERM;
591 return security_task_kill(t, info, sig, 0);
594 /* forward decl */
595 static void do_notify_parent_cldstop(struct task_struct *tsk, int why);
598 * Handle magic process-wide effects of stop/continue signals. Unlike
599 * the signal actions, these happen immediately at signal-generation
600 * time regardless of blocking, ignoring, or handling. This does the
601 * actual continuing for SIGCONT, but not the actual stopping for stop
602 * signals. The process stop is done as a signal action for SIG_DFL.
604 * Returns true if the signal should be actually delivered, otherwise
605 * it should be dropped.
607 static int prepare_signal(int sig, struct task_struct *p)
609 struct signal_struct *signal = p->signal;
610 struct task_struct *t;
612 if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) {
614 * The process is in the middle of dying, nothing to do.
616 } else if (sig_kernel_stop(sig)) {
618 * This is a stop signal. Remove SIGCONT from all queues.
620 rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
621 t = p;
622 do {
623 rm_from_queue(sigmask(SIGCONT), &t->pending);
624 } while_each_thread(p, t);
625 } else if (sig == SIGCONT) {
626 unsigned int why;
628 * Remove all stop signals from all queues,
629 * and wake all threads.
631 rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
632 t = p;
633 do {
634 unsigned int state;
635 rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
637 * If there is a handler for SIGCONT, we must make
638 * sure that no thread returns to user mode before
639 * we post the signal, in case it was the only
640 * thread eligible to run the signal handler--then
641 * it must not do anything between resuming and
642 * running the handler. With the TIF_SIGPENDING
643 * flag set, the thread will pause and acquire the
644 * siglock that we hold now and until we've queued
645 * the pending signal.
647 * Wake up the stopped thread _after_ setting
648 * TIF_SIGPENDING
650 state = __TASK_STOPPED;
651 if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
652 set_tsk_thread_flag(t, TIF_SIGPENDING);
653 state |= TASK_INTERRUPTIBLE;
655 wake_up_state(t, state);
656 } while_each_thread(p, t);
659 * Notify the parent with CLD_CONTINUED if we were stopped.
661 * If we were in the middle of a group stop, we pretend it
662 * was already finished, and then continued. Since SIGCHLD
663 * doesn't queue we report only CLD_STOPPED, as if the next
664 * CLD_CONTINUED was dropped.
666 why = 0;
667 if (signal->flags & SIGNAL_STOP_STOPPED)
668 why |= SIGNAL_CLD_CONTINUED;
669 else if (signal->group_stop_count)
670 why |= SIGNAL_CLD_STOPPED;
672 if (why) {
674 * The first thread which returns from finish_stop()
675 * will take ->siglock, notice SIGNAL_CLD_MASK, and
676 * notify its parent. See get_signal_to_deliver().
678 signal->flags = why | SIGNAL_STOP_CONTINUED;
679 signal->group_stop_count = 0;
680 signal->group_exit_code = 0;
681 } else {
683 * We are not stopped, but there could be a stop
684 * signal in the middle of being processed after
685 * being removed from the queue. Clear that too.
687 signal->flags &= ~SIGNAL_STOP_DEQUEUED;
691 return !sig_ignored(p, sig);
695 * Test if P wants to take SIG. After we've checked all threads with this,
696 * it's equivalent to finding no threads not blocking SIG. Any threads not
697 * blocking SIG were ruled out because they are not running and already
698 * have pending signals. Such threads will dequeue from the shared queue
699 * as soon as they're available, so putting the signal on the shared queue
700 * will be equivalent to sending it to one such thread.
702 static inline int wants_signal(int sig, struct task_struct *p)
704 if (sigismember(&p->blocked, sig))
705 return 0;
706 if (p->flags & PF_EXITING)
707 return 0;
708 if (sig == SIGKILL)
709 return 1;
710 if (task_is_stopped_or_traced(p))
711 return 0;
712 return task_curr(p) || !signal_pending(p);
715 static void complete_signal(int sig, struct task_struct *p, int group)
717 struct signal_struct *signal = p->signal;
718 struct task_struct *t;
721 * Now find a thread we can wake up to take the signal off the queue.
723 * If the main thread wants the signal, it gets first crack.
724 * Probably the least surprising to the average bear.
726 if (wants_signal(sig, p))
727 t = p;
728 else if (!group || thread_group_empty(p))
730 * There is just one thread and it does not need to be woken.
731 * It will dequeue unblocked signals before it runs again.
733 return;
734 else {
736 * Otherwise try to find a suitable thread.
738 t = signal->curr_target;
739 while (!wants_signal(sig, t)) {
740 t = next_thread(t);
741 if (t == signal->curr_target)
743 * No thread needs to be woken.
744 * Any eligible threads will see
745 * the signal in the queue soon.
747 return;
749 signal->curr_target = t;
753 * Found a killable thread. If the signal will be fatal,
754 * then start taking the whole group down immediately.
756 if (sig_fatal(p, sig) &&
757 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
758 !sigismember(&t->real_blocked, sig) &&
759 (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
761 * This signal will be fatal to the whole group.
763 if (!sig_kernel_coredump(sig)) {
765 * Start a group exit and wake everybody up.
766 * This way we don't have other threads
767 * running and doing things after a slower
768 * thread has the fatal signal pending.
770 signal->flags = SIGNAL_GROUP_EXIT;
771 signal->group_exit_code = sig;
772 signal->group_stop_count = 0;
773 t = p;
774 do {
775 sigaddset(&t->pending.signal, SIGKILL);
776 signal_wake_up(t, 1);
777 } while_each_thread(p, t);
778 return;
783 * The signal is already in the shared-pending queue.
784 * Tell the chosen thread to wake up and dequeue it.
786 signal_wake_up(t, sig == SIGKILL);
787 return;
790 static inline int legacy_queue(struct sigpending *signals, int sig)
792 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
795 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
796 int group)
798 struct sigpending *pending;
799 struct sigqueue *q;
801 assert_spin_locked(&t->sighand->siglock);
802 if (!prepare_signal(sig, t))
803 return 0;
805 pending = group ? &t->signal->shared_pending : &t->pending;
807 * Short-circuit ignored signals and support queuing
808 * exactly one non-rt signal, so that we can get more
809 * detailed information about the cause of the signal.
811 if (legacy_queue(pending, sig))
812 return 0;
814 * fast-pathed signals for kernel-internal things like SIGSTOP
815 * or SIGKILL.
817 if (info == SEND_SIG_FORCED)
818 goto out_set;
820 /* Real-time signals must be queued if sent by sigqueue, or
821 some other real-time mechanism. It is implementation
822 defined whether kill() does so. We attempt to do so, on
823 the principle of least surprise, but since kill is not
824 allowed to fail with EAGAIN when low on memory we just
825 make sure at least one signal gets delivered and don't
826 pass on the info struct. */
828 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
829 (is_si_special(info) ||
830 info->si_code >= 0)));
831 if (q) {
832 list_add_tail(&q->list, &pending->list);
833 switch ((unsigned long) info) {
834 case (unsigned long) SEND_SIG_NOINFO:
835 q->info.si_signo = sig;
836 q->info.si_errno = 0;
837 q->info.si_code = SI_USER;
838 q->info.si_pid = task_pid_vnr(current);
839 q->info.si_uid = current->uid;
840 break;
841 case (unsigned long) SEND_SIG_PRIV:
842 q->info.si_signo = sig;
843 q->info.si_errno = 0;
844 q->info.si_code = SI_KERNEL;
845 q->info.si_pid = 0;
846 q->info.si_uid = 0;
847 break;
848 default:
849 copy_siginfo(&q->info, info);
850 break;
852 } else if (!is_si_special(info)) {
853 if (sig >= SIGRTMIN && info->si_code != SI_USER)
855 * Queue overflow, abort. We may abort if the signal was rt
856 * and sent by user using something other than kill().
858 return -EAGAIN;
861 out_set:
862 signalfd_notify(t, sig);
863 sigaddset(&pending->signal, sig);
864 complete_signal(sig, t, group);
865 return 0;
868 int print_fatal_signals;
870 static void print_fatal_signal(struct pt_regs *regs, int signr)
872 printk("%s/%d: potentially unexpected fatal signal %d.\n",
873 current->comm, task_pid_nr(current), signr);
875 #if defined(__i386__) && !defined(__arch_um__)
876 printk("code at %08lx: ", regs->ip);
878 int i;
879 for (i = 0; i < 16; i++) {
880 unsigned char insn;
882 __get_user(insn, (unsigned char *)(regs->ip + i));
883 printk("%02x ", insn);
886 #endif
887 printk("\n");
888 show_regs(regs);
891 static int __init setup_print_fatal_signals(char *str)
893 get_option (&str, &print_fatal_signals);
895 return 1;
898 __setup("print-fatal-signals=", setup_print_fatal_signals);
901 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
903 return send_signal(sig, info, p, 1);
906 static int
907 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
909 return send_signal(sig, info, t, 0);
913 * Force a signal that the process can't ignore: if necessary
914 * we unblock the signal and change any SIG_IGN to SIG_DFL.
916 * Note: If we unblock the signal, we always reset it to SIG_DFL,
917 * since we do not want to have a signal handler that was blocked
918 * be invoked when user space had explicitly blocked it.
920 * We don't want to have recursive SIGSEGV's etc, for example,
921 * that is why we also clear SIGNAL_UNKILLABLE.
924 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
926 unsigned long int flags;
927 int ret, blocked, ignored;
928 struct k_sigaction *action;
930 spin_lock_irqsave(&t->sighand->siglock, flags);
931 action = &t->sighand->action[sig-1];
932 ignored = action->sa.sa_handler == SIG_IGN;
933 blocked = sigismember(&t->blocked, sig);
934 if (blocked || ignored) {
935 action->sa.sa_handler = SIG_DFL;
936 if (blocked) {
937 sigdelset(&t->blocked, sig);
938 recalc_sigpending_and_wake(t);
941 if (action->sa.sa_handler == SIG_DFL)
942 t->signal->flags &= ~SIGNAL_UNKILLABLE;
943 ret = specific_send_sig_info(sig, info, t);
944 spin_unlock_irqrestore(&t->sighand->siglock, flags);
946 return ret;
949 void
950 force_sig_specific(int sig, struct task_struct *t)
952 force_sig_info(sig, SEND_SIG_FORCED, t);
956 * Nuke all other threads in the group.
958 void zap_other_threads(struct task_struct *p)
960 struct task_struct *t;
962 p->signal->group_stop_count = 0;
964 for (t = next_thread(p); t != p; t = next_thread(t)) {
966 * Don't bother with already dead threads
968 if (t->exit_state)
969 continue;
971 /* SIGKILL will be handled before any pending SIGSTOP */
972 sigaddset(&t->pending.signal, SIGKILL);
973 signal_wake_up(t, 1);
977 int __fatal_signal_pending(struct task_struct *tsk)
979 return sigismember(&tsk->pending.signal, SIGKILL);
981 EXPORT_SYMBOL(__fatal_signal_pending);
983 struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
985 struct sighand_struct *sighand;
987 rcu_read_lock();
988 for (;;) {
989 sighand = rcu_dereference(tsk->sighand);
990 if (unlikely(sighand == NULL))
991 break;
993 spin_lock_irqsave(&sighand->siglock, *flags);
994 if (likely(sighand == tsk->sighand))
995 break;
996 spin_unlock_irqrestore(&sighand->siglock, *flags);
998 rcu_read_unlock();
1000 return sighand;
1003 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1005 unsigned long flags;
1006 int ret;
1008 ret = check_kill_permission(sig, info, p);
1010 if (!ret && sig) {
1011 ret = -ESRCH;
1012 if (lock_task_sighand(p, &flags)) {
1013 ret = __group_send_sig_info(sig, info, p);
1014 unlock_task_sighand(p, &flags);
1018 return ret;
1022 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1023 * control characters do (^C, ^Z etc)
1026 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1028 struct task_struct *p = NULL;
1029 int retval, success;
1031 success = 0;
1032 retval = -ESRCH;
1033 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1034 int err = group_send_sig_info(sig, info, p);
1035 success |= !err;
1036 retval = err;
1037 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1038 return success ? 0 : retval;
1041 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1043 int error = -ESRCH;
1044 struct task_struct *p;
1046 rcu_read_lock();
1047 retry:
1048 p = pid_task(pid, PIDTYPE_PID);
1049 if (p) {
1050 error = group_send_sig_info(sig, info, p);
1051 if (unlikely(error == -ESRCH))
1053 * The task was unhashed in between, try again.
1054 * If it is dead, pid_task() will return NULL,
1055 * if we race with de_thread() it will find the
1056 * new leader.
1058 goto retry;
1060 rcu_read_unlock();
1062 return error;
1066 kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1068 int error;
1069 rcu_read_lock();
1070 error = kill_pid_info(sig, info, find_vpid(pid));
1071 rcu_read_unlock();
1072 return error;
1075 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1076 int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
1077 uid_t uid, uid_t euid, u32 secid)
1079 int ret = -EINVAL;
1080 struct task_struct *p;
1082 if (!valid_signal(sig))
1083 return ret;
1085 read_lock(&tasklist_lock);
1086 p = pid_task(pid, PIDTYPE_PID);
1087 if (!p) {
1088 ret = -ESRCH;
1089 goto out_unlock;
1091 if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
1092 && (euid != p->suid) && (euid != p->uid)
1093 && (uid != p->suid) && (uid != p->uid)) {
1094 ret = -EPERM;
1095 goto out_unlock;
1097 ret = security_task_kill(p, info, sig, secid);
1098 if (ret)
1099 goto out_unlock;
1100 if (sig && p->sighand) {
1101 unsigned long flags;
1102 spin_lock_irqsave(&p->sighand->siglock, flags);
1103 ret = __group_send_sig_info(sig, info, p);
1104 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1106 out_unlock:
1107 read_unlock(&tasklist_lock);
1108 return ret;
1110 EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
1113 * kill_something_info() interprets pid in interesting ways just like kill(2).
1115 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1116 * is probably wrong. Should make it like BSD or SYSV.
1119 static int kill_something_info(int sig, struct siginfo *info, int pid)
1121 int ret;
1123 if (pid > 0) {
1124 rcu_read_lock();
1125 ret = kill_pid_info(sig, info, find_vpid(pid));
1126 rcu_read_unlock();
1127 return ret;
1130 read_lock(&tasklist_lock);
1131 if (pid != -1) {
1132 ret = __kill_pgrp_info(sig, info,
1133 pid ? find_vpid(-pid) : task_pgrp(current));
1134 } else {
1135 int retval = 0, count = 0;
1136 struct task_struct * p;
1138 for_each_process(p) {
1139 if (p->pid > 1 && !same_thread_group(p, current)) {
1140 int err = group_send_sig_info(sig, info, p);
1141 ++count;
1142 if (err != -EPERM)
1143 retval = err;
1146 ret = count ? retval : -ESRCH;
1148 read_unlock(&tasklist_lock);
1150 return ret;
1154 * These are for backward compatibility with the rest of the kernel source.
1158 * The caller must ensure the task can't exit.
1161 send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1163 int ret;
1164 unsigned long flags;
1167 * Make sure legacy kernel users don't send in bad values
1168 * (normal paths check this in check_kill_permission).
1170 if (!valid_signal(sig))
1171 return -EINVAL;
1173 spin_lock_irqsave(&p->sighand->siglock, flags);
1174 ret = specific_send_sig_info(sig, info, p);
1175 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1176 return ret;
1179 #define __si_special(priv) \
1180 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1183 send_sig(int sig, struct task_struct *p, int priv)
1185 return send_sig_info(sig, __si_special(priv), p);
1188 void
1189 force_sig(int sig, struct task_struct *p)
1191 force_sig_info(sig, SEND_SIG_PRIV, p);
1195 * When things go south during signal handling, we
1196 * will force a SIGSEGV. And if the signal that caused
1197 * the problem was already a SIGSEGV, we'll want to
1198 * make sure we don't even try to deliver the signal..
1201 force_sigsegv(int sig, struct task_struct *p)
1203 if (sig == SIGSEGV) {
1204 unsigned long flags;
1205 spin_lock_irqsave(&p->sighand->siglock, flags);
1206 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1207 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1209 force_sig(SIGSEGV, p);
1210 return 0;
1213 int kill_pgrp(struct pid *pid, int sig, int priv)
1215 int ret;
1217 read_lock(&tasklist_lock);
1218 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1219 read_unlock(&tasklist_lock);
1221 return ret;
1223 EXPORT_SYMBOL(kill_pgrp);
1225 int kill_pid(struct pid *pid, int sig, int priv)
1227 return kill_pid_info(sig, __si_special(priv), pid);
1229 EXPORT_SYMBOL(kill_pid);
1232 kill_proc(pid_t pid, int sig, int priv)
1234 int ret;
1236 rcu_read_lock();
1237 ret = kill_pid_info(sig, __si_special(priv), find_pid(pid));
1238 rcu_read_unlock();
1239 return ret;
1243 * These functions support sending signals using preallocated sigqueue
1244 * structures. This is needed "because realtime applications cannot
1245 * afford to lose notifications of asynchronous events, like timer
1246 * expirations or I/O completions". In the case of Posix Timers
1247 * we allocate the sigqueue structure from the timer_create. If this
1248 * allocation fails we are able to report the failure to the application
1249 * with an EAGAIN error.
1252 struct sigqueue *sigqueue_alloc(void)
1254 struct sigqueue *q;
1256 if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
1257 q->flags |= SIGQUEUE_PREALLOC;
1258 return(q);
1261 void sigqueue_free(struct sigqueue *q)
1263 unsigned long flags;
1264 spinlock_t *lock = &current->sighand->siglock;
1266 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1268 * We must hold ->siglock while testing q->list
1269 * to serialize with collect_signal() or with
1270 * __exit_signal()->flush_sigqueue().
1272 spin_lock_irqsave(lock, flags);
1273 q->flags &= ~SIGQUEUE_PREALLOC;
1275 * If it is queued it will be freed when dequeued,
1276 * like the "regular" sigqueue.
1278 if (!list_empty(&q->list))
1279 q = NULL;
1280 spin_unlock_irqrestore(lock, flags);
1282 if (q)
1283 __sigqueue_free(q);
1286 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1288 int sig = q->info.si_signo;
1289 struct sigpending *pending;
1290 unsigned long flags;
1291 int ret;
1293 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1295 ret = -1;
1296 if (!likely(lock_task_sighand(t, &flags)))
1297 goto ret;
1299 ret = 1; /* the signal is ignored */
1300 if (!prepare_signal(sig, t))
1301 goto out;
1303 ret = 0;
1304 if (unlikely(!list_empty(&q->list))) {
1306 * If an SI_TIMER entry is already queue just increment
1307 * the overrun count.
1309 BUG_ON(q->info.si_code != SI_TIMER);
1310 q->info.si_overrun++;
1311 goto out;
1314 signalfd_notify(t, sig);
1315 pending = group ? &t->signal->shared_pending : &t->pending;
1316 list_add_tail(&q->list, &pending->list);
1317 sigaddset(&pending->signal, sig);
1318 complete_signal(sig, t, group);
1319 out:
1320 unlock_task_sighand(t, &flags);
1321 ret:
1322 return ret;
1326 * Wake up any threads in the parent blocked in wait* syscalls.
1328 static inline void __wake_up_parent(struct task_struct *p,
1329 struct task_struct *parent)
1331 wake_up_interruptible_sync(&parent->signal->wait_chldexit);
1335 * Let a parent know about the death of a child.
1336 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1339 void do_notify_parent(struct task_struct *tsk, int sig)
1341 struct siginfo info;
1342 unsigned long flags;
1343 struct sighand_struct *psig;
1345 BUG_ON(sig == -1);
1347 /* do_notify_parent_cldstop should have been called instead. */
1348 BUG_ON(task_is_stopped_or_traced(tsk));
1350 BUG_ON(!tsk->ptrace &&
1351 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1353 info.si_signo = sig;
1354 info.si_errno = 0;
1356 * we are under tasklist_lock here so our parent is tied to
1357 * us and cannot exit and release its namespace.
1359 * the only it can is to switch its nsproxy with sys_unshare,
1360 * bu uncharing pid namespaces is not allowed, so we'll always
1361 * see relevant namespace
1363 * write_lock() currently calls preempt_disable() which is the
1364 * same as rcu_read_lock(), but according to Oleg, this is not
1365 * correct to rely on this
1367 rcu_read_lock();
1368 info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
1369 rcu_read_unlock();
1371 info.si_uid = tsk->uid;
1373 /* FIXME: find out whether or not this is supposed to be c*time. */
1374 info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime,
1375 tsk->signal->utime));
1376 info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime,
1377 tsk->signal->stime));
1379 info.si_status = tsk->exit_code & 0x7f;
1380 if (tsk->exit_code & 0x80)
1381 info.si_code = CLD_DUMPED;
1382 else if (tsk->exit_code & 0x7f)
1383 info.si_code = CLD_KILLED;
1384 else {
1385 info.si_code = CLD_EXITED;
1386 info.si_status = tsk->exit_code >> 8;
1389 psig = tsk->parent->sighand;
1390 spin_lock_irqsave(&psig->siglock, flags);
1391 if (!tsk->ptrace && sig == SIGCHLD &&
1392 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1393 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1395 * We are exiting and our parent doesn't care. POSIX.1
1396 * defines special semantics for setting SIGCHLD to SIG_IGN
1397 * or setting the SA_NOCLDWAIT flag: we should be reaped
1398 * automatically and not left for our parent's wait4 call.
1399 * Rather than having the parent do it as a magic kind of
1400 * signal handler, we just set this to tell do_exit that we
1401 * can be cleaned up without becoming a zombie. Note that
1402 * we still call __wake_up_parent in this case, because a
1403 * blocked sys_wait4 might now return -ECHILD.
1405 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1406 * is implementation-defined: we do (if you don't want
1407 * it, just use SIG_IGN instead).
1409 tsk->exit_signal = -1;
1410 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1411 sig = 0;
1413 if (valid_signal(sig) && sig > 0)
1414 __group_send_sig_info(sig, &info, tsk->parent);
1415 __wake_up_parent(tsk, tsk->parent);
1416 spin_unlock_irqrestore(&psig->siglock, flags);
1419 static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
1421 struct siginfo info;
1422 unsigned long flags;
1423 struct task_struct *parent;
1424 struct sighand_struct *sighand;
1426 if (tsk->ptrace & PT_PTRACED)
1427 parent = tsk->parent;
1428 else {
1429 tsk = tsk->group_leader;
1430 parent = tsk->real_parent;
1433 info.si_signo = SIGCHLD;
1434 info.si_errno = 0;
1436 * see comment in do_notify_parent() abot the following 3 lines
1438 rcu_read_lock();
1439 info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
1440 rcu_read_unlock();
1442 info.si_uid = tsk->uid;
1444 /* FIXME: find out whether or not this is supposed to be c*time. */
1445 info.si_utime = cputime_to_jiffies(tsk->utime);
1446 info.si_stime = cputime_to_jiffies(tsk->stime);
1448 info.si_code = why;
1449 switch (why) {
1450 case CLD_CONTINUED:
1451 info.si_status = SIGCONT;
1452 break;
1453 case CLD_STOPPED:
1454 info.si_status = tsk->signal->group_exit_code & 0x7f;
1455 break;
1456 case CLD_TRAPPED:
1457 info.si_status = tsk->exit_code & 0x7f;
1458 break;
1459 default:
1460 BUG();
1463 sighand = parent->sighand;
1464 spin_lock_irqsave(&sighand->siglock, flags);
1465 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1466 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1467 __group_send_sig_info(SIGCHLD, &info, parent);
1469 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1471 __wake_up_parent(tsk, parent);
1472 spin_unlock_irqrestore(&sighand->siglock, flags);
1475 static inline int may_ptrace_stop(void)
1477 if (!likely(current->ptrace & PT_PTRACED))
1478 return 0;
1480 * Are we in the middle of do_coredump?
1481 * If so and our tracer is also part of the coredump stopping
1482 * is a deadlock situation, and pointless because our tracer
1483 * is dead so don't allow us to stop.
1484 * If SIGKILL was already sent before the caller unlocked
1485 * ->siglock we must see ->core_waiters != 0. Otherwise it
1486 * is safe to enter schedule().
1488 if (unlikely(current->mm->core_waiters) &&
1489 unlikely(current->mm == current->parent->mm))
1490 return 0;
1492 return 1;
1496 * Return nonzero if there is a SIGKILL that should be waking us up.
1497 * Called with the siglock held.
1499 static int sigkill_pending(struct task_struct *tsk)
1501 return ((sigismember(&tsk->pending.signal, SIGKILL) ||
1502 sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) &&
1503 !unlikely(sigismember(&tsk->blocked, SIGKILL)));
1507 * This must be called with current->sighand->siglock held.
1509 * This should be the path for all ptrace stops.
1510 * We always set current->last_siginfo while stopped here.
1511 * That makes it a way to test a stopped process for
1512 * being ptrace-stopped vs being job-control-stopped.
1514 * If we actually decide not to stop at all because the tracer
1515 * is gone, we keep current->exit_code unless clear_code.
1517 static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
1519 int killed = 0;
1521 if (arch_ptrace_stop_needed(exit_code, info)) {
1523 * The arch code has something special to do before a
1524 * ptrace stop. This is allowed to block, e.g. for faults
1525 * on user stack pages. We can't keep the siglock while
1526 * calling arch_ptrace_stop, so we must release it now.
1527 * To preserve proper semantics, we must do this before
1528 * any signal bookkeeping like checking group_stop_count.
1529 * Meanwhile, a SIGKILL could come in before we retake the
1530 * siglock. That must prevent us from sleeping in TASK_TRACED.
1531 * So after regaining the lock, we must check for SIGKILL.
1533 spin_unlock_irq(&current->sighand->siglock);
1534 arch_ptrace_stop(exit_code, info);
1535 spin_lock_irq(&current->sighand->siglock);
1536 killed = sigkill_pending(current);
1540 * If there is a group stop in progress,
1541 * we must participate in the bookkeeping.
1543 if (current->signal->group_stop_count > 0)
1544 --current->signal->group_stop_count;
1546 current->last_siginfo = info;
1547 current->exit_code = exit_code;
1549 /* Let the debugger run. */
1550 __set_current_state(TASK_TRACED);
1551 spin_unlock_irq(&current->sighand->siglock);
1552 read_lock(&tasklist_lock);
1553 if (!unlikely(killed) && may_ptrace_stop()) {
1554 do_notify_parent_cldstop(current, CLD_TRAPPED);
1555 read_unlock(&tasklist_lock);
1556 schedule();
1557 } else {
1559 * By the time we got the lock, our tracer went away.
1560 * Don't drop the lock yet, another tracer may come.
1562 __set_current_state(TASK_RUNNING);
1563 if (clear_code)
1564 current->exit_code = 0;
1565 read_unlock(&tasklist_lock);
1569 * While in TASK_TRACED, we were considered "frozen enough".
1570 * Now that we woke up, it's crucial if we're supposed to be
1571 * frozen that we freeze now before running anything substantial.
1573 try_to_freeze();
1576 * We are back. Now reacquire the siglock before touching
1577 * last_siginfo, so that we are sure to have synchronized with
1578 * any signal-sending on another CPU that wants to examine it.
1580 spin_lock_irq(&current->sighand->siglock);
1581 current->last_siginfo = NULL;
1584 * Queued signals ignored us while we were stopped for tracing.
1585 * So check for any that we should take before resuming user mode.
1586 * This sets TIF_SIGPENDING, but never clears it.
1588 recalc_sigpending_tsk(current);
1591 void ptrace_notify(int exit_code)
1593 siginfo_t info;
1595 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1597 memset(&info, 0, sizeof info);
1598 info.si_signo = SIGTRAP;
1599 info.si_code = exit_code;
1600 info.si_pid = task_pid_vnr(current);
1601 info.si_uid = current->uid;
1603 /* Let the debugger run. */
1604 spin_lock_irq(&current->sighand->siglock);
1605 ptrace_stop(exit_code, 1, &info);
1606 spin_unlock_irq(&current->sighand->siglock);
1609 static void
1610 finish_stop(int stop_count)
1613 * If there are no other threads in the group, or if there is
1614 * a group stop in progress and we are the last to stop,
1615 * report to the parent. When ptraced, every thread reports itself.
1617 if (stop_count == 0 || (current->ptrace & PT_PTRACED)) {
1618 read_lock(&tasklist_lock);
1619 do_notify_parent_cldstop(current, CLD_STOPPED);
1620 read_unlock(&tasklist_lock);
1623 do {
1624 schedule();
1625 } while (try_to_freeze());
1627 * Now we don't run again until continued.
1629 current->exit_code = 0;
1633 * This performs the stopping for SIGSTOP and other stop signals.
1634 * We have to stop all threads in the thread group.
1635 * Returns nonzero if we've actually stopped and released the siglock.
1636 * Returns zero if we didn't stop and still hold the siglock.
1638 static int do_signal_stop(int signr)
1640 struct signal_struct *sig = current->signal;
1641 int stop_count;
1643 if (sig->group_stop_count > 0) {
1645 * There is a group stop in progress. We don't need to
1646 * start another one.
1648 stop_count = --sig->group_stop_count;
1649 } else {
1650 struct task_struct *t;
1652 if (unlikely((sig->flags & (SIGNAL_STOP_DEQUEUED | SIGNAL_UNKILLABLE))
1653 != SIGNAL_STOP_DEQUEUED) ||
1654 unlikely(signal_group_exit(sig)))
1655 return 0;
1657 * There is no group stop already in progress.
1658 * We must initiate one now.
1660 sig->group_exit_code = signr;
1662 stop_count = 0;
1663 for (t = next_thread(current); t != current; t = next_thread(t))
1665 * Setting state to TASK_STOPPED for a group
1666 * stop is always done with the siglock held,
1667 * so this check has no races.
1669 if (!(t->flags & PF_EXITING) &&
1670 !task_is_stopped_or_traced(t)) {
1671 stop_count++;
1672 signal_wake_up(t, 0);
1674 sig->group_stop_count = stop_count;
1677 if (stop_count == 0)
1678 sig->flags = SIGNAL_STOP_STOPPED;
1679 current->exit_code = sig->group_exit_code;
1680 __set_current_state(TASK_STOPPED);
1682 spin_unlock_irq(&current->sighand->siglock);
1683 finish_stop(stop_count);
1684 return 1;
1687 static int ptrace_signal(int signr, siginfo_t *info,
1688 struct pt_regs *regs, void *cookie)
1690 if (!(current->ptrace & PT_PTRACED))
1691 return signr;
1693 ptrace_signal_deliver(regs, cookie);
1695 /* Let the debugger run. */
1696 ptrace_stop(signr, 0, info);
1698 /* We're back. Did the debugger cancel the sig? */
1699 signr = current->exit_code;
1700 if (signr == 0)
1701 return signr;
1703 current->exit_code = 0;
1705 /* Update the siginfo structure if the signal has
1706 changed. If the debugger wanted something
1707 specific in the siginfo structure then it should
1708 have updated *info via PTRACE_SETSIGINFO. */
1709 if (signr != info->si_signo) {
1710 info->si_signo = signr;
1711 info->si_errno = 0;
1712 info->si_code = SI_USER;
1713 info->si_pid = task_pid_vnr(current->parent);
1714 info->si_uid = current->parent->uid;
1717 /* If the (new) signal is now blocked, requeue it. */
1718 if (sigismember(&current->blocked, signr)) {
1719 specific_send_sig_info(signr, info, current);
1720 signr = 0;
1723 return signr;
1726 int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
1727 struct pt_regs *regs, void *cookie)
1729 struct sighand_struct *sighand = current->sighand;
1730 struct signal_struct *signal = current->signal;
1731 int signr;
1733 relock:
1735 * We'll jump back here after any time we were stopped in TASK_STOPPED.
1736 * While in TASK_STOPPED, we were considered "frozen enough".
1737 * Now that we woke up, it's crucial if we're supposed to be
1738 * frozen that we freeze now before running anything substantial.
1740 try_to_freeze();
1742 spin_lock_irq(&sighand->siglock);
1744 * Every stopped thread goes here after wakeup. Check to see if
1745 * we should notify the parent, prepare_signal(SIGCONT) encodes
1746 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
1748 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
1749 int why = (signal->flags & SIGNAL_STOP_CONTINUED)
1750 ? CLD_CONTINUED : CLD_STOPPED;
1751 signal->flags &= ~SIGNAL_CLD_MASK;
1752 spin_unlock_irq(&sighand->siglock);
1754 read_lock(&tasklist_lock);
1755 do_notify_parent_cldstop(current->group_leader, why);
1756 read_unlock(&tasklist_lock);
1757 goto relock;
1760 for (;;) {
1761 struct k_sigaction *ka;
1763 if (unlikely(signal->group_stop_count > 0) &&
1764 do_signal_stop(0))
1765 goto relock;
1767 signr = dequeue_signal(current, &current->blocked, info);
1768 if (!signr)
1769 break; /* will return 0 */
1771 if (signr != SIGKILL) {
1772 signr = ptrace_signal(signr, info, regs, cookie);
1773 if (!signr)
1774 continue;
1777 ka = &sighand->action[signr-1];
1778 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
1779 continue;
1780 if (ka->sa.sa_handler != SIG_DFL) {
1781 /* Run the handler. */
1782 *return_ka = *ka;
1784 if (ka->sa.sa_flags & SA_ONESHOT)
1785 ka->sa.sa_handler = SIG_DFL;
1787 break; /* will return non-zero "signr" value */
1791 * Now we are doing the default action for this signal.
1793 if (sig_kernel_ignore(signr)) /* Default is nothing. */
1794 continue;
1797 * Global init gets no signals it doesn't want.
1799 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
1800 !signal_group_exit(signal))
1801 continue;
1803 if (sig_kernel_stop(signr)) {
1805 * The default action is to stop all threads in
1806 * the thread group. The job control signals
1807 * do nothing in an orphaned pgrp, but SIGSTOP
1808 * always works. Note that siglock needs to be
1809 * dropped during the call to is_orphaned_pgrp()
1810 * because of lock ordering with tasklist_lock.
1811 * This allows an intervening SIGCONT to be posted.
1812 * We need to check for that and bail out if necessary.
1814 if (signr != SIGSTOP) {
1815 spin_unlock_irq(&sighand->siglock);
1817 /* signals can be posted during this window */
1819 if (is_current_pgrp_orphaned())
1820 goto relock;
1822 spin_lock_irq(&sighand->siglock);
1825 if (likely(do_signal_stop(signr))) {
1826 /* It released the siglock. */
1827 goto relock;
1831 * We didn't actually stop, due to a race
1832 * with SIGCONT or something like that.
1834 continue;
1837 spin_unlock_irq(&sighand->siglock);
1840 * Anything else is fatal, maybe with a core dump.
1842 current->flags |= PF_SIGNALED;
1844 if (sig_kernel_coredump(signr)) {
1845 if (print_fatal_signals)
1846 print_fatal_signal(regs, signr);
1848 * If it was able to dump core, this kills all
1849 * other threads in the group and synchronizes with
1850 * their demise. If we lost the race with another
1851 * thread getting here, it set group_exit_code
1852 * first and our do_group_exit call below will use
1853 * that value and ignore the one we pass it.
1855 do_coredump((long)signr, signr, regs);
1859 * Death signals, no core dump.
1861 do_group_exit(signr);
1862 /* NOTREACHED */
1864 spin_unlock_irq(&sighand->siglock);
1865 return signr;
1868 void exit_signals(struct task_struct *tsk)
1870 int group_stop = 0;
1871 struct task_struct *t;
1873 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
1874 tsk->flags |= PF_EXITING;
1875 return;
1878 spin_lock_irq(&tsk->sighand->siglock);
1880 * From now this task is not visible for group-wide signals,
1881 * see wants_signal(), do_signal_stop().
1883 tsk->flags |= PF_EXITING;
1884 if (!signal_pending(tsk))
1885 goto out;
1887 /* It could be that __group_complete_signal() choose us to
1888 * notify about group-wide signal. Another thread should be
1889 * woken now to take the signal since we will not.
1891 for (t = tsk; (t = next_thread(t)) != tsk; )
1892 if (!signal_pending(t) && !(t->flags & PF_EXITING))
1893 recalc_sigpending_and_wake(t);
1895 if (unlikely(tsk->signal->group_stop_count) &&
1896 !--tsk->signal->group_stop_count) {
1897 tsk->signal->flags = SIGNAL_STOP_STOPPED;
1898 group_stop = 1;
1900 out:
1901 spin_unlock_irq(&tsk->sighand->siglock);
1903 if (unlikely(group_stop)) {
1904 read_lock(&tasklist_lock);
1905 do_notify_parent_cldstop(tsk, CLD_STOPPED);
1906 read_unlock(&tasklist_lock);
1910 EXPORT_SYMBOL(recalc_sigpending);
1911 EXPORT_SYMBOL_GPL(dequeue_signal);
1912 EXPORT_SYMBOL(flush_signals);
1913 EXPORT_SYMBOL(force_sig);
1914 EXPORT_SYMBOL(kill_proc);
1915 EXPORT_SYMBOL(ptrace_notify);
1916 EXPORT_SYMBOL(send_sig);
1917 EXPORT_SYMBOL(send_sig_info);
1918 EXPORT_SYMBOL(sigprocmask);
1919 EXPORT_SYMBOL(block_all_signals);
1920 EXPORT_SYMBOL(unblock_all_signals);
1924 * System call entry points.
1927 asmlinkage long sys_restart_syscall(void)
1929 struct restart_block *restart = &current_thread_info()->restart_block;
1930 return restart->fn(restart);
1933 long do_no_restart_syscall(struct restart_block *param)
1935 return -EINTR;
1939 * We don't need to get the kernel lock - this is all local to this
1940 * particular thread.. (and that's good, because this is _heavily_
1941 * used by various programs)
1945 * This is also useful for kernel threads that want to temporarily
1946 * (or permanently) block certain signals.
1948 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
1949 * interface happily blocks "unblockable" signals like SIGKILL
1950 * and friends.
1952 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
1954 int error;
1956 spin_lock_irq(&current->sighand->siglock);
1957 if (oldset)
1958 *oldset = current->blocked;
1960 error = 0;
1961 switch (how) {
1962 case SIG_BLOCK:
1963 sigorsets(&current->blocked, &current->blocked, set);
1964 break;
1965 case SIG_UNBLOCK:
1966 signandsets(&current->blocked, &current->blocked, set);
1967 break;
1968 case SIG_SETMASK:
1969 current->blocked = *set;
1970 break;
1971 default:
1972 error = -EINVAL;
1974 recalc_sigpending();
1975 spin_unlock_irq(&current->sighand->siglock);
1977 return error;
1980 asmlinkage long
1981 sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize)
1983 int error = -EINVAL;
1984 sigset_t old_set, new_set;
1986 /* XXX: Don't preclude handling different sized sigset_t's. */
1987 if (sigsetsize != sizeof(sigset_t))
1988 goto out;
1990 if (set) {
1991 error = -EFAULT;
1992 if (copy_from_user(&new_set, set, sizeof(*set)))
1993 goto out;
1994 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1996 error = sigprocmask(how, &new_set, &old_set);
1997 if (error)
1998 goto out;
1999 if (oset)
2000 goto set_old;
2001 } else if (oset) {
2002 spin_lock_irq(&current->sighand->siglock);
2003 old_set = current->blocked;
2004 spin_unlock_irq(&current->sighand->siglock);
2006 set_old:
2007 error = -EFAULT;
2008 if (copy_to_user(oset, &old_set, sizeof(*oset)))
2009 goto out;
2011 error = 0;
2012 out:
2013 return error;
2016 long do_sigpending(void __user *set, unsigned long sigsetsize)
2018 long error = -EINVAL;
2019 sigset_t pending;
2021 if (sigsetsize > sizeof(sigset_t))
2022 goto out;
2024 spin_lock_irq(&current->sighand->siglock);
2025 sigorsets(&pending, &current->pending.signal,
2026 &current->signal->shared_pending.signal);
2027 spin_unlock_irq(&current->sighand->siglock);
2029 /* Outside the lock because only this thread touches it. */
2030 sigandsets(&pending, &current->blocked, &pending);
2032 error = -EFAULT;
2033 if (!copy_to_user(set, &pending, sigsetsize))
2034 error = 0;
2036 out:
2037 return error;
2040 asmlinkage long
2041 sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize)
2043 return do_sigpending(set, sigsetsize);
2046 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2048 int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
2050 int err;
2052 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2053 return -EFAULT;
2054 if (from->si_code < 0)
2055 return __copy_to_user(to, from, sizeof(siginfo_t))
2056 ? -EFAULT : 0;
2058 * If you change siginfo_t structure, please be sure
2059 * this code is fixed accordingly.
2060 * Please remember to update the signalfd_copyinfo() function
2061 * inside fs/signalfd.c too, in case siginfo_t changes.
2062 * It should never copy any pad contained in the structure
2063 * to avoid security leaks, but must copy the generic
2064 * 3 ints plus the relevant union member.
2066 err = __put_user(from->si_signo, &to->si_signo);
2067 err |= __put_user(from->si_errno, &to->si_errno);
2068 err |= __put_user((short)from->si_code, &to->si_code);
2069 switch (from->si_code & __SI_MASK) {
2070 case __SI_KILL:
2071 err |= __put_user(from->si_pid, &to->si_pid);
2072 err |= __put_user(from->si_uid, &to->si_uid);
2073 break;
2074 case __SI_TIMER:
2075 err |= __put_user(from->si_tid, &to->si_tid);
2076 err |= __put_user(from->si_overrun, &to->si_overrun);
2077 err |= __put_user(from->si_ptr, &to->si_ptr);
2078 break;
2079 case __SI_POLL:
2080 err |= __put_user(from->si_band, &to->si_band);
2081 err |= __put_user(from->si_fd, &to->si_fd);
2082 break;
2083 case __SI_FAULT:
2084 err |= __put_user(from->si_addr, &to->si_addr);
2085 #ifdef __ARCH_SI_TRAPNO
2086 err |= __put_user(from->si_trapno, &to->si_trapno);
2087 #endif
2088 break;
2089 case __SI_CHLD:
2090 err |= __put_user(from->si_pid, &to->si_pid);
2091 err |= __put_user(from->si_uid, &to->si_uid);
2092 err |= __put_user(from->si_status, &to->si_status);
2093 err |= __put_user(from->si_utime, &to->si_utime);
2094 err |= __put_user(from->si_stime, &to->si_stime);
2095 break;
2096 case __SI_RT: /* This is not generated by the kernel as of now. */
2097 case __SI_MESGQ: /* But this is */
2098 err |= __put_user(from->si_pid, &to->si_pid);
2099 err |= __put_user(from->si_uid, &to->si_uid);
2100 err |= __put_user(from->si_ptr, &to->si_ptr);
2101 break;
2102 default: /* this is just in case for now ... */
2103 err |= __put_user(from->si_pid, &to->si_pid);
2104 err |= __put_user(from->si_uid, &to->si_uid);
2105 break;
2107 return err;
2110 #endif
2112 asmlinkage long
2113 sys_rt_sigtimedwait(const sigset_t __user *uthese,
2114 siginfo_t __user *uinfo,
2115 const struct timespec __user *uts,
2116 size_t sigsetsize)
2118 int ret, sig;
2119 sigset_t these;
2120 struct timespec ts;
2121 siginfo_t info;
2122 long timeout = 0;
2124 /* XXX: Don't preclude handling different sized sigset_t's. */
2125 if (sigsetsize != sizeof(sigset_t))
2126 return -EINVAL;
2128 if (copy_from_user(&these, uthese, sizeof(these)))
2129 return -EFAULT;
2132 * Invert the set of allowed signals to get those we
2133 * want to block.
2135 sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));
2136 signotset(&these);
2138 if (uts) {
2139 if (copy_from_user(&ts, uts, sizeof(ts)))
2140 return -EFAULT;
2141 if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0
2142 || ts.tv_sec < 0)
2143 return -EINVAL;
2146 spin_lock_irq(&current->sighand->siglock);
2147 sig = dequeue_signal(current, &these, &info);
2148 if (!sig) {
2149 timeout = MAX_SCHEDULE_TIMEOUT;
2150 if (uts)
2151 timeout = (timespec_to_jiffies(&ts)
2152 + (ts.tv_sec || ts.tv_nsec));
2154 if (timeout) {
2155 /* None ready -- temporarily unblock those we're
2156 * interested while we are sleeping in so that we'll
2157 * be awakened when they arrive. */
2158 current->real_blocked = current->blocked;
2159 sigandsets(&current->blocked, &current->blocked, &these);
2160 recalc_sigpending();
2161 spin_unlock_irq(&current->sighand->siglock);
2163 timeout = schedule_timeout_interruptible(timeout);
2165 spin_lock_irq(&current->sighand->siglock);
2166 sig = dequeue_signal(current, &these, &info);
2167 current->blocked = current->real_blocked;
2168 siginitset(&current->real_blocked, 0);
2169 recalc_sigpending();
2172 spin_unlock_irq(&current->sighand->siglock);
2174 if (sig) {
2175 ret = sig;
2176 if (uinfo) {
2177 if (copy_siginfo_to_user(uinfo, &info))
2178 ret = -EFAULT;
2180 } else {
2181 ret = -EAGAIN;
2182 if (timeout)
2183 ret = -EINTR;
2186 return ret;
2189 asmlinkage long
2190 sys_kill(int pid, int sig)
2192 struct siginfo info;
2194 info.si_signo = sig;
2195 info.si_errno = 0;
2196 info.si_code = SI_USER;
2197 info.si_pid = task_tgid_vnr(current);
2198 info.si_uid = current->uid;
2200 return kill_something_info(sig, &info, pid);
2203 static int do_tkill(int tgid, int pid, int sig)
2205 int error;
2206 struct siginfo info;
2207 struct task_struct *p;
2208 unsigned long flags;
2210 error = -ESRCH;
2211 info.si_signo = sig;
2212 info.si_errno = 0;
2213 info.si_code = SI_TKILL;
2214 info.si_pid = task_tgid_vnr(current);
2215 info.si_uid = current->uid;
2217 rcu_read_lock();
2218 p = find_task_by_vpid(pid);
2219 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2220 error = check_kill_permission(sig, &info, p);
2222 * The null signal is a permissions and process existence
2223 * probe. No signal is actually delivered.
2225 * If lock_task_sighand() fails we pretend the task dies
2226 * after receiving the signal. The window is tiny, and the
2227 * signal is private anyway.
2229 if (!error && sig && lock_task_sighand(p, &flags)) {
2230 error = specific_send_sig_info(sig, &info, p);
2231 unlock_task_sighand(p, &flags);
2234 rcu_read_unlock();
2236 return error;
2240 * sys_tgkill - send signal to one specific thread
2241 * @tgid: the thread group ID of the thread
2242 * @pid: the PID of the thread
2243 * @sig: signal to be sent
2245 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2246 * exists but it's not belonging to the target process anymore. This
2247 * method solves the problem of threads exiting and PIDs getting reused.
2249 asmlinkage long sys_tgkill(int tgid, int pid, int sig)
2251 /* This is only valid for single tasks */
2252 if (pid <= 0 || tgid <= 0)
2253 return -EINVAL;
2255 return do_tkill(tgid, pid, sig);
2259 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2261 asmlinkage long
2262 sys_tkill(int pid, int sig)
2264 /* This is only valid for single tasks */
2265 if (pid <= 0)
2266 return -EINVAL;
2268 return do_tkill(0, pid, sig);
2271 asmlinkage long
2272 sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo)
2274 siginfo_t info;
2276 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2277 return -EFAULT;
2279 /* Not even root can pretend to send signals from the kernel.
2280 Nor can they impersonate a kill(), which adds source info. */
2281 if (info.si_code >= 0)
2282 return -EPERM;
2283 info.si_signo = sig;
2285 /* POSIX.1b doesn't mention process groups. */
2286 return kill_proc_info(sig, &info, pid);
2289 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
2291 struct task_struct *t = current;
2292 struct k_sigaction *k;
2293 sigset_t mask;
2295 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
2296 return -EINVAL;
2298 k = &t->sighand->action[sig-1];
2300 spin_lock_irq(&current->sighand->siglock);
2301 if (oact)
2302 *oact = *k;
2304 if (act) {
2305 sigdelsetmask(&act->sa.sa_mask,
2306 sigmask(SIGKILL) | sigmask(SIGSTOP));
2307 *k = *act;
2309 * POSIX 3.3.1.3:
2310 * "Setting a signal action to SIG_IGN for a signal that is
2311 * pending shall cause the pending signal to be discarded,
2312 * whether or not it is blocked."
2314 * "Setting a signal action to SIG_DFL for a signal that is
2315 * pending and whose default action is to ignore the signal
2316 * (for example, SIGCHLD), shall cause the pending signal to
2317 * be discarded, whether or not it is blocked"
2319 if (__sig_ignored(t, sig)) {
2320 sigemptyset(&mask);
2321 sigaddset(&mask, sig);
2322 rm_from_queue_full(&mask, &t->signal->shared_pending);
2323 do {
2324 rm_from_queue_full(&mask, &t->pending);
2325 t = next_thread(t);
2326 } while (t != current);
2330 spin_unlock_irq(&current->sighand->siglock);
2331 return 0;
2334 int
2335 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
2337 stack_t oss;
2338 int error;
2340 if (uoss) {
2341 oss.ss_sp = (void __user *) current->sas_ss_sp;
2342 oss.ss_size = current->sas_ss_size;
2343 oss.ss_flags = sas_ss_flags(sp);
2346 if (uss) {
2347 void __user *ss_sp;
2348 size_t ss_size;
2349 int ss_flags;
2351 error = -EFAULT;
2352 if (!access_ok(VERIFY_READ, uss, sizeof(*uss))
2353 || __get_user(ss_sp, &uss->ss_sp)
2354 || __get_user(ss_flags, &uss->ss_flags)
2355 || __get_user(ss_size, &uss->ss_size))
2356 goto out;
2358 error = -EPERM;
2359 if (on_sig_stack(sp))
2360 goto out;
2362 error = -EINVAL;
2365 * Note - this code used to test ss_flags incorrectly
2366 * old code may have been written using ss_flags==0
2367 * to mean ss_flags==SS_ONSTACK (as this was the only
2368 * way that worked) - this fix preserves that older
2369 * mechanism
2371 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
2372 goto out;
2374 if (ss_flags == SS_DISABLE) {
2375 ss_size = 0;
2376 ss_sp = NULL;
2377 } else {
2378 error = -ENOMEM;
2379 if (ss_size < MINSIGSTKSZ)
2380 goto out;
2383 current->sas_ss_sp = (unsigned long) ss_sp;
2384 current->sas_ss_size = ss_size;
2387 if (uoss) {
2388 error = -EFAULT;
2389 if (copy_to_user(uoss, &oss, sizeof(oss)))
2390 goto out;
2393 error = 0;
2394 out:
2395 return error;
2398 #ifdef __ARCH_WANT_SYS_SIGPENDING
2400 asmlinkage long
2401 sys_sigpending(old_sigset_t __user *set)
2403 return do_sigpending(set, sizeof(*set));
2406 #endif
2408 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
2409 /* Some platforms have their own version with special arguments others
2410 support only sys_rt_sigprocmask. */
2412 asmlinkage long
2413 sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset)
2415 int error;
2416 old_sigset_t old_set, new_set;
2418 if (set) {
2419 error = -EFAULT;
2420 if (copy_from_user(&new_set, set, sizeof(*set)))
2421 goto out;
2422 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
2424 spin_lock_irq(&current->sighand->siglock);
2425 old_set = current->blocked.sig[0];
2427 error = 0;
2428 switch (how) {
2429 default:
2430 error = -EINVAL;
2431 break;
2432 case SIG_BLOCK:
2433 sigaddsetmask(&current->blocked, new_set);
2434 break;
2435 case SIG_UNBLOCK:
2436 sigdelsetmask(&current->blocked, new_set);
2437 break;
2438 case SIG_SETMASK:
2439 current->blocked.sig[0] = new_set;
2440 break;
2443 recalc_sigpending();
2444 spin_unlock_irq(&current->sighand->siglock);
2445 if (error)
2446 goto out;
2447 if (oset)
2448 goto set_old;
2449 } else if (oset) {
2450 old_set = current->blocked.sig[0];
2451 set_old:
2452 error = -EFAULT;
2453 if (copy_to_user(oset, &old_set, sizeof(*oset)))
2454 goto out;
2456 error = 0;
2457 out:
2458 return error;
2460 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
2462 #ifdef __ARCH_WANT_SYS_RT_SIGACTION
2463 asmlinkage long
2464 sys_rt_sigaction(int sig,
2465 const struct sigaction __user *act,
2466 struct sigaction __user *oact,
2467 size_t sigsetsize)
2469 struct k_sigaction new_sa, old_sa;
2470 int ret = -EINVAL;
2472 /* XXX: Don't preclude handling different sized sigset_t's. */
2473 if (sigsetsize != sizeof(sigset_t))
2474 goto out;
2476 if (act) {
2477 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
2478 return -EFAULT;
2481 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
2483 if (!ret && oact) {
2484 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
2485 return -EFAULT;
2487 out:
2488 return ret;
2490 #endif /* __ARCH_WANT_SYS_RT_SIGACTION */
2492 #ifdef __ARCH_WANT_SYS_SGETMASK
2495 * For backwards compatibility. Functionality superseded by sigprocmask.
2497 asmlinkage long
2498 sys_sgetmask(void)
2500 /* SMP safe */
2501 return current->blocked.sig[0];
2504 asmlinkage long
2505 sys_ssetmask(int newmask)
2507 int old;
2509 spin_lock_irq(&current->sighand->siglock);
2510 old = current->blocked.sig[0];
2512 siginitset(&current->blocked, newmask & ~(sigmask(SIGKILL)|
2513 sigmask(SIGSTOP)));
2514 recalc_sigpending();
2515 spin_unlock_irq(&current->sighand->siglock);
2517 return old;
2519 #endif /* __ARCH_WANT_SGETMASK */
2521 #ifdef __ARCH_WANT_SYS_SIGNAL
2523 * For backwards compatibility. Functionality superseded by sigaction.
2525 asmlinkage unsigned long
2526 sys_signal(int sig, __sighandler_t handler)
2528 struct k_sigaction new_sa, old_sa;
2529 int ret;
2531 new_sa.sa.sa_handler = handler;
2532 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
2533 sigemptyset(&new_sa.sa.sa_mask);
2535 ret = do_sigaction(sig, &new_sa, &old_sa);
2537 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
2539 #endif /* __ARCH_WANT_SYS_SIGNAL */
2541 #ifdef __ARCH_WANT_SYS_PAUSE
2543 asmlinkage long
2544 sys_pause(void)
2546 current->state = TASK_INTERRUPTIBLE;
2547 schedule();
2548 return -ERESTARTNOHAND;
2551 #endif
2553 #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
2554 asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
2556 sigset_t newset;
2558 /* XXX: Don't preclude handling different sized sigset_t's. */
2559 if (sigsetsize != sizeof(sigset_t))
2560 return -EINVAL;
2562 if (copy_from_user(&newset, unewset, sizeof(newset)))
2563 return -EFAULT;
2564 sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
2566 spin_lock_irq(&current->sighand->siglock);
2567 current->saved_sigmask = current->blocked;
2568 current->blocked = newset;
2569 recalc_sigpending();
2570 spin_unlock_irq(&current->sighand->siglock);
2572 current->state = TASK_INTERRUPTIBLE;
2573 schedule();
2574 set_restore_sigmask();
2575 return -ERESTARTNOHAND;
2577 #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
2579 __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
2581 return NULL;
2584 void __init signals_init(void)
2586 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);