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>
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/tracehook.h>
26 #include <linux/capability.h>
27 #include <linux/freezer.h>
28 #include <linux/pid_namespace.h>
29 #include <linux/nsproxy.h>
30 #include <trace/sched.h>
32 #include <asm/param.h>
33 #include <asm/uaccess.h>
34 #include <asm/unistd.h>
35 #include <asm/siginfo.h>
36 #include "audit.h" /* audit_signal_info() */
39 * SLAB caches for signal bits.
42 static struct kmem_cache
*sigqueue_cachep
;
44 DEFINE_TRACE(sched_signal_send
);
46 static void __user
*sig_handler(struct task_struct
*t
, int sig
)
48 return t
->sighand
->action
[sig
- 1].sa
.sa_handler
;
51 static int sig_handler_ignored(void __user
*handler
, int sig
)
53 /* Is it explicitly or implicitly ignored? */
54 return handler
== SIG_IGN
||
55 (handler
== SIG_DFL
&& sig_kernel_ignore(sig
));
58 static int sig_ignored(struct task_struct
*t
, int sig
)
63 * Blocked signals are never ignored, since the
64 * signal handler may change by the time it is
67 if (sigismember(&t
->blocked
, sig
) || sigismember(&t
->real_blocked
, sig
))
70 handler
= sig_handler(t
, sig
);
71 if (!sig_handler_ignored(handler
, sig
))
75 * Tracers may want to know about even ignored signals.
77 return !tracehook_consider_ignored_signal(t
, sig
, handler
);
81 * Re-calculate pending state from the set of locally pending
82 * signals, globally pending signals, and blocked signals.
84 static inline int has_pending_signals(sigset_t
*signal
, sigset_t
*blocked
)
89 switch (_NSIG_WORDS
) {
91 for (i
= _NSIG_WORDS
, ready
= 0; --i
>= 0 ;)
92 ready
|= signal
->sig
[i
] &~ blocked
->sig
[i
];
95 case 4: ready
= signal
->sig
[3] &~ blocked
->sig
[3];
96 ready
|= signal
->sig
[2] &~ blocked
->sig
[2];
97 ready
|= signal
->sig
[1] &~ blocked
->sig
[1];
98 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
101 case 2: ready
= signal
->sig
[1] &~ blocked
->sig
[1];
102 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
105 case 1: ready
= signal
->sig
[0] &~ blocked
->sig
[0];
110 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
112 static int recalc_sigpending_tsk(struct task_struct
*t
)
114 if (t
->signal
->group_stop_count
> 0 ||
115 PENDING(&t
->pending
, &t
->blocked
) ||
116 PENDING(&t
->signal
->shared_pending
, &t
->blocked
)) {
117 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
121 * We must never clear the flag in another thread, or in current
122 * when it's possible the current syscall is returning -ERESTART*.
123 * So we don't clear it here, and only callers who know they should do.
129 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
130 * This is superfluous when called on current, the wakeup is a harmless no-op.
132 void recalc_sigpending_and_wake(struct task_struct
*t
)
134 if (recalc_sigpending_tsk(t
))
135 signal_wake_up(t
, 0);
138 void recalc_sigpending(void)
140 if (unlikely(tracehook_force_sigpending()))
141 set_thread_flag(TIF_SIGPENDING
);
142 else if (!recalc_sigpending_tsk(current
) && !freezing(current
))
143 clear_thread_flag(TIF_SIGPENDING
);
147 /* Given the mask, find the first available signal that should be serviced. */
149 int next_signal(struct sigpending
*pending
, sigset_t
*mask
)
151 unsigned long i
, *s
, *m
, x
;
154 s
= pending
->signal
.sig
;
156 switch (_NSIG_WORDS
) {
158 for (i
= 0; i
< _NSIG_WORDS
; ++i
, ++s
, ++m
)
159 if ((x
= *s
&~ *m
) != 0) {
160 sig
= ffz(~x
) + i
*_NSIG_BPW
+ 1;
165 case 2: if ((x
= s
[0] &~ m
[0]) != 0)
167 else if ((x
= s
[1] &~ m
[1]) != 0)
174 case 1: if ((x
= *s
&~ *m
) != 0)
183 * allocate a new signal queue record
184 * - this may be called without locks if and only if t == current, otherwise an
185 * appopriate lock must be held to stop the target task from exiting
187 static struct sigqueue
*__sigqueue_alloc(struct task_struct
*t
, gfp_t flags
,
190 struct sigqueue
*q
= NULL
;
191 struct user_struct
*user
;
194 * We won't get problems with the target's UID changing under us
195 * because changing it requires RCU be used, and if t != current, the
196 * caller must be holding the RCU readlock (by way of a spinlock) and
197 * we use RCU protection here
199 user
= get_uid(__task_cred(t
)->user
);
200 atomic_inc(&user
->sigpending
);
201 if (override_rlimit
||
202 atomic_read(&user
->sigpending
) <=
203 t
->signal
->rlim
[RLIMIT_SIGPENDING
].rlim_cur
)
204 q
= kmem_cache_alloc(sigqueue_cachep
, flags
);
205 if (unlikely(q
== NULL
)) {
206 atomic_dec(&user
->sigpending
);
209 INIT_LIST_HEAD(&q
->list
);
217 static void __sigqueue_free(struct sigqueue
*q
)
219 if (q
->flags
& SIGQUEUE_PREALLOC
)
221 atomic_dec(&q
->user
->sigpending
);
223 kmem_cache_free(sigqueue_cachep
, q
);
226 void flush_sigqueue(struct sigpending
*queue
)
230 sigemptyset(&queue
->signal
);
231 while (!list_empty(&queue
->list
)) {
232 q
= list_entry(queue
->list
.next
, struct sigqueue
, list
);
233 list_del_init(&q
->list
);
239 * Flush all pending signals for a task.
241 void __flush_signals(struct task_struct
*t
)
243 clear_tsk_thread_flag(t
, TIF_SIGPENDING
);
244 flush_sigqueue(&t
->pending
);
245 flush_sigqueue(&t
->signal
->shared_pending
);
248 void flush_signals(struct task_struct
*t
)
252 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
254 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
257 static void __flush_itimer_signals(struct sigpending
*pending
)
259 sigset_t signal
, retain
;
260 struct sigqueue
*q
, *n
;
262 signal
= pending
->signal
;
263 sigemptyset(&retain
);
265 list_for_each_entry_safe(q
, n
, &pending
->list
, list
) {
266 int sig
= q
->info
.si_signo
;
268 if (likely(q
->info
.si_code
!= SI_TIMER
)) {
269 sigaddset(&retain
, sig
);
271 sigdelset(&signal
, sig
);
272 list_del_init(&q
->list
);
277 sigorsets(&pending
->signal
, &signal
, &retain
);
280 void flush_itimer_signals(void)
282 struct task_struct
*tsk
= current
;
285 spin_lock_irqsave(&tsk
->sighand
->siglock
, flags
);
286 __flush_itimer_signals(&tsk
->pending
);
287 __flush_itimer_signals(&tsk
->signal
->shared_pending
);
288 spin_unlock_irqrestore(&tsk
->sighand
->siglock
, flags
);
291 void ignore_signals(struct task_struct
*t
)
295 for (i
= 0; i
< _NSIG
; ++i
)
296 t
->sighand
->action
[i
].sa
.sa_handler
= SIG_IGN
;
302 * Flush all handlers for a task.
306 flush_signal_handlers(struct task_struct
*t
, int force_default
)
309 struct k_sigaction
*ka
= &t
->sighand
->action
[0];
310 for (i
= _NSIG
; i
!= 0 ; i
--) {
311 if (force_default
|| ka
->sa
.sa_handler
!= SIG_IGN
)
312 ka
->sa
.sa_handler
= SIG_DFL
;
314 sigemptyset(&ka
->sa
.sa_mask
);
319 int unhandled_signal(struct task_struct
*tsk
, int sig
)
321 void __user
*handler
= tsk
->sighand
->action
[sig
-1].sa
.sa_handler
;
322 if (is_global_init(tsk
))
324 if (handler
!= SIG_IGN
&& handler
!= SIG_DFL
)
326 return !tracehook_consider_fatal_signal(tsk
, sig
, handler
);
330 /* Notify the system that a driver wants to block all signals for this
331 * process, and wants to be notified if any signals at all were to be
332 * sent/acted upon. If the notifier routine returns non-zero, then the
333 * signal will be acted upon after all. If the notifier routine returns 0,
334 * then then signal will be blocked. Only one block per process is
335 * allowed. priv is a pointer to private data that the notifier routine
336 * can use to determine if the signal should be blocked or not. */
339 block_all_signals(int (*notifier
)(void *priv
), void *priv
, sigset_t
*mask
)
343 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
344 current
->notifier_mask
= mask
;
345 current
->notifier_data
= priv
;
346 current
->notifier
= notifier
;
347 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
350 /* Notify the system that blocking has ended. */
353 unblock_all_signals(void)
357 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
358 current
->notifier
= NULL
;
359 current
->notifier_data
= NULL
;
361 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
364 static void collect_signal(int sig
, struct sigpending
*list
, siginfo_t
*info
)
366 struct sigqueue
*q
, *first
= NULL
;
369 * Collect the siginfo appropriate to this signal. Check if
370 * there is another siginfo for the same signal.
372 list_for_each_entry(q
, &list
->list
, list
) {
373 if (q
->info
.si_signo
== sig
) {
380 sigdelset(&list
->signal
, sig
);
384 list_del_init(&first
->list
);
385 copy_siginfo(info
, &first
->info
);
386 __sigqueue_free(first
);
388 /* Ok, it wasn't in the queue. This must be
389 a fast-pathed signal or we must have been
390 out of queue space. So zero out the info.
392 info
->si_signo
= sig
;
400 static int __dequeue_signal(struct sigpending
*pending
, sigset_t
*mask
,
403 int sig
= next_signal(pending
, mask
);
406 if (current
->notifier
) {
407 if (sigismember(current
->notifier_mask
, sig
)) {
408 if (!(current
->notifier
)(current
->notifier_data
)) {
409 clear_thread_flag(TIF_SIGPENDING
);
415 collect_signal(sig
, pending
, info
);
422 * Dequeue a signal and return the element to the caller, which is
423 * expected to free it.
425 * All callers have to hold the siglock.
427 int dequeue_signal(struct task_struct
*tsk
, sigset_t
*mask
, siginfo_t
*info
)
431 /* We only dequeue private signals from ourselves, we don't let
432 * signalfd steal them
434 signr
= __dequeue_signal(&tsk
->pending
, mask
, info
);
436 signr
= __dequeue_signal(&tsk
->signal
->shared_pending
,
441 * itimers are process shared and we restart periodic
442 * itimers in the signal delivery path to prevent DoS
443 * attacks in the high resolution timer case. This is
444 * compliant with the old way of self restarting
445 * itimers, as the SIGALRM is a legacy signal and only
446 * queued once. Changing the restart behaviour to
447 * restart the timer in the signal dequeue path is
448 * reducing the timer noise on heavy loaded !highres
451 if (unlikely(signr
== SIGALRM
)) {
452 struct hrtimer
*tmr
= &tsk
->signal
->real_timer
;
454 if (!hrtimer_is_queued(tmr
) &&
455 tsk
->signal
->it_real_incr
.tv64
!= 0) {
456 hrtimer_forward(tmr
, tmr
->base
->get_time(),
457 tsk
->signal
->it_real_incr
);
458 hrtimer_restart(tmr
);
467 if (unlikely(sig_kernel_stop(signr
))) {
469 * Set a marker that we have dequeued a stop signal. Our
470 * caller might release the siglock and then the pending
471 * stop signal it is about to process is no longer in the
472 * pending bitmasks, but must still be cleared by a SIGCONT
473 * (and overruled by a SIGKILL). So those cases clear this
474 * shared flag after we've set it. Note that this flag may
475 * remain set after the signal we return is ignored or
476 * handled. That doesn't matter because its only purpose
477 * is to alert stop-signal processing code when another
478 * processor has come along and cleared the flag.
480 tsk
->signal
->flags
|= SIGNAL_STOP_DEQUEUED
;
482 if ((info
->si_code
& __SI_MASK
) == __SI_TIMER
&& info
->si_sys_private
) {
484 * Release the siglock to ensure proper locking order
485 * of timer locks outside of siglocks. Note, we leave
486 * irqs disabled here, since the posix-timers code is
487 * about to disable them again anyway.
489 spin_unlock(&tsk
->sighand
->siglock
);
490 do_schedule_next_timer(info
);
491 spin_lock(&tsk
->sighand
->siglock
);
497 * Tell a process that it has a new active signal..
499 * NOTE! we rely on the previous spin_lock to
500 * lock interrupts for us! We can only be called with
501 * "siglock" held, and the local interrupt must
502 * have been disabled when that got acquired!
504 * No need to set need_resched since signal event passing
505 * goes through ->blocked
507 void signal_wake_up(struct task_struct
*t
, int resume
)
511 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
514 * For SIGKILL, we want to wake it up in the stopped/traced/killable
515 * case. We don't check t->state here because there is a race with it
516 * executing another processor and just now entering stopped state.
517 * By using wake_up_state, we ensure the process will wake up and
518 * handle its death signal.
520 mask
= TASK_INTERRUPTIBLE
;
522 mask
|= TASK_WAKEKILL
;
523 if (!wake_up_state(t
, mask
))
528 * Remove signals in mask from the pending set and queue.
529 * Returns 1 if any signals were found.
531 * All callers must be holding the siglock.
533 * This version takes a sigset mask and looks at all signals,
534 * not just those in the first mask word.
536 static int rm_from_queue_full(sigset_t
*mask
, struct sigpending
*s
)
538 struct sigqueue
*q
, *n
;
541 sigandsets(&m
, mask
, &s
->signal
);
542 if (sigisemptyset(&m
))
545 signandsets(&s
->signal
, &s
->signal
, mask
);
546 list_for_each_entry_safe(q
, n
, &s
->list
, list
) {
547 if (sigismember(mask
, q
->info
.si_signo
)) {
548 list_del_init(&q
->list
);
555 * Remove signals in mask from the pending set and queue.
556 * Returns 1 if any signals were found.
558 * All callers must be holding the siglock.
560 static int rm_from_queue(unsigned long mask
, struct sigpending
*s
)
562 struct sigqueue
*q
, *n
;
564 if (!sigtestsetmask(&s
->signal
, mask
))
567 sigdelsetmask(&s
->signal
, mask
);
568 list_for_each_entry_safe(q
, n
, &s
->list
, list
) {
569 if (q
->info
.si_signo
< SIGRTMIN
&&
570 (mask
& sigmask(q
->info
.si_signo
))) {
571 list_del_init(&q
->list
);
579 * Bad permissions for sending the signal
580 * - the caller must hold at least the RCU read lock
582 static int check_kill_permission(int sig
, struct siginfo
*info
,
583 struct task_struct
*t
)
585 const struct cred
*cred
= current_cred(), *tcred
;
589 if (!valid_signal(sig
))
592 if (info
!= SEND_SIG_NOINFO
&& (is_si_special(info
) || SI_FROMKERNEL(info
)))
595 error
= audit_signal_info(sig
, t
); /* Let audit system see the signal */
599 tcred
= __task_cred(t
);
600 if ((cred
->euid
^ tcred
->suid
) &&
601 (cred
->euid
^ tcred
->uid
) &&
602 (cred
->uid
^ tcred
->suid
) &&
603 (cred
->uid
^ tcred
->uid
) &&
604 !capable(CAP_KILL
)) {
607 sid
= task_session(t
);
609 * We don't return the error if sid == NULL. The
610 * task was unhashed, the caller must notice this.
612 if (!sid
|| sid
== task_session(current
))
619 return security_task_kill(t
, info
, sig
, 0);
623 * Handle magic process-wide effects of stop/continue signals. Unlike
624 * the signal actions, these happen immediately at signal-generation
625 * time regardless of blocking, ignoring, or handling. This does the
626 * actual continuing for SIGCONT, but not the actual stopping for stop
627 * signals. The process stop is done as a signal action for SIG_DFL.
629 * Returns true if the signal should be actually delivered, otherwise
630 * it should be dropped.
632 static int prepare_signal(int sig
, struct task_struct
*p
)
634 struct signal_struct
*signal
= p
->signal
;
635 struct task_struct
*t
;
637 if (unlikely(signal
->flags
& SIGNAL_GROUP_EXIT
)) {
639 * The process is in the middle of dying, nothing to do.
641 } else if (sig_kernel_stop(sig
)) {
643 * This is a stop signal. Remove SIGCONT from all queues.
645 rm_from_queue(sigmask(SIGCONT
), &signal
->shared_pending
);
648 rm_from_queue(sigmask(SIGCONT
), &t
->pending
);
649 } while_each_thread(p
, t
);
650 } else if (sig
== SIGCONT
) {
653 * Remove all stop signals from all queues,
654 * and wake all threads.
656 rm_from_queue(SIG_KERNEL_STOP_MASK
, &signal
->shared_pending
);
660 rm_from_queue(SIG_KERNEL_STOP_MASK
, &t
->pending
);
662 * If there is a handler for SIGCONT, we must make
663 * sure that no thread returns to user mode before
664 * we post the signal, in case it was the only
665 * thread eligible to run the signal handler--then
666 * it must not do anything between resuming and
667 * running the handler. With the TIF_SIGPENDING
668 * flag set, the thread will pause and acquire the
669 * siglock that we hold now and until we've queued
670 * the pending signal.
672 * Wake up the stopped thread _after_ setting
675 state
= __TASK_STOPPED
;
676 if (sig_user_defined(t
, SIGCONT
) && !sigismember(&t
->blocked
, SIGCONT
)) {
677 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
678 state
|= TASK_INTERRUPTIBLE
;
680 wake_up_state(t
, state
);
681 } while_each_thread(p
, t
);
684 * Notify the parent with CLD_CONTINUED if we were stopped.
686 * If we were in the middle of a group stop, we pretend it
687 * was already finished, and then continued. Since SIGCHLD
688 * doesn't queue we report only CLD_STOPPED, as if the next
689 * CLD_CONTINUED was dropped.
692 if (signal
->flags
& SIGNAL_STOP_STOPPED
)
693 why
|= SIGNAL_CLD_CONTINUED
;
694 else if (signal
->group_stop_count
)
695 why
|= SIGNAL_CLD_STOPPED
;
699 * The first thread which returns from finish_stop()
700 * will take ->siglock, notice SIGNAL_CLD_MASK, and
701 * notify its parent. See get_signal_to_deliver().
703 signal
->flags
= why
| SIGNAL_STOP_CONTINUED
;
704 signal
->group_stop_count
= 0;
705 signal
->group_exit_code
= 0;
708 * We are not stopped, but there could be a stop
709 * signal in the middle of being processed after
710 * being removed from the queue. Clear that too.
712 signal
->flags
&= ~SIGNAL_STOP_DEQUEUED
;
716 return !sig_ignored(p
, sig
);
720 * Test if P wants to take SIG. After we've checked all threads with this,
721 * it's equivalent to finding no threads not blocking SIG. Any threads not
722 * blocking SIG were ruled out because they are not running and already
723 * have pending signals. Such threads will dequeue from the shared queue
724 * as soon as they're available, so putting the signal on the shared queue
725 * will be equivalent to sending it to one such thread.
727 static inline int wants_signal(int sig
, struct task_struct
*p
)
729 if (sigismember(&p
->blocked
, sig
))
731 if (p
->flags
& PF_EXITING
)
735 if (task_is_stopped_or_traced(p
))
737 return task_curr(p
) || !signal_pending(p
);
740 static void complete_signal(int sig
, struct task_struct
*p
, int group
)
742 struct signal_struct
*signal
= p
->signal
;
743 struct task_struct
*t
;
746 * Now find a thread we can wake up to take the signal off the queue.
748 * If the main thread wants the signal, it gets first crack.
749 * Probably the least surprising to the average bear.
751 if (wants_signal(sig
, p
))
753 else if (!group
|| thread_group_empty(p
))
755 * There is just one thread and it does not need to be woken.
756 * It will dequeue unblocked signals before it runs again.
761 * Otherwise try to find a suitable thread.
763 t
= signal
->curr_target
;
764 while (!wants_signal(sig
, t
)) {
766 if (t
== signal
->curr_target
)
768 * No thread needs to be woken.
769 * Any eligible threads will see
770 * the signal in the queue soon.
774 signal
->curr_target
= t
;
778 * Found a killable thread. If the signal will be fatal,
779 * then start taking the whole group down immediately.
781 if (sig_fatal(p
, sig
) &&
782 !(signal
->flags
& (SIGNAL_UNKILLABLE
| SIGNAL_GROUP_EXIT
)) &&
783 !sigismember(&t
->real_blocked
, sig
) &&
785 !tracehook_consider_fatal_signal(t
, sig
, SIG_DFL
))) {
787 * This signal will be fatal to the whole group.
789 if (!sig_kernel_coredump(sig
)) {
791 * Start a group exit and wake everybody up.
792 * This way we don't have other threads
793 * running and doing things after a slower
794 * thread has the fatal signal pending.
796 signal
->flags
= SIGNAL_GROUP_EXIT
;
797 signal
->group_exit_code
= sig
;
798 signal
->group_stop_count
= 0;
801 sigaddset(&t
->pending
.signal
, SIGKILL
);
802 signal_wake_up(t
, 1);
803 } while_each_thread(p
, t
);
809 * The signal is already in the shared-pending queue.
810 * Tell the chosen thread to wake up and dequeue it.
812 signal_wake_up(t
, sig
== SIGKILL
);
816 static inline int legacy_queue(struct sigpending
*signals
, int sig
)
818 return (sig
< SIGRTMIN
) && sigismember(&signals
->signal
, sig
);
821 static int send_signal(int sig
, struct siginfo
*info
, struct task_struct
*t
,
824 struct sigpending
*pending
;
827 trace_sched_signal_send(sig
, t
);
829 assert_spin_locked(&t
->sighand
->siglock
);
830 if (!prepare_signal(sig
, t
))
833 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
835 * Short-circuit ignored signals and support queuing
836 * exactly one non-rt signal, so that we can get more
837 * detailed information about the cause of the signal.
839 if (legacy_queue(pending
, sig
))
842 * fast-pathed signals for kernel-internal things like SIGSTOP
845 if (info
== SEND_SIG_FORCED
)
848 /* Real-time signals must be queued if sent by sigqueue, or
849 some other real-time mechanism. It is implementation
850 defined whether kill() does so. We attempt to do so, on
851 the principle of least surprise, but since kill is not
852 allowed to fail with EAGAIN when low on memory we just
853 make sure at least one signal gets delivered and don't
854 pass on the info struct. */
856 q
= __sigqueue_alloc(t
, GFP_ATOMIC
, (sig
< SIGRTMIN
&&
857 (is_si_special(info
) ||
858 info
->si_code
>= 0)));
860 list_add_tail(&q
->list
, &pending
->list
);
861 switch ((unsigned long) info
) {
862 case (unsigned long) SEND_SIG_NOINFO
:
863 q
->info
.si_signo
= sig
;
864 q
->info
.si_errno
= 0;
865 q
->info
.si_code
= SI_USER
;
866 q
->info
.si_pid
= task_tgid_nr_ns(current
,
867 task_active_pid_ns(t
));
868 q
->info
.si_uid
= current_uid();
870 case (unsigned long) SEND_SIG_PRIV
:
871 q
->info
.si_signo
= sig
;
872 q
->info
.si_errno
= 0;
873 q
->info
.si_code
= SI_KERNEL
;
878 copy_siginfo(&q
->info
, info
);
881 } else if (!is_si_special(info
)) {
882 if (sig
>= SIGRTMIN
&& info
->si_code
!= SI_USER
)
884 * Queue overflow, abort. We may abort if the signal was rt
885 * and sent by user using something other than kill().
891 signalfd_notify(t
, sig
);
892 sigaddset(&pending
->signal
, sig
);
893 complete_signal(sig
, t
, group
);
897 int print_fatal_signals
;
899 static void print_fatal_signal(struct pt_regs
*regs
, int signr
)
901 printk("%s/%d: potentially unexpected fatal signal %d.\n",
902 current
->comm
, task_pid_nr(current
), signr
);
904 #if defined(__i386__) && !defined(__arch_um__)
905 printk("code at %08lx: ", regs
->ip
);
908 for (i
= 0; i
< 16; i
++) {
911 __get_user(insn
, (unsigned char *)(regs
->ip
+ i
));
912 printk("%02x ", insn
);
922 static int __init
setup_print_fatal_signals(char *str
)
924 get_option (&str
, &print_fatal_signals
);
929 __setup("print-fatal-signals=", setup_print_fatal_signals
);
932 __group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
934 return send_signal(sig
, info
, p
, 1);
938 specific_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
940 return send_signal(sig
, info
, t
, 0);
944 * Force a signal that the process can't ignore: if necessary
945 * we unblock the signal and change any SIG_IGN to SIG_DFL.
947 * Note: If we unblock the signal, we always reset it to SIG_DFL,
948 * since we do not want to have a signal handler that was blocked
949 * be invoked when user space had explicitly blocked it.
951 * We don't want to have recursive SIGSEGV's etc, for example,
952 * that is why we also clear SIGNAL_UNKILLABLE.
955 force_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
957 unsigned long int flags
;
958 int ret
, blocked
, ignored
;
959 struct k_sigaction
*action
;
961 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
962 action
= &t
->sighand
->action
[sig
-1];
963 ignored
= action
->sa
.sa_handler
== SIG_IGN
;
964 blocked
= sigismember(&t
->blocked
, sig
);
965 if (blocked
|| ignored
) {
966 action
->sa
.sa_handler
= SIG_DFL
;
968 sigdelset(&t
->blocked
, sig
);
969 recalc_sigpending_and_wake(t
);
972 if (action
->sa
.sa_handler
== SIG_DFL
)
973 t
->signal
->flags
&= ~SIGNAL_UNKILLABLE
;
974 ret
= specific_send_sig_info(sig
, info
, t
);
975 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
981 force_sig_specific(int sig
, struct task_struct
*t
)
983 force_sig_info(sig
, SEND_SIG_FORCED
, t
);
987 * Nuke all other threads in the group.
989 void zap_other_threads(struct task_struct
*p
)
991 struct task_struct
*t
;
993 p
->signal
->group_stop_count
= 0;
995 for (t
= next_thread(p
); t
!= p
; t
= next_thread(t
)) {
997 * Don't bother with already dead threads
1002 /* SIGKILL will be handled before any pending SIGSTOP */
1003 sigaddset(&t
->pending
.signal
, SIGKILL
);
1004 signal_wake_up(t
, 1);
1008 int __fatal_signal_pending(struct task_struct
*tsk
)
1010 return sigismember(&tsk
->pending
.signal
, SIGKILL
);
1012 EXPORT_SYMBOL(__fatal_signal_pending
);
1014 struct sighand_struct
*lock_task_sighand(struct task_struct
*tsk
, unsigned long *flags
)
1016 struct sighand_struct
*sighand
;
1020 sighand
= rcu_dereference(tsk
->sighand
);
1021 if (unlikely(sighand
== NULL
))
1024 spin_lock_irqsave(&sighand
->siglock
, *flags
);
1025 if (likely(sighand
== tsk
->sighand
))
1027 spin_unlock_irqrestore(&sighand
->siglock
, *flags
);
1035 * send signal info to all the members of a group
1036 * - the caller must hold the RCU read lock at least
1038 int group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1040 unsigned long flags
;
1043 ret
= check_kill_permission(sig
, info
, p
);
1047 if (lock_task_sighand(p
, &flags
)) {
1048 ret
= __group_send_sig_info(sig
, info
, p
);
1049 unlock_task_sighand(p
, &flags
);
1057 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1058 * control characters do (^C, ^Z etc)
1059 * - the caller must hold at least a readlock on tasklist_lock
1061 int __kill_pgrp_info(int sig
, struct siginfo
*info
, struct pid
*pgrp
)
1063 struct task_struct
*p
= NULL
;
1064 int retval
, success
;
1068 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
1069 int err
= group_send_sig_info(sig
, info
, p
);
1072 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
1073 return success
? 0 : retval
;
1076 int kill_pid_info(int sig
, struct siginfo
*info
, struct pid
*pid
)
1079 struct task_struct
*p
;
1083 p
= pid_task(pid
, PIDTYPE_PID
);
1085 error
= group_send_sig_info(sig
, info
, p
);
1086 if (unlikely(error
== -ESRCH
))
1088 * The task was unhashed in between, try again.
1089 * If it is dead, pid_task() will return NULL,
1090 * if we race with de_thread() it will find the
1101 kill_proc_info(int sig
, struct siginfo
*info
, pid_t pid
)
1105 error
= kill_pid_info(sig
, info
, find_vpid(pid
));
1110 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1111 int kill_pid_info_as_uid(int sig
, struct siginfo
*info
, struct pid
*pid
,
1112 uid_t uid
, uid_t euid
, u32 secid
)
1115 struct task_struct
*p
;
1116 const struct cred
*pcred
;
1118 if (!valid_signal(sig
))
1121 read_lock(&tasklist_lock
);
1122 p
= pid_task(pid
, PIDTYPE_PID
);
1127 pcred
= __task_cred(p
);
1128 if ((info
== SEND_SIG_NOINFO
||
1129 (!is_si_special(info
) && SI_FROMUSER(info
))) &&
1130 euid
!= pcred
->suid
&& euid
!= pcred
->uid
&&
1131 uid
!= pcred
->suid
&& uid
!= pcred
->uid
) {
1135 ret
= security_task_kill(p
, info
, sig
, secid
);
1138 if (sig
&& p
->sighand
) {
1139 unsigned long flags
;
1140 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
1141 ret
= __group_send_sig_info(sig
, info
, p
);
1142 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
1145 read_unlock(&tasklist_lock
);
1148 EXPORT_SYMBOL_GPL(kill_pid_info_as_uid
);
1151 * kill_something_info() interprets pid in interesting ways just like kill(2).
1153 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1154 * is probably wrong. Should make it like BSD or SYSV.
1157 static int kill_something_info(int sig
, struct siginfo
*info
, pid_t pid
)
1163 ret
= kill_pid_info(sig
, info
, find_vpid(pid
));
1168 read_lock(&tasklist_lock
);
1170 ret
= __kill_pgrp_info(sig
, info
,
1171 pid
? find_vpid(-pid
) : task_pgrp(current
));
1173 int retval
= 0, count
= 0;
1174 struct task_struct
* p
;
1176 for_each_process(p
) {
1177 if (task_pid_vnr(p
) > 1 &&
1178 !same_thread_group(p
, current
)) {
1179 int err
= group_send_sig_info(sig
, info
, p
);
1185 ret
= count
? retval
: -ESRCH
;
1187 read_unlock(&tasklist_lock
);
1193 * These are for backward compatibility with the rest of the kernel source.
1197 * The caller must ensure the task can't exit.
1200 send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1203 unsigned long flags
;
1206 * Make sure legacy kernel users don't send in bad values
1207 * (normal paths check this in check_kill_permission).
1209 if (!valid_signal(sig
))
1212 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
1213 ret
= specific_send_sig_info(sig
, info
, p
);
1214 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
1218 #define __si_special(priv) \
1219 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1222 send_sig(int sig
, struct task_struct
*p
, int priv
)
1224 return send_sig_info(sig
, __si_special(priv
), p
);
1228 force_sig(int sig
, struct task_struct
*p
)
1230 force_sig_info(sig
, SEND_SIG_PRIV
, p
);
1234 * When things go south during signal handling, we
1235 * will force a SIGSEGV. And if the signal that caused
1236 * the problem was already a SIGSEGV, we'll want to
1237 * make sure we don't even try to deliver the signal..
1240 force_sigsegv(int sig
, struct task_struct
*p
)
1242 if (sig
== SIGSEGV
) {
1243 unsigned long flags
;
1244 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
1245 p
->sighand
->action
[sig
- 1].sa
.sa_handler
= SIG_DFL
;
1246 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
1248 force_sig(SIGSEGV
, p
);
1252 int kill_pgrp(struct pid
*pid
, int sig
, int priv
)
1256 read_lock(&tasklist_lock
);
1257 ret
= __kill_pgrp_info(sig
, __si_special(priv
), pid
);
1258 read_unlock(&tasklist_lock
);
1262 EXPORT_SYMBOL(kill_pgrp
);
1264 int kill_pid(struct pid
*pid
, int sig
, int priv
)
1266 return kill_pid_info(sig
, __si_special(priv
), pid
);
1268 EXPORT_SYMBOL(kill_pid
);
1271 * These functions support sending signals using preallocated sigqueue
1272 * structures. This is needed "because realtime applications cannot
1273 * afford to lose notifications of asynchronous events, like timer
1274 * expirations or I/O completions". In the case of Posix Timers
1275 * we allocate the sigqueue structure from the timer_create. If this
1276 * allocation fails we are able to report the failure to the application
1277 * with an EAGAIN error.
1280 struct sigqueue
*sigqueue_alloc(void)
1284 if ((q
= __sigqueue_alloc(current
, GFP_KERNEL
, 0)))
1285 q
->flags
|= SIGQUEUE_PREALLOC
;
1289 void sigqueue_free(struct sigqueue
*q
)
1291 unsigned long flags
;
1292 spinlock_t
*lock
= ¤t
->sighand
->siglock
;
1294 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1296 * We must hold ->siglock while testing q->list
1297 * to serialize with collect_signal() or with
1298 * __exit_signal()->flush_sigqueue().
1300 spin_lock_irqsave(lock
, flags
);
1301 q
->flags
&= ~SIGQUEUE_PREALLOC
;
1303 * If it is queued it will be freed when dequeued,
1304 * like the "regular" sigqueue.
1306 if (!list_empty(&q
->list
))
1308 spin_unlock_irqrestore(lock
, flags
);
1314 int send_sigqueue(struct sigqueue
*q
, struct task_struct
*t
, int group
)
1316 int sig
= q
->info
.si_signo
;
1317 struct sigpending
*pending
;
1318 unsigned long flags
;
1321 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1324 if (!likely(lock_task_sighand(t
, &flags
)))
1327 ret
= 1; /* the signal is ignored */
1328 if (!prepare_signal(sig
, t
))
1332 if (unlikely(!list_empty(&q
->list
))) {
1334 * If an SI_TIMER entry is already queue just increment
1335 * the overrun count.
1337 BUG_ON(q
->info
.si_code
!= SI_TIMER
);
1338 q
->info
.si_overrun
++;
1341 q
->info
.si_overrun
= 0;
1343 signalfd_notify(t
, sig
);
1344 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
1345 list_add_tail(&q
->list
, &pending
->list
);
1346 sigaddset(&pending
->signal
, sig
);
1347 complete_signal(sig
, t
, group
);
1349 unlock_task_sighand(t
, &flags
);
1355 * Wake up any threads in the parent blocked in wait* syscalls.
1357 static inline void __wake_up_parent(struct task_struct
*p
,
1358 struct task_struct
*parent
)
1360 wake_up_interruptible_sync(&parent
->signal
->wait_chldexit
);
1364 * Let a parent know about the death of a child.
1365 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1367 * Returns -1 if our parent ignored us and so we've switched to
1368 * self-reaping, or else @sig.
1370 int do_notify_parent(struct task_struct
*tsk
, int sig
)
1372 struct siginfo info
;
1373 unsigned long flags
;
1374 struct sighand_struct
*psig
;
1379 /* do_notify_parent_cldstop should have been called instead. */
1380 BUG_ON(task_is_stopped_or_traced(tsk
));
1382 BUG_ON(!tsk
->ptrace
&&
1383 (tsk
->group_leader
!= tsk
|| !thread_group_empty(tsk
)));
1385 info
.si_signo
= sig
;
1388 * we are under tasklist_lock here so our parent is tied to
1389 * us and cannot exit and release its namespace.
1391 * the only it can is to switch its nsproxy with sys_unshare,
1392 * bu uncharing pid namespaces is not allowed, so we'll always
1393 * see relevant namespace
1395 * write_lock() currently calls preempt_disable() which is the
1396 * same as rcu_read_lock(), but according to Oleg, this is not
1397 * correct to rely on this
1400 info
.si_pid
= task_pid_nr_ns(tsk
, tsk
->parent
->nsproxy
->pid_ns
);
1401 info
.si_uid
= __task_cred(tsk
)->uid
;
1404 info
.si_utime
= cputime_to_clock_t(cputime_add(tsk
->utime
,
1405 tsk
->signal
->utime
));
1406 info
.si_stime
= cputime_to_clock_t(cputime_add(tsk
->stime
,
1407 tsk
->signal
->stime
));
1409 info
.si_status
= tsk
->exit_code
& 0x7f;
1410 if (tsk
->exit_code
& 0x80)
1411 info
.si_code
= CLD_DUMPED
;
1412 else if (tsk
->exit_code
& 0x7f)
1413 info
.si_code
= CLD_KILLED
;
1415 info
.si_code
= CLD_EXITED
;
1416 info
.si_status
= tsk
->exit_code
>> 8;
1419 psig
= tsk
->parent
->sighand
;
1420 spin_lock_irqsave(&psig
->siglock
, flags
);
1421 if (!tsk
->ptrace
&& sig
== SIGCHLD
&&
1422 (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
||
1423 (psig
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDWAIT
))) {
1425 * We are exiting and our parent doesn't care. POSIX.1
1426 * defines special semantics for setting SIGCHLD to SIG_IGN
1427 * or setting the SA_NOCLDWAIT flag: we should be reaped
1428 * automatically and not left for our parent's wait4 call.
1429 * Rather than having the parent do it as a magic kind of
1430 * signal handler, we just set this to tell do_exit that we
1431 * can be cleaned up without becoming a zombie. Note that
1432 * we still call __wake_up_parent in this case, because a
1433 * blocked sys_wait4 might now return -ECHILD.
1435 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1436 * is implementation-defined: we do (if you don't want
1437 * it, just use SIG_IGN instead).
1439 ret
= tsk
->exit_signal
= -1;
1440 if (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
)
1443 if (valid_signal(sig
) && sig
> 0)
1444 __group_send_sig_info(sig
, &info
, tsk
->parent
);
1445 __wake_up_parent(tsk
, tsk
->parent
);
1446 spin_unlock_irqrestore(&psig
->siglock
, flags
);
1451 static void do_notify_parent_cldstop(struct task_struct
*tsk
, int why
)
1453 struct siginfo info
;
1454 unsigned long flags
;
1455 struct task_struct
*parent
;
1456 struct sighand_struct
*sighand
;
1458 if (tsk
->ptrace
& PT_PTRACED
)
1459 parent
= tsk
->parent
;
1461 tsk
= tsk
->group_leader
;
1462 parent
= tsk
->real_parent
;
1465 info
.si_signo
= SIGCHLD
;
1468 * see comment in do_notify_parent() abot the following 3 lines
1471 info
.si_pid
= task_pid_nr_ns(tsk
, tsk
->parent
->nsproxy
->pid_ns
);
1472 info
.si_uid
= __task_cred(tsk
)->uid
;
1475 info
.si_utime
= cputime_to_clock_t(tsk
->utime
);
1476 info
.si_stime
= cputime_to_clock_t(tsk
->stime
);
1481 info
.si_status
= SIGCONT
;
1484 info
.si_status
= tsk
->signal
->group_exit_code
& 0x7f;
1487 info
.si_status
= tsk
->exit_code
& 0x7f;
1493 sighand
= parent
->sighand
;
1494 spin_lock_irqsave(&sighand
->siglock
, flags
);
1495 if (sighand
->action
[SIGCHLD
-1].sa
.sa_handler
!= SIG_IGN
&&
1496 !(sighand
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDSTOP
))
1497 __group_send_sig_info(SIGCHLD
, &info
, parent
);
1499 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1501 __wake_up_parent(tsk
, parent
);
1502 spin_unlock_irqrestore(&sighand
->siglock
, flags
);
1505 static inline int may_ptrace_stop(void)
1507 if (!likely(current
->ptrace
& PT_PTRACED
))
1510 * Are we in the middle of do_coredump?
1511 * If so and our tracer is also part of the coredump stopping
1512 * is a deadlock situation, and pointless because our tracer
1513 * is dead so don't allow us to stop.
1514 * If SIGKILL was already sent before the caller unlocked
1515 * ->siglock we must see ->core_state != NULL. Otherwise it
1516 * is safe to enter schedule().
1518 if (unlikely(current
->mm
->core_state
) &&
1519 unlikely(current
->mm
== current
->parent
->mm
))
1526 * Return nonzero if there is a SIGKILL that should be waking us up.
1527 * Called with the siglock held.
1529 static int sigkill_pending(struct task_struct
*tsk
)
1531 return sigismember(&tsk
->pending
.signal
, SIGKILL
) ||
1532 sigismember(&tsk
->signal
->shared_pending
.signal
, SIGKILL
);
1536 * This must be called with current->sighand->siglock held.
1538 * This should be the path for all ptrace stops.
1539 * We always set current->last_siginfo while stopped here.
1540 * That makes it a way to test a stopped process for
1541 * being ptrace-stopped vs being job-control-stopped.
1543 * If we actually decide not to stop at all because the tracer
1544 * is gone, we keep current->exit_code unless clear_code.
1546 static void ptrace_stop(int exit_code
, int clear_code
, siginfo_t
*info
)
1548 if (arch_ptrace_stop_needed(exit_code
, info
)) {
1550 * The arch code has something special to do before a
1551 * ptrace stop. This is allowed to block, e.g. for faults
1552 * on user stack pages. We can't keep the siglock while
1553 * calling arch_ptrace_stop, so we must release it now.
1554 * To preserve proper semantics, we must do this before
1555 * any signal bookkeeping like checking group_stop_count.
1556 * Meanwhile, a SIGKILL could come in before we retake the
1557 * siglock. That must prevent us from sleeping in TASK_TRACED.
1558 * So after regaining the lock, we must check for SIGKILL.
1560 spin_unlock_irq(¤t
->sighand
->siglock
);
1561 arch_ptrace_stop(exit_code
, info
);
1562 spin_lock_irq(¤t
->sighand
->siglock
);
1563 if (sigkill_pending(current
))
1568 * If there is a group stop in progress,
1569 * we must participate in the bookkeeping.
1571 if (current
->signal
->group_stop_count
> 0)
1572 --current
->signal
->group_stop_count
;
1574 current
->last_siginfo
= info
;
1575 current
->exit_code
= exit_code
;
1577 /* Let the debugger run. */
1578 __set_current_state(TASK_TRACED
);
1579 spin_unlock_irq(¤t
->sighand
->siglock
);
1580 read_lock(&tasklist_lock
);
1581 if (may_ptrace_stop()) {
1582 do_notify_parent_cldstop(current
, CLD_TRAPPED
);
1584 * Don't want to allow preemption here, because
1585 * sys_ptrace() needs this task to be inactive.
1587 * XXX: implement read_unlock_no_resched().
1590 read_unlock(&tasklist_lock
);
1591 preempt_enable_no_resched();
1595 * By the time we got the lock, our tracer went away.
1596 * Don't drop the lock yet, another tracer may come.
1598 __set_current_state(TASK_RUNNING
);
1600 current
->exit_code
= 0;
1601 read_unlock(&tasklist_lock
);
1605 * While in TASK_TRACED, we were considered "frozen enough".
1606 * Now that we woke up, it's crucial if we're supposed to be
1607 * frozen that we freeze now before running anything substantial.
1612 * We are back. Now reacquire the siglock before touching
1613 * last_siginfo, so that we are sure to have synchronized with
1614 * any signal-sending on another CPU that wants to examine it.
1616 spin_lock_irq(¤t
->sighand
->siglock
);
1617 current
->last_siginfo
= NULL
;
1620 * Queued signals ignored us while we were stopped for tracing.
1621 * So check for any that we should take before resuming user mode.
1622 * This sets TIF_SIGPENDING, but never clears it.
1624 recalc_sigpending_tsk(current
);
1627 void ptrace_notify(int exit_code
)
1631 BUG_ON((exit_code
& (0x7f | ~0xffff)) != SIGTRAP
);
1633 memset(&info
, 0, sizeof info
);
1634 info
.si_signo
= SIGTRAP
;
1635 info
.si_code
= exit_code
;
1636 info
.si_pid
= task_pid_vnr(current
);
1637 info
.si_uid
= current_uid();
1639 /* Let the debugger run. */
1640 spin_lock_irq(¤t
->sighand
->siglock
);
1641 ptrace_stop(exit_code
, 1, &info
);
1642 spin_unlock_irq(¤t
->sighand
->siglock
);
1646 finish_stop(int stop_count
)
1649 * If there are no other threads in the group, or if there is
1650 * a group stop in progress and we are the last to stop,
1651 * report to the parent. When ptraced, every thread reports itself.
1653 if (tracehook_notify_jctl(stop_count
== 0, CLD_STOPPED
)) {
1654 read_lock(&tasklist_lock
);
1655 do_notify_parent_cldstop(current
, CLD_STOPPED
);
1656 read_unlock(&tasklist_lock
);
1661 } while (try_to_freeze());
1663 * Now we don't run again until continued.
1665 current
->exit_code
= 0;
1669 * This performs the stopping for SIGSTOP and other stop signals.
1670 * We have to stop all threads in the thread group.
1671 * Returns nonzero if we've actually stopped and released the siglock.
1672 * Returns zero if we didn't stop and still hold the siglock.
1674 static int do_signal_stop(int signr
)
1676 struct signal_struct
*sig
= current
->signal
;
1679 if (sig
->group_stop_count
> 0) {
1681 * There is a group stop in progress. We don't need to
1682 * start another one.
1684 stop_count
= --sig
->group_stop_count
;
1686 struct task_struct
*t
;
1688 if (!likely(sig
->flags
& SIGNAL_STOP_DEQUEUED
) ||
1689 unlikely(signal_group_exit(sig
)))
1692 * There is no group stop already in progress.
1693 * We must initiate one now.
1695 sig
->group_exit_code
= signr
;
1698 for (t
= next_thread(current
); t
!= current
; t
= next_thread(t
))
1700 * Setting state to TASK_STOPPED for a group
1701 * stop is always done with the siglock held,
1702 * so this check has no races.
1704 if (!(t
->flags
& PF_EXITING
) &&
1705 !task_is_stopped_or_traced(t
)) {
1707 signal_wake_up(t
, 0);
1709 sig
->group_stop_count
= stop_count
;
1712 if (stop_count
== 0)
1713 sig
->flags
= SIGNAL_STOP_STOPPED
;
1714 current
->exit_code
= sig
->group_exit_code
;
1715 __set_current_state(TASK_STOPPED
);
1717 spin_unlock_irq(¤t
->sighand
->siglock
);
1718 finish_stop(stop_count
);
1722 static int ptrace_signal(int signr
, siginfo_t
*info
,
1723 struct pt_regs
*regs
, void *cookie
)
1725 if (!(current
->ptrace
& PT_PTRACED
))
1728 ptrace_signal_deliver(regs
, cookie
);
1730 /* Let the debugger run. */
1731 ptrace_stop(signr
, 0, info
);
1733 /* We're back. Did the debugger cancel the sig? */
1734 signr
= current
->exit_code
;
1738 current
->exit_code
= 0;
1740 /* Update the siginfo structure if the signal has
1741 changed. If the debugger wanted something
1742 specific in the siginfo structure then it should
1743 have updated *info via PTRACE_SETSIGINFO. */
1744 if (signr
!= info
->si_signo
) {
1745 info
->si_signo
= signr
;
1747 info
->si_code
= SI_USER
;
1748 info
->si_pid
= task_pid_vnr(current
->parent
);
1749 info
->si_uid
= task_uid(current
->parent
);
1752 /* If the (new) signal is now blocked, requeue it. */
1753 if (sigismember(¤t
->blocked
, signr
)) {
1754 specific_send_sig_info(signr
, info
, current
);
1761 int get_signal_to_deliver(siginfo_t
*info
, struct k_sigaction
*return_ka
,
1762 struct pt_regs
*regs
, void *cookie
)
1764 struct sighand_struct
*sighand
= current
->sighand
;
1765 struct signal_struct
*signal
= current
->signal
;
1770 * We'll jump back here after any time we were stopped in TASK_STOPPED.
1771 * While in TASK_STOPPED, we were considered "frozen enough".
1772 * Now that we woke up, it's crucial if we're supposed to be
1773 * frozen that we freeze now before running anything substantial.
1777 spin_lock_irq(&sighand
->siglock
);
1779 * Every stopped thread goes here after wakeup. Check to see if
1780 * we should notify the parent, prepare_signal(SIGCONT) encodes
1781 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
1783 if (unlikely(signal
->flags
& SIGNAL_CLD_MASK
)) {
1784 int why
= (signal
->flags
& SIGNAL_STOP_CONTINUED
)
1785 ? CLD_CONTINUED
: CLD_STOPPED
;
1786 signal
->flags
&= ~SIGNAL_CLD_MASK
;
1787 spin_unlock_irq(&sighand
->siglock
);
1789 if (unlikely(!tracehook_notify_jctl(1, why
)))
1792 read_lock(&tasklist_lock
);
1793 do_notify_parent_cldstop(current
->group_leader
, why
);
1794 read_unlock(&tasklist_lock
);
1799 struct k_sigaction
*ka
;
1801 if (unlikely(signal
->group_stop_count
> 0) &&
1806 * Tracing can induce an artifical signal and choose sigaction.
1807 * The return value in @signr determines the default action,
1808 * but @info->si_signo is the signal number we will report.
1810 signr
= tracehook_get_signal(current
, regs
, info
, return_ka
);
1811 if (unlikely(signr
< 0))
1813 if (unlikely(signr
!= 0))
1816 signr
= dequeue_signal(current
, ¤t
->blocked
,
1820 break; /* will return 0 */
1822 if (signr
!= SIGKILL
) {
1823 signr
= ptrace_signal(signr
, info
,
1829 ka
= &sighand
->action
[signr
-1];
1832 if (ka
->sa
.sa_handler
== SIG_IGN
) /* Do nothing. */
1834 if (ka
->sa
.sa_handler
!= SIG_DFL
) {
1835 /* Run the handler. */
1838 if (ka
->sa
.sa_flags
& SA_ONESHOT
)
1839 ka
->sa
.sa_handler
= SIG_DFL
;
1841 break; /* will return non-zero "signr" value */
1845 * Now we are doing the default action for this signal.
1847 if (sig_kernel_ignore(signr
)) /* Default is nothing. */
1851 * Global init gets no signals it doesn't want.
1853 if (unlikely(signal
->flags
& SIGNAL_UNKILLABLE
) &&
1854 !signal_group_exit(signal
))
1857 if (sig_kernel_stop(signr
)) {
1859 * The default action is to stop all threads in
1860 * the thread group. The job control signals
1861 * do nothing in an orphaned pgrp, but SIGSTOP
1862 * always works. Note that siglock needs to be
1863 * dropped during the call to is_orphaned_pgrp()
1864 * because of lock ordering with tasklist_lock.
1865 * This allows an intervening SIGCONT to be posted.
1866 * We need to check for that and bail out if necessary.
1868 if (signr
!= SIGSTOP
) {
1869 spin_unlock_irq(&sighand
->siglock
);
1871 /* signals can be posted during this window */
1873 if (is_current_pgrp_orphaned())
1876 spin_lock_irq(&sighand
->siglock
);
1879 if (likely(do_signal_stop(info
->si_signo
))) {
1880 /* It released the siglock. */
1885 * We didn't actually stop, due to a race
1886 * with SIGCONT or something like that.
1891 spin_unlock_irq(&sighand
->siglock
);
1894 * Anything else is fatal, maybe with a core dump.
1896 current
->flags
|= PF_SIGNALED
;
1898 if (sig_kernel_coredump(signr
)) {
1899 if (print_fatal_signals
)
1900 print_fatal_signal(regs
, info
->si_signo
);
1902 * If it was able to dump core, this kills all
1903 * other threads in the group and synchronizes with
1904 * their demise. If we lost the race with another
1905 * thread getting here, it set group_exit_code
1906 * first and our do_group_exit call below will use
1907 * that value and ignore the one we pass it.
1909 do_coredump(info
->si_signo
, info
->si_signo
, regs
);
1913 * Death signals, no core dump.
1915 do_group_exit(info
->si_signo
);
1918 spin_unlock_irq(&sighand
->siglock
);
1922 void exit_signals(struct task_struct
*tsk
)
1925 struct task_struct
*t
;
1927 if (thread_group_empty(tsk
) || signal_group_exit(tsk
->signal
)) {
1928 tsk
->flags
|= PF_EXITING
;
1932 spin_lock_irq(&tsk
->sighand
->siglock
);
1934 * From now this task is not visible for group-wide signals,
1935 * see wants_signal(), do_signal_stop().
1937 tsk
->flags
|= PF_EXITING
;
1938 if (!signal_pending(tsk
))
1941 /* It could be that __group_complete_signal() choose us to
1942 * notify about group-wide signal. Another thread should be
1943 * woken now to take the signal since we will not.
1945 for (t
= tsk
; (t
= next_thread(t
)) != tsk
; )
1946 if (!signal_pending(t
) && !(t
->flags
& PF_EXITING
))
1947 recalc_sigpending_and_wake(t
);
1949 if (unlikely(tsk
->signal
->group_stop_count
) &&
1950 !--tsk
->signal
->group_stop_count
) {
1951 tsk
->signal
->flags
= SIGNAL_STOP_STOPPED
;
1955 spin_unlock_irq(&tsk
->sighand
->siglock
);
1957 if (unlikely(group_stop
) && tracehook_notify_jctl(1, CLD_STOPPED
)) {
1958 read_lock(&tasklist_lock
);
1959 do_notify_parent_cldstop(tsk
, CLD_STOPPED
);
1960 read_unlock(&tasklist_lock
);
1964 EXPORT_SYMBOL(recalc_sigpending
);
1965 EXPORT_SYMBOL_GPL(dequeue_signal
);
1966 EXPORT_SYMBOL(flush_signals
);
1967 EXPORT_SYMBOL(force_sig
);
1968 EXPORT_SYMBOL(send_sig
);
1969 EXPORT_SYMBOL(send_sig_info
);
1970 EXPORT_SYMBOL(sigprocmask
);
1971 EXPORT_SYMBOL(block_all_signals
);
1972 EXPORT_SYMBOL(unblock_all_signals
);
1976 * System call entry points.
1979 SYSCALL_DEFINE0(restart_syscall
)
1981 struct restart_block
*restart
= ¤t_thread_info()->restart_block
;
1982 return restart
->fn(restart
);
1985 long do_no_restart_syscall(struct restart_block
*param
)
1991 * We don't need to get the kernel lock - this is all local to this
1992 * particular thread.. (and that's good, because this is _heavily_
1993 * used by various programs)
1997 * This is also useful for kernel threads that want to temporarily
1998 * (or permanently) block certain signals.
2000 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2001 * interface happily blocks "unblockable" signals like SIGKILL
2004 int sigprocmask(int how
, sigset_t
*set
, sigset_t
*oldset
)
2008 spin_lock_irq(¤t
->sighand
->siglock
);
2010 *oldset
= current
->blocked
;
2015 sigorsets(¤t
->blocked
, ¤t
->blocked
, set
);
2018 signandsets(¤t
->blocked
, ¤t
->blocked
, set
);
2021 current
->blocked
= *set
;
2026 recalc_sigpending();
2027 spin_unlock_irq(¤t
->sighand
->siglock
);
2032 SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, sigset_t __user
*, set
,
2033 sigset_t __user
*, oset
, size_t, sigsetsize
)
2035 int error
= -EINVAL
;
2036 sigset_t old_set
, new_set
;
2038 /* XXX: Don't preclude handling different sized sigset_t's. */
2039 if (sigsetsize
!= sizeof(sigset_t
))
2044 if (copy_from_user(&new_set
, set
, sizeof(*set
)))
2046 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2048 error
= sigprocmask(how
, &new_set
, &old_set
);
2054 spin_lock_irq(¤t
->sighand
->siglock
);
2055 old_set
= current
->blocked
;
2056 spin_unlock_irq(¤t
->sighand
->siglock
);
2060 if (copy_to_user(oset
, &old_set
, sizeof(*oset
)))
2068 long do_sigpending(void __user
*set
, unsigned long sigsetsize
)
2070 long error
= -EINVAL
;
2073 if (sigsetsize
> sizeof(sigset_t
))
2076 spin_lock_irq(¤t
->sighand
->siglock
);
2077 sigorsets(&pending
, ¤t
->pending
.signal
,
2078 ¤t
->signal
->shared_pending
.signal
);
2079 spin_unlock_irq(¤t
->sighand
->siglock
);
2081 /* Outside the lock because only this thread touches it. */
2082 sigandsets(&pending
, ¤t
->blocked
, &pending
);
2085 if (!copy_to_user(set
, &pending
, sigsetsize
))
2092 SYSCALL_DEFINE2(rt_sigpending
, sigset_t __user
*, set
, size_t, sigsetsize
)
2094 return do_sigpending(set
, sigsetsize
);
2097 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2099 int copy_siginfo_to_user(siginfo_t __user
*to
, siginfo_t
*from
)
2103 if (!access_ok (VERIFY_WRITE
, to
, sizeof(siginfo_t
)))
2105 if (from
->si_code
< 0)
2106 return __copy_to_user(to
, from
, sizeof(siginfo_t
))
2109 * If you change siginfo_t structure, please be sure
2110 * this code is fixed accordingly.
2111 * Please remember to update the signalfd_copyinfo() function
2112 * inside fs/signalfd.c too, in case siginfo_t changes.
2113 * It should never copy any pad contained in the structure
2114 * to avoid security leaks, but must copy the generic
2115 * 3 ints plus the relevant union member.
2117 err
= __put_user(from
->si_signo
, &to
->si_signo
);
2118 err
|= __put_user(from
->si_errno
, &to
->si_errno
);
2119 err
|= __put_user((short)from
->si_code
, &to
->si_code
);
2120 switch (from
->si_code
& __SI_MASK
) {
2122 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2123 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2126 err
|= __put_user(from
->si_tid
, &to
->si_tid
);
2127 err
|= __put_user(from
->si_overrun
, &to
->si_overrun
);
2128 err
|= __put_user(from
->si_ptr
, &to
->si_ptr
);
2131 err
|= __put_user(from
->si_band
, &to
->si_band
);
2132 err
|= __put_user(from
->si_fd
, &to
->si_fd
);
2135 err
|= __put_user(from
->si_addr
, &to
->si_addr
);
2136 #ifdef __ARCH_SI_TRAPNO
2137 err
|= __put_user(from
->si_trapno
, &to
->si_trapno
);
2141 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2142 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2143 err
|= __put_user(from
->si_status
, &to
->si_status
);
2144 err
|= __put_user(from
->si_utime
, &to
->si_utime
);
2145 err
|= __put_user(from
->si_stime
, &to
->si_stime
);
2147 case __SI_RT
: /* This is not generated by the kernel as of now. */
2148 case __SI_MESGQ
: /* But this is */
2149 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2150 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2151 err
|= __put_user(from
->si_ptr
, &to
->si_ptr
);
2153 default: /* this is just in case for now ... */
2154 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2155 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2163 SYSCALL_DEFINE4(rt_sigtimedwait
, const sigset_t __user
*, uthese
,
2164 siginfo_t __user
*, uinfo
, const struct timespec __user
*, uts
,
2173 /* XXX: Don't preclude handling different sized sigset_t's. */
2174 if (sigsetsize
!= sizeof(sigset_t
))
2177 if (copy_from_user(&these
, uthese
, sizeof(these
)))
2181 * Invert the set of allowed signals to get those we
2184 sigdelsetmask(&these
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2188 if (copy_from_user(&ts
, uts
, sizeof(ts
)))
2190 if (ts
.tv_nsec
>= 1000000000L || ts
.tv_nsec
< 0
2195 spin_lock_irq(¤t
->sighand
->siglock
);
2196 sig
= dequeue_signal(current
, &these
, &info
);
2198 timeout
= MAX_SCHEDULE_TIMEOUT
;
2200 timeout
= (timespec_to_jiffies(&ts
)
2201 + (ts
.tv_sec
|| ts
.tv_nsec
));
2204 /* None ready -- temporarily unblock those we're
2205 * interested while we are sleeping in so that we'll
2206 * be awakened when they arrive. */
2207 current
->real_blocked
= current
->blocked
;
2208 sigandsets(¤t
->blocked
, ¤t
->blocked
, &these
);
2209 recalc_sigpending();
2210 spin_unlock_irq(¤t
->sighand
->siglock
);
2212 timeout
= schedule_timeout_interruptible(timeout
);
2214 spin_lock_irq(¤t
->sighand
->siglock
);
2215 sig
= dequeue_signal(current
, &these
, &info
);
2216 current
->blocked
= current
->real_blocked
;
2217 siginitset(¤t
->real_blocked
, 0);
2218 recalc_sigpending();
2221 spin_unlock_irq(¤t
->sighand
->siglock
);
2226 if (copy_siginfo_to_user(uinfo
, &info
))
2238 SYSCALL_DEFINE2(kill
, pid_t
, pid
, int, sig
)
2240 struct siginfo info
;
2242 info
.si_signo
= sig
;
2244 info
.si_code
= SI_USER
;
2245 info
.si_pid
= task_tgid_vnr(current
);
2246 info
.si_uid
= current_uid();
2248 return kill_something_info(sig
, &info
, pid
);
2251 static int do_tkill(pid_t tgid
, pid_t pid
, int sig
)
2254 struct siginfo info
;
2255 struct task_struct
*p
;
2256 unsigned long flags
;
2259 info
.si_signo
= sig
;
2261 info
.si_code
= SI_TKILL
;
2262 info
.si_pid
= task_tgid_vnr(current
);
2263 info
.si_uid
= current_uid();
2266 p
= find_task_by_vpid(pid
);
2267 if (p
&& (tgid
<= 0 || task_tgid_vnr(p
) == tgid
)) {
2268 error
= check_kill_permission(sig
, &info
, p
);
2270 * The null signal is a permissions and process existence
2271 * probe. No signal is actually delivered.
2273 * If lock_task_sighand() fails we pretend the task dies
2274 * after receiving the signal. The window is tiny, and the
2275 * signal is private anyway.
2277 if (!error
&& sig
&& lock_task_sighand(p
, &flags
)) {
2278 error
= specific_send_sig_info(sig
, &info
, p
);
2279 unlock_task_sighand(p
, &flags
);
2288 * sys_tgkill - send signal to one specific thread
2289 * @tgid: the thread group ID of the thread
2290 * @pid: the PID of the thread
2291 * @sig: signal to be sent
2293 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2294 * exists but it's not belonging to the target process anymore. This
2295 * method solves the problem of threads exiting and PIDs getting reused.
2297 SYSCALL_DEFINE3(tgkill
, pid_t
, tgid
, pid_t
, pid
, int, sig
)
2299 /* This is only valid for single tasks */
2300 if (pid
<= 0 || tgid
<= 0)
2303 return do_tkill(tgid
, pid
, sig
);
2307 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2309 SYSCALL_DEFINE2(tkill
, pid_t
, pid
, int, sig
)
2311 /* This is only valid for single tasks */
2315 return do_tkill(0, pid
, sig
);
2318 SYSCALL_DEFINE3(rt_sigqueueinfo
, pid_t
, pid
, int, sig
,
2319 siginfo_t __user
*, uinfo
)
2323 if (copy_from_user(&info
, uinfo
, sizeof(siginfo_t
)))
2326 /* Not even root can pretend to send signals from the kernel.
2327 Nor can they impersonate a kill(), which adds source info. */
2328 if (info
.si_code
>= 0)
2330 info
.si_signo
= sig
;
2332 /* POSIX.1b doesn't mention process groups. */
2333 return kill_proc_info(sig
, &info
, pid
);
2336 int do_sigaction(int sig
, struct k_sigaction
*act
, struct k_sigaction
*oact
)
2338 struct task_struct
*t
= current
;
2339 struct k_sigaction
*k
;
2342 if (!valid_signal(sig
) || sig
< 1 || (act
&& sig_kernel_only(sig
)))
2345 k
= &t
->sighand
->action
[sig
-1];
2347 spin_lock_irq(¤t
->sighand
->siglock
);
2352 sigdelsetmask(&act
->sa
.sa_mask
,
2353 sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2357 * "Setting a signal action to SIG_IGN for a signal that is
2358 * pending shall cause the pending signal to be discarded,
2359 * whether or not it is blocked."
2361 * "Setting a signal action to SIG_DFL for a signal that is
2362 * pending and whose default action is to ignore the signal
2363 * (for example, SIGCHLD), shall cause the pending signal to
2364 * be discarded, whether or not it is blocked"
2366 if (sig_handler_ignored(sig_handler(t
, sig
), sig
)) {
2368 sigaddset(&mask
, sig
);
2369 rm_from_queue_full(&mask
, &t
->signal
->shared_pending
);
2371 rm_from_queue_full(&mask
, &t
->pending
);
2373 } while (t
!= current
);
2377 spin_unlock_irq(¤t
->sighand
->siglock
);
2382 do_sigaltstack (const stack_t __user
*uss
, stack_t __user
*uoss
, unsigned long sp
)
2388 oss
.ss_sp
= (void __user
*) current
->sas_ss_sp
;
2389 oss
.ss_size
= current
->sas_ss_size
;
2390 oss
.ss_flags
= sas_ss_flags(sp
);
2399 if (!access_ok(VERIFY_READ
, uss
, sizeof(*uss
))
2400 || __get_user(ss_sp
, &uss
->ss_sp
)
2401 || __get_user(ss_flags
, &uss
->ss_flags
)
2402 || __get_user(ss_size
, &uss
->ss_size
))
2406 if (on_sig_stack(sp
))
2412 * Note - this code used to test ss_flags incorrectly
2413 * old code may have been written using ss_flags==0
2414 * to mean ss_flags==SS_ONSTACK (as this was the only
2415 * way that worked) - this fix preserves that older
2418 if (ss_flags
!= SS_DISABLE
&& ss_flags
!= SS_ONSTACK
&& ss_flags
!= 0)
2421 if (ss_flags
== SS_DISABLE
) {
2426 if (ss_size
< MINSIGSTKSZ
)
2430 current
->sas_ss_sp
= (unsigned long) ss_sp
;
2431 current
->sas_ss_size
= ss_size
;
2436 if (copy_to_user(uoss
, &oss
, sizeof(oss
)))
2445 #ifdef __ARCH_WANT_SYS_SIGPENDING
2447 SYSCALL_DEFINE1(sigpending
, old_sigset_t __user
*, set
)
2449 return do_sigpending(set
, sizeof(*set
));
2454 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
2455 /* Some platforms have their own version with special arguments others
2456 support only sys_rt_sigprocmask. */
2458 SYSCALL_DEFINE3(sigprocmask
, int, how
, old_sigset_t __user
*, set
,
2459 old_sigset_t __user
*, oset
)
2462 old_sigset_t old_set
, new_set
;
2466 if (copy_from_user(&new_set
, set
, sizeof(*set
)))
2468 new_set
&= ~(sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2470 spin_lock_irq(¤t
->sighand
->siglock
);
2471 old_set
= current
->blocked
.sig
[0];
2479 sigaddsetmask(¤t
->blocked
, new_set
);
2482 sigdelsetmask(¤t
->blocked
, new_set
);
2485 current
->blocked
.sig
[0] = new_set
;
2489 recalc_sigpending();
2490 spin_unlock_irq(¤t
->sighand
->siglock
);
2496 old_set
= current
->blocked
.sig
[0];
2499 if (copy_to_user(oset
, &old_set
, sizeof(*oset
)))
2506 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
2508 #ifdef __ARCH_WANT_SYS_RT_SIGACTION
2509 SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
2510 const struct sigaction __user
*, act
,
2511 struct sigaction __user
*, oact
,
2514 struct k_sigaction new_sa
, old_sa
;
2517 /* XXX: Don't preclude handling different sized sigset_t's. */
2518 if (sigsetsize
!= sizeof(sigset_t
))
2522 if (copy_from_user(&new_sa
.sa
, act
, sizeof(new_sa
.sa
)))
2526 ret
= do_sigaction(sig
, act
? &new_sa
: NULL
, oact
? &old_sa
: NULL
);
2529 if (copy_to_user(oact
, &old_sa
.sa
, sizeof(old_sa
.sa
)))
2535 #endif /* __ARCH_WANT_SYS_RT_SIGACTION */
2537 #ifdef __ARCH_WANT_SYS_SGETMASK
2540 * For backwards compatibility. Functionality superseded by sigprocmask.
2542 SYSCALL_DEFINE0(sgetmask
)
2545 return current
->blocked
.sig
[0];
2548 SYSCALL_DEFINE1(ssetmask
, int, newmask
)
2552 spin_lock_irq(¤t
->sighand
->siglock
);
2553 old
= current
->blocked
.sig
[0];
2555 siginitset(¤t
->blocked
, newmask
& ~(sigmask(SIGKILL
)|
2557 recalc_sigpending();
2558 spin_unlock_irq(¤t
->sighand
->siglock
);
2562 #endif /* __ARCH_WANT_SGETMASK */
2564 #ifdef __ARCH_WANT_SYS_SIGNAL
2566 * For backwards compatibility. Functionality superseded by sigaction.
2568 SYSCALL_DEFINE2(signal
, int, sig
, __sighandler_t
, handler
)
2570 struct k_sigaction new_sa
, old_sa
;
2573 new_sa
.sa
.sa_handler
= handler
;
2574 new_sa
.sa
.sa_flags
= SA_ONESHOT
| SA_NOMASK
;
2575 sigemptyset(&new_sa
.sa
.sa_mask
);
2577 ret
= do_sigaction(sig
, &new_sa
, &old_sa
);
2579 return ret
? ret
: (unsigned long)old_sa
.sa
.sa_handler
;
2581 #endif /* __ARCH_WANT_SYS_SIGNAL */
2583 #ifdef __ARCH_WANT_SYS_PAUSE
2585 SYSCALL_DEFINE0(pause
)
2587 current
->state
= TASK_INTERRUPTIBLE
;
2589 return -ERESTARTNOHAND
;
2594 #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
2595 SYSCALL_DEFINE2(rt_sigsuspend
, sigset_t __user
*, unewset
, size_t, sigsetsize
)
2599 /* XXX: Don't preclude handling different sized sigset_t's. */
2600 if (sigsetsize
!= sizeof(sigset_t
))
2603 if (copy_from_user(&newset
, unewset
, sizeof(newset
)))
2605 sigdelsetmask(&newset
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2607 spin_lock_irq(¤t
->sighand
->siglock
);
2608 current
->saved_sigmask
= current
->blocked
;
2609 current
->blocked
= newset
;
2610 recalc_sigpending();
2611 spin_unlock_irq(¤t
->sighand
->siglock
);
2613 current
->state
= TASK_INTERRUPTIBLE
;
2615 set_restore_sigmask();
2616 return -ERESTARTNOHAND
;
2618 #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
2620 __attribute__((weak
)) const char *arch_vma_name(struct vm_area_struct
*vma
)
2625 void __init
signals_init(void)
2627 sigqueue_cachep
= KMEM_CACHE(sigqueue
, SLAB_PANIC
);