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/export.h>
15 #include <linux/init.h>
16 #include <linux/sched.h>
18 #include <linux/tty.h>
19 #include <linux/binfmts.h>
20 #include <linux/coredump.h>
21 #include <linux/security.h>
22 #include <linux/syscalls.h>
23 #include <linux/ptrace.h>
24 #include <linux/signal.h>
25 #include <linux/signalfd.h>
26 #include <linux/ratelimit.h>
27 #include <linux/tracehook.h>
28 #include <linux/capability.h>
29 #include <linux/freezer.h>
30 #include <linux/pid_namespace.h>
31 #include <linux/nsproxy.h>
32 #include <linux/user_namespace.h>
33 #include <linux/uprobes.h>
34 #include <linux/compat.h>
35 #include <linux/cn_proc.h>
36 #include <linux/compiler.h>
38 #define CREATE_TRACE_POINTS
39 #include <trace/events/signal.h>
41 #include <asm/param.h>
42 #include <asm/uaccess.h>
43 #include <asm/unistd.h>
44 #include <asm/siginfo.h>
45 #include <asm/cacheflush.h>
46 #include "audit.h" /* audit_signal_info() */
49 * SLAB caches for signal bits.
52 static struct kmem_cache *sigqueue_cachep;
54 int print_fatal_signals __read_mostly;
56 static void __user *sig_handler(struct task_struct *t, int sig)
58 return t->sighand->action[sig - 1].sa.sa_handler;
61 static int sig_handler_ignored(void __user *handler, int sig)
63 /* Is it explicitly or implicitly ignored? */
64 return handler == SIG_IGN ||
65 (handler == SIG_DFL && sig_kernel_ignore(sig));
68 static int sig_task_ignored(struct task_struct *t, int sig, bool force)
72 handler = sig_handler(t, sig);
74 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
75 handler == SIG_DFL && !force)
78 return sig_handler_ignored(handler, sig);
81 static int sig_ignored(struct task_struct *t, int sig, bool force)
84 * Blocked signals are never ignored, since the
85 * signal handler may change by the time it is
88 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
91 if (!sig_task_ignored(t, sig, force))
95 * Tracers may want to know about even ignored signals.
101 * Re-calculate pending state from the set of locally pending
102 * signals, globally pending signals, and blocked signals.
104 static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
109 switch (_NSIG_WORDS) {
111 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
112 ready |= signal->sig[i] &~ blocked->sig[i];
115 case 4: ready = signal->sig[3] &~ blocked->sig[3];
116 ready |= signal->sig[2] &~ blocked->sig[2];
117 ready |= signal->sig[1] &~ blocked->sig[1];
118 ready |= signal->sig[0] &~ blocked->sig[0];
121 case 2: ready = signal->sig[1] &~ blocked->sig[1];
122 ready |= signal->sig[0] &~ blocked->sig[0];
125 case 1: ready = signal->sig[0] &~ blocked->sig[0];
130 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
132 static int recalc_sigpending_tsk(struct task_struct *t)
134 if ((t->jobctl & JOBCTL_PENDING_MASK) ||
135 PENDING(&t->pending, &t->blocked) ||
136 PENDING(&t->signal->shared_pending, &t->blocked)) {
137 set_tsk_thread_flag(t, TIF_SIGPENDING);
141 * We must never clear the flag in another thread, or in current
142 * when it's possible the current syscall is returning -ERESTART*.
143 * So we don't clear it here, and only callers who know they should do.
149 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
150 * This is superfluous when called on current, the wakeup is a harmless no-op.
152 void recalc_sigpending_and_wake(struct task_struct *t)
154 if (recalc_sigpending_tsk(t))
155 signal_wake_up(t, 0);
158 void recalc_sigpending(void)
160 if (!recalc_sigpending_tsk(current) && !freezing(current))
161 clear_thread_flag(TIF_SIGPENDING);
165 /* Given the mask, find the first available signal that should be serviced. */
167 #define SYNCHRONOUS_MASK \
168 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
169 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
171 int next_signal(struct sigpending *pending, sigset_t *mask)
173 unsigned long i, *s, *m, x;
176 s = pending->signal.sig;
180 * Handle the first word specially: it contains the
181 * synchronous signals that need to be dequeued first.
185 if (x & SYNCHRONOUS_MASK)
186 x &= SYNCHRONOUS_MASK;
191 switch (_NSIG_WORDS) {
193 for (i = 1; i < _NSIG_WORDS; ++i) {
197 sig = ffz(~x) + i*_NSIG_BPW + 1;
206 sig = ffz(~x) + _NSIG_BPW + 1;
217 static inline void print_dropped_signal(int sig)
219 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
221 if (!print_fatal_signals)
224 if (!__ratelimit(&ratelimit_state))
227 printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
228 current->comm, current->pid, sig);
232 * task_set_jobctl_pending - set jobctl pending bits
234 * @mask: pending bits to set
236 * Clear @mask from @task->jobctl. @mask must be subset of
237 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
238 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
239 * cleared. If @task is already being killed or exiting, this function
243 * Must be called with @task->sighand->siglock held.
246 * %true if @mask is set, %false if made noop because @task was dying.
248 bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask)
250 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
251 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
252 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
254 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
257 if (mask & JOBCTL_STOP_SIGMASK)
258 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
260 task->jobctl |= mask;
265 * task_clear_jobctl_trapping - clear jobctl trapping bit
268 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
269 * Clear it and wake up the ptracer. Note that we don't need any further
270 * locking. @task->siglock guarantees that @task->parent points to the
274 * Must be called with @task->sighand->siglock held.
276 void task_clear_jobctl_trapping(struct task_struct *task)
278 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
279 task->jobctl &= ~JOBCTL_TRAPPING;
280 smp_mb(); /* advised by wake_up_bit() */
281 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
286 * task_clear_jobctl_pending - clear jobctl pending bits
288 * @mask: pending bits to clear
290 * Clear @mask from @task->jobctl. @mask must be subset of
291 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
292 * STOP bits are cleared together.
294 * If clearing of @mask leaves no stop or trap pending, this function calls
295 * task_clear_jobctl_trapping().
298 * Must be called with @task->sighand->siglock held.
300 void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask)
302 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
304 if (mask & JOBCTL_STOP_PENDING)
305 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
307 task->jobctl &= ~mask;
309 if (!(task->jobctl & JOBCTL_PENDING_MASK))
310 task_clear_jobctl_trapping(task);
314 * task_participate_group_stop - participate in a group stop
315 * @task: task participating in a group stop
317 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
318 * Group stop states are cleared and the group stop count is consumed if
319 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
320 * stop, the appropriate %SIGNAL_* flags are set.
323 * Must be called with @task->sighand->siglock held.
326 * %true if group stop completion should be notified to the parent, %false
329 static bool task_participate_group_stop(struct task_struct *task)
331 struct signal_struct *sig = task->signal;
332 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
334 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
336 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
341 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
342 sig->group_stop_count--;
345 * Tell the caller to notify completion iff we are entering into a
346 * fresh group stop. Read comment in do_signal_stop() for details.
348 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
349 sig->flags = SIGNAL_STOP_STOPPED;
356 * allocate a new signal queue record
357 * - this may be called without locks if and only if t == current, otherwise an
358 * appropriate lock must be held to stop the target task from exiting
360 static struct sigqueue *
361 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
363 struct sigqueue *q = NULL;
364 struct user_struct *user;
367 * Protect access to @t credentials. This can go away when all
368 * callers hold rcu read lock.
371 user = get_uid(__task_cred(t)->user);
372 atomic_inc(&user->sigpending);
375 if (override_rlimit ||
376 atomic_read(&user->sigpending) <=
377 task_rlimit(t, RLIMIT_SIGPENDING)) {
378 q = kmem_cache_alloc(sigqueue_cachep, flags);
380 print_dropped_signal(sig);
383 if (unlikely(q == NULL)) {
384 atomic_dec(&user->sigpending);
387 INIT_LIST_HEAD(&q->list);
395 static void __sigqueue_free(struct sigqueue *q)
397 if (q->flags & SIGQUEUE_PREALLOC)
399 atomic_dec(&q->user->sigpending);
401 kmem_cache_free(sigqueue_cachep, q);
404 void flush_sigqueue(struct sigpending *queue)
408 sigemptyset(&queue->signal);
409 while (!list_empty(&queue->list)) {
410 q = list_entry(queue->list.next, struct sigqueue , list);
411 list_del_init(&q->list);
417 * Flush all pending signals for a task.
419 void __flush_signals(struct task_struct *t)
421 clear_tsk_thread_flag(t, TIF_SIGPENDING);
422 flush_sigqueue(&t->pending);
423 flush_sigqueue(&t->signal->shared_pending);
426 void flush_signals(struct task_struct *t)
430 spin_lock_irqsave(&t->sighand->siglock, flags);
432 spin_unlock_irqrestore(&t->sighand->siglock, flags);
435 static void __flush_itimer_signals(struct sigpending *pending)
437 sigset_t signal, retain;
438 struct sigqueue *q, *n;
440 signal = pending->signal;
441 sigemptyset(&retain);
443 list_for_each_entry_safe(q, n, &pending->list, list) {
444 int sig = q->info.si_signo;
446 if (likely(q->info.si_code != SI_TIMER)) {
447 sigaddset(&retain, sig);
449 sigdelset(&signal, sig);
450 list_del_init(&q->list);
455 sigorsets(&pending->signal, &signal, &retain);
458 void flush_itimer_signals(void)
460 struct task_struct *tsk = current;
463 spin_lock_irqsave(&tsk->sighand->siglock, flags);
464 __flush_itimer_signals(&tsk->pending);
465 __flush_itimer_signals(&tsk->signal->shared_pending);
466 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
469 void ignore_signals(struct task_struct *t)
473 for (i = 0; i < _NSIG; ++i)
474 t->sighand->action[i].sa.sa_handler = SIG_IGN;
480 * Flush all handlers for a task.
484 flush_signal_handlers(struct task_struct *t, int force_default)
487 struct k_sigaction *ka = &t->sighand->action[0];
488 for (i = _NSIG ; i != 0 ; i--) {
489 if (force_default || ka->sa.sa_handler != SIG_IGN)
490 ka->sa.sa_handler = SIG_DFL;
492 #ifdef __ARCH_HAS_SA_RESTORER
493 ka->sa.sa_restorer = NULL;
495 sigemptyset(&ka->sa.sa_mask);
500 int unhandled_signal(struct task_struct *tsk, int sig)
502 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
503 if (is_global_init(tsk))
505 if (handler != SIG_IGN && handler != SIG_DFL)
507 /* if ptraced, let the tracer determine */
512 * Notify the system that a driver wants to block all signals for this
513 * process, and wants to be notified if any signals at all were to be
514 * sent/acted upon. If the notifier routine returns non-zero, then the
515 * signal will be acted upon after all. If the notifier routine returns 0,
516 * then then signal will be blocked. Only one block per process is
517 * allowed. priv is a pointer to private data that the notifier routine
518 * can use to determine if the signal should be blocked or not.
521 block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
525 spin_lock_irqsave(¤t->sighand->siglock, flags);
526 current->notifier_mask = mask;
527 current->notifier_data = priv;
528 current->notifier = notifier;
529 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
532 /* Notify the system that blocking has ended. */
535 unblock_all_signals(void)
539 spin_lock_irqsave(¤t->sighand->siglock, flags);
540 current->notifier = NULL;
541 current->notifier_data = NULL;
543 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
546 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
548 struct sigqueue *q, *first = NULL;
551 * Collect the siginfo appropriate to this signal. Check if
552 * there is another siginfo for the same signal.
554 list_for_each_entry(q, &list->list, list) {
555 if (q->info.si_signo == sig) {
562 sigdelset(&list->signal, sig);
566 list_del_init(&first->list);
567 copy_siginfo(info, &first->info);
568 __sigqueue_free(first);
571 * Ok, it wasn't in the queue. This must be
572 * a fast-pathed signal or we must have been
573 * out of queue space. So zero out the info.
575 info->si_signo = sig;
577 info->si_code = SI_USER;
583 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
586 int sig = next_signal(pending, mask);
589 if (current->notifier) {
590 if (sigismember(current->notifier_mask, sig)) {
591 if (!(current->notifier)(current->notifier_data)) {
592 clear_thread_flag(TIF_SIGPENDING);
598 collect_signal(sig, pending, info);
605 * Dequeue a signal and return the element to the caller, which is
606 * expected to free it.
608 * All callers have to hold the siglock.
610 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
614 /* We only dequeue private signals from ourselves, we don't let
615 * signalfd steal them
617 signr = __dequeue_signal(&tsk->pending, mask, info);
619 signr = __dequeue_signal(&tsk->signal->shared_pending,
624 * itimers are process shared and we restart periodic
625 * itimers in the signal delivery path to prevent DoS
626 * attacks in the high resolution timer case. This is
627 * compliant with the old way of self-restarting
628 * itimers, as the SIGALRM is a legacy signal and only
629 * queued once. Changing the restart behaviour to
630 * restart the timer in the signal dequeue path is
631 * reducing the timer noise on heavy loaded !highres
634 if (unlikely(signr == SIGALRM)) {
635 struct hrtimer *tmr = &tsk->signal->real_timer;
637 if (!hrtimer_is_queued(tmr) &&
638 tsk->signal->it_real_incr.tv64 != 0) {
639 hrtimer_forward(tmr, tmr->base->get_time(),
640 tsk->signal->it_real_incr);
641 hrtimer_restart(tmr);
650 if (unlikely(sig_kernel_stop(signr))) {
652 * Set a marker that we have dequeued a stop signal. Our
653 * caller might release the siglock and then the pending
654 * stop signal it is about to process is no longer in the
655 * pending bitmasks, but must still be cleared by a SIGCONT
656 * (and overruled by a SIGKILL). So those cases clear this
657 * shared flag after we've set it. Note that this flag may
658 * remain set after the signal we return is ignored or
659 * handled. That doesn't matter because its only purpose
660 * is to alert stop-signal processing code when another
661 * processor has come along and cleared the flag.
663 current->jobctl |= JOBCTL_STOP_DEQUEUED;
665 if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
667 * Release the siglock to ensure proper locking order
668 * of timer locks outside of siglocks. Note, we leave
669 * irqs disabled here, since the posix-timers code is
670 * about to disable them again anyway.
672 spin_unlock(&tsk->sighand->siglock);
673 do_schedule_next_timer(info);
674 spin_lock(&tsk->sighand->siglock);
680 * Tell a process that it has a new active signal..
682 * NOTE! we rely on the previous spin_lock to
683 * lock interrupts for us! We can only be called with
684 * "siglock" held, and the local interrupt must
685 * have been disabled when that got acquired!
687 * No need to set need_resched since signal event passing
688 * goes through ->blocked
690 void signal_wake_up_state(struct task_struct *t, unsigned int state)
692 set_tsk_thread_flag(t, TIF_SIGPENDING);
694 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
695 * case. We don't check t->state here because there is a race with it
696 * executing another processor and just now entering stopped state.
697 * By using wake_up_state, we ensure the process will wake up and
698 * handle its death signal.
700 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
705 * Remove signals in mask from the pending set and queue.
706 * Returns 1 if any signals were found.
708 * All callers must be holding the siglock.
710 static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
712 struct sigqueue *q, *n;
715 sigandsets(&m, mask, &s->signal);
716 if (sigisemptyset(&m))
719 sigandnsets(&s->signal, &s->signal, mask);
720 list_for_each_entry_safe(q, n, &s->list, list) {
721 if (sigismember(mask, q->info.si_signo)) {
722 list_del_init(&q->list);
729 static inline int is_si_special(const struct siginfo *info)
731 return info <= SEND_SIG_FORCED;
734 static inline bool si_fromuser(const struct siginfo *info)
736 return info == SEND_SIG_NOINFO ||
737 (!is_si_special(info) && SI_FROMUSER(info));
741 * called with RCU read lock from check_kill_permission()
743 static int kill_ok_by_cred(struct task_struct *t)
745 const struct cred *cred = current_cred();
746 const struct cred *tcred = __task_cred(t);
748 if (uid_eq(cred->euid, tcred->suid) ||
749 uid_eq(cred->euid, tcred->uid) ||
750 uid_eq(cred->uid, tcred->suid) ||
751 uid_eq(cred->uid, tcred->uid))
754 if (ns_capable(tcred->user_ns, CAP_KILL))
761 * Bad permissions for sending the signal
762 * - the caller must hold the RCU read lock
764 static int check_kill_permission(int sig, struct siginfo *info,
765 struct task_struct *t)
770 if (!valid_signal(sig))
773 if (!si_fromuser(info))
776 error = audit_signal_info(sig, t); /* Let audit system see the signal */
780 if (!same_thread_group(current, t) &&
781 !kill_ok_by_cred(t)) {
784 sid = task_session(t);
786 * We don't return the error if sid == NULL. The
787 * task was unhashed, the caller must notice this.
789 if (!sid || sid == task_session(current))
796 return security_task_kill(t, info, sig, 0);
800 * ptrace_trap_notify - schedule trap to notify ptracer
801 * @t: tracee wanting to notify tracer
803 * This function schedules sticky ptrace trap which is cleared on the next
804 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
807 * If @t is running, STOP trap will be taken. If trapped for STOP and
808 * ptracer is listening for events, tracee is woken up so that it can
809 * re-trap for the new event. If trapped otherwise, STOP trap will be
810 * eventually taken without returning to userland after the existing traps
811 * are finished by PTRACE_CONT.
814 * Must be called with @task->sighand->siglock held.
816 static void ptrace_trap_notify(struct task_struct *t)
818 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
819 assert_spin_locked(&t->sighand->siglock);
821 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
822 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
826 * Handle magic process-wide effects of stop/continue signals. Unlike
827 * the signal actions, these happen immediately at signal-generation
828 * time regardless of blocking, ignoring, or handling. This does the
829 * actual continuing for SIGCONT, but not the actual stopping for stop
830 * signals. The process stop is done as a signal action for SIG_DFL.
832 * Returns true if the signal should be actually delivered, otherwise
833 * it should be dropped.
835 static bool prepare_signal(int sig, struct task_struct *p, bool force)
837 struct signal_struct *signal = p->signal;
838 struct task_struct *t;
841 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
842 if (signal->flags & SIGNAL_GROUP_COREDUMP)
843 return sig == SIGKILL;
845 * The process is in the middle of dying, nothing to do.
847 } else if (sig_kernel_stop(sig)) {
849 * This is a stop signal. Remove SIGCONT from all queues.
851 siginitset(&flush, sigmask(SIGCONT));
852 flush_sigqueue_mask(&flush, &signal->shared_pending);
853 for_each_thread(p, t)
854 flush_sigqueue_mask(&flush, &t->pending);
855 } else if (sig == SIGCONT) {
858 * Remove all stop signals from all queues, wake all threads.
860 siginitset(&flush, SIG_KERNEL_STOP_MASK);
861 flush_sigqueue_mask(&flush, &signal->shared_pending);
862 for_each_thread(p, t) {
863 flush_sigqueue_mask(&flush, &t->pending);
864 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
865 if (likely(!(t->ptrace & PT_SEIZED)))
866 wake_up_state(t, __TASK_STOPPED);
868 ptrace_trap_notify(t);
872 * Notify the parent with CLD_CONTINUED if we were stopped.
874 * If we were in the middle of a group stop, we pretend it
875 * was already finished, and then continued. Since SIGCHLD
876 * doesn't queue we report only CLD_STOPPED, as if the next
877 * CLD_CONTINUED was dropped.
880 if (signal->flags & SIGNAL_STOP_STOPPED)
881 why |= SIGNAL_CLD_CONTINUED;
882 else if (signal->group_stop_count)
883 why |= SIGNAL_CLD_STOPPED;
887 * The first thread which returns from do_signal_stop()
888 * will take ->siglock, notice SIGNAL_CLD_MASK, and
889 * notify its parent. See get_signal_to_deliver().
891 signal->flags = why | SIGNAL_STOP_CONTINUED;
892 signal->group_stop_count = 0;
893 signal->group_exit_code = 0;
897 return !sig_ignored(p, sig, force);
901 * Test if P wants to take SIG. After we've checked all threads with this,
902 * it's equivalent to finding no threads not blocking SIG. Any threads not
903 * blocking SIG were ruled out because they are not running and already
904 * have pending signals. Such threads will dequeue from the shared queue
905 * as soon as they're available, so putting the signal on the shared queue
906 * will be equivalent to sending it to one such thread.
908 static inline int wants_signal(int sig, struct task_struct *p)
910 if (sigismember(&p->blocked, sig))
912 if (p->flags & PF_EXITING)
916 if (task_is_stopped_or_traced(p))
918 return task_curr(p) || !signal_pending(p);
921 static void complete_signal(int sig, struct task_struct *p, int group)
923 struct signal_struct *signal = p->signal;
924 struct task_struct *t;
927 * Now find a thread we can wake up to take the signal off the queue.
929 * If the main thread wants the signal, it gets first crack.
930 * Probably the least surprising to the average bear.
932 if (wants_signal(sig, p))
934 else if (!group || thread_group_empty(p))
936 * There is just one thread and it does not need to be woken.
937 * It will dequeue unblocked signals before it runs again.
942 * Otherwise try to find a suitable thread.
944 t = signal->curr_target;
945 while (!wants_signal(sig, t)) {
947 if (t == signal->curr_target)
949 * No thread needs to be woken.
950 * Any eligible threads will see
951 * the signal in the queue soon.
955 signal->curr_target = t;
959 * Found a killable thread. If the signal will be fatal,
960 * then start taking the whole group down immediately.
962 if (sig_fatal(p, sig) &&
963 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
964 !sigismember(&t->real_blocked, sig) &&
965 (sig == SIGKILL || !t->ptrace)) {
967 * This signal will be fatal to the whole group.
969 if (!sig_kernel_coredump(sig)) {
971 * Start a group exit and wake everybody up.
972 * This way we don't have other threads
973 * running and doing things after a slower
974 * thread has the fatal signal pending.
976 signal->flags = SIGNAL_GROUP_EXIT;
977 signal->group_exit_code = sig;
978 signal->group_stop_count = 0;
981 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
982 sigaddset(&t->pending.signal, SIGKILL);
983 signal_wake_up(t, 1);
984 } while_each_thread(p, t);
990 * The signal is already in the shared-pending queue.
991 * Tell the chosen thread to wake up and dequeue it.
993 signal_wake_up(t, sig == SIGKILL);
997 static inline int legacy_queue(struct sigpending *signals, int sig)
999 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1002 #ifdef CONFIG_USER_NS
1003 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1005 if (current_user_ns() == task_cred_xxx(t, user_ns))
1008 if (SI_FROMKERNEL(info))
1012 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
1013 make_kuid(current_user_ns(), info->si_uid));
1017 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1023 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
1024 int group, int from_ancestor_ns)
1026 struct sigpending *pending;
1028 int override_rlimit;
1029 int ret = 0, result;
1031 assert_spin_locked(&t->sighand->siglock);
1033 result = TRACE_SIGNAL_IGNORED;
1034 if (!prepare_signal(sig, t,
1035 from_ancestor_ns || (info == SEND_SIG_FORCED)))
1038 pending = group ? &t->signal->shared_pending : &t->pending;
1040 * Short-circuit ignored signals and support queuing
1041 * exactly one non-rt signal, so that we can get more
1042 * detailed information about the cause of the signal.
1044 result = TRACE_SIGNAL_ALREADY_PENDING;
1045 if (legacy_queue(pending, sig))
1048 result = TRACE_SIGNAL_DELIVERED;
1050 * fast-pathed signals for kernel-internal things like SIGSTOP
1053 if (info == SEND_SIG_FORCED)
1057 * Real-time signals must be queued if sent by sigqueue, or
1058 * some other real-time mechanism. It is implementation
1059 * defined whether kill() does so. We attempt to do so, on
1060 * the principle of least surprise, but since kill is not
1061 * allowed to fail with EAGAIN when low on memory we just
1062 * make sure at least one signal gets delivered and don't
1063 * pass on the info struct.
1066 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1068 override_rlimit = 0;
1070 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
1073 list_add_tail(&q->list, &pending->list);
1074 switch ((unsigned long) info) {
1075 case (unsigned long) SEND_SIG_NOINFO:
1076 q->info.si_signo = sig;
1077 q->info.si_errno = 0;
1078 q->info.si_code = SI_USER;
1079 q->info.si_pid = task_tgid_nr_ns(current,
1080 task_active_pid_ns(t));
1081 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1083 case (unsigned long) SEND_SIG_PRIV:
1084 q->info.si_signo = sig;
1085 q->info.si_errno = 0;
1086 q->info.si_code = SI_KERNEL;
1091 copy_siginfo(&q->info, info);
1092 if (from_ancestor_ns)
1097 userns_fixup_signal_uid(&q->info, t);
1099 } else if (!is_si_special(info)) {
1100 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1102 * Queue overflow, abort. We may abort if the
1103 * signal was rt and sent by user using something
1104 * other than kill().
1106 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1111 * This is a silent loss of information. We still
1112 * send the signal, but the *info bits are lost.
1114 result = TRACE_SIGNAL_LOSE_INFO;
1119 signalfd_notify(t, sig);
1120 sigaddset(&pending->signal, sig);
1121 complete_signal(sig, t, group);
1123 trace_signal_generate(sig, info, t, group, result);
1127 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
1130 int from_ancestor_ns = 0;
1132 #ifdef CONFIG_PID_NS
1133 from_ancestor_ns = si_fromuser(info) &&
1134 !task_pid_nr_ns(current, task_active_pid_ns(t));
1137 return __send_signal(sig, info, t, group, from_ancestor_ns);
1140 static void print_fatal_signal(int signr)
1142 struct pt_regs *regs = signal_pt_regs();
1143 printk(KERN_INFO "potentially unexpected fatal signal %d.\n", signr);
1145 #if defined(__i386__) && !defined(__arch_um__)
1146 printk(KERN_INFO "code at %08lx: ", regs->ip);
1149 for (i = 0; i < 16; i++) {
1152 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1154 printk(KERN_CONT "%02x ", insn);
1157 printk(KERN_CONT "\n");
1164 static int __init setup_print_fatal_signals(char *str)
1166 get_option (&str, &print_fatal_signals);
1171 __setup("print-fatal-signals=", setup_print_fatal_signals);
1174 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1176 return send_signal(sig, info, p, 1);
1180 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1182 return send_signal(sig, info, t, 0);
1185 int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1188 unsigned long flags;
1191 if (lock_task_sighand(p, &flags)) {
1192 ret = send_signal(sig, info, p, group);
1193 unlock_task_sighand(p, &flags);
1200 * Force a signal that the process can't ignore: if necessary
1201 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1203 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1204 * since we do not want to have a signal handler that was blocked
1205 * be invoked when user space had explicitly blocked it.
1207 * We don't want to have recursive SIGSEGV's etc, for example,
1208 * that is why we also clear SIGNAL_UNKILLABLE.
1211 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1213 unsigned long int flags;
1214 int ret, blocked, ignored;
1215 struct k_sigaction *action;
1217 spin_lock_irqsave(&t->sighand->siglock, flags);
1218 action = &t->sighand->action[sig-1];
1219 ignored = action->sa.sa_handler == SIG_IGN;
1220 blocked = sigismember(&t->blocked, sig);
1221 if (blocked || ignored) {
1222 action->sa.sa_handler = SIG_DFL;
1224 sigdelset(&t->blocked, sig);
1225 recalc_sigpending_and_wake(t);
1228 if (action->sa.sa_handler == SIG_DFL)
1229 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1230 ret = specific_send_sig_info(sig, info, t);
1231 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1237 * Nuke all other threads in the group.
1239 int zap_other_threads(struct task_struct *p)
1241 struct task_struct *t = p;
1244 p->signal->group_stop_count = 0;
1246 while_each_thread(p, t) {
1247 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1250 /* Don't bother with already dead threads */
1253 sigaddset(&t->pending.signal, SIGKILL);
1254 signal_wake_up(t, 1);
1260 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1261 unsigned long *flags)
1263 struct sighand_struct *sighand;
1267 * Disable interrupts early to avoid deadlocks.
1268 * See rcu_read_unlock() comment header for details.
1270 local_irq_save(*flags);
1272 sighand = rcu_dereference(tsk->sighand);
1273 if (unlikely(sighand == NULL)) {
1275 local_irq_restore(*flags);
1279 * This sighand can be already freed and even reused, but
1280 * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which
1281 * initializes ->siglock: this slab can't go away, it has
1282 * the same object type, ->siglock can't be reinitialized.
1284 * We need to ensure that tsk->sighand is still the same
1285 * after we take the lock, we can race with de_thread() or
1286 * __exit_signal(). In the latter case the next iteration
1287 * must see ->sighand == NULL.
1289 spin_lock(&sighand->siglock);
1290 if (likely(sighand == tsk->sighand)) {
1294 spin_unlock(&sighand->siglock);
1296 local_irq_restore(*flags);
1303 * send signal info to all the members of a group
1305 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1310 ret = check_kill_permission(sig, info, p);
1314 ret = do_send_sig_info(sig, info, p, true);
1320 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1321 * control characters do (^C, ^Z etc)
1322 * - the caller must hold at least a readlock on tasklist_lock
1324 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1326 struct task_struct *p = NULL;
1327 int retval, success;
1331 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1332 int err = group_send_sig_info(sig, info, p);
1335 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1336 return success ? 0 : retval;
1339 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1342 struct task_struct *p;
1346 p = pid_task(pid, PIDTYPE_PID);
1348 error = group_send_sig_info(sig, info, p);
1350 if (likely(!p || error != -ESRCH))
1354 * The task was unhashed in between, try again. If it
1355 * is dead, pid_task() will return NULL, if we race with
1356 * de_thread() it will find the new leader.
1361 int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1365 error = kill_pid_info(sig, info, find_vpid(pid));
1370 static int kill_as_cred_perm(const struct cred *cred,
1371 struct task_struct *target)
1373 const struct cred *pcred = __task_cred(target);
1374 if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
1375 !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid))
1380 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1381 int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
1382 const struct cred *cred, u32 secid)
1385 struct task_struct *p;
1386 unsigned long flags;
1388 if (!valid_signal(sig))
1392 p = pid_task(pid, PIDTYPE_PID);
1397 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
1401 ret = security_task_kill(p, info, sig, secid);
1406 if (lock_task_sighand(p, &flags)) {
1407 ret = __send_signal(sig, info, p, 1, 0);
1408 unlock_task_sighand(p, &flags);
1416 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
1419 * kill_something_info() interprets pid in interesting ways just like kill(2).
1421 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1422 * is probably wrong. Should make it like BSD or SYSV.
1425 static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
1431 ret = kill_pid_info(sig, info, find_vpid(pid));
1436 read_lock(&tasklist_lock);
1438 ret = __kill_pgrp_info(sig, info,
1439 pid ? find_vpid(-pid) : task_pgrp(current));
1441 int retval = 0, count = 0;
1442 struct task_struct * p;
1444 for_each_process(p) {
1445 if (task_pid_vnr(p) > 1 &&
1446 !same_thread_group(p, current)) {
1447 int err = group_send_sig_info(sig, info, p);
1453 ret = count ? retval : -ESRCH;
1455 read_unlock(&tasklist_lock);
1461 * These are for backward compatibility with the rest of the kernel source.
1464 int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1467 * Make sure legacy kernel users don't send in bad values
1468 * (normal paths check this in check_kill_permission).
1470 if (!valid_signal(sig))
1473 return do_send_sig_info(sig, info, p, false);
1476 #define __si_special(priv) \
1477 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1480 send_sig(int sig, struct task_struct *p, int priv)
1482 return send_sig_info(sig, __si_special(priv), p);
1486 force_sig(int sig, struct task_struct *p)
1488 force_sig_info(sig, SEND_SIG_PRIV, p);
1492 * When things go south during signal handling, we
1493 * will force a SIGSEGV. And if the signal that caused
1494 * the problem was already a SIGSEGV, we'll want to
1495 * make sure we don't even try to deliver the signal..
1498 force_sigsegv(int sig, struct task_struct *p)
1500 if (sig == SIGSEGV) {
1501 unsigned long flags;
1502 spin_lock_irqsave(&p->sighand->siglock, flags);
1503 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1504 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1506 force_sig(SIGSEGV, p);
1510 int kill_pgrp(struct pid *pid, int sig, int priv)
1514 read_lock(&tasklist_lock);
1515 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1516 read_unlock(&tasklist_lock);
1520 EXPORT_SYMBOL(kill_pgrp);
1522 int kill_pid(struct pid *pid, int sig, int priv)
1524 return kill_pid_info(sig, __si_special(priv), pid);
1526 EXPORT_SYMBOL(kill_pid);
1529 * These functions support sending signals using preallocated sigqueue
1530 * structures. This is needed "because realtime applications cannot
1531 * afford to lose notifications of asynchronous events, like timer
1532 * expirations or I/O completions". In the case of POSIX Timers
1533 * we allocate the sigqueue structure from the timer_create. If this
1534 * allocation fails we are able to report the failure to the application
1535 * with an EAGAIN error.
1537 struct sigqueue *sigqueue_alloc(void)
1539 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1542 q->flags |= SIGQUEUE_PREALLOC;
1547 void sigqueue_free(struct sigqueue *q)
1549 unsigned long flags;
1550 spinlock_t *lock = ¤t->sighand->siglock;
1552 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1554 * We must hold ->siglock while testing q->list
1555 * to serialize with collect_signal() or with
1556 * __exit_signal()->flush_sigqueue().
1558 spin_lock_irqsave(lock, flags);
1559 q->flags &= ~SIGQUEUE_PREALLOC;
1561 * If it is queued it will be freed when dequeued,
1562 * like the "regular" sigqueue.
1564 if (!list_empty(&q->list))
1566 spin_unlock_irqrestore(lock, flags);
1572 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1574 int sig = q->info.si_signo;
1575 struct sigpending *pending;
1576 unsigned long flags;
1579 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1582 if (!likely(lock_task_sighand(t, &flags)))
1585 ret = 1; /* the signal is ignored */
1586 result = TRACE_SIGNAL_IGNORED;
1587 if (!prepare_signal(sig, t, false))
1591 if (unlikely(!list_empty(&q->list))) {
1593 * If an SI_TIMER entry is already queue just increment
1594 * the overrun count.
1596 BUG_ON(q->info.si_code != SI_TIMER);
1597 q->info.si_overrun++;
1598 result = TRACE_SIGNAL_ALREADY_PENDING;
1601 q->info.si_overrun = 0;
1603 signalfd_notify(t, sig);
1604 pending = group ? &t->signal->shared_pending : &t->pending;
1605 list_add_tail(&q->list, &pending->list);
1606 sigaddset(&pending->signal, sig);
1607 complete_signal(sig, t, group);
1608 result = TRACE_SIGNAL_DELIVERED;
1610 trace_signal_generate(sig, &q->info, t, group, result);
1611 unlock_task_sighand(t, &flags);
1617 * Let a parent know about the death of a child.
1618 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1620 * Returns true if our parent ignored us and so we've switched to
1623 bool do_notify_parent(struct task_struct *tsk, int sig)
1625 struct siginfo info;
1626 unsigned long flags;
1627 struct sighand_struct *psig;
1628 bool autoreap = false;
1629 cputime_t utime, stime;
1633 /* do_notify_parent_cldstop should have been called instead. */
1634 BUG_ON(task_is_stopped_or_traced(tsk));
1636 BUG_ON(!tsk->ptrace &&
1637 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1639 if (sig != SIGCHLD) {
1641 * This is only possible if parent == real_parent.
1642 * Check if it has changed security domain.
1644 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1648 info.si_signo = sig;
1651 * We are under tasklist_lock here so our parent is tied to
1652 * us and cannot change.
1654 * task_active_pid_ns will always return the same pid namespace
1655 * until a task passes through release_task.
1657 * write_lock() currently calls preempt_disable() which is the
1658 * same as rcu_read_lock(), but according to Oleg, this is not
1659 * correct to rely on this
1662 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1663 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1667 task_cputime(tsk, &utime, &stime);
1668 info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime);
1669 info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime);
1671 info.si_status = tsk->exit_code & 0x7f;
1672 if (tsk->exit_code & 0x80)
1673 info.si_code = CLD_DUMPED;
1674 else if (tsk->exit_code & 0x7f)
1675 info.si_code = CLD_KILLED;
1677 info.si_code = CLD_EXITED;
1678 info.si_status = tsk->exit_code >> 8;
1681 psig = tsk->parent->sighand;
1682 spin_lock_irqsave(&psig->siglock, flags);
1683 if (!tsk->ptrace && sig == SIGCHLD &&
1684 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1685 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1687 * We are exiting and our parent doesn't care. POSIX.1
1688 * defines special semantics for setting SIGCHLD to SIG_IGN
1689 * or setting the SA_NOCLDWAIT flag: we should be reaped
1690 * automatically and not left for our parent's wait4 call.
1691 * Rather than having the parent do it as a magic kind of
1692 * signal handler, we just set this to tell do_exit that we
1693 * can be cleaned up without becoming a zombie. Note that
1694 * we still call __wake_up_parent in this case, because a
1695 * blocked sys_wait4 might now return -ECHILD.
1697 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1698 * is implementation-defined: we do (if you don't want
1699 * it, just use SIG_IGN instead).
1702 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1705 if (valid_signal(sig) && sig)
1706 __group_send_sig_info(sig, &info, tsk->parent);
1707 __wake_up_parent(tsk, tsk->parent);
1708 spin_unlock_irqrestore(&psig->siglock, flags);
1714 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1715 * @tsk: task reporting the state change
1716 * @for_ptracer: the notification is for ptracer
1717 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1719 * Notify @tsk's parent that the stopped/continued state has changed. If
1720 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1721 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1724 * Must be called with tasklist_lock at least read locked.
1726 static void do_notify_parent_cldstop(struct task_struct *tsk,
1727 bool for_ptracer, int why)
1729 struct siginfo info;
1730 unsigned long flags;
1731 struct task_struct *parent;
1732 struct sighand_struct *sighand;
1733 cputime_t utime, stime;
1736 parent = tsk->parent;
1738 tsk = tsk->group_leader;
1739 parent = tsk->real_parent;
1742 info.si_signo = SIGCHLD;
1745 * see comment in do_notify_parent() about the following 4 lines
1748 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
1749 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
1752 task_cputime(tsk, &utime, &stime);
1753 info.si_utime = cputime_to_clock_t(utime);
1754 info.si_stime = cputime_to_clock_t(stime);
1759 info.si_status = SIGCONT;
1762 info.si_status = tsk->signal->group_exit_code & 0x7f;
1765 info.si_status = tsk->exit_code & 0x7f;
1771 sighand = parent->sighand;
1772 spin_lock_irqsave(&sighand->siglock, flags);
1773 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1774 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1775 __group_send_sig_info(SIGCHLD, &info, parent);
1777 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1779 __wake_up_parent(tsk, parent);
1780 spin_unlock_irqrestore(&sighand->siglock, flags);
1783 static inline int may_ptrace_stop(void)
1785 if (!likely(current->ptrace))
1788 * Are we in the middle of do_coredump?
1789 * If so and our tracer is also part of the coredump stopping
1790 * is a deadlock situation, and pointless because our tracer
1791 * is dead so don't allow us to stop.
1792 * If SIGKILL was already sent before the caller unlocked
1793 * ->siglock we must see ->core_state != NULL. Otherwise it
1794 * is safe to enter schedule().
1796 * This is almost outdated, a task with the pending SIGKILL can't
1797 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1798 * after SIGKILL was already dequeued.
1800 if (unlikely(current->mm->core_state) &&
1801 unlikely(current->mm == current->parent->mm))
1808 * Return non-zero if there is a SIGKILL that should be waking us up.
1809 * Called with the siglock held.
1811 static int sigkill_pending(struct task_struct *tsk)
1813 return sigismember(&tsk->pending.signal, SIGKILL) ||
1814 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
1818 * This must be called with current->sighand->siglock held.
1820 * This should be the path for all ptrace stops.
1821 * We always set current->last_siginfo while stopped here.
1822 * That makes it a way to test a stopped process for
1823 * being ptrace-stopped vs being job-control-stopped.
1825 * If we actually decide not to stop at all because the tracer
1826 * is gone, we keep current->exit_code unless clear_code.
1828 static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
1829 __releases(¤t->sighand->siglock)
1830 __acquires(¤t->sighand->siglock)
1832 bool gstop_done = false;
1834 if (arch_ptrace_stop_needed(exit_code, info)) {
1836 * The arch code has something special to do before a
1837 * ptrace stop. This is allowed to block, e.g. for faults
1838 * on user stack pages. We can't keep the siglock while
1839 * calling arch_ptrace_stop, so we must release it now.
1840 * To preserve proper semantics, we must do this before
1841 * any signal bookkeeping like checking group_stop_count.
1842 * Meanwhile, a SIGKILL could come in before we retake the
1843 * siglock. That must prevent us from sleeping in TASK_TRACED.
1844 * So after regaining the lock, we must check for SIGKILL.
1846 spin_unlock_irq(¤t->sighand->siglock);
1847 arch_ptrace_stop(exit_code, info);
1848 spin_lock_irq(¤t->sighand->siglock);
1849 if (sigkill_pending(current))
1854 * We're committing to trapping. TRACED should be visible before
1855 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1856 * Also, transition to TRACED and updates to ->jobctl should be
1857 * atomic with respect to siglock and should be done after the arch
1858 * hook as siglock is released and regrabbed across it.
1860 set_current_state(TASK_TRACED);
1862 current->last_siginfo = info;
1863 current->exit_code = exit_code;
1866 * If @why is CLD_STOPPED, we're trapping to participate in a group
1867 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1868 * across siglock relocks since INTERRUPT was scheduled, PENDING
1869 * could be clear now. We act as if SIGCONT is received after
1870 * TASK_TRACED is entered - ignore it.
1872 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
1873 gstop_done = task_participate_group_stop(current);
1875 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1876 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
1877 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
1878 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
1880 /* entering a trap, clear TRAPPING */
1881 task_clear_jobctl_trapping(current);
1883 spin_unlock_irq(¤t->sighand->siglock);
1884 read_lock(&tasklist_lock);
1885 if (may_ptrace_stop()) {
1887 * Notify parents of the stop.
1889 * While ptraced, there are two parents - the ptracer and
1890 * the real_parent of the group_leader. The ptracer should
1891 * know about every stop while the real parent is only
1892 * interested in the completion of group stop. The states
1893 * for the two don't interact with each other. Notify
1894 * separately unless they're gonna be duplicates.
1896 do_notify_parent_cldstop(current, true, why);
1897 if (gstop_done && ptrace_reparented(current))
1898 do_notify_parent_cldstop(current, false, why);
1901 * Don't want to allow preemption here, because
1902 * sys_ptrace() needs this task to be inactive.
1904 * XXX: implement read_unlock_no_resched().
1907 read_unlock(&tasklist_lock);
1908 preempt_enable_no_resched();
1909 freezable_schedule();
1912 * By the time we got the lock, our tracer went away.
1913 * Don't drop the lock yet, another tracer may come.
1915 * If @gstop_done, the ptracer went away between group stop
1916 * completion and here. During detach, it would have set
1917 * JOBCTL_STOP_PENDING on us and we'll re-enter
1918 * TASK_STOPPED in do_signal_stop() on return, so notifying
1919 * the real parent of the group stop completion is enough.
1922 do_notify_parent_cldstop(current, false, why);
1924 /* tasklist protects us from ptrace_freeze_traced() */
1925 __set_current_state(TASK_RUNNING);
1927 current->exit_code = 0;
1928 read_unlock(&tasklist_lock);
1932 * We are back. Now reacquire the siglock before touching
1933 * last_siginfo, so that we are sure to have synchronized with
1934 * any signal-sending on another CPU that wants to examine it.
1936 spin_lock_irq(¤t->sighand->siglock);
1937 current->last_siginfo = NULL;
1939 /* LISTENING can be set only during STOP traps, clear it */
1940 current->jobctl &= ~JOBCTL_LISTENING;
1943 * Queued signals ignored us while we were stopped for tracing.
1944 * So check for any that we should take before resuming user mode.
1945 * This sets TIF_SIGPENDING, but never clears it.
1947 recalc_sigpending_tsk(current);
1950 static void ptrace_do_notify(int signr, int exit_code, int why)
1954 memset(&info, 0, sizeof info);
1955 info.si_signo = signr;
1956 info.si_code = exit_code;
1957 info.si_pid = task_pid_vnr(current);
1958 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1960 /* Let the debugger run. */
1961 ptrace_stop(exit_code, why, 1, &info);
1964 void ptrace_notify(int exit_code)
1966 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1967 if (unlikely(current->task_works))
1970 spin_lock_irq(¤t->sighand->siglock);
1971 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
1972 spin_unlock_irq(¤t->sighand->siglock);
1976 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1977 * @signr: signr causing group stop if initiating
1979 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1980 * and participate in it. If already set, participate in the existing
1981 * group stop. If participated in a group stop (and thus slept), %true is
1982 * returned with siglock released.
1984 * If ptraced, this function doesn't handle stop itself. Instead,
1985 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1986 * untouched. The caller must ensure that INTERRUPT trap handling takes
1987 * places afterwards.
1990 * Must be called with @current->sighand->siglock held, which is released
1994 * %false if group stop is already cancelled or ptrace trap is scheduled.
1995 * %true if participated in group stop.
1997 static bool do_signal_stop(int signr)
1998 __releases(¤t->sighand->siglock)
2000 struct signal_struct *sig = current->signal;
2002 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2003 unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2004 struct task_struct *t;
2006 /* signr will be recorded in task->jobctl for retries */
2007 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2009 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2010 unlikely(signal_group_exit(sig)))
2013 * There is no group stop already in progress. We must
2016 * While ptraced, a task may be resumed while group stop is
2017 * still in effect and then receive a stop signal and
2018 * initiate another group stop. This deviates from the
2019 * usual behavior as two consecutive stop signals can't
2020 * cause two group stops when !ptraced. That is why we
2021 * also check !task_is_stopped(t) below.
2023 * The condition can be distinguished by testing whether
2024 * SIGNAL_STOP_STOPPED is already set. Don't generate
2025 * group_exit_code in such case.
2027 * This is not necessary for SIGNAL_STOP_CONTINUED because
2028 * an intervening stop signal is required to cause two
2029 * continued events regardless of ptrace.
2031 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2032 sig->group_exit_code = signr;
2034 sig->group_stop_count = 0;
2036 if (task_set_jobctl_pending(current, signr | gstop))
2037 sig->group_stop_count++;
2040 while_each_thread(current, t) {
2042 * Setting state to TASK_STOPPED for a group
2043 * stop is always done with the siglock held,
2044 * so this check has no races.
2046 if (!task_is_stopped(t) &&
2047 task_set_jobctl_pending(t, signr | gstop)) {
2048 sig->group_stop_count++;
2049 if (likely(!(t->ptrace & PT_SEIZED)))
2050 signal_wake_up(t, 0);
2052 ptrace_trap_notify(t);
2057 if (likely(!current->ptrace)) {
2061 * If there are no other threads in the group, or if there
2062 * is a group stop in progress and we are the last to stop,
2063 * report to the parent.
2065 if (task_participate_group_stop(current))
2066 notify = CLD_STOPPED;
2068 __set_current_state(TASK_STOPPED);
2069 spin_unlock_irq(¤t->sighand->siglock);
2072 * Notify the parent of the group stop completion. Because
2073 * we're not holding either the siglock or tasklist_lock
2074 * here, ptracer may attach inbetween; however, this is for
2075 * group stop and should always be delivered to the real
2076 * parent of the group leader. The new ptracer will get
2077 * its notification when this task transitions into
2081 read_lock(&tasklist_lock);
2082 do_notify_parent_cldstop(current, false, notify);
2083 read_unlock(&tasklist_lock);
2086 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2087 freezable_schedule();
2091 * While ptraced, group stop is handled by STOP trap.
2092 * Schedule it and let the caller deal with it.
2094 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2100 * do_jobctl_trap - take care of ptrace jobctl traps
2102 * When PT_SEIZED, it's used for both group stop and explicit
2103 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2104 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2105 * the stop signal; otherwise, %SIGTRAP.
2107 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2108 * number as exit_code and no siginfo.
2111 * Must be called with @current->sighand->siglock held, which may be
2112 * released and re-acquired before returning with intervening sleep.
2114 static void do_jobctl_trap(void)
2116 struct signal_struct *signal = current->signal;
2117 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2119 if (current->ptrace & PT_SEIZED) {
2120 if (!signal->group_stop_count &&
2121 !(signal->flags & SIGNAL_STOP_STOPPED))
2123 WARN_ON_ONCE(!signr);
2124 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2127 WARN_ON_ONCE(!signr);
2128 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2129 current->exit_code = 0;
2133 static int ptrace_signal(int signr, siginfo_t *info)
2135 ptrace_signal_deliver();
2137 * We do not check sig_kernel_stop(signr) but set this marker
2138 * unconditionally because we do not know whether debugger will
2139 * change signr. This flag has no meaning unless we are going
2140 * to stop after return from ptrace_stop(). In this case it will
2141 * be checked in do_signal_stop(), we should only stop if it was
2142 * not cleared by SIGCONT while we were sleeping. See also the
2143 * comment in dequeue_signal().
2145 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2146 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2148 /* We're back. Did the debugger cancel the sig? */
2149 signr = current->exit_code;
2153 current->exit_code = 0;
2156 * Update the siginfo structure if the signal has
2157 * changed. If the debugger wanted something
2158 * specific in the siginfo structure then it should
2159 * have updated *info via PTRACE_SETSIGINFO.
2161 if (signr != info->si_signo) {
2162 info->si_signo = signr;
2164 info->si_code = SI_USER;
2166 info->si_pid = task_pid_vnr(current->parent);
2167 info->si_uid = from_kuid_munged(current_user_ns(),
2168 task_uid(current->parent));
2172 /* If the (new) signal is now blocked, requeue it. */
2173 if (sigismember(¤t->blocked, signr)) {
2174 specific_send_sig_info(signr, info, current);
2181 int get_signal(struct ksignal *ksig)
2183 struct sighand_struct *sighand = current->sighand;
2184 struct signal_struct *signal = current->signal;
2187 if (unlikely(current->task_works))
2190 if (unlikely(uprobe_deny_signal()))
2194 * Do this once, we can't return to user-mode if freezing() == T.
2195 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2196 * thus do not need another check after return.
2201 spin_lock_irq(&sighand->siglock);
2203 * Every stopped thread goes here after wakeup. Check to see if
2204 * we should notify the parent, prepare_signal(SIGCONT) encodes
2205 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2207 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2210 if (signal->flags & SIGNAL_CLD_CONTINUED)
2211 why = CLD_CONTINUED;
2215 signal->flags &= ~SIGNAL_CLD_MASK;
2217 spin_unlock_irq(&sighand->siglock);
2220 * Notify the parent that we're continuing. This event is
2221 * always per-process and doesn't make whole lot of sense
2222 * for ptracers, who shouldn't consume the state via
2223 * wait(2) either, but, for backward compatibility, notify
2224 * the ptracer of the group leader too unless it's gonna be
2227 read_lock(&tasklist_lock);
2228 do_notify_parent_cldstop(current, false, why);
2230 if (ptrace_reparented(current->group_leader))
2231 do_notify_parent_cldstop(current->group_leader,
2233 read_unlock(&tasklist_lock);
2239 struct k_sigaction *ka;
2241 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2245 if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
2247 spin_unlock_irq(&sighand->siglock);
2251 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2254 break; /* will return 0 */
2256 if (unlikely(current->ptrace) && signr != SIGKILL) {
2257 signr = ptrace_signal(signr, &ksig->info);
2262 ka = &sighand->action[signr-1];
2264 /* Trace actually delivered signals. */
2265 trace_signal_deliver(signr, &ksig->info, ka);
2267 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2269 if (ka->sa.sa_handler != SIG_DFL) {
2270 /* Run the handler. */
2273 if (ka->sa.sa_flags & SA_ONESHOT)
2274 ka->sa.sa_handler = SIG_DFL;
2276 break; /* will return non-zero "signr" value */
2280 * Now we are doing the default action for this signal.
2282 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2286 * Global init gets no signals it doesn't want.
2287 * Container-init gets no signals it doesn't want from same
2290 * Note that if global/container-init sees a sig_kernel_only()
2291 * signal here, the signal must have been generated internally
2292 * or must have come from an ancestor namespace. In either
2293 * case, the signal cannot be dropped.
2295 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2296 !sig_kernel_only(signr))
2299 if (sig_kernel_stop(signr)) {
2301 * The default action is to stop all threads in
2302 * the thread group. The job control signals
2303 * do nothing in an orphaned pgrp, but SIGSTOP
2304 * always works. Note that siglock needs to be
2305 * dropped during the call to is_orphaned_pgrp()
2306 * because of lock ordering with tasklist_lock.
2307 * This allows an intervening SIGCONT to be posted.
2308 * We need to check for that and bail out if necessary.
2310 if (signr != SIGSTOP) {
2311 spin_unlock_irq(&sighand->siglock);
2313 /* signals can be posted during this window */
2315 if (is_current_pgrp_orphaned())
2318 spin_lock_irq(&sighand->siglock);
2321 if (likely(do_signal_stop(ksig->info.si_signo))) {
2322 /* It released the siglock. */
2327 * We didn't actually stop, due to a race
2328 * with SIGCONT or something like that.
2333 spin_unlock_irq(&sighand->siglock);
2336 * Anything else is fatal, maybe with a core dump.
2338 current->flags |= PF_SIGNALED;
2340 if (sig_kernel_coredump(signr)) {
2341 if (print_fatal_signals)
2342 print_fatal_signal(ksig->info.si_signo);
2343 proc_coredump_connector(current);
2345 * If it was able to dump core, this kills all
2346 * other threads in the group and synchronizes with
2347 * their demise. If we lost the race with another
2348 * thread getting here, it set group_exit_code
2349 * first and our do_group_exit call below will use
2350 * that value and ignore the one we pass it.
2352 do_coredump(&ksig->info);
2356 * Death signals, no core dump.
2358 do_group_exit(ksig->info.si_signo);
2361 spin_unlock_irq(&sighand->siglock);
2364 return ksig->sig > 0;
2368 * signal_delivered -
2369 * @ksig: kernel signal struct
2370 * @stepping: nonzero if debugger single-step or block-step in use
2372 * This function should be called when a signal has successfully been
2373 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2374 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2375 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2377 static void signal_delivered(struct ksignal *ksig, int stepping)
2381 /* A signal was successfully delivered, and the
2382 saved sigmask was stored on the signal frame,
2383 and will be restored by sigreturn. So we can
2384 simply clear the restore sigmask flag. */
2385 clear_restore_sigmask();
2387 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2388 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2389 sigaddset(&blocked, ksig->sig);
2390 set_current_blocked(&blocked);
2391 tracehook_signal_handler(stepping);
2394 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2397 force_sigsegv(ksig->sig, current);
2399 signal_delivered(ksig, stepping);
2403 * It could be that complete_signal() picked us to notify about the
2404 * group-wide signal. Other threads should be notified now to take
2405 * the shared signals in @which since we will not.
2407 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2410 struct task_struct *t;
2412 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2413 if (sigisemptyset(&retarget))
2417 while_each_thread(tsk, t) {
2418 if (t->flags & PF_EXITING)
2421 if (!has_pending_signals(&retarget, &t->blocked))
2423 /* Remove the signals this thread can handle. */
2424 sigandsets(&retarget, &retarget, &t->blocked);
2426 if (!signal_pending(t))
2427 signal_wake_up(t, 0);
2429 if (sigisemptyset(&retarget))
2434 void exit_signals(struct task_struct *tsk)
2440 * @tsk is about to have PF_EXITING set - lock out users which
2441 * expect stable threadgroup.
2443 threadgroup_change_begin(tsk);
2445 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2446 tsk->flags |= PF_EXITING;
2447 threadgroup_change_end(tsk);
2451 spin_lock_irq(&tsk->sighand->siglock);
2453 * From now this task is not visible for group-wide signals,
2454 * see wants_signal(), do_signal_stop().
2456 tsk->flags |= PF_EXITING;
2458 threadgroup_change_end(tsk);
2460 if (!signal_pending(tsk))
2463 unblocked = tsk->blocked;
2464 signotset(&unblocked);
2465 retarget_shared_pending(tsk, &unblocked);
2467 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2468 task_participate_group_stop(tsk))
2469 group_stop = CLD_STOPPED;
2471 spin_unlock_irq(&tsk->sighand->siglock);
2474 * If group stop has completed, deliver the notification. This
2475 * should always go to the real parent of the group leader.
2477 if (unlikely(group_stop)) {
2478 read_lock(&tasklist_lock);
2479 do_notify_parent_cldstop(tsk, false, group_stop);
2480 read_unlock(&tasklist_lock);
2484 EXPORT_SYMBOL(recalc_sigpending);
2485 EXPORT_SYMBOL_GPL(dequeue_signal);
2486 EXPORT_SYMBOL(flush_signals);
2487 EXPORT_SYMBOL(force_sig);
2488 EXPORT_SYMBOL(send_sig);
2489 EXPORT_SYMBOL(send_sig_info);
2490 EXPORT_SYMBOL(sigprocmask);
2491 EXPORT_SYMBOL(block_all_signals);
2492 EXPORT_SYMBOL(unblock_all_signals);
2496 * System call entry points.
2500 * sys_restart_syscall - restart a system call
2502 SYSCALL_DEFINE0(restart_syscall)
2504 struct restart_block *restart = ¤t_thread_info()->restart_block;
2505 return restart->fn(restart);
2508 long do_no_restart_syscall(struct restart_block *param)
2513 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2515 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2516 sigset_t newblocked;
2517 /* A set of now blocked but previously unblocked signals. */
2518 sigandnsets(&newblocked, newset, ¤t->blocked);
2519 retarget_shared_pending(tsk, &newblocked);
2521 tsk->blocked = *newset;
2522 recalc_sigpending();
2526 * set_current_blocked - change current->blocked mask
2529 * It is wrong to change ->blocked directly, this helper should be used
2530 * to ensure the process can't miss a shared signal we are going to block.
2532 void set_current_blocked(sigset_t *newset)
2534 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2535 __set_current_blocked(newset);
2538 void __set_current_blocked(const sigset_t *newset)
2540 struct task_struct *tsk = current;
2542 spin_lock_irq(&tsk->sighand->siglock);
2543 __set_task_blocked(tsk, newset);
2544 spin_unlock_irq(&tsk->sighand->siglock);
2548 * This is also useful for kernel threads that want to temporarily
2549 * (or permanently) block certain signals.
2551 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2552 * interface happily blocks "unblockable" signals like SIGKILL
2555 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2557 struct task_struct *tsk = current;
2560 /* Lockless, only current can change ->blocked, never from irq */
2562 *oldset = tsk->blocked;
2566 sigorsets(&newset, &tsk->blocked, set);
2569 sigandnsets(&newset, &tsk->blocked, set);
2578 __set_current_blocked(&newset);
2583 * sys_rt_sigprocmask - change the list of currently blocked signals
2584 * @how: whether to add, remove, or set signals
2585 * @nset: stores pending signals
2586 * @oset: previous value of signal mask if non-null
2587 * @sigsetsize: size of sigset_t type
2589 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2590 sigset_t __user *, oset, size_t, sigsetsize)
2592 sigset_t old_set, new_set;
2595 /* XXX: Don't preclude handling different sized sigset_t's. */
2596 if (sigsetsize != sizeof(sigset_t))
2599 old_set = current->blocked;
2602 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2604 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2606 error = sigprocmask(how, &new_set, NULL);
2612 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2619 #ifdef CONFIG_COMPAT
2620 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2621 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2624 sigset_t old_set = current->blocked;
2626 /* XXX: Don't preclude handling different sized sigset_t's. */
2627 if (sigsetsize != sizeof(sigset_t))
2631 compat_sigset_t new32;
2634 if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
2637 sigset_from_compat(&new_set, &new32);
2638 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2640 error = sigprocmask(how, &new_set, NULL);
2645 compat_sigset_t old32;
2646 sigset_to_compat(&old32, &old_set);
2647 if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
2652 return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
2653 (sigset_t __user *)oset, sigsetsize);
2658 static int do_sigpending(void *set, unsigned long sigsetsize)
2660 if (sigsetsize > sizeof(sigset_t))
2663 spin_lock_irq(¤t->sighand->siglock);
2664 sigorsets(set, ¤t->pending.signal,
2665 ¤t->signal->shared_pending.signal);
2666 spin_unlock_irq(¤t->sighand->siglock);
2668 /* Outside the lock because only this thread touches it. */
2669 sigandsets(set, ¤t->blocked, set);
2674 * sys_rt_sigpending - examine a pending signal that has been raised
2676 * @uset: stores pending signals
2677 * @sigsetsize: size of sigset_t type or larger
2679 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
2682 int err = do_sigpending(&set, sigsetsize);
2683 if (!err && copy_to_user(uset, &set, sigsetsize))
2688 #ifdef CONFIG_COMPAT
2689 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
2690 compat_size_t, sigsetsize)
2694 int err = do_sigpending(&set, sigsetsize);
2696 compat_sigset_t set32;
2697 sigset_to_compat(&set32, &set);
2698 /* we can get here only if sigsetsize <= sizeof(set) */
2699 if (copy_to_user(uset, &set32, sigsetsize))
2704 return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
2709 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2711 int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
2715 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2717 if (from->si_code < 0)
2718 return __copy_to_user(to, from, sizeof(siginfo_t))
2721 * If you change siginfo_t structure, please be sure
2722 * this code is fixed accordingly.
2723 * Please remember to update the signalfd_copyinfo() function
2724 * inside fs/signalfd.c too, in case siginfo_t changes.
2725 * It should never copy any pad contained in the structure
2726 * to avoid security leaks, but must copy the generic
2727 * 3 ints plus the relevant union member.
2729 err = __put_user(from->si_signo, &to->si_signo);
2730 err |= __put_user(from->si_errno, &to->si_errno);
2731 err |= __put_user((short)from->si_code, &to->si_code);
2732 switch (from->si_code & __SI_MASK) {
2734 err |= __put_user(from->si_pid, &to->si_pid);
2735 err |= __put_user(from->si_uid, &to->si_uid);
2738 err |= __put_user(from->si_tid, &to->si_tid);
2739 err |= __put_user(from->si_overrun, &to->si_overrun);
2740 err |= __put_user(from->si_ptr, &to->si_ptr);
2743 err |= __put_user(from->si_band, &to->si_band);
2744 err |= __put_user(from->si_fd, &to->si_fd);
2747 err |= __put_user(from->si_addr, &to->si_addr);
2748 #ifdef __ARCH_SI_TRAPNO
2749 err |= __put_user(from->si_trapno, &to->si_trapno);
2751 #ifdef BUS_MCEERR_AO
2753 * Other callers might not initialize the si_lsb field,
2754 * so check explicitly for the right codes here.
2756 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
2757 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2760 err |= __put_user(from->si_lower, &to->si_lower);
2761 err |= __put_user(from->si_upper, &to->si_upper);
2765 err |= __put_user(from->si_pid, &to->si_pid);
2766 err |= __put_user(from->si_uid, &to->si_uid);
2767 err |= __put_user(from->si_status, &to->si_status);
2768 err |= __put_user(from->si_utime, &to->si_utime);
2769 err |= __put_user(from->si_stime, &to->si_stime);
2771 case __SI_RT: /* This is not generated by the kernel as of now. */
2772 case __SI_MESGQ: /* But this is */
2773 err |= __put_user(from->si_pid, &to->si_pid);
2774 err |= __put_user(from->si_uid, &to->si_uid);
2775 err |= __put_user(from->si_ptr, &to->si_ptr);
2777 #ifdef __ARCH_SIGSYS
2779 err |= __put_user(from->si_call_addr, &to->si_call_addr);
2780 err |= __put_user(from->si_syscall, &to->si_syscall);
2781 err |= __put_user(from->si_arch, &to->si_arch);
2784 default: /* this is just in case for now ... */
2785 err |= __put_user(from->si_pid, &to->si_pid);
2786 err |= __put_user(from->si_uid, &to->si_uid);
2795 * do_sigtimedwait - wait for queued signals specified in @which
2796 * @which: queued signals to wait for
2797 * @info: if non-null, the signal's siginfo is returned here
2798 * @ts: upper bound on process time suspension
2800 int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
2801 const struct timespec *ts)
2803 struct task_struct *tsk = current;
2804 long timeout = MAX_SCHEDULE_TIMEOUT;
2805 sigset_t mask = *which;
2809 if (!timespec_valid(ts))
2811 timeout = timespec_to_jiffies(ts);
2813 * We can be close to the next tick, add another one
2814 * to ensure we will wait at least the time asked for.
2816 if (ts->tv_sec || ts->tv_nsec)
2821 * Invert the set of allowed signals to get those we want to block.
2823 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
2826 spin_lock_irq(&tsk->sighand->siglock);
2827 sig = dequeue_signal(tsk, &mask, info);
2828 if (!sig && timeout) {
2830 * None ready, temporarily unblock those we're interested
2831 * while we are sleeping in so that we'll be awakened when
2832 * they arrive. Unblocking is always fine, we can avoid
2833 * set_current_blocked().
2835 tsk->real_blocked = tsk->blocked;
2836 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
2837 recalc_sigpending();
2838 spin_unlock_irq(&tsk->sighand->siglock);
2840 timeout = freezable_schedule_timeout_interruptible(timeout);
2842 spin_lock_irq(&tsk->sighand->siglock);
2843 __set_task_blocked(tsk, &tsk->real_blocked);
2844 sigemptyset(&tsk->real_blocked);
2845 sig = dequeue_signal(tsk, &mask, info);
2847 spin_unlock_irq(&tsk->sighand->siglock);
2851 return timeout ? -EINTR : -EAGAIN;
2855 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2857 * @uthese: queued signals to wait for
2858 * @uinfo: if non-null, the signal's siginfo is returned here
2859 * @uts: upper bound on process time suspension
2860 * @sigsetsize: size of sigset_t type
2862 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2863 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2871 /* XXX: Don't preclude handling different sized sigset_t's. */
2872 if (sigsetsize != sizeof(sigset_t))
2875 if (copy_from_user(&these, uthese, sizeof(these)))
2879 if (copy_from_user(&ts, uts, sizeof(ts)))
2883 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
2885 if (ret > 0 && uinfo) {
2886 if (copy_siginfo_to_user(uinfo, &info))
2894 * sys_kill - send a signal to a process
2895 * @pid: the PID of the process
2896 * @sig: signal to be sent
2898 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2900 struct siginfo info;
2902 info.si_signo = sig;
2904 info.si_code = SI_USER;
2905 info.si_pid = task_tgid_vnr(current);
2906 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2908 return kill_something_info(sig, &info, pid);
2912 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2914 struct task_struct *p;
2918 p = find_task_by_vpid(pid);
2919 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2920 error = check_kill_permission(sig, info, p);
2922 * The null signal is a permissions and process existence
2923 * probe. No signal is actually delivered.
2925 if (!error && sig) {
2926 error = do_send_sig_info(sig, info, p, false);
2928 * If lock_task_sighand() failed we pretend the task
2929 * dies after receiving the signal. The window is tiny,
2930 * and the signal is private anyway.
2932 if (unlikely(error == -ESRCH))
2941 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2943 struct siginfo info = {};
2945 info.si_signo = sig;
2947 info.si_code = SI_TKILL;
2948 info.si_pid = task_tgid_vnr(current);
2949 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2951 return do_send_specific(tgid, pid, sig, &info);
2955 * sys_tgkill - send signal to one specific thread
2956 * @tgid: the thread group ID of the thread
2957 * @pid: the PID of the thread
2958 * @sig: signal to be sent
2960 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2961 * exists but it's not belonging to the target process anymore. This
2962 * method solves the problem of threads exiting and PIDs getting reused.
2964 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2966 /* This is only valid for single tasks */
2967 if (pid <= 0 || tgid <= 0)
2970 return do_tkill(tgid, pid, sig);
2974 * sys_tkill - send signal to one specific task
2975 * @pid: the PID of the task
2976 * @sig: signal to be sent
2978 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2980 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
2982 /* This is only valid for single tasks */
2986 return do_tkill(0, pid, sig);
2989 static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
2991 /* Not even root can pretend to send signals from the kernel.
2992 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2994 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
2995 (task_pid_vnr(current) != pid)) {
2996 /* We used to allow any < 0 si_code */
2997 WARN_ON_ONCE(info->si_code < 0);
3000 info->si_signo = sig;
3002 /* POSIX.1b doesn't mention process groups. */
3003 return kill_proc_info(sig, info, pid);
3007 * sys_rt_sigqueueinfo - send signal information to a signal
3008 * @pid: the PID of the thread
3009 * @sig: signal to be sent
3010 * @uinfo: signal info to be sent
3012 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3013 siginfo_t __user *, uinfo)
3016 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3018 return do_rt_sigqueueinfo(pid, sig, &info);
3021 #ifdef CONFIG_COMPAT
3022 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3025 struct compat_siginfo __user *, uinfo)
3028 int ret = copy_siginfo_from_user32(&info, uinfo);
3031 return do_rt_sigqueueinfo(pid, sig, &info);
3035 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
3037 /* This is only valid for single tasks */
3038 if (pid <= 0 || tgid <= 0)
3041 /* Not even root can pretend to send signals from the kernel.
3042 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3044 if (((info->si_code >= 0 || info->si_code == SI_TKILL)) &&
3045 (task_pid_vnr(current) != pid)) {
3046 /* We used to allow any < 0 si_code */
3047 WARN_ON_ONCE(info->si_code < 0);
3050 info->si_signo = sig;
3052 return do_send_specific(tgid, pid, sig, info);
3055 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3056 siginfo_t __user *, uinfo)
3060 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3063 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3066 #ifdef CONFIG_COMPAT
3067 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3071 struct compat_siginfo __user *, uinfo)
3075 if (copy_siginfo_from_user32(&info, uinfo))
3077 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3082 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3084 void kernel_sigaction(int sig, __sighandler_t action)
3086 spin_lock_irq(¤t->sighand->siglock);
3087 current->sighand->action[sig - 1].sa.sa_handler = action;
3088 if (action == SIG_IGN) {
3092 sigaddset(&mask, sig);
3094 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3095 flush_sigqueue_mask(&mask, ¤t->pending);
3096 recalc_sigpending();
3098 spin_unlock_irq(¤t->sighand->siglock);
3100 EXPORT_SYMBOL(kernel_sigaction);
3102 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3104 struct task_struct *p = current, *t;
3105 struct k_sigaction *k;
3108 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3111 k = &p->sighand->action[sig-1];
3113 spin_lock_irq(&p->sighand->siglock);
3118 sigdelsetmask(&act->sa.sa_mask,
3119 sigmask(SIGKILL) | sigmask(SIGSTOP));
3123 * "Setting a signal action to SIG_IGN for a signal that is
3124 * pending shall cause the pending signal to be discarded,
3125 * whether or not it is blocked."
3127 * "Setting a signal action to SIG_DFL for a signal that is
3128 * pending and whose default action is to ignore the signal
3129 * (for example, SIGCHLD), shall cause the pending signal to
3130 * be discarded, whether or not it is blocked"
3132 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3134 sigaddset(&mask, sig);
3135 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3136 for_each_thread(p, t)
3137 flush_sigqueue_mask(&mask, &t->pending);
3141 spin_unlock_irq(&p->sighand->siglock);
3146 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
3151 oss.ss_sp = (void __user *) current->sas_ss_sp;
3152 oss.ss_size = current->sas_ss_size;
3153 oss.ss_flags = sas_ss_flags(sp);
3161 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
3163 error = __get_user(ss_sp, &uss->ss_sp) |
3164 __get_user(ss_flags, &uss->ss_flags) |
3165 __get_user(ss_size, &uss->ss_size);
3170 if (on_sig_stack(sp))
3175 * Note - this code used to test ss_flags incorrectly:
3176 * old code may have been written using ss_flags==0
3177 * to mean ss_flags==SS_ONSTACK (as this was the only
3178 * way that worked) - this fix preserves that older
3181 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
3184 if (ss_flags == SS_DISABLE) {
3189 if (ss_size < MINSIGSTKSZ)
3193 current->sas_ss_sp = (unsigned long) ss_sp;
3194 current->sas_ss_size = ss_size;
3200 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
3202 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
3203 __put_user(oss.ss_size, &uoss->ss_size) |
3204 __put_user(oss.ss_flags, &uoss->ss_flags);
3210 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3212 return do_sigaltstack(uss, uoss, current_user_stack_pointer());
3215 int restore_altstack(const stack_t __user *uss)
3217 int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
3218 /* squash all but EFAULT for now */
3219 return err == -EFAULT ? err : 0;
3222 int __save_altstack(stack_t __user *uss, unsigned long sp)
3224 struct task_struct *t = current;
3225 return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3226 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3227 __put_user(t->sas_ss_size, &uss->ss_size);
3230 #ifdef CONFIG_COMPAT
3231 COMPAT_SYSCALL_DEFINE2(sigaltstack,
3232 const compat_stack_t __user *, uss_ptr,
3233 compat_stack_t __user *, uoss_ptr)
3240 compat_stack_t uss32;
3242 memset(&uss, 0, sizeof(stack_t));
3243 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
3245 uss.ss_sp = compat_ptr(uss32.ss_sp);
3246 uss.ss_flags = uss32.ss_flags;
3247 uss.ss_size = uss32.ss_size;
3251 ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
3252 (stack_t __force __user *) &uoss,
3253 compat_user_stack_pointer());
3255 if (ret >= 0 && uoss_ptr) {
3256 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
3257 __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
3258 __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
3259 __put_user(uoss.ss_size, &uoss_ptr->ss_size))
3265 int compat_restore_altstack(const compat_stack_t __user *uss)
3267 int err = compat_sys_sigaltstack(uss, NULL);
3268 /* squash all but -EFAULT for now */
3269 return err == -EFAULT ? err : 0;
3272 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
3274 struct task_struct *t = current;
3275 return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
3276 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3277 __put_user(t->sas_ss_size, &uss->ss_size);
3281 #ifdef __ARCH_WANT_SYS_SIGPENDING
3284 * sys_sigpending - examine pending signals
3285 * @set: where mask of pending signal is returned
3287 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
3289 return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
3294 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3296 * sys_sigprocmask - examine and change blocked signals
3297 * @how: whether to add, remove, or set signals
3298 * @nset: signals to add or remove (if non-null)
3299 * @oset: previous value of signal mask if non-null
3301 * Some platforms have their own version with special arguments;
3302 * others support only sys_rt_sigprocmask.
3305 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
3306 old_sigset_t __user *, oset)
3308 old_sigset_t old_set, new_set;
3309 sigset_t new_blocked;
3311 old_set = current->blocked.sig[0];
3314 if (copy_from_user(&new_set, nset, sizeof(*nset)))
3317 new_blocked = current->blocked;
3321 sigaddsetmask(&new_blocked, new_set);
3324 sigdelsetmask(&new_blocked, new_set);
3327 new_blocked.sig[0] = new_set;
3333 set_current_blocked(&new_blocked);
3337 if (copy_to_user(oset, &old_set, sizeof(*oset)))
3343 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3345 #ifndef CONFIG_ODD_RT_SIGACTION
3347 * sys_rt_sigaction - alter an action taken by a process
3348 * @sig: signal to be sent
3349 * @act: new sigaction
3350 * @oact: used to save the previous sigaction
3351 * @sigsetsize: size of sigset_t type
3353 SYSCALL_DEFINE4(rt_sigaction, int, sig,
3354 const struct sigaction __user *, act,
3355 struct sigaction __user *, oact,
3358 struct k_sigaction new_sa, old_sa;
3361 /* XXX: Don't preclude handling different sized sigset_t's. */
3362 if (sigsetsize != sizeof(sigset_t))
3366 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
3370 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
3373 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
3379 #ifdef CONFIG_COMPAT
3380 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
3381 const struct compat_sigaction __user *, act,
3382 struct compat_sigaction __user *, oact,
3383 compat_size_t, sigsetsize)
3385 struct k_sigaction new_ka, old_ka;
3386 compat_sigset_t mask;
3387 #ifdef __ARCH_HAS_SA_RESTORER
3388 compat_uptr_t restorer;
3392 /* XXX: Don't preclude handling different sized sigset_t's. */
3393 if (sigsetsize != sizeof(compat_sigset_t))
3397 compat_uptr_t handler;
3398 ret = get_user(handler, &act->sa_handler);
3399 new_ka.sa.sa_handler = compat_ptr(handler);
3400 #ifdef __ARCH_HAS_SA_RESTORER
3401 ret |= get_user(restorer, &act->sa_restorer);
3402 new_ka.sa.sa_restorer = compat_ptr(restorer);
3404 ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
3405 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
3408 sigset_from_compat(&new_ka.sa.sa_mask, &mask);
3411 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3413 sigset_to_compat(&mask, &old_ka.sa.sa_mask);
3414 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
3416 ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
3417 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
3418 #ifdef __ARCH_HAS_SA_RESTORER
3419 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3420 &oact->sa_restorer);
3426 #endif /* !CONFIG_ODD_RT_SIGACTION */
3428 #ifdef CONFIG_OLD_SIGACTION
3429 SYSCALL_DEFINE3(sigaction, int, sig,
3430 const struct old_sigaction __user *, act,
3431 struct old_sigaction __user *, oact)
3433 struct k_sigaction new_ka, old_ka;
3438 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3439 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
3440 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
3441 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3442 __get_user(mask, &act->sa_mask))
3444 #ifdef __ARCH_HAS_KA_RESTORER
3445 new_ka.ka_restorer = NULL;
3447 siginitset(&new_ka.sa.sa_mask, mask);
3450 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3453 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3454 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
3455 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
3456 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3457 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3464 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3465 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
3466 const struct compat_old_sigaction __user *, act,
3467 struct compat_old_sigaction __user *, oact)
3469 struct k_sigaction new_ka, old_ka;
3471 compat_old_sigset_t mask;
3472 compat_uptr_t handler, restorer;
3475 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3476 __get_user(handler, &act->sa_handler) ||
3477 __get_user(restorer, &act->sa_restorer) ||
3478 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3479 __get_user(mask, &act->sa_mask))
3482 #ifdef __ARCH_HAS_KA_RESTORER
3483 new_ka.ka_restorer = NULL;
3485 new_ka.sa.sa_handler = compat_ptr(handler);
3486 new_ka.sa.sa_restorer = compat_ptr(restorer);
3487 siginitset(&new_ka.sa.sa_mask, mask);
3490 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3493 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3494 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
3495 &oact->sa_handler) ||
3496 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3497 &oact->sa_restorer) ||
3498 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3499 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3506 #ifdef CONFIG_SGETMASK_SYSCALL
3509 * For backwards compatibility. Functionality superseded by sigprocmask.
3511 SYSCALL_DEFINE0(sgetmask)
3514 return current->blocked.sig[0];
3517 SYSCALL_DEFINE1(ssetmask, int, newmask)
3519 int old = current->blocked.sig[0];
3522 siginitset(&newset, newmask);
3523 set_current_blocked(&newset);
3527 #endif /* CONFIG_SGETMASK_SYSCALL */
3529 #ifdef __ARCH_WANT_SYS_SIGNAL
3531 * For backwards compatibility. Functionality superseded by sigaction.
3533 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
3535 struct k_sigaction new_sa, old_sa;
3538 new_sa.sa.sa_handler = handler;
3539 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
3540 sigemptyset(&new_sa.sa.sa_mask);
3542 ret = do_sigaction(sig, &new_sa, &old_sa);
3544 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
3546 #endif /* __ARCH_WANT_SYS_SIGNAL */
3548 #ifdef __ARCH_WANT_SYS_PAUSE
3550 SYSCALL_DEFINE0(pause)
3552 while (!signal_pending(current)) {
3553 current->state = TASK_INTERRUPTIBLE;
3556 return -ERESTARTNOHAND;
3561 int sigsuspend(sigset_t *set)
3563 current->saved_sigmask = current->blocked;
3564 set_current_blocked(set);
3566 current->state = TASK_INTERRUPTIBLE;
3568 set_restore_sigmask();
3569 return -ERESTARTNOHAND;
3573 * sys_rt_sigsuspend - replace the signal mask for a value with the
3574 * @unewset value until a signal is received
3575 * @unewset: new signal mask value
3576 * @sigsetsize: size of sigset_t type
3578 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
3582 /* XXX: Don't preclude handling different sized sigset_t's. */
3583 if (sigsetsize != sizeof(sigset_t))
3586 if (copy_from_user(&newset, unewset, sizeof(newset)))
3588 return sigsuspend(&newset);
3591 #ifdef CONFIG_COMPAT
3592 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
3596 compat_sigset_t newset32;
3598 /* XXX: Don't preclude handling different sized sigset_t's. */
3599 if (sigsetsize != sizeof(sigset_t))
3602 if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
3604 sigset_from_compat(&newset, &newset32);
3605 return sigsuspend(&newset);
3607 /* on little-endian bitmaps don't care about granularity */
3608 return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize);
3613 #ifdef CONFIG_OLD_SIGSUSPEND
3614 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
3617 siginitset(&blocked, mask);
3618 return sigsuspend(&blocked);
3621 #ifdef CONFIG_OLD_SIGSUSPEND3
3622 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
3625 siginitset(&blocked, mask);
3626 return sigsuspend(&blocked);
3630 __weak const char *arch_vma_name(struct vm_area_struct *vma)
3635 void __init signals_init(void)
3637 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
3640 #ifdef CONFIG_KGDB_KDB
3641 #include <linux/kdb.h>
3643 * kdb_send_sig_info - Allows kdb to send signals without exposing
3644 * signal internals. This function checks if the required locks are
3645 * available before calling the main signal code, to avoid kdb
3649 kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
3651 static struct task_struct *kdb_prev_t;
3653 if (!spin_trylock(&t->sighand->siglock)) {
3654 kdb_printf("Can't do kill command now.\n"
3655 "The sigmask lock is held somewhere else in "
3656 "kernel, try again later\n");
3659 spin_unlock(&t->sighand->siglock);
3660 new_t = kdb_prev_t != t;
3662 if (t->state != TASK_RUNNING && new_t) {
3663 kdb_printf("Process is not RUNNING, sending a signal from "
3664 "kdb risks deadlock\n"
3665 "on the run queue locks. "
3666 "The signal has _not_ been sent.\n"
3667 "Reissue the kill command if you want to risk "
3671 sig = info->si_signo;
3672 if (send_sig_info(sig, info, t))
3673 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3676 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
3678 #endif /* CONFIG_KGDB_KDB */