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 long 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 long 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 this kthread.
419 void flush_signals(struct task_struct *t)
423 spin_lock_irqsave(&t->sighand->siglock, flags);
424 clear_tsk_thread_flag(t, TIF_SIGPENDING);
425 flush_sigqueue(&t->pending);
426 flush_sigqueue(&t->signal->shared_pending);
427 spin_unlock_irqrestore(&t->sighand->siglock, flags);
430 static void __flush_itimer_signals(struct sigpending *pending)
432 sigset_t signal, retain;
433 struct sigqueue *q, *n;
435 signal = pending->signal;
436 sigemptyset(&retain);
438 list_for_each_entry_safe(q, n, &pending->list, list) {
439 int sig = q->info.si_signo;
441 if (likely(q->info.si_code != SI_TIMER)) {
442 sigaddset(&retain, sig);
444 sigdelset(&signal, sig);
445 list_del_init(&q->list);
450 sigorsets(&pending->signal, &signal, &retain);
453 void flush_itimer_signals(void)
455 struct task_struct *tsk = current;
458 spin_lock_irqsave(&tsk->sighand->siglock, flags);
459 __flush_itimer_signals(&tsk->pending);
460 __flush_itimer_signals(&tsk->signal->shared_pending);
461 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
464 void ignore_signals(struct task_struct *t)
468 for (i = 0; i < _NSIG; ++i)
469 t->sighand->action[i].sa.sa_handler = SIG_IGN;
475 * Flush all handlers for a task.
479 flush_signal_handlers(struct task_struct *t, int force_default)
482 struct k_sigaction *ka = &t->sighand->action[0];
483 for (i = _NSIG ; i != 0 ; i--) {
484 if (force_default || ka->sa.sa_handler != SIG_IGN)
485 ka->sa.sa_handler = SIG_DFL;
487 #ifdef __ARCH_HAS_SA_RESTORER
488 ka->sa.sa_restorer = NULL;
490 sigemptyset(&ka->sa.sa_mask);
495 int unhandled_signal(struct task_struct *tsk, int sig)
497 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
498 if (is_global_init(tsk))
500 if (handler != SIG_IGN && handler != SIG_DFL)
502 /* if ptraced, let the tracer determine */
506 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
509 struct sigqueue *q, *first = NULL;
512 * Collect the siginfo appropriate to this signal. Check if
513 * there is another siginfo for the same signal.
515 list_for_each_entry(q, &list->list, list) {
516 if (q->info.si_signo == sig) {
523 sigdelset(&list->signal, sig);
527 list_del_init(&first->list);
528 copy_siginfo(info, &first->info);
531 (first->flags & SIGQUEUE_PREALLOC) &&
532 (info->si_code == SI_TIMER) &&
533 (info->si_sys_private);
535 __sigqueue_free(first);
538 * Ok, it wasn't in the queue. This must be
539 * a fast-pathed signal or we must have been
540 * out of queue space. So zero out the info.
542 info->si_signo = sig;
544 info->si_code = SI_USER;
550 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
551 siginfo_t *info, bool *resched_timer)
553 int sig = next_signal(pending, mask);
556 collect_signal(sig, pending, info, resched_timer);
561 * Dequeue a signal and return the element to the caller, which is
562 * expected to free it.
564 * All callers have to hold the siglock.
566 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
568 bool resched_timer = false;
571 /* We only dequeue private signals from ourselves, we don't let
572 * signalfd steal them
574 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
576 signr = __dequeue_signal(&tsk->signal->shared_pending,
577 mask, info, &resched_timer);
581 * itimers are process shared and we restart periodic
582 * itimers in the signal delivery path to prevent DoS
583 * attacks in the high resolution timer case. This is
584 * compliant with the old way of self-restarting
585 * itimers, as the SIGALRM is a legacy signal and only
586 * queued once. Changing the restart behaviour to
587 * restart the timer in the signal dequeue path is
588 * reducing the timer noise on heavy loaded !highres
591 if (unlikely(signr == SIGALRM)) {
592 struct hrtimer *tmr = &tsk->signal->real_timer;
594 if (!hrtimer_is_queued(tmr) &&
595 tsk->signal->it_real_incr.tv64 != 0) {
596 hrtimer_forward(tmr, tmr->base->get_time(),
597 tsk->signal->it_real_incr);
598 hrtimer_restart(tmr);
607 if (unlikely(sig_kernel_stop(signr))) {
609 * Set a marker that we have dequeued a stop signal. Our
610 * caller might release the siglock and then the pending
611 * stop signal it is about to process is no longer in the
612 * pending bitmasks, but must still be cleared by a SIGCONT
613 * (and overruled by a SIGKILL). So those cases clear this
614 * shared flag after we've set it. Note that this flag may
615 * remain set after the signal we return is ignored or
616 * handled. That doesn't matter because its only purpose
617 * is to alert stop-signal processing code when another
618 * processor has come along and cleared the flag.
620 current->jobctl |= JOBCTL_STOP_DEQUEUED;
624 * Release the siglock to ensure proper locking order
625 * of timer locks outside of siglocks. Note, we leave
626 * irqs disabled here, since the posix-timers code is
627 * about to disable them again anyway.
629 spin_unlock(&tsk->sighand->siglock);
630 do_schedule_next_timer(info);
631 spin_lock(&tsk->sighand->siglock);
637 * Tell a process that it has a new active signal..
639 * NOTE! we rely on the previous spin_lock to
640 * lock interrupts for us! We can only be called with
641 * "siglock" held, and the local interrupt must
642 * have been disabled when that got acquired!
644 * No need to set need_resched since signal event passing
645 * goes through ->blocked
647 void signal_wake_up_state(struct task_struct *t, unsigned int state)
649 set_tsk_thread_flag(t, TIF_SIGPENDING);
651 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
652 * case. We don't check t->state here because there is a race with it
653 * executing another processor and just now entering stopped state.
654 * By using wake_up_state, we ensure the process will wake up and
655 * handle its death signal.
657 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
662 * Remove signals in mask from the pending set and queue.
663 * Returns 1 if any signals were found.
665 * All callers must be holding the siglock.
667 static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
669 struct sigqueue *q, *n;
672 sigandsets(&m, mask, &s->signal);
673 if (sigisemptyset(&m))
676 sigandnsets(&s->signal, &s->signal, mask);
677 list_for_each_entry_safe(q, n, &s->list, list) {
678 if (sigismember(mask, q->info.si_signo)) {
679 list_del_init(&q->list);
686 static inline int is_si_special(const struct siginfo *info)
688 return info <= SEND_SIG_FORCED;
691 static inline bool si_fromuser(const struct siginfo *info)
693 return info == SEND_SIG_NOINFO ||
694 (!is_si_special(info) && SI_FROMUSER(info));
698 * called with RCU read lock from check_kill_permission()
700 static int kill_ok_by_cred(struct task_struct *t)
702 const struct cred *cred = current_cred();
703 const struct cred *tcred = __task_cred(t);
705 if (uid_eq(cred->euid, tcred->suid) ||
706 uid_eq(cred->euid, tcred->uid) ||
707 uid_eq(cred->uid, tcred->suid) ||
708 uid_eq(cred->uid, tcred->uid))
711 if (ns_capable(tcred->user_ns, CAP_KILL))
718 * Bad permissions for sending the signal
719 * - the caller must hold the RCU read lock
721 static int check_kill_permission(int sig, struct siginfo *info,
722 struct task_struct *t)
727 if (!valid_signal(sig))
730 if (!si_fromuser(info))
733 error = audit_signal_info(sig, t); /* Let audit system see the signal */
737 if (!same_thread_group(current, t) &&
738 !kill_ok_by_cred(t)) {
741 sid = task_session(t);
743 * We don't return the error if sid == NULL. The
744 * task was unhashed, the caller must notice this.
746 if (!sid || sid == task_session(current))
753 return security_task_kill(t, info, sig, 0);
757 * ptrace_trap_notify - schedule trap to notify ptracer
758 * @t: tracee wanting to notify tracer
760 * This function schedules sticky ptrace trap which is cleared on the next
761 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
764 * If @t is running, STOP trap will be taken. If trapped for STOP and
765 * ptracer is listening for events, tracee is woken up so that it can
766 * re-trap for the new event. If trapped otherwise, STOP trap will be
767 * eventually taken without returning to userland after the existing traps
768 * are finished by PTRACE_CONT.
771 * Must be called with @task->sighand->siglock held.
773 static void ptrace_trap_notify(struct task_struct *t)
775 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
776 assert_spin_locked(&t->sighand->siglock);
778 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
779 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
783 * Handle magic process-wide effects of stop/continue signals. Unlike
784 * the signal actions, these happen immediately at signal-generation
785 * time regardless of blocking, ignoring, or handling. This does the
786 * actual continuing for SIGCONT, but not the actual stopping for stop
787 * signals. The process stop is done as a signal action for SIG_DFL.
789 * Returns true if the signal should be actually delivered, otherwise
790 * it should be dropped.
792 static bool prepare_signal(int sig, struct task_struct *p, bool force)
794 struct signal_struct *signal = p->signal;
795 struct task_struct *t;
798 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
799 if (!(signal->flags & SIGNAL_GROUP_EXIT))
800 return sig == SIGKILL;
802 * The process is in the middle of dying, nothing to do.
804 } else if (sig_kernel_stop(sig)) {
806 * This is a stop signal. Remove SIGCONT from all queues.
808 siginitset(&flush, sigmask(SIGCONT));
809 flush_sigqueue_mask(&flush, &signal->shared_pending);
810 for_each_thread(p, t)
811 flush_sigqueue_mask(&flush, &t->pending);
812 } else if (sig == SIGCONT) {
815 * Remove all stop signals from all queues, wake all threads.
817 siginitset(&flush, SIG_KERNEL_STOP_MASK);
818 flush_sigqueue_mask(&flush, &signal->shared_pending);
819 for_each_thread(p, t) {
820 flush_sigqueue_mask(&flush, &t->pending);
821 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
822 if (likely(!(t->ptrace & PT_SEIZED)))
823 wake_up_state(t, __TASK_STOPPED);
825 ptrace_trap_notify(t);
829 * Notify the parent with CLD_CONTINUED if we were stopped.
831 * If we were in the middle of a group stop, we pretend it
832 * was already finished, and then continued. Since SIGCHLD
833 * doesn't queue we report only CLD_STOPPED, as if the next
834 * CLD_CONTINUED was dropped.
837 if (signal->flags & SIGNAL_STOP_STOPPED)
838 why |= SIGNAL_CLD_CONTINUED;
839 else if (signal->group_stop_count)
840 why |= SIGNAL_CLD_STOPPED;
844 * The first thread which returns from do_signal_stop()
845 * will take ->siglock, notice SIGNAL_CLD_MASK, and
846 * notify its parent. See get_signal_to_deliver().
848 signal->flags = why | SIGNAL_STOP_CONTINUED;
849 signal->group_stop_count = 0;
850 signal->group_exit_code = 0;
854 return !sig_ignored(p, sig, force);
858 * Test if P wants to take SIG. After we've checked all threads with this,
859 * it's equivalent to finding no threads not blocking SIG. Any threads not
860 * blocking SIG were ruled out because they are not running and already
861 * have pending signals. Such threads will dequeue from the shared queue
862 * as soon as they're available, so putting the signal on the shared queue
863 * will be equivalent to sending it to one such thread.
865 static inline int wants_signal(int sig, struct task_struct *p)
867 if (sigismember(&p->blocked, sig))
869 if (p->flags & PF_EXITING)
873 if (task_is_stopped_or_traced(p))
875 return task_curr(p) || !signal_pending(p);
878 static void complete_signal(int sig, struct task_struct *p, int group)
880 struct signal_struct *signal = p->signal;
881 struct task_struct *t;
884 * Now find a thread we can wake up to take the signal off the queue.
886 * If the main thread wants the signal, it gets first crack.
887 * Probably the least surprising to the average bear.
889 if (wants_signal(sig, p))
891 else if (!group || thread_group_empty(p))
893 * There is just one thread and it does not need to be woken.
894 * It will dequeue unblocked signals before it runs again.
899 * Otherwise try to find a suitable thread.
901 t = signal->curr_target;
902 while (!wants_signal(sig, t)) {
904 if (t == signal->curr_target)
906 * No thread needs to be woken.
907 * Any eligible threads will see
908 * the signal in the queue soon.
912 signal->curr_target = t;
916 * Found a killable thread. If the signal will be fatal,
917 * then start taking the whole group down immediately.
919 if (sig_fatal(p, sig) &&
920 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
921 !sigismember(&t->real_blocked, sig) &&
922 (sig == SIGKILL || !t->ptrace)) {
924 * This signal will be fatal to the whole group.
926 if (!sig_kernel_coredump(sig)) {
928 * Start a group exit and wake everybody up.
929 * This way we don't have other threads
930 * running and doing things after a slower
931 * thread has the fatal signal pending.
933 signal->flags = SIGNAL_GROUP_EXIT;
934 signal->group_exit_code = sig;
935 signal->group_stop_count = 0;
938 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
939 sigaddset(&t->pending.signal, SIGKILL);
940 signal_wake_up(t, 1);
941 } while_each_thread(p, t);
947 * The signal is already in the shared-pending queue.
948 * Tell the chosen thread to wake up and dequeue it.
950 signal_wake_up(t, sig == SIGKILL);
954 static inline int legacy_queue(struct sigpending *signals, int sig)
956 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
959 #ifdef CONFIG_USER_NS
960 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
962 if (current_user_ns() == task_cred_xxx(t, user_ns))
965 if (SI_FROMKERNEL(info))
969 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
970 make_kuid(current_user_ns(), info->si_uid));
974 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
980 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
981 int group, int from_ancestor_ns)
983 struct sigpending *pending;
988 assert_spin_locked(&t->sighand->siglock);
990 result = TRACE_SIGNAL_IGNORED;
991 if (!prepare_signal(sig, t,
992 from_ancestor_ns || (info == SEND_SIG_FORCED)))
995 pending = group ? &t->signal->shared_pending : &t->pending;
997 * Short-circuit ignored signals and support queuing
998 * exactly one non-rt signal, so that we can get more
999 * detailed information about the cause of the signal.
1001 result = TRACE_SIGNAL_ALREADY_PENDING;
1002 if (legacy_queue(pending, sig))
1005 result = TRACE_SIGNAL_DELIVERED;
1007 * fast-pathed signals for kernel-internal things like SIGSTOP
1010 if (info == SEND_SIG_FORCED)
1014 * Real-time signals must be queued if sent by sigqueue, or
1015 * some other real-time mechanism. It is implementation
1016 * defined whether kill() does so. We attempt to do so, on
1017 * the principle of least surprise, but since kill is not
1018 * allowed to fail with EAGAIN when low on memory we just
1019 * make sure at least one signal gets delivered and don't
1020 * pass on the info struct.
1023 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1025 override_rlimit = 0;
1027 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
1030 list_add_tail(&q->list, &pending->list);
1031 switch ((unsigned long) info) {
1032 case (unsigned long) SEND_SIG_NOINFO:
1033 q->info.si_signo = sig;
1034 q->info.si_errno = 0;
1035 q->info.si_code = SI_USER;
1036 q->info.si_pid = task_tgid_nr_ns(current,
1037 task_active_pid_ns(t));
1038 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1040 case (unsigned long) SEND_SIG_PRIV:
1041 q->info.si_signo = sig;
1042 q->info.si_errno = 0;
1043 q->info.si_code = SI_KERNEL;
1048 copy_siginfo(&q->info, info);
1049 if (from_ancestor_ns)
1054 userns_fixup_signal_uid(&q->info, t);
1056 } else if (!is_si_special(info)) {
1057 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1059 * Queue overflow, abort. We may abort if the
1060 * signal was rt and sent by user using something
1061 * other than kill().
1063 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1068 * This is a silent loss of information. We still
1069 * send the signal, but the *info bits are lost.
1071 result = TRACE_SIGNAL_LOSE_INFO;
1076 signalfd_notify(t, sig);
1077 sigaddset(&pending->signal, sig);
1078 complete_signal(sig, t, group);
1080 trace_signal_generate(sig, info, t, group, result);
1084 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
1087 int from_ancestor_ns = 0;
1089 #ifdef CONFIG_PID_NS
1090 from_ancestor_ns = si_fromuser(info) &&
1091 !task_pid_nr_ns(current, task_active_pid_ns(t));
1094 return __send_signal(sig, info, t, group, from_ancestor_ns);
1097 static void print_fatal_signal(int signr)
1099 struct pt_regs *regs = signal_pt_regs();
1100 printk(KERN_INFO "potentially unexpected fatal signal %d.\n", signr);
1102 #if defined(__i386__) && !defined(__arch_um__)
1103 printk(KERN_INFO "code at %08lx: ", regs->ip);
1106 for (i = 0; i < 16; i++) {
1109 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1111 printk(KERN_CONT "%02x ", insn);
1114 printk(KERN_CONT "\n");
1121 static int __init setup_print_fatal_signals(char *str)
1123 get_option (&str, &print_fatal_signals);
1128 __setup("print-fatal-signals=", setup_print_fatal_signals);
1131 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1133 return send_signal(sig, info, p, 1);
1137 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1139 return send_signal(sig, info, t, 0);
1142 int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1145 unsigned long flags;
1148 if (lock_task_sighand(p, &flags)) {
1149 ret = send_signal(sig, info, p, group);
1150 unlock_task_sighand(p, &flags);
1157 * Force a signal that the process can't ignore: if necessary
1158 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1160 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1161 * since we do not want to have a signal handler that was blocked
1162 * be invoked when user space had explicitly blocked it.
1164 * We don't want to have recursive SIGSEGV's etc, for example,
1165 * that is why we also clear SIGNAL_UNKILLABLE.
1168 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1170 unsigned long int flags;
1171 int ret, blocked, ignored;
1172 struct k_sigaction *action;
1174 spin_lock_irqsave(&t->sighand->siglock, flags);
1175 action = &t->sighand->action[sig-1];
1176 ignored = action->sa.sa_handler == SIG_IGN;
1177 blocked = sigismember(&t->blocked, sig);
1178 if (blocked || ignored) {
1179 action->sa.sa_handler = SIG_DFL;
1181 sigdelset(&t->blocked, sig);
1182 recalc_sigpending_and_wake(t);
1185 if (action->sa.sa_handler == SIG_DFL)
1186 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1187 ret = specific_send_sig_info(sig, info, t);
1188 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1194 * Nuke all other threads in the group.
1196 int zap_other_threads(struct task_struct *p)
1198 struct task_struct *t = p;
1201 p->signal->group_stop_count = 0;
1203 while_each_thread(p, t) {
1204 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1207 /* Don't bother with already dead threads */
1210 sigaddset(&t->pending.signal, SIGKILL);
1211 signal_wake_up(t, 1);
1217 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1218 unsigned long *flags)
1220 struct sighand_struct *sighand;
1224 * Disable interrupts early to avoid deadlocks.
1225 * See rcu_read_unlock() comment header for details.
1227 local_irq_save(*flags);
1229 sighand = rcu_dereference(tsk->sighand);
1230 if (unlikely(sighand == NULL)) {
1232 local_irq_restore(*flags);
1236 * This sighand can be already freed and even reused, but
1237 * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which
1238 * initializes ->siglock: this slab can't go away, it has
1239 * the same object type, ->siglock can't be reinitialized.
1241 * We need to ensure that tsk->sighand is still the same
1242 * after we take the lock, we can race with de_thread() or
1243 * __exit_signal(). In the latter case the next iteration
1244 * must see ->sighand == NULL.
1246 spin_lock(&sighand->siglock);
1247 if (likely(sighand == tsk->sighand)) {
1251 spin_unlock(&sighand->siglock);
1253 local_irq_restore(*flags);
1260 * send signal info to all the members of a group
1262 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1267 ret = check_kill_permission(sig, info, p);
1271 ret = do_send_sig_info(sig, info, p, true);
1277 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1278 * control characters do (^C, ^Z etc)
1279 * - the caller must hold at least a readlock on tasklist_lock
1281 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1283 struct task_struct *p = NULL;
1284 int retval, success;
1288 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1289 int err = group_send_sig_info(sig, info, p);
1292 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1293 return success ? 0 : retval;
1296 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1299 struct task_struct *p;
1303 p = pid_task(pid, PIDTYPE_PID);
1305 error = group_send_sig_info(sig, info, p);
1307 if (likely(!p || error != -ESRCH))
1311 * The task was unhashed in between, try again. If it
1312 * is dead, pid_task() will return NULL, if we race with
1313 * de_thread() it will find the new leader.
1318 int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1322 error = kill_pid_info(sig, info, find_vpid(pid));
1327 static int kill_as_cred_perm(const struct cred *cred,
1328 struct task_struct *target)
1330 const struct cred *pcred = __task_cred(target);
1331 if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
1332 !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid))
1337 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1338 int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
1339 const struct cred *cred, u32 secid)
1342 struct task_struct *p;
1343 unsigned long flags;
1345 if (!valid_signal(sig))
1349 p = pid_task(pid, PIDTYPE_PID);
1354 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
1358 ret = security_task_kill(p, info, sig, secid);
1363 if (lock_task_sighand(p, &flags)) {
1364 ret = __send_signal(sig, info, p, 1, 0);
1365 unlock_task_sighand(p, &flags);
1373 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
1376 * kill_something_info() interprets pid in interesting ways just like kill(2).
1378 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1379 * is probably wrong. Should make it like BSD or SYSV.
1382 static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
1388 ret = kill_pid_info(sig, info, find_vpid(pid));
1393 read_lock(&tasklist_lock);
1395 ret = __kill_pgrp_info(sig, info,
1396 pid ? find_vpid(-pid) : task_pgrp(current));
1398 int retval = 0, count = 0;
1399 struct task_struct * p;
1401 for_each_process(p) {
1402 if (task_pid_vnr(p) > 1 &&
1403 !same_thread_group(p, current)) {
1404 int err = group_send_sig_info(sig, info, p);
1410 ret = count ? retval : -ESRCH;
1412 read_unlock(&tasklist_lock);
1418 * These are for backward compatibility with the rest of the kernel source.
1421 int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1424 * Make sure legacy kernel users don't send in bad values
1425 * (normal paths check this in check_kill_permission).
1427 if (!valid_signal(sig))
1430 return do_send_sig_info(sig, info, p, false);
1433 #define __si_special(priv) \
1434 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1437 send_sig(int sig, struct task_struct *p, int priv)
1439 return send_sig_info(sig, __si_special(priv), p);
1443 force_sig(int sig, struct task_struct *p)
1445 force_sig_info(sig, SEND_SIG_PRIV, p);
1449 * When things go south during signal handling, we
1450 * will force a SIGSEGV. And if the signal that caused
1451 * the problem was already a SIGSEGV, we'll want to
1452 * make sure we don't even try to deliver the signal..
1455 force_sigsegv(int sig, struct task_struct *p)
1457 if (sig == SIGSEGV) {
1458 unsigned long flags;
1459 spin_lock_irqsave(&p->sighand->siglock, flags);
1460 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1461 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1463 force_sig(SIGSEGV, p);
1467 int kill_pgrp(struct pid *pid, int sig, int priv)
1471 read_lock(&tasklist_lock);
1472 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1473 read_unlock(&tasklist_lock);
1477 EXPORT_SYMBOL(kill_pgrp);
1479 int kill_pid(struct pid *pid, int sig, int priv)
1481 return kill_pid_info(sig, __si_special(priv), pid);
1483 EXPORT_SYMBOL(kill_pid);
1486 * These functions support sending signals using preallocated sigqueue
1487 * structures. This is needed "because realtime applications cannot
1488 * afford to lose notifications of asynchronous events, like timer
1489 * expirations or I/O completions". In the case of POSIX Timers
1490 * we allocate the sigqueue structure from the timer_create. If this
1491 * allocation fails we are able to report the failure to the application
1492 * with an EAGAIN error.
1494 struct sigqueue *sigqueue_alloc(void)
1496 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1499 q->flags |= SIGQUEUE_PREALLOC;
1504 void sigqueue_free(struct sigqueue *q)
1506 unsigned long flags;
1507 spinlock_t *lock = ¤t->sighand->siglock;
1509 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1511 * We must hold ->siglock while testing q->list
1512 * to serialize with collect_signal() or with
1513 * __exit_signal()->flush_sigqueue().
1515 spin_lock_irqsave(lock, flags);
1516 q->flags &= ~SIGQUEUE_PREALLOC;
1518 * If it is queued it will be freed when dequeued,
1519 * like the "regular" sigqueue.
1521 if (!list_empty(&q->list))
1523 spin_unlock_irqrestore(lock, flags);
1529 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1531 int sig = q->info.si_signo;
1532 struct sigpending *pending;
1533 unsigned long flags;
1536 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1539 if (!likely(lock_task_sighand(t, &flags)))
1542 ret = 1; /* the signal is ignored */
1543 result = TRACE_SIGNAL_IGNORED;
1544 if (!prepare_signal(sig, t, false))
1548 if (unlikely(!list_empty(&q->list))) {
1550 * If an SI_TIMER entry is already queue just increment
1551 * the overrun count.
1553 BUG_ON(q->info.si_code != SI_TIMER);
1554 q->info.si_overrun++;
1555 result = TRACE_SIGNAL_ALREADY_PENDING;
1558 q->info.si_overrun = 0;
1560 signalfd_notify(t, sig);
1561 pending = group ? &t->signal->shared_pending : &t->pending;
1562 list_add_tail(&q->list, &pending->list);
1563 sigaddset(&pending->signal, sig);
1564 complete_signal(sig, t, group);
1565 result = TRACE_SIGNAL_DELIVERED;
1567 trace_signal_generate(sig, &q->info, t, group, result);
1568 unlock_task_sighand(t, &flags);
1574 * Let a parent know about the death of a child.
1575 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1577 * Returns true if our parent ignored us and so we've switched to
1580 bool do_notify_parent(struct task_struct *tsk, int sig)
1582 struct siginfo info;
1583 unsigned long flags;
1584 struct sighand_struct *psig;
1585 bool autoreap = false;
1586 cputime_t utime, stime;
1590 /* do_notify_parent_cldstop should have been called instead. */
1591 BUG_ON(task_is_stopped_or_traced(tsk));
1593 BUG_ON(!tsk->ptrace &&
1594 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1596 if (sig != SIGCHLD) {
1598 * This is only possible if parent == real_parent.
1599 * Check if it has changed security domain.
1601 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1605 info.si_signo = sig;
1608 * We are under tasklist_lock here so our parent is tied to
1609 * us and cannot change.
1611 * task_active_pid_ns will always return the same pid namespace
1612 * until a task passes through release_task.
1614 * write_lock() currently calls preempt_disable() which is the
1615 * same as rcu_read_lock(), but according to Oleg, this is not
1616 * correct to rely on this
1619 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1620 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1624 task_cputime(tsk, &utime, &stime);
1625 info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime);
1626 info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime);
1628 info.si_status = tsk->exit_code & 0x7f;
1629 if (tsk->exit_code & 0x80)
1630 info.si_code = CLD_DUMPED;
1631 else if (tsk->exit_code & 0x7f)
1632 info.si_code = CLD_KILLED;
1634 info.si_code = CLD_EXITED;
1635 info.si_status = tsk->exit_code >> 8;
1638 psig = tsk->parent->sighand;
1639 spin_lock_irqsave(&psig->siglock, flags);
1640 if (!tsk->ptrace && sig == SIGCHLD &&
1641 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1642 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1644 * We are exiting and our parent doesn't care. POSIX.1
1645 * defines special semantics for setting SIGCHLD to SIG_IGN
1646 * or setting the SA_NOCLDWAIT flag: we should be reaped
1647 * automatically and not left for our parent's wait4 call.
1648 * Rather than having the parent do it as a magic kind of
1649 * signal handler, we just set this to tell do_exit that we
1650 * can be cleaned up without becoming a zombie. Note that
1651 * we still call __wake_up_parent in this case, because a
1652 * blocked sys_wait4 might now return -ECHILD.
1654 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1655 * is implementation-defined: we do (if you don't want
1656 * it, just use SIG_IGN instead).
1659 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1662 if (valid_signal(sig) && sig)
1663 __group_send_sig_info(sig, &info, tsk->parent);
1664 __wake_up_parent(tsk, tsk->parent);
1665 spin_unlock_irqrestore(&psig->siglock, flags);
1671 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1672 * @tsk: task reporting the state change
1673 * @for_ptracer: the notification is for ptracer
1674 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1676 * Notify @tsk's parent that the stopped/continued state has changed. If
1677 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1678 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1681 * Must be called with tasklist_lock at least read locked.
1683 static void do_notify_parent_cldstop(struct task_struct *tsk,
1684 bool for_ptracer, int why)
1686 struct siginfo info;
1687 unsigned long flags;
1688 struct task_struct *parent;
1689 struct sighand_struct *sighand;
1690 cputime_t utime, stime;
1693 parent = tsk->parent;
1695 tsk = tsk->group_leader;
1696 parent = tsk->real_parent;
1699 info.si_signo = SIGCHLD;
1702 * see comment in do_notify_parent() about the following 4 lines
1705 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
1706 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
1709 task_cputime(tsk, &utime, &stime);
1710 info.si_utime = cputime_to_clock_t(utime);
1711 info.si_stime = cputime_to_clock_t(stime);
1716 info.si_status = SIGCONT;
1719 info.si_status = tsk->signal->group_exit_code & 0x7f;
1722 info.si_status = tsk->exit_code & 0x7f;
1728 sighand = parent->sighand;
1729 spin_lock_irqsave(&sighand->siglock, flags);
1730 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1731 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1732 __group_send_sig_info(SIGCHLD, &info, parent);
1734 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1736 __wake_up_parent(tsk, parent);
1737 spin_unlock_irqrestore(&sighand->siglock, flags);
1740 static inline int may_ptrace_stop(void)
1742 if (!likely(current->ptrace))
1745 * Are we in the middle of do_coredump?
1746 * If so and our tracer is also part of the coredump stopping
1747 * is a deadlock situation, and pointless because our tracer
1748 * is dead so don't allow us to stop.
1749 * If SIGKILL was already sent before the caller unlocked
1750 * ->siglock we must see ->core_state != NULL. Otherwise it
1751 * is safe to enter schedule().
1753 * This is almost outdated, a task with the pending SIGKILL can't
1754 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1755 * after SIGKILL was already dequeued.
1757 if (unlikely(current->mm->core_state) &&
1758 unlikely(current->mm == current->parent->mm))
1765 * Return non-zero if there is a SIGKILL that should be waking us up.
1766 * Called with the siglock held.
1768 static int sigkill_pending(struct task_struct *tsk)
1770 return sigismember(&tsk->pending.signal, SIGKILL) ||
1771 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
1775 * This must be called with current->sighand->siglock held.
1777 * This should be the path for all ptrace stops.
1778 * We always set current->last_siginfo while stopped here.
1779 * That makes it a way to test a stopped process for
1780 * being ptrace-stopped vs being job-control-stopped.
1782 * If we actually decide not to stop at all because the tracer
1783 * is gone, we keep current->exit_code unless clear_code.
1785 static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
1786 __releases(¤t->sighand->siglock)
1787 __acquires(¤t->sighand->siglock)
1789 bool gstop_done = false;
1791 if (arch_ptrace_stop_needed(exit_code, info)) {
1793 * The arch code has something special to do before a
1794 * ptrace stop. This is allowed to block, e.g. for faults
1795 * on user stack pages. We can't keep the siglock while
1796 * calling arch_ptrace_stop, so we must release it now.
1797 * To preserve proper semantics, we must do this before
1798 * any signal bookkeeping like checking group_stop_count.
1799 * Meanwhile, a SIGKILL could come in before we retake the
1800 * siglock. That must prevent us from sleeping in TASK_TRACED.
1801 * So after regaining the lock, we must check for SIGKILL.
1803 spin_unlock_irq(¤t->sighand->siglock);
1804 arch_ptrace_stop(exit_code, info);
1805 spin_lock_irq(¤t->sighand->siglock);
1806 if (sigkill_pending(current))
1811 * We're committing to trapping. TRACED should be visible before
1812 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1813 * Also, transition to TRACED and updates to ->jobctl should be
1814 * atomic with respect to siglock and should be done after the arch
1815 * hook as siglock is released and regrabbed across it.
1817 set_current_state(TASK_TRACED);
1819 current->last_siginfo = info;
1820 current->exit_code = exit_code;
1823 * If @why is CLD_STOPPED, we're trapping to participate in a group
1824 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1825 * across siglock relocks since INTERRUPT was scheduled, PENDING
1826 * could be clear now. We act as if SIGCONT is received after
1827 * TASK_TRACED is entered - ignore it.
1829 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
1830 gstop_done = task_participate_group_stop(current);
1832 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1833 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
1834 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
1835 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
1837 /* entering a trap, clear TRAPPING */
1838 task_clear_jobctl_trapping(current);
1840 spin_unlock_irq(¤t->sighand->siglock);
1841 read_lock(&tasklist_lock);
1842 if (may_ptrace_stop()) {
1844 * Notify parents of the stop.
1846 * While ptraced, there are two parents - the ptracer and
1847 * the real_parent of the group_leader. The ptracer should
1848 * know about every stop while the real parent is only
1849 * interested in the completion of group stop. The states
1850 * for the two don't interact with each other. Notify
1851 * separately unless they're gonna be duplicates.
1853 do_notify_parent_cldstop(current, true, why);
1854 if (gstop_done && ptrace_reparented(current))
1855 do_notify_parent_cldstop(current, false, why);
1858 * Don't want to allow preemption here, because
1859 * sys_ptrace() needs this task to be inactive.
1861 * XXX: implement read_unlock_no_resched().
1864 read_unlock(&tasklist_lock);
1865 preempt_enable_no_resched();
1866 freezable_schedule();
1869 * By the time we got the lock, our tracer went away.
1870 * Don't drop the lock yet, another tracer may come.
1872 * If @gstop_done, the ptracer went away between group stop
1873 * completion and here. During detach, it would have set
1874 * JOBCTL_STOP_PENDING on us and we'll re-enter
1875 * TASK_STOPPED in do_signal_stop() on return, so notifying
1876 * the real parent of the group stop completion is enough.
1879 do_notify_parent_cldstop(current, false, why);
1881 /* tasklist protects us from ptrace_freeze_traced() */
1882 __set_current_state(TASK_RUNNING);
1884 current->exit_code = 0;
1885 read_unlock(&tasklist_lock);
1889 * We are back. Now reacquire the siglock before touching
1890 * last_siginfo, so that we are sure to have synchronized with
1891 * any signal-sending on another CPU that wants to examine it.
1893 spin_lock_irq(¤t->sighand->siglock);
1894 current->last_siginfo = NULL;
1896 /* LISTENING can be set only during STOP traps, clear it */
1897 current->jobctl &= ~JOBCTL_LISTENING;
1900 * Queued signals ignored us while we were stopped for tracing.
1901 * So check for any that we should take before resuming user mode.
1902 * This sets TIF_SIGPENDING, but never clears it.
1904 recalc_sigpending_tsk(current);
1907 static void ptrace_do_notify(int signr, int exit_code, int why)
1911 memset(&info, 0, sizeof info);
1912 info.si_signo = signr;
1913 info.si_code = exit_code;
1914 info.si_pid = task_pid_vnr(current);
1915 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1917 /* Let the debugger run. */
1918 ptrace_stop(exit_code, why, 1, &info);
1921 void ptrace_notify(int exit_code)
1923 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1924 if (unlikely(current->task_works))
1927 spin_lock_irq(¤t->sighand->siglock);
1928 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
1929 spin_unlock_irq(¤t->sighand->siglock);
1933 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1934 * @signr: signr causing group stop if initiating
1936 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1937 * and participate in it. If already set, participate in the existing
1938 * group stop. If participated in a group stop (and thus slept), %true is
1939 * returned with siglock released.
1941 * If ptraced, this function doesn't handle stop itself. Instead,
1942 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1943 * untouched. The caller must ensure that INTERRUPT trap handling takes
1944 * places afterwards.
1947 * Must be called with @current->sighand->siglock held, which is released
1951 * %false if group stop is already cancelled or ptrace trap is scheduled.
1952 * %true if participated in group stop.
1954 static bool do_signal_stop(int signr)
1955 __releases(¤t->sighand->siglock)
1957 struct signal_struct *sig = current->signal;
1959 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
1960 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
1961 struct task_struct *t;
1963 /* signr will be recorded in task->jobctl for retries */
1964 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
1966 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
1967 unlikely(signal_group_exit(sig)))
1970 * There is no group stop already in progress. We must
1973 * While ptraced, a task may be resumed while group stop is
1974 * still in effect and then receive a stop signal and
1975 * initiate another group stop. This deviates from the
1976 * usual behavior as two consecutive stop signals can't
1977 * cause two group stops when !ptraced. That is why we
1978 * also check !task_is_stopped(t) below.
1980 * The condition can be distinguished by testing whether
1981 * SIGNAL_STOP_STOPPED is already set. Don't generate
1982 * group_exit_code in such case.
1984 * This is not necessary for SIGNAL_STOP_CONTINUED because
1985 * an intervening stop signal is required to cause two
1986 * continued events regardless of ptrace.
1988 if (!(sig->flags & SIGNAL_STOP_STOPPED))
1989 sig->group_exit_code = signr;
1991 sig->group_stop_count = 0;
1993 if (task_set_jobctl_pending(current, signr | gstop))
1994 sig->group_stop_count++;
1997 while_each_thread(current, t) {
1999 * Setting state to TASK_STOPPED for a group
2000 * stop is always done with the siglock held,
2001 * so this check has no races.
2003 if (!task_is_stopped(t) &&
2004 task_set_jobctl_pending(t, signr | gstop)) {
2005 sig->group_stop_count++;
2006 if (likely(!(t->ptrace & PT_SEIZED)))
2007 signal_wake_up(t, 0);
2009 ptrace_trap_notify(t);
2014 if (likely(!current->ptrace)) {
2018 * If there are no other threads in the group, or if there
2019 * is a group stop in progress and we are the last to stop,
2020 * report to the parent.
2022 if (task_participate_group_stop(current))
2023 notify = CLD_STOPPED;
2025 __set_current_state(TASK_STOPPED);
2026 spin_unlock_irq(¤t->sighand->siglock);
2029 * Notify the parent of the group stop completion. Because
2030 * we're not holding either the siglock or tasklist_lock
2031 * here, ptracer may attach inbetween; however, this is for
2032 * group stop and should always be delivered to the real
2033 * parent of the group leader. The new ptracer will get
2034 * its notification when this task transitions into
2038 read_lock(&tasklist_lock);
2039 do_notify_parent_cldstop(current, false, notify);
2040 read_unlock(&tasklist_lock);
2043 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2044 freezable_schedule();
2048 * While ptraced, group stop is handled by STOP trap.
2049 * Schedule it and let the caller deal with it.
2051 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2057 * do_jobctl_trap - take care of ptrace jobctl traps
2059 * When PT_SEIZED, it's used for both group stop and explicit
2060 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2061 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2062 * the stop signal; otherwise, %SIGTRAP.
2064 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2065 * number as exit_code and no siginfo.
2068 * Must be called with @current->sighand->siglock held, which may be
2069 * released and re-acquired before returning with intervening sleep.
2071 static void do_jobctl_trap(void)
2073 struct signal_struct *signal = current->signal;
2074 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2076 if (current->ptrace & PT_SEIZED) {
2077 if (!signal->group_stop_count &&
2078 !(signal->flags & SIGNAL_STOP_STOPPED))
2080 WARN_ON_ONCE(!signr);
2081 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2084 WARN_ON_ONCE(!signr);
2085 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2086 current->exit_code = 0;
2090 static int ptrace_signal(int signr, siginfo_t *info)
2092 ptrace_signal_deliver();
2094 * We do not check sig_kernel_stop(signr) but set this marker
2095 * unconditionally because we do not know whether debugger will
2096 * change signr. This flag has no meaning unless we are going
2097 * to stop after return from ptrace_stop(). In this case it will
2098 * be checked in do_signal_stop(), we should only stop if it was
2099 * not cleared by SIGCONT while we were sleeping. See also the
2100 * comment in dequeue_signal().
2102 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2103 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2105 /* We're back. Did the debugger cancel the sig? */
2106 signr = current->exit_code;
2110 current->exit_code = 0;
2113 * Update the siginfo structure if the signal has
2114 * changed. If the debugger wanted something
2115 * specific in the siginfo structure then it should
2116 * have updated *info via PTRACE_SETSIGINFO.
2118 if (signr != info->si_signo) {
2119 info->si_signo = signr;
2121 info->si_code = SI_USER;
2123 info->si_pid = task_pid_vnr(current->parent);
2124 info->si_uid = from_kuid_munged(current_user_ns(),
2125 task_uid(current->parent));
2129 /* If the (new) signal is now blocked, requeue it. */
2130 if (sigismember(¤t->blocked, signr)) {
2131 specific_send_sig_info(signr, info, current);
2138 int get_signal(struct ksignal *ksig)
2140 struct sighand_struct *sighand = current->sighand;
2141 struct signal_struct *signal = current->signal;
2144 if (unlikely(current->task_works))
2147 if (unlikely(uprobe_deny_signal()))
2151 * Do this once, we can't return to user-mode if freezing() == T.
2152 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2153 * thus do not need another check after return.
2158 spin_lock_irq(&sighand->siglock);
2160 * Every stopped thread goes here after wakeup. Check to see if
2161 * we should notify the parent, prepare_signal(SIGCONT) encodes
2162 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2164 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2167 if (signal->flags & SIGNAL_CLD_CONTINUED)
2168 why = CLD_CONTINUED;
2172 signal->flags &= ~SIGNAL_CLD_MASK;
2174 spin_unlock_irq(&sighand->siglock);
2177 * Notify the parent that we're continuing. This event is
2178 * always per-process and doesn't make whole lot of sense
2179 * for ptracers, who shouldn't consume the state via
2180 * wait(2) either, but, for backward compatibility, notify
2181 * the ptracer of the group leader too unless it's gonna be
2184 read_lock(&tasklist_lock);
2185 do_notify_parent_cldstop(current, false, why);
2187 if (ptrace_reparented(current->group_leader))
2188 do_notify_parent_cldstop(current->group_leader,
2190 read_unlock(&tasklist_lock);
2196 struct k_sigaction *ka;
2198 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2202 if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
2204 spin_unlock_irq(&sighand->siglock);
2208 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2211 break; /* will return 0 */
2213 if (unlikely(current->ptrace) && signr != SIGKILL) {
2214 signr = ptrace_signal(signr, &ksig->info);
2219 ka = &sighand->action[signr-1];
2221 /* Trace actually delivered signals. */
2222 trace_signal_deliver(signr, &ksig->info, ka);
2224 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2226 if (ka->sa.sa_handler != SIG_DFL) {
2227 /* Run the handler. */
2230 if (ka->sa.sa_flags & SA_ONESHOT)
2231 ka->sa.sa_handler = SIG_DFL;
2233 break; /* will return non-zero "signr" value */
2237 * Now we are doing the default action for this signal.
2239 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2243 * Global init gets no signals it doesn't want.
2244 * Container-init gets no signals it doesn't want from same
2247 * Note that if global/container-init sees a sig_kernel_only()
2248 * signal here, the signal must have been generated internally
2249 * or must have come from an ancestor namespace. In either
2250 * case, the signal cannot be dropped.
2252 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2253 !sig_kernel_only(signr))
2256 if (sig_kernel_stop(signr)) {
2258 * The default action is to stop all threads in
2259 * the thread group. The job control signals
2260 * do nothing in an orphaned pgrp, but SIGSTOP
2261 * always works. Note that siglock needs to be
2262 * dropped during the call to is_orphaned_pgrp()
2263 * because of lock ordering with tasklist_lock.
2264 * This allows an intervening SIGCONT to be posted.
2265 * We need to check for that and bail out if necessary.
2267 if (signr != SIGSTOP) {
2268 spin_unlock_irq(&sighand->siglock);
2270 /* signals can be posted during this window */
2272 if (is_current_pgrp_orphaned())
2275 spin_lock_irq(&sighand->siglock);
2278 if (likely(do_signal_stop(ksig->info.si_signo))) {
2279 /* It released the siglock. */
2284 * We didn't actually stop, due to a race
2285 * with SIGCONT or something like that.
2290 spin_unlock_irq(&sighand->siglock);
2293 * Anything else is fatal, maybe with a core dump.
2295 current->flags |= PF_SIGNALED;
2297 if (sig_kernel_coredump(signr)) {
2298 if (print_fatal_signals)
2299 print_fatal_signal(ksig->info.si_signo);
2300 proc_coredump_connector(current);
2302 * If it was able to dump core, this kills all
2303 * other threads in the group and synchronizes with
2304 * their demise. If we lost the race with another
2305 * thread getting here, it set group_exit_code
2306 * first and our do_group_exit call below will use
2307 * that value and ignore the one we pass it.
2309 do_coredump(&ksig->info);
2313 * Death signals, no core dump.
2315 do_group_exit(ksig->info.si_signo);
2318 spin_unlock_irq(&sighand->siglock);
2321 return ksig->sig > 0;
2325 * signal_delivered -
2326 * @ksig: kernel signal struct
2327 * @stepping: nonzero if debugger single-step or block-step in use
2329 * This function should be called when a signal has successfully been
2330 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2331 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2332 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2334 static void signal_delivered(struct ksignal *ksig, int stepping)
2338 /* A signal was successfully delivered, and the
2339 saved sigmask was stored on the signal frame,
2340 and will be restored by sigreturn. So we can
2341 simply clear the restore sigmask flag. */
2342 clear_restore_sigmask();
2344 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2345 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2346 sigaddset(&blocked, ksig->sig);
2347 set_current_blocked(&blocked);
2348 tracehook_signal_handler(stepping);
2351 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2354 force_sigsegv(ksig->sig, current);
2356 signal_delivered(ksig, stepping);
2360 * It could be that complete_signal() picked us to notify about the
2361 * group-wide signal. Other threads should be notified now to take
2362 * the shared signals in @which since we will not.
2364 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2367 struct task_struct *t;
2369 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2370 if (sigisemptyset(&retarget))
2374 while_each_thread(tsk, t) {
2375 if (t->flags & PF_EXITING)
2378 if (!has_pending_signals(&retarget, &t->blocked))
2380 /* Remove the signals this thread can handle. */
2381 sigandsets(&retarget, &retarget, &t->blocked);
2383 if (!signal_pending(t))
2384 signal_wake_up(t, 0);
2386 if (sigisemptyset(&retarget))
2391 void exit_signals(struct task_struct *tsk)
2397 * @tsk is about to have PF_EXITING set - lock out users which
2398 * expect stable threadgroup.
2400 threadgroup_change_begin(tsk);
2402 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2403 tsk->flags |= PF_EXITING;
2404 threadgroup_change_end(tsk);
2408 spin_lock_irq(&tsk->sighand->siglock);
2410 * From now this task is not visible for group-wide signals,
2411 * see wants_signal(), do_signal_stop().
2413 tsk->flags |= PF_EXITING;
2415 threadgroup_change_end(tsk);
2417 if (!signal_pending(tsk))
2420 unblocked = tsk->blocked;
2421 signotset(&unblocked);
2422 retarget_shared_pending(tsk, &unblocked);
2424 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2425 task_participate_group_stop(tsk))
2426 group_stop = CLD_STOPPED;
2428 spin_unlock_irq(&tsk->sighand->siglock);
2431 * If group stop has completed, deliver the notification. This
2432 * should always go to the real parent of the group leader.
2434 if (unlikely(group_stop)) {
2435 read_lock(&tasklist_lock);
2436 do_notify_parent_cldstop(tsk, false, group_stop);
2437 read_unlock(&tasklist_lock);
2441 EXPORT_SYMBOL(recalc_sigpending);
2442 EXPORT_SYMBOL_GPL(dequeue_signal);
2443 EXPORT_SYMBOL(flush_signals);
2444 EXPORT_SYMBOL(force_sig);
2445 EXPORT_SYMBOL(send_sig);
2446 EXPORT_SYMBOL(send_sig_info);
2447 EXPORT_SYMBOL(sigprocmask);
2450 * System call entry points.
2454 * sys_restart_syscall - restart a system call
2456 SYSCALL_DEFINE0(restart_syscall)
2458 struct restart_block *restart = ¤t->restart_block;
2459 return restart->fn(restart);
2462 long do_no_restart_syscall(struct restart_block *param)
2467 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2469 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2470 sigset_t newblocked;
2471 /* A set of now blocked but previously unblocked signals. */
2472 sigandnsets(&newblocked, newset, ¤t->blocked);
2473 retarget_shared_pending(tsk, &newblocked);
2475 tsk->blocked = *newset;
2476 recalc_sigpending();
2480 * set_current_blocked - change current->blocked mask
2483 * It is wrong to change ->blocked directly, this helper should be used
2484 * to ensure the process can't miss a shared signal we are going to block.
2486 void set_current_blocked(sigset_t *newset)
2488 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2489 __set_current_blocked(newset);
2492 void __set_current_blocked(const sigset_t *newset)
2494 struct task_struct *tsk = current;
2496 spin_lock_irq(&tsk->sighand->siglock);
2497 __set_task_blocked(tsk, newset);
2498 spin_unlock_irq(&tsk->sighand->siglock);
2502 * This is also useful for kernel threads that want to temporarily
2503 * (or permanently) block certain signals.
2505 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2506 * interface happily blocks "unblockable" signals like SIGKILL
2509 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2511 struct task_struct *tsk = current;
2514 /* Lockless, only current can change ->blocked, never from irq */
2516 *oldset = tsk->blocked;
2520 sigorsets(&newset, &tsk->blocked, set);
2523 sigandnsets(&newset, &tsk->blocked, set);
2532 __set_current_blocked(&newset);
2537 * sys_rt_sigprocmask - change the list of currently blocked signals
2538 * @how: whether to add, remove, or set signals
2539 * @nset: stores pending signals
2540 * @oset: previous value of signal mask if non-null
2541 * @sigsetsize: size of sigset_t type
2543 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2544 sigset_t __user *, oset, size_t, sigsetsize)
2546 sigset_t old_set, new_set;
2549 /* XXX: Don't preclude handling different sized sigset_t's. */
2550 if (sigsetsize != sizeof(sigset_t))
2553 old_set = current->blocked;
2556 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2558 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2560 error = sigprocmask(how, &new_set, NULL);
2566 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2573 #ifdef CONFIG_COMPAT
2574 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2575 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2578 sigset_t old_set = current->blocked;
2580 /* XXX: Don't preclude handling different sized sigset_t's. */
2581 if (sigsetsize != sizeof(sigset_t))
2585 compat_sigset_t new32;
2588 if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
2591 sigset_from_compat(&new_set, &new32);
2592 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2594 error = sigprocmask(how, &new_set, NULL);
2599 compat_sigset_t old32;
2600 sigset_to_compat(&old32, &old_set);
2601 if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
2606 return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
2607 (sigset_t __user *)oset, sigsetsize);
2612 static int do_sigpending(void *set, unsigned long sigsetsize)
2614 if (sigsetsize > sizeof(sigset_t))
2617 spin_lock_irq(¤t->sighand->siglock);
2618 sigorsets(set, ¤t->pending.signal,
2619 ¤t->signal->shared_pending.signal);
2620 spin_unlock_irq(¤t->sighand->siglock);
2622 /* Outside the lock because only this thread touches it. */
2623 sigandsets(set, ¤t->blocked, set);
2628 * sys_rt_sigpending - examine a pending signal that has been raised
2630 * @uset: stores pending signals
2631 * @sigsetsize: size of sigset_t type or larger
2633 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
2636 int err = do_sigpending(&set, sigsetsize);
2637 if (!err && copy_to_user(uset, &set, sigsetsize))
2642 #ifdef CONFIG_COMPAT
2643 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
2644 compat_size_t, sigsetsize)
2648 int err = do_sigpending(&set, sigsetsize);
2650 compat_sigset_t set32;
2651 sigset_to_compat(&set32, &set);
2652 /* we can get here only if sigsetsize <= sizeof(set) */
2653 if (copy_to_user(uset, &set32, sigsetsize))
2658 return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
2663 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2665 int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
2669 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2671 if (from->si_code < 0)
2672 return __copy_to_user(to, from, sizeof(siginfo_t))
2675 * If you change siginfo_t structure, please be sure
2676 * this code is fixed accordingly.
2677 * Please remember to update the signalfd_copyinfo() function
2678 * inside fs/signalfd.c too, in case siginfo_t changes.
2679 * It should never copy any pad contained in the structure
2680 * to avoid security leaks, but must copy the generic
2681 * 3 ints plus the relevant union member.
2683 err = __put_user(from->si_signo, &to->si_signo);
2684 err |= __put_user(from->si_errno, &to->si_errno);
2685 err |= __put_user((short)from->si_code, &to->si_code);
2686 switch (from->si_code & __SI_MASK) {
2688 err |= __put_user(from->si_pid, &to->si_pid);
2689 err |= __put_user(from->si_uid, &to->si_uid);
2692 err |= __put_user(from->si_tid, &to->si_tid);
2693 err |= __put_user(from->si_overrun, &to->si_overrun);
2694 err |= __put_user(from->si_ptr, &to->si_ptr);
2697 err |= __put_user(from->si_band, &to->si_band);
2698 err |= __put_user(from->si_fd, &to->si_fd);
2701 err |= __put_user(from->si_addr, &to->si_addr);
2702 #ifdef __ARCH_SI_TRAPNO
2703 err |= __put_user(from->si_trapno, &to->si_trapno);
2705 #ifdef BUS_MCEERR_AO
2707 * Other callers might not initialize the si_lsb field,
2708 * so check explicitly for the right codes here.
2710 if (from->si_signo == SIGBUS &&
2711 (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
2712 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2715 if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) {
2716 err |= __put_user(from->si_lower, &to->si_lower);
2717 err |= __put_user(from->si_upper, &to->si_upper);
2722 err |= __put_user(from->si_pid, &to->si_pid);
2723 err |= __put_user(from->si_uid, &to->si_uid);
2724 err |= __put_user(from->si_status, &to->si_status);
2725 err |= __put_user(from->si_utime, &to->si_utime);
2726 err |= __put_user(from->si_stime, &to->si_stime);
2728 case __SI_RT: /* This is not generated by the kernel as of now. */
2729 case __SI_MESGQ: /* But this is */
2730 err |= __put_user(from->si_pid, &to->si_pid);
2731 err |= __put_user(from->si_uid, &to->si_uid);
2732 err |= __put_user(from->si_ptr, &to->si_ptr);
2734 #ifdef __ARCH_SIGSYS
2736 err |= __put_user(from->si_call_addr, &to->si_call_addr);
2737 err |= __put_user(from->si_syscall, &to->si_syscall);
2738 err |= __put_user(from->si_arch, &to->si_arch);
2741 default: /* this is just in case for now ... */
2742 err |= __put_user(from->si_pid, &to->si_pid);
2743 err |= __put_user(from->si_uid, &to->si_uid);
2752 * do_sigtimedwait - wait for queued signals specified in @which
2753 * @which: queued signals to wait for
2754 * @info: if non-null, the signal's siginfo is returned here
2755 * @ts: upper bound on process time suspension
2757 int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
2758 const struct timespec *ts)
2760 struct task_struct *tsk = current;
2761 long timeout = MAX_SCHEDULE_TIMEOUT;
2762 sigset_t mask = *which;
2766 if (!timespec_valid(ts))
2768 timeout = timespec_to_jiffies(ts);
2770 * We can be close to the next tick, add another one
2771 * to ensure we will wait at least the time asked for.
2773 if (ts->tv_sec || ts->tv_nsec)
2778 * Invert the set of allowed signals to get those we want to block.
2780 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
2783 spin_lock_irq(&tsk->sighand->siglock);
2784 sig = dequeue_signal(tsk, &mask, info);
2785 if (!sig && timeout) {
2787 * None ready, temporarily unblock those we're interested
2788 * while we are sleeping in so that we'll be awakened when
2789 * they arrive. Unblocking is always fine, we can avoid
2790 * set_current_blocked().
2792 tsk->real_blocked = tsk->blocked;
2793 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
2794 recalc_sigpending();
2795 spin_unlock_irq(&tsk->sighand->siglock);
2797 timeout = freezable_schedule_timeout_interruptible(timeout);
2799 spin_lock_irq(&tsk->sighand->siglock);
2800 __set_task_blocked(tsk, &tsk->real_blocked);
2801 sigemptyset(&tsk->real_blocked);
2802 sig = dequeue_signal(tsk, &mask, info);
2804 spin_unlock_irq(&tsk->sighand->siglock);
2808 return timeout ? -EINTR : -EAGAIN;
2812 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2814 * @uthese: queued signals to wait for
2815 * @uinfo: if non-null, the signal's siginfo is returned here
2816 * @uts: upper bound on process time suspension
2817 * @sigsetsize: size of sigset_t type
2819 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2820 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2828 /* XXX: Don't preclude handling different sized sigset_t's. */
2829 if (sigsetsize != sizeof(sigset_t))
2832 if (copy_from_user(&these, uthese, sizeof(these)))
2836 if (copy_from_user(&ts, uts, sizeof(ts)))
2840 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
2842 if (ret > 0 && uinfo) {
2843 if (copy_siginfo_to_user(uinfo, &info))
2851 * sys_kill - send a signal to a process
2852 * @pid: the PID of the process
2853 * @sig: signal to be sent
2855 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2857 struct siginfo info;
2859 info.si_signo = sig;
2861 info.si_code = SI_USER;
2862 info.si_pid = task_tgid_vnr(current);
2863 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2865 return kill_something_info(sig, &info, pid);
2869 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2871 struct task_struct *p;
2875 p = find_task_by_vpid(pid);
2876 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2877 error = check_kill_permission(sig, info, p);
2879 * The null signal is a permissions and process existence
2880 * probe. No signal is actually delivered.
2882 if (!error && sig) {
2883 error = do_send_sig_info(sig, info, p, false);
2885 * If lock_task_sighand() failed we pretend the task
2886 * dies after receiving the signal. The window is tiny,
2887 * and the signal is private anyway.
2889 if (unlikely(error == -ESRCH))
2898 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2900 struct siginfo info = {};
2902 info.si_signo = sig;
2904 info.si_code = SI_TKILL;
2905 info.si_pid = task_tgid_vnr(current);
2906 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2908 return do_send_specific(tgid, pid, sig, &info);
2912 * sys_tgkill - send signal to one specific thread
2913 * @tgid: the thread group ID of the thread
2914 * @pid: the PID of the thread
2915 * @sig: signal to be sent
2917 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2918 * exists but it's not belonging to the target process anymore. This
2919 * method solves the problem of threads exiting and PIDs getting reused.
2921 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2923 /* This is only valid for single tasks */
2924 if (pid <= 0 || tgid <= 0)
2927 return do_tkill(tgid, pid, sig);
2931 * sys_tkill - send signal to one specific task
2932 * @pid: the PID of the task
2933 * @sig: signal to be sent
2935 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2937 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
2939 /* This is only valid for single tasks */
2943 return do_tkill(0, pid, sig);
2946 static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
2948 /* Not even root can pretend to send signals from the kernel.
2949 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2951 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
2952 (task_pid_vnr(current) != pid))
2955 info->si_signo = sig;
2957 /* POSIX.1b doesn't mention process groups. */
2958 return kill_proc_info(sig, info, pid);
2962 * sys_rt_sigqueueinfo - send signal information to a signal
2963 * @pid: the PID of the thread
2964 * @sig: signal to be sent
2965 * @uinfo: signal info to be sent
2967 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
2968 siginfo_t __user *, uinfo)
2971 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2973 return do_rt_sigqueueinfo(pid, sig, &info);
2976 #ifdef CONFIG_COMPAT
2977 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
2980 struct compat_siginfo __user *, uinfo)
2982 siginfo_t info = {};
2983 int ret = copy_siginfo_from_user32(&info, uinfo);
2986 return do_rt_sigqueueinfo(pid, sig, &info);
2990 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
2992 /* This is only valid for single tasks */
2993 if (pid <= 0 || tgid <= 0)
2996 /* Not even root can pretend to send signals from the kernel.
2997 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2999 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3000 (task_pid_vnr(current) != pid))
3003 info->si_signo = sig;
3005 return do_send_specific(tgid, pid, sig, info);
3008 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3009 siginfo_t __user *, uinfo)
3013 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3016 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3019 #ifdef CONFIG_COMPAT
3020 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3024 struct compat_siginfo __user *, uinfo)
3026 siginfo_t info = {};
3028 if (copy_siginfo_from_user32(&info, uinfo))
3030 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3035 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3037 void kernel_sigaction(int sig, __sighandler_t action)
3039 spin_lock_irq(¤t->sighand->siglock);
3040 current->sighand->action[sig - 1].sa.sa_handler = action;
3041 if (action == SIG_IGN) {
3045 sigaddset(&mask, sig);
3047 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3048 flush_sigqueue_mask(&mask, ¤t->pending);
3049 recalc_sigpending();
3051 spin_unlock_irq(¤t->sighand->siglock);
3053 EXPORT_SYMBOL(kernel_sigaction);
3055 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3057 struct task_struct *p = current, *t;
3058 struct k_sigaction *k;
3061 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3064 k = &p->sighand->action[sig-1];
3066 spin_lock_irq(&p->sighand->siglock);
3071 sigdelsetmask(&act->sa.sa_mask,
3072 sigmask(SIGKILL) | sigmask(SIGSTOP));
3076 * "Setting a signal action to SIG_IGN for a signal that is
3077 * pending shall cause the pending signal to be discarded,
3078 * whether or not it is blocked."
3080 * "Setting a signal action to SIG_DFL for a signal that is
3081 * pending and whose default action is to ignore the signal
3082 * (for example, SIGCHLD), shall cause the pending signal to
3083 * be discarded, whether or not it is blocked"
3085 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3087 sigaddset(&mask, sig);
3088 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3089 for_each_thread(p, t)
3090 flush_sigqueue_mask(&mask, &t->pending);
3094 spin_unlock_irq(&p->sighand->siglock);
3099 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
3104 oss.ss_sp = (void __user *) current->sas_ss_sp;
3105 oss.ss_size = current->sas_ss_size;
3106 oss.ss_flags = sas_ss_flags(sp);
3114 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
3116 error = __get_user(ss_sp, &uss->ss_sp) |
3117 __get_user(ss_flags, &uss->ss_flags) |
3118 __get_user(ss_size, &uss->ss_size);
3123 if (on_sig_stack(sp))
3128 * Note - this code used to test ss_flags incorrectly:
3129 * old code may have been written using ss_flags==0
3130 * to mean ss_flags==SS_ONSTACK (as this was the only
3131 * way that worked) - this fix preserves that older
3134 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
3137 if (ss_flags == SS_DISABLE) {
3142 if (ss_size < MINSIGSTKSZ)
3146 current->sas_ss_sp = (unsigned long) ss_sp;
3147 current->sas_ss_size = ss_size;
3153 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
3155 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
3156 __put_user(oss.ss_size, &uoss->ss_size) |
3157 __put_user(oss.ss_flags, &uoss->ss_flags);
3163 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3165 return do_sigaltstack(uss, uoss, current_user_stack_pointer());
3168 int restore_altstack(const stack_t __user *uss)
3170 int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
3171 /* squash all but EFAULT for now */
3172 return err == -EFAULT ? err : 0;
3175 int __save_altstack(stack_t __user *uss, unsigned long sp)
3177 struct task_struct *t = current;
3178 return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3179 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3180 __put_user(t->sas_ss_size, &uss->ss_size);
3183 #ifdef CONFIG_COMPAT
3184 COMPAT_SYSCALL_DEFINE2(sigaltstack,
3185 const compat_stack_t __user *, uss_ptr,
3186 compat_stack_t __user *, uoss_ptr)
3193 compat_stack_t uss32;
3195 memset(&uss, 0, sizeof(stack_t));
3196 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
3198 uss.ss_sp = compat_ptr(uss32.ss_sp);
3199 uss.ss_flags = uss32.ss_flags;
3200 uss.ss_size = uss32.ss_size;
3204 ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
3205 (stack_t __force __user *) &uoss,
3206 compat_user_stack_pointer());
3208 if (ret >= 0 && uoss_ptr) {
3209 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
3210 __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
3211 __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
3212 __put_user(uoss.ss_size, &uoss_ptr->ss_size))
3218 int compat_restore_altstack(const compat_stack_t __user *uss)
3220 int err = compat_sys_sigaltstack(uss, NULL);
3221 /* squash all but -EFAULT for now */
3222 return err == -EFAULT ? err : 0;
3225 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
3227 struct task_struct *t = current;
3228 return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
3229 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3230 __put_user(t->sas_ss_size, &uss->ss_size);
3234 #ifdef __ARCH_WANT_SYS_SIGPENDING
3237 * sys_sigpending - examine pending signals
3238 * @set: where mask of pending signal is returned
3240 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
3242 return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
3247 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3249 * sys_sigprocmask - examine and change blocked signals
3250 * @how: whether to add, remove, or set signals
3251 * @nset: signals to add or remove (if non-null)
3252 * @oset: previous value of signal mask if non-null
3254 * Some platforms have their own version with special arguments;
3255 * others support only sys_rt_sigprocmask.
3258 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
3259 old_sigset_t __user *, oset)
3261 old_sigset_t old_set, new_set;
3262 sigset_t new_blocked;
3264 old_set = current->blocked.sig[0];
3267 if (copy_from_user(&new_set, nset, sizeof(*nset)))
3270 new_blocked = current->blocked;
3274 sigaddsetmask(&new_blocked, new_set);
3277 sigdelsetmask(&new_blocked, new_set);
3280 new_blocked.sig[0] = new_set;
3286 set_current_blocked(&new_blocked);
3290 if (copy_to_user(oset, &old_set, sizeof(*oset)))
3296 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3298 #ifndef CONFIG_ODD_RT_SIGACTION
3300 * sys_rt_sigaction - alter an action taken by a process
3301 * @sig: signal to be sent
3302 * @act: new sigaction
3303 * @oact: used to save the previous sigaction
3304 * @sigsetsize: size of sigset_t type
3306 SYSCALL_DEFINE4(rt_sigaction, int, sig,
3307 const struct sigaction __user *, act,
3308 struct sigaction __user *, oact,
3311 struct k_sigaction new_sa, old_sa;
3314 /* XXX: Don't preclude handling different sized sigset_t's. */
3315 if (sigsetsize != sizeof(sigset_t))
3319 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
3323 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
3326 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
3332 #ifdef CONFIG_COMPAT
3333 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
3334 const struct compat_sigaction __user *, act,
3335 struct compat_sigaction __user *, oact,
3336 compat_size_t, sigsetsize)
3338 struct k_sigaction new_ka, old_ka;
3339 compat_sigset_t mask;
3340 #ifdef __ARCH_HAS_SA_RESTORER
3341 compat_uptr_t restorer;
3345 /* XXX: Don't preclude handling different sized sigset_t's. */
3346 if (sigsetsize != sizeof(compat_sigset_t))
3350 compat_uptr_t handler;
3351 ret = get_user(handler, &act->sa_handler);
3352 new_ka.sa.sa_handler = compat_ptr(handler);
3353 #ifdef __ARCH_HAS_SA_RESTORER
3354 ret |= get_user(restorer, &act->sa_restorer);
3355 new_ka.sa.sa_restorer = compat_ptr(restorer);
3357 ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
3358 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
3361 sigset_from_compat(&new_ka.sa.sa_mask, &mask);
3364 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3366 sigset_to_compat(&mask, &old_ka.sa.sa_mask);
3367 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
3369 ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
3370 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
3371 #ifdef __ARCH_HAS_SA_RESTORER
3372 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3373 &oact->sa_restorer);
3379 #endif /* !CONFIG_ODD_RT_SIGACTION */
3381 #ifdef CONFIG_OLD_SIGACTION
3382 SYSCALL_DEFINE3(sigaction, int, sig,
3383 const struct old_sigaction __user *, act,
3384 struct old_sigaction __user *, oact)
3386 struct k_sigaction new_ka, old_ka;
3391 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3392 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
3393 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
3394 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3395 __get_user(mask, &act->sa_mask))
3397 #ifdef __ARCH_HAS_KA_RESTORER
3398 new_ka.ka_restorer = NULL;
3400 siginitset(&new_ka.sa.sa_mask, mask);
3403 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3406 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3407 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
3408 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
3409 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3410 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3417 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3418 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
3419 const struct compat_old_sigaction __user *, act,
3420 struct compat_old_sigaction __user *, oact)
3422 struct k_sigaction new_ka, old_ka;
3424 compat_old_sigset_t mask;
3425 compat_uptr_t handler, restorer;
3428 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3429 __get_user(handler, &act->sa_handler) ||
3430 __get_user(restorer, &act->sa_restorer) ||
3431 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3432 __get_user(mask, &act->sa_mask))
3435 #ifdef __ARCH_HAS_KA_RESTORER
3436 new_ka.ka_restorer = NULL;
3438 new_ka.sa.sa_handler = compat_ptr(handler);
3439 new_ka.sa.sa_restorer = compat_ptr(restorer);
3440 siginitset(&new_ka.sa.sa_mask, mask);
3443 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3446 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3447 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
3448 &oact->sa_handler) ||
3449 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3450 &oact->sa_restorer) ||
3451 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3452 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3459 #ifdef CONFIG_SGETMASK_SYSCALL
3462 * For backwards compatibility. Functionality superseded by sigprocmask.
3464 SYSCALL_DEFINE0(sgetmask)
3467 return current->blocked.sig[0];
3470 SYSCALL_DEFINE1(ssetmask, int, newmask)
3472 int old = current->blocked.sig[0];
3475 siginitset(&newset, newmask);
3476 set_current_blocked(&newset);
3480 #endif /* CONFIG_SGETMASK_SYSCALL */
3482 #ifdef __ARCH_WANT_SYS_SIGNAL
3484 * For backwards compatibility. Functionality superseded by sigaction.
3486 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
3488 struct k_sigaction new_sa, old_sa;
3491 new_sa.sa.sa_handler = handler;
3492 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
3493 sigemptyset(&new_sa.sa.sa_mask);
3495 ret = do_sigaction(sig, &new_sa, &old_sa);
3497 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
3499 #endif /* __ARCH_WANT_SYS_SIGNAL */
3501 #ifdef __ARCH_WANT_SYS_PAUSE
3503 SYSCALL_DEFINE0(pause)
3505 while (!signal_pending(current)) {
3506 __set_current_state(TASK_INTERRUPTIBLE);
3509 return -ERESTARTNOHAND;
3514 static int sigsuspend(sigset_t *set)
3516 current->saved_sigmask = current->blocked;
3517 set_current_blocked(set);
3519 while (!signal_pending(current)) {
3520 __set_current_state(TASK_INTERRUPTIBLE);
3523 set_restore_sigmask();
3524 return -ERESTARTNOHAND;
3528 * sys_rt_sigsuspend - replace the signal mask for a value with the
3529 * @unewset value until a signal is received
3530 * @unewset: new signal mask value
3531 * @sigsetsize: size of sigset_t type
3533 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
3537 /* XXX: Don't preclude handling different sized sigset_t's. */
3538 if (sigsetsize != sizeof(sigset_t))
3541 if (copy_from_user(&newset, unewset, sizeof(newset)))
3543 return sigsuspend(&newset);
3546 #ifdef CONFIG_COMPAT
3547 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
3551 compat_sigset_t newset32;
3553 /* XXX: Don't preclude handling different sized sigset_t's. */
3554 if (sigsetsize != sizeof(sigset_t))
3557 if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
3559 sigset_from_compat(&newset, &newset32);
3560 return sigsuspend(&newset);
3562 /* on little-endian bitmaps don't care about granularity */
3563 return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize);
3568 #ifdef CONFIG_OLD_SIGSUSPEND
3569 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
3572 siginitset(&blocked, mask);
3573 return sigsuspend(&blocked);
3576 #ifdef CONFIG_OLD_SIGSUSPEND3
3577 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
3580 siginitset(&blocked, mask);
3581 return sigsuspend(&blocked);
3585 __weak const char *arch_vma_name(struct vm_area_struct *vma)
3590 void __init signals_init(void)
3592 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
3595 #ifdef CONFIG_KGDB_KDB
3596 #include <linux/kdb.h>
3598 * kdb_send_sig_info - Allows kdb to send signals without exposing
3599 * signal internals. This function checks if the required locks are
3600 * available before calling the main signal code, to avoid kdb
3604 kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
3606 static struct task_struct *kdb_prev_t;
3608 if (!spin_trylock(&t->sighand->siglock)) {
3609 kdb_printf("Can't do kill command now.\n"
3610 "The sigmask lock is held somewhere else in "
3611 "kernel, try again later\n");
3614 spin_unlock(&t->sighand->siglock);
3615 new_t = kdb_prev_t != t;
3617 if (t->state != TASK_RUNNING && new_t) {
3618 kdb_printf("Process is not RUNNING, sending a signal from "
3619 "kdb risks deadlock\n"
3620 "on the run queue locks. "
3621 "The signal has _not_ been sent.\n"
3622 "Reissue the kill command if you want to risk "
3626 sig = info->si_signo;
3627 if (send_sig_info(sig, info, t))
3628 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3631 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
3633 #endif /* CONFIG_KGDB_KDB */