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/mm.h>
17 #include <linux/sched/user.h>
18 #include <linux/sched/debug.h>
19 #include <linux/sched/task.h>
20 #include <linux/sched/task_stack.h>
22 #include <linux/tty.h>
23 #include <linux/binfmts.h>
24 #include <linux/coredump.h>
25 #include <linux/security.h>
26 #include <linux/syscalls.h>
27 #include <linux/ptrace.h>
28 #include <linux/signal.h>
29 #include <linux/signalfd.h>
30 #include <linux/ratelimit.h>
31 #include <linux/tracehook.h>
32 #include <linux/capability.h>
33 #include <linux/freezer.h>
34 #include <linux/pid_namespace.h>
35 #include <linux/nsproxy.h>
36 #include <linux/user_namespace.h>
37 #include <linux/uprobes.h>
38 #include <linux/compat.h>
39 #include <linux/cn_proc.h>
40 #include <linux/compiler.h>
42 #define CREATE_TRACE_POINTS
43 #include <trace/events/signal.h>
45 #include <asm/param.h>
46 #include <linux/uaccess.h>
47 #include <asm/unistd.h>
48 #include <asm/siginfo.h>
49 #include <asm/cacheflush.h>
50 #include "audit.h" /* audit_signal_info() */
53 * SLAB caches for signal bits.
56 static struct kmem_cache *sigqueue_cachep;
58 int print_fatal_signals __read_mostly;
60 static void __user *sig_handler(struct task_struct *t, int sig)
62 return t->sighand->action[sig - 1].sa.sa_handler;
65 static int sig_handler_ignored(void __user *handler, int sig)
67 /* Is it explicitly or implicitly ignored? */
68 return handler == SIG_IGN ||
69 (handler == SIG_DFL && sig_kernel_ignore(sig));
72 static int sig_task_ignored(struct task_struct *t, int sig, bool force)
76 handler = sig_handler(t, sig);
78 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
79 handler == SIG_DFL && !force)
82 return sig_handler_ignored(handler, sig);
85 static int sig_ignored(struct task_struct *t, int sig, bool force)
88 * Blocked signals are never ignored, since the
89 * signal handler may change by the time it is
92 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
95 if (!sig_task_ignored(t, sig, force))
99 * Tracers may want to know about even ignored signals.
105 * Re-calculate pending state from the set of locally pending
106 * signals, globally pending signals, and blocked signals.
108 static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
113 switch (_NSIG_WORDS) {
115 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
116 ready |= signal->sig[i] &~ blocked->sig[i];
119 case 4: ready = signal->sig[3] &~ blocked->sig[3];
120 ready |= signal->sig[2] &~ blocked->sig[2];
121 ready |= signal->sig[1] &~ blocked->sig[1];
122 ready |= signal->sig[0] &~ blocked->sig[0];
125 case 2: ready = signal->sig[1] &~ blocked->sig[1];
126 ready |= signal->sig[0] &~ blocked->sig[0];
129 case 1: ready = signal->sig[0] &~ blocked->sig[0];
134 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
136 static int recalc_sigpending_tsk(struct task_struct *t)
138 if ((t->jobctl & JOBCTL_PENDING_MASK) ||
139 PENDING(&t->pending, &t->blocked) ||
140 PENDING(&t->signal->shared_pending, &t->blocked)) {
141 set_tsk_thread_flag(t, TIF_SIGPENDING);
145 * We must never clear the flag in another thread, or in current
146 * when it's possible the current syscall is returning -ERESTART*.
147 * So we don't clear it here, and only callers who know they should do.
153 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
154 * This is superfluous when called on current, the wakeup is a harmless no-op.
156 void recalc_sigpending_and_wake(struct task_struct *t)
158 if (recalc_sigpending_tsk(t))
159 signal_wake_up(t, 0);
162 void recalc_sigpending(void)
164 if (!recalc_sigpending_tsk(current) && !freezing(current))
165 clear_thread_flag(TIF_SIGPENDING);
169 /* Given the mask, find the first available signal that should be serviced. */
171 #define SYNCHRONOUS_MASK \
172 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
173 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
175 int next_signal(struct sigpending *pending, sigset_t *mask)
177 unsigned long i, *s, *m, x;
180 s = pending->signal.sig;
184 * Handle the first word specially: it contains the
185 * synchronous signals that need to be dequeued first.
189 if (x & SYNCHRONOUS_MASK)
190 x &= SYNCHRONOUS_MASK;
195 switch (_NSIG_WORDS) {
197 for (i = 1; i < _NSIG_WORDS; ++i) {
201 sig = ffz(~x) + i*_NSIG_BPW + 1;
210 sig = ffz(~x) + _NSIG_BPW + 1;
221 static inline void print_dropped_signal(int sig)
223 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
225 if (!print_fatal_signals)
228 if (!__ratelimit(&ratelimit_state))
231 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
232 current->comm, current->pid, sig);
236 * task_set_jobctl_pending - set jobctl pending bits
238 * @mask: pending bits to set
240 * Clear @mask from @task->jobctl. @mask must be subset of
241 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
242 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
243 * cleared. If @task is already being killed or exiting, this function
247 * Must be called with @task->sighand->siglock held.
250 * %true if @mask is set, %false if made noop because @task was dying.
252 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
254 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
255 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
256 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
258 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
261 if (mask & JOBCTL_STOP_SIGMASK)
262 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
264 task->jobctl |= mask;
269 * task_clear_jobctl_trapping - clear jobctl trapping bit
272 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
273 * Clear it and wake up the ptracer. Note that we don't need any further
274 * locking. @task->siglock guarantees that @task->parent points to the
278 * Must be called with @task->sighand->siglock held.
280 void task_clear_jobctl_trapping(struct task_struct *task)
282 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
283 task->jobctl &= ~JOBCTL_TRAPPING;
284 smp_mb(); /* advised by wake_up_bit() */
285 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
290 * task_clear_jobctl_pending - clear jobctl pending bits
292 * @mask: pending bits to clear
294 * Clear @mask from @task->jobctl. @mask must be subset of
295 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
296 * STOP bits are cleared together.
298 * If clearing of @mask leaves no stop or trap pending, this function calls
299 * task_clear_jobctl_trapping().
302 * Must be called with @task->sighand->siglock held.
304 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
306 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
308 if (mask & JOBCTL_STOP_PENDING)
309 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
311 task->jobctl &= ~mask;
313 if (!(task->jobctl & JOBCTL_PENDING_MASK))
314 task_clear_jobctl_trapping(task);
318 * task_participate_group_stop - participate in a group stop
319 * @task: task participating in a group stop
321 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
322 * Group stop states are cleared and the group stop count is consumed if
323 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
324 * stop, the appropriate %SIGNAL_* flags are set.
327 * Must be called with @task->sighand->siglock held.
330 * %true if group stop completion should be notified to the parent, %false
333 static bool task_participate_group_stop(struct task_struct *task)
335 struct signal_struct *sig = task->signal;
336 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
338 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
340 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
345 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
346 sig->group_stop_count--;
349 * Tell the caller to notify completion iff we are entering into a
350 * fresh group stop. Read comment in do_signal_stop() for details.
352 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
353 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
360 * allocate a new signal queue record
361 * - this may be called without locks if and only if t == current, otherwise an
362 * appropriate lock must be held to stop the target task from exiting
364 static struct sigqueue *
365 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
367 struct sigqueue *q = NULL;
368 struct user_struct *user;
371 * Protect access to @t credentials. This can go away when all
372 * callers hold rcu read lock.
375 user = get_uid(__task_cred(t)->user);
376 atomic_inc(&user->sigpending);
379 if (override_rlimit ||
380 atomic_read(&user->sigpending) <=
381 task_rlimit(t, RLIMIT_SIGPENDING)) {
382 q = kmem_cache_alloc(sigqueue_cachep, flags);
384 print_dropped_signal(sig);
387 if (unlikely(q == NULL)) {
388 atomic_dec(&user->sigpending);
391 INIT_LIST_HEAD(&q->list);
399 static void __sigqueue_free(struct sigqueue *q)
401 if (q->flags & SIGQUEUE_PREALLOC)
403 atomic_dec(&q->user->sigpending);
405 kmem_cache_free(sigqueue_cachep, q);
408 void flush_sigqueue(struct sigpending *queue)
412 sigemptyset(&queue->signal);
413 while (!list_empty(&queue->list)) {
414 q = list_entry(queue->list.next, struct sigqueue , list);
415 list_del_init(&q->list);
421 * Flush all pending signals for this kthread.
423 void flush_signals(struct task_struct *t)
427 spin_lock_irqsave(&t->sighand->siglock, flags);
428 clear_tsk_thread_flag(t, TIF_SIGPENDING);
429 flush_sigqueue(&t->pending);
430 flush_sigqueue(&t->signal->shared_pending);
431 spin_unlock_irqrestore(&t->sighand->siglock, flags);
434 #ifdef CONFIG_POSIX_TIMERS
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);
470 void ignore_signals(struct task_struct *t)
474 for (i = 0; i < _NSIG; ++i)
475 t->sighand->action[i].sa.sa_handler = SIG_IGN;
481 * Flush all handlers for a task.
485 flush_signal_handlers(struct task_struct *t, int force_default)
488 struct k_sigaction *ka = &t->sighand->action[0];
489 for (i = _NSIG ; i != 0 ; i--) {
490 if (force_default || ka->sa.sa_handler != SIG_IGN)
491 ka->sa.sa_handler = SIG_DFL;
493 #ifdef __ARCH_HAS_SA_RESTORER
494 ka->sa.sa_restorer = NULL;
496 sigemptyset(&ka->sa.sa_mask);
501 int unhandled_signal(struct task_struct *tsk, int sig)
503 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
504 if (is_global_init(tsk))
506 if (handler != SIG_IGN && handler != SIG_DFL)
508 /* if ptraced, let the tracer determine */
512 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
514 struct sigqueue *q, *first = NULL;
517 * Collect the siginfo appropriate to this signal. Check if
518 * there is another siginfo for the same signal.
520 list_for_each_entry(q, &list->list, list) {
521 if (q->info.si_signo == sig) {
528 sigdelset(&list->signal, sig);
532 list_del_init(&first->list);
533 copy_siginfo(info, &first->info);
534 __sigqueue_free(first);
537 * Ok, it wasn't in the queue. This must be
538 * a fast-pathed signal or we must have been
539 * out of queue space. So zero out the info.
541 info->si_signo = sig;
543 info->si_code = SI_USER;
549 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
552 int sig = next_signal(pending, mask);
555 collect_signal(sig, pending, info);
560 * Dequeue a signal and return the element to the caller, which is
561 * expected to free it.
563 * All callers have to hold the siglock.
565 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
569 /* We only dequeue private signals from ourselves, we don't let
570 * signalfd steal them
572 signr = __dequeue_signal(&tsk->pending, mask, info);
574 signr = __dequeue_signal(&tsk->signal->shared_pending,
576 #ifdef CONFIG_POSIX_TIMERS
580 * itimers are process shared and we restart periodic
581 * itimers in the signal delivery path to prevent DoS
582 * attacks in the high resolution timer case. This is
583 * compliant with the old way of self-restarting
584 * itimers, as the SIGALRM is a legacy signal and only
585 * queued once. Changing the restart behaviour to
586 * restart the timer in the signal dequeue path is
587 * reducing the timer noise on heavy loaded !highres
590 if (unlikely(signr == SIGALRM)) {
591 struct hrtimer *tmr = &tsk->signal->real_timer;
593 if (!hrtimer_is_queued(tmr) &&
594 tsk->signal->it_real_incr != 0) {
595 hrtimer_forward(tmr, tmr->base->get_time(),
596 tsk->signal->it_real_incr);
597 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;
622 #ifdef CONFIG_POSIX_TIMERS
623 if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
625 * Release the siglock to ensure proper locking order
626 * of timer locks outside of siglocks. Note, we leave
627 * irqs disabled here, since the posix-timers code is
628 * about to disable them again anyway.
630 spin_unlock(&tsk->sighand->siglock);
631 do_schedule_next_timer(info);
632 spin_lock(&tsk->sighand->siglock);
639 * Tell a process that it has a new active signal..
641 * NOTE! we rely on the previous spin_lock to
642 * lock interrupts for us! We can only be called with
643 * "siglock" held, and the local interrupt must
644 * have been disabled when that got acquired!
646 * No need to set need_resched since signal event passing
647 * goes through ->blocked
649 void signal_wake_up_state(struct task_struct *t, unsigned int state)
651 set_tsk_thread_flag(t, TIF_SIGPENDING);
653 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
654 * case. We don't check t->state here because there is a race with it
655 * executing another processor and just now entering stopped state.
656 * By using wake_up_state, we ensure the process will wake up and
657 * handle its death signal.
659 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
664 * Remove signals in mask from the pending set and queue.
665 * Returns 1 if any signals were found.
667 * All callers must be holding the siglock.
669 static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
671 struct sigqueue *q, *n;
674 sigandsets(&m, mask, &s->signal);
675 if (sigisemptyset(&m))
678 sigandnsets(&s->signal, &s->signal, mask);
679 list_for_each_entry_safe(q, n, &s->list, list) {
680 if (sigismember(mask, q->info.si_signo)) {
681 list_del_init(&q->list);
688 static inline int is_si_special(const struct siginfo *info)
690 return info <= SEND_SIG_FORCED;
693 static inline bool si_fromuser(const struct siginfo *info)
695 return info == SEND_SIG_NOINFO ||
696 (!is_si_special(info) && SI_FROMUSER(info));
700 * called with RCU read lock from check_kill_permission()
702 static int kill_ok_by_cred(struct task_struct *t)
704 const struct cred *cred = current_cred();
705 const struct cred *tcred = __task_cred(t);
707 if (uid_eq(cred->euid, tcred->suid) ||
708 uid_eq(cred->euid, tcred->uid) ||
709 uid_eq(cred->uid, tcred->suid) ||
710 uid_eq(cred->uid, tcred->uid))
713 if (ns_capable(tcred->user_ns, CAP_KILL))
720 * Bad permissions for sending the signal
721 * - the caller must hold the RCU read lock
723 static int check_kill_permission(int sig, struct siginfo *info,
724 struct task_struct *t)
729 if (!valid_signal(sig))
732 if (!si_fromuser(info))
735 error = audit_signal_info(sig, t); /* Let audit system see the signal */
739 if (!same_thread_group(current, t) &&
740 !kill_ok_by_cred(t)) {
743 sid = task_session(t);
745 * We don't return the error if sid == NULL. The
746 * task was unhashed, the caller must notice this.
748 if (!sid || sid == task_session(current))
755 return security_task_kill(t, info, sig, 0);
759 * ptrace_trap_notify - schedule trap to notify ptracer
760 * @t: tracee wanting to notify tracer
762 * This function schedules sticky ptrace trap which is cleared on the next
763 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
766 * If @t is running, STOP trap will be taken. If trapped for STOP and
767 * ptracer is listening for events, tracee is woken up so that it can
768 * re-trap for the new event. If trapped otherwise, STOP trap will be
769 * eventually taken without returning to userland after the existing traps
770 * are finished by PTRACE_CONT.
773 * Must be called with @task->sighand->siglock held.
775 static void ptrace_trap_notify(struct task_struct *t)
777 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
778 assert_spin_locked(&t->sighand->siglock);
780 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
781 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
785 * Handle magic process-wide effects of stop/continue signals. Unlike
786 * the signal actions, these happen immediately at signal-generation
787 * time regardless of blocking, ignoring, or handling. This does the
788 * actual continuing for SIGCONT, but not the actual stopping for stop
789 * signals. The process stop is done as a signal action for SIG_DFL.
791 * Returns true if the signal should be actually delivered, otherwise
792 * it should be dropped.
794 static bool prepare_signal(int sig, struct task_struct *p, bool force)
796 struct signal_struct *signal = p->signal;
797 struct task_struct *t;
800 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
801 if (!(signal->flags & SIGNAL_GROUP_EXIT))
802 return sig == SIGKILL;
804 * The process is in the middle of dying, nothing to do.
806 } else if (sig_kernel_stop(sig)) {
808 * This is a stop signal. Remove SIGCONT from all queues.
810 siginitset(&flush, sigmask(SIGCONT));
811 flush_sigqueue_mask(&flush, &signal->shared_pending);
812 for_each_thread(p, t)
813 flush_sigqueue_mask(&flush, &t->pending);
814 } else if (sig == SIGCONT) {
817 * Remove all stop signals from all queues, wake all threads.
819 siginitset(&flush, SIG_KERNEL_STOP_MASK);
820 flush_sigqueue_mask(&flush, &signal->shared_pending);
821 for_each_thread(p, t) {
822 flush_sigqueue_mask(&flush, &t->pending);
823 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
824 if (likely(!(t->ptrace & PT_SEIZED)))
825 wake_up_state(t, __TASK_STOPPED);
827 ptrace_trap_notify(t);
831 * Notify the parent with CLD_CONTINUED if we were stopped.
833 * If we were in the middle of a group stop, we pretend it
834 * was already finished, and then continued. Since SIGCHLD
835 * doesn't queue we report only CLD_STOPPED, as if the next
836 * CLD_CONTINUED was dropped.
839 if (signal->flags & SIGNAL_STOP_STOPPED)
840 why |= SIGNAL_CLD_CONTINUED;
841 else if (signal->group_stop_count)
842 why |= SIGNAL_CLD_STOPPED;
846 * The first thread which returns from do_signal_stop()
847 * will take ->siglock, notice SIGNAL_CLD_MASK, and
848 * notify its parent. See get_signal_to_deliver().
850 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
851 signal->group_stop_count = 0;
852 signal->group_exit_code = 0;
856 return !sig_ignored(p, sig, force);
860 * Test if P wants to take SIG. After we've checked all threads with this,
861 * it's equivalent to finding no threads not blocking SIG. Any threads not
862 * blocking SIG were ruled out because they are not running and already
863 * have pending signals. Such threads will dequeue from the shared queue
864 * as soon as they're available, so putting the signal on the shared queue
865 * will be equivalent to sending it to one such thread.
867 static inline int wants_signal(int sig, struct task_struct *p)
869 if (sigismember(&p->blocked, sig))
871 if (p->flags & PF_EXITING)
875 if (task_is_stopped_or_traced(p))
877 return task_curr(p) || !signal_pending(p);
880 static void complete_signal(int sig, struct task_struct *p, int group)
882 struct signal_struct *signal = p->signal;
883 struct task_struct *t;
886 * Now find a thread we can wake up to take the signal off the queue.
888 * If the main thread wants the signal, it gets first crack.
889 * Probably the least surprising to the average bear.
891 if (wants_signal(sig, p))
893 else if (!group || thread_group_empty(p))
895 * There is just one thread and it does not need to be woken.
896 * It will dequeue unblocked signals before it runs again.
901 * Otherwise try to find a suitable thread.
903 t = signal->curr_target;
904 while (!wants_signal(sig, t)) {
906 if (t == signal->curr_target)
908 * No thread needs to be woken.
909 * Any eligible threads will see
910 * the signal in the queue soon.
914 signal->curr_target = t;
918 * Found a killable thread. If the signal will be fatal,
919 * then start taking the whole group down immediately.
921 if (sig_fatal(p, sig) &&
922 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
923 !sigismember(&t->real_blocked, sig) &&
924 (sig == SIGKILL || !t->ptrace)) {
926 * This signal will be fatal to the whole group.
928 if (!sig_kernel_coredump(sig)) {
930 * Start a group exit and wake everybody up.
931 * This way we don't have other threads
932 * running and doing things after a slower
933 * thread has the fatal signal pending.
935 signal->flags = SIGNAL_GROUP_EXIT;
936 signal->group_exit_code = sig;
937 signal->group_stop_count = 0;
940 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
941 sigaddset(&t->pending.signal, SIGKILL);
942 signal_wake_up(t, 1);
943 } while_each_thread(p, t);
949 * The signal is already in the shared-pending queue.
950 * Tell the chosen thread to wake up and dequeue it.
952 signal_wake_up(t, sig == SIGKILL);
956 static inline int legacy_queue(struct sigpending *signals, int sig)
958 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
961 #ifdef CONFIG_USER_NS
962 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
964 if (current_user_ns() == task_cred_xxx(t, user_ns))
967 if (SI_FROMKERNEL(info))
971 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
972 make_kuid(current_user_ns(), info->si_uid));
976 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
982 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
983 int group, int from_ancestor_ns)
985 struct sigpending *pending;
990 assert_spin_locked(&t->sighand->siglock);
992 result = TRACE_SIGNAL_IGNORED;
993 if (!prepare_signal(sig, t,
994 from_ancestor_ns || (info == SEND_SIG_FORCED)))
997 pending = group ? &t->signal->shared_pending : &t->pending;
999 * Short-circuit ignored signals and support queuing
1000 * exactly one non-rt signal, so that we can get more
1001 * detailed information about the cause of the signal.
1003 result = TRACE_SIGNAL_ALREADY_PENDING;
1004 if (legacy_queue(pending, sig))
1007 result = TRACE_SIGNAL_DELIVERED;
1009 * fast-pathed signals for kernel-internal things like SIGSTOP
1012 if (info == SEND_SIG_FORCED)
1016 * Real-time signals must be queued if sent by sigqueue, or
1017 * some other real-time mechanism. It is implementation
1018 * defined whether kill() does so. We attempt to do so, on
1019 * the principle of least surprise, but since kill is not
1020 * allowed to fail with EAGAIN when low on memory we just
1021 * make sure at least one signal gets delivered and don't
1022 * pass on the info struct.
1025 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1027 override_rlimit = 0;
1029 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
1032 list_add_tail(&q->list, &pending->list);
1033 switch ((unsigned long) info) {
1034 case (unsigned long) SEND_SIG_NOINFO:
1035 q->info.si_signo = sig;
1036 q->info.si_errno = 0;
1037 q->info.si_code = SI_USER;
1038 q->info.si_pid = task_tgid_nr_ns(current,
1039 task_active_pid_ns(t));
1040 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1042 case (unsigned long) SEND_SIG_PRIV:
1043 q->info.si_signo = sig;
1044 q->info.si_errno = 0;
1045 q->info.si_code = SI_KERNEL;
1050 copy_siginfo(&q->info, info);
1051 if (from_ancestor_ns)
1056 userns_fixup_signal_uid(&q->info, t);
1058 } else if (!is_si_special(info)) {
1059 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1061 * Queue overflow, abort. We may abort if the
1062 * signal was rt and sent by user using something
1063 * other than kill().
1065 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1070 * This is a silent loss of information. We still
1071 * send the signal, but the *info bits are lost.
1073 result = TRACE_SIGNAL_LOSE_INFO;
1078 signalfd_notify(t, sig);
1079 sigaddset(&pending->signal, sig);
1080 complete_signal(sig, t, group);
1082 trace_signal_generate(sig, info, t, group, result);
1086 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
1089 int from_ancestor_ns = 0;
1091 #ifdef CONFIG_PID_NS
1092 from_ancestor_ns = si_fromuser(info) &&
1093 !task_pid_nr_ns(current, task_active_pid_ns(t));
1096 return __send_signal(sig, info, t, group, from_ancestor_ns);
1099 static void print_fatal_signal(int signr)
1101 struct pt_regs *regs = signal_pt_regs();
1102 pr_info("potentially unexpected fatal signal %d.\n", signr);
1104 #if defined(__i386__) && !defined(__arch_um__)
1105 pr_info("code at %08lx: ", regs->ip);
1108 for (i = 0; i < 16; i++) {
1111 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1113 pr_cont("%02x ", insn);
1123 static int __init setup_print_fatal_signals(char *str)
1125 get_option (&str, &print_fatal_signals);
1130 __setup("print-fatal-signals=", setup_print_fatal_signals);
1133 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1135 return send_signal(sig, info, p, 1);
1139 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1141 return send_signal(sig, info, t, 0);
1144 int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1147 unsigned long flags;
1150 if (lock_task_sighand(p, &flags)) {
1151 ret = send_signal(sig, info, p, group);
1152 unlock_task_sighand(p, &flags);
1159 * Force a signal that the process can't ignore: if necessary
1160 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1162 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1163 * since we do not want to have a signal handler that was blocked
1164 * be invoked when user space had explicitly blocked it.
1166 * We don't want to have recursive SIGSEGV's etc, for example,
1167 * that is why we also clear SIGNAL_UNKILLABLE.
1170 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1172 unsigned long int flags;
1173 int ret, blocked, ignored;
1174 struct k_sigaction *action;
1176 spin_lock_irqsave(&t->sighand->siglock, flags);
1177 action = &t->sighand->action[sig-1];
1178 ignored = action->sa.sa_handler == SIG_IGN;
1179 blocked = sigismember(&t->blocked, sig);
1180 if (blocked || ignored) {
1181 action->sa.sa_handler = SIG_DFL;
1183 sigdelset(&t->blocked, sig);
1184 recalc_sigpending_and_wake(t);
1187 if (action->sa.sa_handler == SIG_DFL)
1188 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1189 ret = specific_send_sig_info(sig, info, t);
1190 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1196 * Nuke all other threads in the group.
1198 int zap_other_threads(struct task_struct *p)
1200 struct task_struct *t = p;
1203 p->signal->group_stop_count = 0;
1205 while_each_thread(p, t) {
1206 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1209 /* Don't bother with already dead threads */
1212 sigaddset(&t->pending.signal, SIGKILL);
1213 signal_wake_up(t, 1);
1219 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1220 unsigned long *flags)
1222 struct sighand_struct *sighand;
1226 * Disable interrupts early to avoid deadlocks.
1227 * See rcu_read_unlock() comment header for details.
1229 local_irq_save(*flags);
1231 sighand = rcu_dereference(tsk->sighand);
1232 if (unlikely(sighand == NULL)) {
1234 local_irq_restore(*flags);
1238 * This sighand can be already freed and even reused, but
1239 * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which
1240 * initializes ->siglock: this slab can't go away, it has
1241 * the same object type, ->siglock can't be reinitialized.
1243 * We need to ensure that tsk->sighand is still the same
1244 * after we take the lock, we can race with de_thread() or
1245 * __exit_signal(). In the latter case the next iteration
1246 * must see ->sighand == NULL.
1248 spin_lock(&sighand->siglock);
1249 if (likely(sighand == tsk->sighand)) {
1253 spin_unlock(&sighand->siglock);
1255 local_irq_restore(*flags);
1262 * send signal info to all the members of a group
1264 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1269 ret = check_kill_permission(sig, info, p);
1273 ret = do_send_sig_info(sig, info, p, true);
1279 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1280 * control characters do (^C, ^Z etc)
1281 * - the caller must hold at least a readlock on tasklist_lock
1283 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1285 struct task_struct *p = NULL;
1286 int retval, success;
1290 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1291 int err = group_send_sig_info(sig, info, p);
1294 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1295 return success ? 0 : retval;
1298 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1301 struct task_struct *p;
1305 p = pid_task(pid, PIDTYPE_PID);
1307 error = group_send_sig_info(sig, info, p);
1309 if (likely(!p || error != -ESRCH))
1313 * The task was unhashed in between, try again. If it
1314 * is dead, pid_task() will return NULL, if we race with
1315 * de_thread() it will find the new leader.
1320 int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1324 error = kill_pid_info(sig, info, find_vpid(pid));
1329 static int kill_as_cred_perm(const struct cred *cred,
1330 struct task_struct *target)
1332 const struct cred *pcred = __task_cred(target);
1333 if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
1334 !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid))
1339 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1340 int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
1341 const struct cred *cred, u32 secid)
1344 struct task_struct *p;
1345 unsigned long flags;
1347 if (!valid_signal(sig))
1351 p = pid_task(pid, PIDTYPE_PID);
1356 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
1360 ret = security_task_kill(p, info, sig, secid);
1365 if (lock_task_sighand(p, &flags)) {
1366 ret = __send_signal(sig, info, p, 1, 0);
1367 unlock_task_sighand(p, &flags);
1375 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
1378 * kill_something_info() interprets pid in interesting ways just like kill(2).
1380 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1381 * is probably wrong. Should make it like BSD or SYSV.
1384 static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
1390 ret = kill_pid_info(sig, info, find_vpid(pid));
1395 read_lock(&tasklist_lock);
1397 ret = __kill_pgrp_info(sig, info,
1398 pid ? find_vpid(-pid) : task_pgrp(current));
1400 int retval = 0, count = 0;
1401 struct task_struct * p;
1403 for_each_process(p) {
1404 if (task_pid_vnr(p) > 1 &&
1405 !same_thread_group(p, current)) {
1406 int err = group_send_sig_info(sig, info, p);
1412 ret = count ? retval : -ESRCH;
1414 read_unlock(&tasklist_lock);
1420 * These are for backward compatibility with the rest of the kernel source.
1423 int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1426 * Make sure legacy kernel users don't send in bad values
1427 * (normal paths check this in check_kill_permission).
1429 if (!valid_signal(sig))
1432 return do_send_sig_info(sig, info, p, false);
1435 #define __si_special(priv) \
1436 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1439 send_sig(int sig, struct task_struct *p, int priv)
1441 return send_sig_info(sig, __si_special(priv), p);
1445 force_sig(int sig, struct task_struct *p)
1447 force_sig_info(sig, SEND_SIG_PRIV, p);
1451 * When things go south during signal handling, we
1452 * will force a SIGSEGV. And if the signal that caused
1453 * the problem was already a SIGSEGV, we'll want to
1454 * make sure we don't even try to deliver the signal..
1457 force_sigsegv(int sig, struct task_struct *p)
1459 if (sig == SIGSEGV) {
1460 unsigned long flags;
1461 spin_lock_irqsave(&p->sighand->siglock, flags);
1462 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1463 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1465 force_sig(SIGSEGV, p);
1469 int kill_pgrp(struct pid *pid, int sig, int priv)
1473 read_lock(&tasklist_lock);
1474 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1475 read_unlock(&tasklist_lock);
1479 EXPORT_SYMBOL(kill_pgrp);
1481 int kill_pid(struct pid *pid, int sig, int priv)
1483 return kill_pid_info(sig, __si_special(priv), pid);
1485 EXPORT_SYMBOL(kill_pid);
1488 * These functions support sending signals using preallocated sigqueue
1489 * structures. This is needed "because realtime applications cannot
1490 * afford to lose notifications of asynchronous events, like timer
1491 * expirations or I/O completions". In the case of POSIX Timers
1492 * we allocate the sigqueue structure from the timer_create. If this
1493 * allocation fails we are able to report the failure to the application
1494 * with an EAGAIN error.
1496 struct sigqueue *sigqueue_alloc(void)
1498 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1501 q->flags |= SIGQUEUE_PREALLOC;
1506 void sigqueue_free(struct sigqueue *q)
1508 unsigned long flags;
1509 spinlock_t *lock = ¤t->sighand->siglock;
1511 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1513 * We must hold ->siglock while testing q->list
1514 * to serialize with collect_signal() or with
1515 * __exit_signal()->flush_sigqueue().
1517 spin_lock_irqsave(lock, flags);
1518 q->flags &= ~SIGQUEUE_PREALLOC;
1520 * If it is queued it will be freed when dequeued,
1521 * like the "regular" sigqueue.
1523 if (!list_empty(&q->list))
1525 spin_unlock_irqrestore(lock, flags);
1531 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1533 int sig = q->info.si_signo;
1534 struct sigpending *pending;
1535 unsigned long flags;
1538 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1541 if (!likely(lock_task_sighand(t, &flags)))
1544 ret = 1; /* the signal is ignored */
1545 result = TRACE_SIGNAL_IGNORED;
1546 if (!prepare_signal(sig, t, false))
1550 if (unlikely(!list_empty(&q->list))) {
1552 * If an SI_TIMER entry is already queue just increment
1553 * the overrun count.
1555 BUG_ON(q->info.si_code != SI_TIMER);
1556 q->info.si_overrun++;
1557 result = TRACE_SIGNAL_ALREADY_PENDING;
1560 q->info.si_overrun = 0;
1562 signalfd_notify(t, sig);
1563 pending = group ? &t->signal->shared_pending : &t->pending;
1564 list_add_tail(&q->list, &pending->list);
1565 sigaddset(&pending->signal, sig);
1566 complete_signal(sig, t, group);
1567 result = TRACE_SIGNAL_DELIVERED;
1569 trace_signal_generate(sig, &q->info, t, group, result);
1570 unlock_task_sighand(t, &flags);
1576 * Let a parent know about the death of a child.
1577 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1579 * Returns true if our parent ignored us and so we've switched to
1582 bool do_notify_parent(struct task_struct *tsk, int sig)
1584 struct siginfo info;
1585 unsigned long flags;
1586 struct sighand_struct *psig;
1587 bool autoreap = false;
1592 /* do_notify_parent_cldstop should have been called instead. */
1593 BUG_ON(task_is_stopped_or_traced(tsk));
1595 BUG_ON(!tsk->ptrace &&
1596 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1598 if (sig != SIGCHLD) {
1600 * This is only possible if parent == real_parent.
1601 * Check if it has changed security domain.
1603 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1607 info.si_signo = sig;
1610 * We are under tasklist_lock here so our parent is tied to
1611 * us and cannot change.
1613 * task_active_pid_ns will always return the same pid namespace
1614 * until a task passes through release_task.
1616 * write_lock() currently calls preempt_disable() which is the
1617 * same as rcu_read_lock(), but according to Oleg, this is not
1618 * correct to rely on this
1621 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1622 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1626 task_cputime(tsk, &utime, &stime);
1627 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1628 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1630 info.si_status = tsk->exit_code & 0x7f;
1631 if (tsk->exit_code & 0x80)
1632 info.si_code = CLD_DUMPED;
1633 else if (tsk->exit_code & 0x7f)
1634 info.si_code = CLD_KILLED;
1636 info.si_code = CLD_EXITED;
1637 info.si_status = tsk->exit_code >> 8;
1640 psig = tsk->parent->sighand;
1641 spin_lock_irqsave(&psig->siglock, flags);
1642 if (!tsk->ptrace && sig == SIGCHLD &&
1643 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1644 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1646 * We are exiting and our parent doesn't care. POSIX.1
1647 * defines special semantics for setting SIGCHLD to SIG_IGN
1648 * or setting the SA_NOCLDWAIT flag: we should be reaped
1649 * automatically and not left for our parent's wait4 call.
1650 * Rather than having the parent do it as a magic kind of
1651 * signal handler, we just set this to tell do_exit that we
1652 * can be cleaned up without becoming a zombie. Note that
1653 * we still call __wake_up_parent in this case, because a
1654 * blocked sys_wait4 might now return -ECHILD.
1656 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1657 * is implementation-defined: we do (if you don't want
1658 * it, just use SIG_IGN instead).
1661 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1664 if (valid_signal(sig) && sig)
1665 __group_send_sig_info(sig, &info, tsk->parent);
1666 __wake_up_parent(tsk, tsk->parent);
1667 spin_unlock_irqrestore(&psig->siglock, flags);
1673 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1674 * @tsk: task reporting the state change
1675 * @for_ptracer: the notification is for ptracer
1676 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1678 * Notify @tsk's parent that the stopped/continued state has changed. If
1679 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1680 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1683 * Must be called with tasklist_lock at least read locked.
1685 static void do_notify_parent_cldstop(struct task_struct *tsk,
1686 bool for_ptracer, int why)
1688 struct siginfo info;
1689 unsigned long flags;
1690 struct task_struct *parent;
1691 struct sighand_struct *sighand;
1695 parent = tsk->parent;
1697 tsk = tsk->group_leader;
1698 parent = tsk->real_parent;
1701 info.si_signo = SIGCHLD;
1704 * see comment in do_notify_parent() about the following 4 lines
1707 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
1708 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
1711 task_cputime(tsk, &utime, &stime);
1712 info.si_utime = nsec_to_clock_t(utime);
1713 info.si_stime = nsec_to_clock_t(stime);
1718 info.si_status = SIGCONT;
1721 info.si_status = tsk->signal->group_exit_code & 0x7f;
1724 info.si_status = tsk->exit_code & 0x7f;
1730 sighand = parent->sighand;
1731 spin_lock_irqsave(&sighand->siglock, flags);
1732 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1733 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1734 __group_send_sig_info(SIGCHLD, &info, parent);
1736 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1738 __wake_up_parent(tsk, parent);
1739 spin_unlock_irqrestore(&sighand->siglock, flags);
1742 static inline int may_ptrace_stop(void)
1744 if (!likely(current->ptrace))
1747 * Are we in the middle of do_coredump?
1748 * If so and our tracer is also part of the coredump stopping
1749 * is a deadlock situation, and pointless because our tracer
1750 * is dead so don't allow us to stop.
1751 * If SIGKILL was already sent before the caller unlocked
1752 * ->siglock we must see ->core_state != NULL. Otherwise it
1753 * is safe to enter schedule().
1755 * This is almost outdated, a task with the pending SIGKILL can't
1756 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1757 * after SIGKILL was already dequeued.
1759 if (unlikely(current->mm->core_state) &&
1760 unlikely(current->mm == current->parent->mm))
1767 * Return non-zero if there is a SIGKILL that should be waking us up.
1768 * Called with the siglock held.
1770 static int sigkill_pending(struct task_struct *tsk)
1772 return sigismember(&tsk->pending.signal, SIGKILL) ||
1773 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
1777 * This must be called with current->sighand->siglock held.
1779 * This should be the path for all ptrace stops.
1780 * We always set current->last_siginfo while stopped here.
1781 * That makes it a way to test a stopped process for
1782 * being ptrace-stopped vs being job-control-stopped.
1784 * If we actually decide not to stop at all because the tracer
1785 * is gone, we keep current->exit_code unless clear_code.
1787 static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
1788 __releases(¤t->sighand->siglock)
1789 __acquires(¤t->sighand->siglock)
1791 bool gstop_done = false;
1793 if (arch_ptrace_stop_needed(exit_code, info)) {
1795 * The arch code has something special to do before a
1796 * ptrace stop. This is allowed to block, e.g. for faults
1797 * on user stack pages. We can't keep the siglock while
1798 * calling arch_ptrace_stop, so we must release it now.
1799 * To preserve proper semantics, we must do this before
1800 * any signal bookkeeping like checking group_stop_count.
1801 * Meanwhile, a SIGKILL could come in before we retake the
1802 * siglock. That must prevent us from sleeping in TASK_TRACED.
1803 * So after regaining the lock, we must check for SIGKILL.
1805 spin_unlock_irq(¤t->sighand->siglock);
1806 arch_ptrace_stop(exit_code, info);
1807 spin_lock_irq(¤t->sighand->siglock);
1808 if (sigkill_pending(current))
1813 * We're committing to trapping. TRACED should be visible before
1814 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1815 * Also, transition to TRACED and updates to ->jobctl should be
1816 * atomic with respect to siglock and should be done after the arch
1817 * hook as siglock is released and regrabbed across it.
1819 set_current_state(TASK_TRACED);
1821 current->last_siginfo = info;
1822 current->exit_code = exit_code;
1825 * If @why is CLD_STOPPED, we're trapping to participate in a group
1826 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1827 * across siglock relocks since INTERRUPT was scheduled, PENDING
1828 * could be clear now. We act as if SIGCONT is received after
1829 * TASK_TRACED is entered - ignore it.
1831 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
1832 gstop_done = task_participate_group_stop(current);
1834 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1835 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
1836 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
1837 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
1839 /* entering a trap, clear TRAPPING */
1840 task_clear_jobctl_trapping(current);
1842 spin_unlock_irq(¤t->sighand->siglock);
1843 read_lock(&tasklist_lock);
1844 if (may_ptrace_stop()) {
1846 * Notify parents of the stop.
1848 * While ptraced, there are two parents - the ptracer and
1849 * the real_parent of the group_leader. The ptracer should
1850 * know about every stop while the real parent is only
1851 * interested in the completion of group stop. The states
1852 * for the two don't interact with each other. Notify
1853 * separately unless they're gonna be duplicates.
1855 do_notify_parent_cldstop(current, true, why);
1856 if (gstop_done && ptrace_reparented(current))
1857 do_notify_parent_cldstop(current, false, why);
1860 * Don't want to allow preemption here, because
1861 * sys_ptrace() needs this task to be inactive.
1863 * XXX: implement read_unlock_no_resched().
1866 read_unlock(&tasklist_lock);
1867 preempt_enable_no_resched();
1868 freezable_schedule();
1871 * By the time we got the lock, our tracer went away.
1872 * Don't drop the lock yet, another tracer may come.
1874 * If @gstop_done, the ptracer went away between group stop
1875 * completion and here. During detach, it would have set
1876 * JOBCTL_STOP_PENDING on us and we'll re-enter
1877 * TASK_STOPPED in do_signal_stop() on return, so notifying
1878 * the real parent of the group stop completion is enough.
1881 do_notify_parent_cldstop(current, false, why);
1883 /* tasklist protects us from ptrace_freeze_traced() */
1884 __set_current_state(TASK_RUNNING);
1886 current->exit_code = 0;
1887 read_unlock(&tasklist_lock);
1891 * We are back. Now reacquire the siglock before touching
1892 * last_siginfo, so that we are sure to have synchronized with
1893 * any signal-sending on another CPU that wants to examine it.
1895 spin_lock_irq(¤t->sighand->siglock);
1896 current->last_siginfo = NULL;
1898 /* LISTENING can be set only during STOP traps, clear it */
1899 current->jobctl &= ~JOBCTL_LISTENING;
1902 * Queued signals ignored us while we were stopped for tracing.
1903 * So check for any that we should take before resuming user mode.
1904 * This sets TIF_SIGPENDING, but never clears it.
1906 recalc_sigpending_tsk(current);
1909 static void ptrace_do_notify(int signr, int exit_code, int why)
1913 memset(&info, 0, sizeof info);
1914 info.si_signo = signr;
1915 info.si_code = exit_code;
1916 info.si_pid = task_pid_vnr(current);
1917 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1919 /* Let the debugger run. */
1920 ptrace_stop(exit_code, why, 1, &info);
1923 void ptrace_notify(int exit_code)
1925 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1926 if (unlikely(current->task_works))
1929 spin_lock_irq(¤t->sighand->siglock);
1930 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
1931 spin_unlock_irq(¤t->sighand->siglock);
1935 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1936 * @signr: signr causing group stop if initiating
1938 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1939 * and participate in it. If already set, participate in the existing
1940 * group stop. If participated in a group stop (and thus slept), %true is
1941 * returned with siglock released.
1943 * If ptraced, this function doesn't handle stop itself. Instead,
1944 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1945 * untouched. The caller must ensure that INTERRUPT trap handling takes
1946 * places afterwards.
1949 * Must be called with @current->sighand->siglock held, which is released
1953 * %false if group stop is already cancelled or ptrace trap is scheduled.
1954 * %true if participated in group stop.
1956 static bool do_signal_stop(int signr)
1957 __releases(¤t->sighand->siglock)
1959 struct signal_struct *sig = current->signal;
1961 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
1962 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
1963 struct task_struct *t;
1965 /* signr will be recorded in task->jobctl for retries */
1966 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
1968 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
1969 unlikely(signal_group_exit(sig)))
1972 * There is no group stop already in progress. We must
1975 * While ptraced, a task may be resumed while group stop is
1976 * still in effect and then receive a stop signal and
1977 * initiate another group stop. This deviates from the
1978 * usual behavior as two consecutive stop signals can't
1979 * cause two group stops when !ptraced. That is why we
1980 * also check !task_is_stopped(t) below.
1982 * The condition can be distinguished by testing whether
1983 * SIGNAL_STOP_STOPPED is already set. Don't generate
1984 * group_exit_code in such case.
1986 * This is not necessary for SIGNAL_STOP_CONTINUED because
1987 * an intervening stop signal is required to cause two
1988 * continued events regardless of ptrace.
1990 if (!(sig->flags & SIGNAL_STOP_STOPPED))
1991 sig->group_exit_code = signr;
1993 sig->group_stop_count = 0;
1995 if (task_set_jobctl_pending(current, signr | gstop))
1996 sig->group_stop_count++;
1999 while_each_thread(current, t) {
2001 * Setting state to TASK_STOPPED for a group
2002 * stop is always done with the siglock held,
2003 * so this check has no races.
2005 if (!task_is_stopped(t) &&
2006 task_set_jobctl_pending(t, signr | gstop)) {
2007 sig->group_stop_count++;
2008 if (likely(!(t->ptrace & PT_SEIZED)))
2009 signal_wake_up(t, 0);
2011 ptrace_trap_notify(t);
2016 if (likely(!current->ptrace)) {
2020 * If there are no other threads in the group, or if there
2021 * is a group stop in progress and we are the last to stop,
2022 * report to the parent.
2024 if (task_participate_group_stop(current))
2025 notify = CLD_STOPPED;
2027 __set_current_state(TASK_STOPPED);
2028 spin_unlock_irq(¤t->sighand->siglock);
2031 * Notify the parent of the group stop completion. Because
2032 * we're not holding either the siglock or tasklist_lock
2033 * here, ptracer may attach inbetween; however, this is for
2034 * group stop and should always be delivered to the real
2035 * parent of the group leader. The new ptracer will get
2036 * its notification when this task transitions into
2040 read_lock(&tasklist_lock);
2041 do_notify_parent_cldstop(current, false, notify);
2042 read_unlock(&tasklist_lock);
2045 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2046 freezable_schedule();
2050 * While ptraced, group stop is handled by STOP trap.
2051 * Schedule it and let the caller deal with it.
2053 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2059 * do_jobctl_trap - take care of ptrace jobctl traps
2061 * When PT_SEIZED, it's used for both group stop and explicit
2062 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2063 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2064 * the stop signal; otherwise, %SIGTRAP.
2066 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2067 * number as exit_code and no siginfo.
2070 * Must be called with @current->sighand->siglock held, which may be
2071 * released and re-acquired before returning with intervening sleep.
2073 static void do_jobctl_trap(void)
2075 struct signal_struct *signal = current->signal;
2076 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2078 if (current->ptrace & PT_SEIZED) {
2079 if (!signal->group_stop_count &&
2080 !(signal->flags & SIGNAL_STOP_STOPPED))
2082 WARN_ON_ONCE(!signr);
2083 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2086 WARN_ON_ONCE(!signr);
2087 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2088 current->exit_code = 0;
2092 static int ptrace_signal(int signr, siginfo_t *info)
2094 ptrace_signal_deliver();
2096 * We do not check sig_kernel_stop(signr) but set this marker
2097 * unconditionally because we do not know whether debugger will
2098 * change signr. This flag has no meaning unless we are going
2099 * to stop after return from ptrace_stop(). In this case it will
2100 * be checked in do_signal_stop(), we should only stop if it was
2101 * not cleared by SIGCONT while we were sleeping. See also the
2102 * comment in dequeue_signal().
2104 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2105 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2107 /* We're back. Did the debugger cancel the sig? */
2108 signr = current->exit_code;
2112 current->exit_code = 0;
2115 * Update the siginfo structure if the signal has
2116 * changed. If the debugger wanted something
2117 * specific in the siginfo structure then it should
2118 * have updated *info via PTRACE_SETSIGINFO.
2120 if (signr != info->si_signo) {
2121 info->si_signo = signr;
2123 info->si_code = SI_USER;
2125 info->si_pid = task_pid_vnr(current->parent);
2126 info->si_uid = from_kuid_munged(current_user_ns(),
2127 task_uid(current->parent));
2131 /* If the (new) signal is now blocked, requeue it. */
2132 if (sigismember(¤t->blocked, signr)) {
2133 specific_send_sig_info(signr, info, current);
2140 int get_signal(struct ksignal *ksig)
2142 struct sighand_struct *sighand = current->sighand;
2143 struct signal_struct *signal = current->signal;
2146 if (unlikely(current->task_works))
2149 if (unlikely(uprobe_deny_signal()))
2153 * Do this once, we can't return to user-mode if freezing() == T.
2154 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2155 * thus do not need another check after return.
2160 spin_lock_irq(&sighand->siglock);
2162 * Every stopped thread goes here after wakeup. Check to see if
2163 * we should notify the parent, prepare_signal(SIGCONT) encodes
2164 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2166 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2169 if (signal->flags & SIGNAL_CLD_CONTINUED)
2170 why = CLD_CONTINUED;
2174 signal->flags &= ~SIGNAL_CLD_MASK;
2176 spin_unlock_irq(&sighand->siglock);
2179 * Notify the parent that we're continuing. This event is
2180 * always per-process and doesn't make whole lot of sense
2181 * for ptracers, who shouldn't consume the state via
2182 * wait(2) either, but, for backward compatibility, notify
2183 * the ptracer of the group leader too unless it's gonna be
2186 read_lock(&tasklist_lock);
2187 do_notify_parent_cldstop(current, false, why);
2189 if (ptrace_reparented(current->group_leader))
2190 do_notify_parent_cldstop(current->group_leader,
2192 read_unlock(&tasklist_lock);
2198 struct k_sigaction *ka;
2200 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2204 if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
2206 spin_unlock_irq(&sighand->siglock);
2210 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2213 break; /* will return 0 */
2215 if (unlikely(current->ptrace) && signr != SIGKILL) {
2216 signr = ptrace_signal(signr, &ksig->info);
2221 ka = &sighand->action[signr-1];
2223 /* Trace actually delivered signals. */
2224 trace_signal_deliver(signr, &ksig->info, ka);
2226 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2228 if (ka->sa.sa_handler != SIG_DFL) {
2229 /* Run the handler. */
2232 if (ka->sa.sa_flags & SA_ONESHOT)
2233 ka->sa.sa_handler = SIG_DFL;
2235 break; /* will return non-zero "signr" value */
2239 * Now we are doing the default action for this signal.
2241 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2245 * Global init gets no signals it doesn't want.
2246 * Container-init gets no signals it doesn't want from same
2249 * Note that if global/container-init sees a sig_kernel_only()
2250 * signal here, the signal must have been generated internally
2251 * or must have come from an ancestor namespace. In either
2252 * case, the signal cannot be dropped.
2254 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2255 !sig_kernel_only(signr))
2258 if (sig_kernel_stop(signr)) {
2260 * The default action is to stop all threads in
2261 * the thread group. The job control signals
2262 * do nothing in an orphaned pgrp, but SIGSTOP
2263 * always works. Note that siglock needs to be
2264 * dropped during the call to is_orphaned_pgrp()
2265 * because of lock ordering with tasklist_lock.
2266 * This allows an intervening SIGCONT to be posted.
2267 * We need to check for that and bail out if necessary.
2269 if (signr != SIGSTOP) {
2270 spin_unlock_irq(&sighand->siglock);
2272 /* signals can be posted during this window */
2274 if (is_current_pgrp_orphaned())
2277 spin_lock_irq(&sighand->siglock);
2280 if (likely(do_signal_stop(ksig->info.si_signo))) {
2281 /* It released the siglock. */
2286 * We didn't actually stop, due to a race
2287 * with SIGCONT or something like that.
2292 spin_unlock_irq(&sighand->siglock);
2295 * Anything else is fatal, maybe with a core dump.
2297 current->flags |= PF_SIGNALED;
2299 if (sig_kernel_coredump(signr)) {
2300 if (print_fatal_signals)
2301 print_fatal_signal(ksig->info.si_signo);
2302 proc_coredump_connector(current);
2304 * If it was able to dump core, this kills all
2305 * other threads in the group and synchronizes with
2306 * their demise. If we lost the race with another
2307 * thread getting here, it set group_exit_code
2308 * first and our do_group_exit call below will use
2309 * that value and ignore the one we pass it.
2311 do_coredump(&ksig->info);
2315 * Death signals, no core dump.
2317 do_group_exit(ksig->info.si_signo);
2320 spin_unlock_irq(&sighand->siglock);
2323 return ksig->sig > 0;
2327 * signal_delivered -
2328 * @ksig: kernel signal struct
2329 * @stepping: nonzero if debugger single-step or block-step in use
2331 * This function should be called when a signal has successfully been
2332 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2333 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2334 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2336 static void signal_delivered(struct ksignal *ksig, int stepping)
2340 /* A signal was successfully delivered, and the
2341 saved sigmask was stored on the signal frame,
2342 and will be restored by sigreturn. So we can
2343 simply clear the restore sigmask flag. */
2344 clear_restore_sigmask();
2346 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2347 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2348 sigaddset(&blocked, ksig->sig);
2349 set_current_blocked(&blocked);
2350 tracehook_signal_handler(stepping);
2353 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2356 force_sigsegv(ksig->sig, current);
2358 signal_delivered(ksig, stepping);
2362 * It could be that complete_signal() picked us to notify about the
2363 * group-wide signal. Other threads should be notified now to take
2364 * the shared signals in @which since we will not.
2366 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2369 struct task_struct *t;
2371 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2372 if (sigisemptyset(&retarget))
2376 while_each_thread(tsk, t) {
2377 if (t->flags & PF_EXITING)
2380 if (!has_pending_signals(&retarget, &t->blocked))
2382 /* Remove the signals this thread can handle. */
2383 sigandsets(&retarget, &retarget, &t->blocked);
2385 if (!signal_pending(t))
2386 signal_wake_up(t, 0);
2388 if (sigisemptyset(&retarget))
2393 void exit_signals(struct task_struct *tsk)
2399 * @tsk is about to have PF_EXITING set - lock out users which
2400 * expect stable threadgroup.
2402 cgroup_threadgroup_change_begin(tsk);
2404 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2405 tsk->flags |= PF_EXITING;
2406 cgroup_threadgroup_change_end(tsk);
2410 spin_lock_irq(&tsk->sighand->siglock);
2412 * From now this task is not visible for group-wide signals,
2413 * see wants_signal(), do_signal_stop().
2415 tsk->flags |= PF_EXITING;
2417 cgroup_threadgroup_change_end(tsk);
2419 if (!signal_pending(tsk))
2422 unblocked = tsk->blocked;
2423 signotset(&unblocked);
2424 retarget_shared_pending(tsk, &unblocked);
2426 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2427 task_participate_group_stop(tsk))
2428 group_stop = CLD_STOPPED;
2430 spin_unlock_irq(&tsk->sighand->siglock);
2433 * If group stop has completed, deliver the notification. This
2434 * should always go to the real parent of the group leader.
2436 if (unlikely(group_stop)) {
2437 read_lock(&tasklist_lock);
2438 do_notify_parent_cldstop(tsk, false, group_stop);
2439 read_unlock(&tasklist_lock);
2443 EXPORT_SYMBOL(recalc_sigpending);
2444 EXPORT_SYMBOL_GPL(dequeue_signal);
2445 EXPORT_SYMBOL(flush_signals);
2446 EXPORT_SYMBOL(force_sig);
2447 EXPORT_SYMBOL(send_sig);
2448 EXPORT_SYMBOL(send_sig_info);
2449 EXPORT_SYMBOL(sigprocmask);
2452 * System call entry points.
2456 * sys_restart_syscall - restart a system call
2458 SYSCALL_DEFINE0(restart_syscall)
2460 struct restart_block *restart = ¤t->restart_block;
2461 return restart->fn(restart);
2464 long do_no_restart_syscall(struct restart_block *param)
2469 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2471 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2472 sigset_t newblocked;
2473 /* A set of now blocked but previously unblocked signals. */
2474 sigandnsets(&newblocked, newset, ¤t->blocked);
2475 retarget_shared_pending(tsk, &newblocked);
2477 tsk->blocked = *newset;
2478 recalc_sigpending();
2482 * set_current_blocked - change current->blocked mask
2485 * It is wrong to change ->blocked directly, this helper should be used
2486 * to ensure the process can't miss a shared signal we are going to block.
2488 void set_current_blocked(sigset_t *newset)
2490 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2491 __set_current_blocked(newset);
2494 void __set_current_blocked(const sigset_t *newset)
2496 struct task_struct *tsk = current;
2499 * In case the signal mask hasn't changed, there is nothing we need
2500 * to do. The current->blocked shouldn't be modified by other task.
2502 if (sigequalsets(&tsk->blocked, newset))
2505 spin_lock_irq(&tsk->sighand->siglock);
2506 __set_task_blocked(tsk, newset);
2507 spin_unlock_irq(&tsk->sighand->siglock);
2511 * This is also useful for kernel threads that want to temporarily
2512 * (or permanently) block certain signals.
2514 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2515 * interface happily blocks "unblockable" signals like SIGKILL
2518 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2520 struct task_struct *tsk = current;
2523 /* Lockless, only current can change ->blocked, never from irq */
2525 *oldset = tsk->blocked;
2529 sigorsets(&newset, &tsk->blocked, set);
2532 sigandnsets(&newset, &tsk->blocked, set);
2541 __set_current_blocked(&newset);
2546 * sys_rt_sigprocmask - change the list of currently blocked signals
2547 * @how: whether to add, remove, or set signals
2548 * @nset: stores pending signals
2549 * @oset: previous value of signal mask if non-null
2550 * @sigsetsize: size of sigset_t type
2552 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2553 sigset_t __user *, oset, size_t, sigsetsize)
2555 sigset_t old_set, new_set;
2558 /* XXX: Don't preclude handling different sized sigset_t's. */
2559 if (sigsetsize != sizeof(sigset_t))
2562 old_set = current->blocked;
2565 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2567 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2569 error = sigprocmask(how, &new_set, NULL);
2575 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2582 #ifdef CONFIG_COMPAT
2583 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2584 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2587 sigset_t old_set = current->blocked;
2589 /* XXX: Don't preclude handling different sized sigset_t's. */
2590 if (sigsetsize != sizeof(sigset_t))
2594 compat_sigset_t new32;
2597 if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
2600 sigset_from_compat(&new_set, &new32);
2601 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2603 error = sigprocmask(how, &new_set, NULL);
2608 compat_sigset_t old32;
2609 sigset_to_compat(&old32, &old_set);
2610 if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
2615 return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
2616 (sigset_t __user *)oset, sigsetsize);
2621 static int do_sigpending(void *set, unsigned long sigsetsize)
2623 if (sigsetsize > sizeof(sigset_t))
2626 spin_lock_irq(¤t->sighand->siglock);
2627 sigorsets(set, ¤t->pending.signal,
2628 ¤t->signal->shared_pending.signal);
2629 spin_unlock_irq(¤t->sighand->siglock);
2631 /* Outside the lock because only this thread touches it. */
2632 sigandsets(set, ¤t->blocked, set);
2637 * sys_rt_sigpending - examine a pending signal that has been raised
2639 * @uset: stores pending signals
2640 * @sigsetsize: size of sigset_t type or larger
2642 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
2645 int err = do_sigpending(&set, sigsetsize);
2646 if (!err && copy_to_user(uset, &set, sigsetsize))
2651 #ifdef CONFIG_COMPAT
2652 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
2653 compat_size_t, sigsetsize)
2657 int err = do_sigpending(&set, sigsetsize);
2659 compat_sigset_t set32;
2660 sigset_to_compat(&set32, &set);
2661 /* we can get here only if sigsetsize <= sizeof(set) */
2662 if (copy_to_user(uset, &set32, sigsetsize))
2667 return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
2672 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2674 int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
2678 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2680 if (from->si_code < 0)
2681 return __copy_to_user(to, from, sizeof(siginfo_t))
2684 * If you change siginfo_t structure, please be sure
2685 * this code is fixed accordingly.
2686 * Please remember to update the signalfd_copyinfo() function
2687 * inside fs/signalfd.c too, in case siginfo_t changes.
2688 * It should never copy any pad contained in the structure
2689 * to avoid security leaks, but must copy the generic
2690 * 3 ints plus the relevant union member.
2692 err = __put_user(from->si_signo, &to->si_signo);
2693 err |= __put_user(from->si_errno, &to->si_errno);
2694 err |= __put_user((short)from->si_code, &to->si_code);
2695 switch (from->si_code & __SI_MASK) {
2697 err |= __put_user(from->si_pid, &to->si_pid);
2698 err |= __put_user(from->si_uid, &to->si_uid);
2701 err |= __put_user(from->si_tid, &to->si_tid);
2702 err |= __put_user(from->si_overrun, &to->si_overrun);
2703 err |= __put_user(from->si_ptr, &to->si_ptr);
2706 err |= __put_user(from->si_band, &to->si_band);
2707 err |= __put_user(from->si_fd, &to->si_fd);
2710 err |= __put_user(from->si_addr, &to->si_addr);
2711 #ifdef __ARCH_SI_TRAPNO
2712 err |= __put_user(from->si_trapno, &to->si_trapno);
2714 #ifdef BUS_MCEERR_AO
2716 * Other callers might not initialize the si_lsb field,
2717 * so check explicitly for the right codes here.
2719 if (from->si_signo == SIGBUS &&
2720 (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
2721 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2724 if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) {
2725 err |= __put_user(from->si_lower, &to->si_lower);
2726 err |= __put_user(from->si_upper, &to->si_upper);
2730 if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR)
2731 err |= __put_user(from->si_pkey, &to->si_pkey);
2735 err |= __put_user(from->si_pid, &to->si_pid);
2736 err |= __put_user(from->si_uid, &to->si_uid);
2737 err |= __put_user(from->si_status, &to->si_status);
2738 err |= __put_user(from->si_utime, &to->si_utime);
2739 err |= __put_user(from->si_stime, &to->si_stime);
2741 case __SI_RT: /* This is not generated by the kernel as of now. */
2742 case __SI_MESGQ: /* But this is */
2743 err |= __put_user(from->si_pid, &to->si_pid);
2744 err |= __put_user(from->si_uid, &to->si_uid);
2745 err |= __put_user(from->si_ptr, &to->si_ptr);
2747 #ifdef __ARCH_SIGSYS
2749 err |= __put_user(from->si_call_addr, &to->si_call_addr);
2750 err |= __put_user(from->si_syscall, &to->si_syscall);
2751 err |= __put_user(from->si_arch, &to->si_arch);
2754 default: /* this is just in case for now ... */
2755 err |= __put_user(from->si_pid, &to->si_pid);
2756 err |= __put_user(from->si_uid, &to->si_uid);
2765 * do_sigtimedwait - wait for queued signals specified in @which
2766 * @which: queued signals to wait for
2767 * @info: if non-null, the signal's siginfo is returned here
2768 * @ts: upper bound on process time suspension
2770 int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
2771 const struct timespec *ts)
2773 ktime_t *to = NULL, timeout = KTIME_MAX;
2774 struct task_struct *tsk = current;
2775 sigset_t mask = *which;
2779 if (!timespec_valid(ts))
2781 timeout = timespec_to_ktime(*ts);
2786 * Invert the set of allowed signals to get those we want to block.
2788 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
2791 spin_lock_irq(&tsk->sighand->siglock);
2792 sig = dequeue_signal(tsk, &mask, info);
2793 if (!sig && timeout) {
2795 * None ready, temporarily unblock those we're interested
2796 * while we are sleeping in so that we'll be awakened when
2797 * they arrive. Unblocking is always fine, we can avoid
2798 * set_current_blocked().
2800 tsk->real_blocked = tsk->blocked;
2801 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
2802 recalc_sigpending();
2803 spin_unlock_irq(&tsk->sighand->siglock);
2805 __set_current_state(TASK_INTERRUPTIBLE);
2806 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
2808 spin_lock_irq(&tsk->sighand->siglock);
2809 __set_task_blocked(tsk, &tsk->real_blocked);
2810 sigemptyset(&tsk->real_blocked);
2811 sig = dequeue_signal(tsk, &mask, info);
2813 spin_unlock_irq(&tsk->sighand->siglock);
2817 return ret ? -EINTR : -EAGAIN;
2821 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2823 * @uthese: queued signals to wait for
2824 * @uinfo: if non-null, the signal's siginfo is returned here
2825 * @uts: upper bound on process time suspension
2826 * @sigsetsize: size of sigset_t type
2828 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2829 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2837 /* XXX: Don't preclude handling different sized sigset_t's. */
2838 if (sigsetsize != sizeof(sigset_t))
2841 if (copy_from_user(&these, uthese, sizeof(these)))
2845 if (copy_from_user(&ts, uts, sizeof(ts)))
2849 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
2851 if (ret > 0 && uinfo) {
2852 if (copy_siginfo_to_user(uinfo, &info))
2860 * sys_kill - send a signal to a process
2861 * @pid: the PID of the process
2862 * @sig: signal to be sent
2864 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2866 struct siginfo info;
2868 info.si_signo = sig;
2870 info.si_code = SI_USER;
2871 info.si_pid = task_tgid_vnr(current);
2872 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2874 return kill_something_info(sig, &info, pid);
2878 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2880 struct task_struct *p;
2884 p = find_task_by_vpid(pid);
2885 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2886 error = check_kill_permission(sig, info, p);
2888 * The null signal is a permissions and process existence
2889 * probe. No signal is actually delivered.
2891 if (!error && sig) {
2892 error = do_send_sig_info(sig, info, p, false);
2894 * If lock_task_sighand() failed we pretend the task
2895 * dies after receiving the signal. The window is tiny,
2896 * and the signal is private anyway.
2898 if (unlikely(error == -ESRCH))
2907 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2909 struct siginfo info = {};
2911 info.si_signo = sig;
2913 info.si_code = SI_TKILL;
2914 info.si_pid = task_tgid_vnr(current);
2915 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2917 return do_send_specific(tgid, pid, sig, &info);
2921 * sys_tgkill - send signal to one specific thread
2922 * @tgid: the thread group ID of the thread
2923 * @pid: the PID of the thread
2924 * @sig: signal to be sent
2926 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2927 * exists but it's not belonging to the target process anymore. This
2928 * method solves the problem of threads exiting and PIDs getting reused.
2930 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2932 /* This is only valid for single tasks */
2933 if (pid <= 0 || tgid <= 0)
2936 return do_tkill(tgid, pid, sig);
2940 * sys_tkill - send signal to one specific task
2941 * @pid: the PID of the task
2942 * @sig: signal to be sent
2944 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2946 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
2948 /* This is only valid for single tasks */
2952 return do_tkill(0, pid, sig);
2955 static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
2957 /* Not even root can pretend to send signals from the kernel.
2958 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2960 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
2961 (task_pid_vnr(current) != pid))
2964 info->si_signo = sig;
2966 /* POSIX.1b doesn't mention process groups. */
2967 return kill_proc_info(sig, info, pid);
2971 * sys_rt_sigqueueinfo - send signal information to a signal
2972 * @pid: the PID of the thread
2973 * @sig: signal to be sent
2974 * @uinfo: signal info to be sent
2976 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
2977 siginfo_t __user *, uinfo)
2980 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2982 return do_rt_sigqueueinfo(pid, sig, &info);
2985 #ifdef CONFIG_COMPAT
2986 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
2989 struct compat_siginfo __user *, uinfo)
2991 siginfo_t info = {};
2992 int ret = copy_siginfo_from_user32(&info, uinfo);
2995 return do_rt_sigqueueinfo(pid, sig, &info);
2999 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
3001 /* This is only valid for single tasks */
3002 if (pid <= 0 || tgid <= 0)
3005 /* Not even root can pretend to send signals from the kernel.
3006 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3008 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3009 (task_pid_vnr(current) != pid))
3012 info->si_signo = sig;
3014 return do_send_specific(tgid, pid, sig, info);
3017 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3018 siginfo_t __user *, uinfo)
3022 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3025 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3028 #ifdef CONFIG_COMPAT
3029 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3033 struct compat_siginfo __user *, uinfo)
3035 siginfo_t info = {};
3037 if (copy_siginfo_from_user32(&info, uinfo))
3039 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3044 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3046 void kernel_sigaction(int sig, __sighandler_t action)
3048 spin_lock_irq(¤t->sighand->siglock);
3049 current->sighand->action[sig - 1].sa.sa_handler = action;
3050 if (action == SIG_IGN) {
3054 sigaddset(&mask, sig);
3056 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3057 flush_sigqueue_mask(&mask, ¤t->pending);
3058 recalc_sigpending();
3060 spin_unlock_irq(¤t->sighand->siglock);
3062 EXPORT_SYMBOL(kernel_sigaction);
3064 void __weak sigaction_compat_abi(struct k_sigaction *act,
3065 struct k_sigaction *oact)
3069 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3071 struct task_struct *p = current, *t;
3072 struct k_sigaction *k;
3075 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3078 k = &p->sighand->action[sig-1];
3080 spin_lock_irq(&p->sighand->siglock);
3084 sigaction_compat_abi(act, oact);
3087 sigdelsetmask(&act->sa.sa_mask,
3088 sigmask(SIGKILL) | sigmask(SIGSTOP));
3092 * "Setting a signal action to SIG_IGN for a signal that is
3093 * pending shall cause the pending signal to be discarded,
3094 * whether or not it is blocked."
3096 * "Setting a signal action to SIG_DFL for a signal that is
3097 * pending and whose default action is to ignore the signal
3098 * (for example, SIGCHLD), shall cause the pending signal to
3099 * be discarded, whether or not it is blocked"
3101 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3103 sigaddset(&mask, sig);
3104 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3105 for_each_thread(p, t)
3106 flush_sigqueue_mask(&mask, &t->pending);
3110 spin_unlock_irq(&p->sighand->siglock);
3115 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
3120 oss.ss_sp = (void __user *) current->sas_ss_sp;
3121 oss.ss_size = current->sas_ss_size;
3122 oss.ss_flags = sas_ss_flags(sp) |
3123 (current->sas_ss_flags & SS_FLAG_BITS);
3132 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
3134 error = __get_user(ss_sp, &uss->ss_sp) |
3135 __get_user(ss_flags, &uss->ss_flags) |
3136 __get_user(ss_size, &uss->ss_size);
3141 if (on_sig_stack(sp))
3144 ss_mode = ss_flags & ~SS_FLAG_BITS;
3146 if (ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
3150 if (ss_mode == SS_DISABLE) {
3155 if (ss_size < MINSIGSTKSZ)
3159 current->sas_ss_sp = (unsigned long) ss_sp;
3160 current->sas_ss_size = ss_size;
3161 current->sas_ss_flags = ss_flags;
3167 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
3169 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
3170 __put_user(oss.ss_size, &uoss->ss_size) |
3171 __put_user(oss.ss_flags, &uoss->ss_flags);
3177 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3179 return do_sigaltstack(uss, uoss, current_user_stack_pointer());
3182 int restore_altstack(const stack_t __user *uss)
3184 int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
3185 /* squash all but EFAULT for now */
3186 return err == -EFAULT ? err : 0;
3189 int __save_altstack(stack_t __user *uss, unsigned long sp)
3191 struct task_struct *t = current;
3192 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3193 __put_user(t->sas_ss_flags, &uss->ss_flags) |
3194 __put_user(t->sas_ss_size, &uss->ss_size);
3197 if (t->sas_ss_flags & SS_AUTODISARM)
3202 #ifdef CONFIG_COMPAT
3203 COMPAT_SYSCALL_DEFINE2(sigaltstack,
3204 const compat_stack_t __user *, uss_ptr,
3205 compat_stack_t __user *, uoss_ptr)
3212 compat_stack_t uss32;
3214 memset(&uss, 0, sizeof(stack_t));
3215 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
3217 uss.ss_sp = compat_ptr(uss32.ss_sp);
3218 uss.ss_flags = uss32.ss_flags;
3219 uss.ss_size = uss32.ss_size;
3223 ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
3224 (stack_t __force __user *) &uoss,
3225 compat_user_stack_pointer());
3227 if (ret >= 0 && uoss_ptr) {
3228 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
3229 __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
3230 __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
3231 __put_user(uoss.ss_size, &uoss_ptr->ss_size))
3237 int compat_restore_altstack(const compat_stack_t __user *uss)
3239 int err = compat_sys_sigaltstack(uss, NULL);
3240 /* squash all but -EFAULT for now */
3241 return err == -EFAULT ? err : 0;
3244 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
3247 struct task_struct *t = current;
3248 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
3250 __put_user(t->sas_ss_flags, &uss->ss_flags) |
3251 __put_user(t->sas_ss_size, &uss->ss_size);
3254 if (t->sas_ss_flags & SS_AUTODISARM)
3260 #ifdef __ARCH_WANT_SYS_SIGPENDING
3263 * sys_sigpending - examine pending signals
3264 * @set: where mask of pending signal is returned
3266 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
3268 return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
3273 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3275 * sys_sigprocmask - examine and change blocked signals
3276 * @how: whether to add, remove, or set signals
3277 * @nset: signals to add or remove (if non-null)
3278 * @oset: previous value of signal mask if non-null
3280 * Some platforms have their own version with special arguments;
3281 * others support only sys_rt_sigprocmask.
3284 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
3285 old_sigset_t __user *, oset)
3287 old_sigset_t old_set, new_set;
3288 sigset_t new_blocked;
3290 old_set = current->blocked.sig[0];
3293 if (copy_from_user(&new_set, nset, sizeof(*nset)))
3296 new_blocked = current->blocked;
3300 sigaddsetmask(&new_blocked, new_set);
3303 sigdelsetmask(&new_blocked, new_set);
3306 new_blocked.sig[0] = new_set;
3312 set_current_blocked(&new_blocked);
3316 if (copy_to_user(oset, &old_set, sizeof(*oset)))
3322 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3324 #ifndef CONFIG_ODD_RT_SIGACTION
3326 * sys_rt_sigaction - alter an action taken by a process
3327 * @sig: signal to be sent
3328 * @act: new sigaction
3329 * @oact: used to save the previous sigaction
3330 * @sigsetsize: size of sigset_t type
3332 SYSCALL_DEFINE4(rt_sigaction, int, sig,
3333 const struct sigaction __user *, act,
3334 struct sigaction __user *, oact,
3337 struct k_sigaction new_sa, old_sa;
3340 /* XXX: Don't preclude handling different sized sigset_t's. */
3341 if (sigsetsize != sizeof(sigset_t))
3345 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
3349 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
3352 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
3358 #ifdef CONFIG_COMPAT
3359 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
3360 const struct compat_sigaction __user *, act,
3361 struct compat_sigaction __user *, oact,
3362 compat_size_t, sigsetsize)
3364 struct k_sigaction new_ka, old_ka;
3365 compat_sigset_t mask;
3366 #ifdef __ARCH_HAS_SA_RESTORER
3367 compat_uptr_t restorer;
3371 /* XXX: Don't preclude handling different sized sigset_t's. */
3372 if (sigsetsize != sizeof(compat_sigset_t))
3376 compat_uptr_t handler;
3377 ret = get_user(handler, &act->sa_handler);
3378 new_ka.sa.sa_handler = compat_ptr(handler);
3379 #ifdef __ARCH_HAS_SA_RESTORER
3380 ret |= get_user(restorer, &act->sa_restorer);
3381 new_ka.sa.sa_restorer = compat_ptr(restorer);
3383 ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
3384 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
3387 sigset_from_compat(&new_ka.sa.sa_mask, &mask);
3390 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3392 sigset_to_compat(&mask, &old_ka.sa.sa_mask);
3393 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
3395 ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
3396 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
3397 #ifdef __ARCH_HAS_SA_RESTORER
3398 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3399 &oact->sa_restorer);
3405 #endif /* !CONFIG_ODD_RT_SIGACTION */
3407 #ifdef CONFIG_OLD_SIGACTION
3408 SYSCALL_DEFINE3(sigaction, int, sig,
3409 const struct old_sigaction __user *, act,
3410 struct old_sigaction __user *, oact)
3412 struct k_sigaction new_ka, old_ka;
3417 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3418 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
3419 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
3420 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3421 __get_user(mask, &act->sa_mask))
3423 #ifdef __ARCH_HAS_KA_RESTORER
3424 new_ka.ka_restorer = NULL;
3426 siginitset(&new_ka.sa.sa_mask, mask);
3429 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3432 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3433 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
3434 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
3435 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3436 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3443 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3444 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
3445 const struct compat_old_sigaction __user *, act,
3446 struct compat_old_sigaction __user *, oact)
3448 struct k_sigaction new_ka, old_ka;
3450 compat_old_sigset_t mask;
3451 compat_uptr_t handler, restorer;
3454 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3455 __get_user(handler, &act->sa_handler) ||
3456 __get_user(restorer, &act->sa_restorer) ||
3457 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3458 __get_user(mask, &act->sa_mask))
3461 #ifdef __ARCH_HAS_KA_RESTORER
3462 new_ka.ka_restorer = NULL;
3464 new_ka.sa.sa_handler = compat_ptr(handler);
3465 new_ka.sa.sa_restorer = compat_ptr(restorer);
3466 siginitset(&new_ka.sa.sa_mask, mask);
3469 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3472 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3473 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
3474 &oact->sa_handler) ||
3475 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3476 &oact->sa_restorer) ||
3477 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3478 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3485 #ifdef CONFIG_SGETMASK_SYSCALL
3488 * For backwards compatibility. Functionality superseded by sigprocmask.
3490 SYSCALL_DEFINE0(sgetmask)
3493 return current->blocked.sig[0];
3496 SYSCALL_DEFINE1(ssetmask, int, newmask)
3498 int old = current->blocked.sig[0];
3501 siginitset(&newset, newmask);
3502 set_current_blocked(&newset);
3506 #endif /* CONFIG_SGETMASK_SYSCALL */
3508 #ifdef __ARCH_WANT_SYS_SIGNAL
3510 * For backwards compatibility. Functionality superseded by sigaction.
3512 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
3514 struct k_sigaction new_sa, old_sa;
3517 new_sa.sa.sa_handler = handler;
3518 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
3519 sigemptyset(&new_sa.sa.sa_mask);
3521 ret = do_sigaction(sig, &new_sa, &old_sa);
3523 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
3525 #endif /* __ARCH_WANT_SYS_SIGNAL */
3527 #ifdef __ARCH_WANT_SYS_PAUSE
3529 SYSCALL_DEFINE0(pause)
3531 while (!signal_pending(current)) {
3532 __set_current_state(TASK_INTERRUPTIBLE);
3535 return -ERESTARTNOHAND;
3540 static int sigsuspend(sigset_t *set)
3542 current->saved_sigmask = current->blocked;
3543 set_current_blocked(set);
3545 while (!signal_pending(current)) {
3546 __set_current_state(TASK_INTERRUPTIBLE);
3549 set_restore_sigmask();
3550 return -ERESTARTNOHAND;
3554 * sys_rt_sigsuspend - replace the signal mask for a value with the
3555 * @unewset value until a signal is received
3556 * @unewset: new signal mask value
3557 * @sigsetsize: size of sigset_t type
3559 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
3563 /* XXX: Don't preclude handling different sized sigset_t's. */
3564 if (sigsetsize != sizeof(sigset_t))
3567 if (copy_from_user(&newset, unewset, sizeof(newset)))
3569 return sigsuspend(&newset);
3572 #ifdef CONFIG_COMPAT
3573 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
3577 compat_sigset_t newset32;
3579 /* XXX: Don't preclude handling different sized sigset_t's. */
3580 if (sigsetsize != sizeof(sigset_t))
3583 if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
3585 sigset_from_compat(&newset, &newset32);
3586 return sigsuspend(&newset);
3588 /* on little-endian bitmaps don't care about granularity */
3589 return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize);
3594 #ifdef CONFIG_OLD_SIGSUSPEND
3595 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
3598 siginitset(&blocked, mask);
3599 return sigsuspend(&blocked);
3602 #ifdef CONFIG_OLD_SIGSUSPEND3
3603 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
3606 siginitset(&blocked, mask);
3607 return sigsuspend(&blocked);
3611 __weak const char *arch_vma_name(struct vm_area_struct *vma)
3616 void __init signals_init(void)
3618 /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */
3619 BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE
3620 != offsetof(struct siginfo, _sifields._pad));
3622 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
3625 #ifdef CONFIG_KGDB_KDB
3626 #include <linux/kdb.h>
3628 * kdb_send_sig_info - Allows kdb to send signals without exposing
3629 * signal internals. This function checks if the required locks are
3630 * available before calling the main signal code, to avoid kdb
3634 kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
3636 static struct task_struct *kdb_prev_t;
3638 if (!spin_trylock(&t->sighand->siglock)) {
3639 kdb_printf("Can't do kill command now.\n"
3640 "The sigmask lock is held somewhere else in "
3641 "kernel, try again later\n");
3644 spin_unlock(&t->sighand->siglock);
3645 new_t = kdb_prev_t != t;
3647 if (t->state != TASK_RUNNING && new_t) {
3648 kdb_printf("Process is not RUNNING, sending a signal from "
3649 "kdb risks deadlock\n"
3650 "on the run queue locks. "
3651 "The signal has _not_ been sent.\n"
3652 "Reissue the kill command if you want to risk "
3656 sig = info->si_signo;
3657 if (send_sig_info(sig, info, t))
3658 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3661 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
3663 #endif /* CONFIG_KGDB_KDB */