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 && sig_kernel_only(sig)))
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))
92 * Tracers may want to know about even ignored signal unless it
93 * is SIGKILL which can't be reported anyway but can be ignored
94 * by SIGNAL_UNKILLABLE task.
96 if (t->ptrace && sig != SIGKILL)
99 return sig_task_ignored(t, sig, force);
103 * Re-calculate pending state from the set of locally pending
104 * signals, globally pending signals, and blocked signals.
106 static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
111 switch (_NSIG_WORDS) {
113 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
114 ready |= signal->sig[i] &~ blocked->sig[i];
117 case 4: ready = signal->sig[3] &~ blocked->sig[3];
118 ready |= signal->sig[2] &~ blocked->sig[2];
119 ready |= signal->sig[1] &~ blocked->sig[1];
120 ready |= signal->sig[0] &~ blocked->sig[0];
123 case 2: ready = signal->sig[1] &~ blocked->sig[1];
124 ready |= signal->sig[0] &~ blocked->sig[0];
127 case 1: ready = signal->sig[0] &~ blocked->sig[0];
132 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
134 static int recalc_sigpending_tsk(struct task_struct *t)
136 if ((t->jobctl & JOBCTL_PENDING_MASK) ||
137 PENDING(&t->pending, &t->blocked) ||
138 PENDING(&t->signal->shared_pending, &t->blocked)) {
139 set_tsk_thread_flag(t, TIF_SIGPENDING);
143 * We must never clear the flag in another thread, or in current
144 * when it's possible the current syscall is returning -ERESTART*.
145 * So we don't clear it here, and only callers who know they should do.
151 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
152 * This is superfluous when called on current, the wakeup is a harmless no-op.
154 void recalc_sigpending_and_wake(struct task_struct *t)
156 if (recalc_sigpending_tsk(t))
157 signal_wake_up(t, 0);
160 void recalc_sigpending(void)
162 if (!recalc_sigpending_tsk(current) && !freezing(current))
163 clear_thread_flag(TIF_SIGPENDING);
167 /* Given the mask, find the first available signal that should be serviced. */
169 #define SYNCHRONOUS_MASK \
170 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
171 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
173 int next_signal(struct sigpending *pending, sigset_t *mask)
175 unsigned long i, *s, *m, x;
178 s = pending->signal.sig;
182 * Handle the first word specially: it contains the
183 * synchronous signals that need to be dequeued first.
187 if (x & SYNCHRONOUS_MASK)
188 x &= SYNCHRONOUS_MASK;
193 switch (_NSIG_WORDS) {
195 for (i = 1; i < _NSIG_WORDS; ++i) {
199 sig = ffz(~x) + i*_NSIG_BPW + 1;
208 sig = ffz(~x) + _NSIG_BPW + 1;
219 static inline void print_dropped_signal(int sig)
221 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
223 if (!print_fatal_signals)
226 if (!__ratelimit(&ratelimit_state))
229 printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
230 current->comm, current->pid, sig);
234 * task_set_jobctl_pending - set jobctl pending bits
236 * @mask: pending bits to set
238 * Clear @mask from @task->jobctl. @mask must be subset of
239 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
240 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
241 * cleared. If @task is already being killed or exiting, this function
245 * Must be called with @task->sighand->siglock held.
248 * %true if @mask is set, %false if made noop because @task was dying.
250 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
252 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
253 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
254 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
256 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
259 if (mask & JOBCTL_STOP_SIGMASK)
260 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
262 task->jobctl |= mask;
267 * task_clear_jobctl_trapping - clear jobctl trapping bit
270 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
271 * Clear it and wake up the ptracer. Note that we don't need any further
272 * locking. @task->siglock guarantees that @task->parent points to the
276 * Must be called with @task->sighand->siglock held.
278 void task_clear_jobctl_trapping(struct task_struct *task)
280 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
281 task->jobctl &= ~JOBCTL_TRAPPING;
282 smp_mb(); /* advised by wake_up_bit() */
283 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
288 * task_clear_jobctl_pending - clear jobctl pending bits
290 * @mask: pending bits to clear
292 * Clear @mask from @task->jobctl. @mask must be subset of
293 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
294 * STOP bits are cleared together.
296 * If clearing of @mask leaves no stop or trap pending, this function calls
297 * task_clear_jobctl_trapping().
300 * Must be called with @task->sighand->siglock held.
302 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
304 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
306 if (mask & JOBCTL_STOP_PENDING)
307 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
309 task->jobctl &= ~mask;
311 if (!(task->jobctl & JOBCTL_PENDING_MASK))
312 task_clear_jobctl_trapping(task);
316 * task_participate_group_stop - participate in a group stop
317 * @task: task participating in a group stop
319 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
320 * Group stop states are cleared and the group stop count is consumed if
321 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
322 * stop, the appropriate %SIGNAL_* flags are set.
325 * Must be called with @task->sighand->siglock held.
328 * %true if group stop completion should be notified to the parent, %false
331 static bool task_participate_group_stop(struct task_struct *task)
333 struct signal_struct *sig = task->signal;
334 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
336 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
338 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
343 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
344 sig->group_stop_count--;
347 * Tell the caller to notify completion iff we are entering into a
348 * fresh group stop. Read comment in do_signal_stop() for details.
350 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
351 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
358 * allocate a new signal queue record
359 * - this may be called without locks if and only if t == current, otherwise an
360 * appropriate lock must be held to stop the target task from exiting
362 static struct sigqueue *
363 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
365 struct sigqueue *q = NULL;
366 struct user_struct *user;
369 * Protect access to @t credentials. This can go away when all
370 * callers hold rcu read lock.
373 user = get_uid(__task_cred(t)->user);
374 atomic_inc(&user->sigpending);
377 if (override_rlimit ||
378 atomic_read(&user->sigpending) <=
379 task_rlimit(t, RLIMIT_SIGPENDING)) {
380 q = kmem_cache_alloc(sigqueue_cachep, flags);
382 print_dropped_signal(sig);
385 if (unlikely(q == NULL)) {
386 atomic_dec(&user->sigpending);
389 INIT_LIST_HEAD(&q->list);
397 static void __sigqueue_free(struct sigqueue *q)
399 if (q->flags & SIGQUEUE_PREALLOC)
401 atomic_dec(&q->user->sigpending);
403 kmem_cache_free(sigqueue_cachep, q);
406 void flush_sigqueue(struct sigpending *queue)
410 sigemptyset(&queue->signal);
411 while (!list_empty(&queue->list)) {
412 q = list_entry(queue->list.next, struct sigqueue , list);
413 list_del_init(&q->list);
419 * Flush all pending signals for this kthread.
421 void flush_signals(struct task_struct *t)
425 spin_lock_irqsave(&t->sighand->siglock, flags);
426 clear_tsk_thread_flag(t, TIF_SIGPENDING);
427 flush_sigqueue(&t->pending);
428 flush_sigqueue(&t->signal->shared_pending);
429 spin_unlock_irqrestore(&t->sighand->siglock, flags);
432 static void __flush_itimer_signals(struct sigpending *pending)
434 sigset_t signal, retain;
435 struct sigqueue *q, *n;
437 signal = pending->signal;
438 sigemptyset(&retain);
440 list_for_each_entry_safe(q, n, &pending->list, list) {
441 int sig = q->info.si_signo;
443 if (likely(q->info.si_code != SI_TIMER)) {
444 sigaddset(&retain, sig);
446 sigdelset(&signal, sig);
447 list_del_init(&q->list);
452 sigorsets(&pending->signal, &signal, &retain);
455 void flush_itimer_signals(void)
457 struct task_struct *tsk = current;
460 spin_lock_irqsave(&tsk->sighand->siglock, flags);
461 __flush_itimer_signals(&tsk->pending);
462 __flush_itimer_signals(&tsk->signal->shared_pending);
463 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
466 void ignore_signals(struct task_struct *t)
470 for (i = 0; i < _NSIG; ++i)
471 t->sighand->action[i].sa.sa_handler = SIG_IGN;
477 * Flush all handlers for a task.
481 flush_signal_handlers(struct task_struct *t, int force_default)
484 struct k_sigaction *ka = &t->sighand->action[0];
485 for (i = _NSIG ; i != 0 ; i--) {
486 if (force_default || ka->sa.sa_handler != SIG_IGN)
487 ka->sa.sa_handler = SIG_DFL;
489 #ifdef __ARCH_HAS_SA_RESTORER
490 ka->sa.sa_restorer = NULL;
492 sigemptyset(&ka->sa.sa_mask);
497 int unhandled_signal(struct task_struct *tsk, int sig)
499 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
500 if (is_global_init(tsk))
502 if (handler != SIG_IGN && handler != SIG_DFL)
504 /* if ptraced, let the tracer determine */
508 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
511 struct sigqueue *q, *first = NULL;
514 * Collect the siginfo appropriate to this signal. Check if
515 * there is another siginfo for the same signal.
517 list_for_each_entry(q, &list->list, list) {
518 if (q->info.si_signo == sig) {
525 sigdelset(&list->signal, sig);
529 list_del_init(&first->list);
530 copy_siginfo(info, &first->info);
533 (first->flags & SIGQUEUE_PREALLOC) &&
534 (info->si_code == SI_TIMER) &&
535 (info->si_sys_private);
537 __sigqueue_free(first);
540 * Ok, it wasn't in the queue. This must be
541 * a fast-pathed signal or we must have been
542 * out of queue space. So zero out the info.
544 info->si_signo = sig;
546 info->si_code = SI_USER;
552 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
553 siginfo_t *info, bool *resched_timer)
555 int sig = next_signal(pending, mask);
558 collect_signal(sig, pending, info, resched_timer);
563 * Dequeue a signal and return the element to the caller, which is
564 * expected to free it.
566 * All callers have to hold the siglock.
568 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
570 bool resched_timer = false;
573 /* We only dequeue private signals from ourselves, we don't let
574 * signalfd steal them
576 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
578 signr = __dequeue_signal(&tsk->signal->shared_pending,
579 mask, info, &resched_timer);
583 * itimers are process shared and we restart periodic
584 * itimers in the signal delivery path to prevent DoS
585 * attacks in the high resolution timer case. This is
586 * compliant with the old way of self-restarting
587 * itimers, as the SIGALRM is a legacy signal and only
588 * queued once. Changing the restart behaviour to
589 * restart the timer in the signal dequeue path is
590 * reducing the timer noise on heavy loaded !highres
593 if (unlikely(signr == SIGALRM)) {
594 struct hrtimer *tmr = &tsk->signal->real_timer;
596 if (!hrtimer_is_queued(tmr) &&
597 tsk->signal->it_real_incr.tv64 != 0) {
598 hrtimer_forward(tmr, tmr->base->get_time(),
599 tsk->signal->it_real_incr);
600 hrtimer_restart(tmr);
609 if (unlikely(sig_kernel_stop(signr))) {
611 * Set a marker that we have dequeued a stop signal. Our
612 * caller might release the siglock and then the pending
613 * stop signal it is about to process is no longer in the
614 * pending bitmasks, but must still be cleared by a SIGCONT
615 * (and overruled by a SIGKILL). So those cases clear this
616 * shared flag after we've set it. Note that this flag may
617 * remain set after the signal we return is ignored or
618 * handled. That doesn't matter because its only purpose
619 * is to alert stop-signal processing code when another
620 * processor has come along and cleared the flag.
622 current->jobctl |= JOBCTL_STOP_DEQUEUED;
626 * Release the siglock to ensure proper locking order
627 * of timer locks outside of siglocks. Note, we leave
628 * irqs disabled here, since the posix-timers code is
629 * about to disable them again anyway.
631 spin_unlock(&tsk->sighand->siglock);
632 do_schedule_next_timer(info);
633 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_GROUP_EXIT) &&
923 !sigismember(&t->real_blocked, sig) &&
924 (sig == SIGKILL || !p->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 printk(KERN_INFO "potentially unexpected fatal signal %d.\n", signr);
1104 #if defined(__i386__) && !defined(__arch_um__)
1105 printk(KERN_INFO "code at %08lx: ", regs->ip);
1108 for (i = 0; i < 16; i++) {
1111 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1113 printk(KERN_CONT "%02x ", insn);
1116 printk(KERN_CONT "\n");
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;
1588 cputime_t utime, stime;
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 = cputime_to_clock_t(utime + tsk->signal->utime);
1628 info.si_stime = cputime_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;
1692 cputime_t utime, stime;
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 = cputime_to_clock_t(utime);
1713 info.si_stime = cputime_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 threadgroup_change_begin(tsk);
2404 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2405 tsk->flags |= PF_EXITING;
2406 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 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;
2498 spin_lock_irq(&tsk->sighand->siglock);
2499 __set_task_blocked(tsk, newset);
2500 spin_unlock_irq(&tsk->sighand->siglock);
2504 * This is also useful for kernel threads that want to temporarily
2505 * (or permanently) block certain signals.
2507 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2508 * interface happily blocks "unblockable" signals like SIGKILL
2511 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2513 struct task_struct *tsk = current;
2516 /* Lockless, only current can change ->blocked, never from irq */
2518 *oldset = tsk->blocked;
2522 sigorsets(&newset, &tsk->blocked, set);
2525 sigandnsets(&newset, &tsk->blocked, set);
2534 __set_current_blocked(&newset);
2539 * sys_rt_sigprocmask - change the list of currently blocked signals
2540 * @how: whether to add, remove, or set signals
2541 * @nset: stores pending signals
2542 * @oset: previous value of signal mask if non-null
2543 * @sigsetsize: size of sigset_t type
2545 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2546 sigset_t __user *, oset, size_t, sigsetsize)
2548 sigset_t old_set, new_set;
2551 /* XXX: Don't preclude handling different sized sigset_t's. */
2552 if (sigsetsize != sizeof(sigset_t))
2555 old_set = current->blocked;
2558 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2560 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2562 error = sigprocmask(how, &new_set, NULL);
2568 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2575 #ifdef CONFIG_COMPAT
2576 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2577 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2580 sigset_t old_set = current->blocked;
2582 /* XXX: Don't preclude handling different sized sigset_t's. */
2583 if (sigsetsize != sizeof(sigset_t))
2587 compat_sigset_t new32;
2590 if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
2593 sigset_from_compat(&new_set, &new32);
2594 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2596 error = sigprocmask(how, &new_set, NULL);
2601 compat_sigset_t old32;
2602 sigset_to_compat(&old32, &old_set);
2603 if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
2608 return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
2609 (sigset_t __user *)oset, sigsetsize);
2614 static int do_sigpending(void *set, unsigned long sigsetsize)
2616 if (sigsetsize > sizeof(sigset_t))
2619 spin_lock_irq(¤t->sighand->siglock);
2620 sigorsets(set, ¤t->pending.signal,
2621 ¤t->signal->shared_pending.signal);
2622 spin_unlock_irq(¤t->sighand->siglock);
2624 /* Outside the lock because only this thread touches it. */
2625 sigandsets(set, ¤t->blocked, set);
2630 * sys_rt_sigpending - examine a pending signal that has been raised
2632 * @uset: stores pending signals
2633 * @sigsetsize: size of sigset_t type or larger
2635 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
2638 int err = do_sigpending(&set, sigsetsize);
2639 if (!err && copy_to_user(uset, &set, sigsetsize))
2644 #ifdef CONFIG_COMPAT
2645 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
2646 compat_size_t, sigsetsize)
2650 int err = do_sigpending(&set, sigsetsize);
2652 compat_sigset_t set32;
2653 sigset_to_compat(&set32, &set);
2654 /* we can get here only if sigsetsize <= sizeof(set) */
2655 if (copy_to_user(uset, &set32, sigsetsize))
2660 return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
2665 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2667 int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
2671 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2673 if (from->si_code < 0)
2674 return __copy_to_user(to, from, sizeof(siginfo_t))
2677 * If you change siginfo_t structure, please be sure
2678 * this code is fixed accordingly.
2679 * Please remember to update the signalfd_copyinfo() function
2680 * inside fs/signalfd.c too, in case siginfo_t changes.
2681 * It should never copy any pad contained in the structure
2682 * to avoid security leaks, but must copy the generic
2683 * 3 ints plus the relevant union member.
2685 err = __put_user(from->si_signo, &to->si_signo);
2686 err |= __put_user(from->si_errno, &to->si_errno);
2687 err |= __put_user((short)from->si_code, &to->si_code);
2688 switch (from->si_code & __SI_MASK) {
2690 err |= __put_user(from->si_pid, &to->si_pid);
2691 err |= __put_user(from->si_uid, &to->si_uid);
2694 err |= __put_user(from->si_tid, &to->si_tid);
2695 err |= __put_user(from->si_overrun, &to->si_overrun);
2696 err |= __put_user(from->si_ptr, &to->si_ptr);
2699 err |= __put_user(from->si_band, &to->si_band);
2700 err |= __put_user(from->si_fd, &to->si_fd);
2703 err |= __put_user(from->si_addr, &to->si_addr);
2704 #ifdef __ARCH_SI_TRAPNO
2705 err |= __put_user(from->si_trapno, &to->si_trapno);
2707 #ifdef BUS_MCEERR_AO
2709 * Other callers might not initialize the si_lsb field,
2710 * so check explicitly for the right codes here.
2712 if (from->si_signo == SIGBUS &&
2713 (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
2714 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2717 if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) {
2718 err |= __put_user(from->si_lower, &to->si_lower);
2719 err |= __put_user(from->si_upper, &to->si_upper);
2724 err |= __put_user(from->si_pid, &to->si_pid);
2725 err |= __put_user(from->si_uid, &to->si_uid);
2726 err |= __put_user(from->si_status, &to->si_status);
2727 err |= __put_user(from->si_utime, &to->si_utime);
2728 err |= __put_user(from->si_stime, &to->si_stime);
2730 case __SI_RT: /* This is not generated by the kernel as of now. */
2731 case __SI_MESGQ: /* But this is */
2732 err |= __put_user(from->si_pid, &to->si_pid);
2733 err |= __put_user(from->si_uid, &to->si_uid);
2734 err |= __put_user(from->si_ptr, &to->si_ptr);
2736 #ifdef __ARCH_SIGSYS
2738 err |= __put_user(from->si_call_addr, &to->si_call_addr);
2739 err |= __put_user(from->si_syscall, &to->si_syscall);
2740 err |= __put_user(from->si_arch, &to->si_arch);
2743 default: /* this is just in case for now ... */
2744 err |= __put_user(from->si_pid, &to->si_pid);
2745 err |= __put_user(from->si_uid, &to->si_uid);
2754 * do_sigtimedwait - wait for queued signals specified in @which
2755 * @which: queued signals to wait for
2756 * @info: if non-null, the signal's siginfo is returned here
2757 * @ts: upper bound on process time suspension
2759 int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
2760 const struct timespec *ts)
2762 struct task_struct *tsk = current;
2763 long timeout = MAX_SCHEDULE_TIMEOUT;
2764 sigset_t mask = *which;
2768 if (!timespec_valid(ts))
2770 timeout = timespec_to_jiffies(ts);
2772 * We can be close to the next tick, add another one
2773 * to ensure we will wait at least the time asked for.
2775 if (ts->tv_sec || ts->tv_nsec)
2780 * Invert the set of allowed signals to get those we want to block.
2782 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
2785 spin_lock_irq(&tsk->sighand->siglock);
2786 sig = dequeue_signal(tsk, &mask, info);
2787 if (!sig && timeout) {
2789 * None ready, temporarily unblock those we're interested
2790 * while we are sleeping in so that we'll be awakened when
2791 * they arrive. Unblocking is always fine, we can avoid
2792 * set_current_blocked().
2794 tsk->real_blocked = tsk->blocked;
2795 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
2796 recalc_sigpending();
2797 spin_unlock_irq(&tsk->sighand->siglock);
2799 timeout = freezable_schedule_timeout_interruptible(timeout);
2801 spin_lock_irq(&tsk->sighand->siglock);
2802 __set_task_blocked(tsk, &tsk->real_blocked);
2803 sigemptyset(&tsk->real_blocked);
2804 sig = dequeue_signal(tsk, &mask, info);
2806 spin_unlock_irq(&tsk->sighand->siglock);
2810 return timeout ? -EINTR : -EAGAIN;
2814 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2816 * @uthese: queued signals to wait for
2817 * @uinfo: if non-null, the signal's siginfo is returned here
2818 * @uts: upper bound on process time suspension
2819 * @sigsetsize: size of sigset_t type
2821 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2822 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2830 /* XXX: Don't preclude handling different sized sigset_t's. */
2831 if (sigsetsize != sizeof(sigset_t))
2834 if (copy_from_user(&these, uthese, sizeof(these)))
2838 if (copy_from_user(&ts, uts, sizeof(ts)))
2842 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
2844 if (ret > 0 && uinfo) {
2845 if (copy_siginfo_to_user(uinfo, &info))
2853 * sys_kill - send a signal to a process
2854 * @pid: the PID of the process
2855 * @sig: signal to be sent
2857 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2859 struct siginfo info;
2861 info.si_signo = sig;
2863 info.si_code = SI_USER;
2864 info.si_pid = task_tgid_vnr(current);
2865 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2867 return kill_something_info(sig, &info, pid);
2871 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2873 struct task_struct *p;
2877 p = find_task_by_vpid(pid);
2878 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2879 error = check_kill_permission(sig, info, p);
2881 * The null signal is a permissions and process existence
2882 * probe. No signal is actually delivered.
2884 if (!error && sig) {
2885 error = do_send_sig_info(sig, info, p, false);
2887 * If lock_task_sighand() failed we pretend the task
2888 * dies after receiving the signal. The window is tiny,
2889 * and the signal is private anyway.
2891 if (unlikely(error == -ESRCH))
2900 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2902 struct siginfo info = {};
2904 info.si_signo = sig;
2906 info.si_code = SI_TKILL;
2907 info.si_pid = task_tgid_vnr(current);
2908 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2910 return do_send_specific(tgid, pid, sig, &info);
2914 * sys_tgkill - send signal to one specific thread
2915 * @tgid: the thread group ID of the thread
2916 * @pid: the PID of the thread
2917 * @sig: signal to be sent
2919 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2920 * exists but it's not belonging to the target process anymore. This
2921 * method solves the problem of threads exiting and PIDs getting reused.
2923 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2925 /* This is only valid for single tasks */
2926 if (pid <= 0 || tgid <= 0)
2929 return do_tkill(tgid, pid, sig);
2933 * sys_tkill - send signal to one specific task
2934 * @pid: the PID of the task
2935 * @sig: signal to be sent
2937 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2939 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
2941 /* This is only valid for single tasks */
2945 return do_tkill(0, pid, sig);
2948 static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
2950 /* Not even root can pretend to send signals from the kernel.
2951 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2953 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
2954 (task_pid_vnr(current) != pid))
2957 info->si_signo = sig;
2959 /* POSIX.1b doesn't mention process groups. */
2960 return kill_proc_info(sig, info, pid);
2964 * sys_rt_sigqueueinfo - send signal information to a signal
2965 * @pid: the PID of the thread
2966 * @sig: signal to be sent
2967 * @uinfo: signal info to be sent
2969 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
2970 siginfo_t __user *, uinfo)
2973 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2975 return do_rt_sigqueueinfo(pid, sig, &info);
2978 #ifdef CONFIG_COMPAT
2979 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
2982 struct compat_siginfo __user *, uinfo)
2984 siginfo_t info = {};
2985 int ret = copy_siginfo_from_user32(&info, uinfo);
2988 return do_rt_sigqueueinfo(pid, sig, &info);
2992 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
2994 /* This is only valid for single tasks */
2995 if (pid <= 0 || tgid <= 0)
2998 /* Not even root can pretend to send signals from the kernel.
2999 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3001 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3002 (task_pid_vnr(current) != pid))
3005 info->si_signo = sig;
3007 return do_send_specific(tgid, pid, sig, info);
3010 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3011 siginfo_t __user *, uinfo)
3015 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3018 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3021 #ifdef CONFIG_COMPAT
3022 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3026 struct compat_siginfo __user *, uinfo)
3028 siginfo_t info = {};
3030 if (copy_siginfo_from_user32(&info, uinfo))
3032 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3037 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3039 void kernel_sigaction(int sig, __sighandler_t action)
3041 spin_lock_irq(¤t->sighand->siglock);
3042 current->sighand->action[sig - 1].sa.sa_handler = action;
3043 if (action == SIG_IGN) {
3047 sigaddset(&mask, sig);
3049 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3050 flush_sigqueue_mask(&mask, ¤t->pending);
3051 recalc_sigpending();
3053 spin_unlock_irq(¤t->sighand->siglock);
3055 EXPORT_SYMBOL(kernel_sigaction);
3057 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3059 struct task_struct *p = current, *t;
3060 struct k_sigaction *k;
3063 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3066 k = &p->sighand->action[sig-1];
3068 spin_lock_irq(&p->sighand->siglock);
3073 sigdelsetmask(&act->sa.sa_mask,
3074 sigmask(SIGKILL) | sigmask(SIGSTOP));
3078 * "Setting a signal action to SIG_IGN for a signal that is
3079 * pending shall cause the pending signal to be discarded,
3080 * whether or not it is blocked."
3082 * "Setting a signal action to SIG_DFL for a signal that is
3083 * pending and whose default action is to ignore the signal
3084 * (for example, SIGCHLD), shall cause the pending signal to
3085 * be discarded, whether or not it is blocked"
3087 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3089 sigaddset(&mask, sig);
3090 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3091 for_each_thread(p, t)
3092 flush_sigqueue_mask(&mask, &t->pending);
3096 spin_unlock_irq(&p->sighand->siglock);
3101 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
3106 oss.ss_sp = (void __user *) current->sas_ss_sp;
3107 oss.ss_size = current->sas_ss_size;
3108 oss.ss_flags = sas_ss_flags(sp);
3116 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
3118 error = __get_user(ss_sp, &uss->ss_sp) |
3119 __get_user(ss_flags, &uss->ss_flags) |
3120 __get_user(ss_size, &uss->ss_size);
3125 if (on_sig_stack(sp))
3130 * Note - this code used to test ss_flags incorrectly:
3131 * old code may have been written using ss_flags==0
3132 * to mean ss_flags==SS_ONSTACK (as this was the only
3133 * way that worked) - this fix preserves that older
3136 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
3139 if (ss_flags == SS_DISABLE) {
3144 if (ss_size < MINSIGSTKSZ)
3148 current->sas_ss_sp = (unsigned long) ss_sp;
3149 current->sas_ss_size = ss_size;
3155 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
3157 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
3158 __put_user(oss.ss_size, &uoss->ss_size) |
3159 __put_user(oss.ss_flags, &uoss->ss_flags);
3165 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3167 return do_sigaltstack(uss, uoss, current_user_stack_pointer());
3170 int restore_altstack(const stack_t __user *uss)
3172 int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
3173 /* squash all but EFAULT for now */
3174 return err == -EFAULT ? err : 0;
3177 int __save_altstack(stack_t __user *uss, unsigned long sp)
3179 struct task_struct *t = current;
3180 return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3181 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3182 __put_user(t->sas_ss_size, &uss->ss_size);
3185 #ifdef CONFIG_COMPAT
3186 COMPAT_SYSCALL_DEFINE2(sigaltstack,
3187 const compat_stack_t __user *, uss_ptr,
3188 compat_stack_t __user *, uoss_ptr)
3195 compat_stack_t uss32;
3197 memset(&uss, 0, sizeof(stack_t));
3198 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
3200 uss.ss_sp = compat_ptr(uss32.ss_sp);
3201 uss.ss_flags = uss32.ss_flags;
3202 uss.ss_size = uss32.ss_size;
3206 ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
3207 (stack_t __force __user *) &uoss,
3208 compat_user_stack_pointer());
3210 if (ret >= 0 && uoss_ptr) {
3211 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
3212 __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
3213 __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
3214 __put_user(uoss.ss_size, &uoss_ptr->ss_size))
3220 int compat_restore_altstack(const compat_stack_t __user *uss)
3222 int err = compat_sys_sigaltstack(uss, NULL);
3223 /* squash all but -EFAULT for now */
3224 return err == -EFAULT ? err : 0;
3227 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
3229 struct task_struct *t = current;
3230 return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
3231 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3232 __put_user(t->sas_ss_size, &uss->ss_size);
3236 #ifdef __ARCH_WANT_SYS_SIGPENDING
3239 * sys_sigpending - examine pending signals
3240 * @set: where mask of pending signal is returned
3242 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
3244 return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
3249 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3251 * sys_sigprocmask - examine and change blocked signals
3252 * @how: whether to add, remove, or set signals
3253 * @nset: signals to add or remove (if non-null)
3254 * @oset: previous value of signal mask if non-null
3256 * Some platforms have their own version with special arguments;
3257 * others support only sys_rt_sigprocmask.
3260 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
3261 old_sigset_t __user *, oset)
3263 old_sigset_t old_set, new_set;
3264 sigset_t new_blocked;
3266 old_set = current->blocked.sig[0];
3269 if (copy_from_user(&new_set, nset, sizeof(*nset)))
3272 new_blocked = current->blocked;
3276 sigaddsetmask(&new_blocked, new_set);
3279 sigdelsetmask(&new_blocked, new_set);
3282 new_blocked.sig[0] = new_set;
3288 set_current_blocked(&new_blocked);
3292 if (copy_to_user(oset, &old_set, sizeof(*oset)))
3298 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3300 #ifndef CONFIG_ODD_RT_SIGACTION
3302 * sys_rt_sigaction - alter an action taken by a process
3303 * @sig: signal to be sent
3304 * @act: new sigaction
3305 * @oact: used to save the previous sigaction
3306 * @sigsetsize: size of sigset_t type
3308 SYSCALL_DEFINE4(rt_sigaction, int, sig,
3309 const struct sigaction __user *, act,
3310 struct sigaction __user *, oact,
3313 struct k_sigaction new_sa, old_sa;
3316 /* XXX: Don't preclude handling different sized sigset_t's. */
3317 if (sigsetsize != sizeof(sigset_t))
3321 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
3325 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
3328 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
3334 #ifdef CONFIG_COMPAT
3335 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
3336 const struct compat_sigaction __user *, act,
3337 struct compat_sigaction __user *, oact,
3338 compat_size_t, sigsetsize)
3340 struct k_sigaction new_ka, old_ka;
3341 compat_sigset_t mask;
3342 #ifdef __ARCH_HAS_SA_RESTORER
3343 compat_uptr_t restorer;
3347 /* XXX: Don't preclude handling different sized sigset_t's. */
3348 if (sigsetsize != sizeof(compat_sigset_t))
3352 compat_uptr_t handler;
3353 ret = get_user(handler, &act->sa_handler);
3354 new_ka.sa.sa_handler = compat_ptr(handler);
3355 #ifdef __ARCH_HAS_SA_RESTORER
3356 ret |= get_user(restorer, &act->sa_restorer);
3357 new_ka.sa.sa_restorer = compat_ptr(restorer);
3359 ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
3360 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
3363 sigset_from_compat(&new_ka.sa.sa_mask, &mask);
3366 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3368 sigset_to_compat(&mask, &old_ka.sa.sa_mask);
3369 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
3371 ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
3372 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
3373 #ifdef __ARCH_HAS_SA_RESTORER
3374 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3375 &oact->sa_restorer);
3381 #endif /* !CONFIG_ODD_RT_SIGACTION */
3383 #ifdef CONFIG_OLD_SIGACTION
3384 SYSCALL_DEFINE3(sigaction, int, sig,
3385 const struct old_sigaction __user *, act,
3386 struct old_sigaction __user *, oact)
3388 struct k_sigaction new_ka, old_ka;
3393 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3394 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
3395 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
3396 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3397 __get_user(mask, &act->sa_mask))
3399 #ifdef __ARCH_HAS_KA_RESTORER
3400 new_ka.ka_restorer = NULL;
3402 siginitset(&new_ka.sa.sa_mask, mask);
3405 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3408 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3409 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
3410 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
3411 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3412 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3419 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3420 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
3421 const struct compat_old_sigaction __user *, act,
3422 struct compat_old_sigaction __user *, oact)
3424 struct k_sigaction new_ka, old_ka;
3426 compat_old_sigset_t mask;
3427 compat_uptr_t handler, restorer;
3430 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3431 __get_user(handler, &act->sa_handler) ||
3432 __get_user(restorer, &act->sa_restorer) ||
3433 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3434 __get_user(mask, &act->sa_mask))
3437 #ifdef __ARCH_HAS_KA_RESTORER
3438 new_ka.ka_restorer = NULL;
3440 new_ka.sa.sa_handler = compat_ptr(handler);
3441 new_ka.sa.sa_restorer = compat_ptr(restorer);
3442 siginitset(&new_ka.sa.sa_mask, mask);
3445 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3448 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3449 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
3450 &oact->sa_handler) ||
3451 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3452 &oact->sa_restorer) ||
3453 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3454 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3461 #ifdef CONFIG_SGETMASK_SYSCALL
3464 * For backwards compatibility. Functionality superseded by sigprocmask.
3466 SYSCALL_DEFINE0(sgetmask)
3469 return current->blocked.sig[0];
3472 SYSCALL_DEFINE1(ssetmask, int, newmask)
3474 int old = current->blocked.sig[0];
3477 siginitset(&newset, newmask);
3478 set_current_blocked(&newset);
3482 #endif /* CONFIG_SGETMASK_SYSCALL */
3484 #ifdef __ARCH_WANT_SYS_SIGNAL
3486 * For backwards compatibility. Functionality superseded by sigaction.
3488 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
3490 struct k_sigaction new_sa, old_sa;
3493 new_sa.sa.sa_handler = handler;
3494 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
3495 sigemptyset(&new_sa.sa.sa_mask);
3497 ret = do_sigaction(sig, &new_sa, &old_sa);
3499 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
3501 #endif /* __ARCH_WANT_SYS_SIGNAL */
3503 #ifdef __ARCH_WANT_SYS_PAUSE
3505 SYSCALL_DEFINE0(pause)
3507 while (!signal_pending(current)) {
3508 __set_current_state(TASK_INTERRUPTIBLE);
3511 return -ERESTARTNOHAND;
3516 static int sigsuspend(sigset_t *set)
3518 current->saved_sigmask = current->blocked;
3519 set_current_blocked(set);
3521 __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 */