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 /* SIGKILL and SIGSTOP may not be sent to the global init */
75 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
78 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
79 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
82 /* Only allow kernel generated signals to this kthread */
83 if (unlikely((t->flags & PF_KTHREAD) &&
84 (handler == SIG_KTHREAD_KERNEL) && !force))
87 return sig_handler_ignored(handler, sig);
90 static int sig_ignored(struct task_struct *t, int sig, bool force)
93 * Blocked signals are never ignored, since the
94 * signal handler may change by the time it is
97 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
101 * Tracers may want to know about even ignored signal unless it
102 * is SIGKILL which can't be reported anyway but can be ignored
103 * by SIGNAL_UNKILLABLE task.
105 if (t->ptrace && sig != SIGKILL)
108 return sig_task_ignored(t, sig, force);
112 * Re-calculate pending state from the set of locally pending
113 * signals, globally pending signals, and blocked signals.
115 static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
120 switch (_NSIG_WORDS) {
122 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
123 ready |= signal->sig[i] &~ blocked->sig[i];
126 case 4: ready = signal->sig[3] &~ blocked->sig[3];
127 ready |= signal->sig[2] &~ blocked->sig[2];
128 ready |= signal->sig[1] &~ blocked->sig[1];
129 ready |= signal->sig[0] &~ blocked->sig[0];
132 case 2: ready = signal->sig[1] &~ blocked->sig[1];
133 ready |= signal->sig[0] &~ blocked->sig[0];
136 case 1: ready = signal->sig[0] &~ blocked->sig[0];
141 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
143 static int recalc_sigpending_tsk(struct task_struct *t)
145 if ((t->jobctl & JOBCTL_PENDING_MASK) ||
146 PENDING(&t->pending, &t->blocked) ||
147 PENDING(&t->signal->shared_pending, &t->blocked)) {
148 set_tsk_thread_flag(t, TIF_SIGPENDING);
152 * We must never clear the flag in another thread, or in current
153 * when it's possible the current syscall is returning -ERESTART*.
154 * So we don't clear it here, and only callers who know they should do.
160 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
161 * This is superfluous when called on current, the wakeup is a harmless no-op.
163 void recalc_sigpending_and_wake(struct task_struct *t)
165 if (recalc_sigpending_tsk(t))
166 signal_wake_up(t, 0);
169 void recalc_sigpending(void)
171 if (!recalc_sigpending_tsk(current) && !freezing(current))
172 clear_thread_flag(TIF_SIGPENDING);
176 /* Given the mask, find the first available signal that should be serviced. */
178 #define SYNCHRONOUS_MASK \
179 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
180 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
182 int next_signal(struct sigpending *pending, sigset_t *mask)
184 unsigned long i, *s, *m, x;
187 s = pending->signal.sig;
191 * Handle the first word specially: it contains the
192 * synchronous signals that need to be dequeued first.
196 if (x & SYNCHRONOUS_MASK)
197 x &= SYNCHRONOUS_MASK;
202 switch (_NSIG_WORDS) {
204 for (i = 1; i < _NSIG_WORDS; ++i) {
208 sig = ffz(~x) + i*_NSIG_BPW + 1;
217 sig = ffz(~x) + _NSIG_BPW + 1;
228 static inline void print_dropped_signal(int sig)
230 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
232 if (!print_fatal_signals)
235 if (!__ratelimit(&ratelimit_state))
238 printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
239 current->comm, current->pid, sig);
243 * task_set_jobctl_pending - set jobctl pending bits
245 * @mask: pending bits to set
247 * Clear @mask from @task->jobctl. @mask must be subset of
248 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
249 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
250 * cleared. If @task is already being killed or exiting, this function
254 * Must be called with @task->sighand->siglock held.
257 * %true if @mask is set, %false if made noop because @task was dying.
259 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
261 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
262 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
263 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
265 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
268 if (mask & JOBCTL_STOP_SIGMASK)
269 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
271 task->jobctl |= mask;
276 * task_clear_jobctl_trapping - clear jobctl trapping bit
279 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
280 * Clear it and wake up the ptracer. Note that we don't need any further
281 * locking. @task->siglock guarantees that @task->parent points to the
285 * Must be called with @task->sighand->siglock held.
287 void task_clear_jobctl_trapping(struct task_struct *task)
289 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
290 task->jobctl &= ~JOBCTL_TRAPPING;
291 smp_mb(); /* advised by wake_up_bit() */
292 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
297 * task_clear_jobctl_pending - clear jobctl pending bits
299 * @mask: pending bits to clear
301 * Clear @mask from @task->jobctl. @mask must be subset of
302 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
303 * STOP bits are cleared together.
305 * If clearing of @mask leaves no stop or trap pending, this function calls
306 * task_clear_jobctl_trapping().
309 * Must be called with @task->sighand->siglock held.
311 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
313 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
315 if (mask & JOBCTL_STOP_PENDING)
316 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
318 task->jobctl &= ~mask;
320 if (!(task->jobctl & JOBCTL_PENDING_MASK))
321 task_clear_jobctl_trapping(task);
325 * task_participate_group_stop - participate in a group stop
326 * @task: task participating in a group stop
328 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
329 * Group stop states are cleared and the group stop count is consumed if
330 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
331 * stop, the appropriate %SIGNAL_* flags are set.
334 * Must be called with @task->sighand->siglock held.
337 * %true if group stop completion should be notified to the parent, %false
340 static bool task_participate_group_stop(struct task_struct *task)
342 struct signal_struct *sig = task->signal;
343 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
345 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
347 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
352 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
353 sig->group_stop_count--;
356 * Tell the caller to notify completion iff we are entering into a
357 * fresh group stop. Read comment in do_signal_stop() for details.
359 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
360 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
367 * allocate a new signal queue record
368 * - this may be called without locks if and only if t == current, otherwise an
369 * appropriate lock must be held to stop the target task from exiting
371 static struct sigqueue *
372 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
374 struct sigqueue *q = NULL;
375 struct user_struct *user;
379 * Protect access to @t credentials. This can go away when all
380 * callers hold rcu read lock.
382 * NOTE! A pending signal will hold on to the user refcount,
383 * and we get/put the refcount only when the sigpending count
384 * changes from/to zero.
387 user = __task_cred(t)->user;
388 sigpending = atomic_inc_return(&user->sigpending);
393 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
394 q = kmem_cache_alloc(sigqueue_cachep, flags);
396 print_dropped_signal(sig);
399 if (unlikely(q == NULL)) {
400 if (atomic_dec_and_test(&user->sigpending))
403 INIT_LIST_HEAD(&q->list);
411 static void __sigqueue_free(struct sigqueue *q)
413 if (q->flags & SIGQUEUE_PREALLOC)
415 if (atomic_dec_and_test(&q->user->sigpending))
417 kmem_cache_free(sigqueue_cachep, q);
420 void flush_sigqueue(struct sigpending *queue)
424 sigemptyset(&queue->signal);
425 while (!list_empty(&queue->list)) {
426 q = list_entry(queue->list.next, struct sigqueue , list);
427 list_del_init(&q->list);
433 * Flush all pending signals for this kthread.
435 void flush_signals(struct task_struct *t)
439 spin_lock_irqsave(&t->sighand->siglock, flags);
440 clear_tsk_thread_flag(t, TIF_SIGPENDING);
441 flush_sigqueue(&t->pending);
442 flush_sigqueue(&t->signal->shared_pending);
443 spin_unlock_irqrestore(&t->sighand->siglock, flags);
446 static void __flush_itimer_signals(struct sigpending *pending)
448 sigset_t signal, retain;
449 struct sigqueue *q, *n;
451 signal = pending->signal;
452 sigemptyset(&retain);
454 list_for_each_entry_safe(q, n, &pending->list, list) {
455 int sig = q->info.si_signo;
457 if (likely(q->info.si_code != SI_TIMER)) {
458 sigaddset(&retain, sig);
460 sigdelset(&signal, sig);
461 list_del_init(&q->list);
466 sigorsets(&pending->signal, &signal, &retain);
469 void flush_itimer_signals(void)
471 struct task_struct *tsk = current;
474 spin_lock_irqsave(&tsk->sighand->siglock, flags);
475 __flush_itimer_signals(&tsk->pending);
476 __flush_itimer_signals(&tsk->signal->shared_pending);
477 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
480 void ignore_signals(struct task_struct *t)
484 for (i = 0; i < _NSIG; ++i)
485 t->sighand->action[i].sa.sa_handler = SIG_IGN;
491 * Flush all handlers for a task.
495 flush_signal_handlers(struct task_struct *t, int force_default)
498 struct k_sigaction *ka = &t->sighand->action[0];
499 for (i = _NSIG ; i != 0 ; i--) {
500 if (force_default || ka->sa.sa_handler != SIG_IGN)
501 ka->sa.sa_handler = SIG_DFL;
503 #ifdef __ARCH_HAS_SA_RESTORER
504 ka->sa.sa_restorer = NULL;
506 sigemptyset(&ka->sa.sa_mask);
511 int unhandled_signal(struct task_struct *tsk, int sig)
513 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
514 if (is_global_init(tsk))
516 if (handler != SIG_IGN && handler != SIG_DFL)
518 /* if ptraced, let the tracer determine */
522 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
525 struct sigqueue *q, *first = NULL;
528 * Collect the siginfo appropriate to this signal. Check if
529 * there is another siginfo for the same signal.
531 list_for_each_entry(q, &list->list, list) {
532 if (q->info.si_signo == sig) {
539 sigdelset(&list->signal, sig);
543 list_del_init(&first->list);
544 copy_siginfo(info, &first->info);
547 (first->flags & SIGQUEUE_PREALLOC) &&
548 (info->si_code == SI_TIMER) &&
549 (info->si_sys_private);
551 __sigqueue_free(first);
554 * Ok, it wasn't in the queue. This must be
555 * a fast-pathed signal or we must have been
556 * out of queue space. So zero out the info.
558 info->si_signo = sig;
560 info->si_code = SI_USER;
566 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
567 siginfo_t *info, bool *resched_timer)
569 int sig = next_signal(pending, mask);
572 collect_signal(sig, pending, info, resched_timer);
577 * Dequeue a signal and return the element to the caller, which is
578 * expected to free it.
580 * All callers have to hold the siglock.
582 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
584 bool resched_timer = false;
587 /* We only dequeue private signals from ourselves, we don't let
588 * signalfd steal them
590 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
592 signr = __dequeue_signal(&tsk->signal->shared_pending,
593 mask, info, &resched_timer);
597 * itimers are process shared and we restart periodic
598 * itimers in the signal delivery path to prevent DoS
599 * attacks in the high resolution timer case. This is
600 * compliant with the old way of self-restarting
601 * itimers, as the SIGALRM is a legacy signal and only
602 * queued once. Changing the restart behaviour to
603 * restart the timer in the signal dequeue path is
604 * reducing the timer noise on heavy loaded !highres
607 if (unlikely(signr == SIGALRM)) {
608 struct hrtimer *tmr = &tsk->signal->real_timer;
610 if (!hrtimer_is_queued(tmr) &&
611 tsk->signal->it_real_incr.tv64 != 0) {
612 hrtimer_forward(tmr, tmr->base->get_time(),
613 tsk->signal->it_real_incr);
614 hrtimer_restart(tmr);
623 if (unlikely(sig_kernel_stop(signr))) {
625 * Set a marker that we have dequeued a stop signal. Our
626 * caller might release the siglock and then the pending
627 * stop signal it is about to process is no longer in the
628 * pending bitmasks, but must still be cleared by a SIGCONT
629 * (and overruled by a SIGKILL). So those cases clear this
630 * shared flag after we've set it. Note that this flag may
631 * remain set after the signal we return is ignored or
632 * handled. That doesn't matter because its only purpose
633 * is to alert stop-signal processing code when another
634 * processor has come along and cleared the flag.
636 current->jobctl |= JOBCTL_STOP_DEQUEUED;
640 * Release the siglock to ensure proper locking order
641 * of timer locks outside of siglocks. Note, we leave
642 * irqs disabled here, since the posix-timers code is
643 * about to disable them again anyway.
645 spin_unlock(&tsk->sighand->siglock);
646 do_schedule_next_timer(info);
647 spin_lock(&tsk->sighand->siglock);
653 * Tell a process that it has a new active signal..
655 * NOTE! we rely on the previous spin_lock to
656 * lock interrupts for us! We can only be called with
657 * "siglock" held, and the local interrupt must
658 * have been disabled when that got acquired!
660 * No need to set need_resched since signal event passing
661 * goes through ->blocked
663 void signal_wake_up_state(struct task_struct *t, unsigned int state)
665 set_tsk_thread_flag(t, TIF_SIGPENDING);
667 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
668 * case. We don't check t->state here because there is a race with it
669 * executing another processor and just now entering stopped state.
670 * By using wake_up_state, we ensure the process will wake up and
671 * handle its death signal.
673 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
678 * Remove signals in mask from the pending set and queue.
679 * Returns 1 if any signals were found.
681 * All callers must be holding the siglock.
683 static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
685 struct sigqueue *q, *n;
688 sigandsets(&m, mask, &s->signal);
689 if (sigisemptyset(&m))
692 sigandnsets(&s->signal, &s->signal, mask);
693 list_for_each_entry_safe(q, n, &s->list, list) {
694 if (sigismember(mask, q->info.si_signo)) {
695 list_del_init(&q->list);
702 static inline int is_si_special(const struct siginfo *info)
704 return info <= SEND_SIG_FORCED;
707 static inline bool si_fromuser(const struct siginfo *info)
709 return info == SEND_SIG_NOINFO ||
710 (!is_si_special(info) && SI_FROMUSER(info));
713 static int dequeue_synchronous_signal(siginfo_t *info)
715 struct task_struct *tsk = current;
716 struct sigpending *pending = &tsk->pending;
717 struct sigqueue *q, *sync = NULL;
720 * Might a synchronous signal be in the queue?
722 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
726 * Return the first synchronous signal in the queue.
728 list_for_each_entry(q, &pending->list, list) {
729 /* Synchronous signals have a postive si_code */
730 if ((q->info.si_code > SI_USER) &&
731 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
739 * Check if there is another siginfo for the same signal.
741 list_for_each_entry_continue(q, &pending->list, list) {
742 if (q->info.si_signo == sync->info.si_signo)
746 sigdelset(&pending->signal, sync->info.si_signo);
749 list_del_init(&sync->list);
750 copy_siginfo(info, &sync->info);
751 __sigqueue_free(sync);
752 return info->si_signo;
756 * called with RCU read lock from check_kill_permission()
758 static int kill_ok_by_cred(struct task_struct *t)
760 const struct cred *cred = current_cred();
761 const struct cred *tcred = __task_cred(t);
763 if (uid_eq(cred->euid, tcred->suid) ||
764 uid_eq(cred->euid, tcred->uid) ||
765 uid_eq(cred->uid, tcred->suid) ||
766 uid_eq(cred->uid, tcred->uid))
769 if (ns_capable(tcred->user_ns, CAP_KILL))
776 * Bad permissions for sending the signal
777 * - the caller must hold the RCU read lock
779 static int check_kill_permission(int sig, struct siginfo *info,
780 struct task_struct *t)
785 if (!valid_signal(sig))
788 if (!si_fromuser(info))
791 error = audit_signal_info(sig, t); /* Let audit system see the signal */
795 if (!same_thread_group(current, t) &&
796 !kill_ok_by_cred(t)) {
799 sid = task_session(t);
801 * We don't return the error if sid == NULL. The
802 * task was unhashed, the caller must notice this.
804 if (!sid || sid == task_session(current))
811 return security_task_kill(t, info, sig, 0);
815 * ptrace_trap_notify - schedule trap to notify ptracer
816 * @t: tracee wanting to notify tracer
818 * This function schedules sticky ptrace trap which is cleared on the next
819 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
822 * If @t is running, STOP trap will be taken. If trapped for STOP and
823 * ptracer is listening for events, tracee is woken up so that it can
824 * re-trap for the new event. If trapped otherwise, STOP trap will be
825 * eventually taken without returning to userland after the existing traps
826 * are finished by PTRACE_CONT.
829 * Must be called with @task->sighand->siglock held.
831 static void ptrace_trap_notify(struct task_struct *t)
833 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
834 assert_spin_locked(&t->sighand->siglock);
836 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
837 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
841 * Handle magic process-wide effects of stop/continue signals. Unlike
842 * the signal actions, these happen immediately at signal-generation
843 * time regardless of blocking, ignoring, or handling. This does the
844 * actual continuing for SIGCONT, but not the actual stopping for stop
845 * signals. The process stop is done as a signal action for SIG_DFL.
847 * Returns true if the signal should be actually delivered, otherwise
848 * it should be dropped.
850 static bool prepare_signal(int sig, struct task_struct *p, bool force)
852 struct signal_struct *signal = p->signal;
853 struct task_struct *t;
856 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
857 if (!(signal->flags & SIGNAL_GROUP_EXIT))
858 return sig == SIGKILL;
860 * The process is in the middle of dying, nothing to do.
862 } else if (sig_kernel_stop(sig)) {
864 * This is a stop signal. Remove SIGCONT from all queues.
866 siginitset(&flush, sigmask(SIGCONT));
867 flush_sigqueue_mask(&flush, &signal->shared_pending);
868 for_each_thread(p, t)
869 flush_sigqueue_mask(&flush, &t->pending);
870 } else if (sig == SIGCONT) {
873 * Remove all stop signals from all queues, wake all threads.
875 siginitset(&flush, SIG_KERNEL_STOP_MASK);
876 flush_sigqueue_mask(&flush, &signal->shared_pending);
877 for_each_thread(p, t) {
878 flush_sigqueue_mask(&flush, &t->pending);
879 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
880 if (likely(!(t->ptrace & PT_SEIZED)))
881 wake_up_state(t, __TASK_STOPPED);
883 ptrace_trap_notify(t);
887 * Notify the parent with CLD_CONTINUED if we were stopped.
889 * If we were in the middle of a group stop, we pretend it
890 * was already finished, and then continued. Since SIGCHLD
891 * doesn't queue we report only CLD_STOPPED, as if the next
892 * CLD_CONTINUED was dropped.
895 if (signal->flags & SIGNAL_STOP_STOPPED)
896 why |= SIGNAL_CLD_CONTINUED;
897 else if (signal->group_stop_count)
898 why |= SIGNAL_CLD_STOPPED;
902 * The first thread which returns from do_signal_stop()
903 * will take ->siglock, notice SIGNAL_CLD_MASK, and
904 * notify its parent. See get_signal_to_deliver().
906 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
907 signal->group_stop_count = 0;
908 signal->group_exit_code = 0;
912 return !sig_ignored(p, sig, force);
916 * Test if P wants to take SIG. After we've checked all threads with this,
917 * it's equivalent to finding no threads not blocking SIG. Any threads not
918 * blocking SIG were ruled out because they are not running and already
919 * have pending signals. Such threads will dequeue from the shared queue
920 * as soon as they're available, so putting the signal on the shared queue
921 * will be equivalent to sending it to one such thread.
923 static inline int wants_signal(int sig, struct task_struct *p)
925 if (sigismember(&p->blocked, sig))
927 if (p->flags & PF_EXITING)
931 if (task_is_stopped_or_traced(p))
933 return task_curr(p) || !signal_pending(p);
936 static void complete_signal(int sig, struct task_struct *p, int group)
938 struct signal_struct *signal = p->signal;
939 struct task_struct *t;
942 * Now find a thread we can wake up to take the signal off the queue.
944 * If the main thread wants the signal, it gets first crack.
945 * Probably the least surprising to the average bear.
947 if (wants_signal(sig, p))
949 else if (!group || thread_group_empty(p))
951 * There is just one thread and it does not need to be woken.
952 * It will dequeue unblocked signals before it runs again.
957 * Otherwise try to find a suitable thread.
959 t = signal->curr_target;
960 while (!wants_signal(sig, t)) {
962 if (t == signal->curr_target)
964 * No thread needs to be woken.
965 * Any eligible threads will see
966 * the signal in the queue soon.
970 signal->curr_target = t;
974 * Found a killable thread. If the signal will be fatal,
975 * then start taking the whole group down immediately.
977 if (sig_fatal(p, sig) &&
978 !(signal->flags & SIGNAL_GROUP_EXIT) &&
979 !sigismember(&t->real_blocked, sig) &&
980 (sig == SIGKILL || !p->ptrace)) {
982 * This signal will be fatal to the whole group.
984 if (!sig_kernel_coredump(sig)) {
986 * Start a group exit and wake everybody up.
987 * This way we don't have other threads
988 * running and doing things after a slower
989 * thread has the fatal signal pending.
991 signal->flags = SIGNAL_GROUP_EXIT;
992 signal->group_exit_code = sig;
993 signal->group_stop_count = 0;
996 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
997 sigaddset(&t->pending.signal, SIGKILL);
998 signal_wake_up(t, 1);
999 } while_each_thread(p, t);
1005 * The signal is already in the shared-pending queue.
1006 * Tell the chosen thread to wake up and dequeue it.
1008 signal_wake_up(t, sig == SIGKILL);
1012 static inline int legacy_queue(struct sigpending *signals, int sig)
1014 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1017 #ifdef CONFIG_USER_NS
1018 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1020 if (current_user_ns() == task_cred_xxx(t, user_ns))
1023 if (SI_FROMKERNEL(info))
1027 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
1028 make_kuid(current_user_ns(), info->si_uid));
1032 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1038 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
1039 int group, int from_ancestor_ns)
1041 struct sigpending *pending;
1043 int override_rlimit;
1044 int ret = 0, result;
1046 assert_spin_locked(&t->sighand->siglock);
1048 result = TRACE_SIGNAL_IGNORED;
1049 if (!prepare_signal(sig, t,
1050 from_ancestor_ns || (info == SEND_SIG_PRIV) || (info == SEND_SIG_FORCED)))
1053 pending = group ? &t->signal->shared_pending : &t->pending;
1055 * Short-circuit ignored signals and support queuing
1056 * exactly one non-rt signal, so that we can get more
1057 * detailed information about the cause of the signal.
1059 result = TRACE_SIGNAL_ALREADY_PENDING;
1060 if (legacy_queue(pending, sig))
1063 result = TRACE_SIGNAL_DELIVERED;
1065 * fast-pathed signals for kernel-internal things like SIGSTOP
1068 if (info == SEND_SIG_FORCED)
1072 * Real-time signals must be queued if sent by sigqueue, or
1073 * some other real-time mechanism. It is implementation
1074 * defined whether kill() does so. We attempt to do so, on
1075 * the principle of least surprise, but since kill is not
1076 * allowed to fail with EAGAIN when low on memory we just
1077 * make sure at least one signal gets delivered and don't
1078 * pass on the info struct.
1081 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1083 override_rlimit = 0;
1085 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
1088 list_add_tail(&q->list, &pending->list);
1089 switch ((unsigned long) info) {
1090 case (unsigned long) SEND_SIG_NOINFO:
1091 q->info.si_signo = sig;
1092 q->info.si_errno = 0;
1093 q->info.si_code = SI_USER;
1094 q->info.si_pid = task_tgid_nr_ns(current,
1095 task_active_pid_ns(t));
1096 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1098 case (unsigned long) SEND_SIG_PRIV:
1099 q->info.si_signo = sig;
1100 q->info.si_errno = 0;
1101 q->info.si_code = SI_KERNEL;
1106 copy_siginfo(&q->info, info);
1107 if (from_ancestor_ns)
1112 userns_fixup_signal_uid(&q->info, t);
1114 } else if (!is_si_special(info)) {
1115 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1117 * Queue overflow, abort. We may abort if the
1118 * signal was rt and sent by user using something
1119 * other than kill().
1121 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1126 * This is a silent loss of information. We still
1127 * send the signal, but the *info bits are lost.
1129 result = TRACE_SIGNAL_LOSE_INFO;
1134 signalfd_notify(t, sig);
1135 sigaddset(&pending->signal, sig);
1136 complete_signal(sig, t, group);
1138 trace_signal_generate(sig, info, t, group, result);
1142 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
1145 int from_ancestor_ns = 0;
1147 #ifdef CONFIG_PID_NS
1148 from_ancestor_ns = si_fromuser(info) &&
1149 !task_pid_nr_ns(current, task_active_pid_ns(t));
1152 return __send_signal(sig, info, t, group, from_ancestor_ns);
1155 static void print_fatal_signal(int signr)
1157 struct pt_regs *regs = signal_pt_regs();
1158 printk(KERN_INFO "potentially unexpected fatal signal %d.\n", signr);
1160 #if defined(__i386__) && !defined(__arch_um__)
1161 printk(KERN_INFO "code at %08lx: ", regs->ip);
1164 for (i = 0; i < 16; i++) {
1167 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1169 printk(KERN_CONT "%02x ", insn);
1172 printk(KERN_CONT "\n");
1179 static int __init setup_print_fatal_signals(char *str)
1181 get_option (&str, &print_fatal_signals);
1186 __setup("print-fatal-signals=", setup_print_fatal_signals);
1189 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1191 return send_signal(sig, info, p, 1);
1195 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1197 return send_signal(sig, info, t, 0);
1200 int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1203 unsigned long flags;
1206 if (lock_task_sighand(p, &flags)) {
1207 ret = send_signal(sig, info, p, group);
1208 unlock_task_sighand(p, &flags);
1215 * Force a signal that the process can't ignore: if necessary
1216 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1218 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1219 * since we do not want to have a signal handler that was blocked
1220 * be invoked when user space had explicitly blocked it.
1222 * We don't want to have recursive SIGSEGV's etc, for example,
1223 * that is why we also clear SIGNAL_UNKILLABLE.
1226 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1228 unsigned long int flags;
1229 int ret, blocked, ignored;
1230 struct k_sigaction *action;
1232 spin_lock_irqsave(&t->sighand->siglock, flags);
1233 action = &t->sighand->action[sig-1];
1234 ignored = action->sa.sa_handler == SIG_IGN;
1235 blocked = sigismember(&t->blocked, sig);
1236 if (blocked || ignored) {
1237 action->sa.sa_handler = SIG_DFL;
1239 sigdelset(&t->blocked, sig);
1240 recalc_sigpending_and_wake(t);
1243 if (action->sa.sa_handler == SIG_DFL)
1244 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1245 ret = specific_send_sig_info(sig, info, t);
1246 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1252 * Nuke all other threads in the group.
1254 int zap_other_threads(struct task_struct *p)
1256 struct task_struct *t = p;
1259 p->signal->group_stop_count = 0;
1261 while_each_thread(p, t) {
1262 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1265 /* Don't bother with already dead threads */
1268 sigaddset(&t->pending.signal, SIGKILL);
1269 signal_wake_up(t, 1);
1275 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1276 unsigned long *flags)
1278 struct sighand_struct *sighand;
1282 * Disable interrupts early to avoid deadlocks.
1283 * See rcu_read_unlock() comment header for details.
1285 local_irq_save(*flags);
1287 sighand = rcu_dereference(tsk->sighand);
1288 if (unlikely(sighand == NULL)) {
1290 local_irq_restore(*flags);
1294 * This sighand can be already freed and even reused, but
1295 * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which
1296 * initializes ->siglock: this slab can't go away, it has
1297 * the same object type, ->siglock can't be reinitialized.
1299 * We need to ensure that tsk->sighand is still the same
1300 * after we take the lock, we can race with de_thread() or
1301 * __exit_signal(). In the latter case the next iteration
1302 * must see ->sighand == NULL.
1304 spin_lock(&sighand->siglock);
1305 if (likely(sighand == tsk->sighand)) {
1309 spin_unlock(&sighand->siglock);
1311 local_irq_restore(*flags);
1318 * send signal info to all the members of a group
1320 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1325 ret = check_kill_permission(sig, info, p);
1329 ret = do_send_sig_info(sig, info, p, true);
1335 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1336 * control characters do (^C, ^Z etc)
1337 * - the caller must hold at least a readlock on tasklist_lock
1339 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1341 struct task_struct *p = NULL;
1342 int retval, success;
1346 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1347 int err = group_send_sig_info(sig, info, p);
1350 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1351 return success ? 0 : retval;
1354 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1357 struct task_struct *p;
1361 p = pid_task(pid, PIDTYPE_PID);
1363 error = group_send_sig_info(sig, info, p);
1365 if (likely(!p || error != -ESRCH))
1369 * The task was unhashed in between, try again. If it
1370 * is dead, pid_task() will return NULL, if we race with
1371 * de_thread() it will find the new leader.
1376 int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1380 error = kill_pid_info(sig, info, find_vpid(pid));
1385 static int kill_as_cred_perm(const struct cred *cred,
1386 struct task_struct *target)
1388 const struct cred *pcred = __task_cred(target);
1389 if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
1390 !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid))
1395 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1396 int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
1397 const struct cred *cred, u32 secid)
1400 struct task_struct *p;
1401 unsigned long flags;
1403 if (!valid_signal(sig))
1407 p = pid_task(pid, PIDTYPE_PID);
1412 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
1416 ret = security_task_kill(p, info, sig, secid);
1421 if (lock_task_sighand(p, &flags)) {
1422 ret = __send_signal(sig, info, p, 1, 0);
1423 unlock_task_sighand(p, &flags);
1431 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
1434 * kill_something_info() interprets pid in interesting ways just like kill(2).
1436 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1437 * is probably wrong. Should make it like BSD or SYSV.
1440 static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
1446 ret = kill_pid_info(sig, info, find_vpid(pid));
1451 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1455 read_lock(&tasklist_lock);
1457 ret = __kill_pgrp_info(sig, info,
1458 pid ? find_vpid(-pid) : task_pgrp(current));
1460 int retval = 0, count = 0;
1461 struct task_struct * p;
1463 for_each_process(p) {
1464 if (task_pid_vnr(p) > 1 &&
1465 !same_thread_group(p, current)) {
1466 int err = group_send_sig_info(sig, info, p);
1472 ret = count ? retval : -ESRCH;
1474 read_unlock(&tasklist_lock);
1480 * These are for backward compatibility with the rest of the kernel source.
1483 int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1486 * Make sure legacy kernel users don't send in bad values
1487 * (normal paths check this in check_kill_permission).
1489 if (!valid_signal(sig))
1492 return do_send_sig_info(sig, info, p, false);
1495 #define __si_special(priv) \
1496 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1499 send_sig(int sig, struct task_struct *p, int priv)
1501 return send_sig_info(sig, __si_special(priv), p);
1505 force_sig(int sig, struct task_struct *p)
1507 force_sig_info(sig, SEND_SIG_PRIV, p);
1511 * When things go south during signal handling, we
1512 * will force a SIGSEGV. And if the signal that caused
1513 * the problem was already a SIGSEGV, we'll want to
1514 * make sure we don't even try to deliver the signal..
1517 force_sigsegv(int sig, struct task_struct *p)
1519 if (sig == SIGSEGV) {
1520 unsigned long flags;
1521 spin_lock_irqsave(&p->sighand->siglock, flags);
1522 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1523 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1525 force_sig(SIGSEGV, p);
1529 int kill_pgrp(struct pid *pid, int sig, int priv)
1533 read_lock(&tasklist_lock);
1534 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1535 read_unlock(&tasklist_lock);
1539 EXPORT_SYMBOL(kill_pgrp);
1541 int kill_pid(struct pid *pid, int sig, int priv)
1543 return kill_pid_info(sig, __si_special(priv), pid);
1545 EXPORT_SYMBOL(kill_pid);
1548 * These functions support sending signals using preallocated sigqueue
1549 * structures. This is needed "because realtime applications cannot
1550 * afford to lose notifications of asynchronous events, like timer
1551 * expirations or I/O completions". In the case of POSIX Timers
1552 * we allocate the sigqueue structure from the timer_create. If this
1553 * allocation fails we are able to report the failure to the application
1554 * with an EAGAIN error.
1556 struct sigqueue *sigqueue_alloc(void)
1558 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1561 q->flags |= SIGQUEUE_PREALLOC;
1566 void sigqueue_free(struct sigqueue *q)
1568 unsigned long flags;
1569 spinlock_t *lock = ¤t->sighand->siglock;
1571 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1573 * We must hold ->siglock while testing q->list
1574 * to serialize with collect_signal() or with
1575 * __exit_signal()->flush_sigqueue().
1577 spin_lock_irqsave(lock, flags);
1578 q->flags &= ~SIGQUEUE_PREALLOC;
1580 * If it is queued it will be freed when dequeued,
1581 * like the "regular" sigqueue.
1583 if (!list_empty(&q->list))
1585 spin_unlock_irqrestore(lock, flags);
1591 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1593 int sig = q->info.si_signo;
1594 struct sigpending *pending;
1595 unsigned long flags;
1598 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1601 if (!likely(lock_task_sighand(t, &flags)))
1604 ret = 1; /* the signal is ignored */
1605 result = TRACE_SIGNAL_IGNORED;
1606 if (!prepare_signal(sig, t, false))
1610 if (unlikely(!list_empty(&q->list))) {
1612 * If an SI_TIMER entry is already queue just increment
1613 * the overrun count.
1615 BUG_ON(q->info.si_code != SI_TIMER);
1616 q->info.si_overrun++;
1617 result = TRACE_SIGNAL_ALREADY_PENDING;
1620 q->info.si_overrun = 0;
1622 signalfd_notify(t, sig);
1623 pending = group ? &t->signal->shared_pending : &t->pending;
1624 list_add_tail(&q->list, &pending->list);
1625 sigaddset(&pending->signal, sig);
1626 complete_signal(sig, t, group);
1627 result = TRACE_SIGNAL_DELIVERED;
1629 trace_signal_generate(sig, &q->info, t, group, result);
1630 unlock_task_sighand(t, &flags);
1636 * Let a parent know about the death of a child.
1637 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1639 * Returns true if our parent ignored us and so we've switched to
1642 bool do_notify_parent(struct task_struct *tsk, int sig)
1644 struct siginfo info;
1645 unsigned long flags;
1646 struct sighand_struct *psig;
1647 bool autoreap = false;
1648 cputime_t utime, stime;
1652 /* do_notify_parent_cldstop should have been called instead. */
1653 BUG_ON(task_is_stopped_or_traced(tsk));
1655 BUG_ON(!tsk->ptrace &&
1656 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1658 if (sig != SIGCHLD) {
1660 * This is only possible if parent == real_parent.
1661 * Check if it has changed security domain.
1663 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
1667 info.si_signo = sig;
1670 * We are under tasklist_lock here so our parent is tied to
1671 * us and cannot change.
1673 * task_active_pid_ns will always return the same pid namespace
1674 * until a task passes through release_task.
1676 * write_lock() currently calls preempt_disable() which is the
1677 * same as rcu_read_lock(), but according to Oleg, this is not
1678 * correct to rely on this
1681 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1682 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1686 task_cputime(tsk, &utime, &stime);
1687 info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime);
1688 info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime);
1690 info.si_status = tsk->exit_code & 0x7f;
1691 if (tsk->exit_code & 0x80)
1692 info.si_code = CLD_DUMPED;
1693 else if (tsk->exit_code & 0x7f)
1694 info.si_code = CLD_KILLED;
1696 info.si_code = CLD_EXITED;
1697 info.si_status = tsk->exit_code >> 8;
1700 psig = tsk->parent->sighand;
1701 spin_lock_irqsave(&psig->siglock, flags);
1702 if (!tsk->ptrace && sig == SIGCHLD &&
1703 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1704 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1706 * We are exiting and our parent doesn't care. POSIX.1
1707 * defines special semantics for setting SIGCHLD to SIG_IGN
1708 * or setting the SA_NOCLDWAIT flag: we should be reaped
1709 * automatically and not left for our parent's wait4 call.
1710 * Rather than having the parent do it as a magic kind of
1711 * signal handler, we just set this to tell do_exit that we
1712 * can be cleaned up without becoming a zombie. Note that
1713 * we still call __wake_up_parent in this case, because a
1714 * blocked sys_wait4 might now return -ECHILD.
1716 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1717 * is implementation-defined: we do (if you don't want
1718 * it, just use SIG_IGN instead).
1721 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1724 if (valid_signal(sig) && sig)
1725 __group_send_sig_info(sig, &info, tsk->parent);
1726 __wake_up_parent(tsk, tsk->parent);
1727 spin_unlock_irqrestore(&psig->siglock, flags);
1733 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1734 * @tsk: task reporting the state change
1735 * @for_ptracer: the notification is for ptracer
1736 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1738 * Notify @tsk's parent that the stopped/continued state has changed. If
1739 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1740 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1743 * Must be called with tasklist_lock at least read locked.
1745 static void do_notify_parent_cldstop(struct task_struct *tsk,
1746 bool for_ptracer, int why)
1748 struct siginfo info;
1749 unsigned long flags;
1750 struct task_struct *parent;
1751 struct sighand_struct *sighand;
1752 cputime_t utime, stime;
1755 parent = tsk->parent;
1757 tsk = tsk->group_leader;
1758 parent = tsk->real_parent;
1761 info.si_signo = SIGCHLD;
1764 * see comment in do_notify_parent() about the following 4 lines
1767 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
1768 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
1771 task_cputime(tsk, &utime, &stime);
1772 info.si_utime = cputime_to_clock_t(utime);
1773 info.si_stime = cputime_to_clock_t(stime);
1778 info.si_status = SIGCONT;
1781 info.si_status = tsk->signal->group_exit_code & 0x7f;
1784 info.si_status = tsk->exit_code & 0x7f;
1790 sighand = parent->sighand;
1791 spin_lock_irqsave(&sighand->siglock, flags);
1792 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1793 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1794 __group_send_sig_info(SIGCHLD, &info, parent);
1796 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1798 __wake_up_parent(tsk, parent);
1799 spin_unlock_irqrestore(&sighand->siglock, flags);
1802 static inline int may_ptrace_stop(void)
1804 if (!likely(current->ptrace))
1807 * Are we in the middle of do_coredump?
1808 * If so and our tracer is also part of the coredump stopping
1809 * is a deadlock situation, and pointless because our tracer
1810 * is dead so don't allow us to stop.
1811 * If SIGKILL was already sent before the caller unlocked
1812 * ->siglock we must see ->core_state != NULL. Otherwise it
1813 * is safe to enter schedule().
1815 * This is almost outdated, a task with the pending SIGKILL can't
1816 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1817 * after SIGKILL was already dequeued.
1819 if (unlikely(current->mm->core_state) &&
1820 unlikely(current->mm == current->parent->mm))
1827 * This must be called with current->sighand->siglock held.
1829 * This should be the path for all ptrace stops.
1830 * We always set current->last_siginfo while stopped here.
1831 * That makes it a way to test a stopped process for
1832 * being ptrace-stopped vs being job-control-stopped.
1834 * If we actually decide not to stop at all because the tracer
1835 * is gone, we keep current->exit_code unless clear_code.
1837 static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
1838 __releases(¤t->sighand->siglock)
1839 __acquires(¤t->sighand->siglock)
1841 bool gstop_done = false;
1843 if (arch_ptrace_stop_needed(exit_code, info)) {
1845 * The arch code has something special to do before a
1846 * ptrace stop. This is allowed to block, e.g. for faults
1847 * on user stack pages. We can't keep the siglock while
1848 * calling arch_ptrace_stop, so we must release it now.
1849 * To preserve proper semantics, we must do this before
1850 * any signal bookkeeping like checking group_stop_count.
1852 spin_unlock_irq(¤t->sighand->siglock);
1853 arch_ptrace_stop(exit_code, info);
1854 spin_lock_irq(¤t->sighand->siglock);
1858 * We're committing to trapping. TRACED should be visible before
1859 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1860 * Also, transition to TRACED and updates to ->jobctl should be
1861 * atomic with respect to siglock and should be done after the arch
1862 * hook as siglock is released and regrabbed across it.
1863 * schedule() will not sleep if there is a pending signal that
1864 * can awaken the task.
1866 set_current_state(TASK_TRACED);
1868 current->last_siginfo = info;
1869 current->exit_code = exit_code;
1872 * If @why is CLD_STOPPED, we're trapping to participate in a group
1873 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1874 * across siglock relocks since INTERRUPT was scheduled, PENDING
1875 * could be clear now. We act as if SIGCONT is received after
1876 * TASK_TRACED is entered - ignore it.
1878 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
1879 gstop_done = task_participate_group_stop(current);
1881 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1882 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
1883 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
1884 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
1886 /* entering a trap, clear TRAPPING */
1887 task_clear_jobctl_trapping(current);
1889 spin_unlock_irq(¤t->sighand->siglock);
1890 read_lock(&tasklist_lock);
1891 if (may_ptrace_stop()) {
1893 * Notify parents of the stop.
1895 * While ptraced, there are two parents - the ptracer and
1896 * the real_parent of the group_leader. The ptracer should
1897 * know about every stop while the real parent is only
1898 * interested in the completion of group stop. The states
1899 * for the two don't interact with each other. Notify
1900 * separately unless they're gonna be duplicates.
1902 do_notify_parent_cldstop(current, true, why);
1903 if (gstop_done && ptrace_reparented(current))
1904 do_notify_parent_cldstop(current, false, why);
1907 * Don't want to allow preemption here, because
1908 * sys_ptrace() needs this task to be inactive.
1910 * XXX: implement read_unlock_no_resched().
1913 read_unlock(&tasklist_lock);
1914 preempt_enable_no_resched();
1915 freezable_schedule();
1918 * By the time we got the lock, our tracer went away.
1919 * Don't drop the lock yet, another tracer may come.
1921 * If @gstop_done, the ptracer went away between group stop
1922 * completion and here. During detach, it would have set
1923 * JOBCTL_STOP_PENDING on us and we'll re-enter
1924 * TASK_STOPPED in do_signal_stop() on return, so notifying
1925 * the real parent of the group stop completion is enough.
1928 do_notify_parent_cldstop(current, false, why);
1930 /* tasklist protects us from ptrace_freeze_traced() */
1931 __set_current_state(TASK_RUNNING);
1933 current->exit_code = 0;
1934 read_unlock(&tasklist_lock);
1938 * We are back. Now reacquire the siglock before touching
1939 * last_siginfo, so that we are sure to have synchronized with
1940 * any signal-sending on another CPU that wants to examine it.
1942 spin_lock_irq(¤t->sighand->siglock);
1943 current->last_siginfo = NULL;
1945 /* LISTENING can be set only during STOP traps, clear it */
1946 current->jobctl &= ~JOBCTL_LISTENING;
1949 * Queued signals ignored us while we were stopped for tracing.
1950 * So check for any that we should take before resuming user mode.
1951 * This sets TIF_SIGPENDING, but never clears it.
1953 recalc_sigpending_tsk(current);
1956 static void ptrace_do_notify(int signr, int exit_code, int why)
1960 memset(&info, 0, sizeof info);
1961 info.si_signo = signr;
1962 info.si_code = exit_code;
1963 info.si_pid = task_pid_vnr(current);
1964 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1966 /* Let the debugger run. */
1967 ptrace_stop(exit_code, why, 1, &info);
1970 void ptrace_notify(int exit_code)
1972 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1973 if (unlikely(current->task_works))
1976 spin_lock_irq(¤t->sighand->siglock);
1977 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
1978 spin_unlock_irq(¤t->sighand->siglock);
1982 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1983 * @signr: signr causing group stop if initiating
1985 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1986 * and participate in it. If already set, participate in the existing
1987 * group stop. If participated in a group stop (and thus slept), %true is
1988 * returned with siglock released.
1990 * If ptraced, this function doesn't handle stop itself. Instead,
1991 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1992 * untouched. The caller must ensure that INTERRUPT trap handling takes
1993 * places afterwards.
1996 * Must be called with @current->sighand->siglock held, which is released
2000 * %false if group stop is already cancelled or ptrace trap is scheduled.
2001 * %true if participated in group stop.
2003 static bool do_signal_stop(int signr)
2004 __releases(¤t->sighand->siglock)
2006 struct signal_struct *sig = current->signal;
2008 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2009 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2010 struct task_struct *t;
2012 /* signr will be recorded in task->jobctl for retries */
2013 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2015 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2016 unlikely(signal_group_exit(sig)))
2019 * There is no group stop already in progress. We must
2022 * While ptraced, a task may be resumed while group stop is
2023 * still in effect and then receive a stop signal and
2024 * initiate another group stop. This deviates from the
2025 * usual behavior as two consecutive stop signals can't
2026 * cause two group stops when !ptraced. That is why we
2027 * also check !task_is_stopped(t) below.
2029 * The condition can be distinguished by testing whether
2030 * SIGNAL_STOP_STOPPED is already set. Don't generate
2031 * group_exit_code in such case.
2033 * This is not necessary for SIGNAL_STOP_CONTINUED because
2034 * an intervening stop signal is required to cause two
2035 * continued events regardless of ptrace.
2037 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2038 sig->group_exit_code = signr;
2040 sig->group_stop_count = 0;
2042 if (task_set_jobctl_pending(current, signr | gstop))
2043 sig->group_stop_count++;
2046 while_each_thread(current, t) {
2048 * Setting state to TASK_STOPPED for a group
2049 * stop is always done with the siglock held,
2050 * so this check has no races.
2052 if (!task_is_stopped(t) &&
2053 task_set_jobctl_pending(t, signr | gstop)) {
2054 sig->group_stop_count++;
2055 if (likely(!(t->ptrace & PT_SEIZED)))
2056 signal_wake_up(t, 0);
2058 ptrace_trap_notify(t);
2063 if (likely(!current->ptrace)) {
2067 * If there are no other threads in the group, or if there
2068 * is a group stop in progress and we are the last to stop,
2069 * report to the parent.
2071 if (task_participate_group_stop(current))
2072 notify = CLD_STOPPED;
2074 __set_current_state(TASK_STOPPED);
2075 spin_unlock_irq(¤t->sighand->siglock);
2078 * Notify the parent of the group stop completion. Because
2079 * we're not holding either the siglock or tasklist_lock
2080 * here, ptracer may attach inbetween; however, this is for
2081 * group stop and should always be delivered to the real
2082 * parent of the group leader. The new ptracer will get
2083 * its notification when this task transitions into
2087 read_lock(&tasklist_lock);
2088 do_notify_parent_cldstop(current, false, notify);
2089 read_unlock(&tasklist_lock);
2092 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2093 freezable_schedule();
2097 * While ptraced, group stop is handled by STOP trap.
2098 * Schedule it and let the caller deal with it.
2100 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2106 * do_jobctl_trap - take care of ptrace jobctl traps
2108 * When PT_SEIZED, it's used for both group stop and explicit
2109 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2110 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2111 * the stop signal; otherwise, %SIGTRAP.
2113 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2114 * number as exit_code and no siginfo.
2117 * Must be called with @current->sighand->siglock held, which may be
2118 * released and re-acquired before returning with intervening sleep.
2120 static void do_jobctl_trap(void)
2122 struct signal_struct *signal = current->signal;
2123 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2125 if (current->ptrace & PT_SEIZED) {
2126 if (!signal->group_stop_count &&
2127 !(signal->flags & SIGNAL_STOP_STOPPED))
2129 WARN_ON_ONCE(!signr);
2130 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2133 WARN_ON_ONCE(!signr);
2134 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2135 current->exit_code = 0;
2139 static int ptrace_signal(int signr, siginfo_t *info)
2141 ptrace_signal_deliver();
2143 * We do not check sig_kernel_stop(signr) but set this marker
2144 * unconditionally because we do not know whether debugger will
2145 * change signr. This flag has no meaning unless we are going
2146 * to stop after return from ptrace_stop(). In this case it will
2147 * be checked in do_signal_stop(), we should only stop if it was
2148 * not cleared by SIGCONT while we were sleeping. See also the
2149 * comment in dequeue_signal().
2151 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2152 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2154 /* We're back. Did the debugger cancel the sig? */
2155 signr = current->exit_code;
2159 current->exit_code = 0;
2162 * Update the siginfo structure if the signal has
2163 * changed. If the debugger wanted something
2164 * specific in the siginfo structure then it should
2165 * have updated *info via PTRACE_SETSIGINFO.
2167 if (signr != info->si_signo) {
2168 info->si_signo = signr;
2170 info->si_code = SI_USER;
2172 info->si_pid = task_pid_vnr(current->parent);
2173 info->si_uid = from_kuid_munged(current_user_ns(),
2174 task_uid(current->parent));
2178 /* If the (new) signal is now blocked, requeue it. */
2179 if (sigismember(¤t->blocked, signr)) {
2180 specific_send_sig_info(signr, info, current);
2187 int get_signal(struct ksignal *ksig)
2189 struct sighand_struct *sighand = current->sighand;
2190 struct signal_struct *signal = current->signal;
2193 if (unlikely(current->task_works))
2196 if (unlikely(uprobe_deny_signal()))
2200 * Do this once, we can't return to user-mode if freezing() == T.
2201 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2202 * thus do not need another check after return.
2207 spin_lock_irq(&sighand->siglock);
2209 * Every stopped thread goes here after wakeup. Check to see if
2210 * we should notify the parent, prepare_signal(SIGCONT) encodes
2211 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2213 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2216 if (signal->flags & SIGNAL_CLD_CONTINUED)
2217 why = CLD_CONTINUED;
2221 signal->flags &= ~SIGNAL_CLD_MASK;
2223 spin_unlock_irq(&sighand->siglock);
2226 * Notify the parent that we're continuing. This event is
2227 * always per-process and doesn't make whole lot of sense
2228 * for ptracers, who shouldn't consume the state via
2229 * wait(2) either, but, for backward compatibility, notify
2230 * the ptracer of the group leader too unless it's gonna be
2233 read_lock(&tasklist_lock);
2234 do_notify_parent_cldstop(current, false, why);
2236 if (ptrace_reparented(current->group_leader))
2237 do_notify_parent_cldstop(current->group_leader,
2239 read_unlock(&tasklist_lock);
2244 /* Has this task already been marked for death? */
2245 if (signal_group_exit(signal)) {
2246 ksig->info.si_signo = signr = SIGKILL;
2247 sigdelset(¤t->pending.signal, SIGKILL);
2248 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2249 &sighand->action[SIGKILL - 1]);
2250 recalc_sigpending();
2255 struct k_sigaction *ka;
2257 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2261 if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
2263 spin_unlock_irq(&sighand->siglock);
2268 * Signals generated by the execution of an instruction
2269 * need to be delivered before any other pending signals
2270 * so that the instruction pointer in the signal stack
2271 * frame points to the faulting instruction.
2273 signr = dequeue_synchronous_signal(&ksig->info);
2275 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2278 break; /* will return 0 */
2280 if (unlikely(current->ptrace) && signr != SIGKILL) {
2281 signr = ptrace_signal(signr, &ksig->info);
2286 ka = &sighand->action[signr-1];
2288 /* Trace actually delivered signals. */
2289 trace_signal_deliver(signr, &ksig->info, ka);
2291 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2293 if (ka->sa.sa_handler != SIG_DFL) {
2294 /* Run the handler. */
2297 if (ka->sa.sa_flags & SA_ONESHOT)
2298 ka->sa.sa_handler = SIG_DFL;
2300 break; /* will return non-zero "signr" value */
2304 * Now we are doing the default action for this signal.
2306 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2310 * Global init gets no signals it doesn't want.
2311 * Container-init gets no signals it doesn't want from same
2314 * Note that if global/container-init sees a sig_kernel_only()
2315 * signal here, the signal must have been generated internally
2316 * or must have come from an ancestor namespace. In either
2317 * case, the signal cannot be dropped.
2319 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2320 !sig_kernel_only(signr))
2323 if (sig_kernel_stop(signr)) {
2325 * The default action is to stop all threads in
2326 * the thread group. The job control signals
2327 * do nothing in an orphaned pgrp, but SIGSTOP
2328 * always works. Note that siglock needs to be
2329 * dropped during the call to is_orphaned_pgrp()
2330 * because of lock ordering with tasklist_lock.
2331 * This allows an intervening SIGCONT to be posted.
2332 * We need to check for that and bail out if necessary.
2334 if (signr != SIGSTOP) {
2335 spin_unlock_irq(&sighand->siglock);
2337 /* signals can be posted during this window */
2339 if (is_current_pgrp_orphaned())
2342 spin_lock_irq(&sighand->siglock);
2345 if (likely(do_signal_stop(ksig->info.si_signo))) {
2346 /* It released the siglock. */
2351 * We didn't actually stop, due to a race
2352 * with SIGCONT or something like that.
2358 spin_unlock_irq(&sighand->siglock);
2361 * Anything else is fatal, maybe with a core dump.
2363 current->flags |= PF_SIGNALED;
2365 if (sig_kernel_coredump(signr)) {
2366 if (print_fatal_signals)
2367 print_fatal_signal(ksig->info.si_signo);
2368 proc_coredump_connector(current);
2370 * If it was able to dump core, this kills all
2371 * other threads in the group and synchronizes with
2372 * their demise. If we lost the race with another
2373 * thread getting here, it set group_exit_code
2374 * first and our do_group_exit call below will use
2375 * that value and ignore the one we pass it.
2377 do_coredump(&ksig->info);
2381 * Death signals, no core dump.
2383 do_group_exit(ksig->info.si_signo);
2386 spin_unlock_irq(&sighand->siglock);
2389 return ksig->sig > 0;
2393 * signal_delivered -
2394 * @ksig: kernel signal struct
2395 * @stepping: nonzero if debugger single-step or block-step in use
2397 * This function should be called when a signal has successfully been
2398 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2399 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2400 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2402 static void signal_delivered(struct ksignal *ksig, int stepping)
2406 /* A signal was successfully delivered, and the
2407 saved sigmask was stored on the signal frame,
2408 and will be restored by sigreturn. So we can
2409 simply clear the restore sigmask flag. */
2410 clear_restore_sigmask();
2412 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2413 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2414 sigaddset(&blocked, ksig->sig);
2415 set_current_blocked(&blocked);
2416 tracehook_signal_handler(stepping);
2419 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2422 force_sigsegv(ksig->sig, current);
2424 signal_delivered(ksig, stepping);
2428 * It could be that complete_signal() picked us to notify about the
2429 * group-wide signal. Other threads should be notified now to take
2430 * the shared signals in @which since we will not.
2432 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2435 struct task_struct *t;
2437 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2438 if (sigisemptyset(&retarget))
2442 while_each_thread(tsk, t) {
2443 if (t->flags & PF_EXITING)
2446 if (!has_pending_signals(&retarget, &t->blocked))
2448 /* Remove the signals this thread can handle. */
2449 sigandsets(&retarget, &retarget, &t->blocked);
2451 if (!signal_pending(t))
2452 signal_wake_up(t, 0);
2454 if (sigisemptyset(&retarget))
2459 void exit_signals(struct task_struct *tsk)
2465 * @tsk is about to have PF_EXITING set - lock out users which
2466 * expect stable threadgroup.
2468 threadgroup_change_begin(tsk);
2470 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2471 tsk->flags |= PF_EXITING;
2472 threadgroup_change_end(tsk);
2476 spin_lock_irq(&tsk->sighand->siglock);
2478 * From now this task is not visible for group-wide signals,
2479 * see wants_signal(), do_signal_stop().
2481 tsk->flags |= PF_EXITING;
2483 threadgroup_change_end(tsk);
2485 if (!signal_pending(tsk))
2488 unblocked = tsk->blocked;
2489 signotset(&unblocked);
2490 retarget_shared_pending(tsk, &unblocked);
2492 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2493 task_participate_group_stop(tsk))
2494 group_stop = CLD_STOPPED;
2496 spin_unlock_irq(&tsk->sighand->siglock);
2499 * If group stop has completed, deliver the notification. This
2500 * should always go to the real parent of the group leader.
2502 if (unlikely(group_stop)) {
2503 read_lock(&tasklist_lock);
2504 do_notify_parent_cldstop(tsk, false, group_stop);
2505 read_unlock(&tasklist_lock);
2509 EXPORT_SYMBOL(recalc_sigpending);
2510 EXPORT_SYMBOL_GPL(dequeue_signal);
2511 EXPORT_SYMBOL(flush_signals);
2512 EXPORT_SYMBOL(force_sig);
2513 EXPORT_SYMBOL(send_sig);
2514 EXPORT_SYMBOL(send_sig_info);
2515 EXPORT_SYMBOL(sigprocmask);
2518 * System call entry points.
2522 * sys_restart_syscall - restart a system call
2524 SYSCALL_DEFINE0(restart_syscall)
2526 struct restart_block *restart = ¤t->restart_block;
2527 return restart->fn(restart);
2530 long do_no_restart_syscall(struct restart_block *param)
2535 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2537 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2538 sigset_t newblocked;
2539 /* A set of now blocked but previously unblocked signals. */
2540 sigandnsets(&newblocked, newset, ¤t->blocked);
2541 retarget_shared_pending(tsk, &newblocked);
2543 tsk->blocked = *newset;
2544 recalc_sigpending();
2548 * set_current_blocked - change current->blocked mask
2551 * It is wrong to change ->blocked directly, this helper should be used
2552 * to ensure the process can't miss a shared signal we are going to block.
2554 void set_current_blocked(sigset_t *newset)
2556 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2557 __set_current_blocked(newset);
2560 void __set_current_blocked(const sigset_t *newset)
2562 struct task_struct *tsk = current;
2565 * In case the signal mask hasn't changed, there is nothing we need
2566 * to do. The current->blocked shouldn't be modified by other task.
2568 if (sigequalsets(&tsk->blocked, newset))
2571 spin_lock_irq(&tsk->sighand->siglock);
2572 __set_task_blocked(tsk, newset);
2573 spin_unlock_irq(&tsk->sighand->siglock);
2577 * This is also useful for kernel threads that want to temporarily
2578 * (or permanently) block certain signals.
2580 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2581 * interface happily blocks "unblockable" signals like SIGKILL
2584 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2586 struct task_struct *tsk = current;
2589 /* Lockless, only current can change ->blocked, never from irq */
2591 *oldset = tsk->blocked;
2595 sigorsets(&newset, &tsk->blocked, set);
2598 sigandnsets(&newset, &tsk->blocked, set);
2607 __set_current_blocked(&newset);
2612 * sys_rt_sigprocmask - change the list of currently blocked signals
2613 * @how: whether to add, remove, or set signals
2614 * @nset: stores pending signals
2615 * @oset: previous value of signal mask if non-null
2616 * @sigsetsize: size of sigset_t type
2618 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2619 sigset_t __user *, oset, size_t, sigsetsize)
2621 sigset_t old_set, new_set;
2624 /* XXX: Don't preclude handling different sized sigset_t's. */
2625 if (sigsetsize != sizeof(sigset_t))
2628 old_set = current->blocked;
2631 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2633 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2635 error = sigprocmask(how, &new_set, NULL);
2641 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2648 #ifdef CONFIG_COMPAT
2649 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2650 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2653 sigset_t old_set = current->blocked;
2655 /* XXX: Don't preclude handling different sized sigset_t's. */
2656 if (sigsetsize != sizeof(sigset_t))
2660 compat_sigset_t new32;
2663 if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
2666 sigset_from_compat(&new_set, &new32);
2667 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2669 error = sigprocmask(how, &new_set, NULL);
2674 compat_sigset_t old32;
2675 sigset_to_compat(&old32, &old_set);
2676 if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
2681 return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
2682 (sigset_t __user *)oset, sigsetsize);
2687 static int do_sigpending(void *set, unsigned long sigsetsize)
2689 if (sigsetsize > sizeof(sigset_t))
2692 spin_lock_irq(¤t->sighand->siglock);
2693 sigorsets(set, ¤t->pending.signal,
2694 ¤t->signal->shared_pending.signal);
2695 spin_unlock_irq(¤t->sighand->siglock);
2697 /* Outside the lock because only this thread touches it. */
2698 sigandsets(set, ¤t->blocked, set);
2703 * sys_rt_sigpending - examine a pending signal that has been raised
2705 * @uset: stores pending signals
2706 * @sigsetsize: size of sigset_t type or larger
2708 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
2711 int err = do_sigpending(&set, sigsetsize);
2712 if (!err && copy_to_user(uset, &set, sigsetsize))
2717 #ifdef CONFIG_COMPAT
2718 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
2719 compat_size_t, sigsetsize)
2723 int err = do_sigpending(&set, sigsetsize);
2725 compat_sigset_t set32;
2726 sigset_to_compat(&set32, &set);
2727 /* we can get here only if sigsetsize <= sizeof(set) */
2728 if (copy_to_user(uset, &set32, sigsetsize))
2733 return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
2738 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2740 int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
2744 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2746 if (from->si_code < 0)
2747 return __copy_to_user(to, from, sizeof(siginfo_t))
2750 * If you change siginfo_t structure, please be sure
2751 * this code is fixed accordingly.
2752 * Please remember to update the signalfd_copyinfo() function
2753 * inside fs/signalfd.c too, in case siginfo_t changes.
2754 * It should never copy any pad contained in the structure
2755 * to avoid security leaks, but must copy the generic
2756 * 3 ints plus the relevant union member.
2758 err = __put_user(from->si_signo, &to->si_signo);
2759 err |= __put_user(from->si_errno, &to->si_errno);
2760 err |= __put_user((short)from->si_code, &to->si_code);
2761 switch (from->si_code & __SI_MASK) {
2763 err |= __put_user(from->si_pid, &to->si_pid);
2764 err |= __put_user(from->si_uid, &to->si_uid);
2767 err |= __put_user(from->si_tid, &to->si_tid);
2768 err |= __put_user(from->si_overrun, &to->si_overrun);
2769 err |= __put_user(from->si_ptr, &to->si_ptr);
2772 err |= __put_user(from->si_band, &to->si_band);
2773 err |= __put_user(from->si_fd, &to->si_fd);
2776 err |= __put_user(from->si_addr, &to->si_addr);
2777 #ifdef __ARCH_SI_TRAPNO
2778 err |= __put_user(from->si_trapno, &to->si_trapno);
2780 #ifdef BUS_MCEERR_AO
2782 * Other callers might not initialize the si_lsb field,
2783 * so check explicitly for the right codes here.
2785 if (from->si_signo == SIGBUS &&
2786 (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
2787 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2790 if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) {
2791 err |= __put_user(from->si_lower, &to->si_lower);
2792 err |= __put_user(from->si_upper, &to->si_upper);
2797 err |= __put_user(from->si_pid, &to->si_pid);
2798 err |= __put_user(from->si_uid, &to->si_uid);
2799 err |= __put_user(from->si_status, &to->si_status);
2800 err |= __put_user(from->si_utime, &to->si_utime);
2801 err |= __put_user(from->si_stime, &to->si_stime);
2803 case __SI_RT: /* This is not generated by the kernel as of now. */
2804 case __SI_MESGQ: /* But this is */
2805 err |= __put_user(from->si_pid, &to->si_pid);
2806 err |= __put_user(from->si_uid, &to->si_uid);
2807 err |= __put_user(from->si_ptr, &to->si_ptr);
2809 #ifdef __ARCH_SIGSYS
2811 err |= __put_user(from->si_call_addr, &to->si_call_addr);
2812 err |= __put_user(from->si_syscall, &to->si_syscall);
2813 err |= __put_user(from->si_arch, &to->si_arch);
2816 default: /* this is just in case for now ... */
2817 err |= __put_user(from->si_pid, &to->si_pid);
2818 err |= __put_user(from->si_uid, &to->si_uid);
2827 * do_sigtimedwait - wait for queued signals specified in @which
2828 * @which: queued signals to wait for
2829 * @info: if non-null, the signal's siginfo is returned here
2830 * @ts: upper bound on process time suspension
2832 int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
2833 const struct timespec *ts)
2835 struct task_struct *tsk = current;
2836 long timeout = MAX_SCHEDULE_TIMEOUT;
2837 sigset_t mask = *which;
2841 if (!timespec_valid(ts))
2843 timeout = timespec_to_jiffies(ts);
2845 * We can be close to the next tick, add another one
2846 * to ensure we will wait at least the time asked for.
2848 if (ts->tv_sec || ts->tv_nsec)
2853 * Invert the set of allowed signals to get those we want to block.
2855 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
2858 spin_lock_irq(&tsk->sighand->siglock);
2859 sig = dequeue_signal(tsk, &mask, info);
2860 if (!sig && timeout) {
2862 * None ready, temporarily unblock those we're interested
2863 * while we are sleeping in so that we'll be awakened when
2864 * they arrive. Unblocking is always fine, we can avoid
2865 * set_current_blocked().
2867 tsk->real_blocked = tsk->blocked;
2868 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
2869 recalc_sigpending();
2870 spin_unlock_irq(&tsk->sighand->siglock);
2872 timeout = freezable_schedule_timeout_interruptible(timeout);
2874 spin_lock_irq(&tsk->sighand->siglock);
2875 __set_task_blocked(tsk, &tsk->real_blocked);
2876 sigemptyset(&tsk->real_blocked);
2877 sig = dequeue_signal(tsk, &mask, info);
2879 spin_unlock_irq(&tsk->sighand->siglock);
2883 return timeout ? -EINTR : -EAGAIN;
2887 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2889 * @uthese: queued signals to wait for
2890 * @uinfo: if non-null, the signal's siginfo is returned here
2891 * @uts: upper bound on process time suspension
2892 * @sigsetsize: size of sigset_t type
2894 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2895 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2903 /* XXX: Don't preclude handling different sized sigset_t's. */
2904 if (sigsetsize != sizeof(sigset_t))
2907 if (copy_from_user(&these, uthese, sizeof(these)))
2911 if (copy_from_user(&ts, uts, sizeof(ts)))
2915 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
2917 if (ret > 0 && uinfo) {
2918 if (copy_siginfo_to_user(uinfo, &info))
2926 * sys_kill - send a signal to a process
2927 * @pid: the PID of the process
2928 * @sig: signal to be sent
2930 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2932 struct siginfo info;
2934 info.si_signo = sig;
2936 info.si_code = SI_USER;
2937 info.si_pid = task_tgid_vnr(current);
2938 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2940 return kill_something_info(sig, &info, pid);
2944 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2946 struct task_struct *p;
2950 p = find_task_by_vpid(pid);
2951 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2952 error = check_kill_permission(sig, info, p);
2954 * The null signal is a permissions and process existence
2955 * probe. No signal is actually delivered.
2957 if (!error && sig) {
2958 error = do_send_sig_info(sig, info, p, false);
2960 * If lock_task_sighand() failed we pretend the task
2961 * dies after receiving the signal. The window is tiny,
2962 * and the signal is private anyway.
2964 if (unlikely(error == -ESRCH))
2973 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2975 struct siginfo info = {};
2977 info.si_signo = sig;
2979 info.si_code = SI_TKILL;
2980 info.si_pid = task_tgid_vnr(current);
2981 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2983 return do_send_specific(tgid, pid, sig, &info);
2987 * sys_tgkill - send signal to one specific thread
2988 * @tgid: the thread group ID of the thread
2989 * @pid: the PID of the thread
2990 * @sig: signal to be sent
2992 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2993 * exists but it's not belonging to the target process anymore. This
2994 * method solves the problem of threads exiting and PIDs getting reused.
2996 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2998 /* This is only valid for single tasks */
2999 if (pid <= 0 || tgid <= 0)
3002 return do_tkill(tgid, pid, sig);
3006 * sys_tkill - send signal to one specific task
3007 * @pid: the PID of the task
3008 * @sig: signal to be sent
3010 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3012 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3014 /* This is only valid for single tasks */
3018 return do_tkill(0, pid, sig);
3021 static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
3023 /* Not even root can pretend to send signals from the kernel.
3024 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3026 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3027 (task_pid_vnr(current) != pid))
3030 info->si_signo = sig;
3032 /* POSIX.1b doesn't mention process groups. */
3033 return kill_proc_info(sig, info, pid);
3037 * sys_rt_sigqueueinfo - send signal information to a signal
3038 * @pid: the PID of the thread
3039 * @sig: signal to be sent
3040 * @uinfo: signal info to be sent
3042 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3043 siginfo_t __user *, uinfo)
3046 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3048 return do_rt_sigqueueinfo(pid, sig, &info);
3051 #ifdef CONFIG_COMPAT
3052 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3055 struct compat_siginfo __user *, uinfo)
3057 siginfo_t info = {};
3058 int ret = copy_siginfo_from_user32(&info, uinfo);
3061 return do_rt_sigqueueinfo(pid, sig, &info);
3065 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
3067 /* This is only valid for single tasks */
3068 if (pid <= 0 || tgid <= 0)
3071 /* Not even root can pretend to send signals from the kernel.
3072 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3074 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3075 (task_pid_vnr(current) != pid))
3078 info->si_signo = sig;
3080 return do_send_specific(tgid, pid, sig, info);
3083 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3084 siginfo_t __user *, uinfo)
3088 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3091 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3094 #ifdef CONFIG_COMPAT
3095 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3099 struct compat_siginfo __user *, uinfo)
3101 siginfo_t info = {};
3103 if (copy_siginfo_from_user32(&info, uinfo))
3105 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3110 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3112 void kernel_sigaction(int sig, __sighandler_t action)
3114 spin_lock_irq(¤t->sighand->siglock);
3115 current->sighand->action[sig - 1].sa.sa_handler = action;
3116 if (action == SIG_IGN) {
3120 sigaddset(&mask, sig);
3122 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3123 flush_sigqueue_mask(&mask, ¤t->pending);
3124 recalc_sigpending();
3126 spin_unlock_irq(¤t->sighand->siglock);
3128 EXPORT_SYMBOL(kernel_sigaction);
3130 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3132 struct task_struct *p = current, *t;
3133 struct k_sigaction *k;
3136 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3139 k = &p->sighand->action[sig-1];
3141 spin_lock_irq(&p->sighand->siglock);
3146 sigdelsetmask(&act->sa.sa_mask,
3147 sigmask(SIGKILL) | sigmask(SIGSTOP));
3151 * "Setting a signal action to SIG_IGN for a signal that is
3152 * pending shall cause the pending signal to be discarded,
3153 * whether or not it is blocked."
3155 * "Setting a signal action to SIG_DFL for a signal that is
3156 * pending and whose default action is to ignore the signal
3157 * (for example, SIGCHLD), shall cause the pending signal to
3158 * be discarded, whether or not it is blocked"
3160 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3162 sigaddset(&mask, sig);
3163 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3164 for_each_thread(p, t)
3165 flush_sigqueue_mask(&mask, &t->pending);
3169 spin_unlock_irq(&p->sighand->siglock);
3174 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
3179 oss.ss_sp = (void __user *) current->sas_ss_sp;
3180 oss.ss_size = current->sas_ss_size;
3181 oss.ss_flags = sas_ss_flags(sp);
3189 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
3191 error = __get_user(ss_sp, &uss->ss_sp) |
3192 __get_user(ss_flags, &uss->ss_flags) |
3193 __get_user(ss_size, &uss->ss_size);
3198 if (on_sig_stack(sp))
3203 * Note - this code used to test ss_flags incorrectly:
3204 * old code may have been written using ss_flags==0
3205 * to mean ss_flags==SS_ONSTACK (as this was the only
3206 * way that worked) - this fix preserves that older
3209 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
3212 if (ss_flags == SS_DISABLE) {
3217 if (ss_size < MINSIGSTKSZ)
3221 current->sas_ss_sp = (unsigned long) ss_sp;
3222 current->sas_ss_size = ss_size;
3228 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
3230 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
3231 __put_user(oss.ss_size, &uoss->ss_size) |
3232 __put_user(oss.ss_flags, &uoss->ss_flags);
3238 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3240 return do_sigaltstack(uss, uoss, current_user_stack_pointer());
3243 int restore_altstack(const stack_t __user *uss)
3245 int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
3246 /* squash all but EFAULT for now */
3247 return err == -EFAULT ? err : 0;
3250 int __save_altstack(stack_t __user *uss, unsigned long sp)
3252 struct task_struct *t = current;
3253 return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3254 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3255 __put_user(t->sas_ss_size, &uss->ss_size);
3258 #ifdef CONFIG_COMPAT
3259 COMPAT_SYSCALL_DEFINE2(sigaltstack,
3260 const compat_stack_t __user *, uss_ptr,
3261 compat_stack_t __user *, uoss_ptr)
3268 compat_stack_t uss32;
3270 memset(&uss, 0, sizeof(stack_t));
3271 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
3273 uss.ss_sp = compat_ptr(uss32.ss_sp);
3274 uss.ss_flags = uss32.ss_flags;
3275 uss.ss_size = uss32.ss_size;
3279 ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
3280 (stack_t __force __user *) &uoss,
3281 compat_user_stack_pointer());
3283 if (ret >= 0 && uoss_ptr) {
3284 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
3285 __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
3286 __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
3287 __put_user(uoss.ss_size, &uoss_ptr->ss_size))
3293 int compat_restore_altstack(const compat_stack_t __user *uss)
3295 int err = compat_sys_sigaltstack(uss, NULL);
3296 /* squash all but -EFAULT for now */
3297 return err == -EFAULT ? err : 0;
3300 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
3302 struct task_struct *t = current;
3303 return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
3304 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3305 __put_user(t->sas_ss_size, &uss->ss_size);
3309 #ifdef __ARCH_WANT_SYS_SIGPENDING
3312 * sys_sigpending - examine pending signals
3313 * @set: where mask of pending signal is returned
3315 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
3317 return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
3322 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3324 * sys_sigprocmask - examine and change blocked signals
3325 * @how: whether to add, remove, or set signals
3326 * @nset: signals to add or remove (if non-null)
3327 * @oset: previous value of signal mask if non-null
3329 * Some platforms have their own version with special arguments;
3330 * others support only sys_rt_sigprocmask.
3333 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
3334 old_sigset_t __user *, oset)
3336 old_sigset_t old_set, new_set;
3337 sigset_t new_blocked;
3339 old_set = current->blocked.sig[0];
3342 if (copy_from_user(&new_set, nset, sizeof(*nset)))
3345 new_blocked = current->blocked;
3349 sigaddsetmask(&new_blocked, new_set);
3352 sigdelsetmask(&new_blocked, new_set);
3355 new_blocked.sig[0] = new_set;
3361 set_current_blocked(&new_blocked);
3365 if (copy_to_user(oset, &old_set, sizeof(*oset)))
3371 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3373 #ifndef CONFIG_ODD_RT_SIGACTION
3375 * sys_rt_sigaction - alter an action taken by a process
3376 * @sig: signal to be sent
3377 * @act: new sigaction
3378 * @oact: used to save the previous sigaction
3379 * @sigsetsize: size of sigset_t type
3381 SYSCALL_DEFINE4(rt_sigaction, int, sig,
3382 const struct sigaction __user *, act,
3383 struct sigaction __user *, oact,
3386 struct k_sigaction new_sa, old_sa;
3389 /* XXX: Don't preclude handling different sized sigset_t's. */
3390 if (sigsetsize != sizeof(sigset_t))
3394 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
3398 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
3401 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
3407 #ifdef CONFIG_COMPAT
3408 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
3409 const struct compat_sigaction __user *, act,
3410 struct compat_sigaction __user *, oact,
3411 compat_size_t, sigsetsize)
3413 struct k_sigaction new_ka, old_ka;
3414 compat_sigset_t mask;
3415 #ifdef __ARCH_HAS_SA_RESTORER
3416 compat_uptr_t restorer;
3420 /* XXX: Don't preclude handling different sized sigset_t's. */
3421 if (sigsetsize != sizeof(compat_sigset_t))
3425 compat_uptr_t handler;
3426 ret = get_user(handler, &act->sa_handler);
3427 new_ka.sa.sa_handler = compat_ptr(handler);
3428 #ifdef __ARCH_HAS_SA_RESTORER
3429 ret |= get_user(restorer, &act->sa_restorer);
3430 new_ka.sa.sa_restorer = compat_ptr(restorer);
3432 ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
3433 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
3436 sigset_from_compat(&new_ka.sa.sa_mask, &mask);
3439 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3441 sigset_to_compat(&mask, &old_ka.sa.sa_mask);
3442 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
3444 ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
3445 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
3446 #ifdef __ARCH_HAS_SA_RESTORER
3447 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3448 &oact->sa_restorer);
3454 #endif /* !CONFIG_ODD_RT_SIGACTION */
3456 #ifdef CONFIG_OLD_SIGACTION
3457 SYSCALL_DEFINE3(sigaction, int, sig,
3458 const struct old_sigaction __user *, act,
3459 struct old_sigaction __user *, oact)
3461 struct k_sigaction new_ka, old_ka;
3466 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3467 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
3468 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
3469 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3470 __get_user(mask, &act->sa_mask))
3472 #ifdef __ARCH_HAS_KA_RESTORER
3473 new_ka.ka_restorer = NULL;
3475 siginitset(&new_ka.sa.sa_mask, mask);
3478 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3481 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3482 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
3483 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
3484 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3485 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3492 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3493 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
3494 const struct compat_old_sigaction __user *, act,
3495 struct compat_old_sigaction __user *, oact)
3497 struct k_sigaction new_ka, old_ka;
3499 compat_old_sigset_t mask;
3500 compat_uptr_t handler, restorer;
3503 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3504 __get_user(handler, &act->sa_handler) ||
3505 __get_user(restorer, &act->sa_restorer) ||
3506 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3507 __get_user(mask, &act->sa_mask))
3510 #ifdef __ARCH_HAS_KA_RESTORER
3511 new_ka.ka_restorer = NULL;
3513 new_ka.sa.sa_handler = compat_ptr(handler);
3514 new_ka.sa.sa_restorer = compat_ptr(restorer);
3515 siginitset(&new_ka.sa.sa_mask, mask);
3518 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3521 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3522 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
3523 &oact->sa_handler) ||
3524 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3525 &oact->sa_restorer) ||
3526 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3527 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3534 #ifdef CONFIG_SGETMASK_SYSCALL
3537 * For backwards compatibility. Functionality superseded by sigprocmask.
3539 SYSCALL_DEFINE0(sgetmask)
3542 return current->blocked.sig[0];
3545 SYSCALL_DEFINE1(ssetmask, int, newmask)
3547 int old = current->blocked.sig[0];
3550 siginitset(&newset, newmask);
3551 set_current_blocked(&newset);
3555 #endif /* CONFIG_SGETMASK_SYSCALL */
3557 #ifdef __ARCH_WANT_SYS_SIGNAL
3559 * For backwards compatibility. Functionality superseded by sigaction.
3561 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
3563 struct k_sigaction new_sa, old_sa;
3566 new_sa.sa.sa_handler = handler;
3567 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
3568 sigemptyset(&new_sa.sa.sa_mask);
3570 ret = do_sigaction(sig, &new_sa, &old_sa);
3572 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
3574 #endif /* __ARCH_WANT_SYS_SIGNAL */
3576 #ifdef __ARCH_WANT_SYS_PAUSE
3578 SYSCALL_DEFINE0(pause)
3580 while (!signal_pending(current)) {
3581 __set_current_state(TASK_INTERRUPTIBLE);
3584 return -ERESTARTNOHAND;
3589 static int sigsuspend(sigset_t *set)
3591 current->saved_sigmask = current->blocked;
3592 set_current_blocked(set);
3594 __set_current_state(TASK_INTERRUPTIBLE);
3596 set_restore_sigmask();
3597 return -ERESTARTNOHAND;
3601 * sys_rt_sigsuspend - replace the signal mask for a value with the
3602 * @unewset value until a signal is received
3603 * @unewset: new signal mask value
3604 * @sigsetsize: size of sigset_t type
3606 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
3610 /* XXX: Don't preclude handling different sized sigset_t's. */
3611 if (sigsetsize != sizeof(sigset_t))
3614 if (copy_from_user(&newset, unewset, sizeof(newset)))
3616 return sigsuspend(&newset);
3619 #ifdef CONFIG_COMPAT
3620 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
3624 compat_sigset_t newset32;
3626 /* XXX: Don't preclude handling different sized sigset_t's. */
3627 if (sigsetsize != sizeof(sigset_t))
3630 if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
3632 sigset_from_compat(&newset, &newset32);
3633 return sigsuspend(&newset);
3635 /* on little-endian bitmaps don't care about granularity */
3636 return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize);
3641 #ifdef CONFIG_OLD_SIGSUSPEND
3642 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
3645 siginitset(&blocked, mask);
3646 return sigsuspend(&blocked);
3649 #ifdef CONFIG_OLD_SIGSUSPEND3
3650 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
3653 siginitset(&blocked, mask);
3654 return sigsuspend(&blocked);
3658 __weak const char *arch_vma_name(struct vm_area_struct *vma)
3663 void __init signals_init(void)
3665 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
3668 #ifdef CONFIG_KGDB_KDB
3669 #include <linux/kdb.h>
3671 * kdb_send_sig_info - Allows kdb to send signals without exposing
3672 * signal internals. This function checks if the required locks are
3673 * available before calling the main signal code, to avoid kdb
3677 kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
3679 static struct task_struct *kdb_prev_t;
3681 if (!spin_trylock(&t->sighand->siglock)) {
3682 kdb_printf("Can't do kill command now.\n"
3683 "The sigmask lock is held somewhere else in "
3684 "kernel, try again later\n");
3687 spin_unlock(&t->sighand->siglock);
3688 new_t = kdb_prev_t != t;
3690 if (t->state != TASK_RUNNING && new_t) {
3691 kdb_printf("Process is not RUNNING, sending a signal from "
3692 "kdb risks deadlock\n"
3693 "on the run queue locks. "
3694 "The signal has _not_ been sent.\n"
3695 "Reissue the kill command if you want to risk "
3699 sig = info->si_signo;
3700 if (send_sig_info(sig, info, t))
3701 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3704 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
3706 #endif /* CONFIG_KGDB_KDB */