KEYS: add missing permission check for request_key() destination
[linux/fpc-iii.git] / kernel / signal.c
blob998e9f173c4588e8701e19895837cde1c1992009
1 /*
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>
17 #include <linux/fs.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)
70 void __user *handler;
72 handler = sig_handler(t, sig);
74 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
75 handler == SIG_DFL && !force)
76 return 1;
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
86 * unblocked.
88 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
89 return 0;
91 if (!sig_task_ignored(t, sig, force))
92 return 0;
95 * Tracers may want to know about even ignored signals.
97 return !t->ptrace;
101 * Re-calculate pending state from the set of locally pending
102 * signals, globally pending signals, and blocked signals.
104 static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
106 unsigned long ready;
107 long i;
109 switch (_NSIG_WORDS) {
110 default:
111 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
112 ready |= signal->sig[i] &~ blocked->sig[i];
113 break;
115 case 4: ready = signal->sig[3] &~ blocked->sig[3];
116 ready |= signal->sig[2] &~ blocked->sig[2];
117 ready |= signal->sig[1] &~ blocked->sig[1];
118 ready |= signal->sig[0] &~ blocked->sig[0];
119 break;
121 case 2: ready = signal->sig[1] &~ blocked->sig[1];
122 ready |= signal->sig[0] &~ blocked->sig[0];
123 break;
125 case 1: ready = signal->sig[0] &~ blocked->sig[0];
127 return ready != 0;
130 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
132 static int recalc_sigpending_tsk(struct task_struct *t)
134 if ((t->jobctl & JOBCTL_PENDING_MASK) ||
135 PENDING(&t->pending, &t->blocked) ||
136 PENDING(&t->signal->shared_pending, &t->blocked)) {
137 set_tsk_thread_flag(t, TIF_SIGPENDING);
138 return 1;
141 * We must never clear the flag in another thread, or in current
142 * when it's possible the current syscall is returning -ERESTART*.
143 * So we don't clear it here, and only callers who know they should do.
145 return 0;
149 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
150 * This is superfluous when called on current, the wakeup is a harmless no-op.
152 void recalc_sigpending_and_wake(struct task_struct *t)
154 if (recalc_sigpending_tsk(t))
155 signal_wake_up(t, 0);
158 void recalc_sigpending(void)
160 if (!recalc_sigpending_tsk(current) && !freezing(current))
161 clear_thread_flag(TIF_SIGPENDING);
165 /* Given the mask, find the first available signal that should be serviced. */
167 #define SYNCHRONOUS_MASK \
168 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
169 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
171 int next_signal(struct sigpending *pending, sigset_t *mask)
173 unsigned long i, *s, *m, x;
174 int sig = 0;
176 s = pending->signal.sig;
177 m = mask->sig;
180 * Handle the first word specially: it contains the
181 * synchronous signals that need to be dequeued first.
183 x = *s &~ *m;
184 if (x) {
185 if (x & SYNCHRONOUS_MASK)
186 x &= SYNCHRONOUS_MASK;
187 sig = ffz(~x) + 1;
188 return sig;
191 switch (_NSIG_WORDS) {
192 default:
193 for (i = 1; i < _NSIG_WORDS; ++i) {
194 x = *++s &~ *++m;
195 if (!x)
196 continue;
197 sig = ffz(~x) + i*_NSIG_BPW + 1;
198 break;
200 break;
202 case 2:
203 x = s[1] &~ m[1];
204 if (!x)
205 break;
206 sig = ffz(~x) + _NSIG_BPW + 1;
207 break;
209 case 1:
210 /* Nothing to do */
211 break;
214 return sig;
217 static inline void print_dropped_signal(int sig)
219 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
221 if (!print_fatal_signals)
222 return;
224 if (!__ratelimit(&ratelimit_state))
225 return;
227 printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
228 current->comm, current->pid, sig);
232 * task_set_jobctl_pending - set jobctl pending bits
233 * @task: target task
234 * @mask: pending bits to set
236 * Clear @mask from @task->jobctl. @mask must be subset of
237 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
238 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
239 * cleared. If @task is already being killed or exiting, this function
240 * becomes noop.
242 * CONTEXT:
243 * Must be called with @task->sighand->siglock held.
245 * RETURNS:
246 * %true if @mask is set, %false if made noop because @task was dying.
248 bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask)
250 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
251 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
252 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
254 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
255 return false;
257 if (mask & JOBCTL_STOP_SIGMASK)
258 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
260 task->jobctl |= mask;
261 return true;
265 * task_clear_jobctl_trapping - clear jobctl trapping bit
266 * @task: target task
268 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
269 * Clear it and wake up the ptracer. Note that we don't need any further
270 * locking. @task->siglock guarantees that @task->parent points to the
271 * ptracer.
273 * CONTEXT:
274 * Must be called with @task->sighand->siglock held.
276 void task_clear_jobctl_trapping(struct task_struct *task)
278 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
279 task->jobctl &= ~JOBCTL_TRAPPING;
280 smp_mb(); /* advised by wake_up_bit() */
281 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
286 * task_clear_jobctl_pending - clear jobctl pending bits
287 * @task: target task
288 * @mask: pending bits to clear
290 * Clear @mask from @task->jobctl. @mask must be subset of
291 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
292 * STOP bits are cleared together.
294 * If clearing of @mask leaves no stop or trap pending, this function calls
295 * task_clear_jobctl_trapping().
297 * CONTEXT:
298 * Must be called with @task->sighand->siglock held.
300 void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask)
302 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
304 if (mask & JOBCTL_STOP_PENDING)
305 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
307 task->jobctl &= ~mask;
309 if (!(task->jobctl & JOBCTL_PENDING_MASK))
310 task_clear_jobctl_trapping(task);
314 * task_participate_group_stop - participate in a group stop
315 * @task: task participating in a group stop
317 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
318 * Group stop states are cleared and the group stop count is consumed if
319 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
320 * stop, the appropriate %SIGNAL_* flags are set.
322 * CONTEXT:
323 * Must be called with @task->sighand->siglock held.
325 * RETURNS:
326 * %true if group stop completion should be notified to the parent, %false
327 * otherwise.
329 static bool task_participate_group_stop(struct task_struct *task)
331 struct signal_struct *sig = task->signal;
332 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
334 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
336 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
338 if (!consume)
339 return false;
341 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
342 sig->group_stop_count--;
345 * Tell the caller to notify completion iff we are entering into a
346 * fresh group stop. Read comment in do_signal_stop() for details.
348 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
349 sig->flags = SIGNAL_STOP_STOPPED;
350 return true;
352 return false;
356 * allocate a new signal queue record
357 * - this may be called without locks if and only if t == current, otherwise an
358 * appropriate lock must be held to stop the target task from exiting
360 static struct sigqueue *
361 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
363 struct sigqueue *q = NULL;
364 struct user_struct *user;
367 * Protect access to @t credentials. This can go away when all
368 * callers hold rcu read lock.
370 rcu_read_lock();
371 user = get_uid(__task_cred(t)->user);
372 atomic_inc(&user->sigpending);
373 rcu_read_unlock();
375 if (override_rlimit ||
376 atomic_read(&user->sigpending) <=
377 task_rlimit(t, RLIMIT_SIGPENDING)) {
378 q = kmem_cache_alloc(sigqueue_cachep, flags);
379 } else {
380 print_dropped_signal(sig);
383 if (unlikely(q == NULL)) {
384 atomic_dec(&user->sigpending);
385 free_uid(user);
386 } else {
387 INIT_LIST_HEAD(&q->list);
388 q->flags = 0;
389 q->user = user;
392 return q;
395 static void __sigqueue_free(struct sigqueue *q)
397 if (q->flags & SIGQUEUE_PREALLOC)
398 return;
399 atomic_dec(&q->user->sigpending);
400 free_uid(q->user);
401 kmem_cache_free(sigqueue_cachep, q);
404 void flush_sigqueue(struct sigpending *queue)
406 struct sigqueue *q;
408 sigemptyset(&queue->signal);
409 while (!list_empty(&queue->list)) {
410 q = list_entry(queue->list.next, struct sigqueue , list);
411 list_del_init(&q->list);
412 __sigqueue_free(q);
417 * Flush all pending signals for a task.
419 void __flush_signals(struct task_struct *t)
421 clear_tsk_thread_flag(t, TIF_SIGPENDING);
422 flush_sigqueue(&t->pending);
423 flush_sigqueue(&t->signal->shared_pending);
426 void flush_signals(struct task_struct *t)
428 unsigned long flags;
430 spin_lock_irqsave(&t->sighand->siglock, flags);
431 __flush_signals(t);
432 spin_unlock_irqrestore(&t->sighand->siglock, flags);
435 static void __flush_itimer_signals(struct sigpending *pending)
437 sigset_t signal, retain;
438 struct sigqueue *q, *n;
440 signal = pending->signal;
441 sigemptyset(&retain);
443 list_for_each_entry_safe(q, n, &pending->list, list) {
444 int sig = q->info.si_signo;
446 if (likely(q->info.si_code != SI_TIMER)) {
447 sigaddset(&retain, sig);
448 } else {
449 sigdelset(&signal, sig);
450 list_del_init(&q->list);
451 __sigqueue_free(q);
455 sigorsets(&pending->signal, &signal, &retain);
458 void flush_itimer_signals(void)
460 struct task_struct *tsk = current;
461 unsigned long flags;
463 spin_lock_irqsave(&tsk->sighand->siglock, flags);
464 __flush_itimer_signals(&tsk->pending);
465 __flush_itimer_signals(&tsk->signal->shared_pending);
466 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
469 void ignore_signals(struct task_struct *t)
471 int i;
473 for (i = 0; i < _NSIG; ++i)
474 t->sighand->action[i].sa.sa_handler = SIG_IGN;
476 flush_signals(t);
480 * Flush all handlers for a task.
483 void
484 flush_signal_handlers(struct task_struct *t, int force_default)
486 int i;
487 struct k_sigaction *ka = &t->sighand->action[0];
488 for (i = _NSIG ; i != 0 ; i--) {
489 if (force_default || ka->sa.sa_handler != SIG_IGN)
490 ka->sa.sa_handler = SIG_DFL;
491 ka->sa.sa_flags = 0;
492 #ifdef __ARCH_HAS_SA_RESTORER
493 ka->sa.sa_restorer = NULL;
494 #endif
495 sigemptyset(&ka->sa.sa_mask);
496 ka++;
500 int unhandled_signal(struct task_struct *tsk, int sig)
502 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
503 if (is_global_init(tsk))
504 return 1;
505 if (handler != SIG_IGN && handler != SIG_DFL)
506 return 0;
507 /* if ptraced, let the tracer determine */
508 return !tsk->ptrace;
512 * Notify the system that a driver wants to block all signals for this
513 * process, and wants to be notified if any signals at all were to be
514 * sent/acted upon. If the notifier routine returns non-zero, then the
515 * signal will be acted upon after all. If the notifier routine returns 0,
516 * then then signal will be blocked. Only one block per process is
517 * allowed. priv is a pointer to private data that the notifier routine
518 * can use to determine if the signal should be blocked or not.
520 void
521 block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
523 unsigned long flags;
525 spin_lock_irqsave(&current->sighand->siglock, flags);
526 current->notifier_mask = mask;
527 current->notifier_data = priv;
528 current->notifier = notifier;
529 spin_unlock_irqrestore(&current->sighand->siglock, flags);
532 /* Notify the system that blocking has ended. */
534 void
535 unblock_all_signals(void)
537 unsigned long flags;
539 spin_lock_irqsave(&current->sighand->siglock, flags);
540 current->notifier = NULL;
541 current->notifier_data = NULL;
542 recalc_sigpending();
543 spin_unlock_irqrestore(&current->sighand->siglock, flags);
546 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
547 bool *resched_timer)
549 struct sigqueue *q, *first = NULL;
552 * Collect the siginfo appropriate to this signal. Check if
553 * there is another siginfo for the same signal.
555 list_for_each_entry(q, &list->list, list) {
556 if (q->info.si_signo == sig) {
557 if (first)
558 goto still_pending;
559 first = q;
563 sigdelset(&list->signal, sig);
565 if (first) {
566 still_pending:
567 list_del_init(&first->list);
568 copy_siginfo(info, &first->info);
570 *resched_timer =
571 (first->flags & SIGQUEUE_PREALLOC) &&
572 (info->si_code == SI_TIMER) &&
573 (info->si_sys_private);
575 __sigqueue_free(first);
576 } else {
578 * Ok, it wasn't in the queue. This must be
579 * a fast-pathed signal or we must have been
580 * out of queue space. So zero out the info.
582 info->si_signo = sig;
583 info->si_errno = 0;
584 info->si_code = SI_USER;
585 info->si_pid = 0;
586 info->si_uid = 0;
590 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
591 siginfo_t *info, bool *resched_timer)
593 int sig = next_signal(pending, mask);
595 if (sig) {
596 if (current->notifier) {
597 if (sigismember(current->notifier_mask, sig)) {
598 if (!(current->notifier)(current->notifier_data)) {
599 clear_thread_flag(TIF_SIGPENDING);
600 return 0;
605 collect_signal(sig, pending, info, resched_timer);
608 return sig;
612 * Dequeue a signal and return the element to the caller, which is
613 * expected to free it.
615 * All callers have to hold the siglock.
617 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
619 bool resched_timer = false;
620 int signr;
622 /* We only dequeue private signals from ourselves, we don't let
623 * signalfd steal them
625 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
626 if (!signr) {
627 signr = __dequeue_signal(&tsk->signal->shared_pending,
628 mask, info, &resched_timer);
630 * itimer signal ?
632 * itimers are process shared and we restart periodic
633 * itimers in the signal delivery path to prevent DoS
634 * attacks in the high resolution timer case. This is
635 * compliant with the old way of self-restarting
636 * itimers, as the SIGALRM is a legacy signal and only
637 * queued once. Changing the restart behaviour to
638 * restart the timer in the signal dequeue path is
639 * reducing the timer noise on heavy loaded !highres
640 * systems too.
642 if (unlikely(signr == SIGALRM)) {
643 struct hrtimer *tmr = &tsk->signal->real_timer;
645 if (!hrtimer_is_queued(tmr) &&
646 tsk->signal->it_real_incr.tv64 != 0) {
647 hrtimer_forward(tmr, tmr->base->get_time(),
648 tsk->signal->it_real_incr);
649 hrtimer_restart(tmr);
654 recalc_sigpending();
655 if (!signr)
656 return 0;
658 if (unlikely(sig_kernel_stop(signr))) {
660 * Set a marker that we have dequeued a stop signal. Our
661 * caller might release the siglock and then the pending
662 * stop signal it is about to process is no longer in the
663 * pending bitmasks, but must still be cleared by a SIGCONT
664 * (and overruled by a SIGKILL). So those cases clear this
665 * shared flag after we've set it. Note that this flag may
666 * remain set after the signal we return is ignored or
667 * handled. That doesn't matter because its only purpose
668 * is to alert stop-signal processing code when another
669 * processor has come along and cleared the flag.
671 current->jobctl |= JOBCTL_STOP_DEQUEUED;
673 if (resched_timer) {
675 * Release the siglock to ensure proper locking order
676 * of timer locks outside of siglocks. Note, we leave
677 * irqs disabled here, since the posix-timers code is
678 * about to disable them again anyway.
680 spin_unlock(&tsk->sighand->siglock);
681 do_schedule_next_timer(info);
682 spin_lock(&tsk->sighand->siglock);
684 return signr;
688 * Tell a process that it has a new active signal..
690 * NOTE! we rely on the previous spin_lock to
691 * lock interrupts for us! We can only be called with
692 * "siglock" held, and the local interrupt must
693 * have been disabled when that got acquired!
695 * No need to set need_resched since signal event passing
696 * goes through ->blocked
698 void signal_wake_up_state(struct task_struct *t, unsigned int state)
700 set_tsk_thread_flag(t, TIF_SIGPENDING);
702 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
703 * case. We don't check t->state here because there is a race with it
704 * executing another processor and just now entering stopped state.
705 * By using wake_up_state, we ensure the process will wake up and
706 * handle its death signal.
708 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
709 kick_process(t);
713 * Remove signals in mask from the pending set and queue.
714 * Returns 1 if any signals were found.
716 * All callers must be holding the siglock.
718 static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
720 struct sigqueue *q, *n;
721 sigset_t m;
723 sigandsets(&m, mask, &s->signal);
724 if (sigisemptyset(&m))
725 return 0;
727 sigandnsets(&s->signal, &s->signal, mask);
728 list_for_each_entry_safe(q, n, &s->list, list) {
729 if (sigismember(mask, q->info.si_signo)) {
730 list_del_init(&q->list);
731 __sigqueue_free(q);
734 return 1;
737 static inline int is_si_special(const struct siginfo *info)
739 return info <= SEND_SIG_FORCED;
742 static inline bool si_fromuser(const struct siginfo *info)
744 return info == SEND_SIG_NOINFO ||
745 (!is_si_special(info) && SI_FROMUSER(info));
749 * called with RCU read lock from check_kill_permission()
751 static int kill_ok_by_cred(struct task_struct *t)
753 const struct cred *cred = current_cred();
754 const struct cred *tcred = __task_cred(t);
756 if (uid_eq(cred->euid, tcred->suid) ||
757 uid_eq(cred->euid, tcred->uid) ||
758 uid_eq(cred->uid, tcred->suid) ||
759 uid_eq(cred->uid, tcred->uid))
760 return 1;
762 if (ns_capable(tcred->user_ns, CAP_KILL))
763 return 1;
765 return 0;
769 * Bad permissions for sending the signal
770 * - the caller must hold the RCU read lock
772 static int check_kill_permission(int sig, struct siginfo *info,
773 struct task_struct *t)
775 struct pid *sid;
776 int error;
778 if (!valid_signal(sig))
779 return -EINVAL;
781 if (!si_fromuser(info))
782 return 0;
784 error = audit_signal_info(sig, t); /* Let audit system see the signal */
785 if (error)
786 return error;
788 if (!same_thread_group(current, t) &&
789 !kill_ok_by_cred(t)) {
790 switch (sig) {
791 case SIGCONT:
792 sid = task_session(t);
794 * We don't return the error if sid == NULL. The
795 * task was unhashed, the caller must notice this.
797 if (!sid || sid == task_session(current))
798 break;
799 default:
800 return -EPERM;
804 return security_task_kill(t, info, sig, 0);
808 * ptrace_trap_notify - schedule trap to notify ptracer
809 * @t: tracee wanting to notify tracer
811 * This function schedules sticky ptrace trap which is cleared on the next
812 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
813 * ptracer.
815 * If @t is running, STOP trap will be taken. If trapped for STOP and
816 * ptracer is listening for events, tracee is woken up so that it can
817 * re-trap for the new event. If trapped otherwise, STOP trap will be
818 * eventually taken without returning to userland after the existing traps
819 * are finished by PTRACE_CONT.
821 * CONTEXT:
822 * Must be called with @task->sighand->siglock held.
824 static void ptrace_trap_notify(struct task_struct *t)
826 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
827 assert_spin_locked(&t->sighand->siglock);
829 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
830 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
834 * Handle magic process-wide effects of stop/continue signals. Unlike
835 * the signal actions, these happen immediately at signal-generation
836 * time regardless of blocking, ignoring, or handling. This does the
837 * actual continuing for SIGCONT, but not the actual stopping for stop
838 * signals. The process stop is done as a signal action for SIG_DFL.
840 * Returns true if the signal should be actually delivered, otherwise
841 * it should be dropped.
843 static bool prepare_signal(int sig, struct task_struct *p, bool force)
845 struct signal_struct *signal = p->signal;
846 struct task_struct *t;
847 sigset_t flush;
849 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
850 if (signal->flags & SIGNAL_GROUP_COREDUMP)
851 return sig == SIGKILL;
853 * The process is in the middle of dying, nothing to do.
855 } else if (sig_kernel_stop(sig)) {
857 * This is a stop signal. Remove SIGCONT from all queues.
859 siginitset(&flush, sigmask(SIGCONT));
860 flush_sigqueue_mask(&flush, &signal->shared_pending);
861 for_each_thread(p, t)
862 flush_sigqueue_mask(&flush, &t->pending);
863 } else if (sig == SIGCONT) {
864 unsigned int why;
866 * Remove all stop signals from all queues, wake all threads.
868 siginitset(&flush, SIG_KERNEL_STOP_MASK);
869 flush_sigqueue_mask(&flush, &signal->shared_pending);
870 for_each_thread(p, t) {
871 flush_sigqueue_mask(&flush, &t->pending);
872 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
873 if (likely(!(t->ptrace & PT_SEIZED)))
874 wake_up_state(t, __TASK_STOPPED);
875 else
876 ptrace_trap_notify(t);
880 * Notify the parent with CLD_CONTINUED if we were stopped.
882 * If we were in the middle of a group stop, we pretend it
883 * was already finished, and then continued. Since SIGCHLD
884 * doesn't queue we report only CLD_STOPPED, as if the next
885 * CLD_CONTINUED was dropped.
887 why = 0;
888 if (signal->flags & SIGNAL_STOP_STOPPED)
889 why |= SIGNAL_CLD_CONTINUED;
890 else if (signal->group_stop_count)
891 why |= SIGNAL_CLD_STOPPED;
893 if (why) {
895 * The first thread which returns from do_signal_stop()
896 * will take ->siglock, notice SIGNAL_CLD_MASK, and
897 * notify its parent. See get_signal_to_deliver().
899 signal->flags = why | SIGNAL_STOP_CONTINUED;
900 signal->group_stop_count = 0;
901 signal->group_exit_code = 0;
905 return !sig_ignored(p, sig, force);
909 * Test if P wants to take SIG. After we've checked all threads with this,
910 * it's equivalent to finding no threads not blocking SIG. Any threads not
911 * blocking SIG were ruled out because they are not running and already
912 * have pending signals. Such threads will dequeue from the shared queue
913 * as soon as they're available, so putting the signal on the shared queue
914 * will be equivalent to sending it to one such thread.
916 static inline int wants_signal(int sig, struct task_struct *p)
918 if (sigismember(&p->blocked, sig))
919 return 0;
920 if (p->flags & PF_EXITING)
921 return 0;
922 if (sig == SIGKILL)
923 return 1;
924 if (task_is_stopped_or_traced(p))
925 return 0;
926 return task_curr(p) || !signal_pending(p);
929 static void complete_signal(int sig, struct task_struct *p, int group)
931 struct signal_struct *signal = p->signal;
932 struct task_struct *t;
935 * Now find a thread we can wake up to take the signal off the queue.
937 * If the main thread wants the signal, it gets first crack.
938 * Probably the least surprising to the average bear.
940 if (wants_signal(sig, p))
941 t = p;
942 else if (!group || thread_group_empty(p))
944 * There is just one thread and it does not need to be woken.
945 * It will dequeue unblocked signals before it runs again.
947 return;
948 else {
950 * Otherwise try to find a suitable thread.
952 t = signal->curr_target;
953 while (!wants_signal(sig, t)) {
954 t = next_thread(t);
955 if (t == signal->curr_target)
957 * No thread needs to be woken.
958 * Any eligible threads will see
959 * the signal in the queue soon.
961 return;
963 signal->curr_target = t;
967 * Found a killable thread. If the signal will be fatal,
968 * then start taking the whole group down immediately.
970 if (sig_fatal(p, sig) &&
971 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
972 !sigismember(&t->real_blocked, sig) &&
973 (sig == SIGKILL || !t->ptrace)) {
975 * This signal will be fatal to the whole group.
977 if (!sig_kernel_coredump(sig)) {
979 * Start a group exit and wake everybody up.
980 * This way we don't have other threads
981 * running and doing things after a slower
982 * thread has the fatal signal pending.
984 signal->flags = SIGNAL_GROUP_EXIT;
985 signal->group_exit_code = sig;
986 signal->group_stop_count = 0;
987 t = p;
988 do {
989 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
990 sigaddset(&t->pending.signal, SIGKILL);
991 signal_wake_up(t, 1);
992 } while_each_thread(p, t);
993 return;
998 * The signal is already in the shared-pending queue.
999 * Tell the chosen thread to wake up and dequeue it.
1001 signal_wake_up(t, sig == SIGKILL);
1002 return;
1005 static inline int legacy_queue(struct sigpending *signals, int sig)
1007 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1010 #ifdef CONFIG_USER_NS
1011 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1013 if (current_user_ns() == task_cred_xxx(t, user_ns))
1014 return;
1016 if (SI_FROMKERNEL(info))
1017 return;
1019 rcu_read_lock();
1020 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
1021 make_kuid(current_user_ns(), info->si_uid));
1022 rcu_read_unlock();
1024 #else
1025 static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1027 return;
1029 #endif
1031 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
1032 int group, int from_ancestor_ns)
1034 struct sigpending *pending;
1035 struct sigqueue *q;
1036 int override_rlimit;
1037 int ret = 0, result;
1039 assert_spin_locked(&t->sighand->siglock);
1041 result = TRACE_SIGNAL_IGNORED;
1042 if (!prepare_signal(sig, t,
1043 from_ancestor_ns || (info == SEND_SIG_FORCED)))
1044 goto ret;
1046 pending = group ? &t->signal->shared_pending : &t->pending;
1048 * Short-circuit ignored signals and support queuing
1049 * exactly one non-rt signal, so that we can get more
1050 * detailed information about the cause of the signal.
1052 result = TRACE_SIGNAL_ALREADY_PENDING;
1053 if (legacy_queue(pending, sig))
1054 goto ret;
1056 result = TRACE_SIGNAL_DELIVERED;
1058 * fast-pathed signals for kernel-internal things like SIGSTOP
1059 * or SIGKILL.
1061 if (info == SEND_SIG_FORCED)
1062 goto out_set;
1065 * Real-time signals must be queued if sent by sigqueue, or
1066 * some other real-time mechanism. It is implementation
1067 * defined whether kill() does so. We attempt to do so, on
1068 * the principle of least surprise, but since kill is not
1069 * allowed to fail with EAGAIN when low on memory we just
1070 * make sure at least one signal gets delivered and don't
1071 * pass on the info struct.
1073 if (sig < SIGRTMIN)
1074 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1075 else
1076 override_rlimit = 0;
1078 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
1079 override_rlimit);
1080 if (q) {
1081 list_add_tail(&q->list, &pending->list);
1082 switch ((unsigned long) info) {
1083 case (unsigned long) SEND_SIG_NOINFO:
1084 q->info.si_signo = sig;
1085 q->info.si_errno = 0;
1086 q->info.si_code = SI_USER;
1087 q->info.si_pid = task_tgid_nr_ns(current,
1088 task_active_pid_ns(t));
1089 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1090 break;
1091 case (unsigned long) SEND_SIG_PRIV:
1092 q->info.si_signo = sig;
1093 q->info.si_errno = 0;
1094 q->info.si_code = SI_KERNEL;
1095 q->info.si_pid = 0;
1096 q->info.si_uid = 0;
1097 break;
1098 default:
1099 copy_siginfo(&q->info, info);
1100 if (from_ancestor_ns)
1101 q->info.si_pid = 0;
1102 break;
1105 userns_fixup_signal_uid(&q->info, t);
1107 } else if (!is_si_special(info)) {
1108 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1110 * Queue overflow, abort. We may abort if the
1111 * signal was rt and sent by user using something
1112 * other than kill().
1114 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1115 ret = -EAGAIN;
1116 goto ret;
1117 } else {
1119 * This is a silent loss of information. We still
1120 * send the signal, but the *info bits are lost.
1122 result = TRACE_SIGNAL_LOSE_INFO;
1126 out_set:
1127 signalfd_notify(t, sig);
1128 sigaddset(&pending->signal, sig);
1129 complete_signal(sig, t, group);
1130 ret:
1131 trace_signal_generate(sig, info, t, group, result);
1132 return ret;
1135 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
1136 int group)
1138 int from_ancestor_ns = 0;
1140 #ifdef CONFIG_PID_NS
1141 from_ancestor_ns = si_fromuser(info) &&
1142 !task_pid_nr_ns(current, task_active_pid_ns(t));
1143 #endif
1145 return __send_signal(sig, info, t, group, from_ancestor_ns);
1148 static void print_fatal_signal(int signr)
1150 struct pt_regs *regs = signal_pt_regs();
1151 printk(KERN_INFO "potentially unexpected fatal signal %d.\n", signr);
1153 #if defined(__i386__) && !defined(__arch_um__)
1154 printk(KERN_INFO "code at %08lx: ", regs->ip);
1156 int i;
1157 for (i = 0; i < 16; i++) {
1158 unsigned char insn;
1160 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1161 break;
1162 printk(KERN_CONT "%02x ", insn);
1165 printk(KERN_CONT "\n");
1166 #endif
1167 preempt_disable();
1168 show_regs(regs);
1169 preempt_enable();
1172 static int __init setup_print_fatal_signals(char *str)
1174 get_option (&str, &print_fatal_signals);
1176 return 1;
1179 __setup("print-fatal-signals=", setup_print_fatal_signals);
1182 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1184 return send_signal(sig, info, p, 1);
1187 static int
1188 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1190 return send_signal(sig, info, t, 0);
1193 int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1194 bool group)
1196 unsigned long flags;
1197 int ret = -ESRCH;
1199 if (lock_task_sighand(p, &flags)) {
1200 ret = send_signal(sig, info, p, group);
1201 unlock_task_sighand(p, &flags);
1204 return ret;
1208 * Force a signal that the process can't ignore: if necessary
1209 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1211 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1212 * since we do not want to have a signal handler that was blocked
1213 * be invoked when user space had explicitly blocked it.
1215 * We don't want to have recursive SIGSEGV's etc, for example,
1216 * that is why we also clear SIGNAL_UNKILLABLE.
1219 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1221 unsigned long int flags;
1222 int ret, blocked, ignored;
1223 struct k_sigaction *action;
1225 spin_lock_irqsave(&t->sighand->siglock, flags);
1226 action = &t->sighand->action[sig-1];
1227 ignored = action->sa.sa_handler == SIG_IGN;
1228 blocked = sigismember(&t->blocked, sig);
1229 if (blocked || ignored) {
1230 action->sa.sa_handler = SIG_DFL;
1231 if (blocked) {
1232 sigdelset(&t->blocked, sig);
1233 recalc_sigpending_and_wake(t);
1236 if (action->sa.sa_handler == SIG_DFL)
1237 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1238 ret = specific_send_sig_info(sig, info, t);
1239 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1241 return ret;
1245 * Nuke all other threads in the group.
1247 int zap_other_threads(struct task_struct *p)
1249 struct task_struct *t = p;
1250 int count = 0;
1252 p->signal->group_stop_count = 0;
1254 while_each_thread(p, t) {
1255 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1256 count++;
1258 /* Don't bother with already dead threads */
1259 if (t->exit_state)
1260 continue;
1261 sigaddset(&t->pending.signal, SIGKILL);
1262 signal_wake_up(t, 1);
1265 return count;
1268 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1269 unsigned long *flags)
1271 struct sighand_struct *sighand;
1273 for (;;) {
1274 local_irq_save(*flags);
1275 rcu_read_lock();
1276 sighand = rcu_dereference(tsk->sighand);
1277 if (unlikely(sighand == NULL)) {
1278 rcu_read_unlock();
1279 local_irq_restore(*flags);
1280 break;
1283 spin_lock(&sighand->siglock);
1284 if (likely(sighand == tsk->sighand)) {
1285 rcu_read_unlock();
1286 break;
1288 spin_unlock(&sighand->siglock);
1289 rcu_read_unlock();
1290 local_irq_restore(*flags);
1293 return sighand;
1297 * send signal info to all the members of a group
1299 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1301 int ret;
1303 rcu_read_lock();
1304 ret = check_kill_permission(sig, info, p);
1305 rcu_read_unlock();
1307 if (!ret && sig)
1308 ret = do_send_sig_info(sig, info, p, true);
1310 return ret;
1314 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1315 * control characters do (^C, ^Z etc)
1316 * - the caller must hold at least a readlock on tasklist_lock
1318 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1320 struct task_struct *p = NULL;
1321 int retval, success;
1323 success = 0;
1324 retval = -ESRCH;
1325 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1326 int err = group_send_sig_info(sig, info, p);
1327 success |= !err;
1328 retval = err;
1329 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1330 return success ? 0 : retval;
1333 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1335 int error = -ESRCH;
1336 struct task_struct *p;
1338 rcu_read_lock();
1339 retry:
1340 p = pid_task(pid, PIDTYPE_PID);
1341 if (p) {
1342 error = group_send_sig_info(sig, info, p);
1343 if (unlikely(error == -ESRCH))
1345 * The task was unhashed in between, try again.
1346 * If it is dead, pid_task() will return NULL,
1347 * if we race with de_thread() it will find the
1348 * new leader.
1350 goto retry;
1352 rcu_read_unlock();
1354 return error;
1357 int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1359 int error;
1360 rcu_read_lock();
1361 error = kill_pid_info(sig, info, find_vpid(pid));
1362 rcu_read_unlock();
1363 return error;
1366 static int kill_as_cred_perm(const struct cred *cred,
1367 struct task_struct *target)
1369 const struct cred *pcred = __task_cred(target);
1370 if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
1371 !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid))
1372 return 0;
1373 return 1;
1376 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1377 int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
1378 const struct cred *cred, u32 secid)
1380 int ret = -EINVAL;
1381 struct task_struct *p;
1382 unsigned long flags;
1384 if (!valid_signal(sig))
1385 return ret;
1387 rcu_read_lock();
1388 p = pid_task(pid, PIDTYPE_PID);
1389 if (!p) {
1390 ret = -ESRCH;
1391 goto out_unlock;
1393 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
1394 ret = -EPERM;
1395 goto out_unlock;
1397 ret = security_task_kill(p, info, sig, secid);
1398 if (ret)
1399 goto out_unlock;
1401 if (sig) {
1402 if (lock_task_sighand(p, &flags)) {
1403 ret = __send_signal(sig, info, p, 1, 0);
1404 unlock_task_sighand(p, &flags);
1405 } else
1406 ret = -ESRCH;
1408 out_unlock:
1409 rcu_read_unlock();
1410 return ret;
1412 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
1415 * kill_something_info() interprets pid in interesting ways just like kill(2).
1417 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1418 * is probably wrong. Should make it like BSD or SYSV.
1421 static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
1423 int ret;
1425 if (pid > 0) {
1426 rcu_read_lock();
1427 ret = kill_pid_info(sig, info, find_vpid(pid));
1428 rcu_read_unlock();
1429 return ret;
1432 read_lock(&tasklist_lock);
1433 if (pid != -1) {
1434 ret = __kill_pgrp_info(sig, info,
1435 pid ? find_vpid(-pid) : task_pgrp(current));
1436 } else {
1437 int retval = 0, count = 0;
1438 struct task_struct * p;
1440 for_each_process(p) {
1441 if (task_pid_vnr(p) > 1 &&
1442 !same_thread_group(p, current)) {
1443 int err = group_send_sig_info(sig, info, p);
1444 ++count;
1445 if (err != -EPERM)
1446 retval = err;
1449 ret = count ? retval : -ESRCH;
1451 read_unlock(&tasklist_lock);
1453 return ret;
1457 * These are for backward compatibility with the rest of the kernel source.
1460 int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1463 * Make sure legacy kernel users don't send in bad values
1464 * (normal paths check this in check_kill_permission).
1466 if (!valid_signal(sig))
1467 return -EINVAL;
1469 return do_send_sig_info(sig, info, p, false);
1472 #define __si_special(priv) \
1473 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1476 send_sig(int sig, struct task_struct *p, int priv)
1478 return send_sig_info(sig, __si_special(priv), p);
1481 void
1482 force_sig(int sig, struct task_struct *p)
1484 force_sig_info(sig, SEND_SIG_PRIV, p);
1488 * When things go south during signal handling, we
1489 * will force a SIGSEGV. And if the signal that caused
1490 * the problem was already a SIGSEGV, we'll want to
1491 * make sure we don't even try to deliver the signal..
1494 force_sigsegv(int sig, struct task_struct *p)
1496 if (sig == SIGSEGV) {
1497 unsigned long flags;
1498 spin_lock_irqsave(&p->sighand->siglock, flags);
1499 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1500 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1502 force_sig(SIGSEGV, p);
1503 return 0;
1506 int kill_pgrp(struct pid *pid, int sig, int priv)
1508 int ret;
1510 read_lock(&tasklist_lock);
1511 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1512 read_unlock(&tasklist_lock);
1514 return ret;
1516 EXPORT_SYMBOL(kill_pgrp);
1518 int kill_pid(struct pid *pid, int sig, int priv)
1520 return kill_pid_info(sig, __si_special(priv), pid);
1522 EXPORT_SYMBOL(kill_pid);
1525 * These functions support sending signals using preallocated sigqueue
1526 * structures. This is needed "because realtime applications cannot
1527 * afford to lose notifications of asynchronous events, like timer
1528 * expirations or I/O completions". In the case of POSIX Timers
1529 * we allocate the sigqueue structure from the timer_create. If this
1530 * allocation fails we are able to report the failure to the application
1531 * with an EAGAIN error.
1533 struct sigqueue *sigqueue_alloc(void)
1535 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1537 if (q)
1538 q->flags |= SIGQUEUE_PREALLOC;
1540 return q;
1543 void sigqueue_free(struct sigqueue *q)
1545 unsigned long flags;
1546 spinlock_t *lock = &current->sighand->siglock;
1548 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1550 * We must hold ->siglock while testing q->list
1551 * to serialize with collect_signal() or with
1552 * __exit_signal()->flush_sigqueue().
1554 spin_lock_irqsave(lock, flags);
1555 q->flags &= ~SIGQUEUE_PREALLOC;
1557 * If it is queued it will be freed when dequeued,
1558 * like the "regular" sigqueue.
1560 if (!list_empty(&q->list))
1561 q = NULL;
1562 spin_unlock_irqrestore(lock, flags);
1564 if (q)
1565 __sigqueue_free(q);
1568 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1570 int sig = q->info.si_signo;
1571 struct sigpending *pending;
1572 unsigned long flags;
1573 int ret, result;
1575 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1577 ret = -1;
1578 if (!likely(lock_task_sighand(t, &flags)))
1579 goto ret;
1581 ret = 1; /* the signal is ignored */
1582 result = TRACE_SIGNAL_IGNORED;
1583 if (!prepare_signal(sig, t, false))
1584 goto out;
1586 ret = 0;
1587 if (unlikely(!list_empty(&q->list))) {
1589 * If an SI_TIMER entry is already queue just increment
1590 * the overrun count.
1592 BUG_ON(q->info.si_code != SI_TIMER);
1593 q->info.si_overrun++;
1594 result = TRACE_SIGNAL_ALREADY_PENDING;
1595 goto out;
1597 q->info.si_overrun = 0;
1599 signalfd_notify(t, sig);
1600 pending = group ? &t->signal->shared_pending : &t->pending;
1601 list_add_tail(&q->list, &pending->list);
1602 sigaddset(&pending->signal, sig);
1603 complete_signal(sig, t, group);
1604 result = TRACE_SIGNAL_DELIVERED;
1605 out:
1606 trace_signal_generate(sig, &q->info, t, group, result);
1607 unlock_task_sighand(t, &flags);
1608 ret:
1609 return ret;
1613 * Let a parent know about the death of a child.
1614 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1616 * Returns true if our parent ignored us and so we've switched to
1617 * self-reaping.
1619 bool do_notify_parent(struct task_struct *tsk, int sig)
1621 struct siginfo info;
1622 unsigned long flags;
1623 struct sighand_struct *psig;
1624 bool autoreap = false;
1625 cputime_t utime, stime;
1627 BUG_ON(sig == -1);
1629 /* do_notify_parent_cldstop should have been called instead. */
1630 BUG_ON(task_is_stopped_or_traced(tsk));
1632 BUG_ON(!tsk->ptrace &&
1633 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1635 if (sig != SIGCHLD) {
1637 * This is only possible if parent == real_parent.
1638 * Check if it has changed security domain.
1640 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1641 sig = SIGCHLD;
1644 info.si_signo = sig;
1645 info.si_errno = 0;
1647 * We are under tasklist_lock here so our parent is tied to
1648 * us and cannot change.
1650 * task_active_pid_ns will always return the same pid namespace
1651 * until a task passes through release_task.
1653 * write_lock() currently calls preempt_disable() which is the
1654 * same as rcu_read_lock(), but according to Oleg, this is not
1655 * correct to rely on this
1657 rcu_read_lock();
1658 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1659 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1660 task_uid(tsk));
1661 rcu_read_unlock();
1663 task_cputime(tsk, &utime, &stime);
1664 info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime);
1665 info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime);
1667 info.si_status = tsk->exit_code & 0x7f;
1668 if (tsk->exit_code & 0x80)
1669 info.si_code = CLD_DUMPED;
1670 else if (tsk->exit_code & 0x7f)
1671 info.si_code = CLD_KILLED;
1672 else {
1673 info.si_code = CLD_EXITED;
1674 info.si_status = tsk->exit_code >> 8;
1677 psig = tsk->parent->sighand;
1678 spin_lock_irqsave(&psig->siglock, flags);
1679 if (!tsk->ptrace && sig == SIGCHLD &&
1680 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1681 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1683 * We are exiting and our parent doesn't care. POSIX.1
1684 * defines special semantics for setting SIGCHLD to SIG_IGN
1685 * or setting the SA_NOCLDWAIT flag: we should be reaped
1686 * automatically and not left for our parent's wait4 call.
1687 * Rather than having the parent do it as a magic kind of
1688 * signal handler, we just set this to tell do_exit that we
1689 * can be cleaned up without becoming a zombie. Note that
1690 * we still call __wake_up_parent in this case, because a
1691 * blocked sys_wait4 might now return -ECHILD.
1693 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1694 * is implementation-defined: we do (if you don't want
1695 * it, just use SIG_IGN instead).
1697 autoreap = true;
1698 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1699 sig = 0;
1701 if (valid_signal(sig) && sig)
1702 __group_send_sig_info(sig, &info, tsk->parent);
1703 __wake_up_parent(tsk, tsk->parent);
1704 spin_unlock_irqrestore(&psig->siglock, flags);
1706 return autoreap;
1710 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1711 * @tsk: task reporting the state change
1712 * @for_ptracer: the notification is for ptracer
1713 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1715 * Notify @tsk's parent that the stopped/continued state has changed. If
1716 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1717 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1719 * CONTEXT:
1720 * Must be called with tasklist_lock at least read locked.
1722 static void do_notify_parent_cldstop(struct task_struct *tsk,
1723 bool for_ptracer, int why)
1725 struct siginfo info;
1726 unsigned long flags;
1727 struct task_struct *parent;
1728 struct sighand_struct *sighand;
1729 cputime_t utime, stime;
1731 if (for_ptracer) {
1732 parent = tsk->parent;
1733 } else {
1734 tsk = tsk->group_leader;
1735 parent = tsk->real_parent;
1738 info.si_signo = SIGCHLD;
1739 info.si_errno = 0;
1741 * see comment in do_notify_parent() about the following 4 lines
1743 rcu_read_lock();
1744 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
1745 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
1746 rcu_read_unlock();
1748 task_cputime(tsk, &utime, &stime);
1749 info.si_utime = cputime_to_clock_t(utime);
1750 info.si_stime = cputime_to_clock_t(stime);
1752 info.si_code = why;
1753 switch (why) {
1754 case CLD_CONTINUED:
1755 info.si_status = SIGCONT;
1756 break;
1757 case CLD_STOPPED:
1758 info.si_status = tsk->signal->group_exit_code & 0x7f;
1759 break;
1760 case CLD_TRAPPED:
1761 info.si_status = tsk->exit_code & 0x7f;
1762 break;
1763 default:
1764 BUG();
1767 sighand = parent->sighand;
1768 spin_lock_irqsave(&sighand->siglock, flags);
1769 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1770 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1771 __group_send_sig_info(SIGCHLD, &info, parent);
1773 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1775 __wake_up_parent(tsk, parent);
1776 spin_unlock_irqrestore(&sighand->siglock, flags);
1779 static inline int may_ptrace_stop(void)
1781 if (!likely(current->ptrace))
1782 return 0;
1784 * Are we in the middle of do_coredump?
1785 * If so and our tracer is also part of the coredump stopping
1786 * is a deadlock situation, and pointless because our tracer
1787 * is dead so don't allow us to stop.
1788 * If SIGKILL was already sent before the caller unlocked
1789 * ->siglock we must see ->core_state != NULL. Otherwise it
1790 * is safe to enter schedule().
1792 * This is almost outdated, a task with the pending SIGKILL can't
1793 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1794 * after SIGKILL was already dequeued.
1796 if (unlikely(current->mm->core_state) &&
1797 unlikely(current->mm == current->parent->mm))
1798 return 0;
1800 return 1;
1804 * Return non-zero if there is a SIGKILL that should be waking us up.
1805 * Called with the siglock held.
1807 static int sigkill_pending(struct task_struct *tsk)
1809 return sigismember(&tsk->pending.signal, SIGKILL) ||
1810 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
1814 * This must be called with current->sighand->siglock held.
1816 * This should be the path for all ptrace stops.
1817 * We always set current->last_siginfo while stopped here.
1818 * That makes it a way to test a stopped process for
1819 * being ptrace-stopped vs being job-control-stopped.
1821 * If we actually decide not to stop at all because the tracer
1822 * is gone, we keep current->exit_code unless clear_code.
1824 static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
1825 __releases(&current->sighand->siglock)
1826 __acquires(&current->sighand->siglock)
1828 bool gstop_done = false;
1830 if (arch_ptrace_stop_needed(exit_code, info)) {
1832 * The arch code has something special to do before a
1833 * ptrace stop. This is allowed to block, e.g. for faults
1834 * on user stack pages. We can't keep the siglock while
1835 * calling arch_ptrace_stop, so we must release it now.
1836 * To preserve proper semantics, we must do this before
1837 * any signal bookkeeping like checking group_stop_count.
1838 * Meanwhile, a SIGKILL could come in before we retake the
1839 * siglock. That must prevent us from sleeping in TASK_TRACED.
1840 * So after regaining the lock, we must check for SIGKILL.
1842 spin_unlock_irq(&current->sighand->siglock);
1843 arch_ptrace_stop(exit_code, info);
1844 spin_lock_irq(&current->sighand->siglock);
1845 if (sigkill_pending(current))
1846 return;
1850 * We're committing to trapping. TRACED should be visible before
1851 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1852 * Also, transition to TRACED and updates to ->jobctl should be
1853 * atomic with respect to siglock and should be done after the arch
1854 * hook as siglock is released and regrabbed across it.
1856 set_current_state(TASK_TRACED);
1858 current->last_siginfo = info;
1859 current->exit_code = exit_code;
1862 * If @why is CLD_STOPPED, we're trapping to participate in a group
1863 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1864 * across siglock relocks since INTERRUPT was scheduled, PENDING
1865 * could be clear now. We act as if SIGCONT is received after
1866 * TASK_TRACED is entered - ignore it.
1868 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
1869 gstop_done = task_participate_group_stop(current);
1871 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1872 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
1873 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
1874 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
1876 /* entering a trap, clear TRAPPING */
1877 task_clear_jobctl_trapping(current);
1879 spin_unlock_irq(&current->sighand->siglock);
1880 read_lock(&tasklist_lock);
1881 if (may_ptrace_stop()) {
1883 * Notify parents of the stop.
1885 * While ptraced, there are two parents - the ptracer and
1886 * the real_parent of the group_leader. The ptracer should
1887 * know about every stop while the real parent is only
1888 * interested in the completion of group stop. The states
1889 * for the two don't interact with each other. Notify
1890 * separately unless they're gonna be duplicates.
1892 do_notify_parent_cldstop(current, true, why);
1893 if (gstop_done && ptrace_reparented(current))
1894 do_notify_parent_cldstop(current, false, why);
1897 * Don't want to allow preemption here, because
1898 * sys_ptrace() needs this task to be inactive.
1900 * XXX: implement read_unlock_no_resched().
1902 preempt_disable();
1903 read_unlock(&tasklist_lock);
1904 preempt_enable_no_resched();
1905 freezable_schedule();
1906 } else {
1908 * By the time we got the lock, our tracer went away.
1909 * Don't drop the lock yet, another tracer may come.
1911 * If @gstop_done, the ptracer went away between group stop
1912 * completion and here. During detach, it would have set
1913 * JOBCTL_STOP_PENDING on us and we'll re-enter
1914 * TASK_STOPPED in do_signal_stop() on return, so notifying
1915 * the real parent of the group stop completion is enough.
1917 if (gstop_done)
1918 do_notify_parent_cldstop(current, false, why);
1920 /* tasklist protects us from ptrace_freeze_traced() */
1921 __set_current_state(TASK_RUNNING);
1922 if (clear_code)
1923 current->exit_code = 0;
1924 read_unlock(&tasklist_lock);
1928 * We are back. Now reacquire the siglock before touching
1929 * last_siginfo, so that we are sure to have synchronized with
1930 * any signal-sending on another CPU that wants to examine it.
1932 spin_lock_irq(&current->sighand->siglock);
1933 current->last_siginfo = NULL;
1935 /* LISTENING can be set only during STOP traps, clear it */
1936 current->jobctl &= ~JOBCTL_LISTENING;
1939 * Queued signals ignored us while we were stopped for tracing.
1940 * So check for any that we should take before resuming user mode.
1941 * This sets TIF_SIGPENDING, but never clears it.
1943 recalc_sigpending_tsk(current);
1946 static void ptrace_do_notify(int signr, int exit_code, int why)
1948 siginfo_t info;
1950 memset(&info, 0, sizeof info);
1951 info.si_signo = signr;
1952 info.si_code = exit_code;
1953 info.si_pid = task_pid_vnr(current);
1954 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1956 /* Let the debugger run. */
1957 ptrace_stop(exit_code, why, 1, &info);
1960 void ptrace_notify(int exit_code)
1962 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1963 if (unlikely(current->task_works))
1964 task_work_run();
1966 spin_lock_irq(&current->sighand->siglock);
1967 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
1968 spin_unlock_irq(&current->sighand->siglock);
1972 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1973 * @signr: signr causing group stop if initiating
1975 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1976 * and participate in it. If already set, participate in the existing
1977 * group stop. If participated in a group stop (and thus slept), %true is
1978 * returned with siglock released.
1980 * If ptraced, this function doesn't handle stop itself. Instead,
1981 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1982 * untouched. The caller must ensure that INTERRUPT trap handling takes
1983 * places afterwards.
1985 * CONTEXT:
1986 * Must be called with @current->sighand->siglock held, which is released
1987 * on %true return.
1989 * RETURNS:
1990 * %false if group stop is already cancelled or ptrace trap is scheduled.
1991 * %true if participated in group stop.
1993 static bool do_signal_stop(int signr)
1994 __releases(&current->sighand->siglock)
1996 struct signal_struct *sig = current->signal;
1998 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
1999 unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2000 struct task_struct *t;
2002 /* signr will be recorded in task->jobctl for retries */
2003 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2005 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2006 unlikely(signal_group_exit(sig)))
2007 return false;
2009 * There is no group stop already in progress. We must
2010 * initiate one now.
2012 * While ptraced, a task may be resumed while group stop is
2013 * still in effect and then receive a stop signal and
2014 * initiate another group stop. This deviates from the
2015 * usual behavior as two consecutive stop signals can't
2016 * cause two group stops when !ptraced. That is why we
2017 * also check !task_is_stopped(t) below.
2019 * The condition can be distinguished by testing whether
2020 * SIGNAL_STOP_STOPPED is already set. Don't generate
2021 * group_exit_code in such case.
2023 * This is not necessary for SIGNAL_STOP_CONTINUED because
2024 * an intervening stop signal is required to cause two
2025 * continued events regardless of ptrace.
2027 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2028 sig->group_exit_code = signr;
2030 sig->group_stop_count = 0;
2032 if (task_set_jobctl_pending(current, signr | gstop))
2033 sig->group_stop_count++;
2035 t = current;
2036 while_each_thread(current, t) {
2038 * Setting state to TASK_STOPPED for a group
2039 * stop is always done with the siglock held,
2040 * so this check has no races.
2042 if (!task_is_stopped(t) &&
2043 task_set_jobctl_pending(t, signr | gstop)) {
2044 sig->group_stop_count++;
2045 if (likely(!(t->ptrace & PT_SEIZED)))
2046 signal_wake_up(t, 0);
2047 else
2048 ptrace_trap_notify(t);
2053 if (likely(!current->ptrace)) {
2054 int notify = 0;
2057 * If there are no other threads in the group, or if there
2058 * is a group stop in progress and we are the last to stop,
2059 * report to the parent.
2061 if (task_participate_group_stop(current))
2062 notify = CLD_STOPPED;
2064 __set_current_state(TASK_STOPPED);
2065 spin_unlock_irq(&current->sighand->siglock);
2068 * Notify the parent of the group stop completion. Because
2069 * we're not holding either the siglock or tasklist_lock
2070 * here, ptracer may attach inbetween; however, this is for
2071 * group stop and should always be delivered to the real
2072 * parent of the group leader. The new ptracer will get
2073 * its notification when this task transitions into
2074 * TASK_TRACED.
2076 if (notify) {
2077 read_lock(&tasklist_lock);
2078 do_notify_parent_cldstop(current, false, notify);
2079 read_unlock(&tasklist_lock);
2082 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2083 freezable_schedule();
2084 return true;
2085 } else {
2087 * While ptraced, group stop is handled by STOP trap.
2088 * Schedule it and let the caller deal with it.
2090 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2091 return false;
2096 * do_jobctl_trap - take care of ptrace jobctl traps
2098 * When PT_SEIZED, it's used for both group stop and explicit
2099 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2100 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2101 * the stop signal; otherwise, %SIGTRAP.
2103 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2104 * number as exit_code and no siginfo.
2106 * CONTEXT:
2107 * Must be called with @current->sighand->siglock held, which may be
2108 * released and re-acquired before returning with intervening sleep.
2110 static void do_jobctl_trap(void)
2112 struct signal_struct *signal = current->signal;
2113 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2115 if (current->ptrace & PT_SEIZED) {
2116 if (!signal->group_stop_count &&
2117 !(signal->flags & SIGNAL_STOP_STOPPED))
2118 signr = SIGTRAP;
2119 WARN_ON_ONCE(!signr);
2120 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2121 CLD_STOPPED);
2122 } else {
2123 WARN_ON_ONCE(!signr);
2124 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2125 current->exit_code = 0;
2129 static int ptrace_signal(int signr, siginfo_t *info)
2131 ptrace_signal_deliver();
2133 * We do not check sig_kernel_stop(signr) but set this marker
2134 * unconditionally because we do not know whether debugger will
2135 * change signr. This flag has no meaning unless we are going
2136 * to stop after return from ptrace_stop(). In this case it will
2137 * be checked in do_signal_stop(), we should only stop if it was
2138 * not cleared by SIGCONT while we were sleeping. See also the
2139 * comment in dequeue_signal().
2141 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2142 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2144 /* We're back. Did the debugger cancel the sig? */
2145 signr = current->exit_code;
2146 if (signr == 0)
2147 return signr;
2149 current->exit_code = 0;
2152 * Update the siginfo structure if the signal has
2153 * changed. If the debugger wanted something
2154 * specific in the siginfo structure then it should
2155 * have updated *info via PTRACE_SETSIGINFO.
2157 if (signr != info->si_signo) {
2158 info->si_signo = signr;
2159 info->si_errno = 0;
2160 info->si_code = SI_USER;
2161 rcu_read_lock();
2162 info->si_pid = task_pid_vnr(current->parent);
2163 info->si_uid = from_kuid_munged(current_user_ns(),
2164 task_uid(current->parent));
2165 rcu_read_unlock();
2168 /* If the (new) signal is now blocked, requeue it. */
2169 if (sigismember(&current->blocked, signr)) {
2170 specific_send_sig_info(signr, info, current);
2171 signr = 0;
2174 return signr;
2177 int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
2178 struct pt_regs *regs, void *cookie)
2180 struct sighand_struct *sighand = current->sighand;
2181 struct signal_struct *signal = current->signal;
2182 int signr;
2184 if (unlikely(current->task_works))
2185 task_work_run();
2187 if (unlikely(uprobe_deny_signal()))
2188 return 0;
2191 * Do this once, we can't return to user-mode if freezing() == T.
2192 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2193 * thus do not need another check after return.
2195 try_to_freeze();
2197 relock:
2198 spin_lock_irq(&sighand->siglock);
2200 * Every stopped thread goes here after wakeup. Check to see if
2201 * we should notify the parent, prepare_signal(SIGCONT) encodes
2202 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2204 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2205 int why;
2207 if (signal->flags & SIGNAL_CLD_CONTINUED)
2208 why = CLD_CONTINUED;
2209 else
2210 why = CLD_STOPPED;
2212 signal->flags &= ~SIGNAL_CLD_MASK;
2214 spin_unlock_irq(&sighand->siglock);
2217 * Notify the parent that we're continuing. This event is
2218 * always per-process and doesn't make whole lot of sense
2219 * for ptracers, who shouldn't consume the state via
2220 * wait(2) either, but, for backward compatibility, notify
2221 * the ptracer of the group leader too unless it's gonna be
2222 * a duplicate.
2224 read_lock(&tasklist_lock);
2225 do_notify_parent_cldstop(current, false, why);
2227 if (ptrace_reparented(current->group_leader))
2228 do_notify_parent_cldstop(current->group_leader,
2229 true, why);
2230 read_unlock(&tasklist_lock);
2232 goto relock;
2235 for (;;) {
2236 struct k_sigaction *ka;
2238 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2239 do_signal_stop(0))
2240 goto relock;
2242 if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
2243 do_jobctl_trap();
2244 spin_unlock_irq(&sighand->siglock);
2245 goto relock;
2248 signr = dequeue_signal(current, &current->blocked, info);
2250 if (!signr)
2251 break; /* will return 0 */
2253 if (unlikely(current->ptrace) && signr != SIGKILL) {
2254 signr = ptrace_signal(signr, info);
2255 if (!signr)
2256 continue;
2259 ka = &sighand->action[signr-1];
2261 /* Trace actually delivered signals. */
2262 trace_signal_deliver(signr, info, ka);
2264 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2265 continue;
2266 if (ka->sa.sa_handler != SIG_DFL) {
2267 /* Run the handler. */
2268 *return_ka = *ka;
2270 if (ka->sa.sa_flags & SA_ONESHOT)
2271 ka->sa.sa_handler = SIG_DFL;
2273 break; /* will return non-zero "signr" value */
2277 * Now we are doing the default action for this signal.
2279 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2280 continue;
2283 * Global init gets no signals it doesn't want.
2284 * Container-init gets no signals it doesn't want from same
2285 * container.
2287 * Note that if global/container-init sees a sig_kernel_only()
2288 * signal here, the signal must have been generated internally
2289 * or must have come from an ancestor namespace. In either
2290 * case, the signal cannot be dropped.
2292 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2293 !sig_kernel_only(signr))
2294 continue;
2296 if (sig_kernel_stop(signr)) {
2298 * The default action is to stop all threads in
2299 * the thread group. The job control signals
2300 * do nothing in an orphaned pgrp, but SIGSTOP
2301 * always works. Note that siglock needs to be
2302 * dropped during the call to is_orphaned_pgrp()
2303 * because of lock ordering with tasklist_lock.
2304 * This allows an intervening SIGCONT to be posted.
2305 * We need to check for that and bail out if necessary.
2307 if (signr != SIGSTOP) {
2308 spin_unlock_irq(&sighand->siglock);
2310 /* signals can be posted during this window */
2312 if (is_current_pgrp_orphaned())
2313 goto relock;
2315 spin_lock_irq(&sighand->siglock);
2318 if (likely(do_signal_stop(info->si_signo))) {
2319 /* It released the siglock. */
2320 goto relock;
2324 * We didn't actually stop, due to a race
2325 * with SIGCONT or something like that.
2327 continue;
2330 spin_unlock_irq(&sighand->siglock);
2333 * Anything else is fatal, maybe with a core dump.
2335 current->flags |= PF_SIGNALED;
2337 if (sig_kernel_coredump(signr)) {
2338 if (print_fatal_signals)
2339 print_fatal_signal(info->si_signo);
2340 proc_coredump_connector(current);
2342 * If it was able to dump core, this kills all
2343 * other threads in the group and synchronizes with
2344 * their demise. If we lost the race with another
2345 * thread getting here, it set group_exit_code
2346 * first and our do_group_exit call below will use
2347 * that value and ignore the one we pass it.
2349 do_coredump(info);
2353 * Death signals, no core dump.
2355 do_group_exit(info->si_signo);
2356 /* NOTREACHED */
2358 spin_unlock_irq(&sighand->siglock);
2359 return signr;
2363 * signal_delivered -
2364 * @sig: number of signal being delivered
2365 * @info: siginfo_t of signal being delivered
2366 * @ka: sigaction setting that chose the handler
2367 * @regs: user register state
2368 * @stepping: nonzero if debugger single-step or block-step in use
2370 * This function should be called when a signal has successfully been
2371 * delivered. It updates the blocked signals accordingly (@ka->sa.sa_mask
2372 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2373 * is set in @ka->sa.sa_flags. Tracing is notified.
2375 void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka,
2376 struct pt_regs *regs, int stepping)
2378 sigset_t blocked;
2380 /* A signal was successfully delivered, and the
2381 saved sigmask was stored on the signal frame,
2382 and will be restored by sigreturn. So we can
2383 simply clear the restore sigmask flag. */
2384 clear_restore_sigmask();
2386 sigorsets(&blocked, &current->blocked, &ka->sa.sa_mask);
2387 if (!(ka->sa.sa_flags & SA_NODEFER))
2388 sigaddset(&blocked, sig);
2389 set_current_blocked(&blocked);
2390 tracehook_signal_handler(sig, info, ka, regs, stepping);
2393 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2395 if (failed)
2396 force_sigsegv(ksig->sig, current);
2397 else
2398 signal_delivered(ksig->sig, &ksig->info, &ksig->ka,
2399 signal_pt_regs(), stepping);
2403 * It could be that complete_signal() picked us to notify about the
2404 * group-wide signal. Other threads should be notified now to take
2405 * the shared signals in @which since we will not.
2407 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2409 sigset_t retarget;
2410 struct task_struct *t;
2412 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2413 if (sigisemptyset(&retarget))
2414 return;
2416 t = tsk;
2417 while_each_thread(tsk, t) {
2418 if (t->flags & PF_EXITING)
2419 continue;
2421 if (!has_pending_signals(&retarget, &t->blocked))
2422 continue;
2423 /* Remove the signals this thread can handle. */
2424 sigandsets(&retarget, &retarget, &t->blocked);
2426 if (!signal_pending(t))
2427 signal_wake_up(t, 0);
2429 if (sigisemptyset(&retarget))
2430 break;
2434 void exit_signals(struct task_struct *tsk)
2436 int group_stop = 0;
2437 sigset_t unblocked;
2440 * @tsk is about to have PF_EXITING set - lock out users which
2441 * expect stable threadgroup.
2443 threadgroup_change_begin(tsk);
2445 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2446 tsk->flags |= PF_EXITING;
2447 threadgroup_change_end(tsk);
2448 return;
2451 spin_lock_irq(&tsk->sighand->siglock);
2453 * From now this task is not visible for group-wide signals,
2454 * see wants_signal(), do_signal_stop().
2456 tsk->flags |= PF_EXITING;
2458 threadgroup_change_end(tsk);
2460 if (!signal_pending(tsk))
2461 goto out;
2463 unblocked = tsk->blocked;
2464 signotset(&unblocked);
2465 retarget_shared_pending(tsk, &unblocked);
2467 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2468 task_participate_group_stop(tsk))
2469 group_stop = CLD_STOPPED;
2470 out:
2471 spin_unlock_irq(&tsk->sighand->siglock);
2474 * If group stop has completed, deliver the notification. This
2475 * should always go to the real parent of the group leader.
2477 if (unlikely(group_stop)) {
2478 read_lock(&tasklist_lock);
2479 do_notify_parent_cldstop(tsk, false, group_stop);
2480 read_unlock(&tasklist_lock);
2484 EXPORT_SYMBOL(recalc_sigpending);
2485 EXPORT_SYMBOL_GPL(dequeue_signal);
2486 EXPORT_SYMBOL(flush_signals);
2487 EXPORT_SYMBOL(force_sig);
2488 EXPORT_SYMBOL(send_sig);
2489 EXPORT_SYMBOL(send_sig_info);
2490 EXPORT_SYMBOL(sigprocmask);
2491 EXPORT_SYMBOL(block_all_signals);
2492 EXPORT_SYMBOL(unblock_all_signals);
2496 * System call entry points.
2500 * sys_restart_syscall - restart a system call
2502 SYSCALL_DEFINE0(restart_syscall)
2504 struct restart_block *restart = &current_thread_info()->restart_block;
2505 return restart->fn(restart);
2508 long do_no_restart_syscall(struct restart_block *param)
2510 return -EINTR;
2513 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2515 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2516 sigset_t newblocked;
2517 /* A set of now blocked but previously unblocked signals. */
2518 sigandnsets(&newblocked, newset, &current->blocked);
2519 retarget_shared_pending(tsk, &newblocked);
2521 tsk->blocked = *newset;
2522 recalc_sigpending();
2526 * set_current_blocked - change current->blocked mask
2527 * @newset: new mask
2529 * It is wrong to change ->blocked directly, this helper should be used
2530 * to ensure the process can't miss a shared signal we are going to block.
2532 void set_current_blocked(sigset_t *newset)
2534 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2535 __set_current_blocked(newset);
2538 void __set_current_blocked(const sigset_t *newset)
2540 struct task_struct *tsk = current;
2542 spin_lock_irq(&tsk->sighand->siglock);
2543 __set_task_blocked(tsk, newset);
2544 spin_unlock_irq(&tsk->sighand->siglock);
2548 * This is also useful for kernel threads that want to temporarily
2549 * (or permanently) block certain signals.
2551 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2552 * interface happily blocks "unblockable" signals like SIGKILL
2553 * and friends.
2555 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2557 struct task_struct *tsk = current;
2558 sigset_t newset;
2560 /* Lockless, only current can change ->blocked, never from irq */
2561 if (oldset)
2562 *oldset = tsk->blocked;
2564 switch (how) {
2565 case SIG_BLOCK:
2566 sigorsets(&newset, &tsk->blocked, set);
2567 break;
2568 case SIG_UNBLOCK:
2569 sigandnsets(&newset, &tsk->blocked, set);
2570 break;
2571 case SIG_SETMASK:
2572 newset = *set;
2573 break;
2574 default:
2575 return -EINVAL;
2578 __set_current_blocked(&newset);
2579 return 0;
2583 * sys_rt_sigprocmask - change the list of currently blocked signals
2584 * @how: whether to add, remove, or set signals
2585 * @nset: stores pending signals
2586 * @oset: previous value of signal mask if non-null
2587 * @sigsetsize: size of sigset_t type
2589 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2590 sigset_t __user *, oset, size_t, sigsetsize)
2592 sigset_t old_set, new_set;
2593 int error;
2595 /* XXX: Don't preclude handling different sized sigset_t's. */
2596 if (sigsetsize != sizeof(sigset_t))
2597 return -EINVAL;
2599 old_set = current->blocked;
2601 if (nset) {
2602 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2603 return -EFAULT;
2604 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2606 error = sigprocmask(how, &new_set, NULL);
2607 if (error)
2608 return error;
2611 if (oset) {
2612 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2613 return -EFAULT;
2616 return 0;
2619 #ifdef CONFIG_COMPAT
2620 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2621 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2623 #ifdef __BIG_ENDIAN
2624 sigset_t old_set = current->blocked;
2626 /* XXX: Don't preclude handling different sized sigset_t's. */
2627 if (sigsetsize != sizeof(sigset_t))
2628 return -EINVAL;
2630 if (nset) {
2631 compat_sigset_t new32;
2632 sigset_t new_set;
2633 int error;
2634 if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
2635 return -EFAULT;
2637 sigset_from_compat(&new_set, &new32);
2638 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2640 error = sigprocmask(how, &new_set, NULL);
2641 if (error)
2642 return error;
2644 if (oset) {
2645 compat_sigset_t old32;
2646 sigset_to_compat(&old32, &old_set);
2647 if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
2648 return -EFAULT;
2650 return 0;
2651 #else
2652 return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
2653 (sigset_t __user *)oset, sigsetsize);
2654 #endif
2656 #endif
2658 static int do_sigpending(void *set, unsigned long sigsetsize)
2660 if (sigsetsize > sizeof(sigset_t))
2661 return -EINVAL;
2663 spin_lock_irq(&current->sighand->siglock);
2664 sigorsets(set, &current->pending.signal,
2665 &current->signal->shared_pending.signal);
2666 spin_unlock_irq(&current->sighand->siglock);
2668 /* Outside the lock because only this thread touches it. */
2669 sigandsets(set, &current->blocked, set);
2670 return 0;
2674 * sys_rt_sigpending - examine a pending signal that has been raised
2675 * while blocked
2676 * @uset: stores pending signals
2677 * @sigsetsize: size of sigset_t type or larger
2679 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
2681 sigset_t set;
2682 int err = do_sigpending(&set, sigsetsize);
2683 if (!err && copy_to_user(uset, &set, sigsetsize))
2684 err = -EFAULT;
2685 return err;
2688 #ifdef CONFIG_COMPAT
2689 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
2690 compat_size_t, sigsetsize)
2692 #ifdef __BIG_ENDIAN
2693 sigset_t set;
2694 int err = do_sigpending(&set, sigsetsize);
2695 if (!err) {
2696 compat_sigset_t set32;
2697 sigset_to_compat(&set32, &set);
2698 /* we can get here only if sigsetsize <= sizeof(set) */
2699 if (copy_to_user(uset, &set32, sigsetsize))
2700 err = -EFAULT;
2702 return err;
2703 #else
2704 return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
2705 #endif
2707 #endif
2709 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2711 int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
2713 int err;
2715 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2716 return -EFAULT;
2717 if (from->si_code < 0)
2718 return __copy_to_user(to, from, sizeof(siginfo_t))
2719 ? -EFAULT : 0;
2721 * If you change siginfo_t structure, please be sure
2722 * this code is fixed accordingly.
2723 * Please remember to update the signalfd_copyinfo() function
2724 * inside fs/signalfd.c too, in case siginfo_t changes.
2725 * It should never copy any pad contained in the structure
2726 * to avoid security leaks, but must copy the generic
2727 * 3 ints plus the relevant union member.
2729 err = __put_user(from->si_signo, &to->si_signo);
2730 err |= __put_user(from->si_errno, &to->si_errno);
2731 err |= __put_user((short)from->si_code, &to->si_code);
2732 switch (from->si_code & __SI_MASK) {
2733 case __SI_KILL:
2734 err |= __put_user(from->si_pid, &to->si_pid);
2735 err |= __put_user(from->si_uid, &to->si_uid);
2736 break;
2737 case __SI_TIMER:
2738 err |= __put_user(from->si_tid, &to->si_tid);
2739 err |= __put_user(from->si_overrun, &to->si_overrun);
2740 err |= __put_user(from->si_ptr, &to->si_ptr);
2741 break;
2742 case __SI_POLL:
2743 err |= __put_user(from->si_band, &to->si_band);
2744 err |= __put_user(from->si_fd, &to->si_fd);
2745 break;
2746 case __SI_FAULT:
2747 err |= __put_user(from->si_addr, &to->si_addr);
2748 #ifdef __ARCH_SI_TRAPNO
2749 err |= __put_user(from->si_trapno, &to->si_trapno);
2750 #endif
2751 #ifdef BUS_MCEERR_AO
2753 * Other callers might not initialize the si_lsb field,
2754 * so check explicitly for the right codes here.
2756 if (from->si_signo == SIGBUS &&
2757 (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
2758 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2759 #endif
2760 break;
2761 case __SI_CHLD:
2762 err |= __put_user(from->si_pid, &to->si_pid);
2763 err |= __put_user(from->si_uid, &to->si_uid);
2764 err |= __put_user(from->si_status, &to->si_status);
2765 err |= __put_user(from->si_utime, &to->si_utime);
2766 err |= __put_user(from->si_stime, &to->si_stime);
2767 break;
2768 case __SI_RT: /* This is not generated by the kernel as of now. */
2769 case __SI_MESGQ: /* But this is */
2770 err |= __put_user(from->si_pid, &to->si_pid);
2771 err |= __put_user(from->si_uid, &to->si_uid);
2772 err |= __put_user(from->si_ptr, &to->si_ptr);
2773 break;
2774 #ifdef __ARCH_SIGSYS
2775 case __SI_SYS:
2776 err |= __put_user(from->si_call_addr, &to->si_call_addr);
2777 err |= __put_user(from->si_syscall, &to->si_syscall);
2778 err |= __put_user(from->si_arch, &to->si_arch);
2779 break;
2780 #endif
2781 default: /* this is just in case for now ... */
2782 err |= __put_user(from->si_pid, &to->si_pid);
2783 err |= __put_user(from->si_uid, &to->si_uid);
2784 break;
2786 return err;
2789 #endif
2792 * do_sigtimedwait - wait for queued signals specified in @which
2793 * @which: queued signals to wait for
2794 * @info: if non-null, the signal's siginfo is returned here
2795 * @ts: upper bound on process time suspension
2797 int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
2798 const struct timespec *ts)
2800 struct task_struct *tsk = current;
2801 long timeout = MAX_SCHEDULE_TIMEOUT;
2802 sigset_t mask = *which;
2803 int sig;
2805 if (ts) {
2806 if (!timespec_valid(ts))
2807 return -EINVAL;
2808 timeout = timespec_to_jiffies(ts);
2810 * We can be close to the next tick, add another one
2811 * to ensure we will wait at least the time asked for.
2813 if (ts->tv_sec || ts->tv_nsec)
2814 timeout++;
2818 * Invert the set of allowed signals to get those we want to block.
2820 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
2821 signotset(&mask);
2823 spin_lock_irq(&tsk->sighand->siglock);
2824 sig = dequeue_signal(tsk, &mask, info);
2825 if (!sig && timeout) {
2827 * None ready, temporarily unblock those we're interested
2828 * while we are sleeping in so that we'll be awakened when
2829 * they arrive. Unblocking is always fine, we can avoid
2830 * set_current_blocked().
2832 tsk->real_blocked = tsk->blocked;
2833 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
2834 recalc_sigpending();
2835 spin_unlock_irq(&tsk->sighand->siglock);
2837 timeout = freezable_schedule_timeout_interruptible(timeout);
2839 spin_lock_irq(&tsk->sighand->siglock);
2840 __set_task_blocked(tsk, &tsk->real_blocked);
2841 sigemptyset(&tsk->real_blocked);
2842 sig = dequeue_signal(tsk, &mask, info);
2844 spin_unlock_irq(&tsk->sighand->siglock);
2846 if (sig)
2847 return sig;
2848 return timeout ? -EINTR : -EAGAIN;
2852 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2853 * in @uthese
2854 * @uthese: queued signals to wait for
2855 * @uinfo: if non-null, the signal's siginfo is returned here
2856 * @uts: upper bound on process time suspension
2857 * @sigsetsize: size of sigset_t type
2859 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2860 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2861 size_t, sigsetsize)
2863 sigset_t these;
2864 struct timespec ts;
2865 siginfo_t info;
2866 int ret;
2868 /* XXX: Don't preclude handling different sized sigset_t's. */
2869 if (sigsetsize != sizeof(sigset_t))
2870 return -EINVAL;
2872 if (copy_from_user(&these, uthese, sizeof(these)))
2873 return -EFAULT;
2875 if (uts) {
2876 if (copy_from_user(&ts, uts, sizeof(ts)))
2877 return -EFAULT;
2880 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
2882 if (ret > 0 && uinfo) {
2883 if (copy_siginfo_to_user(uinfo, &info))
2884 ret = -EFAULT;
2887 return ret;
2891 * sys_kill - send a signal to a process
2892 * @pid: the PID of the process
2893 * @sig: signal to be sent
2895 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2897 struct siginfo info;
2899 info.si_signo = sig;
2900 info.si_errno = 0;
2901 info.si_code = SI_USER;
2902 info.si_pid = task_tgid_vnr(current);
2903 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2905 return kill_something_info(sig, &info, pid);
2908 static int
2909 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2911 struct task_struct *p;
2912 int error = -ESRCH;
2914 rcu_read_lock();
2915 p = find_task_by_vpid(pid);
2916 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2917 error = check_kill_permission(sig, info, p);
2919 * The null signal is a permissions and process existence
2920 * probe. No signal is actually delivered.
2922 if (!error && sig) {
2923 error = do_send_sig_info(sig, info, p, false);
2925 * If lock_task_sighand() failed we pretend the task
2926 * dies after receiving the signal. The window is tiny,
2927 * and the signal is private anyway.
2929 if (unlikely(error == -ESRCH))
2930 error = 0;
2933 rcu_read_unlock();
2935 return error;
2938 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2940 struct siginfo info = {};
2942 info.si_signo = sig;
2943 info.si_errno = 0;
2944 info.si_code = SI_TKILL;
2945 info.si_pid = task_tgid_vnr(current);
2946 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2948 return do_send_specific(tgid, pid, sig, &info);
2952 * sys_tgkill - send signal to one specific thread
2953 * @tgid: the thread group ID of the thread
2954 * @pid: the PID of the thread
2955 * @sig: signal to be sent
2957 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2958 * exists but it's not belonging to the target process anymore. This
2959 * method solves the problem of threads exiting and PIDs getting reused.
2961 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2963 /* This is only valid for single tasks */
2964 if (pid <= 0 || tgid <= 0)
2965 return -EINVAL;
2967 return do_tkill(tgid, pid, sig);
2971 * sys_tkill - send signal to one specific task
2972 * @pid: the PID of the task
2973 * @sig: signal to be sent
2975 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2977 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
2979 /* This is only valid for single tasks */
2980 if (pid <= 0)
2981 return -EINVAL;
2983 return do_tkill(0, pid, sig);
2986 static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
2988 /* Not even root can pretend to send signals from the kernel.
2989 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2991 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
2992 (task_pid_vnr(current) != pid)) {
2993 /* We used to allow any < 0 si_code */
2994 WARN_ON_ONCE(info->si_code < 0);
2995 return -EPERM;
2997 info->si_signo = sig;
2999 /* POSIX.1b doesn't mention process groups. */
3000 return kill_proc_info(sig, info, pid);
3004 * sys_rt_sigqueueinfo - send signal information to a signal
3005 * @pid: the PID of the thread
3006 * @sig: signal to be sent
3007 * @uinfo: signal info to be sent
3009 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3010 siginfo_t __user *, uinfo)
3012 siginfo_t info;
3013 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3014 return -EFAULT;
3015 return do_rt_sigqueueinfo(pid, sig, &info);
3018 #ifdef CONFIG_COMPAT
3019 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3020 compat_pid_t, pid,
3021 int, sig,
3022 struct compat_siginfo __user *, uinfo)
3024 siginfo_t info = {};
3025 int ret = copy_siginfo_from_user32(&info, uinfo);
3026 if (unlikely(ret))
3027 return ret;
3028 return do_rt_sigqueueinfo(pid, sig, &info);
3030 #endif
3032 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
3034 /* This is only valid for single tasks */
3035 if (pid <= 0 || tgid <= 0)
3036 return -EINVAL;
3038 /* Not even root can pretend to send signals from the kernel.
3039 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3041 if (((info->si_code >= 0 || info->si_code == SI_TKILL)) &&
3042 (task_pid_vnr(current) != pid)) {
3043 /* We used to allow any < 0 si_code */
3044 WARN_ON_ONCE(info->si_code < 0);
3045 return -EPERM;
3047 info->si_signo = sig;
3049 return do_send_specific(tgid, pid, sig, info);
3052 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3053 siginfo_t __user *, uinfo)
3055 siginfo_t info;
3057 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
3058 return -EFAULT;
3060 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3063 #ifdef CONFIG_COMPAT
3064 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3065 compat_pid_t, tgid,
3066 compat_pid_t, pid,
3067 int, sig,
3068 struct compat_siginfo __user *, uinfo)
3070 siginfo_t info = {};
3072 if (copy_siginfo_from_user32(&info, uinfo))
3073 return -EFAULT;
3074 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3076 #endif
3079 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3081 void kernel_sigaction(int sig, __sighandler_t action)
3083 spin_lock_irq(&current->sighand->siglock);
3084 current->sighand->action[sig - 1].sa.sa_handler = action;
3085 if (action == SIG_IGN) {
3086 sigset_t mask;
3088 sigemptyset(&mask);
3089 sigaddset(&mask, sig);
3091 flush_sigqueue_mask(&mask, &current->signal->shared_pending);
3092 flush_sigqueue_mask(&mask, &current->pending);
3093 recalc_sigpending();
3095 spin_unlock_irq(&current->sighand->siglock);
3097 EXPORT_SYMBOL(kernel_sigaction);
3099 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3101 struct task_struct *p = current, *t;
3102 struct k_sigaction *k;
3103 sigset_t mask;
3105 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3106 return -EINVAL;
3108 k = &p->sighand->action[sig-1];
3110 spin_lock_irq(&p->sighand->siglock);
3111 if (oact)
3112 *oact = *k;
3114 if (act) {
3115 sigdelsetmask(&act->sa.sa_mask,
3116 sigmask(SIGKILL) | sigmask(SIGSTOP));
3117 *k = *act;
3119 * POSIX 3.3.1.3:
3120 * "Setting a signal action to SIG_IGN for a signal that is
3121 * pending shall cause the pending signal to be discarded,
3122 * whether or not it is blocked."
3124 * "Setting a signal action to SIG_DFL for a signal that is
3125 * pending and whose default action is to ignore the signal
3126 * (for example, SIGCHLD), shall cause the pending signal to
3127 * be discarded, whether or not it is blocked"
3129 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3130 sigemptyset(&mask);
3131 sigaddset(&mask, sig);
3132 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3133 for_each_thread(p, t)
3134 flush_sigqueue_mask(&mask, &t->pending);
3138 spin_unlock_irq(&p->sighand->siglock);
3139 return 0;
3142 static int
3143 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
3145 stack_t oss;
3146 int error;
3148 oss.ss_sp = (void __user *) current->sas_ss_sp;
3149 oss.ss_size = current->sas_ss_size;
3150 oss.ss_flags = sas_ss_flags(sp);
3152 if (uss) {
3153 void __user *ss_sp;
3154 size_t ss_size;
3155 int ss_flags;
3157 error = -EFAULT;
3158 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
3159 goto out;
3160 error = __get_user(ss_sp, &uss->ss_sp) |
3161 __get_user(ss_flags, &uss->ss_flags) |
3162 __get_user(ss_size, &uss->ss_size);
3163 if (error)
3164 goto out;
3166 error = -EPERM;
3167 if (on_sig_stack(sp))
3168 goto out;
3170 error = -EINVAL;
3172 * Note - this code used to test ss_flags incorrectly:
3173 * old code may have been written using ss_flags==0
3174 * to mean ss_flags==SS_ONSTACK (as this was the only
3175 * way that worked) - this fix preserves that older
3176 * mechanism.
3178 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
3179 goto out;
3181 if (ss_flags == SS_DISABLE) {
3182 ss_size = 0;
3183 ss_sp = NULL;
3184 } else {
3185 error = -ENOMEM;
3186 if (ss_size < MINSIGSTKSZ)
3187 goto out;
3190 current->sas_ss_sp = (unsigned long) ss_sp;
3191 current->sas_ss_size = ss_size;
3194 error = 0;
3195 if (uoss) {
3196 error = -EFAULT;
3197 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
3198 goto out;
3199 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
3200 __put_user(oss.ss_size, &uoss->ss_size) |
3201 __put_user(oss.ss_flags, &uoss->ss_flags);
3204 out:
3205 return error;
3207 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3209 return do_sigaltstack(uss, uoss, current_user_stack_pointer());
3212 int restore_altstack(const stack_t __user *uss)
3214 int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
3215 /* squash all but EFAULT for now */
3216 return err == -EFAULT ? err : 0;
3219 int __save_altstack(stack_t __user *uss, unsigned long sp)
3221 struct task_struct *t = current;
3222 return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3223 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3224 __put_user(t->sas_ss_size, &uss->ss_size);
3227 #ifdef CONFIG_COMPAT
3228 COMPAT_SYSCALL_DEFINE2(sigaltstack,
3229 const compat_stack_t __user *, uss_ptr,
3230 compat_stack_t __user *, uoss_ptr)
3232 stack_t uss, uoss;
3233 int ret;
3234 mm_segment_t seg;
3236 if (uss_ptr) {
3237 compat_stack_t uss32;
3239 memset(&uss, 0, sizeof(stack_t));
3240 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
3241 return -EFAULT;
3242 uss.ss_sp = compat_ptr(uss32.ss_sp);
3243 uss.ss_flags = uss32.ss_flags;
3244 uss.ss_size = uss32.ss_size;
3246 seg = get_fs();
3247 set_fs(KERNEL_DS);
3248 ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
3249 (stack_t __force __user *) &uoss,
3250 compat_user_stack_pointer());
3251 set_fs(seg);
3252 if (ret >= 0 && uoss_ptr) {
3253 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
3254 __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
3255 __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
3256 __put_user(uoss.ss_size, &uoss_ptr->ss_size))
3257 ret = -EFAULT;
3259 return ret;
3262 int compat_restore_altstack(const compat_stack_t __user *uss)
3264 int err = compat_sys_sigaltstack(uss, NULL);
3265 /* squash all but -EFAULT for now */
3266 return err == -EFAULT ? err : 0;
3269 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
3271 struct task_struct *t = current;
3272 return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
3273 __put_user(sas_ss_flags(sp), &uss->ss_flags) |
3274 __put_user(t->sas_ss_size, &uss->ss_size);
3276 #endif
3278 #ifdef __ARCH_WANT_SYS_SIGPENDING
3281 * sys_sigpending - examine pending signals
3282 * @set: where mask of pending signal is returned
3284 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
3286 return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
3289 #endif
3291 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3293 * sys_sigprocmask - examine and change blocked signals
3294 * @how: whether to add, remove, or set signals
3295 * @nset: signals to add or remove (if non-null)
3296 * @oset: previous value of signal mask if non-null
3298 * Some platforms have their own version with special arguments;
3299 * others support only sys_rt_sigprocmask.
3302 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
3303 old_sigset_t __user *, oset)
3305 old_sigset_t old_set, new_set;
3306 sigset_t new_blocked;
3308 old_set = current->blocked.sig[0];
3310 if (nset) {
3311 if (copy_from_user(&new_set, nset, sizeof(*nset)))
3312 return -EFAULT;
3314 new_blocked = current->blocked;
3316 switch (how) {
3317 case SIG_BLOCK:
3318 sigaddsetmask(&new_blocked, new_set);
3319 break;
3320 case SIG_UNBLOCK:
3321 sigdelsetmask(&new_blocked, new_set);
3322 break;
3323 case SIG_SETMASK:
3324 new_blocked.sig[0] = new_set;
3325 break;
3326 default:
3327 return -EINVAL;
3330 set_current_blocked(&new_blocked);
3333 if (oset) {
3334 if (copy_to_user(oset, &old_set, sizeof(*oset)))
3335 return -EFAULT;
3338 return 0;
3340 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3342 #ifndef CONFIG_ODD_RT_SIGACTION
3344 * sys_rt_sigaction - alter an action taken by a process
3345 * @sig: signal to be sent
3346 * @act: new sigaction
3347 * @oact: used to save the previous sigaction
3348 * @sigsetsize: size of sigset_t type
3350 SYSCALL_DEFINE4(rt_sigaction, int, sig,
3351 const struct sigaction __user *, act,
3352 struct sigaction __user *, oact,
3353 size_t, sigsetsize)
3355 struct k_sigaction new_sa, old_sa;
3356 int ret = -EINVAL;
3358 /* XXX: Don't preclude handling different sized sigset_t's. */
3359 if (sigsetsize != sizeof(sigset_t))
3360 goto out;
3362 if (act) {
3363 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
3364 return -EFAULT;
3367 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
3369 if (!ret && oact) {
3370 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
3371 return -EFAULT;
3373 out:
3374 return ret;
3376 #ifdef CONFIG_COMPAT
3377 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
3378 const struct compat_sigaction __user *, act,
3379 struct compat_sigaction __user *, oact,
3380 compat_size_t, sigsetsize)
3382 struct k_sigaction new_ka, old_ka;
3383 compat_sigset_t mask;
3384 #ifdef __ARCH_HAS_SA_RESTORER
3385 compat_uptr_t restorer;
3386 #endif
3387 int ret;
3389 /* XXX: Don't preclude handling different sized sigset_t's. */
3390 if (sigsetsize != sizeof(compat_sigset_t))
3391 return -EINVAL;
3393 if (act) {
3394 compat_uptr_t handler;
3395 ret = get_user(handler, &act->sa_handler);
3396 new_ka.sa.sa_handler = compat_ptr(handler);
3397 #ifdef __ARCH_HAS_SA_RESTORER
3398 ret |= get_user(restorer, &act->sa_restorer);
3399 new_ka.sa.sa_restorer = compat_ptr(restorer);
3400 #endif
3401 ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
3402 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
3403 if (ret)
3404 return -EFAULT;
3405 sigset_from_compat(&new_ka.sa.sa_mask, &mask);
3408 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3409 if (!ret && oact) {
3410 sigset_to_compat(&mask, &old_ka.sa.sa_mask);
3411 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
3412 &oact->sa_handler);
3413 ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
3414 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
3415 #ifdef __ARCH_HAS_SA_RESTORER
3416 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3417 &oact->sa_restorer);
3418 #endif
3420 return ret;
3422 #endif
3423 #endif /* !CONFIG_ODD_RT_SIGACTION */
3425 #ifdef CONFIG_OLD_SIGACTION
3426 SYSCALL_DEFINE3(sigaction, int, sig,
3427 const struct old_sigaction __user *, act,
3428 struct old_sigaction __user *, oact)
3430 struct k_sigaction new_ka, old_ka;
3431 int ret;
3433 if (act) {
3434 old_sigset_t mask;
3435 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3436 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
3437 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
3438 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3439 __get_user(mask, &act->sa_mask))
3440 return -EFAULT;
3441 #ifdef __ARCH_HAS_KA_RESTORER
3442 new_ka.ka_restorer = NULL;
3443 #endif
3444 siginitset(&new_ka.sa.sa_mask, mask);
3447 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3449 if (!ret && oact) {
3450 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3451 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
3452 __put_user(old_ka.sa.sa_restorer, &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))
3455 return -EFAULT;
3458 return ret;
3460 #endif
3461 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3462 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
3463 const struct compat_old_sigaction __user *, act,
3464 struct compat_old_sigaction __user *, oact)
3466 struct k_sigaction new_ka, old_ka;
3467 int ret;
3468 compat_old_sigset_t mask;
3469 compat_uptr_t handler, restorer;
3471 if (act) {
3472 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
3473 __get_user(handler, &act->sa_handler) ||
3474 __get_user(restorer, &act->sa_restorer) ||
3475 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
3476 __get_user(mask, &act->sa_mask))
3477 return -EFAULT;
3479 #ifdef __ARCH_HAS_KA_RESTORER
3480 new_ka.ka_restorer = NULL;
3481 #endif
3482 new_ka.sa.sa_handler = compat_ptr(handler);
3483 new_ka.sa.sa_restorer = compat_ptr(restorer);
3484 siginitset(&new_ka.sa.sa_mask, mask);
3487 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
3489 if (!ret && oact) {
3490 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
3491 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
3492 &oact->sa_handler) ||
3493 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
3494 &oact->sa_restorer) ||
3495 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
3496 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
3497 return -EFAULT;
3499 return ret;
3501 #endif
3503 #ifdef CONFIG_SGETMASK_SYSCALL
3506 * For backwards compatibility. Functionality superseded by sigprocmask.
3508 SYSCALL_DEFINE0(sgetmask)
3510 /* SMP safe */
3511 return current->blocked.sig[0];
3514 SYSCALL_DEFINE1(ssetmask, int, newmask)
3516 int old = current->blocked.sig[0];
3517 sigset_t newset;
3519 siginitset(&newset, newmask);
3520 set_current_blocked(&newset);
3522 return old;
3524 #endif /* CONFIG_SGETMASK_SYSCALL */
3526 #ifdef __ARCH_WANT_SYS_SIGNAL
3528 * For backwards compatibility. Functionality superseded by sigaction.
3530 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
3532 struct k_sigaction new_sa, old_sa;
3533 int ret;
3535 new_sa.sa.sa_handler = handler;
3536 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
3537 sigemptyset(&new_sa.sa.sa_mask);
3539 ret = do_sigaction(sig, &new_sa, &old_sa);
3541 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
3543 #endif /* __ARCH_WANT_SYS_SIGNAL */
3545 #ifdef __ARCH_WANT_SYS_PAUSE
3547 SYSCALL_DEFINE0(pause)
3549 while (!signal_pending(current)) {
3550 current->state = TASK_INTERRUPTIBLE;
3551 schedule();
3553 return -ERESTARTNOHAND;
3556 #endif
3558 static int sigsuspend(sigset_t *set)
3560 current->saved_sigmask = current->blocked;
3561 set_current_blocked(set);
3563 current->state = TASK_INTERRUPTIBLE;
3564 schedule();
3565 set_restore_sigmask();
3566 return -ERESTARTNOHAND;
3570 * sys_rt_sigsuspend - replace the signal mask for a value with the
3571 * @unewset value until a signal is received
3572 * @unewset: new signal mask value
3573 * @sigsetsize: size of sigset_t type
3575 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
3577 sigset_t newset;
3579 /* XXX: Don't preclude handling different sized sigset_t's. */
3580 if (sigsetsize != sizeof(sigset_t))
3581 return -EINVAL;
3583 if (copy_from_user(&newset, unewset, sizeof(newset)))
3584 return -EFAULT;
3585 return sigsuspend(&newset);
3588 #ifdef CONFIG_COMPAT
3589 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
3591 #ifdef __BIG_ENDIAN
3592 sigset_t newset;
3593 compat_sigset_t newset32;
3595 /* XXX: Don't preclude handling different sized sigset_t's. */
3596 if (sigsetsize != sizeof(sigset_t))
3597 return -EINVAL;
3599 if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
3600 return -EFAULT;
3601 sigset_from_compat(&newset, &newset32);
3602 return sigsuspend(&newset);
3603 #else
3604 /* on little-endian bitmaps don't care about granularity */
3605 return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize);
3606 #endif
3608 #endif
3610 #ifdef CONFIG_OLD_SIGSUSPEND
3611 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
3613 sigset_t blocked;
3614 siginitset(&blocked, mask);
3615 return sigsuspend(&blocked);
3617 #endif
3618 #ifdef CONFIG_OLD_SIGSUSPEND3
3619 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
3621 sigset_t blocked;
3622 siginitset(&blocked, mask);
3623 return sigsuspend(&blocked);
3625 #endif
3627 __weak const char *arch_vma_name(struct vm_area_struct *vma)
3629 return NULL;
3632 void __init signals_init(void)
3634 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
3637 #ifdef CONFIG_KGDB_KDB
3638 #include <linux/kdb.h>
3640 * kdb_send_sig_info - Allows kdb to send signals without exposing
3641 * signal internals. This function checks if the required locks are
3642 * available before calling the main signal code, to avoid kdb
3643 * deadlocks.
3645 void
3646 kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
3648 static struct task_struct *kdb_prev_t;
3649 int sig, new_t;
3650 if (!spin_trylock(&t->sighand->siglock)) {
3651 kdb_printf("Can't do kill command now.\n"
3652 "The sigmask lock is held somewhere else in "
3653 "kernel, try again later\n");
3654 return;
3656 spin_unlock(&t->sighand->siglock);
3657 new_t = kdb_prev_t != t;
3658 kdb_prev_t = t;
3659 if (t->state != TASK_RUNNING && new_t) {
3660 kdb_printf("Process is not RUNNING, sending a signal from "
3661 "kdb risks deadlock\n"
3662 "on the run queue locks. "
3663 "The signal has _not_ been sent.\n"
3664 "Reissue the kill command if you want to risk "
3665 "the deadlock.\n");
3666 return;
3668 sig = info->si_signo;
3669 if (send_sig_info(sig, info, t))
3670 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3671 sig, t->pid);
3672 else
3673 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
3675 #endif /* CONFIG_KGDB_KDB */