2 * linux/kernel/signal.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
8 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
9 * Changes to use preallocated sigqueue structures
10 * to allow signals to be sent reliably.
13 #include <linux/slab.h>
14 #include <linux/export.h>
15 #include <linux/init.h>
16 #include <linux/sched/mm.h>
17 #include <linux/sched/user.h>
18 #include <linux/sched/debug.h>
19 #include <linux/sched/task.h>
20 #include <linux/sched/task_stack.h>
21 #include <linux/sched/cputime.h>
23 #include <linux/tty.h>
24 #include <linux/binfmts.h>
25 #include <linux/coredump.h>
26 #include <linux/security.h>
27 #include <linux/syscalls.h>
28 #include <linux/ptrace.h>
29 #include <linux/signal.h>
30 #include <linux/signalfd.h>
31 #include <linux/ratelimit.h>
32 #include <linux/tracehook.h>
33 #include <linux/capability.h>
34 #include <linux/freezer.h>
35 #include <linux/pid_namespace.h>
36 #include <linux/nsproxy.h>
37 #include <linux/user_namespace.h>
38 #include <linux/uprobes.h>
39 #include <linux/compat.h>
40 #include <linux/cn_proc.h>
41 #include <linux/compiler.h>
42 #include <linux/posix-timers.h>
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/signal.h>
47 #include <asm/param.h>
48 #include <linux/uaccess.h>
49 #include <asm/unistd.h>
50 #include <asm/siginfo.h>
51 #include <asm/cacheflush.h>
52 #include "audit.h" /* audit_signal_info() */
55 * SLAB caches for signal bits.
58 static struct kmem_cache
*sigqueue_cachep
;
60 int print_fatal_signals __read_mostly
;
62 static void __user
*sig_handler(struct task_struct
*t
, int sig
)
64 return t
->sighand
->action
[sig
- 1].sa
.sa_handler
;
67 static int sig_handler_ignored(void __user
*handler
, int sig
)
69 /* Is it explicitly or implicitly ignored? */
70 return handler
== SIG_IGN
||
71 (handler
== SIG_DFL
&& sig_kernel_ignore(sig
));
74 static int sig_task_ignored(struct task_struct
*t
, int sig
, bool force
)
78 handler
= sig_handler(t
, sig
);
80 if (unlikely(t
->signal
->flags
& SIGNAL_UNKILLABLE
) &&
81 handler
== SIG_DFL
&& !force
)
84 return sig_handler_ignored(handler
, sig
);
87 static int sig_ignored(struct task_struct
*t
, int sig
, bool force
)
90 * Blocked signals are never ignored, since the
91 * signal handler may change by the time it is
94 if (sigismember(&t
->blocked
, sig
) || sigismember(&t
->real_blocked
, sig
))
98 * Tracers may want to know about even ignored signal unless it
99 * is SIGKILL which can't be reported anyway but can be ignored
100 * by SIGNAL_UNKILLABLE task.
102 if (t
->ptrace
&& sig
!= SIGKILL
)
105 return sig_task_ignored(t
, sig
, force
);
109 * Re-calculate pending state from the set of locally pending
110 * signals, globally pending signals, and blocked signals.
112 static inline int has_pending_signals(sigset_t
*signal
, sigset_t
*blocked
)
117 switch (_NSIG_WORDS
) {
119 for (i
= _NSIG_WORDS
, ready
= 0; --i
>= 0 ;)
120 ready
|= signal
->sig
[i
] &~ blocked
->sig
[i
];
123 case 4: ready
= signal
->sig
[3] &~ blocked
->sig
[3];
124 ready
|= signal
->sig
[2] &~ blocked
->sig
[2];
125 ready
|= signal
->sig
[1] &~ blocked
->sig
[1];
126 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
129 case 2: ready
= signal
->sig
[1] &~ blocked
->sig
[1];
130 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
133 case 1: ready
= signal
->sig
[0] &~ blocked
->sig
[0];
138 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
140 static int recalc_sigpending_tsk(struct task_struct
*t
)
142 if ((t
->jobctl
& JOBCTL_PENDING_MASK
) ||
143 PENDING(&t
->pending
, &t
->blocked
) ||
144 PENDING(&t
->signal
->shared_pending
, &t
->blocked
)) {
145 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
149 * We must never clear the flag in another thread, or in current
150 * when it's possible the current syscall is returning -ERESTART*.
151 * So we don't clear it here, and only callers who know they should do.
157 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
158 * This is superfluous when called on current, the wakeup is a harmless no-op.
160 void recalc_sigpending_and_wake(struct task_struct
*t
)
162 if (recalc_sigpending_tsk(t
))
163 signal_wake_up(t
, 0);
166 void recalc_sigpending(void)
168 if (!recalc_sigpending_tsk(current
) && !freezing(current
))
169 clear_thread_flag(TIF_SIGPENDING
);
173 /* Given the mask, find the first available signal that should be serviced. */
175 #define SYNCHRONOUS_MASK \
176 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
177 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
179 int next_signal(struct sigpending
*pending
, sigset_t
*mask
)
181 unsigned long i
, *s
, *m
, x
;
184 s
= pending
->signal
.sig
;
188 * Handle the first word specially: it contains the
189 * synchronous signals that need to be dequeued first.
193 if (x
& SYNCHRONOUS_MASK
)
194 x
&= SYNCHRONOUS_MASK
;
199 switch (_NSIG_WORDS
) {
201 for (i
= 1; i
< _NSIG_WORDS
; ++i
) {
205 sig
= ffz(~x
) + i
*_NSIG_BPW
+ 1;
214 sig
= ffz(~x
) + _NSIG_BPW
+ 1;
225 static inline void print_dropped_signal(int sig
)
227 static DEFINE_RATELIMIT_STATE(ratelimit_state
, 5 * HZ
, 10);
229 if (!print_fatal_signals
)
232 if (!__ratelimit(&ratelimit_state
))
235 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
236 current
->comm
, current
->pid
, sig
);
240 * task_set_jobctl_pending - set jobctl pending bits
242 * @mask: pending bits to set
244 * Clear @mask from @task->jobctl. @mask must be subset of
245 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
246 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
247 * cleared. If @task is already being killed or exiting, this function
251 * Must be called with @task->sighand->siglock held.
254 * %true if @mask is set, %false if made noop because @task was dying.
256 bool task_set_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
258 BUG_ON(mask
& ~(JOBCTL_PENDING_MASK
| JOBCTL_STOP_CONSUME
|
259 JOBCTL_STOP_SIGMASK
| JOBCTL_TRAPPING
));
260 BUG_ON((mask
& JOBCTL_TRAPPING
) && !(mask
& JOBCTL_PENDING_MASK
));
262 if (unlikely(fatal_signal_pending(task
) || (task
->flags
& PF_EXITING
)))
265 if (mask
& JOBCTL_STOP_SIGMASK
)
266 task
->jobctl
&= ~JOBCTL_STOP_SIGMASK
;
268 task
->jobctl
|= mask
;
273 * task_clear_jobctl_trapping - clear jobctl trapping bit
276 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
277 * Clear it and wake up the ptracer. Note that we don't need any further
278 * locking. @task->siglock guarantees that @task->parent points to the
282 * Must be called with @task->sighand->siglock held.
284 void task_clear_jobctl_trapping(struct task_struct
*task
)
286 if (unlikely(task
->jobctl
& JOBCTL_TRAPPING
)) {
287 task
->jobctl
&= ~JOBCTL_TRAPPING
;
288 smp_mb(); /* advised by wake_up_bit() */
289 wake_up_bit(&task
->jobctl
, JOBCTL_TRAPPING_BIT
);
294 * task_clear_jobctl_pending - clear jobctl pending bits
296 * @mask: pending bits to clear
298 * Clear @mask from @task->jobctl. @mask must be subset of
299 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
300 * STOP bits are cleared together.
302 * If clearing of @mask leaves no stop or trap pending, this function calls
303 * task_clear_jobctl_trapping().
306 * Must be called with @task->sighand->siglock held.
308 void task_clear_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
310 BUG_ON(mask
& ~JOBCTL_PENDING_MASK
);
312 if (mask
& JOBCTL_STOP_PENDING
)
313 mask
|= JOBCTL_STOP_CONSUME
| JOBCTL_STOP_DEQUEUED
;
315 task
->jobctl
&= ~mask
;
317 if (!(task
->jobctl
& JOBCTL_PENDING_MASK
))
318 task_clear_jobctl_trapping(task
);
322 * task_participate_group_stop - participate in a group stop
323 * @task: task participating in a group stop
325 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
326 * Group stop states are cleared and the group stop count is consumed if
327 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
328 * stop, the appropriate %SIGNAL_* flags are set.
331 * Must be called with @task->sighand->siglock held.
334 * %true if group stop completion should be notified to the parent, %false
337 static bool task_participate_group_stop(struct task_struct
*task
)
339 struct signal_struct
*sig
= task
->signal
;
340 bool consume
= task
->jobctl
& JOBCTL_STOP_CONSUME
;
342 WARN_ON_ONCE(!(task
->jobctl
& JOBCTL_STOP_PENDING
));
344 task_clear_jobctl_pending(task
, JOBCTL_STOP_PENDING
);
349 if (!WARN_ON_ONCE(sig
->group_stop_count
== 0))
350 sig
->group_stop_count
--;
353 * Tell the caller to notify completion iff we are entering into a
354 * fresh group stop. Read comment in do_signal_stop() for details.
356 if (!sig
->group_stop_count
&& !(sig
->flags
& SIGNAL_STOP_STOPPED
)) {
357 signal_set_stop_flags(sig
, SIGNAL_STOP_STOPPED
);
364 * allocate a new signal queue record
365 * - this may be called without locks if and only if t == current, otherwise an
366 * appropriate lock must be held to stop the target task from exiting
368 static struct sigqueue
*
369 __sigqueue_alloc(int sig
, struct task_struct
*t
, gfp_t flags
, int override_rlimit
)
371 struct sigqueue
*q
= NULL
;
372 struct user_struct
*user
;
375 * Protect access to @t credentials. This can go away when all
376 * callers hold rcu read lock.
379 user
= get_uid(__task_cred(t
)->user
);
380 atomic_inc(&user
->sigpending
);
383 if (override_rlimit
||
384 atomic_read(&user
->sigpending
) <=
385 task_rlimit(t
, RLIMIT_SIGPENDING
)) {
386 q
= kmem_cache_alloc(sigqueue_cachep
, flags
);
388 print_dropped_signal(sig
);
391 if (unlikely(q
== NULL
)) {
392 atomic_dec(&user
->sigpending
);
395 INIT_LIST_HEAD(&q
->list
);
403 static void __sigqueue_free(struct sigqueue
*q
)
405 if (q
->flags
& SIGQUEUE_PREALLOC
)
407 atomic_dec(&q
->user
->sigpending
);
409 kmem_cache_free(sigqueue_cachep
, q
);
412 void flush_sigqueue(struct sigpending
*queue
)
416 sigemptyset(&queue
->signal
);
417 while (!list_empty(&queue
->list
)) {
418 q
= list_entry(queue
->list
.next
, struct sigqueue
, list
);
419 list_del_init(&q
->list
);
425 * Flush all pending signals for this kthread.
427 void flush_signals(struct task_struct
*t
)
431 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
432 clear_tsk_thread_flag(t
, TIF_SIGPENDING
);
433 flush_sigqueue(&t
->pending
);
434 flush_sigqueue(&t
->signal
->shared_pending
);
435 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
438 #ifdef CONFIG_POSIX_TIMERS
439 static void __flush_itimer_signals(struct sigpending
*pending
)
441 sigset_t signal
, retain
;
442 struct sigqueue
*q
, *n
;
444 signal
= pending
->signal
;
445 sigemptyset(&retain
);
447 list_for_each_entry_safe(q
, n
, &pending
->list
, list
) {
448 int sig
= q
->info
.si_signo
;
450 if (likely(q
->info
.si_code
!= SI_TIMER
)) {
451 sigaddset(&retain
, sig
);
453 sigdelset(&signal
, sig
);
454 list_del_init(&q
->list
);
459 sigorsets(&pending
->signal
, &signal
, &retain
);
462 void flush_itimer_signals(void)
464 struct task_struct
*tsk
= current
;
467 spin_lock_irqsave(&tsk
->sighand
->siglock
, flags
);
468 __flush_itimer_signals(&tsk
->pending
);
469 __flush_itimer_signals(&tsk
->signal
->shared_pending
);
470 spin_unlock_irqrestore(&tsk
->sighand
->siglock
, flags
);
474 void ignore_signals(struct task_struct
*t
)
478 for (i
= 0; i
< _NSIG
; ++i
)
479 t
->sighand
->action
[i
].sa
.sa_handler
= SIG_IGN
;
485 * Flush all handlers for a task.
489 flush_signal_handlers(struct task_struct
*t
, int force_default
)
492 struct k_sigaction
*ka
= &t
->sighand
->action
[0];
493 for (i
= _NSIG
; i
!= 0 ; i
--) {
494 if (force_default
|| ka
->sa
.sa_handler
!= SIG_IGN
)
495 ka
->sa
.sa_handler
= SIG_DFL
;
497 #ifdef __ARCH_HAS_SA_RESTORER
498 ka
->sa
.sa_restorer
= NULL
;
500 sigemptyset(&ka
->sa
.sa_mask
);
505 int unhandled_signal(struct task_struct
*tsk
, int sig
)
507 void __user
*handler
= tsk
->sighand
->action
[sig
-1].sa
.sa_handler
;
508 if (is_global_init(tsk
))
510 if (handler
!= SIG_IGN
&& handler
!= SIG_DFL
)
512 /* if ptraced, let the tracer determine */
516 static void collect_signal(int sig
, struct sigpending
*list
, siginfo_t
*info
,
519 struct sigqueue
*q
, *first
= NULL
;
522 * Collect the siginfo appropriate to this signal. Check if
523 * there is another siginfo for the same signal.
525 list_for_each_entry(q
, &list
->list
, list
) {
526 if (q
->info
.si_signo
== sig
) {
533 sigdelset(&list
->signal
, sig
);
537 list_del_init(&first
->list
);
538 copy_siginfo(info
, &first
->info
);
541 (first
->flags
& SIGQUEUE_PREALLOC
) &&
542 (info
->si_code
== SI_TIMER
) &&
543 (info
->si_sys_private
);
545 __sigqueue_free(first
);
548 * Ok, it wasn't in the queue. This must be
549 * a fast-pathed signal or we must have been
550 * out of queue space. So zero out the info.
552 info
->si_signo
= sig
;
554 info
->si_code
= SI_USER
;
560 static int __dequeue_signal(struct sigpending
*pending
, sigset_t
*mask
,
561 siginfo_t
*info
, bool *resched_timer
)
563 int sig
= next_signal(pending
, mask
);
566 collect_signal(sig
, pending
, info
, resched_timer
);
571 * Dequeue a signal and return the element to the caller, which is
572 * expected to free it.
574 * All callers have to hold the siglock.
576 int dequeue_signal(struct task_struct
*tsk
, sigset_t
*mask
, siginfo_t
*info
)
578 bool resched_timer
= false;
581 /* We only dequeue private signals from ourselves, we don't let
582 * signalfd steal them
584 signr
= __dequeue_signal(&tsk
->pending
, mask
, info
, &resched_timer
);
586 signr
= __dequeue_signal(&tsk
->signal
->shared_pending
,
587 mask
, info
, &resched_timer
);
588 #ifdef CONFIG_POSIX_TIMERS
592 * itimers are process shared and we restart periodic
593 * itimers in the signal delivery path to prevent DoS
594 * attacks in the high resolution timer case. This is
595 * compliant with the old way of self-restarting
596 * itimers, as the SIGALRM is a legacy signal and only
597 * queued once. Changing the restart behaviour to
598 * restart the timer in the signal dequeue path is
599 * reducing the timer noise on heavy loaded !highres
602 if (unlikely(signr
== SIGALRM
)) {
603 struct hrtimer
*tmr
= &tsk
->signal
->real_timer
;
605 if (!hrtimer_is_queued(tmr
) &&
606 tsk
->signal
->it_real_incr
!= 0) {
607 hrtimer_forward(tmr
, tmr
->base
->get_time(),
608 tsk
->signal
->it_real_incr
);
609 hrtimer_restart(tmr
);
619 if (unlikely(sig_kernel_stop(signr
))) {
621 * Set a marker that we have dequeued a stop signal. Our
622 * caller might release the siglock and then the pending
623 * stop signal it is about to process is no longer in the
624 * pending bitmasks, but must still be cleared by a SIGCONT
625 * (and overruled by a SIGKILL). So those cases clear this
626 * shared flag after we've set it. Note that this flag may
627 * remain set after the signal we return is ignored or
628 * handled. That doesn't matter because its only purpose
629 * is to alert stop-signal processing code when another
630 * processor has come along and cleared the flag.
632 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
634 #ifdef CONFIG_POSIX_TIMERS
637 * Release the siglock to ensure proper locking order
638 * of timer locks outside of siglocks. Note, we leave
639 * irqs disabled here, since the posix-timers code is
640 * about to disable them again anyway.
642 spin_unlock(&tsk
->sighand
->siglock
);
643 posixtimer_rearm(info
);
644 spin_lock(&tsk
->sighand
->siglock
);
651 * Tell a process that it has a new active signal..
653 * NOTE! we rely on the previous spin_lock to
654 * lock interrupts for us! We can only be called with
655 * "siglock" held, and the local interrupt must
656 * have been disabled when that got acquired!
658 * No need to set need_resched since signal event passing
659 * goes through ->blocked
661 void signal_wake_up_state(struct task_struct
*t
, unsigned int state
)
663 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
665 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
666 * case. We don't check t->state here because there is a race with it
667 * executing another processor and just now entering stopped state.
668 * By using wake_up_state, we ensure the process will wake up and
669 * handle its death signal.
671 if (!wake_up_state(t
, state
| TASK_INTERRUPTIBLE
))
676 * Remove signals in mask from the pending set and queue.
677 * Returns 1 if any signals were found.
679 * All callers must be holding the siglock.
681 static int flush_sigqueue_mask(sigset_t
*mask
, struct sigpending
*s
)
683 struct sigqueue
*q
, *n
;
686 sigandsets(&m
, mask
, &s
->signal
);
687 if (sigisemptyset(&m
))
690 sigandnsets(&s
->signal
, &s
->signal
, mask
);
691 list_for_each_entry_safe(q
, n
, &s
->list
, list
) {
692 if (sigismember(mask
, q
->info
.si_signo
)) {
693 list_del_init(&q
->list
);
700 static inline int is_si_special(const struct siginfo
*info
)
702 return info
<= SEND_SIG_FORCED
;
705 static inline bool si_fromuser(const struct siginfo
*info
)
707 return info
== SEND_SIG_NOINFO
||
708 (!is_si_special(info
) && SI_FROMUSER(info
));
712 * called with RCU read lock from check_kill_permission()
714 static int kill_ok_by_cred(struct task_struct
*t
)
716 const struct cred
*cred
= current_cred();
717 const struct cred
*tcred
= __task_cred(t
);
719 if (uid_eq(cred
->euid
, tcred
->suid
) ||
720 uid_eq(cred
->euid
, tcred
->uid
) ||
721 uid_eq(cred
->uid
, tcred
->suid
) ||
722 uid_eq(cred
->uid
, tcred
->uid
))
725 if (ns_capable(tcred
->user_ns
, CAP_KILL
))
732 * Bad permissions for sending the signal
733 * - the caller must hold the RCU read lock
735 static int check_kill_permission(int sig
, struct siginfo
*info
,
736 struct task_struct
*t
)
741 if (!valid_signal(sig
))
744 if (!si_fromuser(info
))
747 error
= audit_signal_info(sig
, t
); /* Let audit system see the signal */
751 if (!same_thread_group(current
, t
) &&
752 !kill_ok_by_cred(t
)) {
755 sid
= task_session(t
);
757 * We don't return the error if sid == NULL. The
758 * task was unhashed, the caller must notice this.
760 if (!sid
|| sid
== task_session(current
))
767 return security_task_kill(t
, info
, sig
, 0);
771 * ptrace_trap_notify - schedule trap to notify ptracer
772 * @t: tracee wanting to notify tracer
774 * This function schedules sticky ptrace trap which is cleared on the next
775 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
778 * If @t is running, STOP trap will be taken. If trapped for STOP and
779 * ptracer is listening for events, tracee is woken up so that it can
780 * re-trap for the new event. If trapped otherwise, STOP trap will be
781 * eventually taken without returning to userland after the existing traps
782 * are finished by PTRACE_CONT.
785 * Must be called with @task->sighand->siglock held.
787 static void ptrace_trap_notify(struct task_struct
*t
)
789 WARN_ON_ONCE(!(t
->ptrace
& PT_SEIZED
));
790 assert_spin_locked(&t
->sighand
->siglock
);
792 task_set_jobctl_pending(t
, JOBCTL_TRAP_NOTIFY
);
793 ptrace_signal_wake_up(t
, t
->jobctl
& JOBCTL_LISTENING
);
797 * Handle magic process-wide effects of stop/continue signals. Unlike
798 * the signal actions, these happen immediately at signal-generation
799 * time regardless of blocking, ignoring, or handling. This does the
800 * actual continuing for SIGCONT, but not the actual stopping for stop
801 * signals. The process stop is done as a signal action for SIG_DFL.
803 * Returns true if the signal should be actually delivered, otherwise
804 * it should be dropped.
806 static bool prepare_signal(int sig
, struct task_struct
*p
, bool force
)
808 struct signal_struct
*signal
= p
->signal
;
809 struct task_struct
*t
;
812 if (signal
->flags
& (SIGNAL_GROUP_EXIT
| SIGNAL_GROUP_COREDUMP
)) {
813 if (!(signal
->flags
& SIGNAL_GROUP_EXIT
))
814 return sig
== SIGKILL
;
816 * The process is in the middle of dying, nothing to do.
818 } else if (sig_kernel_stop(sig
)) {
820 * This is a stop signal. Remove SIGCONT from all queues.
822 siginitset(&flush
, sigmask(SIGCONT
));
823 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
824 for_each_thread(p
, t
)
825 flush_sigqueue_mask(&flush
, &t
->pending
);
826 } else if (sig
== SIGCONT
) {
829 * Remove all stop signals from all queues, wake all threads.
831 siginitset(&flush
, SIG_KERNEL_STOP_MASK
);
832 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
833 for_each_thread(p
, t
) {
834 flush_sigqueue_mask(&flush
, &t
->pending
);
835 task_clear_jobctl_pending(t
, JOBCTL_STOP_PENDING
);
836 if (likely(!(t
->ptrace
& PT_SEIZED
)))
837 wake_up_state(t
, __TASK_STOPPED
);
839 ptrace_trap_notify(t
);
843 * Notify the parent with CLD_CONTINUED if we were stopped.
845 * If we were in the middle of a group stop, we pretend it
846 * was already finished, and then continued. Since SIGCHLD
847 * doesn't queue we report only CLD_STOPPED, as if the next
848 * CLD_CONTINUED was dropped.
851 if (signal
->flags
& SIGNAL_STOP_STOPPED
)
852 why
|= SIGNAL_CLD_CONTINUED
;
853 else if (signal
->group_stop_count
)
854 why
|= SIGNAL_CLD_STOPPED
;
858 * The first thread which returns from do_signal_stop()
859 * will take ->siglock, notice SIGNAL_CLD_MASK, and
860 * notify its parent. See get_signal_to_deliver().
862 signal_set_stop_flags(signal
, why
| SIGNAL_STOP_CONTINUED
);
863 signal
->group_stop_count
= 0;
864 signal
->group_exit_code
= 0;
868 return !sig_ignored(p
, sig
, force
);
872 * Test if P wants to take SIG. After we've checked all threads with this,
873 * it's equivalent to finding no threads not blocking SIG. Any threads not
874 * blocking SIG were ruled out because they are not running and already
875 * have pending signals. Such threads will dequeue from the shared queue
876 * as soon as they're available, so putting the signal on the shared queue
877 * will be equivalent to sending it to one such thread.
879 static inline int wants_signal(int sig
, struct task_struct
*p
)
881 if (sigismember(&p
->blocked
, sig
))
883 if (p
->flags
& PF_EXITING
)
887 if (task_is_stopped_or_traced(p
))
889 return task_curr(p
) || !signal_pending(p
);
892 static void complete_signal(int sig
, struct task_struct
*p
, int group
)
894 struct signal_struct
*signal
= p
->signal
;
895 struct task_struct
*t
;
898 * Now find a thread we can wake up to take the signal off the queue.
900 * If the main thread wants the signal, it gets first crack.
901 * Probably the least surprising to the average bear.
903 if (wants_signal(sig
, p
))
905 else if (!group
|| thread_group_empty(p
))
907 * There is just one thread and it does not need to be woken.
908 * It will dequeue unblocked signals before it runs again.
913 * Otherwise try to find a suitable thread.
915 t
= signal
->curr_target
;
916 while (!wants_signal(sig
, t
)) {
918 if (t
== signal
->curr_target
)
920 * No thread needs to be woken.
921 * Any eligible threads will see
922 * the signal in the queue soon.
926 signal
->curr_target
= t
;
930 * Found a killable thread. If the signal will be fatal,
931 * then start taking the whole group down immediately.
933 if (sig_fatal(p
, sig
) &&
934 !(signal
->flags
& (SIGNAL_UNKILLABLE
| SIGNAL_GROUP_EXIT
)) &&
935 !sigismember(&t
->real_blocked
, sig
) &&
936 (sig
== SIGKILL
|| !t
->ptrace
)) {
938 * This signal will be fatal to the whole group.
940 if (!sig_kernel_coredump(sig
)) {
942 * Start a group exit and wake everybody up.
943 * This way we don't have other threads
944 * running and doing things after a slower
945 * thread has the fatal signal pending.
947 signal
->flags
= SIGNAL_GROUP_EXIT
;
948 signal
->group_exit_code
= sig
;
949 signal
->group_stop_count
= 0;
952 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
953 sigaddset(&t
->pending
.signal
, SIGKILL
);
954 signal_wake_up(t
, 1);
955 } while_each_thread(p
, t
);
961 * The signal is already in the shared-pending queue.
962 * Tell the chosen thread to wake up and dequeue it.
964 signal_wake_up(t
, sig
== SIGKILL
);
968 static inline int legacy_queue(struct sigpending
*signals
, int sig
)
970 return (sig
< SIGRTMIN
) && sigismember(&signals
->signal
, sig
);
973 #ifdef CONFIG_USER_NS
974 static inline void userns_fixup_signal_uid(struct siginfo
*info
, struct task_struct
*t
)
976 if (current_user_ns() == task_cred_xxx(t
, user_ns
))
979 if (SI_FROMKERNEL(info
))
983 info
->si_uid
= from_kuid_munged(task_cred_xxx(t
, user_ns
),
984 make_kuid(current_user_ns(), info
->si_uid
));
988 static inline void userns_fixup_signal_uid(struct siginfo
*info
, struct task_struct
*t
)
994 static int __send_signal(int sig
, struct siginfo
*info
, struct task_struct
*t
,
995 int group
, int from_ancestor_ns
)
997 struct sigpending
*pending
;
1000 int ret
= 0, result
;
1002 assert_spin_locked(&t
->sighand
->siglock
);
1004 result
= TRACE_SIGNAL_IGNORED
;
1005 if (!prepare_signal(sig
, t
,
1006 from_ancestor_ns
|| (info
== SEND_SIG_FORCED
)))
1009 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
1011 * Short-circuit ignored signals and support queuing
1012 * exactly one non-rt signal, so that we can get more
1013 * detailed information about the cause of the signal.
1015 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1016 if (legacy_queue(pending
, sig
))
1019 result
= TRACE_SIGNAL_DELIVERED
;
1021 * fast-pathed signals for kernel-internal things like SIGSTOP
1024 if (info
== SEND_SIG_FORCED
)
1028 * Real-time signals must be queued if sent by sigqueue, or
1029 * some other real-time mechanism. It is implementation
1030 * defined whether kill() does so. We attempt to do so, on
1031 * the principle of least surprise, but since kill is not
1032 * allowed to fail with EAGAIN when low on memory we just
1033 * make sure at least one signal gets delivered and don't
1034 * pass on the info struct.
1037 override_rlimit
= (is_si_special(info
) || info
->si_code
>= 0);
1039 override_rlimit
= 0;
1041 q
= __sigqueue_alloc(sig
, t
, GFP_ATOMIC
, override_rlimit
);
1043 list_add_tail(&q
->list
, &pending
->list
);
1044 switch ((unsigned long) info
) {
1045 case (unsigned long) SEND_SIG_NOINFO
:
1046 q
->info
.si_signo
= sig
;
1047 q
->info
.si_errno
= 0;
1048 q
->info
.si_code
= SI_USER
;
1049 q
->info
.si_pid
= task_tgid_nr_ns(current
,
1050 task_active_pid_ns(t
));
1051 q
->info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
1053 case (unsigned long) SEND_SIG_PRIV
:
1054 q
->info
.si_signo
= sig
;
1055 q
->info
.si_errno
= 0;
1056 q
->info
.si_code
= SI_KERNEL
;
1061 copy_siginfo(&q
->info
, info
);
1062 if (from_ancestor_ns
)
1067 userns_fixup_signal_uid(&q
->info
, t
);
1069 } else if (!is_si_special(info
)) {
1070 if (sig
>= SIGRTMIN
&& info
->si_code
!= SI_USER
) {
1072 * Queue overflow, abort. We may abort if the
1073 * signal was rt and sent by user using something
1074 * other than kill().
1076 result
= TRACE_SIGNAL_OVERFLOW_FAIL
;
1081 * This is a silent loss of information. We still
1082 * send the signal, but the *info bits are lost.
1084 result
= TRACE_SIGNAL_LOSE_INFO
;
1089 signalfd_notify(t
, sig
);
1090 sigaddset(&pending
->signal
, sig
);
1091 complete_signal(sig
, t
, group
);
1093 trace_signal_generate(sig
, info
, t
, group
, result
);
1097 static int send_signal(int sig
, struct siginfo
*info
, struct task_struct
*t
,
1100 int from_ancestor_ns
= 0;
1102 #ifdef CONFIG_PID_NS
1103 from_ancestor_ns
= si_fromuser(info
) &&
1104 !task_pid_nr_ns(current
, task_active_pid_ns(t
));
1107 return __send_signal(sig
, info
, t
, group
, from_ancestor_ns
);
1110 static void print_fatal_signal(int signr
)
1112 struct pt_regs
*regs
= signal_pt_regs();
1113 pr_info("potentially unexpected fatal signal %d.\n", signr
);
1115 #if defined(__i386__) && !defined(__arch_um__)
1116 pr_info("code at %08lx: ", regs
->ip
);
1119 for (i
= 0; i
< 16; i
++) {
1122 if (get_user(insn
, (unsigned char *)(regs
->ip
+ i
)))
1124 pr_cont("%02x ", insn
);
1134 static int __init
setup_print_fatal_signals(char *str
)
1136 get_option (&str
, &print_fatal_signals
);
1141 __setup("print-fatal-signals=", setup_print_fatal_signals
);
1144 __group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1146 return send_signal(sig
, info
, p
, 1);
1150 specific_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
1152 return send_signal(sig
, info
, t
, 0);
1155 int do_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
,
1158 unsigned long flags
;
1161 if (lock_task_sighand(p
, &flags
)) {
1162 ret
= send_signal(sig
, info
, p
, group
);
1163 unlock_task_sighand(p
, &flags
);
1170 * Force a signal that the process can't ignore: if necessary
1171 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1173 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1174 * since we do not want to have a signal handler that was blocked
1175 * be invoked when user space had explicitly blocked it.
1177 * We don't want to have recursive SIGSEGV's etc, for example,
1178 * that is why we also clear SIGNAL_UNKILLABLE.
1181 force_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
1183 unsigned long int flags
;
1184 int ret
, blocked
, ignored
;
1185 struct k_sigaction
*action
;
1187 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
1188 action
= &t
->sighand
->action
[sig
-1];
1189 ignored
= action
->sa
.sa_handler
== SIG_IGN
;
1190 blocked
= sigismember(&t
->blocked
, sig
);
1191 if (blocked
|| ignored
) {
1192 action
->sa
.sa_handler
= SIG_DFL
;
1194 sigdelset(&t
->blocked
, sig
);
1195 recalc_sigpending_and_wake(t
);
1199 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1200 * debugging to leave init killable.
1202 if (action
->sa
.sa_handler
== SIG_DFL
&& !t
->ptrace
)
1203 t
->signal
->flags
&= ~SIGNAL_UNKILLABLE
;
1204 ret
= specific_send_sig_info(sig
, info
, t
);
1205 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
1211 * Nuke all other threads in the group.
1213 int zap_other_threads(struct task_struct
*p
)
1215 struct task_struct
*t
= p
;
1218 p
->signal
->group_stop_count
= 0;
1220 while_each_thread(p
, t
) {
1221 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
1224 /* Don't bother with already dead threads */
1227 sigaddset(&t
->pending
.signal
, SIGKILL
);
1228 signal_wake_up(t
, 1);
1234 struct sighand_struct
*__lock_task_sighand(struct task_struct
*tsk
,
1235 unsigned long *flags
)
1237 struct sighand_struct
*sighand
;
1241 * Disable interrupts early to avoid deadlocks.
1242 * See rcu_read_unlock() comment header for details.
1244 local_irq_save(*flags
);
1246 sighand
= rcu_dereference(tsk
->sighand
);
1247 if (unlikely(sighand
== NULL
)) {
1249 local_irq_restore(*flags
);
1253 * This sighand can be already freed and even reused, but
1254 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1255 * initializes ->siglock: this slab can't go away, it has
1256 * the same object type, ->siglock can't be reinitialized.
1258 * We need to ensure that tsk->sighand is still the same
1259 * after we take the lock, we can race with de_thread() or
1260 * __exit_signal(). In the latter case the next iteration
1261 * must see ->sighand == NULL.
1263 spin_lock(&sighand
->siglock
);
1264 if (likely(sighand
== tsk
->sighand
)) {
1268 spin_unlock(&sighand
->siglock
);
1270 local_irq_restore(*flags
);
1277 * send signal info to all the members of a group
1279 int group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1284 ret
= check_kill_permission(sig
, info
, p
);
1288 ret
= do_send_sig_info(sig
, info
, p
, true);
1294 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1295 * control characters do (^C, ^Z etc)
1296 * - the caller must hold at least a readlock on tasklist_lock
1298 int __kill_pgrp_info(int sig
, struct siginfo
*info
, struct pid
*pgrp
)
1300 struct task_struct
*p
= NULL
;
1301 int retval
, success
;
1305 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
1306 int err
= group_send_sig_info(sig
, info
, p
);
1309 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
1310 return success
? 0 : retval
;
1313 int kill_pid_info(int sig
, struct siginfo
*info
, struct pid
*pid
)
1316 struct task_struct
*p
;
1320 p
= pid_task(pid
, PIDTYPE_PID
);
1322 error
= group_send_sig_info(sig
, info
, p
);
1324 if (likely(!p
|| error
!= -ESRCH
))
1328 * The task was unhashed in between, try again. If it
1329 * is dead, pid_task() will return NULL, if we race with
1330 * de_thread() it will find the new leader.
1335 static int kill_proc_info(int sig
, struct siginfo
*info
, pid_t pid
)
1339 error
= kill_pid_info(sig
, info
, find_vpid(pid
));
1344 static int kill_as_cred_perm(const struct cred
*cred
,
1345 struct task_struct
*target
)
1347 const struct cred
*pcred
= __task_cred(target
);
1348 if (!uid_eq(cred
->euid
, pcred
->suid
) && !uid_eq(cred
->euid
, pcred
->uid
) &&
1349 !uid_eq(cred
->uid
, pcred
->suid
) && !uid_eq(cred
->uid
, pcred
->uid
))
1354 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1355 int kill_pid_info_as_cred(int sig
, struct siginfo
*info
, struct pid
*pid
,
1356 const struct cred
*cred
, u32 secid
)
1359 struct task_struct
*p
;
1360 unsigned long flags
;
1362 if (!valid_signal(sig
))
1366 p
= pid_task(pid
, PIDTYPE_PID
);
1371 if (si_fromuser(info
) && !kill_as_cred_perm(cred
, p
)) {
1375 ret
= security_task_kill(p
, info
, sig
, secid
);
1380 if (lock_task_sighand(p
, &flags
)) {
1381 ret
= __send_signal(sig
, info
, p
, 1, 0);
1382 unlock_task_sighand(p
, &flags
);
1390 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred
);
1393 * kill_something_info() interprets pid in interesting ways just like kill(2).
1395 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1396 * is probably wrong. Should make it like BSD or SYSV.
1399 static int kill_something_info(int sig
, struct siginfo
*info
, pid_t pid
)
1405 ret
= kill_pid_info(sig
, info
, find_vpid(pid
));
1410 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1414 read_lock(&tasklist_lock
);
1416 ret
= __kill_pgrp_info(sig
, info
,
1417 pid
? find_vpid(-pid
) : task_pgrp(current
));
1419 int retval
= 0, count
= 0;
1420 struct task_struct
* p
;
1422 for_each_process(p
) {
1423 if (task_pid_vnr(p
) > 1 &&
1424 !same_thread_group(p
, current
)) {
1425 int err
= group_send_sig_info(sig
, info
, p
);
1431 ret
= count
? retval
: -ESRCH
;
1433 read_unlock(&tasklist_lock
);
1439 * These are for backward compatibility with the rest of the kernel source.
1442 int send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1445 * Make sure legacy kernel users don't send in bad values
1446 * (normal paths check this in check_kill_permission).
1448 if (!valid_signal(sig
))
1451 return do_send_sig_info(sig
, info
, p
, false);
1454 #define __si_special(priv) \
1455 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1458 send_sig(int sig
, struct task_struct
*p
, int priv
)
1460 return send_sig_info(sig
, __si_special(priv
), p
);
1464 force_sig(int sig
, struct task_struct
*p
)
1466 force_sig_info(sig
, SEND_SIG_PRIV
, p
);
1470 * When things go south during signal handling, we
1471 * will force a SIGSEGV. And if the signal that caused
1472 * the problem was already a SIGSEGV, we'll want to
1473 * make sure we don't even try to deliver the signal..
1476 force_sigsegv(int sig
, struct task_struct
*p
)
1478 if (sig
== SIGSEGV
) {
1479 unsigned long flags
;
1480 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
1481 p
->sighand
->action
[sig
- 1].sa
.sa_handler
= SIG_DFL
;
1482 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
1484 force_sig(SIGSEGV
, p
);
1488 int kill_pgrp(struct pid
*pid
, int sig
, int priv
)
1492 read_lock(&tasklist_lock
);
1493 ret
= __kill_pgrp_info(sig
, __si_special(priv
), pid
);
1494 read_unlock(&tasklist_lock
);
1498 EXPORT_SYMBOL(kill_pgrp
);
1500 int kill_pid(struct pid
*pid
, int sig
, int priv
)
1502 return kill_pid_info(sig
, __si_special(priv
), pid
);
1504 EXPORT_SYMBOL(kill_pid
);
1507 * These functions support sending signals using preallocated sigqueue
1508 * structures. This is needed "because realtime applications cannot
1509 * afford to lose notifications of asynchronous events, like timer
1510 * expirations or I/O completions". In the case of POSIX Timers
1511 * we allocate the sigqueue structure from the timer_create. If this
1512 * allocation fails we are able to report the failure to the application
1513 * with an EAGAIN error.
1515 struct sigqueue
*sigqueue_alloc(void)
1517 struct sigqueue
*q
= __sigqueue_alloc(-1, current
, GFP_KERNEL
, 0);
1520 q
->flags
|= SIGQUEUE_PREALLOC
;
1525 void sigqueue_free(struct sigqueue
*q
)
1527 unsigned long flags
;
1528 spinlock_t
*lock
= ¤t
->sighand
->siglock
;
1530 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1532 * We must hold ->siglock while testing q->list
1533 * to serialize with collect_signal() or with
1534 * __exit_signal()->flush_sigqueue().
1536 spin_lock_irqsave(lock
, flags
);
1537 q
->flags
&= ~SIGQUEUE_PREALLOC
;
1539 * If it is queued it will be freed when dequeued,
1540 * like the "regular" sigqueue.
1542 if (!list_empty(&q
->list
))
1544 spin_unlock_irqrestore(lock
, flags
);
1550 int send_sigqueue(struct sigqueue
*q
, struct task_struct
*t
, int group
)
1552 int sig
= q
->info
.si_signo
;
1553 struct sigpending
*pending
;
1554 unsigned long flags
;
1557 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1560 if (!likely(lock_task_sighand(t
, &flags
)))
1563 ret
= 1; /* the signal is ignored */
1564 result
= TRACE_SIGNAL_IGNORED
;
1565 if (!prepare_signal(sig
, t
, false))
1569 if (unlikely(!list_empty(&q
->list
))) {
1571 * If an SI_TIMER entry is already queue just increment
1572 * the overrun count.
1574 BUG_ON(q
->info
.si_code
!= SI_TIMER
);
1575 q
->info
.si_overrun
++;
1576 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1579 q
->info
.si_overrun
= 0;
1581 signalfd_notify(t
, sig
);
1582 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
1583 list_add_tail(&q
->list
, &pending
->list
);
1584 sigaddset(&pending
->signal
, sig
);
1585 complete_signal(sig
, t
, group
);
1586 result
= TRACE_SIGNAL_DELIVERED
;
1588 trace_signal_generate(sig
, &q
->info
, t
, group
, result
);
1589 unlock_task_sighand(t
, &flags
);
1595 * Let a parent know about the death of a child.
1596 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1598 * Returns true if our parent ignored us and so we've switched to
1601 bool do_notify_parent(struct task_struct
*tsk
, int sig
)
1603 struct siginfo info
;
1604 unsigned long flags
;
1605 struct sighand_struct
*psig
;
1606 bool autoreap
= false;
1611 /* do_notify_parent_cldstop should have been called instead. */
1612 BUG_ON(task_is_stopped_or_traced(tsk
));
1614 BUG_ON(!tsk
->ptrace
&&
1615 (tsk
->group_leader
!= tsk
|| !thread_group_empty(tsk
)));
1617 if (sig
!= SIGCHLD
) {
1619 * This is only possible if parent == real_parent.
1620 * Check if it has changed security domain.
1622 if (tsk
->parent_exec_id
!= tsk
->parent
->self_exec_id
)
1626 info
.si_signo
= sig
;
1629 * We are under tasklist_lock here so our parent is tied to
1630 * us and cannot change.
1632 * task_active_pid_ns will always return the same pid namespace
1633 * until a task passes through release_task.
1635 * write_lock() currently calls preempt_disable() which is the
1636 * same as rcu_read_lock(), but according to Oleg, this is not
1637 * correct to rely on this
1640 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(tsk
->parent
));
1641 info
.si_uid
= from_kuid_munged(task_cred_xxx(tsk
->parent
, user_ns
),
1645 task_cputime(tsk
, &utime
, &stime
);
1646 info
.si_utime
= nsec_to_clock_t(utime
+ tsk
->signal
->utime
);
1647 info
.si_stime
= nsec_to_clock_t(stime
+ tsk
->signal
->stime
);
1649 info
.si_status
= tsk
->exit_code
& 0x7f;
1650 if (tsk
->exit_code
& 0x80)
1651 info
.si_code
= CLD_DUMPED
;
1652 else if (tsk
->exit_code
& 0x7f)
1653 info
.si_code
= CLD_KILLED
;
1655 info
.si_code
= CLD_EXITED
;
1656 info
.si_status
= tsk
->exit_code
>> 8;
1659 psig
= tsk
->parent
->sighand
;
1660 spin_lock_irqsave(&psig
->siglock
, flags
);
1661 if (!tsk
->ptrace
&& sig
== SIGCHLD
&&
1662 (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
||
1663 (psig
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDWAIT
))) {
1665 * We are exiting and our parent doesn't care. POSIX.1
1666 * defines special semantics for setting SIGCHLD to SIG_IGN
1667 * or setting the SA_NOCLDWAIT flag: we should be reaped
1668 * automatically and not left for our parent's wait4 call.
1669 * Rather than having the parent do it as a magic kind of
1670 * signal handler, we just set this to tell do_exit that we
1671 * can be cleaned up without becoming a zombie. Note that
1672 * we still call __wake_up_parent in this case, because a
1673 * blocked sys_wait4 might now return -ECHILD.
1675 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1676 * is implementation-defined: we do (if you don't want
1677 * it, just use SIG_IGN instead).
1680 if (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
)
1683 if (valid_signal(sig
) && sig
)
1684 __group_send_sig_info(sig
, &info
, tsk
->parent
);
1685 __wake_up_parent(tsk
, tsk
->parent
);
1686 spin_unlock_irqrestore(&psig
->siglock
, flags
);
1692 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1693 * @tsk: task reporting the state change
1694 * @for_ptracer: the notification is for ptracer
1695 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1697 * Notify @tsk's parent that the stopped/continued state has changed. If
1698 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1699 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1702 * Must be called with tasklist_lock at least read locked.
1704 static void do_notify_parent_cldstop(struct task_struct
*tsk
,
1705 bool for_ptracer
, int why
)
1707 struct siginfo info
;
1708 unsigned long flags
;
1709 struct task_struct
*parent
;
1710 struct sighand_struct
*sighand
;
1714 parent
= tsk
->parent
;
1716 tsk
= tsk
->group_leader
;
1717 parent
= tsk
->real_parent
;
1720 info
.si_signo
= SIGCHLD
;
1723 * see comment in do_notify_parent() about the following 4 lines
1726 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(parent
));
1727 info
.si_uid
= from_kuid_munged(task_cred_xxx(parent
, user_ns
), task_uid(tsk
));
1730 task_cputime(tsk
, &utime
, &stime
);
1731 info
.si_utime
= nsec_to_clock_t(utime
);
1732 info
.si_stime
= nsec_to_clock_t(stime
);
1737 info
.si_status
= SIGCONT
;
1740 info
.si_status
= tsk
->signal
->group_exit_code
& 0x7f;
1743 info
.si_status
= tsk
->exit_code
& 0x7f;
1749 sighand
= parent
->sighand
;
1750 spin_lock_irqsave(&sighand
->siglock
, flags
);
1751 if (sighand
->action
[SIGCHLD
-1].sa
.sa_handler
!= SIG_IGN
&&
1752 !(sighand
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDSTOP
))
1753 __group_send_sig_info(SIGCHLD
, &info
, parent
);
1755 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1757 __wake_up_parent(tsk
, parent
);
1758 spin_unlock_irqrestore(&sighand
->siglock
, flags
);
1761 static inline int may_ptrace_stop(void)
1763 if (!likely(current
->ptrace
))
1766 * Are we in the middle of do_coredump?
1767 * If so and our tracer is also part of the coredump stopping
1768 * is a deadlock situation, and pointless because our tracer
1769 * is dead so don't allow us to stop.
1770 * If SIGKILL was already sent before the caller unlocked
1771 * ->siglock we must see ->core_state != NULL. Otherwise it
1772 * is safe to enter schedule().
1774 * This is almost outdated, a task with the pending SIGKILL can't
1775 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1776 * after SIGKILL was already dequeued.
1778 if (unlikely(current
->mm
->core_state
) &&
1779 unlikely(current
->mm
== current
->parent
->mm
))
1786 * Return non-zero if there is a SIGKILL that should be waking us up.
1787 * Called with the siglock held.
1789 static int sigkill_pending(struct task_struct
*tsk
)
1791 return sigismember(&tsk
->pending
.signal
, SIGKILL
) ||
1792 sigismember(&tsk
->signal
->shared_pending
.signal
, SIGKILL
);
1796 * This must be called with current->sighand->siglock held.
1798 * This should be the path for all ptrace stops.
1799 * We always set current->last_siginfo while stopped here.
1800 * That makes it a way to test a stopped process for
1801 * being ptrace-stopped vs being job-control-stopped.
1803 * If we actually decide not to stop at all because the tracer
1804 * is gone, we keep current->exit_code unless clear_code.
1806 static void ptrace_stop(int exit_code
, int why
, int clear_code
, siginfo_t
*info
)
1807 __releases(¤t
->sighand
->siglock
)
1808 __acquires(¤t
->sighand
->siglock
)
1810 bool gstop_done
= false;
1812 if (arch_ptrace_stop_needed(exit_code
, info
)) {
1814 * The arch code has something special to do before a
1815 * ptrace stop. This is allowed to block, e.g. for faults
1816 * on user stack pages. We can't keep the siglock while
1817 * calling arch_ptrace_stop, so we must release it now.
1818 * To preserve proper semantics, we must do this before
1819 * any signal bookkeeping like checking group_stop_count.
1820 * Meanwhile, a SIGKILL could come in before we retake the
1821 * siglock. That must prevent us from sleeping in TASK_TRACED.
1822 * So after regaining the lock, we must check for SIGKILL.
1824 spin_unlock_irq(¤t
->sighand
->siglock
);
1825 arch_ptrace_stop(exit_code
, info
);
1826 spin_lock_irq(¤t
->sighand
->siglock
);
1827 if (sigkill_pending(current
))
1832 * We're committing to trapping. TRACED should be visible before
1833 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1834 * Also, transition to TRACED and updates to ->jobctl should be
1835 * atomic with respect to siglock and should be done after the arch
1836 * hook as siglock is released and regrabbed across it.
1838 set_current_state(TASK_TRACED
);
1840 current
->last_siginfo
= info
;
1841 current
->exit_code
= exit_code
;
1844 * If @why is CLD_STOPPED, we're trapping to participate in a group
1845 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1846 * across siglock relocks since INTERRUPT was scheduled, PENDING
1847 * could be clear now. We act as if SIGCONT is received after
1848 * TASK_TRACED is entered - ignore it.
1850 if (why
== CLD_STOPPED
&& (current
->jobctl
& JOBCTL_STOP_PENDING
))
1851 gstop_done
= task_participate_group_stop(current
);
1853 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1854 task_clear_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
1855 if (info
&& info
->si_code
>> 8 == PTRACE_EVENT_STOP
)
1856 task_clear_jobctl_pending(current
, JOBCTL_TRAP_NOTIFY
);
1858 /* entering a trap, clear TRAPPING */
1859 task_clear_jobctl_trapping(current
);
1861 spin_unlock_irq(¤t
->sighand
->siglock
);
1862 read_lock(&tasklist_lock
);
1863 if (may_ptrace_stop()) {
1865 * Notify parents of the stop.
1867 * While ptraced, there are two parents - the ptracer and
1868 * the real_parent of the group_leader. The ptracer should
1869 * know about every stop while the real parent is only
1870 * interested in the completion of group stop. The states
1871 * for the two don't interact with each other. Notify
1872 * separately unless they're gonna be duplicates.
1874 do_notify_parent_cldstop(current
, true, why
);
1875 if (gstop_done
&& ptrace_reparented(current
))
1876 do_notify_parent_cldstop(current
, false, why
);
1879 * Don't want to allow preemption here, because
1880 * sys_ptrace() needs this task to be inactive.
1882 * XXX: implement read_unlock_no_resched().
1885 read_unlock(&tasklist_lock
);
1886 preempt_enable_no_resched();
1887 freezable_schedule();
1890 * By the time we got the lock, our tracer went away.
1891 * Don't drop the lock yet, another tracer may come.
1893 * If @gstop_done, the ptracer went away between group stop
1894 * completion and here. During detach, it would have set
1895 * JOBCTL_STOP_PENDING on us and we'll re-enter
1896 * TASK_STOPPED in do_signal_stop() on return, so notifying
1897 * the real parent of the group stop completion is enough.
1900 do_notify_parent_cldstop(current
, false, why
);
1902 /* tasklist protects us from ptrace_freeze_traced() */
1903 __set_current_state(TASK_RUNNING
);
1905 current
->exit_code
= 0;
1906 read_unlock(&tasklist_lock
);
1910 * We are back. Now reacquire the siglock before touching
1911 * last_siginfo, so that we are sure to have synchronized with
1912 * any signal-sending on another CPU that wants to examine it.
1914 spin_lock_irq(¤t
->sighand
->siglock
);
1915 current
->last_siginfo
= NULL
;
1917 /* LISTENING can be set only during STOP traps, clear it */
1918 current
->jobctl
&= ~JOBCTL_LISTENING
;
1921 * Queued signals ignored us while we were stopped for tracing.
1922 * So check for any that we should take before resuming user mode.
1923 * This sets TIF_SIGPENDING, but never clears it.
1925 recalc_sigpending_tsk(current
);
1928 static void ptrace_do_notify(int signr
, int exit_code
, int why
)
1932 memset(&info
, 0, sizeof info
);
1933 info
.si_signo
= signr
;
1934 info
.si_code
= exit_code
;
1935 info
.si_pid
= task_pid_vnr(current
);
1936 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
1938 /* Let the debugger run. */
1939 ptrace_stop(exit_code
, why
, 1, &info
);
1942 void ptrace_notify(int exit_code
)
1944 BUG_ON((exit_code
& (0x7f | ~0xffff)) != SIGTRAP
);
1945 if (unlikely(current
->task_works
))
1948 spin_lock_irq(¤t
->sighand
->siglock
);
1949 ptrace_do_notify(SIGTRAP
, exit_code
, CLD_TRAPPED
);
1950 spin_unlock_irq(¤t
->sighand
->siglock
);
1954 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1955 * @signr: signr causing group stop if initiating
1957 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1958 * and participate in it. If already set, participate in the existing
1959 * group stop. If participated in a group stop (and thus slept), %true is
1960 * returned with siglock released.
1962 * If ptraced, this function doesn't handle stop itself. Instead,
1963 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1964 * untouched. The caller must ensure that INTERRUPT trap handling takes
1965 * places afterwards.
1968 * Must be called with @current->sighand->siglock held, which is released
1972 * %false if group stop is already cancelled or ptrace trap is scheduled.
1973 * %true if participated in group stop.
1975 static bool do_signal_stop(int signr
)
1976 __releases(¤t
->sighand
->siglock
)
1978 struct signal_struct
*sig
= current
->signal
;
1980 if (!(current
->jobctl
& JOBCTL_STOP_PENDING
)) {
1981 unsigned long gstop
= JOBCTL_STOP_PENDING
| JOBCTL_STOP_CONSUME
;
1982 struct task_struct
*t
;
1984 /* signr will be recorded in task->jobctl for retries */
1985 WARN_ON_ONCE(signr
& ~JOBCTL_STOP_SIGMASK
);
1987 if (!likely(current
->jobctl
& JOBCTL_STOP_DEQUEUED
) ||
1988 unlikely(signal_group_exit(sig
)))
1991 * There is no group stop already in progress. We must
1994 * While ptraced, a task may be resumed while group stop is
1995 * still in effect and then receive a stop signal and
1996 * initiate another group stop. This deviates from the
1997 * usual behavior as two consecutive stop signals can't
1998 * cause two group stops when !ptraced. That is why we
1999 * also check !task_is_stopped(t) below.
2001 * The condition can be distinguished by testing whether
2002 * SIGNAL_STOP_STOPPED is already set. Don't generate
2003 * group_exit_code in such case.
2005 * This is not necessary for SIGNAL_STOP_CONTINUED because
2006 * an intervening stop signal is required to cause two
2007 * continued events regardless of ptrace.
2009 if (!(sig
->flags
& SIGNAL_STOP_STOPPED
))
2010 sig
->group_exit_code
= signr
;
2012 sig
->group_stop_count
= 0;
2014 if (task_set_jobctl_pending(current
, signr
| gstop
))
2015 sig
->group_stop_count
++;
2018 while_each_thread(current
, t
) {
2020 * Setting state to TASK_STOPPED for a group
2021 * stop is always done with the siglock held,
2022 * so this check has no races.
2024 if (!task_is_stopped(t
) &&
2025 task_set_jobctl_pending(t
, signr
| gstop
)) {
2026 sig
->group_stop_count
++;
2027 if (likely(!(t
->ptrace
& PT_SEIZED
)))
2028 signal_wake_up(t
, 0);
2030 ptrace_trap_notify(t
);
2035 if (likely(!current
->ptrace
)) {
2039 * If there are no other threads in the group, or if there
2040 * is a group stop in progress and we are the last to stop,
2041 * report to the parent.
2043 if (task_participate_group_stop(current
))
2044 notify
= CLD_STOPPED
;
2046 __set_current_state(TASK_STOPPED
);
2047 spin_unlock_irq(¤t
->sighand
->siglock
);
2050 * Notify the parent of the group stop completion. Because
2051 * we're not holding either the siglock or tasklist_lock
2052 * here, ptracer may attach inbetween; however, this is for
2053 * group stop and should always be delivered to the real
2054 * parent of the group leader. The new ptracer will get
2055 * its notification when this task transitions into
2059 read_lock(&tasklist_lock
);
2060 do_notify_parent_cldstop(current
, false, notify
);
2061 read_unlock(&tasklist_lock
);
2064 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2065 freezable_schedule();
2069 * While ptraced, group stop is handled by STOP trap.
2070 * Schedule it and let the caller deal with it.
2072 task_set_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
2078 * do_jobctl_trap - take care of ptrace jobctl traps
2080 * When PT_SEIZED, it's used for both group stop and explicit
2081 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2082 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2083 * the stop signal; otherwise, %SIGTRAP.
2085 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2086 * number as exit_code and no siginfo.
2089 * Must be called with @current->sighand->siglock held, which may be
2090 * released and re-acquired before returning with intervening sleep.
2092 static void do_jobctl_trap(void)
2094 struct signal_struct
*signal
= current
->signal
;
2095 int signr
= current
->jobctl
& JOBCTL_STOP_SIGMASK
;
2097 if (current
->ptrace
& PT_SEIZED
) {
2098 if (!signal
->group_stop_count
&&
2099 !(signal
->flags
& SIGNAL_STOP_STOPPED
))
2101 WARN_ON_ONCE(!signr
);
2102 ptrace_do_notify(signr
, signr
| (PTRACE_EVENT_STOP
<< 8),
2105 WARN_ON_ONCE(!signr
);
2106 ptrace_stop(signr
, CLD_STOPPED
, 0, NULL
);
2107 current
->exit_code
= 0;
2111 static int ptrace_signal(int signr
, siginfo_t
*info
)
2114 * We do not check sig_kernel_stop(signr) but set this marker
2115 * unconditionally because we do not know whether debugger will
2116 * change signr. This flag has no meaning unless we are going
2117 * to stop after return from ptrace_stop(). In this case it will
2118 * be checked in do_signal_stop(), we should only stop if it was
2119 * not cleared by SIGCONT while we were sleeping. See also the
2120 * comment in dequeue_signal().
2122 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
2123 ptrace_stop(signr
, CLD_TRAPPED
, 0, info
);
2125 /* We're back. Did the debugger cancel the sig? */
2126 signr
= current
->exit_code
;
2130 current
->exit_code
= 0;
2133 * Update the siginfo structure if the signal has
2134 * changed. If the debugger wanted something
2135 * specific in the siginfo structure then it should
2136 * have updated *info via PTRACE_SETSIGINFO.
2138 if (signr
!= info
->si_signo
) {
2139 info
->si_signo
= signr
;
2141 info
->si_code
= SI_USER
;
2143 info
->si_pid
= task_pid_vnr(current
->parent
);
2144 info
->si_uid
= from_kuid_munged(current_user_ns(),
2145 task_uid(current
->parent
));
2149 /* If the (new) signal is now blocked, requeue it. */
2150 if (sigismember(¤t
->blocked
, signr
)) {
2151 specific_send_sig_info(signr
, info
, current
);
2158 int get_signal(struct ksignal
*ksig
)
2160 struct sighand_struct
*sighand
= current
->sighand
;
2161 struct signal_struct
*signal
= current
->signal
;
2164 if (unlikely(current
->task_works
))
2167 if (unlikely(uprobe_deny_signal()))
2171 * Do this once, we can't return to user-mode if freezing() == T.
2172 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2173 * thus do not need another check after return.
2178 spin_lock_irq(&sighand
->siglock
);
2180 * Every stopped thread goes here after wakeup. Check to see if
2181 * we should notify the parent, prepare_signal(SIGCONT) encodes
2182 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2184 if (unlikely(signal
->flags
& SIGNAL_CLD_MASK
)) {
2187 if (signal
->flags
& SIGNAL_CLD_CONTINUED
)
2188 why
= CLD_CONTINUED
;
2192 signal
->flags
&= ~SIGNAL_CLD_MASK
;
2194 spin_unlock_irq(&sighand
->siglock
);
2197 * Notify the parent that we're continuing. This event is
2198 * always per-process and doesn't make whole lot of sense
2199 * for ptracers, who shouldn't consume the state via
2200 * wait(2) either, but, for backward compatibility, notify
2201 * the ptracer of the group leader too unless it's gonna be
2204 read_lock(&tasklist_lock
);
2205 do_notify_parent_cldstop(current
, false, why
);
2207 if (ptrace_reparented(current
->group_leader
))
2208 do_notify_parent_cldstop(current
->group_leader
,
2210 read_unlock(&tasklist_lock
);
2216 struct k_sigaction
*ka
;
2218 if (unlikely(current
->jobctl
& JOBCTL_STOP_PENDING
) &&
2222 if (unlikely(current
->jobctl
& JOBCTL_TRAP_MASK
)) {
2224 spin_unlock_irq(&sighand
->siglock
);
2228 signr
= dequeue_signal(current
, ¤t
->blocked
, &ksig
->info
);
2231 break; /* will return 0 */
2233 if (unlikely(current
->ptrace
) && signr
!= SIGKILL
) {
2234 signr
= ptrace_signal(signr
, &ksig
->info
);
2239 ka
= &sighand
->action
[signr
-1];
2241 /* Trace actually delivered signals. */
2242 trace_signal_deliver(signr
, &ksig
->info
, ka
);
2244 if (ka
->sa
.sa_handler
== SIG_IGN
) /* Do nothing. */
2246 if (ka
->sa
.sa_handler
!= SIG_DFL
) {
2247 /* Run the handler. */
2250 if (ka
->sa
.sa_flags
& SA_ONESHOT
)
2251 ka
->sa
.sa_handler
= SIG_DFL
;
2253 break; /* will return non-zero "signr" value */
2257 * Now we are doing the default action for this signal.
2259 if (sig_kernel_ignore(signr
)) /* Default is nothing. */
2263 * Global init gets no signals it doesn't want.
2264 * Container-init gets no signals it doesn't want from same
2267 * Note that if global/container-init sees a sig_kernel_only()
2268 * signal here, the signal must have been generated internally
2269 * or must have come from an ancestor namespace. In either
2270 * case, the signal cannot be dropped.
2272 if (unlikely(signal
->flags
& SIGNAL_UNKILLABLE
) &&
2273 !sig_kernel_only(signr
))
2276 if (sig_kernel_stop(signr
)) {
2278 * The default action is to stop all threads in
2279 * the thread group. The job control signals
2280 * do nothing in an orphaned pgrp, but SIGSTOP
2281 * always works. Note that siglock needs to be
2282 * dropped during the call to is_orphaned_pgrp()
2283 * because of lock ordering with tasklist_lock.
2284 * This allows an intervening SIGCONT to be posted.
2285 * We need to check for that and bail out if necessary.
2287 if (signr
!= SIGSTOP
) {
2288 spin_unlock_irq(&sighand
->siglock
);
2290 /* signals can be posted during this window */
2292 if (is_current_pgrp_orphaned())
2295 spin_lock_irq(&sighand
->siglock
);
2298 if (likely(do_signal_stop(ksig
->info
.si_signo
))) {
2299 /* It released the siglock. */
2304 * We didn't actually stop, due to a race
2305 * with SIGCONT or something like that.
2310 spin_unlock_irq(&sighand
->siglock
);
2313 * Anything else is fatal, maybe with a core dump.
2315 current
->flags
|= PF_SIGNALED
;
2317 if (sig_kernel_coredump(signr
)) {
2318 if (print_fatal_signals
)
2319 print_fatal_signal(ksig
->info
.si_signo
);
2320 proc_coredump_connector(current
);
2322 * If it was able to dump core, this kills all
2323 * other threads in the group and synchronizes with
2324 * their demise. If we lost the race with another
2325 * thread getting here, it set group_exit_code
2326 * first and our do_group_exit call below will use
2327 * that value and ignore the one we pass it.
2329 do_coredump(&ksig
->info
);
2333 * Death signals, no core dump.
2335 do_group_exit(ksig
->info
.si_signo
);
2338 spin_unlock_irq(&sighand
->siglock
);
2341 return ksig
->sig
> 0;
2345 * signal_delivered -
2346 * @ksig: kernel signal struct
2347 * @stepping: nonzero if debugger single-step or block-step in use
2349 * This function should be called when a signal has successfully been
2350 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2351 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2352 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2354 static void signal_delivered(struct ksignal
*ksig
, int stepping
)
2358 /* A signal was successfully delivered, and the
2359 saved sigmask was stored on the signal frame,
2360 and will be restored by sigreturn. So we can
2361 simply clear the restore sigmask flag. */
2362 clear_restore_sigmask();
2364 sigorsets(&blocked
, ¤t
->blocked
, &ksig
->ka
.sa
.sa_mask
);
2365 if (!(ksig
->ka
.sa
.sa_flags
& SA_NODEFER
))
2366 sigaddset(&blocked
, ksig
->sig
);
2367 set_current_blocked(&blocked
);
2368 tracehook_signal_handler(stepping
);
2371 void signal_setup_done(int failed
, struct ksignal
*ksig
, int stepping
)
2374 force_sigsegv(ksig
->sig
, current
);
2376 signal_delivered(ksig
, stepping
);
2380 * It could be that complete_signal() picked us to notify about the
2381 * group-wide signal. Other threads should be notified now to take
2382 * the shared signals in @which since we will not.
2384 static void retarget_shared_pending(struct task_struct
*tsk
, sigset_t
*which
)
2387 struct task_struct
*t
;
2389 sigandsets(&retarget
, &tsk
->signal
->shared_pending
.signal
, which
);
2390 if (sigisemptyset(&retarget
))
2394 while_each_thread(tsk
, t
) {
2395 if (t
->flags
& PF_EXITING
)
2398 if (!has_pending_signals(&retarget
, &t
->blocked
))
2400 /* Remove the signals this thread can handle. */
2401 sigandsets(&retarget
, &retarget
, &t
->blocked
);
2403 if (!signal_pending(t
))
2404 signal_wake_up(t
, 0);
2406 if (sigisemptyset(&retarget
))
2411 void exit_signals(struct task_struct
*tsk
)
2417 * @tsk is about to have PF_EXITING set - lock out users which
2418 * expect stable threadgroup.
2420 cgroup_threadgroup_change_begin(tsk
);
2422 if (thread_group_empty(tsk
) || signal_group_exit(tsk
->signal
)) {
2423 tsk
->flags
|= PF_EXITING
;
2424 cgroup_threadgroup_change_end(tsk
);
2428 spin_lock_irq(&tsk
->sighand
->siglock
);
2430 * From now this task is not visible for group-wide signals,
2431 * see wants_signal(), do_signal_stop().
2433 tsk
->flags
|= PF_EXITING
;
2435 cgroup_threadgroup_change_end(tsk
);
2437 if (!signal_pending(tsk
))
2440 unblocked
= tsk
->blocked
;
2441 signotset(&unblocked
);
2442 retarget_shared_pending(tsk
, &unblocked
);
2444 if (unlikely(tsk
->jobctl
& JOBCTL_STOP_PENDING
) &&
2445 task_participate_group_stop(tsk
))
2446 group_stop
= CLD_STOPPED
;
2448 spin_unlock_irq(&tsk
->sighand
->siglock
);
2451 * If group stop has completed, deliver the notification. This
2452 * should always go to the real parent of the group leader.
2454 if (unlikely(group_stop
)) {
2455 read_lock(&tasklist_lock
);
2456 do_notify_parent_cldstop(tsk
, false, group_stop
);
2457 read_unlock(&tasklist_lock
);
2461 EXPORT_SYMBOL(recalc_sigpending
);
2462 EXPORT_SYMBOL_GPL(dequeue_signal
);
2463 EXPORT_SYMBOL(flush_signals
);
2464 EXPORT_SYMBOL(force_sig
);
2465 EXPORT_SYMBOL(send_sig
);
2466 EXPORT_SYMBOL(send_sig_info
);
2467 EXPORT_SYMBOL(sigprocmask
);
2470 * System call entry points.
2474 * sys_restart_syscall - restart a system call
2476 SYSCALL_DEFINE0(restart_syscall
)
2478 struct restart_block
*restart
= ¤t
->restart_block
;
2479 return restart
->fn(restart
);
2482 long do_no_restart_syscall(struct restart_block
*param
)
2487 static void __set_task_blocked(struct task_struct
*tsk
, const sigset_t
*newset
)
2489 if (signal_pending(tsk
) && !thread_group_empty(tsk
)) {
2490 sigset_t newblocked
;
2491 /* A set of now blocked but previously unblocked signals. */
2492 sigandnsets(&newblocked
, newset
, ¤t
->blocked
);
2493 retarget_shared_pending(tsk
, &newblocked
);
2495 tsk
->blocked
= *newset
;
2496 recalc_sigpending();
2500 * set_current_blocked - change current->blocked mask
2503 * It is wrong to change ->blocked directly, this helper should be used
2504 * to ensure the process can't miss a shared signal we are going to block.
2506 void set_current_blocked(sigset_t
*newset
)
2508 sigdelsetmask(newset
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2509 __set_current_blocked(newset
);
2512 void __set_current_blocked(const sigset_t
*newset
)
2514 struct task_struct
*tsk
= current
;
2517 * In case the signal mask hasn't changed, there is nothing we need
2518 * to do. The current->blocked shouldn't be modified by other task.
2520 if (sigequalsets(&tsk
->blocked
, newset
))
2523 spin_lock_irq(&tsk
->sighand
->siglock
);
2524 __set_task_blocked(tsk
, newset
);
2525 spin_unlock_irq(&tsk
->sighand
->siglock
);
2529 * This is also useful for kernel threads that want to temporarily
2530 * (or permanently) block certain signals.
2532 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2533 * interface happily blocks "unblockable" signals like SIGKILL
2536 int sigprocmask(int how
, sigset_t
*set
, sigset_t
*oldset
)
2538 struct task_struct
*tsk
= current
;
2541 /* Lockless, only current can change ->blocked, never from irq */
2543 *oldset
= tsk
->blocked
;
2547 sigorsets(&newset
, &tsk
->blocked
, set
);
2550 sigandnsets(&newset
, &tsk
->blocked
, set
);
2559 __set_current_blocked(&newset
);
2564 * sys_rt_sigprocmask - change the list of currently blocked signals
2565 * @how: whether to add, remove, or set signals
2566 * @nset: stores pending signals
2567 * @oset: previous value of signal mask if non-null
2568 * @sigsetsize: size of sigset_t type
2570 SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, sigset_t __user
*, nset
,
2571 sigset_t __user
*, oset
, size_t, sigsetsize
)
2573 sigset_t old_set
, new_set
;
2576 /* XXX: Don't preclude handling different sized sigset_t's. */
2577 if (sigsetsize
!= sizeof(sigset_t
))
2580 old_set
= current
->blocked
;
2583 if (copy_from_user(&new_set
, nset
, sizeof(sigset_t
)))
2585 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2587 error
= sigprocmask(how
, &new_set
, NULL
);
2593 if (copy_to_user(oset
, &old_set
, sizeof(sigset_t
)))
2600 #ifdef CONFIG_COMPAT
2601 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, compat_sigset_t __user
*, nset
,
2602 compat_sigset_t __user
*, oset
, compat_size_t
, sigsetsize
)
2605 sigset_t old_set
= current
->blocked
;
2607 /* XXX: Don't preclude handling different sized sigset_t's. */
2608 if (sigsetsize
!= sizeof(sigset_t
))
2612 compat_sigset_t new32
;
2615 if (copy_from_user(&new32
, nset
, sizeof(compat_sigset_t
)))
2618 sigset_from_compat(&new_set
, &new32
);
2619 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2621 error
= sigprocmask(how
, &new_set
, NULL
);
2626 compat_sigset_t old32
;
2627 sigset_to_compat(&old32
, &old_set
);
2628 if (copy_to_user(oset
, &old32
, sizeof(compat_sigset_t
)))
2633 return sys_rt_sigprocmask(how
, (sigset_t __user
*)nset
,
2634 (sigset_t __user
*)oset
, sigsetsize
);
2639 static int do_sigpending(void *set
, unsigned long sigsetsize
)
2641 if (sigsetsize
> sizeof(sigset_t
))
2644 spin_lock_irq(¤t
->sighand
->siglock
);
2645 sigorsets(set
, ¤t
->pending
.signal
,
2646 ¤t
->signal
->shared_pending
.signal
);
2647 spin_unlock_irq(¤t
->sighand
->siglock
);
2649 /* Outside the lock because only this thread touches it. */
2650 sigandsets(set
, ¤t
->blocked
, set
);
2655 * sys_rt_sigpending - examine a pending signal that has been raised
2657 * @uset: stores pending signals
2658 * @sigsetsize: size of sigset_t type or larger
2660 SYSCALL_DEFINE2(rt_sigpending
, sigset_t __user
*, uset
, size_t, sigsetsize
)
2663 int err
= do_sigpending(&set
, sigsetsize
);
2664 if (!err
&& copy_to_user(uset
, &set
, sigsetsize
))
2669 #ifdef CONFIG_COMPAT
2670 COMPAT_SYSCALL_DEFINE2(rt_sigpending
, compat_sigset_t __user
*, uset
,
2671 compat_size_t
, sigsetsize
)
2675 int err
= do_sigpending(&set
, sigsetsize
);
2677 compat_sigset_t set32
;
2678 sigset_to_compat(&set32
, &set
);
2679 /* we can get here only if sigsetsize <= sizeof(set) */
2680 if (copy_to_user(uset
, &set32
, sigsetsize
))
2685 return sys_rt_sigpending((sigset_t __user
*)uset
, sigsetsize
);
2690 enum siginfo_layout
siginfo_layout(int sig
, int si_code
)
2692 enum siginfo_layout layout
= SIL_KILL
;
2693 if ((si_code
> SI_USER
) && (si_code
< SI_KERNEL
)) {
2694 static const struct {
2695 unsigned char limit
, layout
;
2697 [SIGILL
] = { NSIGILL
, SIL_FAULT
},
2698 [SIGFPE
] = { NSIGFPE
, SIL_FAULT
},
2699 [SIGSEGV
] = { NSIGSEGV
, SIL_FAULT
},
2700 [SIGBUS
] = { NSIGBUS
, SIL_FAULT
},
2701 [SIGTRAP
] = { NSIGTRAP
, SIL_FAULT
},
2702 #if defined(SIGEMT) && defined(NSIGEMT)
2703 [SIGEMT
] = { NSIGEMT
, SIL_FAULT
},
2705 [SIGCHLD
] = { NSIGCHLD
, SIL_CHLD
},
2706 [SIGPOLL
] = { NSIGPOLL
, SIL_POLL
},
2707 #ifdef __ARCH_SIGSYS
2708 [SIGSYS
] = { NSIGSYS
, SIL_SYS
},
2711 if ((sig
< ARRAY_SIZE(filter
)) && (si_code
<= filter
[sig
].limit
))
2712 layout
= filter
[sig
].layout
;
2713 else if (si_code
<= NSIGPOLL
)
2716 if (si_code
== SI_TIMER
)
2718 else if (si_code
== SI_SIGIO
)
2720 else if (si_code
< 0)
2722 /* Tests to support buggy kernel ABIs */
2724 if ((sig
== SIGTRAP
) && (si_code
== TRAP_FIXME
))
2728 if ((sig
== SIGFPE
) && (si_code
== FPE_FIXME
))
2735 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2737 int copy_siginfo_to_user(siginfo_t __user
*to
, const siginfo_t
*from
)
2741 if (!access_ok (VERIFY_WRITE
, to
, sizeof(siginfo_t
)))
2743 if (from
->si_code
< 0)
2744 return __copy_to_user(to
, from
, sizeof(siginfo_t
))
2747 * If you change siginfo_t structure, please be sure
2748 * this code is fixed accordingly.
2749 * Please remember to update the signalfd_copyinfo() function
2750 * inside fs/signalfd.c too, in case siginfo_t changes.
2751 * It should never copy any pad contained in the structure
2752 * to avoid security leaks, but must copy the generic
2753 * 3 ints plus the relevant union member.
2755 err
= __put_user(from
->si_signo
, &to
->si_signo
);
2756 err
|= __put_user(from
->si_errno
, &to
->si_errno
);
2757 err
|= __put_user(from
->si_code
, &to
->si_code
);
2758 switch (siginfo_layout(from
->si_signo
, from
->si_code
)) {
2760 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2761 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2764 /* Unreached SI_TIMER is negative */
2767 err
|= __put_user(from
->si_band
, &to
->si_band
);
2768 err
|= __put_user(from
->si_fd
, &to
->si_fd
);
2771 err
|= __put_user(from
->si_addr
, &to
->si_addr
);
2772 #ifdef __ARCH_SI_TRAPNO
2773 err
|= __put_user(from
->si_trapno
, &to
->si_trapno
);
2775 #ifdef BUS_MCEERR_AO
2777 * Other callers might not initialize the si_lsb field,
2778 * so check explicitly for the right codes here.
2780 if (from
->si_signo
== SIGBUS
&&
2781 (from
->si_code
== BUS_MCEERR_AR
|| from
->si_code
== BUS_MCEERR_AO
))
2782 err
|= __put_user(from
->si_addr_lsb
, &to
->si_addr_lsb
);
2785 if (from
->si_signo
== SIGSEGV
&& from
->si_code
== SEGV_BNDERR
) {
2786 err
|= __put_user(from
->si_lower
, &to
->si_lower
);
2787 err
|= __put_user(from
->si_upper
, &to
->si_upper
);
2791 if (from
->si_signo
== SIGSEGV
&& from
->si_code
== SEGV_PKUERR
)
2792 err
|= __put_user(from
->si_pkey
, &to
->si_pkey
);
2796 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2797 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2798 err
|= __put_user(from
->si_status
, &to
->si_status
);
2799 err
|= __put_user(from
->si_utime
, &to
->si_utime
);
2800 err
|= __put_user(from
->si_stime
, &to
->si_stime
);
2803 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2804 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2805 err
|= __put_user(from
->si_ptr
, &to
->si_ptr
);
2807 #ifdef __ARCH_SIGSYS
2809 err
|= __put_user(from
->si_call_addr
, &to
->si_call_addr
);
2810 err
|= __put_user(from
->si_syscall
, &to
->si_syscall
);
2811 err
|= __put_user(from
->si_arch
, &to
->si_arch
);
2821 * do_sigtimedwait - wait for queued signals specified in @which
2822 * @which: queued signals to wait for
2823 * @info: if non-null, the signal's siginfo is returned here
2824 * @ts: upper bound on process time suspension
2826 static int do_sigtimedwait(const sigset_t
*which
, siginfo_t
*info
,
2827 const struct timespec
*ts
)
2829 ktime_t
*to
= NULL
, timeout
= KTIME_MAX
;
2830 struct task_struct
*tsk
= current
;
2831 sigset_t mask
= *which
;
2835 if (!timespec_valid(ts
))
2837 timeout
= timespec_to_ktime(*ts
);
2842 * Invert the set of allowed signals to get those we want to block.
2844 sigdelsetmask(&mask
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2847 spin_lock_irq(&tsk
->sighand
->siglock
);
2848 sig
= dequeue_signal(tsk
, &mask
, info
);
2849 if (!sig
&& timeout
) {
2851 * None ready, temporarily unblock those we're interested
2852 * while we are sleeping in so that we'll be awakened when
2853 * they arrive. Unblocking is always fine, we can avoid
2854 * set_current_blocked().
2856 tsk
->real_blocked
= tsk
->blocked
;
2857 sigandsets(&tsk
->blocked
, &tsk
->blocked
, &mask
);
2858 recalc_sigpending();
2859 spin_unlock_irq(&tsk
->sighand
->siglock
);
2861 __set_current_state(TASK_INTERRUPTIBLE
);
2862 ret
= freezable_schedule_hrtimeout_range(to
, tsk
->timer_slack_ns
,
2864 spin_lock_irq(&tsk
->sighand
->siglock
);
2865 __set_task_blocked(tsk
, &tsk
->real_blocked
);
2866 sigemptyset(&tsk
->real_blocked
);
2867 sig
= dequeue_signal(tsk
, &mask
, info
);
2869 spin_unlock_irq(&tsk
->sighand
->siglock
);
2873 return ret
? -EINTR
: -EAGAIN
;
2877 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2879 * @uthese: queued signals to wait for
2880 * @uinfo: if non-null, the signal's siginfo is returned here
2881 * @uts: upper bound on process time suspension
2882 * @sigsetsize: size of sigset_t type
2884 SYSCALL_DEFINE4(rt_sigtimedwait
, const sigset_t __user
*, uthese
,
2885 siginfo_t __user
*, uinfo
, const struct timespec __user
*, uts
,
2893 /* XXX: Don't preclude handling different sized sigset_t's. */
2894 if (sigsetsize
!= sizeof(sigset_t
))
2897 if (copy_from_user(&these
, uthese
, sizeof(these
)))
2901 if (copy_from_user(&ts
, uts
, sizeof(ts
)))
2905 ret
= do_sigtimedwait(&these
, &info
, uts
? &ts
: NULL
);
2907 if (ret
> 0 && uinfo
) {
2908 if (copy_siginfo_to_user(uinfo
, &info
))
2915 #ifdef CONFIG_COMPAT
2916 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait
, compat_sigset_t __user
*, uthese
,
2917 struct compat_siginfo __user
*, uinfo
,
2918 struct compat_timespec __user
*, uts
, compat_size_t
, sigsetsize
)
2920 compat_sigset_t s32
;
2926 if (sigsetsize
!= sizeof(sigset_t
))
2929 if (copy_from_user(&s32
, uthese
, sizeof(compat_sigset_t
)))
2931 sigset_from_compat(&s
, &s32
);
2934 if (compat_get_timespec(&t
, uts
))
2938 ret
= do_sigtimedwait(&s
, &info
, uts
? &t
: NULL
);
2940 if (ret
> 0 && uinfo
) {
2941 if (copy_siginfo_to_user32(uinfo
, &info
))
2950 * sys_kill - send a signal to a process
2951 * @pid: the PID of the process
2952 * @sig: signal to be sent
2954 SYSCALL_DEFINE2(kill
, pid_t
, pid
, int, sig
)
2956 struct siginfo info
;
2958 info
.si_signo
= sig
;
2960 info
.si_code
= SI_USER
;
2961 info
.si_pid
= task_tgid_vnr(current
);
2962 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
2964 return kill_something_info(sig
, &info
, pid
);
2968 do_send_specific(pid_t tgid
, pid_t pid
, int sig
, struct siginfo
*info
)
2970 struct task_struct
*p
;
2974 p
= find_task_by_vpid(pid
);
2975 if (p
&& (tgid
<= 0 || task_tgid_vnr(p
) == tgid
)) {
2976 error
= check_kill_permission(sig
, info
, p
);
2978 * The null signal is a permissions and process existence
2979 * probe. No signal is actually delivered.
2981 if (!error
&& sig
) {
2982 error
= do_send_sig_info(sig
, info
, p
, false);
2984 * If lock_task_sighand() failed we pretend the task
2985 * dies after receiving the signal. The window is tiny,
2986 * and the signal is private anyway.
2988 if (unlikely(error
== -ESRCH
))
2997 static int do_tkill(pid_t tgid
, pid_t pid
, int sig
)
2999 struct siginfo info
= {};
3001 info
.si_signo
= sig
;
3003 info
.si_code
= SI_TKILL
;
3004 info
.si_pid
= task_tgid_vnr(current
);
3005 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
3007 return do_send_specific(tgid
, pid
, sig
, &info
);
3011 * sys_tgkill - send signal to one specific thread
3012 * @tgid: the thread group ID of the thread
3013 * @pid: the PID of the thread
3014 * @sig: signal to be sent
3016 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3017 * exists but it's not belonging to the target process anymore. This
3018 * method solves the problem of threads exiting and PIDs getting reused.
3020 SYSCALL_DEFINE3(tgkill
, pid_t
, tgid
, pid_t
, pid
, int, sig
)
3022 /* This is only valid for single tasks */
3023 if (pid
<= 0 || tgid
<= 0)
3026 return do_tkill(tgid
, pid
, sig
);
3030 * sys_tkill - send signal to one specific task
3031 * @pid: the PID of the task
3032 * @sig: signal to be sent
3034 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3036 SYSCALL_DEFINE2(tkill
, pid_t
, pid
, int, sig
)
3038 /* This is only valid for single tasks */
3042 return do_tkill(0, pid
, sig
);
3045 static int do_rt_sigqueueinfo(pid_t pid
, int sig
, siginfo_t
*info
)
3047 /* Not even root can pretend to send signals from the kernel.
3048 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3050 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
3051 (task_pid_vnr(current
) != pid
))
3054 info
->si_signo
= sig
;
3056 /* POSIX.1b doesn't mention process groups. */
3057 return kill_proc_info(sig
, info
, pid
);
3061 * sys_rt_sigqueueinfo - send signal information to a signal
3062 * @pid: the PID of the thread
3063 * @sig: signal to be sent
3064 * @uinfo: signal info to be sent
3066 SYSCALL_DEFINE3(rt_sigqueueinfo
, pid_t
, pid
, int, sig
,
3067 siginfo_t __user
*, uinfo
)
3070 if (copy_from_user(&info
, uinfo
, sizeof(siginfo_t
)))
3072 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3075 #ifdef CONFIG_COMPAT
3076 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo
,
3079 struct compat_siginfo __user
*, uinfo
)
3081 siginfo_t info
= {};
3082 int ret
= copy_siginfo_from_user32(&info
, uinfo
);
3085 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3089 static int do_rt_tgsigqueueinfo(pid_t tgid
, pid_t pid
, int sig
, siginfo_t
*info
)
3091 /* This is only valid for single tasks */
3092 if (pid
<= 0 || tgid
<= 0)
3095 /* Not even root can pretend to send signals from the kernel.
3096 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3098 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
3099 (task_pid_vnr(current
) != pid
))
3102 info
->si_signo
= sig
;
3104 return do_send_specific(tgid
, pid
, sig
, info
);
3107 SYSCALL_DEFINE4(rt_tgsigqueueinfo
, pid_t
, tgid
, pid_t
, pid
, int, sig
,
3108 siginfo_t __user
*, uinfo
)
3112 if (copy_from_user(&info
, uinfo
, sizeof(siginfo_t
)))
3115 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3118 #ifdef CONFIG_COMPAT
3119 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo
,
3123 struct compat_siginfo __user
*, uinfo
)
3125 siginfo_t info
= {};
3127 if (copy_siginfo_from_user32(&info
, uinfo
))
3129 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3134 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3136 void kernel_sigaction(int sig
, __sighandler_t action
)
3138 spin_lock_irq(¤t
->sighand
->siglock
);
3139 current
->sighand
->action
[sig
- 1].sa
.sa_handler
= action
;
3140 if (action
== SIG_IGN
) {
3144 sigaddset(&mask
, sig
);
3146 flush_sigqueue_mask(&mask
, ¤t
->signal
->shared_pending
);
3147 flush_sigqueue_mask(&mask
, ¤t
->pending
);
3148 recalc_sigpending();
3150 spin_unlock_irq(¤t
->sighand
->siglock
);
3152 EXPORT_SYMBOL(kernel_sigaction
);
3154 void __weak
sigaction_compat_abi(struct k_sigaction
*act
,
3155 struct k_sigaction
*oact
)
3159 int do_sigaction(int sig
, struct k_sigaction
*act
, struct k_sigaction
*oact
)
3161 struct task_struct
*p
= current
, *t
;
3162 struct k_sigaction
*k
;
3165 if (!valid_signal(sig
) || sig
< 1 || (act
&& sig_kernel_only(sig
)))
3168 k
= &p
->sighand
->action
[sig
-1];
3170 spin_lock_irq(&p
->sighand
->siglock
);
3174 sigaction_compat_abi(act
, oact
);
3177 sigdelsetmask(&act
->sa
.sa_mask
,
3178 sigmask(SIGKILL
) | sigmask(SIGSTOP
));
3182 * "Setting a signal action to SIG_IGN for a signal that is
3183 * pending shall cause the pending signal to be discarded,
3184 * whether or not it is blocked."
3186 * "Setting a signal action to SIG_DFL for a signal that is
3187 * pending and whose default action is to ignore the signal
3188 * (for example, SIGCHLD), shall cause the pending signal to
3189 * be discarded, whether or not it is blocked"
3191 if (sig_handler_ignored(sig_handler(p
, sig
), sig
)) {
3193 sigaddset(&mask
, sig
);
3194 flush_sigqueue_mask(&mask
, &p
->signal
->shared_pending
);
3195 for_each_thread(p
, t
)
3196 flush_sigqueue_mask(&mask
, &t
->pending
);
3200 spin_unlock_irq(&p
->sighand
->siglock
);
3205 do_sigaltstack (const stack_t
*ss
, stack_t
*oss
, unsigned long sp
)
3207 struct task_struct
*t
= current
;
3210 memset(oss
, 0, sizeof(stack_t
));
3211 oss
->ss_sp
= (void __user
*) t
->sas_ss_sp
;
3212 oss
->ss_size
= t
->sas_ss_size
;
3213 oss
->ss_flags
= sas_ss_flags(sp
) |
3214 (current
->sas_ss_flags
& SS_FLAG_BITS
);
3218 void __user
*ss_sp
= ss
->ss_sp
;
3219 size_t ss_size
= ss
->ss_size
;
3220 unsigned ss_flags
= ss
->ss_flags
;
3223 if (unlikely(on_sig_stack(sp
)))
3226 ss_mode
= ss_flags
& ~SS_FLAG_BITS
;
3227 if (unlikely(ss_mode
!= SS_DISABLE
&& ss_mode
!= SS_ONSTACK
&&
3231 if (ss_mode
== SS_DISABLE
) {
3235 if (unlikely(ss_size
< MINSIGSTKSZ
))
3239 t
->sas_ss_sp
= (unsigned long) ss_sp
;
3240 t
->sas_ss_size
= ss_size
;
3241 t
->sas_ss_flags
= ss_flags
;
3246 SYSCALL_DEFINE2(sigaltstack
,const stack_t __user
*,uss
, stack_t __user
*,uoss
)
3250 if (uss
&& copy_from_user(&new, uss
, sizeof(stack_t
)))
3252 err
= do_sigaltstack(uss
? &new : NULL
, uoss
? &old
: NULL
,
3253 current_user_stack_pointer());
3254 if (!err
&& uoss
&& copy_to_user(uoss
, &old
, sizeof(stack_t
)))
3259 int restore_altstack(const stack_t __user
*uss
)
3262 if (copy_from_user(&new, uss
, sizeof(stack_t
)))
3264 (void)do_sigaltstack(&new, NULL
, current_user_stack_pointer());
3265 /* squash all but EFAULT for now */
3269 int __save_altstack(stack_t __user
*uss
, unsigned long sp
)
3271 struct task_struct
*t
= current
;
3272 int err
= __put_user((void __user
*)t
->sas_ss_sp
, &uss
->ss_sp
) |
3273 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
3274 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
3277 if (t
->sas_ss_flags
& SS_AUTODISARM
)
3282 #ifdef CONFIG_COMPAT
3283 COMPAT_SYSCALL_DEFINE2(sigaltstack
,
3284 const compat_stack_t __user
*, uss_ptr
,
3285 compat_stack_t __user
*, uoss_ptr
)
3291 compat_stack_t uss32
;
3292 if (copy_from_user(&uss32
, uss_ptr
, sizeof(compat_stack_t
)))
3294 uss
.ss_sp
= compat_ptr(uss32
.ss_sp
);
3295 uss
.ss_flags
= uss32
.ss_flags
;
3296 uss
.ss_size
= uss32
.ss_size
;
3298 ret
= do_sigaltstack(uss_ptr
? &uss
: NULL
, &uoss
,
3299 compat_user_stack_pointer());
3300 if (ret
>= 0 && uoss_ptr
) {
3302 memset(&old
, 0, sizeof(old
));
3303 old
.ss_sp
= ptr_to_compat(uoss
.ss_sp
);
3304 old
.ss_flags
= uoss
.ss_flags
;
3305 old
.ss_size
= uoss
.ss_size
;
3306 if (copy_to_user(uoss_ptr
, &old
, sizeof(compat_stack_t
)))
3312 int compat_restore_altstack(const compat_stack_t __user
*uss
)
3314 int err
= compat_sys_sigaltstack(uss
, NULL
);
3315 /* squash all but -EFAULT for now */
3316 return err
== -EFAULT
? err
: 0;
3319 int __compat_save_altstack(compat_stack_t __user
*uss
, unsigned long sp
)
3322 struct task_struct
*t
= current
;
3323 err
= __put_user(ptr_to_compat((void __user
*)t
->sas_ss_sp
),
3325 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
3326 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
3329 if (t
->sas_ss_flags
& SS_AUTODISARM
)
3335 #ifdef __ARCH_WANT_SYS_SIGPENDING
3338 * sys_sigpending - examine pending signals
3339 * @set: where mask of pending signal is returned
3341 SYSCALL_DEFINE1(sigpending
, old_sigset_t __user
*, set
)
3343 return sys_rt_sigpending((sigset_t __user
*)set
, sizeof(old_sigset_t
));
3346 #ifdef CONFIG_COMPAT
3347 COMPAT_SYSCALL_DEFINE1(sigpending
, compat_old_sigset_t __user
*, set32
)
3351 int err
= do_sigpending(&set
, sizeof(set
.sig
[0]));
3353 err
= put_user(set
.sig
[0], set32
);
3356 return sys_rt_sigpending((sigset_t __user
*)set32
, sizeof(*set32
));
3363 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3365 * sys_sigprocmask - examine and change blocked signals
3366 * @how: whether to add, remove, or set signals
3367 * @nset: signals to add or remove (if non-null)
3368 * @oset: previous value of signal mask if non-null
3370 * Some platforms have their own version with special arguments;
3371 * others support only sys_rt_sigprocmask.
3374 SYSCALL_DEFINE3(sigprocmask
, int, how
, old_sigset_t __user
*, nset
,
3375 old_sigset_t __user
*, oset
)
3377 old_sigset_t old_set
, new_set
;
3378 sigset_t new_blocked
;
3380 old_set
= current
->blocked
.sig
[0];
3383 if (copy_from_user(&new_set
, nset
, sizeof(*nset
)))
3386 new_blocked
= current
->blocked
;
3390 sigaddsetmask(&new_blocked
, new_set
);
3393 sigdelsetmask(&new_blocked
, new_set
);
3396 new_blocked
.sig
[0] = new_set
;
3402 set_current_blocked(&new_blocked
);
3406 if (copy_to_user(oset
, &old_set
, sizeof(*oset
)))
3412 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3414 #ifndef CONFIG_ODD_RT_SIGACTION
3416 * sys_rt_sigaction - alter an action taken by a process
3417 * @sig: signal to be sent
3418 * @act: new sigaction
3419 * @oact: used to save the previous sigaction
3420 * @sigsetsize: size of sigset_t type
3422 SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
3423 const struct sigaction __user
*, act
,
3424 struct sigaction __user
*, oact
,
3427 struct k_sigaction new_sa
, old_sa
;
3430 /* XXX: Don't preclude handling different sized sigset_t's. */
3431 if (sigsetsize
!= sizeof(sigset_t
))
3435 if (copy_from_user(&new_sa
.sa
, act
, sizeof(new_sa
.sa
)))
3439 ret
= do_sigaction(sig
, act
? &new_sa
: NULL
, oact
? &old_sa
: NULL
);
3442 if (copy_to_user(oact
, &old_sa
.sa
, sizeof(old_sa
.sa
)))
3448 #ifdef CONFIG_COMPAT
3449 COMPAT_SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
3450 const struct compat_sigaction __user
*, act
,
3451 struct compat_sigaction __user
*, oact
,
3452 compat_size_t
, sigsetsize
)
3454 struct k_sigaction new_ka
, old_ka
;
3455 compat_sigset_t mask
;
3456 #ifdef __ARCH_HAS_SA_RESTORER
3457 compat_uptr_t restorer
;
3461 /* XXX: Don't preclude handling different sized sigset_t's. */
3462 if (sigsetsize
!= sizeof(compat_sigset_t
))
3466 compat_uptr_t handler
;
3467 ret
= get_user(handler
, &act
->sa_handler
);
3468 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
3469 #ifdef __ARCH_HAS_SA_RESTORER
3470 ret
|= get_user(restorer
, &act
->sa_restorer
);
3471 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
3473 ret
|= copy_from_user(&mask
, &act
->sa_mask
, sizeof(mask
));
3474 ret
|= get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
);
3477 sigset_from_compat(&new_ka
.sa
.sa_mask
, &mask
);
3480 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3482 sigset_to_compat(&mask
, &old_ka
.sa
.sa_mask
);
3483 ret
= put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
3485 ret
|= copy_to_user(&oact
->sa_mask
, &mask
, sizeof(mask
));
3486 ret
|= put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
);
3487 #ifdef __ARCH_HAS_SA_RESTORER
3488 ret
|= put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
3489 &oact
->sa_restorer
);
3495 #endif /* !CONFIG_ODD_RT_SIGACTION */
3497 #ifdef CONFIG_OLD_SIGACTION
3498 SYSCALL_DEFINE3(sigaction
, int, sig
,
3499 const struct old_sigaction __user
*, act
,
3500 struct old_sigaction __user
*, oact
)
3502 struct k_sigaction new_ka
, old_ka
;
3507 if (!access_ok(VERIFY_READ
, act
, sizeof(*act
)) ||
3508 __get_user(new_ka
.sa
.sa_handler
, &act
->sa_handler
) ||
3509 __get_user(new_ka
.sa
.sa_restorer
, &act
->sa_restorer
) ||
3510 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
3511 __get_user(mask
, &act
->sa_mask
))
3513 #ifdef __ARCH_HAS_KA_RESTORER
3514 new_ka
.ka_restorer
= NULL
;
3516 siginitset(&new_ka
.sa
.sa_mask
, mask
);
3519 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3522 if (!access_ok(VERIFY_WRITE
, oact
, sizeof(*oact
)) ||
3523 __put_user(old_ka
.sa
.sa_handler
, &oact
->sa_handler
) ||
3524 __put_user(old_ka
.sa
.sa_restorer
, &oact
->sa_restorer
) ||
3525 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
3526 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
3533 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3534 COMPAT_SYSCALL_DEFINE3(sigaction
, int, sig
,
3535 const struct compat_old_sigaction __user
*, act
,
3536 struct compat_old_sigaction __user
*, oact
)
3538 struct k_sigaction new_ka
, old_ka
;
3540 compat_old_sigset_t mask
;
3541 compat_uptr_t handler
, restorer
;
3544 if (!access_ok(VERIFY_READ
, act
, sizeof(*act
)) ||
3545 __get_user(handler
, &act
->sa_handler
) ||
3546 __get_user(restorer
, &act
->sa_restorer
) ||
3547 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
3548 __get_user(mask
, &act
->sa_mask
))
3551 #ifdef __ARCH_HAS_KA_RESTORER
3552 new_ka
.ka_restorer
= NULL
;
3554 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
3555 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
3556 siginitset(&new_ka
.sa
.sa_mask
, mask
);
3559 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3562 if (!access_ok(VERIFY_WRITE
, oact
, sizeof(*oact
)) ||
3563 __put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
3564 &oact
->sa_handler
) ||
3565 __put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
3566 &oact
->sa_restorer
) ||
3567 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
3568 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
3575 #ifdef CONFIG_SGETMASK_SYSCALL
3578 * For backwards compatibility. Functionality superseded by sigprocmask.
3580 SYSCALL_DEFINE0(sgetmask
)
3583 return current
->blocked
.sig
[0];
3586 SYSCALL_DEFINE1(ssetmask
, int, newmask
)
3588 int old
= current
->blocked
.sig
[0];
3591 siginitset(&newset
, newmask
);
3592 set_current_blocked(&newset
);
3596 #endif /* CONFIG_SGETMASK_SYSCALL */
3598 #ifdef __ARCH_WANT_SYS_SIGNAL
3600 * For backwards compatibility. Functionality superseded by sigaction.
3602 SYSCALL_DEFINE2(signal
, int, sig
, __sighandler_t
, handler
)
3604 struct k_sigaction new_sa
, old_sa
;
3607 new_sa
.sa
.sa_handler
= handler
;
3608 new_sa
.sa
.sa_flags
= SA_ONESHOT
| SA_NOMASK
;
3609 sigemptyset(&new_sa
.sa
.sa_mask
);
3611 ret
= do_sigaction(sig
, &new_sa
, &old_sa
);
3613 return ret
? ret
: (unsigned long)old_sa
.sa
.sa_handler
;
3615 #endif /* __ARCH_WANT_SYS_SIGNAL */
3617 #ifdef __ARCH_WANT_SYS_PAUSE
3619 SYSCALL_DEFINE0(pause
)
3621 while (!signal_pending(current
)) {
3622 __set_current_state(TASK_INTERRUPTIBLE
);
3625 return -ERESTARTNOHAND
;
3630 static int sigsuspend(sigset_t
*set
)
3632 current
->saved_sigmask
= current
->blocked
;
3633 set_current_blocked(set
);
3635 while (!signal_pending(current
)) {
3636 __set_current_state(TASK_INTERRUPTIBLE
);
3639 set_restore_sigmask();
3640 return -ERESTARTNOHAND
;
3644 * sys_rt_sigsuspend - replace the signal mask for a value with the
3645 * @unewset value until a signal is received
3646 * @unewset: new signal mask value
3647 * @sigsetsize: size of sigset_t type
3649 SYSCALL_DEFINE2(rt_sigsuspend
, sigset_t __user
*, unewset
, size_t, sigsetsize
)
3653 /* XXX: Don't preclude handling different sized sigset_t's. */
3654 if (sigsetsize
!= sizeof(sigset_t
))
3657 if (copy_from_user(&newset
, unewset
, sizeof(newset
)))
3659 return sigsuspend(&newset
);
3662 #ifdef CONFIG_COMPAT
3663 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend
, compat_sigset_t __user
*, unewset
, compat_size_t
, sigsetsize
)
3667 compat_sigset_t newset32
;
3669 /* XXX: Don't preclude handling different sized sigset_t's. */
3670 if (sigsetsize
!= sizeof(sigset_t
))
3673 if (copy_from_user(&newset32
, unewset
, sizeof(compat_sigset_t
)))
3675 sigset_from_compat(&newset
, &newset32
);
3676 return sigsuspend(&newset
);
3678 /* on little-endian bitmaps don't care about granularity */
3679 return sys_rt_sigsuspend((sigset_t __user
*)unewset
, sigsetsize
);
3684 #ifdef CONFIG_OLD_SIGSUSPEND
3685 SYSCALL_DEFINE1(sigsuspend
, old_sigset_t
, mask
)
3688 siginitset(&blocked
, mask
);
3689 return sigsuspend(&blocked
);
3692 #ifdef CONFIG_OLD_SIGSUSPEND3
3693 SYSCALL_DEFINE3(sigsuspend
, int, unused1
, int, unused2
, old_sigset_t
, mask
)
3696 siginitset(&blocked
, mask
);
3697 return sigsuspend(&blocked
);
3701 __weak
const char *arch_vma_name(struct vm_area_struct
*vma
)
3706 void __init
signals_init(void)
3708 /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */
3709 BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE
3710 != offsetof(struct siginfo
, _sifields
._pad
));
3712 sigqueue_cachep
= KMEM_CACHE(sigqueue
, SLAB_PANIC
);
3715 #ifdef CONFIG_KGDB_KDB
3716 #include <linux/kdb.h>
3718 * kdb_send_sig_info - Allows kdb to send signals without exposing
3719 * signal internals. This function checks if the required locks are
3720 * available before calling the main signal code, to avoid kdb
3724 kdb_send_sig_info(struct task_struct
*t
, struct siginfo
*info
)
3726 static struct task_struct
*kdb_prev_t
;
3728 if (!spin_trylock(&t
->sighand
->siglock
)) {
3729 kdb_printf("Can't do kill command now.\n"
3730 "The sigmask lock is held somewhere else in "
3731 "kernel, try again later\n");
3734 spin_unlock(&t
->sighand
->siglock
);
3735 new_t
= kdb_prev_t
!= t
;
3737 if (t
->state
!= TASK_RUNNING
&& new_t
) {
3738 kdb_printf("Process is not RUNNING, sending a signal from "
3739 "kdb risks deadlock\n"
3740 "on the run queue locks. "
3741 "The signal has _not_ been sent.\n"
3742 "Reissue the kill command if you want to risk "
3746 sig
= info
->si_signo
;
3747 if (send_sig_info(sig
, info
, t
))
3748 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3751 kdb_printf("Signal %d is sent to process %d.\n", sig
, t
->pid
);
3753 #endif /* CONFIG_KGDB_KDB */