2 * linux/kernel/signal.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
8 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
9 * Changes to use preallocated sigqueue structures
10 * to allow signals to be sent reliably.
13 #include <linux/slab.h>
14 #include <linux/export.h>
15 #include <linux/init.h>
16 #include <linux/sched.h>
18 #include <linux/tty.h>
19 #include <linux/binfmts.h>
20 #include <linux/coredump.h>
21 #include <linux/security.h>
22 #include <linux/syscalls.h>
23 #include <linux/ptrace.h>
24 #include <linux/signal.h>
25 #include <linux/signalfd.h>
26 #include <linux/ratelimit.h>
27 #include <linux/tracehook.h>
28 #include <linux/capability.h>
29 #include <linux/freezer.h>
30 #include <linux/pid_namespace.h>
31 #include <linux/nsproxy.h>
32 #include <linux/user_namespace.h>
33 #include <linux/uprobes.h>
34 #include <linux/compat.h>
35 #include <linux/cn_proc.h>
36 #include <linux/compiler.h>
38 #define CREATE_TRACE_POINTS
39 #include <trace/events/signal.h>
41 #include <asm/param.h>
42 #include <asm/uaccess.h>
43 #include <asm/unistd.h>
44 #include <asm/siginfo.h>
45 #include <asm/cacheflush.h>
46 #include "audit.h" /* audit_signal_info() */
49 * SLAB caches for signal bits.
52 static struct kmem_cache
*sigqueue_cachep
;
54 int print_fatal_signals __read_mostly
;
56 static void __user
*sig_handler(struct task_struct
*t
, int sig
)
58 return t
->sighand
->action
[sig
- 1].sa
.sa_handler
;
61 static int sig_handler_ignored(void __user
*handler
, int sig
)
63 /* Is it explicitly or implicitly ignored? */
64 return handler
== SIG_IGN
||
65 (handler
== SIG_DFL
&& sig_kernel_ignore(sig
));
68 static int sig_task_ignored(struct task_struct
*t
, int sig
, bool force
)
72 handler
= sig_handler(t
, sig
);
74 if (unlikely(t
->signal
->flags
& SIGNAL_UNKILLABLE
) &&
75 handler
== SIG_DFL
&& !force
)
78 return sig_handler_ignored(handler
, sig
);
81 static int sig_ignored(struct task_struct
*t
, int sig
, bool force
)
84 * Blocked signals are never ignored, since the
85 * signal handler may change by the time it is
88 if (sigismember(&t
->blocked
, sig
) || sigismember(&t
->real_blocked
, sig
))
91 if (!sig_task_ignored(t
, sig
, force
))
95 * Tracers may want to know about even ignored signals.
101 * Re-calculate pending state from the set of locally pending
102 * signals, globally pending signals, and blocked signals.
104 static inline int has_pending_signals(sigset_t
*signal
, sigset_t
*blocked
)
109 switch (_NSIG_WORDS
) {
111 for (i
= _NSIG_WORDS
, ready
= 0; --i
>= 0 ;)
112 ready
|= signal
->sig
[i
] &~ blocked
->sig
[i
];
115 case 4: ready
= signal
->sig
[3] &~ blocked
->sig
[3];
116 ready
|= signal
->sig
[2] &~ blocked
->sig
[2];
117 ready
|= signal
->sig
[1] &~ blocked
->sig
[1];
118 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
121 case 2: ready
= signal
->sig
[1] &~ blocked
->sig
[1];
122 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
125 case 1: ready
= signal
->sig
[0] &~ blocked
->sig
[0];
130 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
132 static int recalc_sigpending_tsk(struct task_struct
*t
)
134 if ((t
->jobctl
& JOBCTL_PENDING_MASK
) ||
135 PENDING(&t
->pending
, &t
->blocked
) ||
136 PENDING(&t
->signal
->shared_pending
, &t
->blocked
)) {
137 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
141 * We must never clear the flag in another thread, or in current
142 * when it's possible the current syscall is returning -ERESTART*.
143 * So we don't clear it here, and only callers who know they should do.
149 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
150 * This is superfluous when called on current, the wakeup is a harmless no-op.
152 void recalc_sigpending_and_wake(struct task_struct
*t
)
154 if (recalc_sigpending_tsk(t
))
155 signal_wake_up(t
, 0);
158 void recalc_sigpending(void)
160 if (!recalc_sigpending_tsk(current
) && !freezing(current
))
161 clear_thread_flag(TIF_SIGPENDING
);
165 /* Given the mask, find the first available signal that should be serviced. */
167 #define SYNCHRONOUS_MASK \
168 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
169 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
171 int next_signal(struct sigpending
*pending
, sigset_t
*mask
)
173 unsigned long i
, *s
, *m
, x
;
176 s
= pending
->signal
.sig
;
180 * Handle the first word specially: it contains the
181 * synchronous signals that need to be dequeued first.
185 if (x
& SYNCHRONOUS_MASK
)
186 x
&= SYNCHRONOUS_MASK
;
191 switch (_NSIG_WORDS
) {
193 for (i
= 1; i
< _NSIG_WORDS
; ++i
) {
197 sig
= ffz(~x
) + i
*_NSIG_BPW
+ 1;
206 sig
= ffz(~x
) + _NSIG_BPW
+ 1;
217 static inline void print_dropped_signal(int sig
)
219 static DEFINE_RATELIMIT_STATE(ratelimit_state
, 5 * HZ
, 10);
221 if (!print_fatal_signals
)
224 if (!__ratelimit(&ratelimit_state
))
227 printk(KERN_INFO
"%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
228 current
->comm
, current
->pid
, sig
);
232 * task_set_jobctl_pending - set jobctl pending bits
234 * @mask: pending bits to set
236 * Clear @mask from @task->jobctl. @mask must be subset of
237 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
238 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
239 * cleared. If @task is already being killed or exiting, this function
243 * Must be called with @task->sighand->siglock held.
246 * %true if @mask is set, %false if made noop because @task was dying.
248 bool task_set_jobctl_pending(struct task_struct
*task
, unsigned int mask
)
250 BUG_ON(mask
& ~(JOBCTL_PENDING_MASK
| JOBCTL_STOP_CONSUME
|
251 JOBCTL_STOP_SIGMASK
| JOBCTL_TRAPPING
));
252 BUG_ON((mask
& JOBCTL_TRAPPING
) && !(mask
& JOBCTL_PENDING_MASK
));
254 if (unlikely(fatal_signal_pending(task
) || (task
->flags
& PF_EXITING
)))
257 if (mask
& JOBCTL_STOP_SIGMASK
)
258 task
->jobctl
&= ~JOBCTL_STOP_SIGMASK
;
260 task
->jobctl
|= mask
;
265 * task_clear_jobctl_trapping - clear jobctl trapping bit
268 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
269 * Clear it and wake up the ptracer. Note that we don't need any further
270 * locking. @task->siglock guarantees that @task->parent points to the
274 * Must be called with @task->sighand->siglock held.
276 void task_clear_jobctl_trapping(struct task_struct
*task
)
278 if (unlikely(task
->jobctl
& JOBCTL_TRAPPING
)) {
279 task
->jobctl
&= ~JOBCTL_TRAPPING
;
280 smp_mb(); /* advised by wake_up_bit() */
281 wake_up_bit(&task
->jobctl
, JOBCTL_TRAPPING_BIT
);
286 * task_clear_jobctl_pending - clear jobctl pending bits
288 * @mask: pending bits to clear
290 * Clear @mask from @task->jobctl. @mask must be subset of
291 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
292 * STOP bits are cleared together.
294 * If clearing of @mask leaves no stop or trap pending, this function calls
295 * task_clear_jobctl_trapping().
298 * Must be called with @task->sighand->siglock held.
300 void task_clear_jobctl_pending(struct task_struct
*task
, unsigned int mask
)
302 BUG_ON(mask
& ~JOBCTL_PENDING_MASK
);
304 if (mask
& JOBCTL_STOP_PENDING
)
305 mask
|= JOBCTL_STOP_CONSUME
| JOBCTL_STOP_DEQUEUED
;
307 task
->jobctl
&= ~mask
;
309 if (!(task
->jobctl
& JOBCTL_PENDING_MASK
))
310 task_clear_jobctl_trapping(task
);
314 * task_participate_group_stop - participate in a group stop
315 * @task: task participating in a group stop
317 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
318 * Group stop states are cleared and the group stop count is consumed if
319 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
320 * stop, the appropriate %SIGNAL_* flags are set.
323 * Must be called with @task->sighand->siglock held.
326 * %true if group stop completion should be notified to the parent, %false
329 static bool task_participate_group_stop(struct task_struct
*task
)
331 struct signal_struct
*sig
= task
->signal
;
332 bool consume
= task
->jobctl
& JOBCTL_STOP_CONSUME
;
334 WARN_ON_ONCE(!(task
->jobctl
& JOBCTL_STOP_PENDING
));
336 task_clear_jobctl_pending(task
, JOBCTL_STOP_PENDING
);
341 if (!WARN_ON_ONCE(sig
->group_stop_count
== 0))
342 sig
->group_stop_count
--;
345 * Tell the caller to notify completion iff we are entering into a
346 * fresh group stop. Read comment in do_signal_stop() for details.
348 if (!sig
->group_stop_count
&& !(sig
->flags
& SIGNAL_STOP_STOPPED
)) {
349 sig
->flags
= SIGNAL_STOP_STOPPED
;
356 * allocate a new signal queue record
357 * - this may be called without locks if and only if t == current, otherwise an
358 * appropriate lock must be held to stop the target task from exiting
360 static struct sigqueue
*
361 __sigqueue_alloc(int sig
, struct task_struct
*t
, gfp_t flags
, int override_rlimit
)
363 struct sigqueue
*q
= NULL
;
364 struct user_struct
*user
;
367 * Protect access to @t credentials. This can go away when all
368 * callers hold rcu read lock.
371 user
= get_uid(__task_cred(t
)->user
);
372 atomic_inc(&user
->sigpending
);
375 if (override_rlimit
||
376 atomic_read(&user
->sigpending
) <=
377 task_rlimit(t
, RLIMIT_SIGPENDING
)) {
378 q
= kmem_cache_alloc(sigqueue_cachep
, flags
);
380 print_dropped_signal(sig
);
383 if (unlikely(q
== NULL
)) {
384 atomic_dec(&user
->sigpending
);
387 INIT_LIST_HEAD(&q
->list
);
395 static void __sigqueue_free(struct sigqueue
*q
)
397 if (q
->flags
& SIGQUEUE_PREALLOC
)
399 atomic_dec(&q
->user
->sigpending
);
401 kmem_cache_free(sigqueue_cachep
, q
);
404 void flush_sigqueue(struct sigpending
*queue
)
408 sigemptyset(&queue
->signal
);
409 while (!list_empty(&queue
->list
)) {
410 q
= list_entry(queue
->list
.next
, struct sigqueue
, list
);
411 list_del_init(&q
->list
);
417 * Flush all pending signals for a task.
419 void __flush_signals(struct task_struct
*t
)
421 clear_tsk_thread_flag(t
, TIF_SIGPENDING
);
422 flush_sigqueue(&t
->pending
);
423 flush_sigqueue(&t
->signal
->shared_pending
);
426 void flush_signals(struct task_struct
*t
)
430 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
432 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
435 static void __flush_itimer_signals(struct sigpending
*pending
)
437 sigset_t signal
, retain
;
438 struct sigqueue
*q
, *n
;
440 signal
= pending
->signal
;
441 sigemptyset(&retain
);
443 list_for_each_entry_safe(q
, n
, &pending
->list
, list
) {
444 int sig
= q
->info
.si_signo
;
446 if (likely(q
->info
.si_code
!= SI_TIMER
)) {
447 sigaddset(&retain
, sig
);
449 sigdelset(&signal
, sig
);
450 list_del_init(&q
->list
);
455 sigorsets(&pending
->signal
, &signal
, &retain
);
458 void flush_itimer_signals(void)
460 struct task_struct
*tsk
= current
;
463 spin_lock_irqsave(&tsk
->sighand
->siglock
, flags
);
464 __flush_itimer_signals(&tsk
->pending
);
465 __flush_itimer_signals(&tsk
->signal
->shared_pending
);
466 spin_unlock_irqrestore(&tsk
->sighand
->siglock
, flags
);
469 void ignore_signals(struct task_struct
*t
)
473 for (i
= 0; i
< _NSIG
; ++i
)
474 t
->sighand
->action
[i
].sa
.sa_handler
= SIG_IGN
;
480 * Flush all handlers for a task.
484 flush_signal_handlers(struct task_struct
*t
, int force_default
)
487 struct k_sigaction
*ka
= &t
->sighand
->action
[0];
488 for (i
= _NSIG
; i
!= 0 ; i
--) {
489 if (force_default
|| ka
->sa
.sa_handler
!= SIG_IGN
)
490 ka
->sa
.sa_handler
= SIG_DFL
;
492 #ifdef __ARCH_HAS_SA_RESTORER
493 ka
->sa
.sa_restorer
= NULL
;
495 sigemptyset(&ka
->sa
.sa_mask
);
500 int unhandled_signal(struct task_struct
*tsk
, int sig
)
502 void __user
*handler
= tsk
->sighand
->action
[sig
-1].sa
.sa_handler
;
503 if (is_global_init(tsk
))
505 if (handler
!= SIG_IGN
&& handler
!= SIG_DFL
)
507 /* if ptraced, let the tracer determine */
512 * Notify the system that a driver wants to block all signals for this
513 * process, and wants to be notified if any signals at all were to be
514 * sent/acted upon. If the notifier routine returns non-zero, then the
515 * signal will be acted upon after all. If the notifier routine returns 0,
516 * then then signal will be blocked. Only one block per process is
517 * allowed. priv is a pointer to private data that the notifier routine
518 * can use to determine if the signal should be blocked or not.
521 block_all_signals(int (*notifier
)(void *priv
), void *priv
, sigset_t
*mask
)
525 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
526 current
->notifier_mask
= mask
;
527 current
->notifier_data
= priv
;
528 current
->notifier
= notifier
;
529 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
532 /* Notify the system that blocking has ended. */
535 unblock_all_signals(void)
539 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
540 current
->notifier
= NULL
;
541 current
->notifier_data
= NULL
;
543 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
546 static void collect_signal(int sig
, struct sigpending
*list
, siginfo_t
*info
)
548 struct sigqueue
*q
, *first
= NULL
;
551 * Collect the siginfo appropriate to this signal. Check if
552 * there is another siginfo for the same signal.
554 list_for_each_entry(q
, &list
->list
, list
) {
555 if (q
->info
.si_signo
== sig
) {
562 sigdelset(&list
->signal
, sig
);
566 list_del_init(&first
->list
);
567 copy_siginfo(info
, &first
->info
);
568 __sigqueue_free(first
);
571 * Ok, it wasn't in the queue. This must be
572 * a fast-pathed signal or we must have been
573 * out of queue space. So zero out the info.
575 info
->si_signo
= sig
;
577 info
->si_code
= SI_USER
;
583 static int __dequeue_signal(struct sigpending
*pending
, sigset_t
*mask
,
586 int sig
= next_signal(pending
, mask
);
589 if (current
->notifier
) {
590 if (sigismember(current
->notifier_mask
, sig
)) {
591 if (!(current
->notifier
)(current
->notifier_data
)) {
592 clear_thread_flag(TIF_SIGPENDING
);
598 collect_signal(sig
, pending
, info
);
605 * Dequeue a signal and return the element to the caller, which is
606 * expected to free it.
608 * All callers have to hold the siglock.
610 int dequeue_signal(struct task_struct
*tsk
, sigset_t
*mask
, siginfo_t
*info
)
614 /* We only dequeue private signals from ourselves, we don't let
615 * signalfd steal them
617 signr
= __dequeue_signal(&tsk
->pending
, mask
, info
);
619 signr
= __dequeue_signal(&tsk
->signal
->shared_pending
,
624 * itimers are process shared and we restart periodic
625 * itimers in the signal delivery path to prevent DoS
626 * attacks in the high resolution timer case. This is
627 * compliant with the old way of self-restarting
628 * itimers, as the SIGALRM is a legacy signal and only
629 * queued once. Changing the restart behaviour to
630 * restart the timer in the signal dequeue path is
631 * reducing the timer noise on heavy loaded !highres
634 if (unlikely(signr
== SIGALRM
)) {
635 struct hrtimer
*tmr
= &tsk
->signal
->real_timer
;
637 if (!hrtimer_is_queued(tmr
) &&
638 tsk
->signal
->it_real_incr
.tv64
!= 0) {
639 hrtimer_forward(tmr
, tmr
->base
->get_time(),
640 tsk
->signal
->it_real_incr
);
641 hrtimer_restart(tmr
);
650 if (unlikely(sig_kernel_stop(signr
))) {
652 * Set a marker that we have dequeued a stop signal. Our
653 * caller might release the siglock and then the pending
654 * stop signal it is about to process is no longer in the
655 * pending bitmasks, but must still be cleared by a SIGCONT
656 * (and overruled by a SIGKILL). So those cases clear this
657 * shared flag after we've set it. Note that this flag may
658 * remain set after the signal we return is ignored or
659 * handled. That doesn't matter because its only purpose
660 * is to alert stop-signal processing code when another
661 * processor has come along and cleared the flag.
663 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
665 if ((info
->si_code
& __SI_MASK
) == __SI_TIMER
&& info
->si_sys_private
) {
667 * Release the siglock to ensure proper locking order
668 * of timer locks outside of siglocks. Note, we leave
669 * irqs disabled here, since the posix-timers code is
670 * about to disable them again anyway.
672 spin_unlock(&tsk
->sighand
->siglock
);
673 do_schedule_next_timer(info
);
674 spin_lock(&tsk
->sighand
->siglock
);
680 * Tell a process that it has a new active signal..
682 * NOTE! we rely on the previous spin_lock to
683 * lock interrupts for us! We can only be called with
684 * "siglock" held, and the local interrupt must
685 * have been disabled when that got acquired!
687 * No need to set need_resched since signal event passing
688 * goes through ->blocked
690 void signal_wake_up_state(struct task_struct
*t
, unsigned int state
)
692 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
694 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
695 * case. We don't check t->state here because there is a race with it
696 * executing another processor and just now entering stopped state.
697 * By using wake_up_state, we ensure the process will wake up and
698 * handle its death signal.
700 if (!wake_up_state(t
, state
| TASK_INTERRUPTIBLE
))
705 * Remove signals in mask from the pending set and queue.
706 * Returns 1 if any signals were found.
708 * All callers must be holding the siglock.
710 static int flush_sigqueue_mask(sigset_t
*mask
, struct sigpending
*s
)
712 struct sigqueue
*q
, *n
;
715 sigandsets(&m
, mask
, &s
->signal
);
716 if (sigisemptyset(&m
))
719 sigandnsets(&s
->signal
, &s
->signal
, mask
);
720 list_for_each_entry_safe(q
, n
, &s
->list
, list
) {
721 if (sigismember(mask
, q
->info
.si_signo
)) {
722 list_del_init(&q
->list
);
729 static inline int is_si_special(const struct siginfo
*info
)
731 return info
<= SEND_SIG_FORCED
;
734 static inline bool si_fromuser(const struct siginfo
*info
)
736 return info
== SEND_SIG_NOINFO
||
737 (!is_si_special(info
) && SI_FROMUSER(info
));
741 * called with RCU read lock from check_kill_permission()
743 static int kill_ok_by_cred(struct task_struct
*t
)
745 const struct cred
*cred
= current_cred();
746 const struct cred
*tcred
= __task_cred(t
);
748 if (uid_eq(cred
->euid
, tcred
->suid
) ||
749 uid_eq(cred
->euid
, tcred
->uid
) ||
750 uid_eq(cred
->uid
, tcred
->suid
) ||
751 uid_eq(cred
->uid
, tcred
->uid
))
754 if (ns_capable(tcred
->user_ns
, CAP_KILL
))
761 * Bad permissions for sending the signal
762 * - the caller must hold the RCU read lock
764 static int check_kill_permission(int sig
, struct siginfo
*info
,
765 struct task_struct
*t
)
770 if (!valid_signal(sig
))
773 if (!si_fromuser(info
))
776 error
= audit_signal_info(sig
, t
); /* Let audit system see the signal */
780 if (!same_thread_group(current
, t
) &&
781 !kill_ok_by_cred(t
)) {
784 sid
= task_session(t
);
786 * We don't return the error if sid == NULL. The
787 * task was unhashed, the caller must notice this.
789 if (!sid
|| sid
== task_session(current
))
796 return security_task_kill(t
, info
, sig
, 0);
800 * ptrace_trap_notify - schedule trap to notify ptracer
801 * @t: tracee wanting to notify tracer
803 * This function schedules sticky ptrace trap which is cleared on the next
804 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
807 * If @t is running, STOP trap will be taken. If trapped for STOP and
808 * ptracer is listening for events, tracee is woken up so that it can
809 * re-trap for the new event. If trapped otherwise, STOP trap will be
810 * eventually taken without returning to userland after the existing traps
811 * are finished by PTRACE_CONT.
814 * Must be called with @task->sighand->siglock held.
816 static void ptrace_trap_notify(struct task_struct
*t
)
818 WARN_ON_ONCE(!(t
->ptrace
& PT_SEIZED
));
819 assert_spin_locked(&t
->sighand
->siglock
);
821 task_set_jobctl_pending(t
, JOBCTL_TRAP_NOTIFY
);
822 ptrace_signal_wake_up(t
, t
->jobctl
& JOBCTL_LISTENING
);
826 * Handle magic process-wide effects of stop/continue signals. Unlike
827 * the signal actions, these happen immediately at signal-generation
828 * time regardless of blocking, ignoring, or handling. This does the
829 * actual continuing for SIGCONT, but not the actual stopping for stop
830 * signals. The process stop is done as a signal action for SIG_DFL.
832 * Returns true if the signal should be actually delivered, otherwise
833 * it should be dropped.
835 static bool prepare_signal(int sig
, struct task_struct
*p
, bool force
)
837 struct signal_struct
*signal
= p
->signal
;
838 struct task_struct
*t
;
841 if (signal
->flags
& (SIGNAL_GROUP_EXIT
| SIGNAL_GROUP_COREDUMP
)) {
842 if (signal
->flags
& SIGNAL_GROUP_COREDUMP
)
843 return sig
== SIGKILL
;
845 * The process is in the middle of dying, nothing to do.
847 } else if (sig_kernel_stop(sig
)) {
849 * This is a stop signal. Remove SIGCONT from all queues.
851 siginitset(&flush
, sigmask(SIGCONT
));
852 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
853 for_each_thread(p
, t
)
854 flush_sigqueue_mask(&flush
, &t
->pending
);
855 } else if (sig
== SIGCONT
) {
858 * Remove all stop signals from all queues, wake all threads.
860 siginitset(&flush
, SIG_KERNEL_STOP_MASK
);
861 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
862 for_each_thread(p
, t
) {
863 flush_sigqueue_mask(&flush
, &t
->pending
);
864 task_clear_jobctl_pending(t
, JOBCTL_STOP_PENDING
);
865 if (likely(!(t
->ptrace
& PT_SEIZED
)))
866 wake_up_state(t
, __TASK_STOPPED
);
868 ptrace_trap_notify(t
);
872 * Notify the parent with CLD_CONTINUED if we were stopped.
874 * If we were in the middle of a group stop, we pretend it
875 * was already finished, and then continued. Since SIGCHLD
876 * doesn't queue we report only CLD_STOPPED, as if the next
877 * CLD_CONTINUED was dropped.
880 if (signal
->flags
& SIGNAL_STOP_STOPPED
)
881 why
|= SIGNAL_CLD_CONTINUED
;
882 else if (signal
->group_stop_count
)
883 why
|= SIGNAL_CLD_STOPPED
;
887 * The first thread which returns from do_signal_stop()
888 * will take ->siglock, notice SIGNAL_CLD_MASK, and
889 * notify its parent. See get_signal_to_deliver().
891 signal
->flags
= why
| SIGNAL_STOP_CONTINUED
;
892 signal
->group_stop_count
= 0;
893 signal
->group_exit_code
= 0;
897 return !sig_ignored(p
, sig
, force
);
901 * Test if P wants to take SIG. After we've checked all threads with this,
902 * it's equivalent to finding no threads not blocking SIG. Any threads not
903 * blocking SIG were ruled out because they are not running and already
904 * have pending signals. Such threads will dequeue from the shared queue
905 * as soon as they're available, so putting the signal on the shared queue
906 * will be equivalent to sending it to one such thread.
908 static inline int wants_signal(int sig
, struct task_struct
*p
)
910 if (sigismember(&p
->blocked
, sig
))
912 if (p
->flags
& PF_EXITING
)
916 if (task_is_stopped_or_traced(p
))
918 return task_curr(p
) || !signal_pending(p
);
921 static void complete_signal(int sig
, struct task_struct
*p
, int group
)
923 struct signal_struct
*signal
= p
->signal
;
924 struct task_struct
*t
;
927 * Now find a thread we can wake up to take the signal off the queue.
929 * If the main thread wants the signal, it gets first crack.
930 * Probably the least surprising to the average bear.
932 if (wants_signal(sig
, p
))
934 else if (!group
|| thread_group_empty(p
))
936 * There is just one thread and it does not need to be woken.
937 * It will dequeue unblocked signals before it runs again.
942 * Otherwise try to find a suitable thread.
944 t
= signal
->curr_target
;
945 while (!wants_signal(sig
, t
)) {
947 if (t
== signal
->curr_target
)
949 * No thread needs to be woken.
950 * Any eligible threads will see
951 * the signal in the queue soon.
955 signal
->curr_target
= t
;
959 * Found a killable thread. If the signal will be fatal,
960 * then start taking the whole group down immediately.
962 if (sig_fatal(p
, sig
) &&
963 !(signal
->flags
& (SIGNAL_UNKILLABLE
| SIGNAL_GROUP_EXIT
)) &&
964 !sigismember(&t
->real_blocked
, sig
) &&
965 (sig
== SIGKILL
|| !t
->ptrace
)) {
967 * This signal will be fatal to the whole group.
969 if (!sig_kernel_coredump(sig
)) {
971 * Start a group exit and wake everybody up.
972 * This way we don't have other threads
973 * running and doing things after a slower
974 * thread has the fatal signal pending.
976 signal
->flags
= SIGNAL_GROUP_EXIT
;
977 signal
->group_exit_code
= sig
;
978 signal
->group_stop_count
= 0;
981 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
982 sigaddset(&t
->pending
.signal
, SIGKILL
);
983 signal_wake_up(t
, 1);
984 } while_each_thread(p
, t
);
990 * The signal is already in the shared-pending queue.
991 * Tell the chosen thread to wake up and dequeue it.
993 signal_wake_up(t
, sig
== SIGKILL
);
997 static inline int legacy_queue(struct sigpending
*signals
, int sig
)
999 return (sig
< SIGRTMIN
) && sigismember(&signals
->signal
, sig
);
1002 #ifdef CONFIG_USER_NS
1003 static inline void userns_fixup_signal_uid(struct siginfo
*info
, struct task_struct
*t
)
1005 if (current_user_ns() == task_cred_xxx(t
, user_ns
))
1008 if (SI_FROMKERNEL(info
))
1012 info
->si_uid
= from_kuid_munged(task_cred_xxx(t
, user_ns
),
1013 make_kuid(current_user_ns(), info
->si_uid
));
1017 static inline void userns_fixup_signal_uid(struct siginfo
*info
, struct task_struct
*t
)
1023 static int __send_signal(int sig
, struct siginfo
*info
, struct task_struct
*t
,
1024 int group
, int from_ancestor_ns
)
1026 struct sigpending
*pending
;
1028 int override_rlimit
;
1029 int ret
= 0, result
;
1031 assert_spin_locked(&t
->sighand
->siglock
);
1033 result
= TRACE_SIGNAL_IGNORED
;
1034 if (!prepare_signal(sig
, t
,
1035 from_ancestor_ns
|| (info
== SEND_SIG_FORCED
)))
1038 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
1040 * Short-circuit ignored signals and support queuing
1041 * exactly one non-rt signal, so that we can get more
1042 * detailed information about the cause of the signal.
1044 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1045 if (legacy_queue(pending
, sig
))
1048 result
= TRACE_SIGNAL_DELIVERED
;
1050 * fast-pathed signals for kernel-internal things like SIGSTOP
1053 if (info
== SEND_SIG_FORCED
)
1057 * Real-time signals must be queued if sent by sigqueue, or
1058 * some other real-time mechanism. It is implementation
1059 * defined whether kill() does so. We attempt to do so, on
1060 * the principle of least surprise, but since kill is not
1061 * allowed to fail with EAGAIN when low on memory we just
1062 * make sure at least one signal gets delivered and don't
1063 * pass on the info struct.
1066 override_rlimit
= (is_si_special(info
) || info
->si_code
>= 0);
1068 override_rlimit
= 0;
1070 q
= __sigqueue_alloc(sig
, t
, GFP_ATOMIC
| __GFP_NOTRACK_FALSE_POSITIVE
,
1073 list_add_tail(&q
->list
, &pending
->list
);
1074 switch ((unsigned long) info
) {
1075 case (unsigned long) SEND_SIG_NOINFO
:
1076 q
->info
.si_signo
= sig
;
1077 q
->info
.si_errno
= 0;
1078 q
->info
.si_code
= SI_USER
;
1079 q
->info
.si_pid
= task_tgid_nr_ns(current
,
1080 task_active_pid_ns(t
));
1081 q
->info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
1083 case (unsigned long) SEND_SIG_PRIV
:
1084 q
->info
.si_signo
= sig
;
1085 q
->info
.si_errno
= 0;
1086 q
->info
.si_code
= SI_KERNEL
;
1091 copy_siginfo(&q
->info
, info
);
1092 if (from_ancestor_ns
)
1097 userns_fixup_signal_uid(&q
->info
, t
);
1099 } else if (!is_si_special(info
)) {
1100 if (sig
>= SIGRTMIN
&& info
->si_code
!= SI_USER
) {
1102 * Queue overflow, abort. We may abort if the
1103 * signal was rt and sent by user using something
1104 * other than kill().
1106 result
= TRACE_SIGNAL_OVERFLOW_FAIL
;
1111 * This is a silent loss of information. We still
1112 * send the signal, but the *info bits are lost.
1114 result
= TRACE_SIGNAL_LOSE_INFO
;
1119 signalfd_notify(t
, sig
);
1120 sigaddset(&pending
->signal
, sig
);
1121 complete_signal(sig
, t
, group
);
1123 trace_signal_generate(sig
, info
, t
, group
, result
);
1127 static int send_signal(int sig
, struct siginfo
*info
, struct task_struct
*t
,
1130 int from_ancestor_ns
= 0;
1132 #ifdef CONFIG_PID_NS
1133 from_ancestor_ns
= si_fromuser(info
) &&
1134 !task_pid_nr_ns(current
, task_active_pid_ns(t
));
1137 return __send_signal(sig
, info
, t
, group
, from_ancestor_ns
);
1140 static void print_fatal_signal(int signr
)
1142 struct pt_regs
*regs
= signal_pt_regs();
1143 printk(KERN_INFO
"potentially unexpected fatal signal %d.\n", signr
);
1145 #if defined(__i386__) && !defined(__arch_um__)
1146 printk(KERN_INFO
"code at %08lx: ", regs
->ip
);
1149 for (i
= 0; i
< 16; i
++) {
1152 if (get_user(insn
, (unsigned char *)(regs
->ip
+ i
)))
1154 printk(KERN_CONT
"%02x ", insn
);
1157 printk(KERN_CONT
"\n");
1164 static int __init
setup_print_fatal_signals(char *str
)
1166 get_option (&str
, &print_fatal_signals
);
1171 __setup("print-fatal-signals=", setup_print_fatal_signals
);
1174 __group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1176 return send_signal(sig
, info
, p
, 1);
1180 specific_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
1182 return send_signal(sig
, info
, t
, 0);
1185 int do_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
,
1188 unsigned long flags
;
1191 if (lock_task_sighand(p
, &flags
)) {
1192 ret
= send_signal(sig
, info
, p
, group
);
1193 unlock_task_sighand(p
, &flags
);
1200 * Force a signal that the process can't ignore: if necessary
1201 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1203 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1204 * since we do not want to have a signal handler that was blocked
1205 * be invoked when user space had explicitly blocked it.
1207 * We don't want to have recursive SIGSEGV's etc, for example,
1208 * that is why we also clear SIGNAL_UNKILLABLE.
1211 force_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
1213 unsigned long int flags
;
1214 int ret
, blocked
, ignored
;
1215 struct k_sigaction
*action
;
1217 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
1218 action
= &t
->sighand
->action
[sig
-1];
1219 ignored
= action
->sa
.sa_handler
== SIG_IGN
;
1220 blocked
= sigismember(&t
->blocked
, sig
);
1221 if (blocked
|| ignored
) {
1222 action
->sa
.sa_handler
= SIG_DFL
;
1224 sigdelset(&t
->blocked
, sig
);
1225 recalc_sigpending_and_wake(t
);
1228 if (action
->sa
.sa_handler
== SIG_DFL
)
1229 t
->signal
->flags
&= ~SIGNAL_UNKILLABLE
;
1230 ret
= specific_send_sig_info(sig
, info
, t
);
1231 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
1237 * Nuke all other threads in the group.
1239 int zap_other_threads(struct task_struct
*p
)
1241 struct task_struct
*t
= p
;
1244 p
->signal
->group_stop_count
= 0;
1246 while_each_thread(p
, t
) {
1247 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
1250 /* Don't bother with already dead threads */
1253 sigaddset(&t
->pending
.signal
, SIGKILL
);
1254 signal_wake_up(t
, 1);
1260 struct sighand_struct
*__lock_task_sighand(struct task_struct
*tsk
,
1261 unsigned long *flags
)
1263 struct sighand_struct
*sighand
;
1267 * Disable interrupts early to avoid deadlocks.
1268 * See rcu_read_unlock() comment header for details.
1270 local_irq_save(*flags
);
1272 sighand
= rcu_dereference(tsk
->sighand
);
1273 if (unlikely(sighand
== NULL
)) {
1275 local_irq_restore(*flags
);
1279 spin_lock(&sighand
->siglock
);
1280 if (likely(sighand
== tsk
->sighand
)) {
1284 spin_unlock(&sighand
->siglock
);
1286 local_irq_restore(*flags
);
1293 * send signal info to all the members of a group
1295 int group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1300 ret
= check_kill_permission(sig
, info
, p
);
1304 ret
= do_send_sig_info(sig
, info
, p
, true);
1310 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1311 * control characters do (^C, ^Z etc)
1312 * - the caller must hold at least a readlock on tasklist_lock
1314 int __kill_pgrp_info(int sig
, struct siginfo
*info
, struct pid
*pgrp
)
1316 struct task_struct
*p
= NULL
;
1317 int retval
, success
;
1321 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
1322 int err
= group_send_sig_info(sig
, info
, p
);
1325 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
1326 return success
? 0 : retval
;
1329 int kill_pid_info(int sig
, struct siginfo
*info
, struct pid
*pid
)
1332 struct task_struct
*p
;
1336 p
= pid_task(pid
, PIDTYPE_PID
);
1338 error
= group_send_sig_info(sig
, info
, p
);
1340 if (likely(!p
|| error
!= -ESRCH
))
1344 * The task was unhashed in between, try again. If it
1345 * is dead, pid_task() will return NULL, if we race with
1346 * de_thread() it will find the new leader.
1351 int kill_proc_info(int sig
, struct siginfo
*info
, pid_t pid
)
1355 error
= kill_pid_info(sig
, info
, find_vpid(pid
));
1360 static int kill_as_cred_perm(const struct cred
*cred
,
1361 struct task_struct
*target
)
1363 const struct cred
*pcred
= __task_cred(target
);
1364 if (!uid_eq(cred
->euid
, pcred
->suid
) && !uid_eq(cred
->euid
, pcred
->uid
) &&
1365 !uid_eq(cred
->uid
, pcred
->suid
) && !uid_eq(cred
->uid
, pcred
->uid
))
1370 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1371 int kill_pid_info_as_cred(int sig
, struct siginfo
*info
, struct pid
*pid
,
1372 const struct cred
*cred
, u32 secid
)
1375 struct task_struct
*p
;
1376 unsigned long flags
;
1378 if (!valid_signal(sig
))
1382 p
= pid_task(pid
, PIDTYPE_PID
);
1387 if (si_fromuser(info
) && !kill_as_cred_perm(cred
, p
)) {
1391 ret
= security_task_kill(p
, info
, sig
, secid
);
1396 if (lock_task_sighand(p
, &flags
)) {
1397 ret
= __send_signal(sig
, info
, p
, 1, 0);
1398 unlock_task_sighand(p
, &flags
);
1406 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred
);
1409 * kill_something_info() interprets pid in interesting ways just like kill(2).
1411 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1412 * is probably wrong. Should make it like BSD or SYSV.
1415 static int kill_something_info(int sig
, struct siginfo
*info
, pid_t pid
)
1421 ret
= kill_pid_info(sig
, info
, find_vpid(pid
));
1426 read_lock(&tasklist_lock
);
1428 ret
= __kill_pgrp_info(sig
, info
,
1429 pid
? find_vpid(-pid
) : task_pgrp(current
));
1431 int retval
= 0, count
= 0;
1432 struct task_struct
* p
;
1434 for_each_process(p
) {
1435 if (task_pid_vnr(p
) > 1 &&
1436 !same_thread_group(p
, current
)) {
1437 int err
= group_send_sig_info(sig
, info
, p
);
1443 ret
= count
? retval
: -ESRCH
;
1445 read_unlock(&tasklist_lock
);
1451 * These are for backward compatibility with the rest of the kernel source.
1454 int send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1457 * Make sure legacy kernel users don't send in bad values
1458 * (normal paths check this in check_kill_permission).
1460 if (!valid_signal(sig
))
1463 return do_send_sig_info(sig
, info
, p
, false);
1466 #define __si_special(priv) \
1467 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1470 send_sig(int sig
, struct task_struct
*p
, int priv
)
1472 return send_sig_info(sig
, __si_special(priv
), p
);
1476 force_sig(int sig
, struct task_struct
*p
)
1478 force_sig_info(sig
, SEND_SIG_PRIV
, p
);
1482 * When things go south during signal handling, we
1483 * will force a SIGSEGV. And if the signal that caused
1484 * the problem was already a SIGSEGV, we'll want to
1485 * make sure we don't even try to deliver the signal..
1488 force_sigsegv(int sig
, struct task_struct
*p
)
1490 if (sig
== SIGSEGV
) {
1491 unsigned long flags
;
1492 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
1493 p
->sighand
->action
[sig
- 1].sa
.sa_handler
= SIG_DFL
;
1494 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
1496 force_sig(SIGSEGV
, p
);
1500 int kill_pgrp(struct pid
*pid
, int sig
, int priv
)
1504 read_lock(&tasklist_lock
);
1505 ret
= __kill_pgrp_info(sig
, __si_special(priv
), pid
);
1506 read_unlock(&tasklist_lock
);
1510 EXPORT_SYMBOL(kill_pgrp
);
1512 int kill_pid(struct pid
*pid
, int sig
, int priv
)
1514 return kill_pid_info(sig
, __si_special(priv
), pid
);
1516 EXPORT_SYMBOL(kill_pid
);
1519 * These functions support sending signals using preallocated sigqueue
1520 * structures. This is needed "because realtime applications cannot
1521 * afford to lose notifications of asynchronous events, like timer
1522 * expirations or I/O completions". In the case of POSIX Timers
1523 * we allocate the sigqueue structure from the timer_create. If this
1524 * allocation fails we are able to report the failure to the application
1525 * with an EAGAIN error.
1527 struct sigqueue
*sigqueue_alloc(void)
1529 struct sigqueue
*q
= __sigqueue_alloc(-1, current
, GFP_KERNEL
, 0);
1532 q
->flags
|= SIGQUEUE_PREALLOC
;
1537 void sigqueue_free(struct sigqueue
*q
)
1539 unsigned long flags
;
1540 spinlock_t
*lock
= ¤t
->sighand
->siglock
;
1542 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1544 * We must hold ->siglock while testing q->list
1545 * to serialize with collect_signal() or with
1546 * __exit_signal()->flush_sigqueue().
1548 spin_lock_irqsave(lock
, flags
);
1549 q
->flags
&= ~SIGQUEUE_PREALLOC
;
1551 * If it is queued it will be freed when dequeued,
1552 * like the "regular" sigqueue.
1554 if (!list_empty(&q
->list
))
1556 spin_unlock_irqrestore(lock
, flags
);
1562 int send_sigqueue(struct sigqueue
*q
, struct task_struct
*t
, int group
)
1564 int sig
= q
->info
.si_signo
;
1565 struct sigpending
*pending
;
1566 unsigned long flags
;
1569 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1572 if (!likely(lock_task_sighand(t
, &flags
)))
1575 ret
= 1; /* the signal is ignored */
1576 result
= TRACE_SIGNAL_IGNORED
;
1577 if (!prepare_signal(sig
, t
, false))
1581 if (unlikely(!list_empty(&q
->list
))) {
1583 * If an SI_TIMER entry is already queue just increment
1584 * the overrun count.
1586 BUG_ON(q
->info
.si_code
!= SI_TIMER
);
1587 q
->info
.si_overrun
++;
1588 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1591 q
->info
.si_overrun
= 0;
1593 signalfd_notify(t
, sig
);
1594 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
1595 list_add_tail(&q
->list
, &pending
->list
);
1596 sigaddset(&pending
->signal
, sig
);
1597 complete_signal(sig
, t
, group
);
1598 result
= TRACE_SIGNAL_DELIVERED
;
1600 trace_signal_generate(sig
, &q
->info
, t
, group
, result
);
1601 unlock_task_sighand(t
, &flags
);
1607 * Let a parent know about the death of a child.
1608 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1610 * Returns true if our parent ignored us and so we've switched to
1613 bool do_notify_parent(struct task_struct
*tsk
, int sig
)
1615 struct siginfo info
;
1616 unsigned long flags
;
1617 struct sighand_struct
*psig
;
1618 bool autoreap
= false;
1619 cputime_t utime
, stime
;
1623 /* do_notify_parent_cldstop should have been called instead. */
1624 BUG_ON(task_is_stopped_or_traced(tsk
));
1626 BUG_ON(!tsk
->ptrace
&&
1627 (tsk
->group_leader
!= tsk
|| !thread_group_empty(tsk
)));
1629 if (sig
!= SIGCHLD
) {
1631 * This is only possible if parent == real_parent.
1632 * Check if it has changed security domain.
1634 if (tsk
->parent_exec_id
!= tsk
->parent
->self_exec_id
)
1638 info
.si_signo
= sig
;
1641 * We are under tasklist_lock here so our parent is tied to
1642 * us and cannot change.
1644 * task_active_pid_ns will always return the same pid namespace
1645 * until a task passes through release_task.
1647 * write_lock() currently calls preempt_disable() which is the
1648 * same as rcu_read_lock(), but according to Oleg, this is not
1649 * correct to rely on this
1652 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(tsk
->parent
));
1653 info
.si_uid
= from_kuid_munged(task_cred_xxx(tsk
->parent
, user_ns
),
1657 task_cputime(tsk
, &utime
, &stime
);
1658 info
.si_utime
= cputime_to_clock_t(utime
+ tsk
->signal
->utime
);
1659 info
.si_stime
= cputime_to_clock_t(stime
+ tsk
->signal
->stime
);
1661 info
.si_status
= tsk
->exit_code
& 0x7f;
1662 if (tsk
->exit_code
& 0x80)
1663 info
.si_code
= CLD_DUMPED
;
1664 else if (tsk
->exit_code
& 0x7f)
1665 info
.si_code
= CLD_KILLED
;
1667 info
.si_code
= CLD_EXITED
;
1668 info
.si_status
= tsk
->exit_code
>> 8;
1671 psig
= tsk
->parent
->sighand
;
1672 spin_lock_irqsave(&psig
->siglock
, flags
);
1673 if (!tsk
->ptrace
&& sig
== SIGCHLD
&&
1674 (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
||
1675 (psig
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDWAIT
))) {
1677 * We are exiting and our parent doesn't care. POSIX.1
1678 * defines special semantics for setting SIGCHLD to SIG_IGN
1679 * or setting the SA_NOCLDWAIT flag: we should be reaped
1680 * automatically and not left for our parent's wait4 call.
1681 * Rather than having the parent do it as a magic kind of
1682 * signal handler, we just set this to tell do_exit that we
1683 * can be cleaned up without becoming a zombie. Note that
1684 * we still call __wake_up_parent in this case, because a
1685 * blocked sys_wait4 might now return -ECHILD.
1687 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1688 * is implementation-defined: we do (if you don't want
1689 * it, just use SIG_IGN instead).
1692 if (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
)
1695 if (valid_signal(sig
) && sig
)
1696 __group_send_sig_info(sig
, &info
, tsk
->parent
);
1697 __wake_up_parent(tsk
, tsk
->parent
);
1698 spin_unlock_irqrestore(&psig
->siglock
, flags
);
1704 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1705 * @tsk: task reporting the state change
1706 * @for_ptracer: the notification is for ptracer
1707 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1709 * Notify @tsk's parent that the stopped/continued state has changed. If
1710 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1711 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1714 * Must be called with tasklist_lock at least read locked.
1716 static void do_notify_parent_cldstop(struct task_struct
*tsk
,
1717 bool for_ptracer
, int why
)
1719 struct siginfo info
;
1720 unsigned long flags
;
1721 struct task_struct
*parent
;
1722 struct sighand_struct
*sighand
;
1723 cputime_t utime
, stime
;
1726 parent
= tsk
->parent
;
1728 tsk
= tsk
->group_leader
;
1729 parent
= tsk
->real_parent
;
1732 info
.si_signo
= SIGCHLD
;
1735 * see comment in do_notify_parent() about the following 4 lines
1738 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(parent
));
1739 info
.si_uid
= from_kuid_munged(task_cred_xxx(parent
, user_ns
), task_uid(tsk
));
1742 task_cputime(tsk
, &utime
, &stime
);
1743 info
.si_utime
= cputime_to_clock_t(utime
);
1744 info
.si_stime
= cputime_to_clock_t(stime
);
1749 info
.si_status
= SIGCONT
;
1752 info
.si_status
= tsk
->signal
->group_exit_code
& 0x7f;
1755 info
.si_status
= tsk
->exit_code
& 0x7f;
1761 sighand
= parent
->sighand
;
1762 spin_lock_irqsave(&sighand
->siglock
, flags
);
1763 if (sighand
->action
[SIGCHLD
-1].sa
.sa_handler
!= SIG_IGN
&&
1764 !(sighand
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDSTOP
))
1765 __group_send_sig_info(SIGCHLD
, &info
, parent
);
1767 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1769 __wake_up_parent(tsk
, parent
);
1770 spin_unlock_irqrestore(&sighand
->siglock
, flags
);
1773 static inline int may_ptrace_stop(void)
1775 if (!likely(current
->ptrace
))
1778 * Are we in the middle of do_coredump?
1779 * If so and our tracer is also part of the coredump stopping
1780 * is a deadlock situation, and pointless because our tracer
1781 * is dead so don't allow us to stop.
1782 * If SIGKILL was already sent before the caller unlocked
1783 * ->siglock we must see ->core_state != NULL. Otherwise it
1784 * is safe to enter schedule().
1786 * This is almost outdated, a task with the pending SIGKILL can't
1787 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1788 * after SIGKILL was already dequeued.
1790 if (unlikely(current
->mm
->core_state
) &&
1791 unlikely(current
->mm
== current
->parent
->mm
))
1798 * Return non-zero if there is a SIGKILL that should be waking us up.
1799 * Called with the siglock held.
1801 static int sigkill_pending(struct task_struct
*tsk
)
1803 return sigismember(&tsk
->pending
.signal
, SIGKILL
) ||
1804 sigismember(&tsk
->signal
->shared_pending
.signal
, SIGKILL
);
1808 * This must be called with current->sighand->siglock held.
1810 * This should be the path for all ptrace stops.
1811 * We always set current->last_siginfo while stopped here.
1812 * That makes it a way to test a stopped process for
1813 * being ptrace-stopped vs being job-control-stopped.
1815 * If we actually decide not to stop at all because the tracer
1816 * is gone, we keep current->exit_code unless clear_code.
1818 static void ptrace_stop(int exit_code
, int why
, int clear_code
, siginfo_t
*info
)
1819 __releases(¤t
->sighand
->siglock
)
1820 __acquires(¤t
->sighand
->siglock
)
1822 bool gstop_done
= false;
1824 if (arch_ptrace_stop_needed(exit_code
, info
)) {
1826 * The arch code has something special to do before a
1827 * ptrace stop. This is allowed to block, e.g. for faults
1828 * on user stack pages. We can't keep the siglock while
1829 * calling arch_ptrace_stop, so we must release it now.
1830 * To preserve proper semantics, we must do this before
1831 * any signal bookkeeping like checking group_stop_count.
1832 * Meanwhile, a SIGKILL could come in before we retake the
1833 * siglock. That must prevent us from sleeping in TASK_TRACED.
1834 * So after regaining the lock, we must check for SIGKILL.
1836 spin_unlock_irq(¤t
->sighand
->siglock
);
1837 arch_ptrace_stop(exit_code
, info
);
1838 spin_lock_irq(¤t
->sighand
->siglock
);
1839 if (sigkill_pending(current
))
1844 * We're committing to trapping. TRACED should be visible before
1845 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1846 * Also, transition to TRACED and updates to ->jobctl should be
1847 * atomic with respect to siglock and should be done after the arch
1848 * hook as siglock is released and regrabbed across it.
1850 set_current_state(TASK_TRACED
);
1852 current
->last_siginfo
= info
;
1853 current
->exit_code
= exit_code
;
1856 * If @why is CLD_STOPPED, we're trapping to participate in a group
1857 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1858 * across siglock relocks since INTERRUPT was scheduled, PENDING
1859 * could be clear now. We act as if SIGCONT is received after
1860 * TASK_TRACED is entered - ignore it.
1862 if (why
== CLD_STOPPED
&& (current
->jobctl
& JOBCTL_STOP_PENDING
))
1863 gstop_done
= task_participate_group_stop(current
);
1865 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1866 task_clear_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
1867 if (info
&& info
->si_code
>> 8 == PTRACE_EVENT_STOP
)
1868 task_clear_jobctl_pending(current
, JOBCTL_TRAP_NOTIFY
);
1870 /* entering a trap, clear TRAPPING */
1871 task_clear_jobctl_trapping(current
);
1873 spin_unlock_irq(¤t
->sighand
->siglock
);
1874 read_lock(&tasklist_lock
);
1875 if (may_ptrace_stop()) {
1877 * Notify parents of the stop.
1879 * While ptraced, there are two parents - the ptracer and
1880 * the real_parent of the group_leader. The ptracer should
1881 * know about every stop while the real parent is only
1882 * interested in the completion of group stop. The states
1883 * for the two don't interact with each other. Notify
1884 * separately unless they're gonna be duplicates.
1886 do_notify_parent_cldstop(current
, true, why
);
1887 if (gstop_done
&& ptrace_reparented(current
))
1888 do_notify_parent_cldstop(current
, false, why
);
1891 * Don't want to allow preemption here, because
1892 * sys_ptrace() needs this task to be inactive.
1894 * XXX: implement read_unlock_no_resched().
1897 read_unlock(&tasklist_lock
);
1898 preempt_enable_no_resched();
1899 freezable_schedule();
1902 * By the time we got the lock, our tracer went away.
1903 * Don't drop the lock yet, another tracer may come.
1905 * If @gstop_done, the ptracer went away between group stop
1906 * completion and here. During detach, it would have set
1907 * JOBCTL_STOP_PENDING on us and we'll re-enter
1908 * TASK_STOPPED in do_signal_stop() on return, so notifying
1909 * the real parent of the group stop completion is enough.
1912 do_notify_parent_cldstop(current
, false, why
);
1914 /* tasklist protects us from ptrace_freeze_traced() */
1915 __set_current_state(TASK_RUNNING
);
1917 current
->exit_code
= 0;
1918 read_unlock(&tasklist_lock
);
1922 * We are back. Now reacquire the siglock before touching
1923 * last_siginfo, so that we are sure to have synchronized with
1924 * any signal-sending on another CPU that wants to examine it.
1926 spin_lock_irq(¤t
->sighand
->siglock
);
1927 current
->last_siginfo
= NULL
;
1929 /* LISTENING can be set only during STOP traps, clear it */
1930 current
->jobctl
&= ~JOBCTL_LISTENING
;
1933 * Queued signals ignored us while we were stopped for tracing.
1934 * So check for any that we should take before resuming user mode.
1935 * This sets TIF_SIGPENDING, but never clears it.
1937 recalc_sigpending_tsk(current
);
1940 static void ptrace_do_notify(int signr
, int exit_code
, int why
)
1944 memset(&info
, 0, sizeof info
);
1945 info
.si_signo
= signr
;
1946 info
.si_code
= exit_code
;
1947 info
.si_pid
= task_pid_vnr(current
);
1948 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
1950 /* Let the debugger run. */
1951 ptrace_stop(exit_code
, why
, 1, &info
);
1954 void ptrace_notify(int exit_code
)
1956 BUG_ON((exit_code
& (0x7f | ~0xffff)) != SIGTRAP
);
1957 if (unlikely(current
->task_works
))
1960 spin_lock_irq(¤t
->sighand
->siglock
);
1961 ptrace_do_notify(SIGTRAP
, exit_code
, CLD_TRAPPED
);
1962 spin_unlock_irq(¤t
->sighand
->siglock
);
1966 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1967 * @signr: signr causing group stop if initiating
1969 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1970 * and participate in it. If already set, participate in the existing
1971 * group stop. If participated in a group stop (and thus slept), %true is
1972 * returned with siglock released.
1974 * If ptraced, this function doesn't handle stop itself. Instead,
1975 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1976 * untouched. The caller must ensure that INTERRUPT trap handling takes
1977 * places afterwards.
1980 * Must be called with @current->sighand->siglock held, which is released
1984 * %false if group stop is already cancelled or ptrace trap is scheduled.
1985 * %true if participated in group stop.
1987 static bool do_signal_stop(int signr
)
1988 __releases(¤t
->sighand
->siglock
)
1990 struct signal_struct
*sig
= current
->signal
;
1992 if (!(current
->jobctl
& JOBCTL_STOP_PENDING
)) {
1993 unsigned int gstop
= JOBCTL_STOP_PENDING
| JOBCTL_STOP_CONSUME
;
1994 struct task_struct
*t
;
1996 /* signr will be recorded in task->jobctl for retries */
1997 WARN_ON_ONCE(signr
& ~JOBCTL_STOP_SIGMASK
);
1999 if (!likely(current
->jobctl
& JOBCTL_STOP_DEQUEUED
) ||
2000 unlikely(signal_group_exit(sig
)))
2003 * There is no group stop already in progress. We must
2006 * While ptraced, a task may be resumed while group stop is
2007 * still in effect and then receive a stop signal and
2008 * initiate another group stop. This deviates from the
2009 * usual behavior as two consecutive stop signals can't
2010 * cause two group stops when !ptraced. That is why we
2011 * also check !task_is_stopped(t) below.
2013 * The condition can be distinguished by testing whether
2014 * SIGNAL_STOP_STOPPED is already set. Don't generate
2015 * group_exit_code in such case.
2017 * This is not necessary for SIGNAL_STOP_CONTINUED because
2018 * an intervening stop signal is required to cause two
2019 * continued events regardless of ptrace.
2021 if (!(sig
->flags
& SIGNAL_STOP_STOPPED
))
2022 sig
->group_exit_code
= signr
;
2024 sig
->group_stop_count
= 0;
2026 if (task_set_jobctl_pending(current
, signr
| gstop
))
2027 sig
->group_stop_count
++;
2030 while_each_thread(current
, t
) {
2032 * Setting state to TASK_STOPPED for a group
2033 * stop is always done with the siglock held,
2034 * so this check has no races.
2036 if (!task_is_stopped(t
) &&
2037 task_set_jobctl_pending(t
, signr
| gstop
)) {
2038 sig
->group_stop_count
++;
2039 if (likely(!(t
->ptrace
& PT_SEIZED
)))
2040 signal_wake_up(t
, 0);
2042 ptrace_trap_notify(t
);
2047 if (likely(!current
->ptrace
)) {
2051 * If there are no other threads in the group, or if there
2052 * is a group stop in progress and we are the last to stop,
2053 * report to the parent.
2055 if (task_participate_group_stop(current
))
2056 notify
= CLD_STOPPED
;
2058 __set_current_state(TASK_STOPPED
);
2059 spin_unlock_irq(¤t
->sighand
->siglock
);
2062 * Notify the parent of the group stop completion. Because
2063 * we're not holding either the siglock or tasklist_lock
2064 * here, ptracer may attach inbetween; however, this is for
2065 * group stop and should always be delivered to the real
2066 * parent of the group leader. The new ptracer will get
2067 * its notification when this task transitions into
2071 read_lock(&tasklist_lock
);
2072 do_notify_parent_cldstop(current
, false, notify
);
2073 read_unlock(&tasklist_lock
);
2076 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2077 freezable_schedule();
2081 * While ptraced, group stop is handled by STOP trap.
2082 * Schedule it and let the caller deal with it.
2084 task_set_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
2090 * do_jobctl_trap - take care of ptrace jobctl traps
2092 * When PT_SEIZED, it's used for both group stop and explicit
2093 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2094 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2095 * the stop signal; otherwise, %SIGTRAP.
2097 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2098 * number as exit_code and no siginfo.
2101 * Must be called with @current->sighand->siglock held, which may be
2102 * released and re-acquired before returning with intervening sleep.
2104 static void do_jobctl_trap(void)
2106 struct signal_struct
*signal
= current
->signal
;
2107 int signr
= current
->jobctl
& JOBCTL_STOP_SIGMASK
;
2109 if (current
->ptrace
& PT_SEIZED
) {
2110 if (!signal
->group_stop_count
&&
2111 !(signal
->flags
& SIGNAL_STOP_STOPPED
))
2113 WARN_ON_ONCE(!signr
);
2114 ptrace_do_notify(signr
, signr
| (PTRACE_EVENT_STOP
<< 8),
2117 WARN_ON_ONCE(!signr
);
2118 ptrace_stop(signr
, CLD_STOPPED
, 0, NULL
);
2119 current
->exit_code
= 0;
2123 static int ptrace_signal(int signr
, siginfo_t
*info
)
2125 ptrace_signal_deliver();
2127 * We do not check sig_kernel_stop(signr) but set this marker
2128 * unconditionally because we do not know whether debugger will
2129 * change signr. This flag has no meaning unless we are going
2130 * to stop after return from ptrace_stop(). In this case it will
2131 * be checked in do_signal_stop(), we should only stop if it was
2132 * not cleared by SIGCONT while we were sleeping. See also the
2133 * comment in dequeue_signal().
2135 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
2136 ptrace_stop(signr
, CLD_TRAPPED
, 0, info
);
2138 /* We're back. Did the debugger cancel the sig? */
2139 signr
= current
->exit_code
;
2143 current
->exit_code
= 0;
2146 * Update the siginfo structure if the signal has
2147 * changed. If the debugger wanted something
2148 * specific in the siginfo structure then it should
2149 * have updated *info via PTRACE_SETSIGINFO.
2151 if (signr
!= info
->si_signo
) {
2152 info
->si_signo
= signr
;
2154 info
->si_code
= SI_USER
;
2156 info
->si_pid
= task_pid_vnr(current
->parent
);
2157 info
->si_uid
= from_kuid_munged(current_user_ns(),
2158 task_uid(current
->parent
));
2162 /* If the (new) signal is now blocked, requeue it. */
2163 if (sigismember(¤t
->blocked
, signr
)) {
2164 specific_send_sig_info(signr
, info
, current
);
2171 int get_signal(struct ksignal
*ksig
)
2173 struct sighand_struct
*sighand
= current
->sighand
;
2174 struct signal_struct
*signal
= current
->signal
;
2177 if (unlikely(current
->task_works
))
2180 if (unlikely(uprobe_deny_signal()))
2184 * Do this once, we can't return to user-mode if freezing() == T.
2185 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2186 * thus do not need another check after return.
2191 spin_lock_irq(&sighand
->siglock
);
2193 * Every stopped thread goes here after wakeup. Check to see if
2194 * we should notify the parent, prepare_signal(SIGCONT) encodes
2195 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2197 if (unlikely(signal
->flags
& SIGNAL_CLD_MASK
)) {
2200 if (signal
->flags
& SIGNAL_CLD_CONTINUED
)
2201 why
= CLD_CONTINUED
;
2205 signal
->flags
&= ~SIGNAL_CLD_MASK
;
2207 spin_unlock_irq(&sighand
->siglock
);
2210 * Notify the parent that we're continuing. This event is
2211 * always per-process and doesn't make whole lot of sense
2212 * for ptracers, who shouldn't consume the state via
2213 * wait(2) either, but, for backward compatibility, notify
2214 * the ptracer of the group leader too unless it's gonna be
2217 read_lock(&tasklist_lock
);
2218 do_notify_parent_cldstop(current
, false, why
);
2220 if (ptrace_reparented(current
->group_leader
))
2221 do_notify_parent_cldstop(current
->group_leader
,
2223 read_unlock(&tasklist_lock
);
2229 struct k_sigaction
*ka
;
2231 if (unlikely(current
->jobctl
& JOBCTL_STOP_PENDING
) &&
2235 if (unlikely(current
->jobctl
& JOBCTL_TRAP_MASK
)) {
2237 spin_unlock_irq(&sighand
->siglock
);
2241 signr
= dequeue_signal(current
, ¤t
->blocked
, &ksig
->info
);
2244 break; /* will return 0 */
2246 if (unlikely(current
->ptrace
) && signr
!= SIGKILL
) {
2247 signr
= ptrace_signal(signr
, &ksig
->info
);
2252 ka
= &sighand
->action
[signr
-1];
2254 /* Trace actually delivered signals. */
2255 trace_signal_deliver(signr
, &ksig
->info
, ka
);
2257 if (ka
->sa
.sa_handler
== SIG_IGN
) /* Do nothing. */
2259 if (ka
->sa
.sa_handler
!= SIG_DFL
) {
2260 /* Run the handler. */
2263 if (ka
->sa
.sa_flags
& SA_ONESHOT
)
2264 ka
->sa
.sa_handler
= SIG_DFL
;
2266 break; /* will return non-zero "signr" value */
2270 * Now we are doing the default action for this signal.
2272 if (sig_kernel_ignore(signr
)) /* Default is nothing. */
2276 * Global init gets no signals it doesn't want.
2277 * Container-init gets no signals it doesn't want from same
2280 * Note that if global/container-init sees a sig_kernel_only()
2281 * signal here, the signal must have been generated internally
2282 * or must have come from an ancestor namespace. In either
2283 * case, the signal cannot be dropped.
2285 if (unlikely(signal
->flags
& SIGNAL_UNKILLABLE
) &&
2286 !sig_kernel_only(signr
))
2289 if (sig_kernel_stop(signr
)) {
2291 * The default action is to stop all threads in
2292 * the thread group. The job control signals
2293 * do nothing in an orphaned pgrp, but SIGSTOP
2294 * always works. Note that siglock needs to be
2295 * dropped during the call to is_orphaned_pgrp()
2296 * because of lock ordering with tasklist_lock.
2297 * This allows an intervening SIGCONT to be posted.
2298 * We need to check for that and bail out if necessary.
2300 if (signr
!= SIGSTOP
) {
2301 spin_unlock_irq(&sighand
->siglock
);
2303 /* signals can be posted during this window */
2305 if (is_current_pgrp_orphaned())
2308 spin_lock_irq(&sighand
->siglock
);
2311 if (likely(do_signal_stop(ksig
->info
.si_signo
))) {
2312 /* It released the siglock. */
2317 * We didn't actually stop, due to a race
2318 * with SIGCONT or something like that.
2323 spin_unlock_irq(&sighand
->siglock
);
2326 * Anything else is fatal, maybe with a core dump.
2328 current
->flags
|= PF_SIGNALED
;
2330 if (sig_kernel_coredump(signr
)) {
2331 if (print_fatal_signals
)
2332 print_fatal_signal(ksig
->info
.si_signo
);
2333 proc_coredump_connector(current
);
2335 * If it was able to dump core, this kills all
2336 * other threads in the group and synchronizes with
2337 * their demise. If we lost the race with another
2338 * thread getting here, it set group_exit_code
2339 * first and our do_group_exit call below will use
2340 * that value and ignore the one we pass it.
2342 do_coredump(&ksig
->info
);
2346 * Death signals, no core dump.
2348 do_group_exit(ksig
->info
.si_signo
);
2351 spin_unlock_irq(&sighand
->siglock
);
2354 return ksig
->sig
> 0;
2358 * signal_delivered -
2359 * @ksig: kernel signal struct
2360 * @stepping: nonzero if debugger single-step or block-step in use
2362 * This function should be called when a signal has successfully been
2363 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2364 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2365 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2367 static void signal_delivered(struct ksignal
*ksig
, int stepping
)
2371 /* A signal was successfully delivered, and the
2372 saved sigmask was stored on the signal frame,
2373 and will be restored by sigreturn. So we can
2374 simply clear the restore sigmask flag. */
2375 clear_restore_sigmask();
2377 sigorsets(&blocked
, ¤t
->blocked
, &ksig
->ka
.sa
.sa_mask
);
2378 if (!(ksig
->ka
.sa
.sa_flags
& SA_NODEFER
))
2379 sigaddset(&blocked
, ksig
->sig
);
2380 set_current_blocked(&blocked
);
2381 tracehook_signal_handler(stepping
);
2384 void signal_setup_done(int failed
, struct ksignal
*ksig
, int stepping
)
2387 force_sigsegv(ksig
->sig
, current
);
2389 signal_delivered(ksig
, stepping
);
2393 * It could be that complete_signal() picked us to notify about the
2394 * group-wide signal. Other threads should be notified now to take
2395 * the shared signals in @which since we will not.
2397 static void retarget_shared_pending(struct task_struct
*tsk
, sigset_t
*which
)
2400 struct task_struct
*t
;
2402 sigandsets(&retarget
, &tsk
->signal
->shared_pending
.signal
, which
);
2403 if (sigisemptyset(&retarget
))
2407 while_each_thread(tsk
, t
) {
2408 if (t
->flags
& PF_EXITING
)
2411 if (!has_pending_signals(&retarget
, &t
->blocked
))
2413 /* Remove the signals this thread can handle. */
2414 sigandsets(&retarget
, &retarget
, &t
->blocked
);
2416 if (!signal_pending(t
))
2417 signal_wake_up(t
, 0);
2419 if (sigisemptyset(&retarget
))
2424 void exit_signals(struct task_struct
*tsk
)
2430 * @tsk is about to have PF_EXITING set - lock out users which
2431 * expect stable threadgroup.
2433 threadgroup_change_begin(tsk
);
2435 if (thread_group_empty(tsk
) || signal_group_exit(tsk
->signal
)) {
2436 tsk
->flags
|= PF_EXITING
;
2437 threadgroup_change_end(tsk
);
2441 spin_lock_irq(&tsk
->sighand
->siglock
);
2443 * From now this task is not visible for group-wide signals,
2444 * see wants_signal(), do_signal_stop().
2446 tsk
->flags
|= PF_EXITING
;
2448 threadgroup_change_end(tsk
);
2450 if (!signal_pending(tsk
))
2453 unblocked
= tsk
->blocked
;
2454 signotset(&unblocked
);
2455 retarget_shared_pending(tsk
, &unblocked
);
2457 if (unlikely(tsk
->jobctl
& JOBCTL_STOP_PENDING
) &&
2458 task_participate_group_stop(tsk
))
2459 group_stop
= CLD_STOPPED
;
2461 spin_unlock_irq(&tsk
->sighand
->siglock
);
2464 * If group stop has completed, deliver the notification. This
2465 * should always go to the real parent of the group leader.
2467 if (unlikely(group_stop
)) {
2468 read_lock(&tasklist_lock
);
2469 do_notify_parent_cldstop(tsk
, false, group_stop
);
2470 read_unlock(&tasklist_lock
);
2474 EXPORT_SYMBOL(recalc_sigpending
);
2475 EXPORT_SYMBOL_GPL(dequeue_signal
);
2476 EXPORT_SYMBOL(flush_signals
);
2477 EXPORT_SYMBOL(force_sig
);
2478 EXPORT_SYMBOL(send_sig
);
2479 EXPORT_SYMBOL(send_sig_info
);
2480 EXPORT_SYMBOL(sigprocmask
);
2481 EXPORT_SYMBOL(block_all_signals
);
2482 EXPORT_SYMBOL(unblock_all_signals
);
2486 * System call entry points.
2490 * sys_restart_syscall - restart a system call
2492 SYSCALL_DEFINE0(restart_syscall
)
2494 struct restart_block
*restart
= ¤t_thread_info()->restart_block
;
2495 return restart
->fn(restart
);
2498 long do_no_restart_syscall(struct restart_block
*param
)
2503 static void __set_task_blocked(struct task_struct
*tsk
, const sigset_t
*newset
)
2505 if (signal_pending(tsk
) && !thread_group_empty(tsk
)) {
2506 sigset_t newblocked
;
2507 /* A set of now blocked but previously unblocked signals. */
2508 sigandnsets(&newblocked
, newset
, ¤t
->blocked
);
2509 retarget_shared_pending(tsk
, &newblocked
);
2511 tsk
->blocked
= *newset
;
2512 recalc_sigpending();
2516 * set_current_blocked - change current->blocked mask
2519 * It is wrong to change ->blocked directly, this helper should be used
2520 * to ensure the process can't miss a shared signal we are going to block.
2522 void set_current_blocked(sigset_t
*newset
)
2524 sigdelsetmask(newset
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2525 __set_current_blocked(newset
);
2528 void __set_current_blocked(const sigset_t
*newset
)
2530 struct task_struct
*tsk
= current
;
2532 spin_lock_irq(&tsk
->sighand
->siglock
);
2533 __set_task_blocked(tsk
, newset
);
2534 spin_unlock_irq(&tsk
->sighand
->siglock
);
2538 * This is also useful for kernel threads that want to temporarily
2539 * (or permanently) block certain signals.
2541 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2542 * interface happily blocks "unblockable" signals like SIGKILL
2545 int sigprocmask(int how
, sigset_t
*set
, sigset_t
*oldset
)
2547 struct task_struct
*tsk
= current
;
2550 /* Lockless, only current can change ->blocked, never from irq */
2552 *oldset
= tsk
->blocked
;
2556 sigorsets(&newset
, &tsk
->blocked
, set
);
2559 sigandnsets(&newset
, &tsk
->blocked
, set
);
2568 __set_current_blocked(&newset
);
2573 * sys_rt_sigprocmask - change the list of currently blocked signals
2574 * @how: whether to add, remove, or set signals
2575 * @nset: stores pending signals
2576 * @oset: previous value of signal mask if non-null
2577 * @sigsetsize: size of sigset_t type
2579 SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, sigset_t __user
*, nset
,
2580 sigset_t __user
*, oset
, size_t, sigsetsize
)
2582 sigset_t old_set
, new_set
;
2585 /* XXX: Don't preclude handling different sized sigset_t's. */
2586 if (sigsetsize
!= sizeof(sigset_t
))
2589 old_set
= current
->blocked
;
2592 if (copy_from_user(&new_set
, nset
, sizeof(sigset_t
)))
2594 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2596 error
= sigprocmask(how
, &new_set
, NULL
);
2602 if (copy_to_user(oset
, &old_set
, sizeof(sigset_t
)))
2609 #ifdef CONFIG_COMPAT
2610 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, compat_sigset_t __user
*, nset
,
2611 compat_sigset_t __user
*, oset
, compat_size_t
, sigsetsize
)
2614 sigset_t old_set
= current
->blocked
;
2616 /* XXX: Don't preclude handling different sized sigset_t's. */
2617 if (sigsetsize
!= sizeof(sigset_t
))
2621 compat_sigset_t new32
;
2624 if (copy_from_user(&new32
, nset
, sizeof(compat_sigset_t
)))
2627 sigset_from_compat(&new_set
, &new32
);
2628 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2630 error
= sigprocmask(how
, &new_set
, NULL
);
2635 compat_sigset_t old32
;
2636 sigset_to_compat(&old32
, &old_set
);
2637 if (copy_to_user(oset
, &old32
, sizeof(compat_sigset_t
)))
2642 return sys_rt_sigprocmask(how
, (sigset_t __user
*)nset
,
2643 (sigset_t __user
*)oset
, sigsetsize
);
2648 static int do_sigpending(void *set
, unsigned long sigsetsize
)
2650 if (sigsetsize
> sizeof(sigset_t
))
2653 spin_lock_irq(¤t
->sighand
->siglock
);
2654 sigorsets(set
, ¤t
->pending
.signal
,
2655 ¤t
->signal
->shared_pending
.signal
);
2656 spin_unlock_irq(¤t
->sighand
->siglock
);
2658 /* Outside the lock because only this thread touches it. */
2659 sigandsets(set
, ¤t
->blocked
, set
);
2664 * sys_rt_sigpending - examine a pending signal that has been raised
2666 * @uset: stores pending signals
2667 * @sigsetsize: size of sigset_t type or larger
2669 SYSCALL_DEFINE2(rt_sigpending
, sigset_t __user
*, uset
, size_t, sigsetsize
)
2672 int err
= do_sigpending(&set
, sigsetsize
);
2673 if (!err
&& copy_to_user(uset
, &set
, sigsetsize
))
2678 #ifdef CONFIG_COMPAT
2679 COMPAT_SYSCALL_DEFINE2(rt_sigpending
, compat_sigset_t __user
*, uset
,
2680 compat_size_t
, sigsetsize
)
2684 int err
= do_sigpending(&set
, sigsetsize
);
2686 compat_sigset_t set32
;
2687 sigset_to_compat(&set32
, &set
);
2688 /* we can get here only if sigsetsize <= sizeof(set) */
2689 if (copy_to_user(uset
, &set32
, sigsetsize
))
2694 return sys_rt_sigpending((sigset_t __user
*)uset
, sigsetsize
);
2699 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2701 int copy_siginfo_to_user(siginfo_t __user
*to
, const siginfo_t
*from
)
2705 if (!access_ok (VERIFY_WRITE
, to
, sizeof(siginfo_t
)))
2707 if (from
->si_code
< 0)
2708 return __copy_to_user(to
, from
, sizeof(siginfo_t
))
2711 * If you change siginfo_t structure, please be sure
2712 * this code is fixed accordingly.
2713 * Please remember to update the signalfd_copyinfo() function
2714 * inside fs/signalfd.c too, in case siginfo_t changes.
2715 * It should never copy any pad contained in the structure
2716 * to avoid security leaks, but must copy the generic
2717 * 3 ints plus the relevant union member.
2719 err
= __put_user(from
->si_signo
, &to
->si_signo
);
2720 err
|= __put_user(from
->si_errno
, &to
->si_errno
);
2721 err
|= __put_user((short)from
->si_code
, &to
->si_code
);
2722 switch (from
->si_code
& __SI_MASK
) {
2724 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2725 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2728 err
|= __put_user(from
->si_tid
, &to
->si_tid
);
2729 err
|= __put_user(from
->si_overrun
, &to
->si_overrun
);
2730 err
|= __put_user(from
->si_ptr
, &to
->si_ptr
);
2733 err
|= __put_user(from
->si_band
, &to
->si_band
);
2734 err
|= __put_user(from
->si_fd
, &to
->si_fd
);
2737 err
|= __put_user(from
->si_addr
, &to
->si_addr
);
2738 #ifdef __ARCH_SI_TRAPNO
2739 err
|= __put_user(from
->si_trapno
, &to
->si_trapno
);
2741 #ifdef BUS_MCEERR_AO
2743 * Other callers might not initialize the si_lsb field,
2744 * so check explicitly for the right codes here.
2746 if (from
->si_code
== BUS_MCEERR_AR
|| from
->si_code
== BUS_MCEERR_AO
)
2747 err
|= __put_user(from
->si_addr_lsb
, &to
->si_addr_lsb
);
2751 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2752 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2753 err
|= __put_user(from
->si_status
, &to
->si_status
);
2754 err
|= __put_user(from
->si_utime
, &to
->si_utime
);
2755 err
|= __put_user(from
->si_stime
, &to
->si_stime
);
2757 case __SI_RT
: /* This is not generated by the kernel as of now. */
2758 case __SI_MESGQ
: /* But this is */
2759 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2760 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2761 err
|= __put_user(from
->si_ptr
, &to
->si_ptr
);
2763 #ifdef __ARCH_SIGSYS
2765 err
|= __put_user(from
->si_call_addr
, &to
->si_call_addr
);
2766 err
|= __put_user(from
->si_syscall
, &to
->si_syscall
);
2767 err
|= __put_user(from
->si_arch
, &to
->si_arch
);
2770 default: /* this is just in case for now ... */
2771 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2772 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2781 * do_sigtimedwait - wait for queued signals specified in @which
2782 * @which: queued signals to wait for
2783 * @info: if non-null, the signal's siginfo is returned here
2784 * @ts: upper bound on process time suspension
2786 int do_sigtimedwait(const sigset_t
*which
, siginfo_t
*info
,
2787 const struct timespec
*ts
)
2789 struct task_struct
*tsk
= current
;
2790 long timeout
= MAX_SCHEDULE_TIMEOUT
;
2791 sigset_t mask
= *which
;
2795 if (!timespec_valid(ts
))
2797 timeout
= timespec_to_jiffies(ts
);
2799 * We can be close to the next tick, add another one
2800 * to ensure we will wait at least the time asked for.
2802 if (ts
->tv_sec
|| ts
->tv_nsec
)
2807 * Invert the set of allowed signals to get those we want to block.
2809 sigdelsetmask(&mask
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2812 spin_lock_irq(&tsk
->sighand
->siglock
);
2813 sig
= dequeue_signal(tsk
, &mask
, info
);
2814 if (!sig
&& timeout
) {
2816 * None ready, temporarily unblock those we're interested
2817 * while we are sleeping in so that we'll be awakened when
2818 * they arrive. Unblocking is always fine, we can avoid
2819 * set_current_blocked().
2821 tsk
->real_blocked
= tsk
->blocked
;
2822 sigandsets(&tsk
->blocked
, &tsk
->blocked
, &mask
);
2823 recalc_sigpending();
2824 spin_unlock_irq(&tsk
->sighand
->siglock
);
2826 timeout
= freezable_schedule_timeout_interruptible(timeout
);
2828 spin_lock_irq(&tsk
->sighand
->siglock
);
2829 __set_task_blocked(tsk
, &tsk
->real_blocked
);
2830 sigemptyset(&tsk
->real_blocked
);
2831 sig
= dequeue_signal(tsk
, &mask
, info
);
2833 spin_unlock_irq(&tsk
->sighand
->siglock
);
2837 return timeout
? -EINTR
: -EAGAIN
;
2841 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2843 * @uthese: queued signals to wait for
2844 * @uinfo: if non-null, the signal's siginfo is returned here
2845 * @uts: upper bound on process time suspension
2846 * @sigsetsize: size of sigset_t type
2848 SYSCALL_DEFINE4(rt_sigtimedwait
, const sigset_t __user
*, uthese
,
2849 siginfo_t __user
*, uinfo
, const struct timespec __user
*, uts
,
2857 /* XXX: Don't preclude handling different sized sigset_t's. */
2858 if (sigsetsize
!= sizeof(sigset_t
))
2861 if (copy_from_user(&these
, uthese
, sizeof(these
)))
2865 if (copy_from_user(&ts
, uts
, sizeof(ts
)))
2869 ret
= do_sigtimedwait(&these
, &info
, uts
? &ts
: NULL
);
2871 if (ret
> 0 && uinfo
) {
2872 if (copy_siginfo_to_user(uinfo
, &info
))
2880 * sys_kill - send a signal to a process
2881 * @pid: the PID of the process
2882 * @sig: signal to be sent
2884 SYSCALL_DEFINE2(kill
, pid_t
, pid
, int, sig
)
2886 struct siginfo info
;
2888 info
.si_signo
= sig
;
2890 info
.si_code
= SI_USER
;
2891 info
.si_pid
= task_tgid_vnr(current
);
2892 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
2894 return kill_something_info(sig
, &info
, pid
);
2898 do_send_specific(pid_t tgid
, pid_t pid
, int sig
, struct siginfo
*info
)
2900 struct task_struct
*p
;
2904 p
= find_task_by_vpid(pid
);
2905 if (p
&& (tgid
<= 0 || task_tgid_vnr(p
) == tgid
)) {
2906 error
= check_kill_permission(sig
, info
, p
);
2908 * The null signal is a permissions and process existence
2909 * probe. No signal is actually delivered.
2911 if (!error
&& sig
) {
2912 error
= do_send_sig_info(sig
, info
, p
, false);
2914 * If lock_task_sighand() failed we pretend the task
2915 * dies after receiving the signal. The window is tiny,
2916 * and the signal is private anyway.
2918 if (unlikely(error
== -ESRCH
))
2927 static int do_tkill(pid_t tgid
, pid_t pid
, int sig
)
2929 struct siginfo info
= {};
2931 info
.si_signo
= sig
;
2933 info
.si_code
= SI_TKILL
;
2934 info
.si_pid
= task_tgid_vnr(current
);
2935 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
2937 return do_send_specific(tgid
, pid
, sig
, &info
);
2941 * sys_tgkill - send signal to one specific thread
2942 * @tgid: the thread group ID of the thread
2943 * @pid: the PID of the thread
2944 * @sig: signal to be sent
2946 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2947 * exists but it's not belonging to the target process anymore. This
2948 * method solves the problem of threads exiting and PIDs getting reused.
2950 SYSCALL_DEFINE3(tgkill
, pid_t
, tgid
, pid_t
, pid
, int, sig
)
2952 /* This is only valid for single tasks */
2953 if (pid
<= 0 || tgid
<= 0)
2956 return do_tkill(tgid
, pid
, sig
);
2960 * sys_tkill - send signal to one specific task
2961 * @pid: the PID of the task
2962 * @sig: signal to be sent
2964 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2966 SYSCALL_DEFINE2(tkill
, pid_t
, pid
, int, sig
)
2968 /* This is only valid for single tasks */
2972 return do_tkill(0, pid
, sig
);
2975 static int do_rt_sigqueueinfo(pid_t pid
, int sig
, siginfo_t
*info
)
2977 /* Not even root can pretend to send signals from the kernel.
2978 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2980 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
2981 (task_pid_vnr(current
) != pid
)) {
2982 /* We used to allow any < 0 si_code */
2983 WARN_ON_ONCE(info
->si_code
< 0);
2986 info
->si_signo
= sig
;
2988 /* POSIX.1b doesn't mention process groups. */
2989 return kill_proc_info(sig
, info
, pid
);
2993 * sys_rt_sigqueueinfo - send signal information to a signal
2994 * @pid: the PID of the thread
2995 * @sig: signal to be sent
2996 * @uinfo: signal info to be sent
2998 SYSCALL_DEFINE3(rt_sigqueueinfo
, pid_t
, pid
, int, sig
,
2999 siginfo_t __user
*, uinfo
)
3002 if (copy_from_user(&info
, uinfo
, sizeof(siginfo_t
)))
3004 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3007 #ifdef CONFIG_COMPAT
3008 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo
,
3011 struct compat_siginfo __user
*, uinfo
)
3014 int ret
= copy_siginfo_from_user32(&info
, uinfo
);
3017 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3021 static int do_rt_tgsigqueueinfo(pid_t tgid
, pid_t pid
, int sig
, siginfo_t
*info
)
3023 /* This is only valid for single tasks */
3024 if (pid
<= 0 || tgid
<= 0)
3027 /* Not even root can pretend to send signals from the kernel.
3028 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3030 if (((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
)) &&
3031 (task_pid_vnr(current
) != pid
)) {
3032 /* We used to allow any < 0 si_code */
3033 WARN_ON_ONCE(info
->si_code
< 0);
3036 info
->si_signo
= sig
;
3038 return do_send_specific(tgid
, pid
, sig
, info
);
3041 SYSCALL_DEFINE4(rt_tgsigqueueinfo
, pid_t
, tgid
, pid_t
, pid
, int, sig
,
3042 siginfo_t __user
*, uinfo
)
3046 if (copy_from_user(&info
, uinfo
, sizeof(siginfo_t
)))
3049 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3052 #ifdef CONFIG_COMPAT
3053 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo
,
3057 struct compat_siginfo __user
*, uinfo
)
3061 if (copy_siginfo_from_user32(&info
, uinfo
))
3063 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3068 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3070 void kernel_sigaction(int sig
, __sighandler_t action
)
3072 spin_lock_irq(¤t
->sighand
->siglock
);
3073 current
->sighand
->action
[sig
- 1].sa
.sa_handler
= action
;
3074 if (action
== SIG_IGN
) {
3078 sigaddset(&mask
, sig
);
3080 flush_sigqueue_mask(&mask
, ¤t
->signal
->shared_pending
);
3081 flush_sigqueue_mask(&mask
, ¤t
->pending
);
3082 recalc_sigpending();
3084 spin_unlock_irq(¤t
->sighand
->siglock
);
3086 EXPORT_SYMBOL(kernel_sigaction
);
3088 int do_sigaction(int sig
, struct k_sigaction
*act
, struct k_sigaction
*oact
)
3090 struct task_struct
*p
= current
, *t
;
3091 struct k_sigaction
*k
;
3094 if (!valid_signal(sig
) || sig
< 1 || (act
&& sig_kernel_only(sig
)))
3097 k
= &p
->sighand
->action
[sig
-1];
3099 spin_lock_irq(&p
->sighand
->siglock
);
3104 sigdelsetmask(&act
->sa
.sa_mask
,
3105 sigmask(SIGKILL
) | sigmask(SIGSTOP
));
3109 * "Setting a signal action to SIG_IGN for a signal that is
3110 * pending shall cause the pending signal to be discarded,
3111 * whether or not it is blocked."
3113 * "Setting a signal action to SIG_DFL for a signal that is
3114 * pending and whose default action is to ignore the signal
3115 * (for example, SIGCHLD), shall cause the pending signal to
3116 * be discarded, whether or not it is blocked"
3118 if (sig_handler_ignored(sig_handler(p
, sig
), sig
)) {
3120 sigaddset(&mask
, sig
);
3121 flush_sigqueue_mask(&mask
, &p
->signal
->shared_pending
);
3122 for_each_thread(p
, t
)
3123 flush_sigqueue_mask(&mask
, &t
->pending
);
3127 spin_unlock_irq(&p
->sighand
->siglock
);
3132 do_sigaltstack (const stack_t __user
*uss
, stack_t __user
*uoss
, unsigned long sp
)
3137 oss
.ss_sp
= (void __user
*) current
->sas_ss_sp
;
3138 oss
.ss_size
= current
->sas_ss_size
;
3139 oss
.ss_flags
= sas_ss_flags(sp
);
3147 if (!access_ok(VERIFY_READ
, uss
, sizeof(*uss
)))
3149 error
= __get_user(ss_sp
, &uss
->ss_sp
) |
3150 __get_user(ss_flags
, &uss
->ss_flags
) |
3151 __get_user(ss_size
, &uss
->ss_size
);
3156 if (on_sig_stack(sp
))
3161 * Note - this code used to test ss_flags incorrectly:
3162 * old code may have been written using ss_flags==0
3163 * to mean ss_flags==SS_ONSTACK (as this was the only
3164 * way that worked) - this fix preserves that older
3167 if (ss_flags
!= SS_DISABLE
&& ss_flags
!= SS_ONSTACK
&& ss_flags
!= 0)
3170 if (ss_flags
== SS_DISABLE
) {
3175 if (ss_size
< MINSIGSTKSZ
)
3179 current
->sas_ss_sp
= (unsigned long) ss_sp
;
3180 current
->sas_ss_size
= ss_size
;
3186 if (!access_ok(VERIFY_WRITE
, uoss
, sizeof(*uoss
)))
3188 error
= __put_user(oss
.ss_sp
, &uoss
->ss_sp
) |
3189 __put_user(oss
.ss_size
, &uoss
->ss_size
) |
3190 __put_user(oss
.ss_flags
, &uoss
->ss_flags
);
3196 SYSCALL_DEFINE2(sigaltstack
,const stack_t __user
*,uss
, stack_t __user
*,uoss
)
3198 return do_sigaltstack(uss
, uoss
, current_user_stack_pointer());
3201 int restore_altstack(const stack_t __user
*uss
)
3203 int err
= do_sigaltstack(uss
, NULL
, current_user_stack_pointer());
3204 /* squash all but EFAULT for now */
3205 return err
== -EFAULT
? err
: 0;
3208 int __save_altstack(stack_t __user
*uss
, unsigned long sp
)
3210 struct task_struct
*t
= current
;
3211 return __put_user((void __user
*)t
->sas_ss_sp
, &uss
->ss_sp
) |
3212 __put_user(sas_ss_flags(sp
), &uss
->ss_flags
) |
3213 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
3216 #ifdef CONFIG_COMPAT
3217 COMPAT_SYSCALL_DEFINE2(sigaltstack
,
3218 const compat_stack_t __user
*, uss_ptr
,
3219 compat_stack_t __user
*, uoss_ptr
)
3226 compat_stack_t uss32
;
3228 memset(&uss
, 0, sizeof(stack_t
));
3229 if (copy_from_user(&uss32
, uss_ptr
, sizeof(compat_stack_t
)))
3231 uss
.ss_sp
= compat_ptr(uss32
.ss_sp
);
3232 uss
.ss_flags
= uss32
.ss_flags
;
3233 uss
.ss_size
= uss32
.ss_size
;
3237 ret
= do_sigaltstack((stack_t __force __user
*) (uss_ptr
? &uss
: NULL
),
3238 (stack_t __force __user
*) &uoss
,
3239 compat_user_stack_pointer());
3241 if (ret
>= 0 && uoss_ptr
) {
3242 if (!access_ok(VERIFY_WRITE
, uoss_ptr
, sizeof(compat_stack_t
)) ||
3243 __put_user(ptr_to_compat(uoss
.ss_sp
), &uoss_ptr
->ss_sp
) ||
3244 __put_user(uoss
.ss_flags
, &uoss_ptr
->ss_flags
) ||
3245 __put_user(uoss
.ss_size
, &uoss_ptr
->ss_size
))
3251 int compat_restore_altstack(const compat_stack_t __user
*uss
)
3253 int err
= compat_sys_sigaltstack(uss
, NULL
);
3254 /* squash all but -EFAULT for now */
3255 return err
== -EFAULT
? err
: 0;
3258 int __compat_save_altstack(compat_stack_t __user
*uss
, unsigned long sp
)
3260 struct task_struct
*t
= current
;
3261 return __put_user(ptr_to_compat((void __user
*)t
->sas_ss_sp
), &uss
->ss_sp
) |
3262 __put_user(sas_ss_flags(sp
), &uss
->ss_flags
) |
3263 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
3267 #ifdef __ARCH_WANT_SYS_SIGPENDING
3270 * sys_sigpending - examine pending signals
3271 * @set: where mask of pending signal is returned
3273 SYSCALL_DEFINE1(sigpending
, old_sigset_t __user
*, set
)
3275 return sys_rt_sigpending((sigset_t __user
*)set
, sizeof(old_sigset_t
));
3280 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3282 * sys_sigprocmask - examine and change blocked signals
3283 * @how: whether to add, remove, or set signals
3284 * @nset: signals to add or remove (if non-null)
3285 * @oset: previous value of signal mask if non-null
3287 * Some platforms have their own version with special arguments;
3288 * others support only sys_rt_sigprocmask.
3291 SYSCALL_DEFINE3(sigprocmask
, int, how
, old_sigset_t __user
*, nset
,
3292 old_sigset_t __user
*, oset
)
3294 old_sigset_t old_set
, new_set
;
3295 sigset_t new_blocked
;
3297 old_set
= current
->blocked
.sig
[0];
3300 if (copy_from_user(&new_set
, nset
, sizeof(*nset
)))
3303 new_blocked
= current
->blocked
;
3307 sigaddsetmask(&new_blocked
, new_set
);
3310 sigdelsetmask(&new_blocked
, new_set
);
3313 new_blocked
.sig
[0] = new_set
;
3319 set_current_blocked(&new_blocked
);
3323 if (copy_to_user(oset
, &old_set
, sizeof(*oset
)))
3329 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3331 #ifndef CONFIG_ODD_RT_SIGACTION
3333 * sys_rt_sigaction - alter an action taken by a process
3334 * @sig: signal to be sent
3335 * @act: new sigaction
3336 * @oact: used to save the previous sigaction
3337 * @sigsetsize: size of sigset_t type
3339 SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
3340 const struct sigaction __user
*, act
,
3341 struct sigaction __user
*, oact
,
3344 struct k_sigaction new_sa
, old_sa
;
3347 /* XXX: Don't preclude handling different sized sigset_t's. */
3348 if (sigsetsize
!= sizeof(sigset_t
))
3352 if (copy_from_user(&new_sa
.sa
, act
, sizeof(new_sa
.sa
)))
3356 ret
= do_sigaction(sig
, act
? &new_sa
: NULL
, oact
? &old_sa
: NULL
);
3359 if (copy_to_user(oact
, &old_sa
.sa
, sizeof(old_sa
.sa
)))
3365 #ifdef CONFIG_COMPAT
3366 COMPAT_SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
3367 const struct compat_sigaction __user
*, act
,
3368 struct compat_sigaction __user
*, oact
,
3369 compat_size_t
, sigsetsize
)
3371 struct k_sigaction new_ka
, old_ka
;
3372 compat_sigset_t mask
;
3373 #ifdef __ARCH_HAS_SA_RESTORER
3374 compat_uptr_t restorer
;
3378 /* XXX: Don't preclude handling different sized sigset_t's. */
3379 if (sigsetsize
!= sizeof(compat_sigset_t
))
3383 compat_uptr_t handler
;
3384 ret
= get_user(handler
, &act
->sa_handler
);
3385 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
3386 #ifdef __ARCH_HAS_SA_RESTORER
3387 ret
|= get_user(restorer
, &act
->sa_restorer
);
3388 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
3390 ret
|= copy_from_user(&mask
, &act
->sa_mask
, sizeof(mask
));
3391 ret
|= get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
);
3394 sigset_from_compat(&new_ka
.sa
.sa_mask
, &mask
);
3397 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3399 sigset_to_compat(&mask
, &old_ka
.sa
.sa_mask
);
3400 ret
= put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
3402 ret
|= copy_to_user(&oact
->sa_mask
, &mask
, sizeof(mask
));
3403 ret
|= put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
);
3404 #ifdef __ARCH_HAS_SA_RESTORER
3405 ret
|= put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
3406 &oact
->sa_restorer
);
3412 #endif /* !CONFIG_ODD_RT_SIGACTION */
3414 #ifdef CONFIG_OLD_SIGACTION
3415 SYSCALL_DEFINE3(sigaction
, int, sig
,
3416 const struct old_sigaction __user
*, act
,
3417 struct old_sigaction __user
*, oact
)
3419 struct k_sigaction new_ka
, old_ka
;
3424 if (!access_ok(VERIFY_READ
, act
, sizeof(*act
)) ||
3425 __get_user(new_ka
.sa
.sa_handler
, &act
->sa_handler
) ||
3426 __get_user(new_ka
.sa
.sa_restorer
, &act
->sa_restorer
) ||
3427 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
3428 __get_user(mask
, &act
->sa_mask
))
3430 #ifdef __ARCH_HAS_KA_RESTORER
3431 new_ka
.ka_restorer
= NULL
;
3433 siginitset(&new_ka
.sa
.sa_mask
, mask
);
3436 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3439 if (!access_ok(VERIFY_WRITE
, oact
, sizeof(*oact
)) ||
3440 __put_user(old_ka
.sa
.sa_handler
, &oact
->sa_handler
) ||
3441 __put_user(old_ka
.sa
.sa_restorer
, &oact
->sa_restorer
) ||
3442 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
3443 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
3450 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3451 COMPAT_SYSCALL_DEFINE3(sigaction
, int, sig
,
3452 const struct compat_old_sigaction __user
*, act
,
3453 struct compat_old_sigaction __user
*, oact
)
3455 struct k_sigaction new_ka
, old_ka
;
3457 compat_old_sigset_t mask
;
3458 compat_uptr_t handler
, restorer
;
3461 if (!access_ok(VERIFY_READ
, act
, sizeof(*act
)) ||
3462 __get_user(handler
, &act
->sa_handler
) ||
3463 __get_user(restorer
, &act
->sa_restorer
) ||
3464 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
3465 __get_user(mask
, &act
->sa_mask
))
3468 #ifdef __ARCH_HAS_KA_RESTORER
3469 new_ka
.ka_restorer
= NULL
;
3471 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
3472 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
3473 siginitset(&new_ka
.sa
.sa_mask
, mask
);
3476 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3479 if (!access_ok(VERIFY_WRITE
, oact
, sizeof(*oact
)) ||
3480 __put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
3481 &oact
->sa_handler
) ||
3482 __put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
3483 &oact
->sa_restorer
) ||
3484 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
3485 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
3492 #ifdef CONFIG_SGETMASK_SYSCALL
3495 * For backwards compatibility. Functionality superseded by sigprocmask.
3497 SYSCALL_DEFINE0(sgetmask
)
3500 return current
->blocked
.sig
[0];
3503 SYSCALL_DEFINE1(ssetmask
, int, newmask
)
3505 int old
= current
->blocked
.sig
[0];
3508 siginitset(&newset
, newmask
);
3509 set_current_blocked(&newset
);
3513 #endif /* CONFIG_SGETMASK_SYSCALL */
3515 #ifdef __ARCH_WANT_SYS_SIGNAL
3517 * For backwards compatibility. Functionality superseded by sigaction.
3519 SYSCALL_DEFINE2(signal
, int, sig
, __sighandler_t
, handler
)
3521 struct k_sigaction new_sa
, old_sa
;
3524 new_sa
.sa
.sa_handler
= handler
;
3525 new_sa
.sa
.sa_flags
= SA_ONESHOT
| SA_NOMASK
;
3526 sigemptyset(&new_sa
.sa
.sa_mask
);
3528 ret
= do_sigaction(sig
, &new_sa
, &old_sa
);
3530 return ret
? ret
: (unsigned long)old_sa
.sa
.sa_handler
;
3532 #endif /* __ARCH_WANT_SYS_SIGNAL */
3534 #ifdef __ARCH_WANT_SYS_PAUSE
3536 SYSCALL_DEFINE0(pause
)
3538 while (!signal_pending(current
)) {
3539 current
->state
= TASK_INTERRUPTIBLE
;
3542 return -ERESTARTNOHAND
;
3547 int sigsuspend(sigset_t
*set
)
3549 current
->saved_sigmask
= current
->blocked
;
3550 set_current_blocked(set
);
3552 current
->state
= TASK_INTERRUPTIBLE
;
3554 set_restore_sigmask();
3555 return -ERESTARTNOHAND
;
3559 * sys_rt_sigsuspend - replace the signal mask for a value with the
3560 * @unewset value until a signal is received
3561 * @unewset: new signal mask value
3562 * @sigsetsize: size of sigset_t type
3564 SYSCALL_DEFINE2(rt_sigsuspend
, sigset_t __user
*, unewset
, size_t, sigsetsize
)
3568 /* XXX: Don't preclude handling different sized sigset_t's. */
3569 if (sigsetsize
!= sizeof(sigset_t
))
3572 if (copy_from_user(&newset
, unewset
, sizeof(newset
)))
3574 return sigsuspend(&newset
);
3577 #ifdef CONFIG_COMPAT
3578 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend
, compat_sigset_t __user
*, unewset
, compat_size_t
, sigsetsize
)
3582 compat_sigset_t newset32
;
3584 /* XXX: Don't preclude handling different sized sigset_t's. */
3585 if (sigsetsize
!= sizeof(sigset_t
))
3588 if (copy_from_user(&newset32
, unewset
, sizeof(compat_sigset_t
)))
3590 sigset_from_compat(&newset
, &newset32
);
3591 return sigsuspend(&newset
);
3593 /* on little-endian bitmaps don't care about granularity */
3594 return sys_rt_sigsuspend((sigset_t __user
*)unewset
, sigsetsize
);
3599 #ifdef CONFIG_OLD_SIGSUSPEND
3600 SYSCALL_DEFINE1(sigsuspend
, old_sigset_t
, mask
)
3603 siginitset(&blocked
, mask
);
3604 return sigsuspend(&blocked
);
3607 #ifdef CONFIG_OLD_SIGSUSPEND3
3608 SYSCALL_DEFINE3(sigsuspend
, int, unused1
, int, unused2
, old_sigset_t
, mask
)
3611 siginitset(&blocked
, mask
);
3612 return sigsuspend(&blocked
);
3616 __weak
const char *arch_vma_name(struct vm_area_struct
*vma
)
3621 void __init
signals_init(void)
3623 sigqueue_cachep
= KMEM_CACHE(sigqueue
, SLAB_PANIC
);
3626 #ifdef CONFIG_KGDB_KDB
3627 #include <linux/kdb.h>
3629 * kdb_send_sig_info - Allows kdb to send signals without exposing
3630 * signal internals. This function checks if the required locks are
3631 * available before calling the main signal code, to avoid kdb
3635 kdb_send_sig_info(struct task_struct
*t
, struct siginfo
*info
)
3637 static struct task_struct
*kdb_prev_t
;
3639 if (!spin_trylock(&t
->sighand
->siglock
)) {
3640 kdb_printf("Can't do kill command now.\n"
3641 "The sigmask lock is held somewhere else in "
3642 "kernel, try again later\n");
3645 spin_unlock(&t
->sighand
->siglock
);
3646 new_t
= kdb_prev_t
!= t
;
3648 if (t
->state
!= TASK_RUNNING
&& new_t
) {
3649 kdb_printf("Process is not RUNNING, sending a signal from "
3650 "kdb risks deadlock\n"
3651 "on the run queue locks. "
3652 "The signal has _not_ been sent.\n"
3653 "Reissue the kill command if you want to risk "
3657 sig
= info
->si_signo
;
3658 if (send_sig_info(sig
, info
, t
))
3659 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3662 kdb_printf("Signal %d is sent to process %d.\n", sig
, t
->pid
);
3664 #endif /* CONFIG_KGDB_KDB */