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1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 LT |
13 | #include <linux/slab.h> |
14 | #include <linux/module.h> | |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
20 | #include <linux/security.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/ptrace.h> | |
7ed20e1a | 23 | #include <linux/signal.h> |
fba2afaa | 24 | #include <linux/signalfd.h> |
c59ede7b | 25 | #include <linux/capability.h> |
7dfb7103 | 26 | #include <linux/freezer.h> |
84d73786 SB |
27 | #include <linux/pid_namespace.h> |
28 | #include <linux/nsproxy.h> | |
29 | ||
1da177e4 LT |
30 | #include <asm/param.h> |
31 | #include <asm/uaccess.h> | |
32 | #include <asm/unistd.h> | |
33 | #include <asm/siginfo.h> | |
e1396065 | 34 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
35 | |
36 | /* | |
37 | * SLAB caches for signal bits. | |
38 | */ | |
39 | ||
e18b890b | 40 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 41 | |
1da177e4 LT |
42 | |
43 | static int sig_ignored(struct task_struct *t, int sig) | |
44 | { | |
45 | void __user * handler; | |
46 | ||
47 | /* | |
48 | * Tracers always want to know about signals.. | |
49 | */ | |
50 | if (t->ptrace & PT_PTRACED) | |
51 | return 0; | |
52 | ||
53 | /* | |
54 | * Blocked signals are never ignored, since the | |
55 | * signal handler may change by the time it is | |
56 | * unblocked. | |
57 | */ | |
325d22df | 58 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
59 | return 0; |
60 | ||
61 | /* Is it explicitly or implicitly ignored? */ | |
62 | handler = t->sighand->action[sig-1].sa.sa_handler; | |
63 | return handler == SIG_IGN || | |
64 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
65 | } | |
66 | ||
67 | /* | |
68 | * Re-calculate pending state from the set of locally pending | |
69 | * signals, globally pending signals, and blocked signals. | |
70 | */ | |
71 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
72 | { | |
73 | unsigned long ready; | |
74 | long i; | |
75 | ||
76 | switch (_NSIG_WORDS) { | |
77 | default: | |
78 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
79 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
80 | break; | |
81 | ||
82 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
83 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
84 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
85 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
86 | break; | |
87 | ||
88 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
89 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
90 | break; | |
91 | ||
92 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
93 | } | |
94 | return ready != 0; | |
95 | } | |
96 | ||
97 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
98 | ||
7bb44ade | 99 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 LT |
100 | { |
101 | if (t->signal->group_stop_count > 0 || | |
102 | PENDING(&t->pending, &t->blocked) || | |
7bb44ade | 103 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 104 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
105 | return 1; |
106 | } | |
b74d0deb RM |
107 | /* |
108 | * We must never clear the flag in another thread, or in current | |
109 | * when it's possible the current syscall is returning -ERESTART*. | |
110 | * So we don't clear it here, and only callers who know they should do. | |
111 | */ | |
7bb44ade RM |
112 | return 0; |
113 | } | |
114 | ||
115 | /* | |
116 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
117 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
118 | */ | |
119 | void recalc_sigpending_and_wake(struct task_struct *t) | |
120 | { | |
121 | if (recalc_sigpending_tsk(t)) | |
122 | signal_wake_up(t, 0); | |
1da177e4 LT |
123 | } |
124 | ||
125 | void recalc_sigpending(void) | |
126 | { | |
cc5f916e | 127 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
128 | clear_thread_flag(TIF_SIGPENDING); |
129 | ||
1da177e4 LT |
130 | } |
131 | ||
132 | /* Given the mask, find the first available signal that should be serviced. */ | |
133 | ||
fba2afaa | 134 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
135 | { |
136 | unsigned long i, *s, *m, x; | |
137 | int sig = 0; | |
138 | ||
139 | s = pending->signal.sig; | |
140 | m = mask->sig; | |
141 | switch (_NSIG_WORDS) { | |
142 | default: | |
143 | for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m) | |
144 | if ((x = *s &~ *m) != 0) { | |
145 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
146 | break; | |
147 | } | |
148 | break; | |
149 | ||
150 | case 2: if ((x = s[0] &~ m[0]) != 0) | |
151 | sig = 1; | |
152 | else if ((x = s[1] &~ m[1]) != 0) | |
153 | sig = _NSIG_BPW + 1; | |
154 | else | |
155 | break; | |
156 | sig += ffz(~x); | |
157 | break; | |
158 | ||
159 | case 1: if ((x = *s &~ *m) != 0) | |
160 | sig = ffz(~x) + 1; | |
161 | break; | |
162 | } | |
163 | ||
164 | return sig; | |
165 | } | |
166 | ||
dd0fc66f | 167 | static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, |
1da177e4 LT |
168 | int override_rlimit) |
169 | { | |
170 | struct sigqueue *q = NULL; | |
10b1fbdb | 171 | struct user_struct *user; |
1da177e4 | 172 | |
10b1fbdb LT |
173 | /* |
174 | * In order to avoid problems with "switch_user()", we want to make | |
175 | * sure that the compiler doesn't re-load "t->user" | |
176 | */ | |
177 | user = t->user; | |
178 | barrier(); | |
179 | atomic_inc(&user->sigpending); | |
1da177e4 | 180 | if (override_rlimit || |
10b1fbdb | 181 | atomic_read(&user->sigpending) <= |
1da177e4 LT |
182 | t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) |
183 | q = kmem_cache_alloc(sigqueue_cachep, flags); | |
184 | if (unlikely(q == NULL)) { | |
10b1fbdb | 185 | atomic_dec(&user->sigpending); |
1da177e4 LT |
186 | } else { |
187 | INIT_LIST_HEAD(&q->list); | |
188 | q->flags = 0; | |
10b1fbdb | 189 | q->user = get_uid(user); |
1da177e4 LT |
190 | } |
191 | return(q); | |
192 | } | |
193 | ||
514a01b8 | 194 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
195 | { |
196 | if (q->flags & SIGQUEUE_PREALLOC) | |
197 | return; | |
198 | atomic_dec(&q->user->sigpending); | |
199 | free_uid(q->user); | |
200 | kmem_cache_free(sigqueue_cachep, q); | |
201 | } | |
202 | ||
6a14c5c9 | 203 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
204 | { |
205 | struct sigqueue *q; | |
206 | ||
207 | sigemptyset(&queue->signal); | |
208 | while (!list_empty(&queue->list)) { | |
209 | q = list_entry(queue->list.next, struct sigqueue , list); | |
210 | list_del_init(&q->list); | |
211 | __sigqueue_free(q); | |
212 | } | |
213 | } | |
214 | ||
215 | /* | |
216 | * Flush all pending signals for a task. | |
217 | */ | |
c81addc9 | 218 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
219 | { |
220 | unsigned long flags; | |
221 | ||
222 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
f5264481 | 223 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 LT |
224 | flush_sigqueue(&t->pending); |
225 | flush_sigqueue(&t->signal->shared_pending); | |
226 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
227 | } | |
228 | ||
10ab825b ON |
229 | void ignore_signals(struct task_struct *t) |
230 | { | |
231 | int i; | |
232 | ||
233 | for (i = 0; i < _NSIG; ++i) | |
234 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
235 | ||
236 | flush_signals(t); | |
237 | } | |
238 | ||
1da177e4 LT |
239 | /* |
240 | * Flush all handlers for a task. | |
241 | */ | |
242 | ||
243 | void | |
244 | flush_signal_handlers(struct task_struct *t, int force_default) | |
245 | { | |
246 | int i; | |
247 | struct k_sigaction *ka = &t->sighand->action[0]; | |
248 | for (i = _NSIG ; i != 0 ; i--) { | |
249 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
250 | ka->sa.sa_handler = SIG_DFL; | |
251 | ka->sa.sa_flags = 0; | |
252 | sigemptyset(&ka->sa.sa_mask); | |
253 | ka++; | |
254 | } | |
255 | } | |
256 | ||
abd4f750 MAS |
257 | int unhandled_signal(struct task_struct *tsk, int sig) |
258 | { | |
b460cbc5 | 259 | if (is_global_init(tsk)) |
abd4f750 MAS |
260 | return 1; |
261 | if (tsk->ptrace & PT_PTRACED) | |
262 | return 0; | |
263 | return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) || | |
264 | (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL); | |
265 | } | |
266 | ||
1da177e4 LT |
267 | |
268 | /* Notify the system that a driver wants to block all signals for this | |
269 | * process, and wants to be notified if any signals at all were to be | |
270 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
271 | * signal will be acted upon after all. If the notifier routine returns 0, | |
272 | * then then signal will be blocked. Only one block per process is | |
273 | * allowed. priv is a pointer to private data that the notifier routine | |
274 | * can use to determine if the signal should be blocked or not. */ | |
275 | ||
276 | void | |
277 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
278 | { | |
279 | unsigned long flags; | |
280 | ||
281 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
282 | current->notifier_mask = mask; | |
283 | current->notifier_data = priv; | |
284 | current->notifier = notifier; | |
285 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
286 | } | |
287 | ||
288 | /* Notify the system that blocking has ended. */ | |
289 | ||
290 | void | |
291 | unblock_all_signals(void) | |
292 | { | |
293 | unsigned long flags; | |
294 | ||
295 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
296 | current->notifier = NULL; | |
297 | current->notifier_data = NULL; | |
298 | recalc_sigpending(); | |
299 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
300 | } | |
301 | ||
858119e1 | 302 | static int collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
303 | { |
304 | struct sigqueue *q, *first = NULL; | |
305 | int still_pending = 0; | |
306 | ||
307 | if (unlikely(!sigismember(&list->signal, sig))) | |
308 | return 0; | |
309 | ||
310 | /* | |
311 | * Collect the siginfo appropriate to this signal. Check if | |
312 | * there is another siginfo for the same signal. | |
313 | */ | |
314 | list_for_each_entry(q, &list->list, list) { | |
315 | if (q->info.si_signo == sig) { | |
316 | if (first) { | |
317 | still_pending = 1; | |
318 | break; | |
319 | } | |
320 | first = q; | |
321 | } | |
322 | } | |
323 | if (first) { | |
324 | list_del_init(&first->list); | |
325 | copy_siginfo(info, &first->info); | |
326 | __sigqueue_free(first); | |
327 | if (!still_pending) | |
328 | sigdelset(&list->signal, sig); | |
329 | } else { | |
330 | ||
331 | /* Ok, it wasn't in the queue. This must be | |
332 | a fast-pathed signal or we must have been | |
333 | out of queue space. So zero out the info. | |
334 | */ | |
335 | sigdelset(&list->signal, sig); | |
336 | info->si_signo = sig; | |
337 | info->si_errno = 0; | |
338 | info->si_code = 0; | |
339 | info->si_pid = 0; | |
340 | info->si_uid = 0; | |
341 | } | |
342 | return 1; | |
343 | } | |
344 | ||
345 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
346 | siginfo_t *info) | |
347 | { | |
27d91e07 | 348 | int sig = next_signal(pending, mask); |
1da177e4 | 349 | |
1da177e4 LT |
350 | if (sig) { |
351 | if (current->notifier) { | |
352 | if (sigismember(current->notifier_mask, sig)) { | |
353 | if (!(current->notifier)(current->notifier_data)) { | |
354 | clear_thread_flag(TIF_SIGPENDING); | |
355 | return 0; | |
356 | } | |
357 | } | |
358 | } | |
359 | ||
360 | if (!collect_signal(sig, pending, info)) | |
361 | sig = 0; | |
1da177e4 | 362 | } |
1da177e4 LT |
363 | |
364 | return sig; | |
365 | } | |
366 | ||
367 | /* | |
368 | * Dequeue a signal and return the element to the caller, which is | |
369 | * expected to free it. | |
370 | * | |
371 | * All callers have to hold the siglock. | |
372 | */ | |
373 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
374 | { | |
caec4e8d BH |
375 | int signr = 0; |
376 | ||
377 | /* We only dequeue private signals from ourselves, we don't let | |
378 | * signalfd steal them | |
379 | */ | |
b8fceee1 | 380 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 381 | if (!signr) { |
1da177e4 LT |
382 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
383 | mask, info); | |
8bfd9a7a TG |
384 | /* |
385 | * itimer signal ? | |
386 | * | |
387 | * itimers are process shared and we restart periodic | |
388 | * itimers in the signal delivery path to prevent DoS | |
389 | * attacks in the high resolution timer case. This is | |
390 | * compliant with the old way of self restarting | |
391 | * itimers, as the SIGALRM is a legacy signal and only | |
392 | * queued once. Changing the restart behaviour to | |
393 | * restart the timer in the signal dequeue path is | |
394 | * reducing the timer noise on heavy loaded !highres | |
395 | * systems too. | |
396 | */ | |
397 | if (unlikely(signr == SIGALRM)) { | |
398 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
399 | ||
400 | if (!hrtimer_is_queued(tmr) && | |
401 | tsk->signal->it_real_incr.tv64 != 0) { | |
402 | hrtimer_forward(tmr, tmr->base->get_time(), | |
403 | tsk->signal->it_real_incr); | |
404 | hrtimer_restart(tmr); | |
405 | } | |
406 | } | |
407 | } | |
b8fceee1 | 408 | recalc_sigpending(); |
8bfd9a7a TG |
409 | if (signr && unlikely(sig_kernel_stop(signr))) { |
410 | /* | |
411 | * Set a marker that we have dequeued a stop signal. Our | |
412 | * caller might release the siglock and then the pending | |
413 | * stop signal it is about to process is no longer in the | |
414 | * pending bitmasks, but must still be cleared by a SIGCONT | |
415 | * (and overruled by a SIGKILL). So those cases clear this | |
416 | * shared flag after we've set it. Note that this flag may | |
417 | * remain set after the signal we return is ignored or | |
418 | * handled. That doesn't matter because its only purpose | |
419 | * is to alert stop-signal processing code when another | |
420 | * processor has come along and cleared the flag. | |
421 | */ | |
422 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) | |
423 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; | |
424 | } | |
b8fceee1 | 425 | if (signr && |
1da177e4 | 426 | ((info->si_code & __SI_MASK) == __SI_TIMER) && |
f5264481 | 427 | info->si_sys_private) { |
1da177e4 LT |
428 | /* |
429 | * Release the siglock to ensure proper locking order | |
430 | * of timer locks outside of siglocks. Note, we leave | |
431 | * irqs disabled here, since the posix-timers code is | |
432 | * about to disable them again anyway. | |
433 | */ | |
434 | spin_unlock(&tsk->sighand->siglock); | |
435 | do_schedule_next_timer(info); | |
436 | spin_lock(&tsk->sighand->siglock); | |
437 | } | |
438 | return signr; | |
439 | } | |
440 | ||
441 | /* | |
442 | * Tell a process that it has a new active signal.. | |
443 | * | |
444 | * NOTE! we rely on the previous spin_lock to | |
445 | * lock interrupts for us! We can only be called with | |
446 | * "siglock" held, and the local interrupt must | |
447 | * have been disabled when that got acquired! | |
448 | * | |
449 | * No need to set need_resched since signal event passing | |
450 | * goes through ->blocked | |
451 | */ | |
452 | void signal_wake_up(struct task_struct *t, int resume) | |
453 | { | |
454 | unsigned int mask; | |
455 | ||
456 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
457 | ||
458 | /* | |
f021a3c2 MW |
459 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
460 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
461 | * executing another processor and just now entering stopped state. |
462 | * By using wake_up_state, we ensure the process will wake up and | |
463 | * handle its death signal. | |
464 | */ | |
465 | mask = TASK_INTERRUPTIBLE; | |
466 | if (resume) | |
f021a3c2 | 467 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
468 | if (!wake_up_state(t, mask)) |
469 | kick_process(t); | |
470 | } | |
471 | ||
71fabd5e GA |
472 | /* |
473 | * Remove signals in mask from the pending set and queue. | |
474 | * Returns 1 if any signals were found. | |
475 | * | |
476 | * All callers must be holding the siglock. | |
477 | * | |
478 | * This version takes a sigset mask and looks at all signals, | |
479 | * not just those in the first mask word. | |
480 | */ | |
481 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
482 | { | |
483 | struct sigqueue *q, *n; | |
484 | sigset_t m; | |
485 | ||
486 | sigandsets(&m, mask, &s->signal); | |
487 | if (sigisemptyset(&m)) | |
488 | return 0; | |
489 | ||
490 | signandsets(&s->signal, &s->signal, mask); | |
491 | list_for_each_entry_safe(q, n, &s->list, list) { | |
492 | if (sigismember(mask, q->info.si_signo)) { | |
493 | list_del_init(&q->list); | |
494 | __sigqueue_free(q); | |
495 | } | |
496 | } | |
497 | return 1; | |
498 | } | |
1da177e4 LT |
499 | /* |
500 | * Remove signals in mask from the pending set and queue. | |
501 | * Returns 1 if any signals were found. | |
502 | * | |
503 | * All callers must be holding the siglock. | |
504 | */ | |
505 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
506 | { | |
507 | struct sigqueue *q, *n; | |
508 | ||
509 | if (!sigtestsetmask(&s->signal, mask)) | |
510 | return 0; | |
511 | ||
512 | sigdelsetmask(&s->signal, mask); | |
513 | list_for_each_entry_safe(q, n, &s->list, list) { | |
514 | if (q->info.si_signo < SIGRTMIN && | |
515 | (mask & sigmask(q->info.si_signo))) { | |
516 | list_del_init(&q->list); | |
517 | __sigqueue_free(q); | |
518 | } | |
519 | } | |
520 | return 1; | |
521 | } | |
522 | ||
523 | /* | |
524 | * Bad permissions for sending the signal | |
525 | */ | |
526 | static int check_kill_permission(int sig, struct siginfo *info, | |
527 | struct task_struct *t) | |
528 | { | |
529 | int error = -EINVAL; | |
7ed20e1a | 530 | if (!valid_signal(sig)) |
1da177e4 | 531 | return error; |
e54dc243 | 532 | |
291041e9 AV |
533 | if (info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) { |
534 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ | |
535 | if (error) | |
536 | return error; | |
537 | error = -EPERM; | |
538 | if (((sig != SIGCONT) || | |
a47afb0f | 539 | (task_session_nr(current) != task_session_nr(t))) |
291041e9 AV |
540 | && (current->euid ^ t->suid) && (current->euid ^ t->uid) |
541 | && (current->uid ^ t->suid) && (current->uid ^ t->uid) | |
542 | && !capable(CAP_KILL)) | |
1da177e4 | 543 | return error; |
291041e9 | 544 | } |
c2f0c7c3 | 545 | |
e54dc243 | 546 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
547 | } |
548 | ||
549 | /* forward decl */ | |
a1d5e21e | 550 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why); |
1da177e4 LT |
551 | |
552 | /* | |
553 | * Handle magic process-wide effects of stop/continue signals. | |
554 | * Unlike the signal actions, these happen immediately at signal-generation | |
555 | * time regardless of blocking, ignoring, or handling. This does the | |
556 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
557 | * signals. The process stop is done as a signal action for SIG_DFL. | |
558 | */ | |
559 | static void handle_stop_signal(int sig, struct task_struct *p) | |
560 | { | |
561 | struct task_struct *t; | |
562 | ||
dd12f48d | 563 | if (p->signal->flags & SIGNAL_GROUP_EXIT) |
1da177e4 LT |
564 | /* |
565 | * The process is in the middle of dying already. | |
566 | */ | |
567 | return; | |
568 | ||
569 | if (sig_kernel_stop(sig)) { | |
570 | /* | |
571 | * This is a stop signal. Remove SIGCONT from all queues. | |
572 | */ | |
573 | rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending); | |
574 | t = p; | |
575 | do { | |
576 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
577 | t = next_thread(t); | |
578 | } while (t != p); | |
579 | } else if (sig == SIGCONT) { | |
580 | /* | |
581 | * Remove all stop signals from all queues, | |
582 | * and wake all threads. | |
583 | */ | |
584 | if (unlikely(p->signal->group_stop_count > 0)) { | |
585 | /* | |
586 | * There was a group stop in progress. We'll | |
587 | * pretend it finished before we got here. We are | |
588 | * obliged to report it to the parent: if the | |
589 | * SIGSTOP happened "after" this SIGCONT, then it | |
590 | * would have cleared this pending SIGCONT. If it | |
591 | * happened "before" this SIGCONT, then the parent | |
592 | * got the SIGCHLD about the stop finishing before | |
593 | * the continue happened. We do the notification | |
594 | * now, and it's as if the stop had finished and | |
595 | * the SIGCHLD was pending on entry to this kill. | |
596 | */ | |
597 | p->signal->group_stop_count = 0; | |
598 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
599 | spin_unlock(&p->sighand->siglock); | |
a1d5e21e | 600 | do_notify_parent_cldstop(p, CLD_STOPPED); |
1da177e4 LT |
601 | spin_lock(&p->sighand->siglock); |
602 | } | |
603 | rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); | |
604 | t = p; | |
605 | do { | |
606 | unsigned int state; | |
607 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
608 | ||
609 | /* | |
610 | * If there is a handler for SIGCONT, we must make | |
611 | * sure that no thread returns to user mode before | |
612 | * we post the signal, in case it was the only | |
613 | * thread eligible to run the signal handler--then | |
614 | * it must not do anything between resuming and | |
615 | * running the handler. With the TIF_SIGPENDING | |
616 | * flag set, the thread will pause and acquire the | |
617 | * siglock that we hold now and until we've queued | |
618 | * the pending signal. | |
619 | * | |
620 | * Wake up the stopped thread _after_ setting | |
621 | * TIF_SIGPENDING | |
622 | */ | |
f021a3c2 | 623 | state = __TASK_STOPPED; |
1da177e4 LT |
624 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { |
625 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
626 | state |= TASK_INTERRUPTIBLE; | |
627 | } | |
628 | wake_up_state(t, state); | |
629 | ||
630 | t = next_thread(t); | |
631 | } while (t != p); | |
632 | ||
633 | if (p->signal->flags & SIGNAL_STOP_STOPPED) { | |
634 | /* | |
635 | * We were in fact stopped, and are now continued. | |
636 | * Notify the parent with CLD_CONTINUED. | |
637 | */ | |
638 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
639 | p->signal->group_exit_code = 0; | |
640 | spin_unlock(&p->sighand->siglock); | |
a1d5e21e | 641 | do_notify_parent_cldstop(p, CLD_CONTINUED); |
1da177e4 LT |
642 | spin_lock(&p->sighand->siglock); |
643 | } else { | |
644 | /* | |
645 | * We are not stopped, but there could be a stop | |
646 | * signal in the middle of being processed after | |
647 | * being removed from the queue. Clear that too. | |
648 | */ | |
649 | p->signal->flags = 0; | |
650 | } | |
651 | } else if (sig == SIGKILL) { | |
652 | /* | |
653 | * Make sure that any pending stop signal already dequeued | |
654 | * is undone by the wakeup for SIGKILL. | |
655 | */ | |
656 | p->signal->flags = 0; | |
657 | } | |
658 | } | |
659 | ||
af7fff9c PE |
660 | static inline int legacy_queue(struct sigpending *signals, int sig) |
661 | { | |
662 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
663 | } | |
664 | ||
1da177e4 LT |
665 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
666 | struct sigpending *signals) | |
667 | { | |
668 | struct sigqueue * q = NULL; | |
1da177e4 | 669 | |
2acb024d PE |
670 | /* |
671 | * Short-circuit ignored signals and support queuing | |
672 | * exactly one non-rt signal, so that we can get more | |
673 | * detailed information about the cause of the signal. | |
674 | */ | |
675 | if (sig_ignored(t, sig) || legacy_queue(signals, sig)) | |
676 | return 0; | |
677 | ||
fba2afaa DL |
678 | /* |
679 | * Deliver the signal to listening signalfds. This must be called | |
680 | * with the sighand lock held. | |
681 | */ | |
682 | signalfd_notify(t, sig); | |
683 | ||
1da177e4 LT |
684 | /* |
685 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
686 | * or SIGKILL. | |
687 | */ | |
b67a1b9e | 688 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
689 | goto out_set; |
690 | ||
691 | /* Real-time signals must be queued if sent by sigqueue, or | |
692 | some other real-time mechanism. It is implementation | |
693 | defined whether kill() does so. We attempt to do so, on | |
694 | the principle of least surprise, but since kill is not | |
695 | allowed to fail with EAGAIN when low on memory we just | |
696 | make sure at least one signal gets delivered and don't | |
697 | pass on the info struct. */ | |
698 | ||
699 | q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN && | |
621d3121 | 700 | (is_si_special(info) || |
1da177e4 LT |
701 | info->si_code >= 0))); |
702 | if (q) { | |
703 | list_add_tail(&q->list, &signals->list); | |
704 | switch ((unsigned long) info) { | |
b67a1b9e | 705 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
706 | q->info.si_signo = sig; |
707 | q->info.si_errno = 0; | |
708 | q->info.si_code = SI_USER; | |
b488893a | 709 | q->info.si_pid = task_pid_vnr(current); |
1da177e4 LT |
710 | q->info.si_uid = current->uid; |
711 | break; | |
b67a1b9e | 712 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
713 | q->info.si_signo = sig; |
714 | q->info.si_errno = 0; | |
715 | q->info.si_code = SI_KERNEL; | |
716 | q->info.si_pid = 0; | |
717 | q->info.si_uid = 0; | |
718 | break; | |
719 | default: | |
720 | copy_siginfo(&q->info, info); | |
721 | break; | |
722 | } | |
621d3121 ON |
723 | } else if (!is_si_special(info)) { |
724 | if (sig >= SIGRTMIN && info->si_code != SI_USER) | |
1da177e4 LT |
725 | /* |
726 | * Queue overflow, abort. We may abort if the signal was rt | |
727 | * and sent by user using something other than kill(). | |
728 | */ | |
729 | return -EAGAIN; | |
1da177e4 LT |
730 | } |
731 | ||
732 | out_set: | |
733 | sigaddset(&signals->signal, sig); | |
2acb024d | 734 | return 1; |
1da177e4 LT |
735 | } |
736 | ||
45807a1d IM |
737 | int print_fatal_signals; |
738 | ||
739 | static void print_fatal_signal(struct pt_regs *regs, int signr) | |
740 | { | |
741 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 742 | current->comm, task_pid_nr(current), signr); |
45807a1d | 743 | |
ca5cd877 | 744 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 745 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
746 | { |
747 | int i; | |
748 | for (i = 0; i < 16; i++) { | |
749 | unsigned char insn; | |
750 | ||
65ea5b03 | 751 | __get_user(insn, (unsigned char *)(regs->ip + i)); |
45807a1d IM |
752 | printk("%02x ", insn); |
753 | } | |
754 | } | |
755 | #endif | |
756 | printk("\n"); | |
757 | show_regs(regs); | |
758 | } | |
759 | ||
760 | static int __init setup_print_fatal_signals(char *str) | |
761 | { | |
762 | get_option (&str, &print_fatal_signals); | |
763 | ||
764 | return 1; | |
765 | } | |
766 | ||
767 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 LT |
768 | |
769 | static int | |
770 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
771 | { | |
2acb024d | 772 | int ret; |
1da177e4 | 773 | |
fda8bd78 | 774 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
775 | assert_spin_locked(&t->sighand->siglock); |
776 | ||
1da177e4 | 777 | ret = send_signal(sig, info, t, &t->pending); |
2acb024d PE |
778 | if (ret <= 0) |
779 | return ret; | |
780 | ||
781 | if (!sigismember(&t->blocked, sig)) | |
1da177e4 | 782 | signal_wake_up(t, sig == SIGKILL); |
2acb024d | 783 | return 0; |
1da177e4 LT |
784 | } |
785 | ||
786 | /* | |
787 | * Force a signal that the process can't ignore: if necessary | |
788 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
789 | * |
790 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
791 | * since we do not want to have a signal handler that was blocked | |
792 | * be invoked when user space had explicitly blocked it. | |
793 | * | |
794 | * We don't want to have recursive SIGSEGV's etc, for example. | |
1da177e4 | 795 | */ |
1da177e4 LT |
796 | int |
797 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
798 | { | |
799 | unsigned long int flags; | |
ae74c3b6 LT |
800 | int ret, blocked, ignored; |
801 | struct k_sigaction *action; | |
1da177e4 LT |
802 | |
803 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
804 | action = &t->sighand->action[sig-1]; |
805 | ignored = action->sa.sa_handler == SIG_IGN; | |
806 | blocked = sigismember(&t->blocked, sig); | |
807 | if (blocked || ignored) { | |
808 | action->sa.sa_handler = SIG_DFL; | |
809 | if (blocked) { | |
810 | sigdelset(&t->blocked, sig); | |
7bb44ade | 811 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 812 | } |
1da177e4 LT |
813 | } |
814 | ret = specific_send_sig_info(sig, info, t); | |
815 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
816 | ||
817 | return ret; | |
818 | } | |
819 | ||
820 | void | |
821 | force_sig_specific(int sig, struct task_struct *t) | |
822 | { | |
b0423a0d | 823 | force_sig_info(sig, SEND_SIG_FORCED, t); |
1da177e4 LT |
824 | } |
825 | ||
826 | /* | |
827 | * Test if P wants to take SIG. After we've checked all threads with this, | |
828 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
829 | * blocking SIG were ruled out because they are not running and already | |
830 | * have pending signals. Such threads will dequeue from the shared queue | |
831 | * as soon as they're available, so putting the signal on the shared queue | |
832 | * will be equivalent to sending it to one such thread. | |
833 | */ | |
188a1eaf LT |
834 | static inline int wants_signal(int sig, struct task_struct *p) |
835 | { | |
836 | if (sigismember(&p->blocked, sig)) | |
837 | return 0; | |
838 | if (p->flags & PF_EXITING) | |
839 | return 0; | |
840 | if (sig == SIGKILL) | |
841 | return 1; | |
e1abb39c | 842 | if (task_is_stopped_or_traced(p)) |
188a1eaf LT |
843 | return 0; |
844 | return task_curr(p) || !signal_pending(p); | |
845 | } | |
1da177e4 LT |
846 | |
847 | static void | |
848 | __group_complete_signal(int sig, struct task_struct *p) | |
849 | { | |
1da177e4 LT |
850 | struct task_struct *t; |
851 | ||
1da177e4 LT |
852 | /* |
853 | * Now find a thread we can wake up to take the signal off the queue. | |
854 | * | |
855 | * If the main thread wants the signal, it gets first crack. | |
856 | * Probably the least surprising to the average bear. | |
857 | */ | |
188a1eaf | 858 | if (wants_signal(sig, p)) |
1da177e4 LT |
859 | t = p; |
860 | else if (thread_group_empty(p)) | |
861 | /* | |
862 | * There is just one thread and it does not need to be woken. | |
863 | * It will dequeue unblocked signals before it runs again. | |
864 | */ | |
865 | return; | |
866 | else { | |
867 | /* | |
868 | * Otherwise try to find a suitable thread. | |
869 | */ | |
870 | t = p->signal->curr_target; | |
871 | if (t == NULL) | |
872 | /* restart balancing at this thread */ | |
873 | t = p->signal->curr_target = p; | |
1da177e4 | 874 | |
188a1eaf | 875 | while (!wants_signal(sig, t)) { |
1da177e4 LT |
876 | t = next_thread(t); |
877 | if (t == p->signal->curr_target) | |
878 | /* | |
879 | * No thread needs to be woken. | |
880 | * Any eligible threads will see | |
881 | * the signal in the queue soon. | |
882 | */ | |
883 | return; | |
884 | } | |
885 | p->signal->curr_target = t; | |
886 | } | |
887 | ||
888 | /* | |
889 | * Found a killable thread. If the signal will be fatal, | |
890 | * then start taking the whole group down immediately. | |
891 | */ | |
892 | if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) && | |
893 | !sigismember(&t->real_blocked, sig) && | |
894 | (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { | |
895 | /* | |
896 | * This signal will be fatal to the whole group. | |
897 | */ | |
898 | if (!sig_kernel_coredump(sig)) { | |
899 | /* | |
900 | * Start a group exit and wake everybody up. | |
901 | * This way we don't have other threads | |
902 | * running and doing things after a slower | |
903 | * thread has the fatal signal pending. | |
904 | */ | |
905 | p->signal->flags = SIGNAL_GROUP_EXIT; | |
906 | p->signal->group_exit_code = sig; | |
907 | p->signal->group_stop_count = 0; | |
908 | t = p; | |
909 | do { | |
910 | sigaddset(&t->pending.signal, SIGKILL); | |
911 | signal_wake_up(t, 1); | |
18442cf2 | 912 | } while_each_thread(p, t); |
1da177e4 LT |
913 | return; |
914 | } | |
1da177e4 LT |
915 | } |
916 | ||
917 | /* | |
918 | * The signal is already in the shared-pending queue. | |
919 | * Tell the chosen thread to wake up and dequeue it. | |
920 | */ | |
921 | signal_wake_up(t, sig == SIGKILL); | |
922 | return; | |
923 | } | |
924 | ||
925 | int | |
926 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
927 | { | |
2acb024d | 928 | int ret; |
1da177e4 LT |
929 | |
930 | assert_spin_locked(&p->sighand->siglock); | |
931 | handle_stop_signal(sig, p); | |
932 | ||
1da177e4 LT |
933 | /* |
934 | * Put this signal on the shared-pending queue, or fail with EAGAIN. | |
935 | * We always use the shared queue for process-wide signals, | |
936 | * to avoid several races. | |
937 | */ | |
938 | ret = send_signal(sig, info, p, &p->signal->shared_pending); | |
2acb024d | 939 | if (ret <= 0) |
1da177e4 LT |
940 | return ret; |
941 | ||
942 | __group_complete_signal(sig, p); | |
943 | return 0; | |
944 | } | |
945 | ||
946 | /* | |
947 | * Nuke all other threads in the group. | |
948 | */ | |
949 | void zap_other_threads(struct task_struct *p) | |
950 | { | |
951 | struct task_struct *t; | |
952 | ||
1da177e4 LT |
953 | p->signal->group_stop_count = 0; |
954 | ||
1da177e4 LT |
955 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
956 | /* | |
957 | * Don't bother with already dead threads | |
958 | */ | |
959 | if (t->exit_state) | |
960 | continue; | |
961 | ||
30e0fca6 | 962 | /* SIGKILL will be handled before any pending SIGSTOP */ |
1da177e4 | 963 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
964 | signal_wake_up(t, 1); |
965 | } | |
966 | } | |
967 | ||
b5606c2d | 968 | int __fatal_signal_pending(struct task_struct *tsk) |
f776d12d MW |
969 | { |
970 | return sigismember(&tsk->pending.signal, SIGKILL); | |
971 | } | |
13f09b95 | 972 | EXPORT_SYMBOL(__fatal_signal_pending); |
f776d12d | 973 | |
1da177e4 | 974 | /* |
e56d0903 | 975 | * Must be called under rcu_read_lock() or with tasklist_lock read-held. |
1da177e4 | 976 | */ |
f63ee72e ON |
977 | struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) |
978 | { | |
979 | struct sighand_struct *sighand; | |
980 | ||
981 | for (;;) { | |
982 | sighand = rcu_dereference(tsk->sighand); | |
983 | if (unlikely(sighand == NULL)) | |
984 | break; | |
985 | ||
986 | spin_lock_irqsave(&sighand->siglock, *flags); | |
987 | if (likely(sighand == tsk->sighand)) | |
988 | break; | |
989 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
990 | } | |
991 | ||
992 | return sighand; | |
993 | } | |
994 | ||
1da177e4 LT |
995 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
996 | { | |
997 | unsigned long flags; | |
998 | int ret; | |
999 | ||
1000 | ret = check_kill_permission(sig, info, p); | |
f63ee72e ON |
1001 | |
1002 | if (!ret && sig) { | |
1003 | ret = -ESRCH; | |
1004 | if (lock_task_sighand(p, &flags)) { | |
1005 | ret = __group_send_sig_info(sig, info, p); | |
1006 | unlock_task_sighand(p, &flags); | |
2d89c929 | 1007 | } |
1da177e4 LT |
1008 | } |
1009 | ||
1010 | return ret; | |
1011 | } | |
1012 | ||
1013 | /* | |
146a505d | 1014 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 LT |
1015 | * control characters do (^C, ^Z etc) |
1016 | */ | |
1017 | ||
c4b92fc1 | 1018 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1019 | { |
1020 | struct task_struct *p = NULL; | |
1021 | int retval, success; | |
1022 | ||
1da177e4 LT |
1023 | success = 0; |
1024 | retval = -ESRCH; | |
c4b92fc1 | 1025 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1026 | int err = group_send_sig_info(sig, info, p); |
1027 | success |= !err; | |
1028 | retval = err; | |
c4b92fc1 | 1029 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1030 | return success ? 0 : retval; |
1031 | } | |
1032 | ||
c4b92fc1 | 1033 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1034 | { |
d36174bc | 1035 | int error = -ESRCH; |
1da177e4 LT |
1036 | struct task_struct *p; |
1037 | ||
e56d0903 | 1038 | rcu_read_lock(); |
0c12b517 | 1039 | if (unlikely(sig_needs_tasklist(sig))) |
e56d0903 | 1040 | read_lock(&tasklist_lock); |
0c12b517 | 1041 | |
d36174bc | 1042 | retry: |
c4b92fc1 | 1043 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1044 | if (p) { |
1da177e4 | 1045 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1046 | if (unlikely(error == -ESRCH)) |
1047 | /* | |
1048 | * The task was unhashed in between, try again. | |
1049 | * If it is dead, pid_task() will return NULL, | |
1050 | * if we race with de_thread() it will find the | |
1051 | * new leader. | |
1052 | */ | |
1053 | goto retry; | |
1054 | } | |
0c12b517 ON |
1055 | |
1056 | if (unlikely(sig_needs_tasklist(sig))) | |
e56d0903 IM |
1057 | read_unlock(&tasklist_lock); |
1058 | rcu_read_unlock(); | |
1da177e4 LT |
1059 | return error; |
1060 | } | |
1061 | ||
c3de4b38 MW |
1062 | int |
1063 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
c4b92fc1 EB |
1064 | { |
1065 | int error; | |
1066 | rcu_read_lock(); | |
b488893a | 1067 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1068 | rcu_read_unlock(); |
1069 | return error; | |
1070 | } | |
1071 | ||
2425c08b EB |
1072 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1073 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1074 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1075 | { |
1076 | int ret = -EINVAL; | |
1077 | struct task_struct *p; | |
1078 | ||
1079 | if (!valid_signal(sig)) | |
1080 | return ret; | |
1081 | ||
1082 | read_lock(&tasklist_lock); | |
2425c08b | 1083 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1084 | if (!p) { |
1085 | ret = -ESRCH; | |
1086 | goto out_unlock; | |
1087 | } | |
0811af28 | 1088 | if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) |
46113830 HW |
1089 | && (euid != p->suid) && (euid != p->uid) |
1090 | && (uid != p->suid) && (uid != p->uid)) { | |
1091 | ret = -EPERM; | |
1092 | goto out_unlock; | |
1093 | } | |
8f95dc58 DQ |
1094 | ret = security_task_kill(p, info, sig, secid); |
1095 | if (ret) | |
1096 | goto out_unlock; | |
46113830 HW |
1097 | if (sig && p->sighand) { |
1098 | unsigned long flags; | |
1099 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1100 | ret = __group_send_sig_info(sig, info, p); | |
1101 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1102 | } | |
1103 | out_unlock: | |
1104 | read_unlock(&tasklist_lock); | |
1105 | return ret; | |
1106 | } | |
2425c08b | 1107 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1108 | |
1109 | /* | |
1110 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1111 | * | |
1112 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1113 | * is probably wrong. Should make it like BSD or SYSV. | |
1114 | */ | |
1115 | ||
1116 | static int kill_something_info(int sig, struct siginfo *info, int pid) | |
1117 | { | |
8d42db18 | 1118 | int ret; |
d5df763b PE |
1119 | |
1120 | if (pid > 0) { | |
1121 | rcu_read_lock(); | |
1122 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1123 | rcu_read_unlock(); | |
1124 | return ret; | |
1125 | } | |
1126 | ||
1127 | read_lock(&tasklist_lock); | |
1128 | if (pid != -1) { | |
1129 | ret = __kill_pgrp_info(sig, info, | |
1130 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1131 | } else { | |
1da177e4 LT |
1132 | int retval = 0, count = 0; |
1133 | struct task_struct * p; | |
1134 | ||
1da177e4 | 1135 | for_each_process(p) { |
bac0abd6 | 1136 | if (p->pid > 1 && !same_thread_group(p, current)) { |
1da177e4 LT |
1137 | int err = group_send_sig_info(sig, info, p); |
1138 | ++count; | |
1139 | if (err != -EPERM) | |
1140 | retval = err; | |
1141 | } | |
1142 | } | |
8d42db18 | 1143 | ret = count ? retval : -ESRCH; |
1da177e4 | 1144 | } |
d5df763b PE |
1145 | read_unlock(&tasklist_lock); |
1146 | ||
8d42db18 | 1147 | return ret; |
1da177e4 LT |
1148 | } |
1149 | ||
1150 | /* | |
1151 | * These are for backward compatibility with the rest of the kernel source. | |
1152 | */ | |
1153 | ||
1154 | /* | |
1155 | * These two are the most common entry points. They send a signal | |
1156 | * just to the specific thread. | |
1157 | */ | |
1158 | int | |
1159 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1160 | { | |
1161 | int ret; | |
1162 | unsigned long flags; | |
1163 | ||
1164 | /* | |
1165 | * Make sure legacy kernel users don't send in bad values | |
1166 | * (normal paths check this in check_kill_permission). | |
1167 | */ | |
7ed20e1a | 1168 | if (!valid_signal(sig)) |
1da177e4 LT |
1169 | return -EINVAL; |
1170 | ||
1171 | /* | |
1172 | * We need the tasklist lock even for the specific | |
1173 | * thread case (when we don't need to follow the group | |
1174 | * lists) in order to avoid races with "p->sighand" | |
1175 | * going away or changing from under us. | |
1176 | */ | |
1177 | read_lock(&tasklist_lock); | |
1178 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1179 | ret = specific_send_sig_info(sig, info, p); | |
1180 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1181 | read_unlock(&tasklist_lock); | |
1182 | return ret; | |
1183 | } | |
1184 | ||
b67a1b9e ON |
1185 | #define __si_special(priv) \ |
1186 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1187 | ||
1da177e4 LT |
1188 | int |
1189 | send_sig(int sig, struct task_struct *p, int priv) | |
1190 | { | |
b67a1b9e | 1191 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1192 | } |
1193 | ||
1da177e4 LT |
1194 | void |
1195 | force_sig(int sig, struct task_struct *p) | |
1196 | { | |
b67a1b9e | 1197 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1198 | } |
1199 | ||
1200 | /* | |
1201 | * When things go south during signal handling, we | |
1202 | * will force a SIGSEGV. And if the signal that caused | |
1203 | * the problem was already a SIGSEGV, we'll want to | |
1204 | * make sure we don't even try to deliver the signal.. | |
1205 | */ | |
1206 | int | |
1207 | force_sigsegv(int sig, struct task_struct *p) | |
1208 | { | |
1209 | if (sig == SIGSEGV) { | |
1210 | unsigned long flags; | |
1211 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1212 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1213 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1214 | } | |
1215 | force_sig(SIGSEGV, p); | |
1216 | return 0; | |
1217 | } | |
1218 | ||
c4b92fc1 EB |
1219 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1220 | { | |
146a505d PE |
1221 | int ret; |
1222 | ||
1223 | read_lock(&tasklist_lock); | |
1224 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1225 | read_unlock(&tasklist_lock); | |
1226 | ||
1227 | return ret; | |
c4b92fc1 EB |
1228 | } |
1229 | EXPORT_SYMBOL(kill_pgrp); | |
1230 | ||
1231 | int kill_pid(struct pid *pid, int sig, int priv) | |
1232 | { | |
1233 | return kill_pid_info(sig, __si_special(priv), pid); | |
1234 | } | |
1235 | EXPORT_SYMBOL(kill_pid); | |
1236 | ||
1da177e4 LT |
1237 | int |
1238 | kill_proc(pid_t pid, int sig, int priv) | |
1239 | { | |
b488893a PE |
1240 | int ret; |
1241 | ||
1242 | rcu_read_lock(); | |
1243 | ret = kill_pid_info(sig, __si_special(priv), find_pid(pid)); | |
1244 | rcu_read_unlock(); | |
1245 | return ret; | |
1da177e4 LT |
1246 | } |
1247 | ||
1248 | /* | |
1249 | * These functions support sending signals using preallocated sigqueue | |
1250 | * structures. This is needed "because realtime applications cannot | |
1251 | * afford to lose notifications of asynchronous events, like timer | |
1252 | * expirations or I/O completions". In the case of Posix Timers | |
1253 | * we allocate the sigqueue structure from the timer_create. If this | |
1254 | * allocation fails we are able to report the failure to the application | |
1255 | * with an EAGAIN error. | |
1256 | */ | |
1257 | ||
1258 | struct sigqueue *sigqueue_alloc(void) | |
1259 | { | |
1260 | struct sigqueue *q; | |
1261 | ||
1262 | if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) | |
1263 | q->flags |= SIGQUEUE_PREALLOC; | |
1264 | return(q); | |
1265 | } | |
1266 | ||
1267 | void sigqueue_free(struct sigqueue *q) | |
1268 | { | |
1269 | unsigned long flags; | |
60187d27 ON |
1270 | spinlock_t *lock = ¤t->sighand->siglock; |
1271 | ||
1da177e4 LT |
1272 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1273 | /* | |
1274 | * If the signal is still pending remove it from the | |
60187d27 ON |
1275 | * pending queue. We must hold ->siglock while testing |
1276 | * q->list to serialize with collect_signal(). | |
1da177e4 | 1277 | */ |
60187d27 ON |
1278 | spin_lock_irqsave(lock, flags); |
1279 | if (!list_empty(&q->list)) | |
1280 | list_del_init(&q->list); | |
1281 | spin_unlock_irqrestore(lock, flags); | |
1282 | ||
1da177e4 LT |
1283 | q->flags &= ~SIGQUEUE_PREALLOC; |
1284 | __sigqueue_free(q); | |
1285 | } | |
1286 | ||
54767908 | 1287 | int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) |
1da177e4 LT |
1288 | { |
1289 | unsigned long flags; | |
1290 | int ret = 0; | |
1291 | ||
1da177e4 | 1292 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e56d0903 IM |
1293 | |
1294 | /* | |
1295 | * The rcu based delayed sighand destroy makes it possible to | |
1296 | * run this without tasklist lock held. The task struct itself | |
1297 | * cannot go away as create_timer did get_task_struct(). | |
1298 | * | |
1299 | * We return -1, when the task is marked exiting, so | |
1300 | * posix_timer_event can redirect it to the group leader | |
1301 | */ | |
1302 | rcu_read_lock(); | |
e752dd6c | 1303 | |
54767908 | 1304 | if (!likely(lock_task_sighand(p, &flags))) { |
e752dd6c ON |
1305 | ret = -1; |
1306 | goto out_err; | |
1307 | } | |
1308 | ||
1da177e4 LT |
1309 | if (unlikely(!list_empty(&q->list))) { |
1310 | /* | |
1311 | * If an SI_TIMER entry is already queue just increment | |
1312 | * the overrun count. | |
1313 | */ | |
54767908 | 1314 | BUG_ON(q->info.si_code != SI_TIMER); |
1da177e4 LT |
1315 | q->info.si_overrun++; |
1316 | goto out; | |
e752dd6c | 1317 | } |
1da177e4 LT |
1318 | /* Short-circuit ignored signals. */ |
1319 | if (sig_ignored(p, sig)) { | |
1320 | ret = 1; | |
1321 | goto out; | |
1322 | } | |
fba2afaa DL |
1323 | /* |
1324 | * Deliver the signal to listening signalfds. This must be called | |
1325 | * with the sighand lock held. | |
1326 | */ | |
1327 | signalfd_notify(p, sig); | |
1da177e4 | 1328 | |
1da177e4 LT |
1329 | list_add_tail(&q->list, &p->pending.list); |
1330 | sigaddset(&p->pending.signal, sig); | |
1331 | if (!sigismember(&p->blocked, sig)) | |
1332 | signal_wake_up(p, sig == SIGKILL); | |
1333 | ||
1334 | out: | |
54767908 | 1335 | unlock_task_sighand(p, &flags); |
e752dd6c | 1336 | out_err: |
e56d0903 | 1337 | rcu_read_unlock(); |
e752dd6c ON |
1338 | |
1339 | return ret; | |
1da177e4 LT |
1340 | } |
1341 | ||
1342 | int | |
1343 | send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) | |
1344 | { | |
1345 | unsigned long flags; | |
1346 | int ret = 0; | |
1347 | ||
1348 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); | |
e56d0903 | 1349 | |
1da177e4 | 1350 | read_lock(&tasklist_lock); |
e56d0903 | 1351 | /* Since it_lock is held, p->sighand cannot be NULL. */ |
1da177e4 LT |
1352 | spin_lock_irqsave(&p->sighand->siglock, flags); |
1353 | handle_stop_signal(sig, p); | |
1354 | ||
1355 | /* Short-circuit ignored signals. */ | |
1356 | if (sig_ignored(p, sig)) { | |
1357 | ret = 1; | |
1358 | goto out; | |
1359 | } | |
1360 | ||
1361 | if (unlikely(!list_empty(&q->list))) { | |
1362 | /* | |
1363 | * If an SI_TIMER entry is already queue just increment | |
1364 | * the overrun count. Other uses should not try to | |
1365 | * send the signal multiple times. | |
1366 | */ | |
fda8bd78 | 1367 | BUG_ON(q->info.si_code != SI_TIMER); |
1da177e4 LT |
1368 | q->info.si_overrun++; |
1369 | goto out; | |
1370 | } | |
fba2afaa DL |
1371 | /* |
1372 | * Deliver the signal to listening signalfds. This must be called | |
1373 | * with the sighand lock held. | |
1374 | */ | |
1375 | signalfd_notify(p, sig); | |
1da177e4 LT |
1376 | |
1377 | /* | |
1378 | * Put this signal on the shared-pending queue. | |
1379 | * We always use the shared queue for process-wide signals, | |
1380 | * to avoid several races. | |
1381 | */ | |
1da177e4 LT |
1382 | list_add_tail(&q->list, &p->signal->shared_pending.list); |
1383 | sigaddset(&p->signal->shared_pending.signal, sig); | |
1384 | ||
1385 | __group_complete_signal(sig, p); | |
1386 | out: | |
1387 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1388 | read_unlock(&tasklist_lock); | |
e56d0903 | 1389 | return ret; |
1da177e4 LT |
1390 | } |
1391 | ||
1392 | /* | |
1393 | * Wake up any threads in the parent blocked in wait* syscalls. | |
1394 | */ | |
1395 | static inline void __wake_up_parent(struct task_struct *p, | |
1396 | struct task_struct *parent) | |
1397 | { | |
1398 | wake_up_interruptible_sync(&parent->signal->wait_chldexit); | |
1399 | } | |
1400 | ||
1401 | /* | |
1402 | * Let a parent know about the death of a child. | |
1403 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
1404 | */ | |
1405 | ||
1406 | void do_notify_parent(struct task_struct *tsk, int sig) | |
1407 | { | |
1408 | struct siginfo info; | |
1409 | unsigned long flags; | |
1410 | struct sighand_struct *psig; | |
1411 | ||
1412 | BUG_ON(sig == -1); | |
1413 | ||
1414 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1415 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 LT |
1416 | |
1417 | BUG_ON(!tsk->ptrace && | |
1418 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); | |
1419 | ||
1420 | info.si_signo = sig; | |
1421 | info.si_errno = 0; | |
b488893a PE |
1422 | /* |
1423 | * we are under tasklist_lock here so our parent is tied to | |
1424 | * us and cannot exit and release its namespace. | |
1425 | * | |
1426 | * the only it can is to switch its nsproxy with sys_unshare, | |
1427 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1428 | * see relevant namespace | |
1429 | * | |
1430 | * write_lock() currently calls preempt_disable() which is the | |
1431 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1432 | * correct to rely on this | |
1433 | */ | |
1434 | rcu_read_lock(); | |
1435 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
1436 | rcu_read_unlock(); | |
1437 | ||
1da177e4 LT |
1438 | info.si_uid = tsk->uid; |
1439 | ||
1440 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1441 | info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime, | |
1442 | tsk->signal->utime)); | |
1443 | info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime, | |
1444 | tsk->signal->stime)); | |
1445 | ||
1446 | info.si_status = tsk->exit_code & 0x7f; | |
1447 | if (tsk->exit_code & 0x80) | |
1448 | info.si_code = CLD_DUMPED; | |
1449 | else if (tsk->exit_code & 0x7f) | |
1450 | info.si_code = CLD_KILLED; | |
1451 | else { | |
1452 | info.si_code = CLD_EXITED; | |
1453 | info.si_status = tsk->exit_code >> 8; | |
1454 | } | |
1455 | ||
1456 | psig = tsk->parent->sighand; | |
1457 | spin_lock_irqsave(&psig->siglock, flags); | |
7ed0175a | 1458 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1459 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1460 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1461 | /* | |
1462 | * We are exiting and our parent doesn't care. POSIX.1 | |
1463 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1464 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1465 | * automatically and not left for our parent's wait4 call. | |
1466 | * Rather than having the parent do it as a magic kind of | |
1467 | * signal handler, we just set this to tell do_exit that we | |
1468 | * can be cleaned up without becoming a zombie. Note that | |
1469 | * we still call __wake_up_parent in this case, because a | |
1470 | * blocked sys_wait4 might now return -ECHILD. | |
1471 | * | |
1472 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1473 | * is implementation-defined: we do (if you don't want | |
1474 | * it, just use SIG_IGN instead). | |
1475 | */ | |
1476 | tsk->exit_signal = -1; | |
1477 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) | |
1478 | sig = 0; | |
1479 | } | |
7ed20e1a | 1480 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1481 | __group_send_sig_info(sig, &info, tsk->parent); |
1482 | __wake_up_parent(tsk, tsk->parent); | |
1483 | spin_unlock_irqrestore(&psig->siglock, flags); | |
1484 | } | |
1485 | ||
a1d5e21e | 1486 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why) |
1da177e4 LT |
1487 | { |
1488 | struct siginfo info; | |
1489 | unsigned long flags; | |
bc505a47 | 1490 | struct task_struct *parent; |
1da177e4 LT |
1491 | struct sighand_struct *sighand; |
1492 | ||
a1d5e21e | 1493 | if (tsk->ptrace & PT_PTRACED) |
bc505a47 ON |
1494 | parent = tsk->parent; |
1495 | else { | |
1496 | tsk = tsk->group_leader; | |
1497 | parent = tsk->real_parent; | |
1498 | } | |
1499 | ||
1da177e4 LT |
1500 | info.si_signo = SIGCHLD; |
1501 | info.si_errno = 0; | |
b488893a PE |
1502 | /* |
1503 | * see comment in do_notify_parent() abot the following 3 lines | |
1504 | */ | |
1505 | rcu_read_lock(); | |
1506 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
1507 | rcu_read_unlock(); | |
1508 | ||
1da177e4 LT |
1509 | info.si_uid = tsk->uid; |
1510 | ||
1511 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1512 | info.si_utime = cputime_to_jiffies(tsk->utime); | |
1513 | info.si_stime = cputime_to_jiffies(tsk->stime); | |
1514 | ||
1515 | info.si_code = why; | |
1516 | switch (why) { | |
1517 | case CLD_CONTINUED: | |
1518 | info.si_status = SIGCONT; | |
1519 | break; | |
1520 | case CLD_STOPPED: | |
1521 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1522 | break; | |
1523 | case CLD_TRAPPED: | |
1524 | info.si_status = tsk->exit_code & 0x7f; | |
1525 | break; | |
1526 | default: | |
1527 | BUG(); | |
1528 | } | |
1529 | ||
1530 | sighand = parent->sighand; | |
1531 | spin_lock_irqsave(&sighand->siglock, flags); | |
1532 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1533 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1534 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1535 | /* | |
1536 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1537 | */ | |
1538 | __wake_up_parent(tsk, parent); | |
1539 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1540 | } | |
1541 | ||
d5f70c00 ON |
1542 | static inline int may_ptrace_stop(void) |
1543 | { | |
1544 | if (!likely(current->ptrace & PT_PTRACED)) | |
1545 | return 0; | |
d5f70c00 ON |
1546 | /* |
1547 | * Are we in the middle of do_coredump? | |
1548 | * If so and our tracer is also part of the coredump stopping | |
1549 | * is a deadlock situation, and pointless because our tracer | |
1550 | * is dead so don't allow us to stop. | |
1551 | * If SIGKILL was already sent before the caller unlocked | |
1552 | * ->siglock we must see ->core_waiters != 0. Otherwise it | |
1553 | * is safe to enter schedule(). | |
1554 | */ | |
1555 | if (unlikely(current->mm->core_waiters) && | |
1556 | unlikely(current->mm == current->parent->mm)) | |
1557 | return 0; | |
1558 | ||
1559 | return 1; | |
1560 | } | |
1561 | ||
1a669c2f RM |
1562 | /* |
1563 | * Return nonzero if there is a SIGKILL that should be waking us up. | |
1564 | * Called with the siglock held. | |
1565 | */ | |
1566 | static int sigkill_pending(struct task_struct *tsk) | |
1567 | { | |
1568 | return ((sigismember(&tsk->pending.signal, SIGKILL) || | |
1569 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) && | |
1570 | !unlikely(sigismember(&tsk->blocked, SIGKILL))); | |
1571 | } | |
1572 | ||
1da177e4 LT |
1573 | /* |
1574 | * This must be called with current->sighand->siglock held. | |
1575 | * | |
1576 | * This should be the path for all ptrace stops. | |
1577 | * We always set current->last_siginfo while stopped here. | |
1578 | * That makes it a way to test a stopped process for | |
1579 | * being ptrace-stopped vs being job-control-stopped. | |
1580 | * | |
20686a30 ON |
1581 | * If we actually decide not to stop at all because the tracer |
1582 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1583 | */ |
20686a30 | 1584 | static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) |
1da177e4 | 1585 | { |
1a669c2f RM |
1586 | int killed = 0; |
1587 | ||
1588 | if (arch_ptrace_stop_needed(exit_code, info)) { | |
1589 | /* | |
1590 | * The arch code has something special to do before a | |
1591 | * ptrace stop. This is allowed to block, e.g. for faults | |
1592 | * on user stack pages. We can't keep the siglock while | |
1593 | * calling arch_ptrace_stop, so we must release it now. | |
1594 | * To preserve proper semantics, we must do this before | |
1595 | * any signal bookkeeping like checking group_stop_count. | |
1596 | * Meanwhile, a SIGKILL could come in before we retake the | |
1597 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1598 | * So after regaining the lock, we must check for SIGKILL. | |
1599 | */ | |
1600 | spin_unlock_irq(¤t->sighand->siglock); | |
1601 | arch_ptrace_stop(exit_code, info); | |
1602 | spin_lock_irq(¤t->sighand->siglock); | |
1603 | killed = sigkill_pending(current); | |
1604 | } | |
1605 | ||
1da177e4 LT |
1606 | /* |
1607 | * If there is a group stop in progress, | |
1608 | * we must participate in the bookkeeping. | |
1609 | */ | |
1610 | if (current->signal->group_stop_count > 0) | |
1611 | --current->signal->group_stop_count; | |
1612 | ||
1613 | current->last_siginfo = info; | |
1614 | current->exit_code = exit_code; | |
1615 | ||
1616 | /* Let the debugger run. */ | |
d9ae90ac | 1617 | __set_current_state(TASK_TRACED); |
1da177e4 LT |
1618 | spin_unlock_irq(¤t->sighand->siglock); |
1619 | read_lock(&tasklist_lock); | |
1a669c2f | 1620 | if (!unlikely(killed) && may_ptrace_stop()) { |
a1d5e21e | 1621 | do_notify_parent_cldstop(current, CLD_TRAPPED); |
1da177e4 LT |
1622 | read_unlock(&tasklist_lock); |
1623 | schedule(); | |
1624 | } else { | |
1625 | /* | |
1626 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1627 | * Don't drop the lock yet, another tracer may come. |
1da177e4 | 1628 | */ |
6405f7f4 | 1629 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1630 | if (clear_code) |
1631 | current->exit_code = 0; | |
6405f7f4 | 1632 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1633 | } |
1634 | ||
13b1c3d4 RM |
1635 | /* |
1636 | * While in TASK_TRACED, we were considered "frozen enough". | |
1637 | * Now that we woke up, it's crucial if we're supposed to be | |
1638 | * frozen that we freeze now before running anything substantial. | |
1639 | */ | |
1640 | try_to_freeze(); | |
1641 | ||
1da177e4 LT |
1642 | /* |
1643 | * We are back. Now reacquire the siglock before touching | |
1644 | * last_siginfo, so that we are sure to have synchronized with | |
1645 | * any signal-sending on another CPU that wants to examine it. | |
1646 | */ | |
1647 | spin_lock_irq(¤t->sighand->siglock); | |
1648 | current->last_siginfo = NULL; | |
1649 | ||
1650 | /* | |
1651 | * Queued signals ignored us while we were stopped for tracing. | |
1652 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1653 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1654 | */ |
b74d0deb | 1655 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1656 | } |
1657 | ||
1658 | void ptrace_notify(int exit_code) | |
1659 | { | |
1660 | siginfo_t info; | |
1661 | ||
1662 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1663 | ||
1664 | memset(&info, 0, sizeof info); | |
1665 | info.si_signo = SIGTRAP; | |
1666 | info.si_code = exit_code; | |
b488893a | 1667 | info.si_pid = task_pid_vnr(current); |
1da177e4 LT |
1668 | info.si_uid = current->uid; |
1669 | ||
1670 | /* Let the debugger run. */ | |
1671 | spin_lock_irq(¤t->sighand->siglock); | |
20686a30 | 1672 | ptrace_stop(exit_code, 1, &info); |
1da177e4 LT |
1673 | spin_unlock_irq(¤t->sighand->siglock); |
1674 | } | |
1675 | ||
1da177e4 LT |
1676 | static void |
1677 | finish_stop(int stop_count) | |
1678 | { | |
1679 | /* | |
1680 | * If there are no other threads in the group, or if there is | |
1681 | * a group stop in progress and we are the last to stop, | |
1682 | * report to the parent. When ptraced, every thread reports itself. | |
1683 | */ | |
a1d5e21e ON |
1684 | if (stop_count == 0 || (current->ptrace & PT_PTRACED)) { |
1685 | read_lock(&tasklist_lock); | |
1686 | do_notify_parent_cldstop(current, CLD_STOPPED); | |
1687 | read_unlock(&tasklist_lock); | |
1688 | } | |
bc505a47 | 1689 | |
3df494a3 RW |
1690 | do { |
1691 | schedule(); | |
1692 | } while (try_to_freeze()); | |
1da177e4 LT |
1693 | /* |
1694 | * Now we don't run again until continued. | |
1695 | */ | |
1696 | current->exit_code = 0; | |
1697 | } | |
1698 | ||
1699 | /* | |
1700 | * This performs the stopping for SIGSTOP and other stop signals. | |
1701 | * We have to stop all threads in the thread group. | |
1702 | * Returns nonzero if we've actually stopped and released the siglock. | |
1703 | * Returns zero if we didn't stop and still hold the siglock. | |
1704 | */ | |
a122b341 | 1705 | static int do_signal_stop(int signr) |
1da177e4 LT |
1706 | { |
1707 | struct signal_struct *sig = current->signal; | |
dac27f4a | 1708 | int stop_count; |
1da177e4 | 1709 | |
1da177e4 LT |
1710 | if (sig->group_stop_count > 0) { |
1711 | /* | |
1712 | * There is a group stop in progress. We don't need to | |
1713 | * start another one. | |
1714 | */ | |
1da177e4 | 1715 | stop_count = --sig->group_stop_count; |
dac27f4a | 1716 | } else { |
f558b7e4 ON |
1717 | struct task_struct *t; |
1718 | ||
ed5d2cac | 1719 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) || |
573cf9ad | 1720 | unlikely(signal_group_exit(sig))) |
f558b7e4 | 1721 | return 0; |
1da177e4 LT |
1722 | /* |
1723 | * There is no group stop already in progress. | |
a122b341 | 1724 | * We must initiate one now. |
1da177e4 | 1725 | */ |
a122b341 | 1726 | sig->group_exit_code = signr; |
1da177e4 | 1727 | |
a122b341 ON |
1728 | stop_count = 0; |
1729 | for (t = next_thread(current); t != current; t = next_thread(t)) | |
1da177e4 | 1730 | /* |
a122b341 ON |
1731 | * Setting state to TASK_STOPPED for a group |
1732 | * stop is always done with the siglock held, | |
1733 | * so this check has no races. | |
1da177e4 | 1734 | */ |
d12619b5 | 1735 | if (!(t->flags & PF_EXITING) && |
e1abb39c | 1736 | !task_is_stopped_or_traced(t)) { |
a122b341 ON |
1737 | stop_count++; |
1738 | signal_wake_up(t, 0); | |
1739 | } | |
1740 | sig->group_stop_count = stop_count; | |
1da177e4 LT |
1741 | } |
1742 | ||
dac27f4a ON |
1743 | if (stop_count == 0) |
1744 | sig->flags = SIGNAL_STOP_STOPPED; | |
1745 | current->exit_code = sig->group_exit_code; | |
1746 | __set_current_state(TASK_STOPPED); | |
1747 | ||
1748 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
1749 | finish_stop(stop_count); |
1750 | return 1; | |
1751 | } | |
1752 | ||
18c98b65 RM |
1753 | static int ptrace_signal(int signr, siginfo_t *info, |
1754 | struct pt_regs *regs, void *cookie) | |
1755 | { | |
1756 | if (!(current->ptrace & PT_PTRACED)) | |
1757 | return signr; | |
1758 | ||
1759 | ptrace_signal_deliver(regs, cookie); | |
1760 | ||
1761 | /* Let the debugger run. */ | |
1762 | ptrace_stop(signr, 0, info); | |
1763 | ||
1764 | /* We're back. Did the debugger cancel the sig? */ | |
1765 | signr = current->exit_code; | |
1766 | if (signr == 0) | |
1767 | return signr; | |
1768 | ||
1769 | current->exit_code = 0; | |
1770 | ||
1771 | /* Update the siginfo structure if the signal has | |
1772 | changed. If the debugger wanted something | |
1773 | specific in the siginfo structure then it should | |
1774 | have updated *info via PTRACE_SETSIGINFO. */ | |
1775 | if (signr != info->si_signo) { | |
1776 | info->si_signo = signr; | |
1777 | info->si_errno = 0; | |
1778 | info->si_code = SI_USER; | |
1779 | info->si_pid = task_pid_vnr(current->parent); | |
1780 | info->si_uid = current->parent->uid; | |
1781 | } | |
1782 | ||
1783 | /* If the (new) signal is now blocked, requeue it. */ | |
1784 | if (sigismember(¤t->blocked, signr)) { | |
1785 | specific_send_sig_info(signr, info, current); | |
1786 | signr = 0; | |
1787 | } | |
1788 | ||
1789 | return signr; | |
1790 | } | |
1791 | ||
1da177e4 LT |
1792 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
1793 | struct pt_regs *regs, void *cookie) | |
1794 | { | |
1795 | sigset_t *mask = ¤t->blocked; | |
1796 | int signr = 0; | |
1797 | ||
13b1c3d4 RM |
1798 | relock: |
1799 | /* | |
1800 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
1801 | * While in TASK_STOPPED, we were considered "frozen enough". | |
1802 | * Now that we woke up, it's crucial if we're supposed to be | |
1803 | * frozen that we freeze now before running anything substantial. | |
1804 | */ | |
fc558a74 RW |
1805 | try_to_freeze(); |
1806 | ||
1da177e4 LT |
1807 | spin_lock_irq(¤t->sighand->siglock); |
1808 | for (;;) { | |
1809 | struct k_sigaction *ka; | |
1810 | ||
1811 | if (unlikely(current->signal->group_stop_count > 0) && | |
f558b7e4 | 1812 | do_signal_stop(0)) |
1da177e4 LT |
1813 | goto relock; |
1814 | ||
1815 | signr = dequeue_signal(current, mask, info); | |
1816 | ||
1817 | if (!signr) | |
1818 | break; /* will return 0 */ | |
1819 | ||
18c98b65 RM |
1820 | if (signr != SIGKILL) { |
1821 | signr = ptrace_signal(signr, info, regs, cookie); | |
1822 | if (!signr) | |
1da177e4 | 1823 | continue; |
1da177e4 LT |
1824 | } |
1825 | ||
1826 | ka = ¤t->sighand->action[signr-1]; | |
1827 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ | |
1828 | continue; | |
1829 | if (ka->sa.sa_handler != SIG_DFL) { | |
1830 | /* Run the handler. */ | |
1831 | *return_ka = *ka; | |
1832 | ||
1833 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1834 | ka->sa.sa_handler = SIG_DFL; | |
1835 | ||
1836 | break; /* will return non-zero "signr" value */ | |
1837 | } | |
1838 | ||
1839 | /* | |
1840 | * Now we are doing the default action for this signal. | |
1841 | */ | |
1842 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1843 | continue; | |
1844 | ||
84d73786 | 1845 | /* |
0fbc26a6 | 1846 | * Global init gets no signals it doesn't want. |
84d73786 | 1847 | */ |
0fbc26a6 | 1848 | if (is_global_init(current)) |
1da177e4 LT |
1849 | continue; |
1850 | ||
1851 | if (sig_kernel_stop(signr)) { | |
1852 | /* | |
1853 | * The default action is to stop all threads in | |
1854 | * the thread group. The job control signals | |
1855 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1856 | * always works. Note that siglock needs to be | |
1857 | * dropped during the call to is_orphaned_pgrp() | |
1858 | * because of lock ordering with tasklist_lock. | |
1859 | * This allows an intervening SIGCONT to be posted. | |
1860 | * We need to check for that and bail out if necessary. | |
1861 | */ | |
1862 | if (signr != SIGSTOP) { | |
1863 | spin_unlock_irq(¤t->sighand->siglock); | |
1864 | ||
1865 | /* signals can be posted during this window */ | |
1866 | ||
3e7cd6c4 | 1867 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
1868 | goto relock; |
1869 | ||
1870 | spin_lock_irq(¤t->sighand->siglock); | |
1871 | } | |
1872 | ||
1873 | if (likely(do_signal_stop(signr))) { | |
1874 | /* It released the siglock. */ | |
1875 | goto relock; | |
1876 | } | |
1877 | ||
1878 | /* | |
1879 | * We didn't actually stop, due to a race | |
1880 | * with SIGCONT or something like that. | |
1881 | */ | |
1882 | continue; | |
1883 | } | |
1884 | ||
1885 | spin_unlock_irq(¤t->sighand->siglock); | |
1886 | ||
1887 | /* | |
1888 | * Anything else is fatal, maybe with a core dump. | |
1889 | */ | |
1890 | current->flags |= PF_SIGNALED; | |
45807a1d IM |
1891 | if ((signr != SIGKILL) && print_fatal_signals) |
1892 | print_fatal_signal(regs, signr); | |
1da177e4 LT |
1893 | if (sig_kernel_coredump(signr)) { |
1894 | /* | |
1895 | * If it was able to dump core, this kills all | |
1896 | * other threads in the group and synchronizes with | |
1897 | * their demise. If we lost the race with another | |
1898 | * thread getting here, it set group_exit_code | |
1899 | * first and our do_group_exit call below will use | |
1900 | * that value and ignore the one we pass it. | |
1901 | */ | |
1902 | do_coredump((long)signr, signr, regs); | |
1903 | } | |
1904 | ||
1905 | /* | |
1906 | * Death signals, no core dump. | |
1907 | */ | |
1908 | do_group_exit(signr); | |
1909 | /* NOTREACHED */ | |
1910 | } | |
1911 | spin_unlock_irq(¤t->sighand->siglock); | |
1912 | return signr; | |
1913 | } | |
1914 | ||
d12619b5 ON |
1915 | void exit_signals(struct task_struct *tsk) |
1916 | { | |
1917 | int group_stop = 0; | |
5dee1707 | 1918 | struct task_struct *t; |
d12619b5 | 1919 | |
5dee1707 ON |
1920 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
1921 | tsk->flags |= PF_EXITING; | |
1922 | return; | |
d12619b5 ON |
1923 | } |
1924 | ||
5dee1707 | 1925 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
1926 | /* |
1927 | * From now this task is not visible for group-wide signals, | |
1928 | * see wants_signal(), do_signal_stop(). | |
1929 | */ | |
1930 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
1931 | if (!signal_pending(tsk)) |
1932 | goto out; | |
1933 | ||
1934 | /* It could be that __group_complete_signal() choose us to | |
1935 | * notify about group-wide signal. Another thread should be | |
1936 | * woken now to take the signal since we will not. | |
1937 | */ | |
1938 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
1939 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
1940 | recalc_sigpending_and_wake(t); | |
1941 | ||
1942 | if (unlikely(tsk->signal->group_stop_count) && | |
1943 | !--tsk->signal->group_stop_count) { | |
1944 | tsk->signal->flags = SIGNAL_STOP_STOPPED; | |
1945 | group_stop = 1; | |
1946 | } | |
1947 | out: | |
d12619b5 ON |
1948 | spin_unlock_irq(&tsk->sighand->siglock); |
1949 | ||
1950 | if (unlikely(group_stop)) { | |
1951 | read_lock(&tasklist_lock); | |
1952 | do_notify_parent_cldstop(tsk, CLD_STOPPED); | |
1953 | read_unlock(&tasklist_lock); | |
1954 | } | |
1955 | } | |
1956 | ||
1da177e4 LT |
1957 | EXPORT_SYMBOL(recalc_sigpending); |
1958 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
1959 | EXPORT_SYMBOL(flush_signals); | |
1960 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
1961 | EXPORT_SYMBOL(kill_proc); |
1962 | EXPORT_SYMBOL(ptrace_notify); | |
1963 | EXPORT_SYMBOL(send_sig); | |
1964 | EXPORT_SYMBOL(send_sig_info); | |
1965 | EXPORT_SYMBOL(sigprocmask); | |
1966 | EXPORT_SYMBOL(block_all_signals); | |
1967 | EXPORT_SYMBOL(unblock_all_signals); | |
1968 | ||
1969 | ||
1970 | /* | |
1971 | * System call entry points. | |
1972 | */ | |
1973 | ||
1974 | asmlinkage long sys_restart_syscall(void) | |
1975 | { | |
1976 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
1977 | return restart->fn(restart); | |
1978 | } | |
1979 | ||
1980 | long do_no_restart_syscall(struct restart_block *param) | |
1981 | { | |
1982 | return -EINTR; | |
1983 | } | |
1984 | ||
1985 | /* | |
1986 | * We don't need to get the kernel lock - this is all local to this | |
1987 | * particular thread.. (and that's good, because this is _heavily_ | |
1988 | * used by various programs) | |
1989 | */ | |
1990 | ||
1991 | /* | |
1992 | * This is also useful for kernel threads that want to temporarily | |
1993 | * (or permanently) block certain signals. | |
1994 | * | |
1995 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
1996 | * interface happily blocks "unblockable" signals like SIGKILL | |
1997 | * and friends. | |
1998 | */ | |
1999 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2000 | { | |
2001 | int error; | |
1da177e4 LT |
2002 | |
2003 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
2004 | if (oldset) |
2005 | *oldset = current->blocked; | |
2006 | ||
1da177e4 LT |
2007 | error = 0; |
2008 | switch (how) { | |
2009 | case SIG_BLOCK: | |
2010 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2011 | break; | |
2012 | case SIG_UNBLOCK: | |
2013 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2014 | break; | |
2015 | case SIG_SETMASK: | |
2016 | current->blocked = *set; | |
2017 | break; | |
2018 | default: | |
2019 | error = -EINVAL; | |
2020 | } | |
2021 | recalc_sigpending(); | |
2022 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 2023 | |
1da177e4 LT |
2024 | return error; |
2025 | } | |
2026 | ||
2027 | asmlinkage long | |
2028 | sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize) | |
2029 | { | |
2030 | int error = -EINVAL; | |
2031 | sigset_t old_set, new_set; | |
2032 | ||
2033 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2034 | if (sigsetsize != sizeof(sigset_t)) | |
2035 | goto out; | |
2036 | ||
2037 | if (set) { | |
2038 | error = -EFAULT; | |
2039 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2040 | goto out; | |
2041 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2042 | ||
2043 | error = sigprocmask(how, &new_set, &old_set); | |
2044 | if (error) | |
2045 | goto out; | |
2046 | if (oset) | |
2047 | goto set_old; | |
2048 | } else if (oset) { | |
2049 | spin_lock_irq(¤t->sighand->siglock); | |
2050 | old_set = current->blocked; | |
2051 | spin_unlock_irq(¤t->sighand->siglock); | |
2052 | ||
2053 | set_old: | |
2054 | error = -EFAULT; | |
2055 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2056 | goto out; | |
2057 | } | |
2058 | error = 0; | |
2059 | out: | |
2060 | return error; | |
2061 | } | |
2062 | ||
2063 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2064 | { | |
2065 | long error = -EINVAL; | |
2066 | sigset_t pending; | |
2067 | ||
2068 | if (sigsetsize > sizeof(sigset_t)) | |
2069 | goto out; | |
2070 | ||
2071 | spin_lock_irq(¤t->sighand->siglock); | |
2072 | sigorsets(&pending, ¤t->pending.signal, | |
2073 | ¤t->signal->shared_pending.signal); | |
2074 | spin_unlock_irq(¤t->sighand->siglock); | |
2075 | ||
2076 | /* Outside the lock because only this thread touches it. */ | |
2077 | sigandsets(&pending, ¤t->blocked, &pending); | |
2078 | ||
2079 | error = -EFAULT; | |
2080 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2081 | error = 0; | |
2082 | ||
2083 | out: | |
2084 | return error; | |
2085 | } | |
2086 | ||
2087 | asmlinkage long | |
2088 | sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize) | |
2089 | { | |
2090 | return do_sigpending(set, sigsetsize); | |
2091 | } | |
2092 | ||
2093 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2094 | ||
2095 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2096 | { | |
2097 | int err; | |
2098 | ||
2099 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2100 | return -EFAULT; | |
2101 | if (from->si_code < 0) | |
2102 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2103 | ? -EFAULT : 0; | |
2104 | /* | |
2105 | * If you change siginfo_t structure, please be sure | |
2106 | * this code is fixed accordingly. | |
fba2afaa DL |
2107 | * Please remember to update the signalfd_copyinfo() function |
2108 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2109 | * It should never copy any pad contained in the structure |
2110 | * to avoid security leaks, but must copy the generic | |
2111 | * 3 ints plus the relevant union member. | |
2112 | */ | |
2113 | err = __put_user(from->si_signo, &to->si_signo); | |
2114 | err |= __put_user(from->si_errno, &to->si_errno); | |
2115 | err |= __put_user((short)from->si_code, &to->si_code); | |
2116 | switch (from->si_code & __SI_MASK) { | |
2117 | case __SI_KILL: | |
2118 | err |= __put_user(from->si_pid, &to->si_pid); | |
2119 | err |= __put_user(from->si_uid, &to->si_uid); | |
2120 | break; | |
2121 | case __SI_TIMER: | |
2122 | err |= __put_user(from->si_tid, &to->si_tid); | |
2123 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2124 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2125 | break; | |
2126 | case __SI_POLL: | |
2127 | err |= __put_user(from->si_band, &to->si_band); | |
2128 | err |= __put_user(from->si_fd, &to->si_fd); | |
2129 | break; | |
2130 | case __SI_FAULT: | |
2131 | err |= __put_user(from->si_addr, &to->si_addr); | |
2132 | #ifdef __ARCH_SI_TRAPNO | |
2133 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
2134 | #endif | |
2135 | break; | |
2136 | case __SI_CHLD: | |
2137 | err |= __put_user(from->si_pid, &to->si_pid); | |
2138 | err |= __put_user(from->si_uid, &to->si_uid); | |
2139 | err |= __put_user(from->si_status, &to->si_status); | |
2140 | err |= __put_user(from->si_utime, &to->si_utime); | |
2141 | err |= __put_user(from->si_stime, &to->si_stime); | |
2142 | break; | |
2143 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2144 | case __SI_MESGQ: /* But this is */ | |
2145 | err |= __put_user(from->si_pid, &to->si_pid); | |
2146 | err |= __put_user(from->si_uid, &to->si_uid); | |
2147 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2148 | break; | |
2149 | default: /* this is just in case for now ... */ | |
2150 | err |= __put_user(from->si_pid, &to->si_pid); | |
2151 | err |= __put_user(from->si_uid, &to->si_uid); | |
2152 | break; | |
2153 | } | |
2154 | return err; | |
2155 | } | |
2156 | ||
2157 | #endif | |
2158 | ||
2159 | asmlinkage long | |
2160 | sys_rt_sigtimedwait(const sigset_t __user *uthese, | |
2161 | siginfo_t __user *uinfo, | |
2162 | const struct timespec __user *uts, | |
2163 | size_t sigsetsize) | |
2164 | { | |
2165 | int ret, sig; | |
2166 | sigset_t these; | |
2167 | struct timespec ts; | |
2168 | siginfo_t info; | |
2169 | long timeout = 0; | |
2170 | ||
2171 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2172 | if (sigsetsize != sizeof(sigset_t)) | |
2173 | return -EINVAL; | |
2174 | ||
2175 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2176 | return -EFAULT; | |
2177 | ||
2178 | /* | |
2179 | * Invert the set of allowed signals to get those we | |
2180 | * want to block. | |
2181 | */ | |
2182 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2183 | signotset(&these); | |
2184 | ||
2185 | if (uts) { | |
2186 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2187 | return -EFAULT; | |
2188 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2189 | || ts.tv_sec < 0) | |
2190 | return -EINVAL; | |
2191 | } | |
2192 | ||
2193 | spin_lock_irq(¤t->sighand->siglock); | |
2194 | sig = dequeue_signal(current, &these, &info); | |
2195 | if (!sig) { | |
2196 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2197 | if (uts) | |
2198 | timeout = (timespec_to_jiffies(&ts) | |
2199 | + (ts.tv_sec || ts.tv_nsec)); | |
2200 | ||
2201 | if (timeout) { | |
2202 | /* None ready -- temporarily unblock those we're | |
2203 | * interested while we are sleeping in so that we'll | |
2204 | * be awakened when they arrive. */ | |
2205 | current->real_blocked = current->blocked; | |
2206 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2207 | recalc_sigpending(); | |
2208 | spin_unlock_irq(¤t->sighand->siglock); | |
2209 | ||
75bcc8c5 | 2210 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2211 | |
1da177e4 LT |
2212 | spin_lock_irq(¤t->sighand->siglock); |
2213 | sig = dequeue_signal(current, &these, &info); | |
2214 | current->blocked = current->real_blocked; | |
2215 | siginitset(¤t->real_blocked, 0); | |
2216 | recalc_sigpending(); | |
2217 | } | |
2218 | } | |
2219 | spin_unlock_irq(¤t->sighand->siglock); | |
2220 | ||
2221 | if (sig) { | |
2222 | ret = sig; | |
2223 | if (uinfo) { | |
2224 | if (copy_siginfo_to_user(uinfo, &info)) | |
2225 | ret = -EFAULT; | |
2226 | } | |
2227 | } else { | |
2228 | ret = -EAGAIN; | |
2229 | if (timeout) | |
2230 | ret = -EINTR; | |
2231 | } | |
2232 | ||
2233 | return ret; | |
2234 | } | |
2235 | ||
2236 | asmlinkage long | |
2237 | sys_kill(int pid, int sig) | |
2238 | { | |
2239 | struct siginfo info; | |
2240 | ||
2241 | info.si_signo = sig; | |
2242 | info.si_errno = 0; | |
2243 | info.si_code = SI_USER; | |
b488893a | 2244 | info.si_pid = task_tgid_vnr(current); |
1da177e4 LT |
2245 | info.si_uid = current->uid; |
2246 | ||
2247 | return kill_something_info(sig, &info, pid); | |
2248 | } | |
2249 | ||
6dd69f10 | 2250 | static int do_tkill(int tgid, int pid, int sig) |
1da177e4 | 2251 | { |
1da177e4 | 2252 | int error; |
6dd69f10 | 2253 | struct siginfo info; |
1da177e4 LT |
2254 | struct task_struct *p; |
2255 | ||
6dd69f10 | 2256 | error = -ESRCH; |
1da177e4 LT |
2257 | info.si_signo = sig; |
2258 | info.si_errno = 0; | |
2259 | info.si_code = SI_TKILL; | |
b488893a | 2260 | info.si_pid = task_tgid_vnr(current); |
1da177e4 LT |
2261 | info.si_uid = current->uid; |
2262 | ||
2263 | read_lock(&tasklist_lock); | |
228ebcbe | 2264 | p = find_task_by_vpid(pid); |
b488893a | 2265 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
1da177e4 LT |
2266 | error = check_kill_permission(sig, &info, p); |
2267 | /* | |
2268 | * The null signal is a permissions and process existence | |
2269 | * probe. No signal is actually delivered. | |
2270 | */ | |
2271 | if (!error && sig && p->sighand) { | |
2272 | spin_lock_irq(&p->sighand->siglock); | |
2273 | handle_stop_signal(sig, p); | |
2274 | error = specific_send_sig_info(sig, &info, p); | |
2275 | spin_unlock_irq(&p->sighand->siglock); | |
2276 | } | |
2277 | } | |
2278 | read_unlock(&tasklist_lock); | |
6dd69f10 | 2279 | |
1da177e4 LT |
2280 | return error; |
2281 | } | |
2282 | ||
6dd69f10 VL |
2283 | /** |
2284 | * sys_tgkill - send signal to one specific thread | |
2285 | * @tgid: the thread group ID of the thread | |
2286 | * @pid: the PID of the thread | |
2287 | * @sig: signal to be sent | |
2288 | * | |
72fd4a35 | 2289 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2290 | * exists but it's not belonging to the target process anymore. This |
2291 | * method solves the problem of threads exiting and PIDs getting reused. | |
2292 | */ | |
2293 | asmlinkage long sys_tgkill(int tgid, int pid, int sig) | |
2294 | { | |
2295 | /* This is only valid for single tasks */ | |
2296 | if (pid <= 0 || tgid <= 0) | |
2297 | return -EINVAL; | |
2298 | ||
2299 | return do_tkill(tgid, pid, sig); | |
2300 | } | |
2301 | ||
1da177e4 LT |
2302 | /* |
2303 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2304 | */ | |
2305 | asmlinkage long | |
2306 | sys_tkill(int pid, int sig) | |
2307 | { | |
1da177e4 LT |
2308 | /* This is only valid for single tasks */ |
2309 | if (pid <= 0) | |
2310 | return -EINVAL; | |
2311 | ||
6dd69f10 | 2312 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2313 | } |
2314 | ||
2315 | asmlinkage long | |
2316 | sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) | |
2317 | { | |
2318 | siginfo_t info; | |
2319 | ||
2320 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2321 | return -EFAULT; | |
2322 | ||
2323 | /* Not even root can pretend to send signals from the kernel. | |
2324 | Nor can they impersonate a kill(), which adds source info. */ | |
2325 | if (info.si_code >= 0) | |
2326 | return -EPERM; | |
2327 | info.si_signo = sig; | |
2328 | ||
2329 | /* POSIX.1b doesn't mention process groups. */ | |
2330 | return kill_proc_info(sig, &info, pid); | |
2331 | } | |
2332 | ||
88531f72 | 2333 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 LT |
2334 | { |
2335 | struct k_sigaction *k; | |
71fabd5e | 2336 | sigset_t mask; |
1da177e4 | 2337 | |
7ed20e1a | 2338 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2339 | return -EINVAL; |
2340 | ||
2341 | k = ¤t->sighand->action[sig-1]; | |
2342 | ||
2343 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2344 | if (oact) |
2345 | *oact = *k; | |
2346 | ||
2347 | if (act) { | |
9ac95f2f ON |
2348 | sigdelsetmask(&act->sa.sa_mask, |
2349 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2350 | *k = *act; |
1da177e4 LT |
2351 | /* |
2352 | * POSIX 3.3.1.3: | |
2353 | * "Setting a signal action to SIG_IGN for a signal that is | |
2354 | * pending shall cause the pending signal to be discarded, | |
2355 | * whether or not it is blocked." | |
2356 | * | |
2357 | * "Setting a signal action to SIG_DFL for a signal that is | |
2358 | * pending and whose default action is to ignore the signal | |
2359 | * (for example, SIGCHLD), shall cause the pending signal to | |
2360 | * be discarded, whether or not it is blocked" | |
2361 | */ | |
2362 | if (act->sa.sa_handler == SIG_IGN || | |
88531f72 | 2363 | (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) { |
1da177e4 | 2364 | struct task_struct *t = current; |
71fabd5e GA |
2365 | sigemptyset(&mask); |
2366 | sigaddset(&mask, sig); | |
2367 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2368 | do { |
71fabd5e | 2369 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2370 | t = next_thread(t); |
2371 | } while (t != current); | |
1da177e4 | 2372 | } |
1da177e4 LT |
2373 | } |
2374 | ||
2375 | spin_unlock_irq(¤t->sighand->siglock); | |
2376 | return 0; | |
2377 | } | |
2378 | ||
2379 | int | |
2380 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2381 | { | |
2382 | stack_t oss; | |
2383 | int error; | |
2384 | ||
2385 | if (uoss) { | |
2386 | oss.ss_sp = (void __user *) current->sas_ss_sp; | |
2387 | oss.ss_size = current->sas_ss_size; | |
2388 | oss.ss_flags = sas_ss_flags(sp); | |
2389 | } | |
2390 | ||
2391 | if (uss) { | |
2392 | void __user *ss_sp; | |
2393 | size_t ss_size; | |
2394 | int ss_flags; | |
2395 | ||
2396 | error = -EFAULT; | |
2397 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss)) | |
2398 | || __get_user(ss_sp, &uss->ss_sp) | |
2399 | || __get_user(ss_flags, &uss->ss_flags) | |
2400 | || __get_user(ss_size, &uss->ss_size)) | |
2401 | goto out; | |
2402 | ||
2403 | error = -EPERM; | |
2404 | if (on_sig_stack(sp)) | |
2405 | goto out; | |
2406 | ||
2407 | error = -EINVAL; | |
2408 | /* | |
2409 | * | |
2410 | * Note - this code used to test ss_flags incorrectly | |
2411 | * old code may have been written using ss_flags==0 | |
2412 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2413 | * way that worked) - this fix preserves that older | |
2414 | * mechanism | |
2415 | */ | |
2416 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2417 | goto out; | |
2418 | ||
2419 | if (ss_flags == SS_DISABLE) { | |
2420 | ss_size = 0; | |
2421 | ss_sp = NULL; | |
2422 | } else { | |
2423 | error = -ENOMEM; | |
2424 | if (ss_size < MINSIGSTKSZ) | |
2425 | goto out; | |
2426 | } | |
2427 | ||
2428 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2429 | current->sas_ss_size = ss_size; | |
2430 | } | |
2431 | ||
2432 | if (uoss) { | |
2433 | error = -EFAULT; | |
2434 | if (copy_to_user(uoss, &oss, sizeof(oss))) | |
2435 | goto out; | |
2436 | } | |
2437 | ||
2438 | error = 0; | |
2439 | out: | |
2440 | return error; | |
2441 | } | |
2442 | ||
2443 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2444 | ||
2445 | asmlinkage long | |
2446 | sys_sigpending(old_sigset_t __user *set) | |
2447 | { | |
2448 | return do_sigpending(set, sizeof(*set)); | |
2449 | } | |
2450 | ||
2451 | #endif | |
2452 | ||
2453 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2454 | /* Some platforms have their own version with special arguments others | |
2455 | support only sys_rt_sigprocmask. */ | |
2456 | ||
2457 | asmlinkage long | |
2458 | sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset) | |
2459 | { | |
2460 | int error; | |
2461 | old_sigset_t old_set, new_set; | |
2462 | ||
2463 | if (set) { | |
2464 | error = -EFAULT; | |
2465 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2466 | goto out; | |
2467 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2468 | ||
2469 | spin_lock_irq(¤t->sighand->siglock); | |
2470 | old_set = current->blocked.sig[0]; | |
2471 | ||
2472 | error = 0; | |
2473 | switch (how) { | |
2474 | default: | |
2475 | error = -EINVAL; | |
2476 | break; | |
2477 | case SIG_BLOCK: | |
2478 | sigaddsetmask(¤t->blocked, new_set); | |
2479 | break; | |
2480 | case SIG_UNBLOCK: | |
2481 | sigdelsetmask(¤t->blocked, new_set); | |
2482 | break; | |
2483 | case SIG_SETMASK: | |
2484 | current->blocked.sig[0] = new_set; | |
2485 | break; | |
2486 | } | |
2487 | ||
2488 | recalc_sigpending(); | |
2489 | spin_unlock_irq(¤t->sighand->siglock); | |
2490 | if (error) | |
2491 | goto out; | |
2492 | if (oset) | |
2493 | goto set_old; | |
2494 | } else if (oset) { | |
2495 | old_set = current->blocked.sig[0]; | |
2496 | set_old: | |
2497 | error = -EFAULT; | |
2498 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2499 | goto out; | |
2500 | } | |
2501 | error = 0; | |
2502 | out: | |
2503 | return error; | |
2504 | } | |
2505 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2506 | ||
2507 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
2508 | asmlinkage long | |
2509 | sys_rt_sigaction(int sig, | |
2510 | const struct sigaction __user *act, | |
2511 | struct sigaction __user *oact, | |
2512 | size_t sigsetsize) | |
2513 | { | |
2514 | struct k_sigaction new_sa, old_sa; | |
2515 | int ret = -EINVAL; | |
2516 | ||
2517 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2518 | if (sigsetsize != sizeof(sigset_t)) | |
2519 | goto out; | |
2520 | ||
2521 | if (act) { | |
2522 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2523 | return -EFAULT; | |
2524 | } | |
2525 | ||
2526 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2527 | ||
2528 | if (!ret && oact) { | |
2529 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2530 | return -EFAULT; | |
2531 | } | |
2532 | out: | |
2533 | return ret; | |
2534 | } | |
2535 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2536 | ||
2537 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2538 | ||
2539 | /* | |
2540 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2541 | */ | |
2542 | asmlinkage long | |
2543 | sys_sgetmask(void) | |
2544 | { | |
2545 | /* SMP safe */ | |
2546 | return current->blocked.sig[0]; | |
2547 | } | |
2548 | ||
2549 | asmlinkage long | |
2550 | sys_ssetmask(int newmask) | |
2551 | { | |
2552 | int old; | |
2553 | ||
2554 | spin_lock_irq(¤t->sighand->siglock); | |
2555 | old = current->blocked.sig[0]; | |
2556 | ||
2557 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2558 | sigmask(SIGSTOP))); | |
2559 | recalc_sigpending(); | |
2560 | spin_unlock_irq(¤t->sighand->siglock); | |
2561 | ||
2562 | return old; | |
2563 | } | |
2564 | #endif /* __ARCH_WANT_SGETMASK */ | |
2565 | ||
2566 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2567 | /* | |
2568 | * For backwards compatibility. Functionality superseded by sigaction. | |
2569 | */ | |
2570 | asmlinkage unsigned long | |
2571 | sys_signal(int sig, __sighandler_t handler) | |
2572 | { | |
2573 | struct k_sigaction new_sa, old_sa; | |
2574 | int ret; | |
2575 | ||
2576 | new_sa.sa.sa_handler = handler; | |
2577 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2578 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2579 | |
2580 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2581 | ||
2582 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2583 | } | |
2584 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2585 | ||
2586 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2587 | ||
2588 | asmlinkage long | |
2589 | sys_pause(void) | |
2590 | { | |
2591 | current->state = TASK_INTERRUPTIBLE; | |
2592 | schedule(); | |
2593 | return -ERESTARTNOHAND; | |
2594 | } | |
2595 | ||
2596 | #endif | |
2597 | ||
150256d8 DW |
2598 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
2599 | asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize) | |
2600 | { | |
2601 | sigset_t newset; | |
2602 | ||
2603 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2604 | if (sigsetsize != sizeof(sigset_t)) | |
2605 | return -EINVAL; | |
2606 | ||
2607 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2608 | return -EFAULT; | |
2609 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2610 | ||
2611 | spin_lock_irq(¤t->sighand->siglock); | |
2612 | current->saved_sigmask = current->blocked; | |
2613 | current->blocked = newset; | |
2614 | recalc_sigpending(); | |
2615 | spin_unlock_irq(¤t->sighand->siglock); | |
2616 | ||
2617 | current->state = TASK_INTERRUPTIBLE; | |
2618 | schedule(); | |
2619 | set_thread_flag(TIF_RESTORE_SIGMASK); | |
2620 | return -ERESTARTNOHAND; | |
2621 | } | |
2622 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2623 | ||
f269fdd1 DH |
2624 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2625 | { | |
2626 | return NULL; | |
2627 | } | |
2628 | ||
1da177e4 LT |
2629 | void __init signals_init(void) |
2630 | { | |
0a31bd5f | 2631 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2632 | } |