Commit | Line | Data |
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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 | |
93585eea PE |
42 | static int __sig_ignored(struct task_struct *t, int sig) |
43 | { | |
44 | void __user *handler; | |
45 | ||
46 | /* Is it explicitly or implicitly ignored? */ | |
47 | ||
48 | handler = t->sighand->action[sig - 1].sa.sa_handler; | |
49 | return handler == SIG_IGN || | |
50 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
51 | } | |
1da177e4 LT |
52 | |
53 | static int sig_ignored(struct task_struct *t, int sig) | |
54 | { | |
1da177e4 LT |
55 | /* |
56 | * Tracers always want to know about signals.. | |
57 | */ | |
58 | if (t->ptrace & PT_PTRACED) | |
59 | return 0; | |
60 | ||
61 | /* | |
62 | * Blocked signals are never ignored, since the | |
63 | * signal handler may change by the time it is | |
64 | * unblocked. | |
65 | */ | |
325d22df | 66 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
67 | return 0; |
68 | ||
93585eea | 69 | return __sig_ignored(t, sig); |
1da177e4 LT |
70 | } |
71 | ||
72 | /* | |
73 | * Re-calculate pending state from the set of locally pending | |
74 | * signals, globally pending signals, and blocked signals. | |
75 | */ | |
76 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
77 | { | |
78 | unsigned long ready; | |
79 | long i; | |
80 | ||
81 | switch (_NSIG_WORDS) { | |
82 | default: | |
83 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
84 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
85 | break; | |
86 | ||
87 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
88 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
89 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
90 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
91 | break; | |
92 | ||
93 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
94 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
95 | break; | |
96 | ||
97 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
98 | } | |
99 | return ready != 0; | |
100 | } | |
101 | ||
102 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
103 | ||
7bb44ade | 104 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 LT |
105 | { |
106 | if (t->signal->group_stop_count > 0 || | |
107 | PENDING(&t->pending, &t->blocked) || | |
7bb44ade | 108 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 109 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
110 | return 1; |
111 | } | |
b74d0deb RM |
112 | /* |
113 | * We must never clear the flag in another thread, or in current | |
114 | * when it's possible the current syscall is returning -ERESTART*. | |
115 | * So we don't clear it here, and only callers who know they should do. | |
116 | */ | |
7bb44ade RM |
117 | return 0; |
118 | } | |
119 | ||
120 | /* | |
121 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
122 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
123 | */ | |
124 | void recalc_sigpending_and_wake(struct task_struct *t) | |
125 | { | |
126 | if (recalc_sigpending_tsk(t)) | |
127 | signal_wake_up(t, 0); | |
1da177e4 LT |
128 | } |
129 | ||
130 | void recalc_sigpending(void) | |
131 | { | |
cc5f916e | 132 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
133 | clear_thread_flag(TIF_SIGPENDING); |
134 | ||
1da177e4 LT |
135 | } |
136 | ||
137 | /* Given the mask, find the first available signal that should be serviced. */ | |
138 | ||
fba2afaa | 139 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
140 | { |
141 | unsigned long i, *s, *m, x; | |
142 | int sig = 0; | |
143 | ||
144 | s = pending->signal.sig; | |
145 | m = mask->sig; | |
146 | switch (_NSIG_WORDS) { | |
147 | default: | |
148 | for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m) | |
149 | if ((x = *s &~ *m) != 0) { | |
150 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
151 | break; | |
152 | } | |
153 | break; | |
154 | ||
155 | case 2: if ((x = s[0] &~ m[0]) != 0) | |
156 | sig = 1; | |
157 | else if ((x = s[1] &~ m[1]) != 0) | |
158 | sig = _NSIG_BPW + 1; | |
159 | else | |
160 | break; | |
161 | sig += ffz(~x); | |
162 | break; | |
163 | ||
164 | case 1: if ((x = *s &~ *m) != 0) | |
165 | sig = ffz(~x) + 1; | |
166 | break; | |
167 | } | |
168 | ||
169 | return sig; | |
170 | } | |
171 | ||
dd0fc66f | 172 | static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, |
1da177e4 LT |
173 | int override_rlimit) |
174 | { | |
175 | struct sigqueue *q = NULL; | |
10b1fbdb | 176 | struct user_struct *user; |
1da177e4 | 177 | |
10b1fbdb LT |
178 | /* |
179 | * In order to avoid problems with "switch_user()", we want to make | |
180 | * sure that the compiler doesn't re-load "t->user" | |
181 | */ | |
182 | user = t->user; | |
183 | barrier(); | |
184 | atomic_inc(&user->sigpending); | |
1da177e4 | 185 | if (override_rlimit || |
10b1fbdb | 186 | atomic_read(&user->sigpending) <= |
1da177e4 LT |
187 | t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) |
188 | q = kmem_cache_alloc(sigqueue_cachep, flags); | |
189 | if (unlikely(q == NULL)) { | |
10b1fbdb | 190 | atomic_dec(&user->sigpending); |
1da177e4 LT |
191 | } else { |
192 | INIT_LIST_HEAD(&q->list); | |
193 | q->flags = 0; | |
10b1fbdb | 194 | q->user = get_uid(user); |
1da177e4 LT |
195 | } |
196 | return(q); | |
197 | } | |
198 | ||
514a01b8 | 199 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
200 | { |
201 | if (q->flags & SIGQUEUE_PREALLOC) | |
202 | return; | |
203 | atomic_dec(&q->user->sigpending); | |
204 | free_uid(q->user); | |
205 | kmem_cache_free(sigqueue_cachep, q); | |
206 | } | |
207 | ||
6a14c5c9 | 208 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
209 | { |
210 | struct sigqueue *q; | |
211 | ||
212 | sigemptyset(&queue->signal); | |
213 | while (!list_empty(&queue->list)) { | |
214 | q = list_entry(queue->list.next, struct sigqueue , list); | |
215 | list_del_init(&q->list); | |
216 | __sigqueue_free(q); | |
217 | } | |
218 | } | |
219 | ||
220 | /* | |
221 | * Flush all pending signals for a task. | |
222 | */ | |
c81addc9 | 223 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
224 | { |
225 | unsigned long flags; | |
226 | ||
227 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
f5264481 | 228 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 LT |
229 | flush_sigqueue(&t->pending); |
230 | flush_sigqueue(&t->signal->shared_pending); | |
231 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
232 | } | |
233 | ||
10ab825b ON |
234 | void ignore_signals(struct task_struct *t) |
235 | { | |
236 | int i; | |
237 | ||
238 | for (i = 0; i < _NSIG; ++i) | |
239 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
240 | ||
241 | flush_signals(t); | |
242 | } | |
243 | ||
1da177e4 LT |
244 | /* |
245 | * Flush all handlers for a task. | |
246 | */ | |
247 | ||
248 | void | |
249 | flush_signal_handlers(struct task_struct *t, int force_default) | |
250 | { | |
251 | int i; | |
252 | struct k_sigaction *ka = &t->sighand->action[0]; | |
253 | for (i = _NSIG ; i != 0 ; i--) { | |
254 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
255 | ka->sa.sa_handler = SIG_DFL; | |
256 | ka->sa.sa_flags = 0; | |
257 | sigemptyset(&ka->sa.sa_mask); | |
258 | ka++; | |
259 | } | |
260 | } | |
261 | ||
abd4f750 MAS |
262 | int unhandled_signal(struct task_struct *tsk, int sig) |
263 | { | |
b460cbc5 | 264 | if (is_global_init(tsk)) |
abd4f750 MAS |
265 | return 1; |
266 | if (tsk->ptrace & PT_PTRACED) | |
267 | return 0; | |
268 | return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) || | |
269 | (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL); | |
270 | } | |
271 | ||
1da177e4 LT |
272 | |
273 | /* Notify the system that a driver wants to block all signals for this | |
274 | * process, and wants to be notified if any signals at all were to be | |
275 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
276 | * signal will be acted upon after all. If the notifier routine returns 0, | |
277 | * then then signal will be blocked. Only one block per process is | |
278 | * allowed. priv is a pointer to private data that the notifier routine | |
279 | * can use to determine if the signal should be blocked or not. */ | |
280 | ||
281 | void | |
282 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
283 | { | |
284 | unsigned long flags; | |
285 | ||
286 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
287 | current->notifier_mask = mask; | |
288 | current->notifier_data = priv; | |
289 | current->notifier = notifier; | |
290 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
291 | } | |
292 | ||
293 | /* Notify the system that blocking has ended. */ | |
294 | ||
295 | void | |
296 | unblock_all_signals(void) | |
297 | { | |
298 | unsigned long flags; | |
299 | ||
300 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
301 | current->notifier = NULL; | |
302 | current->notifier_data = NULL; | |
303 | recalc_sigpending(); | |
304 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
305 | } | |
306 | ||
858119e1 | 307 | static int collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
308 | { |
309 | struct sigqueue *q, *first = NULL; | |
310 | int still_pending = 0; | |
311 | ||
312 | if (unlikely(!sigismember(&list->signal, sig))) | |
313 | return 0; | |
314 | ||
315 | /* | |
316 | * Collect the siginfo appropriate to this signal. Check if | |
317 | * there is another siginfo for the same signal. | |
318 | */ | |
319 | list_for_each_entry(q, &list->list, list) { | |
320 | if (q->info.si_signo == sig) { | |
321 | if (first) { | |
322 | still_pending = 1; | |
323 | break; | |
324 | } | |
325 | first = q; | |
326 | } | |
327 | } | |
328 | if (first) { | |
329 | list_del_init(&first->list); | |
330 | copy_siginfo(info, &first->info); | |
331 | __sigqueue_free(first); | |
332 | if (!still_pending) | |
333 | sigdelset(&list->signal, sig); | |
334 | } else { | |
335 | ||
336 | /* Ok, it wasn't in the queue. This must be | |
337 | a fast-pathed signal or we must have been | |
338 | out of queue space. So zero out the info. | |
339 | */ | |
340 | sigdelset(&list->signal, sig); | |
341 | info->si_signo = sig; | |
342 | info->si_errno = 0; | |
343 | info->si_code = 0; | |
344 | info->si_pid = 0; | |
345 | info->si_uid = 0; | |
346 | } | |
347 | return 1; | |
348 | } | |
349 | ||
350 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
351 | siginfo_t *info) | |
352 | { | |
27d91e07 | 353 | int sig = next_signal(pending, mask); |
1da177e4 | 354 | |
1da177e4 LT |
355 | if (sig) { |
356 | if (current->notifier) { | |
357 | if (sigismember(current->notifier_mask, sig)) { | |
358 | if (!(current->notifier)(current->notifier_data)) { | |
359 | clear_thread_flag(TIF_SIGPENDING); | |
360 | return 0; | |
361 | } | |
362 | } | |
363 | } | |
364 | ||
365 | if (!collect_signal(sig, pending, info)) | |
366 | sig = 0; | |
1da177e4 | 367 | } |
1da177e4 LT |
368 | |
369 | return sig; | |
370 | } | |
371 | ||
372 | /* | |
373 | * Dequeue a signal and return the element to the caller, which is | |
374 | * expected to free it. | |
375 | * | |
376 | * All callers have to hold the siglock. | |
377 | */ | |
378 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
379 | { | |
c5363d03 | 380 | int signr; |
caec4e8d BH |
381 | |
382 | /* We only dequeue private signals from ourselves, we don't let | |
383 | * signalfd steal them | |
384 | */ | |
b8fceee1 | 385 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 386 | if (!signr) { |
1da177e4 LT |
387 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
388 | mask, info); | |
8bfd9a7a TG |
389 | /* |
390 | * itimer signal ? | |
391 | * | |
392 | * itimers are process shared and we restart periodic | |
393 | * itimers in the signal delivery path to prevent DoS | |
394 | * attacks in the high resolution timer case. This is | |
395 | * compliant with the old way of self restarting | |
396 | * itimers, as the SIGALRM is a legacy signal and only | |
397 | * queued once. Changing the restart behaviour to | |
398 | * restart the timer in the signal dequeue path is | |
399 | * reducing the timer noise on heavy loaded !highres | |
400 | * systems too. | |
401 | */ | |
402 | if (unlikely(signr == SIGALRM)) { | |
403 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
404 | ||
405 | if (!hrtimer_is_queued(tmr) && | |
406 | tsk->signal->it_real_incr.tv64 != 0) { | |
407 | hrtimer_forward(tmr, tmr->base->get_time(), | |
408 | tsk->signal->it_real_incr); | |
409 | hrtimer_restart(tmr); | |
410 | } | |
411 | } | |
412 | } | |
c5363d03 | 413 | |
b8fceee1 | 414 | recalc_sigpending(); |
c5363d03 PE |
415 | if (!signr) |
416 | return 0; | |
417 | ||
418 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
419 | /* |
420 | * Set a marker that we have dequeued a stop signal. Our | |
421 | * caller might release the siglock and then the pending | |
422 | * stop signal it is about to process is no longer in the | |
423 | * pending bitmasks, but must still be cleared by a SIGCONT | |
424 | * (and overruled by a SIGKILL). So those cases clear this | |
425 | * shared flag after we've set it. Note that this flag may | |
426 | * remain set after the signal we return is ignored or | |
427 | * handled. That doesn't matter because its only purpose | |
428 | * is to alert stop-signal processing code when another | |
429 | * processor has come along and cleared the flag. | |
430 | */ | |
431 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) | |
432 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; | |
433 | } | |
c5363d03 | 434 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
435 | /* |
436 | * Release the siglock to ensure proper locking order | |
437 | * of timer locks outside of siglocks. Note, we leave | |
438 | * irqs disabled here, since the posix-timers code is | |
439 | * about to disable them again anyway. | |
440 | */ | |
441 | spin_unlock(&tsk->sighand->siglock); | |
442 | do_schedule_next_timer(info); | |
443 | spin_lock(&tsk->sighand->siglock); | |
444 | } | |
445 | return signr; | |
446 | } | |
447 | ||
448 | /* | |
449 | * Tell a process that it has a new active signal.. | |
450 | * | |
451 | * NOTE! we rely on the previous spin_lock to | |
452 | * lock interrupts for us! We can only be called with | |
453 | * "siglock" held, and the local interrupt must | |
454 | * have been disabled when that got acquired! | |
455 | * | |
456 | * No need to set need_resched since signal event passing | |
457 | * goes through ->blocked | |
458 | */ | |
459 | void signal_wake_up(struct task_struct *t, int resume) | |
460 | { | |
461 | unsigned int mask; | |
462 | ||
463 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
464 | ||
465 | /* | |
f021a3c2 MW |
466 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
467 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
468 | * executing another processor and just now entering stopped state. |
469 | * By using wake_up_state, we ensure the process will wake up and | |
470 | * handle its death signal. | |
471 | */ | |
472 | mask = TASK_INTERRUPTIBLE; | |
473 | if (resume) | |
f021a3c2 | 474 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
475 | if (!wake_up_state(t, mask)) |
476 | kick_process(t); | |
477 | } | |
478 | ||
71fabd5e GA |
479 | /* |
480 | * Remove signals in mask from the pending set and queue. | |
481 | * Returns 1 if any signals were found. | |
482 | * | |
483 | * All callers must be holding the siglock. | |
484 | * | |
485 | * This version takes a sigset mask and looks at all signals, | |
486 | * not just those in the first mask word. | |
487 | */ | |
488 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
489 | { | |
490 | struct sigqueue *q, *n; | |
491 | sigset_t m; | |
492 | ||
493 | sigandsets(&m, mask, &s->signal); | |
494 | if (sigisemptyset(&m)) | |
495 | return 0; | |
496 | ||
497 | signandsets(&s->signal, &s->signal, mask); | |
498 | list_for_each_entry_safe(q, n, &s->list, list) { | |
499 | if (sigismember(mask, q->info.si_signo)) { | |
500 | list_del_init(&q->list); | |
501 | __sigqueue_free(q); | |
502 | } | |
503 | } | |
504 | return 1; | |
505 | } | |
1da177e4 LT |
506 | /* |
507 | * Remove signals in mask from the pending set and queue. | |
508 | * Returns 1 if any signals were found. | |
509 | * | |
510 | * All callers must be holding the siglock. | |
511 | */ | |
512 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
513 | { | |
514 | struct sigqueue *q, *n; | |
515 | ||
516 | if (!sigtestsetmask(&s->signal, mask)) | |
517 | return 0; | |
518 | ||
519 | sigdelsetmask(&s->signal, mask); | |
520 | list_for_each_entry_safe(q, n, &s->list, list) { | |
521 | if (q->info.si_signo < SIGRTMIN && | |
522 | (mask & sigmask(q->info.si_signo))) { | |
523 | list_del_init(&q->list); | |
524 | __sigqueue_free(q); | |
525 | } | |
526 | } | |
527 | return 1; | |
528 | } | |
529 | ||
530 | /* | |
531 | * Bad permissions for sending the signal | |
532 | */ | |
533 | static int check_kill_permission(int sig, struct siginfo *info, | |
534 | struct task_struct *t) | |
535 | { | |
3b5e9e53 ON |
536 | int error; |
537 | ||
7ed20e1a | 538 | if (!valid_signal(sig)) |
3b5e9e53 ON |
539 | return -EINVAL; |
540 | ||
541 | if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info))) | |
542 | return 0; | |
e54dc243 | 543 | |
3b5e9e53 ON |
544 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
545 | if (error) | |
1da177e4 | 546 | return error; |
3b5e9e53 ON |
547 | |
548 | if (((sig != SIGCONT) || (task_session_nr(current) != task_session_nr(t))) | |
549 | && (current->euid ^ t->suid) && (current->euid ^ t->uid) | |
550 | && (current->uid ^ t->suid) && (current->uid ^ t->uid) | |
551 | && !capable(CAP_KILL)) | |
552 | return -EPERM; | |
c2f0c7c3 | 553 | |
e54dc243 | 554 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
555 | } |
556 | ||
557 | /* forward decl */ | |
a1d5e21e | 558 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why); |
1da177e4 LT |
559 | |
560 | /* | |
7e695a5e ON |
561 | * Handle magic process-wide effects of stop/continue signals. Unlike |
562 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
563 | * time regardless of blocking, ignoring, or handling. This does the |
564 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
565 | * signals. The process stop is done as a signal action for SIG_DFL. |
566 | * | |
567 | * Returns true if the signal should be actually delivered, otherwise | |
568 | * it should be dropped. | |
1da177e4 | 569 | */ |
7e695a5e | 570 | static int prepare_signal(int sig, struct task_struct *p) |
1da177e4 | 571 | { |
ad16a460 | 572 | struct signal_struct *signal = p->signal; |
1da177e4 LT |
573 | struct task_struct *t; |
574 | ||
7e695a5e | 575 | if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) { |
1da177e4 | 576 | /* |
7e695a5e | 577 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 578 | */ |
7e695a5e | 579 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
580 | /* |
581 | * This is a stop signal. Remove SIGCONT from all queues. | |
582 | */ | |
ad16a460 | 583 | rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); |
1da177e4 LT |
584 | t = p; |
585 | do { | |
586 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
ad16a460 | 587 | } while_each_thread(p, t); |
1da177e4 | 588 | } else if (sig == SIGCONT) { |
fc321d2e | 589 | unsigned int why; |
1da177e4 LT |
590 | /* |
591 | * Remove all stop signals from all queues, | |
592 | * and wake all threads. | |
593 | */ | |
ad16a460 | 594 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
595 | t = p; |
596 | do { | |
597 | unsigned int state; | |
598 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
1da177e4 LT |
599 | /* |
600 | * If there is a handler for SIGCONT, we must make | |
601 | * sure that no thread returns to user mode before | |
602 | * we post the signal, in case it was the only | |
603 | * thread eligible to run the signal handler--then | |
604 | * it must not do anything between resuming and | |
605 | * running the handler. With the TIF_SIGPENDING | |
606 | * flag set, the thread will pause and acquire the | |
607 | * siglock that we hold now and until we've queued | |
fc321d2e | 608 | * the pending signal. |
1da177e4 LT |
609 | * |
610 | * Wake up the stopped thread _after_ setting | |
611 | * TIF_SIGPENDING | |
612 | */ | |
f021a3c2 | 613 | state = __TASK_STOPPED; |
1da177e4 LT |
614 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { |
615 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
616 | state |= TASK_INTERRUPTIBLE; | |
617 | } | |
618 | wake_up_state(t, state); | |
ad16a460 | 619 | } while_each_thread(p, t); |
1da177e4 | 620 | |
fc321d2e ON |
621 | /* |
622 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
623 | * | |
624 | * If we were in the middle of a group stop, we pretend it | |
625 | * was already finished, and then continued. Since SIGCHLD | |
626 | * doesn't queue we report only CLD_STOPPED, as if the next | |
627 | * CLD_CONTINUED was dropped. | |
628 | */ | |
629 | why = 0; | |
ad16a460 | 630 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 631 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 632 | else if (signal->group_stop_count) |
fc321d2e ON |
633 | why |= SIGNAL_CLD_STOPPED; |
634 | ||
635 | if (why) { | |
021e1ae3 ON |
636 | /* |
637 | * The first thread which returns from finish_stop() | |
638 | * will take ->siglock, notice SIGNAL_CLD_MASK, and | |
639 | * notify its parent. See get_signal_to_deliver(). | |
640 | */ | |
ad16a460 ON |
641 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
642 | signal->group_stop_count = 0; | |
643 | signal->group_exit_code = 0; | |
1da177e4 LT |
644 | } else { |
645 | /* | |
646 | * We are not stopped, but there could be a stop | |
647 | * signal in the middle of being processed after | |
648 | * being removed from the queue. Clear that too. | |
649 | */ | |
ad16a460 | 650 | signal->flags &= ~SIGNAL_STOP_DEQUEUED; |
1da177e4 | 651 | } |
1da177e4 | 652 | } |
7e695a5e ON |
653 | |
654 | return !sig_ignored(p, sig); | |
1da177e4 LT |
655 | } |
656 | ||
71f11dc0 ON |
657 | /* |
658 | * Test if P wants to take SIG. After we've checked all threads with this, | |
659 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
660 | * blocking SIG were ruled out because they are not running and already | |
661 | * have pending signals. Such threads will dequeue from the shared queue | |
662 | * as soon as they're available, so putting the signal on the shared queue | |
663 | * will be equivalent to sending it to one such thread. | |
664 | */ | |
665 | static inline int wants_signal(int sig, struct task_struct *p) | |
666 | { | |
667 | if (sigismember(&p->blocked, sig)) | |
668 | return 0; | |
669 | if (p->flags & PF_EXITING) | |
670 | return 0; | |
671 | if (sig == SIGKILL) | |
672 | return 1; | |
673 | if (task_is_stopped_or_traced(p)) | |
674 | return 0; | |
675 | return task_curr(p) || !signal_pending(p); | |
676 | } | |
677 | ||
5fcd835b | 678 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
679 | { |
680 | struct signal_struct *signal = p->signal; | |
681 | struct task_struct *t; | |
682 | ||
683 | /* | |
684 | * Now find a thread we can wake up to take the signal off the queue. | |
685 | * | |
686 | * If the main thread wants the signal, it gets first crack. | |
687 | * Probably the least surprising to the average bear. | |
688 | */ | |
689 | if (wants_signal(sig, p)) | |
690 | t = p; | |
5fcd835b | 691 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
692 | /* |
693 | * There is just one thread and it does not need to be woken. | |
694 | * It will dequeue unblocked signals before it runs again. | |
695 | */ | |
696 | return; | |
697 | else { | |
698 | /* | |
699 | * Otherwise try to find a suitable thread. | |
700 | */ | |
701 | t = signal->curr_target; | |
702 | while (!wants_signal(sig, t)) { | |
703 | t = next_thread(t); | |
704 | if (t == signal->curr_target) | |
705 | /* | |
706 | * No thread needs to be woken. | |
707 | * Any eligible threads will see | |
708 | * the signal in the queue soon. | |
709 | */ | |
710 | return; | |
711 | } | |
712 | signal->curr_target = t; | |
713 | } | |
714 | ||
715 | /* | |
716 | * Found a killable thread. If the signal will be fatal, | |
717 | * then start taking the whole group down immediately. | |
718 | */ | |
719 | if (sig_fatal(p, sig) && !(signal->flags & SIGNAL_GROUP_EXIT) && | |
720 | !sigismember(&t->real_blocked, sig) && | |
721 | (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { | |
722 | /* | |
723 | * This signal will be fatal to the whole group. | |
724 | */ | |
725 | if (!sig_kernel_coredump(sig)) { | |
726 | /* | |
727 | * Start a group exit and wake everybody up. | |
728 | * This way we don't have other threads | |
729 | * running and doing things after a slower | |
730 | * thread has the fatal signal pending. | |
731 | */ | |
732 | signal->flags = SIGNAL_GROUP_EXIT; | |
733 | signal->group_exit_code = sig; | |
734 | signal->group_stop_count = 0; | |
735 | t = p; | |
736 | do { | |
737 | sigaddset(&t->pending.signal, SIGKILL); | |
738 | signal_wake_up(t, 1); | |
739 | } while_each_thread(p, t); | |
740 | return; | |
741 | } | |
742 | } | |
743 | ||
744 | /* | |
745 | * The signal is already in the shared-pending queue. | |
746 | * Tell the chosen thread to wake up and dequeue it. | |
747 | */ | |
748 | signal_wake_up(t, sig == SIGKILL); | |
749 | return; | |
750 | } | |
751 | ||
af7fff9c PE |
752 | static inline int legacy_queue(struct sigpending *signals, int sig) |
753 | { | |
754 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
755 | } | |
756 | ||
1da177e4 | 757 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
2ca3515a | 758 | int group) |
1da177e4 | 759 | { |
2ca3515a | 760 | struct sigpending *pending; |
6e65acba | 761 | struct sigqueue *q; |
1da177e4 | 762 | |
6e65acba | 763 | assert_spin_locked(&t->sighand->siglock); |
7e695a5e ON |
764 | if (!prepare_signal(sig, t)) |
765 | return 0; | |
2ca3515a ON |
766 | |
767 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
768 | /* |
769 | * Short-circuit ignored signals and support queuing | |
770 | * exactly one non-rt signal, so that we can get more | |
771 | * detailed information about the cause of the signal. | |
772 | */ | |
7e695a5e | 773 | if (legacy_queue(pending, sig)) |
2acb024d | 774 | return 0; |
1da177e4 LT |
775 | /* |
776 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
777 | * or SIGKILL. | |
778 | */ | |
b67a1b9e | 779 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
780 | goto out_set; |
781 | ||
782 | /* Real-time signals must be queued if sent by sigqueue, or | |
783 | some other real-time mechanism. It is implementation | |
784 | defined whether kill() does so. We attempt to do so, on | |
785 | the principle of least surprise, but since kill is not | |
786 | allowed to fail with EAGAIN when low on memory we just | |
787 | make sure at least one signal gets delivered and don't | |
788 | pass on the info struct. */ | |
789 | ||
790 | q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN && | |
621d3121 | 791 | (is_si_special(info) || |
1da177e4 LT |
792 | info->si_code >= 0))); |
793 | if (q) { | |
2ca3515a | 794 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 795 | switch ((unsigned long) info) { |
b67a1b9e | 796 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
797 | q->info.si_signo = sig; |
798 | q->info.si_errno = 0; | |
799 | q->info.si_code = SI_USER; | |
b488893a | 800 | q->info.si_pid = task_pid_vnr(current); |
1da177e4 LT |
801 | q->info.si_uid = current->uid; |
802 | break; | |
b67a1b9e | 803 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
804 | q->info.si_signo = sig; |
805 | q->info.si_errno = 0; | |
806 | q->info.si_code = SI_KERNEL; | |
807 | q->info.si_pid = 0; | |
808 | q->info.si_uid = 0; | |
809 | break; | |
810 | default: | |
811 | copy_siginfo(&q->info, info); | |
812 | break; | |
813 | } | |
621d3121 ON |
814 | } else if (!is_si_special(info)) { |
815 | if (sig >= SIGRTMIN && info->si_code != SI_USER) | |
1da177e4 LT |
816 | /* |
817 | * Queue overflow, abort. We may abort if the signal was rt | |
818 | * and sent by user using something other than kill(). | |
819 | */ | |
820 | return -EAGAIN; | |
1da177e4 LT |
821 | } |
822 | ||
823 | out_set: | |
53c30337 | 824 | signalfd_notify(t, sig); |
2ca3515a | 825 | sigaddset(&pending->signal, sig); |
4cd4b6d4 PE |
826 | complete_signal(sig, t, group); |
827 | return 0; | |
1da177e4 LT |
828 | } |
829 | ||
45807a1d IM |
830 | int print_fatal_signals; |
831 | ||
832 | static void print_fatal_signal(struct pt_regs *regs, int signr) | |
833 | { | |
834 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 835 | current->comm, task_pid_nr(current), signr); |
45807a1d | 836 | |
ca5cd877 | 837 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 838 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
839 | { |
840 | int i; | |
841 | for (i = 0; i < 16; i++) { | |
842 | unsigned char insn; | |
843 | ||
65ea5b03 | 844 | __get_user(insn, (unsigned char *)(regs->ip + i)); |
45807a1d IM |
845 | printk("%02x ", insn); |
846 | } | |
847 | } | |
848 | #endif | |
849 | printk("\n"); | |
850 | show_regs(regs); | |
851 | } | |
852 | ||
853 | static int __init setup_print_fatal_signals(char *str) | |
854 | { | |
855 | get_option (&str, &print_fatal_signals); | |
856 | ||
857 | return 1; | |
858 | } | |
859 | ||
860 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 861 | |
4cd4b6d4 PE |
862 | int |
863 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
864 | { | |
865 | return send_signal(sig, info, p, 1); | |
866 | } | |
867 | ||
1da177e4 LT |
868 | static int |
869 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
870 | { | |
4cd4b6d4 | 871 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
872 | } |
873 | ||
874 | /* | |
875 | * Force a signal that the process can't ignore: if necessary | |
876 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
877 | * |
878 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
879 | * since we do not want to have a signal handler that was blocked | |
880 | * be invoked when user space had explicitly blocked it. | |
881 | * | |
882 | * We don't want to have recursive SIGSEGV's etc, for example. | |
1da177e4 | 883 | */ |
1da177e4 LT |
884 | int |
885 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
886 | { | |
887 | unsigned long int flags; | |
ae74c3b6 LT |
888 | int ret, blocked, ignored; |
889 | struct k_sigaction *action; | |
1da177e4 LT |
890 | |
891 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
892 | action = &t->sighand->action[sig-1]; |
893 | ignored = action->sa.sa_handler == SIG_IGN; | |
894 | blocked = sigismember(&t->blocked, sig); | |
895 | if (blocked || ignored) { | |
896 | action->sa.sa_handler = SIG_DFL; | |
897 | if (blocked) { | |
898 | sigdelset(&t->blocked, sig); | |
7bb44ade | 899 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 900 | } |
1da177e4 LT |
901 | } |
902 | ret = specific_send_sig_info(sig, info, t); | |
903 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
904 | ||
905 | return ret; | |
906 | } | |
907 | ||
908 | void | |
909 | force_sig_specific(int sig, struct task_struct *t) | |
910 | { | |
b0423a0d | 911 | force_sig_info(sig, SEND_SIG_FORCED, t); |
1da177e4 LT |
912 | } |
913 | ||
1da177e4 LT |
914 | /* |
915 | * Nuke all other threads in the group. | |
916 | */ | |
917 | void zap_other_threads(struct task_struct *p) | |
918 | { | |
919 | struct task_struct *t; | |
920 | ||
1da177e4 LT |
921 | p->signal->group_stop_count = 0; |
922 | ||
1da177e4 LT |
923 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
924 | /* | |
925 | * Don't bother with already dead threads | |
926 | */ | |
927 | if (t->exit_state) | |
928 | continue; | |
929 | ||
30e0fca6 | 930 | /* SIGKILL will be handled before any pending SIGSTOP */ |
1da177e4 | 931 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
932 | signal_wake_up(t, 1); |
933 | } | |
934 | } | |
935 | ||
b5606c2d | 936 | int __fatal_signal_pending(struct task_struct *tsk) |
f776d12d MW |
937 | { |
938 | return sigismember(&tsk->pending.signal, SIGKILL); | |
939 | } | |
13f09b95 | 940 | EXPORT_SYMBOL(__fatal_signal_pending); |
f776d12d | 941 | |
f63ee72e ON |
942 | struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) |
943 | { | |
944 | struct sighand_struct *sighand; | |
945 | ||
1406f2d3 | 946 | rcu_read_lock(); |
f63ee72e ON |
947 | for (;;) { |
948 | sighand = rcu_dereference(tsk->sighand); | |
949 | if (unlikely(sighand == NULL)) | |
950 | break; | |
951 | ||
952 | spin_lock_irqsave(&sighand->siglock, *flags); | |
953 | if (likely(sighand == tsk->sighand)) | |
954 | break; | |
955 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
956 | } | |
1406f2d3 | 957 | rcu_read_unlock(); |
f63ee72e ON |
958 | |
959 | return sighand; | |
960 | } | |
961 | ||
1da177e4 LT |
962 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
963 | { | |
964 | unsigned long flags; | |
965 | int ret; | |
966 | ||
967 | ret = check_kill_permission(sig, info, p); | |
f63ee72e ON |
968 | |
969 | if (!ret && sig) { | |
970 | ret = -ESRCH; | |
971 | if (lock_task_sighand(p, &flags)) { | |
972 | ret = __group_send_sig_info(sig, info, p); | |
973 | unlock_task_sighand(p, &flags); | |
2d89c929 | 974 | } |
1da177e4 LT |
975 | } |
976 | ||
977 | return ret; | |
978 | } | |
979 | ||
980 | /* | |
146a505d | 981 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 LT |
982 | * control characters do (^C, ^Z etc) |
983 | */ | |
984 | ||
c4b92fc1 | 985 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
986 | { |
987 | struct task_struct *p = NULL; | |
988 | int retval, success; | |
989 | ||
1da177e4 LT |
990 | success = 0; |
991 | retval = -ESRCH; | |
c4b92fc1 | 992 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
993 | int err = group_send_sig_info(sig, info, p); |
994 | success |= !err; | |
995 | retval = err; | |
c4b92fc1 | 996 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
997 | return success ? 0 : retval; |
998 | } | |
999 | ||
c4b92fc1 | 1000 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1001 | { |
d36174bc | 1002 | int error = -ESRCH; |
1da177e4 LT |
1003 | struct task_struct *p; |
1004 | ||
e56d0903 | 1005 | rcu_read_lock(); |
d36174bc | 1006 | retry: |
c4b92fc1 | 1007 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1008 | if (p) { |
1da177e4 | 1009 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1010 | if (unlikely(error == -ESRCH)) |
1011 | /* | |
1012 | * The task was unhashed in between, try again. | |
1013 | * If it is dead, pid_task() will return NULL, | |
1014 | * if we race with de_thread() it will find the | |
1015 | * new leader. | |
1016 | */ | |
1017 | goto retry; | |
1018 | } | |
e56d0903 | 1019 | rcu_read_unlock(); |
6ca25b55 | 1020 | |
1da177e4 LT |
1021 | return error; |
1022 | } | |
1023 | ||
c3de4b38 MW |
1024 | int |
1025 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
c4b92fc1 EB |
1026 | { |
1027 | int error; | |
1028 | rcu_read_lock(); | |
b488893a | 1029 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1030 | rcu_read_unlock(); |
1031 | return error; | |
1032 | } | |
1033 | ||
2425c08b EB |
1034 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1035 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1036 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1037 | { |
1038 | int ret = -EINVAL; | |
1039 | struct task_struct *p; | |
1040 | ||
1041 | if (!valid_signal(sig)) | |
1042 | return ret; | |
1043 | ||
1044 | read_lock(&tasklist_lock); | |
2425c08b | 1045 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1046 | if (!p) { |
1047 | ret = -ESRCH; | |
1048 | goto out_unlock; | |
1049 | } | |
0811af28 | 1050 | if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) |
46113830 HW |
1051 | && (euid != p->suid) && (euid != p->uid) |
1052 | && (uid != p->suid) && (uid != p->uid)) { | |
1053 | ret = -EPERM; | |
1054 | goto out_unlock; | |
1055 | } | |
8f95dc58 DQ |
1056 | ret = security_task_kill(p, info, sig, secid); |
1057 | if (ret) | |
1058 | goto out_unlock; | |
46113830 HW |
1059 | if (sig && p->sighand) { |
1060 | unsigned long flags; | |
1061 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1062 | ret = __group_send_sig_info(sig, info, p); | |
1063 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1064 | } | |
1065 | out_unlock: | |
1066 | read_unlock(&tasklist_lock); | |
1067 | return ret; | |
1068 | } | |
2425c08b | 1069 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1070 | |
1071 | /* | |
1072 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1073 | * | |
1074 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1075 | * is probably wrong. Should make it like BSD or SYSV. | |
1076 | */ | |
1077 | ||
1078 | static int kill_something_info(int sig, struct siginfo *info, int pid) | |
1079 | { | |
8d42db18 | 1080 | int ret; |
d5df763b PE |
1081 | |
1082 | if (pid > 0) { | |
1083 | rcu_read_lock(); | |
1084 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1085 | rcu_read_unlock(); | |
1086 | return ret; | |
1087 | } | |
1088 | ||
1089 | read_lock(&tasklist_lock); | |
1090 | if (pid != -1) { | |
1091 | ret = __kill_pgrp_info(sig, info, | |
1092 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1093 | } else { | |
1da177e4 LT |
1094 | int retval = 0, count = 0; |
1095 | struct task_struct * p; | |
1096 | ||
1da177e4 | 1097 | for_each_process(p) { |
bac0abd6 | 1098 | if (p->pid > 1 && !same_thread_group(p, current)) { |
1da177e4 LT |
1099 | int err = group_send_sig_info(sig, info, p); |
1100 | ++count; | |
1101 | if (err != -EPERM) | |
1102 | retval = err; | |
1103 | } | |
1104 | } | |
8d42db18 | 1105 | ret = count ? retval : -ESRCH; |
1da177e4 | 1106 | } |
d5df763b PE |
1107 | read_unlock(&tasklist_lock); |
1108 | ||
8d42db18 | 1109 | return ret; |
1da177e4 LT |
1110 | } |
1111 | ||
1112 | /* | |
1113 | * These are for backward compatibility with the rest of the kernel source. | |
1114 | */ | |
1115 | ||
1116 | /* | |
08d2c30c | 1117 | * The caller must ensure the task can't exit. |
1da177e4 LT |
1118 | */ |
1119 | int | |
1120 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1121 | { | |
1122 | int ret; | |
1123 | unsigned long flags; | |
1124 | ||
1125 | /* | |
1126 | * Make sure legacy kernel users don't send in bad values | |
1127 | * (normal paths check this in check_kill_permission). | |
1128 | */ | |
7ed20e1a | 1129 | if (!valid_signal(sig)) |
1da177e4 LT |
1130 | return -EINVAL; |
1131 | ||
1da177e4 LT |
1132 | spin_lock_irqsave(&p->sighand->siglock, flags); |
1133 | ret = specific_send_sig_info(sig, info, p); | |
1134 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1da177e4 LT |
1135 | return ret; |
1136 | } | |
1137 | ||
b67a1b9e ON |
1138 | #define __si_special(priv) \ |
1139 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1140 | ||
1da177e4 LT |
1141 | int |
1142 | send_sig(int sig, struct task_struct *p, int priv) | |
1143 | { | |
b67a1b9e | 1144 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1145 | } |
1146 | ||
1da177e4 LT |
1147 | void |
1148 | force_sig(int sig, struct task_struct *p) | |
1149 | { | |
b67a1b9e | 1150 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1151 | } |
1152 | ||
1153 | /* | |
1154 | * When things go south during signal handling, we | |
1155 | * will force a SIGSEGV. And if the signal that caused | |
1156 | * the problem was already a SIGSEGV, we'll want to | |
1157 | * make sure we don't even try to deliver the signal.. | |
1158 | */ | |
1159 | int | |
1160 | force_sigsegv(int sig, struct task_struct *p) | |
1161 | { | |
1162 | if (sig == SIGSEGV) { | |
1163 | unsigned long flags; | |
1164 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1165 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1166 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1167 | } | |
1168 | force_sig(SIGSEGV, p); | |
1169 | return 0; | |
1170 | } | |
1171 | ||
c4b92fc1 EB |
1172 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1173 | { | |
146a505d PE |
1174 | int ret; |
1175 | ||
1176 | read_lock(&tasklist_lock); | |
1177 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1178 | read_unlock(&tasklist_lock); | |
1179 | ||
1180 | return ret; | |
c4b92fc1 EB |
1181 | } |
1182 | EXPORT_SYMBOL(kill_pgrp); | |
1183 | ||
1184 | int kill_pid(struct pid *pid, int sig, int priv) | |
1185 | { | |
1186 | return kill_pid_info(sig, __si_special(priv), pid); | |
1187 | } | |
1188 | EXPORT_SYMBOL(kill_pid); | |
1189 | ||
1da177e4 LT |
1190 | int |
1191 | kill_proc(pid_t pid, int sig, int priv) | |
1192 | { | |
b488893a PE |
1193 | int ret; |
1194 | ||
1195 | rcu_read_lock(); | |
1196 | ret = kill_pid_info(sig, __si_special(priv), find_pid(pid)); | |
1197 | rcu_read_unlock(); | |
1198 | return ret; | |
1da177e4 LT |
1199 | } |
1200 | ||
1201 | /* | |
1202 | * These functions support sending signals using preallocated sigqueue | |
1203 | * structures. This is needed "because realtime applications cannot | |
1204 | * afford to lose notifications of asynchronous events, like timer | |
1205 | * expirations or I/O completions". In the case of Posix Timers | |
1206 | * we allocate the sigqueue structure from the timer_create. If this | |
1207 | * allocation fails we are able to report the failure to the application | |
1208 | * with an EAGAIN error. | |
1209 | */ | |
1210 | ||
1211 | struct sigqueue *sigqueue_alloc(void) | |
1212 | { | |
1213 | struct sigqueue *q; | |
1214 | ||
1215 | if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) | |
1216 | q->flags |= SIGQUEUE_PREALLOC; | |
1217 | return(q); | |
1218 | } | |
1219 | ||
1220 | void sigqueue_free(struct sigqueue *q) | |
1221 | { | |
1222 | unsigned long flags; | |
60187d27 ON |
1223 | spinlock_t *lock = ¤t->sighand->siglock; |
1224 | ||
1da177e4 LT |
1225 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1226 | /* | |
1227 | * If the signal is still pending remove it from the | |
60187d27 ON |
1228 | * pending queue. We must hold ->siglock while testing |
1229 | * q->list to serialize with collect_signal(). | |
1da177e4 | 1230 | */ |
60187d27 ON |
1231 | spin_lock_irqsave(lock, flags); |
1232 | if (!list_empty(&q->list)) | |
1233 | list_del_init(&q->list); | |
1234 | spin_unlock_irqrestore(lock, flags); | |
1235 | ||
1da177e4 LT |
1236 | q->flags &= ~SIGQUEUE_PREALLOC; |
1237 | __sigqueue_free(q); | |
1238 | } | |
1239 | ||
ac5c2153 | 1240 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1241 | { |
e62e6650 | 1242 | int sig = q->info.si_signo; |
2ca3515a | 1243 | struct sigpending *pending; |
e62e6650 ON |
1244 | unsigned long flags; |
1245 | int ret; | |
2ca3515a | 1246 | |
4cd4b6d4 | 1247 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1248 | |
1249 | ret = -1; | |
1250 | if (!likely(lock_task_sighand(t, &flags))) | |
1251 | goto ret; | |
1252 | ||
7e695a5e ON |
1253 | ret = 1; /* the signal is ignored */ |
1254 | if (!prepare_signal(sig, t)) | |
e62e6650 ON |
1255 | goto out; |
1256 | ||
1257 | ret = 0; | |
9e3bd6c3 PE |
1258 | if (unlikely(!list_empty(&q->list))) { |
1259 | /* | |
1260 | * If an SI_TIMER entry is already queue just increment | |
1261 | * the overrun count. | |
1262 | */ | |
9e3bd6c3 PE |
1263 | BUG_ON(q->info.si_code != SI_TIMER); |
1264 | q->info.si_overrun++; | |
e62e6650 | 1265 | goto out; |
9e3bd6c3 PE |
1266 | } |
1267 | ||
9e3bd6c3 | 1268 | signalfd_notify(t, sig); |
2ca3515a | 1269 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1270 | list_add_tail(&q->list, &pending->list); |
1271 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1272 | complete_signal(sig, t, group); |
e62e6650 ON |
1273 | out: |
1274 | unlock_task_sighand(t, &flags); | |
1275 | ret: | |
1276 | return ret; | |
9e3bd6c3 PE |
1277 | } |
1278 | ||
1da177e4 LT |
1279 | /* |
1280 | * Wake up any threads in the parent blocked in wait* syscalls. | |
1281 | */ | |
1282 | static inline void __wake_up_parent(struct task_struct *p, | |
1283 | struct task_struct *parent) | |
1284 | { | |
1285 | wake_up_interruptible_sync(&parent->signal->wait_chldexit); | |
1286 | } | |
1287 | ||
1288 | /* | |
1289 | * Let a parent know about the death of a child. | |
1290 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
1291 | */ | |
1292 | ||
1293 | void do_notify_parent(struct task_struct *tsk, int sig) | |
1294 | { | |
1295 | struct siginfo info; | |
1296 | unsigned long flags; | |
1297 | struct sighand_struct *psig; | |
1298 | ||
1299 | BUG_ON(sig == -1); | |
1300 | ||
1301 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1302 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 LT |
1303 | |
1304 | BUG_ON(!tsk->ptrace && | |
1305 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); | |
1306 | ||
1307 | info.si_signo = sig; | |
1308 | info.si_errno = 0; | |
b488893a PE |
1309 | /* |
1310 | * we are under tasklist_lock here so our parent is tied to | |
1311 | * us and cannot exit and release its namespace. | |
1312 | * | |
1313 | * the only it can is to switch its nsproxy with sys_unshare, | |
1314 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1315 | * see relevant namespace | |
1316 | * | |
1317 | * write_lock() currently calls preempt_disable() which is the | |
1318 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1319 | * correct to rely on this | |
1320 | */ | |
1321 | rcu_read_lock(); | |
1322 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
1323 | rcu_read_unlock(); | |
1324 | ||
1da177e4 LT |
1325 | info.si_uid = tsk->uid; |
1326 | ||
1327 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1328 | info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime, | |
1329 | tsk->signal->utime)); | |
1330 | info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime, | |
1331 | tsk->signal->stime)); | |
1332 | ||
1333 | info.si_status = tsk->exit_code & 0x7f; | |
1334 | if (tsk->exit_code & 0x80) | |
1335 | info.si_code = CLD_DUMPED; | |
1336 | else if (tsk->exit_code & 0x7f) | |
1337 | info.si_code = CLD_KILLED; | |
1338 | else { | |
1339 | info.si_code = CLD_EXITED; | |
1340 | info.si_status = tsk->exit_code >> 8; | |
1341 | } | |
1342 | ||
1343 | psig = tsk->parent->sighand; | |
1344 | spin_lock_irqsave(&psig->siglock, flags); | |
7ed0175a | 1345 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1346 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1347 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1348 | /* | |
1349 | * We are exiting and our parent doesn't care. POSIX.1 | |
1350 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1351 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1352 | * automatically and not left for our parent's wait4 call. | |
1353 | * Rather than having the parent do it as a magic kind of | |
1354 | * signal handler, we just set this to tell do_exit that we | |
1355 | * can be cleaned up without becoming a zombie. Note that | |
1356 | * we still call __wake_up_parent in this case, because a | |
1357 | * blocked sys_wait4 might now return -ECHILD. | |
1358 | * | |
1359 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1360 | * is implementation-defined: we do (if you don't want | |
1361 | * it, just use SIG_IGN instead). | |
1362 | */ | |
1363 | tsk->exit_signal = -1; | |
1364 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) | |
1365 | sig = 0; | |
1366 | } | |
7ed20e1a | 1367 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1368 | __group_send_sig_info(sig, &info, tsk->parent); |
1369 | __wake_up_parent(tsk, tsk->parent); | |
1370 | spin_unlock_irqrestore(&psig->siglock, flags); | |
1371 | } | |
1372 | ||
a1d5e21e | 1373 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why) |
1da177e4 LT |
1374 | { |
1375 | struct siginfo info; | |
1376 | unsigned long flags; | |
bc505a47 | 1377 | struct task_struct *parent; |
1da177e4 LT |
1378 | struct sighand_struct *sighand; |
1379 | ||
a1d5e21e | 1380 | if (tsk->ptrace & PT_PTRACED) |
bc505a47 ON |
1381 | parent = tsk->parent; |
1382 | else { | |
1383 | tsk = tsk->group_leader; | |
1384 | parent = tsk->real_parent; | |
1385 | } | |
1386 | ||
1da177e4 LT |
1387 | info.si_signo = SIGCHLD; |
1388 | info.si_errno = 0; | |
b488893a PE |
1389 | /* |
1390 | * see comment in do_notify_parent() abot the following 3 lines | |
1391 | */ | |
1392 | rcu_read_lock(); | |
1393 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
1394 | rcu_read_unlock(); | |
1395 | ||
1da177e4 LT |
1396 | info.si_uid = tsk->uid; |
1397 | ||
1398 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1399 | info.si_utime = cputime_to_jiffies(tsk->utime); | |
1400 | info.si_stime = cputime_to_jiffies(tsk->stime); | |
1401 | ||
1402 | info.si_code = why; | |
1403 | switch (why) { | |
1404 | case CLD_CONTINUED: | |
1405 | info.si_status = SIGCONT; | |
1406 | break; | |
1407 | case CLD_STOPPED: | |
1408 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1409 | break; | |
1410 | case CLD_TRAPPED: | |
1411 | info.si_status = tsk->exit_code & 0x7f; | |
1412 | break; | |
1413 | default: | |
1414 | BUG(); | |
1415 | } | |
1416 | ||
1417 | sighand = parent->sighand; | |
1418 | spin_lock_irqsave(&sighand->siglock, flags); | |
1419 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1420 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1421 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1422 | /* | |
1423 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1424 | */ | |
1425 | __wake_up_parent(tsk, parent); | |
1426 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1427 | } | |
1428 | ||
d5f70c00 ON |
1429 | static inline int may_ptrace_stop(void) |
1430 | { | |
1431 | if (!likely(current->ptrace & PT_PTRACED)) | |
1432 | return 0; | |
d5f70c00 ON |
1433 | /* |
1434 | * Are we in the middle of do_coredump? | |
1435 | * If so and our tracer is also part of the coredump stopping | |
1436 | * is a deadlock situation, and pointless because our tracer | |
1437 | * is dead so don't allow us to stop. | |
1438 | * If SIGKILL was already sent before the caller unlocked | |
1439 | * ->siglock we must see ->core_waiters != 0. Otherwise it | |
1440 | * is safe to enter schedule(). | |
1441 | */ | |
1442 | if (unlikely(current->mm->core_waiters) && | |
1443 | unlikely(current->mm == current->parent->mm)) | |
1444 | return 0; | |
1445 | ||
1446 | return 1; | |
1447 | } | |
1448 | ||
1a669c2f RM |
1449 | /* |
1450 | * Return nonzero if there is a SIGKILL that should be waking us up. | |
1451 | * Called with the siglock held. | |
1452 | */ | |
1453 | static int sigkill_pending(struct task_struct *tsk) | |
1454 | { | |
1455 | return ((sigismember(&tsk->pending.signal, SIGKILL) || | |
1456 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) && | |
1457 | !unlikely(sigismember(&tsk->blocked, SIGKILL))); | |
1458 | } | |
1459 | ||
1da177e4 LT |
1460 | /* |
1461 | * This must be called with current->sighand->siglock held. | |
1462 | * | |
1463 | * This should be the path for all ptrace stops. | |
1464 | * We always set current->last_siginfo while stopped here. | |
1465 | * That makes it a way to test a stopped process for | |
1466 | * being ptrace-stopped vs being job-control-stopped. | |
1467 | * | |
20686a30 ON |
1468 | * If we actually decide not to stop at all because the tracer |
1469 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1470 | */ |
20686a30 | 1471 | static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) |
1da177e4 | 1472 | { |
1a669c2f RM |
1473 | int killed = 0; |
1474 | ||
1475 | if (arch_ptrace_stop_needed(exit_code, info)) { | |
1476 | /* | |
1477 | * The arch code has something special to do before a | |
1478 | * ptrace stop. This is allowed to block, e.g. for faults | |
1479 | * on user stack pages. We can't keep the siglock while | |
1480 | * calling arch_ptrace_stop, so we must release it now. | |
1481 | * To preserve proper semantics, we must do this before | |
1482 | * any signal bookkeeping like checking group_stop_count. | |
1483 | * Meanwhile, a SIGKILL could come in before we retake the | |
1484 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1485 | * So after regaining the lock, we must check for SIGKILL. | |
1486 | */ | |
1487 | spin_unlock_irq(¤t->sighand->siglock); | |
1488 | arch_ptrace_stop(exit_code, info); | |
1489 | spin_lock_irq(¤t->sighand->siglock); | |
1490 | killed = sigkill_pending(current); | |
1491 | } | |
1492 | ||
1da177e4 LT |
1493 | /* |
1494 | * If there is a group stop in progress, | |
1495 | * we must participate in the bookkeeping. | |
1496 | */ | |
1497 | if (current->signal->group_stop_count > 0) | |
1498 | --current->signal->group_stop_count; | |
1499 | ||
1500 | current->last_siginfo = info; | |
1501 | current->exit_code = exit_code; | |
1502 | ||
1503 | /* Let the debugger run. */ | |
d9ae90ac | 1504 | __set_current_state(TASK_TRACED); |
1da177e4 LT |
1505 | spin_unlock_irq(¤t->sighand->siglock); |
1506 | read_lock(&tasklist_lock); | |
1a669c2f | 1507 | if (!unlikely(killed) && may_ptrace_stop()) { |
a1d5e21e | 1508 | do_notify_parent_cldstop(current, CLD_TRAPPED); |
1da177e4 LT |
1509 | read_unlock(&tasklist_lock); |
1510 | schedule(); | |
1511 | } else { | |
1512 | /* | |
1513 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1514 | * Don't drop the lock yet, another tracer may come. |
1da177e4 | 1515 | */ |
6405f7f4 | 1516 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1517 | if (clear_code) |
1518 | current->exit_code = 0; | |
6405f7f4 | 1519 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1520 | } |
1521 | ||
13b1c3d4 RM |
1522 | /* |
1523 | * While in TASK_TRACED, we were considered "frozen enough". | |
1524 | * Now that we woke up, it's crucial if we're supposed to be | |
1525 | * frozen that we freeze now before running anything substantial. | |
1526 | */ | |
1527 | try_to_freeze(); | |
1528 | ||
1da177e4 LT |
1529 | /* |
1530 | * We are back. Now reacquire the siglock before touching | |
1531 | * last_siginfo, so that we are sure to have synchronized with | |
1532 | * any signal-sending on another CPU that wants to examine it. | |
1533 | */ | |
1534 | spin_lock_irq(¤t->sighand->siglock); | |
1535 | current->last_siginfo = NULL; | |
1536 | ||
1537 | /* | |
1538 | * Queued signals ignored us while we were stopped for tracing. | |
1539 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1540 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1541 | */ |
b74d0deb | 1542 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1543 | } |
1544 | ||
1545 | void ptrace_notify(int exit_code) | |
1546 | { | |
1547 | siginfo_t info; | |
1548 | ||
1549 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1550 | ||
1551 | memset(&info, 0, sizeof info); | |
1552 | info.si_signo = SIGTRAP; | |
1553 | info.si_code = exit_code; | |
b488893a | 1554 | info.si_pid = task_pid_vnr(current); |
1da177e4 LT |
1555 | info.si_uid = current->uid; |
1556 | ||
1557 | /* Let the debugger run. */ | |
1558 | spin_lock_irq(¤t->sighand->siglock); | |
20686a30 | 1559 | ptrace_stop(exit_code, 1, &info); |
1da177e4 LT |
1560 | spin_unlock_irq(¤t->sighand->siglock); |
1561 | } | |
1562 | ||
1da177e4 LT |
1563 | static void |
1564 | finish_stop(int stop_count) | |
1565 | { | |
1566 | /* | |
1567 | * If there are no other threads in the group, or if there is | |
1568 | * a group stop in progress and we are the last to stop, | |
1569 | * report to the parent. When ptraced, every thread reports itself. | |
1570 | */ | |
a1d5e21e ON |
1571 | if (stop_count == 0 || (current->ptrace & PT_PTRACED)) { |
1572 | read_lock(&tasklist_lock); | |
1573 | do_notify_parent_cldstop(current, CLD_STOPPED); | |
1574 | read_unlock(&tasklist_lock); | |
1575 | } | |
bc505a47 | 1576 | |
3df494a3 RW |
1577 | do { |
1578 | schedule(); | |
1579 | } while (try_to_freeze()); | |
1da177e4 LT |
1580 | /* |
1581 | * Now we don't run again until continued. | |
1582 | */ | |
1583 | current->exit_code = 0; | |
1584 | } | |
1585 | ||
1586 | /* | |
1587 | * This performs the stopping for SIGSTOP and other stop signals. | |
1588 | * We have to stop all threads in the thread group. | |
1589 | * Returns nonzero if we've actually stopped and released the siglock. | |
1590 | * Returns zero if we didn't stop and still hold the siglock. | |
1591 | */ | |
a122b341 | 1592 | static int do_signal_stop(int signr) |
1da177e4 LT |
1593 | { |
1594 | struct signal_struct *sig = current->signal; | |
dac27f4a | 1595 | int stop_count; |
1da177e4 | 1596 | |
1da177e4 LT |
1597 | if (sig->group_stop_count > 0) { |
1598 | /* | |
1599 | * There is a group stop in progress. We don't need to | |
1600 | * start another one. | |
1601 | */ | |
1da177e4 | 1602 | stop_count = --sig->group_stop_count; |
dac27f4a | 1603 | } else { |
f558b7e4 ON |
1604 | struct task_struct *t; |
1605 | ||
ed5d2cac | 1606 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) || |
573cf9ad | 1607 | unlikely(signal_group_exit(sig))) |
f558b7e4 | 1608 | return 0; |
1da177e4 LT |
1609 | /* |
1610 | * There is no group stop already in progress. | |
a122b341 | 1611 | * We must initiate one now. |
1da177e4 | 1612 | */ |
a122b341 | 1613 | sig->group_exit_code = signr; |
1da177e4 | 1614 | |
a122b341 ON |
1615 | stop_count = 0; |
1616 | for (t = next_thread(current); t != current; t = next_thread(t)) | |
1da177e4 | 1617 | /* |
a122b341 ON |
1618 | * Setting state to TASK_STOPPED for a group |
1619 | * stop is always done with the siglock held, | |
1620 | * so this check has no races. | |
1da177e4 | 1621 | */ |
d12619b5 | 1622 | if (!(t->flags & PF_EXITING) && |
e1abb39c | 1623 | !task_is_stopped_or_traced(t)) { |
a122b341 ON |
1624 | stop_count++; |
1625 | signal_wake_up(t, 0); | |
1626 | } | |
1627 | sig->group_stop_count = stop_count; | |
1da177e4 LT |
1628 | } |
1629 | ||
dac27f4a ON |
1630 | if (stop_count == 0) |
1631 | sig->flags = SIGNAL_STOP_STOPPED; | |
1632 | current->exit_code = sig->group_exit_code; | |
1633 | __set_current_state(TASK_STOPPED); | |
1634 | ||
1635 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
1636 | finish_stop(stop_count); |
1637 | return 1; | |
1638 | } | |
1639 | ||
18c98b65 RM |
1640 | static int ptrace_signal(int signr, siginfo_t *info, |
1641 | struct pt_regs *regs, void *cookie) | |
1642 | { | |
1643 | if (!(current->ptrace & PT_PTRACED)) | |
1644 | return signr; | |
1645 | ||
1646 | ptrace_signal_deliver(regs, cookie); | |
1647 | ||
1648 | /* Let the debugger run. */ | |
1649 | ptrace_stop(signr, 0, info); | |
1650 | ||
1651 | /* We're back. Did the debugger cancel the sig? */ | |
1652 | signr = current->exit_code; | |
1653 | if (signr == 0) | |
1654 | return signr; | |
1655 | ||
1656 | current->exit_code = 0; | |
1657 | ||
1658 | /* Update the siginfo structure if the signal has | |
1659 | changed. If the debugger wanted something | |
1660 | specific in the siginfo structure then it should | |
1661 | have updated *info via PTRACE_SETSIGINFO. */ | |
1662 | if (signr != info->si_signo) { | |
1663 | info->si_signo = signr; | |
1664 | info->si_errno = 0; | |
1665 | info->si_code = SI_USER; | |
1666 | info->si_pid = task_pid_vnr(current->parent); | |
1667 | info->si_uid = current->parent->uid; | |
1668 | } | |
1669 | ||
1670 | /* If the (new) signal is now blocked, requeue it. */ | |
1671 | if (sigismember(¤t->blocked, signr)) { | |
1672 | specific_send_sig_info(signr, info, current); | |
1673 | signr = 0; | |
1674 | } | |
1675 | ||
1676 | return signr; | |
1677 | } | |
1678 | ||
1da177e4 LT |
1679 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
1680 | struct pt_regs *regs, void *cookie) | |
1681 | { | |
f6b76d4f ON |
1682 | struct sighand_struct *sighand = current->sighand; |
1683 | struct signal_struct *signal = current->signal; | |
1684 | int signr; | |
1da177e4 | 1685 | |
13b1c3d4 RM |
1686 | relock: |
1687 | /* | |
1688 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
1689 | * While in TASK_STOPPED, we were considered "frozen enough". | |
1690 | * Now that we woke up, it's crucial if we're supposed to be | |
1691 | * frozen that we freeze now before running anything substantial. | |
1692 | */ | |
fc558a74 RW |
1693 | try_to_freeze(); |
1694 | ||
f6b76d4f | 1695 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
1696 | /* |
1697 | * Every stopped thread goes here after wakeup. Check to see if | |
1698 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
1699 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
1700 | */ | |
f6b76d4f ON |
1701 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
1702 | int why = (signal->flags & SIGNAL_STOP_CONTINUED) | |
e4420551 | 1703 | ? CLD_CONTINUED : CLD_STOPPED; |
f6b76d4f ON |
1704 | signal->flags &= ~SIGNAL_CLD_MASK; |
1705 | spin_unlock_irq(&sighand->siglock); | |
e4420551 ON |
1706 | |
1707 | read_lock(&tasklist_lock); | |
1708 | do_notify_parent_cldstop(current->group_leader, why); | |
1709 | read_unlock(&tasklist_lock); | |
1710 | goto relock; | |
1711 | } | |
1712 | ||
1da177e4 LT |
1713 | for (;;) { |
1714 | struct k_sigaction *ka; | |
1715 | ||
f6b76d4f | 1716 | if (unlikely(signal->group_stop_count > 0) && |
f558b7e4 | 1717 | do_signal_stop(0)) |
1da177e4 LT |
1718 | goto relock; |
1719 | ||
f6b76d4f | 1720 | signr = dequeue_signal(current, ¤t->blocked, info); |
1da177e4 LT |
1721 | if (!signr) |
1722 | break; /* will return 0 */ | |
1723 | ||
18c98b65 RM |
1724 | if (signr != SIGKILL) { |
1725 | signr = ptrace_signal(signr, info, regs, cookie); | |
1726 | if (!signr) | |
1da177e4 | 1727 | continue; |
1da177e4 LT |
1728 | } |
1729 | ||
f6b76d4f | 1730 | ka = &sighand->action[signr-1]; |
1da177e4 LT |
1731 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
1732 | continue; | |
1733 | if (ka->sa.sa_handler != SIG_DFL) { | |
1734 | /* Run the handler. */ | |
1735 | *return_ka = *ka; | |
1736 | ||
1737 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1738 | ka->sa.sa_handler = SIG_DFL; | |
1739 | ||
1740 | break; /* will return non-zero "signr" value */ | |
1741 | } | |
1742 | ||
1743 | /* | |
1744 | * Now we are doing the default action for this signal. | |
1745 | */ | |
1746 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1747 | continue; | |
1748 | ||
84d73786 | 1749 | /* |
0fbc26a6 | 1750 | * Global init gets no signals it doesn't want. |
84d73786 | 1751 | */ |
0fbc26a6 | 1752 | if (is_global_init(current)) |
1da177e4 LT |
1753 | continue; |
1754 | ||
1755 | if (sig_kernel_stop(signr)) { | |
1756 | /* | |
1757 | * The default action is to stop all threads in | |
1758 | * the thread group. The job control signals | |
1759 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1760 | * always works. Note that siglock needs to be | |
1761 | * dropped during the call to is_orphaned_pgrp() | |
1762 | * because of lock ordering with tasklist_lock. | |
1763 | * This allows an intervening SIGCONT to be posted. | |
1764 | * We need to check for that and bail out if necessary. | |
1765 | */ | |
1766 | if (signr != SIGSTOP) { | |
f6b76d4f | 1767 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1768 | |
1769 | /* signals can be posted during this window */ | |
1770 | ||
3e7cd6c4 | 1771 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
1772 | goto relock; |
1773 | ||
f6b76d4f | 1774 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
1775 | } |
1776 | ||
1777 | if (likely(do_signal_stop(signr))) { | |
1778 | /* It released the siglock. */ | |
1779 | goto relock; | |
1780 | } | |
1781 | ||
1782 | /* | |
1783 | * We didn't actually stop, due to a race | |
1784 | * with SIGCONT or something like that. | |
1785 | */ | |
1786 | continue; | |
1787 | } | |
1788 | ||
f6b76d4f | 1789 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1790 | |
1791 | /* | |
1792 | * Anything else is fatal, maybe with a core dump. | |
1793 | */ | |
1794 | current->flags |= PF_SIGNALED; | |
2dce81bf | 1795 | |
1da177e4 | 1796 | if (sig_kernel_coredump(signr)) { |
2dce81bf ON |
1797 | if (print_fatal_signals) |
1798 | print_fatal_signal(regs, signr); | |
1da177e4 LT |
1799 | /* |
1800 | * If it was able to dump core, this kills all | |
1801 | * other threads in the group and synchronizes with | |
1802 | * their demise. If we lost the race with another | |
1803 | * thread getting here, it set group_exit_code | |
1804 | * first and our do_group_exit call below will use | |
1805 | * that value and ignore the one we pass it. | |
1806 | */ | |
1807 | do_coredump((long)signr, signr, regs); | |
1808 | } | |
1809 | ||
1810 | /* | |
1811 | * Death signals, no core dump. | |
1812 | */ | |
1813 | do_group_exit(signr); | |
1814 | /* NOTREACHED */ | |
1815 | } | |
f6b76d4f | 1816 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1817 | return signr; |
1818 | } | |
1819 | ||
d12619b5 ON |
1820 | void exit_signals(struct task_struct *tsk) |
1821 | { | |
1822 | int group_stop = 0; | |
5dee1707 | 1823 | struct task_struct *t; |
d12619b5 | 1824 | |
5dee1707 ON |
1825 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
1826 | tsk->flags |= PF_EXITING; | |
1827 | return; | |
d12619b5 ON |
1828 | } |
1829 | ||
5dee1707 | 1830 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
1831 | /* |
1832 | * From now this task is not visible for group-wide signals, | |
1833 | * see wants_signal(), do_signal_stop(). | |
1834 | */ | |
1835 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
1836 | if (!signal_pending(tsk)) |
1837 | goto out; | |
1838 | ||
1839 | /* It could be that __group_complete_signal() choose us to | |
1840 | * notify about group-wide signal. Another thread should be | |
1841 | * woken now to take the signal since we will not. | |
1842 | */ | |
1843 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
1844 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
1845 | recalc_sigpending_and_wake(t); | |
1846 | ||
1847 | if (unlikely(tsk->signal->group_stop_count) && | |
1848 | !--tsk->signal->group_stop_count) { | |
1849 | tsk->signal->flags = SIGNAL_STOP_STOPPED; | |
1850 | group_stop = 1; | |
1851 | } | |
1852 | out: | |
d12619b5 ON |
1853 | spin_unlock_irq(&tsk->sighand->siglock); |
1854 | ||
1855 | if (unlikely(group_stop)) { | |
1856 | read_lock(&tasklist_lock); | |
1857 | do_notify_parent_cldstop(tsk, CLD_STOPPED); | |
1858 | read_unlock(&tasklist_lock); | |
1859 | } | |
1860 | } | |
1861 | ||
1da177e4 LT |
1862 | EXPORT_SYMBOL(recalc_sigpending); |
1863 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
1864 | EXPORT_SYMBOL(flush_signals); | |
1865 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
1866 | EXPORT_SYMBOL(kill_proc); |
1867 | EXPORT_SYMBOL(ptrace_notify); | |
1868 | EXPORT_SYMBOL(send_sig); | |
1869 | EXPORT_SYMBOL(send_sig_info); | |
1870 | EXPORT_SYMBOL(sigprocmask); | |
1871 | EXPORT_SYMBOL(block_all_signals); | |
1872 | EXPORT_SYMBOL(unblock_all_signals); | |
1873 | ||
1874 | ||
1875 | /* | |
1876 | * System call entry points. | |
1877 | */ | |
1878 | ||
1879 | asmlinkage long sys_restart_syscall(void) | |
1880 | { | |
1881 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
1882 | return restart->fn(restart); | |
1883 | } | |
1884 | ||
1885 | long do_no_restart_syscall(struct restart_block *param) | |
1886 | { | |
1887 | return -EINTR; | |
1888 | } | |
1889 | ||
1890 | /* | |
1891 | * We don't need to get the kernel lock - this is all local to this | |
1892 | * particular thread.. (and that's good, because this is _heavily_ | |
1893 | * used by various programs) | |
1894 | */ | |
1895 | ||
1896 | /* | |
1897 | * This is also useful for kernel threads that want to temporarily | |
1898 | * (or permanently) block certain signals. | |
1899 | * | |
1900 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
1901 | * interface happily blocks "unblockable" signals like SIGKILL | |
1902 | * and friends. | |
1903 | */ | |
1904 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
1905 | { | |
1906 | int error; | |
1da177e4 LT |
1907 | |
1908 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
1909 | if (oldset) |
1910 | *oldset = current->blocked; | |
1911 | ||
1da177e4 LT |
1912 | error = 0; |
1913 | switch (how) { | |
1914 | case SIG_BLOCK: | |
1915 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
1916 | break; | |
1917 | case SIG_UNBLOCK: | |
1918 | signandsets(¤t->blocked, ¤t->blocked, set); | |
1919 | break; | |
1920 | case SIG_SETMASK: | |
1921 | current->blocked = *set; | |
1922 | break; | |
1923 | default: | |
1924 | error = -EINVAL; | |
1925 | } | |
1926 | recalc_sigpending(); | |
1927 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 1928 | |
1da177e4 LT |
1929 | return error; |
1930 | } | |
1931 | ||
1932 | asmlinkage long | |
1933 | sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize) | |
1934 | { | |
1935 | int error = -EINVAL; | |
1936 | sigset_t old_set, new_set; | |
1937 | ||
1938 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
1939 | if (sigsetsize != sizeof(sigset_t)) | |
1940 | goto out; | |
1941 | ||
1942 | if (set) { | |
1943 | error = -EFAULT; | |
1944 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
1945 | goto out; | |
1946 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
1947 | ||
1948 | error = sigprocmask(how, &new_set, &old_set); | |
1949 | if (error) | |
1950 | goto out; | |
1951 | if (oset) | |
1952 | goto set_old; | |
1953 | } else if (oset) { | |
1954 | spin_lock_irq(¤t->sighand->siglock); | |
1955 | old_set = current->blocked; | |
1956 | spin_unlock_irq(¤t->sighand->siglock); | |
1957 | ||
1958 | set_old: | |
1959 | error = -EFAULT; | |
1960 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
1961 | goto out; | |
1962 | } | |
1963 | error = 0; | |
1964 | out: | |
1965 | return error; | |
1966 | } | |
1967 | ||
1968 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
1969 | { | |
1970 | long error = -EINVAL; | |
1971 | sigset_t pending; | |
1972 | ||
1973 | if (sigsetsize > sizeof(sigset_t)) | |
1974 | goto out; | |
1975 | ||
1976 | spin_lock_irq(¤t->sighand->siglock); | |
1977 | sigorsets(&pending, ¤t->pending.signal, | |
1978 | ¤t->signal->shared_pending.signal); | |
1979 | spin_unlock_irq(¤t->sighand->siglock); | |
1980 | ||
1981 | /* Outside the lock because only this thread touches it. */ | |
1982 | sigandsets(&pending, ¤t->blocked, &pending); | |
1983 | ||
1984 | error = -EFAULT; | |
1985 | if (!copy_to_user(set, &pending, sigsetsize)) | |
1986 | error = 0; | |
1987 | ||
1988 | out: | |
1989 | return error; | |
1990 | } | |
1991 | ||
1992 | asmlinkage long | |
1993 | sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize) | |
1994 | { | |
1995 | return do_sigpending(set, sigsetsize); | |
1996 | } | |
1997 | ||
1998 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
1999 | ||
2000 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2001 | { | |
2002 | int err; | |
2003 | ||
2004 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2005 | return -EFAULT; | |
2006 | if (from->si_code < 0) | |
2007 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2008 | ? -EFAULT : 0; | |
2009 | /* | |
2010 | * If you change siginfo_t structure, please be sure | |
2011 | * this code is fixed accordingly. | |
fba2afaa DL |
2012 | * Please remember to update the signalfd_copyinfo() function |
2013 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2014 | * It should never copy any pad contained in the structure |
2015 | * to avoid security leaks, but must copy the generic | |
2016 | * 3 ints plus the relevant union member. | |
2017 | */ | |
2018 | err = __put_user(from->si_signo, &to->si_signo); | |
2019 | err |= __put_user(from->si_errno, &to->si_errno); | |
2020 | err |= __put_user((short)from->si_code, &to->si_code); | |
2021 | switch (from->si_code & __SI_MASK) { | |
2022 | case __SI_KILL: | |
2023 | err |= __put_user(from->si_pid, &to->si_pid); | |
2024 | err |= __put_user(from->si_uid, &to->si_uid); | |
2025 | break; | |
2026 | case __SI_TIMER: | |
2027 | err |= __put_user(from->si_tid, &to->si_tid); | |
2028 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2029 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2030 | break; | |
2031 | case __SI_POLL: | |
2032 | err |= __put_user(from->si_band, &to->si_band); | |
2033 | err |= __put_user(from->si_fd, &to->si_fd); | |
2034 | break; | |
2035 | case __SI_FAULT: | |
2036 | err |= __put_user(from->si_addr, &to->si_addr); | |
2037 | #ifdef __ARCH_SI_TRAPNO | |
2038 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
2039 | #endif | |
2040 | break; | |
2041 | case __SI_CHLD: | |
2042 | err |= __put_user(from->si_pid, &to->si_pid); | |
2043 | err |= __put_user(from->si_uid, &to->si_uid); | |
2044 | err |= __put_user(from->si_status, &to->si_status); | |
2045 | err |= __put_user(from->si_utime, &to->si_utime); | |
2046 | err |= __put_user(from->si_stime, &to->si_stime); | |
2047 | break; | |
2048 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2049 | case __SI_MESGQ: /* But this is */ | |
2050 | err |= __put_user(from->si_pid, &to->si_pid); | |
2051 | err |= __put_user(from->si_uid, &to->si_uid); | |
2052 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2053 | break; | |
2054 | default: /* this is just in case for now ... */ | |
2055 | err |= __put_user(from->si_pid, &to->si_pid); | |
2056 | err |= __put_user(from->si_uid, &to->si_uid); | |
2057 | break; | |
2058 | } | |
2059 | return err; | |
2060 | } | |
2061 | ||
2062 | #endif | |
2063 | ||
2064 | asmlinkage long | |
2065 | sys_rt_sigtimedwait(const sigset_t __user *uthese, | |
2066 | siginfo_t __user *uinfo, | |
2067 | const struct timespec __user *uts, | |
2068 | size_t sigsetsize) | |
2069 | { | |
2070 | int ret, sig; | |
2071 | sigset_t these; | |
2072 | struct timespec ts; | |
2073 | siginfo_t info; | |
2074 | long timeout = 0; | |
2075 | ||
2076 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2077 | if (sigsetsize != sizeof(sigset_t)) | |
2078 | return -EINVAL; | |
2079 | ||
2080 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2081 | return -EFAULT; | |
2082 | ||
2083 | /* | |
2084 | * Invert the set of allowed signals to get those we | |
2085 | * want to block. | |
2086 | */ | |
2087 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2088 | signotset(&these); | |
2089 | ||
2090 | if (uts) { | |
2091 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2092 | return -EFAULT; | |
2093 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2094 | || ts.tv_sec < 0) | |
2095 | return -EINVAL; | |
2096 | } | |
2097 | ||
2098 | spin_lock_irq(¤t->sighand->siglock); | |
2099 | sig = dequeue_signal(current, &these, &info); | |
2100 | if (!sig) { | |
2101 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2102 | if (uts) | |
2103 | timeout = (timespec_to_jiffies(&ts) | |
2104 | + (ts.tv_sec || ts.tv_nsec)); | |
2105 | ||
2106 | if (timeout) { | |
2107 | /* None ready -- temporarily unblock those we're | |
2108 | * interested while we are sleeping in so that we'll | |
2109 | * be awakened when they arrive. */ | |
2110 | current->real_blocked = current->blocked; | |
2111 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2112 | recalc_sigpending(); | |
2113 | spin_unlock_irq(¤t->sighand->siglock); | |
2114 | ||
75bcc8c5 | 2115 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2116 | |
1da177e4 LT |
2117 | spin_lock_irq(¤t->sighand->siglock); |
2118 | sig = dequeue_signal(current, &these, &info); | |
2119 | current->blocked = current->real_blocked; | |
2120 | siginitset(¤t->real_blocked, 0); | |
2121 | recalc_sigpending(); | |
2122 | } | |
2123 | } | |
2124 | spin_unlock_irq(¤t->sighand->siglock); | |
2125 | ||
2126 | if (sig) { | |
2127 | ret = sig; | |
2128 | if (uinfo) { | |
2129 | if (copy_siginfo_to_user(uinfo, &info)) | |
2130 | ret = -EFAULT; | |
2131 | } | |
2132 | } else { | |
2133 | ret = -EAGAIN; | |
2134 | if (timeout) | |
2135 | ret = -EINTR; | |
2136 | } | |
2137 | ||
2138 | return ret; | |
2139 | } | |
2140 | ||
2141 | asmlinkage long | |
2142 | sys_kill(int pid, int sig) | |
2143 | { | |
2144 | struct siginfo info; | |
2145 | ||
2146 | info.si_signo = sig; | |
2147 | info.si_errno = 0; | |
2148 | info.si_code = SI_USER; | |
b488893a | 2149 | info.si_pid = task_tgid_vnr(current); |
1da177e4 LT |
2150 | info.si_uid = current->uid; |
2151 | ||
2152 | return kill_something_info(sig, &info, pid); | |
2153 | } | |
2154 | ||
6dd69f10 | 2155 | static int do_tkill(int tgid, int pid, int sig) |
1da177e4 | 2156 | { |
1da177e4 | 2157 | int error; |
6dd69f10 | 2158 | struct siginfo info; |
1da177e4 | 2159 | struct task_struct *p; |
3547ff3a | 2160 | unsigned long flags; |
1da177e4 | 2161 | |
6dd69f10 | 2162 | error = -ESRCH; |
1da177e4 LT |
2163 | info.si_signo = sig; |
2164 | info.si_errno = 0; | |
2165 | info.si_code = SI_TKILL; | |
b488893a | 2166 | info.si_pid = task_tgid_vnr(current); |
1da177e4 LT |
2167 | info.si_uid = current->uid; |
2168 | ||
3547ff3a | 2169 | rcu_read_lock(); |
228ebcbe | 2170 | p = find_task_by_vpid(pid); |
b488893a | 2171 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
1da177e4 LT |
2172 | error = check_kill_permission(sig, &info, p); |
2173 | /* | |
2174 | * The null signal is a permissions and process existence | |
2175 | * probe. No signal is actually delivered. | |
3547ff3a ON |
2176 | * |
2177 | * If lock_task_sighand() fails we pretend the task dies | |
2178 | * after receiving the signal. The window is tiny, and the | |
2179 | * signal is private anyway. | |
1da177e4 | 2180 | */ |
3547ff3a | 2181 | if (!error && sig && lock_task_sighand(p, &flags)) { |
1da177e4 | 2182 | error = specific_send_sig_info(sig, &info, p); |
3547ff3a | 2183 | unlock_task_sighand(p, &flags); |
1da177e4 LT |
2184 | } |
2185 | } | |
3547ff3a | 2186 | rcu_read_unlock(); |
6dd69f10 | 2187 | |
1da177e4 LT |
2188 | return error; |
2189 | } | |
2190 | ||
6dd69f10 VL |
2191 | /** |
2192 | * sys_tgkill - send signal to one specific thread | |
2193 | * @tgid: the thread group ID of the thread | |
2194 | * @pid: the PID of the thread | |
2195 | * @sig: signal to be sent | |
2196 | * | |
72fd4a35 | 2197 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2198 | * exists but it's not belonging to the target process anymore. This |
2199 | * method solves the problem of threads exiting and PIDs getting reused. | |
2200 | */ | |
2201 | asmlinkage long sys_tgkill(int tgid, int pid, int sig) | |
2202 | { | |
2203 | /* This is only valid for single tasks */ | |
2204 | if (pid <= 0 || tgid <= 0) | |
2205 | return -EINVAL; | |
2206 | ||
2207 | return do_tkill(tgid, pid, sig); | |
2208 | } | |
2209 | ||
1da177e4 LT |
2210 | /* |
2211 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2212 | */ | |
2213 | asmlinkage long | |
2214 | sys_tkill(int pid, int sig) | |
2215 | { | |
1da177e4 LT |
2216 | /* This is only valid for single tasks */ |
2217 | if (pid <= 0) | |
2218 | return -EINVAL; | |
2219 | ||
6dd69f10 | 2220 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2221 | } |
2222 | ||
2223 | asmlinkage long | |
2224 | sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) | |
2225 | { | |
2226 | siginfo_t info; | |
2227 | ||
2228 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2229 | return -EFAULT; | |
2230 | ||
2231 | /* Not even root can pretend to send signals from the kernel. | |
2232 | Nor can they impersonate a kill(), which adds source info. */ | |
2233 | if (info.si_code >= 0) | |
2234 | return -EPERM; | |
2235 | info.si_signo = sig; | |
2236 | ||
2237 | /* POSIX.1b doesn't mention process groups. */ | |
2238 | return kill_proc_info(sig, &info, pid); | |
2239 | } | |
2240 | ||
88531f72 | 2241 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 2242 | { |
93585eea | 2243 | struct task_struct *t = current; |
1da177e4 | 2244 | struct k_sigaction *k; |
71fabd5e | 2245 | sigset_t mask; |
1da177e4 | 2246 | |
7ed20e1a | 2247 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2248 | return -EINVAL; |
2249 | ||
93585eea | 2250 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
2251 | |
2252 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2253 | if (oact) |
2254 | *oact = *k; | |
2255 | ||
2256 | if (act) { | |
9ac95f2f ON |
2257 | sigdelsetmask(&act->sa.sa_mask, |
2258 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2259 | *k = *act; |
1da177e4 LT |
2260 | /* |
2261 | * POSIX 3.3.1.3: | |
2262 | * "Setting a signal action to SIG_IGN for a signal that is | |
2263 | * pending shall cause the pending signal to be discarded, | |
2264 | * whether or not it is blocked." | |
2265 | * | |
2266 | * "Setting a signal action to SIG_DFL for a signal that is | |
2267 | * pending and whose default action is to ignore the signal | |
2268 | * (for example, SIGCHLD), shall cause the pending signal to | |
2269 | * be discarded, whether or not it is blocked" | |
2270 | */ | |
93585eea | 2271 | if (__sig_ignored(t, sig)) { |
71fabd5e GA |
2272 | sigemptyset(&mask); |
2273 | sigaddset(&mask, sig); | |
2274 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2275 | do { |
71fabd5e | 2276 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2277 | t = next_thread(t); |
2278 | } while (t != current); | |
1da177e4 | 2279 | } |
1da177e4 LT |
2280 | } |
2281 | ||
2282 | spin_unlock_irq(¤t->sighand->siglock); | |
2283 | return 0; | |
2284 | } | |
2285 | ||
2286 | int | |
2287 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2288 | { | |
2289 | stack_t oss; | |
2290 | int error; | |
2291 | ||
2292 | if (uoss) { | |
2293 | oss.ss_sp = (void __user *) current->sas_ss_sp; | |
2294 | oss.ss_size = current->sas_ss_size; | |
2295 | oss.ss_flags = sas_ss_flags(sp); | |
2296 | } | |
2297 | ||
2298 | if (uss) { | |
2299 | void __user *ss_sp; | |
2300 | size_t ss_size; | |
2301 | int ss_flags; | |
2302 | ||
2303 | error = -EFAULT; | |
2304 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss)) | |
2305 | || __get_user(ss_sp, &uss->ss_sp) | |
2306 | || __get_user(ss_flags, &uss->ss_flags) | |
2307 | || __get_user(ss_size, &uss->ss_size)) | |
2308 | goto out; | |
2309 | ||
2310 | error = -EPERM; | |
2311 | if (on_sig_stack(sp)) | |
2312 | goto out; | |
2313 | ||
2314 | error = -EINVAL; | |
2315 | /* | |
2316 | * | |
2317 | * Note - this code used to test ss_flags incorrectly | |
2318 | * old code may have been written using ss_flags==0 | |
2319 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2320 | * way that worked) - this fix preserves that older | |
2321 | * mechanism | |
2322 | */ | |
2323 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2324 | goto out; | |
2325 | ||
2326 | if (ss_flags == SS_DISABLE) { | |
2327 | ss_size = 0; | |
2328 | ss_sp = NULL; | |
2329 | } else { | |
2330 | error = -ENOMEM; | |
2331 | if (ss_size < MINSIGSTKSZ) | |
2332 | goto out; | |
2333 | } | |
2334 | ||
2335 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2336 | current->sas_ss_size = ss_size; | |
2337 | } | |
2338 | ||
2339 | if (uoss) { | |
2340 | error = -EFAULT; | |
2341 | if (copy_to_user(uoss, &oss, sizeof(oss))) | |
2342 | goto out; | |
2343 | } | |
2344 | ||
2345 | error = 0; | |
2346 | out: | |
2347 | return error; | |
2348 | } | |
2349 | ||
2350 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2351 | ||
2352 | asmlinkage long | |
2353 | sys_sigpending(old_sigset_t __user *set) | |
2354 | { | |
2355 | return do_sigpending(set, sizeof(*set)); | |
2356 | } | |
2357 | ||
2358 | #endif | |
2359 | ||
2360 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2361 | /* Some platforms have their own version with special arguments others | |
2362 | support only sys_rt_sigprocmask. */ | |
2363 | ||
2364 | asmlinkage long | |
2365 | sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset) | |
2366 | { | |
2367 | int error; | |
2368 | old_sigset_t old_set, new_set; | |
2369 | ||
2370 | if (set) { | |
2371 | error = -EFAULT; | |
2372 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2373 | goto out; | |
2374 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2375 | ||
2376 | spin_lock_irq(¤t->sighand->siglock); | |
2377 | old_set = current->blocked.sig[0]; | |
2378 | ||
2379 | error = 0; | |
2380 | switch (how) { | |
2381 | default: | |
2382 | error = -EINVAL; | |
2383 | break; | |
2384 | case SIG_BLOCK: | |
2385 | sigaddsetmask(¤t->blocked, new_set); | |
2386 | break; | |
2387 | case SIG_UNBLOCK: | |
2388 | sigdelsetmask(¤t->blocked, new_set); | |
2389 | break; | |
2390 | case SIG_SETMASK: | |
2391 | current->blocked.sig[0] = new_set; | |
2392 | break; | |
2393 | } | |
2394 | ||
2395 | recalc_sigpending(); | |
2396 | spin_unlock_irq(¤t->sighand->siglock); | |
2397 | if (error) | |
2398 | goto out; | |
2399 | if (oset) | |
2400 | goto set_old; | |
2401 | } else if (oset) { | |
2402 | old_set = current->blocked.sig[0]; | |
2403 | set_old: | |
2404 | error = -EFAULT; | |
2405 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2406 | goto out; | |
2407 | } | |
2408 | error = 0; | |
2409 | out: | |
2410 | return error; | |
2411 | } | |
2412 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2413 | ||
2414 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
2415 | asmlinkage long | |
2416 | sys_rt_sigaction(int sig, | |
2417 | const struct sigaction __user *act, | |
2418 | struct sigaction __user *oact, | |
2419 | size_t sigsetsize) | |
2420 | { | |
2421 | struct k_sigaction new_sa, old_sa; | |
2422 | int ret = -EINVAL; | |
2423 | ||
2424 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2425 | if (sigsetsize != sizeof(sigset_t)) | |
2426 | goto out; | |
2427 | ||
2428 | if (act) { | |
2429 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2430 | return -EFAULT; | |
2431 | } | |
2432 | ||
2433 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2434 | ||
2435 | if (!ret && oact) { | |
2436 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2437 | return -EFAULT; | |
2438 | } | |
2439 | out: | |
2440 | return ret; | |
2441 | } | |
2442 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2443 | ||
2444 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2445 | ||
2446 | /* | |
2447 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2448 | */ | |
2449 | asmlinkage long | |
2450 | sys_sgetmask(void) | |
2451 | { | |
2452 | /* SMP safe */ | |
2453 | return current->blocked.sig[0]; | |
2454 | } | |
2455 | ||
2456 | asmlinkage long | |
2457 | sys_ssetmask(int newmask) | |
2458 | { | |
2459 | int old; | |
2460 | ||
2461 | spin_lock_irq(¤t->sighand->siglock); | |
2462 | old = current->blocked.sig[0]; | |
2463 | ||
2464 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2465 | sigmask(SIGSTOP))); | |
2466 | recalc_sigpending(); | |
2467 | spin_unlock_irq(¤t->sighand->siglock); | |
2468 | ||
2469 | return old; | |
2470 | } | |
2471 | #endif /* __ARCH_WANT_SGETMASK */ | |
2472 | ||
2473 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2474 | /* | |
2475 | * For backwards compatibility. Functionality superseded by sigaction. | |
2476 | */ | |
2477 | asmlinkage unsigned long | |
2478 | sys_signal(int sig, __sighandler_t handler) | |
2479 | { | |
2480 | struct k_sigaction new_sa, old_sa; | |
2481 | int ret; | |
2482 | ||
2483 | new_sa.sa.sa_handler = handler; | |
2484 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2485 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2486 | |
2487 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2488 | ||
2489 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2490 | } | |
2491 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2492 | ||
2493 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2494 | ||
2495 | asmlinkage long | |
2496 | sys_pause(void) | |
2497 | { | |
2498 | current->state = TASK_INTERRUPTIBLE; | |
2499 | schedule(); | |
2500 | return -ERESTARTNOHAND; | |
2501 | } | |
2502 | ||
2503 | #endif | |
2504 | ||
150256d8 DW |
2505 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
2506 | asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize) | |
2507 | { | |
2508 | sigset_t newset; | |
2509 | ||
2510 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2511 | if (sigsetsize != sizeof(sigset_t)) | |
2512 | return -EINVAL; | |
2513 | ||
2514 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2515 | return -EFAULT; | |
2516 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2517 | ||
2518 | spin_lock_irq(¤t->sighand->siglock); | |
2519 | current->saved_sigmask = current->blocked; | |
2520 | current->blocked = newset; | |
2521 | recalc_sigpending(); | |
2522 | spin_unlock_irq(¤t->sighand->siglock); | |
2523 | ||
2524 | current->state = TASK_INTERRUPTIBLE; | |
2525 | schedule(); | |
2526 | set_thread_flag(TIF_RESTORE_SIGMASK); | |
2527 | return -ERESTARTNOHAND; | |
2528 | } | |
2529 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2530 | ||
f269fdd1 DH |
2531 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2532 | { | |
2533 | return NULL; | |
2534 | } | |
2535 | ||
1da177e4 LT |
2536 | void __init signals_init(void) |
2537 | { | |
0a31bd5f | 2538 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2539 | } |