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> |
35de254d | 25 | #include <linux/tracehook.h> |
c59ede7b | 26 | #include <linux/capability.h> |
7dfb7103 | 27 | #include <linux/freezer.h> |
84d73786 SB |
28 | #include <linux/pid_namespace.h> |
29 | #include <linux/nsproxy.h> | |
0a16b607 | 30 | #include <trace/sched.h> |
84d73786 | 31 | |
1da177e4 LT |
32 | #include <asm/param.h> |
33 | #include <asm/uaccess.h> | |
34 | #include <asm/unistd.h> | |
35 | #include <asm/siginfo.h> | |
e1396065 | 36 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
37 | |
38 | /* | |
39 | * SLAB caches for signal bits. | |
40 | */ | |
41 | ||
e18b890b | 42 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 43 | |
7e066fb8 MD |
44 | DEFINE_TRACE(sched_signal_send); |
45 | ||
35de254d | 46 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 47 | { |
35de254d RM |
48 | return t->sighand->action[sig - 1].sa.sa_handler; |
49 | } | |
93585eea | 50 | |
35de254d RM |
51 | static int sig_handler_ignored(void __user *handler, int sig) |
52 | { | |
93585eea | 53 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
54 | return handler == SIG_IGN || |
55 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
56 | } | |
1da177e4 LT |
57 | |
58 | static int sig_ignored(struct task_struct *t, int sig) | |
59 | { | |
35de254d | 60 | void __user *handler; |
1da177e4 LT |
61 | |
62 | /* | |
63 | * Blocked signals are never ignored, since the | |
64 | * signal handler may change by the time it is | |
65 | * unblocked. | |
66 | */ | |
325d22df | 67 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
68 | return 0; |
69 | ||
35de254d RM |
70 | handler = sig_handler(t, sig); |
71 | if (!sig_handler_ignored(handler, sig)) | |
72 | return 0; | |
73 | ||
74 | /* | |
75 | * Tracers may want to know about even ignored signals. | |
76 | */ | |
77 | return !tracehook_consider_ignored_signal(t, sig, handler); | |
1da177e4 LT |
78 | } |
79 | ||
80 | /* | |
81 | * Re-calculate pending state from the set of locally pending | |
82 | * signals, globally pending signals, and blocked signals. | |
83 | */ | |
84 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
85 | { | |
86 | unsigned long ready; | |
87 | long i; | |
88 | ||
89 | switch (_NSIG_WORDS) { | |
90 | default: | |
91 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
92 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
93 | break; | |
94 | ||
95 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
96 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
97 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
98 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
99 | break; | |
100 | ||
101 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
102 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
103 | break; | |
104 | ||
105 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
106 | } | |
107 | return ready != 0; | |
108 | } | |
109 | ||
110 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
111 | ||
7bb44ade | 112 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 LT |
113 | { |
114 | if (t->signal->group_stop_count > 0 || | |
115 | PENDING(&t->pending, &t->blocked) || | |
7bb44ade | 116 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 117 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
118 | return 1; |
119 | } | |
b74d0deb RM |
120 | /* |
121 | * We must never clear the flag in another thread, or in current | |
122 | * when it's possible the current syscall is returning -ERESTART*. | |
123 | * So we don't clear it here, and only callers who know they should do. | |
124 | */ | |
7bb44ade RM |
125 | return 0; |
126 | } | |
127 | ||
128 | /* | |
129 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
130 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
131 | */ | |
132 | void recalc_sigpending_and_wake(struct task_struct *t) | |
133 | { | |
134 | if (recalc_sigpending_tsk(t)) | |
135 | signal_wake_up(t, 0); | |
1da177e4 LT |
136 | } |
137 | ||
138 | void recalc_sigpending(void) | |
139 | { | |
b787f7ba RM |
140 | if (unlikely(tracehook_force_sigpending())) |
141 | set_thread_flag(TIF_SIGPENDING); | |
142 | else if (!recalc_sigpending_tsk(current) && !freezing(current)) | |
b74d0deb RM |
143 | clear_thread_flag(TIF_SIGPENDING); |
144 | ||
1da177e4 LT |
145 | } |
146 | ||
147 | /* Given the mask, find the first available signal that should be serviced. */ | |
148 | ||
fba2afaa | 149 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
150 | { |
151 | unsigned long i, *s, *m, x; | |
152 | int sig = 0; | |
153 | ||
154 | s = pending->signal.sig; | |
155 | m = mask->sig; | |
156 | switch (_NSIG_WORDS) { | |
157 | default: | |
158 | for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m) | |
159 | if ((x = *s &~ *m) != 0) { | |
160 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
161 | break; | |
162 | } | |
163 | break; | |
164 | ||
165 | case 2: if ((x = s[0] &~ m[0]) != 0) | |
166 | sig = 1; | |
167 | else if ((x = s[1] &~ m[1]) != 0) | |
168 | sig = _NSIG_BPW + 1; | |
169 | else | |
170 | break; | |
171 | sig += ffz(~x); | |
172 | break; | |
173 | ||
174 | case 1: if ((x = *s &~ *m) != 0) | |
175 | sig = ffz(~x) + 1; | |
176 | break; | |
177 | } | |
178 | ||
179 | return sig; | |
180 | } | |
181 | ||
c69e8d9c DH |
182 | /* |
183 | * allocate a new signal queue record | |
184 | * - this may be called without locks if and only if t == current, otherwise an | |
d84f4f99 | 185 | * appopriate lock must be held to stop the target task from exiting |
c69e8d9c | 186 | */ |
dd0fc66f | 187 | static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, |
1da177e4 LT |
188 | int override_rlimit) |
189 | { | |
190 | struct sigqueue *q = NULL; | |
10b1fbdb | 191 | struct user_struct *user; |
1da177e4 | 192 | |
10b1fbdb | 193 | /* |
c69e8d9c DH |
194 | * We won't get problems with the target's UID changing under us |
195 | * because changing it requires RCU be used, and if t != current, the | |
196 | * caller must be holding the RCU readlock (by way of a spinlock) and | |
197 | * we use RCU protection here | |
10b1fbdb | 198 | */ |
d84f4f99 | 199 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 200 | atomic_inc(&user->sigpending); |
1da177e4 | 201 | if (override_rlimit || |
10b1fbdb | 202 | atomic_read(&user->sigpending) <= |
1da177e4 LT |
203 | t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) |
204 | q = kmem_cache_alloc(sigqueue_cachep, flags); | |
205 | if (unlikely(q == NULL)) { | |
10b1fbdb | 206 | atomic_dec(&user->sigpending); |
d84f4f99 | 207 | free_uid(user); |
1da177e4 LT |
208 | } else { |
209 | INIT_LIST_HEAD(&q->list); | |
210 | q->flags = 0; | |
d84f4f99 | 211 | q->user = user; |
1da177e4 | 212 | } |
d84f4f99 DH |
213 | |
214 | return q; | |
1da177e4 LT |
215 | } |
216 | ||
514a01b8 | 217 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
218 | { |
219 | if (q->flags & SIGQUEUE_PREALLOC) | |
220 | return; | |
221 | atomic_dec(&q->user->sigpending); | |
222 | free_uid(q->user); | |
223 | kmem_cache_free(sigqueue_cachep, q); | |
224 | } | |
225 | ||
6a14c5c9 | 226 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
227 | { |
228 | struct sigqueue *q; | |
229 | ||
230 | sigemptyset(&queue->signal); | |
231 | while (!list_empty(&queue->list)) { | |
232 | q = list_entry(queue->list.next, struct sigqueue , list); | |
233 | list_del_init(&q->list); | |
234 | __sigqueue_free(q); | |
235 | } | |
236 | } | |
237 | ||
238 | /* | |
239 | * Flush all pending signals for a task. | |
240 | */ | |
c81addc9 | 241 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
242 | { |
243 | unsigned long flags; | |
244 | ||
245 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
f5264481 | 246 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 LT |
247 | flush_sigqueue(&t->pending); |
248 | flush_sigqueue(&t->signal->shared_pending); | |
249 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
250 | } | |
251 | ||
cbaffba1 ON |
252 | static void __flush_itimer_signals(struct sigpending *pending) |
253 | { | |
254 | sigset_t signal, retain; | |
255 | struct sigqueue *q, *n; | |
256 | ||
257 | signal = pending->signal; | |
258 | sigemptyset(&retain); | |
259 | ||
260 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
261 | int sig = q->info.si_signo; | |
262 | ||
263 | if (likely(q->info.si_code != SI_TIMER)) { | |
264 | sigaddset(&retain, sig); | |
265 | } else { | |
266 | sigdelset(&signal, sig); | |
267 | list_del_init(&q->list); | |
268 | __sigqueue_free(q); | |
269 | } | |
270 | } | |
271 | ||
272 | sigorsets(&pending->signal, &signal, &retain); | |
273 | } | |
274 | ||
275 | void flush_itimer_signals(void) | |
276 | { | |
277 | struct task_struct *tsk = current; | |
278 | unsigned long flags; | |
279 | ||
280 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
281 | __flush_itimer_signals(&tsk->pending); | |
282 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
283 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
284 | } | |
285 | ||
10ab825b ON |
286 | void ignore_signals(struct task_struct *t) |
287 | { | |
288 | int i; | |
289 | ||
290 | for (i = 0; i < _NSIG; ++i) | |
291 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
292 | ||
293 | flush_signals(t); | |
294 | } | |
295 | ||
1da177e4 LT |
296 | /* |
297 | * Flush all handlers for a task. | |
298 | */ | |
299 | ||
300 | void | |
301 | flush_signal_handlers(struct task_struct *t, int force_default) | |
302 | { | |
303 | int i; | |
304 | struct k_sigaction *ka = &t->sighand->action[0]; | |
305 | for (i = _NSIG ; i != 0 ; i--) { | |
306 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
307 | ka->sa.sa_handler = SIG_DFL; | |
308 | ka->sa.sa_flags = 0; | |
309 | sigemptyset(&ka->sa.sa_mask); | |
310 | ka++; | |
311 | } | |
312 | } | |
313 | ||
abd4f750 MAS |
314 | int unhandled_signal(struct task_struct *tsk, int sig) |
315 | { | |
445a91d2 | 316 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 317 | if (is_global_init(tsk)) |
abd4f750 | 318 | return 1; |
445a91d2 | 319 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 320 | return 0; |
445a91d2 | 321 | return !tracehook_consider_fatal_signal(tsk, sig, handler); |
abd4f750 MAS |
322 | } |
323 | ||
1da177e4 LT |
324 | |
325 | /* Notify the system that a driver wants to block all signals for this | |
326 | * process, and wants to be notified if any signals at all were to be | |
327 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
328 | * signal will be acted upon after all. If the notifier routine returns 0, | |
329 | * then then signal will be blocked. Only one block per process is | |
330 | * allowed. priv is a pointer to private data that the notifier routine | |
331 | * can use to determine if the signal should be blocked or not. */ | |
332 | ||
333 | void | |
334 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
335 | { | |
336 | unsigned long flags; | |
337 | ||
338 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
339 | current->notifier_mask = mask; | |
340 | current->notifier_data = priv; | |
341 | current->notifier = notifier; | |
342 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
343 | } | |
344 | ||
345 | /* Notify the system that blocking has ended. */ | |
346 | ||
347 | void | |
348 | unblock_all_signals(void) | |
349 | { | |
350 | unsigned long flags; | |
351 | ||
352 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
353 | current->notifier = NULL; | |
354 | current->notifier_data = NULL; | |
355 | recalc_sigpending(); | |
356 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
357 | } | |
358 | ||
100360f0 | 359 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
360 | { |
361 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 362 | |
1da177e4 LT |
363 | /* |
364 | * Collect the siginfo appropriate to this signal. Check if | |
365 | * there is another siginfo for the same signal. | |
366 | */ | |
367 | list_for_each_entry(q, &list->list, list) { | |
368 | if (q->info.si_signo == sig) { | |
d4434207 ON |
369 | if (first) |
370 | goto still_pending; | |
1da177e4 LT |
371 | first = q; |
372 | } | |
373 | } | |
d4434207 ON |
374 | |
375 | sigdelset(&list->signal, sig); | |
376 | ||
1da177e4 | 377 | if (first) { |
d4434207 | 378 | still_pending: |
1da177e4 LT |
379 | list_del_init(&first->list); |
380 | copy_siginfo(info, &first->info); | |
381 | __sigqueue_free(first); | |
1da177e4 | 382 | } else { |
1da177e4 LT |
383 | /* Ok, it wasn't in the queue. This must be |
384 | a fast-pathed signal or we must have been | |
385 | out of queue space. So zero out the info. | |
386 | */ | |
1da177e4 LT |
387 | info->si_signo = sig; |
388 | info->si_errno = 0; | |
389 | info->si_code = 0; | |
390 | info->si_pid = 0; | |
391 | info->si_uid = 0; | |
392 | } | |
1da177e4 LT |
393 | } |
394 | ||
395 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
396 | siginfo_t *info) | |
397 | { | |
27d91e07 | 398 | int sig = next_signal(pending, mask); |
1da177e4 | 399 | |
1da177e4 LT |
400 | if (sig) { |
401 | if (current->notifier) { | |
402 | if (sigismember(current->notifier_mask, sig)) { | |
403 | if (!(current->notifier)(current->notifier_data)) { | |
404 | clear_thread_flag(TIF_SIGPENDING); | |
405 | return 0; | |
406 | } | |
407 | } | |
408 | } | |
409 | ||
100360f0 | 410 | collect_signal(sig, pending, info); |
1da177e4 | 411 | } |
1da177e4 LT |
412 | |
413 | return sig; | |
414 | } | |
415 | ||
416 | /* | |
417 | * Dequeue a signal and return the element to the caller, which is | |
418 | * expected to free it. | |
419 | * | |
420 | * All callers have to hold the siglock. | |
421 | */ | |
422 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
423 | { | |
c5363d03 | 424 | int signr; |
caec4e8d BH |
425 | |
426 | /* We only dequeue private signals from ourselves, we don't let | |
427 | * signalfd steal them | |
428 | */ | |
b8fceee1 | 429 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 430 | if (!signr) { |
1da177e4 LT |
431 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
432 | mask, info); | |
8bfd9a7a TG |
433 | /* |
434 | * itimer signal ? | |
435 | * | |
436 | * itimers are process shared and we restart periodic | |
437 | * itimers in the signal delivery path to prevent DoS | |
438 | * attacks in the high resolution timer case. This is | |
439 | * compliant with the old way of self restarting | |
440 | * itimers, as the SIGALRM is a legacy signal and only | |
441 | * queued once. Changing the restart behaviour to | |
442 | * restart the timer in the signal dequeue path is | |
443 | * reducing the timer noise on heavy loaded !highres | |
444 | * systems too. | |
445 | */ | |
446 | if (unlikely(signr == SIGALRM)) { | |
447 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
448 | ||
449 | if (!hrtimer_is_queued(tmr) && | |
450 | tsk->signal->it_real_incr.tv64 != 0) { | |
451 | hrtimer_forward(tmr, tmr->base->get_time(), | |
452 | tsk->signal->it_real_incr); | |
453 | hrtimer_restart(tmr); | |
454 | } | |
455 | } | |
456 | } | |
c5363d03 | 457 | |
b8fceee1 | 458 | recalc_sigpending(); |
c5363d03 PE |
459 | if (!signr) |
460 | return 0; | |
461 | ||
462 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
463 | /* |
464 | * Set a marker that we have dequeued a stop signal. Our | |
465 | * caller might release the siglock and then the pending | |
466 | * stop signal it is about to process is no longer in the | |
467 | * pending bitmasks, but must still be cleared by a SIGCONT | |
468 | * (and overruled by a SIGKILL). So those cases clear this | |
469 | * shared flag after we've set it. Note that this flag may | |
470 | * remain set after the signal we return is ignored or | |
471 | * handled. That doesn't matter because its only purpose | |
472 | * is to alert stop-signal processing code when another | |
473 | * processor has come along and cleared the flag. | |
474 | */ | |
92413d77 | 475 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; |
8bfd9a7a | 476 | } |
c5363d03 | 477 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
478 | /* |
479 | * Release the siglock to ensure proper locking order | |
480 | * of timer locks outside of siglocks. Note, we leave | |
481 | * irqs disabled here, since the posix-timers code is | |
482 | * about to disable them again anyway. | |
483 | */ | |
484 | spin_unlock(&tsk->sighand->siglock); | |
485 | do_schedule_next_timer(info); | |
486 | spin_lock(&tsk->sighand->siglock); | |
487 | } | |
488 | return signr; | |
489 | } | |
490 | ||
491 | /* | |
492 | * Tell a process that it has a new active signal.. | |
493 | * | |
494 | * NOTE! we rely on the previous spin_lock to | |
495 | * lock interrupts for us! We can only be called with | |
496 | * "siglock" held, and the local interrupt must | |
497 | * have been disabled when that got acquired! | |
498 | * | |
499 | * No need to set need_resched since signal event passing | |
500 | * goes through ->blocked | |
501 | */ | |
502 | void signal_wake_up(struct task_struct *t, int resume) | |
503 | { | |
504 | unsigned int mask; | |
505 | ||
506 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
507 | ||
508 | /* | |
f021a3c2 MW |
509 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
510 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
511 | * executing another processor and just now entering stopped state. |
512 | * By using wake_up_state, we ensure the process will wake up and | |
513 | * handle its death signal. | |
514 | */ | |
515 | mask = TASK_INTERRUPTIBLE; | |
516 | if (resume) | |
f021a3c2 | 517 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
518 | if (!wake_up_state(t, mask)) |
519 | kick_process(t); | |
520 | } | |
521 | ||
71fabd5e GA |
522 | /* |
523 | * Remove signals in mask from the pending set and queue. | |
524 | * Returns 1 if any signals were found. | |
525 | * | |
526 | * All callers must be holding the siglock. | |
527 | * | |
528 | * This version takes a sigset mask and looks at all signals, | |
529 | * not just those in the first mask word. | |
530 | */ | |
531 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
532 | { | |
533 | struct sigqueue *q, *n; | |
534 | sigset_t m; | |
535 | ||
536 | sigandsets(&m, mask, &s->signal); | |
537 | if (sigisemptyset(&m)) | |
538 | return 0; | |
539 | ||
540 | signandsets(&s->signal, &s->signal, mask); | |
541 | list_for_each_entry_safe(q, n, &s->list, list) { | |
542 | if (sigismember(mask, q->info.si_signo)) { | |
543 | list_del_init(&q->list); | |
544 | __sigqueue_free(q); | |
545 | } | |
546 | } | |
547 | return 1; | |
548 | } | |
1da177e4 LT |
549 | /* |
550 | * Remove signals in mask from the pending set and queue. | |
551 | * Returns 1 if any signals were found. | |
552 | * | |
553 | * All callers must be holding the siglock. | |
554 | */ | |
555 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
556 | { | |
557 | struct sigqueue *q, *n; | |
558 | ||
559 | if (!sigtestsetmask(&s->signal, mask)) | |
560 | return 0; | |
561 | ||
562 | sigdelsetmask(&s->signal, mask); | |
563 | list_for_each_entry_safe(q, n, &s->list, list) { | |
564 | if (q->info.si_signo < SIGRTMIN && | |
565 | (mask & sigmask(q->info.si_signo))) { | |
566 | list_del_init(&q->list); | |
567 | __sigqueue_free(q); | |
568 | } | |
569 | } | |
570 | return 1; | |
571 | } | |
572 | ||
573 | /* | |
574 | * Bad permissions for sending the signal | |
c69e8d9c | 575 | * - the caller must hold at least the RCU read lock |
1da177e4 LT |
576 | */ |
577 | static int check_kill_permission(int sig, struct siginfo *info, | |
578 | struct task_struct *t) | |
579 | { | |
c69e8d9c | 580 | const struct cred *cred = current_cred(), *tcred; |
2e2ba22e | 581 | struct pid *sid; |
3b5e9e53 ON |
582 | int error; |
583 | ||
7ed20e1a | 584 | if (!valid_signal(sig)) |
3b5e9e53 ON |
585 | return -EINVAL; |
586 | ||
587 | if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info))) | |
588 | return 0; | |
e54dc243 | 589 | |
3b5e9e53 ON |
590 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
591 | if (error) | |
1da177e4 | 592 | return error; |
3b5e9e53 | 593 | |
c69e8d9c DH |
594 | tcred = __task_cred(t); |
595 | if ((cred->euid ^ tcred->suid) && | |
596 | (cred->euid ^ tcred->uid) && | |
597 | (cred->uid ^ tcred->suid) && | |
598 | (cred->uid ^ tcred->uid) && | |
2e2ba22e ON |
599 | !capable(CAP_KILL)) { |
600 | switch (sig) { | |
601 | case SIGCONT: | |
2e2ba22e | 602 | sid = task_session(t); |
2e2ba22e ON |
603 | /* |
604 | * We don't return the error if sid == NULL. The | |
605 | * task was unhashed, the caller must notice this. | |
606 | */ | |
607 | if (!sid || sid == task_session(current)) | |
608 | break; | |
609 | default: | |
610 | return -EPERM; | |
611 | } | |
612 | } | |
c2f0c7c3 | 613 | |
e54dc243 | 614 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
615 | } |
616 | ||
1da177e4 | 617 | /* |
7e695a5e ON |
618 | * Handle magic process-wide effects of stop/continue signals. Unlike |
619 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
620 | * time regardless of blocking, ignoring, or handling. This does the |
621 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
622 | * signals. The process stop is done as a signal action for SIG_DFL. |
623 | * | |
624 | * Returns true if the signal should be actually delivered, otherwise | |
625 | * it should be dropped. | |
1da177e4 | 626 | */ |
7e695a5e | 627 | static int prepare_signal(int sig, struct task_struct *p) |
1da177e4 | 628 | { |
ad16a460 | 629 | struct signal_struct *signal = p->signal; |
1da177e4 LT |
630 | struct task_struct *t; |
631 | ||
7e695a5e | 632 | if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) { |
1da177e4 | 633 | /* |
7e695a5e | 634 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 635 | */ |
7e695a5e | 636 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
637 | /* |
638 | * This is a stop signal. Remove SIGCONT from all queues. | |
639 | */ | |
ad16a460 | 640 | rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); |
1da177e4 LT |
641 | t = p; |
642 | do { | |
643 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
ad16a460 | 644 | } while_each_thread(p, t); |
1da177e4 | 645 | } else if (sig == SIGCONT) { |
fc321d2e | 646 | unsigned int why; |
1da177e4 LT |
647 | /* |
648 | * Remove all stop signals from all queues, | |
649 | * and wake all threads. | |
650 | */ | |
ad16a460 | 651 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
652 | t = p; |
653 | do { | |
654 | unsigned int state; | |
655 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
1da177e4 LT |
656 | /* |
657 | * If there is a handler for SIGCONT, we must make | |
658 | * sure that no thread returns to user mode before | |
659 | * we post the signal, in case it was the only | |
660 | * thread eligible to run the signal handler--then | |
661 | * it must not do anything between resuming and | |
662 | * running the handler. With the TIF_SIGPENDING | |
663 | * flag set, the thread will pause and acquire the | |
664 | * siglock that we hold now and until we've queued | |
fc321d2e | 665 | * the pending signal. |
1da177e4 LT |
666 | * |
667 | * Wake up the stopped thread _after_ setting | |
668 | * TIF_SIGPENDING | |
669 | */ | |
f021a3c2 | 670 | state = __TASK_STOPPED; |
1da177e4 LT |
671 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { |
672 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
673 | state |= TASK_INTERRUPTIBLE; | |
674 | } | |
675 | wake_up_state(t, state); | |
ad16a460 | 676 | } while_each_thread(p, t); |
1da177e4 | 677 | |
fc321d2e ON |
678 | /* |
679 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
680 | * | |
681 | * If we were in the middle of a group stop, we pretend it | |
682 | * was already finished, and then continued. Since SIGCHLD | |
683 | * doesn't queue we report only CLD_STOPPED, as if the next | |
684 | * CLD_CONTINUED was dropped. | |
685 | */ | |
686 | why = 0; | |
ad16a460 | 687 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 688 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 689 | else if (signal->group_stop_count) |
fc321d2e ON |
690 | why |= SIGNAL_CLD_STOPPED; |
691 | ||
692 | if (why) { | |
021e1ae3 ON |
693 | /* |
694 | * The first thread which returns from finish_stop() | |
695 | * will take ->siglock, notice SIGNAL_CLD_MASK, and | |
696 | * notify its parent. See get_signal_to_deliver(). | |
697 | */ | |
ad16a460 ON |
698 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
699 | signal->group_stop_count = 0; | |
700 | signal->group_exit_code = 0; | |
1da177e4 LT |
701 | } else { |
702 | /* | |
703 | * We are not stopped, but there could be a stop | |
704 | * signal in the middle of being processed after | |
705 | * being removed from the queue. Clear that too. | |
706 | */ | |
ad16a460 | 707 | signal->flags &= ~SIGNAL_STOP_DEQUEUED; |
1da177e4 | 708 | } |
1da177e4 | 709 | } |
7e695a5e ON |
710 | |
711 | return !sig_ignored(p, sig); | |
1da177e4 LT |
712 | } |
713 | ||
71f11dc0 ON |
714 | /* |
715 | * Test if P wants to take SIG. After we've checked all threads with this, | |
716 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
717 | * blocking SIG were ruled out because they are not running and already | |
718 | * have pending signals. Such threads will dequeue from the shared queue | |
719 | * as soon as they're available, so putting the signal on the shared queue | |
720 | * will be equivalent to sending it to one such thread. | |
721 | */ | |
722 | static inline int wants_signal(int sig, struct task_struct *p) | |
723 | { | |
724 | if (sigismember(&p->blocked, sig)) | |
725 | return 0; | |
726 | if (p->flags & PF_EXITING) | |
727 | return 0; | |
728 | if (sig == SIGKILL) | |
729 | return 1; | |
730 | if (task_is_stopped_or_traced(p)) | |
731 | return 0; | |
732 | return task_curr(p) || !signal_pending(p); | |
733 | } | |
734 | ||
5fcd835b | 735 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
736 | { |
737 | struct signal_struct *signal = p->signal; | |
738 | struct task_struct *t; | |
739 | ||
740 | /* | |
741 | * Now find a thread we can wake up to take the signal off the queue. | |
742 | * | |
743 | * If the main thread wants the signal, it gets first crack. | |
744 | * Probably the least surprising to the average bear. | |
745 | */ | |
746 | if (wants_signal(sig, p)) | |
747 | t = p; | |
5fcd835b | 748 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
749 | /* |
750 | * There is just one thread and it does not need to be woken. | |
751 | * It will dequeue unblocked signals before it runs again. | |
752 | */ | |
753 | return; | |
754 | else { | |
755 | /* | |
756 | * Otherwise try to find a suitable thread. | |
757 | */ | |
758 | t = signal->curr_target; | |
759 | while (!wants_signal(sig, t)) { | |
760 | t = next_thread(t); | |
761 | if (t == signal->curr_target) | |
762 | /* | |
763 | * No thread needs to be woken. | |
764 | * Any eligible threads will see | |
765 | * the signal in the queue soon. | |
766 | */ | |
767 | return; | |
768 | } | |
769 | signal->curr_target = t; | |
770 | } | |
771 | ||
772 | /* | |
773 | * Found a killable thread. If the signal will be fatal, | |
774 | * then start taking the whole group down immediately. | |
775 | */ | |
fae5fa44 ON |
776 | if (sig_fatal(p, sig) && |
777 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 778 | !sigismember(&t->real_blocked, sig) && |
445a91d2 RM |
779 | (sig == SIGKILL || |
780 | !tracehook_consider_fatal_signal(t, sig, SIG_DFL))) { | |
71f11dc0 ON |
781 | /* |
782 | * This signal will be fatal to the whole group. | |
783 | */ | |
784 | if (!sig_kernel_coredump(sig)) { | |
785 | /* | |
786 | * Start a group exit and wake everybody up. | |
787 | * This way we don't have other threads | |
788 | * running and doing things after a slower | |
789 | * thread has the fatal signal pending. | |
790 | */ | |
791 | signal->flags = SIGNAL_GROUP_EXIT; | |
792 | signal->group_exit_code = sig; | |
793 | signal->group_stop_count = 0; | |
794 | t = p; | |
795 | do { | |
796 | sigaddset(&t->pending.signal, SIGKILL); | |
797 | signal_wake_up(t, 1); | |
798 | } while_each_thread(p, t); | |
799 | return; | |
800 | } | |
801 | } | |
802 | ||
803 | /* | |
804 | * The signal is already in the shared-pending queue. | |
805 | * Tell the chosen thread to wake up and dequeue it. | |
806 | */ | |
807 | signal_wake_up(t, sig == SIGKILL); | |
808 | return; | |
809 | } | |
810 | ||
af7fff9c PE |
811 | static inline int legacy_queue(struct sigpending *signals, int sig) |
812 | { | |
813 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
814 | } | |
815 | ||
1da177e4 | 816 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
2ca3515a | 817 | int group) |
1da177e4 | 818 | { |
2ca3515a | 819 | struct sigpending *pending; |
6e65acba | 820 | struct sigqueue *q; |
1da177e4 | 821 | |
0a16b607 MD |
822 | trace_sched_signal_send(sig, t); |
823 | ||
6e65acba | 824 | assert_spin_locked(&t->sighand->siglock); |
7e695a5e ON |
825 | if (!prepare_signal(sig, t)) |
826 | return 0; | |
2ca3515a ON |
827 | |
828 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
829 | /* |
830 | * Short-circuit ignored signals and support queuing | |
831 | * exactly one non-rt signal, so that we can get more | |
832 | * detailed information about the cause of the signal. | |
833 | */ | |
7e695a5e | 834 | if (legacy_queue(pending, sig)) |
2acb024d | 835 | return 0; |
1da177e4 LT |
836 | /* |
837 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
838 | * or SIGKILL. | |
839 | */ | |
b67a1b9e | 840 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
841 | goto out_set; |
842 | ||
843 | /* Real-time signals must be queued if sent by sigqueue, or | |
844 | some other real-time mechanism. It is implementation | |
845 | defined whether kill() does so. We attempt to do so, on | |
846 | the principle of least surprise, but since kill is not | |
847 | allowed to fail with EAGAIN when low on memory we just | |
848 | make sure at least one signal gets delivered and don't | |
849 | pass on the info struct. */ | |
850 | ||
851 | q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN && | |
621d3121 | 852 | (is_si_special(info) || |
1da177e4 LT |
853 | info->si_code >= 0))); |
854 | if (q) { | |
2ca3515a | 855 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 856 | switch ((unsigned long) info) { |
b67a1b9e | 857 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
858 | q->info.si_signo = sig; |
859 | q->info.si_errno = 0; | |
860 | q->info.si_code = SI_USER; | |
9cd4fd10 | 861 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 862 | task_active_pid_ns(t)); |
76aac0e9 | 863 | q->info.si_uid = current_uid(); |
1da177e4 | 864 | break; |
b67a1b9e | 865 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
866 | q->info.si_signo = sig; |
867 | q->info.si_errno = 0; | |
868 | q->info.si_code = SI_KERNEL; | |
869 | q->info.si_pid = 0; | |
870 | q->info.si_uid = 0; | |
871 | break; | |
872 | default: | |
873 | copy_siginfo(&q->info, info); | |
874 | break; | |
875 | } | |
621d3121 ON |
876 | } else if (!is_si_special(info)) { |
877 | if (sig >= SIGRTMIN && info->si_code != SI_USER) | |
1da177e4 LT |
878 | /* |
879 | * Queue overflow, abort. We may abort if the signal was rt | |
880 | * and sent by user using something other than kill(). | |
881 | */ | |
882 | return -EAGAIN; | |
1da177e4 LT |
883 | } |
884 | ||
885 | out_set: | |
53c30337 | 886 | signalfd_notify(t, sig); |
2ca3515a | 887 | sigaddset(&pending->signal, sig); |
4cd4b6d4 PE |
888 | complete_signal(sig, t, group); |
889 | return 0; | |
1da177e4 LT |
890 | } |
891 | ||
45807a1d IM |
892 | int print_fatal_signals; |
893 | ||
894 | static void print_fatal_signal(struct pt_regs *regs, int signr) | |
895 | { | |
896 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 897 | current->comm, task_pid_nr(current), signr); |
45807a1d | 898 | |
ca5cd877 | 899 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 900 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
901 | { |
902 | int i; | |
903 | for (i = 0; i < 16; i++) { | |
904 | unsigned char insn; | |
905 | ||
65ea5b03 | 906 | __get_user(insn, (unsigned char *)(regs->ip + i)); |
45807a1d IM |
907 | printk("%02x ", insn); |
908 | } | |
909 | } | |
910 | #endif | |
911 | printk("\n"); | |
912 | show_regs(regs); | |
913 | } | |
914 | ||
915 | static int __init setup_print_fatal_signals(char *str) | |
916 | { | |
917 | get_option (&str, &print_fatal_signals); | |
918 | ||
919 | return 1; | |
920 | } | |
921 | ||
922 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 923 | |
4cd4b6d4 PE |
924 | int |
925 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
926 | { | |
927 | return send_signal(sig, info, p, 1); | |
928 | } | |
929 | ||
1da177e4 LT |
930 | static int |
931 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
932 | { | |
4cd4b6d4 | 933 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
934 | } |
935 | ||
936 | /* | |
937 | * Force a signal that the process can't ignore: if necessary | |
938 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
939 | * |
940 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
941 | * since we do not want to have a signal handler that was blocked | |
942 | * be invoked when user space had explicitly blocked it. | |
943 | * | |
80fe728d ON |
944 | * We don't want to have recursive SIGSEGV's etc, for example, |
945 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 946 | */ |
1da177e4 LT |
947 | int |
948 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
949 | { | |
950 | unsigned long int flags; | |
ae74c3b6 LT |
951 | int ret, blocked, ignored; |
952 | struct k_sigaction *action; | |
1da177e4 LT |
953 | |
954 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
955 | action = &t->sighand->action[sig-1]; |
956 | ignored = action->sa.sa_handler == SIG_IGN; | |
957 | blocked = sigismember(&t->blocked, sig); | |
958 | if (blocked || ignored) { | |
959 | action->sa.sa_handler = SIG_DFL; | |
960 | if (blocked) { | |
961 | sigdelset(&t->blocked, sig); | |
7bb44ade | 962 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 963 | } |
1da177e4 | 964 | } |
80fe728d ON |
965 | if (action->sa.sa_handler == SIG_DFL) |
966 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
967 | ret = specific_send_sig_info(sig, info, t); |
968 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
969 | ||
970 | return ret; | |
971 | } | |
972 | ||
973 | void | |
974 | force_sig_specific(int sig, struct task_struct *t) | |
975 | { | |
b0423a0d | 976 | force_sig_info(sig, SEND_SIG_FORCED, t); |
1da177e4 LT |
977 | } |
978 | ||
1da177e4 LT |
979 | /* |
980 | * Nuke all other threads in the group. | |
981 | */ | |
982 | void zap_other_threads(struct task_struct *p) | |
983 | { | |
984 | struct task_struct *t; | |
985 | ||
1da177e4 LT |
986 | p->signal->group_stop_count = 0; |
987 | ||
1da177e4 LT |
988 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
989 | /* | |
990 | * Don't bother with already dead threads | |
991 | */ | |
992 | if (t->exit_state) | |
993 | continue; | |
994 | ||
30e0fca6 | 995 | /* SIGKILL will be handled before any pending SIGSTOP */ |
1da177e4 | 996 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
997 | signal_wake_up(t, 1); |
998 | } | |
999 | } | |
1000 | ||
b5606c2d | 1001 | int __fatal_signal_pending(struct task_struct *tsk) |
f776d12d MW |
1002 | { |
1003 | return sigismember(&tsk->pending.signal, SIGKILL); | |
1004 | } | |
13f09b95 | 1005 | EXPORT_SYMBOL(__fatal_signal_pending); |
f776d12d | 1006 | |
f63ee72e ON |
1007 | struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) |
1008 | { | |
1009 | struct sighand_struct *sighand; | |
1010 | ||
1406f2d3 | 1011 | rcu_read_lock(); |
f63ee72e ON |
1012 | for (;;) { |
1013 | sighand = rcu_dereference(tsk->sighand); | |
1014 | if (unlikely(sighand == NULL)) | |
1015 | break; | |
1016 | ||
1017 | spin_lock_irqsave(&sighand->siglock, *flags); | |
1018 | if (likely(sighand == tsk->sighand)) | |
1019 | break; | |
1020 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
1021 | } | |
1406f2d3 | 1022 | rcu_read_unlock(); |
f63ee72e ON |
1023 | |
1024 | return sighand; | |
1025 | } | |
1026 | ||
c69e8d9c DH |
1027 | /* |
1028 | * send signal info to all the members of a group | |
1029 | * - the caller must hold the RCU read lock at least | |
1030 | */ | |
1da177e4 LT |
1031 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1032 | { | |
1033 | unsigned long flags; | |
1034 | int ret; | |
1035 | ||
1036 | ret = check_kill_permission(sig, info, p); | |
f63ee72e ON |
1037 | |
1038 | if (!ret && sig) { | |
1039 | ret = -ESRCH; | |
1040 | if (lock_task_sighand(p, &flags)) { | |
1041 | ret = __group_send_sig_info(sig, info, p); | |
1042 | unlock_task_sighand(p, &flags); | |
2d89c929 | 1043 | } |
1da177e4 LT |
1044 | } |
1045 | ||
1046 | return ret; | |
1047 | } | |
1048 | ||
1049 | /* | |
146a505d | 1050 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1051 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1052 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1053 | */ |
c4b92fc1 | 1054 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1055 | { |
1056 | struct task_struct *p = NULL; | |
1057 | int retval, success; | |
1058 | ||
1da177e4 LT |
1059 | success = 0; |
1060 | retval = -ESRCH; | |
c4b92fc1 | 1061 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1062 | int err = group_send_sig_info(sig, info, p); |
1063 | success |= !err; | |
1064 | retval = err; | |
c4b92fc1 | 1065 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1066 | return success ? 0 : retval; |
1067 | } | |
1068 | ||
c4b92fc1 | 1069 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1070 | { |
d36174bc | 1071 | int error = -ESRCH; |
1da177e4 LT |
1072 | struct task_struct *p; |
1073 | ||
e56d0903 | 1074 | rcu_read_lock(); |
d36174bc | 1075 | retry: |
c4b92fc1 | 1076 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1077 | if (p) { |
1da177e4 | 1078 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1079 | if (unlikely(error == -ESRCH)) |
1080 | /* | |
1081 | * The task was unhashed in between, try again. | |
1082 | * If it is dead, pid_task() will return NULL, | |
1083 | * if we race with de_thread() it will find the | |
1084 | * new leader. | |
1085 | */ | |
1086 | goto retry; | |
1087 | } | |
e56d0903 | 1088 | rcu_read_unlock(); |
6ca25b55 | 1089 | |
1da177e4 LT |
1090 | return error; |
1091 | } | |
1092 | ||
c3de4b38 MW |
1093 | int |
1094 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
c4b92fc1 EB |
1095 | { |
1096 | int error; | |
1097 | rcu_read_lock(); | |
b488893a | 1098 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1099 | rcu_read_unlock(); |
1100 | return error; | |
1101 | } | |
1102 | ||
2425c08b EB |
1103 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1104 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1105 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1106 | { |
1107 | int ret = -EINVAL; | |
1108 | struct task_struct *p; | |
c69e8d9c | 1109 | const struct cred *pcred; |
46113830 HW |
1110 | |
1111 | if (!valid_signal(sig)) | |
1112 | return ret; | |
1113 | ||
1114 | read_lock(&tasklist_lock); | |
2425c08b | 1115 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1116 | if (!p) { |
1117 | ret = -ESRCH; | |
1118 | goto out_unlock; | |
1119 | } | |
c69e8d9c DH |
1120 | pcred = __task_cred(p); |
1121 | if ((info == SEND_SIG_NOINFO || | |
1122 | (!is_si_special(info) && SI_FROMUSER(info))) && | |
1123 | euid != pcred->suid && euid != pcred->uid && | |
1124 | uid != pcred->suid && uid != pcred->uid) { | |
46113830 HW |
1125 | ret = -EPERM; |
1126 | goto out_unlock; | |
1127 | } | |
8f95dc58 DQ |
1128 | ret = security_task_kill(p, info, sig, secid); |
1129 | if (ret) | |
1130 | goto out_unlock; | |
46113830 HW |
1131 | if (sig && p->sighand) { |
1132 | unsigned long flags; | |
1133 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1134 | ret = __group_send_sig_info(sig, info, p); | |
1135 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1136 | } | |
1137 | out_unlock: | |
1138 | read_unlock(&tasklist_lock); | |
1139 | return ret; | |
1140 | } | |
2425c08b | 1141 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1142 | |
1143 | /* | |
1144 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1145 | * | |
1146 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1147 | * is probably wrong. Should make it like BSD or SYSV. | |
1148 | */ | |
1149 | ||
bc64efd2 | 1150 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1151 | { |
8d42db18 | 1152 | int ret; |
d5df763b PE |
1153 | |
1154 | if (pid > 0) { | |
1155 | rcu_read_lock(); | |
1156 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1157 | rcu_read_unlock(); | |
1158 | return ret; | |
1159 | } | |
1160 | ||
1161 | read_lock(&tasklist_lock); | |
1162 | if (pid != -1) { | |
1163 | ret = __kill_pgrp_info(sig, info, | |
1164 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1165 | } else { | |
1da177e4 LT |
1166 | int retval = 0, count = 0; |
1167 | struct task_struct * p; | |
1168 | ||
1da177e4 | 1169 | for_each_process(p) { |
d25141a8 SB |
1170 | if (task_pid_vnr(p) > 1 && |
1171 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1172 | int err = group_send_sig_info(sig, info, p); |
1173 | ++count; | |
1174 | if (err != -EPERM) | |
1175 | retval = err; | |
1176 | } | |
1177 | } | |
8d42db18 | 1178 | ret = count ? retval : -ESRCH; |
1da177e4 | 1179 | } |
d5df763b PE |
1180 | read_unlock(&tasklist_lock); |
1181 | ||
8d42db18 | 1182 | return ret; |
1da177e4 LT |
1183 | } |
1184 | ||
1185 | /* | |
1186 | * These are for backward compatibility with the rest of the kernel source. | |
1187 | */ | |
1188 | ||
1189 | /* | |
08d2c30c | 1190 | * The caller must ensure the task can't exit. |
1da177e4 LT |
1191 | */ |
1192 | int | |
1193 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1194 | { | |
1195 | int ret; | |
1196 | unsigned long flags; | |
1197 | ||
1198 | /* | |
1199 | * Make sure legacy kernel users don't send in bad values | |
1200 | * (normal paths check this in check_kill_permission). | |
1201 | */ | |
7ed20e1a | 1202 | if (!valid_signal(sig)) |
1da177e4 LT |
1203 | return -EINVAL; |
1204 | ||
1da177e4 LT |
1205 | spin_lock_irqsave(&p->sighand->siglock, flags); |
1206 | ret = specific_send_sig_info(sig, info, p); | |
1207 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1da177e4 LT |
1208 | return ret; |
1209 | } | |
1210 | ||
b67a1b9e ON |
1211 | #define __si_special(priv) \ |
1212 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1213 | ||
1da177e4 LT |
1214 | int |
1215 | send_sig(int sig, struct task_struct *p, int priv) | |
1216 | { | |
b67a1b9e | 1217 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1218 | } |
1219 | ||
1da177e4 LT |
1220 | void |
1221 | force_sig(int sig, struct task_struct *p) | |
1222 | { | |
b67a1b9e | 1223 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1224 | } |
1225 | ||
1226 | /* | |
1227 | * When things go south during signal handling, we | |
1228 | * will force a SIGSEGV. And if the signal that caused | |
1229 | * the problem was already a SIGSEGV, we'll want to | |
1230 | * make sure we don't even try to deliver the signal.. | |
1231 | */ | |
1232 | int | |
1233 | force_sigsegv(int sig, struct task_struct *p) | |
1234 | { | |
1235 | if (sig == SIGSEGV) { | |
1236 | unsigned long flags; | |
1237 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1238 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1239 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1240 | } | |
1241 | force_sig(SIGSEGV, p); | |
1242 | return 0; | |
1243 | } | |
1244 | ||
c4b92fc1 EB |
1245 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1246 | { | |
146a505d PE |
1247 | int ret; |
1248 | ||
1249 | read_lock(&tasklist_lock); | |
1250 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1251 | read_unlock(&tasklist_lock); | |
1252 | ||
1253 | return ret; | |
c4b92fc1 EB |
1254 | } |
1255 | EXPORT_SYMBOL(kill_pgrp); | |
1256 | ||
1257 | int kill_pid(struct pid *pid, int sig, int priv) | |
1258 | { | |
1259 | return kill_pid_info(sig, __si_special(priv), pid); | |
1260 | } | |
1261 | EXPORT_SYMBOL(kill_pid); | |
1262 | ||
1da177e4 LT |
1263 | /* |
1264 | * These functions support sending signals using preallocated sigqueue | |
1265 | * structures. This is needed "because realtime applications cannot | |
1266 | * afford to lose notifications of asynchronous events, like timer | |
1267 | * expirations or I/O completions". In the case of Posix Timers | |
1268 | * we allocate the sigqueue structure from the timer_create. If this | |
1269 | * allocation fails we are able to report the failure to the application | |
1270 | * with an EAGAIN error. | |
1271 | */ | |
1272 | ||
1273 | struct sigqueue *sigqueue_alloc(void) | |
1274 | { | |
1275 | struct sigqueue *q; | |
1276 | ||
1277 | if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) | |
1278 | q->flags |= SIGQUEUE_PREALLOC; | |
1279 | return(q); | |
1280 | } | |
1281 | ||
1282 | void sigqueue_free(struct sigqueue *q) | |
1283 | { | |
1284 | unsigned long flags; | |
60187d27 ON |
1285 | spinlock_t *lock = ¤t->sighand->siglock; |
1286 | ||
1da177e4 LT |
1287 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1288 | /* | |
c8e85b4f ON |
1289 | * We must hold ->siglock while testing q->list |
1290 | * to serialize with collect_signal() or with | |
da7978b0 | 1291 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1292 | */ |
60187d27 | 1293 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1294 | q->flags &= ~SIGQUEUE_PREALLOC; |
1295 | /* | |
1296 | * If it is queued it will be freed when dequeued, | |
1297 | * like the "regular" sigqueue. | |
1298 | */ | |
60187d27 | 1299 | if (!list_empty(&q->list)) |
c8e85b4f | 1300 | q = NULL; |
60187d27 ON |
1301 | spin_unlock_irqrestore(lock, flags); |
1302 | ||
c8e85b4f ON |
1303 | if (q) |
1304 | __sigqueue_free(q); | |
1da177e4 LT |
1305 | } |
1306 | ||
ac5c2153 | 1307 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1308 | { |
e62e6650 | 1309 | int sig = q->info.si_signo; |
2ca3515a | 1310 | struct sigpending *pending; |
e62e6650 ON |
1311 | unsigned long flags; |
1312 | int ret; | |
2ca3515a | 1313 | |
4cd4b6d4 | 1314 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1315 | |
1316 | ret = -1; | |
1317 | if (!likely(lock_task_sighand(t, &flags))) | |
1318 | goto ret; | |
1319 | ||
7e695a5e ON |
1320 | ret = 1; /* the signal is ignored */ |
1321 | if (!prepare_signal(sig, t)) | |
e62e6650 ON |
1322 | goto out; |
1323 | ||
1324 | ret = 0; | |
9e3bd6c3 PE |
1325 | if (unlikely(!list_empty(&q->list))) { |
1326 | /* | |
1327 | * If an SI_TIMER entry is already queue just increment | |
1328 | * the overrun count. | |
1329 | */ | |
9e3bd6c3 PE |
1330 | BUG_ON(q->info.si_code != SI_TIMER); |
1331 | q->info.si_overrun++; | |
e62e6650 | 1332 | goto out; |
9e3bd6c3 | 1333 | } |
ba661292 | 1334 | q->info.si_overrun = 0; |
9e3bd6c3 | 1335 | |
9e3bd6c3 | 1336 | signalfd_notify(t, sig); |
2ca3515a | 1337 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1338 | list_add_tail(&q->list, &pending->list); |
1339 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1340 | complete_signal(sig, t, group); |
e62e6650 ON |
1341 | out: |
1342 | unlock_task_sighand(t, &flags); | |
1343 | ret: | |
1344 | return ret; | |
9e3bd6c3 PE |
1345 | } |
1346 | ||
1da177e4 LT |
1347 | /* |
1348 | * Wake up any threads in the parent blocked in wait* syscalls. | |
1349 | */ | |
1350 | static inline void __wake_up_parent(struct task_struct *p, | |
1351 | struct task_struct *parent) | |
1352 | { | |
1353 | wake_up_interruptible_sync(&parent->signal->wait_chldexit); | |
1354 | } | |
1355 | ||
1356 | /* | |
1357 | * Let a parent know about the death of a child. | |
1358 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 RM |
1359 | * |
1360 | * Returns -1 if our parent ignored us and so we've switched to | |
1361 | * self-reaping, or else @sig. | |
1da177e4 | 1362 | */ |
2b2a1ff6 | 1363 | int do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1364 | { |
1365 | struct siginfo info; | |
1366 | unsigned long flags; | |
1367 | struct sighand_struct *psig; | |
f06febc9 | 1368 | struct task_cputime cputime; |
1b04624f | 1369 | int ret = sig; |
1da177e4 LT |
1370 | |
1371 | BUG_ON(sig == -1); | |
1372 | ||
1373 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1374 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 LT |
1375 | |
1376 | BUG_ON(!tsk->ptrace && | |
1377 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); | |
1378 | ||
1379 | info.si_signo = sig; | |
1380 | info.si_errno = 0; | |
b488893a PE |
1381 | /* |
1382 | * we are under tasklist_lock here so our parent is tied to | |
1383 | * us and cannot exit and release its namespace. | |
1384 | * | |
1385 | * the only it can is to switch its nsproxy with sys_unshare, | |
1386 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1387 | * see relevant namespace | |
1388 | * | |
1389 | * write_lock() currently calls preempt_disable() which is the | |
1390 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1391 | * correct to rely on this | |
1392 | */ | |
1393 | rcu_read_lock(); | |
1394 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
c69e8d9c | 1395 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1396 | rcu_read_unlock(); |
1397 | ||
f06febc9 FM |
1398 | thread_group_cputime(tsk, &cputime); |
1399 | info.si_utime = cputime_to_jiffies(cputime.utime); | |
1400 | info.si_stime = cputime_to_jiffies(cputime.stime); | |
1da177e4 LT |
1401 | |
1402 | info.si_status = tsk->exit_code & 0x7f; | |
1403 | if (tsk->exit_code & 0x80) | |
1404 | info.si_code = CLD_DUMPED; | |
1405 | else if (tsk->exit_code & 0x7f) | |
1406 | info.si_code = CLD_KILLED; | |
1407 | else { | |
1408 | info.si_code = CLD_EXITED; | |
1409 | info.si_status = tsk->exit_code >> 8; | |
1410 | } | |
1411 | ||
1412 | psig = tsk->parent->sighand; | |
1413 | spin_lock_irqsave(&psig->siglock, flags); | |
7ed0175a | 1414 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1415 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1416 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1417 | /* | |
1418 | * We are exiting and our parent doesn't care. POSIX.1 | |
1419 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1420 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1421 | * automatically and not left for our parent's wait4 call. | |
1422 | * Rather than having the parent do it as a magic kind of | |
1423 | * signal handler, we just set this to tell do_exit that we | |
1424 | * can be cleaned up without becoming a zombie. Note that | |
1425 | * we still call __wake_up_parent in this case, because a | |
1426 | * blocked sys_wait4 might now return -ECHILD. | |
1427 | * | |
1428 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1429 | * is implementation-defined: we do (if you don't want | |
1430 | * it, just use SIG_IGN instead). | |
1431 | */ | |
1b04624f | 1432 | ret = tsk->exit_signal = -1; |
1da177e4 | 1433 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
2b2a1ff6 | 1434 | sig = -1; |
1da177e4 | 1435 | } |
7ed20e1a | 1436 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1437 | __group_send_sig_info(sig, &info, tsk->parent); |
1438 | __wake_up_parent(tsk, tsk->parent); | |
1439 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1440 | |
1b04624f | 1441 | return ret; |
1da177e4 LT |
1442 | } |
1443 | ||
a1d5e21e | 1444 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why) |
1da177e4 LT |
1445 | { |
1446 | struct siginfo info; | |
1447 | unsigned long flags; | |
bc505a47 | 1448 | struct task_struct *parent; |
1da177e4 LT |
1449 | struct sighand_struct *sighand; |
1450 | ||
a1d5e21e | 1451 | if (tsk->ptrace & PT_PTRACED) |
bc505a47 ON |
1452 | parent = tsk->parent; |
1453 | else { | |
1454 | tsk = tsk->group_leader; | |
1455 | parent = tsk->real_parent; | |
1456 | } | |
1457 | ||
1da177e4 LT |
1458 | info.si_signo = SIGCHLD; |
1459 | info.si_errno = 0; | |
b488893a PE |
1460 | /* |
1461 | * see comment in do_notify_parent() abot the following 3 lines | |
1462 | */ | |
1463 | rcu_read_lock(); | |
1464 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
c69e8d9c | 1465 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1466 | rcu_read_unlock(); |
1467 | ||
d8878ba3 MK |
1468 | info.si_utime = cputime_to_clock_t(tsk->utime); |
1469 | info.si_stime = cputime_to_clock_t(tsk->stime); | |
1da177e4 LT |
1470 | |
1471 | info.si_code = why; | |
1472 | switch (why) { | |
1473 | case CLD_CONTINUED: | |
1474 | info.si_status = SIGCONT; | |
1475 | break; | |
1476 | case CLD_STOPPED: | |
1477 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1478 | break; | |
1479 | case CLD_TRAPPED: | |
1480 | info.si_status = tsk->exit_code & 0x7f; | |
1481 | break; | |
1482 | default: | |
1483 | BUG(); | |
1484 | } | |
1485 | ||
1486 | sighand = parent->sighand; | |
1487 | spin_lock_irqsave(&sighand->siglock, flags); | |
1488 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1489 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1490 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1491 | /* | |
1492 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1493 | */ | |
1494 | __wake_up_parent(tsk, parent); | |
1495 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1496 | } | |
1497 | ||
d5f70c00 ON |
1498 | static inline int may_ptrace_stop(void) |
1499 | { | |
1500 | if (!likely(current->ptrace & PT_PTRACED)) | |
1501 | return 0; | |
d5f70c00 ON |
1502 | /* |
1503 | * Are we in the middle of do_coredump? | |
1504 | * If so and our tracer is also part of the coredump stopping | |
1505 | * is a deadlock situation, and pointless because our tracer | |
1506 | * is dead so don't allow us to stop. | |
1507 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1508 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 ON |
1509 | * is safe to enter schedule(). |
1510 | */ | |
999d9fc1 | 1511 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1512 | unlikely(current->mm == current->parent->mm)) |
1513 | return 0; | |
1514 | ||
1515 | return 1; | |
1516 | } | |
1517 | ||
1a669c2f RM |
1518 | /* |
1519 | * Return nonzero if there is a SIGKILL that should be waking us up. | |
1520 | * Called with the siglock held. | |
1521 | */ | |
1522 | static int sigkill_pending(struct task_struct *tsk) | |
1523 | { | |
3d749b9e ON |
1524 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1525 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1526 | } |
1527 | ||
1da177e4 LT |
1528 | /* |
1529 | * This must be called with current->sighand->siglock held. | |
1530 | * | |
1531 | * This should be the path for all ptrace stops. | |
1532 | * We always set current->last_siginfo while stopped here. | |
1533 | * That makes it a way to test a stopped process for | |
1534 | * being ptrace-stopped vs being job-control-stopped. | |
1535 | * | |
20686a30 ON |
1536 | * If we actually decide not to stop at all because the tracer |
1537 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1538 | */ |
20686a30 | 1539 | static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) |
1da177e4 | 1540 | { |
1a669c2f RM |
1541 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1542 | /* | |
1543 | * The arch code has something special to do before a | |
1544 | * ptrace stop. This is allowed to block, e.g. for faults | |
1545 | * on user stack pages. We can't keep the siglock while | |
1546 | * calling arch_ptrace_stop, so we must release it now. | |
1547 | * To preserve proper semantics, we must do this before | |
1548 | * any signal bookkeeping like checking group_stop_count. | |
1549 | * Meanwhile, a SIGKILL could come in before we retake the | |
1550 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1551 | * So after regaining the lock, we must check for SIGKILL. | |
1552 | */ | |
1553 | spin_unlock_irq(¤t->sighand->siglock); | |
1554 | arch_ptrace_stop(exit_code, info); | |
1555 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1556 | if (sigkill_pending(current)) |
1557 | return; | |
1a669c2f RM |
1558 | } |
1559 | ||
1da177e4 LT |
1560 | /* |
1561 | * If there is a group stop in progress, | |
1562 | * we must participate in the bookkeeping. | |
1563 | */ | |
1564 | if (current->signal->group_stop_count > 0) | |
1565 | --current->signal->group_stop_count; | |
1566 | ||
1567 | current->last_siginfo = info; | |
1568 | current->exit_code = exit_code; | |
1569 | ||
1570 | /* Let the debugger run. */ | |
d9ae90ac | 1571 | __set_current_state(TASK_TRACED); |
1da177e4 LT |
1572 | spin_unlock_irq(¤t->sighand->siglock); |
1573 | read_lock(&tasklist_lock); | |
3d749b9e | 1574 | if (may_ptrace_stop()) { |
a1d5e21e | 1575 | do_notify_parent_cldstop(current, CLD_TRAPPED); |
1da177e4 LT |
1576 | read_unlock(&tasklist_lock); |
1577 | schedule(); | |
1578 | } else { | |
1579 | /* | |
1580 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1581 | * Don't drop the lock yet, another tracer may come. |
1da177e4 | 1582 | */ |
6405f7f4 | 1583 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1584 | if (clear_code) |
1585 | current->exit_code = 0; | |
6405f7f4 | 1586 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1587 | } |
1588 | ||
13b1c3d4 RM |
1589 | /* |
1590 | * While in TASK_TRACED, we were considered "frozen enough". | |
1591 | * Now that we woke up, it's crucial if we're supposed to be | |
1592 | * frozen that we freeze now before running anything substantial. | |
1593 | */ | |
1594 | try_to_freeze(); | |
1595 | ||
1da177e4 LT |
1596 | /* |
1597 | * We are back. Now reacquire the siglock before touching | |
1598 | * last_siginfo, so that we are sure to have synchronized with | |
1599 | * any signal-sending on another CPU that wants to examine it. | |
1600 | */ | |
1601 | spin_lock_irq(¤t->sighand->siglock); | |
1602 | current->last_siginfo = NULL; | |
1603 | ||
1604 | /* | |
1605 | * Queued signals ignored us while we were stopped for tracing. | |
1606 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1607 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1608 | */ |
b74d0deb | 1609 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1610 | } |
1611 | ||
1612 | void ptrace_notify(int exit_code) | |
1613 | { | |
1614 | siginfo_t info; | |
1615 | ||
1616 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1617 | ||
1618 | memset(&info, 0, sizeof info); | |
1619 | info.si_signo = SIGTRAP; | |
1620 | info.si_code = exit_code; | |
b488893a | 1621 | info.si_pid = task_pid_vnr(current); |
76aac0e9 | 1622 | info.si_uid = current_uid(); |
1da177e4 LT |
1623 | |
1624 | /* Let the debugger run. */ | |
1625 | spin_lock_irq(¤t->sighand->siglock); | |
20686a30 | 1626 | ptrace_stop(exit_code, 1, &info); |
1da177e4 LT |
1627 | spin_unlock_irq(¤t->sighand->siglock); |
1628 | } | |
1629 | ||
1da177e4 LT |
1630 | static void |
1631 | finish_stop(int stop_count) | |
1632 | { | |
1633 | /* | |
1634 | * If there are no other threads in the group, or if there is | |
1635 | * a group stop in progress and we are the last to stop, | |
1636 | * report to the parent. When ptraced, every thread reports itself. | |
1637 | */ | |
fa00b80b | 1638 | if (tracehook_notify_jctl(stop_count == 0, CLD_STOPPED)) { |
a1d5e21e ON |
1639 | read_lock(&tasklist_lock); |
1640 | do_notify_parent_cldstop(current, CLD_STOPPED); | |
1641 | read_unlock(&tasklist_lock); | |
1642 | } | |
bc505a47 | 1643 | |
3df494a3 RW |
1644 | do { |
1645 | schedule(); | |
1646 | } while (try_to_freeze()); | |
1da177e4 LT |
1647 | /* |
1648 | * Now we don't run again until continued. | |
1649 | */ | |
1650 | current->exit_code = 0; | |
1651 | } | |
1652 | ||
1653 | /* | |
1654 | * This performs the stopping for SIGSTOP and other stop signals. | |
1655 | * We have to stop all threads in the thread group. | |
1656 | * Returns nonzero if we've actually stopped and released the siglock. | |
1657 | * Returns zero if we didn't stop and still hold the siglock. | |
1658 | */ | |
a122b341 | 1659 | static int do_signal_stop(int signr) |
1da177e4 LT |
1660 | { |
1661 | struct signal_struct *sig = current->signal; | |
dac27f4a | 1662 | int stop_count; |
1da177e4 | 1663 | |
1da177e4 LT |
1664 | if (sig->group_stop_count > 0) { |
1665 | /* | |
1666 | * There is a group stop in progress. We don't need to | |
1667 | * start another one. | |
1668 | */ | |
1da177e4 | 1669 | stop_count = --sig->group_stop_count; |
dac27f4a | 1670 | } else { |
f558b7e4 ON |
1671 | struct task_struct *t; |
1672 | ||
2b201a9e | 1673 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) || |
573cf9ad | 1674 | unlikely(signal_group_exit(sig))) |
f558b7e4 | 1675 | return 0; |
1da177e4 LT |
1676 | /* |
1677 | * There is no group stop already in progress. | |
a122b341 | 1678 | * We must initiate one now. |
1da177e4 | 1679 | */ |
a122b341 | 1680 | sig->group_exit_code = signr; |
1da177e4 | 1681 | |
a122b341 ON |
1682 | stop_count = 0; |
1683 | for (t = next_thread(current); t != current; t = next_thread(t)) | |
1da177e4 | 1684 | /* |
a122b341 ON |
1685 | * Setting state to TASK_STOPPED for a group |
1686 | * stop is always done with the siglock held, | |
1687 | * so this check has no races. | |
1da177e4 | 1688 | */ |
d12619b5 | 1689 | if (!(t->flags & PF_EXITING) && |
e1abb39c | 1690 | !task_is_stopped_or_traced(t)) { |
a122b341 ON |
1691 | stop_count++; |
1692 | signal_wake_up(t, 0); | |
1693 | } | |
1694 | sig->group_stop_count = stop_count; | |
1da177e4 LT |
1695 | } |
1696 | ||
dac27f4a ON |
1697 | if (stop_count == 0) |
1698 | sig->flags = SIGNAL_STOP_STOPPED; | |
1699 | current->exit_code = sig->group_exit_code; | |
1700 | __set_current_state(TASK_STOPPED); | |
1701 | ||
1702 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
1703 | finish_stop(stop_count); |
1704 | return 1; | |
1705 | } | |
1706 | ||
18c98b65 RM |
1707 | static int ptrace_signal(int signr, siginfo_t *info, |
1708 | struct pt_regs *regs, void *cookie) | |
1709 | { | |
1710 | if (!(current->ptrace & PT_PTRACED)) | |
1711 | return signr; | |
1712 | ||
1713 | ptrace_signal_deliver(regs, cookie); | |
1714 | ||
1715 | /* Let the debugger run. */ | |
1716 | ptrace_stop(signr, 0, info); | |
1717 | ||
1718 | /* We're back. Did the debugger cancel the sig? */ | |
1719 | signr = current->exit_code; | |
1720 | if (signr == 0) | |
1721 | return signr; | |
1722 | ||
1723 | current->exit_code = 0; | |
1724 | ||
1725 | /* Update the siginfo structure if the signal has | |
1726 | changed. If the debugger wanted something | |
1727 | specific in the siginfo structure then it should | |
1728 | have updated *info via PTRACE_SETSIGINFO. */ | |
1729 | if (signr != info->si_signo) { | |
1730 | info->si_signo = signr; | |
1731 | info->si_errno = 0; | |
1732 | info->si_code = SI_USER; | |
1733 | info->si_pid = task_pid_vnr(current->parent); | |
c69e8d9c | 1734 | info->si_uid = task_uid(current->parent); |
18c98b65 RM |
1735 | } |
1736 | ||
1737 | /* If the (new) signal is now blocked, requeue it. */ | |
1738 | if (sigismember(¤t->blocked, signr)) { | |
1739 | specific_send_sig_info(signr, info, current); | |
1740 | signr = 0; | |
1741 | } | |
1742 | ||
1743 | return signr; | |
1744 | } | |
1745 | ||
1da177e4 LT |
1746 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
1747 | struct pt_regs *regs, void *cookie) | |
1748 | { | |
f6b76d4f ON |
1749 | struct sighand_struct *sighand = current->sighand; |
1750 | struct signal_struct *signal = current->signal; | |
1751 | int signr; | |
1da177e4 | 1752 | |
13b1c3d4 RM |
1753 | relock: |
1754 | /* | |
1755 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
1756 | * While in TASK_STOPPED, we were considered "frozen enough". | |
1757 | * Now that we woke up, it's crucial if we're supposed to be | |
1758 | * frozen that we freeze now before running anything substantial. | |
1759 | */ | |
fc558a74 RW |
1760 | try_to_freeze(); |
1761 | ||
f6b76d4f | 1762 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
1763 | /* |
1764 | * Every stopped thread goes here after wakeup. Check to see if | |
1765 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
1766 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
1767 | */ | |
f6b76d4f ON |
1768 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
1769 | int why = (signal->flags & SIGNAL_STOP_CONTINUED) | |
e4420551 | 1770 | ? CLD_CONTINUED : CLD_STOPPED; |
f6b76d4f ON |
1771 | signal->flags &= ~SIGNAL_CLD_MASK; |
1772 | spin_unlock_irq(&sighand->siglock); | |
e4420551 | 1773 | |
fa00b80b RM |
1774 | if (unlikely(!tracehook_notify_jctl(1, why))) |
1775 | goto relock; | |
1776 | ||
e4420551 ON |
1777 | read_lock(&tasklist_lock); |
1778 | do_notify_parent_cldstop(current->group_leader, why); | |
1779 | read_unlock(&tasklist_lock); | |
1780 | goto relock; | |
1781 | } | |
1782 | ||
1da177e4 LT |
1783 | for (;;) { |
1784 | struct k_sigaction *ka; | |
1785 | ||
f6b76d4f | 1786 | if (unlikely(signal->group_stop_count > 0) && |
f558b7e4 | 1787 | do_signal_stop(0)) |
1da177e4 LT |
1788 | goto relock; |
1789 | ||
7bcf6a2c RM |
1790 | /* |
1791 | * Tracing can induce an artifical signal and choose sigaction. | |
1792 | * The return value in @signr determines the default action, | |
1793 | * but @info->si_signo is the signal number we will report. | |
1794 | */ | |
1795 | signr = tracehook_get_signal(current, regs, info, return_ka); | |
1796 | if (unlikely(signr < 0)) | |
1797 | goto relock; | |
1798 | if (unlikely(signr != 0)) | |
1799 | ka = return_ka; | |
1800 | else { | |
1801 | signr = dequeue_signal(current, ¤t->blocked, | |
1802 | info); | |
1da177e4 | 1803 | |
18c98b65 | 1804 | if (!signr) |
7bcf6a2c RM |
1805 | break; /* will return 0 */ |
1806 | ||
1807 | if (signr != SIGKILL) { | |
1808 | signr = ptrace_signal(signr, info, | |
1809 | regs, cookie); | |
1810 | if (!signr) | |
1811 | continue; | |
1812 | } | |
1813 | ||
1814 | ka = &sighand->action[signr-1]; | |
1da177e4 LT |
1815 | } |
1816 | ||
1da177e4 LT |
1817 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
1818 | continue; | |
1819 | if (ka->sa.sa_handler != SIG_DFL) { | |
1820 | /* Run the handler. */ | |
1821 | *return_ka = *ka; | |
1822 | ||
1823 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1824 | ka->sa.sa_handler = SIG_DFL; | |
1825 | ||
1826 | break; /* will return non-zero "signr" value */ | |
1827 | } | |
1828 | ||
1829 | /* | |
1830 | * Now we are doing the default action for this signal. | |
1831 | */ | |
1832 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1833 | continue; | |
1834 | ||
84d73786 | 1835 | /* |
0fbc26a6 | 1836 | * Global init gets no signals it doesn't want. |
84d73786 | 1837 | */ |
fae5fa44 ON |
1838 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
1839 | !signal_group_exit(signal)) | |
1da177e4 LT |
1840 | continue; |
1841 | ||
1842 | if (sig_kernel_stop(signr)) { | |
1843 | /* | |
1844 | * The default action is to stop all threads in | |
1845 | * the thread group. The job control signals | |
1846 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1847 | * always works. Note that siglock needs to be | |
1848 | * dropped during the call to is_orphaned_pgrp() | |
1849 | * because of lock ordering with tasklist_lock. | |
1850 | * This allows an intervening SIGCONT to be posted. | |
1851 | * We need to check for that and bail out if necessary. | |
1852 | */ | |
1853 | if (signr != SIGSTOP) { | |
f6b76d4f | 1854 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1855 | |
1856 | /* signals can be posted during this window */ | |
1857 | ||
3e7cd6c4 | 1858 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
1859 | goto relock; |
1860 | ||
f6b76d4f | 1861 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
1862 | } |
1863 | ||
7bcf6a2c | 1864 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
1865 | /* It released the siglock. */ |
1866 | goto relock; | |
1867 | } | |
1868 | ||
1869 | /* | |
1870 | * We didn't actually stop, due to a race | |
1871 | * with SIGCONT or something like that. | |
1872 | */ | |
1873 | continue; | |
1874 | } | |
1875 | ||
f6b76d4f | 1876 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1877 | |
1878 | /* | |
1879 | * Anything else is fatal, maybe with a core dump. | |
1880 | */ | |
1881 | current->flags |= PF_SIGNALED; | |
2dce81bf | 1882 | |
1da177e4 | 1883 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 1884 | if (print_fatal_signals) |
7bcf6a2c | 1885 | print_fatal_signal(regs, info->si_signo); |
1da177e4 LT |
1886 | /* |
1887 | * If it was able to dump core, this kills all | |
1888 | * other threads in the group and synchronizes with | |
1889 | * their demise. If we lost the race with another | |
1890 | * thread getting here, it set group_exit_code | |
1891 | * first and our do_group_exit call below will use | |
1892 | * that value and ignore the one we pass it. | |
1893 | */ | |
7bcf6a2c | 1894 | do_coredump(info->si_signo, info->si_signo, regs); |
1da177e4 LT |
1895 | } |
1896 | ||
1897 | /* | |
1898 | * Death signals, no core dump. | |
1899 | */ | |
7bcf6a2c | 1900 | do_group_exit(info->si_signo); |
1da177e4 LT |
1901 | /* NOTREACHED */ |
1902 | } | |
f6b76d4f | 1903 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1904 | return signr; |
1905 | } | |
1906 | ||
d12619b5 ON |
1907 | void exit_signals(struct task_struct *tsk) |
1908 | { | |
1909 | int group_stop = 0; | |
5dee1707 | 1910 | struct task_struct *t; |
d12619b5 | 1911 | |
5dee1707 ON |
1912 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
1913 | tsk->flags |= PF_EXITING; | |
1914 | return; | |
d12619b5 ON |
1915 | } |
1916 | ||
5dee1707 | 1917 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
1918 | /* |
1919 | * From now this task is not visible for group-wide signals, | |
1920 | * see wants_signal(), do_signal_stop(). | |
1921 | */ | |
1922 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
1923 | if (!signal_pending(tsk)) |
1924 | goto out; | |
1925 | ||
1926 | /* It could be that __group_complete_signal() choose us to | |
1927 | * notify about group-wide signal. Another thread should be | |
1928 | * woken now to take the signal since we will not. | |
1929 | */ | |
1930 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
1931 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
1932 | recalc_sigpending_and_wake(t); | |
1933 | ||
1934 | if (unlikely(tsk->signal->group_stop_count) && | |
1935 | !--tsk->signal->group_stop_count) { | |
1936 | tsk->signal->flags = SIGNAL_STOP_STOPPED; | |
1937 | group_stop = 1; | |
1938 | } | |
1939 | out: | |
d12619b5 ON |
1940 | spin_unlock_irq(&tsk->sighand->siglock); |
1941 | ||
fa00b80b | 1942 | if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) { |
d12619b5 ON |
1943 | read_lock(&tasklist_lock); |
1944 | do_notify_parent_cldstop(tsk, CLD_STOPPED); | |
1945 | read_unlock(&tasklist_lock); | |
1946 | } | |
1947 | } | |
1948 | ||
1da177e4 LT |
1949 | EXPORT_SYMBOL(recalc_sigpending); |
1950 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
1951 | EXPORT_SYMBOL(flush_signals); | |
1952 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
1953 | EXPORT_SYMBOL(send_sig); |
1954 | EXPORT_SYMBOL(send_sig_info); | |
1955 | EXPORT_SYMBOL(sigprocmask); | |
1956 | EXPORT_SYMBOL(block_all_signals); | |
1957 | EXPORT_SYMBOL(unblock_all_signals); | |
1958 | ||
1959 | ||
1960 | /* | |
1961 | * System call entry points. | |
1962 | */ | |
1963 | ||
754fe8d2 | 1964 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
1965 | { |
1966 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
1967 | return restart->fn(restart); | |
1968 | } | |
1969 | ||
1970 | long do_no_restart_syscall(struct restart_block *param) | |
1971 | { | |
1972 | return -EINTR; | |
1973 | } | |
1974 | ||
1975 | /* | |
1976 | * We don't need to get the kernel lock - this is all local to this | |
1977 | * particular thread.. (and that's good, because this is _heavily_ | |
1978 | * used by various programs) | |
1979 | */ | |
1980 | ||
1981 | /* | |
1982 | * This is also useful for kernel threads that want to temporarily | |
1983 | * (or permanently) block certain signals. | |
1984 | * | |
1985 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
1986 | * interface happily blocks "unblockable" signals like SIGKILL | |
1987 | * and friends. | |
1988 | */ | |
1989 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
1990 | { | |
1991 | int error; | |
1da177e4 LT |
1992 | |
1993 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
1994 | if (oldset) |
1995 | *oldset = current->blocked; | |
1996 | ||
1da177e4 LT |
1997 | error = 0; |
1998 | switch (how) { | |
1999 | case SIG_BLOCK: | |
2000 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2001 | break; | |
2002 | case SIG_UNBLOCK: | |
2003 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2004 | break; | |
2005 | case SIG_SETMASK: | |
2006 | current->blocked = *set; | |
2007 | break; | |
2008 | default: | |
2009 | error = -EINVAL; | |
2010 | } | |
2011 | recalc_sigpending(); | |
2012 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 2013 | |
1da177e4 LT |
2014 | return error; |
2015 | } | |
2016 | ||
17da2bd9 HC |
2017 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set, |
2018 | sigset_t __user *, oset, size_t, sigsetsize) | |
1da177e4 LT |
2019 | { |
2020 | int error = -EINVAL; | |
2021 | sigset_t old_set, new_set; | |
2022 | ||
2023 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2024 | if (sigsetsize != sizeof(sigset_t)) | |
2025 | goto out; | |
2026 | ||
2027 | if (set) { | |
2028 | error = -EFAULT; | |
2029 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2030 | goto out; | |
2031 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2032 | ||
2033 | error = sigprocmask(how, &new_set, &old_set); | |
2034 | if (error) | |
2035 | goto out; | |
2036 | if (oset) | |
2037 | goto set_old; | |
2038 | } else if (oset) { | |
2039 | spin_lock_irq(¤t->sighand->siglock); | |
2040 | old_set = current->blocked; | |
2041 | spin_unlock_irq(¤t->sighand->siglock); | |
2042 | ||
2043 | set_old: | |
2044 | error = -EFAULT; | |
2045 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2046 | goto out; | |
2047 | } | |
2048 | error = 0; | |
2049 | out: | |
2050 | return error; | |
2051 | } | |
2052 | ||
2053 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2054 | { | |
2055 | long error = -EINVAL; | |
2056 | sigset_t pending; | |
2057 | ||
2058 | if (sigsetsize > sizeof(sigset_t)) | |
2059 | goto out; | |
2060 | ||
2061 | spin_lock_irq(¤t->sighand->siglock); | |
2062 | sigorsets(&pending, ¤t->pending.signal, | |
2063 | ¤t->signal->shared_pending.signal); | |
2064 | spin_unlock_irq(¤t->sighand->siglock); | |
2065 | ||
2066 | /* Outside the lock because only this thread touches it. */ | |
2067 | sigandsets(&pending, ¤t->blocked, &pending); | |
2068 | ||
2069 | error = -EFAULT; | |
2070 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2071 | error = 0; | |
2072 | ||
2073 | out: | |
2074 | return error; | |
2075 | } | |
2076 | ||
17da2bd9 | 2077 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize) |
1da177e4 LT |
2078 | { |
2079 | return do_sigpending(set, sigsetsize); | |
2080 | } | |
2081 | ||
2082 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2083 | ||
2084 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2085 | { | |
2086 | int err; | |
2087 | ||
2088 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2089 | return -EFAULT; | |
2090 | if (from->si_code < 0) | |
2091 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2092 | ? -EFAULT : 0; | |
2093 | /* | |
2094 | * If you change siginfo_t structure, please be sure | |
2095 | * this code is fixed accordingly. | |
fba2afaa DL |
2096 | * Please remember to update the signalfd_copyinfo() function |
2097 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2098 | * It should never copy any pad contained in the structure |
2099 | * to avoid security leaks, but must copy the generic | |
2100 | * 3 ints plus the relevant union member. | |
2101 | */ | |
2102 | err = __put_user(from->si_signo, &to->si_signo); | |
2103 | err |= __put_user(from->si_errno, &to->si_errno); | |
2104 | err |= __put_user((short)from->si_code, &to->si_code); | |
2105 | switch (from->si_code & __SI_MASK) { | |
2106 | case __SI_KILL: | |
2107 | err |= __put_user(from->si_pid, &to->si_pid); | |
2108 | err |= __put_user(from->si_uid, &to->si_uid); | |
2109 | break; | |
2110 | case __SI_TIMER: | |
2111 | err |= __put_user(from->si_tid, &to->si_tid); | |
2112 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2113 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2114 | break; | |
2115 | case __SI_POLL: | |
2116 | err |= __put_user(from->si_band, &to->si_band); | |
2117 | err |= __put_user(from->si_fd, &to->si_fd); | |
2118 | break; | |
2119 | case __SI_FAULT: | |
2120 | err |= __put_user(from->si_addr, &to->si_addr); | |
2121 | #ifdef __ARCH_SI_TRAPNO | |
2122 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
2123 | #endif | |
2124 | break; | |
2125 | case __SI_CHLD: | |
2126 | err |= __put_user(from->si_pid, &to->si_pid); | |
2127 | err |= __put_user(from->si_uid, &to->si_uid); | |
2128 | err |= __put_user(from->si_status, &to->si_status); | |
2129 | err |= __put_user(from->si_utime, &to->si_utime); | |
2130 | err |= __put_user(from->si_stime, &to->si_stime); | |
2131 | break; | |
2132 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2133 | case __SI_MESGQ: /* But this is */ | |
2134 | err |= __put_user(from->si_pid, &to->si_pid); | |
2135 | err |= __put_user(from->si_uid, &to->si_uid); | |
2136 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2137 | break; | |
2138 | default: /* this is just in case for now ... */ | |
2139 | err |= __put_user(from->si_pid, &to->si_pid); | |
2140 | err |= __put_user(from->si_uid, &to->si_uid); | |
2141 | break; | |
2142 | } | |
2143 | return err; | |
2144 | } | |
2145 | ||
2146 | #endif | |
2147 | ||
17da2bd9 HC |
2148 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2149 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2150 | size_t, sigsetsize) | |
1da177e4 LT |
2151 | { |
2152 | int ret, sig; | |
2153 | sigset_t these; | |
2154 | struct timespec ts; | |
2155 | siginfo_t info; | |
2156 | long timeout = 0; | |
2157 | ||
2158 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2159 | if (sigsetsize != sizeof(sigset_t)) | |
2160 | return -EINVAL; | |
2161 | ||
2162 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2163 | return -EFAULT; | |
2164 | ||
2165 | /* | |
2166 | * Invert the set of allowed signals to get those we | |
2167 | * want to block. | |
2168 | */ | |
2169 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2170 | signotset(&these); | |
2171 | ||
2172 | if (uts) { | |
2173 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2174 | return -EFAULT; | |
2175 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2176 | || ts.tv_sec < 0) | |
2177 | return -EINVAL; | |
2178 | } | |
2179 | ||
2180 | spin_lock_irq(¤t->sighand->siglock); | |
2181 | sig = dequeue_signal(current, &these, &info); | |
2182 | if (!sig) { | |
2183 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2184 | if (uts) | |
2185 | timeout = (timespec_to_jiffies(&ts) | |
2186 | + (ts.tv_sec || ts.tv_nsec)); | |
2187 | ||
2188 | if (timeout) { | |
2189 | /* None ready -- temporarily unblock those we're | |
2190 | * interested while we are sleeping in so that we'll | |
2191 | * be awakened when they arrive. */ | |
2192 | current->real_blocked = current->blocked; | |
2193 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2194 | recalc_sigpending(); | |
2195 | spin_unlock_irq(¤t->sighand->siglock); | |
2196 | ||
75bcc8c5 | 2197 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2198 | |
1da177e4 LT |
2199 | spin_lock_irq(¤t->sighand->siglock); |
2200 | sig = dequeue_signal(current, &these, &info); | |
2201 | current->blocked = current->real_blocked; | |
2202 | siginitset(¤t->real_blocked, 0); | |
2203 | recalc_sigpending(); | |
2204 | } | |
2205 | } | |
2206 | spin_unlock_irq(¤t->sighand->siglock); | |
2207 | ||
2208 | if (sig) { | |
2209 | ret = sig; | |
2210 | if (uinfo) { | |
2211 | if (copy_siginfo_to_user(uinfo, &info)) | |
2212 | ret = -EFAULT; | |
2213 | } | |
2214 | } else { | |
2215 | ret = -EAGAIN; | |
2216 | if (timeout) | |
2217 | ret = -EINTR; | |
2218 | } | |
2219 | ||
2220 | return ret; | |
2221 | } | |
2222 | ||
17da2bd9 | 2223 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2224 | { |
2225 | struct siginfo info; | |
2226 | ||
2227 | info.si_signo = sig; | |
2228 | info.si_errno = 0; | |
2229 | info.si_code = SI_USER; | |
b488893a | 2230 | info.si_pid = task_tgid_vnr(current); |
76aac0e9 | 2231 | info.si_uid = current_uid(); |
1da177e4 LT |
2232 | |
2233 | return kill_something_info(sig, &info, pid); | |
2234 | } | |
2235 | ||
bc64efd2 | 2236 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
1da177e4 | 2237 | { |
1da177e4 | 2238 | int error; |
6dd69f10 | 2239 | struct siginfo info; |
1da177e4 | 2240 | struct task_struct *p; |
3547ff3a | 2241 | unsigned long flags; |
1da177e4 | 2242 | |
6dd69f10 | 2243 | error = -ESRCH; |
1da177e4 LT |
2244 | info.si_signo = sig; |
2245 | info.si_errno = 0; | |
2246 | info.si_code = SI_TKILL; | |
b488893a | 2247 | info.si_pid = task_tgid_vnr(current); |
76aac0e9 | 2248 | info.si_uid = current_uid(); |
1da177e4 | 2249 | |
3547ff3a | 2250 | rcu_read_lock(); |
228ebcbe | 2251 | p = find_task_by_vpid(pid); |
b488893a | 2252 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
1da177e4 LT |
2253 | error = check_kill_permission(sig, &info, p); |
2254 | /* | |
2255 | * The null signal is a permissions and process existence | |
2256 | * probe. No signal is actually delivered. | |
3547ff3a ON |
2257 | * |
2258 | * If lock_task_sighand() fails we pretend the task dies | |
2259 | * after receiving the signal. The window is tiny, and the | |
2260 | * signal is private anyway. | |
1da177e4 | 2261 | */ |
3547ff3a | 2262 | if (!error && sig && lock_task_sighand(p, &flags)) { |
1da177e4 | 2263 | error = specific_send_sig_info(sig, &info, p); |
3547ff3a | 2264 | unlock_task_sighand(p, &flags); |
1da177e4 LT |
2265 | } |
2266 | } | |
3547ff3a | 2267 | rcu_read_unlock(); |
6dd69f10 | 2268 | |
1da177e4 LT |
2269 | return error; |
2270 | } | |
2271 | ||
6dd69f10 VL |
2272 | /** |
2273 | * sys_tgkill - send signal to one specific thread | |
2274 | * @tgid: the thread group ID of the thread | |
2275 | * @pid: the PID of the thread | |
2276 | * @sig: signal to be sent | |
2277 | * | |
72fd4a35 | 2278 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2279 | * exists but it's not belonging to the target process anymore. This |
2280 | * method solves the problem of threads exiting and PIDs getting reused. | |
2281 | */ | |
bc64efd2 | 2282 | asmlinkage long sys_tgkill(pid_t tgid, pid_t pid, int sig) |
6dd69f10 VL |
2283 | { |
2284 | /* This is only valid for single tasks */ | |
2285 | if (pid <= 0 || tgid <= 0) | |
2286 | return -EINVAL; | |
2287 | ||
2288 | return do_tkill(tgid, pid, sig); | |
2289 | } | |
2290 | ||
1da177e4 LT |
2291 | /* |
2292 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2293 | */ | |
2294 | asmlinkage long | |
bc64efd2 | 2295 | sys_tkill(pid_t pid, int sig) |
1da177e4 | 2296 | { |
1da177e4 LT |
2297 | /* This is only valid for single tasks */ |
2298 | if (pid <= 0) | |
2299 | return -EINVAL; | |
2300 | ||
6dd69f10 | 2301 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2302 | } |
2303 | ||
2304 | asmlinkage long | |
bc64efd2 | 2305 | sys_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t __user *uinfo) |
1da177e4 LT |
2306 | { |
2307 | siginfo_t info; | |
2308 | ||
2309 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2310 | return -EFAULT; | |
2311 | ||
2312 | /* Not even root can pretend to send signals from the kernel. | |
2313 | Nor can they impersonate a kill(), which adds source info. */ | |
2314 | if (info.si_code >= 0) | |
2315 | return -EPERM; | |
2316 | info.si_signo = sig; | |
2317 | ||
2318 | /* POSIX.1b doesn't mention process groups. */ | |
2319 | return kill_proc_info(sig, &info, pid); | |
2320 | } | |
2321 | ||
88531f72 | 2322 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 2323 | { |
93585eea | 2324 | struct task_struct *t = current; |
1da177e4 | 2325 | struct k_sigaction *k; |
71fabd5e | 2326 | sigset_t mask; |
1da177e4 | 2327 | |
7ed20e1a | 2328 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2329 | return -EINVAL; |
2330 | ||
93585eea | 2331 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
2332 | |
2333 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2334 | if (oact) |
2335 | *oact = *k; | |
2336 | ||
2337 | if (act) { | |
9ac95f2f ON |
2338 | sigdelsetmask(&act->sa.sa_mask, |
2339 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2340 | *k = *act; |
1da177e4 LT |
2341 | /* |
2342 | * POSIX 3.3.1.3: | |
2343 | * "Setting a signal action to SIG_IGN for a signal that is | |
2344 | * pending shall cause the pending signal to be discarded, | |
2345 | * whether or not it is blocked." | |
2346 | * | |
2347 | * "Setting a signal action to SIG_DFL for a signal that is | |
2348 | * pending and whose default action is to ignore the signal | |
2349 | * (for example, SIGCHLD), shall cause the pending signal to | |
2350 | * be discarded, whether or not it is blocked" | |
2351 | */ | |
35de254d | 2352 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
2353 | sigemptyset(&mask); |
2354 | sigaddset(&mask, sig); | |
2355 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2356 | do { |
71fabd5e | 2357 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2358 | t = next_thread(t); |
2359 | } while (t != current); | |
1da177e4 | 2360 | } |
1da177e4 LT |
2361 | } |
2362 | ||
2363 | spin_unlock_irq(¤t->sighand->siglock); | |
2364 | return 0; | |
2365 | } | |
2366 | ||
2367 | int | |
2368 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2369 | { | |
2370 | stack_t oss; | |
2371 | int error; | |
2372 | ||
2373 | if (uoss) { | |
2374 | oss.ss_sp = (void __user *) current->sas_ss_sp; | |
2375 | oss.ss_size = current->sas_ss_size; | |
2376 | oss.ss_flags = sas_ss_flags(sp); | |
2377 | } | |
2378 | ||
2379 | if (uss) { | |
2380 | void __user *ss_sp; | |
2381 | size_t ss_size; | |
2382 | int ss_flags; | |
2383 | ||
2384 | error = -EFAULT; | |
2385 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss)) | |
2386 | || __get_user(ss_sp, &uss->ss_sp) | |
2387 | || __get_user(ss_flags, &uss->ss_flags) | |
2388 | || __get_user(ss_size, &uss->ss_size)) | |
2389 | goto out; | |
2390 | ||
2391 | error = -EPERM; | |
2392 | if (on_sig_stack(sp)) | |
2393 | goto out; | |
2394 | ||
2395 | error = -EINVAL; | |
2396 | /* | |
2397 | * | |
2398 | * Note - this code used to test ss_flags incorrectly | |
2399 | * old code may have been written using ss_flags==0 | |
2400 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2401 | * way that worked) - this fix preserves that older | |
2402 | * mechanism | |
2403 | */ | |
2404 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2405 | goto out; | |
2406 | ||
2407 | if (ss_flags == SS_DISABLE) { | |
2408 | ss_size = 0; | |
2409 | ss_sp = NULL; | |
2410 | } else { | |
2411 | error = -ENOMEM; | |
2412 | if (ss_size < MINSIGSTKSZ) | |
2413 | goto out; | |
2414 | } | |
2415 | ||
2416 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2417 | current->sas_ss_size = ss_size; | |
2418 | } | |
2419 | ||
2420 | if (uoss) { | |
2421 | error = -EFAULT; | |
2422 | if (copy_to_user(uoss, &oss, sizeof(oss))) | |
2423 | goto out; | |
2424 | } | |
2425 | ||
2426 | error = 0; | |
2427 | out: | |
2428 | return error; | |
2429 | } | |
2430 | ||
2431 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2432 | ||
b290ebe2 | 2433 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 LT |
2434 | { |
2435 | return do_sigpending(set, sizeof(*set)); | |
2436 | } | |
2437 | ||
2438 | #endif | |
2439 | ||
2440 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2441 | /* Some platforms have their own version with special arguments others | |
2442 | support only sys_rt_sigprocmask. */ | |
2443 | ||
b290ebe2 HC |
2444 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set, |
2445 | old_sigset_t __user *, oset) | |
1da177e4 LT |
2446 | { |
2447 | int error; | |
2448 | old_sigset_t old_set, new_set; | |
2449 | ||
2450 | if (set) { | |
2451 | error = -EFAULT; | |
2452 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2453 | goto out; | |
2454 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2455 | ||
2456 | spin_lock_irq(¤t->sighand->siglock); | |
2457 | old_set = current->blocked.sig[0]; | |
2458 | ||
2459 | error = 0; | |
2460 | switch (how) { | |
2461 | default: | |
2462 | error = -EINVAL; | |
2463 | break; | |
2464 | case SIG_BLOCK: | |
2465 | sigaddsetmask(¤t->blocked, new_set); | |
2466 | break; | |
2467 | case SIG_UNBLOCK: | |
2468 | sigdelsetmask(¤t->blocked, new_set); | |
2469 | break; | |
2470 | case SIG_SETMASK: | |
2471 | current->blocked.sig[0] = new_set; | |
2472 | break; | |
2473 | } | |
2474 | ||
2475 | recalc_sigpending(); | |
2476 | spin_unlock_irq(¤t->sighand->siglock); | |
2477 | if (error) | |
2478 | goto out; | |
2479 | if (oset) | |
2480 | goto set_old; | |
2481 | } else if (oset) { | |
2482 | old_set = current->blocked.sig[0]; | |
2483 | set_old: | |
2484 | error = -EFAULT; | |
2485 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2486 | goto out; | |
2487 | } | |
2488 | error = 0; | |
2489 | out: | |
2490 | return error; | |
2491 | } | |
2492 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2493 | ||
2494 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
2495 | asmlinkage long | |
2496 | sys_rt_sigaction(int sig, | |
2497 | const struct sigaction __user *act, | |
2498 | struct sigaction __user *oact, | |
2499 | size_t sigsetsize) | |
2500 | { | |
2501 | struct k_sigaction new_sa, old_sa; | |
2502 | int ret = -EINVAL; | |
2503 | ||
2504 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2505 | if (sigsetsize != sizeof(sigset_t)) | |
2506 | goto out; | |
2507 | ||
2508 | if (act) { | |
2509 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2510 | return -EFAULT; | |
2511 | } | |
2512 | ||
2513 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2514 | ||
2515 | if (!ret && oact) { | |
2516 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2517 | return -EFAULT; | |
2518 | } | |
2519 | out: | |
2520 | return ret; | |
2521 | } | |
2522 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2523 | ||
2524 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2525 | ||
2526 | /* | |
2527 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2528 | */ | |
2529 | asmlinkage long | |
2530 | sys_sgetmask(void) | |
2531 | { | |
2532 | /* SMP safe */ | |
2533 | return current->blocked.sig[0]; | |
2534 | } | |
2535 | ||
2536 | asmlinkage long | |
2537 | sys_ssetmask(int newmask) | |
2538 | { | |
2539 | int old; | |
2540 | ||
2541 | spin_lock_irq(¤t->sighand->siglock); | |
2542 | old = current->blocked.sig[0]; | |
2543 | ||
2544 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2545 | sigmask(SIGSTOP))); | |
2546 | recalc_sigpending(); | |
2547 | spin_unlock_irq(¤t->sighand->siglock); | |
2548 | ||
2549 | return old; | |
2550 | } | |
2551 | #endif /* __ARCH_WANT_SGETMASK */ | |
2552 | ||
2553 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2554 | /* | |
2555 | * For backwards compatibility. Functionality superseded by sigaction. | |
2556 | */ | |
2ed7c03e | 2557 | asmlinkage long |
1da177e4 LT |
2558 | sys_signal(int sig, __sighandler_t handler) |
2559 | { | |
2560 | struct k_sigaction new_sa, old_sa; | |
2561 | int ret; | |
2562 | ||
2563 | new_sa.sa.sa_handler = handler; | |
2564 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2565 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2566 | |
2567 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2568 | ||
2569 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2570 | } | |
2571 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2572 | ||
2573 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2574 | ||
2575 | asmlinkage long | |
2576 | sys_pause(void) | |
2577 | { | |
2578 | current->state = TASK_INTERRUPTIBLE; | |
2579 | schedule(); | |
2580 | return -ERESTARTNOHAND; | |
2581 | } | |
2582 | ||
2583 | #endif | |
2584 | ||
150256d8 DW |
2585 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
2586 | asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize) | |
2587 | { | |
2588 | sigset_t newset; | |
2589 | ||
2590 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2591 | if (sigsetsize != sizeof(sigset_t)) | |
2592 | return -EINVAL; | |
2593 | ||
2594 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2595 | return -EFAULT; | |
2596 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2597 | ||
2598 | spin_lock_irq(¤t->sighand->siglock); | |
2599 | current->saved_sigmask = current->blocked; | |
2600 | current->blocked = newset; | |
2601 | recalc_sigpending(); | |
2602 | spin_unlock_irq(¤t->sighand->siglock); | |
2603 | ||
2604 | current->state = TASK_INTERRUPTIBLE; | |
2605 | schedule(); | |
4e4c22c7 | 2606 | set_restore_sigmask(); |
150256d8 DW |
2607 | return -ERESTARTNOHAND; |
2608 | } | |
2609 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2610 | ||
f269fdd1 DH |
2611 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2612 | { | |
2613 | return NULL; | |
2614 | } | |
2615 | ||
1da177e4 LT |
2616 | void __init signals_init(void) |
2617 | { | |
0a31bd5f | 2618 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2619 | } |