]>
Commit | Line | Data |
---|---|---|
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> |
f84d49b2 | 25 | #include <linux/ratelimit.h> |
35de254d | 26 | #include <linux/tracehook.h> |
c59ede7b | 27 | #include <linux/capability.h> |
7dfb7103 | 28 | #include <linux/freezer.h> |
84d73786 SB |
29 | #include <linux/pid_namespace.h> |
30 | #include <linux/nsproxy.h> | |
d1eb650f MH |
31 | #define CREATE_TRACE_POINTS |
32 | #include <trace/events/signal.h> | |
84d73786 | 33 | |
1da177e4 LT |
34 | #include <asm/param.h> |
35 | #include <asm/uaccess.h> | |
36 | #include <asm/unistd.h> | |
37 | #include <asm/siginfo.h> | |
e1396065 | 38 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
39 | |
40 | /* | |
41 | * SLAB caches for signal bits. | |
42 | */ | |
43 | ||
e18b890b | 44 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 45 | |
f84d49b2 NO |
46 | int print_fatal_signals __read_mostly; |
47 | ||
35de254d | 48 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 49 | { |
35de254d RM |
50 | return t->sighand->action[sig - 1].sa.sa_handler; |
51 | } | |
93585eea | 52 | |
35de254d RM |
53 | static int sig_handler_ignored(void __user *handler, int sig) |
54 | { | |
93585eea | 55 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
56 | return handler == SIG_IGN || |
57 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
58 | } | |
1da177e4 | 59 | |
921cf9f6 SB |
60 | static int sig_task_ignored(struct task_struct *t, int sig, |
61 | int from_ancestor_ns) | |
1da177e4 | 62 | { |
35de254d | 63 | void __user *handler; |
1da177e4 | 64 | |
f008faff ON |
65 | handler = sig_handler(t, sig); |
66 | ||
67 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
921cf9f6 | 68 | handler == SIG_DFL && !from_ancestor_ns) |
f008faff ON |
69 | return 1; |
70 | ||
71 | return sig_handler_ignored(handler, sig); | |
72 | } | |
73 | ||
921cf9f6 | 74 | static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns) |
f008faff | 75 | { |
1da177e4 LT |
76 | /* |
77 | * Blocked signals are never ignored, since the | |
78 | * signal handler may change by the time it is | |
79 | * unblocked. | |
80 | */ | |
325d22df | 81 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
82 | return 0; |
83 | ||
921cf9f6 | 84 | if (!sig_task_ignored(t, sig, from_ancestor_ns)) |
35de254d RM |
85 | return 0; |
86 | ||
87 | /* | |
88 | * Tracers may want to know about even ignored signals. | |
89 | */ | |
43918f2b | 90 | return !tracehook_consider_ignored_signal(t, sig); |
1da177e4 LT |
91 | } |
92 | ||
93 | /* | |
94 | * Re-calculate pending state from the set of locally pending | |
95 | * signals, globally pending signals, and blocked signals. | |
96 | */ | |
97 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
98 | { | |
99 | unsigned long ready; | |
100 | long i; | |
101 | ||
102 | switch (_NSIG_WORDS) { | |
103 | default: | |
104 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
105 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
106 | break; | |
107 | ||
108 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
109 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
110 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
111 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
112 | break; | |
113 | ||
114 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
115 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
116 | break; | |
117 | ||
118 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
119 | } | |
120 | return ready != 0; | |
121 | } | |
122 | ||
123 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
124 | ||
7bb44ade | 125 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 LT |
126 | { |
127 | if (t->signal->group_stop_count > 0 || | |
128 | PENDING(&t->pending, &t->blocked) || | |
7bb44ade | 129 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 130 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
131 | return 1; |
132 | } | |
b74d0deb RM |
133 | /* |
134 | * We must never clear the flag in another thread, or in current | |
135 | * when it's possible the current syscall is returning -ERESTART*. | |
136 | * So we don't clear it here, and only callers who know they should do. | |
137 | */ | |
7bb44ade RM |
138 | return 0; |
139 | } | |
140 | ||
141 | /* | |
142 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
143 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
144 | */ | |
145 | void recalc_sigpending_and_wake(struct task_struct *t) | |
146 | { | |
147 | if (recalc_sigpending_tsk(t)) | |
148 | signal_wake_up(t, 0); | |
1da177e4 LT |
149 | } |
150 | ||
151 | void recalc_sigpending(void) | |
152 | { | |
b787f7ba RM |
153 | if (unlikely(tracehook_force_sigpending())) |
154 | set_thread_flag(TIF_SIGPENDING); | |
155 | else if (!recalc_sigpending_tsk(current) && !freezing(current)) | |
b74d0deb RM |
156 | clear_thread_flag(TIF_SIGPENDING); |
157 | ||
1da177e4 LT |
158 | } |
159 | ||
160 | /* Given the mask, find the first available signal that should be serviced. */ | |
161 | ||
a27341cd LT |
162 | #define SYNCHRONOUS_MASK \ |
163 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
164 | sigmask(SIGTRAP) | sigmask(SIGFPE)) | |
165 | ||
fba2afaa | 166 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
167 | { |
168 | unsigned long i, *s, *m, x; | |
169 | int sig = 0; | |
f84d49b2 | 170 | |
1da177e4 LT |
171 | s = pending->signal.sig; |
172 | m = mask->sig; | |
a27341cd LT |
173 | |
174 | /* | |
175 | * Handle the first word specially: it contains the | |
176 | * synchronous signals that need to be dequeued first. | |
177 | */ | |
178 | x = *s &~ *m; | |
179 | if (x) { | |
180 | if (x & SYNCHRONOUS_MASK) | |
181 | x &= SYNCHRONOUS_MASK; | |
182 | sig = ffz(~x) + 1; | |
183 | return sig; | |
184 | } | |
185 | ||
1da177e4 LT |
186 | switch (_NSIG_WORDS) { |
187 | default: | |
a27341cd LT |
188 | for (i = 1; i < _NSIG_WORDS; ++i) { |
189 | x = *++s &~ *++m; | |
190 | if (!x) | |
191 | continue; | |
192 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
193 | break; | |
194 | } | |
1da177e4 LT |
195 | break; |
196 | ||
a27341cd LT |
197 | case 2: |
198 | x = s[1] &~ m[1]; | |
199 | if (!x) | |
1da177e4 | 200 | break; |
a27341cd | 201 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
202 | break; |
203 | ||
a27341cd LT |
204 | case 1: |
205 | /* Nothing to do */ | |
1da177e4 LT |
206 | break; |
207 | } | |
f84d49b2 | 208 | |
1da177e4 LT |
209 | return sig; |
210 | } | |
211 | ||
f84d49b2 NO |
212 | static inline void print_dropped_signal(int sig) |
213 | { | |
214 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
215 | ||
216 | if (!print_fatal_signals) | |
217 | return; | |
218 | ||
219 | if (!__ratelimit(&ratelimit_state)) | |
220 | return; | |
221 | ||
222 | printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", | |
223 | current->comm, current->pid, sig); | |
224 | } | |
225 | ||
c69e8d9c DH |
226 | /* |
227 | * allocate a new signal queue record | |
228 | * - this may be called without locks if and only if t == current, otherwise an | |
d84f4f99 | 229 | * appopriate lock must be held to stop the target task from exiting |
c69e8d9c | 230 | */ |
f84d49b2 NO |
231 | static struct sigqueue * |
232 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
233 | { |
234 | struct sigqueue *q = NULL; | |
10b1fbdb | 235 | struct user_struct *user; |
1da177e4 | 236 | |
10b1fbdb | 237 | /* |
7cf7db8d TG |
238 | * Protect access to @t credentials. This can go away when all |
239 | * callers hold rcu read lock. | |
10b1fbdb | 240 | */ |
7cf7db8d | 241 | rcu_read_lock(); |
d84f4f99 | 242 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 243 | atomic_inc(&user->sigpending); |
7cf7db8d | 244 | rcu_read_unlock(); |
f84d49b2 | 245 | |
1da177e4 | 246 | if (override_rlimit || |
10b1fbdb | 247 | atomic_read(&user->sigpending) <= |
78d7d407 | 248 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 249 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
250 | } else { |
251 | print_dropped_signal(sig); | |
252 | } | |
253 | ||
1da177e4 | 254 | if (unlikely(q == NULL)) { |
10b1fbdb | 255 | atomic_dec(&user->sigpending); |
d84f4f99 | 256 | free_uid(user); |
1da177e4 LT |
257 | } else { |
258 | INIT_LIST_HEAD(&q->list); | |
259 | q->flags = 0; | |
d84f4f99 | 260 | q->user = user; |
1da177e4 | 261 | } |
d84f4f99 DH |
262 | |
263 | return q; | |
1da177e4 LT |
264 | } |
265 | ||
514a01b8 | 266 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
267 | { |
268 | if (q->flags & SIGQUEUE_PREALLOC) | |
269 | return; | |
270 | atomic_dec(&q->user->sigpending); | |
271 | free_uid(q->user); | |
272 | kmem_cache_free(sigqueue_cachep, q); | |
273 | } | |
274 | ||
6a14c5c9 | 275 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
276 | { |
277 | struct sigqueue *q; | |
278 | ||
279 | sigemptyset(&queue->signal); | |
280 | while (!list_empty(&queue->list)) { | |
281 | q = list_entry(queue->list.next, struct sigqueue , list); | |
282 | list_del_init(&q->list); | |
283 | __sigqueue_free(q); | |
284 | } | |
285 | } | |
286 | ||
287 | /* | |
288 | * Flush all pending signals for a task. | |
289 | */ | |
3bcac026 DH |
290 | void __flush_signals(struct task_struct *t) |
291 | { | |
292 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
293 | flush_sigqueue(&t->pending); | |
294 | flush_sigqueue(&t->signal->shared_pending); | |
295 | } | |
296 | ||
c81addc9 | 297 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
298 | { |
299 | unsigned long flags; | |
300 | ||
301 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
3bcac026 | 302 | __flush_signals(t); |
1da177e4 LT |
303 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
304 | } | |
305 | ||
cbaffba1 ON |
306 | static void __flush_itimer_signals(struct sigpending *pending) |
307 | { | |
308 | sigset_t signal, retain; | |
309 | struct sigqueue *q, *n; | |
310 | ||
311 | signal = pending->signal; | |
312 | sigemptyset(&retain); | |
313 | ||
314 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
315 | int sig = q->info.si_signo; | |
316 | ||
317 | if (likely(q->info.si_code != SI_TIMER)) { | |
318 | sigaddset(&retain, sig); | |
319 | } else { | |
320 | sigdelset(&signal, sig); | |
321 | list_del_init(&q->list); | |
322 | __sigqueue_free(q); | |
323 | } | |
324 | } | |
325 | ||
326 | sigorsets(&pending->signal, &signal, &retain); | |
327 | } | |
328 | ||
329 | void flush_itimer_signals(void) | |
330 | { | |
331 | struct task_struct *tsk = current; | |
332 | unsigned long flags; | |
333 | ||
334 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
335 | __flush_itimer_signals(&tsk->pending); | |
336 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
337 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
338 | } | |
339 | ||
10ab825b ON |
340 | void ignore_signals(struct task_struct *t) |
341 | { | |
342 | int i; | |
343 | ||
344 | for (i = 0; i < _NSIG; ++i) | |
345 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
346 | ||
347 | flush_signals(t); | |
348 | } | |
349 | ||
1da177e4 LT |
350 | /* |
351 | * Flush all handlers for a task. | |
352 | */ | |
353 | ||
354 | void | |
355 | flush_signal_handlers(struct task_struct *t, int force_default) | |
356 | { | |
357 | int i; | |
358 | struct k_sigaction *ka = &t->sighand->action[0]; | |
359 | for (i = _NSIG ; i != 0 ; i--) { | |
360 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
361 | ka->sa.sa_handler = SIG_DFL; | |
362 | ka->sa.sa_flags = 0; | |
363 | sigemptyset(&ka->sa.sa_mask); | |
364 | ka++; | |
365 | } | |
366 | } | |
367 | ||
abd4f750 MAS |
368 | int unhandled_signal(struct task_struct *tsk, int sig) |
369 | { | |
445a91d2 | 370 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 371 | if (is_global_init(tsk)) |
abd4f750 | 372 | return 1; |
445a91d2 | 373 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 374 | return 0; |
43918f2b | 375 | return !tracehook_consider_fatal_signal(tsk, sig); |
abd4f750 MAS |
376 | } |
377 | ||
1da177e4 LT |
378 | |
379 | /* Notify the system that a driver wants to block all signals for this | |
380 | * process, and wants to be notified if any signals at all were to be | |
381 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
382 | * signal will be acted upon after all. If the notifier routine returns 0, | |
383 | * then then signal will be blocked. Only one block per process is | |
384 | * allowed. priv is a pointer to private data that the notifier routine | |
385 | * can use to determine if the signal should be blocked or not. */ | |
386 | ||
387 | void | |
388 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
389 | { | |
390 | unsigned long flags; | |
391 | ||
392 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
393 | current->notifier_mask = mask; | |
394 | current->notifier_data = priv; | |
395 | current->notifier = notifier; | |
396 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
397 | } | |
398 | ||
399 | /* Notify the system that blocking has ended. */ | |
400 | ||
401 | void | |
402 | unblock_all_signals(void) | |
403 | { | |
404 | unsigned long flags; | |
405 | ||
406 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
407 | current->notifier = NULL; | |
408 | current->notifier_data = NULL; | |
409 | recalc_sigpending(); | |
410 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
411 | } | |
412 | ||
100360f0 | 413 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
414 | { |
415 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 416 | |
1da177e4 LT |
417 | /* |
418 | * Collect the siginfo appropriate to this signal. Check if | |
419 | * there is another siginfo for the same signal. | |
420 | */ | |
421 | list_for_each_entry(q, &list->list, list) { | |
422 | if (q->info.si_signo == sig) { | |
d4434207 ON |
423 | if (first) |
424 | goto still_pending; | |
1da177e4 LT |
425 | first = q; |
426 | } | |
427 | } | |
d4434207 ON |
428 | |
429 | sigdelset(&list->signal, sig); | |
430 | ||
1da177e4 | 431 | if (first) { |
d4434207 | 432 | still_pending: |
1da177e4 LT |
433 | list_del_init(&first->list); |
434 | copy_siginfo(info, &first->info); | |
435 | __sigqueue_free(first); | |
1da177e4 | 436 | } else { |
1da177e4 LT |
437 | /* Ok, it wasn't in the queue. This must be |
438 | a fast-pathed signal or we must have been | |
439 | out of queue space. So zero out the info. | |
440 | */ | |
1da177e4 LT |
441 | info->si_signo = sig; |
442 | info->si_errno = 0; | |
7486e5d9 | 443 | info->si_code = SI_USER; |
1da177e4 LT |
444 | info->si_pid = 0; |
445 | info->si_uid = 0; | |
446 | } | |
1da177e4 LT |
447 | } |
448 | ||
449 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
450 | siginfo_t *info) | |
451 | { | |
27d91e07 | 452 | int sig = next_signal(pending, mask); |
1da177e4 | 453 | |
1da177e4 LT |
454 | if (sig) { |
455 | if (current->notifier) { | |
456 | if (sigismember(current->notifier_mask, sig)) { | |
457 | if (!(current->notifier)(current->notifier_data)) { | |
458 | clear_thread_flag(TIF_SIGPENDING); | |
459 | return 0; | |
460 | } | |
461 | } | |
462 | } | |
463 | ||
100360f0 | 464 | collect_signal(sig, pending, info); |
1da177e4 | 465 | } |
1da177e4 LT |
466 | |
467 | return sig; | |
468 | } | |
469 | ||
470 | /* | |
471 | * Dequeue a signal and return the element to the caller, which is | |
472 | * expected to free it. | |
473 | * | |
474 | * All callers have to hold the siglock. | |
475 | */ | |
476 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
477 | { | |
c5363d03 | 478 | int signr; |
caec4e8d BH |
479 | |
480 | /* We only dequeue private signals from ourselves, we don't let | |
481 | * signalfd steal them | |
482 | */ | |
b8fceee1 | 483 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 484 | if (!signr) { |
1da177e4 LT |
485 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
486 | mask, info); | |
8bfd9a7a TG |
487 | /* |
488 | * itimer signal ? | |
489 | * | |
490 | * itimers are process shared and we restart periodic | |
491 | * itimers in the signal delivery path to prevent DoS | |
492 | * attacks in the high resolution timer case. This is | |
493 | * compliant with the old way of self restarting | |
494 | * itimers, as the SIGALRM is a legacy signal and only | |
495 | * queued once. Changing the restart behaviour to | |
496 | * restart the timer in the signal dequeue path is | |
497 | * reducing the timer noise on heavy loaded !highres | |
498 | * systems too. | |
499 | */ | |
500 | if (unlikely(signr == SIGALRM)) { | |
501 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
502 | ||
503 | if (!hrtimer_is_queued(tmr) && | |
504 | tsk->signal->it_real_incr.tv64 != 0) { | |
505 | hrtimer_forward(tmr, tmr->base->get_time(), | |
506 | tsk->signal->it_real_incr); | |
507 | hrtimer_restart(tmr); | |
508 | } | |
509 | } | |
510 | } | |
c5363d03 | 511 | |
b8fceee1 | 512 | recalc_sigpending(); |
c5363d03 PE |
513 | if (!signr) |
514 | return 0; | |
515 | ||
516 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
517 | /* |
518 | * Set a marker that we have dequeued a stop signal. Our | |
519 | * caller might release the siglock and then the pending | |
520 | * stop signal it is about to process is no longer in the | |
521 | * pending bitmasks, but must still be cleared by a SIGCONT | |
522 | * (and overruled by a SIGKILL). So those cases clear this | |
523 | * shared flag after we've set it. Note that this flag may | |
524 | * remain set after the signal we return is ignored or | |
525 | * handled. That doesn't matter because its only purpose | |
526 | * is to alert stop-signal processing code when another | |
527 | * processor has come along and cleared the flag. | |
528 | */ | |
92413d77 | 529 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; |
8bfd9a7a | 530 | } |
c5363d03 | 531 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
532 | /* |
533 | * Release the siglock to ensure proper locking order | |
534 | * of timer locks outside of siglocks. Note, we leave | |
535 | * irqs disabled here, since the posix-timers code is | |
536 | * about to disable them again anyway. | |
537 | */ | |
538 | spin_unlock(&tsk->sighand->siglock); | |
539 | do_schedule_next_timer(info); | |
540 | spin_lock(&tsk->sighand->siglock); | |
541 | } | |
542 | return signr; | |
543 | } | |
544 | ||
545 | /* | |
546 | * Tell a process that it has a new active signal.. | |
547 | * | |
548 | * NOTE! we rely on the previous spin_lock to | |
549 | * lock interrupts for us! We can only be called with | |
550 | * "siglock" held, and the local interrupt must | |
551 | * have been disabled when that got acquired! | |
552 | * | |
553 | * No need to set need_resched since signal event passing | |
554 | * goes through ->blocked | |
555 | */ | |
556 | void signal_wake_up(struct task_struct *t, int resume) | |
557 | { | |
558 | unsigned int mask; | |
559 | ||
560 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
561 | ||
562 | /* | |
f021a3c2 MW |
563 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
564 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
565 | * executing another processor and just now entering stopped state. |
566 | * By using wake_up_state, we ensure the process will wake up and | |
567 | * handle its death signal. | |
568 | */ | |
569 | mask = TASK_INTERRUPTIBLE; | |
570 | if (resume) | |
f021a3c2 | 571 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
572 | if (!wake_up_state(t, mask)) |
573 | kick_process(t); | |
574 | } | |
575 | ||
71fabd5e GA |
576 | /* |
577 | * Remove signals in mask from the pending set and queue. | |
578 | * Returns 1 if any signals were found. | |
579 | * | |
580 | * All callers must be holding the siglock. | |
581 | * | |
582 | * This version takes a sigset mask and looks at all signals, | |
583 | * not just those in the first mask word. | |
584 | */ | |
585 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
586 | { | |
587 | struct sigqueue *q, *n; | |
588 | sigset_t m; | |
589 | ||
590 | sigandsets(&m, mask, &s->signal); | |
591 | if (sigisemptyset(&m)) | |
592 | return 0; | |
593 | ||
594 | signandsets(&s->signal, &s->signal, mask); | |
595 | list_for_each_entry_safe(q, n, &s->list, list) { | |
596 | if (sigismember(mask, q->info.si_signo)) { | |
597 | list_del_init(&q->list); | |
598 | __sigqueue_free(q); | |
599 | } | |
600 | } | |
601 | return 1; | |
602 | } | |
1da177e4 LT |
603 | /* |
604 | * Remove signals in mask from the pending set and queue. | |
605 | * Returns 1 if any signals were found. | |
606 | * | |
607 | * All callers must be holding the siglock. | |
608 | */ | |
609 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
610 | { | |
611 | struct sigqueue *q, *n; | |
612 | ||
613 | if (!sigtestsetmask(&s->signal, mask)) | |
614 | return 0; | |
615 | ||
616 | sigdelsetmask(&s->signal, mask); | |
617 | list_for_each_entry_safe(q, n, &s->list, list) { | |
618 | if (q->info.si_signo < SIGRTMIN && | |
619 | (mask & sigmask(q->info.si_signo))) { | |
620 | list_del_init(&q->list); | |
621 | __sigqueue_free(q); | |
622 | } | |
623 | } | |
624 | return 1; | |
625 | } | |
626 | ||
614c517d ON |
627 | static inline int is_si_special(const struct siginfo *info) |
628 | { | |
629 | return info <= SEND_SIG_FORCED; | |
630 | } | |
631 | ||
632 | static inline bool si_fromuser(const struct siginfo *info) | |
633 | { | |
634 | return info == SEND_SIG_NOINFO || | |
635 | (!is_si_special(info) && SI_FROMUSER(info)); | |
636 | } | |
637 | ||
39fd3393 SH |
638 | /* |
639 | * called with RCU read lock from check_kill_permission() | |
640 | */ | |
641 | static int kill_ok_by_cred(struct task_struct *t) | |
642 | { | |
643 | const struct cred *cred = current_cred(); | |
644 | const struct cred *tcred = __task_cred(t); | |
645 | ||
646 | if (cred->user->user_ns == tcred->user->user_ns && | |
647 | (cred->euid == tcred->suid || | |
648 | cred->euid == tcred->uid || | |
649 | cred->uid == tcred->suid || | |
650 | cred->uid == tcred->uid)) | |
651 | return 1; | |
652 | ||
653 | if (ns_capable(tcred->user->user_ns, CAP_KILL)) | |
654 | return 1; | |
655 | ||
656 | return 0; | |
657 | } | |
658 | ||
1da177e4 LT |
659 | /* |
660 | * Bad permissions for sending the signal | |
694f690d | 661 | * - the caller must hold the RCU read lock |
1da177e4 LT |
662 | */ |
663 | static int check_kill_permission(int sig, struct siginfo *info, | |
664 | struct task_struct *t) | |
665 | { | |
2e2ba22e | 666 | struct pid *sid; |
3b5e9e53 ON |
667 | int error; |
668 | ||
7ed20e1a | 669 | if (!valid_signal(sig)) |
3b5e9e53 ON |
670 | return -EINVAL; |
671 | ||
614c517d | 672 | if (!si_fromuser(info)) |
3b5e9e53 | 673 | return 0; |
e54dc243 | 674 | |
3b5e9e53 ON |
675 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
676 | if (error) | |
1da177e4 | 677 | return error; |
3b5e9e53 | 678 | |
065add39 | 679 | if (!same_thread_group(current, t) && |
39fd3393 | 680 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
681 | switch (sig) { |
682 | case SIGCONT: | |
2e2ba22e | 683 | sid = task_session(t); |
2e2ba22e ON |
684 | /* |
685 | * We don't return the error if sid == NULL. The | |
686 | * task was unhashed, the caller must notice this. | |
687 | */ | |
688 | if (!sid || sid == task_session(current)) | |
689 | break; | |
690 | default: | |
691 | return -EPERM; | |
692 | } | |
693 | } | |
c2f0c7c3 | 694 | |
e54dc243 | 695 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
696 | } |
697 | ||
1da177e4 | 698 | /* |
7e695a5e ON |
699 | * Handle magic process-wide effects of stop/continue signals. Unlike |
700 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
701 | * time regardless of blocking, ignoring, or handling. This does the |
702 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
703 | * signals. The process stop is done as a signal action for SIG_DFL. |
704 | * | |
705 | * Returns true if the signal should be actually delivered, otherwise | |
706 | * it should be dropped. | |
1da177e4 | 707 | */ |
921cf9f6 | 708 | static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns) |
1da177e4 | 709 | { |
ad16a460 | 710 | struct signal_struct *signal = p->signal; |
1da177e4 LT |
711 | struct task_struct *t; |
712 | ||
7e695a5e | 713 | if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) { |
1da177e4 | 714 | /* |
7e695a5e | 715 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 716 | */ |
7e695a5e | 717 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
718 | /* |
719 | * This is a stop signal. Remove SIGCONT from all queues. | |
720 | */ | |
ad16a460 | 721 | rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); |
1da177e4 LT |
722 | t = p; |
723 | do { | |
724 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
ad16a460 | 725 | } while_each_thread(p, t); |
1da177e4 | 726 | } else if (sig == SIGCONT) { |
fc321d2e | 727 | unsigned int why; |
1da177e4 LT |
728 | /* |
729 | * Remove all stop signals from all queues, | |
730 | * and wake all threads. | |
731 | */ | |
ad16a460 | 732 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
733 | t = p; |
734 | do { | |
735 | unsigned int state; | |
736 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
1da177e4 LT |
737 | /* |
738 | * If there is a handler for SIGCONT, we must make | |
739 | * sure that no thread returns to user mode before | |
740 | * we post the signal, in case it was the only | |
741 | * thread eligible to run the signal handler--then | |
742 | * it must not do anything between resuming and | |
743 | * running the handler. With the TIF_SIGPENDING | |
744 | * flag set, the thread will pause and acquire the | |
745 | * siglock that we hold now and until we've queued | |
fc321d2e | 746 | * the pending signal. |
1da177e4 LT |
747 | * |
748 | * Wake up the stopped thread _after_ setting | |
749 | * TIF_SIGPENDING | |
750 | */ | |
f021a3c2 | 751 | state = __TASK_STOPPED; |
1da177e4 LT |
752 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { |
753 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
754 | state |= TASK_INTERRUPTIBLE; | |
755 | } | |
756 | wake_up_state(t, state); | |
ad16a460 | 757 | } while_each_thread(p, t); |
1da177e4 | 758 | |
fc321d2e ON |
759 | /* |
760 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
761 | * | |
762 | * If we were in the middle of a group stop, we pretend it | |
763 | * was already finished, and then continued. Since SIGCHLD | |
764 | * doesn't queue we report only CLD_STOPPED, as if the next | |
765 | * CLD_CONTINUED was dropped. | |
766 | */ | |
767 | why = 0; | |
ad16a460 | 768 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 769 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 770 | else if (signal->group_stop_count) |
fc321d2e ON |
771 | why |= SIGNAL_CLD_STOPPED; |
772 | ||
773 | if (why) { | |
021e1ae3 | 774 | /* |
ae6d2ed7 | 775 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
776 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
777 | * notify its parent. See get_signal_to_deliver(). | |
778 | */ | |
ad16a460 ON |
779 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
780 | signal->group_stop_count = 0; | |
781 | signal->group_exit_code = 0; | |
1da177e4 LT |
782 | } else { |
783 | /* | |
784 | * We are not stopped, but there could be a stop | |
785 | * signal in the middle of being processed after | |
786 | * being removed from the queue. Clear that too. | |
787 | */ | |
ad16a460 | 788 | signal->flags &= ~SIGNAL_STOP_DEQUEUED; |
1da177e4 | 789 | } |
1da177e4 | 790 | } |
7e695a5e | 791 | |
921cf9f6 | 792 | return !sig_ignored(p, sig, from_ancestor_ns); |
1da177e4 LT |
793 | } |
794 | ||
71f11dc0 ON |
795 | /* |
796 | * Test if P wants to take SIG. After we've checked all threads with this, | |
797 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
798 | * blocking SIG were ruled out because they are not running and already | |
799 | * have pending signals. Such threads will dequeue from the shared queue | |
800 | * as soon as they're available, so putting the signal on the shared queue | |
801 | * will be equivalent to sending it to one such thread. | |
802 | */ | |
803 | static inline int wants_signal(int sig, struct task_struct *p) | |
804 | { | |
805 | if (sigismember(&p->blocked, sig)) | |
806 | return 0; | |
807 | if (p->flags & PF_EXITING) | |
808 | return 0; | |
809 | if (sig == SIGKILL) | |
810 | return 1; | |
811 | if (task_is_stopped_or_traced(p)) | |
812 | return 0; | |
813 | return task_curr(p) || !signal_pending(p); | |
814 | } | |
815 | ||
5fcd835b | 816 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
817 | { |
818 | struct signal_struct *signal = p->signal; | |
819 | struct task_struct *t; | |
820 | ||
821 | /* | |
822 | * Now find a thread we can wake up to take the signal off the queue. | |
823 | * | |
824 | * If the main thread wants the signal, it gets first crack. | |
825 | * Probably the least surprising to the average bear. | |
826 | */ | |
827 | if (wants_signal(sig, p)) | |
828 | t = p; | |
5fcd835b | 829 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
830 | /* |
831 | * There is just one thread and it does not need to be woken. | |
832 | * It will dequeue unblocked signals before it runs again. | |
833 | */ | |
834 | return; | |
835 | else { | |
836 | /* | |
837 | * Otherwise try to find a suitable thread. | |
838 | */ | |
839 | t = signal->curr_target; | |
840 | while (!wants_signal(sig, t)) { | |
841 | t = next_thread(t); | |
842 | if (t == signal->curr_target) | |
843 | /* | |
844 | * No thread needs to be woken. | |
845 | * Any eligible threads will see | |
846 | * the signal in the queue soon. | |
847 | */ | |
848 | return; | |
849 | } | |
850 | signal->curr_target = t; | |
851 | } | |
852 | ||
853 | /* | |
854 | * Found a killable thread. If the signal will be fatal, | |
855 | * then start taking the whole group down immediately. | |
856 | */ | |
fae5fa44 ON |
857 | if (sig_fatal(p, sig) && |
858 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 859 | !sigismember(&t->real_blocked, sig) && |
445a91d2 | 860 | (sig == SIGKILL || |
43918f2b | 861 | !tracehook_consider_fatal_signal(t, sig))) { |
71f11dc0 ON |
862 | /* |
863 | * This signal will be fatal to the whole group. | |
864 | */ | |
865 | if (!sig_kernel_coredump(sig)) { | |
866 | /* | |
867 | * Start a group exit and wake everybody up. | |
868 | * This way we don't have other threads | |
869 | * running and doing things after a slower | |
870 | * thread has the fatal signal pending. | |
871 | */ | |
872 | signal->flags = SIGNAL_GROUP_EXIT; | |
873 | signal->group_exit_code = sig; | |
874 | signal->group_stop_count = 0; | |
875 | t = p; | |
876 | do { | |
877 | sigaddset(&t->pending.signal, SIGKILL); | |
878 | signal_wake_up(t, 1); | |
879 | } while_each_thread(p, t); | |
880 | return; | |
881 | } | |
882 | } | |
883 | ||
884 | /* | |
885 | * The signal is already in the shared-pending queue. | |
886 | * Tell the chosen thread to wake up and dequeue it. | |
887 | */ | |
888 | signal_wake_up(t, sig == SIGKILL); | |
889 | return; | |
890 | } | |
891 | ||
af7fff9c PE |
892 | static inline int legacy_queue(struct sigpending *signals, int sig) |
893 | { | |
894 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
895 | } | |
896 | ||
7978b567 SB |
897 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
898 | int group, int from_ancestor_ns) | |
1da177e4 | 899 | { |
2ca3515a | 900 | struct sigpending *pending; |
6e65acba | 901 | struct sigqueue *q; |
7a0aeb14 | 902 | int override_rlimit; |
1da177e4 | 903 | |
d1eb650f | 904 | trace_signal_generate(sig, info, t); |
0a16b607 | 905 | |
6e65acba | 906 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 SB |
907 | |
908 | if (!prepare_signal(sig, t, from_ancestor_ns)) | |
7e695a5e | 909 | return 0; |
2ca3515a ON |
910 | |
911 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
912 | /* |
913 | * Short-circuit ignored signals and support queuing | |
914 | * exactly one non-rt signal, so that we can get more | |
915 | * detailed information about the cause of the signal. | |
916 | */ | |
7e695a5e | 917 | if (legacy_queue(pending, sig)) |
2acb024d | 918 | return 0; |
1da177e4 LT |
919 | /* |
920 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
921 | * or SIGKILL. | |
922 | */ | |
b67a1b9e | 923 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
924 | goto out_set; |
925 | ||
926 | /* Real-time signals must be queued if sent by sigqueue, or | |
927 | some other real-time mechanism. It is implementation | |
928 | defined whether kill() does so. We attempt to do so, on | |
929 | the principle of least surprise, but since kill is not | |
930 | allowed to fail with EAGAIN when low on memory we just | |
931 | make sure at least one signal gets delivered and don't | |
932 | pass on the info struct. */ | |
933 | ||
7a0aeb14 VN |
934 | if (sig < SIGRTMIN) |
935 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
936 | else | |
937 | override_rlimit = 0; | |
938 | ||
f84d49b2 | 939 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 940 | override_rlimit); |
1da177e4 | 941 | if (q) { |
2ca3515a | 942 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 943 | switch ((unsigned long) info) { |
b67a1b9e | 944 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
945 | q->info.si_signo = sig; |
946 | q->info.si_errno = 0; | |
947 | q->info.si_code = SI_USER; | |
9cd4fd10 | 948 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 949 | task_active_pid_ns(t)); |
76aac0e9 | 950 | q->info.si_uid = current_uid(); |
1da177e4 | 951 | break; |
b67a1b9e | 952 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
953 | q->info.si_signo = sig; |
954 | q->info.si_errno = 0; | |
955 | q->info.si_code = SI_KERNEL; | |
956 | q->info.si_pid = 0; | |
957 | q->info.si_uid = 0; | |
958 | break; | |
959 | default: | |
960 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
961 | if (from_ancestor_ns) |
962 | q->info.si_pid = 0; | |
1da177e4 LT |
963 | break; |
964 | } | |
621d3121 | 965 | } else if (!is_si_special(info)) { |
ba005e1f MH |
966 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
967 | /* | |
968 | * Queue overflow, abort. We may abort if the | |
969 | * signal was rt and sent by user using something | |
970 | * other than kill(). | |
971 | */ | |
972 | trace_signal_overflow_fail(sig, group, info); | |
1da177e4 | 973 | return -EAGAIN; |
ba005e1f MH |
974 | } else { |
975 | /* | |
976 | * This is a silent loss of information. We still | |
977 | * send the signal, but the *info bits are lost. | |
978 | */ | |
979 | trace_signal_lose_info(sig, group, info); | |
980 | } | |
1da177e4 LT |
981 | } |
982 | ||
983 | out_set: | |
53c30337 | 984 | signalfd_notify(t, sig); |
2ca3515a | 985 | sigaddset(&pending->signal, sig); |
4cd4b6d4 PE |
986 | complete_signal(sig, t, group); |
987 | return 0; | |
1da177e4 LT |
988 | } |
989 | ||
7978b567 SB |
990 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
991 | int group) | |
992 | { | |
921cf9f6 SB |
993 | int from_ancestor_ns = 0; |
994 | ||
995 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
996 | from_ancestor_ns = si_fromuser(info) && |
997 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
998 | #endif |
999 | ||
1000 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1001 | } |
1002 | ||
45807a1d IM |
1003 | static void print_fatal_signal(struct pt_regs *regs, int signr) |
1004 | { | |
1005 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 1006 | current->comm, task_pid_nr(current), signr); |
45807a1d | 1007 | |
ca5cd877 | 1008 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 1009 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
1010 | { |
1011 | int i; | |
1012 | for (i = 0; i < 16; i++) { | |
1013 | unsigned char insn; | |
1014 | ||
b45c6e76 AK |
1015 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1016 | break; | |
45807a1d IM |
1017 | printk("%02x ", insn); |
1018 | } | |
1019 | } | |
1020 | #endif | |
1021 | printk("\n"); | |
3a9f84d3 | 1022 | preempt_disable(); |
45807a1d | 1023 | show_regs(regs); |
3a9f84d3 | 1024 | preempt_enable(); |
45807a1d IM |
1025 | } |
1026 | ||
1027 | static int __init setup_print_fatal_signals(char *str) | |
1028 | { | |
1029 | get_option (&str, &print_fatal_signals); | |
1030 | ||
1031 | return 1; | |
1032 | } | |
1033 | ||
1034 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1035 | |
4cd4b6d4 PE |
1036 | int |
1037 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1038 | { | |
1039 | return send_signal(sig, info, p, 1); | |
1040 | } | |
1041 | ||
1da177e4 LT |
1042 | static int |
1043 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1044 | { | |
4cd4b6d4 | 1045 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1046 | } |
1047 | ||
4a30debf ON |
1048 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1049 | bool group) | |
1050 | { | |
1051 | unsigned long flags; | |
1052 | int ret = -ESRCH; | |
1053 | ||
1054 | if (lock_task_sighand(p, &flags)) { | |
1055 | ret = send_signal(sig, info, p, group); | |
1056 | unlock_task_sighand(p, &flags); | |
1057 | } | |
1058 | ||
1059 | return ret; | |
1060 | } | |
1061 | ||
1da177e4 LT |
1062 | /* |
1063 | * Force a signal that the process can't ignore: if necessary | |
1064 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1065 | * |
1066 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1067 | * since we do not want to have a signal handler that was blocked | |
1068 | * be invoked when user space had explicitly blocked it. | |
1069 | * | |
80fe728d ON |
1070 | * We don't want to have recursive SIGSEGV's etc, for example, |
1071 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1072 | */ |
1da177e4 LT |
1073 | int |
1074 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1075 | { | |
1076 | unsigned long int flags; | |
ae74c3b6 LT |
1077 | int ret, blocked, ignored; |
1078 | struct k_sigaction *action; | |
1da177e4 LT |
1079 | |
1080 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1081 | action = &t->sighand->action[sig-1]; |
1082 | ignored = action->sa.sa_handler == SIG_IGN; | |
1083 | blocked = sigismember(&t->blocked, sig); | |
1084 | if (blocked || ignored) { | |
1085 | action->sa.sa_handler = SIG_DFL; | |
1086 | if (blocked) { | |
1087 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1088 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1089 | } |
1da177e4 | 1090 | } |
80fe728d ON |
1091 | if (action->sa.sa_handler == SIG_DFL) |
1092 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1093 | ret = specific_send_sig_info(sig, info, t); |
1094 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1095 | ||
1096 | return ret; | |
1097 | } | |
1098 | ||
1da177e4 LT |
1099 | /* |
1100 | * Nuke all other threads in the group. | |
1101 | */ | |
09faef11 | 1102 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1103 | { |
09faef11 ON |
1104 | struct task_struct *t = p; |
1105 | int count = 0; | |
1da177e4 | 1106 | |
1da177e4 LT |
1107 | p->signal->group_stop_count = 0; |
1108 | ||
09faef11 ON |
1109 | while_each_thread(p, t) { |
1110 | count++; | |
1111 | ||
1112 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1113 | if (t->exit_state) |
1114 | continue; | |
1da177e4 | 1115 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1116 | signal_wake_up(t, 1); |
1117 | } | |
09faef11 ON |
1118 | |
1119 | return count; | |
1da177e4 LT |
1120 | } |
1121 | ||
b8ed374e NK |
1122 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1123 | unsigned long *flags) | |
f63ee72e ON |
1124 | { |
1125 | struct sighand_struct *sighand; | |
1126 | ||
1406f2d3 | 1127 | rcu_read_lock(); |
f63ee72e ON |
1128 | for (;;) { |
1129 | sighand = rcu_dereference(tsk->sighand); | |
1130 | if (unlikely(sighand == NULL)) | |
1131 | break; | |
1132 | ||
1133 | spin_lock_irqsave(&sighand->siglock, *flags); | |
1134 | if (likely(sighand == tsk->sighand)) | |
1135 | break; | |
1136 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
1137 | } | |
1406f2d3 | 1138 | rcu_read_unlock(); |
f63ee72e ON |
1139 | |
1140 | return sighand; | |
1141 | } | |
1142 | ||
c69e8d9c DH |
1143 | /* |
1144 | * send signal info to all the members of a group | |
c69e8d9c | 1145 | */ |
1da177e4 LT |
1146 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1147 | { | |
694f690d DH |
1148 | int ret; |
1149 | ||
1150 | rcu_read_lock(); | |
1151 | ret = check_kill_permission(sig, info, p); | |
1152 | rcu_read_unlock(); | |
f63ee72e | 1153 | |
4a30debf ON |
1154 | if (!ret && sig) |
1155 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1156 | |
1157 | return ret; | |
1158 | } | |
1159 | ||
1160 | /* | |
146a505d | 1161 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1162 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1163 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1164 | */ |
c4b92fc1 | 1165 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1166 | { |
1167 | struct task_struct *p = NULL; | |
1168 | int retval, success; | |
1169 | ||
1da177e4 LT |
1170 | success = 0; |
1171 | retval = -ESRCH; | |
c4b92fc1 | 1172 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1173 | int err = group_send_sig_info(sig, info, p); |
1174 | success |= !err; | |
1175 | retval = err; | |
c4b92fc1 | 1176 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1177 | return success ? 0 : retval; |
1178 | } | |
1179 | ||
c4b92fc1 | 1180 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1181 | { |
d36174bc | 1182 | int error = -ESRCH; |
1da177e4 LT |
1183 | struct task_struct *p; |
1184 | ||
e56d0903 | 1185 | rcu_read_lock(); |
d36174bc | 1186 | retry: |
c4b92fc1 | 1187 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1188 | if (p) { |
1da177e4 | 1189 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1190 | if (unlikely(error == -ESRCH)) |
1191 | /* | |
1192 | * The task was unhashed in between, try again. | |
1193 | * If it is dead, pid_task() will return NULL, | |
1194 | * if we race with de_thread() it will find the | |
1195 | * new leader. | |
1196 | */ | |
1197 | goto retry; | |
1198 | } | |
e56d0903 | 1199 | rcu_read_unlock(); |
6ca25b55 | 1200 | |
1da177e4 LT |
1201 | return error; |
1202 | } | |
1203 | ||
c3de4b38 MW |
1204 | int |
1205 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
c4b92fc1 EB |
1206 | { |
1207 | int error; | |
1208 | rcu_read_lock(); | |
b488893a | 1209 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1210 | rcu_read_unlock(); |
1211 | return error; | |
1212 | } | |
1213 | ||
2425c08b EB |
1214 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1215 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1216 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1217 | { |
1218 | int ret = -EINVAL; | |
1219 | struct task_struct *p; | |
c69e8d9c | 1220 | const struct cred *pcred; |
14d8c9f3 | 1221 | unsigned long flags; |
46113830 HW |
1222 | |
1223 | if (!valid_signal(sig)) | |
1224 | return ret; | |
1225 | ||
14d8c9f3 | 1226 | rcu_read_lock(); |
2425c08b | 1227 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1228 | if (!p) { |
1229 | ret = -ESRCH; | |
1230 | goto out_unlock; | |
1231 | } | |
c69e8d9c | 1232 | pcred = __task_cred(p); |
614c517d | 1233 | if (si_fromuser(info) && |
c69e8d9c DH |
1234 | euid != pcred->suid && euid != pcred->uid && |
1235 | uid != pcred->suid && uid != pcred->uid) { | |
46113830 HW |
1236 | ret = -EPERM; |
1237 | goto out_unlock; | |
1238 | } | |
8f95dc58 DQ |
1239 | ret = security_task_kill(p, info, sig, secid); |
1240 | if (ret) | |
1241 | goto out_unlock; | |
14d8c9f3 TG |
1242 | |
1243 | if (sig) { | |
1244 | if (lock_task_sighand(p, &flags)) { | |
1245 | ret = __send_signal(sig, info, p, 1, 0); | |
1246 | unlock_task_sighand(p, &flags); | |
1247 | } else | |
1248 | ret = -ESRCH; | |
46113830 HW |
1249 | } |
1250 | out_unlock: | |
14d8c9f3 | 1251 | rcu_read_unlock(); |
46113830 HW |
1252 | return ret; |
1253 | } | |
2425c08b | 1254 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1255 | |
1256 | /* | |
1257 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1258 | * | |
1259 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1260 | * is probably wrong. Should make it like BSD or SYSV. | |
1261 | */ | |
1262 | ||
bc64efd2 | 1263 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1264 | { |
8d42db18 | 1265 | int ret; |
d5df763b PE |
1266 | |
1267 | if (pid > 0) { | |
1268 | rcu_read_lock(); | |
1269 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1270 | rcu_read_unlock(); | |
1271 | return ret; | |
1272 | } | |
1273 | ||
1274 | read_lock(&tasklist_lock); | |
1275 | if (pid != -1) { | |
1276 | ret = __kill_pgrp_info(sig, info, | |
1277 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1278 | } else { | |
1da177e4 LT |
1279 | int retval = 0, count = 0; |
1280 | struct task_struct * p; | |
1281 | ||
1da177e4 | 1282 | for_each_process(p) { |
d25141a8 SB |
1283 | if (task_pid_vnr(p) > 1 && |
1284 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1285 | int err = group_send_sig_info(sig, info, p); |
1286 | ++count; | |
1287 | if (err != -EPERM) | |
1288 | retval = err; | |
1289 | } | |
1290 | } | |
8d42db18 | 1291 | ret = count ? retval : -ESRCH; |
1da177e4 | 1292 | } |
d5df763b PE |
1293 | read_unlock(&tasklist_lock); |
1294 | ||
8d42db18 | 1295 | return ret; |
1da177e4 LT |
1296 | } |
1297 | ||
1298 | /* | |
1299 | * These are for backward compatibility with the rest of the kernel source. | |
1300 | */ | |
1301 | ||
1da177e4 LT |
1302 | int |
1303 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1304 | { | |
1da177e4 LT |
1305 | /* |
1306 | * Make sure legacy kernel users don't send in bad values | |
1307 | * (normal paths check this in check_kill_permission). | |
1308 | */ | |
7ed20e1a | 1309 | if (!valid_signal(sig)) |
1da177e4 LT |
1310 | return -EINVAL; |
1311 | ||
4a30debf | 1312 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1313 | } |
1314 | ||
b67a1b9e ON |
1315 | #define __si_special(priv) \ |
1316 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1317 | ||
1da177e4 LT |
1318 | int |
1319 | send_sig(int sig, struct task_struct *p, int priv) | |
1320 | { | |
b67a1b9e | 1321 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1322 | } |
1323 | ||
1da177e4 LT |
1324 | void |
1325 | force_sig(int sig, struct task_struct *p) | |
1326 | { | |
b67a1b9e | 1327 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1328 | } |
1329 | ||
1330 | /* | |
1331 | * When things go south during signal handling, we | |
1332 | * will force a SIGSEGV. And if the signal that caused | |
1333 | * the problem was already a SIGSEGV, we'll want to | |
1334 | * make sure we don't even try to deliver the signal.. | |
1335 | */ | |
1336 | int | |
1337 | force_sigsegv(int sig, struct task_struct *p) | |
1338 | { | |
1339 | if (sig == SIGSEGV) { | |
1340 | unsigned long flags; | |
1341 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1342 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1343 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1344 | } | |
1345 | force_sig(SIGSEGV, p); | |
1346 | return 0; | |
1347 | } | |
1348 | ||
c4b92fc1 EB |
1349 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1350 | { | |
146a505d PE |
1351 | int ret; |
1352 | ||
1353 | read_lock(&tasklist_lock); | |
1354 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1355 | read_unlock(&tasklist_lock); | |
1356 | ||
1357 | return ret; | |
c4b92fc1 EB |
1358 | } |
1359 | EXPORT_SYMBOL(kill_pgrp); | |
1360 | ||
1361 | int kill_pid(struct pid *pid, int sig, int priv) | |
1362 | { | |
1363 | return kill_pid_info(sig, __si_special(priv), pid); | |
1364 | } | |
1365 | EXPORT_SYMBOL(kill_pid); | |
1366 | ||
1da177e4 LT |
1367 | /* |
1368 | * These functions support sending signals using preallocated sigqueue | |
1369 | * structures. This is needed "because realtime applications cannot | |
1370 | * afford to lose notifications of asynchronous events, like timer | |
f84d49b2 | 1371 | * expirations or I/O completions". In the case of Posix Timers |
1da177e4 LT |
1372 | * we allocate the sigqueue structure from the timer_create. If this |
1373 | * allocation fails we are able to report the failure to the application | |
1374 | * with an EAGAIN error. | |
1375 | */ | |
1da177e4 LT |
1376 | struct sigqueue *sigqueue_alloc(void) |
1377 | { | |
f84d49b2 | 1378 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1379 | |
f84d49b2 | 1380 | if (q) |
1da177e4 | 1381 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1382 | |
1383 | return q; | |
1da177e4 LT |
1384 | } |
1385 | ||
1386 | void sigqueue_free(struct sigqueue *q) | |
1387 | { | |
1388 | unsigned long flags; | |
60187d27 ON |
1389 | spinlock_t *lock = ¤t->sighand->siglock; |
1390 | ||
1da177e4 LT |
1391 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1392 | /* | |
c8e85b4f ON |
1393 | * We must hold ->siglock while testing q->list |
1394 | * to serialize with collect_signal() or with | |
da7978b0 | 1395 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1396 | */ |
60187d27 | 1397 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1398 | q->flags &= ~SIGQUEUE_PREALLOC; |
1399 | /* | |
1400 | * If it is queued it will be freed when dequeued, | |
1401 | * like the "regular" sigqueue. | |
1402 | */ | |
60187d27 | 1403 | if (!list_empty(&q->list)) |
c8e85b4f | 1404 | q = NULL; |
60187d27 ON |
1405 | spin_unlock_irqrestore(lock, flags); |
1406 | ||
c8e85b4f ON |
1407 | if (q) |
1408 | __sigqueue_free(q); | |
1da177e4 LT |
1409 | } |
1410 | ||
ac5c2153 | 1411 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1412 | { |
e62e6650 | 1413 | int sig = q->info.si_signo; |
2ca3515a | 1414 | struct sigpending *pending; |
e62e6650 ON |
1415 | unsigned long flags; |
1416 | int ret; | |
2ca3515a | 1417 | |
4cd4b6d4 | 1418 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1419 | |
1420 | ret = -1; | |
1421 | if (!likely(lock_task_sighand(t, &flags))) | |
1422 | goto ret; | |
1423 | ||
7e695a5e | 1424 | ret = 1; /* the signal is ignored */ |
921cf9f6 | 1425 | if (!prepare_signal(sig, t, 0)) |
e62e6650 ON |
1426 | goto out; |
1427 | ||
1428 | ret = 0; | |
9e3bd6c3 PE |
1429 | if (unlikely(!list_empty(&q->list))) { |
1430 | /* | |
1431 | * If an SI_TIMER entry is already queue just increment | |
1432 | * the overrun count. | |
1433 | */ | |
9e3bd6c3 PE |
1434 | BUG_ON(q->info.si_code != SI_TIMER); |
1435 | q->info.si_overrun++; | |
e62e6650 | 1436 | goto out; |
9e3bd6c3 | 1437 | } |
ba661292 | 1438 | q->info.si_overrun = 0; |
9e3bd6c3 | 1439 | |
9e3bd6c3 | 1440 | signalfd_notify(t, sig); |
2ca3515a | 1441 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1442 | list_add_tail(&q->list, &pending->list); |
1443 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1444 | complete_signal(sig, t, group); |
e62e6650 ON |
1445 | out: |
1446 | unlock_task_sighand(t, &flags); | |
1447 | ret: | |
1448 | return ret; | |
9e3bd6c3 PE |
1449 | } |
1450 | ||
1da177e4 LT |
1451 | /* |
1452 | * Let a parent know about the death of a child. | |
1453 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 RM |
1454 | * |
1455 | * Returns -1 if our parent ignored us and so we've switched to | |
1456 | * self-reaping, or else @sig. | |
1da177e4 | 1457 | */ |
2b2a1ff6 | 1458 | int do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1459 | { |
1460 | struct siginfo info; | |
1461 | unsigned long flags; | |
1462 | struct sighand_struct *psig; | |
1b04624f | 1463 | int ret = sig; |
1da177e4 LT |
1464 | |
1465 | BUG_ON(sig == -1); | |
1466 | ||
1467 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1468 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1469 | |
5cb11446 | 1470 | BUG_ON(!task_ptrace(tsk) && |
1da177e4 LT |
1471 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1472 | ||
1473 | info.si_signo = sig; | |
1474 | info.si_errno = 0; | |
b488893a PE |
1475 | /* |
1476 | * we are under tasklist_lock here so our parent is tied to | |
1477 | * us and cannot exit and release its namespace. | |
1478 | * | |
1479 | * the only it can is to switch its nsproxy with sys_unshare, | |
1480 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1481 | * see relevant namespace | |
1482 | * | |
1483 | * write_lock() currently calls preempt_disable() which is the | |
1484 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1485 | * correct to rely on this | |
1486 | */ | |
1487 | rcu_read_lock(); | |
1488 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
c69e8d9c | 1489 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1490 | rcu_read_unlock(); |
1491 | ||
32bd671d PZ |
1492 | info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime, |
1493 | tsk->signal->utime)); | |
1494 | info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime, | |
1495 | tsk->signal->stime)); | |
1da177e4 LT |
1496 | |
1497 | info.si_status = tsk->exit_code & 0x7f; | |
1498 | if (tsk->exit_code & 0x80) | |
1499 | info.si_code = CLD_DUMPED; | |
1500 | else if (tsk->exit_code & 0x7f) | |
1501 | info.si_code = CLD_KILLED; | |
1502 | else { | |
1503 | info.si_code = CLD_EXITED; | |
1504 | info.si_status = tsk->exit_code >> 8; | |
1505 | } | |
1506 | ||
1507 | psig = tsk->parent->sighand; | |
1508 | spin_lock_irqsave(&psig->siglock, flags); | |
5cb11446 | 1509 | if (!task_ptrace(tsk) && sig == SIGCHLD && |
1da177e4 LT |
1510 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1511 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1512 | /* | |
1513 | * We are exiting and our parent doesn't care. POSIX.1 | |
1514 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1515 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1516 | * automatically and not left for our parent's wait4 call. | |
1517 | * Rather than having the parent do it as a magic kind of | |
1518 | * signal handler, we just set this to tell do_exit that we | |
1519 | * can be cleaned up without becoming a zombie. Note that | |
1520 | * we still call __wake_up_parent in this case, because a | |
1521 | * blocked sys_wait4 might now return -ECHILD. | |
1522 | * | |
1523 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1524 | * is implementation-defined: we do (if you don't want | |
1525 | * it, just use SIG_IGN instead). | |
1526 | */ | |
1b04624f | 1527 | ret = tsk->exit_signal = -1; |
1da177e4 | 1528 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
2b2a1ff6 | 1529 | sig = -1; |
1da177e4 | 1530 | } |
7ed20e1a | 1531 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1532 | __group_send_sig_info(sig, &info, tsk->parent); |
1533 | __wake_up_parent(tsk, tsk->parent); | |
1534 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1535 | |
1b04624f | 1536 | return ret; |
1da177e4 LT |
1537 | } |
1538 | ||
a1d5e21e | 1539 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why) |
1da177e4 LT |
1540 | { |
1541 | struct siginfo info; | |
1542 | unsigned long flags; | |
bc505a47 | 1543 | struct task_struct *parent; |
1da177e4 LT |
1544 | struct sighand_struct *sighand; |
1545 | ||
5cb11446 | 1546 | if (task_ptrace(tsk)) |
bc505a47 ON |
1547 | parent = tsk->parent; |
1548 | else { | |
1549 | tsk = tsk->group_leader; | |
1550 | parent = tsk->real_parent; | |
1551 | } | |
1552 | ||
1da177e4 LT |
1553 | info.si_signo = SIGCHLD; |
1554 | info.si_errno = 0; | |
b488893a PE |
1555 | /* |
1556 | * see comment in do_notify_parent() abot the following 3 lines | |
1557 | */ | |
1558 | rcu_read_lock(); | |
d9265663 | 1559 | info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns); |
c69e8d9c | 1560 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1561 | rcu_read_unlock(); |
1562 | ||
d8878ba3 MK |
1563 | info.si_utime = cputime_to_clock_t(tsk->utime); |
1564 | info.si_stime = cputime_to_clock_t(tsk->stime); | |
1da177e4 LT |
1565 | |
1566 | info.si_code = why; | |
1567 | switch (why) { | |
1568 | case CLD_CONTINUED: | |
1569 | info.si_status = SIGCONT; | |
1570 | break; | |
1571 | case CLD_STOPPED: | |
1572 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1573 | break; | |
1574 | case CLD_TRAPPED: | |
1575 | info.si_status = tsk->exit_code & 0x7f; | |
1576 | break; | |
1577 | default: | |
1578 | BUG(); | |
1579 | } | |
1580 | ||
1581 | sighand = parent->sighand; | |
1582 | spin_lock_irqsave(&sighand->siglock, flags); | |
1583 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1584 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1585 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1586 | /* | |
1587 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1588 | */ | |
1589 | __wake_up_parent(tsk, parent); | |
1590 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1591 | } | |
1592 | ||
d5f70c00 ON |
1593 | static inline int may_ptrace_stop(void) |
1594 | { | |
5cb11446 | 1595 | if (!likely(task_ptrace(current))) |
d5f70c00 | 1596 | return 0; |
d5f70c00 ON |
1597 | /* |
1598 | * Are we in the middle of do_coredump? | |
1599 | * If so and our tracer is also part of the coredump stopping | |
1600 | * is a deadlock situation, and pointless because our tracer | |
1601 | * is dead so don't allow us to stop. | |
1602 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1603 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 ON |
1604 | * is safe to enter schedule(). |
1605 | */ | |
999d9fc1 | 1606 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1607 | unlikely(current->mm == current->parent->mm)) |
1608 | return 0; | |
1609 | ||
1610 | return 1; | |
1611 | } | |
1612 | ||
1a669c2f RM |
1613 | /* |
1614 | * Return nonzero if there is a SIGKILL that should be waking us up. | |
1615 | * Called with the siglock held. | |
1616 | */ | |
1617 | static int sigkill_pending(struct task_struct *tsk) | |
1618 | { | |
3d749b9e ON |
1619 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1620 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1621 | } |
1622 | ||
1da177e4 LT |
1623 | /* |
1624 | * This must be called with current->sighand->siglock held. | |
1625 | * | |
1626 | * This should be the path for all ptrace stops. | |
1627 | * We always set current->last_siginfo while stopped here. | |
1628 | * That makes it a way to test a stopped process for | |
1629 | * being ptrace-stopped vs being job-control-stopped. | |
1630 | * | |
20686a30 ON |
1631 | * If we actually decide not to stop at all because the tracer |
1632 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1633 | */ |
20686a30 | 1634 | static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) |
b8401150 NK |
1635 | __releases(¤t->sighand->siglock) |
1636 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1637 | { |
1a669c2f RM |
1638 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1639 | /* | |
1640 | * The arch code has something special to do before a | |
1641 | * ptrace stop. This is allowed to block, e.g. for faults | |
1642 | * on user stack pages. We can't keep the siglock while | |
1643 | * calling arch_ptrace_stop, so we must release it now. | |
1644 | * To preserve proper semantics, we must do this before | |
1645 | * any signal bookkeeping like checking group_stop_count. | |
1646 | * Meanwhile, a SIGKILL could come in before we retake the | |
1647 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1648 | * So after regaining the lock, we must check for SIGKILL. | |
1649 | */ | |
1650 | spin_unlock_irq(¤t->sighand->siglock); | |
1651 | arch_ptrace_stop(exit_code, info); | |
1652 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1653 | if (sigkill_pending(current)) |
1654 | return; | |
1a669c2f RM |
1655 | } |
1656 | ||
1da177e4 LT |
1657 | /* |
1658 | * If there is a group stop in progress, | |
1659 | * we must participate in the bookkeeping. | |
1660 | */ | |
1661 | if (current->signal->group_stop_count > 0) | |
1662 | --current->signal->group_stop_count; | |
1663 | ||
1664 | current->last_siginfo = info; | |
1665 | current->exit_code = exit_code; | |
1666 | ||
1667 | /* Let the debugger run. */ | |
d9ae90ac | 1668 | __set_current_state(TASK_TRACED); |
1da177e4 LT |
1669 | spin_unlock_irq(¤t->sighand->siglock); |
1670 | read_lock(&tasklist_lock); | |
3d749b9e | 1671 | if (may_ptrace_stop()) { |
a1d5e21e | 1672 | do_notify_parent_cldstop(current, CLD_TRAPPED); |
53da1d94 MS |
1673 | /* |
1674 | * Don't want to allow preemption here, because | |
1675 | * sys_ptrace() needs this task to be inactive. | |
1676 | * | |
1677 | * XXX: implement read_unlock_no_resched(). | |
1678 | */ | |
1679 | preempt_disable(); | |
1da177e4 | 1680 | read_unlock(&tasklist_lock); |
53da1d94 | 1681 | preempt_enable_no_resched(); |
1da177e4 LT |
1682 | schedule(); |
1683 | } else { | |
1684 | /* | |
1685 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1686 | * Don't drop the lock yet, another tracer may come. |
1da177e4 | 1687 | */ |
6405f7f4 | 1688 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1689 | if (clear_code) |
1690 | current->exit_code = 0; | |
6405f7f4 | 1691 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1692 | } |
1693 | ||
13b1c3d4 RM |
1694 | /* |
1695 | * While in TASK_TRACED, we were considered "frozen enough". | |
1696 | * Now that we woke up, it's crucial if we're supposed to be | |
1697 | * frozen that we freeze now before running anything substantial. | |
1698 | */ | |
1699 | try_to_freeze(); | |
1700 | ||
1da177e4 LT |
1701 | /* |
1702 | * We are back. Now reacquire the siglock before touching | |
1703 | * last_siginfo, so that we are sure to have synchronized with | |
1704 | * any signal-sending on another CPU that wants to examine it. | |
1705 | */ | |
1706 | spin_lock_irq(¤t->sighand->siglock); | |
1707 | current->last_siginfo = NULL; | |
1708 | ||
1709 | /* | |
1710 | * Queued signals ignored us while we were stopped for tracing. | |
1711 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1712 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1713 | */ |
b74d0deb | 1714 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1715 | } |
1716 | ||
1717 | void ptrace_notify(int exit_code) | |
1718 | { | |
1719 | siginfo_t info; | |
1720 | ||
1721 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1722 | ||
1723 | memset(&info, 0, sizeof info); | |
1724 | info.si_signo = SIGTRAP; | |
1725 | info.si_code = exit_code; | |
b488893a | 1726 | info.si_pid = task_pid_vnr(current); |
76aac0e9 | 1727 | info.si_uid = current_uid(); |
1da177e4 LT |
1728 | |
1729 | /* Let the debugger run. */ | |
1730 | spin_lock_irq(¤t->sighand->siglock); | |
20686a30 | 1731 | ptrace_stop(exit_code, 1, &info); |
1da177e4 LT |
1732 | spin_unlock_irq(¤t->sighand->siglock); |
1733 | } | |
1734 | ||
1da177e4 LT |
1735 | /* |
1736 | * This performs the stopping for SIGSTOP and other stop signals. | |
1737 | * We have to stop all threads in the thread group. | |
1738 | * Returns nonzero if we've actually stopped and released the siglock. | |
1739 | * Returns zero if we didn't stop and still hold the siglock. | |
1740 | */ | |
a122b341 | 1741 | static int do_signal_stop(int signr) |
1da177e4 LT |
1742 | { |
1743 | struct signal_struct *sig = current->signal; | |
ae6d2ed7 | 1744 | int notify; |
1da177e4 | 1745 | |
ae6d2ed7 | 1746 | if (!sig->group_stop_count) { |
f558b7e4 ON |
1747 | struct task_struct *t; |
1748 | ||
2b201a9e | 1749 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) || |
573cf9ad | 1750 | unlikely(signal_group_exit(sig))) |
f558b7e4 | 1751 | return 0; |
1da177e4 LT |
1752 | /* |
1753 | * There is no group stop already in progress. | |
a122b341 | 1754 | * We must initiate one now. |
1da177e4 | 1755 | */ |
a122b341 | 1756 | sig->group_exit_code = signr; |
1da177e4 | 1757 | |
ae6d2ed7 | 1758 | sig->group_stop_count = 1; |
a122b341 | 1759 | for (t = next_thread(current); t != current; t = next_thread(t)) |
1da177e4 | 1760 | /* |
a122b341 ON |
1761 | * Setting state to TASK_STOPPED for a group |
1762 | * stop is always done with the siglock held, | |
1763 | * so this check has no races. | |
1da177e4 | 1764 | */ |
d12619b5 | 1765 | if (!(t->flags & PF_EXITING) && |
e1abb39c | 1766 | !task_is_stopped_or_traced(t)) { |
ae6d2ed7 | 1767 | sig->group_stop_count++; |
a122b341 ON |
1768 | signal_wake_up(t, 0); |
1769 | } | |
1da177e4 | 1770 | } |
ae6d2ed7 RM |
1771 | /* |
1772 | * If there are no other threads in the group, or if there is | |
1773 | * a group stop in progress and we are the last to stop, report | |
1774 | * to the parent. When ptraced, every thread reports itself. | |
1775 | */ | |
1776 | notify = sig->group_stop_count == 1 ? CLD_STOPPED : 0; | |
1777 | notify = tracehook_notify_jctl(notify, CLD_STOPPED); | |
1778 | /* | |
1779 | * tracehook_notify_jctl() can drop and reacquire siglock, so | |
1780 | * we keep ->group_stop_count != 0 before the call. If SIGCONT | |
1781 | * or SIGKILL comes in between ->group_stop_count == 0. | |
1782 | */ | |
1783 | if (sig->group_stop_count) { | |
1784 | if (!--sig->group_stop_count) | |
1785 | sig->flags = SIGNAL_STOP_STOPPED; | |
1786 | current->exit_code = sig->group_exit_code; | |
1787 | __set_current_state(TASK_STOPPED); | |
1788 | } | |
1789 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 | 1790 | |
ae6d2ed7 RM |
1791 | if (notify) { |
1792 | read_lock(&tasklist_lock); | |
1793 | do_notify_parent_cldstop(current, notify); | |
1794 | read_unlock(&tasklist_lock); | |
1795 | } | |
1796 | ||
1797 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
1798 | do { | |
1799 | schedule(); | |
1800 | } while (try_to_freeze()); | |
1801 | ||
1802 | tracehook_finish_jctl(); | |
1803 | current->exit_code = 0; | |
dac27f4a | 1804 | |
1da177e4 LT |
1805 | return 1; |
1806 | } | |
1807 | ||
18c98b65 RM |
1808 | static int ptrace_signal(int signr, siginfo_t *info, |
1809 | struct pt_regs *regs, void *cookie) | |
1810 | { | |
5cb11446 | 1811 | if (!task_ptrace(current)) |
18c98b65 RM |
1812 | return signr; |
1813 | ||
1814 | ptrace_signal_deliver(regs, cookie); | |
1815 | ||
1816 | /* Let the debugger run. */ | |
1817 | ptrace_stop(signr, 0, info); | |
1818 | ||
1819 | /* We're back. Did the debugger cancel the sig? */ | |
1820 | signr = current->exit_code; | |
1821 | if (signr == 0) | |
1822 | return signr; | |
1823 | ||
1824 | current->exit_code = 0; | |
1825 | ||
1826 | /* Update the siginfo structure if the signal has | |
1827 | changed. If the debugger wanted something | |
1828 | specific in the siginfo structure then it should | |
1829 | have updated *info via PTRACE_SETSIGINFO. */ | |
1830 | if (signr != info->si_signo) { | |
1831 | info->si_signo = signr; | |
1832 | info->si_errno = 0; | |
1833 | info->si_code = SI_USER; | |
1834 | info->si_pid = task_pid_vnr(current->parent); | |
c69e8d9c | 1835 | info->si_uid = task_uid(current->parent); |
18c98b65 RM |
1836 | } |
1837 | ||
1838 | /* If the (new) signal is now blocked, requeue it. */ | |
1839 | if (sigismember(¤t->blocked, signr)) { | |
1840 | specific_send_sig_info(signr, info, current); | |
1841 | signr = 0; | |
1842 | } | |
1843 | ||
1844 | return signr; | |
1845 | } | |
1846 | ||
1da177e4 LT |
1847 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
1848 | struct pt_regs *regs, void *cookie) | |
1849 | { | |
f6b76d4f ON |
1850 | struct sighand_struct *sighand = current->sighand; |
1851 | struct signal_struct *signal = current->signal; | |
1852 | int signr; | |
1da177e4 | 1853 | |
13b1c3d4 RM |
1854 | relock: |
1855 | /* | |
1856 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
1857 | * While in TASK_STOPPED, we were considered "frozen enough". | |
1858 | * Now that we woke up, it's crucial if we're supposed to be | |
1859 | * frozen that we freeze now before running anything substantial. | |
1860 | */ | |
fc558a74 RW |
1861 | try_to_freeze(); |
1862 | ||
f6b76d4f | 1863 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
1864 | /* |
1865 | * Every stopped thread goes here after wakeup. Check to see if | |
1866 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
1867 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
1868 | */ | |
f6b76d4f ON |
1869 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
1870 | int why = (signal->flags & SIGNAL_STOP_CONTINUED) | |
e4420551 | 1871 | ? CLD_CONTINUED : CLD_STOPPED; |
f6b76d4f | 1872 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 1873 | |
ae6d2ed7 RM |
1874 | why = tracehook_notify_jctl(why, CLD_CONTINUED); |
1875 | spin_unlock_irq(&sighand->siglock); | |
fa00b80b | 1876 | |
ae6d2ed7 RM |
1877 | if (why) { |
1878 | read_lock(&tasklist_lock); | |
1879 | do_notify_parent_cldstop(current->group_leader, why); | |
1880 | read_unlock(&tasklist_lock); | |
1881 | } | |
e4420551 ON |
1882 | goto relock; |
1883 | } | |
1884 | ||
1da177e4 LT |
1885 | for (;;) { |
1886 | struct k_sigaction *ka; | |
7bcf6a2c RM |
1887 | /* |
1888 | * Tracing can induce an artifical signal and choose sigaction. | |
1889 | * The return value in @signr determines the default action, | |
1890 | * but @info->si_signo is the signal number we will report. | |
1891 | */ | |
1892 | signr = tracehook_get_signal(current, regs, info, return_ka); | |
1893 | if (unlikely(signr < 0)) | |
1894 | goto relock; | |
1895 | if (unlikely(signr != 0)) | |
1896 | ka = return_ka; | |
1897 | else { | |
1be53963 ON |
1898 | if (unlikely(signal->group_stop_count > 0) && |
1899 | do_signal_stop(0)) | |
1900 | goto relock; | |
1901 | ||
7bcf6a2c RM |
1902 | signr = dequeue_signal(current, ¤t->blocked, |
1903 | info); | |
1da177e4 | 1904 | |
18c98b65 | 1905 | if (!signr) |
7bcf6a2c RM |
1906 | break; /* will return 0 */ |
1907 | ||
1908 | if (signr != SIGKILL) { | |
1909 | signr = ptrace_signal(signr, info, | |
1910 | regs, cookie); | |
1911 | if (!signr) | |
1912 | continue; | |
1913 | } | |
1914 | ||
1915 | ka = &sighand->action[signr-1]; | |
1da177e4 LT |
1916 | } |
1917 | ||
f9d4257e MH |
1918 | /* Trace actually delivered signals. */ |
1919 | trace_signal_deliver(signr, info, ka); | |
1920 | ||
1da177e4 LT |
1921 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
1922 | continue; | |
1923 | if (ka->sa.sa_handler != SIG_DFL) { | |
1924 | /* Run the handler. */ | |
1925 | *return_ka = *ka; | |
1926 | ||
1927 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1928 | ka->sa.sa_handler = SIG_DFL; | |
1929 | ||
1930 | break; /* will return non-zero "signr" value */ | |
1931 | } | |
1932 | ||
1933 | /* | |
1934 | * Now we are doing the default action for this signal. | |
1935 | */ | |
1936 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1937 | continue; | |
1938 | ||
84d73786 | 1939 | /* |
0fbc26a6 | 1940 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
1941 | * Container-init gets no signals it doesn't want from same |
1942 | * container. | |
1943 | * | |
1944 | * Note that if global/container-init sees a sig_kernel_only() | |
1945 | * signal here, the signal must have been generated internally | |
1946 | * or must have come from an ancestor namespace. In either | |
1947 | * case, the signal cannot be dropped. | |
84d73786 | 1948 | */ |
fae5fa44 | 1949 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 1950 | !sig_kernel_only(signr)) |
1da177e4 LT |
1951 | continue; |
1952 | ||
1953 | if (sig_kernel_stop(signr)) { | |
1954 | /* | |
1955 | * The default action is to stop all threads in | |
1956 | * the thread group. The job control signals | |
1957 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1958 | * always works. Note that siglock needs to be | |
1959 | * dropped during the call to is_orphaned_pgrp() | |
1960 | * because of lock ordering with tasklist_lock. | |
1961 | * This allows an intervening SIGCONT to be posted. | |
1962 | * We need to check for that and bail out if necessary. | |
1963 | */ | |
1964 | if (signr != SIGSTOP) { | |
f6b76d4f | 1965 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1966 | |
1967 | /* signals can be posted during this window */ | |
1968 | ||
3e7cd6c4 | 1969 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
1970 | goto relock; |
1971 | ||
f6b76d4f | 1972 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
1973 | } |
1974 | ||
7bcf6a2c | 1975 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
1976 | /* It released the siglock. */ |
1977 | goto relock; | |
1978 | } | |
1979 | ||
1980 | /* | |
1981 | * We didn't actually stop, due to a race | |
1982 | * with SIGCONT or something like that. | |
1983 | */ | |
1984 | continue; | |
1985 | } | |
1986 | ||
f6b76d4f | 1987 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1988 | |
1989 | /* | |
1990 | * Anything else is fatal, maybe with a core dump. | |
1991 | */ | |
1992 | current->flags |= PF_SIGNALED; | |
2dce81bf | 1993 | |
1da177e4 | 1994 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 1995 | if (print_fatal_signals) |
7bcf6a2c | 1996 | print_fatal_signal(regs, info->si_signo); |
1da177e4 LT |
1997 | /* |
1998 | * If it was able to dump core, this kills all | |
1999 | * other threads in the group and synchronizes with | |
2000 | * their demise. If we lost the race with another | |
2001 | * thread getting here, it set group_exit_code | |
2002 | * first and our do_group_exit call below will use | |
2003 | * that value and ignore the one we pass it. | |
2004 | */ | |
7bcf6a2c | 2005 | do_coredump(info->si_signo, info->si_signo, regs); |
1da177e4 LT |
2006 | } |
2007 | ||
2008 | /* | |
2009 | * Death signals, no core dump. | |
2010 | */ | |
7bcf6a2c | 2011 | do_group_exit(info->si_signo); |
1da177e4 LT |
2012 | /* NOTREACHED */ |
2013 | } | |
f6b76d4f | 2014 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2015 | return signr; |
2016 | } | |
2017 | ||
d12619b5 ON |
2018 | void exit_signals(struct task_struct *tsk) |
2019 | { | |
2020 | int group_stop = 0; | |
5dee1707 | 2021 | struct task_struct *t; |
d12619b5 | 2022 | |
5dee1707 ON |
2023 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2024 | tsk->flags |= PF_EXITING; | |
2025 | return; | |
d12619b5 ON |
2026 | } |
2027 | ||
5dee1707 | 2028 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2029 | /* |
2030 | * From now this task is not visible for group-wide signals, | |
2031 | * see wants_signal(), do_signal_stop(). | |
2032 | */ | |
2033 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
2034 | if (!signal_pending(tsk)) |
2035 | goto out; | |
2036 | ||
2037 | /* It could be that __group_complete_signal() choose us to | |
2038 | * notify about group-wide signal. Another thread should be | |
2039 | * woken now to take the signal since we will not. | |
2040 | */ | |
2041 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
2042 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
2043 | recalc_sigpending_and_wake(t); | |
2044 | ||
2045 | if (unlikely(tsk->signal->group_stop_count) && | |
2046 | !--tsk->signal->group_stop_count) { | |
2047 | tsk->signal->flags = SIGNAL_STOP_STOPPED; | |
ae6d2ed7 | 2048 | group_stop = tracehook_notify_jctl(CLD_STOPPED, CLD_STOPPED); |
5dee1707 ON |
2049 | } |
2050 | out: | |
d12619b5 ON |
2051 | spin_unlock_irq(&tsk->sighand->siglock); |
2052 | ||
ae6d2ed7 | 2053 | if (unlikely(group_stop)) { |
d12619b5 | 2054 | read_lock(&tasklist_lock); |
ae6d2ed7 | 2055 | do_notify_parent_cldstop(tsk, group_stop); |
d12619b5 ON |
2056 | read_unlock(&tasklist_lock); |
2057 | } | |
2058 | } | |
2059 | ||
1da177e4 LT |
2060 | EXPORT_SYMBOL(recalc_sigpending); |
2061 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2062 | EXPORT_SYMBOL(flush_signals); | |
2063 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2064 | EXPORT_SYMBOL(send_sig); |
2065 | EXPORT_SYMBOL(send_sig_info); | |
2066 | EXPORT_SYMBOL(sigprocmask); | |
2067 | EXPORT_SYMBOL(block_all_signals); | |
2068 | EXPORT_SYMBOL(unblock_all_signals); | |
2069 | ||
2070 | ||
2071 | /* | |
2072 | * System call entry points. | |
2073 | */ | |
2074 | ||
754fe8d2 | 2075 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2076 | { |
2077 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2078 | return restart->fn(restart); | |
2079 | } | |
2080 | ||
2081 | long do_no_restart_syscall(struct restart_block *param) | |
2082 | { | |
2083 | return -EINTR; | |
2084 | } | |
2085 | ||
2086 | /* | |
2087 | * We don't need to get the kernel lock - this is all local to this | |
2088 | * particular thread.. (and that's good, because this is _heavily_ | |
2089 | * used by various programs) | |
2090 | */ | |
2091 | ||
2092 | /* | |
2093 | * This is also useful for kernel threads that want to temporarily | |
2094 | * (or permanently) block certain signals. | |
2095 | * | |
2096 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2097 | * interface happily blocks "unblockable" signals like SIGKILL | |
2098 | * and friends. | |
2099 | */ | |
2100 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2101 | { | |
2102 | int error; | |
1da177e4 LT |
2103 | |
2104 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
2105 | if (oldset) |
2106 | *oldset = current->blocked; | |
2107 | ||
1da177e4 LT |
2108 | error = 0; |
2109 | switch (how) { | |
2110 | case SIG_BLOCK: | |
2111 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2112 | break; | |
2113 | case SIG_UNBLOCK: | |
2114 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2115 | break; | |
2116 | case SIG_SETMASK: | |
2117 | current->blocked = *set; | |
2118 | break; | |
2119 | default: | |
2120 | error = -EINVAL; | |
2121 | } | |
2122 | recalc_sigpending(); | |
2123 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 2124 | |
1da177e4 LT |
2125 | return error; |
2126 | } | |
2127 | ||
17da2bd9 HC |
2128 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set, |
2129 | sigset_t __user *, oset, size_t, sigsetsize) | |
1da177e4 LT |
2130 | { |
2131 | int error = -EINVAL; | |
2132 | sigset_t old_set, new_set; | |
2133 | ||
2134 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2135 | if (sigsetsize != sizeof(sigset_t)) | |
2136 | goto out; | |
2137 | ||
2138 | if (set) { | |
2139 | error = -EFAULT; | |
2140 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2141 | goto out; | |
2142 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2143 | ||
2144 | error = sigprocmask(how, &new_set, &old_set); | |
2145 | if (error) | |
2146 | goto out; | |
2147 | if (oset) | |
2148 | goto set_old; | |
2149 | } else if (oset) { | |
2150 | spin_lock_irq(¤t->sighand->siglock); | |
2151 | old_set = current->blocked; | |
2152 | spin_unlock_irq(¤t->sighand->siglock); | |
2153 | ||
2154 | set_old: | |
2155 | error = -EFAULT; | |
2156 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2157 | goto out; | |
2158 | } | |
2159 | error = 0; | |
2160 | out: | |
2161 | return error; | |
2162 | } | |
2163 | ||
2164 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2165 | { | |
2166 | long error = -EINVAL; | |
2167 | sigset_t pending; | |
2168 | ||
2169 | if (sigsetsize > sizeof(sigset_t)) | |
2170 | goto out; | |
2171 | ||
2172 | spin_lock_irq(¤t->sighand->siglock); | |
2173 | sigorsets(&pending, ¤t->pending.signal, | |
2174 | ¤t->signal->shared_pending.signal); | |
2175 | spin_unlock_irq(¤t->sighand->siglock); | |
2176 | ||
2177 | /* Outside the lock because only this thread touches it. */ | |
2178 | sigandsets(&pending, ¤t->blocked, &pending); | |
2179 | ||
2180 | error = -EFAULT; | |
2181 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2182 | error = 0; | |
2183 | ||
2184 | out: | |
2185 | return error; | |
2186 | } | |
2187 | ||
17da2bd9 | 2188 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize) |
1da177e4 LT |
2189 | { |
2190 | return do_sigpending(set, sigsetsize); | |
2191 | } | |
2192 | ||
2193 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2194 | ||
2195 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2196 | { | |
2197 | int err; | |
2198 | ||
2199 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2200 | return -EFAULT; | |
2201 | if (from->si_code < 0) | |
2202 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2203 | ? -EFAULT : 0; | |
2204 | /* | |
2205 | * If you change siginfo_t structure, please be sure | |
2206 | * this code is fixed accordingly. | |
fba2afaa DL |
2207 | * Please remember to update the signalfd_copyinfo() function |
2208 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2209 | * It should never copy any pad contained in the structure |
2210 | * to avoid security leaks, but must copy the generic | |
2211 | * 3 ints plus the relevant union member. | |
2212 | */ | |
2213 | err = __put_user(from->si_signo, &to->si_signo); | |
2214 | err |= __put_user(from->si_errno, &to->si_errno); | |
2215 | err |= __put_user((short)from->si_code, &to->si_code); | |
2216 | switch (from->si_code & __SI_MASK) { | |
2217 | case __SI_KILL: | |
2218 | err |= __put_user(from->si_pid, &to->si_pid); | |
2219 | err |= __put_user(from->si_uid, &to->si_uid); | |
2220 | break; | |
2221 | case __SI_TIMER: | |
2222 | err |= __put_user(from->si_tid, &to->si_tid); | |
2223 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2224 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2225 | break; | |
2226 | case __SI_POLL: | |
2227 | err |= __put_user(from->si_band, &to->si_band); | |
2228 | err |= __put_user(from->si_fd, &to->si_fd); | |
2229 | break; | |
2230 | case __SI_FAULT: | |
2231 | err |= __put_user(from->si_addr, &to->si_addr); | |
2232 | #ifdef __ARCH_SI_TRAPNO | |
2233 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2234 | #endif |
2235 | #ifdef BUS_MCEERR_AO | |
2236 | /* | |
2237 | * Other callers might not initialize the si_lsb field, | |
2238 | * so check explicitely for the right codes here. | |
2239 | */ | |
2240 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2241 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2242 | #endif |
2243 | break; | |
2244 | case __SI_CHLD: | |
2245 | err |= __put_user(from->si_pid, &to->si_pid); | |
2246 | err |= __put_user(from->si_uid, &to->si_uid); | |
2247 | err |= __put_user(from->si_status, &to->si_status); | |
2248 | err |= __put_user(from->si_utime, &to->si_utime); | |
2249 | err |= __put_user(from->si_stime, &to->si_stime); | |
2250 | break; | |
2251 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2252 | case __SI_MESGQ: /* But this is */ | |
2253 | err |= __put_user(from->si_pid, &to->si_pid); | |
2254 | err |= __put_user(from->si_uid, &to->si_uid); | |
2255 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2256 | break; | |
2257 | default: /* this is just in case for now ... */ | |
2258 | err |= __put_user(from->si_pid, &to->si_pid); | |
2259 | err |= __put_user(from->si_uid, &to->si_uid); | |
2260 | break; | |
2261 | } | |
2262 | return err; | |
2263 | } | |
2264 | ||
2265 | #endif | |
2266 | ||
17da2bd9 HC |
2267 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2268 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2269 | size_t, sigsetsize) | |
1da177e4 LT |
2270 | { |
2271 | int ret, sig; | |
2272 | sigset_t these; | |
2273 | struct timespec ts; | |
2274 | siginfo_t info; | |
2275 | long timeout = 0; | |
2276 | ||
2277 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2278 | if (sigsetsize != sizeof(sigset_t)) | |
2279 | return -EINVAL; | |
2280 | ||
2281 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2282 | return -EFAULT; | |
2283 | ||
2284 | /* | |
2285 | * Invert the set of allowed signals to get those we | |
2286 | * want to block. | |
2287 | */ | |
2288 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2289 | signotset(&these); | |
2290 | ||
2291 | if (uts) { | |
2292 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2293 | return -EFAULT; | |
2294 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2295 | || ts.tv_sec < 0) | |
2296 | return -EINVAL; | |
2297 | } | |
2298 | ||
2299 | spin_lock_irq(¤t->sighand->siglock); | |
2300 | sig = dequeue_signal(current, &these, &info); | |
2301 | if (!sig) { | |
2302 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2303 | if (uts) | |
2304 | timeout = (timespec_to_jiffies(&ts) | |
2305 | + (ts.tv_sec || ts.tv_nsec)); | |
2306 | ||
2307 | if (timeout) { | |
2308 | /* None ready -- temporarily unblock those we're | |
2309 | * interested while we are sleeping in so that we'll | |
2310 | * be awakened when they arrive. */ | |
2311 | current->real_blocked = current->blocked; | |
2312 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2313 | recalc_sigpending(); | |
2314 | spin_unlock_irq(¤t->sighand->siglock); | |
2315 | ||
75bcc8c5 | 2316 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2317 | |
1da177e4 LT |
2318 | spin_lock_irq(¤t->sighand->siglock); |
2319 | sig = dequeue_signal(current, &these, &info); | |
2320 | current->blocked = current->real_blocked; | |
2321 | siginitset(¤t->real_blocked, 0); | |
2322 | recalc_sigpending(); | |
2323 | } | |
2324 | } | |
2325 | spin_unlock_irq(¤t->sighand->siglock); | |
2326 | ||
2327 | if (sig) { | |
2328 | ret = sig; | |
2329 | if (uinfo) { | |
2330 | if (copy_siginfo_to_user(uinfo, &info)) | |
2331 | ret = -EFAULT; | |
2332 | } | |
2333 | } else { | |
2334 | ret = -EAGAIN; | |
2335 | if (timeout) | |
2336 | ret = -EINTR; | |
2337 | } | |
2338 | ||
2339 | return ret; | |
2340 | } | |
2341 | ||
17da2bd9 | 2342 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2343 | { |
2344 | struct siginfo info; | |
2345 | ||
2346 | info.si_signo = sig; | |
2347 | info.si_errno = 0; | |
2348 | info.si_code = SI_USER; | |
b488893a | 2349 | info.si_pid = task_tgid_vnr(current); |
76aac0e9 | 2350 | info.si_uid = current_uid(); |
1da177e4 LT |
2351 | |
2352 | return kill_something_info(sig, &info, pid); | |
2353 | } | |
2354 | ||
30b4ae8a TG |
2355 | static int |
2356 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2357 | { |
1da177e4 | 2358 | struct task_struct *p; |
30b4ae8a | 2359 | int error = -ESRCH; |
1da177e4 | 2360 | |
3547ff3a | 2361 | rcu_read_lock(); |
228ebcbe | 2362 | p = find_task_by_vpid(pid); |
b488893a | 2363 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2364 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2365 | /* |
2366 | * The null signal is a permissions and process existence | |
2367 | * probe. No signal is actually delivered. | |
2368 | */ | |
4a30debf ON |
2369 | if (!error && sig) { |
2370 | error = do_send_sig_info(sig, info, p, false); | |
2371 | /* | |
2372 | * If lock_task_sighand() failed we pretend the task | |
2373 | * dies after receiving the signal. The window is tiny, | |
2374 | * and the signal is private anyway. | |
2375 | */ | |
2376 | if (unlikely(error == -ESRCH)) | |
2377 | error = 0; | |
1da177e4 LT |
2378 | } |
2379 | } | |
3547ff3a | 2380 | rcu_read_unlock(); |
6dd69f10 | 2381 | |
1da177e4 LT |
2382 | return error; |
2383 | } | |
2384 | ||
30b4ae8a TG |
2385 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2386 | { | |
2387 | struct siginfo info; | |
2388 | ||
2389 | info.si_signo = sig; | |
2390 | info.si_errno = 0; | |
2391 | info.si_code = SI_TKILL; | |
2392 | info.si_pid = task_tgid_vnr(current); | |
2393 | info.si_uid = current_uid(); | |
2394 | ||
2395 | return do_send_specific(tgid, pid, sig, &info); | |
2396 | } | |
2397 | ||
6dd69f10 VL |
2398 | /** |
2399 | * sys_tgkill - send signal to one specific thread | |
2400 | * @tgid: the thread group ID of the thread | |
2401 | * @pid: the PID of the thread | |
2402 | * @sig: signal to be sent | |
2403 | * | |
72fd4a35 | 2404 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2405 | * exists but it's not belonging to the target process anymore. This |
2406 | * method solves the problem of threads exiting and PIDs getting reused. | |
2407 | */ | |
a5f8fa9e | 2408 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2409 | { |
2410 | /* This is only valid for single tasks */ | |
2411 | if (pid <= 0 || tgid <= 0) | |
2412 | return -EINVAL; | |
2413 | ||
2414 | return do_tkill(tgid, pid, sig); | |
2415 | } | |
2416 | ||
1da177e4 LT |
2417 | /* |
2418 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2419 | */ | |
a5f8fa9e | 2420 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2421 | { |
1da177e4 LT |
2422 | /* This is only valid for single tasks */ |
2423 | if (pid <= 0) | |
2424 | return -EINVAL; | |
2425 | ||
6dd69f10 | 2426 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2427 | } |
2428 | ||
a5f8fa9e HC |
2429 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2430 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2431 | { |
2432 | siginfo_t info; | |
2433 | ||
2434 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2435 | return -EFAULT; | |
2436 | ||
2437 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2438 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2439 | */ | |
243b422a | 2440 | if (info.si_code >= 0 || info.si_code == SI_TKILL) { |
da48524e JT |
2441 | /* We used to allow any < 0 si_code */ |
2442 | WARN_ON_ONCE(info.si_code < 0); | |
1da177e4 | 2443 | return -EPERM; |
da48524e | 2444 | } |
1da177e4 LT |
2445 | info.si_signo = sig; |
2446 | ||
2447 | /* POSIX.1b doesn't mention process groups. */ | |
2448 | return kill_proc_info(sig, &info, pid); | |
2449 | } | |
2450 | ||
62ab4505 TG |
2451 | long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
2452 | { | |
2453 | /* This is only valid for single tasks */ | |
2454 | if (pid <= 0 || tgid <= 0) | |
2455 | return -EINVAL; | |
2456 | ||
2457 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2458 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2459 | */ | |
243b422a | 2460 | if (info->si_code >= 0 || info->si_code == SI_TKILL) { |
da48524e JT |
2461 | /* We used to allow any < 0 si_code */ |
2462 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 2463 | return -EPERM; |
da48524e | 2464 | } |
62ab4505 TG |
2465 | info->si_signo = sig; |
2466 | ||
2467 | return do_send_specific(tgid, pid, sig, info); | |
2468 | } | |
2469 | ||
2470 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
2471 | siginfo_t __user *, uinfo) | |
2472 | { | |
2473 | siginfo_t info; | |
2474 | ||
2475 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2476 | return -EFAULT; | |
2477 | ||
2478 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
2479 | } | |
2480 | ||
88531f72 | 2481 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 2482 | { |
93585eea | 2483 | struct task_struct *t = current; |
1da177e4 | 2484 | struct k_sigaction *k; |
71fabd5e | 2485 | sigset_t mask; |
1da177e4 | 2486 | |
7ed20e1a | 2487 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2488 | return -EINVAL; |
2489 | ||
93585eea | 2490 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
2491 | |
2492 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2493 | if (oact) |
2494 | *oact = *k; | |
2495 | ||
2496 | if (act) { | |
9ac95f2f ON |
2497 | sigdelsetmask(&act->sa.sa_mask, |
2498 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2499 | *k = *act; |
1da177e4 LT |
2500 | /* |
2501 | * POSIX 3.3.1.3: | |
2502 | * "Setting a signal action to SIG_IGN for a signal that is | |
2503 | * pending shall cause the pending signal to be discarded, | |
2504 | * whether or not it is blocked." | |
2505 | * | |
2506 | * "Setting a signal action to SIG_DFL for a signal that is | |
2507 | * pending and whose default action is to ignore the signal | |
2508 | * (for example, SIGCHLD), shall cause the pending signal to | |
2509 | * be discarded, whether or not it is blocked" | |
2510 | */ | |
35de254d | 2511 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
2512 | sigemptyset(&mask); |
2513 | sigaddset(&mask, sig); | |
2514 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2515 | do { |
71fabd5e | 2516 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2517 | t = next_thread(t); |
2518 | } while (t != current); | |
1da177e4 | 2519 | } |
1da177e4 LT |
2520 | } |
2521 | ||
2522 | spin_unlock_irq(¤t->sighand->siglock); | |
2523 | return 0; | |
2524 | } | |
2525 | ||
2526 | int | |
2527 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2528 | { | |
2529 | stack_t oss; | |
2530 | int error; | |
2531 | ||
0083fc2c LT |
2532 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
2533 | oss.ss_size = current->sas_ss_size; | |
2534 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
2535 | |
2536 | if (uss) { | |
2537 | void __user *ss_sp; | |
2538 | size_t ss_size; | |
2539 | int ss_flags; | |
2540 | ||
2541 | error = -EFAULT; | |
0dd8486b LT |
2542 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
2543 | goto out; | |
2544 | error = __get_user(ss_sp, &uss->ss_sp) | | |
2545 | __get_user(ss_flags, &uss->ss_flags) | | |
2546 | __get_user(ss_size, &uss->ss_size); | |
2547 | if (error) | |
1da177e4 LT |
2548 | goto out; |
2549 | ||
2550 | error = -EPERM; | |
2551 | if (on_sig_stack(sp)) | |
2552 | goto out; | |
2553 | ||
2554 | error = -EINVAL; | |
2555 | /* | |
2556 | * | |
2557 | * Note - this code used to test ss_flags incorrectly | |
2558 | * old code may have been written using ss_flags==0 | |
2559 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2560 | * way that worked) - this fix preserves that older | |
2561 | * mechanism | |
2562 | */ | |
2563 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2564 | goto out; | |
2565 | ||
2566 | if (ss_flags == SS_DISABLE) { | |
2567 | ss_size = 0; | |
2568 | ss_sp = NULL; | |
2569 | } else { | |
2570 | error = -ENOMEM; | |
2571 | if (ss_size < MINSIGSTKSZ) | |
2572 | goto out; | |
2573 | } | |
2574 | ||
2575 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2576 | current->sas_ss_size = ss_size; | |
2577 | } | |
2578 | ||
0083fc2c | 2579 | error = 0; |
1da177e4 LT |
2580 | if (uoss) { |
2581 | error = -EFAULT; | |
0083fc2c | 2582 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 2583 | goto out; |
0083fc2c LT |
2584 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
2585 | __put_user(oss.ss_size, &uoss->ss_size) | | |
2586 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
2587 | } |
2588 | ||
1da177e4 LT |
2589 | out: |
2590 | return error; | |
2591 | } | |
2592 | ||
2593 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2594 | ||
b290ebe2 | 2595 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 LT |
2596 | { |
2597 | return do_sigpending(set, sizeof(*set)); | |
2598 | } | |
2599 | ||
2600 | #endif | |
2601 | ||
2602 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2603 | /* Some platforms have their own version with special arguments others | |
2604 | support only sys_rt_sigprocmask. */ | |
2605 | ||
b290ebe2 HC |
2606 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set, |
2607 | old_sigset_t __user *, oset) | |
1da177e4 LT |
2608 | { |
2609 | int error; | |
2610 | old_sigset_t old_set, new_set; | |
2611 | ||
2612 | if (set) { | |
2613 | error = -EFAULT; | |
2614 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2615 | goto out; | |
2616 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2617 | ||
2618 | spin_lock_irq(¤t->sighand->siglock); | |
2619 | old_set = current->blocked.sig[0]; | |
2620 | ||
2621 | error = 0; | |
2622 | switch (how) { | |
2623 | default: | |
2624 | error = -EINVAL; | |
2625 | break; | |
2626 | case SIG_BLOCK: | |
2627 | sigaddsetmask(¤t->blocked, new_set); | |
2628 | break; | |
2629 | case SIG_UNBLOCK: | |
2630 | sigdelsetmask(¤t->blocked, new_set); | |
2631 | break; | |
2632 | case SIG_SETMASK: | |
2633 | current->blocked.sig[0] = new_set; | |
2634 | break; | |
2635 | } | |
2636 | ||
2637 | recalc_sigpending(); | |
2638 | spin_unlock_irq(¤t->sighand->siglock); | |
2639 | if (error) | |
2640 | goto out; | |
2641 | if (oset) | |
2642 | goto set_old; | |
2643 | } else if (oset) { | |
2644 | old_set = current->blocked.sig[0]; | |
2645 | set_old: | |
2646 | error = -EFAULT; | |
2647 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2648 | goto out; | |
2649 | } | |
2650 | error = 0; | |
2651 | out: | |
2652 | return error; | |
2653 | } | |
2654 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2655 | ||
2656 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
d4e82042 HC |
2657 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
2658 | const struct sigaction __user *, act, | |
2659 | struct sigaction __user *, oact, | |
2660 | size_t, sigsetsize) | |
1da177e4 LT |
2661 | { |
2662 | struct k_sigaction new_sa, old_sa; | |
2663 | int ret = -EINVAL; | |
2664 | ||
2665 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2666 | if (sigsetsize != sizeof(sigset_t)) | |
2667 | goto out; | |
2668 | ||
2669 | if (act) { | |
2670 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2671 | return -EFAULT; | |
2672 | } | |
2673 | ||
2674 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2675 | ||
2676 | if (!ret && oact) { | |
2677 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2678 | return -EFAULT; | |
2679 | } | |
2680 | out: | |
2681 | return ret; | |
2682 | } | |
2683 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2684 | ||
2685 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2686 | ||
2687 | /* | |
2688 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2689 | */ | |
a5f8fa9e | 2690 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
2691 | { |
2692 | /* SMP safe */ | |
2693 | return current->blocked.sig[0]; | |
2694 | } | |
2695 | ||
a5f8fa9e | 2696 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 LT |
2697 | { |
2698 | int old; | |
2699 | ||
2700 | spin_lock_irq(¤t->sighand->siglock); | |
2701 | old = current->blocked.sig[0]; | |
2702 | ||
2703 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2704 | sigmask(SIGSTOP))); | |
2705 | recalc_sigpending(); | |
2706 | spin_unlock_irq(¤t->sighand->siglock); | |
2707 | ||
2708 | return old; | |
2709 | } | |
2710 | #endif /* __ARCH_WANT_SGETMASK */ | |
2711 | ||
2712 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2713 | /* | |
2714 | * For backwards compatibility. Functionality superseded by sigaction. | |
2715 | */ | |
a5f8fa9e | 2716 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
2717 | { |
2718 | struct k_sigaction new_sa, old_sa; | |
2719 | int ret; | |
2720 | ||
2721 | new_sa.sa.sa_handler = handler; | |
2722 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2723 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2724 | |
2725 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2726 | ||
2727 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2728 | } | |
2729 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2730 | ||
2731 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2732 | ||
a5f8fa9e | 2733 | SYSCALL_DEFINE0(pause) |
1da177e4 LT |
2734 | { |
2735 | current->state = TASK_INTERRUPTIBLE; | |
2736 | schedule(); | |
2737 | return -ERESTARTNOHAND; | |
2738 | } | |
2739 | ||
2740 | #endif | |
2741 | ||
150256d8 | 2742 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
d4e82042 | 2743 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
2744 | { |
2745 | sigset_t newset; | |
2746 | ||
2747 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2748 | if (sigsetsize != sizeof(sigset_t)) | |
2749 | return -EINVAL; | |
2750 | ||
2751 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2752 | return -EFAULT; | |
2753 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2754 | ||
2755 | spin_lock_irq(¤t->sighand->siglock); | |
2756 | current->saved_sigmask = current->blocked; | |
2757 | current->blocked = newset; | |
2758 | recalc_sigpending(); | |
2759 | spin_unlock_irq(¤t->sighand->siglock); | |
2760 | ||
2761 | current->state = TASK_INTERRUPTIBLE; | |
2762 | schedule(); | |
4e4c22c7 | 2763 | set_restore_sigmask(); |
150256d8 DW |
2764 | return -ERESTARTNOHAND; |
2765 | } | |
2766 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2767 | ||
f269fdd1 DH |
2768 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2769 | { | |
2770 | return NULL; | |
2771 | } | |
2772 | ||
1da177e4 LT |
2773 | void __init signals_init(void) |
2774 | { | |
0a31bd5f | 2775 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2776 | } |
67fc4e0c JW |
2777 | |
2778 | #ifdef CONFIG_KGDB_KDB | |
2779 | #include <linux/kdb.h> | |
2780 | /* | |
2781 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
2782 | * signal internals. This function checks if the required locks are | |
2783 | * available before calling the main signal code, to avoid kdb | |
2784 | * deadlocks. | |
2785 | */ | |
2786 | void | |
2787 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
2788 | { | |
2789 | static struct task_struct *kdb_prev_t; | |
2790 | int sig, new_t; | |
2791 | if (!spin_trylock(&t->sighand->siglock)) { | |
2792 | kdb_printf("Can't do kill command now.\n" | |
2793 | "The sigmask lock is held somewhere else in " | |
2794 | "kernel, try again later\n"); | |
2795 | return; | |
2796 | } | |
2797 | spin_unlock(&t->sighand->siglock); | |
2798 | new_t = kdb_prev_t != t; | |
2799 | kdb_prev_t = t; | |
2800 | if (t->state != TASK_RUNNING && new_t) { | |
2801 | kdb_printf("Process is not RUNNING, sending a signal from " | |
2802 | "kdb risks deadlock\n" | |
2803 | "on the run queue locks. " | |
2804 | "The signal has _not_ been sent.\n" | |
2805 | "Reissue the kill command if you want to risk " | |
2806 | "the deadlock.\n"); | |
2807 | return; | |
2808 | } | |
2809 | sig = info->si_signo; | |
2810 | if (send_sig_info(sig, info, t)) | |
2811 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
2812 | sig, t->pid); | |
2813 | else | |
2814 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
2815 | } | |
2816 | #endif /* CONFIG_KGDB_KDB */ |