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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 LT |
13 | #include <linux/slab.h> |
14 | #include <linux/module.h> | |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
20 | #include <linux/security.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/ptrace.h> | |
7ed20e1a | 23 | #include <linux/signal.h> |
fba2afaa | 24 | #include <linux/signalfd.h> |
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 | |
5aba085e | 229 | * appropriate 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 | ||
5aba085e RD |
378 | /* |
379 | * Notify the system that a driver wants to block all signals for this | |
1da177e4 LT |
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 | |
5aba085e RD |
385 | * can use to determine if the signal should be blocked or not. |
386 | */ | |
1da177e4 LT |
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 { |
5aba085e RD |
437 | /* |
438 | * Ok, it wasn't in the queue. This must be | |
439 | * a fast-pathed signal or we must have been | |
440 | * out of queue space. So zero out the info. | |
1da177e4 | 441 | */ |
1da177e4 LT |
442 | info->si_signo = sig; |
443 | info->si_errno = 0; | |
7486e5d9 | 444 | info->si_code = SI_USER; |
1da177e4 LT |
445 | info->si_pid = 0; |
446 | info->si_uid = 0; | |
447 | } | |
1da177e4 LT |
448 | } |
449 | ||
450 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
451 | siginfo_t *info) | |
452 | { | |
27d91e07 | 453 | int sig = next_signal(pending, mask); |
1da177e4 | 454 | |
1da177e4 LT |
455 | if (sig) { |
456 | if (current->notifier) { | |
457 | if (sigismember(current->notifier_mask, sig)) { | |
458 | if (!(current->notifier)(current->notifier_data)) { | |
459 | clear_thread_flag(TIF_SIGPENDING); | |
460 | return 0; | |
461 | } | |
462 | } | |
463 | } | |
464 | ||
100360f0 | 465 | collect_signal(sig, pending, info); |
1da177e4 | 466 | } |
1da177e4 LT |
467 | |
468 | return sig; | |
469 | } | |
470 | ||
471 | /* | |
5aba085e | 472 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
473 | * expected to free it. |
474 | * | |
475 | * All callers have to hold the siglock. | |
476 | */ | |
477 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
478 | { | |
c5363d03 | 479 | int signr; |
caec4e8d BH |
480 | |
481 | /* We only dequeue private signals from ourselves, we don't let | |
482 | * signalfd steal them | |
483 | */ | |
b8fceee1 | 484 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 485 | if (!signr) { |
1da177e4 LT |
486 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
487 | mask, info); | |
8bfd9a7a TG |
488 | /* |
489 | * itimer signal ? | |
490 | * | |
491 | * itimers are process shared and we restart periodic | |
492 | * itimers in the signal delivery path to prevent DoS | |
493 | * attacks in the high resolution timer case. This is | |
5aba085e | 494 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
495 | * itimers, as the SIGALRM is a legacy signal and only |
496 | * queued once. Changing the restart behaviour to | |
497 | * restart the timer in the signal dequeue path is | |
498 | * reducing the timer noise on heavy loaded !highres | |
499 | * systems too. | |
500 | */ | |
501 | if (unlikely(signr == SIGALRM)) { | |
502 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
503 | ||
504 | if (!hrtimer_is_queued(tmr) && | |
505 | tsk->signal->it_real_incr.tv64 != 0) { | |
506 | hrtimer_forward(tmr, tmr->base->get_time(), | |
507 | tsk->signal->it_real_incr); | |
508 | hrtimer_restart(tmr); | |
509 | } | |
510 | } | |
511 | } | |
c5363d03 | 512 | |
b8fceee1 | 513 | recalc_sigpending(); |
c5363d03 PE |
514 | if (!signr) |
515 | return 0; | |
516 | ||
517 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
518 | /* |
519 | * Set a marker that we have dequeued a stop signal. Our | |
520 | * caller might release the siglock and then the pending | |
521 | * stop signal it is about to process is no longer in the | |
522 | * pending bitmasks, but must still be cleared by a SIGCONT | |
523 | * (and overruled by a SIGKILL). So those cases clear this | |
524 | * shared flag after we've set it. Note that this flag may | |
525 | * remain set after the signal we return is ignored or | |
526 | * handled. That doesn't matter because its only purpose | |
527 | * is to alert stop-signal processing code when another | |
528 | * processor has come along and cleared the flag. | |
529 | */ | |
92413d77 | 530 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; |
8bfd9a7a | 531 | } |
c5363d03 | 532 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
533 | /* |
534 | * Release the siglock to ensure proper locking order | |
535 | * of timer locks outside of siglocks. Note, we leave | |
536 | * irqs disabled here, since the posix-timers code is | |
537 | * about to disable them again anyway. | |
538 | */ | |
539 | spin_unlock(&tsk->sighand->siglock); | |
540 | do_schedule_next_timer(info); | |
541 | spin_lock(&tsk->sighand->siglock); | |
542 | } | |
543 | return signr; | |
544 | } | |
545 | ||
546 | /* | |
547 | * Tell a process that it has a new active signal.. | |
548 | * | |
549 | * NOTE! we rely on the previous spin_lock to | |
550 | * lock interrupts for us! We can only be called with | |
551 | * "siglock" held, and the local interrupt must | |
552 | * have been disabled when that got acquired! | |
553 | * | |
554 | * No need to set need_resched since signal event passing | |
555 | * goes through ->blocked | |
556 | */ | |
557 | void signal_wake_up(struct task_struct *t, int resume) | |
558 | { | |
559 | unsigned int mask; | |
560 | ||
561 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
562 | ||
563 | /* | |
f021a3c2 MW |
564 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
565 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
566 | * executing another processor and just now entering stopped state. |
567 | * By using wake_up_state, we ensure the process will wake up and | |
568 | * handle its death signal. | |
569 | */ | |
570 | mask = TASK_INTERRUPTIBLE; | |
571 | if (resume) | |
f021a3c2 | 572 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
573 | if (!wake_up_state(t, mask)) |
574 | kick_process(t); | |
575 | } | |
576 | ||
71fabd5e GA |
577 | /* |
578 | * Remove signals in mask from the pending set and queue. | |
579 | * Returns 1 if any signals were found. | |
580 | * | |
581 | * All callers must be holding the siglock. | |
582 | * | |
583 | * This version takes a sigset mask and looks at all signals, | |
584 | * not just those in the first mask word. | |
585 | */ | |
586 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
587 | { | |
588 | struct sigqueue *q, *n; | |
589 | sigset_t m; | |
590 | ||
591 | sigandsets(&m, mask, &s->signal); | |
592 | if (sigisemptyset(&m)) | |
593 | return 0; | |
594 | ||
595 | signandsets(&s->signal, &s->signal, mask); | |
596 | list_for_each_entry_safe(q, n, &s->list, list) { | |
597 | if (sigismember(mask, q->info.si_signo)) { | |
598 | list_del_init(&q->list); | |
599 | __sigqueue_free(q); | |
600 | } | |
601 | } | |
602 | return 1; | |
603 | } | |
1da177e4 LT |
604 | /* |
605 | * Remove signals in mask from the pending set and queue. | |
606 | * Returns 1 if any signals were found. | |
607 | * | |
608 | * All callers must be holding the siglock. | |
609 | */ | |
610 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
611 | { | |
612 | struct sigqueue *q, *n; | |
613 | ||
614 | if (!sigtestsetmask(&s->signal, mask)) | |
615 | return 0; | |
616 | ||
617 | sigdelsetmask(&s->signal, mask); | |
618 | list_for_each_entry_safe(q, n, &s->list, list) { | |
619 | if (q->info.si_signo < SIGRTMIN && | |
620 | (mask & sigmask(q->info.si_signo))) { | |
621 | list_del_init(&q->list); | |
622 | __sigqueue_free(q); | |
623 | } | |
624 | } | |
625 | return 1; | |
626 | } | |
627 | ||
614c517d ON |
628 | static inline int is_si_special(const struct siginfo *info) |
629 | { | |
630 | return info <= SEND_SIG_FORCED; | |
631 | } | |
632 | ||
633 | static inline bool si_fromuser(const struct siginfo *info) | |
634 | { | |
635 | return info == SEND_SIG_NOINFO || | |
636 | (!is_si_special(info) && SI_FROMUSER(info)); | |
637 | } | |
638 | ||
39fd3393 SH |
639 | /* |
640 | * called with RCU read lock from check_kill_permission() | |
641 | */ | |
642 | static int kill_ok_by_cred(struct task_struct *t) | |
643 | { | |
644 | const struct cred *cred = current_cred(); | |
645 | const struct cred *tcred = __task_cred(t); | |
646 | ||
647 | if (cred->user->user_ns == tcred->user->user_ns && | |
648 | (cred->euid == tcred->suid || | |
649 | cred->euid == tcred->uid || | |
650 | cred->uid == tcred->suid || | |
651 | cred->uid == tcred->uid)) | |
652 | return 1; | |
653 | ||
654 | if (ns_capable(tcred->user->user_ns, CAP_KILL)) | |
655 | return 1; | |
656 | ||
657 | return 0; | |
658 | } | |
659 | ||
1da177e4 LT |
660 | /* |
661 | * Bad permissions for sending the signal | |
694f690d | 662 | * - the caller must hold the RCU read lock |
1da177e4 LT |
663 | */ |
664 | static int check_kill_permission(int sig, struct siginfo *info, | |
665 | struct task_struct *t) | |
666 | { | |
2e2ba22e | 667 | struct pid *sid; |
3b5e9e53 ON |
668 | int error; |
669 | ||
7ed20e1a | 670 | if (!valid_signal(sig)) |
3b5e9e53 ON |
671 | return -EINVAL; |
672 | ||
614c517d | 673 | if (!si_fromuser(info)) |
3b5e9e53 | 674 | return 0; |
e54dc243 | 675 | |
3b5e9e53 ON |
676 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
677 | if (error) | |
1da177e4 | 678 | return error; |
3b5e9e53 | 679 | |
065add39 | 680 | if (!same_thread_group(current, t) && |
39fd3393 | 681 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
682 | switch (sig) { |
683 | case SIGCONT: | |
2e2ba22e | 684 | sid = task_session(t); |
2e2ba22e ON |
685 | /* |
686 | * We don't return the error if sid == NULL. The | |
687 | * task was unhashed, the caller must notice this. | |
688 | */ | |
689 | if (!sid || sid == task_session(current)) | |
690 | break; | |
691 | default: | |
692 | return -EPERM; | |
693 | } | |
694 | } | |
c2f0c7c3 | 695 | |
e54dc243 | 696 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
697 | } |
698 | ||
1da177e4 | 699 | /* |
7e695a5e ON |
700 | * Handle magic process-wide effects of stop/continue signals. Unlike |
701 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
702 | * time regardless of blocking, ignoring, or handling. This does the |
703 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
704 | * signals. The process stop is done as a signal action for SIG_DFL. |
705 | * | |
706 | * Returns true if the signal should be actually delivered, otherwise | |
707 | * it should be dropped. | |
1da177e4 | 708 | */ |
921cf9f6 | 709 | static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns) |
1da177e4 | 710 | { |
ad16a460 | 711 | struct signal_struct *signal = p->signal; |
1da177e4 LT |
712 | struct task_struct *t; |
713 | ||
7e695a5e | 714 | if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) { |
1da177e4 | 715 | /* |
7e695a5e | 716 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 717 | */ |
7e695a5e | 718 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
719 | /* |
720 | * This is a stop signal. Remove SIGCONT from all queues. | |
721 | */ | |
ad16a460 | 722 | rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); |
1da177e4 LT |
723 | t = p; |
724 | do { | |
725 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
ad16a460 | 726 | } while_each_thread(p, t); |
1da177e4 | 727 | } else if (sig == SIGCONT) { |
fc321d2e | 728 | unsigned int why; |
1da177e4 LT |
729 | /* |
730 | * Remove all stop signals from all queues, | |
731 | * and wake all threads. | |
732 | */ | |
ad16a460 | 733 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
734 | t = p; |
735 | do { | |
736 | unsigned int state; | |
737 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
1da177e4 LT |
738 | /* |
739 | * If there is a handler for SIGCONT, we must make | |
740 | * sure that no thread returns to user mode before | |
741 | * we post the signal, in case it was the only | |
742 | * thread eligible to run the signal handler--then | |
743 | * it must not do anything between resuming and | |
744 | * running the handler. With the TIF_SIGPENDING | |
745 | * flag set, the thread will pause and acquire the | |
746 | * siglock that we hold now and until we've queued | |
fc321d2e | 747 | * the pending signal. |
1da177e4 LT |
748 | * |
749 | * Wake up the stopped thread _after_ setting | |
750 | * TIF_SIGPENDING | |
751 | */ | |
f021a3c2 | 752 | state = __TASK_STOPPED; |
1da177e4 LT |
753 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { |
754 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
755 | state |= TASK_INTERRUPTIBLE; | |
756 | } | |
757 | wake_up_state(t, state); | |
ad16a460 | 758 | } while_each_thread(p, t); |
1da177e4 | 759 | |
fc321d2e ON |
760 | /* |
761 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
762 | * | |
763 | * If we were in the middle of a group stop, we pretend it | |
764 | * was already finished, and then continued. Since SIGCHLD | |
765 | * doesn't queue we report only CLD_STOPPED, as if the next | |
766 | * CLD_CONTINUED was dropped. | |
767 | */ | |
768 | why = 0; | |
ad16a460 | 769 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 770 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 771 | else if (signal->group_stop_count) |
fc321d2e ON |
772 | why |= SIGNAL_CLD_STOPPED; |
773 | ||
774 | if (why) { | |
021e1ae3 | 775 | /* |
ae6d2ed7 | 776 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
777 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
778 | * notify its parent. See get_signal_to_deliver(). | |
779 | */ | |
ad16a460 ON |
780 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
781 | signal->group_stop_count = 0; | |
782 | signal->group_exit_code = 0; | |
1da177e4 LT |
783 | } else { |
784 | /* | |
785 | * We are not stopped, but there could be a stop | |
786 | * signal in the middle of being processed after | |
787 | * being removed from the queue. Clear that too. | |
788 | */ | |
ad16a460 | 789 | signal->flags &= ~SIGNAL_STOP_DEQUEUED; |
1da177e4 | 790 | } |
1da177e4 | 791 | } |
7e695a5e | 792 | |
921cf9f6 | 793 | return !sig_ignored(p, sig, from_ancestor_ns); |
1da177e4 LT |
794 | } |
795 | ||
71f11dc0 ON |
796 | /* |
797 | * Test if P wants to take SIG. After we've checked all threads with this, | |
798 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
799 | * blocking SIG were ruled out because they are not running and already | |
800 | * have pending signals. Such threads will dequeue from the shared queue | |
801 | * as soon as they're available, so putting the signal on the shared queue | |
802 | * will be equivalent to sending it to one such thread. | |
803 | */ | |
804 | static inline int wants_signal(int sig, struct task_struct *p) | |
805 | { | |
806 | if (sigismember(&p->blocked, sig)) | |
807 | return 0; | |
808 | if (p->flags & PF_EXITING) | |
809 | return 0; | |
810 | if (sig == SIGKILL) | |
811 | return 1; | |
812 | if (task_is_stopped_or_traced(p)) | |
813 | return 0; | |
814 | return task_curr(p) || !signal_pending(p); | |
815 | } | |
816 | ||
5fcd835b | 817 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
818 | { |
819 | struct signal_struct *signal = p->signal; | |
820 | struct task_struct *t; | |
821 | ||
822 | /* | |
823 | * Now find a thread we can wake up to take the signal off the queue. | |
824 | * | |
825 | * If the main thread wants the signal, it gets first crack. | |
826 | * Probably the least surprising to the average bear. | |
827 | */ | |
828 | if (wants_signal(sig, p)) | |
829 | t = p; | |
5fcd835b | 830 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
831 | /* |
832 | * There is just one thread and it does not need to be woken. | |
833 | * It will dequeue unblocked signals before it runs again. | |
834 | */ | |
835 | return; | |
836 | else { | |
837 | /* | |
838 | * Otherwise try to find a suitable thread. | |
839 | */ | |
840 | t = signal->curr_target; | |
841 | while (!wants_signal(sig, t)) { | |
842 | t = next_thread(t); | |
843 | if (t == signal->curr_target) | |
844 | /* | |
845 | * No thread needs to be woken. | |
846 | * Any eligible threads will see | |
847 | * the signal in the queue soon. | |
848 | */ | |
849 | return; | |
850 | } | |
851 | signal->curr_target = t; | |
852 | } | |
853 | ||
854 | /* | |
855 | * Found a killable thread. If the signal will be fatal, | |
856 | * then start taking the whole group down immediately. | |
857 | */ | |
fae5fa44 ON |
858 | if (sig_fatal(p, sig) && |
859 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 860 | !sigismember(&t->real_blocked, sig) && |
445a91d2 | 861 | (sig == SIGKILL || |
43918f2b | 862 | !tracehook_consider_fatal_signal(t, sig))) { |
71f11dc0 ON |
863 | /* |
864 | * This signal will be fatal to the whole group. | |
865 | */ | |
866 | if (!sig_kernel_coredump(sig)) { | |
867 | /* | |
868 | * Start a group exit and wake everybody up. | |
869 | * This way we don't have other threads | |
870 | * running and doing things after a slower | |
871 | * thread has the fatal signal pending. | |
872 | */ | |
873 | signal->flags = SIGNAL_GROUP_EXIT; | |
874 | signal->group_exit_code = sig; | |
875 | signal->group_stop_count = 0; | |
876 | t = p; | |
877 | do { | |
878 | sigaddset(&t->pending.signal, SIGKILL); | |
879 | signal_wake_up(t, 1); | |
880 | } while_each_thread(p, t); | |
881 | return; | |
882 | } | |
883 | } | |
884 | ||
885 | /* | |
886 | * The signal is already in the shared-pending queue. | |
887 | * Tell the chosen thread to wake up and dequeue it. | |
888 | */ | |
889 | signal_wake_up(t, sig == SIGKILL); | |
890 | return; | |
891 | } | |
892 | ||
af7fff9c PE |
893 | static inline int legacy_queue(struct sigpending *signals, int sig) |
894 | { | |
895 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
896 | } | |
897 | ||
7978b567 SB |
898 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
899 | int group, int from_ancestor_ns) | |
1da177e4 | 900 | { |
2ca3515a | 901 | struct sigpending *pending; |
6e65acba | 902 | struct sigqueue *q; |
7a0aeb14 | 903 | int override_rlimit; |
1da177e4 | 904 | |
d1eb650f | 905 | trace_signal_generate(sig, info, t); |
0a16b607 | 906 | |
6e65acba | 907 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 SB |
908 | |
909 | if (!prepare_signal(sig, t, from_ancestor_ns)) | |
7e695a5e | 910 | return 0; |
2ca3515a ON |
911 | |
912 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
913 | /* |
914 | * Short-circuit ignored signals and support queuing | |
915 | * exactly one non-rt signal, so that we can get more | |
916 | * detailed information about the cause of the signal. | |
917 | */ | |
7e695a5e | 918 | if (legacy_queue(pending, sig)) |
2acb024d | 919 | return 0; |
1da177e4 LT |
920 | /* |
921 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
922 | * or SIGKILL. | |
923 | */ | |
b67a1b9e | 924 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
925 | goto out_set; |
926 | ||
5aba085e RD |
927 | /* |
928 | * Real-time signals must be queued if sent by sigqueue, or | |
929 | * some other real-time mechanism. It is implementation | |
930 | * defined whether kill() does so. We attempt to do so, on | |
931 | * the principle of least surprise, but since kill is not | |
932 | * allowed to fail with EAGAIN when low on memory we just | |
933 | * make sure at least one signal gets delivered and don't | |
934 | * pass on the info struct. | |
935 | */ | |
7a0aeb14 VN |
936 | if (sig < SIGRTMIN) |
937 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
938 | else | |
939 | override_rlimit = 0; | |
940 | ||
f84d49b2 | 941 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 942 | override_rlimit); |
1da177e4 | 943 | if (q) { |
2ca3515a | 944 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 945 | switch ((unsigned long) info) { |
b67a1b9e | 946 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
947 | q->info.si_signo = sig; |
948 | q->info.si_errno = 0; | |
949 | q->info.si_code = SI_USER; | |
9cd4fd10 | 950 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 951 | task_active_pid_ns(t)); |
76aac0e9 | 952 | q->info.si_uid = current_uid(); |
1da177e4 | 953 | break; |
b67a1b9e | 954 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
955 | q->info.si_signo = sig; |
956 | q->info.si_errno = 0; | |
957 | q->info.si_code = SI_KERNEL; | |
958 | q->info.si_pid = 0; | |
959 | q->info.si_uid = 0; | |
960 | break; | |
961 | default: | |
962 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
963 | if (from_ancestor_ns) |
964 | q->info.si_pid = 0; | |
1da177e4 LT |
965 | break; |
966 | } | |
621d3121 | 967 | } else if (!is_si_special(info)) { |
ba005e1f MH |
968 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
969 | /* | |
970 | * Queue overflow, abort. We may abort if the | |
971 | * signal was rt and sent by user using something | |
972 | * other than kill(). | |
973 | */ | |
974 | trace_signal_overflow_fail(sig, group, info); | |
1da177e4 | 975 | return -EAGAIN; |
ba005e1f MH |
976 | } else { |
977 | /* | |
978 | * This is a silent loss of information. We still | |
979 | * send the signal, but the *info bits are lost. | |
980 | */ | |
981 | trace_signal_lose_info(sig, group, info); | |
982 | } | |
1da177e4 LT |
983 | } |
984 | ||
985 | out_set: | |
53c30337 | 986 | signalfd_notify(t, sig); |
2ca3515a | 987 | sigaddset(&pending->signal, sig); |
4cd4b6d4 PE |
988 | complete_signal(sig, t, group); |
989 | return 0; | |
1da177e4 LT |
990 | } |
991 | ||
7978b567 SB |
992 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
993 | int group) | |
994 | { | |
921cf9f6 SB |
995 | int from_ancestor_ns = 0; |
996 | ||
997 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
998 | from_ancestor_ns = si_fromuser(info) && |
999 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1000 | #endif |
1001 | ||
1002 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1003 | } |
1004 | ||
45807a1d IM |
1005 | static void print_fatal_signal(struct pt_regs *regs, int signr) |
1006 | { | |
1007 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 1008 | current->comm, task_pid_nr(current), signr); |
45807a1d | 1009 | |
ca5cd877 | 1010 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 1011 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
1012 | { |
1013 | int i; | |
1014 | for (i = 0; i < 16; i++) { | |
1015 | unsigned char insn; | |
1016 | ||
b45c6e76 AK |
1017 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1018 | break; | |
45807a1d IM |
1019 | printk("%02x ", insn); |
1020 | } | |
1021 | } | |
1022 | #endif | |
1023 | printk("\n"); | |
3a9f84d3 | 1024 | preempt_disable(); |
45807a1d | 1025 | show_regs(regs); |
3a9f84d3 | 1026 | preempt_enable(); |
45807a1d IM |
1027 | } |
1028 | ||
1029 | static int __init setup_print_fatal_signals(char *str) | |
1030 | { | |
1031 | get_option (&str, &print_fatal_signals); | |
1032 | ||
1033 | return 1; | |
1034 | } | |
1035 | ||
1036 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1037 | |
4cd4b6d4 PE |
1038 | int |
1039 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1040 | { | |
1041 | return send_signal(sig, info, p, 1); | |
1042 | } | |
1043 | ||
1da177e4 LT |
1044 | static int |
1045 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1046 | { | |
4cd4b6d4 | 1047 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1048 | } |
1049 | ||
4a30debf ON |
1050 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1051 | bool group) | |
1052 | { | |
1053 | unsigned long flags; | |
1054 | int ret = -ESRCH; | |
1055 | ||
1056 | if (lock_task_sighand(p, &flags)) { | |
1057 | ret = send_signal(sig, info, p, group); | |
1058 | unlock_task_sighand(p, &flags); | |
1059 | } | |
1060 | ||
1061 | return ret; | |
1062 | } | |
1063 | ||
1da177e4 LT |
1064 | /* |
1065 | * Force a signal that the process can't ignore: if necessary | |
1066 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1067 | * |
1068 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1069 | * since we do not want to have a signal handler that was blocked | |
1070 | * be invoked when user space had explicitly blocked it. | |
1071 | * | |
80fe728d ON |
1072 | * We don't want to have recursive SIGSEGV's etc, for example, |
1073 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1074 | */ |
1da177e4 LT |
1075 | int |
1076 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1077 | { | |
1078 | unsigned long int flags; | |
ae74c3b6 LT |
1079 | int ret, blocked, ignored; |
1080 | struct k_sigaction *action; | |
1da177e4 LT |
1081 | |
1082 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1083 | action = &t->sighand->action[sig-1]; |
1084 | ignored = action->sa.sa_handler == SIG_IGN; | |
1085 | blocked = sigismember(&t->blocked, sig); | |
1086 | if (blocked || ignored) { | |
1087 | action->sa.sa_handler = SIG_DFL; | |
1088 | if (blocked) { | |
1089 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1090 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1091 | } |
1da177e4 | 1092 | } |
80fe728d ON |
1093 | if (action->sa.sa_handler == SIG_DFL) |
1094 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1095 | ret = specific_send_sig_info(sig, info, t); |
1096 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1097 | ||
1098 | return ret; | |
1099 | } | |
1100 | ||
1da177e4 LT |
1101 | /* |
1102 | * Nuke all other threads in the group. | |
1103 | */ | |
09faef11 | 1104 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1105 | { |
09faef11 ON |
1106 | struct task_struct *t = p; |
1107 | int count = 0; | |
1da177e4 | 1108 | |
1da177e4 LT |
1109 | p->signal->group_stop_count = 0; |
1110 | ||
09faef11 ON |
1111 | while_each_thread(p, t) { |
1112 | count++; | |
1113 | ||
1114 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1115 | if (t->exit_state) |
1116 | continue; | |
1da177e4 | 1117 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1118 | signal_wake_up(t, 1); |
1119 | } | |
09faef11 ON |
1120 | |
1121 | return count; | |
1da177e4 LT |
1122 | } |
1123 | ||
b8ed374e NK |
1124 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1125 | unsigned long *flags) | |
f63ee72e ON |
1126 | { |
1127 | struct sighand_struct *sighand; | |
1128 | ||
1406f2d3 | 1129 | rcu_read_lock(); |
f63ee72e ON |
1130 | for (;;) { |
1131 | sighand = rcu_dereference(tsk->sighand); | |
1132 | if (unlikely(sighand == NULL)) | |
1133 | break; | |
1134 | ||
1135 | spin_lock_irqsave(&sighand->siglock, *flags); | |
1136 | if (likely(sighand == tsk->sighand)) | |
1137 | break; | |
1138 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
1139 | } | |
1406f2d3 | 1140 | rcu_read_unlock(); |
f63ee72e ON |
1141 | |
1142 | return sighand; | |
1143 | } | |
1144 | ||
c69e8d9c DH |
1145 | /* |
1146 | * send signal info to all the members of a group | |
c69e8d9c | 1147 | */ |
1da177e4 LT |
1148 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1149 | { | |
694f690d DH |
1150 | int ret; |
1151 | ||
1152 | rcu_read_lock(); | |
1153 | ret = check_kill_permission(sig, info, p); | |
1154 | rcu_read_unlock(); | |
f63ee72e | 1155 | |
4a30debf ON |
1156 | if (!ret && sig) |
1157 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1158 | |
1159 | return ret; | |
1160 | } | |
1161 | ||
1162 | /* | |
146a505d | 1163 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1164 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1165 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1166 | */ |
c4b92fc1 | 1167 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1168 | { |
1169 | struct task_struct *p = NULL; | |
1170 | int retval, success; | |
1171 | ||
1da177e4 LT |
1172 | success = 0; |
1173 | retval = -ESRCH; | |
c4b92fc1 | 1174 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1175 | int err = group_send_sig_info(sig, info, p); |
1176 | success |= !err; | |
1177 | retval = err; | |
c4b92fc1 | 1178 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1179 | return success ? 0 : retval; |
1180 | } | |
1181 | ||
c4b92fc1 | 1182 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1183 | { |
d36174bc | 1184 | int error = -ESRCH; |
1da177e4 LT |
1185 | struct task_struct *p; |
1186 | ||
e56d0903 | 1187 | rcu_read_lock(); |
d36174bc | 1188 | retry: |
c4b92fc1 | 1189 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1190 | if (p) { |
1da177e4 | 1191 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1192 | if (unlikely(error == -ESRCH)) |
1193 | /* | |
1194 | * The task was unhashed in between, try again. | |
1195 | * If it is dead, pid_task() will return NULL, | |
1196 | * if we race with de_thread() it will find the | |
1197 | * new leader. | |
1198 | */ | |
1199 | goto retry; | |
1200 | } | |
e56d0903 | 1201 | rcu_read_unlock(); |
6ca25b55 | 1202 | |
1da177e4 LT |
1203 | return error; |
1204 | } | |
1205 | ||
5aba085e | 1206 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1207 | { |
1208 | int error; | |
1209 | rcu_read_lock(); | |
b488893a | 1210 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1211 | rcu_read_unlock(); |
1212 | return error; | |
1213 | } | |
1214 | ||
2425c08b EB |
1215 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1216 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1217 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1218 | { |
1219 | int ret = -EINVAL; | |
1220 | struct task_struct *p; | |
c69e8d9c | 1221 | const struct cred *pcred; |
14d8c9f3 | 1222 | unsigned long flags; |
46113830 HW |
1223 | |
1224 | if (!valid_signal(sig)) | |
1225 | return ret; | |
1226 | ||
14d8c9f3 | 1227 | rcu_read_lock(); |
2425c08b | 1228 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1229 | if (!p) { |
1230 | ret = -ESRCH; | |
1231 | goto out_unlock; | |
1232 | } | |
c69e8d9c | 1233 | pcred = __task_cred(p); |
614c517d | 1234 | if (si_fromuser(info) && |
c69e8d9c DH |
1235 | euid != pcred->suid && euid != pcred->uid && |
1236 | uid != pcred->suid && uid != pcred->uid) { | |
46113830 HW |
1237 | ret = -EPERM; |
1238 | goto out_unlock; | |
1239 | } | |
8f95dc58 DQ |
1240 | ret = security_task_kill(p, info, sig, secid); |
1241 | if (ret) | |
1242 | goto out_unlock; | |
14d8c9f3 TG |
1243 | |
1244 | if (sig) { | |
1245 | if (lock_task_sighand(p, &flags)) { | |
1246 | ret = __send_signal(sig, info, p, 1, 0); | |
1247 | unlock_task_sighand(p, &flags); | |
1248 | } else | |
1249 | ret = -ESRCH; | |
46113830 HW |
1250 | } |
1251 | out_unlock: | |
14d8c9f3 | 1252 | rcu_read_unlock(); |
46113830 HW |
1253 | return ret; |
1254 | } | |
2425c08b | 1255 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1256 | |
1257 | /* | |
1258 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1259 | * | |
1260 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1261 | * is probably wrong. Should make it like BSD or SYSV. | |
1262 | */ | |
1263 | ||
bc64efd2 | 1264 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1265 | { |
8d42db18 | 1266 | int ret; |
d5df763b PE |
1267 | |
1268 | if (pid > 0) { | |
1269 | rcu_read_lock(); | |
1270 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1271 | rcu_read_unlock(); | |
1272 | return ret; | |
1273 | } | |
1274 | ||
1275 | read_lock(&tasklist_lock); | |
1276 | if (pid != -1) { | |
1277 | ret = __kill_pgrp_info(sig, info, | |
1278 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1279 | } else { | |
1da177e4 LT |
1280 | int retval = 0, count = 0; |
1281 | struct task_struct * p; | |
1282 | ||
1da177e4 | 1283 | for_each_process(p) { |
d25141a8 SB |
1284 | if (task_pid_vnr(p) > 1 && |
1285 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1286 | int err = group_send_sig_info(sig, info, p); |
1287 | ++count; | |
1288 | if (err != -EPERM) | |
1289 | retval = err; | |
1290 | } | |
1291 | } | |
8d42db18 | 1292 | ret = count ? retval : -ESRCH; |
1da177e4 | 1293 | } |
d5df763b PE |
1294 | read_unlock(&tasklist_lock); |
1295 | ||
8d42db18 | 1296 | return ret; |
1da177e4 LT |
1297 | } |
1298 | ||
1299 | /* | |
1300 | * These are for backward compatibility with the rest of the kernel source. | |
1301 | */ | |
1302 | ||
5aba085e | 1303 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 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 | |
5aba085e | 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 | 1555 | /* |
5aba085e | 1556 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
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 | 1613 | /* |
5aba085e | 1614 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
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. | |
5aba085e | 1738 | * Returns non-zero if we've actually stopped and released the siglock. |
1da177e4 LT |
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 | ||
5aba085e RD |
1826 | /* |
1827 | * Update the siginfo structure if the signal has | |
1828 | * changed. If the debugger wanted something | |
1829 | * specific in the siginfo structure then it should | |
1830 | * have updated *info via PTRACE_SETSIGINFO. | |
1831 | */ | |
18c98b65 RM |
1832 | if (signr != info->si_signo) { |
1833 | info->si_signo = signr; | |
1834 | info->si_errno = 0; | |
1835 | info->si_code = SI_USER; | |
1836 | info->si_pid = task_pid_vnr(current->parent); | |
c69e8d9c | 1837 | info->si_uid = task_uid(current->parent); |
18c98b65 RM |
1838 | } |
1839 | ||
1840 | /* If the (new) signal is now blocked, requeue it. */ | |
1841 | if (sigismember(¤t->blocked, signr)) { | |
1842 | specific_send_sig_info(signr, info, current); | |
1843 | signr = 0; | |
1844 | } | |
1845 | ||
1846 | return signr; | |
1847 | } | |
1848 | ||
1da177e4 LT |
1849 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
1850 | struct pt_regs *regs, void *cookie) | |
1851 | { | |
f6b76d4f ON |
1852 | struct sighand_struct *sighand = current->sighand; |
1853 | struct signal_struct *signal = current->signal; | |
1854 | int signr; | |
1da177e4 | 1855 | |
13b1c3d4 RM |
1856 | relock: |
1857 | /* | |
1858 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
1859 | * While in TASK_STOPPED, we were considered "frozen enough". | |
1860 | * Now that we woke up, it's crucial if we're supposed to be | |
1861 | * frozen that we freeze now before running anything substantial. | |
1862 | */ | |
fc558a74 RW |
1863 | try_to_freeze(); |
1864 | ||
f6b76d4f | 1865 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
1866 | /* |
1867 | * Every stopped thread goes here after wakeup. Check to see if | |
1868 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
1869 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
1870 | */ | |
f6b76d4f ON |
1871 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
1872 | int why = (signal->flags & SIGNAL_STOP_CONTINUED) | |
e4420551 | 1873 | ? CLD_CONTINUED : CLD_STOPPED; |
f6b76d4f | 1874 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 1875 | |
ae6d2ed7 RM |
1876 | why = tracehook_notify_jctl(why, CLD_CONTINUED); |
1877 | spin_unlock_irq(&sighand->siglock); | |
fa00b80b | 1878 | |
ae6d2ed7 RM |
1879 | if (why) { |
1880 | read_lock(&tasklist_lock); | |
1881 | do_notify_parent_cldstop(current->group_leader, why); | |
1882 | read_unlock(&tasklist_lock); | |
1883 | } | |
e4420551 ON |
1884 | goto relock; |
1885 | } | |
1886 | ||
1da177e4 LT |
1887 | for (;;) { |
1888 | struct k_sigaction *ka; | |
7bcf6a2c | 1889 | /* |
25985edc | 1890 | * Tracing can induce an artificial signal and choose sigaction. |
7bcf6a2c RM |
1891 | * The return value in @signr determines the default action, |
1892 | * but @info->si_signo is the signal number we will report. | |
1893 | */ | |
1894 | signr = tracehook_get_signal(current, regs, info, return_ka); | |
1895 | if (unlikely(signr < 0)) | |
1896 | goto relock; | |
1897 | if (unlikely(signr != 0)) | |
1898 | ka = return_ka; | |
1899 | else { | |
1be53963 ON |
1900 | if (unlikely(signal->group_stop_count > 0) && |
1901 | do_signal_stop(0)) | |
1902 | goto relock; | |
1903 | ||
7bcf6a2c RM |
1904 | signr = dequeue_signal(current, ¤t->blocked, |
1905 | info); | |
1da177e4 | 1906 | |
18c98b65 | 1907 | if (!signr) |
7bcf6a2c RM |
1908 | break; /* will return 0 */ |
1909 | ||
1910 | if (signr != SIGKILL) { | |
1911 | signr = ptrace_signal(signr, info, | |
1912 | regs, cookie); | |
1913 | if (!signr) | |
1914 | continue; | |
1915 | } | |
1916 | ||
1917 | ka = &sighand->action[signr-1]; | |
1da177e4 LT |
1918 | } |
1919 | ||
f9d4257e MH |
1920 | /* Trace actually delivered signals. */ |
1921 | trace_signal_deliver(signr, info, ka); | |
1922 | ||
1da177e4 LT |
1923 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
1924 | continue; | |
1925 | if (ka->sa.sa_handler != SIG_DFL) { | |
1926 | /* Run the handler. */ | |
1927 | *return_ka = *ka; | |
1928 | ||
1929 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1930 | ka->sa.sa_handler = SIG_DFL; | |
1931 | ||
1932 | break; /* will return non-zero "signr" value */ | |
1933 | } | |
1934 | ||
1935 | /* | |
1936 | * Now we are doing the default action for this signal. | |
1937 | */ | |
1938 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1939 | continue; | |
1940 | ||
84d73786 | 1941 | /* |
0fbc26a6 | 1942 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
1943 | * Container-init gets no signals it doesn't want from same |
1944 | * container. | |
1945 | * | |
1946 | * Note that if global/container-init sees a sig_kernel_only() | |
1947 | * signal here, the signal must have been generated internally | |
1948 | * or must have come from an ancestor namespace. In either | |
1949 | * case, the signal cannot be dropped. | |
84d73786 | 1950 | */ |
fae5fa44 | 1951 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 1952 | !sig_kernel_only(signr)) |
1da177e4 LT |
1953 | continue; |
1954 | ||
1955 | if (sig_kernel_stop(signr)) { | |
1956 | /* | |
1957 | * The default action is to stop all threads in | |
1958 | * the thread group. The job control signals | |
1959 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1960 | * always works. Note that siglock needs to be | |
1961 | * dropped during the call to is_orphaned_pgrp() | |
1962 | * because of lock ordering with tasklist_lock. | |
1963 | * This allows an intervening SIGCONT to be posted. | |
1964 | * We need to check for that and bail out if necessary. | |
1965 | */ | |
1966 | if (signr != SIGSTOP) { | |
f6b76d4f | 1967 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1968 | |
1969 | /* signals can be posted during this window */ | |
1970 | ||
3e7cd6c4 | 1971 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
1972 | goto relock; |
1973 | ||
f6b76d4f | 1974 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
1975 | } |
1976 | ||
7bcf6a2c | 1977 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
1978 | /* It released the siglock. */ |
1979 | goto relock; | |
1980 | } | |
1981 | ||
1982 | /* | |
1983 | * We didn't actually stop, due to a race | |
1984 | * with SIGCONT or something like that. | |
1985 | */ | |
1986 | continue; | |
1987 | } | |
1988 | ||
f6b76d4f | 1989 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
1990 | |
1991 | /* | |
1992 | * Anything else is fatal, maybe with a core dump. | |
1993 | */ | |
1994 | current->flags |= PF_SIGNALED; | |
2dce81bf | 1995 | |
1da177e4 | 1996 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 1997 | if (print_fatal_signals) |
7bcf6a2c | 1998 | print_fatal_signal(regs, info->si_signo); |
1da177e4 LT |
1999 | /* |
2000 | * If it was able to dump core, this kills all | |
2001 | * other threads in the group and synchronizes with | |
2002 | * their demise. If we lost the race with another | |
2003 | * thread getting here, it set group_exit_code | |
2004 | * first and our do_group_exit call below will use | |
2005 | * that value and ignore the one we pass it. | |
2006 | */ | |
7bcf6a2c | 2007 | do_coredump(info->si_signo, info->si_signo, regs); |
1da177e4 LT |
2008 | } |
2009 | ||
2010 | /* | |
2011 | * Death signals, no core dump. | |
2012 | */ | |
7bcf6a2c | 2013 | do_group_exit(info->si_signo); |
1da177e4 LT |
2014 | /* NOTREACHED */ |
2015 | } | |
f6b76d4f | 2016 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2017 | return signr; |
2018 | } | |
2019 | ||
d12619b5 ON |
2020 | void exit_signals(struct task_struct *tsk) |
2021 | { | |
2022 | int group_stop = 0; | |
5dee1707 | 2023 | struct task_struct *t; |
d12619b5 | 2024 | |
5dee1707 ON |
2025 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2026 | tsk->flags |= PF_EXITING; | |
2027 | return; | |
d12619b5 ON |
2028 | } |
2029 | ||
5dee1707 | 2030 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2031 | /* |
2032 | * From now this task is not visible for group-wide signals, | |
2033 | * see wants_signal(), do_signal_stop(). | |
2034 | */ | |
2035 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
2036 | if (!signal_pending(tsk)) |
2037 | goto out; | |
2038 | ||
5aba085e RD |
2039 | /* |
2040 | * It could be that __group_complete_signal() choose us to | |
5dee1707 ON |
2041 | * notify about group-wide signal. Another thread should be |
2042 | * woken now to take the signal since we will not. | |
2043 | */ | |
2044 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
2045 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
2046 | recalc_sigpending_and_wake(t); | |
2047 | ||
2048 | if (unlikely(tsk->signal->group_stop_count) && | |
2049 | !--tsk->signal->group_stop_count) { | |
2050 | tsk->signal->flags = SIGNAL_STOP_STOPPED; | |
ae6d2ed7 | 2051 | group_stop = tracehook_notify_jctl(CLD_STOPPED, CLD_STOPPED); |
5dee1707 ON |
2052 | } |
2053 | out: | |
d12619b5 ON |
2054 | spin_unlock_irq(&tsk->sighand->siglock); |
2055 | ||
ae6d2ed7 | 2056 | if (unlikely(group_stop)) { |
d12619b5 | 2057 | read_lock(&tasklist_lock); |
ae6d2ed7 | 2058 | do_notify_parent_cldstop(tsk, group_stop); |
d12619b5 ON |
2059 | read_unlock(&tasklist_lock); |
2060 | } | |
2061 | } | |
2062 | ||
1da177e4 LT |
2063 | EXPORT_SYMBOL(recalc_sigpending); |
2064 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2065 | EXPORT_SYMBOL(flush_signals); | |
2066 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2067 | EXPORT_SYMBOL(send_sig); |
2068 | EXPORT_SYMBOL(send_sig_info); | |
2069 | EXPORT_SYMBOL(sigprocmask); | |
2070 | EXPORT_SYMBOL(block_all_signals); | |
2071 | EXPORT_SYMBOL(unblock_all_signals); | |
2072 | ||
2073 | ||
2074 | /* | |
2075 | * System call entry points. | |
2076 | */ | |
2077 | ||
41c57892 RD |
2078 | /** |
2079 | * sys_restart_syscall - restart a system call | |
2080 | */ | |
754fe8d2 | 2081 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2082 | { |
2083 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2084 | return restart->fn(restart); | |
2085 | } | |
2086 | ||
2087 | long do_no_restart_syscall(struct restart_block *param) | |
2088 | { | |
2089 | return -EINTR; | |
2090 | } | |
2091 | ||
2092 | /* | |
2093 | * We don't need to get the kernel lock - this is all local to this | |
2094 | * particular thread.. (and that's good, because this is _heavily_ | |
2095 | * used by various programs) | |
2096 | */ | |
2097 | ||
2098 | /* | |
2099 | * This is also useful for kernel threads that want to temporarily | |
2100 | * (or permanently) block certain signals. | |
2101 | * | |
2102 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2103 | * interface happily blocks "unblockable" signals like SIGKILL | |
2104 | * and friends. | |
2105 | */ | |
2106 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2107 | { | |
2108 | int error; | |
1da177e4 LT |
2109 | |
2110 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
2111 | if (oldset) |
2112 | *oldset = current->blocked; | |
2113 | ||
1da177e4 LT |
2114 | error = 0; |
2115 | switch (how) { | |
2116 | case SIG_BLOCK: | |
2117 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2118 | break; | |
2119 | case SIG_UNBLOCK: | |
2120 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2121 | break; | |
2122 | case SIG_SETMASK: | |
2123 | current->blocked = *set; | |
2124 | break; | |
2125 | default: | |
2126 | error = -EINVAL; | |
2127 | } | |
2128 | recalc_sigpending(); | |
2129 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 2130 | |
1da177e4 LT |
2131 | return error; |
2132 | } | |
2133 | ||
41c57892 RD |
2134 | /** |
2135 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2136 | * @how: whether to add, remove, or set signals | |
2137 | * @set: stores pending signals | |
2138 | * @oset: previous value of signal mask if non-null | |
2139 | * @sigsetsize: size of sigset_t type | |
2140 | */ | |
17da2bd9 HC |
2141 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set, |
2142 | sigset_t __user *, oset, size_t, sigsetsize) | |
1da177e4 LT |
2143 | { |
2144 | int error = -EINVAL; | |
2145 | sigset_t old_set, new_set; | |
2146 | ||
2147 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2148 | if (sigsetsize != sizeof(sigset_t)) | |
2149 | goto out; | |
2150 | ||
2151 | if (set) { | |
2152 | error = -EFAULT; | |
2153 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2154 | goto out; | |
2155 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2156 | ||
2157 | error = sigprocmask(how, &new_set, &old_set); | |
2158 | if (error) | |
2159 | goto out; | |
2160 | if (oset) | |
2161 | goto set_old; | |
2162 | } else if (oset) { | |
2163 | spin_lock_irq(¤t->sighand->siglock); | |
2164 | old_set = current->blocked; | |
2165 | spin_unlock_irq(¤t->sighand->siglock); | |
2166 | ||
2167 | set_old: | |
2168 | error = -EFAULT; | |
2169 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2170 | goto out; | |
2171 | } | |
2172 | error = 0; | |
2173 | out: | |
2174 | return error; | |
2175 | } | |
2176 | ||
2177 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2178 | { | |
2179 | long error = -EINVAL; | |
2180 | sigset_t pending; | |
2181 | ||
2182 | if (sigsetsize > sizeof(sigset_t)) | |
2183 | goto out; | |
2184 | ||
2185 | spin_lock_irq(¤t->sighand->siglock); | |
2186 | sigorsets(&pending, ¤t->pending.signal, | |
2187 | ¤t->signal->shared_pending.signal); | |
2188 | spin_unlock_irq(¤t->sighand->siglock); | |
2189 | ||
2190 | /* Outside the lock because only this thread touches it. */ | |
2191 | sigandsets(&pending, ¤t->blocked, &pending); | |
2192 | ||
2193 | error = -EFAULT; | |
2194 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2195 | error = 0; | |
2196 | ||
2197 | out: | |
2198 | return error; | |
5aba085e | 2199 | } |
1da177e4 | 2200 | |
41c57892 RD |
2201 | /** |
2202 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2203 | * while blocked | |
2204 | * @set: stores pending signals | |
2205 | * @sigsetsize: size of sigset_t type or larger | |
2206 | */ | |
17da2bd9 | 2207 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize) |
1da177e4 LT |
2208 | { |
2209 | return do_sigpending(set, sigsetsize); | |
2210 | } | |
2211 | ||
2212 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2213 | ||
2214 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2215 | { | |
2216 | int err; | |
2217 | ||
2218 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2219 | return -EFAULT; | |
2220 | if (from->si_code < 0) | |
2221 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2222 | ? -EFAULT : 0; | |
2223 | /* | |
2224 | * If you change siginfo_t structure, please be sure | |
2225 | * this code is fixed accordingly. | |
fba2afaa DL |
2226 | * Please remember to update the signalfd_copyinfo() function |
2227 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2228 | * It should never copy any pad contained in the structure |
2229 | * to avoid security leaks, but must copy the generic | |
2230 | * 3 ints plus the relevant union member. | |
2231 | */ | |
2232 | err = __put_user(from->si_signo, &to->si_signo); | |
2233 | err |= __put_user(from->si_errno, &to->si_errno); | |
2234 | err |= __put_user((short)from->si_code, &to->si_code); | |
2235 | switch (from->si_code & __SI_MASK) { | |
2236 | case __SI_KILL: | |
2237 | err |= __put_user(from->si_pid, &to->si_pid); | |
2238 | err |= __put_user(from->si_uid, &to->si_uid); | |
2239 | break; | |
2240 | case __SI_TIMER: | |
2241 | err |= __put_user(from->si_tid, &to->si_tid); | |
2242 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2243 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2244 | break; | |
2245 | case __SI_POLL: | |
2246 | err |= __put_user(from->si_band, &to->si_band); | |
2247 | err |= __put_user(from->si_fd, &to->si_fd); | |
2248 | break; | |
2249 | case __SI_FAULT: | |
2250 | err |= __put_user(from->si_addr, &to->si_addr); | |
2251 | #ifdef __ARCH_SI_TRAPNO | |
2252 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2253 | #endif |
2254 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2255 | /* |
a337fdac | 2256 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2257 | * so check explicitly for the right codes here. |
a337fdac AK |
2258 | */ |
2259 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2260 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2261 | #endif |
2262 | break; | |
2263 | case __SI_CHLD: | |
2264 | err |= __put_user(from->si_pid, &to->si_pid); | |
2265 | err |= __put_user(from->si_uid, &to->si_uid); | |
2266 | err |= __put_user(from->si_status, &to->si_status); | |
2267 | err |= __put_user(from->si_utime, &to->si_utime); | |
2268 | err |= __put_user(from->si_stime, &to->si_stime); | |
2269 | break; | |
2270 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2271 | case __SI_MESGQ: /* But this is */ | |
2272 | err |= __put_user(from->si_pid, &to->si_pid); | |
2273 | err |= __put_user(from->si_uid, &to->si_uid); | |
2274 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2275 | break; | |
2276 | default: /* this is just in case for now ... */ | |
2277 | err |= __put_user(from->si_pid, &to->si_pid); | |
2278 | err |= __put_user(from->si_uid, &to->si_uid); | |
2279 | break; | |
2280 | } | |
2281 | return err; | |
2282 | } | |
2283 | ||
2284 | #endif | |
2285 | ||
41c57892 RD |
2286 | /** |
2287 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2288 | * in @uthese | |
2289 | * @uthese: queued signals to wait for | |
2290 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2291 | * @uts: upper bound on process time suspension | |
2292 | * @sigsetsize: size of sigset_t type | |
2293 | */ | |
17da2bd9 HC |
2294 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2295 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2296 | size_t, sigsetsize) | |
1da177e4 LT |
2297 | { |
2298 | int ret, sig; | |
2299 | sigset_t these; | |
2300 | struct timespec ts; | |
2301 | siginfo_t info; | |
2302 | long timeout = 0; | |
2303 | ||
2304 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2305 | if (sigsetsize != sizeof(sigset_t)) | |
2306 | return -EINVAL; | |
2307 | ||
2308 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2309 | return -EFAULT; | |
5aba085e | 2310 | |
1da177e4 LT |
2311 | /* |
2312 | * Invert the set of allowed signals to get those we | |
2313 | * want to block. | |
2314 | */ | |
2315 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2316 | signotset(&these); | |
2317 | ||
2318 | if (uts) { | |
2319 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2320 | return -EFAULT; | |
2321 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2322 | || ts.tv_sec < 0) | |
2323 | return -EINVAL; | |
2324 | } | |
2325 | ||
2326 | spin_lock_irq(¤t->sighand->siglock); | |
2327 | sig = dequeue_signal(current, &these, &info); | |
2328 | if (!sig) { | |
2329 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2330 | if (uts) | |
2331 | timeout = (timespec_to_jiffies(&ts) | |
2332 | + (ts.tv_sec || ts.tv_nsec)); | |
2333 | ||
2334 | if (timeout) { | |
5aba085e RD |
2335 | /* |
2336 | * None ready -- temporarily unblock those we're | |
1da177e4 | 2337 | * interested while we are sleeping in so that we'll |
5aba085e RD |
2338 | * be awakened when they arrive. |
2339 | */ | |
1da177e4 LT |
2340 | current->real_blocked = current->blocked; |
2341 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2342 | recalc_sigpending(); | |
2343 | spin_unlock_irq(¤t->sighand->siglock); | |
2344 | ||
75bcc8c5 | 2345 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2346 | |
1da177e4 LT |
2347 | spin_lock_irq(¤t->sighand->siglock); |
2348 | sig = dequeue_signal(current, &these, &info); | |
2349 | current->blocked = current->real_blocked; | |
2350 | siginitset(¤t->real_blocked, 0); | |
2351 | recalc_sigpending(); | |
2352 | } | |
2353 | } | |
2354 | spin_unlock_irq(¤t->sighand->siglock); | |
2355 | ||
2356 | if (sig) { | |
2357 | ret = sig; | |
2358 | if (uinfo) { | |
2359 | if (copy_siginfo_to_user(uinfo, &info)) | |
2360 | ret = -EFAULT; | |
2361 | } | |
2362 | } else { | |
2363 | ret = -EAGAIN; | |
2364 | if (timeout) | |
2365 | ret = -EINTR; | |
2366 | } | |
2367 | ||
2368 | return ret; | |
2369 | } | |
2370 | ||
41c57892 RD |
2371 | /** |
2372 | * sys_kill - send a signal to a process | |
2373 | * @pid: the PID of the process | |
2374 | * @sig: signal to be sent | |
2375 | */ | |
17da2bd9 | 2376 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2377 | { |
2378 | struct siginfo info; | |
2379 | ||
2380 | info.si_signo = sig; | |
2381 | info.si_errno = 0; | |
2382 | info.si_code = SI_USER; | |
b488893a | 2383 | info.si_pid = task_tgid_vnr(current); |
76aac0e9 | 2384 | info.si_uid = current_uid(); |
1da177e4 LT |
2385 | |
2386 | return kill_something_info(sig, &info, pid); | |
2387 | } | |
2388 | ||
30b4ae8a TG |
2389 | static int |
2390 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2391 | { |
1da177e4 | 2392 | struct task_struct *p; |
30b4ae8a | 2393 | int error = -ESRCH; |
1da177e4 | 2394 | |
3547ff3a | 2395 | rcu_read_lock(); |
228ebcbe | 2396 | p = find_task_by_vpid(pid); |
b488893a | 2397 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2398 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2399 | /* |
2400 | * The null signal is a permissions and process existence | |
2401 | * probe. No signal is actually delivered. | |
2402 | */ | |
4a30debf ON |
2403 | if (!error && sig) { |
2404 | error = do_send_sig_info(sig, info, p, false); | |
2405 | /* | |
2406 | * If lock_task_sighand() failed we pretend the task | |
2407 | * dies after receiving the signal. The window is tiny, | |
2408 | * and the signal is private anyway. | |
2409 | */ | |
2410 | if (unlikely(error == -ESRCH)) | |
2411 | error = 0; | |
1da177e4 LT |
2412 | } |
2413 | } | |
3547ff3a | 2414 | rcu_read_unlock(); |
6dd69f10 | 2415 | |
1da177e4 LT |
2416 | return error; |
2417 | } | |
2418 | ||
30b4ae8a TG |
2419 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2420 | { | |
2421 | struct siginfo info; | |
2422 | ||
2423 | info.si_signo = sig; | |
2424 | info.si_errno = 0; | |
2425 | info.si_code = SI_TKILL; | |
2426 | info.si_pid = task_tgid_vnr(current); | |
2427 | info.si_uid = current_uid(); | |
2428 | ||
2429 | return do_send_specific(tgid, pid, sig, &info); | |
2430 | } | |
2431 | ||
6dd69f10 VL |
2432 | /** |
2433 | * sys_tgkill - send signal to one specific thread | |
2434 | * @tgid: the thread group ID of the thread | |
2435 | * @pid: the PID of the thread | |
2436 | * @sig: signal to be sent | |
2437 | * | |
72fd4a35 | 2438 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2439 | * exists but it's not belonging to the target process anymore. This |
2440 | * method solves the problem of threads exiting and PIDs getting reused. | |
2441 | */ | |
a5f8fa9e | 2442 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2443 | { |
2444 | /* This is only valid for single tasks */ | |
2445 | if (pid <= 0 || tgid <= 0) | |
2446 | return -EINVAL; | |
2447 | ||
2448 | return do_tkill(tgid, pid, sig); | |
2449 | } | |
2450 | ||
41c57892 RD |
2451 | /** |
2452 | * sys_tkill - send signal to one specific task | |
2453 | * @pid: the PID of the task | |
2454 | * @sig: signal to be sent | |
2455 | * | |
1da177e4 LT |
2456 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2457 | */ | |
a5f8fa9e | 2458 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2459 | { |
1da177e4 LT |
2460 | /* This is only valid for single tasks */ |
2461 | if (pid <= 0) | |
2462 | return -EINVAL; | |
2463 | ||
6dd69f10 | 2464 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2465 | } |
2466 | ||
41c57892 RD |
2467 | /** |
2468 | * sys_rt_sigqueueinfo - send signal information to a signal | |
2469 | * @pid: the PID of the thread | |
2470 | * @sig: signal to be sent | |
2471 | * @uinfo: signal info to be sent | |
2472 | */ | |
a5f8fa9e HC |
2473 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2474 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2475 | { |
2476 | siginfo_t info; | |
2477 | ||
2478 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2479 | return -EFAULT; | |
2480 | ||
2481 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2482 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2483 | */ | |
243b422a | 2484 | if (info.si_code >= 0 || info.si_code == SI_TKILL) { |
da48524e JT |
2485 | /* We used to allow any < 0 si_code */ |
2486 | WARN_ON_ONCE(info.si_code < 0); | |
1da177e4 | 2487 | return -EPERM; |
da48524e | 2488 | } |
1da177e4 LT |
2489 | info.si_signo = sig; |
2490 | ||
2491 | /* POSIX.1b doesn't mention process groups. */ | |
2492 | return kill_proc_info(sig, &info, pid); | |
2493 | } | |
2494 | ||
62ab4505 TG |
2495 | long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
2496 | { | |
2497 | /* This is only valid for single tasks */ | |
2498 | if (pid <= 0 || tgid <= 0) | |
2499 | return -EINVAL; | |
2500 | ||
2501 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2502 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2503 | */ | |
243b422a | 2504 | if (info->si_code >= 0 || info->si_code == SI_TKILL) { |
da48524e JT |
2505 | /* We used to allow any < 0 si_code */ |
2506 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 2507 | return -EPERM; |
da48524e | 2508 | } |
62ab4505 TG |
2509 | info->si_signo = sig; |
2510 | ||
2511 | return do_send_specific(tgid, pid, sig, info); | |
2512 | } | |
2513 | ||
2514 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
2515 | siginfo_t __user *, uinfo) | |
2516 | { | |
2517 | siginfo_t info; | |
2518 | ||
2519 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2520 | return -EFAULT; | |
2521 | ||
2522 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
2523 | } | |
2524 | ||
88531f72 | 2525 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 2526 | { |
93585eea | 2527 | struct task_struct *t = current; |
1da177e4 | 2528 | struct k_sigaction *k; |
71fabd5e | 2529 | sigset_t mask; |
1da177e4 | 2530 | |
7ed20e1a | 2531 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2532 | return -EINVAL; |
2533 | ||
93585eea | 2534 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
2535 | |
2536 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2537 | if (oact) |
2538 | *oact = *k; | |
2539 | ||
2540 | if (act) { | |
9ac95f2f ON |
2541 | sigdelsetmask(&act->sa.sa_mask, |
2542 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2543 | *k = *act; |
1da177e4 LT |
2544 | /* |
2545 | * POSIX 3.3.1.3: | |
2546 | * "Setting a signal action to SIG_IGN for a signal that is | |
2547 | * pending shall cause the pending signal to be discarded, | |
2548 | * whether or not it is blocked." | |
2549 | * | |
2550 | * "Setting a signal action to SIG_DFL for a signal that is | |
2551 | * pending and whose default action is to ignore the signal | |
2552 | * (for example, SIGCHLD), shall cause the pending signal to | |
2553 | * be discarded, whether or not it is blocked" | |
2554 | */ | |
35de254d | 2555 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
2556 | sigemptyset(&mask); |
2557 | sigaddset(&mask, sig); | |
2558 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2559 | do { |
71fabd5e | 2560 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2561 | t = next_thread(t); |
2562 | } while (t != current); | |
1da177e4 | 2563 | } |
1da177e4 LT |
2564 | } |
2565 | ||
2566 | spin_unlock_irq(¤t->sighand->siglock); | |
2567 | return 0; | |
2568 | } | |
2569 | ||
2570 | int | |
2571 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2572 | { | |
2573 | stack_t oss; | |
2574 | int error; | |
2575 | ||
0083fc2c LT |
2576 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
2577 | oss.ss_size = current->sas_ss_size; | |
2578 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
2579 | |
2580 | if (uss) { | |
2581 | void __user *ss_sp; | |
2582 | size_t ss_size; | |
2583 | int ss_flags; | |
2584 | ||
2585 | error = -EFAULT; | |
0dd8486b LT |
2586 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
2587 | goto out; | |
2588 | error = __get_user(ss_sp, &uss->ss_sp) | | |
2589 | __get_user(ss_flags, &uss->ss_flags) | | |
2590 | __get_user(ss_size, &uss->ss_size); | |
2591 | if (error) | |
1da177e4 LT |
2592 | goto out; |
2593 | ||
2594 | error = -EPERM; | |
2595 | if (on_sig_stack(sp)) | |
2596 | goto out; | |
2597 | ||
2598 | error = -EINVAL; | |
2599 | /* | |
5aba085e | 2600 | * Note - this code used to test ss_flags incorrectly: |
1da177e4 LT |
2601 | * old code may have been written using ss_flags==0 |
2602 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2603 | * way that worked) - this fix preserves that older | |
5aba085e | 2604 | * mechanism. |
1da177e4 LT |
2605 | */ |
2606 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2607 | goto out; | |
2608 | ||
2609 | if (ss_flags == SS_DISABLE) { | |
2610 | ss_size = 0; | |
2611 | ss_sp = NULL; | |
2612 | } else { | |
2613 | error = -ENOMEM; | |
2614 | if (ss_size < MINSIGSTKSZ) | |
2615 | goto out; | |
2616 | } | |
2617 | ||
2618 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2619 | current->sas_ss_size = ss_size; | |
2620 | } | |
2621 | ||
0083fc2c | 2622 | error = 0; |
1da177e4 LT |
2623 | if (uoss) { |
2624 | error = -EFAULT; | |
0083fc2c | 2625 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 2626 | goto out; |
0083fc2c LT |
2627 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
2628 | __put_user(oss.ss_size, &uoss->ss_size) | | |
2629 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
2630 | } |
2631 | ||
1da177e4 LT |
2632 | out: |
2633 | return error; | |
2634 | } | |
2635 | ||
2636 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2637 | ||
41c57892 RD |
2638 | /** |
2639 | * sys_sigpending - examine pending signals | |
2640 | * @set: where mask of pending signal is returned | |
2641 | */ | |
b290ebe2 | 2642 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 LT |
2643 | { |
2644 | return do_sigpending(set, sizeof(*set)); | |
2645 | } | |
2646 | ||
2647 | #endif | |
2648 | ||
2649 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
2650 | /** |
2651 | * sys_sigprocmask - examine and change blocked signals | |
2652 | * @how: whether to add, remove, or set signals | |
2653 | * @set: signals to add or remove (if non-null) | |
2654 | * @oset: previous value of signal mask if non-null | |
2655 | * | |
5aba085e RD |
2656 | * Some platforms have their own version with special arguments; |
2657 | * others support only sys_rt_sigprocmask. | |
2658 | */ | |
1da177e4 | 2659 | |
b290ebe2 HC |
2660 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set, |
2661 | old_sigset_t __user *, oset) | |
1da177e4 LT |
2662 | { |
2663 | int error; | |
2664 | old_sigset_t old_set, new_set; | |
2665 | ||
2666 | if (set) { | |
2667 | error = -EFAULT; | |
2668 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2669 | goto out; | |
2670 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2671 | ||
2672 | spin_lock_irq(¤t->sighand->siglock); | |
2673 | old_set = current->blocked.sig[0]; | |
2674 | ||
2675 | error = 0; | |
2676 | switch (how) { | |
2677 | default: | |
2678 | error = -EINVAL; | |
2679 | break; | |
2680 | case SIG_BLOCK: | |
2681 | sigaddsetmask(¤t->blocked, new_set); | |
2682 | break; | |
2683 | case SIG_UNBLOCK: | |
2684 | sigdelsetmask(¤t->blocked, new_set); | |
2685 | break; | |
2686 | case SIG_SETMASK: | |
2687 | current->blocked.sig[0] = new_set; | |
2688 | break; | |
2689 | } | |
2690 | ||
2691 | recalc_sigpending(); | |
2692 | spin_unlock_irq(¤t->sighand->siglock); | |
2693 | if (error) | |
2694 | goto out; | |
2695 | if (oset) | |
2696 | goto set_old; | |
2697 | } else if (oset) { | |
2698 | old_set = current->blocked.sig[0]; | |
2699 | set_old: | |
2700 | error = -EFAULT; | |
2701 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2702 | goto out; | |
2703 | } | |
2704 | error = 0; | |
2705 | out: | |
2706 | return error; | |
2707 | } | |
2708 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2709 | ||
2710 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
41c57892 RD |
2711 | /** |
2712 | * sys_rt_sigaction - alter an action taken by a process | |
2713 | * @sig: signal to be sent | |
f9fa0bc1 RD |
2714 | * @act: new sigaction |
2715 | * @oact: used to save the previous sigaction | |
41c57892 RD |
2716 | * @sigsetsize: size of sigset_t type |
2717 | */ | |
d4e82042 HC |
2718 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
2719 | const struct sigaction __user *, act, | |
2720 | struct sigaction __user *, oact, | |
2721 | size_t, sigsetsize) | |
1da177e4 LT |
2722 | { |
2723 | struct k_sigaction new_sa, old_sa; | |
2724 | int ret = -EINVAL; | |
2725 | ||
2726 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2727 | if (sigsetsize != sizeof(sigset_t)) | |
2728 | goto out; | |
2729 | ||
2730 | if (act) { | |
2731 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2732 | return -EFAULT; | |
2733 | } | |
2734 | ||
2735 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2736 | ||
2737 | if (!ret && oact) { | |
2738 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2739 | return -EFAULT; | |
2740 | } | |
2741 | out: | |
2742 | return ret; | |
2743 | } | |
2744 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2745 | ||
2746 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2747 | ||
2748 | /* | |
2749 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2750 | */ | |
a5f8fa9e | 2751 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
2752 | { |
2753 | /* SMP safe */ | |
2754 | return current->blocked.sig[0]; | |
2755 | } | |
2756 | ||
a5f8fa9e | 2757 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 LT |
2758 | { |
2759 | int old; | |
2760 | ||
2761 | spin_lock_irq(¤t->sighand->siglock); | |
2762 | old = current->blocked.sig[0]; | |
2763 | ||
2764 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2765 | sigmask(SIGSTOP))); | |
2766 | recalc_sigpending(); | |
2767 | spin_unlock_irq(¤t->sighand->siglock); | |
2768 | ||
2769 | return old; | |
2770 | } | |
2771 | #endif /* __ARCH_WANT_SGETMASK */ | |
2772 | ||
2773 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2774 | /* | |
2775 | * For backwards compatibility. Functionality superseded by sigaction. | |
2776 | */ | |
a5f8fa9e | 2777 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
2778 | { |
2779 | struct k_sigaction new_sa, old_sa; | |
2780 | int ret; | |
2781 | ||
2782 | new_sa.sa.sa_handler = handler; | |
2783 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2784 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2785 | |
2786 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2787 | ||
2788 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2789 | } | |
2790 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2791 | ||
2792 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2793 | ||
a5f8fa9e | 2794 | SYSCALL_DEFINE0(pause) |
1da177e4 LT |
2795 | { |
2796 | current->state = TASK_INTERRUPTIBLE; | |
2797 | schedule(); | |
2798 | return -ERESTARTNOHAND; | |
2799 | } | |
2800 | ||
2801 | #endif | |
2802 | ||
150256d8 | 2803 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
41c57892 RD |
2804 | /** |
2805 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
2806 | * @unewset value until a signal is received | |
2807 | * @unewset: new signal mask value | |
2808 | * @sigsetsize: size of sigset_t type | |
2809 | */ | |
d4e82042 | 2810 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
2811 | { |
2812 | sigset_t newset; | |
2813 | ||
2814 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2815 | if (sigsetsize != sizeof(sigset_t)) | |
2816 | return -EINVAL; | |
2817 | ||
2818 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2819 | return -EFAULT; | |
2820 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2821 | ||
2822 | spin_lock_irq(¤t->sighand->siglock); | |
2823 | current->saved_sigmask = current->blocked; | |
2824 | current->blocked = newset; | |
2825 | recalc_sigpending(); | |
2826 | spin_unlock_irq(¤t->sighand->siglock); | |
2827 | ||
2828 | current->state = TASK_INTERRUPTIBLE; | |
2829 | schedule(); | |
4e4c22c7 | 2830 | set_restore_sigmask(); |
150256d8 DW |
2831 | return -ERESTARTNOHAND; |
2832 | } | |
2833 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2834 | ||
f269fdd1 DH |
2835 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2836 | { | |
2837 | return NULL; | |
2838 | } | |
2839 | ||
1da177e4 LT |
2840 | void __init signals_init(void) |
2841 | { | |
0a31bd5f | 2842 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2843 | } |
67fc4e0c JW |
2844 | |
2845 | #ifdef CONFIG_KGDB_KDB | |
2846 | #include <linux/kdb.h> | |
2847 | /* | |
2848 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
2849 | * signal internals. This function checks if the required locks are | |
2850 | * available before calling the main signal code, to avoid kdb | |
2851 | * deadlocks. | |
2852 | */ | |
2853 | void | |
2854 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
2855 | { | |
2856 | static struct task_struct *kdb_prev_t; | |
2857 | int sig, new_t; | |
2858 | if (!spin_trylock(&t->sighand->siglock)) { | |
2859 | kdb_printf("Can't do kill command now.\n" | |
2860 | "The sigmask lock is held somewhere else in " | |
2861 | "kernel, try again later\n"); | |
2862 | return; | |
2863 | } | |
2864 | spin_unlock(&t->sighand->siglock); | |
2865 | new_t = kdb_prev_t != t; | |
2866 | kdb_prev_t = t; | |
2867 | if (t->state != TASK_RUNNING && new_t) { | |
2868 | kdb_printf("Process is not RUNNING, sending a signal from " | |
2869 | "kdb risks deadlock\n" | |
2870 | "on the run queue locks. " | |
2871 | "The signal has _not_ been sent.\n" | |
2872 | "Reissue the kill command if you want to risk " | |
2873 | "the deadlock.\n"); | |
2874 | return; | |
2875 | } | |
2876 | sig = info->si_signo; | |
2877 | if (send_sig_info(sig, info, t)) | |
2878 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
2879 | sig, t->pid); | |
2880 | else | |
2881 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
2882 | } | |
2883 | #endif /* CONFIG_KGDB_KDB */ |