]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 LT |
13 | #include <linux/slab.h> |
14 | #include <linux/module.h> | |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
20 | #include <linux/security.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/ptrace.h> | |
7ed20e1a | 23 | #include <linux/signal.h> |
fba2afaa | 24 | #include <linux/signalfd.h> |
f84d49b2 | 25 | #include <linux/ratelimit.h> |
35de254d | 26 | #include <linux/tracehook.h> |
c59ede7b | 27 | #include <linux/capability.h> |
7dfb7103 | 28 | #include <linux/freezer.h> |
84d73786 SB |
29 | #include <linux/pid_namespace.h> |
30 | #include <linux/nsproxy.h> | |
d1eb650f MH |
31 | #define CREATE_TRACE_POINTS |
32 | #include <trace/events/signal.h> | |
84d73786 | 33 | |
1da177e4 LT |
34 | #include <asm/param.h> |
35 | #include <asm/uaccess.h> | |
36 | #include <asm/unistd.h> | |
37 | #include <asm/siginfo.h> | |
e1396065 | 38 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
39 | |
40 | /* | |
41 | * SLAB caches for signal bits. | |
42 | */ | |
43 | ||
e18b890b | 44 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 45 | |
f84d49b2 NO |
46 | int print_fatal_signals __read_mostly; |
47 | ||
35de254d | 48 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 49 | { |
35de254d RM |
50 | return t->sighand->action[sig - 1].sa.sa_handler; |
51 | } | |
93585eea | 52 | |
35de254d RM |
53 | static int sig_handler_ignored(void __user *handler, int sig) |
54 | { | |
93585eea | 55 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
56 | return handler == SIG_IGN || |
57 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
58 | } | |
1da177e4 | 59 | |
921cf9f6 SB |
60 | static int sig_task_ignored(struct task_struct *t, int sig, |
61 | int from_ancestor_ns) | |
1da177e4 | 62 | { |
35de254d | 63 | void __user *handler; |
1da177e4 | 64 | |
f008faff ON |
65 | handler = sig_handler(t, sig); |
66 | ||
67 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
921cf9f6 | 68 | handler == SIG_DFL && !from_ancestor_ns) |
f008faff ON |
69 | return 1; |
70 | ||
71 | return sig_handler_ignored(handler, sig); | |
72 | } | |
73 | ||
921cf9f6 | 74 | static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns) |
f008faff | 75 | { |
1da177e4 LT |
76 | /* |
77 | * Blocked signals are never ignored, since the | |
78 | * signal handler may change by the time it is | |
79 | * unblocked. | |
80 | */ | |
325d22df | 81 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
82 | return 0; |
83 | ||
921cf9f6 | 84 | if (!sig_task_ignored(t, sig, from_ancestor_ns)) |
35de254d RM |
85 | return 0; |
86 | ||
87 | /* | |
88 | * Tracers may want to know about even ignored signals. | |
89 | */ | |
43918f2b | 90 | return !tracehook_consider_ignored_signal(t, sig); |
1da177e4 LT |
91 | } |
92 | ||
93 | /* | |
94 | * Re-calculate pending state from the set of locally pending | |
95 | * signals, globally pending signals, and blocked signals. | |
96 | */ | |
97 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
98 | { | |
99 | unsigned long ready; | |
100 | long i; | |
101 | ||
102 | switch (_NSIG_WORDS) { | |
103 | default: | |
104 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
105 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
106 | break; | |
107 | ||
108 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
109 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
110 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
111 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
112 | break; | |
113 | ||
114 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
115 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
116 | break; | |
117 | ||
118 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
119 | } | |
120 | return ready != 0; | |
121 | } | |
122 | ||
123 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
124 | ||
7bb44ade | 125 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 126 | { |
39efa3ef | 127 | if ((t->group_stop & GROUP_STOP_PENDING) || |
1da177e4 | 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 | ||
d79fdd6d TH |
226 | /** |
227 | * task_clear_group_stop_trapping - clear group stop trapping bit | |
228 | * @task: target task | |
229 | * | |
230 | * If GROUP_STOP_TRAPPING is set, a ptracer is waiting for us. Clear it | |
231 | * and wake up the ptracer. Note that we don't need any further locking. | |
232 | * @task->siglock guarantees that @task->parent points to the ptracer. | |
233 | * | |
234 | * CONTEXT: | |
235 | * Must be called with @task->sighand->siglock held. | |
236 | */ | |
237 | static void task_clear_group_stop_trapping(struct task_struct *task) | |
238 | { | |
239 | if (unlikely(task->group_stop & GROUP_STOP_TRAPPING)) { | |
240 | task->group_stop &= ~GROUP_STOP_TRAPPING; | |
241 | __wake_up_sync(&task->parent->signal->wait_chldexit, | |
242 | TASK_UNINTERRUPTIBLE, 1); | |
243 | } | |
244 | } | |
245 | ||
e5c1902e TH |
246 | /** |
247 | * task_clear_group_stop_pending - clear pending group stop | |
248 | * @task: target task | |
249 | * | |
250 | * Clear group stop states for @task. | |
251 | * | |
252 | * CONTEXT: | |
253 | * Must be called with @task->sighand->siglock held. | |
254 | */ | |
39efa3ef | 255 | void task_clear_group_stop_pending(struct task_struct *task) |
e5c1902e | 256 | { |
39efa3ef | 257 | task->group_stop &= ~(GROUP_STOP_PENDING | GROUP_STOP_CONSUME); |
e5c1902e TH |
258 | } |
259 | ||
260 | /** | |
261 | * task_participate_group_stop - participate in a group stop | |
262 | * @task: task participating in a group stop | |
263 | * | |
39efa3ef TH |
264 | * @task has GROUP_STOP_PENDING set and is participating in a group stop. |
265 | * Group stop states are cleared and the group stop count is consumed if | |
266 | * %GROUP_STOP_CONSUME was set. If the consumption completes the group | |
267 | * stop, the appropriate %SIGNAL_* flags are set. | |
e5c1902e TH |
268 | * |
269 | * CONTEXT: | |
270 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
271 | * |
272 | * RETURNS: | |
273 | * %true if group stop completion should be notified to the parent, %false | |
274 | * otherwise. | |
e5c1902e TH |
275 | */ |
276 | static bool task_participate_group_stop(struct task_struct *task) | |
277 | { | |
278 | struct signal_struct *sig = task->signal; | |
279 | bool consume = task->group_stop & GROUP_STOP_CONSUME; | |
280 | ||
39efa3ef TH |
281 | WARN_ON_ONCE(!(task->group_stop & GROUP_STOP_PENDING)); |
282 | ||
e5c1902e TH |
283 | task_clear_group_stop_pending(task); |
284 | ||
285 | if (!consume) | |
286 | return false; | |
287 | ||
288 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
289 | sig->group_stop_count--; | |
290 | ||
244056f9 TH |
291 | /* |
292 | * Tell the caller to notify completion iff we are entering into a | |
293 | * fresh group stop. Read comment in do_signal_stop() for details. | |
294 | */ | |
295 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
e5c1902e TH |
296 | sig->flags = SIGNAL_STOP_STOPPED; |
297 | return true; | |
298 | } | |
299 | return false; | |
300 | } | |
301 | ||
c69e8d9c DH |
302 | /* |
303 | * allocate a new signal queue record | |
304 | * - this may be called without locks if and only if t == current, otherwise an | |
d84f4f99 | 305 | * appopriate lock must be held to stop the target task from exiting |
c69e8d9c | 306 | */ |
f84d49b2 NO |
307 | static struct sigqueue * |
308 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
309 | { |
310 | struct sigqueue *q = NULL; | |
10b1fbdb | 311 | struct user_struct *user; |
1da177e4 | 312 | |
10b1fbdb | 313 | /* |
7cf7db8d TG |
314 | * Protect access to @t credentials. This can go away when all |
315 | * callers hold rcu read lock. | |
10b1fbdb | 316 | */ |
7cf7db8d | 317 | rcu_read_lock(); |
d84f4f99 | 318 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 319 | atomic_inc(&user->sigpending); |
7cf7db8d | 320 | rcu_read_unlock(); |
f84d49b2 | 321 | |
1da177e4 | 322 | if (override_rlimit || |
10b1fbdb | 323 | atomic_read(&user->sigpending) <= |
78d7d407 | 324 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 325 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
326 | } else { |
327 | print_dropped_signal(sig); | |
328 | } | |
329 | ||
1da177e4 | 330 | if (unlikely(q == NULL)) { |
10b1fbdb | 331 | atomic_dec(&user->sigpending); |
d84f4f99 | 332 | free_uid(user); |
1da177e4 LT |
333 | } else { |
334 | INIT_LIST_HEAD(&q->list); | |
335 | q->flags = 0; | |
d84f4f99 | 336 | q->user = user; |
1da177e4 | 337 | } |
d84f4f99 DH |
338 | |
339 | return q; | |
1da177e4 LT |
340 | } |
341 | ||
514a01b8 | 342 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
343 | { |
344 | if (q->flags & SIGQUEUE_PREALLOC) | |
345 | return; | |
346 | atomic_dec(&q->user->sigpending); | |
347 | free_uid(q->user); | |
348 | kmem_cache_free(sigqueue_cachep, q); | |
349 | } | |
350 | ||
6a14c5c9 | 351 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
352 | { |
353 | struct sigqueue *q; | |
354 | ||
355 | sigemptyset(&queue->signal); | |
356 | while (!list_empty(&queue->list)) { | |
357 | q = list_entry(queue->list.next, struct sigqueue , list); | |
358 | list_del_init(&q->list); | |
359 | __sigqueue_free(q); | |
360 | } | |
361 | } | |
362 | ||
363 | /* | |
364 | * Flush all pending signals for a task. | |
365 | */ | |
3bcac026 DH |
366 | void __flush_signals(struct task_struct *t) |
367 | { | |
368 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
369 | flush_sigqueue(&t->pending); | |
370 | flush_sigqueue(&t->signal->shared_pending); | |
371 | } | |
372 | ||
c81addc9 | 373 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
374 | { |
375 | unsigned long flags; | |
376 | ||
377 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
3bcac026 | 378 | __flush_signals(t); |
1da177e4 LT |
379 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
380 | } | |
381 | ||
cbaffba1 ON |
382 | static void __flush_itimer_signals(struct sigpending *pending) |
383 | { | |
384 | sigset_t signal, retain; | |
385 | struct sigqueue *q, *n; | |
386 | ||
387 | signal = pending->signal; | |
388 | sigemptyset(&retain); | |
389 | ||
390 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
391 | int sig = q->info.si_signo; | |
392 | ||
393 | if (likely(q->info.si_code != SI_TIMER)) { | |
394 | sigaddset(&retain, sig); | |
395 | } else { | |
396 | sigdelset(&signal, sig); | |
397 | list_del_init(&q->list); | |
398 | __sigqueue_free(q); | |
399 | } | |
400 | } | |
401 | ||
402 | sigorsets(&pending->signal, &signal, &retain); | |
403 | } | |
404 | ||
405 | void flush_itimer_signals(void) | |
406 | { | |
407 | struct task_struct *tsk = current; | |
408 | unsigned long flags; | |
409 | ||
410 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
411 | __flush_itimer_signals(&tsk->pending); | |
412 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
413 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
414 | } | |
415 | ||
10ab825b ON |
416 | void ignore_signals(struct task_struct *t) |
417 | { | |
418 | int i; | |
419 | ||
420 | for (i = 0; i < _NSIG; ++i) | |
421 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
422 | ||
423 | flush_signals(t); | |
424 | } | |
425 | ||
1da177e4 LT |
426 | /* |
427 | * Flush all handlers for a task. | |
428 | */ | |
429 | ||
430 | void | |
431 | flush_signal_handlers(struct task_struct *t, int force_default) | |
432 | { | |
433 | int i; | |
434 | struct k_sigaction *ka = &t->sighand->action[0]; | |
435 | for (i = _NSIG ; i != 0 ; i--) { | |
436 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
437 | ka->sa.sa_handler = SIG_DFL; | |
438 | ka->sa.sa_flags = 0; | |
439 | sigemptyset(&ka->sa.sa_mask); | |
440 | ka++; | |
441 | } | |
442 | } | |
443 | ||
abd4f750 MAS |
444 | int unhandled_signal(struct task_struct *tsk, int sig) |
445 | { | |
445a91d2 | 446 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 447 | if (is_global_init(tsk)) |
abd4f750 | 448 | return 1; |
445a91d2 | 449 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 450 | return 0; |
43918f2b | 451 | return !tracehook_consider_fatal_signal(tsk, sig); |
abd4f750 MAS |
452 | } |
453 | ||
1da177e4 LT |
454 | |
455 | /* Notify the system that a driver wants to block all signals for this | |
456 | * process, and wants to be notified if any signals at all were to be | |
457 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
458 | * signal will be acted upon after all. If the notifier routine returns 0, | |
459 | * then then signal will be blocked. Only one block per process is | |
460 | * allowed. priv is a pointer to private data that the notifier routine | |
461 | * can use to determine if the signal should be blocked or not. */ | |
462 | ||
463 | void | |
464 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
465 | { | |
466 | unsigned long flags; | |
467 | ||
468 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
469 | current->notifier_mask = mask; | |
470 | current->notifier_data = priv; | |
471 | current->notifier = notifier; | |
472 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
473 | } | |
474 | ||
475 | /* Notify the system that blocking has ended. */ | |
476 | ||
477 | void | |
478 | unblock_all_signals(void) | |
479 | { | |
480 | unsigned long flags; | |
481 | ||
482 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
483 | current->notifier = NULL; | |
484 | current->notifier_data = NULL; | |
485 | recalc_sigpending(); | |
486 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
487 | } | |
488 | ||
100360f0 | 489 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
490 | { |
491 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 492 | |
1da177e4 LT |
493 | /* |
494 | * Collect the siginfo appropriate to this signal. Check if | |
495 | * there is another siginfo for the same signal. | |
496 | */ | |
497 | list_for_each_entry(q, &list->list, list) { | |
498 | if (q->info.si_signo == sig) { | |
d4434207 ON |
499 | if (first) |
500 | goto still_pending; | |
1da177e4 LT |
501 | first = q; |
502 | } | |
503 | } | |
d4434207 ON |
504 | |
505 | sigdelset(&list->signal, sig); | |
506 | ||
1da177e4 | 507 | if (first) { |
d4434207 | 508 | still_pending: |
1da177e4 LT |
509 | list_del_init(&first->list); |
510 | copy_siginfo(info, &first->info); | |
511 | __sigqueue_free(first); | |
1da177e4 | 512 | } else { |
1da177e4 LT |
513 | /* Ok, it wasn't in the queue. This must be |
514 | a fast-pathed signal or we must have been | |
515 | out of queue space. So zero out the info. | |
516 | */ | |
1da177e4 LT |
517 | info->si_signo = sig; |
518 | info->si_errno = 0; | |
7486e5d9 | 519 | info->si_code = SI_USER; |
1da177e4 LT |
520 | info->si_pid = 0; |
521 | info->si_uid = 0; | |
522 | } | |
1da177e4 LT |
523 | } |
524 | ||
525 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
526 | siginfo_t *info) | |
527 | { | |
27d91e07 | 528 | int sig = next_signal(pending, mask); |
1da177e4 | 529 | |
1da177e4 LT |
530 | if (sig) { |
531 | if (current->notifier) { | |
532 | if (sigismember(current->notifier_mask, sig)) { | |
533 | if (!(current->notifier)(current->notifier_data)) { | |
534 | clear_thread_flag(TIF_SIGPENDING); | |
535 | return 0; | |
536 | } | |
537 | } | |
538 | } | |
539 | ||
100360f0 | 540 | collect_signal(sig, pending, info); |
1da177e4 | 541 | } |
1da177e4 LT |
542 | |
543 | return sig; | |
544 | } | |
545 | ||
546 | /* | |
547 | * Dequeue a signal and return the element to the caller, which is | |
548 | * expected to free it. | |
549 | * | |
550 | * All callers have to hold the siglock. | |
551 | */ | |
552 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
553 | { | |
c5363d03 | 554 | int signr; |
caec4e8d BH |
555 | |
556 | /* We only dequeue private signals from ourselves, we don't let | |
557 | * signalfd steal them | |
558 | */ | |
b8fceee1 | 559 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 560 | if (!signr) { |
1da177e4 LT |
561 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
562 | mask, info); | |
8bfd9a7a TG |
563 | /* |
564 | * itimer signal ? | |
565 | * | |
566 | * itimers are process shared and we restart periodic | |
567 | * itimers in the signal delivery path to prevent DoS | |
568 | * attacks in the high resolution timer case. This is | |
569 | * compliant with the old way of self restarting | |
570 | * itimers, as the SIGALRM is a legacy signal and only | |
571 | * queued once. Changing the restart behaviour to | |
572 | * restart the timer in the signal dequeue path is | |
573 | * reducing the timer noise on heavy loaded !highres | |
574 | * systems too. | |
575 | */ | |
576 | if (unlikely(signr == SIGALRM)) { | |
577 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
578 | ||
579 | if (!hrtimer_is_queued(tmr) && | |
580 | tsk->signal->it_real_incr.tv64 != 0) { | |
581 | hrtimer_forward(tmr, tmr->base->get_time(), | |
582 | tsk->signal->it_real_incr); | |
583 | hrtimer_restart(tmr); | |
584 | } | |
585 | } | |
586 | } | |
c5363d03 | 587 | |
b8fceee1 | 588 | recalc_sigpending(); |
c5363d03 PE |
589 | if (!signr) |
590 | return 0; | |
591 | ||
592 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
593 | /* |
594 | * Set a marker that we have dequeued a stop signal. Our | |
595 | * caller might release the siglock and then the pending | |
596 | * stop signal it is about to process is no longer in the | |
597 | * pending bitmasks, but must still be cleared by a SIGCONT | |
598 | * (and overruled by a SIGKILL). So those cases clear this | |
599 | * shared flag after we've set it. Note that this flag may | |
600 | * remain set after the signal we return is ignored or | |
601 | * handled. That doesn't matter because its only purpose | |
602 | * is to alert stop-signal processing code when another | |
603 | * processor has come along and cleared the flag. | |
604 | */ | |
92413d77 | 605 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; |
8bfd9a7a | 606 | } |
c5363d03 | 607 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
608 | /* |
609 | * Release the siglock to ensure proper locking order | |
610 | * of timer locks outside of siglocks. Note, we leave | |
611 | * irqs disabled here, since the posix-timers code is | |
612 | * about to disable them again anyway. | |
613 | */ | |
614 | spin_unlock(&tsk->sighand->siglock); | |
615 | do_schedule_next_timer(info); | |
616 | spin_lock(&tsk->sighand->siglock); | |
617 | } | |
618 | return signr; | |
619 | } | |
620 | ||
621 | /* | |
622 | * Tell a process that it has a new active signal.. | |
623 | * | |
624 | * NOTE! we rely on the previous spin_lock to | |
625 | * lock interrupts for us! We can only be called with | |
626 | * "siglock" held, and the local interrupt must | |
627 | * have been disabled when that got acquired! | |
628 | * | |
629 | * No need to set need_resched since signal event passing | |
630 | * goes through ->blocked | |
631 | */ | |
632 | void signal_wake_up(struct task_struct *t, int resume) | |
633 | { | |
634 | unsigned int mask; | |
635 | ||
636 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
637 | ||
638 | /* | |
f021a3c2 MW |
639 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
640 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
641 | * executing another processor and just now entering stopped state. |
642 | * By using wake_up_state, we ensure the process will wake up and | |
643 | * handle its death signal. | |
644 | */ | |
645 | mask = TASK_INTERRUPTIBLE; | |
646 | if (resume) | |
f021a3c2 | 647 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
648 | if (!wake_up_state(t, mask)) |
649 | kick_process(t); | |
650 | } | |
651 | ||
71fabd5e GA |
652 | /* |
653 | * Remove signals in mask from the pending set and queue. | |
654 | * Returns 1 if any signals were found. | |
655 | * | |
656 | * All callers must be holding the siglock. | |
657 | * | |
658 | * This version takes a sigset mask and looks at all signals, | |
659 | * not just those in the first mask word. | |
660 | */ | |
661 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
662 | { | |
663 | struct sigqueue *q, *n; | |
664 | sigset_t m; | |
665 | ||
666 | sigandsets(&m, mask, &s->signal); | |
667 | if (sigisemptyset(&m)) | |
668 | return 0; | |
669 | ||
670 | signandsets(&s->signal, &s->signal, mask); | |
671 | list_for_each_entry_safe(q, n, &s->list, list) { | |
672 | if (sigismember(mask, q->info.si_signo)) { | |
673 | list_del_init(&q->list); | |
674 | __sigqueue_free(q); | |
675 | } | |
676 | } | |
677 | return 1; | |
678 | } | |
1da177e4 LT |
679 | /* |
680 | * Remove signals in mask from the pending set and queue. | |
681 | * Returns 1 if any signals were found. | |
682 | * | |
683 | * All callers must be holding the siglock. | |
684 | */ | |
685 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
686 | { | |
687 | struct sigqueue *q, *n; | |
688 | ||
689 | if (!sigtestsetmask(&s->signal, mask)) | |
690 | return 0; | |
691 | ||
692 | sigdelsetmask(&s->signal, mask); | |
693 | list_for_each_entry_safe(q, n, &s->list, list) { | |
694 | if (q->info.si_signo < SIGRTMIN && | |
695 | (mask & sigmask(q->info.si_signo))) { | |
696 | list_del_init(&q->list); | |
697 | __sigqueue_free(q); | |
698 | } | |
699 | } | |
700 | return 1; | |
701 | } | |
702 | ||
614c517d ON |
703 | static inline int is_si_special(const struct siginfo *info) |
704 | { | |
705 | return info <= SEND_SIG_FORCED; | |
706 | } | |
707 | ||
708 | static inline bool si_fromuser(const struct siginfo *info) | |
709 | { | |
710 | return info == SEND_SIG_NOINFO || | |
711 | (!is_si_special(info) && SI_FROMUSER(info)); | |
712 | } | |
713 | ||
1da177e4 LT |
714 | /* |
715 | * Bad permissions for sending the signal | |
694f690d | 716 | * - the caller must hold the RCU read lock |
1da177e4 LT |
717 | */ |
718 | static int check_kill_permission(int sig, struct siginfo *info, | |
719 | struct task_struct *t) | |
720 | { | |
065add39 | 721 | const struct cred *cred, *tcred; |
2e2ba22e | 722 | struct pid *sid; |
3b5e9e53 ON |
723 | int error; |
724 | ||
7ed20e1a | 725 | if (!valid_signal(sig)) |
3b5e9e53 ON |
726 | return -EINVAL; |
727 | ||
614c517d | 728 | if (!si_fromuser(info)) |
3b5e9e53 | 729 | return 0; |
e54dc243 | 730 | |
3b5e9e53 ON |
731 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
732 | if (error) | |
1da177e4 | 733 | return error; |
3b5e9e53 | 734 | |
065add39 | 735 | cred = current_cred(); |
c69e8d9c | 736 | tcred = __task_cred(t); |
065add39 ON |
737 | if (!same_thread_group(current, t) && |
738 | (cred->euid ^ tcred->suid) && | |
c69e8d9c DH |
739 | (cred->euid ^ tcred->uid) && |
740 | (cred->uid ^ tcred->suid) && | |
741 | (cred->uid ^ tcred->uid) && | |
2e2ba22e ON |
742 | !capable(CAP_KILL)) { |
743 | switch (sig) { | |
744 | case SIGCONT: | |
2e2ba22e | 745 | sid = task_session(t); |
2e2ba22e ON |
746 | /* |
747 | * We don't return the error if sid == NULL. The | |
748 | * task was unhashed, the caller must notice this. | |
749 | */ | |
750 | if (!sid || sid == task_session(current)) | |
751 | break; | |
752 | default: | |
753 | return -EPERM; | |
754 | } | |
755 | } | |
c2f0c7c3 | 756 | |
e54dc243 | 757 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
758 | } |
759 | ||
1da177e4 | 760 | /* |
7e695a5e ON |
761 | * Handle magic process-wide effects of stop/continue signals. Unlike |
762 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
763 | * time regardless of blocking, ignoring, or handling. This does the |
764 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
765 | * signals. The process stop is done as a signal action for SIG_DFL. |
766 | * | |
767 | * Returns true if the signal should be actually delivered, otherwise | |
768 | * it should be dropped. | |
1da177e4 | 769 | */ |
921cf9f6 | 770 | static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns) |
1da177e4 | 771 | { |
ad16a460 | 772 | struct signal_struct *signal = p->signal; |
1da177e4 LT |
773 | struct task_struct *t; |
774 | ||
7e695a5e | 775 | if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) { |
1da177e4 | 776 | /* |
7e695a5e | 777 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 778 | */ |
7e695a5e | 779 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
780 | /* |
781 | * This is a stop signal. Remove SIGCONT from all queues. | |
782 | */ | |
ad16a460 | 783 | rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); |
1da177e4 LT |
784 | t = p; |
785 | do { | |
786 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
ad16a460 | 787 | } while_each_thread(p, t); |
1da177e4 | 788 | } else if (sig == SIGCONT) { |
fc321d2e | 789 | unsigned int why; |
1da177e4 LT |
790 | /* |
791 | * Remove all stop signals from all queues, | |
792 | * and wake all threads. | |
793 | */ | |
ad16a460 | 794 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
795 | t = p; |
796 | do { | |
797 | unsigned int state; | |
39efa3ef TH |
798 | |
799 | task_clear_group_stop_pending(t); | |
800 | ||
1da177e4 | 801 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); |
1da177e4 LT |
802 | /* |
803 | * If there is a handler for SIGCONT, we must make | |
804 | * sure that no thread returns to user mode before | |
805 | * we post the signal, in case it was the only | |
806 | * thread eligible to run the signal handler--then | |
807 | * it must not do anything between resuming and | |
808 | * running the handler. With the TIF_SIGPENDING | |
809 | * flag set, the thread will pause and acquire the | |
810 | * siglock that we hold now and until we've queued | |
fc321d2e | 811 | * the pending signal. |
1da177e4 LT |
812 | * |
813 | * Wake up the stopped thread _after_ setting | |
814 | * TIF_SIGPENDING | |
815 | */ | |
f021a3c2 | 816 | state = __TASK_STOPPED; |
1da177e4 LT |
817 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { |
818 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
819 | state |= TASK_INTERRUPTIBLE; | |
820 | } | |
821 | wake_up_state(t, state); | |
ad16a460 | 822 | } while_each_thread(p, t); |
1da177e4 | 823 | |
fc321d2e ON |
824 | /* |
825 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
826 | * | |
827 | * If we were in the middle of a group stop, we pretend it | |
828 | * was already finished, and then continued. Since SIGCHLD | |
829 | * doesn't queue we report only CLD_STOPPED, as if the next | |
830 | * CLD_CONTINUED was dropped. | |
831 | */ | |
832 | why = 0; | |
ad16a460 | 833 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 834 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 835 | else if (signal->group_stop_count) |
fc321d2e ON |
836 | why |= SIGNAL_CLD_STOPPED; |
837 | ||
838 | if (why) { | |
021e1ae3 | 839 | /* |
ae6d2ed7 | 840 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
841 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
842 | * notify its parent. See get_signal_to_deliver(). | |
843 | */ | |
ad16a460 ON |
844 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
845 | signal->group_stop_count = 0; | |
846 | signal->group_exit_code = 0; | |
1da177e4 LT |
847 | } else { |
848 | /* | |
849 | * We are not stopped, but there could be a stop | |
850 | * signal in the middle of being processed after | |
851 | * being removed from the queue. Clear that too. | |
852 | */ | |
ad16a460 | 853 | signal->flags &= ~SIGNAL_STOP_DEQUEUED; |
1da177e4 | 854 | } |
1da177e4 | 855 | } |
7e695a5e | 856 | |
921cf9f6 | 857 | return !sig_ignored(p, sig, from_ancestor_ns); |
1da177e4 LT |
858 | } |
859 | ||
71f11dc0 ON |
860 | /* |
861 | * Test if P wants to take SIG. After we've checked all threads with this, | |
862 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
863 | * blocking SIG were ruled out because they are not running and already | |
864 | * have pending signals. Such threads will dequeue from the shared queue | |
865 | * as soon as they're available, so putting the signal on the shared queue | |
866 | * will be equivalent to sending it to one such thread. | |
867 | */ | |
868 | static inline int wants_signal(int sig, struct task_struct *p) | |
869 | { | |
870 | if (sigismember(&p->blocked, sig)) | |
871 | return 0; | |
872 | if (p->flags & PF_EXITING) | |
873 | return 0; | |
874 | if (sig == SIGKILL) | |
875 | return 1; | |
876 | if (task_is_stopped_or_traced(p)) | |
877 | return 0; | |
878 | return task_curr(p) || !signal_pending(p); | |
879 | } | |
880 | ||
5fcd835b | 881 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
882 | { |
883 | struct signal_struct *signal = p->signal; | |
884 | struct task_struct *t; | |
885 | ||
886 | /* | |
887 | * Now find a thread we can wake up to take the signal off the queue. | |
888 | * | |
889 | * If the main thread wants the signal, it gets first crack. | |
890 | * Probably the least surprising to the average bear. | |
891 | */ | |
892 | if (wants_signal(sig, p)) | |
893 | t = p; | |
5fcd835b | 894 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
895 | /* |
896 | * There is just one thread and it does not need to be woken. | |
897 | * It will dequeue unblocked signals before it runs again. | |
898 | */ | |
899 | return; | |
900 | else { | |
901 | /* | |
902 | * Otherwise try to find a suitable thread. | |
903 | */ | |
904 | t = signal->curr_target; | |
905 | while (!wants_signal(sig, t)) { | |
906 | t = next_thread(t); | |
907 | if (t == signal->curr_target) | |
908 | /* | |
909 | * No thread needs to be woken. | |
910 | * Any eligible threads will see | |
911 | * the signal in the queue soon. | |
912 | */ | |
913 | return; | |
914 | } | |
915 | signal->curr_target = t; | |
916 | } | |
917 | ||
918 | /* | |
919 | * Found a killable thread. If the signal will be fatal, | |
920 | * then start taking the whole group down immediately. | |
921 | */ | |
fae5fa44 ON |
922 | if (sig_fatal(p, sig) && |
923 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 924 | !sigismember(&t->real_blocked, sig) && |
445a91d2 | 925 | (sig == SIGKILL || |
43918f2b | 926 | !tracehook_consider_fatal_signal(t, sig))) { |
71f11dc0 ON |
927 | /* |
928 | * This signal will be fatal to the whole group. | |
929 | */ | |
930 | if (!sig_kernel_coredump(sig)) { | |
931 | /* | |
932 | * Start a group exit and wake everybody up. | |
933 | * This way we don't have other threads | |
934 | * running and doing things after a slower | |
935 | * thread has the fatal signal pending. | |
936 | */ | |
937 | signal->flags = SIGNAL_GROUP_EXIT; | |
938 | signal->group_exit_code = sig; | |
939 | signal->group_stop_count = 0; | |
940 | t = p; | |
941 | do { | |
39efa3ef | 942 | task_clear_group_stop_pending(t); |
71f11dc0 ON |
943 | sigaddset(&t->pending.signal, SIGKILL); |
944 | signal_wake_up(t, 1); | |
945 | } while_each_thread(p, t); | |
946 | return; | |
947 | } | |
948 | } | |
949 | ||
950 | /* | |
951 | * The signal is already in the shared-pending queue. | |
952 | * Tell the chosen thread to wake up and dequeue it. | |
953 | */ | |
954 | signal_wake_up(t, sig == SIGKILL); | |
955 | return; | |
956 | } | |
957 | ||
af7fff9c PE |
958 | static inline int legacy_queue(struct sigpending *signals, int sig) |
959 | { | |
960 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
961 | } | |
962 | ||
7978b567 SB |
963 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
964 | int group, int from_ancestor_ns) | |
1da177e4 | 965 | { |
2ca3515a | 966 | struct sigpending *pending; |
6e65acba | 967 | struct sigqueue *q; |
7a0aeb14 | 968 | int override_rlimit; |
1da177e4 | 969 | |
d1eb650f | 970 | trace_signal_generate(sig, info, t); |
0a16b607 | 971 | |
6e65acba | 972 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 SB |
973 | |
974 | if (!prepare_signal(sig, t, from_ancestor_ns)) | |
7e695a5e | 975 | return 0; |
2ca3515a ON |
976 | |
977 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
978 | /* |
979 | * Short-circuit ignored signals and support queuing | |
980 | * exactly one non-rt signal, so that we can get more | |
981 | * detailed information about the cause of the signal. | |
982 | */ | |
7e695a5e | 983 | if (legacy_queue(pending, sig)) |
2acb024d | 984 | return 0; |
1da177e4 LT |
985 | /* |
986 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
987 | * or SIGKILL. | |
988 | */ | |
b67a1b9e | 989 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
990 | goto out_set; |
991 | ||
992 | /* Real-time signals must be queued if sent by sigqueue, or | |
993 | some other real-time mechanism. It is implementation | |
994 | defined whether kill() does so. We attempt to do so, on | |
995 | the principle of least surprise, but since kill is not | |
996 | allowed to fail with EAGAIN when low on memory we just | |
997 | make sure at least one signal gets delivered and don't | |
998 | pass on the info struct. */ | |
999 | ||
7a0aeb14 VN |
1000 | if (sig < SIGRTMIN) |
1001 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1002 | else | |
1003 | override_rlimit = 0; | |
1004 | ||
f84d49b2 | 1005 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1006 | override_rlimit); |
1da177e4 | 1007 | if (q) { |
2ca3515a | 1008 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1009 | switch ((unsigned long) info) { |
b67a1b9e | 1010 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1011 | q->info.si_signo = sig; |
1012 | q->info.si_errno = 0; | |
1013 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1014 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1015 | task_active_pid_ns(t)); |
76aac0e9 | 1016 | q->info.si_uid = current_uid(); |
1da177e4 | 1017 | break; |
b67a1b9e | 1018 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1019 | q->info.si_signo = sig; |
1020 | q->info.si_errno = 0; | |
1021 | q->info.si_code = SI_KERNEL; | |
1022 | q->info.si_pid = 0; | |
1023 | q->info.si_uid = 0; | |
1024 | break; | |
1025 | default: | |
1026 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1027 | if (from_ancestor_ns) |
1028 | q->info.si_pid = 0; | |
1da177e4 LT |
1029 | break; |
1030 | } | |
621d3121 | 1031 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1032 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1033 | /* | |
1034 | * Queue overflow, abort. We may abort if the | |
1035 | * signal was rt and sent by user using something | |
1036 | * other than kill(). | |
1037 | */ | |
1038 | trace_signal_overflow_fail(sig, group, info); | |
1da177e4 | 1039 | return -EAGAIN; |
ba005e1f MH |
1040 | } else { |
1041 | /* | |
1042 | * This is a silent loss of information. We still | |
1043 | * send the signal, but the *info bits are lost. | |
1044 | */ | |
1045 | trace_signal_lose_info(sig, group, info); | |
1046 | } | |
1da177e4 LT |
1047 | } |
1048 | ||
1049 | out_set: | |
53c30337 | 1050 | signalfd_notify(t, sig); |
2ca3515a | 1051 | sigaddset(&pending->signal, sig); |
4cd4b6d4 PE |
1052 | complete_signal(sig, t, group); |
1053 | return 0; | |
1da177e4 LT |
1054 | } |
1055 | ||
7978b567 SB |
1056 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1057 | int group) | |
1058 | { | |
921cf9f6 SB |
1059 | int from_ancestor_ns = 0; |
1060 | ||
1061 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1062 | from_ancestor_ns = si_fromuser(info) && |
1063 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1064 | #endif |
1065 | ||
1066 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1067 | } |
1068 | ||
45807a1d IM |
1069 | static void print_fatal_signal(struct pt_regs *regs, int signr) |
1070 | { | |
1071 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 1072 | current->comm, task_pid_nr(current), signr); |
45807a1d | 1073 | |
ca5cd877 | 1074 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 1075 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
1076 | { |
1077 | int i; | |
1078 | for (i = 0; i < 16; i++) { | |
1079 | unsigned char insn; | |
1080 | ||
b45c6e76 AK |
1081 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1082 | break; | |
45807a1d IM |
1083 | printk("%02x ", insn); |
1084 | } | |
1085 | } | |
1086 | #endif | |
1087 | printk("\n"); | |
3a9f84d3 | 1088 | preempt_disable(); |
45807a1d | 1089 | show_regs(regs); |
3a9f84d3 | 1090 | preempt_enable(); |
45807a1d IM |
1091 | } |
1092 | ||
1093 | static int __init setup_print_fatal_signals(char *str) | |
1094 | { | |
1095 | get_option (&str, &print_fatal_signals); | |
1096 | ||
1097 | return 1; | |
1098 | } | |
1099 | ||
1100 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1101 | |
4cd4b6d4 PE |
1102 | int |
1103 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1104 | { | |
1105 | return send_signal(sig, info, p, 1); | |
1106 | } | |
1107 | ||
1da177e4 LT |
1108 | static int |
1109 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1110 | { | |
4cd4b6d4 | 1111 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1112 | } |
1113 | ||
4a30debf ON |
1114 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1115 | bool group) | |
1116 | { | |
1117 | unsigned long flags; | |
1118 | int ret = -ESRCH; | |
1119 | ||
1120 | if (lock_task_sighand(p, &flags)) { | |
1121 | ret = send_signal(sig, info, p, group); | |
1122 | unlock_task_sighand(p, &flags); | |
1123 | } | |
1124 | ||
1125 | return ret; | |
1126 | } | |
1127 | ||
1da177e4 LT |
1128 | /* |
1129 | * Force a signal that the process can't ignore: if necessary | |
1130 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1131 | * |
1132 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1133 | * since we do not want to have a signal handler that was blocked | |
1134 | * be invoked when user space had explicitly blocked it. | |
1135 | * | |
80fe728d ON |
1136 | * We don't want to have recursive SIGSEGV's etc, for example, |
1137 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1138 | */ |
1da177e4 LT |
1139 | int |
1140 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1141 | { | |
1142 | unsigned long int flags; | |
ae74c3b6 LT |
1143 | int ret, blocked, ignored; |
1144 | struct k_sigaction *action; | |
1da177e4 LT |
1145 | |
1146 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1147 | action = &t->sighand->action[sig-1]; |
1148 | ignored = action->sa.sa_handler == SIG_IGN; | |
1149 | blocked = sigismember(&t->blocked, sig); | |
1150 | if (blocked || ignored) { | |
1151 | action->sa.sa_handler = SIG_DFL; | |
1152 | if (blocked) { | |
1153 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1154 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1155 | } |
1da177e4 | 1156 | } |
80fe728d ON |
1157 | if (action->sa.sa_handler == SIG_DFL) |
1158 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1159 | ret = specific_send_sig_info(sig, info, t); |
1160 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1161 | ||
1162 | return ret; | |
1163 | } | |
1164 | ||
1da177e4 LT |
1165 | /* |
1166 | * Nuke all other threads in the group. | |
1167 | */ | |
09faef11 | 1168 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1169 | { |
09faef11 ON |
1170 | struct task_struct *t = p; |
1171 | int count = 0; | |
1da177e4 | 1172 | |
1da177e4 LT |
1173 | p->signal->group_stop_count = 0; |
1174 | ||
09faef11 | 1175 | while_each_thread(p, t) { |
39efa3ef | 1176 | task_clear_group_stop_pending(t); |
09faef11 ON |
1177 | count++; |
1178 | ||
1179 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1180 | if (t->exit_state) |
1181 | continue; | |
1da177e4 | 1182 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1183 | signal_wake_up(t, 1); |
1184 | } | |
09faef11 ON |
1185 | |
1186 | return count; | |
1da177e4 LT |
1187 | } |
1188 | ||
b8ed374e NK |
1189 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1190 | unsigned long *flags) | |
f63ee72e ON |
1191 | { |
1192 | struct sighand_struct *sighand; | |
1193 | ||
1406f2d3 | 1194 | rcu_read_lock(); |
f63ee72e ON |
1195 | for (;;) { |
1196 | sighand = rcu_dereference(tsk->sighand); | |
1197 | if (unlikely(sighand == NULL)) | |
1198 | break; | |
1199 | ||
1200 | spin_lock_irqsave(&sighand->siglock, *flags); | |
1201 | if (likely(sighand == tsk->sighand)) | |
1202 | break; | |
1203 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
1204 | } | |
1406f2d3 | 1205 | rcu_read_unlock(); |
f63ee72e ON |
1206 | |
1207 | return sighand; | |
1208 | } | |
1209 | ||
c69e8d9c DH |
1210 | /* |
1211 | * send signal info to all the members of a group | |
c69e8d9c | 1212 | */ |
1da177e4 LT |
1213 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1214 | { | |
694f690d DH |
1215 | int ret; |
1216 | ||
1217 | rcu_read_lock(); | |
1218 | ret = check_kill_permission(sig, info, p); | |
1219 | rcu_read_unlock(); | |
f63ee72e | 1220 | |
4a30debf ON |
1221 | if (!ret && sig) |
1222 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1223 | |
1224 | return ret; | |
1225 | } | |
1226 | ||
1227 | /* | |
146a505d | 1228 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1229 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1230 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1231 | */ |
c4b92fc1 | 1232 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1233 | { |
1234 | struct task_struct *p = NULL; | |
1235 | int retval, success; | |
1236 | ||
1da177e4 LT |
1237 | success = 0; |
1238 | retval = -ESRCH; | |
c4b92fc1 | 1239 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1240 | int err = group_send_sig_info(sig, info, p); |
1241 | success |= !err; | |
1242 | retval = err; | |
c4b92fc1 | 1243 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1244 | return success ? 0 : retval; |
1245 | } | |
1246 | ||
c4b92fc1 | 1247 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1248 | { |
d36174bc | 1249 | int error = -ESRCH; |
1da177e4 LT |
1250 | struct task_struct *p; |
1251 | ||
e56d0903 | 1252 | rcu_read_lock(); |
d36174bc | 1253 | retry: |
c4b92fc1 | 1254 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1255 | if (p) { |
1da177e4 | 1256 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1257 | if (unlikely(error == -ESRCH)) |
1258 | /* | |
1259 | * The task was unhashed in between, try again. | |
1260 | * If it is dead, pid_task() will return NULL, | |
1261 | * if we race with de_thread() it will find the | |
1262 | * new leader. | |
1263 | */ | |
1264 | goto retry; | |
1265 | } | |
e56d0903 | 1266 | rcu_read_unlock(); |
6ca25b55 | 1267 | |
1da177e4 LT |
1268 | return error; |
1269 | } | |
1270 | ||
c3de4b38 MW |
1271 | int |
1272 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
c4b92fc1 EB |
1273 | { |
1274 | int error; | |
1275 | rcu_read_lock(); | |
b488893a | 1276 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1277 | rcu_read_unlock(); |
1278 | return error; | |
1279 | } | |
1280 | ||
2425c08b EB |
1281 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1282 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1283 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1284 | { |
1285 | int ret = -EINVAL; | |
1286 | struct task_struct *p; | |
c69e8d9c | 1287 | const struct cred *pcred; |
14d8c9f3 | 1288 | unsigned long flags; |
46113830 HW |
1289 | |
1290 | if (!valid_signal(sig)) | |
1291 | return ret; | |
1292 | ||
14d8c9f3 | 1293 | rcu_read_lock(); |
2425c08b | 1294 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1295 | if (!p) { |
1296 | ret = -ESRCH; | |
1297 | goto out_unlock; | |
1298 | } | |
c69e8d9c | 1299 | pcred = __task_cred(p); |
614c517d | 1300 | if (si_fromuser(info) && |
c69e8d9c DH |
1301 | euid != pcred->suid && euid != pcred->uid && |
1302 | uid != pcred->suid && uid != pcred->uid) { | |
46113830 HW |
1303 | ret = -EPERM; |
1304 | goto out_unlock; | |
1305 | } | |
8f95dc58 DQ |
1306 | ret = security_task_kill(p, info, sig, secid); |
1307 | if (ret) | |
1308 | goto out_unlock; | |
14d8c9f3 TG |
1309 | |
1310 | if (sig) { | |
1311 | if (lock_task_sighand(p, &flags)) { | |
1312 | ret = __send_signal(sig, info, p, 1, 0); | |
1313 | unlock_task_sighand(p, &flags); | |
1314 | } else | |
1315 | ret = -ESRCH; | |
46113830 HW |
1316 | } |
1317 | out_unlock: | |
14d8c9f3 | 1318 | rcu_read_unlock(); |
46113830 HW |
1319 | return ret; |
1320 | } | |
2425c08b | 1321 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1322 | |
1323 | /* | |
1324 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1325 | * | |
1326 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1327 | * is probably wrong. Should make it like BSD or SYSV. | |
1328 | */ | |
1329 | ||
bc64efd2 | 1330 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1331 | { |
8d42db18 | 1332 | int ret; |
d5df763b PE |
1333 | |
1334 | if (pid > 0) { | |
1335 | rcu_read_lock(); | |
1336 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1337 | rcu_read_unlock(); | |
1338 | return ret; | |
1339 | } | |
1340 | ||
1341 | read_lock(&tasklist_lock); | |
1342 | if (pid != -1) { | |
1343 | ret = __kill_pgrp_info(sig, info, | |
1344 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1345 | } else { | |
1da177e4 LT |
1346 | int retval = 0, count = 0; |
1347 | struct task_struct * p; | |
1348 | ||
1da177e4 | 1349 | for_each_process(p) { |
d25141a8 SB |
1350 | if (task_pid_vnr(p) > 1 && |
1351 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1352 | int err = group_send_sig_info(sig, info, p); |
1353 | ++count; | |
1354 | if (err != -EPERM) | |
1355 | retval = err; | |
1356 | } | |
1357 | } | |
8d42db18 | 1358 | ret = count ? retval : -ESRCH; |
1da177e4 | 1359 | } |
d5df763b PE |
1360 | read_unlock(&tasklist_lock); |
1361 | ||
8d42db18 | 1362 | return ret; |
1da177e4 LT |
1363 | } |
1364 | ||
1365 | /* | |
1366 | * These are for backward compatibility with the rest of the kernel source. | |
1367 | */ | |
1368 | ||
1da177e4 LT |
1369 | int |
1370 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1371 | { | |
1da177e4 LT |
1372 | /* |
1373 | * Make sure legacy kernel users don't send in bad values | |
1374 | * (normal paths check this in check_kill_permission). | |
1375 | */ | |
7ed20e1a | 1376 | if (!valid_signal(sig)) |
1da177e4 LT |
1377 | return -EINVAL; |
1378 | ||
4a30debf | 1379 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1380 | } |
1381 | ||
b67a1b9e ON |
1382 | #define __si_special(priv) \ |
1383 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1384 | ||
1da177e4 LT |
1385 | int |
1386 | send_sig(int sig, struct task_struct *p, int priv) | |
1387 | { | |
b67a1b9e | 1388 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1389 | } |
1390 | ||
1da177e4 LT |
1391 | void |
1392 | force_sig(int sig, struct task_struct *p) | |
1393 | { | |
b67a1b9e | 1394 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1395 | } |
1396 | ||
1397 | /* | |
1398 | * When things go south during signal handling, we | |
1399 | * will force a SIGSEGV. And if the signal that caused | |
1400 | * the problem was already a SIGSEGV, we'll want to | |
1401 | * make sure we don't even try to deliver the signal.. | |
1402 | */ | |
1403 | int | |
1404 | force_sigsegv(int sig, struct task_struct *p) | |
1405 | { | |
1406 | if (sig == SIGSEGV) { | |
1407 | unsigned long flags; | |
1408 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1409 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1410 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1411 | } | |
1412 | force_sig(SIGSEGV, p); | |
1413 | return 0; | |
1414 | } | |
1415 | ||
c4b92fc1 EB |
1416 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1417 | { | |
146a505d PE |
1418 | int ret; |
1419 | ||
1420 | read_lock(&tasklist_lock); | |
1421 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1422 | read_unlock(&tasklist_lock); | |
1423 | ||
1424 | return ret; | |
c4b92fc1 EB |
1425 | } |
1426 | EXPORT_SYMBOL(kill_pgrp); | |
1427 | ||
1428 | int kill_pid(struct pid *pid, int sig, int priv) | |
1429 | { | |
1430 | return kill_pid_info(sig, __si_special(priv), pid); | |
1431 | } | |
1432 | EXPORT_SYMBOL(kill_pid); | |
1433 | ||
1da177e4 LT |
1434 | /* |
1435 | * These functions support sending signals using preallocated sigqueue | |
1436 | * structures. This is needed "because realtime applications cannot | |
1437 | * afford to lose notifications of asynchronous events, like timer | |
f84d49b2 | 1438 | * expirations or I/O completions". In the case of Posix Timers |
1da177e4 LT |
1439 | * we allocate the sigqueue structure from the timer_create. If this |
1440 | * allocation fails we are able to report the failure to the application | |
1441 | * with an EAGAIN error. | |
1442 | */ | |
1da177e4 LT |
1443 | struct sigqueue *sigqueue_alloc(void) |
1444 | { | |
f84d49b2 | 1445 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1446 | |
f84d49b2 | 1447 | if (q) |
1da177e4 | 1448 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1449 | |
1450 | return q; | |
1da177e4 LT |
1451 | } |
1452 | ||
1453 | void sigqueue_free(struct sigqueue *q) | |
1454 | { | |
1455 | unsigned long flags; | |
60187d27 ON |
1456 | spinlock_t *lock = ¤t->sighand->siglock; |
1457 | ||
1da177e4 LT |
1458 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1459 | /* | |
c8e85b4f ON |
1460 | * We must hold ->siglock while testing q->list |
1461 | * to serialize with collect_signal() or with | |
da7978b0 | 1462 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1463 | */ |
60187d27 | 1464 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1465 | q->flags &= ~SIGQUEUE_PREALLOC; |
1466 | /* | |
1467 | * If it is queued it will be freed when dequeued, | |
1468 | * like the "regular" sigqueue. | |
1469 | */ | |
60187d27 | 1470 | if (!list_empty(&q->list)) |
c8e85b4f | 1471 | q = NULL; |
60187d27 ON |
1472 | spin_unlock_irqrestore(lock, flags); |
1473 | ||
c8e85b4f ON |
1474 | if (q) |
1475 | __sigqueue_free(q); | |
1da177e4 LT |
1476 | } |
1477 | ||
ac5c2153 | 1478 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1479 | { |
e62e6650 | 1480 | int sig = q->info.si_signo; |
2ca3515a | 1481 | struct sigpending *pending; |
e62e6650 ON |
1482 | unsigned long flags; |
1483 | int ret; | |
2ca3515a | 1484 | |
4cd4b6d4 | 1485 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1486 | |
1487 | ret = -1; | |
1488 | if (!likely(lock_task_sighand(t, &flags))) | |
1489 | goto ret; | |
1490 | ||
7e695a5e | 1491 | ret = 1; /* the signal is ignored */ |
921cf9f6 | 1492 | if (!prepare_signal(sig, t, 0)) |
e62e6650 ON |
1493 | goto out; |
1494 | ||
1495 | ret = 0; | |
9e3bd6c3 PE |
1496 | if (unlikely(!list_empty(&q->list))) { |
1497 | /* | |
1498 | * If an SI_TIMER entry is already queue just increment | |
1499 | * the overrun count. | |
1500 | */ | |
9e3bd6c3 PE |
1501 | BUG_ON(q->info.si_code != SI_TIMER); |
1502 | q->info.si_overrun++; | |
e62e6650 | 1503 | goto out; |
9e3bd6c3 | 1504 | } |
ba661292 | 1505 | q->info.si_overrun = 0; |
9e3bd6c3 | 1506 | |
9e3bd6c3 | 1507 | signalfd_notify(t, sig); |
2ca3515a | 1508 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1509 | list_add_tail(&q->list, &pending->list); |
1510 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1511 | complete_signal(sig, t, group); |
e62e6650 ON |
1512 | out: |
1513 | unlock_task_sighand(t, &flags); | |
1514 | ret: | |
1515 | return ret; | |
9e3bd6c3 PE |
1516 | } |
1517 | ||
1da177e4 LT |
1518 | /* |
1519 | * Let a parent know about the death of a child. | |
1520 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 RM |
1521 | * |
1522 | * Returns -1 if our parent ignored us and so we've switched to | |
1523 | * self-reaping, or else @sig. | |
1da177e4 | 1524 | */ |
2b2a1ff6 | 1525 | int do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1526 | { |
1527 | struct siginfo info; | |
1528 | unsigned long flags; | |
1529 | struct sighand_struct *psig; | |
1b04624f | 1530 | int ret = sig; |
1da177e4 LT |
1531 | |
1532 | BUG_ON(sig == -1); | |
1533 | ||
1534 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1535 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1536 | |
5cb11446 | 1537 | BUG_ON(!task_ptrace(tsk) && |
1da177e4 LT |
1538 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1539 | ||
1540 | info.si_signo = sig; | |
1541 | info.si_errno = 0; | |
b488893a PE |
1542 | /* |
1543 | * we are under tasklist_lock here so our parent is tied to | |
1544 | * us and cannot exit and release its namespace. | |
1545 | * | |
1546 | * the only it can is to switch its nsproxy with sys_unshare, | |
1547 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1548 | * see relevant namespace | |
1549 | * | |
1550 | * write_lock() currently calls preempt_disable() which is the | |
1551 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1552 | * correct to rely on this | |
1553 | */ | |
1554 | rcu_read_lock(); | |
1555 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
c69e8d9c | 1556 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1557 | rcu_read_unlock(); |
1558 | ||
32bd671d PZ |
1559 | info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime, |
1560 | tsk->signal->utime)); | |
1561 | info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime, | |
1562 | tsk->signal->stime)); | |
1da177e4 LT |
1563 | |
1564 | info.si_status = tsk->exit_code & 0x7f; | |
1565 | if (tsk->exit_code & 0x80) | |
1566 | info.si_code = CLD_DUMPED; | |
1567 | else if (tsk->exit_code & 0x7f) | |
1568 | info.si_code = CLD_KILLED; | |
1569 | else { | |
1570 | info.si_code = CLD_EXITED; | |
1571 | info.si_status = tsk->exit_code >> 8; | |
1572 | } | |
1573 | ||
1574 | psig = tsk->parent->sighand; | |
1575 | spin_lock_irqsave(&psig->siglock, flags); | |
5cb11446 | 1576 | if (!task_ptrace(tsk) && sig == SIGCHLD && |
1da177e4 LT |
1577 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1578 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1579 | /* | |
1580 | * We are exiting and our parent doesn't care. POSIX.1 | |
1581 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1582 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1583 | * automatically and not left for our parent's wait4 call. | |
1584 | * Rather than having the parent do it as a magic kind of | |
1585 | * signal handler, we just set this to tell do_exit that we | |
1586 | * can be cleaned up without becoming a zombie. Note that | |
1587 | * we still call __wake_up_parent in this case, because a | |
1588 | * blocked sys_wait4 might now return -ECHILD. | |
1589 | * | |
1590 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1591 | * is implementation-defined: we do (if you don't want | |
1592 | * it, just use SIG_IGN instead). | |
1593 | */ | |
1b04624f | 1594 | ret = tsk->exit_signal = -1; |
1da177e4 | 1595 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
2b2a1ff6 | 1596 | sig = -1; |
1da177e4 | 1597 | } |
7ed20e1a | 1598 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1599 | __group_send_sig_info(sig, &info, tsk->parent); |
1600 | __wake_up_parent(tsk, tsk->parent); | |
1601 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1602 | |
1b04624f | 1603 | return ret; |
1da177e4 LT |
1604 | } |
1605 | ||
75b95953 TH |
1606 | /** |
1607 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1608 | * @tsk: task reporting the state change | |
1609 | * @for_ptracer: the notification is for ptracer | |
1610 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1611 | * | |
1612 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1613 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1614 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1615 | * | |
1616 | * CONTEXT: | |
1617 | * Must be called with tasklist_lock at least read locked. | |
1618 | */ | |
1619 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1620 | bool for_ptracer, int why) | |
1da177e4 LT |
1621 | { |
1622 | struct siginfo info; | |
1623 | unsigned long flags; | |
bc505a47 | 1624 | struct task_struct *parent; |
1da177e4 LT |
1625 | struct sighand_struct *sighand; |
1626 | ||
75b95953 | 1627 | if (for_ptracer) { |
bc505a47 | 1628 | parent = tsk->parent; |
75b95953 | 1629 | } else { |
bc505a47 ON |
1630 | tsk = tsk->group_leader; |
1631 | parent = tsk->real_parent; | |
1632 | } | |
1633 | ||
1da177e4 LT |
1634 | info.si_signo = SIGCHLD; |
1635 | info.si_errno = 0; | |
b488893a PE |
1636 | /* |
1637 | * see comment in do_notify_parent() abot the following 3 lines | |
1638 | */ | |
1639 | rcu_read_lock(); | |
d9265663 | 1640 | info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns); |
c69e8d9c | 1641 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1642 | rcu_read_unlock(); |
1643 | ||
d8878ba3 MK |
1644 | info.si_utime = cputime_to_clock_t(tsk->utime); |
1645 | info.si_stime = cputime_to_clock_t(tsk->stime); | |
1da177e4 LT |
1646 | |
1647 | info.si_code = why; | |
1648 | switch (why) { | |
1649 | case CLD_CONTINUED: | |
1650 | info.si_status = SIGCONT; | |
1651 | break; | |
1652 | case CLD_STOPPED: | |
1653 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1654 | break; | |
1655 | case CLD_TRAPPED: | |
1656 | info.si_status = tsk->exit_code & 0x7f; | |
1657 | break; | |
1658 | default: | |
1659 | BUG(); | |
1660 | } | |
1661 | ||
1662 | sighand = parent->sighand; | |
1663 | spin_lock_irqsave(&sighand->siglock, flags); | |
1664 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1665 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1666 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1667 | /* | |
1668 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1669 | */ | |
1670 | __wake_up_parent(tsk, parent); | |
1671 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1672 | } | |
1673 | ||
d5f70c00 ON |
1674 | static inline int may_ptrace_stop(void) |
1675 | { | |
5cb11446 | 1676 | if (!likely(task_ptrace(current))) |
d5f70c00 | 1677 | return 0; |
d5f70c00 ON |
1678 | /* |
1679 | * Are we in the middle of do_coredump? | |
1680 | * If so and our tracer is also part of the coredump stopping | |
1681 | * is a deadlock situation, and pointless because our tracer | |
1682 | * is dead so don't allow us to stop. | |
1683 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1684 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 ON |
1685 | * is safe to enter schedule(). |
1686 | */ | |
999d9fc1 | 1687 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1688 | unlikely(current->mm == current->parent->mm)) |
1689 | return 0; | |
1690 | ||
1691 | return 1; | |
1692 | } | |
1693 | ||
1a669c2f RM |
1694 | /* |
1695 | * Return nonzero if there is a SIGKILL that should be waking us up. | |
1696 | * Called with the siglock held. | |
1697 | */ | |
1698 | static int sigkill_pending(struct task_struct *tsk) | |
1699 | { | |
3d749b9e ON |
1700 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1701 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1702 | } |
1703 | ||
ceb6bd67 TH |
1704 | /* |
1705 | * Test whether the target task of the usual cldstop notification - the | |
1706 | * real_parent of @child - is in the same group as the ptracer. | |
1707 | */ | |
1708 | static bool real_parent_is_ptracer(struct task_struct *child) | |
1709 | { | |
1710 | return same_thread_group(child->parent, child->real_parent); | |
1711 | } | |
1712 | ||
1da177e4 LT |
1713 | /* |
1714 | * This must be called with current->sighand->siglock held. | |
1715 | * | |
1716 | * This should be the path for all ptrace stops. | |
1717 | * We always set current->last_siginfo while stopped here. | |
1718 | * That makes it a way to test a stopped process for | |
1719 | * being ptrace-stopped vs being job-control-stopped. | |
1720 | * | |
20686a30 ON |
1721 | * If we actually decide not to stop at all because the tracer |
1722 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1723 | */ |
fe1bc6a0 | 1724 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1725 | __releases(¤t->sighand->siglock) |
1726 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1727 | { |
ceb6bd67 TH |
1728 | bool gstop_done = false; |
1729 | ||
1a669c2f RM |
1730 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1731 | /* | |
1732 | * The arch code has something special to do before a | |
1733 | * ptrace stop. This is allowed to block, e.g. for faults | |
1734 | * on user stack pages. We can't keep the siglock while | |
1735 | * calling arch_ptrace_stop, so we must release it now. | |
1736 | * To preserve proper semantics, we must do this before | |
1737 | * any signal bookkeeping like checking group_stop_count. | |
1738 | * Meanwhile, a SIGKILL could come in before we retake the | |
1739 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1740 | * So after regaining the lock, we must check for SIGKILL. | |
1741 | */ | |
1742 | spin_unlock_irq(¤t->sighand->siglock); | |
1743 | arch_ptrace_stop(exit_code, info); | |
1744 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1745 | if (sigkill_pending(current)) |
1746 | return; | |
1a669c2f RM |
1747 | } |
1748 | ||
1da177e4 | 1749 | /* |
0ae8ce1c TH |
1750 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1751 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
1752 | * while siglock was released for the arch hook, PENDING could be | |
1753 | * clear now. We act as if SIGCONT is received after TASK_TRACED | |
1754 | * is entered - ignore it. | |
1da177e4 | 1755 | */ |
0ae8ce1c | 1756 | if (why == CLD_STOPPED && (current->group_stop & GROUP_STOP_PENDING)) |
ceb6bd67 | 1757 | gstop_done = task_participate_group_stop(current); |
1da177e4 LT |
1758 | |
1759 | current->last_siginfo = info; | |
1760 | current->exit_code = exit_code; | |
1761 | ||
d79fdd6d TH |
1762 | /* |
1763 | * TRACED should be visible before TRAPPING is cleared; otherwise, | |
1764 | * the tracer might fail do_wait(). | |
1765 | */ | |
1766 | set_current_state(TASK_TRACED); | |
1767 | ||
1768 | /* | |
1769 | * We're committing to trapping. Clearing GROUP_STOP_TRAPPING and | |
1770 | * transition to TASK_TRACED should be atomic with respect to | |
1771 | * siglock. This hsould be done after the arch hook as siglock is | |
1772 | * released and regrabbed across it. | |
1773 | */ | |
1774 | task_clear_group_stop_trapping(current); | |
1775 | ||
1da177e4 LT |
1776 | spin_unlock_irq(¤t->sighand->siglock); |
1777 | read_lock(&tasklist_lock); | |
3d749b9e | 1778 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1779 | /* |
1780 | * Notify parents of the stop. | |
1781 | * | |
1782 | * While ptraced, there are two parents - the ptracer and | |
1783 | * the real_parent of the group_leader. The ptracer should | |
1784 | * know about every stop while the real parent is only | |
1785 | * interested in the completion of group stop. The states | |
1786 | * for the two don't interact with each other. Notify | |
1787 | * separately unless they're gonna be duplicates. | |
1788 | */ | |
1789 | do_notify_parent_cldstop(current, true, why); | |
1790 | if (gstop_done && !real_parent_is_ptracer(current)) | |
1791 | do_notify_parent_cldstop(current, false, why); | |
1792 | ||
53da1d94 MS |
1793 | /* |
1794 | * Don't want to allow preemption here, because | |
1795 | * sys_ptrace() needs this task to be inactive. | |
1796 | * | |
1797 | * XXX: implement read_unlock_no_resched(). | |
1798 | */ | |
1799 | preempt_disable(); | |
1da177e4 | 1800 | read_unlock(&tasklist_lock); |
53da1d94 | 1801 | preempt_enable_no_resched(); |
1da177e4 LT |
1802 | schedule(); |
1803 | } else { | |
1804 | /* | |
1805 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1806 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1807 | * |
1808 | * If @gstop_done, the ptracer went away between group stop | |
1809 | * completion and here. During detach, it would have set | |
1810 | * GROUP_STOP_PENDING on us and we'll re-enter TASK_STOPPED | |
1811 | * in do_signal_stop() on return, so notifying the real | |
1812 | * parent of the group stop completion is enough. | |
1da177e4 | 1813 | */ |
ceb6bd67 TH |
1814 | if (gstop_done) |
1815 | do_notify_parent_cldstop(current, false, why); | |
1816 | ||
6405f7f4 | 1817 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1818 | if (clear_code) |
1819 | current->exit_code = 0; | |
6405f7f4 | 1820 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1821 | } |
1822 | ||
13b1c3d4 RM |
1823 | /* |
1824 | * While in TASK_TRACED, we were considered "frozen enough". | |
1825 | * Now that we woke up, it's crucial if we're supposed to be | |
1826 | * frozen that we freeze now before running anything substantial. | |
1827 | */ | |
1828 | try_to_freeze(); | |
1829 | ||
1da177e4 LT |
1830 | /* |
1831 | * We are back. Now reacquire the siglock before touching | |
1832 | * last_siginfo, so that we are sure to have synchronized with | |
1833 | * any signal-sending on another CPU that wants to examine it. | |
1834 | */ | |
1835 | spin_lock_irq(¤t->sighand->siglock); | |
1836 | current->last_siginfo = NULL; | |
1837 | ||
1838 | /* | |
1839 | * Queued signals ignored us while we were stopped for tracing. | |
1840 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1841 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1842 | */ |
b74d0deb | 1843 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1844 | } |
1845 | ||
1846 | void ptrace_notify(int exit_code) | |
1847 | { | |
1848 | siginfo_t info; | |
1849 | ||
1850 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1851 | ||
1852 | memset(&info, 0, sizeof info); | |
1853 | info.si_signo = SIGTRAP; | |
1854 | info.si_code = exit_code; | |
b488893a | 1855 | info.si_pid = task_pid_vnr(current); |
76aac0e9 | 1856 | info.si_uid = current_uid(); |
1da177e4 LT |
1857 | |
1858 | /* Let the debugger run. */ | |
1859 | spin_lock_irq(¤t->sighand->siglock); | |
fe1bc6a0 | 1860 | ptrace_stop(exit_code, CLD_TRAPPED, 1, &info); |
1da177e4 LT |
1861 | spin_unlock_irq(¤t->sighand->siglock); |
1862 | } | |
1863 | ||
1da177e4 LT |
1864 | /* |
1865 | * This performs the stopping for SIGSTOP and other stop signals. | |
1866 | * We have to stop all threads in the thread group. | |
1867 | * Returns nonzero if we've actually stopped and released the siglock. | |
1868 | * Returns zero if we didn't stop and still hold the siglock. | |
1869 | */ | |
a122b341 | 1870 | static int do_signal_stop(int signr) |
1da177e4 LT |
1871 | { |
1872 | struct signal_struct *sig = current->signal; | |
1da177e4 | 1873 | |
39efa3ef TH |
1874 | if (!(current->group_stop & GROUP_STOP_PENDING)) { |
1875 | unsigned int gstop = GROUP_STOP_PENDING | GROUP_STOP_CONSUME; | |
f558b7e4 ON |
1876 | struct task_struct *t; |
1877 | ||
d79fdd6d TH |
1878 | /* signr will be recorded in task->group_stop for retries */ |
1879 | WARN_ON_ONCE(signr & ~GROUP_STOP_SIGMASK); | |
1880 | ||
2b201a9e | 1881 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) || |
573cf9ad | 1882 | unlikely(signal_group_exit(sig))) |
f558b7e4 | 1883 | return 0; |
1da177e4 | 1884 | /* |
408a37de TH |
1885 | * There is no group stop already in progress. We must |
1886 | * initiate one now. | |
1887 | * | |
1888 | * While ptraced, a task may be resumed while group stop is | |
1889 | * still in effect and then receive a stop signal and | |
1890 | * initiate another group stop. This deviates from the | |
1891 | * usual behavior as two consecutive stop signals can't | |
1892 | * cause two group stops when !ptraced. | |
1893 | * | |
1894 | * The condition can be distinguished by testing whether | |
1895 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
1896 | * group_exit_code in such case. | |
1897 | * | |
1898 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
1899 | * an intervening stop signal is required to cause two | |
1900 | * continued events regardless of ptrace. | |
1da177e4 | 1901 | */ |
408a37de TH |
1902 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
1903 | sig->group_exit_code = signr; | |
1904 | else | |
1905 | WARN_ON_ONCE(!task_ptrace(current)); | |
1da177e4 | 1906 | |
d79fdd6d TH |
1907 | current->group_stop &= ~GROUP_STOP_SIGMASK; |
1908 | current->group_stop |= signr | gstop; | |
ae6d2ed7 | 1909 | sig->group_stop_count = 1; |
d79fdd6d TH |
1910 | for (t = next_thread(current); t != current; |
1911 | t = next_thread(t)) { | |
1912 | t->group_stop &= ~GROUP_STOP_SIGMASK; | |
1da177e4 | 1913 | /* |
a122b341 ON |
1914 | * Setting state to TASK_STOPPED for a group |
1915 | * stop is always done with the siglock held, | |
1916 | * so this check has no races. | |
1da177e4 | 1917 | */ |
39efa3ef | 1918 | if (!(t->flags & PF_EXITING) && !task_is_stopped(t)) { |
d79fdd6d | 1919 | t->group_stop |= signr | gstop; |
ae6d2ed7 | 1920 | sig->group_stop_count++; |
a122b341 | 1921 | signal_wake_up(t, 0); |
d79fdd6d | 1922 | } else { |
e5c1902e | 1923 | task_clear_group_stop_pending(t); |
d79fdd6d TH |
1924 | } |
1925 | } | |
1da177e4 | 1926 | } |
d79fdd6d | 1927 | retry: |
5224fa36 TH |
1928 | if (likely(!task_ptrace(current))) { |
1929 | int notify = 0; | |
1da177e4 | 1930 | |
5224fa36 TH |
1931 | /* |
1932 | * If there are no other threads in the group, or if there | |
1933 | * is a group stop in progress and we are the last to stop, | |
1934 | * report to the parent. | |
1935 | */ | |
1936 | if (task_participate_group_stop(current)) | |
1937 | notify = CLD_STOPPED; | |
1938 | ||
d79fdd6d | 1939 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
1940 | spin_unlock_irq(¤t->sighand->siglock); |
1941 | ||
62bcf9d9 TH |
1942 | /* |
1943 | * Notify the parent of the group stop completion. Because | |
1944 | * we're not holding either the siglock or tasklist_lock | |
1945 | * here, ptracer may attach inbetween; however, this is for | |
1946 | * group stop and should always be delivered to the real | |
1947 | * parent of the group leader. The new ptracer will get | |
1948 | * its notification when this task transitions into | |
1949 | * TASK_TRACED. | |
1950 | */ | |
5224fa36 TH |
1951 | if (notify) { |
1952 | read_lock(&tasklist_lock); | |
62bcf9d9 | 1953 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
1954 | read_unlock(&tasklist_lock); |
1955 | } | |
1956 | ||
1957 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
1958 | schedule(); | |
1959 | ||
1960 | spin_lock_irq(¤t->sighand->siglock); | |
d79fdd6d TH |
1961 | } else { |
1962 | ptrace_stop(current->group_stop & GROUP_STOP_SIGMASK, | |
1963 | CLD_STOPPED, 0, NULL); | |
1964 | current->exit_code = 0; | |
1965 | } | |
1966 | ||
1967 | /* | |
1968 | * GROUP_STOP_PENDING could be set if another group stop has | |
1969 | * started since being woken up or ptrace wants us to transit | |
1970 | * between TASK_STOPPED and TRACED. Retry group stop. | |
1971 | */ | |
1972 | if (current->group_stop & GROUP_STOP_PENDING) { | |
1973 | WARN_ON_ONCE(!(current->group_stop & GROUP_STOP_SIGMASK)); | |
1974 | goto retry; | |
1975 | } | |
1976 | ||
1977 | /* PTRACE_ATTACH might have raced with task killing, clear trapping */ | |
1978 | task_clear_group_stop_trapping(current); | |
ae6d2ed7 | 1979 | |
5224fa36 | 1980 | spin_unlock_irq(¤t->sighand->siglock); |
ae6d2ed7 RM |
1981 | |
1982 | tracehook_finish_jctl(); | |
dac27f4a | 1983 | |
1da177e4 LT |
1984 | return 1; |
1985 | } | |
1986 | ||
18c98b65 RM |
1987 | static int ptrace_signal(int signr, siginfo_t *info, |
1988 | struct pt_regs *regs, void *cookie) | |
1989 | { | |
5cb11446 | 1990 | if (!task_ptrace(current)) |
18c98b65 RM |
1991 | return signr; |
1992 | ||
1993 | ptrace_signal_deliver(regs, cookie); | |
1994 | ||
1995 | /* Let the debugger run. */ | |
fe1bc6a0 | 1996 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
1997 | |
1998 | /* We're back. Did the debugger cancel the sig? */ | |
1999 | signr = current->exit_code; | |
2000 | if (signr == 0) | |
2001 | return signr; | |
2002 | ||
2003 | current->exit_code = 0; | |
2004 | ||
2005 | /* Update the siginfo structure if the signal has | |
2006 | changed. If the debugger wanted something | |
2007 | specific in the siginfo structure then it should | |
2008 | have updated *info via PTRACE_SETSIGINFO. */ | |
2009 | if (signr != info->si_signo) { | |
2010 | info->si_signo = signr; | |
2011 | info->si_errno = 0; | |
2012 | info->si_code = SI_USER; | |
2013 | info->si_pid = task_pid_vnr(current->parent); | |
c69e8d9c | 2014 | info->si_uid = task_uid(current->parent); |
18c98b65 RM |
2015 | } |
2016 | ||
2017 | /* If the (new) signal is now blocked, requeue it. */ | |
2018 | if (sigismember(¤t->blocked, signr)) { | |
2019 | specific_send_sig_info(signr, info, current); | |
2020 | signr = 0; | |
2021 | } | |
2022 | ||
2023 | return signr; | |
2024 | } | |
2025 | ||
1da177e4 LT |
2026 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
2027 | struct pt_regs *regs, void *cookie) | |
2028 | { | |
f6b76d4f ON |
2029 | struct sighand_struct *sighand = current->sighand; |
2030 | struct signal_struct *signal = current->signal; | |
2031 | int signr; | |
1da177e4 | 2032 | |
13b1c3d4 RM |
2033 | relock: |
2034 | /* | |
2035 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
2036 | * While in TASK_STOPPED, we were considered "frozen enough". | |
2037 | * Now that we woke up, it's crucial if we're supposed to be | |
2038 | * frozen that we freeze now before running anything substantial. | |
2039 | */ | |
fc558a74 RW |
2040 | try_to_freeze(); |
2041 | ||
f6b76d4f | 2042 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2043 | /* |
2044 | * Every stopped thread goes here after wakeup. Check to see if | |
2045 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2046 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2047 | */ | |
f6b76d4f | 2048 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
75b95953 | 2049 | struct task_struct *leader; |
c672af35 TH |
2050 | int why; |
2051 | ||
2052 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2053 | why = CLD_CONTINUED; | |
2054 | else | |
2055 | why = CLD_STOPPED; | |
2056 | ||
f6b76d4f | 2057 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2058 | |
ae6d2ed7 | 2059 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2060 | |
ceb6bd67 TH |
2061 | /* |
2062 | * Notify the parent that we're continuing. This event is | |
2063 | * always per-process and doesn't make whole lot of sense | |
2064 | * for ptracers, who shouldn't consume the state via | |
2065 | * wait(2) either, but, for backward compatibility, notify | |
2066 | * the ptracer of the group leader too unless it's gonna be | |
2067 | * a duplicate. | |
2068 | */ | |
edf2ed15 | 2069 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2070 | |
2071 | do_notify_parent_cldstop(current, false, why); | |
2072 | ||
75b95953 | 2073 | leader = current->group_leader; |
ceb6bd67 TH |
2074 | if (task_ptrace(leader) && !real_parent_is_ptracer(leader)) |
2075 | do_notify_parent_cldstop(leader, true, why); | |
2076 | ||
edf2ed15 | 2077 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2078 | |
e4420551 ON |
2079 | goto relock; |
2080 | } | |
2081 | ||
1da177e4 LT |
2082 | for (;;) { |
2083 | struct k_sigaction *ka; | |
7bcf6a2c RM |
2084 | /* |
2085 | * Tracing can induce an artifical signal and choose sigaction. | |
2086 | * The return value in @signr determines the default action, | |
2087 | * but @info->si_signo is the signal number we will report. | |
2088 | */ | |
2089 | signr = tracehook_get_signal(current, regs, info, return_ka); | |
2090 | if (unlikely(signr < 0)) | |
2091 | goto relock; | |
2092 | if (unlikely(signr != 0)) | |
2093 | ka = return_ka; | |
2094 | else { | |
39efa3ef TH |
2095 | if (unlikely(current->group_stop & |
2096 | GROUP_STOP_PENDING) && do_signal_stop(0)) | |
1be53963 ON |
2097 | goto relock; |
2098 | ||
7bcf6a2c RM |
2099 | signr = dequeue_signal(current, ¤t->blocked, |
2100 | info); | |
1da177e4 | 2101 | |
18c98b65 | 2102 | if (!signr) |
7bcf6a2c RM |
2103 | break; /* will return 0 */ |
2104 | ||
2105 | if (signr != SIGKILL) { | |
2106 | signr = ptrace_signal(signr, info, | |
2107 | regs, cookie); | |
2108 | if (!signr) | |
2109 | continue; | |
2110 | } | |
2111 | ||
2112 | ka = &sighand->action[signr-1]; | |
1da177e4 LT |
2113 | } |
2114 | ||
f9d4257e MH |
2115 | /* Trace actually delivered signals. */ |
2116 | trace_signal_deliver(signr, info, ka); | |
2117 | ||
1da177e4 LT |
2118 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2119 | continue; | |
2120 | if (ka->sa.sa_handler != SIG_DFL) { | |
2121 | /* Run the handler. */ | |
2122 | *return_ka = *ka; | |
2123 | ||
2124 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2125 | ka->sa.sa_handler = SIG_DFL; | |
2126 | ||
2127 | break; /* will return non-zero "signr" value */ | |
2128 | } | |
2129 | ||
2130 | /* | |
2131 | * Now we are doing the default action for this signal. | |
2132 | */ | |
2133 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2134 | continue; | |
2135 | ||
84d73786 | 2136 | /* |
0fbc26a6 | 2137 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2138 | * Container-init gets no signals it doesn't want from same |
2139 | * container. | |
2140 | * | |
2141 | * Note that if global/container-init sees a sig_kernel_only() | |
2142 | * signal here, the signal must have been generated internally | |
2143 | * or must have come from an ancestor namespace. In either | |
2144 | * case, the signal cannot be dropped. | |
84d73786 | 2145 | */ |
fae5fa44 | 2146 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2147 | !sig_kernel_only(signr)) |
1da177e4 LT |
2148 | continue; |
2149 | ||
2150 | if (sig_kernel_stop(signr)) { | |
2151 | /* | |
2152 | * The default action is to stop all threads in | |
2153 | * the thread group. The job control signals | |
2154 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2155 | * always works. Note that siglock needs to be | |
2156 | * dropped during the call to is_orphaned_pgrp() | |
2157 | * because of lock ordering with tasklist_lock. | |
2158 | * This allows an intervening SIGCONT to be posted. | |
2159 | * We need to check for that and bail out if necessary. | |
2160 | */ | |
2161 | if (signr != SIGSTOP) { | |
f6b76d4f | 2162 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2163 | |
2164 | /* signals can be posted during this window */ | |
2165 | ||
3e7cd6c4 | 2166 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2167 | goto relock; |
2168 | ||
f6b76d4f | 2169 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2170 | } |
2171 | ||
7bcf6a2c | 2172 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
2173 | /* It released the siglock. */ |
2174 | goto relock; | |
2175 | } | |
2176 | ||
2177 | /* | |
2178 | * We didn't actually stop, due to a race | |
2179 | * with SIGCONT or something like that. | |
2180 | */ | |
2181 | continue; | |
2182 | } | |
2183 | ||
f6b76d4f | 2184 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2185 | |
2186 | /* | |
2187 | * Anything else is fatal, maybe with a core dump. | |
2188 | */ | |
2189 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2190 | |
1da177e4 | 2191 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2192 | if (print_fatal_signals) |
7bcf6a2c | 2193 | print_fatal_signal(regs, info->si_signo); |
1da177e4 LT |
2194 | /* |
2195 | * If it was able to dump core, this kills all | |
2196 | * other threads in the group and synchronizes with | |
2197 | * their demise. If we lost the race with another | |
2198 | * thread getting here, it set group_exit_code | |
2199 | * first and our do_group_exit call below will use | |
2200 | * that value and ignore the one we pass it. | |
2201 | */ | |
7bcf6a2c | 2202 | do_coredump(info->si_signo, info->si_signo, regs); |
1da177e4 LT |
2203 | } |
2204 | ||
2205 | /* | |
2206 | * Death signals, no core dump. | |
2207 | */ | |
7bcf6a2c | 2208 | do_group_exit(info->si_signo); |
1da177e4 LT |
2209 | /* NOTREACHED */ |
2210 | } | |
f6b76d4f | 2211 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2212 | return signr; |
2213 | } | |
2214 | ||
d12619b5 ON |
2215 | void exit_signals(struct task_struct *tsk) |
2216 | { | |
2217 | int group_stop = 0; | |
5dee1707 | 2218 | struct task_struct *t; |
d12619b5 | 2219 | |
5dee1707 ON |
2220 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2221 | tsk->flags |= PF_EXITING; | |
2222 | return; | |
d12619b5 ON |
2223 | } |
2224 | ||
5dee1707 | 2225 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2226 | /* |
2227 | * From now this task is not visible for group-wide signals, | |
2228 | * see wants_signal(), do_signal_stop(). | |
2229 | */ | |
2230 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
2231 | if (!signal_pending(tsk)) |
2232 | goto out; | |
2233 | ||
2234 | /* It could be that __group_complete_signal() choose us to | |
2235 | * notify about group-wide signal. Another thread should be | |
2236 | * woken now to take the signal since we will not. | |
2237 | */ | |
2238 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
2239 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
2240 | recalc_sigpending_and_wake(t); | |
2241 | ||
39efa3ef | 2242 | if (unlikely(tsk->group_stop & GROUP_STOP_PENDING) && |
e5c1902e | 2243 | task_participate_group_stop(tsk)) |
edf2ed15 | 2244 | group_stop = CLD_STOPPED; |
5dee1707 | 2245 | out: |
d12619b5 ON |
2246 | spin_unlock_irq(&tsk->sighand->siglock); |
2247 | ||
62bcf9d9 TH |
2248 | /* |
2249 | * If group stop has completed, deliver the notification. This | |
2250 | * should always go to the real parent of the group leader. | |
2251 | */ | |
ae6d2ed7 | 2252 | if (unlikely(group_stop)) { |
d12619b5 | 2253 | read_lock(&tasklist_lock); |
62bcf9d9 | 2254 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2255 | read_unlock(&tasklist_lock); |
2256 | } | |
2257 | } | |
2258 | ||
1da177e4 LT |
2259 | EXPORT_SYMBOL(recalc_sigpending); |
2260 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2261 | EXPORT_SYMBOL(flush_signals); | |
2262 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2263 | EXPORT_SYMBOL(send_sig); |
2264 | EXPORT_SYMBOL(send_sig_info); | |
2265 | EXPORT_SYMBOL(sigprocmask); | |
2266 | EXPORT_SYMBOL(block_all_signals); | |
2267 | EXPORT_SYMBOL(unblock_all_signals); | |
2268 | ||
2269 | ||
2270 | /* | |
2271 | * System call entry points. | |
2272 | */ | |
2273 | ||
754fe8d2 | 2274 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2275 | { |
2276 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2277 | return restart->fn(restart); | |
2278 | } | |
2279 | ||
2280 | long do_no_restart_syscall(struct restart_block *param) | |
2281 | { | |
2282 | return -EINTR; | |
2283 | } | |
2284 | ||
2285 | /* | |
2286 | * We don't need to get the kernel lock - this is all local to this | |
2287 | * particular thread.. (and that's good, because this is _heavily_ | |
2288 | * used by various programs) | |
2289 | */ | |
2290 | ||
2291 | /* | |
2292 | * This is also useful for kernel threads that want to temporarily | |
2293 | * (or permanently) block certain signals. | |
2294 | * | |
2295 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2296 | * interface happily blocks "unblockable" signals like SIGKILL | |
2297 | * and friends. | |
2298 | */ | |
2299 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2300 | { | |
2301 | int error; | |
1da177e4 LT |
2302 | |
2303 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
2304 | if (oldset) |
2305 | *oldset = current->blocked; | |
2306 | ||
1da177e4 LT |
2307 | error = 0; |
2308 | switch (how) { | |
2309 | case SIG_BLOCK: | |
2310 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2311 | break; | |
2312 | case SIG_UNBLOCK: | |
2313 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2314 | break; | |
2315 | case SIG_SETMASK: | |
2316 | current->blocked = *set; | |
2317 | break; | |
2318 | default: | |
2319 | error = -EINVAL; | |
2320 | } | |
2321 | recalc_sigpending(); | |
2322 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 2323 | |
1da177e4 LT |
2324 | return error; |
2325 | } | |
2326 | ||
17da2bd9 HC |
2327 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set, |
2328 | sigset_t __user *, oset, size_t, sigsetsize) | |
1da177e4 LT |
2329 | { |
2330 | int error = -EINVAL; | |
2331 | sigset_t old_set, new_set; | |
2332 | ||
2333 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2334 | if (sigsetsize != sizeof(sigset_t)) | |
2335 | goto out; | |
2336 | ||
2337 | if (set) { | |
2338 | error = -EFAULT; | |
2339 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2340 | goto out; | |
2341 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2342 | ||
2343 | error = sigprocmask(how, &new_set, &old_set); | |
2344 | if (error) | |
2345 | goto out; | |
2346 | if (oset) | |
2347 | goto set_old; | |
2348 | } else if (oset) { | |
2349 | spin_lock_irq(¤t->sighand->siglock); | |
2350 | old_set = current->blocked; | |
2351 | spin_unlock_irq(¤t->sighand->siglock); | |
2352 | ||
2353 | set_old: | |
2354 | error = -EFAULT; | |
2355 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2356 | goto out; | |
2357 | } | |
2358 | error = 0; | |
2359 | out: | |
2360 | return error; | |
2361 | } | |
2362 | ||
2363 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2364 | { | |
2365 | long error = -EINVAL; | |
2366 | sigset_t pending; | |
2367 | ||
2368 | if (sigsetsize > sizeof(sigset_t)) | |
2369 | goto out; | |
2370 | ||
2371 | spin_lock_irq(¤t->sighand->siglock); | |
2372 | sigorsets(&pending, ¤t->pending.signal, | |
2373 | ¤t->signal->shared_pending.signal); | |
2374 | spin_unlock_irq(¤t->sighand->siglock); | |
2375 | ||
2376 | /* Outside the lock because only this thread touches it. */ | |
2377 | sigandsets(&pending, ¤t->blocked, &pending); | |
2378 | ||
2379 | error = -EFAULT; | |
2380 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2381 | error = 0; | |
2382 | ||
2383 | out: | |
2384 | return error; | |
2385 | } | |
2386 | ||
17da2bd9 | 2387 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize) |
1da177e4 LT |
2388 | { |
2389 | return do_sigpending(set, sigsetsize); | |
2390 | } | |
2391 | ||
2392 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2393 | ||
2394 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2395 | { | |
2396 | int err; | |
2397 | ||
2398 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2399 | return -EFAULT; | |
2400 | if (from->si_code < 0) | |
2401 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2402 | ? -EFAULT : 0; | |
2403 | /* | |
2404 | * If you change siginfo_t structure, please be sure | |
2405 | * this code is fixed accordingly. | |
fba2afaa DL |
2406 | * Please remember to update the signalfd_copyinfo() function |
2407 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2408 | * It should never copy any pad contained in the structure |
2409 | * to avoid security leaks, but must copy the generic | |
2410 | * 3 ints plus the relevant union member. | |
2411 | */ | |
2412 | err = __put_user(from->si_signo, &to->si_signo); | |
2413 | err |= __put_user(from->si_errno, &to->si_errno); | |
2414 | err |= __put_user((short)from->si_code, &to->si_code); | |
2415 | switch (from->si_code & __SI_MASK) { | |
2416 | case __SI_KILL: | |
2417 | err |= __put_user(from->si_pid, &to->si_pid); | |
2418 | err |= __put_user(from->si_uid, &to->si_uid); | |
2419 | break; | |
2420 | case __SI_TIMER: | |
2421 | err |= __put_user(from->si_tid, &to->si_tid); | |
2422 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2423 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2424 | break; | |
2425 | case __SI_POLL: | |
2426 | err |= __put_user(from->si_band, &to->si_band); | |
2427 | err |= __put_user(from->si_fd, &to->si_fd); | |
2428 | break; | |
2429 | case __SI_FAULT: | |
2430 | err |= __put_user(from->si_addr, &to->si_addr); | |
2431 | #ifdef __ARCH_SI_TRAPNO | |
2432 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2433 | #endif |
2434 | #ifdef BUS_MCEERR_AO | |
2435 | /* | |
2436 | * Other callers might not initialize the si_lsb field, | |
2437 | * so check explicitely for the right codes here. | |
2438 | */ | |
2439 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2440 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2441 | #endif |
2442 | break; | |
2443 | case __SI_CHLD: | |
2444 | err |= __put_user(from->si_pid, &to->si_pid); | |
2445 | err |= __put_user(from->si_uid, &to->si_uid); | |
2446 | err |= __put_user(from->si_status, &to->si_status); | |
2447 | err |= __put_user(from->si_utime, &to->si_utime); | |
2448 | err |= __put_user(from->si_stime, &to->si_stime); | |
2449 | break; | |
2450 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2451 | case __SI_MESGQ: /* But this is */ | |
2452 | err |= __put_user(from->si_pid, &to->si_pid); | |
2453 | err |= __put_user(from->si_uid, &to->si_uid); | |
2454 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2455 | break; | |
2456 | default: /* this is just in case for now ... */ | |
2457 | err |= __put_user(from->si_pid, &to->si_pid); | |
2458 | err |= __put_user(from->si_uid, &to->si_uid); | |
2459 | break; | |
2460 | } | |
2461 | return err; | |
2462 | } | |
2463 | ||
2464 | #endif | |
2465 | ||
17da2bd9 HC |
2466 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2467 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2468 | size_t, sigsetsize) | |
1da177e4 LT |
2469 | { |
2470 | int ret, sig; | |
2471 | sigset_t these; | |
2472 | struct timespec ts; | |
2473 | siginfo_t info; | |
2474 | long timeout = 0; | |
2475 | ||
2476 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2477 | if (sigsetsize != sizeof(sigset_t)) | |
2478 | return -EINVAL; | |
2479 | ||
2480 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2481 | return -EFAULT; | |
2482 | ||
2483 | /* | |
2484 | * Invert the set of allowed signals to get those we | |
2485 | * want to block. | |
2486 | */ | |
2487 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2488 | signotset(&these); | |
2489 | ||
2490 | if (uts) { | |
2491 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2492 | return -EFAULT; | |
2493 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2494 | || ts.tv_sec < 0) | |
2495 | return -EINVAL; | |
2496 | } | |
2497 | ||
2498 | spin_lock_irq(¤t->sighand->siglock); | |
2499 | sig = dequeue_signal(current, &these, &info); | |
2500 | if (!sig) { | |
2501 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2502 | if (uts) | |
2503 | timeout = (timespec_to_jiffies(&ts) | |
2504 | + (ts.tv_sec || ts.tv_nsec)); | |
2505 | ||
2506 | if (timeout) { | |
2507 | /* None ready -- temporarily unblock those we're | |
2508 | * interested while we are sleeping in so that we'll | |
2509 | * be awakened when they arrive. */ | |
2510 | current->real_blocked = current->blocked; | |
2511 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2512 | recalc_sigpending(); | |
2513 | spin_unlock_irq(¤t->sighand->siglock); | |
2514 | ||
75bcc8c5 | 2515 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2516 | |
1da177e4 LT |
2517 | spin_lock_irq(¤t->sighand->siglock); |
2518 | sig = dequeue_signal(current, &these, &info); | |
2519 | current->blocked = current->real_blocked; | |
2520 | siginitset(¤t->real_blocked, 0); | |
2521 | recalc_sigpending(); | |
2522 | } | |
2523 | } | |
2524 | spin_unlock_irq(¤t->sighand->siglock); | |
2525 | ||
2526 | if (sig) { | |
2527 | ret = sig; | |
2528 | if (uinfo) { | |
2529 | if (copy_siginfo_to_user(uinfo, &info)) | |
2530 | ret = -EFAULT; | |
2531 | } | |
2532 | } else { | |
2533 | ret = -EAGAIN; | |
2534 | if (timeout) | |
2535 | ret = -EINTR; | |
2536 | } | |
2537 | ||
2538 | return ret; | |
2539 | } | |
2540 | ||
17da2bd9 | 2541 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2542 | { |
2543 | struct siginfo info; | |
2544 | ||
2545 | info.si_signo = sig; | |
2546 | info.si_errno = 0; | |
2547 | info.si_code = SI_USER; | |
b488893a | 2548 | info.si_pid = task_tgid_vnr(current); |
76aac0e9 | 2549 | info.si_uid = current_uid(); |
1da177e4 LT |
2550 | |
2551 | return kill_something_info(sig, &info, pid); | |
2552 | } | |
2553 | ||
30b4ae8a TG |
2554 | static int |
2555 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2556 | { |
1da177e4 | 2557 | struct task_struct *p; |
30b4ae8a | 2558 | int error = -ESRCH; |
1da177e4 | 2559 | |
3547ff3a | 2560 | rcu_read_lock(); |
228ebcbe | 2561 | p = find_task_by_vpid(pid); |
b488893a | 2562 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2563 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2564 | /* |
2565 | * The null signal is a permissions and process existence | |
2566 | * probe. No signal is actually delivered. | |
2567 | */ | |
4a30debf ON |
2568 | if (!error && sig) { |
2569 | error = do_send_sig_info(sig, info, p, false); | |
2570 | /* | |
2571 | * If lock_task_sighand() failed we pretend the task | |
2572 | * dies after receiving the signal. The window is tiny, | |
2573 | * and the signal is private anyway. | |
2574 | */ | |
2575 | if (unlikely(error == -ESRCH)) | |
2576 | error = 0; | |
1da177e4 LT |
2577 | } |
2578 | } | |
3547ff3a | 2579 | rcu_read_unlock(); |
6dd69f10 | 2580 | |
1da177e4 LT |
2581 | return error; |
2582 | } | |
2583 | ||
30b4ae8a TG |
2584 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2585 | { | |
2586 | struct siginfo info; | |
2587 | ||
2588 | info.si_signo = sig; | |
2589 | info.si_errno = 0; | |
2590 | info.si_code = SI_TKILL; | |
2591 | info.si_pid = task_tgid_vnr(current); | |
2592 | info.si_uid = current_uid(); | |
2593 | ||
2594 | return do_send_specific(tgid, pid, sig, &info); | |
2595 | } | |
2596 | ||
6dd69f10 VL |
2597 | /** |
2598 | * sys_tgkill - send signal to one specific thread | |
2599 | * @tgid: the thread group ID of the thread | |
2600 | * @pid: the PID of the thread | |
2601 | * @sig: signal to be sent | |
2602 | * | |
72fd4a35 | 2603 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2604 | * exists but it's not belonging to the target process anymore. This |
2605 | * method solves the problem of threads exiting and PIDs getting reused. | |
2606 | */ | |
a5f8fa9e | 2607 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2608 | { |
2609 | /* This is only valid for single tasks */ | |
2610 | if (pid <= 0 || tgid <= 0) | |
2611 | return -EINVAL; | |
2612 | ||
2613 | return do_tkill(tgid, pid, sig); | |
2614 | } | |
2615 | ||
1da177e4 LT |
2616 | /* |
2617 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2618 | */ | |
a5f8fa9e | 2619 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2620 | { |
1da177e4 LT |
2621 | /* This is only valid for single tasks */ |
2622 | if (pid <= 0) | |
2623 | return -EINVAL; | |
2624 | ||
6dd69f10 | 2625 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2626 | } |
2627 | ||
a5f8fa9e HC |
2628 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2629 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2630 | { |
2631 | siginfo_t info; | |
2632 | ||
2633 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2634 | return -EFAULT; | |
2635 | ||
2636 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2637 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2638 | */ | |
2639 | if (info.si_code != SI_QUEUE) { | |
2640 | /* We used to allow any < 0 si_code */ | |
2641 | WARN_ON_ONCE(info.si_code < 0); | |
1da177e4 | 2642 | return -EPERM; |
da48524e | 2643 | } |
1da177e4 LT |
2644 | info.si_signo = sig; |
2645 | ||
2646 | /* POSIX.1b doesn't mention process groups. */ | |
2647 | return kill_proc_info(sig, &info, pid); | |
2648 | } | |
2649 | ||
62ab4505 TG |
2650 | long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
2651 | { | |
2652 | /* This is only valid for single tasks */ | |
2653 | if (pid <= 0 || tgid <= 0) | |
2654 | return -EINVAL; | |
2655 | ||
2656 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2657 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2658 | */ | |
2659 | if (info->si_code != SI_QUEUE) { | |
2660 | /* We used to allow any < 0 si_code */ | |
2661 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 2662 | return -EPERM; |
da48524e | 2663 | } |
62ab4505 TG |
2664 | info->si_signo = sig; |
2665 | ||
2666 | return do_send_specific(tgid, pid, sig, info); | |
2667 | } | |
2668 | ||
2669 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
2670 | siginfo_t __user *, uinfo) | |
2671 | { | |
2672 | siginfo_t info; | |
2673 | ||
2674 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2675 | return -EFAULT; | |
2676 | ||
2677 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
2678 | } | |
2679 | ||
88531f72 | 2680 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 2681 | { |
93585eea | 2682 | struct task_struct *t = current; |
1da177e4 | 2683 | struct k_sigaction *k; |
71fabd5e | 2684 | sigset_t mask; |
1da177e4 | 2685 | |
7ed20e1a | 2686 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2687 | return -EINVAL; |
2688 | ||
93585eea | 2689 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
2690 | |
2691 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2692 | if (oact) |
2693 | *oact = *k; | |
2694 | ||
2695 | if (act) { | |
9ac95f2f ON |
2696 | sigdelsetmask(&act->sa.sa_mask, |
2697 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2698 | *k = *act; |
1da177e4 LT |
2699 | /* |
2700 | * POSIX 3.3.1.3: | |
2701 | * "Setting a signal action to SIG_IGN for a signal that is | |
2702 | * pending shall cause the pending signal to be discarded, | |
2703 | * whether or not it is blocked." | |
2704 | * | |
2705 | * "Setting a signal action to SIG_DFL for a signal that is | |
2706 | * pending and whose default action is to ignore the signal | |
2707 | * (for example, SIGCHLD), shall cause the pending signal to | |
2708 | * be discarded, whether or not it is blocked" | |
2709 | */ | |
35de254d | 2710 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
2711 | sigemptyset(&mask); |
2712 | sigaddset(&mask, sig); | |
2713 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2714 | do { |
71fabd5e | 2715 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2716 | t = next_thread(t); |
2717 | } while (t != current); | |
1da177e4 | 2718 | } |
1da177e4 LT |
2719 | } |
2720 | ||
2721 | spin_unlock_irq(¤t->sighand->siglock); | |
2722 | return 0; | |
2723 | } | |
2724 | ||
2725 | int | |
2726 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2727 | { | |
2728 | stack_t oss; | |
2729 | int error; | |
2730 | ||
0083fc2c LT |
2731 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
2732 | oss.ss_size = current->sas_ss_size; | |
2733 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
2734 | |
2735 | if (uss) { | |
2736 | void __user *ss_sp; | |
2737 | size_t ss_size; | |
2738 | int ss_flags; | |
2739 | ||
2740 | error = -EFAULT; | |
0dd8486b LT |
2741 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
2742 | goto out; | |
2743 | error = __get_user(ss_sp, &uss->ss_sp) | | |
2744 | __get_user(ss_flags, &uss->ss_flags) | | |
2745 | __get_user(ss_size, &uss->ss_size); | |
2746 | if (error) | |
1da177e4 LT |
2747 | goto out; |
2748 | ||
2749 | error = -EPERM; | |
2750 | if (on_sig_stack(sp)) | |
2751 | goto out; | |
2752 | ||
2753 | error = -EINVAL; | |
2754 | /* | |
2755 | * | |
2756 | * Note - this code used to test ss_flags incorrectly | |
2757 | * old code may have been written using ss_flags==0 | |
2758 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2759 | * way that worked) - this fix preserves that older | |
2760 | * mechanism | |
2761 | */ | |
2762 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2763 | goto out; | |
2764 | ||
2765 | if (ss_flags == SS_DISABLE) { | |
2766 | ss_size = 0; | |
2767 | ss_sp = NULL; | |
2768 | } else { | |
2769 | error = -ENOMEM; | |
2770 | if (ss_size < MINSIGSTKSZ) | |
2771 | goto out; | |
2772 | } | |
2773 | ||
2774 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2775 | current->sas_ss_size = ss_size; | |
2776 | } | |
2777 | ||
0083fc2c | 2778 | error = 0; |
1da177e4 LT |
2779 | if (uoss) { |
2780 | error = -EFAULT; | |
0083fc2c | 2781 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 2782 | goto out; |
0083fc2c LT |
2783 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
2784 | __put_user(oss.ss_size, &uoss->ss_size) | | |
2785 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
2786 | } |
2787 | ||
1da177e4 LT |
2788 | out: |
2789 | return error; | |
2790 | } | |
2791 | ||
2792 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2793 | ||
b290ebe2 | 2794 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 LT |
2795 | { |
2796 | return do_sigpending(set, sizeof(*set)); | |
2797 | } | |
2798 | ||
2799 | #endif | |
2800 | ||
2801 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2802 | /* Some platforms have their own version with special arguments others | |
2803 | support only sys_rt_sigprocmask. */ | |
2804 | ||
b290ebe2 HC |
2805 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set, |
2806 | old_sigset_t __user *, oset) | |
1da177e4 LT |
2807 | { |
2808 | int error; | |
2809 | old_sigset_t old_set, new_set; | |
2810 | ||
2811 | if (set) { | |
2812 | error = -EFAULT; | |
2813 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2814 | goto out; | |
2815 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2816 | ||
2817 | spin_lock_irq(¤t->sighand->siglock); | |
2818 | old_set = current->blocked.sig[0]; | |
2819 | ||
2820 | error = 0; | |
2821 | switch (how) { | |
2822 | default: | |
2823 | error = -EINVAL; | |
2824 | break; | |
2825 | case SIG_BLOCK: | |
2826 | sigaddsetmask(¤t->blocked, new_set); | |
2827 | break; | |
2828 | case SIG_UNBLOCK: | |
2829 | sigdelsetmask(¤t->blocked, new_set); | |
2830 | break; | |
2831 | case SIG_SETMASK: | |
2832 | current->blocked.sig[0] = new_set; | |
2833 | break; | |
2834 | } | |
2835 | ||
2836 | recalc_sigpending(); | |
2837 | spin_unlock_irq(¤t->sighand->siglock); | |
2838 | if (error) | |
2839 | goto out; | |
2840 | if (oset) | |
2841 | goto set_old; | |
2842 | } else if (oset) { | |
2843 | old_set = current->blocked.sig[0]; | |
2844 | set_old: | |
2845 | error = -EFAULT; | |
2846 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2847 | goto out; | |
2848 | } | |
2849 | error = 0; | |
2850 | out: | |
2851 | return error; | |
2852 | } | |
2853 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2854 | ||
2855 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
d4e82042 HC |
2856 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
2857 | const struct sigaction __user *, act, | |
2858 | struct sigaction __user *, oact, | |
2859 | size_t, sigsetsize) | |
1da177e4 LT |
2860 | { |
2861 | struct k_sigaction new_sa, old_sa; | |
2862 | int ret = -EINVAL; | |
2863 | ||
2864 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2865 | if (sigsetsize != sizeof(sigset_t)) | |
2866 | goto out; | |
2867 | ||
2868 | if (act) { | |
2869 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2870 | return -EFAULT; | |
2871 | } | |
2872 | ||
2873 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2874 | ||
2875 | if (!ret && oact) { | |
2876 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2877 | return -EFAULT; | |
2878 | } | |
2879 | out: | |
2880 | return ret; | |
2881 | } | |
2882 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2883 | ||
2884 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2885 | ||
2886 | /* | |
2887 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2888 | */ | |
a5f8fa9e | 2889 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
2890 | { |
2891 | /* SMP safe */ | |
2892 | return current->blocked.sig[0]; | |
2893 | } | |
2894 | ||
a5f8fa9e | 2895 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 LT |
2896 | { |
2897 | int old; | |
2898 | ||
2899 | spin_lock_irq(¤t->sighand->siglock); | |
2900 | old = current->blocked.sig[0]; | |
2901 | ||
2902 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2903 | sigmask(SIGSTOP))); | |
2904 | recalc_sigpending(); | |
2905 | spin_unlock_irq(¤t->sighand->siglock); | |
2906 | ||
2907 | return old; | |
2908 | } | |
2909 | #endif /* __ARCH_WANT_SGETMASK */ | |
2910 | ||
2911 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2912 | /* | |
2913 | * For backwards compatibility. Functionality superseded by sigaction. | |
2914 | */ | |
a5f8fa9e | 2915 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
2916 | { |
2917 | struct k_sigaction new_sa, old_sa; | |
2918 | int ret; | |
2919 | ||
2920 | new_sa.sa.sa_handler = handler; | |
2921 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2922 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2923 | |
2924 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2925 | ||
2926 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2927 | } | |
2928 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2929 | ||
2930 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2931 | ||
a5f8fa9e | 2932 | SYSCALL_DEFINE0(pause) |
1da177e4 LT |
2933 | { |
2934 | current->state = TASK_INTERRUPTIBLE; | |
2935 | schedule(); | |
2936 | return -ERESTARTNOHAND; | |
2937 | } | |
2938 | ||
2939 | #endif | |
2940 | ||
150256d8 | 2941 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
d4e82042 | 2942 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
2943 | { |
2944 | sigset_t newset; | |
2945 | ||
2946 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2947 | if (sigsetsize != sizeof(sigset_t)) | |
2948 | return -EINVAL; | |
2949 | ||
2950 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2951 | return -EFAULT; | |
2952 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2953 | ||
2954 | spin_lock_irq(¤t->sighand->siglock); | |
2955 | current->saved_sigmask = current->blocked; | |
2956 | current->blocked = newset; | |
2957 | recalc_sigpending(); | |
2958 | spin_unlock_irq(¤t->sighand->siglock); | |
2959 | ||
2960 | current->state = TASK_INTERRUPTIBLE; | |
2961 | schedule(); | |
4e4c22c7 | 2962 | set_restore_sigmask(); |
150256d8 DW |
2963 | return -ERESTARTNOHAND; |
2964 | } | |
2965 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2966 | ||
f269fdd1 DH |
2967 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2968 | { | |
2969 | return NULL; | |
2970 | } | |
2971 | ||
1da177e4 LT |
2972 | void __init signals_init(void) |
2973 | { | |
0a31bd5f | 2974 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2975 | } |
67fc4e0c JW |
2976 | |
2977 | #ifdef CONFIG_KGDB_KDB | |
2978 | #include <linux/kdb.h> | |
2979 | /* | |
2980 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
2981 | * signal internals. This function checks if the required locks are | |
2982 | * available before calling the main signal code, to avoid kdb | |
2983 | * deadlocks. | |
2984 | */ | |
2985 | void | |
2986 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
2987 | { | |
2988 | static struct task_struct *kdb_prev_t; | |
2989 | int sig, new_t; | |
2990 | if (!spin_trylock(&t->sighand->siglock)) { | |
2991 | kdb_printf("Can't do kill command now.\n" | |
2992 | "The sigmask lock is held somewhere else in " | |
2993 | "kernel, try again later\n"); | |
2994 | return; | |
2995 | } | |
2996 | spin_unlock(&t->sighand->siglock); | |
2997 | new_t = kdb_prev_t != t; | |
2998 | kdb_prev_t = t; | |
2999 | if (t->state != TASK_RUNNING && new_t) { | |
3000 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3001 | "kdb risks deadlock\n" | |
3002 | "on the run queue locks. " | |
3003 | "The signal has _not_ been sent.\n" | |
3004 | "Reissue the kill command if you want to risk " | |
3005 | "the deadlock.\n"); | |
3006 | return; | |
3007 | } | |
3008 | sig = info->si_signo; | |
3009 | if (send_sig_info(sig, info, t)) | |
3010 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3011 | sig, t->pid); | |
3012 | else | |
3013 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3014 | } | |
3015 | #endif /* CONFIG_KGDB_KDB */ |