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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 LT |
13 | #include <linux/slab.h> |
14 | #include <linux/module.h> | |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
20 | #include <linux/security.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/ptrace.h> | |
7ed20e1a | 23 | #include <linux/signal.h> |
fba2afaa | 24 | #include <linux/signalfd.h> |
f84d49b2 | 25 | #include <linux/ratelimit.h> |
35de254d | 26 | #include <linux/tracehook.h> |
c59ede7b | 27 | #include <linux/capability.h> |
7dfb7103 | 28 | #include <linux/freezer.h> |
84d73786 SB |
29 | #include <linux/pid_namespace.h> |
30 | #include <linux/nsproxy.h> | |
d1eb650f MH |
31 | #define CREATE_TRACE_POINTS |
32 | #include <trace/events/signal.h> | |
84d73786 | 33 | |
1da177e4 LT |
34 | #include <asm/param.h> |
35 | #include <asm/uaccess.h> | |
36 | #include <asm/unistd.h> | |
37 | #include <asm/siginfo.h> | |
e1396065 | 38 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
39 | |
40 | /* | |
41 | * SLAB caches for signal bits. | |
42 | */ | |
43 | ||
e18b890b | 44 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 45 | |
f84d49b2 NO |
46 | int print_fatal_signals __read_mostly; |
47 | ||
35de254d | 48 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 49 | { |
35de254d RM |
50 | return t->sighand->action[sig - 1].sa.sa_handler; |
51 | } | |
93585eea | 52 | |
35de254d RM |
53 | static int sig_handler_ignored(void __user *handler, int sig) |
54 | { | |
93585eea | 55 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
56 | return handler == SIG_IGN || |
57 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
58 | } | |
1da177e4 | 59 | |
921cf9f6 SB |
60 | static int sig_task_ignored(struct task_struct *t, int sig, |
61 | int from_ancestor_ns) | |
1da177e4 | 62 | { |
35de254d | 63 | void __user *handler; |
1da177e4 | 64 | |
f008faff ON |
65 | handler = sig_handler(t, sig); |
66 | ||
67 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
921cf9f6 | 68 | handler == SIG_DFL && !from_ancestor_ns) |
f008faff ON |
69 | return 1; |
70 | ||
71 | return sig_handler_ignored(handler, sig); | |
72 | } | |
73 | ||
921cf9f6 | 74 | static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns) |
f008faff | 75 | { |
1da177e4 LT |
76 | /* |
77 | * Blocked signals are never ignored, since the | |
78 | * signal handler may change by the time it is | |
79 | * unblocked. | |
80 | */ | |
325d22df | 81 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
82 | return 0; |
83 | ||
921cf9f6 | 84 | if (!sig_task_ignored(t, sig, from_ancestor_ns)) |
35de254d RM |
85 | return 0; |
86 | ||
87 | /* | |
88 | * Tracers may want to know about even ignored signals. | |
89 | */ | |
43918f2b | 90 | return !tracehook_consider_ignored_signal(t, sig); |
1da177e4 LT |
91 | } |
92 | ||
93 | /* | |
94 | * Re-calculate pending state from the set of locally pending | |
95 | * signals, globally pending signals, and blocked signals. | |
96 | */ | |
97 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
98 | { | |
99 | unsigned long ready; | |
100 | long i; | |
101 | ||
102 | switch (_NSIG_WORDS) { | |
103 | default: | |
104 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
105 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
106 | break; | |
107 | ||
108 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
109 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
110 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
111 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
112 | break; | |
113 | ||
114 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
115 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
116 | break; | |
117 | ||
118 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
119 | } | |
120 | return ready != 0; | |
121 | } | |
122 | ||
123 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
124 | ||
7bb44ade | 125 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 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 | 790 | /* |
1deac632 | 791 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 792 | */ |
ad16a460 | 793 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
794 | t = p; |
795 | do { | |
39efa3ef | 796 | task_clear_group_stop_pending(t); |
1da177e4 | 797 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); |
1deac632 | 798 | wake_up_state(t, __TASK_STOPPED); |
ad16a460 | 799 | } while_each_thread(p, t); |
1da177e4 | 800 | |
fc321d2e ON |
801 | /* |
802 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
803 | * | |
804 | * If we were in the middle of a group stop, we pretend it | |
805 | * was already finished, and then continued. Since SIGCHLD | |
806 | * doesn't queue we report only CLD_STOPPED, as if the next | |
807 | * CLD_CONTINUED was dropped. | |
808 | */ | |
809 | why = 0; | |
ad16a460 | 810 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 811 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 812 | else if (signal->group_stop_count) |
fc321d2e ON |
813 | why |= SIGNAL_CLD_STOPPED; |
814 | ||
815 | if (why) { | |
021e1ae3 | 816 | /* |
ae6d2ed7 | 817 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
818 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
819 | * notify its parent. See get_signal_to_deliver(). | |
820 | */ | |
ad16a460 ON |
821 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
822 | signal->group_stop_count = 0; | |
823 | signal->group_exit_code = 0; | |
1da177e4 LT |
824 | } else { |
825 | /* | |
826 | * We are not stopped, but there could be a stop | |
827 | * signal in the middle of being processed after | |
828 | * being removed from the queue. Clear that too. | |
829 | */ | |
ad16a460 | 830 | signal->flags &= ~SIGNAL_STOP_DEQUEUED; |
1da177e4 | 831 | } |
1da177e4 | 832 | } |
7e695a5e | 833 | |
921cf9f6 | 834 | return !sig_ignored(p, sig, from_ancestor_ns); |
1da177e4 LT |
835 | } |
836 | ||
71f11dc0 ON |
837 | /* |
838 | * Test if P wants to take SIG. After we've checked all threads with this, | |
839 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
840 | * blocking SIG were ruled out because they are not running and already | |
841 | * have pending signals. Such threads will dequeue from the shared queue | |
842 | * as soon as they're available, so putting the signal on the shared queue | |
843 | * will be equivalent to sending it to one such thread. | |
844 | */ | |
845 | static inline int wants_signal(int sig, struct task_struct *p) | |
846 | { | |
847 | if (sigismember(&p->blocked, sig)) | |
848 | return 0; | |
849 | if (p->flags & PF_EXITING) | |
850 | return 0; | |
851 | if (sig == SIGKILL) | |
852 | return 1; | |
853 | if (task_is_stopped_or_traced(p)) | |
854 | return 0; | |
855 | return task_curr(p) || !signal_pending(p); | |
856 | } | |
857 | ||
5fcd835b | 858 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
859 | { |
860 | struct signal_struct *signal = p->signal; | |
861 | struct task_struct *t; | |
862 | ||
863 | /* | |
864 | * Now find a thread we can wake up to take the signal off the queue. | |
865 | * | |
866 | * If the main thread wants the signal, it gets first crack. | |
867 | * Probably the least surprising to the average bear. | |
868 | */ | |
869 | if (wants_signal(sig, p)) | |
870 | t = p; | |
5fcd835b | 871 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
872 | /* |
873 | * There is just one thread and it does not need to be woken. | |
874 | * It will dequeue unblocked signals before it runs again. | |
875 | */ | |
876 | return; | |
877 | else { | |
878 | /* | |
879 | * Otherwise try to find a suitable thread. | |
880 | */ | |
881 | t = signal->curr_target; | |
882 | while (!wants_signal(sig, t)) { | |
883 | t = next_thread(t); | |
884 | if (t == signal->curr_target) | |
885 | /* | |
886 | * No thread needs to be woken. | |
887 | * Any eligible threads will see | |
888 | * the signal in the queue soon. | |
889 | */ | |
890 | return; | |
891 | } | |
892 | signal->curr_target = t; | |
893 | } | |
894 | ||
895 | /* | |
896 | * Found a killable thread. If the signal will be fatal, | |
897 | * then start taking the whole group down immediately. | |
898 | */ | |
fae5fa44 ON |
899 | if (sig_fatal(p, sig) && |
900 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 901 | !sigismember(&t->real_blocked, sig) && |
445a91d2 | 902 | (sig == SIGKILL || |
43918f2b | 903 | !tracehook_consider_fatal_signal(t, sig))) { |
71f11dc0 ON |
904 | /* |
905 | * This signal will be fatal to the whole group. | |
906 | */ | |
907 | if (!sig_kernel_coredump(sig)) { | |
908 | /* | |
909 | * Start a group exit and wake everybody up. | |
910 | * This way we don't have other threads | |
911 | * running and doing things after a slower | |
912 | * thread has the fatal signal pending. | |
913 | */ | |
914 | signal->flags = SIGNAL_GROUP_EXIT; | |
915 | signal->group_exit_code = sig; | |
916 | signal->group_stop_count = 0; | |
917 | t = p; | |
918 | do { | |
39efa3ef | 919 | task_clear_group_stop_pending(t); |
71f11dc0 ON |
920 | sigaddset(&t->pending.signal, SIGKILL); |
921 | signal_wake_up(t, 1); | |
922 | } while_each_thread(p, t); | |
923 | return; | |
924 | } | |
925 | } | |
926 | ||
927 | /* | |
928 | * The signal is already in the shared-pending queue. | |
929 | * Tell the chosen thread to wake up and dequeue it. | |
930 | */ | |
931 | signal_wake_up(t, sig == SIGKILL); | |
932 | return; | |
933 | } | |
934 | ||
af7fff9c PE |
935 | static inline int legacy_queue(struct sigpending *signals, int sig) |
936 | { | |
937 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
938 | } | |
939 | ||
7978b567 SB |
940 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
941 | int group, int from_ancestor_ns) | |
1da177e4 | 942 | { |
2ca3515a | 943 | struct sigpending *pending; |
6e65acba | 944 | struct sigqueue *q; |
7a0aeb14 | 945 | int override_rlimit; |
1da177e4 | 946 | |
d1eb650f | 947 | trace_signal_generate(sig, info, t); |
0a16b607 | 948 | |
6e65acba | 949 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 SB |
950 | |
951 | if (!prepare_signal(sig, t, from_ancestor_ns)) | |
7e695a5e | 952 | return 0; |
2ca3515a ON |
953 | |
954 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
955 | /* |
956 | * Short-circuit ignored signals and support queuing | |
957 | * exactly one non-rt signal, so that we can get more | |
958 | * detailed information about the cause of the signal. | |
959 | */ | |
7e695a5e | 960 | if (legacy_queue(pending, sig)) |
2acb024d | 961 | return 0; |
1da177e4 LT |
962 | /* |
963 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
964 | * or SIGKILL. | |
965 | */ | |
b67a1b9e | 966 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
967 | goto out_set; |
968 | ||
969 | /* Real-time signals must be queued if sent by sigqueue, or | |
970 | some other real-time mechanism. It is implementation | |
971 | defined whether kill() does so. We attempt to do so, on | |
972 | the principle of least surprise, but since kill is not | |
973 | allowed to fail with EAGAIN when low on memory we just | |
974 | make sure at least one signal gets delivered and don't | |
975 | pass on the info struct. */ | |
976 | ||
7a0aeb14 VN |
977 | if (sig < SIGRTMIN) |
978 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
979 | else | |
980 | override_rlimit = 0; | |
981 | ||
f84d49b2 | 982 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 983 | override_rlimit); |
1da177e4 | 984 | if (q) { |
2ca3515a | 985 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 986 | switch ((unsigned long) info) { |
b67a1b9e | 987 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
988 | q->info.si_signo = sig; |
989 | q->info.si_errno = 0; | |
990 | q->info.si_code = SI_USER; | |
9cd4fd10 | 991 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 992 | task_active_pid_ns(t)); |
76aac0e9 | 993 | q->info.si_uid = current_uid(); |
1da177e4 | 994 | break; |
b67a1b9e | 995 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
996 | q->info.si_signo = sig; |
997 | q->info.si_errno = 0; | |
998 | q->info.si_code = SI_KERNEL; | |
999 | q->info.si_pid = 0; | |
1000 | q->info.si_uid = 0; | |
1001 | break; | |
1002 | default: | |
1003 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1004 | if (from_ancestor_ns) |
1005 | q->info.si_pid = 0; | |
1da177e4 LT |
1006 | break; |
1007 | } | |
621d3121 | 1008 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1009 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1010 | /* | |
1011 | * Queue overflow, abort. We may abort if the | |
1012 | * signal was rt and sent by user using something | |
1013 | * other than kill(). | |
1014 | */ | |
1015 | trace_signal_overflow_fail(sig, group, info); | |
1da177e4 | 1016 | return -EAGAIN; |
ba005e1f MH |
1017 | } else { |
1018 | /* | |
1019 | * This is a silent loss of information. We still | |
1020 | * send the signal, but the *info bits are lost. | |
1021 | */ | |
1022 | trace_signal_lose_info(sig, group, info); | |
1023 | } | |
1da177e4 LT |
1024 | } |
1025 | ||
1026 | out_set: | |
53c30337 | 1027 | signalfd_notify(t, sig); |
2ca3515a | 1028 | sigaddset(&pending->signal, sig); |
4cd4b6d4 PE |
1029 | complete_signal(sig, t, group); |
1030 | return 0; | |
1da177e4 LT |
1031 | } |
1032 | ||
7978b567 SB |
1033 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1034 | int group) | |
1035 | { | |
921cf9f6 SB |
1036 | int from_ancestor_ns = 0; |
1037 | ||
1038 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1039 | from_ancestor_ns = si_fromuser(info) && |
1040 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1041 | #endif |
1042 | ||
1043 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1044 | } |
1045 | ||
45807a1d IM |
1046 | static void print_fatal_signal(struct pt_regs *regs, int signr) |
1047 | { | |
1048 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 1049 | current->comm, task_pid_nr(current), signr); |
45807a1d | 1050 | |
ca5cd877 | 1051 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 1052 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
1053 | { |
1054 | int i; | |
1055 | for (i = 0; i < 16; i++) { | |
1056 | unsigned char insn; | |
1057 | ||
b45c6e76 AK |
1058 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1059 | break; | |
45807a1d IM |
1060 | printk("%02x ", insn); |
1061 | } | |
1062 | } | |
1063 | #endif | |
1064 | printk("\n"); | |
3a9f84d3 | 1065 | preempt_disable(); |
45807a1d | 1066 | show_regs(regs); |
3a9f84d3 | 1067 | preempt_enable(); |
45807a1d IM |
1068 | } |
1069 | ||
1070 | static int __init setup_print_fatal_signals(char *str) | |
1071 | { | |
1072 | get_option (&str, &print_fatal_signals); | |
1073 | ||
1074 | return 1; | |
1075 | } | |
1076 | ||
1077 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1078 | |
4cd4b6d4 PE |
1079 | int |
1080 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1081 | { | |
1082 | return send_signal(sig, info, p, 1); | |
1083 | } | |
1084 | ||
1da177e4 LT |
1085 | static int |
1086 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1087 | { | |
4cd4b6d4 | 1088 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1089 | } |
1090 | ||
4a30debf ON |
1091 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1092 | bool group) | |
1093 | { | |
1094 | unsigned long flags; | |
1095 | int ret = -ESRCH; | |
1096 | ||
1097 | if (lock_task_sighand(p, &flags)) { | |
1098 | ret = send_signal(sig, info, p, group); | |
1099 | unlock_task_sighand(p, &flags); | |
1100 | } | |
1101 | ||
1102 | return ret; | |
1103 | } | |
1104 | ||
1da177e4 LT |
1105 | /* |
1106 | * Force a signal that the process can't ignore: if necessary | |
1107 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1108 | * |
1109 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1110 | * since we do not want to have a signal handler that was blocked | |
1111 | * be invoked when user space had explicitly blocked it. | |
1112 | * | |
80fe728d ON |
1113 | * We don't want to have recursive SIGSEGV's etc, for example, |
1114 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1115 | */ |
1da177e4 LT |
1116 | int |
1117 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1118 | { | |
1119 | unsigned long int flags; | |
ae74c3b6 LT |
1120 | int ret, blocked, ignored; |
1121 | struct k_sigaction *action; | |
1da177e4 LT |
1122 | |
1123 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1124 | action = &t->sighand->action[sig-1]; |
1125 | ignored = action->sa.sa_handler == SIG_IGN; | |
1126 | blocked = sigismember(&t->blocked, sig); | |
1127 | if (blocked || ignored) { | |
1128 | action->sa.sa_handler = SIG_DFL; | |
1129 | if (blocked) { | |
1130 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1131 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1132 | } |
1da177e4 | 1133 | } |
80fe728d ON |
1134 | if (action->sa.sa_handler == SIG_DFL) |
1135 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1136 | ret = specific_send_sig_info(sig, info, t); |
1137 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1138 | ||
1139 | return ret; | |
1140 | } | |
1141 | ||
1da177e4 LT |
1142 | /* |
1143 | * Nuke all other threads in the group. | |
1144 | */ | |
09faef11 | 1145 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1146 | { |
09faef11 ON |
1147 | struct task_struct *t = p; |
1148 | int count = 0; | |
1da177e4 | 1149 | |
1da177e4 LT |
1150 | p->signal->group_stop_count = 0; |
1151 | ||
09faef11 | 1152 | while_each_thread(p, t) { |
39efa3ef | 1153 | task_clear_group_stop_pending(t); |
09faef11 ON |
1154 | count++; |
1155 | ||
1156 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1157 | if (t->exit_state) |
1158 | continue; | |
1da177e4 | 1159 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1160 | signal_wake_up(t, 1); |
1161 | } | |
09faef11 ON |
1162 | |
1163 | return count; | |
1da177e4 LT |
1164 | } |
1165 | ||
b8ed374e NK |
1166 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1167 | unsigned long *flags) | |
f63ee72e ON |
1168 | { |
1169 | struct sighand_struct *sighand; | |
1170 | ||
1406f2d3 | 1171 | rcu_read_lock(); |
f63ee72e ON |
1172 | for (;;) { |
1173 | sighand = rcu_dereference(tsk->sighand); | |
1174 | if (unlikely(sighand == NULL)) | |
1175 | break; | |
1176 | ||
1177 | spin_lock_irqsave(&sighand->siglock, *flags); | |
1178 | if (likely(sighand == tsk->sighand)) | |
1179 | break; | |
1180 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
1181 | } | |
1406f2d3 | 1182 | rcu_read_unlock(); |
f63ee72e ON |
1183 | |
1184 | return sighand; | |
1185 | } | |
1186 | ||
c69e8d9c DH |
1187 | /* |
1188 | * send signal info to all the members of a group | |
c69e8d9c | 1189 | */ |
1da177e4 LT |
1190 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1191 | { | |
694f690d DH |
1192 | int ret; |
1193 | ||
1194 | rcu_read_lock(); | |
1195 | ret = check_kill_permission(sig, info, p); | |
1196 | rcu_read_unlock(); | |
f63ee72e | 1197 | |
4a30debf ON |
1198 | if (!ret && sig) |
1199 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1200 | |
1201 | return ret; | |
1202 | } | |
1203 | ||
1204 | /* | |
146a505d | 1205 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1206 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1207 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1208 | */ |
c4b92fc1 | 1209 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1210 | { |
1211 | struct task_struct *p = NULL; | |
1212 | int retval, success; | |
1213 | ||
1da177e4 LT |
1214 | success = 0; |
1215 | retval = -ESRCH; | |
c4b92fc1 | 1216 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1217 | int err = group_send_sig_info(sig, info, p); |
1218 | success |= !err; | |
1219 | retval = err; | |
c4b92fc1 | 1220 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1221 | return success ? 0 : retval; |
1222 | } | |
1223 | ||
c4b92fc1 | 1224 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1225 | { |
d36174bc | 1226 | int error = -ESRCH; |
1da177e4 LT |
1227 | struct task_struct *p; |
1228 | ||
e56d0903 | 1229 | rcu_read_lock(); |
d36174bc | 1230 | retry: |
c4b92fc1 | 1231 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1232 | if (p) { |
1da177e4 | 1233 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1234 | if (unlikely(error == -ESRCH)) |
1235 | /* | |
1236 | * The task was unhashed in between, try again. | |
1237 | * If it is dead, pid_task() will return NULL, | |
1238 | * if we race with de_thread() it will find the | |
1239 | * new leader. | |
1240 | */ | |
1241 | goto retry; | |
1242 | } | |
e56d0903 | 1243 | rcu_read_unlock(); |
6ca25b55 | 1244 | |
1da177e4 LT |
1245 | return error; |
1246 | } | |
1247 | ||
c3de4b38 MW |
1248 | int |
1249 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
c4b92fc1 EB |
1250 | { |
1251 | int error; | |
1252 | rcu_read_lock(); | |
b488893a | 1253 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1254 | rcu_read_unlock(); |
1255 | return error; | |
1256 | } | |
1257 | ||
2425c08b EB |
1258 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1259 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1260 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1261 | { |
1262 | int ret = -EINVAL; | |
1263 | struct task_struct *p; | |
c69e8d9c | 1264 | const struct cred *pcred; |
14d8c9f3 | 1265 | unsigned long flags; |
46113830 HW |
1266 | |
1267 | if (!valid_signal(sig)) | |
1268 | return ret; | |
1269 | ||
14d8c9f3 | 1270 | rcu_read_lock(); |
2425c08b | 1271 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1272 | if (!p) { |
1273 | ret = -ESRCH; | |
1274 | goto out_unlock; | |
1275 | } | |
c69e8d9c | 1276 | pcred = __task_cred(p); |
614c517d | 1277 | if (si_fromuser(info) && |
c69e8d9c DH |
1278 | euid != pcred->suid && euid != pcred->uid && |
1279 | uid != pcred->suid && uid != pcred->uid) { | |
46113830 HW |
1280 | ret = -EPERM; |
1281 | goto out_unlock; | |
1282 | } | |
8f95dc58 DQ |
1283 | ret = security_task_kill(p, info, sig, secid); |
1284 | if (ret) | |
1285 | goto out_unlock; | |
14d8c9f3 TG |
1286 | |
1287 | if (sig) { | |
1288 | if (lock_task_sighand(p, &flags)) { | |
1289 | ret = __send_signal(sig, info, p, 1, 0); | |
1290 | unlock_task_sighand(p, &flags); | |
1291 | } else | |
1292 | ret = -ESRCH; | |
46113830 HW |
1293 | } |
1294 | out_unlock: | |
14d8c9f3 | 1295 | rcu_read_unlock(); |
46113830 HW |
1296 | return ret; |
1297 | } | |
2425c08b | 1298 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1299 | |
1300 | /* | |
1301 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1302 | * | |
1303 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1304 | * is probably wrong. Should make it like BSD or SYSV. | |
1305 | */ | |
1306 | ||
bc64efd2 | 1307 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1308 | { |
8d42db18 | 1309 | int ret; |
d5df763b PE |
1310 | |
1311 | if (pid > 0) { | |
1312 | rcu_read_lock(); | |
1313 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1314 | rcu_read_unlock(); | |
1315 | return ret; | |
1316 | } | |
1317 | ||
1318 | read_lock(&tasklist_lock); | |
1319 | if (pid != -1) { | |
1320 | ret = __kill_pgrp_info(sig, info, | |
1321 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1322 | } else { | |
1da177e4 LT |
1323 | int retval = 0, count = 0; |
1324 | struct task_struct * p; | |
1325 | ||
1da177e4 | 1326 | for_each_process(p) { |
d25141a8 SB |
1327 | if (task_pid_vnr(p) > 1 && |
1328 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1329 | int err = group_send_sig_info(sig, info, p); |
1330 | ++count; | |
1331 | if (err != -EPERM) | |
1332 | retval = err; | |
1333 | } | |
1334 | } | |
8d42db18 | 1335 | ret = count ? retval : -ESRCH; |
1da177e4 | 1336 | } |
d5df763b PE |
1337 | read_unlock(&tasklist_lock); |
1338 | ||
8d42db18 | 1339 | return ret; |
1da177e4 LT |
1340 | } |
1341 | ||
1342 | /* | |
1343 | * These are for backward compatibility with the rest of the kernel source. | |
1344 | */ | |
1345 | ||
1da177e4 LT |
1346 | int |
1347 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1348 | { | |
1da177e4 LT |
1349 | /* |
1350 | * Make sure legacy kernel users don't send in bad values | |
1351 | * (normal paths check this in check_kill_permission). | |
1352 | */ | |
7ed20e1a | 1353 | if (!valid_signal(sig)) |
1da177e4 LT |
1354 | return -EINVAL; |
1355 | ||
4a30debf | 1356 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1357 | } |
1358 | ||
b67a1b9e ON |
1359 | #define __si_special(priv) \ |
1360 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1361 | ||
1da177e4 LT |
1362 | int |
1363 | send_sig(int sig, struct task_struct *p, int priv) | |
1364 | { | |
b67a1b9e | 1365 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1366 | } |
1367 | ||
1da177e4 LT |
1368 | void |
1369 | force_sig(int sig, struct task_struct *p) | |
1370 | { | |
b67a1b9e | 1371 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1372 | } |
1373 | ||
1374 | /* | |
1375 | * When things go south during signal handling, we | |
1376 | * will force a SIGSEGV. And if the signal that caused | |
1377 | * the problem was already a SIGSEGV, we'll want to | |
1378 | * make sure we don't even try to deliver the signal.. | |
1379 | */ | |
1380 | int | |
1381 | force_sigsegv(int sig, struct task_struct *p) | |
1382 | { | |
1383 | if (sig == SIGSEGV) { | |
1384 | unsigned long flags; | |
1385 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1386 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1387 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1388 | } | |
1389 | force_sig(SIGSEGV, p); | |
1390 | return 0; | |
1391 | } | |
1392 | ||
c4b92fc1 EB |
1393 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1394 | { | |
146a505d PE |
1395 | int ret; |
1396 | ||
1397 | read_lock(&tasklist_lock); | |
1398 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1399 | read_unlock(&tasklist_lock); | |
1400 | ||
1401 | return ret; | |
c4b92fc1 EB |
1402 | } |
1403 | EXPORT_SYMBOL(kill_pgrp); | |
1404 | ||
1405 | int kill_pid(struct pid *pid, int sig, int priv) | |
1406 | { | |
1407 | return kill_pid_info(sig, __si_special(priv), pid); | |
1408 | } | |
1409 | EXPORT_SYMBOL(kill_pid); | |
1410 | ||
1da177e4 LT |
1411 | /* |
1412 | * These functions support sending signals using preallocated sigqueue | |
1413 | * structures. This is needed "because realtime applications cannot | |
1414 | * afford to lose notifications of asynchronous events, like timer | |
f84d49b2 | 1415 | * expirations or I/O completions". In the case of Posix Timers |
1da177e4 LT |
1416 | * we allocate the sigqueue structure from the timer_create. If this |
1417 | * allocation fails we are able to report the failure to the application | |
1418 | * with an EAGAIN error. | |
1419 | */ | |
1da177e4 LT |
1420 | struct sigqueue *sigqueue_alloc(void) |
1421 | { | |
f84d49b2 | 1422 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1423 | |
f84d49b2 | 1424 | if (q) |
1da177e4 | 1425 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1426 | |
1427 | return q; | |
1da177e4 LT |
1428 | } |
1429 | ||
1430 | void sigqueue_free(struct sigqueue *q) | |
1431 | { | |
1432 | unsigned long flags; | |
60187d27 ON |
1433 | spinlock_t *lock = ¤t->sighand->siglock; |
1434 | ||
1da177e4 LT |
1435 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1436 | /* | |
c8e85b4f ON |
1437 | * We must hold ->siglock while testing q->list |
1438 | * to serialize with collect_signal() or with | |
da7978b0 | 1439 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1440 | */ |
60187d27 | 1441 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1442 | q->flags &= ~SIGQUEUE_PREALLOC; |
1443 | /* | |
1444 | * If it is queued it will be freed when dequeued, | |
1445 | * like the "regular" sigqueue. | |
1446 | */ | |
60187d27 | 1447 | if (!list_empty(&q->list)) |
c8e85b4f | 1448 | q = NULL; |
60187d27 ON |
1449 | spin_unlock_irqrestore(lock, flags); |
1450 | ||
c8e85b4f ON |
1451 | if (q) |
1452 | __sigqueue_free(q); | |
1da177e4 LT |
1453 | } |
1454 | ||
ac5c2153 | 1455 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1456 | { |
e62e6650 | 1457 | int sig = q->info.si_signo; |
2ca3515a | 1458 | struct sigpending *pending; |
e62e6650 ON |
1459 | unsigned long flags; |
1460 | int ret; | |
2ca3515a | 1461 | |
4cd4b6d4 | 1462 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1463 | |
1464 | ret = -1; | |
1465 | if (!likely(lock_task_sighand(t, &flags))) | |
1466 | goto ret; | |
1467 | ||
7e695a5e | 1468 | ret = 1; /* the signal is ignored */ |
921cf9f6 | 1469 | if (!prepare_signal(sig, t, 0)) |
e62e6650 ON |
1470 | goto out; |
1471 | ||
1472 | ret = 0; | |
9e3bd6c3 PE |
1473 | if (unlikely(!list_empty(&q->list))) { |
1474 | /* | |
1475 | * If an SI_TIMER entry is already queue just increment | |
1476 | * the overrun count. | |
1477 | */ | |
9e3bd6c3 PE |
1478 | BUG_ON(q->info.si_code != SI_TIMER); |
1479 | q->info.si_overrun++; | |
e62e6650 | 1480 | goto out; |
9e3bd6c3 | 1481 | } |
ba661292 | 1482 | q->info.si_overrun = 0; |
9e3bd6c3 | 1483 | |
9e3bd6c3 | 1484 | signalfd_notify(t, sig); |
2ca3515a | 1485 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1486 | list_add_tail(&q->list, &pending->list); |
1487 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1488 | complete_signal(sig, t, group); |
e62e6650 ON |
1489 | out: |
1490 | unlock_task_sighand(t, &flags); | |
1491 | ret: | |
1492 | return ret; | |
9e3bd6c3 PE |
1493 | } |
1494 | ||
1da177e4 LT |
1495 | /* |
1496 | * Let a parent know about the death of a child. | |
1497 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 RM |
1498 | * |
1499 | * Returns -1 if our parent ignored us and so we've switched to | |
1500 | * self-reaping, or else @sig. | |
1da177e4 | 1501 | */ |
2b2a1ff6 | 1502 | int do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1503 | { |
1504 | struct siginfo info; | |
1505 | unsigned long flags; | |
1506 | struct sighand_struct *psig; | |
1b04624f | 1507 | int ret = sig; |
1da177e4 LT |
1508 | |
1509 | BUG_ON(sig == -1); | |
1510 | ||
1511 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1512 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1513 | |
5cb11446 | 1514 | BUG_ON(!task_ptrace(tsk) && |
1da177e4 LT |
1515 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1516 | ||
1517 | info.si_signo = sig; | |
1518 | info.si_errno = 0; | |
b488893a PE |
1519 | /* |
1520 | * we are under tasklist_lock here so our parent is tied to | |
1521 | * us and cannot exit and release its namespace. | |
1522 | * | |
1523 | * the only it can is to switch its nsproxy with sys_unshare, | |
1524 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1525 | * see relevant namespace | |
1526 | * | |
1527 | * write_lock() currently calls preempt_disable() which is the | |
1528 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1529 | * correct to rely on this | |
1530 | */ | |
1531 | rcu_read_lock(); | |
1532 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
c69e8d9c | 1533 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1534 | rcu_read_unlock(); |
1535 | ||
32bd671d PZ |
1536 | info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime, |
1537 | tsk->signal->utime)); | |
1538 | info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime, | |
1539 | tsk->signal->stime)); | |
1da177e4 LT |
1540 | |
1541 | info.si_status = tsk->exit_code & 0x7f; | |
1542 | if (tsk->exit_code & 0x80) | |
1543 | info.si_code = CLD_DUMPED; | |
1544 | else if (tsk->exit_code & 0x7f) | |
1545 | info.si_code = CLD_KILLED; | |
1546 | else { | |
1547 | info.si_code = CLD_EXITED; | |
1548 | info.si_status = tsk->exit_code >> 8; | |
1549 | } | |
1550 | ||
1551 | psig = tsk->parent->sighand; | |
1552 | spin_lock_irqsave(&psig->siglock, flags); | |
5cb11446 | 1553 | if (!task_ptrace(tsk) && sig == SIGCHLD && |
1da177e4 LT |
1554 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1555 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1556 | /* | |
1557 | * We are exiting and our parent doesn't care. POSIX.1 | |
1558 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1559 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1560 | * automatically and not left for our parent's wait4 call. | |
1561 | * Rather than having the parent do it as a magic kind of | |
1562 | * signal handler, we just set this to tell do_exit that we | |
1563 | * can be cleaned up without becoming a zombie. Note that | |
1564 | * we still call __wake_up_parent in this case, because a | |
1565 | * blocked sys_wait4 might now return -ECHILD. | |
1566 | * | |
1567 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1568 | * is implementation-defined: we do (if you don't want | |
1569 | * it, just use SIG_IGN instead). | |
1570 | */ | |
1b04624f | 1571 | ret = tsk->exit_signal = -1; |
1da177e4 | 1572 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
2b2a1ff6 | 1573 | sig = -1; |
1da177e4 | 1574 | } |
7ed20e1a | 1575 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1576 | __group_send_sig_info(sig, &info, tsk->parent); |
1577 | __wake_up_parent(tsk, tsk->parent); | |
1578 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1579 | |
1b04624f | 1580 | return ret; |
1da177e4 LT |
1581 | } |
1582 | ||
75b95953 TH |
1583 | /** |
1584 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1585 | * @tsk: task reporting the state change | |
1586 | * @for_ptracer: the notification is for ptracer | |
1587 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1588 | * | |
1589 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1590 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1591 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1592 | * | |
1593 | * CONTEXT: | |
1594 | * Must be called with tasklist_lock at least read locked. | |
1595 | */ | |
1596 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1597 | bool for_ptracer, int why) | |
1da177e4 LT |
1598 | { |
1599 | struct siginfo info; | |
1600 | unsigned long flags; | |
bc505a47 | 1601 | struct task_struct *parent; |
1da177e4 LT |
1602 | struct sighand_struct *sighand; |
1603 | ||
75b95953 | 1604 | if (for_ptracer) { |
bc505a47 | 1605 | parent = tsk->parent; |
75b95953 | 1606 | } else { |
bc505a47 ON |
1607 | tsk = tsk->group_leader; |
1608 | parent = tsk->real_parent; | |
1609 | } | |
1610 | ||
1da177e4 LT |
1611 | info.si_signo = SIGCHLD; |
1612 | info.si_errno = 0; | |
b488893a PE |
1613 | /* |
1614 | * see comment in do_notify_parent() abot the following 3 lines | |
1615 | */ | |
1616 | rcu_read_lock(); | |
d9265663 | 1617 | info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns); |
c69e8d9c | 1618 | info.si_uid = __task_cred(tsk)->uid; |
b488893a PE |
1619 | rcu_read_unlock(); |
1620 | ||
d8878ba3 MK |
1621 | info.si_utime = cputime_to_clock_t(tsk->utime); |
1622 | info.si_stime = cputime_to_clock_t(tsk->stime); | |
1da177e4 LT |
1623 | |
1624 | info.si_code = why; | |
1625 | switch (why) { | |
1626 | case CLD_CONTINUED: | |
1627 | info.si_status = SIGCONT; | |
1628 | break; | |
1629 | case CLD_STOPPED: | |
1630 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1631 | break; | |
1632 | case CLD_TRAPPED: | |
1633 | info.si_status = tsk->exit_code & 0x7f; | |
1634 | break; | |
1635 | default: | |
1636 | BUG(); | |
1637 | } | |
1638 | ||
1639 | sighand = parent->sighand; | |
1640 | spin_lock_irqsave(&sighand->siglock, flags); | |
1641 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1642 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1643 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1644 | /* | |
1645 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1646 | */ | |
1647 | __wake_up_parent(tsk, parent); | |
1648 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1649 | } | |
1650 | ||
d5f70c00 ON |
1651 | static inline int may_ptrace_stop(void) |
1652 | { | |
5cb11446 | 1653 | if (!likely(task_ptrace(current))) |
d5f70c00 | 1654 | return 0; |
d5f70c00 ON |
1655 | /* |
1656 | * Are we in the middle of do_coredump? | |
1657 | * If so and our tracer is also part of the coredump stopping | |
1658 | * is a deadlock situation, and pointless because our tracer | |
1659 | * is dead so don't allow us to stop. | |
1660 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1661 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 ON |
1662 | * is safe to enter schedule(). |
1663 | */ | |
999d9fc1 | 1664 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1665 | unlikely(current->mm == current->parent->mm)) |
1666 | return 0; | |
1667 | ||
1668 | return 1; | |
1669 | } | |
1670 | ||
1a669c2f RM |
1671 | /* |
1672 | * Return nonzero if there is a SIGKILL that should be waking us up. | |
1673 | * Called with the siglock held. | |
1674 | */ | |
1675 | static int sigkill_pending(struct task_struct *tsk) | |
1676 | { | |
3d749b9e ON |
1677 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1678 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1679 | } |
1680 | ||
ceb6bd67 TH |
1681 | /* |
1682 | * Test whether the target task of the usual cldstop notification - the | |
1683 | * real_parent of @child - is in the same group as the ptracer. | |
1684 | */ | |
1685 | static bool real_parent_is_ptracer(struct task_struct *child) | |
1686 | { | |
1687 | return same_thread_group(child->parent, child->real_parent); | |
1688 | } | |
1689 | ||
1da177e4 LT |
1690 | /* |
1691 | * This must be called with current->sighand->siglock held. | |
1692 | * | |
1693 | * This should be the path for all ptrace stops. | |
1694 | * We always set current->last_siginfo while stopped here. | |
1695 | * That makes it a way to test a stopped process for | |
1696 | * being ptrace-stopped vs being job-control-stopped. | |
1697 | * | |
20686a30 ON |
1698 | * If we actually decide not to stop at all because the tracer |
1699 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1700 | */ |
fe1bc6a0 | 1701 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1702 | __releases(¤t->sighand->siglock) |
1703 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1704 | { |
ceb6bd67 TH |
1705 | bool gstop_done = false; |
1706 | ||
1a669c2f RM |
1707 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1708 | /* | |
1709 | * The arch code has something special to do before a | |
1710 | * ptrace stop. This is allowed to block, e.g. for faults | |
1711 | * on user stack pages. We can't keep the siglock while | |
1712 | * calling arch_ptrace_stop, so we must release it now. | |
1713 | * To preserve proper semantics, we must do this before | |
1714 | * any signal bookkeeping like checking group_stop_count. | |
1715 | * Meanwhile, a SIGKILL could come in before we retake the | |
1716 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1717 | * So after regaining the lock, we must check for SIGKILL. | |
1718 | */ | |
1719 | spin_unlock_irq(¤t->sighand->siglock); | |
1720 | arch_ptrace_stop(exit_code, info); | |
1721 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1722 | if (sigkill_pending(current)) |
1723 | return; | |
1a669c2f RM |
1724 | } |
1725 | ||
1da177e4 | 1726 | /* |
0ae8ce1c TH |
1727 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1728 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
1729 | * while siglock was released for the arch hook, PENDING could be | |
1730 | * clear now. We act as if SIGCONT is received after TASK_TRACED | |
1731 | * is entered - ignore it. | |
1da177e4 | 1732 | */ |
0ae8ce1c | 1733 | if (why == CLD_STOPPED && (current->group_stop & GROUP_STOP_PENDING)) |
ceb6bd67 | 1734 | gstop_done = task_participate_group_stop(current); |
1da177e4 LT |
1735 | |
1736 | current->last_siginfo = info; | |
1737 | current->exit_code = exit_code; | |
1738 | ||
d79fdd6d TH |
1739 | /* |
1740 | * TRACED should be visible before TRAPPING is cleared; otherwise, | |
1741 | * the tracer might fail do_wait(). | |
1742 | */ | |
1743 | set_current_state(TASK_TRACED); | |
1744 | ||
1745 | /* | |
1746 | * We're committing to trapping. Clearing GROUP_STOP_TRAPPING and | |
1747 | * transition to TASK_TRACED should be atomic with respect to | |
1748 | * siglock. This hsould be done after the arch hook as siglock is | |
1749 | * released and regrabbed across it. | |
1750 | */ | |
1751 | task_clear_group_stop_trapping(current); | |
1752 | ||
1da177e4 LT |
1753 | spin_unlock_irq(¤t->sighand->siglock); |
1754 | read_lock(&tasklist_lock); | |
3d749b9e | 1755 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1756 | /* |
1757 | * Notify parents of the stop. | |
1758 | * | |
1759 | * While ptraced, there are two parents - the ptracer and | |
1760 | * the real_parent of the group_leader. The ptracer should | |
1761 | * know about every stop while the real parent is only | |
1762 | * interested in the completion of group stop. The states | |
1763 | * for the two don't interact with each other. Notify | |
1764 | * separately unless they're gonna be duplicates. | |
1765 | */ | |
1766 | do_notify_parent_cldstop(current, true, why); | |
1767 | if (gstop_done && !real_parent_is_ptracer(current)) | |
1768 | do_notify_parent_cldstop(current, false, why); | |
1769 | ||
53da1d94 MS |
1770 | /* |
1771 | * Don't want to allow preemption here, because | |
1772 | * sys_ptrace() needs this task to be inactive. | |
1773 | * | |
1774 | * XXX: implement read_unlock_no_resched(). | |
1775 | */ | |
1776 | preempt_disable(); | |
1da177e4 | 1777 | read_unlock(&tasklist_lock); |
53da1d94 | 1778 | preempt_enable_no_resched(); |
1da177e4 LT |
1779 | schedule(); |
1780 | } else { | |
1781 | /* | |
1782 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1783 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1784 | * |
1785 | * If @gstop_done, the ptracer went away between group stop | |
1786 | * completion and here. During detach, it would have set | |
1787 | * GROUP_STOP_PENDING on us and we'll re-enter TASK_STOPPED | |
1788 | * in do_signal_stop() on return, so notifying the real | |
1789 | * parent of the group stop completion is enough. | |
1da177e4 | 1790 | */ |
ceb6bd67 TH |
1791 | if (gstop_done) |
1792 | do_notify_parent_cldstop(current, false, why); | |
1793 | ||
6405f7f4 | 1794 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1795 | if (clear_code) |
1796 | current->exit_code = 0; | |
6405f7f4 | 1797 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1798 | } |
1799 | ||
13b1c3d4 RM |
1800 | /* |
1801 | * While in TASK_TRACED, we were considered "frozen enough". | |
1802 | * Now that we woke up, it's crucial if we're supposed to be | |
1803 | * frozen that we freeze now before running anything substantial. | |
1804 | */ | |
1805 | try_to_freeze(); | |
1806 | ||
1da177e4 LT |
1807 | /* |
1808 | * We are back. Now reacquire the siglock before touching | |
1809 | * last_siginfo, so that we are sure to have synchronized with | |
1810 | * any signal-sending on another CPU that wants to examine it. | |
1811 | */ | |
1812 | spin_lock_irq(¤t->sighand->siglock); | |
1813 | current->last_siginfo = NULL; | |
1814 | ||
1815 | /* | |
1816 | * Queued signals ignored us while we were stopped for tracing. | |
1817 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1818 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1819 | */ |
b74d0deb | 1820 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1821 | } |
1822 | ||
1823 | void ptrace_notify(int exit_code) | |
1824 | { | |
1825 | siginfo_t info; | |
1826 | ||
1827 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1828 | ||
1829 | memset(&info, 0, sizeof info); | |
1830 | info.si_signo = SIGTRAP; | |
1831 | info.si_code = exit_code; | |
b488893a | 1832 | info.si_pid = task_pid_vnr(current); |
76aac0e9 | 1833 | info.si_uid = current_uid(); |
1da177e4 LT |
1834 | |
1835 | /* Let the debugger run. */ | |
1836 | spin_lock_irq(¤t->sighand->siglock); | |
fe1bc6a0 | 1837 | ptrace_stop(exit_code, CLD_TRAPPED, 1, &info); |
1da177e4 LT |
1838 | spin_unlock_irq(¤t->sighand->siglock); |
1839 | } | |
1840 | ||
1da177e4 LT |
1841 | /* |
1842 | * This performs the stopping for SIGSTOP and other stop signals. | |
1843 | * We have to stop all threads in the thread group. | |
1844 | * Returns nonzero if we've actually stopped and released the siglock. | |
1845 | * Returns zero if we didn't stop and still hold the siglock. | |
1846 | */ | |
a122b341 | 1847 | static int do_signal_stop(int signr) |
1da177e4 LT |
1848 | { |
1849 | struct signal_struct *sig = current->signal; | |
1da177e4 | 1850 | |
39efa3ef TH |
1851 | if (!(current->group_stop & GROUP_STOP_PENDING)) { |
1852 | unsigned int gstop = GROUP_STOP_PENDING | GROUP_STOP_CONSUME; | |
f558b7e4 ON |
1853 | struct task_struct *t; |
1854 | ||
d79fdd6d TH |
1855 | /* signr will be recorded in task->group_stop for retries */ |
1856 | WARN_ON_ONCE(signr & ~GROUP_STOP_SIGMASK); | |
1857 | ||
2b201a9e | 1858 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) || |
573cf9ad | 1859 | unlikely(signal_group_exit(sig))) |
f558b7e4 | 1860 | return 0; |
1da177e4 | 1861 | /* |
408a37de TH |
1862 | * There is no group stop already in progress. We must |
1863 | * initiate one now. | |
1864 | * | |
1865 | * While ptraced, a task may be resumed while group stop is | |
1866 | * still in effect and then receive a stop signal and | |
1867 | * initiate another group stop. This deviates from the | |
1868 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
1869 | * cause two group stops when !ptraced. That is why we |
1870 | * also check !task_is_stopped(t) below. | |
408a37de TH |
1871 | * |
1872 | * The condition can be distinguished by testing whether | |
1873 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
1874 | * group_exit_code in such case. | |
1875 | * | |
1876 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
1877 | * an intervening stop signal is required to cause two | |
1878 | * continued events regardless of ptrace. | |
1da177e4 | 1879 | */ |
408a37de TH |
1880 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
1881 | sig->group_exit_code = signr; | |
1882 | else | |
1883 | WARN_ON_ONCE(!task_ptrace(current)); | |
1da177e4 | 1884 | |
d79fdd6d TH |
1885 | current->group_stop &= ~GROUP_STOP_SIGMASK; |
1886 | current->group_stop |= signr | gstop; | |
ae6d2ed7 | 1887 | sig->group_stop_count = 1; |
d79fdd6d TH |
1888 | for (t = next_thread(current); t != current; |
1889 | t = next_thread(t)) { | |
1890 | t->group_stop &= ~GROUP_STOP_SIGMASK; | |
1da177e4 | 1891 | /* |
a122b341 ON |
1892 | * Setting state to TASK_STOPPED for a group |
1893 | * stop is always done with the siglock held, | |
1894 | * so this check has no races. | |
1da177e4 | 1895 | */ |
39efa3ef | 1896 | if (!(t->flags & PF_EXITING) && !task_is_stopped(t)) { |
d79fdd6d | 1897 | t->group_stop |= signr | gstop; |
ae6d2ed7 | 1898 | sig->group_stop_count++; |
a122b341 | 1899 | signal_wake_up(t, 0); |
d79fdd6d TH |
1900 | } |
1901 | } | |
1da177e4 | 1902 | } |
d79fdd6d | 1903 | retry: |
5224fa36 TH |
1904 | if (likely(!task_ptrace(current))) { |
1905 | int notify = 0; | |
1da177e4 | 1906 | |
5224fa36 TH |
1907 | /* |
1908 | * If there are no other threads in the group, or if there | |
1909 | * is a group stop in progress and we are the last to stop, | |
1910 | * report to the parent. | |
1911 | */ | |
1912 | if (task_participate_group_stop(current)) | |
1913 | notify = CLD_STOPPED; | |
1914 | ||
d79fdd6d | 1915 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
1916 | spin_unlock_irq(¤t->sighand->siglock); |
1917 | ||
62bcf9d9 TH |
1918 | /* |
1919 | * Notify the parent of the group stop completion. Because | |
1920 | * we're not holding either the siglock or tasklist_lock | |
1921 | * here, ptracer may attach inbetween; however, this is for | |
1922 | * group stop and should always be delivered to the real | |
1923 | * parent of the group leader. The new ptracer will get | |
1924 | * its notification when this task transitions into | |
1925 | * TASK_TRACED. | |
1926 | */ | |
5224fa36 TH |
1927 | if (notify) { |
1928 | read_lock(&tasklist_lock); | |
62bcf9d9 | 1929 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
1930 | read_unlock(&tasklist_lock); |
1931 | } | |
1932 | ||
1933 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
1934 | schedule(); | |
1935 | ||
1936 | spin_lock_irq(¤t->sighand->siglock); | |
d79fdd6d TH |
1937 | } else { |
1938 | ptrace_stop(current->group_stop & GROUP_STOP_SIGMASK, | |
1939 | CLD_STOPPED, 0, NULL); | |
1940 | current->exit_code = 0; | |
1941 | } | |
1942 | ||
1943 | /* | |
1944 | * GROUP_STOP_PENDING could be set if another group stop has | |
1945 | * started since being woken up or ptrace wants us to transit | |
1946 | * between TASK_STOPPED and TRACED. Retry group stop. | |
1947 | */ | |
1948 | if (current->group_stop & GROUP_STOP_PENDING) { | |
1949 | WARN_ON_ONCE(!(current->group_stop & GROUP_STOP_SIGMASK)); | |
1950 | goto retry; | |
1951 | } | |
1952 | ||
1953 | /* PTRACE_ATTACH might have raced with task killing, clear trapping */ | |
1954 | task_clear_group_stop_trapping(current); | |
ae6d2ed7 | 1955 | |
5224fa36 | 1956 | spin_unlock_irq(¤t->sighand->siglock); |
ae6d2ed7 RM |
1957 | |
1958 | tracehook_finish_jctl(); | |
dac27f4a | 1959 | |
1da177e4 LT |
1960 | return 1; |
1961 | } | |
1962 | ||
18c98b65 RM |
1963 | static int ptrace_signal(int signr, siginfo_t *info, |
1964 | struct pt_regs *regs, void *cookie) | |
1965 | { | |
5cb11446 | 1966 | if (!task_ptrace(current)) |
18c98b65 RM |
1967 | return signr; |
1968 | ||
1969 | ptrace_signal_deliver(regs, cookie); | |
1970 | ||
1971 | /* Let the debugger run. */ | |
fe1bc6a0 | 1972 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
1973 | |
1974 | /* We're back. Did the debugger cancel the sig? */ | |
1975 | signr = current->exit_code; | |
1976 | if (signr == 0) | |
1977 | return signr; | |
1978 | ||
1979 | current->exit_code = 0; | |
1980 | ||
1981 | /* Update the siginfo structure if the signal has | |
1982 | changed. If the debugger wanted something | |
1983 | specific in the siginfo structure then it should | |
1984 | have updated *info via PTRACE_SETSIGINFO. */ | |
1985 | if (signr != info->si_signo) { | |
1986 | info->si_signo = signr; | |
1987 | info->si_errno = 0; | |
1988 | info->si_code = SI_USER; | |
1989 | info->si_pid = task_pid_vnr(current->parent); | |
c69e8d9c | 1990 | info->si_uid = task_uid(current->parent); |
18c98b65 RM |
1991 | } |
1992 | ||
1993 | /* If the (new) signal is now blocked, requeue it. */ | |
1994 | if (sigismember(¤t->blocked, signr)) { | |
1995 | specific_send_sig_info(signr, info, current); | |
1996 | signr = 0; | |
1997 | } | |
1998 | ||
1999 | return signr; | |
2000 | } | |
2001 | ||
1da177e4 LT |
2002 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
2003 | struct pt_regs *regs, void *cookie) | |
2004 | { | |
f6b76d4f ON |
2005 | struct sighand_struct *sighand = current->sighand; |
2006 | struct signal_struct *signal = current->signal; | |
2007 | int signr; | |
1da177e4 | 2008 | |
13b1c3d4 RM |
2009 | relock: |
2010 | /* | |
2011 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
2012 | * While in TASK_STOPPED, we were considered "frozen enough". | |
2013 | * Now that we woke up, it's crucial if we're supposed to be | |
2014 | * frozen that we freeze now before running anything substantial. | |
2015 | */ | |
fc558a74 RW |
2016 | try_to_freeze(); |
2017 | ||
f6b76d4f | 2018 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2019 | /* |
2020 | * Every stopped thread goes here after wakeup. Check to see if | |
2021 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2022 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2023 | */ | |
f6b76d4f | 2024 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
75b95953 | 2025 | struct task_struct *leader; |
c672af35 TH |
2026 | int why; |
2027 | ||
2028 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2029 | why = CLD_CONTINUED; | |
2030 | else | |
2031 | why = CLD_STOPPED; | |
2032 | ||
f6b76d4f | 2033 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2034 | |
ae6d2ed7 | 2035 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2036 | |
ceb6bd67 TH |
2037 | /* |
2038 | * Notify the parent that we're continuing. This event is | |
2039 | * always per-process and doesn't make whole lot of sense | |
2040 | * for ptracers, who shouldn't consume the state via | |
2041 | * wait(2) either, but, for backward compatibility, notify | |
2042 | * the ptracer of the group leader too unless it's gonna be | |
2043 | * a duplicate. | |
2044 | */ | |
edf2ed15 | 2045 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2046 | |
2047 | do_notify_parent_cldstop(current, false, why); | |
2048 | ||
75b95953 | 2049 | leader = current->group_leader; |
ceb6bd67 TH |
2050 | if (task_ptrace(leader) && !real_parent_is_ptracer(leader)) |
2051 | do_notify_parent_cldstop(leader, true, why); | |
2052 | ||
edf2ed15 | 2053 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2054 | |
e4420551 ON |
2055 | goto relock; |
2056 | } | |
2057 | ||
1da177e4 LT |
2058 | for (;;) { |
2059 | struct k_sigaction *ka; | |
7bcf6a2c RM |
2060 | /* |
2061 | * Tracing can induce an artifical signal and choose sigaction. | |
2062 | * The return value in @signr determines the default action, | |
2063 | * but @info->si_signo is the signal number we will report. | |
2064 | */ | |
2065 | signr = tracehook_get_signal(current, regs, info, return_ka); | |
2066 | if (unlikely(signr < 0)) | |
2067 | goto relock; | |
2068 | if (unlikely(signr != 0)) | |
2069 | ka = return_ka; | |
2070 | else { | |
39efa3ef TH |
2071 | if (unlikely(current->group_stop & |
2072 | GROUP_STOP_PENDING) && do_signal_stop(0)) | |
1be53963 ON |
2073 | goto relock; |
2074 | ||
7bcf6a2c RM |
2075 | signr = dequeue_signal(current, ¤t->blocked, |
2076 | info); | |
1da177e4 | 2077 | |
18c98b65 | 2078 | if (!signr) |
7bcf6a2c RM |
2079 | break; /* will return 0 */ |
2080 | ||
2081 | if (signr != SIGKILL) { | |
2082 | signr = ptrace_signal(signr, info, | |
2083 | regs, cookie); | |
2084 | if (!signr) | |
2085 | continue; | |
2086 | } | |
2087 | ||
2088 | ka = &sighand->action[signr-1]; | |
1da177e4 LT |
2089 | } |
2090 | ||
f9d4257e MH |
2091 | /* Trace actually delivered signals. */ |
2092 | trace_signal_deliver(signr, info, ka); | |
2093 | ||
1da177e4 LT |
2094 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2095 | continue; | |
2096 | if (ka->sa.sa_handler != SIG_DFL) { | |
2097 | /* Run the handler. */ | |
2098 | *return_ka = *ka; | |
2099 | ||
2100 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2101 | ka->sa.sa_handler = SIG_DFL; | |
2102 | ||
2103 | break; /* will return non-zero "signr" value */ | |
2104 | } | |
2105 | ||
2106 | /* | |
2107 | * Now we are doing the default action for this signal. | |
2108 | */ | |
2109 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2110 | continue; | |
2111 | ||
84d73786 | 2112 | /* |
0fbc26a6 | 2113 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2114 | * Container-init gets no signals it doesn't want from same |
2115 | * container. | |
2116 | * | |
2117 | * Note that if global/container-init sees a sig_kernel_only() | |
2118 | * signal here, the signal must have been generated internally | |
2119 | * or must have come from an ancestor namespace. In either | |
2120 | * case, the signal cannot be dropped. | |
84d73786 | 2121 | */ |
fae5fa44 | 2122 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2123 | !sig_kernel_only(signr)) |
1da177e4 LT |
2124 | continue; |
2125 | ||
2126 | if (sig_kernel_stop(signr)) { | |
2127 | /* | |
2128 | * The default action is to stop all threads in | |
2129 | * the thread group. The job control signals | |
2130 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2131 | * always works. Note that siglock needs to be | |
2132 | * dropped during the call to is_orphaned_pgrp() | |
2133 | * because of lock ordering with tasklist_lock. | |
2134 | * This allows an intervening SIGCONT to be posted. | |
2135 | * We need to check for that and bail out if necessary. | |
2136 | */ | |
2137 | if (signr != SIGSTOP) { | |
f6b76d4f | 2138 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2139 | |
2140 | /* signals can be posted during this window */ | |
2141 | ||
3e7cd6c4 | 2142 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2143 | goto relock; |
2144 | ||
f6b76d4f | 2145 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2146 | } |
2147 | ||
7bcf6a2c | 2148 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
2149 | /* It released the siglock. */ |
2150 | goto relock; | |
2151 | } | |
2152 | ||
2153 | /* | |
2154 | * We didn't actually stop, due to a race | |
2155 | * with SIGCONT or something like that. | |
2156 | */ | |
2157 | continue; | |
2158 | } | |
2159 | ||
f6b76d4f | 2160 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2161 | |
2162 | /* | |
2163 | * Anything else is fatal, maybe with a core dump. | |
2164 | */ | |
2165 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2166 | |
1da177e4 | 2167 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2168 | if (print_fatal_signals) |
7bcf6a2c | 2169 | print_fatal_signal(regs, info->si_signo); |
1da177e4 LT |
2170 | /* |
2171 | * If it was able to dump core, this kills all | |
2172 | * other threads in the group and synchronizes with | |
2173 | * their demise. If we lost the race with another | |
2174 | * thread getting here, it set group_exit_code | |
2175 | * first and our do_group_exit call below will use | |
2176 | * that value and ignore the one we pass it. | |
2177 | */ | |
7bcf6a2c | 2178 | do_coredump(info->si_signo, info->si_signo, regs); |
1da177e4 LT |
2179 | } |
2180 | ||
2181 | /* | |
2182 | * Death signals, no core dump. | |
2183 | */ | |
7bcf6a2c | 2184 | do_group_exit(info->si_signo); |
1da177e4 LT |
2185 | /* NOTREACHED */ |
2186 | } | |
f6b76d4f | 2187 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2188 | return signr; |
2189 | } | |
2190 | ||
d12619b5 ON |
2191 | void exit_signals(struct task_struct *tsk) |
2192 | { | |
2193 | int group_stop = 0; | |
5dee1707 | 2194 | struct task_struct *t; |
d12619b5 | 2195 | |
5dee1707 ON |
2196 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2197 | tsk->flags |= PF_EXITING; | |
2198 | return; | |
d12619b5 ON |
2199 | } |
2200 | ||
5dee1707 | 2201 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2202 | /* |
2203 | * From now this task is not visible for group-wide signals, | |
2204 | * see wants_signal(), do_signal_stop(). | |
2205 | */ | |
2206 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
2207 | if (!signal_pending(tsk)) |
2208 | goto out; | |
2209 | ||
2210 | /* It could be that __group_complete_signal() choose us to | |
2211 | * notify about group-wide signal. Another thread should be | |
2212 | * woken now to take the signal since we will not. | |
2213 | */ | |
2214 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
2215 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
2216 | recalc_sigpending_and_wake(t); | |
2217 | ||
39efa3ef | 2218 | if (unlikely(tsk->group_stop & GROUP_STOP_PENDING) && |
e5c1902e | 2219 | task_participate_group_stop(tsk)) |
edf2ed15 | 2220 | group_stop = CLD_STOPPED; |
5dee1707 | 2221 | out: |
d12619b5 ON |
2222 | spin_unlock_irq(&tsk->sighand->siglock); |
2223 | ||
62bcf9d9 TH |
2224 | /* |
2225 | * If group stop has completed, deliver the notification. This | |
2226 | * should always go to the real parent of the group leader. | |
2227 | */ | |
ae6d2ed7 | 2228 | if (unlikely(group_stop)) { |
d12619b5 | 2229 | read_lock(&tasklist_lock); |
62bcf9d9 | 2230 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2231 | read_unlock(&tasklist_lock); |
2232 | } | |
2233 | } | |
2234 | ||
1da177e4 LT |
2235 | EXPORT_SYMBOL(recalc_sigpending); |
2236 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2237 | EXPORT_SYMBOL(flush_signals); | |
2238 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2239 | EXPORT_SYMBOL(send_sig); |
2240 | EXPORT_SYMBOL(send_sig_info); | |
2241 | EXPORT_SYMBOL(sigprocmask); | |
2242 | EXPORT_SYMBOL(block_all_signals); | |
2243 | EXPORT_SYMBOL(unblock_all_signals); | |
2244 | ||
2245 | ||
2246 | /* | |
2247 | * System call entry points. | |
2248 | */ | |
2249 | ||
754fe8d2 | 2250 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2251 | { |
2252 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2253 | return restart->fn(restart); | |
2254 | } | |
2255 | ||
2256 | long do_no_restart_syscall(struct restart_block *param) | |
2257 | { | |
2258 | return -EINTR; | |
2259 | } | |
2260 | ||
2261 | /* | |
2262 | * We don't need to get the kernel lock - this is all local to this | |
2263 | * particular thread.. (and that's good, because this is _heavily_ | |
2264 | * used by various programs) | |
2265 | */ | |
2266 | ||
2267 | /* | |
2268 | * This is also useful for kernel threads that want to temporarily | |
2269 | * (or permanently) block certain signals. | |
2270 | * | |
2271 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2272 | * interface happily blocks "unblockable" signals like SIGKILL | |
2273 | * and friends. | |
2274 | */ | |
2275 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2276 | { | |
2277 | int error; | |
1da177e4 LT |
2278 | |
2279 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
2280 | if (oldset) |
2281 | *oldset = current->blocked; | |
2282 | ||
1da177e4 LT |
2283 | error = 0; |
2284 | switch (how) { | |
2285 | case SIG_BLOCK: | |
2286 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2287 | break; | |
2288 | case SIG_UNBLOCK: | |
2289 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2290 | break; | |
2291 | case SIG_SETMASK: | |
2292 | current->blocked = *set; | |
2293 | break; | |
2294 | default: | |
2295 | error = -EINVAL; | |
2296 | } | |
2297 | recalc_sigpending(); | |
2298 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 2299 | |
1da177e4 LT |
2300 | return error; |
2301 | } | |
2302 | ||
17da2bd9 HC |
2303 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set, |
2304 | sigset_t __user *, oset, size_t, sigsetsize) | |
1da177e4 LT |
2305 | { |
2306 | int error = -EINVAL; | |
2307 | sigset_t old_set, new_set; | |
2308 | ||
2309 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2310 | if (sigsetsize != sizeof(sigset_t)) | |
2311 | goto out; | |
2312 | ||
2313 | if (set) { | |
2314 | error = -EFAULT; | |
2315 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2316 | goto out; | |
2317 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2318 | ||
2319 | error = sigprocmask(how, &new_set, &old_set); | |
2320 | if (error) | |
2321 | goto out; | |
2322 | if (oset) | |
2323 | goto set_old; | |
2324 | } else if (oset) { | |
2325 | spin_lock_irq(¤t->sighand->siglock); | |
2326 | old_set = current->blocked; | |
2327 | spin_unlock_irq(¤t->sighand->siglock); | |
2328 | ||
2329 | set_old: | |
2330 | error = -EFAULT; | |
2331 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2332 | goto out; | |
2333 | } | |
2334 | error = 0; | |
2335 | out: | |
2336 | return error; | |
2337 | } | |
2338 | ||
2339 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2340 | { | |
2341 | long error = -EINVAL; | |
2342 | sigset_t pending; | |
2343 | ||
2344 | if (sigsetsize > sizeof(sigset_t)) | |
2345 | goto out; | |
2346 | ||
2347 | spin_lock_irq(¤t->sighand->siglock); | |
2348 | sigorsets(&pending, ¤t->pending.signal, | |
2349 | ¤t->signal->shared_pending.signal); | |
2350 | spin_unlock_irq(¤t->sighand->siglock); | |
2351 | ||
2352 | /* Outside the lock because only this thread touches it. */ | |
2353 | sigandsets(&pending, ¤t->blocked, &pending); | |
2354 | ||
2355 | error = -EFAULT; | |
2356 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2357 | error = 0; | |
2358 | ||
2359 | out: | |
2360 | return error; | |
2361 | } | |
2362 | ||
17da2bd9 | 2363 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize) |
1da177e4 LT |
2364 | { |
2365 | return do_sigpending(set, sigsetsize); | |
2366 | } | |
2367 | ||
2368 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2369 | ||
2370 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2371 | { | |
2372 | int err; | |
2373 | ||
2374 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2375 | return -EFAULT; | |
2376 | if (from->si_code < 0) | |
2377 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2378 | ? -EFAULT : 0; | |
2379 | /* | |
2380 | * If you change siginfo_t structure, please be sure | |
2381 | * this code is fixed accordingly. | |
fba2afaa DL |
2382 | * Please remember to update the signalfd_copyinfo() function |
2383 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2384 | * It should never copy any pad contained in the structure |
2385 | * to avoid security leaks, but must copy the generic | |
2386 | * 3 ints plus the relevant union member. | |
2387 | */ | |
2388 | err = __put_user(from->si_signo, &to->si_signo); | |
2389 | err |= __put_user(from->si_errno, &to->si_errno); | |
2390 | err |= __put_user((short)from->si_code, &to->si_code); | |
2391 | switch (from->si_code & __SI_MASK) { | |
2392 | case __SI_KILL: | |
2393 | err |= __put_user(from->si_pid, &to->si_pid); | |
2394 | err |= __put_user(from->si_uid, &to->si_uid); | |
2395 | break; | |
2396 | case __SI_TIMER: | |
2397 | err |= __put_user(from->si_tid, &to->si_tid); | |
2398 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2399 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2400 | break; | |
2401 | case __SI_POLL: | |
2402 | err |= __put_user(from->si_band, &to->si_band); | |
2403 | err |= __put_user(from->si_fd, &to->si_fd); | |
2404 | break; | |
2405 | case __SI_FAULT: | |
2406 | err |= __put_user(from->si_addr, &to->si_addr); | |
2407 | #ifdef __ARCH_SI_TRAPNO | |
2408 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2409 | #endif |
2410 | #ifdef BUS_MCEERR_AO | |
2411 | /* | |
2412 | * Other callers might not initialize the si_lsb field, | |
2413 | * so check explicitely for the right codes here. | |
2414 | */ | |
2415 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2416 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2417 | #endif |
2418 | break; | |
2419 | case __SI_CHLD: | |
2420 | err |= __put_user(from->si_pid, &to->si_pid); | |
2421 | err |= __put_user(from->si_uid, &to->si_uid); | |
2422 | err |= __put_user(from->si_status, &to->si_status); | |
2423 | err |= __put_user(from->si_utime, &to->si_utime); | |
2424 | err |= __put_user(from->si_stime, &to->si_stime); | |
2425 | break; | |
2426 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2427 | case __SI_MESGQ: /* But this is */ | |
2428 | err |= __put_user(from->si_pid, &to->si_pid); | |
2429 | err |= __put_user(from->si_uid, &to->si_uid); | |
2430 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2431 | break; | |
2432 | default: /* this is just in case for now ... */ | |
2433 | err |= __put_user(from->si_pid, &to->si_pid); | |
2434 | err |= __put_user(from->si_uid, &to->si_uid); | |
2435 | break; | |
2436 | } | |
2437 | return err; | |
2438 | } | |
2439 | ||
2440 | #endif | |
2441 | ||
17da2bd9 HC |
2442 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2443 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2444 | size_t, sigsetsize) | |
1da177e4 LT |
2445 | { |
2446 | int ret, sig; | |
2447 | sigset_t these; | |
2448 | struct timespec ts; | |
2449 | siginfo_t info; | |
2450 | long timeout = 0; | |
2451 | ||
2452 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2453 | if (sigsetsize != sizeof(sigset_t)) | |
2454 | return -EINVAL; | |
2455 | ||
2456 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2457 | return -EFAULT; | |
2458 | ||
2459 | /* | |
2460 | * Invert the set of allowed signals to get those we | |
2461 | * want to block. | |
2462 | */ | |
2463 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2464 | signotset(&these); | |
2465 | ||
2466 | if (uts) { | |
2467 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2468 | return -EFAULT; | |
2469 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2470 | || ts.tv_sec < 0) | |
2471 | return -EINVAL; | |
2472 | } | |
2473 | ||
2474 | spin_lock_irq(¤t->sighand->siglock); | |
2475 | sig = dequeue_signal(current, &these, &info); | |
2476 | if (!sig) { | |
2477 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2478 | if (uts) | |
2479 | timeout = (timespec_to_jiffies(&ts) | |
2480 | + (ts.tv_sec || ts.tv_nsec)); | |
2481 | ||
2482 | if (timeout) { | |
2483 | /* None ready -- temporarily unblock those we're | |
2484 | * interested while we are sleeping in so that we'll | |
2485 | * be awakened when they arrive. */ | |
2486 | current->real_blocked = current->blocked; | |
2487 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2488 | recalc_sigpending(); | |
2489 | spin_unlock_irq(¤t->sighand->siglock); | |
2490 | ||
75bcc8c5 | 2491 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2492 | |
1da177e4 LT |
2493 | spin_lock_irq(¤t->sighand->siglock); |
2494 | sig = dequeue_signal(current, &these, &info); | |
2495 | current->blocked = current->real_blocked; | |
2496 | siginitset(¤t->real_blocked, 0); | |
2497 | recalc_sigpending(); | |
2498 | } | |
2499 | } | |
2500 | spin_unlock_irq(¤t->sighand->siglock); | |
2501 | ||
2502 | if (sig) { | |
2503 | ret = sig; | |
2504 | if (uinfo) { | |
2505 | if (copy_siginfo_to_user(uinfo, &info)) | |
2506 | ret = -EFAULT; | |
2507 | } | |
2508 | } else { | |
2509 | ret = -EAGAIN; | |
2510 | if (timeout) | |
2511 | ret = -EINTR; | |
2512 | } | |
2513 | ||
2514 | return ret; | |
2515 | } | |
2516 | ||
17da2bd9 | 2517 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2518 | { |
2519 | struct siginfo info; | |
2520 | ||
2521 | info.si_signo = sig; | |
2522 | info.si_errno = 0; | |
2523 | info.si_code = SI_USER; | |
b488893a | 2524 | info.si_pid = task_tgid_vnr(current); |
76aac0e9 | 2525 | info.si_uid = current_uid(); |
1da177e4 LT |
2526 | |
2527 | return kill_something_info(sig, &info, pid); | |
2528 | } | |
2529 | ||
30b4ae8a TG |
2530 | static int |
2531 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2532 | { |
1da177e4 | 2533 | struct task_struct *p; |
30b4ae8a | 2534 | int error = -ESRCH; |
1da177e4 | 2535 | |
3547ff3a | 2536 | rcu_read_lock(); |
228ebcbe | 2537 | p = find_task_by_vpid(pid); |
b488893a | 2538 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2539 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2540 | /* |
2541 | * The null signal is a permissions and process existence | |
2542 | * probe. No signal is actually delivered. | |
2543 | */ | |
4a30debf ON |
2544 | if (!error && sig) { |
2545 | error = do_send_sig_info(sig, info, p, false); | |
2546 | /* | |
2547 | * If lock_task_sighand() failed we pretend the task | |
2548 | * dies after receiving the signal. The window is tiny, | |
2549 | * and the signal is private anyway. | |
2550 | */ | |
2551 | if (unlikely(error == -ESRCH)) | |
2552 | error = 0; | |
1da177e4 LT |
2553 | } |
2554 | } | |
3547ff3a | 2555 | rcu_read_unlock(); |
6dd69f10 | 2556 | |
1da177e4 LT |
2557 | return error; |
2558 | } | |
2559 | ||
30b4ae8a TG |
2560 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2561 | { | |
2562 | struct siginfo info; | |
2563 | ||
2564 | info.si_signo = sig; | |
2565 | info.si_errno = 0; | |
2566 | info.si_code = SI_TKILL; | |
2567 | info.si_pid = task_tgid_vnr(current); | |
2568 | info.si_uid = current_uid(); | |
2569 | ||
2570 | return do_send_specific(tgid, pid, sig, &info); | |
2571 | } | |
2572 | ||
6dd69f10 VL |
2573 | /** |
2574 | * sys_tgkill - send signal to one specific thread | |
2575 | * @tgid: the thread group ID of the thread | |
2576 | * @pid: the PID of the thread | |
2577 | * @sig: signal to be sent | |
2578 | * | |
72fd4a35 | 2579 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2580 | * exists but it's not belonging to the target process anymore. This |
2581 | * method solves the problem of threads exiting and PIDs getting reused. | |
2582 | */ | |
a5f8fa9e | 2583 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2584 | { |
2585 | /* This is only valid for single tasks */ | |
2586 | if (pid <= 0 || tgid <= 0) | |
2587 | return -EINVAL; | |
2588 | ||
2589 | return do_tkill(tgid, pid, sig); | |
2590 | } | |
2591 | ||
1da177e4 LT |
2592 | /* |
2593 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2594 | */ | |
a5f8fa9e | 2595 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2596 | { |
1da177e4 LT |
2597 | /* This is only valid for single tasks */ |
2598 | if (pid <= 0) | |
2599 | return -EINVAL; | |
2600 | ||
6dd69f10 | 2601 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2602 | } |
2603 | ||
a5f8fa9e HC |
2604 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2605 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2606 | { |
2607 | siginfo_t info; | |
2608 | ||
2609 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2610 | return -EFAULT; | |
2611 | ||
2612 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2613 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2614 | */ | |
2615 | if (info.si_code != SI_QUEUE) { | |
2616 | /* We used to allow any < 0 si_code */ | |
2617 | WARN_ON_ONCE(info.si_code < 0); | |
1da177e4 | 2618 | return -EPERM; |
da48524e | 2619 | } |
1da177e4 LT |
2620 | info.si_signo = sig; |
2621 | ||
2622 | /* POSIX.1b doesn't mention process groups. */ | |
2623 | return kill_proc_info(sig, &info, pid); | |
2624 | } | |
2625 | ||
62ab4505 TG |
2626 | long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
2627 | { | |
2628 | /* This is only valid for single tasks */ | |
2629 | if (pid <= 0 || tgid <= 0) | |
2630 | return -EINVAL; | |
2631 | ||
2632 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2633 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2634 | */ | |
2635 | if (info->si_code != SI_QUEUE) { | |
2636 | /* We used to allow any < 0 si_code */ | |
2637 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 2638 | return -EPERM; |
da48524e | 2639 | } |
62ab4505 TG |
2640 | info->si_signo = sig; |
2641 | ||
2642 | return do_send_specific(tgid, pid, sig, info); | |
2643 | } | |
2644 | ||
2645 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
2646 | siginfo_t __user *, uinfo) | |
2647 | { | |
2648 | siginfo_t info; | |
2649 | ||
2650 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2651 | return -EFAULT; | |
2652 | ||
2653 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
2654 | } | |
2655 | ||
88531f72 | 2656 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 2657 | { |
93585eea | 2658 | struct task_struct *t = current; |
1da177e4 | 2659 | struct k_sigaction *k; |
71fabd5e | 2660 | sigset_t mask; |
1da177e4 | 2661 | |
7ed20e1a | 2662 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2663 | return -EINVAL; |
2664 | ||
93585eea | 2665 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
2666 | |
2667 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2668 | if (oact) |
2669 | *oact = *k; | |
2670 | ||
2671 | if (act) { | |
9ac95f2f ON |
2672 | sigdelsetmask(&act->sa.sa_mask, |
2673 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2674 | *k = *act; |
1da177e4 LT |
2675 | /* |
2676 | * POSIX 3.3.1.3: | |
2677 | * "Setting a signal action to SIG_IGN for a signal that is | |
2678 | * pending shall cause the pending signal to be discarded, | |
2679 | * whether or not it is blocked." | |
2680 | * | |
2681 | * "Setting a signal action to SIG_DFL for a signal that is | |
2682 | * pending and whose default action is to ignore the signal | |
2683 | * (for example, SIGCHLD), shall cause the pending signal to | |
2684 | * be discarded, whether or not it is blocked" | |
2685 | */ | |
35de254d | 2686 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
2687 | sigemptyset(&mask); |
2688 | sigaddset(&mask, sig); | |
2689 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2690 | do { |
71fabd5e | 2691 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2692 | t = next_thread(t); |
2693 | } while (t != current); | |
1da177e4 | 2694 | } |
1da177e4 LT |
2695 | } |
2696 | ||
2697 | spin_unlock_irq(¤t->sighand->siglock); | |
2698 | return 0; | |
2699 | } | |
2700 | ||
2701 | int | |
2702 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2703 | { | |
2704 | stack_t oss; | |
2705 | int error; | |
2706 | ||
0083fc2c LT |
2707 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
2708 | oss.ss_size = current->sas_ss_size; | |
2709 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
2710 | |
2711 | if (uss) { | |
2712 | void __user *ss_sp; | |
2713 | size_t ss_size; | |
2714 | int ss_flags; | |
2715 | ||
2716 | error = -EFAULT; | |
0dd8486b LT |
2717 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
2718 | goto out; | |
2719 | error = __get_user(ss_sp, &uss->ss_sp) | | |
2720 | __get_user(ss_flags, &uss->ss_flags) | | |
2721 | __get_user(ss_size, &uss->ss_size); | |
2722 | if (error) | |
1da177e4 LT |
2723 | goto out; |
2724 | ||
2725 | error = -EPERM; | |
2726 | if (on_sig_stack(sp)) | |
2727 | goto out; | |
2728 | ||
2729 | error = -EINVAL; | |
2730 | /* | |
2731 | * | |
2732 | * Note - this code used to test ss_flags incorrectly | |
2733 | * old code may have been written using ss_flags==0 | |
2734 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2735 | * way that worked) - this fix preserves that older | |
2736 | * mechanism | |
2737 | */ | |
2738 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2739 | goto out; | |
2740 | ||
2741 | if (ss_flags == SS_DISABLE) { | |
2742 | ss_size = 0; | |
2743 | ss_sp = NULL; | |
2744 | } else { | |
2745 | error = -ENOMEM; | |
2746 | if (ss_size < MINSIGSTKSZ) | |
2747 | goto out; | |
2748 | } | |
2749 | ||
2750 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2751 | current->sas_ss_size = ss_size; | |
2752 | } | |
2753 | ||
0083fc2c | 2754 | error = 0; |
1da177e4 LT |
2755 | if (uoss) { |
2756 | error = -EFAULT; | |
0083fc2c | 2757 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 2758 | goto out; |
0083fc2c LT |
2759 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
2760 | __put_user(oss.ss_size, &uoss->ss_size) | | |
2761 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
2762 | } |
2763 | ||
1da177e4 LT |
2764 | out: |
2765 | return error; | |
2766 | } | |
2767 | ||
2768 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2769 | ||
b290ebe2 | 2770 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 LT |
2771 | { |
2772 | return do_sigpending(set, sizeof(*set)); | |
2773 | } | |
2774 | ||
2775 | #endif | |
2776 | ||
2777 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2778 | /* Some platforms have their own version with special arguments others | |
2779 | support only sys_rt_sigprocmask. */ | |
2780 | ||
b290ebe2 HC |
2781 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set, |
2782 | old_sigset_t __user *, oset) | |
1da177e4 LT |
2783 | { |
2784 | int error; | |
2785 | old_sigset_t old_set, new_set; | |
2786 | ||
2787 | if (set) { | |
2788 | error = -EFAULT; | |
2789 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2790 | goto out; | |
2791 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2792 | ||
2793 | spin_lock_irq(¤t->sighand->siglock); | |
2794 | old_set = current->blocked.sig[0]; | |
2795 | ||
2796 | error = 0; | |
2797 | switch (how) { | |
2798 | default: | |
2799 | error = -EINVAL; | |
2800 | break; | |
2801 | case SIG_BLOCK: | |
2802 | sigaddsetmask(¤t->blocked, new_set); | |
2803 | break; | |
2804 | case SIG_UNBLOCK: | |
2805 | sigdelsetmask(¤t->blocked, new_set); | |
2806 | break; | |
2807 | case SIG_SETMASK: | |
2808 | current->blocked.sig[0] = new_set; | |
2809 | break; | |
2810 | } | |
2811 | ||
2812 | recalc_sigpending(); | |
2813 | spin_unlock_irq(¤t->sighand->siglock); | |
2814 | if (error) | |
2815 | goto out; | |
2816 | if (oset) | |
2817 | goto set_old; | |
2818 | } else if (oset) { | |
2819 | old_set = current->blocked.sig[0]; | |
2820 | set_old: | |
2821 | error = -EFAULT; | |
2822 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2823 | goto out; | |
2824 | } | |
2825 | error = 0; | |
2826 | out: | |
2827 | return error; | |
2828 | } | |
2829 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2830 | ||
2831 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
d4e82042 HC |
2832 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
2833 | const struct sigaction __user *, act, | |
2834 | struct sigaction __user *, oact, | |
2835 | size_t, sigsetsize) | |
1da177e4 LT |
2836 | { |
2837 | struct k_sigaction new_sa, old_sa; | |
2838 | int ret = -EINVAL; | |
2839 | ||
2840 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2841 | if (sigsetsize != sizeof(sigset_t)) | |
2842 | goto out; | |
2843 | ||
2844 | if (act) { | |
2845 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2846 | return -EFAULT; | |
2847 | } | |
2848 | ||
2849 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2850 | ||
2851 | if (!ret && oact) { | |
2852 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2853 | return -EFAULT; | |
2854 | } | |
2855 | out: | |
2856 | return ret; | |
2857 | } | |
2858 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2859 | ||
2860 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2861 | ||
2862 | /* | |
2863 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2864 | */ | |
a5f8fa9e | 2865 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
2866 | { |
2867 | /* SMP safe */ | |
2868 | return current->blocked.sig[0]; | |
2869 | } | |
2870 | ||
a5f8fa9e | 2871 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 LT |
2872 | { |
2873 | int old; | |
2874 | ||
2875 | spin_lock_irq(¤t->sighand->siglock); | |
2876 | old = current->blocked.sig[0]; | |
2877 | ||
2878 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2879 | sigmask(SIGSTOP))); | |
2880 | recalc_sigpending(); | |
2881 | spin_unlock_irq(¤t->sighand->siglock); | |
2882 | ||
2883 | return old; | |
2884 | } | |
2885 | #endif /* __ARCH_WANT_SGETMASK */ | |
2886 | ||
2887 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2888 | /* | |
2889 | * For backwards compatibility. Functionality superseded by sigaction. | |
2890 | */ | |
a5f8fa9e | 2891 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
2892 | { |
2893 | struct k_sigaction new_sa, old_sa; | |
2894 | int ret; | |
2895 | ||
2896 | new_sa.sa.sa_handler = handler; | |
2897 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2898 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2899 | |
2900 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2901 | ||
2902 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2903 | } | |
2904 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2905 | ||
2906 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2907 | ||
a5f8fa9e | 2908 | SYSCALL_DEFINE0(pause) |
1da177e4 LT |
2909 | { |
2910 | current->state = TASK_INTERRUPTIBLE; | |
2911 | schedule(); | |
2912 | return -ERESTARTNOHAND; | |
2913 | } | |
2914 | ||
2915 | #endif | |
2916 | ||
150256d8 | 2917 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
d4e82042 | 2918 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
2919 | { |
2920 | sigset_t newset; | |
2921 | ||
2922 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2923 | if (sigsetsize != sizeof(sigset_t)) | |
2924 | return -EINVAL; | |
2925 | ||
2926 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2927 | return -EFAULT; | |
2928 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2929 | ||
2930 | spin_lock_irq(¤t->sighand->siglock); | |
2931 | current->saved_sigmask = current->blocked; | |
2932 | current->blocked = newset; | |
2933 | recalc_sigpending(); | |
2934 | spin_unlock_irq(¤t->sighand->siglock); | |
2935 | ||
2936 | current->state = TASK_INTERRUPTIBLE; | |
2937 | schedule(); | |
4e4c22c7 | 2938 | set_restore_sigmask(); |
150256d8 DW |
2939 | return -ERESTARTNOHAND; |
2940 | } | |
2941 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2942 | ||
f269fdd1 DH |
2943 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2944 | { | |
2945 | return NULL; | |
2946 | } | |
2947 | ||
1da177e4 LT |
2948 | void __init signals_init(void) |
2949 | { | |
0a31bd5f | 2950 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2951 | } |
67fc4e0c JW |
2952 | |
2953 | #ifdef CONFIG_KGDB_KDB | |
2954 | #include <linux/kdb.h> | |
2955 | /* | |
2956 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
2957 | * signal internals. This function checks if the required locks are | |
2958 | * available before calling the main signal code, to avoid kdb | |
2959 | * deadlocks. | |
2960 | */ | |
2961 | void | |
2962 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
2963 | { | |
2964 | static struct task_struct *kdb_prev_t; | |
2965 | int sig, new_t; | |
2966 | if (!spin_trylock(&t->sighand->siglock)) { | |
2967 | kdb_printf("Can't do kill command now.\n" | |
2968 | "The sigmask lock is held somewhere else in " | |
2969 | "kernel, try again later\n"); | |
2970 | return; | |
2971 | } | |
2972 | spin_unlock(&t->sighand->siglock); | |
2973 | new_t = kdb_prev_t != t; | |
2974 | kdb_prev_t = t; | |
2975 | if (t->state != TASK_RUNNING && new_t) { | |
2976 | kdb_printf("Process is not RUNNING, sending a signal from " | |
2977 | "kdb risks deadlock\n" | |
2978 | "on the run queue locks. " | |
2979 | "The signal has _not_ been sent.\n" | |
2980 | "Reissue the kill command if you want to risk " | |
2981 | "the deadlock.\n"); | |
2982 | return; | |
2983 | } | |
2984 | sig = info->si_signo; | |
2985 | if (send_sig_info(sig, info, t)) | |
2986 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
2987 | sig, t->pid); | |
2988 | else | |
2989 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
2990 | } | |
2991 | #endif /* CONFIG_KGDB_KDB */ |