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 | ||
13 | #include <linux/config.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/smp_lock.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/sched.h> | |
19 | #include <linux/fs.h> | |
20 | #include <linux/tty.h> | |
21 | #include <linux/binfmts.h> | |
22 | #include <linux/security.h> | |
23 | #include <linux/syscalls.h> | |
24 | #include <linux/ptrace.h> | |
7ed20e1a | 25 | #include <linux/signal.h> |
c2f0c7c3 | 26 | #include <linux/audit.h> |
c59ede7b | 27 | #include <linux/capability.h> |
1da177e4 LT |
28 | #include <asm/param.h> |
29 | #include <asm/uaccess.h> | |
30 | #include <asm/unistd.h> | |
31 | #include <asm/siginfo.h> | |
32 | ||
33 | /* | |
34 | * SLAB caches for signal bits. | |
35 | */ | |
36 | ||
37 | static kmem_cache_t *sigqueue_cachep; | |
38 | ||
39 | /* | |
40 | * In POSIX a signal is sent either to a specific thread (Linux task) | |
41 | * or to the process as a whole (Linux thread group). How the signal | |
42 | * is sent determines whether it's to one thread or the whole group, | |
43 | * which determines which signal mask(s) are involved in blocking it | |
44 | * from being delivered until later. When the signal is delivered, | |
45 | * either it's caught or ignored by a user handler or it has a default | |
46 | * effect that applies to the whole thread group (POSIX process). | |
47 | * | |
48 | * The possible effects an unblocked signal set to SIG_DFL can have are: | |
49 | * ignore - Nothing Happens | |
50 | * terminate - kill the process, i.e. all threads in the group, | |
51 | * similar to exit_group. The group leader (only) reports | |
52 | * WIFSIGNALED status to its parent. | |
53 | * coredump - write a core dump file describing all threads using | |
54 | * the same mm and then kill all those threads | |
55 | * stop - stop all the threads in the group, i.e. TASK_STOPPED state | |
56 | * | |
57 | * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored. | |
58 | * Other signals when not blocked and set to SIG_DFL behaves as follows. | |
59 | * The job control signals also have other special effects. | |
60 | * | |
61 | * +--------------------+------------------+ | |
62 | * | POSIX signal | default action | | |
63 | * +--------------------+------------------+ | |
64 | * | SIGHUP | terminate | | |
65 | * | SIGINT | terminate | | |
66 | * | SIGQUIT | coredump | | |
67 | * | SIGILL | coredump | | |
68 | * | SIGTRAP | coredump | | |
69 | * | SIGABRT/SIGIOT | coredump | | |
70 | * | SIGBUS | coredump | | |
71 | * | SIGFPE | coredump | | |
72 | * | SIGKILL | terminate(+) | | |
73 | * | SIGUSR1 | terminate | | |
74 | * | SIGSEGV | coredump | | |
75 | * | SIGUSR2 | terminate | | |
76 | * | SIGPIPE | terminate | | |
77 | * | SIGALRM | terminate | | |
78 | * | SIGTERM | terminate | | |
79 | * | SIGCHLD | ignore | | |
80 | * | SIGCONT | ignore(*) | | |
81 | * | SIGSTOP | stop(*)(+) | | |
82 | * | SIGTSTP | stop(*) | | |
83 | * | SIGTTIN | stop(*) | | |
84 | * | SIGTTOU | stop(*) | | |
85 | * | SIGURG | ignore | | |
86 | * | SIGXCPU | coredump | | |
87 | * | SIGXFSZ | coredump | | |
88 | * | SIGVTALRM | terminate | | |
89 | * | SIGPROF | terminate | | |
90 | * | SIGPOLL/SIGIO | terminate | | |
91 | * | SIGSYS/SIGUNUSED | coredump | | |
92 | * | SIGSTKFLT | terminate | | |
93 | * | SIGWINCH | ignore | | |
94 | * | SIGPWR | terminate | | |
95 | * | SIGRTMIN-SIGRTMAX | terminate | | |
96 | * +--------------------+------------------+ | |
97 | * | non-POSIX signal | default action | | |
98 | * +--------------------+------------------+ | |
99 | * | SIGEMT | coredump | | |
100 | * +--------------------+------------------+ | |
101 | * | |
102 | * (+) For SIGKILL and SIGSTOP the action is "always", not just "default". | |
103 | * (*) Special job control effects: | |
104 | * When SIGCONT is sent, it resumes the process (all threads in the group) | |
105 | * from TASK_STOPPED state and also clears any pending/queued stop signals | |
106 | * (any of those marked with "stop(*)"). This happens regardless of blocking, | |
107 | * catching, or ignoring SIGCONT. When any stop signal is sent, it clears | |
108 | * any pending/queued SIGCONT signals; this happens regardless of blocking, | |
109 | * catching, or ignored the stop signal, though (except for SIGSTOP) the | |
110 | * default action of stopping the process may happen later or never. | |
111 | */ | |
112 | ||
113 | #ifdef SIGEMT | |
114 | #define M_SIGEMT M(SIGEMT) | |
115 | #else | |
116 | #define M_SIGEMT 0 | |
117 | #endif | |
118 | ||
119 | #if SIGRTMIN > BITS_PER_LONG | |
120 | #define M(sig) (1ULL << ((sig)-1)) | |
121 | #else | |
122 | #define M(sig) (1UL << ((sig)-1)) | |
123 | #endif | |
124 | #define T(sig, mask) (M(sig) & (mask)) | |
125 | ||
126 | #define SIG_KERNEL_ONLY_MASK (\ | |
127 | M(SIGKILL) | M(SIGSTOP) ) | |
128 | ||
129 | #define SIG_KERNEL_STOP_MASK (\ | |
130 | M(SIGSTOP) | M(SIGTSTP) | M(SIGTTIN) | M(SIGTTOU) ) | |
131 | ||
132 | #define SIG_KERNEL_COREDUMP_MASK (\ | |
133 | M(SIGQUIT) | M(SIGILL) | M(SIGTRAP) | M(SIGABRT) | \ | |
134 | M(SIGFPE) | M(SIGSEGV) | M(SIGBUS) | M(SIGSYS) | \ | |
135 | M(SIGXCPU) | M(SIGXFSZ) | M_SIGEMT ) | |
136 | ||
137 | #define SIG_KERNEL_IGNORE_MASK (\ | |
138 | M(SIGCONT) | M(SIGCHLD) | M(SIGWINCH) | M(SIGURG) ) | |
139 | ||
140 | #define sig_kernel_only(sig) \ | |
141 | (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_ONLY_MASK)) | |
142 | #define sig_kernel_coredump(sig) \ | |
143 | (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_COREDUMP_MASK)) | |
144 | #define sig_kernel_ignore(sig) \ | |
145 | (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_IGNORE_MASK)) | |
146 | #define sig_kernel_stop(sig) \ | |
147 | (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_STOP_MASK)) | |
148 | ||
6108ccd3 | 149 | #define sig_needs_tasklist(sig) ((sig) == SIGCONT) |
a9e88e84 | 150 | |
1da177e4 LT |
151 | #define sig_user_defined(t, signr) \ |
152 | (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) && \ | |
153 | ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN)) | |
154 | ||
155 | #define sig_fatal(t, signr) \ | |
156 | (!T(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \ | |
157 | (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL) | |
158 | ||
159 | static int sig_ignored(struct task_struct *t, int sig) | |
160 | { | |
161 | void __user * handler; | |
162 | ||
163 | /* | |
164 | * Tracers always want to know about signals.. | |
165 | */ | |
166 | if (t->ptrace & PT_PTRACED) | |
167 | return 0; | |
168 | ||
169 | /* | |
170 | * Blocked signals are never ignored, since the | |
171 | * signal handler may change by the time it is | |
172 | * unblocked. | |
173 | */ | |
174 | if (sigismember(&t->blocked, sig)) | |
175 | return 0; | |
176 | ||
177 | /* Is it explicitly or implicitly ignored? */ | |
178 | handler = t->sighand->action[sig-1].sa.sa_handler; | |
179 | return handler == SIG_IGN || | |
180 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
181 | } | |
182 | ||
183 | /* | |
184 | * Re-calculate pending state from the set of locally pending | |
185 | * signals, globally pending signals, and blocked signals. | |
186 | */ | |
187 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
188 | { | |
189 | unsigned long ready; | |
190 | long i; | |
191 | ||
192 | switch (_NSIG_WORDS) { | |
193 | default: | |
194 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
195 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
196 | break; | |
197 | ||
198 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
199 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
200 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
201 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
202 | break; | |
203 | ||
204 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
205 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
206 | break; | |
207 | ||
208 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
209 | } | |
210 | return ready != 0; | |
211 | } | |
212 | ||
213 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
214 | ||
215 | fastcall void recalc_sigpending_tsk(struct task_struct *t) | |
216 | { | |
217 | if (t->signal->group_stop_count > 0 || | |
3e1d1d28 | 218 | (freezing(t)) || |
1da177e4 LT |
219 | PENDING(&t->pending, &t->blocked) || |
220 | PENDING(&t->signal->shared_pending, &t->blocked)) | |
221 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
222 | else | |
223 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
224 | } | |
225 | ||
226 | void recalc_sigpending(void) | |
227 | { | |
228 | recalc_sigpending_tsk(current); | |
229 | } | |
230 | ||
231 | /* Given the mask, find the first available signal that should be serviced. */ | |
232 | ||
233 | static int | |
234 | next_signal(struct sigpending *pending, sigset_t *mask) | |
235 | { | |
236 | unsigned long i, *s, *m, x; | |
237 | int sig = 0; | |
238 | ||
239 | s = pending->signal.sig; | |
240 | m = mask->sig; | |
241 | switch (_NSIG_WORDS) { | |
242 | default: | |
243 | for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m) | |
244 | if ((x = *s &~ *m) != 0) { | |
245 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
246 | break; | |
247 | } | |
248 | break; | |
249 | ||
250 | case 2: if ((x = s[0] &~ m[0]) != 0) | |
251 | sig = 1; | |
252 | else if ((x = s[1] &~ m[1]) != 0) | |
253 | sig = _NSIG_BPW + 1; | |
254 | else | |
255 | break; | |
256 | sig += ffz(~x); | |
257 | break; | |
258 | ||
259 | case 1: if ((x = *s &~ *m) != 0) | |
260 | sig = ffz(~x) + 1; | |
261 | break; | |
262 | } | |
263 | ||
264 | return sig; | |
265 | } | |
266 | ||
dd0fc66f | 267 | static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, |
1da177e4 LT |
268 | int override_rlimit) |
269 | { | |
270 | struct sigqueue *q = NULL; | |
271 | ||
272 | atomic_inc(&t->user->sigpending); | |
273 | if (override_rlimit || | |
274 | atomic_read(&t->user->sigpending) <= | |
275 | t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) | |
276 | q = kmem_cache_alloc(sigqueue_cachep, flags); | |
277 | if (unlikely(q == NULL)) { | |
278 | atomic_dec(&t->user->sigpending); | |
279 | } else { | |
280 | INIT_LIST_HEAD(&q->list); | |
281 | q->flags = 0; | |
1da177e4 LT |
282 | q->user = get_uid(t->user); |
283 | } | |
284 | return(q); | |
285 | } | |
286 | ||
514a01b8 | 287 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
288 | { |
289 | if (q->flags & SIGQUEUE_PREALLOC) | |
290 | return; | |
291 | atomic_dec(&q->user->sigpending); | |
292 | free_uid(q->user); | |
293 | kmem_cache_free(sigqueue_cachep, q); | |
294 | } | |
295 | ||
6a14c5c9 | 296 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
297 | { |
298 | struct sigqueue *q; | |
299 | ||
300 | sigemptyset(&queue->signal); | |
301 | while (!list_empty(&queue->list)) { | |
302 | q = list_entry(queue->list.next, struct sigqueue , list); | |
303 | list_del_init(&q->list); | |
304 | __sigqueue_free(q); | |
305 | } | |
306 | } | |
307 | ||
308 | /* | |
309 | * Flush all pending signals for a task. | |
310 | */ | |
c81addc9 | 311 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
312 | { |
313 | unsigned long flags; | |
314 | ||
315 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
316 | clear_tsk_thread_flag(t,TIF_SIGPENDING); | |
317 | flush_sigqueue(&t->pending); | |
318 | flush_sigqueue(&t->signal->shared_pending); | |
319 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
320 | } | |
321 | ||
1da177e4 LT |
322 | /* |
323 | * Flush all handlers for a task. | |
324 | */ | |
325 | ||
326 | void | |
327 | flush_signal_handlers(struct task_struct *t, int force_default) | |
328 | { | |
329 | int i; | |
330 | struct k_sigaction *ka = &t->sighand->action[0]; | |
331 | for (i = _NSIG ; i != 0 ; i--) { | |
332 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
333 | ka->sa.sa_handler = SIG_DFL; | |
334 | ka->sa.sa_flags = 0; | |
335 | sigemptyset(&ka->sa.sa_mask); | |
336 | ka++; | |
337 | } | |
338 | } | |
339 | ||
340 | ||
341 | /* Notify the system that a driver wants to block all signals for this | |
342 | * process, and wants to be notified if any signals at all were to be | |
343 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
344 | * signal will be acted upon after all. If the notifier routine returns 0, | |
345 | * then then signal will be blocked. Only one block per process is | |
346 | * allowed. priv is a pointer to private data that the notifier routine | |
347 | * can use to determine if the signal should be blocked or not. */ | |
348 | ||
349 | void | |
350 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
351 | { | |
352 | unsigned long flags; | |
353 | ||
354 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
355 | current->notifier_mask = mask; | |
356 | current->notifier_data = priv; | |
357 | current->notifier = notifier; | |
358 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
359 | } | |
360 | ||
361 | /* Notify the system that blocking has ended. */ | |
362 | ||
363 | void | |
364 | unblock_all_signals(void) | |
365 | { | |
366 | unsigned long flags; | |
367 | ||
368 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
369 | current->notifier = NULL; | |
370 | current->notifier_data = NULL; | |
371 | recalc_sigpending(); | |
372 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
373 | } | |
374 | ||
858119e1 | 375 | static int collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
376 | { |
377 | struct sigqueue *q, *first = NULL; | |
378 | int still_pending = 0; | |
379 | ||
380 | if (unlikely(!sigismember(&list->signal, sig))) | |
381 | return 0; | |
382 | ||
383 | /* | |
384 | * Collect the siginfo appropriate to this signal. Check if | |
385 | * there is another siginfo for the same signal. | |
386 | */ | |
387 | list_for_each_entry(q, &list->list, list) { | |
388 | if (q->info.si_signo == sig) { | |
389 | if (first) { | |
390 | still_pending = 1; | |
391 | break; | |
392 | } | |
393 | first = q; | |
394 | } | |
395 | } | |
396 | if (first) { | |
397 | list_del_init(&first->list); | |
398 | copy_siginfo(info, &first->info); | |
399 | __sigqueue_free(first); | |
400 | if (!still_pending) | |
401 | sigdelset(&list->signal, sig); | |
402 | } else { | |
403 | ||
404 | /* Ok, it wasn't in the queue. This must be | |
405 | a fast-pathed signal or we must have been | |
406 | out of queue space. So zero out the info. | |
407 | */ | |
408 | sigdelset(&list->signal, sig); | |
409 | info->si_signo = sig; | |
410 | info->si_errno = 0; | |
411 | info->si_code = 0; | |
412 | info->si_pid = 0; | |
413 | info->si_uid = 0; | |
414 | } | |
415 | return 1; | |
416 | } | |
417 | ||
418 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
419 | siginfo_t *info) | |
420 | { | |
421 | int sig = 0; | |
422 | ||
b17b0421 | 423 | sig = next_signal(pending, mask); |
1da177e4 LT |
424 | if (sig) { |
425 | if (current->notifier) { | |
426 | if (sigismember(current->notifier_mask, sig)) { | |
427 | if (!(current->notifier)(current->notifier_data)) { | |
428 | clear_thread_flag(TIF_SIGPENDING); | |
429 | return 0; | |
430 | } | |
431 | } | |
432 | } | |
433 | ||
434 | if (!collect_signal(sig, pending, info)) | |
435 | sig = 0; | |
436 | ||
437 | } | |
438 | recalc_sigpending(); | |
439 | ||
440 | return sig; | |
441 | } | |
442 | ||
443 | /* | |
444 | * Dequeue a signal and return the element to the caller, which is | |
445 | * expected to free it. | |
446 | * | |
447 | * All callers have to hold the siglock. | |
448 | */ | |
449 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
450 | { | |
451 | int signr = __dequeue_signal(&tsk->pending, mask, info); | |
452 | if (!signr) | |
453 | signr = __dequeue_signal(&tsk->signal->shared_pending, | |
454 | mask, info); | |
455 | if (signr && unlikely(sig_kernel_stop(signr))) { | |
456 | /* | |
457 | * Set a marker that we have dequeued a stop signal. Our | |
458 | * caller might release the siglock and then the pending | |
459 | * stop signal it is about to process is no longer in the | |
460 | * pending bitmasks, but must still be cleared by a SIGCONT | |
461 | * (and overruled by a SIGKILL). So those cases clear this | |
462 | * shared flag after we've set it. Note that this flag may | |
463 | * remain set after the signal we return is ignored or | |
464 | * handled. That doesn't matter because its only purpose | |
465 | * is to alert stop-signal processing code when another | |
466 | * processor has come along and cleared the flag. | |
467 | */ | |
788e05a6 ON |
468 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) |
469 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; | |
1da177e4 LT |
470 | } |
471 | if ( signr && | |
472 | ((info->si_code & __SI_MASK) == __SI_TIMER) && | |
473 | info->si_sys_private){ | |
474 | /* | |
475 | * Release the siglock to ensure proper locking order | |
476 | * of timer locks outside of siglocks. Note, we leave | |
477 | * irqs disabled here, since the posix-timers code is | |
478 | * about to disable them again anyway. | |
479 | */ | |
480 | spin_unlock(&tsk->sighand->siglock); | |
481 | do_schedule_next_timer(info); | |
482 | spin_lock(&tsk->sighand->siglock); | |
483 | } | |
484 | return signr; | |
485 | } | |
486 | ||
487 | /* | |
488 | * Tell a process that it has a new active signal.. | |
489 | * | |
490 | * NOTE! we rely on the previous spin_lock to | |
491 | * lock interrupts for us! We can only be called with | |
492 | * "siglock" held, and the local interrupt must | |
493 | * have been disabled when that got acquired! | |
494 | * | |
495 | * No need to set need_resched since signal event passing | |
496 | * goes through ->blocked | |
497 | */ | |
498 | void signal_wake_up(struct task_struct *t, int resume) | |
499 | { | |
500 | unsigned int mask; | |
501 | ||
502 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
503 | ||
504 | /* | |
505 | * For SIGKILL, we want to wake it up in the stopped/traced case. | |
506 | * We don't check t->state here because there is a race with it | |
507 | * executing another processor and just now entering stopped state. | |
508 | * By using wake_up_state, we ensure the process will wake up and | |
509 | * handle its death signal. | |
510 | */ | |
511 | mask = TASK_INTERRUPTIBLE; | |
512 | if (resume) | |
513 | mask |= TASK_STOPPED | TASK_TRACED; | |
514 | if (!wake_up_state(t, mask)) | |
515 | kick_process(t); | |
516 | } | |
517 | ||
71fabd5e GA |
518 | /* |
519 | * Remove signals in mask from the pending set and queue. | |
520 | * Returns 1 if any signals were found. | |
521 | * | |
522 | * All callers must be holding the siglock. | |
523 | * | |
524 | * This version takes a sigset mask and looks at all signals, | |
525 | * not just those in the first mask word. | |
526 | */ | |
527 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
528 | { | |
529 | struct sigqueue *q, *n; | |
530 | sigset_t m; | |
531 | ||
532 | sigandsets(&m, mask, &s->signal); | |
533 | if (sigisemptyset(&m)) | |
534 | return 0; | |
535 | ||
536 | signandsets(&s->signal, &s->signal, mask); | |
537 | list_for_each_entry_safe(q, n, &s->list, list) { | |
538 | if (sigismember(mask, q->info.si_signo)) { | |
539 | list_del_init(&q->list); | |
540 | __sigqueue_free(q); | |
541 | } | |
542 | } | |
543 | return 1; | |
544 | } | |
1da177e4 LT |
545 | /* |
546 | * Remove signals in mask from the pending set and queue. | |
547 | * Returns 1 if any signals were found. | |
548 | * | |
549 | * All callers must be holding the siglock. | |
550 | */ | |
551 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
552 | { | |
553 | struct sigqueue *q, *n; | |
554 | ||
555 | if (!sigtestsetmask(&s->signal, mask)) | |
556 | return 0; | |
557 | ||
558 | sigdelsetmask(&s->signal, mask); | |
559 | list_for_each_entry_safe(q, n, &s->list, list) { | |
560 | if (q->info.si_signo < SIGRTMIN && | |
561 | (mask & sigmask(q->info.si_signo))) { | |
562 | list_del_init(&q->list); | |
563 | __sigqueue_free(q); | |
564 | } | |
565 | } | |
566 | return 1; | |
567 | } | |
568 | ||
569 | /* | |
570 | * Bad permissions for sending the signal | |
571 | */ | |
572 | static int check_kill_permission(int sig, struct siginfo *info, | |
573 | struct task_struct *t) | |
574 | { | |
575 | int error = -EINVAL; | |
7ed20e1a | 576 | if (!valid_signal(sig)) |
1da177e4 LT |
577 | return error; |
578 | error = -EPERM; | |
621d3121 | 579 | if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) |
1da177e4 LT |
580 | && ((sig != SIGCONT) || |
581 | (current->signal->session != t->signal->session)) | |
582 | && (current->euid ^ t->suid) && (current->euid ^ t->uid) | |
583 | && (current->uid ^ t->suid) && (current->uid ^ t->uid) | |
584 | && !capable(CAP_KILL)) | |
585 | return error; | |
c2f0c7c3 SG |
586 | |
587 | error = security_task_kill(t, info, sig); | |
588 | if (!error) | |
589 | audit_signal_info(sig, t); /* Let audit system see the signal */ | |
590 | return error; | |
1da177e4 LT |
591 | } |
592 | ||
593 | /* forward decl */ | |
594 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
bc505a47 | 595 | int to_self, |
1da177e4 LT |
596 | int why); |
597 | ||
598 | /* | |
599 | * Handle magic process-wide effects of stop/continue signals. | |
600 | * Unlike the signal actions, these happen immediately at signal-generation | |
601 | * time regardless of blocking, ignoring, or handling. This does the | |
602 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
603 | * signals. The process stop is done as a signal action for SIG_DFL. | |
604 | */ | |
605 | static void handle_stop_signal(int sig, struct task_struct *p) | |
606 | { | |
607 | struct task_struct *t; | |
608 | ||
dd12f48d | 609 | if (p->signal->flags & SIGNAL_GROUP_EXIT) |
1da177e4 LT |
610 | /* |
611 | * The process is in the middle of dying already. | |
612 | */ | |
613 | return; | |
614 | ||
615 | if (sig_kernel_stop(sig)) { | |
616 | /* | |
617 | * This is a stop signal. Remove SIGCONT from all queues. | |
618 | */ | |
619 | rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending); | |
620 | t = p; | |
621 | do { | |
622 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
623 | t = next_thread(t); | |
624 | } while (t != p); | |
625 | } else if (sig == SIGCONT) { | |
626 | /* | |
627 | * Remove all stop signals from all queues, | |
628 | * and wake all threads. | |
629 | */ | |
630 | if (unlikely(p->signal->group_stop_count > 0)) { | |
631 | /* | |
632 | * There was a group stop in progress. We'll | |
633 | * pretend it finished before we got here. We are | |
634 | * obliged to report it to the parent: if the | |
635 | * SIGSTOP happened "after" this SIGCONT, then it | |
636 | * would have cleared this pending SIGCONT. If it | |
637 | * happened "before" this SIGCONT, then the parent | |
638 | * got the SIGCHLD about the stop finishing before | |
639 | * the continue happened. We do the notification | |
640 | * now, and it's as if the stop had finished and | |
641 | * the SIGCHLD was pending on entry to this kill. | |
642 | */ | |
643 | p->signal->group_stop_count = 0; | |
644 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
645 | spin_unlock(&p->sighand->siglock); | |
bc505a47 | 646 | do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_STOPPED); |
1da177e4 LT |
647 | spin_lock(&p->sighand->siglock); |
648 | } | |
649 | rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); | |
650 | t = p; | |
651 | do { | |
652 | unsigned int state; | |
653 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
654 | ||
655 | /* | |
656 | * If there is a handler for SIGCONT, we must make | |
657 | * sure that no thread returns to user mode before | |
658 | * we post the signal, in case it was the only | |
659 | * thread eligible to run the signal handler--then | |
660 | * it must not do anything between resuming and | |
661 | * running the handler. With the TIF_SIGPENDING | |
662 | * flag set, the thread will pause and acquire the | |
663 | * siglock that we hold now and until we've queued | |
664 | * the pending signal. | |
665 | * | |
666 | * Wake up the stopped thread _after_ setting | |
667 | * TIF_SIGPENDING | |
668 | */ | |
669 | state = TASK_STOPPED; | |
670 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { | |
671 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
672 | state |= TASK_INTERRUPTIBLE; | |
673 | } | |
674 | wake_up_state(t, state); | |
675 | ||
676 | t = next_thread(t); | |
677 | } while (t != p); | |
678 | ||
679 | if (p->signal->flags & SIGNAL_STOP_STOPPED) { | |
680 | /* | |
681 | * We were in fact stopped, and are now continued. | |
682 | * Notify the parent with CLD_CONTINUED. | |
683 | */ | |
684 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
685 | p->signal->group_exit_code = 0; | |
686 | spin_unlock(&p->sighand->siglock); | |
bc505a47 | 687 | do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_CONTINUED); |
1da177e4 LT |
688 | spin_lock(&p->sighand->siglock); |
689 | } else { | |
690 | /* | |
691 | * We are not stopped, but there could be a stop | |
692 | * signal in the middle of being processed after | |
693 | * being removed from the queue. Clear that too. | |
694 | */ | |
695 | p->signal->flags = 0; | |
696 | } | |
697 | } else if (sig == SIGKILL) { | |
698 | /* | |
699 | * Make sure that any pending stop signal already dequeued | |
700 | * is undone by the wakeup for SIGKILL. | |
701 | */ | |
702 | p->signal->flags = 0; | |
703 | } | |
704 | } | |
705 | ||
706 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, | |
707 | struct sigpending *signals) | |
708 | { | |
709 | struct sigqueue * q = NULL; | |
710 | int ret = 0; | |
711 | ||
712 | /* | |
713 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
714 | * or SIGKILL. | |
715 | */ | |
b67a1b9e | 716 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
717 | goto out_set; |
718 | ||
719 | /* Real-time signals must be queued if sent by sigqueue, or | |
720 | some other real-time mechanism. It is implementation | |
721 | defined whether kill() does so. We attempt to do so, on | |
722 | the principle of least surprise, but since kill is not | |
723 | allowed to fail with EAGAIN when low on memory we just | |
724 | make sure at least one signal gets delivered and don't | |
725 | pass on the info struct. */ | |
726 | ||
727 | q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN && | |
621d3121 | 728 | (is_si_special(info) || |
1da177e4 LT |
729 | info->si_code >= 0))); |
730 | if (q) { | |
731 | list_add_tail(&q->list, &signals->list); | |
732 | switch ((unsigned long) info) { | |
b67a1b9e | 733 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
734 | q->info.si_signo = sig; |
735 | q->info.si_errno = 0; | |
736 | q->info.si_code = SI_USER; | |
737 | q->info.si_pid = current->pid; | |
738 | q->info.si_uid = current->uid; | |
739 | break; | |
b67a1b9e | 740 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
741 | q->info.si_signo = sig; |
742 | q->info.si_errno = 0; | |
743 | q->info.si_code = SI_KERNEL; | |
744 | q->info.si_pid = 0; | |
745 | q->info.si_uid = 0; | |
746 | break; | |
747 | default: | |
748 | copy_siginfo(&q->info, info); | |
749 | break; | |
750 | } | |
621d3121 ON |
751 | } else if (!is_si_special(info)) { |
752 | if (sig >= SIGRTMIN && info->si_code != SI_USER) | |
1da177e4 LT |
753 | /* |
754 | * Queue overflow, abort. We may abort if the signal was rt | |
755 | * and sent by user using something other than kill(). | |
756 | */ | |
757 | return -EAGAIN; | |
1da177e4 LT |
758 | } |
759 | ||
760 | out_set: | |
761 | sigaddset(&signals->signal, sig); | |
762 | return ret; | |
763 | } | |
764 | ||
765 | #define LEGACY_QUEUE(sigptr, sig) \ | |
766 | (((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig))) | |
767 | ||
768 | ||
769 | static int | |
770 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
771 | { | |
772 | int ret = 0; | |
773 | ||
774 | if (!irqs_disabled()) | |
775 | BUG(); | |
776 | assert_spin_locked(&t->sighand->siglock); | |
777 | ||
1da177e4 LT |
778 | /* Short-circuit ignored signals. */ |
779 | if (sig_ignored(t, sig)) | |
780 | goto out; | |
781 | ||
782 | /* Support queueing exactly one non-rt signal, so that we | |
783 | can get more detailed information about the cause of | |
784 | the signal. */ | |
785 | if (LEGACY_QUEUE(&t->pending, sig)) | |
786 | goto out; | |
787 | ||
788 | ret = send_signal(sig, info, t, &t->pending); | |
789 | if (!ret && !sigismember(&t->blocked, sig)) | |
790 | signal_wake_up(t, sig == SIGKILL); | |
791 | out: | |
792 | return ret; | |
793 | } | |
794 | ||
795 | /* | |
796 | * Force a signal that the process can't ignore: if necessary | |
797 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
798 | */ | |
799 | ||
800 | int | |
801 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
802 | { | |
803 | unsigned long int flags; | |
804 | int ret; | |
805 | ||
806 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
b0423a0d | 807 | if (t->sighand->action[sig-1].sa.sa_handler == SIG_IGN) { |
1da177e4 | 808 | t->sighand->action[sig-1].sa.sa_handler = SIG_DFL; |
b0423a0d PM |
809 | } |
810 | if (sigismember(&t->blocked, sig)) { | |
1da177e4 | 811 | sigdelset(&t->blocked, sig); |
1da177e4 | 812 | } |
b0423a0d | 813 | recalc_sigpending_tsk(t); |
1da177e4 LT |
814 | ret = specific_send_sig_info(sig, info, t); |
815 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
816 | ||
817 | return ret; | |
818 | } | |
819 | ||
820 | void | |
821 | force_sig_specific(int sig, struct task_struct *t) | |
822 | { | |
b0423a0d | 823 | force_sig_info(sig, SEND_SIG_FORCED, t); |
1da177e4 LT |
824 | } |
825 | ||
826 | /* | |
827 | * Test if P wants to take SIG. After we've checked all threads with this, | |
828 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
829 | * blocking SIG were ruled out because they are not running and already | |
830 | * have pending signals. Such threads will dequeue from the shared queue | |
831 | * as soon as they're available, so putting the signal on the shared queue | |
832 | * will be equivalent to sending it to one such thread. | |
833 | */ | |
188a1eaf LT |
834 | static inline int wants_signal(int sig, struct task_struct *p) |
835 | { | |
836 | if (sigismember(&p->blocked, sig)) | |
837 | return 0; | |
838 | if (p->flags & PF_EXITING) | |
839 | return 0; | |
840 | if (sig == SIGKILL) | |
841 | return 1; | |
842 | if (p->state & (TASK_STOPPED | TASK_TRACED)) | |
843 | return 0; | |
844 | return task_curr(p) || !signal_pending(p); | |
845 | } | |
1da177e4 LT |
846 | |
847 | static void | |
848 | __group_complete_signal(int sig, struct task_struct *p) | |
849 | { | |
1da177e4 LT |
850 | struct task_struct *t; |
851 | ||
1da177e4 LT |
852 | /* |
853 | * Now find a thread we can wake up to take the signal off the queue. | |
854 | * | |
855 | * If the main thread wants the signal, it gets first crack. | |
856 | * Probably the least surprising to the average bear. | |
857 | */ | |
188a1eaf | 858 | if (wants_signal(sig, p)) |
1da177e4 LT |
859 | t = p; |
860 | else if (thread_group_empty(p)) | |
861 | /* | |
862 | * There is just one thread and it does not need to be woken. | |
863 | * It will dequeue unblocked signals before it runs again. | |
864 | */ | |
865 | return; | |
866 | else { | |
867 | /* | |
868 | * Otherwise try to find a suitable thread. | |
869 | */ | |
870 | t = p->signal->curr_target; | |
871 | if (t == NULL) | |
872 | /* restart balancing at this thread */ | |
873 | t = p->signal->curr_target = p; | |
874 | BUG_ON(t->tgid != p->tgid); | |
875 | ||
188a1eaf | 876 | while (!wants_signal(sig, t)) { |
1da177e4 LT |
877 | t = next_thread(t); |
878 | if (t == p->signal->curr_target) | |
879 | /* | |
880 | * No thread needs to be woken. | |
881 | * Any eligible threads will see | |
882 | * the signal in the queue soon. | |
883 | */ | |
884 | return; | |
885 | } | |
886 | p->signal->curr_target = t; | |
887 | } | |
888 | ||
889 | /* | |
890 | * Found a killable thread. If the signal will be fatal, | |
891 | * then start taking the whole group down immediately. | |
892 | */ | |
893 | if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) && | |
894 | !sigismember(&t->real_blocked, sig) && | |
895 | (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { | |
896 | /* | |
897 | * This signal will be fatal to the whole group. | |
898 | */ | |
899 | if (!sig_kernel_coredump(sig)) { | |
900 | /* | |
901 | * Start a group exit and wake everybody up. | |
902 | * This way we don't have other threads | |
903 | * running and doing things after a slower | |
904 | * thread has the fatal signal pending. | |
905 | */ | |
906 | p->signal->flags = SIGNAL_GROUP_EXIT; | |
907 | p->signal->group_exit_code = sig; | |
908 | p->signal->group_stop_count = 0; | |
909 | t = p; | |
910 | do { | |
911 | sigaddset(&t->pending.signal, SIGKILL); | |
912 | signal_wake_up(t, 1); | |
913 | t = next_thread(t); | |
914 | } while (t != p); | |
915 | return; | |
916 | } | |
917 | ||
918 | /* | |
919 | * There will be a core dump. We make all threads other | |
920 | * than the chosen one go into a group stop so that nothing | |
921 | * happens until it gets scheduled, takes the signal off | |
922 | * the shared queue, and does the core dump. This is a | |
923 | * little more complicated than strictly necessary, but it | |
924 | * keeps the signal state that winds up in the core dump | |
925 | * unchanged from the death state, e.g. which thread had | |
926 | * the core-dump signal unblocked. | |
927 | */ | |
928 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
929 | rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); | |
930 | p->signal->group_stop_count = 0; | |
931 | p->signal->group_exit_task = t; | |
932 | t = p; | |
933 | do { | |
934 | p->signal->group_stop_count++; | |
935 | signal_wake_up(t, 0); | |
936 | t = next_thread(t); | |
937 | } while (t != p); | |
938 | wake_up_process(p->signal->group_exit_task); | |
939 | return; | |
940 | } | |
941 | ||
942 | /* | |
943 | * The signal is already in the shared-pending queue. | |
944 | * Tell the chosen thread to wake up and dequeue it. | |
945 | */ | |
946 | signal_wake_up(t, sig == SIGKILL); | |
947 | return; | |
948 | } | |
949 | ||
950 | int | |
951 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
952 | { | |
953 | int ret = 0; | |
954 | ||
955 | assert_spin_locked(&p->sighand->siglock); | |
956 | handle_stop_signal(sig, p); | |
957 | ||
1da177e4 LT |
958 | /* Short-circuit ignored signals. */ |
959 | if (sig_ignored(p, sig)) | |
960 | return ret; | |
961 | ||
962 | if (LEGACY_QUEUE(&p->signal->shared_pending, sig)) | |
963 | /* This is a non-RT signal and we already have one queued. */ | |
964 | return ret; | |
965 | ||
966 | /* | |
967 | * Put this signal on the shared-pending queue, or fail with EAGAIN. | |
968 | * We always use the shared queue for process-wide signals, | |
969 | * to avoid several races. | |
970 | */ | |
971 | ret = send_signal(sig, info, p, &p->signal->shared_pending); | |
972 | if (unlikely(ret)) | |
973 | return ret; | |
974 | ||
975 | __group_complete_signal(sig, p); | |
976 | return 0; | |
977 | } | |
978 | ||
979 | /* | |
980 | * Nuke all other threads in the group. | |
981 | */ | |
982 | void zap_other_threads(struct task_struct *p) | |
983 | { | |
984 | struct task_struct *t; | |
985 | ||
986 | p->signal->flags = SIGNAL_GROUP_EXIT; | |
987 | p->signal->group_stop_count = 0; | |
988 | ||
989 | if (thread_group_empty(p)) | |
990 | return; | |
991 | ||
992 | for (t = next_thread(p); t != p; t = next_thread(t)) { | |
993 | /* | |
994 | * Don't bother with already dead threads | |
995 | */ | |
996 | if (t->exit_state) | |
997 | continue; | |
998 | ||
999 | /* | |
1000 | * We don't want to notify the parent, since we are | |
1001 | * killed as part of a thread group due to another | |
1002 | * thread doing an execve() or similar. So set the | |
1003 | * exit signal to -1 to allow immediate reaping of | |
1004 | * the process. But don't detach the thread group | |
1005 | * leader. | |
1006 | */ | |
1007 | if (t != p->group_leader) | |
1008 | t->exit_signal = -1; | |
1009 | ||
30e0fca6 | 1010 | /* SIGKILL will be handled before any pending SIGSTOP */ |
1da177e4 | 1011 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1012 | signal_wake_up(t, 1); |
1013 | } | |
1014 | } | |
1015 | ||
1016 | /* | |
e56d0903 | 1017 | * Must be called under rcu_read_lock() or with tasklist_lock read-held. |
1da177e4 | 1018 | */ |
f63ee72e ON |
1019 | struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) |
1020 | { | |
1021 | struct sighand_struct *sighand; | |
1022 | ||
1023 | for (;;) { | |
1024 | sighand = rcu_dereference(tsk->sighand); | |
1025 | if (unlikely(sighand == NULL)) | |
1026 | break; | |
1027 | ||
1028 | spin_lock_irqsave(&sighand->siglock, *flags); | |
1029 | if (likely(sighand == tsk->sighand)) | |
1030 | break; | |
1031 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
1032 | } | |
1033 | ||
1034 | return sighand; | |
1035 | } | |
1036 | ||
1da177e4 LT |
1037 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1038 | { | |
1039 | unsigned long flags; | |
1040 | int ret; | |
1041 | ||
1042 | ret = check_kill_permission(sig, info, p); | |
f63ee72e ON |
1043 | |
1044 | if (!ret && sig) { | |
1045 | ret = -ESRCH; | |
1046 | if (lock_task_sighand(p, &flags)) { | |
1047 | ret = __group_send_sig_info(sig, info, p); | |
1048 | unlock_task_sighand(p, &flags); | |
2d89c929 | 1049 | } |
1da177e4 LT |
1050 | } |
1051 | ||
1052 | return ret; | |
1053 | } | |
1054 | ||
1055 | /* | |
1056 | * kill_pg_info() sends a signal to a process group: this is what the tty | |
1057 | * control characters do (^C, ^Z etc) | |
1058 | */ | |
1059 | ||
1060 | int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) | |
1061 | { | |
1062 | struct task_struct *p = NULL; | |
1063 | int retval, success; | |
1064 | ||
1065 | if (pgrp <= 0) | |
1066 | return -EINVAL; | |
1067 | ||
1068 | success = 0; | |
1069 | retval = -ESRCH; | |
1070 | do_each_task_pid(pgrp, PIDTYPE_PGID, p) { | |
1071 | int err = group_send_sig_info(sig, info, p); | |
1072 | success |= !err; | |
1073 | retval = err; | |
1074 | } while_each_task_pid(pgrp, PIDTYPE_PGID, p); | |
1075 | return success ? 0 : retval; | |
1076 | } | |
1077 | ||
1078 | int | |
1079 | kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) | |
1080 | { | |
1081 | int retval; | |
1082 | ||
1083 | read_lock(&tasklist_lock); | |
1084 | retval = __kill_pg_info(sig, info, pgrp); | |
1085 | read_unlock(&tasklist_lock); | |
1086 | ||
1087 | return retval; | |
1088 | } | |
1089 | ||
1090 | int | |
1091 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
1092 | { | |
1093 | int error; | |
e56d0903 | 1094 | int acquired_tasklist_lock = 0; |
1da177e4 LT |
1095 | struct task_struct *p; |
1096 | ||
e56d0903 | 1097 | rcu_read_lock(); |
a9e88e84 | 1098 | if (unlikely(sig_needs_tasklist(sig))) { |
e56d0903 IM |
1099 | read_lock(&tasklist_lock); |
1100 | acquired_tasklist_lock = 1; | |
1101 | } | |
1da177e4 LT |
1102 | p = find_task_by_pid(pid); |
1103 | error = -ESRCH; | |
1104 | if (p) | |
1105 | error = group_send_sig_info(sig, info, p); | |
e56d0903 IM |
1106 | if (unlikely(acquired_tasklist_lock)) |
1107 | read_unlock(&tasklist_lock); | |
1108 | rcu_read_unlock(); | |
1da177e4 LT |
1109 | return error; |
1110 | } | |
1111 | ||
46113830 HW |
1112 | /* like kill_proc_info(), but doesn't use uid/euid of "current" */ |
1113 | int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid, | |
1114 | uid_t uid, uid_t euid) | |
1115 | { | |
1116 | int ret = -EINVAL; | |
1117 | struct task_struct *p; | |
1118 | ||
1119 | if (!valid_signal(sig)) | |
1120 | return ret; | |
1121 | ||
1122 | read_lock(&tasklist_lock); | |
1123 | p = find_task_by_pid(pid); | |
1124 | if (!p) { | |
1125 | ret = -ESRCH; | |
1126 | goto out_unlock; | |
1127 | } | |
0811af28 | 1128 | if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) |
46113830 HW |
1129 | && (euid != p->suid) && (euid != p->uid) |
1130 | && (uid != p->suid) && (uid != p->uid)) { | |
1131 | ret = -EPERM; | |
1132 | goto out_unlock; | |
1133 | } | |
1134 | if (sig && p->sighand) { | |
1135 | unsigned long flags; | |
1136 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1137 | ret = __group_send_sig_info(sig, info, p); | |
1138 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1139 | } | |
1140 | out_unlock: | |
1141 | read_unlock(&tasklist_lock); | |
1142 | return ret; | |
1143 | } | |
1144 | EXPORT_SYMBOL_GPL(kill_proc_info_as_uid); | |
1da177e4 LT |
1145 | |
1146 | /* | |
1147 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1148 | * | |
1149 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1150 | * is probably wrong. Should make it like BSD or SYSV. | |
1151 | */ | |
1152 | ||
1153 | static int kill_something_info(int sig, struct siginfo *info, int pid) | |
1154 | { | |
1155 | if (!pid) { | |
1156 | return kill_pg_info(sig, info, process_group(current)); | |
1157 | } else if (pid == -1) { | |
1158 | int retval = 0, count = 0; | |
1159 | struct task_struct * p; | |
1160 | ||
1161 | read_lock(&tasklist_lock); | |
1162 | for_each_process(p) { | |
1163 | if (p->pid > 1 && p->tgid != current->tgid) { | |
1164 | int err = group_send_sig_info(sig, info, p); | |
1165 | ++count; | |
1166 | if (err != -EPERM) | |
1167 | retval = err; | |
1168 | } | |
1169 | } | |
1170 | read_unlock(&tasklist_lock); | |
1171 | return count ? retval : -ESRCH; | |
1172 | } else if (pid < 0) { | |
1173 | return kill_pg_info(sig, info, -pid); | |
1174 | } else { | |
1175 | return kill_proc_info(sig, info, pid); | |
1176 | } | |
1177 | } | |
1178 | ||
1179 | /* | |
1180 | * These are for backward compatibility with the rest of the kernel source. | |
1181 | */ | |
1182 | ||
1183 | /* | |
1184 | * These two are the most common entry points. They send a signal | |
1185 | * just to the specific thread. | |
1186 | */ | |
1187 | int | |
1188 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1189 | { | |
1190 | int ret; | |
1191 | unsigned long flags; | |
1192 | ||
1193 | /* | |
1194 | * Make sure legacy kernel users don't send in bad values | |
1195 | * (normal paths check this in check_kill_permission). | |
1196 | */ | |
7ed20e1a | 1197 | if (!valid_signal(sig)) |
1da177e4 LT |
1198 | return -EINVAL; |
1199 | ||
1200 | /* | |
1201 | * We need the tasklist lock even for the specific | |
1202 | * thread case (when we don't need to follow the group | |
1203 | * lists) in order to avoid races with "p->sighand" | |
1204 | * going away or changing from under us. | |
1205 | */ | |
1206 | read_lock(&tasklist_lock); | |
1207 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1208 | ret = specific_send_sig_info(sig, info, p); | |
1209 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1210 | read_unlock(&tasklist_lock); | |
1211 | return ret; | |
1212 | } | |
1213 | ||
b67a1b9e ON |
1214 | #define __si_special(priv) \ |
1215 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1216 | ||
1da177e4 LT |
1217 | int |
1218 | send_sig(int sig, struct task_struct *p, int priv) | |
1219 | { | |
b67a1b9e | 1220 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1221 | } |
1222 | ||
1223 | /* | |
1224 | * This is the entry point for "process-wide" signals. | |
1225 | * They will go to an appropriate thread in the thread group. | |
1226 | */ | |
1227 | int | |
1228 | send_group_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1229 | { | |
1230 | int ret; | |
1231 | read_lock(&tasklist_lock); | |
1232 | ret = group_send_sig_info(sig, info, p); | |
1233 | read_unlock(&tasklist_lock); | |
1234 | return ret; | |
1235 | } | |
1236 | ||
1237 | void | |
1238 | force_sig(int sig, struct task_struct *p) | |
1239 | { | |
b67a1b9e | 1240 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1241 | } |
1242 | ||
1243 | /* | |
1244 | * When things go south during signal handling, we | |
1245 | * will force a SIGSEGV. And if the signal that caused | |
1246 | * the problem was already a SIGSEGV, we'll want to | |
1247 | * make sure we don't even try to deliver the signal.. | |
1248 | */ | |
1249 | int | |
1250 | force_sigsegv(int sig, struct task_struct *p) | |
1251 | { | |
1252 | if (sig == SIGSEGV) { | |
1253 | unsigned long flags; | |
1254 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1255 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1256 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1257 | } | |
1258 | force_sig(SIGSEGV, p); | |
1259 | return 0; | |
1260 | } | |
1261 | ||
1262 | int | |
1263 | kill_pg(pid_t pgrp, int sig, int priv) | |
1264 | { | |
b67a1b9e | 1265 | return kill_pg_info(sig, __si_special(priv), pgrp); |
1da177e4 LT |
1266 | } |
1267 | ||
1268 | int | |
1269 | kill_proc(pid_t pid, int sig, int priv) | |
1270 | { | |
b67a1b9e | 1271 | return kill_proc_info(sig, __si_special(priv), pid); |
1da177e4 LT |
1272 | } |
1273 | ||
1274 | /* | |
1275 | * These functions support sending signals using preallocated sigqueue | |
1276 | * structures. This is needed "because realtime applications cannot | |
1277 | * afford to lose notifications of asynchronous events, like timer | |
1278 | * expirations or I/O completions". In the case of Posix Timers | |
1279 | * we allocate the sigqueue structure from the timer_create. If this | |
1280 | * allocation fails we are able to report the failure to the application | |
1281 | * with an EAGAIN error. | |
1282 | */ | |
1283 | ||
1284 | struct sigqueue *sigqueue_alloc(void) | |
1285 | { | |
1286 | struct sigqueue *q; | |
1287 | ||
1288 | if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) | |
1289 | q->flags |= SIGQUEUE_PREALLOC; | |
1290 | return(q); | |
1291 | } | |
1292 | ||
1293 | void sigqueue_free(struct sigqueue *q) | |
1294 | { | |
1295 | unsigned long flags; | |
1296 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); | |
1297 | /* | |
1298 | * If the signal is still pending remove it from the | |
1299 | * pending queue. | |
1300 | */ | |
1301 | if (unlikely(!list_empty(&q->list))) { | |
19a4fcb5 ON |
1302 | spinlock_t *lock = ¤t->sighand->siglock; |
1303 | read_lock(&tasklist_lock); | |
1304 | spin_lock_irqsave(lock, flags); | |
1da177e4 LT |
1305 | if (!list_empty(&q->list)) |
1306 | list_del_init(&q->list); | |
19a4fcb5 | 1307 | spin_unlock_irqrestore(lock, flags); |
1da177e4 LT |
1308 | read_unlock(&tasklist_lock); |
1309 | } | |
1310 | q->flags &= ~SIGQUEUE_PREALLOC; | |
1311 | __sigqueue_free(q); | |
1312 | } | |
1313 | ||
1314 | int | |
1315 | send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) | |
1316 | { | |
1317 | unsigned long flags; | |
1318 | int ret = 0; | |
e56d0903 | 1319 | struct sighand_struct *sh; |
1da177e4 | 1320 | |
1da177e4 | 1321 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e56d0903 IM |
1322 | |
1323 | /* | |
1324 | * The rcu based delayed sighand destroy makes it possible to | |
1325 | * run this without tasklist lock held. The task struct itself | |
1326 | * cannot go away as create_timer did get_task_struct(). | |
1327 | * | |
1328 | * We return -1, when the task is marked exiting, so | |
1329 | * posix_timer_event can redirect it to the group leader | |
1330 | */ | |
1331 | rcu_read_lock(); | |
e752dd6c ON |
1332 | |
1333 | if (unlikely(p->flags & PF_EXITING)) { | |
1334 | ret = -1; | |
1335 | goto out_err; | |
1336 | } | |
1337 | ||
e56d0903 IM |
1338 | retry: |
1339 | sh = rcu_dereference(p->sighand); | |
1340 | ||
1341 | spin_lock_irqsave(&sh->siglock, flags); | |
1342 | if (p->sighand != sh) { | |
1343 | /* We raced with exec() in a multithreaded process... */ | |
1344 | spin_unlock_irqrestore(&sh->siglock, flags); | |
1345 | goto retry; | |
1346 | } | |
1347 | ||
1348 | /* | |
1349 | * We do the check here again to handle the following scenario: | |
1350 | * | |
1351 | * CPU 0 CPU 1 | |
1352 | * send_sigqueue | |
1353 | * check PF_EXITING | |
1354 | * interrupt exit code running | |
1355 | * __exit_signal | |
1356 | * lock sighand->siglock | |
1357 | * unlock sighand->siglock | |
1358 | * lock sh->siglock | |
1359 | * add(tsk->pending) flush_sigqueue(tsk->pending) | |
1360 | * | |
1361 | */ | |
1362 | ||
1363 | if (unlikely(p->flags & PF_EXITING)) { | |
1364 | ret = -1; | |
1365 | goto out; | |
1366 | } | |
e752dd6c | 1367 | |
1da177e4 LT |
1368 | if (unlikely(!list_empty(&q->list))) { |
1369 | /* | |
1370 | * If an SI_TIMER entry is already queue just increment | |
1371 | * the overrun count. | |
1372 | */ | |
1373 | if (q->info.si_code != SI_TIMER) | |
1374 | BUG(); | |
1375 | q->info.si_overrun++; | |
1376 | goto out; | |
e752dd6c | 1377 | } |
1da177e4 LT |
1378 | /* Short-circuit ignored signals. */ |
1379 | if (sig_ignored(p, sig)) { | |
1380 | ret = 1; | |
1381 | goto out; | |
1382 | } | |
1383 | ||
1da177e4 LT |
1384 | list_add_tail(&q->list, &p->pending.list); |
1385 | sigaddset(&p->pending.signal, sig); | |
1386 | if (!sigismember(&p->blocked, sig)) | |
1387 | signal_wake_up(p, sig == SIGKILL); | |
1388 | ||
1389 | out: | |
e56d0903 | 1390 | spin_unlock_irqrestore(&sh->siglock, flags); |
e752dd6c | 1391 | out_err: |
e56d0903 | 1392 | rcu_read_unlock(); |
e752dd6c ON |
1393 | |
1394 | return ret; | |
1da177e4 LT |
1395 | } |
1396 | ||
1397 | int | |
1398 | send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) | |
1399 | { | |
1400 | unsigned long flags; | |
1401 | int ret = 0; | |
1402 | ||
1403 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); | |
e56d0903 | 1404 | |
1da177e4 | 1405 | read_lock(&tasklist_lock); |
e56d0903 | 1406 | /* Since it_lock is held, p->sighand cannot be NULL. */ |
1da177e4 LT |
1407 | spin_lock_irqsave(&p->sighand->siglock, flags); |
1408 | handle_stop_signal(sig, p); | |
1409 | ||
1410 | /* Short-circuit ignored signals. */ | |
1411 | if (sig_ignored(p, sig)) { | |
1412 | ret = 1; | |
1413 | goto out; | |
1414 | } | |
1415 | ||
1416 | if (unlikely(!list_empty(&q->list))) { | |
1417 | /* | |
1418 | * If an SI_TIMER entry is already queue just increment | |
1419 | * the overrun count. Other uses should not try to | |
1420 | * send the signal multiple times. | |
1421 | */ | |
1422 | if (q->info.si_code != SI_TIMER) | |
1423 | BUG(); | |
1424 | q->info.si_overrun++; | |
1425 | goto out; | |
1426 | } | |
1427 | ||
1428 | /* | |
1429 | * Put this signal on the shared-pending queue. | |
1430 | * We always use the shared queue for process-wide signals, | |
1431 | * to avoid several races. | |
1432 | */ | |
1da177e4 LT |
1433 | list_add_tail(&q->list, &p->signal->shared_pending.list); |
1434 | sigaddset(&p->signal->shared_pending.signal, sig); | |
1435 | ||
1436 | __group_complete_signal(sig, p); | |
1437 | out: | |
1438 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1439 | read_unlock(&tasklist_lock); | |
e56d0903 | 1440 | return ret; |
1da177e4 LT |
1441 | } |
1442 | ||
1443 | /* | |
1444 | * Wake up any threads in the parent blocked in wait* syscalls. | |
1445 | */ | |
1446 | static inline void __wake_up_parent(struct task_struct *p, | |
1447 | struct task_struct *parent) | |
1448 | { | |
1449 | wake_up_interruptible_sync(&parent->signal->wait_chldexit); | |
1450 | } | |
1451 | ||
1452 | /* | |
1453 | * Let a parent know about the death of a child. | |
1454 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
1455 | */ | |
1456 | ||
1457 | void do_notify_parent(struct task_struct *tsk, int sig) | |
1458 | { | |
1459 | struct siginfo info; | |
1460 | unsigned long flags; | |
1461 | struct sighand_struct *psig; | |
1462 | ||
1463 | BUG_ON(sig == -1); | |
1464 | ||
1465 | /* do_notify_parent_cldstop should have been called instead. */ | |
1466 | BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); | |
1467 | ||
1468 | BUG_ON(!tsk->ptrace && | |
1469 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); | |
1470 | ||
1471 | info.si_signo = sig; | |
1472 | info.si_errno = 0; | |
1473 | info.si_pid = tsk->pid; | |
1474 | info.si_uid = tsk->uid; | |
1475 | ||
1476 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1477 | info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime, | |
1478 | tsk->signal->utime)); | |
1479 | info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime, | |
1480 | tsk->signal->stime)); | |
1481 | ||
1482 | info.si_status = tsk->exit_code & 0x7f; | |
1483 | if (tsk->exit_code & 0x80) | |
1484 | info.si_code = CLD_DUMPED; | |
1485 | else if (tsk->exit_code & 0x7f) | |
1486 | info.si_code = CLD_KILLED; | |
1487 | else { | |
1488 | info.si_code = CLD_EXITED; | |
1489 | info.si_status = tsk->exit_code >> 8; | |
1490 | } | |
1491 | ||
1492 | psig = tsk->parent->sighand; | |
1493 | spin_lock_irqsave(&psig->siglock, flags); | |
7ed0175a | 1494 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1495 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1496 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1497 | /* | |
1498 | * We are exiting and our parent doesn't care. POSIX.1 | |
1499 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1500 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1501 | * automatically and not left for our parent's wait4 call. | |
1502 | * Rather than having the parent do it as a magic kind of | |
1503 | * signal handler, we just set this to tell do_exit that we | |
1504 | * can be cleaned up without becoming a zombie. Note that | |
1505 | * we still call __wake_up_parent in this case, because a | |
1506 | * blocked sys_wait4 might now return -ECHILD. | |
1507 | * | |
1508 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1509 | * is implementation-defined: we do (if you don't want | |
1510 | * it, just use SIG_IGN instead). | |
1511 | */ | |
1512 | tsk->exit_signal = -1; | |
1513 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) | |
1514 | sig = 0; | |
1515 | } | |
7ed20e1a | 1516 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1517 | __group_send_sig_info(sig, &info, tsk->parent); |
1518 | __wake_up_parent(tsk, tsk->parent); | |
1519 | spin_unlock_irqrestore(&psig->siglock, flags); | |
1520 | } | |
1521 | ||
bc505a47 | 1522 | static void do_notify_parent_cldstop(struct task_struct *tsk, int to_self, int why) |
1da177e4 LT |
1523 | { |
1524 | struct siginfo info; | |
1525 | unsigned long flags; | |
bc505a47 | 1526 | struct task_struct *parent; |
1da177e4 LT |
1527 | struct sighand_struct *sighand; |
1528 | ||
bc505a47 ON |
1529 | if (to_self) |
1530 | parent = tsk->parent; | |
1531 | else { | |
1532 | tsk = tsk->group_leader; | |
1533 | parent = tsk->real_parent; | |
1534 | } | |
1535 | ||
1da177e4 LT |
1536 | info.si_signo = SIGCHLD; |
1537 | info.si_errno = 0; | |
1538 | info.si_pid = tsk->pid; | |
1539 | info.si_uid = tsk->uid; | |
1540 | ||
1541 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1542 | info.si_utime = cputime_to_jiffies(tsk->utime); | |
1543 | info.si_stime = cputime_to_jiffies(tsk->stime); | |
1544 | ||
1545 | info.si_code = why; | |
1546 | switch (why) { | |
1547 | case CLD_CONTINUED: | |
1548 | info.si_status = SIGCONT; | |
1549 | break; | |
1550 | case CLD_STOPPED: | |
1551 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1552 | break; | |
1553 | case CLD_TRAPPED: | |
1554 | info.si_status = tsk->exit_code & 0x7f; | |
1555 | break; | |
1556 | default: | |
1557 | BUG(); | |
1558 | } | |
1559 | ||
1560 | sighand = parent->sighand; | |
1561 | spin_lock_irqsave(&sighand->siglock, flags); | |
1562 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1563 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1564 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1565 | /* | |
1566 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1567 | */ | |
1568 | __wake_up_parent(tsk, parent); | |
1569 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1570 | } | |
1571 | ||
1572 | /* | |
1573 | * This must be called with current->sighand->siglock held. | |
1574 | * | |
1575 | * This should be the path for all ptrace stops. | |
1576 | * We always set current->last_siginfo while stopped here. | |
1577 | * That makes it a way to test a stopped process for | |
1578 | * being ptrace-stopped vs being job-control-stopped. | |
1579 | * | |
1580 | * If we actually decide not to stop at all because the tracer is gone, | |
1581 | * we leave nostop_code in current->exit_code. | |
1582 | */ | |
1583 | static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) | |
1584 | { | |
1585 | /* | |
1586 | * If there is a group stop in progress, | |
1587 | * we must participate in the bookkeeping. | |
1588 | */ | |
1589 | if (current->signal->group_stop_count > 0) | |
1590 | --current->signal->group_stop_count; | |
1591 | ||
1592 | current->last_siginfo = info; | |
1593 | current->exit_code = exit_code; | |
1594 | ||
1595 | /* Let the debugger run. */ | |
1596 | set_current_state(TASK_TRACED); | |
1597 | spin_unlock_irq(¤t->sighand->siglock); | |
1598 | read_lock(&tasklist_lock); | |
1599 | if (likely(current->ptrace & PT_PTRACED) && | |
1600 | likely(current->parent != current->real_parent || | |
1601 | !(current->ptrace & PT_ATTACHED)) && | |
1602 | (likely(current->parent->signal != current->signal) || | |
1603 | !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) { | |
bc505a47 | 1604 | do_notify_parent_cldstop(current, 1, CLD_TRAPPED); |
1da177e4 LT |
1605 | read_unlock(&tasklist_lock); |
1606 | schedule(); | |
1607 | } else { | |
1608 | /* | |
1609 | * By the time we got the lock, our tracer went away. | |
1610 | * Don't stop here. | |
1611 | */ | |
1612 | read_unlock(&tasklist_lock); | |
1613 | set_current_state(TASK_RUNNING); | |
1614 | current->exit_code = nostop_code; | |
1615 | } | |
1616 | ||
1617 | /* | |
1618 | * We are back. Now reacquire the siglock before touching | |
1619 | * last_siginfo, so that we are sure to have synchronized with | |
1620 | * any signal-sending on another CPU that wants to examine it. | |
1621 | */ | |
1622 | spin_lock_irq(¤t->sighand->siglock); | |
1623 | current->last_siginfo = NULL; | |
1624 | ||
1625 | /* | |
1626 | * Queued signals ignored us while we were stopped for tracing. | |
1627 | * So check for any that we should take before resuming user mode. | |
1628 | */ | |
1629 | recalc_sigpending(); | |
1630 | } | |
1631 | ||
1632 | void ptrace_notify(int exit_code) | |
1633 | { | |
1634 | siginfo_t info; | |
1635 | ||
1636 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1637 | ||
1638 | memset(&info, 0, sizeof info); | |
1639 | info.si_signo = SIGTRAP; | |
1640 | info.si_code = exit_code; | |
1641 | info.si_pid = current->pid; | |
1642 | info.si_uid = current->uid; | |
1643 | ||
1644 | /* Let the debugger run. */ | |
1645 | spin_lock_irq(¤t->sighand->siglock); | |
1646 | ptrace_stop(exit_code, 0, &info); | |
1647 | spin_unlock_irq(¤t->sighand->siglock); | |
1648 | } | |
1649 | ||
1da177e4 LT |
1650 | static void |
1651 | finish_stop(int stop_count) | |
1652 | { | |
bc505a47 ON |
1653 | int to_self; |
1654 | ||
1da177e4 LT |
1655 | /* |
1656 | * If there are no other threads in the group, or if there is | |
1657 | * a group stop in progress and we are the last to stop, | |
1658 | * report to the parent. When ptraced, every thread reports itself. | |
1659 | */ | |
883606a7 | 1660 | if (current->ptrace & PT_PTRACED) |
bc505a47 ON |
1661 | to_self = 1; |
1662 | else if (stop_count == 0) | |
1663 | to_self = 0; | |
1664 | else | |
1665 | goto out; | |
1da177e4 | 1666 | |
bc505a47 ON |
1667 | read_lock(&tasklist_lock); |
1668 | do_notify_parent_cldstop(current, to_self, CLD_STOPPED); | |
1669 | read_unlock(&tasklist_lock); | |
1670 | ||
1671 | out: | |
1da177e4 LT |
1672 | schedule(); |
1673 | /* | |
1674 | * Now we don't run again until continued. | |
1675 | */ | |
1676 | current->exit_code = 0; | |
1677 | } | |
1678 | ||
1679 | /* | |
1680 | * This performs the stopping for SIGSTOP and other stop signals. | |
1681 | * We have to stop all threads in the thread group. | |
1682 | * Returns nonzero if we've actually stopped and released the siglock. | |
1683 | * Returns zero if we didn't stop and still hold the siglock. | |
1684 | */ | |
a122b341 | 1685 | static int do_signal_stop(int signr) |
1da177e4 LT |
1686 | { |
1687 | struct signal_struct *sig = current->signal; | |
dac27f4a | 1688 | int stop_count; |
1da177e4 LT |
1689 | |
1690 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) | |
1691 | return 0; | |
1692 | ||
1693 | if (sig->group_stop_count > 0) { | |
1694 | /* | |
1695 | * There is a group stop in progress. We don't need to | |
1696 | * start another one. | |
1697 | */ | |
1da177e4 | 1698 | stop_count = --sig->group_stop_count; |
dac27f4a | 1699 | } else { |
1da177e4 LT |
1700 | /* |
1701 | * There is no group stop already in progress. | |
a122b341 | 1702 | * We must initiate one now. |
1da177e4 LT |
1703 | */ |
1704 | struct task_struct *t; | |
1705 | ||
a122b341 | 1706 | sig->group_exit_code = signr; |
1da177e4 | 1707 | |
a122b341 ON |
1708 | stop_count = 0; |
1709 | for (t = next_thread(current); t != current; t = next_thread(t)) | |
1da177e4 | 1710 | /* |
a122b341 ON |
1711 | * Setting state to TASK_STOPPED for a group |
1712 | * stop is always done with the siglock held, | |
1713 | * so this check has no races. | |
1da177e4 | 1714 | */ |
a122b341 ON |
1715 | if (!t->exit_state && |
1716 | !(t->state & (TASK_STOPPED|TASK_TRACED))) { | |
1717 | stop_count++; | |
1718 | signal_wake_up(t, 0); | |
1719 | } | |
1720 | sig->group_stop_count = stop_count; | |
1da177e4 LT |
1721 | } |
1722 | ||
dac27f4a ON |
1723 | if (stop_count == 0) |
1724 | sig->flags = SIGNAL_STOP_STOPPED; | |
1725 | current->exit_code = sig->group_exit_code; | |
1726 | __set_current_state(TASK_STOPPED); | |
1727 | ||
1728 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
1729 | finish_stop(stop_count); |
1730 | return 1; | |
1731 | } | |
1732 | ||
1733 | /* | |
1734 | * Do appropriate magic when group_stop_count > 0. | |
1735 | * We return nonzero if we stopped, after releasing the siglock. | |
1736 | * We return zero if we still hold the siglock and should look | |
1737 | * for another signal without checking group_stop_count again. | |
1738 | */ | |
858119e1 | 1739 | static int handle_group_stop(void) |
1da177e4 LT |
1740 | { |
1741 | int stop_count; | |
1742 | ||
1743 | if (current->signal->group_exit_task == current) { | |
1744 | /* | |
1745 | * Group stop is so we can do a core dump, | |
1746 | * We are the initiating thread, so get on with it. | |
1747 | */ | |
1748 | current->signal->group_exit_task = NULL; | |
1749 | return 0; | |
1750 | } | |
1751 | ||
1752 | if (current->signal->flags & SIGNAL_GROUP_EXIT) | |
1753 | /* | |
1754 | * Group stop is so another thread can do a core dump, | |
1755 | * or else we are racing against a death signal. | |
1756 | * Just punt the stop so we can get the next signal. | |
1757 | */ | |
1758 | return 0; | |
1759 | ||
1760 | /* | |
1761 | * There is a group stop in progress. We stop | |
1762 | * without any associated signal being in our queue. | |
1763 | */ | |
1764 | stop_count = --current->signal->group_stop_count; | |
1765 | if (stop_count == 0) | |
1766 | current->signal->flags = SIGNAL_STOP_STOPPED; | |
1767 | current->exit_code = current->signal->group_exit_code; | |
1768 | set_current_state(TASK_STOPPED); | |
1769 | spin_unlock_irq(¤t->sighand->siglock); | |
1770 | finish_stop(stop_count); | |
1771 | return 1; | |
1772 | } | |
1773 | ||
1774 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, | |
1775 | struct pt_regs *regs, void *cookie) | |
1776 | { | |
1777 | sigset_t *mask = ¤t->blocked; | |
1778 | int signr = 0; | |
1779 | ||
fc558a74 RW |
1780 | try_to_freeze(); |
1781 | ||
1da177e4 LT |
1782 | relock: |
1783 | spin_lock_irq(¤t->sighand->siglock); | |
1784 | for (;;) { | |
1785 | struct k_sigaction *ka; | |
1786 | ||
1787 | if (unlikely(current->signal->group_stop_count > 0) && | |
1788 | handle_group_stop()) | |
1789 | goto relock; | |
1790 | ||
1791 | signr = dequeue_signal(current, mask, info); | |
1792 | ||
1793 | if (!signr) | |
1794 | break; /* will return 0 */ | |
1795 | ||
1796 | if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) { | |
1797 | ptrace_signal_deliver(regs, cookie); | |
1798 | ||
1799 | /* Let the debugger run. */ | |
1800 | ptrace_stop(signr, signr, info); | |
1801 | ||
30e0fca6 | 1802 | /* We're back. Did the debugger cancel the sig or group_exit? */ |
1da177e4 | 1803 | signr = current->exit_code; |
30e0fca6 | 1804 | if (signr == 0 || current->signal->flags & SIGNAL_GROUP_EXIT) |
1da177e4 LT |
1805 | continue; |
1806 | ||
1807 | current->exit_code = 0; | |
1808 | ||
1809 | /* Update the siginfo structure if the signal has | |
1810 | changed. If the debugger wanted something | |
1811 | specific in the siginfo structure then it should | |
1812 | have updated *info via PTRACE_SETSIGINFO. */ | |
1813 | if (signr != info->si_signo) { | |
1814 | info->si_signo = signr; | |
1815 | info->si_errno = 0; | |
1816 | info->si_code = SI_USER; | |
1817 | info->si_pid = current->parent->pid; | |
1818 | info->si_uid = current->parent->uid; | |
1819 | } | |
1820 | ||
1821 | /* If the (new) signal is now blocked, requeue it. */ | |
1822 | if (sigismember(¤t->blocked, signr)) { | |
1823 | specific_send_sig_info(signr, info, current); | |
1824 | continue; | |
1825 | } | |
1826 | } | |
1827 | ||
1828 | ka = ¤t->sighand->action[signr-1]; | |
1829 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ | |
1830 | continue; | |
1831 | if (ka->sa.sa_handler != SIG_DFL) { | |
1832 | /* Run the handler. */ | |
1833 | *return_ka = *ka; | |
1834 | ||
1835 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1836 | ka->sa.sa_handler = SIG_DFL; | |
1837 | ||
1838 | break; /* will return non-zero "signr" value */ | |
1839 | } | |
1840 | ||
1841 | /* | |
1842 | * Now we are doing the default action for this signal. | |
1843 | */ | |
1844 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1845 | continue; | |
1846 | ||
1847 | /* Init gets no signals it doesn't want. */ | |
fef23e7f | 1848 | if (current == child_reaper) |
1da177e4 LT |
1849 | continue; |
1850 | ||
1851 | if (sig_kernel_stop(signr)) { | |
1852 | /* | |
1853 | * The default action is to stop all threads in | |
1854 | * the thread group. The job control signals | |
1855 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1856 | * always works. Note that siglock needs to be | |
1857 | * dropped during the call to is_orphaned_pgrp() | |
1858 | * because of lock ordering with tasklist_lock. | |
1859 | * This allows an intervening SIGCONT to be posted. | |
1860 | * We need to check for that and bail out if necessary. | |
1861 | */ | |
1862 | if (signr != SIGSTOP) { | |
1863 | spin_unlock_irq(¤t->sighand->siglock); | |
1864 | ||
1865 | /* signals can be posted during this window */ | |
1866 | ||
1867 | if (is_orphaned_pgrp(process_group(current))) | |
1868 | goto relock; | |
1869 | ||
1870 | spin_lock_irq(¤t->sighand->siglock); | |
1871 | } | |
1872 | ||
1873 | if (likely(do_signal_stop(signr))) { | |
1874 | /* It released the siglock. */ | |
1875 | goto relock; | |
1876 | } | |
1877 | ||
1878 | /* | |
1879 | * We didn't actually stop, due to a race | |
1880 | * with SIGCONT or something like that. | |
1881 | */ | |
1882 | continue; | |
1883 | } | |
1884 | ||
1885 | spin_unlock_irq(¤t->sighand->siglock); | |
1886 | ||
1887 | /* | |
1888 | * Anything else is fatal, maybe with a core dump. | |
1889 | */ | |
1890 | current->flags |= PF_SIGNALED; | |
1891 | if (sig_kernel_coredump(signr)) { | |
1892 | /* | |
1893 | * If it was able to dump core, this kills all | |
1894 | * other threads in the group and synchronizes with | |
1895 | * their demise. If we lost the race with another | |
1896 | * thread getting here, it set group_exit_code | |
1897 | * first and our do_group_exit call below will use | |
1898 | * that value and ignore the one we pass it. | |
1899 | */ | |
1900 | do_coredump((long)signr, signr, regs); | |
1901 | } | |
1902 | ||
1903 | /* | |
1904 | * Death signals, no core dump. | |
1905 | */ | |
1906 | do_group_exit(signr); | |
1907 | /* NOTREACHED */ | |
1908 | } | |
1909 | spin_unlock_irq(¤t->sighand->siglock); | |
1910 | return signr; | |
1911 | } | |
1912 | ||
1da177e4 LT |
1913 | EXPORT_SYMBOL(recalc_sigpending); |
1914 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
1915 | EXPORT_SYMBOL(flush_signals); | |
1916 | EXPORT_SYMBOL(force_sig); | |
1917 | EXPORT_SYMBOL(kill_pg); | |
1918 | EXPORT_SYMBOL(kill_proc); | |
1919 | EXPORT_SYMBOL(ptrace_notify); | |
1920 | EXPORT_SYMBOL(send_sig); | |
1921 | EXPORT_SYMBOL(send_sig_info); | |
1922 | EXPORT_SYMBOL(sigprocmask); | |
1923 | EXPORT_SYMBOL(block_all_signals); | |
1924 | EXPORT_SYMBOL(unblock_all_signals); | |
1925 | ||
1926 | ||
1927 | /* | |
1928 | * System call entry points. | |
1929 | */ | |
1930 | ||
1931 | asmlinkage long sys_restart_syscall(void) | |
1932 | { | |
1933 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
1934 | return restart->fn(restart); | |
1935 | } | |
1936 | ||
1937 | long do_no_restart_syscall(struct restart_block *param) | |
1938 | { | |
1939 | return -EINTR; | |
1940 | } | |
1941 | ||
1942 | /* | |
1943 | * We don't need to get the kernel lock - this is all local to this | |
1944 | * particular thread.. (and that's good, because this is _heavily_ | |
1945 | * used by various programs) | |
1946 | */ | |
1947 | ||
1948 | /* | |
1949 | * This is also useful for kernel threads that want to temporarily | |
1950 | * (or permanently) block certain signals. | |
1951 | * | |
1952 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
1953 | * interface happily blocks "unblockable" signals like SIGKILL | |
1954 | * and friends. | |
1955 | */ | |
1956 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
1957 | { | |
1958 | int error; | |
1da177e4 LT |
1959 | |
1960 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
1961 | if (oldset) |
1962 | *oldset = current->blocked; | |
1963 | ||
1da177e4 LT |
1964 | error = 0; |
1965 | switch (how) { | |
1966 | case SIG_BLOCK: | |
1967 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
1968 | break; | |
1969 | case SIG_UNBLOCK: | |
1970 | signandsets(¤t->blocked, ¤t->blocked, set); | |
1971 | break; | |
1972 | case SIG_SETMASK: | |
1973 | current->blocked = *set; | |
1974 | break; | |
1975 | default: | |
1976 | error = -EINVAL; | |
1977 | } | |
1978 | recalc_sigpending(); | |
1979 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 1980 | |
1da177e4 LT |
1981 | return error; |
1982 | } | |
1983 | ||
1984 | asmlinkage long | |
1985 | sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize) | |
1986 | { | |
1987 | int error = -EINVAL; | |
1988 | sigset_t old_set, new_set; | |
1989 | ||
1990 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
1991 | if (sigsetsize != sizeof(sigset_t)) | |
1992 | goto out; | |
1993 | ||
1994 | if (set) { | |
1995 | error = -EFAULT; | |
1996 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
1997 | goto out; | |
1998 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
1999 | ||
2000 | error = sigprocmask(how, &new_set, &old_set); | |
2001 | if (error) | |
2002 | goto out; | |
2003 | if (oset) | |
2004 | goto set_old; | |
2005 | } else if (oset) { | |
2006 | spin_lock_irq(¤t->sighand->siglock); | |
2007 | old_set = current->blocked; | |
2008 | spin_unlock_irq(¤t->sighand->siglock); | |
2009 | ||
2010 | set_old: | |
2011 | error = -EFAULT; | |
2012 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2013 | goto out; | |
2014 | } | |
2015 | error = 0; | |
2016 | out: | |
2017 | return error; | |
2018 | } | |
2019 | ||
2020 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2021 | { | |
2022 | long error = -EINVAL; | |
2023 | sigset_t pending; | |
2024 | ||
2025 | if (sigsetsize > sizeof(sigset_t)) | |
2026 | goto out; | |
2027 | ||
2028 | spin_lock_irq(¤t->sighand->siglock); | |
2029 | sigorsets(&pending, ¤t->pending.signal, | |
2030 | ¤t->signal->shared_pending.signal); | |
2031 | spin_unlock_irq(¤t->sighand->siglock); | |
2032 | ||
2033 | /* Outside the lock because only this thread touches it. */ | |
2034 | sigandsets(&pending, ¤t->blocked, &pending); | |
2035 | ||
2036 | error = -EFAULT; | |
2037 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2038 | error = 0; | |
2039 | ||
2040 | out: | |
2041 | return error; | |
2042 | } | |
2043 | ||
2044 | asmlinkage long | |
2045 | sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize) | |
2046 | { | |
2047 | return do_sigpending(set, sigsetsize); | |
2048 | } | |
2049 | ||
2050 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2051 | ||
2052 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2053 | { | |
2054 | int err; | |
2055 | ||
2056 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2057 | return -EFAULT; | |
2058 | if (from->si_code < 0) | |
2059 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2060 | ? -EFAULT : 0; | |
2061 | /* | |
2062 | * If you change siginfo_t structure, please be sure | |
2063 | * this code is fixed accordingly. | |
2064 | * It should never copy any pad contained in the structure | |
2065 | * to avoid security leaks, but must copy the generic | |
2066 | * 3 ints plus the relevant union member. | |
2067 | */ | |
2068 | err = __put_user(from->si_signo, &to->si_signo); | |
2069 | err |= __put_user(from->si_errno, &to->si_errno); | |
2070 | err |= __put_user((short)from->si_code, &to->si_code); | |
2071 | switch (from->si_code & __SI_MASK) { | |
2072 | case __SI_KILL: | |
2073 | err |= __put_user(from->si_pid, &to->si_pid); | |
2074 | err |= __put_user(from->si_uid, &to->si_uid); | |
2075 | break; | |
2076 | case __SI_TIMER: | |
2077 | err |= __put_user(from->si_tid, &to->si_tid); | |
2078 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2079 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2080 | break; | |
2081 | case __SI_POLL: | |
2082 | err |= __put_user(from->si_band, &to->si_band); | |
2083 | err |= __put_user(from->si_fd, &to->si_fd); | |
2084 | break; | |
2085 | case __SI_FAULT: | |
2086 | err |= __put_user(from->si_addr, &to->si_addr); | |
2087 | #ifdef __ARCH_SI_TRAPNO | |
2088 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
2089 | #endif | |
2090 | break; | |
2091 | case __SI_CHLD: | |
2092 | err |= __put_user(from->si_pid, &to->si_pid); | |
2093 | err |= __put_user(from->si_uid, &to->si_uid); | |
2094 | err |= __put_user(from->si_status, &to->si_status); | |
2095 | err |= __put_user(from->si_utime, &to->si_utime); | |
2096 | err |= __put_user(from->si_stime, &to->si_stime); | |
2097 | break; | |
2098 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2099 | case __SI_MESGQ: /* But this is */ | |
2100 | err |= __put_user(from->si_pid, &to->si_pid); | |
2101 | err |= __put_user(from->si_uid, &to->si_uid); | |
2102 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2103 | break; | |
2104 | default: /* this is just in case for now ... */ | |
2105 | err |= __put_user(from->si_pid, &to->si_pid); | |
2106 | err |= __put_user(from->si_uid, &to->si_uid); | |
2107 | break; | |
2108 | } | |
2109 | return err; | |
2110 | } | |
2111 | ||
2112 | #endif | |
2113 | ||
2114 | asmlinkage long | |
2115 | sys_rt_sigtimedwait(const sigset_t __user *uthese, | |
2116 | siginfo_t __user *uinfo, | |
2117 | const struct timespec __user *uts, | |
2118 | size_t sigsetsize) | |
2119 | { | |
2120 | int ret, sig; | |
2121 | sigset_t these; | |
2122 | struct timespec ts; | |
2123 | siginfo_t info; | |
2124 | long timeout = 0; | |
2125 | ||
2126 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2127 | if (sigsetsize != sizeof(sigset_t)) | |
2128 | return -EINVAL; | |
2129 | ||
2130 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2131 | return -EFAULT; | |
2132 | ||
2133 | /* | |
2134 | * Invert the set of allowed signals to get those we | |
2135 | * want to block. | |
2136 | */ | |
2137 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2138 | signotset(&these); | |
2139 | ||
2140 | if (uts) { | |
2141 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2142 | return -EFAULT; | |
2143 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2144 | || ts.tv_sec < 0) | |
2145 | return -EINVAL; | |
2146 | } | |
2147 | ||
2148 | spin_lock_irq(¤t->sighand->siglock); | |
2149 | sig = dequeue_signal(current, &these, &info); | |
2150 | if (!sig) { | |
2151 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2152 | if (uts) | |
2153 | timeout = (timespec_to_jiffies(&ts) | |
2154 | + (ts.tv_sec || ts.tv_nsec)); | |
2155 | ||
2156 | if (timeout) { | |
2157 | /* None ready -- temporarily unblock those we're | |
2158 | * interested while we are sleeping in so that we'll | |
2159 | * be awakened when they arrive. */ | |
2160 | current->real_blocked = current->blocked; | |
2161 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2162 | recalc_sigpending(); | |
2163 | spin_unlock_irq(¤t->sighand->siglock); | |
2164 | ||
75bcc8c5 | 2165 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2166 | |
1da177e4 LT |
2167 | spin_lock_irq(¤t->sighand->siglock); |
2168 | sig = dequeue_signal(current, &these, &info); | |
2169 | current->blocked = current->real_blocked; | |
2170 | siginitset(¤t->real_blocked, 0); | |
2171 | recalc_sigpending(); | |
2172 | } | |
2173 | } | |
2174 | spin_unlock_irq(¤t->sighand->siglock); | |
2175 | ||
2176 | if (sig) { | |
2177 | ret = sig; | |
2178 | if (uinfo) { | |
2179 | if (copy_siginfo_to_user(uinfo, &info)) | |
2180 | ret = -EFAULT; | |
2181 | } | |
2182 | } else { | |
2183 | ret = -EAGAIN; | |
2184 | if (timeout) | |
2185 | ret = -EINTR; | |
2186 | } | |
2187 | ||
2188 | return ret; | |
2189 | } | |
2190 | ||
2191 | asmlinkage long | |
2192 | sys_kill(int pid, int sig) | |
2193 | { | |
2194 | struct siginfo info; | |
2195 | ||
2196 | info.si_signo = sig; | |
2197 | info.si_errno = 0; | |
2198 | info.si_code = SI_USER; | |
2199 | info.si_pid = current->tgid; | |
2200 | info.si_uid = current->uid; | |
2201 | ||
2202 | return kill_something_info(sig, &info, pid); | |
2203 | } | |
2204 | ||
6dd69f10 | 2205 | static int do_tkill(int tgid, int pid, int sig) |
1da177e4 | 2206 | { |
1da177e4 | 2207 | int error; |
6dd69f10 | 2208 | struct siginfo info; |
1da177e4 LT |
2209 | struct task_struct *p; |
2210 | ||
6dd69f10 | 2211 | error = -ESRCH; |
1da177e4 LT |
2212 | info.si_signo = sig; |
2213 | info.si_errno = 0; | |
2214 | info.si_code = SI_TKILL; | |
2215 | info.si_pid = current->tgid; | |
2216 | info.si_uid = current->uid; | |
2217 | ||
2218 | read_lock(&tasklist_lock); | |
2219 | p = find_task_by_pid(pid); | |
6dd69f10 | 2220 | if (p && (tgid <= 0 || p->tgid == tgid)) { |
1da177e4 LT |
2221 | error = check_kill_permission(sig, &info, p); |
2222 | /* | |
2223 | * The null signal is a permissions and process existence | |
2224 | * probe. No signal is actually delivered. | |
2225 | */ | |
2226 | if (!error && sig && p->sighand) { | |
2227 | spin_lock_irq(&p->sighand->siglock); | |
2228 | handle_stop_signal(sig, p); | |
2229 | error = specific_send_sig_info(sig, &info, p); | |
2230 | spin_unlock_irq(&p->sighand->siglock); | |
2231 | } | |
2232 | } | |
2233 | read_unlock(&tasklist_lock); | |
6dd69f10 | 2234 | |
1da177e4 LT |
2235 | return error; |
2236 | } | |
2237 | ||
6dd69f10 VL |
2238 | /** |
2239 | * sys_tgkill - send signal to one specific thread | |
2240 | * @tgid: the thread group ID of the thread | |
2241 | * @pid: the PID of the thread | |
2242 | * @sig: signal to be sent | |
2243 | * | |
2244 | * This syscall also checks the tgid and returns -ESRCH even if the PID | |
2245 | * exists but it's not belonging to the target process anymore. This | |
2246 | * method solves the problem of threads exiting and PIDs getting reused. | |
2247 | */ | |
2248 | asmlinkage long sys_tgkill(int tgid, int pid, int sig) | |
2249 | { | |
2250 | /* This is only valid for single tasks */ | |
2251 | if (pid <= 0 || tgid <= 0) | |
2252 | return -EINVAL; | |
2253 | ||
2254 | return do_tkill(tgid, pid, sig); | |
2255 | } | |
2256 | ||
1da177e4 LT |
2257 | /* |
2258 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2259 | */ | |
2260 | asmlinkage long | |
2261 | sys_tkill(int pid, int sig) | |
2262 | { | |
1da177e4 LT |
2263 | /* This is only valid for single tasks */ |
2264 | if (pid <= 0) | |
2265 | return -EINVAL; | |
2266 | ||
6dd69f10 | 2267 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2268 | } |
2269 | ||
2270 | asmlinkage long | |
2271 | sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) | |
2272 | { | |
2273 | siginfo_t info; | |
2274 | ||
2275 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2276 | return -EFAULT; | |
2277 | ||
2278 | /* Not even root can pretend to send signals from the kernel. | |
2279 | Nor can they impersonate a kill(), which adds source info. */ | |
2280 | if (info.si_code >= 0) | |
2281 | return -EPERM; | |
2282 | info.si_signo = sig; | |
2283 | ||
2284 | /* POSIX.1b doesn't mention process groups. */ | |
2285 | return kill_proc_info(sig, &info, pid); | |
2286 | } | |
2287 | ||
88531f72 | 2288 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 LT |
2289 | { |
2290 | struct k_sigaction *k; | |
71fabd5e | 2291 | sigset_t mask; |
1da177e4 | 2292 | |
7ed20e1a | 2293 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2294 | return -EINVAL; |
2295 | ||
2296 | k = ¤t->sighand->action[sig-1]; | |
2297 | ||
2298 | spin_lock_irq(¤t->sighand->siglock); | |
2299 | if (signal_pending(current)) { | |
2300 | /* | |
2301 | * If there might be a fatal signal pending on multiple | |
2302 | * threads, make sure we take it before changing the action. | |
2303 | */ | |
2304 | spin_unlock_irq(¤t->sighand->siglock); | |
2305 | return -ERESTARTNOINTR; | |
2306 | } | |
2307 | ||
2308 | if (oact) | |
2309 | *oact = *k; | |
2310 | ||
2311 | if (act) { | |
9ac95f2f ON |
2312 | sigdelsetmask(&act->sa.sa_mask, |
2313 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2314 | *k = *act; |
1da177e4 LT |
2315 | /* |
2316 | * POSIX 3.3.1.3: | |
2317 | * "Setting a signal action to SIG_IGN for a signal that is | |
2318 | * pending shall cause the pending signal to be discarded, | |
2319 | * whether or not it is blocked." | |
2320 | * | |
2321 | * "Setting a signal action to SIG_DFL for a signal that is | |
2322 | * pending and whose default action is to ignore the signal | |
2323 | * (for example, SIGCHLD), shall cause the pending signal to | |
2324 | * be discarded, whether or not it is blocked" | |
2325 | */ | |
2326 | if (act->sa.sa_handler == SIG_IGN || | |
88531f72 | 2327 | (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) { |
1da177e4 | 2328 | struct task_struct *t = current; |
71fabd5e GA |
2329 | sigemptyset(&mask); |
2330 | sigaddset(&mask, sig); | |
2331 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2332 | do { |
71fabd5e | 2333 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2334 | recalc_sigpending_tsk(t); |
2335 | t = next_thread(t); | |
2336 | } while (t != current); | |
1da177e4 | 2337 | } |
1da177e4 LT |
2338 | } |
2339 | ||
2340 | spin_unlock_irq(¤t->sighand->siglock); | |
2341 | return 0; | |
2342 | } | |
2343 | ||
2344 | int | |
2345 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2346 | { | |
2347 | stack_t oss; | |
2348 | int error; | |
2349 | ||
2350 | if (uoss) { | |
2351 | oss.ss_sp = (void __user *) current->sas_ss_sp; | |
2352 | oss.ss_size = current->sas_ss_size; | |
2353 | oss.ss_flags = sas_ss_flags(sp); | |
2354 | } | |
2355 | ||
2356 | if (uss) { | |
2357 | void __user *ss_sp; | |
2358 | size_t ss_size; | |
2359 | int ss_flags; | |
2360 | ||
2361 | error = -EFAULT; | |
2362 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss)) | |
2363 | || __get_user(ss_sp, &uss->ss_sp) | |
2364 | || __get_user(ss_flags, &uss->ss_flags) | |
2365 | || __get_user(ss_size, &uss->ss_size)) | |
2366 | goto out; | |
2367 | ||
2368 | error = -EPERM; | |
2369 | if (on_sig_stack(sp)) | |
2370 | goto out; | |
2371 | ||
2372 | error = -EINVAL; | |
2373 | /* | |
2374 | * | |
2375 | * Note - this code used to test ss_flags incorrectly | |
2376 | * old code may have been written using ss_flags==0 | |
2377 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2378 | * way that worked) - this fix preserves that older | |
2379 | * mechanism | |
2380 | */ | |
2381 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2382 | goto out; | |
2383 | ||
2384 | if (ss_flags == SS_DISABLE) { | |
2385 | ss_size = 0; | |
2386 | ss_sp = NULL; | |
2387 | } else { | |
2388 | error = -ENOMEM; | |
2389 | if (ss_size < MINSIGSTKSZ) | |
2390 | goto out; | |
2391 | } | |
2392 | ||
2393 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2394 | current->sas_ss_size = ss_size; | |
2395 | } | |
2396 | ||
2397 | if (uoss) { | |
2398 | error = -EFAULT; | |
2399 | if (copy_to_user(uoss, &oss, sizeof(oss))) | |
2400 | goto out; | |
2401 | } | |
2402 | ||
2403 | error = 0; | |
2404 | out: | |
2405 | return error; | |
2406 | } | |
2407 | ||
2408 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2409 | ||
2410 | asmlinkage long | |
2411 | sys_sigpending(old_sigset_t __user *set) | |
2412 | { | |
2413 | return do_sigpending(set, sizeof(*set)); | |
2414 | } | |
2415 | ||
2416 | #endif | |
2417 | ||
2418 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2419 | /* Some platforms have their own version with special arguments others | |
2420 | support only sys_rt_sigprocmask. */ | |
2421 | ||
2422 | asmlinkage long | |
2423 | sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset) | |
2424 | { | |
2425 | int error; | |
2426 | old_sigset_t old_set, new_set; | |
2427 | ||
2428 | if (set) { | |
2429 | error = -EFAULT; | |
2430 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2431 | goto out; | |
2432 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2433 | ||
2434 | spin_lock_irq(¤t->sighand->siglock); | |
2435 | old_set = current->blocked.sig[0]; | |
2436 | ||
2437 | error = 0; | |
2438 | switch (how) { | |
2439 | default: | |
2440 | error = -EINVAL; | |
2441 | break; | |
2442 | case SIG_BLOCK: | |
2443 | sigaddsetmask(¤t->blocked, new_set); | |
2444 | break; | |
2445 | case SIG_UNBLOCK: | |
2446 | sigdelsetmask(¤t->blocked, new_set); | |
2447 | break; | |
2448 | case SIG_SETMASK: | |
2449 | current->blocked.sig[0] = new_set; | |
2450 | break; | |
2451 | } | |
2452 | ||
2453 | recalc_sigpending(); | |
2454 | spin_unlock_irq(¤t->sighand->siglock); | |
2455 | if (error) | |
2456 | goto out; | |
2457 | if (oset) | |
2458 | goto set_old; | |
2459 | } else if (oset) { | |
2460 | old_set = current->blocked.sig[0]; | |
2461 | set_old: | |
2462 | error = -EFAULT; | |
2463 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2464 | goto out; | |
2465 | } | |
2466 | error = 0; | |
2467 | out: | |
2468 | return error; | |
2469 | } | |
2470 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2471 | ||
2472 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
2473 | asmlinkage long | |
2474 | sys_rt_sigaction(int sig, | |
2475 | const struct sigaction __user *act, | |
2476 | struct sigaction __user *oact, | |
2477 | size_t sigsetsize) | |
2478 | { | |
2479 | struct k_sigaction new_sa, old_sa; | |
2480 | int ret = -EINVAL; | |
2481 | ||
2482 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2483 | if (sigsetsize != sizeof(sigset_t)) | |
2484 | goto out; | |
2485 | ||
2486 | if (act) { | |
2487 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2488 | return -EFAULT; | |
2489 | } | |
2490 | ||
2491 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2492 | ||
2493 | if (!ret && oact) { | |
2494 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2495 | return -EFAULT; | |
2496 | } | |
2497 | out: | |
2498 | return ret; | |
2499 | } | |
2500 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2501 | ||
2502 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2503 | ||
2504 | /* | |
2505 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2506 | */ | |
2507 | asmlinkage long | |
2508 | sys_sgetmask(void) | |
2509 | { | |
2510 | /* SMP safe */ | |
2511 | return current->blocked.sig[0]; | |
2512 | } | |
2513 | ||
2514 | asmlinkage long | |
2515 | sys_ssetmask(int newmask) | |
2516 | { | |
2517 | int old; | |
2518 | ||
2519 | spin_lock_irq(¤t->sighand->siglock); | |
2520 | old = current->blocked.sig[0]; | |
2521 | ||
2522 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2523 | sigmask(SIGSTOP))); | |
2524 | recalc_sigpending(); | |
2525 | spin_unlock_irq(¤t->sighand->siglock); | |
2526 | ||
2527 | return old; | |
2528 | } | |
2529 | #endif /* __ARCH_WANT_SGETMASK */ | |
2530 | ||
2531 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2532 | /* | |
2533 | * For backwards compatibility. Functionality superseded by sigaction. | |
2534 | */ | |
2535 | asmlinkage unsigned long | |
2536 | sys_signal(int sig, __sighandler_t handler) | |
2537 | { | |
2538 | struct k_sigaction new_sa, old_sa; | |
2539 | int ret; | |
2540 | ||
2541 | new_sa.sa.sa_handler = handler; | |
2542 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2543 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2544 | |
2545 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2546 | ||
2547 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2548 | } | |
2549 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2550 | ||
2551 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2552 | ||
2553 | asmlinkage long | |
2554 | sys_pause(void) | |
2555 | { | |
2556 | current->state = TASK_INTERRUPTIBLE; | |
2557 | schedule(); | |
2558 | return -ERESTARTNOHAND; | |
2559 | } | |
2560 | ||
2561 | #endif | |
2562 | ||
150256d8 DW |
2563 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
2564 | asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize) | |
2565 | { | |
2566 | sigset_t newset; | |
2567 | ||
2568 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2569 | if (sigsetsize != sizeof(sigset_t)) | |
2570 | return -EINVAL; | |
2571 | ||
2572 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2573 | return -EFAULT; | |
2574 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2575 | ||
2576 | spin_lock_irq(¤t->sighand->siglock); | |
2577 | current->saved_sigmask = current->blocked; | |
2578 | current->blocked = newset; | |
2579 | recalc_sigpending(); | |
2580 | spin_unlock_irq(¤t->sighand->siglock); | |
2581 | ||
2582 | current->state = TASK_INTERRUPTIBLE; | |
2583 | schedule(); | |
2584 | set_thread_flag(TIF_RESTORE_SIGMASK); | |
2585 | return -ERESTARTNOHAND; | |
2586 | } | |
2587 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2588 | ||
1da177e4 LT |
2589 | void __init signals_init(void) |
2590 | { | |
2591 | sigqueue_cachep = | |
2592 | kmem_cache_create("sigqueue", | |
2593 | sizeof(struct sigqueue), | |
2594 | __alignof__(struct sigqueue), | |
2595 | SLAB_PANIC, NULL, NULL); | |
2596 | } |