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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> | |
25 | #include <linux/posix-timers.h> | |
7ed20e1a | 26 | #include <linux/signal.h> |
c2f0c7c3 | 27 | #include <linux/audit.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 | ||
149 | #define sig_user_defined(t, signr) \ | |
150 | (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) && \ | |
151 | ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN)) | |
152 | ||
153 | #define sig_fatal(t, signr) \ | |
154 | (!T(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \ | |
155 | (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL) | |
156 | ||
157 | static int sig_ignored(struct task_struct *t, int sig) | |
158 | { | |
159 | void __user * handler; | |
160 | ||
161 | /* | |
162 | * Tracers always want to know about signals.. | |
163 | */ | |
164 | if (t->ptrace & PT_PTRACED) | |
165 | return 0; | |
166 | ||
167 | /* | |
168 | * Blocked signals are never ignored, since the | |
169 | * signal handler may change by the time it is | |
170 | * unblocked. | |
171 | */ | |
172 | if (sigismember(&t->blocked, sig)) | |
173 | return 0; | |
174 | ||
175 | /* Is it explicitly or implicitly ignored? */ | |
176 | handler = t->sighand->action[sig-1].sa.sa_handler; | |
177 | return handler == SIG_IGN || | |
178 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
179 | } | |
180 | ||
181 | /* | |
182 | * Re-calculate pending state from the set of locally pending | |
183 | * signals, globally pending signals, and blocked signals. | |
184 | */ | |
185 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
186 | { | |
187 | unsigned long ready; | |
188 | long i; | |
189 | ||
190 | switch (_NSIG_WORDS) { | |
191 | default: | |
192 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
193 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
194 | break; | |
195 | ||
196 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
197 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
198 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
199 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
200 | break; | |
201 | ||
202 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
203 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
204 | break; | |
205 | ||
206 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
207 | } | |
208 | return ready != 0; | |
209 | } | |
210 | ||
211 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
212 | ||
213 | fastcall void recalc_sigpending_tsk(struct task_struct *t) | |
214 | { | |
215 | if (t->signal->group_stop_count > 0 || | |
3e1d1d28 | 216 | (freezing(t)) || |
1da177e4 LT |
217 | PENDING(&t->pending, &t->blocked) || |
218 | PENDING(&t->signal->shared_pending, &t->blocked)) | |
219 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
220 | else | |
221 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
222 | } | |
223 | ||
224 | void recalc_sigpending(void) | |
225 | { | |
226 | recalc_sigpending_tsk(current); | |
227 | } | |
228 | ||
229 | /* Given the mask, find the first available signal that should be serviced. */ | |
230 | ||
231 | static int | |
232 | next_signal(struct sigpending *pending, sigset_t *mask) | |
233 | { | |
234 | unsigned long i, *s, *m, x; | |
235 | int sig = 0; | |
236 | ||
237 | s = pending->signal.sig; | |
238 | m = mask->sig; | |
239 | switch (_NSIG_WORDS) { | |
240 | default: | |
241 | for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m) | |
242 | if ((x = *s &~ *m) != 0) { | |
243 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
244 | break; | |
245 | } | |
246 | break; | |
247 | ||
248 | case 2: if ((x = s[0] &~ m[0]) != 0) | |
249 | sig = 1; | |
250 | else if ((x = s[1] &~ m[1]) != 0) | |
251 | sig = _NSIG_BPW + 1; | |
252 | else | |
253 | break; | |
254 | sig += ffz(~x); | |
255 | break; | |
256 | ||
257 | case 1: if ((x = *s &~ *m) != 0) | |
258 | sig = ffz(~x) + 1; | |
259 | break; | |
260 | } | |
261 | ||
262 | return sig; | |
263 | } | |
264 | ||
dd0fc66f | 265 | static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, |
1da177e4 LT |
266 | int override_rlimit) |
267 | { | |
268 | struct sigqueue *q = NULL; | |
269 | ||
270 | atomic_inc(&t->user->sigpending); | |
271 | if (override_rlimit || | |
272 | atomic_read(&t->user->sigpending) <= | |
273 | t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) | |
274 | q = kmem_cache_alloc(sigqueue_cachep, flags); | |
275 | if (unlikely(q == NULL)) { | |
276 | atomic_dec(&t->user->sigpending); | |
277 | } else { | |
278 | INIT_LIST_HEAD(&q->list); | |
279 | q->flags = 0; | |
280 | q->lock = NULL; | |
281 | q->user = get_uid(t->user); | |
282 | } | |
283 | return(q); | |
284 | } | |
285 | ||
286 | static inline void __sigqueue_free(struct sigqueue *q) | |
287 | { | |
288 | if (q->flags & SIGQUEUE_PREALLOC) | |
289 | return; | |
290 | atomic_dec(&q->user->sigpending); | |
291 | free_uid(q->user); | |
292 | kmem_cache_free(sigqueue_cachep, q); | |
293 | } | |
294 | ||
295 | static void flush_sigqueue(struct sigpending *queue) | |
296 | { | |
297 | struct sigqueue *q; | |
298 | ||
299 | sigemptyset(&queue->signal); | |
300 | while (!list_empty(&queue->list)) { | |
301 | q = list_entry(queue->list.next, struct sigqueue , list); | |
302 | list_del_init(&q->list); | |
303 | __sigqueue_free(q); | |
304 | } | |
305 | } | |
306 | ||
307 | /* | |
308 | * Flush all pending signals for a task. | |
309 | */ | |
310 | ||
311 | void | |
312 | flush_signals(struct task_struct *t) | |
313 | { | |
314 | unsigned long flags; | |
315 | ||
316 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
317 | clear_tsk_thread_flag(t,TIF_SIGPENDING); | |
318 | flush_sigqueue(&t->pending); | |
319 | flush_sigqueue(&t->signal->shared_pending); | |
320 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
321 | } | |
322 | ||
323 | /* | |
324 | * This function expects the tasklist_lock write-locked. | |
325 | */ | |
326 | void __exit_sighand(struct task_struct *tsk) | |
327 | { | |
328 | struct sighand_struct * sighand = tsk->sighand; | |
329 | ||
330 | /* Ok, we're done with the signal handlers */ | |
331 | tsk->sighand = NULL; | |
332 | if (atomic_dec_and_test(&sighand->count)) | |
333 | kmem_cache_free(sighand_cachep, sighand); | |
334 | } | |
335 | ||
336 | void exit_sighand(struct task_struct *tsk) | |
337 | { | |
338 | write_lock_irq(&tasklist_lock); | |
339 | __exit_sighand(tsk); | |
340 | write_unlock_irq(&tasklist_lock); | |
341 | } | |
342 | ||
343 | /* | |
344 | * This function expects the tasklist_lock write-locked. | |
345 | */ | |
346 | void __exit_signal(struct task_struct *tsk) | |
347 | { | |
348 | struct signal_struct * sig = tsk->signal; | |
349 | struct sighand_struct * sighand = tsk->sighand; | |
350 | ||
351 | if (!sig) | |
352 | BUG(); | |
353 | if (!atomic_read(&sig->count)) | |
354 | BUG(); | |
355 | spin_lock(&sighand->siglock); | |
356 | posix_cpu_timers_exit(tsk); | |
357 | if (atomic_dec_and_test(&sig->count)) { | |
358 | posix_cpu_timers_exit_group(tsk); | |
359 | if (tsk == sig->curr_target) | |
360 | sig->curr_target = next_thread(tsk); | |
361 | tsk->signal = NULL; | |
362 | spin_unlock(&sighand->siglock); | |
363 | flush_sigqueue(&sig->shared_pending); | |
364 | } else { | |
365 | /* | |
366 | * If there is any task waiting for the group exit | |
367 | * then notify it: | |
368 | */ | |
369 | if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) { | |
370 | wake_up_process(sig->group_exit_task); | |
371 | sig->group_exit_task = NULL; | |
372 | } | |
373 | if (tsk == sig->curr_target) | |
374 | sig->curr_target = next_thread(tsk); | |
375 | tsk->signal = NULL; | |
376 | /* | |
377 | * Accumulate here the counters for all threads but the | |
378 | * group leader as they die, so they can be added into | |
379 | * the process-wide totals when those are taken. | |
380 | * The group leader stays around as a zombie as long | |
381 | * as there are other threads. When it gets reaped, | |
382 | * the exit.c code will add its counts into these totals. | |
383 | * We won't ever get here for the group leader, since it | |
384 | * will have been the last reference on the signal_struct. | |
385 | */ | |
386 | sig->utime = cputime_add(sig->utime, tsk->utime); | |
387 | sig->stime = cputime_add(sig->stime, tsk->stime); | |
388 | sig->min_flt += tsk->min_flt; | |
389 | sig->maj_flt += tsk->maj_flt; | |
390 | sig->nvcsw += tsk->nvcsw; | |
391 | sig->nivcsw += tsk->nivcsw; | |
392 | sig->sched_time += tsk->sched_time; | |
393 | spin_unlock(&sighand->siglock); | |
394 | sig = NULL; /* Marker for below. */ | |
395 | } | |
396 | clear_tsk_thread_flag(tsk,TIF_SIGPENDING); | |
397 | flush_sigqueue(&tsk->pending); | |
398 | if (sig) { | |
399 | /* | |
25f407f0 | 400 | * We are cleaning up the signal_struct here. |
1da177e4 | 401 | */ |
1da177e4 LT |
402 | exit_thread_group_keys(sig); |
403 | kmem_cache_free(signal_cachep, sig); | |
404 | } | |
405 | } | |
406 | ||
407 | void exit_signal(struct task_struct *tsk) | |
408 | { | |
8d027de5 ON |
409 | atomic_dec(&tsk->signal->live); |
410 | ||
1da177e4 LT |
411 | write_lock_irq(&tasklist_lock); |
412 | __exit_signal(tsk); | |
413 | write_unlock_irq(&tasklist_lock); | |
414 | } | |
415 | ||
416 | /* | |
417 | * Flush all handlers for a task. | |
418 | */ | |
419 | ||
420 | void | |
421 | flush_signal_handlers(struct task_struct *t, int force_default) | |
422 | { | |
423 | int i; | |
424 | struct k_sigaction *ka = &t->sighand->action[0]; | |
425 | for (i = _NSIG ; i != 0 ; i--) { | |
426 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
427 | ka->sa.sa_handler = SIG_DFL; | |
428 | ka->sa.sa_flags = 0; | |
429 | sigemptyset(&ka->sa.sa_mask); | |
430 | ka++; | |
431 | } | |
432 | } | |
433 | ||
434 | ||
435 | /* Notify the system that a driver wants to block all signals for this | |
436 | * process, and wants to be notified if any signals at all were to be | |
437 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
438 | * signal will be acted upon after all. If the notifier routine returns 0, | |
439 | * then then signal will be blocked. Only one block per process is | |
440 | * allowed. priv is a pointer to private data that the notifier routine | |
441 | * can use to determine if the signal should be blocked or not. */ | |
442 | ||
443 | void | |
444 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
445 | { | |
446 | unsigned long flags; | |
447 | ||
448 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
449 | current->notifier_mask = mask; | |
450 | current->notifier_data = priv; | |
451 | current->notifier = notifier; | |
452 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
453 | } | |
454 | ||
455 | /* Notify the system that blocking has ended. */ | |
456 | ||
457 | void | |
458 | unblock_all_signals(void) | |
459 | { | |
460 | unsigned long flags; | |
461 | ||
462 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
463 | current->notifier = NULL; | |
464 | current->notifier_data = NULL; | |
465 | recalc_sigpending(); | |
466 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
467 | } | |
468 | ||
469 | static inline int collect_signal(int sig, struct sigpending *list, siginfo_t *info) | |
470 | { | |
471 | struct sigqueue *q, *first = NULL; | |
472 | int still_pending = 0; | |
473 | ||
474 | if (unlikely(!sigismember(&list->signal, sig))) | |
475 | return 0; | |
476 | ||
477 | /* | |
478 | * Collect the siginfo appropriate to this signal. Check if | |
479 | * there is another siginfo for the same signal. | |
480 | */ | |
481 | list_for_each_entry(q, &list->list, list) { | |
482 | if (q->info.si_signo == sig) { | |
483 | if (first) { | |
484 | still_pending = 1; | |
485 | break; | |
486 | } | |
487 | first = q; | |
488 | } | |
489 | } | |
490 | if (first) { | |
491 | list_del_init(&first->list); | |
492 | copy_siginfo(info, &first->info); | |
493 | __sigqueue_free(first); | |
494 | if (!still_pending) | |
495 | sigdelset(&list->signal, sig); | |
496 | } else { | |
497 | ||
498 | /* Ok, it wasn't in the queue. This must be | |
499 | a fast-pathed signal or we must have been | |
500 | out of queue space. So zero out the info. | |
501 | */ | |
502 | sigdelset(&list->signal, sig); | |
503 | info->si_signo = sig; | |
504 | info->si_errno = 0; | |
505 | info->si_code = 0; | |
506 | info->si_pid = 0; | |
507 | info->si_uid = 0; | |
508 | } | |
509 | return 1; | |
510 | } | |
511 | ||
512 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
513 | siginfo_t *info) | |
514 | { | |
515 | int sig = 0; | |
516 | ||
c33880aa KK |
517 | /* SIGKILL must have priority, otherwise it is quite easy |
518 | * to create an unkillable process, sending sig < SIGKILL | |
519 | * to self */ | |
520 | if (unlikely(sigismember(&pending->signal, SIGKILL))) { | |
521 | if (!sigismember(mask, SIGKILL)) | |
522 | sig = SIGKILL; | |
523 | } | |
524 | ||
525 | if (likely(!sig)) | |
526 | sig = next_signal(pending, mask); | |
1da177e4 LT |
527 | if (sig) { |
528 | if (current->notifier) { | |
529 | if (sigismember(current->notifier_mask, sig)) { | |
530 | if (!(current->notifier)(current->notifier_data)) { | |
531 | clear_thread_flag(TIF_SIGPENDING); | |
532 | return 0; | |
533 | } | |
534 | } | |
535 | } | |
536 | ||
537 | if (!collect_signal(sig, pending, info)) | |
538 | sig = 0; | |
539 | ||
540 | } | |
541 | recalc_sigpending(); | |
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 | { | |
554 | int signr = __dequeue_signal(&tsk->pending, mask, info); | |
555 | if (!signr) | |
556 | signr = __dequeue_signal(&tsk->signal->shared_pending, | |
557 | mask, info); | |
558 | if (signr && unlikely(sig_kernel_stop(signr))) { | |
559 | /* | |
560 | * Set a marker that we have dequeued a stop signal. Our | |
561 | * caller might release the siglock and then the pending | |
562 | * stop signal it is about to process is no longer in the | |
563 | * pending bitmasks, but must still be cleared by a SIGCONT | |
564 | * (and overruled by a SIGKILL). So those cases clear this | |
565 | * shared flag after we've set it. Note that this flag may | |
566 | * remain set after the signal we return is ignored or | |
567 | * handled. That doesn't matter because its only purpose | |
568 | * is to alert stop-signal processing code when another | |
569 | * processor has come along and cleared the flag. | |
570 | */ | |
788e05a6 ON |
571 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) |
572 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; | |
1da177e4 LT |
573 | } |
574 | if ( signr && | |
575 | ((info->si_code & __SI_MASK) == __SI_TIMER) && | |
576 | info->si_sys_private){ | |
577 | /* | |
578 | * Release the siglock to ensure proper locking order | |
579 | * of timer locks outside of siglocks. Note, we leave | |
580 | * irqs disabled here, since the posix-timers code is | |
581 | * about to disable them again anyway. | |
582 | */ | |
583 | spin_unlock(&tsk->sighand->siglock); | |
584 | do_schedule_next_timer(info); | |
585 | spin_lock(&tsk->sighand->siglock); | |
586 | } | |
587 | return signr; | |
588 | } | |
589 | ||
590 | /* | |
591 | * Tell a process that it has a new active signal.. | |
592 | * | |
593 | * NOTE! we rely on the previous spin_lock to | |
594 | * lock interrupts for us! We can only be called with | |
595 | * "siglock" held, and the local interrupt must | |
596 | * have been disabled when that got acquired! | |
597 | * | |
598 | * No need to set need_resched since signal event passing | |
599 | * goes through ->blocked | |
600 | */ | |
601 | void signal_wake_up(struct task_struct *t, int resume) | |
602 | { | |
603 | unsigned int mask; | |
604 | ||
605 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
606 | ||
607 | /* | |
608 | * For SIGKILL, we want to wake it up in the stopped/traced case. | |
609 | * We don't check t->state here because there is a race with it | |
610 | * executing another processor and just now entering stopped state. | |
611 | * By using wake_up_state, we ensure the process will wake up and | |
612 | * handle its death signal. | |
613 | */ | |
614 | mask = TASK_INTERRUPTIBLE; | |
615 | if (resume) | |
616 | mask |= TASK_STOPPED | TASK_TRACED; | |
617 | if (!wake_up_state(t, mask)) | |
618 | kick_process(t); | |
619 | } | |
620 | ||
621 | /* | |
622 | * Remove signals in mask from the pending set and queue. | |
623 | * Returns 1 if any signals were found. | |
624 | * | |
625 | * All callers must be holding the siglock. | |
626 | */ | |
627 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
628 | { | |
629 | struct sigqueue *q, *n; | |
630 | ||
631 | if (!sigtestsetmask(&s->signal, mask)) | |
632 | return 0; | |
633 | ||
634 | sigdelsetmask(&s->signal, mask); | |
635 | list_for_each_entry_safe(q, n, &s->list, list) { | |
636 | if (q->info.si_signo < SIGRTMIN && | |
637 | (mask & sigmask(q->info.si_signo))) { | |
638 | list_del_init(&q->list); | |
639 | __sigqueue_free(q); | |
640 | } | |
641 | } | |
642 | return 1; | |
643 | } | |
644 | ||
645 | /* | |
646 | * Bad permissions for sending the signal | |
647 | */ | |
648 | static int check_kill_permission(int sig, struct siginfo *info, | |
649 | struct task_struct *t) | |
650 | { | |
651 | int error = -EINVAL; | |
7ed20e1a | 652 | if (!valid_signal(sig)) |
1da177e4 LT |
653 | return error; |
654 | error = -EPERM; | |
655 | if ((!info || ((unsigned long)info != 1 && | |
656 | (unsigned long)info != 2 && SI_FROMUSER(info))) | |
657 | && ((sig != SIGCONT) || | |
658 | (current->signal->session != t->signal->session)) | |
659 | && (current->euid ^ t->suid) && (current->euid ^ t->uid) | |
660 | && (current->uid ^ t->suid) && (current->uid ^ t->uid) | |
661 | && !capable(CAP_KILL)) | |
662 | return error; | |
c2f0c7c3 SG |
663 | |
664 | error = security_task_kill(t, info, sig); | |
665 | if (!error) | |
666 | audit_signal_info(sig, t); /* Let audit system see the signal */ | |
667 | return error; | |
1da177e4 LT |
668 | } |
669 | ||
670 | /* forward decl */ | |
671 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
bc505a47 | 672 | int to_self, |
1da177e4 LT |
673 | int why); |
674 | ||
675 | /* | |
676 | * Handle magic process-wide effects of stop/continue signals. | |
677 | * Unlike the signal actions, these happen immediately at signal-generation | |
678 | * time regardless of blocking, ignoring, or handling. This does the | |
679 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
680 | * signals. The process stop is done as a signal action for SIG_DFL. | |
681 | */ | |
682 | static void handle_stop_signal(int sig, struct task_struct *p) | |
683 | { | |
684 | struct task_struct *t; | |
685 | ||
dd12f48d | 686 | if (p->signal->flags & SIGNAL_GROUP_EXIT) |
1da177e4 LT |
687 | /* |
688 | * The process is in the middle of dying already. | |
689 | */ | |
690 | return; | |
691 | ||
692 | if (sig_kernel_stop(sig)) { | |
693 | /* | |
694 | * This is a stop signal. Remove SIGCONT from all queues. | |
695 | */ | |
696 | rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending); | |
697 | t = p; | |
698 | do { | |
699 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
700 | t = next_thread(t); | |
701 | } while (t != p); | |
702 | } else if (sig == SIGCONT) { | |
703 | /* | |
704 | * Remove all stop signals from all queues, | |
705 | * and wake all threads. | |
706 | */ | |
707 | if (unlikely(p->signal->group_stop_count > 0)) { | |
708 | /* | |
709 | * There was a group stop in progress. We'll | |
710 | * pretend it finished before we got here. We are | |
711 | * obliged to report it to the parent: if the | |
712 | * SIGSTOP happened "after" this SIGCONT, then it | |
713 | * would have cleared this pending SIGCONT. If it | |
714 | * happened "before" this SIGCONT, then the parent | |
715 | * got the SIGCHLD about the stop finishing before | |
716 | * the continue happened. We do the notification | |
717 | * now, and it's as if the stop had finished and | |
718 | * the SIGCHLD was pending on entry to this kill. | |
719 | */ | |
720 | p->signal->group_stop_count = 0; | |
721 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
722 | spin_unlock(&p->sighand->siglock); | |
bc505a47 | 723 | do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_STOPPED); |
1da177e4 LT |
724 | spin_lock(&p->sighand->siglock); |
725 | } | |
726 | rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); | |
727 | t = p; | |
728 | do { | |
729 | unsigned int state; | |
730 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
731 | ||
732 | /* | |
733 | * If there is a handler for SIGCONT, we must make | |
734 | * sure that no thread returns to user mode before | |
735 | * we post the signal, in case it was the only | |
736 | * thread eligible to run the signal handler--then | |
737 | * it must not do anything between resuming and | |
738 | * running the handler. With the TIF_SIGPENDING | |
739 | * flag set, the thread will pause and acquire the | |
740 | * siglock that we hold now and until we've queued | |
741 | * the pending signal. | |
742 | * | |
743 | * Wake up the stopped thread _after_ setting | |
744 | * TIF_SIGPENDING | |
745 | */ | |
746 | state = TASK_STOPPED; | |
747 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { | |
748 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
749 | state |= TASK_INTERRUPTIBLE; | |
750 | } | |
751 | wake_up_state(t, state); | |
752 | ||
753 | t = next_thread(t); | |
754 | } while (t != p); | |
755 | ||
756 | if (p->signal->flags & SIGNAL_STOP_STOPPED) { | |
757 | /* | |
758 | * We were in fact stopped, and are now continued. | |
759 | * Notify the parent with CLD_CONTINUED. | |
760 | */ | |
761 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
762 | p->signal->group_exit_code = 0; | |
763 | spin_unlock(&p->sighand->siglock); | |
bc505a47 | 764 | do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_CONTINUED); |
1da177e4 LT |
765 | spin_lock(&p->sighand->siglock); |
766 | } else { | |
767 | /* | |
768 | * We are not stopped, but there could be a stop | |
769 | * signal in the middle of being processed after | |
770 | * being removed from the queue. Clear that too. | |
771 | */ | |
772 | p->signal->flags = 0; | |
773 | } | |
774 | } else if (sig == SIGKILL) { | |
775 | /* | |
776 | * Make sure that any pending stop signal already dequeued | |
777 | * is undone by the wakeup for SIGKILL. | |
778 | */ | |
779 | p->signal->flags = 0; | |
780 | } | |
781 | } | |
782 | ||
783 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, | |
784 | struct sigpending *signals) | |
785 | { | |
786 | struct sigqueue * q = NULL; | |
787 | int ret = 0; | |
788 | ||
789 | /* | |
790 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
791 | * or SIGKILL. | |
792 | */ | |
793 | if ((unsigned long)info == 2) | |
794 | goto out_set; | |
795 | ||
796 | /* Real-time signals must be queued if sent by sigqueue, or | |
797 | some other real-time mechanism. It is implementation | |
798 | defined whether kill() does so. We attempt to do so, on | |
799 | the principle of least surprise, but since kill is not | |
800 | allowed to fail with EAGAIN when low on memory we just | |
801 | make sure at least one signal gets delivered and don't | |
802 | pass on the info struct. */ | |
803 | ||
804 | q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN && | |
805 | ((unsigned long) info < 2 || | |
806 | info->si_code >= 0))); | |
807 | if (q) { | |
808 | list_add_tail(&q->list, &signals->list); | |
809 | switch ((unsigned long) info) { | |
810 | case 0: | |
811 | q->info.si_signo = sig; | |
812 | q->info.si_errno = 0; | |
813 | q->info.si_code = SI_USER; | |
814 | q->info.si_pid = current->pid; | |
815 | q->info.si_uid = current->uid; | |
816 | break; | |
817 | case 1: | |
818 | q->info.si_signo = sig; | |
819 | q->info.si_errno = 0; | |
820 | q->info.si_code = SI_KERNEL; | |
821 | q->info.si_pid = 0; | |
822 | q->info.si_uid = 0; | |
823 | break; | |
824 | default: | |
825 | copy_siginfo(&q->info, info); | |
826 | break; | |
827 | } | |
828 | } else { | |
829 | if (sig >= SIGRTMIN && info && (unsigned long)info != 1 | |
830 | && info->si_code != SI_USER) | |
831 | /* | |
832 | * Queue overflow, abort. We may abort if the signal was rt | |
833 | * and sent by user using something other than kill(). | |
834 | */ | |
835 | return -EAGAIN; | |
836 | if (((unsigned long)info > 1) && (info->si_code == SI_TIMER)) | |
837 | /* | |
838 | * Set up a return to indicate that we dropped | |
839 | * the signal. | |
840 | */ | |
841 | ret = info->si_sys_private; | |
842 | } | |
843 | ||
844 | out_set: | |
845 | sigaddset(&signals->signal, sig); | |
846 | return ret; | |
847 | } | |
848 | ||
849 | #define LEGACY_QUEUE(sigptr, sig) \ | |
850 | (((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig))) | |
851 | ||
852 | ||
853 | static int | |
854 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
855 | { | |
856 | int ret = 0; | |
857 | ||
858 | if (!irqs_disabled()) | |
859 | BUG(); | |
860 | assert_spin_locked(&t->sighand->siglock); | |
861 | ||
862 | if (((unsigned long)info > 2) && (info->si_code == SI_TIMER)) | |
863 | /* | |
864 | * Set up a return to indicate that we dropped the signal. | |
865 | */ | |
866 | ret = info->si_sys_private; | |
867 | ||
868 | /* Short-circuit ignored signals. */ | |
869 | if (sig_ignored(t, sig)) | |
870 | goto out; | |
871 | ||
872 | /* Support queueing exactly one non-rt signal, so that we | |
873 | can get more detailed information about the cause of | |
874 | the signal. */ | |
875 | if (LEGACY_QUEUE(&t->pending, sig)) | |
876 | goto out; | |
877 | ||
878 | ret = send_signal(sig, info, t, &t->pending); | |
879 | if (!ret && !sigismember(&t->blocked, sig)) | |
880 | signal_wake_up(t, sig == SIGKILL); | |
881 | out: | |
882 | return ret; | |
883 | } | |
884 | ||
885 | /* | |
886 | * Force a signal that the process can't ignore: if necessary | |
887 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
888 | */ | |
889 | ||
890 | int | |
891 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
892 | { | |
893 | unsigned long int flags; | |
894 | int ret; | |
895 | ||
896 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
897 | if (sigismember(&t->blocked, sig) || t->sighand->action[sig-1].sa.sa_handler == SIG_IGN) { | |
898 | t->sighand->action[sig-1].sa.sa_handler = SIG_DFL; | |
899 | sigdelset(&t->blocked, sig); | |
900 | recalc_sigpending_tsk(t); | |
901 | } | |
902 | ret = specific_send_sig_info(sig, info, t); | |
903 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
904 | ||
905 | return ret; | |
906 | } | |
907 | ||
908 | void | |
909 | force_sig_specific(int sig, struct task_struct *t) | |
910 | { | |
911 | unsigned long int flags; | |
912 | ||
913 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
914 | if (t->sighand->action[sig-1].sa.sa_handler == SIG_IGN) | |
915 | t->sighand->action[sig-1].sa.sa_handler = SIG_DFL; | |
916 | sigdelset(&t->blocked, sig); | |
917 | recalc_sigpending_tsk(t); | |
918 | specific_send_sig_info(sig, (void *)2, t); | |
919 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
920 | } | |
921 | ||
922 | /* | |
923 | * Test if P wants to take SIG. After we've checked all threads with this, | |
924 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
925 | * blocking SIG were ruled out because they are not running and already | |
926 | * have pending signals. Such threads will dequeue from the shared queue | |
927 | * as soon as they're available, so putting the signal on the shared queue | |
928 | * will be equivalent to sending it to one such thread. | |
929 | */ | |
188a1eaf LT |
930 | static inline int wants_signal(int sig, struct task_struct *p) |
931 | { | |
932 | if (sigismember(&p->blocked, sig)) | |
933 | return 0; | |
934 | if (p->flags & PF_EXITING) | |
935 | return 0; | |
936 | if (sig == SIGKILL) | |
937 | return 1; | |
938 | if (p->state & (TASK_STOPPED | TASK_TRACED)) | |
939 | return 0; | |
940 | return task_curr(p) || !signal_pending(p); | |
941 | } | |
1da177e4 LT |
942 | |
943 | static void | |
944 | __group_complete_signal(int sig, struct task_struct *p) | |
945 | { | |
1da177e4 LT |
946 | struct task_struct *t; |
947 | ||
1da177e4 LT |
948 | /* |
949 | * Now find a thread we can wake up to take the signal off the queue. | |
950 | * | |
951 | * If the main thread wants the signal, it gets first crack. | |
952 | * Probably the least surprising to the average bear. | |
953 | */ | |
188a1eaf | 954 | if (wants_signal(sig, p)) |
1da177e4 LT |
955 | t = p; |
956 | else if (thread_group_empty(p)) | |
957 | /* | |
958 | * There is just one thread and it does not need to be woken. | |
959 | * It will dequeue unblocked signals before it runs again. | |
960 | */ | |
961 | return; | |
962 | else { | |
963 | /* | |
964 | * Otherwise try to find a suitable thread. | |
965 | */ | |
966 | t = p->signal->curr_target; | |
967 | if (t == NULL) | |
968 | /* restart balancing at this thread */ | |
969 | t = p->signal->curr_target = p; | |
970 | BUG_ON(t->tgid != p->tgid); | |
971 | ||
188a1eaf | 972 | while (!wants_signal(sig, t)) { |
1da177e4 LT |
973 | t = next_thread(t); |
974 | if (t == p->signal->curr_target) | |
975 | /* | |
976 | * No thread needs to be woken. | |
977 | * Any eligible threads will see | |
978 | * the signal in the queue soon. | |
979 | */ | |
980 | return; | |
981 | } | |
982 | p->signal->curr_target = t; | |
983 | } | |
984 | ||
985 | /* | |
986 | * Found a killable thread. If the signal will be fatal, | |
987 | * then start taking the whole group down immediately. | |
988 | */ | |
989 | if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) && | |
990 | !sigismember(&t->real_blocked, sig) && | |
991 | (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { | |
992 | /* | |
993 | * This signal will be fatal to the whole group. | |
994 | */ | |
995 | if (!sig_kernel_coredump(sig)) { | |
996 | /* | |
997 | * Start a group exit and wake everybody up. | |
998 | * This way we don't have other threads | |
999 | * running and doing things after a slower | |
1000 | * thread has the fatal signal pending. | |
1001 | */ | |
1002 | p->signal->flags = SIGNAL_GROUP_EXIT; | |
1003 | p->signal->group_exit_code = sig; | |
1004 | p->signal->group_stop_count = 0; | |
1005 | t = p; | |
1006 | do { | |
1007 | sigaddset(&t->pending.signal, SIGKILL); | |
1008 | signal_wake_up(t, 1); | |
1009 | t = next_thread(t); | |
1010 | } while (t != p); | |
1011 | return; | |
1012 | } | |
1013 | ||
1014 | /* | |
1015 | * There will be a core dump. We make all threads other | |
1016 | * than the chosen one go into a group stop so that nothing | |
1017 | * happens until it gets scheduled, takes the signal off | |
1018 | * the shared queue, and does the core dump. This is a | |
1019 | * little more complicated than strictly necessary, but it | |
1020 | * keeps the signal state that winds up in the core dump | |
1021 | * unchanged from the death state, e.g. which thread had | |
1022 | * the core-dump signal unblocked. | |
1023 | */ | |
1024 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
1025 | rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); | |
1026 | p->signal->group_stop_count = 0; | |
1027 | p->signal->group_exit_task = t; | |
1028 | t = p; | |
1029 | do { | |
1030 | p->signal->group_stop_count++; | |
1031 | signal_wake_up(t, 0); | |
1032 | t = next_thread(t); | |
1033 | } while (t != p); | |
1034 | wake_up_process(p->signal->group_exit_task); | |
1035 | return; | |
1036 | } | |
1037 | ||
1038 | /* | |
1039 | * The signal is already in the shared-pending queue. | |
1040 | * Tell the chosen thread to wake up and dequeue it. | |
1041 | */ | |
1042 | signal_wake_up(t, sig == SIGKILL); | |
1043 | return; | |
1044 | } | |
1045 | ||
1046 | int | |
1047 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1048 | { | |
1049 | int ret = 0; | |
1050 | ||
1051 | assert_spin_locked(&p->sighand->siglock); | |
1052 | handle_stop_signal(sig, p); | |
1053 | ||
1054 | if (((unsigned long)info > 2) && (info->si_code == SI_TIMER)) | |
1055 | /* | |
1056 | * Set up a return to indicate that we dropped the signal. | |
1057 | */ | |
1058 | ret = info->si_sys_private; | |
1059 | ||
1060 | /* Short-circuit ignored signals. */ | |
1061 | if (sig_ignored(p, sig)) | |
1062 | return ret; | |
1063 | ||
1064 | if (LEGACY_QUEUE(&p->signal->shared_pending, sig)) | |
1065 | /* This is a non-RT signal and we already have one queued. */ | |
1066 | return ret; | |
1067 | ||
1068 | /* | |
1069 | * Put this signal on the shared-pending queue, or fail with EAGAIN. | |
1070 | * We always use the shared queue for process-wide signals, | |
1071 | * to avoid several races. | |
1072 | */ | |
1073 | ret = send_signal(sig, info, p, &p->signal->shared_pending); | |
1074 | if (unlikely(ret)) | |
1075 | return ret; | |
1076 | ||
1077 | __group_complete_signal(sig, p); | |
1078 | return 0; | |
1079 | } | |
1080 | ||
1081 | /* | |
1082 | * Nuke all other threads in the group. | |
1083 | */ | |
1084 | void zap_other_threads(struct task_struct *p) | |
1085 | { | |
1086 | struct task_struct *t; | |
1087 | ||
1088 | p->signal->flags = SIGNAL_GROUP_EXIT; | |
1089 | p->signal->group_stop_count = 0; | |
1090 | ||
1091 | if (thread_group_empty(p)) | |
1092 | return; | |
1093 | ||
1094 | for (t = next_thread(p); t != p; t = next_thread(t)) { | |
1095 | /* | |
1096 | * Don't bother with already dead threads | |
1097 | */ | |
1098 | if (t->exit_state) | |
1099 | continue; | |
1100 | ||
1101 | /* | |
1102 | * We don't want to notify the parent, since we are | |
1103 | * killed as part of a thread group due to another | |
1104 | * thread doing an execve() or similar. So set the | |
1105 | * exit signal to -1 to allow immediate reaping of | |
1106 | * the process. But don't detach the thread group | |
1107 | * leader. | |
1108 | */ | |
1109 | if (t != p->group_leader) | |
1110 | t->exit_signal = -1; | |
1111 | ||
1112 | sigaddset(&t->pending.signal, SIGKILL); | |
1113 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
1114 | signal_wake_up(t, 1); | |
1115 | } | |
1116 | } | |
1117 | ||
1118 | /* | |
1119 | * Must be called with the tasklist_lock held for reading! | |
1120 | */ | |
1121 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1122 | { | |
1123 | unsigned long flags; | |
1124 | int ret; | |
1125 | ||
1126 | ret = check_kill_permission(sig, info, p); | |
1127 | if (!ret && sig && p->sighand) { | |
1128 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1129 | ret = __group_send_sig_info(sig, info, p); | |
1130 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1131 | } | |
1132 | ||
1133 | return ret; | |
1134 | } | |
1135 | ||
1136 | /* | |
1137 | * kill_pg_info() sends a signal to a process group: this is what the tty | |
1138 | * control characters do (^C, ^Z etc) | |
1139 | */ | |
1140 | ||
1141 | int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) | |
1142 | { | |
1143 | struct task_struct *p = NULL; | |
1144 | int retval, success; | |
1145 | ||
1146 | if (pgrp <= 0) | |
1147 | return -EINVAL; | |
1148 | ||
1149 | success = 0; | |
1150 | retval = -ESRCH; | |
1151 | do_each_task_pid(pgrp, PIDTYPE_PGID, p) { | |
1152 | int err = group_send_sig_info(sig, info, p); | |
1153 | success |= !err; | |
1154 | retval = err; | |
1155 | } while_each_task_pid(pgrp, PIDTYPE_PGID, p); | |
1156 | return success ? 0 : retval; | |
1157 | } | |
1158 | ||
1159 | int | |
1160 | kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) | |
1161 | { | |
1162 | int retval; | |
1163 | ||
1164 | read_lock(&tasklist_lock); | |
1165 | retval = __kill_pg_info(sig, info, pgrp); | |
1166 | read_unlock(&tasklist_lock); | |
1167 | ||
1168 | return retval; | |
1169 | } | |
1170 | ||
1171 | int | |
1172 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
1173 | { | |
1174 | int error; | |
1175 | struct task_struct *p; | |
1176 | ||
1177 | read_lock(&tasklist_lock); | |
1178 | p = find_task_by_pid(pid); | |
1179 | error = -ESRCH; | |
1180 | if (p) | |
1181 | error = group_send_sig_info(sig, info, p); | |
1182 | read_unlock(&tasklist_lock); | |
1183 | return error; | |
1184 | } | |
1185 | ||
46113830 HW |
1186 | /* like kill_proc_info(), but doesn't use uid/euid of "current" */ |
1187 | int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid, | |
1188 | uid_t uid, uid_t euid) | |
1189 | { | |
1190 | int ret = -EINVAL; | |
1191 | struct task_struct *p; | |
1192 | ||
1193 | if (!valid_signal(sig)) | |
1194 | return ret; | |
1195 | ||
1196 | read_lock(&tasklist_lock); | |
1197 | p = find_task_by_pid(pid); | |
1198 | if (!p) { | |
1199 | ret = -ESRCH; | |
1200 | goto out_unlock; | |
1201 | } | |
1202 | if ((!info || ((unsigned long)info != 1 && | |
1203 | (unsigned long)info != 2 && SI_FROMUSER(info))) | |
1204 | && (euid != p->suid) && (euid != p->uid) | |
1205 | && (uid != p->suid) && (uid != p->uid)) { | |
1206 | ret = -EPERM; | |
1207 | goto out_unlock; | |
1208 | } | |
1209 | if (sig && p->sighand) { | |
1210 | unsigned long flags; | |
1211 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1212 | ret = __group_send_sig_info(sig, info, p); | |
1213 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1214 | } | |
1215 | out_unlock: | |
1216 | read_unlock(&tasklist_lock); | |
1217 | return ret; | |
1218 | } | |
1219 | EXPORT_SYMBOL_GPL(kill_proc_info_as_uid); | |
1da177e4 LT |
1220 | |
1221 | /* | |
1222 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1223 | * | |
1224 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1225 | * is probably wrong. Should make it like BSD or SYSV. | |
1226 | */ | |
1227 | ||
1228 | static int kill_something_info(int sig, struct siginfo *info, int pid) | |
1229 | { | |
1230 | if (!pid) { | |
1231 | return kill_pg_info(sig, info, process_group(current)); | |
1232 | } else if (pid == -1) { | |
1233 | int retval = 0, count = 0; | |
1234 | struct task_struct * p; | |
1235 | ||
1236 | read_lock(&tasklist_lock); | |
1237 | for_each_process(p) { | |
1238 | if (p->pid > 1 && p->tgid != current->tgid) { | |
1239 | int err = group_send_sig_info(sig, info, p); | |
1240 | ++count; | |
1241 | if (err != -EPERM) | |
1242 | retval = err; | |
1243 | } | |
1244 | } | |
1245 | read_unlock(&tasklist_lock); | |
1246 | return count ? retval : -ESRCH; | |
1247 | } else if (pid < 0) { | |
1248 | return kill_pg_info(sig, info, -pid); | |
1249 | } else { | |
1250 | return kill_proc_info(sig, info, pid); | |
1251 | } | |
1252 | } | |
1253 | ||
1254 | /* | |
1255 | * These are for backward compatibility with the rest of the kernel source. | |
1256 | */ | |
1257 | ||
1258 | /* | |
1259 | * These two are the most common entry points. They send a signal | |
1260 | * just to the specific thread. | |
1261 | */ | |
1262 | int | |
1263 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1264 | { | |
1265 | int ret; | |
1266 | unsigned long flags; | |
1267 | ||
1268 | /* | |
1269 | * Make sure legacy kernel users don't send in bad values | |
1270 | * (normal paths check this in check_kill_permission). | |
1271 | */ | |
7ed20e1a | 1272 | if (!valid_signal(sig)) |
1da177e4 LT |
1273 | return -EINVAL; |
1274 | ||
1275 | /* | |
1276 | * We need the tasklist lock even for the specific | |
1277 | * thread case (when we don't need to follow the group | |
1278 | * lists) in order to avoid races with "p->sighand" | |
1279 | * going away or changing from under us. | |
1280 | */ | |
1281 | read_lock(&tasklist_lock); | |
1282 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1283 | ret = specific_send_sig_info(sig, info, p); | |
1284 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1285 | read_unlock(&tasklist_lock); | |
1286 | return ret; | |
1287 | } | |
1288 | ||
1289 | int | |
1290 | send_sig(int sig, struct task_struct *p, int priv) | |
1291 | { | |
1292 | return send_sig_info(sig, (void*)(long)(priv != 0), p); | |
1293 | } | |
1294 | ||
1295 | /* | |
1296 | * This is the entry point for "process-wide" signals. | |
1297 | * They will go to an appropriate thread in the thread group. | |
1298 | */ | |
1299 | int | |
1300 | send_group_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1301 | { | |
1302 | int ret; | |
1303 | read_lock(&tasklist_lock); | |
1304 | ret = group_send_sig_info(sig, info, p); | |
1305 | read_unlock(&tasklist_lock); | |
1306 | return ret; | |
1307 | } | |
1308 | ||
1309 | void | |
1310 | force_sig(int sig, struct task_struct *p) | |
1311 | { | |
1312 | force_sig_info(sig, (void*)1L, p); | |
1313 | } | |
1314 | ||
1315 | /* | |
1316 | * When things go south during signal handling, we | |
1317 | * will force a SIGSEGV. And if the signal that caused | |
1318 | * the problem was already a SIGSEGV, we'll want to | |
1319 | * make sure we don't even try to deliver the signal.. | |
1320 | */ | |
1321 | int | |
1322 | force_sigsegv(int sig, struct task_struct *p) | |
1323 | { | |
1324 | if (sig == SIGSEGV) { | |
1325 | unsigned long flags; | |
1326 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1327 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1328 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1329 | } | |
1330 | force_sig(SIGSEGV, p); | |
1331 | return 0; | |
1332 | } | |
1333 | ||
1334 | int | |
1335 | kill_pg(pid_t pgrp, int sig, int priv) | |
1336 | { | |
1337 | return kill_pg_info(sig, (void *)(long)(priv != 0), pgrp); | |
1338 | } | |
1339 | ||
1340 | int | |
1341 | kill_proc(pid_t pid, int sig, int priv) | |
1342 | { | |
1343 | return kill_proc_info(sig, (void *)(long)(priv != 0), pid); | |
1344 | } | |
1345 | ||
1346 | /* | |
1347 | * These functions support sending signals using preallocated sigqueue | |
1348 | * structures. This is needed "because realtime applications cannot | |
1349 | * afford to lose notifications of asynchronous events, like timer | |
1350 | * expirations or I/O completions". In the case of Posix Timers | |
1351 | * we allocate the sigqueue structure from the timer_create. If this | |
1352 | * allocation fails we are able to report the failure to the application | |
1353 | * with an EAGAIN error. | |
1354 | */ | |
1355 | ||
1356 | struct sigqueue *sigqueue_alloc(void) | |
1357 | { | |
1358 | struct sigqueue *q; | |
1359 | ||
1360 | if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) | |
1361 | q->flags |= SIGQUEUE_PREALLOC; | |
1362 | return(q); | |
1363 | } | |
1364 | ||
1365 | void sigqueue_free(struct sigqueue *q) | |
1366 | { | |
1367 | unsigned long flags; | |
1368 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); | |
1369 | /* | |
1370 | * If the signal is still pending remove it from the | |
1371 | * pending queue. | |
1372 | */ | |
1373 | if (unlikely(!list_empty(&q->list))) { | |
1374 | read_lock(&tasklist_lock); | |
1375 | spin_lock_irqsave(q->lock, flags); | |
1376 | if (!list_empty(&q->list)) | |
1377 | list_del_init(&q->list); | |
1378 | spin_unlock_irqrestore(q->lock, flags); | |
1379 | read_unlock(&tasklist_lock); | |
1380 | } | |
1381 | q->flags &= ~SIGQUEUE_PREALLOC; | |
1382 | __sigqueue_free(q); | |
1383 | } | |
1384 | ||
1385 | int | |
1386 | send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) | |
1387 | { | |
1388 | unsigned long flags; | |
1389 | int ret = 0; | |
1390 | ||
1da177e4 | 1391 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e752dd6c ON |
1392 | read_lock(&tasklist_lock); |
1393 | ||
1394 | if (unlikely(p->flags & PF_EXITING)) { | |
1395 | ret = -1; | |
1396 | goto out_err; | |
1397 | } | |
1398 | ||
1da177e4 | 1399 | spin_lock_irqsave(&p->sighand->siglock, flags); |
e752dd6c | 1400 | |
1da177e4 LT |
1401 | if (unlikely(!list_empty(&q->list))) { |
1402 | /* | |
1403 | * If an SI_TIMER entry is already queue just increment | |
1404 | * the overrun count. | |
1405 | */ | |
1406 | if (q->info.si_code != SI_TIMER) | |
1407 | BUG(); | |
1408 | q->info.si_overrun++; | |
1409 | goto out; | |
e752dd6c | 1410 | } |
1da177e4 LT |
1411 | /* Short-circuit ignored signals. */ |
1412 | if (sig_ignored(p, sig)) { | |
1413 | ret = 1; | |
1414 | goto out; | |
1415 | } | |
1416 | ||
1417 | q->lock = &p->sighand->siglock; | |
1418 | list_add_tail(&q->list, &p->pending.list); | |
1419 | sigaddset(&p->pending.signal, sig); | |
1420 | if (!sigismember(&p->blocked, sig)) | |
1421 | signal_wake_up(p, sig == SIGKILL); | |
1422 | ||
1423 | out: | |
1424 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
e752dd6c | 1425 | out_err: |
1da177e4 | 1426 | read_unlock(&tasklist_lock); |
e752dd6c ON |
1427 | |
1428 | return ret; | |
1da177e4 LT |
1429 | } |
1430 | ||
1431 | int | |
1432 | send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) | |
1433 | { | |
1434 | unsigned long flags; | |
1435 | int ret = 0; | |
1436 | ||
1437 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); | |
1438 | read_lock(&tasklist_lock); | |
1439 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1440 | handle_stop_signal(sig, p); | |
1441 | ||
1442 | /* Short-circuit ignored signals. */ | |
1443 | if (sig_ignored(p, sig)) { | |
1444 | ret = 1; | |
1445 | goto out; | |
1446 | } | |
1447 | ||
1448 | if (unlikely(!list_empty(&q->list))) { | |
1449 | /* | |
1450 | * If an SI_TIMER entry is already queue just increment | |
1451 | * the overrun count. Other uses should not try to | |
1452 | * send the signal multiple times. | |
1453 | */ | |
1454 | if (q->info.si_code != SI_TIMER) | |
1455 | BUG(); | |
1456 | q->info.si_overrun++; | |
1457 | goto out; | |
1458 | } | |
1459 | ||
1460 | /* | |
1461 | * Put this signal on the shared-pending queue. | |
1462 | * We always use the shared queue for process-wide signals, | |
1463 | * to avoid several races. | |
1464 | */ | |
1465 | q->lock = &p->sighand->siglock; | |
1466 | list_add_tail(&q->list, &p->signal->shared_pending.list); | |
1467 | sigaddset(&p->signal->shared_pending.signal, sig); | |
1468 | ||
1469 | __group_complete_signal(sig, p); | |
1470 | out: | |
1471 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1472 | read_unlock(&tasklist_lock); | |
1473 | return(ret); | |
1474 | } | |
1475 | ||
1476 | /* | |
1477 | * Wake up any threads in the parent blocked in wait* syscalls. | |
1478 | */ | |
1479 | static inline void __wake_up_parent(struct task_struct *p, | |
1480 | struct task_struct *parent) | |
1481 | { | |
1482 | wake_up_interruptible_sync(&parent->signal->wait_chldexit); | |
1483 | } | |
1484 | ||
1485 | /* | |
1486 | * Let a parent know about the death of a child. | |
1487 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
1488 | */ | |
1489 | ||
1490 | void do_notify_parent(struct task_struct *tsk, int sig) | |
1491 | { | |
1492 | struct siginfo info; | |
1493 | unsigned long flags; | |
1494 | struct sighand_struct *psig; | |
1495 | ||
1496 | BUG_ON(sig == -1); | |
1497 | ||
1498 | /* do_notify_parent_cldstop should have been called instead. */ | |
1499 | BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); | |
1500 | ||
1501 | BUG_ON(!tsk->ptrace && | |
1502 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); | |
1503 | ||
1504 | info.si_signo = sig; | |
1505 | info.si_errno = 0; | |
1506 | info.si_pid = tsk->pid; | |
1507 | info.si_uid = tsk->uid; | |
1508 | ||
1509 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1510 | info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime, | |
1511 | tsk->signal->utime)); | |
1512 | info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime, | |
1513 | tsk->signal->stime)); | |
1514 | ||
1515 | info.si_status = tsk->exit_code & 0x7f; | |
1516 | if (tsk->exit_code & 0x80) | |
1517 | info.si_code = CLD_DUMPED; | |
1518 | else if (tsk->exit_code & 0x7f) | |
1519 | info.si_code = CLD_KILLED; | |
1520 | else { | |
1521 | info.si_code = CLD_EXITED; | |
1522 | info.si_status = tsk->exit_code >> 8; | |
1523 | } | |
1524 | ||
1525 | psig = tsk->parent->sighand; | |
1526 | spin_lock_irqsave(&psig->siglock, flags); | |
1527 | if (sig == SIGCHLD && | |
1528 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || | |
1529 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1530 | /* | |
1531 | * We are exiting and our parent doesn't care. POSIX.1 | |
1532 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1533 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1534 | * automatically and not left for our parent's wait4 call. | |
1535 | * Rather than having the parent do it as a magic kind of | |
1536 | * signal handler, we just set this to tell do_exit that we | |
1537 | * can be cleaned up without becoming a zombie. Note that | |
1538 | * we still call __wake_up_parent in this case, because a | |
1539 | * blocked sys_wait4 might now return -ECHILD. | |
1540 | * | |
1541 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1542 | * is implementation-defined: we do (if you don't want | |
1543 | * it, just use SIG_IGN instead). | |
1544 | */ | |
1545 | tsk->exit_signal = -1; | |
1546 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) | |
1547 | sig = 0; | |
1548 | } | |
7ed20e1a | 1549 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1550 | __group_send_sig_info(sig, &info, tsk->parent); |
1551 | __wake_up_parent(tsk, tsk->parent); | |
1552 | spin_unlock_irqrestore(&psig->siglock, flags); | |
1553 | } | |
1554 | ||
bc505a47 | 1555 | static void do_notify_parent_cldstop(struct task_struct *tsk, int to_self, int why) |
1da177e4 LT |
1556 | { |
1557 | struct siginfo info; | |
1558 | unsigned long flags; | |
bc505a47 | 1559 | struct task_struct *parent; |
1da177e4 LT |
1560 | struct sighand_struct *sighand; |
1561 | ||
bc505a47 ON |
1562 | if (to_self) |
1563 | parent = tsk->parent; | |
1564 | else { | |
1565 | tsk = tsk->group_leader; | |
1566 | parent = tsk->real_parent; | |
1567 | } | |
1568 | ||
1da177e4 LT |
1569 | info.si_signo = SIGCHLD; |
1570 | info.si_errno = 0; | |
1571 | info.si_pid = tsk->pid; | |
1572 | info.si_uid = tsk->uid; | |
1573 | ||
1574 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1575 | info.si_utime = cputime_to_jiffies(tsk->utime); | |
1576 | info.si_stime = cputime_to_jiffies(tsk->stime); | |
1577 | ||
1578 | info.si_code = why; | |
1579 | switch (why) { | |
1580 | case CLD_CONTINUED: | |
1581 | info.si_status = SIGCONT; | |
1582 | break; | |
1583 | case CLD_STOPPED: | |
1584 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1585 | break; | |
1586 | case CLD_TRAPPED: | |
1587 | info.si_status = tsk->exit_code & 0x7f; | |
1588 | break; | |
1589 | default: | |
1590 | BUG(); | |
1591 | } | |
1592 | ||
1593 | sighand = parent->sighand; | |
1594 | spin_lock_irqsave(&sighand->siglock, flags); | |
1595 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1596 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1597 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1598 | /* | |
1599 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1600 | */ | |
1601 | __wake_up_parent(tsk, parent); | |
1602 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * This must be called with current->sighand->siglock held. | |
1607 | * | |
1608 | * This should be the path for all ptrace stops. | |
1609 | * We always set current->last_siginfo while stopped here. | |
1610 | * That makes it a way to test a stopped process for | |
1611 | * being ptrace-stopped vs being job-control-stopped. | |
1612 | * | |
1613 | * If we actually decide not to stop at all because the tracer is gone, | |
1614 | * we leave nostop_code in current->exit_code. | |
1615 | */ | |
1616 | static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) | |
1617 | { | |
1618 | /* | |
1619 | * If there is a group stop in progress, | |
1620 | * we must participate in the bookkeeping. | |
1621 | */ | |
1622 | if (current->signal->group_stop_count > 0) | |
1623 | --current->signal->group_stop_count; | |
1624 | ||
1625 | current->last_siginfo = info; | |
1626 | current->exit_code = exit_code; | |
1627 | ||
1628 | /* Let the debugger run. */ | |
1629 | set_current_state(TASK_TRACED); | |
1630 | spin_unlock_irq(¤t->sighand->siglock); | |
1631 | read_lock(&tasklist_lock); | |
1632 | if (likely(current->ptrace & PT_PTRACED) && | |
1633 | likely(current->parent != current->real_parent || | |
1634 | !(current->ptrace & PT_ATTACHED)) && | |
1635 | (likely(current->parent->signal != current->signal) || | |
1636 | !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) { | |
bc505a47 | 1637 | do_notify_parent_cldstop(current, 1, CLD_TRAPPED); |
1da177e4 LT |
1638 | read_unlock(&tasklist_lock); |
1639 | schedule(); | |
1640 | } else { | |
1641 | /* | |
1642 | * By the time we got the lock, our tracer went away. | |
1643 | * Don't stop here. | |
1644 | */ | |
1645 | read_unlock(&tasklist_lock); | |
1646 | set_current_state(TASK_RUNNING); | |
1647 | current->exit_code = nostop_code; | |
1648 | } | |
1649 | ||
1650 | /* | |
1651 | * We are back. Now reacquire the siglock before touching | |
1652 | * last_siginfo, so that we are sure to have synchronized with | |
1653 | * any signal-sending on another CPU that wants to examine it. | |
1654 | */ | |
1655 | spin_lock_irq(¤t->sighand->siglock); | |
1656 | current->last_siginfo = NULL; | |
1657 | ||
1658 | /* | |
1659 | * Queued signals ignored us while we were stopped for tracing. | |
1660 | * So check for any that we should take before resuming user mode. | |
1661 | */ | |
1662 | recalc_sigpending(); | |
1663 | } | |
1664 | ||
1665 | void ptrace_notify(int exit_code) | |
1666 | { | |
1667 | siginfo_t info; | |
1668 | ||
1669 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1670 | ||
1671 | memset(&info, 0, sizeof info); | |
1672 | info.si_signo = SIGTRAP; | |
1673 | info.si_code = exit_code; | |
1674 | info.si_pid = current->pid; | |
1675 | info.si_uid = current->uid; | |
1676 | ||
1677 | /* Let the debugger run. */ | |
1678 | spin_lock_irq(¤t->sighand->siglock); | |
1679 | ptrace_stop(exit_code, 0, &info); | |
1680 | spin_unlock_irq(¤t->sighand->siglock); | |
1681 | } | |
1682 | ||
1da177e4 LT |
1683 | static void |
1684 | finish_stop(int stop_count) | |
1685 | { | |
bc505a47 ON |
1686 | int to_self; |
1687 | ||
1da177e4 LT |
1688 | /* |
1689 | * If there are no other threads in the group, or if there is | |
1690 | * a group stop in progress and we are the last to stop, | |
1691 | * report to the parent. When ptraced, every thread reports itself. | |
1692 | */ | |
bc505a47 ON |
1693 | if (stop_count < 0 || (current->ptrace & PT_PTRACED)) |
1694 | to_self = 1; | |
1695 | else if (stop_count == 0) | |
1696 | to_self = 0; | |
1697 | else | |
1698 | goto out; | |
1da177e4 | 1699 | |
bc505a47 ON |
1700 | read_lock(&tasklist_lock); |
1701 | do_notify_parent_cldstop(current, to_self, CLD_STOPPED); | |
1702 | read_unlock(&tasklist_lock); | |
1703 | ||
1704 | out: | |
1da177e4 LT |
1705 | schedule(); |
1706 | /* | |
1707 | * Now we don't run again until continued. | |
1708 | */ | |
1709 | current->exit_code = 0; | |
1710 | } | |
1711 | ||
1712 | /* | |
1713 | * This performs the stopping for SIGSTOP and other stop signals. | |
1714 | * We have to stop all threads in the thread group. | |
1715 | * Returns nonzero if we've actually stopped and released the siglock. | |
1716 | * Returns zero if we didn't stop and still hold the siglock. | |
1717 | */ | |
1718 | static int | |
1719 | do_signal_stop(int signr) | |
1720 | { | |
1721 | struct signal_struct *sig = current->signal; | |
1722 | struct sighand_struct *sighand = current->sighand; | |
1723 | int stop_count = -1; | |
1724 | ||
1725 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) | |
1726 | return 0; | |
1727 | ||
1728 | if (sig->group_stop_count > 0) { | |
1729 | /* | |
1730 | * There is a group stop in progress. We don't need to | |
1731 | * start another one. | |
1732 | */ | |
1733 | signr = sig->group_exit_code; | |
1734 | stop_count = --sig->group_stop_count; | |
1735 | current->exit_code = signr; | |
1736 | set_current_state(TASK_STOPPED); | |
1737 | if (stop_count == 0) | |
1738 | sig->flags = SIGNAL_STOP_STOPPED; | |
1739 | spin_unlock_irq(&sighand->siglock); | |
1740 | } | |
1741 | else if (thread_group_empty(current)) { | |
1742 | /* | |
1743 | * Lock must be held through transition to stopped state. | |
1744 | */ | |
1745 | current->exit_code = current->signal->group_exit_code = signr; | |
1746 | set_current_state(TASK_STOPPED); | |
1747 | sig->flags = SIGNAL_STOP_STOPPED; | |
1748 | spin_unlock_irq(&sighand->siglock); | |
1749 | } | |
1750 | else { | |
1751 | /* | |
1752 | * There is no group stop already in progress. | |
1753 | * We must initiate one now, but that requires | |
1754 | * dropping siglock to get both the tasklist lock | |
1755 | * and siglock again in the proper order. Note that | |
1756 | * this allows an intervening SIGCONT to be posted. | |
1757 | * We need to check for that and bail out if necessary. | |
1758 | */ | |
1759 | struct task_struct *t; | |
1760 | ||
1761 | spin_unlock_irq(&sighand->siglock); | |
1762 | ||
1763 | /* signals can be posted during this window */ | |
1764 | ||
1765 | read_lock(&tasklist_lock); | |
1766 | spin_lock_irq(&sighand->siglock); | |
1767 | ||
1768 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) { | |
1769 | /* | |
1770 | * Another stop or continue happened while we | |
1771 | * didn't have the lock. We can just swallow this | |
1772 | * signal now. If we raced with a SIGCONT, that | |
1773 | * should have just cleared it now. If we raced | |
1774 | * with another processor delivering a stop signal, | |
1775 | * then the SIGCONT that wakes us up should clear it. | |
1776 | */ | |
1777 | read_unlock(&tasklist_lock); | |
1778 | return 0; | |
1779 | } | |
1780 | ||
1781 | if (sig->group_stop_count == 0) { | |
1782 | sig->group_exit_code = signr; | |
1783 | stop_count = 0; | |
1784 | for (t = next_thread(current); t != current; | |
1785 | t = next_thread(t)) | |
1786 | /* | |
1787 | * Setting state to TASK_STOPPED for a group | |
1788 | * stop is always done with the siglock held, | |
1789 | * so this check has no races. | |
1790 | */ | |
5acbc5cb RM |
1791 | if (!t->exit_state && |
1792 | !(t->state & (TASK_STOPPED|TASK_TRACED))) { | |
1da177e4 LT |
1793 | stop_count++; |
1794 | signal_wake_up(t, 0); | |
1795 | } | |
1796 | sig->group_stop_count = stop_count; | |
1797 | } | |
1798 | else { | |
1799 | /* A race with another thread while unlocked. */ | |
1800 | signr = sig->group_exit_code; | |
1801 | stop_count = --sig->group_stop_count; | |
1802 | } | |
1803 | ||
1804 | current->exit_code = signr; | |
1805 | set_current_state(TASK_STOPPED); | |
1806 | if (stop_count == 0) | |
1807 | sig->flags = SIGNAL_STOP_STOPPED; | |
1808 | ||
1809 | spin_unlock_irq(&sighand->siglock); | |
1810 | read_unlock(&tasklist_lock); | |
1811 | } | |
1812 | ||
1813 | finish_stop(stop_count); | |
1814 | return 1; | |
1815 | } | |
1816 | ||
1817 | /* | |
1818 | * Do appropriate magic when group_stop_count > 0. | |
1819 | * We return nonzero if we stopped, after releasing the siglock. | |
1820 | * We return zero if we still hold the siglock and should look | |
1821 | * for another signal without checking group_stop_count again. | |
1822 | */ | |
1823 | static inline int handle_group_stop(void) | |
1824 | { | |
1825 | int stop_count; | |
1826 | ||
1827 | if (current->signal->group_exit_task == current) { | |
1828 | /* | |
1829 | * Group stop is so we can do a core dump, | |
1830 | * We are the initiating thread, so get on with it. | |
1831 | */ | |
1832 | current->signal->group_exit_task = NULL; | |
1833 | return 0; | |
1834 | } | |
1835 | ||
1836 | if (current->signal->flags & SIGNAL_GROUP_EXIT) | |
1837 | /* | |
1838 | * Group stop is so another thread can do a core dump, | |
1839 | * or else we are racing against a death signal. | |
1840 | * Just punt the stop so we can get the next signal. | |
1841 | */ | |
1842 | return 0; | |
1843 | ||
1844 | /* | |
1845 | * There is a group stop in progress. We stop | |
1846 | * without any associated signal being in our queue. | |
1847 | */ | |
1848 | stop_count = --current->signal->group_stop_count; | |
1849 | if (stop_count == 0) | |
1850 | current->signal->flags = SIGNAL_STOP_STOPPED; | |
1851 | current->exit_code = current->signal->group_exit_code; | |
1852 | set_current_state(TASK_STOPPED); | |
1853 | spin_unlock_irq(¤t->sighand->siglock); | |
1854 | finish_stop(stop_count); | |
1855 | return 1; | |
1856 | } | |
1857 | ||
1858 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, | |
1859 | struct pt_regs *regs, void *cookie) | |
1860 | { | |
1861 | sigset_t *mask = ¤t->blocked; | |
1862 | int signr = 0; | |
1863 | ||
1864 | relock: | |
1865 | spin_lock_irq(¤t->sighand->siglock); | |
1866 | for (;;) { | |
1867 | struct k_sigaction *ka; | |
1868 | ||
1869 | if (unlikely(current->signal->group_stop_count > 0) && | |
1870 | handle_group_stop()) | |
1871 | goto relock; | |
1872 | ||
1873 | signr = dequeue_signal(current, mask, info); | |
1874 | ||
1875 | if (!signr) | |
1876 | break; /* will return 0 */ | |
1877 | ||
1878 | if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) { | |
1879 | ptrace_signal_deliver(regs, cookie); | |
1880 | ||
1881 | /* Let the debugger run. */ | |
1882 | ptrace_stop(signr, signr, info); | |
1883 | ||
1884 | /* We're back. Did the debugger cancel the sig? */ | |
1885 | signr = current->exit_code; | |
1886 | if (signr == 0) | |
1887 | continue; | |
1888 | ||
1889 | current->exit_code = 0; | |
1890 | ||
1891 | /* Update the siginfo structure if the signal has | |
1892 | changed. If the debugger wanted something | |
1893 | specific in the siginfo structure then it should | |
1894 | have updated *info via PTRACE_SETSIGINFO. */ | |
1895 | if (signr != info->si_signo) { | |
1896 | info->si_signo = signr; | |
1897 | info->si_errno = 0; | |
1898 | info->si_code = SI_USER; | |
1899 | info->si_pid = current->parent->pid; | |
1900 | info->si_uid = current->parent->uid; | |
1901 | } | |
1902 | ||
1903 | /* If the (new) signal is now blocked, requeue it. */ | |
1904 | if (sigismember(¤t->blocked, signr)) { | |
1905 | specific_send_sig_info(signr, info, current); | |
1906 | continue; | |
1907 | } | |
1908 | } | |
1909 | ||
1910 | ka = ¤t->sighand->action[signr-1]; | |
1911 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ | |
1912 | continue; | |
1913 | if (ka->sa.sa_handler != SIG_DFL) { | |
1914 | /* Run the handler. */ | |
1915 | *return_ka = *ka; | |
1916 | ||
1917 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1918 | ka->sa.sa_handler = SIG_DFL; | |
1919 | ||
1920 | break; /* will return non-zero "signr" value */ | |
1921 | } | |
1922 | ||
1923 | /* | |
1924 | * Now we are doing the default action for this signal. | |
1925 | */ | |
1926 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1927 | continue; | |
1928 | ||
1929 | /* Init gets no signals it doesn't want. */ | |
1930 | if (current->pid == 1) | |
1931 | continue; | |
1932 | ||
1933 | if (sig_kernel_stop(signr)) { | |
1934 | /* | |
1935 | * The default action is to stop all threads in | |
1936 | * the thread group. The job control signals | |
1937 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1938 | * always works. Note that siglock needs to be | |
1939 | * dropped during the call to is_orphaned_pgrp() | |
1940 | * because of lock ordering with tasklist_lock. | |
1941 | * This allows an intervening SIGCONT to be posted. | |
1942 | * We need to check for that and bail out if necessary. | |
1943 | */ | |
1944 | if (signr != SIGSTOP) { | |
1945 | spin_unlock_irq(¤t->sighand->siglock); | |
1946 | ||
1947 | /* signals can be posted during this window */ | |
1948 | ||
1949 | if (is_orphaned_pgrp(process_group(current))) | |
1950 | goto relock; | |
1951 | ||
1952 | spin_lock_irq(¤t->sighand->siglock); | |
1953 | } | |
1954 | ||
1955 | if (likely(do_signal_stop(signr))) { | |
1956 | /* It released the siglock. */ | |
1957 | goto relock; | |
1958 | } | |
1959 | ||
1960 | /* | |
1961 | * We didn't actually stop, due to a race | |
1962 | * with SIGCONT or something like that. | |
1963 | */ | |
1964 | continue; | |
1965 | } | |
1966 | ||
1967 | spin_unlock_irq(¤t->sighand->siglock); | |
1968 | ||
1969 | /* | |
1970 | * Anything else is fatal, maybe with a core dump. | |
1971 | */ | |
1972 | current->flags |= PF_SIGNALED; | |
1973 | if (sig_kernel_coredump(signr)) { | |
1974 | /* | |
1975 | * If it was able to dump core, this kills all | |
1976 | * other threads in the group and synchronizes with | |
1977 | * their demise. If we lost the race with another | |
1978 | * thread getting here, it set group_exit_code | |
1979 | * first and our do_group_exit call below will use | |
1980 | * that value and ignore the one we pass it. | |
1981 | */ | |
1982 | do_coredump((long)signr, signr, regs); | |
1983 | } | |
1984 | ||
1985 | /* | |
1986 | * Death signals, no core dump. | |
1987 | */ | |
1988 | do_group_exit(signr); | |
1989 | /* NOTREACHED */ | |
1990 | } | |
1991 | spin_unlock_irq(¤t->sighand->siglock); | |
1992 | return signr; | |
1993 | } | |
1994 | ||
1da177e4 LT |
1995 | EXPORT_SYMBOL(recalc_sigpending); |
1996 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
1997 | EXPORT_SYMBOL(flush_signals); | |
1998 | EXPORT_SYMBOL(force_sig); | |
1999 | EXPORT_SYMBOL(kill_pg); | |
2000 | EXPORT_SYMBOL(kill_proc); | |
2001 | EXPORT_SYMBOL(ptrace_notify); | |
2002 | EXPORT_SYMBOL(send_sig); | |
2003 | EXPORT_SYMBOL(send_sig_info); | |
2004 | EXPORT_SYMBOL(sigprocmask); | |
2005 | EXPORT_SYMBOL(block_all_signals); | |
2006 | EXPORT_SYMBOL(unblock_all_signals); | |
2007 | ||
2008 | ||
2009 | /* | |
2010 | * System call entry points. | |
2011 | */ | |
2012 | ||
2013 | asmlinkage long sys_restart_syscall(void) | |
2014 | { | |
2015 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2016 | return restart->fn(restart); | |
2017 | } | |
2018 | ||
2019 | long do_no_restart_syscall(struct restart_block *param) | |
2020 | { | |
2021 | return -EINTR; | |
2022 | } | |
2023 | ||
2024 | /* | |
2025 | * We don't need to get the kernel lock - this is all local to this | |
2026 | * particular thread.. (and that's good, because this is _heavily_ | |
2027 | * used by various programs) | |
2028 | */ | |
2029 | ||
2030 | /* | |
2031 | * This is also useful for kernel threads that want to temporarily | |
2032 | * (or permanently) block certain signals. | |
2033 | * | |
2034 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2035 | * interface happily blocks "unblockable" signals like SIGKILL | |
2036 | * and friends. | |
2037 | */ | |
2038 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2039 | { | |
2040 | int error; | |
2041 | sigset_t old_block; | |
2042 | ||
2043 | spin_lock_irq(¤t->sighand->siglock); | |
2044 | old_block = current->blocked; | |
2045 | error = 0; | |
2046 | switch (how) { | |
2047 | case SIG_BLOCK: | |
2048 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2049 | break; | |
2050 | case SIG_UNBLOCK: | |
2051 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2052 | break; | |
2053 | case SIG_SETMASK: | |
2054 | current->blocked = *set; | |
2055 | break; | |
2056 | default: | |
2057 | error = -EINVAL; | |
2058 | } | |
2059 | recalc_sigpending(); | |
2060 | spin_unlock_irq(¤t->sighand->siglock); | |
2061 | if (oldset) | |
2062 | *oldset = old_block; | |
2063 | return error; | |
2064 | } | |
2065 | ||
2066 | asmlinkage long | |
2067 | sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize) | |
2068 | { | |
2069 | int error = -EINVAL; | |
2070 | sigset_t old_set, new_set; | |
2071 | ||
2072 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2073 | if (sigsetsize != sizeof(sigset_t)) | |
2074 | goto out; | |
2075 | ||
2076 | if (set) { | |
2077 | error = -EFAULT; | |
2078 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2079 | goto out; | |
2080 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2081 | ||
2082 | error = sigprocmask(how, &new_set, &old_set); | |
2083 | if (error) | |
2084 | goto out; | |
2085 | if (oset) | |
2086 | goto set_old; | |
2087 | } else if (oset) { | |
2088 | spin_lock_irq(¤t->sighand->siglock); | |
2089 | old_set = current->blocked; | |
2090 | spin_unlock_irq(¤t->sighand->siglock); | |
2091 | ||
2092 | set_old: | |
2093 | error = -EFAULT; | |
2094 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2095 | goto out; | |
2096 | } | |
2097 | error = 0; | |
2098 | out: | |
2099 | return error; | |
2100 | } | |
2101 | ||
2102 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2103 | { | |
2104 | long error = -EINVAL; | |
2105 | sigset_t pending; | |
2106 | ||
2107 | if (sigsetsize > sizeof(sigset_t)) | |
2108 | goto out; | |
2109 | ||
2110 | spin_lock_irq(¤t->sighand->siglock); | |
2111 | sigorsets(&pending, ¤t->pending.signal, | |
2112 | ¤t->signal->shared_pending.signal); | |
2113 | spin_unlock_irq(¤t->sighand->siglock); | |
2114 | ||
2115 | /* Outside the lock because only this thread touches it. */ | |
2116 | sigandsets(&pending, ¤t->blocked, &pending); | |
2117 | ||
2118 | error = -EFAULT; | |
2119 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2120 | error = 0; | |
2121 | ||
2122 | out: | |
2123 | return error; | |
2124 | } | |
2125 | ||
2126 | asmlinkage long | |
2127 | sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize) | |
2128 | { | |
2129 | return do_sigpending(set, sigsetsize); | |
2130 | } | |
2131 | ||
2132 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2133 | ||
2134 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2135 | { | |
2136 | int err; | |
2137 | ||
2138 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2139 | return -EFAULT; | |
2140 | if (from->si_code < 0) | |
2141 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2142 | ? -EFAULT : 0; | |
2143 | /* | |
2144 | * If you change siginfo_t structure, please be sure | |
2145 | * this code is fixed accordingly. | |
2146 | * It should never copy any pad contained in the structure | |
2147 | * to avoid security leaks, but must copy the generic | |
2148 | * 3 ints plus the relevant union member. | |
2149 | */ | |
2150 | err = __put_user(from->si_signo, &to->si_signo); | |
2151 | err |= __put_user(from->si_errno, &to->si_errno); | |
2152 | err |= __put_user((short)from->si_code, &to->si_code); | |
2153 | switch (from->si_code & __SI_MASK) { | |
2154 | case __SI_KILL: | |
2155 | err |= __put_user(from->si_pid, &to->si_pid); | |
2156 | err |= __put_user(from->si_uid, &to->si_uid); | |
2157 | break; | |
2158 | case __SI_TIMER: | |
2159 | err |= __put_user(from->si_tid, &to->si_tid); | |
2160 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2161 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2162 | break; | |
2163 | case __SI_POLL: | |
2164 | err |= __put_user(from->si_band, &to->si_band); | |
2165 | err |= __put_user(from->si_fd, &to->si_fd); | |
2166 | break; | |
2167 | case __SI_FAULT: | |
2168 | err |= __put_user(from->si_addr, &to->si_addr); | |
2169 | #ifdef __ARCH_SI_TRAPNO | |
2170 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
2171 | #endif | |
2172 | break; | |
2173 | case __SI_CHLD: | |
2174 | err |= __put_user(from->si_pid, &to->si_pid); | |
2175 | err |= __put_user(from->si_uid, &to->si_uid); | |
2176 | err |= __put_user(from->si_status, &to->si_status); | |
2177 | err |= __put_user(from->si_utime, &to->si_utime); | |
2178 | err |= __put_user(from->si_stime, &to->si_stime); | |
2179 | break; | |
2180 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2181 | case __SI_MESGQ: /* But this is */ | |
2182 | err |= __put_user(from->si_pid, &to->si_pid); | |
2183 | err |= __put_user(from->si_uid, &to->si_uid); | |
2184 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2185 | break; | |
2186 | default: /* this is just in case for now ... */ | |
2187 | err |= __put_user(from->si_pid, &to->si_pid); | |
2188 | err |= __put_user(from->si_uid, &to->si_uid); | |
2189 | break; | |
2190 | } | |
2191 | return err; | |
2192 | } | |
2193 | ||
2194 | #endif | |
2195 | ||
2196 | asmlinkage long | |
2197 | sys_rt_sigtimedwait(const sigset_t __user *uthese, | |
2198 | siginfo_t __user *uinfo, | |
2199 | const struct timespec __user *uts, | |
2200 | size_t sigsetsize) | |
2201 | { | |
2202 | int ret, sig; | |
2203 | sigset_t these; | |
2204 | struct timespec ts; | |
2205 | siginfo_t info; | |
2206 | long timeout = 0; | |
2207 | ||
2208 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2209 | if (sigsetsize != sizeof(sigset_t)) | |
2210 | return -EINVAL; | |
2211 | ||
2212 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2213 | return -EFAULT; | |
2214 | ||
2215 | /* | |
2216 | * Invert the set of allowed signals to get those we | |
2217 | * want to block. | |
2218 | */ | |
2219 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2220 | signotset(&these); | |
2221 | ||
2222 | if (uts) { | |
2223 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2224 | return -EFAULT; | |
2225 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2226 | || ts.tv_sec < 0) | |
2227 | return -EINVAL; | |
2228 | } | |
2229 | ||
2230 | spin_lock_irq(¤t->sighand->siglock); | |
2231 | sig = dequeue_signal(current, &these, &info); | |
2232 | if (!sig) { | |
2233 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2234 | if (uts) | |
2235 | timeout = (timespec_to_jiffies(&ts) | |
2236 | + (ts.tv_sec || ts.tv_nsec)); | |
2237 | ||
2238 | if (timeout) { | |
2239 | /* None ready -- temporarily unblock those we're | |
2240 | * interested while we are sleeping in so that we'll | |
2241 | * be awakened when they arrive. */ | |
2242 | current->real_blocked = current->blocked; | |
2243 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2244 | recalc_sigpending(); | |
2245 | spin_unlock_irq(¤t->sighand->siglock); | |
2246 | ||
75bcc8c5 | 2247 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2248 | |
3e1d1d28 | 2249 | try_to_freeze(); |
1da177e4 LT |
2250 | spin_lock_irq(¤t->sighand->siglock); |
2251 | sig = dequeue_signal(current, &these, &info); | |
2252 | current->blocked = current->real_blocked; | |
2253 | siginitset(¤t->real_blocked, 0); | |
2254 | recalc_sigpending(); | |
2255 | } | |
2256 | } | |
2257 | spin_unlock_irq(¤t->sighand->siglock); | |
2258 | ||
2259 | if (sig) { | |
2260 | ret = sig; | |
2261 | if (uinfo) { | |
2262 | if (copy_siginfo_to_user(uinfo, &info)) | |
2263 | ret = -EFAULT; | |
2264 | } | |
2265 | } else { | |
2266 | ret = -EAGAIN; | |
2267 | if (timeout) | |
2268 | ret = -EINTR; | |
2269 | } | |
2270 | ||
2271 | return ret; | |
2272 | } | |
2273 | ||
2274 | asmlinkage long | |
2275 | sys_kill(int pid, int sig) | |
2276 | { | |
2277 | struct siginfo info; | |
2278 | ||
2279 | info.si_signo = sig; | |
2280 | info.si_errno = 0; | |
2281 | info.si_code = SI_USER; | |
2282 | info.si_pid = current->tgid; | |
2283 | info.si_uid = current->uid; | |
2284 | ||
2285 | return kill_something_info(sig, &info, pid); | |
2286 | } | |
2287 | ||
2288 | /** | |
2289 | * sys_tgkill - send signal to one specific thread | |
2290 | * @tgid: the thread group ID of the thread | |
2291 | * @pid: the PID of the thread | |
2292 | * @sig: signal to be sent | |
2293 | * | |
2294 | * This syscall also checks the tgid and returns -ESRCH even if the PID | |
2295 | * exists but it's not belonging to the target process anymore. This | |
2296 | * method solves the problem of threads exiting and PIDs getting reused. | |
2297 | */ | |
2298 | asmlinkage long sys_tgkill(int tgid, int pid, int sig) | |
2299 | { | |
2300 | struct siginfo info; | |
2301 | int error; | |
2302 | struct task_struct *p; | |
2303 | ||
2304 | /* This is only valid for single tasks */ | |
2305 | if (pid <= 0 || tgid <= 0) | |
2306 | return -EINVAL; | |
2307 | ||
2308 | info.si_signo = sig; | |
2309 | info.si_errno = 0; | |
2310 | info.si_code = SI_TKILL; | |
2311 | info.si_pid = current->tgid; | |
2312 | info.si_uid = current->uid; | |
2313 | ||
2314 | read_lock(&tasklist_lock); | |
2315 | p = find_task_by_pid(pid); | |
2316 | error = -ESRCH; | |
2317 | if (p && (p->tgid == tgid)) { | |
2318 | error = check_kill_permission(sig, &info, p); | |
2319 | /* | |
2320 | * The null signal is a permissions and process existence | |
2321 | * probe. No signal is actually delivered. | |
2322 | */ | |
2323 | if (!error && sig && p->sighand) { | |
2324 | spin_lock_irq(&p->sighand->siglock); | |
2325 | handle_stop_signal(sig, p); | |
2326 | error = specific_send_sig_info(sig, &info, p); | |
2327 | spin_unlock_irq(&p->sighand->siglock); | |
2328 | } | |
2329 | } | |
2330 | read_unlock(&tasklist_lock); | |
2331 | return error; | |
2332 | } | |
2333 | ||
2334 | /* | |
2335 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2336 | */ | |
2337 | asmlinkage long | |
2338 | sys_tkill(int pid, int sig) | |
2339 | { | |
2340 | struct siginfo info; | |
2341 | int error; | |
2342 | struct task_struct *p; | |
2343 | ||
2344 | /* This is only valid for single tasks */ | |
2345 | if (pid <= 0) | |
2346 | return -EINVAL; | |
2347 | ||
2348 | info.si_signo = sig; | |
2349 | info.si_errno = 0; | |
2350 | info.si_code = SI_TKILL; | |
2351 | info.si_pid = current->tgid; | |
2352 | info.si_uid = current->uid; | |
2353 | ||
2354 | read_lock(&tasklist_lock); | |
2355 | p = find_task_by_pid(pid); | |
2356 | error = -ESRCH; | |
2357 | if (p) { | |
2358 | error = check_kill_permission(sig, &info, p); | |
2359 | /* | |
2360 | * The null signal is a permissions and process existence | |
2361 | * probe. No signal is actually delivered. | |
2362 | */ | |
2363 | if (!error && sig && p->sighand) { | |
2364 | spin_lock_irq(&p->sighand->siglock); | |
2365 | handle_stop_signal(sig, p); | |
2366 | error = specific_send_sig_info(sig, &info, p); | |
2367 | spin_unlock_irq(&p->sighand->siglock); | |
2368 | } | |
2369 | } | |
2370 | read_unlock(&tasklist_lock); | |
2371 | return error; | |
2372 | } | |
2373 | ||
2374 | asmlinkage long | |
2375 | sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) | |
2376 | { | |
2377 | siginfo_t info; | |
2378 | ||
2379 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2380 | return -EFAULT; | |
2381 | ||
2382 | /* Not even root can pretend to send signals from the kernel. | |
2383 | Nor can they impersonate a kill(), which adds source info. */ | |
2384 | if (info.si_code >= 0) | |
2385 | return -EPERM; | |
2386 | info.si_signo = sig; | |
2387 | ||
2388 | /* POSIX.1b doesn't mention process groups. */ | |
2389 | return kill_proc_info(sig, &info, pid); | |
2390 | } | |
2391 | ||
2392 | int | |
2393 | do_sigaction(int sig, const struct k_sigaction *act, struct k_sigaction *oact) | |
2394 | { | |
2395 | struct k_sigaction *k; | |
2396 | ||
7ed20e1a | 2397 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2398 | return -EINVAL; |
2399 | ||
2400 | k = ¤t->sighand->action[sig-1]; | |
2401 | ||
2402 | spin_lock_irq(¤t->sighand->siglock); | |
2403 | if (signal_pending(current)) { | |
2404 | /* | |
2405 | * If there might be a fatal signal pending on multiple | |
2406 | * threads, make sure we take it before changing the action. | |
2407 | */ | |
2408 | spin_unlock_irq(¤t->sighand->siglock); | |
2409 | return -ERESTARTNOINTR; | |
2410 | } | |
2411 | ||
2412 | if (oact) | |
2413 | *oact = *k; | |
2414 | ||
2415 | if (act) { | |
2416 | /* | |
2417 | * POSIX 3.3.1.3: | |
2418 | * "Setting a signal action to SIG_IGN for a signal that is | |
2419 | * pending shall cause the pending signal to be discarded, | |
2420 | * whether or not it is blocked." | |
2421 | * | |
2422 | * "Setting a signal action to SIG_DFL for a signal that is | |
2423 | * pending and whose default action is to ignore the signal | |
2424 | * (for example, SIGCHLD), shall cause the pending signal to | |
2425 | * be discarded, whether or not it is blocked" | |
2426 | */ | |
2427 | if (act->sa.sa_handler == SIG_IGN || | |
2428 | (act->sa.sa_handler == SIG_DFL && | |
2429 | sig_kernel_ignore(sig))) { | |
2430 | /* | |
2431 | * This is a fairly rare case, so we only take the | |
2432 | * tasklist_lock once we're sure we'll need it. | |
2433 | * Now we must do this little unlock and relock | |
2434 | * dance to maintain the lock hierarchy. | |
2435 | */ | |
2436 | struct task_struct *t = current; | |
2437 | spin_unlock_irq(&t->sighand->siglock); | |
2438 | read_lock(&tasklist_lock); | |
2439 | spin_lock_irq(&t->sighand->siglock); | |
2440 | *k = *act; | |
2441 | sigdelsetmask(&k->sa.sa_mask, | |
2442 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2443 | rm_from_queue(sigmask(sig), &t->signal->shared_pending); | |
2444 | do { | |
2445 | rm_from_queue(sigmask(sig), &t->pending); | |
2446 | recalc_sigpending_tsk(t); | |
2447 | t = next_thread(t); | |
2448 | } while (t != current); | |
2449 | spin_unlock_irq(¤t->sighand->siglock); | |
2450 | read_unlock(&tasklist_lock); | |
2451 | return 0; | |
2452 | } | |
2453 | ||
2454 | *k = *act; | |
2455 | sigdelsetmask(&k->sa.sa_mask, | |
2456 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2457 | } | |
2458 | ||
2459 | spin_unlock_irq(¤t->sighand->siglock); | |
2460 | return 0; | |
2461 | } | |
2462 | ||
2463 | int | |
2464 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2465 | { | |
2466 | stack_t oss; | |
2467 | int error; | |
2468 | ||
2469 | if (uoss) { | |
2470 | oss.ss_sp = (void __user *) current->sas_ss_sp; | |
2471 | oss.ss_size = current->sas_ss_size; | |
2472 | oss.ss_flags = sas_ss_flags(sp); | |
2473 | } | |
2474 | ||
2475 | if (uss) { | |
2476 | void __user *ss_sp; | |
2477 | size_t ss_size; | |
2478 | int ss_flags; | |
2479 | ||
2480 | error = -EFAULT; | |
2481 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss)) | |
2482 | || __get_user(ss_sp, &uss->ss_sp) | |
2483 | || __get_user(ss_flags, &uss->ss_flags) | |
2484 | || __get_user(ss_size, &uss->ss_size)) | |
2485 | goto out; | |
2486 | ||
2487 | error = -EPERM; | |
2488 | if (on_sig_stack(sp)) | |
2489 | goto out; | |
2490 | ||
2491 | error = -EINVAL; | |
2492 | /* | |
2493 | * | |
2494 | * Note - this code used to test ss_flags incorrectly | |
2495 | * old code may have been written using ss_flags==0 | |
2496 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2497 | * way that worked) - this fix preserves that older | |
2498 | * mechanism | |
2499 | */ | |
2500 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2501 | goto out; | |
2502 | ||
2503 | if (ss_flags == SS_DISABLE) { | |
2504 | ss_size = 0; | |
2505 | ss_sp = NULL; | |
2506 | } else { | |
2507 | error = -ENOMEM; | |
2508 | if (ss_size < MINSIGSTKSZ) | |
2509 | goto out; | |
2510 | } | |
2511 | ||
2512 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2513 | current->sas_ss_size = ss_size; | |
2514 | } | |
2515 | ||
2516 | if (uoss) { | |
2517 | error = -EFAULT; | |
2518 | if (copy_to_user(uoss, &oss, sizeof(oss))) | |
2519 | goto out; | |
2520 | } | |
2521 | ||
2522 | error = 0; | |
2523 | out: | |
2524 | return error; | |
2525 | } | |
2526 | ||
2527 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2528 | ||
2529 | asmlinkage long | |
2530 | sys_sigpending(old_sigset_t __user *set) | |
2531 | { | |
2532 | return do_sigpending(set, sizeof(*set)); | |
2533 | } | |
2534 | ||
2535 | #endif | |
2536 | ||
2537 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2538 | /* Some platforms have their own version with special arguments others | |
2539 | support only sys_rt_sigprocmask. */ | |
2540 | ||
2541 | asmlinkage long | |
2542 | sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset) | |
2543 | { | |
2544 | int error; | |
2545 | old_sigset_t old_set, new_set; | |
2546 | ||
2547 | if (set) { | |
2548 | error = -EFAULT; | |
2549 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2550 | goto out; | |
2551 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2552 | ||
2553 | spin_lock_irq(¤t->sighand->siglock); | |
2554 | old_set = current->blocked.sig[0]; | |
2555 | ||
2556 | error = 0; | |
2557 | switch (how) { | |
2558 | default: | |
2559 | error = -EINVAL; | |
2560 | break; | |
2561 | case SIG_BLOCK: | |
2562 | sigaddsetmask(¤t->blocked, new_set); | |
2563 | break; | |
2564 | case SIG_UNBLOCK: | |
2565 | sigdelsetmask(¤t->blocked, new_set); | |
2566 | break; | |
2567 | case SIG_SETMASK: | |
2568 | current->blocked.sig[0] = new_set; | |
2569 | break; | |
2570 | } | |
2571 | ||
2572 | recalc_sigpending(); | |
2573 | spin_unlock_irq(¤t->sighand->siglock); | |
2574 | if (error) | |
2575 | goto out; | |
2576 | if (oset) | |
2577 | goto set_old; | |
2578 | } else if (oset) { | |
2579 | old_set = current->blocked.sig[0]; | |
2580 | set_old: | |
2581 | error = -EFAULT; | |
2582 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2583 | goto out; | |
2584 | } | |
2585 | error = 0; | |
2586 | out: | |
2587 | return error; | |
2588 | } | |
2589 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2590 | ||
2591 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
2592 | asmlinkage long | |
2593 | sys_rt_sigaction(int sig, | |
2594 | const struct sigaction __user *act, | |
2595 | struct sigaction __user *oact, | |
2596 | size_t sigsetsize) | |
2597 | { | |
2598 | struct k_sigaction new_sa, old_sa; | |
2599 | int ret = -EINVAL; | |
2600 | ||
2601 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2602 | if (sigsetsize != sizeof(sigset_t)) | |
2603 | goto out; | |
2604 | ||
2605 | if (act) { | |
2606 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2607 | return -EFAULT; | |
2608 | } | |
2609 | ||
2610 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2611 | ||
2612 | if (!ret && oact) { | |
2613 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2614 | return -EFAULT; | |
2615 | } | |
2616 | out: | |
2617 | return ret; | |
2618 | } | |
2619 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2620 | ||
2621 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2622 | ||
2623 | /* | |
2624 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2625 | */ | |
2626 | asmlinkage long | |
2627 | sys_sgetmask(void) | |
2628 | { | |
2629 | /* SMP safe */ | |
2630 | return current->blocked.sig[0]; | |
2631 | } | |
2632 | ||
2633 | asmlinkage long | |
2634 | sys_ssetmask(int newmask) | |
2635 | { | |
2636 | int old; | |
2637 | ||
2638 | spin_lock_irq(¤t->sighand->siglock); | |
2639 | old = current->blocked.sig[0]; | |
2640 | ||
2641 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2642 | sigmask(SIGSTOP))); | |
2643 | recalc_sigpending(); | |
2644 | spin_unlock_irq(¤t->sighand->siglock); | |
2645 | ||
2646 | return old; | |
2647 | } | |
2648 | #endif /* __ARCH_WANT_SGETMASK */ | |
2649 | ||
2650 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2651 | /* | |
2652 | * For backwards compatibility. Functionality superseded by sigaction. | |
2653 | */ | |
2654 | asmlinkage unsigned long | |
2655 | sys_signal(int sig, __sighandler_t handler) | |
2656 | { | |
2657 | struct k_sigaction new_sa, old_sa; | |
2658 | int ret; | |
2659 | ||
2660 | new_sa.sa.sa_handler = handler; | |
2661 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
2662 | ||
2663 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2664 | ||
2665 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2666 | } | |
2667 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2668 | ||
2669 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2670 | ||
2671 | asmlinkage long | |
2672 | sys_pause(void) | |
2673 | { | |
2674 | current->state = TASK_INTERRUPTIBLE; | |
2675 | schedule(); | |
2676 | return -ERESTARTNOHAND; | |
2677 | } | |
2678 | ||
2679 | #endif | |
2680 | ||
2681 | void __init signals_init(void) | |
2682 | { | |
2683 | sigqueue_cachep = | |
2684 | kmem_cache_create("sigqueue", | |
2685 | sizeof(struct sigqueue), | |
2686 | __alignof__(struct sigqueue), | |
2687 | SLAB_PANIC, NULL, NULL); | |
2688 | } |