Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 | 13 | #include <linux/slab.h> |
9984de1a | 14 | #include <linux/export.h> |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
179899fd | 20 | #include <linux/coredump.h> |
1da177e4 LT |
21 | #include <linux/security.h> |
22 | #include <linux/syscalls.h> | |
23 | #include <linux/ptrace.h> | |
7ed20e1a | 24 | #include <linux/signal.h> |
fba2afaa | 25 | #include <linux/signalfd.h> |
f84d49b2 | 26 | #include <linux/ratelimit.h> |
35de254d | 27 | #include <linux/tracehook.h> |
c59ede7b | 28 | #include <linux/capability.h> |
7dfb7103 | 29 | #include <linux/freezer.h> |
84d73786 SB |
30 | #include <linux/pid_namespace.h> |
31 | #include <linux/nsproxy.h> | |
6b550f94 | 32 | #include <linux/user_namespace.h> |
0326f5a9 | 33 | #include <linux/uprobes.h> |
90268439 | 34 | #include <linux/compat.h> |
2b5faa4c | 35 | #include <linux/cn_proc.h> |
d1eb650f MH |
36 | #define CREATE_TRACE_POINTS |
37 | #include <trace/events/signal.h> | |
84d73786 | 38 | |
1da177e4 LT |
39 | #include <asm/param.h> |
40 | #include <asm/uaccess.h> | |
41 | #include <asm/unistd.h> | |
42 | #include <asm/siginfo.h> | |
d550bbd4 | 43 | #include <asm/cacheflush.h> |
e1396065 | 44 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
45 | |
46 | /* | |
47 | * SLAB caches for signal bits. | |
48 | */ | |
49 | ||
e18b890b | 50 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 51 | |
f84d49b2 NO |
52 | int print_fatal_signals __read_mostly; |
53 | ||
35de254d | 54 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 55 | { |
35de254d RM |
56 | return t->sighand->action[sig - 1].sa.sa_handler; |
57 | } | |
93585eea | 58 | |
35de254d RM |
59 | static int sig_handler_ignored(void __user *handler, int sig) |
60 | { | |
93585eea | 61 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
62 | return handler == SIG_IGN || |
63 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
64 | } | |
1da177e4 | 65 | |
def8cf72 | 66 | static int sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 67 | { |
35de254d | 68 | void __user *handler; |
1da177e4 | 69 | |
f008faff ON |
70 | handler = sig_handler(t, sig); |
71 | ||
72 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
def8cf72 | 73 | handler == SIG_DFL && !force) |
f008faff ON |
74 | return 1; |
75 | ||
76 | return sig_handler_ignored(handler, sig); | |
77 | } | |
78 | ||
def8cf72 | 79 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 80 | { |
1da177e4 LT |
81 | /* |
82 | * Blocked signals are never ignored, since the | |
83 | * signal handler may change by the time it is | |
84 | * unblocked. | |
85 | */ | |
325d22df | 86 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
87 | return 0; |
88 | ||
def8cf72 | 89 | if (!sig_task_ignored(t, sig, force)) |
35de254d RM |
90 | return 0; |
91 | ||
92 | /* | |
93 | * Tracers may want to know about even ignored signals. | |
94 | */ | |
a288eecc | 95 | return !t->ptrace; |
1da177e4 LT |
96 | } |
97 | ||
98 | /* | |
99 | * Re-calculate pending state from the set of locally pending | |
100 | * signals, globally pending signals, and blocked signals. | |
101 | */ | |
102 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
103 | { | |
104 | unsigned long ready; | |
105 | long i; | |
106 | ||
107 | switch (_NSIG_WORDS) { | |
108 | default: | |
109 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
110 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
111 | break; | |
112 | ||
113 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
114 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
115 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
116 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
117 | break; | |
118 | ||
119 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
120 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
121 | break; | |
122 | ||
123 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
124 | } | |
125 | return ready != 0; | |
126 | } | |
127 | ||
128 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
129 | ||
7bb44ade | 130 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 131 | { |
3759a0d9 | 132 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 133 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 134 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 135 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
136 | return 1; |
137 | } | |
b74d0deb RM |
138 | /* |
139 | * We must never clear the flag in another thread, or in current | |
140 | * when it's possible the current syscall is returning -ERESTART*. | |
141 | * So we don't clear it here, and only callers who know they should do. | |
142 | */ | |
7bb44ade RM |
143 | return 0; |
144 | } | |
145 | ||
146 | /* | |
147 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
148 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
149 | */ | |
150 | void recalc_sigpending_and_wake(struct task_struct *t) | |
151 | { | |
152 | if (recalc_sigpending_tsk(t)) | |
153 | signal_wake_up(t, 0); | |
1da177e4 LT |
154 | } |
155 | ||
156 | void recalc_sigpending(void) | |
157 | { | |
dd1d6772 | 158 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
159 | clear_thread_flag(TIF_SIGPENDING); |
160 | ||
1da177e4 LT |
161 | } |
162 | ||
163 | /* Given the mask, find the first available signal that should be serviced. */ | |
164 | ||
a27341cd LT |
165 | #define SYNCHRONOUS_MASK \ |
166 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 167 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 168 | |
fba2afaa | 169 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
170 | { |
171 | unsigned long i, *s, *m, x; | |
172 | int sig = 0; | |
f84d49b2 | 173 | |
1da177e4 LT |
174 | s = pending->signal.sig; |
175 | m = mask->sig; | |
a27341cd LT |
176 | |
177 | /* | |
178 | * Handle the first word specially: it contains the | |
179 | * synchronous signals that need to be dequeued first. | |
180 | */ | |
181 | x = *s &~ *m; | |
182 | if (x) { | |
183 | if (x & SYNCHRONOUS_MASK) | |
184 | x &= SYNCHRONOUS_MASK; | |
185 | sig = ffz(~x) + 1; | |
186 | return sig; | |
187 | } | |
188 | ||
1da177e4 LT |
189 | switch (_NSIG_WORDS) { |
190 | default: | |
a27341cd LT |
191 | for (i = 1; i < _NSIG_WORDS; ++i) { |
192 | x = *++s &~ *++m; | |
193 | if (!x) | |
194 | continue; | |
195 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
196 | break; | |
197 | } | |
1da177e4 LT |
198 | break; |
199 | ||
a27341cd LT |
200 | case 2: |
201 | x = s[1] &~ m[1]; | |
202 | if (!x) | |
1da177e4 | 203 | break; |
a27341cd | 204 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
205 | break; |
206 | ||
a27341cd LT |
207 | case 1: |
208 | /* Nothing to do */ | |
1da177e4 LT |
209 | break; |
210 | } | |
f84d49b2 | 211 | |
1da177e4 LT |
212 | return sig; |
213 | } | |
214 | ||
f84d49b2 NO |
215 | static inline void print_dropped_signal(int sig) |
216 | { | |
217 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
218 | ||
219 | if (!print_fatal_signals) | |
220 | return; | |
221 | ||
222 | if (!__ratelimit(&ratelimit_state)) | |
223 | return; | |
224 | ||
225 | printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", | |
226 | current->comm, current->pid, sig); | |
227 | } | |
228 | ||
d79fdd6d | 229 | /** |
7dd3db54 | 230 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 231 | * @task: target task |
7dd3db54 | 232 | * @mask: pending bits to set |
d79fdd6d | 233 | * |
7dd3db54 TH |
234 | * Clear @mask from @task->jobctl. @mask must be subset of |
235 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
236 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
237 | * cleared. If @task is already being killed or exiting, this function | |
238 | * becomes noop. | |
239 | * | |
240 | * CONTEXT: | |
241 | * Must be called with @task->sighand->siglock held. | |
242 | * | |
243 | * RETURNS: | |
244 | * %true if @mask is set, %false if made noop because @task was dying. | |
245 | */ | |
246 | bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask) | |
247 | { | |
248 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
249 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
250 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
251 | ||
252 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
253 | return false; | |
254 | ||
255 | if (mask & JOBCTL_STOP_SIGMASK) | |
256 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
257 | ||
258 | task->jobctl |= mask; | |
259 | return true; | |
260 | } | |
261 | ||
d79fdd6d | 262 | /** |
a8f072c1 | 263 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
264 | * @task: target task |
265 | * | |
a8f072c1 TH |
266 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
267 | * Clear it and wake up the ptracer. Note that we don't need any further | |
268 | * locking. @task->siglock guarantees that @task->parent points to the | |
269 | * ptracer. | |
d79fdd6d TH |
270 | * |
271 | * CONTEXT: | |
272 | * Must be called with @task->sighand->siglock held. | |
273 | */ | |
73ddff2b | 274 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 275 | { |
a8f072c1 TH |
276 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
277 | task->jobctl &= ~JOBCTL_TRAPPING; | |
62c124ff | 278 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
279 | } |
280 | } | |
281 | ||
e5c1902e | 282 | /** |
3759a0d9 | 283 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 284 | * @task: target task |
3759a0d9 | 285 | * @mask: pending bits to clear |
e5c1902e | 286 | * |
3759a0d9 TH |
287 | * Clear @mask from @task->jobctl. @mask must be subset of |
288 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
289 | * STOP bits are cleared together. | |
e5c1902e | 290 | * |
6dfca329 TH |
291 | * If clearing of @mask leaves no stop or trap pending, this function calls |
292 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
293 | * |
294 | * CONTEXT: | |
295 | * Must be called with @task->sighand->siglock held. | |
296 | */ | |
3759a0d9 | 297 | void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask) |
e5c1902e | 298 | { |
3759a0d9 TH |
299 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
300 | ||
301 | if (mask & JOBCTL_STOP_PENDING) | |
302 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
303 | ||
304 | task->jobctl &= ~mask; | |
6dfca329 TH |
305 | |
306 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
307 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
308 | } |
309 | ||
310 | /** | |
311 | * task_participate_group_stop - participate in a group stop | |
312 | * @task: task participating in a group stop | |
313 | * | |
a8f072c1 | 314 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 315 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 316 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 317 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
318 | * |
319 | * CONTEXT: | |
320 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
321 | * |
322 | * RETURNS: | |
323 | * %true if group stop completion should be notified to the parent, %false | |
324 | * otherwise. | |
e5c1902e TH |
325 | */ |
326 | static bool task_participate_group_stop(struct task_struct *task) | |
327 | { | |
328 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 329 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 330 | |
a8f072c1 | 331 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 332 | |
3759a0d9 | 333 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
334 | |
335 | if (!consume) | |
336 | return false; | |
337 | ||
338 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
339 | sig->group_stop_count--; | |
340 | ||
244056f9 TH |
341 | /* |
342 | * Tell the caller to notify completion iff we are entering into a | |
343 | * fresh group stop. Read comment in do_signal_stop() for details. | |
344 | */ | |
345 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
e5c1902e TH |
346 | sig->flags = SIGNAL_STOP_STOPPED; |
347 | return true; | |
348 | } | |
349 | return false; | |
350 | } | |
351 | ||
c69e8d9c DH |
352 | /* |
353 | * allocate a new signal queue record | |
354 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 355 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 356 | */ |
f84d49b2 NO |
357 | static struct sigqueue * |
358 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
359 | { |
360 | struct sigqueue *q = NULL; | |
10b1fbdb | 361 | struct user_struct *user; |
1da177e4 | 362 | |
10b1fbdb | 363 | /* |
7cf7db8d TG |
364 | * Protect access to @t credentials. This can go away when all |
365 | * callers hold rcu read lock. | |
10b1fbdb | 366 | */ |
7cf7db8d | 367 | rcu_read_lock(); |
d84f4f99 | 368 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 369 | atomic_inc(&user->sigpending); |
7cf7db8d | 370 | rcu_read_unlock(); |
f84d49b2 | 371 | |
1da177e4 | 372 | if (override_rlimit || |
10b1fbdb | 373 | atomic_read(&user->sigpending) <= |
78d7d407 | 374 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 375 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
376 | } else { |
377 | print_dropped_signal(sig); | |
378 | } | |
379 | ||
1da177e4 | 380 | if (unlikely(q == NULL)) { |
10b1fbdb | 381 | atomic_dec(&user->sigpending); |
d84f4f99 | 382 | free_uid(user); |
1da177e4 LT |
383 | } else { |
384 | INIT_LIST_HEAD(&q->list); | |
385 | q->flags = 0; | |
d84f4f99 | 386 | q->user = user; |
1da177e4 | 387 | } |
d84f4f99 DH |
388 | |
389 | return q; | |
1da177e4 LT |
390 | } |
391 | ||
514a01b8 | 392 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
393 | { |
394 | if (q->flags & SIGQUEUE_PREALLOC) | |
395 | return; | |
396 | atomic_dec(&q->user->sigpending); | |
397 | free_uid(q->user); | |
398 | kmem_cache_free(sigqueue_cachep, q); | |
399 | } | |
400 | ||
6a14c5c9 | 401 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
402 | { |
403 | struct sigqueue *q; | |
404 | ||
405 | sigemptyset(&queue->signal); | |
406 | while (!list_empty(&queue->list)) { | |
407 | q = list_entry(queue->list.next, struct sigqueue , list); | |
408 | list_del_init(&q->list); | |
409 | __sigqueue_free(q); | |
410 | } | |
411 | } | |
412 | ||
413 | /* | |
414 | * Flush all pending signals for a task. | |
415 | */ | |
3bcac026 DH |
416 | void __flush_signals(struct task_struct *t) |
417 | { | |
418 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
419 | flush_sigqueue(&t->pending); | |
420 | flush_sigqueue(&t->signal->shared_pending); | |
421 | } | |
422 | ||
c81addc9 | 423 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
424 | { |
425 | unsigned long flags; | |
426 | ||
427 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
3bcac026 | 428 | __flush_signals(t); |
1da177e4 LT |
429 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
430 | } | |
431 | ||
cbaffba1 ON |
432 | static void __flush_itimer_signals(struct sigpending *pending) |
433 | { | |
434 | sigset_t signal, retain; | |
435 | struct sigqueue *q, *n; | |
436 | ||
437 | signal = pending->signal; | |
438 | sigemptyset(&retain); | |
439 | ||
440 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
441 | int sig = q->info.si_signo; | |
442 | ||
443 | if (likely(q->info.si_code != SI_TIMER)) { | |
444 | sigaddset(&retain, sig); | |
445 | } else { | |
446 | sigdelset(&signal, sig); | |
447 | list_del_init(&q->list); | |
448 | __sigqueue_free(q); | |
449 | } | |
450 | } | |
451 | ||
452 | sigorsets(&pending->signal, &signal, &retain); | |
453 | } | |
454 | ||
455 | void flush_itimer_signals(void) | |
456 | { | |
457 | struct task_struct *tsk = current; | |
458 | unsigned long flags; | |
459 | ||
460 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
461 | __flush_itimer_signals(&tsk->pending); | |
462 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
463 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
464 | } | |
465 | ||
10ab825b ON |
466 | void ignore_signals(struct task_struct *t) |
467 | { | |
468 | int i; | |
469 | ||
470 | for (i = 0; i < _NSIG; ++i) | |
471 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
472 | ||
473 | flush_signals(t); | |
474 | } | |
475 | ||
1da177e4 LT |
476 | /* |
477 | * Flush all handlers for a task. | |
478 | */ | |
479 | ||
480 | void | |
481 | flush_signal_handlers(struct task_struct *t, int force_default) | |
482 | { | |
483 | int i; | |
484 | struct k_sigaction *ka = &t->sighand->action[0]; | |
485 | for (i = _NSIG ; i != 0 ; i--) { | |
486 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
487 | ka->sa.sa_handler = SIG_DFL; | |
488 | ka->sa.sa_flags = 0; | |
522cff14 | 489 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
490 | ka->sa.sa_restorer = NULL; |
491 | #endif | |
1da177e4 LT |
492 | sigemptyset(&ka->sa.sa_mask); |
493 | ka++; | |
494 | } | |
495 | } | |
496 | ||
abd4f750 MAS |
497 | int unhandled_signal(struct task_struct *tsk, int sig) |
498 | { | |
445a91d2 | 499 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 500 | if (is_global_init(tsk)) |
abd4f750 | 501 | return 1; |
445a91d2 | 502 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 503 | return 0; |
a288eecc TH |
504 | /* if ptraced, let the tracer determine */ |
505 | return !tsk->ptrace; | |
abd4f750 MAS |
506 | } |
507 | ||
5aba085e RD |
508 | /* |
509 | * Notify the system that a driver wants to block all signals for this | |
1da177e4 LT |
510 | * process, and wants to be notified if any signals at all were to be |
511 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
512 | * signal will be acted upon after all. If the notifier routine returns 0, | |
513 | * then then signal will be blocked. Only one block per process is | |
514 | * allowed. priv is a pointer to private data that the notifier routine | |
5aba085e RD |
515 | * can use to determine if the signal should be blocked or not. |
516 | */ | |
1da177e4 LT |
517 | void |
518 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
519 | { | |
520 | unsigned long flags; | |
521 | ||
522 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
523 | current->notifier_mask = mask; | |
524 | current->notifier_data = priv; | |
525 | current->notifier = notifier; | |
526 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
527 | } | |
528 | ||
529 | /* Notify the system that blocking has ended. */ | |
530 | ||
531 | void | |
532 | unblock_all_signals(void) | |
533 | { | |
534 | unsigned long flags; | |
535 | ||
536 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
537 | current->notifier = NULL; | |
538 | current->notifier_data = NULL; | |
539 | recalc_sigpending(); | |
540 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
541 | } | |
542 | ||
100360f0 | 543 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
544 | { |
545 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 546 | |
1da177e4 LT |
547 | /* |
548 | * Collect the siginfo appropriate to this signal. Check if | |
549 | * there is another siginfo for the same signal. | |
550 | */ | |
551 | list_for_each_entry(q, &list->list, list) { | |
552 | if (q->info.si_signo == sig) { | |
d4434207 ON |
553 | if (first) |
554 | goto still_pending; | |
1da177e4 LT |
555 | first = q; |
556 | } | |
557 | } | |
d4434207 ON |
558 | |
559 | sigdelset(&list->signal, sig); | |
560 | ||
1da177e4 | 561 | if (first) { |
d4434207 | 562 | still_pending: |
1da177e4 LT |
563 | list_del_init(&first->list); |
564 | copy_siginfo(info, &first->info); | |
565 | __sigqueue_free(first); | |
1da177e4 | 566 | } else { |
5aba085e RD |
567 | /* |
568 | * Ok, it wasn't in the queue. This must be | |
569 | * a fast-pathed signal or we must have been | |
570 | * out of queue space. So zero out the info. | |
1da177e4 | 571 | */ |
1da177e4 LT |
572 | info->si_signo = sig; |
573 | info->si_errno = 0; | |
7486e5d9 | 574 | info->si_code = SI_USER; |
1da177e4 LT |
575 | info->si_pid = 0; |
576 | info->si_uid = 0; | |
577 | } | |
1da177e4 LT |
578 | } |
579 | ||
580 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
581 | siginfo_t *info) | |
582 | { | |
27d91e07 | 583 | int sig = next_signal(pending, mask); |
1da177e4 | 584 | |
1da177e4 LT |
585 | if (sig) { |
586 | if (current->notifier) { | |
587 | if (sigismember(current->notifier_mask, sig)) { | |
588 | if (!(current->notifier)(current->notifier_data)) { | |
589 | clear_thread_flag(TIF_SIGPENDING); | |
590 | return 0; | |
591 | } | |
592 | } | |
593 | } | |
594 | ||
100360f0 | 595 | collect_signal(sig, pending, info); |
1da177e4 | 596 | } |
1da177e4 LT |
597 | |
598 | return sig; | |
599 | } | |
600 | ||
601 | /* | |
5aba085e | 602 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
603 | * expected to free it. |
604 | * | |
605 | * All callers have to hold the siglock. | |
606 | */ | |
607 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
608 | { | |
c5363d03 | 609 | int signr; |
caec4e8d BH |
610 | |
611 | /* We only dequeue private signals from ourselves, we don't let | |
612 | * signalfd steal them | |
613 | */ | |
b8fceee1 | 614 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 615 | if (!signr) { |
1da177e4 LT |
616 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
617 | mask, info); | |
8bfd9a7a TG |
618 | /* |
619 | * itimer signal ? | |
620 | * | |
621 | * itimers are process shared and we restart periodic | |
622 | * itimers in the signal delivery path to prevent DoS | |
623 | * attacks in the high resolution timer case. This is | |
5aba085e | 624 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
625 | * itimers, as the SIGALRM is a legacy signal and only |
626 | * queued once. Changing the restart behaviour to | |
627 | * restart the timer in the signal dequeue path is | |
628 | * reducing the timer noise on heavy loaded !highres | |
629 | * systems too. | |
630 | */ | |
631 | if (unlikely(signr == SIGALRM)) { | |
632 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
633 | ||
634 | if (!hrtimer_is_queued(tmr) && | |
635 | tsk->signal->it_real_incr.tv64 != 0) { | |
636 | hrtimer_forward(tmr, tmr->base->get_time(), | |
637 | tsk->signal->it_real_incr); | |
638 | hrtimer_restart(tmr); | |
639 | } | |
640 | } | |
641 | } | |
c5363d03 | 642 | |
b8fceee1 | 643 | recalc_sigpending(); |
c5363d03 PE |
644 | if (!signr) |
645 | return 0; | |
646 | ||
647 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
648 | /* |
649 | * Set a marker that we have dequeued a stop signal. Our | |
650 | * caller might release the siglock and then the pending | |
651 | * stop signal it is about to process is no longer in the | |
652 | * pending bitmasks, but must still be cleared by a SIGCONT | |
653 | * (and overruled by a SIGKILL). So those cases clear this | |
654 | * shared flag after we've set it. Note that this flag may | |
655 | * remain set after the signal we return is ignored or | |
656 | * handled. That doesn't matter because its only purpose | |
657 | * is to alert stop-signal processing code when another | |
658 | * processor has come along and cleared the flag. | |
659 | */ | |
a8f072c1 | 660 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 661 | } |
c5363d03 | 662 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
663 | /* |
664 | * Release the siglock to ensure proper locking order | |
665 | * of timer locks outside of siglocks. Note, we leave | |
666 | * irqs disabled here, since the posix-timers code is | |
667 | * about to disable them again anyway. | |
668 | */ | |
669 | spin_unlock(&tsk->sighand->siglock); | |
670 | do_schedule_next_timer(info); | |
671 | spin_lock(&tsk->sighand->siglock); | |
672 | } | |
673 | return signr; | |
674 | } | |
675 | ||
676 | /* | |
677 | * Tell a process that it has a new active signal.. | |
678 | * | |
679 | * NOTE! we rely on the previous spin_lock to | |
680 | * lock interrupts for us! We can only be called with | |
681 | * "siglock" held, and the local interrupt must | |
682 | * have been disabled when that got acquired! | |
683 | * | |
684 | * No need to set need_resched since signal event passing | |
685 | * goes through ->blocked | |
686 | */ | |
910ffdb1 | 687 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 688 | { |
1da177e4 | 689 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 690 | /* |
910ffdb1 | 691 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 692 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
693 | * executing another processor and just now entering stopped state. |
694 | * By using wake_up_state, we ensure the process will wake up and | |
695 | * handle its death signal. | |
696 | */ | |
910ffdb1 | 697 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
698 | kick_process(t); |
699 | } | |
700 | ||
71fabd5e GA |
701 | /* |
702 | * Remove signals in mask from the pending set and queue. | |
703 | * Returns 1 if any signals were found. | |
704 | * | |
705 | * All callers must be holding the siglock. | |
706 | * | |
707 | * This version takes a sigset mask and looks at all signals, | |
708 | * not just those in the first mask word. | |
709 | */ | |
710 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
711 | { | |
712 | struct sigqueue *q, *n; | |
713 | sigset_t m; | |
714 | ||
715 | sigandsets(&m, mask, &s->signal); | |
716 | if (sigisemptyset(&m)) | |
717 | return 0; | |
718 | ||
702a5073 | 719 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
720 | list_for_each_entry_safe(q, n, &s->list, list) { |
721 | if (sigismember(mask, q->info.si_signo)) { | |
722 | list_del_init(&q->list); | |
723 | __sigqueue_free(q); | |
724 | } | |
725 | } | |
726 | return 1; | |
727 | } | |
1da177e4 LT |
728 | /* |
729 | * Remove signals in mask from the pending set and queue. | |
730 | * Returns 1 if any signals were found. | |
731 | * | |
732 | * All callers must be holding the siglock. | |
733 | */ | |
734 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
735 | { | |
736 | struct sigqueue *q, *n; | |
737 | ||
738 | if (!sigtestsetmask(&s->signal, mask)) | |
739 | return 0; | |
740 | ||
741 | sigdelsetmask(&s->signal, mask); | |
742 | list_for_each_entry_safe(q, n, &s->list, list) { | |
743 | if (q->info.si_signo < SIGRTMIN && | |
744 | (mask & sigmask(q->info.si_signo))) { | |
745 | list_del_init(&q->list); | |
746 | __sigqueue_free(q); | |
747 | } | |
748 | } | |
749 | return 1; | |
750 | } | |
751 | ||
614c517d ON |
752 | static inline int is_si_special(const struct siginfo *info) |
753 | { | |
754 | return info <= SEND_SIG_FORCED; | |
755 | } | |
756 | ||
757 | static inline bool si_fromuser(const struct siginfo *info) | |
758 | { | |
759 | return info == SEND_SIG_NOINFO || | |
760 | (!is_si_special(info) && SI_FROMUSER(info)); | |
761 | } | |
762 | ||
39fd3393 SH |
763 | /* |
764 | * called with RCU read lock from check_kill_permission() | |
765 | */ | |
766 | static int kill_ok_by_cred(struct task_struct *t) | |
767 | { | |
768 | const struct cred *cred = current_cred(); | |
769 | const struct cred *tcred = __task_cred(t); | |
770 | ||
5af66203 EB |
771 | if (uid_eq(cred->euid, tcred->suid) || |
772 | uid_eq(cred->euid, tcred->uid) || | |
773 | uid_eq(cred->uid, tcred->suid) || | |
774 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
775 | return 1; |
776 | ||
c4a4d603 | 777 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
778 | return 1; |
779 | ||
780 | return 0; | |
781 | } | |
782 | ||
1da177e4 LT |
783 | /* |
784 | * Bad permissions for sending the signal | |
694f690d | 785 | * - the caller must hold the RCU read lock |
1da177e4 LT |
786 | */ |
787 | static int check_kill_permission(int sig, struct siginfo *info, | |
788 | struct task_struct *t) | |
789 | { | |
2e2ba22e | 790 | struct pid *sid; |
3b5e9e53 ON |
791 | int error; |
792 | ||
7ed20e1a | 793 | if (!valid_signal(sig)) |
3b5e9e53 ON |
794 | return -EINVAL; |
795 | ||
614c517d | 796 | if (!si_fromuser(info)) |
3b5e9e53 | 797 | return 0; |
e54dc243 | 798 | |
3b5e9e53 ON |
799 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
800 | if (error) | |
1da177e4 | 801 | return error; |
3b5e9e53 | 802 | |
065add39 | 803 | if (!same_thread_group(current, t) && |
39fd3393 | 804 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
805 | switch (sig) { |
806 | case SIGCONT: | |
2e2ba22e | 807 | sid = task_session(t); |
2e2ba22e ON |
808 | /* |
809 | * We don't return the error if sid == NULL. The | |
810 | * task was unhashed, the caller must notice this. | |
811 | */ | |
812 | if (!sid || sid == task_session(current)) | |
813 | break; | |
814 | default: | |
815 | return -EPERM; | |
816 | } | |
817 | } | |
c2f0c7c3 | 818 | |
e54dc243 | 819 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
820 | } |
821 | ||
fb1d910c TH |
822 | /** |
823 | * ptrace_trap_notify - schedule trap to notify ptracer | |
824 | * @t: tracee wanting to notify tracer | |
825 | * | |
826 | * This function schedules sticky ptrace trap which is cleared on the next | |
827 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
828 | * ptracer. | |
829 | * | |
544b2c91 TH |
830 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
831 | * ptracer is listening for events, tracee is woken up so that it can | |
832 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
833 | * eventually taken without returning to userland after the existing traps | |
834 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
835 | * |
836 | * CONTEXT: | |
837 | * Must be called with @task->sighand->siglock held. | |
838 | */ | |
839 | static void ptrace_trap_notify(struct task_struct *t) | |
840 | { | |
841 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
842 | assert_spin_locked(&t->sighand->siglock); | |
843 | ||
844 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 845 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
846 | } |
847 | ||
1da177e4 | 848 | /* |
7e695a5e ON |
849 | * Handle magic process-wide effects of stop/continue signals. Unlike |
850 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
851 | * time regardless of blocking, ignoring, or handling. This does the |
852 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
853 | * signals. The process stop is done as a signal action for SIG_DFL. |
854 | * | |
855 | * Returns true if the signal should be actually delivered, otherwise | |
856 | * it should be dropped. | |
1da177e4 | 857 | */ |
def8cf72 | 858 | static int prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 859 | { |
ad16a460 | 860 | struct signal_struct *signal = p->signal; |
1da177e4 LT |
861 | struct task_struct *t; |
862 | ||
7e695a5e | 863 | if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) { |
1da177e4 | 864 | /* |
7e695a5e | 865 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 866 | */ |
7e695a5e | 867 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
868 | /* |
869 | * This is a stop signal. Remove SIGCONT from all queues. | |
870 | */ | |
ad16a460 | 871 | rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); |
1da177e4 LT |
872 | t = p; |
873 | do { | |
874 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
ad16a460 | 875 | } while_each_thread(p, t); |
1da177e4 | 876 | } else if (sig == SIGCONT) { |
fc321d2e | 877 | unsigned int why; |
1da177e4 | 878 | /* |
1deac632 | 879 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 880 | */ |
ad16a460 | 881 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
882 | t = p; |
883 | do { | |
3759a0d9 | 884 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
1da177e4 | 885 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); |
fb1d910c TH |
886 | if (likely(!(t->ptrace & PT_SEIZED))) |
887 | wake_up_state(t, __TASK_STOPPED); | |
888 | else | |
889 | ptrace_trap_notify(t); | |
ad16a460 | 890 | } while_each_thread(p, t); |
1da177e4 | 891 | |
fc321d2e ON |
892 | /* |
893 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
894 | * | |
895 | * If we were in the middle of a group stop, we pretend it | |
896 | * was already finished, and then continued. Since SIGCHLD | |
897 | * doesn't queue we report only CLD_STOPPED, as if the next | |
898 | * CLD_CONTINUED was dropped. | |
899 | */ | |
900 | why = 0; | |
ad16a460 | 901 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 902 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 903 | else if (signal->group_stop_count) |
fc321d2e ON |
904 | why |= SIGNAL_CLD_STOPPED; |
905 | ||
906 | if (why) { | |
021e1ae3 | 907 | /* |
ae6d2ed7 | 908 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
909 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
910 | * notify its parent. See get_signal_to_deliver(). | |
911 | */ | |
ad16a460 ON |
912 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
913 | signal->group_stop_count = 0; | |
914 | signal->group_exit_code = 0; | |
1da177e4 | 915 | } |
1da177e4 | 916 | } |
7e695a5e | 917 | |
def8cf72 | 918 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
919 | } |
920 | ||
71f11dc0 ON |
921 | /* |
922 | * Test if P wants to take SIG. After we've checked all threads with this, | |
923 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
924 | * blocking SIG were ruled out because they are not running and already | |
925 | * have pending signals. Such threads will dequeue from the shared queue | |
926 | * as soon as they're available, so putting the signal on the shared queue | |
927 | * will be equivalent to sending it to one such thread. | |
928 | */ | |
929 | static inline int wants_signal(int sig, struct task_struct *p) | |
930 | { | |
931 | if (sigismember(&p->blocked, sig)) | |
932 | return 0; | |
933 | if (p->flags & PF_EXITING) | |
934 | return 0; | |
935 | if (sig == SIGKILL) | |
936 | return 1; | |
937 | if (task_is_stopped_or_traced(p)) | |
938 | return 0; | |
939 | return task_curr(p) || !signal_pending(p); | |
940 | } | |
941 | ||
5fcd835b | 942 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
943 | { |
944 | struct signal_struct *signal = p->signal; | |
945 | struct task_struct *t; | |
946 | ||
947 | /* | |
948 | * Now find a thread we can wake up to take the signal off the queue. | |
949 | * | |
950 | * If the main thread wants the signal, it gets first crack. | |
951 | * Probably the least surprising to the average bear. | |
952 | */ | |
953 | if (wants_signal(sig, p)) | |
954 | t = p; | |
5fcd835b | 955 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
956 | /* |
957 | * There is just one thread and it does not need to be woken. | |
958 | * It will dequeue unblocked signals before it runs again. | |
959 | */ | |
960 | return; | |
961 | else { | |
962 | /* | |
963 | * Otherwise try to find a suitable thread. | |
964 | */ | |
965 | t = signal->curr_target; | |
966 | while (!wants_signal(sig, t)) { | |
967 | t = next_thread(t); | |
968 | if (t == signal->curr_target) | |
969 | /* | |
970 | * No thread needs to be woken. | |
971 | * Any eligible threads will see | |
972 | * the signal in the queue soon. | |
973 | */ | |
974 | return; | |
975 | } | |
976 | signal->curr_target = t; | |
977 | } | |
978 | ||
979 | /* | |
980 | * Found a killable thread. If the signal will be fatal, | |
981 | * then start taking the whole group down immediately. | |
982 | */ | |
fae5fa44 ON |
983 | if (sig_fatal(p, sig) && |
984 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 985 | !sigismember(&t->real_blocked, sig) && |
a288eecc | 986 | (sig == SIGKILL || !t->ptrace)) { |
71f11dc0 ON |
987 | /* |
988 | * This signal will be fatal to the whole group. | |
989 | */ | |
990 | if (!sig_kernel_coredump(sig)) { | |
991 | /* | |
992 | * Start a group exit and wake everybody up. | |
993 | * This way we don't have other threads | |
994 | * running and doing things after a slower | |
995 | * thread has the fatal signal pending. | |
996 | */ | |
997 | signal->flags = SIGNAL_GROUP_EXIT; | |
998 | signal->group_exit_code = sig; | |
999 | signal->group_stop_count = 0; | |
1000 | t = p; | |
1001 | do { | |
6dfca329 | 1002 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
1003 | sigaddset(&t->pending.signal, SIGKILL); |
1004 | signal_wake_up(t, 1); | |
1005 | } while_each_thread(p, t); | |
1006 | return; | |
1007 | } | |
1008 | } | |
1009 | ||
1010 | /* | |
1011 | * The signal is already in the shared-pending queue. | |
1012 | * Tell the chosen thread to wake up and dequeue it. | |
1013 | */ | |
1014 | signal_wake_up(t, sig == SIGKILL); | |
1015 | return; | |
1016 | } | |
1017 | ||
af7fff9c PE |
1018 | static inline int legacy_queue(struct sigpending *signals, int sig) |
1019 | { | |
1020 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
1021 | } | |
1022 | ||
6b550f94 SH |
1023 | #ifdef CONFIG_USER_NS |
1024 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1025 | { | |
1026 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
1027 | return; | |
1028 | ||
1029 | if (SI_FROMKERNEL(info)) | |
1030 | return; | |
1031 | ||
078de5f7 EB |
1032 | rcu_read_lock(); |
1033 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
1034 | make_kuid(current_user_ns(), info->si_uid)); | |
1035 | rcu_read_unlock(); | |
6b550f94 SH |
1036 | } |
1037 | #else | |
1038 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1039 | { | |
1040 | return; | |
1041 | } | |
1042 | #endif | |
1043 | ||
7978b567 SB |
1044 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1045 | int group, int from_ancestor_ns) | |
1da177e4 | 1046 | { |
2ca3515a | 1047 | struct sigpending *pending; |
6e65acba | 1048 | struct sigqueue *q; |
7a0aeb14 | 1049 | int override_rlimit; |
6c303d3a | 1050 | int ret = 0, result; |
0a16b607 | 1051 | |
6e65acba | 1052 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1053 | |
6c303d3a | 1054 | result = TRACE_SIGNAL_IGNORED; |
629d362b ON |
1055 | if (!prepare_signal(sig, t, |
1056 | from_ancestor_ns || (info == SEND_SIG_FORCED))) | |
6c303d3a | 1057 | goto ret; |
2ca3515a ON |
1058 | |
1059 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
1060 | /* |
1061 | * Short-circuit ignored signals and support queuing | |
1062 | * exactly one non-rt signal, so that we can get more | |
1063 | * detailed information about the cause of the signal. | |
1064 | */ | |
6c303d3a | 1065 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1066 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1067 | goto ret; |
1068 | ||
1069 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1070 | /* |
1071 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1072 | * or SIGKILL. | |
1073 | */ | |
b67a1b9e | 1074 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1075 | goto out_set; |
1076 | ||
5aba085e RD |
1077 | /* |
1078 | * Real-time signals must be queued if sent by sigqueue, or | |
1079 | * some other real-time mechanism. It is implementation | |
1080 | * defined whether kill() does so. We attempt to do so, on | |
1081 | * the principle of least surprise, but since kill is not | |
1082 | * allowed to fail with EAGAIN when low on memory we just | |
1083 | * make sure at least one signal gets delivered and don't | |
1084 | * pass on the info struct. | |
1085 | */ | |
7a0aeb14 VN |
1086 | if (sig < SIGRTMIN) |
1087 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1088 | else | |
1089 | override_rlimit = 0; | |
1090 | ||
f84d49b2 | 1091 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1092 | override_rlimit); |
1da177e4 | 1093 | if (q) { |
2ca3515a | 1094 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1095 | switch ((unsigned long) info) { |
b67a1b9e | 1096 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1097 | q->info.si_signo = sig; |
1098 | q->info.si_errno = 0; | |
1099 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1100 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1101 | task_active_pid_ns(t)); |
078de5f7 | 1102 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1103 | break; |
b67a1b9e | 1104 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1105 | q->info.si_signo = sig; |
1106 | q->info.si_errno = 0; | |
1107 | q->info.si_code = SI_KERNEL; | |
1108 | q->info.si_pid = 0; | |
1109 | q->info.si_uid = 0; | |
1110 | break; | |
1111 | default: | |
1112 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1113 | if (from_ancestor_ns) |
1114 | q->info.si_pid = 0; | |
1da177e4 LT |
1115 | break; |
1116 | } | |
6b550f94 SH |
1117 | |
1118 | userns_fixup_signal_uid(&q->info, t); | |
1119 | ||
621d3121 | 1120 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1121 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1122 | /* | |
1123 | * Queue overflow, abort. We may abort if the | |
1124 | * signal was rt and sent by user using something | |
1125 | * other than kill(). | |
1126 | */ | |
6c303d3a ON |
1127 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1128 | ret = -EAGAIN; | |
1129 | goto ret; | |
ba005e1f MH |
1130 | } else { |
1131 | /* | |
1132 | * This is a silent loss of information. We still | |
1133 | * send the signal, but the *info bits are lost. | |
1134 | */ | |
6c303d3a | 1135 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1136 | } |
1da177e4 LT |
1137 | } |
1138 | ||
1139 | out_set: | |
53c30337 | 1140 | signalfd_notify(t, sig); |
2ca3515a | 1141 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1142 | complete_signal(sig, t, group); |
6c303d3a ON |
1143 | ret: |
1144 | trace_signal_generate(sig, info, t, group, result); | |
1145 | return ret; | |
1da177e4 LT |
1146 | } |
1147 | ||
7978b567 SB |
1148 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1149 | int group) | |
1150 | { | |
921cf9f6 SB |
1151 | int from_ancestor_ns = 0; |
1152 | ||
1153 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1154 | from_ancestor_ns = si_fromuser(info) && |
1155 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1156 | #endif |
1157 | ||
1158 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1159 | } |
1160 | ||
4aaefee5 | 1161 | static void print_fatal_signal(int signr) |
45807a1d | 1162 | { |
4aaefee5 | 1163 | struct pt_regs *regs = signal_pt_regs(); |
5d1fadc1 | 1164 | printk(KERN_INFO "%s/%d: potentially unexpected fatal signal %d.\n", |
ba25f9dc | 1165 | current->comm, task_pid_nr(current), signr); |
45807a1d | 1166 | |
ca5cd877 | 1167 | #if defined(__i386__) && !defined(__arch_um__) |
5d1fadc1 | 1168 | printk(KERN_INFO "code at %08lx: ", regs->ip); |
45807a1d IM |
1169 | { |
1170 | int i; | |
1171 | for (i = 0; i < 16; i++) { | |
1172 | unsigned char insn; | |
1173 | ||
b45c6e76 AK |
1174 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1175 | break; | |
5d1fadc1 | 1176 | printk(KERN_CONT "%02x ", insn); |
45807a1d IM |
1177 | } |
1178 | } | |
5d1fadc1 | 1179 | printk(KERN_CONT "\n"); |
45807a1d | 1180 | #endif |
3a9f84d3 | 1181 | preempt_disable(); |
45807a1d | 1182 | show_regs(regs); |
3a9f84d3 | 1183 | preempt_enable(); |
45807a1d IM |
1184 | } |
1185 | ||
1186 | static int __init setup_print_fatal_signals(char *str) | |
1187 | { | |
1188 | get_option (&str, &print_fatal_signals); | |
1189 | ||
1190 | return 1; | |
1191 | } | |
1192 | ||
1193 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1194 | |
4cd4b6d4 PE |
1195 | int |
1196 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1197 | { | |
1198 | return send_signal(sig, info, p, 1); | |
1199 | } | |
1200 | ||
1da177e4 LT |
1201 | static int |
1202 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1203 | { | |
4cd4b6d4 | 1204 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1205 | } |
1206 | ||
4a30debf ON |
1207 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1208 | bool group) | |
1209 | { | |
1210 | unsigned long flags; | |
1211 | int ret = -ESRCH; | |
1212 | ||
1213 | if (lock_task_sighand(p, &flags)) { | |
1214 | ret = send_signal(sig, info, p, group); | |
1215 | unlock_task_sighand(p, &flags); | |
1216 | } | |
1217 | ||
1218 | return ret; | |
1219 | } | |
1220 | ||
1da177e4 LT |
1221 | /* |
1222 | * Force a signal that the process can't ignore: if necessary | |
1223 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1224 | * |
1225 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1226 | * since we do not want to have a signal handler that was blocked | |
1227 | * be invoked when user space had explicitly blocked it. | |
1228 | * | |
80fe728d ON |
1229 | * We don't want to have recursive SIGSEGV's etc, for example, |
1230 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1231 | */ |
1da177e4 LT |
1232 | int |
1233 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1234 | { | |
1235 | unsigned long int flags; | |
ae74c3b6 LT |
1236 | int ret, blocked, ignored; |
1237 | struct k_sigaction *action; | |
1da177e4 LT |
1238 | |
1239 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1240 | action = &t->sighand->action[sig-1]; |
1241 | ignored = action->sa.sa_handler == SIG_IGN; | |
1242 | blocked = sigismember(&t->blocked, sig); | |
1243 | if (blocked || ignored) { | |
1244 | action->sa.sa_handler = SIG_DFL; | |
1245 | if (blocked) { | |
1246 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1247 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1248 | } |
1da177e4 | 1249 | } |
80fe728d ON |
1250 | if (action->sa.sa_handler == SIG_DFL) |
1251 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1252 | ret = specific_send_sig_info(sig, info, t); |
1253 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1254 | ||
1255 | return ret; | |
1256 | } | |
1257 | ||
1da177e4 LT |
1258 | /* |
1259 | * Nuke all other threads in the group. | |
1260 | */ | |
09faef11 | 1261 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1262 | { |
09faef11 ON |
1263 | struct task_struct *t = p; |
1264 | int count = 0; | |
1da177e4 | 1265 | |
1da177e4 LT |
1266 | p->signal->group_stop_count = 0; |
1267 | ||
09faef11 | 1268 | while_each_thread(p, t) { |
6dfca329 | 1269 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1270 | count++; |
1271 | ||
1272 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1273 | if (t->exit_state) |
1274 | continue; | |
1da177e4 | 1275 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1276 | signal_wake_up(t, 1); |
1277 | } | |
09faef11 ON |
1278 | |
1279 | return count; | |
1da177e4 LT |
1280 | } |
1281 | ||
b8ed374e NK |
1282 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1283 | unsigned long *flags) | |
f63ee72e ON |
1284 | { |
1285 | struct sighand_struct *sighand; | |
1286 | ||
1287 | for (;;) { | |
a841796f PM |
1288 | local_irq_save(*flags); |
1289 | rcu_read_lock(); | |
f63ee72e | 1290 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1291 | if (unlikely(sighand == NULL)) { |
1292 | rcu_read_unlock(); | |
1293 | local_irq_restore(*flags); | |
f63ee72e | 1294 | break; |
a841796f | 1295 | } |
f63ee72e | 1296 | |
a841796f PM |
1297 | spin_lock(&sighand->siglock); |
1298 | if (likely(sighand == tsk->sighand)) { | |
1299 | rcu_read_unlock(); | |
f63ee72e | 1300 | break; |
a841796f PM |
1301 | } |
1302 | spin_unlock(&sighand->siglock); | |
1303 | rcu_read_unlock(); | |
1304 | local_irq_restore(*flags); | |
f63ee72e ON |
1305 | } |
1306 | ||
1307 | return sighand; | |
1308 | } | |
1309 | ||
c69e8d9c DH |
1310 | /* |
1311 | * send signal info to all the members of a group | |
c69e8d9c | 1312 | */ |
1da177e4 LT |
1313 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1314 | { | |
694f690d DH |
1315 | int ret; |
1316 | ||
1317 | rcu_read_lock(); | |
1318 | ret = check_kill_permission(sig, info, p); | |
1319 | rcu_read_unlock(); | |
f63ee72e | 1320 | |
4a30debf ON |
1321 | if (!ret && sig) |
1322 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1323 | |
1324 | return ret; | |
1325 | } | |
1326 | ||
1327 | /* | |
146a505d | 1328 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1329 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1330 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1331 | */ |
c4b92fc1 | 1332 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1333 | { |
1334 | struct task_struct *p = NULL; | |
1335 | int retval, success; | |
1336 | ||
1da177e4 LT |
1337 | success = 0; |
1338 | retval = -ESRCH; | |
c4b92fc1 | 1339 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1340 | int err = group_send_sig_info(sig, info, p); |
1341 | success |= !err; | |
1342 | retval = err; | |
c4b92fc1 | 1343 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1344 | return success ? 0 : retval; |
1345 | } | |
1346 | ||
c4b92fc1 | 1347 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1348 | { |
d36174bc | 1349 | int error = -ESRCH; |
1da177e4 LT |
1350 | struct task_struct *p; |
1351 | ||
e56d0903 | 1352 | rcu_read_lock(); |
d36174bc | 1353 | retry: |
c4b92fc1 | 1354 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1355 | if (p) { |
1da177e4 | 1356 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1357 | if (unlikely(error == -ESRCH)) |
1358 | /* | |
1359 | * The task was unhashed in between, try again. | |
1360 | * If it is dead, pid_task() will return NULL, | |
1361 | * if we race with de_thread() it will find the | |
1362 | * new leader. | |
1363 | */ | |
1364 | goto retry; | |
1365 | } | |
e56d0903 | 1366 | rcu_read_unlock(); |
6ca25b55 | 1367 | |
1da177e4 LT |
1368 | return error; |
1369 | } | |
1370 | ||
5aba085e | 1371 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1372 | { |
1373 | int error; | |
1374 | rcu_read_lock(); | |
b488893a | 1375 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1376 | rcu_read_unlock(); |
1377 | return error; | |
1378 | } | |
1379 | ||
d178bc3a SH |
1380 | static int kill_as_cred_perm(const struct cred *cred, |
1381 | struct task_struct *target) | |
1382 | { | |
1383 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1384 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1385 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1386 | return 0; |
1387 | return 1; | |
1388 | } | |
1389 | ||
2425c08b | 1390 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1391 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1392 | const struct cred *cred, u32 secid) | |
46113830 HW |
1393 | { |
1394 | int ret = -EINVAL; | |
1395 | struct task_struct *p; | |
14d8c9f3 | 1396 | unsigned long flags; |
46113830 HW |
1397 | |
1398 | if (!valid_signal(sig)) | |
1399 | return ret; | |
1400 | ||
14d8c9f3 | 1401 | rcu_read_lock(); |
2425c08b | 1402 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1403 | if (!p) { |
1404 | ret = -ESRCH; | |
1405 | goto out_unlock; | |
1406 | } | |
d178bc3a | 1407 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1408 | ret = -EPERM; |
1409 | goto out_unlock; | |
1410 | } | |
8f95dc58 DQ |
1411 | ret = security_task_kill(p, info, sig, secid); |
1412 | if (ret) | |
1413 | goto out_unlock; | |
14d8c9f3 TG |
1414 | |
1415 | if (sig) { | |
1416 | if (lock_task_sighand(p, &flags)) { | |
1417 | ret = __send_signal(sig, info, p, 1, 0); | |
1418 | unlock_task_sighand(p, &flags); | |
1419 | } else | |
1420 | ret = -ESRCH; | |
46113830 HW |
1421 | } |
1422 | out_unlock: | |
14d8c9f3 | 1423 | rcu_read_unlock(); |
46113830 HW |
1424 | return ret; |
1425 | } | |
d178bc3a | 1426 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1427 | |
1428 | /* | |
1429 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1430 | * | |
1431 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1432 | * is probably wrong. Should make it like BSD or SYSV. | |
1433 | */ | |
1434 | ||
bc64efd2 | 1435 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1436 | { |
8d42db18 | 1437 | int ret; |
d5df763b PE |
1438 | |
1439 | if (pid > 0) { | |
1440 | rcu_read_lock(); | |
1441 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1442 | rcu_read_unlock(); | |
1443 | return ret; | |
1444 | } | |
1445 | ||
1446 | read_lock(&tasklist_lock); | |
1447 | if (pid != -1) { | |
1448 | ret = __kill_pgrp_info(sig, info, | |
1449 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1450 | } else { | |
1da177e4 LT |
1451 | int retval = 0, count = 0; |
1452 | struct task_struct * p; | |
1453 | ||
1da177e4 | 1454 | for_each_process(p) { |
d25141a8 SB |
1455 | if (task_pid_vnr(p) > 1 && |
1456 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1457 | int err = group_send_sig_info(sig, info, p); |
1458 | ++count; | |
1459 | if (err != -EPERM) | |
1460 | retval = err; | |
1461 | } | |
1462 | } | |
8d42db18 | 1463 | ret = count ? retval : -ESRCH; |
1da177e4 | 1464 | } |
d5df763b PE |
1465 | read_unlock(&tasklist_lock); |
1466 | ||
8d42db18 | 1467 | return ret; |
1da177e4 LT |
1468 | } |
1469 | ||
1470 | /* | |
1471 | * These are for backward compatibility with the rest of the kernel source. | |
1472 | */ | |
1473 | ||
5aba085e | 1474 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1475 | { |
1da177e4 LT |
1476 | /* |
1477 | * Make sure legacy kernel users don't send in bad values | |
1478 | * (normal paths check this in check_kill_permission). | |
1479 | */ | |
7ed20e1a | 1480 | if (!valid_signal(sig)) |
1da177e4 LT |
1481 | return -EINVAL; |
1482 | ||
4a30debf | 1483 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1484 | } |
1485 | ||
b67a1b9e ON |
1486 | #define __si_special(priv) \ |
1487 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1488 | ||
1da177e4 LT |
1489 | int |
1490 | send_sig(int sig, struct task_struct *p, int priv) | |
1491 | { | |
b67a1b9e | 1492 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1493 | } |
1494 | ||
1da177e4 LT |
1495 | void |
1496 | force_sig(int sig, struct task_struct *p) | |
1497 | { | |
b67a1b9e | 1498 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1499 | } |
1500 | ||
1501 | /* | |
1502 | * When things go south during signal handling, we | |
1503 | * will force a SIGSEGV. And if the signal that caused | |
1504 | * the problem was already a SIGSEGV, we'll want to | |
1505 | * make sure we don't even try to deliver the signal.. | |
1506 | */ | |
1507 | int | |
1508 | force_sigsegv(int sig, struct task_struct *p) | |
1509 | { | |
1510 | if (sig == SIGSEGV) { | |
1511 | unsigned long flags; | |
1512 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1513 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1514 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1515 | } | |
1516 | force_sig(SIGSEGV, p); | |
1517 | return 0; | |
1518 | } | |
1519 | ||
c4b92fc1 EB |
1520 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1521 | { | |
146a505d PE |
1522 | int ret; |
1523 | ||
1524 | read_lock(&tasklist_lock); | |
1525 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1526 | read_unlock(&tasklist_lock); | |
1527 | ||
1528 | return ret; | |
c4b92fc1 EB |
1529 | } |
1530 | EXPORT_SYMBOL(kill_pgrp); | |
1531 | ||
1532 | int kill_pid(struct pid *pid, int sig, int priv) | |
1533 | { | |
1534 | return kill_pid_info(sig, __si_special(priv), pid); | |
1535 | } | |
1536 | EXPORT_SYMBOL(kill_pid); | |
1537 | ||
1da177e4 LT |
1538 | /* |
1539 | * These functions support sending signals using preallocated sigqueue | |
1540 | * structures. This is needed "because realtime applications cannot | |
1541 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1542 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1543 | * we allocate the sigqueue structure from the timer_create. If this |
1544 | * allocation fails we are able to report the failure to the application | |
1545 | * with an EAGAIN error. | |
1546 | */ | |
1da177e4 LT |
1547 | struct sigqueue *sigqueue_alloc(void) |
1548 | { | |
f84d49b2 | 1549 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1550 | |
f84d49b2 | 1551 | if (q) |
1da177e4 | 1552 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1553 | |
1554 | return q; | |
1da177e4 LT |
1555 | } |
1556 | ||
1557 | void sigqueue_free(struct sigqueue *q) | |
1558 | { | |
1559 | unsigned long flags; | |
60187d27 ON |
1560 | spinlock_t *lock = ¤t->sighand->siglock; |
1561 | ||
1da177e4 LT |
1562 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1563 | /* | |
c8e85b4f ON |
1564 | * We must hold ->siglock while testing q->list |
1565 | * to serialize with collect_signal() or with | |
da7978b0 | 1566 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1567 | */ |
60187d27 | 1568 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1569 | q->flags &= ~SIGQUEUE_PREALLOC; |
1570 | /* | |
1571 | * If it is queued it will be freed when dequeued, | |
1572 | * like the "regular" sigqueue. | |
1573 | */ | |
60187d27 | 1574 | if (!list_empty(&q->list)) |
c8e85b4f | 1575 | q = NULL; |
60187d27 ON |
1576 | spin_unlock_irqrestore(lock, flags); |
1577 | ||
c8e85b4f ON |
1578 | if (q) |
1579 | __sigqueue_free(q); | |
1da177e4 LT |
1580 | } |
1581 | ||
ac5c2153 | 1582 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1583 | { |
e62e6650 | 1584 | int sig = q->info.si_signo; |
2ca3515a | 1585 | struct sigpending *pending; |
e62e6650 | 1586 | unsigned long flags; |
163566f6 | 1587 | int ret, result; |
2ca3515a | 1588 | |
4cd4b6d4 | 1589 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1590 | |
1591 | ret = -1; | |
1592 | if (!likely(lock_task_sighand(t, &flags))) | |
1593 | goto ret; | |
1594 | ||
7e695a5e | 1595 | ret = 1; /* the signal is ignored */ |
163566f6 | 1596 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1597 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1598 | goto out; |
1599 | ||
1600 | ret = 0; | |
9e3bd6c3 PE |
1601 | if (unlikely(!list_empty(&q->list))) { |
1602 | /* | |
1603 | * If an SI_TIMER entry is already queue just increment | |
1604 | * the overrun count. | |
1605 | */ | |
9e3bd6c3 PE |
1606 | BUG_ON(q->info.si_code != SI_TIMER); |
1607 | q->info.si_overrun++; | |
163566f6 | 1608 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1609 | goto out; |
9e3bd6c3 | 1610 | } |
ba661292 | 1611 | q->info.si_overrun = 0; |
9e3bd6c3 | 1612 | |
9e3bd6c3 | 1613 | signalfd_notify(t, sig); |
2ca3515a | 1614 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1615 | list_add_tail(&q->list, &pending->list); |
1616 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1617 | complete_signal(sig, t, group); |
163566f6 | 1618 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1619 | out: |
163566f6 | 1620 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1621 | unlock_task_sighand(t, &flags); |
1622 | ret: | |
1623 | return ret; | |
9e3bd6c3 PE |
1624 | } |
1625 | ||
1da177e4 LT |
1626 | /* |
1627 | * Let a parent know about the death of a child. | |
1628 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1629 | * |
53c8f9f1 ON |
1630 | * Returns true if our parent ignored us and so we've switched to |
1631 | * self-reaping. | |
1da177e4 | 1632 | */ |
53c8f9f1 | 1633 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1634 | { |
1635 | struct siginfo info; | |
1636 | unsigned long flags; | |
1637 | struct sighand_struct *psig; | |
53c8f9f1 | 1638 | bool autoreap = false; |
6fac4829 | 1639 | cputime_t utime, stime; |
1da177e4 LT |
1640 | |
1641 | BUG_ON(sig == -1); | |
1642 | ||
1643 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1644 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1645 | |
d21142ec | 1646 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1647 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1648 | ||
b6e238dc ON |
1649 | if (sig != SIGCHLD) { |
1650 | /* | |
1651 | * This is only possible if parent == real_parent. | |
1652 | * Check if it has changed security domain. | |
1653 | */ | |
1654 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1655 | sig = SIGCHLD; | |
1656 | } | |
1657 | ||
1da177e4 LT |
1658 | info.si_signo = sig; |
1659 | info.si_errno = 0; | |
b488893a | 1660 | /* |
32084504 EB |
1661 | * We are under tasklist_lock here so our parent is tied to |
1662 | * us and cannot change. | |
b488893a | 1663 | * |
32084504 EB |
1664 | * task_active_pid_ns will always return the same pid namespace |
1665 | * until a task passes through release_task. | |
b488893a PE |
1666 | * |
1667 | * write_lock() currently calls preempt_disable() which is the | |
1668 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1669 | * correct to rely on this | |
1670 | */ | |
1671 | rcu_read_lock(); | |
32084504 | 1672 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1673 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1674 | task_uid(tsk)); | |
b488893a PE |
1675 | rcu_read_unlock(); |
1676 | ||
6fac4829 FW |
1677 | task_cputime(tsk, &utime, &stime); |
1678 | info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime); | |
1679 | info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1680 | |
1681 | info.si_status = tsk->exit_code & 0x7f; | |
1682 | if (tsk->exit_code & 0x80) | |
1683 | info.si_code = CLD_DUMPED; | |
1684 | else if (tsk->exit_code & 0x7f) | |
1685 | info.si_code = CLD_KILLED; | |
1686 | else { | |
1687 | info.si_code = CLD_EXITED; | |
1688 | info.si_status = tsk->exit_code >> 8; | |
1689 | } | |
1690 | ||
1691 | psig = tsk->parent->sighand; | |
1692 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1693 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1694 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1695 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1696 | /* | |
1697 | * We are exiting and our parent doesn't care. POSIX.1 | |
1698 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1699 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1700 | * automatically and not left for our parent's wait4 call. | |
1701 | * Rather than having the parent do it as a magic kind of | |
1702 | * signal handler, we just set this to tell do_exit that we | |
1703 | * can be cleaned up without becoming a zombie. Note that | |
1704 | * we still call __wake_up_parent in this case, because a | |
1705 | * blocked sys_wait4 might now return -ECHILD. | |
1706 | * | |
1707 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1708 | * is implementation-defined: we do (if you don't want | |
1709 | * it, just use SIG_IGN instead). | |
1710 | */ | |
53c8f9f1 | 1711 | autoreap = true; |
1da177e4 | 1712 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1713 | sig = 0; |
1da177e4 | 1714 | } |
53c8f9f1 | 1715 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1716 | __group_send_sig_info(sig, &info, tsk->parent); |
1717 | __wake_up_parent(tsk, tsk->parent); | |
1718 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1719 | |
53c8f9f1 | 1720 | return autoreap; |
1da177e4 LT |
1721 | } |
1722 | ||
75b95953 TH |
1723 | /** |
1724 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1725 | * @tsk: task reporting the state change | |
1726 | * @for_ptracer: the notification is for ptracer | |
1727 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1728 | * | |
1729 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1730 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1731 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1732 | * | |
1733 | * CONTEXT: | |
1734 | * Must be called with tasklist_lock at least read locked. | |
1735 | */ | |
1736 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1737 | bool for_ptracer, int why) | |
1da177e4 LT |
1738 | { |
1739 | struct siginfo info; | |
1740 | unsigned long flags; | |
bc505a47 | 1741 | struct task_struct *parent; |
1da177e4 | 1742 | struct sighand_struct *sighand; |
6fac4829 | 1743 | cputime_t utime, stime; |
1da177e4 | 1744 | |
75b95953 | 1745 | if (for_ptracer) { |
bc505a47 | 1746 | parent = tsk->parent; |
75b95953 | 1747 | } else { |
bc505a47 ON |
1748 | tsk = tsk->group_leader; |
1749 | parent = tsk->real_parent; | |
1750 | } | |
1751 | ||
1da177e4 LT |
1752 | info.si_signo = SIGCHLD; |
1753 | info.si_errno = 0; | |
b488893a | 1754 | /* |
5aba085e | 1755 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1756 | */ |
1757 | rcu_read_lock(); | |
17cf22c3 | 1758 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1759 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1760 | rcu_read_unlock(); |
1761 | ||
6fac4829 FW |
1762 | task_cputime(tsk, &utime, &stime); |
1763 | info.si_utime = cputime_to_clock_t(utime); | |
1764 | info.si_stime = cputime_to_clock_t(stime); | |
1da177e4 LT |
1765 | |
1766 | info.si_code = why; | |
1767 | switch (why) { | |
1768 | case CLD_CONTINUED: | |
1769 | info.si_status = SIGCONT; | |
1770 | break; | |
1771 | case CLD_STOPPED: | |
1772 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1773 | break; | |
1774 | case CLD_TRAPPED: | |
1775 | info.si_status = tsk->exit_code & 0x7f; | |
1776 | break; | |
1777 | default: | |
1778 | BUG(); | |
1779 | } | |
1780 | ||
1781 | sighand = parent->sighand; | |
1782 | spin_lock_irqsave(&sighand->siglock, flags); | |
1783 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1784 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1785 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1786 | /* | |
1787 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1788 | */ | |
1789 | __wake_up_parent(tsk, parent); | |
1790 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1791 | } | |
1792 | ||
d5f70c00 ON |
1793 | static inline int may_ptrace_stop(void) |
1794 | { | |
d21142ec | 1795 | if (!likely(current->ptrace)) |
d5f70c00 | 1796 | return 0; |
d5f70c00 ON |
1797 | /* |
1798 | * Are we in the middle of do_coredump? | |
1799 | * If so and our tracer is also part of the coredump stopping | |
1800 | * is a deadlock situation, and pointless because our tracer | |
1801 | * is dead so don't allow us to stop. | |
1802 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1803 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1804 | * is safe to enter schedule(). |
9899d11f ON |
1805 | * |
1806 | * This is almost outdated, a task with the pending SIGKILL can't | |
1807 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1808 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1809 | */ |
999d9fc1 | 1810 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1811 | unlikely(current->mm == current->parent->mm)) |
1812 | return 0; | |
1813 | ||
1814 | return 1; | |
1815 | } | |
1816 | ||
1a669c2f | 1817 | /* |
5aba085e | 1818 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1819 | * Called with the siglock held. |
1820 | */ | |
1821 | static int sigkill_pending(struct task_struct *tsk) | |
1822 | { | |
3d749b9e ON |
1823 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1824 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1825 | } |
1826 | ||
1da177e4 LT |
1827 | /* |
1828 | * This must be called with current->sighand->siglock held. | |
1829 | * | |
1830 | * This should be the path for all ptrace stops. | |
1831 | * We always set current->last_siginfo while stopped here. | |
1832 | * That makes it a way to test a stopped process for | |
1833 | * being ptrace-stopped vs being job-control-stopped. | |
1834 | * | |
20686a30 ON |
1835 | * If we actually decide not to stop at all because the tracer |
1836 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1837 | */ |
fe1bc6a0 | 1838 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1839 | __releases(¤t->sighand->siglock) |
1840 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1841 | { |
ceb6bd67 TH |
1842 | bool gstop_done = false; |
1843 | ||
1a669c2f RM |
1844 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1845 | /* | |
1846 | * The arch code has something special to do before a | |
1847 | * ptrace stop. This is allowed to block, e.g. for faults | |
1848 | * on user stack pages. We can't keep the siglock while | |
1849 | * calling arch_ptrace_stop, so we must release it now. | |
1850 | * To preserve proper semantics, we must do this before | |
1851 | * any signal bookkeeping like checking group_stop_count. | |
1852 | * Meanwhile, a SIGKILL could come in before we retake the | |
1853 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1854 | * So after regaining the lock, we must check for SIGKILL. | |
1855 | */ | |
1856 | spin_unlock_irq(¤t->sighand->siglock); | |
1857 | arch_ptrace_stop(exit_code, info); | |
1858 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1859 | if (sigkill_pending(current)) |
1860 | return; | |
1a669c2f RM |
1861 | } |
1862 | ||
1da177e4 | 1863 | /* |
81be24b8 TH |
1864 | * We're committing to trapping. TRACED should be visible before |
1865 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1866 | * Also, transition to TRACED and updates to ->jobctl should be | |
1867 | * atomic with respect to siglock and should be done after the arch | |
1868 | * hook as siglock is released and regrabbed across it. | |
1da177e4 | 1869 | */ |
81be24b8 | 1870 | set_current_state(TASK_TRACED); |
1da177e4 LT |
1871 | |
1872 | current->last_siginfo = info; | |
1873 | current->exit_code = exit_code; | |
1874 | ||
d79fdd6d | 1875 | /* |
0ae8ce1c TH |
1876 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1877 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1878 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1879 | * could be clear now. We act as if SIGCONT is received after | |
1880 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1881 | */ |
a8f072c1 | 1882 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1883 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1884 | |
fb1d910c | 1885 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1886 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1887 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1888 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1889 | |
81be24b8 | 1890 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1891 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1892 | |
1da177e4 LT |
1893 | spin_unlock_irq(¤t->sighand->siglock); |
1894 | read_lock(&tasklist_lock); | |
3d749b9e | 1895 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1896 | /* |
1897 | * Notify parents of the stop. | |
1898 | * | |
1899 | * While ptraced, there are two parents - the ptracer and | |
1900 | * the real_parent of the group_leader. The ptracer should | |
1901 | * know about every stop while the real parent is only | |
1902 | * interested in the completion of group stop. The states | |
1903 | * for the two don't interact with each other. Notify | |
1904 | * separately unless they're gonna be duplicates. | |
1905 | */ | |
1906 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1907 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1908 | do_notify_parent_cldstop(current, false, why); |
1909 | ||
53da1d94 MS |
1910 | /* |
1911 | * Don't want to allow preemption here, because | |
1912 | * sys_ptrace() needs this task to be inactive. | |
1913 | * | |
1914 | * XXX: implement read_unlock_no_resched(). | |
1915 | */ | |
1916 | preempt_disable(); | |
1da177e4 | 1917 | read_unlock(&tasklist_lock); |
53da1d94 | 1918 | preempt_enable_no_resched(); |
5d8f72b5 | 1919 | freezable_schedule(); |
1da177e4 LT |
1920 | } else { |
1921 | /* | |
1922 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1923 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1924 | * |
1925 | * If @gstop_done, the ptracer went away between group stop | |
1926 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1927 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1928 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1929 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1930 | */ |
ceb6bd67 TH |
1931 | if (gstop_done) |
1932 | do_notify_parent_cldstop(current, false, why); | |
1933 | ||
9899d11f | 1934 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 1935 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1936 | if (clear_code) |
1937 | current->exit_code = 0; | |
6405f7f4 | 1938 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1939 | } |
1940 | ||
1941 | /* | |
1942 | * We are back. Now reacquire the siglock before touching | |
1943 | * last_siginfo, so that we are sure to have synchronized with | |
1944 | * any signal-sending on another CPU that wants to examine it. | |
1945 | */ | |
1946 | spin_lock_irq(¤t->sighand->siglock); | |
1947 | current->last_siginfo = NULL; | |
1948 | ||
544b2c91 TH |
1949 | /* LISTENING can be set only during STOP traps, clear it */ |
1950 | current->jobctl &= ~JOBCTL_LISTENING; | |
1951 | ||
1da177e4 LT |
1952 | /* |
1953 | * Queued signals ignored us while we were stopped for tracing. | |
1954 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1955 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1956 | */ |
b74d0deb | 1957 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1958 | } |
1959 | ||
3544d72a | 1960 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1961 | { |
1962 | siginfo_t info; | |
1963 | ||
1da177e4 | 1964 | memset(&info, 0, sizeof info); |
3544d72a | 1965 | info.si_signo = signr; |
1da177e4 | 1966 | info.si_code = exit_code; |
b488893a | 1967 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1968 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1969 | |
1970 | /* Let the debugger run. */ | |
3544d72a TH |
1971 | ptrace_stop(exit_code, why, 1, &info); |
1972 | } | |
1973 | ||
1974 | void ptrace_notify(int exit_code) | |
1975 | { | |
1976 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
1977 | if (unlikely(current->task_works)) |
1978 | task_work_run(); | |
3544d72a | 1979 | |
1da177e4 | 1980 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1981 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1982 | spin_unlock_irq(¤t->sighand->siglock); |
1983 | } | |
1984 | ||
73ddff2b TH |
1985 | /** |
1986 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1987 | * @signr: signr causing group stop if initiating | |
1988 | * | |
1989 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1990 | * and participate in it. If already set, participate in the existing | |
1991 | * group stop. If participated in a group stop (and thus slept), %true is | |
1992 | * returned with siglock released. | |
1993 | * | |
1994 | * If ptraced, this function doesn't handle stop itself. Instead, | |
1995 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
1996 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
1997 | * places afterwards. | |
1998 | * | |
1999 | * CONTEXT: | |
2000 | * Must be called with @current->sighand->siglock held, which is released | |
2001 | * on %true return. | |
2002 | * | |
2003 | * RETURNS: | |
2004 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
2005 | * %true if participated in group stop. | |
1da177e4 | 2006 | */ |
73ddff2b TH |
2007 | static bool do_signal_stop(int signr) |
2008 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
2009 | { |
2010 | struct signal_struct *sig = current->signal; | |
1da177e4 | 2011 | |
a8f072c1 TH |
2012 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
2013 | unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; | |
f558b7e4 ON |
2014 | struct task_struct *t; |
2015 | ||
a8f072c1 TH |
2016 | /* signr will be recorded in task->jobctl for retries */ |
2017 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 2018 | |
a8f072c1 | 2019 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 2020 | unlikely(signal_group_exit(sig))) |
73ddff2b | 2021 | return false; |
1da177e4 | 2022 | /* |
408a37de TH |
2023 | * There is no group stop already in progress. We must |
2024 | * initiate one now. | |
2025 | * | |
2026 | * While ptraced, a task may be resumed while group stop is | |
2027 | * still in effect and then receive a stop signal and | |
2028 | * initiate another group stop. This deviates from the | |
2029 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2030 | * cause two group stops when !ptraced. That is why we |
2031 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2032 | * |
2033 | * The condition can be distinguished by testing whether | |
2034 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2035 | * group_exit_code in such case. | |
2036 | * | |
2037 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2038 | * an intervening stop signal is required to cause two | |
2039 | * continued events regardless of ptrace. | |
1da177e4 | 2040 | */ |
408a37de TH |
2041 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2042 | sig->group_exit_code = signr; | |
1da177e4 | 2043 | |
7dd3db54 TH |
2044 | sig->group_stop_count = 0; |
2045 | ||
2046 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2047 | sig->group_stop_count++; | |
1da177e4 | 2048 | |
d79fdd6d TH |
2049 | for (t = next_thread(current); t != current; |
2050 | t = next_thread(t)) { | |
1da177e4 | 2051 | /* |
a122b341 ON |
2052 | * Setting state to TASK_STOPPED for a group |
2053 | * stop is always done with the siglock held, | |
2054 | * so this check has no races. | |
1da177e4 | 2055 | */ |
7dd3db54 TH |
2056 | if (!task_is_stopped(t) && |
2057 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2058 | sig->group_stop_count++; |
fb1d910c TH |
2059 | if (likely(!(t->ptrace & PT_SEIZED))) |
2060 | signal_wake_up(t, 0); | |
2061 | else | |
2062 | ptrace_trap_notify(t); | |
a122b341 | 2063 | } |
d79fdd6d | 2064 | } |
1da177e4 | 2065 | } |
73ddff2b | 2066 | |
d21142ec | 2067 | if (likely(!current->ptrace)) { |
5224fa36 | 2068 | int notify = 0; |
1da177e4 | 2069 | |
5224fa36 TH |
2070 | /* |
2071 | * If there are no other threads in the group, or if there | |
2072 | * is a group stop in progress and we are the last to stop, | |
2073 | * report to the parent. | |
2074 | */ | |
2075 | if (task_participate_group_stop(current)) | |
2076 | notify = CLD_STOPPED; | |
2077 | ||
ae6d2ed7 | 2078 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
2079 | spin_unlock_irq(¤t->sighand->siglock); |
2080 | ||
62bcf9d9 TH |
2081 | /* |
2082 | * Notify the parent of the group stop completion. Because | |
2083 | * we're not holding either the siglock or tasklist_lock | |
2084 | * here, ptracer may attach inbetween; however, this is for | |
2085 | * group stop and should always be delivered to the real | |
2086 | * parent of the group leader. The new ptracer will get | |
2087 | * its notification when this task transitions into | |
2088 | * TASK_TRACED. | |
2089 | */ | |
5224fa36 TH |
2090 | if (notify) { |
2091 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2092 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2093 | read_unlock(&tasklist_lock); |
2094 | } | |
2095 | ||
2096 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
5d8f72b5 | 2097 | freezable_schedule(); |
73ddff2b | 2098 | return true; |
d79fdd6d | 2099 | } else { |
73ddff2b TH |
2100 | /* |
2101 | * While ptraced, group stop is handled by STOP trap. | |
2102 | * Schedule it and let the caller deal with it. | |
2103 | */ | |
2104 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2105 | return false; | |
ae6d2ed7 | 2106 | } |
73ddff2b | 2107 | } |
1da177e4 | 2108 | |
73ddff2b TH |
2109 | /** |
2110 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2111 | * | |
3544d72a TH |
2112 | * When PT_SEIZED, it's used for both group stop and explicit |
2113 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2114 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2115 | * the stop signal; otherwise, %SIGTRAP. | |
2116 | * | |
2117 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2118 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2119 | * |
2120 | * CONTEXT: | |
2121 | * Must be called with @current->sighand->siglock held, which may be | |
2122 | * released and re-acquired before returning with intervening sleep. | |
2123 | */ | |
2124 | static void do_jobctl_trap(void) | |
2125 | { | |
3544d72a | 2126 | struct signal_struct *signal = current->signal; |
73ddff2b | 2127 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2128 | |
3544d72a TH |
2129 | if (current->ptrace & PT_SEIZED) { |
2130 | if (!signal->group_stop_count && | |
2131 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2132 | signr = SIGTRAP; | |
2133 | WARN_ON_ONCE(!signr); | |
2134 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2135 | CLD_STOPPED); | |
2136 | } else { | |
2137 | WARN_ON_ONCE(!signr); | |
2138 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2139 | current->exit_code = 0; | |
ae6d2ed7 | 2140 | } |
1da177e4 LT |
2141 | } |
2142 | ||
94eb22d5 | 2143 | static int ptrace_signal(int signr, siginfo_t *info) |
18c98b65 | 2144 | { |
b7f9591c | 2145 | ptrace_signal_deliver(); |
8a352418 ON |
2146 | /* |
2147 | * We do not check sig_kernel_stop(signr) but set this marker | |
2148 | * unconditionally because we do not know whether debugger will | |
2149 | * change signr. This flag has no meaning unless we are going | |
2150 | * to stop after return from ptrace_stop(). In this case it will | |
2151 | * be checked in do_signal_stop(), we should only stop if it was | |
2152 | * not cleared by SIGCONT while we were sleeping. See also the | |
2153 | * comment in dequeue_signal(). | |
2154 | */ | |
2155 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2156 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2157 | |
2158 | /* We're back. Did the debugger cancel the sig? */ | |
2159 | signr = current->exit_code; | |
2160 | if (signr == 0) | |
2161 | return signr; | |
2162 | ||
2163 | current->exit_code = 0; | |
2164 | ||
5aba085e RD |
2165 | /* |
2166 | * Update the siginfo structure if the signal has | |
2167 | * changed. If the debugger wanted something | |
2168 | * specific in the siginfo structure then it should | |
2169 | * have updated *info via PTRACE_SETSIGINFO. | |
2170 | */ | |
18c98b65 RM |
2171 | if (signr != info->si_signo) { |
2172 | info->si_signo = signr; | |
2173 | info->si_errno = 0; | |
2174 | info->si_code = SI_USER; | |
6b550f94 | 2175 | rcu_read_lock(); |
18c98b65 | 2176 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2177 | info->si_uid = from_kuid_munged(current_user_ns(), |
2178 | task_uid(current->parent)); | |
6b550f94 | 2179 | rcu_read_unlock(); |
18c98b65 RM |
2180 | } |
2181 | ||
2182 | /* If the (new) signal is now blocked, requeue it. */ | |
2183 | if (sigismember(¤t->blocked, signr)) { | |
2184 | specific_send_sig_info(signr, info, current); | |
2185 | signr = 0; | |
2186 | } | |
2187 | ||
2188 | return signr; | |
2189 | } | |
2190 | ||
1da177e4 LT |
2191 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
2192 | struct pt_regs *regs, void *cookie) | |
2193 | { | |
f6b76d4f ON |
2194 | struct sighand_struct *sighand = current->sighand; |
2195 | struct signal_struct *signal = current->signal; | |
2196 | int signr; | |
1da177e4 | 2197 | |
f784e8a7 ON |
2198 | if (unlikely(current->task_works)) |
2199 | task_work_run(); | |
72667028 | 2200 | |
0326f5a9 SD |
2201 | if (unlikely(uprobe_deny_signal())) |
2202 | return 0; | |
2203 | ||
13b1c3d4 | 2204 | /* |
5d8f72b5 ON |
2205 | * Do this once, we can't return to user-mode if freezing() == T. |
2206 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2207 | * thus do not need another check after return. | |
13b1c3d4 | 2208 | */ |
fc558a74 RW |
2209 | try_to_freeze(); |
2210 | ||
5d8f72b5 | 2211 | relock: |
f6b76d4f | 2212 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2213 | /* |
2214 | * Every stopped thread goes here after wakeup. Check to see if | |
2215 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2216 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2217 | */ | |
f6b76d4f | 2218 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2219 | int why; |
2220 | ||
2221 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2222 | why = CLD_CONTINUED; | |
2223 | else | |
2224 | why = CLD_STOPPED; | |
2225 | ||
f6b76d4f | 2226 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2227 | |
ae6d2ed7 | 2228 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2229 | |
ceb6bd67 TH |
2230 | /* |
2231 | * Notify the parent that we're continuing. This event is | |
2232 | * always per-process and doesn't make whole lot of sense | |
2233 | * for ptracers, who shouldn't consume the state via | |
2234 | * wait(2) either, but, for backward compatibility, notify | |
2235 | * the ptracer of the group leader too unless it's gonna be | |
2236 | * a duplicate. | |
2237 | */ | |
edf2ed15 | 2238 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2239 | do_notify_parent_cldstop(current, false, why); |
2240 | ||
bb3696da ON |
2241 | if (ptrace_reparented(current->group_leader)) |
2242 | do_notify_parent_cldstop(current->group_leader, | |
2243 | true, why); | |
edf2ed15 | 2244 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2245 | |
e4420551 ON |
2246 | goto relock; |
2247 | } | |
2248 | ||
1da177e4 LT |
2249 | for (;;) { |
2250 | struct k_sigaction *ka; | |
1be53963 | 2251 | |
dd1d6772 TH |
2252 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2253 | do_signal_stop(0)) | |
7bcf6a2c | 2254 | goto relock; |
1be53963 | 2255 | |
73ddff2b TH |
2256 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2257 | do_jobctl_trap(); | |
2258 | spin_unlock_irq(&sighand->siglock); | |
2259 | goto relock; | |
2260 | } | |
1da177e4 | 2261 | |
dd1d6772 | 2262 | signr = dequeue_signal(current, ¤t->blocked, info); |
7bcf6a2c | 2263 | |
dd1d6772 TH |
2264 | if (!signr) |
2265 | break; /* will return 0 */ | |
7bcf6a2c | 2266 | |
8a352418 | 2267 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
94eb22d5 | 2268 | signr = ptrace_signal(signr, info); |
dd1d6772 TH |
2269 | if (!signr) |
2270 | continue; | |
1da177e4 LT |
2271 | } |
2272 | ||
dd1d6772 TH |
2273 | ka = &sighand->action[signr-1]; |
2274 | ||
f9d4257e MH |
2275 | /* Trace actually delivered signals. */ |
2276 | trace_signal_deliver(signr, info, ka); | |
2277 | ||
1da177e4 LT |
2278 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2279 | continue; | |
2280 | if (ka->sa.sa_handler != SIG_DFL) { | |
2281 | /* Run the handler. */ | |
2282 | *return_ka = *ka; | |
2283 | ||
2284 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2285 | ka->sa.sa_handler = SIG_DFL; | |
2286 | ||
2287 | break; /* will return non-zero "signr" value */ | |
2288 | } | |
2289 | ||
2290 | /* | |
2291 | * Now we are doing the default action for this signal. | |
2292 | */ | |
2293 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2294 | continue; | |
2295 | ||
84d73786 | 2296 | /* |
0fbc26a6 | 2297 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2298 | * Container-init gets no signals it doesn't want from same |
2299 | * container. | |
2300 | * | |
2301 | * Note that if global/container-init sees a sig_kernel_only() | |
2302 | * signal here, the signal must have been generated internally | |
2303 | * or must have come from an ancestor namespace. In either | |
2304 | * case, the signal cannot be dropped. | |
84d73786 | 2305 | */ |
fae5fa44 | 2306 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2307 | !sig_kernel_only(signr)) |
1da177e4 LT |
2308 | continue; |
2309 | ||
2310 | if (sig_kernel_stop(signr)) { | |
2311 | /* | |
2312 | * The default action is to stop all threads in | |
2313 | * the thread group. The job control signals | |
2314 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2315 | * always works. Note that siglock needs to be | |
2316 | * dropped during the call to is_orphaned_pgrp() | |
2317 | * because of lock ordering with tasklist_lock. | |
2318 | * This allows an intervening SIGCONT to be posted. | |
2319 | * We need to check for that and bail out if necessary. | |
2320 | */ | |
2321 | if (signr != SIGSTOP) { | |
f6b76d4f | 2322 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2323 | |
2324 | /* signals can be posted during this window */ | |
2325 | ||
3e7cd6c4 | 2326 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2327 | goto relock; |
2328 | ||
f6b76d4f | 2329 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2330 | } |
2331 | ||
7bcf6a2c | 2332 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
2333 | /* It released the siglock. */ |
2334 | goto relock; | |
2335 | } | |
2336 | ||
2337 | /* | |
2338 | * We didn't actually stop, due to a race | |
2339 | * with SIGCONT or something like that. | |
2340 | */ | |
2341 | continue; | |
2342 | } | |
2343 | ||
f6b76d4f | 2344 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2345 | |
2346 | /* | |
2347 | * Anything else is fatal, maybe with a core dump. | |
2348 | */ | |
2349 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2350 | |
1da177e4 | 2351 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2352 | if (print_fatal_signals) |
4aaefee5 | 2353 | print_fatal_signal(info->si_signo); |
2b5faa4c | 2354 | proc_coredump_connector(current); |
1da177e4 LT |
2355 | /* |
2356 | * If it was able to dump core, this kills all | |
2357 | * other threads in the group and synchronizes with | |
2358 | * their demise. If we lost the race with another | |
2359 | * thread getting here, it set group_exit_code | |
2360 | * first and our do_group_exit call below will use | |
2361 | * that value and ignore the one we pass it. | |
2362 | */ | |
541880d9 | 2363 | do_coredump(info); |
1da177e4 LT |
2364 | } |
2365 | ||
2366 | /* | |
2367 | * Death signals, no core dump. | |
2368 | */ | |
7bcf6a2c | 2369 | do_group_exit(info->si_signo); |
1da177e4 LT |
2370 | /* NOTREACHED */ |
2371 | } | |
f6b76d4f | 2372 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2373 | return signr; |
2374 | } | |
2375 | ||
5e6292c0 | 2376 | /** |
efee984c AV |
2377 | * signal_delivered - |
2378 | * @sig: number of signal being delivered | |
2379 | * @info: siginfo_t of signal being delivered | |
2380 | * @ka: sigaction setting that chose the handler | |
2381 | * @regs: user register state | |
2382 | * @stepping: nonzero if debugger single-step or block-step in use | |
5e6292c0 MF |
2383 | * |
2384 | * This function should be called when a signal has succesfully been | |
efee984c AV |
2385 | * delivered. It updates the blocked signals accordingly (@ka->sa.sa_mask |
2386 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER | |
2387 | * is set in @ka->sa.sa_flags. Tracing is notified. | |
5e6292c0 | 2388 | */ |
efee984c AV |
2389 | void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka, |
2390 | struct pt_regs *regs, int stepping) | |
5e6292c0 MF |
2391 | { |
2392 | sigset_t blocked; | |
2393 | ||
a610d6e6 AV |
2394 | /* A signal was successfully delivered, and the |
2395 | saved sigmask was stored on the signal frame, | |
2396 | and will be restored by sigreturn. So we can | |
2397 | simply clear the restore sigmask flag. */ | |
2398 | clear_restore_sigmask(); | |
2399 | ||
5e6292c0 MF |
2400 | sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask); |
2401 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
efee984c | 2402 | sigaddset(&blocked, sig); |
5e6292c0 | 2403 | set_current_blocked(&blocked); |
efee984c | 2404 | tracehook_signal_handler(sig, info, ka, regs, stepping); |
5e6292c0 MF |
2405 | } |
2406 | ||
2ce5da17 AV |
2407 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2408 | { | |
2409 | if (failed) | |
2410 | force_sigsegv(ksig->sig, current); | |
2411 | else | |
2412 | signal_delivered(ksig->sig, &ksig->info, &ksig->ka, | |
2413 | signal_pt_regs(), stepping); | |
2414 | } | |
2415 | ||
0edceb7b ON |
2416 | /* |
2417 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2418 | * group-wide signal. Other threads should be notified now to take |
2419 | * the shared signals in @which since we will not. | |
0edceb7b | 2420 | */ |
f646e227 | 2421 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2422 | { |
f646e227 | 2423 | sigset_t retarget; |
0edceb7b ON |
2424 | struct task_struct *t; |
2425 | ||
f646e227 ON |
2426 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2427 | if (sigisemptyset(&retarget)) | |
2428 | return; | |
2429 | ||
0edceb7b ON |
2430 | t = tsk; |
2431 | while_each_thread(tsk, t) { | |
fec9993d ON |
2432 | if (t->flags & PF_EXITING) |
2433 | continue; | |
2434 | ||
2435 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2436 | continue; | |
2437 | /* Remove the signals this thread can handle. */ | |
2438 | sigandsets(&retarget, &retarget, &t->blocked); | |
2439 | ||
2440 | if (!signal_pending(t)) | |
2441 | signal_wake_up(t, 0); | |
2442 | ||
2443 | if (sigisemptyset(&retarget)) | |
2444 | break; | |
0edceb7b ON |
2445 | } |
2446 | } | |
2447 | ||
d12619b5 ON |
2448 | void exit_signals(struct task_struct *tsk) |
2449 | { | |
2450 | int group_stop = 0; | |
f646e227 | 2451 | sigset_t unblocked; |
d12619b5 | 2452 | |
77e4ef99 TH |
2453 | /* |
2454 | * @tsk is about to have PF_EXITING set - lock out users which | |
2455 | * expect stable threadgroup. | |
2456 | */ | |
2457 | threadgroup_change_begin(tsk); | |
2458 | ||
5dee1707 ON |
2459 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2460 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2461 | threadgroup_change_end(tsk); |
5dee1707 | 2462 | return; |
d12619b5 ON |
2463 | } |
2464 | ||
5dee1707 | 2465 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2466 | /* |
2467 | * From now this task is not visible for group-wide signals, | |
2468 | * see wants_signal(), do_signal_stop(). | |
2469 | */ | |
2470 | tsk->flags |= PF_EXITING; | |
77e4ef99 TH |
2471 | |
2472 | threadgroup_change_end(tsk); | |
2473 | ||
5dee1707 ON |
2474 | if (!signal_pending(tsk)) |
2475 | goto out; | |
2476 | ||
f646e227 ON |
2477 | unblocked = tsk->blocked; |
2478 | signotset(&unblocked); | |
2479 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2480 | |
a8f072c1 | 2481 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2482 | task_participate_group_stop(tsk)) |
edf2ed15 | 2483 | group_stop = CLD_STOPPED; |
5dee1707 | 2484 | out: |
d12619b5 ON |
2485 | spin_unlock_irq(&tsk->sighand->siglock); |
2486 | ||
62bcf9d9 TH |
2487 | /* |
2488 | * If group stop has completed, deliver the notification. This | |
2489 | * should always go to the real parent of the group leader. | |
2490 | */ | |
ae6d2ed7 | 2491 | if (unlikely(group_stop)) { |
d12619b5 | 2492 | read_lock(&tasklist_lock); |
62bcf9d9 | 2493 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2494 | read_unlock(&tasklist_lock); |
2495 | } | |
2496 | } | |
2497 | ||
1da177e4 LT |
2498 | EXPORT_SYMBOL(recalc_sigpending); |
2499 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2500 | EXPORT_SYMBOL(flush_signals); | |
2501 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2502 | EXPORT_SYMBOL(send_sig); |
2503 | EXPORT_SYMBOL(send_sig_info); | |
2504 | EXPORT_SYMBOL(sigprocmask); | |
2505 | EXPORT_SYMBOL(block_all_signals); | |
2506 | EXPORT_SYMBOL(unblock_all_signals); | |
2507 | ||
2508 | ||
2509 | /* | |
2510 | * System call entry points. | |
2511 | */ | |
2512 | ||
41c57892 RD |
2513 | /** |
2514 | * sys_restart_syscall - restart a system call | |
2515 | */ | |
754fe8d2 | 2516 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2517 | { |
2518 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2519 | return restart->fn(restart); | |
2520 | } | |
2521 | ||
2522 | long do_no_restart_syscall(struct restart_block *param) | |
2523 | { | |
2524 | return -EINTR; | |
2525 | } | |
2526 | ||
b182801a ON |
2527 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2528 | { | |
2529 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2530 | sigset_t newblocked; | |
2531 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2532 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2533 | retarget_shared_pending(tsk, &newblocked); |
2534 | } | |
2535 | tsk->blocked = *newset; | |
2536 | recalc_sigpending(); | |
2537 | } | |
2538 | ||
e6fa16ab ON |
2539 | /** |
2540 | * set_current_blocked - change current->blocked mask | |
2541 | * @newset: new mask | |
2542 | * | |
2543 | * It is wrong to change ->blocked directly, this helper should be used | |
2544 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2545 | */ |
77097ae5 AV |
2546 | void set_current_blocked(sigset_t *newset) |
2547 | { | |
77097ae5 | 2548 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2549 | __set_current_blocked(newset); |
77097ae5 AV |
2550 | } |
2551 | ||
2552 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2553 | { |
2554 | struct task_struct *tsk = current; | |
2555 | ||
2556 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2557 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2558 | spin_unlock_irq(&tsk->sighand->siglock); |
2559 | } | |
1da177e4 LT |
2560 | |
2561 | /* | |
2562 | * This is also useful for kernel threads that want to temporarily | |
2563 | * (or permanently) block certain signals. | |
2564 | * | |
2565 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2566 | * interface happily blocks "unblockable" signals like SIGKILL | |
2567 | * and friends. | |
2568 | */ | |
2569 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2570 | { | |
73ef4aeb ON |
2571 | struct task_struct *tsk = current; |
2572 | sigset_t newset; | |
1da177e4 | 2573 | |
73ef4aeb | 2574 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2575 | if (oldset) |
73ef4aeb | 2576 | *oldset = tsk->blocked; |
a26fd335 | 2577 | |
1da177e4 LT |
2578 | switch (how) { |
2579 | case SIG_BLOCK: | |
73ef4aeb | 2580 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2581 | break; |
2582 | case SIG_UNBLOCK: | |
702a5073 | 2583 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2584 | break; |
2585 | case SIG_SETMASK: | |
73ef4aeb | 2586 | newset = *set; |
1da177e4 LT |
2587 | break; |
2588 | default: | |
73ef4aeb | 2589 | return -EINVAL; |
1da177e4 | 2590 | } |
a26fd335 | 2591 | |
77097ae5 | 2592 | __set_current_blocked(&newset); |
73ef4aeb | 2593 | return 0; |
1da177e4 LT |
2594 | } |
2595 | ||
41c57892 RD |
2596 | /** |
2597 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2598 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2599 | * @nset: stores pending signals |
41c57892 RD |
2600 | * @oset: previous value of signal mask if non-null |
2601 | * @sigsetsize: size of sigset_t type | |
2602 | */ | |
bb7efee2 | 2603 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2604 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2605 | { |
1da177e4 | 2606 | sigset_t old_set, new_set; |
bb7efee2 | 2607 | int error; |
1da177e4 LT |
2608 | |
2609 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2610 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2611 | return -EINVAL; |
1da177e4 | 2612 | |
bb7efee2 ON |
2613 | old_set = current->blocked; |
2614 | ||
2615 | if (nset) { | |
2616 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2617 | return -EFAULT; | |
1da177e4 LT |
2618 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2619 | ||
bb7efee2 | 2620 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2621 | if (error) |
bb7efee2 ON |
2622 | return error; |
2623 | } | |
1da177e4 | 2624 | |
bb7efee2 ON |
2625 | if (oset) { |
2626 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2627 | return -EFAULT; | |
1da177e4 | 2628 | } |
bb7efee2 ON |
2629 | |
2630 | return 0; | |
1da177e4 LT |
2631 | } |
2632 | ||
322a56cb | 2633 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2634 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2635 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2636 | { |
322a56cb AV |
2637 | #ifdef __BIG_ENDIAN |
2638 | sigset_t old_set = current->blocked; | |
2639 | ||
2640 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2641 | if (sigsetsize != sizeof(sigset_t)) | |
2642 | return -EINVAL; | |
2643 | ||
2644 | if (nset) { | |
2645 | compat_sigset_t new32; | |
2646 | sigset_t new_set; | |
2647 | int error; | |
2648 | if (copy_from_user(&new32, nset, sizeof(compat_sigset_t))) | |
2649 | return -EFAULT; | |
2650 | ||
2651 | sigset_from_compat(&new_set, &new32); | |
2652 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2653 | ||
2654 | error = sigprocmask(how, &new_set, NULL); | |
2655 | if (error) | |
2656 | return error; | |
2657 | } | |
2658 | if (oset) { | |
2659 | compat_sigset_t old32; | |
2660 | sigset_to_compat(&old32, &old_set); | |
db61ec29 | 2661 | if (copy_to_user(oset, &old32, sizeof(compat_sigset_t))) |
322a56cb AV |
2662 | return -EFAULT; |
2663 | } | |
2664 | return 0; | |
2665 | #else | |
2666 | return sys_rt_sigprocmask(how, (sigset_t __user *)nset, | |
2667 | (sigset_t __user *)oset, sigsetsize); | |
2668 | #endif | |
2669 | } | |
2670 | #endif | |
1da177e4 | 2671 | |
fe9c1db2 | 2672 | static int do_sigpending(void *set, unsigned long sigsetsize) |
1da177e4 | 2673 | { |
1da177e4 | 2674 | if (sigsetsize > sizeof(sigset_t)) |
fe9c1db2 | 2675 | return -EINVAL; |
1da177e4 LT |
2676 | |
2677 | spin_lock_irq(¤t->sighand->siglock); | |
fe9c1db2 | 2678 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
2679 | ¤t->signal->shared_pending.signal); |
2680 | spin_unlock_irq(¤t->sighand->siglock); | |
2681 | ||
2682 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 AV |
2683 | sigandsets(set, ¤t->blocked, set); |
2684 | return 0; | |
5aba085e | 2685 | } |
1da177e4 | 2686 | |
41c57892 RD |
2687 | /** |
2688 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2689 | * while blocked | |
20f22ab4 | 2690 | * @uset: stores pending signals |
41c57892 RD |
2691 | * @sigsetsize: size of sigset_t type or larger |
2692 | */ | |
fe9c1db2 | 2693 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 2694 | { |
fe9c1db2 AV |
2695 | sigset_t set; |
2696 | int err = do_sigpending(&set, sigsetsize); | |
2697 | if (!err && copy_to_user(uset, &set, sigsetsize)) | |
2698 | err = -EFAULT; | |
2699 | return err; | |
2700 | } | |
2701 | ||
2702 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
2703 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
2704 | compat_size_t, sigsetsize) | |
1da177e4 | 2705 | { |
fe9c1db2 AV |
2706 | #ifdef __BIG_ENDIAN |
2707 | sigset_t set; | |
2708 | int err = do_sigpending(&set, sigsetsize); | |
2709 | if (!err) { | |
2710 | compat_sigset_t set32; | |
2711 | sigset_to_compat(&set32, &set); | |
2712 | /* we can get here only if sigsetsize <= sizeof(set) */ | |
2713 | if (copy_to_user(uset, &set32, sigsetsize)) | |
2714 | err = -EFAULT; | |
2715 | } | |
2716 | return err; | |
2717 | #else | |
2718 | return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize); | |
2719 | #endif | |
1da177e4 | 2720 | } |
fe9c1db2 | 2721 | #endif |
1da177e4 LT |
2722 | |
2723 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2724 | ||
2725 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2726 | { | |
2727 | int err; | |
2728 | ||
2729 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2730 | return -EFAULT; | |
2731 | if (from->si_code < 0) | |
2732 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2733 | ? -EFAULT : 0; | |
2734 | /* | |
2735 | * If you change siginfo_t structure, please be sure | |
2736 | * this code is fixed accordingly. | |
fba2afaa DL |
2737 | * Please remember to update the signalfd_copyinfo() function |
2738 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2739 | * It should never copy any pad contained in the structure |
2740 | * to avoid security leaks, but must copy the generic | |
2741 | * 3 ints plus the relevant union member. | |
2742 | */ | |
2743 | err = __put_user(from->si_signo, &to->si_signo); | |
2744 | err |= __put_user(from->si_errno, &to->si_errno); | |
2745 | err |= __put_user((short)from->si_code, &to->si_code); | |
2746 | switch (from->si_code & __SI_MASK) { | |
2747 | case __SI_KILL: | |
2748 | err |= __put_user(from->si_pid, &to->si_pid); | |
2749 | err |= __put_user(from->si_uid, &to->si_uid); | |
2750 | break; | |
2751 | case __SI_TIMER: | |
2752 | err |= __put_user(from->si_tid, &to->si_tid); | |
2753 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2754 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2755 | break; | |
2756 | case __SI_POLL: | |
2757 | err |= __put_user(from->si_band, &to->si_band); | |
2758 | err |= __put_user(from->si_fd, &to->si_fd); | |
2759 | break; | |
2760 | case __SI_FAULT: | |
2761 | err |= __put_user(from->si_addr, &to->si_addr); | |
2762 | #ifdef __ARCH_SI_TRAPNO | |
2763 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2764 | #endif |
2765 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2766 | /* |
a337fdac | 2767 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2768 | * so check explicitly for the right codes here. |
a337fdac AK |
2769 | */ |
2770 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2771 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2772 | #endif |
2773 | break; | |
2774 | case __SI_CHLD: | |
2775 | err |= __put_user(from->si_pid, &to->si_pid); | |
2776 | err |= __put_user(from->si_uid, &to->si_uid); | |
2777 | err |= __put_user(from->si_status, &to->si_status); | |
2778 | err |= __put_user(from->si_utime, &to->si_utime); | |
2779 | err |= __put_user(from->si_stime, &to->si_stime); | |
2780 | break; | |
2781 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2782 | case __SI_MESGQ: /* But this is */ | |
2783 | err |= __put_user(from->si_pid, &to->si_pid); | |
2784 | err |= __put_user(from->si_uid, &to->si_uid); | |
2785 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2786 | break; | |
a0727e8c WD |
2787 | #ifdef __ARCH_SIGSYS |
2788 | case __SI_SYS: | |
2789 | err |= __put_user(from->si_call_addr, &to->si_call_addr); | |
2790 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2791 | err |= __put_user(from->si_arch, &to->si_arch); | |
2792 | break; | |
2793 | #endif | |
1da177e4 LT |
2794 | default: /* this is just in case for now ... */ |
2795 | err |= __put_user(from->si_pid, &to->si_pid); | |
2796 | err |= __put_user(from->si_uid, &to->si_uid); | |
2797 | break; | |
2798 | } | |
2799 | return err; | |
2800 | } | |
2801 | ||
2802 | #endif | |
2803 | ||
943df148 ON |
2804 | /** |
2805 | * do_sigtimedwait - wait for queued signals specified in @which | |
2806 | * @which: queued signals to wait for | |
2807 | * @info: if non-null, the signal's siginfo is returned here | |
2808 | * @ts: upper bound on process time suspension | |
2809 | */ | |
2810 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info, | |
2811 | const struct timespec *ts) | |
2812 | { | |
2813 | struct task_struct *tsk = current; | |
2814 | long timeout = MAX_SCHEDULE_TIMEOUT; | |
2815 | sigset_t mask = *which; | |
2816 | int sig; | |
2817 | ||
2818 | if (ts) { | |
2819 | if (!timespec_valid(ts)) | |
2820 | return -EINVAL; | |
2821 | timeout = timespec_to_jiffies(ts); | |
2822 | /* | |
2823 | * We can be close to the next tick, add another one | |
2824 | * to ensure we will wait at least the time asked for. | |
2825 | */ | |
2826 | if (ts->tv_sec || ts->tv_nsec) | |
2827 | timeout++; | |
2828 | } | |
2829 | ||
2830 | /* | |
2831 | * Invert the set of allowed signals to get those we want to block. | |
2832 | */ | |
2833 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2834 | signotset(&mask); | |
2835 | ||
2836 | spin_lock_irq(&tsk->sighand->siglock); | |
2837 | sig = dequeue_signal(tsk, &mask, info); | |
2838 | if (!sig && timeout) { | |
2839 | /* | |
2840 | * None ready, temporarily unblock those we're interested | |
2841 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2842 | * they arrive. Unblocking is always fine, we can avoid |
2843 | * set_current_blocked(). | |
943df148 ON |
2844 | */ |
2845 | tsk->real_blocked = tsk->blocked; | |
2846 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2847 | recalc_sigpending(); | |
2848 | spin_unlock_irq(&tsk->sighand->siglock); | |
2849 | ||
2850 | timeout = schedule_timeout_interruptible(timeout); | |
2851 | ||
2852 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2853 | __set_task_blocked(tsk, &tsk->real_blocked); |
943df148 | 2854 | siginitset(&tsk->real_blocked, 0); |
b182801a | 2855 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2856 | } |
2857 | spin_unlock_irq(&tsk->sighand->siglock); | |
2858 | ||
2859 | if (sig) | |
2860 | return sig; | |
2861 | return timeout ? -EINTR : -EAGAIN; | |
2862 | } | |
2863 | ||
41c57892 RD |
2864 | /** |
2865 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2866 | * in @uthese | |
2867 | * @uthese: queued signals to wait for | |
2868 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2869 | * @uts: upper bound on process time suspension | |
2870 | * @sigsetsize: size of sigset_t type | |
2871 | */ | |
17da2bd9 HC |
2872 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2873 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2874 | size_t, sigsetsize) | |
1da177e4 | 2875 | { |
1da177e4 LT |
2876 | sigset_t these; |
2877 | struct timespec ts; | |
2878 | siginfo_t info; | |
943df148 | 2879 | int ret; |
1da177e4 LT |
2880 | |
2881 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2882 | if (sigsetsize != sizeof(sigset_t)) | |
2883 | return -EINVAL; | |
2884 | ||
2885 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2886 | return -EFAULT; | |
5aba085e | 2887 | |
1da177e4 LT |
2888 | if (uts) { |
2889 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2890 | return -EFAULT; | |
1da177e4 LT |
2891 | } |
2892 | ||
943df148 | 2893 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2894 | |
943df148 ON |
2895 | if (ret > 0 && uinfo) { |
2896 | if (copy_siginfo_to_user(uinfo, &info)) | |
2897 | ret = -EFAULT; | |
1da177e4 LT |
2898 | } |
2899 | ||
2900 | return ret; | |
2901 | } | |
2902 | ||
41c57892 RD |
2903 | /** |
2904 | * sys_kill - send a signal to a process | |
2905 | * @pid: the PID of the process | |
2906 | * @sig: signal to be sent | |
2907 | */ | |
17da2bd9 | 2908 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2909 | { |
2910 | struct siginfo info; | |
2911 | ||
2912 | info.si_signo = sig; | |
2913 | info.si_errno = 0; | |
2914 | info.si_code = SI_USER; | |
b488893a | 2915 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2916 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2917 | |
2918 | return kill_something_info(sig, &info, pid); | |
2919 | } | |
2920 | ||
30b4ae8a TG |
2921 | static int |
2922 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2923 | { |
1da177e4 | 2924 | struct task_struct *p; |
30b4ae8a | 2925 | int error = -ESRCH; |
1da177e4 | 2926 | |
3547ff3a | 2927 | rcu_read_lock(); |
228ebcbe | 2928 | p = find_task_by_vpid(pid); |
b488893a | 2929 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2930 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2931 | /* |
2932 | * The null signal is a permissions and process existence | |
2933 | * probe. No signal is actually delivered. | |
2934 | */ | |
4a30debf ON |
2935 | if (!error && sig) { |
2936 | error = do_send_sig_info(sig, info, p, false); | |
2937 | /* | |
2938 | * If lock_task_sighand() failed we pretend the task | |
2939 | * dies after receiving the signal. The window is tiny, | |
2940 | * and the signal is private anyway. | |
2941 | */ | |
2942 | if (unlikely(error == -ESRCH)) | |
2943 | error = 0; | |
1da177e4 LT |
2944 | } |
2945 | } | |
3547ff3a | 2946 | rcu_read_unlock(); |
6dd69f10 | 2947 | |
1da177e4 LT |
2948 | return error; |
2949 | } | |
2950 | ||
30b4ae8a TG |
2951 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2952 | { | |
b9e146d8 | 2953 | struct siginfo info = {}; |
30b4ae8a TG |
2954 | |
2955 | info.si_signo = sig; | |
2956 | info.si_errno = 0; | |
2957 | info.si_code = SI_TKILL; | |
2958 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 2959 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
2960 | |
2961 | return do_send_specific(tgid, pid, sig, &info); | |
2962 | } | |
2963 | ||
6dd69f10 VL |
2964 | /** |
2965 | * sys_tgkill - send signal to one specific thread | |
2966 | * @tgid: the thread group ID of the thread | |
2967 | * @pid: the PID of the thread | |
2968 | * @sig: signal to be sent | |
2969 | * | |
72fd4a35 | 2970 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2971 | * exists but it's not belonging to the target process anymore. This |
2972 | * method solves the problem of threads exiting and PIDs getting reused. | |
2973 | */ | |
a5f8fa9e | 2974 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2975 | { |
2976 | /* This is only valid for single tasks */ | |
2977 | if (pid <= 0 || tgid <= 0) | |
2978 | return -EINVAL; | |
2979 | ||
2980 | return do_tkill(tgid, pid, sig); | |
2981 | } | |
2982 | ||
41c57892 RD |
2983 | /** |
2984 | * sys_tkill - send signal to one specific task | |
2985 | * @pid: the PID of the task | |
2986 | * @sig: signal to be sent | |
2987 | * | |
1da177e4 LT |
2988 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2989 | */ | |
a5f8fa9e | 2990 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2991 | { |
1da177e4 LT |
2992 | /* This is only valid for single tasks */ |
2993 | if (pid <= 0) | |
2994 | return -EINVAL; | |
2995 | ||
6dd69f10 | 2996 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2997 | } |
2998 | ||
75907d4d AV |
2999 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) |
3000 | { | |
3001 | /* Not even root can pretend to send signals from the kernel. | |
3002 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
3003 | */ | |
66dd34ad AV |
3004 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3005 | (task_pid_vnr(current) != pid)) { | |
75907d4d AV |
3006 | /* We used to allow any < 0 si_code */ |
3007 | WARN_ON_ONCE(info->si_code < 0); | |
3008 | return -EPERM; | |
3009 | } | |
3010 | info->si_signo = sig; | |
3011 | ||
3012 | /* POSIX.1b doesn't mention process groups. */ | |
3013 | return kill_proc_info(sig, info, pid); | |
3014 | } | |
3015 | ||
41c57892 RD |
3016 | /** |
3017 | * sys_rt_sigqueueinfo - send signal information to a signal | |
3018 | * @pid: the PID of the thread | |
3019 | * @sig: signal to be sent | |
3020 | * @uinfo: signal info to be sent | |
3021 | */ | |
a5f8fa9e HC |
3022 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
3023 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
3024 | { |
3025 | siginfo_t info; | |
1da177e4 LT |
3026 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) |
3027 | return -EFAULT; | |
75907d4d AV |
3028 | return do_rt_sigqueueinfo(pid, sig, &info); |
3029 | } | |
1da177e4 | 3030 | |
75907d4d | 3031 | #ifdef CONFIG_COMPAT |
75907d4d AV |
3032 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
3033 | compat_pid_t, pid, | |
3034 | int, sig, | |
3035 | struct compat_siginfo __user *, uinfo) | |
3036 | { | |
3037 | siginfo_t info; | |
3038 | int ret = copy_siginfo_from_user32(&info, uinfo); | |
3039 | if (unlikely(ret)) | |
3040 | return ret; | |
3041 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 3042 | } |
75907d4d | 3043 | #endif |
1da177e4 | 3044 | |
9aae8fc0 | 3045 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
62ab4505 TG |
3046 | { |
3047 | /* This is only valid for single tasks */ | |
3048 | if (pid <= 0 || tgid <= 0) | |
3049 | return -EINVAL; | |
3050 | ||
3051 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3052 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3053 | */ | |
66dd34ad AV |
3054 | if (((info->si_code >= 0 || info->si_code == SI_TKILL)) && |
3055 | (task_pid_vnr(current) != pid)) { | |
da48524e JT |
3056 | /* We used to allow any < 0 si_code */ |
3057 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 3058 | return -EPERM; |
da48524e | 3059 | } |
62ab4505 TG |
3060 | info->si_signo = sig; |
3061 | ||
3062 | return do_send_specific(tgid, pid, sig, info); | |
3063 | } | |
3064 | ||
3065 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3066 | siginfo_t __user *, uinfo) | |
3067 | { | |
3068 | siginfo_t info; | |
3069 | ||
3070 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3071 | return -EFAULT; | |
3072 | ||
3073 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3074 | } | |
3075 | ||
9aae8fc0 AV |
3076 | #ifdef CONFIG_COMPAT |
3077 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3078 | compat_pid_t, tgid, | |
3079 | compat_pid_t, pid, | |
3080 | int, sig, | |
3081 | struct compat_siginfo __user *, uinfo) | |
3082 | { | |
3083 | siginfo_t info; | |
3084 | ||
3085 | if (copy_siginfo_from_user32(&info, uinfo)) | |
3086 | return -EFAULT; | |
3087 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3088 | } | |
3089 | #endif | |
3090 | ||
88531f72 | 3091 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3092 | { |
93585eea | 3093 | struct task_struct *t = current; |
1da177e4 | 3094 | struct k_sigaction *k; |
71fabd5e | 3095 | sigset_t mask; |
1da177e4 | 3096 | |
7ed20e1a | 3097 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3098 | return -EINVAL; |
3099 | ||
93585eea | 3100 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
3101 | |
3102 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
3103 | if (oact) |
3104 | *oact = *k; | |
3105 | ||
3106 | if (act) { | |
9ac95f2f ON |
3107 | sigdelsetmask(&act->sa.sa_mask, |
3108 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3109 | *k = *act; |
1da177e4 LT |
3110 | /* |
3111 | * POSIX 3.3.1.3: | |
3112 | * "Setting a signal action to SIG_IGN for a signal that is | |
3113 | * pending shall cause the pending signal to be discarded, | |
3114 | * whether or not it is blocked." | |
3115 | * | |
3116 | * "Setting a signal action to SIG_DFL for a signal that is | |
3117 | * pending and whose default action is to ignore the signal | |
3118 | * (for example, SIGCHLD), shall cause the pending signal to | |
3119 | * be discarded, whether or not it is blocked" | |
3120 | */ | |
35de254d | 3121 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
3122 | sigemptyset(&mask); |
3123 | sigaddset(&mask, sig); | |
3124 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 3125 | do { |
71fabd5e | 3126 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
3127 | t = next_thread(t); |
3128 | } while (t != current); | |
1da177e4 | 3129 | } |
1da177e4 LT |
3130 | } |
3131 | ||
3132 | spin_unlock_irq(¤t->sighand->siglock); | |
3133 | return 0; | |
3134 | } | |
3135 | ||
e9b04b5b | 3136 | static int |
1da177e4 LT |
3137 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) |
3138 | { | |
3139 | stack_t oss; | |
3140 | int error; | |
3141 | ||
0083fc2c LT |
3142 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
3143 | oss.ss_size = current->sas_ss_size; | |
3144 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
3145 | |
3146 | if (uss) { | |
3147 | void __user *ss_sp; | |
3148 | size_t ss_size; | |
3149 | int ss_flags; | |
3150 | ||
3151 | error = -EFAULT; | |
0dd8486b LT |
3152 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
3153 | goto out; | |
3154 | error = __get_user(ss_sp, &uss->ss_sp) | | |
3155 | __get_user(ss_flags, &uss->ss_flags) | | |
3156 | __get_user(ss_size, &uss->ss_size); | |
3157 | if (error) | |
1da177e4 LT |
3158 | goto out; |
3159 | ||
3160 | error = -EPERM; | |
3161 | if (on_sig_stack(sp)) | |
3162 | goto out; | |
3163 | ||
3164 | error = -EINVAL; | |
3165 | /* | |
5aba085e | 3166 | * Note - this code used to test ss_flags incorrectly: |
1da177e4 LT |
3167 | * old code may have been written using ss_flags==0 |
3168 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
3169 | * way that worked) - this fix preserves that older | |
5aba085e | 3170 | * mechanism. |
1da177e4 LT |
3171 | */ |
3172 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
3173 | goto out; | |
3174 | ||
3175 | if (ss_flags == SS_DISABLE) { | |
3176 | ss_size = 0; | |
3177 | ss_sp = NULL; | |
3178 | } else { | |
3179 | error = -ENOMEM; | |
3180 | if (ss_size < MINSIGSTKSZ) | |
3181 | goto out; | |
3182 | } | |
3183 | ||
3184 | current->sas_ss_sp = (unsigned long) ss_sp; | |
3185 | current->sas_ss_size = ss_size; | |
3186 | } | |
3187 | ||
0083fc2c | 3188 | error = 0; |
1da177e4 LT |
3189 | if (uoss) { |
3190 | error = -EFAULT; | |
0083fc2c | 3191 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 3192 | goto out; |
0083fc2c LT |
3193 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
3194 | __put_user(oss.ss_size, &uoss->ss_size) | | |
3195 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
3196 | } |
3197 | ||
1da177e4 LT |
3198 | out: |
3199 | return error; | |
3200 | } | |
6bf9adfc AV |
3201 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3202 | { | |
3203 | return do_sigaltstack(uss, uoss, current_user_stack_pointer()); | |
3204 | } | |
1da177e4 | 3205 | |
5c49574f AV |
3206 | int restore_altstack(const stack_t __user *uss) |
3207 | { | |
3208 | int err = do_sigaltstack(uss, NULL, current_user_stack_pointer()); | |
3209 | /* squash all but EFAULT for now */ | |
3210 | return err == -EFAULT ? err : 0; | |
3211 | } | |
3212 | ||
c40702c4 AV |
3213 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3214 | { | |
3215 | struct task_struct *t = current; | |
3216 | return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | | |
3217 | __put_user(sas_ss_flags(sp), &uss->ss_flags) | | |
3218 | __put_user(t->sas_ss_size, &uss->ss_size); | |
3219 | } | |
3220 | ||
90268439 | 3221 | #ifdef CONFIG_COMPAT |
90228fc1 AV |
3222 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
3223 | const compat_stack_t __user *, uss_ptr, | |
3224 | compat_stack_t __user *, uoss_ptr) | |
90268439 AV |
3225 | { |
3226 | stack_t uss, uoss; | |
3227 | int ret; | |
3228 | mm_segment_t seg; | |
3229 | ||
3230 | if (uss_ptr) { | |
3231 | compat_stack_t uss32; | |
3232 | ||
3233 | memset(&uss, 0, sizeof(stack_t)); | |
3234 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) | |
3235 | return -EFAULT; | |
3236 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
3237 | uss.ss_flags = uss32.ss_flags; | |
3238 | uss.ss_size = uss32.ss_size; | |
3239 | } | |
3240 | seg = get_fs(); | |
3241 | set_fs(KERNEL_DS); | |
3242 | ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), | |
3243 | (stack_t __force __user *) &uoss, | |
3244 | compat_user_stack_pointer()); | |
3245 | set_fs(seg); | |
3246 | if (ret >= 0 && uoss_ptr) { | |
3247 | if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) || | |
3248 | __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) || | |
3249 | __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) || | |
3250 | __put_user(uoss.ss_size, &uoss_ptr->ss_size)) | |
3251 | ret = -EFAULT; | |
3252 | } | |
3253 | return ret; | |
3254 | } | |
3255 | ||
3256 | int compat_restore_altstack(const compat_stack_t __user *uss) | |
3257 | { | |
3258 | int err = compat_sys_sigaltstack(uss, NULL); | |
3259 | /* squash all but -EFAULT for now */ | |
3260 | return err == -EFAULT ? err : 0; | |
3261 | } | |
c40702c4 AV |
3262 | |
3263 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
3264 | { | |
3265 | struct task_struct *t = current; | |
3266 | return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) | | |
3267 | __put_user(sas_ss_flags(sp), &uss->ss_flags) | | |
3268 | __put_user(t->sas_ss_size, &uss->ss_size); | |
3269 | } | |
90268439 | 3270 | #endif |
1da177e4 LT |
3271 | |
3272 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3273 | ||
41c57892 RD |
3274 | /** |
3275 | * sys_sigpending - examine pending signals | |
3276 | * @set: where mask of pending signal is returned | |
3277 | */ | |
b290ebe2 | 3278 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 | 3279 | { |
fe9c1db2 | 3280 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); |
1da177e4 LT |
3281 | } |
3282 | ||
3283 | #endif | |
3284 | ||
3285 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3286 | /** |
3287 | * sys_sigprocmask - examine and change blocked signals | |
3288 | * @how: whether to add, remove, or set signals | |
b013c399 | 3289 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3290 | * @oset: previous value of signal mask if non-null |
3291 | * | |
5aba085e RD |
3292 | * Some platforms have their own version with special arguments; |
3293 | * others support only sys_rt_sigprocmask. | |
3294 | */ | |
1da177e4 | 3295 | |
b013c399 | 3296 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3297 | old_sigset_t __user *, oset) |
1da177e4 | 3298 | { |
1da177e4 | 3299 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3300 | sigset_t new_blocked; |
1da177e4 | 3301 | |
b013c399 | 3302 | old_set = current->blocked.sig[0]; |
1da177e4 | 3303 | |
b013c399 ON |
3304 | if (nset) { |
3305 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3306 | return -EFAULT; | |
1da177e4 | 3307 | |
2e4f7c77 | 3308 | new_blocked = current->blocked; |
1da177e4 | 3309 | |
1da177e4 | 3310 | switch (how) { |
1da177e4 | 3311 | case SIG_BLOCK: |
2e4f7c77 | 3312 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3313 | break; |
3314 | case SIG_UNBLOCK: | |
2e4f7c77 | 3315 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3316 | break; |
3317 | case SIG_SETMASK: | |
2e4f7c77 | 3318 | new_blocked.sig[0] = new_set; |
1da177e4 | 3319 | break; |
2e4f7c77 ON |
3320 | default: |
3321 | return -EINVAL; | |
1da177e4 LT |
3322 | } |
3323 | ||
0c4a8423 | 3324 | set_current_blocked(&new_blocked); |
b013c399 ON |
3325 | } |
3326 | ||
3327 | if (oset) { | |
1da177e4 | 3328 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3329 | return -EFAULT; |
1da177e4 | 3330 | } |
b013c399 ON |
3331 | |
3332 | return 0; | |
1da177e4 LT |
3333 | } |
3334 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3335 | ||
eaca6eae | 3336 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
3337 | /** |
3338 | * sys_rt_sigaction - alter an action taken by a process | |
3339 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3340 | * @act: new sigaction |
3341 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3342 | * @sigsetsize: size of sigset_t type |
3343 | */ | |
d4e82042 HC |
3344 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3345 | const struct sigaction __user *, act, | |
3346 | struct sigaction __user *, oact, | |
3347 | size_t, sigsetsize) | |
1da177e4 LT |
3348 | { |
3349 | struct k_sigaction new_sa, old_sa; | |
3350 | int ret = -EINVAL; | |
3351 | ||
3352 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3353 | if (sigsetsize != sizeof(sigset_t)) | |
3354 | goto out; | |
3355 | ||
3356 | if (act) { | |
3357 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3358 | return -EFAULT; | |
3359 | } | |
3360 | ||
3361 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3362 | ||
3363 | if (!ret && oact) { | |
3364 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3365 | return -EFAULT; | |
3366 | } | |
3367 | out: | |
3368 | return ret; | |
3369 | } | |
08d32fe5 | 3370 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
3371 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3372 | const struct compat_sigaction __user *, act, | |
3373 | struct compat_sigaction __user *, oact, | |
3374 | compat_size_t, sigsetsize) | |
3375 | { | |
3376 | struct k_sigaction new_ka, old_ka; | |
3377 | compat_sigset_t mask; | |
3378 | #ifdef __ARCH_HAS_SA_RESTORER | |
3379 | compat_uptr_t restorer; | |
3380 | #endif | |
3381 | int ret; | |
3382 | ||
3383 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3384 | if (sigsetsize != sizeof(compat_sigset_t)) | |
3385 | return -EINVAL; | |
3386 | ||
3387 | if (act) { | |
3388 | compat_uptr_t handler; | |
3389 | ret = get_user(handler, &act->sa_handler); | |
3390 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3391 | #ifdef __ARCH_HAS_SA_RESTORER | |
3392 | ret |= get_user(restorer, &act->sa_restorer); | |
3393 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3394 | #endif | |
3395 | ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask)); | |
3396 | ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags); | |
3397 | if (ret) | |
3398 | return -EFAULT; | |
3399 | sigset_from_compat(&new_ka.sa.sa_mask, &mask); | |
3400 | } | |
3401 | ||
3402 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3403 | if (!ret && oact) { | |
3404 | sigset_to_compat(&mask, &old_ka.sa.sa_mask); | |
3405 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3406 | &oact->sa_handler); | |
3407 | ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask)); | |
3408 | ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags); | |
3409 | #ifdef __ARCH_HAS_SA_RESTORER | |
3410 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3411 | &oact->sa_restorer); | |
3412 | #endif | |
3413 | } | |
3414 | return ret; | |
3415 | } | |
3416 | #endif | |
eaca6eae | 3417 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 3418 | |
495dfbf7 AV |
3419 | #ifdef CONFIG_OLD_SIGACTION |
3420 | SYSCALL_DEFINE3(sigaction, int, sig, | |
3421 | const struct old_sigaction __user *, act, | |
3422 | struct old_sigaction __user *, oact) | |
3423 | { | |
3424 | struct k_sigaction new_ka, old_ka; | |
3425 | int ret; | |
3426 | ||
3427 | if (act) { | |
3428 | old_sigset_t mask; | |
3429 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3430 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
3431 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
3432 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3433 | __get_user(mask, &act->sa_mask)) | |
3434 | return -EFAULT; | |
3435 | #ifdef __ARCH_HAS_KA_RESTORER | |
3436 | new_ka.ka_restorer = NULL; | |
3437 | #endif | |
3438 | siginitset(&new_ka.sa.sa_mask, mask); | |
3439 | } | |
3440 | ||
3441 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3442 | ||
3443 | if (!ret && oact) { | |
3444 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3445 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
3446 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
3447 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3448 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3449 | return -EFAULT; | |
3450 | } | |
3451 | ||
3452 | return ret; | |
3453 | } | |
3454 | #endif | |
3455 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
3456 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
3457 | const struct compat_old_sigaction __user *, act, | |
3458 | struct compat_old_sigaction __user *, oact) | |
3459 | { | |
3460 | struct k_sigaction new_ka, old_ka; | |
3461 | int ret; | |
3462 | compat_old_sigset_t mask; | |
3463 | compat_uptr_t handler, restorer; | |
3464 | ||
3465 | if (act) { | |
3466 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3467 | __get_user(handler, &act->sa_handler) || | |
3468 | __get_user(restorer, &act->sa_restorer) || | |
3469 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3470 | __get_user(mask, &act->sa_mask)) | |
3471 | return -EFAULT; | |
3472 | ||
3473 | #ifdef __ARCH_HAS_KA_RESTORER | |
3474 | new_ka.ka_restorer = NULL; | |
3475 | #endif | |
3476 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3477 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3478 | siginitset(&new_ka.sa.sa_mask, mask); | |
3479 | } | |
3480 | ||
3481 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3482 | ||
3483 | if (!ret && oact) { | |
3484 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3485 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3486 | &oact->sa_handler) || | |
3487 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3488 | &oact->sa_restorer) || | |
3489 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3490 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3491 | return -EFAULT; | |
3492 | } | |
3493 | return ret; | |
3494 | } | |
3495 | #endif | |
1da177e4 LT |
3496 | |
3497 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
3498 | ||
3499 | /* | |
3500 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3501 | */ | |
a5f8fa9e | 3502 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3503 | { |
3504 | /* SMP safe */ | |
3505 | return current->blocked.sig[0]; | |
3506 | } | |
3507 | ||
a5f8fa9e | 3508 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3509 | { |
c1095c6d ON |
3510 | int old = current->blocked.sig[0]; |
3511 | sigset_t newset; | |
1da177e4 | 3512 | |
5ba53ff6 | 3513 | siginitset(&newset, newmask); |
c1095c6d | 3514 | set_current_blocked(&newset); |
1da177e4 LT |
3515 | |
3516 | return old; | |
3517 | } | |
3518 | #endif /* __ARCH_WANT_SGETMASK */ | |
3519 | ||
3520 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3521 | /* | |
3522 | * For backwards compatibility. Functionality superseded by sigaction. | |
3523 | */ | |
a5f8fa9e | 3524 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3525 | { |
3526 | struct k_sigaction new_sa, old_sa; | |
3527 | int ret; | |
3528 | ||
3529 | new_sa.sa.sa_handler = handler; | |
3530 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3531 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3532 | |
3533 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3534 | ||
3535 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3536 | } | |
3537 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3538 | ||
3539 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3540 | ||
a5f8fa9e | 3541 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3542 | { |
d92fcf05 ON |
3543 | while (!signal_pending(current)) { |
3544 | current->state = TASK_INTERRUPTIBLE; | |
3545 | schedule(); | |
3546 | } | |
1da177e4 LT |
3547 | return -ERESTARTNOHAND; |
3548 | } | |
3549 | ||
3550 | #endif | |
3551 | ||
68f3f16d AV |
3552 | int sigsuspend(sigset_t *set) |
3553 | { | |
68f3f16d AV |
3554 | current->saved_sigmask = current->blocked; |
3555 | set_current_blocked(set); | |
3556 | ||
3557 | current->state = TASK_INTERRUPTIBLE; | |
3558 | schedule(); | |
3559 | set_restore_sigmask(); | |
3560 | return -ERESTARTNOHAND; | |
3561 | } | |
68f3f16d | 3562 | |
41c57892 RD |
3563 | /** |
3564 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3565 | * @unewset value until a signal is received | |
3566 | * @unewset: new signal mask value | |
3567 | * @sigsetsize: size of sigset_t type | |
3568 | */ | |
d4e82042 | 3569 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3570 | { |
3571 | sigset_t newset; | |
3572 | ||
3573 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3574 | if (sigsetsize != sizeof(sigset_t)) | |
3575 | return -EINVAL; | |
3576 | ||
3577 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3578 | return -EFAULT; | |
68f3f16d | 3579 | return sigsuspend(&newset); |
150256d8 | 3580 | } |
ad4b65a4 AV |
3581 | |
3582 | #ifdef CONFIG_COMPAT | |
3583 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
3584 | { | |
3585 | #ifdef __BIG_ENDIAN | |
3586 | sigset_t newset; | |
3587 | compat_sigset_t newset32; | |
3588 | ||
3589 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3590 | if (sigsetsize != sizeof(sigset_t)) | |
3591 | return -EINVAL; | |
3592 | ||
3593 | if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t))) | |
3594 | return -EFAULT; | |
3595 | sigset_from_compat(&newset, &newset32); | |
3596 | return sigsuspend(&newset); | |
3597 | #else | |
3598 | /* on little-endian bitmaps don't care about granularity */ | |
3599 | return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize); | |
3600 | #endif | |
3601 | } | |
3602 | #endif | |
150256d8 | 3603 | |
0a0e8cdf AV |
3604 | #ifdef CONFIG_OLD_SIGSUSPEND |
3605 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
3606 | { | |
3607 | sigset_t blocked; | |
3608 | siginitset(&blocked, mask); | |
3609 | return sigsuspend(&blocked); | |
3610 | } | |
3611 | #endif | |
3612 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
3613 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
3614 | { | |
3615 | sigset_t blocked; | |
3616 | siginitset(&blocked, mask); | |
3617 | return sigsuspend(&blocked); | |
3618 | } | |
3619 | #endif | |
150256d8 | 3620 | |
f269fdd1 DH |
3621 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
3622 | { | |
3623 | return NULL; | |
3624 | } | |
3625 | ||
1da177e4 LT |
3626 | void __init signals_init(void) |
3627 | { | |
0a31bd5f | 3628 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3629 | } |
67fc4e0c JW |
3630 | |
3631 | #ifdef CONFIG_KGDB_KDB | |
3632 | #include <linux/kdb.h> | |
3633 | /* | |
3634 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3635 | * signal internals. This function checks if the required locks are | |
3636 | * available before calling the main signal code, to avoid kdb | |
3637 | * deadlocks. | |
3638 | */ | |
3639 | void | |
3640 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3641 | { | |
3642 | static struct task_struct *kdb_prev_t; | |
3643 | int sig, new_t; | |
3644 | if (!spin_trylock(&t->sighand->siglock)) { | |
3645 | kdb_printf("Can't do kill command now.\n" | |
3646 | "The sigmask lock is held somewhere else in " | |
3647 | "kernel, try again later\n"); | |
3648 | return; | |
3649 | } | |
3650 | spin_unlock(&t->sighand->siglock); | |
3651 | new_t = kdb_prev_t != t; | |
3652 | kdb_prev_t = t; | |
3653 | if (t->state != TASK_RUNNING && new_t) { | |
3654 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3655 | "kdb risks deadlock\n" | |
3656 | "on the run queue locks. " | |
3657 | "The signal has _not_ been sent.\n" | |
3658 | "Reissue the kill command if you want to risk " | |
3659 | "the deadlock.\n"); | |
3660 | return; | |
3661 | } | |
3662 | sig = info->si_signo; | |
3663 | if (send_sig_info(sig, info, t)) | |
3664 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3665 | sig, t->pid); | |
3666 | else | |
3667 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3668 | } | |
3669 | #endif /* CONFIG_KGDB_KDB */ |