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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 | 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> | |
20 | #include <linux/security.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/ptrace.h> | |
7ed20e1a | 23 | #include <linux/signal.h> |
fba2afaa | 24 | #include <linux/signalfd.h> |
f84d49b2 | 25 | #include <linux/ratelimit.h> |
35de254d | 26 | #include <linux/tracehook.h> |
c59ede7b | 27 | #include <linux/capability.h> |
7dfb7103 | 28 | #include <linux/freezer.h> |
84d73786 SB |
29 | #include <linux/pid_namespace.h> |
30 | #include <linux/nsproxy.h> | |
6b550f94 | 31 | #include <linux/user_namespace.h> |
d1eb650f MH |
32 | #define CREATE_TRACE_POINTS |
33 | #include <trace/events/signal.h> | |
84d73786 | 34 | |
1da177e4 LT |
35 | #include <asm/param.h> |
36 | #include <asm/uaccess.h> | |
37 | #include <asm/unistd.h> | |
38 | #include <asm/siginfo.h> | |
d550bbd4 | 39 | #include <asm/cacheflush.h> |
e1396065 | 40 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
41 | |
42 | /* | |
43 | * SLAB caches for signal bits. | |
44 | */ | |
45 | ||
e18b890b | 46 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 47 | |
f84d49b2 NO |
48 | int print_fatal_signals __read_mostly; |
49 | ||
35de254d | 50 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 51 | { |
35de254d RM |
52 | return t->sighand->action[sig - 1].sa.sa_handler; |
53 | } | |
93585eea | 54 | |
35de254d RM |
55 | static int sig_handler_ignored(void __user *handler, int sig) |
56 | { | |
93585eea | 57 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
58 | return handler == SIG_IGN || |
59 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
60 | } | |
1da177e4 | 61 | |
def8cf72 | 62 | static int sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 63 | { |
35de254d | 64 | void __user *handler; |
1da177e4 | 65 | |
f008faff ON |
66 | handler = sig_handler(t, sig); |
67 | ||
68 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
def8cf72 | 69 | handler == SIG_DFL && !force) |
f008faff ON |
70 | return 1; |
71 | ||
72 | return sig_handler_ignored(handler, sig); | |
73 | } | |
74 | ||
def8cf72 | 75 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 76 | { |
1da177e4 LT |
77 | /* |
78 | * Blocked signals are never ignored, since the | |
79 | * signal handler may change by the time it is | |
80 | * unblocked. | |
81 | */ | |
325d22df | 82 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
83 | return 0; |
84 | ||
def8cf72 | 85 | if (!sig_task_ignored(t, sig, force)) |
35de254d RM |
86 | return 0; |
87 | ||
88 | /* | |
89 | * Tracers may want to know about even ignored signals. | |
90 | */ | |
a288eecc | 91 | return !t->ptrace; |
1da177e4 LT |
92 | } |
93 | ||
94 | /* | |
95 | * Re-calculate pending state from the set of locally pending | |
96 | * signals, globally pending signals, and blocked signals. | |
97 | */ | |
98 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
99 | { | |
100 | unsigned long ready; | |
101 | long i; | |
102 | ||
103 | switch (_NSIG_WORDS) { | |
104 | default: | |
105 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
106 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
107 | break; | |
108 | ||
109 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
110 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
111 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
112 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
113 | break; | |
114 | ||
115 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
116 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
117 | break; | |
118 | ||
119 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
120 | } | |
121 | return ready != 0; | |
122 | } | |
123 | ||
124 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
125 | ||
7bb44ade | 126 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 127 | { |
3759a0d9 | 128 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 129 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 130 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 131 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
132 | return 1; |
133 | } | |
b74d0deb RM |
134 | /* |
135 | * We must never clear the flag in another thread, or in current | |
136 | * when it's possible the current syscall is returning -ERESTART*. | |
137 | * So we don't clear it here, and only callers who know they should do. | |
138 | */ | |
7bb44ade RM |
139 | return 0; |
140 | } | |
141 | ||
142 | /* | |
143 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
144 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
145 | */ | |
146 | void recalc_sigpending_and_wake(struct task_struct *t) | |
147 | { | |
148 | if (recalc_sigpending_tsk(t)) | |
149 | signal_wake_up(t, 0); | |
1da177e4 LT |
150 | } |
151 | ||
152 | void recalc_sigpending(void) | |
153 | { | |
dd1d6772 | 154 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
155 | clear_thread_flag(TIF_SIGPENDING); |
156 | ||
1da177e4 LT |
157 | } |
158 | ||
159 | /* Given the mask, find the first available signal that should be serviced. */ | |
160 | ||
a27341cd LT |
161 | #define SYNCHRONOUS_MASK \ |
162 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
163 | sigmask(SIGTRAP) | sigmask(SIGFPE)) | |
164 | ||
fba2afaa | 165 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
166 | { |
167 | unsigned long i, *s, *m, x; | |
168 | int sig = 0; | |
f84d49b2 | 169 | |
1da177e4 LT |
170 | s = pending->signal.sig; |
171 | m = mask->sig; | |
a27341cd LT |
172 | |
173 | /* | |
174 | * Handle the first word specially: it contains the | |
175 | * synchronous signals that need to be dequeued first. | |
176 | */ | |
177 | x = *s &~ *m; | |
178 | if (x) { | |
179 | if (x & SYNCHRONOUS_MASK) | |
180 | x &= SYNCHRONOUS_MASK; | |
181 | sig = ffz(~x) + 1; | |
182 | return sig; | |
183 | } | |
184 | ||
1da177e4 LT |
185 | switch (_NSIG_WORDS) { |
186 | default: | |
a27341cd LT |
187 | for (i = 1; i < _NSIG_WORDS; ++i) { |
188 | x = *++s &~ *++m; | |
189 | if (!x) | |
190 | continue; | |
191 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
192 | break; | |
193 | } | |
1da177e4 LT |
194 | break; |
195 | ||
a27341cd LT |
196 | case 2: |
197 | x = s[1] &~ m[1]; | |
198 | if (!x) | |
1da177e4 | 199 | break; |
a27341cd | 200 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
201 | break; |
202 | ||
a27341cd LT |
203 | case 1: |
204 | /* Nothing to do */ | |
1da177e4 LT |
205 | break; |
206 | } | |
f84d49b2 | 207 | |
1da177e4 LT |
208 | return sig; |
209 | } | |
210 | ||
f84d49b2 NO |
211 | static inline void print_dropped_signal(int sig) |
212 | { | |
213 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
214 | ||
215 | if (!print_fatal_signals) | |
216 | return; | |
217 | ||
218 | if (!__ratelimit(&ratelimit_state)) | |
219 | return; | |
220 | ||
221 | printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", | |
222 | current->comm, current->pid, sig); | |
223 | } | |
224 | ||
d79fdd6d | 225 | /** |
7dd3db54 | 226 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 227 | * @task: target task |
7dd3db54 | 228 | * @mask: pending bits to set |
d79fdd6d | 229 | * |
7dd3db54 TH |
230 | * Clear @mask from @task->jobctl. @mask must be subset of |
231 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
232 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
233 | * cleared. If @task is already being killed or exiting, this function | |
234 | * becomes noop. | |
235 | * | |
236 | * CONTEXT: | |
237 | * Must be called with @task->sighand->siglock held. | |
238 | * | |
239 | * RETURNS: | |
240 | * %true if @mask is set, %false if made noop because @task was dying. | |
241 | */ | |
242 | bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask) | |
243 | { | |
244 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
245 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
246 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
247 | ||
248 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
249 | return false; | |
250 | ||
251 | if (mask & JOBCTL_STOP_SIGMASK) | |
252 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
253 | ||
254 | task->jobctl |= mask; | |
255 | return true; | |
256 | } | |
257 | ||
d79fdd6d | 258 | /** |
a8f072c1 | 259 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
260 | * @task: target task |
261 | * | |
a8f072c1 TH |
262 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
263 | * Clear it and wake up the ptracer. Note that we don't need any further | |
264 | * locking. @task->siglock guarantees that @task->parent points to the | |
265 | * ptracer. | |
d79fdd6d TH |
266 | * |
267 | * CONTEXT: | |
268 | * Must be called with @task->sighand->siglock held. | |
269 | */ | |
73ddff2b | 270 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 271 | { |
a8f072c1 TH |
272 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
273 | task->jobctl &= ~JOBCTL_TRAPPING; | |
62c124ff | 274 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
275 | } |
276 | } | |
277 | ||
e5c1902e | 278 | /** |
3759a0d9 | 279 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 280 | * @task: target task |
3759a0d9 | 281 | * @mask: pending bits to clear |
e5c1902e | 282 | * |
3759a0d9 TH |
283 | * Clear @mask from @task->jobctl. @mask must be subset of |
284 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
285 | * STOP bits are cleared together. | |
e5c1902e | 286 | * |
6dfca329 TH |
287 | * If clearing of @mask leaves no stop or trap pending, this function calls |
288 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
289 | * |
290 | * CONTEXT: | |
291 | * Must be called with @task->sighand->siglock held. | |
292 | */ | |
3759a0d9 | 293 | void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask) |
e5c1902e | 294 | { |
3759a0d9 TH |
295 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
296 | ||
297 | if (mask & JOBCTL_STOP_PENDING) | |
298 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
299 | ||
300 | task->jobctl &= ~mask; | |
6dfca329 TH |
301 | |
302 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
303 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
304 | } |
305 | ||
306 | /** | |
307 | * task_participate_group_stop - participate in a group stop | |
308 | * @task: task participating in a group stop | |
309 | * | |
a8f072c1 | 310 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 311 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 312 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 313 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
314 | * |
315 | * CONTEXT: | |
316 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
317 | * |
318 | * RETURNS: | |
319 | * %true if group stop completion should be notified to the parent, %false | |
320 | * otherwise. | |
e5c1902e TH |
321 | */ |
322 | static bool task_participate_group_stop(struct task_struct *task) | |
323 | { | |
324 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 325 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 326 | |
a8f072c1 | 327 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 328 | |
3759a0d9 | 329 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
330 | |
331 | if (!consume) | |
332 | return false; | |
333 | ||
334 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
335 | sig->group_stop_count--; | |
336 | ||
244056f9 TH |
337 | /* |
338 | * Tell the caller to notify completion iff we are entering into a | |
339 | * fresh group stop. Read comment in do_signal_stop() for details. | |
340 | */ | |
341 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
e5c1902e TH |
342 | sig->flags = SIGNAL_STOP_STOPPED; |
343 | return true; | |
344 | } | |
345 | return false; | |
346 | } | |
347 | ||
c69e8d9c DH |
348 | /* |
349 | * allocate a new signal queue record | |
350 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 351 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 352 | */ |
f84d49b2 NO |
353 | static struct sigqueue * |
354 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
355 | { |
356 | struct sigqueue *q = NULL; | |
10b1fbdb | 357 | struct user_struct *user; |
1da177e4 | 358 | |
10b1fbdb | 359 | /* |
7cf7db8d TG |
360 | * Protect access to @t credentials. This can go away when all |
361 | * callers hold rcu read lock. | |
10b1fbdb | 362 | */ |
7cf7db8d | 363 | rcu_read_lock(); |
d84f4f99 | 364 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 365 | atomic_inc(&user->sigpending); |
7cf7db8d | 366 | rcu_read_unlock(); |
f84d49b2 | 367 | |
1da177e4 | 368 | if (override_rlimit || |
10b1fbdb | 369 | atomic_read(&user->sigpending) <= |
78d7d407 | 370 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 371 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
372 | } else { |
373 | print_dropped_signal(sig); | |
374 | } | |
375 | ||
1da177e4 | 376 | if (unlikely(q == NULL)) { |
10b1fbdb | 377 | atomic_dec(&user->sigpending); |
d84f4f99 | 378 | free_uid(user); |
1da177e4 LT |
379 | } else { |
380 | INIT_LIST_HEAD(&q->list); | |
381 | q->flags = 0; | |
d84f4f99 | 382 | q->user = user; |
1da177e4 | 383 | } |
d84f4f99 DH |
384 | |
385 | return q; | |
1da177e4 LT |
386 | } |
387 | ||
514a01b8 | 388 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
389 | { |
390 | if (q->flags & SIGQUEUE_PREALLOC) | |
391 | return; | |
392 | atomic_dec(&q->user->sigpending); | |
393 | free_uid(q->user); | |
394 | kmem_cache_free(sigqueue_cachep, q); | |
395 | } | |
396 | ||
6a14c5c9 | 397 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
398 | { |
399 | struct sigqueue *q; | |
400 | ||
401 | sigemptyset(&queue->signal); | |
402 | while (!list_empty(&queue->list)) { | |
403 | q = list_entry(queue->list.next, struct sigqueue , list); | |
404 | list_del_init(&q->list); | |
405 | __sigqueue_free(q); | |
406 | } | |
407 | } | |
408 | ||
409 | /* | |
410 | * Flush all pending signals for a task. | |
411 | */ | |
3bcac026 DH |
412 | void __flush_signals(struct task_struct *t) |
413 | { | |
414 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
415 | flush_sigqueue(&t->pending); | |
416 | flush_sigqueue(&t->signal->shared_pending); | |
417 | } | |
418 | ||
c81addc9 | 419 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
420 | { |
421 | unsigned long flags; | |
422 | ||
423 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
3bcac026 | 424 | __flush_signals(t); |
1da177e4 LT |
425 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
426 | } | |
427 | ||
cbaffba1 ON |
428 | static void __flush_itimer_signals(struct sigpending *pending) |
429 | { | |
430 | sigset_t signal, retain; | |
431 | struct sigqueue *q, *n; | |
432 | ||
433 | signal = pending->signal; | |
434 | sigemptyset(&retain); | |
435 | ||
436 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
437 | int sig = q->info.si_signo; | |
438 | ||
439 | if (likely(q->info.si_code != SI_TIMER)) { | |
440 | sigaddset(&retain, sig); | |
441 | } else { | |
442 | sigdelset(&signal, sig); | |
443 | list_del_init(&q->list); | |
444 | __sigqueue_free(q); | |
445 | } | |
446 | } | |
447 | ||
448 | sigorsets(&pending->signal, &signal, &retain); | |
449 | } | |
450 | ||
451 | void flush_itimer_signals(void) | |
452 | { | |
453 | struct task_struct *tsk = current; | |
454 | unsigned long flags; | |
455 | ||
456 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
457 | __flush_itimer_signals(&tsk->pending); | |
458 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
459 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
460 | } | |
461 | ||
10ab825b ON |
462 | void ignore_signals(struct task_struct *t) |
463 | { | |
464 | int i; | |
465 | ||
466 | for (i = 0; i < _NSIG; ++i) | |
467 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
468 | ||
469 | flush_signals(t); | |
470 | } | |
471 | ||
1da177e4 LT |
472 | /* |
473 | * Flush all handlers for a task. | |
474 | */ | |
475 | ||
476 | void | |
477 | flush_signal_handlers(struct task_struct *t, int force_default) | |
478 | { | |
479 | int i; | |
480 | struct k_sigaction *ka = &t->sighand->action[0]; | |
481 | for (i = _NSIG ; i != 0 ; i--) { | |
482 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
483 | ka->sa.sa_handler = SIG_DFL; | |
484 | ka->sa.sa_flags = 0; | |
485 | sigemptyset(&ka->sa.sa_mask); | |
486 | ka++; | |
487 | } | |
488 | } | |
489 | ||
abd4f750 MAS |
490 | int unhandled_signal(struct task_struct *tsk, int sig) |
491 | { | |
445a91d2 | 492 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 493 | if (is_global_init(tsk)) |
abd4f750 | 494 | return 1; |
445a91d2 | 495 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 496 | return 0; |
a288eecc TH |
497 | /* if ptraced, let the tracer determine */ |
498 | return !tsk->ptrace; | |
abd4f750 MAS |
499 | } |
500 | ||
5aba085e RD |
501 | /* |
502 | * Notify the system that a driver wants to block all signals for this | |
1da177e4 LT |
503 | * process, and wants to be notified if any signals at all were to be |
504 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
505 | * signal will be acted upon after all. If the notifier routine returns 0, | |
506 | * then then signal will be blocked. Only one block per process is | |
507 | * allowed. priv is a pointer to private data that the notifier routine | |
5aba085e RD |
508 | * can use to determine if the signal should be blocked or not. |
509 | */ | |
1da177e4 LT |
510 | void |
511 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
512 | { | |
513 | unsigned long flags; | |
514 | ||
515 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
516 | current->notifier_mask = mask; | |
517 | current->notifier_data = priv; | |
518 | current->notifier = notifier; | |
519 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
520 | } | |
521 | ||
522 | /* Notify the system that blocking has ended. */ | |
523 | ||
524 | void | |
525 | unblock_all_signals(void) | |
526 | { | |
527 | unsigned long flags; | |
528 | ||
529 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
530 | current->notifier = NULL; | |
531 | current->notifier_data = NULL; | |
532 | recalc_sigpending(); | |
533 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
534 | } | |
535 | ||
100360f0 | 536 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
537 | { |
538 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 539 | |
1da177e4 LT |
540 | /* |
541 | * Collect the siginfo appropriate to this signal. Check if | |
542 | * there is another siginfo for the same signal. | |
543 | */ | |
544 | list_for_each_entry(q, &list->list, list) { | |
545 | if (q->info.si_signo == sig) { | |
d4434207 ON |
546 | if (first) |
547 | goto still_pending; | |
1da177e4 LT |
548 | first = q; |
549 | } | |
550 | } | |
d4434207 ON |
551 | |
552 | sigdelset(&list->signal, sig); | |
553 | ||
1da177e4 | 554 | if (first) { |
d4434207 | 555 | still_pending: |
1da177e4 LT |
556 | list_del_init(&first->list); |
557 | copy_siginfo(info, &first->info); | |
558 | __sigqueue_free(first); | |
1da177e4 | 559 | } else { |
5aba085e RD |
560 | /* |
561 | * Ok, it wasn't in the queue. This must be | |
562 | * a fast-pathed signal or we must have been | |
563 | * out of queue space. So zero out the info. | |
1da177e4 | 564 | */ |
1da177e4 LT |
565 | info->si_signo = sig; |
566 | info->si_errno = 0; | |
7486e5d9 | 567 | info->si_code = SI_USER; |
1da177e4 LT |
568 | info->si_pid = 0; |
569 | info->si_uid = 0; | |
570 | } | |
1da177e4 LT |
571 | } |
572 | ||
573 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
574 | siginfo_t *info) | |
575 | { | |
27d91e07 | 576 | int sig = next_signal(pending, mask); |
1da177e4 | 577 | |
1da177e4 LT |
578 | if (sig) { |
579 | if (current->notifier) { | |
580 | if (sigismember(current->notifier_mask, sig)) { | |
581 | if (!(current->notifier)(current->notifier_data)) { | |
582 | clear_thread_flag(TIF_SIGPENDING); | |
583 | return 0; | |
584 | } | |
585 | } | |
586 | } | |
587 | ||
100360f0 | 588 | collect_signal(sig, pending, info); |
1da177e4 | 589 | } |
1da177e4 LT |
590 | |
591 | return sig; | |
592 | } | |
593 | ||
594 | /* | |
5aba085e | 595 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
596 | * expected to free it. |
597 | * | |
598 | * All callers have to hold the siglock. | |
599 | */ | |
600 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
601 | { | |
c5363d03 | 602 | int signr; |
caec4e8d BH |
603 | |
604 | /* We only dequeue private signals from ourselves, we don't let | |
605 | * signalfd steal them | |
606 | */ | |
b8fceee1 | 607 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 608 | if (!signr) { |
1da177e4 LT |
609 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
610 | mask, info); | |
8bfd9a7a TG |
611 | /* |
612 | * itimer signal ? | |
613 | * | |
614 | * itimers are process shared and we restart periodic | |
615 | * itimers in the signal delivery path to prevent DoS | |
616 | * attacks in the high resolution timer case. This is | |
5aba085e | 617 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
618 | * itimers, as the SIGALRM is a legacy signal and only |
619 | * queued once. Changing the restart behaviour to | |
620 | * restart the timer in the signal dequeue path is | |
621 | * reducing the timer noise on heavy loaded !highres | |
622 | * systems too. | |
623 | */ | |
624 | if (unlikely(signr == SIGALRM)) { | |
625 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
626 | ||
627 | if (!hrtimer_is_queued(tmr) && | |
628 | tsk->signal->it_real_incr.tv64 != 0) { | |
629 | hrtimer_forward(tmr, tmr->base->get_time(), | |
630 | tsk->signal->it_real_incr); | |
631 | hrtimer_restart(tmr); | |
632 | } | |
633 | } | |
634 | } | |
c5363d03 | 635 | |
b8fceee1 | 636 | recalc_sigpending(); |
c5363d03 PE |
637 | if (!signr) |
638 | return 0; | |
639 | ||
640 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
641 | /* |
642 | * Set a marker that we have dequeued a stop signal. Our | |
643 | * caller might release the siglock and then the pending | |
644 | * stop signal it is about to process is no longer in the | |
645 | * pending bitmasks, but must still be cleared by a SIGCONT | |
646 | * (and overruled by a SIGKILL). So those cases clear this | |
647 | * shared flag after we've set it. Note that this flag may | |
648 | * remain set after the signal we return is ignored or | |
649 | * handled. That doesn't matter because its only purpose | |
650 | * is to alert stop-signal processing code when another | |
651 | * processor has come along and cleared the flag. | |
652 | */ | |
a8f072c1 | 653 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 654 | } |
c5363d03 | 655 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
656 | /* |
657 | * Release the siglock to ensure proper locking order | |
658 | * of timer locks outside of siglocks. Note, we leave | |
659 | * irqs disabled here, since the posix-timers code is | |
660 | * about to disable them again anyway. | |
661 | */ | |
662 | spin_unlock(&tsk->sighand->siglock); | |
663 | do_schedule_next_timer(info); | |
664 | spin_lock(&tsk->sighand->siglock); | |
665 | } | |
666 | return signr; | |
667 | } | |
668 | ||
669 | /* | |
670 | * Tell a process that it has a new active signal.. | |
671 | * | |
672 | * NOTE! we rely on the previous spin_lock to | |
673 | * lock interrupts for us! We can only be called with | |
674 | * "siglock" held, and the local interrupt must | |
675 | * have been disabled when that got acquired! | |
676 | * | |
677 | * No need to set need_resched since signal event passing | |
678 | * goes through ->blocked | |
679 | */ | |
680 | void signal_wake_up(struct task_struct *t, int resume) | |
681 | { | |
682 | unsigned int mask; | |
683 | ||
684 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
685 | ||
686 | /* | |
f021a3c2 MW |
687 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
688 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
689 | * executing another processor and just now entering stopped state. |
690 | * By using wake_up_state, we ensure the process will wake up and | |
691 | * handle its death signal. | |
692 | */ | |
693 | mask = TASK_INTERRUPTIBLE; | |
694 | if (resume) | |
f021a3c2 | 695 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
696 | if (!wake_up_state(t, mask)) |
697 | kick_process(t); | |
698 | } | |
699 | ||
71fabd5e GA |
700 | /* |
701 | * Remove signals in mask from the pending set and queue. | |
702 | * Returns 1 if any signals were found. | |
703 | * | |
704 | * All callers must be holding the siglock. | |
705 | * | |
706 | * This version takes a sigset mask and looks at all signals, | |
707 | * not just those in the first mask word. | |
708 | */ | |
709 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
710 | { | |
711 | struct sigqueue *q, *n; | |
712 | sigset_t m; | |
713 | ||
714 | sigandsets(&m, mask, &s->signal); | |
715 | if (sigisemptyset(&m)) | |
716 | return 0; | |
717 | ||
702a5073 | 718 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
719 | list_for_each_entry_safe(q, n, &s->list, list) { |
720 | if (sigismember(mask, q->info.si_signo)) { | |
721 | list_del_init(&q->list); | |
722 | __sigqueue_free(q); | |
723 | } | |
724 | } | |
725 | return 1; | |
726 | } | |
1da177e4 LT |
727 | /* |
728 | * Remove signals in mask from the pending set and queue. | |
729 | * Returns 1 if any signals were found. | |
730 | * | |
731 | * All callers must be holding the siglock. | |
732 | */ | |
733 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
734 | { | |
735 | struct sigqueue *q, *n; | |
736 | ||
737 | if (!sigtestsetmask(&s->signal, mask)) | |
738 | return 0; | |
739 | ||
740 | sigdelsetmask(&s->signal, mask); | |
741 | list_for_each_entry_safe(q, n, &s->list, list) { | |
742 | if (q->info.si_signo < SIGRTMIN && | |
743 | (mask & sigmask(q->info.si_signo))) { | |
744 | list_del_init(&q->list); | |
745 | __sigqueue_free(q); | |
746 | } | |
747 | } | |
748 | return 1; | |
749 | } | |
750 | ||
614c517d ON |
751 | static inline int is_si_special(const struct siginfo *info) |
752 | { | |
753 | return info <= SEND_SIG_FORCED; | |
754 | } | |
755 | ||
756 | static inline bool si_fromuser(const struct siginfo *info) | |
757 | { | |
758 | return info == SEND_SIG_NOINFO || | |
759 | (!is_si_special(info) && SI_FROMUSER(info)); | |
760 | } | |
761 | ||
39fd3393 SH |
762 | /* |
763 | * called with RCU read lock from check_kill_permission() | |
764 | */ | |
765 | static int kill_ok_by_cred(struct task_struct *t) | |
766 | { | |
767 | const struct cred *cred = current_cred(); | |
768 | const struct cred *tcred = __task_cred(t); | |
769 | ||
c4a4d603 | 770 | if (cred->user_ns == tcred->user_ns && |
39fd3393 SH |
771 | (cred->euid == tcred->suid || |
772 | cred->euid == tcred->uid || | |
773 | cred->uid == tcred->suid || | |
774 | cred->uid == tcred->uid)) | |
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); | |
544b2c91 | 845 | 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 | /* |
1024 | * map the uid in struct cred into user namespace *ns | |
1025 | */ | |
1026 | static inline uid_t map_cred_ns(const struct cred *cred, | |
1027 | struct user_namespace *ns) | |
1028 | { | |
76b6db01 | 1029 | return from_kuid_munged(ns, cred->uid); |
6b550f94 SH |
1030 | } |
1031 | ||
1032 | #ifdef CONFIG_USER_NS | |
1033 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1034 | { | |
1035 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
1036 | return; | |
1037 | ||
1038 | if (SI_FROMKERNEL(info)) | |
1039 | return; | |
1040 | ||
078de5f7 EB |
1041 | rcu_read_lock(); |
1042 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
1043 | make_kuid(current_user_ns(), info->si_uid)); | |
1044 | rcu_read_unlock(); | |
6b550f94 SH |
1045 | } |
1046 | #else | |
1047 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1048 | { | |
1049 | return; | |
1050 | } | |
1051 | #endif | |
1052 | ||
7978b567 SB |
1053 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1054 | int group, int from_ancestor_ns) | |
1da177e4 | 1055 | { |
2ca3515a | 1056 | struct sigpending *pending; |
6e65acba | 1057 | struct sigqueue *q; |
7a0aeb14 | 1058 | int override_rlimit; |
6c303d3a | 1059 | int ret = 0, result; |
0a16b607 | 1060 | |
6e65acba | 1061 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1062 | |
6c303d3a | 1063 | result = TRACE_SIGNAL_IGNORED; |
629d362b ON |
1064 | if (!prepare_signal(sig, t, |
1065 | from_ancestor_ns || (info == SEND_SIG_FORCED))) | |
6c303d3a | 1066 | goto ret; |
2ca3515a ON |
1067 | |
1068 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
1069 | /* |
1070 | * Short-circuit ignored signals and support queuing | |
1071 | * exactly one non-rt signal, so that we can get more | |
1072 | * detailed information about the cause of the signal. | |
1073 | */ | |
6c303d3a | 1074 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1075 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1076 | goto ret; |
1077 | ||
1078 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1079 | /* |
1080 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1081 | * or SIGKILL. | |
1082 | */ | |
b67a1b9e | 1083 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1084 | goto out_set; |
1085 | ||
5aba085e RD |
1086 | /* |
1087 | * Real-time signals must be queued if sent by sigqueue, or | |
1088 | * some other real-time mechanism. It is implementation | |
1089 | * defined whether kill() does so. We attempt to do so, on | |
1090 | * the principle of least surprise, but since kill is not | |
1091 | * allowed to fail with EAGAIN when low on memory we just | |
1092 | * make sure at least one signal gets delivered and don't | |
1093 | * pass on the info struct. | |
1094 | */ | |
7a0aeb14 VN |
1095 | if (sig < SIGRTMIN) |
1096 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1097 | else | |
1098 | override_rlimit = 0; | |
1099 | ||
f84d49b2 | 1100 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1101 | override_rlimit); |
1da177e4 | 1102 | if (q) { |
2ca3515a | 1103 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1104 | switch ((unsigned long) info) { |
b67a1b9e | 1105 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1106 | q->info.si_signo = sig; |
1107 | q->info.si_errno = 0; | |
1108 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1109 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1110 | task_active_pid_ns(t)); |
078de5f7 | 1111 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1112 | break; |
b67a1b9e | 1113 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1114 | q->info.si_signo = sig; |
1115 | q->info.si_errno = 0; | |
1116 | q->info.si_code = SI_KERNEL; | |
1117 | q->info.si_pid = 0; | |
1118 | q->info.si_uid = 0; | |
1119 | break; | |
1120 | default: | |
1121 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1122 | if (from_ancestor_ns) |
1123 | q->info.si_pid = 0; | |
1da177e4 LT |
1124 | break; |
1125 | } | |
6b550f94 SH |
1126 | |
1127 | userns_fixup_signal_uid(&q->info, t); | |
1128 | ||
621d3121 | 1129 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1130 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1131 | /* | |
1132 | * Queue overflow, abort. We may abort if the | |
1133 | * signal was rt and sent by user using something | |
1134 | * other than kill(). | |
1135 | */ | |
6c303d3a ON |
1136 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1137 | ret = -EAGAIN; | |
1138 | goto ret; | |
ba005e1f MH |
1139 | } else { |
1140 | /* | |
1141 | * This is a silent loss of information. We still | |
1142 | * send the signal, but the *info bits are lost. | |
1143 | */ | |
6c303d3a | 1144 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1145 | } |
1da177e4 LT |
1146 | } |
1147 | ||
1148 | out_set: | |
53c30337 | 1149 | signalfd_notify(t, sig); |
2ca3515a | 1150 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1151 | complete_signal(sig, t, group); |
6c303d3a ON |
1152 | ret: |
1153 | trace_signal_generate(sig, info, t, group, result); | |
1154 | return ret; | |
1da177e4 LT |
1155 | } |
1156 | ||
7978b567 SB |
1157 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1158 | int group) | |
1159 | { | |
921cf9f6 SB |
1160 | int from_ancestor_ns = 0; |
1161 | ||
1162 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1163 | from_ancestor_ns = si_fromuser(info) && |
1164 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1165 | #endif |
1166 | ||
1167 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1168 | } |
1169 | ||
45807a1d IM |
1170 | static void print_fatal_signal(struct pt_regs *regs, int signr) |
1171 | { | |
1172 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 1173 | current->comm, task_pid_nr(current), signr); |
45807a1d | 1174 | |
ca5cd877 | 1175 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 1176 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
1177 | { |
1178 | int i; | |
1179 | for (i = 0; i < 16; i++) { | |
1180 | unsigned char insn; | |
1181 | ||
b45c6e76 AK |
1182 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1183 | break; | |
45807a1d IM |
1184 | printk("%02x ", insn); |
1185 | } | |
1186 | } | |
1187 | #endif | |
1188 | printk("\n"); | |
3a9f84d3 | 1189 | preempt_disable(); |
45807a1d | 1190 | show_regs(regs); |
3a9f84d3 | 1191 | preempt_enable(); |
45807a1d IM |
1192 | } |
1193 | ||
1194 | static int __init setup_print_fatal_signals(char *str) | |
1195 | { | |
1196 | get_option (&str, &print_fatal_signals); | |
1197 | ||
1198 | return 1; | |
1199 | } | |
1200 | ||
1201 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1202 | |
4cd4b6d4 PE |
1203 | int |
1204 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1205 | { | |
1206 | return send_signal(sig, info, p, 1); | |
1207 | } | |
1208 | ||
1da177e4 LT |
1209 | static int |
1210 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1211 | { | |
4cd4b6d4 | 1212 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1213 | } |
1214 | ||
4a30debf ON |
1215 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1216 | bool group) | |
1217 | { | |
1218 | unsigned long flags; | |
1219 | int ret = -ESRCH; | |
1220 | ||
1221 | if (lock_task_sighand(p, &flags)) { | |
1222 | ret = send_signal(sig, info, p, group); | |
1223 | unlock_task_sighand(p, &flags); | |
1224 | } | |
1225 | ||
1226 | return ret; | |
1227 | } | |
1228 | ||
1da177e4 LT |
1229 | /* |
1230 | * Force a signal that the process can't ignore: if necessary | |
1231 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1232 | * |
1233 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1234 | * since we do not want to have a signal handler that was blocked | |
1235 | * be invoked when user space had explicitly blocked it. | |
1236 | * | |
80fe728d ON |
1237 | * We don't want to have recursive SIGSEGV's etc, for example, |
1238 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1239 | */ |
1da177e4 LT |
1240 | int |
1241 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1242 | { | |
1243 | unsigned long int flags; | |
ae74c3b6 LT |
1244 | int ret, blocked, ignored; |
1245 | struct k_sigaction *action; | |
1da177e4 LT |
1246 | |
1247 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1248 | action = &t->sighand->action[sig-1]; |
1249 | ignored = action->sa.sa_handler == SIG_IGN; | |
1250 | blocked = sigismember(&t->blocked, sig); | |
1251 | if (blocked || ignored) { | |
1252 | action->sa.sa_handler = SIG_DFL; | |
1253 | if (blocked) { | |
1254 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1255 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1256 | } |
1da177e4 | 1257 | } |
80fe728d ON |
1258 | if (action->sa.sa_handler == SIG_DFL) |
1259 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1260 | ret = specific_send_sig_info(sig, info, t); |
1261 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1262 | ||
1263 | return ret; | |
1264 | } | |
1265 | ||
1da177e4 LT |
1266 | /* |
1267 | * Nuke all other threads in the group. | |
1268 | */ | |
09faef11 | 1269 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1270 | { |
09faef11 ON |
1271 | struct task_struct *t = p; |
1272 | int count = 0; | |
1da177e4 | 1273 | |
1da177e4 LT |
1274 | p->signal->group_stop_count = 0; |
1275 | ||
09faef11 | 1276 | while_each_thread(p, t) { |
6dfca329 | 1277 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1278 | count++; |
1279 | ||
1280 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1281 | if (t->exit_state) |
1282 | continue; | |
1da177e4 | 1283 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1284 | signal_wake_up(t, 1); |
1285 | } | |
09faef11 ON |
1286 | |
1287 | return count; | |
1da177e4 LT |
1288 | } |
1289 | ||
b8ed374e NK |
1290 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1291 | unsigned long *flags) | |
f63ee72e ON |
1292 | { |
1293 | struct sighand_struct *sighand; | |
1294 | ||
1295 | for (;;) { | |
a841796f PM |
1296 | local_irq_save(*flags); |
1297 | rcu_read_lock(); | |
f63ee72e | 1298 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1299 | if (unlikely(sighand == NULL)) { |
1300 | rcu_read_unlock(); | |
1301 | local_irq_restore(*flags); | |
f63ee72e | 1302 | break; |
a841796f | 1303 | } |
f63ee72e | 1304 | |
a841796f PM |
1305 | spin_lock(&sighand->siglock); |
1306 | if (likely(sighand == tsk->sighand)) { | |
1307 | rcu_read_unlock(); | |
f63ee72e | 1308 | break; |
a841796f PM |
1309 | } |
1310 | spin_unlock(&sighand->siglock); | |
1311 | rcu_read_unlock(); | |
1312 | local_irq_restore(*flags); | |
f63ee72e ON |
1313 | } |
1314 | ||
1315 | return sighand; | |
1316 | } | |
1317 | ||
c69e8d9c DH |
1318 | /* |
1319 | * send signal info to all the members of a group | |
c69e8d9c | 1320 | */ |
1da177e4 LT |
1321 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1322 | { | |
694f690d DH |
1323 | int ret; |
1324 | ||
1325 | rcu_read_lock(); | |
1326 | ret = check_kill_permission(sig, info, p); | |
1327 | rcu_read_unlock(); | |
f63ee72e | 1328 | |
4a30debf ON |
1329 | if (!ret && sig) |
1330 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1331 | |
1332 | return ret; | |
1333 | } | |
1334 | ||
1335 | /* | |
146a505d | 1336 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1337 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1338 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1339 | */ |
c4b92fc1 | 1340 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1341 | { |
1342 | struct task_struct *p = NULL; | |
1343 | int retval, success; | |
1344 | ||
1da177e4 LT |
1345 | success = 0; |
1346 | retval = -ESRCH; | |
c4b92fc1 | 1347 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1348 | int err = group_send_sig_info(sig, info, p); |
1349 | success |= !err; | |
1350 | retval = err; | |
c4b92fc1 | 1351 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1352 | return success ? 0 : retval; |
1353 | } | |
1354 | ||
c4b92fc1 | 1355 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1356 | { |
d36174bc | 1357 | int error = -ESRCH; |
1da177e4 LT |
1358 | struct task_struct *p; |
1359 | ||
e56d0903 | 1360 | rcu_read_lock(); |
d36174bc | 1361 | retry: |
c4b92fc1 | 1362 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1363 | if (p) { |
1da177e4 | 1364 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1365 | if (unlikely(error == -ESRCH)) |
1366 | /* | |
1367 | * The task was unhashed in between, try again. | |
1368 | * If it is dead, pid_task() will return NULL, | |
1369 | * if we race with de_thread() it will find the | |
1370 | * new leader. | |
1371 | */ | |
1372 | goto retry; | |
1373 | } | |
e56d0903 | 1374 | rcu_read_unlock(); |
6ca25b55 | 1375 | |
1da177e4 LT |
1376 | return error; |
1377 | } | |
1378 | ||
5aba085e | 1379 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1380 | { |
1381 | int error; | |
1382 | rcu_read_lock(); | |
b488893a | 1383 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1384 | rcu_read_unlock(); |
1385 | return error; | |
1386 | } | |
1387 | ||
d178bc3a SH |
1388 | static int kill_as_cred_perm(const struct cred *cred, |
1389 | struct task_struct *target) | |
1390 | { | |
1391 | const struct cred *pcred = __task_cred(target); | |
1392 | if (cred->user_ns != pcred->user_ns) | |
1393 | return 0; | |
1394 | if (cred->euid != pcred->suid && cred->euid != pcred->uid && | |
1395 | cred->uid != pcred->suid && cred->uid != pcred->uid) | |
1396 | return 0; | |
1397 | return 1; | |
1398 | } | |
1399 | ||
2425c08b | 1400 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1401 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1402 | const struct cred *cred, u32 secid) | |
46113830 HW |
1403 | { |
1404 | int ret = -EINVAL; | |
1405 | struct task_struct *p; | |
14d8c9f3 | 1406 | unsigned long flags; |
46113830 HW |
1407 | |
1408 | if (!valid_signal(sig)) | |
1409 | return ret; | |
1410 | ||
14d8c9f3 | 1411 | rcu_read_lock(); |
2425c08b | 1412 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1413 | if (!p) { |
1414 | ret = -ESRCH; | |
1415 | goto out_unlock; | |
1416 | } | |
d178bc3a | 1417 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1418 | ret = -EPERM; |
1419 | goto out_unlock; | |
1420 | } | |
8f95dc58 DQ |
1421 | ret = security_task_kill(p, info, sig, secid); |
1422 | if (ret) | |
1423 | goto out_unlock; | |
14d8c9f3 TG |
1424 | |
1425 | if (sig) { | |
1426 | if (lock_task_sighand(p, &flags)) { | |
1427 | ret = __send_signal(sig, info, p, 1, 0); | |
1428 | unlock_task_sighand(p, &flags); | |
1429 | } else | |
1430 | ret = -ESRCH; | |
46113830 HW |
1431 | } |
1432 | out_unlock: | |
14d8c9f3 | 1433 | rcu_read_unlock(); |
46113830 HW |
1434 | return ret; |
1435 | } | |
d178bc3a | 1436 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1437 | |
1438 | /* | |
1439 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1440 | * | |
1441 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1442 | * is probably wrong. Should make it like BSD or SYSV. | |
1443 | */ | |
1444 | ||
bc64efd2 | 1445 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1446 | { |
8d42db18 | 1447 | int ret; |
d5df763b PE |
1448 | |
1449 | if (pid > 0) { | |
1450 | rcu_read_lock(); | |
1451 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1452 | rcu_read_unlock(); | |
1453 | return ret; | |
1454 | } | |
1455 | ||
1456 | read_lock(&tasklist_lock); | |
1457 | if (pid != -1) { | |
1458 | ret = __kill_pgrp_info(sig, info, | |
1459 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1460 | } else { | |
1da177e4 LT |
1461 | int retval = 0, count = 0; |
1462 | struct task_struct * p; | |
1463 | ||
1da177e4 | 1464 | for_each_process(p) { |
d25141a8 SB |
1465 | if (task_pid_vnr(p) > 1 && |
1466 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1467 | int err = group_send_sig_info(sig, info, p); |
1468 | ++count; | |
1469 | if (err != -EPERM) | |
1470 | retval = err; | |
1471 | } | |
1472 | } | |
8d42db18 | 1473 | ret = count ? retval : -ESRCH; |
1da177e4 | 1474 | } |
d5df763b PE |
1475 | read_unlock(&tasklist_lock); |
1476 | ||
8d42db18 | 1477 | return ret; |
1da177e4 LT |
1478 | } |
1479 | ||
1480 | /* | |
1481 | * These are for backward compatibility with the rest of the kernel source. | |
1482 | */ | |
1483 | ||
5aba085e | 1484 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1485 | { |
1da177e4 LT |
1486 | /* |
1487 | * Make sure legacy kernel users don't send in bad values | |
1488 | * (normal paths check this in check_kill_permission). | |
1489 | */ | |
7ed20e1a | 1490 | if (!valid_signal(sig)) |
1da177e4 LT |
1491 | return -EINVAL; |
1492 | ||
4a30debf | 1493 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1494 | } |
1495 | ||
b67a1b9e ON |
1496 | #define __si_special(priv) \ |
1497 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1498 | ||
1da177e4 LT |
1499 | int |
1500 | send_sig(int sig, struct task_struct *p, int priv) | |
1501 | { | |
b67a1b9e | 1502 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1503 | } |
1504 | ||
1da177e4 LT |
1505 | void |
1506 | force_sig(int sig, struct task_struct *p) | |
1507 | { | |
b67a1b9e | 1508 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1509 | } |
1510 | ||
1511 | /* | |
1512 | * When things go south during signal handling, we | |
1513 | * will force a SIGSEGV. And if the signal that caused | |
1514 | * the problem was already a SIGSEGV, we'll want to | |
1515 | * make sure we don't even try to deliver the signal.. | |
1516 | */ | |
1517 | int | |
1518 | force_sigsegv(int sig, struct task_struct *p) | |
1519 | { | |
1520 | if (sig == SIGSEGV) { | |
1521 | unsigned long flags; | |
1522 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1523 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1524 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1525 | } | |
1526 | force_sig(SIGSEGV, p); | |
1527 | return 0; | |
1528 | } | |
1529 | ||
c4b92fc1 EB |
1530 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1531 | { | |
146a505d PE |
1532 | int ret; |
1533 | ||
1534 | read_lock(&tasklist_lock); | |
1535 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1536 | read_unlock(&tasklist_lock); | |
1537 | ||
1538 | return ret; | |
c4b92fc1 EB |
1539 | } |
1540 | EXPORT_SYMBOL(kill_pgrp); | |
1541 | ||
1542 | int kill_pid(struct pid *pid, int sig, int priv) | |
1543 | { | |
1544 | return kill_pid_info(sig, __si_special(priv), pid); | |
1545 | } | |
1546 | EXPORT_SYMBOL(kill_pid); | |
1547 | ||
1da177e4 LT |
1548 | /* |
1549 | * These functions support sending signals using preallocated sigqueue | |
1550 | * structures. This is needed "because realtime applications cannot | |
1551 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1552 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1553 | * we allocate the sigqueue structure from the timer_create. If this |
1554 | * allocation fails we are able to report the failure to the application | |
1555 | * with an EAGAIN error. | |
1556 | */ | |
1da177e4 LT |
1557 | struct sigqueue *sigqueue_alloc(void) |
1558 | { | |
f84d49b2 | 1559 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1560 | |
f84d49b2 | 1561 | if (q) |
1da177e4 | 1562 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1563 | |
1564 | return q; | |
1da177e4 LT |
1565 | } |
1566 | ||
1567 | void sigqueue_free(struct sigqueue *q) | |
1568 | { | |
1569 | unsigned long flags; | |
60187d27 ON |
1570 | spinlock_t *lock = ¤t->sighand->siglock; |
1571 | ||
1da177e4 LT |
1572 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1573 | /* | |
c8e85b4f ON |
1574 | * We must hold ->siglock while testing q->list |
1575 | * to serialize with collect_signal() or with | |
da7978b0 | 1576 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1577 | */ |
60187d27 | 1578 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1579 | q->flags &= ~SIGQUEUE_PREALLOC; |
1580 | /* | |
1581 | * If it is queued it will be freed when dequeued, | |
1582 | * like the "regular" sigqueue. | |
1583 | */ | |
60187d27 | 1584 | if (!list_empty(&q->list)) |
c8e85b4f | 1585 | q = NULL; |
60187d27 ON |
1586 | spin_unlock_irqrestore(lock, flags); |
1587 | ||
c8e85b4f ON |
1588 | if (q) |
1589 | __sigqueue_free(q); | |
1da177e4 LT |
1590 | } |
1591 | ||
ac5c2153 | 1592 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1593 | { |
e62e6650 | 1594 | int sig = q->info.si_signo; |
2ca3515a | 1595 | struct sigpending *pending; |
e62e6650 | 1596 | unsigned long flags; |
163566f6 | 1597 | int ret, result; |
2ca3515a | 1598 | |
4cd4b6d4 | 1599 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1600 | |
1601 | ret = -1; | |
1602 | if (!likely(lock_task_sighand(t, &flags))) | |
1603 | goto ret; | |
1604 | ||
7e695a5e | 1605 | ret = 1; /* the signal is ignored */ |
163566f6 | 1606 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1607 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1608 | goto out; |
1609 | ||
1610 | ret = 0; | |
9e3bd6c3 PE |
1611 | if (unlikely(!list_empty(&q->list))) { |
1612 | /* | |
1613 | * If an SI_TIMER entry is already queue just increment | |
1614 | * the overrun count. | |
1615 | */ | |
9e3bd6c3 PE |
1616 | BUG_ON(q->info.si_code != SI_TIMER); |
1617 | q->info.si_overrun++; | |
163566f6 | 1618 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1619 | goto out; |
9e3bd6c3 | 1620 | } |
ba661292 | 1621 | q->info.si_overrun = 0; |
9e3bd6c3 | 1622 | |
9e3bd6c3 | 1623 | signalfd_notify(t, sig); |
2ca3515a | 1624 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1625 | list_add_tail(&q->list, &pending->list); |
1626 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1627 | complete_signal(sig, t, group); |
163566f6 | 1628 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1629 | out: |
163566f6 | 1630 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1631 | unlock_task_sighand(t, &flags); |
1632 | ret: | |
1633 | return ret; | |
9e3bd6c3 PE |
1634 | } |
1635 | ||
1da177e4 LT |
1636 | /* |
1637 | * Let a parent know about the death of a child. | |
1638 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1639 | * |
53c8f9f1 ON |
1640 | * Returns true if our parent ignored us and so we've switched to |
1641 | * self-reaping. | |
1da177e4 | 1642 | */ |
53c8f9f1 | 1643 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1644 | { |
1645 | struct siginfo info; | |
1646 | unsigned long flags; | |
1647 | struct sighand_struct *psig; | |
53c8f9f1 | 1648 | bool autoreap = false; |
1da177e4 LT |
1649 | |
1650 | BUG_ON(sig == -1); | |
1651 | ||
1652 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1653 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1654 | |
d21142ec | 1655 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1656 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1657 | ||
b6e238dc ON |
1658 | if (sig != SIGCHLD) { |
1659 | /* | |
1660 | * This is only possible if parent == real_parent. | |
1661 | * Check if it has changed security domain. | |
1662 | */ | |
1663 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1664 | sig = SIGCHLD; | |
1665 | } | |
1666 | ||
1da177e4 LT |
1667 | info.si_signo = sig; |
1668 | info.si_errno = 0; | |
b488893a PE |
1669 | /* |
1670 | * we are under tasklist_lock here so our parent is tied to | |
1671 | * us and cannot exit and release its namespace. | |
1672 | * | |
1673 | * the only it can is to switch its nsproxy with sys_unshare, | |
1674 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1675 | * see relevant namespace | |
1676 | * | |
1677 | * write_lock() currently calls preempt_disable() which is the | |
1678 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1679 | * correct to rely on this | |
1680 | */ | |
1681 | rcu_read_lock(); | |
1682 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
6b550f94 SH |
1683 | info.si_uid = map_cred_ns(__task_cred(tsk), |
1684 | task_cred_xxx(tsk->parent, user_ns)); | |
b488893a PE |
1685 | rcu_read_unlock(); |
1686 | ||
64861634 MS |
1687 | info.si_utime = cputime_to_clock_t(tsk->utime + tsk->signal->utime); |
1688 | info.si_stime = cputime_to_clock_t(tsk->stime + tsk->signal->stime); | |
1da177e4 LT |
1689 | |
1690 | info.si_status = tsk->exit_code & 0x7f; | |
1691 | if (tsk->exit_code & 0x80) | |
1692 | info.si_code = CLD_DUMPED; | |
1693 | else if (tsk->exit_code & 0x7f) | |
1694 | info.si_code = CLD_KILLED; | |
1695 | else { | |
1696 | info.si_code = CLD_EXITED; | |
1697 | info.si_status = tsk->exit_code >> 8; | |
1698 | } | |
1699 | ||
1700 | psig = tsk->parent->sighand; | |
1701 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1702 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1703 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1704 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1705 | /* | |
1706 | * We are exiting and our parent doesn't care. POSIX.1 | |
1707 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1708 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1709 | * automatically and not left for our parent's wait4 call. | |
1710 | * Rather than having the parent do it as a magic kind of | |
1711 | * signal handler, we just set this to tell do_exit that we | |
1712 | * can be cleaned up without becoming a zombie. Note that | |
1713 | * we still call __wake_up_parent in this case, because a | |
1714 | * blocked sys_wait4 might now return -ECHILD. | |
1715 | * | |
1716 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1717 | * is implementation-defined: we do (if you don't want | |
1718 | * it, just use SIG_IGN instead). | |
1719 | */ | |
53c8f9f1 | 1720 | autoreap = true; |
1da177e4 | 1721 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1722 | sig = 0; |
1da177e4 | 1723 | } |
53c8f9f1 | 1724 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1725 | __group_send_sig_info(sig, &info, tsk->parent); |
1726 | __wake_up_parent(tsk, tsk->parent); | |
1727 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1728 | |
53c8f9f1 | 1729 | return autoreap; |
1da177e4 LT |
1730 | } |
1731 | ||
75b95953 TH |
1732 | /** |
1733 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1734 | * @tsk: task reporting the state change | |
1735 | * @for_ptracer: the notification is for ptracer | |
1736 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1737 | * | |
1738 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1739 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1740 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1741 | * | |
1742 | * CONTEXT: | |
1743 | * Must be called with tasklist_lock at least read locked. | |
1744 | */ | |
1745 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1746 | bool for_ptracer, int why) | |
1da177e4 LT |
1747 | { |
1748 | struct siginfo info; | |
1749 | unsigned long flags; | |
bc505a47 | 1750 | struct task_struct *parent; |
1da177e4 LT |
1751 | struct sighand_struct *sighand; |
1752 | ||
75b95953 | 1753 | if (for_ptracer) { |
bc505a47 | 1754 | parent = tsk->parent; |
75b95953 | 1755 | } else { |
bc505a47 ON |
1756 | tsk = tsk->group_leader; |
1757 | parent = tsk->real_parent; | |
1758 | } | |
1759 | ||
1da177e4 LT |
1760 | info.si_signo = SIGCHLD; |
1761 | info.si_errno = 0; | |
b488893a | 1762 | /* |
5aba085e | 1763 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1764 | */ |
1765 | rcu_read_lock(); | |
d9265663 | 1766 | info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns); |
6b550f94 SH |
1767 | info.si_uid = map_cred_ns(__task_cred(tsk), |
1768 | task_cred_xxx(parent, user_ns)); | |
b488893a PE |
1769 | rcu_read_unlock(); |
1770 | ||
d8878ba3 MK |
1771 | info.si_utime = cputime_to_clock_t(tsk->utime); |
1772 | info.si_stime = cputime_to_clock_t(tsk->stime); | |
1da177e4 LT |
1773 | |
1774 | info.si_code = why; | |
1775 | switch (why) { | |
1776 | case CLD_CONTINUED: | |
1777 | info.si_status = SIGCONT; | |
1778 | break; | |
1779 | case CLD_STOPPED: | |
1780 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1781 | break; | |
1782 | case CLD_TRAPPED: | |
1783 | info.si_status = tsk->exit_code & 0x7f; | |
1784 | break; | |
1785 | default: | |
1786 | BUG(); | |
1787 | } | |
1788 | ||
1789 | sighand = parent->sighand; | |
1790 | spin_lock_irqsave(&sighand->siglock, flags); | |
1791 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1792 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1793 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1794 | /* | |
1795 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1796 | */ | |
1797 | __wake_up_parent(tsk, parent); | |
1798 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1799 | } | |
1800 | ||
d5f70c00 ON |
1801 | static inline int may_ptrace_stop(void) |
1802 | { | |
d21142ec | 1803 | if (!likely(current->ptrace)) |
d5f70c00 | 1804 | return 0; |
d5f70c00 ON |
1805 | /* |
1806 | * Are we in the middle of do_coredump? | |
1807 | * If so and our tracer is also part of the coredump stopping | |
1808 | * is a deadlock situation, and pointless because our tracer | |
1809 | * is dead so don't allow us to stop. | |
1810 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1811 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 ON |
1812 | * is safe to enter schedule(). |
1813 | */ | |
999d9fc1 | 1814 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1815 | unlikely(current->mm == current->parent->mm)) |
1816 | return 0; | |
1817 | ||
1818 | return 1; | |
1819 | } | |
1820 | ||
1a669c2f | 1821 | /* |
5aba085e | 1822 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1823 | * Called with the siglock held. |
1824 | */ | |
1825 | static int sigkill_pending(struct task_struct *tsk) | |
1826 | { | |
3d749b9e ON |
1827 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1828 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1829 | } |
1830 | ||
1da177e4 LT |
1831 | /* |
1832 | * This must be called with current->sighand->siglock held. | |
1833 | * | |
1834 | * This should be the path for all ptrace stops. | |
1835 | * We always set current->last_siginfo while stopped here. | |
1836 | * That makes it a way to test a stopped process for | |
1837 | * being ptrace-stopped vs being job-control-stopped. | |
1838 | * | |
20686a30 ON |
1839 | * If we actually decide not to stop at all because the tracer |
1840 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1841 | */ |
fe1bc6a0 | 1842 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1843 | __releases(¤t->sighand->siglock) |
1844 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1845 | { |
ceb6bd67 TH |
1846 | bool gstop_done = false; |
1847 | ||
1a669c2f RM |
1848 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1849 | /* | |
1850 | * The arch code has something special to do before a | |
1851 | * ptrace stop. This is allowed to block, e.g. for faults | |
1852 | * on user stack pages. We can't keep the siglock while | |
1853 | * calling arch_ptrace_stop, so we must release it now. | |
1854 | * To preserve proper semantics, we must do this before | |
1855 | * any signal bookkeeping like checking group_stop_count. | |
1856 | * Meanwhile, a SIGKILL could come in before we retake the | |
1857 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1858 | * So after regaining the lock, we must check for SIGKILL. | |
1859 | */ | |
1860 | spin_unlock_irq(¤t->sighand->siglock); | |
1861 | arch_ptrace_stop(exit_code, info); | |
1862 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1863 | if (sigkill_pending(current)) |
1864 | return; | |
1a669c2f RM |
1865 | } |
1866 | ||
1da177e4 | 1867 | /* |
81be24b8 TH |
1868 | * We're committing to trapping. TRACED should be visible before |
1869 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1870 | * Also, transition to TRACED and updates to ->jobctl should be | |
1871 | * atomic with respect to siglock and should be done after the arch | |
1872 | * hook as siglock is released and regrabbed across it. | |
1da177e4 | 1873 | */ |
81be24b8 | 1874 | set_current_state(TASK_TRACED); |
1da177e4 LT |
1875 | |
1876 | current->last_siginfo = info; | |
1877 | current->exit_code = exit_code; | |
1878 | ||
d79fdd6d | 1879 | /* |
0ae8ce1c TH |
1880 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1881 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1882 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1883 | * could be clear now. We act as if SIGCONT is received after | |
1884 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1885 | */ |
a8f072c1 | 1886 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1887 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1888 | |
fb1d910c | 1889 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1890 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1891 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1892 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1893 | |
81be24b8 | 1894 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1895 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1896 | |
1da177e4 LT |
1897 | spin_unlock_irq(¤t->sighand->siglock); |
1898 | read_lock(&tasklist_lock); | |
3d749b9e | 1899 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1900 | /* |
1901 | * Notify parents of the stop. | |
1902 | * | |
1903 | * While ptraced, there are two parents - the ptracer and | |
1904 | * the real_parent of the group_leader. The ptracer should | |
1905 | * know about every stop while the real parent is only | |
1906 | * interested in the completion of group stop. The states | |
1907 | * for the two don't interact with each other. Notify | |
1908 | * separately unless they're gonna be duplicates. | |
1909 | */ | |
1910 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1911 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1912 | do_notify_parent_cldstop(current, false, why); |
1913 | ||
53da1d94 MS |
1914 | /* |
1915 | * Don't want to allow preemption here, because | |
1916 | * sys_ptrace() needs this task to be inactive. | |
1917 | * | |
1918 | * XXX: implement read_unlock_no_resched(). | |
1919 | */ | |
1920 | preempt_disable(); | |
1da177e4 | 1921 | read_unlock(&tasklist_lock); |
53da1d94 | 1922 | preempt_enable_no_resched(); |
1da177e4 LT |
1923 | schedule(); |
1924 | } else { | |
1925 | /* | |
1926 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1927 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1928 | * |
1929 | * If @gstop_done, the ptracer went away between group stop | |
1930 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1931 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1932 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1933 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1934 | */ |
ceb6bd67 TH |
1935 | if (gstop_done) |
1936 | do_notify_parent_cldstop(current, false, why); | |
1937 | ||
6405f7f4 | 1938 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1939 | if (clear_code) |
1940 | current->exit_code = 0; | |
6405f7f4 | 1941 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1942 | } |
1943 | ||
13b1c3d4 RM |
1944 | /* |
1945 | * While in TASK_TRACED, we were considered "frozen enough". | |
1946 | * Now that we woke up, it's crucial if we're supposed to be | |
1947 | * frozen that we freeze now before running anything substantial. | |
1948 | */ | |
1949 | try_to_freeze(); | |
1950 | ||
1da177e4 LT |
1951 | /* |
1952 | * We are back. Now reacquire the siglock before touching | |
1953 | * last_siginfo, so that we are sure to have synchronized with | |
1954 | * any signal-sending on another CPU that wants to examine it. | |
1955 | */ | |
1956 | spin_lock_irq(¤t->sighand->siglock); | |
1957 | current->last_siginfo = NULL; | |
1958 | ||
544b2c91 TH |
1959 | /* LISTENING can be set only during STOP traps, clear it */ |
1960 | current->jobctl &= ~JOBCTL_LISTENING; | |
1961 | ||
1da177e4 LT |
1962 | /* |
1963 | * Queued signals ignored us while we were stopped for tracing. | |
1964 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1965 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1966 | */ |
b74d0deb | 1967 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1968 | } |
1969 | ||
3544d72a | 1970 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1971 | { |
1972 | siginfo_t info; | |
1973 | ||
1da177e4 | 1974 | memset(&info, 0, sizeof info); |
3544d72a | 1975 | info.si_signo = signr; |
1da177e4 | 1976 | info.si_code = exit_code; |
b488893a | 1977 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1978 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1979 | |
1980 | /* Let the debugger run. */ | |
3544d72a TH |
1981 | ptrace_stop(exit_code, why, 1, &info); |
1982 | } | |
1983 | ||
1984 | void ptrace_notify(int exit_code) | |
1985 | { | |
1986 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1987 | ||
1da177e4 | 1988 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1989 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1990 | spin_unlock_irq(¤t->sighand->siglock); |
1991 | } | |
1992 | ||
73ddff2b TH |
1993 | /** |
1994 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1995 | * @signr: signr causing group stop if initiating | |
1996 | * | |
1997 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1998 | * and participate in it. If already set, participate in the existing | |
1999 | * group stop. If participated in a group stop (and thus slept), %true is | |
2000 | * returned with siglock released. | |
2001 | * | |
2002 | * If ptraced, this function doesn't handle stop itself. Instead, | |
2003 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
2004 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
2005 | * places afterwards. | |
2006 | * | |
2007 | * CONTEXT: | |
2008 | * Must be called with @current->sighand->siglock held, which is released | |
2009 | * on %true return. | |
2010 | * | |
2011 | * RETURNS: | |
2012 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
2013 | * %true if participated in group stop. | |
1da177e4 | 2014 | */ |
73ddff2b TH |
2015 | static bool do_signal_stop(int signr) |
2016 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
2017 | { |
2018 | struct signal_struct *sig = current->signal; | |
1da177e4 | 2019 | |
a8f072c1 TH |
2020 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
2021 | unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; | |
f558b7e4 ON |
2022 | struct task_struct *t; |
2023 | ||
a8f072c1 TH |
2024 | /* signr will be recorded in task->jobctl for retries */ |
2025 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 2026 | |
a8f072c1 | 2027 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 2028 | unlikely(signal_group_exit(sig))) |
73ddff2b | 2029 | return false; |
1da177e4 | 2030 | /* |
408a37de TH |
2031 | * There is no group stop already in progress. We must |
2032 | * initiate one now. | |
2033 | * | |
2034 | * While ptraced, a task may be resumed while group stop is | |
2035 | * still in effect and then receive a stop signal and | |
2036 | * initiate another group stop. This deviates from the | |
2037 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2038 | * cause two group stops when !ptraced. That is why we |
2039 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2040 | * |
2041 | * The condition can be distinguished by testing whether | |
2042 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2043 | * group_exit_code in such case. | |
2044 | * | |
2045 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2046 | * an intervening stop signal is required to cause two | |
2047 | * continued events regardless of ptrace. | |
1da177e4 | 2048 | */ |
408a37de TH |
2049 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2050 | sig->group_exit_code = signr; | |
1da177e4 | 2051 | |
7dd3db54 TH |
2052 | sig->group_stop_count = 0; |
2053 | ||
2054 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2055 | sig->group_stop_count++; | |
1da177e4 | 2056 | |
d79fdd6d TH |
2057 | for (t = next_thread(current); t != current; |
2058 | t = next_thread(t)) { | |
1da177e4 | 2059 | /* |
a122b341 ON |
2060 | * Setting state to TASK_STOPPED for a group |
2061 | * stop is always done with the siglock held, | |
2062 | * so this check has no races. | |
1da177e4 | 2063 | */ |
7dd3db54 TH |
2064 | if (!task_is_stopped(t) && |
2065 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2066 | sig->group_stop_count++; |
fb1d910c TH |
2067 | if (likely(!(t->ptrace & PT_SEIZED))) |
2068 | signal_wake_up(t, 0); | |
2069 | else | |
2070 | ptrace_trap_notify(t); | |
a122b341 | 2071 | } |
d79fdd6d | 2072 | } |
1da177e4 | 2073 | } |
73ddff2b | 2074 | |
d21142ec | 2075 | if (likely(!current->ptrace)) { |
5224fa36 | 2076 | int notify = 0; |
1da177e4 | 2077 | |
5224fa36 TH |
2078 | /* |
2079 | * If there are no other threads in the group, or if there | |
2080 | * is a group stop in progress and we are the last to stop, | |
2081 | * report to the parent. | |
2082 | */ | |
2083 | if (task_participate_group_stop(current)) | |
2084 | notify = CLD_STOPPED; | |
2085 | ||
ae6d2ed7 | 2086 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
2087 | spin_unlock_irq(¤t->sighand->siglock); |
2088 | ||
62bcf9d9 TH |
2089 | /* |
2090 | * Notify the parent of the group stop completion. Because | |
2091 | * we're not holding either the siglock or tasklist_lock | |
2092 | * here, ptracer may attach inbetween; however, this is for | |
2093 | * group stop and should always be delivered to the real | |
2094 | * parent of the group leader. The new ptracer will get | |
2095 | * its notification when this task transitions into | |
2096 | * TASK_TRACED. | |
2097 | */ | |
5224fa36 TH |
2098 | if (notify) { |
2099 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2100 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2101 | read_unlock(&tasklist_lock); |
2102 | } | |
2103 | ||
2104 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
2105 | schedule(); | |
73ddff2b | 2106 | return true; |
d79fdd6d | 2107 | } else { |
73ddff2b TH |
2108 | /* |
2109 | * While ptraced, group stop is handled by STOP trap. | |
2110 | * Schedule it and let the caller deal with it. | |
2111 | */ | |
2112 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2113 | return false; | |
ae6d2ed7 | 2114 | } |
73ddff2b | 2115 | } |
1da177e4 | 2116 | |
73ddff2b TH |
2117 | /** |
2118 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2119 | * | |
3544d72a TH |
2120 | * When PT_SEIZED, it's used for both group stop and explicit |
2121 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2122 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2123 | * the stop signal; otherwise, %SIGTRAP. | |
2124 | * | |
2125 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2126 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2127 | * |
2128 | * CONTEXT: | |
2129 | * Must be called with @current->sighand->siglock held, which may be | |
2130 | * released and re-acquired before returning with intervening sleep. | |
2131 | */ | |
2132 | static void do_jobctl_trap(void) | |
2133 | { | |
3544d72a | 2134 | struct signal_struct *signal = current->signal; |
73ddff2b | 2135 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2136 | |
3544d72a TH |
2137 | if (current->ptrace & PT_SEIZED) { |
2138 | if (!signal->group_stop_count && | |
2139 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2140 | signr = SIGTRAP; | |
2141 | WARN_ON_ONCE(!signr); | |
2142 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2143 | CLD_STOPPED); | |
2144 | } else { | |
2145 | WARN_ON_ONCE(!signr); | |
2146 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2147 | current->exit_code = 0; | |
ae6d2ed7 | 2148 | } |
1da177e4 LT |
2149 | } |
2150 | ||
18c98b65 RM |
2151 | static int ptrace_signal(int signr, siginfo_t *info, |
2152 | struct pt_regs *regs, void *cookie) | |
2153 | { | |
18c98b65 | 2154 | ptrace_signal_deliver(regs, cookie); |
8a352418 ON |
2155 | /* |
2156 | * We do not check sig_kernel_stop(signr) but set this marker | |
2157 | * unconditionally because we do not know whether debugger will | |
2158 | * change signr. This flag has no meaning unless we are going | |
2159 | * to stop after return from ptrace_stop(). In this case it will | |
2160 | * be checked in do_signal_stop(), we should only stop if it was | |
2161 | * not cleared by SIGCONT while we were sleeping. See also the | |
2162 | * comment in dequeue_signal(). | |
2163 | */ | |
2164 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2165 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2166 | |
2167 | /* We're back. Did the debugger cancel the sig? */ | |
2168 | signr = current->exit_code; | |
2169 | if (signr == 0) | |
2170 | return signr; | |
2171 | ||
2172 | current->exit_code = 0; | |
2173 | ||
5aba085e RD |
2174 | /* |
2175 | * Update the siginfo structure if the signal has | |
2176 | * changed. If the debugger wanted something | |
2177 | * specific in the siginfo structure then it should | |
2178 | * have updated *info via PTRACE_SETSIGINFO. | |
2179 | */ | |
18c98b65 RM |
2180 | if (signr != info->si_signo) { |
2181 | info->si_signo = signr; | |
2182 | info->si_errno = 0; | |
2183 | info->si_code = SI_USER; | |
6b550f94 | 2184 | rcu_read_lock(); |
18c98b65 | 2185 | info->si_pid = task_pid_vnr(current->parent); |
6b550f94 SH |
2186 | info->si_uid = map_cred_ns(__task_cred(current->parent), |
2187 | current_user_ns()); | |
2188 | rcu_read_unlock(); | |
18c98b65 RM |
2189 | } |
2190 | ||
2191 | /* If the (new) signal is now blocked, requeue it. */ | |
2192 | if (sigismember(¤t->blocked, signr)) { | |
2193 | specific_send_sig_info(signr, info, current); | |
2194 | signr = 0; | |
2195 | } | |
2196 | ||
2197 | return signr; | |
2198 | } | |
2199 | ||
1da177e4 LT |
2200 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
2201 | struct pt_regs *regs, void *cookie) | |
2202 | { | |
f6b76d4f ON |
2203 | struct sighand_struct *sighand = current->sighand; |
2204 | struct signal_struct *signal = current->signal; | |
2205 | int signr; | |
1da177e4 | 2206 | |
13b1c3d4 RM |
2207 | relock: |
2208 | /* | |
2209 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
2210 | * While in TASK_STOPPED, we were considered "frozen enough". | |
2211 | * Now that we woke up, it's crucial if we're supposed to be | |
2212 | * frozen that we freeze now before running anything substantial. | |
2213 | */ | |
fc558a74 RW |
2214 | try_to_freeze(); |
2215 | ||
f6b76d4f | 2216 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2217 | /* |
2218 | * Every stopped thread goes here after wakeup. Check to see if | |
2219 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2220 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2221 | */ | |
f6b76d4f | 2222 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2223 | int why; |
2224 | ||
2225 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2226 | why = CLD_CONTINUED; | |
2227 | else | |
2228 | why = CLD_STOPPED; | |
2229 | ||
f6b76d4f | 2230 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2231 | |
ae6d2ed7 | 2232 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2233 | |
ceb6bd67 TH |
2234 | /* |
2235 | * Notify the parent that we're continuing. This event is | |
2236 | * always per-process and doesn't make whole lot of sense | |
2237 | * for ptracers, who shouldn't consume the state via | |
2238 | * wait(2) either, but, for backward compatibility, notify | |
2239 | * the ptracer of the group leader too unless it's gonna be | |
2240 | * a duplicate. | |
2241 | */ | |
edf2ed15 | 2242 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2243 | do_notify_parent_cldstop(current, false, why); |
2244 | ||
bb3696da ON |
2245 | if (ptrace_reparented(current->group_leader)) |
2246 | do_notify_parent_cldstop(current->group_leader, | |
2247 | true, why); | |
edf2ed15 | 2248 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2249 | |
e4420551 ON |
2250 | goto relock; |
2251 | } | |
2252 | ||
1da177e4 LT |
2253 | for (;;) { |
2254 | struct k_sigaction *ka; | |
1be53963 | 2255 | |
dd1d6772 TH |
2256 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2257 | do_signal_stop(0)) | |
7bcf6a2c | 2258 | goto relock; |
1be53963 | 2259 | |
73ddff2b TH |
2260 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2261 | do_jobctl_trap(); | |
2262 | spin_unlock_irq(&sighand->siglock); | |
2263 | goto relock; | |
2264 | } | |
1da177e4 | 2265 | |
dd1d6772 | 2266 | signr = dequeue_signal(current, ¤t->blocked, info); |
7bcf6a2c | 2267 | |
dd1d6772 TH |
2268 | if (!signr) |
2269 | break; /* will return 0 */ | |
7bcf6a2c | 2270 | |
8a352418 | 2271 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
dd1d6772 TH |
2272 | signr = ptrace_signal(signr, info, |
2273 | regs, cookie); | |
2274 | if (!signr) | |
2275 | continue; | |
1da177e4 LT |
2276 | } |
2277 | ||
dd1d6772 TH |
2278 | ka = &sighand->action[signr-1]; |
2279 | ||
f9d4257e MH |
2280 | /* Trace actually delivered signals. */ |
2281 | trace_signal_deliver(signr, info, ka); | |
2282 | ||
1da177e4 LT |
2283 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2284 | continue; | |
2285 | if (ka->sa.sa_handler != SIG_DFL) { | |
2286 | /* Run the handler. */ | |
2287 | *return_ka = *ka; | |
2288 | ||
2289 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2290 | ka->sa.sa_handler = SIG_DFL; | |
2291 | ||
2292 | break; /* will return non-zero "signr" value */ | |
2293 | } | |
2294 | ||
2295 | /* | |
2296 | * Now we are doing the default action for this signal. | |
2297 | */ | |
2298 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2299 | continue; | |
2300 | ||
84d73786 | 2301 | /* |
0fbc26a6 | 2302 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2303 | * Container-init gets no signals it doesn't want from same |
2304 | * container. | |
2305 | * | |
2306 | * Note that if global/container-init sees a sig_kernel_only() | |
2307 | * signal here, the signal must have been generated internally | |
2308 | * or must have come from an ancestor namespace. In either | |
2309 | * case, the signal cannot be dropped. | |
84d73786 | 2310 | */ |
fae5fa44 | 2311 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2312 | !sig_kernel_only(signr)) |
1da177e4 LT |
2313 | continue; |
2314 | ||
2315 | if (sig_kernel_stop(signr)) { | |
2316 | /* | |
2317 | * The default action is to stop all threads in | |
2318 | * the thread group. The job control signals | |
2319 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2320 | * always works. Note that siglock needs to be | |
2321 | * dropped during the call to is_orphaned_pgrp() | |
2322 | * because of lock ordering with tasklist_lock. | |
2323 | * This allows an intervening SIGCONT to be posted. | |
2324 | * We need to check for that and bail out if necessary. | |
2325 | */ | |
2326 | if (signr != SIGSTOP) { | |
f6b76d4f | 2327 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2328 | |
2329 | /* signals can be posted during this window */ | |
2330 | ||
3e7cd6c4 | 2331 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2332 | goto relock; |
2333 | ||
f6b76d4f | 2334 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2335 | } |
2336 | ||
7bcf6a2c | 2337 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
2338 | /* It released the siglock. */ |
2339 | goto relock; | |
2340 | } | |
2341 | ||
2342 | /* | |
2343 | * We didn't actually stop, due to a race | |
2344 | * with SIGCONT or something like that. | |
2345 | */ | |
2346 | continue; | |
2347 | } | |
2348 | ||
f6b76d4f | 2349 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2350 | |
2351 | /* | |
2352 | * Anything else is fatal, maybe with a core dump. | |
2353 | */ | |
2354 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2355 | |
1da177e4 | 2356 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2357 | if (print_fatal_signals) |
7bcf6a2c | 2358 | print_fatal_signal(regs, info->si_signo); |
1da177e4 LT |
2359 | /* |
2360 | * If it was able to dump core, this kills all | |
2361 | * other threads in the group and synchronizes with | |
2362 | * their demise. If we lost the race with another | |
2363 | * thread getting here, it set group_exit_code | |
2364 | * first and our do_group_exit call below will use | |
2365 | * that value and ignore the one we pass it. | |
2366 | */ | |
7bcf6a2c | 2367 | do_coredump(info->si_signo, info->si_signo, regs); |
1da177e4 LT |
2368 | } |
2369 | ||
2370 | /* | |
2371 | * Death signals, no core dump. | |
2372 | */ | |
7bcf6a2c | 2373 | do_group_exit(info->si_signo); |
1da177e4 LT |
2374 | /* NOTREACHED */ |
2375 | } | |
f6b76d4f | 2376 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2377 | return signr; |
2378 | } | |
2379 | ||
5e6292c0 MF |
2380 | /** |
2381 | * block_sigmask - add @ka's signal mask to current->blocked | |
2382 | * @ka: action for @signr | |
2383 | * @signr: signal that has been successfully delivered | |
2384 | * | |
2385 | * This function should be called when a signal has succesfully been | |
2386 | * delivered. It adds the mask of signals for @ka to current->blocked | |
2387 | * so that they are blocked during the execution of the signal | |
2388 | * handler. In addition, @signr will be blocked unless %SA_NODEFER is | |
2389 | * set in @ka->sa.sa_flags. | |
2390 | */ | |
2391 | void block_sigmask(struct k_sigaction *ka, int signr) | |
2392 | { | |
2393 | sigset_t blocked; | |
2394 | ||
2395 | sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask); | |
2396 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
2397 | sigaddset(&blocked, signr); | |
2398 | set_current_blocked(&blocked); | |
2399 | } | |
2400 | ||
0edceb7b ON |
2401 | /* |
2402 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2403 | * group-wide signal. Other threads should be notified now to take |
2404 | * the shared signals in @which since we will not. | |
0edceb7b | 2405 | */ |
f646e227 | 2406 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2407 | { |
f646e227 | 2408 | sigset_t retarget; |
0edceb7b ON |
2409 | struct task_struct *t; |
2410 | ||
f646e227 ON |
2411 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2412 | if (sigisemptyset(&retarget)) | |
2413 | return; | |
2414 | ||
0edceb7b ON |
2415 | t = tsk; |
2416 | while_each_thread(tsk, t) { | |
fec9993d ON |
2417 | if (t->flags & PF_EXITING) |
2418 | continue; | |
2419 | ||
2420 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2421 | continue; | |
2422 | /* Remove the signals this thread can handle. */ | |
2423 | sigandsets(&retarget, &retarget, &t->blocked); | |
2424 | ||
2425 | if (!signal_pending(t)) | |
2426 | signal_wake_up(t, 0); | |
2427 | ||
2428 | if (sigisemptyset(&retarget)) | |
2429 | break; | |
0edceb7b ON |
2430 | } |
2431 | } | |
2432 | ||
d12619b5 ON |
2433 | void exit_signals(struct task_struct *tsk) |
2434 | { | |
2435 | int group_stop = 0; | |
f646e227 | 2436 | sigset_t unblocked; |
d12619b5 | 2437 | |
77e4ef99 TH |
2438 | /* |
2439 | * @tsk is about to have PF_EXITING set - lock out users which | |
2440 | * expect stable threadgroup. | |
2441 | */ | |
2442 | threadgroup_change_begin(tsk); | |
2443 | ||
5dee1707 ON |
2444 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2445 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2446 | threadgroup_change_end(tsk); |
5dee1707 | 2447 | return; |
d12619b5 ON |
2448 | } |
2449 | ||
5dee1707 | 2450 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2451 | /* |
2452 | * From now this task is not visible for group-wide signals, | |
2453 | * see wants_signal(), do_signal_stop(). | |
2454 | */ | |
2455 | tsk->flags |= PF_EXITING; | |
77e4ef99 TH |
2456 | |
2457 | threadgroup_change_end(tsk); | |
2458 | ||
5dee1707 ON |
2459 | if (!signal_pending(tsk)) |
2460 | goto out; | |
2461 | ||
f646e227 ON |
2462 | unblocked = tsk->blocked; |
2463 | signotset(&unblocked); | |
2464 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2465 | |
a8f072c1 | 2466 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2467 | task_participate_group_stop(tsk)) |
edf2ed15 | 2468 | group_stop = CLD_STOPPED; |
5dee1707 | 2469 | out: |
d12619b5 ON |
2470 | spin_unlock_irq(&tsk->sighand->siglock); |
2471 | ||
62bcf9d9 TH |
2472 | /* |
2473 | * If group stop has completed, deliver the notification. This | |
2474 | * should always go to the real parent of the group leader. | |
2475 | */ | |
ae6d2ed7 | 2476 | if (unlikely(group_stop)) { |
d12619b5 | 2477 | read_lock(&tasklist_lock); |
62bcf9d9 | 2478 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2479 | read_unlock(&tasklist_lock); |
2480 | } | |
2481 | } | |
2482 | ||
1da177e4 LT |
2483 | EXPORT_SYMBOL(recalc_sigpending); |
2484 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2485 | EXPORT_SYMBOL(flush_signals); | |
2486 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2487 | EXPORT_SYMBOL(send_sig); |
2488 | EXPORT_SYMBOL(send_sig_info); | |
2489 | EXPORT_SYMBOL(sigprocmask); | |
2490 | EXPORT_SYMBOL(block_all_signals); | |
2491 | EXPORT_SYMBOL(unblock_all_signals); | |
2492 | ||
2493 | ||
2494 | /* | |
2495 | * System call entry points. | |
2496 | */ | |
2497 | ||
41c57892 RD |
2498 | /** |
2499 | * sys_restart_syscall - restart a system call | |
2500 | */ | |
754fe8d2 | 2501 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2502 | { |
2503 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2504 | return restart->fn(restart); | |
2505 | } | |
2506 | ||
2507 | long do_no_restart_syscall(struct restart_block *param) | |
2508 | { | |
2509 | return -EINTR; | |
2510 | } | |
2511 | ||
b182801a ON |
2512 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2513 | { | |
2514 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2515 | sigset_t newblocked; | |
2516 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2517 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2518 | retarget_shared_pending(tsk, &newblocked); |
2519 | } | |
2520 | tsk->blocked = *newset; | |
2521 | recalc_sigpending(); | |
2522 | } | |
2523 | ||
e6fa16ab ON |
2524 | /** |
2525 | * set_current_blocked - change current->blocked mask | |
2526 | * @newset: new mask | |
2527 | * | |
2528 | * It is wrong to change ->blocked directly, this helper should be used | |
2529 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2530 | */ |
e6fa16ab ON |
2531 | void set_current_blocked(const sigset_t *newset) |
2532 | { | |
2533 | struct task_struct *tsk = current; | |
2534 | ||
2535 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2536 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2537 | spin_unlock_irq(&tsk->sighand->siglock); |
2538 | } | |
1da177e4 LT |
2539 | |
2540 | /* | |
2541 | * This is also useful for kernel threads that want to temporarily | |
2542 | * (or permanently) block certain signals. | |
2543 | * | |
2544 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2545 | * interface happily blocks "unblockable" signals like SIGKILL | |
2546 | * and friends. | |
2547 | */ | |
2548 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2549 | { | |
73ef4aeb ON |
2550 | struct task_struct *tsk = current; |
2551 | sigset_t newset; | |
1da177e4 | 2552 | |
73ef4aeb | 2553 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2554 | if (oldset) |
73ef4aeb | 2555 | *oldset = tsk->blocked; |
a26fd335 | 2556 | |
1da177e4 LT |
2557 | switch (how) { |
2558 | case SIG_BLOCK: | |
73ef4aeb | 2559 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2560 | break; |
2561 | case SIG_UNBLOCK: | |
702a5073 | 2562 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2563 | break; |
2564 | case SIG_SETMASK: | |
73ef4aeb | 2565 | newset = *set; |
1da177e4 LT |
2566 | break; |
2567 | default: | |
73ef4aeb | 2568 | return -EINVAL; |
1da177e4 | 2569 | } |
a26fd335 | 2570 | |
e6fa16ab | 2571 | set_current_blocked(&newset); |
73ef4aeb | 2572 | return 0; |
1da177e4 LT |
2573 | } |
2574 | ||
41c57892 RD |
2575 | /** |
2576 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2577 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2578 | * @nset: stores pending signals |
41c57892 RD |
2579 | * @oset: previous value of signal mask if non-null |
2580 | * @sigsetsize: size of sigset_t type | |
2581 | */ | |
bb7efee2 | 2582 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2583 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2584 | { |
1da177e4 | 2585 | sigset_t old_set, new_set; |
bb7efee2 | 2586 | int error; |
1da177e4 LT |
2587 | |
2588 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2589 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2590 | return -EINVAL; |
1da177e4 | 2591 | |
bb7efee2 ON |
2592 | old_set = current->blocked; |
2593 | ||
2594 | if (nset) { | |
2595 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2596 | return -EFAULT; | |
1da177e4 LT |
2597 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2598 | ||
bb7efee2 | 2599 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2600 | if (error) |
bb7efee2 ON |
2601 | return error; |
2602 | } | |
1da177e4 | 2603 | |
bb7efee2 ON |
2604 | if (oset) { |
2605 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2606 | return -EFAULT; | |
1da177e4 | 2607 | } |
bb7efee2 ON |
2608 | |
2609 | return 0; | |
1da177e4 LT |
2610 | } |
2611 | ||
2612 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2613 | { | |
2614 | long error = -EINVAL; | |
2615 | sigset_t pending; | |
2616 | ||
2617 | if (sigsetsize > sizeof(sigset_t)) | |
2618 | goto out; | |
2619 | ||
2620 | spin_lock_irq(¤t->sighand->siglock); | |
2621 | sigorsets(&pending, ¤t->pending.signal, | |
2622 | ¤t->signal->shared_pending.signal); | |
2623 | spin_unlock_irq(¤t->sighand->siglock); | |
2624 | ||
2625 | /* Outside the lock because only this thread touches it. */ | |
2626 | sigandsets(&pending, ¤t->blocked, &pending); | |
2627 | ||
2628 | error = -EFAULT; | |
2629 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2630 | error = 0; | |
2631 | ||
2632 | out: | |
2633 | return error; | |
5aba085e | 2634 | } |
1da177e4 | 2635 | |
41c57892 RD |
2636 | /** |
2637 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2638 | * while blocked | |
2639 | * @set: stores pending signals | |
2640 | * @sigsetsize: size of sigset_t type or larger | |
2641 | */ | |
17da2bd9 | 2642 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize) |
1da177e4 LT |
2643 | { |
2644 | return do_sigpending(set, sigsetsize); | |
2645 | } | |
2646 | ||
2647 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2648 | ||
2649 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2650 | { | |
2651 | int err; | |
2652 | ||
2653 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2654 | return -EFAULT; | |
2655 | if (from->si_code < 0) | |
2656 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2657 | ? -EFAULT : 0; | |
2658 | /* | |
2659 | * If you change siginfo_t structure, please be sure | |
2660 | * this code is fixed accordingly. | |
fba2afaa DL |
2661 | * Please remember to update the signalfd_copyinfo() function |
2662 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2663 | * It should never copy any pad contained in the structure |
2664 | * to avoid security leaks, but must copy the generic | |
2665 | * 3 ints plus the relevant union member. | |
2666 | */ | |
2667 | err = __put_user(from->si_signo, &to->si_signo); | |
2668 | err |= __put_user(from->si_errno, &to->si_errno); | |
2669 | err |= __put_user((short)from->si_code, &to->si_code); | |
2670 | switch (from->si_code & __SI_MASK) { | |
2671 | case __SI_KILL: | |
2672 | err |= __put_user(from->si_pid, &to->si_pid); | |
2673 | err |= __put_user(from->si_uid, &to->si_uid); | |
2674 | break; | |
2675 | case __SI_TIMER: | |
2676 | err |= __put_user(from->si_tid, &to->si_tid); | |
2677 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2678 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2679 | break; | |
2680 | case __SI_POLL: | |
2681 | err |= __put_user(from->si_band, &to->si_band); | |
2682 | err |= __put_user(from->si_fd, &to->si_fd); | |
2683 | break; | |
2684 | case __SI_FAULT: | |
2685 | err |= __put_user(from->si_addr, &to->si_addr); | |
2686 | #ifdef __ARCH_SI_TRAPNO | |
2687 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2688 | #endif |
2689 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2690 | /* |
a337fdac | 2691 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2692 | * so check explicitly for the right codes here. |
a337fdac AK |
2693 | */ |
2694 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2695 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2696 | #endif |
2697 | break; | |
2698 | case __SI_CHLD: | |
2699 | err |= __put_user(from->si_pid, &to->si_pid); | |
2700 | err |= __put_user(from->si_uid, &to->si_uid); | |
2701 | err |= __put_user(from->si_status, &to->si_status); | |
2702 | err |= __put_user(from->si_utime, &to->si_utime); | |
2703 | err |= __put_user(from->si_stime, &to->si_stime); | |
2704 | break; | |
2705 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2706 | case __SI_MESGQ: /* But this is */ | |
2707 | err |= __put_user(from->si_pid, &to->si_pid); | |
2708 | err |= __put_user(from->si_uid, &to->si_uid); | |
2709 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2710 | break; | |
2711 | default: /* this is just in case for now ... */ | |
2712 | err |= __put_user(from->si_pid, &to->si_pid); | |
2713 | err |= __put_user(from->si_uid, &to->si_uid); | |
2714 | break; | |
2715 | } | |
2716 | return err; | |
2717 | } | |
2718 | ||
2719 | #endif | |
2720 | ||
943df148 ON |
2721 | /** |
2722 | * do_sigtimedwait - wait for queued signals specified in @which | |
2723 | * @which: queued signals to wait for | |
2724 | * @info: if non-null, the signal's siginfo is returned here | |
2725 | * @ts: upper bound on process time suspension | |
2726 | */ | |
2727 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info, | |
2728 | const struct timespec *ts) | |
2729 | { | |
2730 | struct task_struct *tsk = current; | |
2731 | long timeout = MAX_SCHEDULE_TIMEOUT; | |
2732 | sigset_t mask = *which; | |
2733 | int sig; | |
2734 | ||
2735 | if (ts) { | |
2736 | if (!timespec_valid(ts)) | |
2737 | return -EINVAL; | |
2738 | timeout = timespec_to_jiffies(ts); | |
2739 | /* | |
2740 | * We can be close to the next tick, add another one | |
2741 | * to ensure we will wait at least the time asked for. | |
2742 | */ | |
2743 | if (ts->tv_sec || ts->tv_nsec) | |
2744 | timeout++; | |
2745 | } | |
2746 | ||
2747 | /* | |
2748 | * Invert the set of allowed signals to get those we want to block. | |
2749 | */ | |
2750 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2751 | signotset(&mask); | |
2752 | ||
2753 | spin_lock_irq(&tsk->sighand->siglock); | |
2754 | sig = dequeue_signal(tsk, &mask, info); | |
2755 | if (!sig && timeout) { | |
2756 | /* | |
2757 | * None ready, temporarily unblock those we're interested | |
2758 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2759 | * they arrive. Unblocking is always fine, we can avoid |
2760 | * set_current_blocked(). | |
943df148 ON |
2761 | */ |
2762 | tsk->real_blocked = tsk->blocked; | |
2763 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2764 | recalc_sigpending(); | |
2765 | spin_unlock_irq(&tsk->sighand->siglock); | |
2766 | ||
2767 | timeout = schedule_timeout_interruptible(timeout); | |
2768 | ||
2769 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2770 | __set_task_blocked(tsk, &tsk->real_blocked); |
943df148 | 2771 | siginitset(&tsk->real_blocked, 0); |
b182801a | 2772 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2773 | } |
2774 | spin_unlock_irq(&tsk->sighand->siglock); | |
2775 | ||
2776 | if (sig) | |
2777 | return sig; | |
2778 | return timeout ? -EINTR : -EAGAIN; | |
2779 | } | |
2780 | ||
41c57892 RD |
2781 | /** |
2782 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2783 | * in @uthese | |
2784 | * @uthese: queued signals to wait for | |
2785 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2786 | * @uts: upper bound on process time suspension | |
2787 | * @sigsetsize: size of sigset_t type | |
2788 | */ | |
17da2bd9 HC |
2789 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2790 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2791 | size_t, sigsetsize) | |
1da177e4 | 2792 | { |
1da177e4 LT |
2793 | sigset_t these; |
2794 | struct timespec ts; | |
2795 | siginfo_t info; | |
943df148 | 2796 | int ret; |
1da177e4 LT |
2797 | |
2798 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2799 | if (sigsetsize != sizeof(sigset_t)) | |
2800 | return -EINVAL; | |
2801 | ||
2802 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2803 | return -EFAULT; | |
5aba085e | 2804 | |
1da177e4 LT |
2805 | if (uts) { |
2806 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2807 | return -EFAULT; | |
1da177e4 LT |
2808 | } |
2809 | ||
943df148 | 2810 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2811 | |
943df148 ON |
2812 | if (ret > 0 && uinfo) { |
2813 | if (copy_siginfo_to_user(uinfo, &info)) | |
2814 | ret = -EFAULT; | |
1da177e4 LT |
2815 | } |
2816 | ||
2817 | return ret; | |
2818 | } | |
2819 | ||
41c57892 RD |
2820 | /** |
2821 | * sys_kill - send a signal to a process | |
2822 | * @pid: the PID of the process | |
2823 | * @sig: signal to be sent | |
2824 | */ | |
17da2bd9 | 2825 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2826 | { |
2827 | struct siginfo info; | |
2828 | ||
2829 | info.si_signo = sig; | |
2830 | info.si_errno = 0; | |
2831 | info.si_code = SI_USER; | |
b488893a | 2832 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2833 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2834 | |
2835 | return kill_something_info(sig, &info, pid); | |
2836 | } | |
2837 | ||
30b4ae8a TG |
2838 | static int |
2839 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2840 | { |
1da177e4 | 2841 | struct task_struct *p; |
30b4ae8a | 2842 | int error = -ESRCH; |
1da177e4 | 2843 | |
3547ff3a | 2844 | rcu_read_lock(); |
228ebcbe | 2845 | p = find_task_by_vpid(pid); |
b488893a | 2846 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2847 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2848 | /* |
2849 | * The null signal is a permissions and process existence | |
2850 | * probe. No signal is actually delivered. | |
2851 | */ | |
4a30debf ON |
2852 | if (!error && sig) { |
2853 | error = do_send_sig_info(sig, info, p, false); | |
2854 | /* | |
2855 | * If lock_task_sighand() failed we pretend the task | |
2856 | * dies after receiving the signal. The window is tiny, | |
2857 | * and the signal is private anyway. | |
2858 | */ | |
2859 | if (unlikely(error == -ESRCH)) | |
2860 | error = 0; | |
1da177e4 LT |
2861 | } |
2862 | } | |
3547ff3a | 2863 | rcu_read_unlock(); |
6dd69f10 | 2864 | |
1da177e4 LT |
2865 | return error; |
2866 | } | |
2867 | ||
30b4ae8a TG |
2868 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2869 | { | |
2870 | struct siginfo info; | |
2871 | ||
2872 | info.si_signo = sig; | |
2873 | info.si_errno = 0; | |
2874 | info.si_code = SI_TKILL; | |
2875 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 2876 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
2877 | |
2878 | return do_send_specific(tgid, pid, sig, &info); | |
2879 | } | |
2880 | ||
6dd69f10 VL |
2881 | /** |
2882 | * sys_tgkill - send signal to one specific thread | |
2883 | * @tgid: the thread group ID of the thread | |
2884 | * @pid: the PID of the thread | |
2885 | * @sig: signal to be sent | |
2886 | * | |
72fd4a35 | 2887 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2888 | * exists but it's not belonging to the target process anymore. This |
2889 | * method solves the problem of threads exiting and PIDs getting reused. | |
2890 | */ | |
a5f8fa9e | 2891 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2892 | { |
2893 | /* This is only valid for single tasks */ | |
2894 | if (pid <= 0 || tgid <= 0) | |
2895 | return -EINVAL; | |
2896 | ||
2897 | return do_tkill(tgid, pid, sig); | |
2898 | } | |
2899 | ||
41c57892 RD |
2900 | /** |
2901 | * sys_tkill - send signal to one specific task | |
2902 | * @pid: the PID of the task | |
2903 | * @sig: signal to be sent | |
2904 | * | |
1da177e4 LT |
2905 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2906 | */ | |
a5f8fa9e | 2907 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2908 | { |
1da177e4 LT |
2909 | /* This is only valid for single tasks */ |
2910 | if (pid <= 0) | |
2911 | return -EINVAL; | |
2912 | ||
6dd69f10 | 2913 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2914 | } |
2915 | ||
41c57892 RD |
2916 | /** |
2917 | * sys_rt_sigqueueinfo - send signal information to a signal | |
2918 | * @pid: the PID of the thread | |
2919 | * @sig: signal to be sent | |
2920 | * @uinfo: signal info to be sent | |
2921 | */ | |
a5f8fa9e HC |
2922 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2923 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2924 | { |
2925 | siginfo_t info; | |
2926 | ||
2927 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2928 | return -EFAULT; | |
2929 | ||
2930 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2931 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2932 | */ | |
243b422a | 2933 | if (info.si_code >= 0 || info.si_code == SI_TKILL) { |
da48524e JT |
2934 | /* We used to allow any < 0 si_code */ |
2935 | WARN_ON_ONCE(info.si_code < 0); | |
1da177e4 | 2936 | return -EPERM; |
da48524e | 2937 | } |
1da177e4 LT |
2938 | info.si_signo = sig; |
2939 | ||
2940 | /* POSIX.1b doesn't mention process groups. */ | |
2941 | return kill_proc_info(sig, &info, pid); | |
2942 | } | |
2943 | ||
62ab4505 TG |
2944 | long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
2945 | { | |
2946 | /* This is only valid for single tasks */ | |
2947 | if (pid <= 0 || tgid <= 0) | |
2948 | return -EINVAL; | |
2949 | ||
2950 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2951 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2952 | */ | |
243b422a | 2953 | if (info->si_code >= 0 || info->si_code == SI_TKILL) { |
da48524e JT |
2954 | /* We used to allow any < 0 si_code */ |
2955 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 2956 | return -EPERM; |
da48524e | 2957 | } |
62ab4505 TG |
2958 | info->si_signo = sig; |
2959 | ||
2960 | return do_send_specific(tgid, pid, sig, info); | |
2961 | } | |
2962 | ||
2963 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
2964 | siginfo_t __user *, uinfo) | |
2965 | { | |
2966 | siginfo_t info; | |
2967 | ||
2968 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2969 | return -EFAULT; | |
2970 | ||
2971 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
2972 | } | |
2973 | ||
88531f72 | 2974 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 2975 | { |
93585eea | 2976 | struct task_struct *t = current; |
1da177e4 | 2977 | struct k_sigaction *k; |
71fabd5e | 2978 | sigset_t mask; |
1da177e4 | 2979 | |
7ed20e1a | 2980 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2981 | return -EINVAL; |
2982 | ||
93585eea | 2983 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
2984 | |
2985 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2986 | if (oact) |
2987 | *oact = *k; | |
2988 | ||
2989 | if (act) { | |
9ac95f2f ON |
2990 | sigdelsetmask(&act->sa.sa_mask, |
2991 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2992 | *k = *act; |
1da177e4 LT |
2993 | /* |
2994 | * POSIX 3.3.1.3: | |
2995 | * "Setting a signal action to SIG_IGN for a signal that is | |
2996 | * pending shall cause the pending signal to be discarded, | |
2997 | * whether or not it is blocked." | |
2998 | * | |
2999 | * "Setting a signal action to SIG_DFL for a signal that is | |
3000 | * pending and whose default action is to ignore the signal | |
3001 | * (for example, SIGCHLD), shall cause the pending signal to | |
3002 | * be discarded, whether or not it is blocked" | |
3003 | */ | |
35de254d | 3004 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
3005 | sigemptyset(&mask); |
3006 | sigaddset(&mask, sig); | |
3007 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 3008 | do { |
71fabd5e | 3009 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
3010 | t = next_thread(t); |
3011 | } while (t != current); | |
1da177e4 | 3012 | } |
1da177e4 LT |
3013 | } |
3014 | ||
3015 | spin_unlock_irq(¤t->sighand->siglock); | |
3016 | return 0; | |
3017 | } | |
3018 | ||
3019 | int | |
3020 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
3021 | { | |
3022 | stack_t oss; | |
3023 | int error; | |
3024 | ||
0083fc2c LT |
3025 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
3026 | oss.ss_size = current->sas_ss_size; | |
3027 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
3028 | |
3029 | if (uss) { | |
3030 | void __user *ss_sp; | |
3031 | size_t ss_size; | |
3032 | int ss_flags; | |
3033 | ||
3034 | error = -EFAULT; | |
0dd8486b LT |
3035 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
3036 | goto out; | |
3037 | error = __get_user(ss_sp, &uss->ss_sp) | | |
3038 | __get_user(ss_flags, &uss->ss_flags) | | |
3039 | __get_user(ss_size, &uss->ss_size); | |
3040 | if (error) | |
1da177e4 LT |
3041 | goto out; |
3042 | ||
3043 | error = -EPERM; | |
3044 | if (on_sig_stack(sp)) | |
3045 | goto out; | |
3046 | ||
3047 | error = -EINVAL; | |
3048 | /* | |
5aba085e | 3049 | * Note - this code used to test ss_flags incorrectly: |
1da177e4 LT |
3050 | * old code may have been written using ss_flags==0 |
3051 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
3052 | * way that worked) - this fix preserves that older | |
5aba085e | 3053 | * mechanism. |
1da177e4 LT |
3054 | */ |
3055 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
3056 | goto out; | |
3057 | ||
3058 | if (ss_flags == SS_DISABLE) { | |
3059 | ss_size = 0; | |
3060 | ss_sp = NULL; | |
3061 | } else { | |
3062 | error = -ENOMEM; | |
3063 | if (ss_size < MINSIGSTKSZ) | |
3064 | goto out; | |
3065 | } | |
3066 | ||
3067 | current->sas_ss_sp = (unsigned long) ss_sp; | |
3068 | current->sas_ss_size = ss_size; | |
3069 | } | |
3070 | ||
0083fc2c | 3071 | error = 0; |
1da177e4 LT |
3072 | if (uoss) { |
3073 | error = -EFAULT; | |
0083fc2c | 3074 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 3075 | goto out; |
0083fc2c LT |
3076 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
3077 | __put_user(oss.ss_size, &uoss->ss_size) | | |
3078 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
3079 | } |
3080 | ||
1da177e4 LT |
3081 | out: |
3082 | return error; | |
3083 | } | |
3084 | ||
3085 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3086 | ||
41c57892 RD |
3087 | /** |
3088 | * sys_sigpending - examine pending signals | |
3089 | * @set: where mask of pending signal is returned | |
3090 | */ | |
b290ebe2 | 3091 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 LT |
3092 | { |
3093 | return do_sigpending(set, sizeof(*set)); | |
3094 | } | |
3095 | ||
3096 | #endif | |
3097 | ||
3098 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3099 | /** |
3100 | * sys_sigprocmask - examine and change blocked signals | |
3101 | * @how: whether to add, remove, or set signals | |
b013c399 | 3102 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3103 | * @oset: previous value of signal mask if non-null |
3104 | * | |
5aba085e RD |
3105 | * Some platforms have their own version with special arguments; |
3106 | * others support only sys_rt_sigprocmask. | |
3107 | */ | |
1da177e4 | 3108 | |
b013c399 | 3109 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3110 | old_sigset_t __user *, oset) |
1da177e4 | 3111 | { |
1da177e4 | 3112 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3113 | sigset_t new_blocked; |
1da177e4 | 3114 | |
b013c399 | 3115 | old_set = current->blocked.sig[0]; |
1da177e4 | 3116 | |
b013c399 ON |
3117 | if (nset) { |
3118 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3119 | return -EFAULT; | |
1da177e4 LT |
3120 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); |
3121 | ||
2e4f7c77 | 3122 | new_blocked = current->blocked; |
1da177e4 | 3123 | |
1da177e4 | 3124 | switch (how) { |
1da177e4 | 3125 | case SIG_BLOCK: |
2e4f7c77 | 3126 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3127 | break; |
3128 | case SIG_UNBLOCK: | |
2e4f7c77 | 3129 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3130 | break; |
3131 | case SIG_SETMASK: | |
2e4f7c77 | 3132 | new_blocked.sig[0] = new_set; |
1da177e4 | 3133 | break; |
2e4f7c77 ON |
3134 | default: |
3135 | return -EINVAL; | |
1da177e4 LT |
3136 | } |
3137 | ||
2e4f7c77 | 3138 | set_current_blocked(&new_blocked); |
b013c399 ON |
3139 | } |
3140 | ||
3141 | if (oset) { | |
1da177e4 | 3142 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3143 | return -EFAULT; |
1da177e4 | 3144 | } |
b013c399 ON |
3145 | |
3146 | return 0; | |
1da177e4 LT |
3147 | } |
3148 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3149 | ||
3150 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
41c57892 RD |
3151 | /** |
3152 | * sys_rt_sigaction - alter an action taken by a process | |
3153 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3154 | * @act: new sigaction |
3155 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3156 | * @sigsetsize: size of sigset_t type |
3157 | */ | |
d4e82042 HC |
3158 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3159 | const struct sigaction __user *, act, | |
3160 | struct sigaction __user *, oact, | |
3161 | size_t, sigsetsize) | |
1da177e4 LT |
3162 | { |
3163 | struct k_sigaction new_sa, old_sa; | |
3164 | int ret = -EINVAL; | |
3165 | ||
3166 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3167 | if (sigsetsize != sizeof(sigset_t)) | |
3168 | goto out; | |
3169 | ||
3170 | if (act) { | |
3171 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3172 | return -EFAULT; | |
3173 | } | |
3174 | ||
3175 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3176 | ||
3177 | if (!ret && oact) { | |
3178 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3179 | return -EFAULT; | |
3180 | } | |
3181 | out: | |
3182 | return ret; | |
3183 | } | |
3184 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
3185 | ||
3186 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
3187 | ||
3188 | /* | |
3189 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3190 | */ | |
a5f8fa9e | 3191 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3192 | { |
3193 | /* SMP safe */ | |
3194 | return current->blocked.sig[0]; | |
3195 | } | |
3196 | ||
a5f8fa9e | 3197 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3198 | { |
c1095c6d ON |
3199 | int old = current->blocked.sig[0]; |
3200 | sigset_t newset; | |
1da177e4 | 3201 | |
c1095c6d ON |
3202 | siginitset(&newset, newmask & ~(sigmask(SIGKILL) | sigmask(SIGSTOP))); |
3203 | set_current_blocked(&newset); | |
1da177e4 LT |
3204 | |
3205 | return old; | |
3206 | } | |
3207 | #endif /* __ARCH_WANT_SGETMASK */ | |
3208 | ||
3209 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3210 | /* | |
3211 | * For backwards compatibility. Functionality superseded by sigaction. | |
3212 | */ | |
a5f8fa9e | 3213 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3214 | { |
3215 | struct k_sigaction new_sa, old_sa; | |
3216 | int ret; | |
3217 | ||
3218 | new_sa.sa.sa_handler = handler; | |
3219 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3220 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3221 | |
3222 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3223 | ||
3224 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3225 | } | |
3226 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3227 | ||
3228 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3229 | ||
a5f8fa9e | 3230 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3231 | { |
d92fcf05 ON |
3232 | while (!signal_pending(current)) { |
3233 | current->state = TASK_INTERRUPTIBLE; | |
3234 | schedule(); | |
3235 | } | |
1da177e4 LT |
3236 | return -ERESTARTNOHAND; |
3237 | } | |
3238 | ||
3239 | #endif | |
3240 | ||
150256d8 | 3241 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
41c57892 RD |
3242 | /** |
3243 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3244 | * @unewset value until a signal is received | |
3245 | * @unewset: new signal mask value | |
3246 | * @sigsetsize: size of sigset_t type | |
3247 | */ | |
d4e82042 | 3248 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3249 | { |
3250 | sigset_t newset; | |
3251 | ||
3252 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3253 | if (sigsetsize != sizeof(sigset_t)) | |
3254 | return -EINVAL; | |
3255 | ||
3256 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3257 | return -EFAULT; | |
3258 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
3259 | ||
150256d8 | 3260 | current->saved_sigmask = current->blocked; |
c1095c6d | 3261 | set_current_blocked(&newset); |
150256d8 DW |
3262 | |
3263 | current->state = TASK_INTERRUPTIBLE; | |
3264 | schedule(); | |
4e4c22c7 | 3265 | set_restore_sigmask(); |
150256d8 DW |
3266 | return -ERESTARTNOHAND; |
3267 | } | |
3268 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
3269 | ||
f269fdd1 DH |
3270 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
3271 | { | |
3272 | return NULL; | |
3273 | } | |
3274 | ||
1da177e4 LT |
3275 | void __init signals_init(void) |
3276 | { | |
0a31bd5f | 3277 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3278 | } |
67fc4e0c JW |
3279 | |
3280 | #ifdef CONFIG_KGDB_KDB | |
3281 | #include <linux/kdb.h> | |
3282 | /* | |
3283 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3284 | * signal internals. This function checks if the required locks are | |
3285 | * available before calling the main signal code, to avoid kdb | |
3286 | * deadlocks. | |
3287 | */ | |
3288 | void | |
3289 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3290 | { | |
3291 | static struct task_struct *kdb_prev_t; | |
3292 | int sig, new_t; | |
3293 | if (!spin_trylock(&t->sighand->siglock)) { | |
3294 | kdb_printf("Can't do kill command now.\n" | |
3295 | "The sigmask lock is held somewhere else in " | |
3296 | "kernel, try again later\n"); | |
3297 | return; | |
3298 | } | |
3299 | spin_unlock(&t->sighand->siglock); | |
3300 | new_t = kdb_prev_t != t; | |
3301 | kdb_prev_t = t; | |
3302 | if (t->state != TASK_RUNNING && new_t) { | |
3303 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3304 | "kdb risks deadlock\n" | |
3305 | "on the run queue locks. " | |
3306 | "The signal has _not_ been sent.\n" | |
3307 | "Reissue the kill command if you want to risk " | |
3308 | "the deadlock.\n"); | |
3309 | return; | |
3310 | } | |
3311 | sig = info->si_signo; | |
3312 | if (send_sig_info(sig, info, t)) | |
3313 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3314 | sig, t->pid); | |
3315 | else | |
3316 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3317 | } | |
3318 | #endif /* CONFIG_KGDB_KDB */ |