Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 | 13 | #include <linux/slab.h> |
9984de1a | 14 | #include <linux/export.h> |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
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> |
0326f5a9 | 32 | #include <linux/uprobes.h> |
d1eb650f MH |
33 | #define CREATE_TRACE_POINTS |
34 | #include <trace/events/signal.h> | |
84d73786 | 35 | |
1da177e4 LT |
36 | #include <asm/param.h> |
37 | #include <asm/uaccess.h> | |
38 | #include <asm/unistd.h> | |
39 | #include <asm/siginfo.h> | |
d550bbd4 | 40 | #include <asm/cacheflush.h> |
e1396065 | 41 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
42 | |
43 | /* | |
44 | * SLAB caches for signal bits. | |
45 | */ | |
46 | ||
e18b890b | 47 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 48 | |
f84d49b2 NO |
49 | int print_fatal_signals __read_mostly; |
50 | ||
35de254d | 51 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 52 | { |
35de254d RM |
53 | return t->sighand->action[sig - 1].sa.sa_handler; |
54 | } | |
93585eea | 55 | |
35de254d RM |
56 | static int sig_handler_ignored(void __user *handler, int sig) |
57 | { | |
93585eea | 58 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
59 | return handler == SIG_IGN || |
60 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
61 | } | |
1da177e4 | 62 | |
def8cf72 | 63 | static int sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 64 | { |
35de254d | 65 | void __user *handler; |
1da177e4 | 66 | |
f008faff ON |
67 | handler = sig_handler(t, sig); |
68 | ||
69 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
def8cf72 | 70 | handler == SIG_DFL && !force) |
f008faff ON |
71 | return 1; |
72 | ||
73 | return sig_handler_ignored(handler, sig); | |
74 | } | |
75 | ||
def8cf72 | 76 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 77 | { |
1da177e4 LT |
78 | /* |
79 | * Blocked signals are never ignored, since the | |
80 | * signal handler may change by the time it is | |
81 | * unblocked. | |
82 | */ | |
325d22df | 83 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
84 | return 0; |
85 | ||
def8cf72 | 86 | if (!sig_task_ignored(t, sig, force)) |
35de254d RM |
87 | return 0; |
88 | ||
89 | /* | |
90 | * Tracers may want to know about even ignored signals. | |
91 | */ | |
a288eecc | 92 | return !t->ptrace; |
1da177e4 LT |
93 | } |
94 | ||
95 | /* | |
96 | * Re-calculate pending state from the set of locally pending | |
97 | * signals, globally pending signals, and blocked signals. | |
98 | */ | |
99 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
100 | { | |
101 | unsigned long ready; | |
102 | long i; | |
103 | ||
104 | switch (_NSIG_WORDS) { | |
105 | default: | |
106 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
107 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
108 | break; | |
109 | ||
110 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
111 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
112 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
113 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
114 | break; | |
115 | ||
116 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
117 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
118 | break; | |
119 | ||
120 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
121 | } | |
122 | return ready != 0; | |
123 | } | |
124 | ||
125 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
126 | ||
7bb44ade | 127 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 128 | { |
3759a0d9 | 129 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 130 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 131 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 132 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
133 | return 1; |
134 | } | |
b74d0deb RM |
135 | /* |
136 | * We must never clear the flag in another thread, or in current | |
137 | * when it's possible the current syscall is returning -ERESTART*. | |
138 | * So we don't clear it here, and only callers who know they should do. | |
139 | */ | |
7bb44ade RM |
140 | return 0; |
141 | } | |
142 | ||
143 | /* | |
144 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
145 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
146 | */ | |
147 | void recalc_sigpending_and_wake(struct task_struct *t) | |
148 | { | |
149 | if (recalc_sigpending_tsk(t)) | |
150 | signal_wake_up(t, 0); | |
1da177e4 LT |
151 | } |
152 | ||
153 | void recalc_sigpending(void) | |
154 | { | |
dd1d6772 | 155 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
156 | clear_thread_flag(TIF_SIGPENDING); |
157 | ||
1da177e4 LT |
158 | } |
159 | ||
160 | /* Given the mask, find the first available signal that should be serviced. */ | |
161 | ||
a27341cd LT |
162 | #define SYNCHRONOUS_MASK \ |
163 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 164 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 165 | |
fba2afaa | 166 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
167 | { |
168 | unsigned long i, *s, *m, x; | |
169 | int sig = 0; | |
f84d49b2 | 170 | |
1da177e4 LT |
171 | s = pending->signal.sig; |
172 | m = mask->sig; | |
a27341cd LT |
173 | |
174 | /* | |
175 | * Handle the first word specially: it contains the | |
176 | * synchronous signals that need to be dequeued first. | |
177 | */ | |
178 | x = *s &~ *m; | |
179 | if (x) { | |
180 | if (x & SYNCHRONOUS_MASK) | |
181 | x &= SYNCHRONOUS_MASK; | |
182 | sig = ffz(~x) + 1; | |
183 | return sig; | |
184 | } | |
185 | ||
1da177e4 LT |
186 | switch (_NSIG_WORDS) { |
187 | default: | |
a27341cd LT |
188 | for (i = 1; i < _NSIG_WORDS; ++i) { |
189 | x = *++s &~ *++m; | |
190 | if (!x) | |
191 | continue; | |
192 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
193 | break; | |
194 | } | |
1da177e4 LT |
195 | break; |
196 | ||
a27341cd LT |
197 | case 2: |
198 | x = s[1] &~ m[1]; | |
199 | if (!x) | |
1da177e4 | 200 | break; |
a27341cd | 201 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
202 | break; |
203 | ||
a27341cd LT |
204 | case 1: |
205 | /* Nothing to do */ | |
1da177e4 LT |
206 | break; |
207 | } | |
f84d49b2 | 208 | |
1da177e4 LT |
209 | return sig; |
210 | } | |
211 | ||
f84d49b2 NO |
212 | static inline void print_dropped_signal(int sig) |
213 | { | |
214 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
215 | ||
216 | if (!print_fatal_signals) | |
217 | return; | |
218 | ||
219 | if (!__ratelimit(&ratelimit_state)) | |
220 | return; | |
221 | ||
222 | printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", | |
223 | current->comm, current->pid, sig); | |
224 | } | |
225 | ||
d79fdd6d | 226 | /** |
7dd3db54 | 227 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 228 | * @task: target task |
7dd3db54 | 229 | * @mask: pending bits to set |
d79fdd6d | 230 | * |
7dd3db54 TH |
231 | * Clear @mask from @task->jobctl. @mask must be subset of |
232 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
233 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
234 | * cleared. If @task is already being killed or exiting, this function | |
235 | * becomes noop. | |
236 | * | |
237 | * CONTEXT: | |
238 | * Must be called with @task->sighand->siglock held. | |
239 | * | |
240 | * RETURNS: | |
241 | * %true if @mask is set, %false if made noop because @task was dying. | |
242 | */ | |
243 | bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask) | |
244 | { | |
245 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
246 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
247 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
248 | ||
249 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
250 | return false; | |
251 | ||
252 | if (mask & JOBCTL_STOP_SIGMASK) | |
253 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
254 | ||
255 | task->jobctl |= mask; | |
256 | return true; | |
257 | } | |
258 | ||
d79fdd6d | 259 | /** |
a8f072c1 | 260 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
261 | * @task: target task |
262 | * | |
a8f072c1 TH |
263 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
264 | * Clear it and wake up the ptracer. Note that we don't need any further | |
265 | * locking. @task->siglock guarantees that @task->parent points to the | |
266 | * ptracer. | |
d79fdd6d TH |
267 | * |
268 | * CONTEXT: | |
269 | * Must be called with @task->sighand->siglock held. | |
270 | */ | |
73ddff2b | 271 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 272 | { |
a8f072c1 TH |
273 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
274 | task->jobctl &= ~JOBCTL_TRAPPING; | |
62c124ff | 275 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
276 | } |
277 | } | |
278 | ||
e5c1902e | 279 | /** |
3759a0d9 | 280 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 281 | * @task: target task |
3759a0d9 | 282 | * @mask: pending bits to clear |
e5c1902e | 283 | * |
3759a0d9 TH |
284 | * Clear @mask from @task->jobctl. @mask must be subset of |
285 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
286 | * STOP bits are cleared together. | |
e5c1902e | 287 | * |
6dfca329 TH |
288 | * If clearing of @mask leaves no stop or trap pending, this function calls |
289 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
290 | * |
291 | * CONTEXT: | |
292 | * Must be called with @task->sighand->siglock held. | |
293 | */ | |
3759a0d9 | 294 | void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask) |
e5c1902e | 295 | { |
3759a0d9 TH |
296 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
297 | ||
298 | if (mask & JOBCTL_STOP_PENDING) | |
299 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
300 | ||
301 | task->jobctl &= ~mask; | |
6dfca329 TH |
302 | |
303 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
304 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
305 | } |
306 | ||
307 | /** | |
308 | * task_participate_group_stop - participate in a group stop | |
309 | * @task: task participating in a group stop | |
310 | * | |
a8f072c1 | 311 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 312 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 313 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 314 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
315 | * |
316 | * CONTEXT: | |
317 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
318 | * |
319 | * RETURNS: | |
320 | * %true if group stop completion should be notified to the parent, %false | |
321 | * otherwise. | |
e5c1902e TH |
322 | */ |
323 | static bool task_participate_group_stop(struct task_struct *task) | |
324 | { | |
325 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 326 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 327 | |
a8f072c1 | 328 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 329 | |
3759a0d9 | 330 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
331 | |
332 | if (!consume) | |
333 | return false; | |
334 | ||
335 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
336 | sig->group_stop_count--; | |
337 | ||
244056f9 TH |
338 | /* |
339 | * Tell the caller to notify completion iff we are entering into a | |
340 | * fresh group stop. Read comment in do_signal_stop() for details. | |
341 | */ | |
342 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
e5c1902e TH |
343 | sig->flags = SIGNAL_STOP_STOPPED; |
344 | return true; | |
345 | } | |
346 | return false; | |
347 | } | |
348 | ||
c69e8d9c DH |
349 | /* |
350 | * allocate a new signal queue record | |
351 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 352 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 353 | */ |
f84d49b2 NO |
354 | static struct sigqueue * |
355 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
356 | { |
357 | struct sigqueue *q = NULL; | |
10b1fbdb | 358 | struct user_struct *user; |
1da177e4 | 359 | |
10b1fbdb | 360 | /* |
7cf7db8d TG |
361 | * Protect access to @t credentials. This can go away when all |
362 | * callers hold rcu read lock. | |
10b1fbdb | 363 | */ |
7cf7db8d | 364 | rcu_read_lock(); |
d84f4f99 | 365 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 366 | atomic_inc(&user->sigpending); |
7cf7db8d | 367 | rcu_read_unlock(); |
f84d49b2 | 368 | |
1da177e4 | 369 | if (override_rlimit || |
10b1fbdb | 370 | atomic_read(&user->sigpending) <= |
78d7d407 | 371 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 372 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
373 | } else { |
374 | print_dropped_signal(sig); | |
375 | } | |
376 | ||
1da177e4 | 377 | if (unlikely(q == NULL)) { |
10b1fbdb | 378 | atomic_dec(&user->sigpending); |
d84f4f99 | 379 | free_uid(user); |
1da177e4 LT |
380 | } else { |
381 | INIT_LIST_HEAD(&q->list); | |
382 | q->flags = 0; | |
d84f4f99 | 383 | q->user = user; |
1da177e4 | 384 | } |
d84f4f99 DH |
385 | |
386 | return q; | |
1da177e4 LT |
387 | } |
388 | ||
514a01b8 | 389 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
390 | { |
391 | if (q->flags & SIGQUEUE_PREALLOC) | |
392 | return; | |
393 | atomic_dec(&q->user->sigpending); | |
394 | free_uid(q->user); | |
395 | kmem_cache_free(sigqueue_cachep, q); | |
396 | } | |
397 | ||
6a14c5c9 | 398 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
399 | { |
400 | struct sigqueue *q; | |
401 | ||
402 | sigemptyset(&queue->signal); | |
403 | while (!list_empty(&queue->list)) { | |
404 | q = list_entry(queue->list.next, struct sigqueue , list); | |
405 | list_del_init(&q->list); | |
406 | __sigqueue_free(q); | |
407 | } | |
408 | } | |
409 | ||
410 | /* | |
411 | * Flush all pending signals for a task. | |
412 | */ | |
3bcac026 DH |
413 | void __flush_signals(struct task_struct *t) |
414 | { | |
415 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
416 | flush_sigqueue(&t->pending); | |
417 | flush_sigqueue(&t->signal->shared_pending); | |
418 | } | |
419 | ||
c81addc9 | 420 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
421 | { |
422 | unsigned long flags; | |
423 | ||
424 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
3bcac026 | 425 | __flush_signals(t); |
1da177e4 LT |
426 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
427 | } | |
428 | ||
cbaffba1 ON |
429 | static void __flush_itimer_signals(struct sigpending *pending) |
430 | { | |
431 | sigset_t signal, retain; | |
432 | struct sigqueue *q, *n; | |
433 | ||
434 | signal = pending->signal; | |
435 | sigemptyset(&retain); | |
436 | ||
437 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
438 | int sig = q->info.si_signo; | |
439 | ||
440 | if (likely(q->info.si_code != SI_TIMER)) { | |
441 | sigaddset(&retain, sig); | |
442 | } else { | |
443 | sigdelset(&signal, sig); | |
444 | list_del_init(&q->list); | |
445 | __sigqueue_free(q); | |
446 | } | |
447 | } | |
448 | ||
449 | sigorsets(&pending->signal, &signal, &retain); | |
450 | } | |
451 | ||
452 | void flush_itimer_signals(void) | |
453 | { | |
454 | struct task_struct *tsk = current; | |
455 | unsigned long flags; | |
456 | ||
457 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
458 | __flush_itimer_signals(&tsk->pending); | |
459 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
460 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
461 | } | |
462 | ||
10ab825b ON |
463 | void ignore_signals(struct task_struct *t) |
464 | { | |
465 | int i; | |
466 | ||
467 | for (i = 0; i < _NSIG; ++i) | |
468 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
469 | ||
470 | flush_signals(t); | |
471 | } | |
472 | ||
1da177e4 LT |
473 | /* |
474 | * Flush all handlers for a task. | |
475 | */ | |
476 | ||
477 | void | |
478 | flush_signal_handlers(struct task_struct *t, int force_default) | |
479 | { | |
480 | int i; | |
481 | struct k_sigaction *ka = &t->sighand->action[0]; | |
482 | for (i = _NSIG ; i != 0 ; i--) { | |
483 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
484 | ka->sa.sa_handler = SIG_DFL; | |
485 | ka->sa.sa_flags = 0; | |
486 | sigemptyset(&ka->sa.sa_mask); | |
487 | ka++; | |
488 | } | |
489 | } | |
490 | ||
abd4f750 MAS |
491 | int unhandled_signal(struct task_struct *tsk, int sig) |
492 | { | |
445a91d2 | 493 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 494 | if (is_global_init(tsk)) |
abd4f750 | 495 | return 1; |
445a91d2 | 496 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 497 | return 0; |
a288eecc TH |
498 | /* if ptraced, let the tracer determine */ |
499 | return !tsk->ptrace; | |
abd4f750 MAS |
500 | } |
501 | ||
5aba085e RD |
502 | /* |
503 | * Notify the system that a driver wants to block all signals for this | |
1da177e4 LT |
504 | * process, and wants to be notified if any signals at all were to be |
505 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
506 | * signal will be acted upon after all. If the notifier routine returns 0, | |
507 | * then then signal will be blocked. Only one block per process is | |
508 | * allowed. priv is a pointer to private data that the notifier routine | |
5aba085e RD |
509 | * can use to determine if the signal should be blocked or not. |
510 | */ | |
1da177e4 LT |
511 | void |
512 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
513 | { | |
514 | unsigned long flags; | |
515 | ||
516 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
517 | current->notifier_mask = mask; | |
518 | current->notifier_data = priv; | |
519 | current->notifier = notifier; | |
520 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
521 | } | |
522 | ||
523 | /* Notify the system that blocking has ended. */ | |
524 | ||
525 | void | |
526 | unblock_all_signals(void) | |
527 | { | |
528 | unsigned long flags; | |
529 | ||
530 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
531 | current->notifier = NULL; | |
532 | current->notifier_data = NULL; | |
533 | recalc_sigpending(); | |
534 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
535 | } | |
536 | ||
100360f0 | 537 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
538 | { |
539 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 540 | |
1da177e4 LT |
541 | /* |
542 | * Collect the siginfo appropriate to this signal. Check if | |
543 | * there is another siginfo for the same signal. | |
544 | */ | |
545 | list_for_each_entry(q, &list->list, list) { | |
546 | if (q->info.si_signo == sig) { | |
d4434207 ON |
547 | if (first) |
548 | goto still_pending; | |
1da177e4 LT |
549 | first = q; |
550 | } | |
551 | } | |
d4434207 ON |
552 | |
553 | sigdelset(&list->signal, sig); | |
554 | ||
1da177e4 | 555 | if (first) { |
d4434207 | 556 | still_pending: |
1da177e4 LT |
557 | list_del_init(&first->list); |
558 | copy_siginfo(info, &first->info); | |
559 | __sigqueue_free(first); | |
1da177e4 | 560 | } else { |
5aba085e RD |
561 | /* |
562 | * Ok, it wasn't in the queue. This must be | |
563 | * a fast-pathed signal or we must have been | |
564 | * out of queue space. So zero out the info. | |
1da177e4 | 565 | */ |
1da177e4 LT |
566 | info->si_signo = sig; |
567 | info->si_errno = 0; | |
7486e5d9 | 568 | info->si_code = SI_USER; |
1da177e4 LT |
569 | info->si_pid = 0; |
570 | info->si_uid = 0; | |
571 | } | |
1da177e4 LT |
572 | } |
573 | ||
574 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
575 | siginfo_t *info) | |
576 | { | |
27d91e07 | 577 | int sig = next_signal(pending, mask); |
1da177e4 | 578 | |
1da177e4 LT |
579 | if (sig) { |
580 | if (current->notifier) { | |
581 | if (sigismember(current->notifier_mask, sig)) { | |
582 | if (!(current->notifier)(current->notifier_data)) { | |
583 | clear_thread_flag(TIF_SIGPENDING); | |
584 | return 0; | |
585 | } | |
586 | } | |
587 | } | |
588 | ||
100360f0 | 589 | collect_signal(sig, pending, info); |
1da177e4 | 590 | } |
1da177e4 LT |
591 | |
592 | return sig; | |
593 | } | |
594 | ||
595 | /* | |
5aba085e | 596 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
597 | * expected to free it. |
598 | * | |
599 | * All callers have to hold the siglock. | |
600 | */ | |
601 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
602 | { | |
c5363d03 | 603 | int signr; |
caec4e8d BH |
604 | |
605 | /* We only dequeue private signals from ourselves, we don't let | |
606 | * signalfd steal them | |
607 | */ | |
b8fceee1 | 608 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 609 | if (!signr) { |
1da177e4 LT |
610 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
611 | mask, info); | |
8bfd9a7a TG |
612 | /* |
613 | * itimer signal ? | |
614 | * | |
615 | * itimers are process shared and we restart periodic | |
616 | * itimers in the signal delivery path to prevent DoS | |
617 | * attacks in the high resolution timer case. This is | |
5aba085e | 618 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
619 | * itimers, as the SIGALRM is a legacy signal and only |
620 | * queued once. Changing the restart behaviour to | |
621 | * restart the timer in the signal dequeue path is | |
622 | * reducing the timer noise on heavy loaded !highres | |
623 | * systems too. | |
624 | */ | |
625 | if (unlikely(signr == SIGALRM)) { | |
626 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
627 | ||
628 | if (!hrtimer_is_queued(tmr) && | |
629 | tsk->signal->it_real_incr.tv64 != 0) { | |
630 | hrtimer_forward(tmr, tmr->base->get_time(), | |
631 | tsk->signal->it_real_incr); | |
632 | hrtimer_restart(tmr); | |
633 | } | |
634 | } | |
635 | } | |
c5363d03 | 636 | |
b8fceee1 | 637 | recalc_sigpending(); |
c5363d03 PE |
638 | if (!signr) |
639 | return 0; | |
640 | ||
641 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
642 | /* |
643 | * Set a marker that we have dequeued a stop signal. Our | |
644 | * caller might release the siglock and then the pending | |
645 | * stop signal it is about to process is no longer in the | |
646 | * pending bitmasks, but must still be cleared by a SIGCONT | |
647 | * (and overruled by a SIGKILL). So those cases clear this | |
648 | * shared flag after we've set it. Note that this flag may | |
649 | * remain set after the signal we return is ignored or | |
650 | * handled. That doesn't matter because its only purpose | |
651 | * is to alert stop-signal processing code when another | |
652 | * processor has come along and cleared the flag. | |
653 | */ | |
a8f072c1 | 654 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 655 | } |
c5363d03 | 656 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
657 | /* |
658 | * Release the siglock to ensure proper locking order | |
659 | * of timer locks outside of siglocks. Note, we leave | |
660 | * irqs disabled here, since the posix-timers code is | |
661 | * about to disable them again anyway. | |
662 | */ | |
663 | spin_unlock(&tsk->sighand->siglock); | |
664 | do_schedule_next_timer(info); | |
665 | spin_lock(&tsk->sighand->siglock); | |
666 | } | |
667 | return signr; | |
668 | } | |
669 | ||
670 | /* | |
671 | * Tell a process that it has a new active signal.. | |
672 | * | |
673 | * NOTE! we rely on the previous spin_lock to | |
674 | * lock interrupts for us! We can only be called with | |
675 | * "siglock" held, and the local interrupt must | |
676 | * have been disabled when that got acquired! | |
677 | * | |
678 | * No need to set need_resched since signal event passing | |
679 | * goes through ->blocked | |
680 | */ | |
681 | void signal_wake_up(struct task_struct *t, int resume) | |
682 | { | |
683 | unsigned int mask; | |
684 | ||
685 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
686 | ||
687 | /* | |
f021a3c2 MW |
688 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
689 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
690 | * executing another processor and just now entering stopped state. |
691 | * By using wake_up_state, we ensure the process will wake up and | |
692 | * handle its death signal. | |
693 | */ | |
694 | mask = TASK_INTERRUPTIBLE; | |
695 | if (resume) | |
f021a3c2 | 696 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
697 | if (!wake_up_state(t, mask)) |
698 | kick_process(t); | |
699 | } | |
700 | ||
71fabd5e GA |
701 | /* |
702 | * Remove signals in mask from the pending set and queue. | |
703 | * Returns 1 if any signals were found. | |
704 | * | |
705 | * All callers must be holding the siglock. | |
706 | * | |
707 | * This version takes a sigset mask and looks at all signals, | |
708 | * not just those in the first mask word. | |
709 | */ | |
710 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
711 | { | |
712 | struct sigqueue *q, *n; | |
713 | sigset_t m; | |
714 | ||
715 | sigandsets(&m, mask, &s->signal); | |
716 | if (sigisemptyset(&m)) | |
717 | return 0; | |
718 | ||
702a5073 | 719 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
720 | list_for_each_entry_safe(q, n, &s->list, list) { |
721 | if (sigismember(mask, q->info.si_signo)) { | |
722 | list_del_init(&q->list); | |
723 | __sigqueue_free(q); | |
724 | } | |
725 | } | |
726 | return 1; | |
727 | } | |
1da177e4 LT |
728 | /* |
729 | * Remove signals in mask from the pending set and queue. | |
730 | * Returns 1 if any signals were found. | |
731 | * | |
732 | * All callers must be holding the siglock. | |
733 | */ | |
734 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
735 | { | |
736 | struct sigqueue *q, *n; | |
737 | ||
738 | if (!sigtestsetmask(&s->signal, mask)) | |
739 | return 0; | |
740 | ||
741 | sigdelsetmask(&s->signal, mask); | |
742 | list_for_each_entry_safe(q, n, &s->list, list) { | |
743 | if (q->info.si_signo < SIGRTMIN && | |
744 | (mask & sigmask(q->info.si_signo))) { | |
745 | list_del_init(&q->list); | |
746 | __sigqueue_free(q); | |
747 | } | |
748 | } | |
749 | return 1; | |
750 | } | |
751 | ||
614c517d ON |
752 | static inline int is_si_special(const struct siginfo *info) |
753 | { | |
754 | return info <= SEND_SIG_FORCED; | |
755 | } | |
756 | ||
757 | static inline bool si_fromuser(const struct siginfo *info) | |
758 | { | |
759 | return info == SEND_SIG_NOINFO || | |
760 | (!is_si_special(info) && SI_FROMUSER(info)); | |
761 | } | |
762 | ||
39fd3393 SH |
763 | /* |
764 | * called with RCU read lock from check_kill_permission() | |
765 | */ | |
766 | static int kill_ok_by_cred(struct task_struct *t) | |
767 | { | |
768 | const struct cred *cred = current_cred(); | |
769 | const struct cred *tcred = __task_cred(t); | |
770 | ||
5af66203 EB |
771 | if (uid_eq(cred->euid, tcred->suid) || |
772 | uid_eq(cred->euid, tcred->uid) || | |
773 | uid_eq(cred->uid, tcred->suid) || | |
774 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
775 | return 1; |
776 | ||
c4a4d603 | 777 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
778 | return 1; |
779 | ||
780 | return 0; | |
781 | } | |
782 | ||
1da177e4 LT |
783 | /* |
784 | * Bad permissions for sending the signal | |
694f690d | 785 | * - the caller must hold the RCU read lock |
1da177e4 LT |
786 | */ |
787 | static int check_kill_permission(int sig, struct siginfo *info, | |
788 | struct task_struct *t) | |
789 | { | |
2e2ba22e | 790 | struct pid *sid; |
3b5e9e53 ON |
791 | int error; |
792 | ||
7ed20e1a | 793 | if (!valid_signal(sig)) |
3b5e9e53 ON |
794 | return -EINVAL; |
795 | ||
614c517d | 796 | if (!si_fromuser(info)) |
3b5e9e53 | 797 | return 0; |
e54dc243 | 798 | |
3b5e9e53 ON |
799 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
800 | if (error) | |
1da177e4 | 801 | return error; |
3b5e9e53 | 802 | |
065add39 | 803 | if (!same_thread_group(current, t) && |
39fd3393 | 804 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
805 | switch (sig) { |
806 | case SIGCONT: | |
2e2ba22e | 807 | sid = task_session(t); |
2e2ba22e ON |
808 | /* |
809 | * We don't return the error if sid == NULL. The | |
810 | * task was unhashed, the caller must notice this. | |
811 | */ | |
812 | if (!sid || sid == task_session(current)) | |
813 | break; | |
814 | default: | |
815 | return -EPERM; | |
816 | } | |
817 | } | |
c2f0c7c3 | 818 | |
e54dc243 | 819 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
820 | } |
821 | ||
fb1d910c TH |
822 | /** |
823 | * ptrace_trap_notify - schedule trap to notify ptracer | |
824 | * @t: tracee wanting to notify tracer | |
825 | * | |
826 | * This function schedules sticky ptrace trap which is cleared on the next | |
827 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
828 | * ptracer. | |
829 | * | |
544b2c91 TH |
830 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
831 | * ptracer is listening for events, tracee is woken up so that it can | |
832 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
833 | * eventually taken without returning to userland after the existing traps | |
834 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
835 | * |
836 | * CONTEXT: | |
837 | * Must be called with @task->sighand->siglock held. | |
838 | */ | |
839 | static void ptrace_trap_notify(struct task_struct *t) | |
840 | { | |
841 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
842 | assert_spin_locked(&t->sighand->siglock); | |
843 | ||
844 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
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 | #ifdef CONFIG_USER_NS |
1024 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1025 | { | |
1026 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
1027 | return; | |
1028 | ||
1029 | if (SI_FROMKERNEL(info)) | |
1030 | return; | |
1031 | ||
078de5f7 EB |
1032 | rcu_read_lock(); |
1033 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
1034 | make_kuid(current_user_ns(), info->si_uid)); | |
1035 | rcu_read_unlock(); | |
6b550f94 SH |
1036 | } |
1037 | #else | |
1038 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1039 | { | |
1040 | return; | |
1041 | } | |
1042 | #endif | |
1043 | ||
7978b567 SB |
1044 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1045 | int group, int from_ancestor_ns) | |
1da177e4 | 1046 | { |
2ca3515a | 1047 | struct sigpending *pending; |
6e65acba | 1048 | struct sigqueue *q; |
7a0aeb14 | 1049 | int override_rlimit; |
6c303d3a | 1050 | int ret = 0, result; |
0a16b607 | 1051 | |
6e65acba | 1052 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1053 | |
6c303d3a | 1054 | result = TRACE_SIGNAL_IGNORED; |
629d362b ON |
1055 | if (!prepare_signal(sig, t, |
1056 | from_ancestor_ns || (info == SEND_SIG_FORCED))) | |
6c303d3a | 1057 | goto ret; |
2ca3515a ON |
1058 | |
1059 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
1060 | /* |
1061 | * Short-circuit ignored signals and support queuing | |
1062 | * exactly one non-rt signal, so that we can get more | |
1063 | * detailed information about the cause of the signal. | |
1064 | */ | |
6c303d3a | 1065 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1066 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1067 | goto ret; |
1068 | ||
1069 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1070 | /* |
1071 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1072 | * or SIGKILL. | |
1073 | */ | |
b67a1b9e | 1074 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1075 | goto out_set; |
1076 | ||
5aba085e RD |
1077 | /* |
1078 | * Real-time signals must be queued if sent by sigqueue, or | |
1079 | * some other real-time mechanism. It is implementation | |
1080 | * defined whether kill() does so. We attempt to do so, on | |
1081 | * the principle of least surprise, but since kill is not | |
1082 | * allowed to fail with EAGAIN when low on memory we just | |
1083 | * make sure at least one signal gets delivered and don't | |
1084 | * pass on the info struct. | |
1085 | */ | |
7a0aeb14 VN |
1086 | if (sig < SIGRTMIN) |
1087 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1088 | else | |
1089 | override_rlimit = 0; | |
1090 | ||
f84d49b2 | 1091 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1092 | override_rlimit); |
1da177e4 | 1093 | if (q) { |
2ca3515a | 1094 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1095 | switch ((unsigned long) info) { |
b67a1b9e | 1096 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1097 | q->info.si_signo = sig; |
1098 | q->info.si_errno = 0; | |
1099 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1100 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1101 | task_active_pid_ns(t)); |
078de5f7 | 1102 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1103 | break; |
b67a1b9e | 1104 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1105 | q->info.si_signo = sig; |
1106 | q->info.si_errno = 0; | |
1107 | q->info.si_code = SI_KERNEL; | |
1108 | q->info.si_pid = 0; | |
1109 | q->info.si_uid = 0; | |
1110 | break; | |
1111 | default: | |
1112 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1113 | if (from_ancestor_ns) |
1114 | q->info.si_pid = 0; | |
1da177e4 LT |
1115 | break; |
1116 | } | |
6b550f94 SH |
1117 | |
1118 | userns_fixup_signal_uid(&q->info, t); | |
1119 | ||
621d3121 | 1120 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1121 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1122 | /* | |
1123 | * Queue overflow, abort. We may abort if the | |
1124 | * signal was rt and sent by user using something | |
1125 | * other than kill(). | |
1126 | */ | |
6c303d3a ON |
1127 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1128 | ret = -EAGAIN; | |
1129 | goto ret; | |
ba005e1f MH |
1130 | } else { |
1131 | /* | |
1132 | * This is a silent loss of information. We still | |
1133 | * send the signal, but the *info bits are lost. | |
1134 | */ | |
6c303d3a | 1135 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1136 | } |
1da177e4 LT |
1137 | } |
1138 | ||
1139 | out_set: | |
53c30337 | 1140 | signalfd_notify(t, sig); |
2ca3515a | 1141 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1142 | complete_signal(sig, t, group); |
6c303d3a ON |
1143 | ret: |
1144 | trace_signal_generate(sig, info, t, group, result); | |
1145 | return ret; | |
1da177e4 LT |
1146 | } |
1147 | ||
7978b567 SB |
1148 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1149 | int group) | |
1150 | { | |
921cf9f6 SB |
1151 | int from_ancestor_ns = 0; |
1152 | ||
1153 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1154 | from_ancestor_ns = si_fromuser(info) && |
1155 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1156 | #endif |
1157 | ||
1158 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1159 | } |
1160 | ||
45807a1d IM |
1161 | static void print_fatal_signal(struct pt_regs *regs, int signr) |
1162 | { | |
1163 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 1164 | current->comm, task_pid_nr(current), signr); |
45807a1d | 1165 | |
ca5cd877 | 1166 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 1167 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
1168 | { |
1169 | int i; | |
1170 | for (i = 0; i < 16; i++) { | |
1171 | unsigned char insn; | |
1172 | ||
b45c6e76 AK |
1173 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1174 | break; | |
45807a1d IM |
1175 | printk("%02x ", insn); |
1176 | } | |
1177 | } | |
1178 | #endif | |
1179 | printk("\n"); | |
3a9f84d3 | 1180 | preempt_disable(); |
45807a1d | 1181 | show_regs(regs); |
3a9f84d3 | 1182 | preempt_enable(); |
45807a1d IM |
1183 | } |
1184 | ||
1185 | static int __init setup_print_fatal_signals(char *str) | |
1186 | { | |
1187 | get_option (&str, &print_fatal_signals); | |
1188 | ||
1189 | return 1; | |
1190 | } | |
1191 | ||
1192 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1193 | |
4cd4b6d4 PE |
1194 | int |
1195 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1196 | { | |
1197 | return send_signal(sig, info, p, 1); | |
1198 | } | |
1199 | ||
1da177e4 LT |
1200 | static int |
1201 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1202 | { | |
4cd4b6d4 | 1203 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1204 | } |
1205 | ||
4a30debf ON |
1206 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1207 | bool group) | |
1208 | { | |
1209 | unsigned long flags; | |
1210 | int ret = -ESRCH; | |
1211 | ||
1212 | if (lock_task_sighand(p, &flags)) { | |
1213 | ret = send_signal(sig, info, p, group); | |
1214 | unlock_task_sighand(p, &flags); | |
1215 | } | |
1216 | ||
1217 | return ret; | |
1218 | } | |
1219 | ||
1da177e4 LT |
1220 | /* |
1221 | * Force a signal that the process can't ignore: if necessary | |
1222 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1223 | * |
1224 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1225 | * since we do not want to have a signal handler that was blocked | |
1226 | * be invoked when user space had explicitly blocked it. | |
1227 | * | |
80fe728d ON |
1228 | * We don't want to have recursive SIGSEGV's etc, for example, |
1229 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1230 | */ |
1da177e4 LT |
1231 | int |
1232 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1233 | { | |
1234 | unsigned long int flags; | |
ae74c3b6 LT |
1235 | int ret, blocked, ignored; |
1236 | struct k_sigaction *action; | |
1da177e4 LT |
1237 | |
1238 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1239 | action = &t->sighand->action[sig-1]; |
1240 | ignored = action->sa.sa_handler == SIG_IGN; | |
1241 | blocked = sigismember(&t->blocked, sig); | |
1242 | if (blocked || ignored) { | |
1243 | action->sa.sa_handler = SIG_DFL; | |
1244 | if (blocked) { | |
1245 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1246 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1247 | } |
1da177e4 | 1248 | } |
80fe728d ON |
1249 | if (action->sa.sa_handler == SIG_DFL) |
1250 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1251 | ret = specific_send_sig_info(sig, info, t); |
1252 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1253 | ||
1254 | return ret; | |
1255 | } | |
1256 | ||
1da177e4 LT |
1257 | /* |
1258 | * Nuke all other threads in the group. | |
1259 | */ | |
09faef11 | 1260 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1261 | { |
09faef11 ON |
1262 | struct task_struct *t = p; |
1263 | int count = 0; | |
1da177e4 | 1264 | |
1da177e4 LT |
1265 | p->signal->group_stop_count = 0; |
1266 | ||
09faef11 | 1267 | while_each_thread(p, t) { |
6dfca329 | 1268 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1269 | count++; |
1270 | ||
1271 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1272 | if (t->exit_state) |
1273 | continue; | |
1da177e4 | 1274 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1275 | signal_wake_up(t, 1); |
1276 | } | |
09faef11 ON |
1277 | |
1278 | return count; | |
1da177e4 LT |
1279 | } |
1280 | ||
b8ed374e NK |
1281 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1282 | unsigned long *flags) | |
f63ee72e ON |
1283 | { |
1284 | struct sighand_struct *sighand; | |
1285 | ||
1286 | for (;;) { | |
a841796f PM |
1287 | local_irq_save(*flags); |
1288 | rcu_read_lock(); | |
f63ee72e | 1289 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1290 | if (unlikely(sighand == NULL)) { |
1291 | rcu_read_unlock(); | |
1292 | local_irq_restore(*flags); | |
f63ee72e | 1293 | break; |
a841796f | 1294 | } |
f63ee72e | 1295 | |
a841796f PM |
1296 | spin_lock(&sighand->siglock); |
1297 | if (likely(sighand == tsk->sighand)) { | |
1298 | rcu_read_unlock(); | |
f63ee72e | 1299 | break; |
a841796f PM |
1300 | } |
1301 | spin_unlock(&sighand->siglock); | |
1302 | rcu_read_unlock(); | |
1303 | local_irq_restore(*flags); | |
f63ee72e ON |
1304 | } |
1305 | ||
1306 | return sighand; | |
1307 | } | |
1308 | ||
c69e8d9c DH |
1309 | /* |
1310 | * send signal info to all the members of a group | |
c69e8d9c | 1311 | */ |
1da177e4 LT |
1312 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1313 | { | |
694f690d DH |
1314 | int ret; |
1315 | ||
1316 | rcu_read_lock(); | |
1317 | ret = check_kill_permission(sig, info, p); | |
1318 | rcu_read_unlock(); | |
f63ee72e | 1319 | |
4a30debf ON |
1320 | if (!ret && sig) |
1321 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1322 | |
1323 | return ret; | |
1324 | } | |
1325 | ||
1326 | /* | |
146a505d | 1327 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1328 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1329 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1330 | */ |
c4b92fc1 | 1331 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1332 | { |
1333 | struct task_struct *p = NULL; | |
1334 | int retval, success; | |
1335 | ||
1da177e4 LT |
1336 | success = 0; |
1337 | retval = -ESRCH; | |
c4b92fc1 | 1338 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1339 | int err = group_send_sig_info(sig, info, p); |
1340 | success |= !err; | |
1341 | retval = err; | |
c4b92fc1 | 1342 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1343 | return success ? 0 : retval; |
1344 | } | |
1345 | ||
c4b92fc1 | 1346 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1347 | { |
d36174bc | 1348 | int error = -ESRCH; |
1da177e4 LT |
1349 | struct task_struct *p; |
1350 | ||
e56d0903 | 1351 | rcu_read_lock(); |
d36174bc | 1352 | retry: |
c4b92fc1 | 1353 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1354 | if (p) { |
1da177e4 | 1355 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1356 | if (unlikely(error == -ESRCH)) |
1357 | /* | |
1358 | * The task was unhashed in between, try again. | |
1359 | * If it is dead, pid_task() will return NULL, | |
1360 | * if we race with de_thread() it will find the | |
1361 | * new leader. | |
1362 | */ | |
1363 | goto retry; | |
1364 | } | |
e56d0903 | 1365 | rcu_read_unlock(); |
6ca25b55 | 1366 | |
1da177e4 LT |
1367 | return error; |
1368 | } | |
1369 | ||
5aba085e | 1370 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1371 | { |
1372 | int error; | |
1373 | rcu_read_lock(); | |
b488893a | 1374 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1375 | rcu_read_unlock(); |
1376 | return error; | |
1377 | } | |
1378 | ||
d178bc3a SH |
1379 | static int kill_as_cred_perm(const struct cred *cred, |
1380 | struct task_struct *target) | |
1381 | { | |
1382 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1383 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1384 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1385 | return 0; |
1386 | return 1; | |
1387 | } | |
1388 | ||
2425c08b | 1389 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1390 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1391 | const struct cred *cred, u32 secid) | |
46113830 HW |
1392 | { |
1393 | int ret = -EINVAL; | |
1394 | struct task_struct *p; | |
14d8c9f3 | 1395 | unsigned long flags; |
46113830 HW |
1396 | |
1397 | if (!valid_signal(sig)) | |
1398 | return ret; | |
1399 | ||
14d8c9f3 | 1400 | rcu_read_lock(); |
2425c08b | 1401 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1402 | if (!p) { |
1403 | ret = -ESRCH; | |
1404 | goto out_unlock; | |
1405 | } | |
d178bc3a | 1406 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1407 | ret = -EPERM; |
1408 | goto out_unlock; | |
1409 | } | |
8f95dc58 DQ |
1410 | ret = security_task_kill(p, info, sig, secid); |
1411 | if (ret) | |
1412 | goto out_unlock; | |
14d8c9f3 TG |
1413 | |
1414 | if (sig) { | |
1415 | if (lock_task_sighand(p, &flags)) { | |
1416 | ret = __send_signal(sig, info, p, 1, 0); | |
1417 | unlock_task_sighand(p, &flags); | |
1418 | } else | |
1419 | ret = -ESRCH; | |
46113830 HW |
1420 | } |
1421 | out_unlock: | |
14d8c9f3 | 1422 | rcu_read_unlock(); |
46113830 HW |
1423 | return ret; |
1424 | } | |
d178bc3a | 1425 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1426 | |
1427 | /* | |
1428 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1429 | * | |
1430 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1431 | * is probably wrong. Should make it like BSD or SYSV. | |
1432 | */ | |
1433 | ||
bc64efd2 | 1434 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1435 | { |
8d42db18 | 1436 | int ret; |
d5df763b PE |
1437 | |
1438 | if (pid > 0) { | |
1439 | rcu_read_lock(); | |
1440 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1441 | rcu_read_unlock(); | |
1442 | return ret; | |
1443 | } | |
1444 | ||
1445 | read_lock(&tasklist_lock); | |
1446 | if (pid != -1) { | |
1447 | ret = __kill_pgrp_info(sig, info, | |
1448 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1449 | } else { | |
1da177e4 LT |
1450 | int retval = 0, count = 0; |
1451 | struct task_struct * p; | |
1452 | ||
1da177e4 | 1453 | for_each_process(p) { |
d25141a8 SB |
1454 | if (task_pid_vnr(p) > 1 && |
1455 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1456 | int err = group_send_sig_info(sig, info, p); |
1457 | ++count; | |
1458 | if (err != -EPERM) | |
1459 | retval = err; | |
1460 | } | |
1461 | } | |
8d42db18 | 1462 | ret = count ? retval : -ESRCH; |
1da177e4 | 1463 | } |
d5df763b PE |
1464 | read_unlock(&tasklist_lock); |
1465 | ||
8d42db18 | 1466 | return ret; |
1da177e4 LT |
1467 | } |
1468 | ||
1469 | /* | |
1470 | * These are for backward compatibility with the rest of the kernel source. | |
1471 | */ | |
1472 | ||
5aba085e | 1473 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1474 | { |
1da177e4 LT |
1475 | /* |
1476 | * Make sure legacy kernel users don't send in bad values | |
1477 | * (normal paths check this in check_kill_permission). | |
1478 | */ | |
7ed20e1a | 1479 | if (!valid_signal(sig)) |
1da177e4 LT |
1480 | return -EINVAL; |
1481 | ||
4a30debf | 1482 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1483 | } |
1484 | ||
b67a1b9e ON |
1485 | #define __si_special(priv) \ |
1486 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1487 | ||
1da177e4 LT |
1488 | int |
1489 | send_sig(int sig, struct task_struct *p, int priv) | |
1490 | { | |
b67a1b9e | 1491 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1492 | } |
1493 | ||
1da177e4 LT |
1494 | void |
1495 | force_sig(int sig, struct task_struct *p) | |
1496 | { | |
b67a1b9e | 1497 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1498 | } |
1499 | ||
1500 | /* | |
1501 | * When things go south during signal handling, we | |
1502 | * will force a SIGSEGV. And if the signal that caused | |
1503 | * the problem was already a SIGSEGV, we'll want to | |
1504 | * make sure we don't even try to deliver the signal.. | |
1505 | */ | |
1506 | int | |
1507 | force_sigsegv(int sig, struct task_struct *p) | |
1508 | { | |
1509 | if (sig == SIGSEGV) { | |
1510 | unsigned long flags; | |
1511 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1512 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1513 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1514 | } | |
1515 | force_sig(SIGSEGV, p); | |
1516 | return 0; | |
1517 | } | |
1518 | ||
c4b92fc1 EB |
1519 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1520 | { | |
146a505d PE |
1521 | int ret; |
1522 | ||
1523 | read_lock(&tasklist_lock); | |
1524 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1525 | read_unlock(&tasklist_lock); | |
1526 | ||
1527 | return ret; | |
c4b92fc1 EB |
1528 | } |
1529 | EXPORT_SYMBOL(kill_pgrp); | |
1530 | ||
1531 | int kill_pid(struct pid *pid, int sig, int priv) | |
1532 | { | |
1533 | return kill_pid_info(sig, __si_special(priv), pid); | |
1534 | } | |
1535 | EXPORT_SYMBOL(kill_pid); | |
1536 | ||
1da177e4 LT |
1537 | /* |
1538 | * These functions support sending signals using preallocated sigqueue | |
1539 | * structures. This is needed "because realtime applications cannot | |
1540 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1541 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1542 | * we allocate the sigqueue structure from the timer_create. If this |
1543 | * allocation fails we are able to report the failure to the application | |
1544 | * with an EAGAIN error. | |
1545 | */ | |
1da177e4 LT |
1546 | struct sigqueue *sigqueue_alloc(void) |
1547 | { | |
f84d49b2 | 1548 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1549 | |
f84d49b2 | 1550 | if (q) |
1da177e4 | 1551 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1552 | |
1553 | return q; | |
1da177e4 LT |
1554 | } |
1555 | ||
1556 | void sigqueue_free(struct sigqueue *q) | |
1557 | { | |
1558 | unsigned long flags; | |
60187d27 ON |
1559 | spinlock_t *lock = ¤t->sighand->siglock; |
1560 | ||
1da177e4 LT |
1561 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1562 | /* | |
c8e85b4f ON |
1563 | * We must hold ->siglock while testing q->list |
1564 | * to serialize with collect_signal() or with | |
da7978b0 | 1565 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1566 | */ |
60187d27 | 1567 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1568 | q->flags &= ~SIGQUEUE_PREALLOC; |
1569 | /* | |
1570 | * If it is queued it will be freed when dequeued, | |
1571 | * like the "regular" sigqueue. | |
1572 | */ | |
60187d27 | 1573 | if (!list_empty(&q->list)) |
c8e85b4f | 1574 | q = NULL; |
60187d27 ON |
1575 | spin_unlock_irqrestore(lock, flags); |
1576 | ||
c8e85b4f ON |
1577 | if (q) |
1578 | __sigqueue_free(q); | |
1da177e4 LT |
1579 | } |
1580 | ||
ac5c2153 | 1581 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1582 | { |
e62e6650 | 1583 | int sig = q->info.si_signo; |
2ca3515a | 1584 | struct sigpending *pending; |
e62e6650 | 1585 | unsigned long flags; |
163566f6 | 1586 | int ret, result; |
2ca3515a | 1587 | |
4cd4b6d4 | 1588 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1589 | |
1590 | ret = -1; | |
1591 | if (!likely(lock_task_sighand(t, &flags))) | |
1592 | goto ret; | |
1593 | ||
7e695a5e | 1594 | ret = 1; /* the signal is ignored */ |
163566f6 | 1595 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1596 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1597 | goto out; |
1598 | ||
1599 | ret = 0; | |
9e3bd6c3 PE |
1600 | if (unlikely(!list_empty(&q->list))) { |
1601 | /* | |
1602 | * If an SI_TIMER entry is already queue just increment | |
1603 | * the overrun count. | |
1604 | */ | |
9e3bd6c3 PE |
1605 | BUG_ON(q->info.si_code != SI_TIMER); |
1606 | q->info.si_overrun++; | |
163566f6 | 1607 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1608 | goto out; |
9e3bd6c3 | 1609 | } |
ba661292 | 1610 | q->info.si_overrun = 0; |
9e3bd6c3 | 1611 | |
9e3bd6c3 | 1612 | signalfd_notify(t, sig); |
2ca3515a | 1613 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1614 | list_add_tail(&q->list, &pending->list); |
1615 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1616 | complete_signal(sig, t, group); |
163566f6 | 1617 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1618 | out: |
163566f6 | 1619 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1620 | unlock_task_sighand(t, &flags); |
1621 | ret: | |
1622 | return ret; | |
9e3bd6c3 PE |
1623 | } |
1624 | ||
1da177e4 LT |
1625 | /* |
1626 | * Let a parent know about the death of a child. | |
1627 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1628 | * |
53c8f9f1 ON |
1629 | * Returns true if our parent ignored us and so we've switched to |
1630 | * self-reaping. | |
1da177e4 | 1631 | */ |
53c8f9f1 | 1632 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1633 | { |
1634 | struct siginfo info; | |
1635 | unsigned long flags; | |
1636 | struct sighand_struct *psig; | |
53c8f9f1 | 1637 | bool autoreap = false; |
1da177e4 LT |
1638 | |
1639 | BUG_ON(sig == -1); | |
1640 | ||
1641 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1642 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1643 | |
d21142ec | 1644 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1645 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1646 | ||
b6e238dc ON |
1647 | if (sig != SIGCHLD) { |
1648 | /* | |
1649 | * This is only possible if parent == real_parent. | |
1650 | * Check if it has changed security domain. | |
1651 | */ | |
1652 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1653 | sig = SIGCHLD; | |
1654 | } | |
1655 | ||
1da177e4 LT |
1656 | info.si_signo = sig; |
1657 | info.si_errno = 0; | |
b488893a | 1658 | /* |
32084504 EB |
1659 | * We are under tasklist_lock here so our parent is tied to |
1660 | * us and cannot change. | |
b488893a | 1661 | * |
32084504 EB |
1662 | * task_active_pid_ns will always return the same pid namespace |
1663 | * until a task passes through release_task. | |
b488893a PE |
1664 | * |
1665 | * write_lock() currently calls preempt_disable() which is the | |
1666 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1667 | * correct to rely on this | |
1668 | */ | |
1669 | rcu_read_lock(); | |
32084504 | 1670 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1671 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1672 | task_uid(tsk)); | |
b488893a PE |
1673 | rcu_read_unlock(); |
1674 | ||
64861634 MS |
1675 | info.si_utime = cputime_to_clock_t(tsk->utime + tsk->signal->utime); |
1676 | info.si_stime = cputime_to_clock_t(tsk->stime + tsk->signal->stime); | |
1da177e4 LT |
1677 | |
1678 | info.si_status = tsk->exit_code & 0x7f; | |
1679 | if (tsk->exit_code & 0x80) | |
1680 | info.si_code = CLD_DUMPED; | |
1681 | else if (tsk->exit_code & 0x7f) | |
1682 | info.si_code = CLD_KILLED; | |
1683 | else { | |
1684 | info.si_code = CLD_EXITED; | |
1685 | info.si_status = tsk->exit_code >> 8; | |
1686 | } | |
1687 | ||
1688 | psig = tsk->parent->sighand; | |
1689 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1690 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1691 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1692 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1693 | /* | |
1694 | * We are exiting and our parent doesn't care. POSIX.1 | |
1695 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1696 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1697 | * automatically and not left for our parent's wait4 call. | |
1698 | * Rather than having the parent do it as a magic kind of | |
1699 | * signal handler, we just set this to tell do_exit that we | |
1700 | * can be cleaned up without becoming a zombie. Note that | |
1701 | * we still call __wake_up_parent in this case, because a | |
1702 | * blocked sys_wait4 might now return -ECHILD. | |
1703 | * | |
1704 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1705 | * is implementation-defined: we do (if you don't want | |
1706 | * it, just use SIG_IGN instead). | |
1707 | */ | |
53c8f9f1 | 1708 | autoreap = true; |
1da177e4 | 1709 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1710 | sig = 0; |
1da177e4 | 1711 | } |
53c8f9f1 | 1712 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1713 | __group_send_sig_info(sig, &info, tsk->parent); |
1714 | __wake_up_parent(tsk, tsk->parent); | |
1715 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1716 | |
53c8f9f1 | 1717 | return autoreap; |
1da177e4 LT |
1718 | } |
1719 | ||
75b95953 TH |
1720 | /** |
1721 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1722 | * @tsk: task reporting the state change | |
1723 | * @for_ptracer: the notification is for ptracer | |
1724 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1725 | * | |
1726 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1727 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1728 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1729 | * | |
1730 | * CONTEXT: | |
1731 | * Must be called with tasklist_lock at least read locked. | |
1732 | */ | |
1733 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1734 | bool for_ptracer, int why) | |
1da177e4 LT |
1735 | { |
1736 | struct siginfo info; | |
1737 | unsigned long flags; | |
bc505a47 | 1738 | struct task_struct *parent; |
1da177e4 LT |
1739 | struct sighand_struct *sighand; |
1740 | ||
75b95953 | 1741 | if (for_ptracer) { |
bc505a47 | 1742 | parent = tsk->parent; |
75b95953 | 1743 | } else { |
bc505a47 ON |
1744 | tsk = tsk->group_leader; |
1745 | parent = tsk->real_parent; | |
1746 | } | |
1747 | ||
1da177e4 LT |
1748 | info.si_signo = SIGCHLD; |
1749 | info.si_errno = 0; | |
b488893a | 1750 | /* |
5aba085e | 1751 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1752 | */ |
1753 | rcu_read_lock(); | |
d9265663 | 1754 | info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns); |
54ba47ed | 1755 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1756 | rcu_read_unlock(); |
1757 | ||
d8878ba3 MK |
1758 | info.si_utime = cputime_to_clock_t(tsk->utime); |
1759 | info.si_stime = cputime_to_clock_t(tsk->stime); | |
1da177e4 LT |
1760 | |
1761 | info.si_code = why; | |
1762 | switch (why) { | |
1763 | case CLD_CONTINUED: | |
1764 | info.si_status = SIGCONT; | |
1765 | break; | |
1766 | case CLD_STOPPED: | |
1767 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1768 | break; | |
1769 | case CLD_TRAPPED: | |
1770 | info.si_status = tsk->exit_code & 0x7f; | |
1771 | break; | |
1772 | default: | |
1773 | BUG(); | |
1774 | } | |
1775 | ||
1776 | sighand = parent->sighand; | |
1777 | spin_lock_irqsave(&sighand->siglock, flags); | |
1778 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1779 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1780 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1781 | /* | |
1782 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1783 | */ | |
1784 | __wake_up_parent(tsk, parent); | |
1785 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1786 | } | |
1787 | ||
d5f70c00 ON |
1788 | static inline int may_ptrace_stop(void) |
1789 | { | |
d21142ec | 1790 | if (!likely(current->ptrace)) |
d5f70c00 | 1791 | return 0; |
d5f70c00 ON |
1792 | /* |
1793 | * Are we in the middle of do_coredump? | |
1794 | * If so and our tracer is also part of the coredump stopping | |
1795 | * is a deadlock situation, and pointless because our tracer | |
1796 | * is dead so don't allow us to stop. | |
1797 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1798 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 ON |
1799 | * is safe to enter schedule(). |
1800 | */ | |
999d9fc1 | 1801 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1802 | unlikely(current->mm == current->parent->mm)) |
1803 | return 0; | |
1804 | ||
1805 | return 1; | |
1806 | } | |
1807 | ||
1a669c2f | 1808 | /* |
5aba085e | 1809 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1810 | * Called with the siglock held. |
1811 | */ | |
1812 | static int sigkill_pending(struct task_struct *tsk) | |
1813 | { | |
3d749b9e ON |
1814 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1815 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1816 | } |
1817 | ||
1da177e4 LT |
1818 | /* |
1819 | * This must be called with current->sighand->siglock held. | |
1820 | * | |
1821 | * This should be the path for all ptrace stops. | |
1822 | * We always set current->last_siginfo while stopped here. | |
1823 | * That makes it a way to test a stopped process for | |
1824 | * being ptrace-stopped vs being job-control-stopped. | |
1825 | * | |
20686a30 ON |
1826 | * If we actually decide not to stop at all because the tracer |
1827 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1828 | */ |
fe1bc6a0 | 1829 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1830 | __releases(¤t->sighand->siglock) |
1831 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1832 | { |
ceb6bd67 TH |
1833 | bool gstop_done = false; |
1834 | ||
1a669c2f RM |
1835 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1836 | /* | |
1837 | * The arch code has something special to do before a | |
1838 | * ptrace stop. This is allowed to block, e.g. for faults | |
1839 | * on user stack pages. We can't keep the siglock while | |
1840 | * calling arch_ptrace_stop, so we must release it now. | |
1841 | * To preserve proper semantics, we must do this before | |
1842 | * any signal bookkeeping like checking group_stop_count. | |
1843 | * Meanwhile, a SIGKILL could come in before we retake the | |
1844 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1845 | * So after regaining the lock, we must check for SIGKILL. | |
1846 | */ | |
1847 | spin_unlock_irq(¤t->sighand->siglock); | |
1848 | arch_ptrace_stop(exit_code, info); | |
1849 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1850 | if (sigkill_pending(current)) |
1851 | return; | |
1a669c2f RM |
1852 | } |
1853 | ||
1da177e4 | 1854 | /* |
81be24b8 TH |
1855 | * We're committing to trapping. TRACED should be visible before |
1856 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1857 | * Also, transition to TRACED and updates to ->jobctl should be | |
1858 | * atomic with respect to siglock and should be done after the arch | |
1859 | * hook as siglock is released and regrabbed across it. | |
1da177e4 | 1860 | */ |
81be24b8 | 1861 | set_current_state(TASK_TRACED); |
1da177e4 LT |
1862 | |
1863 | current->last_siginfo = info; | |
1864 | current->exit_code = exit_code; | |
1865 | ||
d79fdd6d | 1866 | /* |
0ae8ce1c TH |
1867 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1868 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1869 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1870 | * could be clear now. We act as if SIGCONT is received after | |
1871 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1872 | */ |
a8f072c1 | 1873 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1874 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1875 | |
fb1d910c | 1876 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1877 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1878 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1879 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1880 | |
81be24b8 | 1881 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1882 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1883 | |
1da177e4 LT |
1884 | spin_unlock_irq(¤t->sighand->siglock); |
1885 | read_lock(&tasklist_lock); | |
3d749b9e | 1886 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1887 | /* |
1888 | * Notify parents of the stop. | |
1889 | * | |
1890 | * While ptraced, there are two parents - the ptracer and | |
1891 | * the real_parent of the group_leader. The ptracer should | |
1892 | * know about every stop while the real parent is only | |
1893 | * interested in the completion of group stop. The states | |
1894 | * for the two don't interact with each other. Notify | |
1895 | * separately unless they're gonna be duplicates. | |
1896 | */ | |
1897 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1898 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1899 | do_notify_parent_cldstop(current, false, why); |
1900 | ||
53da1d94 MS |
1901 | /* |
1902 | * Don't want to allow preemption here, because | |
1903 | * sys_ptrace() needs this task to be inactive. | |
1904 | * | |
1905 | * XXX: implement read_unlock_no_resched(). | |
1906 | */ | |
1907 | preempt_disable(); | |
1da177e4 | 1908 | read_unlock(&tasklist_lock); |
53da1d94 | 1909 | preempt_enable_no_resched(); |
1da177e4 LT |
1910 | schedule(); |
1911 | } else { | |
1912 | /* | |
1913 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1914 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1915 | * |
1916 | * If @gstop_done, the ptracer went away between group stop | |
1917 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1918 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1919 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1920 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1921 | */ |
ceb6bd67 TH |
1922 | if (gstop_done) |
1923 | do_notify_parent_cldstop(current, false, why); | |
1924 | ||
6405f7f4 | 1925 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1926 | if (clear_code) |
1927 | current->exit_code = 0; | |
6405f7f4 | 1928 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1929 | } |
1930 | ||
13b1c3d4 RM |
1931 | /* |
1932 | * While in TASK_TRACED, we were considered "frozen enough". | |
1933 | * Now that we woke up, it's crucial if we're supposed to be | |
1934 | * frozen that we freeze now before running anything substantial. | |
1935 | */ | |
1936 | try_to_freeze(); | |
1937 | ||
1da177e4 LT |
1938 | /* |
1939 | * We are back. Now reacquire the siglock before touching | |
1940 | * last_siginfo, so that we are sure to have synchronized with | |
1941 | * any signal-sending on another CPU that wants to examine it. | |
1942 | */ | |
1943 | spin_lock_irq(¤t->sighand->siglock); | |
1944 | current->last_siginfo = NULL; | |
1945 | ||
544b2c91 TH |
1946 | /* LISTENING can be set only during STOP traps, clear it */ |
1947 | current->jobctl &= ~JOBCTL_LISTENING; | |
1948 | ||
1da177e4 LT |
1949 | /* |
1950 | * Queued signals ignored us while we were stopped for tracing. | |
1951 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1952 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1953 | */ |
b74d0deb | 1954 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1955 | } |
1956 | ||
3544d72a | 1957 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1958 | { |
1959 | siginfo_t info; | |
1960 | ||
1da177e4 | 1961 | memset(&info, 0, sizeof info); |
3544d72a | 1962 | info.si_signo = signr; |
1da177e4 | 1963 | info.si_code = exit_code; |
b488893a | 1964 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1965 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1966 | |
1967 | /* Let the debugger run. */ | |
3544d72a TH |
1968 | ptrace_stop(exit_code, why, 1, &info); |
1969 | } | |
1970 | ||
1971 | void ptrace_notify(int exit_code) | |
1972 | { | |
1973 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
72667028 AV |
1974 | if (unlikely(current->task_works)) { |
1975 | if (test_and_clear_ti_thread_flag(current_thread_info(), | |
1976 | TIF_NOTIFY_RESUME)) { | |
1977 | smp_mb__after_clear_bit(); | |
1978 | task_work_run(); | |
1979 | } | |
1980 | } | |
3544d72a | 1981 | |
1da177e4 | 1982 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1983 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1984 | spin_unlock_irq(¤t->sighand->siglock); |
1985 | } | |
1986 | ||
73ddff2b TH |
1987 | /** |
1988 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1989 | * @signr: signr causing group stop if initiating | |
1990 | * | |
1991 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1992 | * and participate in it. If already set, participate in the existing | |
1993 | * group stop. If participated in a group stop (and thus slept), %true is | |
1994 | * returned with siglock released. | |
1995 | * | |
1996 | * If ptraced, this function doesn't handle stop itself. Instead, | |
1997 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
1998 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
1999 | * places afterwards. | |
2000 | * | |
2001 | * CONTEXT: | |
2002 | * Must be called with @current->sighand->siglock held, which is released | |
2003 | * on %true return. | |
2004 | * | |
2005 | * RETURNS: | |
2006 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
2007 | * %true if participated in group stop. | |
1da177e4 | 2008 | */ |
73ddff2b TH |
2009 | static bool do_signal_stop(int signr) |
2010 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
2011 | { |
2012 | struct signal_struct *sig = current->signal; | |
1da177e4 | 2013 | |
a8f072c1 TH |
2014 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
2015 | unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; | |
f558b7e4 ON |
2016 | struct task_struct *t; |
2017 | ||
a8f072c1 TH |
2018 | /* signr will be recorded in task->jobctl for retries */ |
2019 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 2020 | |
a8f072c1 | 2021 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 2022 | unlikely(signal_group_exit(sig))) |
73ddff2b | 2023 | return false; |
1da177e4 | 2024 | /* |
408a37de TH |
2025 | * There is no group stop already in progress. We must |
2026 | * initiate one now. | |
2027 | * | |
2028 | * While ptraced, a task may be resumed while group stop is | |
2029 | * still in effect and then receive a stop signal and | |
2030 | * initiate another group stop. This deviates from the | |
2031 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2032 | * cause two group stops when !ptraced. That is why we |
2033 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2034 | * |
2035 | * The condition can be distinguished by testing whether | |
2036 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2037 | * group_exit_code in such case. | |
2038 | * | |
2039 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2040 | * an intervening stop signal is required to cause two | |
2041 | * continued events regardless of ptrace. | |
1da177e4 | 2042 | */ |
408a37de TH |
2043 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2044 | sig->group_exit_code = signr; | |
1da177e4 | 2045 | |
7dd3db54 TH |
2046 | sig->group_stop_count = 0; |
2047 | ||
2048 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2049 | sig->group_stop_count++; | |
1da177e4 | 2050 | |
d79fdd6d TH |
2051 | for (t = next_thread(current); t != current; |
2052 | t = next_thread(t)) { | |
1da177e4 | 2053 | /* |
a122b341 ON |
2054 | * Setting state to TASK_STOPPED for a group |
2055 | * stop is always done with the siglock held, | |
2056 | * so this check has no races. | |
1da177e4 | 2057 | */ |
7dd3db54 TH |
2058 | if (!task_is_stopped(t) && |
2059 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2060 | sig->group_stop_count++; |
fb1d910c TH |
2061 | if (likely(!(t->ptrace & PT_SEIZED))) |
2062 | signal_wake_up(t, 0); | |
2063 | else | |
2064 | ptrace_trap_notify(t); | |
a122b341 | 2065 | } |
d79fdd6d | 2066 | } |
1da177e4 | 2067 | } |
73ddff2b | 2068 | |
d21142ec | 2069 | if (likely(!current->ptrace)) { |
5224fa36 | 2070 | int notify = 0; |
1da177e4 | 2071 | |
5224fa36 TH |
2072 | /* |
2073 | * If there are no other threads in the group, or if there | |
2074 | * is a group stop in progress and we are the last to stop, | |
2075 | * report to the parent. | |
2076 | */ | |
2077 | if (task_participate_group_stop(current)) | |
2078 | notify = CLD_STOPPED; | |
2079 | ||
ae6d2ed7 | 2080 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
2081 | spin_unlock_irq(¤t->sighand->siglock); |
2082 | ||
62bcf9d9 TH |
2083 | /* |
2084 | * Notify the parent of the group stop completion. Because | |
2085 | * we're not holding either the siglock or tasklist_lock | |
2086 | * here, ptracer may attach inbetween; however, this is for | |
2087 | * group stop and should always be delivered to the real | |
2088 | * parent of the group leader. The new ptracer will get | |
2089 | * its notification when this task transitions into | |
2090 | * TASK_TRACED. | |
2091 | */ | |
5224fa36 TH |
2092 | if (notify) { |
2093 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2094 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2095 | read_unlock(&tasklist_lock); |
2096 | } | |
2097 | ||
2098 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
2099 | schedule(); | |
73ddff2b | 2100 | return true; |
d79fdd6d | 2101 | } else { |
73ddff2b TH |
2102 | /* |
2103 | * While ptraced, group stop is handled by STOP trap. | |
2104 | * Schedule it and let the caller deal with it. | |
2105 | */ | |
2106 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2107 | return false; | |
ae6d2ed7 | 2108 | } |
73ddff2b | 2109 | } |
1da177e4 | 2110 | |
73ddff2b TH |
2111 | /** |
2112 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2113 | * | |
3544d72a TH |
2114 | * When PT_SEIZED, it's used for both group stop and explicit |
2115 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2116 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2117 | * the stop signal; otherwise, %SIGTRAP. | |
2118 | * | |
2119 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2120 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2121 | * |
2122 | * CONTEXT: | |
2123 | * Must be called with @current->sighand->siglock held, which may be | |
2124 | * released and re-acquired before returning with intervening sleep. | |
2125 | */ | |
2126 | static void do_jobctl_trap(void) | |
2127 | { | |
3544d72a | 2128 | struct signal_struct *signal = current->signal; |
73ddff2b | 2129 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2130 | |
3544d72a TH |
2131 | if (current->ptrace & PT_SEIZED) { |
2132 | if (!signal->group_stop_count && | |
2133 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2134 | signr = SIGTRAP; | |
2135 | WARN_ON_ONCE(!signr); | |
2136 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2137 | CLD_STOPPED); | |
2138 | } else { | |
2139 | WARN_ON_ONCE(!signr); | |
2140 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2141 | current->exit_code = 0; | |
ae6d2ed7 | 2142 | } |
1da177e4 LT |
2143 | } |
2144 | ||
18c98b65 RM |
2145 | static int ptrace_signal(int signr, siginfo_t *info, |
2146 | struct pt_regs *regs, void *cookie) | |
2147 | { | |
18c98b65 | 2148 | ptrace_signal_deliver(regs, cookie); |
8a352418 ON |
2149 | /* |
2150 | * We do not check sig_kernel_stop(signr) but set this marker | |
2151 | * unconditionally because we do not know whether debugger will | |
2152 | * change signr. This flag has no meaning unless we are going | |
2153 | * to stop after return from ptrace_stop(). In this case it will | |
2154 | * be checked in do_signal_stop(), we should only stop if it was | |
2155 | * not cleared by SIGCONT while we were sleeping. See also the | |
2156 | * comment in dequeue_signal(). | |
2157 | */ | |
2158 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2159 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2160 | |
2161 | /* We're back. Did the debugger cancel the sig? */ | |
2162 | signr = current->exit_code; | |
2163 | if (signr == 0) | |
2164 | return signr; | |
2165 | ||
2166 | current->exit_code = 0; | |
2167 | ||
5aba085e RD |
2168 | /* |
2169 | * Update the siginfo structure if the signal has | |
2170 | * changed. If the debugger wanted something | |
2171 | * specific in the siginfo structure then it should | |
2172 | * have updated *info via PTRACE_SETSIGINFO. | |
2173 | */ | |
18c98b65 RM |
2174 | if (signr != info->si_signo) { |
2175 | info->si_signo = signr; | |
2176 | info->si_errno = 0; | |
2177 | info->si_code = SI_USER; | |
6b550f94 | 2178 | rcu_read_lock(); |
18c98b65 | 2179 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2180 | info->si_uid = from_kuid_munged(current_user_ns(), |
2181 | task_uid(current->parent)); | |
6b550f94 | 2182 | rcu_read_unlock(); |
18c98b65 RM |
2183 | } |
2184 | ||
2185 | /* If the (new) signal is now blocked, requeue it. */ | |
2186 | if (sigismember(¤t->blocked, signr)) { | |
2187 | specific_send_sig_info(signr, info, current); | |
2188 | signr = 0; | |
2189 | } | |
2190 | ||
2191 | return signr; | |
2192 | } | |
2193 | ||
1da177e4 LT |
2194 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
2195 | struct pt_regs *regs, void *cookie) | |
2196 | { | |
f6b76d4f ON |
2197 | struct sighand_struct *sighand = current->sighand; |
2198 | struct signal_struct *signal = current->signal; | |
2199 | int signr; | |
1da177e4 | 2200 | |
72667028 AV |
2201 | if (unlikely(current->task_works)) { |
2202 | if (test_and_clear_ti_thread_flag(current_thread_info(), | |
2203 | TIF_NOTIFY_RESUME)) { | |
2204 | smp_mb__after_clear_bit(); | |
2205 | task_work_run(); | |
2206 | } | |
2207 | } | |
2208 | ||
0326f5a9 SD |
2209 | if (unlikely(uprobe_deny_signal())) |
2210 | return 0; | |
2211 | ||
13b1c3d4 RM |
2212 | relock: |
2213 | /* | |
2214 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
2215 | * While in TASK_STOPPED, we were considered "frozen enough". | |
2216 | * Now that we woke up, it's crucial if we're supposed to be | |
2217 | * frozen that we freeze now before running anything substantial. | |
2218 | */ | |
fc558a74 RW |
2219 | try_to_freeze(); |
2220 | ||
f6b76d4f | 2221 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2222 | /* |
2223 | * Every stopped thread goes here after wakeup. Check to see if | |
2224 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2225 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2226 | */ | |
f6b76d4f | 2227 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2228 | int why; |
2229 | ||
2230 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2231 | why = CLD_CONTINUED; | |
2232 | else | |
2233 | why = CLD_STOPPED; | |
2234 | ||
f6b76d4f | 2235 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2236 | |
ae6d2ed7 | 2237 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2238 | |
ceb6bd67 TH |
2239 | /* |
2240 | * Notify the parent that we're continuing. This event is | |
2241 | * always per-process and doesn't make whole lot of sense | |
2242 | * for ptracers, who shouldn't consume the state via | |
2243 | * wait(2) either, but, for backward compatibility, notify | |
2244 | * the ptracer of the group leader too unless it's gonna be | |
2245 | * a duplicate. | |
2246 | */ | |
edf2ed15 | 2247 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2248 | do_notify_parent_cldstop(current, false, why); |
2249 | ||
bb3696da ON |
2250 | if (ptrace_reparented(current->group_leader)) |
2251 | do_notify_parent_cldstop(current->group_leader, | |
2252 | true, why); | |
edf2ed15 | 2253 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2254 | |
e4420551 ON |
2255 | goto relock; |
2256 | } | |
2257 | ||
1da177e4 LT |
2258 | for (;;) { |
2259 | struct k_sigaction *ka; | |
1be53963 | 2260 | |
dd1d6772 TH |
2261 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2262 | do_signal_stop(0)) | |
7bcf6a2c | 2263 | goto relock; |
1be53963 | 2264 | |
73ddff2b TH |
2265 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2266 | do_jobctl_trap(); | |
2267 | spin_unlock_irq(&sighand->siglock); | |
2268 | goto relock; | |
2269 | } | |
1da177e4 | 2270 | |
dd1d6772 | 2271 | signr = dequeue_signal(current, ¤t->blocked, info); |
7bcf6a2c | 2272 | |
dd1d6772 TH |
2273 | if (!signr) |
2274 | break; /* will return 0 */ | |
7bcf6a2c | 2275 | |
8a352418 | 2276 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
dd1d6772 TH |
2277 | signr = ptrace_signal(signr, info, |
2278 | regs, cookie); | |
2279 | if (!signr) | |
2280 | continue; | |
1da177e4 LT |
2281 | } |
2282 | ||
dd1d6772 TH |
2283 | ka = &sighand->action[signr-1]; |
2284 | ||
f9d4257e MH |
2285 | /* Trace actually delivered signals. */ |
2286 | trace_signal_deliver(signr, info, ka); | |
2287 | ||
1da177e4 LT |
2288 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2289 | continue; | |
2290 | if (ka->sa.sa_handler != SIG_DFL) { | |
2291 | /* Run the handler. */ | |
2292 | *return_ka = *ka; | |
2293 | ||
2294 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2295 | ka->sa.sa_handler = SIG_DFL; | |
2296 | ||
2297 | break; /* will return non-zero "signr" value */ | |
2298 | } | |
2299 | ||
2300 | /* | |
2301 | * Now we are doing the default action for this signal. | |
2302 | */ | |
2303 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2304 | continue; | |
2305 | ||
84d73786 | 2306 | /* |
0fbc26a6 | 2307 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2308 | * Container-init gets no signals it doesn't want from same |
2309 | * container. | |
2310 | * | |
2311 | * Note that if global/container-init sees a sig_kernel_only() | |
2312 | * signal here, the signal must have been generated internally | |
2313 | * or must have come from an ancestor namespace. In either | |
2314 | * case, the signal cannot be dropped. | |
84d73786 | 2315 | */ |
fae5fa44 | 2316 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2317 | !sig_kernel_only(signr)) |
1da177e4 LT |
2318 | continue; |
2319 | ||
2320 | if (sig_kernel_stop(signr)) { | |
2321 | /* | |
2322 | * The default action is to stop all threads in | |
2323 | * the thread group. The job control signals | |
2324 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2325 | * always works. Note that siglock needs to be | |
2326 | * dropped during the call to is_orphaned_pgrp() | |
2327 | * because of lock ordering with tasklist_lock. | |
2328 | * This allows an intervening SIGCONT to be posted. | |
2329 | * We need to check for that and bail out if necessary. | |
2330 | */ | |
2331 | if (signr != SIGSTOP) { | |
f6b76d4f | 2332 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2333 | |
2334 | /* signals can be posted during this window */ | |
2335 | ||
3e7cd6c4 | 2336 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2337 | goto relock; |
2338 | ||
f6b76d4f | 2339 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2340 | } |
2341 | ||
7bcf6a2c | 2342 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
2343 | /* It released the siglock. */ |
2344 | goto relock; | |
2345 | } | |
2346 | ||
2347 | /* | |
2348 | * We didn't actually stop, due to a race | |
2349 | * with SIGCONT or something like that. | |
2350 | */ | |
2351 | continue; | |
2352 | } | |
2353 | ||
f6b76d4f | 2354 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2355 | |
2356 | /* | |
2357 | * Anything else is fatal, maybe with a core dump. | |
2358 | */ | |
2359 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2360 | |
1da177e4 | 2361 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2362 | if (print_fatal_signals) |
7bcf6a2c | 2363 | print_fatal_signal(regs, info->si_signo); |
1da177e4 LT |
2364 | /* |
2365 | * If it was able to dump core, this kills all | |
2366 | * other threads in the group and synchronizes with | |
2367 | * their demise. If we lost the race with another | |
2368 | * thread getting here, it set group_exit_code | |
2369 | * first and our do_group_exit call below will use | |
2370 | * that value and ignore the one we pass it. | |
2371 | */ | |
7bcf6a2c | 2372 | do_coredump(info->si_signo, info->si_signo, regs); |
1da177e4 LT |
2373 | } |
2374 | ||
2375 | /* | |
2376 | * Death signals, no core dump. | |
2377 | */ | |
7bcf6a2c | 2378 | do_group_exit(info->si_signo); |
1da177e4 LT |
2379 | /* NOTREACHED */ |
2380 | } | |
f6b76d4f | 2381 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2382 | return signr; |
2383 | } | |
2384 | ||
5e6292c0 | 2385 | /** |
efee984c AV |
2386 | * signal_delivered - |
2387 | * @sig: number of signal being delivered | |
2388 | * @info: siginfo_t of signal being delivered | |
2389 | * @ka: sigaction setting that chose the handler | |
2390 | * @regs: user register state | |
2391 | * @stepping: nonzero if debugger single-step or block-step in use | |
5e6292c0 MF |
2392 | * |
2393 | * This function should be called when a signal has succesfully been | |
efee984c AV |
2394 | * delivered. It updates the blocked signals accordingly (@ka->sa.sa_mask |
2395 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER | |
2396 | * is set in @ka->sa.sa_flags. Tracing is notified. | |
5e6292c0 | 2397 | */ |
efee984c AV |
2398 | void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka, |
2399 | struct pt_regs *regs, int stepping) | |
5e6292c0 MF |
2400 | { |
2401 | sigset_t blocked; | |
2402 | ||
a610d6e6 AV |
2403 | /* A signal was successfully delivered, and the |
2404 | saved sigmask was stored on the signal frame, | |
2405 | and will be restored by sigreturn. So we can | |
2406 | simply clear the restore sigmask flag. */ | |
2407 | clear_restore_sigmask(); | |
2408 | ||
5e6292c0 MF |
2409 | sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask); |
2410 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
efee984c | 2411 | sigaddset(&blocked, sig); |
5e6292c0 | 2412 | set_current_blocked(&blocked); |
efee984c | 2413 | tracehook_signal_handler(sig, info, ka, regs, stepping); |
5e6292c0 MF |
2414 | } |
2415 | ||
0edceb7b ON |
2416 | /* |
2417 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2418 | * group-wide signal. Other threads should be notified now to take |
2419 | * the shared signals in @which since we will not. | |
0edceb7b | 2420 | */ |
f646e227 | 2421 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2422 | { |
f646e227 | 2423 | sigset_t retarget; |
0edceb7b ON |
2424 | struct task_struct *t; |
2425 | ||
f646e227 ON |
2426 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2427 | if (sigisemptyset(&retarget)) | |
2428 | return; | |
2429 | ||
0edceb7b ON |
2430 | t = tsk; |
2431 | while_each_thread(tsk, t) { | |
fec9993d ON |
2432 | if (t->flags & PF_EXITING) |
2433 | continue; | |
2434 | ||
2435 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2436 | continue; | |
2437 | /* Remove the signals this thread can handle. */ | |
2438 | sigandsets(&retarget, &retarget, &t->blocked); | |
2439 | ||
2440 | if (!signal_pending(t)) | |
2441 | signal_wake_up(t, 0); | |
2442 | ||
2443 | if (sigisemptyset(&retarget)) | |
2444 | break; | |
0edceb7b ON |
2445 | } |
2446 | } | |
2447 | ||
d12619b5 ON |
2448 | void exit_signals(struct task_struct *tsk) |
2449 | { | |
2450 | int group_stop = 0; | |
f646e227 | 2451 | sigset_t unblocked; |
d12619b5 | 2452 | |
77e4ef99 TH |
2453 | /* |
2454 | * @tsk is about to have PF_EXITING set - lock out users which | |
2455 | * expect stable threadgroup. | |
2456 | */ | |
2457 | threadgroup_change_begin(tsk); | |
2458 | ||
5dee1707 ON |
2459 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2460 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2461 | threadgroup_change_end(tsk); |
5dee1707 | 2462 | return; |
d12619b5 ON |
2463 | } |
2464 | ||
5dee1707 | 2465 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2466 | /* |
2467 | * From now this task is not visible for group-wide signals, | |
2468 | * see wants_signal(), do_signal_stop(). | |
2469 | */ | |
2470 | tsk->flags |= PF_EXITING; | |
77e4ef99 TH |
2471 | |
2472 | threadgroup_change_end(tsk); | |
2473 | ||
5dee1707 ON |
2474 | if (!signal_pending(tsk)) |
2475 | goto out; | |
2476 | ||
f646e227 ON |
2477 | unblocked = tsk->blocked; |
2478 | signotset(&unblocked); | |
2479 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2480 | |
a8f072c1 | 2481 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2482 | task_participate_group_stop(tsk)) |
edf2ed15 | 2483 | group_stop = CLD_STOPPED; |
5dee1707 | 2484 | out: |
d12619b5 ON |
2485 | spin_unlock_irq(&tsk->sighand->siglock); |
2486 | ||
62bcf9d9 TH |
2487 | /* |
2488 | * If group stop has completed, deliver the notification. This | |
2489 | * should always go to the real parent of the group leader. | |
2490 | */ | |
ae6d2ed7 | 2491 | if (unlikely(group_stop)) { |
d12619b5 | 2492 | read_lock(&tasklist_lock); |
62bcf9d9 | 2493 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2494 | read_unlock(&tasklist_lock); |
2495 | } | |
2496 | } | |
2497 | ||
1da177e4 LT |
2498 | EXPORT_SYMBOL(recalc_sigpending); |
2499 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2500 | EXPORT_SYMBOL(flush_signals); | |
2501 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2502 | EXPORT_SYMBOL(send_sig); |
2503 | EXPORT_SYMBOL(send_sig_info); | |
2504 | EXPORT_SYMBOL(sigprocmask); | |
2505 | EXPORT_SYMBOL(block_all_signals); | |
2506 | EXPORT_SYMBOL(unblock_all_signals); | |
2507 | ||
2508 | ||
2509 | /* | |
2510 | * System call entry points. | |
2511 | */ | |
2512 | ||
41c57892 RD |
2513 | /** |
2514 | * sys_restart_syscall - restart a system call | |
2515 | */ | |
754fe8d2 | 2516 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2517 | { |
2518 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2519 | return restart->fn(restart); | |
2520 | } | |
2521 | ||
2522 | long do_no_restart_syscall(struct restart_block *param) | |
2523 | { | |
2524 | return -EINTR; | |
2525 | } | |
2526 | ||
b182801a ON |
2527 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2528 | { | |
2529 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2530 | sigset_t newblocked; | |
2531 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2532 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2533 | retarget_shared_pending(tsk, &newblocked); |
2534 | } | |
2535 | tsk->blocked = *newset; | |
2536 | recalc_sigpending(); | |
2537 | } | |
2538 | ||
e6fa16ab ON |
2539 | /** |
2540 | * set_current_blocked - change current->blocked mask | |
2541 | * @newset: new mask | |
2542 | * | |
2543 | * It is wrong to change ->blocked directly, this helper should be used | |
2544 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2545 | */ |
77097ae5 AV |
2546 | void set_current_blocked(sigset_t *newset) |
2547 | { | |
2548 | struct task_struct *tsk = current; | |
2549 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2550 | spin_lock_irq(&tsk->sighand->siglock); | |
2551 | __set_task_blocked(tsk, newset); | |
2552 | spin_unlock_irq(&tsk->sighand->siglock); | |
2553 | } | |
2554 | ||
2555 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2556 | { |
2557 | struct task_struct *tsk = current; | |
2558 | ||
2559 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2560 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2561 | spin_unlock_irq(&tsk->sighand->siglock); |
2562 | } | |
1da177e4 LT |
2563 | |
2564 | /* | |
2565 | * This is also useful for kernel threads that want to temporarily | |
2566 | * (or permanently) block certain signals. | |
2567 | * | |
2568 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2569 | * interface happily blocks "unblockable" signals like SIGKILL | |
2570 | * and friends. | |
2571 | */ | |
2572 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2573 | { | |
73ef4aeb ON |
2574 | struct task_struct *tsk = current; |
2575 | sigset_t newset; | |
1da177e4 | 2576 | |
73ef4aeb | 2577 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2578 | if (oldset) |
73ef4aeb | 2579 | *oldset = tsk->blocked; |
a26fd335 | 2580 | |
1da177e4 LT |
2581 | switch (how) { |
2582 | case SIG_BLOCK: | |
73ef4aeb | 2583 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2584 | break; |
2585 | case SIG_UNBLOCK: | |
702a5073 | 2586 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2587 | break; |
2588 | case SIG_SETMASK: | |
73ef4aeb | 2589 | newset = *set; |
1da177e4 LT |
2590 | break; |
2591 | default: | |
73ef4aeb | 2592 | return -EINVAL; |
1da177e4 | 2593 | } |
a26fd335 | 2594 | |
77097ae5 | 2595 | __set_current_blocked(&newset); |
73ef4aeb | 2596 | return 0; |
1da177e4 LT |
2597 | } |
2598 | ||
41c57892 RD |
2599 | /** |
2600 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2601 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2602 | * @nset: stores pending signals |
41c57892 RD |
2603 | * @oset: previous value of signal mask if non-null |
2604 | * @sigsetsize: size of sigset_t type | |
2605 | */ | |
bb7efee2 | 2606 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2607 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2608 | { |
1da177e4 | 2609 | sigset_t old_set, new_set; |
bb7efee2 | 2610 | int error; |
1da177e4 LT |
2611 | |
2612 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2613 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2614 | return -EINVAL; |
1da177e4 | 2615 | |
bb7efee2 ON |
2616 | old_set = current->blocked; |
2617 | ||
2618 | if (nset) { | |
2619 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2620 | return -EFAULT; | |
1da177e4 LT |
2621 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2622 | ||
bb7efee2 | 2623 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2624 | if (error) |
bb7efee2 ON |
2625 | return error; |
2626 | } | |
1da177e4 | 2627 | |
bb7efee2 ON |
2628 | if (oset) { |
2629 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2630 | return -EFAULT; | |
1da177e4 | 2631 | } |
bb7efee2 ON |
2632 | |
2633 | return 0; | |
1da177e4 LT |
2634 | } |
2635 | ||
2636 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2637 | { | |
2638 | long error = -EINVAL; | |
2639 | sigset_t pending; | |
2640 | ||
2641 | if (sigsetsize > sizeof(sigset_t)) | |
2642 | goto out; | |
2643 | ||
2644 | spin_lock_irq(¤t->sighand->siglock); | |
2645 | sigorsets(&pending, ¤t->pending.signal, | |
2646 | ¤t->signal->shared_pending.signal); | |
2647 | spin_unlock_irq(¤t->sighand->siglock); | |
2648 | ||
2649 | /* Outside the lock because only this thread touches it. */ | |
2650 | sigandsets(&pending, ¤t->blocked, &pending); | |
2651 | ||
2652 | error = -EFAULT; | |
2653 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2654 | error = 0; | |
2655 | ||
2656 | out: | |
2657 | return error; | |
5aba085e | 2658 | } |
1da177e4 | 2659 | |
41c57892 RD |
2660 | /** |
2661 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2662 | * while blocked | |
2663 | * @set: stores pending signals | |
2664 | * @sigsetsize: size of sigset_t type or larger | |
2665 | */ | |
17da2bd9 | 2666 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize) |
1da177e4 LT |
2667 | { |
2668 | return do_sigpending(set, sigsetsize); | |
2669 | } | |
2670 | ||
2671 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2672 | ||
2673 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2674 | { | |
2675 | int err; | |
2676 | ||
2677 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2678 | return -EFAULT; | |
2679 | if (from->si_code < 0) | |
2680 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2681 | ? -EFAULT : 0; | |
2682 | /* | |
2683 | * If you change siginfo_t structure, please be sure | |
2684 | * this code is fixed accordingly. | |
fba2afaa DL |
2685 | * Please remember to update the signalfd_copyinfo() function |
2686 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2687 | * It should never copy any pad contained in the structure |
2688 | * to avoid security leaks, but must copy the generic | |
2689 | * 3 ints plus the relevant union member. | |
2690 | */ | |
2691 | err = __put_user(from->si_signo, &to->si_signo); | |
2692 | err |= __put_user(from->si_errno, &to->si_errno); | |
2693 | err |= __put_user((short)from->si_code, &to->si_code); | |
2694 | switch (from->si_code & __SI_MASK) { | |
2695 | case __SI_KILL: | |
2696 | err |= __put_user(from->si_pid, &to->si_pid); | |
2697 | err |= __put_user(from->si_uid, &to->si_uid); | |
2698 | break; | |
2699 | case __SI_TIMER: | |
2700 | err |= __put_user(from->si_tid, &to->si_tid); | |
2701 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2702 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2703 | break; | |
2704 | case __SI_POLL: | |
2705 | err |= __put_user(from->si_band, &to->si_band); | |
2706 | err |= __put_user(from->si_fd, &to->si_fd); | |
2707 | break; | |
2708 | case __SI_FAULT: | |
2709 | err |= __put_user(from->si_addr, &to->si_addr); | |
2710 | #ifdef __ARCH_SI_TRAPNO | |
2711 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2712 | #endif |
2713 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2714 | /* |
a337fdac | 2715 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2716 | * so check explicitly for the right codes here. |
a337fdac AK |
2717 | */ |
2718 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2719 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2720 | #endif |
2721 | break; | |
2722 | case __SI_CHLD: | |
2723 | err |= __put_user(from->si_pid, &to->si_pid); | |
2724 | err |= __put_user(from->si_uid, &to->si_uid); | |
2725 | err |= __put_user(from->si_status, &to->si_status); | |
2726 | err |= __put_user(from->si_utime, &to->si_utime); | |
2727 | err |= __put_user(from->si_stime, &to->si_stime); | |
2728 | break; | |
2729 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2730 | case __SI_MESGQ: /* But this is */ | |
2731 | err |= __put_user(from->si_pid, &to->si_pid); | |
2732 | err |= __put_user(from->si_uid, &to->si_uid); | |
2733 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2734 | break; | |
a0727e8c WD |
2735 | #ifdef __ARCH_SIGSYS |
2736 | case __SI_SYS: | |
2737 | err |= __put_user(from->si_call_addr, &to->si_call_addr); | |
2738 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2739 | err |= __put_user(from->si_arch, &to->si_arch); | |
2740 | break; | |
2741 | #endif | |
1da177e4 LT |
2742 | default: /* this is just in case for now ... */ |
2743 | err |= __put_user(from->si_pid, &to->si_pid); | |
2744 | err |= __put_user(from->si_uid, &to->si_uid); | |
2745 | break; | |
2746 | } | |
2747 | return err; | |
2748 | } | |
2749 | ||
2750 | #endif | |
2751 | ||
943df148 ON |
2752 | /** |
2753 | * do_sigtimedwait - wait for queued signals specified in @which | |
2754 | * @which: queued signals to wait for | |
2755 | * @info: if non-null, the signal's siginfo is returned here | |
2756 | * @ts: upper bound on process time suspension | |
2757 | */ | |
2758 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info, | |
2759 | const struct timespec *ts) | |
2760 | { | |
2761 | struct task_struct *tsk = current; | |
2762 | long timeout = MAX_SCHEDULE_TIMEOUT; | |
2763 | sigset_t mask = *which; | |
2764 | int sig; | |
2765 | ||
2766 | if (ts) { | |
2767 | if (!timespec_valid(ts)) | |
2768 | return -EINVAL; | |
2769 | timeout = timespec_to_jiffies(ts); | |
2770 | /* | |
2771 | * We can be close to the next tick, add another one | |
2772 | * to ensure we will wait at least the time asked for. | |
2773 | */ | |
2774 | if (ts->tv_sec || ts->tv_nsec) | |
2775 | timeout++; | |
2776 | } | |
2777 | ||
2778 | /* | |
2779 | * Invert the set of allowed signals to get those we want to block. | |
2780 | */ | |
2781 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2782 | signotset(&mask); | |
2783 | ||
2784 | spin_lock_irq(&tsk->sighand->siglock); | |
2785 | sig = dequeue_signal(tsk, &mask, info); | |
2786 | if (!sig && timeout) { | |
2787 | /* | |
2788 | * None ready, temporarily unblock those we're interested | |
2789 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2790 | * they arrive. Unblocking is always fine, we can avoid |
2791 | * set_current_blocked(). | |
943df148 ON |
2792 | */ |
2793 | tsk->real_blocked = tsk->blocked; | |
2794 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2795 | recalc_sigpending(); | |
2796 | spin_unlock_irq(&tsk->sighand->siglock); | |
2797 | ||
2798 | timeout = schedule_timeout_interruptible(timeout); | |
2799 | ||
2800 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2801 | __set_task_blocked(tsk, &tsk->real_blocked); |
943df148 | 2802 | siginitset(&tsk->real_blocked, 0); |
b182801a | 2803 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2804 | } |
2805 | spin_unlock_irq(&tsk->sighand->siglock); | |
2806 | ||
2807 | if (sig) | |
2808 | return sig; | |
2809 | return timeout ? -EINTR : -EAGAIN; | |
2810 | } | |
2811 | ||
41c57892 RD |
2812 | /** |
2813 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2814 | * in @uthese | |
2815 | * @uthese: queued signals to wait for | |
2816 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2817 | * @uts: upper bound on process time suspension | |
2818 | * @sigsetsize: size of sigset_t type | |
2819 | */ | |
17da2bd9 HC |
2820 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2821 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2822 | size_t, sigsetsize) | |
1da177e4 | 2823 | { |
1da177e4 LT |
2824 | sigset_t these; |
2825 | struct timespec ts; | |
2826 | siginfo_t info; | |
943df148 | 2827 | int ret; |
1da177e4 LT |
2828 | |
2829 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2830 | if (sigsetsize != sizeof(sigset_t)) | |
2831 | return -EINVAL; | |
2832 | ||
2833 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2834 | return -EFAULT; | |
5aba085e | 2835 | |
1da177e4 LT |
2836 | if (uts) { |
2837 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2838 | return -EFAULT; | |
1da177e4 LT |
2839 | } |
2840 | ||
943df148 | 2841 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2842 | |
943df148 ON |
2843 | if (ret > 0 && uinfo) { |
2844 | if (copy_siginfo_to_user(uinfo, &info)) | |
2845 | ret = -EFAULT; | |
1da177e4 LT |
2846 | } |
2847 | ||
2848 | return ret; | |
2849 | } | |
2850 | ||
41c57892 RD |
2851 | /** |
2852 | * sys_kill - send a signal to a process | |
2853 | * @pid: the PID of the process | |
2854 | * @sig: signal to be sent | |
2855 | */ | |
17da2bd9 | 2856 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2857 | { |
2858 | struct siginfo info; | |
2859 | ||
2860 | info.si_signo = sig; | |
2861 | info.si_errno = 0; | |
2862 | info.si_code = SI_USER; | |
b488893a | 2863 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2864 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2865 | |
2866 | return kill_something_info(sig, &info, pid); | |
2867 | } | |
2868 | ||
30b4ae8a TG |
2869 | static int |
2870 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2871 | { |
1da177e4 | 2872 | struct task_struct *p; |
30b4ae8a | 2873 | int error = -ESRCH; |
1da177e4 | 2874 | |
3547ff3a | 2875 | rcu_read_lock(); |
228ebcbe | 2876 | p = find_task_by_vpid(pid); |
b488893a | 2877 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2878 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2879 | /* |
2880 | * The null signal is a permissions and process existence | |
2881 | * probe. No signal is actually delivered. | |
2882 | */ | |
4a30debf ON |
2883 | if (!error && sig) { |
2884 | error = do_send_sig_info(sig, info, p, false); | |
2885 | /* | |
2886 | * If lock_task_sighand() failed we pretend the task | |
2887 | * dies after receiving the signal. The window is tiny, | |
2888 | * and the signal is private anyway. | |
2889 | */ | |
2890 | if (unlikely(error == -ESRCH)) | |
2891 | error = 0; | |
1da177e4 LT |
2892 | } |
2893 | } | |
3547ff3a | 2894 | rcu_read_unlock(); |
6dd69f10 | 2895 | |
1da177e4 LT |
2896 | return error; |
2897 | } | |
2898 | ||
30b4ae8a TG |
2899 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2900 | { | |
2901 | struct siginfo info; | |
2902 | ||
2903 | info.si_signo = sig; | |
2904 | info.si_errno = 0; | |
2905 | info.si_code = SI_TKILL; | |
2906 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 2907 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
2908 | |
2909 | return do_send_specific(tgid, pid, sig, &info); | |
2910 | } | |
2911 | ||
6dd69f10 VL |
2912 | /** |
2913 | * sys_tgkill - send signal to one specific thread | |
2914 | * @tgid: the thread group ID of the thread | |
2915 | * @pid: the PID of the thread | |
2916 | * @sig: signal to be sent | |
2917 | * | |
72fd4a35 | 2918 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2919 | * exists but it's not belonging to the target process anymore. This |
2920 | * method solves the problem of threads exiting and PIDs getting reused. | |
2921 | */ | |
a5f8fa9e | 2922 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2923 | { |
2924 | /* This is only valid for single tasks */ | |
2925 | if (pid <= 0 || tgid <= 0) | |
2926 | return -EINVAL; | |
2927 | ||
2928 | return do_tkill(tgid, pid, sig); | |
2929 | } | |
2930 | ||
41c57892 RD |
2931 | /** |
2932 | * sys_tkill - send signal to one specific task | |
2933 | * @pid: the PID of the task | |
2934 | * @sig: signal to be sent | |
2935 | * | |
1da177e4 LT |
2936 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2937 | */ | |
a5f8fa9e | 2938 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2939 | { |
1da177e4 LT |
2940 | /* This is only valid for single tasks */ |
2941 | if (pid <= 0) | |
2942 | return -EINVAL; | |
2943 | ||
6dd69f10 | 2944 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2945 | } |
2946 | ||
41c57892 RD |
2947 | /** |
2948 | * sys_rt_sigqueueinfo - send signal information to a signal | |
2949 | * @pid: the PID of the thread | |
2950 | * @sig: signal to be sent | |
2951 | * @uinfo: signal info to be sent | |
2952 | */ | |
a5f8fa9e HC |
2953 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2954 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2955 | { |
2956 | siginfo_t info; | |
2957 | ||
2958 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2959 | return -EFAULT; | |
2960 | ||
2961 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2962 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2963 | */ | |
243b422a | 2964 | if (info.si_code >= 0 || info.si_code == SI_TKILL) { |
da48524e JT |
2965 | /* We used to allow any < 0 si_code */ |
2966 | WARN_ON_ONCE(info.si_code < 0); | |
1da177e4 | 2967 | return -EPERM; |
da48524e | 2968 | } |
1da177e4 LT |
2969 | info.si_signo = sig; |
2970 | ||
2971 | /* POSIX.1b doesn't mention process groups. */ | |
2972 | return kill_proc_info(sig, &info, pid); | |
2973 | } | |
2974 | ||
62ab4505 TG |
2975 | long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
2976 | { | |
2977 | /* This is only valid for single tasks */ | |
2978 | if (pid <= 0 || tgid <= 0) | |
2979 | return -EINVAL; | |
2980 | ||
2981 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
2982 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
2983 | */ | |
243b422a | 2984 | if (info->si_code >= 0 || info->si_code == SI_TKILL) { |
da48524e JT |
2985 | /* We used to allow any < 0 si_code */ |
2986 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 2987 | return -EPERM; |
da48524e | 2988 | } |
62ab4505 TG |
2989 | info->si_signo = sig; |
2990 | ||
2991 | return do_send_specific(tgid, pid, sig, info); | |
2992 | } | |
2993 | ||
2994 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
2995 | siginfo_t __user *, uinfo) | |
2996 | { | |
2997 | siginfo_t info; | |
2998 | ||
2999 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3000 | return -EFAULT; | |
3001 | ||
3002 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3003 | } | |
3004 | ||
88531f72 | 3005 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3006 | { |
93585eea | 3007 | struct task_struct *t = current; |
1da177e4 | 3008 | struct k_sigaction *k; |
71fabd5e | 3009 | sigset_t mask; |
1da177e4 | 3010 | |
7ed20e1a | 3011 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3012 | return -EINVAL; |
3013 | ||
93585eea | 3014 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
3015 | |
3016 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
3017 | if (oact) |
3018 | *oact = *k; | |
3019 | ||
3020 | if (act) { | |
9ac95f2f ON |
3021 | sigdelsetmask(&act->sa.sa_mask, |
3022 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3023 | *k = *act; |
1da177e4 LT |
3024 | /* |
3025 | * POSIX 3.3.1.3: | |
3026 | * "Setting a signal action to SIG_IGN for a signal that is | |
3027 | * pending shall cause the pending signal to be discarded, | |
3028 | * whether or not it is blocked." | |
3029 | * | |
3030 | * "Setting a signal action to SIG_DFL for a signal that is | |
3031 | * pending and whose default action is to ignore the signal | |
3032 | * (for example, SIGCHLD), shall cause the pending signal to | |
3033 | * be discarded, whether or not it is blocked" | |
3034 | */ | |
35de254d | 3035 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
3036 | sigemptyset(&mask); |
3037 | sigaddset(&mask, sig); | |
3038 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 3039 | do { |
71fabd5e | 3040 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
3041 | t = next_thread(t); |
3042 | } while (t != current); | |
1da177e4 | 3043 | } |
1da177e4 LT |
3044 | } |
3045 | ||
3046 | spin_unlock_irq(¤t->sighand->siglock); | |
3047 | return 0; | |
3048 | } | |
3049 | ||
3050 | int | |
3051 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
3052 | { | |
3053 | stack_t oss; | |
3054 | int error; | |
3055 | ||
0083fc2c LT |
3056 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
3057 | oss.ss_size = current->sas_ss_size; | |
3058 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
3059 | |
3060 | if (uss) { | |
3061 | void __user *ss_sp; | |
3062 | size_t ss_size; | |
3063 | int ss_flags; | |
3064 | ||
3065 | error = -EFAULT; | |
0dd8486b LT |
3066 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
3067 | goto out; | |
3068 | error = __get_user(ss_sp, &uss->ss_sp) | | |
3069 | __get_user(ss_flags, &uss->ss_flags) | | |
3070 | __get_user(ss_size, &uss->ss_size); | |
3071 | if (error) | |
1da177e4 LT |
3072 | goto out; |
3073 | ||
3074 | error = -EPERM; | |
3075 | if (on_sig_stack(sp)) | |
3076 | goto out; | |
3077 | ||
3078 | error = -EINVAL; | |
3079 | /* | |
5aba085e | 3080 | * Note - this code used to test ss_flags incorrectly: |
1da177e4 LT |
3081 | * old code may have been written using ss_flags==0 |
3082 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
3083 | * way that worked) - this fix preserves that older | |
5aba085e | 3084 | * mechanism. |
1da177e4 LT |
3085 | */ |
3086 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
3087 | goto out; | |
3088 | ||
3089 | if (ss_flags == SS_DISABLE) { | |
3090 | ss_size = 0; | |
3091 | ss_sp = NULL; | |
3092 | } else { | |
3093 | error = -ENOMEM; | |
3094 | if (ss_size < MINSIGSTKSZ) | |
3095 | goto out; | |
3096 | } | |
3097 | ||
3098 | current->sas_ss_sp = (unsigned long) ss_sp; | |
3099 | current->sas_ss_size = ss_size; | |
3100 | } | |
3101 | ||
0083fc2c | 3102 | error = 0; |
1da177e4 LT |
3103 | if (uoss) { |
3104 | error = -EFAULT; | |
0083fc2c | 3105 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 3106 | goto out; |
0083fc2c LT |
3107 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
3108 | __put_user(oss.ss_size, &uoss->ss_size) | | |
3109 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
3110 | } |
3111 | ||
1da177e4 LT |
3112 | out: |
3113 | return error; | |
3114 | } | |
3115 | ||
3116 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3117 | ||
41c57892 RD |
3118 | /** |
3119 | * sys_sigpending - examine pending signals | |
3120 | * @set: where mask of pending signal is returned | |
3121 | */ | |
b290ebe2 | 3122 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 LT |
3123 | { |
3124 | return do_sigpending(set, sizeof(*set)); | |
3125 | } | |
3126 | ||
3127 | #endif | |
3128 | ||
3129 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3130 | /** |
3131 | * sys_sigprocmask - examine and change blocked signals | |
3132 | * @how: whether to add, remove, or set signals | |
b013c399 | 3133 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3134 | * @oset: previous value of signal mask if non-null |
3135 | * | |
5aba085e RD |
3136 | * Some platforms have their own version with special arguments; |
3137 | * others support only sys_rt_sigprocmask. | |
3138 | */ | |
1da177e4 | 3139 | |
b013c399 | 3140 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3141 | old_sigset_t __user *, oset) |
1da177e4 | 3142 | { |
1da177e4 | 3143 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3144 | sigset_t new_blocked; |
1da177e4 | 3145 | |
b013c399 | 3146 | old_set = current->blocked.sig[0]; |
1da177e4 | 3147 | |
b013c399 ON |
3148 | if (nset) { |
3149 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3150 | return -EFAULT; | |
1da177e4 LT |
3151 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); |
3152 | ||
2e4f7c77 | 3153 | new_blocked = current->blocked; |
1da177e4 | 3154 | |
1da177e4 | 3155 | switch (how) { |
1da177e4 | 3156 | case SIG_BLOCK: |
2e4f7c77 | 3157 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3158 | break; |
3159 | case SIG_UNBLOCK: | |
2e4f7c77 | 3160 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3161 | break; |
3162 | case SIG_SETMASK: | |
2e4f7c77 | 3163 | new_blocked.sig[0] = new_set; |
1da177e4 | 3164 | break; |
2e4f7c77 ON |
3165 | default: |
3166 | return -EINVAL; | |
1da177e4 LT |
3167 | } |
3168 | ||
77097ae5 | 3169 | __set_current_blocked(&new_blocked); |
b013c399 ON |
3170 | } |
3171 | ||
3172 | if (oset) { | |
1da177e4 | 3173 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3174 | return -EFAULT; |
1da177e4 | 3175 | } |
b013c399 ON |
3176 | |
3177 | return 0; | |
1da177e4 LT |
3178 | } |
3179 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3180 | ||
3181 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
41c57892 RD |
3182 | /** |
3183 | * sys_rt_sigaction - alter an action taken by a process | |
3184 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3185 | * @act: new sigaction |
3186 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3187 | * @sigsetsize: size of sigset_t type |
3188 | */ | |
d4e82042 HC |
3189 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3190 | const struct sigaction __user *, act, | |
3191 | struct sigaction __user *, oact, | |
3192 | size_t, sigsetsize) | |
1da177e4 LT |
3193 | { |
3194 | struct k_sigaction new_sa, old_sa; | |
3195 | int ret = -EINVAL; | |
3196 | ||
3197 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3198 | if (sigsetsize != sizeof(sigset_t)) | |
3199 | goto out; | |
3200 | ||
3201 | if (act) { | |
3202 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3203 | return -EFAULT; | |
3204 | } | |
3205 | ||
3206 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3207 | ||
3208 | if (!ret && oact) { | |
3209 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3210 | return -EFAULT; | |
3211 | } | |
3212 | out: | |
3213 | return ret; | |
3214 | } | |
3215 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
3216 | ||
3217 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
3218 | ||
3219 | /* | |
3220 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3221 | */ | |
a5f8fa9e | 3222 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3223 | { |
3224 | /* SMP safe */ | |
3225 | return current->blocked.sig[0]; | |
3226 | } | |
3227 | ||
a5f8fa9e | 3228 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3229 | { |
c1095c6d ON |
3230 | int old = current->blocked.sig[0]; |
3231 | sigset_t newset; | |
1da177e4 | 3232 | |
c1095c6d | 3233 | set_current_blocked(&newset); |
1da177e4 LT |
3234 | |
3235 | return old; | |
3236 | } | |
3237 | #endif /* __ARCH_WANT_SGETMASK */ | |
3238 | ||
3239 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3240 | /* | |
3241 | * For backwards compatibility. Functionality superseded by sigaction. | |
3242 | */ | |
a5f8fa9e | 3243 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3244 | { |
3245 | struct k_sigaction new_sa, old_sa; | |
3246 | int ret; | |
3247 | ||
3248 | new_sa.sa.sa_handler = handler; | |
3249 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3250 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3251 | |
3252 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3253 | ||
3254 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3255 | } | |
3256 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3257 | ||
3258 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3259 | ||
a5f8fa9e | 3260 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3261 | { |
d92fcf05 ON |
3262 | while (!signal_pending(current)) { |
3263 | current->state = TASK_INTERRUPTIBLE; | |
3264 | schedule(); | |
3265 | } | |
1da177e4 LT |
3266 | return -ERESTARTNOHAND; |
3267 | } | |
3268 | ||
3269 | #endif | |
3270 | ||
68f3f16d AV |
3271 | int sigsuspend(sigset_t *set) |
3272 | { | |
68f3f16d AV |
3273 | current->saved_sigmask = current->blocked; |
3274 | set_current_blocked(set); | |
3275 | ||
3276 | current->state = TASK_INTERRUPTIBLE; | |
3277 | schedule(); | |
3278 | set_restore_sigmask(); | |
3279 | return -ERESTARTNOHAND; | |
3280 | } | |
68f3f16d | 3281 | |
150256d8 | 3282 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
41c57892 RD |
3283 | /** |
3284 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3285 | * @unewset value until a signal is received | |
3286 | * @unewset: new signal mask value | |
3287 | * @sigsetsize: size of sigset_t type | |
3288 | */ | |
d4e82042 | 3289 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3290 | { |
3291 | sigset_t newset; | |
3292 | ||
3293 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3294 | if (sigsetsize != sizeof(sigset_t)) | |
3295 | return -EINVAL; | |
3296 | ||
3297 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3298 | return -EFAULT; | |
68f3f16d | 3299 | return sigsuspend(&newset); |
150256d8 DW |
3300 | } |
3301 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
3302 | ||
f269fdd1 DH |
3303 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
3304 | { | |
3305 | return NULL; | |
3306 | } | |
3307 | ||
1da177e4 LT |
3308 | void __init signals_init(void) |
3309 | { | |
0a31bd5f | 3310 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3311 | } |
67fc4e0c JW |
3312 | |
3313 | #ifdef CONFIG_KGDB_KDB | |
3314 | #include <linux/kdb.h> | |
3315 | /* | |
3316 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3317 | * signal internals. This function checks if the required locks are | |
3318 | * available before calling the main signal code, to avoid kdb | |
3319 | * deadlocks. | |
3320 | */ | |
3321 | void | |
3322 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3323 | { | |
3324 | static struct task_struct *kdb_prev_t; | |
3325 | int sig, new_t; | |
3326 | if (!spin_trylock(&t->sighand->siglock)) { | |
3327 | kdb_printf("Can't do kill command now.\n" | |
3328 | "The sigmask lock is held somewhere else in " | |
3329 | "kernel, try again later\n"); | |
3330 | return; | |
3331 | } | |
3332 | spin_unlock(&t->sighand->siglock); | |
3333 | new_t = kdb_prev_t != t; | |
3334 | kdb_prev_t = t; | |
3335 | if (t->state != TASK_RUNNING && new_t) { | |
3336 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3337 | "kdb risks deadlock\n" | |
3338 | "on the run queue locks. " | |
3339 | "The signal has _not_ been sent.\n" | |
3340 | "Reissue the kill command if you want to risk " | |
3341 | "the deadlock.\n"); | |
3342 | return; | |
3343 | } | |
3344 | sig = info->si_signo; | |
3345 | if (send_sig_info(sig, info, t)) | |
3346 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3347 | sig, t->pid); | |
3348 | else | |
3349 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3350 | } | |
3351 | #endif /* CONFIG_KGDB_KDB */ |