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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 | 13 | #include <linux/slab.h> |
9984de1a | 14 | #include <linux/export.h> |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
179899fd | 20 | #include <linux/coredump.h> |
1da177e4 LT |
21 | #include <linux/security.h> |
22 | #include <linux/syscalls.h> | |
23 | #include <linux/ptrace.h> | |
7ed20e1a | 24 | #include <linux/signal.h> |
fba2afaa | 25 | #include <linux/signalfd.h> |
f84d49b2 | 26 | #include <linux/ratelimit.h> |
35de254d | 27 | #include <linux/tracehook.h> |
c59ede7b | 28 | #include <linux/capability.h> |
7dfb7103 | 29 | #include <linux/freezer.h> |
84d73786 SB |
30 | #include <linux/pid_namespace.h> |
31 | #include <linux/nsproxy.h> | |
6b550f94 | 32 | #include <linux/user_namespace.h> |
0326f5a9 | 33 | #include <linux/uprobes.h> |
90268439 | 34 | #include <linux/compat.h> |
2b5faa4c | 35 | #include <linux/cn_proc.h> |
52f5684c GID |
36 | #include <linux/compiler.h> |
37 | ||
d1eb650f MH |
38 | #define CREATE_TRACE_POINTS |
39 | #include <trace/events/signal.h> | |
84d73786 | 40 | |
1da177e4 LT |
41 | #include <asm/param.h> |
42 | #include <asm/uaccess.h> | |
43 | #include <asm/unistd.h> | |
44 | #include <asm/siginfo.h> | |
d550bbd4 | 45 | #include <asm/cacheflush.h> |
e1396065 | 46 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
47 | |
48 | /* | |
49 | * SLAB caches for signal bits. | |
50 | */ | |
51 | ||
e18b890b | 52 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 53 | |
f84d49b2 NO |
54 | int print_fatal_signals __read_mostly; |
55 | ||
35de254d | 56 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 57 | { |
35de254d RM |
58 | return t->sighand->action[sig - 1].sa.sa_handler; |
59 | } | |
93585eea | 60 | |
35de254d RM |
61 | static int sig_handler_ignored(void __user *handler, int sig) |
62 | { | |
93585eea | 63 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
64 | return handler == SIG_IGN || |
65 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
66 | } | |
1da177e4 | 67 | |
def8cf72 | 68 | static int sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 69 | { |
35de254d | 70 | void __user *handler; |
1da177e4 | 71 | |
f008faff ON |
72 | handler = sig_handler(t, sig); |
73 | ||
74 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
def8cf72 | 75 | handler == SIG_DFL && !force) |
f008faff ON |
76 | return 1; |
77 | ||
78 | return sig_handler_ignored(handler, sig); | |
79 | } | |
80 | ||
def8cf72 | 81 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 82 | { |
1da177e4 LT |
83 | /* |
84 | * Blocked signals are never ignored, since the | |
85 | * signal handler may change by the time it is | |
86 | * unblocked. | |
87 | */ | |
325d22df | 88 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
89 | return 0; |
90 | ||
def8cf72 | 91 | if (!sig_task_ignored(t, sig, force)) |
35de254d RM |
92 | return 0; |
93 | ||
94 | /* | |
95 | * Tracers may want to know about even ignored signals. | |
96 | */ | |
a288eecc | 97 | return !t->ptrace; |
1da177e4 LT |
98 | } |
99 | ||
100 | /* | |
101 | * Re-calculate pending state from the set of locally pending | |
102 | * signals, globally pending signals, and blocked signals. | |
103 | */ | |
104 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
105 | { | |
106 | unsigned long ready; | |
107 | long i; | |
108 | ||
109 | switch (_NSIG_WORDS) { | |
110 | default: | |
111 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
112 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
113 | break; | |
114 | ||
115 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
116 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
117 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
118 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
119 | break; | |
120 | ||
121 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
122 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
123 | break; | |
124 | ||
125 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
126 | } | |
127 | return ready != 0; | |
128 | } | |
129 | ||
130 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
131 | ||
7bb44ade | 132 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 133 | { |
3759a0d9 | 134 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 135 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 136 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 137 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
138 | return 1; |
139 | } | |
b74d0deb RM |
140 | /* |
141 | * We must never clear the flag in another thread, or in current | |
142 | * when it's possible the current syscall is returning -ERESTART*. | |
143 | * So we don't clear it here, and only callers who know they should do. | |
144 | */ | |
7bb44ade RM |
145 | return 0; |
146 | } | |
147 | ||
148 | /* | |
149 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
150 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
151 | */ | |
152 | void recalc_sigpending_and_wake(struct task_struct *t) | |
153 | { | |
154 | if (recalc_sigpending_tsk(t)) | |
155 | signal_wake_up(t, 0); | |
1da177e4 LT |
156 | } |
157 | ||
158 | void recalc_sigpending(void) | |
159 | { | |
dd1d6772 | 160 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
161 | clear_thread_flag(TIF_SIGPENDING); |
162 | ||
1da177e4 LT |
163 | } |
164 | ||
165 | /* Given the mask, find the first available signal that should be serviced. */ | |
166 | ||
a27341cd LT |
167 | #define SYNCHRONOUS_MASK \ |
168 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 169 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 170 | |
fba2afaa | 171 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
172 | { |
173 | unsigned long i, *s, *m, x; | |
174 | int sig = 0; | |
f84d49b2 | 175 | |
1da177e4 LT |
176 | s = pending->signal.sig; |
177 | m = mask->sig; | |
a27341cd LT |
178 | |
179 | /* | |
180 | * Handle the first word specially: it contains the | |
181 | * synchronous signals that need to be dequeued first. | |
182 | */ | |
183 | x = *s &~ *m; | |
184 | if (x) { | |
185 | if (x & SYNCHRONOUS_MASK) | |
186 | x &= SYNCHRONOUS_MASK; | |
187 | sig = ffz(~x) + 1; | |
188 | return sig; | |
189 | } | |
190 | ||
1da177e4 LT |
191 | switch (_NSIG_WORDS) { |
192 | default: | |
a27341cd LT |
193 | for (i = 1; i < _NSIG_WORDS; ++i) { |
194 | x = *++s &~ *++m; | |
195 | if (!x) | |
196 | continue; | |
197 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
198 | break; | |
199 | } | |
1da177e4 LT |
200 | break; |
201 | ||
a27341cd LT |
202 | case 2: |
203 | x = s[1] &~ m[1]; | |
204 | if (!x) | |
1da177e4 | 205 | break; |
a27341cd | 206 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
207 | break; |
208 | ||
a27341cd LT |
209 | case 1: |
210 | /* Nothing to do */ | |
1da177e4 LT |
211 | break; |
212 | } | |
f84d49b2 | 213 | |
1da177e4 LT |
214 | return sig; |
215 | } | |
216 | ||
f84d49b2 NO |
217 | static inline void print_dropped_signal(int sig) |
218 | { | |
219 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
220 | ||
221 | if (!print_fatal_signals) | |
222 | return; | |
223 | ||
224 | if (!__ratelimit(&ratelimit_state)) | |
225 | return; | |
226 | ||
227 | printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", | |
228 | current->comm, current->pid, sig); | |
229 | } | |
230 | ||
d79fdd6d | 231 | /** |
7dd3db54 | 232 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 233 | * @task: target task |
7dd3db54 | 234 | * @mask: pending bits to set |
d79fdd6d | 235 | * |
7dd3db54 TH |
236 | * Clear @mask from @task->jobctl. @mask must be subset of |
237 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
238 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
239 | * cleared. If @task is already being killed or exiting, this function | |
240 | * becomes noop. | |
241 | * | |
242 | * CONTEXT: | |
243 | * Must be called with @task->sighand->siglock held. | |
244 | * | |
245 | * RETURNS: | |
246 | * %true if @mask is set, %false if made noop because @task was dying. | |
247 | */ | |
248 | bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask) | |
249 | { | |
250 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
251 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
252 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
253 | ||
254 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
255 | return false; | |
256 | ||
257 | if (mask & JOBCTL_STOP_SIGMASK) | |
258 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
259 | ||
260 | task->jobctl |= mask; | |
261 | return true; | |
262 | } | |
263 | ||
d79fdd6d | 264 | /** |
a8f072c1 | 265 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
266 | * @task: target task |
267 | * | |
a8f072c1 TH |
268 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
269 | * Clear it and wake up the ptracer. Note that we don't need any further | |
270 | * locking. @task->siglock guarantees that @task->parent points to the | |
271 | * ptracer. | |
d79fdd6d TH |
272 | * |
273 | * CONTEXT: | |
274 | * Must be called with @task->sighand->siglock held. | |
275 | */ | |
73ddff2b | 276 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 277 | { |
a8f072c1 TH |
278 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
279 | task->jobctl &= ~JOBCTL_TRAPPING; | |
650226bd | 280 | smp_mb(); /* advised by wake_up_bit() */ |
62c124ff | 281 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
282 | } |
283 | } | |
284 | ||
e5c1902e | 285 | /** |
3759a0d9 | 286 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 287 | * @task: target task |
3759a0d9 | 288 | * @mask: pending bits to clear |
e5c1902e | 289 | * |
3759a0d9 TH |
290 | * Clear @mask from @task->jobctl. @mask must be subset of |
291 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
292 | * STOP bits are cleared together. | |
e5c1902e | 293 | * |
6dfca329 TH |
294 | * If clearing of @mask leaves no stop or trap pending, this function calls |
295 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
296 | * |
297 | * CONTEXT: | |
298 | * Must be called with @task->sighand->siglock held. | |
299 | */ | |
3759a0d9 | 300 | void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask) |
e5c1902e | 301 | { |
3759a0d9 TH |
302 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
303 | ||
304 | if (mask & JOBCTL_STOP_PENDING) | |
305 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
306 | ||
307 | task->jobctl &= ~mask; | |
6dfca329 TH |
308 | |
309 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
310 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
311 | } |
312 | ||
313 | /** | |
314 | * task_participate_group_stop - participate in a group stop | |
315 | * @task: task participating in a group stop | |
316 | * | |
a8f072c1 | 317 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 318 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 319 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 320 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
321 | * |
322 | * CONTEXT: | |
323 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
324 | * |
325 | * RETURNS: | |
326 | * %true if group stop completion should be notified to the parent, %false | |
327 | * otherwise. | |
e5c1902e TH |
328 | */ |
329 | static bool task_participate_group_stop(struct task_struct *task) | |
330 | { | |
331 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 332 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 333 | |
a8f072c1 | 334 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 335 | |
3759a0d9 | 336 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
337 | |
338 | if (!consume) | |
339 | return false; | |
340 | ||
341 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
342 | sig->group_stop_count--; | |
343 | ||
244056f9 TH |
344 | /* |
345 | * Tell the caller to notify completion iff we are entering into a | |
346 | * fresh group stop. Read comment in do_signal_stop() for details. | |
347 | */ | |
348 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
e5c1902e TH |
349 | sig->flags = SIGNAL_STOP_STOPPED; |
350 | return true; | |
351 | } | |
352 | return false; | |
353 | } | |
354 | ||
c69e8d9c DH |
355 | /* |
356 | * allocate a new signal queue record | |
357 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 358 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 359 | */ |
f84d49b2 NO |
360 | static struct sigqueue * |
361 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
362 | { |
363 | struct sigqueue *q = NULL; | |
10b1fbdb | 364 | struct user_struct *user; |
1da177e4 | 365 | |
10b1fbdb | 366 | /* |
7cf7db8d TG |
367 | * Protect access to @t credentials. This can go away when all |
368 | * callers hold rcu read lock. | |
10b1fbdb | 369 | */ |
7cf7db8d | 370 | rcu_read_lock(); |
d84f4f99 | 371 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 372 | atomic_inc(&user->sigpending); |
7cf7db8d | 373 | rcu_read_unlock(); |
f84d49b2 | 374 | |
1da177e4 | 375 | if (override_rlimit || |
10b1fbdb | 376 | atomic_read(&user->sigpending) <= |
78d7d407 | 377 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 378 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
379 | } else { |
380 | print_dropped_signal(sig); | |
381 | } | |
382 | ||
1da177e4 | 383 | if (unlikely(q == NULL)) { |
10b1fbdb | 384 | atomic_dec(&user->sigpending); |
d84f4f99 | 385 | free_uid(user); |
1da177e4 LT |
386 | } else { |
387 | INIT_LIST_HEAD(&q->list); | |
388 | q->flags = 0; | |
d84f4f99 | 389 | q->user = user; |
1da177e4 | 390 | } |
d84f4f99 DH |
391 | |
392 | return q; | |
1da177e4 LT |
393 | } |
394 | ||
514a01b8 | 395 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
396 | { |
397 | if (q->flags & SIGQUEUE_PREALLOC) | |
398 | return; | |
399 | atomic_dec(&q->user->sigpending); | |
400 | free_uid(q->user); | |
401 | kmem_cache_free(sigqueue_cachep, q); | |
402 | } | |
403 | ||
6a14c5c9 | 404 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
405 | { |
406 | struct sigqueue *q; | |
407 | ||
408 | sigemptyset(&queue->signal); | |
409 | while (!list_empty(&queue->list)) { | |
410 | q = list_entry(queue->list.next, struct sigqueue , list); | |
411 | list_del_init(&q->list); | |
412 | __sigqueue_free(q); | |
413 | } | |
414 | } | |
415 | ||
416 | /* | |
417 | * Flush all pending signals for a task. | |
418 | */ | |
3bcac026 DH |
419 | void __flush_signals(struct task_struct *t) |
420 | { | |
421 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
422 | flush_sigqueue(&t->pending); | |
423 | flush_sigqueue(&t->signal->shared_pending); | |
424 | } | |
425 | ||
c81addc9 | 426 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
427 | { |
428 | unsigned long flags; | |
429 | ||
430 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
3bcac026 | 431 | __flush_signals(t); |
1da177e4 LT |
432 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
433 | } | |
434 | ||
cbaffba1 ON |
435 | static void __flush_itimer_signals(struct sigpending *pending) |
436 | { | |
437 | sigset_t signal, retain; | |
438 | struct sigqueue *q, *n; | |
439 | ||
440 | signal = pending->signal; | |
441 | sigemptyset(&retain); | |
442 | ||
443 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
444 | int sig = q->info.si_signo; | |
445 | ||
446 | if (likely(q->info.si_code != SI_TIMER)) { | |
447 | sigaddset(&retain, sig); | |
448 | } else { | |
449 | sigdelset(&signal, sig); | |
450 | list_del_init(&q->list); | |
451 | __sigqueue_free(q); | |
452 | } | |
453 | } | |
454 | ||
455 | sigorsets(&pending->signal, &signal, &retain); | |
456 | } | |
457 | ||
458 | void flush_itimer_signals(void) | |
459 | { | |
460 | struct task_struct *tsk = current; | |
461 | unsigned long flags; | |
462 | ||
463 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
464 | __flush_itimer_signals(&tsk->pending); | |
465 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
466 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
467 | } | |
468 | ||
10ab825b ON |
469 | void ignore_signals(struct task_struct *t) |
470 | { | |
471 | int i; | |
472 | ||
473 | for (i = 0; i < _NSIG; ++i) | |
474 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
475 | ||
476 | flush_signals(t); | |
477 | } | |
478 | ||
1da177e4 LT |
479 | /* |
480 | * Flush all handlers for a task. | |
481 | */ | |
482 | ||
483 | void | |
484 | flush_signal_handlers(struct task_struct *t, int force_default) | |
485 | { | |
486 | int i; | |
487 | struct k_sigaction *ka = &t->sighand->action[0]; | |
488 | for (i = _NSIG ; i != 0 ; i--) { | |
489 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
490 | ka->sa.sa_handler = SIG_DFL; | |
491 | ka->sa.sa_flags = 0; | |
522cff14 | 492 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
493 | ka->sa.sa_restorer = NULL; |
494 | #endif | |
1da177e4 LT |
495 | sigemptyset(&ka->sa.sa_mask); |
496 | ka++; | |
497 | } | |
498 | } | |
499 | ||
abd4f750 MAS |
500 | int unhandled_signal(struct task_struct *tsk, int sig) |
501 | { | |
445a91d2 | 502 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 503 | if (is_global_init(tsk)) |
abd4f750 | 504 | return 1; |
445a91d2 | 505 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 506 | return 0; |
a288eecc TH |
507 | /* if ptraced, let the tracer determine */ |
508 | return !tsk->ptrace; | |
abd4f750 MAS |
509 | } |
510 | ||
5aba085e RD |
511 | /* |
512 | * Notify the system that a driver wants to block all signals for this | |
1da177e4 LT |
513 | * process, and wants to be notified if any signals at all were to be |
514 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
515 | * signal will be acted upon after all. If the notifier routine returns 0, | |
516 | * then then signal will be blocked. Only one block per process is | |
517 | * allowed. priv is a pointer to private data that the notifier routine | |
5aba085e RD |
518 | * can use to determine if the signal should be blocked or not. |
519 | */ | |
1da177e4 LT |
520 | void |
521 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
522 | { | |
523 | unsigned long flags; | |
524 | ||
525 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
526 | current->notifier_mask = mask; | |
527 | current->notifier_data = priv; | |
528 | current->notifier = notifier; | |
529 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
530 | } | |
531 | ||
532 | /* Notify the system that blocking has ended. */ | |
533 | ||
534 | void | |
535 | unblock_all_signals(void) | |
536 | { | |
537 | unsigned long flags; | |
538 | ||
539 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
540 | current->notifier = NULL; | |
541 | current->notifier_data = NULL; | |
542 | recalc_sigpending(); | |
543 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
544 | } | |
545 | ||
100360f0 | 546 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
547 | { |
548 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 549 | |
1da177e4 LT |
550 | /* |
551 | * Collect the siginfo appropriate to this signal. Check if | |
552 | * there is another siginfo for the same signal. | |
553 | */ | |
554 | list_for_each_entry(q, &list->list, list) { | |
555 | if (q->info.si_signo == sig) { | |
d4434207 ON |
556 | if (first) |
557 | goto still_pending; | |
1da177e4 LT |
558 | first = q; |
559 | } | |
560 | } | |
d4434207 ON |
561 | |
562 | sigdelset(&list->signal, sig); | |
563 | ||
1da177e4 | 564 | if (first) { |
d4434207 | 565 | still_pending: |
1da177e4 LT |
566 | list_del_init(&first->list); |
567 | copy_siginfo(info, &first->info); | |
568 | __sigqueue_free(first); | |
1da177e4 | 569 | } else { |
5aba085e RD |
570 | /* |
571 | * Ok, it wasn't in the queue. This must be | |
572 | * a fast-pathed signal or we must have been | |
573 | * out of queue space. So zero out the info. | |
1da177e4 | 574 | */ |
1da177e4 LT |
575 | info->si_signo = sig; |
576 | info->si_errno = 0; | |
7486e5d9 | 577 | info->si_code = SI_USER; |
1da177e4 LT |
578 | info->si_pid = 0; |
579 | info->si_uid = 0; | |
580 | } | |
1da177e4 LT |
581 | } |
582 | ||
583 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
584 | siginfo_t *info) | |
585 | { | |
27d91e07 | 586 | int sig = next_signal(pending, mask); |
1da177e4 | 587 | |
1da177e4 LT |
588 | if (sig) { |
589 | if (current->notifier) { | |
590 | if (sigismember(current->notifier_mask, sig)) { | |
591 | if (!(current->notifier)(current->notifier_data)) { | |
592 | clear_thread_flag(TIF_SIGPENDING); | |
593 | return 0; | |
594 | } | |
595 | } | |
596 | } | |
597 | ||
100360f0 | 598 | collect_signal(sig, pending, info); |
1da177e4 | 599 | } |
1da177e4 LT |
600 | |
601 | return sig; | |
602 | } | |
603 | ||
604 | /* | |
5aba085e | 605 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
606 | * expected to free it. |
607 | * | |
608 | * All callers have to hold the siglock. | |
609 | */ | |
610 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
611 | { | |
c5363d03 | 612 | int signr; |
caec4e8d BH |
613 | |
614 | /* We only dequeue private signals from ourselves, we don't let | |
615 | * signalfd steal them | |
616 | */ | |
b8fceee1 | 617 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 618 | if (!signr) { |
1da177e4 LT |
619 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
620 | mask, info); | |
8bfd9a7a TG |
621 | /* |
622 | * itimer signal ? | |
623 | * | |
624 | * itimers are process shared and we restart periodic | |
625 | * itimers in the signal delivery path to prevent DoS | |
626 | * attacks in the high resolution timer case. This is | |
5aba085e | 627 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
628 | * itimers, as the SIGALRM is a legacy signal and only |
629 | * queued once. Changing the restart behaviour to | |
630 | * restart the timer in the signal dequeue path is | |
631 | * reducing the timer noise on heavy loaded !highres | |
632 | * systems too. | |
633 | */ | |
634 | if (unlikely(signr == SIGALRM)) { | |
635 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
636 | ||
637 | if (!hrtimer_is_queued(tmr) && | |
638 | tsk->signal->it_real_incr.tv64 != 0) { | |
639 | hrtimer_forward(tmr, tmr->base->get_time(), | |
640 | tsk->signal->it_real_incr); | |
641 | hrtimer_restart(tmr); | |
642 | } | |
643 | } | |
644 | } | |
c5363d03 | 645 | |
b8fceee1 | 646 | recalc_sigpending(); |
c5363d03 PE |
647 | if (!signr) |
648 | return 0; | |
649 | ||
650 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
651 | /* |
652 | * Set a marker that we have dequeued a stop signal. Our | |
653 | * caller might release the siglock and then the pending | |
654 | * stop signal it is about to process is no longer in the | |
655 | * pending bitmasks, but must still be cleared by a SIGCONT | |
656 | * (and overruled by a SIGKILL). So those cases clear this | |
657 | * shared flag after we've set it. Note that this flag may | |
658 | * remain set after the signal we return is ignored or | |
659 | * handled. That doesn't matter because its only purpose | |
660 | * is to alert stop-signal processing code when another | |
661 | * processor has come along and cleared the flag. | |
662 | */ | |
a8f072c1 | 663 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 664 | } |
c5363d03 | 665 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
666 | /* |
667 | * Release the siglock to ensure proper locking order | |
668 | * of timer locks outside of siglocks. Note, we leave | |
669 | * irqs disabled here, since the posix-timers code is | |
670 | * about to disable them again anyway. | |
671 | */ | |
672 | spin_unlock(&tsk->sighand->siglock); | |
673 | do_schedule_next_timer(info); | |
674 | spin_lock(&tsk->sighand->siglock); | |
675 | } | |
676 | return signr; | |
677 | } | |
678 | ||
679 | /* | |
680 | * Tell a process that it has a new active signal.. | |
681 | * | |
682 | * NOTE! we rely on the previous spin_lock to | |
683 | * lock interrupts for us! We can only be called with | |
684 | * "siglock" held, and the local interrupt must | |
685 | * have been disabled when that got acquired! | |
686 | * | |
687 | * No need to set need_resched since signal event passing | |
688 | * goes through ->blocked | |
689 | */ | |
910ffdb1 | 690 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 691 | { |
1da177e4 | 692 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 693 | /* |
910ffdb1 | 694 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 695 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
696 | * executing another processor and just now entering stopped state. |
697 | * By using wake_up_state, we ensure the process will wake up and | |
698 | * handle its death signal. | |
699 | */ | |
910ffdb1 | 700 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
701 | kick_process(t); |
702 | } | |
703 | ||
71fabd5e GA |
704 | /* |
705 | * Remove signals in mask from the pending set and queue. | |
706 | * Returns 1 if any signals were found. | |
707 | * | |
708 | * All callers must be holding the siglock. | |
709 | * | |
710 | * This version takes a sigset mask and looks at all signals, | |
711 | * not just those in the first mask word. | |
712 | */ | |
713 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
714 | { | |
715 | struct sigqueue *q, *n; | |
716 | sigset_t m; | |
717 | ||
718 | sigandsets(&m, mask, &s->signal); | |
719 | if (sigisemptyset(&m)) | |
720 | return 0; | |
721 | ||
702a5073 | 722 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
723 | list_for_each_entry_safe(q, n, &s->list, list) { |
724 | if (sigismember(mask, q->info.si_signo)) { | |
725 | list_del_init(&q->list); | |
726 | __sigqueue_free(q); | |
727 | } | |
728 | } | |
729 | return 1; | |
730 | } | |
1da177e4 LT |
731 | /* |
732 | * Remove signals in mask from the pending set and queue. | |
733 | * Returns 1 if any signals were found. | |
734 | * | |
735 | * All callers must be holding the siglock. | |
736 | */ | |
737 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
738 | { | |
739 | struct sigqueue *q, *n; | |
740 | ||
741 | if (!sigtestsetmask(&s->signal, mask)) | |
742 | return 0; | |
743 | ||
744 | sigdelsetmask(&s->signal, mask); | |
745 | list_for_each_entry_safe(q, n, &s->list, list) { | |
746 | if (q->info.si_signo < SIGRTMIN && | |
747 | (mask & sigmask(q->info.si_signo))) { | |
748 | list_del_init(&q->list); | |
749 | __sigqueue_free(q); | |
750 | } | |
751 | } | |
752 | return 1; | |
753 | } | |
754 | ||
614c517d ON |
755 | static inline int is_si_special(const struct siginfo *info) |
756 | { | |
757 | return info <= SEND_SIG_FORCED; | |
758 | } | |
759 | ||
760 | static inline bool si_fromuser(const struct siginfo *info) | |
761 | { | |
762 | return info == SEND_SIG_NOINFO || | |
763 | (!is_si_special(info) && SI_FROMUSER(info)); | |
764 | } | |
765 | ||
39fd3393 SH |
766 | /* |
767 | * called with RCU read lock from check_kill_permission() | |
768 | */ | |
769 | static int kill_ok_by_cred(struct task_struct *t) | |
770 | { | |
771 | const struct cred *cred = current_cred(); | |
772 | const struct cred *tcred = __task_cred(t); | |
773 | ||
5af66203 EB |
774 | if (uid_eq(cred->euid, tcred->suid) || |
775 | uid_eq(cred->euid, tcred->uid) || | |
776 | uid_eq(cred->uid, tcred->suid) || | |
777 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
778 | return 1; |
779 | ||
c4a4d603 | 780 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
781 | return 1; |
782 | ||
783 | return 0; | |
784 | } | |
785 | ||
1da177e4 LT |
786 | /* |
787 | * Bad permissions for sending the signal | |
694f690d | 788 | * - the caller must hold the RCU read lock |
1da177e4 LT |
789 | */ |
790 | static int check_kill_permission(int sig, struct siginfo *info, | |
791 | struct task_struct *t) | |
792 | { | |
2e2ba22e | 793 | struct pid *sid; |
3b5e9e53 ON |
794 | int error; |
795 | ||
7ed20e1a | 796 | if (!valid_signal(sig)) |
3b5e9e53 ON |
797 | return -EINVAL; |
798 | ||
614c517d | 799 | if (!si_fromuser(info)) |
3b5e9e53 | 800 | return 0; |
e54dc243 | 801 | |
3b5e9e53 ON |
802 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
803 | if (error) | |
1da177e4 | 804 | return error; |
3b5e9e53 | 805 | |
065add39 | 806 | if (!same_thread_group(current, t) && |
39fd3393 | 807 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
808 | switch (sig) { |
809 | case SIGCONT: | |
2e2ba22e | 810 | sid = task_session(t); |
2e2ba22e ON |
811 | /* |
812 | * We don't return the error if sid == NULL. The | |
813 | * task was unhashed, the caller must notice this. | |
814 | */ | |
815 | if (!sid || sid == task_session(current)) | |
816 | break; | |
817 | default: | |
818 | return -EPERM; | |
819 | } | |
820 | } | |
c2f0c7c3 | 821 | |
e54dc243 | 822 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
823 | } |
824 | ||
fb1d910c TH |
825 | /** |
826 | * ptrace_trap_notify - schedule trap to notify ptracer | |
827 | * @t: tracee wanting to notify tracer | |
828 | * | |
829 | * This function schedules sticky ptrace trap which is cleared on the next | |
830 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
831 | * ptracer. | |
832 | * | |
544b2c91 TH |
833 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
834 | * ptracer is listening for events, tracee is woken up so that it can | |
835 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
836 | * eventually taken without returning to userland after the existing traps | |
837 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
838 | * |
839 | * CONTEXT: | |
840 | * Must be called with @task->sighand->siglock held. | |
841 | */ | |
842 | static void ptrace_trap_notify(struct task_struct *t) | |
843 | { | |
844 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
845 | assert_spin_locked(&t->sighand->siglock); | |
846 | ||
847 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 848 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
849 | } |
850 | ||
1da177e4 | 851 | /* |
7e695a5e ON |
852 | * Handle magic process-wide effects of stop/continue signals. Unlike |
853 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
854 | * time regardless of blocking, ignoring, or handling. This does the |
855 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
856 | * signals. The process stop is done as a signal action for SIG_DFL. |
857 | * | |
858 | * Returns true if the signal should be actually delivered, otherwise | |
859 | * it should be dropped. | |
1da177e4 | 860 | */ |
403bad72 | 861 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 862 | { |
ad16a460 | 863 | struct signal_struct *signal = p->signal; |
1da177e4 LT |
864 | struct task_struct *t; |
865 | ||
403bad72 ON |
866 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { |
867 | if (signal->flags & SIGNAL_GROUP_COREDUMP) | |
868 | return sig == SIGKILL; | |
1da177e4 | 869 | /* |
7e695a5e | 870 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 871 | */ |
7e695a5e | 872 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
873 | /* |
874 | * This is a stop signal. Remove SIGCONT from all queues. | |
875 | */ | |
ad16a460 | 876 | rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); |
1da177e4 LT |
877 | t = p; |
878 | do { | |
879 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
ad16a460 | 880 | } while_each_thread(p, t); |
1da177e4 | 881 | } else if (sig == SIGCONT) { |
fc321d2e | 882 | unsigned int why; |
1da177e4 | 883 | /* |
1deac632 | 884 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 885 | */ |
ad16a460 | 886 | rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); |
1da177e4 LT |
887 | t = p; |
888 | do { | |
3759a0d9 | 889 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
1da177e4 | 890 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); |
fb1d910c TH |
891 | if (likely(!(t->ptrace & PT_SEIZED))) |
892 | wake_up_state(t, __TASK_STOPPED); | |
893 | else | |
894 | ptrace_trap_notify(t); | |
ad16a460 | 895 | } while_each_thread(p, t); |
1da177e4 | 896 | |
fc321d2e ON |
897 | /* |
898 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
899 | * | |
900 | * If we were in the middle of a group stop, we pretend it | |
901 | * was already finished, and then continued. Since SIGCHLD | |
902 | * doesn't queue we report only CLD_STOPPED, as if the next | |
903 | * CLD_CONTINUED was dropped. | |
904 | */ | |
905 | why = 0; | |
ad16a460 | 906 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 907 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 908 | else if (signal->group_stop_count) |
fc321d2e ON |
909 | why |= SIGNAL_CLD_STOPPED; |
910 | ||
911 | if (why) { | |
021e1ae3 | 912 | /* |
ae6d2ed7 | 913 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
914 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
915 | * notify its parent. See get_signal_to_deliver(). | |
916 | */ | |
ad16a460 ON |
917 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
918 | signal->group_stop_count = 0; | |
919 | signal->group_exit_code = 0; | |
1da177e4 | 920 | } |
1da177e4 | 921 | } |
7e695a5e | 922 | |
def8cf72 | 923 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
924 | } |
925 | ||
71f11dc0 ON |
926 | /* |
927 | * Test if P wants to take SIG. After we've checked all threads with this, | |
928 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
929 | * blocking SIG were ruled out because they are not running and already | |
930 | * have pending signals. Such threads will dequeue from the shared queue | |
931 | * as soon as they're available, so putting the signal on the shared queue | |
932 | * will be equivalent to sending it to one such thread. | |
933 | */ | |
934 | static inline int wants_signal(int sig, struct task_struct *p) | |
935 | { | |
936 | if (sigismember(&p->blocked, sig)) | |
937 | return 0; | |
938 | if (p->flags & PF_EXITING) | |
939 | return 0; | |
940 | if (sig == SIGKILL) | |
941 | return 1; | |
942 | if (task_is_stopped_or_traced(p)) | |
943 | return 0; | |
944 | return task_curr(p) || !signal_pending(p); | |
945 | } | |
946 | ||
5fcd835b | 947 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
948 | { |
949 | struct signal_struct *signal = p->signal; | |
950 | struct task_struct *t; | |
951 | ||
952 | /* | |
953 | * Now find a thread we can wake up to take the signal off the queue. | |
954 | * | |
955 | * If the main thread wants the signal, it gets first crack. | |
956 | * Probably the least surprising to the average bear. | |
957 | */ | |
958 | if (wants_signal(sig, p)) | |
959 | t = p; | |
5fcd835b | 960 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
961 | /* |
962 | * There is just one thread and it does not need to be woken. | |
963 | * It will dequeue unblocked signals before it runs again. | |
964 | */ | |
965 | return; | |
966 | else { | |
967 | /* | |
968 | * Otherwise try to find a suitable thread. | |
969 | */ | |
970 | t = signal->curr_target; | |
971 | while (!wants_signal(sig, t)) { | |
972 | t = next_thread(t); | |
973 | if (t == signal->curr_target) | |
974 | /* | |
975 | * No thread needs to be woken. | |
976 | * Any eligible threads will see | |
977 | * the signal in the queue soon. | |
978 | */ | |
979 | return; | |
980 | } | |
981 | signal->curr_target = t; | |
982 | } | |
983 | ||
984 | /* | |
985 | * Found a killable thread. If the signal will be fatal, | |
986 | * then start taking the whole group down immediately. | |
987 | */ | |
fae5fa44 ON |
988 | if (sig_fatal(p, sig) && |
989 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 990 | !sigismember(&t->real_blocked, sig) && |
a288eecc | 991 | (sig == SIGKILL || !t->ptrace)) { |
71f11dc0 ON |
992 | /* |
993 | * This signal will be fatal to the whole group. | |
994 | */ | |
995 | if (!sig_kernel_coredump(sig)) { | |
996 | /* | |
997 | * Start a group exit and wake everybody up. | |
998 | * This way we don't have other threads | |
999 | * running and doing things after a slower | |
1000 | * thread has the fatal signal pending. | |
1001 | */ | |
1002 | signal->flags = SIGNAL_GROUP_EXIT; | |
1003 | signal->group_exit_code = sig; | |
1004 | signal->group_stop_count = 0; | |
1005 | t = p; | |
1006 | do { | |
6dfca329 | 1007 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
1008 | sigaddset(&t->pending.signal, SIGKILL); |
1009 | signal_wake_up(t, 1); | |
1010 | } while_each_thread(p, t); | |
1011 | return; | |
1012 | } | |
1013 | } | |
1014 | ||
1015 | /* | |
1016 | * The signal is already in the shared-pending queue. | |
1017 | * Tell the chosen thread to wake up and dequeue it. | |
1018 | */ | |
1019 | signal_wake_up(t, sig == SIGKILL); | |
1020 | return; | |
1021 | } | |
1022 | ||
af7fff9c PE |
1023 | static inline int legacy_queue(struct sigpending *signals, int sig) |
1024 | { | |
1025 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
1026 | } | |
1027 | ||
6b550f94 SH |
1028 | #ifdef CONFIG_USER_NS |
1029 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1030 | { | |
1031 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
1032 | return; | |
1033 | ||
1034 | if (SI_FROMKERNEL(info)) | |
1035 | return; | |
1036 | ||
078de5f7 EB |
1037 | rcu_read_lock(); |
1038 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
1039 | make_kuid(current_user_ns(), info->si_uid)); | |
1040 | rcu_read_unlock(); | |
6b550f94 SH |
1041 | } |
1042 | #else | |
1043 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1044 | { | |
1045 | return; | |
1046 | } | |
1047 | #endif | |
1048 | ||
7978b567 SB |
1049 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1050 | int group, int from_ancestor_ns) | |
1da177e4 | 1051 | { |
2ca3515a | 1052 | struct sigpending *pending; |
6e65acba | 1053 | struct sigqueue *q; |
7a0aeb14 | 1054 | int override_rlimit; |
6c303d3a | 1055 | int ret = 0, result; |
0a16b607 | 1056 | |
6e65acba | 1057 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1058 | |
6c303d3a | 1059 | result = TRACE_SIGNAL_IGNORED; |
629d362b ON |
1060 | if (!prepare_signal(sig, t, |
1061 | from_ancestor_ns || (info == SEND_SIG_FORCED))) | |
6c303d3a | 1062 | goto ret; |
2ca3515a ON |
1063 | |
1064 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
1065 | /* |
1066 | * Short-circuit ignored signals and support queuing | |
1067 | * exactly one non-rt signal, so that we can get more | |
1068 | * detailed information about the cause of the signal. | |
1069 | */ | |
6c303d3a | 1070 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1071 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1072 | goto ret; |
1073 | ||
1074 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1075 | /* |
1076 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1077 | * or SIGKILL. | |
1078 | */ | |
b67a1b9e | 1079 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1080 | goto out_set; |
1081 | ||
5aba085e RD |
1082 | /* |
1083 | * Real-time signals must be queued if sent by sigqueue, or | |
1084 | * some other real-time mechanism. It is implementation | |
1085 | * defined whether kill() does so. We attempt to do so, on | |
1086 | * the principle of least surprise, but since kill is not | |
1087 | * allowed to fail with EAGAIN when low on memory we just | |
1088 | * make sure at least one signal gets delivered and don't | |
1089 | * pass on the info struct. | |
1090 | */ | |
7a0aeb14 VN |
1091 | if (sig < SIGRTMIN) |
1092 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1093 | else | |
1094 | override_rlimit = 0; | |
1095 | ||
f84d49b2 | 1096 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1097 | override_rlimit); |
1da177e4 | 1098 | if (q) { |
2ca3515a | 1099 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1100 | switch ((unsigned long) info) { |
b67a1b9e | 1101 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1102 | q->info.si_signo = sig; |
1103 | q->info.si_errno = 0; | |
1104 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1105 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1106 | task_active_pid_ns(t)); |
078de5f7 | 1107 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1108 | break; |
b67a1b9e | 1109 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1110 | q->info.si_signo = sig; |
1111 | q->info.si_errno = 0; | |
1112 | q->info.si_code = SI_KERNEL; | |
1113 | q->info.si_pid = 0; | |
1114 | q->info.si_uid = 0; | |
1115 | break; | |
1116 | default: | |
1117 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1118 | if (from_ancestor_ns) |
1119 | q->info.si_pid = 0; | |
1da177e4 LT |
1120 | break; |
1121 | } | |
6b550f94 SH |
1122 | |
1123 | userns_fixup_signal_uid(&q->info, t); | |
1124 | ||
621d3121 | 1125 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1126 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1127 | /* | |
1128 | * Queue overflow, abort. We may abort if the | |
1129 | * signal was rt and sent by user using something | |
1130 | * other than kill(). | |
1131 | */ | |
6c303d3a ON |
1132 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1133 | ret = -EAGAIN; | |
1134 | goto ret; | |
ba005e1f MH |
1135 | } else { |
1136 | /* | |
1137 | * This is a silent loss of information. We still | |
1138 | * send the signal, but the *info bits are lost. | |
1139 | */ | |
6c303d3a | 1140 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1141 | } |
1da177e4 LT |
1142 | } |
1143 | ||
1144 | out_set: | |
53c30337 | 1145 | signalfd_notify(t, sig); |
2ca3515a | 1146 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1147 | complete_signal(sig, t, group); |
6c303d3a ON |
1148 | ret: |
1149 | trace_signal_generate(sig, info, t, group, result); | |
1150 | return ret; | |
1da177e4 LT |
1151 | } |
1152 | ||
7978b567 SB |
1153 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1154 | int group) | |
1155 | { | |
921cf9f6 SB |
1156 | int from_ancestor_ns = 0; |
1157 | ||
1158 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1159 | from_ancestor_ns = si_fromuser(info) && |
1160 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1161 | #endif |
1162 | ||
1163 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1164 | } |
1165 | ||
4aaefee5 | 1166 | static void print_fatal_signal(int signr) |
45807a1d | 1167 | { |
4aaefee5 | 1168 | struct pt_regs *regs = signal_pt_regs(); |
681a90ff | 1169 | printk(KERN_INFO "potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1170 | |
ca5cd877 | 1171 | #if defined(__i386__) && !defined(__arch_um__) |
5d1fadc1 | 1172 | printk(KERN_INFO "code at %08lx: ", regs->ip); |
45807a1d IM |
1173 | { |
1174 | int i; | |
1175 | for (i = 0; i < 16; i++) { | |
1176 | unsigned char insn; | |
1177 | ||
b45c6e76 AK |
1178 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1179 | break; | |
5d1fadc1 | 1180 | printk(KERN_CONT "%02x ", insn); |
45807a1d IM |
1181 | } |
1182 | } | |
5d1fadc1 | 1183 | printk(KERN_CONT "\n"); |
45807a1d | 1184 | #endif |
3a9f84d3 | 1185 | preempt_disable(); |
45807a1d | 1186 | show_regs(regs); |
3a9f84d3 | 1187 | preempt_enable(); |
45807a1d IM |
1188 | } |
1189 | ||
1190 | static int __init setup_print_fatal_signals(char *str) | |
1191 | { | |
1192 | get_option (&str, &print_fatal_signals); | |
1193 | ||
1194 | return 1; | |
1195 | } | |
1196 | ||
1197 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1198 | |
4cd4b6d4 PE |
1199 | int |
1200 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1201 | { | |
1202 | return send_signal(sig, info, p, 1); | |
1203 | } | |
1204 | ||
1da177e4 LT |
1205 | static int |
1206 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1207 | { | |
4cd4b6d4 | 1208 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1209 | } |
1210 | ||
4a30debf ON |
1211 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1212 | bool group) | |
1213 | { | |
1214 | unsigned long flags; | |
1215 | int ret = -ESRCH; | |
1216 | ||
1217 | if (lock_task_sighand(p, &flags)) { | |
1218 | ret = send_signal(sig, info, p, group); | |
1219 | unlock_task_sighand(p, &flags); | |
1220 | } | |
1221 | ||
1222 | return ret; | |
1223 | } | |
1224 | ||
1da177e4 LT |
1225 | /* |
1226 | * Force a signal that the process can't ignore: if necessary | |
1227 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1228 | * |
1229 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1230 | * since we do not want to have a signal handler that was blocked | |
1231 | * be invoked when user space had explicitly blocked it. | |
1232 | * | |
80fe728d ON |
1233 | * We don't want to have recursive SIGSEGV's etc, for example, |
1234 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1235 | */ |
1da177e4 LT |
1236 | int |
1237 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1238 | { | |
1239 | unsigned long int flags; | |
ae74c3b6 LT |
1240 | int ret, blocked, ignored; |
1241 | struct k_sigaction *action; | |
1da177e4 LT |
1242 | |
1243 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1244 | action = &t->sighand->action[sig-1]; |
1245 | ignored = action->sa.sa_handler == SIG_IGN; | |
1246 | blocked = sigismember(&t->blocked, sig); | |
1247 | if (blocked || ignored) { | |
1248 | action->sa.sa_handler = SIG_DFL; | |
1249 | if (blocked) { | |
1250 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1251 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1252 | } |
1da177e4 | 1253 | } |
80fe728d ON |
1254 | if (action->sa.sa_handler == SIG_DFL) |
1255 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1256 | ret = specific_send_sig_info(sig, info, t); |
1257 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1258 | ||
1259 | return ret; | |
1260 | } | |
1261 | ||
1da177e4 LT |
1262 | /* |
1263 | * Nuke all other threads in the group. | |
1264 | */ | |
09faef11 | 1265 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1266 | { |
09faef11 ON |
1267 | struct task_struct *t = p; |
1268 | int count = 0; | |
1da177e4 | 1269 | |
1da177e4 LT |
1270 | p->signal->group_stop_count = 0; |
1271 | ||
09faef11 | 1272 | while_each_thread(p, t) { |
6dfca329 | 1273 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1274 | count++; |
1275 | ||
1276 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1277 | if (t->exit_state) |
1278 | continue; | |
1da177e4 | 1279 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1280 | signal_wake_up(t, 1); |
1281 | } | |
09faef11 ON |
1282 | |
1283 | return count; | |
1da177e4 LT |
1284 | } |
1285 | ||
b8ed374e NK |
1286 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1287 | unsigned long *flags) | |
f63ee72e ON |
1288 | { |
1289 | struct sighand_struct *sighand; | |
1290 | ||
1291 | for (;;) { | |
a841796f PM |
1292 | local_irq_save(*flags); |
1293 | rcu_read_lock(); | |
f63ee72e | 1294 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1295 | if (unlikely(sighand == NULL)) { |
1296 | rcu_read_unlock(); | |
1297 | local_irq_restore(*flags); | |
f63ee72e | 1298 | break; |
a841796f | 1299 | } |
f63ee72e | 1300 | |
a841796f PM |
1301 | spin_lock(&sighand->siglock); |
1302 | if (likely(sighand == tsk->sighand)) { | |
1303 | rcu_read_unlock(); | |
f63ee72e | 1304 | break; |
a841796f PM |
1305 | } |
1306 | spin_unlock(&sighand->siglock); | |
1307 | rcu_read_unlock(); | |
1308 | local_irq_restore(*flags); | |
f63ee72e ON |
1309 | } |
1310 | ||
1311 | return sighand; | |
1312 | } | |
1313 | ||
c69e8d9c DH |
1314 | /* |
1315 | * send signal info to all the members of a group | |
c69e8d9c | 1316 | */ |
1da177e4 LT |
1317 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1318 | { | |
694f690d DH |
1319 | int ret; |
1320 | ||
1321 | rcu_read_lock(); | |
1322 | ret = check_kill_permission(sig, info, p); | |
1323 | rcu_read_unlock(); | |
f63ee72e | 1324 | |
4a30debf ON |
1325 | if (!ret && sig) |
1326 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1327 | |
1328 | return ret; | |
1329 | } | |
1330 | ||
1331 | /* | |
146a505d | 1332 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1333 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1334 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1335 | */ |
c4b92fc1 | 1336 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1337 | { |
1338 | struct task_struct *p = NULL; | |
1339 | int retval, success; | |
1340 | ||
1da177e4 LT |
1341 | success = 0; |
1342 | retval = -ESRCH; | |
c4b92fc1 | 1343 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1344 | int err = group_send_sig_info(sig, info, p); |
1345 | success |= !err; | |
1346 | retval = err; | |
c4b92fc1 | 1347 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1348 | return success ? 0 : retval; |
1349 | } | |
1350 | ||
c4b92fc1 | 1351 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1352 | { |
d36174bc | 1353 | int error = -ESRCH; |
1da177e4 LT |
1354 | struct task_struct *p; |
1355 | ||
e56d0903 | 1356 | rcu_read_lock(); |
d36174bc | 1357 | retry: |
c4b92fc1 | 1358 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1359 | if (p) { |
1da177e4 | 1360 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1361 | if (unlikely(error == -ESRCH)) |
1362 | /* | |
1363 | * The task was unhashed in between, try again. | |
1364 | * If it is dead, pid_task() will return NULL, | |
1365 | * if we race with de_thread() it will find the | |
1366 | * new leader. | |
1367 | */ | |
1368 | goto retry; | |
1369 | } | |
e56d0903 | 1370 | rcu_read_unlock(); |
6ca25b55 | 1371 | |
1da177e4 LT |
1372 | return error; |
1373 | } | |
1374 | ||
5aba085e | 1375 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1376 | { |
1377 | int error; | |
1378 | rcu_read_lock(); | |
b488893a | 1379 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1380 | rcu_read_unlock(); |
1381 | return error; | |
1382 | } | |
1383 | ||
d178bc3a SH |
1384 | static int kill_as_cred_perm(const struct cred *cred, |
1385 | struct task_struct *target) | |
1386 | { | |
1387 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1388 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1389 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1390 | return 0; |
1391 | return 1; | |
1392 | } | |
1393 | ||
2425c08b | 1394 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1395 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1396 | const struct cred *cred, u32 secid) | |
46113830 HW |
1397 | { |
1398 | int ret = -EINVAL; | |
1399 | struct task_struct *p; | |
14d8c9f3 | 1400 | unsigned long flags; |
46113830 HW |
1401 | |
1402 | if (!valid_signal(sig)) | |
1403 | return ret; | |
1404 | ||
14d8c9f3 | 1405 | rcu_read_lock(); |
2425c08b | 1406 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1407 | if (!p) { |
1408 | ret = -ESRCH; | |
1409 | goto out_unlock; | |
1410 | } | |
d178bc3a | 1411 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1412 | ret = -EPERM; |
1413 | goto out_unlock; | |
1414 | } | |
8f95dc58 DQ |
1415 | ret = security_task_kill(p, info, sig, secid); |
1416 | if (ret) | |
1417 | goto out_unlock; | |
14d8c9f3 TG |
1418 | |
1419 | if (sig) { | |
1420 | if (lock_task_sighand(p, &flags)) { | |
1421 | ret = __send_signal(sig, info, p, 1, 0); | |
1422 | unlock_task_sighand(p, &flags); | |
1423 | } else | |
1424 | ret = -ESRCH; | |
46113830 HW |
1425 | } |
1426 | out_unlock: | |
14d8c9f3 | 1427 | rcu_read_unlock(); |
46113830 HW |
1428 | return ret; |
1429 | } | |
d178bc3a | 1430 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1431 | |
1432 | /* | |
1433 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1434 | * | |
1435 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1436 | * is probably wrong. Should make it like BSD or SYSV. | |
1437 | */ | |
1438 | ||
bc64efd2 | 1439 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1440 | { |
8d42db18 | 1441 | int ret; |
d5df763b PE |
1442 | |
1443 | if (pid > 0) { | |
1444 | rcu_read_lock(); | |
1445 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1446 | rcu_read_unlock(); | |
1447 | return ret; | |
1448 | } | |
1449 | ||
1450 | read_lock(&tasklist_lock); | |
1451 | if (pid != -1) { | |
1452 | ret = __kill_pgrp_info(sig, info, | |
1453 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1454 | } else { | |
1da177e4 LT |
1455 | int retval = 0, count = 0; |
1456 | struct task_struct * p; | |
1457 | ||
1da177e4 | 1458 | for_each_process(p) { |
d25141a8 SB |
1459 | if (task_pid_vnr(p) > 1 && |
1460 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1461 | int err = group_send_sig_info(sig, info, p); |
1462 | ++count; | |
1463 | if (err != -EPERM) | |
1464 | retval = err; | |
1465 | } | |
1466 | } | |
8d42db18 | 1467 | ret = count ? retval : -ESRCH; |
1da177e4 | 1468 | } |
d5df763b PE |
1469 | read_unlock(&tasklist_lock); |
1470 | ||
8d42db18 | 1471 | return ret; |
1da177e4 LT |
1472 | } |
1473 | ||
1474 | /* | |
1475 | * These are for backward compatibility with the rest of the kernel source. | |
1476 | */ | |
1477 | ||
5aba085e | 1478 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1479 | { |
1da177e4 LT |
1480 | /* |
1481 | * Make sure legacy kernel users don't send in bad values | |
1482 | * (normal paths check this in check_kill_permission). | |
1483 | */ | |
7ed20e1a | 1484 | if (!valid_signal(sig)) |
1da177e4 LT |
1485 | return -EINVAL; |
1486 | ||
4a30debf | 1487 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1488 | } |
1489 | ||
b67a1b9e ON |
1490 | #define __si_special(priv) \ |
1491 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1492 | ||
1da177e4 LT |
1493 | int |
1494 | send_sig(int sig, struct task_struct *p, int priv) | |
1495 | { | |
b67a1b9e | 1496 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1497 | } |
1498 | ||
1da177e4 LT |
1499 | void |
1500 | force_sig(int sig, struct task_struct *p) | |
1501 | { | |
b67a1b9e | 1502 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1503 | } |
1504 | ||
1505 | /* | |
1506 | * When things go south during signal handling, we | |
1507 | * will force a SIGSEGV. And if the signal that caused | |
1508 | * the problem was already a SIGSEGV, we'll want to | |
1509 | * make sure we don't even try to deliver the signal.. | |
1510 | */ | |
1511 | int | |
1512 | force_sigsegv(int sig, struct task_struct *p) | |
1513 | { | |
1514 | if (sig == SIGSEGV) { | |
1515 | unsigned long flags; | |
1516 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1517 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1518 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1519 | } | |
1520 | force_sig(SIGSEGV, p); | |
1521 | return 0; | |
1522 | } | |
1523 | ||
c4b92fc1 EB |
1524 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1525 | { | |
146a505d PE |
1526 | int ret; |
1527 | ||
1528 | read_lock(&tasklist_lock); | |
1529 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1530 | read_unlock(&tasklist_lock); | |
1531 | ||
1532 | return ret; | |
c4b92fc1 EB |
1533 | } |
1534 | EXPORT_SYMBOL(kill_pgrp); | |
1535 | ||
1536 | int kill_pid(struct pid *pid, int sig, int priv) | |
1537 | { | |
1538 | return kill_pid_info(sig, __si_special(priv), pid); | |
1539 | } | |
1540 | EXPORT_SYMBOL(kill_pid); | |
1541 | ||
1da177e4 LT |
1542 | /* |
1543 | * These functions support sending signals using preallocated sigqueue | |
1544 | * structures. This is needed "because realtime applications cannot | |
1545 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1546 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1547 | * we allocate the sigqueue structure from the timer_create. If this |
1548 | * allocation fails we are able to report the failure to the application | |
1549 | * with an EAGAIN error. | |
1550 | */ | |
1da177e4 LT |
1551 | struct sigqueue *sigqueue_alloc(void) |
1552 | { | |
f84d49b2 | 1553 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1554 | |
f84d49b2 | 1555 | if (q) |
1da177e4 | 1556 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1557 | |
1558 | return q; | |
1da177e4 LT |
1559 | } |
1560 | ||
1561 | void sigqueue_free(struct sigqueue *q) | |
1562 | { | |
1563 | unsigned long flags; | |
60187d27 ON |
1564 | spinlock_t *lock = ¤t->sighand->siglock; |
1565 | ||
1da177e4 LT |
1566 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1567 | /* | |
c8e85b4f ON |
1568 | * We must hold ->siglock while testing q->list |
1569 | * to serialize with collect_signal() or with | |
da7978b0 | 1570 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1571 | */ |
60187d27 | 1572 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1573 | q->flags &= ~SIGQUEUE_PREALLOC; |
1574 | /* | |
1575 | * If it is queued it will be freed when dequeued, | |
1576 | * like the "regular" sigqueue. | |
1577 | */ | |
60187d27 | 1578 | if (!list_empty(&q->list)) |
c8e85b4f | 1579 | q = NULL; |
60187d27 ON |
1580 | spin_unlock_irqrestore(lock, flags); |
1581 | ||
c8e85b4f ON |
1582 | if (q) |
1583 | __sigqueue_free(q); | |
1da177e4 LT |
1584 | } |
1585 | ||
ac5c2153 | 1586 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1587 | { |
e62e6650 | 1588 | int sig = q->info.si_signo; |
2ca3515a | 1589 | struct sigpending *pending; |
e62e6650 | 1590 | unsigned long flags; |
163566f6 | 1591 | int ret, result; |
2ca3515a | 1592 | |
4cd4b6d4 | 1593 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1594 | |
1595 | ret = -1; | |
1596 | if (!likely(lock_task_sighand(t, &flags))) | |
1597 | goto ret; | |
1598 | ||
7e695a5e | 1599 | ret = 1; /* the signal is ignored */ |
163566f6 | 1600 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1601 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1602 | goto out; |
1603 | ||
1604 | ret = 0; | |
9e3bd6c3 PE |
1605 | if (unlikely(!list_empty(&q->list))) { |
1606 | /* | |
1607 | * If an SI_TIMER entry is already queue just increment | |
1608 | * the overrun count. | |
1609 | */ | |
9e3bd6c3 PE |
1610 | BUG_ON(q->info.si_code != SI_TIMER); |
1611 | q->info.si_overrun++; | |
163566f6 | 1612 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1613 | goto out; |
9e3bd6c3 | 1614 | } |
ba661292 | 1615 | q->info.si_overrun = 0; |
9e3bd6c3 | 1616 | |
9e3bd6c3 | 1617 | signalfd_notify(t, sig); |
2ca3515a | 1618 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1619 | list_add_tail(&q->list, &pending->list); |
1620 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1621 | complete_signal(sig, t, group); |
163566f6 | 1622 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1623 | out: |
163566f6 | 1624 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1625 | unlock_task_sighand(t, &flags); |
1626 | ret: | |
1627 | return ret; | |
9e3bd6c3 PE |
1628 | } |
1629 | ||
1da177e4 LT |
1630 | /* |
1631 | * Let a parent know about the death of a child. | |
1632 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1633 | * |
53c8f9f1 ON |
1634 | * Returns true if our parent ignored us and so we've switched to |
1635 | * self-reaping. | |
1da177e4 | 1636 | */ |
53c8f9f1 | 1637 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1638 | { |
1639 | struct siginfo info; | |
1640 | unsigned long flags; | |
1641 | struct sighand_struct *psig; | |
53c8f9f1 | 1642 | bool autoreap = false; |
6fac4829 | 1643 | cputime_t utime, stime; |
1da177e4 LT |
1644 | |
1645 | BUG_ON(sig == -1); | |
1646 | ||
1647 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1648 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1649 | |
d21142ec | 1650 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1651 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1652 | ||
b6e238dc ON |
1653 | if (sig != SIGCHLD) { |
1654 | /* | |
1655 | * This is only possible if parent == real_parent. | |
1656 | * Check if it has changed security domain. | |
1657 | */ | |
1658 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1659 | sig = SIGCHLD; | |
1660 | } | |
1661 | ||
1da177e4 LT |
1662 | info.si_signo = sig; |
1663 | info.si_errno = 0; | |
b488893a | 1664 | /* |
32084504 EB |
1665 | * We are under tasklist_lock here so our parent is tied to |
1666 | * us and cannot change. | |
b488893a | 1667 | * |
32084504 EB |
1668 | * task_active_pid_ns will always return the same pid namespace |
1669 | * until a task passes through release_task. | |
b488893a PE |
1670 | * |
1671 | * write_lock() currently calls preempt_disable() which is the | |
1672 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1673 | * correct to rely on this | |
1674 | */ | |
1675 | rcu_read_lock(); | |
32084504 | 1676 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1677 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1678 | task_uid(tsk)); | |
b488893a PE |
1679 | rcu_read_unlock(); |
1680 | ||
6fac4829 FW |
1681 | task_cputime(tsk, &utime, &stime); |
1682 | info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime); | |
1683 | info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1684 | |
1685 | info.si_status = tsk->exit_code & 0x7f; | |
1686 | if (tsk->exit_code & 0x80) | |
1687 | info.si_code = CLD_DUMPED; | |
1688 | else if (tsk->exit_code & 0x7f) | |
1689 | info.si_code = CLD_KILLED; | |
1690 | else { | |
1691 | info.si_code = CLD_EXITED; | |
1692 | info.si_status = tsk->exit_code >> 8; | |
1693 | } | |
1694 | ||
1695 | psig = tsk->parent->sighand; | |
1696 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1697 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1698 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1699 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1700 | /* | |
1701 | * We are exiting and our parent doesn't care. POSIX.1 | |
1702 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1703 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1704 | * automatically and not left for our parent's wait4 call. | |
1705 | * Rather than having the parent do it as a magic kind of | |
1706 | * signal handler, we just set this to tell do_exit that we | |
1707 | * can be cleaned up without becoming a zombie. Note that | |
1708 | * we still call __wake_up_parent in this case, because a | |
1709 | * blocked sys_wait4 might now return -ECHILD. | |
1710 | * | |
1711 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1712 | * is implementation-defined: we do (if you don't want | |
1713 | * it, just use SIG_IGN instead). | |
1714 | */ | |
53c8f9f1 | 1715 | autoreap = true; |
1da177e4 | 1716 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1717 | sig = 0; |
1da177e4 | 1718 | } |
53c8f9f1 | 1719 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1720 | __group_send_sig_info(sig, &info, tsk->parent); |
1721 | __wake_up_parent(tsk, tsk->parent); | |
1722 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1723 | |
53c8f9f1 | 1724 | return autoreap; |
1da177e4 LT |
1725 | } |
1726 | ||
75b95953 TH |
1727 | /** |
1728 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1729 | * @tsk: task reporting the state change | |
1730 | * @for_ptracer: the notification is for ptracer | |
1731 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1732 | * | |
1733 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1734 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1735 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1736 | * | |
1737 | * CONTEXT: | |
1738 | * Must be called with tasklist_lock at least read locked. | |
1739 | */ | |
1740 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1741 | bool for_ptracer, int why) | |
1da177e4 LT |
1742 | { |
1743 | struct siginfo info; | |
1744 | unsigned long flags; | |
bc505a47 | 1745 | struct task_struct *parent; |
1da177e4 | 1746 | struct sighand_struct *sighand; |
6fac4829 | 1747 | cputime_t utime, stime; |
1da177e4 | 1748 | |
75b95953 | 1749 | if (for_ptracer) { |
bc505a47 | 1750 | parent = tsk->parent; |
75b95953 | 1751 | } else { |
bc505a47 ON |
1752 | tsk = tsk->group_leader; |
1753 | parent = tsk->real_parent; | |
1754 | } | |
1755 | ||
1da177e4 LT |
1756 | info.si_signo = SIGCHLD; |
1757 | info.si_errno = 0; | |
b488893a | 1758 | /* |
5aba085e | 1759 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1760 | */ |
1761 | rcu_read_lock(); | |
17cf22c3 | 1762 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1763 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1764 | rcu_read_unlock(); |
1765 | ||
6fac4829 FW |
1766 | task_cputime(tsk, &utime, &stime); |
1767 | info.si_utime = cputime_to_clock_t(utime); | |
1768 | info.si_stime = cputime_to_clock_t(stime); | |
1da177e4 LT |
1769 | |
1770 | info.si_code = why; | |
1771 | switch (why) { | |
1772 | case CLD_CONTINUED: | |
1773 | info.si_status = SIGCONT; | |
1774 | break; | |
1775 | case CLD_STOPPED: | |
1776 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1777 | break; | |
1778 | case CLD_TRAPPED: | |
1779 | info.si_status = tsk->exit_code & 0x7f; | |
1780 | break; | |
1781 | default: | |
1782 | BUG(); | |
1783 | } | |
1784 | ||
1785 | sighand = parent->sighand; | |
1786 | spin_lock_irqsave(&sighand->siglock, flags); | |
1787 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1788 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1789 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1790 | /* | |
1791 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1792 | */ | |
1793 | __wake_up_parent(tsk, parent); | |
1794 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1795 | } | |
1796 | ||
d5f70c00 ON |
1797 | static inline int may_ptrace_stop(void) |
1798 | { | |
d21142ec | 1799 | if (!likely(current->ptrace)) |
d5f70c00 | 1800 | return 0; |
d5f70c00 ON |
1801 | /* |
1802 | * Are we in the middle of do_coredump? | |
1803 | * If so and our tracer is also part of the coredump stopping | |
1804 | * is a deadlock situation, and pointless because our tracer | |
1805 | * is dead so don't allow us to stop. | |
1806 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1807 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1808 | * is safe to enter schedule(). |
9899d11f ON |
1809 | * |
1810 | * This is almost outdated, a task with the pending SIGKILL can't | |
1811 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1812 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1813 | */ |
999d9fc1 | 1814 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1815 | unlikely(current->mm == current->parent->mm)) |
1816 | return 0; | |
1817 | ||
1818 | return 1; | |
1819 | } | |
1820 | ||
1a669c2f | 1821 | /* |
5aba085e | 1822 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1823 | * Called with the siglock held. |
1824 | */ | |
1825 | static int sigkill_pending(struct task_struct *tsk) | |
1826 | { | |
3d749b9e ON |
1827 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1828 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1829 | } |
1830 | ||
1da177e4 LT |
1831 | /* |
1832 | * This must be called with current->sighand->siglock held. | |
1833 | * | |
1834 | * This should be the path for all ptrace stops. | |
1835 | * We always set current->last_siginfo while stopped here. | |
1836 | * That makes it a way to test a stopped process for | |
1837 | * being ptrace-stopped vs being job-control-stopped. | |
1838 | * | |
20686a30 ON |
1839 | * If we actually decide not to stop at all because the tracer |
1840 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1841 | */ |
fe1bc6a0 | 1842 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1843 | __releases(¤t->sighand->siglock) |
1844 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1845 | { |
ceb6bd67 TH |
1846 | bool gstop_done = false; |
1847 | ||
1a669c2f RM |
1848 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1849 | /* | |
1850 | * The arch code has something special to do before a | |
1851 | * ptrace stop. This is allowed to block, e.g. for faults | |
1852 | * on user stack pages. We can't keep the siglock while | |
1853 | * calling arch_ptrace_stop, so we must release it now. | |
1854 | * To preserve proper semantics, we must do this before | |
1855 | * any signal bookkeeping like checking group_stop_count. | |
1856 | * Meanwhile, a SIGKILL could come in before we retake the | |
1857 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1858 | * So after regaining the lock, we must check for SIGKILL. | |
1859 | */ | |
1860 | spin_unlock_irq(¤t->sighand->siglock); | |
1861 | arch_ptrace_stop(exit_code, info); | |
1862 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1863 | if (sigkill_pending(current)) |
1864 | return; | |
1a669c2f RM |
1865 | } |
1866 | ||
1da177e4 | 1867 | /* |
81be24b8 TH |
1868 | * We're committing to trapping. TRACED should be visible before |
1869 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1870 | * Also, transition to TRACED and updates to ->jobctl should be | |
1871 | * atomic with respect to siglock and should be done after the arch | |
1872 | * hook as siglock is released and regrabbed across it. | |
1da177e4 | 1873 | */ |
81be24b8 | 1874 | set_current_state(TASK_TRACED); |
1da177e4 LT |
1875 | |
1876 | current->last_siginfo = info; | |
1877 | current->exit_code = exit_code; | |
1878 | ||
d79fdd6d | 1879 | /* |
0ae8ce1c TH |
1880 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1881 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1882 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1883 | * could be clear now. We act as if SIGCONT is received after | |
1884 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1885 | */ |
a8f072c1 | 1886 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1887 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1888 | |
fb1d910c | 1889 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1890 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1891 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1892 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1893 | |
81be24b8 | 1894 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1895 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1896 | |
1da177e4 LT |
1897 | spin_unlock_irq(¤t->sighand->siglock); |
1898 | read_lock(&tasklist_lock); | |
3d749b9e | 1899 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1900 | /* |
1901 | * Notify parents of the stop. | |
1902 | * | |
1903 | * While ptraced, there are two parents - the ptracer and | |
1904 | * the real_parent of the group_leader. The ptracer should | |
1905 | * know about every stop while the real parent is only | |
1906 | * interested in the completion of group stop. The states | |
1907 | * for the two don't interact with each other. Notify | |
1908 | * separately unless they're gonna be duplicates. | |
1909 | */ | |
1910 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1911 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1912 | do_notify_parent_cldstop(current, false, why); |
1913 | ||
53da1d94 MS |
1914 | /* |
1915 | * Don't want to allow preemption here, because | |
1916 | * sys_ptrace() needs this task to be inactive. | |
1917 | * | |
1918 | * XXX: implement read_unlock_no_resched(). | |
1919 | */ | |
1920 | preempt_disable(); | |
1da177e4 | 1921 | read_unlock(&tasklist_lock); |
53da1d94 | 1922 | preempt_enable_no_resched(); |
5d8f72b5 | 1923 | freezable_schedule(); |
1da177e4 LT |
1924 | } else { |
1925 | /* | |
1926 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1927 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1928 | * |
1929 | * If @gstop_done, the ptracer went away between group stop | |
1930 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1931 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1932 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1933 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1934 | */ |
ceb6bd67 TH |
1935 | if (gstop_done) |
1936 | do_notify_parent_cldstop(current, false, why); | |
1937 | ||
9899d11f | 1938 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 1939 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1940 | if (clear_code) |
1941 | current->exit_code = 0; | |
6405f7f4 | 1942 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1943 | } |
1944 | ||
1945 | /* | |
1946 | * We are back. Now reacquire the siglock before touching | |
1947 | * last_siginfo, so that we are sure to have synchronized with | |
1948 | * any signal-sending on another CPU that wants to examine it. | |
1949 | */ | |
1950 | spin_lock_irq(¤t->sighand->siglock); | |
1951 | current->last_siginfo = NULL; | |
1952 | ||
544b2c91 TH |
1953 | /* LISTENING can be set only during STOP traps, clear it */ |
1954 | current->jobctl &= ~JOBCTL_LISTENING; | |
1955 | ||
1da177e4 LT |
1956 | /* |
1957 | * Queued signals ignored us while we were stopped for tracing. | |
1958 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1959 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1960 | */ |
b74d0deb | 1961 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1962 | } |
1963 | ||
3544d72a | 1964 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1965 | { |
1966 | siginfo_t info; | |
1967 | ||
1da177e4 | 1968 | memset(&info, 0, sizeof info); |
3544d72a | 1969 | info.si_signo = signr; |
1da177e4 | 1970 | info.si_code = exit_code; |
b488893a | 1971 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1972 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1973 | |
1974 | /* Let the debugger run. */ | |
3544d72a TH |
1975 | ptrace_stop(exit_code, why, 1, &info); |
1976 | } | |
1977 | ||
1978 | void ptrace_notify(int exit_code) | |
1979 | { | |
1980 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
1981 | if (unlikely(current->task_works)) |
1982 | task_work_run(); | |
3544d72a | 1983 | |
1da177e4 | 1984 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1985 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1986 | spin_unlock_irq(¤t->sighand->siglock); |
1987 | } | |
1988 | ||
73ddff2b TH |
1989 | /** |
1990 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1991 | * @signr: signr causing group stop if initiating | |
1992 | * | |
1993 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1994 | * and participate in it. If already set, participate in the existing | |
1995 | * group stop. If participated in a group stop (and thus slept), %true is | |
1996 | * returned with siglock released. | |
1997 | * | |
1998 | * If ptraced, this function doesn't handle stop itself. Instead, | |
1999 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
2000 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
2001 | * places afterwards. | |
2002 | * | |
2003 | * CONTEXT: | |
2004 | * Must be called with @current->sighand->siglock held, which is released | |
2005 | * on %true return. | |
2006 | * | |
2007 | * RETURNS: | |
2008 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
2009 | * %true if participated in group stop. | |
1da177e4 | 2010 | */ |
73ddff2b TH |
2011 | static bool do_signal_stop(int signr) |
2012 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
2013 | { |
2014 | struct signal_struct *sig = current->signal; | |
1da177e4 | 2015 | |
a8f072c1 TH |
2016 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
2017 | unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; | |
f558b7e4 ON |
2018 | struct task_struct *t; |
2019 | ||
a8f072c1 TH |
2020 | /* signr will be recorded in task->jobctl for retries */ |
2021 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 2022 | |
a8f072c1 | 2023 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 2024 | unlikely(signal_group_exit(sig))) |
73ddff2b | 2025 | return false; |
1da177e4 | 2026 | /* |
408a37de TH |
2027 | * There is no group stop already in progress. We must |
2028 | * initiate one now. | |
2029 | * | |
2030 | * While ptraced, a task may be resumed while group stop is | |
2031 | * still in effect and then receive a stop signal and | |
2032 | * initiate another group stop. This deviates from the | |
2033 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2034 | * cause two group stops when !ptraced. That is why we |
2035 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2036 | * |
2037 | * The condition can be distinguished by testing whether | |
2038 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2039 | * group_exit_code in such case. | |
2040 | * | |
2041 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2042 | * an intervening stop signal is required to cause two | |
2043 | * continued events regardless of ptrace. | |
1da177e4 | 2044 | */ |
408a37de TH |
2045 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2046 | sig->group_exit_code = signr; | |
1da177e4 | 2047 | |
7dd3db54 TH |
2048 | sig->group_stop_count = 0; |
2049 | ||
2050 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2051 | sig->group_stop_count++; | |
1da177e4 | 2052 | |
8d38f203 ON |
2053 | t = current; |
2054 | while_each_thread(current, t) { | |
1da177e4 | 2055 | /* |
a122b341 ON |
2056 | * Setting state to TASK_STOPPED for a group |
2057 | * stop is always done with the siglock held, | |
2058 | * so this check has no races. | |
1da177e4 | 2059 | */ |
7dd3db54 TH |
2060 | if (!task_is_stopped(t) && |
2061 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2062 | sig->group_stop_count++; |
fb1d910c TH |
2063 | if (likely(!(t->ptrace & PT_SEIZED))) |
2064 | signal_wake_up(t, 0); | |
2065 | else | |
2066 | ptrace_trap_notify(t); | |
a122b341 | 2067 | } |
d79fdd6d | 2068 | } |
1da177e4 | 2069 | } |
73ddff2b | 2070 | |
d21142ec | 2071 | if (likely(!current->ptrace)) { |
5224fa36 | 2072 | int notify = 0; |
1da177e4 | 2073 | |
5224fa36 TH |
2074 | /* |
2075 | * If there are no other threads in the group, or if there | |
2076 | * is a group stop in progress and we are the last to stop, | |
2077 | * report to the parent. | |
2078 | */ | |
2079 | if (task_participate_group_stop(current)) | |
2080 | notify = CLD_STOPPED; | |
2081 | ||
ae6d2ed7 | 2082 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
2083 | spin_unlock_irq(¤t->sighand->siglock); |
2084 | ||
62bcf9d9 TH |
2085 | /* |
2086 | * Notify the parent of the group stop completion. Because | |
2087 | * we're not holding either the siglock or tasklist_lock | |
2088 | * here, ptracer may attach inbetween; however, this is for | |
2089 | * group stop and should always be delivered to the real | |
2090 | * parent of the group leader. The new ptracer will get | |
2091 | * its notification when this task transitions into | |
2092 | * TASK_TRACED. | |
2093 | */ | |
5224fa36 TH |
2094 | if (notify) { |
2095 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2096 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2097 | read_unlock(&tasklist_lock); |
2098 | } | |
2099 | ||
2100 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
5d8f72b5 | 2101 | freezable_schedule(); |
73ddff2b | 2102 | return true; |
d79fdd6d | 2103 | } else { |
73ddff2b TH |
2104 | /* |
2105 | * While ptraced, group stop is handled by STOP trap. | |
2106 | * Schedule it and let the caller deal with it. | |
2107 | */ | |
2108 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2109 | return false; | |
ae6d2ed7 | 2110 | } |
73ddff2b | 2111 | } |
1da177e4 | 2112 | |
73ddff2b TH |
2113 | /** |
2114 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2115 | * | |
3544d72a TH |
2116 | * When PT_SEIZED, it's used for both group stop and explicit |
2117 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2118 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2119 | * the stop signal; otherwise, %SIGTRAP. | |
2120 | * | |
2121 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2122 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2123 | * |
2124 | * CONTEXT: | |
2125 | * Must be called with @current->sighand->siglock held, which may be | |
2126 | * released and re-acquired before returning with intervening sleep. | |
2127 | */ | |
2128 | static void do_jobctl_trap(void) | |
2129 | { | |
3544d72a | 2130 | struct signal_struct *signal = current->signal; |
73ddff2b | 2131 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2132 | |
3544d72a TH |
2133 | if (current->ptrace & PT_SEIZED) { |
2134 | if (!signal->group_stop_count && | |
2135 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2136 | signr = SIGTRAP; | |
2137 | WARN_ON_ONCE(!signr); | |
2138 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2139 | CLD_STOPPED); | |
2140 | } else { | |
2141 | WARN_ON_ONCE(!signr); | |
2142 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2143 | current->exit_code = 0; | |
ae6d2ed7 | 2144 | } |
1da177e4 LT |
2145 | } |
2146 | ||
94eb22d5 | 2147 | static int ptrace_signal(int signr, siginfo_t *info) |
18c98b65 | 2148 | { |
b7f9591c | 2149 | ptrace_signal_deliver(); |
8a352418 ON |
2150 | /* |
2151 | * We do not check sig_kernel_stop(signr) but set this marker | |
2152 | * unconditionally because we do not know whether debugger will | |
2153 | * change signr. This flag has no meaning unless we are going | |
2154 | * to stop after return from ptrace_stop(). In this case it will | |
2155 | * be checked in do_signal_stop(), we should only stop if it was | |
2156 | * not cleared by SIGCONT while we were sleeping. See also the | |
2157 | * comment in dequeue_signal(). | |
2158 | */ | |
2159 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2160 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2161 | |
2162 | /* We're back. Did the debugger cancel the sig? */ | |
2163 | signr = current->exit_code; | |
2164 | if (signr == 0) | |
2165 | return signr; | |
2166 | ||
2167 | current->exit_code = 0; | |
2168 | ||
5aba085e RD |
2169 | /* |
2170 | * Update the siginfo structure if the signal has | |
2171 | * changed. If the debugger wanted something | |
2172 | * specific in the siginfo structure then it should | |
2173 | * have updated *info via PTRACE_SETSIGINFO. | |
2174 | */ | |
18c98b65 RM |
2175 | if (signr != info->si_signo) { |
2176 | info->si_signo = signr; | |
2177 | info->si_errno = 0; | |
2178 | info->si_code = SI_USER; | |
6b550f94 | 2179 | rcu_read_lock(); |
18c98b65 | 2180 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2181 | info->si_uid = from_kuid_munged(current_user_ns(), |
2182 | task_uid(current->parent)); | |
6b550f94 | 2183 | rcu_read_unlock(); |
18c98b65 RM |
2184 | } |
2185 | ||
2186 | /* If the (new) signal is now blocked, requeue it. */ | |
2187 | if (sigismember(¤t->blocked, signr)) { | |
2188 | specific_send_sig_info(signr, info, current); | |
2189 | signr = 0; | |
2190 | } | |
2191 | ||
2192 | return signr; | |
2193 | } | |
2194 | ||
1da177e4 LT |
2195 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
2196 | struct pt_regs *regs, void *cookie) | |
2197 | { | |
f6b76d4f ON |
2198 | struct sighand_struct *sighand = current->sighand; |
2199 | struct signal_struct *signal = current->signal; | |
2200 | int signr; | |
1da177e4 | 2201 | |
f784e8a7 ON |
2202 | if (unlikely(current->task_works)) |
2203 | task_work_run(); | |
72667028 | 2204 | |
0326f5a9 SD |
2205 | if (unlikely(uprobe_deny_signal())) |
2206 | return 0; | |
2207 | ||
13b1c3d4 | 2208 | /* |
5d8f72b5 ON |
2209 | * Do this once, we can't return to user-mode if freezing() == T. |
2210 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2211 | * thus do not need another check after return. | |
13b1c3d4 | 2212 | */ |
fc558a74 RW |
2213 | try_to_freeze(); |
2214 | ||
5d8f72b5 | 2215 | relock: |
f6b76d4f | 2216 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2217 | /* |
2218 | * Every stopped thread goes here after wakeup. Check to see if | |
2219 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2220 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2221 | */ | |
f6b76d4f | 2222 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2223 | int why; |
2224 | ||
2225 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2226 | why = CLD_CONTINUED; | |
2227 | else | |
2228 | why = CLD_STOPPED; | |
2229 | ||
f6b76d4f | 2230 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2231 | |
ae6d2ed7 | 2232 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2233 | |
ceb6bd67 TH |
2234 | /* |
2235 | * Notify the parent that we're continuing. This event is | |
2236 | * always per-process and doesn't make whole lot of sense | |
2237 | * for ptracers, who shouldn't consume the state via | |
2238 | * wait(2) either, but, for backward compatibility, notify | |
2239 | * the ptracer of the group leader too unless it's gonna be | |
2240 | * a duplicate. | |
2241 | */ | |
edf2ed15 | 2242 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2243 | do_notify_parent_cldstop(current, false, why); |
2244 | ||
bb3696da ON |
2245 | if (ptrace_reparented(current->group_leader)) |
2246 | do_notify_parent_cldstop(current->group_leader, | |
2247 | true, why); | |
edf2ed15 | 2248 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2249 | |
e4420551 ON |
2250 | goto relock; |
2251 | } | |
2252 | ||
1da177e4 LT |
2253 | for (;;) { |
2254 | struct k_sigaction *ka; | |
1be53963 | 2255 | |
dd1d6772 TH |
2256 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2257 | do_signal_stop(0)) | |
7bcf6a2c | 2258 | goto relock; |
1be53963 | 2259 | |
73ddff2b TH |
2260 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2261 | do_jobctl_trap(); | |
2262 | spin_unlock_irq(&sighand->siglock); | |
2263 | goto relock; | |
2264 | } | |
1da177e4 | 2265 | |
dd1d6772 | 2266 | signr = dequeue_signal(current, ¤t->blocked, info); |
7bcf6a2c | 2267 | |
dd1d6772 TH |
2268 | if (!signr) |
2269 | break; /* will return 0 */ | |
7bcf6a2c | 2270 | |
8a352418 | 2271 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
94eb22d5 | 2272 | signr = ptrace_signal(signr, info); |
dd1d6772 TH |
2273 | if (!signr) |
2274 | continue; | |
1da177e4 LT |
2275 | } |
2276 | ||
dd1d6772 TH |
2277 | ka = &sighand->action[signr-1]; |
2278 | ||
f9d4257e MH |
2279 | /* Trace actually delivered signals. */ |
2280 | trace_signal_deliver(signr, info, ka); | |
2281 | ||
1da177e4 LT |
2282 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2283 | continue; | |
2284 | if (ka->sa.sa_handler != SIG_DFL) { | |
2285 | /* Run the handler. */ | |
2286 | *return_ka = *ka; | |
2287 | ||
2288 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2289 | ka->sa.sa_handler = SIG_DFL; | |
2290 | ||
2291 | break; /* will return non-zero "signr" value */ | |
2292 | } | |
2293 | ||
2294 | /* | |
2295 | * Now we are doing the default action for this signal. | |
2296 | */ | |
2297 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2298 | continue; | |
2299 | ||
84d73786 | 2300 | /* |
0fbc26a6 | 2301 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2302 | * Container-init gets no signals it doesn't want from same |
2303 | * container. | |
2304 | * | |
2305 | * Note that if global/container-init sees a sig_kernel_only() | |
2306 | * signal here, the signal must have been generated internally | |
2307 | * or must have come from an ancestor namespace. In either | |
2308 | * case, the signal cannot be dropped. | |
84d73786 | 2309 | */ |
fae5fa44 | 2310 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2311 | !sig_kernel_only(signr)) |
1da177e4 LT |
2312 | continue; |
2313 | ||
2314 | if (sig_kernel_stop(signr)) { | |
2315 | /* | |
2316 | * The default action is to stop all threads in | |
2317 | * the thread group. The job control signals | |
2318 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2319 | * always works. Note that siglock needs to be | |
2320 | * dropped during the call to is_orphaned_pgrp() | |
2321 | * because of lock ordering with tasklist_lock. | |
2322 | * This allows an intervening SIGCONT to be posted. | |
2323 | * We need to check for that and bail out if necessary. | |
2324 | */ | |
2325 | if (signr != SIGSTOP) { | |
f6b76d4f | 2326 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2327 | |
2328 | /* signals can be posted during this window */ | |
2329 | ||
3e7cd6c4 | 2330 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2331 | goto relock; |
2332 | ||
f6b76d4f | 2333 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2334 | } |
2335 | ||
7bcf6a2c | 2336 | if (likely(do_signal_stop(info->si_signo))) { |
1da177e4 LT |
2337 | /* It released the siglock. */ |
2338 | goto relock; | |
2339 | } | |
2340 | ||
2341 | /* | |
2342 | * We didn't actually stop, due to a race | |
2343 | * with SIGCONT or something like that. | |
2344 | */ | |
2345 | continue; | |
2346 | } | |
2347 | ||
f6b76d4f | 2348 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2349 | |
2350 | /* | |
2351 | * Anything else is fatal, maybe with a core dump. | |
2352 | */ | |
2353 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2354 | |
1da177e4 | 2355 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2356 | if (print_fatal_signals) |
4aaefee5 | 2357 | print_fatal_signal(info->si_signo); |
2b5faa4c | 2358 | proc_coredump_connector(current); |
1da177e4 LT |
2359 | /* |
2360 | * If it was able to dump core, this kills all | |
2361 | * other threads in the group and synchronizes with | |
2362 | * their demise. If we lost the race with another | |
2363 | * thread getting here, it set group_exit_code | |
2364 | * first and our do_group_exit call below will use | |
2365 | * that value and ignore the one we pass it. | |
2366 | */ | |
541880d9 | 2367 | do_coredump(info); |
1da177e4 LT |
2368 | } |
2369 | ||
2370 | /* | |
2371 | * Death signals, no core dump. | |
2372 | */ | |
7bcf6a2c | 2373 | do_group_exit(info->si_signo); |
1da177e4 LT |
2374 | /* NOTREACHED */ |
2375 | } | |
f6b76d4f | 2376 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2377 | return signr; |
2378 | } | |
2379 | ||
5e6292c0 | 2380 | /** |
efee984c AV |
2381 | * signal_delivered - |
2382 | * @sig: number of signal being delivered | |
2383 | * @info: siginfo_t of signal being delivered | |
2384 | * @ka: sigaction setting that chose the handler | |
2385 | * @regs: user register state | |
2386 | * @stepping: nonzero if debugger single-step or block-step in use | |
5e6292c0 | 2387 | * |
e227867f | 2388 | * This function should be called when a signal has successfully been |
efee984c AV |
2389 | * delivered. It updates the blocked signals accordingly (@ka->sa.sa_mask |
2390 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER | |
2391 | * is set in @ka->sa.sa_flags. Tracing is notified. | |
5e6292c0 | 2392 | */ |
efee984c AV |
2393 | void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka, |
2394 | struct pt_regs *regs, int stepping) | |
5e6292c0 MF |
2395 | { |
2396 | sigset_t blocked; | |
2397 | ||
a610d6e6 AV |
2398 | /* A signal was successfully delivered, and the |
2399 | saved sigmask was stored on the signal frame, | |
2400 | and will be restored by sigreturn. So we can | |
2401 | simply clear the restore sigmask flag. */ | |
2402 | clear_restore_sigmask(); | |
2403 | ||
5e6292c0 MF |
2404 | sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask); |
2405 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
efee984c | 2406 | sigaddset(&blocked, sig); |
5e6292c0 | 2407 | set_current_blocked(&blocked); |
efee984c | 2408 | tracehook_signal_handler(sig, info, ka, regs, stepping); |
5e6292c0 MF |
2409 | } |
2410 | ||
2ce5da17 AV |
2411 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2412 | { | |
2413 | if (failed) | |
2414 | force_sigsegv(ksig->sig, current); | |
2415 | else | |
2416 | signal_delivered(ksig->sig, &ksig->info, &ksig->ka, | |
2417 | signal_pt_regs(), stepping); | |
2418 | } | |
2419 | ||
0edceb7b ON |
2420 | /* |
2421 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2422 | * group-wide signal. Other threads should be notified now to take |
2423 | * the shared signals in @which since we will not. | |
0edceb7b | 2424 | */ |
f646e227 | 2425 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2426 | { |
f646e227 | 2427 | sigset_t retarget; |
0edceb7b ON |
2428 | struct task_struct *t; |
2429 | ||
f646e227 ON |
2430 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2431 | if (sigisemptyset(&retarget)) | |
2432 | return; | |
2433 | ||
0edceb7b ON |
2434 | t = tsk; |
2435 | while_each_thread(tsk, t) { | |
fec9993d ON |
2436 | if (t->flags & PF_EXITING) |
2437 | continue; | |
2438 | ||
2439 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2440 | continue; | |
2441 | /* Remove the signals this thread can handle. */ | |
2442 | sigandsets(&retarget, &retarget, &t->blocked); | |
2443 | ||
2444 | if (!signal_pending(t)) | |
2445 | signal_wake_up(t, 0); | |
2446 | ||
2447 | if (sigisemptyset(&retarget)) | |
2448 | break; | |
0edceb7b ON |
2449 | } |
2450 | } | |
2451 | ||
d12619b5 ON |
2452 | void exit_signals(struct task_struct *tsk) |
2453 | { | |
2454 | int group_stop = 0; | |
f646e227 | 2455 | sigset_t unblocked; |
d12619b5 | 2456 | |
77e4ef99 TH |
2457 | /* |
2458 | * @tsk is about to have PF_EXITING set - lock out users which | |
2459 | * expect stable threadgroup. | |
2460 | */ | |
2461 | threadgroup_change_begin(tsk); | |
2462 | ||
5dee1707 ON |
2463 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2464 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2465 | threadgroup_change_end(tsk); |
5dee1707 | 2466 | return; |
d12619b5 ON |
2467 | } |
2468 | ||
5dee1707 | 2469 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2470 | /* |
2471 | * From now this task is not visible for group-wide signals, | |
2472 | * see wants_signal(), do_signal_stop(). | |
2473 | */ | |
2474 | tsk->flags |= PF_EXITING; | |
77e4ef99 TH |
2475 | |
2476 | threadgroup_change_end(tsk); | |
2477 | ||
5dee1707 ON |
2478 | if (!signal_pending(tsk)) |
2479 | goto out; | |
2480 | ||
f646e227 ON |
2481 | unblocked = tsk->blocked; |
2482 | signotset(&unblocked); | |
2483 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2484 | |
a8f072c1 | 2485 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2486 | task_participate_group_stop(tsk)) |
edf2ed15 | 2487 | group_stop = CLD_STOPPED; |
5dee1707 | 2488 | out: |
d12619b5 ON |
2489 | spin_unlock_irq(&tsk->sighand->siglock); |
2490 | ||
62bcf9d9 TH |
2491 | /* |
2492 | * If group stop has completed, deliver the notification. This | |
2493 | * should always go to the real parent of the group leader. | |
2494 | */ | |
ae6d2ed7 | 2495 | if (unlikely(group_stop)) { |
d12619b5 | 2496 | read_lock(&tasklist_lock); |
62bcf9d9 | 2497 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2498 | read_unlock(&tasklist_lock); |
2499 | } | |
2500 | } | |
2501 | ||
1da177e4 LT |
2502 | EXPORT_SYMBOL(recalc_sigpending); |
2503 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2504 | EXPORT_SYMBOL(flush_signals); | |
2505 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2506 | EXPORT_SYMBOL(send_sig); |
2507 | EXPORT_SYMBOL(send_sig_info); | |
2508 | EXPORT_SYMBOL(sigprocmask); | |
2509 | EXPORT_SYMBOL(block_all_signals); | |
2510 | EXPORT_SYMBOL(unblock_all_signals); | |
2511 | ||
2512 | ||
2513 | /* | |
2514 | * System call entry points. | |
2515 | */ | |
2516 | ||
41c57892 RD |
2517 | /** |
2518 | * sys_restart_syscall - restart a system call | |
2519 | */ | |
754fe8d2 | 2520 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 LT |
2521 | { |
2522 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
2523 | return restart->fn(restart); | |
2524 | } | |
2525 | ||
2526 | long do_no_restart_syscall(struct restart_block *param) | |
2527 | { | |
2528 | return -EINTR; | |
2529 | } | |
2530 | ||
b182801a ON |
2531 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2532 | { | |
2533 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2534 | sigset_t newblocked; | |
2535 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2536 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2537 | retarget_shared_pending(tsk, &newblocked); |
2538 | } | |
2539 | tsk->blocked = *newset; | |
2540 | recalc_sigpending(); | |
2541 | } | |
2542 | ||
e6fa16ab ON |
2543 | /** |
2544 | * set_current_blocked - change current->blocked mask | |
2545 | * @newset: new mask | |
2546 | * | |
2547 | * It is wrong to change ->blocked directly, this helper should be used | |
2548 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2549 | */ |
77097ae5 AV |
2550 | void set_current_blocked(sigset_t *newset) |
2551 | { | |
77097ae5 | 2552 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2553 | __set_current_blocked(newset); |
77097ae5 AV |
2554 | } |
2555 | ||
2556 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2557 | { |
2558 | struct task_struct *tsk = current; | |
2559 | ||
2560 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2561 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2562 | spin_unlock_irq(&tsk->sighand->siglock); |
2563 | } | |
1da177e4 LT |
2564 | |
2565 | /* | |
2566 | * This is also useful for kernel threads that want to temporarily | |
2567 | * (or permanently) block certain signals. | |
2568 | * | |
2569 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2570 | * interface happily blocks "unblockable" signals like SIGKILL | |
2571 | * and friends. | |
2572 | */ | |
2573 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2574 | { | |
73ef4aeb ON |
2575 | struct task_struct *tsk = current; |
2576 | sigset_t newset; | |
1da177e4 | 2577 | |
73ef4aeb | 2578 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2579 | if (oldset) |
73ef4aeb | 2580 | *oldset = tsk->blocked; |
a26fd335 | 2581 | |
1da177e4 LT |
2582 | switch (how) { |
2583 | case SIG_BLOCK: | |
73ef4aeb | 2584 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2585 | break; |
2586 | case SIG_UNBLOCK: | |
702a5073 | 2587 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2588 | break; |
2589 | case SIG_SETMASK: | |
73ef4aeb | 2590 | newset = *set; |
1da177e4 LT |
2591 | break; |
2592 | default: | |
73ef4aeb | 2593 | return -EINVAL; |
1da177e4 | 2594 | } |
a26fd335 | 2595 | |
77097ae5 | 2596 | __set_current_blocked(&newset); |
73ef4aeb | 2597 | return 0; |
1da177e4 LT |
2598 | } |
2599 | ||
41c57892 RD |
2600 | /** |
2601 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2602 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2603 | * @nset: stores pending signals |
41c57892 RD |
2604 | * @oset: previous value of signal mask if non-null |
2605 | * @sigsetsize: size of sigset_t type | |
2606 | */ | |
bb7efee2 | 2607 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2608 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2609 | { |
1da177e4 | 2610 | sigset_t old_set, new_set; |
bb7efee2 | 2611 | int error; |
1da177e4 LT |
2612 | |
2613 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2614 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2615 | return -EINVAL; |
1da177e4 | 2616 | |
bb7efee2 ON |
2617 | old_set = current->blocked; |
2618 | ||
2619 | if (nset) { | |
2620 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2621 | return -EFAULT; | |
1da177e4 LT |
2622 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2623 | ||
bb7efee2 | 2624 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2625 | if (error) |
bb7efee2 ON |
2626 | return error; |
2627 | } | |
1da177e4 | 2628 | |
bb7efee2 ON |
2629 | if (oset) { |
2630 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2631 | return -EFAULT; | |
1da177e4 | 2632 | } |
bb7efee2 ON |
2633 | |
2634 | return 0; | |
1da177e4 LT |
2635 | } |
2636 | ||
322a56cb | 2637 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2638 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2639 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2640 | { |
322a56cb AV |
2641 | #ifdef __BIG_ENDIAN |
2642 | sigset_t old_set = current->blocked; | |
2643 | ||
2644 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2645 | if (sigsetsize != sizeof(sigset_t)) | |
2646 | return -EINVAL; | |
2647 | ||
2648 | if (nset) { | |
2649 | compat_sigset_t new32; | |
2650 | sigset_t new_set; | |
2651 | int error; | |
2652 | if (copy_from_user(&new32, nset, sizeof(compat_sigset_t))) | |
2653 | return -EFAULT; | |
2654 | ||
2655 | sigset_from_compat(&new_set, &new32); | |
2656 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2657 | ||
2658 | error = sigprocmask(how, &new_set, NULL); | |
2659 | if (error) | |
2660 | return error; | |
2661 | } | |
2662 | if (oset) { | |
2663 | compat_sigset_t old32; | |
2664 | sigset_to_compat(&old32, &old_set); | |
db61ec29 | 2665 | if (copy_to_user(oset, &old32, sizeof(compat_sigset_t))) |
322a56cb AV |
2666 | return -EFAULT; |
2667 | } | |
2668 | return 0; | |
2669 | #else | |
2670 | return sys_rt_sigprocmask(how, (sigset_t __user *)nset, | |
2671 | (sigset_t __user *)oset, sigsetsize); | |
2672 | #endif | |
2673 | } | |
2674 | #endif | |
1da177e4 | 2675 | |
fe9c1db2 | 2676 | static int do_sigpending(void *set, unsigned long sigsetsize) |
1da177e4 | 2677 | { |
1da177e4 | 2678 | if (sigsetsize > sizeof(sigset_t)) |
fe9c1db2 | 2679 | return -EINVAL; |
1da177e4 LT |
2680 | |
2681 | spin_lock_irq(¤t->sighand->siglock); | |
fe9c1db2 | 2682 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
2683 | ¤t->signal->shared_pending.signal); |
2684 | spin_unlock_irq(¤t->sighand->siglock); | |
2685 | ||
2686 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 AV |
2687 | sigandsets(set, ¤t->blocked, set); |
2688 | return 0; | |
5aba085e | 2689 | } |
1da177e4 | 2690 | |
41c57892 RD |
2691 | /** |
2692 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2693 | * while blocked | |
20f22ab4 | 2694 | * @uset: stores pending signals |
41c57892 RD |
2695 | * @sigsetsize: size of sigset_t type or larger |
2696 | */ | |
fe9c1db2 | 2697 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 2698 | { |
fe9c1db2 AV |
2699 | sigset_t set; |
2700 | int err = do_sigpending(&set, sigsetsize); | |
2701 | if (!err && copy_to_user(uset, &set, sigsetsize)) | |
2702 | err = -EFAULT; | |
2703 | return err; | |
2704 | } | |
2705 | ||
2706 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
2707 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
2708 | compat_size_t, sigsetsize) | |
1da177e4 | 2709 | { |
fe9c1db2 AV |
2710 | #ifdef __BIG_ENDIAN |
2711 | sigset_t set; | |
2712 | int err = do_sigpending(&set, sigsetsize); | |
2713 | if (!err) { | |
2714 | compat_sigset_t set32; | |
2715 | sigset_to_compat(&set32, &set); | |
2716 | /* we can get here only if sigsetsize <= sizeof(set) */ | |
2717 | if (copy_to_user(uset, &set32, sigsetsize)) | |
2718 | err = -EFAULT; | |
2719 | } | |
2720 | return err; | |
2721 | #else | |
2722 | return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize); | |
2723 | #endif | |
1da177e4 | 2724 | } |
fe9c1db2 | 2725 | #endif |
1da177e4 LT |
2726 | |
2727 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2728 | ||
ce395960 | 2729 | int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) |
1da177e4 LT |
2730 | { |
2731 | int err; | |
2732 | ||
2733 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2734 | return -EFAULT; | |
2735 | if (from->si_code < 0) | |
2736 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2737 | ? -EFAULT : 0; | |
2738 | /* | |
2739 | * If you change siginfo_t structure, please be sure | |
2740 | * this code is fixed accordingly. | |
fba2afaa DL |
2741 | * Please remember to update the signalfd_copyinfo() function |
2742 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2743 | * It should never copy any pad contained in the structure |
2744 | * to avoid security leaks, but must copy the generic | |
2745 | * 3 ints plus the relevant union member. | |
2746 | */ | |
2747 | err = __put_user(from->si_signo, &to->si_signo); | |
2748 | err |= __put_user(from->si_errno, &to->si_errno); | |
2749 | err |= __put_user((short)from->si_code, &to->si_code); | |
2750 | switch (from->si_code & __SI_MASK) { | |
2751 | case __SI_KILL: | |
2752 | err |= __put_user(from->si_pid, &to->si_pid); | |
2753 | err |= __put_user(from->si_uid, &to->si_uid); | |
2754 | break; | |
2755 | case __SI_TIMER: | |
2756 | err |= __put_user(from->si_tid, &to->si_tid); | |
2757 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2758 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2759 | break; | |
2760 | case __SI_POLL: | |
2761 | err |= __put_user(from->si_band, &to->si_band); | |
2762 | err |= __put_user(from->si_fd, &to->si_fd); | |
2763 | break; | |
2764 | case __SI_FAULT: | |
2765 | err |= __put_user(from->si_addr, &to->si_addr); | |
2766 | #ifdef __ARCH_SI_TRAPNO | |
2767 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2768 | #endif |
2769 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2770 | /* |
a337fdac | 2771 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2772 | * so check explicitly for the right codes here. |
a337fdac AK |
2773 | */ |
2774 | if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) | |
2775 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); | |
1da177e4 LT |
2776 | #endif |
2777 | break; | |
2778 | case __SI_CHLD: | |
2779 | err |= __put_user(from->si_pid, &to->si_pid); | |
2780 | err |= __put_user(from->si_uid, &to->si_uid); | |
2781 | err |= __put_user(from->si_status, &to->si_status); | |
2782 | err |= __put_user(from->si_utime, &to->si_utime); | |
2783 | err |= __put_user(from->si_stime, &to->si_stime); | |
2784 | break; | |
2785 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2786 | case __SI_MESGQ: /* But this is */ | |
2787 | err |= __put_user(from->si_pid, &to->si_pid); | |
2788 | err |= __put_user(from->si_uid, &to->si_uid); | |
2789 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2790 | break; | |
a0727e8c WD |
2791 | #ifdef __ARCH_SIGSYS |
2792 | case __SI_SYS: | |
2793 | err |= __put_user(from->si_call_addr, &to->si_call_addr); | |
2794 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2795 | err |= __put_user(from->si_arch, &to->si_arch); | |
2796 | break; | |
2797 | #endif | |
1da177e4 LT |
2798 | default: /* this is just in case for now ... */ |
2799 | err |= __put_user(from->si_pid, &to->si_pid); | |
2800 | err |= __put_user(from->si_uid, &to->si_uid); | |
2801 | break; | |
2802 | } | |
2803 | return err; | |
2804 | } | |
2805 | ||
2806 | #endif | |
2807 | ||
943df148 ON |
2808 | /** |
2809 | * do_sigtimedwait - wait for queued signals specified in @which | |
2810 | * @which: queued signals to wait for | |
2811 | * @info: if non-null, the signal's siginfo is returned here | |
2812 | * @ts: upper bound on process time suspension | |
2813 | */ | |
2814 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info, | |
2815 | const struct timespec *ts) | |
2816 | { | |
2817 | struct task_struct *tsk = current; | |
2818 | long timeout = MAX_SCHEDULE_TIMEOUT; | |
2819 | sigset_t mask = *which; | |
2820 | int sig; | |
2821 | ||
2822 | if (ts) { | |
2823 | if (!timespec_valid(ts)) | |
2824 | return -EINVAL; | |
2825 | timeout = timespec_to_jiffies(ts); | |
2826 | /* | |
2827 | * We can be close to the next tick, add another one | |
2828 | * to ensure we will wait at least the time asked for. | |
2829 | */ | |
2830 | if (ts->tv_sec || ts->tv_nsec) | |
2831 | timeout++; | |
2832 | } | |
2833 | ||
2834 | /* | |
2835 | * Invert the set of allowed signals to get those we want to block. | |
2836 | */ | |
2837 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2838 | signotset(&mask); | |
2839 | ||
2840 | spin_lock_irq(&tsk->sighand->siglock); | |
2841 | sig = dequeue_signal(tsk, &mask, info); | |
2842 | if (!sig && timeout) { | |
2843 | /* | |
2844 | * None ready, temporarily unblock those we're interested | |
2845 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2846 | * they arrive. Unblocking is always fine, we can avoid |
2847 | * set_current_blocked(). | |
943df148 ON |
2848 | */ |
2849 | tsk->real_blocked = tsk->blocked; | |
2850 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2851 | recalc_sigpending(); | |
2852 | spin_unlock_irq(&tsk->sighand->siglock); | |
2853 | ||
a2d5f1f5 | 2854 | timeout = freezable_schedule_timeout_interruptible(timeout); |
943df148 ON |
2855 | |
2856 | spin_lock_irq(&tsk->sighand->siglock); | |
b182801a | 2857 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 2858 | sigemptyset(&tsk->real_blocked); |
b182801a | 2859 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2860 | } |
2861 | spin_unlock_irq(&tsk->sighand->siglock); | |
2862 | ||
2863 | if (sig) | |
2864 | return sig; | |
2865 | return timeout ? -EINTR : -EAGAIN; | |
2866 | } | |
2867 | ||
41c57892 RD |
2868 | /** |
2869 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2870 | * in @uthese | |
2871 | * @uthese: queued signals to wait for | |
2872 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2873 | * @uts: upper bound on process time suspension | |
2874 | * @sigsetsize: size of sigset_t type | |
2875 | */ | |
17da2bd9 HC |
2876 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2877 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2878 | size_t, sigsetsize) | |
1da177e4 | 2879 | { |
1da177e4 LT |
2880 | sigset_t these; |
2881 | struct timespec ts; | |
2882 | siginfo_t info; | |
943df148 | 2883 | int ret; |
1da177e4 LT |
2884 | |
2885 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2886 | if (sigsetsize != sizeof(sigset_t)) | |
2887 | return -EINVAL; | |
2888 | ||
2889 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2890 | return -EFAULT; | |
5aba085e | 2891 | |
1da177e4 LT |
2892 | if (uts) { |
2893 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2894 | return -EFAULT; | |
1da177e4 LT |
2895 | } |
2896 | ||
943df148 | 2897 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2898 | |
943df148 ON |
2899 | if (ret > 0 && uinfo) { |
2900 | if (copy_siginfo_to_user(uinfo, &info)) | |
2901 | ret = -EFAULT; | |
1da177e4 LT |
2902 | } |
2903 | ||
2904 | return ret; | |
2905 | } | |
2906 | ||
41c57892 RD |
2907 | /** |
2908 | * sys_kill - send a signal to a process | |
2909 | * @pid: the PID of the process | |
2910 | * @sig: signal to be sent | |
2911 | */ | |
17da2bd9 | 2912 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2913 | { |
2914 | struct siginfo info; | |
2915 | ||
2916 | info.si_signo = sig; | |
2917 | info.si_errno = 0; | |
2918 | info.si_code = SI_USER; | |
b488893a | 2919 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2920 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2921 | |
2922 | return kill_something_info(sig, &info, pid); | |
2923 | } | |
2924 | ||
30b4ae8a TG |
2925 | static int |
2926 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2927 | { |
1da177e4 | 2928 | struct task_struct *p; |
30b4ae8a | 2929 | int error = -ESRCH; |
1da177e4 | 2930 | |
3547ff3a | 2931 | rcu_read_lock(); |
228ebcbe | 2932 | p = find_task_by_vpid(pid); |
b488893a | 2933 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2934 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2935 | /* |
2936 | * The null signal is a permissions and process existence | |
2937 | * probe. No signal is actually delivered. | |
2938 | */ | |
4a30debf ON |
2939 | if (!error && sig) { |
2940 | error = do_send_sig_info(sig, info, p, false); | |
2941 | /* | |
2942 | * If lock_task_sighand() failed we pretend the task | |
2943 | * dies after receiving the signal. The window is tiny, | |
2944 | * and the signal is private anyway. | |
2945 | */ | |
2946 | if (unlikely(error == -ESRCH)) | |
2947 | error = 0; | |
1da177e4 LT |
2948 | } |
2949 | } | |
3547ff3a | 2950 | rcu_read_unlock(); |
6dd69f10 | 2951 | |
1da177e4 LT |
2952 | return error; |
2953 | } | |
2954 | ||
30b4ae8a TG |
2955 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2956 | { | |
b9e146d8 | 2957 | struct siginfo info = {}; |
30b4ae8a TG |
2958 | |
2959 | info.si_signo = sig; | |
2960 | info.si_errno = 0; | |
2961 | info.si_code = SI_TKILL; | |
2962 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 2963 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
2964 | |
2965 | return do_send_specific(tgid, pid, sig, &info); | |
2966 | } | |
2967 | ||
6dd69f10 VL |
2968 | /** |
2969 | * sys_tgkill - send signal to one specific thread | |
2970 | * @tgid: the thread group ID of the thread | |
2971 | * @pid: the PID of the thread | |
2972 | * @sig: signal to be sent | |
2973 | * | |
72fd4a35 | 2974 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2975 | * exists but it's not belonging to the target process anymore. This |
2976 | * method solves the problem of threads exiting and PIDs getting reused. | |
2977 | */ | |
a5f8fa9e | 2978 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2979 | { |
2980 | /* This is only valid for single tasks */ | |
2981 | if (pid <= 0 || tgid <= 0) | |
2982 | return -EINVAL; | |
2983 | ||
2984 | return do_tkill(tgid, pid, sig); | |
2985 | } | |
2986 | ||
41c57892 RD |
2987 | /** |
2988 | * sys_tkill - send signal to one specific task | |
2989 | * @pid: the PID of the task | |
2990 | * @sig: signal to be sent | |
2991 | * | |
1da177e4 LT |
2992 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2993 | */ | |
a5f8fa9e | 2994 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2995 | { |
1da177e4 LT |
2996 | /* This is only valid for single tasks */ |
2997 | if (pid <= 0) | |
2998 | return -EINVAL; | |
2999 | ||
6dd69f10 | 3000 | return do_tkill(0, pid, sig); |
1da177e4 LT |
3001 | } |
3002 | ||
75907d4d AV |
3003 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) |
3004 | { | |
3005 | /* Not even root can pretend to send signals from the kernel. | |
3006 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
3007 | */ | |
66dd34ad AV |
3008 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3009 | (task_pid_vnr(current) != pid)) { | |
75907d4d AV |
3010 | /* We used to allow any < 0 si_code */ |
3011 | WARN_ON_ONCE(info->si_code < 0); | |
3012 | return -EPERM; | |
3013 | } | |
3014 | info->si_signo = sig; | |
3015 | ||
3016 | /* POSIX.1b doesn't mention process groups. */ | |
3017 | return kill_proc_info(sig, info, pid); | |
3018 | } | |
3019 | ||
41c57892 RD |
3020 | /** |
3021 | * sys_rt_sigqueueinfo - send signal information to a signal | |
3022 | * @pid: the PID of the thread | |
3023 | * @sig: signal to be sent | |
3024 | * @uinfo: signal info to be sent | |
3025 | */ | |
a5f8fa9e HC |
3026 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
3027 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
3028 | { |
3029 | siginfo_t info; | |
1da177e4 LT |
3030 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) |
3031 | return -EFAULT; | |
75907d4d AV |
3032 | return do_rt_sigqueueinfo(pid, sig, &info); |
3033 | } | |
1da177e4 | 3034 | |
75907d4d | 3035 | #ifdef CONFIG_COMPAT |
75907d4d AV |
3036 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
3037 | compat_pid_t, pid, | |
3038 | int, sig, | |
3039 | struct compat_siginfo __user *, uinfo) | |
3040 | { | |
3041 | siginfo_t info; | |
3042 | int ret = copy_siginfo_from_user32(&info, uinfo); | |
3043 | if (unlikely(ret)) | |
3044 | return ret; | |
3045 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 3046 | } |
75907d4d | 3047 | #endif |
1da177e4 | 3048 | |
9aae8fc0 | 3049 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
62ab4505 TG |
3050 | { |
3051 | /* This is only valid for single tasks */ | |
3052 | if (pid <= 0 || tgid <= 0) | |
3053 | return -EINVAL; | |
3054 | ||
3055 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3056 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3057 | */ | |
66dd34ad AV |
3058 | if (((info->si_code >= 0 || info->si_code == SI_TKILL)) && |
3059 | (task_pid_vnr(current) != pid)) { | |
da48524e JT |
3060 | /* We used to allow any < 0 si_code */ |
3061 | WARN_ON_ONCE(info->si_code < 0); | |
62ab4505 | 3062 | return -EPERM; |
da48524e | 3063 | } |
62ab4505 TG |
3064 | info->si_signo = sig; |
3065 | ||
3066 | return do_send_specific(tgid, pid, sig, info); | |
3067 | } | |
3068 | ||
3069 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3070 | siginfo_t __user *, uinfo) | |
3071 | { | |
3072 | siginfo_t info; | |
3073 | ||
3074 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3075 | return -EFAULT; | |
3076 | ||
3077 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3078 | } | |
3079 | ||
9aae8fc0 AV |
3080 | #ifdef CONFIG_COMPAT |
3081 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3082 | compat_pid_t, tgid, | |
3083 | compat_pid_t, pid, | |
3084 | int, sig, | |
3085 | struct compat_siginfo __user *, uinfo) | |
3086 | { | |
3087 | siginfo_t info; | |
3088 | ||
3089 | if (copy_siginfo_from_user32(&info, uinfo)) | |
3090 | return -EFAULT; | |
3091 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3092 | } | |
3093 | #endif | |
3094 | ||
88531f72 | 3095 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3096 | { |
93585eea | 3097 | struct task_struct *t = current; |
1da177e4 | 3098 | struct k_sigaction *k; |
71fabd5e | 3099 | sigset_t mask; |
1da177e4 | 3100 | |
7ed20e1a | 3101 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3102 | return -EINVAL; |
3103 | ||
93585eea | 3104 | k = &t->sighand->action[sig-1]; |
1da177e4 LT |
3105 | |
3106 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
3107 | if (oact) |
3108 | *oact = *k; | |
3109 | ||
3110 | if (act) { | |
9ac95f2f ON |
3111 | sigdelsetmask(&act->sa.sa_mask, |
3112 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3113 | *k = *act; |
1da177e4 LT |
3114 | /* |
3115 | * POSIX 3.3.1.3: | |
3116 | * "Setting a signal action to SIG_IGN for a signal that is | |
3117 | * pending shall cause the pending signal to be discarded, | |
3118 | * whether or not it is blocked." | |
3119 | * | |
3120 | * "Setting a signal action to SIG_DFL for a signal that is | |
3121 | * pending and whose default action is to ignore the signal | |
3122 | * (for example, SIGCHLD), shall cause the pending signal to | |
3123 | * be discarded, whether or not it is blocked" | |
3124 | */ | |
35de254d | 3125 | if (sig_handler_ignored(sig_handler(t, sig), sig)) { |
71fabd5e GA |
3126 | sigemptyset(&mask); |
3127 | sigaddset(&mask, sig); | |
3128 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 3129 | do { |
71fabd5e | 3130 | rm_from_queue_full(&mask, &t->pending); |
8d38f203 | 3131 | } while_each_thread(current, t); |
1da177e4 | 3132 | } |
1da177e4 LT |
3133 | } |
3134 | ||
3135 | spin_unlock_irq(¤t->sighand->siglock); | |
3136 | return 0; | |
3137 | } | |
3138 | ||
e9b04b5b | 3139 | static int |
1da177e4 LT |
3140 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) |
3141 | { | |
3142 | stack_t oss; | |
3143 | int error; | |
3144 | ||
0083fc2c LT |
3145 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
3146 | oss.ss_size = current->sas_ss_size; | |
3147 | oss.ss_flags = sas_ss_flags(sp); | |
1da177e4 LT |
3148 | |
3149 | if (uss) { | |
3150 | void __user *ss_sp; | |
3151 | size_t ss_size; | |
3152 | int ss_flags; | |
3153 | ||
3154 | error = -EFAULT; | |
0dd8486b LT |
3155 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
3156 | goto out; | |
3157 | error = __get_user(ss_sp, &uss->ss_sp) | | |
3158 | __get_user(ss_flags, &uss->ss_flags) | | |
3159 | __get_user(ss_size, &uss->ss_size); | |
3160 | if (error) | |
1da177e4 LT |
3161 | goto out; |
3162 | ||
3163 | error = -EPERM; | |
3164 | if (on_sig_stack(sp)) | |
3165 | goto out; | |
3166 | ||
3167 | error = -EINVAL; | |
3168 | /* | |
5aba085e | 3169 | * Note - this code used to test ss_flags incorrectly: |
1da177e4 LT |
3170 | * old code may have been written using ss_flags==0 |
3171 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
3172 | * way that worked) - this fix preserves that older | |
5aba085e | 3173 | * mechanism. |
1da177e4 LT |
3174 | */ |
3175 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
3176 | goto out; | |
3177 | ||
3178 | if (ss_flags == SS_DISABLE) { | |
3179 | ss_size = 0; | |
3180 | ss_sp = NULL; | |
3181 | } else { | |
3182 | error = -ENOMEM; | |
3183 | if (ss_size < MINSIGSTKSZ) | |
3184 | goto out; | |
3185 | } | |
3186 | ||
3187 | current->sas_ss_sp = (unsigned long) ss_sp; | |
3188 | current->sas_ss_size = ss_size; | |
3189 | } | |
3190 | ||
0083fc2c | 3191 | error = 0; |
1da177e4 LT |
3192 | if (uoss) { |
3193 | error = -EFAULT; | |
0083fc2c | 3194 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 3195 | goto out; |
0083fc2c LT |
3196 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
3197 | __put_user(oss.ss_size, &uoss->ss_size) | | |
3198 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
3199 | } |
3200 | ||
1da177e4 LT |
3201 | out: |
3202 | return error; | |
3203 | } | |
6bf9adfc AV |
3204 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3205 | { | |
3206 | return do_sigaltstack(uss, uoss, current_user_stack_pointer()); | |
3207 | } | |
1da177e4 | 3208 | |
5c49574f AV |
3209 | int restore_altstack(const stack_t __user *uss) |
3210 | { | |
3211 | int err = do_sigaltstack(uss, NULL, current_user_stack_pointer()); | |
3212 | /* squash all but EFAULT for now */ | |
3213 | return err == -EFAULT ? err : 0; | |
3214 | } | |
3215 | ||
c40702c4 AV |
3216 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3217 | { | |
3218 | struct task_struct *t = current; | |
3219 | return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | | |
3220 | __put_user(sas_ss_flags(sp), &uss->ss_flags) | | |
3221 | __put_user(t->sas_ss_size, &uss->ss_size); | |
3222 | } | |
3223 | ||
90268439 | 3224 | #ifdef CONFIG_COMPAT |
90228fc1 AV |
3225 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
3226 | const compat_stack_t __user *, uss_ptr, | |
3227 | compat_stack_t __user *, uoss_ptr) | |
90268439 AV |
3228 | { |
3229 | stack_t uss, uoss; | |
3230 | int ret; | |
3231 | mm_segment_t seg; | |
3232 | ||
3233 | if (uss_ptr) { | |
3234 | compat_stack_t uss32; | |
3235 | ||
3236 | memset(&uss, 0, sizeof(stack_t)); | |
3237 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) | |
3238 | return -EFAULT; | |
3239 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
3240 | uss.ss_flags = uss32.ss_flags; | |
3241 | uss.ss_size = uss32.ss_size; | |
3242 | } | |
3243 | seg = get_fs(); | |
3244 | set_fs(KERNEL_DS); | |
3245 | ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), | |
3246 | (stack_t __force __user *) &uoss, | |
3247 | compat_user_stack_pointer()); | |
3248 | set_fs(seg); | |
3249 | if (ret >= 0 && uoss_ptr) { | |
3250 | if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) || | |
3251 | __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) || | |
3252 | __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) || | |
3253 | __put_user(uoss.ss_size, &uoss_ptr->ss_size)) | |
3254 | ret = -EFAULT; | |
3255 | } | |
3256 | return ret; | |
3257 | } | |
3258 | ||
3259 | int compat_restore_altstack(const compat_stack_t __user *uss) | |
3260 | { | |
3261 | int err = compat_sys_sigaltstack(uss, NULL); | |
3262 | /* squash all but -EFAULT for now */ | |
3263 | return err == -EFAULT ? err : 0; | |
3264 | } | |
c40702c4 AV |
3265 | |
3266 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
3267 | { | |
3268 | struct task_struct *t = current; | |
3269 | return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) | | |
3270 | __put_user(sas_ss_flags(sp), &uss->ss_flags) | | |
3271 | __put_user(t->sas_ss_size, &uss->ss_size); | |
3272 | } | |
90268439 | 3273 | #endif |
1da177e4 LT |
3274 | |
3275 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3276 | ||
41c57892 RD |
3277 | /** |
3278 | * sys_sigpending - examine pending signals | |
3279 | * @set: where mask of pending signal is returned | |
3280 | */ | |
b290ebe2 | 3281 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 | 3282 | { |
fe9c1db2 | 3283 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); |
1da177e4 LT |
3284 | } |
3285 | ||
3286 | #endif | |
3287 | ||
3288 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3289 | /** |
3290 | * sys_sigprocmask - examine and change blocked signals | |
3291 | * @how: whether to add, remove, or set signals | |
b013c399 | 3292 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3293 | * @oset: previous value of signal mask if non-null |
3294 | * | |
5aba085e RD |
3295 | * Some platforms have their own version with special arguments; |
3296 | * others support only sys_rt_sigprocmask. | |
3297 | */ | |
1da177e4 | 3298 | |
b013c399 | 3299 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3300 | old_sigset_t __user *, oset) |
1da177e4 | 3301 | { |
1da177e4 | 3302 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3303 | sigset_t new_blocked; |
1da177e4 | 3304 | |
b013c399 | 3305 | old_set = current->blocked.sig[0]; |
1da177e4 | 3306 | |
b013c399 ON |
3307 | if (nset) { |
3308 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3309 | return -EFAULT; | |
1da177e4 | 3310 | |
2e4f7c77 | 3311 | new_blocked = current->blocked; |
1da177e4 | 3312 | |
1da177e4 | 3313 | switch (how) { |
1da177e4 | 3314 | case SIG_BLOCK: |
2e4f7c77 | 3315 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3316 | break; |
3317 | case SIG_UNBLOCK: | |
2e4f7c77 | 3318 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3319 | break; |
3320 | case SIG_SETMASK: | |
2e4f7c77 | 3321 | new_blocked.sig[0] = new_set; |
1da177e4 | 3322 | break; |
2e4f7c77 ON |
3323 | default: |
3324 | return -EINVAL; | |
1da177e4 LT |
3325 | } |
3326 | ||
0c4a8423 | 3327 | set_current_blocked(&new_blocked); |
b013c399 ON |
3328 | } |
3329 | ||
3330 | if (oset) { | |
1da177e4 | 3331 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3332 | return -EFAULT; |
1da177e4 | 3333 | } |
b013c399 ON |
3334 | |
3335 | return 0; | |
1da177e4 LT |
3336 | } |
3337 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3338 | ||
eaca6eae | 3339 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
3340 | /** |
3341 | * sys_rt_sigaction - alter an action taken by a process | |
3342 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3343 | * @act: new sigaction |
3344 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3345 | * @sigsetsize: size of sigset_t type |
3346 | */ | |
d4e82042 HC |
3347 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3348 | const struct sigaction __user *, act, | |
3349 | struct sigaction __user *, oact, | |
3350 | size_t, sigsetsize) | |
1da177e4 LT |
3351 | { |
3352 | struct k_sigaction new_sa, old_sa; | |
3353 | int ret = -EINVAL; | |
3354 | ||
3355 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3356 | if (sigsetsize != sizeof(sigset_t)) | |
3357 | goto out; | |
3358 | ||
3359 | if (act) { | |
3360 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3361 | return -EFAULT; | |
3362 | } | |
3363 | ||
3364 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3365 | ||
3366 | if (!ret && oact) { | |
3367 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3368 | return -EFAULT; | |
3369 | } | |
3370 | out: | |
3371 | return ret; | |
3372 | } | |
08d32fe5 | 3373 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
3374 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3375 | const struct compat_sigaction __user *, act, | |
3376 | struct compat_sigaction __user *, oact, | |
3377 | compat_size_t, sigsetsize) | |
3378 | { | |
3379 | struct k_sigaction new_ka, old_ka; | |
3380 | compat_sigset_t mask; | |
3381 | #ifdef __ARCH_HAS_SA_RESTORER | |
3382 | compat_uptr_t restorer; | |
3383 | #endif | |
3384 | int ret; | |
3385 | ||
3386 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3387 | if (sigsetsize != sizeof(compat_sigset_t)) | |
3388 | return -EINVAL; | |
3389 | ||
3390 | if (act) { | |
3391 | compat_uptr_t handler; | |
3392 | ret = get_user(handler, &act->sa_handler); | |
3393 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3394 | #ifdef __ARCH_HAS_SA_RESTORER | |
3395 | ret |= get_user(restorer, &act->sa_restorer); | |
3396 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3397 | #endif | |
3398 | ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask)); | |
3ddc5b46 | 3399 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
3400 | if (ret) |
3401 | return -EFAULT; | |
3402 | sigset_from_compat(&new_ka.sa.sa_mask, &mask); | |
3403 | } | |
3404 | ||
3405 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3406 | if (!ret && oact) { | |
3407 | sigset_to_compat(&mask, &old_ka.sa.sa_mask); | |
3408 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3409 | &oact->sa_handler); | |
3410 | ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask)); | |
3ddc5b46 | 3411 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
3412 | #ifdef __ARCH_HAS_SA_RESTORER |
3413 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3414 | &oact->sa_restorer); | |
3415 | #endif | |
3416 | } | |
3417 | return ret; | |
3418 | } | |
3419 | #endif | |
eaca6eae | 3420 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 3421 | |
495dfbf7 AV |
3422 | #ifdef CONFIG_OLD_SIGACTION |
3423 | SYSCALL_DEFINE3(sigaction, int, sig, | |
3424 | const struct old_sigaction __user *, act, | |
3425 | struct old_sigaction __user *, oact) | |
3426 | { | |
3427 | struct k_sigaction new_ka, old_ka; | |
3428 | int ret; | |
3429 | ||
3430 | if (act) { | |
3431 | old_sigset_t mask; | |
3432 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3433 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
3434 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
3435 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3436 | __get_user(mask, &act->sa_mask)) | |
3437 | return -EFAULT; | |
3438 | #ifdef __ARCH_HAS_KA_RESTORER | |
3439 | new_ka.ka_restorer = NULL; | |
3440 | #endif | |
3441 | siginitset(&new_ka.sa.sa_mask, mask); | |
3442 | } | |
3443 | ||
3444 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3445 | ||
3446 | if (!ret && oact) { | |
3447 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3448 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
3449 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
3450 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3451 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3452 | return -EFAULT; | |
3453 | } | |
3454 | ||
3455 | return ret; | |
3456 | } | |
3457 | #endif | |
3458 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
3459 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
3460 | const struct compat_old_sigaction __user *, act, | |
3461 | struct compat_old_sigaction __user *, oact) | |
3462 | { | |
3463 | struct k_sigaction new_ka, old_ka; | |
3464 | int ret; | |
3465 | compat_old_sigset_t mask; | |
3466 | compat_uptr_t handler, restorer; | |
3467 | ||
3468 | if (act) { | |
3469 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3470 | __get_user(handler, &act->sa_handler) || | |
3471 | __get_user(restorer, &act->sa_restorer) || | |
3472 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3473 | __get_user(mask, &act->sa_mask)) | |
3474 | return -EFAULT; | |
3475 | ||
3476 | #ifdef __ARCH_HAS_KA_RESTORER | |
3477 | new_ka.ka_restorer = NULL; | |
3478 | #endif | |
3479 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3480 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3481 | siginitset(&new_ka.sa.sa_mask, mask); | |
3482 | } | |
3483 | ||
3484 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3485 | ||
3486 | if (!ret && oact) { | |
3487 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3488 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3489 | &oact->sa_handler) || | |
3490 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3491 | &oact->sa_restorer) || | |
3492 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3493 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3494 | return -EFAULT; | |
3495 | } | |
3496 | return ret; | |
3497 | } | |
3498 | #endif | |
1da177e4 | 3499 | |
f6187769 | 3500 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
3501 | |
3502 | /* | |
3503 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3504 | */ | |
a5f8fa9e | 3505 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3506 | { |
3507 | /* SMP safe */ | |
3508 | return current->blocked.sig[0]; | |
3509 | } | |
3510 | ||
a5f8fa9e | 3511 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3512 | { |
c1095c6d ON |
3513 | int old = current->blocked.sig[0]; |
3514 | sigset_t newset; | |
1da177e4 | 3515 | |
5ba53ff6 | 3516 | siginitset(&newset, newmask); |
c1095c6d | 3517 | set_current_blocked(&newset); |
1da177e4 LT |
3518 | |
3519 | return old; | |
3520 | } | |
f6187769 | 3521 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
3522 | |
3523 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3524 | /* | |
3525 | * For backwards compatibility. Functionality superseded by sigaction. | |
3526 | */ | |
a5f8fa9e | 3527 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3528 | { |
3529 | struct k_sigaction new_sa, old_sa; | |
3530 | int ret; | |
3531 | ||
3532 | new_sa.sa.sa_handler = handler; | |
3533 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3534 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3535 | |
3536 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3537 | ||
3538 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3539 | } | |
3540 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3541 | ||
3542 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3543 | ||
a5f8fa9e | 3544 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3545 | { |
d92fcf05 ON |
3546 | while (!signal_pending(current)) { |
3547 | current->state = TASK_INTERRUPTIBLE; | |
3548 | schedule(); | |
3549 | } | |
1da177e4 LT |
3550 | return -ERESTARTNOHAND; |
3551 | } | |
3552 | ||
3553 | #endif | |
3554 | ||
68f3f16d AV |
3555 | int sigsuspend(sigset_t *set) |
3556 | { | |
68f3f16d AV |
3557 | current->saved_sigmask = current->blocked; |
3558 | set_current_blocked(set); | |
3559 | ||
3560 | current->state = TASK_INTERRUPTIBLE; | |
3561 | schedule(); | |
3562 | set_restore_sigmask(); | |
3563 | return -ERESTARTNOHAND; | |
3564 | } | |
68f3f16d | 3565 | |
41c57892 RD |
3566 | /** |
3567 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3568 | * @unewset value until a signal is received | |
3569 | * @unewset: new signal mask value | |
3570 | * @sigsetsize: size of sigset_t type | |
3571 | */ | |
d4e82042 | 3572 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3573 | { |
3574 | sigset_t newset; | |
3575 | ||
3576 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3577 | if (sigsetsize != sizeof(sigset_t)) | |
3578 | return -EINVAL; | |
3579 | ||
3580 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3581 | return -EFAULT; | |
68f3f16d | 3582 | return sigsuspend(&newset); |
150256d8 | 3583 | } |
ad4b65a4 AV |
3584 | |
3585 | #ifdef CONFIG_COMPAT | |
3586 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
3587 | { | |
3588 | #ifdef __BIG_ENDIAN | |
3589 | sigset_t newset; | |
3590 | compat_sigset_t newset32; | |
3591 | ||
3592 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3593 | if (sigsetsize != sizeof(sigset_t)) | |
3594 | return -EINVAL; | |
3595 | ||
3596 | if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t))) | |
3597 | return -EFAULT; | |
3598 | sigset_from_compat(&newset, &newset32); | |
3599 | return sigsuspend(&newset); | |
3600 | #else | |
3601 | /* on little-endian bitmaps don't care about granularity */ | |
3602 | return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize); | |
3603 | #endif | |
3604 | } | |
3605 | #endif | |
150256d8 | 3606 | |
0a0e8cdf AV |
3607 | #ifdef CONFIG_OLD_SIGSUSPEND |
3608 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
3609 | { | |
3610 | sigset_t blocked; | |
3611 | siginitset(&blocked, mask); | |
3612 | return sigsuspend(&blocked); | |
3613 | } | |
3614 | #endif | |
3615 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
3616 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
3617 | { | |
3618 | sigset_t blocked; | |
3619 | siginitset(&blocked, mask); | |
3620 | return sigsuspend(&blocked); | |
3621 | } | |
3622 | #endif | |
150256d8 | 3623 | |
52f5684c | 3624 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
3625 | { |
3626 | return NULL; | |
3627 | } | |
3628 | ||
1da177e4 LT |
3629 | void __init signals_init(void) |
3630 | { | |
0a31bd5f | 3631 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3632 | } |
67fc4e0c JW |
3633 | |
3634 | #ifdef CONFIG_KGDB_KDB | |
3635 | #include <linux/kdb.h> | |
3636 | /* | |
3637 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3638 | * signal internals. This function checks if the required locks are | |
3639 | * available before calling the main signal code, to avoid kdb | |
3640 | * deadlocks. | |
3641 | */ | |
3642 | void | |
3643 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3644 | { | |
3645 | static struct task_struct *kdb_prev_t; | |
3646 | int sig, new_t; | |
3647 | if (!spin_trylock(&t->sighand->siglock)) { | |
3648 | kdb_printf("Can't do kill command now.\n" | |
3649 | "The sigmask lock is held somewhere else in " | |
3650 | "kernel, try again later\n"); | |
3651 | return; | |
3652 | } | |
3653 | spin_unlock(&t->sighand->siglock); | |
3654 | new_t = kdb_prev_t != t; | |
3655 | kdb_prev_t = t; | |
3656 | if (t->state != TASK_RUNNING && new_t) { | |
3657 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3658 | "kdb risks deadlock\n" | |
3659 | "on the run queue locks. " | |
3660 | "The signal has _not_ been sent.\n" | |
3661 | "Reissue the kill command if you want to risk " | |
3662 | "the deadlock.\n"); | |
3663 | return; | |
3664 | } | |
3665 | sig = info->si_signo; | |
3666 | if (send_sig_info(sig, info, t)) | |
3667 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3668 | sig, t->pid); | |
3669 | else | |
3670 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3671 | } | |
3672 | #endif /* CONFIG_KGDB_KDB */ |