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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 | 41 | #include <asm/param.h> |
7c0f6ba6 | 42 | #include <linux/uaccess.h> |
1da177e4 LT |
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 | ||
747800ef | 227 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
f84d49b2 NO |
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 | */ | |
b76808e6 | 248 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
7dd3db54 TH |
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 | */ | |
b76808e6 | 300 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long 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 | /* | |
9e7c8f8c | 417 | * Flush all pending signals for this kthread. |
1da177e4 | 418 | */ |
c81addc9 | 419 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
420 | { |
421 | unsigned long flags; | |
422 | ||
423 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
9e7c8f8c ON |
424 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
425 | flush_sigqueue(&t->pending); | |
426 | flush_sigqueue(&t->signal->shared_pending); | |
1da177e4 LT |
427 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
428 | } | |
429 | ||
baa73d9e | 430 | #ifdef CONFIG_POSIX_TIMERS |
cbaffba1 ON |
431 | static void __flush_itimer_signals(struct sigpending *pending) |
432 | { | |
433 | sigset_t signal, retain; | |
434 | struct sigqueue *q, *n; | |
435 | ||
436 | signal = pending->signal; | |
437 | sigemptyset(&retain); | |
438 | ||
439 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
440 | int sig = q->info.si_signo; | |
441 | ||
442 | if (likely(q->info.si_code != SI_TIMER)) { | |
443 | sigaddset(&retain, sig); | |
444 | } else { | |
445 | sigdelset(&signal, sig); | |
446 | list_del_init(&q->list); | |
447 | __sigqueue_free(q); | |
448 | } | |
449 | } | |
450 | ||
451 | sigorsets(&pending->signal, &signal, &retain); | |
452 | } | |
453 | ||
454 | void flush_itimer_signals(void) | |
455 | { | |
456 | struct task_struct *tsk = current; | |
457 | unsigned long flags; | |
458 | ||
459 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
460 | __flush_itimer_signals(&tsk->pending); | |
461 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
462 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
463 | } | |
baa73d9e | 464 | #endif |
cbaffba1 | 465 | |
10ab825b ON |
466 | void ignore_signals(struct task_struct *t) |
467 | { | |
468 | int i; | |
469 | ||
470 | for (i = 0; i < _NSIG; ++i) | |
471 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
472 | ||
473 | flush_signals(t); | |
474 | } | |
475 | ||
1da177e4 LT |
476 | /* |
477 | * Flush all handlers for a task. | |
478 | */ | |
479 | ||
480 | void | |
481 | flush_signal_handlers(struct task_struct *t, int force_default) | |
482 | { | |
483 | int i; | |
484 | struct k_sigaction *ka = &t->sighand->action[0]; | |
485 | for (i = _NSIG ; i != 0 ; i--) { | |
486 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
487 | ka->sa.sa_handler = SIG_DFL; | |
488 | ka->sa.sa_flags = 0; | |
522cff14 | 489 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
490 | ka->sa.sa_restorer = NULL; |
491 | #endif | |
1da177e4 LT |
492 | sigemptyset(&ka->sa.sa_mask); |
493 | ka++; | |
494 | } | |
495 | } | |
496 | ||
abd4f750 MAS |
497 | int unhandled_signal(struct task_struct *tsk, int sig) |
498 | { | |
445a91d2 | 499 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 500 | if (is_global_init(tsk)) |
abd4f750 | 501 | return 1; |
445a91d2 | 502 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 503 | return 0; |
a288eecc TH |
504 | /* if ptraced, let the tracer determine */ |
505 | return !tsk->ptrace; | |
abd4f750 MAS |
506 | } |
507 | ||
100360f0 | 508 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
509 | { |
510 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 511 | |
1da177e4 LT |
512 | /* |
513 | * Collect the siginfo appropriate to this signal. Check if | |
514 | * there is another siginfo for the same signal. | |
515 | */ | |
516 | list_for_each_entry(q, &list->list, list) { | |
517 | if (q->info.si_signo == sig) { | |
d4434207 ON |
518 | if (first) |
519 | goto still_pending; | |
1da177e4 LT |
520 | first = q; |
521 | } | |
522 | } | |
d4434207 ON |
523 | |
524 | sigdelset(&list->signal, sig); | |
525 | ||
1da177e4 | 526 | if (first) { |
d4434207 | 527 | still_pending: |
1da177e4 LT |
528 | list_del_init(&first->list); |
529 | copy_siginfo(info, &first->info); | |
530 | __sigqueue_free(first); | |
1da177e4 | 531 | } else { |
5aba085e RD |
532 | /* |
533 | * Ok, it wasn't in the queue. This must be | |
534 | * a fast-pathed signal or we must have been | |
535 | * out of queue space. So zero out the info. | |
1da177e4 | 536 | */ |
1da177e4 LT |
537 | info->si_signo = sig; |
538 | info->si_errno = 0; | |
7486e5d9 | 539 | info->si_code = SI_USER; |
1da177e4 LT |
540 | info->si_pid = 0; |
541 | info->si_uid = 0; | |
542 | } | |
1da177e4 LT |
543 | } |
544 | ||
545 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
546 | siginfo_t *info) | |
547 | { | |
27d91e07 | 548 | int sig = next_signal(pending, mask); |
1da177e4 | 549 | |
2e01fabe | 550 | if (sig) |
100360f0 | 551 | collect_signal(sig, pending, info); |
1da177e4 LT |
552 | return sig; |
553 | } | |
554 | ||
555 | /* | |
5aba085e | 556 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
557 | * expected to free it. |
558 | * | |
559 | * All callers have to hold the siglock. | |
560 | */ | |
561 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
562 | { | |
c5363d03 | 563 | int signr; |
caec4e8d BH |
564 | |
565 | /* We only dequeue private signals from ourselves, we don't let | |
566 | * signalfd steal them | |
567 | */ | |
b8fceee1 | 568 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 569 | if (!signr) { |
1da177e4 LT |
570 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
571 | mask, info); | |
baa73d9e | 572 | #ifdef CONFIG_POSIX_TIMERS |
8bfd9a7a TG |
573 | /* |
574 | * itimer signal ? | |
575 | * | |
576 | * itimers are process shared and we restart periodic | |
577 | * itimers in the signal delivery path to prevent DoS | |
578 | * attacks in the high resolution timer case. This is | |
5aba085e | 579 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
580 | * itimers, as the SIGALRM is a legacy signal and only |
581 | * queued once. Changing the restart behaviour to | |
582 | * restart the timer in the signal dequeue path is | |
583 | * reducing the timer noise on heavy loaded !highres | |
584 | * systems too. | |
585 | */ | |
586 | if (unlikely(signr == SIGALRM)) { | |
587 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
588 | ||
589 | if (!hrtimer_is_queued(tmr) && | |
2456e855 | 590 | tsk->signal->it_real_incr != 0) { |
8bfd9a7a TG |
591 | hrtimer_forward(tmr, tmr->base->get_time(), |
592 | tsk->signal->it_real_incr); | |
593 | hrtimer_restart(tmr); | |
594 | } | |
595 | } | |
baa73d9e | 596 | #endif |
8bfd9a7a | 597 | } |
c5363d03 | 598 | |
b8fceee1 | 599 | recalc_sigpending(); |
c5363d03 PE |
600 | if (!signr) |
601 | return 0; | |
602 | ||
603 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
604 | /* |
605 | * Set a marker that we have dequeued a stop signal. Our | |
606 | * caller might release the siglock and then the pending | |
607 | * stop signal it is about to process is no longer in the | |
608 | * pending bitmasks, but must still be cleared by a SIGCONT | |
609 | * (and overruled by a SIGKILL). So those cases clear this | |
610 | * shared flag after we've set it. Note that this flag may | |
611 | * remain set after the signal we return is ignored or | |
612 | * handled. That doesn't matter because its only purpose | |
613 | * is to alert stop-signal processing code when another | |
614 | * processor has come along and cleared the flag. | |
615 | */ | |
a8f072c1 | 616 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 617 | } |
baa73d9e | 618 | #ifdef CONFIG_POSIX_TIMERS |
c5363d03 | 619 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
620 | /* |
621 | * Release the siglock to ensure proper locking order | |
622 | * of timer locks outside of siglocks. Note, we leave | |
623 | * irqs disabled here, since the posix-timers code is | |
624 | * about to disable them again anyway. | |
625 | */ | |
626 | spin_unlock(&tsk->sighand->siglock); | |
627 | do_schedule_next_timer(info); | |
628 | spin_lock(&tsk->sighand->siglock); | |
629 | } | |
baa73d9e | 630 | #endif |
1da177e4 LT |
631 | return signr; |
632 | } | |
633 | ||
634 | /* | |
635 | * Tell a process that it has a new active signal.. | |
636 | * | |
637 | * NOTE! we rely on the previous spin_lock to | |
638 | * lock interrupts for us! We can only be called with | |
639 | * "siglock" held, and the local interrupt must | |
640 | * have been disabled when that got acquired! | |
641 | * | |
642 | * No need to set need_resched since signal event passing | |
643 | * goes through ->blocked | |
644 | */ | |
910ffdb1 | 645 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 646 | { |
1da177e4 | 647 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 648 | /* |
910ffdb1 | 649 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 650 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
651 | * executing another processor and just now entering stopped state. |
652 | * By using wake_up_state, we ensure the process will wake up and | |
653 | * handle its death signal. | |
654 | */ | |
910ffdb1 | 655 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
656 | kick_process(t); |
657 | } | |
658 | ||
71fabd5e GA |
659 | /* |
660 | * Remove signals in mask from the pending set and queue. | |
661 | * Returns 1 if any signals were found. | |
662 | * | |
663 | * All callers must be holding the siglock. | |
71fabd5e | 664 | */ |
c09c1441 | 665 | static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
71fabd5e GA |
666 | { |
667 | struct sigqueue *q, *n; | |
668 | sigset_t m; | |
669 | ||
670 | sigandsets(&m, mask, &s->signal); | |
671 | if (sigisemptyset(&m)) | |
672 | return 0; | |
673 | ||
702a5073 | 674 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
675 | list_for_each_entry_safe(q, n, &s->list, list) { |
676 | if (sigismember(mask, q->info.si_signo)) { | |
677 | list_del_init(&q->list); | |
678 | __sigqueue_free(q); | |
679 | } | |
680 | } | |
681 | return 1; | |
682 | } | |
1da177e4 | 683 | |
614c517d ON |
684 | static inline int is_si_special(const struct siginfo *info) |
685 | { | |
686 | return info <= SEND_SIG_FORCED; | |
687 | } | |
688 | ||
689 | static inline bool si_fromuser(const struct siginfo *info) | |
690 | { | |
691 | return info == SEND_SIG_NOINFO || | |
692 | (!is_si_special(info) && SI_FROMUSER(info)); | |
693 | } | |
694 | ||
39fd3393 SH |
695 | /* |
696 | * called with RCU read lock from check_kill_permission() | |
697 | */ | |
698 | static int kill_ok_by_cred(struct task_struct *t) | |
699 | { | |
700 | const struct cred *cred = current_cred(); | |
701 | const struct cred *tcred = __task_cred(t); | |
702 | ||
5af66203 EB |
703 | if (uid_eq(cred->euid, tcred->suid) || |
704 | uid_eq(cred->euid, tcred->uid) || | |
705 | uid_eq(cred->uid, tcred->suid) || | |
706 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
707 | return 1; |
708 | ||
c4a4d603 | 709 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
710 | return 1; |
711 | ||
712 | return 0; | |
713 | } | |
714 | ||
1da177e4 LT |
715 | /* |
716 | * Bad permissions for sending the signal | |
694f690d | 717 | * - the caller must hold the RCU read lock |
1da177e4 LT |
718 | */ |
719 | static int check_kill_permission(int sig, struct siginfo *info, | |
720 | struct task_struct *t) | |
721 | { | |
2e2ba22e | 722 | struct pid *sid; |
3b5e9e53 ON |
723 | int error; |
724 | ||
7ed20e1a | 725 | if (!valid_signal(sig)) |
3b5e9e53 ON |
726 | return -EINVAL; |
727 | ||
614c517d | 728 | if (!si_fromuser(info)) |
3b5e9e53 | 729 | return 0; |
e54dc243 | 730 | |
3b5e9e53 ON |
731 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
732 | if (error) | |
1da177e4 | 733 | return error; |
3b5e9e53 | 734 | |
065add39 | 735 | if (!same_thread_group(current, t) && |
39fd3393 | 736 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
737 | switch (sig) { |
738 | case SIGCONT: | |
2e2ba22e | 739 | sid = task_session(t); |
2e2ba22e ON |
740 | /* |
741 | * We don't return the error if sid == NULL. The | |
742 | * task was unhashed, the caller must notice this. | |
743 | */ | |
744 | if (!sid || sid == task_session(current)) | |
745 | break; | |
746 | default: | |
747 | return -EPERM; | |
748 | } | |
749 | } | |
c2f0c7c3 | 750 | |
e54dc243 | 751 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
752 | } |
753 | ||
fb1d910c TH |
754 | /** |
755 | * ptrace_trap_notify - schedule trap to notify ptracer | |
756 | * @t: tracee wanting to notify tracer | |
757 | * | |
758 | * This function schedules sticky ptrace trap which is cleared on the next | |
759 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
760 | * ptracer. | |
761 | * | |
544b2c91 TH |
762 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
763 | * ptracer is listening for events, tracee is woken up so that it can | |
764 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
765 | * eventually taken without returning to userland after the existing traps | |
766 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
767 | * |
768 | * CONTEXT: | |
769 | * Must be called with @task->sighand->siglock held. | |
770 | */ | |
771 | static void ptrace_trap_notify(struct task_struct *t) | |
772 | { | |
773 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
774 | assert_spin_locked(&t->sighand->siglock); | |
775 | ||
776 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 777 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
778 | } |
779 | ||
1da177e4 | 780 | /* |
7e695a5e ON |
781 | * Handle magic process-wide effects of stop/continue signals. Unlike |
782 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
783 | * time regardless of blocking, ignoring, or handling. This does the |
784 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
785 | * signals. The process stop is done as a signal action for SIG_DFL. |
786 | * | |
787 | * Returns true if the signal should be actually delivered, otherwise | |
788 | * it should be dropped. | |
1da177e4 | 789 | */ |
403bad72 | 790 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 791 | { |
ad16a460 | 792 | struct signal_struct *signal = p->signal; |
1da177e4 | 793 | struct task_struct *t; |
9490592f | 794 | sigset_t flush; |
1da177e4 | 795 | |
403bad72 | 796 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { |
5fa534c9 | 797 | if (!(signal->flags & SIGNAL_GROUP_EXIT)) |
403bad72 | 798 | return sig == SIGKILL; |
1da177e4 | 799 | /* |
7e695a5e | 800 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 801 | */ |
7e695a5e | 802 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
803 | /* |
804 | * This is a stop signal. Remove SIGCONT from all queues. | |
805 | */ | |
9490592f | 806 | siginitset(&flush, sigmask(SIGCONT)); |
c09c1441 | 807 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 808 | for_each_thread(p, t) |
c09c1441 | 809 | flush_sigqueue_mask(&flush, &t->pending); |
1da177e4 | 810 | } else if (sig == SIGCONT) { |
fc321d2e | 811 | unsigned int why; |
1da177e4 | 812 | /* |
1deac632 | 813 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 814 | */ |
9490592f | 815 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
c09c1441 | 816 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 817 | for_each_thread(p, t) { |
c09c1441 | 818 | flush_sigqueue_mask(&flush, &t->pending); |
3759a0d9 | 819 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
fb1d910c TH |
820 | if (likely(!(t->ptrace & PT_SEIZED))) |
821 | wake_up_state(t, __TASK_STOPPED); | |
822 | else | |
823 | ptrace_trap_notify(t); | |
9490592f | 824 | } |
1da177e4 | 825 | |
fc321d2e ON |
826 | /* |
827 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
828 | * | |
829 | * If we were in the middle of a group stop, we pretend it | |
830 | * was already finished, and then continued. Since SIGCHLD | |
831 | * doesn't queue we report only CLD_STOPPED, as if the next | |
832 | * CLD_CONTINUED was dropped. | |
833 | */ | |
834 | why = 0; | |
ad16a460 | 835 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 836 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 837 | else if (signal->group_stop_count) |
fc321d2e ON |
838 | why |= SIGNAL_CLD_STOPPED; |
839 | ||
840 | if (why) { | |
021e1ae3 | 841 | /* |
ae6d2ed7 | 842 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
843 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
844 | * notify its parent. See get_signal_to_deliver(). | |
845 | */ | |
ad16a460 ON |
846 | signal->flags = why | SIGNAL_STOP_CONTINUED; |
847 | signal->group_stop_count = 0; | |
848 | signal->group_exit_code = 0; | |
1da177e4 | 849 | } |
1da177e4 | 850 | } |
7e695a5e | 851 | |
def8cf72 | 852 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
853 | } |
854 | ||
71f11dc0 ON |
855 | /* |
856 | * Test if P wants to take SIG. After we've checked all threads with this, | |
857 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
858 | * blocking SIG were ruled out because they are not running and already | |
859 | * have pending signals. Such threads will dequeue from the shared queue | |
860 | * as soon as they're available, so putting the signal on the shared queue | |
861 | * will be equivalent to sending it to one such thread. | |
862 | */ | |
863 | static inline int wants_signal(int sig, struct task_struct *p) | |
864 | { | |
865 | if (sigismember(&p->blocked, sig)) | |
866 | return 0; | |
867 | if (p->flags & PF_EXITING) | |
868 | return 0; | |
869 | if (sig == SIGKILL) | |
870 | return 1; | |
871 | if (task_is_stopped_or_traced(p)) | |
872 | return 0; | |
873 | return task_curr(p) || !signal_pending(p); | |
874 | } | |
875 | ||
5fcd835b | 876 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
877 | { |
878 | struct signal_struct *signal = p->signal; | |
879 | struct task_struct *t; | |
880 | ||
881 | /* | |
882 | * Now find a thread we can wake up to take the signal off the queue. | |
883 | * | |
884 | * If the main thread wants the signal, it gets first crack. | |
885 | * Probably the least surprising to the average bear. | |
886 | */ | |
887 | if (wants_signal(sig, p)) | |
888 | t = p; | |
5fcd835b | 889 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
890 | /* |
891 | * There is just one thread and it does not need to be woken. | |
892 | * It will dequeue unblocked signals before it runs again. | |
893 | */ | |
894 | return; | |
895 | else { | |
896 | /* | |
897 | * Otherwise try to find a suitable thread. | |
898 | */ | |
899 | t = signal->curr_target; | |
900 | while (!wants_signal(sig, t)) { | |
901 | t = next_thread(t); | |
902 | if (t == signal->curr_target) | |
903 | /* | |
904 | * No thread needs to be woken. | |
905 | * Any eligible threads will see | |
906 | * the signal in the queue soon. | |
907 | */ | |
908 | return; | |
909 | } | |
910 | signal->curr_target = t; | |
911 | } | |
912 | ||
913 | /* | |
914 | * Found a killable thread. If the signal will be fatal, | |
915 | * then start taking the whole group down immediately. | |
916 | */ | |
fae5fa44 ON |
917 | if (sig_fatal(p, sig) && |
918 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 919 | !sigismember(&t->real_blocked, sig) && |
a288eecc | 920 | (sig == SIGKILL || !t->ptrace)) { |
71f11dc0 ON |
921 | /* |
922 | * This signal will be fatal to the whole group. | |
923 | */ | |
924 | if (!sig_kernel_coredump(sig)) { | |
925 | /* | |
926 | * Start a group exit and wake everybody up. | |
927 | * This way we don't have other threads | |
928 | * running and doing things after a slower | |
929 | * thread has the fatal signal pending. | |
930 | */ | |
931 | signal->flags = SIGNAL_GROUP_EXIT; | |
932 | signal->group_exit_code = sig; | |
933 | signal->group_stop_count = 0; | |
934 | t = p; | |
935 | do { | |
6dfca329 | 936 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
937 | sigaddset(&t->pending.signal, SIGKILL); |
938 | signal_wake_up(t, 1); | |
939 | } while_each_thread(p, t); | |
940 | return; | |
941 | } | |
942 | } | |
943 | ||
944 | /* | |
945 | * The signal is already in the shared-pending queue. | |
946 | * Tell the chosen thread to wake up and dequeue it. | |
947 | */ | |
948 | signal_wake_up(t, sig == SIGKILL); | |
949 | return; | |
950 | } | |
951 | ||
af7fff9c PE |
952 | static inline int legacy_queue(struct sigpending *signals, int sig) |
953 | { | |
954 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
955 | } | |
956 | ||
6b550f94 SH |
957 | #ifdef CONFIG_USER_NS |
958 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
959 | { | |
960 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
961 | return; | |
962 | ||
963 | if (SI_FROMKERNEL(info)) | |
964 | return; | |
965 | ||
078de5f7 EB |
966 | rcu_read_lock(); |
967 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
968 | make_kuid(current_user_ns(), info->si_uid)); | |
969 | rcu_read_unlock(); | |
6b550f94 SH |
970 | } |
971 | #else | |
972 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
973 | { | |
974 | return; | |
975 | } | |
976 | #endif | |
977 | ||
7978b567 SB |
978 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
979 | int group, int from_ancestor_ns) | |
1da177e4 | 980 | { |
2ca3515a | 981 | struct sigpending *pending; |
6e65acba | 982 | struct sigqueue *q; |
7a0aeb14 | 983 | int override_rlimit; |
6c303d3a | 984 | int ret = 0, result; |
0a16b607 | 985 | |
6e65acba | 986 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 987 | |
6c303d3a | 988 | result = TRACE_SIGNAL_IGNORED; |
629d362b ON |
989 | if (!prepare_signal(sig, t, |
990 | from_ancestor_ns || (info == SEND_SIG_FORCED))) | |
6c303d3a | 991 | goto ret; |
2ca3515a ON |
992 | |
993 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
994 | /* |
995 | * Short-circuit ignored signals and support queuing | |
996 | * exactly one non-rt signal, so that we can get more | |
997 | * detailed information about the cause of the signal. | |
998 | */ | |
6c303d3a | 999 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1000 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1001 | goto ret; |
1002 | ||
1003 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1004 | /* |
1005 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1006 | * or SIGKILL. | |
1007 | */ | |
b67a1b9e | 1008 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1009 | goto out_set; |
1010 | ||
5aba085e RD |
1011 | /* |
1012 | * Real-time signals must be queued if sent by sigqueue, or | |
1013 | * some other real-time mechanism. It is implementation | |
1014 | * defined whether kill() does so. We attempt to do so, on | |
1015 | * the principle of least surprise, but since kill is not | |
1016 | * allowed to fail with EAGAIN when low on memory we just | |
1017 | * make sure at least one signal gets delivered and don't | |
1018 | * pass on the info struct. | |
1019 | */ | |
7a0aeb14 VN |
1020 | if (sig < SIGRTMIN) |
1021 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1022 | else | |
1023 | override_rlimit = 0; | |
1024 | ||
f84d49b2 | 1025 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1026 | override_rlimit); |
1da177e4 | 1027 | if (q) { |
2ca3515a | 1028 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1029 | switch ((unsigned long) info) { |
b67a1b9e | 1030 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1031 | q->info.si_signo = sig; |
1032 | q->info.si_errno = 0; | |
1033 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1034 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1035 | task_active_pid_ns(t)); |
078de5f7 | 1036 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1037 | break; |
b67a1b9e | 1038 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1039 | q->info.si_signo = sig; |
1040 | q->info.si_errno = 0; | |
1041 | q->info.si_code = SI_KERNEL; | |
1042 | q->info.si_pid = 0; | |
1043 | q->info.si_uid = 0; | |
1044 | break; | |
1045 | default: | |
1046 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1047 | if (from_ancestor_ns) |
1048 | q->info.si_pid = 0; | |
1da177e4 LT |
1049 | break; |
1050 | } | |
6b550f94 SH |
1051 | |
1052 | userns_fixup_signal_uid(&q->info, t); | |
1053 | ||
621d3121 | 1054 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1055 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1056 | /* | |
1057 | * Queue overflow, abort. We may abort if the | |
1058 | * signal was rt and sent by user using something | |
1059 | * other than kill(). | |
1060 | */ | |
6c303d3a ON |
1061 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1062 | ret = -EAGAIN; | |
1063 | goto ret; | |
ba005e1f MH |
1064 | } else { |
1065 | /* | |
1066 | * This is a silent loss of information. We still | |
1067 | * send the signal, but the *info bits are lost. | |
1068 | */ | |
6c303d3a | 1069 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1070 | } |
1da177e4 LT |
1071 | } |
1072 | ||
1073 | out_set: | |
53c30337 | 1074 | signalfd_notify(t, sig); |
2ca3515a | 1075 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1076 | complete_signal(sig, t, group); |
6c303d3a ON |
1077 | ret: |
1078 | trace_signal_generate(sig, info, t, group, result); | |
1079 | return ret; | |
1da177e4 LT |
1080 | } |
1081 | ||
7978b567 SB |
1082 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1083 | int group) | |
1084 | { | |
921cf9f6 SB |
1085 | int from_ancestor_ns = 0; |
1086 | ||
1087 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1088 | from_ancestor_ns = si_fromuser(info) && |
1089 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1090 | #endif |
1091 | ||
1092 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1093 | } |
1094 | ||
4aaefee5 | 1095 | static void print_fatal_signal(int signr) |
45807a1d | 1096 | { |
4aaefee5 | 1097 | struct pt_regs *regs = signal_pt_regs(); |
747800ef | 1098 | pr_info("potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1099 | |
ca5cd877 | 1100 | #if defined(__i386__) && !defined(__arch_um__) |
747800ef | 1101 | pr_info("code at %08lx: ", regs->ip); |
45807a1d IM |
1102 | { |
1103 | int i; | |
1104 | for (i = 0; i < 16; i++) { | |
1105 | unsigned char insn; | |
1106 | ||
b45c6e76 AK |
1107 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1108 | break; | |
747800ef | 1109 | pr_cont("%02x ", insn); |
45807a1d IM |
1110 | } |
1111 | } | |
747800ef | 1112 | pr_cont("\n"); |
45807a1d | 1113 | #endif |
3a9f84d3 | 1114 | preempt_disable(); |
45807a1d | 1115 | show_regs(regs); |
3a9f84d3 | 1116 | preempt_enable(); |
45807a1d IM |
1117 | } |
1118 | ||
1119 | static int __init setup_print_fatal_signals(char *str) | |
1120 | { | |
1121 | get_option (&str, &print_fatal_signals); | |
1122 | ||
1123 | return 1; | |
1124 | } | |
1125 | ||
1126 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1127 | |
4cd4b6d4 PE |
1128 | int |
1129 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1130 | { | |
1131 | return send_signal(sig, info, p, 1); | |
1132 | } | |
1133 | ||
1da177e4 LT |
1134 | static int |
1135 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1136 | { | |
4cd4b6d4 | 1137 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1138 | } |
1139 | ||
4a30debf ON |
1140 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1141 | bool group) | |
1142 | { | |
1143 | unsigned long flags; | |
1144 | int ret = -ESRCH; | |
1145 | ||
1146 | if (lock_task_sighand(p, &flags)) { | |
1147 | ret = send_signal(sig, info, p, group); | |
1148 | unlock_task_sighand(p, &flags); | |
1149 | } | |
1150 | ||
1151 | return ret; | |
1152 | } | |
1153 | ||
1da177e4 LT |
1154 | /* |
1155 | * Force a signal that the process can't ignore: if necessary | |
1156 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1157 | * |
1158 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1159 | * since we do not want to have a signal handler that was blocked | |
1160 | * be invoked when user space had explicitly blocked it. | |
1161 | * | |
80fe728d ON |
1162 | * We don't want to have recursive SIGSEGV's etc, for example, |
1163 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1164 | */ |
1da177e4 LT |
1165 | int |
1166 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1167 | { | |
1168 | unsigned long int flags; | |
ae74c3b6 LT |
1169 | int ret, blocked, ignored; |
1170 | struct k_sigaction *action; | |
1da177e4 LT |
1171 | |
1172 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1173 | action = &t->sighand->action[sig-1]; |
1174 | ignored = action->sa.sa_handler == SIG_IGN; | |
1175 | blocked = sigismember(&t->blocked, sig); | |
1176 | if (blocked || ignored) { | |
1177 | action->sa.sa_handler = SIG_DFL; | |
1178 | if (blocked) { | |
1179 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1180 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1181 | } |
1da177e4 | 1182 | } |
80fe728d ON |
1183 | if (action->sa.sa_handler == SIG_DFL) |
1184 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1185 | ret = specific_send_sig_info(sig, info, t); |
1186 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1187 | ||
1188 | return ret; | |
1189 | } | |
1190 | ||
1da177e4 LT |
1191 | /* |
1192 | * Nuke all other threads in the group. | |
1193 | */ | |
09faef11 | 1194 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1195 | { |
09faef11 ON |
1196 | struct task_struct *t = p; |
1197 | int count = 0; | |
1da177e4 | 1198 | |
1da177e4 LT |
1199 | p->signal->group_stop_count = 0; |
1200 | ||
09faef11 | 1201 | while_each_thread(p, t) { |
6dfca329 | 1202 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1203 | count++; |
1204 | ||
1205 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1206 | if (t->exit_state) |
1207 | continue; | |
1da177e4 | 1208 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1209 | signal_wake_up(t, 1); |
1210 | } | |
09faef11 ON |
1211 | |
1212 | return count; | |
1da177e4 LT |
1213 | } |
1214 | ||
b8ed374e NK |
1215 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1216 | unsigned long *flags) | |
f63ee72e ON |
1217 | { |
1218 | struct sighand_struct *sighand; | |
1219 | ||
1220 | for (;;) { | |
c41247e1 PM |
1221 | /* |
1222 | * Disable interrupts early to avoid deadlocks. | |
1223 | * See rcu_read_unlock() comment header for details. | |
1224 | */ | |
a841796f PM |
1225 | local_irq_save(*flags); |
1226 | rcu_read_lock(); | |
f63ee72e | 1227 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1228 | if (unlikely(sighand == NULL)) { |
1229 | rcu_read_unlock(); | |
1230 | local_irq_restore(*flags); | |
f63ee72e | 1231 | break; |
a841796f | 1232 | } |
392809b2 ON |
1233 | /* |
1234 | * This sighand can be already freed and even reused, but | |
1235 | * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which | |
1236 | * initializes ->siglock: this slab can't go away, it has | |
1237 | * the same object type, ->siglock can't be reinitialized. | |
1238 | * | |
1239 | * We need to ensure that tsk->sighand is still the same | |
1240 | * after we take the lock, we can race with de_thread() or | |
1241 | * __exit_signal(). In the latter case the next iteration | |
1242 | * must see ->sighand == NULL. | |
1243 | */ | |
a841796f PM |
1244 | spin_lock(&sighand->siglock); |
1245 | if (likely(sighand == tsk->sighand)) { | |
1246 | rcu_read_unlock(); | |
f63ee72e | 1247 | break; |
a841796f PM |
1248 | } |
1249 | spin_unlock(&sighand->siglock); | |
1250 | rcu_read_unlock(); | |
1251 | local_irq_restore(*flags); | |
f63ee72e ON |
1252 | } |
1253 | ||
1254 | return sighand; | |
1255 | } | |
1256 | ||
c69e8d9c DH |
1257 | /* |
1258 | * send signal info to all the members of a group | |
c69e8d9c | 1259 | */ |
1da177e4 LT |
1260 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1261 | { | |
694f690d DH |
1262 | int ret; |
1263 | ||
1264 | rcu_read_lock(); | |
1265 | ret = check_kill_permission(sig, info, p); | |
1266 | rcu_read_unlock(); | |
f63ee72e | 1267 | |
4a30debf ON |
1268 | if (!ret && sig) |
1269 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1270 | |
1271 | return ret; | |
1272 | } | |
1273 | ||
1274 | /* | |
146a505d | 1275 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1276 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1277 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1278 | */ |
c4b92fc1 | 1279 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1280 | { |
1281 | struct task_struct *p = NULL; | |
1282 | int retval, success; | |
1283 | ||
1da177e4 LT |
1284 | success = 0; |
1285 | retval = -ESRCH; | |
c4b92fc1 | 1286 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1287 | int err = group_send_sig_info(sig, info, p); |
1288 | success |= !err; | |
1289 | retval = err; | |
c4b92fc1 | 1290 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1291 | return success ? 0 : retval; |
1292 | } | |
1293 | ||
c4b92fc1 | 1294 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1295 | { |
d36174bc | 1296 | int error = -ESRCH; |
1da177e4 LT |
1297 | struct task_struct *p; |
1298 | ||
eca1a089 PM |
1299 | for (;;) { |
1300 | rcu_read_lock(); | |
1301 | p = pid_task(pid, PIDTYPE_PID); | |
1302 | if (p) | |
1303 | error = group_send_sig_info(sig, info, p); | |
1304 | rcu_read_unlock(); | |
1305 | if (likely(!p || error != -ESRCH)) | |
1306 | return error; | |
6ca25b55 | 1307 | |
eca1a089 PM |
1308 | /* |
1309 | * The task was unhashed in between, try again. If it | |
1310 | * is dead, pid_task() will return NULL, if we race with | |
1311 | * de_thread() it will find the new leader. | |
1312 | */ | |
1313 | } | |
1da177e4 LT |
1314 | } |
1315 | ||
5aba085e | 1316 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1317 | { |
1318 | int error; | |
1319 | rcu_read_lock(); | |
b488893a | 1320 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1321 | rcu_read_unlock(); |
1322 | return error; | |
1323 | } | |
1324 | ||
d178bc3a SH |
1325 | static int kill_as_cred_perm(const struct cred *cred, |
1326 | struct task_struct *target) | |
1327 | { | |
1328 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1329 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1330 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1331 | return 0; |
1332 | return 1; | |
1333 | } | |
1334 | ||
2425c08b | 1335 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1336 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1337 | const struct cred *cred, u32 secid) | |
46113830 HW |
1338 | { |
1339 | int ret = -EINVAL; | |
1340 | struct task_struct *p; | |
14d8c9f3 | 1341 | unsigned long flags; |
46113830 HW |
1342 | |
1343 | if (!valid_signal(sig)) | |
1344 | return ret; | |
1345 | ||
14d8c9f3 | 1346 | rcu_read_lock(); |
2425c08b | 1347 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1348 | if (!p) { |
1349 | ret = -ESRCH; | |
1350 | goto out_unlock; | |
1351 | } | |
d178bc3a | 1352 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1353 | ret = -EPERM; |
1354 | goto out_unlock; | |
1355 | } | |
8f95dc58 DQ |
1356 | ret = security_task_kill(p, info, sig, secid); |
1357 | if (ret) | |
1358 | goto out_unlock; | |
14d8c9f3 TG |
1359 | |
1360 | if (sig) { | |
1361 | if (lock_task_sighand(p, &flags)) { | |
1362 | ret = __send_signal(sig, info, p, 1, 0); | |
1363 | unlock_task_sighand(p, &flags); | |
1364 | } else | |
1365 | ret = -ESRCH; | |
46113830 HW |
1366 | } |
1367 | out_unlock: | |
14d8c9f3 | 1368 | rcu_read_unlock(); |
46113830 HW |
1369 | return ret; |
1370 | } | |
d178bc3a | 1371 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1372 | |
1373 | /* | |
1374 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1375 | * | |
1376 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1377 | * is probably wrong. Should make it like BSD or SYSV. | |
1378 | */ | |
1379 | ||
bc64efd2 | 1380 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1381 | { |
8d42db18 | 1382 | int ret; |
d5df763b PE |
1383 | |
1384 | if (pid > 0) { | |
1385 | rcu_read_lock(); | |
1386 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1387 | rcu_read_unlock(); | |
1388 | return ret; | |
1389 | } | |
1390 | ||
1391 | read_lock(&tasklist_lock); | |
1392 | if (pid != -1) { | |
1393 | ret = __kill_pgrp_info(sig, info, | |
1394 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1395 | } else { | |
1da177e4 LT |
1396 | int retval = 0, count = 0; |
1397 | struct task_struct * p; | |
1398 | ||
1da177e4 | 1399 | for_each_process(p) { |
d25141a8 SB |
1400 | if (task_pid_vnr(p) > 1 && |
1401 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1402 | int err = group_send_sig_info(sig, info, p); |
1403 | ++count; | |
1404 | if (err != -EPERM) | |
1405 | retval = err; | |
1406 | } | |
1407 | } | |
8d42db18 | 1408 | ret = count ? retval : -ESRCH; |
1da177e4 | 1409 | } |
d5df763b PE |
1410 | read_unlock(&tasklist_lock); |
1411 | ||
8d42db18 | 1412 | return ret; |
1da177e4 LT |
1413 | } |
1414 | ||
1415 | /* | |
1416 | * These are for backward compatibility with the rest of the kernel source. | |
1417 | */ | |
1418 | ||
5aba085e | 1419 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1420 | { |
1da177e4 LT |
1421 | /* |
1422 | * Make sure legacy kernel users don't send in bad values | |
1423 | * (normal paths check this in check_kill_permission). | |
1424 | */ | |
7ed20e1a | 1425 | if (!valid_signal(sig)) |
1da177e4 LT |
1426 | return -EINVAL; |
1427 | ||
4a30debf | 1428 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1429 | } |
1430 | ||
b67a1b9e ON |
1431 | #define __si_special(priv) \ |
1432 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1433 | ||
1da177e4 LT |
1434 | int |
1435 | send_sig(int sig, struct task_struct *p, int priv) | |
1436 | { | |
b67a1b9e | 1437 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1438 | } |
1439 | ||
1da177e4 LT |
1440 | void |
1441 | force_sig(int sig, struct task_struct *p) | |
1442 | { | |
b67a1b9e | 1443 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1444 | } |
1445 | ||
1446 | /* | |
1447 | * When things go south during signal handling, we | |
1448 | * will force a SIGSEGV. And if the signal that caused | |
1449 | * the problem was already a SIGSEGV, we'll want to | |
1450 | * make sure we don't even try to deliver the signal.. | |
1451 | */ | |
1452 | int | |
1453 | force_sigsegv(int sig, struct task_struct *p) | |
1454 | { | |
1455 | if (sig == SIGSEGV) { | |
1456 | unsigned long flags; | |
1457 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1458 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1459 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1460 | } | |
1461 | force_sig(SIGSEGV, p); | |
1462 | return 0; | |
1463 | } | |
1464 | ||
c4b92fc1 EB |
1465 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1466 | { | |
146a505d PE |
1467 | int ret; |
1468 | ||
1469 | read_lock(&tasklist_lock); | |
1470 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1471 | read_unlock(&tasklist_lock); | |
1472 | ||
1473 | return ret; | |
c4b92fc1 EB |
1474 | } |
1475 | EXPORT_SYMBOL(kill_pgrp); | |
1476 | ||
1477 | int kill_pid(struct pid *pid, int sig, int priv) | |
1478 | { | |
1479 | return kill_pid_info(sig, __si_special(priv), pid); | |
1480 | } | |
1481 | EXPORT_SYMBOL(kill_pid); | |
1482 | ||
1da177e4 LT |
1483 | /* |
1484 | * These functions support sending signals using preallocated sigqueue | |
1485 | * structures. This is needed "because realtime applications cannot | |
1486 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1487 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1488 | * we allocate the sigqueue structure from the timer_create. If this |
1489 | * allocation fails we are able to report the failure to the application | |
1490 | * with an EAGAIN error. | |
1491 | */ | |
1da177e4 LT |
1492 | struct sigqueue *sigqueue_alloc(void) |
1493 | { | |
f84d49b2 | 1494 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1495 | |
f84d49b2 | 1496 | if (q) |
1da177e4 | 1497 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1498 | |
1499 | return q; | |
1da177e4 LT |
1500 | } |
1501 | ||
1502 | void sigqueue_free(struct sigqueue *q) | |
1503 | { | |
1504 | unsigned long flags; | |
60187d27 ON |
1505 | spinlock_t *lock = ¤t->sighand->siglock; |
1506 | ||
1da177e4 LT |
1507 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1508 | /* | |
c8e85b4f ON |
1509 | * We must hold ->siglock while testing q->list |
1510 | * to serialize with collect_signal() or with | |
da7978b0 | 1511 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1512 | */ |
60187d27 | 1513 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1514 | q->flags &= ~SIGQUEUE_PREALLOC; |
1515 | /* | |
1516 | * If it is queued it will be freed when dequeued, | |
1517 | * like the "regular" sigqueue. | |
1518 | */ | |
60187d27 | 1519 | if (!list_empty(&q->list)) |
c8e85b4f | 1520 | q = NULL; |
60187d27 ON |
1521 | spin_unlock_irqrestore(lock, flags); |
1522 | ||
c8e85b4f ON |
1523 | if (q) |
1524 | __sigqueue_free(q); | |
1da177e4 LT |
1525 | } |
1526 | ||
ac5c2153 | 1527 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1528 | { |
e62e6650 | 1529 | int sig = q->info.si_signo; |
2ca3515a | 1530 | struct sigpending *pending; |
e62e6650 | 1531 | unsigned long flags; |
163566f6 | 1532 | int ret, result; |
2ca3515a | 1533 | |
4cd4b6d4 | 1534 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1535 | |
1536 | ret = -1; | |
1537 | if (!likely(lock_task_sighand(t, &flags))) | |
1538 | goto ret; | |
1539 | ||
7e695a5e | 1540 | ret = 1; /* the signal is ignored */ |
163566f6 | 1541 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1542 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1543 | goto out; |
1544 | ||
1545 | ret = 0; | |
9e3bd6c3 PE |
1546 | if (unlikely(!list_empty(&q->list))) { |
1547 | /* | |
1548 | * If an SI_TIMER entry is already queue just increment | |
1549 | * the overrun count. | |
1550 | */ | |
9e3bd6c3 PE |
1551 | BUG_ON(q->info.si_code != SI_TIMER); |
1552 | q->info.si_overrun++; | |
163566f6 | 1553 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1554 | goto out; |
9e3bd6c3 | 1555 | } |
ba661292 | 1556 | q->info.si_overrun = 0; |
9e3bd6c3 | 1557 | |
9e3bd6c3 | 1558 | signalfd_notify(t, sig); |
2ca3515a | 1559 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1560 | list_add_tail(&q->list, &pending->list); |
1561 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1562 | complete_signal(sig, t, group); |
163566f6 | 1563 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1564 | out: |
163566f6 | 1565 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1566 | unlock_task_sighand(t, &flags); |
1567 | ret: | |
1568 | return ret; | |
9e3bd6c3 PE |
1569 | } |
1570 | ||
1da177e4 LT |
1571 | /* |
1572 | * Let a parent know about the death of a child. | |
1573 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1574 | * |
53c8f9f1 ON |
1575 | * Returns true if our parent ignored us and so we've switched to |
1576 | * self-reaping. | |
1da177e4 | 1577 | */ |
53c8f9f1 | 1578 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1579 | { |
1580 | struct siginfo info; | |
1581 | unsigned long flags; | |
1582 | struct sighand_struct *psig; | |
53c8f9f1 | 1583 | bool autoreap = false; |
6fac4829 | 1584 | cputime_t utime, stime; |
1da177e4 LT |
1585 | |
1586 | BUG_ON(sig == -1); | |
1587 | ||
1588 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1589 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1590 | |
d21142ec | 1591 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1592 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1593 | ||
b6e238dc ON |
1594 | if (sig != SIGCHLD) { |
1595 | /* | |
1596 | * This is only possible if parent == real_parent. | |
1597 | * Check if it has changed security domain. | |
1598 | */ | |
1599 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1600 | sig = SIGCHLD; | |
1601 | } | |
1602 | ||
1da177e4 LT |
1603 | info.si_signo = sig; |
1604 | info.si_errno = 0; | |
b488893a | 1605 | /* |
32084504 EB |
1606 | * We are under tasklist_lock here so our parent is tied to |
1607 | * us and cannot change. | |
b488893a | 1608 | * |
32084504 EB |
1609 | * task_active_pid_ns will always return the same pid namespace |
1610 | * until a task passes through release_task. | |
b488893a PE |
1611 | * |
1612 | * write_lock() currently calls preempt_disable() which is the | |
1613 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1614 | * correct to rely on this | |
1615 | */ | |
1616 | rcu_read_lock(); | |
32084504 | 1617 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1618 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1619 | task_uid(tsk)); | |
b488893a PE |
1620 | rcu_read_unlock(); |
1621 | ||
6fac4829 FW |
1622 | task_cputime(tsk, &utime, &stime); |
1623 | info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime); | |
1624 | info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1625 | |
1626 | info.si_status = tsk->exit_code & 0x7f; | |
1627 | if (tsk->exit_code & 0x80) | |
1628 | info.si_code = CLD_DUMPED; | |
1629 | else if (tsk->exit_code & 0x7f) | |
1630 | info.si_code = CLD_KILLED; | |
1631 | else { | |
1632 | info.si_code = CLD_EXITED; | |
1633 | info.si_status = tsk->exit_code >> 8; | |
1634 | } | |
1635 | ||
1636 | psig = tsk->parent->sighand; | |
1637 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1638 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1639 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1640 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1641 | /* | |
1642 | * We are exiting and our parent doesn't care. POSIX.1 | |
1643 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1644 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1645 | * automatically and not left for our parent's wait4 call. | |
1646 | * Rather than having the parent do it as a magic kind of | |
1647 | * signal handler, we just set this to tell do_exit that we | |
1648 | * can be cleaned up without becoming a zombie. Note that | |
1649 | * we still call __wake_up_parent in this case, because a | |
1650 | * blocked sys_wait4 might now return -ECHILD. | |
1651 | * | |
1652 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1653 | * is implementation-defined: we do (if you don't want | |
1654 | * it, just use SIG_IGN instead). | |
1655 | */ | |
53c8f9f1 | 1656 | autoreap = true; |
1da177e4 | 1657 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1658 | sig = 0; |
1da177e4 | 1659 | } |
53c8f9f1 | 1660 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1661 | __group_send_sig_info(sig, &info, tsk->parent); |
1662 | __wake_up_parent(tsk, tsk->parent); | |
1663 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1664 | |
53c8f9f1 | 1665 | return autoreap; |
1da177e4 LT |
1666 | } |
1667 | ||
75b95953 TH |
1668 | /** |
1669 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1670 | * @tsk: task reporting the state change | |
1671 | * @for_ptracer: the notification is for ptracer | |
1672 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1673 | * | |
1674 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1675 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1676 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1677 | * | |
1678 | * CONTEXT: | |
1679 | * Must be called with tasklist_lock at least read locked. | |
1680 | */ | |
1681 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1682 | bool for_ptracer, int why) | |
1da177e4 LT |
1683 | { |
1684 | struct siginfo info; | |
1685 | unsigned long flags; | |
bc505a47 | 1686 | struct task_struct *parent; |
1da177e4 | 1687 | struct sighand_struct *sighand; |
6fac4829 | 1688 | cputime_t utime, stime; |
1da177e4 | 1689 | |
75b95953 | 1690 | if (for_ptracer) { |
bc505a47 | 1691 | parent = tsk->parent; |
75b95953 | 1692 | } else { |
bc505a47 ON |
1693 | tsk = tsk->group_leader; |
1694 | parent = tsk->real_parent; | |
1695 | } | |
1696 | ||
1da177e4 LT |
1697 | info.si_signo = SIGCHLD; |
1698 | info.si_errno = 0; | |
b488893a | 1699 | /* |
5aba085e | 1700 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1701 | */ |
1702 | rcu_read_lock(); | |
17cf22c3 | 1703 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1704 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1705 | rcu_read_unlock(); |
1706 | ||
6fac4829 FW |
1707 | task_cputime(tsk, &utime, &stime); |
1708 | info.si_utime = cputime_to_clock_t(utime); | |
1709 | info.si_stime = cputime_to_clock_t(stime); | |
1da177e4 LT |
1710 | |
1711 | info.si_code = why; | |
1712 | switch (why) { | |
1713 | case CLD_CONTINUED: | |
1714 | info.si_status = SIGCONT; | |
1715 | break; | |
1716 | case CLD_STOPPED: | |
1717 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1718 | break; | |
1719 | case CLD_TRAPPED: | |
1720 | info.si_status = tsk->exit_code & 0x7f; | |
1721 | break; | |
1722 | default: | |
1723 | BUG(); | |
1724 | } | |
1725 | ||
1726 | sighand = parent->sighand; | |
1727 | spin_lock_irqsave(&sighand->siglock, flags); | |
1728 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1729 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1730 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1731 | /* | |
1732 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1733 | */ | |
1734 | __wake_up_parent(tsk, parent); | |
1735 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1736 | } | |
1737 | ||
d5f70c00 ON |
1738 | static inline int may_ptrace_stop(void) |
1739 | { | |
d21142ec | 1740 | if (!likely(current->ptrace)) |
d5f70c00 | 1741 | return 0; |
d5f70c00 ON |
1742 | /* |
1743 | * Are we in the middle of do_coredump? | |
1744 | * If so and our tracer is also part of the coredump stopping | |
1745 | * is a deadlock situation, and pointless because our tracer | |
1746 | * is dead so don't allow us to stop. | |
1747 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1748 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1749 | * is safe to enter schedule(). |
9899d11f ON |
1750 | * |
1751 | * This is almost outdated, a task with the pending SIGKILL can't | |
1752 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1753 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1754 | */ |
999d9fc1 | 1755 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1756 | unlikely(current->mm == current->parent->mm)) |
1757 | return 0; | |
1758 | ||
1759 | return 1; | |
1760 | } | |
1761 | ||
1a669c2f | 1762 | /* |
5aba085e | 1763 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1764 | * Called with the siglock held. |
1765 | */ | |
1766 | static int sigkill_pending(struct task_struct *tsk) | |
1767 | { | |
3d749b9e ON |
1768 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1769 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1770 | } |
1771 | ||
1da177e4 LT |
1772 | /* |
1773 | * This must be called with current->sighand->siglock held. | |
1774 | * | |
1775 | * This should be the path for all ptrace stops. | |
1776 | * We always set current->last_siginfo while stopped here. | |
1777 | * That makes it a way to test a stopped process for | |
1778 | * being ptrace-stopped vs being job-control-stopped. | |
1779 | * | |
20686a30 ON |
1780 | * If we actually decide not to stop at all because the tracer |
1781 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1782 | */ |
fe1bc6a0 | 1783 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1784 | __releases(¤t->sighand->siglock) |
1785 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1786 | { |
ceb6bd67 TH |
1787 | bool gstop_done = false; |
1788 | ||
1a669c2f RM |
1789 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1790 | /* | |
1791 | * The arch code has something special to do before a | |
1792 | * ptrace stop. This is allowed to block, e.g. for faults | |
1793 | * on user stack pages. We can't keep the siglock while | |
1794 | * calling arch_ptrace_stop, so we must release it now. | |
1795 | * To preserve proper semantics, we must do this before | |
1796 | * any signal bookkeeping like checking group_stop_count. | |
1797 | * Meanwhile, a SIGKILL could come in before we retake the | |
1798 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1799 | * So after regaining the lock, we must check for SIGKILL. | |
1800 | */ | |
1801 | spin_unlock_irq(¤t->sighand->siglock); | |
1802 | arch_ptrace_stop(exit_code, info); | |
1803 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1804 | if (sigkill_pending(current)) |
1805 | return; | |
1a669c2f RM |
1806 | } |
1807 | ||
1da177e4 | 1808 | /* |
81be24b8 TH |
1809 | * We're committing to trapping. TRACED should be visible before |
1810 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1811 | * Also, transition to TRACED and updates to ->jobctl should be | |
1812 | * atomic with respect to siglock and should be done after the arch | |
1813 | * hook as siglock is released and regrabbed across it. | |
1da177e4 | 1814 | */ |
81be24b8 | 1815 | set_current_state(TASK_TRACED); |
1da177e4 LT |
1816 | |
1817 | current->last_siginfo = info; | |
1818 | current->exit_code = exit_code; | |
1819 | ||
d79fdd6d | 1820 | /* |
0ae8ce1c TH |
1821 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1822 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1823 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1824 | * could be clear now. We act as if SIGCONT is received after | |
1825 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1826 | */ |
a8f072c1 | 1827 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1828 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1829 | |
fb1d910c | 1830 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1831 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1832 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1833 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1834 | |
81be24b8 | 1835 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1836 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1837 | |
1da177e4 LT |
1838 | spin_unlock_irq(¤t->sighand->siglock); |
1839 | read_lock(&tasklist_lock); | |
3d749b9e | 1840 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1841 | /* |
1842 | * Notify parents of the stop. | |
1843 | * | |
1844 | * While ptraced, there are two parents - the ptracer and | |
1845 | * the real_parent of the group_leader. The ptracer should | |
1846 | * know about every stop while the real parent is only | |
1847 | * interested in the completion of group stop. The states | |
1848 | * for the two don't interact with each other. Notify | |
1849 | * separately unless they're gonna be duplicates. | |
1850 | */ | |
1851 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1852 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1853 | do_notify_parent_cldstop(current, false, why); |
1854 | ||
53da1d94 MS |
1855 | /* |
1856 | * Don't want to allow preemption here, because | |
1857 | * sys_ptrace() needs this task to be inactive. | |
1858 | * | |
1859 | * XXX: implement read_unlock_no_resched(). | |
1860 | */ | |
1861 | preempt_disable(); | |
1da177e4 | 1862 | read_unlock(&tasklist_lock); |
53da1d94 | 1863 | preempt_enable_no_resched(); |
5d8f72b5 | 1864 | freezable_schedule(); |
1da177e4 LT |
1865 | } else { |
1866 | /* | |
1867 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1868 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1869 | * |
1870 | * If @gstop_done, the ptracer went away between group stop | |
1871 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1872 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1873 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1874 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1875 | */ |
ceb6bd67 TH |
1876 | if (gstop_done) |
1877 | do_notify_parent_cldstop(current, false, why); | |
1878 | ||
9899d11f | 1879 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 1880 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1881 | if (clear_code) |
1882 | current->exit_code = 0; | |
6405f7f4 | 1883 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1884 | } |
1885 | ||
1886 | /* | |
1887 | * We are back. Now reacquire the siglock before touching | |
1888 | * last_siginfo, so that we are sure to have synchronized with | |
1889 | * any signal-sending on another CPU that wants to examine it. | |
1890 | */ | |
1891 | spin_lock_irq(¤t->sighand->siglock); | |
1892 | current->last_siginfo = NULL; | |
1893 | ||
544b2c91 TH |
1894 | /* LISTENING can be set only during STOP traps, clear it */ |
1895 | current->jobctl &= ~JOBCTL_LISTENING; | |
1896 | ||
1da177e4 LT |
1897 | /* |
1898 | * Queued signals ignored us while we were stopped for tracing. | |
1899 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1900 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1901 | */ |
b74d0deb | 1902 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1903 | } |
1904 | ||
3544d72a | 1905 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1906 | { |
1907 | siginfo_t info; | |
1908 | ||
1da177e4 | 1909 | memset(&info, 0, sizeof info); |
3544d72a | 1910 | info.si_signo = signr; |
1da177e4 | 1911 | info.si_code = exit_code; |
b488893a | 1912 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1913 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1914 | |
1915 | /* Let the debugger run. */ | |
3544d72a TH |
1916 | ptrace_stop(exit_code, why, 1, &info); |
1917 | } | |
1918 | ||
1919 | void ptrace_notify(int exit_code) | |
1920 | { | |
1921 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
1922 | if (unlikely(current->task_works)) |
1923 | task_work_run(); | |
3544d72a | 1924 | |
1da177e4 | 1925 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1926 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1927 | spin_unlock_irq(¤t->sighand->siglock); |
1928 | } | |
1929 | ||
73ddff2b TH |
1930 | /** |
1931 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1932 | * @signr: signr causing group stop if initiating | |
1933 | * | |
1934 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1935 | * and participate in it. If already set, participate in the existing | |
1936 | * group stop. If participated in a group stop (and thus slept), %true is | |
1937 | * returned with siglock released. | |
1938 | * | |
1939 | * If ptraced, this function doesn't handle stop itself. Instead, | |
1940 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
1941 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
1942 | * places afterwards. | |
1943 | * | |
1944 | * CONTEXT: | |
1945 | * Must be called with @current->sighand->siglock held, which is released | |
1946 | * on %true return. | |
1947 | * | |
1948 | * RETURNS: | |
1949 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
1950 | * %true if participated in group stop. | |
1da177e4 | 1951 | */ |
73ddff2b TH |
1952 | static bool do_signal_stop(int signr) |
1953 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
1954 | { |
1955 | struct signal_struct *sig = current->signal; | |
1da177e4 | 1956 | |
a8f072c1 | 1957 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
b76808e6 | 1958 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
f558b7e4 ON |
1959 | struct task_struct *t; |
1960 | ||
a8f072c1 TH |
1961 | /* signr will be recorded in task->jobctl for retries */ |
1962 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 1963 | |
a8f072c1 | 1964 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 1965 | unlikely(signal_group_exit(sig))) |
73ddff2b | 1966 | return false; |
1da177e4 | 1967 | /* |
408a37de TH |
1968 | * There is no group stop already in progress. We must |
1969 | * initiate one now. | |
1970 | * | |
1971 | * While ptraced, a task may be resumed while group stop is | |
1972 | * still in effect and then receive a stop signal and | |
1973 | * initiate another group stop. This deviates from the | |
1974 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
1975 | * cause two group stops when !ptraced. That is why we |
1976 | * also check !task_is_stopped(t) below. | |
408a37de TH |
1977 | * |
1978 | * The condition can be distinguished by testing whether | |
1979 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
1980 | * group_exit_code in such case. | |
1981 | * | |
1982 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
1983 | * an intervening stop signal is required to cause two | |
1984 | * continued events regardless of ptrace. | |
1da177e4 | 1985 | */ |
408a37de TH |
1986 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
1987 | sig->group_exit_code = signr; | |
1da177e4 | 1988 | |
7dd3db54 TH |
1989 | sig->group_stop_count = 0; |
1990 | ||
1991 | if (task_set_jobctl_pending(current, signr | gstop)) | |
1992 | sig->group_stop_count++; | |
1da177e4 | 1993 | |
8d38f203 ON |
1994 | t = current; |
1995 | while_each_thread(current, t) { | |
1da177e4 | 1996 | /* |
a122b341 ON |
1997 | * Setting state to TASK_STOPPED for a group |
1998 | * stop is always done with the siglock held, | |
1999 | * so this check has no races. | |
1da177e4 | 2000 | */ |
7dd3db54 TH |
2001 | if (!task_is_stopped(t) && |
2002 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2003 | sig->group_stop_count++; |
fb1d910c TH |
2004 | if (likely(!(t->ptrace & PT_SEIZED))) |
2005 | signal_wake_up(t, 0); | |
2006 | else | |
2007 | ptrace_trap_notify(t); | |
a122b341 | 2008 | } |
d79fdd6d | 2009 | } |
1da177e4 | 2010 | } |
73ddff2b | 2011 | |
d21142ec | 2012 | if (likely(!current->ptrace)) { |
5224fa36 | 2013 | int notify = 0; |
1da177e4 | 2014 | |
5224fa36 TH |
2015 | /* |
2016 | * If there are no other threads in the group, or if there | |
2017 | * is a group stop in progress and we are the last to stop, | |
2018 | * report to the parent. | |
2019 | */ | |
2020 | if (task_participate_group_stop(current)) | |
2021 | notify = CLD_STOPPED; | |
2022 | ||
ae6d2ed7 | 2023 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
2024 | spin_unlock_irq(¤t->sighand->siglock); |
2025 | ||
62bcf9d9 TH |
2026 | /* |
2027 | * Notify the parent of the group stop completion. Because | |
2028 | * we're not holding either the siglock or tasklist_lock | |
2029 | * here, ptracer may attach inbetween; however, this is for | |
2030 | * group stop and should always be delivered to the real | |
2031 | * parent of the group leader. The new ptracer will get | |
2032 | * its notification when this task transitions into | |
2033 | * TASK_TRACED. | |
2034 | */ | |
5224fa36 TH |
2035 | if (notify) { |
2036 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2037 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2038 | read_unlock(&tasklist_lock); |
2039 | } | |
2040 | ||
2041 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
5d8f72b5 | 2042 | freezable_schedule(); |
73ddff2b | 2043 | return true; |
d79fdd6d | 2044 | } else { |
73ddff2b TH |
2045 | /* |
2046 | * While ptraced, group stop is handled by STOP trap. | |
2047 | * Schedule it and let the caller deal with it. | |
2048 | */ | |
2049 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2050 | return false; | |
ae6d2ed7 | 2051 | } |
73ddff2b | 2052 | } |
1da177e4 | 2053 | |
73ddff2b TH |
2054 | /** |
2055 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2056 | * | |
3544d72a TH |
2057 | * When PT_SEIZED, it's used for both group stop and explicit |
2058 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2059 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2060 | * the stop signal; otherwise, %SIGTRAP. | |
2061 | * | |
2062 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2063 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2064 | * |
2065 | * CONTEXT: | |
2066 | * Must be called with @current->sighand->siglock held, which may be | |
2067 | * released and re-acquired before returning with intervening sleep. | |
2068 | */ | |
2069 | static void do_jobctl_trap(void) | |
2070 | { | |
3544d72a | 2071 | struct signal_struct *signal = current->signal; |
73ddff2b | 2072 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2073 | |
3544d72a TH |
2074 | if (current->ptrace & PT_SEIZED) { |
2075 | if (!signal->group_stop_count && | |
2076 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2077 | signr = SIGTRAP; | |
2078 | WARN_ON_ONCE(!signr); | |
2079 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2080 | CLD_STOPPED); | |
2081 | } else { | |
2082 | WARN_ON_ONCE(!signr); | |
2083 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2084 | current->exit_code = 0; | |
ae6d2ed7 | 2085 | } |
1da177e4 LT |
2086 | } |
2087 | ||
94eb22d5 | 2088 | static int ptrace_signal(int signr, siginfo_t *info) |
18c98b65 | 2089 | { |
b7f9591c | 2090 | ptrace_signal_deliver(); |
8a352418 ON |
2091 | /* |
2092 | * We do not check sig_kernel_stop(signr) but set this marker | |
2093 | * unconditionally because we do not know whether debugger will | |
2094 | * change signr. This flag has no meaning unless we are going | |
2095 | * to stop after return from ptrace_stop(). In this case it will | |
2096 | * be checked in do_signal_stop(), we should only stop if it was | |
2097 | * not cleared by SIGCONT while we were sleeping. See also the | |
2098 | * comment in dequeue_signal(). | |
2099 | */ | |
2100 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2101 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2102 | |
2103 | /* We're back. Did the debugger cancel the sig? */ | |
2104 | signr = current->exit_code; | |
2105 | if (signr == 0) | |
2106 | return signr; | |
2107 | ||
2108 | current->exit_code = 0; | |
2109 | ||
5aba085e RD |
2110 | /* |
2111 | * Update the siginfo structure if the signal has | |
2112 | * changed. If the debugger wanted something | |
2113 | * specific in the siginfo structure then it should | |
2114 | * have updated *info via PTRACE_SETSIGINFO. | |
2115 | */ | |
18c98b65 RM |
2116 | if (signr != info->si_signo) { |
2117 | info->si_signo = signr; | |
2118 | info->si_errno = 0; | |
2119 | info->si_code = SI_USER; | |
6b550f94 | 2120 | rcu_read_lock(); |
18c98b65 | 2121 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2122 | info->si_uid = from_kuid_munged(current_user_ns(), |
2123 | task_uid(current->parent)); | |
6b550f94 | 2124 | rcu_read_unlock(); |
18c98b65 RM |
2125 | } |
2126 | ||
2127 | /* If the (new) signal is now blocked, requeue it. */ | |
2128 | if (sigismember(¤t->blocked, signr)) { | |
2129 | specific_send_sig_info(signr, info, current); | |
2130 | signr = 0; | |
2131 | } | |
2132 | ||
2133 | return signr; | |
2134 | } | |
2135 | ||
828b1f65 | 2136 | int get_signal(struct ksignal *ksig) |
1da177e4 | 2137 | { |
f6b76d4f ON |
2138 | struct sighand_struct *sighand = current->sighand; |
2139 | struct signal_struct *signal = current->signal; | |
2140 | int signr; | |
1da177e4 | 2141 | |
f784e8a7 ON |
2142 | if (unlikely(current->task_works)) |
2143 | task_work_run(); | |
72667028 | 2144 | |
0326f5a9 SD |
2145 | if (unlikely(uprobe_deny_signal())) |
2146 | return 0; | |
2147 | ||
13b1c3d4 | 2148 | /* |
5d8f72b5 ON |
2149 | * Do this once, we can't return to user-mode if freezing() == T. |
2150 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2151 | * thus do not need another check after return. | |
13b1c3d4 | 2152 | */ |
fc558a74 RW |
2153 | try_to_freeze(); |
2154 | ||
5d8f72b5 | 2155 | relock: |
f6b76d4f | 2156 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2157 | /* |
2158 | * Every stopped thread goes here after wakeup. Check to see if | |
2159 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2160 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2161 | */ | |
f6b76d4f | 2162 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2163 | int why; |
2164 | ||
2165 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2166 | why = CLD_CONTINUED; | |
2167 | else | |
2168 | why = CLD_STOPPED; | |
2169 | ||
f6b76d4f | 2170 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2171 | |
ae6d2ed7 | 2172 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2173 | |
ceb6bd67 TH |
2174 | /* |
2175 | * Notify the parent that we're continuing. This event is | |
2176 | * always per-process and doesn't make whole lot of sense | |
2177 | * for ptracers, who shouldn't consume the state via | |
2178 | * wait(2) either, but, for backward compatibility, notify | |
2179 | * the ptracer of the group leader too unless it's gonna be | |
2180 | * a duplicate. | |
2181 | */ | |
edf2ed15 | 2182 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2183 | do_notify_parent_cldstop(current, false, why); |
2184 | ||
bb3696da ON |
2185 | if (ptrace_reparented(current->group_leader)) |
2186 | do_notify_parent_cldstop(current->group_leader, | |
2187 | true, why); | |
edf2ed15 | 2188 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2189 | |
e4420551 ON |
2190 | goto relock; |
2191 | } | |
2192 | ||
1da177e4 LT |
2193 | for (;;) { |
2194 | struct k_sigaction *ka; | |
1be53963 | 2195 | |
dd1d6772 TH |
2196 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2197 | do_signal_stop(0)) | |
7bcf6a2c | 2198 | goto relock; |
1be53963 | 2199 | |
73ddff2b TH |
2200 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2201 | do_jobctl_trap(); | |
2202 | spin_unlock_irq(&sighand->siglock); | |
2203 | goto relock; | |
2204 | } | |
1da177e4 | 2205 | |
828b1f65 | 2206 | signr = dequeue_signal(current, ¤t->blocked, &ksig->info); |
7bcf6a2c | 2207 | |
dd1d6772 TH |
2208 | if (!signr) |
2209 | break; /* will return 0 */ | |
7bcf6a2c | 2210 | |
8a352418 | 2211 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
828b1f65 | 2212 | signr = ptrace_signal(signr, &ksig->info); |
dd1d6772 TH |
2213 | if (!signr) |
2214 | continue; | |
1da177e4 LT |
2215 | } |
2216 | ||
dd1d6772 TH |
2217 | ka = &sighand->action[signr-1]; |
2218 | ||
f9d4257e | 2219 | /* Trace actually delivered signals. */ |
828b1f65 | 2220 | trace_signal_deliver(signr, &ksig->info, ka); |
f9d4257e | 2221 | |
1da177e4 LT |
2222 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2223 | continue; | |
2224 | if (ka->sa.sa_handler != SIG_DFL) { | |
2225 | /* Run the handler. */ | |
828b1f65 | 2226 | ksig->ka = *ka; |
1da177e4 LT |
2227 | |
2228 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2229 | ka->sa.sa_handler = SIG_DFL; | |
2230 | ||
2231 | break; /* will return non-zero "signr" value */ | |
2232 | } | |
2233 | ||
2234 | /* | |
2235 | * Now we are doing the default action for this signal. | |
2236 | */ | |
2237 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2238 | continue; | |
2239 | ||
84d73786 | 2240 | /* |
0fbc26a6 | 2241 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2242 | * Container-init gets no signals it doesn't want from same |
2243 | * container. | |
2244 | * | |
2245 | * Note that if global/container-init sees a sig_kernel_only() | |
2246 | * signal here, the signal must have been generated internally | |
2247 | * or must have come from an ancestor namespace. In either | |
2248 | * case, the signal cannot be dropped. | |
84d73786 | 2249 | */ |
fae5fa44 | 2250 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2251 | !sig_kernel_only(signr)) |
1da177e4 LT |
2252 | continue; |
2253 | ||
2254 | if (sig_kernel_stop(signr)) { | |
2255 | /* | |
2256 | * The default action is to stop all threads in | |
2257 | * the thread group. The job control signals | |
2258 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2259 | * always works. Note that siglock needs to be | |
2260 | * dropped during the call to is_orphaned_pgrp() | |
2261 | * because of lock ordering with tasklist_lock. | |
2262 | * This allows an intervening SIGCONT to be posted. | |
2263 | * We need to check for that and bail out if necessary. | |
2264 | */ | |
2265 | if (signr != SIGSTOP) { | |
f6b76d4f | 2266 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2267 | |
2268 | /* signals can be posted during this window */ | |
2269 | ||
3e7cd6c4 | 2270 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2271 | goto relock; |
2272 | ||
f6b76d4f | 2273 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2274 | } |
2275 | ||
828b1f65 | 2276 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
1da177e4 LT |
2277 | /* It released the siglock. */ |
2278 | goto relock; | |
2279 | } | |
2280 | ||
2281 | /* | |
2282 | * We didn't actually stop, due to a race | |
2283 | * with SIGCONT or something like that. | |
2284 | */ | |
2285 | continue; | |
2286 | } | |
2287 | ||
f6b76d4f | 2288 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2289 | |
2290 | /* | |
2291 | * Anything else is fatal, maybe with a core dump. | |
2292 | */ | |
2293 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2294 | |
1da177e4 | 2295 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2296 | if (print_fatal_signals) |
828b1f65 | 2297 | print_fatal_signal(ksig->info.si_signo); |
2b5faa4c | 2298 | proc_coredump_connector(current); |
1da177e4 LT |
2299 | /* |
2300 | * If it was able to dump core, this kills all | |
2301 | * other threads in the group and synchronizes with | |
2302 | * their demise. If we lost the race with another | |
2303 | * thread getting here, it set group_exit_code | |
2304 | * first and our do_group_exit call below will use | |
2305 | * that value and ignore the one we pass it. | |
2306 | */ | |
828b1f65 | 2307 | do_coredump(&ksig->info); |
1da177e4 LT |
2308 | } |
2309 | ||
2310 | /* | |
2311 | * Death signals, no core dump. | |
2312 | */ | |
828b1f65 | 2313 | do_group_exit(ksig->info.si_signo); |
1da177e4 LT |
2314 | /* NOTREACHED */ |
2315 | } | |
f6b76d4f | 2316 | spin_unlock_irq(&sighand->siglock); |
828b1f65 RW |
2317 | |
2318 | ksig->sig = signr; | |
2319 | return ksig->sig > 0; | |
1da177e4 LT |
2320 | } |
2321 | ||
5e6292c0 | 2322 | /** |
efee984c | 2323 | * signal_delivered - |
10b1c7ac | 2324 | * @ksig: kernel signal struct |
efee984c | 2325 | * @stepping: nonzero if debugger single-step or block-step in use |
5e6292c0 | 2326 | * |
e227867f | 2327 | * This function should be called when a signal has successfully been |
10b1c7ac | 2328 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
efee984c | 2329 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER |
10b1c7ac | 2330 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
5e6292c0 | 2331 | */ |
10b1c7ac | 2332 | static void signal_delivered(struct ksignal *ksig, int stepping) |
5e6292c0 MF |
2333 | { |
2334 | sigset_t blocked; | |
2335 | ||
a610d6e6 AV |
2336 | /* A signal was successfully delivered, and the |
2337 | saved sigmask was stored on the signal frame, | |
2338 | and will be restored by sigreturn. So we can | |
2339 | simply clear the restore sigmask flag. */ | |
2340 | clear_restore_sigmask(); | |
2341 | ||
10b1c7ac RW |
2342 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
2343 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) | |
2344 | sigaddset(&blocked, ksig->sig); | |
5e6292c0 | 2345 | set_current_blocked(&blocked); |
df5601f9 | 2346 | tracehook_signal_handler(stepping); |
5e6292c0 MF |
2347 | } |
2348 | ||
2ce5da17 AV |
2349 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2350 | { | |
2351 | if (failed) | |
2352 | force_sigsegv(ksig->sig, current); | |
2353 | else | |
10b1c7ac | 2354 | signal_delivered(ksig, stepping); |
2ce5da17 AV |
2355 | } |
2356 | ||
0edceb7b ON |
2357 | /* |
2358 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2359 | * group-wide signal. Other threads should be notified now to take |
2360 | * the shared signals in @which since we will not. | |
0edceb7b | 2361 | */ |
f646e227 | 2362 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2363 | { |
f646e227 | 2364 | sigset_t retarget; |
0edceb7b ON |
2365 | struct task_struct *t; |
2366 | ||
f646e227 ON |
2367 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2368 | if (sigisemptyset(&retarget)) | |
2369 | return; | |
2370 | ||
0edceb7b ON |
2371 | t = tsk; |
2372 | while_each_thread(tsk, t) { | |
fec9993d ON |
2373 | if (t->flags & PF_EXITING) |
2374 | continue; | |
2375 | ||
2376 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2377 | continue; | |
2378 | /* Remove the signals this thread can handle. */ | |
2379 | sigandsets(&retarget, &retarget, &t->blocked); | |
2380 | ||
2381 | if (!signal_pending(t)) | |
2382 | signal_wake_up(t, 0); | |
2383 | ||
2384 | if (sigisemptyset(&retarget)) | |
2385 | break; | |
0edceb7b ON |
2386 | } |
2387 | } | |
2388 | ||
d12619b5 ON |
2389 | void exit_signals(struct task_struct *tsk) |
2390 | { | |
2391 | int group_stop = 0; | |
f646e227 | 2392 | sigset_t unblocked; |
d12619b5 | 2393 | |
77e4ef99 TH |
2394 | /* |
2395 | * @tsk is about to have PF_EXITING set - lock out users which | |
2396 | * expect stable threadgroup. | |
2397 | */ | |
2398 | threadgroup_change_begin(tsk); | |
2399 | ||
5dee1707 ON |
2400 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2401 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2402 | threadgroup_change_end(tsk); |
5dee1707 | 2403 | return; |
d12619b5 ON |
2404 | } |
2405 | ||
5dee1707 | 2406 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2407 | /* |
2408 | * From now this task is not visible for group-wide signals, | |
2409 | * see wants_signal(), do_signal_stop(). | |
2410 | */ | |
2411 | tsk->flags |= PF_EXITING; | |
77e4ef99 TH |
2412 | |
2413 | threadgroup_change_end(tsk); | |
2414 | ||
5dee1707 ON |
2415 | if (!signal_pending(tsk)) |
2416 | goto out; | |
2417 | ||
f646e227 ON |
2418 | unblocked = tsk->blocked; |
2419 | signotset(&unblocked); | |
2420 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2421 | |
a8f072c1 | 2422 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2423 | task_participate_group_stop(tsk)) |
edf2ed15 | 2424 | group_stop = CLD_STOPPED; |
5dee1707 | 2425 | out: |
d12619b5 ON |
2426 | spin_unlock_irq(&tsk->sighand->siglock); |
2427 | ||
62bcf9d9 TH |
2428 | /* |
2429 | * If group stop has completed, deliver the notification. This | |
2430 | * should always go to the real parent of the group leader. | |
2431 | */ | |
ae6d2ed7 | 2432 | if (unlikely(group_stop)) { |
d12619b5 | 2433 | read_lock(&tasklist_lock); |
62bcf9d9 | 2434 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2435 | read_unlock(&tasklist_lock); |
2436 | } | |
2437 | } | |
2438 | ||
1da177e4 LT |
2439 | EXPORT_SYMBOL(recalc_sigpending); |
2440 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2441 | EXPORT_SYMBOL(flush_signals); | |
2442 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2443 | EXPORT_SYMBOL(send_sig); |
2444 | EXPORT_SYMBOL(send_sig_info); | |
2445 | EXPORT_SYMBOL(sigprocmask); | |
1da177e4 LT |
2446 | |
2447 | /* | |
2448 | * System call entry points. | |
2449 | */ | |
2450 | ||
41c57892 RD |
2451 | /** |
2452 | * sys_restart_syscall - restart a system call | |
2453 | */ | |
754fe8d2 | 2454 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 | 2455 | { |
f56141e3 | 2456 | struct restart_block *restart = ¤t->restart_block; |
1da177e4 LT |
2457 | return restart->fn(restart); |
2458 | } | |
2459 | ||
2460 | long do_no_restart_syscall(struct restart_block *param) | |
2461 | { | |
2462 | return -EINTR; | |
2463 | } | |
2464 | ||
b182801a ON |
2465 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2466 | { | |
2467 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2468 | sigset_t newblocked; | |
2469 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2470 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2471 | retarget_shared_pending(tsk, &newblocked); |
2472 | } | |
2473 | tsk->blocked = *newset; | |
2474 | recalc_sigpending(); | |
2475 | } | |
2476 | ||
e6fa16ab ON |
2477 | /** |
2478 | * set_current_blocked - change current->blocked mask | |
2479 | * @newset: new mask | |
2480 | * | |
2481 | * It is wrong to change ->blocked directly, this helper should be used | |
2482 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2483 | */ |
77097ae5 AV |
2484 | void set_current_blocked(sigset_t *newset) |
2485 | { | |
77097ae5 | 2486 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2487 | __set_current_blocked(newset); |
77097ae5 AV |
2488 | } |
2489 | ||
2490 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2491 | { |
2492 | struct task_struct *tsk = current; | |
2493 | ||
c7be96af WL |
2494 | /* |
2495 | * In case the signal mask hasn't changed, there is nothing we need | |
2496 | * to do. The current->blocked shouldn't be modified by other task. | |
2497 | */ | |
2498 | if (sigequalsets(&tsk->blocked, newset)) | |
2499 | return; | |
2500 | ||
e6fa16ab | 2501 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2502 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2503 | spin_unlock_irq(&tsk->sighand->siglock); |
2504 | } | |
1da177e4 LT |
2505 | |
2506 | /* | |
2507 | * This is also useful for kernel threads that want to temporarily | |
2508 | * (or permanently) block certain signals. | |
2509 | * | |
2510 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2511 | * interface happily blocks "unblockable" signals like SIGKILL | |
2512 | * and friends. | |
2513 | */ | |
2514 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2515 | { | |
73ef4aeb ON |
2516 | struct task_struct *tsk = current; |
2517 | sigset_t newset; | |
1da177e4 | 2518 | |
73ef4aeb | 2519 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2520 | if (oldset) |
73ef4aeb | 2521 | *oldset = tsk->blocked; |
a26fd335 | 2522 | |
1da177e4 LT |
2523 | switch (how) { |
2524 | case SIG_BLOCK: | |
73ef4aeb | 2525 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2526 | break; |
2527 | case SIG_UNBLOCK: | |
702a5073 | 2528 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2529 | break; |
2530 | case SIG_SETMASK: | |
73ef4aeb | 2531 | newset = *set; |
1da177e4 LT |
2532 | break; |
2533 | default: | |
73ef4aeb | 2534 | return -EINVAL; |
1da177e4 | 2535 | } |
a26fd335 | 2536 | |
77097ae5 | 2537 | __set_current_blocked(&newset); |
73ef4aeb | 2538 | return 0; |
1da177e4 LT |
2539 | } |
2540 | ||
41c57892 RD |
2541 | /** |
2542 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2543 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2544 | * @nset: stores pending signals |
41c57892 RD |
2545 | * @oset: previous value of signal mask if non-null |
2546 | * @sigsetsize: size of sigset_t type | |
2547 | */ | |
bb7efee2 | 2548 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2549 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2550 | { |
1da177e4 | 2551 | sigset_t old_set, new_set; |
bb7efee2 | 2552 | int error; |
1da177e4 LT |
2553 | |
2554 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2555 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2556 | return -EINVAL; |
1da177e4 | 2557 | |
bb7efee2 ON |
2558 | old_set = current->blocked; |
2559 | ||
2560 | if (nset) { | |
2561 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2562 | return -EFAULT; | |
1da177e4 LT |
2563 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2564 | ||
bb7efee2 | 2565 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2566 | if (error) |
bb7efee2 ON |
2567 | return error; |
2568 | } | |
1da177e4 | 2569 | |
bb7efee2 ON |
2570 | if (oset) { |
2571 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2572 | return -EFAULT; | |
1da177e4 | 2573 | } |
bb7efee2 ON |
2574 | |
2575 | return 0; | |
1da177e4 LT |
2576 | } |
2577 | ||
322a56cb | 2578 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2579 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2580 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2581 | { |
322a56cb AV |
2582 | #ifdef __BIG_ENDIAN |
2583 | sigset_t old_set = current->blocked; | |
2584 | ||
2585 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2586 | if (sigsetsize != sizeof(sigset_t)) | |
2587 | return -EINVAL; | |
2588 | ||
2589 | if (nset) { | |
2590 | compat_sigset_t new32; | |
2591 | sigset_t new_set; | |
2592 | int error; | |
2593 | if (copy_from_user(&new32, nset, sizeof(compat_sigset_t))) | |
2594 | return -EFAULT; | |
2595 | ||
2596 | sigset_from_compat(&new_set, &new32); | |
2597 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2598 | ||
2599 | error = sigprocmask(how, &new_set, NULL); | |
2600 | if (error) | |
2601 | return error; | |
2602 | } | |
2603 | if (oset) { | |
2604 | compat_sigset_t old32; | |
2605 | sigset_to_compat(&old32, &old_set); | |
db61ec29 | 2606 | if (copy_to_user(oset, &old32, sizeof(compat_sigset_t))) |
322a56cb AV |
2607 | return -EFAULT; |
2608 | } | |
2609 | return 0; | |
2610 | #else | |
2611 | return sys_rt_sigprocmask(how, (sigset_t __user *)nset, | |
2612 | (sigset_t __user *)oset, sigsetsize); | |
2613 | #endif | |
2614 | } | |
2615 | #endif | |
1da177e4 | 2616 | |
fe9c1db2 | 2617 | static int do_sigpending(void *set, unsigned long sigsetsize) |
1da177e4 | 2618 | { |
1da177e4 | 2619 | if (sigsetsize > sizeof(sigset_t)) |
fe9c1db2 | 2620 | return -EINVAL; |
1da177e4 LT |
2621 | |
2622 | spin_lock_irq(¤t->sighand->siglock); | |
fe9c1db2 | 2623 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
2624 | ¤t->signal->shared_pending.signal); |
2625 | spin_unlock_irq(¤t->sighand->siglock); | |
2626 | ||
2627 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 AV |
2628 | sigandsets(set, ¤t->blocked, set); |
2629 | return 0; | |
5aba085e | 2630 | } |
1da177e4 | 2631 | |
41c57892 RD |
2632 | /** |
2633 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2634 | * while blocked | |
20f22ab4 | 2635 | * @uset: stores pending signals |
41c57892 RD |
2636 | * @sigsetsize: size of sigset_t type or larger |
2637 | */ | |
fe9c1db2 | 2638 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 2639 | { |
fe9c1db2 AV |
2640 | sigset_t set; |
2641 | int err = do_sigpending(&set, sigsetsize); | |
2642 | if (!err && copy_to_user(uset, &set, sigsetsize)) | |
2643 | err = -EFAULT; | |
2644 | return err; | |
2645 | } | |
2646 | ||
2647 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
2648 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
2649 | compat_size_t, sigsetsize) | |
1da177e4 | 2650 | { |
fe9c1db2 AV |
2651 | #ifdef __BIG_ENDIAN |
2652 | sigset_t set; | |
2653 | int err = do_sigpending(&set, sigsetsize); | |
2654 | if (!err) { | |
2655 | compat_sigset_t set32; | |
2656 | sigset_to_compat(&set32, &set); | |
2657 | /* we can get here only if sigsetsize <= sizeof(set) */ | |
2658 | if (copy_to_user(uset, &set32, sigsetsize)) | |
2659 | err = -EFAULT; | |
2660 | } | |
2661 | return err; | |
2662 | #else | |
2663 | return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize); | |
2664 | #endif | |
1da177e4 | 2665 | } |
fe9c1db2 | 2666 | #endif |
1da177e4 LT |
2667 | |
2668 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2669 | ||
ce395960 | 2670 | int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) |
1da177e4 LT |
2671 | { |
2672 | int err; | |
2673 | ||
2674 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2675 | return -EFAULT; | |
2676 | if (from->si_code < 0) | |
2677 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2678 | ? -EFAULT : 0; | |
2679 | /* | |
2680 | * If you change siginfo_t structure, please be sure | |
2681 | * this code is fixed accordingly. | |
fba2afaa DL |
2682 | * Please remember to update the signalfd_copyinfo() function |
2683 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2684 | * It should never copy any pad contained in the structure |
2685 | * to avoid security leaks, but must copy the generic | |
2686 | * 3 ints plus the relevant union member. | |
2687 | */ | |
2688 | err = __put_user(from->si_signo, &to->si_signo); | |
2689 | err |= __put_user(from->si_errno, &to->si_errno); | |
2690 | err |= __put_user((short)from->si_code, &to->si_code); | |
2691 | switch (from->si_code & __SI_MASK) { | |
2692 | case __SI_KILL: | |
2693 | err |= __put_user(from->si_pid, &to->si_pid); | |
2694 | err |= __put_user(from->si_uid, &to->si_uid); | |
2695 | break; | |
2696 | case __SI_TIMER: | |
2697 | err |= __put_user(from->si_tid, &to->si_tid); | |
2698 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2699 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2700 | break; | |
2701 | case __SI_POLL: | |
2702 | err |= __put_user(from->si_band, &to->si_band); | |
2703 | err |= __put_user(from->si_fd, &to->si_fd); | |
2704 | break; | |
2705 | case __SI_FAULT: | |
2706 | err |= __put_user(from->si_addr, &to->si_addr); | |
2707 | #ifdef __ARCH_SI_TRAPNO | |
2708 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2709 | #endif |
2710 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2711 | /* |
a337fdac | 2712 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2713 | * so check explicitly for the right codes here. |
a337fdac | 2714 | */ |
26135022 AA |
2715 | if (from->si_signo == SIGBUS && |
2716 | (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) | |
a337fdac | 2717 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); |
ee1b58d3 QR |
2718 | #endif |
2719 | #ifdef SEGV_BNDERR | |
26135022 AA |
2720 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) { |
2721 | err |= __put_user(from->si_lower, &to->si_lower); | |
2722 | err |= __put_user(from->si_upper, &to->si_upper); | |
2723 | } | |
cd0ea35f DH |
2724 | #endif |
2725 | #ifdef SEGV_PKUERR | |
2726 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR) | |
2727 | err |= __put_user(from->si_pkey, &to->si_pkey); | |
1da177e4 LT |
2728 | #endif |
2729 | break; | |
2730 | case __SI_CHLD: | |
2731 | err |= __put_user(from->si_pid, &to->si_pid); | |
2732 | err |= __put_user(from->si_uid, &to->si_uid); | |
2733 | err |= __put_user(from->si_status, &to->si_status); | |
2734 | err |= __put_user(from->si_utime, &to->si_utime); | |
2735 | err |= __put_user(from->si_stime, &to->si_stime); | |
2736 | break; | |
2737 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2738 | case __SI_MESGQ: /* But this is */ | |
2739 | err |= __put_user(from->si_pid, &to->si_pid); | |
2740 | err |= __put_user(from->si_uid, &to->si_uid); | |
2741 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2742 | break; | |
a0727e8c WD |
2743 | #ifdef __ARCH_SIGSYS |
2744 | case __SI_SYS: | |
2745 | err |= __put_user(from->si_call_addr, &to->si_call_addr); | |
2746 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2747 | err |= __put_user(from->si_arch, &to->si_arch); | |
2748 | break; | |
2749 | #endif | |
1da177e4 LT |
2750 | default: /* this is just in case for now ... */ |
2751 | err |= __put_user(from->si_pid, &to->si_pid); | |
2752 | err |= __put_user(from->si_uid, &to->si_uid); | |
2753 | break; | |
2754 | } | |
2755 | return err; | |
2756 | } | |
2757 | ||
2758 | #endif | |
2759 | ||
943df148 ON |
2760 | /** |
2761 | * do_sigtimedwait - wait for queued signals specified in @which | |
2762 | * @which: queued signals to wait for | |
2763 | * @info: if non-null, the signal's siginfo is returned here | |
2764 | * @ts: upper bound on process time suspension | |
2765 | */ | |
2766 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info, | |
2b1ecc3d | 2767 | const struct timespec *ts) |
943df148 | 2768 | { |
2456e855 | 2769 | ktime_t *to = NULL, timeout = KTIME_MAX; |
943df148 | 2770 | struct task_struct *tsk = current; |
943df148 | 2771 | sigset_t mask = *which; |
2b1ecc3d | 2772 | int sig, ret = 0; |
943df148 ON |
2773 | |
2774 | if (ts) { | |
2775 | if (!timespec_valid(ts)) | |
2776 | return -EINVAL; | |
2b1ecc3d TG |
2777 | timeout = timespec_to_ktime(*ts); |
2778 | to = &timeout; | |
943df148 ON |
2779 | } |
2780 | ||
2781 | /* | |
2782 | * Invert the set of allowed signals to get those we want to block. | |
2783 | */ | |
2784 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2785 | signotset(&mask); | |
2786 | ||
2787 | spin_lock_irq(&tsk->sighand->siglock); | |
2788 | sig = dequeue_signal(tsk, &mask, info); | |
2456e855 | 2789 | if (!sig && timeout) { |
943df148 ON |
2790 | /* |
2791 | * None ready, temporarily unblock those we're interested | |
2792 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2793 | * they arrive. Unblocking is always fine, we can avoid |
2794 | * set_current_blocked(). | |
943df148 ON |
2795 | */ |
2796 | tsk->real_blocked = tsk->blocked; | |
2797 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2798 | recalc_sigpending(); | |
2799 | spin_unlock_irq(&tsk->sighand->siglock); | |
2800 | ||
2b1ecc3d TG |
2801 | __set_current_state(TASK_INTERRUPTIBLE); |
2802 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, | |
2803 | HRTIMER_MODE_REL); | |
943df148 | 2804 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2805 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 2806 | sigemptyset(&tsk->real_blocked); |
b182801a | 2807 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2808 | } |
2809 | spin_unlock_irq(&tsk->sighand->siglock); | |
2810 | ||
2811 | if (sig) | |
2812 | return sig; | |
2b1ecc3d | 2813 | return ret ? -EINTR : -EAGAIN; |
943df148 ON |
2814 | } |
2815 | ||
41c57892 RD |
2816 | /** |
2817 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2818 | * in @uthese | |
2819 | * @uthese: queued signals to wait for | |
2820 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2821 | * @uts: upper bound on process time suspension | |
2822 | * @sigsetsize: size of sigset_t type | |
2823 | */ | |
17da2bd9 HC |
2824 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2825 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2826 | size_t, sigsetsize) | |
1da177e4 | 2827 | { |
1da177e4 LT |
2828 | sigset_t these; |
2829 | struct timespec ts; | |
2830 | siginfo_t info; | |
943df148 | 2831 | int ret; |
1da177e4 LT |
2832 | |
2833 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2834 | if (sigsetsize != sizeof(sigset_t)) | |
2835 | return -EINVAL; | |
2836 | ||
2837 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2838 | return -EFAULT; | |
5aba085e | 2839 | |
1da177e4 LT |
2840 | if (uts) { |
2841 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2842 | return -EFAULT; | |
1da177e4 LT |
2843 | } |
2844 | ||
943df148 | 2845 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2846 | |
943df148 ON |
2847 | if (ret > 0 && uinfo) { |
2848 | if (copy_siginfo_to_user(uinfo, &info)) | |
2849 | ret = -EFAULT; | |
1da177e4 LT |
2850 | } |
2851 | ||
2852 | return ret; | |
2853 | } | |
2854 | ||
41c57892 RD |
2855 | /** |
2856 | * sys_kill - send a signal to a process | |
2857 | * @pid: the PID of the process | |
2858 | * @sig: signal to be sent | |
2859 | */ | |
17da2bd9 | 2860 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2861 | { |
2862 | struct siginfo info; | |
2863 | ||
2864 | info.si_signo = sig; | |
2865 | info.si_errno = 0; | |
2866 | info.si_code = SI_USER; | |
b488893a | 2867 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2868 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2869 | |
2870 | return kill_something_info(sig, &info, pid); | |
2871 | } | |
2872 | ||
30b4ae8a TG |
2873 | static int |
2874 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2875 | { |
1da177e4 | 2876 | struct task_struct *p; |
30b4ae8a | 2877 | int error = -ESRCH; |
1da177e4 | 2878 | |
3547ff3a | 2879 | rcu_read_lock(); |
228ebcbe | 2880 | p = find_task_by_vpid(pid); |
b488893a | 2881 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2882 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2883 | /* |
2884 | * The null signal is a permissions and process existence | |
2885 | * probe. No signal is actually delivered. | |
2886 | */ | |
4a30debf ON |
2887 | if (!error && sig) { |
2888 | error = do_send_sig_info(sig, info, p, false); | |
2889 | /* | |
2890 | * If lock_task_sighand() failed we pretend the task | |
2891 | * dies after receiving the signal. The window is tiny, | |
2892 | * and the signal is private anyway. | |
2893 | */ | |
2894 | if (unlikely(error == -ESRCH)) | |
2895 | error = 0; | |
1da177e4 LT |
2896 | } |
2897 | } | |
3547ff3a | 2898 | rcu_read_unlock(); |
6dd69f10 | 2899 | |
1da177e4 LT |
2900 | return error; |
2901 | } | |
2902 | ||
30b4ae8a TG |
2903 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2904 | { | |
b9e146d8 | 2905 | struct siginfo info = {}; |
30b4ae8a TG |
2906 | |
2907 | info.si_signo = sig; | |
2908 | info.si_errno = 0; | |
2909 | info.si_code = SI_TKILL; | |
2910 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 2911 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
2912 | |
2913 | return do_send_specific(tgid, pid, sig, &info); | |
2914 | } | |
2915 | ||
6dd69f10 VL |
2916 | /** |
2917 | * sys_tgkill - send signal to one specific thread | |
2918 | * @tgid: the thread group ID of the thread | |
2919 | * @pid: the PID of the thread | |
2920 | * @sig: signal to be sent | |
2921 | * | |
72fd4a35 | 2922 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2923 | * exists but it's not belonging to the target process anymore. This |
2924 | * method solves the problem of threads exiting and PIDs getting reused. | |
2925 | */ | |
a5f8fa9e | 2926 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2927 | { |
2928 | /* This is only valid for single tasks */ | |
2929 | if (pid <= 0 || tgid <= 0) | |
2930 | return -EINVAL; | |
2931 | ||
2932 | return do_tkill(tgid, pid, sig); | |
2933 | } | |
2934 | ||
41c57892 RD |
2935 | /** |
2936 | * sys_tkill - send signal to one specific task | |
2937 | * @pid: the PID of the task | |
2938 | * @sig: signal to be sent | |
2939 | * | |
1da177e4 LT |
2940 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2941 | */ | |
a5f8fa9e | 2942 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2943 | { |
1da177e4 LT |
2944 | /* This is only valid for single tasks */ |
2945 | if (pid <= 0) | |
2946 | return -EINVAL; | |
2947 | ||
6dd69f10 | 2948 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2949 | } |
2950 | ||
75907d4d AV |
2951 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) |
2952 | { | |
2953 | /* Not even root can pretend to send signals from the kernel. | |
2954 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
2955 | */ | |
66dd34ad | 2956 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
69828dce | 2957 | (task_pid_vnr(current) != pid)) |
75907d4d | 2958 | return -EPERM; |
69828dce | 2959 | |
75907d4d AV |
2960 | info->si_signo = sig; |
2961 | ||
2962 | /* POSIX.1b doesn't mention process groups. */ | |
2963 | return kill_proc_info(sig, info, pid); | |
2964 | } | |
2965 | ||
41c57892 RD |
2966 | /** |
2967 | * sys_rt_sigqueueinfo - send signal information to a signal | |
2968 | * @pid: the PID of the thread | |
2969 | * @sig: signal to be sent | |
2970 | * @uinfo: signal info to be sent | |
2971 | */ | |
a5f8fa9e HC |
2972 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2973 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2974 | { |
2975 | siginfo_t info; | |
1da177e4 LT |
2976 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) |
2977 | return -EFAULT; | |
75907d4d AV |
2978 | return do_rt_sigqueueinfo(pid, sig, &info); |
2979 | } | |
1da177e4 | 2980 | |
75907d4d | 2981 | #ifdef CONFIG_COMPAT |
75907d4d AV |
2982 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
2983 | compat_pid_t, pid, | |
2984 | int, sig, | |
2985 | struct compat_siginfo __user *, uinfo) | |
2986 | { | |
3c00cb5e | 2987 | siginfo_t info = {}; |
75907d4d AV |
2988 | int ret = copy_siginfo_from_user32(&info, uinfo); |
2989 | if (unlikely(ret)) | |
2990 | return ret; | |
2991 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 2992 | } |
75907d4d | 2993 | #endif |
1da177e4 | 2994 | |
9aae8fc0 | 2995 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
62ab4505 TG |
2996 | { |
2997 | /* This is only valid for single tasks */ | |
2998 | if (pid <= 0 || tgid <= 0) | |
2999 | return -EINVAL; | |
3000 | ||
3001 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3002 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3003 | */ | |
69828dce VD |
3004 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3005 | (task_pid_vnr(current) != pid)) | |
62ab4505 | 3006 | return -EPERM; |
69828dce | 3007 | |
62ab4505 TG |
3008 | info->si_signo = sig; |
3009 | ||
3010 | return do_send_specific(tgid, pid, sig, info); | |
3011 | } | |
3012 | ||
3013 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3014 | siginfo_t __user *, uinfo) | |
3015 | { | |
3016 | siginfo_t info; | |
3017 | ||
3018 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3019 | return -EFAULT; | |
3020 | ||
3021 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3022 | } | |
3023 | ||
9aae8fc0 AV |
3024 | #ifdef CONFIG_COMPAT |
3025 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3026 | compat_pid_t, tgid, | |
3027 | compat_pid_t, pid, | |
3028 | int, sig, | |
3029 | struct compat_siginfo __user *, uinfo) | |
3030 | { | |
3c00cb5e | 3031 | siginfo_t info = {}; |
9aae8fc0 AV |
3032 | |
3033 | if (copy_siginfo_from_user32(&info, uinfo)) | |
3034 | return -EFAULT; | |
3035 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3036 | } | |
3037 | #endif | |
3038 | ||
0341729b | 3039 | /* |
b4e74264 | 3040 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
0341729b | 3041 | */ |
b4e74264 | 3042 | void kernel_sigaction(int sig, __sighandler_t action) |
0341729b | 3043 | { |
ec5955b8 | 3044 | spin_lock_irq(¤t->sighand->siglock); |
b4e74264 ON |
3045 | current->sighand->action[sig - 1].sa.sa_handler = action; |
3046 | if (action == SIG_IGN) { | |
3047 | sigset_t mask; | |
0341729b | 3048 | |
b4e74264 ON |
3049 | sigemptyset(&mask); |
3050 | sigaddset(&mask, sig); | |
580d34e4 | 3051 | |
b4e74264 ON |
3052 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
3053 | flush_sigqueue_mask(&mask, ¤t->pending); | |
3054 | recalc_sigpending(); | |
3055 | } | |
0341729b ON |
3056 | spin_unlock_irq(¤t->sighand->siglock); |
3057 | } | |
b4e74264 | 3058 | EXPORT_SYMBOL(kernel_sigaction); |
0341729b | 3059 | |
68463510 DS |
3060 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
3061 | struct k_sigaction *oact) | |
3062 | { | |
3063 | } | |
3064 | ||
88531f72 | 3065 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3066 | { |
afe2b038 | 3067 | struct task_struct *p = current, *t; |
1da177e4 | 3068 | struct k_sigaction *k; |
71fabd5e | 3069 | sigset_t mask; |
1da177e4 | 3070 | |
7ed20e1a | 3071 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3072 | return -EINVAL; |
3073 | ||
afe2b038 | 3074 | k = &p->sighand->action[sig-1]; |
1da177e4 | 3075 | |
afe2b038 | 3076 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
3077 | if (oact) |
3078 | *oact = *k; | |
3079 | ||
68463510 DS |
3080 | sigaction_compat_abi(act, oact); |
3081 | ||
1da177e4 | 3082 | if (act) { |
9ac95f2f ON |
3083 | sigdelsetmask(&act->sa.sa_mask, |
3084 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3085 | *k = *act; |
1da177e4 LT |
3086 | /* |
3087 | * POSIX 3.3.1.3: | |
3088 | * "Setting a signal action to SIG_IGN for a signal that is | |
3089 | * pending shall cause the pending signal to be discarded, | |
3090 | * whether or not it is blocked." | |
3091 | * | |
3092 | * "Setting a signal action to SIG_DFL for a signal that is | |
3093 | * pending and whose default action is to ignore the signal | |
3094 | * (for example, SIGCHLD), shall cause the pending signal to | |
3095 | * be discarded, whether or not it is blocked" | |
3096 | */ | |
afe2b038 | 3097 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
71fabd5e GA |
3098 | sigemptyset(&mask); |
3099 | sigaddset(&mask, sig); | |
afe2b038 ON |
3100 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
3101 | for_each_thread(p, t) | |
c09c1441 | 3102 | flush_sigqueue_mask(&mask, &t->pending); |
1da177e4 | 3103 | } |
1da177e4 LT |
3104 | } |
3105 | ||
afe2b038 | 3106 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
3107 | return 0; |
3108 | } | |
3109 | ||
c09c1441 | 3110 | static int |
1da177e4 LT |
3111 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) |
3112 | { | |
3113 | stack_t oss; | |
3114 | int error; | |
3115 | ||
0083fc2c LT |
3116 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
3117 | oss.ss_size = current->sas_ss_size; | |
0318bc8a AL |
3118 | oss.ss_flags = sas_ss_flags(sp) | |
3119 | (current->sas_ss_flags & SS_FLAG_BITS); | |
1da177e4 LT |
3120 | |
3121 | if (uss) { | |
3122 | void __user *ss_sp; | |
3123 | size_t ss_size; | |
407bc16a SS |
3124 | unsigned ss_flags; |
3125 | int ss_mode; | |
1da177e4 LT |
3126 | |
3127 | error = -EFAULT; | |
0dd8486b LT |
3128 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
3129 | goto out; | |
3130 | error = __get_user(ss_sp, &uss->ss_sp) | | |
3131 | __get_user(ss_flags, &uss->ss_flags) | | |
3132 | __get_user(ss_size, &uss->ss_size); | |
3133 | if (error) | |
1da177e4 LT |
3134 | goto out; |
3135 | ||
3136 | error = -EPERM; | |
3137 | if (on_sig_stack(sp)) | |
3138 | goto out; | |
3139 | ||
407bc16a | 3140 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
1da177e4 | 3141 | error = -EINVAL; |
407bc16a SS |
3142 | if (ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
3143 | ss_mode != 0) | |
1da177e4 LT |
3144 | goto out; |
3145 | ||
407bc16a | 3146 | if (ss_mode == SS_DISABLE) { |
1da177e4 LT |
3147 | ss_size = 0; |
3148 | ss_sp = NULL; | |
3149 | } else { | |
3150 | error = -ENOMEM; | |
3151 | if (ss_size < MINSIGSTKSZ) | |
3152 | goto out; | |
3153 | } | |
3154 | ||
3155 | current->sas_ss_sp = (unsigned long) ss_sp; | |
3156 | current->sas_ss_size = ss_size; | |
2a742138 | 3157 | current->sas_ss_flags = ss_flags; |
1da177e4 LT |
3158 | } |
3159 | ||
0083fc2c | 3160 | error = 0; |
1da177e4 LT |
3161 | if (uoss) { |
3162 | error = -EFAULT; | |
0083fc2c | 3163 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 3164 | goto out; |
0083fc2c LT |
3165 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
3166 | __put_user(oss.ss_size, &uoss->ss_size) | | |
3167 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
3168 | } |
3169 | ||
1da177e4 LT |
3170 | out: |
3171 | return error; | |
3172 | } | |
6bf9adfc AV |
3173 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3174 | { | |
3175 | return do_sigaltstack(uss, uoss, current_user_stack_pointer()); | |
3176 | } | |
1da177e4 | 3177 | |
5c49574f AV |
3178 | int restore_altstack(const stack_t __user *uss) |
3179 | { | |
3180 | int err = do_sigaltstack(uss, NULL, current_user_stack_pointer()); | |
3181 | /* squash all but EFAULT for now */ | |
3182 | return err == -EFAULT ? err : 0; | |
3183 | } | |
3184 | ||
c40702c4 AV |
3185 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3186 | { | |
3187 | struct task_struct *t = current; | |
2a742138 SS |
3188 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
3189 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3190 | __put_user(t->sas_ss_size, &uss->ss_size); |
2a742138 SS |
3191 | if (err) |
3192 | return err; | |
3193 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3194 | sas_ss_reset(t); | |
3195 | return 0; | |
c40702c4 AV |
3196 | } |
3197 | ||
90268439 | 3198 | #ifdef CONFIG_COMPAT |
90228fc1 AV |
3199 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
3200 | const compat_stack_t __user *, uss_ptr, | |
3201 | compat_stack_t __user *, uoss_ptr) | |
90268439 AV |
3202 | { |
3203 | stack_t uss, uoss; | |
3204 | int ret; | |
3205 | mm_segment_t seg; | |
3206 | ||
3207 | if (uss_ptr) { | |
3208 | compat_stack_t uss32; | |
3209 | ||
3210 | memset(&uss, 0, sizeof(stack_t)); | |
3211 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) | |
3212 | return -EFAULT; | |
3213 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
3214 | uss.ss_flags = uss32.ss_flags; | |
3215 | uss.ss_size = uss32.ss_size; | |
3216 | } | |
3217 | seg = get_fs(); | |
3218 | set_fs(KERNEL_DS); | |
3219 | ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), | |
3220 | (stack_t __force __user *) &uoss, | |
3221 | compat_user_stack_pointer()); | |
3222 | set_fs(seg); | |
3223 | if (ret >= 0 && uoss_ptr) { | |
3224 | if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) || | |
3225 | __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) || | |
3226 | __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) || | |
3227 | __put_user(uoss.ss_size, &uoss_ptr->ss_size)) | |
3228 | ret = -EFAULT; | |
3229 | } | |
3230 | return ret; | |
3231 | } | |
3232 | ||
3233 | int compat_restore_altstack(const compat_stack_t __user *uss) | |
3234 | { | |
3235 | int err = compat_sys_sigaltstack(uss, NULL); | |
3236 | /* squash all but -EFAULT for now */ | |
3237 | return err == -EFAULT ? err : 0; | |
3238 | } | |
c40702c4 AV |
3239 | |
3240 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
3241 | { | |
3242 | struct task_struct *t = current; | |
3243 | return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) | | |
3244 | __put_user(sas_ss_flags(sp), &uss->ss_flags) | | |
3245 | __put_user(t->sas_ss_size, &uss->ss_size); | |
3246 | } | |
90268439 | 3247 | #endif |
1da177e4 LT |
3248 | |
3249 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3250 | ||
41c57892 RD |
3251 | /** |
3252 | * sys_sigpending - examine pending signals | |
3253 | * @set: where mask of pending signal is returned | |
3254 | */ | |
b290ebe2 | 3255 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 | 3256 | { |
fe9c1db2 | 3257 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); |
1da177e4 LT |
3258 | } |
3259 | ||
3260 | #endif | |
3261 | ||
3262 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3263 | /** |
3264 | * sys_sigprocmask - examine and change blocked signals | |
3265 | * @how: whether to add, remove, or set signals | |
b013c399 | 3266 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3267 | * @oset: previous value of signal mask if non-null |
3268 | * | |
5aba085e RD |
3269 | * Some platforms have their own version with special arguments; |
3270 | * others support only sys_rt_sigprocmask. | |
3271 | */ | |
1da177e4 | 3272 | |
b013c399 | 3273 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3274 | old_sigset_t __user *, oset) |
1da177e4 | 3275 | { |
1da177e4 | 3276 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3277 | sigset_t new_blocked; |
1da177e4 | 3278 | |
b013c399 | 3279 | old_set = current->blocked.sig[0]; |
1da177e4 | 3280 | |
b013c399 ON |
3281 | if (nset) { |
3282 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3283 | return -EFAULT; | |
1da177e4 | 3284 | |
2e4f7c77 | 3285 | new_blocked = current->blocked; |
1da177e4 | 3286 | |
1da177e4 | 3287 | switch (how) { |
1da177e4 | 3288 | case SIG_BLOCK: |
2e4f7c77 | 3289 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3290 | break; |
3291 | case SIG_UNBLOCK: | |
2e4f7c77 | 3292 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3293 | break; |
3294 | case SIG_SETMASK: | |
2e4f7c77 | 3295 | new_blocked.sig[0] = new_set; |
1da177e4 | 3296 | break; |
2e4f7c77 ON |
3297 | default: |
3298 | return -EINVAL; | |
1da177e4 LT |
3299 | } |
3300 | ||
0c4a8423 | 3301 | set_current_blocked(&new_blocked); |
b013c399 ON |
3302 | } |
3303 | ||
3304 | if (oset) { | |
1da177e4 | 3305 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3306 | return -EFAULT; |
1da177e4 | 3307 | } |
b013c399 ON |
3308 | |
3309 | return 0; | |
1da177e4 LT |
3310 | } |
3311 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3312 | ||
eaca6eae | 3313 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
3314 | /** |
3315 | * sys_rt_sigaction - alter an action taken by a process | |
3316 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3317 | * @act: new sigaction |
3318 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3319 | * @sigsetsize: size of sigset_t type |
3320 | */ | |
d4e82042 HC |
3321 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3322 | const struct sigaction __user *, act, | |
3323 | struct sigaction __user *, oact, | |
3324 | size_t, sigsetsize) | |
1da177e4 LT |
3325 | { |
3326 | struct k_sigaction new_sa, old_sa; | |
3327 | int ret = -EINVAL; | |
3328 | ||
3329 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3330 | if (sigsetsize != sizeof(sigset_t)) | |
3331 | goto out; | |
3332 | ||
3333 | if (act) { | |
3334 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3335 | return -EFAULT; | |
3336 | } | |
3337 | ||
3338 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3339 | ||
3340 | if (!ret && oact) { | |
3341 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3342 | return -EFAULT; | |
3343 | } | |
3344 | out: | |
3345 | return ret; | |
3346 | } | |
08d32fe5 | 3347 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
3348 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3349 | const struct compat_sigaction __user *, act, | |
3350 | struct compat_sigaction __user *, oact, | |
3351 | compat_size_t, sigsetsize) | |
3352 | { | |
3353 | struct k_sigaction new_ka, old_ka; | |
3354 | compat_sigset_t mask; | |
3355 | #ifdef __ARCH_HAS_SA_RESTORER | |
3356 | compat_uptr_t restorer; | |
3357 | #endif | |
3358 | int ret; | |
3359 | ||
3360 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3361 | if (sigsetsize != sizeof(compat_sigset_t)) | |
3362 | return -EINVAL; | |
3363 | ||
3364 | if (act) { | |
3365 | compat_uptr_t handler; | |
3366 | ret = get_user(handler, &act->sa_handler); | |
3367 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3368 | #ifdef __ARCH_HAS_SA_RESTORER | |
3369 | ret |= get_user(restorer, &act->sa_restorer); | |
3370 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3371 | #endif | |
3372 | ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask)); | |
3ddc5b46 | 3373 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
3374 | if (ret) |
3375 | return -EFAULT; | |
3376 | sigset_from_compat(&new_ka.sa.sa_mask, &mask); | |
3377 | } | |
3378 | ||
3379 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3380 | if (!ret && oact) { | |
3381 | sigset_to_compat(&mask, &old_ka.sa.sa_mask); | |
3382 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3383 | &oact->sa_handler); | |
3384 | ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask)); | |
3ddc5b46 | 3385 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
3386 | #ifdef __ARCH_HAS_SA_RESTORER |
3387 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3388 | &oact->sa_restorer); | |
3389 | #endif | |
3390 | } | |
3391 | return ret; | |
3392 | } | |
3393 | #endif | |
eaca6eae | 3394 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 3395 | |
495dfbf7 AV |
3396 | #ifdef CONFIG_OLD_SIGACTION |
3397 | SYSCALL_DEFINE3(sigaction, int, sig, | |
3398 | const struct old_sigaction __user *, act, | |
3399 | struct old_sigaction __user *, oact) | |
3400 | { | |
3401 | struct k_sigaction new_ka, old_ka; | |
3402 | int ret; | |
3403 | ||
3404 | if (act) { | |
3405 | old_sigset_t mask; | |
3406 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3407 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
3408 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
3409 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3410 | __get_user(mask, &act->sa_mask)) | |
3411 | return -EFAULT; | |
3412 | #ifdef __ARCH_HAS_KA_RESTORER | |
3413 | new_ka.ka_restorer = NULL; | |
3414 | #endif | |
3415 | siginitset(&new_ka.sa.sa_mask, mask); | |
3416 | } | |
3417 | ||
3418 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3419 | ||
3420 | if (!ret && oact) { | |
3421 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3422 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
3423 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
3424 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3425 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3426 | return -EFAULT; | |
3427 | } | |
3428 | ||
3429 | return ret; | |
3430 | } | |
3431 | #endif | |
3432 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
3433 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
3434 | const struct compat_old_sigaction __user *, act, | |
3435 | struct compat_old_sigaction __user *, oact) | |
3436 | { | |
3437 | struct k_sigaction new_ka, old_ka; | |
3438 | int ret; | |
3439 | compat_old_sigset_t mask; | |
3440 | compat_uptr_t handler, restorer; | |
3441 | ||
3442 | if (act) { | |
3443 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3444 | __get_user(handler, &act->sa_handler) || | |
3445 | __get_user(restorer, &act->sa_restorer) || | |
3446 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3447 | __get_user(mask, &act->sa_mask)) | |
3448 | return -EFAULT; | |
3449 | ||
3450 | #ifdef __ARCH_HAS_KA_RESTORER | |
3451 | new_ka.ka_restorer = NULL; | |
3452 | #endif | |
3453 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3454 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3455 | siginitset(&new_ka.sa.sa_mask, mask); | |
3456 | } | |
3457 | ||
3458 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3459 | ||
3460 | if (!ret && oact) { | |
3461 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3462 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3463 | &oact->sa_handler) || | |
3464 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3465 | &oact->sa_restorer) || | |
3466 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3467 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3468 | return -EFAULT; | |
3469 | } | |
3470 | return ret; | |
3471 | } | |
3472 | #endif | |
1da177e4 | 3473 | |
f6187769 | 3474 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
3475 | |
3476 | /* | |
3477 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3478 | */ | |
a5f8fa9e | 3479 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3480 | { |
3481 | /* SMP safe */ | |
3482 | return current->blocked.sig[0]; | |
3483 | } | |
3484 | ||
a5f8fa9e | 3485 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3486 | { |
c1095c6d ON |
3487 | int old = current->blocked.sig[0]; |
3488 | sigset_t newset; | |
1da177e4 | 3489 | |
5ba53ff6 | 3490 | siginitset(&newset, newmask); |
c1095c6d | 3491 | set_current_blocked(&newset); |
1da177e4 LT |
3492 | |
3493 | return old; | |
3494 | } | |
f6187769 | 3495 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
3496 | |
3497 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3498 | /* | |
3499 | * For backwards compatibility. Functionality superseded by sigaction. | |
3500 | */ | |
a5f8fa9e | 3501 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3502 | { |
3503 | struct k_sigaction new_sa, old_sa; | |
3504 | int ret; | |
3505 | ||
3506 | new_sa.sa.sa_handler = handler; | |
3507 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3508 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3509 | |
3510 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3511 | ||
3512 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3513 | } | |
3514 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3515 | ||
3516 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3517 | ||
a5f8fa9e | 3518 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3519 | { |
d92fcf05 | 3520 | while (!signal_pending(current)) { |
1df01355 | 3521 | __set_current_state(TASK_INTERRUPTIBLE); |
d92fcf05 ON |
3522 | schedule(); |
3523 | } | |
1da177e4 LT |
3524 | return -ERESTARTNOHAND; |
3525 | } | |
3526 | ||
3527 | #endif | |
3528 | ||
9d8a7652 | 3529 | static int sigsuspend(sigset_t *set) |
68f3f16d | 3530 | { |
68f3f16d AV |
3531 | current->saved_sigmask = current->blocked; |
3532 | set_current_blocked(set); | |
3533 | ||
823dd322 SL |
3534 | while (!signal_pending(current)) { |
3535 | __set_current_state(TASK_INTERRUPTIBLE); | |
3536 | schedule(); | |
3537 | } | |
68f3f16d AV |
3538 | set_restore_sigmask(); |
3539 | return -ERESTARTNOHAND; | |
3540 | } | |
68f3f16d | 3541 | |
41c57892 RD |
3542 | /** |
3543 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3544 | * @unewset value until a signal is received | |
3545 | * @unewset: new signal mask value | |
3546 | * @sigsetsize: size of sigset_t type | |
3547 | */ | |
d4e82042 | 3548 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3549 | { |
3550 | sigset_t newset; | |
3551 | ||
3552 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3553 | if (sigsetsize != sizeof(sigset_t)) | |
3554 | return -EINVAL; | |
3555 | ||
3556 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3557 | return -EFAULT; | |
68f3f16d | 3558 | return sigsuspend(&newset); |
150256d8 | 3559 | } |
ad4b65a4 AV |
3560 | |
3561 | #ifdef CONFIG_COMPAT | |
3562 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
3563 | { | |
3564 | #ifdef __BIG_ENDIAN | |
3565 | sigset_t newset; | |
3566 | compat_sigset_t newset32; | |
3567 | ||
3568 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3569 | if (sigsetsize != sizeof(sigset_t)) | |
3570 | return -EINVAL; | |
3571 | ||
3572 | if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t))) | |
3573 | return -EFAULT; | |
3574 | sigset_from_compat(&newset, &newset32); | |
3575 | return sigsuspend(&newset); | |
3576 | #else | |
3577 | /* on little-endian bitmaps don't care about granularity */ | |
3578 | return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize); | |
3579 | #endif | |
3580 | } | |
3581 | #endif | |
150256d8 | 3582 | |
0a0e8cdf AV |
3583 | #ifdef CONFIG_OLD_SIGSUSPEND |
3584 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
3585 | { | |
3586 | sigset_t blocked; | |
3587 | siginitset(&blocked, mask); | |
3588 | return sigsuspend(&blocked); | |
3589 | } | |
3590 | #endif | |
3591 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
3592 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
3593 | { | |
3594 | sigset_t blocked; | |
3595 | siginitset(&blocked, mask); | |
3596 | return sigsuspend(&blocked); | |
3597 | } | |
3598 | #endif | |
150256d8 | 3599 | |
52f5684c | 3600 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
3601 | { |
3602 | return NULL; | |
3603 | } | |
3604 | ||
1da177e4 LT |
3605 | void __init signals_init(void) |
3606 | { | |
41b27154 HD |
3607 | /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */ |
3608 | BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE | |
3609 | != offsetof(struct siginfo, _sifields._pad)); | |
3610 | ||
0a31bd5f | 3611 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3612 | } |
67fc4e0c JW |
3613 | |
3614 | #ifdef CONFIG_KGDB_KDB | |
3615 | #include <linux/kdb.h> | |
3616 | /* | |
3617 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3618 | * signal internals. This function checks if the required locks are | |
3619 | * available before calling the main signal code, to avoid kdb | |
3620 | * deadlocks. | |
3621 | */ | |
3622 | void | |
3623 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3624 | { | |
3625 | static struct task_struct *kdb_prev_t; | |
3626 | int sig, new_t; | |
3627 | if (!spin_trylock(&t->sighand->siglock)) { | |
3628 | kdb_printf("Can't do kill command now.\n" | |
3629 | "The sigmask lock is held somewhere else in " | |
3630 | "kernel, try again later\n"); | |
3631 | return; | |
3632 | } | |
3633 | spin_unlock(&t->sighand->siglock); | |
3634 | new_t = kdb_prev_t != t; | |
3635 | kdb_prev_t = t; | |
3636 | if (t->state != TASK_RUNNING && new_t) { | |
3637 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3638 | "kdb risks deadlock\n" | |
3639 | "on the run queue locks. " | |
3640 | "The signal has _not_ been sent.\n" | |
3641 | "Reissue the kill command if you want to risk " | |
3642 | "the deadlock.\n"); | |
3643 | return; | |
3644 | } | |
3645 | sig = info->si_signo; | |
3646 | if (send_sig_info(sig, info, t)) | |
3647 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3648 | sig, t->pid); | |
3649 | else | |
3650 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3651 | } | |
3652 | #endif /* CONFIG_KGDB_KDB */ |