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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 | 15 | #include <linux/init.h> |
589ee628 | 16 | #include <linux/sched/mm.h> |
8703e8a4 | 17 | #include <linux/sched/user.h> |
b17b0153 | 18 | #include <linux/sched/debug.h> |
29930025 | 19 | #include <linux/sched/task.h> |
68db0cf1 | 20 | #include <linux/sched/task_stack.h> |
1da177e4 LT |
21 | #include <linux/fs.h> |
22 | #include <linux/tty.h> | |
23 | #include <linux/binfmts.h> | |
179899fd | 24 | #include <linux/coredump.h> |
1da177e4 LT |
25 | #include <linux/security.h> |
26 | #include <linux/syscalls.h> | |
27 | #include <linux/ptrace.h> | |
7ed20e1a | 28 | #include <linux/signal.h> |
fba2afaa | 29 | #include <linux/signalfd.h> |
f84d49b2 | 30 | #include <linux/ratelimit.h> |
35de254d | 31 | #include <linux/tracehook.h> |
c59ede7b | 32 | #include <linux/capability.h> |
7dfb7103 | 33 | #include <linux/freezer.h> |
84d73786 SB |
34 | #include <linux/pid_namespace.h> |
35 | #include <linux/nsproxy.h> | |
6b550f94 | 36 | #include <linux/user_namespace.h> |
0326f5a9 | 37 | #include <linux/uprobes.h> |
90268439 | 38 | #include <linux/compat.h> |
2b5faa4c | 39 | #include <linux/cn_proc.h> |
52f5684c GID |
40 | #include <linux/compiler.h> |
41 | ||
d1eb650f MH |
42 | #define CREATE_TRACE_POINTS |
43 | #include <trace/events/signal.h> | |
84d73786 | 44 | |
1da177e4 | 45 | #include <asm/param.h> |
7c0f6ba6 | 46 | #include <linux/uaccess.h> |
1da177e4 LT |
47 | #include <asm/unistd.h> |
48 | #include <asm/siginfo.h> | |
d550bbd4 | 49 | #include <asm/cacheflush.h> |
e1396065 | 50 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
51 | |
52 | /* | |
53 | * SLAB caches for signal bits. | |
54 | */ | |
55 | ||
e18b890b | 56 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 57 | |
f84d49b2 NO |
58 | int print_fatal_signals __read_mostly; |
59 | ||
35de254d | 60 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 61 | { |
35de254d RM |
62 | return t->sighand->action[sig - 1].sa.sa_handler; |
63 | } | |
93585eea | 64 | |
35de254d RM |
65 | static int sig_handler_ignored(void __user *handler, int sig) |
66 | { | |
93585eea | 67 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
68 | return handler == SIG_IGN || |
69 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
70 | } | |
1da177e4 | 71 | |
def8cf72 | 72 | static int sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 73 | { |
35de254d | 74 | void __user *handler; |
1da177e4 | 75 | |
f008faff ON |
76 | handler = sig_handler(t, sig); |
77 | ||
78 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
def8cf72 | 79 | handler == SIG_DFL && !force) |
f008faff ON |
80 | return 1; |
81 | ||
82 | return sig_handler_ignored(handler, sig); | |
83 | } | |
84 | ||
def8cf72 | 85 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 86 | { |
1da177e4 LT |
87 | /* |
88 | * Blocked signals are never ignored, since the | |
89 | * signal handler may change by the time it is | |
90 | * unblocked. | |
91 | */ | |
325d22df | 92 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
93 | return 0; |
94 | ||
def8cf72 | 95 | if (!sig_task_ignored(t, sig, force)) |
35de254d RM |
96 | return 0; |
97 | ||
98 | /* | |
99 | * Tracers may want to know about even ignored signals. | |
100 | */ | |
a288eecc | 101 | return !t->ptrace; |
1da177e4 LT |
102 | } |
103 | ||
104 | /* | |
105 | * Re-calculate pending state from the set of locally pending | |
106 | * signals, globally pending signals, and blocked signals. | |
107 | */ | |
108 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
109 | { | |
110 | unsigned long ready; | |
111 | long i; | |
112 | ||
113 | switch (_NSIG_WORDS) { | |
114 | default: | |
115 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
116 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
117 | break; | |
118 | ||
119 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
120 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
121 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
122 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
123 | break; | |
124 | ||
125 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
126 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
127 | break; | |
128 | ||
129 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
130 | } | |
131 | return ready != 0; | |
132 | } | |
133 | ||
134 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
135 | ||
7bb44ade | 136 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 137 | { |
3759a0d9 | 138 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 139 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 140 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 141 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
142 | return 1; |
143 | } | |
b74d0deb RM |
144 | /* |
145 | * We must never clear the flag in another thread, or in current | |
146 | * when it's possible the current syscall is returning -ERESTART*. | |
147 | * So we don't clear it here, and only callers who know they should do. | |
148 | */ | |
7bb44ade RM |
149 | return 0; |
150 | } | |
151 | ||
152 | /* | |
153 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
154 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
155 | */ | |
156 | void recalc_sigpending_and_wake(struct task_struct *t) | |
157 | { | |
158 | if (recalc_sigpending_tsk(t)) | |
159 | signal_wake_up(t, 0); | |
1da177e4 LT |
160 | } |
161 | ||
162 | void recalc_sigpending(void) | |
163 | { | |
dd1d6772 | 164 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
165 | clear_thread_flag(TIF_SIGPENDING); |
166 | ||
1da177e4 LT |
167 | } |
168 | ||
169 | /* Given the mask, find the first available signal that should be serviced. */ | |
170 | ||
a27341cd LT |
171 | #define SYNCHRONOUS_MASK \ |
172 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 173 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 174 | |
fba2afaa | 175 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
176 | { |
177 | unsigned long i, *s, *m, x; | |
178 | int sig = 0; | |
f84d49b2 | 179 | |
1da177e4 LT |
180 | s = pending->signal.sig; |
181 | m = mask->sig; | |
a27341cd LT |
182 | |
183 | /* | |
184 | * Handle the first word specially: it contains the | |
185 | * synchronous signals that need to be dequeued first. | |
186 | */ | |
187 | x = *s &~ *m; | |
188 | if (x) { | |
189 | if (x & SYNCHRONOUS_MASK) | |
190 | x &= SYNCHRONOUS_MASK; | |
191 | sig = ffz(~x) + 1; | |
192 | return sig; | |
193 | } | |
194 | ||
1da177e4 LT |
195 | switch (_NSIG_WORDS) { |
196 | default: | |
a27341cd LT |
197 | for (i = 1; i < _NSIG_WORDS; ++i) { |
198 | x = *++s &~ *++m; | |
199 | if (!x) | |
200 | continue; | |
201 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
202 | break; | |
203 | } | |
1da177e4 LT |
204 | break; |
205 | ||
a27341cd LT |
206 | case 2: |
207 | x = s[1] &~ m[1]; | |
208 | if (!x) | |
1da177e4 | 209 | break; |
a27341cd | 210 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
211 | break; |
212 | ||
a27341cd LT |
213 | case 1: |
214 | /* Nothing to do */ | |
1da177e4 LT |
215 | break; |
216 | } | |
f84d49b2 | 217 | |
1da177e4 LT |
218 | return sig; |
219 | } | |
220 | ||
f84d49b2 NO |
221 | static inline void print_dropped_signal(int sig) |
222 | { | |
223 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
224 | ||
225 | if (!print_fatal_signals) | |
226 | return; | |
227 | ||
228 | if (!__ratelimit(&ratelimit_state)) | |
229 | return; | |
230 | ||
747800ef | 231 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
f84d49b2 NO |
232 | current->comm, current->pid, sig); |
233 | } | |
234 | ||
d79fdd6d | 235 | /** |
7dd3db54 | 236 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 237 | * @task: target task |
7dd3db54 | 238 | * @mask: pending bits to set |
d79fdd6d | 239 | * |
7dd3db54 TH |
240 | * Clear @mask from @task->jobctl. @mask must be subset of |
241 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
242 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
243 | * cleared. If @task is already being killed or exiting, this function | |
244 | * becomes noop. | |
245 | * | |
246 | * CONTEXT: | |
247 | * Must be called with @task->sighand->siglock held. | |
248 | * | |
249 | * RETURNS: | |
250 | * %true if @mask is set, %false if made noop because @task was dying. | |
251 | */ | |
b76808e6 | 252 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
7dd3db54 TH |
253 | { |
254 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
255 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
256 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
257 | ||
258 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
259 | return false; | |
260 | ||
261 | if (mask & JOBCTL_STOP_SIGMASK) | |
262 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
263 | ||
264 | task->jobctl |= mask; | |
265 | return true; | |
266 | } | |
267 | ||
d79fdd6d | 268 | /** |
a8f072c1 | 269 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
270 | * @task: target task |
271 | * | |
a8f072c1 TH |
272 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
273 | * Clear it and wake up the ptracer. Note that we don't need any further | |
274 | * locking. @task->siglock guarantees that @task->parent points to the | |
275 | * ptracer. | |
d79fdd6d TH |
276 | * |
277 | * CONTEXT: | |
278 | * Must be called with @task->sighand->siglock held. | |
279 | */ | |
73ddff2b | 280 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 281 | { |
a8f072c1 TH |
282 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
283 | task->jobctl &= ~JOBCTL_TRAPPING; | |
650226bd | 284 | smp_mb(); /* advised by wake_up_bit() */ |
62c124ff | 285 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
286 | } |
287 | } | |
288 | ||
e5c1902e | 289 | /** |
3759a0d9 | 290 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 291 | * @task: target task |
3759a0d9 | 292 | * @mask: pending bits to clear |
e5c1902e | 293 | * |
3759a0d9 TH |
294 | * Clear @mask from @task->jobctl. @mask must be subset of |
295 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
296 | * STOP bits are cleared together. | |
e5c1902e | 297 | * |
6dfca329 TH |
298 | * If clearing of @mask leaves no stop or trap pending, this function calls |
299 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
300 | * |
301 | * CONTEXT: | |
302 | * Must be called with @task->sighand->siglock held. | |
303 | */ | |
b76808e6 | 304 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
e5c1902e | 305 | { |
3759a0d9 TH |
306 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
307 | ||
308 | if (mask & JOBCTL_STOP_PENDING) | |
309 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
310 | ||
311 | task->jobctl &= ~mask; | |
6dfca329 TH |
312 | |
313 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
314 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
315 | } |
316 | ||
317 | /** | |
318 | * task_participate_group_stop - participate in a group stop | |
319 | * @task: task participating in a group stop | |
320 | * | |
a8f072c1 | 321 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 322 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 323 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 324 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
325 | * |
326 | * CONTEXT: | |
327 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
328 | * |
329 | * RETURNS: | |
330 | * %true if group stop completion should be notified to the parent, %false | |
331 | * otherwise. | |
e5c1902e TH |
332 | */ |
333 | static bool task_participate_group_stop(struct task_struct *task) | |
334 | { | |
335 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 336 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 337 | |
a8f072c1 | 338 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 339 | |
3759a0d9 | 340 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
341 | |
342 | if (!consume) | |
343 | return false; | |
344 | ||
345 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
346 | sig->group_stop_count--; | |
347 | ||
244056f9 TH |
348 | /* |
349 | * Tell the caller to notify completion iff we are entering into a | |
350 | * fresh group stop. Read comment in do_signal_stop() for details. | |
351 | */ | |
352 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
2d39b3cd | 353 | signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
e5c1902e TH |
354 | return true; |
355 | } | |
356 | return false; | |
357 | } | |
358 | ||
c69e8d9c DH |
359 | /* |
360 | * allocate a new signal queue record | |
361 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 362 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 363 | */ |
f84d49b2 NO |
364 | static struct sigqueue * |
365 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
366 | { |
367 | struct sigqueue *q = NULL; | |
10b1fbdb | 368 | struct user_struct *user; |
1da177e4 | 369 | |
10b1fbdb | 370 | /* |
7cf7db8d TG |
371 | * Protect access to @t credentials. This can go away when all |
372 | * callers hold rcu read lock. | |
10b1fbdb | 373 | */ |
7cf7db8d | 374 | rcu_read_lock(); |
d84f4f99 | 375 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 376 | atomic_inc(&user->sigpending); |
7cf7db8d | 377 | rcu_read_unlock(); |
f84d49b2 | 378 | |
1da177e4 | 379 | if (override_rlimit || |
10b1fbdb | 380 | atomic_read(&user->sigpending) <= |
78d7d407 | 381 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 382 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
383 | } else { |
384 | print_dropped_signal(sig); | |
385 | } | |
386 | ||
1da177e4 | 387 | if (unlikely(q == NULL)) { |
10b1fbdb | 388 | atomic_dec(&user->sigpending); |
d84f4f99 | 389 | free_uid(user); |
1da177e4 LT |
390 | } else { |
391 | INIT_LIST_HEAD(&q->list); | |
392 | q->flags = 0; | |
d84f4f99 | 393 | q->user = user; |
1da177e4 | 394 | } |
d84f4f99 DH |
395 | |
396 | return q; | |
1da177e4 LT |
397 | } |
398 | ||
514a01b8 | 399 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
400 | { |
401 | if (q->flags & SIGQUEUE_PREALLOC) | |
402 | return; | |
403 | atomic_dec(&q->user->sigpending); | |
404 | free_uid(q->user); | |
405 | kmem_cache_free(sigqueue_cachep, q); | |
406 | } | |
407 | ||
6a14c5c9 | 408 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
409 | { |
410 | struct sigqueue *q; | |
411 | ||
412 | sigemptyset(&queue->signal); | |
413 | while (!list_empty(&queue->list)) { | |
414 | q = list_entry(queue->list.next, struct sigqueue , list); | |
415 | list_del_init(&q->list); | |
416 | __sigqueue_free(q); | |
417 | } | |
418 | } | |
419 | ||
420 | /* | |
9e7c8f8c | 421 | * Flush all pending signals for this kthread. |
1da177e4 | 422 | */ |
c81addc9 | 423 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
424 | { |
425 | unsigned long flags; | |
426 | ||
427 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
9e7c8f8c ON |
428 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
429 | flush_sigqueue(&t->pending); | |
430 | flush_sigqueue(&t->signal->shared_pending); | |
1da177e4 LT |
431 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
432 | } | |
433 | ||
baa73d9e | 434 | #ifdef CONFIG_POSIX_TIMERS |
cbaffba1 ON |
435 | static void __flush_itimer_signals(struct sigpending *pending) |
436 | { | |
437 | sigset_t signal, retain; | |
438 | struct sigqueue *q, *n; | |
439 | ||
440 | signal = pending->signal; | |
441 | sigemptyset(&retain); | |
442 | ||
443 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
444 | int sig = q->info.si_signo; | |
445 | ||
446 | if (likely(q->info.si_code != SI_TIMER)) { | |
447 | sigaddset(&retain, sig); | |
448 | } else { | |
449 | sigdelset(&signal, sig); | |
450 | list_del_init(&q->list); | |
451 | __sigqueue_free(q); | |
452 | } | |
453 | } | |
454 | ||
455 | sigorsets(&pending->signal, &signal, &retain); | |
456 | } | |
457 | ||
458 | void flush_itimer_signals(void) | |
459 | { | |
460 | struct task_struct *tsk = current; | |
461 | unsigned long flags; | |
462 | ||
463 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
464 | __flush_itimer_signals(&tsk->pending); | |
465 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
466 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
467 | } | |
baa73d9e | 468 | #endif |
cbaffba1 | 469 | |
10ab825b ON |
470 | void ignore_signals(struct task_struct *t) |
471 | { | |
472 | int i; | |
473 | ||
474 | for (i = 0; i < _NSIG; ++i) | |
475 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
476 | ||
477 | flush_signals(t); | |
478 | } | |
479 | ||
1da177e4 LT |
480 | /* |
481 | * Flush all handlers for a task. | |
482 | */ | |
483 | ||
484 | void | |
485 | flush_signal_handlers(struct task_struct *t, int force_default) | |
486 | { | |
487 | int i; | |
488 | struct k_sigaction *ka = &t->sighand->action[0]; | |
489 | for (i = _NSIG ; i != 0 ; i--) { | |
490 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
491 | ka->sa.sa_handler = SIG_DFL; | |
492 | ka->sa.sa_flags = 0; | |
522cff14 | 493 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
494 | ka->sa.sa_restorer = NULL; |
495 | #endif | |
1da177e4 LT |
496 | sigemptyset(&ka->sa.sa_mask); |
497 | ka++; | |
498 | } | |
499 | } | |
500 | ||
abd4f750 MAS |
501 | int unhandled_signal(struct task_struct *tsk, int sig) |
502 | { | |
445a91d2 | 503 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 504 | if (is_global_init(tsk)) |
abd4f750 | 505 | return 1; |
445a91d2 | 506 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 507 | return 0; |
a288eecc TH |
508 | /* if ptraced, let the tracer determine */ |
509 | return !tsk->ptrace; | |
abd4f750 MAS |
510 | } |
511 | ||
100360f0 | 512 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
513 | { |
514 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 515 | |
1da177e4 LT |
516 | /* |
517 | * Collect the siginfo appropriate to this signal. Check if | |
518 | * there is another siginfo for the same signal. | |
519 | */ | |
520 | list_for_each_entry(q, &list->list, list) { | |
521 | if (q->info.si_signo == sig) { | |
d4434207 ON |
522 | if (first) |
523 | goto still_pending; | |
1da177e4 LT |
524 | first = q; |
525 | } | |
526 | } | |
d4434207 ON |
527 | |
528 | sigdelset(&list->signal, sig); | |
529 | ||
1da177e4 | 530 | if (first) { |
d4434207 | 531 | still_pending: |
1da177e4 LT |
532 | list_del_init(&first->list); |
533 | copy_siginfo(info, &first->info); | |
534 | __sigqueue_free(first); | |
1da177e4 | 535 | } else { |
5aba085e RD |
536 | /* |
537 | * Ok, it wasn't in the queue. This must be | |
538 | * a fast-pathed signal or we must have been | |
539 | * out of queue space. So zero out the info. | |
1da177e4 | 540 | */ |
1da177e4 LT |
541 | info->si_signo = sig; |
542 | info->si_errno = 0; | |
7486e5d9 | 543 | info->si_code = SI_USER; |
1da177e4 LT |
544 | info->si_pid = 0; |
545 | info->si_uid = 0; | |
546 | } | |
1da177e4 LT |
547 | } |
548 | ||
549 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
550 | siginfo_t *info) | |
551 | { | |
27d91e07 | 552 | int sig = next_signal(pending, mask); |
1da177e4 | 553 | |
2e01fabe | 554 | if (sig) |
100360f0 | 555 | collect_signal(sig, pending, info); |
1da177e4 LT |
556 | return sig; |
557 | } | |
558 | ||
559 | /* | |
5aba085e | 560 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
561 | * expected to free it. |
562 | * | |
563 | * All callers have to hold the siglock. | |
564 | */ | |
565 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
566 | { | |
c5363d03 | 567 | int signr; |
caec4e8d BH |
568 | |
569 | /* We only dequeue private signals from ourselves, we don't let | |
570 | * signalfd steal them | |
571 | */ | |
b8fceee1 | 572 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 573 | if (!signr) { |
1da177e4 LT |
574 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
575 | mask, info); | |
baa73d9e | 576 | #ifdef CONFIG_POSIX_TIMERS |
8bfd9a7a TG |
577 | /* |
578 | * itimer signal ? | |
579 | * | |
580 | * itimers are process shared and we restart periodic | |
581 | * itimers in the signal delivery path to prevent DoS | |
582 | * attacks in the high resolution timer case. This is | |
5aba085e | 583 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
584 | * itimers, as the SIGALRM is a legacy signal and only |
585 | * queued once. Changing the restart behaviour to | |
586 | * restart the timer in the signal dequeue path is | |
587 | * reducing the timer noise on heavy loaded !highres | |
588 | * systems too. | |
589 | */ | |
590 | if (unlikely(signr == SIGALRM)) { | |
591 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
592 | ||
593 | if (!hrtimer_is_queued(tmr) && | |
2456e855 | 594 | tsk->signal->it_real_incr != 0) { |
8bfd9a7a TG |
595 | hrtimer_forward(tmr, tmr->base->get_time(), |
596 | tsk->signal->it_real_incr); | |
597 | hrtimer_restart(tmr); | |
598 | } | |
599 | } | |
baa73d9e | 600 | #endif |
8bfd9a7a | 601 | } |
c5363d03 | 602 | |
b8fceee1 | 603 | recalc_sigpending(); |
c5363d03 PE |
604 | if (!signr) |
605 | return 0; | |
606 | ||
607 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
608 | /* |
609 | * Set a marker that we have dequeued a stop signal. Our | |
610 | * caller might release the siglock and then the pending | |
611 | * stop signal it is about to process is no longer in the | |
612 | * pending bitmasks, but must still be cleared by a SIGCONT | |
613 | * (and overruled by a SIGKILL). So those cases clear this | |
614 | * shared flag after we've set it. Note that this flag may | |
615 | * remain set after the signal we return is ignored or | |
616 | * handled. That doesn't matter because its only purpose | |
617 | * is to alert stop-signal processing code when another | |
618 | * processor has come along and cleared the flag. | |
619 | */ | |
a8f072c1 | 620 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 621 | } |
baa73d9e | 622 | #ifdef CONFIG_POSIX_TIMERS |
c5363d03 | 623 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { |
1da177e4 LT |
624 | /* |
625 | * Release the siglock to ensure proper locking order | |
626 | * of timer locks outside of siglocks. Note, we leave | |
627 | * irqs disabled here, since the posix-timers code is | |
628 | * about to disable them again anyway. | |
629 | */ | |
630 | spin_unlock(&tsk->sighand->siglock); | |
631 | do_schedule_next_timer(info); | |
632 | spin_lock(&tsk->sighand->siglock); | |
633 | } | |
baa73d9e | 634 | #endif |
1da177e4 LT |
635 | return signr; |
636 | } | |
637 | ||
638 | /* | |
639 | * Tell a process that it has a new active signal.. | |
640 | * | |
641 | * NOTE! we rely on the previous spin_lock to | |
642 | * lock interrupts for us! We can only be called with | |
643 | * "siglock" held, and the local interrupt must | |
644 | * have been disabled when that got acquired! | |
645 | * | |
646 | * No need to set need_resched since signal event passing | |
647 | * goes through ->blocked | |
648 | */ | |
910ffdb1 | 649 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 650 | { |
1da177e4 | 651 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 652 | /* |
910ffdb1 | 653 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 654 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
655 | * executing another processor and just now entering stopped state. |
656 | * By using wake_up_state, we ensure the process will wake up and | |
657 | * handle its death signal. | |
658 | */ | |
910ffdb1 | 659 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
660 | kick_process(t); |
661 | } | |
662 | ||
71fabd5e GA |
663 | /* |
664 | * Remove signals in mask from the pending set and queue. | |
665 | * Returns 1 if any signals were found. | |
666 | * | |
667 | * All callers must be holding the siglock. | |
71fabd5e | 668 | */ |
c09c1441 | 669 | static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
71fabd5e GA |
670 | { |
671 | struct sigqueue *q, *n; | |
672 | sigset_t m; | |
673 | ||
674 | sigandsets(&m, mask, &s->signal); | |
675 | if (sigisemptyset(&m)) | |
676 | return 0; | |
677 | ||
702a5073 | 678 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
679 | list_for_each_entry_safe(q, n, &s->list, list) { |
680 | if (sigismember(mask, q->info.si_signo)) { | |
681 | list_del_init(&q->list); | |
682 | __sigqueue_free(q); | |
683 | } | |
684 | } | |
685 | return 1; | |
686 | } | |
1da177e4 | 687 | |
614c517d ON |
688 | static inline int is_si_special(const struct siginfo *info) |
689 | { | |
690 | return info <= SEND_SIG_FORCED; | |
691 | } | |
692 | ||
693 | static inline bool si_fromuser(const struct siginfo *info) | |
694 | { | |
695 | return info == SEND_SIG_NOINFO || | |
696 | (!is_si_special(info) && SI_FROMUSER(info)); | |
697 | } | |
698 | ||
39fd3393 SH |
699 | /* |
700 | * called with RCU read lock from check_kill_permission() | |
701 | */ | |
702 | static int kill_ok_by_cred(struct task_struct *t) | |
703 | { | |
704 | const struct cred *cred = current_cred(); | |
705 | const struct cred *tcred = __task_cred(t); | |
706 | ||
5af66203 EB |
707 | if (uid_eq(cred->euid, tcred->suid) || |
708 | uid_eq(cred->euid, tcred->uid) || | |
709 | uid_eq(cred->uid, tcred->suid) || | |
710 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
711 | return 1; |
712 | ||
c4a4d603 | 713 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
714 | return 1; |
715 | ||
716 | return 0; | |
717 | } | |
718 | ||
1da177e4 LT |
719 | /* |
720 | * Bad permissions for sending the signal | |
694f690d | 721 | * - the caller must hold the RCU read lock |
1da177e4 LT |
722 | */ |
723 | static int check_kill_permission(int sig, struct siginfo *info, | |
724 | struct task_struct *t) | |
725 | { | |
2e2ba22e | 726 | struct pid *sid; |
3b5e9e53 ON |
727 | int error; |
728 | ||
7ed20e1a | 729 | if (!valid_signal(sig)) |
3b5e9e53 ON |
730 | return -EINVAL; |
731 | ||
614c517d | 732 | if (!si_fromuser(info)) |
3b5e9e53 | 733 | return 0; |
e54dc243 | 734 | |
3b5e9e53 ON |
735 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
736 | if (error) | |
1da177e4 | 737 | return error; |
3b5e9e53 | 738 | |
065add39 | 739 | if (!same_thread_group(current, t) && |
39fd3393 | 740 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
741 | switch (sig) { |
742 | case SIGCONT: | |
2e2ba22e | 743 | sid = task_session(t); |
2e2ba22e ON |
744 | /* |
745 | * We don't return the error if sid == NULL. The | |
746 | * task was unhashed, the caller must notice this. | |
747 | */ | |
748 | if (!sid || sid == task_session(current)) | |
749 | break; | |
750 | default: | |
751 | return -EPERM; | |
752 | } | |
753 | } | |
c2f0c7c3 | 754 | |
e54dc243 | 755 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
756 | } |
757 | ||
fb1d910c TH |
758 | /** |
759 | * ptrace_trap_notify - schedule trap to notify ptracer | |
760 | * @t: tracee wanting to notify tracer | |
761 | * | |
762 | * This function schedules sticky ptrace trap which is cleared on the next | |
763 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
764 | * ptracer. | |
765 | * | |
544b2c91 TH |
766 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
767 | * ptracer is listening for events, tracee is woken up so that it can | |
768 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
769 | * eventually taken without returning to userland after the existing traps | |
770 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
771 | * |
772 | * CONTEXT: | |
773 | * Must be called with @task->sighand->siglock held. | |
774 | */ | |
775 | static void ptrace_trap_notify(struct task_struct *t) | |
776 | { | |
777 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
778 | assert_spin_locked(&t->sighand->siglock); | |
779 | ||
780 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 781 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
782 | } |
783 | ||
1da177e4 | 784 | /* |
7e695a5e ON |
785 | * Handle magic process-wide effects of stop/continue signals. Unlike |
786 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
787 | * time regardless of blocking, ignoring, or handling. This does the |
788 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
789 | * signals. The process stop is done as a signal action for SIG_DFL. |
790 | * | |
791 | * Returns true if the signal should be actually delivered, otherwise | |
792 | * it should be dropped. | |
1da177e4 | 793 | */ |
403bad72 | 794 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 795 | { |
ad16a460 | 796 | struct signal_struct *signal = p->signal; |
1da177e4 | 797 | struct task_struct *t; |
9490592f | 798 | sigset_t flush; |
1da177e4 | 799 | |
403bad72 | 800 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { |
5fa534c9 | 801 | if (!(signal->flags & SIGNAL_GROUP_EXIT)) |
403bad72 | 802 | return sig == SIGKILL; |
1da177e4 | 803 | /* |
7e695a5e | 804 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 805 | */ |
7e695a5e | 806 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
807 | /* |
808 | * This is a stop signal. Remove SIGCONT from all queues. | |
809 | */ | |
9490592f | 810 | siginitset(&flush, sigmask(SIGCONT)); |
c09c1441 | 811 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 812 | for_each_thread(p, t) |
c09c1441 | 813 | flush_sigqueue_mask(&flush, &t->pending); |
1da177e4 | 814 | } else if (sig == SIGCONT) { |
fc321d2e | 815 | unsigned int why; |
1da177e4 | 816 | /* |
1deac632 | 817 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 818 | */ |
9490592f | 819 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
c09c1441 | 820 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 821 | for_each_thread(p, t) { |
c09c1441 | 822 | flush_sigqueue_mask(&flush, &t->pending); |
3759a0d9 | 823 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
fb1d910c TH |
824 | if (likely(!(t->ptrace & PT_SEIZED))) |
825 | wake_up_state(t, __TASK_STOPPED); | |
826 | else | |
827 | ptrace_trap_notify(t); | |
9490592f | 828 | } |
1da177e4 | 829 | |
fc321d2e ON |
830 | /* |
831 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
832 | * | |
833 | * If we were in the middle of a group stop, we pretend it | |
834 | * was already finished, and then continued. Since SIGCHLD | |
835 | * doesn't queue we report only CLD_STOPPED, as if the next | |
836 | * CLD_CONTINUED was dropped. | |
837 | */ | |
838 | why = 0; | |
ad16a460 | 839 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 840 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 841 | else if (signal->group_stop_count) |
fc321d2e ON |
842 | why |= SIGNAL_CLD_STOPPED; |
843 | ||
844 | if (why) { | |
021e1ae3 | 845 | /* |
ae6d2ed7 | 846 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
847 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
848 | * notify its parent. See get_signal_to_deliver(). | |
849 | */ | |
2d39b3cd | 850 | signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
ad16a460 ON |
851 | signal->group_stop_count = 0; |
852 | signal->group_exit_code = 0; | |
1da177e4 | 853 | } |
1da177e4 | 854 | } |
7e695a5e | 855 | |
def8cf72 | 856 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
857 | } |
858 | ||
71f11dc0 ON |
859 | /* |
860 | * Test if P wants to take SIG. After we've checked all threads with this, | |
861 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
862 | * blocking SIG were ruled out because they are not running and already | |
863 | * have pending signals. Such threads will dequeue from the shared queue | |
864 | * as soon as they're available, so putting the signal on the shared queue | |
865 | * will be equivalent to sending it to one such thread. | |
866 | */ | |
867 | static inline int wants_signal(int sig, struct task_struct *p) | |
868 | { | |
869 | if (sigismember(&p->blocked, sig)) | |
870 | return 0; | |
871 | if (p->flags & PF_EXITING) | |
872 | return 0; | |
873 | if (sig == SIGKILL) | |
874 | return 1; | |
875 | if (task_is_stopped_or_traced(p)) | |
876 | return 0; | |
877 | return task_curr(p) || !signal_pending(p); | |
878 | } | |
879 | ||
5fcd835b | 880 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
881 | { |
882 | struct signal_struct *signal = p->signal; | |
883 | struct task_struct *t; | |
884 | ||
885 | /* | |
886 | * Now find a thread we can wake up to take the signal off the queue. | |
887 | * | |
888 | * If the main thread wants the signal, it gets first crack. | |
889 | * Probably the least surprising to the average bear. | |
890 | */ | |
891 | if (wants_signal(sig, p)) | |
892 | t = p; | |
5fcd835b | 893 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
894 | /* |
895 | * There is just one thread and it does not need to be woken. | |
896 | * It will dequeue unblocked signals before it runs again. | |
897 | */ | |
898 | return; | |
899 | else { | |
900 | /* | |
901 | * Otherwise try to find a suitable thread. | |
902 | */ | |
903 | t = signal->curr_target; | |
904 | while (!wants_signal(sig, t)) { | |
905 | t = next_thread(t); | |
906 | if (t == signal->curr_target) | |
907 | /* | |
908 | * No thread needs to be woken. | |
909 | * Any eligible threads will see | |
910 | * the signal in the queue soon. | |
911 | */ | |
912 | return; | |
913 | } | |
914 | signal->curr_target = t; | |
915 | } | |
916 | ||
917 | /* | |
918 | * Found a killable thread. If the signal will be fatal, | |
919 | * then start taking the whole group down immediately. | |
920 | */ | |
fae5fa44 ON |
921 | if (sig_fatal(p, sig) && |
922 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 923 | !sigismember(&t->real_blocked, sig) && |
a288eecc | 924 | (sig == SIGKILL || !t->ptrace)) { |
71f11dc0 ON |
925 | /* |
926 | * This signal will be fatal to the whole group. | |
927 | */ | |
928 | if (!sig_kernel_coredump(sig)) { | |
929 | /* | |
930 | * Start a group exit and wake everybody up. | |
931 | * This way we don't have other threads | |
932 | * running and doing things after a slower | |
933 | * thread has the fatal signal pending. | |
934 | */ | |
935 | signal->flags = SIGNAL_GROUP_EXIT; | |
936 | signal->group_exit_code = sig; | |
937 | signal->group_stop_count = 0; | |
938 | t = p; | |
939 | do { | |
6dfca329 | 940 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
941 | sigaddset(&t->pending.signal, SIGKILL); |
942 | signal_wake_up(t, 1); | |
943 | } while_each_thread(p, t); | |
944 | return; | |
945 | } | |
946 | } | |
947 | ||
948 | /* | |
949 | * The signal is already in the shared-pending queue. | |
950 | * Tell the chosen thread to wake up and dequeue it. | |
951 | */ | |
952 | signal_wake_up(t, sig == SIGKILL); | |
953 | return; | |
954 | } | |
955 | ||
af7fff9c PE |
956 | static inline int legacy_queue(struct sigpending *signals, int sig) |
957 | { | |
958 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
959 | } | |
960 | ||
6b550f94 SH |
961 | #ifdef CONFIG_USER_NS |
962 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
963 | { | |
964 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
965 | return; | |
966 | ||
967 | if (SI_FROMKERNEL(info)) | |
968 | return; | |
969 | ||
078de5f7 EB |
970 | rcu_read_lock(); |
971 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
972 | make_kuid(current_user_ns(), info->si_uid)); | |
973 | rcu_read_unlock(); | |
6b550f94 SH |
974 | } |
975 | #else | |
976 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
977 | { | |
978 | return; | |
979 | } | |
980 | #endif | |
981 | ||
7978b567 SB |
982 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
983 | int group, int from_ancestor_ns) | |
1da177e4 | 984 | { |
2ca3515a | 985 | struct sigpending *pending; |
6e65acba | 986 | struct sigqueue *q; |
7a0aeb14 | 987 | int override_rlimit; |
6c303d3a | 988 | int ret = 0, result; |
0a16b607 | 989 | |
6e65acba | 990 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 991 | |
6c303d3a | 992 | result = TRACE_SIGNAL_IGNORED; |
629d362b ON |
993 | if (!prepare_signal(sig, t, |
994 | from_ancestor_ns || (info == SEND_SIG_FORCED))) | |
6c303d3a | 995 | goto ret; |
2ca3515a ON |
996 | |
997 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
998 | /* |
999 | * Short-circuit ignored signals and support queuing | |
1000 | * exactly one non-rt signal, so that we can get more | |
1001 | * detailed information about the cause of the signal. | |
1002 | */ | |
6c303d3a | 1003 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1004 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1005 | goto ret; |
1006 | ||
1007 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1008 | /* |
1009 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1010 | * or SIGKILL. | |
1011 | */ | |
b67a1b9e | 1012 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1013 | goto out_set; |
1014 | ||
5aba085e RD |
1015 | /* |
1016 | * Real-time signals must be queued if sent by sigqueue, or | |
1017 | * some other real-time mechanism. It is implementation | |
1018 | * defined whether kill() does so. We attempt to do so, on | |
1019 | * the principle of least surprise, but since kill is not | |
1020 | * allowed to fail with EAGAIN when low on memory we just | |
1021 | * make sure at least one signal gets delivered and don't | |
1022 | * pass on the info struct. | |
1023 | */ | |
7a0aeb14 VN |
1024 | if (sig < SIGRTMIN) |
1025 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1026 | else | |
1027 | override_rlimit = 0; | |
1028 | ||
f84d49b2 | 1029 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1030 | override_rlimit); |
1da177e4 | 1031 | if (q) { |
2ca3515a | 1032 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1033 | switch ((unsigned long) info) { |
b67a1b9e | 1034 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1035 | q->info.si_signo = sig; |
1036 | q->info.si_errno = 0; | |
1037 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1038 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1039 | task_active_pid_ns(t)); |
078de5f7 | 1040 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1041 | break; |
b67a1b9e | 1042 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1043 | q->info.si_signo = sig; |
1044 | q->info.si_errno = 0; | |
1045 | q->info.si_code = SI_KERNEL; | |
1046 | q->info.si_pid = 0; | |
1047 | q->info.si_uid = 0; | |
1048 | break; | |
1049 | default: | |
1050 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1051 | if (from_ancestor_ns) |
1052 | q->info.si_pid = 0; | |
1da177e4 LT |
1053 | break; |
1054 | } | |
6b550f94 SH |
1055 | |
1056 | userns_fixup_signal_uid(&q->info, t); | |
1057 | ||
621d3121 | 1058 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1059 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1060 | /* | |
1061 | * Queue overflow, abort. We may abort if the | |
1062 | * signal was rt and sent by user using something | |
1063 | * other than kill(). | |
1064 | */ | |
6c303d3a ON |
1065 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1066 | ret = -EAGAIN; | |
1067 | goto ret; | |
ba005e1f MH |
1068 | } else { |
1069 | /* | |
1070 | * This is a silent loss of information. We still | |
1071 | * send the signal, but the *info bits are lost. | |
1072 | */ | |
6c303d3a | 1073 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1074 | } |
1da177e4 LT |
1075 | } |
1076 | ||
1077 | out_set: | |
53c30337 | 1078 | signalfd_notify(t, sig); |
2ca3515a | 1079 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1080 | complete_signal(sig, t, group); |
6c303d3a ON |
1081 | ret: |
1082 | trace_signal_generate(sig, info, t, group, result); | |
1083 | return ret; | |
1da177e4 LT |
1084 | } |
1085 | ||
7978b567 SB |
1086 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1087 | int group) | |
1088 | { | |
921cf9f6 SB |
1089 | int from_ancestor_ns = 0; |
1090 | ||
1091 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1092 | from_ancestor_ns = si_fromuser(info) && |
1093 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1094 | #endif |
1095 | ||
1096 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1097 | } |
1098 | ||
4aaefee5 | 1099 | static void print_fatal_signal(int signr) |
45807a1d | 1100 | { |
4aaefee5 | 1101 | struct pt_regs *regs = signal_pt_regs(); |
747800ef | 1102 | pr_info("potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1103 | |
ca5cd877 | 1104 | #if defined(__i386__) && !defined(__arch_um__) |
747800ef | 1105 | pr_info("code at %08lx: ", regs->ip); |
45807a1d IM |
1106 | { |
1107 | int i; | |
1108 | for (i = 0; i < 16; i++) { | |
1109 | unsigned char insn; | |
1110 | ||
b45c6e76 AK |
1111 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1112 | break; | |
747800ef | 1113 | pr_cont("%02x ", insn); |
45807a1d IM |
1114 | } |
1115 | } | |
747800ef | 1116 | pr_cont("\n"); |
45807a1d | 1117 | #endif |
3a9f84d3 | 1118 | preempt_disable(); |
45807a1d | 1119 | show_regs(regs); |
3a9f84d3 | 1120 | preempt_enable(); |
45807a1d IM |
1121 | } |
1122 | ||
1123 | static int __init setup_print_fatal_signals(char *str) | |
1124 | { | |
1125 | get_option (&str, &print_fatal_signals); | |
1126 | ||
1127 | return 1; | |
1128 | } | |
1129 | ||
1130 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1131 | |
4cd4b6d4 PE |
1132 | int |
1133 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1134 | { | |
1135 | return send_signal(sig, info, p, 1); | |
1136 | } | |
1137 | ||
1da177e4 LT |
1138 | static int |
1139 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1140 | { | |
4cd4b6d4 | 1141 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1142 | } |
1143 | ||
4a30debf ON |
1144 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1145 | bool group) | |
1146 | { | |
1147 | unsigned long flags; | |
1148 | int ret = -ESRCH; | |
1149 | ||
1150 | if (lock_task_sighand(p, &flags)) { | |
1151 | ret = send_signal(sig, info, p, group); | |
1152 | unlock_task_sighand(p, &flags); | |
1153 | } | |
1154 | ||
1155 | return ret; | |
1156 | } | |
1157 | ||
1da177e4 LT |
1158 | /* |
1159 | * Force a signal that the process can't ignore: if necessary | |
1160 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1161 | * |
1162 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1163 | * since we do not want to have a signal handler that was blocked | |
1164 | * be invoked when user space had explicitly blocked it. | |
1165 | * | |
80fe728d ON |
1166 | * We don't want to have recursive SIGSEGV's etc, for example, |
1167 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1168 | */ |
1da177e4 LT |
1169 | int |
1170 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1171 | { | |
1172 | unsigned long int flags; | |
ae74c3b6 LT |
1173 | int ret, blocked, ignored; |
1174 | struct k_sigaction *action; | |
1da177e4 LT |
1175 | |
1176 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1177 | action = &t->sighand->action[sig-1]; |
1178 | ignored = action->sa.sa_handler == SIG_IGN; | |
1179 | blocked = sigismember(&t->blocked, sig); | |
1180 | if (blocked || ignored) { | |
1181 | action->sa.sa_handler = SIG_DFL; | |
1182 | if (blocked) { | |
1183 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1184 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1185 | } |
1da177e4 | 1186 | } |
80fe728d ON |
1187 | if (action->sa.sa_handler == SIG_DFL) |
1188 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1189 | ret = specific_send_sig_info(sig, info, t); |
1190 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1191 | ||
1192 | return ret; | |
1193 | } | |
1194 | ||
1da177e4 LT |
1195 | /* |
1196 | * Nuke all other threads in the group. | |
1197 | */ | |
09faef11 | 1198 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1199 | { |
09faef11 ON |
1200 | struct task_struct *t = p; |
1201 | int count = 0; | |
1da177e4 | 1202 | |
1da177e4 LT |
1203 | p->signal->group_stop_count = 0; |
1204 | ||
09faef11 | 1205 | while_each_thread(p, t) { |
6dfca329 | 1206 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1207 | count++; |
1208 | ||
1209 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1210 | if (t->exit_state) |
1211 | continue; | |
1da177e4 | 1212 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1213 | signal_wake_up(t, 1); |
1214 | } | |
09faef11 ON |
1215 | |
1216 | return count; | |
1da177e4 LT |
1217 | } |
1218 | ||
b8ed374e NK |
1219 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1220 | unsigned long *flags) | |
f63ee72e ON |
1221 | { |
1222 | struct sighand_struct *sighand; | |
1223 | ||
1224 | for (;;) { | |
c41247e1 PM |
1225 | /* |
1226 | * Disable interrupts early to avoid deadlocks. | |
1227 | * See rcu_read_unlock() comment header for details. | |
1228 | */ | |
a841796f PM |
1229 | local_irq_save(*flags); |
1230 | rcu_read_lock(); | |
f63ee72e | 1231 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1232 | if (unlikely(sighand == NULL)) { |
1233 | rcu_read_unlock(); | |
1234 | local_irq_restore(*flags); | |
f63ee72e | 1235 | break; |
a841796f | 1236 | } |
392809b2 ON |
1237 | /* |
1238 | * This sighand can be already freed and even reused, but | |
1239 | * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which | |
1240 | * initializes ->siglock: this slab can't go away, it has | |
1241 | * the same object type, ->siglock can't be reinitialized. | |
1242 | * | |
1243 | * We need to ensure that tsk->sighand is still the same | |
1244 | * after we take the lock, we can race with de_thread() or | |
1245 | * __exit_signal(). In the latter case the next iteration | |
1246 | * must see ->sighand == NULL. | |
1247 | */ | |
a841796f PM |
1248 | spin_lock(&sighand->siglock); |
1249 | if (likely(sighand == tsk->sighand)) { | |
1250 | rcu_read_unlock(); | |
f63ee72e | 1251 | break; |
a841796f PM |
1252 | } |
1253 | spin_unlock(&sighand->siglock); | |
1254 | rcu_read_unlock(); | |
1255 | local_irq_restore(*flags); | |
f63ee72e ON |
1256 | } |
1257 | ||
1258 | return sighand; | |
1259 | } | |
1260 | ||
c69e8d9c DH |
1261 | /* |
1262 | * send signal info to all the members of a group | |
c69e8d9c | 1263 | */ |
1da177e4 LT |
1264 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1265 | { | |
694f690d DH |
1266 | int ret; |
1267 | ||
1268 | rcu_read_lock(); | |
1269 | ret = check_kill_permission(sig, info, p); | |
1270 | rcu_read_unlock(); | |
f63ee72e | 1271 | |
4a30debf ON |
1272 | if (!ret && sig) |
1273 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1274 | |
1275 | return ret; | |
1276 | } | |
1277 | ||
1278 | /* | |
146a505d | 1279 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1280 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1281 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1282 | */ |
c4b92fc1 | 1283 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1284 | { |
1285 | struct task_struct *p = NULL; | |
1286 | int retval, success; | |
1287 | ||
1da177e4 LT |
1288 | success = 0; |
1289 | retval = -ESRCH; | |
c4b92fc1 | 1290 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1291 | int err = group_send_sig_info(sig, info, p); |
1292 | success |= !err; | |
1293 | retval = err; | |
c4b92fc1 | 1294 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1295 | return success ? 0 : retval; |
1296 | } | |
1297 | ||
c4b92fc1 | 1298 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1299 | { |
d36174bc | 1300 | int error = -ESRCH; |
1da177e4 LT |
1301 | struct task_struct *p; |
1302 | ||
eca1a089 PM |
1303 | for (;;) { |
1304 | rcu_read_lock(); | |
1305 | p = pid_task(pid, PIDTYPE_PID); | |
1306 | if (p) | |
1307 | error = group_send_sig_info(sig, info, p); | |
1308 | rcu_read_unlock(); | |
1309 | if (likely(!p || error != -ESRCH)) | |
1310 | return error; | |
6ca25b55 | 1311 | |
eca1a089 PM |
1312 | /* |
1313 | * The task was unhashed in between, try again. If it | |
1314 | * is dead, pid_task() will return NULL, if we race with | |
1315 | * de_thread() it will find the new leader. | |
1316 | */ | |
1317 | } | |
1da177e4 LT |
1318 | } |
1319 | ||
5aba085e | 1320 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1321 | { |
1322 | int error; | |
1323 | rcu_read_lock(); | |
b488893a | 1324 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1325 | rcu_read_unlock(); |
1326 | return error; | |
1327 | } | |
1328 | ||
d178bc3a SH |
1329 | static int kill_as_cred_perm(const struct cred *cred, |
1330 | struct task_struct *target) | |
1331 | { | |
1332 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1333 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1334 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1335 | return 0; |
1336 | return 1; | |
1337 | } | |
1338 | ||
2425c08b | 1339 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1340 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1341 | const struct cred *cred, u32 secid) | |
46113830 HW |
1342 | { |
1343 | int ret = -EINVAL; | |
1344 | struct task_struct *p; | |
14d8c9f3 | 1345 | unsigned long flags; |
46113830 HW |
1346 | |
1347 | if (!valid_signal(sig)) | |
1348 | return ret; | |
1349 | ||
14d8c9f3 | 1350 | rcu_read_lock(); |
2425c08b | 1351 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1352 | if (!p) { |
1353 | ret = -ESRCH; | |
1354 | goto out_unlock; | |
1355 | } | |
d178bc3a | 1356 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1357 | ret = -EPERM; |
1358 | goto out_unlock; | |
1359 | } | |
8f95dc58 DQ |
1360 | ret = security_task_kill(p, info, sig, secid); |
1361 | if (ret) | |
1362 | goto out_unlock; | |
14d8c9f3 TG |
1363 | |
1364 | if (sig) { | |
1365 | if (lock_task_sighand(p, &flags)) { | |
1366 | ret = __send_signal(sig, info, p, 1, 0); | |
1367 | unlock_task_sighand(p, &flags); | |
1368 | } else | |
1369 | ret = -ESRCH; | |
46113830 HW |
1370 | } |
1371 | out_unlock: | |
14d8c9f3 | 1372 | rcu_read_unlock(); |
46113830 HW |
1373 | return ret; |
1374 | } | |
d178bc3a | 1375 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1376 | |
1377 | /* | |
1378 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1379 | * | |
1380 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1381 | * is probably wrong. Should make it like BSD or SYSV. | |
1382 | */ | |
1383 | ||
bc64efd2 | 1384 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1385 | { |
8d42db18 | 1386 | int ret; |
d5df763b PE |
1387 | |
1388 | if (pid > 0) { | |
1389 | rcu_read_lock(); | |
1390 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1391 | rcu_read_unlock(); | |
1392 | return ret; | |
1393 | } | |
1394 | ||
1395 | read_lock(&tasklist_lock); | |
1396 | if (pid != -1) { | |
1397 | ret = __kill_pgrp_info(sig, info, | |
1398 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1399 | } else { | |
1da177e4 LT |
1400 | int retval = 0, count = 0; |
1401 | struct task_struct * p; | |
1402 | ||
1da177e4 | 1403 | for_each_process(p) { |
d25141a8 SB |
1404 | if (task_pid_vnr(p) > 1 && |
1405 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1406 | int err = group_send_sig_info(sig, info, p); |
1407 | ++count; | |
1408 | if (err != -EPERM) | |
1409 | retval = err; | |
1410 | } | |
1411 | } | |
8d42db18 | 1412 | ret = count ? retval : -ESRCH; |
1da177e4 | 1413 | } |
d5df763b PE |
1414 | read_unlock(&tasklist_lock); |
1415 | ||
8d42db18 | 1416 | return ret; |
1da177e4 LT |
1417 | } |
1418 | ||
1419 | /* | |
1420 | * These are for backward compatibility with the rest of the kernel source. | |
1421 | */ | |
1422 | ||
5aba085e | 1423 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1424 | { |
1da177e4 LT |
1425 | /* |
1426 | * Make sure legacy kernel users don't send in bad values | |
1427 | * (normal paths check this in check_kill_permission). | |
1428 | */ | |
7ed20e1a | 1429 | if (!valid_signal(sig)) |
1da177e4 LT |
1430 | return -EINVAL; |
1431 | ||
4a30debf | 1432 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1433 | } |
1434 | ||
b67a1b9e ON |
1435 | #define __si_special(priv) \ |
1436 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1437 | ||
1da177e4 LT |
1438 | int |
1439 | send_sig(int sig, struct task_struct *p, int priv) | |
1440 | { | |
b67a1b9e | 1441 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1442 | } |
1443 | ||
1da177e4 LT |
1444 | void |
1445 | force_sig(int sig, struct task_struct *p) | |
1446 | { | |
b67a1b9e | 1447 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1448 | } |
1449 | ||
1450 | /* | |
1451 | * When things go south during signal handling, we | |
1452 | * will force a SIGSEGV. And if the signal that caused | |
1453 | * the problem was already a SIGSEGV, we'll want to | |
1454 | * make sure we don't even try to deliver the signal.. | |
1455 | */ | |
1456 | int | |
1457 | force_sigsegv(int sig, struct task_struct *p) | |
1458 | { | |
1459 | if (sig == SIGSEGV) { | |
1460 | unsigned long flags; | |
1461 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1462 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1463 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1464 | } | |
1465 | force_sig(SIGSEGV, p); | |
1466 | return 0; | |
1467 | } | |
1468 | ||
c4b92fc1 EB |
1469 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1470 | { | |
146a505d PE |
1471 | int ret; |
1472 | ||
1473 | read_lock(&tasklist_lock); | |
1474 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1475 | read_unlock(&tasklist_lock); | |
1476 | ||
1477 | return ret; | |
c4b92fc1 EB |
1478 | } |
1479 | EXPORT_SYMBOL(kill_pgrp); | |
1480 | ||
1481 | int kill_pid(struct pid *pid, int sig, int priv) | |
1482 | { | |
1483 | return kill_pid_info(sig, __si_special(priv), pid); | |
1484 | } | |
1485 | EXPORT_SYMBOL(kill_pid); | |
1486 | ||
1da177e4 LT |
1487 | /* |
1488 | * These functions support sending signals using preallocated sigqueue | |
1489 | * structures. This is needed "because realtime applications cannot | |
1490 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1491 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1492 | * we allocate the sigqueue structure from the timer_create. If this |
1493 | * allocation fails we are able to report the failure to the application | |
1494 | * with an EAGAIN error. | |
1495 | */ | |
1da177e4 LT |
1496 | struct sigqueue *sigqueue_alloc(void) |
1497 | { | |
f84d49b2 | 1498 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1499 | |
f84d49b2 | 1500 | if (q) |
1da177e4 | 1501 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1502 | |
1503 | return q; | |
1da177e4 LT |
1504 | } |
1505 | ||
1506 | void sigqueue_free(struct sigqueue *q) | |
1507 | { | |
1508 | unsigned long flags; | |
60187d27 ON |
1509 | spinlock_t *lock = ¤t->sighand->siglock; |
1510 | ||
1da177e4 LT |
1511 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1512 | /* | |
c8e85b4f ON |
1513 | * We must hold ->siglock while testing q->list |
1514 | * to serialize with collect_signal() or with | |
da7978b0 | 1515 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1516 | */ |
60187d27 | 1517 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1518 | q->flags &= ~SIGQUEUE_PREALLOC; |
1519 | /* | |
1520 | * If it is queued it will be freed when dequeued, | |
1521 | * like the "regular" sigqueue. | |
1522 | */ | |
60187d27 | 1523 | if (!list_empty(&q->list)) |
c8e85b4f | 1524 | q = NULL; |
60187d27 ON |
1525 | spin_unlock_irqrestore(lock, flags); |
1526 | ||
c8e85b4f ON |
1527 | if (q) |
1528 | __sigqueue_free(q); | |
1da177e4 LT |
1529 | } |
1530 | ||
ac5c2153 | 1531 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1532 | { |
e62e6650 | 1533 | int sig = q->info.si_signo; |
2ca3515a | 1534 | struct sigpending *pending; |
e62e6650 | 1535 | unsigned long flags; |
163566f6 | 1536 | int ret, result; |
2ca3515a | 1537 | |
4cd4b6d4 | 1538 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1539 | |
1540 | ret = -1; | |
1541 | if (!likely(lock_task_sighand(t, &flags))) | |
1542 | goto ret; | |
1543 | ||
7e695a5e | 1544 | ret = 1; /* the signal is ignored */ |
163566f6 | 1545 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1546 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1547 | goto out; |
1548 | ||
1549 | ret = 0; | |
9e3bd6c3 PE |
1550 | if (unlikely(!list_empty(&q->list))) { |
1551 | /* | |
1552 | * If an SI_TIMER entry is already queue just increment | |
1553 | * the overrun count. | |
1554 | */ | |
9e3bd6c3 PE |
1555 | BUG_ON(q->info.si_code != SI_TIMER); |
1556 | q->info.si_overrun++; | |
163566f6 | 1557 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1558 | goto out; |
9e3bd6c3 | 1559 | } |
ba661292 | 1560 | q->info.si_overrun = 0; |
9e3bd6c3 | 1561 | |
9e3bd6c3 | 1562 | signalfd_notify(t, sig); |
2ca3515a | 1563 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1564 | list_add_tail(&q->list, &pending->list); |
1565 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1566 | complete_signal(sig, t, group); |
163566f6 | 1567 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1568 | out: |
163566f6 | 1569 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1570 | unlock_task_sighand(t, &flags); |
1571 | ret: | |
1572 | return ret; | |
9e3bd6c3 PE |
1573 | } |
1574 | ||
1da177e4 LT |
1575 | /* |
1576 | * Let a parent know about the death of a child. | |
1577 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1578 | * |
53c8f9f1 ON |
1579 | * Returns true if our parent ignored us and so we've switched to |
1580 | * self-reaping. | |
1da177e4 | 1581 | */ |
53c8f9f1 | 1582 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1583 | { |
1584 | struct siginfo info; | |
1585 | unsigned long flags; | |
1586 | struct sighand_struct *psig; | |
53c8f9f1 | 1587 | bool autoreap = false; |
bde8285e | 1588 | u64 utime, stime; |
1da177e4 LT |
1589 | |
1590 | BUG_ON(sig == -1); | |
1591 | ||
1592 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1593 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1594 | |
d21142ec | 1595 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1596 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1597 | ||
b6e238dc ON |
1598 | if (sig != SIGCHLD) { |
1599 | /* | |
1600 | * This is only possible if parent == real_parent. | |
1601 | * Check if it has changed security domain. | |
1602 | */ | |
1603 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1604 | sig = SIGCHLD; | |
1605 | } | |
1606 | ||
1da177e4 LT |
1607 | info.si_signo = sig; |
1608 | info.si_errno = 0; | |
b488893a | 1609 | /* |
32084504 EB |
1610 | * We are under tasklist_lock here so our parent is tied to |
1611 | * us and cannot change. | |
b488893a | 1612 | * |
32084504 EB |
1613 | * task_active_pid_ns will always return the same pid namespace |
1614 | * until a task passes through release_task. | |
b488893a PE |
1615 | * |
1616 | * write_lock() currently calls preempt_disable() which is the | |
1617 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1618 | * correct to rely on this | |
1619 | */ | |
1620 | rcu_read_lock(); | |
32084504 | 1621 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1622 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1623 | task_uid(tsk)); | |
b488893a PE |
1624 | rcu_read_unlock(); |
1625 | ||
bde8285e FW |
1626 | task_cputime(tsk, &utime, &stime); |
1627 | info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); | |
1628 | info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1629 | |
1630 | info.si_status = tsk->exit_code & 0x7f; | |
1631 | if (tsk->exit_code & 0x80) | |
1632 | info.si_code = CLD_DUMPED; | |
1633 | else if (tsk->exit_code & 0x7f) | |
1634 | info.si_code = CLD_KILLED; | |
1635 | else { | |
1636 | info.si_code = CLD_EXITED; | |
1637 | info.si_status = tsk->exit_code >> 8; | |
1638 | } | |
1639 | ||
1640 | psig = tsk->parent->sighand; | |
1641 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1642 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1643 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1644 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1645 | /* | |
1646 | * We are exiting and our parent doesn't care. POSIX.1 | |
1647 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1648 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1649 | * automatically and not left for our parent's wait4 call. | |
1650 | * Rather than having the parent do it as a magic kind of | |
1651 | * signal handler, we just set this to tell do_exit that we | |
1652 | * can be cleaned up without becoming a zombie. Note that | |
1653 | * we still call __wake_up_parent in this case, because a | |
1654 | * blocked sys_wait4 might now return -ECHILD. | |
1655 | * | |
1656 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1657 | * is implementation-defined: we do (if you don't want | |
1658 | * it, just use SIG_IGN instead). | |
1659 | */ | |
53c8f9f1 | 1660 | autoreap = true; |
1da177e4 | 1661 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1662 | sig = 0; |
1da177e4 | 1663 | } |
53c8f9f1 | 1664 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1665 | __group_send_sig_info(sig, &info, tsk->parent); |
1666 | __wake_up_parent(tsk, tsk->parent); | |
1667 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1668 | |
53c8f9f1 | 1669 | return autoreap; |
1da177e4 LT |
1670 | } |
1671 | ||
75b95953 TH |
1672 | /** |
1673 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1674 | * @tsk: task reporting the state change | |
1675 | * @for_ptracer: the notification is for ptracer | |
1676 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1677 | * | |
1678 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1679 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1680 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1681 | * | |
1682 | * CONTEXT: | |
1683 | * Must be called with tasklist_lock at least read locked. | |
1684 | */ | |
1685 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1686 | bool for_ptracer, int why) | |
1da177e4 LT |
1687 | { |
1688 | struct siginfo info; | |
1689 | unsigned long flags; | |
bc505a47 | 1690 | struct task_struct *parent; |
1da177e4 | 1691 | struct sighand_struct *sighand; |
bde8285e | 1692 | u64 utime, stime; |
1da177e4 | 1693 | |
75b95953 | 1694 | if (for_ptracer) { |
bc505a47 | 1695 | parent = tsk->parent; |
75b95953 | 1696 | } else { |
bc505a47 ON |
1697 | tsk = tsk->group_leader; |
1698 | parent = tsk->real_parent; | |
1699 | } | |
1700 | ||
1da177e4 LT |
1701 | info.si_signo = SIGCHLD; |
1702 | info.si_errno = 0; | |
b488893a | 1703 | /* |
5aba085e | 1704 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1705 | */ |
1706 | rcu_read_lock(); | |
17cf22c3 | 1707 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1708 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1709 | rcu_read_unlock(); |
1710 | ||
bde8285e FW |
1711 | task_cputime(tsk, &utime, &stime); |
1712 | info.si_utime = nsec_to_clock_t(utime); | |
1713 | info.si_stime = nsec_to_clock_t(stime); | |
1da177e4 LT |
1714 | |
1715 | info.si_code = why; | |
1716 | switch (why) { | |
1717 | case CLD_CONTINUED: | |
1718 | info.si_status = SIGCONT; | |
1719 | break; | |
1720 | case CLD_STOPPED: | |
1721 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1722 | break; | |
1723 | case CLD_TRAPPED: | |
1724 | info.si_status = tsk->exit_code & 0x7f; | |
1725 | break; | |
1726 | default: | |
1727 | BUG(); | |
1728 | } | |
1729 | ||
1730 | sighand = parent->sighand; | |
1731 | spin_lock_irqsave(&sighand->siglock, flags); | |
1732 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1733 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1734 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1735 | /* | |
1736 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1737 | */ | |
1738 | __wake_up_parent(tsk, parent); | |
1739 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1740 | } | |
1741 | ||
d5f70c00 ON |
1742 | static inline int may_ptrace_stop(void) |
1743 | { | |
d21142ec | 1744 | if (!likely(current->ptrace)) |
d5f70c00 | 1745 | return 0; |
d5f70c00 ON |
1746 | /* |
1747 | * Are we in the middle of do_coredump? | |
1748 | * If so and our tracer is also part of the coredump stopping | |
1749 | * is a deadlock situation, and pointless because our tracer | |
1750 | * is dead so don't allow us to stop. | |
1751 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1752 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1753 | * is safe to enter schedule(). |
9899d11f ON |
1754 | * |
1755 | * This is almost outdated, a task with the pending SIGKILL can't | |
1756 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1757 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1758 | */ |
999d9fc1 | 1759 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1760 | unlikely(current->mm == current->parent->mm)) |
1761 | return 0; | |
1762 | ||
1763 | return 1; | |
1764 | } | |
1765 | ||
1a669c2f | 1766 | /* |
5aba085e | 1767 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1768 | * Called with the siglock held. |
1769 | */ | |
1770 | static int sigkill_pending(struct task_struct *tsk) | |
1771 | { | |
3d749b9e ON |
1772 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1773 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1774 | } |
1775 | ||
1da177e4 LT |
1776 | /* |
1777 | * This must be called with current->sighand->siglock held. | |
1778 | * | |
1779 | * This should be the path for all ptrace stops. | |
1780 | * We always set current->last_siginfo while stopped here. | |
1781 | * That makes it a way to test a stopped process for | |
1782 | * being ptrace-stopped vs being job-control-stopped. | |
1783 | * | |
20686a30 ON |
1784 | * If we actually decide not to stop at all because the tracer |
1785 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1786 | */ |
fe1bc6a0 | 1787 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1788 | __releases(¤t->sighand->siglock) |
1789 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1790 | { |
ceb6bd67 TH |
1791 | bool gstop_done = false; |
1792 | ||
1a669c2f RM |
1793 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1794 | /* | |
1795 | * The arch code has something special to do before a | |
1796 | * ptrace stop. This is allowed to block, e.g. for faults | |
1797 | * on user stack pages. We can't keep the siglock while | |
1798 | * calling arch_ptrace_stop, so we must release it now. | |
1799 | * To preserve proper semantics, we must do this before | |
1800 | * any signal bookkeeping like checking group_stop_count. | |
1801 | * Meanwhile, a SIGKILL could come in before we retake the | |
1802 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1803 | * So after regaining the lock, we must check for SIGKILL. | |
1804 | */ | |
1805 | spin_unlock_irq(¤t->sighand->siglock); | |
1806 | arch_ptrace_stop(exit_code, info); | |
1807 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1808 | if (sigkill_pending(current)) |
1809 | return; | |
1a669c2f RM |
1810 | } |
1811 | ||
1da177e4 | 1812 | /* |
81be24b8 TH |
1813 | * We're committing to trapping. TRACED should be visible before |
1814 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1815 | * Also, transition to TRACED and updates to ->jobctl should be | |
1816 | * atomic with respect to siglock and should be done after the arch | |
1817 | * hook as siglock is released and regrabbed across it. | |
1da177e4 | 1818 | */ |
81be24b8 | 1819 | set_current_state(TASK_TRACED); |
1da177e4 LT |
1820 | |
1821 | current->last_siginfo = info; | |
1822 | current->exit_code = exit_code; | |
1823 | ||
d79fdd6d | 1824 | /* |
0ae8ce1c TH |
1825 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1826 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1827 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1828 | * could be clear now. We act as if SIGCONT is received after | |
1829 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1830 | */ |
a8f072c1 | 1831 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1832 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1833 | |
fb1d910c | 1834 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1835 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1836 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1837 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1838 | |
81be24b8 | 1839 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1840 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1841 | |
1da177e4 LT |
1842 | spin_unlock_irq(¤t->sighand->siglock); |
1843 | read_lock(&tasklist_lock); | |
3d749b9e | 1844 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1845 | /* |
1846 | * Notify parents of the stop. | |
1847 | * | |
1848 | * While ptraced, there are two parents - the ptracer and | |
1849 | * the real_parent of the group_leader. The ptracer should | |
1850 | * know about every stop while the real parent is only | |
1851 | * interested in the completion of group stop. The states | |
1852 | * for the two don't interact with each other. Notify | |
1853 | * separately unless they're gonna be duplicates. | |
1854 | */ | |
1855 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1856 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1857 | do_notify_parent_cldstop(current, false, why); |
1858 | ||
53da1d94 MS |
1859 | /* |
1860 | * Don't want to allow preemption here, because | |
1861 | * sys_ptrace() needs this task to be inactive. | |
1862 | * | |
1863 | * XXX: implement read_unlock_no_resched(). | |
1864 | */ | |
1865 | preempt_disable(); | |
1da177e4 | 1866 | read_unlock(&tasklist_lock); |
53da1d94 | 1867 | preempt_enable_no_resched(); |
5d8f72b5 | 1868 | freezable_schedule(); |
1da177e4 LT |
1869 | } else { |
1870 | /* | |
1871 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1872 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1873 | * |
1874 | * If @gstop_done, the ptracer went away between group stop | |
1875 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1876 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1877 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1878 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1879 | */ |
ceb6bd67 TH |
1880 | if (gstop_done) |
1881 | do_notify_parent_cldstop(current, false, why); | |
1882 | ||
9899d11f | 1883 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 1884 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1885 | if (clear_code) |
1886 | current->exit_code = 0; | |
6405f7f4 | 1887 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1888 | } |
1889 | ||
1890 | /* | |
1891 | * We are back. Now reacquire the siglock before touching | |
1892 | * last_siginfo, so that we are sure to have synchronized with | |
1893 | * any signal-sending on another CPU that wants to examine it. | |
1894 | */ | |
1895 | spin_lock_irq(¤t->sighand->siglock); | |
1896 | current->last_siginfo = NULL; | |
1897 | ||
544b2c91 TH |
1898 | /* LISTENING can be set only during STOP traps, clear it */ |
1899 | current->jobctl &= ~JOBCTL_LISTENING; | |
1900 | ||
1da177e4 LT |
1901 | /* |
1902 | * Queued signals ignored us while we were stopped for tracing. | |
1903 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1904 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1905 | */ |
b74d0deb | 1906 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1907 | } |
1908 | ||
3544d72a | 1909 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1910 | { |
1911 | siginfo_t info; | |
1912 | ||
1da177e4 | 1913 | memset(&info, 0, sizeof info); |
3544d72a | 1914 | info.si_signo = signr; |
1da177e4 | 1915 | info.si_code = exit_code; |
b488893a | 1916 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1917 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1918 | |
1919 | /* Let the debugger run. */ | |
3544d72a TH |
1920 | ptrace_stop(exit_code, why, 1, &info); |
1921 | } | |
1922 | ||
1923 | void ptrace_notify(int exit_code) | |
1924 | { | |
1925 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
1926 | if (unlikely(current->task_works)) |
1927 | task_work_run(); | |
3544d72a | 1928 | |
1da177e4 | 1929 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1930 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1931 | spin_unlock_irq(¤t->sighand->siglock); |
1932 | } | |
1933 | ||
73ddff2b TH |
1934 | /** |
1935 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1936 | * @signr: signr causing group stop if initiating | |
1937 | * | |
1938 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1939 | * and participate in it. If already set, participate in the existing | |
1940 | * group stop. If participated in a group stop (and thus slept), %true is | |
1941 | * returned with siglock released. | |
1942 | * | |
1943 | * If ptraced, this function doesn't handle stop itself. Instead, | |
1944 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
1945 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
1946 | * places afterwards. | |
1947 | * | |
1948 | * CONTEXT: | |
1949 | * Must be called with @current->sighand->siglock held, which is released | |
1950 | * on %true return. | |
1951 | * | |
1952 | * RETURNS: | |
1953 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
1954 | * %true if participated in group stop. | |
1da177e4 | 1955 | */ |
73ddff2b TH |
1956 | static bool do_signal_stop(int signr) |
1957 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
1958 | { |
1959 | struct signal_struct *sig = current->signal; | |
1da177e4 | 1960 | |
a8f072c1 | 1961 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
b76808e6 | 1962 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
f558b7e4 ON |
1963 | struct task_struct *t; |
1964 | ||
a8f072c1 TH |
1965 | /* signr will be recorded in task->jobctl for retries */ |
1966 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 1967 | |
a8f072c1 | 1968 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 1969 | unlikely(signal_group_exit(sig))) |
73ddff2b | 1970 | return false; |
1da177e4 | 1971 | /* |
408a37de TH |
1972 | * There is no group stop already in progress. We must |
1973 | * initiate one now. | |
1974 | * | |
1975 | * While ptraced, a task may be resumed while group stop is | |
1976 | * still in effect and then receive a stop signal and | |
1977 | * initiate another group stop. This deviates from the | |
1978 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
1979 | * cause two group stops when !ptraced. That is why we |
1980 | * also check !task_is_stopped(t) below. | |
408a37de TH |
1981 | * |
1982 | * The condition can be distinguished by testing whether | |
1983 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
1984 | * group_exit_code in such case. | |
1985 | * | |
1986 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
1987 | * an intervening stop signal is required to cause two | |
1988 | * continued events regardless of ptrace. | |
1da177e4 | 1989 | */ |
408a37de TH |
1990 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
1991 | sig->group_exit_code = signr; | |
1da177e4 | 1992 | |
7dd3db54 TH |
1993 | sig->group_stop_count = 0; |
1994 | ||
1995 | if (task_set_jobctl_pending(current, signr | gstop)) | |
1996 | sig->group_stop_count++; | |
1da177e4 | 1997 | |
8d38f203 ON |
1998 | t = current; |
1999 | while_each_thread(current, t) { | |
1da177e4 | 2000 | /* |
a122b341 ON |
2001 | * Setting state to TASK_STOPPED for a group |
2002 | * stop is always done with the siglock held, | |
2003 | * so this check has no races. | |
1da177e4 | 2004 | */ |
7dd3db54 TH |
2005 | if (!task_is_stopped(t) && |
2006 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2007 | sig->group_stop_count++; |
fb1d910c TH |
2008 | if (likely(!(t->ptrace & PT_SEIZED))) |
2009 | signal_wake_up(t, 0); | |
2010 | else | |
2011 | ptrace_trap_notify(t); | |
a122b341 | 2012 | } |
d79fdd6d | 2013 | } |
1da177e4 | 2014 | } |
73ddff2b | 2015 | |
d21142ec | 2016 | if (likely(!current->ptrace)) { |
5224fa36 | 2017 | int notify = 0; |
1da177e4 | 2018 | |
5224fa36 TH |
2019 | /* |
2020 | * If there are no other threads in the group, or if there | |
2021 | * is a group stop in progress and we are the last to stop, | |
2022 | * report to the parent. | |
2023 | */ | |
2024 | if (task_participate_group_stop(current)) | |
2025 | notify = CLD_STOPPED; | |
2026 | ||
ae6d2ed7 | 2027 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
2028 | spin_unlock_irq(¤t->sighand->siglock); |
2029 | ||
62bcf9d9 TH |
2030 | /* |
2031 | * Notify the parent of the group stop completion. Because | |
2032 | * we're not holding either the siglock or tasklist_lock | |
2033 | * here, ptracer may attach inbetween; however, this is for | |
2034 | * group stop and should always be delivered to the real | |
2035 | * parent of the group leader. The new ptracer will get | |
2036 | * its notification when this task transitions into | |
2037 | * TASK_TRACED. | |
2038 | */ | |
5224fa36 TH |
2039 | if (notify) { |
2040 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2041 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2042 | read_unlock(&tasklist_lock); |
2043 | } | |
2044 | ||
2045 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
5d8f72b5 | 2046 | freezable_schedule(); |
73ddff2b | 2047 | return true; |
d79fdd6d | 2048 | } else { |
73ddff2b TH |
2049 | /* |
2050 | * While ptraced, group stop is handled by STOP trap. | |
2051 | * Schedule it and let the caller deal with it. | |
2052 | */ | |
2053 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2054 | return false; | |
ae6d2ed7 | 2055 | } |
73ddff2b | 2056 | } |
1da177e4 | 2057 | |
73ddff2b TH |
2058 | /** |
2059 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2060 | * | |
3544d72a TH |
2061 | * When PT_SEIZED, it's used for both group stop and explicit |
2062 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2063 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2064 | * the stop signal; otherwise, %SIGTRAP. | |
2065 | * | |
2066 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2067 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2068 | * |
2069 | * CONTEXT: | |
2070 | * Must be called with @current->sighand->siglock held, which may be | |
2071 | * released and re-acquired before returning with intervening sleep. | |
2072 | */ | |
2073 | static void do_jobctl_trap(void) | |
2074 | { | |
3544d72a | 2075 | struct signal_struct *signal = current->signal; |
73ddff2b | 2076 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2077 | |
3544d72a TH |
2078 | if (current->ptrace & PT_SEIZED) { |
2079 | if (!signal->group_stop_count && | |
2080 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2081 | signr = SIGTRAP; | |
2082 | WARN_ON_ONCE(!signr); | |
2083 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2084 | CLD_STOPPED); | |
2085 | } else { | |
2086 | WARN_ON_ONCE(!signr); | |
2087 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2088 | current->exit_code = 0; | |
ae6d2ed7 | 2089 | } |
1da177e4 LT |
2090 | } |
2091 | ||
94eb22d5 | 2092 | static int ptrace_signal(int signr, siginfo_t *info) |
18c98b65 | 2093 | { |
b7f9591c | 2094 | ptrace_signal_deliver(); |
8a352418 ON |
2095 | /* |
2096 | * We do not check sig_kernel_stop(signr) but set this marker | |
2097 | * unconditionally because we do not know whether debugger will | |
2098 | * change signr. This flag has no meaning unless we are going | |
2099 | * to stop after return from ptrace_stop(). In this case it will | |
2100 | * be checked in do_signal_stop(), we should only stop if it was | |
2101 | * not cleared by SIGCONT while we were sleeping. See also the | |
2102 | * comment in dequeue_signal(). | |
2103 | */ | |
2104 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2105 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2106 | |
2107 | /* We're back. Did the debugger cancel the sig? */ | |
2108 | signr = current->exit_code; | |
2109 | if (signr == 0) | |
2110 | return signr; | |
2111 | ||
2112 | current->exit_code = 0; | |
2113 | ||
5aba085e RD |
2114 | /* |
2115 | * Update the siginfo structure if the signal has | |
2116 | * changed. If the debugger wanted something | |
2117 | * specific in the siginfo structure then it should | |
2118 | * have updated *info via PTRACE_SETSIGINFO. | |
2119 | */ | |
18c98b65 RM |
2120 | if (signr != info->si_signo) { |
2121 | info->si_signo = signr; | |
2122 | info->si_errno = 0; | |
2123 | info->si_code = SI_USER; | |
6b550f94 | 2124 | rcu_read_lock(); |
18c98b65 | 2125 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2126 | info->si_uid = from_kuid_munged(current_user_ns(), |
2127 | task_uid(current->parent)); | |
6b550f94 | 2128 | rcu_read_unlock(); |
18c98b65 RM |
2129 | } |
2130 | ||
2131 | /* If the (new) signal is now blocked, requeue it. */ | |
2132 | if (sigismember(¤t->blocked, signr)) { | |
2133 | specific_send_sig_info(signr, info, current); | |
2134 | signr = 0; | |
2135 | } | |
2136 | ||
2137 | return signr; | |
2138 | } | |
2139 | ||
828b1f65 | 2140 | int get_signal(struct ksignal *ksig) |
1da177e4 | 2141 | { |
f6b76d4f ON |
2142 | struct sighand_struct *sighand = current->sighand; |
2143 | struct signal_struct *signal = current->signal; | |
2144 | int signr; | |
1da177e4 | 2145 | |
f784e8a7 ON |
2146 | if (unlikely(current->task_works)) |
2147 | task_work_run(); | |
72667028 | 2148 | |
0326f5a9 SD |
2149 | if (unlikely(uprobe_deny_signal())) |
2150 | return 0; | |
2151 | ||
13b1c3d4 | 2152 | /* |
5d8f72b5 ON |
2153 | * Do this once, we can't return to user-mode if freezing() == T. |
2154 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2155 | * thus do not need another check after return. | |
13b1c3d4 | 2156 | */ |
fc558a74 RW |
2157 | try_to_freeze(); |
2158 | ||
5d8f72b5 | 2159 | relock: |
f6b76d4f | 2160 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2161 | /* |
2162 | * Every stopped thread goes here after wakeup. Check to see if | |
2163 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2164 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2165 | */ | |
f6b76d4f | 2166 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2167 | int why; |
2168 | ||
2169 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2170 | why = CLD_CONTINUED; | |
2171 | else | |
2172 | why = CLD_STOPPED; | |
2173 | ||
f6b76d4f | 2174 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2175 | |
ae6d2ed7 | 2176 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2177 | |
ceb6bd67 TH |
2178 | /* |
2179 | * Notify the parent that we're continuing. This event is | |
2180 | * always per-process and doesn't make whole lot of sense | |
2181 | * for ptracers, who shouldn't consume the state via | |
2182 | * wait(2) either, but, for backward compatibility, notify | |
2183 | * the ptracer of the group leader too unless it's gonna be | |
2184 | * a duplicate. | |
2185 | */ | |
edf2ed15 | 2186 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2187 | do_notify_parent_cldstop(current, false, why); |
2188 | ||
bb3696da ON |
2189 | if (ptrace_reparented(current->group_leader)) |
2190 | do_notify_parent_cldstop(current->group_leader, | |
2191 | true, why); | |
edf2ed15 | 2192 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2193 | |
e4420551 ON |
2194 | goto relock; |
2195 | } | |
2196 | ||
1da177e4 LT |
2197 | for (;;) { |
2198 | struct k_sigaction *ka; | |
1be53963 | 2199 | |
dd1d6772 TH |
2200 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2201 | do_signal_stop(0)) | |
7bcf6a2c | 2202 | goto relock; |
1be53963 | 2203 | |
73ddff2b TH |
2204 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2205 | do_jobctl_trap(); | |
2206 | spin_unlock_irq(&sighand->siglock); | |
2207 | goto relock; | |
2208 | } | |
1da177e4 | 2209 | |
828b1f65 | 2210 | signr = dequeue_signal(current, ¤t->blocked, &ksig->info); |
7bcf6a2c | 2211 | |
dd1d6772 TH |
2212 | if (!signr) |
2213 | break; /* will return 0 */ | |
7bcf6a2c | 2214 | |
8a352418 | 2215 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
828b1f65 | 2216 | signr = ptrace_signal(signr, &ksig->info); |
dd1d6772 TH |
2217 | if (!signr) |
2218 | continue; | |
1da177e4 LT |
2219 | } |
2220 | ||
dd1d6772 TH |
2221 | ka = &sighand->action[signr-1]; |
2222 | ||
f9d4257e | 2223 | /* Trace actually delivered signals. */ |
828b1f65 | 2224 | trace_signal_deliver(signr, &ksig->info, ka); |
f9d4257e | 2225 | |
1da177e4 LT |
2226 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2227 | continue; | |
2228 | if (ka->sa.sa_handler != SIG_DFL) { | |
2229 | /* Run the handler. */ | |
828b1f65 | 2230 | ksig->ka = *ka; |
1da177e4 LT |
2231 | |
2232 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2233 | ka->sa.sa_handler = SIG_DFL; | |
2234 | ||
2235 | break; /* will return non-zero "signr" value */ | |
2236 | } | |
2237 | ||
2238 | /* | |
2239 | * Now we are doing the default action for this signal. | |
2240 | */ | |
2241 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2242 | continue; | |
2243 | ||
84d73786 | 2244 | /* |
0fbc26a6 | 2245 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2246 | * Container-init gets no signals it doesn't want from same |
2247 | * container. | |
2248 | * | |
2249 | * Note that if global/container-init sees a sig_kernel_only() | |
2250 | * signal here, the signal must have been generated internally | |
2251 | * or must have come from an ancestor namespace. In either | |
2252 | * case, the signal cannot be dropped. | |
84d73786 | 2253 | */ |
fae5fa44 | 2254 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2255 | !sig_kernel_only(signr)) |
1da177e4 LT |
2256 | continue; |
2257 | ||
2258 | if (sig_kernel_stop(signr)) { | |
2259 | /* | |
2260 | * The default action is to stop all threads in | |
2261 | * the thread group. The job control signals | |
2262 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2263 | * always works. Note that siglock needs to be | |
2264 | * dropped during the call to is_orphaned_pgrp() | |
2265 | * because of lock ordering with tasklist_lock. | |
2266 | * This allows an intervening SIGCONT to be posted. | |
2267 | * We need to check for that and bail out if necessary. | |
2268 | */ | |
2269 | if (signr != SIGSTOP) { | |
f6b76d4f | 2270 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2271 | |
2272 | /* signals can be posted during this window */ | |
2273 | ||
3e7cd6c4 | 2274 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2275 | goto relock; |
2276 | ||
f6b76d4f | 2277 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2278 | } |
2279 | ||
828b1f65 | 2280 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
1da177e4 LT |
2281 | /* It released the siglock. */ |
2282 | goto relock; | |
2283 | } | |
2284 | ||
2285 | /* | |
2286 | * We didn't actually stop, due to a race | |
2287 | * with SIGCONT or something like that. | |
2288 | */ | |
2289 | continue; | |
2290 | } | |
2291 | ||
f6b76d4f | 2292 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2293 | |
2294 | /* | |
2295 | * Anything else is fatal, maybe with a core dump. | |
2296 | */ | |
2297 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2298 | |
1da177e4 | 2299 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2300 | if (print_fatal_signals) |
828b1f65 | 2301 | print_fatal_signal(ksig->info.si_signo); |
2b5faa4c | 2302 | proc_coredump_connector(current); |
1da177e4 LT |
2303 | /* |
2304 | * If it was able to dump core, this kills all | |
2305 | * other threads in the group and synchronizes with | |
2306 | * their demise. If we lost the race with another | |
2307 | * thread getting here, it set group_exit_code | |
2308 | * first and our do_group_exit call below will use | |
2309 | * that value and ignore the one we pass it. | |
2310 | */ | |
828b1f65 | 2311 | do_coredump(&ksig->info); |
1da177e4 LT |
2312 | } |
2313 | ||
2314 | /* | |
2315 | * Death signals, no core dump. | |
2316 | */ | |
828b1f65 | 2317 | do_group_exit(ksig->info.si_signo); |
1da177e4 LT |
2318 | /* NOTREACHED */ |
2319 | } | |
f6b76d4f | 2320 | spin_unlock_irq(&sighand->siglock); |
828b1f65 RW |
2321 | |
2322 | ksig->sig = signr; | |
2323 | return ksig->sig > 0; | |
1da177e4 LT |
2324 | } |
2325 | ||
5e6292c0 | 2326 | /** |
efee984c | 2327 | * signal_delivered - |
10b1c7ac | 2328 | * @ksig: kernel signal struct |
efee984c | 2329 | * @stepping: nonzero if debugger single-step or block-step in use |
5e6292c0 | 2330 | * |
e227867f | 2331 | * This function should be called when a signal has successfully been |
10b1c7ac | 2332 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
efee984c | 2333 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER |
10b1c7ac | 2334 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
5e6292c0 | 2335 | */ |
10b1c7ac | 2336 | static void signal_delivered(struct ksignal *ksig, int stepping) |
5e6292c0 MF |
2337 | { |
2338 | sigset_t blocked; | |
2339 | ||
a610d6e6 AV |
2340 | /* A signal was successfully delivered, and the |
2341 | saved sigmask was stored on the signal frame, | |
2342 | and will be restored by sigreturn. So we can | |
2343 | simply clear the restore sigmask flag. */ | |
2344 | clear_restore_sigmask(); | |
2345 | ||
10b1c7ac RW |
2346 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
2347 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) | |
2348 | sigaddset(&blocked, ksig->sig); | |
5e6292c0 | 2349 | set_current_blocked(&blocked); |
df5601f9 | 2350 | tracehook_signal_handler(stepping); |
5e6292c0 MF |
2351 | } |
2352 | ||
2ce5da17 AV |
2353 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2354 | { | |
2355 | if (failed) | |
2356 | force_sigsegv(ksig->sig, current); | |
2357 | else | |
10b1c7ac | 2358 | signal_delivered(ksig, stepping); |
2ce5da17 AV |
2359 | } |
2360 | ||
0edceb7b ON |
2361 | /* |
2362 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2363 | * group-wide signal. Other threads should be notified now to take |
2364 | * the shared signals in @which since we will not. | |
0edceb7b | 2365 | */ |
f646e227 | 2366 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2367 | { |
f646e227 | 2368 | sigset_t retarget; |
0edceb7b ON |
2369 | struct task_struct *t; |
2370 | ||
f646e227 ON |
2371 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2372 | if (sigisemptyset(&retarget)) | |
2373 | return; | |
2374 | ||
0edceb7b ON |
2375 | t = tsk; |
2376 | while_each_thread(tsk, t) { | |
fec9993d ON |
2377 | if (t->flags & PF_EXITING) |
2378 | continue; | |
2379 | ||
2380 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2381 | continue; | |
2382 | /* Remove the signals this thread can handle. */ | |
2383 | sigandsets(&retarget, &retarget, &t->blocked); | |
2384 | ||
2385 | if (!signal_pending(t)) | |
2386 | signal_wake_up(t, 0); | |
2387 | ||
2388 | if (sigisemptyset(&retarget)) | |
2389 | break; | |
0edceb7b ON |
2390 | } |
2391 | } | |
2392 | ||
d12619b5 ON |
2393 | void exit_signals(struct task_struct *tsk) |
2394 | { | |
2395 | int group_stop = 0; | |
f646e227 | 2396 | sigset_t unblocked; |
d12619b5 | 2397 | |
77e4ef99 TH |
2398 | /* |
2399 | * @tsk is about to have PF_EXITING set - lock out users which | |
2400 | * expect stable threadgroup. | |
2401 | */ | |
780de9dd | 2402 | cgroup_threadgroup_change_begin(tsk); |
77e4ef99 | 2403 | |
5dee1707 ON |
2404 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2405 | tsk->flags |= PF_EXITING; | |
780de9dd | 2406 | cgroup_threadgroup_change_end(tsk); |
5dee1707 | 2407 | return; |
d12619b5 ON |
2408 | } |
2409 | ||
5dee1707 | 2410 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2411 | /* |
2412 | * From now this task is not visible for group-wide signals, | |
2413 | * see wants_signal(), do_signal_stop(). | |
2414 | */ | |
2415 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2416 | |
780de9dd | 2417 | cgroup_threadgroup_change_end(tsk); |
77e4ef99 | 2418 | |
5dee1707 ON |
2419 | if (!signal_pending(tsk)) |
2420 | goto out; | |
2421 | ||
f646e227 ON |
2422 | unblocked = tsk->blocked; |
2423 | signotset(&unblocked); | |
2424 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2425 | |
a8f072c1 | 2426 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2427 | task_participate_group_stop(tsk)) |
edf2ed15 | 2428 | group_stop = CLD_STOPPED; |
5dee1707 | 2429 | out: |
d12619b5 ON |
2430 | spin_unlock_irq(&tsk->sighand->siglock); |
2431 | ||
62bcf9d9 TH |
2432 | /* |
2433 | * If group stop has completed, deliver the notification. This | |
2434 | * should always go to the real parent of the group leader. | |
2435 | */ | |
ae6d2ed7 | 2436 | if (unlikely(group_stop)) { |
d12619b5 | 2437 | read_lock(&tasklist_lock); |
62bcf9d9 | 2438 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2439 | read_unlock(&tasklist_lock); |
2440 | } | |
2441 | } | |
2442 | ||
1da177e4 LT |
2443 | EXPORT_SYMBOL(recalc_sigpending); |
2444 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2445 | EXPORT_SYMBOL(flush_signals); | |
2446 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2447 | EXPORT_SYMBOL(send_sig); |
2448 | EXPORT_SYMBOL(send_sig_info); | |
2449 | EXPORT_SYMBOL(sigprocmask); | |
1da177e4 LT |
2450 | |
2451 | /* | |
2452 | * System call entry points. | |
2453 | */ | |
2454 | ||
41c57892 RD |
2455 | /** |
2456 | * sys_restart_syscall - restart a system call | |
2457 | */ | |
754fe8d2 | 2458 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 | 2459 | { |
f56141e3 | 2460 | struct restart_block *restart = ¤t->restart_block; |
1da177e4 LT |
2461 | return restart->fn(restart); |
2462 | } | |
2463 | ||
2464 | long do_no_restart_syscall(struct restart_block *param) | |
2465 | { | |
2466 | return -EINTR; | |
2467 | } | |
2468 | ||
b182801a ON |
2469 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2470 | { | |
2471 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2472 | sigset_t newblocked; | |
2473 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2474 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2475 | retarget_shared_pending(tsk, &newblocked); |
2476 | } | |
2477 | tsk->blocked = *newset; | |
2478 | recalc_sigpending(); | |
2479 | } | |
2480 | ||
e6fa16ab ON |
2481 | /** |
2482 | * set_current_blocked - change current->blocked mask | |
2483 | * @newset: new mask | |
2484 | * | |
2485 | * It is wrong to change ->blocked directly, this helper should be used | |
2486 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2487 | */ |
77097ae5 AV |
2488 | void set_current_blocked(sigset_t *newset) |
2489 | { | |
77097ae5 | 2490 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2491 | __set_current_blocked(newset); |
77097ae5 AV |
2492 | } |
2493 | ||
2494 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2495 | { |
2496 | struct task_struct *tsk = current; | |
2497 | ||
c7be96af WL |
2498 | /* |
2499 | * In case the signal mask hasn't changed, there is nothing we need | |
2500 | * to do. The current->blocked shouldn't be modified by other task. | |
2501 | */ | |
2502 | if (sigequalsets(&tsk->blocked, newset)) | |
2503 | return; | |
2504 | ||
e6fa16ab | 2505 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2506 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2507 | spin_unlock_irq(&tsk->sighand->siglock); |
2508 | } | |
1da177e4 LT |
2509 | |
2510 | /* | |
2511 | * This is also useful for kernel threads that want to temporarily | |
2512 | * (or permanently) block certain signals. | |
2513 | * | |
2514 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2515 | * interface happily blocks "unblockable" signals like SIGKILL | |
2516 | * and friends. | |
2517 | */ | |
2518 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2519 | { | |
73ef4aeb ON |
2520 | struct task_struct *tsk = current; |
2521 | sigset_t newset; | |
1da177e4 | 2522 | |
73ef4aeb | 2523 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2524 | if (oldset) |
73ef4aeb | 2525 | *oldset = tsk->blocked; |
a26fd335 | 2526 | |
1da177e4 LT |
2527 | switch (how) { |
2528 | case SIG_BLOCK: | |
73ef4aeb | 2529 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2530 | break; |
2531 | case SIG_UNBLOCK: | |
702a5073 | 2532 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2533 | break; |
2534 | case SIG_SETMASK: | |
73ef4aeb | 2535 | newset = *set; |
1da177e4 LT |
2536 | break; |
2537 | default: | |
73ef4aeb | 2538 | return -EINVAL; |
1da177e4 | 2539 | } |
a26fd335 | 2540 | |
77097ae5 | 2541 | __set_current_blocked(&newset); |
73ef4aeb | 2542 | return 0; |
1da177e4 LT |
2543 | } |
2544 | ||
41c57892 RD |
2545 | /** |
2546 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2547 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2548 | * @nset: stores pending signals |
41c57892 RD |
2549 | * @oset: previous value of signal mask if non-null |
2550 | * @sigsetsize: size of sigset_t type | |
2551 | */ | |
bb7efee2 | 2552 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2553 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2554 | { |
1da177e4 | 2555 | sigset_t old_set, new_set; |
bb7efee2 | 2556 | int error; |
1da177e4 LT |
2557 | |
2558 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2559 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2560 | return -EINVAL; |
1da177e4 | 2561 | |
bb7efee2 ON |
2562 | old_set = current->blocked; |
2563 | ||
2564 | if (nset) { | |
2565 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2566 | return -EFAULT; | |
1da177e4 LT |
2567 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2568 | ||
bb7efee2 | 2569 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2570 | if (error) |
bb7efee2 ON |
2571 | return error; |
2572 | } | |
1da177e4 | 2573 | |
bb7efee2 ON |
2574 | if (oset) { |
2575 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2576 | return -EFAULT; | |
1da177e4 | 2577 | } |
bb7efee2 ON |
2578 | |
2579 | return 0; | |
1da177e4 LT |
2580 | } |
2581 | ||
322a56cb | 2582 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2583 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2584 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2585 | { |
322a56cb AV |
2586 | #ifdef __BIG_ENDIAN |
2587 | sigset_t old_set = current->blocked; | |
2588 | ||
2589 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2590 | if (sigsetsize != sizeof(sigset_t)) | |
2591 | return -EINVAL; | |
2592 | ||
2593 | if (nset) { | |
2594 | compat_sigset_t new32; | |
2595 | sigset_t new_set; | |
2596 | int error; | |
2597 | if (copy_from_user(&new32, nset, sizeof(compat_sigset_t))) | |
2598 | return -EFAULT; | |
2599 | ||
2600 | sigset_from_compat(&new_set, &new32); | |
2601 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2602 | ||
2603 | error = sigprocmask(how, &new_set, NULL); | |
2604 | if (error) | |
2605 | return error; | |
2606 | } | |
2607 | if (oset) { | |
2608 | compat_sigset_t old32; | |
2609 | sigset_to_compat(&old32, &old_set); | |
db61ec29 | 2610 | if (copy_to_user(oset, &old32, sizeof(compat_sigset_t))) |
322a56cb AV |
2611 | return -EFAULT; |
2612 | } | |
2613 | return 0; | |
2614 | #else | |
2615 | return sys_rt_sigprocmask(how, (sigset_t __user *)nset, | |
2616 | (sigset_t __user *)oset, sigsetsize); | |
2617 | #endif | |
2618 | } | |
2619 | #endif | |
1da177e4 | 2620 | |
fe9c1db2 | 2621 | static int do_sigpending(void *set, unsigned long sigsetsize) |
1da177e4 | 2622 | { |
1da177e4 | 2623 | if (sigsetsize > sizeof(sigset_t)) |
fe9c1db2 | 2624 | return -EINVAL; |
1da177e4 LT |
2625 | |
2626 | spin_lock_irq(¤t->sighand->siglock); | |
fe9c1db2 | 2627 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
2628 | ¤t->signal->shared_pending.signal); |
2629 | spin_unlock_irq(¤t->sighand->siglock); | |
2630 | ||
2631 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 AV |
2632 | sigandsets(set, ¤t->blocked, set); |
2633 | return 0; | |
5aba085e | 2634 | } |
1da177e4 | 2635 | |
41c57892 RD |
2636 | /** |
2637 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2638 | * while blocked | |
20f22ab4 | 2639 | * @uset: stores pending signals |
41c57892 RD |
2640 | * @sigsetsize: size of sigset_t type or larger |
2641 | */ | |
fe9c1db2 | 2642 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 2643 | { |
fe9c1db2 AV |
2644 | sigset_t set; |
2645 | int err = do_sigpending(&set, sigsetsize); | |
2646 | if (!err && copy_to_user(uset, &set, sigsetsize)) | |
2647 | err = -EFAULT; | |
2648 | return err; | |
2649 | } | |
2650 | ||
2651 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
2652 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
2653 | compat_size_t, sigsetsize) | |
1da177e4 | 2654 | { |
fe9c1db2 AV |
2655 | #ifdef __BIG_ENDIAN |
2656 | sigset_t set; | |
2657 | int err = do_sigpending(&set, sigsetsize); | |
2658 | if (!err) { | |
2659 | compat_sigset_t set32; | |
2660 | sigset_to_compat(&set32, &set); | |
2661 | /* we can get here only if sigsetsize <= sizeof(set) */ | |
2662 | if (copy_to_user(uset, &set32, sigsetsize)) | |
2663 | err = -EFAULT; | |
2664 | } | |
2665 | return err; | |
2666 | #else | |
2667 | return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize); | |
2668 | #endif | |
1da177e4 | 2669 | } |
fe9c1db2 | 2670 | #endif |
1da177e4 LT |
2671 | |
2672 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2673 | ||
ce395960 | 2674 | int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) |
1da177e4 LT |
2675 | { |
2676 | int err; | |
2677 | ||
2678 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2679 | return -EFAULT; | |
2680 | if (from->si_code < 0) | |
2681 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2682 | ? -EFAULT : 0; | |
2683 | /* | |
2684 | * If you change siginfo_t structure, please be sure | |
2685 | * this code is fixed accordingly. | |
fba2afaa DL |
2686 | * Please remember to update the signalfd_copyinfo() function |
2687 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2688 | * It should never copy any pad contained in the structure |
2689 | * to avoid security leaks, but must copy the generic | |
2690 | * 3 ints plus the relevant union member. | |
2691 | */ | |
2692 | err = __put_user(from->si_signo, &to->si_signo); | |
2693 | err |= __put_user(from->si_errno, &to->si_errno); | |
2694 | err |= __put_user((short)from->si_code, &to->si_code); | |
2695 | switch (from->si_code & __SI_MASK) { | |
2696 | case __SI_KILL: | |
2697 | err |= __put_user(from->si_pid, &to->si_pid); | |
2698 | err |= __put_user(from->si_uid, &to->si_uid); | |
2699 | break; | |
2700 | case __SI_TIMER: | |
2701 | err |= __put_user(from->si_tid, &to->si_tid); | |
2702 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2703 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2704 | break; | |
2705 | case __SI_POLL: | |
2706 | err |= __put_user(from->si_band, &to->si_band); | |
2707 | err |= __put_user(from->si_fd, &to->si_fd); | |
2708 | break; | |
2709 | case __SI_FAULT: | |
2710 | err |= __put_user(from->si_addr, &to->si_addr); | |
2711 | #ifdef __ARCH_SI_TRAPNO | |
2712 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2713 | #endif |
2714 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2715 | /* |
a337fdac | 2716 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2717 | * so check explicitly for the right codes here. |
a337fdac | 2718 | */ |
26135022 AA |
2719 | if (from->si_signo == SIGBUS && |
2720 | (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) | |
a337fdac | 2721 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); |
ee1b58d3 QR |
2722 | #endif |
2723 | #ifdef SEGV_BNDERR | |
26135022 AA |
2724 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) { |
2725 | err |= __put_user(from->si_lower, &to->si_lower); | |
2726 | err |= __put_user(from->si_upper, &to->si_upper); | |
2727 | } | |
cd0ea35f DH |
2728 | #endif |
2729 | #ifdef SEGV_PKUERR | |
2730 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR) | |
2731 | err |= __put_user(from->si_pkey, &to->si_pkey); | |
1da177e4 LT |
2732 | #endif |
2733 | break; | |
2734 | case __SI_CHLD: | |
2735 | err |= __put_user(from->si_pid, &to->si_pid); | |
2736 | err |= __put_user(from->si_uid, &to->si_uid); | |
2737 | err |= __put_user(from->si_status, &to->si_status); | |
2738 | err |= __put_user(from->si_utime, &to->si_utime); | |
2739 | err |= __put_user(from->si_stime, &to->si_stime); | |
2740 | break; | |
2741 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2742 | case __SI_MESGQ: /* But this is */ | |
2743 | err |= __put_user(from->si_pid, &to->si_pid); | |
2744 | err |= __put_user(from->si_uid, &to->si_uid); | |
2745 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2746 | break; | |
a0727e8c WD |
2747 | #ifdef __ARCH_SIGSYS |
2748 | case __SI_SYS: | |
2749 | err |= __put_user(from->si_call_addr, &to->si_call_addr); | |
2750 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2751 | err |= __put_user(from->si_arch, &to->si_arch); | |
2752 | break; | |
2753 | #endif | |
1da177e4 LT |
2754 | default: /* this is just in case for now ... */ |
2755 | err |= __put_user(from->si_pid, &to->si_pid); | |
2756 | err |= __put_user(from->si_uid, &to->si_uid); | |
2757 | break; | |
2758 | } | |
2759 | return err; | |
2760 | } | |
2761 | ||
2762 | #endif | |
2763 | ||
943df148 ON |
2764 | /** |
2765 | * do_sigtimedwait - wait for queued signals specified in @which | |
2766 | * @which: queued signals to wait for | |
2767 | * @info: if non-null, the signal's siginfo is returned here | |
2768 | * @ts: upper bound on process time suspension | |
2769 | */ | |
2770 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info, | |
2b1ecc3d | 2771 | const struct timespec *ts) |
943df148 | 2772 | { |
2456e855 | 2773 | ktime_t *to = NULL, timeout = KTIME_MAX; |
943df148 | 2774 | struct task_struct *tsk = current; |
943df148 | 2775 | sigset_t mask = *which; |
2b1ecc3d | 2776 | int sig, ret = 0; |
943df148 ON |
2777 | |
2778 | if (ts) { | |
2779 | if (!timespec_valid(ts)) | |
2780 | return -EINVAL; | |
2b1ecc3d TG |
2781 | timeout = timespec_to_ktime(*ts); |
2782 | to = &timeout; | |
943df148 ON |
2783 | } |
2784 | ||
2785 | /* | |
2786 | * Invert the set of allowed signals to get those we want to block. | |
2787 | */ | |
2788 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2789 | signotset(&mask); | |
2790 | ||
2791 | spin_lock_irq(&tsk->sighand->siglock); | |
2792 | sig = dequeue_signal(tsk, &mask, info); | |
2456e855 | 2793 | if (!sig && timeout) { |
943df148 ON |
2794 | /* |
2795 | * None ready, temporarily unblock those we're interested | |
2796 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2797 | * they arrive. Unblocking is always fine, we can avoid |
2798 | * set_current_blocked(). | |
943df148 ON |
2799 | */ |
2800 | tsk->real_blocked = tsk->blocked; | |
2801 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2802 | recalc_sigpending(); | |
2803 | spin_unlock_irq(&tsk->sighand->siglock); | |
2804 | ||
2b1ecc3d TG |
2805 | __set_current_state(TASK_INTERRUPTIBLE); |
2806 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, | |
2807 | HRTIMER_MODE_REL); | |
943df148 | 2808 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2809 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 2810 | sigemptyset(&tsk->real_blocked); |
b182801a | 2811 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2812 | } |
2813 | spin_unlock_irq(&tsk->sighand->siglock); | |
2814 | ||
2815 | if (sig) | |
2816 | return sig; | |
2b1ecc3d | 2817 | return ret ? -EINTR : -EAGAIN; |
943df148 ON |
2818 | } |
2819 | ||
41c57892 RD |
2820 | /** |
2821 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2822 | * in @uthese | |
2823 | * @uthese: queued signals to wait for | |
2824 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2825 | * @uts: upper bound on process time suspension | |
2826 | * @sigsetsize: size of sigset_t type | |
2827 | */ | |
17da2bd9 HC |
2828 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2829 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2830 | size_t, sigsetsize) | |
1da177e4 | 2831 | { |
1da177e4 LT |
2832 | sigset_t these; |
2833 | struct timespec ts; | |
2834 | siginfo_t info; | |
943df148 | 2835 | int ret; |
1da177e4 LT |
2836 | |
2837 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2838 | if (sigsetsize != sizeof(sigset_t)) | |
2839 | return -EINVAL; | |
2840 | ||
2841 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2842 | return -EFAULT; | |
5aba085e | 2843 | |
1da177e4 LT |
2844 | if (uts) { |
2845 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2846 | return -EFAULT; | |
1da177e4 LT |
2847 | } |
2848 | ||
943df148 | 2849 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2850 | |
943df148 ON |
2851 | if (ret > 0 && uinfo) { |
2852 | if (copy_siginfo_to_user(uinfo, &info)) | |
2853 | ret = -EFAULT; | |
1da177e4 LT |
2854 | } |
2855 | ||
2856 | return ret; | |
2857 | } | |
2858 | ||
41c57892 RD |
2859 | /** |
2860 | * sys_kill - send a signal to a process | |
2861 | * @pid: the PID of the process | |
2862 | * @sig: signal to be sent | |
2863 | */ | |
17da2bd9 | 2864 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2865 | { |
2866 | struct siginfo info; | |
2867 | ||
2868 | info.si_signo = sig; | |
2869 | info.si_errno = 0; | |
2870 | info.si_code = SI_USER; | |
b488893a | 2871 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2872 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2873 | |
2874 | return kill_something_info(sig, &info, pid); | |
2875 | } | |
2876 | ||
30b4ae8a TG |
2877 | static int |
2878 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2879 | { |
1da177e4 | 2880 | struct task_struct *p; |
30b4ae8a | 2881 | int error = -ESRCH; |
1da177e4 | 2882 | |
3547ff3a | 2883 | rcu_read_lock(); |
228ebcbe | 2884 | p = find_task_by_vpid(pid); |
b488893a | 2885 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2886 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2887 | /* |
2888 | * The null signal is a permissions and process existence | |
2889 | * probe. No signal is actually delivered. | |
2890 | */ | |
4a30debf ON |
2891 | if (!error && sig) { |
2892 | error = do_send_sig_info(sig, info, p, false); | |
2893 | /* | |
2894 | * If lock_task_sighand() failed we pretend the task | |
2895 | * dies after receiving the signal. The window is tiny, | |
2896 | * and the signal is private anyway. | |
2897 | */ | |
2898 | if (unlikely(error == -ESRCH)) | |
2899 | error = 0; | |
1da177e4 LT |
2900 | } |
2901 | } | |
3547ff3a | 2902 | rcu_read_unlock(); |
6dd69f10 | 2903 | |
1da177e4 LT |
2904 | return error; |
2905 | } | |
2906 | ||
30b4ae8a TG |
2907 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2908 | { | |
b9e146d8 | 2909 | struct siginfo info = {}; |
30b4ae8a TG |
2910 | |
2911 | info.si_signo = sig; | |
2912 | info.si_errno = 0; | |
2913 | info.si_code = SI_TKILL; | |
2914 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 2915 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
2916 | |
2917 | return do_send_specific(tgid, pid, sig, &info); | |
2918 | } | |
2919 | ||
6dd69f10 VL |
2920 | /** |
2921 | * sys_tgkill - send signal to one specific thread | |
2922 | * @tgid: the thread group ID of the thread | |
2923 | * @pid: the PID of the thread | |
2924 | * @sig: signal to be sent | |
2925 | * | |
72fd4a35 | 2926 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2927 | * exists but it's not belonging to the target process anymore. This |
2928 | * method solves the problem of threads exiting and PIDs getting reused. | |
2929 | */ | |
a5f8fa9e | 2930 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2931 | { |
2932 | /* This is only valid for single tasks */ | |
2933 | if (pid <= 0 || tgid <= 0) | |
2934 | return -EINVAL; | |
2935 | ||
2936 | return do_tkill(tgid, pid, sig); | |
2937 | } | |
2938 | ||
41c57892 RD |
2939 | /** |
2940 | * sys_tkill - send signal to one specific task | |
2941 | * @pid: the PID of the task | |
2942 | * @sig: signal to be sent | |
2943 | * | |
1da177e4 LT |
2944 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2945 | */ | |
a5f8fa9e | 2946 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2947 | { |
1da177e4 LT |
2948 | /* This is only valid for single tasks */ |
2949 | if (pid <= 0) | |
2950 | return -EINVAL; | |
2951 | ||
6dd69f10 | 2952 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2953 | } |
2954 | ||
75907d4d AV |
2955 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) |
2956 | { | |
2957 | /* Not even root can pretend to send signals from the kernel. | |
2958 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
2959 | */ | |
66dd34ad | 2960 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
69828dce | 2961 | (task_pid_vnr(current) != pid)) |
75907d4d | 2962 | return -EPERM; |
69828dce | 2963 | |
75907d4d AV |
2964 | info->si_signo = sig; |
2965 | ||
2966 | /* POSIX.1b doesn't mention process groups. */ | |
2967 | return kill_proc_info(sig, info, pid); | |
2968 | } | |
2969 | ||
41c57892 RD |
2970 | /** |
2971 | * sys_rt_sigqueueinfo - send signal information to a signal | |
2972 | * @pid: the PID of the thread | |
2973 | * @sig: signal to be sent | |
2974 | * @uinfo: signal info to be sent | |
2975 | */ | |
a5f8fa9e HC |
2976 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2977 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2978 | { |
2979 | siginfo_t info; | |
1da177e4 LT |
2980 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) |
2981 | return -EFAULT; | |
75907d4d AV |
2982 | return do_rt_sigqueueinfo(pid, sig, &info); |
2983 | } | |
1da177e4 | 2984 | |
75907d4d | 2985 | #ifdef CONFIG_COMPAT |
75907d4d AV |
2986 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
2987 | compat_pid_t, pid, | |
2988 | int, sig, | |
2989 | struct compat_siginfo __user *, uinfo) | |
2990 | { | |
3c00cb5e | 2991 | siginfo_t info = {}; |
75907d4d AV |
2992 | int ret = copy_siginfo_from_user32(&info, uinfo); |
2993 | if (unlikely(ret)) | |
2994 | return ret; | |
2995 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 2996 | } |
75907d4d | 2997 | #endif |
1da177e4 | 2998 | |
9aae8fc0 | 2999 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
62ab4505 TG |
3000 | { |
3001 | /* This is only valid for single tasks */ | |
3002 | if (pid <= 0 || tgid <= 0) | |
3003 | return -EINVAL; | |
3004 | ||
3005 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3006 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3007 | */ | |
69828dce VD |
3008 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3009 | (task_pid_vnr(current) != pid)) | |
62ab4505 | 3010 | return -EPERM; |
69828dce | 3011 | |
62ab4505 TG |
3012 | info->si_signo = sig; |
3013 | ||
3014 | return do_send_specific(tgid, pid, sig, info); | |
3015 | } | |
3016 | ||
3017 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3018 | siginfo_t __user *, uinfo) | |
3019 | { | |
3020 | siginfo_t info; | |
3021 | ||
3022 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3023 | return -EFAULT; | |
3024 | ||
3025 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3026 | } | |
3027 | ||
9aae8fc0 AV |
3028 | #ifdef CONFIG_COMPAT |
3029 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3030 | compat_pid_t, tgid, | |
3031 | compat_pid_t, pid, | |
3032 | int, sig, | |
3033 | struct compat_siginfo __user *, uinfo) | |
3034 | { | |
3c00cb5e | 3035 | siginfo_t info = {}; |
9aae8fc0 AV |
3036 | |
3037 | if (copy_siginfo_from_user32(&info, uinfo)) | |
3038 | return -EFAULT; | |
3039 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3040 | } | |
3041 | #endif | |
3042 | ||
0341729b | 3043 | /* |
b4e74264 | 3044 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
0341729b | 3045 | */ |
b4e74264 | 3046 | void kernel_sigaction(int sig, __sighandler_t action) |
0341729b | 3047 | { |
ec5955b8 | 3048 | spin_lock_irq(¤t->sighand->siglock); |
b4e74264 ON |
3049 | current->sighand->action[sig - 1].sa.sa_handler = action; |
3050 | if (action == SIG_IGN) { | |
3051 | sigset_t mask; | |
0341729b | 3052 | |
b4e74264 ON |
3053 | sigemptyset(&mask); |
3054 | sigaddset(&mask, sig); | |
580d34e4 | 3055 | |
b4e74264 ON |
3056 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
3057 | flush_sigqueue_mask(&mask, ¤t->pending); | |
3058 | recalc_sigpending(); | |
3059 | } | |
0341729b ON |
3060 | spin_unlock_irq(¤t->sighand->siglock); |
3061 | } | |
b4e74264 | 3062 | EXPORT_SYMBOL(kernel_sigaction); |
0341729b | 3063 | |
68463510 DS |
3064 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
3065 | struct k_sigaction *oact) | |
3066 | { | |
3067 | } | |
3068 | ||
88531f72 | 3069 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3070 | { |
afe2b038 | 3071 | struct task_struct *p = current, *t; |
1da177e4 | 3072 | struct k_sigaction *k; |
71fabd5e | 3073 | sigset_t mask; |
1da177e4 | 3074 | |
7ed20e1a | 3075 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3076 | return -EINVAL; |
3077 | ||
afe2b038 | 3078 | k = &p->sighand->action[sig-1]; |
1da177e4 | 3079 | |
afe2b038 | 3080 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
3081 | if (oact) |
3082 | *oact = *k; | |
3083 | ||
68463510 DS |
3084 | sigaction_compat_abi(act, oact); |
3085 | ||
1da177e4 | 3086 | if (act) { |
9ac95f2f ON |
3087 | sigdelsetmask(&act->sa.sa_mask, |
3088 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3089 | *k = *act; |
1da177e4 LT |
3090 | /* |
3091 | * POSIX 3.3.1.3: | |
3092 | * "Setting a signal action to SIG_IGN for a signal that is | |
3093 | * pending shall cause the pending signal to be discarded, | |
3094 | * whether or not it is blocked." | |
3095 | * | |
3096 | * "Setting a signal action to SIG_DFL for a signal that is | |
3097 | * pending and whose default action is to ignore the signal | |
3098 | * (for example, SIGCHLD), shall cause the pending signal to | |
3099 | * be discarded, whether or not it is blocked" | |
3100 | */ | |
afe2b038 | 3101 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
71fabd5e GA |
3102 | sigemptyset(&mask); |
3103 | sigaddset(&mask, sig); | |
afe2b038 ON |
3104 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
3105 | for_each_thread(p, t) | |
c09c1441 | 3106 | flush_sigqueue_mask(&mask, &t->pending); |
1da177e4 | 3107 | } |
1da177e4 LT |
3108 | } |
3109 | ||
afe2b038 | 3110 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
3111 | return 0; |
3112 | } | |
3113 | ||
c09c1441 | 3114 | static int |
1da177e4 LT |
3115 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) |
3116 | { | |
3117 | stack_t oss; | |
3118 | int error; | |
3119 | ||
0083fc2c LT |
3120 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
3121 | oss.ss_size = current->sas_ss_size; | |
0318bc8a AL |
3122 | oss.ss_flags = sas_ss_flags(sp) | |
3123 | (current->sas_ss_flags & SS_FLAG_BITS); | |
1da177e4 LT |
3124 | |
3125 | if (uss) { | |
3126 | void __user *ss_sp; | |
3127 | size_t ss_size; | |
407bc16a SS |
3128 | unsigned ss_flags; |
3129 | int ss_mode; | |
1da177e4 LT |
3130 | |
3131 | error = -EFAULT; | |
0dd8486b LT |
3132 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
3133 | goto out; | |
3134 | error = __get_user(ss_sp, &uss->ss_sp) | | |
3135 | __get_user(ss_flags, &uss->ss_flags) | | |
3136 | __get_user(ss_size, &uss->ss_size); | |
3137 | if (error) | |
1da177e4 LT |
3138 | goto out; |
3139 | ||
3140 | error = -EPERM; | |
3141 | if (on_sig_stack(sp)) | |
3142 | goto out; | |
3143 | ||
407bc16a | 3144 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
1da177e4 | 3145 | error = -EINVAL; |
407bc16a SS |
3146 | if (ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
3147 | ss_mode != 0) | |
1da177e4 LT |
3148 | goto out; |
3149 | ||
407bc16a | 3150 | if (ss_mode == SS_DISABLE) { |
1da177e4 LT |
3151 | ss_size = 0; |
3152 | ss_sp = NULL; | |
3153 | } else { | |
3154 | error = -ENOMEM; | |
3155 | if (ss_size < MINSIGSTKSZ) | |
3156 | goto out; | |
3157 | } | |
3158 | ||
3159 | current->sas_ss_sp = (unsigned long) ss_sp; | |
3160 | current->sas_ss_size = ss_size; | |
2a742138 | 3161 | current->sas_ss_flags = ss_flags; |
1da177e4 LT |
3162 | } |
3163 | ||
0083fc2c | 3164 | error = 0; |
1da177e4 LT |
3165 | if (uoss) { |
3166 | error = -EFAULT; | |
0083fc2c | 3167 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 3168 | goto out; |
0083fc2c LT |
3169 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
3170 | __put_user(oss.ss_size, &uoss->ss_size) | | |
3171 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
3172 | } |
3173 | ||
1da177e4 LT |
3174 | out: |
3175 | return error; | |
3176 | } | |
6bf9adfc AV |
3177 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3178 | { | |
3179 | return do_sigaltstack(uss, uoss, current_user_stack_pointer()); | |
3180 | } | |
1da177e4 | 3181 | |
5c49574f AV |
3182 | int restore_altstack(const stack_t __user *uss) |
3183 | { | |
3184 | int err = do_sigaltstack(uss, NULL, current_user_stack_pointer()); | |
3185 | /* squash all but EFAULT for now */ | |
3186 | return err == -EFAULT ? err : 0; | |
3187 | } | |
3188 | ||
c40702c4 AV |
3189 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3190 | { | |
3191 | struct task_struct *t = current; | |
2a742138 SS |
3192 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
3193 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3194 | __put_user(t->sas_ss_size, &uss->ss_size); |
2a742138 SS |
3195 | if (err) |
3196 | return err; | |
3197 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3198 | sas_ss_reset(t); | |
3199 | return 0; | |
c40702c4 AV |
3200 | } |
3201 | ||
90268439 | 3202 | #ifdef CONFIG_COMPAT |
90228fc1 AV |
3203 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
3204 | const compat_stack_t __user *, uss_ptr, | |
3205 | compat_stack_t __user *, uoss_ptr) | |
90268439 AV |
3206 | { |
3207 | stack_t uss, uoss; | |
3208 | int ret; | |
3209 | mm_segment_t seg; | |
3210 | ||
3211 | if (uss_ptr) { | |
3212 | compat_stack_t uss32; | |
3213 | ||
3214 | memset(&uss, 0, sizeof(stack_t)); | |
3215 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) | |
3216 | return -EFAULT; | |
3217 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
3218 | uss.ss_flags = uss32.ss_flags; | |
3219 | uss.ss_size = uss32.ss_size; | |
3220 | } | |
3221 | seg = get_fs(); | |
3222 | set_fs(KERNEL_DS); | |
3223 | ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), | |
3224 | (stack_t __force __user *) &uoss, | |
3225 | compat_user_stack_pointer()); | |
3226 | set_fs(seg); | |
3227 | if (ret >= 0 && uoss_ptr) { | |
3228 | if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) || | |
3229 | __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) || | |
3230 | __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) || | |
3231 | __put_user(uoss.ss_size, &uoss_ptr->ss_size)) | |
3232 | ret = -EFAULT; | |
3233 | } | |
3234 | return ret; | |
3235 | } | |
3236 | ||
3237 | int compat_restore_altstack(const compat_stack_t __user *uss) | |
3238 | { | |
3239 | int err = compat_sys_sigaltstack(uss, NULL); | |
3240 | /* squash all but -EFAULT for now */ | |
3241 | return err == -EFAULT ? err : 0; | |
3242 | } | |
c40702c4 AV |
3243 | |
3244 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
3245 | { | |
441398d3 | 3246 | int err; |
c40702c4 | 3247 | struct task_struct *t = current; |
441398d3 SS |
3248 | err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
3249 | &uss->ss_sp) | | |
3250 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3251 | __put_user(t->sas_ss_size, &uss->ss_size); |
441398d3 SS |
3252 | if (err) |
3253 | return err; | |
3254 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3255 | sas_ss_reset(t); | |
3256 | return 0; | |
c40702c4 | 3257 | } |
90268439 | 3258 | #endif |
1da177e4 LT |
3259 | |
3260 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3261 | ||
41c57892 RD |
3262 | /** |
3263 | * sys_sigpending - examine pending signals | |
3264 | * @set: where mask of pending signal is returned | |
3265 | */ | |
b290ebe2 | 3266 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 | 3267 | { |
fe9c1db2 | 3268 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); |
1da177e4 LT |
3269 | } |
3270 | ||
3271 | #endif | |
3272 | ||
3273 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3274 | /** |
3275 | * sys_sigprocmask - examine and change blocked signals | |
3276 | * @how: whether to add, remove, or set signals | |
b013c399 | 3277 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3278 | * @oset: previous value of signal mask if non-null |
3279 | * | |
5aba085e RD |
3280 | * Some platforms have their own version with special arguments; |
3281 | * others support only sys_rt_sigprocmask. | |
3282 | */ | |
1da177e4 | 3283 | |
b013c399 | 3284 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3285 | old_sigset_t __user *, oset) |
1da177e4 | 3286 | { |
1da177e4 | 3287 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3288 | sigset_t new_blocked; |
1da177e4 | 3289 | |
b013c399 | 3290 | old_set = current->blocked.sig[0]; |
1da177e4 | 3291 | |
b013c399 ON |
3292 | if (nset) { |
3293 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3294 | return -EFAULT; | |
1da177e4 | 3295 | |
2e4f7c77 | 3296 | new_blocked = current->blocked; |
1da177e4 | 3297 | |
1da177e4 | 3298 | switch (how) { |
1da177e4 | 3299 | case SIG_BLOCK: |
2e4f7c77 | 3300 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3301 | break; |
3302 | case SIG_UNBLOCK: | |
2e4f7c77 | 3303 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3304 | break; |
3305 | case SIG_SETMASK: | |
2e4f7c77 | 3306 | new_blocked.sig[0] = new_set; |
1da177e4 | 3307 | break; |
2e4f7c77 ON |
3308 | default: |
3309 | return -EINVAL; | |
1da177e4 LT |
3310 | } |
3311 | ||
0c4a8423 | 3312 | set_current_blocked(&new_blocked); |
b013c399 ON |
3313 | } |
3314 | ||
3315 | if (oset) { | |
1da177e4 | 3316 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3317 | return -EFAULT; |
1da177e4 | 3318 | } |
b013c399 ON |
3319 | |
3320 | return 0; | |
1da177e4 LT |
3321 | } |
3322 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3323 | ||
eaca6eae | 3324 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
3325 | /** |
3326 | * sys_rt_sigaction - alter an action taken by a process | |
3327 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3328 | * @act: new sigaction |
3329 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3330 | * @sigsetsize: size of sigset_t type |
3331 | */ | |
d4e82042 HC |
3332 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3333 | const struct sigaction __user *, act, | |
3334 | struct sigaction __user *, oact, | |
3335 | size_t, sigsetsize) | |
1da177e4 LT |
3336 | { |
3337 | struct k_sigaction new_sa, old_sa; | |
3338 | int ret = -EINVAL; | |
3339 | ||
3340 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3341 | if (sigsetsize != sizeof(sigset_t)) | |
3342 | goto out; | |
3343 | ||
3344 | if (act) { | |
3345 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3346 | return -EFAULT; | |
3347 | } | |
3348 | ||
3349 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3350 | ||
3351 | if (!ret && oact) { | |
3352 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3353 | return -EFAULT; | |
3354 | } | |
3355 | out: | |
3356 | return ret; | |
3357 | } | |
08d32fe5 | 3358 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
3359 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3360 | const struct compat_sigaction __user *, act, | |
3361 | struct compat_sigaction __user *, oact, | |
3362 | compat_size_t, sigsetsize) | |
3363 | { | |
3364 | struct k_sigaction new_ka, old_ka; | |
3365 | compat_sigset_t mask; | |
3366 | #ifdef __ARCH_HAS_SA_RESTORER | |
3367 | compat_uptr_t restorer; | |
3368 | #endif | |
3369 | int ret; | |
3370 | ||
3371 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3372 | if (sigsetsize != sizeof(compat_sigset_t)) | |
3373 | return -EINVAL; | |
3374 | ||
3375 | if (act) { | |
3376 | compat_uptr_t handler; | |
3377 | ret = get_user(handler, &act->sa_handler); | |
3378 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3379 | #ifdef __ARCH_HAS_SA_RESTORER | |
3380 | ret |= get_user(restorer, &act->sa_restorer); | |
3381 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3382 | #endif | |
3383 | ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask)); | |
3ddc5b46 | 3384 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
3385 | if (ret) |
3386 | return -EFAULT; | |
3387 | sigset_from_compat(&new_ka.sa.sa_mask, &mask); | |
3388 | } | |
3389 | ||
3390 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3391 | if (!ret && oact) { | |
3392 | sigset_to_compat(&mask, &old_ka.sa.sa_mask); | |
3393 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3394 | &oact->sa_handler); | |
3395 | ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask)); | |
3ddc5b46 | 3396 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
3397 | #ifdef __ARCH_HAS_SA_RESTORER |
3398 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3399 | &oact->sa_restorer); | |
3400 | #endif | |
3401 | } | |
3402 | return ret; | |
3403 | } | |
3404 | #endif | |
eaca6eae | 3405 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 3406 | |
495dfbf7 AV |
3407 | #ifdef CONFIG_OLD_SIGACTION |
3408 | SYSCALL_DEFINE3(sigaction, int, sig, | |
3409 | const struct old_sigaction __user *, act, | |
3410 | struct old_sigaction __user *, oact) | |
3411 | { | |
3412 | struct k_sigaction new_ka, old_ka; | |
3413 | int ret; | |
3414 | ||
3415 | if (act) { | |
3416 | old_sigset_t mask; | |
3417 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3418 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
3419 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
3420 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3421 | __get_user(mask, &act->sa_mask)) | |
3422 | return -EFAULT; | |
3423 | #ifdef __ARCH_HAS_KA_RESTORER | |
3424 | new_ka.ka_restorer = NULL; | |
3425 | #endif | |
3426 | siginitset(&new_ka.sa.sa_mask, mask); | |
3427 | } | |
3428 | ||
3429 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3430 | ||
3431 | if (!ret && oact) { | |
3432 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3433 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
3434 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
3435 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3436 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3437 | return -EFAULT; | |
3438 | } | |
3439 | ||
3440 | return ret; | |
3441 | } | |
3442 | #endif | |
3443 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
3444 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
3445 | const struct compat_old_sigaction __user *, act, | |
3446 | struct compat_old_sigaction __user *, oact) | |
3447 | { | |
3448 | struct k_sigaction new_ka, old_ka; | |
3449 | int ret; | |
3450 | compat_old_sigset_t mask; | |
3451 | compat_uptr_t handler, restorer; | |
3452 | ||
3453 | if (act) { | |
3454 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3455 | __get_user(handler, &act->sa_handler) || | |
3456 | __get_user(restorer, &act->sa_restorer) || | |
3457 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3458 | __get_user(mask, &act->sa_mask)) | |
3459 | return -EFAULT; | |
3460 | ||
3461 | #ifdef __ARCH_HAS_KA_RESTORER | |
3462 | new_ka.ka_restorer = NULL; | |
3463 | #endif | |
3464 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3465 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3466 | siginitset(&new_ka.sa.sa_mask, mask); | |
3467 | } | |
3468 | ||
3469 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3470 | ||
3471 | if (!ret && oact) { | |
3472 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3473 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3474 | &oact->sa_handler) || | |
3475 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3476 | &oact->sa_restorer) || | |
3477 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3478 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3479 | return -EFAULT; | |
3480 | } | |
3481 | return ret; | |
3482 | } | |
3483 | #endif | |
1da177e4 | 3484 | |
f6187769 | 3485 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
3486 | |
3487 | /* | |
3488 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3489 | */ | |
a5f8fa9e | 3490 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3491 | { |
3492 | /* SMP safe */ | |
3493 | return current->blocked.sig[0]; | |
3494 | } | |
3495 | ||
a5f8fa9e | 3496 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3497 | { |
c1095c6d ON |
3498 | int old = current->blocked.sig[0]; |
3499 | sigset_t newset; | |
1da177e4 | 3500 | |
5ba53ff6 | 3501 | siginitset(&newset, newmask); |
c1095c6d | 3502 | set_current_blocked(&newset); |
1da177e4 LT |
3503 | |
3504 | return old; | |
3505 | } | |
f6187769 | 3506 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
3507 | |
3508 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3509 | /* | |
3510 | * For backwards compatibility. Functionality superseded by sigaction. | |
3511 | */ | |
a5f8fa9e | 3512 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3513 | { |
3514 | struct k_sigaction new_sa, old_sa; | |
3515 | int ret; | |
3516 | ||
3517 | new_sa.sa.sa_handler = handler; | |
3518 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3519 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3520 | |
3521 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3522 | ||
3523 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3524 | } | |
3525 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3526 | ||
3527 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3528 | ||
a5f8fa9e | 3529 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3530 | { |
d92fcf05 | 3531 | while (!signal_pending(current)) { |
1df01355 | 3532 | __set_current_state(TASK_INTERRUPTIBLE); |
d92fcf05 ON |
3533 | schedule(); |
3534 | } | |
1da177e4 LT |
3535 | return -ERESTARTNOHAND; |
3536 | } | |
3537 | ||
3538 | #endif | |
3539 | ||
9d8a7652 | 3540 | static int sigsuspend(sigset_t *set) |
68f3f16d | 3541 | { |
68f3f16d AV |
3542 | current->saved_sigmask = current->blocked; |
3543 | set_current_blocked(set); | |
3544 | ||
823dd322 SL |
3545 | while (!signal_pending(current)) { |
3546 | __set_current_state(TASK_INTERRUPTIBLE); | |
3547 | schedule(); | |
3548 | } | |
68f3f16d AV |
3549 | set_restore_sigmask(); |
3550 | return -ERESTARTNOHAND; | |
3551 | } | |
68f3f16d | 3552 | |
41c57892 RD |
3553 | /** |
3554 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3555 | * @unewset value until a signal is received | |
3556 | * @unewset: new signal mask value | |
3557 | * @sigsetsize: size of sigset_t type | |
3558 | */ | |
d4e82042 | 3559 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3560 | { |
3561 | sigset_t newset; | |
3562 | ||
3563 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3564 | if (sigsetsize != sizeof(sigset_t)) | |
3565 | return -EINVAL; | |
3566 | ||
3567 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3568 | return -EFAULT; | |
68f3f16d | 3569 | return sigsuspend(&newset); |
150256d8 | 3570 | } |
ad4b65a4 AV |
3571 | |
3572 | #ifdef CONFIG_COMPAT | |
3573 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
3574 | { | |
3575 | #ifdef __BIG_ENDIAN | |
3576 | sigset_t newset; | |
3577 | compat_sigset_t newset32; | |
3578 | ||
3579 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3580 | if (sigsetsize != sizeof(sigset_t)) | |
3581 | return -EINVAL; | |
3582 | ||
3583 | if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t))) | |
3584 | return -EFAULT; | |
3585 | sigset_from_compat(&newset, &newset32); | |
3586 | return sigsuspend(&newset); | |
3587 | #else | |
3588 | /* on little-endian bitmaps don't care about granularity */ | |
3589 | return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize); | |
3590 | #endif | |
3591 | } | |
3592 | #endif | |
150256d8 | 3593 | |
0a0e8cdf AV |
3594 | #ifdef CONFIG_OLD_SIGSUSPEND |
3595 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
3596 | { | |
3597 | sigset_t blocked; | |
3598 | siginitset(&blocked, mask); | |
3599 | return sigsuspend(&blocked); | |
3600 | } | |
3601 | #endif | |
3602 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
3603 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
3604 | { | |
3605 | sigset_t blocked; | |
3606 | siginitset(&blocked, mask); | |
3607 | return sigsuspend(&blocked); | |
3608 | } | |
3609 | #endif | |
150256d8 | 3610 | |
52f5684c | 3611 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
3612 | { |
3613 | return NULL; | |
3614 | } | |
3615 | ||
1da177e4 LT |
3616 | void __init signals_init(void) |
3617 | { | |
41b27154 HD |
3618 | /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */ |
3619 | BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE | |
3620 | != offsetof(struct siginfo, _sifields._pad)); | |
3621 | ||
0a31bd5f | 3622 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3623 | } |
67fc4e0c JW |
3624 | |
3625 | #ifdef CONFIG_KGDB_KDB | |
3626 | #include <linux/kdb.h> | |
3627 | /* | |
3628 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3629 | * signal internals. This function checks if the required locks are | |
3630 | * available before calling the main signal code, to avoid kdb | |
3631 | * deadlocks. | |
3632 | */ | |
3633 | void | |
3634 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3635 | { | |
3636 | static struct task_struct *kdb_prev_t; | |
3637 | int sig, new_t; | |
3638 | if (!spin_trylock(&t->sighand->siglock)) { | |
3639 | kdb_printf("Can't do kill command now.\n" | |
3640 | "The sigmask lock is held somewhere else in " | |
3641 | "kernel, try again later\n"); | |
3642 | return; | |
3643 | } | |
3644 | spin_unlock(&t->sighand->siglock); | |
3645 | new_t = kdb_prev_t != t; | |
3646 | kdb_prev_t = t; | |
3647 | if (t->state != TASK_RUNNING && new_t) { | |
3648 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3649 | "kdb risks deadlock\n" | |
3650 | "on the run queue locks. " | |
3651 | "The signal has _not_ been sent.\n" | |
3652 | "Reissue the kill command if you want to risk " | |
3653 | "the deadlock.\n"); | |
3654 | return; | |
3655 | } | |
3656 | sig = info->si_signo; | |
3657 | if (send_sig_info(sig, info, t)) | |
3658 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3659 | sig, t->pid); | |
3660 | else | |
3661 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3662 | } | |
3663 | #endif /* CONFIG_KGDB_KDB */ |