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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> |
32ef5517 | 21 | #include <linux/sched/cputime.h> |
1da177e4 LT |
22 | #include <linux/fs.h> |
23 | #include <linux/tty.h> | |
24 | #include <linux/binfmts.h> | |
179899fd | 25 | #include <linux/coredump.h> |
1da177e4 LT |
26 | #include <linux/security.h> |
27 | #include <linux/syscalls.h> | |
28 | #include <linux/ptrace.h> | |
7ed20e1a | 29 | #include <linux/signal.h> |
fba2afaa | 30 | #include <linux/signalfd.h> |
f84d49b2 | 31 | #include <linux/ratelimit.h> |
35de254d | 32 | #include <linux/tracehook.h> |
c59ede7b | 33 | #include <linux/capability.h> |
7dfb7103 | 34 | #include <linux/freezer.h> |
84d73786 SB |
35 | #include <linux/pid_namespace.h> |
36 | #include <linux/nsproxy.h> | |
6b550f94 | 37 | #include <linux/user_namespace.h> |
0326f5a9 | 38 | #include <linux/uprobes.h> |
90268439 | 39 | #include <linux/compat.h> |
2b5faa4c | 40 | #include <linux/cn_proc.h> |
52f5684c GID |
41 | #include <linux/compiler.h> |
42 | ||
d1eb650f MH |
43 | #define CREATE_TRACE_POINTS |
44 | #include <trace/events/signal.h> | |
84d73786 | 45 | |
1da177e4 | 46 | #include <asm/param.h> |
7c0f6ba6 | 47 | #include <linux/uaccess.h> |
1da177e4 LT |
48 | #include <asm/unistd.h> |
49 | #include <asm/siginfo.h> | |
d550bbd4 | 50 | #include <asm/cacheflush.h> |
e1396065 | 51 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
52 | |
53 | /* | |
54 | * SLAB caches for signal bits. | |
55 | */ | |
56 | ||
e18b890b | 57 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 58 | |
f84d49b2 NO |
59 | int print_fatal_signals __read_mostly; |
60 | ||
35de254d | 61 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 62 | { |
35de254d RM |
63 | return t->sighand->action[sig - 1].sa.sa_handler; |
64 | } | |
93585eea | 65 | |
35de254d RM |
66 | static int sig_handler_ignored(void __user *handler, int sig) |
67 | { | |
93585eea | 68 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
69 | return handler == SIG_IGN || |
70 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
71 | } | |
1da177e4 | 72 | |
def8cf72 | 73 | static int sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 74 | { |
35de254d | 75 | void __user *handler; |
1da177e4 | 76 | |
f008faff ON |
77 | handler = sig_handler(t, sig); |
78 | ||
79 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
def8cf72 | 80 | handler == SIG_DFL && !force) |
f008faff ON |
81 | return 1; |
82 | ||
83 | return sig_handler_ignored(handler, sig); | |
84 | } | |
85 | ||
def8cf72 | 86 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 87 | { |
1da177e4 LT |
88 | /* |
89 | * Blocked signals are never ignored, since the | |
90 | * signal handler may change by the time it is | |
91 | * unblocked. | |
92 | */ | |
325d22df | 93 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
94 | return 0; |
95 | ||
def8cf72 | 96 | if (!sig_task_ignored(t, sig, force)) |
35de254d RM |
97 | return 0; |
98 | ||
99 | /* | |
100 | * Tracers may want to know about even ignored signals. | |
101 | */ | |
a288eecc | 102 | return !t->ptrace; |
1da177e4 LT |
103 | } |
104 | ||
105 | /* | |
106 | * Re-calculate pending state from the set of locally pending | |
107 | * signals, globally pending signals, and blocked signals. | |
108 | */ | |
109 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
110 | { | |
111 | unsigned long ready; | |
112 | long i; | |
113 | ||
114 | switch (_NSIG_WORDS) { | |
115 | default: | |
116 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
117 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
118 | break; | |
119 | ||
120 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
121 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
122 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
123 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
124 | break; | |
125 | ||
126 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
127 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
128 | break; | |
129 | ||
130 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
131 | } | |
132 | return ready != 0; | |
133 | } | |
134 | ||
135 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
136 | ||
7bb44ade | 137 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 138 | { |
3759a0d9 | 139 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 140 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 141 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 142 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
143 | return 1; |
144 | } | |
b74d0deb RM |
145 | /* |
146 | * We must never clear the flag in another thread, or in current | |
147 | * when it's possible the current syscall is returning -ERESTART*. | |
148 | * So we don't clear it here, and only callers who know they should do. | |
149 | */ | |
7bb44ade RM |
150 | return 0; |
151 | } | |
152 | ||
153 | /* | |
154 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
155 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
156 | */ | |
157 | void recalc_sigpending_and_wake(struct task_struct *t) | |
158 | { | |
159 | if (recalc_sigpending_tsk(t)) | |
160 | signal_wake_up(t, 0); | |
1da177e4 LT |
161 | } |
162 | ||
163 | void recalc_sigpending(void) | |
164 | { | |
dd1d6772 | 165 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
166 | clear_thread_flag(TIF_SIGPENDING); |
167 | ||
1da177e4 LT |
168 | } |
169 | ||
170 | /* Given the mask, find the first available signal that should be serviced. */ | |
171 | ||
a27341cd LT |
172 | #define SYNCHRONOUS_MASK \ |
173 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 174 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 175 | |
fba2afaa | 176 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
177 | { |
178 | unsigned long i, *s, *m, x; | |
179 | int sig = 0; | |
f84d49b2 | 180 | |
1da177e4 LT |
181 | s = pending->signal.sig; |
182 | m = mask->sig; | |
a27341cd LT |
183 | |
184 | /* | |
185 | * Handle the first word specially: it contains the | |
186 | * synchronous signals that need to be dequeued first. | |
187 | */ | |
188 | x = *s &~ *m; | |
189 | if (x) { | |
190 | if (x & SYNCHRONOUS_MASK) | |
191 | x &= SYNCHRONOUS_MASK; | |
192 | sig = ffz(~x) + 1; | |
193 | return sig; | |
194 | } | |
195 | ||
1da177e4 LT |
196 | switch (_NSIG_WORDS) { |
197 | default: | |
a27341cd LT |
198 | for (i = 1; i < _NSIG_WORDS; ++i) { |
199 | x = *++s &~ *++m; | |
200 | if (!x) | |
201 | continue; | |
202 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
203 | break; | |
204 | } | |
1da177e4 LT |
205 | break; |
206 | ||
a27341cd LT |
207 | case 2: |
208 | x = s[1] &~ m[1]; | |
209 | if (!x) | |
1da177e4 | 210 | break; |
a27341cd | 211 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
212 | break; |
213 | ||
a27341cd LT |
214 | case 1: |
215 | /* Nothing to do */ | |
1da177e4 LT |
216 | break; |
217 | } | |
f84d49b2 | 218 | |
1da177e4 LT |
219 | return sig; |
220 | } | |
221 | ||
f84d49b2 NO |
222 | static inline void print_dropped_signal(int sig) |
223 | { | |
224 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
225 | ||
226 | if (!print_fatal_signals) | |
227 | return; | |
228 | ||
229 | if (!__ratelimit(&ratelimit_state)) | |
230 | return; | |
231 | ||
747800ef | 232 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
f84d49b2 NO |
233 | current->comm, current->pid, sig); |
234 | } | |
235 | ||
d79fdd6d | 236 | /** |
7dd3db54 | 237 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 238 | * @task: target task |
7dd3db54 | 239 | * @mask: pending bits to set |
d79fdd6d | 240 | * |
7dd3db54 TH |
241 | * Clear @mask from @task->jobctl. @mask must be subset of |
242 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
243 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
244 | * cleared. If @task is already being killed or exiting, this function | |
245 | * becomes noop. | |
246 | * | |
247 | * CONTEXT: | |
248 | * Must be called with @task->sighand->siglock held. | |
249 | * | |
250 | * RETURNS: | |
251 | * %true if @mask is set, %false if made noop because @task was dying. | |
252 | */ | |
b76808e6 | 253 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
7dd3db54 TH |
254 | { |
255 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
256 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
257 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
258 | ||
259 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
260 | return false; | |
261 | ||
262 | if (mask & JOBCTL_STOP_SIGMASK) | |
263 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
264 | ||
265 | task->jobctl |= mask; | |
266 | return true; | |
267 | } | |
268 | ||
d79fdd6d | 269 | /** |
a8f072c1 | 270 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
271 | * @task: target task |
272 | * | |
a8f072c1 TH |
273 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
274 | * Clear it and wake up the ptracer. Note that we don't need any further | |
275 | * locking. @task->siglock guarantees that @task->parent points to the | |
276 | * ptracer. | |
d79fdd6d TH |
277 | * |
278 | * CONTEXT: | |
279 | * Must be called with @task->sighand->siglock held. | |
280 | */ | |
73ddff2b | 281 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 282 | { |
a8f072c1 TH |
283 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
284 | task->jobctl &= ~JOBCTL_TRAPPING; | |
650226bd | 285 | smp_mb(); /* advised by wake_up_bit() */ |
62c124ff | 286 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
287 | } |
288 | } | |
289 | ||
e5c1902e | 290 | /** |
3759a0d9 | 291 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 292 | * @task: target task |
3759a0d9 | 293 | * @mask: pending bits to clear |
e5c1902e | 294 | * |
3759a0d9 TH |
295 | * Clear @mask from @task->jobctl. @mask must be subset of |
296 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
297 | * STOP bits are cleared together. | |
e5c1902e | 298 | * |
6dfca329 TH |
299 | * If clearing of @mask leaves no stop or trap pending, this function calls |
300 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
301 | * |
302 | * CONTEXT: | |
303 | * Must be called with @task->sighand->siglock held. | |
304 | */ | |
b76808e6 | 305 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
e5c1902e | 306 | { |
3759a0d9 TH |
307 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
308 | ||
309 | if (mask & JOBCTL_STOP_PENDING) | |
310 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
311 | ||
312 | task->jobctl &= ~mask; | |
6dfca329 TH |
313 | |
314 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
315 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
316 | } |
317 | ||
318 | /** | |
319 | * task_participate_group_stop - participate in a group stop | |
320 | * @task: task participating in a group stop | |
321 | * | |
a8f072c1 | 322 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 323 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 324 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 325 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
326 | * |
327 | * CONTEXT: | |
328 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
329 | * |
330 | * RETURNS: | |
331 | * %true if group stop completion should be notified to the parent, %false | |
332 | * otherwise. | |
e5c1902e TH |
333 | */ |
334 | static bool task_participate_group_stop(struct task_struct *task) | |
335 | { | |
336 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 337 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 338 | |
a8f072c1 | 339 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 340 | |
3759a0d9 | 341 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
342 | |
343 | if (!consume) | |
344 | return false; | |
345 | ||
346 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
347 | sig->group_stop_count--; | |
348 | ||
244056f9 TH |
349 | /* |
350 | * Tell the caller to notify completion iff we are entering into a | |
351 | * fresh group stop. Read comment in do_signal_stop() for details. | |
352 | */ | |
353 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
2d39b3cd | 354 | signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
e5c1902e TH |
355 | return true; |
356 | } | |
357 | return false; | |
358 | } | |
359 | ||
c69e8d9c DH |
360 | /* |
361 | * allocate a new signal queue record | |
362 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 363 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 364 | */ |
f84d49b2 NO |
365 | static struct sigqueue * |
366 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
367 | { |
368 | struct sigqueue *q = NULL; | |
10b1fbdb | 369 | struct user_struct *user; |
1da177e4 | 370 | |
10b1fbdb | 371 | /* |
7cf7db8d TG |
372 | * Protect access to @t credentials. This can go away when all |
373 | * callers hold rcu read lock. | |
10b1fbdb | 374 | */ |
7cf7db8d | 375 | rcu_read_lock(); |
d84f4f99 | 376 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 377 | atomic_inc(&user->sigpending); |
7cf7db8d | 378 | rcu_read_unlock(); |
f84d49b2 | 379 | |
1da177e4 | 380 | if (override_rlimit || |
10b1fbdb | 381 | atomic_read(&user->sigpending) <= |
78d7d407 | 382 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 383 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
384 | } else { |
385 | print_dropped_signal(sig); | |
386 | } | |
387 | ||
1da177e4 | 388 | if (unlikely(q == NULL)) { |
10b1fbdb | 389 | atomic_dec(&user->sigpending); |
d84f4f99 | 390 | free_uid(user); |
1da177e4 LT |
391 | } else { |
392 | INIT_LIST_HEAD(&q->list); | |
393 | q->flags = 0; | |
d84f4f99 | 394 | q->user = user; |
1da177e4 | 395 | } |
d84f4f99 DH |
396 | |
397 | return q; | |
1da177e4 LT |
398 | } |
399 | ||
514a01b8 | 400 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
401 | { |
402 | if (q->flags & SIGQUEUE_PREALLOC) | |
403 | return; | |
404 | atomic_dec(&q->user->sigpending); | |
405 | free_uid(q->user); | |
406 | kmem_cache_free(sigqueue_cachep, q); | |
407 | } | |
408 | ||
6a14c5c9 | 409 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
410 | { |
411 | struct sigqueue *q; | |
412 | ||
413 | sigemptyset(&queue->signal); | |
414 | while (!list_empty(&queue->list)) { | |
415 | q = list_entry(queue->list.next, struct sigqueue , list); | |
416 | list_del_init(&q->list); | |
417 | __sigqueue_free(q); | |
418 | } | |
419 | } | |
420 | ||
421 | /* | |
9e7c8f8c | 422 | * Flush all pending signals for this kthread. |
1da177e4 | 423 | */ |
c81addc9 | 424 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
425 | { |
426 | unsigned long flags; | |
427 | ||
428 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
9e7c8f8c ON |
429 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
430 | flush_sigqueue(&t->pending); | |
431 | flush_sigqueue(&t->signal->shared_pending); | |
1da177e4 LT |
432 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
433 | } | |
434 | ||
baa73d9e | 435 | #ifdef CONFIG_POSIX_TIMERS |
cbaffba1 ON |
436 | static void __flush_itimer_signals(struct sigpending *pending) |
437 | { | |
438 | sigset_t signal, retain; | |
439 | struct sigqueue *q, *n; | |
440 | ||
441 | signal = pending->signal; | |
442 | sigemptyset(&retain); | |
443 | ||
444 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
445 | int sig = q->info.si_signo; | |
446 | ||
447 | if (likely(q->info.si_code != SI_TIMER)) { | |
448 | sigaddset(&retain, sig); | |
449 | } else { | |
450 | sigdelset(&signal, sig); | |
451 | list_del_init(&q->list); | |
452 | __sigqueue_free(q); | |
453 | } | |
454 | } | |
455 | ||
456 | sigorsets(&pending->signal, &signal, &retain); | |
457 | } | |
458 | ||
459 | void flush_itimer_signals(void) | |
460 | { | |
461 | struct task_struct *tsk = current; | |
462 | unsigned long flags; | |
463 | ||
464 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
465 | __flush_itimer_signals(&tsk->pending); | |
466 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
467 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
468 | } | |
baa73d9e | 469 | #endif |
cbaffba1 | 470 | |
10ab825b ON |
471 | void ignore_signals(struct task_struct *t) |
472 | { | |
473 | int i; | |
474 | ||
475 | for (i = 0; i < _NSIG; ++i) | |
476 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
477 | ||
478 | flush_signals(t); | |
479 | } | |
480 | ||
1da177e4 LT |
481 | /* |
482 | * Flush all handlers for a task. | |
483 | */ | |
484 | ||
485 | void | |
486 | flush_signal_handlers(struct task_struct *t, int force_default) | |
487 | { | |
488 | int i; | |
489 | struct k_sigaction *ka = &t->sighand->action[0]; | |
490 | for (i = _NSIG ; i != 0 ; i--) { | |
491 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
492 | ka->sa.sa_handler = SIG_DFL; | |
493 | ka->sa.sa_flags = 0; | |
522cff14 | 494 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
495 | ka->sa.sa_restorer = NULL; |
496 | #endif | |
1da177e4 LT |
497 | sigemptyset(&ka->sa.sa_mask); |
498 | ka++; | |
499 | } | |
500 | } | |
501 | ||
abd4f750 MAS |
502 | int unhandled_signal(struct task_struct *tsk, int sig) |
503 | { | |
445a91d2 | 504 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 505 | if (is_global_init(tsk)) |
abd4f750 | 506 | return 1; |
445a91d2 | 507 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 508 | return 0; |
a288eecc TH |
509 | /* if ptraced, let the tracer determine */ |
510 | return !tsk->ptrace; | |
abd4f750 MAS |
511 | } |
512 | ||
57db7e4a EB |
513 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info, |
514 | bool *resched_timer) | |
1da177e4 LT |
515 | { |
516 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 517 | |
1da177e4 LT |
518 | /* |
519 | * Collect the siginfo appropriate to this signal. Check if | |
520 | * there is another siginfo for the same signal. | |
521 | */ | |
522 | list_for_each_entry(q, &list->list, list) { | |
523 | if (q->info.si_signo == sig) { | |
d4434207 ON |
524 | if (first) |
525 | goto still_pending; | |
1da177e4 LT |
526 | first = q; |
527 | } | |
528 | } | |
d4434207 ON |
529 | |
530 | sigdelset(&list->signal, sig); | |
531 | ||
1da177e4 | 532 | if (first) { |
d4434207 | 533 | still_pending: |
1da177e4 LT |
534 | list_del_init(&first->list); |
535 | copy_siginfo(info, &first->info); | |
57db7e4a EB |
536 | |
537 | *resched_timer = | |
538 | (first->flags & SIGQUEUE_PREALLOC) && | |
539 | (info->si_code == SI_TIMER) && | |
540 | (info->si_sys_private); | |
541 | ||
1da177e4 | 542 | __sigqueue_free(first); |
1da177e4 | 543 | } else { |
5aba085e RD |
544 | /* |
545 | * Ok, it wasn't in the queue. This must be | |
546 | * a fast-pathed signal or we must have been | |
547 | * out of queue space. So zero out the info. | |
1da177e4 | 548 | */ |
1da177e4 LT |
549 | info->si_signo = sig; |
550 | info->si_errno = 0; | |
7486e5d9 | 551 | info->si_code = SI_USER; |
1da177e4 LT |
552 | info->si_pid = 0; |
553 | info->si_uid = 0; | |
554 | } | |
1da177e4 LT |
555 | } |
556 | ||
557 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
57db7e4a | 558 | siginfo_t *info, bool *resched_timer) |
1da177e4 | 559 | { |
27d91e07 | 560 | int sig = next_signal(pending, mask); |
1da177e4 | 561 | |
2e01fabe | 562 | if (sig) |
57db7e4a | 563 | collect_signal(sig, pending, info, resched_timer); |
1da177e4 LT |
564 | return sig; |
565 | } | |
566 | ||
567 | /* | |
5aba085e | 568 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
569 | * expected to free it. |
570 | * | |
571 | * All callers have to hold the siglock. | |
572 | */ | |
573 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
574 | { | |
57db7e4a | 575 | bool resched_timer = false; |
c5363d03 | 576 | int signr; |
caec4e8d BH |
577 | |
578 | /* We only dequeue private signals from ourselves, we don't let | |
579 | * signalfd steal them | |
580 | */ | |
57db7e4a | 581 | signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer); |
8bfd9a7a | 582 | if (!signr) { |
1da177e4 | 583 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
57db7e4a | 584 | mask, info, &resched_timer); |
baa73d9e | 585 | #ifdef CONFIG_POSIX_TIMERS |
8bfd9a7a TG |
586 | /* |
587 | * itimer signal ? | |
588 | * | |
589 | * itimers are process shared and we restart periodic | |
590 | * itimers in the signal delivery path to prevent DoS | |
591 | * attacks in the high resolution timer case. This is | |
5aba085e | 592 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
593 | * itimers, as the SIGALRM is a legacy signal and only |
594 | * queued once. Changing the restart behaviour to | |
595 | * restart the timer in the signal dequeue path is | |
596 | * reducing the timer noise on heavy loaded !highres | |
597 | * systems too. | |
598 | */ | |
599 | if (unlikely(signr == SIGALRM)) { | |
600 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
601 | ||
602 | if (!hrtimer_is_queued(tmr) && | |
2456e855 | 603 | tsk->signal->it_real_incr != 0) { |
8bfd9a7a TG |
604 | hrtimer_forward(tmr, tmr->base->get_time(), |
605 | tsk->signal->it_real_incr); | |
606 | hrtimer_restart(tmr); | |
607 | } | |
608 | } | |
baa73d9e | 609 | #endif |
8bfd9a7a | 610 | } |
c5363d03 | 611 | |
b8fceee1 | 612 | recalc_sigpending(); |
c5363d03 PE |
613 | if (!signr) |
614 | return 0; | |
615 | ||
616 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
617 | /* |
618 | * Set a marker that we have dequeued a stop signal. Our | |
619 | * caller might release the siglock and then the pending | |
620 | * stop signal it is about to process is no longer in the | |
621 | * pending bitmasks, but must still be cleared by a SIGCONT | |
622 | * (and overruled by a SIGKILL). So those cases clear this | |
623 | * shared flag after we've set it. Note that this flag may | |
624 | * remain set after the signal we return is ignored or | |
625 | * handled. That doesn't matter because its only purpose | |
626 | * is to alert stop-signal processing code when another | |
627 | * processor has come along and cleared the flag. | |
628 | */ | |
a8f072c1 | 629 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 630 | } |
baa73d9e | 631 | #ifdef CONFIG_POSIX_TIMERS |
57db7e4a | 632 | if (resched_timer) { |
1da177e4 LT |
633 | /* |
634 | * Release the siglock to ensure proper locking order | |
635 | * of timer locks outside of siglocks. Note, we leave | |
636 | * irqs disabled here, since the posix-timers code is | |
637 | * about to disable them again anyway. | |
638 | */ | |
639 | spin_unlock(&tsk->sighand->siglock); | |
640 | do_schedule_next_timer(info); | |
641 | spin_lock(&tsk->sighand->siglock); | |
642 | } | |
baa73d9e | 643 | #endif |
1da177e4 LT |
644 | return signr; |
645 | } | |
646 | ||
647 | /* | |
648 | * Tell a process that it has a new active signal.. | |
649 | * | |
650 | * NOTE! we rely on the previous spin_lock to | |
651 | * lock interrupts for us! We can only be called with | |
652 | * "siglock" held, and the local interrupt must | |
653 | * have been disabled when that got acquired! | |
654 | * | |
655 | * No need to set need_resched since signal event passing | |
656 | * goes through ->blocked | |
657 | */ | |
910ffdb1 | 658 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 659 | { |
1da177e4 | 660 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 661 | /* |
910ffdb1 | 662 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 663 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
664 | * executing another processor and just now entering stopped state. |
665 | * By using wake_up_state, we ensure the process will wake up and | |
666 | * handle its death signal. | |
667 | */ | |
910ffdb1 | 668 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
669 | kick_process(t); |
670 | } | |
671 | ||
71fabd5e GA |
672 | /* |
673 | * Remove signals in mask from the pending set and queue. | |
674 | * Returns 1 if any signals were found. | |
675 | * | |
676 | * All callers must be holding the siglock. | |
71fabd5e | 677 | */ |
c09c1441 | 678 | static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
71fabd5e GA |
679 | { |
680 | struct sigqueue *q, *n; | |
681 | sigset_t m; | |
682 | ||
683 | sigandsets(&m, mask, &s->signal); | |
684 | if (sigisemptyset(&m)) | |
685 | return 0; | |
686 | ||
702a5073 | 687 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
688 | list_for_each_entry_safe(q, n, &s->list, list) { |
689 | if (sigismember(mask, q->info.si_signo)) { | |
690 | list_del_init(&q->list); | |
691 | __sigqueue_free(q); | |
692 | } | |
693 | } | |
694 | return 1; | |
695 | } | |
1da177e4 | 696 | |
614c517d ON |
697 | static inline int is_si_special(const struct siginfo *info) |
698 | { | |
699 | return info <= SEND_SIG_FORCED; | |
700 | } | |
701 | ||
702 | static inline bool si_fromuser(const struct siginfo *info) | |
703 | { | |
704 | return info == SEND_SIG_NOINFO || | |
705 | (!is_si_special(info) && SI_FROMUSER(info)); | |
706 | } | |
707 | ||
39fd3393 SH |
708 | /* |
709 | * called with RCU read lock from check_kill_permission() | |
710 | */ | |
711 | static int kill_ok_by_cred(struct task_struct *t) | |
712 | { | |
713 | const struct cred *cred = current_cred(); | |
714 | const struct cred *tcred = __task_cred(t); | |
715 | ||
5af66203 EB |
716 | if (uid_eq(cred->euid, tcred->suid) || |
717 | uid_eq(cred->euid, tcred->uid) || | |
718 | uid_eq(cred->uid, tcred->suid) || | |
719 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
720 | return 1; |
721 | ||
c4a4d603 | 722 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
723 | return 1; |
724 | ||
725 | return 0; | |
726 | } | |
727 | ||
1da177e4 LT |
728 | /* |
729 | * Bad permissions for sending the signal | |
694f690d | 730 | * - the caller must hold the RCU read lock |
1da177e4 LT |
731 | */ |
732 | static int check_kill_permission(int sig, struct siginfo *info, | |
733 | struct task_struct *t) | |
734 | { | |
2e2ba22e | 735 | struct pid *sid; |
3b5e9e53 ON |
736 | int error; |
737 | ||
7ed20e1a | 738 | if (!valid_signal(sig)) |
3b5e9e53 ON |
739 | return -EINVAL; |
740 | ||
614c517d | 741 | if (!si_fromuser(info)) |
3b5e9e53 | 742 | return 0; |
e54dc243 | 743 | |
3b5e9e53 ON |
744 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
745 | if (error) | |
1da177e4 | 746 | return error; |
3b5e9e53 | 747 | |
065add39 | 748 | if (!same_thread_group(current, t) && |
39fd3393 | 749 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
750 | switch (sig) { |
751 | case SIGCONT: | |
2e2ba22e | 752 | sid = task_session(t); |
2e2ba22e ON |
753 | /* |
754 | * We don't return the error if sid == NULL. The | |
755 | * task was unhashed, the caller must notice this. | |
756 | */ | |
757 | if (!sid || sid == task_session(current)) | |
758 | break; | |
759 | default: | |
760 | return -EPERM; | |
761 | } | |
762 | } | |
c2f0c7c3 | 763 | |
e54dc243 | 764 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
765 | } |
766 | ||
fb1d910c TH |
767 | /** |
768 | * ptrace_trap_notify - schedule trap to notify ptracer | |
769 | * @t: tracee wanting to notify tracer | |
770 | * | |
771 | * This function schedules sticky ptrace trap which is cleared on the next | |
772 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
773 | * ptracer. | |
774 | * | |
544b2c91 TH |
775 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
776 | * ptracer is listening for events, tracee is woken up so that it can | |
777 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
778 | * eventually taken without returning to userland after the existing traps | |
779 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
780 | * |
781 | * CONTEXT: | |
782 | * Must be called with @task->sighand->siglock held. | |
783 | */ | |
784 | static void ptrace_trap_notify(struct task_struct *t) | |
785 | { | |
786 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
787 | assert_spin_locked(&t->sighand->siglock); | |
788 | ||
789 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 790 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
791 | } |
792 | ||
1da177e4 | 793 | /* |
7e695a5e ON |
794 | * Handle magic process-wide effects of stop/continue signals. Unlike |
795 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
796 | * time regardless of blocking, ignoring, or handling. This does the |
797 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
798 | * signals. The process stop is done as a signal action for SIG_DFL. |
799 | * | |
800 | * Returns true if the signal should be actually delivered, otherwise | |
801 | * it should be dropped. | |
1da177e4 | 802 | */ |
403bad72 | 803 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 804 | { |
ad16a460 | 805 | struct signal_struct *signal = p->signal; |
1da177e4 | 806 | struct task_struct *t; |
9490592f | 807 | sigset_t flush; |
1da177e4 | 808 | |
403bad72 | 809 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { |
5fa534c9 | 810 | if (!(signal->flags & SIGNAL_GROUP_EXIT)) |
403bad72 | 811 | return sig == SIGKILL; |
1da177e4 | 812 | /* |
7e695a5e | 813 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 814 | */ |
7e695a5e | 815 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
816 | /* |
817 | * This is a stop signal. Remove SIGCONT from all queues. | |
818 | */ | |
9490592f | 819 | siginitset(&flush, sigmask(SIGCONT)); |
c09c1441 | 820 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 821 | for_each_thread(p, t) |
c09c1441 | 822 | flush_sigqueue_mask(&flush, &t->pending); |
1da177e4 | 823 | } else if (sig == SIGCONT) { |
fc321d2e | 824 | unsigned int why; |
1da177e4 | 825 | /* |
1deac632 | 826 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 827 | */ |
9490592f | 828 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
c09c1441 | 829 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 830 | for_each_thread(p, t) { |
c09c1441 | 831 | flush_sigqueue_mask(&flush, &t->pending); |
3759a0d9 | 832 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
fb1d910c TH |
833 | if (likely(!(t->ptrace & PT_SEIZED))) |
834 | wake_up_state(t, __TASK_STOPPED); | |
835 | else | |
836 | ptrace_trap_notify(t); | |
9490592f | 837 | } |
1da177e4 | 838 | |
fc321d2e ON |
839 | /* |
840 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
841 | * | |
842 | * If we were in the middle of a group stop, we pretend it | |
843 | * was already finished, and then continued. Since SIGCHLD | |
844 | * doesn't queue we report only CLD_STOPPED, as if the next | |
845 | * CLD_CONTINUED was dropped. | |
846 | */ | |
847 | why = 0; | |
ad16a460 | 848 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 849 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 850 | else if (signal->group_stop_count) |
fc321d2e ON |
851 | why |= SIGNAL_CLD_STOPPED; |
852 | ||
853 | if (why) { | |
021e1ae3 | 854 | /* |
ae6d2ed7 | 855 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
856 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
857 | * notify its parent. See get_signal_to_deliver(). | |
858 | */ | |
2d39b3cd | 859 | signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
ad16a460 ON |
860 | signal->group_stop_count = 0; |
861 | signal->group_exit_code = 0; | |
1da177e4 | 862 | } |
1da177e4 | 863 | } |
7e695a5e | 864 | |
def8cf72 | 865 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
866 | } |
867 | ||
71f11dc0 ON |
868 | /* |
869 | * Test if P wants to take SIG. After we've checked all threads with this, | |
870 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
871 | * blocking SIG were ruled out because they are not running and already | |
872 | * have pending signals. Such threads will dequeue from the shared queue | |
873 | * as soon as they're available, so putting the signal on the shared queue | |
874 | * will be equivalent to sending it to one such thread. | |
875 | */ | |
876 | static inline int wants_signal(int sig, struct task_struct *p) | |
877 | { | |
878 | if (sigismember(&p->blocked, sig)) | |
879 | return 0; | |
880 | if (p->flags & PF_EXITING) | |
881 | return 0; | |
882 | if (sig == SIGKILL) | |
883 | return 1; | |
884 | if (task_is_stopped_or_traced(p)) | |
885 | return 0; | |
886 | return task_curr(p) || !signal_pending(p); | |
887 | } | |
888 | ||
5fcd835b | 889 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
890 | { |
891 | struct signal_struct *signal = p->signal; | |
892 | struct task_struct *t; | |
893 | ||
894 | /* | |
895 | * Now find a thread we can wake up to take the signal off the queue. | |
896 | * | |
897 | * If the main thread wants the signal, it gets first crack. | |
898 | * Probably the least surprising to the average bear. | |
899 | */ | |
900 | if (wants_signal(sig, p)) | |
901 | t = p; | |
5fcd835b | 902 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
903 | /* |
904 | * There is just one thread and it does not need to be woken. | |
905 | * It will dequeue unblocked signals before it runs again. | |
906 | */ | |
907 | return; | |
908 | else { | |
909 | /* | |
910 | * Otherwise try to find a suitable thread. | |
911 | */ | |
912 | t = signal->curr_target; | |
913 | while (!wants_signal(sig, t)) { | |
914 | t = next_thread(t); | |
915 | if (t == signal->curr_target) | |
916 | /* | |
917 | * No thread needs to be woken. | |
918 | * Any eligible threads will see | |
919 | * the signal in the queue soon. | |
920 | */ | |
921 | return; | |
922 | } | |
923 | signal->curr_target = t; | |
924 | } | |
925 | ||
926 | /* | |
927 | * Found a killable thread. If the signal will be fatal, | |
928 | * then start taking the whole group down immediately. | |
929 | */ | |
fae5fa44 ON |
930 | if (sig_fatal(p, sig) && |
931 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && | |
71f11dc0 | 932 | !sigismember(&t->real_blocked, sig) && |
a288eecc | 933 | (sig == SIGKILL || !t->ptrace)) { |
71f11dc0 ON |
934 | /* |
935 | * This signal will be fatal to the whole group. | |
936 | */ | |
937 | if (!sig_kernel_coredump(sig)) { | |
938 | /* | |
939 | * Start a group exit and wake everybody up. | |
940 | * This way we don't have other threads | |
941 | * running and doing things after a slower | |
942 | * thread has the fatal signal pending. | |
943 | */ | |
944 | signal->flags = SIGNAL_GROUP_EXIT; | |
945 | signal->group_exit_code = sig; | |
946 | signal->group_stop_count = 0; | |
947 | t = p; | |
948 | do { | |
6dfca329 | 949 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
950 | sigaddset(&t->pending.signal, SIGKILL); |
951 | signal_wake_up(t, 1); | |
952 | } while_each_thread(p, t); | |
953 | return; | |
954 | } | |
955 | } | |
956 | ||
957 | /* | |
958 | * The signal is already in the shared-pending queue. | |
959 | * Tell the chosen thread to wake up and dequeue it. | |
960 | */ | |
961 | signal_wake_up(t, sig == SIGKILL); | |
962 | return; | |
963 | } | |
964 | ||
af7fff9c PE |
965 | static inline int legacy_queue(struct sigpending *signals, int sig) |
966 | { | |
967 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
968 | } | |
969 | ||
6b550f94 SH |
970 | #ifdef CONFIG_USER_NS |
971 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
972 | { | |
973 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
974 | return; | |
975 | ||
976 | if (SI_FROMKERNEL(info)) | |
977 | return; | |
978 | ||
078de5f7 EB |
979 | rcu_read_lock(); |
980 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
981 | make_kuid(current_user_ns(), info->si_uid)); | |
982 | rcu_read_unlock(); | |
6b550f94 SH |
983 | } |
984 | #else | |
985 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
986 | { | |
987 | return; | |
988 | } | |
989 | #endif | |
990 | ||
7978b567 SB |
991 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
992 | int group, int from_ancestor_ns) | |
1da177e4 | 993 | { |
2ca3515a | 994 | struct sigpending *pending; |
6e65acba | 995 | struct sigqueue *q; |
7a0aeb14 | 996 | int override_rlimit; |
6c303d3a | 997 | int ret = 0, result; |
0a16b607 | 998 | |
6e65acba | 999 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1000 | |
6c303d3a | 1001 | result = TRACE_SIGNAL_IGNORED; |
629d362b ON |
1002 | if (!prepare_signal(sig, t, |
1003 | from_ancestor_ns || (info == SEND_SIG_FORCED))) | |
6c303d3a | 1004 | goto ret; |
2ca3515a ON |
1005 | |
1006 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
1007 | /* |
1008 | * Short-circuit ignored signals and support queuing | |
1009 | * exactly one non-rt signal, so that we can get more | |
1010 | * detailed information about the cause of the signal. | |
1011 | */ | |
6c303d3a | 1012 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1013 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1014 | goto ret; |
1015 | ||
1016 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1017 | /* |
1018 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1019 | * or SIGKILL. | |
1020 | */ | |
b67a1b9e | 1021 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1022 | goto out_set; |
1023 | ||
5aba085e RD |
1024 | /* |
1025 | * Real-time signals must be queued if sent by sigqueue, or | |
1026 | * some other real-time mechanism. It is implementation | |
1027 | * defined whether kill() does so. We attempt to do so, on | |
1028 | * the principle of least surprise, but since kill is not | |
1029 | * allowed to fail with EAGAIN when low on memory we just | |
1030 | * make sure at least one signal gets delivered and don't | |
1031 | * pass on the info struct. | |
1032 | */ | |
7a0aeb14 VN |
1033 | if (sig < SIGRTMIN) |
1034 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1035 | else | |
1036 | override_rlimit = 0; | |
1037 | ||
f84d49b2 | 1038 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, |
7a0aeb14 | 1039 | override_rlimit); |
1da177e4 | 1040 | if (q) { |
2ca3515a | 1041 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1042 | switch ((unsigned long) info) { |
b67a1b9e | 1043 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1044 | q->info.si_signo = sig; |
1045 | q->info.si_errno = 0; | |
1046 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1047 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1048 | task_active_pid_ns(t)); |
078de5f7 | 1049 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1050 | break; |
b67a1b9e | 1051 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1052 | q->info.si_signo = sig; |
1053 | q->info.si_errno = 0; | |
1054 | q->info.si_code = SI_KERNEL; | |
1055 | q->info.si_pid = 0; | |
1056 | q->info.si_uid = 0; | |
1057 | break; | |
1058 | default: | |
1059 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1060 | if (from_ancestor_ns) |
1061 | q->info.si_pid = 0; | |
1da177e4 LT |
1062 | break; |
1063 | } | |
6b550f94 SH |
1064 | |
1065 | userns_fixup_signal_uid(&q->info, t); | |
1066 | ||
621d3121 | 1067 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1068 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1069 | /* | |
1070 | * Queue overflow, abort. We may abort if the | |
1071 | * signal was rt and sent by user using something | |
1072 | * other than kill(). | |
1073 | */ | |
6c303d3a ON |
1074 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1075 | ret = -EAGAIN; | |
1076 | goto ret; | |
ba005e1f MH |
1077 | } else { |
1078 | /* | |
1079 | * This is a silent loss of information. We still | |
1080 | * send the signal, but the *info bits are lost. | |
1081 | */ | |
6c303d3a | 1082 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1083 | } |
1da177e4 LT |
1084 | } |
1085 | ||
1086 | out_set: | |
53c30337 | 1087 | signalfd_notify(t, sig); |
2ca3515a | 1088 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1089 | complete_signal(sig, t, group); |
6c303d3a ON |
1090 | ret: |
1091 | trace_signal_generate(sig, info, t, group, result); | |
1092 | return ret; | |
1da177e4 LT |
1093 | } |
1094 | ||
7978b567 SB |
1095 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1096 | int group) | |
1097 | { | |
921cf9f6 SB |
1098 | int from_ancestor_ns = 0; |
1099 | ||
1100 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1101 | from_ancestor_ns = si_fromuser(info) && |
1102 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1103 | #endif |
1104 | ||
1105 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1106 | } |
1107 | ||
4aaefee5 | 1108 | static void print_fatal_signal(int signr) |
45807a1d | 1109 | { |
4aaefee5 | 1110 | struct pt_regs *regs = signal_pt_regs(); |
747800ef | 1111 | pr_info("potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1112 | |
ca5cd877 | 1113 | #if defined(__i386__) && !defined(__arch_um__) |
747800ef | 1114 | pr_info("code at %08lx: ", regs->ip); |
45807a1d IM |
1115 | { |
1116 | int i; | |
1117 | for (i = 0; i < 16; i++) { | |
1118 | unsigned char insn; | |
1119 | ||
b45c6e76 AK |
1120 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1121 | break; | |
747800ef | 1122 | pr_cont("%02x ", insn); |
45807a1d IM |
1123 | } |
1124 | } | |
747800ef | 1125 | pr_cont("\n"); |
45807a1d | 1126 | #endif |
3a9f84d3 | 1127 | preempt_disable(); |
45807a1d | 1128 | show_regs(regs); |
3a9f84d3 | 1129 | preempt_enable(); |
45807a1d IM |
1130 | } |
1131 | ||
1132 | static int __init setup_print_fatal_signals(char *str) | |
1133 | { | |
1134 | get_option (&str, &print_fatal_signals); | |
1135 | ||
1136 | return 1; | |
1137 | } | |
1138 | ||
1139 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1140 | |
4cd4b6d4 PE |
1141 | int |
1142 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1143 | { | |
1144 | return send_signal(sig, info, p, 1); | |
1145 | } | |
1146 | ||
1da177e4 LT |
1147 | static int |
1148 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1149 | { | |
4cd4b6d4 | 1150 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1151 | } |
1152 | ||
4a30debf ON |
1153 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1154 | bool group) | |
1155 | { | |
1156 | unsigned long flags; | |
1157 | int ret = -ESRCH; | |
1158 | ||
1159 | if (lock_task_sighand(p, &flags)) { | |
1160 | ret = send_signal(sig, info, p, group); | |
1161 | unlock_task_sighand(p, &flags); | |
1162 | } | |
1163 | ||
1164 | return ret; | |
1165 | } | |
1166 | ||
1da177e4 LT |
1167 | /* |
1168 | * Force a signal that the process can't ignore: if necessary | |
1169 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1170 | * |
1171 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1172 | * since we do not want to have a signal handler that was blocked | |
1173 | * be invoked when user space had explicitly blocked it. | |
1174 | * | |
80fe728d ON |
1175 | * We don't want to have recursive SIGSEGV's etc, for example, |
1176 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1177 | */ |
1da177e4 LT |
1178 | int |
1179 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1180 | { | |
1181 | unsigned long int flags; | |
ae74c3b6 LT |
1182 | int ret, blocked, ignored; |
1183 | struct k_sigaction *action; | |
1da177e4 LT |
1184 | |
1185 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1186 | action = &t->sighand->action[sig-1]; |
1187 | ignored = action->sa.sa_handler == SIG_IGN; | |
1188 | blocked = sigismember(&t->blocked, sig); | |
1189 | if (blocked || ignored) { | |
1190 | action->sa.sa_handler = SIG_DFL; | |
1191 | if (blocked) { | |
1192 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1193 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1194 | } |
1da177e4 | 1195 | } |
80fe728d ON |
1196 | if (action->sa.sa_handler == SIG_DFL) |
1197 | t->signal->flags &= ~SIGNAL_UNKILLABLE; | |
1da177e4 LT |
1198 | ret = specific_send_sig_info(sig, info, t); |
1199 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1200 | ||
1201 | return ret; | |
1202 | } | |
1203 | ||
1da177e4 LT |
1204 | /* |
1205 | * Nuke all other threads in the group. | |
1206 | */ | |
09faef11 | 1207 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1208 | { |
09faef11 ON |
1209 | struct task_struct *t = p; |
1210 | int count = 0; | |
1da177e4 | 1211 | |
1da177e4 LT |
1212 | p->signal->group_stop_count = 0; |
1213 | ||
09faef11 | 1214 | while_each_thread(p, t) { |
6dfca329 | 1215 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1216 | count++; |
1217 | ||
1218 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1219 | if (t->exit_state) |
1220 | continue; | |
1da177e4 | 1221 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1222 | signal_wake_up(t, 1); |
1223 | } | |
09faef11 ON |
1224 | |
1225 | return count; | |
1da177e4 LT |
1226 | } |
1227 | ||
b8ed374e NK |
1228 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1229 | unsigned long *flags) | |
f63ee72e ON |
1230 | { |
1231 | struct sighand_struct *sighand; | |
1232 | ||
1233 | for (;;) { | |
c41247e1 PM |
1234 | /* |
1235 | * Disable interrupts early to avoid deadlocks. | |
1236 | * See rcu_read_unlock() comment header for details. | |
1237 | */ | |
a841796f PM |
1238 | local_irq_save(*flags); |
1239 | rcu_read_lock(); | |
f63ee72e | 1240 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1241 | if (unlikely(sighand == NULL)) { |
1242 | rcu_read_unlock(); | |
1243 | local_irq_restore(*flags); | |
f63ee72e | 1244 | break; |
a841796f | 1245 | } |
392809b2 ON |
1246 | /* |
1247 | * This sighand can be already freed and even reused, but | |
5f0d5a3a | 1248 | * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which |
392809b2 ON |
1249 | * initializes ->siglock: this slab can't go away, it has |
1250 | * the same object type, ->siglock can't be reinitialized. | |
1251 | * | |
1252 | * We need to ensure that tsk->sighand is still the same | |
1253 | * after we take the lock, we can race with de_thread() or | |
1254 | * __exit_signal(). In the latter case the next iteration | |
1255 | * must see ->sighand == NULL. | |
1256 | */ | |
a841796f PM |
1257 | spin_lock(&sighand->siglock); |
1258 | if (likely(sighand == tsk->sighand)) { | |
1259 | rcu_read_unlock(); | |
f63ee72e | 1260 | break; |
a841796f PM |
1261 | } |
1262 | spin_unlock(&sighand->siglock); | |
1263 | rcu_read_unlock(); | |
1264 | local_irq_restore(*flags); | |
f63ee72e ON |
1265 | } |
1266 | ||
1267 | return sighand; | |
1268 | } | |
1269 | ||
c69e8d9c DH |
1270 | /* |
1271 | * send signal info to all the members of a group | |
c69e8d9c | 1272 | */ |
1da177e4 LT |
1273 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1274 | { | |
694f690d DH |
1275 | int ret; |
1276 | ||
1277 | rcu_read_lock(); | |
1278 | ret = check_kill_permission(sig, info, p); | |
1279 | rcu_read_unlock(); | |
f63ee72e | 1280 | |
4a30debf ON |
1281 | if (!ret && sig) |
1282 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1283 | |
1284 | return ret; | |
1285 | } | |
1286 | ||
1287 | /* | |
146a505d | 1288 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1289 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1290 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1291 | */ |
c4b92fc1 | 1292 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1293 | { |
1294 | struct task_struct *p = NULL; | |
1295 | int retval, success; | |
1296 | ||
1da177e4 LT |
1297 | success = 0; |
1298 | retval = -ESRCH; | |
c4b92fc1 | 1299 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1300 | int err = group_send_sig_info(sig, info, p); |
1301 | success |= !err; | |
1302 | retval = err; | |
c4b92fc1 | 1303 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1304 | return success ? 0 : retval; |
1305 | } | |
1306 | ||
c4b92fc1 | 1307 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1308 | { |
d36174bc | 1309 | int error = -ESRCH; |
1da177e4 LT |
1310 | struct task_struct *p; |
1311 | ||
eca1a089 PM |
1312 | for (;;) { |
1313 | rcu_read_lock(); | |
1314 | p = pid_task(pid, PIDTYPE_PID); | |
1315 | if (p) | |
1316 | error = group_send_sig_info(sig, info, p); | |
1317 | rcu_read_unlock(); | |
1318 | if (likely(!p || error != -ESRCH)) | |
1319 | return error; | |
6ca25b55 | 1320 | |
eca1a089 PM |
1321 | /* |
1322 | * The task was unhashed in between, try again. If it | |
1323 | * is dead, pid_task() will return NULL, if we race with | |
1324 | * de_thread() it will find the new leader. | |
1325 | */ | |
1326 | } | |
1da177e4 LT |
1327 | } |
1328 | ||
6c478ae9 | 1329 | static int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1330 | { |
1331 | int error; | |
1332 | rcu_read_lock(); | |
b488893a | 1333 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1334 | rcu_read_unlock(); |
1335 | return error; | |
1336 | } | |
1337 | ||
d178bc3a SH |
1338 | static int kill_as_cred_perm(const struct cred *cred, |
1339 | struct task_struct *target) | |
1340 | { | |
1341 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1342 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1343 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1344 | return 0; |
1345 | return 1; | |
1346 | } | |
1347 | ||
2425c08b | 1348 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1349 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1350 | const struct cred *cred, u32 secid) | |
46113830 HW |
1351 | { |
1352 | int ret = -EINVAL; | |
1353 | struct task_struct *p; | |
14d8c9f3 | 1354 | unsigned long flags; |
46113830 HW |
1355 | |
1356 | if (!valid_signal(sig)) | |
1357 | return ret; | |
1358 | ||
14d8c9f3 | 1359 | rcu_read_lock(); |
2425c08b | 1360 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1361 | if (!p) { |
1362 | ret = -ESRCH; | |
1363 | goto out_unlock; | |
1364 | } | |
d178bc3a | 1365 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1366 | ret = -EPERM; |
1367 | goto out_unlock; | |
1368 | } | |
8f95dc58 DQ |
1369 | ret = security_task_kill(p, info, sig, secid); |
1370 | if (ret) | |
1371 | goto out_unlock; | |
14d8c9f3 TG |
1372 | |
1373 | if (sig) { | |
1374 | if (lock_task_sighand(p, &flags)) { | |
1375 | ret = __send_signal(sig, info, p, 1, 0); | |
1376 | unlock_task_sighand(p, &flags); | |
1377 | } else | |
1378 | ret = -ESRCH; | |
46113830 HW |
1379 | } |
1380 | out_unlock: | |
14d8c9f3 | 1381 | rcu_read_unlock(); |
46113830 HW |
1382 | return ret; |
1383 | } | |
d178bc3a | 1384 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1385 | |
1386 | /* | |
1387 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1388 | * | |
1389 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1390 | * is probably wrong. Should make it like BSD or SYSV. | |
1391 | */ | |
1392 | ||
bc64efd2 | 1393 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1394 | { |
8d42db18 | 1395 | int ret; |
d5df763b PE |
1396 | |
1397 | if (pid > 0) { | |
1398 | rcu_read_lock(); | |
1399 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1400 | rcu_read_unlock(); | |
1401 | return ret; | |
1402 | } | |
1403 | ||
1404 | read_lock(&tasklist_lock); | |
1405 | if (pid != -1) { | |
1406 | ret = __kill_pgrp_info(sig, info, | |
1407 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1408 | } else { | |
1da177e4 LT |
1409 | int retval = 0, count = 0; |
1410 | struct task_struct * p; | |
1411 | ||
1da177e4 | 1412 | for_each_process(p) { |
d25141a8 SB |
1413 | if (task_pid_vnr(p) > 1 && |
1414 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1415 | int err = group_send_sig_info(sig, info, p); |
1416 | ++count; | |
1417 | if (err != -EPERM) | |
1418 | retval = err; | |
1419 | } | |
1420 | } | |
8d42db18 | 1421 | ret = count ? retval : -ESRCH; |
1da177e4 | 1422 | } |
d5df763b PE |
1423 | read_unlock(&tasklist_lock); |
1424 | ||
8d42db18 | 1425 | return ret; |
1da177e4 LT |
1426 | } |
1427 | ||
1428 | /* | |
1429 | * These are for backward compatibility with the rest of the kernel source. | |
1430 | */ | |
1431 | ||
5aba085e | 1432 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1433 | { |
1da177e4 LT |
1434 | /* |
1435 | * Make sure legacy kernel users don't send in bad values | |
1436 | * (normal paths check this in check_kill_permission). | |
1437 | */ | |
7ed20e1a | 1438 | if (!valid_signal(sig)) |
1da177e4 LT |
1439 | return -EINVAL; |
1440 | ||
4a30debf | 1441 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1442 | } |
1443 | ||
b67a1b9e ON |
1444 | #define __si_special(priv) \ |
1445 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1446 | ||
1da177e4 LT |
1447 | int |
1448 | send_sig(int sig, struct task_struct *p, int priv) | |
1449 | { | |
b67a1b9e | 1450 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1451 | } |
1452 | ||
1da177e4 LT |
1453 | void |
1454 | force_sig(int sig, struct task_struct *p) | |
1455 | { | |
b67a1b9e | 1456 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1457 | } |
1458 | ||
1459 | /* | |
1460 | * When things go south during signal handling, we | |
1461 | * will force a SIGSEGV. And if the signal that caused | |
1462 | * the problem was already a SIGSEGV, we'll want to | |
1463 | * make sure we don't even try to deliver the signal.. | |
1464 | */ | |
1465 | int | |
1466 | force_sigsegv(int sig, struct task_struct *p) | |
1467 | { | |
1468 | if (sig == SIGSEGV) { | |
1469 | unsigned long flags; | |
1470 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1471 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1472 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1473 | } | |
1474 | force_sig(SIGSEGV, p); | |
1475 | return 0; | |
1476 | } | |
1477 | ||
c4b92fc1 EB |
1478 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1479 | { | |
146a505d PE |
1480 | int ret; |
1481 | ||
1482 | read_lock(&tasklist_lock); | |
1483 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1484 | read_unlock(&tasklist_lock); | |
1485 | ||
1486 | return ret; | |
c4b92fc1 EB |
1487 | } |
1488 | EXPORT_SYMBOL(kill_pgrp); | |
1489 | ||
1490 | int kill_pid(struct pid *pid, int sig, int priv) | |
1491 | { | |
1492 | return kill_pid_info(sig, __si_special(priv), pid); | |
1493 | } | |
1494 | EXPORT_SYMBOL(kill_pid); | |
1495 | ||
1da177e4 LT |
1496 | /* |
1497 | * These functions support sending signals using preallocated sigqueue | |
1498 | * structures. This is needed "because realtime applications cannot | |
1499 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1500 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1501 | * we allocate the sigqueue structure from the timer_create. If this |
1502 | * allocation fails we are able to report the failure to the application | |
1503 | * with an EAGAIN error. | |
1504 | */ | |
1da177e4 LT |
1505 | struct sigqueue *sigqueue_alloc(void) |
1506 | { | |
f84d49b2 | 1507 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1508 | |
f84d49b2 | 1509 | if (q) |
1da177e4 | 1510 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1511 | |
1512 | return q; | |
1da177e4 LT |
1513 | } |
1514 | ||
1515 | void sigqueue_free(struct sigqueue *q) | |
1516 | { | |
1517 | unsigned long flags; | |
60187d27 ON |
1518 | spinlock_t *lock = ¤t->sighand->siglock; |
1519 | ||
1da177e4 LT |
1520 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1521 | /* | |
c8e85b4f ON |
1522 | * We must hold ->siglock while testing q->list |
1523 | * to serialize with collect_signal() or with | |
da7978b0 | 1524 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1525 | */ |
60187d27 | 1526 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1527 | q->flags &= ~SIGQUEUE_PREALLOC; |
1528 | /* | |
1529 | * If it is queued it will be freed when dequeued, | |
1530 | * like the "regular" sigqueue. | |
1531 | */ | |
60187d27 | 1532 | if (!list_empty(&q->list)) |
c8e85b4f | 1533 | q = NULL; |
60187d27 ON |
1534 | spin_unlock_irqrestore(lock, flags); |
1535 | ||
c8e85b4f ON |
1536 | if (q) |
1537 | __sigqueue_free(q); | |
1da177e4 LT |
1538 | } |
1539 | ||
ac5c2153 | 1540 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1541 | { |
e62e6650 | 1542 | int sig = q->info.si_signo; |
2ca3515a | 1543 | struct sigpending *pending; |
e62e6650 | 1544 | unsigned long flags; |
163566f6 | 1545 | int ret, result; |
2ca3515a | 1546 | |
4cd4b6d4 | 1547 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1548 | |
1549 | ret = -1; | |
1550 | if (!likely(lock_task_sighand(t, &flags))) | |
1551 | goto ret; | |
1552 | ||
7e695a5e | 1553 | ret = 1; /* the signal is ignored */ |
163566f6 | 1554 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1555 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1556 | goto out; |
1557 | ||
1558 | ret = 0; | |
9e3bd6c3 PE |
1559 | if (unlikely(!list_empty(&q->list))) { |
1560 | /* | |
1561 | * If an SI_TIMER entry is already queue just increment | |
1562 | * the overrun count. | |
1563 | */ | |
9e3bd6c3 PE |
1564 | BUG_ON(q->info.si_code != SI_TIMER); |
1565 | q->info.si_overrun++; | |
163566f6 | 1566 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1567 | goto out; |
9e3bd6c3 | 1568 | } |
ba661292 | 1569 | q->info.si_overrun = 0; |
9e3bd6c3 | 1570 | |
9e3bd6c3 | 1571 | signalfd_notify(t, sig); |
2ca3515a | 1572 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1573 | list_add_tail(&q->list, &pending->list); |
1574 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1575 | complete_signal(sig, t, group); |
163566f6 | 1576 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1577 | out: |
163566f6 | 1578 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1579 | unlock_task_sighand(t, &flags); |
1580 | ret: | |
1581 | return ret; | |
9e3bd6c3 PE |
1582 | } |
1583 | ||
1da177e4 LT |
1584 | /* |
1585 | * Let a parent know about the death of a child. | |
1586 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1587 | * |
53c8f9f1 ON |
1588 | * Returns true if our parent ignored us and so we've switched to |
1589 | * self-reaping. | |
1da177e4 | 1590 | */ |
53c8f9f1 | 1591 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1592 | { |
1593 | struct siginfo info; | |
1594 | unsigned long flags; | |
1595 | struct sighand_struct *psig; | |
53c8f9f1 | 1596 | bool autoreap = false; |
bde8285e | 1597 | u64 utime, stime; |
1da177e4 LT |
1598 | |
1599 | BUG_ON(sig == -1); | |
1600 | ||
1601 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1602 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1603 | |
d21142ec | 1604 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1605 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1606 | ||
b6e238dc ON |
1607 | if (sig != SIGCHLD) { |
1608 | /* | |
1609 | * This is only possible if parent == real_parent. | |
1610 | * Check if it has changed security domain. | |
1611 | */ | |
1612 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1613 | sig = SIGCHLD; | |
1614 | } | |
1615 | ||
1da177e4 LT |
1616 | info.si_signo = sig; |
1617 | info.si_errno = 0; | |
b488893a | 1618 | /* |
32084504 EB |
1619 | * We are under tasklist_lock here so our parent is tied to |
1620 | * us and cannot change. | |
b488893a | 1621 | * |
32084504 EB |
1622 | * task_active_pid_ns will always return the same pid namespace |
1623 | * until a task passes through release_task. | |
b488893a PE |
1624 | * |
1625 | * write_lock() currently calls preempt_disable() which is the | |
1626 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1627 | * correct to rely on this | |
1628 | */ | |
1629 | rcu_read_lock(); | |
32084504 | 1630 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1631 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1632 | task_uid(tsk)); | |
b488893a PE |
1633 | rcu_read_unlock(); |
1634 | ||
bde8285e FW |
1635 | task_cputime(tsk, &utime, &stime); |
1636 | info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); | |
1637 | info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1638 | |
1639 | info.si_status = tsk->exit_code & 0x7f; | |
1640 | if (tsk->exit_code & 0x80) | |
1641 | info.si_code = CLD_DUMPED; | |
1642 | else if (tsk->exit_code & 0x7f) | |
1643 | info.si_code = CLD_KILLED; | |
1644 | else { | |
1645 | info.si_code = CLD_EXITED; | |
1646 | info.si_status = tsk->exit_code >> 8; | |
1647 | } | |
1648 | ||
1649 | psig = tsk->parent->sighand; | |
1650 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1651 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1652 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1653 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1654 | /* | |
1655 | * We are exiting and our parent doesn't care. POSIX.1 | |
1656 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1657 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1658 | * automatically and not left for our parent's wait4 call. | |
1659 | * Rather than having the parent do it as a magic kind of | |
1660 | * signal handler, we just set this to tell do_exit that we | |
1661 | * can be cleaned up without becoming a zombie. Note that | |
1662 | * we still call __wake_up_parent in this case, because a | |
1663 | * blocked sys_wait4 might now return -ECHILD. | |
1664 | * | |
1665 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1666 | * is implementation-defined: we do (if you don't want | |
1667 | * it, just use SIG_IGN instead). | |
1668 | */ | |
53c8f9f1 | 1669 | autoreap = true; |
1da177e4 | 1670 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1671 | sig = 0; |
1da177e4 | 1672 | } |
53c8f9f1 | 1673 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1674 | __group_send_sig_info(sig, &info, tsk->parent); |
1675 | __wake_up_parent(tsk, tsk->parent); | |
1676 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1677 | |
53c8f9f1 | 1678 | return autoreap; |
1da177e4 LT |
1679 | } |
1680 | ||
75b95953 TH |
1681 | /** |
1682 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1683 | * @tsk: task reporting the state change | |
1684 | * @for_ptracer: the notification is for ptracer | |
1685 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1686 | * | |
1687 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1688 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1689 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1690 | * | |
1691 | * CONTEXT: | |
1692 | * Must be called with tasklist_lock at least read locked. | |
1693 | */ | |
1694 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1695 | bool for_ptracer, int why) | |
1da177e4 LT |
1696 | { |
1697 | struct siginfo info; | |
1698 | unsigned long flags; | |
bc505a47 | 1699 | struct task_struct *parent; |
1da177e4 | 1700 | struct sighand_struct *sighand; |
bde8285e | 1701 | u64 utime, stime; |
1da177e4 | 1702 | |
75b95953 | 1703 | if (for_ptracer) { |
bc505a47 | 1704 | parent = tsk->parent; |
75b95953 | 1705 | } else { |
bc505a47 ON |
1706 | tsk = tsk->group_leader; |
1707 | parent = tsk->real_parent; | |
1708 | } | |
1709 | ||
1da177e4 LT |
1710 | info.si_signo = SIGCHLD; |
1711 | info.si_errno = 0; | |
b488893a | 1712 | /* |
5aba085e | 1713 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1714 | */ |
1715 | rcu_read_lock(); | |
17cf22c3 | 1716 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1717 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1718 | rcu_read_unlock(); |
1719 | ||
bde8285e FW |
1720 | task_cputime(tsk, &utime, &stime); |
1721 | info.si_utime = nsec_to_clock_t(utime); | |
1722 | info.si_stime = nsec_to_clock_t(stime); | |
1da177e4 LT |
1723 | |
1724 | info.si_code = why; | |
1725 | switch (why) { | |
1726 | case CLD_CONTINUED: | |
1727 | info.si_status = SIGCONT; | |
1728 | break; | |
1729 | case CLD_STOPPED: | |
1730 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1731 | break; | |
1732 | case CLD_TRAPPED: | |
1733 | info.si_status = tsk->exit_code & 0x7f; | |
1734 | break; | |
1735 | default: | |
1736 | BUG(); | |
1737 | } | |
1738 | ||
1739 | sighand = parent->sighand; | |
1740 | spin_lock_irqsave(&sighand->siglock, flags); | |
1741 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1742 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1743 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1744 | /* | |
1745 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1746 | */ | |
1747 | __wake_up_parent(tsk, parent); | |
1748 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1749 | } | |
1750 | ||
d5f70c00 ON |
1751 | static inline int may_ptrace_stop(void) |
1752 | { | |
d21142ec | 1753 | if (!likely(current->ptrace)) |
d5f70c00 | 1754 | return 0; |
d5f70c00 ON |
1755 | /* |
1756 | * Are we in the middle of do_coredump? | |
1757 | * If so and our tracer is also part of the coredump stopping | |
1758 | * is a deadlock situation, and pointless because our tracer | |
1759 | * is dead so don't allow us to stop. | |
1760 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1761 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1762 | * is safe to enter schedule(). |
9899d11f ON |
1763 | * |
1764 | * This is almost outdated, a task with the pending SIGKILL can't | |
1765 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1766 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1767 | */ |
999d9fc1 | 1768 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1769 | unlikely(current->mm == current->parent->mm)) |
1770 | return 0; | |
1771 | ||
1772 | return 1; | |
1773 | } | |
1774 | ||
1a669c2f | 1775 | /* |
5aba085e | 1776 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1777 | * Called with the siglock held. |
1778 | */ | |
1779 | static int sigkill_pending(struct task_struct *tsk) | |
1780 | { | |
3d749b9e ON |
1781 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1782 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1783 | } |
1784 | ||
1da177e4 LT |
1785 | /* |
1786 | * This must be called with current->sighand->siglock held. | |
1787 | * | |
1788 | * This should be the path for all ptrace stops. | |
1789 | * We always set current->last_siginfo while stopped here. | |
1790 | * That makes it a way to test a stopped process for | |
1791 | * being ptrace-stopped vs being job-control-stopped. | |
1792 | * | |
20686a30 ON |
1793 | * If we actually decide not to stop at all because the tracer |
1794 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1795 | */ |
fe1bc6a0 | 1796 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1797 | __releases(¤t->sighand->siglock) |
1798 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1799 | { |
ceb6bd67 TH |
1800 | bool gstop_done = false; |
1801 | ||
1a669c2f RM |
1802 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1803 | /* | |
1804 | * The arch code has something special to do before a | |
1805 | * ptrace stop. This is allowed to block, e.g. for faults | |
1806 | * on user stack pages. We can't keep the siglock while | |
1807 | * calling arch_ptrace_stop, so we must release it now. | |
1808 | * To preserve proper semantics, we must do this before | |
1809 | * any signal bookkeeping like checking group_stop_count. | |
1810 | * Meanwhile, a SIGKILL could come in before we retake the | |
1811 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1812 | * So after regaining the lock, we must check for SIGKILL. | |
1813 | */ | |
1814 | spin_unlock_irq(¤t->sighand->siglock); | |
1815 | arch_ptrace_stop(exit_code, info); | |
1816 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1817 | if (sigkill_pending(current)) |
1818 | return; | |
1a669c2f RM |
1819 | } |
1820 | ||
1da177e4 | 1821 | /* |
81be24b8 TH |
1822 | * We're committing to trapping. TRACED should be visible before |
1823 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1824 | * Also, transition to TRACED and updates to ->jobctl should be | |
1825 | * atomic with respect to siglock and should be done after the arch | |
1826 | * hook as siglock is released and regrabbed across it. | |
1da177e4 | 1827 | */ |
81be24b8 | 1828 | set_current_state(TASK_TRACED); |
1da177e4 LT |
1829 | |
1830 | current->last_siginfo = info; | |
1831 | current->exit_code = exit_code; | |
1832 | ||
d79fdd6d | 1833 | /* |
0ae8ce1c TH |
1834 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1835 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1836 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1837 | * could be clear now. We act as if SIGCONT is received after | |
1838 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1839 | */ |
a8f072c1 | 1840 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1841 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1842 | |
fb1d910c | 1843 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1844 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1845 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1846 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1847 | |
81be24b8 | 1848 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1849 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1850 | |
1da177e4 LT |
1851 | spin_unlock_irq(¤t->sighand->siglock); |
1852 | read_lock(&tasklist_lock); | |
3d749b9e | 1853 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1854 | /* |
1855 | * Notify parents of the stop. | |
1856 | * | |
1857 | * While ptraced, there are two parents - the ptracer and | |
1858 | * the real_parent of the group_leader. The ptracer should | |
1859 | * know about every stop while the real parent is only | |
1860 | * interested in the completion of group stop. The states | |
1861 | * for the two don't interact with each other. Notify | |
1862 | * separately unless they're gonna be duplicates. | |
1863 | */ | |
1864 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1865 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1866 | do_notify_parent_cldstop(current, false, why); |
1867 | ||
53da1d94 MS |
1868 | /* |
1869 | * Don't want to allow preemption here, because | |
1870 | * sys_ptrace() needs this task to be inactive. | |
1871 | * | |
1872 | * XXX: implement read_unlock_no_resched(). | |
1873 | */ | |
1874 | preempt_disable(); | |
1da177e4 | 1875 | read_unlock(&tasklist_lock); |
53da1d94 | 1876 | preempt_enable_no_resched(); |
5d8f72b5 | 1877 | freezable_schedule(); |
1da177e4 LT |
1878 | } else { |
1879 | /* | |
1880 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1881 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1882 | * |
1883 | * If @gstop_done, the ptracer went away between group stop | |
1884 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1885 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1886 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1887 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1888 | */ |
ceb6bd67 TH |
1889 | if (gstop_done) |
1890 | do_notify_parent_cldstop(current, false, why); | |
1891 | ||
9899d11f | 1892 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 1893 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1894 | if (clear_code) |
1895 | current->exit_code = 0; | |
6405f7f4 | 1896 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1897 | } |
1898 | ||
1899 | /* | |
1900 | * We are back. Now reacquire the siglock before touching | |
1901 | * last_siginfo, so that we are sure to have synchronized with | |
1902 | * any signal-sending on another CPU that wants to examine it. | |
1903 | */ | |
1904 | spin_lock_irq(¤t->sighand->siglock); | |
1905 | current->last_siginfo = NULL; | |
1906 | ||
544b2c91 TH |
1907 | /* LISTENING can be set only during STOP traps, clear it */ |
1908 | current->jobctl &= ~JOBCTL_LISTENING; | |
1909 | ||
1da177e4 LT |
1910 | /* |
1911 | * Queued signals ignored us while we were stopped for tracing. | |
1912 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1913 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1914 | */ |
b74d0deb | 1915 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1916 | } |
1917 | ||
3544d72a | 1918 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1919 | { |
1920 | siginfo_t info; | |
1921 | ||
1da177e4 | 1922 | memset(&info, 0, sizeof info); |
3544d72a | 1923 | info.si_signo = signr; |
1da177e4 | 1924 | info.si_code = exit_code; |
b488893a | 1925 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1926 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1927 | |
1928 | /* Let the debugger run. */ | |
3544d72a TH |
1929 | ptrace_stop(exit_code, why, 1, &info); |
1930 | } | |
1931 | ||
1932 | void ptrace_notify(int exit_code) | |
1933 | { | |
1934 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
1935 | if (unlikely(current->task_works)) |
1936 | task_work_run(); | |
3544d72a | 1937 | |
1da177e4 | 1938 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1939 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1940 | spin_unlock_irq(¤t->sighand->siglock); |
1941 | } | |
1942 | ||
73ddff2b TH |
1943 | /** |
1944 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1945 | * @signr: signr causing group stop if initiating | |
1946 | * | |
1947 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1948 | * and participate in it. If already set, participate in the existing | |
1949 | * group stop. If participated in a group stop (and thus slept), %true is | |
1950 | * returned with siglock released. | |
1951 | * | |
1952 | * If ptraced, this function doesn't handle stop itself. Instead, | |
1953 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
1954 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
1955 | * places afterwards. | |
1956 | * | |
1957 | * CONTEXT: | |
1958 | * Must be called with @current->sighand->siglock held, which is released | |
1959 | * on %true return. | |
1960 | * | |
1961 | * RETURNS: | |
1962 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
1963 | * %true if participated in group stop. | |
1da177e4 | 1964 | */ |
73ddff2b TH |
1965 | static bool do_signal_stop(int signr) |
1966 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
1967 | { |
1968 | struct signal_struct *sig = current->signal; | |
1da177e4 | 1969 | |
a8f072c1 | 1970 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
b76808e6 | 1971 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
f558b7e4 ON |
1972 | struct task_struct *t; |
1973 | ||
a8f072c1 TH |
1974 | /* signr will be recorded in task->jobctl for retries */ |
1975 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 1976 | |
a8f072c1 | 1977 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 1978 | unlikely(signal_group_exit(sig))) |
73ddff2b | 1979 | return false; |
1da177e4 | 1980 | /* |
408a37de TH |
1981 | * There is no group stop already in progress. We must |
1982 | * initiate one now. | |
1983 | * | |
1984 | * While ptraced, a task may be resumed while group stop is | |
1985 | * still in effect and then receive a stop signal and | |
1986 | * initiate another group stop. This deviates from the | |
1987 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
1988 | * cause two group stops when !ptraced. That is why we |
1989 | * also check !task_is_stopped(t) below. | |
408a37de TH |
1990 | * |
1991 | * The condition can be distinguished by testing whether | |
1992 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
1993 | * group_exit_code in such case. | |
1994 | * | |
1995 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
1996 | * an intervening stop signal is required to cause two | |
1997 | * continued events regardless of ptrace. | |
1da177e4 | 1998 | */ |
408a37de TH |
1999 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2000 | sig->group_exit_code = signr; | |
1da177e4 | 2001 | |
7dd3db54 TH |
2002 | sig->group_stop_count = 0; |
2003 | ||
2004 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2005 | sig->group_stop_count++; | |
1da177e4 | 2006 | |
8d38f203 ON |
2007 | t = current; |
2008 | while_each_thread(current, t) { | |
1da177e4 | 2009 | /* |
a122b341 ON |
2010 | * Setting state to TASK_STOPPED for a group |
2011 | * stop is always done with the siglock held, | |
2012 | * so this check has no races. | |
1da177e4 | 2013 | */ |
7dd3db54 TH |
2014 | if (!task_is_stopped(t) && |
2015 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2016 | sig->group_stop_count++; |
fb1d910c TH |
2017 | if (likely(!(t->ptrace & PT_SEIZED))) |
2018 | signal_wake_up(t, 0); | |
2019 | else | |
2020 | ptrace_trap_notify(t); | |
a122b341 | 2021 | } |
d79fdd6d | 2022 | } |
1da177e4 | 2023 | } |
73ddff2b | 2024 | |
d21142ec | 2025 | if (likely(!current->ptrace)) { |
5224fa36 | 2026 | int notify = 0; |
1da177e4 | 2027 | |
5224fa36 TH |
2028 | /* |
2029 | * If there are no other threads in the group, or if there | |
2030 | * is a group stop in progress and we are the last to stop, | |
2031 | * report to the parent. | |
2032 | */ | |
2033 | if (task_participate_group_stop(current)) | |
2034 | notify = CLD_STOPPED; | |
2035 | ||
ae6d2ed7 | 2036 | __set_current_state(TASK_STOPPED); |
5224fa36 TH |
2037 | spin_unlock_irq(¤t->sighand->siglock); |
2038 | ||
62bcf9d9 TH |
2039 | /* |
2040 | * Notify the parent of the group stop completion. Because | |
2041 | * we're not holding either the siglock or tasklist_lock | |
2042 | * here, ptracer may attach inbetween; however, this is for | |
2043 | * group stop and should always be delivered to the real | |
2044 | * parent of the group leader. The new ptracer will get | |
2045 | * its notification when this task transitions into | |
2046 | * TASK_TRACED. | |
2047 | */ | |
5224fa36 TH |
2048 | if (notify) { |
2049 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2050 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2051 | read_unlock(&tasklist_lock); |
2052 | } | |
2053 | ||
2054 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
5d8f72b5 | 2055 | freezable_schedule(); |
73ddff2b | 2056 | return true; |
d79fdd6d | 2057 | } else { |
73ddff2b TH |
2058 | /* |
2059 | * While ptraced, group stop is handled by STOP trap. | |
2060 | * Schedule it and let the caller deal with it. | |
2061 | */ | |
2062 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2063 | return false; | |
ae6d2ed7 | 2064 | } |
73ddff2b | 2065 | } |
1da177e4 | 2066 | |
73ddff2b TH |
2067 | /** |
2068 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2069 | * | |
3544d72a TH |
2070 | * When PT_SEIZED, it's used for both group stop and explicit |
2071 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2072 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2073 | * the stop signal; otherwise, %SIGTRAP. | |
2074 | * | |
2075 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2076 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2077 | * |
2078 | * CONTEXT: | |
2079 | * Must be called with @current->sighand->siglock held, which may be | |
2080 | * released and re-acquired before returning with intervening sleep. | |
2081 | */ | |
2082 | static void do_jobctl_trap(void) | |
2083 | { | |
3544d72a | 2084 | struct signal_struct *signal = current->signal; |
73ddff2b | 2085 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2086 | |
3544d72a TH |
2087 | if (current->ptrace & PT_SEIZED) { |
2088 | if (!signal->group_stop_count && | |
2089 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2090 | signr = SIGTRAP; | |
2091 | WARN_ON_ONCE(!signr); | |
2092 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2093 | CLD_STOPPED); | |
2094 | } else { | |
2095 | WARN_ON_ONCE(!signr); | |
2096 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2097 | current->exit_code = 0; | |
ae6d2ed7 | 2098 | } |
1da177e4 LT |
2099 | } |
2100 | ||
94eb22d5 | 2101 | static int ptrace_signal(int signr, siginfo_t *info) |
18c98b65 | 2102 | { |
b7f9591c | 2103 | ptrace_signal_deliver(); |
8a352418 ON |
2104 | /* |
2105 | * We do not check sig_kernel_stop(signr) but set this marker | |
2106 | * unconditionally because we do not know whether debugger will | |
2107 | * change signr. This flag has no meaning unless we are going | |
2108 | * to stop after return from ptrace_stop(). In this case it will | |
2109 | * be checked in do_signal_stop(), we should only stop if it was | |
2110 | * not cleared by SIGCONT while we were sleeping. See also the | |
2111 | * comment in dequeue_signal(). | |
2112 | */ | |
2113 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2114 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2115 | |
2116 | /* We're back. Did the debugger cancel the sig? */ | |
2117 | signr = current->exit_code; | |
2118 | if (signr == 0) | |
2119 | return signr; | |
2120 | ||
2121 | current->exit_code = 0; | |
2122 | ||
5aba085e RD |
2123 | /* |
2124 | * Update the siginfo structure if the signal has | |
2125 | * changed. If the debugger wanted something | |
2126 | * specific in the siginfo structure then it should | |
2127 | * have updated *info via PTRACE_SETSIGINFO. | |
2128 | */ | |
18c98b65 RM |
2129 | if (signr != info->si_signo) { |
2130 | info->si_signo = signr; | |
2131 | info->si_errno = 0; | |
2132 | info->si_code = SI_USER; | |
6b550f94 | 2133 | rcu_read_lock(); |
18c98b65 | 2134 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2135 | info->si_uid = from_kuid_munged(current_user_ns(), |
2136 | task_uid(current->parent)); | |
6b550f94 | 2137 | rcu_read_unlock(); |
18c98b65 RM |
2138 | } |
2139 | ||
2140 | /* If the (new) signal is now blocked, requeue it. */ | |
2141 | if (sigismember(¤t->blocked, signr)) { | |
2142 | specific_send_sig_info(signr, info, current); | |
2143 | signr = 0; | |
2144 | } | |
2145 | ||
2146 | return signr; | |
2147 | } | |
2148 | ||
828b1f65 | 2149 | int get_signal(struct ksignal *ksig) |
1da177e4 | 2150 | { |
f6b76d4f ON |
2151 | struct sighand_struct *sighand = current->sighand; |
2152 | struct signal_struct *signal = current->signal; | |
2153 | int signr; | |
1da177e4 | 2154 | |
f784e8a7 ON |
2155 | if (unlikely(current->task_works)) |
2156 | task_work_run(); | |
72667028 | 2157 | |
0326f5a9 SD |
2158 | if (unlikely(uprobe_deny_signal())) |
2159 | return 0; | |
2160 | ||
13b1c3d4 | 2161 | /* |
5d8f72b5 ON |
2162 | * Do this once, we can't return to user-mode if freezing() == T. |
2163 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2164 | * thus do not need another check after return. | |
13b1c3d4 | 2165 | */ |
fc558a74 RW |
2166 | try_to_freeze(); |
2167 | ||
5d8f72b5 | 2168 | relock: |
f6b76d4f | 2169 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2170 | /* |
2171 | * Every stopped thread goes here after wakeup. Check to see if | |
2172 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2173 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2174 | */ | |
f6b76d4f | 2175 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2176 | int why; |
2177 | ||
2178 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2179 | why = CLD_CONTINUED; | |
2180 | else | |
2181 | why = CLD_STOPPED; | |
2182 | ||
f6b76d4f | 2183 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2184 | |
ae6d2ed7 | 2185 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2186 | |
ceb6bd67 TH |
2187 | /* |
2188 | * Notify the parent that we're continuing. This event is | |
2189 | * always per-process and doesn't make whole lot of sense | |
2190 | * for ptracers, who shouldn't consume the state via | |
2191 | * wait(2) either, but, for backward compatibility, notify | |
2192 | * the ptracer of the group leader too unless it's gonna be | |
2193 | * a duplicate. | |
2194 | */ | |
edf2ed15 | 2195 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2196 | do_notify_parent_cldstop(current, false, why); |
2197 | ||
bb3696da ON |
2198 | if (ptrace_reparented(current->group_leader)) |
2199 | do_notify_parent_cldstop(current->group_leader, | |
2200 | true, why); | |
edf2ed15 | 2201 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2202 | |
e4420551 ON |
2203 | goto relock; |
2204 | } | |
2205 | ||
1da177e4 LT |
2206 | for (;;) { |
2207 | struct k_sigaction *ka; | |
1be53963 | 2208 | |
dd1d6772 TH |
2209 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2210 | do_signal_stop(0)) | |
7bcf6a2c | 2211 | goto relock; |
1be53963 | 2212 | |
73ddff2b TH |
2213 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2214 | do_jobctl_trap(); | |
2215 | spin_unlock_irq(&sighand->siglock); | |
2216 | goto relock; | |
2217 | } | |
1da177e4 | 2218 | |
828b1f65 | 2219 | signr = dequeue_signal(current, ¤t->blocked, &ksig->info); |
7bcf6a2c | 2220 | |
dd1d6772 TH |
2221 | if (!signr) |
2222 | break; /* will return 0 */ | |
7bcf6a2c | 2223 | |
8a352418 | 2224 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
828b1f65 | 2225 | signr = ptrace_signal(signr, &ksig->info); |
dd1d6772 TH |
2226 | if (!signr) |
2227 | continue; | |
1da177e4 LT |
2228 | } |
2229 | ||
dd1d6772 TH |
2230 | ka = &sighand->action[signr-1]; |
2231 | ||
f9d4257e | 2232 | /* Trace actually delivered signals. */ |
828b1f65 | 2233 | trace_signal_deliver(signr, &ksig->info, ka); |
f9d4257e | 2234 | |
1da177e4 LT |
2235 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2236 | continue; | |
2237 | if (ka->sa.sa_handler != SIG_DFL) { | |
2238 | /* Run the handler. */ | |
828b1f65 | 2239 | ksig->ka = *ka; |
1da177e4 LT |
2240 | |
2241 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2242 | ka->sa.sa_handler = SIG_DFL; | |
2243 | ||
2244 | break; /* will return non-zero "signr" value */ | |
2245 | } | |
2246 | ||
2247 | /* | |
2248 | * Now we are doing the default action for this signal. | |
2249 | */ | |
2250 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2251 | continue; | |
2252 | ||
84d73786 | 2253 | /* |
0fbc26a6 | 2254 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2255 | * Container-init gets no signals it doesn't want from same |
2256 | * container. | |
2257 | * | |
2258 | * Note that if global/container-init sees a sig_kernel_only() | |
2259 | * signal here, the signal must have been generated internally | |
2260 | * or must have come from an ancestor namespace. In either | |
2261 | * case, the signal cannot be dropped. | |
84d73786 | 2262 | */ |
fae5fa44 | 2263 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2264 | !sig_kernel_only(signr)) |
1da177e4 LT |
2265 | continue; |
2266 | ||
2267 | if (sig_kernel_stop(signr)) { | |
2268 | /* | |
2269 | * The default action is to stop all threads in | |
2270 | * the thread group. The job control signals | |
2271 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2272 | * always works. Note that siglock needs to be | |
2273 | * dropped during the call to is_orphaned_pgrp() | |
2274 | * because of lock ordering with tasklist_lock. | |
2275 | * This allows an intervening SIGCONT to be posted. | |
2276 | * We need to check for that and bail out if necessary. | |
2277 | */ | |
2278 | if (signr != SIGSTOP) { | |
f6b76d4f | 2279 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2280 | |
2281 | /* signals can be posted during this window */ | |
2282 | ||
3e7cd6c4 | 2283 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2284 | goto relock; |
2285 | ||
f6b76d4f | 2286 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2287 | } |
2288 | ||
828b1f65 | 2289 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
1da177e4 LT |
2290 | /* It released the siglock. */ |
2291 | goto relock; | |
2292 | } | |
2293 | ||
2294 | /* | |
2295 | * We didn't actually stop, due to a race | |
2296 | * with SIGCONT or something like that. | |
2297 | */ | |
2298 | continue; | |
2299 | } | |
2300 | ||
f6b76d4f | 2301 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2302 | |
2303 | /* | |
2304 | * Anything else is fatal, maybe with a core dump. | |
2305 | */ | |
2306 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2307 | |
1da177e4 | 2308 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2309 | if (print_fatal_signals) |
828b1f65 | 2310 | print_fatal_signal(ksig->info.si_signo); |
2b5faa4c | 2311 | proc_coredump_connector(current); |
1da177e4 LT |
2312 | /* |
2313 | * If it was able to dump core, this kills all | |
2314 | * other threads in the group and synchronizes with | |
2315 | * their demise. If we lost the race with another | |
2316 | * thread getting here, it set group_exit_code | |
2317 | * first and our do_group_exit call below will use | |
2318 | * that value and ignore the one we pass it. | |
2319 | */ | |
828b1f65 | 2320 | do_coredump(&ksig->info); |
1da177e4 LT |
2321 | } |
2322 | ||
2323 | /* | |
2324 | * Death signals, no core dump. | |
2325 | */ | |
828b1f65 | 2326 | do_group_exit(ksig->info.si_signo); |
1da177e4 LT |
2327 | /* NOTREACHED */ |
2328 | } | |
f6b76d4f | 2329 | spin_unlock_irq(&sighand->siglock); |
828b1f65 RW |
2330 | |
2331 | ksig->sig = signr; | |
2332 | return ksig->sig > 0; | |
1da177e4 LT |
2333 | } |
2334 | ||
5e6292c0 | 2335 | /** |
efee984c | 2336 | * signal_delivered - |
10b1c7ac | 2337 | * @ksig: kernel signal struct |
efee984c | 2338 | * @stepping: nonzero if debugger single-step or block-step in use |
5e6292c0 | 2339 | * |
e227867f | 2340 | * This function should be called when a signal has successfully been |
10b1c7ac | 2341 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
efee984c | 2342 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER |
10b1c7ac | 2343 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
5e6292c0 | 2344 | */ |
10b1c7ac | 2345 | static void signal_delivered(struct ksignal *ksig, int stepping) |
5e6292c0 MF |
2346 | { |
2347 | sigset_t blocked; | |
2348 | ||
a610d6e6 AV |
2349 | /* A signal was successfully delivered, and the |
2350 | saved sigmask was stored on the signal frame, | |
2351 | and will be restored by sigreturn. So we can | |
2352 | simply clear the restore sigmask flag. */ | |
2353 | clear_restore_sigmask(); | |
2354 | ||
10b1c7ac RW |
2355 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
2356 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) | |
2357 | sigaddset(&blocked, ksig->sig); | |
5e6292c0 | 2358 | set_current_blocked(&blocked); |
df5601f9 | 2359 | tracehook_signal_handler(stepping); |
5e6292c0 MF |
2360 | } |
2361 | ||
2ce5da17 AV |
2362 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2363 | { | |
2364 | if (failed) | |
2365 | force_sigsegv(ksig->sig, current); | |
2366 | else | |
10b1c7ac | 2367 | signal_delivered(ksig, stepping); |
2ce5da17 AV |
2368 | } |
2369 | ||
0edceb7b ON |
2370 | /* |
2371 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2372 | * group-wide signal. Other threads should be notified now to take |
2373 | * the shared signals in @which since we will not. | |
0edceb7b | 2374 | */ |
f646e227 | 2375 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2376 | { |
f646e227 | 2377 | sigset_t retarget; |
0edceb7b ON |
2378 | struct task_struct *t; |
2379 | ||
f646e227 ON |
2380 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2381 | if (sigisemptyset(&retarget)) | |
2382 | return; | |
2383 | ||
0edceb7b ON |
2384 | t = tsk; |
2385 | while_each_thread(tsk, t) { | |
fec9993d ON |
2386 | if (t->flags & PF_EXITING) |
2387 | continue; | |
2388 | ||
2389 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2390 | continue; | |
2391 | /* Remove the signals this thread can handle. */ | |
2392 | sigandsets(&retarget, &retarget, &t->blocked); | |
2393 | ||
2394 | if (!signal_pending(t)) | |
2395 | signal_wake_up(t, 0); | |
2396 | ||
2397 | if (sigisemptyset(&retarget)) | |
2398 | break; | |
0edceb7b ON |
2399 | } |
2400 | } | |
2401 | ||
d12619b5 ON |
2402 | void exit_signals(struct task_struct *tsk) |
2403 | { | |
2404 | int group_stop = 0; | |
f646e227 | 2405 | sigset_t unblocked; |
d12619b5 | 2406 | |
77e4ef99 TH |
2407 | /* |
2408 | * @tsk is about to have PF_EXITING set - lock out users which | |
2409 | * expect stable threadgroup. | |
2410 | */ | |
780de9dd | 2411 | cgroup_threadgroup_change_begin(tsk); |
77e4ef99 | 2412 | |
5dee1707 ON |
2413 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2414 | tsk->flags |= PF_EXITING; | |
780de9dd | 2415 | cgroup_threadgroup_change_end(tsk); |
5dee1707 | 2416 | return; |
d12619b5 ON |
2417 | } |
2418 | ||
5dee1707 | 2419 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2420 | /* |
2421 | * From now this task is not visible for group-wide signals, | |
2422 | * see wants_signal(), do_signal_stop(). | |
2423 | */ | |
2424 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2425 | |
780de9dd | 2426 | cgroup_threadgroup_change_end(tsk); |
77e4ef99 | 2427 | |
5dee1707 ON |
2428 | if (!signal_pending(tsk)) |
2429 | goto out; | |
2430 | ||
f646e227 ON |
2431 | unblocked = tsk->blocked; |
2432 | signotset(&unblocked); | |
2433 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2434 | |
a8f072c1 | 2435 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2436 | task_participate_group_stop(tsk)) |
edf2ed15 | 2437 | group_stop = CLD_STOPPED; |
5dee1707 | 2438 | out: |
d12619b5 ON |
2439 | spin_unlock_irq(&tsk->sighand->siglock); |
2440 | ||
62bcf9d9 TH |
2441 | /* |
2442 | * If group stop has completed, deliver the notification. This | |
2443 | * should always go to the real parent of the group leader. | |
2444 | */ | |
ae6d2ed7 | 2445 | if (unlikely(group_stop)) { |
d12619b5 | 2446 | read_lock(&tasklist_lock); |
62bcf9d9 | 2447 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2448 | read_unlock(&tasklist_lock); |
2449 | } | |
2450 | } | |
2451 | ||
1da177e4 LT |
2452 | EXPORT_SYMBOL(recalc_sigpending); |
2453 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2454 | EXPORT_SYMBOL(flush_signals); | |
2455 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2456 | EXPORT_SYMBOL(send_sig); |
2457 | EXPORT_SYMBOL(send_sig_info); | |
2458 | EXPORT_SYMBOL(sigprocmask); | |
1da177e4 LT |
2459 | |
2460 | /* | |
2461 | * System call entry points. | |
2462 | */ | |
2463 | ||
41c57892 RD |
2464 | /** |
2465 | * sys_restart_syscall - restart a system call | |
2466 | */ | |
754fe8d2 | 2467 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 | 2468 | { |
f56141e3 | 2469 | struct restart_block *restart = ¤t->restart_block; |
1da177e4 LT |
2470 | return restart->fn(restart); |
2471 | } | |
2472 | ||
2473 | long do_no_restart_syscall(struct restart_block *param) | |
2474 | { | |
2475 | return -EINTR; | |
2476 | } | |
2477 | ||
b182801a ON |
2478 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2479 | { | |
2480 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2481 | sigset_t newblocked; | |
2482 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2483 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2484 | retarget_shared_pending(tsk, &newblocked); |
2485 | } | |
2486 | tsk->blocked = *newset; | |
2487 | recalc_sigpending(); | |
2488 | } | |
2489 | ||
e6fa16ab ON |
2490 | /** |
2491 | * set_current_blocked - change current->blocked mask | |
2492 | * @newset: new mask | |
2493 | * | |
2494 | * It is wrong to change ->blocked directly, this helper should be used | |
2495 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2496 | */ |
77097ae5 AV |
2497 | void set_current_blocked(sigset_t *newset) |
2498 | { | |
77097ae5 | 2499 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2500 | __set_current_blocked(newset); |
77097ae5 AV |
2501 | } |
2502 | ||
2503 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2504 | { |
2505 | struct task_struct *tsk = current; | |
2506 | ||
c7be96af WL |
2507 | /* |
2508 | * In case the signal mask hasn't changed, there is nothing we need | |
2509 | * to do. The current->blocked shouldn't be modified by other task. | |
2510 | */ | |
2511 | if (sigequalsets(&tsk->blocked, newset)) | |
2512 | return; | |
2513 | ||
e6fa16ab | 2514 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2515 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2516 | spin_unlock_irq(&tsk->sighand->siglock); |
2517 | } | |
1da177e4 LT |
2518 | |
2519 | /* | |
2520 | * This is also useful for kernel threads that want to temporarily | |
2521 | * (or permanently) block certain signals. | |
2522 | * | |
2523 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2524 | * interface happily blocks "unblockable" signals like SIGKILL | |
2525 | * and friends. | |
2526 | */ | |
2527 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2528 | { | |
73ef4aeb ON |
2529 | struct task_struct *tsk = current; |
2530 | sigset_t newset; | |
1da177e4 | 2531 | |
73ef4aeb | 2532 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2533 | if (oldset) |
73ef4aeb | 2534 | *oldset = tsk->blocked; |
a26fd335 | 2535 | |
1da177e4 LT |
2536 | switch (how) { |
2537 | case SIG_BLOCK: | |
73ef4aeb | 2538 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2539 | break; |
2540 | case SIG_UNBLOCK: | |
702a5073 | 2541 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2542 | break; |
2543 | case SIG_SETMASK: | |
73ef4aeb | 2544 | newset = *set; |
1da177e4 LT |
2545 | break; |
2546 | default: | |
73ef4aeb | 2547 | return -EINVAL; |
1da177e4 | 2548 | } |
a26fd335 | 2549 | |
77097ae5 | 2550 | __set_current_blocked(&newset); |
73ef4aeb | 2551 | return 0; |
1da177e4 LT |
2552 | } |
2553 | ||
41c57892 RD |
2554 | /** |
2555 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2556 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2557 | * @nset: stores pending signals |
41c57892 RD |
2558 | * @oset: previous value of signal mask if non-null |
2559 | * @sigsetsize: size of sigset_t type | |
2560 | */ | |
bb7efee2 | 2561 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2562 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2563 | { |
1da177e4 | 2564 | sigset_t old_set, new_set; |
bb7efee2 | 2565 | int error; |
1da177e4 LT |
2566 | |
2567 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2568 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2569 | return -EINVAL; |
1da177e4 | 2570 | |
bb7efee2 ON |
2571 | old_set = current->blocked; |
2572 | ||
2573 | if (nset) { | |
2574 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2575 | return -EFAULT; | |
1da177e4 LT |
2576 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2577 | ||
bb7efee2 | 2578 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2579 | if (error) |
bb7efee2 ON |
2580 | return error; |
2581 | } | |
1da177e4 | 2582 | |
bb7efee2 ON |
2583 | if (oset) { |
2584 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2585 | return -EFAULT; | |
1da177e4 | 2586 | } |
bb7efee2 ON |
2587 | |
2588 | return 0; | |
1da177e4 LT |
2589 | } |
2590 | ||
322a56cb | 2591 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2592 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2593 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2594 | { |
322a56cb AV |
2595 | #ifdef __BIG_ENDIAN |
2596 | sigset_t old_set = current->blocked; | |
2597 | ||
2598 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2599 | if (sigsetsize != sizeof(sigset_t)) | |
2600 | return -EINVAL; | |
2601 | ||
2602 | if (nset) { | |
2603 | compat_sigset_t new32; | |
2604 | sigset_t new_set; | |
2605 | int error; | |
2606 | if (copy_from_user(&new32, nset, sizeof(compat_sigset_t))) | |
2607 | return -EFAULT; | |
2608 | ||
2609 | sigset_from_compat(&new_set, &new32); | |
2610 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2611 | ||
2612 | error = sigprocmask(how, &new_set, NULL); | |
2613 | if (error) | |
2614 | return error; | |
2615 | } | |
2616 | if (oset) { | |
2617 | compat_sigset_t old32; | |
2618 | sigset_to_compat(&old32, &old_set); | |
db61ec29 | 2619 | if (copy_to_user(oset, &old32, sizeof(compat_sigset_t))) |
322a56cb AV |
2620 | return -EFAULT; |
2621 | } | |
2622 | return 0; | |
2623 | #else | |
2624 | return sys_rt_sigprocmask(how, (sigset_t __user *)nset, | |
2625 | (sigset_t __user *)oset, sigsetsize); | |
2626 | #endif | |
2627 | } | |
2628 | #endif | |
1da177e4 | 2629 | |
fe9c1db2 | 2630 | static int do_sigpending(void *set, unsigned long sigsetsize) |
1da177e4 | 2631 | { |
1da177e4 | 2632 | if (sigsetsize > sizeof(sigset_t)) |
fe9c1db2 | 2633 | return -EINVAL; |
1da177e4 LT |
2634 | |
2635 | spin_lock_irq(¤t->sighand->siglock); | |
fe9c1db2 | 2636 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
2637 | ¤t->signal->shared_pending.signal); |
2638 | spin_unlock_irq(¤t->sighand->siglock); | |
2639 | ||
2640 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 AV |
2641 | sigandsets(set, ¤t->blocked, set); |
2642 | return 0; | |
5aba085e | 2643 | } |
1da177e4 | 2644 | |
41c57892 RD |
2645 | /** |
2646 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2647 | * while blocked | |
20f22ab4 | 2648 | * @uset: stores pending signals |
41c57892 RD |
2649 | * @sigsetsize: size of sigset_t type or larger |
2650 | */ | |
fe9c1db2 | 2651 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 2652 | { |
fe9c1db2 AV |
2653 | sigset_t set; |
2654 | int err = do_sigpending(&set, sigsetsize); | |
2655 | if (!err && copy_to_user(uset, &set, sigsetsize)) | |
2656 | err = -EFAULT; | |
2657 | return err; | |
2658 | } | |
2659 | ||
2660 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
2661 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
2662 | compat_size_t, sigsetsize) | |
1da177e4 | 2663 | { |
fe9c1db2 AV |
2664 | #ifdef __BIG_ENDIAN |
2665 | sigset_t set; | |
2666 | int err = do_sigpending(&set, sigsetsize); | |
2667 | if (!err) { | |
2668 | compat_sigset_t set32; | |
2669 | sigset_to_compat(&set32, &set); | |
2670 | /* we can get here only if sigsetsize <= sizeof(set) */ | |
2671 | if (copy_to_user(uset, &set32, sigsetsize)) | |
2672 | err = -EFAULT; | |
2673 | } | |
2674 | return err; | |
2675 | #else | |
2676 | return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize); | |
2677 | #endif | |
1da177e4 | 2678 | } |
fe9c1db2 | 2679 | #endif |
1da177e4 LT |
2680 | |
2681 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2682 | ||
ce395960 | 2683 | int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) |
1da177e4 LT |
2684 | { |
2685 | int err; | |
2686 | ||
2687 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2688 | return -EFAULT; | |
2689 | if (from->si_code < 0) | |
2690 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2691 | ? -EFAULT : 0; | |
2692 | /* | |
2693 | * If you change siginfo_t structure, please be sure | |
2694 | * this code is fixed accordingly. | |
fba2afaa DL |
2695 | * Please remember to update the signalfd_copyinfo() function |
2696 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2697 | * It should never copy any pad contained in the structure |
2698 | * to avoid security leaks, but must copy the generic | |
2699 | * 3 ints plus the relevant union member. | |
2700 | */ | |
2701 | err = __put_user(from->si_signo, &to->si_signo); | |
2702 | err |= __put_user(from->si_errno, &to->si_errno); | |
2703 | err |= __put_user((short)from->si_code, &to->si_code); | |
2704 | switch (from->si_code & __SI_MASK) { | |
2705 | case __SI_KILL: | |
2706 | err |= __put_user(from->si_pid, &to->si_pid); | |
2707 | err |= __put_user(from->si_uid, &to->si_uid); | |
2708 | break; | |
2709 | case __SI_TIMER: | |
2710 | err |= __put_user(from->si_tid, &to->si_tid); | |
2711 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2712 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2713 | break; | |
2714 | case __SI_POLL: | |
2715 | err |= __put_user(from->si_band, &to->si_band); | |
2716 | err |= __put_user(from->si_fd, &to->si_fd); | |
2717 | break; | |
2718 | case __SI_FAULT: | |
2719 | err |= __put_user(from->si_addr, &to->si_addr); | |
2720 | #ifdef __ARCH_SI_TRAPNO | |
2721 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2722 | #endif |
2723 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2724 | /* |
a337fdac | 2725 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2726 | * so check explicitly for the right codes here. |
a337fdac | 2727 | */ |
26135022 AA |
2728 | if (from->si_signo == SIGBUS && |
2729 | (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) | |
a337fdac | 2730 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); |
ee1b58d3 QR |
2731 | #endif |
2732 | #ifdef SEGV_BNDERR | |
26135022 AA |
2733 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) { |
2734 | err |= __put_user(from->si_lower, &to->si_lower); | |
2735 | err |= __put_user(from->si_upper, &to->si_upper); | |
2736 | } | |
cd0ea35f DH |
2737 | #endif |
2738 | #ifdef SEGV_PKUERR | |
2739 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR) | |
2740 | err |= __put_user(from->si_pkey, &to->si_pkey); | |
1da177e4 LT |
2741 | #endif |
2742 | break; | |
2743 | case __SI_CHLD: | |
2744 | err |= __put_user(from->si_pid, &to->si_pid); | |
2745 | err |= __put_user(from->si_uid, &to->si_uid); | |
2746 | err |= __put_user(from->si_status, &to->si_status); | |
2747 | err |= __put_user(from->si_utime, &to->si_utime); | |
2748 | err |= __put_user(from->si_stime, &to->si_stime); | |
2749 | break; | |
2750 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2751 | case __SI_MESGQ: /* But this is */ | |
2752 | err |= __put_user(from->si_pid, &to->si_pid); | |
2753 | err |= __put_user(from->si_uid, &to->si_uid); | |
2754 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2755 | break; | |
a0727e8c WD |
2756 | #ifdef __ARCH_SIGSYS |
2757 | case __SI_SYS: | |
2758 | err |= __put_user(from->si_call_addr, &to->si_call_addr); | |
2759 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2760 | err |= __put_user(from->si_arch, &to->si_arch); | |
2761 | break; | |
2762 | #endif | |
1da177e4 LT |
2763 | default: /* this is just in case for now ... */ |
2764 | err |= __put_user(from->si_pid, &to->si_pid); | |
2765 | err |= __put_user(from->si_uid, &to->si_uid); | |
2766 | break; | |
2767 | } | |
2768 | return err; | |
2769 | } | |
2770 | ||
2771 | #endif | |
2772 | ||
943df148 ON |
2773 | /** |
2774 | * do_sigtimedwait - wait for queued signals specified in @which | |
2775 | * @which: queued signals to wait for | |
2776 | * @info: if non-null, the signal's siginfo is returned here | |
2777 | * @ts: upper bound on process time suspension | |
2778 | */ | |
2779 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info, | |
2b1ecc3d | 2780 | const struct timespec *ts) |
943df148 | 2781 | { |
2456e855 | 2782 | ktime_t *to = NULL, timeout = KTIME_MAX; |
943df148 | 2783 | struct task_struct *tsk = current; |
943df148 | 2784 | sigset_t mask = *which; |
2b1ecc3d | 2785 | int sig, ret = 0; |
943df148 ON |
2786 | |
2787 | if (ts) { | |
2788 | if (!timespec_valid(ts)) | |
2789 | return -EINVAL; | |
2b1ecc3d TG |
2790 | timeout = timespec_to_ktime(*ts); |
2791 | to = &timeout; | |
943df148 ON |
2792 | } |
2793 | ||
2794 | /* | |
2795 | * Invert the set of allowed signals to get those we want to block. | |
2796 | */ | |
2797 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2798 | signotset(&mask); | |
2799 | ||
2800 | spin_lock_irq(&tsk->sighand->siglock); | |
2801 | sig = dequeue_signal(tsk, &mask, info); | |
2456e855 | 2802 | if (!sig && timeout) { |
943df148 ON |
2803 | /* |
2804 | * None ready, temporarily unblock those we're interested | |
2805 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2806 | * they arrive. Unblocking is always fine, we can avoid |
2807 | * set_current_blocked(). | |
943df148 ON |
2808 | */ |
2809 | tsk->real_blocked = tsk->blocked; | |
2810 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2811 | recalc_sigpending(); | |
2812 | spin_unlock_irq(&tsk->sighand->siglock); | |
2813 | ||
2b1ecc3d TG |
2814 | __set_current_state(TASK_INTERRUPTIBLE); |
2815 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, | |
2816 | HRTIMER_MODE_REL); | |
943df148 | 2817 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2818 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 2819 | sigemptyset(&tsk->real_blocked); |
b182801a | 2820 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2821 | } |
2822 | spin_unlock_irq(&tsk->sighand->siglock); | |
2823 | ||
2824 | if (sig) | |
2825 | return sig; | |
2b1ecc3d | 2826 | return ret ? -EINTR : -EAGAIN; |
943df148 ON |
2827 | } |
2828 | ||
41c57892 RD |
2829 | /** |
2830 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2831 | * in @uthese | |
2832 | * @uthese: queued signals to wait for | |
2833 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2834 | * @uts: upper bound on process time suspension | |
2835 | * @sigsetsize: size of sigset_t type | |
2836 | */ | |
17da2bd9 HC |
2837 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2838 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2839 | size_t, sigsetsize) | |
1da177e4 | 2840 | { |
1da177e4 LT |
2841 | sigset_t these; |
2842 | struct timespec ts; | |
2843 | siginfo_t info; | |
943df148 | 2844 | int ret; |
1da177e4 LT |
2845 | |
2846 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2847 | if (sigsetsize != sizeof(sigset_t)) | |
2848 | return -EINVAL; | |
2849 | ||
2850 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2851 | return -EFAULT; | |
5aba085e | 2852 | |
1da177e4 LT |
2853 | if (uts) { |
2854 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2855 | return -EFAULT; | |
1da177e4 LT |
2856 | } |
2857 | ||
943df148 | 2858 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2859 | |
943df148 ON |
2860 | if (ret > 0 && uinfo) { |
2861 | if (copy_siginfo_to_user(uinfo, &info)) | |
2862 | ret = -EFAULT; | |
1da177e4 LT |
2863 | } |
2864 | ||
2865 | return ret; | |
2866 | } | |
2867 | ||
41c57892 RD |
2868 | /** |
2869 | * sys_kill - send a signal to a process | |
2870 | * @pid: the PID of the process | |
2871 | * @sig: signal to be sent | |
2872 | */ | |
17da2bd9 | 2873 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2874 | { |
2875 | struct siginfo info; | |
2876 | ||
2877 | info.si_signo = sig; | |
2878 | info.si_errno = 0; | |
2879 | info.si_code = SI_USER; | |
b488893a | 2880 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2881 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2882 | |
2883 | return kill_something_info(sig, &info, pid); | |
2884 | } | |
2885 | ||
30b4ae8a TG |
2886 | static int |
2887 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2888 | { |
1da177e4 | 2889 | struct task_struct *p; |
30b4ae8a | 2890 | int error = -ESRCH; |
1da177e4 | 2891 | |
3547ff3a | 2892 | rcu_read_lock(); |
228ebcbe | 2893 | p = find_task_by_vpid(pid); |
b488893a | 2894 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2895 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2896 | /* |
2897 | * The null signal is a permissions and process existence | |
2898 | * probe. No signal is actually delivered. | |
2899 | */ | |
4a30debf ON |
2900 | if (!error && sig) { |
2901 | error = do_send_sig_info(sig, info, p, false); | |
2902 | /* | |
2903 | * If lock_task_sighand() failed we pretend the task | |
2904 | * dies after receiving the signal. The window is tiny, | |
2905 | * and the signal is private anyway. | |
2906 | */ | |
2907 | if (unlikely(error == -ESRCH)) | |
2908 | error = 0; | |
1da177e4 LT |
2909 | } |
2910 | } | |
3547ff3a | 2911 | rcu_read_unlock(); |
6dd69f10 | 2912 | |
1da177e4 LT |
2913 | return error; |
2914 | } | |
2915 | ||
30b4ae8a TG |
2916 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2917 | { | |
b9e146d8 | 2918 | struct siginfo info = {}; |
30b4ae8a TG |
2919 | |
2920 | info.si_signo = sig; | |
2921 | info.si_errno = 0; | |
2922 | info.si_code = SI_TKILL; | |
2923 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 2924 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
2925 | |
2926 | return do_send_specific(tgid, pid, sig, &info); | |
2927 | } | |
2928 | ||
6dd69f10 VL |
2929 | /** |
2930 | * sys_tgkill - send signal to one specific thread | |
2931 | * @tgid: the thread group ID of the thread | |
2932 | * @pid: the PID of the thread | |
2933 | * @sig: signal to be sent | |
2934 | * | |
72fd4a35 | 2935 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2936 | * exists but it's not belonging to the target process anymore. This |
2937 | * method solves the problem of threads exiting and PIDs getting reused. | |
2938 | */ | |
a5f8fa9e | 2939 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
2940 | { |
2941 | /* This is only valid for single tasks */ | |
2942 | if (pid <= 0 || tgid <= 0) | |
2943 | return -EINVAL; | |
2944 | ||
2945 | return do_tkill(tgid, pid, sig); | |
2946 | } | |
2947 | ||
41c57892 RD |
2948 | /** |
2949 | * sys_tkill - send signal to one specific task | |
2950 | * @pid: the PID of the task | |
2951 | * @sig: signal to be sent | |
2952 | * | |
1da177e4 LT |
2953 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
2954 | */ | |
a5f8fa9e | 2955 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 2956 | { |
1da177e4 LT |
2957 | /* This is only valid for single tasks */ |
2958 | if (pid <= 0) | |
2959 | return -EINVAL; | |
2960 | ||
6dd69f10 | 2961 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2962 | } |
2963 | ||
75907d4d AV |
2964 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) |
2965 | { | |
2966 | /* Not even root can pretend to send signals from the kernel. | |
2967 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
2968 | */ | |
66dd34ad | 2969 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
69828dce | 2970 | (task_pid_vnr(current) != pid)) |
75907d4d | 2971 | return -EPERM; |
69828dce | 2972 | |
75907d4d AV |
2973 | info->si_signo = sig; |
2974 | ||
2975 | /* POSIX.1b doesn't mention process groups. */ | |
2976 | return kill_proc_info(sig, info, pid); | |
2977 | } | |
2978 | ||
41c57892 RD |
2979 | /** |
2980 | * sys_rt_sigqueueinfo - send signal information to a signal | |
2981 | * @pid: the PID of the thread | |
2982 | * @sig: signal to be sent | |
2983 | * @uinfo: signal info to be sent | |
2984 | */ | |
a5f8fa9e HC |
2985 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
2986 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
2987 | { |
2988 | siginfo_t info; | |
1da177e4 LT |
2989 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) |
2990 | return -EFAULT; | |
75907d4d AV |
2991 | return do_rt_sigqueueinfo(pid, sig, &info); |
2992 | } | |
1da177e4 | 2993 | |
75907d4d | 2994 | #ifdef CONFIG_COMPAT |
75907d4d AV |
2995 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
2996 | compat_pid_t, pid, | |
2997 | int, sig, | |
2998 | struct compat_siginfo __user *, uinfo) | |
2999 | { | |
3c00cb5e | 3000 | siginfo_t info = {}; |
75907d4d AV |
3001 | int ret = copy_siginfo_from_user32(&info, uinfo); |
3002 | if (unlikely(ret)) | |
3003 | return ret; | |
3004 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 3005 | } |
75907d4d | 3006 | #endif |
1da177e4 | 3007 | |
9aae8fc0 | 3008 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
62ab4505 TG |
3009 | { |
3010 | /* This is only valid for single tasks */ | |
3011 | if (pid <= 0 || tgid <= 0) | |
3012 | return -EINVAL; | |
3013 | ||
3014 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3015 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3016 | */ | |
69828dce VD |
3017 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3018 | (task_pid_vnr(current) != pid)) | |
62ab4505 | 3019 | return -EPERM; |
69828dce | 3020 | |
62ab4505 TG |
3021 | info->si_signo = sig; |
3022 | ||
3023 | return do_send_specific(tgid, pid, sig, info); | |
3024 | } | |
3025 | ||
3026 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3027 | siginfo_t __user *, uinfo) | |
3028 | { | |
3029 | siginfo_t info; | |
3030 | ||
3031 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3032 | return -EFAULT; | |
3033 | ||
3034 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3035 | } | |
3036 | ||
9aae8fc0 AV |
3037 | #ifdef CONFIG_COMPAT |
3038 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3039 | compat_pid_t, tgid, | |
3040 | compat_pid_t, pid, | |
3041 | int, sig, | |
3042 | struct compat_siginfo __user *, uinfo) | |
3043 | { | |
3c00cb5e | 3044 | siginfo_t info = {}; |
9aae8fc0 AV |
3045 | |
3046 | if (copy_siginfo_from_user32(&info, uinfo)) | |
3047 | return -EFAULT; | |
3048 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3049 | } | |
3050 | #endif | |
3051 | ||
0341729b | 3052 | /* |
b4e74264 | 3053 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
0341729b | 3054 | */ |
b4e74264 | 3055 | void kernel_sigaction(int sig, __sighandler_t action) |
0341729b | 3056 | { |
ec5955b8 | 3057 | spin_lock_irq(¤t->sighand->siglock); |
b4e74264 ON |
3058 | current->sighand->action[sig - 1].sa.sa_handler = action; |
3059 | if (action == SIG_IGN) { | |
3060 | sigset_t mask; | |
0341729b | 3061 | |
b4e74264 ON |
3062 | sigemptyset(&mask); |
3063 | sigaddset(&mask, sig); | |
580d34e4 | 3064 | |
b4e74264 ON |
3065 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
3066 | flush_sigqueue_mask(&mask, ¤t->pending); | |
3067 | recalc_sigpending(); | |
3068 | } | |
0341729b ON |
3069 | spin_unlock_irq(¤t->sighand->siglock); |
3070 | } | |
b4e74264 | 3071 | EXPORT_SYMBOL(kernel_sigaction); |
0341729b | 3072 | |
68463510 DS |
3073 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
3074 | struct k_sigaction *oact) | |
3075 | { | |
3076 | } | |
3077 | ||
88531f72 | 3078 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3079 | { |
afe2b038 | 3080 | struct task_struct *p = current, *t; |
1da177e4 | 3081 | struct k_sigaction *k; |
71fabd5e | 3082 | sigset_t mask; |
1da177e4 | 3083 | |
7ed20e1a | 3084 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3085 | return -EINVAL; |
3086 | ||
afe2b038 | 3087 | k = &p->sighand->action[sig-1]; |
1da177e4 | 3088 | |
afe2b038 | 3089 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
3090 | if (oact) |
3091 | *oact = *k; | |
3092 | ||
68463510 DS |
3093 | sigaction_compat_abi(act, oact); |
3094 | ||
1da177e4 | 3095 | if (act) { |
9ac95f2f ON |
3096 | sigdelsetmask(&act->sa.sa_mask, |
3097 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3098 | *k = *act; |
1da177e4 LT |
3099 | /* |
3100 | * POSIX 3.3.1.3: | |
3101 | * "Setting a signal action to SIG_IGN for a signal that is | |
3102 | * pending shall cause the pending signal to be discarded, | |
3103 | * whether or not it is blocked." | |
3104 | * | |
3105 | * "Setting a signal action to SIG_DFL for a signal that is | |
3106 | * pending and whose default action is to ignore the signal | |
3107 | * (for example, SIGCHLD), shall cause the pending signal to | |
3108 | * be discarded, whether or not it is blocked" | |
3109 | */ | |
afe2b038 | 3110 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
71fabd5e GA |
3111 | sigemptyset(&mask); |
3112 | sigaddset(&mask, sig); | |
afe2b038 ON |
3113 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
3114 | for_each_thread(p, t) | |
c09c1441 | 3115 | flush_sigqueue_mask(&mask, &t->pending); |
1da177e4 | 3116 | } |
1da177e4 LT |
3117 | } |
3118 | ||
afe2b038 | 3119 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
3120 | return 0; |
3121 | } | |
3122 | ||
c09c1441 | 3123 | static int |
1da177e4 LT |
3124 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) |
3125 | { | |
3126 | stack_t oss; | |
3127 | int error; | |
3128 | ||
0083fc2c LT |
3129 | oss.ss_sp = (void __user *) current->sas_ss_sp; |
3130 | oss.ss_size = current->sas_ss_size; | |
0318bc8a AL |
3131 | oss.ss_flags = sas_ss_flags(sp) | |
3132 | (current->sas_ss_flags & SS_FLAG_BITS); | |
1da177e4 LT |
3133 | |
3134 | if (uss) { | |
3135 | void __user *ss_sp; | |
3136 | size_t ss_size; | |
407bc16a SS |
3137 | unsigned ss_flags; |
3138 | int ss_mode; | |
1da177e4 LT |
3139 | |
3140 | error = -EFAULT; | |
0dd8486b LT |
3141 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss))) |
3142 | goto out; | |
3143 | error = __get_user(ss_sp, &uss->ss_sp) | | |
3144 | __get_user(ss_flags, &uss->ss_flags) | | |
3145 | __get_user(ss_size, &uss->ss_size); | |
3146 | if (error) | |
1da177e4 LT |
3147 | goto out; |
3148 | ||
3149 | error = -EPERM; | |
3150 | if (on_sig_stack(sp)) | |
3151 | goto out; | |
3152 | ||
407bc16a | 3153 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
1da177e4 | 3154 | error = -EINVAL; |
407bc16a SS |
3155 | if (ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
3156 | ss_mode != 0) | |
1da177e4 LT |
3157 | goto out; |
3158 | ||
407bc16a | 3159 | if (ss_mode == SS_DISABLE) { |
1da177e4 LT |
3160 | ss_size = 0; |
3161 | ss_sp = NULL; | |
3162 | } else { | |
3163 | error = -ENOMEM; | |
3164 | if (ss_size < MINSIGSTKSZ) | |
3165 | goto out; | |
3166 | } | |
3167 | ||
3168 | current->sas_ss_sp = (unsigned long) ss_sp; | |
3169 | current->sas_ss_size = ss_size; | |
2a742138 | 3170 | current->sas_ss_flags = ss_flags; |
1da177e4 LT |
3171 | } |
3172 | ||
0083fc2c | 3173 | error = 0; |
1da177e4 LT |
3174 | if (uoss) { |
3175 | error = -EFAULT; | |
0083fc2c | 3176 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))) |
1da177e4 | 3177 | goto out; |
0083fc2c LT |
3178 | error = __put_user(oss.ss_sp, &uoss->ss_sp) | |
3179 | __put_user(oss.ss_size, &uoss->ss_size) | | |
3180 | __put_user(oss.ss_flags, &uoss->ss_flags); | |
1da177e4 LT |
3181 | } |
3182 | ||
1da177e4 LT |
3183 | out: |
3184 | return error; | |
3185 | } | |
6bf9adfc AV |
3186 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3187 | { | |
3188 | return do_sigaltstack(uss, uoss, current_user_stack_pointer()); | |
3189 | } | |
1da177e4 | 3190 | |
5c49574f AV |
3191 | int restore_altstack(const stack_t __user *uss) |
3192 | { | |
3193 | int err = do_sigaltstack(uss, NULL, current_user_stack_pointer()); | |
3194 | /* squash all but EFAULT for now */ | |
3195 | return err == -EFAULT ? err : 0; | |
3196 | } | |
3197 | ||
c40702c4 AV |
3198 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3199 | { | |
3200 | struct task_struct *t = current; | |
2a742138 SS |
3201 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
3202 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3203 | __put_user(t->sas_ss_size, &uss->ss_size); |
2a742138 SS |
3204 | if (err) |
3205 | return err; | |
3206 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3207 | sas_ss_reset(t); | |
3208 | return 0; | |
c40702c4 AV |
3209 | } |
3210 | ||
90268439 | 3211 | #ifdef CONFIG_COMPAT |
90228fc1 AV |
3212 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
3213 | const compat_stack_t __user *, uss_ptr, | |
3214 | compat_stack_t __user *, uoss_ptr) | |
90268439 AV |
3215 | { |
3216 | stack_t uss, uoss; | |
3217 | int ret; | |
3218 | mm_segment_t seg; | |
3219 | ||
3220 | if (uss_ptr) { | |
3221 | compat_stack_t uss32; | |
3222 | ||
3223 | memset(&uss, 0, sizeof(stack_t)); | |
3224 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) | |
3225 | return -EFAULT; | |
3226 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
3227 | uss.ss_flags = uss32.ss_flags; | |
3228 | uss.ss_size = uss32.ss_size; | |
3229 | } | |
3230 | seg = get_fs(); | |
3231 | set_fs(KERNEL_DS); | |
3232 | ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), | |
3233 | (stack_t __force __user *) &uoss, | |
3234 | compat_user_stack_pointer()); | |
3235 | set_fs(seg); | |
3236 | if (ret >= 0 && uoss_ptr) { | |
3237 | if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) || | |
3238 | __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) || | |
3239 | __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) || | |
3240 | __put_user(uoss.ss_size, &uoss_ptr->ss_size)) | |
3241 | ret = -EFAULT; | |
3242 | } | |
3243 | return ret; | |
3244 | } | |
3245 | ||
3246 | int compat_restore_altstack(const compat_stack_t __user *uss) | |
3247 | { | |
3248 | int err = compat_sys_sigaltstack(uss, NULL); | |
3249 | /* squash all but -EFAULT for now */ | |
3250 | return err == -EFAULT ? err : 0; | |
3251 | } | |
c40702c4 AV |
3252 | |
3253 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
3254 | { | |
441398d3 | 3255 | int err; |
c40702c4 | 3256 | struct task_struct *t = current; |
441398d3 SS |
3257 | err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
3258 | &uss->ss_sp) | | |
3259 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3260 | __put_user(t->sas_ss_size, &uss->ss_size); |
441398d3 SS |
3261 | if (err) |
3262 | return err; | |
3263 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3264 | sas_ss_reset(t); | |
3265 | return 0; | |
c40702c4 | 3266 | } |
90268439 | 3267 | #endif |
1da177e4 LT |
3268 | |
3269 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3270 | ||
41c57892 RD |
3271 | /** |
3272 | * sys_sigpending - examine pending signals | |
3273 | * @set: where mask of pending signal is returned | |
3274 | */ | |
b290ebe2 | 3275 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 | 3276 | { |
fe9c1db2 | 3277 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); |
1da177e4 LT |
3278 | } |
3279 | ||
3280 | #endif | |
3281 | ||
3282 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3283 | /** |
3284 | * sys_sigprocmask - examine and change blocked signals | |
3285 | * @how: whether to add, remove, or set signals | |
b013c399 | 3286 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3287 | * @oset: previous value of signal mask if non-null |
3288 | * | |
5aba085e RD |
3289 | * Some platforms have their own version with special arguments; |
3290 | * others support only sys_rt_sigprocmask. | |
3291 | */ | |
1da177e4 | 3292 | |
b013c399 | 3293 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3294 | old_sigset_t __user *, oset) |
1da177e4 | 3295 | { |
1da177e4 | 3296 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3297 | sigset_t new_blocked; |
1da177e4 | 3298 | |
b013c399 | 3299 | old_set = current->blocked.sig[0]; |
1da177e4 | 3300 | |
b013c399 ON |
3301 | if (nset) { |
3302 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3303 | return -EFAULT; | |
1da177e4 | 3304 | |
2e4f7c77 | 3305 | new_blocked = current->blocked; |
1da177e4 | 3306 | |
1da177e4 | 3307 | switch (how) { |
1da177e4 | 3308 | case SIG_BLOCK: |
2e4f7c77 | 3309 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3310 | break; |
3311 | case SIG_UNBLOCK: | |
2e4f7c77 | 3312 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3313 | break; |
3314 | case SIG_SETMASK: | |
2e4f7c77 | 3315 | new_blocked.sig[0] = new_set; |
1da177e4 | 3316 | break; |
2e4f7c77 ON |
3317 | default: |
3318 | return -EINVAL; | |
1da177e4 LT |
3319 | } |
3320 | ||
0c4a8423 | 3321 | set_current_blocked(&new_blocked); |
b013c399 ON |
3322 | } |
3323 | ||
3324 | if (oset) { | |
1da177e4 | 3325 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3326 | return -EFAULT; |
1da177e4 | 3327 | } |
b013c399 ON |
3328 | |
3329 | return 0; | |
1da177e4 LT |
3330 | } |
3331 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3332 | ||
eaca6eae | 3333 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
3334 | /** |
3335 | * sys_rt_sigaction - alter an action taken by a process | |
3336 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3337 | * @act: new sigaction |
3338 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3339 | * @sigsetsize: size of sigset_t type |
3340 | */ | |
d4e82042 HC |
3341 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3342 | const struct sigaction __user *, act, | |
3343 | struct sigaction __user *, oact, | |
3344 | size_t, sigsetsize) | |
1da177e4 LT |
3345 | { |
3346 | struct k_sigaction new_sa, old_sa; | |
3347 | int ret = -EINVAL; | |
3348 | ||
3349 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3350 | if (sigsetsize != sizeof(sigset_t)) | |
3351 | goto out; | |
3352 | ||
3353 | if (act) { | |
3354 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3355 | return -EFAULT; | |
3356 | } | |
3357 | ||
3358 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3359 | ||
3360 | if (!ret && oact) { | |
3361 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3362 | return -EFAULT; | |
3363 | } | |
3364 | out: | |
3365 | return ret; | |
3366 | } | |
08d32fe5 | 3367 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
3368 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3369 | const struct compat_sigaction __user *, act, | |
3370 | struct compat_sigaction __user *, oact, | |
3371 | compat_size_t, sigsetsize) | |
3372 | { | |
3373 | struct k_sigaction new_ka, old_ka; | |
3374 | compat_sigset_t mask; | |
3375 | #ifdef __ARCH_HAS_SA_RESTORER | |
3376 | compat_uptr_t restorer; | |
3377 | #endif | |
3378 | int ret; | |
3379 | ||
3380 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3381 | if (sigsetsize != sizeof(compat_sigset_t)) | |
3382 | return -EINVAL; | |
3383 | ||
3384 | if (act) { | |
3385 | compat_uptr_t handler; | |
3386 | ret = get_user(handler, &act->sa_handler); | |
3387 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3388 | #ifdef __ARCH_HAS_SA_RESTORER | |
3389 | ret |= get_user(restorer, &act->sa_restorer); | |
3390 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3391 | #endif | |
3392 | ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask)); | |
3ddc5b46 | 3393 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
3394 | if (ret) |
3395 | return -EFAULT; | |
3396 | sigset_from_compat(&new_ka.sa.sa_mask, &mask); | |
3397 | } | |
3398 | ||
3399 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3400 | if (!ret && oact) { | |
3401 | sigset_to_compat(&mask, &old_ka.sa.sa_mask); | |
3402 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3403 | &oact->sa_handler); | |
3404 | ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask)); | |
3ddc5b46 | 3405 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
3406 | #ifdef __ARCH_HAS_SA_RESTORER |
3407 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3408 | &oact->sa_restorer); | |
3409 | #endif | |
3410 | } | |
3411 | return ret; | |
3412 | } | |
3413 | #endif | |
eaca6eae | 3414 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 3415 | |
495dfbf7 AV |
3416 | #ifdef CONFIG_OLD_SIGACTION |
3417 | SYSCALL_DEFINE3(sigaction, int, sig, | |
3418 | const struct old_sigaction __user *, act, | |
3419 | struct old_sigaction __user *, oact) | |
3420 | { | |
3421 | struct k_sigaction new_ka, old_ka; | |
3422 | int ret; | |
3423 | ||
3424 | if (act) { | |
3425 | old_sigset_t mask; | |
3426 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3427 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
3428 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
3429 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3430 | __get_user(mask, &act->sa_mask)) | |
3431 | return -EFAULT; | |
3432 | #ifdef __ARCH_HAS_KA_RESTORER | |
3433 | new_ka.ka_restorer = NULL; | |
3434 | #endif | |
3435 | siginitset(&new_ka.sa.sa_mask, mask); | |
3436 | } | |
3437 | ||
3438 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3439 | ||
3440 | if (!ret && oact) { | |
3441 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3442 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
3443 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
3444 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3445 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3446 | return -EFAULT; | |
3447 | } | |
3448 | ||
3449 | return ret; | |
3450 | } | |
3451 | #endif | |
3452 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
3453 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
3454 | const struct compat_old_sigaction __user *, act, | |
3455 | struct compat_old_sigaction __user *, oact) | |
3456 | { | |
3457 | struct k_sigaction new_ka, old_ka; | |
3458 | int ret; | |
3459 | compat_old_sigset_t mask; | |
3460 | compat_uptr_t handler, restorer; | |
3461 | ||
3462 | if (act) { | |
3463 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3464 | __get_user(handler, &act->sa_handler) || | |
3465 | __get_user(restorer, &act->sa_restorer) || | |
3466 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3467 | __get_user(mask, &act->sa_mask)) | |
3468 | return -EFAULT; | |
3469 | ||
3470 | #ifdef __ARCH_HAS_KA_RESTORER | |
3471 | new_ka.ka_restorer = NULL; | |
3472 | #endif | |
3473 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3474 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3475 | siginitset(&new_ka.sa.sa_mask, mask); | |
3476 | } | |
3477 | ||
3478 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3479 | ||
3480 | if (!ret && oact) { | |
3481 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3482 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3483 | &oact->sa_handler) || | |
3484 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3485 | &oact->sa_restorer) || | |
3486 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3487 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3488 | return -EFAULT; | |
3489 | } | |
3490 | return ret; | |
3491 | } | |
3492 | #endif | |
1da177e4 | 3493 | |
f6187769 | 3494 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
3495 | |
3496 | /* | |
3497 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3498 | */ | |
a5f8fa9e | 3499 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3500 | { |
3501 | /* SMP safe */ | |
3502 | return current->blocked.sig[0]; | |
3503 | } | |
3504 | ||
a5f8fa9e | 3505 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3506 | { |
c1095c6d ON |
3507 | int old = current->blocked.sig[0]; |
3508 | sigset_t newset; | |
1da177e4 | 3509 | |
5ba53ff6 | 3510 | siginitset(&newset, newmask); |
c1095c6d | 3511 | set_current_blocked(&newset); |
1da177e4 LT |
3512 | |
3513 | return old; | |
3514 | } | |
f6187769 | 3515 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
3516 | |
3517 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3518 | /* | |
3519 | * For backwards compatibility. Functionality superseded by sigaction. | |
3520 | */ | |
a5f8fa9e | 3521 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3522 | { |
3523 | struct k_sigaction new_sa, old_sa; | |
3524 | int ret; | |
3525 | ||
3526 | new_sa.sa.sa_handler = handler; | |
3527 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3528 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3529 | |
3530 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3531 | ||
3532 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3533 | } | |
3534 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3535 | ||
3536 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3537 | ||
a5f8fa9e | 3538 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3539 | { |
d92fcf05 | 3540 | while (!signal_pending(current)) { |
1df01355 | 3541 | __set_current_state(TASK_INTERRUPTIBLE); |
d92fcf05 ON |
3542 | schedule(); |
3543 | } | |
1da177e4 LT |
3544 | return -ERESTARTNOHAND; |
3545 | } | |
3546 | ||
3547 | #endif | |
3548 | ||
9d8a7652 | 3549 | static int sigsuspend(sigset_t *set) |
68f3f16d | 3550 | { |
68f3f16d AV |
3551 | current->saved_sigmask = current->blocked; |
3552 | set_current_blocked(set); | |
3553 | ||
823dd322 SL |
3554 | while (!signal_pending(current)) { |
3555 | __set_current_state(TASK_INTERRUPTIBLE); | |
3556 | schedule(); | |
3557 | } | |
68f3f16d AV |
3558 | set_restore_sigmask(); |
3559 | return -ERESTARTNOHAND; | |
3560 | } | |
68f3f16d | 3561 | |
41c57892 RD |
3562 | /** |
3563 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3564 | * @unewset value until a signal is received | |
3565 | * @unewset: new signal mask value | |
3566 | * @sigsetsize: size of sigset_t type | |
3567 | */ | |
d4e82042 | 3568 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3569 | { |
3570 | sigset_t newset; | |
3571 | ||
3572 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3573 | if (sigsetsize != sizeof(sigset_t)) | |
3574 | return -EINVAL; | |
3575 | ||
3576 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3577 | return -EFAULT; | |
68f3f16d | 3578 | return sigsuspend(&newset); |
150256d8 | 3579 | } |
ad4b65a4 AV |
3580 | |
3581 | #ifdef CONFIG_COMPAT | |
3582 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
3583 | { | |
3584 | #ifdef __BIG_ENDIAN | |
3585 | sigset_t newset; | |
3586 | compat_sigset_t newset32; | |
3587 | ||
3588 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3589 | if (sigsetsize != sizeof(sigset_t)) | |
3590 | return -EINVAL; | |
3591 | ||
3592 | if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t))) | |
3593 | return -EFAULT; | |
3594 | sigset_from_compat(&newset, &newset32); | |
3595 | return sigsuspend(&newset); | |
3596 | #else | |
3597 | /* on little-endian bitmaps don't care about granularity */ | |
3598 | return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize); | |
3599 | #endif | |
3600 | } | |
3601 | #endif | |
150256d8 | 3602 | |
0a0e8cdf AV |
3603 | #ifdef CONFIG_OLD_SIGSUSPEND |
3604 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
3605 | { | |
3606 | sigset_t blocked; | |
3607 | siginitset(&blocked, mask); | |
3608 | return sigsuspend(&blocked); | |
3609 | } | |
3610 | #endif | |
3611 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
3612 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
3613 | { | |
3614 | sigset_t blocked; | |
3615 | siginitset(&blocked, mask); | |
3616 | return sigsuspend(&blocked); | |
3617 | } | |
3618 | #endif | |
150256d8 | 3619 | |
52f5684c | 3620 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
3621 | { |
3622 | return NULL; | |
3623 | } | |
3624 | ||
1da177e4 LT |
3625 | void __init signals_init(void) |
3626 | { | |
41b27154 HD |
3627 | /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */ |
3628 | BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE | |
3629 | != offsetof(struct siginfo, _sifields._pad)); | |
3630 | ||
0a31bd5f | 3631 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3632 | } |
67fc4e0c JW |
3633 | |
3634 | #ifdef CONFIG_KGDB_KDB | |
3635 | #include <linux/kdb.h> | |
3636 | /* | |
3637 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3638 | * signal internals. This function checks if the required locks are | |
3639 | * available before calling the main signal code, to avoid kdb | |
3640 | * deadlocks. | |
3641 | */ | |
3642 | void | |
3643 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3644 | { | |
3645 | static struct task_struct *kdb_prev_t; | |
3646 | int sig, new_t; | |
3647 | if (!spin_trylock(&t->sighand->siglock)) { | |
3648 | kdb_printf("Can't do kill command now.\n" | |
3649 | "The sigmask lock is held somewhere else in " | |
3650 | "kernel, try again later\n"); | |
3651 | return; | |
3652 | } | |
3653 | spin_unlock(&t->sighand->siglock); | |
3654 | new_t = kdb_prev_t != t; | |
3655 | kdb_prev_t = t; | |
3656 | if (t->state != TASK_RUNNING && new_t) { | |
3657 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3658 | "kdb risks deadlock\n" | |
3659 | "on the run queue locks. " | |
3660 | "The signal has _not_ been sent.\n" | |
3661 | "Reissue the kill command if you want to risk " | |
3662 | "the deadlock.\n"); | |
3663 | return; | |
3664 | } | |
3665 | sig = info->si_signo; | |
3666 | if (send_sig_info(sig, info, t)) | |
3667 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3668 | sig, t->pid); | |
3669 | else | |
3670 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3671 | } | |
3672 | #endif /* CONFIG_KGDB_KDB */ |