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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 | 41 | #include <linux/compiler.h> |
31ea70e0 | 42 | #include <linux/posix-timers.h> |
52f5684c | 43 | |
d1eb650f MH |
44 | #define CREATE_TRACE_POINTS |
45 | #include <trace/events/signal.h> | |
84d73786 | 46 | |
1da177e4 | 47 | #include <asm/param.h> |
7c0f6ba6 | 48 | #include <linux/uaccess.h> |
1da177e4 LT |
49 | #include <asm/unistd.h> |
50 | #include <asm/siginfo.h> | |
d550bbd4 | 51 | #include <asm/cacheflush.h> |
e1396065 | 52 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
53 | |
54 | /* | |
55 | * SLAB caches for signal bits. | |
56 | */ | |
57 | ||
e18b890b | 58 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 59 | |
f84d49b2 NO |
60 | int print_fatal_signals __read_mostly; |
61 | ||
35de254d | 62 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 63 | { |
35de254d RM |
64 | return t->sighand->action[sig - 1].sa.sa_handler; |
65 | } | |
93585eea | 66 | |
35de254d RM |
67 | static int sig_handler_ignored(void __user *handler, int sig) |
68 | { | |
93585eea | 69 | /* Is it explicitly or implicitly ignored? */ |
93585eea PE |
70 | return handler == SIG_IGN || |
71 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
72 | } | |
1da177e4 | 73 | |
def8cf72 | 74 | static int sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 75 | { |
35de254d | 76 | void __user *handler; |
1da177e4 | 77 | |
f008faff ON |
78 | handler = sig_handler(t, sig); |
79 | ||
80 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && | |
ac253850 | 81 | handler == SIG_DFL && !(force && sig_kernel_only(sig))) |
f008faff ON |
82 | return 1; |
83 | ||
84 | return sig_handler_ignored(handler, sig); | |
85 | } | |
86 | ||
def8cf72 | 87 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 88 | { |
1da177e4 LT |
89 | /* |
90 | * Blocked signals are never ignored, since the | |
91 | * signal handler may change by the time it is | |
92 | * unblocked. | |
93 | */ | |
325d22df | 94 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
95 | return 0; |
96 | ||
35de254d | 97 | /* |
628c1bcb ON |
98 | * Tracers may want to know about even ignored signal unless it |
99 | * is SIGKILL which can't be reported anyway but can be ignored | |
100 | * by SIGNAL_UNKILLABLE task. | |
35de254d | 101 | */ |
628c1bcb ON |
102 | if (t->ptrace && sig != SIGKILL) |
103 | return 0; | |
104 | ||
105 | return sig_task_ignored(t, sig, force); | |
1da177e4 LT |
106 | } |
107 | ||
108 | /* | |
109 | * Re-calculate pending state from the set of locally pending | |
110 | * signals, globally pending signals, and blocked signals. | |
111 | */ | |
112 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
113 | { | |
114 | unsigned long ready; | |
115 | long i; | |
116 | ||
117 | switch (_NSIG_WORDS) { | |
118 | default: | |
119 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
120 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
121 | break; | |
122 | ||
123 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
124 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
125 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
126 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
127 | break; | |
128 | ||
129 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
130 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
131 | break; | |
132 | ||
133 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
134 | } | |
135 | return ready != 0; | |
136 | } | |
137 | ||
138 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
139 | ||
7bb44ade | 140 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 141 | { |
3759a0d9 | 142 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 143 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 144 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 145 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
146 | return 1; |
147 | } | |
b74d0deb RM |
148 | /* |
149 | * We must never clear the flag in another thread, or in current | |
150 | * when it's possible the current syscall is returning -ERESTART*. | |
151 | * So we don't clear it here, and only callers who know they should do. | |
152 | */ | |
7bb44ade RM |
153 | return 0; |
154 | } | |
155 | ||
156 | /* | |
157 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
158 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
159 | */ | |
160 | void recalc_sigpending_and_wake(struct task_struct *t) | |
161 | { | |
162 | if (recalc_sigpending_tsk(t)) | |
163 | signal_wake_up(t, 0); | |
1da177e4 LT |
164 | } |
165 | ||
166 | void recalc_sigpending(void) | |
167 | { | |
dd1d6772 | 168 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
169 | clear_thread_flag(TIF_SIGPENDING); |
170 | ||
1da177e4 LT |
171 | } |
172 | ||
173 | /* Given the mask, find the first available signal that should be serviced. */ | |
174 | ||
a27341cd LT |
175 | #define SYNCHRONOUS_MASK \ |
176 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 177 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 178 | |
fba2afaa | 179 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
180 | { |
181 | unsigned long i, *s, *m, x; | |
182 | int sig = 0; | |
f84d49b2 | 183 | |
1da177e4 LT |
184 | s = pending->signal.sig; |
185 | m = mask->sig; | |
a27341cd LT |
186 | |
187 | /* | |
188 | * Handle the first word specially: it contains the | |
189 | * synchronous signals that need to be dequeued first. | |
190 | */ | |
191 | x = *s &~ *m; | |
192 | if (x) { | |
193 | if (x & SYNCHRONOUS_MASK) | |
194 | x &= SYNCHRONOUS_MASK; | |
195 | sig = ffz(~x) + 1; | |
196 | return sig; | |
197 | } | |
198 | ||
1da177e4 LT |
199 | switch (_NSIG_WORDS) { |
200 | default: | |
a27341cd LT |
201 | for (i = 1; i < _NSIG_WORDS; ++i) { |
202 | x = *++s &~ *++m; | |
203 | if (!x) | |
204 | continue; | |
205 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
206 | break; | |
207 | } | |
1da177e4 LT |
208 | break; |
209 | ||
a27341cd LT |
210 | case 2: |
211 | x = s[1] &~ m[1]; | |
212 | if (!x) | |
1da177e4 | 213 | break; |
a27341cd | 214 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
215 | break; |
216 | ||
a27341cd LT |
217 | case 1: |
218 | /* Nothing to do */ | |
1da177e4 LT |
219 | break; |
220 | } | |
f84d49b2 | 221 | |
1da177e4 LT |
222 | return sig; |
223 | } | |
224 | ||
f84d49b2 NO |
225 | static inline void print_dropped_signal(int sig) |
226 | { | |
227 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
228 | ||
229 | if (!print_fatal_signals) | |
230 | return; | |
231 | ||
232 | if (!__ratelimit(&ratelimit_state)) | |
233 | return; | |
234 | ||
747800ef | 235 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
f84d49b2 NO |
236 | current->comm, current->pid, sig); |
237 | } | |
238 | ||
d79fdd6d | 239 | /** |
7dd3db54 | 240 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 241 | * @task: target task |
7dd3db54 | 242 | * @mask: pending bits to set |
d79fdd6d | 243 | * |
7dd3db54 TH |
244 | * Clear @mask from @task->jobctl. @mask must be subset of |
245 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
246 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
247 | * cleared. If @task is already being killed or exiting, this function | |
248 | * becomes noop. | |
249 | * | |
250 | * CONTEXT: | |
251 | * Must be called with @task->sighand->siglock held. | |
252 | * | |
253 | * RETURNS: | |
254 | * %true if @mask is set, %false if made noop because @task was dying. | |
255 | */ | |
b76808e6 | 256 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
7dd3db54 TH |
257 | { |
258 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
259 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
260 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
261 | ||
262 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
263 | return false; | |
264 | ||
265 | if (mask & JOBCTL_STOP_SIGMASK) | |
266 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
267 | ||
268 | task->jobctl |= mask; | |
269 | return true; | |
270 | } | |
271 | ||
d79fdd6d | 272 | /** |
a8f072c1 | 273 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
274 | * @task: target task |
275 | * | |
a8f072c1 TH |
276 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
277 | * Clear it and wake up the ptracer. Note that we don't need any further | |
278 | * locking. @task->siglock guarantees that @task->parent points to the | |
279 | * ptracer. | |
d79fdd6d TH |
280 | * |
281 | * CONTEXT: | |
282 | * Must be called with @task->sighand->siglock held. | |
283 | */ | |
73ddff2b | 284 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 285 | { |
a8f072c1 TH |
286 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
287 | task->jobctl &= ~JOBCTL_TRAPPING; | |
650226bd | 288 | smp_mb(); /* advised by wake_up_bit() */ |
62c124ff | 289 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
290 | } |
291 | } | |
292 | ||
e5c1902e | 293 | /** |
3759a0d9 | 294 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 295 | * @task: target task |
3759a0d9 | 296 | * @mask: pending bits to clear |
e5c1902e | 297 | * |
3759a0d9 TH |
298 | * Clear @mask from @task->jobctl. @mask must be subset of |
299 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
300 | * STOP bits are cleared together. | |
e5c1902e | 301 | * |
6dfca329 TH |
302 | * If clearing of @mask leaves no stop or trap pending, this function calls |
303 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
304 | * |
305 | * CONTEXT: | |
306 | * Must be called with @task->sighand->siglock held. | |
307 | */ | |
b76808e6 | 308 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
e5c1902e | 309 | { |
3759a0d9 TH |
310 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
311 | ||
312 | if (mask & JOBCTL_STOP_PENDING) | |
313 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
314 | ||
315 | task->jobctl &= ~mask; | |
6dfca329 TH |
316 | |
317 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
318 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
319 | } |
320 | ||
321 | /** | |
322 | * task_participate_group_stop - participate in a group stop | |
323 | * @task: task participating in a group stop | |
324 | * | |
a8f072c1 | 325 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 326 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 327 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 328 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
329 | * |
330 | * CONTEXT: | |
331 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
332 | * |
333 | * RETURNS: | |
334 | * %true if group stop completion should be notified to the parent, %false | |
335 | * otherwise. | |
e5c1902e TH |
336 | */ |
337 | static bool task_participate_group_stop(struct task_struct *task) | |
338 | { | |
339 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 340 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 341 | |
a8f072c1 | 342 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 343 | |
3759a0d9 | 344 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
345 | |
346 | if (!consume) | |
347 | return false; | |
348 | ||
349 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
350 | sig->group_stop_count--; | |
351 | ||
244056f9 TH |
352 | /* |
353 | * Tell the caller to notify completion iff we are entering into a | |
354 | * fresh group stop. Read comment in do_signal_stop() for details. | |
355 | */ | |
356 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
2d39b3cd | 357 | signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
e5c1902e TH |
358 | return true; |
359 | } | |
360 | return false; | |
361 | } | |
362 | ||
c69e8d9c DH |
363 | /* |
364 | * allocate a new signal queue record | |
365 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 366 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 367 | */ |
f84d49b2 NO |
368 | static struct sigqueue * |
369 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
370 | { |
371 | struct sigqueue *q = NULL; | |
10b1fbdb | 372 | struct user_struct *user; |
1da177e4 | 373 | |
10b1fbdb | 374 | /* |
7cf7db8d TG |
375 | * Protect access to @t credentials. This can go away when all |
376 | * callers hold rcu read lock. | |
10b1fbdb | 377 | */ |
7cf7db8d | 378 | rcu_read_lock(); |
d84f4f99 | 379 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 380 | atomic_inc(&user->sigpending); |
7cf7db8d | 381 | rcu_read_unlock(); |
f84d49b2 | 382 | |
1da177e4 | 383 | if (override_rlimit || |
10b1fbdb | 384 | atomic_read(&user->sigpending) <= |
78d7d407 | 385 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 386 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
387 | } else { |
388 | print_dropped_signal(sig); | |
389 | } | |
390 | ||
1da177e4 | 391 | if (unlikely(q == NULL)) { |
10b1fbdb | 392 | atomic_dec(&user->sigpending); |
d84f4f99 | 393 | free_uid(user); |
1da177e4 LT |
394 | } else { |
395 | INIT_LIST_HEAD(&q->list); | |
396 | q->flags = 0; | |
d84f4f99 | 397 | q->user = user; |
1da177e4 | 398 | } |
d84f4f99 DH |
399 | |
400 | return q; | |
1da177e4 LT |
401 | } |
402 | ||
514a01b8 | 403 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
404 | { |
405 | if (q->flags & SIGQUEUE_PREALLOC) | |
406 | return; | |
407 | atomic_dec(&q->user->sigpending); | |
408 | free_uid(q->user); | |
409 | kmem_cache_free(sigqueue_cachep, q); | |
410 | } | |
411 | ||
6a14c5c9 | 412 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
413 | { |
414 | struct sigqueue *q; | |
415 | ||
416 | sigemptyset(&queue->signal); | |
417 | while (!list_empty(&queue->list)) { | |
418 | q = list_entry(queue->list.next, struct sigqueue , list); | |
419 | list_del_init(&q->list); | |
420 | __sigqueue_free(q); | |
421 | } | |
422 | } | |
423 | ||
424 | /* | |
9e7c8f8c | 425 | * Flush all pending signals for this kthread. |
1da177e4 | 426 | */ |
c81addc9 | 427 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
428 | { |
429 | unsigned long flags; | |
430 | ||
431 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
9e7c8f8c ON |
432 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
433 | flush_sigqueue(&t->pending); | |
434 | flush_sigqueue(&t->signal->shared_pending); | |
1da177e4 LT |
435 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
436 | } | |
437 | ||
baa73d9e | 438 | #ifdef CONFIG_POSIX_TIMERS |
cbaffba1 ON |
439 | static void __flush_itimer_signals(struct sigpending *pending) |
440 | { | |
441 | sigset_t signal, retain; | |
442 | struct sigqueue *q, *n; | |
443 | ||
444 | signal = pending->signal; | |
445 | sigemptyset(&retain); | |
446 | ||
447 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
448 | int sig = q->info.si_signo; | |
449 | ||
450 | if (likely(q->info.si_code != SI_TIMER)) { | |
451 | sigaddset(&retain, sig); | |
452 | } else { | |
453 | sigdelset(&signal, sig); | |
454 | list_del_init(&q->list); | |
455 | __sigqueue_free(q); | |
456 | } | |
457 | } | |
458 | ||
459 | sigorsets(&pending->signal, &signal, &retain); | |
460 | } | |
461 | ||
462 | void flush_itimer_signals(void) | |
463 | { | |
464 | struct task_struct *tsk = current; | |
465 | unsigned long flags; | |
466 | ||
467 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
468 | __flush_itimer_signals(&tsk->pending); | |
469 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
470 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
471 | } | |
baa73d9e | 472 | #endif |
cbaffba1 | 473 | |
10ab825b ON |
474 | void ignore_signals(struct task_struct *t) |
475 | { | |
476 | int i; | |
477 | ||
478 | for (i = 0; i < _NSIG; ++i) | |
479 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
480 | ||
481 | flush_signals(t); | |
482 | } | |
483 | ||
1da177e4 LT |
484 | /* |
485 | * Flush all handlers for a task. | |
486 | */ | |
487 | ||
488 | void | |
489 | flush_signal_handlers(struct task_struct *t, int force_default) | |
490 | { | |
491 | int i; | |
492 | struct k_sigaction *ka = &t->sighand->action[0]; | |
493 | for (i = _NSIG ; i != 0 ; i--) { | |
494 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
495 | ka->sa.sa_handler = SIG_DFL; | |
496 | ka->sa.sa_flags = 0; | |
522cff14 | 497 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
498 | ka->sa.sa_restorer = NULL; |
499 | #endif | |
1da177e4 LT |
500 | sigemptyset(&ka->sa.sa_mask); |
501 | ka++; | |
502 | } | |
503 | } | |
504 | ||
abd4f750 MAS |
505 | int unhandled_signal(struct task_struct *tsk, int sig) |
506 | { | |
445a91d2 | 507 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 508 | if (is_global_init(tsk)) |
abd4f750 | 509 | return 1; |
445a91d2 | 510 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 511 | return 0; |
a288eecc TH |
512 | /* if ptraced, let the tracer determine */ |
513 | return !tsk->ptrace; | |
abd4f750 MAS |
514 | } |
515 | ||
57db7e4a EB |
516 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info, |
517 | bool *resched_timer) | |
1da177e4 LT |
518 | { |
519 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 520 | |
1da177e4 LT |
521 | /* |
522 | * Collect the siginfo appropriate to this signal. Check if | |
523 | * there is another siginfo for the same signal. | |
524 | */ | |
525 | list_for_each_entry(q, &list->list, list) { | |
526 | if (q->info.si_signo == sig) { | |
d4434207 ON |
527 | if (first) |
528 | goto still_pending; | |
1da177e4 LT |
529 | first = q; |
530 | } | |
531 | } | |
d4434207 ON |
532 | |
533 | sigdelset(&list->signal, sig); | |
534 | ||
1da177e4 | 535 | if (first) { |
d4434207 | 536 | still_pending: |
1da177e4 LT |
537 | list_del_init(&first->list); |
538 | copy_siginfo(info, &first->info); | |
57db7e4a EB |
539 | |
540 | *resched_timer = | |
541 | (first->flags & SIGQUEUE_PREALLOC) && | |
542 | (info->si_code == SI_TIMER) && | |
543 | (info->si_sys_private); | |
544 | ||
1da177e4 | 545 | __sigqueue_free(first); |
1da177e4 | 546 | } else { |
5aba085e RD |
547 | /* |
548 | * Ok, it wasn't in the queue. This must be | |
549 | * a fast-pathed signal or we must have been | |
550 | * out of queue space. So zero out the info. | |
1da177e4 | 551 | */ |
1da177e4 LT |
552 | info->si_signo = sig; |
553 | info->si_errno = 0; | |
7486e5d9 | 554 | info->si_code = SI_USER; |
1da177e4 LT |
555 | info->si_pid = 0; |
556 | info->si_uid = 0; | |
557 | } | |
1da177e4 LT |
558 | } |
559 | ||
560 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
57db7e4a | 561 | siginfo_t *info, bool *resched_timer) |
1da177e4 | 562 | { |
27d91e07 | 563 | int sig = next_signal(pending, mask); |
1da177e4 | 564 | |
2e01fabe | 565 | if (sig) |
57db7e4a | 566 | collect_signal(sig, pending, info, resched_timer); |
1da177e4 LT |
567 | return sig; |
568 | } | |
569 | ||
570 | /* | |
5aba085e | 571 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
572 | * expected to free it. |
573 | * | |
574 | * All callers have to hold the siglock. | |
575 | */ | |
576 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
577 | { | |
57db7e4a | 578 | bool resched_timer = false; |
c5363d03 | 579 | int signr; |
caec4e8d BH |
580 | |
581 | /* We only dequeue private signals from ourselves, we don't let | |
582 | * signalfd steal them | |
583 | */ | |
57db7e4a | 584 | signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer); |
8bfd9a7a | 585 | if (!signr) { |
1da177e4 | 586 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
57db7e4a | 587 | mask, info, &resched_timer); |
baa73d9e | 588 | #ifdef CONFIG_POSIX_TIMERS |
8bfd9a7a TG |
589 | /* |
590 | * itimer signal ? | |
591 | * | |
592 | * itimers are process shared and we restart periodic | |
593 | * itimers in the signal delivery path to prevent DoS | |
594 | * attacks in the high resolution timer case. This is | |
5aba085e | 595 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
596 | * itimers, as the SIGALRM is a legacy signal and only |
597 | * queued once. Changing the restart behaviour to | |
598 | * restart the timer in the signal dequeue path is | |
599 | * reducing the timer noise on heavy loaded !highres | |
600 | * systems too. | |
601 | */ | |
602 | if (unlikely(signr == SIGALRM)) { | |
603 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
604 | ||
605 | if (!hrtimer_is_queued(tmr) && | |
2456e855 | 606 | tsk->signal->it_real_incr != 0) { |
8bfd9a7a TG |
607 | hrtimer_forward(tmr, tmr->base->get_time(), |
608 | tsk->signal->it_real_incr); | |
609 | hrtimer_restart(tmr); | |
610 | } | |
611 | } | |
baa73d9e | 612 | #endif |
8bfd9a7a | 613 | } |
c5363d03 | 614 | |
b8fceee1 | 615 | recalc_sigpending(); |
c5363d03 PE |
616 | if (!signr) |
617 | return 0; | |
618 | ||
619 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
620 | /* |
621 | * Set a marker that we have dequeued a stop signal. Our | |
622 | * caller might release the siglock and then the pending | |
623 | * stop signal it is about to process is no longer in the | |
624 | * pending bitmasks, but must still be cleared by a SIGCONT | |
625 | * (and overruled by a SIGKILL). So those cases clear this | |
626 | * shared flag after we've set it. Note that this flag may | |
627 | * remain set after the signal we return is ignored or | |
628 | * handled. That doesn't matter because its only purpose | |
629 | * is to alert stop-signal processing code when another | |
630 | * processor has come along and cleared the flag. | |
631 | */ | |
a8f072c1 | 632 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 633 | } |
baa73d9e | 634 | #ifdef CONFIG_POSIX_TIMERS |
57db7e4a | 635 | if (resched_timer) { |
1da177e4 LT |
636 | /* |
637 | * Release the siglock to ensure proper locking order | |
638 | * of timer locks outside of siglocks. Note, we leave | |
639 | * irqs disabled here, since the posix-timers code is | |
640 | * about to disable them again anyway. | |
641 | */ | |
642 | spin_unlock(&tsk->sighand->siglock); | |
96fe3b07 | 643 | posixtimer_rearm(info); |
1da177e4 LT |
644 | spin_lock(&tsk->sighand->siglock); |
645 | } | |
baa73d9e | 646 | #endif |
1da177e4 LT |
647 | return signr; |
648 | } | |
649 | ||
650 | /* | |
651 | * Tell a process that it has a new active signal.. | |
652 | * | |
653 | * NOTE! we rely on the previous spin_lock to | |
654 | * lock interrupts for us! We can only be called with | |
655 | * "siglock" held, and the local interrupt must | |
656 | * have been disabled when that got acquired! | |
657 | * | |
658 | * No need to set need_resched since signal event passing | |
659 | * goes through ->blocked | |
660 | */ | |
910ffdb1 | 661 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 662 | { |
1da177e4 | 663 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 664 | /* |
910ffdb1 | 665 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 666 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
667 | * executing another processor and just now entering stopped state. |
668 | * By using wake_up_state, we ensure the process will wake up and | |
669 | * handle its death signal. | |
670 | */ | |
910ffdb1 | 671 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
672 | kick_process(t); |
673 | } | |
674 | ||
71fabd5e GA |
675 | /* |
676 | * Remove signals in mask from the pending set and queue. | |
677 | * Returns 1 if any signals were found. | |
678 | * | |
679 | * All callers must be holding the siglock. | |
71fabd5e | 680 | */ |
c09c1441 | 681 | static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
71fabd5e GA |
682 | { |
683 | struct sigqueue *q, *n; | |
684 | sigset_t m; | |
685 | ||
686 | sigandsets(&m, mask, &s->signal); | |
687 | if (sigisemptyset(&m)) | |
688 | return 0; | |
689 | ||
702a5073 | 690 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
691 | list_for_each_entry_safe(q, n, &s->list, list) { |
692 | if (sigismember(mask, q->info.si_signo)) { | |
693 | list_del_init(&q->list); | |
694 | __sigqueue_free(q); | |
695 | } | |
696 | } | |
697 | return 1; | |
698 | } | |
1da177e4 | 699 | |
614c517d ON |
700 | static inline int is_si_special(const struct siginfo *info) |
701 | { | |
702 | return info <= SEND_SIG_FORCED; | |
703 | } | |
704 | ||
705 | static inline bool si_fromuser(const struct siginfo *info) | |
706 | { | |
707 | return info == SEND_SIG_NOINFO || | |
708 | (!is_si_special(info) && SI_FROMUSER(info)); | |
709 | } | |
710 | ||
39fd3393 SH |
711 | /* |
712 | * called with RCU read lock from check_kill_permission() | |
713 | */ | |
714 | static int kill_ok_by_cred(struct task_struct *t) | |
715 | { | |
716 | const struct cred *cred = current_cred(); | |
717 | const struct cred *tcred = __task_cred(t); | |
718 | ||
5af66203 EB |
719 | if (uid_eq(cred->euid, tcred->suid) || |
720 | uid_eq(cred->euid, tcred->uid) || | |
721 | uid_eq(cred->uid, tcred->suid) || | |
722 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
723 | return 1; |
724 | ||
c4a4d603 | 725 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
726 | return 1; |
727 | ||
728 | return 0; | |
729 | } | |
730 | ||
1da177e4 LT |
731 | /* |
732 | * Bad permissions for sending the signal | |
694f690d | 733 | * - the caller must hold the RCU read lock |
1da177e4 LT |
734 | */ |
735 | static int check_kill_permission(int sig, struct siginfo *info, | |
736 | struct task_struct *t) | |
737 | { | |
2e2ba22e | 738 | struct pid *sid; |
3b5e9e53 ON |
739 | int error; |
740 | ||
7ed20e1a | 741 | if (!valid_signal(sig)) |
3b5e9e53 ON |
742 | return -EINVAL; |
743 | ||
614c517d | 744 | if (!si_fromuser(info)) |
3b5e9e53 | 745 | return 0; |
e54dc243 | 746 | |
3b5e9e53 ON |
747 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
748 | if (error) | |
1da177e4 | 749 | return error; |
3b5e9e53 | 750 | |
065add39 | 751 | if (!same_thread_group(current, t) && |
39fd3393 | 752 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
753 | switch (sig) { |
754 | case SIGCONT: | |
2e2ba22e | 755 | sid = task_session(t); |
2e2ba22e ON |
756 | /* |
757 | * We don't return the error if sid == NULL. The | |
758 | * task was unhashed, the caller must notice this. | |
759 | */ | |
760 | if (!sid || sid == task_session(current)) | |
761 | break; | |
762 | default: | |
763 | return -EPERM; | |
764 | } | |
765 | } | |
c2f0c7c3 | 766 | |
e54dc243 | 767 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
768 | } |
769 | ||
fb1d910c TH |
770 | /** |
771 | * ptrace_trap_notify - schedule trap to notify ptracer | |
772 | * @t: tracee wanting to notify tracer | |
773 | * | |
774 | * This function schedules sticky ptrace trap which is cleared on the next | |
775 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
776 | * ptracer. | |
777 | * | |
544b2c91 TH |
778 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
779 | * ptracer is listening for events, tracee is woken up so that it can | |
780 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
781 | * eventually taken without returning to userland after the existing traps | |
782 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
783 | * |
784 | * CONTEXT: | |
785 | * Must be called with @task->sighand->siglock held. | |
786 | */ | |
787 | static void ptrace_trap_notify(struct task_struct *t) | |
788 | { | |
789 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
790 | assert_spin_locked(&t->sighand->siglock); | |
791 | ||
792 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 793 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
794 | } |
795 | ||
1da177e4 | 796 | /* |
7e695a5e ON |
797 | * Handle magic process-wide effects of stop/continue signals. Unlike |
798 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
799 | * time regardless of blocking, ignoring, or handling. This does the |
800 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
801 | * signals. The process stop is done as a signal action for SIG_DFL. |
802 | * | |
803 | * Returns true if the signal should be actually delivered, otherwise | |
804 | * it should be dropped. | |
1da177e4 | 805 | */ |
403bad72 | 806 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 807 | { |
ad16a460 | 808 | struct signal_struct *signal = p->signal; |
1da177e4 | 809 | struct task_struct *t; |
9490592f | 810 | sigset_t flush; |
1da177e4 | 811 | |
403bad72 | 812 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { |
5fa534c9 | 813 | if (!(signal->flags & SIGNAL_GROUP_EXIT)) |
403bad72 | 814 | return sig == SIGKILL; |
1da177e4 | 815 | /* |
7e695a5e | 816 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 817 | */ |
7e695a5e | 818 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
819 | /* |
820 | * This is a stop signal. Remove SIGCONT from all queues. | |
821 | */ | |
9490592f | 822 | siginitset(&flush, sigmask(SIGCONT)); |
c09c1441 | 823 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 824 | for_each_thread(p, t) |
c09c1441 | 825 | flush_sigqueue_mask(&flush, &t->pending); |
1da177e4 | 826 | } else if (sig == SIGCONT) { |
fc321d2e | 827 | unsigned int why; |
1da177e4 | 828 | /* |
1deac632 | 829 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 830 | */ |
9490592f | 831 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
c09c1441 | 832 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 833 | for_each_thread(p, t) { |
c09c1441 | 834 | flush_sigqueue_mask(&flush, &t->pending); |
3759a0d9 | 835 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
fb1d910c TH |
836 | if (likely(!(t->ptrace & PT_SEIZED))) |
837 | wake_up_state(t, __TASK_STOPPED); | |
838 | else | |
839 | ptrace_trap_notify(t); | |
9490592f | 840 | } |
1da177e4 | 841 | |
fc321d2e ON |
842 | /* |
843 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
844 | * | |
845 | * If we were in the middle of a group stop, we pretend it | |
846 | * was already finished, and then continued. Since SIGCHLD | |
847 | * doesn't queue we report only CLD_STOPPED, as if the next | |
848 | * CLD_CONTINUED was dropped. | |
849 | */ | |
850 | why = 0; | |
ad16a460 | 851 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 852 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 853 | else if (signal->group_stop_count) |
fc321d2e ON |
854 | why |= SIGNAL_CLD_STOPPED; |
855 | ||
856 | if (why) { | |
021e1ae3 | 857 | /* |
ae6d2ed7 | 858 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
859 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
860 | * notify its parent. See get_signal_to_deliver(). | |
861 | */ | |
2d39b3cd | 862 | signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
ad16a460 ON |
863 | signal->group_stop_count = 0; |
864 | signal->group_exit_code = 0; | |
1da177e4 | 865 | } |
1da177e4 | 866 | } |
7e695a5e | 867 | |
def8cf72 | 868 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
869 | } |
870 | ||
71f11dc0 ON |
871 | /* |
872 | * Test if P wants to take SIG. After we've checked all threads with this, | |
873 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
874 | * blocking SIG were ruled out because they are not running and already | |
875 | * have pending signals. Such threads will dequeue from the shared queue | |
876 | * as soon as they're available, so putting the signal on the shared queue | |
877 | * will be equivalent to sending it to one such thread. | |
878 | */ | |
879 | static inline int wants_signal(int sig, struct task_struct *p) | |
880 | { | |
881 | if (sigismember(&p->blocked, sig)) | |
882 | return 0; | |
883 | if (p->flags & PF_EXITING) | |
884 | return 0; | |
885 | if (sig == SIGKILL) | |
886 | return 1; | |
887 | if (task_is_stopped_or_traced(p)) | |
888 | return 0; | |
889 | return task_curr(p) || !signal_pending(p); | |
890 | } | |
891 | ||
5fcd835b | 892 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
893 | { |
894 | struct signal_struct *signal = p->signal; | |
895 | struct task_struct *t; | |
896 | ||
897 | /* | |
898 | * Now find a thread we can wake up to take the signal off the queue. | |
899 | * | |
900 | * If the main thread wants the signal, it gets first crack. | |
901 | * Probably the least surprising to the average bear. | |
902 | */ | |
903 | if (wants_signal(sig, p)) | |
904 | t = p; | |
5fcd835b | 905 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
906 | /* |
907 | * There is just one thread and it does not need to be woken. | |
908 | * It will dequeue unblocked signals before it runs again. | |
909 | */ | |
910 | return; | |
911 | else { | |
912 | /* | |
913 | * Otherwise try to find a suitable thread. | |
914 | */ | |
915 | t = signal->curr_target; | |
916 | while (!wants_signal(sig, t)) { | |
917 | t = next_thread(t); | |
918 | if (t == signal->curr_target) | |
919 | /* | |
920 | * No thread needs to be woken. | |
921 | * Any eligible threads will see | |
922 | * the signal in the queue soon. | |
923 | */ | |
924 | return; | |
925 | } | |
926 | signal->curr_target = t; | |
927 | } | |
928 | ||
929 | /* | |
930 | * Found a killable thread. If the signal will be fatal, | |
931 | * then start taking the whole group down immediately. | |
932 | */ | |
fae5fa44 | 933 | if (sig_fatal(p, sig) && |
42691579 | 934 | !(signal->flags & SIGNAL_GROUP_EXIT) && |
71f11dc0 | 935 | !sigismember(&t->real_blocked, sig) && |
42691579 | 936 | (sig == SIGKILL || !p->ptrace)) { |
71f11dc0 ON |
937 | /* |
938 | * This signal will be fatal to the whole group. | |
939 | */ | |
940 | if (!sig_kernel_coredump(sig)) { | |
941 | /* | |
942 | * Start a group exit and wake everybody up. | |
943 | * This way we don't have other threads | |
944 | * running and doing things after a slower | |
945 | * thread has the fatal signal pending. | |
946 | */ | |
947 | signal->flags = SIGNAL_GROUP_EXIT; | |
948 | signal->group_exit_code = sig; | |
949 | signal->group_stop_count = 0; | |
950 | t = p; | |
951 | do { | |
6dfca329 | 952 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
953 | sigaddset(&t->pending.signal, SIGKILL); |
954 | signal_wake_up(t, 1); | |
955 | } while_each_thread(p, t); | |
956 | return; | |
957 | } | |
958 | } | |
959 | ||
960 | /* | |
961 | * The signal is already in the shared-pending queue. | |
962 | * Tell the chosen thread to wake up and dequeue it. | |
963 | */ | |
964 | signal_wake_up(t, sig == SIGKILL); | |
965 | return; | |
966 | } | |
967 | ||
af7fff9c PE |
968 | static inline int legacy_queue(struct sigpending *signals, int sig) |
969 | { | |
970 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
971 | } | |
972 | ||
6b550f94 SH |
973 | #ifdef CONFIG_USER_NS |
974 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
975 | { | |
976 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
977 | return; | |
978 | ||
979 | if (SI_FROMKERNEL(info)) | |
980 | return; | |
981 | ||
078de5f7 EB |
982 | rcu_read_lock(); |
983 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
984 | make_kuid(current_user_ns(), info->si_uid)); | |
985 | rcu_read_unlock(); | |
6b550f94 SH |
986 | } |
987 | #else | |
988 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
989 | { | |
990 | return; | |
991 | } | |
992 | #endif | |
993 | ||
7978b567 SB |
994 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
995 | int group, int from_ancestor_ns) | |
1da177e4 | 996 | { |
2ca3515a | 997 | struct sigpending *pending; |
6e65acba | 998 | struct sigqueue *q; |
7a0aeb14 | 999 | int override_rlimit; |
6c303d3a | 1000 | int ret = 0, result; |
0a16b607 | 1001 | |
6e65acba | 1002 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1003 | |
6c303d3a | 1004 | result = TRACE_SIGNAL_IGNORED; |
629d362b | 1005 | if (!prepare_signal(sig, t, |
3482f6af | 1006 | from_ancestor_ns || (info == SEND_SIG_PRIV) || (info == SEND_SIG_FORCED))) |
6c303d3a | 1007 | goto ret; |
2ca3515a ON |
1008 | |
1009 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
1010 | /* |
1011 | * Short-circuit ignored signals and support queuing | |
1012 | * exactly one non-rt signal, so that we can get more | |
1013 | * detailed information about the cause of the signal. | |
1014 | */ | |
6c303d3a | 1015 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1016 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1017 | goto ret; |
1018 | ||
1019 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1020 | /* |
1021 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1022 | * or SIGKILL. | |
1023 | */ | |
b67a1b9e | 1024 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1025 | goto out_set; |
1026 | ||
5aba085e RD |
1027 | /* |
1028 | * Real-time signals must be queued if sent by sigqueue, or | |
1029 | * some other real-time mechanism. It is implementation | |
1030 | * defined whether kill() does so. We attempt to do so, on | |
1031 | * the principle of least surprise, but since kill is not | |
1032 | * allowed to fail with EAGAIN when low on memory we just | |
1033 | * make sure at least one signal gets delivered and don't | |
1034 | * pass on the info struct. | |
1035 | */ | |
7a0aeb14 VN |
1036 | if (sig < SIGRTMIN) |
1037 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1038 | else | |
1039 | override_rlimit = 0; | |
1040 | ||
75f296d9 | 1041 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit); |
1da177e4 | 1042 | if (q) { |
2ca3515a | 1043 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1044 | switch ((unsigned long) info) { |
b67a1b9e | 1045 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1046 | q->info.si_signo = sig; |
1047 | q->info.si_errno = 0; | |
1048 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1049 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1050 | task_active_pid_ns(t)); |
078de5f7 | 1051 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1052 | break; |
b67a1b9e | 1053 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1054 | q->info.si_signo = sig; |
1055 | q->info.si_errno = 0; | |
1056 | q->info.si_code = SI_KERNEL; | |
1057 | q->info.si_pid = 0; | |
1058 | q->info.si_uid = 0; | |
1059 | break; | |
1060 | default: | |
1061 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1062 | if (from_ancestor_ns) |
1063 | q->info.si_pid = 0; | |
1da177e4 LT |
1064 | break; |
1065 | } | |
6b550f94 SH |
1066 | |
1067 | userns_fixup_signal_uid(&q->info, t); | |
1068 | ||
621d3121 | 1069 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1070 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1071 | /* | |
1072 | * Queue overflow, abort. We may abort if the | |
1073 | * signal was rt and sent by user using something | |
1074 | * other than kill(). | |
1075 | */ | |
6c303d3a ON |
1076 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1077 | ret = -EAGAIN; | |
1078 | goto ret; | |
ba005e1f MH |
1079 | } else { |
1080 | /* | |
1081 | * This is a silent loss of information. We still | |
1082 | * send the signal, but the *info bits are lost. | |
1083 | */ | |
6c303d3a | 1084 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1085 | } |
1da177e4 LT |
1086 | } |
1087 | ||
1088 | out_set: | |
53c30337 | 1089 | signalfd_notify(t, sig); |
2ca3515a | 1090 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1091 | complete_signal(sig, t, group); |
6c303d3a ON |
1092 | ret: |
1093 | trace_signal_generate(sig, info, t, group, result); | |
1094 | return ret; | |
1da177e4 LT |
1095 | } |
1096 | ||
7978b567 SB |
1097 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1098 | int group) | |
1099 | { | |
921cf9f6 SB |
1100 | int from_ancestor_ns = 0; |
1101 | ||
1102 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1103 | from_ancestor_ns = si_fromuser(info) && |
1104 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1105 | #endif |
1106 | ||
1107 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1108 | } |
1109 | ||
4aaefee5 | 1110 | static void print_fatal_signal(int signr) |
45807a1d | 1111 | { |
4aaefee5 | 1112 | struct pt_regs *regs = signal_pt_regs(); |
747800ef | 1113 | pr_info("potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1114 | |
ca5cd877 | 1115 | #if defined(__i386__) && !defined(__arch_um__) |
747800ef | 1116 | pr_info("code at %08lx: ", regs->ip); |
45807a1d IM |
1117 | { |
1118 | int i; | |
1119 | for (i = 0; i < 16; i++) { | |
1120 | unsigned char insn; | |
1121 | ||
b45c6e76 AK |
1122 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1123 | break; | |
747800ef | 1124 | pr_cont("%02x ", insn); |
45807a1d IM |
1125 | } |
1126 | } | |
747800ef | 1127 | pr_cont("\n"); |
45807a1d | 1128 | #endif |
3a9f84d3 | 1129 | preempt_disable(); |
45807a1d | 1130 | show_regs(regs); |
3a9f84d3 | 1131 | preempt_enable(); |
45807a1d IM |
1132 | } |
1133 | ||
1134 | static int __init setup_print_fatal_signals(char *str) | |
1135 | { | |
1136 | get_option (&str, &print_fatal_signals); | |
1137 | ||
1138 | return 1; | |
1139 | } | |
1140 | ||
1141 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1142 | |
4cd4b6d4 PE |
1143 | int |
1144 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1145 | { | |
1146 | return send_signal(sig, info, p, 1); | |
1147 | } | |
1148 | ||
1da177e4 LT |
1149 | static int |
1150 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1151 | { | |
4cd4b6d4 | 1152 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1153 | } |
1154 | ||
4a30debf ON |
1155 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1156 | bool group) | |
1157 | { | |
1158 | unsigned long flags; | |
1159 | int ret = -ESRCH; | |
1160 | ||
1161 | if (lock_task_sighand(p, &flags)) { | |
1162 | ret = send_signal(sig, info, p, group); | |
1163 | unlock_task_sighand(p, &flags); | |
1164 | } | |
1165 | ||
1166 | return ret; | |
1167 | } | |
1168 | ||
1da177e4 LT |
1169 | /* |
1170 | * Force a signal that the process can't ignore: if necessary | |
1171 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1172 | * |
1173 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1174 | * since we do not want to have a signal handler that was blocked | |
1175 | * be invoked when user space had explicitly blocked it. | |
1176 | * | |
80fe728d ON |
1177 | * We don't want to have recursive SIGSEGV's etc, for example, |
1178 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1179 | */ |
1da177e4 LT |
1180 | int |
1181 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1182 | { | |
1183 | unsigned long int flags; | |
ae74c3b6 LT |
1184 | int ret, blocked, ignored; |
1185 | struct k_sigaction *action; | |
1da177e4 LT |
1186 | |
1187 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1188 | action = &t->sighand->action[sig-1]; |
1189 | ignored = action->sa.sa_handler == SIG_IGN; | |
1190 | blocked = sigismember(&t->blocked, sig); | |
1191 | if (blocked || ignored) { | |
1192 | action->sa.sa_handler = SIG_DFL; | |
1193 | if (blocked) { | |
1194 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1195 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1196 | } |
1da177e4 | 1197 | } |
eb61b591 JI |
1198 | /* |
1199 | * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect | |
1200 | * debugging to leave init killable. | |
1201 | */ | |
1202 | if (action->sa.sa_handler == SIG_DFL && !t->ptrace) | |
80fe728d | 1203 | t->signal->flags &= ~SIGNAL_UNKILLABLE; |
1da177e4 LT |
1204 | ret = specific_send_sig_info(sig, info, t); |
1205 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1206 | ||
1207 | return ret; | |
1208 | } | |
1209 | ||
1da177e4 LT |
1210 | /* |
1211 | * Nuke all other threads in the group. | |
1212 | */ | |
09faef11 | 1213 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1214 | { |
09faef11 ON |
1215 | struct task_struct *t = p; |
1216 | int count = 0; | |
1da177e4 | 1217 | |
1da177e4 LT |
1218 | p->signal->group_stop_count = 0; |
1219 | ||
09faef11 | 1220 | while_each_thread(p, t) { |
6dfca329 | 1221 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1222 | count++; |
1223 | ||
1224 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1225 | if (t->exit_state) |
1226 | continue; | |
1da177e4 | 1227 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1228 | signal_wake_up(t, 1); |
1229 | } | |
09faef11 ON |
1230 | |
1231 | return count; | |
1da177e4 LT |
1232 | } |
1233 | ||
b8ed374e NK |
1234 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1235 | unsigned long *flags) | |
f63ee72e ON |
1236 | { |
1237 | struct sighand_struct *sighand; | |
1238 | ||
1239 | for (;;) { | |
c41247e1 PM |
1240 | /* |
1241 | * Disable interrupts early to avoid deadlocks. | |
1242 | * See rcu_read_unlock() comment header for details. | |
1243 | */ | |
a841796f PM |
1244 | local_irq_save(*flags); |
1245 | rcu_read_lock(); | |
f63ee72e | 1246 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1247 | if (unlikely(sighand == NULL)) { |
1248 | rcu_read_unlock(); | |
1249 | local_irq_restore(*flags); | |
f63ee72e | 1250 | break; |
a841796f | 1251 | } |
392809b2 ON |
1252 | /* |
1253 | * This sighand can be already freed and even reused, but | |
5f0d5a3a | 1254 | * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which |
392809b2 ON |
1255 | * initializes ->siglock: this slab can't go away, it has |
1256 | * the same object type, ->siglock can't be reinitialized. | |
1257 | * | |
1258 | * We need to ensure that tsk->sighand is still the same | |
1259 | * after we take the lock, we can race with de_thread() or | |
1260 | * __exit_signal(). In the latter case the next iteration | |
1261 | * must see ->sighand == NULL. | |
1262 | */ | |
a841796f PM |
1263 | spin_lock(&sighand->siglock); |
1264 | if (likely(sighand == tsk->sighand)) { | |
1265 | rcu_read_unlock(); | |
f63ee72e | 1266 | break; |
a841796f PM |
1267 | } |
1268 | spin_unlock(&sighand->siglock); | |
1269 | rcu_read_unlock(); | |
1270 | local_irq_restore(*flags); | |
f63ee72e ON |
1271 | } |
1272 | ||
1273 | return sighand; | |
1274 | } | |
1275 | ||
c69e8d9c DH |
1276 | /* |
1277 | * send signal info to all the members of a group | |
c69e8d9c | 1278 | */ |
1da177e4 LT |
1279 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1280 | { | |
694f690d DH |
1281 | int ret; |
1282 | ||
1283 | rcu_read_lock(); | |
1284 | ret = check_kill_permission(sig, info, p); | |
1285 | rcu_read_unlock(); | |
f63ee72e | 1286 | |
4a30debf ON |
1287 | if (!ret && sig) |
1288 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1289 | |
1290 | return ret; | |
1291 | } | |
1292 | ||
1293 | /* | |
146a505d | 1294 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1295 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1296 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1297 | */ |
c4b92fc1 | 1298 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1299 | { |
1300 | struct task_struct *p = NULL; | |
1301 | int retval, success; | |
1302 | ||
1da177e4 LT |
1303 | success = 0; |
1304 | retval = -ESRCH; | |
c4b92fc1 | 1305 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1306 | int err = group_send_sig_info(sig, info, p); |
1307 | success |= !err; | |
1308 | retval = err; | |
c4b92fc1 | 1309 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1310 | return success ? 0 : retval; |
1311 | } | |
1312 | ||
c4b92fc1 | 1313 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1314 | { |
d36174bc | 1315 | int error = -ESRCH; |
1da177e4 LT |
1316 | struct task_struct *p; |
1317 | ||
eca1a089 PM |
1318 | for (;;) { |
1319 | rcu_read_lock(); | |
1320 | p = pid_task(pid, PIDTYPE_PID); | |
1321 | if (p) | |
1322 | error = group_send_sig_info(sig, info, p); | |
1323 | rcu_read_unlock(); | |
1324 | if (likely(!p || error != -ESRCH)) | |
1325 | return error; | |
6ca25b55 | 1326 | |
eca1a089 PM |
1327 | /* |
1328 | * The task was unhashed in between, try again. If it | |
1329 | * is dead, pid_task() will return NULL, if we race with | |
1330 | * de_thread() it will find the new leader. | |
1331 | */ | |
1332 | } | |
1da177e4 LT |
1333 | } |
1334 | ||
6c478ae9 | 1335 | static int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1336 | { |
1337 | int error; | |
1338 | rcu_read_lock(); | |
b488893a | 1339 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1340 | rcu_read_unlock(); |
1341 | return error; | |
1342 | } | |
1343 | ||
d178bc3a SH |
1344 | static int kill_as_cred_perm(const struct cred *cred, |
1345 | struct task_struct *target) | |
1346 | { | |
1347 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1348 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1349 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1350 | return 0; |
1351 | return 1; | |
1352 | } | |
1353 | ||
2425c08b | 1354 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1355 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1356 | const struct cred *cred, u32 secid) | |
46113830 HW |
1357 | { |
1358 | int ret = -EINVAL; | |
1359 | struct task_struct *p; | |
14d8c9f3 | 1360 | unsigned long flags; |
46113830 HW |
1361 | |
1362 | if (!valid_signal(sig)) | |
1363 | return ret; | |
1364 | ||
14d8c9f3 | 1365 | rcu_read_lock(); |
2425c08b | 1366 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1367 | if (!p) { |
1368 | ret = -ESRCH; | |
1369 | goto out_unlock; | |
1370 | } | |
d178bc3a | 1371 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1372 | ret = -EPERM; |
1373 | goto out_unlock; | |
1374 | } | |
8f95dc58 DQ |
1375 | ret = security_task_kill(p, info, sig, secid); |
1376 | if (ret) | |
1377 | goto out_unlock; | |
14d8c9f3 TG |
1378 | |
1379 | if (sig) { | |
1380 | if (lock_task_sighand(p, &flags)) { | |
1381 | ret = __send_signal(sig, info, p, 1, 0); | |
1382 | unlock_task_sighand(p, &flags); | |
1383 | } else | |
1384 | ret = -ESRCH; | |
46113830 HW |
1385 | } |
1386 | out_unlock: | |
14d8c9f3 | 1387 | rcu_read_unlock(); |
46113830 HW |
1388 | return ret; |
1389 | } | |
d178bc3a | 1390 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1391 | |
1392 | /* | |
1393 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1394 | * | |
1395 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1396 | * is probably wrong. Should make it like BSD or SYSV. | |
1397 | */ | |
1398 | ||
bc64efd2 | 1399 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1400 | { |
8d42db18 | 1401 | int ret; |
d5df763b PE |
1402 | |
1403 | if (pid > 0) { | |
1404 | rcu_read_lock(); | |
1405 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1406 | rcu_read_unlock(); | |
1407 | return ret; | |
1408 | } | |
1409 | ||
4ea77014 | 1410 | /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */ |
1411 | if (pid == INT_MIN) | |
1412 | return -ESRCH; | |
1413 | ||
d5df763b PE |
1414 | read_lock(&tasklist_lock); |
1415 | if (pid != -1) { | |
1416 | ret = __kill_pgrp_info(sig, info, | |
1417 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1418 | } else { | |
1da177e4 LT |
1419 | int retval = 0, count = 0; |
1420 | struct task_struct * p; | |
1421 | ||
1da177e4 | 1422 | for_each_process(p) { |
d25141a8 SB |
1423 | if (task_pid_vnr(p) > 1 && |
1424 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1425 | int err = group_send_sig_info(sig, info, p); |
1426 | ++count; | |
1427 | if (err != -EPERM) | |
1428 | retval = err; | |
1429 | } | |
1430 | } | |
8d42db18 | 1431 | ret = count ? retval : -ESRCH; |
1da177e4 | 1432 | } |
d5df763b PE |
1433 | read_unlock(&tasklist_lock); |
1434 | ||
8d42db18 | 1435 | return ret; |
1da177e4 LT |
1436 | } |
1437 | ||
1438 | /* | |
1439 | * These are for backward compatibility with the rest of the kernel source. | |
1440 | */ | |
1441 | ||
5aba085e | 1442 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1443 | { |
1da177e4 LT |
1444 | /* |
1445 | * Make sure legacy kernel users don't send in bad values | |
1446 | * (normal paths check this in check_kill_permission). | |
1447 | */ | |
7ed20e1a | 1448 | if (!valid_signal(sig)) |
1da177e4 LT |
1449 | return -EINVAL; |
1450 | ||
4a30debf | 1451 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1452 | } |
1453 | ||
b67a1b9e ON |
1454 | #define __si_special(priv) \ |
1455 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1456 | ||
1da177e4 LT |
1457 | int |
1458 | send_sig(int sig, struct task_struct *p, int priv) | |
1459 | { | |
b67a1b9e | 1460 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1461 | } |
1462 | ||
1da177e4 LT |
1463 | void |
1464 | force_sig(int sig, struct task_struct *p) | |
1465 | { | |
b67a1b9e | 1466 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1467 | } |
1468 | ||
1469 | /* | |
1470 | * When things go south during signal handling, we | |
1471 | * will force a SIGSEGV. And if the signal that caused | |
1472 | * the problem was already a SIGSEGV, we'll want to | |
1473 | * make sure we don't even try to deliver the signal.. | |
1474 | */ | |
1475 | int | |
1476 | force_sigsegv(int sig, struct task_struct *p) | |
1477 | { | |
1478 | if (sig == SIGSEGV) { | |
1479 | unsigned long flags; | |
1480 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1481 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1482 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1483 | } | |
1484 | force_sig(SIGSEGV, p); | |
1485 | return 0; | |
1486 | } | |
1487 | ||
c4b92fc1 EB |
1488 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1489 | { | |
146a505d PE |
1490 | int ret; |
1491 | ||
1492 | read_lock(&tasklist_lock); | |
1493 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1494 | read_unlock(&tasklist_lock); | |
1495 | ||
1496 | return ret; | |
c4b92fc1 EB |
1497 | } |
1498 | EXPORT_SYMBOL(kill_pgrp); | |
1499 | ||
1500 | int kill_pid(struct pid *pid, int sig, int priv) | |
1501 | { | |
1502 | return kill_pid_info(sig, __si_special(priv), pid); | |
1503 | } | |
1504 | EXPORT_SYMBOL(kill_pid); | |
1505 | ||
1da177e4 LT |
1506 | /* |
1507 | * These functions support sending signals using preallocated sigqueue | |
1508 | * structures. This is needed "because realtime applications cannot | |
1509 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1510 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1511 | * we allocate the sigqueue structure from the timer_create. If this |
1512 | * allocation fails we are able to report the failure to the application | |
1513 | * with an EAGAIN error. | |
1514 | */ | |
1da177e4 LT |
1515 | struct sigqueue *sigqueue_alloc(void) |
1516 | { | |
f84d49b2 | 1517 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1518 | |
f84d49b2 | 1519 | if (q) |
1da177e4 | 1520 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1521 | |
1522 | return q; | |
1da177e4 LT |
1523 | } |
1524 | ||
1525 | void sigqueue_free(struct sigqueue *q) | |
1526 | { | |
1527 | unsigned long flags; | |
60187d27 ON |
1528 | spinlock_t *lock = ¤t->sighand->siglock; |
1529 | ||
1da177e4 LT |
1530 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1531 | /* | |
c8e85b4f ON |
1532 | * We must hold ->siglock while testing q->list |
1533 | * to serialize with collect_signal() or with | |
da7978b0 | 1534 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1535 | */ |
60187d27 | 1536 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1537 | q->flags &= ~SIGQUEUE_PREALLOC; |
1538 | /* | |
1539 | * If it is queued it will be freed when dequeued, | |
1540 | * like the "regular" sigqueue. | |
1541 | */ | |
60187d27 | 1542 | if (!list_empty(&q->list)) |
c8e85b4f | 1543 | q = NULL; |
60187d27 ON |
1544 | spin_unlock_irqrestore(lock, flags); |
1545 | ||
c8e85b4f ON |
1546 | if (q) |
1547 | __sigqueue_free(q); | |
1da177e4 LT |
1548 | } |
1549 | ||
ac5c2153 | 1550 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1551 | { |
e62e6650 | 1552 | int sig = q->info.si_signo; |
2ca3515a | 1553 | struct sigpending *pending; |
e62e6650 | 1554 | unsigned long flags; |
163566f6 | 1555 | int ret, result; |
2ca3515a | 1556 | |
4cd4b6d4 | 1557 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1558 | |
1559 | ret = -1; | |
1560 | if (!likely(lock_task_sighand(t, &flags))) | |
1561 | goto ret; | |
1562 | ||
7e695a5e | 1563 | ret = 1; /* the signal is ignored */ |
163566f6 | 1564 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1565 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1566 | goto out; |
1567 | ||
1568 | ret = 0; | |
9e3bd6c3 PE |
1569 | if (unlikely(!list_empty(&q->list))) { |
1570 | /* | |
1571 | * If an SI_TIMER entry is already queue just increment | |
1572 | * the overrun count. | |
1573 | */ | |
9e3bd6c3 PE |
1574 | BUG_ON(q->info.si_code != SI_TIMER); |
1575 | q->info.si_overrun++; | |
163566f6 | 1576 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1577 | goto out; |
9e3bd6c3 | 1578 | } |
ba661292 | 1579 | q->info.si_overrun = 0; |
9e3bd6c3 | 1580 | |
9e3bd6c3 | 1581 | signalfd_notify(t, sig); |
2ca3515a | 1582 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1583 | list_add_tail(&q->list, &pending->list); |
1584 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1585 | complete_signal(sig, t, group); |
163566f6 | 1586 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1587 | out: |
163566f6 | 1588 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1589 | unlock_task_sighand(t, &flags); |
1590 | ret: | |
1591 | return ret; | |
9e3bd6c3 PE |
1592 | } |
1593 | ||
1da177e4 LT |
1594 | /* |
1595 | * Let a parent know about the death of a child. | |
1596 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1597 | * |
53c8f9f1 ON |
1598 | * Returns true if our parent ignored us and so we've switched to |
1599 | * self-reaping. | |
1da177e4 | 1600 | */ |
53c8f9f1 | 1601 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1602 | { |
1603 | struct siginfo info; | |
1604 | unsigned long flags; | |
1605 | struct sighand_struct *psig; | |
53c8f9f1 | 1606 | bool autoreap = false; |
bde8285e | 1607 | u64 utime, stime; |
1da177e4 LT |
1608 | |
1609 | BUG_ON(sig == -1); | |
1610 | ||
1611 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1612 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1613 | |
d21142ec | 1614 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1615 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1616 | ||
b6e238dc ON |
1617 | if (sig != SIGCHLD) { |
1618 | /* | |
1619 | * This is only possible if parent == real_parent. | |
1620 | * Check if it has changed security domain. | |
1621 | */ | |
1622 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1623 | sig = SIGCHLD; | |
1624 | } | |
1625 | ||
1da177e4 LT |
1626 | info.si_signo = sig; |
1627 | info.si_errno = 0; | |
b488893a | 1628 | /* |
32084504 EB |
1629 | * We are under tasklist_lock here so our parent is tied to |
1630 | * us and cannot change. | |
b488893a | 1631 | * |
32084504 EB |
1632 | * task_active_pid_ns will always return the same pid namespace |
1633 | * until a task passes through release_task. | |
b488893a PE |
1634 | * |
1635 | * write_lock() currently calls preempt_disable() which is the | |
1636 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1637 | * correct to rely on this | |
1638 | */ | |
1639 | rcu_read_lock(); | |
32084504 | 1640 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1641 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1642 | task_uid(tsk)); | |
b488893a PE |
1643 | rcu_read_unlock(); |
1644 | ||
bde8285e FW |
1645 | task_cputime(tsk, &utime, &stime); |
1646 | info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); | |
1647 | info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1648 | |
1649 | info.si_status = tsk->exit_code & 0x7f; | |
1650 | if (tsk->exit_code & 0x80) | |
1651 | info.si_code = CLD_DUMPED; | |
1652 | else if (tsk->exit_code & 0x7f) | |
1653 | info.si_code = CLD_KILLED; | |
1654 | else { | |
1655 | info.si_code = CLD_EXITED; | |
1656 | info.si_status = tsk->exit_code >> 8; | |
1657 | } | |
1658 | ||
1659 | psig = tsk->parent->sighand; | |
1660 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1661 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1662 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1663 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1664 | /* | |
1665 | * We are exiting and our parent doesn't care. POSIX.1 | |
1666 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1667 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1668 | * automatically and not left for our parent's wait4 call. | |
1669 | * Rather than having the parent do it as a magic kind of | |
1670 | * signal handler, we just set this to tell do_exit that we | |
1671 | * can be cleaned up without becoming a zombie. Note that | |
1672 | * we still call __wake_up_parent in this case, because a | |
1673 | * blocked sys_wait4 might now return -ECHILD. | |
1674 | * | |
1675 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1676 | * is implementation-defined: we do (if you don't want | |
1677 | * it, just use SIG_IGN instead). | |
1678 | */ | |
53c8f9f1 | 1679 | autoreap = true; |
1da177e4 | 1680 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1681 | sig = 0; |
1da177e4 | 1682 | } |
53c8f9f1 | 1683 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1684 | __group_send_sig_info(sig, &info, tsk->parent); |
1685 | __wake_up_parent(tsk, tsk->parent); | |
1686 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1687 | |
53c8f9f1 | 1688 | return autoreap; |
1da177e4 LT |
1689 | } |
1690 | ||
75b95953 TH |
1691 | /** |
1692 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1693 | * @tsk: task reporting the state change | |
1694 | * @for_ptracer: the notification is for ptracer | |
1695 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1696 | * | |
1697 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1698 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1699 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1700 | * | |
1701 | * CONTEXT: | |
1702 | * Must be called with tasklist_lock at least read locked. | |
1703 | */ | |
1704 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1705 | bool for_ptracer, int why) | |
1da177e4 LT |
1706 | { |
1707 | struct siginfo info; | |
1708 | unsigned long flags; | |
bc505a47 | 1709 | struct task_struct *parent; |
1da177e4 | 1710 | struct sighand_struct *sighand; |
bde8285e | 1711 | u64 utime, stime; |
1da177e4 | 1712 | |
75b95953 | 1713 | if (for_ptracer) { |
bc505a47 | 1714 | parent = tsk->parent; |
75b95953 | 1715 | } else { |
bc505a47 ON |
1716 | tsk = tsk->group_leader; |
1717 | parent = tsk->real_parent; | |
1718 | } | |
1719 | ||
1da177e4 LT |
1720 | info.si_signo = SIGCHLD; |
1721 | info.si_errno = 0; | |
b488893a | 1722 | /* |
5aba085e | 1723 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1724 | */ |
1725 | rcu_read_lock(); | |
17cf22c3 | 1726 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1727 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1728 | rcu_read_unlock(); |
1729 | ||
bde8285e FW |
1730 | task_cputime(tsk, &utime, &stime); |
1731 | info.si_utime = nsec_to_clock_t(utime); | |
1732 | info.si_stime = nsec_to_clock_t(stime); | |
1da177e4 LT |
1733 | |
1734 | info.si_code = why; | |
1735 | switch (why) { | |
1736 | case CLD_CONTINUED: | |
1737 | info.si_status = SIGCONT; | |
1738 | break; | |
1739 | case CLD_STOPPED: | |
1740 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1741 | break; | |
1742 | case CLD_TRAPPED: | |
1743 | info.si_status = tsk->exit_code & 0x7f; | |
1744 | break; | |
1745 | default: | |
1746 | BUG(); | |
1747 | } | |
1748 | ||
1749 | sighand = parent->sighand; | |
1750 | spin_lock_irqsave(&sighand->siglock, flags); | |
1751 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1752 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1753 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1754 | /* | |
1755 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1756 | */ | |
1757 | __wake_up_parent(tsk, parent); | |
1758 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1759 | } | |
1760 | ||
d5f70c00 ON |
1761 | static inline int may_ptrace_stop(void) |
1762 | { | |
d21142ec | 1763 | if (!likely(current->ptrace)) |
d5f70c00 | 1764 | return 0; |
d5f70c00 ON |
1765 | /* |
1766 | * Are we in the middle of do_coredump? | |
1767 | * If so and our tracer is also part of the coredump stopping | |
1768 | * is a deadlock situation, and pointless because our tracer | |
1769 | * is dead so don't allow us to stop. | |
1770 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1771 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1772 | * is safe to enter schedule(). |
9899d11f ON |
1773 | * |
1774 | * This is almost outdated, a task with the pending SIGKILL can't | |
1775 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1776 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1777 | */ |
999d9fc1 | 1778 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1779 | unlikely(current->mm == current->parent->mm)) |
1780 | return 0; | |
1781 | ||
1782 | return 1; | |
1783 | } | |
1784 | ||
1a669c2f | 1785 | /* |
5aba085e | 1786 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1787 | * Called with the siglock held. |
1788 | */ | |
1789 | static int sigkill_pending(struct task_struct *tsk) | |
1790 | { | |
3d749b9e ON |
1791 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1792 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1793 | } |
1794 | ||
1da177e4 LT |
1795 | /* |
1796 | * This must be called with current->sighand->siglock held. | |
1797 | * | |
1798 | * This should be the path for all ptrace stops. | |
1799 | * We always set current->last_siginfo while stopped here. | |
1800 | * That makes it a way to test a stopped process for | |
1801 | * being ptrace-stopped vs being job-control-stopped. | |
1802 | * | |
20686a30 ON |
1803 | * If we actually decide not to stop at all because the tracer |
1804 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1805 | */ |
fe1bc6a0 | 1806 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1807 | __releases(¤t->sighand->siglock) |
1808 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1809 | { |
ceb6bd67 TH |
1810 | bool gstop_done = false; |
1811 | ||
1a669c2f RM |
1812 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1813 | /* | |
1814 | * The arch code has something special to do before a | |
1815 | * ptrace stop. This is allowed to block, e.g. for faults | |
1816 | * on user stack pages. We can't keep the siglock while | |
1817 | * calling arch_ptrace_stop, so we must release it now. | |
1818 | * To preserve proper semantics, we must do this before | |
1819 | * any signal bookkeeping like checking group_stop_count. | |
1820 | * Meanwhile, a SIGKILL could come in before we retake the | |
1821 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1822 | * So after regaining the lock, we must check for SIGKILL. | |
1823 | */ | |
1824 | spin_unlock_irq(¤t->sighand->siglock); | |
1825 | arch_ptrace_stop(exit_code, info); | |
1826 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1827 | if (sigkill_pending(current)) |
1828 | return; | |
1a669c2f RM |
1829 | } |
1830 | ||
ea19cfd1 PZ |
1831 | set_special_state(TASK_TRACED); |
1832 | ||
1da177e4 | 1833 | /* |
81be24b8 TH |
1834 | * We're committing to trapping. TRACED should be visible before |
1835 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1836 | * Also, transition to TRACED and updates to ->jobctl should be | |
1837 | * atomic with respect to siglock and should be done after the arch | |
1838 | * hook as siglock is released and regrabbed across it. | |
ea19cfd1 PZ |
1839 | * |
1840 | * TRACER TRACEE | |
1841 | * | |
1842 | * ptrace_attach() | |
1843 | * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED) | |
1844 | * do_wait() | |
1845 | * set_current_state() smp_wmb(); | |
1846 | * ptrace_do_wait() | |
1847 | * wait_task_stopped() | |
1848 | * task_stopped_code() | |
1849 | * [L] task_is_traced() [S] task_clear_jobctl_trapping(); | |
1da177e4 | 1850 | */ |
ea19cfd1 | 1851 | smp_wmb(); |
1da177e4 LT |
1852 | |
1853 | current->last_siginfo = info; | |
1854 | current->exit_code = exit_code; | |
1855 | ||
d79fdd6d | 1856 | /* |
0ae8ce1c TH |
1857 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1858 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1859 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1860 | * could be clear now. We act as if SIGCONT is received after | |
1861 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1862 | */ |
a8f072c1 | 1863 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1864 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1865 | |
fb1d910c | 1866 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1867 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1868 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1869 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1870 | |
81be24b8 | 1871 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1872 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1873 | |
1da177e4 LT |
1874 | spin_unlock_irq(¤t->sighand->siglock); |
1875 | read_lock(&tasklist_lock); | |
3d749b9e | 1876 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1877 | /* |
1878 | * Notify parents of the stop. | |
1879 | * | |
1880 | * While ptraced, there are two parents - the ptracer and | |
1881 | * the real_parent of the group_leader. The ptracer should | |
1882 | * know about every stop while the real parent is only | |
1883 | * interested in the completion of group stop. The states | |
1884 | * for the two don't interact with each other. Notify | |
1885 | * separately unless they're gonna be duplicates. | |
1886 | */ | |
1887 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1888 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1889 | do_notify_parent_cldstop(current, false, why); |
1890 | ||
53da1d94 MS |
1891 | /* |
1892 | * Don't want to allow preemption here, because | |
1893 | * sys_ptrace() needs this task to be inactive. | |
1894 | * | |
1895 | * XXX: implement read_unlock_no_resched(). | |
1896 | */ | |
1897 | preempt_disable(); | |
1da177e4 | 1898 | read_unlock(&tasklist_lock); |
53da1d94 | 1899 | preempt_enable_no_resched(); |
5d8f72b5 | 1900 | freezable_schedule(); |
1da177e4 LT |
1901 | } else { |
1902 | /* | |
1903 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1904 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1905 | * |
1906 | * If @gstop_done, the ptracer went away between group stop | |
1907 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1908 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1909 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1910 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1911 | */ |
ceb6bd67 TH |
1912 | if (gstop_done) |
1913 | do_notify_parent_cldstop(current, false, why); | |
1914 | ||
9899d11f | 1915 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 1916 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1917 | if (clear_code) |
1918 | current->exit_code = 0; | |
6405f7f4 | 1919 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1920 | } |
1921 | ||
1922 | /* | |
1923 | * We are back. Now reacquire the siglock before touching | |
1924 | * last_siginfo, so that we are sure to have synchronized with | |
1925 | * any signal-sending on another CPU that wants to examine it. | |
1926 | */ | |
1927 | spin_lock_irq(¤t->sighand->siglock); | |
1928 | current->last_siginfo = NULL; | |
1929 | ||
544b2c91 TH |
1930 | /* LISTENING can be set only during STOP traps, clear it */ |
1931 | current->jobctl &= ~JOBCTL_LISTENING; | |
1932 | ||
1da177e4 LT |
1933 | /* |
1934 | * Queued signals ignored us while we were stopped for tracing. | |
1935 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1936 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1937 | */ |
b74d0deb | 1938 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1939 | } |
1940 | ||
3544d72a | 1941 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1942 | { |
1943 | siginfo_t info; | |
1944 | ||
1da177e4 | 1945 | memset(&info, 0, sizeof info); |
3544d72a | 1946 | info.si_signo = signr; |
1da177e4 | 1947 | info.si_code = exit_code; |
b488893a | 1948 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 1949 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
1950 | |
1951 | /* Let the debugger run. */ | |
3544d72a TH |
1952 | ptrace_stop(exit_code, why, 1, &info); |
1953 | } | |
1954 | ||
1955 | void ptrace_notify(int exit_code) | |
1956 | { | |
1957 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
1958 | if (unlikely(current->task_works)) |
1959 | task_work_run(); | |
3544d72a | 1960 | |
1da177e4 | 1961 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 1962 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
1963 | spin_unlock_irq(¤t->sighand->siglock); |
1964 | } | |
1965 | ||
73ddff2b TH |
1966 | /** |
1967 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
1968 | * @signr: signr causing group stop if initiating | |
1969 | * | |
1970 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
1971 | * and participate in it. If already set, participate in the existing | |
1972 | * group stop. If participated in a group stop (and thus slept), %true is | |
1973 | * returned with siglock released. | |
1974 | * | |
1975 | * If ptraced, this function doesn't handle stop itself. Instead, | |
1976 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
1977 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
1978 | * places afterwards. | |
1979 | * | |
1980 | * CONTEXT: | |
1981 | * Must be called with @current->sighand->siglock held, which is released | |
1982 | * on %true return. | |
1983 | * | |
1984 | * RETURNS: | |
1985 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
1986 | * %true if participated in group stop. | |
1da177e4 | 1987 | */ |
73ddff2b TH |
1988 | static bool do_signal_stop(int signr) |
1989 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
1990 | { |
1991 | struct signal_struct *sig = current->signal; | |
1da177e4 | 1992 | |
a8f072c1 | 1993 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
b76808e6 | 1994 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
f558b7e4 ON |
1995 | struct task_struct *t; |
1996 | ||
a8f072c1 TH |
1997 | /* signr will be recorded in task->jobctl for retries */ |
1998 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 1999 | |
a8f072c1 | 2000 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 2001 | unlikely(signal_group_exit(sig))) |
73ddff2b | 2002 | return false; |
1da177e4 | 2003 | /* |
408a37de TH |
2004 | * There is no group stop already in progress. We must |
2005 | * initiate one now. | |
2006 | * | |
2007 | * While ptraced, a task may be resumed while group stop is | |
2008 | * still in effect and then receive a stop signal and | |
2009 | * initiate another group stop. This deviates from the | |
2010 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2011 | * cause two group stops when !ptraced. That is why we |
2012 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2013 | * |
2014 | * The condition can be distinguished by testing whether | |
2015 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2016 | * group_exit_code in such case. | |
2017 | * | |
2018 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2019 | * an intervening stop signal is required to cause two | |
2020 | * continued events regardless of ptrace. | |
1da177e4 | 2021 | */ |
408a37de TH |
2022 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2023 | sig->group_exit_code = signr; | |
1da177e4 | 2024 | |
7dd3db54 TH |
2025 | sig->group_stop_count = 0; |
2026 | ||
2027 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2028 | sig->group_stop_count++; | |
1da177e4 | 2029 | |
8d38f203 ON |
2030 | t = current; |
2031 | while_each_thread(current, t) { | |
1da177e4 | 2032 | /* |
a122b341 ON |
2033 | * Setting state to TASK_STOPPED for a group |
2034 | * stop is always done with the siglock held, | |
2035 | * so this check has no races. | |
1da177e4 | 2036 | */ |
7dd3db54 TH |
2037 | if (!task_is_stopped(t) && |
2038 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2039 | sig->group_stop_count++; |
fb1d910c TH |
2040 | if (likely(!(t->ptrace & PT_SEIZED))) |
2041 | signal_wake_up(t, 0); | |
2042 | else | |
2043 | ptrace_trap_notify(t); | |
a122b341 | 2044 | } |
d79fdd6d | 2045 | } |
1da177e4 | 2046 | } |
73ddff2b | 2047 | |
d21142ec | 2048 | if (likely(!current->ptrace)) { |
5224fa36 | 2049 | int notify = 0; |
1da177e4 | 2050 | |
5224fa36 TH |
2051 | /* |
2052 | * If there are no other threads in the group, or if there | |
2053 | * is a group stop in progress and we are the last to stop, | |
2054 | * report to the parent. | |
2055 | */ | |
2056 | if (task_participate_group_stop(current)) | |
2057 | notify = CLD_STOPPED; | |
2058 | ||
ea19cfd1 | 2059 | set_special_state(TASK_STOPPED); |
5224fa36 TH |
2060 | spin_unlock_irq(¤t->sighand->siglock); |
2061 | ||
62bcf9d9 TH |
2062 | /* |
2063 | * Notify the parent of the group stop completion. Because | |
2064 | * we're not holding either the siglock or tasklist_lock | |
2065 | * here, ptracer may attach inbetween; however, this is for | |
2066 | * group stop and should always be delivered to the real | |
2067 | * parent of the group leader. The new ptracer will get | |
2068 | * its notification when this task transitions into | |
2069 | * TASK_TRACED. | |
2070 | */ | |
5224fa36 TH |
2071 | if (notify) { |
2072 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2073 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2074 | read_unlock(&tasklist_lock); |
2075 | } | |
2076 | ||
2077 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
5d8f72b5 | 2078 | freezable_schedule(); |
73ddff2b | 2079 | return true; |
d79fdd6d | 2080 | } else { |
73ddff2b TH |
2081 | /* |
2082 | * While ptraced, group stop is handled by STOP trap. | |
2083 | * Schedule it and let the caller deal with it. | |
2084 | */ | |
2085 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2086 | return false; | |
ae6d2ed7 | 2087 | } |
73ddff2b | 2088 | } |
1da177e4 | 2089 | |
73ddff2b TH |
2090 | /** |
2091 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2092 | * | |
3544d72a TH |
2093 | * When PT_SEIZED, it's used for both group stop and explicit |
2094 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2095 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2096 | * the stop signal; otherwise, %SIGTRAP. | |
2097 | * | |
2098 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2099 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2100 | * |
2101 | * CONTEXT: | |
2102 | * Must be called with @current->sighand->siglock held, which may be | |
2103 | * released and re-acquired before returning with intervening sleep. | |
2104 | */ | |
2105 | static void do_jobctl_trap(void) | |
2106 | { | |
3544d72a | 2107 | struct signal_struct *signal = current->signal; |
73ddff2b | 2108 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2109 | |
3544d72a TH |
2110 | if (current->ptrace & PT_SEIZED) { |
2111 | if (!signal->group_stop_count && | |
2112 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2113 | signr = SIGTRAP; | |
2114 | WARN_ON_ONCE(!signr); | |
2115 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2116 | CLD_STOPPED); | |
2117 | } else { | |
2118 | WARN_ON_ONCE(!signr); | |
2119 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2120 | current->exit_code = 0; | |
ae6d2ed7 | 2121 | } |
1da177e4 LT |
2122 | } |
2123 | ||
94eb22d5 | 2124 | static int ptrace_signal(int signr, siginfo_t *info) |
18c98b65 | 2125 | { |
8a352418 ON |
2126 | /* |
2127 | * We do not check sig_kernel_stop(signr) but set this marker | |
2128 | * unconditionally because we do not know whether debugger will | |
2129 | * change signr. This flag has no meaning unless we are going | |
2130 | * to stop after return from ptrace_stop(). In this case it will | |
2131 | * be checked in do_signal_stop(), we should only stop if it was | |
2132 | * not cleared by SIGCONT while we were sleeping. See also the | |
2133 | * comment in dequeue_signal(). | |
2134 | */ | |
2135 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2136 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2137 | |
2138 | /* We're back. Did the debugger cancel the sig? */ | |
2139 | signr = current->exit_code; | |
2140 | if (signr == 0) | |
2141 | return signr; | |
2142 | ||
2143 | current->exit_code = 0; | |
2144 | ||
5aba085e RD |
2145 | /* |
2146 | * Update the siginfo structure if the signal has | |
2147 | * changed. If the debugger wanted something | |
2148 | * specific in the siginfo structure then it should | |
2149 | * have updated *info via PTRACE_SETSIGINFO. | |
2150 | */ | |
18c98b65 RM |
2151 | if (signr != info->si_signo) { |
2152 | info->si_signo = signr; | |
2153 | info->si_errno = 0; | |
2154 | info->si_code = SI_USER; | |
6b550f94 | 2155 | rcu_read_lock(); |
18c98b65 | 2156 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2157 | info->si_uid = from_kuid_munged(current_user_ns(), |
2158 | task_uid(current->parent)); | |
6b550f94 | 2159 | rcu_read_unlock(); |
18c98b65 RM |
2160 | } |
2161 | ||
2162 | /* If the (new) signal is now blocked, requeue it. */ | |
2163 | if (sigismember(¤t->blocked, signr)) { | |
2164 | specific_send_sig_info(signr, info, current); | |
2165 | signr = 0; | |
2166 | } | |
2167 | ||
2168 | return signr; | |
2169 | } | |
2170 | ||
828b1f65 | 2171 | int get_signal(struct ksignal *ksig) |
1da177e4 | 2172 | { |
f6b76d4f ON |
2173 | struct sighand_struct *sighand = current->sighand; |
2174 | struct signal_struct *signal = current->signal; | |
2175 | int signr; | |
1da177e4 | 2176 | |
f784e8a7 ON |
2177 | if (unlikely(current->task_works)) |
2178 | task_work_run(); | |
72667028 | 2179 | |
0326f5a9 SD |
2180 | if (unlikely(uprobe_deny_signal())) |
2181 | return 0; | |
2182 | ||
13b1c3d4 | 2183 | /* |
5d8f72b5 ON |
2184 | * Do this once, we can't return to user-mode if freezing() == T. |
2185 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2186 | * thus do not need another check after return. | |
13b1c3d4 | 2187 | */ |
fc558a74 RW |
2188 | try_to_freeze(); |
2189 | ||
5d8f72b5 | 2190 | relock: |
f6b76d4f | 2191 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2192 | /* |
2193 | * Every stopped thread goes here after wakeup. Check to see if | |
2194 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2195 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2196 | */ | |
f6b76d4f | 2197 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2198 | int why; |
2199 | ||
2200 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2201 | why = CLD_CONTINUED; | |
2202 | else | |
2203 | why = CLD_STOPPED; | |
2204 | ||
f6b76d4f | 2205 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2206 | |
ae6d2ed7 | 2207 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2208 | |
ceb6bd67 TH |
2209 | /* |
2210 | * Notify the parent that we're continuing. This event is | |
2211 | * always per-process and doesn't make whole lot of sense | |
2212 | * for ptracers, who shouldn't consume the state via | |
2213 | * wait(2) either, but, for backward compatibility, notify | |
2214 | * the ptracer of the group leader too unless it's gonna be | |
2215 | * a duplicate. | |
2216 | */ | |
edf2ed15 | 2217 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2218 | do_notify_parent_cldstop(current, false, why); |
2219 | ||
bb3696da ON |
2220 | if (ptrace_reparented(current->group_leader)) |
2221 | do_notify_parent_cldstop(current->group_leader, | |
2222 | true, why); | |
edf2ed15 | 2223 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2224 | |
e4420551 ON |
2225 | goto relock; |
2226 | } | |
2227 | ||
1da177e4 LT |
2228 | for (;;) { |
2229 | struct k_sigaction *ka; | |
1be53963 | 2230 | |
dd1d6772 TH |
2231 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2232 | do_signal_stop(0)) | |
7bcf6a2c | 2233 | goto relock; |
1be53963 | 2234 | |
73ddff2b TH |
2235 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2236 | do_jobctl_trap(); | |
2237 | spin_unlock_irq(&sighand->siglock); | |
2238 | goto relock; | |
2239 | } | |
1da177e4 | 2240 | |
828b1f65 | 2241 | signr = dequeue_signal(current, ¤t->blocked, &ksig->info); |
7bcf6a2c | 2242 | |
dd1d6772 TH |
2243 | if (!signr) |
2244 | break; /* will return 0 */ | |
7bcf6a2c | 2245 | |
8a352418 | 2246 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
828b1f65 | 2247 | signr = ptrace_signal(signr, &ksig->info); |
dd1d6772 TH |
2248 | if (!signr) |
2249 | continue; | |
1da177e4 LT |
2250 | } |
2251 | ||
dd1d6772 TH |
2252 | ka = &sighand->action[signr-1]; |
2253 | ||
f9d4257e | 2254 | /* Trace actually delivered signals. */ |
828b1f65 | 2255 | trace_signal_deliver(signr, &ksig->info, ka); |
f9d4257e | 2256 | |
1da177e4 LT |
2257 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2258 | continue; | |
2259 | if (ka->sa.sa_handler != SIG_DFL) { | |
2260 | /* Run the handler. */ | |
828b1f65 | 2261 | ksig->ka = *ka; |
1da177e4 LT |
2262 | |
2263 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2264 | ka->sa.sa_handler = SIG_DFL; | |
2265 | ||
2266 | break; /* will return non-zero "signr" value */ | |
2267 | } | |
2268 | ||
2269 | /* | |
2270 | * Now we are doing the default action for this signal. | |
2271 | */ | |
2272 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2273 | continue; | |
2274 | ||
84d73786 | 2275 | /* |
0fbc26a6 | 2276 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2277 | * Container-init gets no signals it doesn't want from same |
2278 | * container. | |
2279 | * | |
2280 | * Note that if global/container-init sees a sig_kernel_only() | |
2281 | * signal here, the signal must have been generated internally | |
2282 | * or must have come from an ancestor namespace. In either | |
2283 | * case, the signal cannot be dropped. | |
84d73786 | 2284 | */ |
fae5fa44 | 2285 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2286 | !sig_kernel_only(signr)) |
1da177e4 LT |
2287 | continue; |
2288 | ||
2289 | if (sig_kernel_stop(signr)) { | |
2290 | /* | |
2291 | * The default action is to stop all threads in | |
2292 | * the thread group. The job control signals | |
2293 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2294 | * always works. Note that siglock needs to be | |
2295 | * dropped during the call to is_orphaned_pgrp() | |
2296 | * because of lock ordering with tasklist_lock. | |
2297 | * This allows an intervening SIGCONT to be posted. | |
2298 | * We need to check for that and bail out if necessary. | |
2299 | */ | |
2300 | if (signr != SIGSTOP) { | |
f6b76d4f | 2301 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2302 | |
2303 | /* signals can be posted during this window */ | |
2304 | ||
3e7cd6c4 | 2305 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2306 | goto relock; |
2307 | ||
f6b76d4f | 2308 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2309 | } |
2310 | ||
828b1f65 | 2311 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
1da177e4 LT |
2312 | /* It released the siglock. */ |
2313 | goto relock; | |
2314 | } | |
2315 | ||
2316 | /* | |
2317 | * We didn't actually stop, due to a race | |
2318 | * with SIGCONT or something like that. | |
2319 | */ | |
2320 | continue; | |
2321 | } | |
2322 | ||
f6b76d4f | 2323 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2324 | |
2325 | /* | |
2326 | * Anything else is fatal, maybe with a core dump. | |
2327 | */ | |
2328 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2329 | |
1da177e4 | 2330 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2331 | if (print_fatal_signals) |
828b1f65 | 2332 | print_fatal_signal(ksig->info.si_signo); |
2b5faa4c | 2333 | proc_coredump_connector(current); |
1da177e4 LT |
2334 | /* |
2335 | * If it was able to dump core, this kills all | |
2336 | * other threads in the group and synchronizes with | |
2337 | * their demise. If we lost the race with another | |
2338 | * thread getting here, it set group_exit_code | |
2339 | * first and our do_group_exit call below will use | |
2340 | * that value and ignore the one we pass it. | |
2341 | */ | |
828b1f65 | 2342 | do_coredump(&ksig->info); |
1da177e4 LT |
2343 | } |
2344 | ||
2345 | /* | |
2346 | * Death signals, no core dump. | |
2347 | */ | |
828b1f65 | 2348 | do_group_exit(ksig->info.si_signo); |
1da177e4 LT |
2349 | /* NOTREACHED */ |
2350 | } | |
f6b76d4f | 2351 | spin_unlock_irq(&sighand->siglock); |
828b1f65 RW |
2352 | |
2353 | ksig->sig = signr; | |
2354 | return ksig->sig > 0; | |
1da177e4 LT |
2355 | } |
2356 | ||
5e6292c0 | 2357 | /** |
efee984c | 2358 | * signal_delivered - |
10b1c7ac | 2359 | * @ksig: kernel signal struct |
efee984c | 2360 | * @stepping: nonzero if debugger single-step or block-step in use |
5e6292c0 | 2361 | * |
e227867f | 2362 | * This function should be called when a signal has successfully been |
10b1c7ac | 2363 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
efee984c | 2364 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER |
10b1c7ac | 2365 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
5e6292c0 | 2366 | */ |
10b1c7ac | 2367 | static void signal_delivered(struct ksignal *ksig, int stepping) |
5e6292c0 MF |
2368 | { |
2369 | sigset_t blocked; | |
2370 | ||
a610d6e6 AV |
2371 | /* A signal was successfully delivered, and the |
2372 | saved sigmask was stored on the signal frame, | |
2373 | and will be restored by sigreturn. So we can | |
2374 | simply clear the restore sigmask flag. */ | |
2375 | clear_restore_sigmask(); | |
2376 | ||
10b1c7ac RW |
2377 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
2378 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) | |
2379 | sigaddset(&blocked, ksig->sig); | |
5e6292c0 | 2380 | set_current_blocked(&blocked); |
df5601f9 | 2381 | tracehook_signal_handler(stepping); |
5e6292c0 MF |
2382 | } |
2383 | ||
2ce5da17 AV |
2384 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2385 | { | |
2386 | if (failed) | |
2387 | force_sigsegv(ksig->sig, current); | |
2388 | else | |
10b1c7ac | 2389 | signal_delivered(ksig, stepping); |
2ce5da17 AV |
2390 | } |
2391 | ||
0edceb7b ON |
2392 | /* |
2393 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2394 | * group-wide signal. Other threads should be notified now to take |
2395 | * the shared signals in @which since we will not. | |
0edceb7b | 2396 | */ |
f646e227 | 2397 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2398 | { |
f646e227 | 2399 | sigset_t retarget; |
0edceb7b ON |
2400 | struct task_struct *t; |
2401 | ||
f646e227 ON |
2402 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2403 | if (sigisemptyset(&retarget)) | |
2404 | return; | |
2405 | ||
0edceb7b ON |
2406 | t = tsk; |
2407 | while_each_thread(tsk, t) { | |
fec9993d ON |
2408 | if (t->flags & PF_EXITING) |
2409 | continue; | |
2410 | ||
2411 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2412 | continue; | |
2413 | /* Remove the signals this thread can handle. */ | |
2414 | sigandsets(&retarget, &retarget, &t->blocked); | |
2415 | ||
2416 | if (!signal_pending(t)) | |
2417 | signal_wake_up(t, 0); | |
2418 | ||
2419 | if (sigisemptyset(&retarget)) | |
2420 | break; | |
0edceb7b ON |
2421 | } |
2422 | } | |
2423 | ||
d12619b5 ON |
2424 | void exit_signals(struct task_struct *tsk) |
2425 | { | |
2426 | int group_stop = 0; | |
f646e227 | 2427 | sigset_t unblocked; |
d12619b5 | 2428 | |
77e4ef99 TH |
2429 | /* |
2430 | * @tsk is about to have PF_EXITING set - lock out users which | |
2431 | * expect stable threadgroup. | |
2432 | */ | |
780de9dd | 2433 | cgroup_threadgroup_change_begin(tsk); |
77e4ef99 | 2434 | |
5dee1707 ON |
2435 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2436 | tsk->flags |= PF_EXITING; | |
780de9dd | 2437 | cgroup_threadgroup_change_end(tsk); |
5dee1707 | 2438 | return; |
d12619b5 ON |
2439 | } |
2440 | ||
5dee1707 | 2441 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2442 | /* |
2443 | * From now this task is not visible for group-wide signals, | |
2444 | * see wants_signal(), do_signal_stop(). | |
2445 | */ | |
2446 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2447 | |
780de9dd | 2448 | cgroup_threadgroup_change_end(tsk); |
77e4ef99 | 2449 | |
5dee1707 ON |
2450 | if (!signal_pending(tsk)) |
2451 | goto out; | |
2452 | ||
f646e227 ON |
2453 | unblocked = tsk->blocked; |
2454 | signotset(&unblocked); | |
2455 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2456 | |
a8f072c1 | 2457 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2458 | task_participate_group_stop(tsk)) |
edf2ed15 | 2459 | group_stop = CLD_STOPPED; |
5dee1707 | 2460 | out: |
d12619b5 ON |
2461 | spin_unlock_irq(&tsk->sighand->siglock); |
2462 | ||
62bcf9d9 TH |
2463 | /* |
2464 | * If group stop has completed, deliver the notification. This | |
2465 | * should always go to the real parent of the group leader. | |
2466 | */ | |
ae6d2ed7 | 2467 | if (unlikely(group_stop)) { |
d12619b5 | 2468 | read_lock(&tasklist_lock); |
62bcf9d9 | 2469 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2470 | read_unlock(&tasklist_lock); |
2471 | } | |
2472 | } | |
2473 | ||
1da177e4 LT |
2474 | EXPORT_SYMBOL(recalc_sigpending); |
2475 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2476 | EXPORT_SYMBOL(flush_signals); | |
2477 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2478 | EXPORT_SYMBOL(send_sig); |
2479 | EXPORT_SYMBOL(send_sig_info); | |
2480 | EXPORT_SYMBOL(sigprocmask); | |
1da177e4 LT |
2481 | |
2482 | /* | |
2483 | * System call entry points. | |
2484 | */ | |
2485 | ||
41c57892 RD |
2486 | /** |
2487 | * sys_restart_syscall - restart a system call | |
2488 | */ | |
754fe8d2 | 2489 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 | 2490 | { |
f56141e3 | 2491 | struct restart_block *restart = ¤t->restart_block; |
1da177e4 LT |
2492 | return restart->fn(restart); |
2493 | } | |
2494 | ||
2495 | long do_no_restart_syscall(struct restart_block *param) | |
2496 | { | |
2497 | return -EINTR; | |
2498 | } | |
2499 | ||
b182801a ON |
2500 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2501 | { | |
2502 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2503 | sigset_t newblocked; | |
2504 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2505 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2506 | retarget_shared_pending(tsk, &newblocked); |
2507 | } | |
2508 | tsk->blocked = *newset; | |
2509 | recalc_sigpending(); | |
2510 | } | |
2511 | ||
e6fa16ab ON |
2512 | /** |
2513 | * set_current_blocked - change current->blocked mask | |
2514 | * @newset: new mask | |
2515 | * | |
2516 | * It is wrong to change ->blocked directly, this helper should be used | |
2517 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2518 | */ |
77097ae5 AV |
2519 | void set_current_blocked(sigset_t *newset) |
2520 | { | |
77097ae5 | 2521 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2522 | __set_current_blocked(newset); |
77097ae5 AV |
2523 | } |
2524 | ||
2525 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2526 | { |
2527 | struct task_struct *tsk = current; | |
2528 | ||
c7be96af WL |
2529 | /* |
2530 | * In case the signal mask hasn't changed, there is nothing we need | |
2531 | * to do. The current->blocked shouldn't be modified by other task. | |
2532 | */ | |
2533 | if (sigequalsets(&tsk->blocked, newset)) | |
2534 | return; | |
2535 | ||
e6fa16ab | 2536 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2537 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2538 | spin_unlock_irq(&tsk->sighand->siglock); |
2539 | } | |
1da177e4 LT |
2540 | |
2541 | /* | |
2542 | * This is also useful for kernel threads that want to temporarily | |
2543 | * (or permanently) block certain signals. | |
2544 | * | |
2545 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2546 | * interface happily blocks "unblockable" signals like SIGKILL | |
2547 | * and friends. | |
2548 | */ | |
2549 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2550 | { | |
73ef4aeb ON |
2551 | struct task_struct *tsk = current; |
2552 | sigset_t newset; | |
1da177e4 | 2553 | |
73ef4aeb | 2554 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2555 | if (oldset) |
73ef4aeb | 2556 | *oldset = tsk->blocked; |
a26fd335 | 2557 | |
1da177e4 LT |
2558 | switch (how) { |
2559 | case SIG_BLOCK: | |
73ef4aeb | 2560 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2561 | break; |
2562 | case SIG_UNBLOCK: | |
702a5073 | 2563 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2564 | break; |
2565 | case SIG_SETMASK: | |
73ef4aeb | 2566 | newset = *set; |
1da177e4 LT |
2567 | break; |
2568 | default: | |
73ef4aeb | 2569 | return -EINVAL; |
1da177e4 | 2570 | } |
a26fd335 | 2571 | |
77097ae5 | 2572 | __set_current_blocked(&newset); |
73ef4aeb | 2573 | return 0; |
1da177e4 LT |
2574 | } |
2575 | ||
41c57892 RD |
2576 | /** |
2577 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2578 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2579 | * @nset: stores pending signals |
41c57892 RD |
2580 | * @oset: previous value of signal mask if non-null |
2581 | * @sigsetsize: size of sigset_t type | |
2582 | */ | |
bb7efee2 | 2583 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2584 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2585 | { |
1da177e4 | 2586 | sigset_t old_set, new_set; |
bb7efee2 | 2587 | int error; |
1da177e4 LT |
2588 | |
2589 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2590 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2591 | return -EINVAL; |
1da177e4 | 2592 | |
bb7efee2 ON |
2593 | old_set = current->blocked; |
2594 | ||
2595 | if (nset) { | |
2596 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2597 | return -EFAULT; | |
1da177e4 LT |
2598 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2599 | ||
bb7efee2 | 2600 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2601 | if (error) |
bb7efee2 ON |
2602 | return error; |
2603 | } | |
1da177e4 | 2604 | |
bb7efee2 ON |
2605 | if (oset) { |
2606 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2607 | return -EFAULT; | |
1da177e4 | 2608 | } |
bb7efee2 ON |
2609 | |
2610 | return 0; | |
1da177e4 LT |
2611 | } |
2612 | ||
322a56cb | 2613 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2614 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2615 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2616 | { |
322a56cb AV |
2617 | sigset_t old_set = current->blocked; |
2618 | ||
2619 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2620 | if (sigsetsize != sizeof(sigset_t)) | |
2621 | return -EINVAL; | |
2622 | ||
2623 | if (nset) { | |
322a56cb AV |
2624 | sigset_t new_set; |
2625 | int error; | |
3968cf62 | 2626 | if (get_compat_sigset(&new_set, nset)) |
322a56cb | 2627 | return -EFAULT; |
322a56cb AV |
2628 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2629 | ||
2630 | error = sigprocmask(how, &new_set, NULL); | |
2631 | if (error) | |
2632 | return error; | |
2633 | } | |
f454322e | 2634 | return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; |
322a56cb AV |
2635 | } |
2636 | #endif | |
1da177e4 | 2637 | |
176826af | 2638 | static int do_sigpending(sigset_t *set) |
1da177e4 | 2639 | { |
1da177e4 | 2640 | spin_lock_irq(¤t->sighand->siglock); |
fe9c1db2 | 2641 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
2642 | ¤t->signal->shared_pending.signal); |
2643 | spin_unlock_irq(¤t->sighand->siglock); | |
2644 | ||
2645 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 AV |
2646 | sigandsets(set, ¤t->blocked, set); |
2647 | return 0; | |
5aba085e | 2648 | } |
1da177e4 | 2649 | |
41c57892 RD |
2650 | /** |
2651 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2652 | * while blocked | |
20f22ab4 | 2653 | * @uset: stores pending signals |
41c57892 RD |
2654 | * @sigsetsize: size of sigset_t type or larger |
2655 | */ | |
fe9c1db2 | 2656 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 2657 | { |
fe9c1db2 | 2658 | sigset_t set; |
176826af DL |
2659 | int err; |
2660 | ||
2661 | if (sigsetsize > sizeof(*uset)) | |
2662 | return -EINVAL; | |
2663 | ||
2664 | err = do_sigpending(&set); | |
fe9c1db2 AV |
2665 | if (!err && copy_to_user(uset, &set, sigsetsize)) |
2666 | err = -EFAULT; | |
2667 | return err; | |
2668 | } | |
2669 | ||
2670 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
2671 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
2672 | compat_size_t, sigsetsize) | |
1da177e4 | 2673 | { |
fe9c1db2 | 2674 | sigset_t set; |
176826af DL |
2675 | int err; |
2676 | ||
2677 | if (sigsetsize > sizeof(*uset)) | |
2678 | return -EINVAL; | |
2679 | ||
2680 | err = do_sigpending(&set); | |
f454322e DL |
2681 | if (!err) |
2682 | err = put_compat_sigset(uset, &set, sigsetsize); | |
fe9c1db2 | 2683 | return err; |
1da177e4 | 2684 | } |
fe9c1db2 | 2685 | #endif |
1da177e4 | 2686 | |
9cbc4a39 | 2687 | enum siginfo_layout siginfo_layout(unsigned sig, int si_code) |
cc731525 EB |
2688 | { |
2689 | enum siginfo_layout layout = SIL_KILL; | |
2690 | if ((si_code > SI_USER) && (si_code < SI_KERNEL)) { | |
2691 | static const struct { | |
2692 | unsigned char limit, layout; | |
2693 | } filter[] = { | |
2694 | [SIGILL] = { NSIGILL, SIL_FAULT }, | |
2695 | [SIGFPE] = { NSIGFPE, SIL_FAULT }, | |
2696 | [SIGSEGV] = { NSIGSEGV, SIL_FAULT }, | |
2697 | [SIGBUS] = { NSIGBUS, SIL_FAULT }, | |
2698 | [SIGTRAP] = { NSIGTRAP, SIL_FAULT }, | |
c3aff086 | 2699 | #if defined(SIGEMT) && defined(NSIGEMT) |
cc731525 EB |
2700 | [SIGEMT] = { NSIGEMT, SIL_FAULT }, |
2701 | #endif | |
2702 | [SIGCHLD] = { NSIGCHLD, SIL_CHLD }, | |
2703 | [SIGPOLL] = { NSIGPOLL, SIL_POLL }, | |
2704 | #ifdef __ARCH_SIGSYS | |
2705 | [SIGSYS] = { NSIGSYS, SIL_SYS }, | |
2706 | #endif | |
2707 | }; | |
2708 | if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) | |
2709 | layout = filter[sig].layout; | |
2710 | else if (si_code <= NSIGPOLL) | |
2711 | layout = SIL_POLL; | |
2712 | } else { | |
2713 | if (si_code == SI_TIMER) | |
2714 | layout = SIL_TIMER; | |
2715 | else if (si_code == SI_SIGIO) | |
2716 | layout = SIL_POLL; | |
2717 | else if (si_code < 0) | |
2718 | layout = SIL_RT; | |
2719 | /* Tests to support buggy kernel ABIs */ | |
2720 | #ifdef TRAP_FIXME | |
2721 | if ((sig == SIGTRAP) && (si_code == TRAP_FIXME)) | |
2722 | layout = SIL_FAULT; | |
2723 | #endif | |
2724 | #ifdef FPE_FIXME | |
2725 | if ((sig == SIGFPE) && (si_code == FPE_FIXME)) | |
2726 | layout = SIL_FAULT; | |
2727 | #endif | |
2728 | } | |
2729 | return layout; | |
2730 | } | |
2731 | ||
1da177e4 LT |
2732 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER |
2733 | ||
ce395960 | 2734 | int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) |
1da177e4 LT |
2735 | { |
2736 | int err; | |
2737 | ||
2738 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2739 | return -EFAULT; | |
2740 | if (from->si_code < 0) | |
2741 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2742 | ? -EFAULT : 0; | |
2743 | /* | |
2744 | * If you change siginfo_t structure, please be sure | |
2745 | * this code is fixed accordingly. | |
fba2afaa DL |
2746 | * Please remember to update the signalfd_copyinfo() function |
2747 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2748 | * It should never copy any pad contained in the structure |
2749 | * to avoid security leaks, but must copy the generic | |
2750 | * 3 ints plus the relevant union member. | |
2751 | */ | |
2752 | err = __put_user(from->si_signo, &to->si_signo); | |
2753 | err |= __put_user(from->si_errno, &to->si_errno); | |
cc731525 EB |
2754 | err |= __put_user(from->si_code, &to->si_code); |
2755 | switch (siginfo_layout(from->si_signo, from->si_code)) { | |
2756 | case SIL_KILL: | |
1da177e4 LT |
2757 | err |= __put_user(from->si_pid, &to->si_pid); |
2758 | err |= __put_user(from->si_uid, &to->si_uid); | |
2759 | break; | |
cc731525 EB |
2760 | case SIL_TIMER: |
2761 | /* Unreached SI_TIMER is negative */ | |
1da177e4 | 2762 | break; |
cc731525 | 2763 | case SIL_POLL: |
1da177e4 LT |
2764 | err |= __put_user(from->si_band, &to->si_band); |
2765 | err |= __put_user(from->si_fd, &to->si_fd); | |
2766 | break; | |
cc731525 | 2767 | case SIL_FAULT: |
1da177e4 LT |
2768 | err |= __put_user(from->si_addr, &to->si_addr); |
2769 | #ifdef __ARCH_SI_TRAPNO | |
2770 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2771 | #endif |
2772 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2773 | /* |
a337fdac | 2774 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2775 | * so check explicitly for the right codes here. |
a337fdac | 2776 | */ |
26135022 AA |
2777 | if (from->si_signo == SIGBUS && |
2778 | (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) | |
a337fdac | 2779 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); |
ee1b58d3 QR |
2780 | #endif |
2781 | #ifdef SEGV_BNDERR | |
26135022 AA |
2782 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) { |
2783 | err |= __put_user(from->si_lower, &to->si_lower); | |
2784 | err |= __put_user(from->si_upper, &to->si_upper); | |
2785 | } | |
cd0ea35f DH |
2786 | #endif |
2787 | #ifdef SEGV_PKUERR | |
2788 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR) | |
2789 | err |= __put_user(from->si_pkey, &to->si_pkey); | |
1da177e4 LT |
2790 | #endif |
2791 | break; | |
cc731525 | 2792 | case SIL_CHLD: |
1da177e4 LT |
2793 | err |= __put_user(from->si_pid, &to->si_pid); |
2794 | err |= __put_user(from->si_uid, &to->si_uid); | |
2795 | err |= __put_user(from->si_status, &to->si_status); | |
2796 | err |= __put_user(from->si_utime, &to->si_utime); | |
2797 | err |= __put_user(from->si_stime, &to->si_stime); | |
2798 | break; | |
cc731525 | 2799 | case SIL_RT: |
1da177e4 LT |
2800 | err |= __put_user(from->si_pid, &to->si_pid); |
2801 | err |= __put_user(from->si_uid, &to->si_uid); | |
2802 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2803 | break; | |
a0727e8c | 2804 | #ifdef __ARCH_SIGSYS |
cc731525 | 2805 | case SIL_SYS: |
a0727e8c WD |
2806 | err |= __put_user(from->si_call_addr, &to->si_call_addr); |
2807 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2808 | err |= __put_user(from->si_arch, &to->si_arch); | |
2809 | break; | |
2810 | #endif | |
1da177e4 LT |
2811 | } |
2812 | return err; | |
2813 | } | |
2814 | ||
2815 | #endif | |
2816 | ||
943df148 ON |
2817 | /** |
2818 | * do_sigtimedwait - wait for queued signals specified in @which | |
2819 | * @which: queued signals to wait for | |
2820 | * @info: if non-null, the signal's siginfo is returned here | |
2821 | * @ts: upper bound on process time suspension | |
2822 | */ | |
1b3c872c | 2823 | static int do_sigtimedwait(const sigset_t *which, siginfo_t *info, |
2b1ecc3d | 2824 | const struct timespec *ts) |
943df148 | 2825 | { |
2456e855 | 2826 | ktime_t *to = NULL, timeout = KTIME_MAX; |
943df148 | 2827 | struct task_struct *tsk = current; |
943df148 | 2828 | sigset_t mask = *which; |
2b1ecc3d | 2829 | int sig, ret = 0; |
943df148 ON |
2830 | |
2831 | if (ts) { | |
2832 | if (!timespec_valid(ts)) | |
2833 | return -EINVAL; | |
2b1ecc3d TG |
2834 | timeout = timespec_to_ktime(*ts); |
2835 | to = &timeout; | |
943df148 ON |
2836 | } |
2837 | ||
2838 | /* | |
2839 | * Invert the set of allowed signals to get those we want to block. | |
2840 | */ | |
2841 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2842 | signotset(&mask); | |
2843 | ||
2844 | spin_lock_irq(&tsk->sighand->siglock); | |
2845 | sig = dequeue_signal(tsk, &mask, info); | |
2456e855 | 2846 | if (!sig && timeout) { |
943df148 ON |
2847 | /* |
2848 | * None ready, temporarily unblock those we're interested | |
2849 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2850 | * they arrive. Unblocking is always fine, we can avoid |
2851 | * set_current_blocked(). | |
943df148 ON |
2852 | */ |
2853 | tsk->real_blocked = tsk->blocked; | |
2854 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2855 | recalc_sigpending(); | |
2856 | spin_unlock_irq(&tsk->sighand->siglock); | |
2857 | ||
2b1ecc3d TG |
2858 | __set_current_state(TASK_INTERRUPTIBLE); |
2859 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, | |
2860 | HRTIMER_MODE_REL); | |
943df148 | 2861 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2862 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 2863 | sigemptyset(&tsk->real_blocked); |
b182801a | 2864 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2865 | } |
2866 | spin_unlock_irq(&tsk->sighand->siglock); | |
2867 | ||
2868 | if (sig) | |
2869 | return sig; | |
2b1ecc3d | 2870 | return ret ? -EINTR : -EAGAIN; |
943df148 ON |
2871 | } |
2872 | ||
41c57892 RD |
2873 | /** |
2874 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2875 | * in @uthese | |
2876 | * @uthese: queued signals to wait for | |
2877 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2878 | * @uts: upper bound on process time suspension | |
2879 | * @sigsetsize: size of sigset_t type | |
2880 | */ | |
17da2bd9 HC |
2881 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2882 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2883 | size_t, sigsetsize) | |
1da177e4 | 2884 | { |
1da177e4 LT |
2885 | sigset_t these; |
2886 | struct timespec ts; | |
2887 | siginfo_t info; | |
943df148 | 2888 | int ret; |
1da177e4 LT |
2889 | |
2890 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2891 | if (sigsetsize != sizeof(sigset_t)) | |
2892 | return -EINVAL; | |
2893 | ||
2894 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2895 | return -EFAULT; | |
5aba085e | 2896 | |
1da177e4 LT |
2897 | if (uts) { |
2898 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2899 | return -EFAULT; | |
1da177e4 LT |
2900 | } |
2901 | ||
943df148 | 2902 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2903 | |
943df148 ON |
2904 | if (ret > 0 && uinfo) { |
2905 | if (copy_siginfo_to_user(uinfo, &info)) | |
2906 | ret = -EFAULT; | |
1da177e4 LT |
2907 | } |
2908 | ||
2909 | return ret; | |
2910 | } | |
2911 | ||
1b3c872c AV |
2912 | #ifdef CONFIG_COMPAT |
2913 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese, | |
2914 | struct compat_siginfo __user *, uinfo, | |
2915 | struct compat_timespec __user *, uts, compat_size_t, sigsetsize) | |
2916 | { | |
1b3c872c AV |
2917 | sigset_t s; |
2918 | struct timespec t; | |
2919 | siginfo_t info; | |
2920 | long ret; | |
2921 | ||
2922 | if (sigsetsize != sizeof(sigset_t)) | |
2923 | return -EINVAL; | |
2924 | ||
3968cf62 | 2925 | if (get_compat_sigset(&s, uthese)) |
1b3c872c | 2926 | return -EFAULT; |
1b3c872c AV |
2927 | |
2928 | if (uts) { | |
2929 | if (compat_get_timespec(&t, uts)) | |
2930 | return -EFAULT; | |
2931 | } | |
2932 | ||
2933 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); | |
2934 | ||
2935 | if (ret > 0 && uinfo) { | |
2936 | if (copy_siginfo_to_user32(uinfo, &info)) | |
2937 | ret = -EFAULT; | |
2938 | } | |
2939 | ||
2940 | return ret; | |
2941 | } | |
2942 | #endif | |
2943 | ||
41c57892 RD |
2944 | /** |
2945 | * sys_kill - send a signal to a process | |
2946 | * @pid: the PID of the process | |
2947 | * @sig: signal to be sent | |
2948 | */ | |
17da2bd9 | 2949 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
2950 | { |
2951 | struct siginfo info; | |
2952 | ||
2953 | info.si_signo = sig; | |
2954 | info.si_errno = 0; | |
2955 | info.si_code = SI_USER; | |
b488893a | 2956 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 2957 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2958 | |
2959 | return kill_something_info(sig, &info, pid); | |
2960 | } | |
2961 | ||
30b4ae8a TG |
2962 | static int |
2963 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 2964 | { |
1da177e4 | 2965 | struct task_struct *p; |
30b4ae8a | 2966 | int error = -ESRCH; |
1da177e4 | 2967 | |
3547ff3a | 2968 | rcu_read_lock(); |
228ebcbe | 2969 | p = find_task_by_vpid(pid); |
b488893a | 2970 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 2971 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
2972 | /* |
2973 | * The null signal is a permissions and process existence | |
2974 | * probe. No signal is actually delivered. | |
2975 | */ | |
4a30debf ON |
2976 | if (!error && sig) { |
2977 | error = do_send_sig_info(sig, info, p, false); | |
2978 | /* | |
2979 | * If lock_task_sighand() failed we pretend the task | |
2980 | * dies after receiving the signal. The window is tiny, | |
2981 | * and the signal is private anyway. | |
2982 | */ | |
2983 | if (unlikely(error == -ESRCH)) | |
2984 | error = 0; | |
1da177e4 LT |
2985 | } |
2986 | } | |
3547ff3a | 2987 | rcu_read_unlock(); |
6dd69f10 | 2988 | |
1da177e4 LT |
2989 | return error; |
2990 | } | |
2991 | ||
30b4ae8a TG |
2992 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
2993 | { | |
b9e146d8 | 2994 | struct siginfo info = {}; |
30b4ae8a TG |
2995 | |
2996 | info.si_signo = sig; | |
2997 | info.si_errno = 0; | |
2998 | info.si_code = SI_TKILL; | |
2999 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 3000 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
3001 | |
3002 | return do_send_specific(tgid, pid, sig, &info); | |
3003 | } | |
3004 | ||
6dd69f10 VL |
3005 | /** |
3006 | * sys_tgkill - send signal to one specific thread | |
3007 | * @tgid: the thread group ID of the thread | |
3008 | * @pid: the PID of the thread | |
3009 | * @sig: signal to be sent | |
3010 | * | |
72fd4a35 | 3011 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
3012 | * exists but it's not belonging to the target process anymore. This |
3013 | * method solves the problem of threads exiting and PIDs getting reused. | |
3014 | */ | |
a5f8fa9e | 3015 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
3016 | { |
3017 | /* This is only valid for single tasks */ | |
3018 | if (pid <= 0 || tgid <= 0) | |
3019 | return -EINVAL; | |
3020 | ||
3021 | return do_tkill(tgid, pid, sig); | |
3022 | } | |
3023 | ||
41c57892 RD |
3024 | /** |
3025 | * sys_tkill - send signal to one specific task | |
3026 | * @pid: the PID of the task | |
3027 | * @sig: signal to be sent | |
3028 | * | |
1da177e4 LT |
3029 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
3030 | */ | |
a5f8fa9e | 3031 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 3032 | { |
1da177e4 LT |
3033 | /* This is only valid for single tasks */ |
3034 | if (pid <= 0) | |
3035 | return -EINVAL; | |
3036 | ||
6dd69f10 | 3037 | return do_tkill(0, pid, sig); |
1da177e4 LT |
3038 | } |
3039 | ||
75907d4d AV |
3040 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) |
3041 | { | |
3042 | /* Not even root can pretend to send signals from the kernel. | |
3043 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
3044 | */ | |
66dd34ad | 3045 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
69828dce | 3046 | (task_pid_vnr(current) != pid)) |
75907d4d | 3047 | return -EPERM; |
69828dce | 3048 | |
75907d4d AV |
3049 | info->si_signo = sig; |
3050 | ||
3051 | /* POSIX.1b doesn't mention process groups. */ | |
3052 | return kill_proc_info(sig, info, pid); | |
3053 | } | |
3054 | ||
41c57892 RD |
3055 | /** |
3056 | * sys_rt_sigqueueinfo - send signal information to a signal | |
3057 | * @pid: the PID of the thread | |
3058 | * @sig: signal to be sent | |
3059 | * @uinfo: signal info to be sent | |
3060 | */ | |
a5f8fa9e HC |
3061 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
3062 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
3063 | { |
3064 | siginfo_t info; | |
1da177e4 LT |
3065 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) |
3066 | return -EFAULT; | |
75907d4d AV |
3067 | return do_rt_sigqueueinfo(pid, sig, &info); |
3068 | } | |
1da177e4 | 3069 | |
75907d4d | 3070 | #ifdef CONFIG_COMPAT |
75907d4d AV |
3071 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
3072 | compat_pid_t, pid, | |
3073 | int, sig, | |
3074 | struct compat_siginfo __user *, uinfo) | |
3075 | { | |
3c00cb5e | 3076 | siginfo_t info = {}; |
75907d4d AV |
3077 | int ret = copy_siginfo_from_user32(&info, uinfo); |
3078 | if (unlikely(ret)) | |
3079 | return ret; | |
3080 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 3081 | } |
75907d4d | 3082 | #endif |
1da177e4 | 3083 | |
9aae8fc0 | 3084 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
62ab4505 TG |
3085 | { |
3086 | /* This is only valid for single tasks */ | |
3087 | if (pid <= 0 || tgid <= 0) | |
3088 | return -EINVAL; | |
3089 | ||
3090 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3091 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3092 | */ | |
69828dce VD |
3093 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3094 | (task_pid_vnr(current) != pid)) | |
62ab4505 | 3095 | return -EPERM; |
69828dce | 3096 | |
62ab4505 TG |
3097 | info->si_signo = sig; |
3098 | ||
3099 | return do_send_specific(tgid, pid, sig, info); | |
3100 | } | |
3101 | ||
3102 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3103 | siginfo_t __user *, uinfo) | |
3104 | { | |
3105 | siginfo_t info; | |
3106 | ||
3107 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3108 | return -EFAULT; | |
3109 | ||
3110 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3111 | } | |
3112 | ||
9aae8fc0 AV |
3113 | #ifdef CONFIG_COMPAT |
3114 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3115 | compat_pid_t, tgid, | |
3116 | compat_pid_t, pid, | |
3117 | int, sig, | |
3118 | struct compat_siginfo __user *, uinfo) | |
3119 | { | |
3c00cb5e | 3120 | siginfo_t info = {}; |
9aae8fc0 AV |
3121 | |
3122 | if (copy_siginfo_from_user32(&info, uinfo)) | |
3123 | return -EFAULT; | |
3124 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3125 | } | |
3126 | #endif | |
3127 | ||
0341729b | 3128 | /* |
b4e74264 | 3129 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
0341729b | 3130 | */ |
b4e74264 | 3131 | void kernel_sigaction(int sig, __sighandler_t action) |
0341729b | 3132 | { |
ec5955b8 | 3133 | spin_lock_irq(¤t->sighand->siglock); |
b4e74264 ON |
3134 | current->sighand->action[sig - 1].sa.sa_handler = action; |
3135 | if (action == SIG_IGN) { | |
3136 | sigset_t mask; | |
0341729b | 3137 | |
b4e74264 ON |
3138 | sigemptyset(&mask); |
3139 | sigaddset(&mask, sig); | |
580d34e4 | 3140 | |
b4e74264 ON |
3141 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
3142 | flush_sigqueue_mask(&mask, ¤t->pending); | |
3143 | recalc_sigpending(); | |
3144 | } | |
0341729b ON |
3145 | spin_unlock_irq(¤t->sighand->siglock); |
3146 | } | |
b4e74264 | 3147 | EXPORT_SYMBOL(kernel_sigaction); |
0341729b | 3148 | |
68463510 DS |
3149 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
3150 | struct k_sigaction *oact) | |
3151 | { | |
3152 | } | |
3153 | ||
88531f72 | 3154 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3155 | { |
afe2b038 | 3156 | struct task_struct *p = current, *t; |
1da177e4 | 3157 | struct k_sigaction *k; |
71fabd5e | 3158 | sigset_t mask; |
1da177e4 | 3159 | |
7ed20e1a | 3160 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3161 | return -EINVAL; |
3162 | ||
afe2b038 | 3163 | k = &p->sighand->action[sig-1]; |
1da177e4 | 3164 | |
afe2b038 | 3165 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
3166 | if (oact) |
3167 | *oact = *k; | |
3168 | ||
68463510 DS |
3169 | sigaction_compat_abi(act, oact); |
3170 | ||
1da177e4 | 3171 | if (act) { |
9ac95f2f ON |
3172 | sigdelsetmask(&act->sa.sa_mask, |
3173 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3174 | *k = *act; |
1da177e4 LT |
3175 | /* |
3176 | * POSIX 3.3.1.3: | |
3177 | * "Setting a signal action to SIG_IGN for a signal that is | |
3178 | * pending shall cause the pending signal to be discarded, | |
3179 | * whether or not it is blocked." | |
3180 | * | |
3181 | * "Setting a signal action to SIG_DFL for a signal that is | |
3182 | * pending and whose default action is to ignore the signal | |
3183 | * (for example, SIGCHLD), shall cause the pending signal to | |
3184 | * be discarded, whether or not it is blocked" | |
3185 | */ | |
afe2b038 | 3186 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
71fabd5e GA |
3187 | sigemptyset(&mask); |
3188 | sigaddset(&mask, sig); | |
afe2b038 ON |
3189 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
3190 | for_each_thread(p, t) | |
c09c1441 | 3191 | flush_sigqueue_mask(&mask, &t->pending); |
1da177e4 | 3192 | } |
1da177e4 LT |
3193 | } |
3194 | ||
afe2b038 | 3195 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
3196 | return 0; |
3197 | } | |
3198 | ||
c09c1441 | 3199 | static int |
50ff5fd2 WD |
3200 | do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, |
3201 | size_t min_ss_size) | |
1da177e4 | 3202 | { |
bcfe8ad8 | 3203 | struct task_struct *t = current; |
1da177e4 | 3204 | |
bcfe8ad8 AV |
3205 | if (oss) { |
3206 | memset(oss, 0, sizeof(stack_t)); | |
3207 | oss->ss_sp = (void __user *) t->sas_ss_sp; | |
3208 | oss->ss_size = t->sas_ss_size; | |
3209 | oss->ss_flags = sas_ss_flags(sp) | | |
3210 | (current->sas_ss_flags & SS_FLAG_BITS); | |
3211 | } | |
1da177e4 | 3212 | |
bcfe8ad8 AV |
3213 | if (ss) { |
3214 | void __user *ss_sp = ss->ss_sp; | |
3215 | size_t ss_size = ss->ss_size; | |
3216 | unsigned ss_flags = ss->ss_flags; | |
407bc16a | 3217 | int ss_mode; |
1da177e4 | 3218 | |
bcfe8ad8 AV |
3219 | if (unlikely(on_sig_stack(sp))) |
3220 | return -EPERM; | |
1da177e4 | 3221 | |
407bc16a | 3222 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
bcfe8ad8 AV |
3223 | if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
3224 | ss_mode != 0)) | |
3225 | return -EINVAL; | |
1da177e4 | 3226 | |
407bc16a | 3227 | if (ss_mode == SS_DISABLE) { |
1da177e4 LT |
3228 | ss_size = 0; |
3229 | ss_sp = NULL; | |
3230 | } else { | |
50ff5fd2 | 3231 | if (unlikely(ss_size < min_ss_size)) |
bcfe8ad8 | 3232 | return -ENOMEM; |
1da177e4 LT |
3233 | } |
3234 | ||
bcfe8ad8 AV |
3235 | t->sas_ss_sp = (unsigned long) ss_sp; |
3236 | t->sas_ss_size = ss_size; | |
3237 | t->sas_ss_flags = ss_flags; | |
1da177e4 | 3238 | } |
bcfe8ad8 | 3239 | return 0; |
1da177e4 | 3240 | } |
bcfe8ad8 | 3241 | |
6bf9adfc AV |
3242 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3243 | { | |
bcfe8ad8 AV |
3244 | stack_t new, old; |
3245 | int err; | |
3246 | if (uss && copy_from_user(&new, uss, sizeof(stack_t))) | |
3247 | return -EFAULT; | |
3248 | err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL, | |
50ff5fd2 WD |
3249 | current_user_stack_pointer(), |
3250 | MINSIGSTKSZ); | |
bcfe8ad8 AV |
3251 | if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t))) |
3252 | err = -EFAULT; | |
3253 | return err; | |
6bf9adfc | 3254 | } |
1da177e4 | 3255 | |
5c49574f AV |
3256 | int restore_altstack(const stack_t __user *uss) |
3257 | { | |
bcfe8ad8 AV |
3258 | stack_t new; |
3259 | if (copy_from_user(&new, uss, sizeof(stack_t))) | |
3260 | return -EFAULT; | |
50ff5fd2 WD |
3261 | (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(), |
3262 | MINSIGSTKSZ); | |
5c49574f | 3263 | /* squash all but EFAULT for now */ |
bcfe8ad8 | 3264 | return 0; |
5c49574f AV |
3265 | } |
3266 | ||
c40702c4 AV |
3267 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3268 | { | |
3269 | struct task_struct *t = current; | |
2a742138 SS |
3270 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
3271 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3272 | __put_user(t->sas_ss_size, &uss->ss_size); |
2a742138 SS |
3273 | if (err) |
3274 | return err; | |
3275 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3276 | sas_ss_reset(t); | |
3277 | return 0; | |
c40702c4 AV |
3278 | } |
3279 | ||
90268439 | 3280 | #ifdef CONFIG_COMPAT |
90228fc1 AV |
3281 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
3282 | const compat_stack_t __user *, uss_ptr, | |
3283 | compat_stack_t __user *, uoss_ptr) | |
90268439 AV |
3284 | { |
3285 | stack_t uss, uoss; | |
3286 | int ret; | |
90268439 AV |
3287 | |
3288 | if (uss_ptr) { | |
3289 | compat_stack_t uss32; | |
90268439 AV |
3290 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) |
3291 | return -EFAULT; | |
3292 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
3293 | uss.ss_flags = uss32.ss_flags; | |
3294 | uss.ss_size = uss32.ss_size; | |
3295 | } | |
bcfe8ad8 | 3296 | ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, |
50ff5fd2 WD |
3297 | compat_user_stack_pointer(), |
3298 | COMPAT_MINSIGSTKSZ); | |
90268439 | 3299 | if (ret >= 0 && uoss_ptr) { |
bcfe8ad8 AV |
3300 | compat_stack_t old; |
3301 | memset(&old, 0, sizeof(old)); | |
3302 | old.ss_sp = ptr_to_compat(uoss.ss_sp); | |
3303 | old.ss_flags = uoss.ss_flags; | |
3304 | old.ss_size = uoss.ss_size; | |
3305 | if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t))) | |
90268439 AV |
3306 | ret = -EFAULT; |
3307 | } | |
3308 | return ret; | |
3309 | } | |
3310 | ||
3311 | int compat_restore_altstack(const compat_stack_t __user *uss) | |
3312 | { | |
3313 | int err = compat_sys_sigaltstack(uss, NULL); | |
3314 | /* squash all but -EFAULT for now */ | |
3315 | return err == -EFAULT ? err : 0; | |
3316 | } | |
c40702c4 AV |
3317 | |
3318 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
3319 | { | |
441398d3 | 3320 | int err; |
c40702c4 | 3321 | struct task_struct *t = current; |
441398d3 SS |
3322 | err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
3323 | &uss->ss_sp) | | |
3324 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3325 | __put_user(t->sas_ss_size, &uss->ss_size); |
441398d3 SS |
3326 | if (err) |
3327 | return err; | |
3328 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3329 | sas_ss_reset(t); | |
3330 | return 0; | |
c40702c4 | 3331 | } |
90268439 | 3332 | #endif |
1da177e4 LT |
3333 | |
3334 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3335 | ||
41c57892 RD |
3336 | /** |
3337 | * sys_sigpending - examine pending signals | |
3338 | * @set: where mask of pending signal is returned | |
3339 | */ | |
b290ebe2 | 3340 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 | 3341 | { |
fe9c1db2 | 3342 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); |
1da177e4 LT |
3343 | } |
3344 | ||
8f13621a AV |
3345 | #ifdef CONFIG_COMPAT |
3346 | COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) | |
3347 | { | |
3348 | sigset_t set; | |
176826af | 3349 | int err = do_sigpending(&set); |
fbb77611 DL |
3350 | if (!err) |
3351 | err = put_user(set.sig[0], set32); | |
8f13621a AV |
3352 | return err; |
3353 | } | |
3354 | #endif | |
3355 | ||
1da177e4 LT |
3356 | #endif |
3357 | ||
3358 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3359 | /** |
3360 | * sys_sigprocmask - examine and change blocked signals | |
3361 | * @how: whether to add, remove, or set signals | |
b013c399 | 3362 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3363 | * @oset: previous value of signal mask if non-null |
3364 | * | |
5aba085e RD |
3365 | * Some platforms have their own version with special arguments; |
3366 | * others support only sys_rt_sigprocmask. | |
3367 | */ | |
1da177e4 | 3368 | |
b013c399 | 3369 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3370 | old_sigset_t __user *, oset) |
1da177e4 | 3371 | { |
1da177e4 | 3372 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3373 | sigset_t new_blocked; |
1da177e4 | 3374 | |
b013c399 | 3375 | old_set = current->blocked.sig[0]; |
1da177e4 | 3376 | |
b013c399 ON |
3377 | if (nset) { |
3378 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3379 | return -EFAULT; | |
1da177e4 | 3380 | |
2e4f7c77 | 3381 | new_blocked = current->blocked; |
1da177e4 | 3382 | |
1da177e4 | 3383 | switch (how) { |
1da177e4 | 3384 | case SIG_BLOCK: |
2e4f7c77 | 3385 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3386 | break; |
3387 | case SIG_UNBLOCK: | |
2e4f7c77 | 3388 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3389 | break; |
3390 | case SIG_SETMASK: | |
2e4f7c77 | 3391 | new_blocked.sig[0] = new_set; |
1da177e4 | 3392 | break; |
2e4f7c77 ON |
3393 | default: |
3394 | return -EINVAL; | |
1da177e4 LT |
3395 | } |
3396 | ||
0c4a8423 | 3397 | set_current_blocked(&new_blocked); |
b013c399 ON |
3398 | } |
3399 | ||
3400 | if (oset) { | |
1da177e4 | 3401 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3402 | return -EFAULT; |
1da177e4 | 3403 | } |
b013c399 ON |
3404 | |
3405 | return 0; | |
1da177e4 LT |
3406 | } |
3407 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3408 | ||
eaca6eae | 3409 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
3410 | /** |
3411 | * sys_rt_sigaction - alter an action taken by a process | |
3412 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3413 | * @act: new sigaction |
3414 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3415 | * @sigsetsize: size of sigset_t type |
3416 | */ | |
d4e82042 HC |
3417 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3418 | const struct sigaction __user *, act, | |
3419 | struct sigaction __user *, oact, | |
3420 | size_t, sigsetsize) | |
1da177e4 LT |
3421 | { |
3422 | struct k_sigaction new_sa, old_sa; | |
3423 | int ret = -EINVAL; | |
3424 | ||
3425 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3426 | if (sigsetsize != sizeof(sigset_t)) | |
3427 | goto out; | |
3428 | ||
3429 | if (act) { | |
3430 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3431 | return -EFAULT; | |
3432 | } | |
3433 | ||
3434 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3435 | ||
3436 | if (!ret && oact) { | |
3437 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3438 | return -EFAULT; | |
3439 | } | |
3440 | out: | |
3441 | return ret; | |
3442 | } | |
08d32fe5 | 3443 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
3444 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3445 | const struct compat_sigaction __user *, act, | |
3446 | struct compat_sigaction __user *, oact, | |
3447 | compat_size_t, sigsetsize) | |
3448 | { | |
3449 | struct k_sigaction new_ka, old_ka; | |
08d32fe5 AV |
3450 | #ifdef __ARCH_HAS_SA_RESTORER |
3451 | compat_uptr_t restorer; | |
3452 | #endif | |
3453 | int ret; | |
3454 | ||
3455 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3456 | if (sigsetsize != sizeof(compat_sigset_t)) | |
3457 | return -EINVAL; | |
3458 | ||
3459 | if (act) { | |
3460 | compat_uptr_t handler; | |
3461 | ret = get_user(handler, &act->sa_handler); | |
3462 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3463 | #ifdef __ARCH_HAS_SA_RESTORER | |
3464 | ret |= get_user(restorer, &act->sa_restorer); | |
3465 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3466 | #endif | |
3968cf62 | 3467 | ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask); |
3ddc5b46 | 3468 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
3469 | if (ret) |
3470 | return -EFAULT; | |
08d32fe5 AV |
3471 | } |
3472 | ||
3473 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3474 | if (!ret && oact) { | |
08d32fe5 AV |
3475 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), |
3476 | &oact->sa_handler); | |
f454322e DL |
3477 | ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, |
3478 | sizeof(oact->sa_mask)); | |
3ddc5b46 | 3479 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
3480 | #ifdef __ARCH_HAS_SA_RESTORER |
3481 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3482 | &oact->sa_restorer); | |
3483 | #endif | |
3484 | } | |
3485 | return ret; | |
3486 | } | |
3487 | #endif | |
eaca6eae | 3488 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 3489 | |
495dfbf7 AV |
3490 | #ifdef CONFIG_OLD_SIGACTION |
3491 | SYSCALL_DEFINE3(sigaction, int, sig, | |
3492 | const struct old_sigaction __user *, act, | |
3493 | struct old_sigaction __user *, oact) | |
3494 | { | |
3495 | struct k_sigaction new_ka, old_ka; | |
3496 | int ret; | |
3497 | ||
3498 | if (act) { | |
3499 | old_sigset_t mask; | |
3500 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3501 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
3502 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
3503 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3504 | __get_user(mask, &act->sa_mask)) | |
3505 | return -EFAULT; | |
3506 | #ifdef __ARCH_HAS_KA_RESTORER | |
3507 | new_ka.ka_restorer = NULL; | |
3508 | #endif | |
3509 | siginitset(&new_ka.sa.sa_mask, mask); | |
3510 | } | |
3511 | ||
3512 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3513 | ||
3514 | if (!ret && oact) { | |
3515 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3516 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
3517 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
3518 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3519 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3520 | return -EFAULT; | |
3521 | } | |
3522 | ||
3523 | return ret; | |
3524 | } | |
3525 | #endif | |
3526 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
3527 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
3528 | const struct compat_old_sigaction __user *, act, | |
3529 | struct compat_old_sigaction __user *, oact) | |
3530 | { | |
3531 | struct k_sigaction new_ka, old_ka; | |
3532 | int ret; | |
3533 | compat_old_sigset_t mask; | |
3534 | compat_uptr_t handler, restorer; | |
3535 | ||
3536 | if (act) { | |
3537 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3538 | __get_user(handler, &act->sa_handler) || | |
3539 | __get_user(restorer, &act->sa_restorer) || | |
3540 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3541 | __get_user(mask, &act->sa_mask)) | |
3542 | return -EFAULT; | |
3543 | ||
3544 | #ifdef __ARCH_HAS_KA_RESTORER | |
3545 | new_ka.ka_restorer = NULL; | |
3546 | #endif | |
3547 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3548 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3549 | siginitset(&new_ka.sa.sa_mask, mask); | |
3550 | } | |
3551 | ||
3552 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3553 | ||
3554 | if (!ret && oact) { | |
3555 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3556 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3557 | &oact->sa_handler) || | |
3558 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3559 | &oact->sa_restorer) || | |
3560 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3561 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3562 | return -EFAULT; | |
3563 | } | |
3564 | return ret; | |
3565 | } | |
3566 | #endif | |
1da177e4 | 3567 | |
f6187769 | 3568 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
3569 | |
3570 | /* | |
3571 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3572 | */ | |
a5f8fa9e | 3573 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3574 | { |
3575 | /* SMP safe */ | |
3576 | return current->blocked.sig[0]; | |
3577 | } | |
3578 | ||
a5f8fa9e | 3579 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3580 | { |
c1095c6d ON |
3581 | int old = current->blocked.sig[0]; |
3582 | sigset_t newset; | |
1da177e4 | 3583 | |
5ba53ff6 | 3584 | siginitset(&newset, newmask); |
c1095c6d | 3585 | set_current_blocked(&newset); |
1da177e4 LT |
3586 | |
3587 | return old; | |
3588 | } | |
f6187769 | 3589 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
3590 | |
3591 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3592 | /* | |
3593 | * For backwards compatibility. Functionality superseded by sigaction. | |
3594 | */ | |
a5f8fa9e | 3595 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3596 | { |
3597 | struct k_sigaction new_sa, old_sa; | |
3598 | int ret; | |
3599 | ||
3600 | new_sa.sa.sa_handler = handler; | |
3601 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3602 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3603 | |
3604 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3605 | ||
3606 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3607 | } | |
3608 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3609 | ||
3610 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3611 | ||
a5f8fa9e | 3612 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3613 | { |
d92fcf05 | 3614 | while (!signal_pending(current)) { |
1df01355 | 3615 | __set_current_state(TASK_INTERRUPTIBLE); |
d92fcf05 ON |
3616 | schedule(); |
3617 | } | |
1da177e4 LT |
3618 | return -ERESTARTNOHAND; |
3619 | } | |
3620 | ||
3621 | #endif | |
3622 | ||
9d8a7652 | 3623 | static int sigsuspend(sigset_t *set) |
68f3f16d | 3624 | { |
68f3f16d AV |
3625 | current->saved_sigmask = current->blocked; |
3626 | set_current_blocked(set); | |
3627 | ||
823dd322 SL |
3628 | while (!signal_pending(current)) { |
3629 | __set_current_state(TASK_INTERRUPTIBLE); | |
3630 | schedule(); | |
3631 | } | |
68f3f16d AV |
3632 | set_restore_sigmask(); |
3633 | return -ERESTARTNOHAND; | |
3634 | } | |
68f3f16d | 3635 | |
41c57892 RD |
3636 | /** |
3637 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3638 | * @unewset value until a signal is received | |
3639 | * @unewset: new signal mask value | |
3640 | * @sigsetsize: size of sigset_t type | |
3641 | */ | |
d4e82042 | 3642 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3643 | { |
3644 | sigset_t newset; | |
3645 | ||
3646 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3647 | if (sigsetsize != sizeof(sigset_t)) | |
3648 | return -EINVAL; | |
3649 | ||
3650 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3651 | return -EFAULT; | |
68f3f16d | 3652 | return sigsuspend(&newset); |
150256d8 | 3653 | } |
ad4b65a4 AV |
3654 | |
3655 | #ifdef CONFIG_COMPAT | |
3656 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
3657 | { | |
ad4b65a4 | 3658 | sigset_t newset; |
ad4b65a4 AV |
3659 | |
3660 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3661 | if (sigsetsize != sizeof(sigset_t)) | |
3662 | return -EINVAL; | |
3663 | ||
3968cf62 | 3664 | if (get_compat_sigset(&newset, unewset)) |
ad4b65a4 | 3665 | return -EFAULT; |
ad4b65a4 | 3666 | return sigsuspend(&newset); |
ad4b65a4 AV |
3667 | } |
3668 | #endif | |
150256d8 | 3669 | |
0a0e8cdf AV |
3670 | #ifdef CONFIG_OLD_SIGSUSPEND |
3671 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
3672 | { | |
3673 | sigset_t blocked; | |
3674 | siginitset(&blocked, mask); | |
3675 | return sigsuspend(&blocked); | |
3676 | } | |
3677 | #endif | |
3678 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
3679 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
3680 | { | |
3681 | sigset_t blocked; | |
3682 | siginitset(&blocked, mask); | |
3683 | return sigsuspend(&blocked); | |
3684 | } | |
3685 | #endif | |
150256d8 | 3686 | |
52f5684c | 3687 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
3688 | { |
3689 | return NULL; | |
3690 | } | |
3691 | ||
1da177e4 LT |
3692 | void __init signals_init(void) |
3693 | { | |
41b27154 HD |
3694 | /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */ |
3695 | BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE | |
3696 | != offsetof(struct siginfo, _sifields._pad)); | |
3697 | ||
0a31bd5f | 3698 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3699 | } |
67fc4e0c JW |
3700 | |
3701 | #ifdef CONFIG_KGDB_KDB | |
3702 | #include <linux/kdb.h> | |
3703 | /* | |
3704 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3705 | * signal internals. This function checks if the required locks are | |
3706 | * available before calling the main signal code, to avoid kdb | |
3707 | * deadlocks. | |
3708 | */ | |
3709 | void | |
3710 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3711 | { | |
3712 | static struct task_struct *kdb_prev_t; | |
3713 | int sig, new_t; | |
3714 | if (!spin_trylock(&t->sighand->siglock)) { | |
3715 | kdb_printf("Can't do kill command now.\n" | |
3716 | "The sigmask lock is held somewhere else in " | |
3717 | "kernel, try again later\n"); | |
3718 | return; | |
3719 | } | |
3720 | spin_unlock(&t->sighand->siglock); | |
3721 | new_t = kdb_prev_t != t; | |
3722 | kdb_prev_t = t; | |
3723 | if (t->state != TASK_RUNNING && new_t) { | |
3724 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3725 | "kdb risks deadlock\n" | |
3726 | "on the run queue locks. " | |
3727 | "The signal has _not_ been sent.\n" | |
3728 | "Reissue the kill command if you want to risk " | |
3729 | "the deadlock.\n"); | |
3730 | return; | |
3731 | } | |
3732 | sig = info->si_signo; | |
3733 | if (send_sig_info(sig, info, t)) | |
3734 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3735 | sig, t->pid); | |
3736 | else | |
3737 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3738 | } | |
3739 | #endif /* CONFIG_KGDB_KDB */ |