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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 | ||
3177b082 EB |
80 | /* SIGKILL and SIGSTOP may not be sent to the global init */ |
81 | if (unlikely(is_global_init(t) && sig_kernel_only(sig))) | |
82 | return true; | |
83 | ||
f008faff | 84 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && |
ac253850 | 85 | handler == SIG_DFL && !(force && sig_kernel_only(sig))) |
f008faff ON |
86 | return 1; |
87 | ||
6bd82415 EB |
88 | /* Only allow kernel generated signals to this kthread */ |
89 | if (unlikely((t->flags & PF_KTHREAD) && | |
90 | (handler == SIG_KTHREAD_KERNEL) && !force)) | |
91 | return true; | |
92 | ||
f008faff ON |
93 | return sig_handler_ignored(handler, sig); |
94 | } | |
95 | ||
def8cf72 | 96 | static int sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 97 | { |
1da177e4 LT |
98 | /* |
99 | * Blocked signals are never ignored, since the | |
100 | * signal handler may change by the time it is | |
101 | * unblocked. | |
102 | */ | |
325d22df | 103 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
104 | return 0; |
105 | ||
35de254d | 106 | /* |
628c1bcb ON |
107 | * Tracers may want to know about even ignored signal unless it |
108 | * is SIGKILL which can't be reported anyway but can be ignored | |
109 | * by SIGNAL_UNKILLABLE task. | |
35de254d | 110 | */ |
628c1bcb ON |
111 | if (t->ptrace && sig != SIGKILL) |
112 | return 0; | |
113 | ||
114 | return sig_task_ignored(t, sig, force); | |
1da177e4 LT |
115 | } |
116 | ||
117 | /* | |
118 | * Re-calculate pending state from the set of locally pending | |
119 | * signals, globally pending signals, and blocked signals. | |
120 | */ | |
121 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
122 | { | |
123 | unsigned long ready; | |
124 | long i; | |
125 | ||
126 | switch (_NSIG_WORDS) { | |
127 | default: | |
128 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
129 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
130 | break; | |
131 | ||
132 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
133 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
134 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
135 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
136 | break; | |
137 | ||
138 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
139 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
140 | break; | |
141 | ||
142 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
143 | } | |
144 | return ready != 0; | |
145 | } | |
146 | ||
147 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
148 | ||
7bb44ade | 149 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 150 | { |
3759a0d9 | 151 | if ((t->jobctl & JOBCTL_PENDING_MASK) || |
1da177e4 | 152 | PENDING(&t->pending, &t->blocked) || |
7bb44ade | 153 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 154 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
155 | return 1; |
156 | } | |
b74d0deb RM |
157 | /* |
158 | * We must never clear the flag in another thread, or in current | |
159 | * when it's possible the current syscall is returning -ERESTART*. | |
160 | * So we don't clear it here, and only callers who know they should do. | |
161 | */ | |
7bb44ade RM |
162 | return 0; |
163 | } | |
164 | ||
165 | /* | |
166 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
167 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
168 | */ | |
169 | void recalc_sigpending_and_wake(struct task_struct *t) | |
170 | { | |
171 | if (recalc_sigpending_tsk(t)) | |
172 | signal_wake_up(t, 0); | |
1da177e4 LT |
173 | } |
174 | ||
175 | void recalc_sigpending(void) | |
176 | { | |
dd1d6772 | 177 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
178 | clear_thread_flag(TIF_SIGPENDING); |
179 | ||
1da177e4 LT |
180 | } |
181 | ||
182 | /* Given the mask, find the first available signal that should be serviced. */ | |
183 | ||
a27341cd LT |
184 | #define SYNCHRONOUS_MASK \ |
185 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 186 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 187 | |
fba2afaa | 188 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
189 | { |
190 | unsigned long i, *s, *m, x; | |
191 | int sig = 0; | |
f84d49b2 | 192 | |
1da177e4 LT |
193 | s = pending->signal.sig; |
194 | m = mask->sig; | |
a27341cd LT |
195 | |
196 | /* | |
197 | * Handle the first word specially: it contains the | |
198 | * synchronous signals that need to be dequeued first. | |
199 | */ | |
200 | x = *s &~ *m; | |
201 | if (x) { | |
202 | if (x & SYNCHRONOUS_MASK) | |
203 | x &= SYNCHRONOUS_MASK; | |
204 | sig = ffz(~x) + 1; | |
205 | return sig; | |
206 | } | |
207 | ||
1da177e4 LT |
208 | switch (_NSIG_WORDS) { |
209 | default: | |
a27341cd LT |
210 | for (i = 1; i < _NSIG_WORDS; ++i) { |
211 | x = *++s &~ *++m; | |
212 | if (!x) | |
213 | continue; | |
214 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
215 | break; | |
216 | } | |
1da177e4 LT |
217 | break; |
218 | ||
a27341cd LT |
219 | case 2: |
220 | x = s[1] &~ m[1]; | |
221 | if (!x) | |
1da177e4 | 222 | break; |
a27341cd | 223 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
224 | break; |
225 | ||
a27341cd LT |
226 | case 1: |
227 | /* Nothing to do */ | |
1da177e4 LT |
228 | break; |
229 | } | |
f84d49b2 | 230 | |
1da177e4 LT |
231 | return sig; |
232 | } | |
233 | ||
f84d49b2 NO |
234 | static inline void print_dropped_signal(int sig) |
235 | { | |
236 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
237 | ||
238 | if (!print_fatal_signals) | |
239 | return; | |
240 | ||
241 | if (!__ratelimit(&ratelimit_state)) | |
242 | return; | |
243 | ||
747800ef | 244 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
f84d49b2 NO |
245 | current->comm, current->pid, sig); |
246 | } | |
247 | ||
d79fdd6d | 248 | /** |
7dd3db54 | 249 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 250 | * @task: target task |
7dd3db54 | 251 | * @mask: pending bits to set |
d79fdd6d | 252 | * |
7dd3db54 TH |
253 | * Clear @mask from @task->jobctl. @mask must be subset of |
254 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
255 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
256 | * cleared. If @task is already being killed or exiting, this function | |
257 | * becomes noop. | |
258 | * | |
259 | * CONTEXT: | |
260 | * Must be called with @task->sighand->siglock held. | |
261 | * | |
262 | * RETURNS: | |
263 | * %true if @mask is set, %false if made noop because @task was dying. | |
264 | */ | |
b76808e6 | 265 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
7dd3db54 TH |
266 | { |
267 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
268 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
269 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
270 | ||
271 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
272 | return false; | |
273 | ||
274 | if (mask & JOBCTL_STOP_SIGMASK) | |
275 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
276 | ||
277 | task->jobctl |= mask; | |
278 | return true; | |
279 | } | |
280 | ||
d79fdd6d | 281 | /** |
a8f072c1 | 282 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
283 | * @task: target task |
284 | * | |
a8f072c1 TH |
285 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
286 | * Clear it and wake up the ptracer. Note that we don't need any further | |
287 | * locking. @task->siglock guarantees that @task->parent points to the | |
288 | * ptracer. | |
d79fdd6d TH |
289 | * |
290 | * CONTEXT: | |
291 | * Must be called with @task->sighand->siglock held. | |
292 | */ | |
73ddff2b | 293 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 294 | { |
a8f072c1 TH |
295 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
296 | task->jobctl &= ~JOBCTL_TRAPPING; | |
650226bd | 297 | smp_mb(); /* advised by wake_up_bit() */ |
62c124ff | 298 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
299 | } |
300 | } | |
301 | ||
e5c1902e | 302 | /** |
3759a0d9 | 303 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 304 | * @task: target task |
3759a0d9 | 305 | * @mask: pending bits to clear |
e5c1902e | 306 | * |
3759a0d9 TH |
307 | * Clear @mask from @task->jobctl. @mask must be subset of |
308 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
309 | * STOP bits are cleared together. | |
e5c1902e | 310 | * |
6dfca329 TH |
311 | * If clearing of @mask leaves no stop or trap pending, this function calls |
312 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
313 | * |
314 | * CONTEXT: | |
315 | * Must be called with @task->sighand->siglock held. | |
316 | */ | |
b76808e6 | 317 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
e5c1902e | 318 | { |
3759a0d9 TH |
319 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
320 | ||
321 | if (mask & JOBCTL_STOP_PENDING) | |
322 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
323 | ||
324 | task->jobctl &= ~mask; | |
6dfca329 TH |
325 | |
326 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
327 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
328 | } |
329 | ||
330 | /** | |
331 | * task_participate_group_stop - participate in a group stop | |
332 | * @task: task participating in a group stop | |
333 | * | |
a8f072c1 | 334 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 335 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 336 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 337 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
338 | * |
339 | * CONTEXT: | |
340 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
341 | * |
342 | * RETURNS: | |
343 | * %true if group stop completion should be notified to the parent, %false | |
344 | * otherwise. | |
e5c1902e TH |
345 | */ |
346 | static bool task_participate_group_stop(struct task_struct *task) | |
347 | { | |
348 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 349 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 350 | |
a8f072c1 | 351 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 352 | |
3759a0d9 | 353 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
354 | |
355 | if (!consume) | |
356 | return false; | |
357 | ||
358 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
359 | sig->group_stop_count--; | |
360 | ||
244056f9 TH |
361 | /* |
362 | * Tell the caller to notify completion iff we are entering into a | |
363 | * fresh group stop. Read comment in do_signal_stop() for details. | |
364 | */ | |
365 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
2d39b3cd | 366 | signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
e5c1902e TH |
367 | return true; |
368 | } | |
369 | return false; | |
370 | } | |
371 | ||
c69e8d9c DH |
372 | /* |
373 | * allocate a new signal queue record | |
374 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 375 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 376 | */ |
f84d49b2 NO |
377 | static struct sigqueue * |
378 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
379 | { |
380 | struct sigqueue *q = NULL; | |
10b1fbdb | 381 | struct user_struct *user; |
1da177e4 | 382 | |
10b1fbdb | 383 | /* |
7cf7db8d TG |
384 | * Protect access to @t credentials. This can go away when all |
385 | * callers hold rcu read lock. | |
10b1fbdb | 386 | */ |
7cf7db8d | 387 | rcu_read_lock(); |
d84f4f99 | 388 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 389 | atomic_inc(&user->sigpending); |
7cf7db8d | 390 | rcu_read_unlock(); |
f84d49b2 | 391 | |
1da177e4 | 392 | if (override_rlimit || |
10b1fbdb | 393 | atomic_read(&user->sigpending) <= |
78d7d407 | 394 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 395 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
396 | } else { |
397 | print_dropped_signal(sig); | |
398 | } | |
399 | ||
1da177e4 | 400 | if (unlikely(q == NULL)) { |
10b1fbdb | 401 | atomic_dec(&user->sigpending); |
d84f4f99 | 402 | free_uid(user); |
1da177e4 LT |
403 | } else { |
404 | INIT_LIST_HEAD(&q->list); | |
405 | q->flags = 0; | |
d84f4f99 | 406 | q->user = user; |
1da177e4 | 407 | } |
d84f4f99 DH |
408 | |
409 | return q; | |
1da177e4 LT |
410 | } |
411 | ||
514a01b8 | 412 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
413 | { |
414 | if (q->flags & SIGQUEUE_PREALLOC) | |
415 | return; | |
416 | atomic_dec(&q->user->sigpending); | |
417 | free_uid(q->user); | |
418 | kmem_cache_free(sigqueue_cachep, q); | |
419 | } | |
420 | ||
6a14c5c9 | 421 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
422 | { |
423 | struct sigqueue *q; | |
424 | ||
425 | sigemptyset(&queue->signal); | |
426 | while (!list_empty(&queue->list)) { | |
427 | q = list_entry(queue->list.next, struct sigqueue , list); | |
428 | list_del_init(&q->list); | |
429 | __sigqueue_free(q); | |
430 | } | |
431 | } | |
432 | ||
433 | /* | |
9e7c8f8c | 434 | * Flush all pending signals for this kthread. |
1da177e4 | 435 | */ |
c81addc9 | 436 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
437 | { |
438 | unsigned long flags; | |
439 | ||
440 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
9e7c8f8c ON |
441 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
442 | flush_sigqueue(&t->pending); | |
443 | flush_sigqueue(&t->signal->shared_pending); | |
1da177e4 LT |
444 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
445 | } | |
446 | ||
baa73d9e | 447 | #ifdef CONFIG_POSIX_TIMERS |
cbaffba1 ON |
448 | static void __flush_itimer_signals(struct sigpending *pending) |
449 | { | |
450 | sigset_t signal, retain; | |
451 | struct sigqueue *q, *n; | |
452 | ||
453 | signal = pending->signal; | |
454 | sigemptyset(&retain); | |
455 | ||
456 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
457 | int sig = q->info.si_signo; | |
458 | ||
459 | if (likely(q->info.si_code != SI_TIMER)) { | |
460 | sigaddset(&retain, sig); | |
461 | } else { | |
462 | sigdelset(&signal, sig); | |
463 | list_del_init(&q->list); | |
464 | __sigqueue_free(q); | |
465 | } | |
466 | } | |
467 | ||
468 | sigorsets(&pending->signal, &signal, &retain); | |
469 | } | |
470 | ||
471 | void flush_itimer_signals(void) | |
472 | { | |
473 | struct task_struct *tsk = current; | |
474 | unsigned long flags; | |
475 | ||
476 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
477 | __flush_itimer_signals(&tsk->pending); | |
478 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
479 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
480 | } | |
baa73d9e | 481 | #endif |
cbaffba1 | 482 | |
10ab825b ON |
483 | void ignore_signals(struct task_struct *t) |
484 | { | |
485 | int i; | |
486 | ||
487 | for (i = 0; i < _NSIG; ++i) | |
488 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
489 | ||
490 | flush_signals(t); | |
491 | } | |
492 | ||
1da177e4 LT |
493 | /* |
494 | * Flush all handlers for a task. | |
495 | */ | |
496 | ||
497 | void | |
498 | flush_signal_handlers(struct task_struct *t, int force_default) | |
499 | { | |
500 | int i; | |
501 | struct k_sigaction *ka = &t->sighand->action[0]; | |
502 | for (i = _NSIG ; i != 0 ; i--) { | |
503 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
504 | ka->sa.sa_handler = SIG_DFL; | |
505 | ka->sa.sa_flags = 0; | |
522cff14 | 506 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
507 | ka->sa.sa_restorer = NULL; |
508 | #endif | |
1da177e4 LT |
509 | sigemptyset(&ka->sa.sa_mask); |
510 | ka++; | |
511 | } | |
512 | } | |
513 | ||
abd4f750 MAS |
514 | int unhandled_signal(struct task_struct *tsk, int sig) |
515 | { | |
445a91d2 | 516 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 517 | if (is_global_init(tsk)) |
abd4f750 | 518 | return 1; |
445a91d2 | 519 | if (handler != SIG_IGN && handler != SIG_DFL) |
abd4f750 | 520 | return 0; |
a288eecc TH |
521 | /* if ptraced, let the tracer determine */ |
522 | return !tsk->ptrace; | |
abd4f750 MAS |
523 | } |
524 | ||
57db7e4a EB |
525 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info, |
526 | bool *resched_timer) | |
1da177e4 LT |
527 | { |
528 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 529 | |
1da177e4 LT |
530 | /* |
531 | * Collect the siginfo appropriate to this signal. Check if | |
532 | * there is another siginfo for the same signal. | |
533 | */ | |
534 | list_for_each_entry(q, &list->list, list) { | |
535 | if (q->info.si_signo == sig) { | |
d4434207 ON |
536 | if (first) |
537 | goto still_pending; | |
1da177e4 LT |
538 | first = q; |
539 | } | |
540 | } | |
d4434207 ON |
541 | |
542 | sigdelset(&list->signal, sig); | |
543 | ||
1da177e4 | 544 | if (first) { |
d4434207 | 545 | still_pending: |
1da177e4 LT |
546 | list_del_init(&first->list); |
547 | copy_siginfo(info, &first->info); | |
57db7e4a EB |
548 | |
549 | *resched_timer = | |
550 | (first->flags & SIGQUEUE_PREALLOC) && | |
551 | (info->si_code == SI_TIMER) && | |
552 | (info->si_sys_private); | |
553 | ||
1da177e4 | 554 | __sigqueue_free(first); |
1da177e4 | 555 | } else { |
5aba085e RD |
556 | /* |
557 | * Ok, it wasn't in the queue. This must be | |
558 | * a fast-pathed signal or we must have been | |
559 | * out of queue space. So zero out the info. | |
1da177e4 | 560 | */ |
1da177e4 LT |
561 | info->si_signo = sig; |
562 | info->si_errno = 0; | |
7486e5d9 | 563 | info->si_code = SI_USER; |
1da177e4 LT |
564 | info->si_pid = 0; |
565 | info->si_uid = 0; | |
566 | } | |
1da177e4 LT |
567 | } |
568 | ||
569 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
57db7e4a | 570 | siginfo_t *info, bool *resched_timer) |
1da177e4 | 571 | { |
27d91e07 | 572 | int sig = next_signal(pending, mask); |
1da177e4 | 573 | |
2e01fabe | 574 | if (sig) |
57db7e4a | 575 | collect_signal(sig, pending, info, resched_timer); |
1da177e4 LT |
576 | return sig; |
577 | } | |
578 | ||
579 | /* | |
5aba085e | 580 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
581 | * expected to free it. |
582 | * | |
583 | * All callers have to hold the siglock. | |
584 | */ | |
585 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
586 | { | |
57db7e4a | 587 | bool resched_timer = false; |
c5363d03 | 588 | int signr; |
caec4e8d BH |
589 | |
590 | /* We only dequeue private signals from ourselves, we don't let | |
591 | * signalfd steal them | |
592 | */ | |
57db7e4a | 593 | signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer); |
8bfd9a7a | 594 | if (!signr) { |
1da177e4 | 595 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
57db7e4a | 596 | mask, info, &resched_timer); |
baa73d9e | 597 | #ifdef CONFIG_POSIX_TIMERS |
8bfd9a7a TG |
598 | /* |
599 | * itimer signal ? | |
600 | * | |
601 | * itimers are process shared and we restart periodic | |
602 | * itimers in the signal delivery path to prevent DoS | |
603 | * attacks in the high resolution timer case. This is | |
5aba085e | 604 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
605 | * itimers, as the SIGALRM is a legacy signal and only |
606 | * queued once. Changing the restart behaviour to | |
607 | * restart the timer in the signal dequeue path is | |
608 | * reducing the timer noise on heavy loaded !highres | |
609 | * systems too. | |
610 | */ | |
611 | if (unlikely(signr == SIGALRM)) { | |
612 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
613 | ||
614 | if (!hrtimer_is_queued(tmr) && | |
2456e855 | 615 | tsk->signal->it_real_incr != 0) { |
8bfd9a7a TG |
616 | hrtimer_forward(tmr, tmr->base->get_time(), |
617 | tsk->signal->it_real_incr); | |
618 | hrtimer_restart(tmr); | |
619 | } | |
620 | } | |
baa73d9e | 621 | #endif |
8bfd9a7a | 622 | } |
c5363d03 | 623 | |
b8fceee1 | 624 | recalc_sigpending(); |
c5363d03 PE |
625 | if (!signr) |
626 | return 0; | |
627 | ||
628 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
629 | /* |
630 | * Set a marker that we have dequeued a stop signal. Our | |
631 | * caller might release the siglock and then the pending | |
632 | * stop signal it is about to process is no longer in the | |
633 | * pending bitmasks, but must still be cleared by a SIGCONT | |
634 | * (and overruled by a SIGKILL). So those cases clear this | |
635 | * shared flag after we've set it. Note that this flag may | |
636 | * remain set after the signal we return is ignored or | |
637 | * handled. That doesn't matter because its only purpose | |
638 | * is to alert stop-signal processing code when another | |
639 | * processor has come along and cleared the flag. | |
640 | */ | |
a8f072c1 | 641 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 642 | } |
baa73d9e | 643 | #ifdef CONFIG_POSIX_TIMERS |
57db7e4a | 644 | if (resched_timer) { |
1da177e4 LT |
645 | /* |
646 | * Release the siglock to ensure proper locking order | |
647 | * of timer locks outside of siglocks. Note, we leave | |
648 | * irqs disabled here, since the posix-timers code is | |
649 | * about to disable them again anyway. | |
650 | */ | |
651 | spin_unlock(&tsk->sighand->siglock); | |
96fe3b07 | 652 | posixtimer_rearm(info); |
1da177e4 LT |
653 | spin_lock(&tsk->sighand->siglock); |
654 | } | |
baa73d9e | 655 | #endif |
1da177e4 LT |
656 | return signr; |
657 | } | |
658 | ||
659 | /* | |
660 | * Tell a process that it has a new active signal.. | |
661 | * | |
662 | * NOTE! we rely on the previous spin_lock to | |
663 | * lock interrupts for us! We can only be called with | |
664 | * "siglock" held, and the local interrupt must | |
665 | * have been disabled when that got acquired! | |
666 | * | |
667 | * No need to set need_resched since signal event passing | |
668 | * goes through ->blocked | |
669 | */ | |
910ffdb1 | 670 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 671 | { |
1da177e4 | 672 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 673 | /* |
910ffdb1 | 674 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 675 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
676 | * executing another processor and just now entering stopped state. |
677 | * By using wake_up_state, we ensure the process will wake up and | |
678 | * handle its death signal. | |
679 | */ | |
910ffdb1 | 680 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
681 | kick_process(t); |
682 | } | |
683 | ||
beea5868 EB |
684 | static int dequeue_synchronous_signal(siginfo_t *info) |
685 | { | |
686 | struct task_struct *tsk = current; | |
687 | struct sigpending *pending = &tsk->pending; | |
688 | struct sigqueue *q, *sync = NULL; | |
689 | ||
690 | /* | |
691 | * Might a synchronous signal be in the queue? | |
692 | */ | |
693 | if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) | |
694 | return 0; | |
695 | ||
696 | /* | |
697 | * Return the first synchronous signal in the queue. | |
698 | */ | |
699 | list_for_each_entry(q, &pending->list, list) { | |
700 | /* Synchronous signals have a postive si_code */ | |
701 | if ((q->info.si_code > SI_USER) && | |
702 | (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) { | |
703 | sync = q; | |
704 | goto next; | |
705 | } | |
706 | } | |
707 | return 0; | |
708 | next: | |
709 | /* | |
710 | * Check if there is another siginfo for the same signal. | |
711 | */ | |
712 | list_for_each_entry_continue(q, &pending->list, list) { | |
713 | if (q->info.si_signo == sync->info.si_signo) | |
714 | goto still_pending; | |
715 | } | |
716 | ||
717 | sigdelset(&pending->signal, sync->info.si_signo); | |
718 | recalc_sigpending(); | |
719 | still_pending: | |
720 | list_del_init(&sync->list); | |
721 | copy_siginfo(info, &sync->info); | |
722 | __sigqueue_free(sync); | |
723 | return info->si_signo; | |
724 | } | |
725 | ||
71fabd5e GA |
726 | /* |
727 | * Remove signals in mask from the pending set and queue. | |
728 | * Returns 1 if any signals were found. | |
729 | * | |
730 | * All callers must be holding the siglock. | |
71fabd5e | 731 | */ |
c09c1441 | 732 | static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
71fabd5e GA |
733 | { |
734 | struct sigqueue *q, *n; | |
735 | sigset_t m; | |
736 | ||
737 | sigandsets(&m, mask, &s->signal); | |
738 | if (sigisemptyset(&m)) | |
739 | return 0; | |
740 | ||
702a5073 | 741 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
742 | list_for_each_entry_safe(q, n, &s->list, list) { |
743 | if (sigismember(mask, q->info.si_signo)) { | |
744 | list_del_init(&q->list); | |
745 | __sigqueue_free(q); | |
746 | } | |
747 | } | |
748 | return 1; | |
749 | } | |
1da177e4 | 750 | |
614c517d ON |
751 | static inline int is_si_special(const struct siginfo *info) |
752 | { | |
753 | return info <= SEND_SIG_FORCED; | |
754 | } | |
755 | ||
756 | static inline bool si_fromuser(const struct siginfo *info) | |
757 | { | |
758 | return info == SEND_SIG_NOINFO || | |
759 | (!is_si_special(info) && SI_FROMUSER(info)); | |
760 | } | |
761 | ||
39fd3393 SH |
762 | /* |
763 | * called with RCU read lock from check_kill_permission() | |
764 | */ | |
765 | static int kill_ok_by_cred(struct task_struct *t) | |
766 | { | |
767 | const struct cred *cred = current_cred(); | |
768 | const struct cred *tcred = __task_cred(t); | |
769 | ||
5af66203 EB |
770 | if (uid_eq(cred->euid, tcred->suid) || |
771 | uid_eq(cred->euid, tcred->uid) || | |
772 | uid_eq(cred->uid, tcred->suid) || | |
773 | uid_eq(cred->uid, tcred->uid)) | |
39fd3393 SH |
774 | return 1; |
775 | ||
c4a4d603 | 776 | if (ns_capable(tcred->user_ns, CAP_KILL)) |
39fd3393 SH |
777 | return 1; |
778 | ||
779 | return 0; | |
780 | } | |
781 | ||
1da177e4 LT |
782 | /* |
783 | * Bad permissions for sending the signal | |
694f690d | 784 | * - the caller must hold the RCU read lock |
1da177e4 LT |
785 | */ |
786 | static int check_kill_permission(int sig, struct siginfo *info, | |
787 | struct task_struct *t) | |
788 | { | |
2e2ba22e | 789 | struct pid *sid; |
3b5e9e53 ON |
790 | int error; |
791 | ||
7ed20e1a | 792 | if (!valid_signal(sig)) |
3b5e9e53 ON |
793 | return -EINVAL; |
794 | ||
614c517d | 795 | if (!si_fromuser(info)) |
3b5e9e53 | 796 | return 0; |
e54dc243 | 797 | |
3b5e9e53 ON |
798 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
799 | if (error) | |
1da177e4 | 800 | return error; |
3b5e9e53 | 801 | |
065add39 | 802 | if (!same_thread_group(current, t) && |
39fd3393 | 803 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
804 | switch (sig) { |
805 | case SIGCONT: | |
2e2ba22e | 806 | sid = task_session(t); |
2e2ba22e ON |
807 | /* |
808 | * We don't return the error if sid == NULL. The | |
809 | * task was unhashed, the caller must notice this. | |
810 | */ | |
811 | if (!sid || sid == task_session(current)) | |
812 | break; | |
813 | default: | |
814 | return -EPERM; | |
815 | } | |
816 | } | |
c2f0c7c3 | 817 | |
e54dc243 | 818 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
819 | } |
820 | ||
fb1d910c TH |
821 | /** |
822 | * ptrace_trap_notify - schedule trap to notify ptracer | |
823 | * @t: tracee wanting to notify tracer | |
824 | * | |
825 | * This function schedules sticky ptrace trap which is cleared on the next | |
826 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
827 | * ptracer. | |
828 | * | |
544b2c91 TH |
829 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
830 | * ptracer is listening for events, tracee is woken up so that it can | |
831 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
832 | * eventually taken without returning to userland after the existing traps | |
833 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
834 | * |
835 | * CONTEXT: | |
836 | * Must be called with @task->sighand->siglock held. | |
837 | */ | |
838 | static void ptrace_trap_notify(struct task_struct *t) | |
839 | { | |
840 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
841 | assert_spin_locked(&t->sighand->siglock); | |
842 | ||
843 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 844 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
845 | } |
846 | ||
1da177e4 | 847 | /* |
7e695a5e ON |
848 | * Handle magic process-wide effects of stop/continue signals. Unlike |
849 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
850 | * time regardless of blocking, ignoring, or handling. This does the |
851 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
852 | * signals. The process stop is done as a signal action for SIG_DFL. |
853 | * | |
854 | * Returns true if the signal should be actually delivered, otherwise | |
855 | * it should be dropped. | |
1da177e4 | 856 | */ |
403bad72 | 857 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 858 | { |
ad16a460 | 859 | struct signal_struct *signal = p->signal; |
1da177e4 | 860 | struct task_struct *t; |
9490592f | 861 | sigset_t flush; |
1da177e4 | 862 | |
403bad72 | 863 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { |
5fa534c9 | 864 | if (!(signal->flags & SIGNAL_GROUP_EXIT)) |
403bad72 | 865 | return sig == SIGKILL; |
1da177e4 | 866 | /* |
7e695a5e | 867 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 868 | */ |
7e695a5e | 869 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
870 | /* |
871 | * This is a stop signal. Remove SIGCONT from all queues. | |
872 | */ | |
9490592f | 873 | siginitset(&flush, sigmask(SIGCONT)); |
c09c1441 | 874 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 875 | for_each_thread(p, t) |
c09c1441 | 876 | flush_sigqueue_mask(&flush, &t->pending); |
1da177e4 | 877 | } else if (sig == SIGCONT) { |
fc321d2e | 878 | unsigned int why; |
1da177e4 | 879 | /* |
1deac632 | 880 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 881 | */ |
9490592f | 882 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
c09c1441 | 883 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 884 | for_each_thread(p, t) { |
c09c1441 | 885 | flush_sigqueue_mask(&flush, &t->pending); |
3759a0d9 | 886 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
fb1d910c TH |
887 | if (likely(!(t->ptrace & PT_SEIZED))) |
888 | wake_up_state(t, __TASK_STOPPED); | |
889 | else | |
890 | ptrace_trap_notify(t); | |
9490592f | 891 | } |
1da177e4 | 892 | |
fc321d2e ON |
893 | /* |
894 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
895 | * | |
896 | * If we were in the middle of a group stop, we pretend it | |
897 | * was already finished, and then continued. Since SIGCHLD | |
898 | * doesn't queue we report only CLD_STOPPED, as if the next | |
899 | * CLD_CONTINUED was dropped. | |
900 | */ | |
901 | why = 0; | |
ad16a460 | 902 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 903 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 904 | else if (signal->group_stop_count) |
fc321d2e ON |
905 | why |= SIGNAL_CLD_STOPPED; |
906 | ||
907 | if (why) { | |
021e1ae3 | 908 | /* |
ae6d2ed7 | 909 | * The first thread which returns from do_signal_stop() |
021e1ae3 ON |
910 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
911 | * notify its parent. See get_signal_to_deliver(). | |
912 | */ | |
2d39b3cd | 913 | signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
ad16a460 ON |
914 | signal->group_stop_count = 0; |
915 | signal->group_exit_code = 0; | |
1da177e4 | 916 | } |
1da177e4 | 917 | } |
7e695a5e | 918 | |
def8cf72 | 919 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
920 | } |
921 | ||
71f11dc0 ON |
922 | /* |
923 | * Test if P wants to take SIG. After we've checked all threads with this, | |
924 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
925 | * blocking SIG were ruled out because they are not running and already | |
926 | * have pending signals. Such threads will dequeue from the shared queue | |
927 | * as soon as they're available, so putting the signal on the shared queue | |
928 | * will be equivalent to sending it to one such thread. | |
929 | */ | |
930 | static inline int wants_signal(int sig, struct task_struct *p) | |
931 | { | |
932 | if (sigismember(&p->blocked, sig)) | |
933 | return 0; | |
934 | if (p->flags & PF_EXITING) | |
935 | return 0; | |
936 | if (sig == SIGKILL) | |
937 | return 1; | |
938 | if (task_is_stopped_or_traced(p)) | |
939 | return 0; | |
940 | return task_curr(p) || !signal_pending(p); | |
941 | } | |
942 | ||
5fcd835b | 943 | static void complete_signal(int sig, struct task_struct *p, int group) |
71f11dc0 ON |
944 | { |
945 | struct signal_struct *signal = p->signal; | |
946 | struct task_struct *t; | |
947 | ||
948 | /* | |
949 | * Now find a thread we can wake up to take the signal off the queue. | |
950 | * | |
951 | * If the main thread wants the signal, it gets first crack. | |
952 | * Probably the least surprising to the average bear. | |
953 | */ | |
954 | if (wants_signal(sig, p)) | |
955 | t = p; | |
5fcd835b | 956 | else if (!group || thread_group_empty(p)) |
71f11dc0 ON |
957 | /* |
958 | * There is just one thread and it does not need to be woken. | |
959 | * It will dequeue unblocked signals before it runs again. | |
960 | */ | |
961 | return; | |
962 | else { | |
963 | /* | |
964 | * Otherwise try to find a suitable thread. | |
965 | */ | |
966 | t = signal->curr_target; | |
967 | while (!wants_signal(sig, t)) { | |
968 | t = next_thread(t); | |
969 | if (t == signal->curr_target) | |
970 | /* | |
971 | * No thread needs to be woken. | |
972 | * Any eligible threads will see | |
973 | * the signal in the queue soon. | |
974 | */ | |
975 | return; | |
976 | } | |
977 | signal->curr_target = t; | |
978 | } | |
979 | ||
980 | /* | |
981 | * Found a killable thread. If the signal will be fatal, | |
982 | * then start taking the whole group down immediately. | |
983 | */ | |
fae5fa44 | 984 | if (sig_fatal(p, sig) && |
42691579 | 985 | !(signal->flags & SIGNAL_GROUP_EXIT) && |
71f11dc0 | 986 | !sigismember(&t->real_blocked, sig) && |
42691579 | 987 | (sig == SIGKILL || !p->ptrace)) { |
71f11dc0 ON |
988 | /* |
989 | * This signal will be fatal to the whole group. | |
990 | */ | |
991 | if (!sig_kernel_coredump(sig)) { | |
992 | /* | |
993 | * Start a group exit and wake everybody up. | |
994 | * This way we don't have other threads | |
995 | * running and doing things after a slower | |
996 | * thread has the fatal signal pending. | |
997 | */ | |
998 | signal->flags = SIGNAL_GROUP_EXIT; | |
999 | signal->group_exit_code = sig; | |
1000 | signal->group_stop_count = 0; | |
1001 | t = p; | |
1002 | do { | |
6dfca329 | 1003 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
1004 | sigaddset(&t->pending.signal, SIGKILL); |
1005 | signal_wake_up(t, 1); | |
1006 | } while_each_thread(p, t); | |
1007 | return; | |
1008 | } | |
1009 | } | |
1010 | ||
1011 | /* | |
1012 | * The signal is already in the shared-pending queue. | |
1013 | * Tell the chosen thread to wake up and dequeue it. | |
1014 | */ | |
1015 | signal_wake_up(t, sig == SIGKILL); | |
1016 | return; | |
1017 | } | |
1018 | ||
af7fff9c PE |
1019 | static inline int legacy_queue(struct sigpending *signals, int sig) |
1020 | { | |
1021 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
1022 | } | |
1023 | ||
6b550f94 SH |
1024 | #ifdef CONFIG_USER_NS |
1025 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1026 | { | |
1027 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
1028 | return; | |
1029 | ||
1030 | if (SI_FROMKERNEL(info)) | |
1031 | return; | |
1032 | ||
078de5f7 EB |
1033 | rcu_read_lock(); |
1034 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
1035 | make_kuid(current_user_ns(), info->si_uid)); | |
1036 | rcu_read_unlock(); | |
6b550f94 SH |
1037 | } |
1038 | #else | |
1039 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t) | |
1040 | { | |
1041 | return; | |
1042 | } | |
1043 | #endif | |
1044 | ||
7978b567 SB |
1045 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1046 | int group, int from_ancestor_ns) | |
1da177e4 | 1047 | { |
2ca3515a | 1048 | struct sigpending *pending; |
6e65acba | 1049 | struct sigqueue *q; |
7a0aeb14 | 1050 | int override_rlimit; |
6c303d3a | 1051 | int ret = 0, result; |
0a16b607 | 1052 | |
6e65acba | 1053 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1054 | |
6c303d3a | 1055 | result = TRACE_SIGNAL_IGNORED; |
629d362b | 1056 | if (!prepare_signal(sig, t, |
3482f6af | 1057 | from_ancestor_ns || (info == SEND_SIG_PRIV) || (info == SEND_SIG_FORCED))) |
6c303d3a | 1058 | goto ret; |
2ca3515a ON |
1059 | |
1060 | pending = group ? &t->signal->shared_pending : &t->pending; | |
2acb024d PE |
1061 | /* |
1062 | * Short-circuit ignored signals and support queuing | |
1063 | * exactly one non-rt signal, so that we can get more | |
1064 | * detailed information about the cause of the signal. | |
1065 | */ | |
6c303d3a | 1066 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1067 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1068 | goto ret; |
1069 | ||
1070 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 LT |
1071 | /* |
1072 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
1073 | * or SIGKILL. | |
1074 | */ | |
b67a1b9e | 1075 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
1076 | goto out_set; |
1077 | ||
5aba085e RD |
1078 | /* |
1079 | * Real-time signals must be queued if sent by sigqueue, or | |
1080 | * some other real-time mechanism. It is implementation | |
1081 | * defined whether kill() does so. We attempt to do so, on | |
1082 | * the principle of least surprise, but since kill is not | |
1083 | * allowed to fail with EAGAIN when low on memory we just | |
1084 | * make sure at least one signal gets delivered and don't | |
1085 | * pass on the info struct. | |
1086 | */ | |
7a0aeb14 VN |
1087 | if (sig < SIGRTMIN) |
1088 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1089 | else | |
1090 | override_rlimit = 0; | |
1091 | ||
75f296d9 | 1092 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit); |
1da177e4 | 1093 | if (q) { |
2ca3515a | 1094 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1095 | switch ((unsigned long) info) { |
b67a1b9e | 1096 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
1097 | q->info.si_signo = sig; |
1098 | q->info.si_errno = 0; | |
1099 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1100 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1101 | task_active_pid_ns(t)); |
078de5f7 | 1102 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1103 | break; |
b67a1b9e | 1104 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
1105 | q->info.si_signo = sig; |
1106 | q->info.si_errno = 0; | |
1107 | q->info.si_code = SI_KERNEL; | |
1108 | q->info.si_pid = 0; | |
1109 | q->info.si_uid = 0; | |
1110 | break; | |
1111 | default: | |
1112 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1113 | if (from_ancestor_ns) |
1114 | q->info.si_pid = 0; | |
1da177e4 LT |
1115 | break; |
1116 | } | |
6b550f94 SH |
1117 | |
1118 | userns_fixup_signal_uid(&q->info, t); | |
1119 | ||
621d3121 | 1120 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1121 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1122 | /* | |
1123 | * Queue overflow, abort. We may abort if the | |
1124 | * signal was rt and sent by user using something | |
1125 | * other than kill(). | |
1126 | */ | |
6c303d3a ON |
1127 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1128 | ret = -EAGAIN; | |
1129 | goto ret; | |
ba005e1f MH |
1130 | } else { |
1131 | /* | |
1132 | * This is a silent loss of information. We still | |
1133 | * send the signal, but the *info bits are lost. | |
1134 | */ | |
6c303d3a | 1135 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1136 | } |
1da177e4 LT |
1137 | } |
1138 | ||
1139 | out_set: | |
53c30337 | 1140 | signalfd_notify(t, sig); |
2ca3515a | 1141 | sigaddset(&pending->signal, sig); |
4cd4b6d4 | 1142 | complete_signal(sig, t, group); |
6c303d3a ON |
1143 | ret: |
1144 | trace_signal_generate(sig, info, t, group, result); | |
1145 | return ret; | |
1da177e4 LT |
1146 | } |
1147 | ||
7978b567 SB |
1148 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
1149 | int group) | |
1150 | { | |
921cf9f6 SB |
1151 | int from_ancestor_ns = 0; |
1152 | ||
1153 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1154 | from_ancestor_ns = si_fromuser(info) && |
1155 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1156 | #endif |
1157 | ||
1158 | return __send_signal(sig, info, t, group, from_ancestor_ns); | |
7978b567 SB |
1159 | } |
1160 | ||
4aaefee5 | 1161 | static void print_fatal_signal(int signr) |
45807a1d | 1162 | { |
4aaefee5 | 1163 | struct pt_regs *regs = signal_pt_regs(); |
747800ef | 1164 | pr_info("potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1165 | |
ca5cd877 | 1166 | #if defined(__i386__) && !defined(__arch_um__) |
747800ef | 1167 | pr_info("code at %08lx: ", regs->ip); |
45807a1d IM |
1168 | { |
1169 | int i; | |
1170 | for (i = 0; i < 16; i++) { | |
1171 | unsigned char insn; | |
1172 | ||
b45c6e76 AK |
1173 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1174 | break; | |
747800ef | 1175 | pr_cont("%02x ", insn); |
45807a1d IM |
1176 | } |
1177 | } | |
747800ef | 1178 | pr_cont("\n"); |
45807a1d | 1179 | #endif |
3a9f84d3 | 1180 | preempt_disable(); |
45807a1d | 1181 | show_regs(regs); |
3a9f84d3 | 1182 | preempt_enable(); |
45807a1d IM |
1183 | } |
1184 | ||
1185 | static int __init setup_print_fatal_signals(char *str) | |
1186 | { | |
1187 | get_option (&str, &print_fatal_signals); | |
1188 | ||
1189 | return 1; | |
1190 | } | |
1191 | ||
1192 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1193 | |
4cd4b6d4 PE |
1194 | int |
1195 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1196 | { | |
1197 | return send_signal(sig, info, p, 1); | |
1198 | } | |
1199 | ||
1da177e4 LT |
1200 | static int |
1201 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1202 | { | |
4cd4b6d4 | 1203 | return send_signal(sig, info, t, 0); |
1da177e4 LT |
1204 | } |
1205 | ||
4a30debf ON |
1206 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, |
1207 | bool group) | |
1208 | { | |
1209 | unsigned long flags; | |
1210 | int ret = -ESRCH; | |
1211 | ||
1212 | if (lock_task_sighand(p, &flags)) { | |
1213 | ret = send_signal(sig, info, p, group); | |
1214 | unlock_task_sighand(p, &flags); | |
1215 | } | |
1216 | ||
1217 | return ret; | |
1218 | } | |
1219 | ||
1da177e4 LT |
1220 | /* |
1221 | * Force a signal that the process can't ignore: if necessary | |
1222 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1223 | * |
1224 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1225 | * since we do not want to have a signal handler that was blocked | |
1226 | * be invoked when user space had explicitly blocked it. | |
1227 | * | |
80fe728d ON |
1228 | * We don't want to have recursive SIGSEGV's etc, for example, |
1229 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1230 | */ |
1da177e4 LT |
1231 | int |
1232 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
1233 | { | |
1234 | unsigned long int flags; | |
ae74c3b6 LT |
1235 | int ret, blocked, ignored; |
1236 | struct k_sigaction *action; | |
1da177e4 LT |
1237 | |
1238 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1239 | action = &t->sighand->action[sig-1]; |
1240 | ignored = action->sa.sa_handler == SIG_IGN; | |
1241 | blocked = sigismember(&t->blocked, sig); | |
1242 | if (blocked || ignored) { | |
1243 | action->sa.sa_handler = SIG_DFL; | |
1244 | if (blocked) { | |
1245 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1246 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1247 | } |
1da177e4 | 1248 | } |
eb61b591 JI |
1249 | /* |
1250 | * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect | |
1251 | * debugging to leave init killable. | |
1252 | */ | |
1253 | if (action->sa.sa_handler == SIG_DFL && !t->ptrace) | |
80fe728d | 1254 | t->signal->flags &= ~SIGNAL_UNKILLABLE; |
1da177e4 LT |
1255 | ret = specific_send_sig_info(sig, info, t); |
1256 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
1257 | ||
1258 | return ret; | |
1259 | } | |
1260 | ||
1da177e4 LT |
1261 | /* |
1262 | * Nuke all other threads in the group. | |
1263 | */ | |
09faef11 | 1264 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1265 | { |
09faef11 ON |
1266 | struct task_struct *t = p; |
1267 | int count = 0; | |
1da177e4 | 1268 | |
1da177e4 LT |
1269 | p->signal->group_stop_count = 0; |
1270 | ||
09faef11 | 1271 | while_each_thread(p, t) { |
6dfca329 | 1272 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1273 | count++; |
1274 | ||
1275 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1276 | if (t->exit_state) |
1277 | continue; | |
1da177e4 | 1278 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1279 | signal_wake_up(t, 1); |
1280 | } | |
09faef11 ON |
1281 | |
1282 | return count; | |
1da177e4 LT |
1283 | } |
1284 | ||
b8ed374e NK |
1285 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1286 | unsigned long *flags) | |
f63ee72e ON |
1287 | { |
1288 | struct sighand_struct *sighand; | |
1289 | ||
1290 | for (;;) { | |
c41247e1 PM |
1291 | /* |
1292 | * Disable interrupts early to avoid deadlocks. | |
1293 | * See rcu_read_unlock() comment header for details. | |
1294 | */ | |
a841796f PM |
1295 | local_irq_save(*flags); |
1296 | rcu_read_lock(); | |
f63ee72e | 1297 | sighand = rcu_dereference(tsk->sighand); |
a841796f PM |
1298 | if (unlikely(sighand == NULL)) { |
1299 | rcu_read_unlock(); | |
1300 | local_irq_restore(*flags); | |
f63ee72e | 1301 | break; |
a841796f | 1302 | } |
392809b2 ON |
1303 | /* |
1304 | * This sighand can be already freed and even reused, but | |
5f0d5a3a | 1305 | * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which |
392809b2 ON |
1306 | * initializes ->siglock: this slab can't go away, it has |
1307 | * the same object type, ->siglock can't be reinitialized. | |
1308 | * | |
1309 | * We need to ensure that tsk->sighand is still the same | |
1310 | * after we take the lock, we can race with de_thread() or | |
1311 | * __exit_signal(). In the latter case the next iteration | |
1312 | * must see ->sighand == NULL. | |
1313 | */ | |
a841796f PM |
1314 | spin_lock(&sighand->siglock); |
1315 | if (likely(sighand == tsk->sighand)) { | |
1316 | rcu_read_unlock(); | |
f63ee72e | 1317 | break; |
a841796f PM |
1318 | } |
1319 | spin_unlock(&sighand->siglock); | |
1320 | rcu_read_unlock(); | |
1321 | local_irq_restore(*flags); | |
f63ee72e ON |
1322 | } |
1323 | ||
1324 | return sighand; | |
1325 | } | |
1326 | ||
c69e8d9c DH |
1327 | /* |
1328 | * send signal info to all the members of a group | |
c69e8d9c | 1329 | */ |
1da177e4 LT |
1330 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1331 | { | |
694f690d DH |
1332 | int ret; |
1333 | ||
1334 | rcu_read_lock(); | |
1335 | ret = check_kill_permission(sig, info, p); | |
1336 | rcu_read_unlock(); | |
f63ee72e | 1337 | |
4a30debf ON |
1338 | if (!ret && sig) |
1339 | ret = do_send_sig_info(sig, info, p, true); | |
1da177e4 LT |
1340 | |
1341 | return ret; | |
1342 | } | |
1343 | ||
1344 | /* | |
146a505d | 1345 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1346 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1347 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1348 | */ |
c4b92fc1 | 1349 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1350 | { |
1351 | struct task_struct *p = NULL; | |
1352 | int retval, success; | |
1353 | ||
1da177e4 LT |
1354 | success = 0; |
1355 | retval = -ESRCH; | |
c4b92fc1 | 1356 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1357 | int err = group_send_sig_info(sig, info, p); |
1358 | success |= !err; | |
1359 | retval = err; | |
c4b92fc1 | 1360 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1361 | return success ? 0 : retval; |
1362 | } | |
1363 | ||
c4b92fc1 | 1364 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1365 | { |
d36174bc | 1366 | int error = -ESRCH; |
1da177e4 LT |
1367 | struct task_struct *p; |
1368 | ||
eca1a089 PM |
1369 | for (;;) { |
1370 | rcu_read_lock(); | |
1371 | p = pid_task(pid, PIDTYPE_PID); | |
1372 | if (p) | |
1373 | error = group_send_sig_info(sig, info, p); | |
1374 | rcu_read_unlock(); | |
1375 | if (likely(!p || error != -ESRCH)) | |
1376 | return error; | |
6ca25b55 | 1377 | |
eca1a089 PM |
1378 | /* |
1379 | * The task was unhashed in between, try again. If it | |
1380 | * is dead, pid_task() will return NULL, if we race with | |
1381 | * de_thread() it will find the new leader. | |
1382 | */ | |
1383 | } | |
1da177e4 LT |
1384 | } |
1385 | ||
6c478ae9 | 1386 | static int kill_proc_info(int sig, struct siginfo *info, pid_t pid) |
c4b92fc1 EB |
1387 | { |
1388 | int error; | |
1389 | rcu_read_lock(); | |
b488893a | 1390 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1391 | rcu_read_unlock(); |
1392 | return error; | |
1393 | } | |
1394 | ||
d178bc3a SH |
1395 | static int kill_as_cred_perm(const struct cred *cred, |
1396 | struct task_struct *target) | |
1397 | { | |
1398 | const struct cred *pcred = __task_cred(target); | |
5af66203 EB |
1399 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) && |
1400 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid)) | |
d178bc3a SH |
1401 | return 0; |
1402 | return 1; | |
1403 | } | |
1404 | ||
2425c08b | 1405 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
d178bc3a SH |
1406 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid, |
1407 | const struct cred *cred, u32 secid) | |
46113830 HW |
1408 | { |
1409 | int ret = -EINVAL; | |
1410 | struct task_struct *p; | |
14d8c9f3 | 1411 | unsigned long flags; |
46113830 HW |
1412 | |
1413 | if (!valid_signal(sig)) | |
1414 | return ret; | |
1415 | ||
14d8c9f3 | 1416 | rcu_read_lock(); |
2425c08b | 1417 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1418 | if (!p) { |
1419 | ret = -ESRCH; | |
1420 | goto out_unlock; | |
1421 | } | |
d178bc3a | 1422 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1423 | ret = -EPERM; |
1424 | goto out_unlock; | |
1425 | } | |
8f95dc58 DQ |
1426 | ret = security_task_kill(p, info, sig, secid); |
1427 | if (ret) | |
1428 | goto out_unlock; | |
14d8c9f3 TG |
1429 | |
1430 | if (sig) { | |
1431 | if (lock_task_sighand(p, &flags)) { | |
1432 | ret = __send_signal(sig, info, p, 1, 0); | |
1433 | unlock_task_sighand(p, &flags); | |
1434 | } else | |
1435 | ret = -ESRCH; | |
46113830 HW |
1436 | } |
1437 | out_unlock: | |
14d8c9f3 | 1438 | rcu_read_unlock(); |
46113830 HW |
1439 | return ret; |
1440 | } | |
d178bc3a | 1441 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1442 | |
1443 | /* | |
1444 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1445 | * | |
1446 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1447 | * is probably wrong. Should make it like BSD or SYSV. | |
1448 | */ | |
1449 | ||
bc64efd2 | 1450 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid) |
1da177e4 | 1451 | { |
8d42db18 | 1452 | int ret; |
d5df763b PE |
1453 | |
1454 | if (pid > 0) { | |
1455 | rcu_read_lock(); | |
1456 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1457 | rcu_read_unlock(); | |
1458 | return ret; | |
1459 | } | |
1460 | ||
4ea77014 | 1461 | /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */ |
1462 | if (pid == INT_MIN) | |
1463 | return -ESRCH; | |
1464 | ||
d5df763b PE |
1465 | read_lock(&tasklist_lock); |
1466 | if (pid != -1) { | |
1467 | ret = __kill_pgrp_info(sig, info, | |
1468 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1469 | } else { | |
1da177e4 LT |
1470 | int retval = 0, count = 0; |
1471 | struct task_struct * p; | |
1472 | ||
1da177e4 | 1473 | for_each_process(p) { |
d25141a8 SB |
1474 | if (task_pid_vnr(p) > 1 && |
1475 | !same_thread_group(p, current)) { | |
1da177e4 LT |
1476 | int err = group_send_sig_info(sig, info, p); |
1477 | ++count; | |
1478 | if (err != -EPERM) | |
1479 | retval = err; | |
1480 | } | |
1481 | } | |
8d42db18 | 1482 | ret = count ? retval : -ESRCH; |
1da177e4 | 1483 | } |
d5df763b PE |
1484 | read_unlock(&tasklist_lock); |
1485 | ||
8d42db18 | 1486 | return ret; |
1da177e4 LT |
1487 | } |
1488 | ||
1489 | /* | |
1490 | * These are for backward compatibility with the rest of the kernel source. | |
1491 | */ | |
1492 | ||
5aba085e | 1493 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1da177e4 | 1494 | { |
1da177e4 LT |
1495 | /* |
1496 | * Make sure legacy kernel users don't send in bad values | |
1497 | * (normal paths check this in check_kill_permission). | |
1498 | */ | |
7ed20e1a | 1499 | if (!valid_signal(sig)) |
1da177e4 LT |
1500 | return -EINVAL; |
1501 | ||
4a30debf | 1502 | return do_send_sig_info(sig, info, p, false); |
1da177e4 LT |
1503 | } |
1504 | ||
b67a1b9e ON |
1505 | #define __si_special(priv) \ |
1506 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1507 | ||
1da177e4 LT |
1508 | int |
1509 | send_sig(int sig, struct task_struct *p, int priv) | |
1510 | { | |
b67a1b9e | 1511 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1512 | } |
1513 | ||
1da177e4 LT |
1514 | void |
1515 | force_sig(int sig, struct task_struct *p) | |
1516 | { | |
b67a1b9e | 1517 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1518 | } |
1519 | ||
1520 | /* | |
1521 | * When things go south during signal handling, we | |
1522 | * will force a SIGSEGV. And if the signal that caused | |
1523 | * the problem was already a SIGSEGV, we'll want to | |
1524 | * make sure we don't even try to deliver the signal.. | |
1525 | */ | |
1526 | int | |
1527 | force_sigsegv(int sig, struct task_struct *p) | |
1528 | { | |
1529 | if (sig == SIGSEGV) { | |
1530 | unsigned long flags; | |
1531 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1532 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1533 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1534 | } | |
1535 | force_sig(SIGSEGV, p); | |
1536 | return 0; | |
1537 | } | |
1538 | ||
c4b92fc1 EB |
1539 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1540 | { | |
146a505d PE |
1541 | int ret; |
1542 | ||
1543 | read_lock(&tasklist_lock); | |
1544 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1545 | read_unlock(&tasklist_lock); | |
1546 | ||
1547 | return ret; | |
c4b92fc1 EB |
1548 | } |
1549 | EXPORT_SYMBOL(kill_pgrp); | |
1550 | ||
1551 | int kill_pid(struct pid *pid, int sig, int priv) | |
1552 | { | |
1553 | return kill_pid_info(sig, __si_special(priv), pid); | |
1554 | } | |
1555 | EXPORT_SYMBOL(kill_pid); | |
1556 | ||
1da177e4 LT |
1557 | /* |
1558 | * These functions support sending signals using preallocated sigqueue | |
1559 | * structures. This is needed "because realtime applications cannot | |
1560 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1561 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1562 | * we allocate the sigqueue structure from the timer_create. If this |
1563 | * allocation fails we are able to report the failure to the application | |
1564 | * with an EAGAIN error. | |
1565 | */ | |
1da177e4 LT |
1566 | struct sigqueue *sigqueue_alloc(void) |
1567 | { | |
f84d49b2 | 1568 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1569 | |
f84d49b2 | 1570 | if (q) |
1da177e4 | 1571 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1572 | |
1573 | return q; | |
1da177e4 LT |
1574 | } |
1575 | ||
1576 | void sigqueue_free(struct sigqueue *q) | |
1577 | { | |
1578 | unsigned long flags; | |
60187d27 ON |
1579 | spinlock_t *lock = ¤t->sighand->siglock; |
1580 | ||
1da177e4 LT |
1581 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1582 | /* | |
c8e85b4f ON |
1583 | * We must hold ->siglock while testing q->list |
1584 | * to serialize with collect_signal() or with | |
da7978b0 | 1585 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1586 | */ |
60187d27 | 1587 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1588 | q->flags &= ~SIGQUEUE_PREALLOC; |
1589 | /* | |
1590 | * If it is queued it will be freed when dequeued, | |
1591 | * like the "regular" sigqueue. | |
1592 | */ | |
60187d27 | 1593 | if (!list_empty(&q->list)) |
c8e85b4f | 1594 | q = NULL; |
60187d27 ON |
1595 | spin_unlock_irqrestore(lock, flags); |
1596 | ||
c8e85b4f ON |
1597 | if (q) |
1598 | __sigqueue_free(q); | |
1da177e4 LT |
1599 | } |
1600 | ||
ac5c2153 | 1601 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) |
9e3bd6c3 | 1602 | { |
e62e6650 | 1603 | int sig = q->info.si_signo; |
2ca3515a | 1604 | struct sigpending *pending; |
e62e6650 | 1605 | unsigned long flags; |
163566f6 | 1606 | int ret, result; |
2ca3515a | 1607 | |
4cd4b6d4 | 1608 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1609 | |
1610 | ret = -1; | |
1611 | if (!likely(lock_task_sighand(t, &flags))) | |
1612 | goto ret; | |
1613 | ||
7e695a5e | 1614 | ret = 1; /* the signal is ignored */ |
163566f6 | 1615 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1616 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1617 | goto out; |
1618 | ||
1619 | ret = 0; | |
9e3bd6c3 PE |
1620 | if (unlikely(!list_empty(&q->list))) { |
1621 | /* | |
1622 | * If an SI_TIMER entry is already queue just increment | |
1623 | * the overrun count. | |
1624 | */ | |
9e3bd6c3 PE |
1625 | BUG_ON(q->info.si_code != SI_TIMER); |
1626 | q->info.si_overrun++; | |
163566f6 | 1627 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1628 | goto out; |
9e3bd6c3 | 1629 | } |
ba661292 | 1630 | q->info.si_overrun = 0; |
9e3bd6c3 | 1631 | |
9e3bd6c3 | 1632 | signalfd_notify(t, sig); |
2ca3515a | 1633 | pending = group ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1634 | list_add_tail(&q->list, &pending->list); |
1635 | sigaddset(&pending->signal, sig); | |
4cd4b6d4 | 1636 | complete_signal(sig, t, group); |
163566f6 | 1637 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1638 | out: |
163566f6 | 1639 | trace_signal_generate(sig, &q->info, t, group, result); |
e62e6650 ON |
1640 | unlock_task_sighand(t, &flags); |
1641 | ret: | |
1642 | return ret; | |
9e3bd6c3 PE |
1643 | } |
1644 | ||
1da177e4 LT |
1645 | /* |
1646 | * Let a parent know about the death of a child. | |
1647 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1648 | * |
53c8f9f1 ON |
1649 | * Returns true if our parent ignored us and so we've switched to |
1650 | * self-reaping. | |
1da177e4 | 1651 | */ |
53c8f9f1 | 1652 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 LT |
1653 | { |
1654 | struct siginfo info; | |
1655 | unsigned long flags; | |
1656 | struct sighand_struct *psig; | |
53c8f9f1 | 1657 | bool autoreap = false; |
bde8285e | 1658 | u64 utime, stime; |
1da177e4 LT |
1659 | |
1660 | BUG_ON(sig == -1); | |
1661 | ||
1662 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1663 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1664 | |
d21142ec | 1665 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1666 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1667 | ||
b6e238dc ON |
1668 | if (sig != SIGCHLD) { |
1669 | /* | |
1670 | * This is only possible if parent == real_parent. | |
1671 | * Check if it has changed security domain. | |
1672 | */ | |
1673 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1674 | sig = SIGCHLD; | |
1675 | } | |
1676 | ||
1da177e4 LT |
1677 | info.si_signo = sig; |
1678 | info.si_errno = 0; | |
b488893a | 1679 | /* |
32084504 EB |
1680 | * We are under tasklist_lock here so our parent is tied to |
1681 | * us and cannot change. | |
b488893a | 1682 | * |
32084504 EB |
1683 | * task_active_pid_ns will always return the same pid namespace |
1684 | * until a task passes through release_task. | |
b488893a PE |
1685 | * |
1686 | * write_lock() currently calls preempt_disable() which is the | |
1687 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1688 | * correct to rely on this | |
1689 | */ | |
1690 | rcu_read_lock(); | |
32084504 | 1691 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1692 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1693 | task_uid(tsk)); | |
b488893a PE |
1694 | rcu_read_unlock(); |
1695 | ||
bde8285e FW |
1696 | task_cputime(tsk, &utime, &stime); |
1697 | info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); | |
1698 | info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1699 | |
1700 | info.si_status = tsk->exit_code & 0x7f; | |
1701 | if (tsk->exit_code & 0x80) | |
1702 | info.si_code = CLD_DUMPED; | |
1703 | else if (tsk->exit_code & 0x7f) | |
1704 | info.si_code = CLD_KILLED; | |
1705 | else { | |
1706 | info.si_code = CLD_EXITED; | |
1707 | info.si_status = tsk->exit_code >> 8; | |
1708 | } | |
1709 | ||
1710 | psig = tsk->parent->sighand; | |
1711 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1712 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1713 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1714 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1715 | /* | |
1716 | * We are exiting and our parent doesn't care. POSIX.1 | |
1717 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1718 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1719 | * automatically and not left for our parent's wait4 call. | |
1720 | * Rather than having the parent do it as a magic kind of | |
1721 | * signal handler, we just set this to tell do_exit that we | |
1722 | * can be cleaned up without becoming a zombie. Note that | |
1723 | * we still call __wake_up_parent in this case, because a | |
1724 | * blocked sys_wait4 might now return -ECHILD. | |
1725 | * | |
1726 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1727 | * is implementation-defined: we do (if you don't want | |
1728 | * it, just use SIG_IGN instead). | |
1729 | */ | |
53c8f9f1 | 1730 | autoreap = true; |
1da177e4 | 1731 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1732 | sig = 0; |
1da177e4 | 1733 | } |
53c8f9f1 | 1734 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1735 | __group_send_sig_info(sig, &info, tsk->parent); |
1736 | __wake_up_parent(tsk, tsk->parent); | |
1737 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1738 | |
53c8f9f1 | 1739 | return autoreap; |
1da177e4 LT |
1740 | } |
1741 | ||
75b95953 TH |
1742 | /** |
1743 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1744 | * @tsk: task reporting the state change | |
1745 | * @for_ptracer: the notification is for ptracer | |
1746 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1747 | * | |
1748 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1749 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1750 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1751 | * | |
1752 | * CONTEXT: | |
1753 | * Must be called with tasklist_lock at least read locked. | |
1754 | */ | |
1755 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1756 | bool for_ptracer, int why) | |
1da177e4 LT |
1757 | { |
1758 | struct siginfo info; | |
1759 | unsigned long flags; | |
bc505a47 | 1760 | struct task_struct *parent; |
1da177e4 | 1761 | struct sighand_struct *sighand; |
bde8285e | 1762 | u64 utime, stime; |
1da177e4 | 1763 | |
75b95953 | 1764 | if (for_ptracer) { |
bc505a47 | 1765 | parent = tsk->parent; |
75b95953 | 1766 | } else { |
bc505a47 ON |
1767 | tsk = tsk->group_leader; |
1768 | parent = tsk->real_parent; | |
1769 | } | |
1770 | ||
1da177e4 LT |
1771 | info.si_signo = SIGCHLD; |
1772 | info.si_errno = 0; | |
b488893a | 1773 | /* |
5aba085e | 1774 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1775 | */ |
1776 | rcu_read_lock(); | |
17cf22c3 | 1777 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1778 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1779 | rcu_read_unlock(); |
1780 | ||
bde8285e FW |
1781 | task_cputime(tsk, &utime, &stime); |
1782 | info.si_utime = nsec_to_clock_t(utime); | |
1783 | info.si_stime = nsec_to_clock_t(stime); | |
1da177e4 LT |
1784 | |
1785 | info.si_code = why; | |
1786 | switch (why) { | |
1787 | case CLD_CONTINUED: | |
1788 | info.si_status = SIGCONT; | |
1789 | break; | |
1790 | case CLD_STOPPED: | |
1791 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1792 | break; | |
1793 | case CLD_TRAPPED: | |
1794 | info.si_status = tsk->exit_code & 0x7f; | |
1795 | break; | |
1796 | default: | |
1797 | BUG(); | |
1798 | } | |
1799 | ||
1800 | sighand = parent->sighand; | |
1801 | spin_lock_irqsave(&sighand->siglock, flags); | |
1802 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1803 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1804 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1805 | /* | |
1806 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1807 | */ | |
1808 | __wake_up_parent(tsk, parent); | |
1809 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1810 | } | |
1811 | ||
d5f70c00 ON |
1812 | static inline int may_ptrace_stop(void) |
1813 | { | |
d21142ec | 1814 | if (!likely(current->ptrace)) |
d5f70c00 | 1815 | return 0; |
d5f70c00 ON |
1816 | /* |
1817 | * Are we in the middle of do_coredump? | |
1818 | * If so and our tracer is also part of the coredump stopping | |
1819 | * is a deadlock situation, and pointless because our tracer | |
1820 | * is dead so don't allow us to stop. | |
1821 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1822 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1823 | * is safe to enter schedule(). |
9899d11f ON |
1824 | * |
1825 | * This is almost outdated, a task with the pending SIGKILL can't | |
1826 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1827 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1828 | */ |
999d9fc1 | 1829 | if (unlikely(current->mm->core_state) && |
d5f70c00 ON |
1830 | unlikely(current->mm == current->parent->mm)) |
1831 | return 0; | |
1832 | ||
1833 | return 1; | |
1834 | } | |
1835 | ||
1a669c2f | 1836 | /* |
5aba085e | 1837 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
1838 | * Called with the siglock held. |
1839 | */ | |
1840 | static int sigkill_pending(struct task_struct *tsk) | |
1841 | { | |
3d749b9e ON |
1842 | return sigismember(&tsk->pending.signal, SIGKILL) || |
1843 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
1844 | } |
1845 | ||
1da177e4 LT |
1846 | /* |
1847 | * This must be called with current->sighand->siglock held. | |
1848 | * | |
1849 | * This should be the path for all ptrace stops. | |
1850 | * We always set current->last_siginfo while stopped here. | |
1851 | * That makes it a way to test a stopped process for | |
1852 | * being ptrace-stopped vs being job-control-stopped. | |
1853 | * | |
20686a30 ON |
1854 | * If we actually decide not to stop at all because the tracer |
1855 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1856 | */ |
fe1bc6a0 | 1857 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) |
b8401150 NK |
1858 | __releases(¤t->sighand->siglock) |
1859 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 1860 | { |
ceb6bd67 TH |
1861 | bool gstop_done = false; |
1862 | ||
1a669c2f RM |
1863 | if (arch_ptrace_stop_needed(exit_code, info)) { |
1864 | /* | |
1865 | * The arch code has something special to do before a | |
1866 | * ptrace stop. This is allowed to block, e.g. for faults | |
1867 | * on user stack pages. We can't keep the siglock while | |
1868 | * calling arch_ptrace_stop, so we must release it now. | |
1869 | * To preserve proper semantics, we must do this before | |
1870 | * any signal bookkeeping like checking group_stop_count. | |
1871 | * Meanwhile, a SIGKILL could come in before we retake the | |
1872 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1873 | * So after regaining the lock, we must check for SIGKILL. | |
1874 | */ | |
1875 | spin_unlock_irq(¤t->sighand->siglock); | |
1876 | arch_ptrace_stop(exit_code, info); | |
1877 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
1878 | if (sigkill_pending(current)) |
1879 | return; | |
1a669c2f RM |
1880 | } |
1881 | ||
ea19cfd1 PZ |
1882 | set_special_state(TASK_TRACED); |
1883 | ||
1da177e4 | 1884 | /* |
81be24b8 TH |
1885 | * We're committing to trapping. TRACED should be visible before |
1886 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
1887 | * Also, transition to TRACED and updates to ->jobctl should be | |
1888 | * atomic with respect to siglock and should be done after the arch | |
1889 | * hook as siglock is released and regrabbed across it. | |
ea19cfd1 PZ |
1890 | * |
1891 | * TRACER TRACEE | |
1892 | * | |
1893 | * ptrace_attach() | |
1894 | * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED) | |
1895 | * do_wait() | |
1896 | * set_current_state() smp_wmb(); | |
1897 | * ptrace_do_wait() | |
1898 | * wait_task_stopped() | |
1899 | * task_stopped_code() | |
1900 | * [L] task_is_traced() [S] task_clear_jobctl_trapping(); | |
1da177e4 | 1901 | */ |
ea19cfd1 | 1902 | smp_wmb(); |
1da177e4 LT |
1903 | |
1904 | current->last_siginfo = info; | |
1905 | current->exit_code = exit_code; | |
1906 | ||
d79fdd6d | 1907 | /* |
0ae8ce1c TH |
1908 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
1909 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
1910 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
1911 | * could be clear now. We act as if SIGCONT is received after | |
1912 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 1913 | */ |
a8f072c1 | 1914 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 1915 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 1916 | |
fb1d910c | 1917 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 1918 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
1919 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
1920 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 1921 | |
81be24b8 | 1922 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 1923 | task_clear_jobctl_trapping(current); |
d79fdd6d | 1924 | |
1da177e4 LT |
1925 | spin_unlock_irq(¤t->sighand->siglock); |
1926 | read_lock(&tasklist_lock); | |
3d749b9e | 1927 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
1928 | /* |
1929 | * Notify parents of the stop. | |
1930 | * | |
1931 | * While ptraced, there are two parents - the ptracer and | |
1932 | * the real_parent of the group_leader. The ptracer should | |
1933 | * know about every stop while the real parent is only | |
1934 | * interested in the completion of group stop. The states | |
1935 | * for the two don't interact with each other. Notify | |
1936 | * separately unless they're gonna be duplicates. | |
1937 | */ | |
1938 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 1939 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
1940 | do_notify_parent_cldstop(current, false, why); |
1941 | ||
53da1d94 MS |
1942 | /* |
1943 | * Don't want to allow preemption here, because | |
1944 | * sys_ptrace() needs this task to be inactive. | |
1945 | * | |
1946 | * XXX: implement read_unlock_no_resched(). | |
1947 | */ | |
1948 | preempt_disable(); | |
1da177e4 | 1949 | read_unlock(&tasklist_lock); |
53da1d94 | 1950 | preempt_enable_no_resched(); |
5d8f72b5 | 1951 | freezable_schedule(); |
1da177e4 LT |
1952 | } else { |
1953 | /* | |
1954 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1955 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
1956 | * |
1957 | * If @gstop_done, the ptracer went away between group stop | |
1958 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
1959 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
1960 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
1961 | * the real parent of the group stop completion is enough. | |
1da177e4 | 1962 | */ |
ceb6bd67 TH |
1963 | if (gstop_done) |
1964 | do_notify_parent_cldstop(current, false, why); | |
1965 | ||
9899d11f | 1966 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 1967 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1968 | if (clear_code) |
1969 | current->exit_code = 0; | |
6405f7f4 | 1970 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1971 | } |
1972 | ||
1973 | /* | |
1974 | * We are back. Now reacquire the siglock before touching | |
1975 | * last_siginfo, so that we are sure to have synchronized with | |
1976 | * any signal-sending on another CPU that wants to examine it. | |
1977 | */ | |
1978 | spin_lock_irq(¤t->sighand->siglock); | |
1979 | current->last_siginfo = NULL; | |
1980 | ||
544b2c91 TH |
1981 | /* LISTENING can be set only during STOP traps, clear it */ |
1982 | current->jobctl &= ~JOBCTL_LISTENING; | |
1983 | ||
1da177e4 LT |
1984 | /* |
1985 | * Queued signals ignored us while we were stopped for tracing. | |
1986 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1987 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1988 | */ |
b74d0deb | 1989 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1990 | } |
1991 | ||
3544d72a | 1992 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 LT |
1993 | { |
1994 | siginfo_t info; | |
1995 | ||
1da177e4 | 1996 | memset(&info, 0, sizeof info); |
3544d72a | 1997 | info.si_signo = signr; |
1da177e4 | 1998 | info.si_code = exit_code; |
b488893a | 1999 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 2000 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2001 | |
2002 | /* Let the debugger run. */ | |
3544d72a TH |
2003 | ptrace_stop(exit_code, why, 1, &info); |
2004 | } | |
2005 | ||
2006 | void ptrace_notify(int exit_code) | |
2007 | { | |
2008 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
2009 | if (unlikely(current->task_works)) |
2010 | task_work_run(); | |
3544d72a | 2011 | |
1da177e4 | 2012 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 2013 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
2014 | spin_unlock_irq(¤t->sighand->siglock); |
2015 | } | |
2016 | ||
73ddff2b TH |
2017 | /** |
2018 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
2019 | * @signr: signr causing group stop if initiating | |
2020 | * | |
2021 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
2022 | * and participate in it. If already set, participate in the existing | |
2023 | * group stop. If participated in a group stop (and thus slept), %true is | |
2024 | * returned with siglock released. | |
2025 | * | |
2026 | * If ptraced, this function doesn't handle stop itself. Instead, | |
2027 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
2028 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
2029 | * places afterwards. | |
2030 | * | |
2031 | * CONTEXT: | |
2032 | * Must be called with @current->sighand->siglock held, which is released | |
2033 | * on %true return. | |
2034 | * | |
2035 | * RETURNS: | |
2036 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
2037 | * %true if participated in group stop. | |
1da177e4 | 2038 | */ |
73ddff2b TH |
2039 | static bool do_signal_stop(int signr) |
2040 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
2041 | { |
2042 | struct signal_struct *sig = current->signal; | |
1da177e4 | 2043 | |
a8f072c1 | 2044 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
b76808e6 | 2045 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
f558b7e4 ON |
2046 | struct task_struct *t; |
2047 | ||
a8f072c1 TH |
2048 | /* signr will be recorded in task->jobctl for retries */ |
2049 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 2050 | |
a8f072c1 | 2051 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 2052 | unlikely(signal_group_exit(sig))) |
73ddff2b | 2053 | return false; |
1da177e4 | 2054 | /* |
408a37de TH |
2055 | * There is no group stop already in progress. We must |
2056 | * initiate one now. | |
2057 | * | |
2058 | * While ptraced, a task may be resumed while group stop is | |
2059 | * still in effect and then receive a stop signal and | |
2060 | * initiate another group stop. This deviates from the | |
2061 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2062 | * cause two group stops when !ptraced. That is why we |
2063 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2064 | * |
2065 | * The condition can be distinguished by testing whether | |
2066 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2067 | * group_exit_code in such case. | |
2068 | * | |
2069 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2070 | * an intervening stop signal is required to cause two | |
2071 | * continued events regardless of ptrace. | |
1da177e4 | 2072 | */ |
408a37de TH |
2073 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2074 | sig->group_exit_code = signr; | |
1da177e4 | 2075 | |
7dd3db54 TH |
2076 | sig->group_stop_count = 0; |
2077 | ||
2078 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2079 | sig->group_stop_count++; | |
1da177e4 | 2080 | |
8d38f203 ON |
2081 | t = current; |
2082 | while_each_thread(current, t) { | |
1da177e4 | 2083 | /* |
a122b341 ON |
2084 | * Setting state to TASK_STOPPED for a group |
2085 | * stop is always done with the siglock held, | |
2086 | * so this check has no races. | |
1da177e4 | 2087 | */ |
7dd3db54 TH |
2088 | if (!task_is_stopped(t) && |
2089 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2090 | sig->group_stop_count++; |
fb1d910c TH |
2091 | if (likely(!(t->ptrace & PT_SEIZED))) |
2092 | signal_wake_up(t, 0); | |
2093 | else | |
2094 | ptrace_trap_notify(t); | |
a122b341 | 2095 | } |
d79fdd6d | 2096 | } |
1da177e4 | 2097 | } |
73ddff2b | 2098 | |
d21142ec | 2099 | if (likely(!current->ptrace)) { |
5224fa36 | 2100 | int notify = 0; |
1da177e4 | 2101 | |
5224fa36 TH |
2102 | /* |
2103 | * If there are no other threads in the group, or if there | |
2104 | * is a group stop in progress and we are the last to stop, | |
2105 | * report to the parent. | |
2106 | */ | |
2107 | if (task_participate_group_stop(current)) | |
2108 | notify = CLD_STOPPED; | |
2109 | ||
ea19cfd1 | 2110 | set_special_state(TASK_STOPPED); |
5224fa36 TH |
2111 | spin_unlock_irq(¤t->sighand->siglock); |
2112 | ||
62bcf9d9 TH |
2113 | /* |
2114 | * Notify the parent of the group stop completion. Because | |
2115 | * we're not holding either the siglock or tasklist_lock | |
2116 | * here, ptracer may attach inbetween; however, this is for | |
2117 | * group stop and should always be delivered to the real | |
2118 | * parent of the group leader. The new ptracer will get | |
2119 | * its notification when this task transitions into | |
2120 | * TASK_TRACED. | |
2121 | */ | |
5224fa36 TH |
2122 | if (notify) { |
2123 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2124 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2125 | read_unlock(&tasklist_lock); |
2126 | } | |
2127 | ||
2128 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
5d8f72b5 | 2129 | freezable_schedule(); |
73ddff2b | 2130 | return true; |
d79fdd6d | 2131 | } else { |
73ddff2b TH |
2132 | /* |
2133 | * While ptraced, group stop is handled by STOP trap. | |
2134 | * Schedule it and let the caller deal with it. | |
2135 | */ | |
2136 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2137 | return false; | |
ae6d2ed7 | 2138 | } |
73ddff2b | 2139 | } |
1da177e4 | 2140 | |
73ddff2b TH |
2141 | /** |
2142 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2143 | * | |
3544d72a TH |
2144 | * When PT_SEIZED, it's used for both group stop and explicit |
2145 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2146 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2147 | * the stop signal; otherwise, %SIGTRAP. | |
2148 | * | |
2149 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2150 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2151 | * |
2152 | * CONTEXT: | |
2153 | * Must be called with @current->sighand->siglock held, which may be | |
2154 | * released and re-acquired before returning with intervening sleep. | |
2155 | */ | |
2156 | static void do_jobctl_trap(void) | |
2157 | { | |
3544d72a | 2158 | struct signal_struct *signal = current->signal; |
73ddff2b | 2159 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2160 | |
3544d72a TH |
2161 | if (current->ptrace & PT_SEIZED) { |
2162 | if (!signal->group_stop_count && | |
2163 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2164 | signr = SIGTRAP; | |
2165 | WARN_ON_ONCE(!signr); | |
2166 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2167 | CLD_STOPPED); | |
2168 | } else { | |
2169 | WARN_ON_ONCE(!signr); | |
2170 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2171 | current->exit_code = 0; | |
ae6d2ed7 | 2172 | } |
1da177e4 LT |
2173 | } |
2174 | ||
94eb22d5 | 2175 | static int ptrace_signal(int signr, siginfo_t *info) |
18c98b65 | 2176 | { |
8a352418 ON |
2177 | /* |
2178 | * We do not check sig_kernel_stop(signr) but set this marker | |
2179 | * unconditionally because we do not know whether debugger will | |
2180 | * change signr. This flag has no meaning unless we are going | |
2181 | * to stop after return from ptrace_stop(). In this case it will | |
2182 | * be checked in do_signal_stop(), we should only stop if it was | |
2183 | * not cleared by SIGCONT while we were sleeping. See also the | |
2184 | * comment in dequeue_signal(). | |
2185 | */ | |
2186 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2187 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2188 | |
2189 | /* We're back. Did the debugger cancel the sig? */ | |
2190 | signr = current->exit_code; | |
2191 | if (signr == 0) | |
2192 | return signr; | |
2193 | ||
2194 | current->exit_code = 0; | |
2195 | ||
5aba085e RD |
2196 | /* |
2197 | * Update the siginfo structure if the signal has | |
2198 | * changed. If the debugger wanted something | |
2199 | * specific in the siginfo structure then it should | |
2200 | * have updated *info via PTRACE_SETSIGINFO. | |
2201 | */ | |
18c98b65 RM |
2202 | if (signr != info->si_signo) { |
2203 | info->si_signo = signr; | |
2204 | info->si_errno = 0; | |
2205 | info->si_code = SI_USER; | |
6b550f94 | 2206 | rcu_read_lock(); |
18c98b65 | 2207 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2208 | info->si_uid = from_kuid_munged(current_user_ns(), |
2209 | task_uid(current->parent)); | |
6b550f94 | 2210 | rcu_read_unlock(); |
18c98b65 RM |
2211 | } |
2212 | ||
2213 | /* If the (new) signal is now blocked, requeue it. */ | |
2214 | if (sigismember(¤t->blocked, signr)) { | |
2215 | specific_send_sig_info(signr, info, current); | |
2216 | signr = 0; | |
2217 | } | |
2218 | ||
2219 | return signr; | |
2220 | } | |
2221 | ||
828b1f65 | 2222 | int get_signal(struct ksignal *ksig) |
1da177e4 | 2223 | { |
f6b76d4f ON |
2224 | struct sighand_struct *sighand = current->sighand; |
2225 | struct signal_struct *signal = current->signal; | |
2226 | int signr; | |
1da177e4 | 2227 | |
f784e8a7 ON |
2228 | if (unlikely(current->task_works)) |
2229 | task_work_run(); | |
72667028 | 2230 | |
0326f5a9 SD |
2231 | if (unlikely(uprobe_deny_signal())) |
2232 | return 0; | |
2233 | ||
13b1c3d4 | 2234 | /* |
5d8f72b5 ON |
2235 | * Do this once, we can't return to user-mode if freezing() == T. |
2236 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2237 | * thus do not need another check after return. | |
13b1c3d4 | 2238 | */ |
fc558a74 RW |
2239 | try_to_freeze(); |
2240 | ||
5d8f72b5 | 2241 | relock: |
f6b76d4f | 2242 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2243 | /* |
2244 | * Every stopped thread goes here after wakeup. Check to see if | |
2245 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2246 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2247 | */ | |
f6b76d4f | 2248 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2249 | int why; |
2250 | ||
2251 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2252 | why = CLD_CONTINUED; | |
2253 | else | |
2254 | why = CLD_STOPPED; | |
2255 | ||
f6b76d4f | 2256 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2257 | |
ae6d2ed7 | 2258 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2259 | |
ceb6bd67 TH |
2260 | /* |
2261 | * Notify the parent that we're continuing. This event is | |
2262 | * always per-process and doesn't make whole lot of sense | |
2263 | * for ptracers, who shouldn't consume the state via | |
2264 | * wait(2) either, but, for backward compatibility, notify | |
2265 | * the ptracer of the group leader too unless it's gonna be | |
2266 | * a duplicate. | |
2267 | */ | |
edf2ed15 | 2268 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2269 | do_notify_parent_cldstop(current, false, why); |
2270 | ||
bb3696da ON |
2271 | if (ptrace_reparented(current->group_leader)) |
2272 | do_notify_parent_cldstop(current->group_leader, | |
2273 | true, why); | |
edf2ed15 | 2274 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2275 | |
e4420551 ON |
2276 | goto relock; |
2277 | } | |
2278 | ||
d0841a81 | 2279 | /* Has this task already been marked for death? */ |
70fc9b3b EB |
2280 | if (signal_group_exit(signal)) { |
2281 | ksig->info.si_signo = signr = SIGKILL; | |
2282 | sigdelset(¤t->pending.signal, SIGKILL); | |
62d26f4e ZW |
2283 | trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, |
2284 | &sighand->action[SIGKILL - 1]); | |
70fc9b3b | 2285 | recalc_sigpending(); |
d0841a81 | 2286 | goto fatal; |
70fc9b3b | 2287 | } |
d0841a81 | 2288 | |
1da177e4 LT |
2289 | for (;;) { |
2290 | struct k_sigaction *ka; | |
1be53963 | 2291 | |
dd1d6772 TH |
2292 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2293 | do_signal_stop(0)) | |
7bcf6a2c | 2294 | goto relock; |
1be53963 | 2295 | |
73ddff2b TH |
2296 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) { |
2297 | do_jobctl_trap(); | |
2298 | spin_unlock_irq(&sighand->siglock); | |
2299 | goto relock; | |
2300 | } | |
1da177e4 | 2301 | |
beea5868 EB |
2302 | /* |
2303 | * Signals generated by the execution of an instruction | |
2304 | * need to be delivered before any other pending signals | |
2305 | * so that the instruction pointer in the signal stack | |
2306 | * frame points to the faulting instruction. | |
2307 | */ | |
2308 | signr = dequeue_synchronous_signal(&ksig->info); | |
2309 | if (!signr) | |
2310 | signr = dequeue_signal(current, ¤t->blocked, &ksig->info); | |
7bcf6a2c | 2311 | |
dd1d6772 TH |
2312 | if (!signr) |
2313 | break; /* will return 0 */ | |
7bcf6a2c | 2314 | |
8a352418 | 2315 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
828b1f65 | 2316 | signr = ptrace_signal(signr, &ksig->info); |
dd1d6772 TH |
2317 | if (!signr) |
2318 | continue; | |
1da177e4 LT |
2319 | } |
2320 | ||
dd1d6772 TH |
2321 | ka = &sighand->action[signr-1]; |
2322 | ||
f9d4257e | 2323 | /* Trace actually delivered signals. */ |
828b1f65 | 2324 | trace_signal_deliver(signr, &ksig->info, ka); |
f9d4257e | 2325 | |
1da177e4 LT |
2326 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2327 | continue; | |
2328 | if (ka->sa.sa_handler != SIG_DFL) { | |
2329 | /* Run the handler. */ | |
828b1f65 | 2330 | ksig->ka = *ka; |
1da177e4 LT |
2331 | |
2332 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2333 | ka->sa.sa_handler = SIG_DFL; | |
2334 | ||
2335 | break; /* will return non-zero "signr" value */ | |
2336 | } | |
2337 | ||
2338 | /* | |
2339 | * Now we are doing the default action for this signal. | |
2340 | */ | |
2341 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2342 | continue; | |
2343 | ||
84d73786 | 2344 | /* |
0fbc26a6 | 2345 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2346 | * Container-init gets no signals it doesn't want from same |
2347 | * container. | |
2348 | * | |
2349 | * Note that if global/container-init sees a sig_kernel_only() | |
2350 | * signal here, the signal must have been generated internally | |
2351 | * or must have come from an ancestor namespace. In either | |
2352 | * case, the signal cannot be dropped. | |
84d73786 | 2353 | */ |
fae5fa44 | 2354 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2355 | !sig_kernel_only(signr)) |
1da177e4 LT |
2356 | continue; |
2357 | ||
2358 | if (sig_kernel_stop(signr)) { | |
2359 | /* | |
2360 | * The default action is to stop all threads in | |
2361 | * the thread group. The job control signals | |
2362 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2363 | * always works. Note that siglock needs to be | |
2364 | * dropped during the call to is_orphaned_pgrp() | |
2365 | * because of lock ordering with tasklist_lock. | |
2366 | * This allows an intervening SIGCONT to be posted. | |
2367 | * We need to check for that and bail out if necessary. | |
2368 | */ | |
2369 | if (signr != SIGSTOP) { | |
f6b76d4f | 2370 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2371 | |
2372 | /* signals can be posted during this window */ | |
2373 | ||
3e7cd6c4 | 2374 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2375 | goto relock; |
2376 | ||
f6b76d4f | 2377 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2378 | } |
2379 | ||
828b1f65 | 2380 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
1da177e4 LT |
2381 | /* It released the siglock. */ |
2382 | goto relock; | |
2383 | } | |
2384 | ||
2385 | /* | |
2386 | * We didn't actually stop, due to a race | |
2387 | * with SIGCONT or something like that. | |
2388 | */ | |
2389 | continue; | |
2390 | } | |
2391 | ||
d0841a81 | 2392 | fatal: |
f6b76d4f | 2393 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2394 | |
2395 | /* | |
2396 | * Anything else is fatal, maybe with a core dump. | |
2397 | */ | |
2398 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2399 | |
1da177e4 | 2400 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2401 | if (print_fatal_signals) |
828b1f65 | 2402 | print_fatal_signal(ksig->info.si_signo); |
2b5faa4c | 2403 | proc_coredump_connector(current); |
1da177e4 LT |
2404 | /* |
2405 | * If it was able to dump core, this kills all | |
2406 | * other threads in the group and synchronizes with | |
2407 | * their demise. If we lost the race with another | |
2408 | * thread getting here, it set group_exit_code | |
2409 | * first and our do_group_exit call below will use | |
2410 | * that value and ignore the one we pass it. | |
2411 | */ | |
828b1f65 | 2412 | do_coredump(&ksig->info); |
1da177e4 LT |
2413 | } |
2414 | ||
2415 | /* | |
2416 | * Death signals, no core dump. | |
2417 | */ | |
828b1f65 | 2418 | do_group_exit(ksig->info.si_signo); |
1da177e4 LT |
2419 | /* NOTREACHED */ |
2420 | } | |
f6b76d4f | 2421 | spin_unlock_irq(&sighand->siglock); |
828b1f65 RW |
2422 | |
2423 | ksig->sig = signr; | |
2424 | return ksig->sig > 0; | |
1da177e4 LT |
2425 | } |
2426 | ||
5e6292c0 | 2427 | /** |
efee984c | 2428 | * signal_delivered - |
10b1c7ac | 2429 | * @ksig: kernel signal struct |
efee984c | 2430 | * @stepping: nonzero if debugger single-step or block-step in use |
5e6292c0 | 2431 | * |
e227867f | 2432 | * This function should be called when a signal has successfully been |
10b1c7ac | 2433 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
efee984c | 2434 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER |
10b1c7ac | 2435 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
5e6292c0 | 2436 | */ |
10b1c7ac | 2437 | static void signal_delivered(struct ksignal *ksig, int stepping) |
5e6292c0 MF |
2438 | { |
2439 | sigset_t blocked; | |
2440 | ||
a610d6e6 AV |
2441 | /* A signal was successfully delivered, and the |
2442 | saved sigmask was stored on the signal frame, | |
2443 | and will be restored by sigreturn. So we can | |
2444 | simply clear the restore sigmask flag. */ | |
2445 | clear_restore_sigmask(); | |
2446 | ||
10b1c7ac RW |
2447 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
2448 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) | |
2449 | sigaddset(&blocked, ksig->sig); | |
5e6292c0 | 2450 | set_current_blocked(&blocked); |
df5601f9 | 2451 | tracehook_signal_handler(stepping); |
5e6292c0 MF |
2452 | } |
2453 | ||
2ce5da17 AV |
2454 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2455 | { | |
2456 | if (failed) | |
2457 | force_sigsegv(ksig->sig, current); | |
2458 | else | |
10b1c7ac | 2459 | signal_delivered(ksig, stepping); |
2ce5da17 AV |
2460 | } |
2461 | ||
0edceb7b ON |
2462 | /* |
2463 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2464 | * group-wide signal. Other threads should be notified now to take |
2465 | * the shared signals in @which since we will not. | |
0edceb7b | 2466 | */ |
f646e227 | 2467 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2468 | { |
f646e227 | 2469 | sigset_t retarget; |
0edceb7b ON |
2470 | struct task_struct *t; |
2471 | ||
f646e227 ON |
2472 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2473 | if (sigisemptyset(&retarget)) | |
2474 | return; | |
2475 | ||
0edceb7b ON |
2476 | t = tsk; |
2477 | while_each_thread(tsk, t) { | |
fec9993d ON |
2478 | if (t->flags & PF_EXITING) |
2479 | continue; | |
2480 | ||
2481 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2482 | continue; | |
2483 | /* Remove the signals this thread can handle. */ | |
2484 | sigandsets(&retarget, &retarget, &t->blocked); | |
2485 | ||
2486 | if (!signal_pending(t)) | |
2487 | signal_wake_up(t, 0); | |
2488 | ||
2489 | if (sigisemptyset(&retarget)) | |
2490 | break; | |
0edceb7b ON |
2491 | } |
2492 | } | |
2493 | ||
d12619b5 ON |
2494 | void exit_signals(struct task_struct *tsk) |
2495 | { | |
2496 | int group_stop = 0; | |
f646e227 | 2497 | sigset_t unblocked; |
d12619b5 | 2498 | |
77e4ef99 TH |
2499 | /* |
2500 | * @tsk is about to have PF_EXITING set - lock out users which | |
2501 | * expect stable threadgroup. | |
2502 | */ | |
780de9dd | 2503 | cgroup_threadgroup_change_begin(tsk); |
77e4ef99 | 2504 | |
5dee1707 ON |
2505 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2506 | tsk->flags |= PF_EXITING; | |
780de9dd | 2507 | cgroup_threadgroup_change_end(tsk); |
5dee1707 | 2508 | return; |
d12619b5 ON |
2509 | } |
2510 | ||
5dee1707 | 2511 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2512 | /* |
2513 | * From now this task is not visible for group-wide signals, | |
2514 | * see wants_signal(), do_signal_stop(). | |
2515 | */ | |
2516 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2517 | |
780de9dd | 2518 | cgroup_threadgroup_change_end(tsk); |
77e4ef99 | 2519 | |
5dee1707 ON |
2520 | if (!signal_pending(tsk)) |
2521 | goto out; | |
2522 | ||
f646e227 ON |
2523 | unblocked = tsk->blocked; |
2524 | signotset(&unblocked); | |
2525 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2526 | |
a8f072c1 | 2527 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2528 | task_participate_group_stop(tsk)) |
edf2ed15 | 2529 | group_stop = CLD_STOPPED; |
5dee1707 | 2530 | out: |
d12619b5 ON |
2531 | spin_unlock_irq(&tsk->sighand->siglock); |
2532 | ||
62bcf9d9 TH |
2533 | /* |
2534 | * If group stop has completed, deliver the notification. This | |
2535 | * should always go to the real parent of the group leader. | |
2536 | */ | |
ae6d2ed7 | 2537 | if (unlikely(group_stop)) { |
d12619b5 | 2538 | read_lock(&tasklist_lock); |
62bcf9d9 | 2539 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2540 | read_unlock(&tasklist_lock); |
2541 | } | |
2542 | } | |
2543 | ||
1da177e4 LT |
2544 | EXPORT_SYMBOL(recalc_sigpending); |
2545 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
2546 | EXPORT_SYMBOL(flush_signals); | |
2547 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
2548 | EXPORT_SYMBOL(send_sig); |
2549 | EXPORT_SYMBOL(send_sig_info); | |
2550 | EXPORT_SYMBOL(sigprocmask); | |
1da177e4 LT |
2551 | |
2552 | /* | |
2553 | * System call entry points. | |
2554 | */ | |
2555 | ||
41c57892 RD |
2556 | /** |
2557 | * sys_restart_syscall - restart a system call | |
2558 | */ | |
754fe8d2 | 2559 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 | 2560 | { |
f56141e3 | 2561 | struct restart_block *restart = ¤t->restart_block; |
1da177e4 LT |
2562 | return restart->fn(restart); |
2563 | } | |
2564 | ||
2565 | long do_no_restart_syscall(struct restart_block *param) | |
2566 | { | |
2567 | return -EINTR; | |
2568 | } | |
2569 | ||
b182801a ON |
2570 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2571 | { | |
2572 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2573 | sigset_t newblocked; | |
2574 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2575 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2576 | retarget_shared_pending(tsk, &newblocked); |
2577 | } | |
2578 | tsk->blocked = *newset; | |
2579 | recalc_sigpending(); | |
2580 | } | |
2581 | ||
e6fa16ab ON |
2582 | /** |
2583 | * set_current_blocked - change current->blocked mask | |
2584 | * @newset: new mask | |
2585 | * | |
2586 | * It is wrong to change ->blocked directly, this helper should be used | |
2587 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2588 | */ |
77097ae5 AV |
2589 | void set_current_blocked(sigset_t *newset) |
2590 | { | |
77097ae5 | 2591 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2592 | __set_current_blocked(newset); |
77097ae5 AV |
2593 | } |
2594 | ||
2595 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2596 | { |
2597 | struct task_struct *tsk = current; | |
2598 | ||
c7be96af WL |
2599 | /* |
2600 | * In case the signal mask hasn't changed, there is nothing we need | |
2601 | * to do. The current->blocked shouldn't be modified by other task. | |
2602 | */ | |
2603 | if (sigequalsets(&tsk->blocked, newset)) | |
2604 | return; | |
2605 | ||
e6fa16ab | 2606 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2607 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2608 | spin_unlock_irq(&tsk->sighand->siglock); |
2609 | } | |
1da177e4 LT |
2610 | |
2611 | /* | |
2612 | * This is also useful for kernel threads that want to temporarily | |
2613 | * (or permanently) block certain signals. | |
2614 | * | |
2615 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2616 | * interface happily blocks "unblockable" signals like SIGKILL | |
2617 | * and friends. | |
2618 | */ | |
2619 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2620 | { | |
73ef4aeb ON |
2621 | struct task_struct *tsk = current; |
2622 | sigset_t newset; | |
1da177e4 | 2623 | |
73ef4aeb | 2624 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2625 | if (oldset) |
73ef4aeb | 2626 | *oldset = tsk->blocked; |
a26fd335 | 2627 | |
1da177e4 LT |
2628 | switch (how) { |
2629 | case SIG_BLOCK: | |
73ef4aeb | 2630 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2631 | break; |
2632 | case SIG_UNBLOCK: | |
702a5073 | 2633 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2634 | break; |
2635 | case SIG_SETMASK: | |
73ef4aeb | 2636 | newset = *set; |
1da177e4 LT |
2637 | break; |
2638 | default: | |
73ef4aeb | 2639 | return -EINVAL; |
1da177e4 | 2640 | } |
a26fd335 | 2641 | |
77097ae5 | 2642 | __set_current_blocked(&newset); |
73ef4aeb | 2643 | return 0; |
1da177e4 LT |
2644 | } |
2645 | ||
41c57892 RD |
2646 | /** |
2647 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2648 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2649 | * @nset: stores pending signals |
41c57892 RD |
2650 | * @oset: previous value of signal mask if non-null |
2651 | * @sigsetsize: size of sigset_t type | |
2652 | */ | |
bb7efee2 | 2653 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2654 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2655 | { |
1da177e4 | 2656 | sigset_t old_set, new_set; |
bb7efee2 | 2657 | int error; |
1da177e4 LT |
2658 | |
2659 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2660 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2661 | return -EINVAL; |
1da177e4 | 2662 | |
bb7efee2 ON |
2663 | old_set = current->blocked; |
2664 | ||
2665 | if (nset) { | |
2666 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2667 | return -EFAULT; | |
1da177e4 LT |
2668 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2669 | ||
bb7efee2 | 2670 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2671 | if (error) |
bb7efee2 ON |
2672 | return error; |
2673 | } | |
1da177e4 | 2674 | |
bb7efee2 ON |
2675 | if (oset) { |
2676 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2677 | return -EFAULT; | |
1da177e4 | 2678 | } |
bb7efee2 ON |
2679 | |
2680 | return 0; | |
1da177e4 LT |
2681 | } |
2682 | ||
322a56cb | 2683 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2684 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2685 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2686 | { |
322a56cb AV |
2687 | sigset_t old_set = current->blocked; |
2688 | ||
2689 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2690 | if (sigsetsize != sizeof(sigset_t)) | |
2691 | return -EINVAL; | |
2692 | ||
2693 | if (nset) { | |
322a56cb AV |
2694 | sigset_t new_set; |
2695 | int error; | |
3968cf62 | 2696 | if (get_compat_sigset(&new_set, nset)) |
322a56cb | 2697 | return -EFAULT; |
322a56cb AV |
2698 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2699 | ||
2700 | error = sigprocmask(how, &new_set, NULL); | |
2701 | if (error) | |
2702 | return error; | |
2703 | } | |
f454322e | 2704 | return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; |
322a56cb AV |
2705 | } |
2706 | #endif | |
1da177e4 | 2707 | |
176826af | 2708 | static int do_sigpending(sigset_t *set) |
1da177e4 | 2709 | { |
1da177e4 | 2710 | spin_lock_irq(¤t->sighand->siglock); |
fe9c1db2 | 2711 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
2712 | ¤t->signal->shared_pending.signal); |
2713 | spin_unlock_irq(¤t->sighand->siglock); | |
2714 | ||
2715 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 AV |
2716 | sigandsets(set, ¤t->blocked, set); |
2717 | return 0; | |
5aba085e | 2718 | } |
1da177e4 | 2719 | |
41c57892 RD |
2720 | /** |
2721 | * sys_rt_sigpending - examine a pending signal that has been raised | |
2722 | * while blocked | |
20f22ab4 | 2723 | * @uset: stores pending signals |
41c57892 RD |
2724 | * @sigsetsize: size of sigset_t type or larger |
2725 | */ | |
fe9c1db2 | 2726 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 2727 | { |
fe9c1db2 | 2728 | sigset_t set; |
176826af DL |
2729 | int err; |
2730 | ||
2731 | if (sigsetsize > sizeof(*uset)) | |
2732 | return -EINVAL; | |
2733 | ||
2734 | err = do_sigpending(&set); | |
fe9c1db2 AV |
2735 | if (!err && copy_to_user(uset, &set, sigsetsize)) |
2736 | err = -EFAULT; | |
2737 | return err; | |
2738 | } | |
2739 | ||
2740 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
2741 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
2742 | compat_size_t, sigsetsize) | |
1da177e4 | 2743 | { |
fe9c1db2 | 2744 | sigset_t set; |
176826af DL |
2745 | int err; |
2746 | ||
2747 | if (sigsetsize > sizeof(*uset)) | |
2748 | return -EINVAL; | |
2749 | ||
2750 | err = do_sigpending(&set); | |
f454322e DL |
2751 | if (!err) |
2752 | err = put_compat_sigset(uset, &set, sigsetsize); | |
fe9c1db2 | 2753 | return err; |
1da177e4 | 2754 | } |
fe9c1db2 | 2755 | #endif |
1da177e4 | 2756 | |
9cbc4a39 | 2757 | enum siginfo_layout siginfo_layout(unsigned sig, int si_code) |
cc731525 EB |
2758 | { |
2759 | enum siginfo_layout layout = SIL_KILL; | |
2760 | if ((si_code > SI_USER) && (si_code < SI_KERNEL)) { | |
2761 | static const struct { | |
2762 | unsigned char limit, layout; | |
2763 | } filter[] = { | |
2764 | [SIGILL] = { NSIGILL, SIL_FAULT }, | |
2765 | [SIGFPE] = { NSIGFPE, SIL_FAULT }, | |
2766 | [SIGSEGV] = { NSIGSEGV, SIL_FAULT }, | |
2767 | [SIGBUS] = { NSIGBUS, SIL_FAULT }, | |
2768 | [SIGTRAP] = { NSIGTRAP, SIL_FAULT }, | |
c3aff086 | 2769 | #if defined(SIGEMT) && defined(NSIGEMT) |
cc731525 EB |
2770 | [SIGEMT] = { NSIGEMT, SIL_FAULT }, |
2771 | #endif | |
2772 | [SIGCHLD] = { NSIGCHLD, SIL_CHLD }, | |
2773 | [SIGPOLL] = { NSIGPOLL, SIL_POLL }, | |
2774 | #ifdef __ARCH_SIGSYS | |
2775 | [SIGSYS] = { NSIGSYS, SIL_SYS }, | |
2776 | #endif | |
2777 | }; | |
2778 | if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) | |
2779 | layout = filter[sig].layout; | |
2780 | else if (si_code <= NSIGPOLL) | |
2781 | layout = SIL_POLL; | |
2782 | } else { | |
2783 | if (si_code == SI_TIMER) | |
2784 | layout = SIL_TIMER; | |
2785 | else if (si_code == SI_SIGIO) | |
2786 | layout = SIL_POLL; | |
2787 | else if (si_code < 0) | |
2788 | layout = SIL_RT; | |
2789 | /* Tests to support buggy kernel ABIs */ | |
2790 | #ifdef TRAP_FIXME | |
2791 | if ((sig == SIGTRAP) && (si_code == TRAP_FIXME)) | |
2792 | layout = SIL_FAULT; | |
2793 | #endif | |
2794 | #ifdef FPE_FIXME | |
2795 | if ((sig == SIGFPE) && (si_code == FPE_FIXME)) | |
2796 | layout = SIL_FAULT; | |
2797 | #endif | |
2798 | } | |
2799 | return layout; | |
2800 | } | |
2801 | ||
1da177e4 LT |
2802 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER |
2803 | ||
ce395960 | 2804 | int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) |
1da177e4 LT |
2805 | { |
2806 | int err; | |
2807 | ||
2808 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2809 | return -EFAULT; | |
2810 | if (from->si_code < 0) | |
2811 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2812 | ? -EFAULT : 0; | |
2813 | /* | |
2814 | * If you change siginfo_t structure, please be sure | |
2815 | * this code is fixed accordingly. | |
fba2afaa DL |
2816 | * Please remember to update the signalfd_copyinfo() function |
2817 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2818 | * It should never copy any pad contained in the structure |
2819 | * to avoid security leaks, but must copy the generic | |
2820 | * 3 ints plus the relevant union member. | |
2821 | */ | |
2822 | err = __put_user(from->si_signo, &to->si_signo); | |
2823 | err |= __put_user(from->si_errno, &to->si_errno); | |
cc731525 EB |
2824 | err |= __put_user(from->si_code, &to->si_code); |
2825 | switch (siginfo_layout(from->si_signo, from->si_code)) { | |
2826 | case SIL_KILL: | |
1da177e4 LT |
2827 | err |= __put_user(from->si_pid, &to->si_pid); |
2828 | err |= __put_user(from->si_uid, &to->si_uid); | |
2829 | break; | |
cc731525 EB |
2830 | case SIL_TIMER: |
2831 | /* Unreached SI_TIMER is negative */ | |
1da177e4 | 2832 | break; |
cc731525 | 2833 | case SIL_POLL: |
1da177e4 LT |
2834 | err |= __put_user(from->si_band, &to->si_band); |
2835 | err |= __put_user(from->si_fd, &to->si_fd); | |
2836 | break; | |
cc731525 | 2837 | case SIL_FAULT: |
1da177e4 LT |
2838 | err |= __put_user(from->si_addr, &to->si_addr); |
2839 | #ifdef __ARCH_SI_TRAPNO | |
2840 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
a337fdac AK |
2841 | #endif |
2842 | #ifdef BUS_MCEERR_AO | |
5aba085e | 2843 | /* |
a337fdac | 2844 | * Other callers might not initialize the si_lsb field, |
5aba085e | 2845 | * so check explicitly for the right codes here. |
a337fdac | 2846 | */ |
26135022 AA |
2847 | if (from->si_signo == SIGBUS && |
2848 | (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) | |
a337fdac | 2849 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); |
ee1b58d3 QR |
2850 | #endif |
2851 | #ifdef SEGV_BNDERR | |
26135022 AA |
2852 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) { |
2853 | err |= __put_user(from->si_lower, &to->si_lower); | |
2854 | err |= __put_user(from->si_upper, &to->si_upper); | |
2855 | } | |
cd0ea35f DH |
2856 | #endif |
2857 | #ifdef SEGV_PKUERR | |
2858 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR) | |
2859 | err |= __put_user(from->si_pkey, &to->si_pkey); | |
1da177e4 LT |
2860 | #endif |
2861 | break; | |
cc731525 | 2862 | case SIL_CHLD: |
1da177e4 LT |
2863 | err |= __put_user(from->si_pid, &to->si_pid); |
2864 | err |= __put_user(from->si_uid, &to->si_uid); | |
2865 | err |= __put_user(from->si_status, &to->si_status); | |
2866 | err |= __put_user(from->si_utime, &to->si_utime); | |
2867 | err |= __put_user(from->si_stime, &to->si_stime); | |
2868 | break; | |
cc731525 | 2869 | case SIL_RT: |
1da177e4 LT |
2870 | err |= __put_user(from->si_pid, &to->si_pid); |
2871 | err |= __put_user(from->si_uid, &to->si_uid); | |
2872 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2873 | break; | |
a0727e8c | 2874 | #ifdef __ARCH_SIGSYS |
cc731525 | 2875 | case SIL_SYS: |
a0727e8c WD |
2876 | err |= __put_user(from->si_call_addr, &to->si_call_addr); |
2877 | err |= __put_user(from->si_syscall, &to->si_syscall); | |
2878 | err |= __put_user(from->si_arch, &to->si_arch); | |
2879 | break; | |
2880 | #endif | |
1da177e4 LT |
2881 | } |
2882 | return err; | |
2883 | } | |
2884 | ||
2885 | #endif | |
2886 | ||
943df148 ON |
2887 | /** |
2888 | * do_sigtimedwait - wait for queued signals specified in @which | |
2889 | * @which: queued signals to wait for | |
2890 | * @info: if non-null, the signal's siginfo is returned here | |
2891 | * @ts: upper bound on process time suspension | |
2892 | */ | |
1b3c872c | 2893 | static int do_sigtimedwait(const sigset_t *which, siginfo_t *info, |
2b1ecc3d | 2894 | const struct timespec *ts) |
943df148 | 2895 | { |
2456e855 | 2896 | ktime_t *to = NULL, timeout = KTIME_MAX; |
943df148 | 2897 | struct task_struct *tsk = current; |
943df148 | 2898 | sigset_t mask = *which; |
2b1ecc3d | 2899 | int sig, ret = 0; |
943df148 ON |
2900 | |
2901 | if (ts) { | |
2902 | if (!timespec_valid(ts)) | |
2903 | return -EINVAL; | |
2b1ecc3d TG |
2904 | timeout = timespec_to_ktime(*ts); |
2905 | to = &timeout; | |
943df148 ON |
2906 | } |
2907 | ||
2908 | /* | |
2909 | * Invert the set of allowed signals to get those we want to block. | |
2910 | */ | |
2911 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2912 | signotset(&mask); | |
2913 | ||
2914 | spin_lock_irq(&tsk->sighand->siglock); | |
2915 | sig = dequeue_signal(tsk, &mask, info); | |
2456e855 | 2916 | if (!sig && timeout) { |
943df148 ON |
2917 | /* |
2918 | * None ready, temporarily unblock those we're interested | |
2919 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
2920 | * they arrive. Unblocking is always fine, we can avoid |
2921 | * set_current_blocked(). | |
943df148 ON |
2922 | */ |
2923 | tsk->real_blocked = tsk->blocked; | |
2924 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
2925 | recalc_sigpending(); | |
2926 | spin_unlock_irq(&tsk->sighand->siglock); | |
2927 | ||
2b1ecc3d TG |
2928 | __set_current_state(TASK_INTERRUPTIBLE); |
2929 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, | |
2930 | HRTIMER_MODE_REL); | |
943df148 | 2931 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2932 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 2933 | sigemptyset(&tsk->real_blocked); |
b182801a | 2934 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
2935 | } |
2936 | spin_unlock_irq(&tsk->sighand->siglock); | |
2937 | ||
2938 | if (sig) | |
2939 | return sig; | |
2b1ecc3d | 2940 | return ret ? -EINTR : -EAGAIN; |
943df148 ON |
2941 | } |
2942 | ||
41c57892 RD |
2943 | /** |
2944 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
2945 | * in @uthese | |
2946 | * @uthese: queued signals to wait for | |
2947 | * @uinfo: if non-null, the signal's siginfo is returned here | |
2948 | * @uts: upper bound on process time suspension | |
2949 | * @sigsetsize: size of sigset_t type | |
2950 | */ | |
17da2bd9 HC |
2951 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
2952 | siginfo_t __user *, uinfo, const struct timespec __user *, uts, | |
2953 | size_t, sigsetsize) | |
1da177e4 | 2954 | { |
1da177e4 LT |
2955 | sigset_t these; |
2956 | struct timespec ts; | |
2957 | siginfo_t info; | |
943df148 | 2958 | int ret; |
1da177e4 LT |
2959 | |
2960 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2961 | if (sigsetsize != sizeof(sigset_t)) | |
2962 | return -EINVAL; | |
2963 | ||
2964 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2965 | return -EFAULT; | |
5aba085e | 2966 | |
1da177e4 LT |
2967 | if (uts) { |
2968 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2969 | return -EFAULT; | |
1da177e4 LT |
2970 | } |
2971 | ||
943df148 | 2972 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 2973 | |
943df148 ON |
2974 | if (ret > 0 && uinfo) { |
2975 | if (copy_siginfo_to_user(uinfo, &info)) | |
2976 | ret = -EFAULT; | |
1da177e4 LT |
2977 | } |
2978 | ||
2979 | return ret; | |
2980 | } | |
2981 | ||
1b3c872c AV |
2982 | #ifdef CONFIG_COMPAT |
2983 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese, | |
2984 | struct compat_siginfo __user *, uinfo, | |
2985 | struct compat_timespec __user *, uts, compat_size_t, sigsetsize) | |
2986 | { | |
1b3c872c AV |
2987 | sigset_t s; |
2988 | struct timespec t; | |
2989 | siginfo_t info; | |
2990 | long ret; | |
2991 | ||
2992 | if (sigsetsize != sizeof(sigset_t)) | |
2993 | return -EINVAL; | |
2994 | ||
3968cf62 | 2995 | if (get_compat_sigset(&s, uthese)) |
1b3c872c | 2996 | return -EFAULT; |
1b3c872c AV |
2997 | |
2998 | if (uts) { | |
2999 | if (compat_get_timespec(&t, uts)) | |
3000 | return -EFAULT; | |
3001 | } | |
3002 | ||
3003 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); | |
3004 | ||
3005 | if (ret > 0 && uinfo) { | |
3006 | if (copy_siginfo_to_user32(uinfo, &info)) | |
3007 | ret = -EFAULT; | |
3008 | } | |
3009 | ||
3010 | return ret; | |
3011 | } | |
3012 | #endif | |
3013 | ||
41c57892 RD |
3014 | /** |
3015 | * sys_kill - send a signal to a process | |
3016 | * @pid: the PID of the process | |
3017 | * @sig: signal to be sent | |
3018 | */ | |
17da2bd9 | 3019 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 LT |
3020 | { |
3021 | struct siginfo info; | |
3022 | ||
3023 | info.si_signo = sig; | |
3024 | info.si_errno = 0; | |
3025 | info.si_code = SI_USER; | |
b488893a | 3026 | info.si_pid = task_tgid_vnr(current); |
078de5f7 | 3027 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
3028 | |
3029 | return kill_something_info(sig, &info, pid); | |
3030 | } | |
3031 | ||
30b4ae8a TG |
3032 | static int |
3033 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info) | |
1da177e4 | 3034 | { |
1da177e4 | 3035 | struct task_struct *p; |
30b4ae8a | 3036 | int error = -ESRCH; |
1da177e4 | 3037 | |
3547ff3a | 3038 | rcu_read_lock(); |
228ebcbe | 3039 | p = find_task_by_vpid(pid); |
b488893a | 3040 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 3041 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
3042 | /* |
3043 | * The null signal is a permissions and process existence | |
3044 | * probe. No signal is actually delivered. | |
3045 | */ | |
4a30debf ON |
3046 | if (!error && sig) { |
3047 | error = do_send_sig_info(sig, info, p, false); | |
3048 | /* | |
3049 | * If lock_task_sighand() failed we pretend the task | |
3050 | * dies after receiving the signal. The window is tiny, | |
3051 | * and the signal is private anyway. | |
3052 | */ | |
3053 | if (unlikely(error == -ESRCH)) | |
3054 | error = 0; | |
1da177e4 LT |
3055 | } |
3056 | } | |
3547ff3a | 3057 | rcu_read_unlock(); |
6dd69f10 | 3058 | |
1da177e4 LT |
3059 | return error; |
3060 | } | |
3061 | ||
30b4ae8a TG |
3062 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
3063 | { | |
b9e146d8 | 3064 | struct siginfo info = {}; |
30b4ae8a TG |
3065 | |
3066 | info.si_signo = sig; | |
3067 | info.si_errno = 0; | |
3068 | info.si_code = SI_TKILL; | |
3069 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 3070 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
3071 | |
3072 | return do_send_specific(tgid, pid, sig, &info); | |
3073 | } | |
3074 | ||
6dd69f10 VL |
3075 | /** |
3076 | * sys_tgkill - send signal to one specific thread | |
3077 | * @tgid: the thread group ID of the thread | |
3078 | * @pid: the PID of the thread | |
3079 | * @sig: signal to be sent | |
3080 | * | |
72fd4a35 | 3081 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
3082 | * exists but it's not belonging to the target process anymore. This |
3083 | * method solves the problem of threads exiting and PIDs getting reused. | |
3084 | */ | |
a5f8fa9e | 3085 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
3086 | { |
3087 | /* This is only valid for single tasks */ | |
3088 | if (pid <= 0 || tgid <= 0) | |
3089 | return -EINVAL; | |
3090 | ||
3091 | return do_tkill(tgid, pid, sig); | |
3092 | } | |
3093 | ||
41c57892 RD |
3094 | /** |
3095 | * sys_tkill - send signal to one specific task | |
3096 | * @pid: the PID of the task | |
3097 | * @sig: signal to be sent | |
3098 | * | |
1da177e4 LT |
3099 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
3100 | */ | |
a5f8fa9e | 3101 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 3102 | { |
1da177e4 LT |
3103 | /* This is only valid for single tasks */ |
3104 | if (pid <= 0) | |
3105 | return -EINVAL; | |
3106 | ||
6dd69f10 | 3107 | return do_tkill(0, pid, sig); |
1da177e4 LT |
3108 | } |
3109 | ||
75907d4d AV |
3110 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) |
3111 | { | |
3112 | /* Not even root can pretend to send signals from the kernel. | |
3113 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
3114 | */ | |
66dd34ad | 3115 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
69828dce | 3116 | (task_pid_vnr(current) != pid)) |
75907d4d | 3117 | return -EPERM; |
69828dce | 3118 | |
75907d4d AV |
3119 | info->si_signo = sig; |
3120 | ||
3121 | /* POSIX.1b doesn't mention process groups. */ | |
3122 | return kill_proc_info(sig, info, pid); | |
3123 | } | |
3124 | ||
41c57892 RD |
3125 | /** |
3126 | * sys_rt_sigqueueinfo - send signal information to a signal | |
3127 | * @pid: the PID of the thread | |
3128 | * @sig: signal to be sent | |
3129 | * @uinfo: signal info to be sent | |
3130 | */ | |
a5f8fa9e HC |
3131 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
3132 | siginfo_t __user *, uinfo) | |
1da177e4 LT |
3133 | { |
3134 | siginfo_t info; | |
1da177e4 LT |
3135 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) |
3136 | return -EFAULT; | |
75907d4d AV |
3137 | return do_rt_sigqueueinfo(pid, sig, &info); |
3138 | } | |
1da177e4 | 3139 | |
75907d4d | 3140 | #ifdef CONFIG_COMPAT |
75907d4d AV |
3141 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
3142 | compat_pid_t, pid, | |
3143 | int, sig, | |
3144 | struct compat_siginfo __user *, uinfo) | |
3145 | { | |
3c00cb5e | 3146 | siginfo_t info = {}; |
75907d4d AV |
3147 | int ret = copy_siginfo_from_user32(&info, uinfo); |
3148 | if (unlikely(ret)) | |
3149 | return ret; | |
3150 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 3151 | } |
75907d4d | 3152 | #endif |
1da177e4 | 3153 | |
9aae8fc0 | 3154 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) |
62ab4505 TG |
3155 | { |
3156 | /* This is only valid for single tasks */ | |
3157 | if (pid <= 0 || tgid <= 0) | |
3158 | return -EINVAL; | |
3159 | ||
3160 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3161 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3162 | */ | |
69828dce VD |
3163 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3164 | (task_pid_vnr(current) != pid)) | |
62ab4505 | 3165 | return -EPERM; |
69828dce | 3166 | |
62ab4505 TG |
3167 | info->si_signo = sig; |
3168 | ||
3169 | return do_send_specific(tgid, pid, sig, info); | |
3170 | } | |
3171 | ||
3172 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3173 | siginfo_t __user *, uinfo) | |
3174 | { | |
3175 | siginfo_t info; | |
3176 | ||
3177 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
3178 | return -EFAULT; | |
3179 | ||
3180 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3181 | } | |
3182 | ||
9aae8fc0 AV |
3183 | #ifdef CONFIG_COMPAT |
3184 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3185 | compat_pid_t, tgid, | |
3186 | compat_pid_t, pid, | |
3187 | int, sig, | |
3188 | struct compat_siginfo __user *, uinfo) | |
3189 | { | |
3c00cb5e | 3190 | siginfo_t info = {}; |
9aae8fc0 AV |
3191 | |
3192 | if (copy_siginfo_from_user32(&info, uinfo)) | |
3193 | return -EFAULT; | |
3194 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); | |
3195 | } | |
3196 | #endif | |
3197 | ||
0341729b | 3198 | /* |
b4e74264 | 3199 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
0341729b | 3200 | */ |
b4e74264 | 3201 | void kernel_sigaction(int sig, __sighandler_t action) |
0341729b | 3202 | { |
ec5955b8 | 3203 | spin_lock_irq(¤t->sighand->siglock); |
b4e74264 ON |
3204 | current->sighand->action[sig - 1].sa.sa_handler = action; |
3205 | if (action == SIG_IGN) { | |
3206 | sigset_t mask; | |
0341729b | 3207 | |
b4e74264 ON |
3208 | sigemptyset(&mask); |
3209 | sigaddset(&mask, sig); | |
580d34e4 | 3210 | |
b4e74264 ON |
3211 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
3212 | flush_sigqueue_mask(&mask, ¤t->pending); | |
3213 | recalc_sigpending(); | |
3214 | } | |
0341729b ON |
3215 | spin_unlock_irq(¤t->sighand->siglock); |
3216 | } | |
b4e74264 | 3217 | EXPORT_SYMBOL(kernel_sigaction); |
0341729b | 3218 | |
68463510 DS |
3219 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
3220 | struct k_sigaction *oact) | |
3221 | { | |
3222 | } | |
3223 | ||
88531f72 | 3224 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3225 | { |
afe2b038 | 3226 | struct task_struct *p = current, *t; |
1da177e4 | 3227 | struct k_sigaction *k; |
71fabd5e | 3228 | sigset_t mask; |
1da177e4 | 3229 | |
7ed20e1a | 3230 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3231 | return -EINVAL; |
3232 | ||
afe2b038 | 3233 | k = &p->sighand->action[sig-1]; |
1da177e4 | 3234 | |
afe2b038 | 3235 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
3236 | if (oact) |
3237 | *oact = *k; | |
3238 | ||
68463510 DS |
3239 | sigaction_compat_abi(act, oact); |
3240 | ||
1da177e4 | 3241 | if (act) { |
9ac95f2f ON |
3242 | sigdelsetmask(&act->sa.sa_mask, |
3243 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3244 | *k = *act; |
1da177e4 LT |
3245 | /* |
3246 | * POSIX 3.3.1.3: | |
3247 | * "Setting a signal action to SIG_IGN for a signal that is | |
3248 | * pending shall cause the pending signal to be discarded, | |
3249 | * whether or not it is blocked." | |
3250 | * | |
3251 | * "Setting a signal action to SIG_DFL for a signal that is | |
3252 | * pending and whose default action is to ignore the signal | |
3253 | * (for example, SIGCHLD), shall cause the pending signal to | |
3254 | * be discarded, whether or not it is blocked" | |
3255 | */ | |
afe2b038 | 3256 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
71fabd5e GA |
3257 | sigemptyset(&mask); |
3258 | sigaddset(&mask, sig); | |
afe2b038 ON |
3259 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
3260 | for_each_thread(p, t) | |
c09c1441 | 3261 | flush_sigqueue_mask(&mask, &t->pending); |
1da177e4 | 3262 | } |
1da177e4 LT |
3263 | } |
3264 | ||
afe2b038 | 3265 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
3266 | return 0; |
3267 | } | |
3268 | ||
c09c1441 | 3269 | static int |
50ff5fd2 WD |
3270 | do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, |
3271 | size_t min_ss_size) | |
1da177e4 | 3272 | { |
bcfe8ad8 | 3273 | struct task_struct *t = current; |
1da177e4 | 3274 | |
bcfe8ad8 AV |
3275 | if (oss) { |
3276 | memset(oss, 0, sizeof(stack_t)); | |
3277 | oss->ss_sp = (void __user *) t->sas_ss_sp; | |
3278 | oss->ss_size = t->sas_ss_size; | |
3279 | oss->ss_flags = sas_ss_flags(sp) | | |
3280 | (current->sas_ss_flags & SS_FLAG_BITS); | |
3281 | } | |
1da177e4 | 3282 | |
bcfe8ad8 AV |
3283 | if (ss) { |
3284 | void __user *ss_sp = ss->ss_sp; | |
3285 | size_t ss_size = ss->ss_size; | |
3286 | unsigned ss_flags = ss->ss_flags; | |
407bc16a | 3287 | int ss_mode; |
1da177e4 | 3288 | |
bcfe8ad8 AV |
3289 | if (unlikely(on_sig_stack(sp))) |
3290 | return -EPERM; | |
1da177e4 | 3291 | |
407bc16a | 3292 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
bcfe8ad8 AV |
3293 | if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
3294 | ss_mode != 0)) | |
3295 | return -EINVAL; | |
1da177e4 | 3296 | |
407bc16a | 3297 | if (ss_mode == SS_DISABLE) { |
1da177e4 LT |
3298 | ss_size = 0; |
3299 | ss_sp = NULL; | |
3300 | } else { | |
50ff5fd2 | 3301 | if (unlikely(ss_size < min_ss_size)) |
bcfe8ad8 | 3302 | return -ENOMEM; |
1da177e4 LT |
3303 | } |
3304 | ||
bcfe8ad8 AV |
3305 | t->sas_ss_sp = (unsigned long) ss_sp; |
3306 | t->sas_ss_size = ss_size; | |
3307 | t->sas_ss_flags = ss_flags; | |
1da177e4 | 3308 | } |
bcfe8ad8 | 3309 | return 0; |
1da177e4 | 3310 | } |
bcfe8ad8 | 3311 | |
6bf9adfc AV |
3312 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3313 | { | |
bcfe8ad8 AV |
3314 | stack_t new, old; |
3315 | int err; | |
3316 | if (uss && copy_from_user(&new, uss, sizeof(stack_t))) | |
3317 | return -EFAULT; | |
3318 | err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL, | |
50ff5fd2 WD |
3319 | current_user_stack_pointer(), |
3320 | MINSIGSTKSZ); | |
bcfe8ad8 AV |
3321 | if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t))) |
3322 | err = -EFAULT; | |
3323 | return err; | |
6bf9adfc | 3324 | } |
1da177e4 | 3325 | |
5c49574f AV |
3326 | int restore_altstack(const stack_t __user *uss) |
3327 | { | |
bcfe8ad8 AV |
3328 | stack_t new; |
3329 | if (copy_from_user(&new, uss, sizeof(stack_t))) | |
3330 | return -EFAULT; | |
50ff5fd2 WD |
3331 | (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(), |
3332 | MINSIGSTKSZ); | |
5c49574f | 3333 | /* squash all but EFAULT for now */ |
bcfe8ad8 | 3334 | return 0; |
5c49574f AV |
3335 | } |
3336 | ||
c40702c4 AV |
3337 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3338 | { | |
3339 | struct task_struct *t = current; | |
2a742138 SS |
3340 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
3341 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3342 | __put_user(t->sas_ss_size, &uss->ss_size); |
2a742138 SS |
3343 | if (err) |
3344 | return err; | |
3345 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3346 | sas_ss_reset(t); | |
3347 | return 0; | |
c40702c4 AV |
3348 | } |
3349 | ||
90268439 | 3350 | #ifdef CONFIG_COMPAT |
90228fc1 AV |
3351 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
3352 | const compat_stack_t __user *, uss_ptr, | |
3353 | compat_stack_t __user *, uoss_ptr) | |
90268439 AV |
3354 | { |
3355 | stack_t uss, uoss; | |
3356 | int ret; | |
90268439 AV |
3357 | |
3358 | if (uss_ptr) { | |
3359 | compat_stack_t uss32; | |
90268439 AV |
3360 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) |
3361 | return -EFAULT; | |
3362 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
3363 | uss.ss_flags = uss32.ss_flags; | |
3364 | uss.ss_size = uss32.ss_size; | |
3365 | } | |
bcfe8ad8 | 3366 | ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, |
50ff5fd2 WD |
3367 | compat_user_stack_pointer(), |
3368 | COMPAT_MINSIGSTKSZ); | |
90268439 | 3369 | if (ret >= 0 && uoss_ptr) { |
bcfe8ad8 AV |
3370 | compat_stack_t old; |
3371 | memset(&old, 0, sizeof(old)); | |
3372 | old.ss_sp = ptr_to_compat(uoss.ss_sp); | |
3373 | old.ss_flags = uoss.ss_flags; | |
3374 | old.ss_size = uoss.ss_size; | |
3375 | if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t))) | |
90268439 AV |
3376 | ret = -EFAULT; |
3377 | } | |
3378 | return ret; | |
3379 | } | |
3380 | ||
3381 | int compat_restore_altstack(const compat_stack_t __user *uss) | |
3382 | { | |
3383 | int err = compat_sys_sigaltstack(uss, NULL); | |
3384 | /* squash all but -EFAULT for now */ | |
3385 | return err == -EFAULT ? err : 0; | |
3386 | } | |
c40702c4 AV |
3387 | |
3388 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
3389 | { | |
441398d3 | 3390 | int err; |
c40702c4 | 3391 | struct task_struct *t = current; |
441398d3 SS |
3392 | err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
3393 | &uss->ss_sp) | | |
3394 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3395 | __put_user(t->sas_ss_size, &uss->ss_size); |
441398d3 SS |
3396 | if (err) |
3397 | return err; | |
3398 | if (t->sas_ss_flags & SS_AUTODISARM) | |
3399 | sas_ss_reset(t); | |
3400 | return 0; | |
c40702c4 | 3401 | } |
90268439 | 3402 | #endif |
1da177e4 LT |
3403 | |
3404 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
3405 | ||
41c57892 RD |
3406 | /** |
3407 | * sys_sigpending - examine pending signals | |
3408 | * @set: where mask of pending signal is returned | |
3409 | */ | |
b290ebe2 | 3410 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) |
1da177e4 | 3411 | { |
fe9c1db2 | 3412 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); |
1da177e4 LT |
3413 | } |
3414 | ||
8f13621a AV |
3415 | #ifdef CONFIG_COMPAT |
3416 | COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) | |
3417 | { | |
3418 | sigset_t set; | |
176826af | 3419 | int err = do_sigpending(&set); |
fbb77611 DL |
3420 | if (!err) |
3421 | err = put_user(set.sig[0], set32); | |
8f13621a AV |
3422 | return err; |
3423 | } | |
3424 | #endif | |
3425 | ||
1da177e4 LT |
3426 | #endif |
3427 | ||
3428 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
3429 | /** |
3430 | * sys_sigprocmask - examine and change blocked signals | |
3431 | * @how: whether to add, remove, or set signals | |
b013c399 | 3432 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
3433 | * @oset: previous value of signal mask if non-null |
3434 | * | |
5aba085e RD |
3435 | * Some platforms have their own version with special arguments; |
3436 | * others support only sys_rt_sigprocmask. | |
3437 | */ | |
1da177e4 | 3438 | |
b013c399 | 3439 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 3440 | old_sigset_t __user *, oset) |
1da177e4 | 3441 | { |
1da177e4 | 3442 | old_sigset_t old_set, new_set; |
2e4f7c77 | 3443 | sigset_t new_blocked; |
1da177e4 | 3444 | |
b013c399 | 3445 | old_set = current->blocked.sig[0]; |
1da177e4 | 3446 | |
b013c399 ON |
3447 | if (nset) { |
3448 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
3449 | return -EFAULT; | |
1da177e4 | 3450 | |
2e4f7c77 | 3451 | new_blocked = current->blocked; |
1da177e4 | 3452 | |
1da177e4 | 3453 | switch (how) { |
1da177e4 | 3454 | case SIG_BLOCK: |
2e4f7c77 | 3455 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
3456 | break; |
3457 | case SIG_UNBLOCK: | |
2e4f7c77 | 3458 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
3459 | break; |
3460 | case SIG_SETMASK: | |
2e4f7c77 | 3461 | new_blocked.sig[0] = new_set; |
1da177e4 | 3462 | break; |
2e4f7c77 ON |
3463 | default: |
3464 | return -EINVAL; | |
1da177e4 LT |
3465 | } |
3466 | ||
0c4a8423 | 3467 | set_current_blocked(&new_blocked); |
b013c399 ON |
3468 | } |
3469 | ||
3470 | if (oset) { | |
1da177e4 | 3471 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 3472 | return -EFAULT; |
1da177e4 | 3473 | } |
b013c399 ON |
3474 | |
3475 | return 0; | |
1da177e4 LT |
3476 | } |
3477 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
3478 | ||
eaca6eae | 3479 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
3480 | /** |
3481 | * sys_rt_sigaction - alter an action taken by a process | |
3482 | * @sig: signal to be sent | |
f9fa0bc1 RD |
3483 | * @act: new sigaction |
3484 | * @oact: used to save the previous sigaction | |
41c57892 RD |
3485 | * @sigsetsize: size of sigset_t type |
3486 | */ | |
d4e82042 HC |
3487 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3488 | const struct sigaction __user *, act, | |
3489 | struct sigaction __user *, oact, | |
3490 | size_t, sigsetsize) | |
1da177e4 LT |
3491 | { |
3492 | struct k_sigaction new_sa, old_sa; | |
3493 | int ret = -EINVAL; | |
3494 | ||
3495 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3496 | if (sigsetsize != sizeof(sigset_t)) | |
3497 | goto out; | |
3498 | ||
3499 | if (act) { | |
3500 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
3501 | return -EFAULT; | |
3502 | } | |
3503 | ||
3504 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
3505 | ||
3506 | if (!ret && oact) { | |
3507 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
3508 | return -EFAULT; | |
3509 | } | |
3510 | out: | |
3511 | return ret; | |
3512 | } | |
08d32fe5 | 3513 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
3514 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
3515 | const struct compat_sigaction __user *, act, | |
3516 | struct compat_sigaction __user *, oact, | |
3517 | compat_size_t, sigsetsize) | |
3518 | { | |
3519 | struct k_sigaction new_ka, old_ka; | |
08d32fe5 AV |
3520 | #ifdef __ARCH_HAS_SA_RESTORER |
3521 | compat_uptr_t restorer; | |
3522 | #endif | |
3523 | int ret; | |
3524 | ||
3525 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3526 | if (sigsetsize != sizeof(compat_sigset_t)) | |
3527 | return -EINVAL; | |
3528 | ||
3529 | if (act) { | |
3530 | compat_uptr_t handler; | |
3531 | ret = get_user(handler, &act->sa_handler); | |
3532 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3533 | #ifdef __ARCH_HAS_SA_RESTORER | |
3534 | ret |= get_user(restorer, &act->sa_restorer); | |
3535 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3536 | #endif | |
3968cf62 | 3537 | ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask); |
3ddc5b46 | 3538 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
3539 | if (ret) |
3540 | return -EFAULT; | |
08d32fe5 AV |
3541 | } |
3542 | ||
3543 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3544 | if (!ret && oact) { | |
08d32fe5 AV |
3545 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), |
3546 | &oact->sa_handler); | |
f454322e DL |
3547 | ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, |
3548 | sizeof(oact->sa_mask)); | |
3ddc5b46 | 3549 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
3550 | #ifdef __ARCH_HAS_SA_RESTORER |
3551 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3552 | &oact->sa_restorer); | |
3553 | #endif | |
3554 | } | |
3555 | return ret; | |
3556 | } | |
3557 | #endif | |
eaca6eae | 3558 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 3559 | |
495dfbf7 AV |
3560 | #ifdef CONFIG_OLD_SIGACTION |
3561 | SYSCALL_DEFINE3(sigaction, int, sig, | |
3562 | const struct old_sigaction __user *, act, | |
3563 | struct old_sigaction __user *, oact) | |
3564 | { | |
3565 | struct k_sigaction new_ka, old_ka; | |
3566 | int ret; | |
3567 | ||
3568 | if (act) { | |
3569 | old_sigset_t mask; | |
3570 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3571 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
3572 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
3573 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3574 | __get_user(mask, &act->sa_mask)) | |
3575 | return -EFAULT; | |
3576 | #ifdef __ARCH_HAS_KA_RESTORER | |
3577 | new_ka.ka_restorer = NULL; | |
3578 | #endif | |
3579 | siginitset(&new_ka.sa.sa_mask, mask); | |
3580 | } | |
3581 | ||
3582 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3583 | ||
3584 | if (!ret && oact) { | |
3585 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3586 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
3587 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
3588 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3589 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3590 | return -EFAULT; | |
3591 | } | |
3592 | ||
3593 | return ret; | |
3594 | } | |
3595 | #endif | |
3596 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
3597 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
3598 | const struct compat_old_sigaction __user *, act, | |
3599 | struct compat_old_sigaction __user *, oact) | |
3600 | { | |
3601 | struct k_sigaction new_ka, old_ka; | |
3602 | int ret; | |
3603 | compat_old_sigset_t mask; | |
3604 | compat_uptr_t handler, restorer; | |
3605 | ||
3606 | if (act) { | |
3607 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
3608 | __get_user(handler, &act->sa_handler) || | |
3609 | __get_user(restorer, &act->sa_restorer) || | |
3610 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
3611 | __get_user(mask, &act->sa_mask)) | |
3612 | return -EFAULT; | |
3613 | ||
3614 | #ifdef __ARCH_HAS_KA_RESTORER | |
3615 | new_ka.ka_restorer = NULL; | |
3616 | #endif | |
3617 | new_ka.sa.sa_handler = compat_ptr(handler); | |
3618 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
3619 | siginitset(&new_ka.sa.sa_mask, mask); | |
3620 | } | |
3621 | ||
3622 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
3623 | ||
3624 | if (!ret && oact) { | |
3625 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
3626 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), | |
3627 | &oact->sa_handler) || | |
3628 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
3629 | &oact->sa_restorer) || | |
3630 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
3631 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
3632 | return -EFAULT; | |
3633 | } | |
3634 | return ret; | |
3635 | } | |
3636 | #endif | |
1da177e4 | 3637 | |
f6187769 | 3638 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
3639 | |
3640 | /* | |
3641 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
3642 | */ | |
a5f8fa9e | 3643 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
3644 | { |
3645 | /* SMP safe */ | |
3646 | return current->blocked.sig[0]; | |
3647 | } | |
3648 | ||
a5f8fa9e | 3649 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 3650 | { |
c1095c6d ON |
3651 | int old = current->blocked.sig[0]; |
3652 | sigset_t newset; | |
1da177e4 | 3653 | |
5ba53ff6 | 3654 | siginitset(&newset, newmask); |
c1095c6d | 3655 | set_current_blocked(&newset); |
1da177e4 LT |
3656 | |
3657 | return old; | |
3658 | } | |
f6187769 | 3659 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
3660 | |
3661 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
3662 | /* | |
3663 | * For backwards compatibility. Functionality superseded by sigaction. | |
3664 | */ | |
a5f8fa9e | 3665 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
3666 | { |
3667 | struct k_sigaction new_sa, old_sa; | |
3668 | int ret; | |
3669 | ||
3670 | new_sa.sa.sa_handler = handler; | |
3671 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 3672 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
3673 | |
3674 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
3675 | ||
3676 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
3677 | } | |
3678 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
3679 | ||
3680 | #ifdef __ARCH_WANT_SYS_PAUSE | |
3681 | ||
a5f8fa9e | 3682 | SYSCALL_DEFINE0(pause) |
1da177e4 | 3683 | { |
d92fcf05 | 3684 | while (!signal_pending(current)) { |
1df01355 | 3685 | __set_current_state(TASK_INTERRUPTIBLE); |
d92fcf05 ON |
3686 | schedule(); |
3687 | } | |
1da177e4 LT |
3688 | return -ERESTARTNOHAND; |
3689 | } | |
3690 | ||
3691 | #endif | |
3692 | ||
9d8a7652 | 3693 | static int sigsuspend(sigset_t *set) |
68f3f16d | 3694 | { |
68f3f16d AV |
3695 | current->saved_sigmask = current->blocked; |
3696 | set_current_blocked(set); | |
3697 | ||
823dd322 SL |
3698 | while (!signal_pending(current)) { |
3699 | __set_current_state(TASK_INTERRUPTIBLE); | |
3700 | schedule(); | |
3701 | } | |
68f3f16d AV |
3702 | set_restore_sigmask(); |
3703 | return -ERESTARTNOHAND; | |
3704 | } | |
68f3f16d | 3705 | |
41c57892 RD |
3706 | /** |
3707 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
3708 | * @unewset value until a signal is received | |
3709 | * @unewset: new signal mask value | |
3710 | * @sigsetsize: size of sigset_t type | |
3711 | */ | |
d4e82042 | 3712 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
3713 | { |
3714 | sigset_t newset; | |
3715 | ||
3716 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3717 | if (sigsetsize != sizeof(sigset_t)) | |
3718 | return -EINVAL; | |
3719 | ||
3720 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
3721 | return -EFAULT; | |
68f3f16d | 3722 | return sigsuspend(&newset); |
150256d8 | 3723 | } |
ad4b65a4 AV |
3724 | |
3725 | #ifdef CONFIG_COMPAT | |
3726 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
3727 | { | |
ad4b65a4 | 3728 | sigset_t newset; |
ad4b65a4 AV |
3729 | |
3730 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3731 | if (sigsetsize != sizeof(sigset_t)) | |
3732 | return -EINVAL; | |
3733 | ||
3968cf62 | 3734 | if (get_compat_sigset(&newset, unewset)) |
ad4b65a4 | 3735 | return -EFAULT; |
ad4b65a4 | 3736 | return sigsuspend(&newset); |
ad4b65a4 AV |
3737 | } |
3738 | #endif | |
150256d8 | 3739 | |
0a0e8cdf AV |
3740 | #ifdef CONFIG_OLD_SIGSUSPEND |
3741 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
3742 | { | |
3743 | sigset_t blocked; | |
3744 | siginitset(&blocked, mask); | |
3745 | return sigsuspend(&blocked); | |
3746 | } | |
3747 | #endif | |
3748 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
3749 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
3750 | { | |
3751 | sigset_t blocked; | |
3752 | siginitset(&blocked, mask); | |
3753 | return sigsuspend(&blocked); | |
3754 | } | |
3755 | #endif | |
150256d8 | 3756 | |
52f5684c | 3757 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
3758 | { |
3759 | return NULL; | |
3760 | } | |
3761 | ||
1da177e4 LT |
3762 | void __init signals_init(void) |
3763 | { | |
41b27154 HD |
3764 | /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */ |
3765 | BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE | |
3766 | != offsetof(struct siginfo, _sifields._pad)); | |
3767 | ||
0a31bd5f | 3768 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 3769 | } |
67fc4e0c JW |
3770 | |
3771 | #ifdef CONFIG_KGDB_KDB | |
3772 | #include <linux/kdb.h> | |
3773 | /* | |
3774 | * kdb_send_sig_info - Allows kdb to send signals without exposing | |
3775 | * signal internals. This function checks if the required locks are | |
3776 | * available before calling the main signal code, to avoid kdb | |
3777 | * deadlocks. | |
3778 | */ | |
3779 | void | |
3780 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info) | |
3781 | { | |
3782 | static struct task_struct *kdb_prev_t; | |
3783 | int sig, new_t; | |
3784 | if (!spin_trylock(&t->sighand->siglock)) { | |
3785 | kdb_printf("Can't do kill command now.\n" | |
3786 | "The sigmask lock is held somewhere else in " | |
3787 | "kernel, try again later\n"); | |
3788 | return; | |
3789 | } | |
3790 | spin_unlock(&t->sighand->siglock); | |
3791 | new_t = kdb_prev_t != t; | |
3792 | kdb_prev_t = t; | |
3793 | if (t->state != TASK_RUNNING && new_t) { | |
3794 | kdb_printf("Process is not RUNNING, sending a signal from " | |
3795 | "kdb risks deadlock\n" | |
3796 | "on the run queue locks. " | |
3797 | "The signal has _not_ been sent.\n" | |
3798 | "Reissue the kill command if you want to risk " | |
3799 | "the deadlock.\n"); | |
3800 | return; | |
3801 | } | |
3802 | sig = info->si_signo; | |
3803 | if (send_sig_info(sig, info, t)) | |
3804 | kdb_printf("Fail to deliver Signal %d to process %d.\n", | |
3805 | sig, t->pid); | |
3806 | else | |
3807 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
3808 | } | |
3809 | #endif /* CONFIG_KGDB_KDB */ |