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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> |
3eb39f47 | 22 | #include <linux/file.h> |
1da177e4 | 23 | #include <linux/fs.h> |
3eb39f47 | 24 | #include <linux/proc_fs.h> |
1da177e4 LT |
25 | #include <linux/tty.h> |
26 | #include <linux/binfmts.h> | |
179899fd | 27 | #include <linux/coredump.h> |
1da177e4 LT |
28 | #include <linux/security.h> |
29 | #include <linux/syscalls.h> | |
30 | #include <linux/ptrace.h> | |
7ed20e1a | 31 | #include <linux/signal.h> |
fba2afaa | 32 | #include <linux/signalfd.h> |
f84d49b2 | 33 | #include <linux/ratelimit.h> |
35de254d | 34 | #include <linux/tracehook.h> |
c59ede7b | 35 | #include <linux/capability.h> |
7dfb7103 | 36 | #include <linux/freezer.h> |
84d73786 SB |
37 | #include <linux/pid_namespace.h> |
38 | #include <linux/nsproxy.h> | |
6b550f94 | 39 | #include <linux/user_namespace.h> |
0326f5a9 | 40 | #include <linux/uprobes.h> |
90268439 | 41 | #include <linux/compat.h> |
2b5faa4c | 42 | #include <linux/cn_proc.h> |
52f5684c | 43 | #include <linux/compiler.h> |
31ea70e0 | 44 | #include <linux/posix-timers.h> |
43347d56 | 45 | #include <linux/livepatch.h> |
76f969e8 | 46 | #include <linux/cgroup.h> |
52f5684c | 47 | |
d1eb650f MH |
48 | #define CREATE_TRACE_POINTS |
49 | #include <trace/events/signal.h> | |
84d73786 | 50 | |
1da177e4 | 51 | #include <asm/param.h> |
7c0f6ba6 | 52 | #include <linux/uaccess.h> |
1da177e4 LT |
53 | #include <asm/unistd.h> |
54 | #include <asm/siginfo.h> | |
d550bbd4 | 55 | #include <asm/cacheflush.h> |
e1396065 | 56 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
57 | |
58 | /* | |
59 | * SLAB caches for signal bits. | |
60 | */ | |
61 | ||
e18b890b | 62 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 63 | |
f84d49b2 NO |
64 | int print_fatal_signals __read_mostly; |
65 | ||
35de254d | 66 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 67 | { |
35de254d RM |
68 | return t->sighand->action[sig - 1].sa.sa_handler; |
69 | } | |
93585eea | 70 | |
e4a8b4ef | 71 | static inline bool sig_handler_ignored(void __user *handler, int sig) |
35de254d | 72 | { |
93585eea | 73 | /* Is it explicitly or implicitly ignored? */ |
93585eea | 74 | return handler == SIG_IGN || |
e4a8b4ef | 75 | (handler == SIG_DFL && sig_kernel_ignore(sig)); |
93585eea | 76 | } |
1da177e4 | 77 | |
41aaa481 | 78 | static bool sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 79 | { |
35de254d | 80 | void __user *handler; |
1da177e4 | 81 | |
f008faff ON |
82 | handler = sig_handler(t, sig); |
83 | ||
86989c41 EB |
84 | /* SIGKILL and SIGSTOP may not be sent to the global init */ |
85 | if (unlikely(is_global_init(t) && sig_kernel_only(sig))) | |
86 | return true; | |
87 | ||
f008faff | 88 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && |
ac253850 | 89 | handler == SIG_DFL && !(force && sig_kernel_only(sig))) |
41aaa481 | 90 | return true; |
f008faff ON |
91 | |
92 | return sig_handler_ignored(handler, sig); | |
93 | } | |
94 | ||
6a0cdcd7 | 95 | static bool sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 96 | { |
1da177e4 LT |
97 | /* |
98 | * Blocked signals are never ignored, since the | |
99 | * signal handler may change by the time it is | |
100 | * unblocked. | |
101 | */ | |
325d22df | 102 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
6a0cdcd7 | 103 | return false; |
1da177e4 | 104 | |
35de254d | 105 | /* |
628c1bcb ON |
106 | * Tracers may want to know about even ignored signal unless it |
107 | * is SIGKILL which can't be reported anyway but can be ignored | |
108 | * by SIGNAL_UNKILLABLE task. | |
35de254d | 109 | */ |
628c1bcb | 110 | if (t->ptrace && sig != SIGKILL) |
6a0cdcd7 | 111 | return false; |
628c1bcb ON |
112 | |
113 | return sig_task_ignored(t, sig, force); | |
1da177e4 LT |
114 | } |
115 | ||
116 | /* | |
117 | * Re-calculate pending state from the set of locally pending | |
118 | * signals, globally pending signals, and blocked signals. | |
119 | */ | |
938696a8 | 120 | static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked) |
1da177e4 LT |
121 | { |
122 | unsigned long ready; | |
123 | long i; | |
124 | ||
125 | switch (_NSIG_WORDS) { | |
126 | default: | |
127 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
128 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
129 | break; | |
130 | ||
131 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
132 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
133 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
134 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
135 | break; | |
136 | ||
137 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
138 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
139 | break; | |
140 | ||
141 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
142 | } | |
143 | return ready != 0; | |
144 | } | |
145 | ||
146 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
147 | ||
09ae854e | 148 | static bool recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 149 | { |
76f969e8 | 150 | if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) || |
1da177e4 | 151 | PENDING(&t->pending, &t->blocked) || |
76f969e8 RG |
152 | PENDING(&t->signal->shared_pending, &t->blocked) || |
153 | cgroup_task_frozen(t)) { | |
1da177e4 | 154 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
09ae854e | 155 | return true; |
7bb44ade | 156 | } |
09ae854e | 157 | |
b74d0deb RM |
158 | /* |
159 | * We must never clear the flag in another thread, or in current | |
160 | * when it's possible the current syscall is returning -ERESTART*. | |
161 | * So we don't clear it here, and only callers who know they should do. | |
162 | */ | |
09ae854e | 163 | return false; |
7bb44ade RM |
164 | } |
165 | ||
166 | /* | |
167 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
168 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
169 | */ | |
170 | void recalc_sigpending_and_wake(struct task_struct *t) | |
171 | { | |
172 | if (recalc_sigpending_tsk(t)) | |
173 | signal_wake_up(t, 0); | |
1da177e4 LT |
174 | } |
175 | ||
176 | void recalc_sigpending(void) | |
177 | { | |
43347d56 MB |
178 | if (!recalc_sigpending_tsk(current) && !freezing(current) && |
179 | !klp_patch_pending(current)) | |
b74d0deb RM |
180 | clear_thread_flag(TIF_SIGPENDING); |
181 | ||
1da177e4 | 182 | } |
fb50f5a4 | 183 | EXPORT_SYMBOL(recalc_sigpending); |
1da177e4 | 184 | |
088fe47c EB |
185 | void calculate_sigpending(void) |
186 | { | |
187 | /* Have any signals or users of TIF_SIGPENDING been delayed | |
188 | * until after fork? | |
189 | */ | |
190 | spin_lock_irq(¤t->sighand->siglock); | |
191 | set_tsk_thread_flag(current, TIF_SIGPENDING); | |
192 | recalc_sigpending(); | |
193 | spin_unlock_irq(¤t->sighand->siglock); | |
194 | } | |
195 | ||
1da177e4 LT |
196 | /* Given the mask, find the first available signal that should be serviced. */ |
197 | ||
a27341cd LT |
198 | #define SYNCHRONOUS_MASK \ |
199 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 200 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 201 | |
fba2afaa | 202 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
203 | { |
204 | unsigned long i, *s, *m, x; | |
205 | int sig = 0; | |
f84d49b2 | 206 | |
1da177e4 LT |
207 | s = pending->signal.sig; |
208 | m = mask->sig; | |
a27341cd LT |
209 | |
210 | /* | |
211 | * Handle the first word specially: it contains the | |
212 | * synchronous signals that need to be dequeued first. | |
213 | */ | |
214 | x = *s &~ *m; | |
215 | if (x) { | |
216 | if (x & SYNCHRONOUS_MASK) | |
217 | x &= SYNCHRONOUS_MASK; | |
218 | sig = ffz(~x) + 1; | |
219 | return sig; | |
220 | } | |
221 | ||
1da177e4 LT |
222 | switch (_NSIG_WORDS) { |
223 | default: | |
a27341cd LT |
224 | for (i = 1; i < _NSIG_WORDS; ++i) { |
225 | x = *++s &~ *++m; | |
226 | if (!x) | |
227 | continue; | |
228 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
229 | break; | |
230 | } | |
1da177e4 LT |
231 | break; |
232 | ||
a27341cd LT |
233 | case 2: |
234 | x = s[1] &~ m[1]; | |
235 | if (!x) | |
1da177e4 | 236 | break; |
a27341cd | 237 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
238 | break; |
239 | ||
a27341cd LT |
240 | case 1: |
241 | /* Nothing to do */ | |
1da177e4 LT |
242 | break; |
243 | } | |
f84d49b2 | 244 | |
1da177e4 LT |
245 | return sig; |
246 | } | |
247 | ||
f84d49b2 NO |
248 | static inline void print_dropped_signal(int sig) |
249 | { | |
250 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
251 | ||
252 | if (!print_fatal_signals) | |
253 | return; | |
254 | ||
255 | if (!__ratelimit(&ratelimit_state)) | |
256 | return; | |
257 | ||
747800ef | 258 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
f84d49b2 NO |
259 | current->comm, current->pid, sig); |
260 | } | |
261 | ||
d79fdd6d | 262 | /** |
7dd3db54 | 263 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 264 | * @task: target task |
7dd3db54 | 265 | * @mask: pending bits to set |
d79fdd6d | 266 | * |
7dd3db54 TH |
267 | * Clear @mask from @task->jobctl. @mask must be subset of |
268 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
269 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
270 | * cleared. If @task is already being killed or exiting, this function | |
271 | * becomes noop. | |
272 | * | |
273 | * CONTEXT: | |
274 | * Must be called with @task->sighand->siglock held. | |
275 | * | |
276 | * RETURNS: | |
277 | * %true if @mask is set, %false if made noop because @task was dying. | |
278 | */ | |
b76808e6 | 279 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
7dd3db54 TH |
280 | { |
281 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
282 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
283 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
284 | ||
285 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) | |
286 | return false; | |
287 | ||
288 | if (mask & JOBCTL_STOP_SIGMASK) | |
289 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
290 | ||
291 | task->jobctl |= mask; | |
292 | return true; | |
293 | } | |
294 | ||
d79fdd6d | 295 | /** |
a8f072c1 | 296 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
297 | * @task: target task |
298 | * | |
a8f072c1 TH |
299 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
300 | * Clear it and wake up the ptracer. Note that we don't need any further | |
301 | * locking. @task->siglock guarantees that @task->parent points to the | |
302 | * ptracer. | |
d79fdd6d TH |
303 | * |
304 | * CONTEXT: | |
305 | * Must be called with @task->sighand->siglock held. | |
306 | */ | |
73ddff2b | 307 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 308 | { |
a8f072c1 TH |
309 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
310 | task->jobctl &= ~JOBCTL_TRAPPING; | |
650226bd | 311 | smp_mb(); /* advised by wake_up_bit() */ |
62c124ff | 312 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
313 | } |
314 | } | |
315 | ||
e5c1902e | 316 | /** |
3759a0d9 | 317 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 318 | * @task: target task |
3759a0d9 | 319 | * @mask: pending bits to clear |
e5c1902e | 320 | * |
3759a0d9 TH |
321 | * Clear @mask from @task->jobctl. @mask must be subset of |
322 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
323 | * STOP bits are cleared together. | |
e5c1902e | 324 | * |
6dfca329 TH |
325 | * If clearing of @mask leaves no stop or trap pending, this function calls |
326 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
327 | * |
328 | * CONTEXT: | |
329 | * Must be called with @task->sighand->siglock held. | |
330 | */ | |
b76808e6 | 331 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
e5c1902e | 332 | { |
3759a0d9 TH |
333 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
334 | ||
335 | if (mask & JOBCTL_STOP_PENDING) | |
336 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
337 | ||
338 | task->jobctl &= ~mask; | |
6dfca329 TH |
339 | |
340 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
341 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
342 | } |
343 | ||
344 | /** | |
345 | * task_participate_group_stop - participate in a group stop | |
346 | * @task: task participating in a group stop | |
347 | * | |
a8f072c1 | 348 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 349 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 350 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
39efa3ef | 351 | * stop, the appropriate %SIGNAL_* flags are set. |
e5c1902e TH |
352 | * |
353 | * CONTEXT: | |
354 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
355 | * |
356 | * RETURNS: | |
357 | * %true if group stop completion should be notified to the parent, %false | |
358 | * otherwise. | |
e5c1902e TH |
359 | */ |
360 | static bool task_participate_group_stop(struct task_struct *task) | |
361 | { | |
362 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 363 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 364 | |
a8f072c1 | 365 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 366 | |
3759a0d9 | 367 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
368 | |
369 | if (!consume) | |
370 | return false; | |
371 | ||
372 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
373 | sig->group_stop_count--; | |
374 | ||
244056f9 TH |
375 | /* |
376 | * Tell the caller to notify completion iff we are entering into a | |
377 | * fresh group stop. Read comment in do_signal_stop() for details. | |
378 | */ | |
379 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
2d39b3cd | 380 | signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
e5c1902e TH |
381 | return true; |
382 | } | |
383 | return false; | |
384 | } | |
385 | ||
924de3b8 EB |
386 | void task_join_group_stop(struct task_struct *task) |
387 | { | |
388 | /* Have the new thread join an on-going signal group stop */ | |
389 | unsigned long jobctl = current->jobctl; | |
390 | if (jobctl & JOBCTL_STOP_PENDING) { | |
391 | struct signal_struct *sig = current->signal; | |
392 | unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK; | |
393 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; | |
394 | if (task_set_jobctl_pending(task, signr | gstop)) { | |
395 | sig->group_stop_count++; | |
396 | } | |
397 | } | |
398 | } | |
399 | ||
c69e8d9c DH |
400 | /* |
401 | * allocate a new signal queue record | |
402 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 403 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 404 | */ |
f84d49b2 NO |
405 | static struct sigqueue * |
406 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) | |
1da177e4 LT |
407 | { |
408 | struct sigqueue *q = NULL; | |
10b1fbdb | 409 | struct user_struct *user; |
1da177e4 | 410 | |
10b1fbdb | 411 | /* |
7cf7db8d TG |
412 | * Protect access to @t credentials. This can go away when all |
413 | * callers hold rcu read lock. | |
10b1fbdb | 414 | */ |
7cf7db8d | 415 | rcu_read_lock(); |
d84f4f99 | 416 | user = get_uid(__task_cred(t)->user); |
10b1fbdb | 417 | atomic_inc(&user->sigpending); |
7cf7db8d | 418 | rcu_read_unlock(); |
f84d49b2 | 419 | |
1da177e4 | 420 | if (override_rlimit || |
10b1fbdb | 421 | atomic_read(&user->sigpending) <= |
78d7d407 | 422 | task_rlimit(t, RLIMIT_SIGPENDING)) { |
1da177e4 | 423 | q = kmem_cache_alloc(sigqueue_cachep, flags); |
f84d49b2 NO |
424 | } else { |
425 | print_dropped_signal(sig); | |
426 | } | |
427 | ||
1da177e4 | 428 | if (unlikely(q == NULL)) { |
10b1fbdb | 429 | atomic_dec(&user->sigpending); |
d84f4f99 | 430 | free_uid(user); |
1da177e4 LT |
431 | } else { |
432 | INIT_LIST_HEAD(&q->list); | |
433 | q->flags = 0; | |
d84f4f99 | 434 | q->user = user; |
1da177e4 | 435 | } |
d84f4f99 DH |
436 | |
437 | return q; | |
1da177e4 LT |
438 | } |
439 | ||
514a01b8 | 440 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
441 | { |
442 | if (q->flags & SIGQUEUE_PREALLOC) | |
443 | return; | |
444 | atomic_dec(&q->user->sigpending); | |
445 | free_uid(q->user); | |
446 | kmem_cache_free(sigqueue_cachep, q); | |
447 | } | |
448 | ||
6a14c5c9 | 449 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
450 | { |
451 | struct sigqueue *q; | |
452 | ||
453 | sigemptyset(&queue->signal); | |
454 | while (!list_empty(&queue->list)) { | |
455 | q = list_entry(queue->list.next, struct sigqueue , list); | |
456 | list_del_init(&q->list); | |
457 | __sigqueue_free(q); | |
458 | } | |
459 | } | |
460 | ||
461 | /* | |
9e7c8f8c | 462 | * Flush all pending signals for this kthread. |
1da177e4 | 463 | */ |
c81addc9 | 464 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
465 | { |
466 | unsigned long flags; | |
467 | ||
468 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
9e7c8f8c ON |
469 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
470 | flush_sigqueue(&t->pending); | |
471 | flush_sigqueue(&t->signal->shared_pending); | |
1da177e4 LT |
472 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
473 | } | |
fb50f5a4 | 474 | EXPORT_SYMBOL(flush_signals); |
1da177e4 | 475 | |
baa73d9e | 476 | #ifdef CONFIG_POSIX_TIMERS |
cbaffba1 ON |
477 | static void __flush_itimer_signals(struct sigpending *pending) |
478 | { | |
479 | sigset_t signal, retain; | |
480 | struct sigqueue *q, *n; | |
481 | ||
482 | signal = pending->signal; | |
483 | sigemptyset(&retain); | |
484 | ||
485 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
486 | int sig = q->info.si_signo; | |
487 | ||
488 | if (likely(q->info.si_code != SI_TIMER)) { | |
489 | sigaddset(&retain, sig); | |
490 | } else { | |
491 | sigdelset(&signal, sig); | |
492 | list_del_init(&q->list); | |
493 | __sigqueue_free(q); | |
494 | } | |
495 | } | |
496 | ||
497 | sigorsets(&pending->signal, &signal, &retain); | |
498 | } | |
499 | ||
500 | void flush_itimer_signals(void) | |
501 | { | |
502 | struct task_struct *tsk = current; | |
503 | unsigned long flags; | |
504 | ||
505 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
506 | __flush_itimer_signals(&tsk->pending); | |
507 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
508 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
509 | } | |
baa73d9e | 510 | #endif |
cbaffba1 | 511 | |
10ab825b ON |
512 | void ignore_signals(struct task_struct *t) |
513 | { | |
514 | int i; | |
515 | ||
516 | for (i = 0; i < _NSIG; ++i) | |
517 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
518 | ||
519 | flush_signals(t); | |
520 | } | |
521 | ||
1da177e4 LT |
522 | /* |
523 | * Flush all handlers for a task. | |
524 | */ | |
525 | ||
526 | void | |
527 | flush_signal_handlers(struct task_struct *t, int force_default) | |
528 | { | |
529 | int i; | |
530 | struct k_sigaction *ka = &t->sighand->action[0]; | |
531 | for (i = _NSIG ; i != 0 ; i--) { | |
532 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
533 | ka->sa.sa_handler = SIG_DFL; | |
534 | ka->sa.sa_flags = 0; | |
522cff14 | 535 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
536 | ka->sa.sa_restorer = NULL; |
537 | #endif | |
1da177e4 LT |
538 | sigemptyset(&ka->sa.sa_mask); |
539 | ka++; | |
540 | } | |
541 | } | |
542 | ||
67a48a24 | 543 | bool unhandled_signal(struct task_struct *tsk, int sig) |
abd4f750 | 544 | { |
445a91d2 | 545 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 546 | if (is_global_init(tsk)) |
67a48a24 CB |
547 | return true; |
548 | ||
445a91d2 | 549 | if (handler != SIG_IGN && handler != SIG_DFL) |
67a48a24 CB |
550 | return false; |
551 | ||
a288eecc TH |
552 | /* if ptraced, let the tracer determine */ |
553 | return !tsk->ptrace; | |
abd4f750 MAS |
554 | } |
555 | ||
ae7795bc | 556 | static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info, |
57db7e4a | 557 | bool *resched_timer) |
1da177e4 LT |
558 | { |
559 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 560 | |
1da177e4 LT |
561 | /* |
562 | * Collect the siginfo appropriate to this signal. Check if | |
563 | * there is another siginfo for the same signal. | |
564 | */ | |
565 | list_for_each_entry(q, &list->list, list) { | |
566 | if (q->info.si_signo == sig) { | |
d4434207 ON |
567 | if (first) |
568 | goto still_pending; | |
1da177e4 LT |
569 | first = q; |
570 | } | |
571 | } | |
d4434207 ON |
572 | |
573 | sigdelset(&list->signal, sig); | |
574 | ||
1da177e4 | 575 | if (first) { |
d4434207 | 576 | still_pending: |
1da177e4 LT |
577 | list_del_init(&first->list); |
578 | copy_siginfo(info, &first->info); | |
57db7e4a EB |
579 | |
580 | *resched_timer = | |
581 | (first->flags & SIGQUEUE_PREALLOC) && | |
582 | (info->si_code == SI_TIMER) && | |
583 | (info->si_sys_private); | |
584 | ||
1da177e4 | 585 | __sigqueue_free(first); |
1da177e4 | 586 | } else { |
5aba085e RD |
587 | /* |
588 | * Ok, it wasn't in the queue. This must be | |
589 | * a fast-pathed signal or we must have been | |
590 | * out of queue space. So zero out the info. | |
1da177e4 | 591 | */ |
faf1f22b | 592 | clear_siginfo(info); |
1da177e4 LT |
593 | info->si_signo = sig; |
594 | info->si_errno = 0; | |
7486e5d9 | 595 | info->si_code = SI_USER; |
1da177e4 LT |
596 | info->si_pid = 0; |
597 | info->si_uid = 0; | |
598 | } | |
1da177e4 LT |
599 | } |
600 | ||
601 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
ae7795bc | 602 | kernel_siginfo_t *info, bool *resched_timer) |
1da177e4 | 603 | { |
27d91e07 | 604 | int sig = next_signal(pending, mask); |
1da177e4 | 605 | |
2e01fabe | 606 | if (sig) |
57db7e4a | 607 | collect_signal(sig, pending, info, resched_timer); |
1da177e4 LT |
608 | return sig; |
609 | } | |
610 | ||
611 | /* | |
5aba085e | 612 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
613 | * expected to free it. |
614 | * | |
615 | * All callers have to hold the siglock. | |
616 | */ | |
ae7795bc | 617 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info) |
1da177e4 | 618 | { |
57db7e4a | 619 | bool resched_timer = false; |
c5363d03 | 620 | int signr; |
caec4e8d BH |
621 | |
622 | /* We only dequeue private signals from ourselves, we don't let | |
623 | * signalfd steal them | |
624 | */ | |
57db7e4a | 625 | signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer); |
8bfd9a7a | 626 | if (!signr) { |
1da177e4 | 627 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
57db7e4a | 628 | mask, info, &resched_timer); |
baa73d9e | 629 | #ifdef CONFIG_POSIX_TIMERS |
8bfd9a7a TG |
630 | /* |
631 | * itimer signal ? | |
632 | * | |
633 | * itimers are process shared and we restart periodic | |
634 | * itimers in the signal delivery path to prevent DoS | |
635 | * attacks in the high resolution timer case. This is | |
5aba085e | 636 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
637 | * itimers, as the SIGALRM is a legacy signal and only |
638 | * queued once. Changing the restart behaviour to | |
639 | * restart the timer in the signal dequeue path is | |
640 | * reducing the timer noise on heavy loaded !highres | |
641 | * systems too. | |
642 | */ | |
643 | if (unlikely(signr == SIGALRM)) { | |
644 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
645 | ||
646 | if (!hrtimer_is_queued(tmr) && | |
2456e855 | 647 | tsk->signal->it_real_incr != 0) { |
8bfd9a7a TG |
648 | hrtimer_forward(tmr, tmr->base->get_time(), |
649 | tsk->signal->it_real_incr); | |
650 | hrtimer_restart(tmr); | |
651 | } | |
652 | } | |
baa73d9e | 653 | #endif |
8bfd9a7a | 654 | } |
c5363d03 | 655 | |
b8fceee1 | 656 | recalc_sigpending(); |
c5363d03 PE |
657 | if (!signr) |
658 | return 0; | |
659 | ||
660 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
661 | /* |
662 | * Set a marker that we have dequeued a stop signal. Our | |
663 | * caller might release the siglock and then the pending | |
664 | * stop signal it is about to process is no longer in the | |
665 | * pending bitmasks, but must still be cleared by a SIGCONT | |
666 | * (and overruled by a SIGKILL). So those cases clear this | |
667 | * shared flag after we've set it. Note that this flag may | |
668 | * remain set after the signal we return is ignored or | |
669 | * handled. That doesn't matter because its only purpose | |
670 | * is to alert stop-signal processing code when another | |
671 | * processor has come along and cleared the flag. | |
672 | */ | |
a8f072c1 | 673 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 674 | } |
baa73d9e | 675 | #ifdef CONFIG_POSIX_TIMERS |
57db7e4a | 676 | if (resched_timer) { |
1da177e4 LT |
677 | /* |
678 | * Release the siglock to ensure proper locking order | |
679 | * of timer locks outside of siglocks. Note, we leave | |
680 | * irqs disabled here, since the posix-timers code is | |
681 | * about to disable them again anyway. | |
682 | */ | |
683 | spin_unlock(&tsk->sighand->siglock); | |
96fe3b07 | 684 | posixtimer_rearm(info); |
1da177e4 | 685 | spin_lock(&tsk->sighand->siglock); |
9943d3ac EB |
686 | |
687 | /* Don't expose the si_sys_private value to userspace */ | |
688 | info->si_sys_private = 0; | |
1da177e4 | 689 | } |
baa73d9e | 690 | #endif |
1da177e4 LT |
691 | return signr; |
692 | } | |
fb50f5a4 | 693 | EXPORT_SYMBOL_GPL(dequeue_signal); |
1da177e4 | 694 | |
7146db33 EB |
695 | static int dequeue_synchronous_signal(kernel_siginfo_t *info) |
696 | { | |
697 | struct task_struct *tsk = current; | |
698 | struct sigpending *pending = &tsk->pending; | |
699 | struct sigqueue *q, *sync = NULL; | |
700 | ||
701 | /* | |
702 | * Might a synchronous signal be in the queue? | |
703 | */ | |
704 | if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) | |
705 | return 0; | |
706 | ||
707 | /* | |
708 | * Return the first synchronous signal in the queue. | |
709 | */ | |
710 | list_for_each_entry(q, &pending->list, list) { | |
711 | /* Synchronous signals have a postive si_code */ | |
712 | if ((q->info.si_code > SI_USER) && | |
713 | (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) { | |
714 | sync = q; | |
715 | goto next; | |
716 | } | |
717 | } | |
718 | return 0; | |
719 | next: | |
720 | /* | |
721 | * Check if there is another siginfo for the same signal. | |
722 | */ | |
723 | list_for_each_entry_continue(q, &pending->list, list) { | |
724 | if (q->info.si_signo == sync->info.si_signo) | |
725 | goto still_pending; | |
726 | } | |
727 | ||
728 | sigdelset(&pending->signal, sync->info.si_signo); | |
729 | recalc_sigpending(); | |
730 | still_pending: | |
731 | list_del_init(&sync->list); | |
732 | copy_siginfo(info, &sync->info); | |
733 | __sigqueue_free(sync); | |
734 | return info->si_signo; | |
735 | } | |
736 | ||
1da177e4 LT |
737 | /* |
738 | * Tell a process that it has a new active signal.. | |
739 | * | |
740 | * NOTE! we rely on the previous spin_lock to | |
741 | * lock interrupts for us! We can only be called with | |
742 | * "siglock" held, and the local interrupt must | |
743 | * have been disabled when that got acquired! | |
744 | * | |
745 | * No need to set need_resched since signal event passing | |
746 | * goes through ->blocked | |
747 | */ | |
910ffdb1 | 748 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 749 | { |
1da177e4 | 750 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 | 751 | /* |
910ffdb1 | 752 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 753 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
754 | * executing another processor and just now entering stopped state. |
755 | * By using wake_up_state, we ensure the process will wake up and | |
756 | * handle its death signal. | |
757 | */ | |
910ffdb1 | 758 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
759 | kick_process(t); |
760 | } | |
761 | ||
71fabd5e GA |
762 | /* |
763 | * Remove signals in mask from the pending set and queue. | |
764 | * Returns 1 if any signals were found. | |
765 | * | |
766 | * All callers must be holding the siglock. | |
71fabd5e | 767 | */ |
8f11351e | 768 | static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
71fabd5e GA |
769 | { |
770 | struct sigqueue *q, *n; | |
771 | sigset_t m; | |
772 | ||
773 | sigandsets(&m, mask, &s->signal); | |
774 | if (sigisemptyset(&m)) | |
8f11351e | 775 | return; |
71fabd5e | 776 | |
702a5073 | 777 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
778 | list_for_each_entry_safe(q, n, &s->list, list) { |
779 | if (sigismember(mask, q->info.si_signo)) { | |
780 | list_del_init(&q->list); | |
781 | __sigqueue_free(q); | |
782 | } | |
783 | } | |
71fabd5e | 784 | } |
1da177e4 | 785 | |
ae7795bc | 786 | static inline int is_si_special(const struct kernel_siginfo *info) |
614c517d | 787 | { |
4ff4c31a | 788 | return info <= SEND_SIG_PRIV; |
614c517d ON |
789 | } |
790 | ||
ae7795bc | 791 | static inline bool si_fromuser(const struct kernel_siginfo *info) |
614c517d ON |
792 | { |
793 | return info == SEND_SIG_NOINFO || | |
794 | (!is_si_special(info) && SI_FROMUSER(info)); | |
795 | } | |
796 | ||
39fd3393 SH |
797 | /* |
798 | * called with RCU read lock from check_kill_permission() | |
799 | */ | |
2a9b9094 | 800 | static bool kill_ok_by_cred(struct task_struct *t) |
39fd3393 SH |
801 | { |
802 | const struct cred *cred = current_cred(); | |
803 | const struct cred *tcred = __task_cred(t); | |
804 | ||
2a9b9094 CB |
805 | return uid_eq(cred->euid, tcred->suid) || |
806 | uid_eq(cred->euid, tcred->uid) || | |
807 | uid_eq(cred->uid, tcred->suid) || | |
808 | uid_eq(cred->uid, tcred->uid) || | |
809 | ns_capable(tcred->user_ns, CAP_KILL); | |
39fd3393 SH |
810 | } |
811 | ||
1da177e4 LT |
812 | /* |
813 | * Bad permissions for sending the signal | |
694f690d | 814 | * - the caller must hold the RCU read lock |
1da177e4 | 815 | */ |
ae7795bc | 816 | static int check_kill_permission(int sig, struct kernel_siginfo *info, |
1da177e4 LT |
817 | struct task_struct *t) |
818 | { | |
2e2ba22e | 819 | struct pid *sid; |
3b5e9e53 ON |
820 | int error; |
821 | ||
7ed20e1a | 822 | if (!valid_signal(sig)) |
3b5e9e53 ON |
823 | return -EINVAL; |
824 | ||
614c517d | 825 | if (!si_fromuser(info)) |
3b5e9e53 | 826 | return 0; |
e54dc243 | 827 | |
3b5e9e53 ON |
828 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
829 | if (error) | |
1da177e4 | 830 | return error; |
3b5e9e53 | 831 | |
065add39 | 832 | if (!same_thread_group(current, t) && |
39fd3393 | 833 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
834 | switch (sig) { |
835 | case SIGCONT: | |
2e2ba22e | 836 | sid = task_session(t); |
2e2ba22e ON |
837 | /* |
838 | * We don't return the error if sid == NULL. The | |
839 | * task was unhashed, the caller must notice this. | |
840 | */ | |
841 | if (!sid || sid == task_session(current)) | |
842 | break; | |
b028fb61 | 843 | /* fall through */ |
2e2ba22e ON |
844 | default: |
845 | return -EPERM; | |
846 | } | |
847 | } | |
c2f0c7c3 | 848 | |
6b4f3d01 | 849 | return security_task_kill(t, info, sig, NULL); |
1da177e4 LT |
850 | } |
851 | ||
fb1d910c TH |
852 | /** |
853 | * ptrace_trap_notify - schedule trap to notify ptracer | |
854 | * @t: tracee wanting to notify tracer | |
855 | * | |
856 | * This function schedules sticky ptrace trap which is cleared on the next | |
857 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
858 | * ptracer. | |
859 | * | |
544b2c91 TH |
860 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
861 | * ptracer is listening for events, tracee is woken up so that it can | |
862 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
863 | * eventually taken without returning to userland after the existing traps | |
864 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
865 | * |
866 | * CONTEXT: | |
867 | * Must be called with @task->sighand->siglock held. | |
868 | */ | |
869 | static void ptrace_trap_notify(struct task_struct *t) | |
870 | { | |
871 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
872 | assert_spin_locked(&t->sighand->siglock); | |
873 | ||
874 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 875 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
876 | } |
877 | ||
1da177e4 | 878 | /* |
7e695a5e ON |
879 | * Handle magic process-wide effects of stop/continue signals. Unlike |
880 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
881 | * time regardless of blocking, ignoring, or handling. This does the |
882 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
883 | * signals. The process stop is done as a signal action for SIG_DFL. |
884 | * | |
885 | * Returns true if the signal should be actually delivered, otherwise | |
886 | * it should be dropped. | |
1da177e4 | 887 | */ |
403bad72 | 888 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 889 | { |
ad16a460 | 890 | struct signal_struct *signal = p->signal; |
1da177e4 | 891 | struct task_struct *t; |
9490592f | 892 | sigset_t flush; |
1da177e4 | 893 | |
403bad72 | 894 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { |
5fa534c9 | 895 | if (!(signal->flags & SIGNAL_GROUP_EXIT)) |
403bad72 | 896 | return sig == SIGKILL; |
1da177e4 | 897 | /* |
7e695a5e | 898 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 899 | */ |
7e695a5e | 900 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
901 | /* |
902 | * This is a stop signal. Remove SIGCONT from all queues. | |
903 | */ | |
9490592f | 904 | siginitset(&flush, sigmask(SIGCONT)); |
c09c1441 | 905 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 906 | for_each_thread(p, t) |
c09c1441 | 907 | flush_sigqueue_mask(&flush, &t->pending); |
1da177e4 | 908 | } else if (sig == SIGCONT) { |
fc321d2e | 909 | unsigned int why; |
1da177e4 | 910 | /* |
1deac632 | 911 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 912 | */ |
9490592f | 913 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
c09c1441 | 914 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 915 | for_each_thread(p, t) { |
c09c1441 | 916 | flush_sigqueue_mask(&flush, &t->pending); |
3759a0d9 | 917 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
fb1d910c TH |
918 | if (likely(!(t->ptrace & PT_SEIZED))) |
919 | wake_up_state(t, __TASK_STOPPED); | |
920 | else | |
921 | ptrace_trap_notify(t); | |
9490592f | 922 | } |
1da177e4 | 923 | |
fc321d2e ON |
924 | /* |
925 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
926 | * | |
927 | * If we were in the middle of a group stop, we pretend it | |
928 | * was already finished, and then continued. Since SIGCHLD | |
929 | * doesn't queue we report only CLD_STOPPED, as if the next | |
930 | * CLD_CONTINUED was dropped. | |
931 | */ | |
932 | why = 0; | |
ad16a460 | 933 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 934 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 935 | else if (signal->group_stop_count) |
fc321d2e ON |
936 | why |= SIGNAL_CLD_STOPPED; |
937 | ||
938 | if (why) { | |
021e1ae3 | 939 | /* |
ae6d2ed7 | 940 | * The first thread which returns from do_signal_stop() |
021e1ae3 | 941 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
2e58f57d | 942 | * notify its parent. See get_signal(). |
021e1ae3 | 943 | */ |
2d39b3cd | 944 | signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
ad16a460 ON |
945 | signal->group_stop_count = 0; |
946 | signal->group_exit_code = 0; | |
1da177e4 | 947 | } |
1da177e4 | 948 | } |
7e695a5e | 949 | |
def8cf72 | 950 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
951 | } |
952 | ||
71f11dc0 ON |
953 | /* |
954 | * Test if P wants to take SIG. After we've checked all threads with this, | |
955 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
956 | * blocking SIG were ruled out because they are not running and already | |
957 | * have pending signals. Such threads will dequeue from the shared queue | |
958 | * as soon as they're available, so putting the signal on the shared queue | |
959 | * will be equivalent to sending it to one such thread. | |
960 | */ | |
acd14e62 | 961 | static inline bool wants_signal(int sig, struct task_struct *p) |
71f11dc0 ON |
962 | { |
963 | if (sigismember(&p->blocked, sig)) | |
acd14e62 CB |
964 | return false; |
965 | ||
71f11dc0 | 966 | if (p->flags & PF_EXITING) |
acd14e62 CB |
967 | return false; |
968 | ||
71f11dc0 | 969 | if (sig == SIGKILL) |
acd14e62 CB |
970 | return true; |
971 | ||
71f11dc0 | 972 | if (task_is_stopped_or_traced(p)) |
acd14e62 CB |
973 | return false; |
974 | ||
71f11dc0 ON |
975 | return task_curr(p) || !signal_pending(p); |
976 | } | |
977 | ||
07296149 | 978 | static void complete_signal(int sig, struct task_struct *p, enum pid_type type) |
71f11dc0 ON |
979 | { |
980 | struct signal_struct *signal = p->signal; | |
981 | struct task_struct *t; | |
982 | ||
983 | /* | |
984 | * Now find a thread we can wake up to take the signal off the queue. | |
985 | * | |
986 | * If the main thread wants the signal, it gets first crack. | |
987 | * Probably the least surprising to the average bear. | |
988 | */ | |
989 | if (wants_signal(sig, p)) | |
990 | t = p; | |
07296149 | 991 | else if ((type == PIDTYPE_PID) || thread_group_empty(p)) |
71f11dc0 ON |
992 | /* |
993 | * There is just one thread and it does not need to be woken. | |
994 | * It will dequeue unblocked signals before it runs again. | |
995 | */ | |
996 | return; | |
997 | else { | |
998 | /* | |
999 | * Otherwise try to find a suitable thread. | |
1000 | */ | |
1001 | t = signal->curr_target; | |
1002 | while (!wants_signal(sig, t)) { | |
1003 | t = next_thread(t); | |
1004 | if (t == signal->curr_target) | |
1005 | /* | |
1006 | * No thread needs to be woken. | |
1007 | * Any eligible threads will see | |
1008 | * the signal in the queue soon. | |
1009 | */ | |
1010 | return; | |
1011 | } | |
1012 | signal->curr_target = t; | |
1013 | } | |
1014 | ||
1015 | /* | |
1016 | * Found a killable thread. If the signal will be fatal, | |
1017 | * then start taking the whole group down immediately. | |
1018 | */ | |
fae5fa44 | 1019 | if (sig_fatal(p, sig) && |
42691579 | 1020 | !(signal->flags & SIGNAL_GROUP_EXIT) && |
71f11dc0 | 1021 | !sigismember(&t->real_blocked, sig) && |
42691579 | 1022 | (sig == SIGKILL || !p->ptrace)) { |
71f11dc0 ON |
1023 | /* |
1024 | * This signal will be fatal to the whole group. | |
1025 | */ | |
1026 | if (!sig_kernel_coredump(sig)) { | |
1027 | /* | |
1028 | * Start a group exit and wake everybody up. | |
1029 | * This way we don't have other threads | |
1030 | * running and doing things after a slower | |
1031 | * thread has the fatal signal pending. | |
1032 | */ | |
1033 | signal->flags = SIGNAL_GROUP_EXIT; | |
1034 | signal->group_exit_code = sig; | |
1035 | signal->group_stop_count = 0; | |
1036 | t = p; | |
1037 | do { | |
6dfca329 | 1038 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
1039 | sigaddset(&t->pending.signal, SIGKILL); |
1040 | signal_wake_up(t, 1); | |
1041 | } while_each_thread(p, t); | |
1042 | return; | |
1043 | } | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * The signal is already in the shared-pending queue. | |
1048 | * Tell the chosen thread to wake up and dequeue it. | |
1049 | */ | |
1050 | signal_wake_up(t, sig == SIGKILL); | |
1051 | return; | |
1052 | } | |
1053 | ||
a19e2c01 | 1054 | static inline bool legacy_queue(struct sigpending *signals, int sig) |
af7fff9c PE |
1055 | { |
1056 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
1057 | } | |
1058 | ||
6b550f94 | 1059 | #ifdef CONFIG_USER_NS |
ae7795bc | 1060 | static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t) |
6b550f94 SH |
1061 | { |
1062 | if (current_user_ns() == task_cred_xxx(t, user_ns)) | |
1063 | return; | |
1064 | ||
1065 | if (SI_FROMKERNEL(info)) | |
1066 | return; | |
1067 | ||
078de5f7 EB |
1068 | rcu_read_lock(); |
1069 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns), | |
1070 | make_kuid(current_user_ns(), info->si_uid)); | |
1071 | rcu_read_unlock(); | |
6b550f94 SH |
1072 | } |
1073 | #else | |
ae7795bc | 1074 | static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t) |
6b550f94 SH |
1075 | { |
1076 | return; | |
1077 | } | |
1078 | #endif | |
1079 | ||
ae7795bc | 1080 | static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t, |
5a883cee | 1081 | enum pid_type type, int from_ancestor_ns) |
1da177e4 | 1082 | { |
2ca3515a | 1083 | struct sigpending *pending; |
6e65acba | 1084 | struct sigqueue *q; |
7a0aeb14 | 1085 | int override_rlimit; |
6c303d3a | 1086 | int ret = 0, result; |
0a16b607 | 1087 | |
6e65acba | 1088 | assert_spin_locked(&t->sighand->siglock); |
921cf9f6 | 1089 | |
6c303d3a | 1090 | result = TRACE_SIGNAL_IGNORED; |
629d362b | 1091 | if (!prepare_signal(sig, t, |
4ff4c31a | 1092 | from_ancestor_ns || (info == SEND_SIG_PRIV))) |
6c303d3a | 1093 | goto ret; |
2ca3515a | 1094 | |
5a883cee | 1095 | pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
2acb024d PE |
1096 | /* |
1097 | * Short-circuit ignored signals and support queuing | |
1098 | * exactly one non-rt signal, so that we can get more | |
1099 | * detailed information about the cause of the signal. | |
1100 | */ | |
6c303d3a | 1101 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1102 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1103 | goto ret; |
1104 | ||
1105 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 | 1106 | /* |
a692933a | 1107 | * Skip useless siginfo allocation for SIGKILL and kernel threads. |
1da177e4 | 1108 | */ |
a692933a | 1109 | if ((sig == SIGKILL) || (t->flags & PF_KTHREAD)) |
1da177e4 LT |
1110 | goto out_set; |
1111 | ||
5aba085e RD |
1112 | /* |
1113 | * Real-time signals must be queued if sent by sigqueue, or | |
1114 | * some other real-time mechanism. It is implementation | |
1115 | * defined whether kill() does so. We attempt to do so, on | |
1116 | * the principle of least surprise, but since kill is not | |
1117 | * allowed to fail with EAGAIN when low on memory we just | |
1118 | * make sure at least one signal gets delivered and don't | |
1119 | * pass on the info struct. | |
1120 | */ | |
7a0aeb14 VN |
1121 | if (sig < SIGRTMIN) |
1122 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1123 | else | |
1124 | override_rlimit = 0; | |
1125 | ||
75f296d9 | 1126 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit); |
1da177e4 | 1127 | if (q) { |
2ca3515a | 1128 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1129 | switch ((unsigned long) info) { |
b67a1b9e | 1130 | case (unsigned long) SEND_SIG_NOINFO: |
faf1f22b | 1131 | clear_siginfo(&q->info); |
1da177e4 LT |
1132 | q->info.si_signo = sig; |
1133 | q->info.si_errno = 0; | |
1134 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1135 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1136 | task_active_pid_ns(t)); |
078de5f7 | 1137 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 | 1138 | break; |
b67a1b9e | 1139 | case (unsigned long) SEND_SIG_PRIV: |
faf1f22b | 1140 | clear_siginfo(&q->info); |
1da177e4 LT |
1141 | q->info.si_signo = sig; |
1142 | q->info.si_errno = 0; | |
1143 | q->info.si_code = SI_KERNEL; | |
1144 | q->info.si_pid = 0; | |
1145 | q->info.si_uid = 0; | |
1146 | break; | |
1147 | default: | |
1148 | copy_siginfo(&q->info, info); | |
6588c1e3 SB |
1149 | if (from_ancestor_ns) |
1150 | q->info.si_pid = 0; | |
1da177e4 LT |
1151 | break; |
1152 | } | |
6b550f94 SH |
1153 | |
1154 | userns_fixup_signal_uid(&q->info, t); | |
1155 | ||
621d3121 | 1156 | } else if (!is_si_special(info)) { |
ba005e1f MH |
1157 | if (sig >= SIGRTMIN && info->si_code != SI_USER) { |
1158 | /* | |
1159 | * Queue overflow, abort. We may abort if the | |
1160 | * signal was rt and sent by user using something | |
1161 | * other than kill(). | |
1162 | */ | |
6c303d3a ON |
1163 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
1164 | ret = -EAGAIN; | |
1165 | goto ret; | |
ba005e1f MH |
1166 | } else { |
1167 | /* | |
1168 | * This is a silent loss of information. We still | |
1169 | * send the signal, but the *info bits are lost. | |
1170 | */ | |
6c303d3a | 1171 | result = TRACE_SIGNAL_LOSE_INFO; |
ba005e1f | 1172 | } |
1da177e4 LT |
1173 | } |
1174 | ||
1175 | out_set: | |
53c30337 | 1176 | signalfd_notify(t, sig); |
2ca3515a | 1177 | sigaddset(&pending->signal, sig); |
c3ad2c3b EB |
1178 | |
1179 | /* Let multiprocess signals appear after on-going forks */ | |
1180 | if (type > PIDTYPE_TGID) { | |
1181 | struct multiprocess_signals *delayed; | |
1182 | hlist_for_each_entry(delayed, &t->signal->multiprocess, node) { | |
1183 | sigset_t *signal = &delayed->signal; | |
1184 | /* Can't queue both a stop and a continue signal */ | |
1185 | if (sig == SIGCONT) | |
1186 | sigdelsetmask(signal, SIG_KERNEL_STOP_MASK); | |
1187 | else if (sig_kernel_stop(sig)) | |
1188 | sigdelset(signal, SIGCONT); | |
1189 | sigaddset(signal, sig); | |
1190 | } | |
1191 | } | |
1192 | ||
07296149 | 1193 | complete_signal(sig, t, type); |
6c303d3a | 1194 | ret: |
5a883cee | 1195 | trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result); |
6c303d3a | 1196 | return ret; |
1da177e4 LT |
1197 | } |
1198 | ||
ae7795bc | 1199 | static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t, |
b213984b | 1200 | enum pid_type type) |
7978b567 | 1201 | { |
921cf9f6 SB |
1202 | int from_ancestor_ns = 0; |
1203 | ||
1204 | #ifdef CONFIG_PID_NS | |
dd34200a ON |
1205 | from_ancestor_ns = si_fromuser(info) && |
1206 | !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
921cf9f6 SB |
1207 | #endif |
1208 | ||
5a883cee | 1209 | return __send_signal(sig, info, t, type, from_ancestor_ns); |
7978b567 SB |
1210 | } |
1211 | ||
4aaefee5 | 1212 | static void print_fatal_signal(int signr) |
45807a1d | 1213 | { |
4aaefee5 | 1214 | struct pt_regs *regs = signal_pt_regs(); |
747800ef | 1215 | pr_info("potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1216 | |
ca5cd877 | 1217 | #if defined(__i386__) && !defined(__arch_um__) |
747800ef | 1218 | pr_info("code at %08lx: ", regs->ip); |
45807a1d IM |
1219 | { |
1220 | int i; | |
1221 | for (i = 0; i < 16; i++) { | |
1222 | unsigned char insn; | |
1223 | ||
b45c6e76 AK |
1224 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1225 | break; | |
747800ef | 1226 | pr_cont("%02x ", insn); |
45807a1d IM |
1227 | } |
1228 | } | |
747800ef | 1229 | pr_cont("\n"); |
45807a1d | 1230 | #endif |
3a9f84d3 | 1231 | preempt_disable(); |
45807a1d | 1232 | show_regs(regs); |
3a9f84d3 | 1233 | preempt_enable(); |
45807a1d IM |
1234 | } |
1235 | ||
1236 | static int __init setup_print_fatal_signals(char *str) | |
1237 | { | |
1238 | get_option (&str, &print_fatal_signals); | |
1239 | ||
1240 | return 1; | |
1241 | } | |
1242 | ||
1243 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1244 | |
4cd4b6d4 | 1245 | int |
ae7795bc | 1246 | __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p) |
4cd4b6d4 | 1247 | { |
b213984b | 1248 | return send_signal(sig, info, p, PIDTYPE_TGID); |
4cd4b6d4 PE |
1249 | } |
1250 | ||
ae7795bc | 1251 | int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p, |
40b3b025 | 1252 | enum pid_type type) |
4a30debf ON |
1253 | { |
1254 | unsigned long flags; | |
1255 | int ret = -ESRCH; | |
1256 | ||
1257 | if (lock_task_sighand(p, &flags)) { | |
b213984b | 1258 | ret = send_signal(sig, info, p, type); |
4a30debf ON |
1259 | unlock_task_sighand(p, &flags); |
1260 | } | |
1261 | ||
1262 | return ret; | |
1263 | } | |
1264 | ||
1da177e4 LT |
1265 | /* |
1266 | * Force a signal that the process can't ignore: if necessary | |
1267 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1268 | * |
1269 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1270 | * since we do not want to have a signal handler that was blocked | |
1271 | * be invoked when user space had explicitly blocked it. | |
1272 | * | |
80fe728d ON |
1273 | * We don't want to have recursive SIGSEGV's etc, for example, |
1274 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1275 | */ |
1da177e4 | 1276 | int |
ae7795bc | 1277 | force_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *t) |
1da177e4 LT |
1278 | { |
1279 | unsigned long int flags; | |
ae74c3b6 LT |
1280 | int ret, blocked, ignored; |
1281 | struct k_sigaction *action; | |
1da177e4 LT |
1282 | |
1283 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1284 | action = &t->sighand->action[sig-1]; |
1285 | ignored = action->sa.sa_handler == SIG_IGN; | |
1286 | blocked = sigismember(&t->blocked, sig); | |
1287 | if (blocked || ignored) { | |
1288 | action->sa.sa_handler = SIG_DFL; | |
1289 | if (blocked) { | |
1290 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1291 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1292 | } |
1da177e4 | 1293 | } |
eb61b591 JI |
1294 | /* |
1295 | * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect | |
1296 | * debugging to leave init killable. | |
1297 | */ | |
1298 | if (action->sa.sa_handler == SIG_DFL && !t->ptrace) | |
80fe728d | 1299 | t->signal->flags &= ~SIGNAL_UNKILLABLE; |
b21c5bd5 | 1300 | ret = send_signal(sig, info, t, PIDTYPE_PID); |
1da177e4 LT |
1301 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
1302 | ||
1303 | return ret; | |
1304 | } | |
1305 | ||
1da177e4 LT |
1306 | /* |
1307 | * Nuke all other threads in the group. | |
1308 | */ | |
09faef11 | 1309 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1310 | { |
09faef11 ON |
1311 | struct task_struct *t = p; |
1312 | int count = 0; | |
1da177e4 | 1313 | |
1da177e4 LT |
1314 | p->signal->group_stop_count = 0; |
1315 | ||
09faef11 | 1316 | while_each_thread(p, t) { |
6dfca329 | 1317 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1318 | count++; |
1319 | ||
1320 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1321 | if (t->exit_state) |
1322 | continue; | |
1da177e4 | 1323 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1324 | signal_wake_up(t, 1); |
1325 | } | |
09faef11 ON |
1326 | |
1327 | return count; | |
1da177e4 LT |
1328 | } |
1329 | ||
b8ed374e NK |
1330 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1331 | unsigned long *flags) | |
f63ee72e ON |
1332 | { |
1333 | struct sighand_struct *sighand; | |
1334 | ||
59dc6f3c | 1335 | rcu_read_lock(); |
f63ee72e ON |
1336 | for (;;) { |
1337 | sighand = rcu_dereference(tsk->sighand); | |
59dc6f3c | 1338 | if (unlikely(sighand == NULL)) |
f63ee72e | 1339 | break; |
59dc6f3c | 1340 | |
392809b2 ON |
1341 | /* |
1342 | * This sighand can be already freed and even reused, but | |
5f0d5a3a | 1343 | * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which |
392809b2 ON |
1344 | * initializes ->siglock: this slab can't go away, it has |
1345 | * the same object type, ->siglock can't be reinitialized. | |
1346 | * | |
1347 | * We need to ensure that tsk->sighand is still the same | |
1348 | * after we take the lock, we can race with de_thread() or | |
1349 | * __exit_signal(). In the latter case the next iteration | |
1350 | * must see ->sighand == NULL. | |
1351 | */ | |
59dc6f3c AMG |
1352 | spin_lock_irqsave(&sighand->siglock, *flags); |
1353 | if (likely(sighand == tsk->sighand)) | |
f63ee72e | 1354 | break; |
59dc6f3c | 1355 | spin_unlock_irqrestore(&sighand->siglock, *flags); |
f63ee72e | 1356 | } |
59dc6f3c | 1357 | rcu_read_unlock(); |
f63ee72e ON |
1358 | |
1359 | return sighand; | |
1360 | } | |
1361 | ||
c69e8d9c DH |
1362 | /* |
1363 | * send signal info to all the members of a group | |
c69e8d9c | 1364 | */ |
ae7795bc EB |
1365 | int group_send_sig_info(int sig, struct kernel_siginfo *info, |
1366 | struct task_struct *p, enum pid_type type) | |
1da177e4 | 1367 | { |
694f690d DH |
1368 | int ret; |
1369 | ||
1370 | rcu_read_lock(); | |
1371 | ret = check_kill_permission(sig, info, p); | |
1372 | rcu_read_unlock(); | |
f63ee72e | 1373 | |
4a30debf | 1374 | if (!ret && sig) |
40b3b025 | 1375 | ret = do_send_sig_info(sig, info, p, type); |
1da177e4 LT |
1376 | |
1377 | return ret; | |
1378 | } | |
1379 | ||
1380 | /* | |
146a505d | 1381 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1382 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1383 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1384 | */ |
ae7795bc | 1385 | int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1386 | { |
1387 | struct task_struct *p = NULL; | |
1388 | int retval, success; | |
1389 | ||
1da177e4 LT |
1390 | success = 0; |
1391 | retval = -ESRCH; | |
c4b92fc1 | 1392 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
01024980 | 1393 | int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID); |
1da177e4 LT |
1394 | success |= !err; |
1395 | retval = err; | |
c4b92fc1 | 1396 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1397 | return success ? 0 : retval; |
1398 | } | |
1399 | ||
ae7795bc | 1400 | int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) |
1da177e4 | 1401 | { |
d36174bc | 1402 | int error = -ESRCH; |
1da177e4 LT |
1403 | struct task_struct *p; |
1404 | ||
eca1a089 PM |
1405 | for (;;) { |
1406 | rcu_read_lock(); | |
1407 | p = pid_task(pid, PIDTYPE_PID); | |
1408 | if (p) | |
01024980 | 1409 | error = group_send_sig_info(sig, info, p, PIDTYPE_TGID); |
eca1a089 PM |
1410 | rcu_read_unlock(); |
1411 | if (likely(!p || error != -ESRCH)) | |
1412 | return error; | |
6ca25b55 | 1413 | |
eca1a089 PM |
1414 | /* |
1415 | * The task was unhashed in between, try again. If it | |
1416 | * is dead, pid_task() will return NULL, if we race with | |
1417 | * de_thread() it will find the new leader. | |
1418 | */ | |
1419 | } | |
1da177e4 LT |
1420 | } |
1421 | ||
ae7795bc | 1422 | static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid) |
c4b92fc1 EB |
1423 | { |
1424 | int error; | |
1425 | rcu_read_lock(); | |
b488893a | 1426 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1427 | rcu_read_unlock(); |
1428 | return error; | |
1429 | } | |
1430 | ||
bb17fcca CB |
1431 | static inline bool kill_as_cred_perm(const struct cred *cred, |
1432 | struct task_struct *target) | |
d178bc3a SH |
1433 | { |
1434 | const struct cred *pcred = __task_cred(target); | |
bb17fcca CB |
1435 | |
1436 | return uid_eq(cred->euid, pcred->suid) || | |
1437 | uid_eq(cred->euid, pcred->uid) || | |
1438 | uid_eq(cred->uid, pcred->suid) || | |
1439 | uid_eq(cred->uid, pcred->uid); | |
d178bc3a SH |
1440 | } |
1441 | ||
2425c08b | 1442 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
ae7795bc | 1443 | int kill_pid_info_as_cred(int sig, struct kernel_siginfo *info, struct pid *pid, |
6b4f3d01 | 1444 | const struct cred *cred) |
46113830 HW |
1445 | { |
1446 | int ret = -EINVAL; | |
1447 | struct task_struct *p; | |
14d8c9f3 | 1448 | unsigned long flags; |
46113830 HW |
1449 | |
1450 | if (!valid_signal(sig)) | |
1451 | return ret; | |
1452 | ||
14d8c9f3 | 1453 | rcu_read_lock(); |
2425c08b | 1454 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1455 | if (!p) { |
1456 | ret = -ESRCH; | |
1457 | goto out_unlock; | |
1458 | } | |
d178bc3a | 1459 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) { |
46113830 HW |
1460 | ret = -EPERM; |
1461 | goto out_unlock; | |
1462 | } | |
6b4f3d01 | 1463 | ret = security_task_kill(p, info, sig, cred); |
8f95dc58 DQ |
1464 | if (ret) |
1465 | goto out_unlock; | |
14d8c9f3 TG |
1466 | |
1467 | if (sig) { | |
1468 | if (lock_task_sighand(p, &flags)) { | |
5a883cee | 1469 | ret = __send_signal(sig, info, p, PIDTYPE_TGID, 0); |
14d8c9f3 TG |
1470 | unlock_task_sighand(p, &flags); |
1471 | } else | |
1472 | ret = -ESRCH; | |
46113830 HW |
1473 | } |
1474 | out_unlock: | |
14d8c9f3 | 1475 | rcu_read_unlock(); |
46113830 HW |
1476 | return ret; |
1477 | } | |
d178bc3a | 1478 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred); |
1da177e4 LT |
1479 | |
1480 | /* | |
1481 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1482 | * | |
1483 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1484 | * is probably wrong. Should make it like BSD or SYSV. | |
1485 | */ | |
1486 | ||
ae7795bc | 1487 | static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid) |
1da177e4 | 1488 | { |
8d42db18 | 1489 | int ret; |
d5df763b PE |
1490 | |
1491 | if (pid > 0) { | |
1492 | rcu_read_lock(); | |
1493 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1494 | rcu_read_unlock(); | |
1495 | return ret; | |
1496 | } | |
1497 | ||
4ea77014 | 1498 | /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */ |
1499 | if (pid == INT_MIN) | |
1500 | return -ESRCH; | |
1501 | ||
d5df763b PE |
1502 | read_lock(&tasklist_lock); |
1503 | if (pid != -1) { | |
1504 | ret = __kill_pgrp_info(sig, info, | |
1505 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1506 | } else { | |
1da177e4 LT |
1507 | int retval = 0, count = 0; |
1508 | struct task_struct * p; | |
1509 | ||
1da177e4 | 1510 | for_each_process(p) { |
d25141a8 SB |
1511 | if (task_pid_vnr(p) > 1 && |
1512 | !same_thread_group(p, current)) { | |
01024980 EB |
1513 | int err = group_send_sig_info(sig, info, p, |
1514 | PIDTYPE_MAX); | |
1da177e4 LT |
1515 | ++count; |
1516 | if (err != -EPERM) | |
1517 | retval = err; | |
1518 | } | |
1519 | } | |
8d42db18 | 1520 | ret = count ? retval : -ESRCH; |
1da177e4 | 1521 | } |
d5df763b PE |
1522 | read_unlock(&tasklist_lock); |
1523 | ||
8d42db18 | 1524 | return ret; |
1da177e4 LT |
1525 | } |
1526 | ||
1527 | /* | |
1528 | * These are for backward compatibility with the rest of the kernel source. | |
1529 | */ | |
1530 | ||
ae7795bc | 1531 | int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p) |
1da177e4 | 1532 | { |
1da177e4 LT |
1533 | /* |
1534 | * Make sure legacy kernel users don't send in bad values | |
1535 | * (normal paths check this in check_kill_permission). | |
1536 | */ | |
7ed20e1a | 1537 | if (!valid_signal(sig)) |
1da177e4 LT |
1538 | return -EINVAL; |
1539 | ||
40b3b025 | 1540 | return do_send_sig_info(sig, info, p, PIDTYPE_PID); |
1da177e4 | 1541 | } |
fb50f5a4 | 1542 | EXPORT_SYMBOL(send_sig_info); |
1da177e4 | 1543 | |
b67a1b9e ON |
1544 | #define __si_special(priv) \ |
1545 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1546 | ||
1da177e4 LT |
1547 | int |
1548 | send_sig(int sig, struct task_struct *p, int priv) | |
1549 | { | |
b67a1b9e | 1550 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 | 1551 | } |
fb50f5a4 | 1552 | EXPORT_SYMBOL(send_sig); |
1da177e4 | 1553 | |
52cba1a2 | 1554 | void force_sig(int sig, struct task_struct *p) |
1da177e4 | 1555 | { |
b67a1b9e | 1556 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 | 1557 | } |
fb50f5a4 | 1558 | EXPORT_SYMBOL(force_sig); |
1da177e4 LT |
1559 | |
1560 | /* | |
1561 | * When things go south during signal handling, we | |
1562 | * will force a SIGSEGV. And if the signal that caused | |
1563 | * the problem was already a SIGSEGV, we'll want to | |
1564 | * make sure we don't even try to deliver the signal.. | |
1565 | */ | |
52cba1a2 | 1566 | void force_sigsegv(int sig, struct task_struct *p) |
1da177e4 LT |
1567 | { |
1568 | if (sig == SIGSEGV) { | |
1569 | unsigned long flags; | |
1570 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1571 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1572 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1573 | } | |
1574 | force_sig(SIGSEGV, p); | |
1da177e4 LT |
1575 | } |
1576 | ||
f8ec6601 EB |
1577 | int force_sig_fault(int sig, int code, void __user *addr |
1578 | ___ARCH_SI_TRAPNO(int trapno) | |
1579 | ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr) | |
1580 | , struct task_struct *t) | |
1581 | { | |
ae7795bc | 1582 | struct kernel_siginfo info; |
f8ec6601 EB |
1583 | |
1584 | clear_siginfo(&info); | |
1585 | info.si_signo = sig; | |
1586 | info.si_errno = 0; | |
1587 | info.si_code = code; | |
1588 | info.si_addr = addr; | |
1589 | #ifdef __ARCH_SI_TRAPNO | |
1590 | info.si_trapno = trapno; | |
1591 | #endif | |
1592 | #ifdef __ia64__ | |
1593 | info.si_imm = imm; | |
1594 | info.si_flags = flags; | |
1595 | info.si_isr = isr; | |
1596 | #endif | |
1597 | return force_sig_info(info.si_signo, &info, t); | |
1598 | } | |
1599 | ||
1600 | int send_sig_fault(int sig, int code, void __user *addr | |
1601 | ___ARCH_SI_TRAPNO(int trapno) | |
1602 | ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr) | |
1603 | , struct task_struct *t) | |
1604 | { | |
ae7795bc | 1605 | struct kernel_siginfo info; |
f8ec6601 EB |
1606 | |
1607 | clear_siginfo(&info); | |
1608 | info.si_signo = sig; | |
1609 | info.si_errno = 0; | |
1610 | info.si_code = code; | |
1611 | info.si_addr = addr; | |
1612 | #ifdef __ARCH_SI_TRAPNO | |
1613 | info.si_trapno = trapno; | |
1614 | #endif | |
1615 | #ifdef __ia64__ | |
1616 | info.si_imm = imm; | |
1617 | info.si_flags = flags; | |
1618 | info.si_isr = isr; | |
1619 | #endif | |
1620 | return send_sig_info(info.si_signo, &info, t); | |
1621 | } | |
1622 | ||
38246735 EB |
1623 | int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t) |
1624 | { | |
ae7795bc | 1625 | struct kernel_siginfo info; |
38246735 EB |
1626 | |
1627 | WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); | |
1628 | clear_siginfo(&info); | |
1629 | info.si_signo = SIGBUS; | |
1630 | info.si_errno = 0; | |
1631 | info.si_code = code; | |
1632 | info.si_addr = addr; | |
1633 | info.si_addr_lsb = lsb; | |
1634 | return force_sig_info(info.si_signo, &info, t); | |
1635 | } | |
1636 | ||
1637 | int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t) | |
1638 | { | |
ae7795bc | 1639 | struct kernel_siginfo info; |
38246735 EB |
1640 | |
1641 | WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); | |
1642 | clear_siginfo(&info); | |
1643 | info.si_signo = SIGBUS; | |
1644 | info.si_errno = 0; | |
1645 | info.si_code = code; | |
1646 | info.si_addr = addr; | |
1647 | info.si_addr_lsb = lsb; | |
1648 | return send_sig_info(info.si_signo, &info, t); | |
1649 | } | |
1650 | EXPORT_SYMBOL(send_sig_mceerr); | |
38246735 | 1651 | |
38246735 EB |
1652 | int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper) |
1653 | { | |
ae7795bc | 1654 | struct kernel_siginfo info; |
38246735 EB |
1655 | |
1656 | clear_siginfo(&info); | |
1657 | info.si_signo = SIGSEGV; | |
1658 | info.si_errno = 0; | |
1659 | info.si_code = SEGV_BNDERR; | |
1660 | info.si_addr = addr; | |
1661 | info.si_lower = lower; | |
1662 | info.si_upper = upper; | |
1663 | return force_sig_info(info.si_signo, &info, current); | |
1664 | } | |
38246735 EB |
1665 | |
1666 | #ifdef SEGV_PKUERR | |
1667 | int force_sig_pkuerr(void __user *addr, u32 pkey) | |
1668 | { | |
ae7795bc | 1669 | struct kernel_siginfo info; |
38246735 EB |
1670 | |
1671 | clear_siginfo(&info); | |
1672 | info.si_signo = SIGSEGV; | |
1673 | info.si_errno = 0; | |
1674 | info.si_code = SEGV_PKUERR; | |
1675 | info.si_addr = addr; | |
1676 | info.si_pkey = pkey; | |
1677 | return force_sig_info(info.si_signo, &info, current); | |
1678 | } | |
1679 | #endif | |
f8ec6601 | 1680 | |
f71dd7dc EB |
1681 | /* For the crazy architectures that include trap information in |
1682 | * the errno field, instead of an actual errno value. | |
1683 | */ | |
1684 | int force_sig_ptrace_errno_trap(int errno, void __user *addr) | |
1685 | { | |
ae7795bc | 1686 | struct kernel_siginfo info; |
f71dd7dc EB |
1687 | |
1688 | clear_siginfo(&info); | |
1689 | info.si_signo = SIGTRAP; | |
1690 | info.si_errno = errno; | |
1691 | info.si_code = TRAP_HWBKPT; | |
1692 | info.si_addr = addr; | |
1693 | return force_sig_info(info.si_signo, &info, current); | |
1694 | } | |
1695 | ||
c4b92fc1 EB |
1696 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1697 | { | |
146a505d PE |
1698 | int ret; |
1699 | ||
1700 | read_lock(&tasklist_lock); | |
1701 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1702 | read_unlock(&tasklist_lock); | |
1703 | ||
1704 | return ret; | |
c4b92fc1 EB |
1705 | } |
1706 | EXPORT_SYMBOL(kill_pgrp); | |
1707 | ||
1708 | int kill_pid(struct pid *pid, int sig, int priv) | |
1709 | { | |
1710 | return kill_pid_info(sig, __si_special(priv), pid); | |
1711 | } | |
1712 | EXPORT_SYMBOL(kill_pid); | |
1713 | ||
1da177e4 LT |
1714 | /* |
1715 | * These functions support sending signals using preallocated sigqueue | |
1716 | * structures. This is needed "because realtime applications cannot | |
1717 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1718 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1719 | * we allocate the sigqueue structure from the timer_create. If this |
1720 | * allocation fails we are able to report the failure to the application | |
1721 | * with an EAGAIN error. | |
1722 | */ | |
1da177e4 LT |
1723 | struct sigqueue *sigqueue_alloc(void) |
1724 | { | |
f84d49b2 | 1725 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); |
1da177e4 | 1726 | |
f84d49b2 | 1727 | if (q) |
1da177e4 | 1728 | q->flags |= SIGQUEUE_PREALLOC; |
f84d49b2 NO |
1729 | |
1730 | return q; | |
1da177e4 LT |
1731 | } |
1732 | ||
1733 | void sigqueue_free(struct sigqueue *q) | |
1734 | { | |
1735 | unsigned long flags; | |
60187d27 ON |
1736 | spinlock_t *lock = ¤t->sighand->siglock; |
1737 | ||
1da177e4 LT |
1738 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1739 | /* | |
c8e85b4f ON |
1740 | * We must hold ->siglock while testing q->list |
1741 | * to serialize with collect_signal() or with | |
da7978b0 | 1742 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1743 | */ |
60187d27 | 1744 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1745 | q->flags &= ~SIGQUEUE_PREALLOC; |
1746 | /* | |
1747 | * If it is queued it will be freed when dequeued, | |
1748 | * like the "regular" sigqueue. | |
1749 | */ | |
60187d27 | 1750 | if (!list_empty(&q->list)) |
c8e85b4f | 1751 | q = NULL; |
60187d27 ON |
1752 | spin_unlock_irqrestore(lock, flags); |
1753 | ||
c8e85b4f ON |
1754 | if (q) |
1755 | __sigqueue_free(q); | |
1da177e4 LT |
1756 | } |
1757 | ||
24122c7f | 1758 | int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) |
9e3bd6c3 | 1759 | { |
e62e6650 | 1760 | int sig = q->info.si_signo; |
2ca3515a | 1761 | struct sigpending *pending; |
24122c7f | 1762 | struct task_struct *t; |
e62e6650 | 1763 | unsigned long flags; |
163566f6 | 1764 | int ret, result; |
2ca3515a | 1765 | |
4cd4b6d4 | 1766 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1767 | |
1768 | ret = -1; | |
24122c7f EB |
1769 | rcu_read_lock(); |
1770 | t = pid_task(pid, type); | |
1771 | if (!t || !likely(lock_task_sighand(t, &flags))) | |
e62e6650 ON |
1772 | goto ret; |
1773 | ||
7e695a5e | 1774 | ret = 1; /* the signal is ignored */ |
163566f6 | 1775 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1776 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1777 | goto out; |
1778 | ||
1779 | ret = 0; | |
9e3bd6c3 PE |
1780 | if (unlikely(!list_empty(&q->list))) { |
1781 | /* | |
1782 | * If an SI_TIMER entry is already queue just increment | |
1783 | * the overrun count. | |
1784 | */ | |
9e3bd6c3 PE |
1785 | BUG_ON(q->info.si_code != SI_TIMER); |
1786 | q->info.si_overrun++; | |
163566f6 | 1787 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1788 | goto out; |
9e3bd6c3 | 1789 | } |
ba661292 | 1790 | q->info.si_overrun = 0; |
9e3bd6c3 | 1791 | |
9e3bd6c3 | 1792 | signalfd_notify(t, sig); |
24122c7f | 1793 | pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1794 | list_add_tail(&q->list, &pending->list); |
1795 | sigaddset(&pending->signal, sig); | |
07296149 | 1796 | complete_signal(sig, t, type); |
163566f6 | 1797 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 1798 | out: |
24122c7f | 1799 | trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result); |
e62e6650 ON |
1800 | unlock_task_sighand(t, &flags); |
1801 | ret: | |
24122c7f | 1802 | rcu_read_unlock(); |
e62e6650 | 1803 | return ret; |
9e3bd6c3 PE |
1804 | } |
1805 | ||
1da177e4 LT |
1806 | /* |
1807 | * Let a parent know about the death of a child. | |
1808 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 1809 | * |
53c8f9f1 ON |
1810 | * Returns true if our parent ignored us and so we've switched to |
1811 | * self-reaping. | |
1da177e4 | 1812 | */ |
53c8f9f1 | 1813 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 | 1814 | { |
ae7795bc | 1815 | struct kernel_siginfo info; |
1da177e4 LT |
1816 | unsigned long flags; |
1817 | struct sighand_struct *psig; | |
53c8f9f1 | 1818 | bool autoreap = false; |
bde8285e | 1819 | u64 utime, stime; |
1da177e4 LT |
1820 | |
1821 | BUG_ON(sig == -1); | |
1822 | ||
1823 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1824 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 | 1825 | |
d21142ec | 1826 | BUG_ON(!tsk->ptrace && |
1da177e4 LT |
1827 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
1828 | ||
b6e238dc ON |
1829 | if (sig != SIGCHLD) { |
1830 | /* | |
1831 | * This is only possible if parent == real_parent. | |
1832 | * Check if it has changed security domain. | |
1833 | */ | |
1834 | if (tsk->parent_exec_id != tsk->parent->self_exec_id) | |
1835 | sig = SIGCHLD; | |
1836 | } | |
1837 | ||
faf1f22b | 1838 | clear_siginfo(&info); |
1da177e4 LT |
1839 | info.si_signo = sig; |
1840 | info.si_errno = 0; | |
b488893a | 1841 | /* |
32084504 EB |
1842 | * We are under tasklist_lock here so our parent is tied to |
1843 | * us and cannot change. | |
b488893a | 1844 | * |
32084504 EB |
1845 | * task_active_pid_ns will always return the same pid namespace |
1846 | * until a task passes through release_task. | |
b488893a PE |
1847 | * |
1848 | * write_lock() currently calls preempt_disable() which is the | |
1849 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1850 | * correct to rely on this | |
1851 | */ | |
1852 | rcu_read_lock(); | |
32084504 | 1853 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
1854 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
1855 | task_uid(tsk)); | |
b488893a PE |
1856 | rcu_read_unlock(); |
1857 | ||
bde8285e FW |
1858 | task_cputime(tsk, &utime, &stime); |
1859 | info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); | |
1860 | info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
1861 | |
1862 | info.si_status = tsk->exit_code & 0x7f; | |
1863 | if (tsk->exit_code & 0x80) | |
1864 | info.si_code = CLD_DUMPED; | |
1865 | else if (tsk->exit_code & 0x7f) | |
1866 | info.si_code = CLD_KILLED; | |
1867 | else { | |
1868 | info.si_code = CLD_EXITED; | |
1869 | info.si_status = tsk->exit_code >> 8; | |
1870 | } | |
1871 | ||
1872 | psig = tsk->parent->sighand; | |
1873 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 1874 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1875 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1876 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1877 | /* | |
1878 | * We are exiting and our parent doesn't care. POSIX.1 | |
1879 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1880 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1881 | * automatically and not left for our parent's wait4 call. | |
1882 | * Rather than having the parent do it as a magic kind of | |
1883 | * signal handler, we just set this to tell do_exit that we | |
1884 | * can be cleaned up without becoming a zombie. Note that | |
1885 | * we still call __wake_up_parent in this case, because a | |
1886 | * blocked sys_wait4 might now return -ECHILD. | |
1887 | * | |
1888 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1889 | * is implementation-defined: we do (if you don't want | |
1890 | * it, just use SIG_IGN instead). | |
1891 | */ | |
53c8f9f1 | 1892 | autoreap = true; |
1da177e4 | 1893 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 1894 | sig = 0; |
1da177e4 | 1895 | } |
53c8f9f1 | 1896 | if (valid_signal(sig) && sig) |
1da177e4 LT |
1897 | __group_send_sig_info(sig, &info, tsk->parent); |
1898 | __wake_up_parent(tsk, tsk->parent); | |
1899 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 1900 | |
53c8f9f1 | 1901 | return autoreap; |
1da177e4 LT |
1902 | } |
1903 | ||
75b95953 TH |
1904 | /** |
1905 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
1906 | * @tsk: task reporting the state change | |
1907 | * @for_ptracer: the notification is for ptracer | |
1908 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
1909 | * | |
1910 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
1911 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
1912 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
1913 | * | |
1914 | * CONTEXT: | |
1915 | * Must be called with tasklist_lock at least read locked. | |
1916 | */ | |
1917 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
1918 | bool for_ptracer, int why) | |
1da177e4 | 1919 | { |
ae7795bc | 1920 | struct kernel_siginfo info; |
1da177e4 | 1921 | unsigned long flags; |
bc505a47 | 1922 | struct task_struct *parent; |
1da177e4 | 1923 | struct sighand_struct *sighand; |
bde8285e | 1924 | u64 utime, stime; |
1da177e4 | 1925 | |
75b95953 | 1926 | if (for_ptracer) { |
bc505a47 | 1927 | parent = tsk->parent; |
75b95953 | 1928 | } else { |
bc505a47 ON |
1929 | tsk = tsk->group_leader; |
1930 | parent = tsk->real_parent; | |
1931 | } | |
1932 | ||
faf1f22b | 1933 | clear_siginfo(&info); |
1da177e4 LT |
1934 | info.si_signo = SIGCHLD; |
1935 | info.si_errno = 0; | |
b488893a | 1936 | /* |
5aba085e | 1937 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
1938 | */ |
1939 | rcu_read_lock(); | |
17cf22c3 | 1940 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 1941 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
1942 | rcu_read_unlock(); |
1943 | ||
bde8285e FW |
1944 | task_cputime(tsk, &utime, &stime); |
1945 | info.si_utime = nsec_to_clock_t(utime); | |
1946 | info.si_stime = nsec_to_clock_t(stime); | |
1da177e4 LT |
1947 | |
1948 | info.si_code = why; | |
1949 | switch (why) { | |
1950 | case CLD_CONTINUED: | |
1951 | info.si_status = SIGCONT; | |
1952 | break; | |
1953 | case CLD_STOPPED: | |
1954 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1955 | break; | |
1956 | case CLD_TRAPPED: | |
1957 | info.si_status = tsk->exit_code & 0x7f; | |
1958 | break; | |
1959 | default: | |
1960 | BUG(); | |
1961 | } | |
1962 | ||
1963 | sighand = parent->sighand; | |
1964 | spin_lock_irqsave(&sighand->siglock, flags); | |
1965 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1966 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1967 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1968 | /* | |
1969 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1970 | */ | |
1971 | __wake_up_parent(tsk, parent); | |
1972 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1973 | } | |
1974 | ||
6527de95 | 1975 | static inline bool may_ptrace_stop(void) |
d5f70c00 | 1976 | { |
d21142ec | 1977 | if (!likely(current->ptrace)) |
6527de95 | 1978 | return false; |
d5f70c00 ON |
1979 | /* |
1980 | * Are we in the middle of do_coredump? | |
1981 | * If so and our tracer is also part of the coredump stopping | |
1982 | * is a deadlock situation, and pointless because our tracer | |
1983 | * is dead so don't allow us to stop. | |
1984 | * If SIGKILL was already sent before the caller unlocked | |
999d9fc1 | 1985 | * ->siglock we must see ->core_state != NULL. Otherwise it |
d5f70c00 | 1986 | * is safe to enter schedule(). |
9899d11f ON |
1987 | * |
1988 | * This is almost outdated, a task with the pending SIGKILL can't | |
1989 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported | |
1990 | * after SIGKILL was already dequeued. | |
d5f70c00 | 1991 | */ |
999d9fc1 | 1992 | if (unlikely(current->mm->core_state) && |
d5f70c00 | 1993 | unlikely(current->mm == current->parent->mm)) |
6527de95 | 1994 | return false; |
d5f70c00 | 1995 | |
6527de95 | 1996 | return true; |
d5f70c00 ON |
1997 | } |
1998 | ||
1a669c2f | 1999 | /* |
5aba085e | 2000 | * Return non-zero if there is a SIGKILL that should be waking us up. |
1a669c2f RM |
2001 | * Called with the siglock held. |
2002 | */ | |
f99e9d8c | 2003 | static bool sigkill_pending(struct task_struct *tsk) |
1a669c2f | 2004 | { |
f99e9d8c CB |
2005 | return sigismember(&tsk->pending.signal, SIGKILL) || |
2006 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL); | |
1a669c2f RM |
2007 | } |
2008 | ||
1da177e4 LT |
2009 | /* |
2010 | * This must be called with current->sighand->siglock held. | |
2011 | * | |
2012 | * This should be the path for all ptrace stops. | |
2013 | * We always set current->last_siginfo while stopped here. | |
2014 | * That makes it a way to test a stopped process for | |
2015 | * being ptrace-stopped vs being job-control-stopped. | |
2016 | * | |
20686a30 ON |
2017 | * If we actually decide not to stop at all because the tracer |
2018 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 2019 | */ |
ae7795bc | 2020 | static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info) |
b8401150 NK |
2021 | __releases(¤t->sighand->siglock) |
2022 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 2023 | { |
ceb6bd67 TH |
2024 | bool gstop_done = false; |
2025 | ||
1a669c2f RM |
2026 | if (arch_ptrace_stop_needed(exit_code, info)) { |
2027 | /* | |
2028 | * The arch code has something special to do before a | |
2029 | * ptrace stop. This is allowed to block, e.g. for faults | |
2030 | * on user stack pages. We can't keep the siglock while | |
2031 | * calling arch_ptrace_stop, so we must release it now. | |
2032 | * To preserve proper semantics, we must do this before | |
2033 | * any signal bookkeeping like checking group_stop_count. | |
2034 | * Meanwhile, a SIGKILL could come in before we retake the | |
2035 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
2036 | * So after regaining the lock, we must check for SIGKILL. | |
2037 | */ | |
2038 | spin_unlock_irq(¤t->sighand->siglock); | |
2039 | arch_ptrace_stop(exit_code, info); | |
2040 | spin_lock_irq(¤t->sighand->siglock); | |
3d749b9e ON |
2041 | if (sigkill_pending(current)) |
2042 | return; | |
1a669c2f RM |
2043 | } |
2044 | ||
b5bf9a90 PZ |
2045 | set_special_state(TASK_TRACED); |
2046 | ||
1da177e4 | 2047 | /* |
81be24b8 TH |
2048 | * We're committing to trapping. TRACED should be visible before |
2049 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
2050 | * Also, transition to TRACED and updates to ->jobctl should be | |
2051 | * atomic with respect to siglock and should be done after the arch | |
2052 | * hook as siglock is released and regrabbed across it. | |
b5bf9a90 PZ |
2053 | * |
2054 | * TRACER TRACEE | |
2055 | * | |
2056 | * ptrace_attach() | |
2057 | * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED) | |
2058 | * do_wait() | |
2059 | * set_current_state() smp_wmb(); | |
2060 | * ptrace_do_wait() | |
2061 | * wait_task_stopped() | |
2062 | * task_stopped_code() | |
2063 | * [L] task_is_traced() [S] task_clear_jobctl_trapping(); | |
1da177e4 | 2064 | */ |
b5bf9a90 | 2065 | smp_wmb(); |
1da177e4 LT |
2066 | |
2067 | current->last_siginfo = info; | |
2068 | current->exit_code = exit_code; | |
2069 | ||
d79fdd6d | 2070 | /* |
0ae8ce1c TH |
2071 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
2072 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
2073 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
2074 | * could be clear now. We act as if SIGCONT is received after | |
2075 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 2076 | */ |
a8f072c1 | 2077 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 2078 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 2079 | |
fb1d910c | 2080 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 2081 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
2082 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
2083 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 2084 | |
81be24b8 | 2085 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 2086 | task_clear_jobctl_trapping(current); |
d79fdd6d | 2087 | |
1da177e4 LT |
2088 | spin_unlock_irq(¤t->sighand->siglock); |
2089 | read_lock(&tasklist_lock); | |
3d749b9e | 2090 | if (may_ptrace_stop()) { |
ceb6bd67 TH |
2091 | /* |
2092 | * Notify parents of the stop. | |
2093 | * | |
2094 | * While ptraced, there are two parents - the ptracer and | |
2095 | * the real_parent of the group_leader. The ptracer should | |
2096 | * know about every stop while the real parent is only | |
2097 | * interested in the completion of group stop. The states | |
2098 | * for the two don't interact with each other. Notify | |
2099 | * separately unless they're gonna be duplicates. | |
2100 | */ | |
2101 | do_notify_parent_cldstop(current, true, why); | |
bb3696da | 2102 | if (gstop_done && ptrace_reparented(current)) |
ceb6bd67 TH |
2103 | do_notify_parent_cldstop(current, false, why); |
2104 | ||
53da1d94 MS |
2105 | /* |
2106 | * Don't want to allow preemption here, because | |
2107 | * sys_ptrace() needs this task to be inactive. | |
2108 | * | |
2109 | * XXX: implement read_unlock_no_resched(). | |
2110 | */ | |
2111 | preempt_disable(); | |
1da177e4 | 2112 | read_unlock(&tasklist_lock); |
53da1d94 | 2113 | preempt_enable_no_resched(); |
76f969e8 | 2114 | cgroup_enter_frozen(); |
5d8f72b5 | 2115 | freezable_schedule(); |
05b28926 | 2116 | cgroup_leave_frozen(true); |
1da177e4 LT |
2117 | } else { |
2118 | /* | |
2119 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 2120 | * Don't drop the lock yet, another tracer may come. |
ceb6bd67 TH |
2121 | * |
2122 | * If @gstop_done, the ptracer went away between group stop | |
2123 | * completion and here. During detach, it would have set | |
a8f072c1 TH |
2124 | * JOBCTL_STOP_PENDING on us and we'll re-enter |
2125 | * TASK_STOPPED in do_signal_stop() on return, so notifying | |
2126 | * the real parent of the group stop completion is enough. | |
1da177e4 | 2127 | */ |
ceb6bd67 TH |
2128 | if (gstop_done) |
2129 | do_notify_parent_cldstop(current, false, why); | |
2130 | ||
9899d11f | 2131 | /* tasklist protects us from ptrace_freeze_traced() */ |
6405f7f4 | 2132 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
2133 | if (clear_code) |
2134 | current->exit_code = 0; | |
6405f7f4 | 2135 | read_unlock(&tasklist_lock); |
1da177e4 LT |
2136 | } |
2137 | ||
2138 | /* | |
2139 | * We are back. Now reacquire the siglock before touching | |
2140 | * last_siginfo, so that we are sure to have synchronized with | |
2141 | * any signal-sending on another CPU that wants to examine it. | |
2142 | */ | |
2143 | spin_lock_irq(¤t->sighand->siglock); | |
2144 | current->last_siginfo = NULL; | |
2145 | ||
544b2c91 TH |
2146 | /* LISTENING can be set only during STOP traps, clear it */ |
2147 | current->jobctl &= ~JOBCTL_LISTENING; | |
2148 | ||
1da177e4 LT |
2149 | /* |
2150 | * Queued signals ignored us while we were stopped for tracing. | |
2151 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 2152 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 2153 | */ |
b74d0deb | 2154 | recalc_sigpending_tsk(current); |
1da177e4 LT |
2155 | } |
2156 | ||
3544d72a | 2157 | static void ptrace_do_notify(int signr, int exit_code, int why) |
1da177e4 | 2158 | { |
ae7795bc | 2159 | kernel_siginfo_t info; |
1da177e4 | 2160 | |
faf1f22b | 2161 | clear_siginfo(&info); |
3544d72a | 2162 | info.si_signo = signr; |
1da177e4 | 2163 | info.si_code = exit_code; |
b488893a | 2164 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 2165 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2166 | |
2167 | /* Let the debugger run. */ | |
3544d72a TH |
2168 | ptrace_stop(exit_code, why, 1, &info); |
2169 | } | |
2170 | ||
2171 | void ptrace_notify(int exit_code) | |
2172 | { | |
2173 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
f784e8a7 ON |
2174 | if (unlikely(current->task_works)) |
2175 | task_work_run(); | |
3544d72a | 2176 | |
1da177e4 | 2177 | spin_lock_irq(¤t->sighand->siglock); |
3544d72a | 2178 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED); |
1da177e4 LT |
2179 | spin_unlock_irq(¤t->sighand->siglock); |
2180 | } | |
2181 | ||
73ddff2b TH |
2182 | /** |
2183 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
2184 | * @signr: signr causing group stop if initiating | |
2185 | * | |
2186 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
2187 | * and participate in it. If already set, participate in the existing | |
2188 | * group stop. If participated in a group stop (and thus slept), %true is | |
2189 | * returned with siglock released. | |
2190 | * | |
2191 | * If ptraced, this function doesn't handle stop itself. Instead, | |
2192 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
2193 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
2194 | * places afterwards. | |
2195 | * | |
2196 | * CONTEXT: | |
2197 | * Must be called with @current->sighand->siglock held, which is released | |
2198 | * on %true return. | |
2199 | * | |
2200 | * RETURNS: | |
2201 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
2202 | * %true if participated in group stop. | |
1da177e4 | 2203 | */ |
73ddff2b TH |
2204 | static bool do_signal_stop(int signr) |
2205 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
2206 | { |
2207 | struct signal_struct *sig = current->signal; | |
1da177e4 | 2208 | |
a8f072c1 | 2209 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
b76808e6 | 2210 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
f558b7e4 ON |
2211 | struct task_struct *t; |
2212 | ||
a8f072c1 TH |
2213 | /* signr will be recorded in task->jobctl for retries */ |
2214 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 2215 | |
a8f072c1 | 2216 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
573cf9ad | 2217 | unlikely(signal_group_exit(sig))) |
73ddff2b | 2218 | return false; |
1da177e4 | 2219 | /* |
408a37de TH |
2220 | * There is no group stop already in progress. We must |
2221 | * initiate one now. | |
2222 | * | |
2223 | * While ptraced, a task may be resumed while group stop is | |
2224 | * still in effect and then receive a stop signal and | |
2225 | * initiate another group stop. This deviates from the | |
2226 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2227 | * cause two group stops when !ptraced. That is why we |
2228 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2229 | * |
2230 | * The condition can be distinguished by testing whether | |
2231 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2232 | * group_exit_code in such case. | |
2233 | * | |
2234 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2235 | * an intervening stop signal is required to cause two | |
2236 | * continued events regardless of ptrace. | |
1da177e4 | 2237 | */ |
408a37de TH |
2238 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2239 | sig->group_exit_code = signr; | |
1da177e4 | 2240 | |
7dd3db54 TH |
2241 | sig->group_stop_count = 0; |
2242 | ||
2243 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2244 | sig->group_stop_count++; | |
1da177e4 | 2245 | |
8d38f203 ON |
2246 | t = current; |
2247 | while_each_thread(current, t) { | |
1da177e4 | 2248 | /* |
a122b341 ON |
2249 | * Setting state to TASK_STOPPED for a group |
2250 | * stop is always done with the siglock held, | |
2251 | * so this check has no races. | |
1da177e4 | 2252 | */ |
7dd3db54 TH |
2253 | if (!task_is_stopped(t) && |
2254 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2255 | sig->group_stop_count++; |
fb1d910c TH |
2256 | if (likely(!(t->ptrace & PT_SEIZED))) |
2257 | signal_wake_up(t, 0); | |
2258 | else | |
2259 | ptrace_trap_notify(t); | |
a122b341 | 2260 | } |
d79fdd6d | 2261 | } |
1da177e4 | 2262 | } |
73ddff2b | 2263 | |
d21142ec | 2264 | if (likely(!current->ptrace)) { |
5224fa36 | 2265 | int notify = 0; |
1da177e4 | 2266 | |
5224fa36 TH |
2267 | /* |
2268 | * If there are no other threads in the group, or if there | |
2269 | * is a group stop in progress and we are the last to stop, | |
2270 | * report to the parent. | |
2271 | */ | |
2272 | if (task_participate_group_stop(current)) | |
2273 | notify = CLD_STOPPED; | |
2274 | ||
b5bf9a90 | 2275 | set_special_state(TASK_STOPPED); |
5224fa36 TH |
2276 | spin_unlock_irq(¤t->sighand->siglock); |
2277 | ||
62bcf9d9 TH |
2278 | /* |
2279 | * Notify the parent of the group stop completion. Because | |
2280 | * we're not holding either the siglock or tasklist_lock | |
2281 | * here, ptracer may attach inbetween; however, this is for | |
2282 | * group stop and should always be delivered to the real | |
2283 | * parent of the group leader. The new ptracer will get | |
2284 | * its notification when this task transitions into | |
2285 | * TASK_TRACED. | |
2286 | */ | |
5224fa36 TH |
2287 | if (notify) { |
2288 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2289 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2290 | read_unlock(&tasklist_lock); |
2291 | } | |
2292 | ||
2293 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
76f969e8 | 2294 | cgroup_enter_frozen(); |
5d8f72b5 | 2295 | freezable_schedule(); |
73ddff2b | 2296 | return true; |
d79fdd6d | 2297 | } else { |
73ddff2b TH |
2298 | /* |
2299 | * While ptraced, group stop is handled by STOP trap. | |
2300 | * Schedule it and let the caller deal with it. | |
2301 | */ | |
2302 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2303 | return false; | |
ae6d2ed7 | 2304 | } |
73ddff2b | 2305 | } |
1da177e4 | 2306 | |
73ddff2b TH |
2307 | /** |
2308 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2309 | * | |
3544d72a TH |
2310 | * When PT_SEIZED, it's used for both group stop and explicit |
2311 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2312 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2313 | * the stop signal; otherwise, %SIGTRAP. | |
2314 | * | |
2315 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2316 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2317 | * |
2318 | * CONTEXT: | |
2319 | * Must be called with @current->sighand->siglock held, which may be | |
2320 | * released and re-acquired before returning with intervening sleep. | |
2321 | */ | |
2322 | static void do_jobctl_trap(void) | |
2323 | { | |
3544d72a | 2324 | struct signal_struct *signal = current->signal; |
73ddff2b | 2325 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2326 | |
3544d72a TH |
2327 | if (current->ptrace & PT_SEIZED) { |
2328 | if (!signal->group_stop_count && | |
2329 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2330 | signr = SIGTRAP; | |
2331 | WARN_ON_ONCE(!signr); | |
2332 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
2333 | CLD_STOPPED); | |
2334 | } else { | |
2335 | WARN_ON_ONCE(!signr); | |
2336 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); | |
2337 | current->exit_code = 0; | |
ae6d2ed7 | 2338 | } |
1da177e4 LT |
2339 | } |
2340 | ||
76f969e8 RG |
2341 | /** |
2342 | * do_freezer_trap - handle the freezer jobctl trap | |
2343 | * | |
2344 | * Puts the task into frozen state, if only the task is not about to quit. | |
2345 | * In this case it drops JOBCTL_TRAP_FREEZE. | |
2346 | * | |
2347 | * CONTEXT: | |
2348 | * Must be called with @current->sighand->siglock held, | |
2349 | * which is always released before returning. | |
2350 | */ | |
2351 | static void do_freezer_trap(void) | |
2352 | __releases(¤t->sighand->siglock) | |
2353 | { | |
2354 | /* | |
2355 | * If there are other trap bits pending except JOBCTL_TRAP_FREEZE, | |
2356 | * let's make another loop to give it a chance to be handled. | |
2357 | * In any case, we'll return back. | |
2358 | */ | |
2359 | if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) != | |
2360 | JOBCTL_TRAP_FREEZE) { | |
2361 | spin_unlock_irq(¤t->sighand->siglock); | |
2362 | return; | |
2363 | } | |
2364 | ||
2365 | /* | |
2366 | * Now we're sure that there is no pending fatal signal and no | |
2367 | * pending traps. Clear TIF_SIGPENDING to not get out of schedule() | |
2368 | * immediately (if there is a non-fatal signal pending), and | |
2369 | * put the task into sleep. | |
2370 | */ | |
2371 | __set_current_state(TASK_INTERRUPTIBLE); | |
2372 | clear_thread_flag(TIF_SIGPENDING); | |
2373 | spin_unlock_irq(¤t->sighand->siglock); | |
2374 | cgroup_enter_frozen(); | |
2375 | freezable_schedule(); | |
2376 | } | |
2377 | ||
ae7795bc | 2378 | static int ptrace_signal(int signr, kernel_siginfo_t *info) |
18c98b65 | 2379 | { |
8a352418 ON |
2380 | /* |
2381 | * We do not check sig_kernel_stop(signr) but set this marker | |
2382 | * unconditionally because we do not know whether debugger will | |
2383 | * change signr. This flag has no meaning unless we are going | |
2384 | * to stop after return from ptrace_stop(). In this case it will | |
2385 | * be checked in do_signal_stop(), we should only stop if it was | |
2386 | * not cleared by SIGCONT while we were sleeping. See also the | |
2387 | * comment in dequeue_signal(). | |
2388 | */ | |
2389 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
fe1bc6a0 | 2390 | ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2391 | |
2392 | /* We're back. Did the debugger cancel the sig? */ | |
2393 | signr = current->exit_code; | |
2394 | if (signr == 0) | |
2395 | return signr; | |
2396 | ||
2397 | current->exit_code = 0; | |
2398 | ||
5aba085e RD |
2399 | /* |
2400 | * Update the siginfo structure if the signal has | |
2401 | * changed. If the debugger wanted something | |
2402 | * specific in the siginfo structure then it should | |
2403 | * have updated *info via PTRACE_SETSIGINFO. | |
2404 | */ | |
18c98b65 | 2405 | if (signr != info->si_signo) { |
faf1f22b | 2406 | clear_siginfo(info); |
18c98b65 RM |
2407 | info->si_signo = signr; |
2408 | info->si_errno = 0; | |
2409 | info->si_code = SI_USER; | |
6b550f94 | 2410 | rcu_read_lock(); |
18c98b65 | 2411 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2412 | info->si_uid = from_kuid_munged(current_user_ns(), |
2413 | task_uid(current->parent)); | |
6b550f94 | 2414 | rcu_read_unlock(); |
18c98b65 RM |
2415 | } |
2416 | ||
2417 | /* If the (new) signal is now blocked, requeue it. */ | |
2418 | if (sigismember(¤t->blocked, signr)) { | |
b21c5bd5 | 2419 | send_signal(signr, info, current, PIDTYPE_PID); |
18c98b65 RM |
2420 | signr = 0; |
2421 | } | |
2422 | ||
2423 | return signr; | |
2424 | } | |
2425 | ||
20ab7218 | 2426 | bool get_signal(struct ksignal *ksig) |
1da177e4 | 2427 | { |
f6b76d4f ON |
2428 | struct sighand_struct *sighand = current->sighand; |
2429 | struct signal_struct *signal = current->signal; | |
2430 | int signr; | |
1da177e4 | 2431 | |
f784e8a7 ON |
2432 | if (unlikely(current->task_works)) |
2433 | task_work_run(); | |
72667028 | 2434 | |
0326f5a9 | 2435 | if (unlikely(uprobe_deny_signal())) |
20ab7218 | 2436 | return false; |
0326f5a9 | 2437 | |
13b1c3d4 | 2438 | /* |
5d8f72b5 ON |
2439 | * Do this once, we can't return to user-mode if freezing() == T. |
2440 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2441 | * thus do not need another check after return. | |
13b1c3d4 | 2442 | */ |
fc558a74 RW |
2443 | try_to_freeze(); |
2444 | ||
5d8f72b5 | 2445 | relock: |
f6b76d4f | 2446 | spin_lock_irq(&sighand->siglock); |
021e1ae3 ON |
2447 | /* |
2448 | * Every stopped thread goes here after wakeup. Check to see if | |
2449 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2450 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2451 | */ | |
f6b76d4f | 2452 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2453 | int why; |
2454 | ||
2455 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2456 | why = CLD_CONTINUED; | |
2457 | else | |
2458 | why = CLD_STOPPED; | |
2459 | ||
f6b76d4f | 2460 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2461 | |
ae6d2ed7 | 2462 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2463 | |
ceb6bd67 TH |
2464 | /* |
2465 | * Notify the parent that we're continuing. This event is | |
2466 | * always per-process and doesn't make whole lot of sense | |
2467 | * for ptracers, who shouldn't consume the state via | |
2468 | * wait(2) either, but, for backward compatibility, notify | |
2469 | * the ptracer of the group leader too unless it's gonna be | |
2470 | * a duplicate. | |
2471 | */ | |
edf2ed15 | 2472 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2473 | do_notify_parent_cldstop(current, false, why); |
2474 | ||
bb3696da ON |
2475 | if (ptrace_reparented(current->group_leader)) |
2476 | do_notify_parent_cldstop(current->group_leader, | |
2477 | true, why); | |
edf2ed15 | 2478 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2479 | |
e4420551 ON |
2480 | goto relock; |
2481 | } | |
2482 | ||
35634ffa | 2483 | /* Has this task already been marked for death? */ |
cf43a757 EB |
2484 | if (signal_group_exit(signal)) { |
2485 | ksig->info.si_signo = signr = SIGKILL; | |
2486 | sigdelset(¤t->pending.signal, SIGKILL); | |
2487 | recalc_sigpending(); | |
35634ffa | 2488 | goto fatal; |
cf43a757 | 2489 | } |
35634ffa | 2490 | |
1da177e4 LT |
2491 | for (;;) { |
2492 | struct k_sigaction *ka; | |
1be53963 | 2493 | |
dd1d6772 TH |
2494 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2495 | do_signal_stop(0)) | |
7bcf6a2c | 2496 | goto relock; |
1be53963 | 2497 | |
76f969e8 RG |
2498 | if (unlikely(current->jobctl & |
2499 | (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) { | |
2500 | if (current->jobctl & JOBCTL_TRAP_MASK) { | |
2501 | do_jobctl_trap(); | |
2502 | spin_unlock_irq(&sighand->siglock); | |
2503 | } else if (current->jobctl & JOBCTL_TRAP_FREEZE) | |
2504 | do_freezer_trap(); | |
2505 | ||
2506 | goto relock; | |
2507 | } | |
2508 | ||
2509 | /* | |
2510 | * If the task is leaving the frozen state, let's update | |
2511 | * cgroup counters and reset the frozen bit. | |
2512 | */ | |
2513 | if (unlikely(cgroup_task_frozen(current))) { | |
73ddff2b | 2514 | spin_unlock_irq(&sighand->siglock); |
cb2c4cd8 | 2515 | cgroup_leave_frozen(false); |
73ddff2b TH |
2516 | goto relock; |
2517 | } | |
1da177e4 | 2518 | |
7146db33 EB |
2519 | /* |
2520 | * Signals generated by the execution of an instruction | |
2521 | * need to be delivered before any other pending signals | |
2522 | * so that the instruction pointer in the signal stack | |
2523 | * frame points to the faulting instruction. | |
2524 | */ | |
2525 | signr = dequeue_synchronous_signal(&ksig->info); | |
2526 | if (!signr) | |
2527 | signr = dequeue_signal(current, ¤t->blocked, &ksig->info); | |
7bcf6a2c | 2528 | |
dd1d6772 TH |
2529 | if (!signr) |
2530 | break; /* will return 0 */ | |
7bcf6a2c | 2531 | |
8a352418 | 2532 | if (unlikely(current->ptrace) && signr != SIGKILL) { |
828b1f65 | 2533 | signr = ptrace_signal(signr, &ksig->info); |
dd1d6772 TH |
2534 | if (!signr) |
2535 | continue; | |
1da177e4 LT |
2536 | } |
2537 | ||
dd1d6772 TH |
2538 | ka = &sighand->action[signr-1]; |
2539 | ||
f9d4257e | 2540 | /* Trace actually delivered signals. */ |
828b1f65 | 2541 | trace_signal_deliver(signr, &ksig->info, ka); |
f9d4257e | 2542 | |
1da177e4 LT |
2543 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2544 | continue; | |
2545 | if (ka->sa.sa_handler != SIG_DFL) { | |
2546 | /* Run the handler. */ | |
828b1f65 | 2547 | ksig->ka = *ka; |
1da177e4 LT |
2548 | |
2549 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2550 | ka->sa.sa_handler = SIG_DFL; | |
2551 | ||
2552 | break; /* will return non-zero "signr" value */ | |
2553 | } | |
2554 | ||
2555 | /* | |
2556 | * Now we are doing the default action for this signal. | |
2557 | */ | |
2558 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2559 | continue; | |
2560 | ||
84d73786 | 2561 | /* |
0fbc26a6 | 2562 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2563 | * Container-init gets no signals it doesn't want from same |
2564 | * container. | |
2565 | * | |
2566 | * Note that if global/container-init sees a sig_kernel_only() | |
2567 | * signal here, the signal must have been generated internally | |
2568 | * or must have come from an ancestor namespace. In either | |
2569 | * case, the signal cannot be dropped. | |
84d73786 | 2570 | */ |
fae5fa44 | 2571 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2572 | !sig_kernel_only(signr)) |
1da177e4 LT |
2573 | continue; |
2574 | ||
2575 | if (sig_kernel_stop(signr)) { | |
2576 | /* | |
2577 | * The default action is to stop all threads in | |
2578 | * the thread group. The job control signals | |
2579 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2580 | * always works. Note that siglock needs to be | |
2581 | * dropped during the call to is_orphaned_pgrp() | |
2582 | * because of lock ordering with tasklist_lock. | |
2583 | * This allows an intervening SIGCONT to be posted. | |
2584 | * We need to check for that and bail out if necessary. | |
2585 | */ | |
2586 | if (signr != SIGSTOP) { | |
f6b76d4f | 2587 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2588 | |
2589 | /* signals can be posted during this window */ | |
2590 | ||
3e7cd6c4 | 2591 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2592 | goto relock; |
2593 | ||
f6b76d4f | 2594 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2595 | } |
2596 | ||
828b1f65 | 2597 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
1da177e4 LT |
2598 | /* It released the siglock. */ |
2599 | goto relock; | |
2600 | } | |
2601 | ||
2602 | /* | |
2603 | * We didn't actually stop, due to a race | |
2604 | * with SIGCONT or something like that. | |
2605 | */ | |
2606 | continue; | |
2607 | } | |
2608 | ||
35634ffa | 2609 | fatal: |
f6b76d4f | 2610 | spin_unlock_irq(&sighand->siglock); |
f2b31bb5 RG |
2611 | if (unlikely(cgroup_task_frozen(current))) |
2612 | cgroup_leave_frozen(true); | |
1da177e4 LT |
2613 | |
2614 | /* | |
2615 | * Anything else is fatal, maybe with a core dump. | |
2616 | */ | |
2617 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2618 | |
1da177e4 | 2619 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2620 | if (print_fatal_signals) |
828b1f65 | 2621 | print_fatal_signal(ksig->info.si_signo); |
2b5faa4c | 2622 | proc_coredump_connector(current); |
1da177e4 LT |
2623 | /* |
2624 | * If it was able to dump core, this kills all | |
2625 | * other threads in the group and synchronizes with | |
2626 | * their demise. If we lost the race with another | |
2627 | * thread getting here, it set group_exit_code | |
2628 | * first and our do_group_exit call below will use | |
2629 | * that value and ignore the one we pass it. | |
2630 | */ | |
828b1f65 | 2631 | do_coredump(&ksig->info); |
1da177e4 LT |
2632 | } |
2633 | ||
2634 | /* | |
2635 | * Death signals, no core dump. | |
2636 | */ | |
828b1f65 | 2637 | do_group_exit(ksig->info.si_signo); |
1da177e4 LT |
2638 | /* NOTREACHED */ |
2639 | } | |
f6b76d4f | 2640 | spin_unlock_irq(&sighand->siglock); |
828b1f65 RW |
2641 | |
2642 | ksig->sig = signr; | |
2643 | return ksig->sig > 0; | |
1da177e4 LT |
2644 | } |
2645 | ||
5e6292c0 | 2646 | /** |
efee984c | 2647 | * signal_delivered - |
10b1c7ac | 2648 | * @ksig: kernel signal struct |
efee984c | 2649 | * @stepping: nonzero if debugger single-step or block-step in use |
5e6292c0 | 2650 | * |
e227867f | 2651 | * This function should be called when a signal has successfully been |
10b1c7ac | 2652 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
efee984c | 2653 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER |
10b1c7ac | 2654 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
5e6292c0 | 2655 | */ |
10b1c7ac | 2656 | static void signal_delivered(struct ksignal *ksig, int stepping) |
5e6292c0 MF |
2657 | { |
2658 | sigset_t blocked; | |
2659 | ||
a610d6e6 AV |
2660 | /* A signal was successfully delivered, and the |
2661 | saved sigmask was stored on the signal frame, | |
2662 | and will be restored by sigreturn. So we can | |
2663 | simply clear the restore sigmask flag. */ | |
2664 | clear_restore_sigmask(); | |
2665 | ||
10b1c7ac RW |
2666 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
2667 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) | |
2668 | sigaddset(&blocked, ksig->sig); | |
5e6292c0 | 2669 | set_current_blocked(&blocked); |
df5601f9 | 2670 | tracehook_signal_handler(stepping); |
5e6292c0 MF |
2671 | } |
2672 | ||
2ce5da17 AV |
2673 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2674 | { | |
2675 | if (failed) | |
2676 | force_sigsegv(ksig->sig, current); | |
2677 | else | |
10b1c7ac | 2678 | signal_delivered(ksig, stepping); |
2ce5da17 AV |
2679 | } |
2680 | ||
0edceb7b ON |
2681 | /* |
2682 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2683 | * group-wide signal. Other threads should be notified now to take |
2684 | * the shared signals in @which since we will not. | |
0edceb7b | 2685 | */ |
f646e227 | 2686 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2687 | { |
f646e227 | 2688 | sigset_t retarget; |
0edceb7b ON |
2689 | struct task_struct *t; |
2690 | ||
f646e227 ON |
2691 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2692 | if (sigisemptyset(&retarget)) | |
2693 | return; | |
2694 | ||
0edceb7b ON |
2695 | t = tsk; |
2696 | while_each_thread(tsk, t) { | |
fec9993d ON |
2697 | if (t->flags & PF_EXITING) |
2698 | continue; | |
2699 | ||
2700 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2701 | continue; | |
2702 | /* Remove the signals this thread can handle. */ | |
2703 | sigandsets(&retarget, &retarget, &t->blocked); | |
2704 | ||
2705 | if (!signal_pending(t)) | |
2706 | signal_wake_up(t, 0); | |
2707 | ||
2708 | if (sigisemptyset(&retarget)) | |
2709 | break; | |
0edceb7b ON |
2710 | } |
2711 | } | |
2712 | ||
d12619b5 ON |
2713 | void exit_signals(struct task_struct *tsk) |
2714 | { | |
2715 | int group_stop = 0; | |
f646e227 | 2716 | sigset_t unblocked; |
d12619b5 | 2717 | |
77e4ef99 TH |
2718 | /* |
2719 | * @tsk is about to have PF_EXITING set - lock out users which | |
2720 | * expect stable threadgroup. | |
2721 | */ | |
780de9dd | 2722 | cgroup_threadgroup_change_begin(tsk); |
77e4ef99 | 2723 | |
5dee1707 ON |
2724 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
2725 | tsk->flags |= PF_EXITING; | |
780de9dd | 2726 | cgroup_threadgroup_change_end(tsk); |
5dee1707 | 2727 | return; |
d12619b5 ON |
2728 | } |
2729 | ||
5dee1707 | 2730 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2731 | /* |
2732 | * From now this task is not visible for group-wide signals, | |
2733 | * see wants_signal(), do_signal_stop(). | |
2734 | */ | |
2735 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2736 | |
780de9dd | 2737 | cgroup_threadgroup_change_end(tsk); |
77e4ef99 | 2738 | |
5dee1707 ON |
2739 | if (!signal_pending(tsk)) |
2740 | goto out; | |
2741 | ||
f646e227 ON |
2742 | unblocked = tsk->blocked; |
2743 | signotset(&unblocked); | |
2744 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2745 | |
a8f072c1 | 2746 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2747 | task_participate_group_stop(tsk)) |
edf2ed15 | 2748 | group_stop = CLD_STOPPED; |
5dee1707 | 2749 | out: |
d12619b5 ON |
2750 | spin_unlock_irq(&tsk->sighand->siglock); |
2751 | ||
62bcf9d9 TH |
2752 | /* |
2753 | * If group stop has completed, deliver the notification. This | |
2754 | * should always go to the real parent of the group leader. | |
2755 | */ | |
ae6d2ed7 | 2756 | if (unlikely(group_stop)) { |
d12619b5 | 2757 | read_lock(&tasklist_lock); |
62bcf9d9 | 2758 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2759 | read_unlock(&tasklist_lock); |
2760 | } | |
2761 | } | |
2762 | ||
1da177e4 LT |
2763 | /* |
2764 | * System call entry points. | |
2765 | */ | |
2766 | ||
41c57892 RD |
2767 | /** |
2768 | * sys_restart_syscall - restart a system call | |
2769 | */ | |
754fe8d2 | 2770 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 | 2771 | { |
f56141e3 | 2772 | struct restart_block *restart = ¤t->restart_block; |
1da177e4 LT |
2773 | return restart->fn(restart); |
2774 | } | |
2775 | ||
2776 | long do_no_restart_syscall(struct restart_block *param) | |
2777 | { | |
2778 | return -EINTR; | |
2779 | } | |
2780 | ||
b182801a ON |
2781 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
2782 | { | |
2783 | if (signal_pending(tsk) && !thread_group_empty(tsk)) { | |
2784 | sigset_t newblocked; | |
2785 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 2786 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
2787 | retarget_shared_pending(tsk, &newblocked); |
2788 | } | |
2789 | tsk->blocked = *newset; | |
2790 | recalc_sigpending(); | |
2791 | } | |
2792 | ||
e6fa16ab ON |
2793 | /** |
2794 | * set_current_blocked - change current->blocked mask | |
2795 | * @newset: new mask | |
2796 | * | |
2797 | * It is wrong to change ->blocked directly, this helper should be used | |
2798 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 2799 | */ |
77097ae5 AV |
2800 | void set_current_blocked(sigset_t *newset) |
2801 | { | |
77097ae5 | 2802 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 2803 | __set_current_blocked(newset); |
77097ae5 AV |
2804 | } |
2805 | ||
2806 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
2807 | { |
2808 | struct task_struct *tsk = current; | |
2809 | ||
c7be96af WL |
2810 | /* |
2811 | * In case the signal mask hasn't changed, there is nothing we need | |
2812 | * to do. The current->blocked shouldn't be modified by other task. | |
2813 | */ | |
2814 | if (sigequalsets(&tsk->blocked, newset)) | |
2815 | return; | |
2816 | ||
e6fa16ab | 2817 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 2818 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
2819 | spin_unlock_irq(&tsk->sighand->siglock); |
2820 | } | |
1da177e4 LT |
2821 | |
2822 | /* | |
2823 | * This is also useful for kernel threads that want to temporarily | |
2824 | * (or permanently) block certain signals. | |
2825 | * | |
2826 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2827 | * interface happily blocks "unblockable" signals like SIGKILL | |
2828 | * and friends. | |
2829 | */ | |
2830 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2831 | { | |
73ef4aeb ON |
2832 | struct task_struct *tsk = current; |
2833 | sigset_t newset; | |
1da177e4 | 2834 | |
73ef4aeb | 2835 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 2836 | if (oldset) |
73ef4aeb | 2837 | *oldset = tsk->blocked; |
a26fd335 | 2838 | |
1da177e4 LT |
2839 | switch (how) { |
2840 | case SIG_BLOCK: | |
73ef4aeb | 2841 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2842 | break; |
2843 | case SIG_UNBLOCK: | |
702a5073 | 2844 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
2845 | break; |
2846 | case SIG_SETMASK: | |
73ef4aeb | 2847 | newset = *set; |
1da177e4 LT |
2848 | break; |
2849 | default: | |
73ef4aeb | 2850 | return -EINVAL; |
1da177e4 | 2851 | } |
a26fd335 | 2852 | |
77097ae5 | 2853 | __set_current_blocked(&newset); |
73ef4aeb | 2854 | return 0; |
1da177e4 | 2855 | } |
fb50f5a4 | 2856 | EXPORT_SYMBOL(sigprocmask); |
1da177e4 | 2857 | |
ded653cc DD |
2858 | /* |
2859 | * The api helps set app-provided sigmasks. | |
2860 | * | |
2861 | * This is useful for syscalls such as ppoll, pselect, io_pgetevents and | |
2862 | * epoll_pwait where a new sigmask is passed from userland for the syscalls. | |
2863 | */ | |
2864 | int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set, | |
2865 | sigset_t *oldset, size_t sigsetsize) | |
2866 | { | |
2867 | if (!usigmask) | |
2868 | return 0; | |
2869 | ||
2870 | if (sigsetsize != sizeof(sigset_t)) | |
2871 | return -EINVAL; | |
2872 | if (copy_from_user(set, usigmask, sizeof(sigset_t))) | |
2873 | return -EFAULT; | |
2874 | ||
2875 | *oldset = current->blocked; | |
2876 | set_current_blocked(set); | |
2877 | ||
2878 | return 0; | |
2879 | } | |
2880 | EXPORT_SYMBOL(set_user_sigmask); | |
2881 | ||
2882 | #ifdef CONFIG_COMPAT | |
2883 | int set_compat_user_sigmask(const compat_sigset_t __user *usigmask, | |
2884 | sigset_t *set, sigset_t *oldset, | |
2885 | size_t sigsetsize) | |
2886 | { | |
2887 | if (!usigmask) | |
2888 | return 0; | |
2889 | ||
2890 | if (sigsetsize != sizeof(compat_sigset_t)) | |
2891 | return -EINVAL; | |
2892 | if (get_compat_sigset(set, usigmask)) | |
2893 | return -EFAULT; | |
2894 | ||
2895 | *oldset = current->blocked; | |
2896 | set_current_blocked(set); | |
2897 | ||
2898 | return 0; | |
2899 | } | |
2900 | EXPORT_SYMBOL(set_compat_user_sigmask); | |
2901 | #endif | |
2902 | ||
854a6ed5 DD |
2903 | /* |
2904 | * restore_user_sigmask: | |
2905 | * usigmask: sigmask passed in from userland. | |
2906 | * sigsaved: saved sigmask when the syscall started and changed the sigmask to | |
2907 | * usigmask. | |
2908 | * | |
2909 | * This is useful for syscalls such as ppoll, pselect, io_pgetevents and | |
2910 | * epoll_pwait where a new sigmask is passed in from userland for the syscalls. | |
2911 | */ | |
2912 | void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved) | |
2913 | { | |
2914 | ||
2915 | if (!usigmask) | |
2916 | return; | |
2917 | /* | |
2918 | * When signals are pending, do not restore them here. | |
2919 | * Restoring sigmask here can lead to delivering signals that the above | |
2920 | * syscalls are intended to block because of the sigmask passed in. | |
2921 | */ | |
2922 | if (signal_pending(current)) { | |
2923 | current->saved_sigmask = *sigsaved; | |
2924 | set_restore_sigmask(); | |
2925 | return; | |
2926 | } | |
2927 | ||
2928 | /* | |
2929 | * This is needed because the fast syscall return path does not restore | |
2930 | * saved_sigmask when signals are not pending. | |
2931 | */ | |
2932 | set_current_blocked(sigsaved); | |
2933 | } | |
2934 | EXPORT_SYMBOL(restore_user_sigmask); | |
2935 | ||
41c57892 RD |
2936 | /** |
2937 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
2938 | * @how: whether to add, remove, or set signals | |
ada9c933 | 2939 | * @nset: stores pending signals |
41c57892 RD |
2940 | * @oset: previous value of signal mask if non-null |
2941 | * @sigsetsize: size of sigset_t type | |
2942 | */ | |
bb7efee2 | 2943 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 2944 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 2945 | { |
1da177e4 | 2946 | sigset_t old_set, new_set; |
bb7efee2 | 2947 | int error; |
1da177e4 LT |
2948 | |
2949 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2950 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 2951 | return -EINVAL; |
1da177e4 | 2952 | |
bb7efee2 ON |
2953 | old_set = current->blocked; |
2954 | ||
2955 | if (nset) { | |
2956 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
2957 | return -EFAULT; | |
1da177e4 LT |
2958 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2959 | ||
bb7efee2 | 2960 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 2961 | if (error) |
bb7efee2 ON |
2962 | return error; |
2963 | } | |
1da177e4 | 2964 | |
bb7efee2 ON |
2965 | if (oset) { |
2966 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
2967 | return -EFAULT; | |
1da177e4 | 2968 | } |
bb7efee2 ON |
2969 | |
2970 | return 0; | |
1da177e4 LT |
2971 | } |
2972 | ||
322a56cb | 2973 | #ifdef CONFIG_COMPAT |
322a56cb AV |
2974 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
2975 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 2976 | { |
322a56cb AV |
2977 | sigset_t old_set = current->blocked; |
2978 | ||
2979 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2980 | if (sigsetsize != sizeof(sigset_t)) | |
2981 | return -EINVAL; | |
2982 | ||
2983 | if (nset) { | |
322a56cb AV |
2984 | sigset_t new_set; |
2985 | int error; | |
3968cf62 | 2986 | if (get_compat_sigset(&new_set, nset)) |
322a56cb | 2987 | return -EFAULT; |
322a56cb AV |
2988 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2989 | ||
2990 | error = sigprocmask(how, &new_set, NULL); | |
2991 | if (error) | |
2992 | return error; | |
2993 | } | |
f454322e | 2994 | return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; |
322a56cb AV |
2995 | } |
2996 | #endif | |
1da177e4 | 2997 | |
b1d294c8 | 2998 | static void do_sigpending(sigset_t *set) |
1da177e4 | 2999 | { |
1da177e4 | 3000 | spin_lock_irq(¤t->sighand->siglock); |
fe9c1db2 | 3001 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
3002 | ¤t->signal->shared_pending.signal); |
3003 | spin_unlock_irq(¤t->sighand->siglock); | |
3004 | ||
3005 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 | 3006 | sigandsets(set, ¤t->blocked, set); |
5aba085e | 3007 | } |
1da177e4 | 3008 | |
41c57892 RD |
3009 | /** |
3010 | * sys_rt_sigpending - examine a pending signal that has been raised | |
3011 | * while blocked | |
20f22ab4 | 3012 | * @uset: stores pending signals |
41c57892 RD |
3013 | * @sigsetsize: size of sigset_t type or larger |
3014 | */ | |
fe9c1db2 | 3015 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 3016 | { |
fe9c1db2 | 3017 | sigset_t set; |
176826af DL |
3018 | |
3019 | if (sigsetsize > sizeof(*uset)) | |
3020 | return -EINVAL; | |
3021 | ||
b1d294c8 CB |
3022 | do_sigpending(&set); |
3023 | ||
3024 | if (copy_to_user(uset, &set, sigsetsize)) | |
3025 | return -EFAULT; | |
3026 | ||
3027 | return 0; | |
fe9c1db2 AV |
3028 | } |
3029 | ||
3030 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
3031 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
3032 | compat_size_t, sigsetsize) | |
1da177e4 | 3033 | { |
fe9c1db2 | 3034 | sigset_t set; |
176826af DL |
3035 | |
3036 | if (sigsetsize > sizeof(*uset)) | |
3037 | return -EINVAL; | |
3038 | ||
b1d294c8 CB |
3039 | do_sigpending(&set); |
3040 | ||
3041 | return put_compat_sigset(uset, &set, sigsetsize); | |
1da177e4 | 3042 | } |
fe9c1db2 | 3043 | #endif |
1da177e4 | 3044 | |
4ce5f9c9 EB |
3045 | static const struct { |
3046 | unsigned char limit, layout; | |
3047 | } sig_sicodes[] = { | |
3048 | [SIGILL] = { NSIGILL, SIL_FAULT }, | |
3049 | [SIGFPE] = { NSIGFPE, SIL_FAULT }, | |
3050 | [SIGSEGV] = { NSIGSEGV, SIL_FAULT }, | |
3051 | [SIGBUS] = { NSIGBUS, SIL_FAULT }, | |
3052 | [SIGTRAP] = { NSIGTRAP, SIL_FAULT }, | |
3053 | #if defined(SIGEMT) | |
3054 | [SIGEMT] = { NSIGEMT, SIL_FAULT }, | |
3055 | #endif | |
3056 | [SIGCHLD] = { NSIGCHLD, SIL_CHLD }, | |
3057 | [SIGPOLL] = { NSIGPOLL, SIL_POLL }, | |
3058 | [SIGSYS] = { NSIGSYS, SIL_SYS }, | |
3059 | }; | |
3060 | ||
b2a2ab52 | 3061 | static bool known_siginfo_layout(unsigned sig, int si_code) |
4ce5f9c9 EB |
3062 | { |
3063 | if (si_code == SI_KERNEL) | |
3064 | return true; | |
3065 | else if ((si_code > SI_USER)) { | |
3066 | if (sig_specific_sicodes(sig)) { | |
3067 | if (si_code <= sig_sicodes[sig].limit) | |
3068 | return true; | |
3069 | } | |
3070 | else if (si_code <= NSIGPOLL) | |
3071 | return true; | |
3072 | } | |
3073 | else if (si_code >= SI_DETHREAD) | |
3074 | return true; | |
3075 | else if (si_code == SI_ASYNCNL) | |
3076 | return true; | |
3077 | return false; | |
3078 | } | |
3079 | ||
a3670058 | 3080 | enum siginfo_layout siginfo_layout(unsigned sig, int si_code) |
cc731525 EB |
3081 | { |
3082 | enum siginfo_layout layout = SIL_KILL; | |
3083 | if ((si_code > SI_USER) && (si_code < SI_KERNEL)) { | |
4ce5f9c9 EB |
3084 | if ((sig < ARRAY_SIZE(sig_sicodes)) && |
3085 | (si_code <= sig_sicodes[sig].limit)) { | |
3086 | layout = sig_sicodes[sig].layout; | |
31931c93 EB |
3087 | /* Handle the exceptions */ |
3088 | if ((sig == SIGBUS) && | |
3089 | (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO)) | |
3090 | layout = SIL_FAULT_MCEERR; | |
3091 | else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR)) | |
3092 | layout = SIL_FAULT_BNDERR; | |
3093 | #ifdef SEGV_PKUERR | |
3094 | else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR)) | |
3095 | layout = SIL_FAULT_PKUERR; | |
3096 | #endif | |
3097 | } | |
cc731525 EB |
3098 | else if (si_code <= NSIGPOLL) |
3099 | layout = SIL_POLL; | |
3100 | } else { | |
3101 | if (si_code == SI_TIMER) | |
3102 | layout = SIL_TIMER; | |
3103 | else if (si_code == SI_SIGIO) | |
3104 | layout = SIL_POLL; | |
3105 | else if (si_code < 0) | |
3106 | layout = SIL_RT; | |
cc731525 EB |
3107 | } |
3108 | return layout; | |
3109 | } | |
3110 | ||
4ce5f9c9 EB |
3111 | static inline char __user *si_expansion(const siginfo_t __user *info) |
3112 | { | |
3113 | return ((char __user *)info) + sizeof(struct kernel_siginfo); | |
3114 | } | |
3115 | ||
ae7795bc | 3116 | int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from) |
1da177e4 | 3117 | { |
4ce5f9c9 | 3118 | char __user *expansion = si_expansion(to); |
ae7795bc | 3119 | if (copy_to_user(to, from , sizeof(struct kernel_siginfo))) |
1da177e4 | 3120 | return -EFAULT; |
4ce5f9c9 | 3121 | if (clear_user(expansion, SI_EXPANSION_SIZE)) |
1da177e4 | 3122 | return -EFAULT; |
c999b933 | 3123 | return 0; |
1da177e4 LT |
3124 | } |
3125 | ||
601d5abf EB |
3126 | static int post_copy_siginfo_from_user(kernel_siginfo_t *info, |
3127 | const siginfo_t __user *from) | |
4cd2e0e7 | 3128 | { |
601d5abf | 3129 | if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) { |
4ce5f9c9 EB |
3130 | char __user *expansion = si_expansion(from); |
3131 | char buf[SI_EXPANSION_SIZE]; | |
3132 | int i; | |
3133 | /* | |
3134 | * An unknown si_code might need more than | |
3135 | * sizeof(struct kernel_siginfo) bytes. Verify all of the | |
3136 | * extra bytes are 0. This guarantees copy_siginfo_to_user | |
3137 | * will return this data to userspace exactly. | |
3138 | */ | |
3139 | if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE)) | |
3140 | return -EFAULT; | |
3141 | for (i = 0; i < SI_EXPANSION_SIZE; i++) { | |
3142 | if (buf[i] != 0) | |
3143 | return -E2BIG; | |
3144 | } | |
3145 | } | |
4cd2e0e7 EB |
3146 | return 0; |
3147 | } | |
3148 | ||
601d5abf EB |
3149 | static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to, |
3150 | const siginfo_t __user *from) | |
3151 | { | |
3152 | if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) | |
3153 | return -EFAULT; | |
3154 | to->si_signo = signo; | |
3155 | return post_copy_siginfo_from_user(to, from); | |
3156 | } | |
3157 | ||
3158 | int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from) | |
3159 | { | |
3160 | if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) | |
3161 | return -EFAULT; | |
3162 | return post_copy_siginfo_from_user(to, from); | |
3163 | } | |
3164 | ||
212a36a1 | 3165 | #ifdef CONFIG_COMPAT |
ea64d5ac | 3166 | int copy_siginfo_to_user32(struct compat_siginfo __user *to, |
ae7795bc | 3167 | const struct kernel_siginfo *from) |
ea64d5ac EB |
3168 | #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION) |
3169 | { | |
3170 | return __copy_siginfo_to_user32(to, from, in_x32_syscall()); | |
3171 | } | |
3172 | int __copy_siginfo_to_user32(struct compat_siginfo __user *to, | |
ae7795bc | 3173 | const struct kernel_siginfo *from, bool x32_ABI) |
ea64d5ac EB |
3174 | #endif |
3175 | { | |
3176 | struct compat_siginfo new; | |
3177 | memset(&new, 0, sizeof(new)); | |
3178 | ||
3179 | new.si_signo = from->si_signo; | |
3180 | new.si_errno = from->si_errno; | |
3181 | new.si_code = from->si_code; | |
3182 | switch(siginfo_layout(from->si_signo, from->si_code)) { | |
3183 | case SIL_KILL: | |
3184 | new.si_pid = from->si_pid; | |
3185 | new.si_uid = from->si_uid; | |
3186 | break; | |
3187 | case SIL_TIMER: | |
3188 | new.si_tid = from->si_tid; | |
3189 | new.si_overrun = from->si_overrun; | |
3190 | new.si_int = from->si_int; | |
3191 | break; | |
3192 | case SIL_POLL: | |
3193 | new.si_band = from->si_band; | |
3194 | new.si_fd = from->si_fd; | |
3195 | break; | |
3196 | case SIL_FAULT: | |
3197 | new.si_addr = ptr_to_compat(from->si_addr); | |
3198 | #ifdef __ARCH_SI_TRAPNO | |
3199 | new.si_trapno = from->si_trapno; | |
3200 | #endif | |
31931c93 EB |
3201 | break; |
3202 | case SIL_FAULT_MCEERR: | |
3203 | new.si_addr = ptr_to_compat(from->si_addr); | |
3204 | #ifdef __ARCH_SI_TRAPNO | |
3205 | new.si_trapno = from->si_trapno; | |
ea64d5ac | 3206 | #endif |
31931c93 EB |
3207 | new.si_addr_lsb = from->si_addr_lsb; |
3208 | break; | |
3209 | case SIL_FAULT_BNDERR: | |
3210 | new.si_addr = ptr_to_compat(from->si_addr); | |
3211 | #ifdef __ARCH_SI_TRAPNO | |
3212 | new.si_trapno = from->si_trapno; | |
ea64d5ac | 3213 | #endif |
31931c93 EB |
3214 | new.si_lower = ptr_to_compat(from->si_lower); |
3215 | new.si_upper = ptr_to_compat(from->si_upper); | |
3216 | break; | |
3217 | case SIL_FAULT_PKUERR: | |
3218 | new.si_addr = ptr_to_compat(from->si_addr); | |
3219 | #ifdef __ARCH_SI_TRAPNO | |
3220 | new.si_trapno = from->si_trapno; | |
ea64d5ac | 3221 | #endif |
31931c93 | 3222 | new.si_pkey = from->si_pkey; |
ea64d5ac EB |
3223 | break; |
3224 | case SIL_CHLD: | |
3225 | new.si_pid = from->si_pid; | |
3226 | new.si_uid = from->si_uid; | |
3227 | new.si_status = from->si_status; | |
3228 | #ifdef CONFIG_X86_X32_ABI | |
3229 | if (x32_ABI) { | |
3230 | new._sifields._sigchld_x32._utime = from->si_utime; | |
3231 | new._sifields._sigchld_x32._stime = from->si_stime; | |
3232 | } else | |
3233 | #endif | |
3234 | { | |
3235 | new.si_utime = from->si_utime; | |
3236 | new.si_stime = from->si_stime; | |
3237 | } | |
3238 | break; | |
3239 | case SIL_RT: | |
3240 | new.si_pid = from->si_pid; | |
3241 | new.si_uid = from->si_uid; | |
3242 | new.si_int = from->si_int; | |
3243 | break; | |
3244 | case SIL_SYS: | |
3245 | new.si_call_addr = ptr_to_compat(from->si_call_addr); | |
3246 | new.si_syscall = from->si_syscall; | |
3247 | new.si_arch = from->si_arch; | |
3248 | break; | |
3249 | } | |
3250 | ||
3251 | if (copy_to_user(to, &new, sizeof(struct compat_siginfo))) | |
3252 | return -EFAULT; | |
3253 | ||
3254 | return 0; | |
3255 | } | |
3256 | ||
601d5abf EB |
3257 | static int post_copy_siginfo_from_user32(kernel_siginfo_t *to, |
3258 | const struct compat_siginfo *from) | |
212a36a1 | 3259 | { |
212a36a1 | 3260 | clear_siginfo(to); |
601d5abf EB |
3261 | to->si_signo = from->si_signo; |
3262 | to->si_errno = from->si_errno; | |
3263 | to->si_code = from->si_code; | |
3264 | switch(siginfo_layout(from->si_signo, from->si_code)) { | |
212a36a1 | 3265 | case SIL_KILL: |
601d5abf EB |
3266 | to->si_pid = from->si_pid; |
3267 | to->si_uid = from->si_uid; | |
212a36a1 EB |
3268 | break; |
3269 | case SIL_TIMER: | |
601d5abf EB |
3270 | to->si_tid = from->si_tid; |
3271 | to->si_overrun = from->si_overrun; | |
3272 | to->si_int = from->si_int; | |
212a36a1 EB |
3273 | break; |
3274 | case SIL_POLL: | |
601d5abf EB |
3275 | to->si_band = from->si_band; |
3276 | to->si_fd = from->si_fd; | |
212a36a1 EB |
3277 | break; |
3278 | case SIL_FAULT: | |
601d5abf | 3279 | to->si_addr = compat_ptr(from->si_addr); |
212a36a1 | 3280 | #ifdef __ARCH_SI_TRAPNO |
601d5abf | 3281 | to->si_trapno = from->si_trapno; |
212a36a1 | 3282 | #endif |
31931c93 EB |
3283 | break; |
3284 | case SIL_FAULT_MCEERR: | |
601d5abf | 3285 | to->si_addr = compat_ptr(from->si_addr); |
31931c93 | 3286 | #ifdef __ARCH_SI_TRAPNO |
601d5abf | 3287 | to->si_trapno = from->si_trapno; |
212a36a1 | 3288 | #endif |
601d5abf | 3289 | to->si_addr_lsb = from->si_addr_lsb; |
31931c93 EB |
3290 | break; |
3291 | case SIL_FAULT_BNDERR: | |
601d5abf | 3292 | to->si_addr = compat_ptr(from->si_addr); |
31931c93 | 3293 | #ifdef __ARCH_SI_TRAPNO |
601d5abf | 3294 | to->si_trapno = from->si_trapno; |
212a36a1 | 3295 | #endif |
601d5abf EB |
3296 | to->si_lower = compat_ptr(from->si_lower); |
3297 | to->si_upper = compat_ptr(from->si_upper); | |
31931c93 EB |
3298 | break; |
3299 | case SIL_FAULT_PKUERR: | |
601d5abf | 3300 | to->si_addr = compat_ptr(from->si_addr); |
31931c93 | 3301 | #ifdef __ARCH_SI_TRAPNO |
601d5abf | 3302 | to->si_trapno = from->si_trapno; |
212a36a1 | 3303 | #endif |
601d5abf | 3304 | to->si_pkey = from->si_pkey; |
212a36a1 EB |
3305 | break; |
3306 | case SIL_CHLD: | |
601d5abf EB |
3307 | to->si_pid = from->si_pid; |
3308 | to->si_uid = from->si_uid; | |
3309 | to->si_status = from->si_status; | |
212a36a1 EB |
3310 | #ifdef CONFIG_X86_X32_ABI |
3311 | if (in_x32_syscall()) { | |
601d5abf EB |
3312 | to->si_utime = from->_sifields._sigchld_x32._utime; |
3313 | to->si_stime = from->_sifields._sigchld_x32._stime; | |
212a36a1 EB |
3314 | } else |
3315 | #endif | |
3316 | { | |
601d5abf EB |
3317 | to->si_utime = from->si_utime; |
3318 | to->si_stime = from->si_stime; | |
212a36a1 EB |
3319 | } |
3320 | break; | |
3321 | case SIL_RT: | |
601d5abf EB |
3322 | to->si_pid = from->si_pid; |
3323 | to->si_uid = from->si_uid; | |
3324 | to->si_int = from->si_int; | |
212a36a1 EB |
3325 | break; |
3326 | case SIL_SYS: | |
601d5abf EB |
3327 | to->si_call_addr = compat_ptr(from->si_call_addr); |
3328 | to->si_syscall = from->si_syscall; | |
3329 | to->si_arch = from->si_arch; | |
212a36a1 EB |
3330 | break; |
3331 | } | |
3332 | return 0; | |
3333 | } | |
601d5abf EB |
3334 | |
3335 | static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to, | |
3336 | const struct compat_siginfo __user *ufrom) | |
3337 | { | |
3338 | struct compat_siginfo from; | |
3339 | ||
3340 | if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) | |
3341 | return -EFAULT; | |
3342 | ||
3343 | from.si_signo = signo; | |
3344 | return post_copy_siginfo_from_user32(to, &from); | |
3345 | } | |
3346 | ||
3347 | int copy_siginfo_from_user32(struct kernel_siginfo *to, | |
3348 | const struct compat_siginfo __user *ufrom) | |
3349 | { | |
3350 | struct compat_siginfo from; | |
3351 | ||
3352 | if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) | |
3353 | return -EFAULT; | |
3354 | ||
3355 | return post_copy_siginfo_from_user32(to, &from); | |
3356 | } | |
212a36a1 EB |
3357 | #endif /* CONFIG_COMPAT */ |
3358 | ||
943df148 ON |
3359 | /** |
3360 | * do_sigtimedwait - wait for queued signals specified in @which | |
3361 | * @which: queued signals to wait for | |
3362 | * @info: if non-null, the signal's siginfo is returned here | |
3363 | * @ts: upper bound on process time suspension | |
3364 | */ | |
ae7795bc | 3365 | static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info, |
49c39f84 | 3366 | const struct timespec64 *ts) |
943df148 | 3367 | { |
2456e855 | 3368 | ktime_t *to = NULL, timeout = KTIME_MAX; |
943df148 | 3369 | struct task_struct *tsk = current; |
943df148 | 3370 | sigset_t mask = *which; |
2b1ecc3d | 3371 | int sig, ret = 0; |
943df148 ON |
3372 | |
3373 | if (ts) { | |
49c39f84 | 3374 | if (!timespec64_valid(ts)) |
943df148 | 3375 | return -EINVAL; |
49c39f84 | 3376 | timeout = timespec64_to_ktime(*ts); |
2b1ecc3d | 3377 | to = &timeout; |
943df148 ON |
3378 | } |
3379 | ||
3380 | /* | |
3381 | * Invert the set of allowed signals to get those we want to block. | |
3382 | */ | |
3383 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
3384 | signotset(&mask); | |
3385 | ||
3386 | spin_lock_irq(&tsk->sighand->siglock); | |
3387 | sig = dequeue_signal(tsk, &mask, info); | |
2456e855 | 3388 | if (!sig && timeout) { |
943df148 ON |
3389 | /* |
3390 | * None ready, temporarily unblock those we're interested | |
3391 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
3392 | * they arrive. Unblocking is always fine, we can avoid |
3393 | * set_current_blocked(). | |
943df148 ON |
3394 | */ |
3395 | tsk->real_blocked = tsk->blocked; | |
3396 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
3397 | recalc_sigpending(); | |
3398 | spin_unlock_irq(&tsk->sighand->siglock); | |
3399 | ||
2b1ecc3d TG |
3400 | __set_current_state(TASK_INTERRUPTIBLE); |
3401 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, | |
3402 | HRTIMER_MODE_REL); | |
943df148 | 3403 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 3404 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 3405 | sigemptyset(&tsk->real_blocked); |
b182801a | 3406 | sig = dequeue_signal(tsk, &mask, info); |
943df148 ON |
3407 | } |
3408 | spin_unlock_irq(&tsk->sighand->siglock); | |
3409 | ||
3410 | if (sig) | |
3411 | return sig; | |
2b1ecc3d | 3412 | return ret ? -EINTR : -EAGAIN; |
943df148 ON |
3413 | } |
3414 | ||
41c57892 RD |
3415 | /** |
3416 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
3417 | * in @uthese | |
3418 | * @uthese: queued signals to wait for | |
3419 | * @uinfo: if non-null, the signal's siginfo is returned here | |
3420 | * @uts: upper bound on process time suspension | |
3421 | * @sigsetsize: size of sigset_t type | |
3422 | */ | |
17da2bd9 | 3423 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
49c39f84 AB |
3424 | siginfo_t __user *, uinfo, |
3425 | const struct __kernel_timespec __user *, uts, | |
17da2bd9 | 3426 | size_t, sigsetsize) |
1da177e4 | 3427 | { |
1da177e4 | 3428 | sigset_t these; |
49c39f84 | 3429 | struct timespec64 ts; |
ae7795bc | 3430 | kernel_siginfo_t info; |
943df148 | 3431 | int ret; |
1da177e4 LT |
3432 | |
3433 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3434 | if (sigsetsize != sizeof(sigset_t)) | |
3435 | return -EINVAL; | |
3436 | ||
3437 | if (copy_from_user(&these, uthese, sizeof(these))) | |
3438 | return -EFAULT; | |
5aba085e | 3439 | |
1da177e4 | 3440 | if (uts) { |
49c39f84 | 3441 | if (get_timespec64(&ts, uts)) |
1da177e4 | 3442 | return -EFAULT; |
1da177e4 LT |
3443 | } |
3444 | ||
943df148 | 3445 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 3446 | |
943df148 ON |
3447 | if (ret > 0 && uinfo) { |
3448 | if (copy_siginfo_to_user(uinfo, &info)) | |
3449 | ret = -EFAULT; | |
1da177e4 LT |
3450 | } |
3451 | ||
3452 | return ret; | |
3453 | } | |
3454 | ||
df8522a3 AB |
3455 | #ifdef CONFIG_COMPAT_32BIT_TIME |
3456 | SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese, | |
3457 | siginfo_t __user *, uinfo, | |
3458 | const struct old_timespec32 __user *, uts, | |
3459 | size_t, sigsetsize) | |
3460 | { | |
3461 | sigset_t these; | |
3462 | struct timespec64 ts; | |
3463 | kernel_siginfo_t info; | |
3464 | int ret; | |
3465 | ||
3466 | if (sigsetsize != sizeof(sigset_t)) | |
3467 | return -EINVAL; | |
3468 | ||
3469 | if (copy_from_user(&these, uthese, sizeof(these))) | |
3470 | return -EFAULT; | |
3471 | ||
3472 | if (uts) { | |
3473 | if (get_old_timespec32(&ts, uts)) | |
3474 | return -EFAULT; | |
3475 | } | |
3476 | ||
3477 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); | |
3478 | ||
3479 | if (ret > 0 && uinfo) { | |
3480 | if (copy_siginfo_to_user(uinfo, &info)) | |
3481 | ret = -EFAULT; | |
3482 | } | |
3483 | ||
3484 | return ret; | |
3485 | } | |
3486 | #endif | |
3487 | ||
1b3c872c | 3488 | #ifdef CONFIG_COMPAT |
2367c4b5 AB |
3489 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese, |
3490 | struct compat_siginfo __user *, uinfo, | |
3491 | struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize) | |
3492 | { | |
3493 | sigset_t s; | |
3494 | struct timespec64 t; | |
3495 | kernel_siginfo_t info; | |
3496 | long ret; | |
3497 | ||
3498 | if (sigsetsize != sizeof(sigset_t)) | |
3499 | return -EINVAL; | |
3500 | ||
3501 | if (get_compat_sigset(&s, uthese)) | |
3502 | return -EFAULT; | |
3503 | ||
3504 | if (uts) { | |
3505 | if (get_timespec64(&t, uts)) | |
3506 | return -EFAULT; | |
3507 | } | |
3508 | ||
3509 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); | |
3510 | ||
3511 | if (ret > 0 && uinfo) { | |
3512 | if (copy_siginfo_to_user32(uinfo, &info)) | |
3513 | ret = -EFAULT; | |
3514 | } | |
3515 | ||
3516 | return ret; | |
3517 | } | |
3518 | ||
3519 | #ifdef CONFIG_COMPAT_32BIT_TIME | |
8dabe724 | 3520 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese, |
1b3c872c | 3521 | struct compat_siginfo __user *, uinfo, |
9afc5eee | 3522 | struct old_timespec32 __user *, uts, compat_size_t, sigsetsize) |
1b3c872c | 3523 | { |
1b3c872c | 3524 | sigset_t s; |
49c39f84 | 3525 | struct timespec64 t; |
ae7795bc | 3526 | kernel_siginfo_t info; |
1b3c872c AV |
3527 | long ret; |
3528 | ||
3529 | if (sigsetsize != sizeof(sigset_t)) | |
3530 | return -EINVAL; | |
3531 | ||
3968cf62 | 3532 | if (get_compat_sigset(&s, uthese)) |
1b3c872c | 3533 | return -EFAULT; |
1b3c872c AV |
3534 | |
3535 | if (uts) { | |
49c39f84 | 3536 | if (get_old_timespec32(&t, uts)) |
1b3c872c AV |
3537 | return -EFAULT; |
3538 | } | |
3539 | ||
3540 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); | |
3541 | ||
3542 | if (ret > 0 && uinfo) { | |
3543 | if (copy_siginfo_to_user32(uinfo, &info)) | |
3544 | ret = -EFAULT; | |
3545 | } | |
3546 | ||
3547 | return ret; | |
3548 | } | |
3549 | #endif | |
2367c4b5 | 3550 | #endif |
1b3c872c | 3551 | |
3eb39f47 CB |
3552 | static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info) |
3553 | { | |
3554 | clear_siginfo(info); | |
3555 | info->si_signo = sig; | |
3556 | info->si_errno = 0; | |
3557 | info->si_code = SI_USER; | |
3558 | info->si_pid = task_tgid_vnr(current); | |
3559 | info->si_uid = from_kuid_munged(current_user_ns(), current_uid()); | |
3560 | } | |
3561 | ||
41c57892 RD |
3562 | /** |
3563 | * sys_kill - send a signal to a process | |
3564 | * @pid: the PID of the process | |
3565 | * @sig: signal to be sent | |
3566 | */ | |
17da2bd9 | 3567 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 | 3568 | { |
ae7795bc | 3569 | struct kernel_siginfo info; |
1da177e4 | 3570 | |
3eb39f47 | 3571 | prepare_kill_siginfo(sig, &info); |
1da177e4 LT |
3572 | |
3573 | return kill_something_info(sig, &info, pid); | |
3574 | } | |
3575 | ||
3eb39f47 CB |
3576 | /* |
3577 | * Verify that the signaler and signalee either are in the same pid namespace | |
3578 | * or that the signaler's pid namespace is an ancestor of the signalee's pid | |
3579 | * namespace. | |
3580 | */ | |
3581 | static bool access_pidfd_pidns(struct pid *pid) | |
3582 | { | |
3583 | struct pid_namespace *active = task_active_pid_ns(current); | |
3584 | struct pid_namespace *p = ns_of_pid(pid); | |
3585 | ||
3586 | for (;;) { | |
3587 | if (!p) | |
3588 | return false; | |
3589 | if (p == active) | |
3590 | break; | |
3591 | p = p->parent; | |
3592 | } | |
3593 | ||
3594 | return true; | |
3595 | } | |
3596 | ||
3597 | static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info) | |
3598 | { | |
3599 | #ifdef CONFIG_COMPAT | |
3600 | /* | |
3601 | * Avoid hooking up compat syscalls and instead handle necessary | |
3602 | * conversions here. Note, this is a stop-gap measure and should not be | |
3603 | * considered a generic solution. | |
3604 | */ | |
3605 | if (in_compat_syscall()) | |
3606 | return copy_siginfo_from_user32( | |
3607 | kinfo, (struct compat_siginfo __user *)info); | |
3608 | #endif | |
3609 | return copy_siginfo_from_user(kinfo, info); | |
3610 | } | |
3611 | ||
2151ad1b CB |
3612 | static struct pid *pidfd_to_pid(const struct file *file) |
3613 | { | |
3614 | if (file->f_op == &pidfd_fops) | |
3615 | return file->private_data; | |
3616 | ||
3617 | return tgid_pidfd_to_pid(file); | |
3618 | } | |
3619 | ||
3eb39f47 CB |
3620 | /** |
3621 | * sys_pidfd_send_signal - send a signal to a process through a task file | |
3622 | * descriptor | |
3623 | * @pidfd: the file descriptor of the process | |
3624 | * @sig: signal to be sent | |
3625 | * @info: the signal info | |
3626 | * @flags: future flags to be passed | |
3627 | * | |
3628 | * The syscall currently only signals via PIDTYPE_PID which covers | |
3629 | * kill(<positive-pid>, <signal>. It does not signal threads or process | |
3630 | * groups. | |
3631 | * In order to extend the syscall to threads and process groups the @flags | |
3632 | * argument should be used. In essence, the @flags argument will determine | |
3633 | * what is signaled and not the file descriptor itself. Put in other words, | |
3634 | * grouping is a property of the flags argument not a property of the file | |
3635 | * descriptor. | |
3636 | * | |
3637 | * Return: 0 on success, negative errno on failure | |
3638 | */ | |
3639 | SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, | |
3640 | siginfo_t __user *, info, unsigned int, flags) | |
3641 | { | |
3642 | int ret; | |
3643 | struct fd f; | |
3644 | struct pid *pid; | |
3645 | kernel_siginfo_t kinfo; | |
3646 | ||
3647 | /* Enforce flags be set to 0 until we add an extension. */ | |
3648 | if (flags) | |
3649 | return -EINVAL; | |
3650 | ||
738a7832 | 3651 | f = fdget(pidfd); |
3eb39f47 CB |
3652 | if (!f.file) |
3653 | return -EBADF; | |
3654 | ||
3655 | /* Is this a pidfd? */ | |
2151ad1b | 3656 | pid = pidfd_to_pid(f.file); |
3eb39f47 CB |
3657 | if (IS_ERR(pid)) { |
3658 | ret = PTR_ERR(pid); | |
3659 | goto err; | |
3660 | } | |
3661 | ||
3662 | ret = -EINVAL; | |
3663 | if (!access_pidfd_pidns(pid)) | |
3664 | goto err; | |
3665 | ||
3666 | if (info) { | |
3667 | ret = copy_siginfo_from_user_any(&kinfo, info); | |
3668 | if (unlikely(ret)) | |
3669 | goto err; | |
3670 | ||
3671 | ret = -EINVAL; | |
3672 | if (unlikely(sig != kinfo.si_signo)) | |
3673 | goto err; | |
3674 | ||
556a888a JH |
3675 | /* Only allow sending arbitrary signals to yourself. */ |
3676 | ret = -EPERM; | |
3eb39f47 | 3677 | if ((task_pid(current) != pid) && |
556a888a JH |
3678 | (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) |
3679 | goto err; | |
3eb39f47 CB |
3680 | } else { |
3681 | prepare_kill_siginfo(sig, &kinfo); | |
3682 | } | |
3683 | ||
3684 | ret = kill_pid_info(sig, &kinfo, pid); | |
3685 | ||
3686 | err: | |
3687 | fdput(f); | |
3688 | return ret; | |
3689 | } | |
3eb39f47 | 3690 | |
30b4ae8a | 3691 | static int |
ae7795bc | 3692 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info) |
1da177e4 | 3693 | { |
1da177e4 | 3694 | struct task_struct *p; |
30b4ae8a | 3695 | int error = -ESRCH; |
1da177e4 | 3696 | |
3547ff3a | 3697 | rcu_read_lock(); |
228ebcbe | 3698 | p = find_task_by_vpid(pid); |
b488893a | 3699 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 3700 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
3701 | /* |
3702 | * The null signal is a permissions and process existence | |
3703 | * probe. No signal is actually delivered. | |
3704 | */ | |
4a30debf | 3705 | if (!error && sig) { |
40b3b025 | 3706 | error = do_send_sig_info(sig, info, p, PIDTYPE_PID); |
4a30debf ON |
3707 | /* |
3708 | * If lock_task_sighand() failed we pretend the task | |
3709 | * dies after receiving the signal. The window is tiny, | |
3710 | * and the signal is private anyway. | |
3711 | */ | |
3712 | if (unlikely(error == -ESRCH)) | |
3713 | error = 0; | |
1da177e4 LT |
3714 | } |
3715 | } | |
3547ff3a | 3716 | rcu_read_unlock(); |
6dd69f10 | 3717 | |
1da177e4 LT |
3718 | return error; |
3719 | } | |
3720 | ||
30b4ae8a TG |
3721 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
3722 | { | |
ae7795bc | 3723 | struct kernel_siginfo info; |
30b4ae8a | 3724 | |
5f74972c | 3725 | clear_siginfo(&info); |
30b4ae8a TG |
3726 | info.si_signo = sig; |
3727 | info.si_errno = 0; | |
3728 | info.si_code = SI_TKILL; | |
3729 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 3730 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
3731 | |
3732 | return do_send_specific(tgid, pid, sig, &info); | |
3733 | } | |
3734 | ||
6dd69f10 VL |
3735 | /** |
3736 | * sys_tgkill - send signal to one specific thread | |
3737 | * @tgid: the thread group ID of the thread | |
3738 | * @pid: the PID of the thread | |
3739 | * @sig: signal to be sent | |
3740 | * | |
72fd4a35 | 3741 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
3742 | * exists but it's not belonging to the target process anymore. This |
3743 | * method solves the problem of threads exiting and PIDs getting reused. | |
3744 | */ | |
a5f8fa9e | 3745 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
3746 | { |
3747 | /* This is only valid for single tasks */ | |
3748 | if (pid <= 0 || tgid <= 0) | |
3749 | return -EINVAL; | |
3750 | ||
3751 | return do_tkill(tgid, pid, sig); | |
3752 | } | |
3753 | ||
41c57892 RD |
3754 | /** |
3755 | * sys_tkill - send signal to one specific task | |
3756 | * @pid: the PID of the task | |
3757 | * @sig: signal to be sent | |
3758 | * | |
1da177e4 LT |
3759 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
3760 | */ | |
a5f8fa9e | 3761 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 3762 | { |
1da177e4 LT |
3763 | /* This is only valid for single tasks */ |
3764 | if (pid <= 0) | |
3765 | return -EINVAL; | |
3766 | ||
6dd69f10 | 3767 | return do_tkill(0, pid, sig); |
1da177e4 LT |
3768 | } |
3769 | ||
ae7795bc | 3770 | static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info) |
75907d4d AV |
3771 | { |
3772 | /* Not even root can pretend to send signals from the kernel. | |
3773 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
3774 | */ | |
66dd34ad | 3775 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
69828dce | 3776 | (task_pid_vnr(current) != pid)) |
75907d4d | 3777 | return -EPERM; |
69828dce | 3778 | |
75907d4d AV |
3779 | /* POSIX.1b doesn't mention process groups. */ |
3780 | return kill_proc_info(sig, info, pid); | |
3781 | } | |
3782 | ||
41c57892 RD |
3783 | /** |
3784 | * sys_rt_sigqueueinfo - send signal information to a signal | |
3785 | * @pid: the PID of the thread | |
3786 | * @sig: signal to be sent | |
3787 | * @uinfo: signal info to be sent | |
3788 | */ | |
a5f8fa9e HC |
3789 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
3790 | siginfo_t __user *, uinfo) | |
1da177e4 | 3791 | { |
ae7795bc | 3792 | kernel_siginfo_t info; |
601d5abf | 3793 | int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
4cd2e0e7 EB |
3794 | if (unlikely(ret)) |
3795 | return ret; | |
75907d4d AV |
3796 | return do_rt_sigqueueinfo(pid, sig, &info); |
3797 | } | |
1da177e4 | 3798 | |
75907d4d | 3799 | #ifdef CONFIG_COMPAT |
75907d4d AV |
3800 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
3801 | compat_pid_t, pid, | |
3802 | int, sig, | |
3803 | struct compat_siginfo __user *, uinfo) | |
3804 | { | |
ae7795bc | 3805 | kernel_siginfo_t info; |
601d5abf | 3806 | int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
75907d4d AV |
3807 | if (unlikely(ret)) |
3808 | return ret; | |
3809 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 3810 | } |
75907d4d | 3811 | #endif |
1da177e4 | 3812 | |
ae7795bc | 3813 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info) |
62ab4505 TG |
3814 | { |
3815 | /* This is only valid for single tasks */ | |
3816 | if (pid <= 0 || tgid <= 0) | |
3817 | return -EINVAL; | |
3818 | ||
3819 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
3820 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
3821 | */ | |
69828dce VD |
3822 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
3823 | (task_pid_vnr(current) != pid)) | |
62ab4505 | 3824 | return -EPERM; |
69828dce | 3825 | |
62ab4505 TG |
3826 | return do_send_specific(tgid, pid, sig, info); |
3827 | } | |
3828 | ||
3829 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
3830 | siginfo_t __user *, uinfo) | |
3831 | { | |
ae7795bc | 3832 | kernel_siginfo_t info; |
601d5abf | 3833 | int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
4cd2e0e7 EB |
3834 | if (unlikely(ret)) |
3835 | return ret; | |
62ab4505 TG |
3836 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
3837 | } | |
3838 | ||
9aae8fc0 AV |
3839 | #ifdef CONFIG_COMPAT |
3840 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
3841 | compat_pid_t, tgid, | |
3842 | compat_pid_t, pid, | |
3843 | int, sig, | |
3844 | struct compat_siginfo __user *, uinfo) | |
3845 | { | |
ae7795bc | 3846 | kernel_siginfo_t info; |
601d5abf | 3847 | int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
4cd2e0e7 EB |
3848 | if (unlikely(ret)) |
3849 | return ret; | |
9aae8fc0 AV |
3850 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
3851 | } | |
3852 | #endif | |
3853 | ||
0341729b | 3854 | /* |
b4e74264 | 3855 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
0341729b | 3856 | */ |
b4e74264 | 3857 | void kernel_sigaction(int sig, __sighandler_t action) |
0341729b | 3858 | { |
ec5955b8 | 3859 | spin_lock_irq(¤t->sighand->siglock); |
b4e74264 ON |
3860 | current->sighand->action[sig - 1].sa.sa_handler = action; |
3861 | if (action == SIG_IGN) { | |
3862 | sigset_t mask; | |
0341729b | 3863 | |
b4e74264 ON |
3864 | sigemptyset(&mask); |
3865 | sigaddset(&mask, sig); | |
580d34e4 | 3866 | |
b4e74264 ON |
3867 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
3868 | flush_sigqueue_mask(&mask, ¤t->pending); | |
3869 | recalc_sigpending(); | |
3870 | } | |
0341729b ON |
3871 | spin_unlock_irq(¤t->sighand->siglock); |
3872 | } | |
b4e74264 | 3873 | EXPORT_SYMBOL(kernel_sigaction); |
0341729b | 3874 | |
68463510 DS |
3875 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
3876 | struct k_sigaction *oact) | |
3877 | { | |
3878 | } | |
3879 | ||
88531f72 | 3880 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 3881 | { |
afe2b038 | 3882 | struct task_struct *p = current, *t; |
1da177e4 | 3883 | struct k_sigaction *k; |
71fabd5e | 3884 | sigset_t mask; |
1da177e4 | 3885 | |
7ed20e1a | 3886 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
3887 | return -EINVAL; |
3888 | ||
afe2b038 | 3889 | k = &p->sighand->action[sig-1]; |
1da177e4 | 3890 | |
afe2b038 | 3891 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
3892 | if (oact) |
3893 | *oact = *k; | |
3894 | ||
68463510 DS |
3895 | sigaction_compat_abi(act, oact); |
3896 | ||
1da177e4 | 3897 | if (act) { |
9ac95f2f ON |
3898 | sigdelsetmask(&act->sa.sa_mask, |
3899 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 3900 | *k = *act; |
1da177e4 LT |
3901 | /* |
3902 | * POSIX 3.3.1.3: | |
3903 | * "Setting a signal action to SIG_IGN for a signal that is | |
3904 | * pending shall cause the pending signal to be discarded, | |
3905 | * whether or not it is blocked." | |
3906 | * | |
3907 | * "Setting a signal action to SIG_DFL for a signal that is | |
3908 | * pending and whose default action is to ignore the signal | |
3909 | * (for example, SIGCHLD), shall cause the pending signal to | |
3910 | * be discarded, whether or not it is blocked" | |
3911 | */ | |
afe2b038 | 3912 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
71fabd5e GA |
3913 | sigemptyset(&mask); |
3914 | sigaddset(&mask, sig); | |
afe2b038 ON |
3915 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
3916 | for_each_thread(p, t) | |
c09c1441 | 3917 | flush_sigqueue_mask(&mask, &t->pending); |
1da177e4 | 3918 | } |
1da177e4 LT |
3919 | } |
3920 | ||
afe2b038 | 3921 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
3922 | return 0; |
3923 | } | |
3924 | ||
c09c1441 | 3925 | static int |
22839869 WD |
3926 | do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, |
3927 | size_t min_ss_size) | |
1da177e4 | 3928 | { |
bcfe8ad8 | 3929 | struct task_struct *t = current; |
1da177e4 | 3930 | |
bcfe8ad8 AV |
3931 | if (oss) { |
3932 | memset(oss, 0, sizeof(stack_t)); | |
3933 | oss->ss_sp = (void __user *) t->sas_ss_sp; | |
3934 | oss->ss_size = t->sas_ss_size; | |
3935 | oss->ss_flags = sas_ss_flags(sp) | | |
3936 | (current->sas_ss_flags & SS_FLAG_BITS); | |
3937 | } | |
1da177e4 | 3938 | |
bcfe8ad8 AV |
3939 | if (ss) { |
3940 | void __user *ss_sp = ss->ss_sp; | |
3941 | size_t ss_size = ss->ss_size; | |
3942 | unsigned ss_flags = ss->ss_flags; | |
407bc16a | 3943 | int ss_mode; |
1da177e4 | 3944 | |
bcfe8ad8 AV |
3945 | if (unlikely(on_sig_stack(sp))) |
3946 | return -EPERM; | |
1da177e4 | 3947 | |
407bc16a | 3948 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
bcfe8ad8 AV |
3949 | if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
3950 | ss_mode != 0)) | |
3951 | return -EINVAL; | |
1da177e4 | 3952 | |
407bc16a | 3953 | if (ss_mode == SS_DISABLE) { |
1da177e4 LT |
3954 | ss_size = 0; |
3955 | ss_sp = NULL; | |
3956 | } else { | |
22839869 | 3957 | if (unlikely(ss_size < min_ss_size)) |
bcfe8ad8 | 3958 | return -ENOMEM; |
1da177e4 LT |
3959 | } |
3960 | ||
bcfe8ad8 AV |
3961 | t->sas_ss_sp = (unsigned long) ss_sp; |
3962 | t->sas_ss_size = ss_size; | |
3963 | t->sas_ss_flags = ss_flags; | |
1da177e4 | 3964 | } |
bcfe8ad8 | 3965 | return 0; |
1da177e4 | 3966 | } |
bcfe8ad8 | 3967 | |
6bf9adfc AV |
3968 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
3969 | { | |
bcfe8ad8 AV |
3970 | stack_t new, old; |
3971 | int err; | |
3972 | if (uss && copy_from_user(&new, uss, sizeof(stack_t))) | |
3973 | return -EFAULT; | |
3974 | err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL, | |
22839869 WD |
3975 | current_user_stack_pointer(), |
3976 | MINSIGSTKSZ); | |
bcfe8ad8 AV |
3977 | if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t))) |
3978 | err = -EFAULT; | |
3979 | return err; | |
6bf9adfc | 3980 | } |
1da177e4 | 3981 | |
5c49574f AV |
3982 | int restore_altstack(const stack_t __user *uss) |
3983 | { | |
bcfe8ad8 AV |
3984 | stack_t new; |
3985 | if (copy_from_user(&new, uss, sizeof(stack_t))) | |
3986 | return -EFAULT; | |
22839869 WD |
3987 | (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(), |
3988 | MINSIGSTKSZ); | |
5c49574f | 3989 | /* squash all but EFAULT for now */ |
bcfe8ad8 | 3990 | return 0; |
5c49574f AV |
3991 | } |
3992 | ||
c40702c4 AV |
3993 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
3994 | { | |
3995 | struct task_struct *t = current; | |
2a742138 SS |
3996 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
3997 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 3998 | __put_user(t->sas_ss_size, &uss->ss_size); |
2a742138 SS |
3999 | if (err) |
4000 | return err; | |
4001 | if (t->sas_ss_flags & SS_AUTODISARM) | |
4002 | sas_ss_reset(t); | |
4003 | return 0; | |
c40702c4 AV |
4004 | } |
4005 | ||
90268439 | 4006 | #ifdef CONFIG_COMPAT |
6203deb0 DB |
4007 | static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr, |
4008 | compat_stack_t __user *uoss_ptr) | |
90268439 AV |
4009 | { |
4010 | stack_t uss, uoss; | |
4011 | int ret; | |
90268439 AV |
4012 | |
4013 | if (uss_ptr) { | |
4014 | compat_stack_t uss32; | |
90268439 AV |
4015 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) |
4016 | return -EFAULT; | |
4017 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
4018 | uss.ss_flags = uss32.ss_flags; | |
4019 | uss.ss_size = uss32.ss_size; | |
4020 | } | |
bcfe8ad8 | 4021 | ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, |
22839869 WD |
4022 | compat_user_stack_pointer(), |
4023 | COMPAT_MINSIGSTKSZ); | |
90268439 | 4024 | if (ret >= 0 && uoss_ptr) { |
bcfe8ad8 AV |
4025 | compat_stack_t old; |
4026 | memset(&old, 0, sizeof(old)); | |
4027 | old.ss_sp = ptr_to_compat(uoss.ss_sp); | |
4028 | old.ss_flags = uoss.ss_flags; | |
4029 | old.ss_size = uoss.ss_size; | |
4030 | if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t))) | |
90268439 AV |
4031 | ret = -EFAULT; |
4032 | } | |
4033 | return ret; | |
4034 | } | |
4035 | ||
6203deb0 DB |
4036 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
4037 | const compat_stack_t __user *, uss_ptr, | |
4038 | compat_stack_t __user *, uoss_ptr) | |
4039 | { | |
4040 | return do_compat_sigaltstack(uss_ptr, uoss_ptr); | |
4041 | } | |
4042 | ||
90268439 AV |
4043 | int compat_restore_altstack(const compat_stack_t __user *uss) |
4044 | { | |
6203deb0 | 4045 | int err = do_compat_sigaltstack(uss, NULL); |
90268439 AV |
4046 | /* squash all but -EFAULT for now */ |
4047 | return err == -EFAULT ? err : 0; | |
4048 | } | |
c40702c4 AV |
4049 | |
4050 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
4051 | { | |
441398d3 | 4052 | int err; |
c40702c4 | 4053 | struct task_struct *t = current; |
441398d3 SS |
4054 | err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
4055 | &uss->ss_sp) | | |
4056 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 4057 | __put_user(t->sas_ss_size, &uss->ss_size); |
441398d3 SS |
4058 | if (err) |
4059 | return err; | |
4060 | if (t->sas_ss_flags & SS_AUTODISARM) | |
4061 | sas_ss_reset(t); | |
4062 | return 0; | |
c40702c4 | 4063 | } |
90268439 | 4064 | #endif |
1da177e4 LT |
4065 | |
4066 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
4067 | ||
41c57892 RD |
4068 | /** |
4069 | * sys_sigpending - examine pending signals | |
d53238cd | 4070 | * @uset: where mask of pending signal is returned |
41c57892 | 4071 | */ |
d53238cd | 4072 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset) |
1da177e4 | 4073 | { |
d53238cd | 4074 | sigset_t set; |
d53238cd DB |
4075 | |
4076 | if (sizeof(old_sigset_t) > sizeof(*uset)) | |
4077 | return -EINVAL; | |
4078 | ||
b1d294c8 CB |
4079 | do_sigpending(&set); |
4080 | ||
4081 | if (copy_to_user(uset, &set, sizeof(old_sigset_t))) | |
4082 | return -EFAULT; | |
4083 | ||
4084 | return 0; | |
1da177e4 LT |
4085 | } |
4086 | ||
8f13621a AV |
4087 | #ifdef CONFIG_COMPAT |
4088 | COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) | |
4089 | { | |
4090 | sigset_t set; | |
b1d294c8 CB |
4091 | |
4092 | do_sigpending(&set); | |
4093 | ||
4094 | return put_user(set.sig[0], set32); | |
8f13621a AV |
4095 | } |
4096 | #endif | |
4097 | ||
1da177e4 LT |
4098 | #endif |
4099 | ||
4100 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
4101 | /** |
4102 | * sys_sigprocmask - examine and change blocked signals | |
4103 | * @how: whether to add, remove, or set signals | |
b013c399 | 4104 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
4105 | * @oset: previous value of signal mask if non-null |
4106 | * | |
5aba085e RD |
4107 | * Some platforms have their own version with special arguments; |
4108 | * others support only sys_rt_sigprocmask. | |
4109 | */ | |
1da177e4 | 4110 | |
b013c399 | 4111 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 4112 | old_sigset_t __user *, oset) |
1da177e4 | 4113 | { |
1da177e4 | 4114 | old_sigset_t old_set, new_set; |
2e4f7c77 | 4115 | sigset_t new_blocked; |
1da177e4 | 4116 | |
b013c399 | 4117 | old_set = current->blocked.sig[0]; |
1da177e4 | 4118 | |
b013c399 ON |
4119 | if (nset) { |
4120 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
4121 | return -EFAULT; | |
1da177e4 | 4122 | |
2e4f7c77 | 4123 | new_blocked = current->blocked; |
1da177e4 | 4124 | |
1da177e4 | 4125 | switch (how) { |
1da177e4 | 4126 | case SIG_BLOCK: |
2e4f7c77 | 4127 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
4128 | break; |
4129 | case SIG_UNBLOCK: | |
2e4f7c77 | 4130 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
4131 | break; |
4132 | case SIG_SETMASK: | |
2e4f7c77 | 4133 | new_blocked.sig[0] = new_set; |
1da177e4 | 4134 | break; |
2e4f7c77 ON |
4135 | default: |
4136 | return -EINVAL; | |
1da177e4 LT |
4137 | } |
4138 | ||
0c4a8423 | 4139 | set_current_blocked(&new_blocked); |
b013c399 ON |
4140 | } |
4141 | ||
4142 | if (oset) { | |
1da177e4 | 4143 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 4144 | return -EFAULT; |
1da177e4 | 4145 | } |
b013c399 ON |
4146 | |
4147 | return 0; | |
1da177e4 LT |
4148 | } |
4149 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
4150 | ||
eaca6eae | 4151 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
4152 | /** |
4153 | * sys_rt_sigaction - alter an action taken by a process | |
4154 | * @sig: signal to be sent | |
f9fa0bc1 RD |
4155 | * @act: new sigaction |
4156 | * @oact: used to save the previous sigaction | |
41c57892 RD |
4157 | * @sigsetsize: size of sigset_t type |
4158 | */ | |
d4e82042 HC |
4159 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
4160 | const struct sigaction __user *, act, | |
4161 | struct sigaction __user *, oact, | |
4162 | size_t, sigsetsize) | |
1da177e4 LT |
4163 | { |
4164 | struct k_sigaction new_sa, old_sa; | |
d8f993b3 | 4165 | int ret; |
1da177e4 LT |
4166 | |
4167 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4168 | if (sigsetsize != sizeof(sigset_t)) | |
d8f993b3 | 4169 | return -EINVAL; |
1da177e4 | 4170 | |
d8f993b3 CB |
4171 | if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) |
4172 | return -EFAULT; | |
1da177e4 LT |
4173 | |
4174 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
d8f993b3 CB |
4175 | if (ret) |
4176 | return ret; | |
1da177e4 | 4177 | |
d8f993b3 CB |
4178 | if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) |
4179 | return -EFAULT; | |
4180 | ||
4181 | return 0; | |
1da177e4 | 4182 | } |
08d32fe5 | 4183 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
4184 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
4185 | const struct compat_sigaction __user *, act, | |
4186 | struct compat_sigaction __user *, oact, | |
4187 | compat_size_t, sigsetsize) | |
4188 | { | |
4189 | struct k_sigaction new_ka, old_ka; | |
08d32fe5 AV |
4190 | #ifdef __ARCH_HAS_SA_RESTORER |
4191 | compat_uptr_t restorer; | |
4192 | #endif | |
4193 | int ret; | |
4194 | ||
4195 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4196 | if (sigsetsize != sizeof(compat_sigset_t)) | |
4197 | return -EINVAL; | |
4198 | ||
4199 | if (act) { | |
4200 | compat_uptr_t handler; | |
4201 | ret = get_user(handler, &act->sa_handler); | |
4202 | new_ka.sa.sa_handler = compat_ptr(handler); | |
4203 | #ifdef __ARCH_HAS_SA_RESTORER | |
4204 | ret |= get_user(restorer, &act->sa_restorer); | |
4205 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
4206 | #endif | |
3968cf62 | 4207 | ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask); |
3ddc5b46 | 4208 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
4209 | if (ret) |
4210 | return -EFAULT; | |
08d32fe5 AV |
4211 | } |
4212 | ||
4213 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
4214 | if (!ret && oact) { | |
08d32fe5 AV |
4215 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), |
4216 | &oact->sa_handler); | |
f454322e DL |
4217 | ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, |
4218 | sizeof(oact->sa_mask)); | |
3ddc5b46 | 4219 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
4220 | #ifdef __ARCH_HAS_SA_RESTORER |
4221 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
4222 | &oact->sa_restorer); | |
4223 | #endif | |
4224 | } | |
4225 | return ret; | |
4226 | } | |
4227 | #endif | |
eaca6eae | 4228 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 4229 | |
495dfbf7 AV |
4230 | #ifdef CONFIG_OLD_SIGACTION |
4231 | SYSCALL_DEFINE3(sigaction, int, sig, | |
4232 | const struct old_sigaction __user *, act, | |
4233 | struct old_sigaction __user *, oact) | |
4234 | { | |
4235 | struct k_sigaction new_ka, old_ka; | |
4236 | int ret; | |
4237 | ||
4238 | if (act) { | |
4239 | old_sigset_t mask; | |
96d4f267 | 4240 | if (!access_ok(act, sizeof(*act)) || |
495dfbf7 AV |
4241 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || |
4242 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
4243 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
4244 | __get_user(mask, &act->sa_mask)) | |
4245 | return -EFAULT; | |
4246 | #ifdef __ARCH_HAS_KA_RESTORER | |
4247 | new_ka.ka_restorer = NULL; | |
4248 | #endif | |
4249 | siginitset(&new_ka.sa.sa_mask, mask); | |
4250 | } | |
4251 | ||
4252 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
4253 | ||
4254 | if (!ret && oact) { | |
96d4f267 | 4255 | if (!access_ok(oact, sizeof(*oact)) || |
495dfbf7 AV |
4256 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || |
4257 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
4258 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
4259 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
4260 | return -EFAULT; | |
4261 | } | |
4262 | ||
4263 | return ret; | |
4264 | } | |
4265 | #endif | |
4266 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
4267 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
4268 | const struct compat_old_sigaction __user *, act, | |
4269 | struct compat_old_sigaction __user *, oact) | |
4270 | { | |
4271 | struct k_sigaction new_ka, old_ka; | |
4272 | int ret; | |
4273 | compat_old_sigset_t mask; | |
4274 | compat_uptr_t handler, restorer; | |
4275 | ||
4276 | if (act) { | |
96d4f267 | 4277 | if (!access_ok(act, sizeof(*act)) || |
495dfbf7 AV |
4278 | __get_user(handler, &act->sa_handler) || |
4279 | __get_user(restorer, &act->sa_restorer) || | |
4280 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
4281 | __get_user(mask, &act->sa_mask)) | |
4282 | return -EFAULT; | |
4283 | ||
4284 | #ifdef __ARCH_HAS_KA_RESTORER | |
4285 | new_ka.ka_restorer = NULL; | |
4286 | #endif | |
4287 | new_ka.sa.sa_handler = compat_ptr(handler); | |
4288 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
4289 | siginitset(&new_ka.sa.sa_mask, mask); | |
4290 | } | |
4291 | ||
4292 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
4293 | ||
4294 | if (!ret && oact) { | |
96d4f267 | 4295 | if (!access_ok(oact, sizeof(*oact)) || |
495dfbf7 AV |
4296 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), |
4297 | &oact->sa_handler) || | |
4298 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
4299 | &oact->sa_restorer) || | |
4300 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
4301 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
4302 | return -EFAULT; | |
4303 | } | |
4304 | return ret; | |
4305 | } | |
4306 | #endif | |
1da177e4 | 4307 | |
f6187769 | 4308 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
4309 | |
4310 | /* | |
4311 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
4312 | */ | |
a5f8fa9e | 4313 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
4314 | { |
4315 | /* SMP safe */ | |
4316 | return current->blocked.sig[0]; | |
4317 | } | |
4318 | ||
a5f8fa9e | 4319 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 4320 | { |
c1095c6d ON |
4321 | int old = current->blocked.sig[0]; |
4322 | sigset_t newset; | |
1da177e4 | 4323 | |
5ba53ff6 | 4324 | siginitset(&newset, newmask); |
c1095c6d | 4325 | set_current_blocked(&newset); |
1da177e4 LT |
4326 | |
4327 | return old; | |
4328 | } | |
f6187769 | 4329 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
4330 | |
4331 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
4332 | /* | |
4333 | * For backwards compatibility. Functionality superseded by sigaction. | |
4334 | */ | |
a5f8fa9e | 4335 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
4336 | { |
4337 | struct k_sigaction new_sa, old_sa; | |
4338 | int ret; | |
4339 | ||
4340 | new_sa.sa.sa_handler = handler; | |
4341 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 4342 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
4343 | |
4344 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
4345 | ||
4346 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
4347 | } | |
4348 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
4349 | ||
4350 | #ifdef __ARCH_WANT_SYS_PAUSE | |
4351 | ||
a5f8fa9e | 4352 | SYSCALL_DEFINE0(pause) |
1da177e4 | 4353 | { |
d92fcf05 | 4354 | while (!signal_pending(current)) { |
1df01355 | 4355 | __set_current_state(TASK_INTERRUPTIBLE); |
d92fcf05 ON |
4356 | schedule(); |
4357 | } | |
1da177e4 LT |
4358 | return -ERESTARTNOHAND; |
4359 | } | |
4360 | ||
4361 | #endif | |
4362 | ||
9d8a7652 | 4363 | static int sigsuspend(sigset_t *set) |
68f3f16d | 4364 | { |
68f3f16d AV |
4365 | current->saved_sigmask = current->blocked; |
4366 | set_current_blocked(set); | |
4367 | ||
823dd322 SL |
4368 | while (!signal_pending(current)) { |
4369 | __set_current_state(TASK_INTERRUPTIBLE); | |
4370 | schedule(); | |
4371 | } | |
68f3f16d AV |
4372 | set_restore_sigmask(); |
4373 | return -ERESTARTNOHAND; | |
4374 | } | |
68f3f16d | 4375 | |
41c57892 RD |
4376 | /** |
4377 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
4378 | * @unewset value until a signal is received | |
4379 | * @unewset: new signal mask value | |
4380 | * @sigsetsize: size of sigset_t type | |
4381 | */ | |
d4e82042 | 4382 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
4383 | { |
4384 | sigset_t newset; | |
4385 | ||
4386 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4387 | if (sigsetsize != sizeof(sigset_t)) | |
4388 | return -EINVAL; | |
4389 | ||
4390 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
4391 | return -EFAULT; | |
68f3f16d | 4392 | return sigsuspend(&newset); |
150256d8 | 4393 | } |
ad4b65a4 AV |
4394 | |
4395 | #ifdef CONFIG_COMPAT | |
4396 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
4397 | { | |
ad4b65a4 | 4398 | sigset_t newset; |
ad4b65a4 AV |
4399 | |
4400 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4401 | if (sigsetsize != sizeof(sigset_t)) | |
4402 | return -EINVAL; | |
4403 | ||
3968cf62 | 4404 | if (get_compat_sigset(&newset, unewset)) |
ad4b65a4 | 4405 | return -EFAULT; |
ad4b65a4 | 4406 | return sigsuspend(&newset); |
ad4b65a4 AV |
4407 | } |
4408 | #endif | |
150256d8 | 4409 | |
0a0e8cdf AV |
4410 | #ifdef CONFIG_OLD_SIGSUSPEND |
4411 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
4412 | { | |
4413 | sigset_t blocked; | |
4414 | siginitset(&blocked, mask); | |
4415 | return sigsuspend(&blocked); | |
4416 | } | |
4417 | #endif | |
4418 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
4419 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
4420 | { | |
4421 | sigset_t blocked; | |
4422 | siginitset(&blocked, mask); | |
4423 | return sigsuspend(&blocked); | |
4424 | } | |
4425 | #endif | |
150256d8 | 4426 | |
52f5684c | 4427 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
4428 | { |
4429 | return NULL; | |
4430 | } | |
4431 | ||
ae7795bc | 4432 | static inline void siginfo_buildtime_checks(void) |
1da177e4 | 4433 | { |
aba1be2f | 4434 | BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE); |
41b27154 | 4435 | |
ae7795bc EB |
4436 | /* Verify the offsets in the two siginfos match */ |
4437 | #define CHECK_OFFSET(field) \ | |
4438 | BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field)) | |
4439 | ||
4440 | /* kill */ | |
4441 | CHECK_OFFSET(si_pid); | |
4442 | CHECK_OFFSET(si_uid); | |
4443 | ||
4444 | /* timer */ | |
4445 | CHECK_OFFSET(si_tid); | |
4446 | CHECK_OFFSET(si_overrun); | |
4447 | CHECK_OFFSET(si_value); | |
4448 | ||
4449 | /* rt */ | |
4450 | CHECK_OFFSET(si_pid); | |
4451 | CHECK_OFFSET(si_uid); | |
4452 | CHECK_OFFSET(si_value); | |
4453 | ||
4454 | /* sigchld */ | |
4455 | CHECK_OFFSET(si_pid); | |
4456 | CHECK_OFFSET(si_uid); | |
4457 | CHECK_OFFSET(si_status); | |
4458 | CHECK_OFFSET(si_utime); | |
4459 | CHECK_OFFSET(si_stime); | |
4460 | ||
4461 | /* sigfault */ | |
4462 | CHECK_OFFSET(si_addr); | |
4463 | CHECK_OFFSET(si_addr_lsb); | |
4464 | CHECK_OFFSET(si_lower); | |
4465 | CHECK_OFFSET(si_upper); | |
4466 | CHECK_OFFSET(si_pkey); | |
4467 | ||
4468 | /* sigpoll */ | |
4469 | CHECK_OFFSET(si_band); | |
4470 | CHECK_OFFSET(si_fd); | |
4471 | ||
4472 | /* sigsys */ | |
4473 | CHECK_OFFSET(si_call_addr); | |
4474 | CHECK_OFFSET(si_syscall); | |
4475 | CHECK_OFFSET(si_arch); | |
4476 | #undef CHECK_OFFSET | |
4477 | } | |
4478 | ||
4479 | void __init signals_init(void) | |
4480 | { | |
4481 | siginfo_buildtime_checks(); | |
4482 | ||
0a31bd5f | 4483 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 4484 | } |
67fc4e0c JW |
4485 | |
4486 | #ifdef CONFIG_KGDB_KDB | |
4487 | #include <linux/kdb.h> | |
4488 | /* | |
0b44bf9a | 4489 | * kdb_send_sig - Allows kdb to send signals without exposing |
67fc4e0c JW |
4490 | * signal internals. This function checks if the required locks are |
4491 | * available before calling the main signal code, to avoid kdb | |
4492 | * deadlocks. | |
4493 | */ | |
0b44bf9a | 4494 | void kdb_send_sig(struct task_struct *t, int sig) |
67fc4e0c JW |
4495 | { |
4496 | static struct task_struct *kdb_prev_t; | |
0b44bf9a | 4497 | int new_t, ret; |
67fc4e0c JW |
4498 | if (!spin_trylock(&t->sighand->siglock)) { |
4499 | kdb_printf("Can't do kill command now.\n" | |
4500 | "The sigmask lock is held somewhere else in " | |
4501 | "kernel, try again later\n"); | |
4502 | return; | |
4503 | } | |
67fc4e0c JW |
4504 | new_t = kdb_prev_t != t; |
4505 | kdb_prev_t = t; | |
4506 | if (t->state != TASK_RUNNING && new_t) { | |
0b44bf9a | 4507 | spin_unlock(&t->sighand->siglock); |
67fc4e0c JW |
4508 | kdb_printf("Process is not RUNNING, sending a signal from " |
4509 | "kdb risks deadlock\n" | |
4510 | "on the run queue locks. " | |
4511 | "The signal has _not_ been sent.\n" | |
4512 | "Reissue the kill command if you want to risk " | |
4513 | "the deadlock.\n"); | |
4514 | return; | |
4515 | } | |
b213984b | 4516 | ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID); |
0b44bf9a EB |
4517 | spin_unlock(&t->sighand->siglock); |
4518 | if (ret) | |
67fc4e0c JW |
4519 | kdb_printf("Fail to deliver Signal %d to process %d.\n", |
4520 | sig, t->pid); | |
4521 | else | |
4522 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
4523 | } | |
4524 | #endif /* CONFIG_KGDB_KDB */ |