blob: 677102789cf22d4847936782f6c6f67085421927 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/slab.h>
Paul Gortmaker9984de12011-05-23 14:51:41 -040014#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/init.h>
16#include <linux/sched.h>
17#include <linux/fs.h>
18#include <linux/tty.h>
19#include <linux/binfmts.h>
20#include <linux/security.h>
21#include <linux/syscalls.h>
22#include <linux/ptrace.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070023#include <linux/signal.h>
Davide Libenzifba2afa2007-05-10 22:23:13 -070024#include <linux/signalfd.h>
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +090025#include <linux/ratelimit.h>
Roland McGrath35de2542008-07-25 19:45:51 -070026#include <linux/tracehook.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080027#include <linux/capability.h>
Nigel Cunningham7dfb7102006-12-06 20:34:23 -080028#include <linux/freezer.h>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080029#include <linux/pid_namespace.h>
30#include <linux/nsproxy.h>
Serge E. Hallyn6b550f92012-01-10 15:11:37 -080031#include <linux/user_namespace.h>
Srikar Dronamraju0326f5a2012-03-13 23:30:11 +053032#include <linux/uprobes.h>
Masami Hiramatsud1eb6502009-11-24 16:56:45 -050033#define CREATE_TRACE_POINTS
34#include <trace/events/signal.h>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080035
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <asm/param.h>
37#include <asm/uaccess.h>
38#include <asm/unistd.h>
39#include <asm/siginfo.h>
David Howellsd550bbd2012-03-28 18:30:03 +010040#include <asm/cacheflush.h>
Al Viroe1396062006-05-25 10:19:47 -040041#include "audit.h" /* audit_signal_info() */
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43/*
44 * SLAB caches for signal bits.
45 */
46
Christoph Lametere18b8902006-12-06 20:33:20 -080047static struct kmem_cache *sigqueue_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +090049int print_fatal_signals __read_mostly;
50
Roland McGrath35de2542008-07-25 19:45:51 -070051static void __user *sig_handler(struct task_struct *t, int sig)
Pavel Emelyanov93585ee2008-04-30 00:52:39 -070052{
Roland McGrath35de2542008-07-25 19:45:51 -070053 return t->sighand->action[sig - 1].sa.sa_handler;
54}
Pavel Emelyanov93585ee2008-04-30 00:52:39 -070055
Roland McGrath35de2542008-07-25 19:45:51 -070056static int sig_handler_ignored(void __user *handler, int sig)
57{
Pavel Emelyanov93585ee2008-04-30 00:52:39 -070058 /* Is it explicitly or implicitly ignored? */
Pavel Emelyanov93585ee2008-04-30 00:52:39 -070059 return handler == SIG_IGN ||
60 (handler == SIG_DFL && sig_kernel_ignore(sig));
61}
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
Oleg Nesterovdef8cf72012-03-23 15:02:45 -070063static int sig_task_ignored(struct task_struct *t, int sig, bool force)
Linus Torvalds1da177e2005-04-16 15:20:36 -070064{
Roland McGrath35de2542008-07-25 19:45:51 -070065 void __user *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
Oleg Nesterovf008faf2009-04-02 16:58:02 -070067 handler = sig_handler(t, sig);
68
69 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
Oleg Nesterovdef8cf72012-03-23 15:02:45 -070070 handler == SIG_DFL && !force)
Oleg Nesterovf008faf2009-04-02 16:58:02 -070071 return 1;
72
73 return sig_handler_ignored(handler, sig);
74}
75
Oleg Nesterovdef8cf72012-03-23 15:02:45 -070076static int sig_ignored(struct task_struct *t, int sig, bool force)
Oleg Nesterovf008faf2009-04-02 16:58:02 -070077{
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 /*
79 * Blocked signals are never ignored, since the
80 * signal handler may change by the time it is
81 * unblocked.
82 */
Roland McGrath325d22d2007-11-12 15:41:55 -080083 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 return 0;
85
Oleg Nesterovdef8cf72012-03-23 15:02:45 -070086 if (!sig_task_ignored(t, sig, force))
Roland McGrath35de2542008-07-25 19:45:51 -070087 return 0;
88
89 /*
90 * Tracers may want to know about even ignored signals.
91 */
Tejun Heoa288eec2011-06-17 16:50:37 +020092 return !t->ptrace;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093}
94
95/*
96 * Re-calculate pending state from the set of locally pending
97 * signals, globally pending signals, and blocked signals.
98 */
99static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
100{
101 unsigned long ready;
102 long i;
103
104 switch (_NSIG_WORDS) {
105 default:
106 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
107 ready |= signal->sig[i] &~ blocked->sig[i];
108 break;
109
110 case 4: ready = signal->sig[3] &~ blocked->sig[3];
111 ready |= signal->sig[2] &~ blocked->sig[2];
112 ready |= signal->sig[1] &~ blocked->sig[1];
113 ready |= signal->sig[0] &~ blocked->sig[0];
114 break;
115
116 case 2: ready = signal->sig[1] &~ blocked->sig[1];
117 ready |= signal->sig[0] &~ blocked->sig[0];
118 break;
119
120 case 1: ready = signal->sig[0] &~ blocked->sig[0];
121 }
122 return ready != 0;
123}
124
125#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
126
Roland McGrath7bb44ad2007-05-23 13:57:44 -0700127static int recalc_sigpending_tsk(struct task_struct *t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128{
Tejun Heo3759a0d2011-06-02 11:14:00 +0200129 if ((t->jobctl & JOBCTL_PENDING_MASK) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 PENDING(&t->pending, &t->blocked) ||
Roland McGrath7bb44ad2007-05-23 13:57:44 -0700131 PENDING(&t->signal->shared_pending, &t->blocked)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 set_tsk_thread_flag(t, TIF_SIGPENDING);
Roland McGrath7bb44ad2007-05-23 13:57:44 -0700133 return 1;
134 }
Roland McGrathb74d0de2007-06-06 03:59:00 -0700135 /*
136 * We must never clear the flag in another thread, or in current
137 * when it's possible the current syscall is returning -ERESTART*.
138 * So we don't clear it here, and only callers who know they should do.
139 */
Roland McGrath7bb44ad2007-05-23 13:57:44 -0700140 return 0;
141}
142
143/*
144 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
145 * This is superfluous when called on current, the wakeup is a harmless no-op.
146 */
147void recalc_sigpending_and_wake(struct task_struct *t)
148{
149 if (recalc_sigpending_tsk(t))
150 signal_wake_up(t, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151}
152
153void recalc_sigpending(void)
154{
Tejun Heodd1d6772011-06-02 11:14:00 +0200155 if (!recalc_sigpending_tsk(current) && !freezing(current))
Roland McGrathb74d0de2007-06-06 03:59:00 -0700156 clear_thread_flag(TIF_SIGPENDING);
157
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158}
159
160/* Given the mask, find the first available signal that should be serviced. */
161
Linus Torvaldsa27341c2010-03-02 08:36:46 -0800162#define SYNCHRONOUS_MASK \
163 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
Will Drewrya0727e82012-04-12 16:48:00 -0500164 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
Linus Torvaldsa27341c2010-03-02 08:36:46 -0800165
Davide Libenzifba2afa2007-05-10 22:23:13 -0700166int next_signal(struct sigpending *pending, sigset_t *mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167{
168 unsigned long i, *s, *m, x;
169 int sig = 0;
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +0900170
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 s = pending->signal.sig;
172 m = mask->sig;
Linus Torvaldsa27341c2010-03-02 08:36:46 -0800173
174 /*
175 * Handle the first word specially: it contains the
176 * synchronous signals that need to be dequeued first.
177 */
178 x = *s &~ *m;
179 if (x) {
180 if (x & SYNCHRONOUS_MASK)
181 x &= SYNCHRONOUS_MASK;
182 sig = ffz(~x) + 1;
183 return sig;
184 }
185
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 switch (_NSIG_WORDS) {
187 default:
Linus Torvaldsa27341c2010-03-02 08:36:46 -0800188 for (i = 1; i < _NSIG_WORDS; ++i) {
189 x = *++s &~ *++m;
190 if (!x)
191 continue;
192 sig = ffz(~x) + i*_NSIG_BPW + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 break;
Linus Torvaldsa27341c2010-03-02 08:36:46 -0800194 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 break;
196
Linus Torvaldsa27341c2010-03-02 08:36:46 -0800197 case 2:
198 x = s[1] &~ m[1];
199 if (!x)
200 break;
201 sig = ffz(~x) + _NSIG_BPW + 1;
202 break;
203
204 case 1:
205 /* Nothing to do */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 break;
207 }
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +0900208
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 return sig;
210}
211
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +0900212static inline void print_dropped_signal(int sig)
213{
214 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
215
216 if (!print_fatal_signals)
217 return;
218
219 if (!__ratelimit(&ratelimit_state))
220 return;
221
222 printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
223 current->comm, current->pid, sig);
224}
225
Tejun Heoe5c19022011-03-23 10:37:00 +0100226/**
Tejun Heo7dd3db52011-06-02 11:14:00 +0200227 * task_set_jobctl_pending - set jobctl pending bits
228 * @task: target task
229 * @mask: pending bits to set
230 *
231 * Clear @mask from @task->jobctl. @mask must be subset of
232 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
233 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
234 * cleared. If @task is already being killed or exiting, this function
235 * becomes noop.
236 *
237 * CONTEXT:
238 * Must be called with @task->sighand->siglock held.
239 *
240 * RETURNS:
241 * %true if @mask is set, %false if made noop because @task was dying.
242 */
243bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask)
244{
245 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
246 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
247 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
248
249 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
250 return false;
251
252 if (mask & JOBCTL_STOP_SIGMASK)
253 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
254
255 task->jobctl |= mask;
256 return true;
257}
258
259/**
Tejun Heoa8f072c2011-06-02 11:13:59 +0200260 * task_clear_jobctl_trapping - clear jobctl trapping bit
Tejun Heod79fdd62011-03-23 10:37:00 +0100261 * @task: target task
262 *
Tejun Heoa8f072c2011-06-02 11:13:59 +0200263 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
264 * Clear it and wake up the ptracer. Note that we don't need any further
265 * locking. @task->siglock guarantees that @task->parent points to the
266 * ptracer.
Tejun Heod79fdd62011-03-23 10:37:00 +0100267 *
268 * CONTEXT:
269 * Must be called with @task->sighand->siglock held.
270 */
Tejun Heo73ddff22011-06-14 11:20:14 +0200271void task_clear_jobctl_trapping(struct task_struct *task)
Tejun Heod79fdd62011-03-23 10:37:00 +0100272{
Tejun Heoa8f072c2011-06-02 11:13:59 +0200273 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
274 task->jobctl &= ~JOBCTL_TRAPPING;
Tejun Heo62c124f2011-06-02 11:14:00 +0200275 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
Tejun Heod79fdd62011-03-23 10:37:00 +0100276 }
277}
278
279/**
Tejun Heo3759a0d2011-06-02 11:14:00 +0200280 * task_clear_jobctl_pending - clear jobctl pending bits
Tejun Heoe5c19022011-03-23 10:37:00 +0100281 * @task: target task
Tejun Heo3759a0d2011-06-02 11:14:00 +0200282 * @mask: pending bits to clear
Tejun Heoe5c19022011-03-23 10:37:00 +0100283 *
Tejun Heo3759a0d2011-06-02 11:14:00 +0200284 * Clear @mask from @task->jobctl. @mask must be subset of
285 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
286 * STOP bits are cleared together.
Tejun Heoe5c19022011-03-23 10:37:00 +0100287 *
Tejun Heo6dfca322011-06-02 11:14:00 +0200288 * If clearing of @mask leaves no stop or trap pending, this function calls
289 * task_clear_jobctl_trapping().
Tejun Heoe5c19022011-03-23 10:37:00 +0100290 *
291 * CONTEXT:
292 * Must be called with @task->sighand->siglock held.
293 */
Tejun Heo3759a0d2011-06-02 11:14:00 +0200294void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask)
Tejun Heoe5c19022011-03-23 10:37:00 +0100295{
Tejun Heo3759a0d2011-06-02 11:14:00 +0200296 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
297
298 if (mask & JOBCTL_STOP_PENDING)
299 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
300
301 task->jobctl &= ~mask;
Tejun Heo6dfca322011-06-02 11:14:00 +0200302
303 if (!(task->jobctl & JOBCTL_PENDING_MASK))
304 task_clear_jobctl_trapping(task);
Tejun Heoe5c19022011-03-23 10:37:00 +0100305}
306
307/**
308 * task_participate_group_stop - participate in a group stop
309 * @task: task participating in a group stop
310 *
Tejun Heoa8f072c2011-06-02 11:13:59 +0200311 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
Tejun Heo39efa3e2011-03-23 10:37:00 +0100312 * Group stop states are cleared and the group stop count is consumed if
Tejun Heoa8f072c2011-06-02 11:13:59 +0200313 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
Tejun Heo39efa3e2011-03-23 10:37:00 +0100314 * stop, the appropriate %SIGNAL_* flags are set.
Tejun Heoe5c19022011-03-23 10:37:00 +0100315 *
316 * CONTEXT:
317 * Must be called with @task->sighand->siglock held.
Tejun Heo244056f2011-03-23 10:37:01 +0100318 *
319 * RETURNS:
320 * %true if group stop completion should be notified to the parent, %false
321 * otherwise.
Tejun Heoe5c19022011-03-23 10:37:00 +0100322 */
323static bool task_participate_group_stop(struct task_struct *task)
324{
325 struct signal_struct *sig = task->signal;
Tejun Heoa8f072c2011-06-02 11:13:59 +0200326 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
Tejun Heoe5c19022011-03-23 10:37:00 +0100327
Tejun Heoa8f072c2011-06-02 11:13:59 +0200328 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
Tejun Heo39efa3e2011-03-23 10:37:00 +0100329
Tejun Heo3759a0d2011-06-02 11:14:00 +0200330 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
Tejun Heoe5c19022011-03-23 10:37:00 +0100331
332 if (!consume)
333 return false;
334
335 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
336 sig->group_stop_count--;
337
Tejun Heo244056f2011-03-23 10:37:01 +0100338 /*
339 * Tell the caller to notify completion iff we are entering into a
340 * fresh group stop. Read comment in do_signal_stop() for details.
341 */
342 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
Tejun Heoe5c19022011-03-23 10:37:00 +0100343 sig->flags = SIGNAL_STOP_STOPPED;
344 return true;
345 }
346 return false;
347}
348
David Howellsc69e8d92008-11-14 10:39:19 +1100349/*
350 * allocate a new signal queue record
351 * - this may be called without locks if and only if t == current, otherwise an
Randy Dunlap5aba0852011-04-04 14:59:31 -0700352 * appropriate lock must be held to stop the target task from exiting
David Howellsc69e8d92008-11-14 10:39:19 +1100353 */
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +0900354static struct sigqueue *
355__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356{
357 struct sigqueue *q = NULL;
Linus Torvalds10b1fbd2006-11-04 13:03:00 -0800358 struct user_struct *user;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359
Linus Torvalds10b1fbd2006-11-04 13:03:00 -0800360 /*
Thomas Gleixner7cf7db82009-12-10 00:53:21 +0000361 * Protect access to @t credentials. This can go away when all
362 * callers hold rcu read lock.
Linus Torvalds10b1fbd2006-11-04 13:03:00 -0800363 */
Thomas Gleixner7cf7db82009-12-10 00:53:21 +0000364 rcu_read_lock();
David Howellsd84f4f92008-11-14 10:39:23 +1100365 user = get_uid(__task_cred(t)->user);
Linus Torvalds10b1fbd2006-11-04 13:03:00 -0800366 atomic_inc(&user->sigpending);
Thomas Gleixner7cf7db82009-12-10 00:53:21 +0000367 rcu_read_unlock();
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +0900368
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (override_rlimit ||
Linus Torvalds10b1fbd2006-11-04 13:03:00 -0800370 atomic_read(&user->sigpending) <=
Jiri Slaby78d7d402010-03-05 13:42:54 -0800371 task_rlimit(t, RLIMIT_SIGPENDING)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 q = kmem_cache_alloc(sigqueue_cachep, flags);
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +0900373 } else {
374 print_dropped_signal(sig);
375 }
376
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 if (unlikely(q == NULL)) {
Linus Torvalds10b1fbd2006-11-04 13:03:00 -0800378 atomic_dec(&user->sigpending);
David Howellsd84f4f92008-11-14 10:39:23 +1100379 free_uid(user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 } else {
381 INIT_LIST_HEAD(&q->list);
382 q->flags = 0;
David Howellsd84f4f92008-11-14 10:39:23 +1100383 q->user = user;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 }
David Howellsd84f4f92008-11-14 10:39:23 +1100385
386 return q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387}
388
Andrew Morton514a01b2006-02-03 03:04:41 -0800389static void __sigqueue_free(struct sigqueue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390{
391 if (q->flags & SIGQUEUE_PREALLOC)
392 return;
393 atomic_dec(&q->user->sigpending);
394 free_uid(q->user);
395 kmem_cache_free(sigqueue_cachep, q);
396}
397
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800398void flush_sigqueue(struct sigpending *queue)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399{
400 struct sigqueue *q;
401
402 sigemptyset(&queue->signal);
403 while (!list_empty(&queue->list)) {
404 q = list_entry(queue->list.next, struct sigqueue , list);
405 list_del_init(&q->list);
406 __sigqueue_free(q);
407 }
408}
409
410/*
411 * Flush all pending signals for a task.
412 */
David Howells3bcac022009-04-29 13:45:05 +0100413void __flush_signals(struct task_struct *t)
414{
415 clear_tsk_thread_flag(t, TIF_SIGPENDING);
416 flush_sigqueue(&t->pending);
417 flush_sigqueue(&t->signal->shared_pending);
418}
419
Oleg Nesterovc81addc2006-03-28 16:11:17 -0800420void flush_signals(struct task_struct *t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421{
422 unsigned long flags;
423
424 spin_lock_irqsave(&t->sighand->siglock, flags);
David Howells3bcac022009-04-29 13:45:05 +0100425 __flush_signals(t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 spin_unlock_irqrestore(&t->sighand->siglock, flags);
427}
428
Oleg Nesterovcbaffba2008-05-26 20:55:42 +0400429static void __flush_itimer_signals(struct sigpending *pending)
430{
431 sigset_t signal, retain;
432 struct sigqueue *q, *n;
433
434 signal = pending->signal;
435 sigemptyset(&retain);
436
437 list_for_each_entry_safe(q, n, &pending->list, list) {
438 int sig = q->info.si_signo;
439
440 if (likely(q->info.si_code != SI_TIMER)) {
441 sigaddset(&retain, sig);
442 } else {
443 sigdelset(&signal, sig);
444 list_del_init(&q->list);
445 __sigqueue_free(q);
446 }
447 }
448
449 sigorsets(&pending->signal, &signal, &retain);
450}
451
452void flush_itimer_signals(void)
453{
454 struct task_struct *tsk = current;
455 unsigned long flags;
456
457 spin_lock_irqsave(&tsk->sighand->siglock, flags);
458 __flush_itimer_signals(&tsk->pending);
459 __flush_itimer_signals(&tsk->signal->shared_pending);
460 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
461}
462
Oleg Nesterov10ab8252007-05-09 02:34:37 -0700463void ignore_signals(struct task_struct *t)
464{
465 int i;
466
467 for (i = 0; i < _NSIG; ++i)
468 t->sighand->action[i].sa.sa_handler = SIG_IGN;
469
470 flush_signals(t);
471}
472
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 * Flush all handlers for a task.
475 */
476
477void
478flush_signal_handlers(struct task_struct *t, int force_default)
479{
480 int i;
481 struct k_sigaction *ka = &t->sighand->action[0];
482 for (i = _NSIG ; i != 0 ; i--) {
483 if (force_default || ka->sa.sa_handler != SIG_IGN)
484 ka->sa.sa_handler = SIG_DFL;
485 ka->sa.sa_flags = 0;
486 sigemptyset(&ka->sa.sa_mask);
487 ka++;
488 }
489}
490
Masoud Asgharifard Sharbianiabd4f752007-07-22 11:12:28 +0200491int unhandled_signal(struct task_struct *tsk, int sig)
492{
Roland McGrath445a91d2008-07-25 19:45:52 -0700493 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
Serge E. Hallynb460cbc2007-10-18 23:39:52 -0700494 if (is_global_init(tsk))
Masoud Asgharifard Sharbianiabd4f752007-07-22 11:12:28 +0200495 return 1;
Roland McGrath445a91d2008-07-25 19:45:52 -0700496 if (handler != SIG_IGN && handler != SIG_DFL)
Masoud Asgharifard Sharbianiabd4f752007-07-22 11:12:28 +0200497 return 0;
Tejun Heoa288eec2011-06-17 16:50:37 +0200498 /* if ptraced, let the tracer determine */
499 return !tsk->ptrace;
Masoud Asgharifard Sharbianiabd4f752007-07-22 11:12:28 +0200500}
501
Randy Dunlap5aba0852011-04-04 14:59:31 -0700502/*
503 * Notify the system that a driver wants to block all signals for this
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 * process, and wants to be notified if any signals at all were to be
505 * sent/acted upon. If the notifier routine returns non-zero, then the
506 * signal will be acted upon after all. If the notifier routine returns 0,
507 * then then signal will be blocked. Only one block per process is
508 * allowed. priv is a pointer to private data that the notifier routine
Randy Dunlap5aba0852011-04-04 14:59:31 -0700509 * can use to determine if the signal should be blocked or not.
510 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511void
512block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
513{
514 unsigned long flags;
515
516 spin_lock_irqsave(&current->sighand->siglock, flags);
517 current->notifier_mask = mask;
518 current->notifier_data = priv;
519 current->notifier = notifier;
520 spin_unlock_irqrestore(&current->sighand->siglock, flags);
521}
522
523/* Notify the system that blocking has ended. */
524
525void
526unblock_all_signals(void)
527{
528 unsigned long flags;
529
530 spin_lock_irqsave(&current->sighand->siglock, flags);
531 current->notifier = NULL;
532 current->notifier_data = NULL;
533 recalc_sigpending();
534 spin_unlock_irqrestore(&current->sighand->siglock, flags);
535}
536
Oleg Nesterov100360f2008-07-25 01:47:29 -0700537static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538{
539 struct sigqueue *q, *first = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 /*
542 * Collect the siginfo appropriate to this signal. Check if
543 * there is another siginfo for the same signal.
544 */
545 list_for_each_entry(q, &list->list, list) {
546 if (q->info.si_signo == sig) {
Oleg Nesterovd4434202008-07-25 01:47:28 -0700547 if (first)
548 goto still_pending;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 first = q;
550 }
551 }
Oleg Nesterovd4434202008-07-25 01:47:28 -0700552
553 sigdelset(&list->signal, sig);
554
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 if (first) {
Oleg Nesterovd4434202008-07-25 01:47:28 -0700556still_pending:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 list_del_init(&first->list);
558 copy_siginfo(info, &first->info);
559 __sigqueue_free(first);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 } else {
Randy Dunlap5aba0852011-04-04 14:59:31 -0700561 /*
562 * Ok, it wasn't in the queue. This must be
563 * a fast-pathed signal or we must have been
564 * out of queue space. So zero out the info.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 info->si_signo = sig;
567 info->si_errno = 0;
Oleg Nesterov7486e5d2009-12-15 16:47:24 -0800568 info->si_code = SI_USER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 info->si_pid = 0;
570 info->si_uid = 0;
571 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572}
573
574static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
575 siginfo_t *info)
576{
Roland McGrath27d91e02006-09-29 02:00:31 -0700577 int sig = next_signal(pending, mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 if (sig) {
580 if (current->notifier) {
581 if (sigismember(current->notifier_mask, sig)) {
582 if (!(current->notifier)(current->notifier_data)) {
583 clear_thread_flag(TIF_SIGPENDING);
584 return 0;
585 }
586 }
587 }
588
Oleg Nesterov100360f2008-07-25 01:47:29 -0700589 collect_signal(sig, pending, info);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591
592 return sig;
593}
594
595/*
Randy Dunlap5aba0852011-04-04 14:59:31 -0700596 * Dequeue a signal and return the element to the caller, which is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 * expected to free it.
598 *
599 * All callers have to hold the siglock.
600 */
601int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
602{
Pavel Emelyanovc5363d02008-04-30 00:52:40 -0700603 int signr;
Benjamin Herrenschmidtcaec4e82007-06-12 08:16:18 +1000604
605 /* We only dequeue private signals from ourselves, we don't let
606 * signalfd steal them
607 */
Davide Libenzib8fceee2007-09-20 12:40:16 -0700608 signr = __dequeue_signal(&tsk->pending, mask, info);
Thomas Gleixner8bfd9a72007-02-16 01:28:12 -0800609 if (!signr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 signr = __dequeue_signal(&tsk->signal->shared_pending,
611 mask, info);
Thomas Gleixner8bfd9a72007-02-16 01:28:12 -0800612 /*
613 * itimer signal ?
614 *
615 * itimers are process shared and we restart periodic
616 * itimers in the signal delivery path to prevent DoS
617 * attacks in the high resolution timer case. This is
Randy Dunlap5aba0852011-04-04 14:59:31 -0700618 * compliant with the old way of self-restarting
Thomas Gleixner8bfd9a72007-02-16 01:28:12 -0800619 * itimers, as the SIGALRM is a legacy signal and only
620 * queued once. Changing the restart behaviour to
621 * restart the timer in the signal dequeue path is
622 * reducing the timer noise on heavy loaded !highres
623 * systems too.
624 */
625 if (unlikely(signr == SIGALRM)) {
626 struct hrtimer *tmr = &tsk->signal->real_timer;
627
628 if (!hrtimer_is_queued(tmr) &&
629 tsk->signal->it_real_incr.tv64 != 0) {
630 hrtimer_forward(tmr, tmr->base->get_time(),
631 tsk->signal->it_real_incr);
632 hrtimer_restart(tmr);
633 }
634 }
635 }
Pavel Emelyanovc5363d02008-04-30 00:52:40 -0700636
Davide Libenzib8fceee2007-09-20 12:40:16 -0700637 recalc_sigpending();
Pavel Emelyanovc5363d02008-04-30 00:52:40 -0700638 if (!signr)
639 return 0;
640
641 if (unlikely(sig_kernel_stop(signr))) {
Thomas Gleixner8bfd9a72007-02-16 01:28:12 -0800642 /*
643 * Set a marker that we have dequeued a stop signal. Our
644 * caller might release the siglock and then the pending
645 * stop signal it is about to process is no longer in the
646 * pending bitmasks, but must still be cleared by a SIGCONT
647 * (and overruled by a SIGKILL). So those cases clear this
648 * shared flag after we've set it. Note that this flag may
649 * remain set after the signal we return is ignored or
650 * handled. That doesn't matter because its only purpose
651 * is to alert stop-signal processing code when another
652 * processor has come along and cleared the flag.
653 */
Tejun Heoa8f072c2011-06-02 11:13:59 +0200654 current->jobctl |= JOBCTL_STOP_DEQUEUED;
Thomas Gleixner8bfd9a72007-02-16 01:28:12 -0800655 }
Pavel Emelyanovc5363d02008-04-30 00:52:40 -0700656 if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 /*
658 * Release the siglock to ensure proper locking order
659 * of timer locks outside of siglocks. Note, we leave
660 * irqs disabled here, since the posix-timers code is
661 * about to disable them again anyway.
662 */
663 spin_unlock(&tsk->sighand->siglock);
664 do_schedule_next_timer(info);
665 spin_lock(&tsk->sighand->siglock);
666 }
667 return signr;
668}
669
670/*
671 * Tell a process that it has a new active signal..
672 *
673 * NOTE! we rely on the previous spin_lock to
674 * lock interrupts for us! We can only be called with
675 * "siglock" held, and the local interrupt must
676 * have been disabled when that got acquired!
677 *
678 * No need to set need_resched since signal event passing
679 * goes through ->blocked
680 */
681void signal_wake_up(struct task_struct *t, int resume)
682{
683 unsigned int mask;
684
685 set_tsk_thread_flag(t, TIF_SIGPENDING);
686
687 /*
Matthew Wilcoxf021a3c2007-12-06 11:13:16 -0500688 * For SIGKILL, we want to wake it up in the stopped/traced/killable
689 * case. We don't check t->state here because there is a race with it
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 * executing another processor and just now entering stopped state.
691 * By using wake_up_state, we ensure the process will wake up and
692 * handle its death signal.
693 */
694 mask = TASK_INTERRUPTIBLE;
695 if (resume)
Matthew Wilcoxf021a3c2007-12-06 11:13:16 -0500696 mask |= TASK_WAKEKILL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 if (!wake_up_state(t, mask))
698 kick_process(t);
699}
700
701/*
702 * Remove signals in mask from the pending set and queue.
703 * Returns 1 if any signals were found.
704 *
705 * All callers must be holding the siglock.
George Anzinger71fabd52006-01-08 01:02:48 -0800706 *
707 * This version takes a sigset mask and looks at all signals,
708 * not just those in the first mask word.
709 */
710static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
711{
712 struct sigqueue *q, *n;
713 sigset_t m;
714
715 sigandsets(&m, mask, &s->signal);
716 if (sigisemptyset(&m))
717 return 0;
718
Oleg Nesterov702a5072011-04-27 22:01:27 +0200719 sigandnsets(&s->signal, &s->signal, mask);
George Anzinger71fabd52006-01-08 01:02:48 -0800720 list_for_each_entry_safe(q, n, &s->list, list) {
721 if (sigismember(mask, q->info.si_signo)) {
722 list_del_init(&q->list);
723 __sigqueue_free(q);
724 }
725 }
726 return 1;
727}
728/*
729 * Remove signals in mask from the pending set and queue.
730 * Returns 1 if any signals were found.
731 *
732 * All callers must be holding the siglock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 */
734static int rm_from_queue(unsigned long mask, struct sigpending *s)
735{
736 struct sigqueue *q, *n;
737
738 if (!sigtestsetmask(&s->signal, mask))
739 return 0;
740
741 sigdelsetmask(&s->signal, mask);
742 list_for_each_entry_safe(q, n, &s->list, list) {
743 if (q->info.si_signo < SIGRTMIN &&
744 (mask & sigmask(q->info.si_signo))) {
745 list_del_init(&q->list);
746 __sigqueue_free(q);
747 }
748 }
749 return 1;
750}
751
Oleg Nesterov614c5172009-12-15 16:47:22 -0800752static inline int is_si_special(const struct siginfo *info)
753{
754 return info <= SEND_SIG_FORCED;
755}
756
757static inline bool si_fromuser(const struct siginfo *info)
758{
759 return info == SEND_SIG_NOINFO ||
760 (!is_si_special(info) && SI_FROMUSER(info));
761}
762
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763/*
Serge E. Hallyn39fd3392011-03-23 16:43:19 -0700764 * called with RCU read lock from check_kill_permission()
765 */
766static int kill_ok_by_cred(struct task_struct *t)
767{
768 const struct cred *cred = current_cred();
769 const struct cred *tcred = __task_cred(t);
770
Eric W. Biederman5af66202012-03-03 20:21:47 -0800771 if (uid_eq(cred->euid, tcred->suid) ||
772 uid_eq(cred->euid, tcred->uid) ||
773 uid_eq(cred->uid, tcred->suid) ||
774 uid_eq(cred->uid, tcred->uid))
Serge E. Hallyn39fd3392011-03-23 16:43:19 -0700775 return 1;
776
Eric W. Biedermanc4a4d602011-11-16 23:15:31 -0800777 if (ns_capable(tcred->user_ns, CAP_KILL))
Serge E. Hallyn39fd3392011-03-23 16:43:19 -0700778 return 1;
779
780 return 0;
781}
782
783/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 * Bad permissions for sending the signal
David Howells694f6902010-08-04 16:59:14 +0100785 * - the caller must hold the RCU read lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 */
787static int check_kill_permission(int sig, struct siginfo *info,
788 struct task_struct *t)
789{
Oleg Nesterov2e2ba222008-04-30 00:53:01 -0700790 struct pid *sid;
Oleg Nesterov3b5e9e52008-04-30 00:52:42 -0700791 int error;
792
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700793 if (!valid_signal(sig))
Oleg Nesterov3b5e9e52008-04-30 00:52:42 -0700794 return -EINVAL;
795
Oleg Nesterov614c5172009-12-15 16:47:22 -0800796 if (!si_fromuser(info))
Oleg Nesterov3b5e9e52008-04-30 00:52:42 -0700797 return 0;
798
799 error = audit_signal_info(sig, t); /* Let audit system see the signal */
800 if (error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 return error;
Amy Griffise54dc242007-03-29 18:01:04 -0400802
Oleg Nesterov065add32010-05-26 14:42:54 -0700803 if (!same_thread_group(current, t) &&
Serge E. Hallyn39fd3392011-03-23 16:43:19 -0700804 !kill_ok_by_cred(t)) {
Oleg Nesterov2e2ba222008-04-30 00:53:01 -0700805 switch (sig) {
806 case SIGCONT:
Oleg Nesterov2e2ba222008-04-30 00:53:01 -0700807 sid = task_session(t);
Oleg Nesterov2e2ba222008-04-30 00:53:01 -0700808 /*
809 * We don't return the error if sid == NULL. The
810 * task was unhashed, the caller must notice this.
811 */
812 if (!sid || sid == task_session(current))
813 break;
814 default:
815 return -EPERM;
816 }
817 }
Steve Grubbc2f0c7c2005-05-06 12:38:39 +0100818
Amy Griffise54dc242007-03-29 18:01:04 -0400819 return security_task_kill(t, info, sig, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820}
821
Tejun Heofb1d9102011-06-14 11:20:17 +0200822/**
823 * ptrace_trap_notify - schedule trap to notify ptracer
824 * @t: tracee wanting to notify tracer
825 *
826 * This function schedules sticky ptrace trap which is cleared on the next
827 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
828 * ptracer.
829 *
Tejun Heo544b2c92011-06-14 11:20:18 +0200830 * If @t is running, STOP trap will be taken. If trapped for STOP and
831 * ptracer is listening for events, tracee is woken up so that it can
832 * re-trap for the new event. If trapped otherwise, STOP trap will be
833 * eventually taken without returning to userland after the existing traps
834 * are finished by PTRACE_CONT.
Tejun Heofb1d9102011-06-14 11:20:17 +0200835 *
836 * CONTEXT:
837 * Must be called with @task->sighand->siglock held.
838 */
839static void ptrace_trap_notify(struct task_struct *t)
840{
841 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
842 assert_spin_locked(&t->sighand->siglock);
843
844 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
Tejun Heo544b2c92011-06-14 11:20:18 +0200845 signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
Tejun Heofb1d9102011-06-14 11:20:17 +0200846}
847
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848/*
Oleg Nesterov7e695a52008-04-30 00:52:59 -0700849 * Handle magic process-wide effects of stop/continue signals. Unlike
850 * the signal actions, these happen immediately at signal-generation
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 * time regardless of blocking, ignoring, or handling. This does the
852 * actual continuing for SIGCONT, but not the actual stopping for stop
Oleg Nesterov7e695a52008-04-30 00:52:59 -0700853 * signals. The process stop is done as a signal action for SIG_DFL.
854 *
855 * Returns true if the signal should be actually delivered, otherwise
856 * it should be dropped.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 */
Oleg Nesterovdef8cf72012-03-23 15:02:45 -0700858static int prepare_signal(int sig, struct task_struct *p, bool force)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859{
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700860 struct signal_struct *signal = p->signal;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 struct task_struct *t;
862
Oleg Nesterov7e695a52008-04-30 00:52:59 -0700863 if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 /*
Oleg Nesterov7e695a52008-04-30 00:52:59 -0700865 * The process is in the middle of dying, nothing to do.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 */
Oleg Nesterov7e695a52008-04-30 00:52:59 -0700867 } else if (sig_kernel_stop(sig)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 /*
869 * This is a stop signal. Remove SIGCONT from all queues.
870 */
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700871 rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 t = p;
873 do {
874 rm_from_queue(sigmask(SIGCONT), &t->pending);
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700875 } while_each_thread(p, t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 } else if (sig == SIGCONT) {
Oleg Nesterovfc321d22008-04-30 00:52:46 -0700877 unsigned int why;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 /*
Oleg Nesterov1deac632011-04-01 20:11:50 +0200879 * Remove all stop signals from all queues, wake all threads.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 */
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700881 rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 t = p;
883 do {
Tejun Heo3759a0d2011-06-02 11:14:00 +0200884 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
Tejun Heofb1d9102011-06-14 11:20:17 +0200886 if (likely(!(t->ptrace & PT_SEIZED)))
887 wake_up_state(t, __TASK_STOPPED);
888 else
889 ptrace_trap_notify(t);
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700890 } while_each_thread(p, t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891
Oleg Nesterovfc321d22008-04-30 00:52:46 -0700892 /*
893 * Notify the parent with CLD_CONTINUED if we were stopped.
894 *
895 * If we were in the middle of a group stop, we pretend it
896 * was already finished, and then continued. Since SIGCHLD
897 * doesn't queue we report only CLD_STOPPED, as if the next
898 * CLD_CONTINUED was dropped.
899 */
900 why = 0;
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700901 if (signal->flags & SIGNAL_STOP_STOPPED)
Oleg Nesterovfc321d22008-04-30 00:52:46 -0700902 why |= SIGNAL_CLD_CONTINUED;
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700903 else if (signal->group_stop_count)
Oleg Nesterovfc321d22008-04-30 00:52:46 -0700904 why |= SIGNAL_CLD_STOPPED;
905
906 if (why) {
Oleg Nesterov021e1ae2008-04-30 00:53:00 -0700907 /*
Roland McGrathae6d2ed2009-09-23 15:56:53 -0700908 * The first thread which returns from do_signal_stop()
Oleg Nesterov021e1ae2008-04-30 00:53:00 -0700909 * will take ->siglock, notice SIGNAL_CLD_MASK, and
910 * notify its parent. See get_signal_to_deliver().
911 */
Oleg Nesterovad16a4602008-04-30 00:52:46 -0700912 signal->flags = why | SIGNAL_STOP_CONTINUED;
913 signal->group_stop_count = 0;
914 signal->group_exit_code = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 }
Oleg Nesterov7e695a52008-04-30 00:52:59 -0700917
Oleg Nesterovdef8cf72012-03-23 15:02:45 -0700918 return !sig_ignored(p, sig, force);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919}
920
Oleg Nesterov71f11dc2008-04-30 00:52:53 -0700921/*
922 * Test if P wants to take SIG. After we've checked all threads with this,
923 * it's equivalent to finding no threads not blocking SIG. Any threads not
924 * blocking SIG were ruled out because they are not running and already
925 * have pending signals. Such threads will dequeue from the shared queue
926 * as soon as they're available, so putting the signal on the shared queue
927 * will be equivalent to sending it to one such thread.
928 */
929static inline int wants_signal(int sig, struct task_struct *p)
930{
931 if (sigismember(&p->blocked, sig))
932 return 0;
933 if (p->flags & PF_EXITING)
934 return 0;
935 if (sig == SIGKILL)
936 return 1;
937 if (task_is_stopped_or_traced(p))
938 return 0;
939 return task_curr(p) || !signal_pending(p);
940}
941
Oleg Nesterov5fcd8352008-04-30 00:52:55 -0700942static void complete_signal(int sig, struct task_struct *p, int group)
Oleg Nesterov71f11dc2008-04-30 00:52:53 -0700943{
944 struct signal_struct *signal = p->signal;
945 struct task_struct *t;
946
947 /*
948 * Now find a thread we can wake up to take the signal off the queue.
949 *
950 * If the main thread wants the signal, it gets first crack.
951 * Probably the least surprising to the average bear.
952 */
953 if (wants_signal(sig, p))
954 t = p;
Oleg Nesterov5fcd8352008-04-30 00:52:55 -0700955 else if (!group || thread_group_empty(p))
Oleg Nesterov71f11dc2008-04-30 00:52:53 -0700956 /*
957 * There is just one thread and it does not need to be woken.
958 * It will dequeue unblocked signals before it runs again.
959 */
960 return;
961 else {
962 /*
963 * Otherwise try to find a suitable thread.
964 */
965 t = signal->curr_target;
966 while (!wants_signal(sig, t)) {
967 t = next_thread(t);
968 if (t == signal->curr_target)
969 /*
970 * No thread needs to be woken.
971 * Any eligible threads will see
972 * the signal in the queue soon.
973 */
974 return;
975 }
976 signal->curr_target = t;
977 }
978
979 /*
980 * Found a killable thread. If the signal will be fatal,
981 * then start taking the whole group down immediately.
982 */
Oleg Nesterovfae5fa42008-04-30 00:53:03 -0700983 if (sig_fatal(p, sig) &&
984 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
Oleg Nesterov71f11dc2008-04-30 00:52:53 -0700985 !sigismember(&t->real_blocked, sig) &&
Tejun Heoa288eec2011-06-17 16:50:37 +0200986 (sig == SIGKILL || !t->ptrace)) {
Oleg Nesterov71f11dc2008-04-30 00:52:53 -0700987 /*
988 * This signal will be fatal to the whole group.
989 */
990 if (!sig_kernel_coredump(sig)) {
991 /*
992 * Start a group exit and wake everybody up.
993 * This way we don't have other threads
994 * running and doing things after a slower
995 * thread has the fatal signal pending.
996 */
997 signal->flags = SIGNAL_GROUP_EXIT;
998 signal->group_exit_code = sig;
999 signal->group_stop_count = 0;
1000 t = p;
1001 do {
Tejun Heo6dfca322011-06-02 11:14:00 +02001002 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
Oleg Nesterov71f11dc2008-04-30 00:52:53 -07001003 sigaddset(&t->pending.signal, SIGKILL);
1004 signal_wake_up(t, 1);
1005 } while_each_thread(p, t);
1006 return;
1007 }
1008 }
1009
1010 /*
1011 * The signal is already in the shared-pending queue.
1012 * Tell the chosen thread to wake up and dequeue it.
1013 */
1014 signal_wake_up(t, sig == SIGKILL);
1015 return;
1016}
1017
Pavel Emelyanovaf7fff92008-04-30 00:52:34 -07001018static inline int legacy_queue(struct sigpending *signals, int sig)
1019{
1020 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1021}
1022
Serge E. Hallyn6b550f92012-01-10 15:11:37 -08001023#ifdef CONFIG_USER_NS
1024static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1025{
1026 if (current_user_ns() == task_cred_xxx(t, user_ns))
1027 return;
1028
1029 if (SI_FROMKERNEL(info))
1030 return;
1031
Eric W. Biederman078de5f2012-02-08 07:00:08 -08001032 rcu_read_lock();
1033 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
1034 make_kuid(current_user_ns(), info->si_uid));
1035 rcu_read_unlock();
Serge E. Hallyn6b550f92012-01-10 15:11:37 -08001036}
1037#else
1038static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
1039{
1040 return;
1041}
1042#endif
1043
Sukadev Bhattiprolu7978b562009-04-02 16:58:04 -07001044static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
1045 int group, int from_ancestor_ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046{
Oleg Nesterov2ca35152008-04-30 00:52:54 -07001047 struct sigpending *pending;
Oleg Nesterov6e65acb2008-04-30 00:52:50 -07001048 struct sigqueue *q;
Vegard Nossum7a0aeb12009-05-16 11:28:33 +02001049 int override_rlimit;
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001050 int ret = 0, result;
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -04001051
Oleg Nesterov6e65acb2008-04-30 00:52:50 -07001052 assert_spin_locked(&t->sighand->siglock);
Sukadev Bhattiprolu921cf9f2009-04-02 16:58:05 -07001053
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001054 result = TRACE_SIGNAL_IGNORED;
Oleg Nesterov629d3622012-03-23 15:02:44 -07001055 if (!prepare_signal(sig, t,
1056 from_ancestor_ns || (info == SEND_SIG_FORCED)))
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001057 goto ret;
Oleg Nesterov2ca35152008-04-30 00:52:54 -07001058
1059 pending = group ? &t->signal->shared_pending : &t->pending;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 /*
Pavel Emelyanov2acb0242008-04-30 00:52:35 -07001061 * Short-circuit ignored signals and support queuing
1062 * exactly one non-rt signal, so that we can get more
1063 * detailed information about the cause of the signal.
1064 */
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001065 result = TRACE_SIGNAL_ALREADY_PENDING;
Oleg Nesterov7e695a52008-04-30 00:52:59 -07001066 if (legacy_queue(pending, sig))
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001067 goto ret;
1068
1069 result = TRACE_SIGNAL_DELIVERED;
Davide Libenzifba2afa2007-05-10 22:23:13 -07001070 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071 * fast-pathed signals for kernel-internal things like SIGSTOP
1072 * or SIGKILL.
1073 */
Oleg Nesterovb67a1b92005-10-30 15:03:44 -08001074 if (info == SEND_SIG_FORCED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075 goto out_set;
1076
Randy Dunlap5aba0852011-04-04 14:59:31 -07001077 /*
1078 * Real-time signals must be queued if sent by sigqueue, or
1079 * some other real-time mechanism. It is implementation
1080 * defined whether kill() does so. We attempt to do so, on
1081 * the principle of least surprise, but since kill is not
1082 * allowed to fail with EAGAIN when low on memory we just
1083 * make sure at least one signal gets delivered and don't
1084 * pass on the info struct.
1085 */
Vegard Nossum7a0aeb12009-05-16 11:28:33 +02001086 if (sig < SIGRTMIN)
1087 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1088 else
1089 override_rlimit = 0;
1090
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +09001091 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
Vegard Nossum7a0aeb12009-05-16 11:28:33 +02001092 override_rlimit);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 if (q) {
Oleg Nesterov2ca35152008-04-30 00:52:54 -07001094 list_add_tail(&q->list, &pending->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 switch ((unsigned long) info) {
Oleg Nesterovb67a1b92005-10-30 15:03:44 -08001096 case (unsigned long) SEND_SIG_NOINFO:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 q->info.si_signo = sig;
1098 q->info.si_errno = 0;
1099 q->info.si_code = SI_USER;
Sukadev Bhattiprolu9cd4fd12009-01-06 14:42:46 -08001100 q->info.si_pid = task_tgid_nr_ns(current,
Sukadev Bhattiprolu09bca052009-01-06 14:42:45 -08001101 task_active_pid_ns(t));
Eric W. Biederman078de5f2012-02-08 07:00:08 -08001102 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 break;
Oleg Nesterovb67a1b92005-10-30 15:03:44 -08001104 case (unsigned long) SEND_SIG_PRIV:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 q->info.si_signo = sig;
1106 q->info.si_errno = 0;
1107 q->info.si_code = SI_KERNEL;
1108 q->info.si_pid = 0;
1109 q->info.si_uid = 0;
1110 break;
1111 default:
1112 copy_siginfo(&q->info, info);
Sukadev Bhattiprolu6588c1e2009-04-02 16:58:09 -07001113 if (from_ancestor_ns)
1114 q->info.si_pid = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115 break;
1116 }
Serge E. Hallyn6b550f92012-01-10 15:11:37 -08001117
1118 userns_fixup_signal_uid(&q->info, t);
1119
Oleg Nesterov621d3122005-10-30 15:03:45 -08001120 } else if (!is_si_special(info)) {
Masami Hiramatsuba005e12009-11-24 16:56:58 -05001121 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1122 /*
1123 * Queue overflow, abort. We may abort if the
1124 * signal was rt and sent by user using something
1125 * other than kill().
1126 */
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001127 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1128 ret = -EAGAIN;
1129 goto ret;
Masami Hiramatsuba005e12009-11-24 16:56:58 -05001130 } else {
1131 /*
1132 * This is a silent loss of information. We still
1133 * send the signal, but the *info bits are lost.
1134 */
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001135 result = TRACE_SIGNAL_LOSE_INFO;
Masami Hiramatsuba005e12009-11-24 16:56:58 -05001136 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 }
1138
1139out_set:
Oleg Nesterov53c30332008-04-30 00:53:00 -07001140 signalfd_notify(t, sig);
Oleg Nesterov2ca35152008-04-30 00:52:54 -07001141 sigaddset(&pending->signal, sig);
Pavel Emelyanov4cd4b6d2008-04-30 00:52:55 -07001142 complete_signal(sig, t, group);
Oleg Nesterov6c303d32011-11-22 21:13:48 +01001143ret:
1144 trace_signal_generate(sig, info, t, group, result);
1145 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146}
1147
Sukadev Bhattiprolu7978b562009-04-02 16:58:04 -07001148static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
1149 int group)
1150{
Sukadev Bhattiprolu921cf9f2009-04-02 16:58:05 -07001151 int from_ancestor_ns = 0;
1152
1153#ifdef CONFIG_PID_NS
Oleg Nesterovdd342002009-12-15 16:47:24 -08001154 from_ancestor_ns = si_fromuser(info) &&
1155 !task_pid_nr_ns(current, task_active_pid_ns(t));
Sukadev Bhattiprolu921cf9f2009-04-02 16:58:05 -07001156#endif
1157
1158 return __send_signal(sig, info, t, group, from_ancestor_ns);
Sukadev Bhattiprolu7978b562009-04-02 16:58:04 -07001159}
1160
Ingo Molnar45807a12007-07-15 23:40:10 -07001161static void print_fatal_signal(struct pt_regs *regs, int signr)
1162{
1163 printk("%s/%d: potentially unexpected fatal signal %d.\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001164 current->comm, task_pid_nr(current), signr);
Ingo Molnar45807a12007-07-15 23:40:10 -07001165
Al Viroca5cd872007-10-29 04:31:16 +00001166#if defined(__i386__) && !defined(__arch_um__)
H. Peter Anvin65ea5b02008-01-30 13:30:56 +01001167 printk("code at %08lx: ", regs->ip);
Ingo Molnar45807a12007-07-15 23:40:10 -07001168 {
1169 int i;
1170 for (i = 0; i < 16; i++) {
1171 unsigned char insn;
1172
Andi Kleenb45c6e72010-01-08 14:42:52 -08001173 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1174 break;
Ingo Molnar45807a12007-07-15 23:40:10 -07001175 printk("%02x ", insn);
1176 }
1177 }
1178#endif
1179 printk("\n");
Ed Swierk3a9f84d2009-01-26 15:33:31 -08001180 preempt_disable();
Ingo Molnar45807a12007-07-15 23:40:10 -07001181 show_regs(regs);
Ed Swierk3a9f84d2009-01-26 15:33:31 -08001182 preempt_enable();
Ingo Molnar45807a12007-07-15 23:40:10 -07001183}
1184
1185static int __init setup_print_fatal_signals(char *str)
1186{
1187 get_option (&str, &print_fatal_signals);
1188
1189 return 1;
1190}
1191
1192__setup("print-fatal-signals=", setup_print_fatal_signals);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193
Pavel Emelyanov4cd4b6d2008-04-30 00:52:55 -07001194int
1195__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1196{
1197 return send_signal(sig, info, p, 1);
1198}
1199
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200static int
1201specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1202{
Pavel Emelyanov4cd4b6d2008-04-30 00:52:55 -07001203 return send_signal(sig, info, t, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204}
1205
Oleg Nesterov4a30deb2009-09-23 15:57:00 -07001206int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1207 bool group)
1208{
1209 unsigned long flags;
1210 int ret = -ESRCH;
1211
1212 if (lock_task_sighand(p, &flags)) {
1213 ret = send_signal(sig, info, p, group);
1214 unlock_task_sighand(p, &flags);
1215 }
1216
1217 return ret;
1218}
1219
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220/*
1221 * Force a signal that the process can't ignore: if necessary
1222 * we unblock the signal and change any SIG_IGN to SIG_DFL.
Linus Torvaldsae74c3b2006-08-02 20:17:49 -07001223 *
1224 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1225 * since we do not want to have a signal handler that was blocked
1226 * be invoked when user space had explicitly blocked it.
1227 *
Oleg Nesterov80fe7282008-04-30 00:53:05 -07001228 * We don't want to have recursive SIGSEGV's etc, for example,
1229 * that is why we also clear SIGNAL_UNKILLABLE.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231int
1232force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1233{
1234 unsigned long int flags;
Linus Torvaldsae74c3b2006-08-02 20:17:49 -07001235 int ret, blocked, ignored;
1236 struct k_sigaction *action;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237
1238 spin_lock_irqsave(&t->sighand->siglock, flags);
Linus Torvaldsae74c3b2006-08-02 20:17:49 -07001239 action = &t->sighand->action[sig-1];
1240 ignored = action->sa.sa_handler == SIG_IGN;
1241 blocked = sigismember(&t->blocked, sig);
1242 if (blocked || ignored) {
1243 action->sa.sa_handler = SIG_DFL;
1244 if (blocked) {
1245 sigdelset(&t->blocked, sig);
Roland McGrath7bb44ad2007-05-23 13:57:44 -07001246 recalc_sigpending_and_wake(t);
Linus Torvaldsae74c3b2006-08-02 20:17:49 -07001247 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 }
Oleg Nesterov80fe7282008-04-30 00:53:05 -07001249 if (action->sa.sa_handler == SIG_DFL)
1250 t->signal->flags &= ~SIGNAL_UNKILLABLE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 ret = specific_send_sig_info(sig, info, t);
1252 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1253
1254 return ret;
1255}
1256
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257/*
1258 * Nuke all other threads in the group.
1259 */
Oleg Nesterov09faef12010-05-26 14:43:11 -07001260int zap_other_threads(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261{
Oleg Nesterov09faef12010-05-26 14:43:11 -07001262 struct task_struct *t = p;
1263 int count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 p->signal->group_stop_count = 0;
1266
Oleg Nesterov09faef12010-05-26 14:43:11 -07001267 while_each_thread(p, t) {
Tejun Heo6dfca322011-06-02 11:14:00 +02001268 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
Oleg Nesterov09faef12010-05-26 14:43:11 -07001269 count++;
1270
1271 /* Don't bother with already dead threads */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272 if (t->exit_state)
1273 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 sigaddset(&t->pending.signal, SIGKILL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 signal_wake_up(t, 1);
1276 }
Oleg Nesterov09faef12010-05-26 14:43:11 -07001277
1278 return count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279}
1280
Namhyung Kimb8ed3742010-10-27 15:34:06 -07001281struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1282 unsigned long *flags)
Oleg Nesterovf63ee722006-03-28 16:11:13 -08001283{
1284 struct sighand_struct *sighand;
1285
1286 for (;;) {
Paul E. McKenneya8417962011-07-19 03:25:36 -07001287 local_irq_save(*flags);
1288 rcu_read_lock();
Oleg Nesterovf63ee722006-03-28 16:11:13 -08001289 sighand = rcu_dereference(tsk->sighand);
Paul E. McKenneya8417962011-07-19 03:25:36 -07001290 if (unlikely(sighand == NULL)) {
1291 rcu_read_unlock();
1292 local_irq_restore(*flags);
Oleg Nesterovf63ee722006-03-28 16:11:13 -08001293 break;
Paul E. McKenneya8417962011-07-19 03:25:36 -07001294 }
Oleg Nesterovf63ee722006-03-28 16:11:13 -08001295
Paul E. McKenneya8417962011-07-19 03:25:36 -07001296 spin_lock(&sighand->siglock);
1297 if (likely(sighand == tsk->sighand)) {
1298 rcu_read_unlock();
Oleg Nesterovf63ee722006-03-28 16:11:13 -08001299 break;
Paul E. McKenneya8417962011-07-19 03:25:36 -07001300 }
1301 spin_unlock(&sighand->siglock);
1302 rcu_read_unlock();
1303 local_irq_restore(*flags);
Oleg Nesterovf63ee722006-03-28 16:11:13 -08001304 }
1305
1306 return sighand;
1307}
1308
David Howellsc69e8d92008-11-14 10:39:19 +11001309/*
1310 * send signal info to all the members of a group
David Howellsc69e8d92008-11-14 10:39:19 +11001311 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1313{
David Howells694f6902010-08-04 16:59:14 +01001314 int ret;
1315
1316 rcu_read_lock();
1317 ret = check_kill_permission(sig, info, p);
1318 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
Oleg Nesterov4a30deb2009-09-23 15:57:00 -07001320 if (!ret && sig)
1321 ret = do_send_sig_info(sig, info, p, true);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322
1323 return ret;
1324}
1325
1326/*
Pavel Emelyanov146a5052008-02-08 04:19:22 -08001327 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 * control characters do (^C, ^Z etc)
David Howellsc69e8d92008-11-14 10:39:19 +11001329 * - the caller must hold at least a readlock on tasklist_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 */
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001331int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332{
1333 struct task_struct *p = NULL;
1334 int retval, success;
1335
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 success = 0;
1337 retval = -ESRCH;
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001338 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 int err = group_send_sig_info(sig, info, p);
1340 success |= !err;
1341 retval = err;
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001342 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 return success ? 0 : retval;
1344}
1345
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001346int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347{
Oleg Nesterovd36174b2008-02-08 04:19:18 -08001348 int error = -ESRCH;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 struct task_struct *p;
1350
Ingo Molnare56d0902006-01-08 01:01:37 -08001351 rcu_read_lock();
Oleg Nesterovd36174b2008-02-08 04:19:18 -08001352retry:
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001353 p = pid_task(pid, PIDTYPE_PID);
Oleg Nesterovd36174b2008-02-08 04:19:18 -08001354 if (p) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 error = group_send_sig_info(sig, info, p);
Oleg Nesterovd36174b2008-02-08 04:19:18 -08001356 if (unlikely(error == -ESRCH))
1357 /*
1358 * The task was unhashed in between, try again.
1359 * If it is dead, pid_task() will return NULL,
1360 * if we race with de_thread() it will find the
1361 * new leader.
1362 */
1363 goto retry;
1364 }
Ingo Molnare56d0902006-01-08 01:01:37 -08001365 rcu_read_unlock();
Oleg Nesterov6ca25b52008-04-30 00:52:45 -07001366
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367 return error;
1368}
1369
Randy Dunlap5aba0852011-04-04 14:59:31 -07001370int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001371{
1372 int error;
1373 rcu_read_lock();
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001374 error = kill_pid_info(sig, info, find_vpid(pid));
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001375 rcu_read_unlock();
1376 return error;
1377}
1378
Serge Hallynd178bc32011-09-26 10:45:18 -05001379static int kill_as_cred_perm(const struct cred *cred,
1380 struct task_struct *target)
1381{
1382 const struct cred *pcred = __task_cred(target);
Eric W. Biederman5af66202012-03-03 20:21:47 -08001383 if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
1384 !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid))
Serge Hallynd178bc32011-09-26 10:45:18 -05001385 return 0;
1386 return 1;
1387}
1388
Eric W. Biederman2425c082006-10-02 02:17:28 -07001389/* like kill_pid_info(), but doesn't use uid/euid of "current" */
Serge Hallynd178bc32011-09-26 10:45:18 -05001390int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
1391 const struct cred *cred, u32 secid)
Harald Welte46113832005-10-10 19:44:29 +02001392{
1393 int ret = -EINVAL;
1394 struct task_struct *p;
Thomas Gleixner14d8c9f2009-12-10 00:53:17 +00001395 unsigned long flags;
Harald Welte46113832005-10-10 19:44:29 +02001396
1397 if (!valid_signal(sig))
1398 return ret;
1399
Thomas Gleixner14d8c9f2009-12-10 00:53:17 +00001400 rcu_read_lock();
Eric W. Biederman2425c082006-10-02 02:17:28 -07001401 p = pid_task(pid, PIDTYPE_PID);
Harald Welte46113832005-10-10 19:44:29 +02001402 if (!p) {
1403 ret = -ESRCH;
1404 goto out_unlock;
1405 }
Serge Hallynd178bc32011-09-26 10:45:18 -05001406 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
Harald Welte46113832005-10-10 19:44:29 +02001407 ret = -EPERM;
1408 goto out_unlock;
1409 }
David Quigley8f95dc52006-06-30 01:55:47 -07001410 ret = security_task_kill(p, info, sig, secid);
1411 if (ret)
1412 goto out_unlock;
Thomas Gleixner14d8c9f2009-12-10 00:53:17 +00001413
1414 if (sig) {
1415 if (lock_task_sighand(p, &flags)) {
1416 ret = __send_signal(sig, info, p, 1, 0);
1417 unlock_task_sighand(p, &flags);
1418 } else
1419 ret = -ESRCH;
Harald Welte46113832005-10-10 19:44:29 +02001420 }
1421out_unlock:
Thomas Gleixner14d8c9f2009-12-10 00:53:17 +00001422 rcu_read_unlock();
Harald Welte46113832005-10-10 19:44:29 +02001423 return ret;
1424}
Serge Hallynd178bc32011-09-26 10:45:18 -05001425EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426
1427/*
1428 * kill_something_info() interprets pid in interesting ways just like kill(2).
1429 *
1430 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1431 * is probably wrong. Should make it like BSD or SYSV.
1432 */
1433
Gustavo Fernando Padovanbc64efd2008-07-25 01:47:33 -07001434static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435{
Eric W. Biederman8d42db182007-02-12 00:52:55 -08001436 int ret;
Pavel Emelyanovd5df7632008-02-08 04:19:22 -08001437
1438 if (pid > 0) {
1439 rcu_read_lock();
1440 ret = kill_pid_info(sig, info, find_vpid(pid));
1441 rcu_read_unlock();
1442 return ret;
1443 }
1444
1445 read_lock(&tasklist_lock);
1446 if (pid != -1) {
1447 ret = __kill_pgrp_info(sig, info,
1448 pid ? find_vpid(-pid) : task_pgrp(current));
1449 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450 int retval = 0, count = 0;
1451 struct task_struct * p;
1452
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 for_each_process(p) {
Sukadev Bhattiprolud25141a2008-10-29 14:01:11 -07001454 if (task_pid_vnr(p) > 1 &&
1455 !same_thread_group(p, current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456 int err = group_send_sig_info(sig, info, p);
1457 ++count;
1458 if (err != -EPERM)
1459 retval = err;
1460 }
1461 }
Eric W. Biederman8d42db182007-02-12 00:52:55 -08001462 ret = count ? retval : -ESRCH;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463 }
Pavel Emelyanovd5df7632008-02-08 04:19:22 -08001464 read_unlock(&tasklist_lock);
1465
Eric W. Biederman8d42db182007-02-12 00:52:55 -08001466 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467}
1468
1469/*
1470 * These are for backward compatibility with the rest of the kernel source.
1471 */
1472
Randy Dunlap5aba0852011-04-04 14:59:31 -07001473int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 /*
1476 * Make sure legacy kernel users don't send in bad values
1477 * (normal paths check this in check_kill_permission).
1478 */
Jesper Juhl7ed20e12005-05-01 08:59:14 -07001479 if (!valid_signal(sig))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 return -EINVAL;
1481
Oleg Nesterov4a30deb2009-09-23 15:57:00 -07001482 return do_send_sig_info(sig, info, p, false);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483}
1484
Oleg Nesterovb67a1b92005-10-30 15:03:44 -08001485#define __si_special(priv) \
1486 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1487
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488int
1489send_sig(int sig, struct task_struct *p, int priv)
1490{
Oleg Nesterovb67a1b92005-10-30 15:03:44 -08001491 return send_sig_info(sig, __si_special(priv), p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492}
1493
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494void
1495force_sig(int sig, struct task_struct *p)
1496{
Oleg Nesterovb67a1b92005-10-30 15:03:44 -08001497 force_sig_info(sig, SEND_SIG_PRIV, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498}
1499
1500/*
1501 * When things go south during signal handling, we
1502 * will force a SIGSEGV. And if the signal that caused
1503 * the problem was already a SIGSEGV, we'll want to
1504 * make sure we don't even try to deliver the signal..
1505 */
1506int
1507force_sigsegv(int sig, struct task_struct *p)
1508{
1509 if (sig == SIGSEGV) {
1510 unsigned long flags;
1511 spin_lock_irqsave(&p->sighand->siglock, flags);
1512 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1513 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1514 }
1515 force_sig(SIGSEGV, p);
1516 return 0;
1517}
1518
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001519int kill_pgrp(struct pid *pid, int sig, int priv)
1520{
Pavel Emelyanov146a5052008-02-08 04:19:22 -08001521 int ret;
1522
1523 read_lock(&tasklist_lock);
1524 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1525 read_unlock(&tasklist_lock);
1526
1527 return ret;
Eric W. Biedermanc4b92fc2006-10-02 02:17:10 -07001528}
1529EXPORT_SYMBOL(kill_pgrp);
1530
1531int kill_pid(struct pid *pid, int sig, int priv)
1532{
1533 return kill_pid_info(sig, __si_special(priv), pid);
1534}
1535EXPORT_SYMBOL(kill_pid);
1536
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537/*
1538 * These functions support sending signals using preallocated sigqueue
1539 * structures. This is needed "because realtime applications cannot
1540 * afford to lose notifications of asynchronous events, like timer
Randy Dunlap5aba0852011-04-04 14:59:31 -07001541 * expirations or I/O completions". In the case of POSIX Timers
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542 * we allocate the sigqueue structure from the timer_create. If this
1543 * allocation fails we are able to report the failure to the application
1544 * with an EAGAIN error.
1545 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546struct sigqueue *sigqueue_alloc(void)
1547{
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +09001548 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +09001550 if (q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 q->flags |= SIGQUEUE_PREALLOC;
Naohiro Ooiwaf84d49b2009-11-09 00:46:42 +09001552
1553 return q;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554}
1555
1556void sigqueue_free(struct sigqueue *q)
1557{
1558 unsigned long flags;
Oleg Nesterov60187d22007-08-30 23:56:35 -07001559 spinlock_t *lock = &current->sighand->siglock;
1560
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1562 /*
Oleg Nesterovc8e85b4f2008-05-26 20:55:42 +04001563 * We must hold ->siglock while testing q->list
1564 * to serialize with collect_signal() or with
Oleg Nesterovda7978b2008-05-23 13:04:41 -07001565 * __exit_signal()->flush_sigqueue().
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 */
Oleg Nesterov60187d22007-08-30 23:56:35 -07001567 spin_lock_irqsave(lock, flags);
Oleg Nesterovc8e85b4f2008-05-26 20:55:42 +04001568 q->flags &= ~SIGQUEUE_PREALLOC;
1569 /*
1570 * If it is queued it will be freed when dequeued,
1571 * like the "regular" sigqueue.
1572 */
Oleg Nesterov60187d22007-08-30 23:56:35 -07001573 if (!list_empty(&q->list))
Oleg Nesterovc8e85b4f2008-05-26 20:55:42 +04001574 q = NULL;
Oleg Nesterov60187d22007-08-30 23:56:35 -07001575 spin_unlock_irqrestore(lock, flags);
1576
Oleg Nesterovc8e85b4f2008-05-26 20:55:42 +04001577 if (q)
1578 __sigqueue_free(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579}
1580
Oleg Nesterovac5c2152008-04-30 00:52:57 -07001581int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001582{
Oleg Nesterove62e6652008-04-30 00:52:56 -07001583 int sig = q->info.si_signo;
Oleg Nesterov2ca35152008-04-30 00:52:54 -07001584 struct sigpending *pending;
Oleg Nesterove62e6652008-04-30 00:52:56 -07001585 unsigned long flags;
Oleg Nesterov163566f2011-11-22 21:37:41 +01001586 int ret, result;
Oleg Nesterov2ca35152008-04-30 00:52:54 -07001587
Pavel Emelyanov4cd4b6d2008-04-30 00:52:55 -07001588 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
Oleg Nesterove62e6652008-04-30 00:52:56 -07001589
1590 ret = -1;
1591 if (!likely(lock_task_sighand(t, &flags)))
1592 goto ret;
1593
Oleg Nesterov7e695a52008-04-30 00:52:59 -07001594 ret = 1; /* the signal is ignored */
Oleg Nesterov163566f2011-11-22 21:37:41 +01001595 result = TRACE_SIGNAL_IGNORED;
Oleg Nesterovdef8cf72012-03-23 15:02:45 -07001596 if (!prepare_signal(sig, t, false))
Oleg Nesterove62e6652008-04-30 00:52:56 -07001597 goto out;
1598
1599 ret = 0;
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001600 if (unlikely(!list_empty(&q->list))) {
1601 /*
1602 * If an SI_TIMER entry is already queue just increment
1603 * the overrun count.
1604 */
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001605 BUG_ON(q->info.si_code != SI_TIMER);
1606 q->info.si_overrun++;
Oleg Nesterov163566f2011-11-22 21:37:41 +01001607 result = TRACE_SIGNAL_ALREADY_PENDING;
Oleg Nesterove62e6652008-04-30 00:52:56 -07001608 goto out;
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001609 }
Oleg Nesterovba661292008-07-23 20:52:05 +04001610 q->info.si_overrun = 0;
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001611
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001612 signalfd_notify(t, sig);
Oleg Nesterov2ca35152008-04-30 00:52:54 -07001613 pending = group ? &t->signal->shared_pending : &t->pending;
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001614 list_add_tail(&q->list, &pending->list);
1615 sigaddset(&pending->signal, sig);
Pavel Emelyanov4cd4b6d2008-04-30 00:52:55 -07001616 complete_signal(sig, t, group);
Oleg Nesterov163566f2011-11-22 21:37:41 +01001617 result = TRACE_SIGNAL_DELIVERED;
Oleg Nesterove62e6652008-04-30 00:52:56 -07001618out:
Oleg Nesterov163566f2011-11-22 21:37:41 +01001619 trace_signal_generate(sig, &q->info, t, group, result);
Oleg Nesterove62e6652008-04-30 00:52:56 -07001620 unlock_task_sighand(t, &flags);
1621ret:
1622 return ret;
Pavel Emelyanov9e3bd6c2008-04-30 00:52:41 -07001623}
1624
Linus Torvalds1da177e2005-04-16 15:20:36 -07001625/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626 * Let a parent know about the death of a child.
1627 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
Roland McGrath2b2a1ff2008-07-25 19:45:54 -07001628 *
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +02001629 * Returns true if our parent ignored us and so we've switched to
1630 * self-reaping.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 */
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +02001632bool do_notify_parent(struct task_struct *tsk, int sig)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633{
1634 struct siginfo info;
1635 unsigned long flags;
1636 struct sighand_struct *psig;
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +02001637 bool autoreap = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638
1639 BUG_ON(sig == -1);
1640
1641 /* do_notify_parent_cldstop should have been called instead. */
Matthew Wilcoxe1abb392007-12-06 11:07:35 -05001642 BUG_ON(task_is_stopped_or_traced(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001643
Tejun Heod21142e2011-06-17 16:50:34 +02001644 BUG_ON(!tsk->ptrace &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1646
Oleg Nesterovb6e238d2012-03-19 17:03:41 +01001647 if (sig != SIGCHLD) {
1648 /*
1649 * This is only possible if parent == real_parent.
1650 * Check if it has changed security domain.
1651 */
1652 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1653 sig = SIGCHLD;
1654 }
1655
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656 info.si_signo = sig;
1657 info.si_errno = 0;
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001658 /*
Eric W. Biederman32084502012-05-31 16:26:39 -07001659 * We are under tasklist_lock here so our parent is tied to
1660 * us and cannot change.
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001661 *
Eric W. Biederman32084502012-05-31 16:26:39 -07001662 * task_active_pid_ns will always return the same pid namespace
1663 * until a task passes through release_task.
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001664 *
1665 * write_lock() currently calls preempt_disable() which is the
1666 * same as rcu_read_lock(), but according to Oleg, this is not
1667 * correct to rely on this
1668 */
1669 rcu_read_lock();
Eric W. Biederman32084502012-05-31 16:26:39 -07001670 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
Eric W. Biederman54ba47e2012-03-13 16:04:35 -07001671 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1672 task_uid(tsk));
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001673 rcu_read_unlock();
1674
Martin Schwidefsky64861632011-12-15 14:56:09 +01001675 info.si_utime = cputime_to_clock_t(tsk->utime + tsk->signal->utime);
1676 info.si_stime = cputime_to_clock_t(tsk->stime + tsk->signal->stime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677
1678 info.si_status = tsk->exit_code & 0x7f;
1679 if (tsk->exit_code & 0x80)
1680 info.si_code = CLD_DUMPED;
1681 else if (tsk->exit_code & 0x7f)
1682 info.si_code = CLD_KILLED;
1683 else {
1684 info.si_code = CLD_EXITED;
1685 info.si_status = tsk->exit_code >> 8;
1686 }
1687
1688 psig = tsk->parent->sighand;
1689 spin_lock_irqsave(&psig->siglock, flags);
Tejun Heod21142e2011-06-17 16:50:34 +02001690 if (!tsk->ptrace && sig == SIGCHLD &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1692 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1693 /*
1694 * We are exiting and our parent doesn't care. POSIX.1
1695 * defines special semantics for setting SIGCHLD to SIG_IGN
1696 * or setting the SA_NOCLDWAIT flag: we should be reaped
1697 * automatically and not left for our parent's wait4 call.
1698 * Rather than having the parent do it as a magic kind of
1699 * signal handler, we just set this to tell do_exit that we
1700 * can be cleaned up without becoming a zombie. Note that
1701 * we still call __wake_up_parent in this case, because a
1702 * blocked sys_wait4 might now return -ECHILD.
1703 *
1704 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1705 * is implementation-defined: we do (if you don't want
1706 * it, just use SIG_IGN instead).
1707 */
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +02001708 autoreap = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +02001710 sig = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001711 }
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +02001712 if (valid_signal(sig) && sig)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713 __group_send_sig_info(sig, &info, tsk->parent);
1714 __wake_up_parent(tsk, tsk->parent);
1715 spin_unlock_irqrestore(&psig->siglock, flags);
Roland McGrath2b2a1ff2008-07-25 19:45:54 -07001716
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +02001717 return autoreap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718}
1719
Tejun Heo75b95952011-03-23 10:37:01 +01001720/**
1721 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1722 * @tsk: task reporting the state change
1723 * @for_ptracer: the notification is for ptracer
1724 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1725 *
1726 * Notify @tsk's parent that the stopped/continued state has changed. If
1727 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1728 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1729 *
1730 * CONTEXT:
1731 * Must be called with tasklist_lock at least read locked.
1732 */
1733static void do_notify_parent_cldstop(struct task_struct *tsk,
1734 bool for_ptracer, int why)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735{
1736 struct siginfo info;
1737 unsigned long flags;
Oleg Nesterovbc505a42005-09-06 15:17:32 -07001738 struct task_struct *parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739 struct sighand_struct *sighand;
1740
Tejun Heo75b95952011-03-23 10:37:01 +01001741 if (for_ptracer) {
Oleg Nesterovbc505a42005-09-06 15:17:32 -07001742 parent = tsk->parent;
Tejun Heo75b95952011-03-23 10:37:01 +01001743 } else {
Oleg Nesterovbc505a42005-09-06 15:17:32 -07001744 tsk = tsk->group_leader;
1745 parent = tsk->real_parent;
1746 }
1747
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748 info.si_signo = SIGCHLD;
1749 info.si_errno = 0;
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001750 /*
Randy Dunlap5aba0852011-04-04 14:59:31 -07001751 * see comment in do_notify_parent() about the following 4 lines
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001752 */
1753 rcu_read_lock();
Oleg Nesterovd9265662009-06-17 16:27:35 -07001754 info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
Eric W. Biederman54ba47e2012-03-13 16:04:35 -07001755 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001756 rcu_read_unlock();
1757
Michael Kerriskd8878ba2008-07-25 01:47:32 -07001758 info.si_utime = cputime_to_clock_t(tsk->utime);
1759 info.si_stime = cputime_to_clock_t(tsk->stime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760
1761 info.si_code = why;
1762 switch (why) {
1763 case CLD_CONTINUED:
1764 info.si_status = SIGCONT;
1765 break;
1766 case CLD_STOPPED:
1767 info.si_status = tsk->signal->group_exit_code & 0x7f;
1768 break;
1769 case CLD_TRAPPED:
1770 info.si_status = tsk->exit_code & 0x7f;
1771 break;
1772 default:
1773 BUG();
1774 }
1775
1776 sighand = parent->sighand;
1777 spin_lock_irqsave(&sighand->siglock, flags);
1778 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1779 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1780 __group_send_sig_info(SIGCHLD, &info, parent);
1781 /*
1782 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1783 */
1784 __wake_up_parent(tsk, parent);
1785 spin_unlock_irqrestore(&sighand->siglock, flags);
1786}
1787
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001788static inline int may_ptrace_stop(void)
1789{
Tejun Heod21142e2011-06-17 16:50:34 +02001790 if (!likely(current->ptrace))
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001791 return 0;
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001792 /*
1793 * Are we in the middle of do_coredump?
1794 * If so and our tracer is also part of the coredump stopping
1795 * is a deadlock situation, and pointless because our tracer
1796 * is dead so don't allow us to stop.
1797 * If SIGKILL was already sent before the caller unlocked
Oleg Nesterov999d9fc2008-07-25 01:47:41 -07001798 * ->siglock we must see ->core_state != NULL. Otherwise it
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001799 * is safe to enter schedule().
1800 */
Oleg Nesterov999d9fc2008-07-25 01:47:41 -07001801 if (unlikely(current->mm->core_state) &&
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001802 unlikely(current->mm == current->parent->mm))
1803 return 0;
1804
1805 return 1;
1806}
1807
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808/*
Randy Dunlap5aba0852011-04-04 14:59:31 -07001809 * Return non-zero if there is a SIGKILL that should be waking us up.
Roland McGrath1a669c22008-02-06 01:37:37 -08001810 * Called with the siglock held.
1811 */
1812static int sigkill_pending(struct task_struct *tsk)
1813{
Oleg Nesterov3d749b92008-07-25 01:47:37 -07001814 return sigismember(&tsk->pending.signal, SIGKILL) ||
1815 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
Roland McGrath1a669c22008-02-06 01:37:37 -08001816}
1817
1818/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819 * This must be called with current->sighand->siglock held.
1820 *
1821 * This should be the path for all ptrace stops.
1822 * We always set current->last_siginfo while stopped here.
1823 * That makes it a way to test a stopped process for
1824 * being ptrace-stopped vs being job-control-stopped.
1825 *
Oleg Nesterov20686a32008-02-08 04:19:03 -08001826 * If we actually decide not to stop at all because the tracer
1827 * is gone, we keep current->exit_code unless clear_code.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001828 */
Tejun Heofe1bc6a2011-03-23 10:37:00 +01001829static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
Namhyung Kimb8401152010-10-27 15:34:07 -07001830 __releases(&current->sighand->siglock)
1831 __acquires(&current->sighand->siglock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832{
Tejun Heoceb6bd62011-03-23 10:37:01 +01001833 bool gstop_done = false;
1834
Roland McGrath1a669c22008-02-06 01:37:37 -08001835 if (arch_ptrace_stop_needed(exit_code, info)) {
1836 /*
1837 * The arch code has something special to do before a
1838 * ptrace stop. This is allowed to block, e.g. for faults
1839 * on user stack pages. We can't keep the siglock while
1840 * calling arch_ptrace_stop, so we must release it now.
1841 * To preserve proper semantics, we must do this before
1842 * any signal bookkeeping like checking group_stop_count.
1843 * Meanwhile, a SIGKILL could come in before we retake the
1844 * siglock. That must prevent us from sleeping in TASK_TRACED.
1845 * So after regaining the lock, we must check for SIGKILL.
1846 */
1847 spin_unlock_irq(&current->sighand->siglock);
1848 arch_ptrace_stop(exit_code, info);
1849 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterov3d749b92008-07-25 01:47:37 -07001850 if (sigkill_pending(current))
1851 return;
Roland McGrath1a669c22008-02-06 01:37:37 -08001852 }
1853
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 /*
Tejun Heo81be24b2011-06-02 11:13:59 +02001855 * We're committing to trapping. TRACED should be visible before
1856 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1857 * Also, transition to TRACED and updates to ->jobctl should be
1858 * atomic with respect to siglock and should be done after the arch
1859 * hook as siglock is released and regrabbed across it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001860 */
Tejun Heo81be24b2011-06-02 11:13:59 +02001861 set_current_state(TASK_TRACED);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862
1863 current->last_siginfo = info;
1864 current->exit_code = exit_code;
1865
Tejun Heod79fdd62011-03-23 10:37:00 +01001866 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 * If @why is CLD_STOPPED, we're trapping to participate in a group
1868 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
Tejun Heo73ddff22011-06-14 11:20:14 +02001869 * across siglock relocks since INTERRUPT was scheduled, PENDING
1870 * could be clear now. We act as if SIGCONT is received after
1871 * TASK_TRACED is entered - ignore it.
Tejun Heod79fdd62011-03-23 10:37:00 +01001872 */
Tejun Heoa8f072c2011-06-02 11:13:59 +02001873 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001874 gstop_done = task_participate_group_stop(current);
Tejun Heod79fdd62011-03-23 10:37:00 +01001875
Tejun Heofb1d9102011-06-14 11:20:17 +02001876 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
Tejun Heo73ddff22011-06-14 11:20:14 +02001877 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
Tejun Heofb1d9102011-06-14 11:20:17 +02001878 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
1879 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
Tejun Heo73ddff22011-06-14 11:20:14 +02001880
Tejun Heo81be24b2011-06-02 11:13:59 +02001881 /* entering a trap, clear TRAPPING */
Tejun Heoa8f072c2011-06-02 11:13:59 +02001882 task_clear_jobctl_trapping(current);
Tejun Heod79fdd62011-03-23 10:37:00 +01001883
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884 spin_unlock_irq(&current->sighand->siglock);
1885 read_lock(&tasklist_lock);
Oleg Nesterov3d749b92008-07-25 01:47:37 -07001886 if (may_ptrace_stop()) {
Tejun Heoceb6bd62011-03-23 10:37:01 +01001887 /*
1888 * Notify parents of the stop.
1889 *
1890 * While ptraced, there are two parents - the ptracer and
1891 * the real_parent of the group_leader. The ptracer should
1892 * know about every stop while the real parent is only
1893 * interested in the completion of group stop. The states
1894 * for the two don't interact with each other. Notify
1895 * separately unless they're gonna be duplicates.
1896 */
1897 do_notify_parent_cldstop(current, true, why);
Oleg Nesterovbb3696d2011-06-24 17:34:23 +02001898 if (gstop_done && ptrace_reparented(current))
Tejun Heoceb6bd62011-03-23 10:37:01 +01001899 do_notify_parent_cldstop(current, false, why);
1900
Miklos Szeredi53da1d92009-03-23 16:07:24 +01001901 /*
1902 * Don't want to allow preemption here, because
1903 * sys_ptrace() needs this task to be inactive.
1904 *
1905 * XXX: implement read_unlock_no_resched().
1906 */
1907 preempt_disable();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 read_unlock(&tasklist_lock);
Miklos Szeredi53da1d92009-03-23 16:07:24 +01001909 preempt_enable_no_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 schedule();
1911 } else {
1912 /*
1913 * By the time we got the lock, our tracer went away.
Oleg Nesterov6405f7f2008-02-08 04:19:00 -08001914 * Don't drop the lock yet, another tracer may come.
Tejun Heoceb6bd62011-03-23 10:37:01 +01001915 *
1916 * If @gstop_done, the ptracer went away between group stop
1917 * completion and here. During detach, it would have set
Tejun Heoa8f072c2011-06-02 11:13:59 +02001918 * JOBCTL_STOP_PENDING on us and we'll re-enter
1919 * TASK_STOPPED in do_signal_stop() on return, so notifying
1920 * the real parent of the group stop completion is enough.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 */
Tejun Heoceb6bd62011-03-23 10:37:01 +01001922 if (gstop_done)
1923 do_notify_parent_cldstop(current, false, why);
1924
Oleg Nesterov6405f7f2008-02-08 04:19:00 -08001925 __set_current_state(TASK_RUNNING);
Oleg Nesterov20686a32008-02-08 04:19:03 -08001926 if (clear_code)
1927 current->exit_code = 0;
Oleg Nesterov6405f7f2008-02-08 04:19:00 -08001928 read_unlock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001929 }
1930
1931 /*
Roland McGrath13b1c3d2008-03-03 20:22:05 -08001932 * While in TASK_TRACED, we were considered "frozen enough".
1933 * Now that we woke up, it's crucial if we're supposed to be
1934 * frozen that we freeze now before running anything substantial.
1935 */
1936 try_to_freeze();
1937
1938 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 * We are back. Now reacquire the siglock before touching
1940 * last_siginfo, so that we are sure to have synchronized with
1941 * any signal-sending on another CPU that wants to examine it.
1942 */
1943 spin_lock_irq(&current->sighand->siglock);
1944 current->last_siginfo = NULL;
1945
Tejun Heo544b2c92011-06-14 11:20:18 +02001946 /* LISTENING can be set only during STOP traps, clear it */
1947 current->jobctl &= ~JOBCTL_LISTENING;
1948
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949 /*
1950 * Queued signals ignored us while we were stopped for tracing.
1951 * So check for any that we should take before resuming user mode.
Roland McGrathb74d0de2007-06-06 03:59:00 -07001952 * This sets TIF_SIGPENDING, but never clears it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953 */
Roland McGrathb74d0de2007-06-06 03:59:00 -07001954 recalc_sigpending_tsk(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955}
1956
Tejun Heo3544d722011-06-14 11:20:15 +02001957static void ptrace_do_notify(int signr, int exit_code, int why)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958{
1959 siginfo_t info;
1960
Linus Torvalds1da177e2005-04-16 15:20:36 -07001961 memset(&info, 0, sizeof info);
Tejun Heo3544d722011-06-14 11:20:15 +02001962 info.si_signo = signr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001963 info.si_code = exit_code;
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001964 info.si_pid = task_pid_vnr(current);
Eric W. Biederman078de5f2012-02-08 07:00:08 -08001965 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
Linus Torvalds1da177e2005-04-16 15:20:36 -07001966
1967 /* Let the debugger run. */
Tejun Heo3544d722011-06-14 11:20:15 +02001968 ptrace_stop(exit_code, why, 1, &info);
1969}
1970
1971void ptrace_notify(int exit_code)
1972{
1973 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1974
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 spin_lock_irq(&current->sighand->siglock);
Tejun Heo3544d722011-06-14 11:20:15 +02001976 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 spin_unlock_irq(&current->sighand->siglock);
1978}
1979
Tejun Heo73ddff22011-06-14 11:20:14 +02001980/**
1981 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
1982 * @signr: signr causing group stop if initiating
1983 *
1984 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
1985 * and participate in it. If already set, participate in the existing
1986 * group stop. If participated in a group stop (and thus slept), %true is
1987 * returned with siglock released.
1988 *
1989 * If ptraced, this function doesn't handle stop itself. Instead,
1990 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
1991 * untouched. The caller must ensure that INTERRUPT trap handling takes
1992 * places afterwards.
1993 *
1994 * CONTEXT:
1995 * Must be called with @current->sighand->siglock held, which is released
1996 * on %true return.
1997 *
1998 * RETURNS:
1999 * %false if group stop is already cancelled or ptrace trap is scheduled.
2000 * %true if participated in group stop.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001 */
Tejun Heo73ddff22011-06-14 11:20:14 +02002002static bool do_signal_stop(int signr)
2003 __releases(&current->sighand->siglock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002004{
2005 struct signal_struct *sig = current->signal;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002006
Tejun Heoa8f072c2011-06-02 11:13:59 +02002007 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2008 unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
Oleg Nesterovf558b7e2008-02-04 22:27:24 -08002009 struct task_struct *t;
2010
Tejun Heoa8f072c2011-06-02 11:13:59 +02002011 /* signr will be recorded in task->jobctl for retries */
2012 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
Tejun Heod79fdd62011-03-23 10:37:00 +01002013
Tejun Heoa8f072c2011-06-02 11:13:59 +02002014 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
Oleg Nesterov573cf9a2008-04-30 00:52:36 -07002015 unlikely(signal_group_exit(sig)))
Tejun Heo73ddff22011-06-14 11:20:14 +02002016 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002017 /*
Tejun Heo408a37d2011-03-23 10:37:01 +01002018 * There is no group stop already in progress. We must
2019 * initiate one now.
2020 *
2021 * While ptraced, a task may be resumed while group stop is
2022 * still in effect and then receive a stop signal and
2023 * initiate another group stop. This deviates from the
2024 * usual behavior as two consecutive stop signals can't
Oleg Nesterov780006eac2011-04-01 20:12:16 +02002025 * cause two group stops when !ptraced. That is why we
2026 * also check !task_is_stopped(t) below.
Tejun Heo408a37d2011-03-23 10:37:01 +01002027 *
2028 * The condition can be distinguished by testing whether
2029 * SIGNAL_STOP_STOPPED is already set. Don't generate
2030 * group_exit_code in such case.
2031 *
2032 * This is not necessary for SIGNAL_STOP_CONTINUED because
2033 * an intervening stop signal is required to cause two
2034 * continued events regardless of ptrace.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002035 */
Tejun Heo408a37d2011-03-23 10:37:01 +01002036 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2037 sig->group_exit_code = signr;
Oleg Nesterova122b342006-03-28 16:11:22 -08002038
Tejun Heo7dd3db52011-06-02 11:14:00 +02002039 sig->group_stop_count = 0;
2040
2041 if (task_set_jobctl_pending(current, signr | gstop))
2042 sig->group_stop_count++;
2043
Tejun Heod79fdd62011-03-23 10:37:00 +01002044 for (t = next_thread(current); t != current;
2045 t = next_thread(t)) {
Oleg Nesterova122b342006-03-28 16:11:22 -08002046 /*
2047 * Setting state to TASK_STOPPED for a group
2048 * stop is always done with the siglock held,
2049 * so this check has no races.
2050 */
Tejun Heo7dd3db52011-06-02 11:14:00 +02002051 if (!task_is_stopped(t) &&
2052 task_set_jobctl_pending(t, signr | gstop)) {
Roland McGrathae6d2ed2009-09-23 15:56:53 -07002053 sig->group_stop_count++;
Tejun Heofb1d9102011-06-14 11:20:17 +02002054 if (likely(!(t->ptrace & PT_SEIZED)))
2055 signal_wake_up(t, 0);
2056 else
2057 ptrace_trap_notify(t);
Oleg Nesterova122b342006-03-28 16:11:22 -08002058 }
Tejun Heod79fdd62011-03-23 10:37:00 +01002059 }
Roland McGrathae6d2ed2009-09-23 15:56:53 -07002060 }
Tejun Heo73ddff22011-06-14 11:20:14 +02002061
Tejun Heod21142e2011-06-17 16:50:34 +02002062 if (likely(!current->ptrace)) {
Tejun Heo5224fa32011-03-23 10:37:00 +01002063 int notify = 0;
2064
2065 /*
2066 * If there are no other threads in the group, or if there
2067 * is a group stop in progress and we are the last to stop,
2068 * report to the parent.
2069 */
2070 if (task_participate_group_stop(current))
2071 notify = CLD_STOPPED;
2072
Roland McGrathae6d2ed2009-09-23 15:56:53 -07002073 __set_current_state(TASK_STOPPED);
Tejun Heo5224fa32011-03-23 10:37:00 +01002074 spin_unlock_irq(&current->sighand->siglock);
2075
Tejun Heo62bcf9d2011-03-23 10:37:01 +01002076 /*
2077 * Notify the parent of the group stop completion. Because
2078 * we're not holding either the siglock or tasklist_lock
2079 * here, ptracer may attach inbetween; however, this is for
2080 * group stop and should always be delivered to the real
2081 * parent of the group leader. The new ptracer will get
2082 * its notification when this task transitions into
2083 * TASK_TRACED.
2084 */
Tejun Heo5224fa32011-03-23 10:37:00 +01002085 if (notify) {
2086 read_lock(&tasklist_lock);
Tejun Heo62bcf9d2011-03-23 10:37:01 +01002087 do_notify_parent_cldstop(current, false, notify);
Tejun Heo5224fa32011-03-23 10:37:00 +01002088 read_unlock(&tasklist_lock);
2089 }
2090
2091 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2092 schedule();
Tejun Heo73ddff22011-06-14 11:20:14 +02002093 return true;
Tejun Heod79fdd62011-03-23 10:37:00 +01002094 } else {
Tejun Heo73ddff22011-06-14 11:20:14 +02002095 /*
2096 * While ptraced, group stop is handled by STOP trap.
2097 * Schedule it and let the caller deal with it.
2098 */
2099 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2100 return false;
Roland McGrathae6d2ed2009-09-23 15:56:53 -07002101 }
Tejun Heo73ddff22011-06-14 11:20:14 +02002102}
Tejun Heod79fdd62011-03-23 10:37:00 +01002103
Tejun Heo73ddff22011-06-14 11:20:14 +02002104/**
2105 * do_jobctl_trap - take care of ptrace jobctl traps
2106 *
Tejun Heo3544d722011-06-14 11:20:15 +02002107 * When PT_SEIZED, it's used for both group stop and explicit
2108 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2109 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2110 * the stop signal; otherwise, %SIGTRAP.
2111 *
2112 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2113 * number as exit_code and no siginfo.
Tejun Heo73ddff22011-06-14 11:20:14 +02002114 *
2115 * CONTEXT:
2116 * Must be called with @current->sighand->siglock held, which may be
2117 * released and re-acquired before returning with intervening sleep.
2118 */
2119static void do_jobctl_trap(void)
2120{
Tejun Heo3544d722011-06-14 11:20:15 +02002121 struct signal_struct *signal = current->signal;
Tejun Heo73ddff22011-06-14 11:20:14 +02002122 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
Tejun Heod79fdd62011-03-23 10:37:00 +01002123
Tejun Heo3544d722011-06-14 11:20:15 +02002124 if (current->ptrace & PT_SEIZED) {
2125 if (!signal->group_stop_count &&
2126 !(signal->flags & SIGNAL_STOP_STOPPED))
2127 signr = SIGTRAP;
2128 WARN_ON_ONCE(!signr);
2129 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2130 CLD_STOPPED);
2131 } else {
2132 WARN_ON_ONCE(!signr);
2133 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
Roland McGrathae6d2ed2009-09-23 15:56:53 -07002134 current->exit_code = 0;
2135 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002136}
2137
Roland McGrath18c98b62008-04-17 18:44:38 -07002138static int ptrace_signal(int signr, siginfo_t *info,
2139 struct pt_regs *regs, void *cookie)
2140{
Roland McGrath18c98b62008-04-17 18:44:38 -07002141 ptrace_signal_deliver(regs, cookie);
Oleg Nesterov8a352412011-07-21 17:06:53 +02002142 /*
2143 * We do not check sig_kernel_stop(signr) but set this marker
2144 * unconditionally because we do not know whether debugger will
2145 * change signr. This flag has no meaning unless we are going
2146 * to stop after return from ptrace_stop(). In this case it will
2147 * be checked in do_signal_stop(), we should only stop if it was
2148 * not cleared by SIGCONT while we were sleeping. See also the
2149 * comment in dequeue_signal().
2150 */
2151 current->jobctl |= JOBCTL_STOP_DEQUEUED;
Tejun Heofe1bc6a2011-03-23 10:37:00 +01002152 ptrace_stop(signr, CLD_TRAPPED, 0, info);
Roland McGrath18c98b62008-04-17 18:44:38 -07002153
2154 /* We're back. Did the debugger cancel the sig? */
2155 signr = current->exit_code;
2156 if (signr == 0)
2157 return signr;
2158
2159 current->exit_code = 0;
2160
Randy Dunlap5aba0852011-04-04 14:59:31 -07002161 /*
2162 * Update the siginfo structure if the signal has
2163 * changed. If the debugger wanted something
2164 * specific in the siginfo structure then it should
2165 * have updated *info via PTRACE_SETSIGINFO.
2166 */
Roland McGrath18c98b62008-04-17 18:44:38 -07002167 if (signr != info->si_signo) {
2168 info->si_signo = signr;
2169 info->si_errno = 0;
2170 info->si_code = SI_USER;
Serge E. Hallyn6b550f92012-01-10 15:11:37 -08002171 rcu_read_lock();
Roland McGrath18c98b62008-04-17 18:44:38 -07002172 info->si_pid = task_pid_vnr(current->parent);
Eric W. Biederman54ba47e2012-03-13 16:04:35 -07002173 info->si_uid = from_kuid_munged(current_user_ns(),
2174 task_uid(current->parent));
Serge E. Hallyn6b550f92012-01-10 15:11:37 -08002175 rcu_read_unlock();
Roland McGrath18c98b62008-04-17 18:44:38 -07002176 }
2177
2178 /* If the (new) signal is now blocked, requeue it. */
2179 if (sigismember(&current->blocked, signr)) {
2180 specific_send_sig_info(signr, info, current);
2181 signr = 0;
2182 }
2183
2184 return signr;
2185}
2186
Linus Torvalds1da177e2005-04-16 15:20:36 -07002187int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
2188 struct pt_regs *regs, void *cookie)
2189{
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002190 struct sighand_struct *sighand = current->sighand;
2191 struct signal_struct *signal = current->signal;
2192 int signr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002193
Srikar Dronamraju0326f5a2012-03-13 23:30:11 +05302194 if (unlikely(uprobe_deny_signal()))
2195 return 0;
2196
Roland McGrath13b1c3d2008-03-03 20:22:05 -08002197relock:
2198 /*
2199 * We'll jump back here after any time we were stopped in TASK_STOPPED.
2200 * While in TASK_STOPPED, we were considered "frozen enough".
2201 * Now that we woke up, it's crucial if we're supposed to be
2202 * frozen that we freeze now before running anything substantial.
2203 */
Rafael J. Wysockifc558a72006-03-23 03:00:05 -08002204 try_to_freeze();
2205
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002206 spin_lock_irq(&sighand->siglock);
Oleg Nesterov021e1ae2008-04-30 00:53:00 -07002207 /*
2208 * Every stopped thread goes here after wakeup. Check to see if
2209 * we should notify the parent, prepare_signal(SIGCONT) encodes
2210 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2211 */
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002212 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
Tejun Heoc672af32011-03-23 10:36:59 +01002213 int why;
2214
2215 if (signal->flags & SIGNAL_CLD_CONTINUED)
2216 why = CLD_CONTINUED;
2217 else
2218 why = CLD_STOPPED;
2219
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002220 signal->flags &= ~SIGNAL_CLD_MASK;
Roland McGrathae6d2ed2009-09-23 15:56:53 -07002221
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002222 spin_unlock_irq(&sighand->siglock);
Oleg Nesterove4420552008-04-30 00:52:44 -07002223
Tejun Heoceb6bd62011-03-23 10:37:01 +01002224 /*
2225 * Notify the parent that we're continuing. This event is
2226 * always per-process and doesn't make whole lot of sense
2227 * for ptracers, who shouldn't consume the state via
2228 * wait(2) either, but, for backward compatibility, notify
2229 * the ptracer of the group leader too unless it's gonna be
2230 * a duplicate.
2231 */
Tejun Heoedf2ed12011-03-23 10:37:00 +01002232 read_lock(&tasklist_lock);
Tejun Heoceb6bd62011-03-23 10:37:01 +01002233 do_notify_parent_cldstop(current, false, why);
2234
Oleg Nesterovbb3696d2011-06-24 17:34:23 +02002235 if (ptrace_reparented(current->group_leader))
2236 do_notify_parent_cldstop(current->group_leader,
2237 true, why);
Tejun Heoedf2ed12011-03-23 10:37:00 +01002238 read_unlock(&tasklist_lock);
Tejun Heoceb6bd62011-03-23 10:37:01 +01002239
Oleg Nesterove4420552008-04-30 00:52:44 -07002240 goto relock;
2241 }
2242
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243 for (;;) {
2244 struct k_sigaction *ka;
Tejun Heodd1d6772011-06-02 11:14:00 +02002245
2246 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2247 do_signal_stop(0))
Roland McGrath7bcf6a22008-07-25 19:45:53 -07002248 goto relock;
Oleg Nesterov1be53962009-12-15 16:47:26 -08002249
Tejun Heo73ddff22011-06-14 11:20:14 +02002250 if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
2251 do_jobctl_trap();
2252 spin_unlock_irq(&sighand->siglock);
2253 goto relock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002254 }
2255
Tejun Heodd1d6772011-06-02 11:14:00 +02002256 signr = dequeue_signal(current, &current->blocked, info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257
Tejun Heodd1d6772011-06-02 11:14:00 +02002258 if (!signr)
2259 break; /* will return 0 */
2260
Oleg Nesterov8a352412011-07-21 17:06:53 +02002261 if (unlikely(current->ptrace) && signr != SIGKILL) {
Tejun Heodd1d6772011-06-02 11:14:00 +02002262 signr = ptrace_signal(signr, info,
2263 regs, cookie);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002264 if (!signr)
Tejun Heodd1d6772011-06-02 11:14:00 +02002265 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002266 }
2267
Tejun Heodd1d6772011-06-02 11:14:00 +02002268 ka = &sighand->action[signr-1];
2269
Masami Hiramatsuf9d42572009-11-24 16:56:51 -05002270 /* Trace actually delivered signals. */
2271 trace_signal_deliver(signr, info, ka);
2272
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2274 continue;
2275 if (ka->sa.sa_handler != SIG_DFL) {
2276 /* Run the handler. */
2277 *return_ka = *ka;
2278
2279 if (ka->sa.sa_flags & SA_ONESHOT)
2280 ka->sa.sa_handler = SIG_DFL;
2281
2282 break; /* will return non-zero "signr" value */
2283 }
2284
2285 /*
2286 * Now we are doing the default action for this signal.
2287 */
2288 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2289 continue;
2290
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -08002291 /*
Sukadev Bhattiprolu0fbc26a2007-10-18 23:40:13 -07002292 * Global init gets no signals it doesn't want.
Sukadev Bhattiprolub3bfa0c2009-04-02 16:58:08 -07002293 * Container-init gets no signals it doesn't want from same
2294 * container.
2295 *
2296 * Note that if global/container-init sees a sig_kernel_only()
2297 * signal here, the signal must have been generated internally
2298 * or must have come from an ancestor namespace. In either
2299 * case, the signal cannot be dropped.
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -08002300 */
Oleg Nesterovfae5fa42008-04-30 00:53:03 -07002301 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
Sukadev Bhattiprolub3bfa0c2009-04-02 16:58:08 -07002302 !sig_kernel_only(signr))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303 continue;
2304
2305 if (sig_kernel_stop(signr)) {
2306 /*
2307 * The default action is to stop all threads in
2308 * the thread group. The job control signals
2309 * do nothing in an orphaned pgrp, but SIGSTOP
2310 * always works. Note that siglock needs to be
2311 * dropped during the call to is_orphaned_pgrp()
2312 * because of lock ordering with tasklist_lock.
2313 * This allows an intervening SIGCONT to be posted.
2314 * We need to check for that and bail out if necessary.
2315 */
2316 if (signr != SIGSTOP) {
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002317 spin_unlock_irq(&sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318
2319 /* signals can be posted during this window */
2320
Eric W. Biederman3e7cd6c2007-02-12 00:52:58 -08002321 if (is_current_pgrp_orphaned())
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322 goto relock;
2323
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002324 spin_lock_irq(&sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002325 }
2326
Roland McGrath7bcf6a22008-07-25 19:45:53 -07002327 if (likely(do_signal_stop(info->si_signo))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328 /* It released the siglock. */
2329 goto relock;
2330 }
2331
2332 /*
2333 * We didn't actually stop, due to a race
2334 * with SIGCONT or something like that.
2335 */
2336 continue;
2337 }
2338
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002339 spin_unlock_irq(&sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002340
2341 /*
2342 * Anything else is fatal, maybe with a core dump.
2343 */
2344 current->flags |= PF_SIGNALED;
Oleg Nesterov2dce81b2008-04-30 00:52:58 -07002345
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346 if (sig_kernel_coredump(signr)) {
Oleg Nesterov2dce81b2008-04-30 00:52:58 -07002347 if (print_fatal_signals)
Roland McGrath7bcf6a22008-07-25 19:45:53 -07002348 print_fatal_signal(regs, info->si_signo);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349 /*
2350 * If it was able to dump core, this kills all
2351 * other threads in the group and synchronizes with
2352 * their demise. If we lost the race with another
2353 * thread getting here, it set group_exit_code
2354 * first and our do_group_exit call below will use
2355 * that value and ignore the one we pass it.
2356 */
Roland McGrath7bcf6a22008-07-25 19:45:53 -07002357 do_coredump(info->si_signo, info->si_signo, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358 }
2359
2360 /*
2361 * Death signals, no core dump.
2362 */
Roland McGrath7bcf6a22008-07-25 19:45:53 -07002363 do_group_exit(info->si_signo);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002364 /* NOTREACHED */
2365 }
Oleg Nesterovf6b76d42008-04-30 00:52:47 -07002366 spin_unlock_irq(&sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002367 return signr;
2368}
2369
Matt Fleming5e6292c2012-01-10 15:11:17 -08002370/**
Al Viroefee9842012-04-28 02:04:15 -04002371 * signal_delivered -
2372 * @sig: number of signal being delivered
2373 * @info: siginfo_t of signal being delivered
2374 * @ka: sigaction setting that chose the handler
2375 * @regs: user register state
2376 * @stepping: nonzero if debugger single-step or block-step in use
Matt Fleming5e6292c2012-01-10 15:11:17 -08002377 *
2378 * This function should be called when a signal has succesfully been
Al Viroefee9842012-04-28 02:04:15 -04002379 * delivered. It updates the blocked signals accordingly (@ka->sa.sa_mask
2380 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2381 * is set in @ka->sa.sa_flags. Tracing is notified.
Matt Fleming5e6292c2012-01-10 15:11:17 -08002382 */
Al Viroefee9842012-04-28 02:04:15 -04002383void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka,
2384 struct pt_regs *regs, int stepping)
Matt Fleming5e6292c2012-01-10 15:11:17 -08002385{
2386 sigset_t blocked;
2387
Al Viroa610d6e2012-05-21 23:42:15 -04002388 /* A signal was successfully delivered, and the
2389 saved sigmask was stored on the signal frame,
2390 and will be restored by sigreturn. So we can
2391 simply clear the restore sigmask flag. */
2392 clear_restore_sigmask();
2393
Matt Fleming5e6292c2012-01-10 15:11:17 -08002394 sigorsets(&blocked, &current->blocked, &ka->sa.sa_mask);
2395 if (!(ka->sa.sa_flags & SA_NODEFER))
Al Viroefee9842012-04-28 02:04:15 -04002396 sigaddset(&blocked, sig);
Matt Fleming5e6292c2012-01-10 15:11:17 -08002397 set_current_blocked(&blocked);
Al Viroefee9842012-04-28 02:04:15 -04002398 tracehook_signal_handler(sig, info, ka, regs, stepping);
Matt Fleming5e6292c2012-01-10 15:11:17 -08002399}
2400
Oleg Nesterov0edceb7bc2011-04-27 19:17:37 +02002401/*
2402 * It could be that complete_signal() picked us to notify about the
Oleg Nesterovfec99932011-04-27 19:50:21 +02002403 * group-wide signal. Other threads should be notified now to take
2404 * the shared signals in @which since we will not.
Oleg Nesterov0edceb7bc2011-04-27 19:17:37 +02002405 */
Oleg Nesterovf646e222011-04-27 19:18:39 +02002406static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
Oleg Nesterov0edceb7bc2011-04-27 19:17:37 +02002407{
Oleg Nesterovf646e222011-04-27 19:18:39 +02002408 sigset_t retarget;
Oleg Nesterov0edceb7bc2011-04-27 19:17:37 +02002409 struct task_struct *t;
2410
Oleg Nesterovf646e222011-04-27 19:18:39 +02002411 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2412 if (sigisemptyset(&retarget))
2413 return;
2414
Oleg Nesterov0edceb7bc2011-04-27 19:17:37 +02002415 t = tsk;
2416 while_each_thread(tsk, t) {
Oleg Nesterovfec99932011-04-27 19:50:21 +02002417 if (t->flags & PF_EXITING)
2418 continue;
2419
2420 if (!has_pending_signals(&retarget, &t->blocked))
2421 continue;
2422 /* Remove the signals this thread can handle. */
2423 sigandsets(&retarget, &retarget, &t->blocked);
2424
2425 if (!signal_pending(t))
2426 signal_wake_up(t, 0);
2427
2428 if (sigisemptyset(&retarget))
2429 break;
Oleg Nesterov0edceb7bc2011-04-27 19:17:37 +02002430 }
2431}
2432
Oleg Nesterovd12619b2008-02-08 04:19:12 -08002433void exit_signals(struct task_struct *tsk)
2434{
2435 int group_stop = 0;
Oleg Nesterovf646e222011-04-27 19:18:39 +02002436 sigset_t unblocked;
Oleg Nesterovd12619b2008-02-08 04:19:12 -08002437
Tejun Heo77e4ef92011-12-12 18:12:21 -08002438 /*
2439 * @tsk is about to have PF_EXITING set - lock out users which
2440 * expect stable threadgroup.
2441 */
2442 threadgroup_change_begin(tsk);
2443
Oleg Nesterov5dee1702008-02-08 04:19:13 -08002444 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2445 tsk->flags |= PF_EXITING;
Tejun Heo77e4ef92011-12-12 18:12:21 -08002446 threadgroup_change_end(tsk);
Oleg Nesterov5dee1702008-02-08 04:19:13 -08002447 return;
Oleg Nesterovd12619b2008-02-08 04:19:12 -08002448 }
2449
Oleg Nesterov5dee1702008-02-08 04:19:13 -08002450 spin_lock_irq(&tsk->sighand->siglock);
Oleg Nesterovd12619b2008-02-08 04:19:12 -08002451 /*
2452 * From now this task is not visible for group-wide signals,
2453 * see wants_signal(), do_signal_stop().
2454 */
2455 tsk->flags |= PF_EXITING;
Tejun Heo77e4ef92011-12-12 18:12:21 -08002456
2457 threadgroup_change_end(tsk);
2458
Oleg Nesterov5dee1702008-02-08 04:19:13 -08002459 if (!signal_pending(tsk))
2460 goto out;
2461
Oleg Nesterovf646e222011-04-27 19:18:39 +02002462 unblocked = tsk->blocked;
2463 signotset(&unblocked);
2464 retarget_shared_pending(tsk, &unblocked);
Oleg Nesterov5dee1702008-02-08 04:19:13 -08002465
Tejun Heoa8f072c2011-06-02 11:13:59 +02002466 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
Tejun Heoe5c19022011-03-23 10:37:00 +01002467 task_participate_group_stop(tsk))
Tejun Heoedf2ed12011-03-23 10:37:00 +01002468 group_stop = CLD_STOPPED;
Oleg Nesterov5dee1702008-02-08 04:19:13 -08002469out:
Oleg Nesterovd12619b2008-02-08 04:19:12 -08002470 spin_unlock_irq(&tsk->sighand->siglock);
2471
Tejun Heo62bcf9d2011-03-23 10:37:01 +01002472 /*
2473 * If group stop has completed, deliver the notification. This
2474 * should always go to the real parent of the group leader.
2475 */
Roland McGrathae6d2ed2009-09-23 15:56:53 -07002476 if (unlikely(group_stop)) {
Oleg Nesterovd12619b2008-02-08 04:19:12 -08002477 read_lock(&tasklist_lock);
Tejun Heo62bcf9d2011-03-23 10:37:01 +01002478 do_notify_parent_cldstop(tsk, false, group_stop);
Oleg Nesterovd12619b2008-02-08 04:19:12 -08002479 read_unlock(&tasklist_lock);
2480 }
2481}
2482
Linus Torvalds1da177e2005-04-16 15:20:36 -07002483EXPORT_SYMBOL(recalc_sigpending);
2484EXPORT_SYMBOL_GPL(dequeue_signal);
2485EXPORT_SYMBOL(flush_signals);
2486EXPORT_SYMBOL(force_sig);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002487EXPORT_SYMBOL(send_sig);
2488EXPORT_SYMBOL(send_sig_info);
2489EXPORT_SYMBOL(sigprocmask);
2490EXPORT_SYMBOL(block_all_signals);
2491EXPORT_SYMBOL(unblock_all_signals);
2492
2493
2494/*
2495 * System call entry points.
2496 */
2497
Randy Dunlap41c57892011-04-04 15:00:26 -07002498/**
2499 * sys_restart_syscall - restart a system call
2500 */
Heiko Carstens754fe8d2009-01-14 14:14:09 +01002501SYSCALL_DEFINE0(restart_syscall)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002502{
2503 struct restart_block *restart = &current_thread_info()->restart_block;
2504 return restart->fn(restart);
2505}
2506
2507long do_no_restart_syscall(struct restart_block *param)
2508{
2509 return -EINTR;
2510}
2511
Oleg Nesterovb1828012011-04-27 21:56:14 +02002512static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2513{
2514 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2515 sigset_t newblocked;
2516 /* A set of now blocked but previously unblocked signals. */
Oleg Nesterov702a5072011-04-27 22:01:27 +02002517 sigandnsets(&newblocked, newset, &current->blocked);
Oleg Nesterovb1828012011-04-27 21:56:14 +02002518 retarget_shared_pending(tsk, &newblocked);
2519 }
2520 tsk->blocked = *newset;
2521 recalc_sigpending();
2522}
2523
Oleg Nesterove6fa16a2011-04-27 20:59:41 +02002524/**
2525 * set_current_blocked - change current->blocked mask
2526 * @newset: new mask
2527 *
2528 * It is wrong to change ->blocked directly, this helper should be used
2529 * to ensure the process can't miss a shared signal we are going to block.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002530 */
Al Viro77097ae2012-04-27 13:58:59 -04002531void set_current_blocked(sigset_t *newset)
2532{
2533 struct task_struct *tsk = current;
2534 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2535 spin_lock_irq(&tsk->sighand->siglock);
2536 __set_task_blocked(tsk, newset);
2537 spin_unlock_irq(&tsk->sighand->siglock);
2538}
2539
2540void __set_current_blocked(const sigset_t *newset)
Oleg Nesterove6fa16a2011-04-27 20:59:41 +02002541{
2542 struct task_struct *tsk = current;
2543
2544 spin_lock_irq(&tsk->sighand->siglock);
Oleg Nesterovb1828012011-04-27 21:56:14 +02002545 __set_task_blocked(tsk, newset);
Oleg Nesterove6fa16a2011-04-27 20:59:41 +02002546 spin_unlock_irq(&tsk->sighand->siglock);
2547}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002548
2549/*
2550 * This is also useful for kernel threads that want to temporarily
2551 * (or permanently) block certain signals.
2552 *
2553 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2554 * interface happily blocks "unblockable" signals like SIGKILL
2555 * and friends.
2556 */
2557int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2558{
Oleg Nesterov73ef4ae2011-04-27 19:54:20 +02002559 struct task_struct *tsk = current;
2560 sigset_t newset;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002561
Oleg Nesterov73ef4ae2011-04-27 19:54:20 +02002562 /* Lockless, only current can change ->blocked, never from irq */
Oleg Nesterova26fd332006-03-23 03:00:49 -08002563 if (oldset)
Oleg Nesterov73ef4ae2011-04-27 19:54:20 +02002564 *oldset = tsk->blocked;
Oleg Nesterova26fd332006-03-23 03:00:49 -08002565
Linus Torvalds1da177e2005-04-16 15:20:36 -07002566 switch (how) {
2567 case SIG_BLOCK:
Oleg Nesterov73ef4ae2011-04-27 19:54:20 +02002568 sigorsets(&newset, &tsk->blocked, set);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002569 break;
2570 case SIG_UNBLOCK:
Oleg Nesterov702a5072011-04-27 22:01:27 +02002571 sigandnsets(&newset, &tsk->blocked, set);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002572 break;
2573 case SIG_SETMASK:
Oleg Nesterov73ef4ae2011-04-27 19:54:20 +02002574 newset = *set;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002575 break;
2576 default:
Oleg Nesterov73ef4ae2011-04-27 19:54:20 +02002577 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002578 }
Oleg Nesterova26fd332006-03-23 03:00:49 -08002579
Al Viro77097ae2012-04-27 13:58:59 -04002580 __set_current_blocked(&newset);
Oleg Nesterov73ef4ae2011-04-27 19:54:20 +02002581 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002582}
2583
Randy Dunlap41c57892011-04-04 15:00:26 -07002584/**
2585 * sys_rt_sigprocmask - change the list of currently blocked signals
2586 * @how: whether to add, remove, or set signals
Randy Dunlapada9c932011-06-14 15:50:11 -07002587 * @nset: stores pending signals
Randy Dunlap41c57892011-04-04 15:00:26 -07002588 * @oset: previous value of signal mask if non-null
2589 * @sigsetsize: size of sigset_t type
2590 */
Oleg Nesterovbb7efee2011-04-27 21:18:10 +02002591SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
Heiko Carstens17da2bd2009-01-14 14:14:10 +01002592 sigset_t __user *, oset, size_t, sigsetsize)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002593{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002594 sigset_t old_set, new_set;
Oleg Nesterovbb7efee2011-04-27 21:18:10 +02002595 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002596
2597 /* XXX: Don't preclude handling different sized sigset_t's. */
2598 if (sigsetsize != sizeof(sigset_t))
Oleg Nesterovbb7efee2011-04-27 21:18:10 +02002599 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002600
Oleg Nesterovbb7efee2011-04-27 21:18:10 +02002601 old_set = current->blocked;
2602
2603 if (nset) {
2604 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2605 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002606 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2607
Oleg Nesterovbb7efee2011-04-27 21:18:10 +02002608 error = sigprocmask(how, &new_set, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002609 if (error)
Oleg Nesterovbb7efee2011-04-27 21:18:10 +02002610 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002611 }
Oleg Nesterovbb7efee2011-04-27 21:18:10 +02002612
2613 if (oset) {
2614 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2615 return -EFAULT;
2616 }
2617
2618 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002619}
2620
2621long do_sigpending(void __user *set, unsigned long sigsetsize)
2622{
2623 long error = -EINVAL;
2624 sigset_t pending;
2625
2626 if (sigsetsize > sizeof(sigset_t))
2627 goto out;
2628
2629 spin_lock_irq(&current->sighand->siglock);
2630 sigorsets(&pending, &current->pending.signal,
2631 &current->signal->shared_pending.signal);
2632 spin_unlock_irq(&current->sighand->siglock);
2633
2634 /* Outside the lock because only this thread touches it. */
2635 sigandsets(&pending, &current->blocked, &pending);
2636
2637 error = -EFAULT;
2638 if (!copy_to_user(set, &pending, sigsetsize))
2639 error = 0;
2640
2641out:
2642 return error;
Randy Dunlap5aba0852011-04-04 14:59:31 -07002643}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002644
Randy Dunlap41c57892011-04-04 15:00:26 -07002645/**
2646 * sys_rt_sigpending - examine a pending signal that has been raised
2647 * while blocked
2648 * @set: stores pending signals
2649 * @sigsetsize: size of sigset_t type or larger
2650 */
Heiko Carstens17da2bd2009-01-14 14:14:10 +01002651SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002652{
2653 return do_sigpending(set, sigsetsize);
2654}
2655
2656#ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2657
2658int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
2659{
2660 int err;
2661
2662 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2663 return -EFAULT;
2664 if (from->si_code < 0)
2665 return __copy_to_user(to, from, sizeof(siginfo_t))
2666 ? -EFAULT : 0;
2667 /*
2668 * If you change siginfo_t structure, please be sure
2669 * this code is fixed accordingly.
Davide Libenzifba2afa2007-05-10 22:23:13 -07002670 * Please remember to update the signalfd_copyinfo() function
2671 * inside fs/signalfd.c too, in case siginfo_t changes.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002672 * It should never copy any pad contained in the structure
2673 * to avoid security leaks, but must copy the generic
2674 * 3 ints plus the relevant union member.
2675 */
2676 err = __put_user(from->si_signo, &to->si_signo);
2677 err |= __put_user(from->si_errno, &to->si_errno);
2678 err |= __put_user((short)from->si_code, &to->si_code);
2679 switch (from->si_code & __SI_MASK) {
2680 case __SI_KILL:
2681 err |= __put_user(from->si_pid, &to->si_pid);
2682 err |= __put_user(from->si_uid, &to->si_uid);
2683 break;
2684 case __SI_TIMER:
2685 err |= __put_user(from->si_tid, &to->si_tid);
2686 err |= __put_user(from->si_overrun, &to->si_overrun);
2687 err |= __put_user(from->si_ptr, &to->si_ptr);
2688 break;
2689 case __SI_POLL:
2690 err |= __put_user(from->si_band, &to->si_band);
2691 err |= __put_user(from->si_fd, &to->si_fd);
2692 break;
2693 case __SI_FAULT:
2694 err |= __put_user(from->si_addr, &to->si_addr);
2695#ifdef __ARCH_SI_TRAPNO
2696 err |= __put_user(from->si_trapno, &to->si_trapno);
2697#endif
Andi Kleena337fda2010-09-27 20:32:19 +02002698#ifdef BUS_MCEERR_AO
Randy Dunlap5aba0852011-04-04 14:59:31 -07002699 /*
Andi Kleena337fda2010-09-27 20:32:19 +02002700 * Other callers might not initialize the si_lsb field,
Randy Dunlap5aba0852011-04-04 14:59:31 -07002701 * so check explicitly for the right codes here.
Andi Kleena337fda2010-09-27 20:32:19 +02002702 */
2703 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
2704 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2705#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002706 break;
2707 case __SI_CHLD:
2708 err |= __put_user(from->si_pid, &to->si_pid);
2709 err |= __put_user(from->si_uid, &to->si_uid);
2710 err |= __put_user(from->si_status, &to->si_status);
2711 err |= __put_user(from->si_utime, &to->si_utime);
2712 err |= __put_user(from->si_stime, &to->si_stime);
2713 break;
2714 case __SI_RT: /* This is not generated by the kernel as of now. */
2715 case __SI_MESGQ: /* But this is */
2716 err |= __put_user(from->si_pid, &to->si_pid);
2717 err |= __put_user(from->si_uid, &to->si_uid);
2718 err |= __put_user(from->si_ptr, &to->si_ptr);
2719 break;
Will Drewrya0727e82012-04-12 16:48:00 -05002720#ifdef __ARCH_SIGSYS
2721 case __SI_SYS:
2722 err |= __put_user(from->si_call_addr, &to->si_call_addr);
2723 err |= __put_user(from->si_syscall, &to->si_syscall);
2724 err |= __put_user(from->si_arch, &to->si_arch);
2725 break;
2726#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002727 default: /* this is just in case for now ... */
2728 err |= __put_user(from->si_pid, &to->si_pid);
2729 err |= __put_user(from->si_uid, &to->si_uid);
2730 break;
2731 }
2732 return err;
2733}
2734
2735#endif
2736
Randy Dunlap41c57892011-04-04 15:00:26 -07002737/**
Oleg Nesterov943df142011-04-27 21:44:14 +02002738 * do_sigtimedwait - wait for queued signals specified in @which
2739 * @which: queued signals to wait for
2740 * @info: if non-null, the signal's siginfo is returned here
2741 * @ts: upper bound on process time suspension
2742 */
2743int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
2744 const struct timespec *ts)
2745{
2746 struct task_struct *tsk = current;
2747 long timeout = MAX_SCHEDULE_TIMEOUT;
2748 sigset_t mask = *which;
2749 int sig;
2750
2751 if (ts) {
2752 if (!timespec_valid(ts))
2753 return -EINVAL;
2754 timeout = timespec_to_jiffies(ts);
2755 /*
2756 * We can be close to the next tick, add another one
2757 * to ensure we will wait at least the time asked for.
2758 */
2759 if (ts->tv_sec || ts->tv_nsec)
2760 timeout++;
2761 }
2762
2763 /*
2764 * Invert the set of allowed signals to get those we want to block.
2765 */
2766 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
2767 signotset(&mask);
2768
2769 spin_lock_irq(&tsk->sighand->siglock);
2770 sig = dequeue_signal(tsk, &mask, info);
2771 if (!sig && timeout) {
2772 /*
2773 * None ready, temporarily unblock those we're interested
2774 * while we are sleeping in so that we'll be awakened when
Oleg Nesterovb1828012011-04-27 21:56:14 +02002775 * they arrive. Unblocking is always fine, we can avoid
2776 * set_current_blocked().
Oleg Nesterov943df142011-04-27 21:44:14 +02002777 */
2778 tsk->real_blocked = tsk->blocked;
2779 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
2780 recalc_sigpending();
2781 spin_unlock_irq(&tsk->sighand->siglock);
2782
2783 timeout = schedule_timeout_interruptible(timeout);
2784
2785 spin_lock_irq(&tsk->sighand->siglock);
Oleg Nesterovb1828012011-04-27 21:56:14 +02002786 __set_task_blocked(tsk, &tsk->real_blocked);
Oleg Nesterov943df142011-04-27 21:44:14 +02002787 siginitset(&tsk->real_blocked, 0);
Oleg Nesterovb1828012011-04-27 21:56:14 +02002788 sig = dequeue_signal(tsk, &mask, info);
Oleg Nesterov943df142011-04-27 21:44:14 +02002789 }
2790 spin_unlock_irq(&tsk->sighand->siglock);
2791
2792 if (sig)
2793 return sig;
2794 return timeout ? -EINTR : -EAGAIN;
2795}
2796
2797/**
Randy Dunlap41c57892011-04-04 15:00:26 -07002798 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2799 * in @uthese
2800 * @uthese: queued signals to wait for
2801 * @uinfo: if non-null, the signal's siginfo is returned here
2802 * @uts: upper bound on process time suspension
2803 * @sigsetsize: size of sigset_t type
2804 */
Heiko Carstens17da2bd2009-01-14 14:14:10 +01002805SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2806 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2807 size_t, sigsetsize)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002808{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002809 sigset_t these;
2810 struct timespec ts;
2811 siginfo_t info;
Oleg Nesterov943df142011-04-27 21:44:14 +02002812 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002813
2814 /* XXX: Don't preclude handling different sized sigset_t's. */
2815 if (sigsetsize != sizeof(sigset_t))
2816 return -EINVAL;
2817
2818 if (copy_from_user(&these, uthese, sizeof(these)))
2819 return -EFAULT;
Randy Dunlap5aba0852011-04-04 14:59:31 -07002820
Linus Torvalds1da177e2005-04-16 15:20:36 -07002821 if (uts) {
2822 if (copy_from_user(&ts, uts, sizeof(ts)))
2823 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002824 }
2825
Oleg Nesterov943df142011-04-27 21:44:14 +02002826 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002827
Oleg Nesterov943df142011-04-27 21:44:14 +02002828 if (ret > 0 && uinfo) {
2829 if (copy_siginfo_to_user(uinfo, &info))
2830 ret = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002831 }
2832
2833 return ret;
2834}
2835
Randy Dunlap41c57892011-04-04 15:00:26 -07002836/**
2837 * sys_kill - send a signal to a process
2838 * @pid: the PID of the process
2839 * @sig: signal to be sent
2840 */
Heiko Carstens17da2bd2009-01-14 14:14:10 +01002841SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002842{
2843 struct siginfo info;
2844
2845 info.si_signo = sig;
2846 info.si_errno = 0;
2847 info.si_code = SI_USER;
Pavel Emelyanovb4888932007-10-18 23:40:14 -07002848 info.si_pid = task_tgid_vnr(current);
Eric W. Biederman078de5f2012-02-08 07:00:08 -08002849 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
Linus Torvalds1da177e2005-04-16 15:20:36 -07002850
2851 return kill_something_info(sig, &info, pid);
2852}
2853
Thomas Gleixner30b4ae82009-04-04 21:01:01 +00002854static int
2855do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002856{
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002857 struct task_struct *p;
Thomas Gleixner30b4ae82009-04-04 21:01:01 +00002858 int error = -ESRCH;
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002859
Oleg Nesterov3547ff32008-04-30 00:52:51 -07002860 rcu_read_lock();
Pavel Emelyanov228ebcb2007-10-18 23:40:16 -07002861 p = find_task_by_vpid(pid);
Pavel Emelyanovb4888932007-10-18 23:40:14 -07002862 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
Thomas Gleixner30b4ae82009-04-04 21:01:01 +00002863 error = check_kill_permission(sig, info, p);
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002864 /*
2865 * The null signal is a permissions and process existence
2866 * probe. No signal is actually delivered.
2867 */
Oleg Nesterov4a30deb2009-09-23 15:57:00 -07002868 if (!error && sig) {
2869 error = do_send_sig_info(sig, info, p, false);
2870 /*
2871 * If lock_task_sighand() failed we pretend the task
2872 * dies after receiving the signal. The window is tiny,
2873 * and the signal is private anyway.
2874 */
2875 if (unlikely(error == -ESRCH))
2876 error = 0;
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002877 }
2878 }
Oleg Nesterov3547ff32008-04-30 00:52:51 -07002879 rcu_read_unlock();
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002880
2881 return error;
2882}
2883
Thomas Gleixner30b4ae82009-04-04 21:01:01 +00002884static int do_tkill(pid_t tgid, pid_t pid, int sig)
2885{
2886 struct siginfo info;
2887
2888 info.si_signo = sig;
2889 info.si_errno = 0;
2890 info.si_code = SI_TKILL;
2891 info.si_pid = task_tgid_vnr(current);
Eric W. Biederman078de5f2012-02-08 07:00:08 -08002892 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
Thomas Gleixner30b4ae82009-04-04 21:01:01 +00002893
2894 return do_send_specific(tgid, pid, sig, &info);
2895}
2896
Linus Torvalds1da177e2005-04-16 15:20:36 -07002897/**
2898 * sys_tgkill - send signal to one specific thread
2899 * @tgid: the thread group ID of the thread
2900 * @pid: the PID of the thread
2901 * @sig: signal to be sent
2902 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08002903 * This syscall also checks the @tgid and returns -ESRCH even if the PID
Linus Torvalds1da177e2005-04-16 15:20:36 -07002904 * exists but it's not belonging to the target process anymore. This
2905 * method solves the problem of threads exiting and PIDs getting reused.
2906 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +01002907SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002908{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002909 /* This is only valid for single tasks */
2910 if (pid <= 0 || tgid <= 0)
2911 return -EINVAL;
2912
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002913 return do_tkill(tgid, pid, sig);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002914}
2915
Randy Dunlap41c57892011-04-04 15:00:26 -07002916/**
2917 * sys_tkill - send signal to one specific task
2918 * @pid: the PID of the task
2919 * @sig: signal to be sent
2920 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07002921 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2922 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +01002923SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002924{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002925 /* This is only valid for single tasks */
2926 if (pid <= 0)
2927 return -EINVAL;
2928
Vadim Lobanov6dd69f12005-10-30 15:02:18 -08002929 return do_tkill(0, pid, sig);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002930}
2931
Randy Dunlap41c57892011-04-04 15:00:26 -07002932/**
2933 * sys_rt_sigqueueinfo - send signal information to a signal
2934 * @pid: the PID of the thread
2935 * @sig: signal to be sent
2936 * @uinfo: signal info to be sent
2937 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +01002938SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
2939 siginfo_t __user *, uinfo)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002940{
2941 siginfo_t info;
2942
2943 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2944 return -EFAULT;
2945
2946 /* Not even root can pretend to send signals from the kernel.
Julien Tinnesda485242011-03-18 15:05:21 -07002947 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2948 */
Roland Dreier243b4222011-03-28 14:13:35 -07002949 if (info.si_code >= 0 || info.si_code == SI_TKILL) {
Julien Tinnesda485242011-03-18 15:05:21 -07002950 /* We used to allow any < 0 si_code */
2951 WARN_ON_ONCE(info.si_code < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002952 return -EPERM;
Julien Tinnesda485242011-03-18 15:05:21 -07002953 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002954 info.si_signo = sig;
2955
2956 /* POSIX.1b doesn't mention process groups. */
2957 return kill_proc_info(sig, &info, pid);
2958}
2959
Thomas Gleixner62ab4502009-04-04 21:01:06 +00002960long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
2961{
2962 /* This is only valid for single tasks */
2963 if (pid <= 0 || tgid <= 0)
2964 return -EINVAL;
2965
2966 /* Not even root can pretend to send signals from the kernel.
Julien Tinnesda485242011-03-18 15:05:21 -07002967 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2968 */
Roland Dreier243b4222011-03-28 14:13:35 -07002969 if (info->si_code >= 0 || info->si_code == SI_TKILL) {
Julien Tinnesda485242011-03-18 15:05:21 -07002970 /* We used to allow any < 0 si_code */
2971 WARN_ON_ONCE(info->si_code < 0);
Thomas Gleixner62ab4502009-04-04 21:01:06 +00002972 return -EPERM;
Julien Tinnesda485242011-03-18 15:05:21 -07002973 }
Thomas Gleixner62ab4502009-04-04 21:01:06 +00002974 info->si_signo = sig;
2975
2976 return do_send_specific(tgid, pid, sig, info);
2977}
2978
2979SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
2980 siginfo_t __user *, uinfo)
2981{
2982 siginfo_t info;
2983
2984 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2985 return -EFAULT;
2986
2987 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
2988}
2989
Oleg Nesterov88531f72006-03-28 16:11:24 -08002990int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002991{
Pavel Emelyanov93585ee2008-04-30 00:52:39 -07002992 struct task_struct *t = current;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002993 struct k_sigaction *k;
George Anzinger71fabd52006-01-08 01:02:48 -08002994 sigset_t mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002995
Jesper Juhl7ed20e12005-05-01 08:59:14 -07002996 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002997 return -EINVAL;
2998
Pavel Emelyanov93585ee2008-04-30 00:52:39 -07002999 k = &t->sighand->action[sig-1];
Linus Torvalds1da177e2005-04-16 15:20:36 -07003000
3001 spin_lock_irq(&current->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003002 if (oact)
3003 *oact = *k;
3004
3005 if (act) {
Oleg Nesterov9ac95f22006-02-09 22:41:50 +03003006 sigdelsetmask(&act->sa.sa_mask,
3007 sigmask(SIGKILL) | sigmask(SIGSTOP));
Oleg Nesterov88531f72006-03-28 16:11:24 -08003008 *k = *act;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003009 /*
3010 * POSIX 3.3.1.3:
3011 * "Setting a signal action to SIG_IGN for a signal that is
3012 * pending shall cause the pending signal to be discarded,
3013 * whether or not it is blocked."
3014 *
3015 * "Setting a signal action to SIG_DFL for a signal that is
3016 * pending and whose default action is to ignore the signal
3017 * (for example, SIGCHLD), shall cause the pending signal to
3018 * be discarded, whether or not it is blocked"
3019 */
Roland McGrath35de2542008-07-25 19:45:51 -07003020 if (sig_handler_ignored(sig_handler(t, sig), sig)) {
George Anzinger71fabd52006-01-08 01:02:48 -08003021 sigemptyset(&mask);
3022 sigaddset(&mask, sig);
3023 rm_from_queue_full(&mask, &t->signal->shared_pending);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003024 do {
George Anzinger71fabd52006-01-08 01:02:48 -08003025 rm_from_queue_full(&mask, &t->pending);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003026 t = next_thread(t);
3027 } while (t != current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003028 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003029 }
3030
3031 spin_unlock_irq(&current->sighand->siglock);
3032 return 0;
3033}
3034
3035int
3036do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
3037{
3038 stack_t oss;
3039 int error;
3040
Linus Torvalds0083fc22009-08-01 10:34:56 -07003041 oss.ss_sp = (void __user *) current->sas_ss_sp;
3042 oss.ss_size = current->sas_ss_size;
3043 oss.ss_flags = sas_ss_flags(sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003044
3045 if (uss) {
3046 void __user *ss_sp;
3047 size_t ss_size;
3048 int ss_flags;
3049
3050 error = -EFAULT;
Linus Torvalds0dd84862009-08-01 11:18:56 -07003051 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
3052 goto out;
3053 error = __get_user(ss_sp, &uss->ss_sp) |
3054 __get_user(ss_flags, &uss->ss_flags) |
3055 __get_user(ss_size, &uss->ss_size);
3056 if (error)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003057 goto out;
3058
3059 error = -EPERM;
3060 if (on_sig_stack(sp))
3061 goto out;
3062
3063 error = -EINVAL;
3064 /*
Randy Dunlap5aba0852011-04-04 14:59:31 -07003065 * Note - this code used to test ss_flags incorrectly:
Linus Torvalds1da177e2005-04-16 15:20:36 -07003066 * old code may have been written using ss_flags==0
3067 * to mean ss_flags==SS_ONSTACK (as this was the only
3068 * way that worked) - this fix preserves that older
Randy Dunlap5aba0852011-04-04 14:59:31 -07003069 * mechanism.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003070 */
3071 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
3072 goto out;
3073
3074 if (ss_flags == SS_DISABLE) {
3075 ss_size = 0;
3076 ss_sp = NULL;
3077 } else {
3078 error = -ENOMEM;
3079 if (ss_size < MINSIGSTKSZ)
3080 goto out;
3081 }
3082
3083 current->sas_ss_sp = (unsigned long) ss_sp;
3084 current->sas_ss_size = ss_size;
3085 }
3086
Linus Torvalds0083fc22009-08-01 10:34:56 -07003087 error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003088 if (uoss) {
3089 error = -EFAULT;
Linus Torvalds0083fc22009-08-01 10:34:56 -07003090 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07003091 goto out;
Linus Torvalds0083fc22009-08-01 10:34:56 -07003092 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
3093 __put_user(oss.ss_size, &uoss->ss_size) |
3094 __put_user(oss.ss_flags, &uoss->ss_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003095 }
3096
Linus Torvalds1da177e2005-04-16 15:20:36 -07003097out:
3098 return error;
3099}
3100
3101#ifdef __ARCH_WANT_SYS_SIGPENDING
3102
Randy Dunlap41c57892011-04-04 15:00:26 -07003103/**
3104 * sys_sigpending - examine pending signals
3105 * @set: where mask of pending signal is returned
3106 */
Heiko Carstensb290ebe2009-01-14 14:14:06 +01003107SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003108{
3109 return do_sigpending(set, sizeof(*set));
3110}
3111
3112#endif
3113
3114#ifdef __ARCH_WANT_SYS_SIGPROCMASK
Randy Dunlap41c57892011-04-04 15:00:26 -07003115/**
3116 * sys_sigprocmask - examine and change blocked signals
3117 * @how: whether to add, remove, or set signals
Oleg Nesterovb013c392011-04-28 11:36:20 +02003118 * @nset: signals to add or remove (if non-null)
Randy Dunlap41c57892011-04-04 15:00:26 -07003119 * @oset: previous value of signal mask if non-null
3120 *
Randy Dunlap5aba0852011-04-04 14:59:31 -07003121 * Some platforms have their own version with special arguments;
3122 * others support only sys_rt_sigprocmask.
3123 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07003124
Oleg Nesterovb013c392011-04-28 11:36:20 +02003125SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
Heiko Carstensb290ebe2009-01-14 14:14:06 +01003126 old_sigset_t __user *, oset)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003127{
Linus Torvalds1da177e2005-04-16 15:20:36 -07003128 old_sigset_t old_set, new_set;
Oleg Nesterov2e4f7c72011-05-09 13:48:56 +02003129 sigset_t new_blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003130
Oleg Nesterovb013c392011-04-28 11:36:20 +02003131 old_set = current->blocked.sig[0];
3132
3133 if (nset) {
3134 if (copy_from_user(&new_set, nset, sizeof(*nset)))
3135 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003136 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
3137
Oleg Nesterov2e4f7c72011-05-09 13:48:56 +02003138 new_blocked = current->blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003139
Linus Torvalds1da177e2005-04-16 15:20:36 -07003140 switch (how) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003141 case SIG_BLOCK:
Oleg Nesterov2e4f7c72011-05-09 13:48:56 +02003142 sigaddsetmask(&new_blocked, new_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003143 break;
3144 case SIG_UNBLOCK:
Oleg Nesterov2e4f7c72011-05-09 13:48:56 +02003145 sigdelsetmask(&new_blocked, new_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003146 break;
3147 case SIG_SETMASK:
Oleg Nesterov2e4f7c72011-05-09 13:48:56 +02003148 new_blocked.sig[0] = new_set;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003149 break;
Oleg Nesterov2e4f7c72011-05-09 13:48:56 +02003150 default:
3151 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003152 }
3153
Al Viro77097ae2012-04-27 13:58:59 -04003154 __set_current_blocked(&new_blocked);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003155 }
Oleg Nesterovb013c392011-04-28 11:36:20 +02003156
3157 if (oset) {
3158 if (copy_to_user(oset, &old_set, sizeof(*oset)))
3159 return -EFAULT;
3160 }
3161
3162 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003163}
3164#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3165
3166#ifdef __ARCH_WANT_SYS_RT_SIGACTION
Randy Dunlap41c57892011-04-04 15:00:26 -07003167/**
3168 * sys_rt_sigaction - alter an action taken by a process
3169 * @sig: signal to be sent
Randy Dunlapf9fa0bc2011-04-08 10:53:46 -07003170 * @act: new sigaction
3171 * @oact: used to save the previous sigaction
Randy Dunlap41c57892011-04-04 15:00:26 -07003172 * @sigsetsize: size of sigset_t type
3173 */
Heiko Carstensd4e82042009-01-14 14:14:34 +01003174SYSCALL_DEFINE4(rt_sigaction, int, sig,
3175 const struct sigaction __user *, act,
3176 struct sigaction __user *, oact,
3177 size_t, sigsetsize)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003178{
3179 struct k_sigaction new_sa, old_sa;
3180 int ret = -EINVAL;
3181
3182 /* XXX: Don't preclude handling different sized sigset_t's. */
3183 if (sigsetsize != sizeof(sigset_t))
3184 goto out;
3185
3186 if (act) {
3187 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
3188 return -EFAULT;
3189 }
3190
3191 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
3192
3193 if (!ret && oact) {
3194 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
3195 return -EFAULT;
3196 }
3197out:
3198 return ret;
3199}
3200#endif /* __ARCH_WANT_SYS_RT_SIGACTION */
3201
3202#ifdef __ARCH_WANT_SYS_SGETMASK
3203
3204/*
3205 * For backwards compatibility. Functionality superseded by sigprocmask.
3206 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +01003207SYSCALL_DEFINE0(sgetmask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003208{
3209 /* SMP safe */
3210 return current->blocked.sig[0];
3211}
3212
Heiko Carstensa5f8fa92009-01-14 14:14:11 +01003213SYSCALL_DEFINE1(ssetmask, int, newmask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003214{
Oleg Nesterovc1095c62011-07-27 12:49:44 -07003215 int old = current->blocked.sig[0];
3216 sigset_t newset;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003217
Oleg Nesterovc1095c62011-07-27 12:49:44 -07003218 set_current_blocked(&newset);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003219
3220 return old;
3221}
3222#endif /* __ARCH_WANT_SGETMASK */
3223
3224#ifdef __ARCH_WANT_SYS_SIGNAL
3225/*
3226 * For backwards compatibility. Functionality superseded by sigaction.
3227 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +01003228SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003229{
3230 struct k_sigaction new_sa, old_sa;
3231 int ret;
3232
3233 new_sa.sa.sa_handler = handler;
3234 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
Oleg Nesterovc70d3d702006-02-09 22:41:41 +03003235 sigemptyset(&new_sa.sa.sa_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003236
3237 ret = do_sigaction(sig, &new_sa, &old_sa);
3238
3239 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
3240}
3241#endif /* __ARCH_WANT_SYS_SIGNAL */
3242
3243#ifdef __ARCH_WANT_SYS_PAUSE
3244
Heiko Carstensa5f8fa92009-01-14 14:14:11 +01003245SYSCALL_DEFINE0(pause)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003246{
Oleg Nesterovd92fcf02011-05-25 19:22:27 +02003247 while (!signal_pending(current)) {
3248 current->state = TASK_INTERRUPTIBLE;
3249 schedule();
3250 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003251 return -ERESTARTNOHAND;
3252}
3253
3254#endif
3255
Al Viro68f3f162012-05-21 21:42:32 -04003256int sigsuspend(sigset_t *set)
3257{
Al Viro68f3f162012-05-21 21:42:32 -04003258 current->saved_sigmask = current->blocked;
3259 set_current_blocked(set);
3260
3261 current->state = TASK_INTERRUPTIBLE;
3262 schedule();
3263 set_restore_sigmask();
3264 return -ERESTARTNOHAND;
3265}
Al Viro68f3f162012-05-21 21:42:32 -04003266
David Woodhouse150256d2006-01-18 17:43:57 -08003267#ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
Randy Dunlap41c57892011-04-04 15:00:26 -07003268/**
3269 * sys_rt_sigsuspend - replace the signal mask for a value with the
3270 * @unewset value until a signal is received
3271 * @unewset: new signal mask value
3272 * @sigsetsize: size of sigset_t type
3273 */
Heiko Carstensd4e82042009-01-14 14:14:34 +01003274SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
David Woodhouse150256d2006-01-18 17:43:57 -08003275{
3276 sigset_t newset;
3277
3278 /* XXX: Don't preclude handling different sized sigset_t's. */
3279 if (sigsetsize != sizeof(sigset_t))
3280 return -EINVAL;
3281
3282 if (copy_from_user(&newset, unewset, sizeof(newset)))
3283 return -EFAULT;
Al Viro68f3f162012-05-21 21:42:32 -04003284 return sigsuspend(&newset);
David Woodhouse150256d2006-01-18 17:43:57 -08003285}
3286#endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
3287
David Howellsf269fdd2006-09-27 01:50:23 -07003288__attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
3289{
3290 return NULL;
3291}
3292
Linus Torvalds1da177e2005-04-16 15:20:36 -07003293void __init signals_init(void)
3294{
Christoph Lameter0a31bd52007-05-06 14:49:57 -07003295 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003296}
Jason Wessel67fc4e02010-05-20 21:04:21 -05003297
3298#ifdef CONFIG_KGDB_KDB
3299#include <linux/kdb.h>
3300/*
3301 * kdb_send_sig_info - Allows kdb to send signals without exposing
3302 * signal internals. This function checks if the required locks are
3303 * available before calling the main signal code, to avoid kdb
3304 * deadlocks.
3305 */
3306void
3307kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
3308{
3309 static struct task_struct *kdb_prev_t;
3310 int sig, new_t;
3311 if (!spin_trylock(&t->sighand->siglock)) {
3312 kdb_printf("Can't do kill command now.\n"
3313 "The sigmask lock is held somewhere else in "
3314 "kernel, try again later\n");
3315 return;
3316 }
3317 spin_unlock(&t->sighand->siglock);
3318 new_t = kdb_prev_t != t;
3319 kdb_prev_t = t;
3320 if (t->state != TASK_RUNNING && new_t) {
3321 kdb_printf("Process is not RUNNING, sending a signal from "
3322 "kdb risks deadlock\n"
3323 "on the run queue locks. "
3324 "The signal has _not_ been sent.\n"
3325 "Reissue the kill command if you want to risk "
3326 "the deadlock.\n");
3327 return;
3328 }
3329 sig = info->si_signo;
3330 if (send_sig_info(sig, info, t))
3331 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3332 sig, t->pid);
3333 else
3334 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
3335}
3336#endif /* CONFIG_KGDB_KDB */