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1 #ifndef _LINUX_SIGNAL_H
2 #define _LINUX_SIGNAL_H
3 
4 #include <linux/list.h>
5 #include <linux/bug.h>
6 #include <uapi/linux/signal.h>
7 
8 struct task_struct;
9 
10 /* for sysctl */
11 extern int print_fatal_signals;
12 /*
13  * Real Time signals may be queued.
14  */
15 
16 struct sigqueue {
17 	struct list_head list;
18 	int flags;
19 	siginfo_t info;
20 	struct user_struct *user;
21 };
22 
23 /* flags values. */
24 #define SIGQUEUE_PREALLOC	1
25 
26 struct sigpending {
27 	struct list_head list;
28 	sigset_t signal;
29 };
30 
31 /*
32  * Define some primitives to manipulate sigset_t.
33  */
34 
35 #ifndef __HAVE_ARCH_SIG_BITOPS
36 #include <linux/bitops.h>
37 
38 /* We don't use <linux/bitops.h> for these because there is no need to
39    be atomic.  */
sigaddset(sigset_t * set,int _sig)40 static inline void sigaddset(sigset_t *set, int _sig)
41 {
42 	unsigned long sig = _sig - 1;
43 	if (_NSIG_WORDS == 1)
44 		set->sig[0] |= 1UL << sig;
45 	else
46 		set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
47 }
48 
sigdelset(sigset_t * set,int _sig)49 static inline void sigdelset(sigset_t *set, int _sig)
50 {
51 	unsigned long sig = _sig - 1;
52 	if (_NSIG_WORDS == 1)
53 		set->sig[0] &= ~(1UL << sig);
54 	else
55 		set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
56 }
57 
sigismember(sigset_t * set,int _sig)58 static inline int sigismember(sigset_t *set, int _sig)
59 {
60 	unsigned long sig = _sig - 1;
61 	if (_NSIG_WORDS == 1)
62 		return 1 & (set->sig[0] >> sig);
63 	else
64 		return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
65 }
66 
67 #endif /* __HAVE_ARCH_SIG_BITOPS */
68 
sigisemptyset(sigset_t * set)69 static inline int sigisemptyset(sigset_t *set)
70 {
71 	switch (_NSIG_WORDS) {
72 	case 4:
73 		return (set->sig[3] | set->sig[2] |
74 			set->sig[1] | set->sig[0]) == 0;
75 	case 2:
76 		return (set->sig[1] | set->sig[0]) == 0;
77 	case 1:
78 		return set->sig[0] == 0;
79 	default:
80 		BUILD_BUG();
81 		return 0;
82 	}
83 }
84 
85 #define sigmask(sig)	(1UL << ((sig) - 1))
86 
87 #ifndef __HAVE_ARCH_SIG_SETOPS
88 #include <linux/string.h>
89 
90 #define _SIG_SET_BINOP(name, op)					\
91 static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
92 {									\
93 	unsigned long a0, a1, a2, a3, b0, b1, b2, b3;			\
94 									\
95 	switch (_NSIG_WORDS) {						\
96 	case 4:								\
97 		a3 = a->sig[3]; a2 = a->sig[2];				\
98 		b3 = b->sig[3]; b2 = b->sig[2];				\
99 		r->sig[3] = op(a3, b3);					\
100 		r->sig[2] = op(a2, b2);					\
101 	case 2:								\
102 		a1 = a->sig[1]; b1 = b->sig[1];				\
103 		r->sig[1] = op(a1, b1);					\
104 	case 1:								\
105 		a0 = a->sig[0]; b0 = b->sig[0];				\
106 		r->sig[0] = op(a0, b0);					\
107 		break;							\
108 	default:							\
109 		BUILD_BUG();						\
110 	}								\
111 }
112 
113 #define _sig_or(x,y)	((x) | (y))
_SIG_SET_BINOP(sigorsets,_sig_or)114 _SIG_SET_BINOP(sigorsets, _sig_or)
115 
116 #define _sig_and(x,y)	((x) & (y))
117 _SIG_SET_BINOP(sigandsets, _sig_and)
118 
119 #define _sig_andn(x,y)	((x) & ~(y))
120 _SIG_SET_BINOP(sigandnsets, _sig_andn)
121 
122 #undef _SIG_SET_BINOP
123 #undef _sig_or
124 #undef _sig_and
125 #undef _sig_andn
126 
127 #define _SIG_SET_OP(name, op)						\
128 static inline void name(sigset_t *set)					\
129 {									\
130 	switch (_NSIG_WORDS) {						\
131 	case 4:	set->sig[3] = op(set->sig[3]);				\
132 		set->sig[2] = op(set->sig[2]);				\
133 	case 2:	set->sig[1] = op(set->sig[1]);				\
134 	case 1:	set->sig[0] = op(set->sig[0]);				\
135 		    break;						\
136 	default:							\
137 		BUILD_BUG();						\
138 	}								\
139 }
140 
141 #define _sig_not(x)	(~(x))
142 _SIG_SET_OP(signotset, _sig_not)
143 
144 #undef _SIG_SET_OP
145 #undef _sig_not
146 
147 static inline void sigemptyset(sigset_t *set)
148 {
149 	switch (_NSIG_WORDS) {
150 	default:
151 		memset(set, 0, sizeof(sigset_t));
152 		break;
153 	case 2: set->sig[1] = 0;
154 	case 1:	set->sig[0] = 0;
155 		break;
156 	}
157 }
158 
sigfillset(sigset_t * set)159 static inline void sigfillset(sigset_t *set)
160 {
161 	switch (_NSIG_WORDS) {
162 	default:
163 		memset(set, -1, sizeof(sigset_t));
164 		break;
165 	case 2: set->sig[1] = -1;
166 	case 1:	set->sig[0] = -1;
167 		break;
168 	}
169 }
170 
171 /* Some extensions for manipulating the low 32 signals in particular.  */
172 
sigaddsetmask(sigset_t * set,unsigned long mask)173 static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
174 {
175 	set->sig[0] |= mask;
176 }
177 
sigdelsetmask(sigset_t * set,unsigned long mask)178 static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
179 {
180 	set->sig[0] &= ~mask;
181 }
182 
sigtestsetmask(sigset_t * set,unsigned long mask)183 static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
184 {
185 	return (set->sig[0] & mask) != 0;
186 }
187 
siginitset(sigset_t * set,unsigned long mask)188 static inline void siginitset(sigset_t *set, unsigned long mask)
189 {
190 	set->sig[0] = mask;
191 	switch (_NSIG_WORDS) {
192 	default:
193 		memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
194 		break;
195 	case 2: set->sig[1] = 0;
196 	case 1: ;
197 	}
198 }
199 
siginitsetinv(sigset_t * set,unsigned long mask)200 static inline void siginitsetinv(sigset_t *set, unsigned long mask)
201 {
202 	set->sig[0] = ~mask;
203 	switch (_NSIG_WORDS) {
204 	default:
205 		memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1));
206 		break;
207 	case 2: set->sig[1] = -1;
208 	case 1: ;
209 	}
210 }
211 
212 #endif /* __HAVE_ARCH_SIG_SETOPS */
213 
init_sigpending(struct sigpending * sig)214 static inline void init_sigpending(struct sigpending *sig)
215 {
216 	sigemptyset(&sig->signal);
217 	INIT_LIST_HEAD(&sig->list);
218 }
219 
220 extern void flush_sigqueue(struct sigpending *queue);
221 
222 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
valid_signal(unsigned long sig)223 static inline int valid_signal(unsigned long sig)
224 {
225 	return sig <= _NSIG ? 1 : 0;
226 }
227 
228 struct timespec;
229 struct pt_regs;
230 
231 extern int next_signal(struct sigpending *pending, sigset_t *mask);
232 extern int do_send_sig_info(int sig, struct siginfo *info,
233 				struct task_struct *p, bool group);
234 extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
235 extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
236 extern int do_sigtimedwait(const sigset_t *, siginfo_t *,
237 				const struct timespec *);
238 extern int sigprocmask(int, sigset_t *, sigset_t *);
239 extern void set_current_blocked(sigset_t *);
240 extern void __set_current_blocked(const sigset_t *);
241 extern int show_unhandled_signals;
242 extern int sigsuspend(sigset_t *);
243 
244 struct sigaction {
245 #ifndef __ARCH_HAS_IRIX_SIGACTION
246 	__sighandler_t	sa_handler;
247 	unsigned long	sa_flags;
248 #else
249 	unsigned int	sa_flags;
250 	__sighandler_t	sa_handler;
251 #endif
252 #ifdef __ARCH_HAS_SA_RESTORER
253 	__sigrestore_t sa_restorer;
254 #endif
255 	sigset_t	sa_mask;	/* mask last for extensibility */
256 };
257 
258 struct k_sigaction {
259 	struct sigaction sa;
260 #ifdef __ARCH_HAS_KA_RESTORER
261 	__sigrestore_t ka_restorer;
262 #endif
263 };
264 
265 #ifdef CONFIG_OLD_SIGACTION
266 struct old_sigaction {
267 	__sighandler_t sa_handler;
268 	old_sigset_t sa_mask;
269 	unsigned long sa_flags;
270 	__sigrestore_t sa_restorer;
271 };
272 #endif
273 
274 struct ksignal {
275 	struct k_sigaction ka;
276 	siginfo_t info;
277 	int sig;
278 };
279 
280 extern int get_signal(struct ksignal *ksig);
281 extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
282 extern void exit_signals(struct task_struct *tsk);
283 extern void kernel_sigaction(int, __sighandler_t);
284 
allow_signal(int sig)285 static inline void allow_signal(int sig)
286 {
287 	/*
288 	 * Kernel threads handle their own signals. Let the signal code
289 	 * know it'll be handled, so that they don't get converted to
290 	 * SIGKILL or just silently dropped.
291 	 */
292 	kernel_sigaction(sig, (__force __sighandler_t)2);
293 }
294 
disallow_signal(int sig)295 static inline void disallow_signal(int sig)
296 {
297 	kernel_sigaction(sig, SIG_IGN);
298 }
299 
300 extern struct kmem_cache *sighand_cachep;
301 
302 int unhandled_signal(struct task_struct *tsk, int sig);
303 
304 /*
305  * In POSIX a signal is sent either to a specific thread (Linux task)
306  * or to the process as a whole (Linux thread group).  How the signal
307  * is sent determines whether it's to one thread or the whole group,
308  * which determines which signal mask(s) are involved in blocking it
309  * from being delivered until later.  When the signal is delivered,
310  * either it's caught or ignored by a user handler or it has a default
311  * effect that applies to the whole thread group (POSIX process).
312  *
313  * The possible effects an unblocked signal set to SIG_DFL can have are:
314  *   ignore	- Nothing Happens
315  *   terminate	- kill the process, i.e. all threads in the group,
316  * 		  similar to exit_group.  The group leader (only) reports
317  *		  WIFSIGNALED status to its parent.
318  *   coredump	- write a core dump file describing all threads using
319  *		  the same mm and then kill all those threads
320  *   stop 	- stop all the threads in the group, i.e. TASK_STOPPED state
321  *
322  * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
323  * Other signals when not blocked and set to SIG_DFL behaves as follows.
324  * The job control signals also have other special effects.
325  *
326  *	+--------------------+------------------+
327  *	|  POSIX signal      |  default action  |
328  *	+--------------------+------------------+
329  *	|  SIGHUP            |  terminate	|
330  *	|  SIGINT            |	terminate	|
331  *	|  SIGQUIT           |	coredump 	|
332  *	|  SIGILL            |	coredump 	|
333  *	|  SIGTRAP           |	coredump 	|
334  *	|  SIGABRT/SIGIOT    |	coredump 	|
335  *	|  SIGBUS            |	coredump 	|
336  *	|  SIGFPE            |	coredump 	|
337  *	|  SIGKILL           |	terminate(+)	|
338  *	|  SIGUSR1           |	terminate	|
339  *	|  SIGSEGV           |	coredump 	|
340  *	|  SIGUSR2           |	terminate	|
341  *	|  SIGPIPE           |	terminate	|
342  *	|  SIGALRM           |	terminate	|
343  *	|  SIGTERM           |	terminate	|
344  *	|  SIGCHLD           |	ignore   	|
345  *	|  SIGCONT           |	ignore(*)	|
346  *	|  SIGSTOP           |	stop(*)(+)  	|
347  *	|  SIGTSTP           |	stop(*)  	|
348  *	|  SIGTTIN           |	stop(*)  	|
349  *	|  SIGTTOU           |	stop(*)  	|
350  *	|  SIGURG            |	ignore   	|
351  *	|  SIGXCPU           |	coredump 	|
352  *	|  SIGXFSZ           |	coredump 	|
353  *	|  SIGVTALRM         |	terminate	|
354  *	|  SIGPROF           |	terminate	|
355  *	|  SIGPOLL/SIGIO     |	terminate	|
356  *	|  SIGSYS/SIGUNUSED  |	coredump 	|
357  *	|  SIGSTKFLT         |	terminate	|
358  *	|  SIGWINCH          |	ignore   	|
359  *	|  SIGPWR            |	terminate	|
360  *	|  SIGRTMIN-SIGRTMAX |	terminate       |
361  *	+--------------------+------------------+
362  *	|  non-POSIX signal  |  default action  |
363  *	+--------------------+------------------+
364  *	|  SIGEMT            |  coredump	|
365  *	+--------------------+------------------+
366  *
367  * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
368  * (*) Special job control effects:
369  * When SIGCONT is sent, it resumes the process (all threads in the group)
370  * from TASK_STOPPED state and also clears any pending/queued stop signals
371  * (any of those marked with "stop(*)").  This happens regardless of blocking,
372  * catching, or ignoring SIGCONT.  When any stop signal is sent, it clears
373  * any pending/queued SIGCONT signals; this happens regardless of blocking,
374  * catching, or ignored the stop signal, though (except for SIGSTOP) the
375  * default action of stopping the process may happen later or never.
376  */
377 
378 #ifdef SIGEMT
379 #define SIGEMT_MASK	rt_sigmask(SIGEMT)
380 #else
381 #define SIGEMT_MASK	0
382 #endif
383 
384 #if SIGRTMIN > BITS_PER_LONG
385 #define rt_sigmask(sig)	(1ULL << ((sig)-1))
386 #else
387 #define rt_sigmask(sig)	sigmask(sig)
388 #endif
389 #define siginmask(sig, mask) (rt_sigmask(sig) & (mask))
390 
391 #define SIG_KERNEL_ONLY_MASK (\
392 	rt_sigmask(SIGKILL)   |  rt_sigmask(SIGSTOP))
393 
394 #define SIG_KERNEL_STOP_MASK (\
395 	rt_sigmask(SIGSTOP)   |  rt_sigmask(SIGTSTP)   | \
396 	rt_sigmask(SIGTTIN)   |  rt_sigmask(SIGTTOU)   )
397 
398 #define SIG_KERNEL_COREDUMP_MASK (\
399         rt_sigmask(SIGQUIT)   |  rt_sigmask(SIGILL)    | \
400 	rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGABRT)   | \
401         rt_sigmask(SIGFPE)    |  rt_sigmask(SIGSEGV)   | \
402 	rt_sigmask(SIGBUS)    |  rt_sigmask(SIGSYS)    | \
403         rt_sigmask(SIGXCPU)   |  rt_sigmask(SIGXFSZ)   | \
404 	SIGEMT_MASK				       )
405 
406 #define SIG_KERNEL_IGNORE_MASK (\
407         rt_sigmask(SIGCONT)   |  rt_sigmask(SIGCHLD)   | \
408 	rt_sigmask(SIGWINCH)  |  rt_sigmask(SIGURG)    )
409 
410 #define sig_kernel_only(sig) \
411 	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_ONLY_MASK))
412 #define sig_kernel_coredump(sig) \
413 	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_COREDUMP_MASK))
414 #define sig_kernel_ignore(sig) \
415 	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_IGNORE_MASK))
416 #define sig_kernel_stop(sig) \
417 	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_STOP_MASK))
418 
419 #define sig_user_defined(t, signr) \
420 	(((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) &&	\
421 	 ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))
422 
423 #define sig_fatal(t, signr) \
424 	(!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
425 	 (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
426 
427 void signals_init(void);
428 
429 int restore_altstack(const stack_t __user *);
430 int __save_altstack(stack_t __user *, unsigned long);
431 
432 #define save_altstack_ex(uss, sp) do { \
433 	stack_t __user *__uss = uss; \
434 	struct task_struct *t = current; \
435 	put_user_ex((void __user *)t->sas_ss_sp, &__uss->ss_sp); \
436 	put_user_ex(sas_ss_flags(sp), &__uss->ss_flags); \
437 	put_user_ex(t->sas_ss_size, &__uss->ss_size); \
438 } while (0);
439 
440 #ifdef CONFIG_PROC_FS
441 struct seq_file;
442 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
443 #endif
444 
445 #endif /* _LINUX_SIGNAL_H */
446