1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SIGNAL_H
3 #define _LINUX_SIGNAL_H
4 
5 #include <linux/bug.h>
6 #include <linux/signal_types.h>
7 #include <linux/string.h>
8 
9 struct task_struct;
10 
11 /* for sysctl */
12 extern int print_fatal_signals;
13 
copy_siginfo(kernel_siginfo_t * to,const kernel_siginfo_t * from)14 static inline void copy_siginfo(kernel_siginfo_t *to,
15 				const kernel_siginfo_t *from)
16 {
17 	memcpy(to, from, sizeof(*to));
18 }
19 
clear_siginfo(kernel_siginfo_t * info)20 static inline void clear_siginfo(kernel_siginfo_t *info)
21 {
22 	memset(info, 0, sizeof(*info));
23 }
24 
25 #define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))
26 
copy_siginfo_to_external(siginfo_t * to,const kernel_siginfo_t * from)27 static inline void copy_siginfo_to_external(siginfo_t *to,
28 					    const kernel_siginfo_t *from)
29 {
30 	memcpy(to, from, sizeof(*from));
31 	memset(((char *)to) + sizeof(struct kernel_siginfo), 0,
32 		SI_EXPANSION_SIZE);
33 }
34 
35 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
36 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
37 
38 enum siginfo_layout {
39 	SIL_KILL,
40 	SIL_TIMER,
41 	SIL_POLL,
42 	SIL_FAULT,
43 	SIL_FAULT_TRAPNO,
44 	SIL_FAULT_MCEERR,
45 	SIL_FAULT_BNDERR,
46 	SIL_FAULT_PKUERR,
47 	SIL_FAULT_PERF_EVENT,
48 	SIL_CHLD,
49 	SIL_RT,
50 	SIL_SYS,
51 };
52 
53 enum siginfo_layout siginfo_layout(unsigned sig, int si_code);
54 
55 /*
56  * Define some primitives to manipulate sigset_t.
57  */
58 
59 #ifndef __HAVE_ARCH_SIG_BITOPS
60 #include <linux/bitops.h>
61 
62 /* We don't use <linux/bitops.h> for these because there is no need to
63    be atomic.  */
sigaddset(sigset_t * set,int _sig)64 static inline void sigaddset(sigset_t *set, int _sig)
65 {
66 	unsigned long sig = _sig - 1;
67 	if (_NSIG_WORDS == 1)
68 		set->sig[0] |= 1UL << sig;
69 	else
70 		set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
71 }
72 
sigdelset(sigset_t * set,int _sig)73 static inline void sigdelset(sigset_t *set, int _sig)
74 {
75 	unsigned long sig = _sig - 1;
76 	if (_NSIG_WORDS == 1)
77 		set->sig[0] &= ~(1UL << sig);
78 	else
79 		set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
80 }
81 
sigismember(sigset_t * set,int _sig)82 static inline int sigismember(sigset_t *set, int _sig)
83 {
84 	unsigned long sig = _sig - 1;
85 	if (_NSIG_WORDS == 1)
86 		return 1 & (set->sig[0] >> sig);
87 	else
88 		return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
89 }
90 
91 #endif /* __HAVE_ARCH_SIG_BITOPS */
92 
sigisemptyset(sigset_t * set)93 static inline int sigisemptyset(sigset_t *set)
94 {
95 	switch (_NSIG_WORDS) {
96 	case 4:
97 		return (set->sig[3] | set->sig[2] |
98 			set->sig[1] | set->sig[0]) == 0;
99 	case 2:
100 		return (set->sig[1] | set->sig[0]) == 0;
101 	case 1:
102 		return set->sig[0] == 0;
103 	default:
104 		BUILD_BUG();
105 		return 0;
106 	}
107 }
108 
sigequalsets(const sigset_t * set1,const sigset_t * set2)109 static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2)
110 {
111 	switch (_NSIG_WORDS) {
112 	case 4:
113 		return	(set1->sig[3] == set2->sig[3]) &&
114 			(set1->sig[2] == set2->sig[2]) &&
115 			(set1->sig[1] == set2->sig[1]) &&
116 			(set1->sig[0] == set2->sig[0]);
117 	case 2:
118 		return	(set1->sig[1] == set2->sig[1]) &&
119 			(set1->sig[0] == set2->sig[0]);
120 	case 1:
121 		return	set1->sig[0] == set2->sig[0];
122 	}
123 	return 0;
124 }
125 
126 #define sigmask(sig)	(1UL << ((sig) - 1))
127 
128 #ifndef __HAVE_ARCH_SIG_SETOPS
129 
130 #define _SIG_SET_BINOP(name, op)					\
131 static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
132 {									\
133 	unsigned long a0, a1, a2, a3, b0, b1, b2, b3;			\
134 									\
135 	switch (_NSIG_WORDS) {						\
136 	case 4:								\
137 		a3 = a->sig[3]; a2 = a->sig[2];				\
138 		b3 = b->sig[3]; b2 = b->sig[2];				\
139 		r->sig[3] = op(a3, b3);					\
140 		r->sig[2] = op(a2, b2);					\
141 		fallthrough;						\
142 	case 2:								\
143 		a1 = a->sig[1]; b1 = b->sig[1];				\
144 		r->sig[1] = op(a1, b1);					\
145 		fallthrough;						\
146 	case 1:								\
147 		a0 = a->sig[0]; b0 = b->sig[0];				\
148 		r->sig[0] = op(a0, b0);					\
149 		break;							\
150 	default:							\
151 		BUILD_BUG();						\
152 	}								\
153 }
154 
155 #define _sig_or(x,y)	((x) | (y))
_SIG_SET_BINOP(sigorsets,_sig_or)156 _SIG_SET_BINOP(sigorsets, _sig_or)
157 
158 #define _sig_and(x,y)	((x) & (y))
159 _SIG_SET_BINOP(sigandsets, _sig_and)
160 
161 #define _sig_andn(x,y)	((x) & ~(y))
162 _SIG_SET_BINOP(sigandnsets, _sig_andn)
163 
164 #undef _SIG_SET_BINOP
165 #undef _sig_or
166 #undef _sig_and
167 #undef _sig_andn
168 
169 #define _SIG_SET_OP(name, op)						\
170 static inline void name(sigset_t *set)					\
171 {									\
172 	switch (_NSIG_WORDS) {						\
173 	case 4:	set->sig[3] = op(set->sig[3]);				\
174 		set->sig[2] = op(set->sig[2]);				\
175 		fallthrough;						\
176 	case 2:	set->sig[1] = op(set->sig[1]);				\
177 		fallthrough;						\
178 	case 1:	set->sig[0] = op(set->sig[0]);				\
179 		    break;						\
180 	default:							\
181 		BUILD_BUG();						\
182 	}								\
183 }
184 
185 #define _sig_not(x)	(~(x))
186 _SIG_SET_OP(signotset, _sig_not)
187 
188 #undef _SIG_SET_OP
189 #undef _sig_not
190 
191 static inline void sigemptyset(sigset_t *set)
192 {
193 	switch (_NSIG_WORDS) {
194 	default:
195 		memset(set, 0, sizeof(sigset_t));
196 		break;
197 	case 2: set->sig[1] = 0;
198 		fallthrough;
199 	case 1:	set->sig[0] = 0;
200 		break;
201 	}
202 }
203 
sigfillset(sigset_t * set)204 static inline void sigfillset(sigset_t *set)
205 {
206 	switch (_NSIG_WORDS) {
207 	default:
208 		memset(set, -1, sizeof(sigset_t));
209 		break;
210 	case 2: set->sig[1] = -1;
211 		fallthrough;
212 	case 1:	set->sig[0] = -1;
213 		break;
214 	}
215 }
216 
217 /* Some extensions for manipulating the low 32 signals in particular.  */
218 
sigaddsetmask(sigset_t * set,unsigned long mask)219 static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
220 {
221 	set->sig[0] |= mask;
222 }
223 
sigdelsetmask(sigset_t * set,unsigned long mask)224 static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
225 {
226 	set->sig[0] &= ~mask;
227 }
228 
sigtestsetmask(sigset_t * set,unsigned long mask)229 static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
230 {
231 	return (set->sig[0] & mask) != 0;
232 }
233 
siginitset(sigset_t * set,unsigned long mask)234 static inline void siginitset(sigset_t *set, unsigned long mask)
235 {
236 	set->sig[0] = mask;
237 	switch (_NSIG_WORDS) {
238 	default:
239 		memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
240 		break;
241 	case 2: set->sig[1] = 0;
242 		break;
243 	case 1: ;
244 	}
245 }
246 
siginitsetinv(sigset_t * set,unsigned long mask)247 static inline void siginitsetinv(sigset_t *set, unsigned long mask)
248 {
249 	set->sig[0] = ~mask;
250 	switch (_NSIG_WORDS) {
251 	default:
252 		memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1));
253 		break;
254 	case 2: set->sig[1] = -1;
255 		break;
256 	case 1: ;
257 	}
258 }
259 
260 #endif /* __HAVE_ARCH_SIG_SETOPS */
261 
init_sigpending(struct sigpending * sig)262 static inline void init_sigpending(struct sigpending *sig)
263 {
264 	sigemptyset(&sig->signal);
265 	INIT_LIST_HEAD(&sig->list);
266 }
267 
268 extern void flush_sigqueue(struct sigpending *queue);
269 
270 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
valid_signal(unsigned long sig)271 static inline int valid_signal(unsigned long sig)
272 {
273 	return sig <= _NSIG ? 1 : 0;
274 }
275 
276 struct timespec;
277 struct pt_regs;
278 enum pid_type;
279 
280 extern int next_signal(struct sigpending *pending, sigset_t *mask);
281 extern int do_send_sig_info(int sig, struct kernel_siginfo *info,
282 				struct task_struct *p, enum pid_type type);
283 extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
284 			       struct task_struct *p, enum pid_type type);
285 extern int send_signal_locked(int sig, struct kernel_siginfo *info,
286 			      struct task_struct *p, enum pid_type type);
287 extern int sigprocmask(int, sigset_t *, sigset_t *);
288 extern void set_current_blocked(sigset_t *);
289 extern void __set_current_blocked(const sigset_t *);
290 extern int show_unhandled_signals;
291 
292 extern bool get_signal(struct ksignal *ksig);
293 extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
294 extern void exit_signals(struct task_struct *tsk);
295 extern void kernel_sigaction(int, __sighandler_t);
296 
297 #define SIG_KTHREAD ((__force __sighandler_t)2)
298 #define SIG_KTHREAD_KERNEL ((__force __sighandler_t)3)
299 
allow_signal(int sig)300 static inline void allow_signal(int sig)
301 {
302 	/*
303 	 * Kernel threads handle their own signals. Let the signal code
304 	 * know it'll be handled, so that they don't get converted to
305 	 * SIGKILL or just silently dropped.
306 	 */
307 	kernel_sigaction(sig, SIG_KTHREAD);
308 }
309 
allow_kernel_signal(int sig)310 static inline void allow_kernel_signal(int sig)
311 {
312 	/*
313 	 * Kernel threads handle their own signals. Let the signal code
314 	 * know signals sent by the kernel will be handled, so that they
315 	 * don't get silently dropped.
316 	 */
317 	kernel_sigaction(sig, SIG_KTHREAD_KERNEL);
318 }
319 
disallow_signal(int sig)320 static inline void disallow_signal(int sig)
321 {
322 	kernel_sigaction(sig, SIG_IGN);
323 }
324 
325 extern struct kmem_cache *sighand_cachep;
326 
327 extern bool unhandled_signal(struct task_struct *tsk, int sig);
328 
329 /*
330  * In POSIX a signal is sent either to a specific thread (Linux task)
331  * or to the process as a whole (Linux thread group).  How the signal
332  * is sent determines whether it's to one thread or the whole group,
333  * which determines which signal mask(s) are involved in blocking it
334  * from being delivered until later.  When the signal is delivered,
335  * either it's caught or ignored by a user handler or it has a default
336  * effect that applies to the whole thread group (POSIX process).
337  *
338  * The possible effects an unblocked signal set to SIG_DFL can have are:
339  *   ignore	- Nothing Happens
340  *   terminate	- kill the process, i.e. all threads in the group,
341  * 		  similar to exit_group.  The group leader (only) reports
342  *		  WIFSIGNALED status to its parent.
343  *   coredump	- write a core dump file describing all threads using
344  *		  the same mm and then kill all those threads
345  *   stop 	- stop all the threads in the group, i.e. TASK_STOPPED state
346  *
347  * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
348  * Other signals when not blocked and set to SIG_DFL behaves as follows.
349  * The job control signals also have other special effects.
350  *
351  *	+--------------------+------------------+
352  *	|  POSIX signal      |  default action  |
353  *	+--------------------+------------------+
354  *	|  SIGHUP            |  terminate	|
355  *	|  SIGINT            |	terminate	|
356  *	|  SIGQUIT           |	coredump 	|
357  *	|  SIGILL            |	coredump 	|
358  *	|  SIGTRAP           |	coredump 	|
359  *	|  SIGABRT/SIGIOT    |	coredump 	|
360  *	|  SIGBUS            |	coredump 	|
361  *	|  SIGFPE            |	coredump 	|
362  *	|  SIGKILL           |	terminate(+)	|
363  *	|  SIGUSR1           |	terminate	|
364  *	|  SIGSEGV           |	coredump 	|
365  *	|  SIGUSR2           |	terminate	|
366  *	|  SIGPIPE           |	terminate	|
367  *	|  SIGALRM           |	terminate	|
368  *	|  SIGTERM           |	terminate	|
369  *	|  SIGCHLD           |	ignore   	|
370  *	|  SIGCONT           |	ignore(*)	|
371  *	|  SIGSTOP           |	stop(*)(+)  	|
372  *	|  SIGTSTP           |	stop(*)  	|
373  *	|  SIGTTIN           |	stop(*)  	|
374  *	|  SIGTTOU           |	stop(*)  	|
375  *	|  SIGURG            |	ignore   	|
376  *	|  SIGXCPU           |	coredump 	|
377  *	|  SIGXFSZ           |	coredump 	|
378  *	|  SIGVTALRM         |	terminate	|
379  *	|  SIGPROF           |	terminate	|
380  *	|  SIGPOLL/SIGIO     |	terminate	|
381  *	|  SIGSYS/SIGUNUSED  |	coredump 	|
382  *	|  SIGSTKFLT         |	terminate	|
383  *	|  SIGWINCH          |	ignore   	|
384  *	|  SIGPWR            |	terminate	|
385  *	|  SIGRTMIN-SIGRTMAX |	terminate       |
386  *	+--------------------+------------------+
387  *	|  non-POSIX signal  |  default action  |
388  *	+--------------------+------------------+
389  *	|  SIGEMT            |  coredump	|
390  *	+--------------------+------------------+
391  *
392  * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
393  * (*) Special job control effects:
394  * When SIGCONT is sent, it resumes the process (all threads in the group)
395  * from TASK_STOPPED state and also clears any pending/queued stop signals
396  * (any of those marked with "stop(*)").  This happens regardless of blocking,
397  * catching, or ignoring SIGCONT.  When any stop signal is sent, it clears
398  * any pending/queued SIGCONT signals; this happens regardless of blocking,
399  * catching, or ignored the stop signal, though (except for SIGSTOP) the
400  * default action of stopping the process may happen later or never.
401  */
402 
403 #ifdef SIGEMT
404 #define SIGEMT_MASK	rt_sigmask(SIGEMT)
405 #else
406 #define SIGEMT_MASK	0
407 #endif
408 
409 #if SIGRTMIN > BITS_PER_LONG
410 #define rt_sigmask(sig)	(1ULL << ((sig)-1))
411 #else
412 #define rt_sigmask(sig)	sigmask(sig)
413 #endif
414 
415 #define siginmask(sig, mask) \
416 	((sig) > 0 && (sig) < SIGRTMIN && (rt_sigmask(sig) & (mask)))
417 
418 #define SIG_KERNEL_ONLY_MASK (\
419 	rt_sigmask(SIGKILL)   |  rt_sigmask(SIGSTOP))
420 
421 #define SIG_KERNEL_STOP_MASK (\
422 	rt_sigmask(SIGSTOP)   |  rt_sigmask(SIGTSTP)   | \
423 	rt_sigmask(SIGTTIN)   |  rt_sigmask(SIGTTOU)   )
424 
425 #define SIG_KERNEL_COREDUMP_MASK (\
426         rt_sigmask(SIGQUIT)   |  rt_sigmask(SIGILL)    | \
427 	rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGABRT)   | \
428         rt_sigmask(SIGFPE)    |  rt_sigmask(SIGSEGV)   | \
429 	rt_sigmask(SIGBUS)    |  rt_sigmask(SIGSYS)    | \
430         rt_sigmask(SIGXCPU)   |  rt_sigmask(SIGXFSZ)   | \
431 	SIGEMT_MASK				       )
432 
433 #define SIG_KERNEL_IGNORE_MASK (\
434         rt_sigmask(SIGCONT)   |  rt_sigmask(SIGCHLD)   | \
435 	rt_sigmask(SIGWINCH)  |  rt_sigmask(SIGURG)    )
436 
437 #define SIG_SPECIFIC_SICODES_MASK (\
438 	rt_sigmask(SIGILL)    |  rt_sigmask(SIGFPE)    | \
439 	rt_sigmask(SIGSEGV)   |  rt_sigmask(SIGBUS)    | \
440 	rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGCHLD)   | \
441 	rt_sigmask(SIGPOLL)   |  rt_sigmask(SIGSYS)    | \
442 	SIGEMT_MASK                                    )
443 
444 #define sig_kernel_only(sig)		siginmask(sig, SIG_KERNEL_ONLY_MASK)
445 #define sig_kernel_coredump(sig)	siginmask(sig, SIG_KERNEL_COREDUMP_MASK)
446 #define sig_kernel_ignore(sig)		siginmask(sig, SIG_KERNEL_IGNORE_MASK)
447 #define sig_kernel_stop(sig)		siginmask(sig, SIG_KERNEL_STOP_MASK)
448 #define sig_specific_sicodes(sig)	siginmask(sig, SIG_SPECIFIC_SICODES_MASK)
449 
450 #define sig_fatal(t, signr) \
451 	(!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
452 	 (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
453 
454 void signals_init(void);
455 
456 int restore_altstack(const stack_t __user *);
457 int __save_altstack(stack_t __user *, unsigned long);
458 
459 #define unsafe_save_altstack(uss, sp, label) do { \
460 	stack_t __user *__uss = uss; \
461 	struct task_struct *t = current; \
462 	unsafe_put_user((void __user *)t->sas_ss_sp, &__uss->ss_sp, label); \
463 	unsafe_put_user(t->sas_ss_flags, &__uss->ss_flags, label); \
464 	unsafe_put_user(t->sas_ss_size, &__uss->ss_size, label); \
465 } while (0);
466 
467 #ifdef CONFIG_DYNAMIC_SIGFRAME
468 bool sigaltstack_size_valid(size_t ss_size);
469 #else
sigaltstack_size_valid(size_t size)470 static inline bool sigaltstack_size_valid(size_t size) { return true; }
471 #endif /* !CONFIG_DYNAMIC_SIGFRAME */
472 
473 #ifdef CONFIG_PROC_FS
474 struct seq_file;
475 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
476 #endif
477 
478 #ifndef arch_untagged_si_addr
479 /*
480  * Given a fault address and a signal and si_code which correspond to the
481  * _sigfault union member, returns the address that must appear in si_addr if
482  * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags.
483  */
arch_untagged_si_addr(void __user * addr,unsigned long sig,unsigned long si_code)484 static inline void __user *arch_untagged_si_addr(void __user *addr,
485 						 unsigned long sig,
486 						 unsigned long si_code)
487 {
488 	return addr;
489 }
490 #endif
491 
492 #endif /* _LINUX_SIGNAL_H */
493