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
9struct task_struct;
10
11/* for sysctl */
12extern int print_fatal_signals;
13
14static inline void copy_siginfo(kernel_siginfo_t *to,
15 const kernel_siginfo_t *from)
16{
17 memcpy(to, from, sizeof(*to));
18}
19
20static 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
27static 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
35int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
36int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
37
38enum 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
53enum 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. */
64static 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
73static 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
82static 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
93static 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
109static 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) \
131static 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))
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) \
170static 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
191static 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
204static 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
219static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
220{
221 set->sig[0] |= mask;
222}
223
224static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
225{
226 set->sig[0] &= ~mask;
227}
228
229static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
230{
231 return (set->sig[0] & mask) != 0;
232}
233
234static 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
247static 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
262static inline void init_sigpending(struct sigpending *sig)
263{
264 sigemptyset(&sig->signal);
265 INIT_LIST_HEAD(&sig->list);
266}
267
268extern void flush_sigqueue(struct sigpending *queue);
269
270/* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
271static inline int valid_signal(unsigned long sig)
272{
273 return sig <= _NSIG ? 1 : 0;
274}
275
276struct timespec;
277struct pt_regs;
278enum pid_type;
279
280extern int next_signal(struct sigpending *pending, sigset_t *mask);
281extern int do_send_sig_info(int sig, struct kernel_siginfo *info,
282 struct task_struct *p, enum pid_type type);
283extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
284 struct task_struct *p, enum pid_type type);
285extern int send_signal_locked(int sig, struct kernel_siginfo *info,
286 struct task_struct *p, enum pid_type type);
287extern int sigprocmask(int, sigset_t *, sigset_t *);
288extern void set_current_blocked(sigset_t *);
289extern void __set_current_blocked(const sigset_t *);
290extern int show_unhandled_signals;
291
292extern bool get_signal(struct ksignal *ksig);
293extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
294extern void exit_signals(struct task_struct *tsk);
295extern 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
300static 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
310static 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
320static inline void disallow_signal(int sig)
321{
322 kernel_sigaction(sig, SIG_IGN);
323}
324
325extern struct kmem_cache *sighand_cachep;
326
327extern 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
454void signals_init(void);
455
456int restore_altstack(const stack_t __user *);
457int __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
468bool sigaltstack_size_valid(size_t ss_size);
469#else
470static inline bool sigaltstack_size_valid(size_t size) { return true; }
471#endif /* !CONFIG_DYNAMIC_SIGFRAME */
472
473#ifdef CONFIG_PROC_FS
474struct seq_file;
475extern 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 */
484static 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

source code of linux/include/linux/signal.h