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/list.h>
7#include <linux/signal_types.h>
8#include <linux/string.h>
9
10struct task_struct;
11
12/* for sysctl */
13extern int print_fatal_signals;
14
15static inline void copy_siginfo(kernel_siginfo_t *to,
16 const kernel_siginfo_t *from)
17{
18 memcpy(to, from, len: sizeof(*to));
19}
20
21static inline void clear_siginfo(kernel_siginfo_t *info)
22{
23 memset(s: info, c: 0, n: sizeof(*info));
24}
25
26#define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))
27
28static inline void copy_siginfo_to_external(siginfo_t *to,
29 const kernel_siginfo_t *from)
30{
31 memcpy(to, from, len: sizeof(*from));
32 memset(s: ((char *)to) + sizeof(struct kernel_siginfo), c: 0,
33 SI_EXPANSION_SIZE);
34}
35
36int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
37int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
38
39enum siginfo_layout {
40 SIL_KILL,
41 SIL_TIMER,
42 SIL_POLL,
43 SIL_FAULT,
44 SIL_FAULT_TRAPNO,
45 SIL_FAULT_MCEERR,
46 SIL_FAULT_BNDERR,
47 SIL_FAULT_PKUERR,
48 SIL_FAULT_PERF_EVENT,
49 SIL_CHLD,
50 SIL_RT,
51 SIL_SYS,
52};
53
54enum siginfo_layout siginfo_layout(unsigned sig, int si_code);
55
56/*
57 * Define some primitives to manipulate sigset_t.
58 */
59
60#ifndef __HAVE_ARCH_SIG_BITOPS
61#include <linux/bitops.h>
62
63/* We don't use <linux/bitops.h> for these because there is no need to
64 be atomic. */
65static inline void sigaddset(sigset_t *set, int _sig)
66{
67 unsigned long sig = _sig - 1;
68 if (_NSIG_WORDS == 1)
69 set->sig[0] |= 1UL << sig;
70 else
71 set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
72}
73
74static inline void sigdelset(sigset_t *set, int _sig)
75{
76 unsigned long sig = _sig - 1;
77 if (_NSIG_WORDS == 1)
78 set->sig[0] &= ~(1UL << sig);
79 else
80 set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
81}
82
83static inline int sigismember(sigset_t *set, int _sig)
84{
85 unsigned long sig = _sig - 1;
86 if (_NSIG_WORDS == 1)
87 return 1 & (set->sig[0] >> sig);
88 else
89 return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
90}
91
92#endif /* __HAVE_ARCH_SIG_BITOPS */
93
94static inline int sigisemptyset(sigset_t *set)
95{
96 switch (_NSIG_WORDS) {
97 case 4:
98 return (set->sig[3] | set->sig[2] |
99 set->sig[1] | set->sig[0]) == 0;
100 case 2:
101 return (set->sig[1] | set->sig[0]) == 0;
102 case 1:
103 return set->sig[0] == 0;
104 default:
105 BUILD_BUG();
106 return 0;
107 }
108}
109
110static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2)
111{
112 switch (_NSIG_WORDS) {
113 case 4:
114 return (set1->sig[3] == set2->sig[3]) &&
115 (set1->sig[2] == set2->sig[2]) &&
116 (set1->sig[1] == set2->sig[1]) &&
117 (set1->sig[0] == set2->sig[0]);
118 case 2:
119 return (set1->sig[1] == set2->sig[1]) &&
120 (set1->sig[0] == set2->sig[0]);
121 case 1:
122 return set1->sig[0] == set2->sig[0];
123 }
124 return 0;
125}
126
127#define sigmask(sig) (1UL << ((sig) - 1))
128
129#ifndef __HAVE_ARCH_SIG_SETOPS
130
131#define _SIG_SET_BINOP(name, op) \
132static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
133{ \
134 unsigned long a0, a1, a2, a3, b0, b1, b2, b3; \
135 \
136 switch (_NSIG_WORDS) { \
137 case 4: \
138 a3 = a->sig[3]; a2 = a->sig[2]; \
139 b3 = b->sig[3]; b2 = b->sig[2]; \
140 r->sig[3] = op(a3, b3); \
141 r->sig[2] = op(a2, b2); \
142 fallthrough; \
143 case 2: \
144 a1 = a->sig[1]; b1 = b->sig[1]; \
145 r->sig[1] = op(a1, b1); \
146 fallthrough; \
147 case 1: \
148 a0 = a->sig[0]; b0 = b->sig[0]; \
149 r->sig[0] = op(a0, b0); \
150 break; \
151 default: \
152 BUILD_BUG(); \
153 } \
154}
155
156#define _sig_or(x,y) ((x) | (y))
157_SIG_SET_BINOP(sigorsets, _sig_or)
158
159#define _sig_and(x,y) ((x) & (y))
160_SIG_SET_BINOP(sigandsets, _sig_and)
161
162#define _sig_andn(x,y) ((x) & ~(y))
163_SIG_SET_BINOP(sigandnsets, _sig_andn)
164
165#undef _SIG_SET_BINOP
166#undef _sig_or
167#undef _sig_and
168#undef _sig_andn
169
170#define _SIG_SET_OP(name, op) \
171static inline void name(sigset_t *set) \
172{ \
173 switch (_NSIG_WORDS) { \
174 case 4: set->sig[3] = op(set->sig[3]); \
175 set->sig[2] = op(set->sig[2]); \
176 fallthrough; \
177 case 2: set->sig[1] = op(set->sig[1]); \
178 fallthrough; \
179 case 1: set->sig[0] = op(set->sig[0]); \
180 break; \
181 default: \
182 BUILD_BUG(); \
183 } \
184}
185
186#define _sig_not(x) (~(x))
187_SIG_SET_OP(signotset, _sig_not)
188
189#undef _SIG_SET_OP
190#undef _sig_not
191
192static inline void sigemptyset(sigset_t *set)
193{
194 switch (_NSIG_WORDS) {
195 default:
196 memset(s: set, c: 0, n: sizeof(sigset_t));
197 break;
198 case 2: set->sig[1] = 0;
199 fallthrough;
200 case 1: set->sig[0] = 0;
201 break;
202 }
203}
204
205static inline void sigfillset(sigset_t *set)
206{
207 switch (_NSIG_WORDS) {
208 default:
209 memset(s: set, c: -1, n: sizeof(sigset_t));
210 break;
211 case 2: set->sig[1] = -1;
212 fallthrough;
213 case 1: set->sig[0] = -1;
214 break;
215 }
216}
217
218/* Some extensions for manipulating the low 32 signals in particular. */
219
220static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
221{
222 set->sig[0] |= mask;
223}
224
225static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
226{
227 set->sig[0] &= ~mask;
228}
229
230static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
231{
232 return (set->sig[0] & mask) != 0;
233}
234
235static inline void siginitset(sigset_t *set, unsigned long mask)
236{
237 set->sig[0] = mask;
238 switch (_NSIG_WORDS) {
239 default:
240 memset(s: &set->sig[1], c: 0, n: sizeof(long)*(_NSIG_WORDS-1));
241 break;
242 case 2: set->sig[1] = 0;
243 break;
244 case 1: ;
245 }
246}
247
248static inline void siginitsetinv(sigset_t *set, unsigned long mask)
249{
250 set->sig[0] = ~mask;
251 switch (_NSIG_WORDS) {
252 default:
253 memset(s: &set->sig[1], c: -1, n: sizeof(long)*(_NSIG_WORDS-1));
254 break;
255 case 2: set->sig[1] = -1;
256 break;
257 case 1: ;
258 }
259}
260
261#endif /* __HAVE_ARCH_SIG_SETOPS */
262
263static inline void init_sigpending(struct sigpending *sig)
264{
265 sigemptyset(set: &sig->signal);
266 INIT_LIST_HEAD(list: &sig->list);
267}
268
269extern void flush_sigqueue(struct sigpending *queue);
270
271/* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
272static inline int valid_signal(unsigned long sig)
273{
274 return sig <= _NSIG ? 1 : 0;
275}
276
277struct timespec;
278struct pt_regs;
279enum pid_type;
280
281extern int next_signal(struct sigpending *pending, sigset_t *mask);
282extern int do_send_sig_info(int sig, struct kernel_siginfo *info,
283 struct task_struct *p, enum pid_type type);
284extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
285 struct task_struct *p, enum pid_type type);
286extern int send_signal_locked(int sig, struct kernel_siginfo *info,
287 struct task_struct *p, enum pid_type type);
288extern int sigprocmask(int, sigset_t *, sigset_t *);
289extern void set_current_blocked(sigset_t *);
290extern void __set_current_blocked(const sigset_t *);
291extern int show_unhandled_signals;
292
293extern bool get_signal(struct ksignal *ksig);
294extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
295extern void exit_signals(struct task_struct *tsk);
296extern void kernel_sigaction(int, __sighandler_t);
297
298#define SIG_KTHREAD ((__force __sighandler_t)2)
299#define SIG_KTHREAD_KERNEL ((__force __sighandler_t)3)
300
301static inline void allow_signal(int sig)
302{
303 /*
304 * Kernel threads handle their own signals. Let the signal code
305 * know it'll be handled, so that they don't get converted to
306 * SIGKILL or just silently dropped.
307 */
308 kernel_sigaction(sig, SIG_KTHREAD);
309}
310
311static inline void allow_kernel_signal(int sig)
312{
313 /*
314 * Kernel threads handle their own signals. Let the signal code
315 * know signals sent by the kernel will be handled, so that they
316 * don't get silently dropped.
317 */
318 kernel_sigaction(sig, SIG_KTHREAD_KERNEL);
319}
320
321static inline void disallow_signal(int sig)
322{
323 kernel_sigaction(sig, SIG_IGN);
324}
325
326extern struct kmem_cache *sighand_cachep;
327
328extern bool unhandled_signal(struct task_struct *tsk, int sig);
329
330/*
331 * In POSIX a signal is sent either to a specific thread (Linux task)
332 * or to the process as a whole (Linux thread group). How the signal
333 * is sent determines whether it's to one thread or the whole group,
334 * which determines which signal mask(s) are involved in blocking it
335 * from being delivered until later. When the signal is delivered,
336 * either it's caught or ignored by a user handler or it has a default
337 * effect that applies to the whole thread group (POSIX process).
338 *
339 * The possible effects an unblocked signal set to SIG_DFL can have are:
340 * ignore - Nothing Happens
341 * terminate - kill the process, i.e. all threads in the group,
342 * similar to exit_group. The group leader (only) reports
343 * WIFSIGNALED status to its parent.
344 * coredump - write a core dump file describing all threads using
345 * the same mm and then kill all those threads
346 * stop - stop all the threads in the group, i.e. TASK_STOPPED state
347 *
348 * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
349 * Other signals when not blocked and set to SIG_DFL behaves as follows.
350 * The job control signals also have other special effects.
351 *
352 * +--------------------+------------------+
353 * | POSIX signal | default action |
354 * +--------------------+------------------+
355 * | SIGHUP | terminate |
356 * | SIGINT | terminate |
357 * | SIGQUIT | coredump |
358 * | SIGILL | coredump |
359 * | SIGTRAP | coredump |
360 * | SIGABRT/SIGIOT | coredump |
361 * | SIGBUS | coredump |
362 * | SIGFPE | coredump |
363 * | SIGKILL | terminate(+) |
364 * | SIGUSR1 | terminate |
365 * | SIGSEGV | coredump |
366 * | SIGUSR2 | terminate |
367 * | SIGPIPE | terminate |
368 * | SIGALRM | terminate |
369 * | SIGTERM | terminate |
370 * | SIGCHLD | ignore |
371 * | SIGCONT | ignore(*) |
372 * | SIGSTOP | stop(*)(+) |
373 * | SIGTSTP | stop(*) |
374 * | SIGTTIN | stop(*) |
375 * | SIGTTOU | stop(*) |
376 * | SIGURG | ignore |
377 * | SIGXCPU | coredump |
378 * | SIGXFSZ | coredump |
379 * | SIGVTALRM | terminate |
380 * | SIGPROF | terminate |
381 * | SIGPOLL/SIGIO | terminate |
382 * | SIGSYS/SIGUNUSED | coredump |
383 * | SIGSTKFLT | terminate |
384 * | SIGWINCH | ignore |
385 * | SIGPWR | terminate |
386 * | SIGRTMIN-SIGRTMAX | terminate |
387 * +--------------------+------------------+
388 * | non-POSIX signal | default action |
389 * +--------------------+------------------+
390 * | SIGEMT | coredump |
391 * +--------------------+------------------+
392 *
393 * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
394 * (*) Special job control effects:
395 * When SIGCONT is sent, it resumes the process (all threads in the group)
396 * from TASK_STOPPED state and also clears any pending/queued stop signals
397 * (any of those marked with "stop(*)"). This happens regardless of blocking,
398 * catching, or ignoring SIGCONT. When any stop signal is sent, it clears
399 * any pending/queued SIGCONT signals; this happens regardless of blocking,
400 * catching, or ignored the stop signal, though (except for SIGSTOP) the
401 * default action of stopping the process may happen later or never.
402 */
403
404#ifdef SIGEMT
405#define SIGEMT_MASK rt_sigmask(SIGEMT)
406#else
407#define SIGEMT_MASK 0
408#endif
409
410#if SIGRTMIN > BITS_PER_LONG
411#define rt_sigmask(sig) (1ULL << ((sig)-1))
412#else
413#define rt_sigmask(sig) sigmask(sig)
414#endif
415
416#define siginmask(sig, mask) \
417 ((sig) > 0 && (sig) < SIGRTMIN && (rt_sigmask(sig) & (mask)))
418
419#define SIG_KERNEL_ONLY_MASK (\
420 rt_sigmask(SIGKILL) | rt_sigmask(SIGSTOP))
421
422#define SIG_KERNEL_STOP_MASK (\
423 rt_sigmask(SIGSTOP) | rt_sigmask(SIGTSTP) | \
424 rt_sigmask(SIGTTIN) | rt_sigmask(SIGTTOU) )
425
426#define SIG_KERNEL_COREDUMP_MASK (\
427 rt_sigmask(SIGQUIT) | rt_sigmask(SIGILL) | \
428 rt_sigmask(SIGTRAP) | rt_sigmask(SIGABRT) | \
429 rt_sigmask(SIGFPE) | rt_sigmask(SIGSEGV) | \
430 rt_sigmask(SIGBUS) | rt_sigmask(SIGSYS) | \
431 rt_sigmask(SIGXCPU) | rt_sigmask(SIGXFSZ) | \
432 SIGEMT_MASK )
433
434#define SIG_KERNEL_IGNORE_MASK (\
435 rt_sigmask(SIGCONT) | rt_sigmask(SIGCHLD) | \
436 rt_sigmask(SIGWINCH) | rt_sigmask(SIGURG) )
437
438#define SIG_SPECIFIC_SICODES_MASK (\
439 rt_sigmask(SIGILL) | rt_sigmask(SIGFPE) | \
440 rt_sigmask(SIGSEGV) | rt_sigmask(SIGBUS) | \
441 rt_sigmask(SIGTRAP) | rt_sigmask(SIGCHLD) | \
442 rt_sigmask(SIGPOLL) | rt_sigmask(SIGSYS) | \
443 SIGEMT_MASK )
444
445#define sig_kernel_only(sig) siginmask(sig, SIG_KERNEL_ONLY_MASK)
446#define sig_kernel_coredump(sig) siginmask(sig, SIG_KERNEL_COREDUMP_MASK)
447#define sig_kernel_ignore(sig) siginmask(sig, SIG_KERNEL_IGNORE_MASK)
448#define sig_kernel_stop(sig) siginmask(sig, SIG_KERNEL_STOP_MASK)
449#define sig_specific_sicodes(sig) siginmask(sig, SIG_SPECIFIC_SICODES_MASK)
450
451#define sig_fatal(t, signr) \
452 (!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
453 (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
454
455void signals_init(void);
456
457int restore_altstack(const stack_t __user *);
458int __save_altstack(stack_t __user *, unsigned long);
459
460#define unsafe_save_altstack(uss, sp, label) do { \
461 stack_t __user *__uss = uss; \
462 struct task_struct *t = current; \
463 unsafe_put_user((void __user *)t->sas_ss_sp, &__uss->ss_sp, label); \
464 unsafe_put_user(t->sas_ss_flags, &__uss->ss_flags, label); \
465 unsafe_put_user(t->sas_ss_size, &__uss->ss_size, label); \
466} while (0);
467
468#ifdef CONFIG_DYNAMIC_SIGFRAME
469bool sigaltstack_size_valid(size_t ss_size);
470#else
471static inline bool sigaltstack_size_valid(size_t size) { return true; }
472#endif /* !CONFIG_DYNAMIC_SIGFRAME */
473
474#ifdef CONFIG_PROC_FS
475struct seq_file;
476extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
477#endif
478
479#ifndef arch_untagged_si_addr
480/*
481 * Given a fault address and a signal and si_code which correspond to the
482 * _sigfault union member, returns the address that must appear in si_addr if
483 * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags.
484 */
485static inline void __user *arch_untagged_si_addr(void __user *addr,
486 unsigned long sig,
487 unsigned long si_code)
488{
489 return addr;
490}
491#endif
492
493#endif /* _LINUX_SIGNAL_H */
494