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