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