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 #include <linux/string.h>
130
131 #define _SIG_SET_BINOP(name, op) \
132 static 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))
_SIG_SET_BINOP(sigorsets,_sig_or)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) \
171 static 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
192 static inline void sigemptyset(sigset_t *set)
193 {
194 switch (_NSIG_WORDS) {
195 default:
196 memset(set, 0, 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
sigfillset(sigset_t * set)205 static inline void sigfillset(sigset_t *set)
206 {
207 switch (_NSIG_WORDS) {
208 default:
209 memset(set, -1, 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
sigaddsetmask(sigset_t * set,unsigned long mask)220 static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
221 {
222 set->sig[0] |= mask;
223 }
224
sigdelsetmask(sigset_t * set,unsigned long mask)225 static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
226 {
227 set->sig[0] &= ~mask;
228 }
229
sigtestsetmask(sigset_t * set,unsigned long mask)230 static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
231 {
232 return (set->sig[0] & mask) != 0;
233 }
234
siginitset(sigset_t * set,unsigned long mask)235 static inline void siginitset(sigset_t *set, unsigned long mask)
236 {
237 set->sig[0] = mask;
238 switch (_NSIG_WORDS) {
239 default:
240 memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
241 break;
242 case 2: set->sig[1] = 0;
243 break;
244 case 1: ;
245 }
246 }
247
siginitsetinv(sigset_t * set,unsigned long mask)248 static inline void siginitsetinv(sigset_t *set, unsigned long mask)
249 {
250 set->sig[0] = ~mask;
251 switch (_NSIG_WORDS) {
252 default:
253 memset(&set->sig[1], -1, 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
init_sigpending(struct sigpending * sig)263 static inline void init_sigpending(struct sigpending *sig)
264 {
265 sigemptyset(&sig->signal);
266 INIT_LIST_HEAD(&sig->list);
267 }
268
269 extern void flush_sigqueue(struct sigpending *queue);
270
271 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
valid_signal(unsigned long sig)272 static inline int valid_signal(unsigned long sig)
273 {
274 return sig <= _NSIG ? 1 : 0;
275 }
276
277 struct timespec;
278 struct pt_regs;
279 enum pid_type;
280
281 extern int next_signal(struct sigpending *pending, sigset_t *mask);
282 extern int do_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 sig, struct kernel_siginfo *info,
285 struct task_struct *p, enum pid_type type);
286 extern int __group_send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
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_PROC_FS
468 struct seq_file;
469 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
470 #endif
471
472 #ifndef arch_untagged_si_addr
473 /*
474 * Given a fault address and a signal and si_code which correspond to the
475 * _sigfault union member, returns the address that must appear in si_addr if
476 * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags.
477 */
arch_untagged_si_addr(void __user * addr,unsigned long sig,unsigned long si_code)478 static inline void __user *arch_untagged_si_addr(void __user *addr,
479 unsigned long sig,
480 unsigned long si_code)
481 {
482 return addr;
483 }
484 #endif
485
486 #endif /* _LINUX_SIGNAL_H */
487
