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_PERF_EVENT,
47 SIL_CHLD,
48 SIL_RT,
49 SIL_SYS,
50 };
51
52 enum siginfo_layout siginfo_layout(unsigned sig, int si_code);
53
54 /*
55 * Define some primitives to manipulate sigset_t.
56 */
57
58 #ifndef __HAVE_ARCH_SIG_BITOPS
59 #include <linux/bitops.h>
60
61 /* We don't use <linux/bitops.h> for these because there is no need to
62 be atomic. */
sigaddset(sigset_t * set,int _sig)63 static inline void sigaddset(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
sigdelset(sigset_t * set,int _sig)72 static inline void sigdelset(sigset_t *set, int _sig)
73 {
74 unsigned long sig = _sig - 1;
75 if (_NSIG_WORDS == 1)
76 set->sig[0] &= ~(1UL << sig);
77 else
78 set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
79 }
80
sigismember(sigset_t * set,int _sig)81 static inline int sigismember(sigset_t *set, int _sig)
82 {
83 unsigned long sig = _sig - 1;
84 if (_NSIG_WORDS == 1)
85 return 1 & (set->sig[0] >> sig);
86 else
87 return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
88 }
89
90 #endif /* __HAVE_ARCH_SIG_BITOPS */
91
sigisemptyset(sigset_t * set)92 static inline int sigisemptyset(sigset_t *set)
93 {
94 switch (_NSIG_WORDS) {
95 case 4:
96 return (set->sig[3] | set->sig[2] |
97 set->sig[1] | set->sig[0]) == 0;
98 case 2:
99 return (set->sig[1] | set->sig[0]) == 0;
100 case 1:
101 return set->sig[0] == 0;
102 default:
103 BUILD_BUG();
104 return 0;
105 }
106 }
107
sigequalsets(const sigset_t * set1,const sigset_t * set2)108 static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2)
109 {
110 switch (_NSIG_WORDS) {
111 case 4:
112 return (set1->sig[3] == set2->sig[3]) &&
113 (set1->sig[2] == set2->sig[2]) &&
114 (set1->sig[1] == set2->sig[1]) &&
115 (set1->sig[0] == set2->sig[0]);
116 case 2:
117 return (set1->sig[1] == set2->sig[1]) &&
118 (set1->sig[0] == set2->sig[0]);
119 case 1:
120 return set1->sig[0] == set2->sig[0];
121 }
122 return 0;
123 }
124
125 #define sigmask(sig) (1UL << ((sig) - 1))
126
127 #ifndef __HAVE_ARCH_SIG_SETOPS
128 #include <linux/string.h>
129
130 #define _SIG_SET_BINOP(name, op) \
131 static 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))
_SIG_SET_BINOP(sigorsets,_sig_or)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) \
170 static 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
191 static 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
sigfillset(sigset_t * set)204 static 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
sigaddsetmask(sigset_t * set,unsigned long mask)219 static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
220 {
221 set->sig[0] |= mask;
222 }
223
sigdelsetmask(sigset_t * set,unsigned long mask)224 static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
225 {
226 set->sig[0] &= ~mask;
227 }
228
sigtestsetmask(sigset_t * set,unsigned long mask)229 static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
230 {
231 return (set->sig[0] & mask) != 0;
232 }
233
siginitset(sigset_t * set,unsigned long mask)234 static 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
siginitsetinv(sigset_t * set,unsigned long mask)247 static 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
init_sigpending(struct sigpending * sig)262 static inline void init_sigpending(struct sigpending *sig)
263 {
264 sigemptyset(&sig->signal);
265 INIT_LIST_HEAD(&sig->list);
266 }
267
268 extern void flush_sigqueue(struct sigpending *queue);
269 extern void exit_task_sigqueue_cache(struct task_struct *tsk);
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 if (t->sas_ss_flags & SS_AUTODISARM) \
466 sas_ss_reset(t); \
467 } while (0);
468
469 #ifdef CONFIG_PROC_FS
470 struct seq_file;
471 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
472 #endif
473
474 #ifndef arch_untagged_si_addr
475 /*
476 * Given a fault address and a signal and si_code which correspond to the
477 * _sigfault union member, returns the address that must appear in si_addr if
478 * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags.
479 */
arch_untagged_si_addr(void __user * addr,unsigned long sig,unsigned long si_code)480 static inline void __user *arch_untagged_si_addr(void __user *addr,
481 unsigned long sig,
482 unsigned long si_code)
483 {
484 return addr;
485 }
486 #endif
487
488 #endif /* _LINUX_SIGNAL_H */
489