Line data Source code
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 :
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 :
20 65 : static inline void clear_siginfo(kernel_siginfo_t *info)
21 : {
22 65 : memset(info, 0, sizeof(*info));
23 65 : }
24 :
25 : #define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))
26 :
27 0 : static inline void copy_siginfo_to_external(siginfo_t *to,
28 : const kernel_siginfo_t *from)
29 : {
30 0 : memcpy(to, from, sizeof(*from));
31 0 : memset(((char *)to) + sizeof(struct kernel_siginfo), 0,
32 : SI_EXPANSION_SIZE);
33 0 : }
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. */
64 : static inline void sigaddset(sigset_t *set, int _sig)
65 : {
66 87 : unsigned long sig = _sig - 1;
67 87 : if (_NSIG_WORDS == 1)
68 87 : set->sig[0] |= 1UL << sig;
69 : else
70 : set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
71 : }
72 :
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 :
82 : static inline int sigismember(sigset_t *set, int _sig)
83 : {
84 3027 : unsigned long sig = _sig - 1;
85 3027 : if (_NSIG_WORDS == 1)
86 3027 : 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 :
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 :
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 :
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))
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 48770 : _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 :
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 :
219 : static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
220 : {
221 : set->sig[0] |= mask;
222 : }
223 :
224 : static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
225 : {
226 48770 : set->sig[0] &= ~mask;
227 : }
228 :
229 : static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
230 : {
231 : return (set->sig[0] & mask) != 0;
232 : }
233 :
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 :
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 :
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 :
270 : /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
271 : static inline int valid_signal(unsigned long sig)
272 : {
273 : return sig <= _NSIG ? 1 : 0;
274 : }
275 :
276 : struct timespec;
277 : struct pt_regs;
278 : enum pid_type;
279 :
280 : extern int next_signal(struct sigpending *pending, sigset_t *mask);
281 : extern int do_send_sig_info(int sig, struct kernel_siginfo *info,
282 : struct task_struct *p, enum pid_type type);
283 : extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
284 : struct task_struct *p, enum pid_type type);
285 : extern int send_signal_locked(int sig, struct kernel_siginfo *info,
286 : struct task_struct *p, enum pid_type type);
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 :
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 :
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 :
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_DYNAMIC_SIGFRAME
468 : bool sigaltstack_size_valid(size_t ss_size);
469 : #else
470 : static inline bool sigaltstack_size_valid(size_t size) { return true; }
471 : #endif /* !CONFIG_DYNAMIC_SIGFRAME */
472 :
473 : #ifdef CONFIG_PROC_FS
474 : struct seq_file;
475 : extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
476 : #endif
477 :
478 : #ifndef arch_untagged_si_addr
479 : /*
480 : * Given a fault address and a signal and si_code which correspond to the
481 : * _sigfault union member, returns the address that must appear in si_addr if
482 : * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags.
483 : */
484 : static inline void __user *arch_untagged_si_addr(void __user *addr,
485 : unsigned long sig,
486 : unsigned long si_code)
487 : {
488 : return addr;
489 : }
490 : #endif
491 :
492 : #endif /* _LINUX_SIGNAL_H */
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