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/list.h>
7#include <linux/signal_types.h>
8#include <linux/string.h>
9
10struct task_struct;
11
12/* for sysctl */
13extern int print_fatal_signals;
14
15static inline void copy_siginfo(kernel_siginfo_t *to,
16				const kernel_siginfo_t *from)
17{
18	memcpy(to, from, sizeof(*to));
19}
20
21static inline void clear_siginfo(kernel_siginfo_t *info)
22{
23	memset(info, 0, sizeof(*info));
24}
25
26#define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))
27
28static inline void copy_siginfo_to_external(siginfo_t *to,
29					    const kernel_siginfo_t *from)
30{
31	memcpy(to, from, sizeof(*from));
32	memset(((char *)to) + sizeof(struct kernel_siginfo), 0,
33		SI_EXPANSION_SIZE);
34}
35
36int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
37int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
38
39enum siginfo_layout {
40	SIL_KILL,
41	SIL_TIMER,
42	SIL_POLL,
43	SIL_FAULT,
44	SIL_FAULT_TRAPNO,
45	SIL_FAULT_MCEERR,
46	SIL_FAULT_BNDERR,
47	SIL_FAULT_PKUERR,
48	SIL_FAULT_PERF_EVENT,
49	SIL_CHLD,
50	SIL_RT,
51	SIL_SYS,
52};
53
54enum siginfo_layout siginfo_layout(unsigned sig, int si_code);
55
56/*
57 * Define some primitives to manipulate sigset_t.
58 */
59
60#ifndef __HAVE_ARCH_SIG_BITOPS
61#include <linux/bitops.h>
62
63/* We don't use <linux/bitops.h> for these because there is no need to
64   be atomic.  */
65static inline void sigaddset(sigset_t *set, int _sig)
66{
67	unsigned long sig = _sig - 1;
68	if (_NSIG_WORDS == 1)
69		set->sig[0] |= 1UL << sig;
70	else
71		set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
72}
73
74static inline void sigdelset(sigset_t *set, int _sig)
75{
76	unsigned long sig = _sig - 1;
77	if (_NSIG_WORDS == 1)
78		set->sig[0] &= ~(1UL << sig);
79	else
80		set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
81}
82
83static inline int sigismember(sigset_t *set, int _sig)
84{
85	unsigned long sig = _sig - 1;
86	if (_NSIG_WORDS == 1)
87		return 1 & (set->sig[0] >> sig);
88	else
89		return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
90}
91
92#endif /* __HAVE_ARCH_SIG_BITOPS */
93
94static inline int sigisemptyset(sigset_t *set)
95{
96	switch (_NSIG_WORDS) {
97	case 4:
98		return (set->sig[3] | set->sig[2] |
99			set->sig[1] | set->sig[0]) == 0;
100	case 2:
101		return (set->sig[1] | set->sig[0]) == 0;
102	case 1:
103		return set->sig[0] == 0;
104	default:
105		BUILD_BUG();
106		return 0;
107	}
108}
109
110static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2)
111{
112	switch (_NSIG_WORDS) {
113	case 4:
114		return	(set1->sig[3] == set2->sig[3]) &&
115			(set1->sig[2] == set2->sig[2]) &&
116			(set1->sig[1] == set2->sig[1]) &&
117			(set1->sig[0] == set2->sig[0]);
118	case 2:
119		return	(set1->sig[1] == set2->sig[1]) &&
120			(set1->sig[0] == set2->sig[0]);
121	case 1:
122		return	set1->sig[0] == set2->sig[0];
123	}
124	return 0;
125}
126
127#define sigmask(sig)	(1UL << ((sig) - 1))
128
129#ifndef __HAVE_ARCH_SIG_SETOPS
130
131#define _SIG_SET_BINOP(name, op)					\
132static 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))
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)						\
171static 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
192static 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
205static 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
220static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
221{
222	set->sig[0] |= mask;
223}
224
225static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
226{
227	set->sig[0] &= ~mask;
228}
229
230static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
231{
232	return (set->sig[0] & mask) != 0;
233}
234
235static 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
248static 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
263static inline void init_sigpending(struct sigpending *sig)
264{
265	sigemptyset(&sig->signal);
266	INIT_LIST_HEAD(&sig->list);
267}
268
269extern void flush_sigqueue(struct sigpending *queue);
270
271/* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
272static inline int valid_signal(unsigned long sig)
273{
274	return sig <= _NSIG ? 1 : 0;
275}
276
277struct timespec;
278struct pt_regs;
279enum pid_type;
280
281extern int next_signal(struct sigpending *pending, sigset_t *mask);
282extern int do_send_sig_info(int sig, struct kernel_siginfo *info,
283				struct task_struct *p, enum pid_type type);
284extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
285			       struct task_struct *p, enum pid_type type);
286extern int send_signal_locked(int sig, struct kernel_siginfo *info,
287			      struct task_struct *p, enum pid_type type);
288extern int sigprocmask(int, sigset_t *, sigset_t *);
289extern void set_current_blocked(sigset_t *);
290extern void __set_current_blocked(const sigset_t *);
291extern int show_unhandled_signals;
292
293extern bool get_signal(struct ksignal *ksig);
294extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
295extern void exit_signals(struct task_struct *tsk);
296extern void kernel_sigaction(int, __sighandler_t);
297
298#define SIG_KTHREAD ((__force __sighandler_t)2)
299#define SIG_KTHREAD_KERNEL ((__force __sighandler_t)3)
300
301static inline void allow_signal(int sig)
302{
303	/*
304	 * Kernel threads handle their own signals. Let the signal code
305	 * know it'll be handled, so that they don't get converted to
306	 * SIGKILL or just silently dropped.
307	 */
308	kernel_sigaction(sig, SIG_KTHREAD);
309}
310
311static inline void allow_kernel_signal(int sig)
312{
313	/*
314	 * Kernel threads handle their own signals. Let the signal code
315	 * know signals sent by the kernel will be handled, so that they
316	 * don't get silently dropped.
317	 */
318	kernel_sigaction(sig, SIG_KTHREAD_KERNEL);
319}
320
321static inline void disallow_signal(int sig)
322{
323	kernel_sigaction(sig, SIG_IGN);
324}
325
326extern struct kmem_cache *sighand_cachep;
327
328extern bool unhandled_signal(struct task_struct *tsk, int sig);
329
330/*
331 * In POSIX a signal is sent either to a specific thread (Linux task)
332 * or to the process as a whole (Linux thread group).  How the signal
333 * is sent determines whether it's to one thread or the whole group,
334 * which determines which signal mask(s) are involved in blocking it
335 * from being delivered until later.  When the signal is delivered,
336 * either it's caught or ignored by a user handler or it has a default
337 * effect that applies to the whole thread group (POSIX process).
338 *
339 * The possible effects an unblocked signal set to SIG_DFL can have are:
340 *   ignore	- Nothing Happens
341 *   terminate	- kill the process, i.e. all threads in the group,
342 * 		  similar to exit_group.  The group leader (only) reports
343 *		  WIFSIGNALED status to its parent.
344 *   coredump	- write a core dump file describing all threads using
345 *		  the same mm and then kill all those threads
346 *   stop 	- stop all the threads in the group, i.e. TASK_STOPPED state
347 *
348 * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
349 * Other signals when not blocked and set to SIG_DFL behaves as follows.
350 * The job control signals also have other special effects.
351 *
352 *	+--------------------+------------------+
353 *	|  POSIX signal      |  default action  |
354 *	+--------------------+------------------+
355 *	|  SIGHUP            |  terminate	|
356 *	|  SIGINT            |	terminate	|
357 *	|  SIGQUIT           |	coredump 	|
358 *	|  SIGILL            |	coredump 	|
359 *	|  SIGTRAP           |	coredump 	|
360 *	|  SIGABRT/SIGIOT    |	coredump 	|
361 *	|  SIGBUS            |	coredump 	|
362 *	|  SIGFPE            |	coredump 	|
363 *	|  SIGKILL           |	terminate(+)	|
364 *	|  SIGUSR1           |	terminate	|
365 *	|  SIGSEGV           |	coredump 	|
366 *	|  SIGUSR2           |	terminate	|
367 *	|  SIGPIPE           |	terminate	|
368 *	|  SIGALRM           |	terminate	|
369 *	|  SIGTERM           |	terminate	|
370 *	|  SIGCHLD           |	ignore   	|
371 *	|  SIGCONT           |	ignore(*)	|
372 *	|  SIGSTOP           |	stop(*)(+)  	|
373 *	|  SIGTSTP           |	stop(*)  	|
374 *	|  SIGTTIN           |	stop(*)  	|
375 *	|  SIGTTOU           |	stop(*)  	|
376 *	|  SIGURG            |	ignore   	|
377 *	|  SIGXCPU           |	coredump 	|
378 *	|  SIGXFSZ           |	coredump 	|
379 *	|  SIGVTALRM         |	terminate	|
380 *	|  SIGPROF           |	terminate	|
381 *	|  SIGPOLL/SIGIO     |	terminate	|
382 *	|  SIGSYS/SIGUNUSED  |	coredump 	|
383 *	|  SIGSTKFLT         |	terminate	|
384 *	|  SIGWINCH          |	ignore   	|
385 *	|  SIGPWR            |	terminate	|
386 *	|  SIGRTMIN-SIGRTMAX |	terminate       |
387 *	+--------------------+------------------+
388 *	|  non-POSIX signal  |  default action  |
389 *	+--------------------+------------------+
390 *	|  SIGEMT            |  coredump	|
391 *	+--------------------+------------------+
392 *
393 * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
394 * (*) Special job control effects:
395 * When SIGCONT is sent, it resumes the process (all threads in the group)
396 * from TASK_STOPPED state and also clears any pending/queued stop signals
397 * (any of those marked with "stop(*)").  This happens regardless of blocking,
398 * catching, or ignoring SIGCONT.  When any stop signal is sent, it clears
399 * any pending/queued SIGCONT signals; this happens regardless of blocking,
400 * catching, or ignored the stop signal, though (except for SIGSTOP) the
401 * default action of stopping the process may happen later or never.
402 */
403
404#ifdef SIGEMT
405#define SIGEMT_MASK	rt_sigmask(SIGEMT)
406#else
407#define SIGEMT_MASK	0
408#endif
409
410#if SIGRTMIN > BITS_PER_LONG
411#define rt_sigmask(sig)	(1ULL << ((sig)-1))
412#else
413#define rt_sigmask(sig)	sigmask(sig)
414#endif
415
416#define siginmask(sig, mask) \
417	((sig) > 0 && (sig) < SIGRTMIN && (rt_sigmask(sig) & (mask)))
418
419#define SIG_KERNEL_ONLY_MASK (\
420	rt_sigmask(SIGKILL)   |  rt_sigmask(SIGSTOP))
421
422#define SIG_KERNEL_STOP_MASK (\
423	rt_sigmask(SIGSTOP)   |  rt_sigmask(SIGTSTP)   | \
424	rt_sigmask(SIGTTIN)   |  rt_sigmask(SIGTTOU)   )
425
426#define SIG_KERNEL_COREDUMP_MASK (\
427        rt_sigmask(SIGQUIT)   |  rt_sigmask(SIGILL)    | \
428	rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGABRT)   | \
429        rt_sigmask(SIGFPE)    |  rt_sigmask(SIGSEGV)   | \
430	rt_sigmask(SIGBUS)    |  rt_sigmask(SIGSYS)    | \
431        rt_sigmask(SIGXCPU)   |  rt_sigmask(SIGXFSZ)   | \
432	SIGEMT_MASK				       )
433
434#define SIG_KERNEL_IGNORE_MASK (\
435        rt_sigmask(SIGCONT)   |  rt_sigmask(SIGCHLD)   | \
436	rt_sigmask(SIGWINCH)  |  rt_sigmask(SIGURG)    )
437
438#define SIG_SPECIFIC_SICODES_MASK (\
439	rt_sigmask(SIGILL)    |  rt_sigmask(SIGFPE)    | \
440	rt_sigmask(SIGSEGV)   |  rt_sigmask(SIGBUS)    | \
441	rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGCHLD)   | \
442	rt_sigmask(SIGPOLL)   |  rt_sigmask(SIGSYS)    | \
443	SIGEMT_MASK                                    )
444
445#define sig_kernel_only(sig)		siginmask(sig, SIG_KERNEL_ONLY_MASK)
446#define sig_kernel_coredump(sig)	siginmask(sig, SIG_KERNEL_COREDUMP_MASK)
447#define sig_kernel_ignore(sig)		siginmask(sig, SIG_KERNEL_IGNORE_MASK)
448#define sig_kernel_stop(sig)		siginmask(sig, SIG_KERNEL_STOP_MASK)
449#define sig_specific_sicodes(sig)	siginmask(sig, SIG_SPECIFIC_SICODES_MASK)
450
451#define sig_fatal(t, signr) \
452	(!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
453	 (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
454
455void signals_init(void);
456
457int restore_altstack(const stack_t __user *);
458int __save_altstack(stack_t __user *, unsigned long);
459
460#define unsafe_save_altstack(uss, sp, label) do { \
461	stack_t __user *__uss = uss; \
462	struct task_struct *t = current; \
463	unsafe_put_user((void __user *)t->sas_ss_sp, &__uss->ss_sp, label); \
464	unsafe_put_user(t->sas_ss_flags, &__uss->ss_flags, label); \
465	unsafe_put_user(t->sas_ss_size, &__uss->ss_size, label); \
466} while (0);
467
468#ifdef CONFIG_DYNAMIC_SIGFRAME
469bool sigaltstack_size_valid(size_t ss_size);
470#else
471static inline bool sigaltstack_size_valid(size_t size) { return true; }
472#endif /* !CONFIG_DYNAMIC_SIGFRAME */
473
474#ifdef CONFIG_PROC_FS
475struct seq_file;
476extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
477#endif
478
479#ifndef arch_untagged_si_addr
480/*
481 * Given a fault address and a signal and si_code which correspond to the
482 * _sigfault union member, returns the address that must appear in si_addr if
483 * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags.
484 */
485static inline void __user *arch_untagged_si_addr(void __user *addr,
486						 unsigned long sig,
487						 unsigned long si_code)
488{
489	return addr;
490}
491#endif
492
493#endif /* _LINUX_SIGNAL_H */
494