summaryrefslogtreecommitdiffstats
path: root/src/sighook.h
blob: 3bece213672b629de42da3843ef97f7266cd76f5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD

/**
 * Signal hooks.
 */

#ifndef BFS_SIGHOOK_H
#define BFS_SIGHOOK_H

#include <signal.h>

/**
 * A dynamic signal hook.
 */
struct sighook;

/**
 * Signal hook flags.
 */
enum sigflags {
	/** Suppress the default action for this signal. */
	SH_CONTINUE = 1 << 0,
};

/**
 * A signal hook callback.  Hooks are executed from a signal handler, so must
 * only call async-signal-safe functions.
 *
 * @sig
 *         The signal number.
 * @info
 *         Additional information about the signal.
 * @arg
 *         An arbitrary pointer passed to the hook.
 */
typedef void sighook_fn(int sig, siginfo_t *info, void *arg);

/**
 * Install a hook for a signal.
 *
 * @sig
 *         The signal to hook.
 * @fn
 *         The function to call.
 * @arg
 *         An argument passed to the function.
 * @flags
 *         Flags for the new hook.
 * @return
 *         The installed hook, or NULL on failure.
 */
struct sighook *sighook(int sig, sighook_fn *fn, void *arg, enum sigflags flags);

/**
 * On a best-effort basis, invoke the given hook just before the program is
 * abnormally terminated by a signal.
 *
 * @fn
 *         The function to call.
 * @arg
 *         An argument passed to the function.
 * @return
 *         The installed hook, or NULL on failure.
 */
struct sighook *atsigexit(sighook_fn *fn, void *arg);

/**
 * Remove a signal hook.
 */
void sigunhook(struct sighook *hook);

#endif // BFS_SIGHOOK_H