sigchain.c revision e6817ec1d8ab31fc7b01906e305f848542df6413 
1#include "sigchain.h"
2#include "cache.h"
3
4#define SIGCHAIN_MAX_SIGNALS 32
5
6struct sigchain_signal {
7	sigchain_fun *old;
8	int n;
9	int alloc;
10};
11static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];
12
13static void check_signum(int sig)
14{
15	if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)
16		die("BUG: signal out of range: %d", sig);
17}
18
19static int sigchain_push(int sig, sigchain_fun f)
20{
21	struct sigchain_signal *s = signals + sig;
22	check_signum(sig);
23
24	ALLOC_GROW(s->old, s->n + 1, s->alloc);
25	s->old[s->n] = signal(sig, f);
26	if (s->old[s->n] == SIG_ERR)
27		return -1;
28	s->n++;
29	return 0;
30}
31
32int sigchain_pop(int sig)
33{
34	struct sigchain_signal *s = signals + sig;
35	check_signum(sig);
36	if (s->n < 1)
37		return 0;
38
39	if (signal(sig, s->old[s->n - 1]) == SIG_ERR)
40		return -1;
41	s->n--;
42	return 0;
43}
44
45void sigchain_push_common(sigchain_fun f)
46{
47	sigchain_push(SIGINT, f);
48	sigchain_push(SIGHUP, f);
49	sigchain_push(SIGTERM, f);
50	sigchain_push(SIGQUIT, f);
51	sigchain_push(SIGPIPE, f);
52}
53