1 #include "sigchain.h"
2 #include "cache.h"
3
4 #define SIGCHAIN_MAX_SIGNALS 32
5
6 struct sigchain_signal {
7 sigchain_fun *old;
8 int n;
9 int alloc;
10 };
11 static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];
12
check_signum(int sig)13 static 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
sigchain_push(int sig,sigchain_fun f)19 static 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
sigchain_pop(int sig)32 int 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
sigchain_push_common(sigchain_fun f)45 void 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