1 // SPDX-License-Identifier: GPL-2.0
2 #include <signal.h>
3 #include "subcmd-util.h"
4 #include "sigchain.h"
5
6 #define SIGCHAIN_MAX_SIGNALS 32
7
8 struct sigchain_signal {
9 sigchain_fun *old;
10 int n;
11 int alloc;
12 };
13 static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];
14
check_signum(int sig)15 static void check_signum(int sig)
16 {
17 if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)
18 die("BUG: signal out of range: %d", sig);
19 }
20
sigchain_push(int sig,sigchain_fun f)21 static int sigchain_push(int sig, sigchain_fun f)
22 {
23 struct sigchain_signal *s = signals + sig;
24 check_signum(sig);
25
26 ALLOC_GROW(s->old, s->n + 1, s->alloc);
27 s->old[s->n] = signal(sig, f);
28 if (s->old[s->n] == SIG_ERR)
29 return -1;
30 s->n++;
31 return 0;
32 }
33
sigchain_pop(int sig)34 int sigchain_pop(int sig)
35 {
36 struct sigchain_signal *s = signals + sig;
37 check_signum(sig);
38 if (s->n < 1)
39 return 0;
40
41 if (signal(sig, s->old[s->n - 1]) == SIG_ERR)
42 return -1;
43 s->n--;
44 return 0;
45 }
46
sigchain_push_common(sigchain_fun f)47 void sigchain_push_common(sigchain_fun f)
48 {
49 sigchain_push(SIGINT, f);
50 sigchain_push(SIGHUP, f);
51 sigchain_push(SIGTERM, f);
52 sigchain_push(SIGQUIT, f);
53 sigchain_push(SIGPIPE, f);
54 }
55