sigchain.c

   1 #include "cache.h"
   2 #include "sigchain.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
  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
  19 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
  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
  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 }