diplodocus.org Git - nmh/blob - sbr/signals.c

   1
   2 /*
   3  * signals.c -- general signals interface for nmh
   4  *
   5  * $Id$
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/signals.h>
  10
  11
  12 int
  13 SIGPROCMASK (int how, const sigset_t *set, sigset_t *oset)
  14 {
  15 #ifdef POSIX_SIGNALS
  16     return sigprocmask(how, set, oset);
  17 #else
  18 # ifdef BSD_SIGNALS
  19     switch(how) {
  20     case SIG_BLOCK:
  21         *oset = sigblock(*set);
  22         break;
  23     case SIG_UNBLOCK:
  24         sigfillset(*oset);
  25         *oset = sigsetmask(*oset);
  26         sigsetmask(*oset & ~(*set));
  27         break;
  28     case SIG_SETMASK:
  29         *oset = sigsetmask(*set);
  30         break;
  31     default:
  32         adios(NULL, "unknown flag in SIGPROCMASK");
  33         break;
  34     }
  35     return 0;
  36 # endif
  37 #endif
  38 }
  39
  40
  41 /*
  42  * A version of the function `signal' that uses reliable
  43  * signals, if the machine supports them.  Also, (assuming
  44  * OS support), it restarts interrupted system calls for all
  45  * signals except SIGALRM.
  46  */
  47
  48 SIGNAL_HANDLER
  49 SIGNAL (int sig, SIGNAL_HANDLER func)
  50 {
  51 #ifdef POSIX_SIGNALS
  52     struct sigaction act, oact;
  53
  54     act.sa_handler = func;
  55     sigemptyset(&act.sa_mask);
  56     act.sa_flags = 0;
  57
  58     if (sig == SIGALRM) {
  59 # ifdef SA_INTERRUPT
  60         act.sa_flags |= SA_INTERRUPT;     /* SunOS */
  61 # endif
  62     } else {
  63 # ifdef SA_RESTART
  64         act.sa_flags |= SA_RESTART;       /* SVR4, BSD4.4 */
  65 # endif
  66     }
  67     if (sigaction(sig, &act, &oact) < 0)
  68         return (SIG_ERR);
  69     return (oact.sa_handler);
  70 #else
  71     return signal (sig, func);
  72 #endif
  73 }
  74
  75
  76 /*
  77  * A version of the function `signal' that will set
  78  * the handler of `sig' to `func' if the signal is
  79  * not currently set to SIG_IGN.  Also uses reliable
  80  * signals if available.
  81  */
  82 SIGNAL_HANDLER
  83 SIGNAL2 (int sig, SIGNAL_HANDLER func)
  84 {
  85 #ifdef POSIX_SIGNALS
  86     struct sigaction act, oact;
  87
  88     if (sigaction(sig, NULL, &oact) < 0)
  89         return (SIG_ERR);
  90     if (oact.sa_handler != SIG_IGN) {
  91         act.sa_handler = func;
  92         sigemptyset(&act.sa_mask);
  93         act.sa_flags = 0;
  94
  95         if (sig == SIGALRM) {
  96 # ifdef SA_INTERRUPT
  97             act.sa_flags |= SA_INTERRUPT;     /* SunOS */
  98 # endif
  99         } else {
 100 # ifdef SA_RESTART
 101             act.sa_flags |= SA_RESTART;       /* SVR4, BSD4.4 */
 102 # endif
 103         }
 104         if (sigaction(sig, &act, &oact) < 0)
 105             return (SIG_ERR);
 106     }
 107     return (oact.sa_handler);
 108 #else
 109     SIGNAL_HANDLER ofunc;
 110
 111     if ((ofunc = signal (sig, SIG_IGN)) != SIG_IGN)
 112         signal (sig, func);
 113     return ofunc;
 114 #endif
 115 }
 116