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

   1
   2 /*
   3  * signals.c -- general signals interface for nmh
   4  *
   5  * $Id$
   6  *
   7  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   8  * COPYRIGHT file in the root directory of the nmh distribution for
   9  * complete copyright information.
  10  */
  11
  12 #include <h/mh.h>
  13 #include <h/signals.h>
  14
  15
  16 int
  17 SIGPROCMASK (int how, const sigset_t *set, sigset_t *oset)
  18 {
  19 #ifdef POSIX_SIGNALS
  20     return sigprocmask(how, set, oset);
  21 #else
  22 # ifdef BSD_SIGNALS
  23     switch(how) {
  24     case SIG_BLOCK:
  25         *oset = sigblock(*set);
  26         break;
  27     case SIG_UNBLOCK:
  28         sigfillset(*oset);
  29         *oset = sigsetmask(*oset);
  30         sigsetmask(*oset & ~(*set));
  31         break;
  32     case SIG_SETMASK:
  33         *oset = sigsetmask(*set);
  34         break;
  35     default:
  36         adios(NULL, "unknown flag in SIGPROCMASK");
  37         break;
  38     }
  39     return 0;
  40 # endif
  41 #endif
  42 }
  43
  44
  45 /*
  46  * A version of the function `signal' that uses reliable
  47  * signals, if the machine supports them.  Also, (assuming
  48  * OS support), it restarts interrupted system calls for all
  49  * signals except SIGALRM.
  50  */
  51
  52 SIGNAL_HANDLER
  53 SIGNAL (int sig, SIGNAL_HANDLER func)
  54 {
  55 #ifdef POSIX_SIGNALS
  56     struct sigaction act, oact;
  57
  58     act.sa_handler = func;
  59     sigemptyset(&act.sa_mask);
  60     act.sa_flags = 0;
  61
  62     if (sig == SIGALRM) {
  63 # ifdef SA_INTERRUPT
  64         act.sa_flags |= SA_INTERRUPT;     /* SunOS */
  65 # endif
  66     } else {
  67 # ifdef SA_RESTART
  68         act.sa_flags |= SA_RESTART;       /* SVR4, BSD4.4 */
  69 # endif
  70     }
  71     if (sigaction(sig, &act, &oact) < 0)
  72         return (SIG_ERR);
  73     return (oact.sa_handler);
  74 #else
  75     return signal (sig, func);
  76 #endif
  77 }
  78
  79
  80 /*
  81  * A version of the function `signal' that will set
  82  * the handler of `sig' to `func' if the signal is
  83  * not currently set to SIG_IGN.  Also uses reliable
  84  * signals if available.
  85  */
  86 SIGNAL_HANDLER
  87 SIGNAL2 (int sig, SIGNAL_HANDLER func)
  88 {
  89 #ifdef POSIX_SIGNALS
  90     struct sigaction act, oact;
  91
  92     if (sigaction(sig, NULL, &oact) < 0)
  93         return (SIG_ERR);
  94     if (oact.sa_handler != SIG_IGN) {
  95         act.sa_handler = func;
  96         sigemptyset(&act.sa_mask);
  97         act.sa_flags = 0;
  98
  99         if (sig == SIGALRM) {
 100 # ifdef SA_INTERRUPT
 101             act.sa_flags |= SA_INTERRUPT;     /* SunOS */
 102 # endif
 103         } else {
 104 # ifdef SA_RESTART
 105             act.sa_flags |= SA_RESTART;       /* SVR4, BSD4.4 */
 106 # endif
 107         }
 108         if (sigaction(sig, &act, &oact) < 0)
 109             return (SIG_ERR);
 110     }
 111     return (oact.sa_handler);
 112 #else
 113     SIGNAL_HANDLER ofunc;
 114
 115     if ((ofunc = signal (sig, SIG_IGN)) != SIG_IGN)
 116         signal (sig, func);
 117     return ofunc;
 118 #endif
 119 }
 120