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

   1
   2 /*
   3  * signals.c -- general signals interface for nmh
   4  *
   5  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   6  * COPYRIGHT file in the root directory of the nmh distribution for
   7  * complete copyright information.
   8  */
   9
  10 #include <h/mh.h>
  11 #include <h/signals.h>
  12
  13 /* sbr/m_mktemp.c */
  14 extern void remove_registered_files(int);
  15
  16
  17 /*
  18  * A version of the function `signal' that uses reliable
  19  * signals, if the machine supports them.  Also, (assuming
  20  * OS support), it restarts interrupted system calls for all
  21  * signals except SIGALRM.
  22  *
  23  * Since we are now assuming POSIX signal support everywhere, we always
  24  * use reliable signals.
  25  */
  26
  27 SIGNAL_HANDLER
  28 SIGNAL (int sig, SIGNAL_HANDLER func)
  29 {
  30     struct sigaction act, oact;
  31
  32     act.sa_handler = func;
  33     sigemptyset(&act.sa_mask);
  34     act.sa_flags = 0;
  35
  36     if (sig == SIGALRM) {
  37 # ifdef SA_INTERRUPT
  38         act.sa_flags |= SA_INTERRUPT;     /* SunOS */
  39 # endif
  40     } else {
  41 # ifdef SA_RESTART
  42         act.sa_flags |= SA_RESTART;       /* SVR4, BSD4.4 */
  43 # endif
  44     }
  45     if (sigaction(sig, &act, &oact) < 0)
  46         return (SIG_ERR);
  47     return (oact.sa_handler);
  48 }
  49
  50
  51 /*
  52  * A version of the function `signal' that will set
  53  * the handler of `sig' to `func' if the signal is
  54  * not currently set to SIG_IGN.  Also uses reliable
  55  * signals if available.
  56  */
  57 SIGNAL_HANDLER
  58 SIGNAL2 (int sig, SIGNAL_HANDLER func)
  59 {
  60     struct sigaction act, oact;
  61
  62     if (sigaction(sig, NULL, &oact) < 0)
  63         return (SIG_ERR);
  64     if (oact.sa_handler != SIG_IGN) {
  65         act.sa_handler = func;
  66         sigemptyset(&act.sa_mask);
  67         act.sa_flags = 0;
  68
  69         if (sig == SIGALRM) {
  70 # ifdef SA_INTERRUPT
  71             act.sa_flags |= SA_INTERRUPT;     /* SunOS */
  72 # endif
  73         } else {
  74 # ifdef SA_RESTART
  75             act.sa_flags |= SA_RESTART;       /* SVR4, BSD4.4 */
  76 # endif
  77         }
  78         if (sigaction(sig, &act, &oact) < 0)
  79             return (SIG_ERR);
  80     }
  81     return (oact.sa_handler);
  82 }
  83
  84
  85 /*
  86  * For use by nmh_init().
  87  */
  88 int
  89 setup_signal_handlers() {
  90     /*
  91      * Catch HUP, INT, QUIT, and TERM so that we can clean up tmp
  92      * files when the user terminates the process early.  And also a
  93      * few other common signals that can be thrown due to bugs, stack
  94      * overflow, etc.
  95      */
  96
  97     if (SIGNAL(SIGHUP,  remove_registered_files) == SIG_ERR  ||
  98         SIGNAL(SIGINT,  remove_registered_files) == SIG_ERR  ||
  99         SIGNAL(SIGQUIT, remove_registered_files) == SIG_ERR  ||
 100         SIGNAL(SIGTERM, remove_registered_files) == SIG_ERR  ||
 101         SIGNAL(SIGILL,  remove_registered_files) == SIG_ERR  ||
 102 #       ifdef SIGBUS
 103         SIGNAL(SIGBUS,  remove_registered_files) == SIG_ERR  ||
 104 #       endif
 105         SIGNAL(SIGSEGV, remove_registered_files) == SIG_ERR) {
 106         return NOTOK;
 107     }
 108
 109     return OK;
 110 }