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

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