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

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