The Tcpdump Group git mirrors - tcpdump/blob - setsignal.c

   1 /*
   2  * Copyright (c) 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #ifndef lint
  23 static const char rcsid[] =
  24     "@(#) $Header: /tcpdump/master/tcpdump/setsignal.c,v 1.5 1999-11-21 09:37:04 fenner Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <sys/types.h>
  32
  33 #ifdef HAVE_MEMORY_H
  34 #include <memory.h>
  35 #endif
  36 #include <signal.h>
  37 #ifdef HAVE_SIGACTION
  38 #include <string.h>
  39 #endif
  40
  41 #include "gnuc.h"
  42 #ifdef HAVE_OS_PROTO_H
  43 #include "os-proto.h"
  44 #endif
  45
  46 #include "setsignal.h"
  47
  48 /*
  49  * An os independent signal() with BSD semantics, e.g. the signal
  50  * catcher is restored following service of the signal.
  51  *
  52  * When sigset() is available, signal() has SYSV semantics and sigset()
  53  * has BSD semantics and call interface. Unfortunately, Linux does not
  54  * have sigset() so we use the more complicated sigaction() interface
  55  * there.
  56  *
  57  * Did I mention that signals suck?
  58  */
  59 RETSIGTYPE
  60 (*setsignal (int sig, RETSIGTYPE (*func)(int)))(int)
  61 {
  62 #ifdef HAVE_SIGACTION
  63         struct sigaction old, new;
  64
  65         memset(&new, 0, sizeof(new));
  66         new.sa_handler = func;
  67 #ifdef SA_RESTART
  68         new.sa_flags |= SA_RESTART;
  69 #endif
  70         if (sigaction(sig, &new, &old) < 0)
  71                 return (SIG_ERR);
  72         return (old.sa_handler);
  73
  74 #else
  75 #ifdef HAVE_SIGSET
  76         return (sigset(sig, func));
  77 #else
  78         return (signal(sig, func));
  79 #endif
  80 #endif
  81 }
  82