source/lib/signal.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    signal handling functions
   5
   6    Copyright (C) Andrew Tridgell 1998
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25
  26 /****************************************************************************
  27 catch child exits
  28 ****************************************************************************/
  29 static void sig_cld(int signum)
  30 {
  31         while (sys_waitpid((pid_t)-1,(int *)NULL, WNOHANG) > 0) ;
  32
  33         CatchSignal(SIGCLD, sig_cld);
  34 }
  35
  36
  37
  38 /*******************************************************************
  39 block sigs
  40 ********************************************************************/
  41 void BlockSignals(BOOL block,int signum)
  42 {
  43 #ifdef HAVE_SIGPROCMASK
  44         sigset_t set;
  45         sigemptyset(&set);
  46         sigaddset(&set,signum);
  47         sigprocmask(block?SIG_BLOCK:SIG_UNBLOCK,&set,NULL);
  48 #elif defined(HAVE_SIGBLOCK)
  49         int block_mask = sigmask(signum);
  50         static int oldmask = 0;
  51         if (block) {
  52                 oldmask = sigblock(block_mask);
  53         } else {
  54                 sigsetmask(oldmask);
  55         }
  56 #else
  57         /* yikes! This platform can't block signals? */
  58         static int done;
  59         if (!done) {
  60                 DEBUG(0,("WARNING: No signal blocking available\n"));
  61                 done=1;
  62         }
  63 #endif
  64 }
  65
  66
  67
  68 /*******************************************************************
  69 catch a signal. This should implement the following semantics:
  70
  71 1) the handler remains installed after being called
  72 2) the signal should be blocked during handler execution
  73 ********************************************************************/
  74 void CatchSignal(int signum,void (*handler)(int ))
  75 {
  76 #ifdef HAVE_SIGACTION
  77         struct sigaction act;
  78
  79         ZERO_STRUCT(act);
  80
  81         act.sa_handler = handler;
  82 #ifdef SA_RESTART
  83         act.sa_flags = SA_RESTART;
  84 #endif
  85         sigemptyset(&act.sa_mask);
  86         sigaddset(&act.sa_mask,signum);
  87         sigaction(signum,&act,NULL);
  88 #else
  89         /* FIXME: need to handle sigvec and systems with broken signal() */
  90         signal(signum, handler);
  91 #endif
  92 }
  93
  94
  95
  96 /*******************************************************************
  97 ignore SIGCLD via whatever means is necessary for this OS
  98 ********************************************************************/
  99 void CatchChild(void)
 100 {
 101         CatchSignal(SIGCLD, sig_cld);
 102 }