text: /*----------------------------------------------------------------------------*/
  /* Hobbit monitor library.                                                    */
  /*                                                                            */
  /* This is a library module, part of libbbgen.                                */
  /* It contains routines for handling of signals and crashes.                  */
  /*                                                                            */
  /* Copyright (C) 2002-2009 Henrik Storner <henrik@storner.dk>                 */
  /*                                                                            */
  /* This program is released under the GNU General Public License (GPL),       */
  /* version 2. See the file "COPYING" for details.                             */
  /*                                                                            */
  /*----------------------------------------------------------------------------*/
  
  static char rcsid[] = "$Id$";
  
  #include <limits.h>
  #include <signal.h>
  #include <string.h>
  #include <sys/types.h>
  #include <sys/time.h>
  #include <sys/resource.h>
  #include <unistd.h>
  #include <stdlib.h>
  #include <stdio.h>
  
  #include "libbbgen.h"
  
  /* Data used while crashing - cannot depend on the stack being usable */
  static char signal_bbcmd[PATH_MAX];
  static char signal_bbdisp[1024];
  static char signal_msg[1024];
  static char signal_bbtmp[PATH_MAX];
  
  
  static void sigsegv_handler(int signum)
  {
  	/*
  	 * This is a signal handler. Only a very limited number of 
  	 * library routines can be safely used here, according to
  	 * Posix: http://www.opengroup.org/onlinepubs/007904975/functions/xsh_chap02_04.html#tag_02_04_03
  	 * Do not use string, stdio etc. - just basic system calls.
  	 * That is why we need to setup all of the strings in advance.
  	 */
  
  	signal(signum, SIG_DFL);
  
  	/* 
  	 * Try to fork a child to send in an alarm message.
  	 * If the fork fails, then just attempt to exec() the BB command
  	 */
  	if (fork() <= 0) {
  		execl(signal_bbcmd, "bbgen-signal", signal_bbdisp, signal_msg, NULL);
  	}
  
  	/* Dump core and abort */
  	chdir(signal_bbtmp);
  	abort();
  }
  
  static void sigusr2_handler(int signum)
  {
  	/* SIGUSR2 toggles debugging */
  
  	if (debug) {
  		dbgprintf("Debug OFF\n");
  		debug = 0;
  	}
  	else {
  		debug = 1;
  		dbgprintf("Debug ON\n");
  	}
  }
  
  void setup_signalhandler(char *programname)
  {
  	struct rlimit lim;
  	struct sigaction sa;
  
  	MEMDEFINE(signal_bbcmd);
  	MEMDEFINE(signal_bbdisp);
  	MEMDEFINE(signal_bbtmp);
  	MEMDEFINE(signal_msg);
  
  	memset(&sa, 0, sizeof(sa));
  	sa.sa_handler = sigsegv_handler;
  
  	/*
  	 * Try to allow ourselves to generate core files
  	 */
  	getrlimit(RLIMIT_CORE, &lim);
  	lim.rlim_cur = RLIM_INFINITY;
  	setrlimit(RLIMIT_CORE, &lim);
  
  	if (xgetenv("BB") == NULL) return;
  	if (xgetenv("BBDISP") == NULL) return;
  
  	/*
  	 * Used inside signal-handler. Must be setup in
  	 * advance.
  	 */
  	strcpy(signal_bbcmd, xgetenv("BB"));
  	strcpy(signal_bbdisp, xgetenv("BBDISP"));
  	strcpy(signal_bbtmp, xgetenv("BBTMP"));
  	sprintf(signal_msg, "status %s.%s red - Program crashed\n\nFatal signal caught!\n", 
  		(xgetenv("MACHINE") ? xgetenv("MACHINE") : "BBDISPLAY"), programname);
  
  	sigaction(SIGSEGV, &sa, NULL);
  	sigaction(SIGILL, &sa, NULL);
  #ifdef SIGBUS
  	sigaction(SIGBUS, &sa, NULL);
  #endif
  
  	/*
  	 * After lengthy debugging and perusing of mail archives:
  	 * Need to ignore SIGPIPE since FreeBSD (and others?) can throw this
  	 * on a write() instead of simply returning -EPIPE like any sane
  	 * OS would.
  	 */
  	signal(SIGPIPE, SIG_IGN);
  
  	/* Ignore SIGUSR1 unless explicitly set by main program */
  	signal (SIGUSR1, SIG_IGN);
  
  	/* SIGUSR2 toggles debugging */
  	memset(&sa, 0, sizeof(sa));
  	sa.sa_handler = sigusr2_handler;
  	sigaction(SIGUSR2, &sa, NULL);
  }
  
  