/* $Id: daemon.c,v 1.5 2005-08-15 03:54:31 rjkaes Exp $ * * This file contains functions which are useful when writing a * daemon process. The functions include a "makedaemon" function and * a function to portably set a signal handler. * * Copyright (C) 2002 Robert James Kaes (rjkaes@users.sourceforge.net) * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2, or (at your option) any * later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #include "tinyproxy.h" #include "daemon.h" /* * Fork a child process and then kill the parent so make the calling * program a daemon process. */ void makedaemon(void) { if (fork() != 0) exit(0); setsid(); set_signal_handler(SIGHUP, SIG_IGN); if (fork() != 0) exit(0); chdir("/"); umask(077); #if NDEBUG /* * When not in debugging mode, close the standard file * descriptors. */ close(0); close(1); close(2); #endif } /* * Pass a signal number and a signal handling function into this function * to handle signals sent to the process. */ signal_func * set_signal_handler(int signo, signal_func * func) { struct sigaction act, oact; act.sa_handler = func; sigemptyset(&act.sa_mask); act.sa_flags = 0; if (signo == SIGALRM) { #ifdef SA_INTERRUPT act.sa_flags |= SA_INTERRUPT; /* SunOS 4.x */ #endif } else { #ifdef SA_RESTART act.sa_flags |= SA_RESTART; /* SVR4, 4.4BSD */ #endif } if (sigaction(signo, &act, &oact) < 0) return SIG_ERR; return oact.sa_handler; }