+/* $Header: /cvsroot/wikipedia/willow/src/bin/willow/daemon.c,v 1.1 2005/05/02 19:15:21 kateturner Exp $ */
+/* $NetBSD: daemon.c,v 1.9 2003/08/07 16:42:46 agc Exp $ */
+/*-
+ * Copyright (c) 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ * Copyright (c) 2010
+ * Stewart Smith
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined __SUNPRO_C || defined __DECC || defined __HP_cc
+# pragma ident "@(#)$Header: /cvsroot/wikipedia/willow/src/bin/willow/daemon.c,v 1.1 2005/05/02 19:15:21 kateturner Exp $"
+# pragma ident "$NetBSD: daemon.c,v 1.9 2003/08/07 16:42:46 agc Exp $"
+#endif
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/select.h>
+
+int daemonize(int nochdir, int noclose, int wait_sigusr1);
+int daemon_is_ready(void);
+void sigusr1_handler(int sig);
+
+pid_t parent_pid;
+
+void sigusr1_handler(int sig)
+{
+ if (sig == SIGUSR1)
+ _exit(EXIT_SUCCESS);
+}
+
+int daemon_is_ready()
+{
+ kill(parent_pid, SIGUSR1);
+ return 0;
+}
+
+int daemonize(int nochdir, int noclose, int wait_sigusr1)
+{
+ int fd;
+ pid_t child= -1;
+
+ parent_pid= getpid();
+ signal(SIGUSR1, sigusr1_handler);
+
+ child= fork();
+
+ switch (child)
+ {
+ case -1:
+ return (-1);
+ case 0:
+ break;
+ default:
+ if (wait_sigusr1)
+ {
+ /* parent */
+ int exit_code= -1;
+ int status;
+ while (waitpid(child, &status, 0) != child);
+ if (WIFEXITED(status))
+ {
+ exit_code= WEXITSTATUS(status);
+ }
+ if (WIFSIGNALED(status))
+ {
+ exit_code= -1;
+ }
+ _exit(exit_code);
+ }
+ else
+ {
+ _exit(EXIT_SUCCESS);
+ }
+ }
+
+ /* child */
+ if (setsid() == -1)
+ return (-1);
+
+ if (nochdir == 0) {
+ if(chdir("/") != 0) {
+ perror("chdir");
+ return (-1);
+ }
+ }
+
+ if (noclose == 0 && (fd = open("/dev/null", O_RDWR, 0)) != -1) {
+ if(dup2(fd, STDIN_FILENO) < 0) {
+ perror("dup2 stdin");
+ return (-1);
+ }
+ if(dup2(fd, STDOUT_FILENO) < 0) {
+ perror("dup2 stdout");
+ return (-1);
+ }
+ if(dup2(fd, STDERR_FILENO) < 0) {
+ perror("dup2 stderr");
+ return (-1);
+ }
+
+ if (fd > STDERR_FILENO) {
+ if(close(fd) < 0) {
+ perror("close");
+ return (-1);
+ }
+ }
+ }
+ return (0);
+}