Add helper function 'osmo_daemonize()' to convert process into daemon
diff --git a/src/process.c b/src/process.c
new file mode 100644
index 0000000..ab4b37e
--- /dev/null
+++ b/src/process.c
@@ -0,0 +1,71 @@
+/* Process handling support code */
+
+/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
+ * All Rights Reserved
+ *
+ * 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 of the License, 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int osmo_daemonize(void)
+{
+ int rc;
+ pid_t pid, sid;
+
+ /* Check if parent PID == init, in which case we are already a daemon */
+ if (getppid() == 1)
+ return -EEXIST;
+
+ /* Fork from the parent process */
+ pid = fork();
+ if (pid < 0) {
+ /* some error happened */
+ return pid;
+ }
+
+ if (pid > 0) {
+ /* if we have received a positive PID, then we are the parent
+ * and can exit */
+ exit(0);
+ }
+
+ /* FIXME: do we really want this? */
+ umask(0);
+
+ /* Create a new session and set process group ID */
+ sid = setsid();
+ if (sid < 0)
+ return sid;
+
+ /* Change to the /tmp directory, which prevents the CWD from being locked
+ * and unable to remove it */
+ rc = chdir("/tmp");
+ if (rc < 0)
+ return rc;
+
+ /* Redirect stdio to /dev/null */
+ freopen("/dev/null", "r", stdin);
+ freopen("/dev/null", "w", stdout);
+ freopen("/dev/null", "w", stderr);
+
+ return 0;
+}