Add helper function 'osmo_daemonize()' to convert process into daemon

diff --git a/src/Makefile.am b/src/Makefile.am
index e197e17..765fbb8 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -13,7 +13,7 @@ libosmocore_la_SOURCES = timer.c select.c signal.c msgb.c rxlev_stat.c \
                         tlv_parser.c bitvec.c comp128.c gsm_utils.c statistics.c \
                         write_queue.c utils.c rsl.c gsm48.c gsm48_ie.c \
                         logging.c gsm0808.c rate_ctr.c gsmtap_util.c \
-                        gprs_cipher_core.c crc16.c panic.c
+                        gprs_cipher_core.c crc16.c panic.c process.c
 
 if ENABLE_PLUGIN
 libosmocore_la_SOURCES += plugin.c

diff --git a/src/process.c b/src/process.c
new file mode 100644 (file)
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;
+}