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/* 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 */
/* since C89/C99 says stderr is a macro, we can safely do this! */
#ifdef stderr
freopen("/dev/null", "r", stdin);
freopen("/dev/null", "w", stdout);
freopen("/dev/null", "w", stderr);
#endif
return 0;
}
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