Harald Welte | b6cb023 | 2010-08-25 19:24:26 +0200 | [diff] [blame] | 1 | /* Process handling support code */ |
| 2 | |
| 3 | /* (C) 2010 by Harald Welte <laforge@gnumonks.org> |
| 4 | * All Rights Reserved |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License along |
| 17 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 18 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 19 | * |
| 20 | */ |
| 21 | |
| 22 | #include <stdio.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <unistd.h> |
| 25 | #include <errno.h> |
| 26 | #include <sys/types.h> |
| 27 | #include <sys/stat.h> |
| 28 | |
| 29 | int osmo_daemonize(void) |
| 30 | { |
| 31 | int rc; |
| 32 | pid_t pid, sid; |
| 33 | |
| 34 | /* Check if parent PID == init, in which case we are already a daemon */ |
| 35 | if (getppid() == 1) |
| 36 | return -EEXIST; |
| 37 | |
| 38 | /* Fork from the parent process */ |
| 39 | pid = fork(); |
| 40 | if (pid < 0) { |
| 41 | /* some error happened */ |
| 42 | return pid; |
| 43 | } |
| 44 | |
| 45 | if (pid > 0) { |
| 46 | /* if we have received a positive PID, then we are the parent |
| 47 | * and can exit */ |
| 48 | exit(0); |
| 49 | } |
| 50 | |
| 51 | /* FIXME: do we really want this? */ |
| 52 | umask(0); |
| 53 | |
| 54 | /* Create a new session and set process group ID */ |
| 55 | sid = setsid(); |
| 56 | if (sid < 0) |
| 57 | return sid; |
| 58 | |
| 59 | /* Change to the /tmp directory, which prevents the CWD from being locked |
| 60 | * and unable to remove it */ |
| 61 | rc = chdir("/tmp"); |
| 62 | if (rc < 0) |
| 63 | return rc; |
| 64 | |
| 65 | /* Redirect stdio to /dev/null */ |
| 66 | freopen("/dev/null", "r", stdin); |
| 67 | freopen("/dev/null", "w", stdout); |
| 68 | freopen("/dev/null", "w", stderr); |
| 69 | |
| 70 | return 0; |
| 71 | } |