lib/daemon.php

   1 <?php
   2 /*
   3  * Laconica - a distributed open-source microblogging tool
   4  * Copyright (C) 2008, Controlez-Vous, Inc.
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU Affero General Public License as published by
   8  * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Affero General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 if (!defined('LACONICA')) { exit(1); }
  21
  22 class Daemon {
  23
  24         function name() {
  25                 return NULL;
  26         }
  27
  28         function background() {
  29                 $pid = pcntl_fork();
  30                 if ($pid < 0) { # error
  31                         return false;
  32                 } else if ($pid > 0) { # parent
  33                         common_log(LOG_INFO, "Successfully forked.");
  34                         exit(0);
  35                 } else { # child
  36                         return true;
  37                 }
  38         }
  39
  40         function alreadyRunning() {
  41
  42                 $pidfilename = $this->pidFilename();
  43
  44                 if (!$pidfilename) {
  45                         return false;
  46                 }
  47
  48                 if (!file_exists($pidfilename)) {
  49                         return false;
  50                 }
  51                 $contents = file_get_contents($pidfilename);
  52                 if (posix_kill(trim($contents),0)) {
  53                         return true;
  54                 } else {
  55                         return false;
  56                 }
  57         }
  58
  59         function writePidFile() {
  60                 $pidfilename = $this->pidFilename();
  61
  62                 if (!$pidfilename) {
  63                         return false;
  64                 }
  65
  66                 file_put_contents($pidfilename, posix_getpid() . "\n");
  67         }
  68
  69         function clearPidFile() {
  70                 $pidfilename = $this->pidFilename();
  71                 unlink($pidfilename);
  72         }
  73
  74         function pidFilename() {
  75                 $piddir = common_config('daemon', 'piddir');
  76                 if (!$piddir) {
  77                         return NULL;
  78                 }
  79                 $name = $this->name();
  80                 if (!$name) {
  81                         return NULL;
  82                 }
  83                 return $piddir . '/' . $name . '.pid';
  84         }
  85
  86         function changeUser() {
  87
  88                 $username = common_config('daemon', 'user');
  89
  90                 if ($username) {
  91                         $user_info = posix_getpwnam($username);
  92                         if (!$user_info) {
  93                                 common_log(LOG_WARNING, 'Ignoring unknown user for daemon: ' . $username);
  94                         } else {
  95                                 common_log(LOG_INFO, "Setting user to " . $username);
  96                                 posix_setuid($user_info['uid']);
  97                         }
  98                 }
  99
 100                 $groupname = common_config('daemon', 'group');
 101
 102                 if ($groupname) {
 103                         $group_info = posix_getgrnam($groupname);
 104                         if (!$group_info) {
 105                                 common_log(LOG_WARNING, 'Ignoring unknown group for daemon: ' . $groupname);
 106                         } else {
 107                                 common_log(LOG_INFO, "Setting group to " . $groupname);
 108                                 posix_setgid($group_info['gid']);
 109                         }
 110                 }
 111         }
 112
 113         function runOnce() {
 114                 if ($this->alreadyRunning()) {
 115                         common_log(LOG_INFO, $this->name() . ' already running. Exiting.');
 116                         exit(0);
 117                 }
 118                 if ($this->background()) {
 119                         $this->writePidFile();
 120                         $this->changeUser();
 121                         $this->run();
 122                         $this->clearPidFile();
 123                 }
 124         }
 125
 126         function run() {
 127                 return true;
 128         }
 129 }