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                         common_log(LOG_ERR, "Could not fork.");
  32                         return false;
  33                 } else if ($pid > 0) { # parent
  34                         common_log(LOG_INFO, "Successfully forked.");
  35                         exit(0);
  36                 } else { # child
  37                         return true;
  38                 }
  39         }
  40
  41         function alreadyRunning() {
  42
  43                 $pidfilename = $this->pidFilename();
  44
  45                 if (!$pidfilename) {
  46                         return false;
  47                 }
  48
  49                 if (!file_exists($pidfilename)) {
  50                         return false;
  51                 }
  52                 $contents = file_get_contents($pidfilename);
  53                 if (posix_kill(trim($contents),0)) {
  54                         return true;
  55                 } else {
  56                         return false;
  57                 }
  58         }
  59
  60         function writePidFile() {
  61                 $pidfilename = $this->pidFilename();
  62
  63                 if (!$pidfilename) {
  64                         return false;
  65                 }
  66
  67             return file_put_contents($pidfilename, posix_getpid() . "\n");
  68         }
  69
  70         function clearPidFile() {
  71                 $pidfilename = $this->pidFilename();
  72                 if (!$pidfilename) {
  73                     return false;
  74                 }
  75                 return unlink($pidfilename);
  76         }
  77
  78         function pidFilename() {
  79                 $piddir = common_config('daemon', 'piddir');
  80                 if (!$piddir) {
  81                         return NULL;
  82                 }
  83                 $name = $this->name();
  84                 if (!$name) {
  85                         return NULL;
  86                 }
  87                 return $piddir . '/' . $name . '.pid';
  88         }
  89
  90         function changeUser() {
  91
  92                 $username = common_config('daemon', 'user');
  93
  94                 if ($username) {
  95                         $user_info = posix_getpwnam($username);
  96                         if (!$user_info) {
  97                                 common_log(LOG_WARNING, 'Ignoring unknown user for daemon: ' . $username);
  98                         } else {
  99                                 common_log(LOG_INFO, "Setting user to " . $username);
 100                                 posix_setuid($user_info['uid']);
 101                         }
 102                 }
 103
 104                 $groupname = common_config('daemon', 'group');
 105
 106                 if ($groupname) {
 107                         $group_info = posix_getgrnam($groupname);
 108                         if (!$group_info) {
 109                                 common_log(LOG_WARNING, 'Ignoring unknown group for daemon: ' . $groupname);
 110                         } else {
 111                                 common_log(LOG_INFO, "Setting group to " . $groupname);
 112                                 posix_setgid($group_info['gid']);
 113                         }
 114                 }
 115         }
 116
 117         function runOnce() {
 118                 if ($this->alreadyRunning()) {
 119                         common_log(LOG_INFO, $this->name() . ' already running. Exiting.');
 120                         exit(0);
 121                 }
 122                 if ($this->background()) {
 123                         $this->writePidFile();
 124                         $this->changeUser();
 125                         $this->run();
 126                         $this->clearPidFile();
 127                 }
 128         }
 129
 130         function run() {
 131                 return true;
 132         }
 133 }