includes/libs/filebackend/fsfile/TempFSFile.php

   1 <?php
   2 /**
   3  * Location holder of files stored temporarily
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup FileBackend
  22  */
  23
  24 /**
  25  * This class is used to hold the location and do limited manipulation
  26  * of files stored temporarily (this will be whatever wfTempDir() returns)
  27  *
  28  * @ingroup FileBackend
  29  */
  30 class TempFSFile extends FSFile {
  31         /** @var bool Garbage collect the temp file */
  32         protected $canDelete = false;
  33
  34         /** @var array Map of (path => 1) for paths to delete on shutdown */
  35         protected static $pathsCollect = null;
  36
  37         public function __construct( $path ) {
  38                 parent::__construct( $path );
  39
  40                 if ( self::$pathsCollect === null ) {
  41                         self::$pathsCollect = [];
  42                         register_shutdown_function( [ __CLASS__, 'purgeAllOnShutdown' ] );
  43                 }
  44         }
  45
  46         /**
  47          * Make a new temporary file on the file system.
  48          * Temporary files may be purged when the file object falls out of scope.
  49          *
  50          * @param string $prefix
  51          * @param string $extension Optional file extension
  52          * @param string|null $tmpDirectory Optional parent directory
  53          * @return TempFSFile|null
  54          */
  55         public static function factory( $prefix, $extension = '', $tmpDirectory = null ) {
  56                 $ext = ( $extension != '' ) ? ".{$extension}" : '';
  57
  58                 $attempts = 5;
  59                 while ( $attempts-- ) {
  60                         $hex = sprintf( '%06x%06x', mt_rand( 0, 0xffffff ), mt_rand( 0, 0xffffff ) );
  61                         if ( !is_string( $tmpDirectory ) ) {
  62                                 $tmpDirectory = self::getUsableTempDirectory();
  63                         }
  64                         $path = wfTempDir() . '/' . $prefix . $hex . $ext;
  65                         MediaWiki\suppressWarnings();
  66                         $newFileHandle = fopen( $path, 'x' );
  67                         MediaWiki\restoreWarnings();
  68                         if ( $newFileHandle ) {
  69                                 fclose( $newFileHandle );
  70                                 $tmpFile = new self( $path );
  71                                 $tmpFile->autocollect();
  72                                 // Safely instantiated, end loop.
  73                                 return $tmpFile;
  74                         }
  75                 }
  76
  77                 // Give up
  78                 return null;
  79         }
  80
  81         /**
  82          * @return string Filesystem path to a temporary directory
  83          * @throws RuntimeException
  84          */
  85         public static function getUsableTempDirectory() {
  86                 $tmpDir = array_map( 'getenv', [ 'TMPDIR', 'TMP', 'TEMP' ] );
  87                 $tmpDir[] = sys_get_temp_dir();
  88                 $tmpDir[] = ini_get( 'upload_tmp_dir' );
  89                 foreach ( $tmpDir as $tmp ) {
  90                         if ( $tmp != '' && is_dir( $tmp ) && is_writable( $tmp ) ) {
  91                                 return $tmp;
  92                         }
  93                 }
  94
  95                 // PHP on Windows will detect C:\Windows\Temp as not writable even though PHP can write to
  96                 // it so create a directory within that called 'mwtmp' with a suffix of the user running
  97                 // the current process.
  98                 // The user is included as if various scripts are run by different users they will likely
  99                 // not be able to access each others temporary files.
 100                 if ( strtoupper( substr( PHP_OS, 0, 3 ) ) === 'WIN' ) {
 101                         $tmp = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'mwtmp-' . get_current_user();
 102                         if ( !file_exists( $tmp ) ) {
 103                                 mkdir( $tmp );
 104                         }
 105                         if ( is_dir( $tmp ) && is_writable( $tmp ) ) {
 106                                 return $tmp;
 107                         }
 108                 }
 109
 110                 throw new RuntimeException(
 111                         'No writable temporary directory could be found. ' .
 112                         'Please explicitly specify a writable directory in configuration.' );
 113         }
 114
 115         /**
 116          * Purge this file off the file system
 117          *
 118          * @return bool Success
 119          */
 120         public function purge() {
 121                 $this->canDelete = false; // done
 122                 MediaWiki\suppressWarnings();
 123                 $ok = unlink( $this->path );
 124                 MediaWiki\restoreWarnings();
 125
 126                 unset( self::$pathsCollect[$this->path] );
 127
 128                 return $ok;
 129         }
 130
 131         /**
 132          * Clean up the temporary file only after an object goes out of scope
 133          *
 134          * @param object $object
 135          * @return TempFSFile This object
 136          */
 137         public function bind( $object ) {
 138                 if ( is_object( $object ) ) {
 139                         if ( !isset( $object->tempFSFileReferences ) ) {
 140                                 // Init first since $object might use __get() and return only a copy variable
 141                                 $object->tempFSFileReferences = [];
 142                         }
 143                         $object->tempFSFileReferences[] = $this;
 144                 }
 145
 146                 return $this;
 147         }
 148
 149         /**
 150          * Set flag to not clean up after the temporary file
 151          *
 152          * @return TempFSFile This object
 153          */
 154         public function preserve() {
 155                 $this->canDelete = false;
 156
 157                 unset( self::$pathsCollect[$this->path] );
 158
 159                 return $this;
 160         }
 161
 162         /**
 163          * Set flag clean up after the temporary file
 164          *
 165          * @return TempFSFile This object
 166          */
 167         public function autocollect() {
 168                 $this->canDelete = true;
 169
 170                 self::$pathsCollect[$this->path] = 1;
 171
 172                 return $this;
 173         }
 174
 175         /**
 176          * Try to make sure that all files are purged on error
 177          *
 178          * This method should only be called internally
 179          */
 180         public static function purgeAllOnShutdown() {
 181                 foreach ( self::$pathsCollect as $path ) {
 182                         MediaWiki\suppressWarnings();
 183                         unlink( $path );
 184                         MediaWiki\restoreWarnings();
 185                 }
 186         }
 187
 188         /**
 189          * Cleans up after the temporary file by deleting it
 190          */
 191         function __destruct() {
 192                 if ( $this->canDelete ) {
 193                         $this->purge();
 194                 }
 195         }
 196 }