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   1  <?php
   2  /**
   3   * Module defining helper functions for detecting and dealing with MIME types.
   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   */
  22  
  23  /**
  24   * Defines a set of well known MIME types
  25   * This is used as a fallback to mime.types files.
  26   * An extensive list of well known MIME types is provided by
  27   * the file mime.types in the includes directory.
  28   *
  29   * This list concatenated with mime.types is used to create a MIME <-> ext
  30   * map. Each line contains a MIME type followed by a space separated list of
  31   * extensions. If multiple extensions for a single MIME type exist or if
  32   * multiple MIME types exist for a single extension then in most cases
  33   * MediaWiki assumes that the first extension following the MIME type is the
  34   * canonical extension, and the first time a MIME type appears for a certain
  35   * extension is considered the canonical MIME type.
  36   *
  37   * (Note that appending $wgMimeTypeFile to the end of MM_WELL_KNOWN_MIME_TYPES
  38   * sucks because you can't redefine canonical types. This could be fixed by
  39   * appending MM_WELL_KNOWN_MIME_TYPES behind $wgMimeTypeFile, but who knows
  40   * what will break? In practice this probably isn't a problem anyway -- Bryan)
  41   */
  42  define( 'MM_WELL_KNOWN_MIME_TYPES', <<<END_STRING
  43  application/ogg ogx ogg ogm ogv oga spx
  44  application/pdf pdf
  45  application/vnd.oasis.opendocument.chart odc
  46  application/vnd.oasis.opendocument.chart-template otc
  47  application/vnd.oasis.opendocument.database odb
  48  application/vnd.oasis.opendocument.formula odf
  49  application/vnd.oasis.opendocument.formula-template otf
  50  application/vnd.oasis.opendocument.graphics odg
  51  application/vnd.oasis.opendocument.graphics-template otg
  52  application/vnd.oasis.opendocument.image odi
  53  application/vnd.oasis.opendocument.image-template oti
  54  application/vnd.oasis.opendocument.presentation odp
  55  application/vnd.oasis.opendocument.presentation-template otp
  56  application/vnd.oasis.opendocument.spreadsheet ods
  57  application/vnd.oasis.opendocument.spreadsheet-template ots
  58  application/vnd.oasis.opendocument.text odt
  59  application/vnd.oasis.opendocument.text-master otm
  60  application/vnd.oasis.opendocument.text-template ott
  61  application/vnd.oasis.opendocument.text-web oth
  62  application/x-javascript js
  63  application/x-shockwave-flash swf
  64  audio/midi mid midi kar
  65  audio/mpeg mpga mpa mp2 mp3
  66  audio/x-aiff aif aiff aifc
  67  audio/x-wav wav
  68  audio/ogg oga spx ogg
  69  image/x-bmp bmp
  70  image/gif gif
  71  image/jpeg jpeg jpg jpe
  72  image/png png
  73  image/svg+xml svg
  74  image/svg svg
  75  image/tiff tiff tif
  76  image/vnd.djvu djvu
  77  image/x.djvu djvu
  78  image/x-djvu djvu
  79  image/x-portable-pixmap ppm
  80  image/x-xcf xcf
  81  text/plain txt
  82  text/html html htm
  83  video/ogg ogv ogm ogg
  84  video/mpeg mpg mpeg
  85  END_STRING
  86  );
  87  
  88  /**
  89   * Defines a set of well known MIME info entries
  90   * This is used as a fallback to mime.info files.
  91   * An extensive list of well known MIME types is provided by
  92   * the file mime.info in the includes directory.
  93   */
  94  define( 'MM_WELL_KNOWN_MIME_INFO', <<<END_STRING
  95  application/pdf [OFFICE]
  96  application/vnd.oasis.opendocument.chart [OFFICE]
  97  application/vnd.oasis.opendocument.chart-template [OFFICE]
  98  application/vnd.oasis.opendocument.database [OFFICE]
  99  application/vnd.oasis.opendocument.formula [OFFICE]
 100  application/vnd.oasis.opendocument.formula-template [OFFICE]
 101  application/vnd.oasis.opendocument.graphics [OFFICE]
 102  application/vnd.oasis.opendocument.graphics-template [OFFICE]
 103  application/vnd.oasis.opendocument.image [OFFICE]
 104  application/vnd.oasis.opendocument.image-template [OFFICE]
 105  application/vnd.oasis.opendocument.presentation [OFFICE]
 106  application/vnd.oasis.opendocument.presentation-template [OFFICE]
 107  application/vnd.oasis.opendocument.spreadsheet [OFFICE]
 108  application/vnd.oasis.opendocument.spreadsheet-template [OFFICE]
 109  application/vnd.oasis.opendocument.text [OFFICE]
 110  application/vnd.oasis.opendocument.text-template [OFFICE]
 111  application/vnd.oasis.opendocument.text-master [OFFICE]
 112  application/vnd.oasis.opendocument.text-web [OFFICE]
 113  text/javascript application/x-javascript [EXECUTABLE]
 114  application/x-shockwave-flash [MULTIMEDIA]
 115  audio/midi [AUDIO]
 116  audio/x-aiff [AUDIO]
 117  audio/x-wav [AUDIO]
 118  audio/mp3 audio/mpeg [AUDIO]
 119  application/ogg audio/ogg video/ogg [MULTIMEDIA]
 120  image/x-bmp image/x-ms-bmp image/bmp [BITMAP]
 121  image/gif [BITMAP]
 122  image/jpeg [BITMAP]
 123  image/png [BITMAP]
 124  image/svg+xml [DRAWING]
 125  image/tiff [BITMAP]
 126  image/vnd.djvu [BITMAP]
 127  image/x-xcf [BITMAP]
 128  image/x-portable-pixmap [BITMAP]
 129  text/plain [TEXT]
 130  text/html [TEXT]
 131  video/ogg [VIDEO]
 132  video/mpeg [VIDEO]
 133  unknown/unknown application/octet-stream application/x-empty [UNKNOWN]
 134  END_STRING
 135  );
 136  
 137  /**
 138   * Implements functions related to MIME types such as detection and mapping to
 139   * file extension.
 140   *
 141   * Instances of this class are stateless, there only needs to be one global instance
 142   * of MimeMagic. Please use MimeMagic::singleton() to get that instance.
 143   */
 144  class MimeMagic {
 145      /**
 146       * @var array Mapping of media types to arrays of MIME types.
 147       * This is used by findMediaType and getMediaType, respectively
 148       */
 149      protected $mMediaTypes = null;
 150  
 151      /** @var array Map of MIME type aliases
 152       */
 153      protected $mMimeTypeAliases = null;
 154  
 155      /** @var array Map of MIME types to file extensions (as a space separated list)
 156       */
 157      protected $mMimeToExt = null;
 158  
 159      /** @var array Map of file extensions types to MIME types (as a space separated list)
 160       */
 161      public $mExtToMime = null;
 162  
 163      /** @var IEContentAnalyzer
 164       */
 165      protected $mIEAnalyzer;
 166  
 167      /** @var string Extra MIME types, set for example by media handling extensions
 168       */
 169      private $mExtraTypes = '';
 170  
 171      /** @var string Extra MIME info, set for example by media handling extensions
 172       */
 173      private $mExtraInfo = '';
 174  
 175      /** @var Config */
 176      private $mConfig;
 177  
 178      /** @var MimeMagic The singleton instance
 179       */
 180      private static $instance = null;
 181  
 182      /** Initializes the MimeMagic object. This is called by MimeMagic::singleton().
 183       *
 184       * This constructor parses the mime.types and mime.info files and build internal mappings.
 185       *
 186       * @todo Make this constructor private once everything uses the singleton instance
 187       * @param Config $config
 188       */
 189  	function __construct( Config $config = null ) {
 190          if ( !$config ) {
 191              wfDebug( __METHOD__ . ' called with no Config instance passed to it' );
 192              $config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
 193          }
 194          $this->mConfig = $config;
 195  
 196          /**
 197           *   --- load mime.types ---
 198           */
 199  
 200          global $IP;
 201  
 202          # Allow media handling extensions adding MIME-types and MIME-info
 203          wfRunHooks( 'MimeMagicInit', array( $this ) );
 204  
 205          $types = MM_WELL_KNOWN_MIME_TYPES;
 206  
 207          $mimeTypeFile = $this->mConfig->get( 'MimeTypeFile' );
 208          if ( $mimeTypeFile == 'includes/mime.types' ) {
 209              $mimeTypeFile = "$IP/$mimeTypeFile";
 210          }
 211  
 212          if ( $mimeTypeFile ) {
 213              if ( is_file( $mimeTypeFile ) and is_readable( $mimeTypeFile ) ) {
 214                  wfDebug( __METHOD__ . ": loading mime types from $mimeTypeFile\n" );
 215                  $types .= "\n";
 216                  $types .= file_get_contents( $mimeTypeFile );
 217              } else {
 218                  wfDebug( __METHOD__ . ": can't load mime types from $mimeTypeFile\n" );
 219              }
 220          } else {
 221              wfDebug( __METHOD__ . ": no mime types file defined, using build-ins only.\n" );
 222          }
 223  
 224          $types .= "\n" . $this->mExtraTypes;
 225  
 226          $types = str_replace( array( "\r\n", "\n\r", "\n\n", "\r\r", "\r" ), "\n", $types );
 227          $types = str_replace( "\t", " ", $types );
 228  
 229          $this->mMimeToExt = array();
 230          $this->mExtToMime = array();
 231  
 232          $lines = explode( "\n", $types );
 233          foreach ( $lines as $s ) {
 234              $s = trim( $s );
 235              if ( empty( $s ) ) {
 236                  continue;
 237              }
 238              if ( strpos( $s, '#' ) === 0 ) {
 239                  continue;
 240              }
 241  
 242              $s = strtolower( $s );
 243              $i = strpos( $s, ' ' );
 244  
 245              if ( $i === false ) {
 246                  continue;
 247              }
 248  
 249              $mime = substr( $s, 0, $i );
 250              $ext = trim( substr( $s, $i + 1 ) );
 251  
 252              if ( empty( $ext ) ) {
 253                  continue;
 254              }
 255  
 256              if ( !empty( $this->mMimeToExt[$mime] ) ) {
 257                  $this->mMimeToExt[$mime] .= ' ' . $ext;
 258              } else {
 259                  $this->mMimeToExt[$mime] = $ext;
 260              }
 261  
 262              $extensions = explode( ' ', $ext );
 263  
 264              foreach ( $extensions as $e ) {
 265                  $e = trim( $e );
 266                  if ( empty( $e ) ) {
 267                      continue;
 268                  }
 269  
 270                  if ( !empty( $this->mExtToMime[$e] ) ) {
 271                      $this->mExtToMime[$e] .= ' ' . $mime;
 272                  } else {
 273                      $this->mExtToMime[$e] = $mime;
 274                  }
 275              }
 276          }
 277  
 278          /**
 279           *   --- load mime.info ---
 280           */
 281  
 282          $mimeInfoFile = $this->mConfig->get( 'MimeInfoFile' );
 283          if ( $mimeInfoFile == 'includes/mime.info' ) {
 284              $mimeInfoFile = "$IP/$mimeInfoFile";
 285          }
 286  
 287          $info = MM_WELL_KNOWN_MIME_INFO;
 288  
 289          if ( $mimeInfoFile ) {
 290              if ( is_file( $mimeInfoFile ) and is_readable( $mimeInfoFile ) ) {
 291                  wfDebug( __METHOD__ . ": loading mime info from $mimeInfoFile\n" );
 292                  $info .= "\n";
 293                  $info .= file_get_contents( $mimeInfoFile );
 294              } else {
 295                  wfDebug( __METHOD__ . ": can't load mime info from $mimeInfoFile\n" );
 296              }
 297          } else {
 298              wfDebug( __METHOD__ . ": no mime info file defined, using build-ins only.\n" );
 299          }
 300  
 301          $info .= "\n" . $this->mExtraInfo;
 302  
 303          $info = str_replace( array( "\r\n", "\n\r", "\n\n", "\r\r", "\r" ), "\n", $info );
 304          $info = str_replace( "\t", " ", $info );
 305  
 306          $this->mMimeTypeAliases = array();
 307          $this->mMediaTypes = array();
 308  
 309          $lines = explode( "\n", $info );
 310          foreach ( $lines as $s ) {
 311              $s = trim( $s );
 312              if ( empty( $s ) ) {
 313                  continue;
 314              }
 315              if ( strpos( $s, '#' ) === 0 ) {
 316                  continue;
 317              }
 318  
 319              $s = strtolower( $s );
 320              $i = strpos( $s, ' ' );
 321  
 322              if ( $i === false ) {
 323                  continue;
 324              }
 325  
 326              #print "processing MIME INFO line $s<br>";
 327  
 328              $match = array();
 329              if ( preg_match( '!\[\s*(\w+)\s*\]!', $s, $match ) ) {
 330                  $s = preg_replace( '!\[\s*(\w+)\s*\]!', '', $s );
 331                  $mtype = trim( strtoupper( $match[1] ) );
 332              } else {
 333                  $mtype = MEDIATYPE_UNKNOWN;
 334              }
 335  
 336              $m = explode( ' ', $s );
 337  
 338              if ( !isset( $this->mMediaTypes[$mtype] ) ) {
 339                  $this->mMediaTypes[$mtype] = array();
 340              }
 341  
 342              foreach ( $m as $mime ) {
 343                  $mime = trim( $mime );
 344                  if ( empty( $mime ) ) {
 345                      continue;
 346                  }
 347  
 348                  $this->mMediaTypes[$mtype][] = $mime;
 349              }
 350  
 351              if ( count( $m ) > 1 ) {
 352                  $main = $m[0];
 353                  $mCount = count( $m );
 354                  for ( $i = 1; $i < $mCount; $i += 1 ) {
 355                      $mime = $m[$i];
 356                      $this->mMimeTypeAliases[$mime] = $main;
 357                  }
 358              }
 359          }
 360      }
 361  
 362      /**
 363       * Get an instance of this class
 364       * @return MimeMagic
 365       */
 366  	public static function singleton() {
 367          if ( self::$instance === null ) {
 368              self::$instance = new MimeMagic(
 369                  ConfigFactory::getDefaultInstance()->makeConfig( 'main' )
 370              );
 371          }
 372          return self::$instance;
 373      }
 374  
 375      /**
 376       * Adds to the list mapping MIME to file extensions.
 377       * As an extension author, you are encouraged to submit patches to
 378       * MediaWiki's core to add new MIME types to mime.types.
 379       * @param string $types
 380       */
 381  	public function addExtraTypes( $types ) {
 382          $this->mExtraTypes .= "\n" . $types;
 383      }
 384  
 385      /**
 386       * Adds to the list mapping MIME to media type.
 387       * As an extension author, you are encouraged to submit patches to
 388       * MediaWiki's core to add new MIME info to mime.info.
 389       * @param string $info
 390       */
 391  	public function addExtraInfo( $info ) {
 392          $this->mExtraInfo .= "\n" . $info;
 393      }
 394  
 395      /**
 396       * Returns a list of file extensions for a given MIME type as a space
 397       * separated string or null if the MIME type was unrecognized. Resolves
 398       * MIME type aliases.
 399       *
 400       * @param string $mime
 401       * @return string|null
 402       */
 403  	public function getExtensionsForType( $mime ) {
 404          $mime = strtolower( $mime );
 405  
 406          // Check the mime-to-ext map
 407          if ( isset( $this->mMimeToExt[$mime] ) ) {
 408              return $this->mMimeToExt[$mime];
 409          }
 410  
 411          // Resolve the MIME type to the canonical type
 412          if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
 413              $mime = $this->mMimeTypeAliases[$mime];
 414              if ( isset( $this->mMimeToExt[$mime] ) ) {
 415                  return $this->mMimeToExt[$mime];
 416              }
 417          }
 418  
 419          return null;
 420      }
 421  
 422      /**
 423       * Returns a list of MIME types for a given file extension as a space
 424       * separated string or null if the extension was unrecognized.
 425       *
 426       * @param string $ext
 427       * @return string|null
 428       */
 429  	public function getTypesForExtension( $ext ) {
 430          $ext = strtolower( $ext );
 431  
 432          $r = isset( $this->mExtToMime[$ext] ) ? $this->mExtToMime[$ext] : null;
 433          return $r;
 434      }
 435  
 436      /**
 437       * Returns a single MIME type for a given file extension or null if unknown.
 438       * This is always the first type from the list returned by getTypesForExtension($ext).
 439       *
 440       * @param string $ext
 441       * @return string|null
 442       */
 443  	public function guessTypesForExtension( $ext ) {
 444          $m = $this->getTypesForExtension( $ext );
 445          if ( is_null( $m ) ) {
 446              return null;
 447          }
 448  
 449          // TODO: Check if this is needed; strtok( $m, ' ' ) should be sufficient
 450          $m = trim( $m );
 451          $m = preg_replace( '/\s.*$/', '', $m );
 452  
 453          return $m;
 454      }
 455  
 456      /**
 457       * Tests if the extension matches the given MIME type. Returns true if a
 458       * match was found, null if the MIME type is unknown, and false if the
 459       * MIME type is known but no matches where found.
 460       *
 461       * @param string $extension
 462       * @param string $mime
 463       * @return bool|null
 464       */
 465  	public function isMatchingExtension( $extension, $mime ) {
 466          $ext = $this->getExtensionsForType( $mime );
 467  
 468          if ( !$ext ) {
 469              return null; // Unknown MIME type
 470          }
 471  
 472          $ext = explode( ' ', $ext );
 473  
 474          $extension = strtolower( $extension );
 475          return in_array( $extension, $ext );
 476      }
 477  
 478      /**
 479       * Returns true if the MIME type is known to represent an image format
 480       * supported by the PHP GD library.
 481       *
 482       * @param string $mime
 483       *
 484       * @return bool
 485       */
 486  	public function isPHPImageType( $mime ) {
 487          // As defined by imagegetsize and image_type_to_mime
 488          static $types = array(
 489              'image/gif', 'image/jpeg', 'image/png',
 490              'image/x-bmp', 'image/xbm', 'image/tiff',
 491              'image/jp2', 'image/jpeg2000', 'image/iff',
 492              'image/xbm', 'image/x-xbitmap',
 493              'image/vnd.wap.wbmp', 'image/vnd.xiff',
 494              'image/x-photoshop',
 495              'application/x-shockwave-flash',
 496          );
 497  
 498          return in_array( $mime, $types );
 499      }
 500  
 501      /**
 502       * Returns true if the extension represents a type which can
 503       * be reliably detected from its content. Use this to determine
 504       * whether strict content checks should be applied to reject
 505       * invalid uploads; if we can't identify the type we won't
 506       * be able to say if it's invalid.
 507       *
 508       * @todo Be more accurate when using fancy MIME detector plugins;
 509       *       right now this is the bare minimum getimagesize() list.
 510       * @param string $extension
 511       * @return bool
 512       */
 513  	function isRecognizableExtension( $extension ) {
 514          static $types = array(
 515              // Types recognized by getimagesize()
 516              'gif', 'jpeg', 'jpg', 'png', 'swf', 'psd',
 517              'bmp', 'tiff', 'tif', 'jpc', 'jp2',
 518              'jpx', 'jb2', 'swc', 'iff', 'wbmp',
 519              'xbm',
 520  
 521              // Formats we recognize magic numbers for
 522              'djvu', 'ogx', 'ogg', 'ogv', 'oga', 'spx',
 523              'mid', 'pdf', 'wmf', 'xcf', 'webm', 'mkv', 'mka',
 524              'webp',
 525  
 526              // XML formats we sure hope we recognize reliably
 527              'svg',
 528          );
 529          return in_array( strtolower( $extension ), $types );
 530      }
 531  
 532      /**
 533       * Improves a MIME type using the file extension. Some file formats are very generic,
 534       * so their MIME type is not very meaningful. A more useful MIME type can be derived
 535       * by looking at the file extension. Typically, this method would be called on the
 536       * result of guessMimeType().
 537       *
 538       * @param string $mime The MIME type, typically guessed from a file's content.
 539       * @param string $ext The file extension, as taken from the file name
 540       *
 541       * @return string The MIME type
 542       */
 543  	public function improveTypeFromExtension( $mime, $ext ) {
 544          if ( $mime === 'unknown/unknown' ) {
 545              if ( $this->isRecognizableExtension( $ext ) ) {
 546                  wfDebug( __METHOD__ . ': refusing to guess mime type for .' .
 547                      "$ext file, we should have recognized it\n" );
 548              } else {
 549                  // Not something we can detect, so simply
 550                  // trust the file extension
 551                  $mime = $this->guessTypesForExtension( $ext );
 552              }
 553          } elseif ( $mime === 'application/x-opc+zip' ) {
 554              if ( $this->isMatchingExtension( $ext, $mime ) ) {
 555                  // A known file extension for an OPC file,
 556                  // find the proper MIME type for that file extension
 557                  $mime = $this->guessTypesForExtension( $ext );
 558              } else {
 559                  wfDebug( __METHOD__ . ": refusing to guess better type for $mime file, " .
 560                      ".$ext is not a known OPC extension.\n" );
 561                  $mime = 'application/zip';
 562              }
 563          } elseif ( $mime === 'text/plain' && $this->findMediaType( ".$ext" ) === MEDIATYPE_TEXT ) {
 564              // Textual types are sometimes not recognized properly.
 565              // If detected as text/plain, and has an extension which is textual
 566              // improve to the extension's type. For example, csv and json are often
 567              // misdetected as text/plain.
 568              $mime = $this->guessTypesForExtension( $ext );
 569          }
 570  
 571          # Media handling extensions can improve the MIME detected
 572          wfRunHooks( 'MimeMagicImproveFromExtension', array( $this, $ext, &$mime ) );
 573  
 574          if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
 575              $mime = $this->mMimeTypeAliases[$mime];
 576          }
 577  
 578          wfDebug( __METHOD__ . ": improved mime type for .$ext: $mime\n" );
 579          return $mime;
 580      }
 581  
 582      /**
 583       * MIME type detection. This uses detectMimeType to detect the MIME type
 584       * of the file, but applies additional checks to determine some well known
 585       * file formats that may be missed or misinterpreted by the default MIME
 586       * detection (namely XML based formats like XHTML or SVG, as well as ZIP
 587       * based formats like OPC/ODF files).
 588       *
 589       * @param string $file The file to check
 590       * @param string|bool $ext The file extension, or true (default) to extract it from the filename.
 591       *   Set it to false to ignore the extension. DEPRECATED! Set to false, use
 592       *   improveTypeFromExtension($mime, $ext) later to improve MIME type.
 593       *
 594       * @return string The MIME type of $file
 595       */
 596  	public function guessMimeType( $file, $ext = true ) {
 597          if ( $ext ) { // TODO: make $ext default to false. Or better, remove it.
 598              wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. " .
 599                  "Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
 600          }
 601  
 602          $mime = $this->doGuessMimeType( $file, $ext );
 603  
 604          if ( !$mime ) {
 605              wfDebug( __METHOD__ . ": internal type detection failed for $file (.$ext)...\n" );
 606              $mime = $this->detectMimeType( $file, $ext );
 607          }
 608  
 609          if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
 610              $mime = $this->mMimeTypeAliases[$mime];
 611          }
 612  
 613          wfDebug( __METHOD__ . ": guessed mime type of $file: $mime\n" );
 614          return $mime;
 615      }
 616  
 617      /**
 618       * Guess the MIME type from the file contents.
 619       *
 620       * @param string $file
 621       * @param mixed $ext
 622       * @return bool|string
 623       * @throws MWException
 624       */
 625  	private function doGuessMimeType( $file, $ext ) { // TODO: remove $ext param
 626          // Read a chunk of the file
 627          wfSuppressWarnings();
 628          $f = fopen( $file, 'rb' );
 629          wfRestoreWarnings();
 630  
 631          if ( !$f ) {
 632              return 'unknown/unknown';
 633          }
 634  
 635          $fsize = filesize( $file );
 636          if ( $fsize === false ) {
 637              return 'unknown/unknown';
 638          }
 639  
 640          $head = fread( $f, 1024 );
 641          $tailLength = min( 65558, $fsize ); // 65558 = maximum size of a zip EOCDR
 642          if ( fseek( $f, -1 * $tailLength, SEEK_END ) === -1 ) {
 643              throw new MWException(
 644                  "Seeking $tailLength bytes from EOF failed in " . __METHOD__ );
 645          }
 646          $tail = fread( $f, $tailLength );
 647          fclose( $f );
 648  
 649          wfDebug( __METHOD__ . ": analyzing head and tail of $file for magic numbers.\n" );
 650  
 651          // Hardcode a few magic number checks...
 652          $headers = array(
 653              // Multimedia...
 654              'MThd'             => 'audio/midi',
 655              'OggS'             => 'application/ogg',
 656  
 657              // Image formats...
 658              // Note that WMF may have a bare header, no magic number.
 659              "\x01\x00\x09\x00" => 'application/x-msmetafile', // Possibly prone to false positives?
 660              "\xd7\xcd\xc6\x9a" => 'application/x-msmetafile',
 661              '%PDF'             => 'application/pdf',
 662              'gimp xcf'         => 'image/x-xcf',
 663  
 664              // Some forbidden fruit...
 665              'MZ'               => 'application/octet-stream', // DOS/Windows executable
 666              "\xca\xfe\xba\xbe" => 'application/octet-stream', // Mach-O binary
 667              "\x7fELF"          => 'application/octet-stream', // ELF binary
 668          );
 669  
 670          foreach ( $headers as $magic => $candidate ) {
 671              if ( strncmp( $head, $magic, strlen( $magic ) ) == 0 ) {
 672                  wfDebug( __METHOD__ . ": magic header in $file recognized as $candidate\n" );
 673                  return $candidate;
 674              }
 675          }
 676  
 677          /* Look for WebM and Matroska files */
 678          if ( strncmp( $head, pack( "C4", 0x1a, 0x45, 0xdf, 0xa3 ), 4 ) == 0 ) {
 679              $doctype = strpos( $head, "\x42\x82" );
 680              if ( $doctype ) {
 681                  // Next byte is datasize, then data (sizes larger than 1 byte are very stupid muxers)
 682                  $data = substr( $head, $doctype + 3, 8 );
 683                  if ( strncmp( $data, "matroska", 8 ) == 0 ) {
 684                      wfDebug( __METHOD__ . ": recognized file as video/x-matroska\n" );
 685                      return "video/x-matroska";
 686                  } elseif ( strncmp( $data, "webm", 4 ) == 0 ) {
 687                      wfDebug( __METHOD__ . ": recognized file as video/webm\n" );
 688                      return "video/webm";
 689                  }
 690              }
 691              wfDebug( __METHOD__ . ": unknown EBML file\n" );
 692              return "unknown/unknown";
 693          }
 694  
 695          /* Look for WebP */
 696          if ( strncmp( $head, "RIFF", 4 ) == 0 && strncmp( substr( $head, 8, 8 ), "WEBPVP8 ", 8 ) == 0 ) {
 697              wfDebug( __METHOD__ . ": recognized file as image/webp\n" );
 698              return "image/webp";
 699          }
 700  
 701          /**
 702           * Look for PHP.  Check for this before HTML/XML...  Warning: this is a
 703           * heuristic, and won't match a file with a lot of non-PHP before.  It
 704           * will also match text files which could be PHP. :)
 705           *
 706           * @todo FIXME: For this reason, the check is probably useless -- an attacker
 707           * could almost certainly just pad the file with a lot of nonsense to
 708           * circumvent the check in any case where it would be a security
 709           * problem.  On the other hand, it causes harmful false positives (bug
 710           * 16583).  The heuristic has been cut down to exclude three-character
 711           * strings like "<? ", but should it be axed completely?
 712           */
 713          if ( ( strpos( $head, '<?php' ) !== false ) ||
 714              ( strpos( $head, "<\x00?\x00p\x00h\x00p" ) !== false ) ||
 715              ( strpos( $head, "<\x00?\x00 " ) !== false ) ||
 716              ( strpos( $head, "<\x00?\x00\n" ) !== false ) ||
 717              ( strpos( $head, "<\x00?\x00\t" ) !== false ) ||
 718              ( strpos( $head, "<\x00?\x00=" ) !== false ) ) {
 719  
 720              wfDebug( __METHOD__ . ": recognized $file as application/x-php\n" );
 721              return 'application/x-php';
 722          }
 723  
 724          /**
 725           * look for XML formats (XHTML and SVG)
 726           */
 727          $xml = new XmlTypeCheck( $file );
 728          if ( $xml->wellFormed ) {
 729              $xmlMimeTypes = $this->mConfig->get( 'XMLMimeTypes' );
 730              if ( isset( $xmlMimeTypes[$xml->getRootElement()] ) ) {
 731                  return $xmlMimeTypes[$xml->getRootElement()];
 732              } else {
 733                  return 'application/xml';
 734              }
 735          }
 736  
 737          /**
 738           * look for shell scripts
 739           */
 740          $script_type = null;
 741  
 742          # detect by shebang
 743          if ( substr( $head, 0, 2 ) == "#!" ) {
 744              $script_type = "ASCII";
 745          } elseif ( substr( $head, 0, 5 ) == "\xef\xbb\xbf#!" ) {
 746              $script_type = "UTF-8";
 747          } elseif ( substr( $head, 0, 7 ) == "\xfe\xff\x00#\x00!" ) {
 748              $script_type = "UTF-16BE";
 749          } elseif ( substr( $head, 0, 7 ) == "\xff\xfe#\x00!" ) {
 750              $script_type = "UTF-16LE";
 751          }
 752  
 753          if ( $script_type ) {
 754              if ( $script_type !== "UTF-8" && $script_type !== "ASCII" ) {
 755                  // Quick and dirty fold down to ASCII!
 756                  $pack = array( 'UTF-16BE' => 'n*', 'UTF-16LE' => 'v*' );
 757                  $chars = unpack( $pack[$script_type], substr( $head, 2 ) );
 758                  $head = '';
 759                  foreach ( $chars as $codepoint ) {
 760                      if ( $codepoint < 128 ) {
 761                          $head .= chr( $codepoint );
 762                      } else {
 763                          $head .= '?';
 764                      }
 765                  }
 766              }
 767  
 768              $match = array();
 769  
 770              if ( preg_match( '%/?([^\s]+/)(\w+)%', $head, $match ) ) {
 771                  $mime = "application/x-{$match[2]}";
 772                  wfDebug( __METHOD__ . ": shell script recognized as $mime\n" );
 773                  return $mime;
 774              }
 775          }
 776  
 777          // Check for ZIP variants (before getimagesize)
 778          if ( strpos( $tail, "PK\x05\x06" ) !== false ) {
 779              wfDebug( __METHOD__ . ": ZIP header present in $file\n" );
 780              return $this->detectZipType( $head, $tail, $ext );
 781          }
 782  
 783          wfSuppressWarnings();
 784          $gis = getimagesize( $file );
 785          wfRestoreWarnings();
 786  
 787          if ( $gis && isset( $gis['mime'] ) ) {
 788              $mime = $gis['mime'];
 789              wfDebug( __METHOD__ . ": getimagesize detected $file as $mime\n" );
 790              return $mime;
 791          }
 792  
 793          // Also test DjVu
 794          $deja = new DjVuImage( $file );
 795          if ( $deja->isValid() ) {
 796              wfDebug( __METHOD__ . ": detected $file as image/vnd.djvu\n" );
 797              return 'image/vnd.djvu';
 798          }
 799  
 800          # Media handling extensions can guess the MIME by content
 801          # It's intentionally here so that if core is wrong about a type (false positive),
 802          # people will hopefully nag and submit patches :)
 803          $mime = false;
 804          # Some strings by reference for performance - assuming well-behaved hooks
 805          wfRunHooks(
 806              'MimeMagicGuessFromContent',
 807              array( $this, &$head, &$tail, $file, &$mime )
 808          );
 809  
 810          return $mime;
 811      }
 812  
 813      /**
 814       * Detect application-specific file type of a given ZIP file from its
 815       * header data.  Currently works for OpenDocument and OpenXML types...
 816       * If can't tell, returns 'application/zip'.
 817       *
 818       * @param string $header Some reasonably-sized chunk of file header
 819       * @param string|null $tail The tail of the file
 820       * @param string|bool $ext The file extension, or true to extract it from the filename.
 821       *   Set it to false (default) to ignore the extension. DEPRECATED! Set to false,
 822       *   use improveTypeFromExtension($mime, $ext) later to improve MIME type.
 823       *
 824       * @return string
 825       */
 826  	function detectZipType( $header, $tail = null, $ext = false ) {
 827          if ( $ext ) { # TODO: remove $ext param
 828              wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. " .
 829                  "Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
 830          }
 831  
 832          $mime = 'application/zip';
 833          $opendocTypes = array(
 834              'chart-template',
 835              'chart',
 836              'formula-template',
 837              'formula',
 838              'graphics-template',
 839              'graphics',
 840              'image-template',
 841              'image',
 842              'presentation-template',
 843              'presentation',
 844              'spreadsheet-template',
 845              'spreadsheet',
 846              'text-template',
 847              'text-master',
 848              'text-web',
 849              'text' );
 850  
 851          // http://lists.oasis-open.org/archives/office/200505/msg00006.html
 852          $types = '(?:' . implode( '|', $opendocTypes ) . ')';
 853          $opendocRegex = "/^mimetype(application\/vnd\.oasis\.opendocument\.$types)/";
 854  
 855          $openxmlRegex = "/^\[Content_Types\].xml/";
 856  
 857          if ( preg_match( $opendocRegex, substr( $header, 30 ), $matches ) ) {
 858              $mime = $matches[1];
 859              wfDebug( __METHOD__ . ": detected $mime from ZIP archive\n" );
 860          } elseif ( preg_match( $openxmlRegex, substr( $header, 30 ) ) ) {
 861              $mime = "application/x-opc+zip";
 862              # TODO: remove the block below, as soon as improveTypeFromExtension is used everywhere
 863              if ( $ext !== true && $ext !== false ) {
 864                  /** This is the mode used by getPropsFromPath
 865                   * These MIME's are stored in the database, where we don't really want
 866                   * x-opc+zip, because we use it only for internal purposes
 867                   */
 868                  if ( $this->isMatchingExtension( $ext, $mime ) ) {
 869                      /* A known file extension for an OPC file,
 870                       * find the proper mime type for that file extension
 871                       */
 872                      $mime = $this->guessTypesForExtension( $ext );
 873                  } else {
 874                      $mime = "application/zip";
 875                  }
 876              }
 877              wfDebug( __METHOD__ . ": detected an Open Packaging Conventions archive: $mime\n" );
 878          } elseif ( substr( $header, 0, 8 ) == "\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1" &&
 879                  ( $headerpos = strpos( $tail, "PK\x03\x04" ) ) !== false &&
 880                  preg_match( $openxmlRegex, substr( $tail, $headerpos + 30 ) ) ) {
 881              if ( substr( $header, 512, 4 ) == "\xEC\xA5\xC1\x00" ) {
 882                  $mime = "application/msword";
 883              }
 884              switch ( substr( $header, 512, 6 ) ) {
 885                  case "\xEC\xA5\xC1\x00\x0E\x00":
 886                  case "\xEC\xA5\xC1\x00\x1C\x00":
 887                  case "\xEC\xA5\xC1\x00\x43\x00":
 888                      $mime = "application/vnd.ms-powerpoint";
 889                      break;
 890                  case "\xFD\xFF\xFF\xFF\x10\x00":
 891                  case "\xFD\xFF\xFF\xFF\x1F\x00":
 892                  case "\xFD\xFF\xFF\xFF\x22\x00":
 893                  case "\xFD\xFF\xFF\xFF\x23\x00":
 894                  case "\xFD\xFF\xFF\xFF\x28\x00":
 895                  case "\xFD\xFF\xFF\xFF\x29\x00":
 896                  case "\xFD\xFF\xFF\xFF\x10\x02":
 897                  case "\xFD\xFF\xFF\xFF\x1F\x02":
 898                  case "\xFD\xFF\xFF\xFF\x22\x02":
 899                  case "\xFD\xFF\xFF\xFF\x23\x02":
 900                  case "\xFD\xFF\xFF\xFF\x28\x02":
 901                  case "\xFD\xFF\xFF\xFF\x29\x02":
 902                      $mime = "application/vnd.msexcel";
 903                      break;
 904              }
 905  
 906              wfDebug( __METHOD__ . ": detected a MS Office document with OPC trailer\n" );
 907          } else {
 908              wfDebug( __METHOD__ . ": unable to identify type of ZIP archive\n" );
 909          }
 910          return $mime;
 911      }
 912  
 913      /**
 914       * Internal MIME type detection. Detection is done using an external
 915       * program, if $wgMimeDetectorCommand is set. Otherwise, the fileinfo
 916       * extension is tried if it is available. If detection fails and $ext
 917       * is not false, the MIME type is guessed from the file extension,
 918       * using guessTypesForExtension.
 919       *
 920       * If the MIME type is still unknown, getimagesize is used to detect the
 921       * MIME type if the file is an image. If no MIME type can be determined,
 922       * this function returns 'unknown/unknown'.
 923       *
 924       * @param string $file The file to check
 925       * @param string|bool $ext The file extension, or true (default) to extract it from the filename.
 926       *   Set it to false to ignore the extension. DEPRECATED! Set to false, use
 927       *   improveTypeFromExtension($mime, $ext) later to improve MIME type.
 928       *
 929       * @return string The MIME type of $file
 930       */
 931  	private function detectMimeType( $file, $ext = true ) {
 932          /** @todo Make $ext default to false. Or better, remove it. */
 933          if ( $ext ) {
 934              wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. "
 935                  . "Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
 936          }
 937  
 938          $mimeDetectorCommand = $this->mConfig->get( 'MimeDetectorCommand' );
 939          $m = null;
 940          if ( $mimeDetectorCommand ) {
 941              $args = wfEscapeShellArg( $file );
 942              $m = wfShellExec( "$mimeDetectorCommand $args" );
 943          } elseif ( function_exists( "finfo_open" ) && function_exists( "finfo_file" ) ) {
 944              $mime_magic_resource = finfo_open( FILEINFO_MIME );
 945  
 946              if ( $mime_magic_resource ) {
 947                  $m = finfo_file( $mime_magic_resource, $file );
 948                  finfo_close( $mime_magic_resource );
 949              } else {
 950                  wfDebug( __METHOD__ . ": finfo_open failed on " . FILEINFO_MIME . "!\n" );
 951              }
 952          } else {
 953              wfDebug( __METHOD__ . ": no magic mime detector found!\n" );
 954          }
 955  
 956          if ( $m ) {
 957              # normalize
 958              $m = preg_replace( '![;, ].*$!', '', $m ); #strip charset, etc
 959              $m = trim( $m );
 960              $m = strtolower( $m );
 961  
 962              if ( strpos( $m, 'unknown' ) !== false ) {
 963                  $m = null;
 964              } else {
 965                  wfDebug( __METHOD__ . ": magic mime type of $file: $m\n" );
 966                  return $m;
 967              }
 968          }
 969  
 970          // If desired, look at extension as a fallback.
 971          if ( $ext === true ) {
 972              $i = strrpos( $file, '.' );
 973              $ext = strtolower( $i ? substr( $file, $i + 1 ) : '' );
 974          }
 975          if ( $ext ) {
 976              if ( $this->isRecognizableExtension( $ext ) ) {
 977                  wfDebug( __METHOD__ . ": refusing to guess mime type for .$ext file, "
 978                      . "we should have recognized it\n" );
 979              } else {
 980                  $m = $this->guessTypesForExtension( $ext );
 981                  if ( $m ) {
 982                      wfDebug( __METHOD__ . ": extension mime type of $file: $m\n" );
 983                      return $m;
 984                  }
 985              }
 986          }
 987  
 988          // Unknown type
 989          wfDebug( __METHOD__ . ": failed to guess mime type for $file!\n" );
 990          return 'unknown/unknown';
 991      }
 992  
 993      /**
 994       * Determine the media type code for a file, using its MIME type, name and
 995       * possibly its contents.
 996       *
 997       * This function relies on the findMediaType(), mapping extensions and MIME
 998       * types to media types.
 999       *
1000       * @todo analyse file if need be
1001       * @todo look at multiple extension, separately and together.
1002       *
1003       * @param string $path Full path to the image file, in case we have to look at the contents
1004       *        (if null, only the MIME type is used to determine the media type code).
1005       * @param string $mime MIME type. If null it will be guessed using guessMimeType.
1006       *
1007       * @return string A value to be used with the MEDIATYPE_xxx constants.
1008       */
1009  	function getMediaType( $path = null, $mime = null ) {
1010          if ( !$mime && !$path ) {
1011              return MEDIATYPE_UNKNOWN;
1012          }
1013  
1014          // If MIME type is unknown, guess it
1015          if ( !$mime ) {
1016              $mime = $this->guessMimeType( $path, false );
1017          }
1018  
1019          // Special code for ogg - detect if it's video (theora),
1020          // else label it as sound.
1021          if ( $mime == 'application/ogg' && file_exists( $path ) ) {
1022  
1023              // Read a chunk of the file
1024              $f = fopen( $path, "rt" );
1025              if ( !$f ) {
1026                  return MEDIATYPE_UNKNOWN;
1027              }
1028              $head = fread( $f, 256 );
1029              fclose( $f );
1030  
1031              $head = str_replace( 'ffmpeg2theora', '', strtolower( $head ) );
1032  
1033              // This is an UGLY HACK, file should be parsed correctly
1034              if ( strpos( $head, 'theora' ) !== false ) {
1035                  return MEDIATYPE_VIDEO;
1036              } elseif ( strpos( $head, 'vorbis' ) !== false ) {
1037                  return MEDIATYPE_AUDIO;
1038              } elseif ( strpos( $head, 'flac' ) !== false ) {
1039                  return MEDIATYPE_AUDIO;
1040              } elseif ( strpos( $head, 'speex' ) !== false ) {
1041                  return MEDIATYPE_AUDIO;
1042              } else {
1043                  return MEDIATYPE_MULTIMEDIA;
1044              }
1045          }
1046  
1047          // Check for entry for full MIME type
1048          if ( $mime ) {
1049              $type = $this->findMediaType( $mime );
1050              if ( $type !== MEDIATYPE_UNKNOWN ) {
1051                  return $type;
1052              }
1053          }
1054  
1055          // Check for entry for file extension
1056          if ( $path ) {
1057              $i = strrpos( $path, '.' );
1058              $e = strtolower( $i ? substr( $path, $i + 1 ) : '' );
1059  
1060              // TODO: look at multi-extension if this fails, parse from full path
1061              $type = $this->findMediaType( '.' . $e );
1062              if ( $type !== MEDIATYPE_UNKNOWN ) {
1063                  return $type;
1064              }
1065          }
1066  
1067          // Check major MIME type
1068          if ( $mime ) {
1069              $i = strpos( $mime, '/' );
1070              if ( $i !== false ) {
1071                  $major = substr( $mime, 0, $i );
1072                  $type = $this->findMediaType( $major );
1073                  if ( $type !== MEDIATYPE_UNKNOWN ) {
1074                      return $type;
1075                  }
1076              }
1077          }
1078  
1079          if ( !$type ) {
1080              $type = MEDIATYPE_UNKNOWN;
1081          }
1082  
1083          return $type;
1084      }
1085  
1086      /**
1087       * Returns a media code matching the given MIME type or file extension.
1088       * File extensions are represented by a string starting with a dot (.) to
1089       * distinguish them from MIME types.
1090       *
1091       * This function relies on the mapping defined by $this->mMediaTypes
1092       * @access private
1093       * @param string $extMime
1094       * @return int|string
1095       */
1096  	function findMediaType( $extMime ) {
1097          if ( strpos( $extMime, '.' ) === 0 ) {
1098              // If it's an extension, look up the MIME types
1099              $m = $this->getTypesForExtension( substr( $extMime, 1 ) );
1100              if ( !$m ) {
1101                  return MEDIATYPE_UNKNOWN;
1102              }
1103  
1104              $m = explode( ' ', $m );
1105          } else {
1106              // Normalize MIME type
1107              if ( isset( $this->mMimeTypeAliases[$extMime] ) ) {
1108                  $extMime = $this->mMimeTypeAliases[$extMime];
1109              }
1110  
1111              $m = array( $extMime );
1112          }
1113  
1114          foreach ( $m as $mime ) {
1115              foreach ( $this->mMediaTypes as $type => $codes ) {
1116                  if ( in_array( $mime, $codes, true ) ) {
1117                      return $type;
1118                  }
1119              }
1120          }
1121  
1122          return MEDIATYPE_UNKNOWN;
1123      }
1124  
1125      /**
1126       * Get the MIME types that various versions of Internet Explorer would
1127       * detect from a chunk of the content.
1128       *
1129       * @param string $fileName The file name (unused at present)
1130       * @param string $chunk The first 256 bytes of the file
1131       * @param string $proposed The MIME type proposed by the server
1132       * @return array
1133       */
1134  	public function getIEMimeTypes( $fileName, $chunk, $proposed ) {
1135          $ca = $this->getIEContentAnalyzer();
1136          return $ca->getRealMimesFromData( $fileName, $chunk, $proposed );
1137      }
1138  
1139      /**
1140       * Get a cached instance of IEContentAnalyzer
1141       *
1142       * @return IEContentAnalyzer
1143       */
1144  	protected function getIEContentAnalyzer() {
1145          if ( is_null( $this->mIEAnalyzer ) ) {
1146              $this->mIEAnalyzer = new IEContentAnalyzer;
1147          }
1148          return $this->mIEAnalyzer;
1149      }
1150  }