includes/installer/Installer.php

   1 <?php
   2 /**
   3  * Base code for MediaWiki installer.
   4  *
   5  * @file
   6  * @ingroup Deployment
   7  */
   8
   9 /**
  10  * This documentation group collects source code files with deployment functionality.
  11  *
  12  * @defgroup Deployment Deployment
  13  */
  14
  15 /**
  16  * Base installer class.
  17  *
  18  * This class provides the base for installation and update functionality
  19  * for both MediaWiki core and extensions.
  20  *
  21  * @ingroup Deployment
  22  * @since 1.17
  23  */
  24 abstract class Installer {
  25
  26         /**
  27          * TODO: make protected?
  28          *
  29          * @var array
  30          */
  31         public $settings;
  32
  33         /**
  34          * Cached DB installer instances, access using getDBInstaller().
  35          *
  36          * @var array
  37          */
  38         protected $dbInstallers = array();
  39
  40         /**
  41          * Minimum memory size in MB.
  42          *
  43          * @var integer
  44          */
  45         protected $minMemorySize = 50;
  46
  47         /**
  48          * Cached Title, used by parse().
  49          *
  50          * @var Title
  51          */
  52         protected $parserTitle;
  53
  54         /**
  55          * Cached ParserOptions, used by parse().
  56          *
  57          * @var ParserOptions
  58          */
  59         protected $parserOptions;
  60
  61         /**
  62          * Known database types. These correspond to the class names <type>Installer,
  63          * and are also MediaWiki database types valid for $wgDBtype.
  64          *
  65          * To add a new type, create a <type>Installer class and a Database<type>
  66          * class, and add a config-type-<type> message to MessagesEn.php.
  67          *
  68          * @var array
  69          */
  70         protected static $dbTypes = array(
  71                 'mysql',
  72                 'postgres',
  73                 'oracle',
  74                 'sqlite',
  75         );
  76
  77         /**
  78          * A list of environment check methods called by doEnvironmentChecks().
  79          * These may output warnings using showMessage(), and/or abort the
  80          * installation process by returning false.
  81          *
  82          * @var array
  83          */
  84         protected $envChecks = array(
  85                 'envCheckDB',
  86                 'envCheckRegisterGlobals',
  87                 'envCheckBrokenXML',
  88                 'envCheckPHP531',
  89                 'envCheckMagicQuotes',
  90                 'envCheckMagicSybase',
  91                 'envCheckMbstring',
  92                 'envCheckZE1',
  93                 'envCheckSafeMode',
  94                 'envCheckXML',
  95                 'envCheckPCRE',
  96                 'envCheckMemory',
  97                 'envCheckCache',
  98                 'envCheckDiff3',
  99                 'envCheckGraphics',
 100                 'envCheckPath',
 101                 'envCheckExtension',
 102                 'envCheckShellLocale',
 103                 'envCheckUploadsDirectory',
 104                 'envCheckLibicu'
 105         );
 106
 107         /**
 108          * UI interface for displaying a short message
 109          * The parameters are like parameters to wfMsg().
 110          * The messages will be in wikitext format, which will be converted to an
 111          * output format such as HTML or text before being sent to the user.
 112          */
 113         public abstract function showMessage( $msg /*, ... */ );
 114
 115         /**
 116          * Constructor, always call this from child classes.
 117          */
 118         public function __construct() {
 119                 // Disable the i18n cache and LoadBalancer
 120                 Language::getLocalisationCache()->disableBackend();
 121                 LBFactory::disableBackend();
 122         }
 123
 124         /**
 125          * Get a list of known DB types.
 126          */
 127         public static function getDBTypes() {
 128                 return self::$dbTypes;
 129         }
 130
 131         /**
 132          * Do initial checks of the PHP environment. Set variables according to
 133          * the observed environment.
 134          *
 135          * It's possible that this may be called under the CLI SAPI, not the SAPI
 136          * that the wiki will primarily run under. In that case, the subclass should
 137          * initialise variables such as wgScriptPath, before calling this function.
 138          *
 139          * Under the web subclass, it can already be assumed that PHP 5+ is in use
 140          * and that sessions are working.
 141          *
 142          * @return boolean
 143          */
 144         public function doEnvironmentChecks() {
 145                 $good = true;
 146
 147                 foreach ( $this->envChecks as $check ) {
 148                         $status = $this->$check();
 149                         if ( $status === false ) {
 150                                 $good = false;
 151                         }
 152                 }
 153
 154                 $this->setVar( '_Environment', $good );
 155
 156                 if ( $good ) {
 157                         $this->showMessage( 'config-env-good' );
 158                 } else {
 159                         $this->showMessage( 'config-env-bad' );
 160                 }
 161
 162                 return $good;
 163         }
 164
 165         /**
 166          * Set a MW configuration variable, or internal installer configuration variable.
 167          *
 168          * @param $name String
 169          * @param $value Mixed
 170          */
 171         public function setVar( $name, $value ) {
 172                 $this->settings[$name] = $value;
 173         }
 174
 175         /**
 176          * Get an MW configuration variable, or internal installer configuration variable.
 177          * The defaults come from $GLOBALS (ultimately DefaultSettings.php).
 178          * Installer variables are typically prefixed by an underscore.
 179          *
 180          * @param $name String
 181          * @param $default Mixed
 182          *
 183          * @return mixed
 184          */
 185         public function getVar( $name, $default = null ) {
 186                 if ( !isset( $this->settings[$name] ) ) {
 187                         return $default;
 188                 } else {
 189                         return $this->settings[$name];
 190                 }
 191         }
 192
 193         /**
 194          * Get an instance of DatabaseInstaller for the specified DB type.
 195          *
 196          * @param $type Mixed: DB installer for which is needed, false to use default.
 197          *
 198          * @return DatabaseInstaller
 199          */
 200         public function getDBInstaller( $type = false ) {
 201                 if ( !$type ) {
 202                         $type = $this->getVar( 'wgDBtype' );
 203                 }
 204
 205                 $type = strtolower( $type );
 206
 207                 if ( !isset( $this->dbInstallers[$type] ) ) {
 208                         $class = ucfirst( $type ). 'Installer';
 209                         $this->dbInstallers[$type] = new $class( $this );
 210                 }
 211
 212                 return $this->dbInstallers[$type];
 213         }
 214
 215         /**
 216          * Determine if LocalSettings.php exists. If it does, return its variables,
 217          * merged with those from AdminSettings.php, as an array.
 218          *
 219          * @return Array
 220          */
 221         public function getExistingLocalSettings() {
 222                 global $IP;
 223
 224                 wfSuppressWarnings();
 225                 $_lsExists = file_exists( "$IP/LocalSettings.php" );
 226                 wfRestoreWarnings();
 227
 228                 if( !$_lsExists ) {
 229                         return false;
 230                 }
 231                 unset($_lsExists);
 232
 233                 require( "$IP/includes/DefaultSettings.php" );
 234                 require( "$IP/LocalSettings.php" );
 235                 if ( file_exists( "$IP/AdminSettings.php" ) ) {
 236                         require( "$IP/AdminSettings.php" );
 237                 }
 238                 return get_defined_vars();
 239         }
 240
 241         /**
 242          * Get a fake password for sending back to the user in HTML.
 243          * This is a security mechanism to avoid compromise of the password in the
 244          * event of session ID compromise.
 245          *
 246          * @param $realPassword String
 247          *
 248          * @return string
 249          */
 250         public function getFakePassword( $realPassword ) {
 251                 return str_repeat( '*', strlen( $realPassword ) );
 252         }
 253
 254         /**
 255          * Set a variable which stores a password, except if the new value is a
 256          * fake password in which case leave it as it is.
 257          *
 258          * @param $name String
 259          * @param $value Mixed
 260          */
 261         public function setPassword( $name, $value ) {
 262                 if ( !preg_match( '/^\*+$/', $value ) ) {
 263                         $this->setVar( $name, $value );
 264                 }
 265         }
 266
 267         /**
 268          * On POSIX systems return the primary group of the webserver we're running under.
 269          * On other systems just returns null.
 270          *
 271          * This is used to advice the user that he should chgrp his config/data/images directory as the
 272          * webserver user before he can install.
 273          *
 274          * Public because SqliteInstaller needs it, and doesn't subclass Installer.
 275          *
 276          * @return mixed
 277          */
 278         public static function maybeGetWebserverPrimaryGroup() {
 279                 if ( !function_exists( 'posix_getegid' ) || !function_exists( 'posix_getpwuid' ) ) {
 280                         # I don't know this, this isn't UNIX.
 281                         return null;
 282                 }
 283
 284                 # posix_getegid() *not* getmygid() because we want the group of the webserver,
 285                 # not whoever owns the current script.
 286                 $gid = posix_getegid();
 287                 $getpwuid = posix_getpwuid( $gid );
 288                 $group = $getpwuid['name'];
 289
 290                 return $group;
 291         }
 292
 293         /**
 294          * Convert wikitext $text to HTML.
 295          *
 296          * This is potentially error prone since many parser features require a complete
 297          * installed MW database. The solution is to just not use those features when you
 298          * write your messages. This appears to work well enough. Basic formatting and
 299          * external links work just fine.
 300          *
 301          * But in case a translator decides to throw in a #ifexist or internal link or
 302          * whatever, this function is guarded to catch the attempted DB access and to present
 303          * some fallback text.
 304          *
 305          * @param $text String
 306          * @param $lineStart Boolean
 307          * @return String
 308          */
 309         public function parse( $text, $lineStart = false ) {
 310                 global $wgParser;
 311
 312                 try {
 313                         $out = $wgParser->parse( $text, $this->parserTitle, $this->parserOptions, $lineStart );
 314                         $html = $out->getText();
 315                 } catch ( DBAccessError $e ) {
 316                         $html = '<!--DB access attempted during parse-->  ' . htmlspecialchars( $text );
 317
 318                         if ( !empty( $this->debug ) ) {
 319                                 $html .= "<!--\n" . $e->getTraceAsString() . "\n-->";
 320                         }
 321                 }
 322
 323                 return $html;
 324         }
 325
 326         public function getParserOptions() {
 327                 return $this->parserOptions;
 328         }
 329
 330         public function disableLinkPopups() {
 331                 $this->parserOptions->setExternalLinkTarget( false );
 332         }
 333
 334         public function restoreLinkPopups() {
 335                 global $wgExternalLinkTarget;
 336                 $this->parserOptions->setExternalLinkTarget( $wgExternalLinkTarget );
 337         }
 338
 339         /**
 340          * TODO: document
 341          *
 342          * @param $installer DatabaseInstaller
 343          *
 344          * @return Status
 345          */
 346         public function installTables( DatabaseInstaller &$installer ) {
 347                 $status = $installer->createTables();
 348
 349                 if( $status->isOK() ) {
 350                         LBFactory::enableBackend();
 351                 }
 352
 353                 return $status;
 354         }
 355
 356         /**
 357          * Exports all wg* variables stored by the installer into global scope.
 358          */
 359         public function exportVars() {
 360                 foreach ( $this->settings as $name => $value ) {
 361                         if ( substr( $name, 0, 2 ) == 'wg' ) {
 362                                 $GLOBALS[$name] = $value;
 363                         }
 364                 }
 365         }
 366
 367         /**
 368          * Environment check for DB types.
 369          */
 370         protected function envCheckDB() {
 371                 global $wgLang;
 372
 373                 $compiledDBs = array();
 374                 $goodNames = array();
 375                 $allNames = array();
 376
 377                 foreach ( self::getDBTypes() as $name ) {
 378                         $db = $this->getDBInstaller( $name );
 379                         $readableName = wfMsg( 'config-type-' . $name );
 380
 381                         if ( $db->isCompiled() ) {
 382                                 $compiledDBs[] = $name;
 383                                 $goodNames[] = $readableName;
 384                         }
 385
 386                         $allNames[] = $readableName;
 387                 }
 388
 389                 $this->setVar( '_CompiledDBs', $compiledDBs );
 390
 391                 if ( !$compiledDBs ) {
 392                         $this->showMessage( 'config-no-db' );
 393                         // FIXME: this only works for the web installer!
 394                         $this->showHelpBox( 'config-no-db-help', $wgLang->commaList( $allNames ) );
 395                         return false;
 396                 }
 397
 398                 // Check for FTS3 full-text search module
 399                 $sqlite = $this->getDBInstaller( 'sqlite' );
 400                 if ( $sqlite->isCompiled() ) {
 401                         $db = new DatabaseSqliteStandalone( ':memory:' );
 402                         if( $db->getFulltextSearchModule() != 'FTS3' ) {
 403                                 $this->showMessage( 'config-no-fts3' );
 404                         }
 405                 }
 406         }
 407
 408         /**
 409          * Environment check for register_globals.
 410          */
 411         protected function envCheckRegisterGlobals() {
 412                 if( wfIniGetBool( "magic_quotes_runtime" ) ) {
 413                         $this->showMessage( 'config-register-globals' );
 414                 }
 415         }
 416
 417         /**
 418          * Some versions of libxml+PHP break < and > encoding horribly
 419          */
 420         protected function envCheckBrokenXML() {
 421                 $test = new PhpXmlBugTester();
 422                 if ( !$test->ok ) {
 423                         $this->showMessage( 'config-brokenlibxml' );
 424                         return false;
 425                 }
 426         }
 427
 428         /**
 429          * Test PHP (probably 5.3.1, but it could regress again) to make sure that
 430          * reference parameters to __call() are not converted to null
 431          */
 432         protected function envCheckPHP531() {
 433                 $test = new PhpRefCallBugTester;
 434                 $test->execute();
 435                 if ( !$test->ok ) {
 436                         $this->showMessage( 'config-using531' );
 437                         return false;
 438                 }
 439         }
 440
 441         /**
 442          * Environment check for magic_quotes_runtime.
 443          */
 444         protected function envCheckMagicQuotes() {
 445                 if( wfIniGetBool( "magic_quotes_runtime" ) ) {
 446                         $this->showMessage( 'config-magic-quotes-runtime' );
 447                         return false;
 448                 }
 449         }
 450
 451         /**
 452          * Environment check for magic_quotes_sybase.
 453          */
 454         protected function envCheckMagicSybase() {
 455                 if ( wfIniGetBool( 'magic_quotes_sybase' ) ) {
 456                         $this->showMessage( 'config-magic-quotes-sybase' );
 457                         return false;
 458                 }
 459         }
 460
 461         /**
 462          * Environment check for mbstring.func_overload.
 463          */
 464         protected function envCheckMbstring() {
 465                 if ( wfIniGetBool( 'mbstring.func_overload' ) ) {
 466                         $this->showMessage( 'config-mbstring' );
 467                         return false;
 468                 }
 469         }
 470
 471         /**
 472          * Environment check for zend.ze1_compatibility_mode.
 473          */
 474         protected function envCheckZE1() {
 475                 if ( wfIniGetBool( 'zend.ze1_compatibility_mode' ) ) {
 476                         $this->showMessage( 'config-ze1' );
 477                         return false;
 478                 }
 479         }
 480
 481         /**
 482          * Environment check for safe_mode.
 483          */
 484         protected function envCheckSafeMode() {
 485                 if ( wfIniGetBool( 'safe_mode' ) ) {
 486                         $this->setVar( '_SafeMode', true );
 487                         $this->showMessage( 'config-safe-mode' );
 488                 }
 489         }
 490
 491         /**
 492          * Environment check for the XML module.
 493          */
 494         protected function envCheckXML() {
 495                 if ( !function_exists( "utf8_encode" ) ) {
 496                         $this->showMessage( 'config-xml-bad' );
 497                         return false;
 498                 }
 499         }
 500
 501         /**
 502          * Environment check for the PCRE module.
 503          */
 504         protected function envCheckPCRE() {
 505                 if ( !function_exists( 'preg_match' ) ) {
 506                         $this->showMessage( 'config-pcre' );
 507                         return false;
 508                 }
 509                 wfSuppressWarnings();
 510                 $regexd = preg_replace( '/[\x{0400}-\x{04FF}]/u', '', '-АБВГД-' );
 511                 wfRestoreWarnings();
 512                 if ( $regexd != '--' ) {
 513                         $this->showMessage( 'config-pcre-no-utf8' );
 514                         return false;
 515                 }
 516         }
 517
 518         /**
 519          * Environment check for available memory.
 520          */
 521         protected function envCheckMemory() {
 522                 $limit = ini_get( 'memory_limit' );
 523
 524                 if ( !$limit || $limit == -1 ) {
 525                         return true;
 526                 }
 527
 528                 $n = intval( $limit );
 529
 530                 if( preg_match( '/^([0-9]+)[Mm]$/', trim( $limit ), $m ) ) {
 531                         $n = intval( $m[1] * ( 1024 * 1024 ) );
 532                 }
 533
 534                 if( $n < $this->minMemorySize * 1024 * 1024 ) {
 535                         $newLimit = "{$this->minMemorySize}M";
 536
 537                         if( ini_set( "memory_limit", $newLimit ) === false ) {
 538                                 $this->showMessage( 'config-memory-bad', $limit );
 539                         } else {
 540                                 $this->showMessage( 'config-memory-raised', $limit, $newLimit );
 541                                 $this->setVar( '_RaiseMemory', true );
 542                         }
 543                 } else {
 544                         return true;
 545                 }
 546         }
 547
 548         /**
 549          * Environment check for compiled object cache types.
 550          */
 551         protected function envCheckCache() {
 552                 $caches = array();
 553                 foreach ( $this->objectCaches as $name => $function ) {
 554                         if ( function_exists( $function ) ) {
 555                                 $caches[$name] = true;
 556                         }
 557                 }
 558
 559                 if ( !$caches ) {
 560                         $this->showMessage( 'config-no-cache' );
 561                 }
 562
 563                 $this->setVar( '_Caches', $caches );
 564         }
 565
 566         /**
 567          * Search for GNU diff3.
 568          */
 569         protected function envCheckDiff3() {
 570                 $names = array( "gdiff3", "diff3", "diff3.exe" );
 571                 $versionInfo = array( '$1 --version 2>&1', 'GNU diffutils' );
 572
 573                 $diff3 = self::locateExecutableInDefaultPaths( $names, $versionInfo );
 574
 575                 if ( $diff3 ) {
 576                         $this->setVar( 'wgDiff3', $diff3 );
 577                 } else {
 578                         $this->setVar( 'wgDiff3', false );
 579                         $this->showMessage( 'config-diff3-bad' );
 580                 }
 581         }
 582
 583         /**
 584          * Environment check for ImageMagick and GD.
 585          */
 586         protected function envCheckGraphics() {
 587                 $names = array( wfIsWindows() ? 'convert.exe' : 'convert' );
 588                 $convert = self::locateExecutableInDefaultPaths( $names, array( '$1 -version', 'ImageMagick' ) );
 589
 590                 if ( $convert ) {
 591                         $this->setVar( 'wgImageMagickConvertCommand', $convert );
 592                         $this->showMessage( 'config-imagemagick', $convert );
 593                         return true;
 594                 } elseif ( function_exists( 'imagejpeg' ) ) {
 595                         $this->showMessage( 'config-gd' );
 596                         return true;
 597                 } else {
 598                         $this->showMessage( 'no-scaling' );
 599                 }
 600         }
 601
 602         /**
 603          * Environment check for setting $IP and $wgScriptPath.
 604          */
 605         protected function envCheckPath() {
 606                 global $IP;
 607                 $IP = dirname( dirname( dirname( __FILE__ ) ) );
 608
 609                 $this->setVar( 'IP', $IP );
 610
 611                 // PHP_SELF isn't available sometimes, such as when PHP is CGI but
 612                 // cgi.fix_pathinfo is disabled. In that case, fall back to SCRIPT_NAME
 613                 // to get the path to the current script... hopefully it's reliable. SIGH
 614                 if ( !empty( $_SERVER['PHP_SELF'] ) ) {
 615                         $path = $_SERVER['PHP_SELF'];
 616                 } elseif ( !empty( $_SERVER['SCRIPT_NAME'] ) ) {
 617                         $path = $_SERVER['SCRIPT_NAME'];
 618                 } elseif ( $this->getVar( 'wgScriptPath' ) ) {
 619                         // Some kind soul has set it for us already (e.g. debconf)
 620                         return true;
 621                 } else {
 622                         $this->showMessage( 'config-no-uri' );
 623                         return false;
 624                 }
 625
 626                 $uri = preg_replace( '{^(.*)/config.*$}', '$1', $path );
 627                 $this->setVar( 'wgScriptPath', $uri );
 628         }
 629
 630         /**
 631          * Environment check for setting the preferred PHP file extension.
 632          */
 633         protected function envCheckExtension() {
 634                 // FIXME: detect this properly
 635                 if ( defined( 'MW_INSTALL_PHP5_EXT' ) ) {
 636                         $ext = 'php5';
 637                 } else {
 638                         $ext = 'php';
 639                 }
 640                 $this->setVar( 'wgScriptExtension', ".$ext" );
 641         }
 642
 643         /**
 644          * TODO: document
 645          */
 646         protected function envCheckShellLocale() {
 647                 $os = php_uname( 's' );
 648                 $supported = array( 'Linux', 'SunOS', 'HP-UX', 'Darwin' ); # Tested these
 649
 650                 if ( !in_array( $os, $supported ) ) {
 651                         return true;
 652                 }
 653
 654                 # Get a list of available locales.
 655                 $ret = false;
 656                 $lines = wfShellExec( '/usr/bin/locale -a', $ret );
 657
 658                 if ( $ret ) {
 659                         return true;
 660                 }
 661
 662                 $lines = wfArrayMap( 'trim', explode( "\n", $lines ) );
 663                 $candidatesByLocale = array();
 664                 $candidatesByLang = array();
 665
 666                 foreach ( $lines as $line ) {
 667                         if ( $line === '' ) {
 668                                 continue;
 669                         }
 670
 671                         if ( !preg_match( '/^([a-zA-Z]+)(_[a-zA-Z]+|)\.(utf8|UTF-8)(@[a-zA-Z_]*|)$/i', $line, $m ) ) {
 672                                 continue;
 673                         }
 674
 675                         list( $all, $lang, $territory, $charset, $modifier ) = $m;
 676
 677                         $candidatesByLocale[$m[0]] = $m;
 678                         $candidatesByLang[$lang][] = $m;
 679                 }
 680
 681                 # Try the current value of LANG.
 682                 if ( isset( $candidatesByLocale[ getenv( 'LANG' ) ] ) ) {
 683                         $this->setVar( 'wgShellLocale', getenv( 'LANG' ) );
 684                         return true;
 685                 }
 686
 687                 # Try the most common ones.
 688                 $commonLocales = array( 'en_US.UTF-8', 'en_US.utf8', 'de_DE.UTF-8', 'de_DE.utf8' );
 689                 foreach ( $commonLocales as $commonLocale ) {
 690                         if ( isset( $candidatesByLocale[$commonLocale] ) ) {
 691                                 $this->setVar( 'wgShellLocale', $commonLocale );
 692                                 return true;
 693                         }
 694                 }
 695
 696                 # Is there an available locale in the Wiki's language?
 697                 $wikiLang = $this->getVar( 'wgLanguageCode' );
 698
 699                 if ( isset( $candidatesByLang[$wikiLang] ) ) {
 700                         $m = reset( $candidatesByLang[$wikiLang] );
 701                         $this->setVar( 'wgShellLocale', $m[0] );
 702                         return true;
 703                 }
 704
 705                 # Are there any at all?
 706                 if ( count( $candidatesByLocale ) ) {
 707                         $m = reset( $candidatesByLocale );
 708                         $this->setVar( 'wgShellLocale', $m[0] );
 709                         return true;
 710                 }
 711
 712                 # Give up.
 713                 return true;
 714         }
 715
 716         /**
 717          * TODO: document
 718          */
 719         protected function envCheckUploadsDirectory() {
 720                 global $IP, $wgServer;
 721
 722                 $dir = $IP . '/images/';
 723                 $url = $wgServer . $this->getVar( 'wgScriptPath' ) . '/images/';
 724                 $safe = !$this->dirIsExecutable( $dir, $url );
 725
 726                 if ( $safe ) {
 727                         return true;
 728                 } else {
 729                         $this->showMessage( 'config-uploads-not-safe', $dir );
 730                 }
 731         }
 732
 733         /**
 734          * Convert a hex string representing a Unicode code point to that code point.
 735          * @param $c String
 736          * @return string
 737          */
 738         protected function unicodeChar( $c ) {
 739                 $c = hexdec($c);
 740                 if ($c <= 0x7F) {
 741                         return chr($c);
 742                 } else if ($c <= 0x7FF) {
 743                         return chr(0xC0 | $c >> 6) . chr(0x80 | $c & 0x3F);
 744                 } else if ($c <= 0xFFFF) {
 745                         return chr(0xE0 | $c >> 12) . chr(0x80 | $c >> 6 & 0x3F)
 746                                 . chr(0x80 | $c & 0x3F);
 747                 } else if ($c <= 0x10FFFF) {
 748                         return chr(0xF0 | $c >> 18) . chr(0x80 | $c >> 12 & 0x3F)
 749                                 . chr(0x80 | $c >> 6 & 0x3F)
 750                                 . chr(0x80 | $c & 0x3F);
 751                 } else {
 752                         return false;
 753                 }
 754         }
 755
 756
 757         /**
 758          * Check the libicu version
 759          */
 760         protected function envCheckLibicu() {
 761                 $utf8 = function_exists( 'utf8_normalize' );
 762                 $intl = function_exists( 'normalizer_normalize' );
 763
 764                 /**
 765                  * This needs to be updated something that the latest libicu
 766                  * will properly normalize.  This normalization was found at
 767                  * http://www.unicode.org/versions/Unicode5.2.0/#Character_Additions
 768                  * Note that we use the hex representation to create the code
 769                  * points in order to avoid any Unicode-destroying during transit.
 770                  */
 771                 $not_normal_c = $this->unicodeChar("FA6C");
 772                 $normal_c = $this->unicodeChar("242EE");
 773
 774                 $useNormalizer = 'php';
 775                 $needsUpdate = false;
 776
 777                 /**
 778                  * We're going to prefer the pecl extension here unless
 779                  * utf8_normalize is more up to date.
 780                  */
 781                 if( $utf8 ) {
 782                         $useNormalizer = 'utf8';
 783                         $utf8 = utf8_normalize( $not_normal_c, UNORM_NFC );
 784                         if ( $utf8 !== $normal_c ) $needsUpdate = true;
 785                 }
 786                 if( $intl ) {
 787                         $useNormalizer = 'intl';
 788                         $intl = normalizer_normalize( $not_normal_c, Normalizer::FORM_C );
 789                         if ( $intl !== $normal_c ) $needsUpdate = true;
 790                 }
 791
 792                 // Uses messages 'config-unicode-using-php', 'config-unicode-using-utf8', 'config-unicode-using-intl'
 793                 if( $useNormalizer === 'php' ) {
 794                         $this->showMessage( 'config-unicode-pure-php-warning' );
 795                 } else {
 796                         $this->showMessage( 'config-unicode-using-' . $useNormalizer );
 797                         if( $needsUpdate ) {
 798                                 $this->showMessage( 'config-unicode-update-warning' );
 799                         }
 800                 }
 801         }
 802
 803         /**
 804          * Get an array of likely places we can find executables. Check a bunch
 805          * of known Unix-like defaults, as well as the PATH environment variable
 806          * (which should maybe make it work for Windows?)
 807          *
 808          * @return Array
 809          */
 810         protected static function getPossibleBinPaths() {
 811                 return array_merge(
 812                         array( '/usr/bin', '/usr/local/bin', '/opt/csw/bin',
 813                                 '/usr/gnu/bin', '/usr/sfw/bin', '/sw/bin', '/opt/local/bin' ),
 814                         explode( PATH_SEPARATOR, getenv( 'PATH' ) )
 815                 );
 816         }
 817
 818         /**
 819          * Search a path for any of the given executable names. Returns the
 820          * executable name if found. Also checks the version string returned
 821          * by each executable.
 822          *
 823          * Used only by environment checks.
 824          *
 825          * @param $path String: path to search
 826          * @param $names Array of executable names
 827          * @param $versionInfo Boolean false or array with two members:
 828          *               0 => Command to run for version check, with $1 for the full executable name
 829          *               1 => String to compare the output with
 830          *
 831          * If $versionInfo is not false, only executables with a version
 832          * matching $versionInfo[1] will be returned.
 833          */
 834         public static function locateExecutable( $path, $names, $versionInfo = false ) {
 835                 if ( !is_array( $names ) ) {
 836                         $names = array( $names );
 837                 }
 838
 839                 foreach ( $names as $name ) {
 840                         $command = $path . DIRECTORY_SEPARATOR . $name;
 841
 842                         wfSuppressWarnings();
 843                         $file_exists = file_exists( $command );
 844                         wfRestoreWarnings();
 845
 846                         if ( $file_exists ) {
 847                                 if ( !$versionInfo ) {
 848                                         return $command;
 849                                 }
 850
 851                                 $file = str_replace( '$1', wfEscapeShellArg( $command ), $versionInfo[0] );
 852                                 if ( strstr( wfShellExec( $file ), $versionInfo[1] ) !== false ) {
 853                                         return $command;
 854                                 }
 855                         }
 856                 }
 857                 return false;
 858         }
 859
 860         /**
 861          * Same as locateExecutable(), but checks in getPossibleBinPaths() by default
 862          * @see locateExecutable()
 863          */
 864         public static function locateExecutableInDefaultPaths( $names, $versionInfo = false ) {
 865                 foreach( self::getPossibleBinPaths() as $path ) {
 866                         $exe = self::locateExecutable( $path, $names, $versionInfo );
 867                         if( $exe !== false ) {
 868                                 return $exe;
 869                         }
 870                 }
 871                 return false;
 872         }
 873
 874         /**
 875          * Checks if scripts located in the given directory can be executed via the given URL.
 876          *
 877          * Used only by environment checks.
 878          */
 879         public function dirIsExecutable( $dir, $url ) {
 880                 $scriptTypes = array(
 881                         'php' => array(
 882                                 "<?php echo 'ex' . 'ec';",
 883                                 "#!/var/env php5\n<?php echo 'ex' . 'ec';",
 884                         ),
 885                 );
 886
 887                 // it would be good to check other popular languages here, but it'll be slow.
 888
 889                 wfSuppressWarnings();
 890
 891                 foreach ( $scriptTypes as $ext => $contents ) {
 892                         foreach ( $contents as $source ) {
 893                                 $file = 'exectest.' . $ext;
 894
 895                                 if ( !file_put_contents( $dir . $file, $source ) ) {
 896                                         break;
 897                                 }
 898
 899                                 $text = Http::get( $url . $file );
 900                                 unlink( $dir . $file );
 901
 902                                 if ( $text == 'exec' ) {
 903                                         wfRestoreWarnings();
 904                                         return $ext;
 905                                 }
 906                         }
 907                 }
 908
 909                 wfRestoreWarnings();
 910
 911                 return false;
 912         }
 913
 914 }