includes/db/DatabaseError.php

   1 <?php
   2 /**
   3  * This file contains database error classes.
   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 Database
  22  */
  23
  24 /**
  25  * Database error base class
  26  * @ingroup Database
  27  */
  28 class DBError extends MWException {
  29         /** @var DatabaseBase */
  30         public $db;
  31
  32         /**
  33          * Construct a database error
  34          * @param DatabaseBase $db Object which threw the error
  35          * @param string $error A simple error message to be used for debugging
  36          */
  37         function __construct( DatabaseBase $db = null, $error ) {
  38                 $this->db = $db;
  39                 parent::__construct( $error );
  40         }
  41 }
  42
  43 /**
  44  * Base class for the more common types of database errors. These are known to occur
  45  * frequently, so we try to give friendly error messages for them.
  46  *
  47  * @ingroup Database
  48  * @since 1.23
  49  */
  50 class DBExpectedError extends DBError {
  51         /**
  52          * @return string
  53          */
  54         function getText() {
  55                 global $wgShowDBErrorBacktrace;
  56
  57                 $s = $this->getTextContent() . "\n";
  58
  59                 if ( $wgShowDBErrorBacktrace ) {
  60                         $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
  61                 }
  62
  63                 return $s;
  64         }
  65
  66         /**
  67          * @return string
  68          */
  69         function getHTML() {
  70                 global $wgShowDBErrorBacktrace;
  71
  72                 $s = $this->getHTMLContent();
  73
  74                 if ( $wgShowDBErrorBacktrace ) {
  75                         $s .= '<p>Backtrace:</p><pre>' . htmlspecialchars( $this->getTraceAsString() ) . '</pre>';
  76                 }
  77
  78                 return $s;
  79         }
  80
  81         function getPageTitle() {
  82                 return $this->msg( 'databaseerror', 'Database error' );
  83         }
  84
  85         /**
  86          * @return string
  87          */
  88         protected function getTextContent() {
  89                 return $this->getMessage();
  90         }
  91
  92         /**
  93          * @return string
  94          */
  95         protected function getHTMLContent() {
  96                 return '<p>' . nl2br( htmlspecialchars( $this->getTextContent() ) ) . '</p>';
  97         }
  98 }
  99
 100 /**
 101  * @ingroup Database
 102  */
 103 class DBConnectionError extends DBExpectedError {
 104         /** @var string Error text */
 105         public $error;
 106
 107         /**
 108          * @param DatabaseBase $db Object throwing the error
 109          * @param string $error Error text
 110          */
 111         function __construct( DatabaseBase $db = null, $error = 'unknown error' ) {
 112                 $msg = 'DB connection error';
 113
 114                 if ( trim( $error ) != '' ) {
 115                         $msg .= ": $error";
 116                 } elseif ( $db ) {
 117                         $error = $this->db->getServer();
 118                 }
 119
 120                 parent::__construct( $db, $msg );
 121                 $this->error = $error;
 122         }
 123
 124         /**
 125          * @return bool
 126          */
 127         function useOutputPage() {
 128                 // Not likely to work
 129                 return false;
 130         }
 131
 132         /**
 133          * @param string $key
 134          * @param string $fallback Unescaped alternative error text in case the
 135          *   message cache cannot be used. Can contain parameters as in regular
 136          *   messages, that should be passed as additional parameters.
 137          * @return string Unprocessed plain error text with parameters replaced
 138          */
 139         function msg( $key, $fallback /*[, params...] */ ) {
 140                 $args = array_slice( func_get_args(), 2 );
 141
 142                 if ( $this->useMessageCache() ) {
 143                         return wfMessage( $key, $args )->useDatabase( false )->text();
 144                 } else {
 145                         return wfMsgReplaceArgs( $fallback, $args );
 146                 }
 147         }
 148
 149         /**
 150          * @return bool
 151          */
 152         function isLoggable() {
 153                 // Don't send to the exception log, already in dberror log
 154                 return false;
 155         }
 156
 157         /**
 158          * @return string Safe HTML
 159          */
 160         function getHTML() {
 161                 global $wgShowDBErrorBacktrace, $wgShowHostnames, $wgShowSQLErrors;
 162
 163                 $sorry = htmlspecialchars( $this->msg(
 164                         'dberr-problems',
 165                         'Sorry! This site is experiencing technical difficulties.'
 166                 ) );
 167                 $again = htmlspecialchars( $this->msg(
 168                         'dberr-again',
 169                         'Try waiting a few minutes and reloading.'
 170                 ) );
 171
 172                 if ( $wgShowHostnames || $wgShowSQLErrors ) {
 173                         $info = str_replace(
 174                                 '$1', Html::element( 'span', [ 'dir' => 'ltr' ], $this->error ),
 175                                 htmlspecialchars( $this->msg( 'dberr-info', '(Cannot access the database: $1)' ) )
 176                         );
 177                 } else {
 178                         $info = htmlspecialchars( $this->msg(
 179                                 'dberr-info-hidden',
 180                                 '(Cannot access the database)'
 181                         ) );
 182                 }
 183
 184                 # No database access
 185                 MessageCache::singleton()->disable();
 186
 187                 $html = "<h1>$sorry</h1><p>$again</p><p><small>$info</small></p>";
 188
 189                 if ( $wgShowDBErrorBacktrace ) {
 190                         $html .= '<p>Backtrace:</p><pre>' . htmlspecialchars( $this->getTraceAsString() ) . '</pre>';
 191                 }
 192
 193                 $html .= '<hr />';
 194                 $html .= $this->searchForm();
 195
 196                 return $html;
 197         }
 198
 199         protected function getTextContent() {
 200                 global $wgShowHostnames, $wgShowSQLErrors;
 201
 202                 if ( $wgShowHostnames || $wgShowSQLErrors ) {
 203                         return $this->getMessage();
 204                 } else {
 205                         return 'DB connection error';
 206                 }
 207         }
 208
 209         /**
 210          * Output the exception report using HTML.
 211          *
 212          * @return void
 213          */
 214         public function reportHTML() {
 215                 global $wgUseFileCache;
 216
 217                 // Check whether we can serve a file-cached copy of the page with the error underneath
 218                 if ( $wgUseFileCache ) {
 219                         try {
 220                                 $cache = $this->fileCachedPage();
 221                                 // Cached version on file system?
 222                                 if ( $cache !== null ) {
 223                                         // Hack: extend the body for error messages
 224                                         $cache = str_replace( [ '</html>', '</body>' ], '', $cache );
 225                                         // Add cache notice...
 226                                         $cache .= '<div style="border:1px solid #ffd0d0;padding:1em;">' .
 227                                                 htmlspecialchars( $this->msg( 'dberr-cachederror',
 228                                                         'This is a cached copy of the requested page, and may not be up to date.' ) ) .
 229                                                 '</div>';
 230
 231                                         // Output cached page with notices on bottom and re-close body
 232                                         echo "{$cache}<hr />{$this->getHTML()}</body></html>";
 233
 234                                         return;
 235                                 }
 236                         } catch ( Exception $e ) {
 237                                 // Do nothing, just use the default page
 238                         }
 239                 }
 240
 241                 // We can't, cough and die in the usual fashion
 242                 parent::reportHTML();
 243         }
 244
 245         /**
 246          * @return string
 247          */
 248         function searchForm() {
 249                 global $wgSitename, $wgCanonicalServer, $wgRequest;
 250
 251                 $usegoogle = htmlspecialchars( $this->msg(
 252                         'dberr-usegoogle',
 253                         'You can try searching via Google in the meantime.'
 254                 ) );
 255                 $outofdate = htmlspecialchars( $this->msg(
 256                         'dberr-outofdate',
 257                         'Note that their indexes of our content may be out of date.'
 258                 ) );
 259                 $googlesearch = htmlspecialchars( $this->msg( 'searchbutton', 'Search' ) );
 260
 261                 $search = htmlspecialchars( $wgRequest->getVal( 'search' ) );
 262
 263                 $server = htmlspecialchars( $wgCanonicalServer );
 264                 $sitename = htmlspecialchars( $wgSitename );
 265
 266                 $trygoogle = <<<EOT
 267 <div style="margin: 1.5em">$usegoogle<br />
 268 <small>$outofdate</small>
 269 </div>
 270 <form method="get" action="//www.google.com/search" id="googlesearch">
 271         <input type="hidden" name="domains" value="$server" />
 272         <input type="hidden" name="num" value="50" />
 273         <input type="hidden" name="ie" value="UTF-8" />
 274         <input type="hidden" name="oe" value="UTF-8" />
 275
 276         <input type="text" name="q" size="31" maxlength="255" value="$search" />
 277         <input type="submit" name="btnG" value="$googlesearch" />
 278         <p>
 279                 <label><input type="radio" name="sitesearch" value="$server" checked="checked" />$sitename</label>
 280                 <label><input type="radio" name="sitesearch" value="" />WWW</label>
 281         </p>
 282 </form>
 283 EOT;
 284
 285                 return $trygoogle;
 286         }
 287
 288         /**
 289          * @return string
 290          */
 291         private function fileCachedPage() {
 292                 $context = RequestContext::getMain();
 293
 294                 if ( $context->getOutput()->isDisabled() ) {
 295                         // Done already?
 296                         return '';
 297                 }
 298
 299                 if ( $context->getTitle() ) {
 300                         // Use the main context's title if we managed to set it
 301                         $t = $context->getTitle()->getPrefixedDBkey();
 302                 } else {
 303                         // Fallback to the raw title URL param. We can't use the Title
 304                         // class is it may hit the interwiki table and give a DB error.
 305                         // We may get a cache miss due to not sanitizing the title though.
 306                         $t = str_replace( ' ', '_', $context->getRequest()->getVal( 'title' ) );
 307                         if ( $t == '' ) { // fallback to main page
 308                                 $t = Title::newFromText(
 309                                         $this->msg( 'mainpage', 'Main Page' ) )->getPrefixedDBkey();
 310                         }
 311                 }
 312
 313                 $cache = new HTMLFileCache( $t, 'view' );
 314                 if ( $cache->isCached() ) {
 315                         return $cache->fetchText();
 316                 } else {
 317                         return '';
 318                 }
 319         }
 320 }
 321
 322 /**
 323  * @ingroup Database
 324  */
 325 class DBQueryError extends DBExpectedError {
 326         public $error, $errno, $sql, $fname;
 327
 328         /**
 329          * @param DatabaseBase $db
 330          * @param string $error
 331          * @param int|string $errno
 332          * @param string $sql
 333          * @param string $fname
 334          */
 335         function __construct( DatabaseBase $db, $error, $errno, $sql, $fname ) {
 336                 if ( $db->wasConnectionError( $errno ) ) {
 337                         $message = "A connection error occured. \n" .
 338                                 "Query: $sql\n" .
 339                                 "Function: $fname\n" .
 340                                 "Error: $errno $error\n";
 341                 } else {
 342                         $message = "A database error has occurred. Did you forget to run " .
 343                                 "maintenance/update.php after upgrading?  See: " .
 344                                 "https://www.mediawiki.org/wiki/Manual:Upgrading#Run_the_update_script\n" .
 345                                 "Query: $sql\n" .
 346                                 "Function: $fname\n" .
 347                                 "Error: $errno $error\n";
 348                 }
 349                 parent::__construct( $db, $message );
 350
 351                 $this->error = $error;
 352                 $this->errno = $errno;
 353                 $this->sql = $sql;
 354                 $this->fname = $fname;
 355         }
 356
 357         /**
 358          * @return string
 359          */
 360         function getPageTitle() {
 361                 return $this->msg( 'databaseerror', 'Database error' );
 362         }
 363
 364         /**
 365          * @return string
 366          */
 367         protected function getHTMLContent() {
 368                 $key = 'databaseerror-text';
 369                 $s = Html::element( 'p', [], $this->msg( $key, $this->getFallbackMessage( $key ) ) );
 370
 371                 $details = $this->getTechnicalDetails();
 372                 if ( $details ) {
 373                         $s .= '<ul>';
 374                         foreach ( $details as $key => $detail ) {
 375                                 $s .= str_replace(
 376                                         '$1', call_user_func_array( 'Html::element', $detail ),
 377                                         Html::element( 'li', [],
 378                                                 $this->msg( $key, $this->getFallbackMessage( $key ) )
 379                                         )
 380                                 );
 381                         }
 382                         $s .= '</ul>';
 383                 }
 384
 385                 return $s;
 386         }
 387
 388         /**
 389          * @return string
 390          */
 391         protected function getTextContent() {
 392                 $key = 'databaseerror-textcl';
 393                 $s = $this->msg( $key, $this->getFallbackMessage( $key ) ) . "\n";
 394
 395                 foreach ( $this->getTechnicalDetails() as $key => $detail ) {
 396                         $s .= $this->msg( $key, $this->getFallbackMessage( $key ), $detail[2] ) . "\n";
 397                 }
 398
 399                 return $s;
 400         }
 401
 402         /**
 403          * Make a list of technical details that can be shown to the user. This information can
 404          * aid in debugging yet may be useful to an attacker trying to exploit a security weakness
 405          * in the software or server configuration.
 406          *
 407          * Thus no such details are shown by default, though if $wgShowHostnames is true, only the
 408          * full SQL query is hidden; in fact, the error message often does contain a hostname, and
 409          * sites using this option probably don't care much about "security by obscurity". Of course,
 410          * if $wgShowSQLErrors is true, the SQL query *is* shown.
 411          *
 412          * @return array Keys are message keys; values are arrays of arguments for Html::element().
 413          *   Array will be empty if users are not allowed to see any of these details at all.
 414          */
 415         protected function getTechnicalDetails() {
 416                 global $wgShowHostnames, $wgShowSQLErrors;
 417
 418                 $attribs = [ 'dir' => 'ltr' ];
 419                 $details = [];
 420
 421                 if ( $wgShowSQLErrors ) {
 422                         $details['databaseerror-query'] = [
 423                                 'div', [ 'class' => 'mw-code' ] + $attribs, $this->sql ];
 424                 }
 425
 426                 if ( $wgShowHostnames || $wgShowSQLErrors ) {
 427                         $errorMessage = $this->errno . ' ' . $this->error;
 428                         $details['databaseerror-function'] = [ 'code', $attribs, $this->fname ];
 429                         $details['databaseerror-error'] = [ 'samp', $attribs, $errorMessage ];
 430                 }
 431
 432                 return $details;
 433         }
 434
 435         /**
 436          * @param string $key Message key
 437          * @return string English message text
 438          */
 439         private function getFallbackMessage( $key ) {
 440                 $messages = [
 441                         'databaseerror-text' => 'A database query error has occurred.
 442 This may indicate a bug in the software.',
 443                         'databaseerror-textcl' => 'A database query error has occurred.',
 444                         'databaseerror-query' => 'Query: $1',
 445                         'databaseerror-function' => 'Function: $1',
 446                         'databaseerror-error' => 'Error: $1',
 447                 ];
 448
 449                 return $messages[$key];
 450         }
 451 }
 452
 453 /**
 454  * @ingroup Database
 455  */
 456 class DBUnexpectedError extends DBError {
 457 }
 458
 459 /**
 460  * @ingroup Database
 461  */
 462 class DBReadOnlyError extends DBExpectedError {
 463         function getPageTitle() {
 464                 return $this->msg( 'readonly', 'Database is locked' );
 465         }
 466 }
 467
 468 /**
 469  * @ingroup Database
 470  */
 471 class DBTransactionError extends DBExpectedError {
 472 }