includes/shell/Shell.php

   1 <?php
   2 /**
   3  * Class used for executing shell commands
   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 namespace MediaWiki\Shell;
  24
  25 use MediaWiki\Logger\LoggerFactory;
  26 use MediaWiki\MediaWikiServices;
  27
  28 /**
  29  * Executes shell commands
  30  *
  31  * @since 1.30
  32  *
  33  * Use call chaining with this class for expressiveness:
  34  *  $result = Shell::command( 'some command' )
  35  *       ->environment( [ 'ENVIRONMENT_VARIABLE' => 'VALUE' ] )
  36  *       ->limits( [ 'time' => 300 ] )
  37  *       ->execute();
  38  *
  39  *  ... = $result->getExitCode();
  40  *  ... = $result->getStdout();
  41  */
  42 class Shell {
  43
  44         /**
  45          * Returns a new instance of Command class
  46          *
  47          * @param string|string[] $command String or array of strings representing the command to
  48          * be executed, each value will be escaped.
  49          *   Example:   [ 'convert', '-font', 'font name' ] would produce "'convert' '-font' 'font name'"
  50          * @return Command
  51          */
  52         public static function command( $command ) {
  53                 $args = func_get_args();
  54                 if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
  55                         // If only one argument has been passed, and that argument is an array,
  56                         // treat it as a list of arguments
  57                         $args = reset( $args );
  58                 }
  59                 $command = new Command();
  60                 $config = MediaWikiServices::getInstance()->getMainConfig();
  61
  62                 $limits = [
  63                         'time' => $config->get( 'MaxShellTime' ),
  64                         'walltime' => $config->get( 'MaxShellWallClockTime' ),
  65                         'memory' => $config->get( 'MaxShellMemory' ),
  66                         'filesize' => $config->get( 'MaxShellFileSize' ),
  67                 ];
  68                 $command->limits( $limits );
  69                 $command->cgroup( $config->get( 'ShellCgroup' ) );
  70                 $command->setLogger( LoggerFactory::getInstance( 'exec' ) );
  71
  72                 return $command->params( $args );
  73         }
  74
  75         /**
  76          * Check if this class is effectively disabled via php.ini config
  77          *
  78          * @return bool
  79          */
  80         public static function isDisabled() {
  81                 static $disabled = null;
  82
  83                 if ( is_null( $disabled ) ) {
  84                         if ( !function_exists( 'proc_open' ) ) {
  85                                 wfDebug( "proc_open() is disabled\n" );
  86                                 $disabled = true;
  87                         } else {
  88                                 $disabled = false;
  89                         }
  90                 }
  91
  92                 return $disabled;
  93         }
  94
  95         /**
  96          * Version of escapeshellarg() that works better on Windows.
  97          *
  98          * Originally, this fixed the incorrect use of single quotes on Windows
  99          * (https://bugs.php.net/bug.php?id=26285) and the locale problems on Linux in
 100          * PHP 5.2.6+ (bug backported to earlier distro releases of PHP).
 101          *
 102          * @param string $args,... strings to escape and glue together, or a single array of
 103          *     strings parameter
 104          * @return string
 105          */
 106         public static function escape( /* ... */ ) {
 107                 $args = func_get_args();
 108                 if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
 109                         // If only one argument has been passed, and that argument is an array,
 110                         // treat it as a list of arguments
 111                         $args = reset( $args );
 112                 }
 113
 114                 $first = true;
 115                 $retVal = '';
 116                 foreach ( $args as $arg ) {
 117                         if ( !$first ) {
 118                                 $retVal .= ' ';
 119                         } else {
 120                                 $first = false;
 121                         }
 122
 123                         if ( wfIsWindows() ) {
 124                                 // Escaping for an MSVC-style command line parser and CMD.EXE
 125                                 // @codingStandardsIgnoreStart For long URLs
 126                                 // Refs:
 127                                 //  * https://web.archive.org/web/20020708081031/http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
 128                                 //  * https://technet.microsoft.com/en-us/library/cc723564.aspx
 129                                 //  * T15518
 130                                 //  * CR r63214
 131                                 // Double the backslashes before any double quotes. Escape the double quotes.
 132                                 // @codingStandardsIgnoreEnd
 133                                 $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
 134                                 $arg = '';
 135                                 $iteration = 0;
 136                                 foreach ( $tokens as $token ) {
 137                                         if ( $iteration % 2 == 1 ) {
 138                                                 // Delimiter, a double quote preceded by zero or more slashes
 139                                                 $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
 140                                         } elseif ( $iteration % 4 == 2 ) {
 141                                                 // ^ in $token will be outside quotes, need to be escaped
 142                                                 $arg .= str_replace( '^', '^^', $token );
 143                                         } else { // $iteration % 4 == 0
 144                                                 // ^ in $token will appear inside double quotes, so leave as is
 145                                                 $arg .= $token;
 146                                         }
 147                                         $iteration++;
 148                                 }
 149                                 // Double the backslashes before the end of the string, because
 150                                 // we will soon add a quote
 151                                 $m = [];
 152                                 if ( preg_match( '/^(.*?)(\\\\+)$/', $arg, $m ) ) {
 153                                         $arg = $m[1] . str_replace( '\\', '\\\\', $m[2] );
 154                                 }
 155
 156                                 // Add surrounding quotes
 157                                 $retVal .= '"' . $arg . '"';
 158                         } else {
 159                                 $retVal .= escapeshellarg( $arg );
 160                         }
 161                 }
 162                 return $retVal;
 163         }
 164 }