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  *  ... = $result->getStderr();
  42  */
  43 class Shell {
  44
  45         /**
  46          * Returns a new instance of Command class
  47          *
  48          * @param string|string[] $command String or array of strings representing the command to
  49          * be executed, each value will be escaped.
  50          *   Example:   [ 'convert', '-font', 'font name' ] would produce "'convert' '-font' 'font name'"
  51          * @return Command
  52          */
  53         public static function command( $command ) {
  54                 $args = func_get_args();
  55                 if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
  56                         // If only one argument has been passed, and that argument is an array,
  57                         // treat it as a list of arguments
  58                         $args = reset( $args );
  59                 }
  60                 $command = new Command();
  61                 $config = MediaWikiServices::getInstance()->getMainConfig();
  62
  63                 $limits = [
  64                         'time' => $config->get( 'MaxShellTime' ),
  65                         'walltime' => $config->get( 'MaxShellWallClockTime' ),
  66                         'memory' => $config->get( 'MaxShellMemory' ),
  67                         'filesize' => $config->get( 'MaxShellFileSize' ),
  68                 ];
  69                 $command->limits( $limits );
  70                 $command->cgroup( $config->get( 'ShellCgroup' ) );
  71                 $command->setLogger( LoggerFactory::getInstance( 'exec' ) );
  72
  73                 return $command->params( $args );
  74         }
  75
  76         /**
  77          * Check if this class is effectively disabled via php.ini config
  78          *
  79          * @return bool
  80          */
  81         public static function isDisabled() {
  82                 static $disabled = null;
  83
  84                 if ( is_null( $disabled ) ) {
  85                         if ( !function_exists( 'proc_open' ) ) {
  86                                 wfDebug( "proc_open() is disabled\n" );
  87                                 $disabled = true;
  88                         } else {
  89                                 $disabled = false;
  90                         }
  91                 }
  92
  93                 return $disabled;
  94         }
  95
  96         /**
  97          * Version of escapeshellarg() that works better on Windows.
  98          *
  99          * Originally, this fixed the incorrect use of single quotes on Windows
 100          * (https://bugs.php.net/bug.php?id=26285) and the locale problems on Linux in
 101          * PHP 5.2.6+ (bug backported to earlier distro releases of PHP).
 102          *
 103          * @param string $args,... strings to escape and glue together, or a single array of
 104          *     strings parameter
 105          * @return string
 106          */
 107         public static function escape( /* ... */ ) {
 108                 $args = func_get_args();
 109                 if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
 110                         // If only one argument has been passed, and that argument is an array,
 111                         // treat it as a list of arguments
 112                         $args = reset( $args );
 113                 }
 114
 115                 $first = true;
 116                 $retVal = '';
 117                 foreach ( $args as $arg ) {
 118                         if ( !$first ) {
 119                                 $retVal .= ' ';
 120                         } else {
 121                                 $first = false;
 122                         }
 123
 124                         if ( wfIsWindows() ) {
 125                                 // Escaping for an MSVC-style command line parser and CMD.EXE
 126                                 // @codingStandardsIgnoreStart For long URLs
 127                                 // Refs:
 128                                 //  * https://web.archive.org/web/20020708081031/http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
 129                                 //  * https://technet.microsoft.com/en-us/library/cc723564.aspx
 130                                 //  * T15518
 131                                 //  * CR r63214
 132                                 // Double the backslashes before any double quotes. Escape the double quotes.
 133                                 // @codingStandardsIgnoreEnd
 134                                 $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
 135                                 $arg = '';
 136                                 $iteration = 0;
 137                                 foreach ( $tokens as $token ) {
 138                                         if ( $iteration % 2 == 1 ) {
 139                                                 // Delimiter, a double quote preceded by zero or more slashes
 140                                                 $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
 141                                         } elseif ( $iteration % 4 == 2 ) {
 142                                                 // ^ in $token will be outside quotes, need to be escaped
 143                                                 $arg .= str_replace( '^', '^^', $token );
 144                                         } else { // $iteration % 4 == 0
 145                                                 // ^ in $token will appear inside double quotes, so leave as is
 146                                                 $arg .= $token;
 147                                         }
 148                                         $iteration++;
 149                                 }
 150                                 // Double the backslashes before the end of the string, because
 151                                 // we will soon add a quote
 152                                 $m = [];
 153                                 if ( preg_match( '/^(.*?)(\\\\+)$/', $arg, $m ) ) {
 154                                         $arg = $m[1] . str_replace( '\\', '\\\\', $m[2] );
 155                                 }
 156
 157                                 // Add surrounding quotes
 158                                 $retVal .= '"' . $arg . '"';
 159                         } else {
 160                                 $retVal .= escapeshellarg( $arg );
 161                         }
 162                 }
 163                 return $retVal;
 164         }
 165 }