wikimedia/mediawiki-core

<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

namespace MediaWiki\Shell;

use Exception;
use MediaWiki\ShellDisabledError;
use Profiler;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use Shellbox\Command\UnboxedCommand;
use Shellbox\Command\UnboxedExecutor;
use Shellbox\Command\UnboxedResult;
use Stringable;
use Wikimedia\ScopedCallback;

/**
 * Class used for executing shell commands
 *
 * @since 1.30
 */
class Command extends UnboxedCommand implements Stringable {
    private bool $everExecuted = false;

    /** @var string */
    private $method;

    protected LoggerInterface $logger;

    /**
     * Don't call directly, instead use Shell::command()
     *
     * @param UnboxedExecutor $executor
     * @throws ShellDisabledError
     */
    public function __construct( UnboxedExecutor $executor ) {
        if ( Shell::isDisabled() ) {
            throw new ShellDisabledError();
        }
        parent::__construct( $executor );
        $this->setLogger( new NullLogger() );
    }

    /**
     * Makes sure the programmer didn't forget to execute the command after all
     */
    public function __destruct() {
        if ( !$this->everExecuted ) {
            $context = [ 'command' => $this->getCommandString() ];
            $message = __CLASS__ . " was instantiated, but execute() was never called.";
            if ( $this->method ) {
                $message .= ' Calling method: {method}.';
                $context['method'] = $this->method;
            }
            $message .= ' Command: {command}';
            $this->logger->warning( $message, $context );
        }
    }

    /**
     * @param LoggerInterface $logger
     */
    public function setLogger( LoggerInterface $logger ) {
        $this->logger = $logger;
        if ( $this->executor ) {
            $this->executor->setLogger( $logger );
        }
    }

    /**
     * Sets execution limits
     *
     * @param array $limits Associative array of limits. Keys (all optional):
     *   filesize (for ulimit -f), memory, time, walltime.
     * @return $this
     */
    public function limits( array $limits ): Command {
        if ( !isset( $limits['walltime'] ) && isset( $limits['time'] ) ) {
            // Emulate the behavior of old wfShellExec() where walltime fell back on time
            // if the latter was overridden and the former wasn't
            $limits['walltime'] = $limits['time'];
        }
        if ( isset( $limits['filesize'] ) ) {
            $this->fileSizeLimit( $limits['filesize'] * 1024 );
        }
        if ( isset( $limits['memory'] ) ) {
            $this->memoryLimit( $limits['memory'] * 1024 );
        }
        if ( isset( $limits['time'] ) ) {
            $this->cpuTimeLimit( $limits['time'] );
        }
        if ( isset( $limits['walltime'] ) ) {
            $this->wallTimeLimit( $limits['walltime'] );
        }

        return $this;
    }

    /**
     * Sets calling function for profiler. By default, the caller for execute() will be used.
     *
     * @param string $method
     * @return $this
     */
    public function profileMethod( string $method ): Command {
        $this->method = $method;

        return $this;
    }

    /**
     * Sends the provided input to the command. Defaults to an empty string.
     * If you want to pass stdin through to the command instead, use
     * passStdin().
     *
     * @param string $inputString
     * @return $this
     */
    public function input( string $inputString ): Command {
        return $this->stdin( $inputString );
    }

    /**
     * Set restrictions for this request, overwriting any previously set restrictions.
     *
     * Add the "no network" restriction:
     * @code
     *     $command->restrict( Shell::RESTRICT_DEFAULT | Shell::NO_NETWORK );
     * @endcode
     *
     * Allow LocalSettings.php access:
     * @code
     *     $command->restrict( Shell::RESTRICT_DEFAULT & ~Shell::NO_LOCALSETTINGS );
     * @endcode
     *
     * Disable all restrictions:
     * @code
     *  $command->restrict( Shell::RESTRICT_NONE );
     * @endcode
     *
     * @deprecated since 1.36 Set the options using their separate accessors
     *
     * @since 1.31
     * @param int $restrictions
     * @return $this
     */
    public function restrict( int $restrictions ): Command {
        $this->privateUserNamespace( (bool)( $restrictions & Shell::NO_ROOT ) );
        $this->firejailDefaultSeccomp( (bool)( $restrictions & Shell::SECCOMP ) );
        $this->noNewPrivs( (bool)( $restrictions & Shell::SECCOMP ) );
        $this->privateDev( (bool)( $restrictions & Shell::PRIVATE_DEV ) );
        $this->disableNetwork( (bool)( $restrictions & Shell::NO_NETWORK ) );
        if ( $restrictions & Shell::NO_EXECVE ) {
            $this->disabledSyscalls( [ 'execve' ] );
        } else {
            $this->disabledSyscalls( [] );
        }
        if ( $restrictions & Shell::NO_LOCALSETTINGS ) {
            $this->disallowedPaths( [ realpath( MW_CONFIG_FILE ) ] );
        } else {
            $this->disallowedPaths( [] );
        }
        if ( $restrictions === 0 ) {
            $this->disableSandbox();
        }

        return $this;
    }

    /**
     * If called, only the files/directories that are
     * whitelisted will be available to the shell command.
     *
     * limit.sh will always be whitelisted
     *
     * @deprecated since 1.36 Use allowPath/disallowPath. Hard
     *   deprecated in 1.40 and to be removed in 1.41
     * @param string[] $paths
     * @return $this
     */
    public function whitelistPaths( array $paths ): Command {
        wfDeprecated( __METHOD__, '1.36' );
        $this->allowedPaths( array_merge( $this->getAllowedPaths(), $paths ) );
        return $this;
    }

    /**
     * Executes command. Afterwards, getExitCode() and getOutput() can be used to access execution
     * results.
     *
     * @return UnboxedResult
     * @throws Exception
     */
    public function execute(): UnboxedResult {
        $this->everExecuted = true;
        $profileMethod = $this->method ?: wfGetCaller();
        $scoped = Profiler::instance()->scopedProfileIn( __FUNCTION__ . '-' . $profileMethod );
        $result = parent::execute();
        ScopedCallback::consume( $scoped );
        return $result;
    }

    /**
     * Returns the final command line before environment/limiting, etc are applied.
     * Use string conversion only for debugging, don't try to pass this to
     * some other execution medium.
     *
     * @return string
     */
    public function __toString(): string {
        return '#Command: ' . $this->getCommandString();
    }
}