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+<?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\ProcOpenError;
+use MediaWiki\ShellDisabledError;
+use Profiler;
+use Psr\Log\LoggerAwareTrait;
+use Psr\Log\NullLogger;
+
+/**
+ * Class used for executing shell commands
+ *
+ * @since 1.30
+ */
+class Command {
+ use LoggerAwareTrait;
+
+ /** @var string */
+ protected $command = '';
+
+ /** @var array */
+ private $limits = [
+ // seconds
+ 'time' => 180,
+ // seconds
+ 'walltime' => 180,
+ // KB
+ 'memory' => 307200,
+ // KB
+ 'filesize' => 102400,
+ ];
+
+ /** @var string[] */
+ private $env = [];
+
+ /** @var string */
+ private $method;
+
+ /** @var string|null */
+ private $inputString;
+
+ /** @var bool */
+ private $doIncludeStderr = false;
+
+ /** @var bool */
+ private $doLogStderr = false;
+
+ /** @var bool */
+ private $everExecuted = false;
+
+ /** @var string|false */
+ private $cgroup = false;
+
+ /**
+ * bitfield with restrictions
+ *
+ * @var int
+ */
+ protected $restrictions = 0;
+
+ /**
+ * Constructor. Don't call directly, instead use Shell::command()
+ *
+ * @throws ShellDisabledError
+ */
+ public function __construct() {
+ if ( Shell::isDisabled() ) {
+ throw new ShellDisabledError();
+ }
+
+ $this->setLogger( new NullLogger() );
+ }
+
+ /**
+ * Destructor. Makes sure programmer didn't forget to execute the command after all
+ */
+ public function __destruct() {
+ if ( !$this->everExecuted ) {
+ $context = [ 'command' => $this->command ];
+ $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 );
+ }
+ }
+
+ /**
+ * Adds parameters to the command. All parameters are sanitized via Shell::escape().
+ * Null values are ignored.
+ *
+ * @param string|string[] $args,...
+ * @return $this
+ */
+ public function params( /* ... */ ) {
+ $args = func_get_args();
+ if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
+ // If only one argument has been passed, and that argument is an array,
+ // treat it as a list of arguments
+ $args = reset( $args );
+ }
+ $this->command = trim( $this->command . ' ' . Shell::escape( $args ) );
+
+ return $this;
+ }
+
+ /**
+ * Adds unsafe parameters to the command. These parameters are NOT sanitized in any way.
+ * Null values are ignored.
+ *
+ * @param string|string[] $args,...
+ * @return $this
+ */
+ public function unsafeParams( /* ... */ ) {
+ $args = func_get_args();
+ if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
+ // If only one argument has been passed, and that argument is an array,
+ // treat it as a list of arguments
+ $args = reset( $args );
+ }
+ $args = array_filter( $args,
+ function ( $value ) {
+ return $value !== null;
+ }
+ );
+ $this->command = trim( $this->command . ' ' . implode( ' ', $args ) );
+
+ return $this;
+ }
+
+ /**
+ * 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 ) {
+ 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'];
+ }
+ $this->limits = $limits + $this->limits;
+
+ return $this;
+ }
+
+ /**
+ * Sets environment variables which should be added to the executed command environment
+ *
+ * @param string[] $env array of variable name => value
+ * @return $this
+ */
+ public function environment( array $env ) {
+ $this->env = $env;
+
+ return $this;
+ }
+
+ /**
+ * Sets calling function for profiler. By default, the caller for execute() will be used.
+ *
+ * @param string $method
+ * @return $this
+ */
+ public function profileMethod( $method ) {
+ $this->method = $method;
+
+ return $this;
+ }
+
+ /**
+ * Sends the provided input to the command.
+ * When set to null (default), the command will use the standard input.
+ * @param string|null $inputString
+ * @return $this
+ */
+ public function input( $inputString ) {
+ $this->inputString = is_null( $inputString ) ? null : (string)$inputString;
+
+ return $this;
+ }
+
+ /**
+ * Controls whether stderr should be included in stdout, including errors from limit.sh.
+ * Default: don't include.
+ *
+ * @param bool $yesno
+ * @return $this
+ */
+ public function includeStderr( $yesno = true ) {
+ $this->doIncludeStderr = $yesno;
+
+ return $this;
+ }
+
+ /**
+ * When enabled, text sent to stderr will be logged with a level of 'error'.
+ *
+ * @param bool $yesno
+ * @return $this
+ */
+ public function logStderr( $yesno = true ) {
+ $this->doLogStderr = $yesno;
+
+ return $this;
+ }
+
+ /**
+ * Sets cgroup for this command
+ *
+ * @param string|false $cgroup Absolute file path to the cgroup, or false to not use a cgroup
+ * @return $this
+ */
+ public function cgroup( $cgroup ) {
+ $this->cgroup = $cgroup;
+
+ return $this;
+ }
+
+ /**
+ * Set additional restrictions for this request
+ *
+ * @since 1.31
+ * @param int $restrictions
+ * @return $this
+ */
+ public function restrict( $restrictions ) {
+ $this->restrictions |= $restrictions;
+
+ return $this;
+ }
+
+ /**
+ * Bitfield helper on whether a specific restriction is enabled
+ *
+ * @param int $restriction
+ *
+ * @return bool
+ */
+ protected function hasRestriction( $restriction ) {
+ return ( $this->restrictions & $restriction ) === $restriction;
+ }
+
+ /**
+ * If called, only the files/directories that are
+ * whitelisted will be available to the shell command.
+ *
+ * limit.sh will always be whitelisted
+ *
+ * @param string[] $paths
+ *
+ * @return $this
+ */
+ public function whitelistPaths( array $paths ) {
+ // Default implementation is a no-op
+ return $this;
+ }
+
+ /**
+ * String together all the options and build the final command
+ * to execute
+ *
+ * @param string $command Already-escaped command to run
+ * @return array [ command, whether to use log pipe ]
+ */
+ protected function buildFinalCommand( $command ) {
+ $envcmd = '';
+ foreach ( $this->env as $k => $v ) {
+ if ( wfIsWindows() ) {
+ /* Surrounding a set in quotes (method used by wfEscapeShellArg) makes the quotes themselves
+ * appear in the environment variable, so we must use carat escaping as documented in
+ * https://technet.microsoft.com/en-us/library/cc723564.aspx
+ * Note however that the quote isn't listed there, but is needed, and the parentheses
+ * are listed there but doesn't appear to need it.
+ */
+ $envcmd .= "set $k=" . preg_replace( '/([&|()<>^"])/', '^\\1', $v ) . '&& ';
+ } else {
+ /* Assume this is a POSIX shell, thus required to accept variable assignments before the command
+ * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_09_01
+ */
+ $envcmd .= "$k=" . escapeshellarg( $v ) . ' ';
+ }
+ }
+
+ $useLogPipe = false;
+ $cmd = $envcmd . trim( $command );
+
+ if ( is_executable( '/bin/bash' ) ) {
+ $time = intval( $this->limits['time'] );
+ $wallTime = intval( $this->limits['walltime'] );
+ $mem = intval( $this->limits['memory'] );
+ $filesize = intval( $this->limits['filesize'] );
+
+ if ( $time > 0 || $mem > 0 || $filesize > 0 || $wallTime > 0 ) {
+ $cmd = '/bin/bash ' . escapeshellarg( __DIR__ . '/limit.sh' ) . ' ' .
+ escapeshellarg( $cmd ) . ' ' .
+ escapeshellarg(
+ "MW_INCLUDE_STDERR=" . ( $this->doIncludeStderr ? '1' : '' ) . ';' .
+ "MW_CPU_LIMIT=$time; " .
+ 'MW_CGROUP=' . escapeshellarg( $this->cgroup ) . '; ' .
+ "MW_MEM_LIMIT=$mem; " .
+ "MW_FILE_SIZE_LIMIT=$filesize; " .
+ "MW_WALL_CLOCK_LIMIT=$wallTime; " .
+ "MW_USE_LOG_PIPE=yes"
+ );
+ $useLogPipe = true;
+ }
+ }
+ if ( !$useLogPipe && $this->doIncludeStderr ) {
+ $cmd .= ' 2>&1';
+ }
+
+ return [ $cmd, $useLogPipe ];
+ }
+
+ /**
+ * Executes command. Afterwards, getExitCode() and getOutput() can be used to access execution
+ * results.
+ *
+ * @return Result
+ * @throws Exception
+ * @throws ProcOpenError
+ * @throws ShellDisabledError
+ */
+ public function execute() {
+ $this->everExecuted = true;
+
+ $profileMethod = $this->method ?: wfGetCaller();
+
+ list( $cmd, $useLogPipe ) = $this->buildFinalCommand( $this->command );
+
+ $this->logger->debug( __METHOD__ . ": $cmd" );
+
+ // Don't try to execute commands that exceed Linux's MAX_ARG_STRLEN.
+ // Other platforms may be more accomodating, but we don't want to be
+ // accomodating, because very long commands probably include user
+ // input. See T129506.
+ if ( strlen( $cmd ) > SHELL_MAX_ARG_STRLEN ) {
+ throw new Exception( __METHOD__ .
+ '(): total length of $cmd must not exceed SHELL_MAX_ARG_STRLEN' );
+ }
+
+ $desc = [
+ 0 => $this->inputString === null ? [ 'file', 'php://stdin', 'r' ] : [ 'pipe', 'r' ],
+ 1 => [ 'pipe', 'w' ],
+ 2 => [ 'pipe', 'w' ],
+ ];
+ if ( $useLogPipe ) {
+ $desc[3] = [ 'pipe', 'w' ];
+ }
+ $pipes = null;
+ $scoped = Profiler::instance()->scopedProfileIn( __FUNCTION__ . '-' . $profileMethod );
+ $proc = proc_open( $cmd, $desc, $pipes );
+ if ( !$proc ) {
+ $this->logger->error( "proc_open() failed: {command}", [ 'command' => $cmd ] );
+ throw new ProcOpenError();
+ }
+
+ $buffers = [
+ 0 => $this->inputString, // input
+ 1 => '', // stdout
+ 2 => null, // stderr
+ 3 => '', // log
+ ];
+ $emptyArray = [];
+ $status = false;
+ $logMsg = false;
+
+ /* According to the documentation, it is possible for stream_select()
+ * to fail due to EINTR. I haven't managed to induce this in testing
+ * despite sending various signals. If it did happen, the error
+ * message would take the form:
+ *
+ * stream_select(): unable to select [4]: Interrupted system call (max_fd=5)
+ *
+ * where [4] is the value of the macro EINTR and "Interrupted system
+ * call" is string which according to the Linux manual is "possibly"
+ * localised according to LC_MESSAGES.
+ */
+ $eintr = defined( 'SOCKET_EINTR' ) ? SOCKET_EINTR : 4;
+ $eintrMessage = "stream_select(): unable to select [$eintr]";
+
+ /* The select(2) system call only guarantees a "sufficiently small write"
+ * can be made without blocking. And on Linux the read might block too
+ * in certain cases, although I don't know if any of them can occur here.
+ * Regardless, set all the pipes to non-blocking to avoid T184171.
+ */
+ foreach ( $pipes as $pipe ) {
+ stream_set_blocking( $pipe, false );
+ }
+
+ $running = true;
+ $timeout = null;
+ $numReadyPipes = 0;
+
+ while ( $pipes && ( $running === true || $numReadyPipes !== 0 ) ) {
+ if ( $running ) {
+ $status = proc_get_status( $proc );
+ // If the process has terminated, switch to nonblocking selects
+ // for getting any data still waiting to be read.
+ if ( !$status['running'] ) {
+ $running = false;
+ $timeout = 0;
+ }
+ }
+
+ // clear get_last_error without actually raising an error
+ // from http://php.net/manual/en/function.error-get-last.php#113518
+ // TODO replace with clear_last_error when requirements are bumped to PHP7
+ set_error_handler( function () {
+ }, 0 );
+ // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
+ @trigger_error( '' );
+ restore_error_handler();
+
+ $readPipes = wfArrayFilterByKey( $pipes, function ( $fd ) use ( $desc ) {
+ return $desc[$fd][0] === 'pipe' && $desc[$fd][1] === 'r';
+ } );
+ $writePipes = wfArrayFilterByKey( $pipes, function ( $fd ) use ( $desc ) {
+ return $desc[$fd][0] === 'pipe' && $desc[$fd][1] === 'w';
+ } );
+ // stream_select parameter names are from the POV of us being able to do the operation;
+ // proc_open desriptor types are from the POV of the process doing it.
+ // So $writePipes is passed as the $read parameter and $readPipes as $write.
+ // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
+ $numReadyPipes = @stream_select( $writePipes, $readPipes, $emptyArray, $timeout );
+ if ( $numReadyPipes === false ) {
+ $error = error_get_last();
+ if ( strncmp( $error['message'], $eintrMessage, strlen( $eintrMessage ) ) == 0 ) {
+ continue;
+ } else {
+ trigger_error( $error['message'], E_USER_WARNING );
+ $logMsg = $error['message'];
+ break;
+ }
+ }
+ foreach ( $writePipes + $readPipes as $fd => $pipe ) {
+ // True if a pipe is unblocked for us to write into, false if for reading from
+ $isWrite = array_key_exists( $fd, $readPipes );
+
+ if ( $isWrite ) {
+ // Don't bother writing if the buffer is empty
+ if ( $buffers[$fd] === '' ) {
+ fclose( $pipes[$fd] );
+ unset( $pipes[$fd] );
+ continue;
+ }
+ $res = fwrite( $pipe, $buffers[$fd], 65536 );
+ } else {
+ $res = fread( $pipe, 65536 );
+ }
+
+ if ( $res === false ) {
+ $logMsg = 'Error ' . ( $isWrite ? 'writing to' : 'reading from' ) . ' pipe';
+ break 2;
+ }
+
+ if ( $res === '' || $res === 0 ) {
+ // End of file?
+ if ( feof( $pipe ) ) {
+ fclose( $pipes[$fd] );
+ unset( $pipes[$fd] );
+ }
+ } elseif ( $isWrite ) {
+ $buffers[$fd] = (string)substr( $buffers[$fd], $res );
+ if ( $buffers[$fd] === '' ) {
+ fclose( $pipes[$fd] );
+ unset( $pipes[$fd] );
+ }
+ } else {
+ $buffers[$fd] .= $res;
+ if ( $fd === 3 && strpos( $res, "\n" ) !== false ) {
+ // For the log FD, every line is a separate log entry.
+ $lines = explode( "\n", $buffers[3] );
+ $buffers[3] = array_pop( $lines );
+ foreach ( $lines as $line ) {
+ $this->logger->info( $line );
+ }
+ }
+ }
+ }
+ }
+
+ foreach ( $pipes as $pipe ) {
+ fclose( $pipe );
+ }
+
+ // Use the status previously collected if possible, since proc_get_status()
+ // just calls waitpid() which will not return anything useful the second time.
+ if ( $running ) {
+ $status = proc_get_status( $proc );
+ }
+
+ if ( $logMsg !== false ) {
+ // Read/select error
+ $retval = -1;
+ proc_close( $proc );
+ } elseif ( $status['signaled'] ) {
+ $logMsg = "Exited with signal {$status['termsig']}";
+ $retval = 128 + $status['termsig'];
+ proc_close( $proc );
+ } else {
+ if ( $status['running'] ) {
+ $retval = proc_close( $proc );
+ } else {
+ $retval = $status['exitcode'];
+ proc_close( $proc );
+ }
+ if ( $retval == 127 ) {
+ $logMsg = "Possibly missing executable file";
+ } elseif ( $retval >= 129 && $retval <= 192 ) {
+ $logMsg = "Probably exited with signal " . ( $retval - 128 );
+ }
+ }
+
+ if ( $logMsg !== false ) {
+ $this->logger->warning( "$logMsg: {command}", [ 'command' => $cmd ] );
+ }
+
+ if ( $buffers[2] && $this->doLogStderr ) {
+ $this->logger->error( "Error running {command}: {error}", [
+ 'command' => $cmd,
+ 'error' => $buffers[2],
+ 'exitcode' => $retval,
+ 'exception' => new Exception( 'Shell error' ),
+ ] );
+ }
+
+ return new Result( $retval, $buffers[1], $buffers[2] );
+ }
+}
generated by cgit v1.2.1 (git 2.18.0) at 2024-05-04 22:23:29 +0000