Allow programmatic input in Command

Bug: T182463
Change-Id: Ib68180c7af12558686f4864c24fd85f01201d6fb

includes/shell/Command.php

@@ -56,6 +56,9 @@ class Command {
 	/** @var string */
 	private $method;
 
+	/** @var string|null */
+	private $inputString;
+
 	/** @var bool */
 	private $doIncludeStderr = false;
 
@@ -189,6 +192,18 @@ public function profileMethod( $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.
@@ -350,7 +365,7 @@ public function execute() {
 		}
 
 		$desc = [
-			0 => [ 'file', 'php://stdin', 'r' ],
+			0 => $this->inputString === null ? [ 'file', 'php://stdin', 'r' ] : [ 'pipe', 'r' ],
 			1 => [ 'pipe', 'w' ],
 			2 => [ 'pipe', 'w' ],
 		];
@@ -364,8 +379,13 @@ public function execute() {
 			$this->logger->error( "proc_open() failed: {command}", [ 'command' => $cmd ] );
 			throw new ProcOpenError();
 		}
-		$outBuffer = $logBuffer = '';
-		$errBuffer = null;
+
+		$buffers = [
+			0 => $this->inputString, // input
+			1 => '', // stdout
+			2 => null, // stderr
+			3 => '', // log
+		];
 		$emptyArray = [];
 		$status = false;
 		$logMsg = false;
@@ -399,8 +419,6 @@ public function execute() {
 				}
 			}
 
-			$readyPipes = $pipes;
-
 			// 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
@@ -410,8 +428,17 @@ public function execute() {
 			@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( $readyPipes, $emptyArray, $emptyArray, $timeout );
+			$numReadyPipes = @stream_select( $writePipes, $readPipes, $emptyArray, $timeout );
 			if ( $numReadyPipes === false ) {
 				$error = error_get_last();
 				if ( strncmp( $error['message'], $eintrMessage, strlen( $eintrMessage ) ) == 0 ) {
@@ -422,31 +449,36 @@ public function execute() {
 					break;
 				}
 			}
-			foreach ( $readyPipes as $fd => $pipe ) {
-				$block = fread( $pipe, 65536 );
-				if ( $block === '' ) {
+			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 ) {
+					$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
 					fclose( $pipes[$fd] );
 					unset( $pipes[$fd] );
 					if ( !$pipes ) {
 						break 2;
 					}
-				} elseif ( $block === false ) {
-					// Read error
-					$logMsg = "Error reading from pipe";
-					break 2;
-				} elseif ( $fd == 1 ) {
-					// From stdout
-					$outBuffer .= $block;
-				} elseif ( $fd == 2 ) {
-					// From stderr
-					$errBuffer .= $block;
-				} elseif ( $fd == 3 ) {
-					// From log FD
-					$logBuffer .= $block;
-					if ( strpos( $block, "\n" ) !== false ) {
-						$lines = explode( "\n", $logBuffer );
-						$logBuffer = array_pop( $lines );
+				} elseif ( $isWrite ) {
+					$buffers[$fd] = substr( $buffers[$fd], $res );
+				} 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 );
 						}
@@ -491,15 +523,15 @@ public function execute() {
 			$this->logger->warning( "$logMsg: {command}", [ 'command' => $cmd ] );
 		}
 
-		if ( $errBuffer && $this->doLogStderr ) {
+		if ( $buffers[2] && $this->doLogStderr ) {
 			$this->logger->error( "Error running {command}: {error}", [
 				'command' => $cmd,
-				'error' => $errBuffer,
+				'error' => $buffers[2],
 				'exitcode' => $retval,
 				'exception' => new Exception( 'Shell error' ),
 			] );
 		}
 
-		return new Result( $retval, $outBuffer, $errBuffer );
+		return new Result( $retval, $buffers[1], $buffers[2] );
 	}
 }

includes/shell/Shell.php

@@ -31,6 +31,7 @@
  *
  * Use call chaining with this class for expressiveness:
  *  $result = Shell::command( 'some command' )
+ *       ->input( 'foo' )
  *       ->environment( [ 'ENVIRONMENT_VARIABLE' => 'VALUE' ] )
  *       ->limits( [ 'time' => 300 ] )
  *       ->execute();

tests/phpunit/includes/shell/CommandTest.php

@@ -154,4 +154,21 @@ public function testLogStderr() {
 		$this->assertSame( 1, count( $logger->getBuffer() ) );
 		$this->assertSame( trim( $logger->getBuffer()[0][2]['error'] ), 'ThisIsStderr' );
 	}
+
+	public function testInput() {
+		$this->requirePosix();
+
+		$command = new Command();
+		$command->params( 'cat' );
+		$command->input( 'abc' );
+		$result = $command->execute();
+		$this->assertSame( 'abc', $result->getStdout() );
+
+		// now try it with something that does not fit into a single block
+		$command = new Command();
+		$command->params( 'cat' );
+		$command->input( str_repeat( '!', 1000000 ) );
+		$result = $command->execute();
+		$this->assertSame( 1000000, strlen( $result->getStdout() ) );
+	}
 }