Improve running of external commands

Signed-off-by: Florian Pritz <bluewind@xinu.at>

1 files changed, 129 insertions, 0 deletions

diff --git a/application/libraries/ProcRunner.php b/application/libraries/ProcRunner.php
new file mode 100644
index 000000000..6aaaa1f20
--- /dev/null
+++ b/application/libraries/ProcRunner.php
@@ -0,0 +1,129 @@
+<?php
+/*
+ * Copyright 2015 Florian "Bluewind" Pritz <bluewind@server-speed.net>
+ *
+ * Licensed under AGPLv3
+ * (see COPYING for full license text)
+ *
+ */
+
+namespace libraries;
+
+class ProcRunner {
+	private $cmd;
+	private $input = NULL;
+	private $forbid_nonzero = false;
+	private $forbid_stderr = false;
+
+	/**
+	 * This function automatically escapes all parameters before executing the command.
+	 *
+	 * @param cmd array with the command and it's arguments
+	 */
+	function __construct($cmd)
+	{
+		assert(is_array($cmd));
+		$this->cmd = implode(" ", array_map('escapeshellarg', $cmd));
+	}
+
+	/**
+	 * Set stdin. You will have to set this to NULL if you call exec() a second
+	 * time and don't want stdin to be sent again
+	 *
+	 * @param input string to send via stdin
+	 */
+	function input($input)
+	{
+		$this->input = $input;
+		return $this;
+	}
+
+	function forbid_nonzero()
+	{
+		$this->forbid_nonzero = true;
+		return $this;
+	}
+
+
+	function forbid_stderr()
+	{
+		$this->forbid_stderr = true;
+		return $this;
+	}
+
+	/**
+	 * Run the command.
+	 *
+	 * @return array with keys return_code, stdout, stderr
+	 */
+	function exec()
+	{
+		$descriptorspec = array(
+			1 => array('pipe', 'w'),
+			2 => array('pipe', 'w'),
+		);
+
+		if ($this->input !== NULL) {
+			$descriptorspec[0] = array('pipe', 'r');
+		}
+
+		$proc = proc_open($this->cmd, $descriptorspec, $pipes);
+
+		if ($proc === false) {
+			throw new \exceptions\ApiException('procrunner/proc_open-failed',
+				'Failed to run process',
+				array($this->cmd, $this->input)
+			);
+		}
+
+		if ($this->input !== NULL) {
+			fwrite($pipes[0], $this->input);
+			fclose($pipes[0]);
+		}
+
+		$stdout = stream_get_contents($pipes[1]);
+		fclose($pipes[1]);
+		assert($stdout !== false);
+
+		$stderr = stream_get_contents($pipes[2]);
+		fclose($pipes[2]);
+		assert($stderr !== false);
+
+		$return_code = proc_close($proc);
+
+		$ret = array(
+			"return_code" => $return_code,
+			"stdout" => $stdout,
+			"stderr" => $stderr,
+		);
+
+		if ($this->forbid_nonzero && $return_code !== 0) {
+			throw new \exceptions\ApiException('procrunner/non-zero-exit',
+				'Process exited with a non-zero status',
+				array($this->cmd, $this->input, $ret)
+			);
+		}
+
+		if ($this->forbid_stderr && $stderr !== "") {
+			throw new \exceptions\ApiException('procrunner/stderr',
+				'Output on stderr not allowed but received',
+				array($this->cmd, $this->input, $ret)
+			);
+		}
+
+		return $ret;
+	}
+
+	/**
+	 * Run the command and enable some sanity checks such as empty stderr and
+	 * zero exit status. Might enable more in the future.
+	 *
+	 * @See exec
+	 */
+	function execSafe()
+	{
+		$this->forbid_stderr();
+		$this->forbid_nonzero();
+		return $this->exec();
+	}
+}