From d574e5fcab8116f397158808780f8505aa8faaad Mon Sep 17 00:00:00 2001
From: Phansys <phansys@gmail.com>
Date: Fri, 10 May 2013 22:37:30 -0300
Subject: [PATCH 1/2] Added FilesystemException to handle errors on local
 filesystem.

---
 .../Downloader/FilesystemException.php        | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 src/Composer/Downloader/FilesystemException.php

diff --git a/src/Composer/Downloader/FilesystemException.php b/src/Composer/Downloader/FilesystemException.php
new file mode 100644
index 000000000..9829b7d4a
--- /dev/null
+++ b/src/Composer/Downloader/FilesystemException.php
@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Downloader;
+
+/**
+ * Exception thrown when issues exist on local filesystem
+ * 
+ * @author Javier Spagnoletti <jspagnoletti@javierspagnoletti.com.ar>
+ */
+class FilesystemException extends \Exception
+{
+    public function __construct($message = null, $code = null, \Exception $previous = null)
+    {
+        parent::__construct("Filesystem exception: \n".$message, $code, $previous);
+    }
+}

From b992c29eb5ce106b9746d7e606e967f738f0058f Mon Sep 17 00:00:00 2001
From: Phansys <phansys@gmail.com>
Date: Fri, 10 May 2013 22:39:31 -0300
Subject: [PATCH 2/2] Added earlier permission checks in local filesystem
 before start download.

---
 src/Composer/Command/SelfUpdateCommand.php | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/Composer/Command/SelfUpdateCommand.php b/src/Composer/Command/SelfUpdateCommand.php
index 82f11af92..5358af43a 100644
--- a/src/Composer/Command/SelfUpdateCommand.php
+++ b/src/Composer/Command/SelfUpdateCommand.php
@@ -14,6 +14,7 @@ namespace Composer\Command;
 
 use Composer\Composer;
 use Composer\Util\RemoteFilesystem;
+use Composer\Downloader\FilesystemException;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 
@@ -41,6 +42,18 @@ EOT
 
     protected function execute(InputInterface $input, OutputInterface $output)
     {
+        $localFilename = realpath($_SERVER['argv'][0]) ?: $_SERVER['argv'][0];
+        $tempFilename = dirname($localFilename) . '/' . basename($localFilename, '.phar').'-temp.phar';
+        
+        // check for permissions in local filesystem before start connection process
+        if (!is_writable($tempDirectory = dirname($tempFilename))) {
+            throw new FilesystemException('Composer update failed: the "'.$tempDirectory.'" directory used to download the temp file could not be written');
+        }
+        
+        if (!is_writable($localFilename)) {
+            throw new FilesystemException('Composer update failed: the "'.$localFilename. '" file could not be written');
+        }
+        
         $protocol = extension_loaded('openssl') ? 'https' : 'http';
         $rfs = new RemoteFilesystem($this->getIO());
         $latest = trim($rfs->getContents('getcomposer.org', $protocol . '://getcomposer.org/version', false));
@@ -48,9 +61,7 @@ EOT
         if (Composer::VERSION !== $latest) {
             $output->writeln(sprintf("Updating to version <info>%s</info>.", $latest));
 
-            $remoteFilename = $protocol . '://getcomposer.org/composer.phar';
-            $localFilename = realpath($_SERVER['argv'][0]) ?: $_SERVER['argv'][0];
-            $tempFilename = dirname($localFilename) . '/' . basename($localFilename, '.phar').'-temp.phar';
+            $remoteFilename = $protocol . '://getcomposer.org/composer.phar';            
 
             $rfs->copy('getcomposer.org', $remoteFilename, $tempFilename);