Ignore chmod failures, fixes #1854

src/Composer/Command/ConfigCommand.php

@@ -117,7 +117,7 @@ EOT
         if ($input->getOption('global') && !$this->configFile->exists()) {
             touch($this->configFile->getPath());
             $this->configFile->write(array('config' => new \ArrayObject));
-            chmod($this->configFile->getPath(), 0600);
+            @chmod($this->configFile->getPath(), 0600);
         }
 
         if (!$this->configFile->exists()) {

src/Composer/Command/SelfUpdateCommand.php

@@ -72,7 +72,7 @@ EOT
             }
 
             try {
-                chmod($tempFilename, 0777 & ~umask());
+                @chmod($tempFilename, 0777 & ~umask());
                 // test the phar validity
                 $phar = new \Phar($tempFilename);
                 // free the variable to unlock the file

src/Composer/Config/JsonConfigSource.php

@@ -124,7 +124,7 @@ class JsonConfigSource implements ConfigSourceInterface
         }
 
         if ($newFile) {
-            chmod($this->file->getPath(), 0600);
+            @chmod($this->file->getPath(), 0600);
         }
     }
 }

src/Composer/Installer/LibraryInstaller.php

@@ -205,7 +205,7 @@ class LibraryInstaller implements InstallerInterface
                     // likely leftover from a previous install, make sure
                     // that the target is still executable in case this
                     // is a fresh install of the vendor.
-                    chmod($link, 0777 & ~umask());
+                    @chmod($link, 0777 & ~umask());
                 }
                 $this->io->write('    Skipped installation of '.$bin.' for package '.$package->getName().': name conflicts with an existing file');
                 continue;
@@ -214,7 +214,7 @@ class LibraryInstaller implements InstallerInterface
                 // add unixy support for cygwin and similar environments
                 if ('.bat' !== substr($binPath, -4)) {
                     file_put_contents($link, $this->generateUnixyProxyCode($binPath, $link));
-                    chmod($link, 0777 & ~umask());
+                    @chmod($link, 0777 & ~umask());
                     $link .= '.bat';
                     if (file_exists($link)) {
                         $this->io->write('    Skipped installation of '.$bin.'.bat proxy for package '.$package->getName().': a .bat proxy was already installed');
@@ -238,7 +238,7 @@ class LibraryInstaller implements InstallerInterface
                 }
                 chdir($cwd);
             }
-            chmod($link, 0777 & ~umask());
+            @chmod($link, 0777 & ~umask());
         }
     }
 

src/Composer/Installer/PearInstaller.php

@@ -99,9 +99,9 @@ class PearInstaller extends LibraryInstaller
     {
         parent::initializeBinDir();
         file_put_contents($this->binDir.'/composer-php', $this->generateUnixyPhpProxyCode());
-        chmod($this->binDir.'/composer-php', 0777);
+        @chmod($this->binDir.'/composer-php', 0777);
         file_put_contents($this->binDir.'/composer-php.bat', $this->generateWindowsPhpProxyCode());
-        chmod($this->binDir.'/composer-php.bat', 0777);
+        @chmod($this->binDir.'/composer-php.bat', 0777);
     }
 
     protected function generateWindowsProxyCode($bin, $link)