install: check file/directory permissions for Shaarli resources

Relates to #40
Relates to #372

Additions:
 - FileUtils: IOException
 - ApplicationUtils:
   - check if Shaarli resources are accessible with sufficient permissions
   - basic test coverage
 - index.php:
   - check access permissions and redirect to an error page if needed:
     - before running the first installation

Modifications:
 - LinkDB:
   - factorize datastore write code
   - check if the datastore
     (exists AND is writeable) OR (doesn't exist AND its parent dir is writable)
   - raise an IOException if needed

Signed-off-by: VirtualTam <virtualtam@flibidi.net>

1 files changed, 69 insertions, 0 deletions

diff --git a/application/ApplicationUtils.php b/application/ApplicationUtils.php
new file mode 100644
index 00000000..6fb07f36
--- /dev/null
+++ b/application/ApplicationUtils.php
@@ -0,0 +1,69 @@
+<?php
+/**
+ * Shaarli (application) utilities
+ */
+class ApplicationUtils
+{
+
+    /**
+     * Checks Shaarli has the proper access permissions to its resources
+     *
+     * @param array $globalConfig The $GLOBALS['config'] array
+     *
+     * @return array A list of the detected configuration issues
+     */
+    public static function checkResourcePermissions($globalConfig)
+    {
+        $errors = array();
+
+        // Check script and template directories are readable
+        foreach (array(
+            'application',
+            'inc',
+            'plugins',
+            $globalConfig['RAINTPL_TPL']
+        ) as $path) {
+            if (! is_readable(realpath($path))) {
+                $errors[] = '"'.$path.'" directory is not readable';
+            }
+        }
+
+        // Check cache and data directories are readable and writeable
+        foreach (array(
+            $globalConfig['CACHEDIR'],
+            $globalConfig['DATADIR'],
+            $globalConfig['PAGECACHE'],
+            $globalConfig['RAINTPL_TMP']
+        ) as $path) {
+            if (! is_readable(realpath($path))) {
+                $errors[] = '"'.$path.'" directory is not readable';
+            }
+            if (! is_writable(realpath($path))) {
+                $errors[] = '"'.$path.'" directory is not writable';
+            }
+        }
+
+        // Check configuration files are readable and writeable
+        foreach (array(
+            $globalConfig['CONFIG_FILE'],
+            $globalConfig['DATASTORE'],
+            $globalConfig['IPBANS_FILENAME'],
+            $globalConfig['LOG_FILE'],
+            $globalConfig['UPDATECHECK_FILENAME']
+        ) as $path) {
+            if (! is_file(realpath($path))) {
+                # the file may not exist yet
+                continue;
+            }
+
+            if (! is_readable(realpath($path))) {
+                $errors[] = '"'.$path.'" file is not readable';
+            }
+            if (! is_writable(realpath($path))) {
+                $errors[] = '"'.$path.'" file is not writable';
+            }
+        }
+
+        return $errors;
+    }
+}