NPE in PluginsService when starting elasticsearch with a wrong user

src/main/java/org/elasticsearch/common/io/FileSystemUtils.java

@@ -228,6 +228,28 @@ public static void copyFile(File sourceFile, File destinationFile) throws IOExce
         }
     }
 
+    /**
+     * Check that a directory exists, is a directory and is readable
+     * by the current user
+     */
+    public static boolean isAccessibleDirectory(File directory, ESLogger logger) {
+        assert directory != null && logger != null;
+
+        if (!directory.exists()) {
+            logger.debug("plugins directory does not exist [{}].", directory.getAbsolutePath());
+            return false;
+        }
+        if (!directory.isDirectory()) {
+            logger.debug("plugins directory is not a directory [{}].", directory.getAbsolutePath());
+            return false;
+        }
+        if (!directory.canRead()) {
+            logger.debug("plugins directory is not readable [{}].", directory.getAbsolutePath());
+            return false;
+        }
+        return true;
+    }
+
     private FileSystemUtils() {
 
     }

src/main/java/org/elasticsearch/plugins/PluginsService.java

@@ -30,6 +30,7 @@
 import org.elasticsearch.common.component.AbstractComponent;
 import org.elasticsearch.common.component.LifecycleComponent;
 import org.elasticsearch.common.inject.Module;
+import org.elasticsearch.common.io.FileSystemUtils;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
@@ -316,11 +317,8 @@ synchronized public PluginsInfo info() {
     }
 
     private void loadPluginsIntoClassLoader() {
-        File pluginsFile = environment.pluginsFile();
-        if (!pluginsFile.exists()) {
-            return;
-        }
-        if (!pluginsFile.isDirectory()) {
+        File pluginsDirectory = environment.pluginsFile();
+        if (!FileSystemUtils.isAccessibleDirectory(pluginsDirectory, logger)) {
             return;
         }
 
@@ -342,40 +340,39 @@ private void loadPluginsIntoClassLoader() {
             return;
         }
 
-        File[] pluginsFiles = pluginsFile.listFiles();
-        if (pluginsFile != null) {
-            for (File pluginFile : pluginsFiles) {
-                if (pluginFile.isDirectory()) {
-                    if (logger.isTraceEnabled()) {
-                        logger.trace("--- adding plugin [" + pluginFile.getAbsolutePath() + "]");
-                    }
-                    try {
-                        // add the root
-                        addURL.invoke(classLoader, pluginFile.toURI().toURL());
-                        // gather files to add
-                        List<File> libFiles = Lists.newArrayList();
-                        if (pluginFile.listFiles() != null) {
-                            libFiles.addAll(Arrays.asList(pluginFile.listFiles()));
-                        }
-                        File libLocation = new File(pluginFile, "lib");
-                        if (libLocation.exists() && libLocation.isDirectory() && libLocation.listFiles() != null) {
-                            libFiles.addAll(Arrays.asList(libLocation.listFiles()));
-                        }
+        for (File plugin : pluginsDirectory.listFiles()) {
+            // We check that subdirs are directories and readable
+            if (!FileSystemUtils.isAccessibleDirectory(plugin, logger)) {
+                continue;
+            }
 
-                        // if there are jars in it, add it as well
-                        for (File libFile : libFiles) {
-                            if (!(libFile.getName().endsWith(".jar") || libFile.getName().endsWith(".zip"))) {
-                                continue;
-                            }
-                            addURL.invoke(classLoader, libFile.toURI().toURL());
-                        }
-                    } catch (Throwable e) {
-                        logger.warn("failed to add plugin [" + pluginFile + "]", e);
+            if (logger.isTraceEnabled()) {
+                logger.trace("--- adding plugin [{}]", plugin.getAbsolutePath());
+            }
+
+            try {
+                // add the root
+                addURL.invoke(classLoader, plugin.toURI().toURL());
+                // gather files to add
+                List<File> libFiles = Lists.newArrayList();
+                if (plugin.listFiles() != null) {
+                    libFiles.addAll(Arrays.asList(plugin.listFiles()));
+                }
+                File libLocation = new File(plugin, "lib");
+                if (libLocation.exists() && libLocation.isDirectory() && libLocation.listFiles() != null) {
+                    libFiles.addAll(Arrays.asList(libLocation.listFiles()));
+                }
+
+                // if there are jars in it, add it as well
+                for (File libFile : libFiles) {
+                    if (!(libFile.getName().endsWith(".jar") || libFile.getName().endsWith(".zip"))) {
+                        continue;
                     }
+                    addURL.invoke(classLoader, libFile.toURI().toURL());
                 }
+            } catch (Throwable e) {
+                logger.warn("failed to add plugin [" + plugin + "]", e);
             }
-        } else {
-            logger.debug("failed to list plugins from {}. Check your right access.", pluginsFile.getAbsolutePath());
         }
     }