Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / server / handler / AllowSymLinkAliasChecker.java

diff --git a/lib/jetty/org/eclipse/jetty/server/handler/AllowSymLinkAliasChecker.java b/lib/jetty/org/eclipse/jetty/server/handler/AllowSymLinkAliasChecker.java
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index 0000000..c3d8b59
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+++ b/lib/jetty/org/eclipse/jetty/server/handler/AllowSymLinkAliasChecker.java
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+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.server.handler;
+
+import java.io.File;
+import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.eclipse.jetty.server.handler.ContextHandler.AliasCheck;
+import org.eclipse.jetty.util.log.Log;
+import org.eclipse.jetty.util.log.Logger;
+import org.eclipse.jetty.util.resource.Resource;
+
+
+/* ------------------------------------------------------------ */
+/** Symbolic Link AliasChecker.
+ * <p>An instance of this class can be registered with {@link ContextHandler#addAliasCheck(AliasCheck)}
+ * to check resources that are aliased to other locations.   The checker uses the 
+ * Java {@link Files#readSymbolicLink(Path)} and {@link Path#toRealPath(java.nio.file.LinkOption...)}
+ * APIs to check if a file is aliased with symbolic links.</p>
+ */
+public class AllowSymLinkAliasChecker implements AliasCheck
+{
+    private static final Logger LOG = Log.getLogger(AllowSymLinkAliasChecker.class);
+    
+    @Override
+    public boolean check(String path, Resource resource)
+    {
+        try
+        {
+            File file =resource.getFile();
+            if (file==null)
+                return false;
+            
+            // If the file exists
+            if (file.exists())
+            {
+                // we can use the real path method to check the symlinks resolve to the alias
+                URI real = file.toPath().toRealPath().toUri();
+                if (real.equals(resource.getAlias()))
+                {
+                    LOG.debug("Allow symlink {} --> {}",resource,real);
+                    return true;
+                }
+            }
+            else
+            {
+                // file does not exists, so we have to walk the path and links ourselves.
+                Path p = file.toPath().toAbsolutePath();
+                File d = p.getRoot().toFile();
+                for (Path e:p)
+                {
+                    d=new File(d,e.toString());
+                    
+                    while (d.exists() && Files.isSymbolicLink(d.toPath()))
+                    {
+                        Path link=Files.readSymbolicLink(d.toPath());
+                        if (!link.isAbsolute())
+                            link=link.resolve(d.toPath());
+                        d=link.toFile().getAbsoluteFile().getCanonicalFile();
+                    }
+                }
+                if (resource.getAlias().equals(d.toURI()))
+                {
+                    LOG.debug("Allow symlink {} --> {}",resource,d);
+                    return true;
+                }
+            }
+        }
+        catch(Exception e)
+        {
+            e.printStackTrace();
+            LOG.ignore(e);
+        }
+        return false;
+    }
+
+}