gerrit-httpd/src/main/java/com/google/gerrit/httpd/gitweb/GitWebServlet.java - gerrit - Git at Google

 // Copyright (C) 2009 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 // http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // CGI environment and execution management portions are:
 //
 // ========================================================================
 // Copyright (c) 2006-2009 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 com.google.gerrit.httpd.gitweb;

 import com.google.gerrit.common.data.GerritConfig;
 import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.httpd.GitWebConfig;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.git.LocalDiskRepositoryManager;
 import com.google.gerrit.server.project.NoSuchProjectException;
 import com.google.gerrit.server.project.ProjectControl;
 import com.google.gwtexpui.server.CacheHeaders;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;

 import org.eclipse.jgit.errors.RepositoryNotFoundException;
 import org.eclipse.jgit.lib.Repository;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import java.io.BufferedInputStream;
 import java.io.BufferedReader;
 import java.io.EOFException;
 import java.io.File;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.PrintWriter;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;

 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 /** Invokes {@code gitweb.cgi} for the project given in {@code p}. */
 @SuppressWarnings("serial")
 @Singleton
 class GitWebServlet extends HttpServlet {
   private static final Logger log =
       LoggerFactory.getLogger(GitWebServlet.class);

   private final Set<String> deniedActions;
   private final int bufferSize = 8192;
   private final File gitwebCgi;
   private final URI gitwebUrl;
   private final LocalDiskRepositoryManager repoManager;
   private final ProjectControl.Factory projectControl;
   private final Provider<AnonymousUser> anonymousUserProvider;
   private final EnvList _env;

   @Inject
   GitWebServlet(final LocalDiskRepositoryManager repoManager,
       final ProjectControl.Factory projectControl,
       final Provider<AnonymousUser> anonymousUserProvider,
       final SitePaths site,
       final GerritConfig gerritConfig, final GitWebConfig gitWebConfig)
       throws IOException {
     this.repoManager = repoManager;
     this.projectControl = projectControl;
     this.anonymousUserProvider = anonymousUserProvider;
     this.gitwebCgi = gitWebConfig.getGitwebCGI();
     this.deniedActions = new HashSet<String>();

     final String url = gitWebConfig.getUrl();
     if ((url != null) && (!url.equals("gitweb"))) {
       URI uri = null;
       try {
         uri = new URI(url);
       } catch (URISyntaxException e) {
         log.error("Invalid gitweb.url: " + url);
       }
       gitwebUrl = uri;
     } else {
       gitwebUrl = null;
     }

     deniedActions.add("forks");
     deniedActions.add("opml");
     deniedActions.add("project_list");
     deniedActions.add("project_index");

     _env = new EnvList();
     makeSiteConfig(site, gerritConfig);

     if (!_env.envMap.containsKey("SystemRoot")) {
       String os = System.getProperty("os.name");
       if (os != null && os.toLowerCase().indexOf("windows") != -1) {
         String sysroot = System.getenv("SystemRoot");
         if (sysroot == null || sysroot.isEmpty()) {
           sysroot = "C:\\WINDOWS";
         }
         _env.set("SystemRoot", sysroot);
       }
     }

     if (!_env.envMap.containsKey("PATH")) {
       _env.set("PATH", System.getenv("PATH"));
     }
   }

   private void makeSiteConfig(final SitePaths site,
       final GerritConfig gerritConfig) throws IOException {
     if (!site.tmp_dir.exists()) {
       site.tmp_dir.mkdirs();
     }
     File myconf = File.createTempFile("gitweb_config", ".perl", site.tmp_dir);

     // To make our configuration file only readable or writable by us;
     // this reduces the chances of someone tampering with the file.
     //
     myconf.setWritable(false, false /* all */);
     myconf.setReadable(false, false /* all */);
     myconf.setExecutable(false, false /* all */);

     myconf.setWritable(true, true /* owner only */);
     myconf.setReadable(true, true /* owner only */);

     _env.set("GIT_DIR", ".");
     _env.set("GITWEB_CONFIG", myconf.getAbsolutePath());

     final PrintWriter p = new PrintWriter(new FileWriter(myconf));
     try {
       p.print("# Autogenerated by Gerrit Code Review \n");
       p.print("# DO NOT EDIT\n");
       p.print("\n");

       // We are mounted at the same level in the context as the main
       // UI, so we can include the same header and footer scheme.
       //
       final File hdr = site.site_header;
       if (hdr.isFile()) {
         p.print("$site_header = " + quoteForPerl(hdr) + ";\n");
       }
       final File ftr = site.site_footer;
       if (ftr.isFile()) {
         p.print("$site_footer = " + quoteForPerl(ftr) + ";\n");
       }

       // Top level should return to Gerrit's UI.
       //
       p.print("$home_link = $ENV{'GERRIT_CONTEXT_PATH'};\n");
       p.print("$home_link_str = 'Code Review';\n");

       p.print("$favicon = 'favicon.ico';\n");
       p.print("$logo = 'gitweb-logo.png';\n");
       p.print("$javascript = 'gitweb.js';\n");
       p.print("@stylesheets = ('gitweb-default.css');\n");
       final File css = site.site_css;
       if (css.isFile()) {
         p.print("push @stylesheets, 'gitweb-site.css';\n");
       }

       // Try to make the title match Gerrit's normal window title
       // scheme of host followed by 'Code Review'.
       //
       p.print("$site_name = $home_link_str;\n");
       p.print("$site_name = qq{$1 $site_name} if ");
       p.print("$ENV{'SERVER_NAME'} =~ m,^([^.]+(?:\\.[^.]+)?)(?:\\.|$),;\n");

       // Assume by default that XSS is a problem, and try to prevent it.
       //
       p.print("$prevent_xss = 1;\n");

       // Generate URLs using smart http://
       //
       p.print("{\n");
       p.print("  my $secure = $ENV{'HTTPS'} =~ /^ON$/i;\n");
       p.print("  my $http_url = $secure ? 'https://' : 'http://';\n");
       p.print("  $http_url .= qq{$ENV{'GERRIT_USER_NAME'}@}\n");
       p.print("    unless $ENV{'GERRIT_ANONYMOUS_READ'};\n");
       p.print("  $http_url .= $ENV{'SERVER_NAME'};\n");
       p.print("  $http_url .= qq{:$ENV{'SERVER_PORT'}}\n");
       p.print("    if (( $secure && $ENV{'SERVER_PORT'} != 443)\n");
       p.print("     || (!$secure && $ENV{'SERVER_PORT'} != 80)\n");
       p.print("    );\n");
       p.print("  $http_url .= qq{$ENV{'GERRIT_CONTEXT_PATH'}p};\n");
       p.print("  push @git_base_url_list, $http_url;\n");
       p.print("}\n");

       // Generate URLs using anonymous git://
       //
       if (gerritConfig.getGitDaemonUrl() != null) {
         String url = gerritConfig.getGitDaemonUrl();
         if (url.endsWith("/")) {
           url = url.substring(0, url.length() - 1);
         }
         p.print("if ($ENV{'GERRIT_ANONYMOUS_READ'}) {\n");
         p.print("  push @git_base_url_list, ");
         p.print(quoteForPerl(url));
         p.print(";\n");
         p.print("}\n");
       }

       // Generate URLs using authenticated ssh://
       //
       if (gerritConfig.getSshdAddress() != null) {
         String sshAddr = gerritConfig.getSshdAddress();
         p.print("if ($ENV{'GERRIT_USER_NAME'}) {\n");
         p.print("  push @git_base_url_list, join('', 'ssh://'");
         p.print(", $ENV{'GERRIT_USER_NAME'}");
         p.print(", '@'");
         if (sshAddr.startsWith("*:") || "".equals(sshAddr)) {
           p.print(", $ENV{'SERVER_NAME'}");
         }
         if (sshAddr.startsWith("*")) {
           sshAddr = sshAddr.substring(1);
         }
         p.print(", " + quoteForPerl(sshAddr));
         p.print(");\n");
         p.print("}\n");
       }

       // Link back to Gerrit (when possible, to matching review record).
       // Supported Gitweb's hash values are:
       // - (missing),
       // - HEAD,
       // - refs/heads/<branch>,
       // - refs/changes/*/<change>/*,
       // - <revision>.
       //
       p.print("sub add_review_link {\n");
       p.print("  my $h = shift;\n");
       p.print("  my $q;\n");
       p.print("  if (!$h || $h eq 'HEAD') {\n");
       p.print("    $q = qq{#q,project:$ENV{'GERRIT_PROJECT_NAME'},n,z};\n");
       p.print("  } elsif ($h =~ /^refs\\/heads\\/([-\\w]+)$/) {\n");
       p.print("    $q = qq{#q,project:$ENV{'GERRIT_PROJECT_NAME'}");
       p.print("+branch:$1,n,z};\n"); // wrapped
       p.print("  } elsif ($h =~ /^refs\\/changes\\/\\d{2}\\/(\\d+)\\/\\d+$/) ");
       p.print("{\n"); // wrapped
       p.print("    $q = qq{#/c/$1};\n");
       p.print("  } else {\n");
       p.print("    $q = qq{#/q/$h,n,z};\n");
       p.print("  }\n");
       p.print("  my $r = qq{$ENV{'GERRIT_CONTEXT_PATH'}$q};\n");
       p.print("  push @{$feature{'actions'}{'default'}},\n");
       p.print("      ('review',$r,'commitdiff');\n");
       p.print("}\n");
       p.print("if ($cgi->param('hb')) {\n");
       p.print("  add_review_link($cgi->param('hb'));\n");
       p.print("} elsif ($cgi->param('h')) {\n");
       p.print("  add_review_link($cgi->param('h'));\n");
       p.print("} else {\n");
       p.print("  add_review_link();\n");
       p.print("}\n");

       // If the administrator has created a site-specific gitweb_config,
       // load that before we perform any final overrides.
       //
       final File sitecfg = site.site_gitweb;
       if (sitecfg.isFile()) {
         p.print("$GITWEB_CONFIG = " + quoteForPerl(sitecfg) + ";\n");
         p.print("if (-e $GITWEB_CONFIG) {\n");
         p.print("  do " + quoteForPerl(sitecfg) + ";\n");
         p.print("}\n");
       }

       final File root = repoManager.getBasePath();
       p.print("$projectroot = " + quoteForPerl(root) + ";\n");

       // Permit exporting only the project we were started for.
       // We use the name under $projectroot in case symlinks
       // were involved in the path.
       //
       p.print("$export_auth_hook = sub {\n");
       p.print("    my $dir = shift;\n");
       p.print("    my $name = $ENV{'GERRIT_PROJECT_NAME'};\n");
       p.print("    my $allow = qq{$projectroot/$name.git};\n");
       p.print("    return $dir eq $allow;\n");
       p.print("  };\n");

       // Do not allow the administrator to enable path info, its
       // not a URL format we currently support.
       //
       p.print("$feature{'pathinfo'}{'override'} = 0;\n");
       p.print("$feature{'pathinfo'}{'default'} = [0];\n");

       // We don't do forking, so don't allow it to be enabled.
       //
       p.print("$feature{'forks'}{'override'} = 0;\n");
       p.print("$feature{'forks'}{'default'} = [0];\n");
     } finally {
       p.close();
     }

     myconf.setReadOnly();
   }

   private String quoteForPerl(File value) {
     return quoteForPerl(value.getAbsolutePath());
   }

   private String quoteForPerl(String value) {
     if (value == null || value.isEmpty()) {
       return "''";
     }
     if (!value.contains("'")) {
       return "'" + value + "'";
     }
     if (!value.contains("{") && !value.contains("}")) {
       return "q{" + value + "}";
     }
     throw new IllegalArgumentException("Cannot quote in Perl: " + value);
   }

   @Override
   protected void service(final HttpServletRequest req,
       final HttpServletResponse rsp) throws IOException {
     if (req.getQueryString() == null || req.getQueryString().isEmpty()) {
       // No query string? They want the project list, which we don't
       // currently support. Return to Gerrit's own web UI.
       //
       rsp.sendRedirect(req.getContextPath() + "/");
       return;
     }

     final Map<String, String> params = getParameters(req);
     if (deniedActions.contains(params.get("a"))) {
       rsp.sendError(HttpServletResponse.SC_FORBIDDEN);
       return;
     }

     String name = params.get("p");
     if (name == null) {
       rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
       return;
     }
     if (name.endsWith(".git")) {
       name = name.substring(0, name.length() - 4);
     }

     final Project.NameKey nameKey = new Project.NameKey(name);
     final ProjectControl project;
     try {
       project = projectControl.validateFor(nameKey);
       if (!project.allRefsAreVisible() && !project.isOwner()) {
          // Pretend the project doesn't exist
         throw new NoSuchProjectException(nameKey);
       }
     } catch (NoSuchProjectException e) {
       rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
       return;
     }

     final Repository repo;
     try {
       repo = repoManager.openRepository(nameKey);
     } catch (RepositoryNotFoundException e) {
       getServletContext().log("Cannot open repository", e);
       rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
       return;
     }
     try {
       CacheHeaders.setNotCacheable(rsp);
       exec(req, rsp, project, repo);
     } finally {
       repo.close();
     }
   }

   private static Map<String, String> getParameters(HttpServletRequest req) {
     final Map<String, String> params = new HashMap<String, String>();
     for (final String pair : req.getQueryString().split("[&;]")) {
       final int eq = pair.indexOf('=');
       if (0 < eq) {
         String name = pair.substring(0, eq);
         String value = pair.substring(eq + 1);

         name = Url.decode(name);
         value = Url.decode(value);
         params.put(name, value);
       }
     }
     return params;
   }

   private void exec(final HttpServletRequest req,
       final HttpServletResponse rsp, final ProjectControl project,
       final Repository repo) throws IOException {
     final Process proc =
         Runtime.getRuntime().exec(new String[] {gitwebCgi.getAbsolutePath()},
             makeEnv(req, project),
             gitwebCgi.getAbsoluteFile().getParentFile());

     copyStderrToLog(proc.getErrorStream());
     if (0 < req.getContentLength()) {
       copyContentToCGI(req, proc.getOutputStream());
     } else {
       proc.getOutputStream().close();
     }

     try {
       final InputStream in;

       in = new BufferedInputStream(proc.getInputStream(), bufferSize);
       try {
         readCgiHeaders(rsp, in);

         final OutputStream out = rsp.getOutputStream();
         try {
           final byte[] buf = new byte[bufferSize];
           int n;
           while ((n = in.read(buf)) > 0) {
             out.write(buf, 0, n);
           }
         } finally {
           out.close();
         }
       } finally {
         in.close();
       }
     } catch (IOException e) {
       // The browser has probably closed its input stream. We don't
       // want to continue executing this request.
       //
       proc.destroy();
       return;
     }

     try {
       proc.waitFor();

       final int status = proc.exitValue();
       if (0 != status) {
         log.error("Non-zero exit status (" + status + ") from " + gitwebCgi);
         if (!rsp.isCommitted()) {
           rsp.sendError(500);
         }
       }
     } catch (InterruptedException ie) {
       log.debug("CGI: interrupted waiting for CGI to terminate");
     }
   }

   private String[] makeEnv(final HttpServletRequest req,
       final ProjectControl project) {
     final EnvList env = new EnvList(_env);
     final int contentLength = Math.max(0, req.getContentLength());

     // These ones are from "The WWW Common Gateway Interface Version 1.1"
     //
     env.set("AUTH_TYPE", req.getAuthType());
     env.set("CONTENT_LENGTH", Integer.toString(contentLength));
     env.set("CONTENT_TYPE", req.getContentType());
     env.set("GATEWAY_INTERFACE", "CGI/1.1");
     env.set("PATH_INFO", req.getPathInfo());
     env.set("PATH_TRANSLATED", null);
     env.set("QUERY_STRING", req.getQueryString());
     env.set("REMOTE_ADDR", req.getRemoteAddr());
     env.set("REMOTE_HOST", req.getRemoteHost());
     env.set("HTTPS", req.isSecure() ? "ON" : "OFF");

     // The identity information reported about the connection by a
     // RFC 1413 [11] request to the remote agent, if
     // available. Servers MAY choose not to support this feature, or
     // not to request the data for efficiency reasons.
     // "REMOTE_IDENT" => "NYI"
     //
     env.set("REQUEST_METHOD", req.getMethod());
     env.set("SCRIPT_NAME", req.getContextPath() + req.getServletPath());
     env.set("SCRIPT_FILENAME", gitwebCgi.getAbsolutePath());
     env.set("SERVER_NAME", req.getServerName());
     env.set("SERVER_PORT", Integer.toString(req.getServerPort()));
     env.set("SERVER_PROTOCOL", req.getProtocol());
     env.set("SERVER_SOFTWARE", getServletContext().getServerInfo());

     final Enumeration<String> hdrs = enumerateHeaderNames(req);
     while (hdrs.hasMoreElements()) {
       final String name = hdrs.nextElement();
       final String value = req.getHeader(name);
       env.set("HTTP_" + name.toUpperCase().replace('-', '_'), value);
     }

     env.set("GERRIT_CONTEXT_PATH", req.getContextPath() + "/");
     env.set("GERRIT_PROJECT_NAME", project.getProject().getName());

     if (project.forUser(anonymousUserProvider.get()).isVisible()) {
       env.set("GERRIT_ANONYMOUS_READ", "1");
     }

     String remoteUser = null;
     if (project.getCurrentUser() instanceof IdentifiedUser) {
       final IdentifiedUser u = (IdentifiedUser) project.getCurrentUser();
       final String user = u.getUserName();
       env.set("GERRIT_USER_NAME", user);
       if (user != null && !user.isEmpty()) {
         remoteUser = user;
       } else {
         remoteUser = "account-" + u.getAccountId();
       }
     }
     env.set("REMOTE_USER", remoteUser);

     // Override CGI settings using alternative URI provided by gitweb.url.
     // This is required to trick Gitweb into thinking that it's served under
     // different URL. Setting just $my_uri on the perl's side isn't enough,
     // because few actions (atom, blobdiff_plain, commitdiff_plain) rely on
     // URL returned by $cgi->self_url().
     //
     if (gitwebUrl != null) {
       int schemePort = -1;

       if (gitwebUrl.getScheme() != null) {
         if (gitwebUrl.getScheme().equals("http")) {
           env.set("HTTPS", "OFF");
           schemePort = 80;
         } else {
           env.set("HTTPS", "ON");
           schemePort = 443;
         }
       }

       if (gitwebUrl.getHost() != null) {
         env.set("SERVER_NAME", gitwebUrl.getHost());
         env.set("HTTP_HOST", gitwebUrl.getHost());
       }

       if (gitwebUrl.getPort() != -1) {
         env.set("SERVER_PORT", Integer.toString(gitwebUrl.getPort()));
       } else if (schemePort != -1) {
         env.set("SERVER_PORT", Integer.toString(schemePort));
       }

       if (gitwebUrl.getPath() != null) {
         env.set("SCRIPT_NAME", gitwebUrl.getPath().isEmpty()
                                ? "/" : gitwebUrl.getPath());
       }
     }

     return env.getEnvArray();
   }

   private void copyContentToCGI(final HttpServletRequest req,
       final OutputStream dst) throws IOException {
     final int contentLength = req.getContentLength();
     final InputStream src = req.getInputStream();
     new Thread(new Runnable() {
       public void run() {
         try {
           try {
             final byte[] buf = new byte[bufferSize];
             int remaining = contentLength;
             while (0 < remaining) {
               final int max = Math.max(buf.length, remaining);
               final int n = src.read(buf, 0, max);
               if (n < 0) {
                 throw new EOFException("Expected " + remaining + " more bytes");
               }
               dst.write(buf, 0, n);
               remaining -= n;
             }
           } finally {
             dst.close();
           }
         } catch (IOException e) {
           log.debug("Unexpected error copying input to CGI", e);
         }
       }
     }, "GitWeb-InputFeeder").start();
   }

   private void copyStderrToLog(final InputStream in) {
     new Thread(new Runnable() {
       public void run() {
         try {
           final BufferedReader br =
               new BufferedReader(new InputStreamReader(in, "ISO-8859-1"));
           try {
             String line;
             while ((line = br.readLine()) != null) {
               log.error("CGI: " + line);
             }
           } finally {
             br.close();
           }
         } catch (IOException e) {
           log.debug("Unexpected error copying stderr from CGI", e);
         }
       }
     }, "GitWeb-ErrorLogger").start();
   }

   @SuppressWarnings("unchecked")
   private static Enumeration<String> enumerateHeaderNames(HttpServletRequest req) {
     return req.getHeaderNames();
   }

   private void readCgiHeaders(HttpServletResponse res, final InputStream in)
       throws IOException {
     String line;
     while (!(line = readLine(in)).isEmpty()) {
       if (line.startsWith("HTTP")) {
         // CGI believes it is a non-parsed-header CGI. We refuse
         // to support that here so abort.
         //
         throw new IOException("NPH CGI not supported: " + line);
       }

       final int sep = line.indexOf(':');
       if (sep < 0) {
         throw new IOException("CGI returned invalid header: " + line);
       }

       final String key = line.substring(0, sep).trim();
       final String value = line.substring(sep + 1).trim();
       if ("Location".equalsIgnoreCase(key)) {
         res.sendRedirect(value);

       } else if ("Status".equalsIgnoreCase(key)) {
         final String[] token = value.split(" ");
         final int status = Integer.parseInt(token[0]);
         res.setStatus(status);

       } else {
         res.addHeader(key, value);
       }
     }
   }

   private String readLine(final InputStream in) throws IOException {
     final StringBuilder buf = new StringBuilder();
     int b;
     while ((b = in.read()) != -1 && b != '\n') {
       buf.append((char) b);
     }
     return buf.toString().trim();
   }

   /** private utility class that manages the Environment passed to exec. */
   private static class EnvList {
     private Map<String, String> envMap;

     EnvList() {
       envMap = new HashMap<String, String>();
     }

     EnvList(final EnvList l) {
       envMap = new HashMap<String, String>(l.envMap);
     }

     /** Set a name/value pair, null values will be treated as an empty String */
     public void set(final String name, String value) {
       if (value == null) {
         value = "";
       }
       envMap.put(name, name + "=" + value);
     }

     /** Get representation suitable for passing to exec. */
     public String[] getEnvArray() {
       return envMap.values().toArray(new String[envMap.size()]);
     }

     @Override
     public String toString() {
       return envMap.toString();
     }
   }
 }
	// Copyright (C) 2009 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// CGI environment and execution management portions are:
	//
	// ========================================================================
	// Copyright (c) 2006-2009 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 com.google.gerrit.httpd.gitweb;

	import com.google.gerrit.common.data.GerritConfig;
	import com.google.gerrit.extensions.restapi.Url;
	import com.google.gerrit.httpd.GitWebConfig;
	import com.google.gerrit.reviewdb.client.Project;
	import com.google.gerrit.server.AnonymousUser;
	import com.google.gerrit.server.IdentifiedUser;
	import com.google.gerrit.server.config.SitePaths;
	import com.google.gerrit.server.git.LocalDiskRepositoryManager;
	import com.google.gerrit.server.project.NoSuchProjectException;
	import com.google.gerrit.server.project.ProjectControl;
	import com.google.gwtexpui.server.CacheHeaders;
	import com.google.inject.Inject;
	import com.google.inject.Provider;
	import com.google.inject.Singleton;

	import org.eclipse.jgit.errors.RepositoryNotFoundException;
	import org.eclipse.jgit.lib.Repository;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import java.io.BufferedInputStream;
	import java.io.BufferedReader;
	import java.io.EOFException;
	import java.io.File;
	import java.io.FileWriter;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.io.OutputStream;
	import java.io.PrintWriter;
	import java.net.URI;
	import java.net.URISyntaxException;
	import java.util.Enumeration;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Map;
	import java.util.Set;

	import javax.servlet.http.HttpServlet;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	/** Invokes {@code gitweb.cgi} for the project given in {@code p}. */
	@SuppressWarnings("serial")
	@Singleton
	class GitWebServlet extends HttpServlet {
	private static final Logger log =
	LoggerFactory.getLogger(GitWebServlet.class);

	private final Set<String> deniedActions;
	private final int bufferSize = 8192;
	private final File gitwebCgi;
	private final URI gitwebUrl;
	private final LocalDiskRepositoryManager repoManager;
	private final ProjectControl.Factory projectControl;
	private final Provider<AnonymousUser> anonymousUserProvider;
	private final EnvList _env;

	@Inject
	GitWebServlet(final LocalDiskRepositoryManager repoManager,
	final ProjectControl.Factory projectControl,
	final Provider<AnonymousUser> anonymousUserProvider,
	final SitePaths site,
	final GerritConfig gerritConfig, final GitWebConfig gitWebConfig)
	throws IOException {
	this.repoManager = repoManager;
	this.projectControl = projectControl;
	this.anonymousUserProvider = anonymousUserProvider;
	this.gitwebCgi = gitWebConfig.getGitwebCGI();
	this.deniedActions = new HashSet<String>();

	final String url = gitWebConfig.getUrl();
	if ((url != null) && (!url.equals("gitweb"))) {
	URI uri = null;
	try {
	uri = new URI(url);
	} catch (URISyntaxException e) {
	log.error("Invalid gitweb.url: " + url);
	}
	gitwebUrl = uri;
	} else {
	gitwebUrl = null;
	}

	deniedActions.add("forks");
	deniedActions.add("opml");
	deniedActions.add("project_list");
	deniedActions.add("project_index");

	_env = new EnvList();
	makeSiteConfig(site, gerritConfig);

	if (!_env.envMap.containsKey("SystemRoot")) {
	String os = System.getProperty("os.name");
	if (os != null && os.toLowerCase().indexOf("windows") != -1) {
	String sysroot = System.getenv("SystemRoot");
	if (sysroot == null \|\| sysroot.isEmpty()) {
	sysroot = "C:\\WINDOWS";
	}
	_env.set("SystemRoot", sysroot);
	}
	}

	if (!_env.envMap.containsKey("PATH")) {
	_env.set("PATH", System.getenv("PATH"));
	}
	}

	private void makeSiteConfig(final SitePaths site,
	final GerritConfig gerritConfig) throws IOException {
	if (!site.tmp_dir.exists()) {
	site.tmp_dir.mkdirs();
	}
	File myconf = File.createTempFile("gitweb_config", ".perl", site.tmp_dir);

	// To make our configuration file only readable or writable by us;
	// this reduces the chances of someone tampering with the file.
	//
	myconf.setWritable(false, false /* all */);
	myconf.setReadable(false, false /* all */);
	myconf.setExecutable(false, false /* all */);

	myconf.setWritable(true, true /* owner only */);
	myconf.setReadable(true, true /* owner only */);

	_env.set("GIT_DIR", ".");
	_env.set("GITWEB_CONFIG", myconf.getAbsolutePath());

	final PrintWriter p = new PrintWriter(new FileWriter(myconf));
	try {
	p.print("# Autogenerated by Gerrit Code Review \n");
	p.print("# DO NOT EDIT\n");
	p.print("\n");

	// We are mounted at the same level in the context as the main
	// UI, so we can include the same header and footer scheme.
	//
	final File hdr = site.site_header;
	if (hdr.isFile()) {
	p.print("$site_header = " + quoteForPerl(hdr) + ";\n");
	}
	final File ftr = site.site_footer;
	if (ftr.isFile()) {
	p.print("$site_footer = " + quoteForPerl(ftr) + ";\n");
	}

	// Top level should return to Gerrit's UI.
	//
	p.print("$home_link = $ENV{'GERRIT_CONTEXT_PATH'};\n");
	p.print("$home_link_str = 'Code Review';\n");

	p.print("$favicon = 'favicon.ico';\n");
	p.print("$logo = 'gitweb-logo.png';\n");
	p.print("$javascript = 'gitweb.js';\n");
	p.print("@stylesheets = ('gitweb-default.css');\n");
	final File css = site.site_css;
	if (css.isFile()) {
	p.print("push @stylesheets, 'gitweb-site.css';\n");
	}

	// Try to make the title match Gerrit's normal window title
	// scheme of host followed by 'Code Review'.
	//
	p.print("$site_name = $home_link_str;\n");
	p.print("$site_name = qq{$1 $site_name} if ");
	p.print("$ENV{'SERVER_NAME'} =~ m,^([^.]+(?:\\.[^.]+)?)(?:\\.\|$),;\n");

	// Assume by default that XSS is a problem, and try to prevent it.
	//
	p.print("$prevent_xss = 1;\n");

	// Generate URLs using smart http://
	//
	p.print("{\n");
	p.print(" my $secure = $ENV{'HTTPS'} =~ /^ON$/i;\n");
	p.print(" my $http_url = $secure ? 'https://' : 'http://';\n");
	p.print(" $http_url .= qq{$ENV{'GERRIT_USER_NAME'}@}\n");
	p.print(" unless $ENV{'GERRIT_ANONYMOUS_READ'};\n");
	p.print(" $http_url .= $ENV{'SERVER_NAME'};\n");
	p.print(" $http_url .= qq{:$ENV{'SERVER_PORT'}}\n");
	p.print(" if (( $secure && $ENV{'SERVER_PORT'} != 443)\n");
	p.print(" \|\| (!$secure && $ENV{'SERVER_PORT'} != 80)\n");
	p.print(" );\n");
	p.print(" $http_url .= qq{$ENV{'GERRIT_CONTEXT_PATH'}p};\n");
	p.print(" push @git_base_url_list, $http_url;\n");
	p.print("}\n");

	// Generate URLs using anonymous git://
	//
	if (gerritConfig.getGitDaemonUrl() != null) {
	String url = gerritConfig.getGitDaemonUrl();
	if (url.endsWith("/")) {
	url = url.substring(0, url.length() - 1);
	}
	p.print("if ($ENV{'GERRIT_ANONYMOUS_READ'}) {\n");
	p.print(" push @git_base_url_list, ");
	p.print(quoteForPerl(url));
	p.print(";\n");
	p.print("}\n");
	}

	// Generate URLs using authenticated ssh://
	//
	if (gerritConfig.getSshdAddress() != null) {
	String sshAddr = gerritConfig.getSshdAddress();
	p.print("if ($ENV{'GERRIT_USER_NAME'}) {\n");
	p.print(" push @git_base_url_list, join('', 'ssh://'");
	p.print(", $ENV{'GERRIT_USER_NAME'}");
	p.print(", '@'");
	if (sshAddr.startsWith("*:") \|\| "".equals(sshAddr)) {
	p.print(", $ENV{'SERVER_NAME'}");
	}
	if (sshAddr.startsWith("*")) {
	sshAddr = sshAddr.substring(1);
	}
	p.print(", " + quoteForPerl(sshAddr));
	p.print(");\n");
	p.print("}\n");
	}

	// Link back to Gerrit (when possible, to matching review record).
	// Supported Gitweb's hash values are:
	// - (missing),
	// - HEAD,
	// - refs/heads/<branch>,
	// - refs/changes//<change>/,
	// - <revision>.
	//
	p.print("sub add_review_link {\n");
	p.print(" my $h = shift;\n");
	p.print(" my $q;\n");
	p.print(" if (!$h \|\| $h eq 'HEAD') {\n");
	p.print(" $q = qq{#q,project:$ENV{'GERRIT_PROJECT_NAME'},n,z};\n");
	p.print(" } elsif ($h =~ /^refs\\/heads\\/([-\\w]+)$/) {\n");
	p.print(" $q = qq{#q,project:$ENV{'GERRIT_PROJECT_NAME'}");
	p.print("+branch:$1,n,z};\n"); // wrapped
	p.print(" } elsif ($h =~ /^refs\\/changes\\/\\d{2}\\/(\\d+)\\/\\d+$/) ");
	p.print("{\n"); // wrapped
	p.print(" $q = qq{#/c/$1};\n");
	p.print(" } else {\n");
	p.print(" $q = qq{#/q/$h,n,z};\n");
	p.print(" }\n");
	p.print(" my $r = qq{$ENV{'GERRIT_CONTEXT_PATH'}$q};\n");
	p.print(" push @{$feature{'actions'}{'default'}},\n");
	p.print(" ('review',$r,'commitdiff');\n");
	p.print("}\n");
	p.print("if ($cgi->param('hb')) {\n");
	p.print(" add_review_link($cgi->param('hb'));\n");
	p.print("} elsif ($cgi->param('h')) {\n");
	p.print(" add_review_link($cgi->param('h'));\n");
	p.print("} else {\n");
	p.print(" add_review_link();\n");
	p.print("}\n");

	// If the administrator has created a site-specific gitweb_config,
	// load that before we perform any final overrides.
	//
	final File sitecfg = site.site_gitweb;
	if (sitecfg.isFile()) {
	p.print("$GITWEB_CONFIG = " + quoteForPerl(sitecfg) + ";\n");
	p.print("if (-e $GITWEB_CONFIG) {\n");
	p.print(" do " + quoteForPerl(sitecfg) + ";\n");
	p.print("}\n");
	}

	final File root = repoManager.getBasePath();
	p.print("$projectroot = " + quoteForPerl(root) + ";\n");

	// Permit exporting only the project we were started for.
	// We use the name under $projectroot in case symlinks
	// were involved in the path.
	//
	p.print("$export_auth_hook = sub {\n");
	p.print(" my $dir = shift;\n");
	p.print(" my $name = $ENV{'GERRIT_PROJECT_NAME'};\n");
	p.print(" my $allow = qq{$projectroot/$name.git};\n");
	p.print(" return $dir eq $allow;\n");
	p.print(" };\n");

	// Do not allow the administrator to enable path info, its
	// not a URL format we currently support.
	//
	p.print("$feature{'pathinfo'}{'override'} = 0;\n");
	p.print("$feature{'pathinfo'}{'default'} = [0];\n");

	// We don't do forking, so don't allow it to be enabled.
	//
	p.print("$feature{'forks'}{'override'} = 0;\n");
	p.print("$feature{'forks'}{'default'} = [0];\n");
	} finally {
	p.close();
	}

	myconf.setReadOnly();
	}

	private String quoteForPerl(File value) {
	return quoteForPerl(value.getAbsolutePath());
	}

	private String quoteForPerl(String value) {
	if (value == null \|\| value.isEmpty()) {
	return "''";
	}
	if (!value.contains("'")) {
	return "'" + value + "'";
	}
	if (!value.contains("{") && !value.contains("}")) {
	return "q{" + value + "}";
	}
	throw new IllegalArgumentException("Cannot quote in Perl: " + value);
	}

	@Override
	protected void service(final HttpServletRequest req,
	final HttpServletResponse rsp) throws IOException {
	if (req.getQueryString() == null \|\| req.getQueryString().isEmpty()) {
	// No query string? They want the project list, which we don't
	// currently support. Return to Gerrit's own web UI.
	//
	rsp.sendRedirect(req.getContextPath() + "/");
	return;
	}

	final Map<String, String> params = getParameters(req);
	if (deniedActions.contains(params.get("a"))) {
	rsp.sendError(HttpServletResponse.SC_FORBIDDEN);
	return;
	}

	String name = params.get("p");
	if (name == null) {
	rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
	return;
	}
	if (name.endsWith(".git")) {
	name = name.substring(0, name.length() - 4);
	}

	final Project.NameKey nameKey = new Project.NameKey(name);
	final ProjectControl project;
	try {
	project = projectControl.validateFor(nameKey);
	if (!project.allRefsAreVisible() && !project.isOwner()) {
	// Pretend the project doesn't exist
	throw new NoSuchProjectException(nameKey);
	}
	} catch (NoSuchProjectException e) {
	rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
	return;
	}

	final Repository repo;
	try {
	repo = repoManager.openRepository(nameKey);
	} catch (RepositoryNotFoundException e) {
	getServletContext().log("Cannot open repository", e);
	rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
	return;
	}
	try {
	CacheHeaders.setNotCacheable(rsp);
	exec(req, rsp, project, repo);
	} finally {
	repo.close();
	}
	}

	private static Map<String, String> getParameters(HttpServletRequest req) {
	final Map<String, String> params = new HashMap<String, String>();
	for (final String pair : req.getQueryString().split("[&;]")) {
	final int eq = pair.indexOf('=');
	if (0 < eq) {
	String name = pair.substring(0, eq);
	String value = pair.substring(eq + 1);

	name = Url.decode(name);
	value = Url.decode(value);
	params.put(name, value);
	}
	}
	return params;
	}

	private void exec(final HttpServletRequest req,
	final HttpServletResponse rsp, final ProjectControl project,
	final Repository repo) throws IOException {
	final Process proc =
	Runtime.getRuntime().exec(new String[] {gitwebCgi.getAbsolutePath()},
	makeEnv(req, project),
	gitwebCgi.getAbsoluteFile().getParentFile());

	copyStderrToLog(proc.getErrorStream());
	if (0 < req.getContentLength()) {
	copyContentToCGI(req, proc.getOutputStream());
	} else {
	proc.getOutputStream().close();
	}

	try {
	final InputStream in;

	in = new BufferedInputStream(proc.getInputStream(), bufferSize);
	try {
	readCgiHeaders(rsp, in);

	final OutputStream out = rsp.getOutputStream();
	try {
	final byte[] buf = new byte[bufferSize];
	int n;
	while ((n = in.read(buf)) > 0) {
	out.write(buf, 0, n);
	}
	} finally {
	out.close();
	}
	} finally {
	in.close();
	}
	} catch (IOException e) {
	// The browser has probably closed its input stream. We don't
	// want to continue executing this request.
	//
	proc.destroy();
	return;
	}

	try {
	proc.waitFor();

	final int status = proc.exitValue();
	if (0 != status) {
	log.error("Non-zero exit status (" + status + ") from " + gitwebCgi);
	if (!rsp.isCommitted()) {
	rsp.sendError(500);
	}
	}
	} catch (InterruptedException ie) {
	log.debug("CGI: interrupted waiting for CGI to terminate");
	}
	}

	private String[] makeEnv(final HttpServletRequest req,
	final ProjectControl project) {
	final EnvList env = new EnvList(_env);
	final int contentLength = Math.max(0, req.getContentLength());

	// These ones are from "The WWW Common Gateway Interface Version 1.1"
	//
	env.set("AUTH_TYPE", req.getAuthType());
	env.set("CONTENT_LENGTH", Integer.toString(contentLength));
	env.set("CONTENT_TYPE", req.getContentType());
	env.set("GATEWAY_INTERFACE", "CGI/1.1");
	env.set("PATH_INFO", req.getPathInfo());
	env.set("PATH_TRANSLATED", null);
	env.set("QUERY_STRING", req.getQueryString());
	env.set("REMOTE_ADDR", req.getRemoteAddr());
	env.set("REMOTE_HOST", req.getRemoteHost());
	env.set("HTTPS", req.isSecure() ? "ON" : "OFF");

	// The identity information reported about the connection by a
	// RFC 1413 [11] request to the remote agent, if
	// available. Servers MAY choose not to support this feature, or
	// not to request the data for efficiency reasons.
	// "REMOTE_IDENT" => "NYI"
	//
	env.set("REQUEST_METHOD", req.getMethod());
	env.set("SCRIPT_NAME", req.getContextPath() + req.getServletPath());
	env.set("SCRIPT_FILENAME", gitwebCgi.getAbsolutePath());
	env.set("SERVER_NAME", req.getServerName());
	env.set("SERVER_PORT", Integer.toString(req.getServerPort()));
	env.set("SERVER_PROTOCOL", req.getProtocol());
	env.set("SERVER_SOFTWARE", getServletContext().getServerInfo());

	final Enumeration<String> hdrs = enumerateHeaderNames(req);
	while (hdrs.hasMoreElements()) {
	final String name = hdrs.nextElement();
	final String value = req.getHeader(name);
	env.set("HTTP_" + name.toUpperCase().replace('-', '_'), value);
	}

	env.set("GERRIT_CONTEXT_PATH", req.getContextPath() + "/");
	env.set("GERRIT_PROJECT_NAME", project.getProject().getName());

	if (project.forUser(anonymousUserProvider.get()).isVisible()) {
	env.set("GERRIT_ANONYMOUS_READ", "1");
	}

	String remoteUser = null;
	if (project.getCurrentUser() instanceof IdentifiedUser) {
	final IdentifiedUser u = (IdentifiedUser) project.getCurrentUser();
	final String user = u.getUserName();
	env.set("GERRIT_USER_NAME", user);
	if (user != null && !user.isEmpty()) {
	remoteUser = user;
	} else {
	remoteUser = "account-" + u.getAccountId();
	}
	}
	env.set("REMOTE_USER", remoteUser);

	// Override CGI settings using alternative URI provided by gitweb.url.
	// This is required to trick Gitweb into thinking that it's served under
	// different URL. Setting just $my_uri on the perl's side isn't enough,
	// because few actions (atom, blobdiff_plain, commitdiff_plain) rely on
	// URL returned by $cgi->self_url().
	//
	if (gitwebUrl != null) {
	int schemePort = -1;

	if (gitwebUrl.getScheme() != null) {
	if (gitwebUrl.getScheme().equals("http")) {
	env.set("HTTPS", "OFF");
	schemePort = 80;
	} else {
	env.set("HTTPS", "ON");
	schemePort = 443;
	}
	}

	if (gitwebUrl.getHost() != null) {
	env.set("SERVER_NAME", gitwebUrl.getHost());
	env.set("HTTP_HOST", gitwebUrl.getHost());
	}

	if (gitwebUrl.getPort() != -1) {
	env.set("SERVER_PORT", Integer.toString(gitwebUrl.getPort()));
	} else if (schemePort != -1) {
	env.set("SERVER_PORT", Integer.toString(schemePort));
	}

	if (gitwebUrl.getPath() != null) {
	env.set("SCRIPT_NAME", gitwebUrl.getPath().isEmpty()
	? "/" : gitwebUrl.getPath());
	}
	}

	return env.getEnvArray();
	}

	private void copyContentToCGI(final HttpServletRequest req,
	final OutputStream dst) throws IOException {
	final int contentLength = req.getContentLength();
	final InputStream src = req.getInputStream();
	new Thread(new Runnable() {
	public void run() {
	try {
	try {
	final byte[] buf = new byte[bufferSize];
	int remaining = contentLength;
	while (0 < remaining) {
	final int max = Math.max(buf.length, remaining);
	final int n = src.read(buf, 0, max);
	if (n < 0) {
	throw new EOFException("Expected " + remaining + " more bytes");
	}
	dst.write(buf, 0, n);
	remaining -= n;
	}
	} finally {
	dst.close();
	}
	} catch (IOException e) {
	log.debug("Unexpected error copying input to CGI", e);
	}
	}
	}, "GitWeb-InputFeeder").start();
	}

	private void copyStderrToLog(final InputStream in) {
	new Thread(new Runnable() {
	public void run() {
	try {
	final BufferedReader br =
	new BufferedReader(new InputStreamReader(in, "ISO-8859-1"));
	try {
	String line;
	while ((line = br.readLine()) != null) {
	log.error("CGI: " + line);
	}
	} finally {
	br.close();
	}
	} catch (IOException e) {
	log.debug("Unexpected error copying stderr from CGI", e);
	}
	}
	}, "GitWeb-ErrorLogger").start();
	}

	@SuppressWarnings("unchecked")
	private static Enumeration<String> enumerateHeaderNames(HttpServletRequest req) {
	return req.getHeaderNames();
	}

	private void readCgiHeaders(HttpServletResponse res, final InputStream in)
	throws IOException {
	String line;
	while (!(line = readLine(in)).isEmpty()) {
	if (line.startsWith("HTTP")) {
	// CGI believes it is a non-parsed-header CGI. We refuse
	// to support that here so abort.
	//
	throw new IOException("NPH CGI not supported: " + line);
	}

	final int sep = line.indexOf(':');
	if (sep < 0) {
	throw new IOException("CGI returned invalid header: " + line);
	}

	final String key = line.substring(0, sep).trim();
	final String value = line.substring(sep + 1).trim();
	if ("Location".equalsIgnoreCase(key)) {
	res.sendRedirect(value);

	} else if ("Status".equalsIgnoreCase(key)) {
	final String[] token = value.split(" ");
	final int status = Integer.parseInt(token[0]);
	res.setStatus(status);

	} else {
	res.addHeader(key, value);
	}
	}
	}

	private String readLine(final InputStream in) throws IOException {
	final StringBuilder buf = new StringBuilder();
	int b;
	while ((b = in.read()) != -1 && b != '\n') {
	buf.append((char) b);
	}
	return buf.toString().trim();
	}

	/** private utility class that manages the Environment passed to exec. */
	private static class EnvList {
	private Map<String, String> envMap;

	EnvList() {
	envMap = new HashMap<String, String>();
	}

	EnvList(final EnvList l) {
	envMap = new HashMap<String, String>(l.envMap);
	}

	/** Set a name/value pair, null values will be treated as an empty String */
	public void set(final String name, String value) {
	if (value == null) {
	value = "";
	}
	envMap.put(name, name + "=" + value);
	}

	/** Get representation suitable for passing to exec. */
	public String[] getEnvArray() {
	return envMap.values().toArray(new String[envMap.size()]);
	}

	@Override
	public String toString() {
	return envMap.toString();
	}
	}
	}