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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
package org.apache.catalina.servlets;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.List;
import java.util.Locale;
import java.util.Map.Entry;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.regex.Pattern;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.catalina.util.IOTools;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.res.StringManager;


/**
 *  CGI-invoking servlet for web applications, used to execute scripts which
 *  comply to the Common Gateway Interface (CGI) specification and are named
 *  in the path-info used to invoke this servlet.
 *
 * 

* Note: This code compiles and even works for simple CGI cases. * Exhaustive testing has not been done. Please consider it beta * quality. Feedback is appreciated to the author (see below). *

*

* * Example:
* If an instance of this servlet was mapped (using * <web-app>/WEB-INF/web.xml) to: *

*

* * <web-app>/cgi-bin/* * *

*

* then the following request: *

*

* * http://localhost:8080/<web-app>/cgi-bin/dir1/script/pathinfo1 * *

*

* would result in the execution of the script *

*

* * <web-app-root>/WEB-INF/cgi/dir1/script * *

*

* with the script's PATH_INFO set to /pathinfo1. *

*

* Recommendation: House all your CGI scripts under * <webapp>/WEB-INF/cgi. This will ensure that you do not * accidentally expose your cgi scripts' code to the outside world and that * your cgis will be cleanly ensconced underneath the WEB-INF (i.e., * non-content) area. *

*

* The default CGI location is mentioned above. You have the flexibility to * put CGIs wherever you want, however: *

*

* The CGI search path will start at * webAppRootDir + File.separator + cgiPathPrefix * (or webAppRootDir alone if cgiPathPrefix is * null). *

*

* cgiPathPrefix is defined by setting * this servlet's cgiPathPrefix init parameter *

* *

* * CGI Specification:
derived from * http://cgi-spec.golux.com. * A work-in-progress & expired Internet Draft. Note no actual RFC describing * the CGI specification exists. Where the behavior of this servlet differs * from the specification cited above, it is either documented here, a bug, * or an instance where the specification cited differs from Best * Community Practice (BCP). * Such instances should be well-documented here. Please email the * Tomcat group * with amendments. * *

*

* * Canonical metavariables:
* The CGI specification defines the following canonical metavariables: *
* [excerpt from CGI specification] *

 *  AUTH_TYPE
 *  CONTENT_LENGTH
 *  CONTENT_TYPE
 *  GATEWAY_INTERFACE
 *  PATH_INFO
 *  PATH_TRANSLATED
 *  QUERY_STRING
 *  REMOTE_ADDR
 *  REMOTE_HOST
 *  REMOTE_IDENT
 *  REMOTE_USER
 *  REQUEST_METHOD
 *  SCRIPT_NAME
 *  SERVER_NAME
 *  SERVER_PORT
 *  SERVER_PROTOCOL
 *  SERVER_SOFTWARE
 * 
*

* Metavariables with names beginning with the protocol name (e.g., * "HTTP_ACCEPT") are also canonical in their description of request header * fields. The number and meaning of these fields may change independently * of this specification. (See also section 6.1.5 [of the CGI specification].) *

* [end excerpt] * *

Implementation notes

*

* * standard input handling: If your script accepts standard input, * then the client must start sending input within a certain timeout period, * otherwise the servlet will assume no input is coming and carry on running * the script. The script's the standard input will be closed and handling of * any further input from the client is undefined. Most likely it will be * ignored. If this behavior becomes undesirable, then this servlet needs * to be enhanced to handle threading of the spawned process' stdin, stdout, * and stderr (which should not be too hard). *
* If you find your cgi scripts are timing out receiving input, you can set * the init parameter stderrTimeout of your webapps' cgi-handling * servlet. *

*

* * Metavariable Values: According to the CGI specification, * implementations may choose to represent both null or missing values in an * implementation-specific manner, but must define that manner. This * implementation chooses to always define all required metavariables, but * set the value to "" for all metavariables whose value is either null or * undefined. PATH_TRANSLATED is the sole exception to this rule, as per the * CGI Specification. * *

*

* * NPH -- Non-parsed-header implementation: This implementation does * not support the CGI NPH concept, whereby server ensures that the data * supplied to the script are precisely as supplied by the client and * unaltered by the server. *

*

* The function of a servlet container (including Tomcat) is specifically * designed to parse and possible alter CGI-specific variables, and as * such makes NPH functionality difficult to support. *

*

* The CGI specification states that compliant servers MAY support NPH output. * It does not state servers MUST support NPH output to be unconditionally * compliant. Thus, this implementation maintains unconditional compliance * with the specification though NPH support is not present. *

*

* * The CGI specification is located at * http://cgi-spec.golux.com. * *

*

TODO:

*
    *
  • Support for setting headers (for example, Location headers don't work) *
  • Support for collapsing multiple header lines (per RFC 2616) *
  • Ensure handling of POST method does not interfere with 2.3 Filters *
  • Refactor some debug code out of core *
  • Ensure header handling preserves encoding *
  • Possibly rewrite CGIRunner.run()? *
  • Possibly refactor CGIRunner and CGIEnvironment as non-inner classes? *
  • Document handling of cgi stdin when there is no stdin *
  • Revisit IOException handling in CGIRunner.run() *
  • Better documentation *
  • Confirm use of ServletInputStream.available() in CGIRunner.run() is * not needed *
  • [add more to this TODO list] *
* * @author Martin T Dengler [[email protected]] * @author Amy Roh */ public final class CGIServlet extends HttpServlet { private static final Log log = LogFactory.getLog(CGIServlet.class); private static final StringManager sm = StringManager.getManager(CGIServlet.class); private static final String LINE_SEP = System.getProperty("line.separator"); /* some vars below copied from Craig R. McClanahan's InvokerServlet */ private static final long serialVersionUID = 1L; private static final Set DEFAULT_SUPER_METHODS = new HashSet(); static { DEFAULT_SUPER_METHODS.add("HEAD"); DEFAULT_SUPER_METHODS.add("OPTIONS"); DEFAULT_SUPER_METHODS.add("TRACE"); } /** * The CGI search path will start at * webAppRootDir + File.separator + cgiPathPrefix * (or webAppRootDir alone if cgiPathPrefix is * null) */ private String cgiPathPrefix = null; /** the executable to use with the script */ private String cgiExecutable = "perl"; /** additional arguments for the executable */ private List cgiExecutableArgs = null; /** the encoding to use for parameters */ private String parameterEncoding = System.getProperty("file.encoding", "UTF-8"); /* The HTTP methods this Servlet will pass to the CGI script */ private Set cgiMethods = new HashSet(); private boolean cgiMethodsAll = false; /** * The time (in milliseconds) to wait for the reading of stderr to complete * before terminating the CGI process. */ private long stderrTimeout = 2000; /** * The regular expression used to select HTTP headers to be passed to the * CGI process as environment variables. The name of the environment * variable will be the name of the HTTP header converter to upper case, * prefixed with HTTP_ and with all - characters * converted to _. */ private Pattern envHttpHeadersPattern = Pattern.compile( "ACCEPT[-0-9A-Z]*|CACHE-CONTROL|COOKIE|HOST|IF-[-0-9A-Z]*|REFERER|USER-AGENT"); /** object used to ensure multiple threads don't try to expand same file */ private static final Object expandFileLock = new Object(); /** the shell environment variables to be passed to the CGI script */ private final Hashtable shellEnv = new Hashtable(); /** * Enable creation of script command line arguments from query-string. * See https://tools.ietf.org/html/rfc3875#section-4.4 * 4.4. The Script Command Line */ private boolean enableCmdLineArguments = true; /** * Sets instance variables. *

* Modified from Craig R. McClanahan's InvokerServlet *

* * @param config a ServletConfig object * containing the servlet's * configuration and initialization * parameters * * @exception ServletException if an exception has occurred that * interferes with the servlet's normal * operation */ @Override public void init(ServletConfig config) throws ServletException { super.init(config); // Set our properties from the initialization parameters cgiPathPrefix = getServletConfig().getInitParameter("cgiPathPrefix"); boolean passShellEnvironment = Boolean.parseBoolean(getServletConfig().getInitParameter("passShellEnvironment")); if (passShellEnvironment) { shellEnv.putAll(System.getenv()); } Enumeration e = config.getInitParameterNames(); while(e.hasMoreElements()) { String initParamName = e.nextElement(); if (initParamName.startsWith("environment-variable-")) { if (initParamName.length() == 21) { throw new ServletException(sm.getString("cgiServlet.emptyEnvVarName")); } shellEnv.put(initParamName.substring(21), config.getInitParameter(initParamName)); } } if (getServletConfig().getInitParameter("executable") != null) { cgiExecutable = getServletConfig().getInitParameter("executable"); } if (getServletConfig().getInitParameter("executable-arg-1") != null) { List args = new ArrayList(); for (int i = 1;; i++) { String arg = getServletConfig().getInitParameter( "executable-arg-" + i); if (arg == null) { break; } args.add(arg); } cgiExecutableArgs = args; } if (getServletConfig().getInitParameter("parameterEncoding") != null) { parameterEncoding = getServletConfig().getInitParameter("parameterEncoding"); } if (getServletConfig().getInitParameter("stderrTimeout") != null) { stderrTimeout = Long.parseLong(getServletConfig().getInitParameter( "stderrTimeout")); } if (getServletConfig().getInitParameter("envHttpHeaders") != null) { envHttpHeadersPattern = Pattern.compile(getServletConfig().getInitParameter("envHttpHeaders")); } if (getServletConfig().getInitParameter("enableCmdLineArguments") != null) { enableCmdLineArguments = Boolean.parseBoolean(config.getInitParameter("enableCmdLineArguments")); } if (getServletConfig().getInitParameter("cgiMethods") != null) { String paramValue = getServletConfig().getInitParameter("cgiMethods"); paramValue.trim(); if ("*".equals(paramValue)) { cgiMethodsAll = true; } else { String[] methods = paramValue.split(","); for (String method : methods) { String trimmedMethod = method.trim(); cgiMethods.add(trimmedMethod); } } } else { cgiMethods.add("GET"); cgiMethods.add("POST"); } } /** * Logs important Servlet API and container information. * *

* Copied from SnoopAllServlet by Craig R. McClanahan *

* * @param out Unused * @param req HttpServletRequest object used as source of information * @param res Unused * * @exception IOException if a write operation exception occurs * * @deprecated Use {@link #printServletEnvironment(HttpServletRequest)}. * This will be removed in Tomcat 8.5.X onwards */ @Deprecated protected void printServletEnvironment(ServletOutputStream out, HttpServletRequest req, HttpServletResponse res) throws IOException { printServletEnvironment(req); } /** * Logs important Servlet API and container information. * *

* Based on SnoopAllServlet by Craig R. McClanahan *

* * @param req HttpServletRequest object used as source of information * * @exception IOException if a write operation exception occurs */ private void printServletEnvironment(HttpServletRequest req) throws IOException { // Document the properties from ServletRequest log.trace("ServletRequest Properties"); Enumeration attrs = req.getAttributeNames(); while (attrs.hasMoreElements()) { String attr = attrs.nextElement(); log.trace("Request Attribute: " + attr + ": [ " + req.getAttribute(attr) +"]"); } log.trace("Character Encoding: [" + req.getCharacterEncoding() + "]"); log.trace("Content Length: [" + req.getContentLength() + "]"); log.trace("Content Type: [" + req.getContentType() + "]"); Enumeration locales = req.getLocales(); while (locales.hasMoreElements()) { Locale locale = locales.nextElement(); log.trace("Locale: [" +locale + "]"); } Enumeration params = req.getParameterNames(); while (params.hasMoreElements()) { String param = params.nextElement(); for (String value : req.getParameterValues(param)) { log.trace("Request Parameter: " + param + ": [" + value + "]"); } } log.trace("Protocol: [" + req.getProtocol() + "]"); log.trace("Remote Address: [" + req.getRemoteAddr() + "]"); log.trace("Remote Host: [" + req.getRemoteHost() + "]"); log.trace("Scheme: [" + req.getScheme() + "]"); log.trace("Secure: [" + req.isSecure() + "]"); log.trace("Server Name: [" + req.getServerName() + "]"); log.trace("Server Port: [" + req.getServerPort() + "]"); // Document the properties from HttpServletRequest log.trace("HttpServletRequest Properties"); log.trace("Auth Type: [" + req.getAuthType() + "]"); log.trace("Context Path: [" + req.getContextPath() + "]"); Cookie cookies[] = req.getCookies(); if (cookies != null) { for (Cookie cookie : cookies) { log.trace("Cookie: " + cookie.getName() + ": [" + cookie.getValue() + "]"); } } Enumeration headers = req.getHeaderNames(); while (headers.hasMoreElements()) { String header = headers.nextElement(); log.trace("HTTP Header: " + header + ": [" + req.getHeader(header) + "]"); } log.trace("Method: [" + req.getMethod() + "]"); log.trace("Path Info: [" + req.getPathInfo() + "]"); log.trace("Path Translated: [" + req.getPathTranslated() + "]"); log.trace("Query String: [" + req.getQueryString() + "]"); log.trace("Remote User: [" + req.getRemoteUser() + "]"); log.trace("Requested Session ID: [" + req.getRequestedSessionId() + "]"); log.trace("Requested Session ID From Cookie: [" + req.isRequestedSessionIdFromCookie() + "]"); log.trace("Requested Session ID From URL: [" + req.isRequestedSessionIdFromURL() + "]"); log.trace("Requested Session ID Valid: [" + req.isRequestedSessionIdValid() + "]"); log.trace("Request URI: [" + req.getRequestURI() + "]"); log.trace("Servlet Path: [" + req.getServletPath() + "]"); log.trace("User Principal: [" + req.getUserPrincipal() + "]"); // Process the current session (if there is one) HttpSession session = req.getSession(false); if (session != null) { // Document the session properties log.trace("HttpSession Properties"); log.trace("ID: [" + session.getId() + "]"); log.trace("Creation Time: [" + new Date(session.getCreationTime()) + "]"); log.trace("Last Accessed Time: [" + new Date(session.getLastAccessedTime()) + "]"); log.trace("Max Inactive Interval: [" + session.getMaxInactiveInterval() + "]"); // Document the session attributes attrs = session.getAttributeNames(); while (attrs.hasMoreElements()) { String attr = attrs.nextElement(); log.trace("Session Attribute: " + attr + ": [" + session.getAttribute(attr) + "]"); } } // Document the servlet configuration properties log.trace("ServletConfig Properties"); log.trace("Servlet Name: [" + getServletConfig().getServletName() + "]"); // Document the servlet configuration initialization parameters params = getServletConfig().getInitParameterNames(); while (params.hasMoreElements()) { String param = params.nextElement(); String value = getServletConfig().getInitParameter(param); log.trace("Servlet Init Param: " + param + ": [" + value + "]"); } // Document the servlet context properties log.trace("ServletContext Properties"); log.trace("Major Version: [" + getServletContext().getMajorVersion() + "]"); log.trace("Minor Version: [" + getServletContext().getMinorVersion() + "]"); log.trace("Real Path for '/': [" + getServletContext().getRealPath("/") + "]"); log.trace("Server Info: [" + getServletContext().getServerInfo() + "]"); // Document the servlet context initialization parameters log.trace("ServletContext Initialization Parameters"); params = getServletContext().getInitParameterNames(); while (params.hasMoreElements()) { String param = params.nextElement(); String value = getServletContext().getInitParameter(param); log.trace("Servlet Context Init Param: " + param + ": [" + value + "]"); } // Document the servlet context attributes log.trace("ServletContext Attributes"); attrs = getServletContext().getAttributeNames(); while (attrs.hasMoreElements()) { String attr = attrs.nextElement(); log.trace("Servlet Context Attribute: " + attr + ": [" + getServletContext().getAttribute(attr) + "]"); } } @Override protected void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { String method = req.getMethod(); if (cgiMethodsAll || cgiMethods.contains(method)) { doGet(req, res); } else if (DEFAULT_SUPER_METHODS.contains(method)){ // If the CGI servlet is explicitly configured to handle one of // these methods it will be handled in the previous condition super.service(req, res); } else { // Unsupported method res.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED); } } /** * Provides CGI Gateway service. * * @param req HttpServletRequest passed in by servlet container * @param res HttpServletResponse passed in by servlet container * * @exception ServletException if a servlet-specific exception occurs * @exception IOException if a read/write exception occurs */ @Override protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { CGIEnvironment cgiEnv = new CGIEnvironment(req, getServletContext()); if (cgiEnv.isValid()) { CGIRunner cgi = new CGIRunner(cgiEnv.getCommand(), cgiEnv.getEnvironment(), cgiEnv.getWorkingDirectory(), cgiEnv.getParameters()); if ("POST".equals(req.getMethod())) { cgi.setInput(req.getInputStream()); } cgi.setResponse(res); cgi.run(); } else { res.sendError(404); } if (log.isTraceEnabled()) { String[] cgiEnvLines = cgiEnv.toString().split(LINE_SEP); for (String cgiEnvLine : cgiEnvLines) { log.trace(cgiEnvLine); } printServletEnvironment(req); } } @Override protected void doOptions(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { // Note: This method will never be called if cgiMethods is "*" so that // case does nto need to be handled here. Set allowedMethods = new HashSet(); allowedMethods.addAll(cgiMethods); allowedMethods.addAll(CGIServlet.DEFAULT_SUPER_METHODS); StringBuilder headerValue = new StringBuilder(); for (String method : allowedMethods) { headerValue.append(method); headerValue.append(','); } // Remove trailing comma headerValue.deleteCharAt(headerValue.length() - 1); res.setHeader("allow", headerValue.toString()); } /** * Behaviour depends on the status code. * * Status < 400 - Calls setStatus. Returns false. CGI servlet will provide * the response body. * Status >= 400 - Calls sendError(status), returns true. Standard error * page mechanism will provide the response body. */ private boolean setStatus(HttpServletResponse response, int status) throws IOException { if (status >= HttpServletResponse.SC_BAD_REQUEST) { response.sendError(status); return true; } else { response.setStatus(status); return false; } } /** * Encapsulates the CGI environment and rules to derive * that environment from the servlet container and request information. */ protected class CGIEnvironment { /** context of the enclosing servlet */ private ServletContext context = null; /** context path of enclosing servlet */ private String contextPath = null; /** servlet URI of the enclosing servlet */ private String servletPath = null; /** pathInfo for the current request */ private String pathInfo = null; /** real file system directory of the enclosing servlet's web app */ private String webAppRootDir = null; /** tempdir for context - used to expand scripts in unexpanded wars */ private File tmpDir = null; /** derived cgi environment */ private Hashtable env = null; /** cgi command to be invoked */ private String command = null; /** cgi command's desired working directory */ private final File workingDirectory; /** cgi command's command line parameters */ private final ArrayList cmdLineParameters = new ArrayList(); /** whether or not this object is valid or not */ private final boolean valid; /** * Creates a CGIEnvironment and derives the necessary environment, * query parameters, working directory, cgi command, etc. * * @param req HttpServletRequest for information provided by * the Servlet API * @param context ServletContext for information provided by the * Servlet API * @throws IOException an IO error occurred */ protected CGIEnvironment(HttpServletRequest req, ServletContext context) throws IOException { setupFromContext(context); setupFromRequest(req); this.valid = setCGIEnvironment(req); if (this.valid) { workingDirectory = new File(command.substring(0, command.lastIndexOf(File.separator))); } else { workingDirectory = null; } } /** * Uses the ServletContext to set some CGI variables * * @param context ServletContext for information provided by the * Servlet API */ protected void setupFromContext(ServletContext context) { this.context = context; this.webAppRootDir = context.getRealPath("/"); this.tmpDir = (File) context.getAttribute(ServletContext.TEMPDIR); } /** * Uses the HttpServletRequest to set most CGI variables * * @param req HttpServletRequest for information provided by * the Servlet API * @throws UnsupportedEncodingException Unknown encoding */ protected void setupFromRequest(HttpServletRequest req) throws UnsupportedEncodingException { boolean isIncluded = false; // Look to see if this request is an include if (req.getAttribute( RequestDispatcher.INCLUDE_REQUEST_URI) != null) { isIncluded = true; } if (isIncluded) { this.contextPath = (String) req.getAttribute( RequestDispatcher.INCLUDE_CONTEXT_PATH); this.servletPath = (String) req.getAttribute( RequestDispatcher.INCLUDE_SERVLET_PATH); this.pathInfo = (String) req.getAttribute( RequestDispatcher.INCLUDE_PATH_INFO); } else { this.contextPath = req.getContextPath(); this.servletPath = req.getServletPath(); this.pathInfo = req.getPathInfo(); } // If getPathInfo() returns null, must be using extension mapping // In this case, pathInfo should be same as servletPath if (this.pathInfo == null) { this.pathInfo = this.servletPath; } // If the request method is GET, POST or HEAD and the query string // does not contain an unencoded "=" this is an indexed query. // The parsed query string becomes the command line parameters // for the cgi command. if (enableCmdLineArguments && (req.getMethod().equals("GET") || req.getMethod().equals("POST") || req.getMethod().equals("HEAD"))) { String qs; if (isIncluded) { qs = (String) req.getAttribute( RequestDispatcher.INCLUDE_QUERY_STRING); } else { qs = req.getQueryString(); } if (qs != null && qs.indexOf('=') == -1) { StringTokenizer qsTokens = new StringTokenizer(qs, "+"); while ( qsTokens.hasMoreTokens() ) { cmdLineParameters.add(URLDecoder.decode(qsTokens.nextToken(), parameterEncoding)); } } } } /** * Resolves core information about the cgi script. * *

* Example URI: *

*
 /servlet/cgigateway/dir1/realCGIscript/pathinfo1 
*
    *
  • path = $CATALINA_HOME/mywebapp/dir1/realCGIscript *
  • scriptName = /servlet/cgigateway/dir1/realCGIscript *
  • cgiName = /dir1/realCGIscript *
  • name = realCGIscript *
*

* CGI search algorithm: search the real path below * <my-webapp-root> and find the first non-directory in * the getPathTranslated("/"), reading/searching from left-to-right. *

*

* The CGI search path will start at * webAppRootDir + File.separator + cgiPathPrefix * (or webAppRootDir alone if cgiPathPrefix is * null). *

*

* cgiPathPrefix is defined by setting * this servlet's cgiPathPrefix init parameter * *

* * @param pathInfo String from HttpServletRequest.getPathInfo() * @param webAppRootDir String from context.getRealPath("/") * @param contextPath String as from * HttpServletRequest.getContextPath() * @param servletPath String as from * HttpServletRequest.getServletPath() * @param cgiPathPrefix subdirectory of webAppRootDir below which * the web app's CGIs may be stored; can be null. * The CGI search path will start at * webAppRootDir + File.separator + cgiPathPrefix * (or webAppRootDir alone if cgiPathPrefix is * null). cgiPathPrefix is defined by setting * the servlet's cgiPathPrefix init parameter. * * * @return *
    *
  • * path - full file-system path to valid cgi script, * or null if no cgi was found *
  • * scriptName - * CGI variable SCRIPT_NAME; the full URL path * to valid cgi script or null if no cgi was * found *
  • * cgiName - servlet pathInfo fragment corresponding to * the cgi script itself, or null if not found *
  • * name - simple name (no directories) of the * cgi script, or null if no cgi was found *
*/ protected String[] findCGI(String pathInfo, String webAppRootDir, String contextPath, String servletPath, String cgiPathPrefix) { String path = null; String name = null; String scriptname = null; if (webAppRootDir != null && webAppRootDir.lastIndexOf(File.separator) == (webAppRootDir.length() - 1)) { //strip the trailing "/" from the webAppRootDir webAppRootDir = webAppRootDir.substring(0, (webAppRootDir.length() - 1)); } if (cgiPathPrefix != null) { webAppRootDir = webAppRootDir + File.separator + cgiPathPrefix; } if (log.isDebugEnabled()) { log.debug(sm.getString("cgiServlet.find.path", pathInfo, webAppRootDir)); } File currentLocation = new File(webAppRootDir); StringTokenizer dirWalker = new StringTokenizer(pathInfo, "/"); if (log.isDebugEnabled()) { log.debug(sm.getString("cgiServlet.find.location", currentLocation.getAbsolutePath())); } StringBuilder cginameBuilder = new StringBuilder(); while (!currentLocation.isFile() && dirWalker.hasMoreElements()) { String nextElement = (String) dirWalker.nextElement(); currentLocation = new File(currentLocation, nextElement); cginameBuilder.append('/').append(nextElement); if (log.isDebugEnabled()) { log.debug(sm.getString("cgiServlet.find.location", currentLocation.getAbsolutePath())); } } String cginame = cginameBuilder.toString(); if (!currentLocation.isFile()) { return new String[] { null, null, null, null }; } path = currentLocation.getAbsolutePath(); name = currentLocation.getName(); if (servletPath.startsWith(cginame)) { scriptname = contextPath + cginame; } else { scriptname = contextPath + servletPath + cginame; } if (log.isDebugEnabled()) { log.debug(sm.getString("cgiServlet.find.found", name, path, scriptname, cginame)); } return new String[] { path, scriptname, cginame, name }; } /** * Constructs the CGI environment to be supplied to the invoked CGI * script; relies heavily on Servlet API methods and findCGI * * @param req request associated with the CGI * Invocation * * @return true if environment was set OK, false if there * was a problem and no environment was set * @throws IOException an IO error occurred */ protected boolean setCGIEnvironment(HttpServletRequest req) throws IOException { /* * This method is slightly ugly; c'est la vie. * "You cannot stop [ugliness], you can only hope to contain [it]" * (apologies to Marv Albert regarding MJ) */ Hashtable envp = new Hashtable(); // Add the shell environment variables (if any) envp.putAll(shellEnv); // Add the CGI environment variables String sPathInfoOrig = null; String sPathInfoCGI = null; String sPathTranslatedCGI = null; String sCGIFullPath = null; String sCGIScriptName = null; String sCGIFullName = null; String sCGIName = null; String[] sCGINames; sPathInfoOrig = this.pathInfo; sPathInfoOrig = sPathInfoOrig == null ? "" : sPathInfoOrig; if (webAppRootDir == null ) { // The app has not been deployed in exploded form webAppRootDir = tmpDir.toString(); expandCGIScript(); } sCGINames = findCGI(sPathInfoOrig, webAppRootDir, contextPath, servletPath, cgiPathPrefix); sCGIFullPath = sCGINames[0]; sCGIScriptName = sCGINames[1]; sCGIFullName = sCGINames[2]; sCGIName = sCGINames[3]; if (sCGIFullPath == null || sCGIScriptName == null || sCGIFullName == null || sCGIName == null) { return false; } envp.put("SERVER_SOFTWARE", "TOMCAT"); envp.put("SERVER_NAME", nullsToBlanks(req.getServerName())); envp.put("GATEWAY_INTERFACE", "CGI/1.1"); envp.put("SERVER_PROTOCOL", nullsToBlanks(req.getProtocol())); int port = req.getServerPort(); Integer iPort = (port == 0 ? Integer.valueOf(-1) : Integer.valueOf(port)); envp.put("SERVER_PORT", iPort.toString()); envp.put("REQUEST_METHOD", nullsToBlanks(req.getMethod())); envp.put("REQUEST_URI", nullsToBlanks(req.getRequestURI())); /*- * PATH_INFO should be determined by using sCGIFullName: * 1) Let sCGIFullName not end in a "/" (see method findCGI) * 2) Let sCGIFullName equal the pathInfo fragment which * corresponds to the actual cgi script. * 3) Thus, PATH_INFO = request.getPathInfo().substring( * sCGIFullName.length()) * * (see method findCGI, where the real work is done) * */ if (pathInfo == null || (pathInfo.substring(sCGIFullName.length()).length() <= 0)) { sPathInfoCGI = ""; } else { sPathInfoCGI = pathInfo.substring(sCGIFullName.length()); } envp.put("PATH_INFO", sPathInfoCGI); /*- * PATH_TRANSLATED must be determined after PATH_INFO (and the * implied real cgi-script) has been taken into account. * * The following example demonstrates: * * servlet info = /servlet/cgigw/dir1/dir2/cgi1/trans1/trans2 * cgifullpath = /servlet/cgigw/dir1/dir2/cgi1 * path_info = /trans1/trans2 * webAppRootDir = servletContext.getRealPath("/") * * path_translated = servletContext.getRealPath("/trans1/trans2") * * That is, PATH_TRANSLATED = webAppRootDir + sPathInfoCGI * (unless sPathInfoCGI is null or blank, then the CGI * specification dictates that the PATH_TRANSLATED metavariable * SHOULD NOT be defined. * */ if (!("".equals(sPathInfoCGI))) { sPathTranslatedCGI = context.getRealPath(sPathInfoCGI); } if (sPathTranslatedCGI == null || "".equals(sPathTranslatedCGI)) { //NOOP } else { envp.put("PATH_TRANSLATED", nullsToBlanks(sPathTranslatedCGI)); } envp.put("SCRIPT_NAME", nullsToBlanks(sCGIScriptName)); envp.put("QUERY_STRING", nullsToBlanks(req.getQueryString())); envp.put("REMOTE_HOST", nullsToBlanks(req.getRemoteHost())); envp.put("REMOTE_ADDR", nullsToBlanks(req.getRemoteAddr())); envp.put("AUTH_TYPE", nullsToBlanks(req.getAuthType())); envp.put("REMOTE_USER", nullsToBlanks(req.getRemoteUser())); envp.put("REMOTE_IDENT", ""); //not necessary for full compliance envp.put("CONTENT_TYPE", nullsToBlanks(req.getContentType())); /* Note CGI spec says CONTENT_LENGTH must be NULL ("") or undefined * if there is no content, so we cannot put 0 or -1 in as per the * Servlet API spec. */ int contentLength = req.getContentLength(); String sContentLength = (contentLength <= 0 ? "" : Integer.toString(contentLength)); envp.put("CONTENT_LENGTH", sContentLength); Enumeration headers = req.getHeaderNames(); String header = null; while (headers.hasMoreElements()) { header = null; header = headers.nextElement().toUpperCase(Locale.ENGLISH); //REMIND: rewrite multiple headers as if received as single //REMIND: change character set //REMIND: I forgot what the previous REMIND means if (envHttpHeadersPattern.matcher(header).matches()) { envp.put("HTTP_" + header.replace('-', '_'), req.getHeader(header)); } } File fCGIFullPath = new File(sCGIFullPath); command = fCGIFullPath.getCanonicalPath(); envp.put("X_TOMCAT_SCRIPT_PATH", command); //for kicks envp.put("SCRIPT_FILENAME", command); //for PHP this.env = envp; return true; } /** * Extracts requested resource from web app archive to context work * directory to enable CGI script to be executed. */ protected void expandCGIScript() { StringBuilder srcPath = new StringBuilder(); StringBuilder destPath = new StringBuilder(); InputStream is = null; // paths depend on mapping if (cgiPathPrefix == null ) { srcPath.append(pathInfo); is = context.getResourceAsStream(srcPath.toString()); destPath.append(tmpDir); destPath.append(pathInfo); } else { // essentially same search algorithm as findCGI() srcPath.append(cgiPathPrefix); StringTokenizer pathWalker = new StringTokenizer (pathInfo, "/"); // start with first element while (pathWalker.hasMoreElements() && (is == null)) { srcPath.append("/"); srcPath.append(pathWalker.nextElement()); is = context.getResourceAsStream(srcPath.toString()); } destPath.append(tmpDir); destPath.append("/"); destPath.append(srcPath); } if (is == null) { // didn't find anything, give up now log.warn(sm.getString("cgiServlet.expandNotFound", srcPath)); return; } File f = new File(destPath.toString()); if (f.exists()) { try { is.close(); } catch (IOException e) { log.warn(sm.getString("cgiServlet.expandCloseFail", srcPath), e); } // Don't need to expand if it already exists return; } // create directories File dir = f.getParentFile(); if (!dir.mkdirs() && !dir.isDirectory()) { log.warn(sm.getString("cgiServlet.expandCreateDirFail", dir.getAbsolutePath())); return; } try { synchronized (expandFileLock) { // make sure file doesn't exist if (f.exists()) { return; } // create file if (!f.createNewFile()) { return; } FileOutputStream fos = new FileOutputStream(f); try { // copy data IOTools.flow(is, fos); } finally { try { is.close(); } catch (IOException e) { log.warn(sm.getString("cgiServlet.expandError"), e); } fos.close(); } if (log.isDebugEnabled()) { log.debug(sm.getString("cgiServlet.expandOk", srcPath, destPath)); } } } catch (IOException ioe) { log.warn(sm.getString("cgiServlet.expandFail", srcPath, destPath), ioe); // delete in case file is corrupted if (f.exists()) { if (!f.delete()) { log.warn(sm.getString("cgiServlet.expandDeleteFail", f.getAbsolutePath())); } } } } /** * Returns important CGI environment information in a multi-line text * format. * * @return CGI environment info */ @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append("CGIEnvironment Info:"); sb.append(LINE_SEP); if (isValid()) { sb.append("Validity: [true]"); sb.append(LINE_SEP); sb.append("Environment values:"); sb.append(LINE_SEP); for (Entry entry : env.entrySet()) { sb.append(" "); sb.append(entry.getKey()); sb.append(": ["); sb.append(blanksToString(entry.getValue(), "will be set to blank")); sb.append("]"); sb.append(LINE_SEP); } sb.append("Derived Command :["); sb.append(nullsToBlanks(command)); sb.append("]"); sb.append(LINE_SEP); sb.append("Working Directory: ["); if (workingDirectory != null) { sb.append(workingDirectory.toString()); } sb.append("]"); sb.append(LINE_SEP); sb.append("Command Line Params:"); sb.append(LINE_SEP); for (String param : cmdLineParameters) { sb.append(" ["); sb.append(param); sb.append("]"); sb.append(LINE_SEP); } } else { sb.append("Validity: [false]"); sb.append(LINE_SEP); sb.append("CGI script not found or not specified."); sb.append(LINE_SEP); sb.append("Check the HttpServletRequest pathInfo property to see if it is what "); sb.append(LINE_SEP); sb.append("you meant it to be. You must specify an existent and executable file "); sb.append(LINE_SEP); sb.append("as part of the path-info."); sb.append(LINE_SEP); } return sb.toString(); } /** * Gets derived command string * * @return command string * */ protected String getCommand() { return command; } /** * Gets derived CGI working directory * * @return working directory * */ protected File getWorkingDirectory() { return workingDirectory; } /** * Gets derived CGI environment * * @return CGI environment * */ protected Hashtable getEnvironment() { return env; } /** * Gets derived CGI query parameters * * @return CGI query parameters * */ protected ArrayList getParameters() { return cmdLineParameters; } /** * Gets validity status * * @return true if this environment is valid, false * otherwise * */ protected boolean isValid() { return valid; } /** * Converts null strings to blank strings ("") * * @param s string to be converted if necessary * @return a non-null string, either the original or the empty string * ("") if the original was null */ protected String nullsToBlanks(String s) { return nullsToString(s, ""); } /** * Converts null strings to another string * * @param couldBeNull string to be converted if necessary * @param subForNulls string to return instead of a null string * @return a non-null string, either the original or the substitute * string if the original was null */ protected String nullsToString(String couldBeNull, String subForNulls) { return (couldBeNull == null ? subForNulls : couldBeNull); } /** * Converts blank strings to another string * * @param couldBeBlank string to be converted if necessary * @param subForBlanks string to return instead of a blank string * @return a non-null string, either the original or the substitute * string if the original was null or empty ("") */ protected String blanksToString(String couldBeBlank, String subForBlanks) { return (("".equals(couldBeBlank) || couldBeBlank == null) ? subForBlanks : couldBeBlank); } } //class CGIEnvironment /** * Encapsulates the knowledge of how to run a CGI script, given the * script's desired environment and (optionally) input/output streams * *

* * Exposes a run method used to actually invoke the * CGI. * *

*

* * The CGI environment and settings are derived from the information * passed to the constructor. * *

*

* * The input and output streams can be set by the setInput * and setResponse methods, respectively. *

*/ protected class CGIRunner { /** script/command to be executed */ private final String command; /** environment used when invoking the cgi script */ private final Hashtable env; /** working directory used when invoking the cgi script */ private final File wd; /** command line parameters to be passed to the invoked script */ private final ArrayList params; /** stdin to be passed to cgi script */ private InputStream stdin = null; /** response object used to set headers & get output stream */ private HttpServletResponse response = null; /** boolean tracking whether this object has enough info to run() */ private boolean readyToRun = false; /** * Creates a CGIRunner and initializes its environment, working * directory, and query parameters. *
* Input/output streams (optional) are set using the * setInput and setResponse methods, * respectively. * * @param command string full path to command to be executed * @param env Hashtable with the desired script environment * @param wd File with the script's desired working directory * @param params ArrayList with the script's query command line * parameters as strings */ protected CGIRunner(String command, Hashtable env, File wd, ArrayList params) { this.command = command; this.env = env; this.wd = wd; this.params = params; updateReadyStatus(); } /** * Checks and sets ready status */ protected void updateReadyStatus() { if (command != null && env != null && wd != null && params != null && response != null) { readyToRun = true; } else { readyToRun = false; } } /** * Gets ready status * * @return false if not ready (run will throw * an exception), true if ready */ protected boolean isReady() { return readyToRun; } /** * Sets HttpServletResponse object used to set headers and send * output to * * @param response HttpServletResponse to be used * */ protected void setResponse(HttpServletResponse response) { this.response = response; updateReadyStatus(); } /** * Sets standard input to be passed on to the invoked cgi script * * @param stdin InputStream to be used * */ protected void setInput(InputStream stdin) { this.stdin = stdin; updateReadyStatus(); } /** * Converts a Hashtable to a String array by converting each * key/value pair in the Hashtable to a String in the form * "key=value" (hashkey + "=" + hash.get(hashkey).toString()) * * @param h Hashtable to convert * * @return converted string array * * @exception NullPointerException if a hash key has a null value * */ protected String[] hashToStringArray(Hashtable h) throws NullPointerException { Vector v = new Vector(); Enumeration e = h.keys(); while (e.hasMoreElements()) { String k = e.nextElement(); v.add(k + "=" + h.get(k).toString()); } String[] strArr = new String[v.size()]; v.copyInto(strArr); return strArr; } /** * Executes a CGI script with the desired environment, current working * directory, and input/output streams * *

* This implements the following CGI specification recommendations: *

*
    *
  • Servers SHOULD provide the "query" component of * the script-URI as command-line arguments to scripts if it * does not contain any unencoded "=" characters and the * command-line arguments can be generated in an unambiguous * manner. *
  • Servers SHOULD set the AUTH_TYPE metavariable to the value * of the "auth-scheme" token of the * "Authorization" if it was supplied as part of the * request header. See getCGIEnvironment method. *
  • Where applicable, servers SHOULD set the current working * directory to the directory in which the script is located * before invoking it. *
  • Server implementations SHOULD define their behavior for the * following cases: *
      *
    • Allowed characters in pathInfo: This implementation * does not allow ASCII NUL nor any character which cannot * be URL-encoded according to internet standards; *
    • Allowed characters in path segments: This * implementation does not allow non-terminal NULL * segments in the the path -- IOExceptions may be thrown; *
    • "." and ".." path * segments: * This implementation does not allow "." and * ".." in the the path, and such characters * will result in an IOException being thrown (this should * never happen since Tomcat normalises the requestURI * before determining the contextPath, servletPath and * pathInfo); *
    • Implementation limitations: This implementation * does not impose any limitations except as documented * above. This implementation may be limited by the * servlet container used to house this implementation. * In particular, all the primary CGI variable values * are derived either directly or indirectly from the * container's implementation of the Servlet API methods. *
    *
* * @exception IOException if problems during reading/writing occur * * @see java.lang.Runtime#exec(String command, String[] envp, * File dir) */ protected void run() throws IOException { /* * REMIND: this method feels too big; should it be re-written? */ if (!isReady()) { throw new IOException(this.getClass().getName() + ": not ready to run."); } if (log.isDebugEnabled()) { log.debug("envp: [" + env + "], command: [" + command + "]"); } if ((command.indexOf(File.separator + "." + File.separator) >= 0) || (command.indexOf(File.separator + "..") >= 0) || (command.indexOf(".." + File.separator) >= 0)) { throw new IOException(this.getClass().getName() + "Illegal Character in CGI command " + "path ('.' or '..') detected. Not " + "running CGI [" + command + "]."); } /* original content/structure of this section taken from * http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4216884 * with major modifications by Martin Dengler */ Runtime rt = null; BufferedReader cgiHeaderReader = null; InputStream cgiOutput = null; BufferedReader commandsStdErr = null; Thread errReaderThread = null; BufferedOutputStream commandsStdIn = null; Process proc = null; int bufRead = -1; List cmdAndArgs = new ArrayList(); if (cgiExecutable.length() != 0) { cmdAndArgs.add(cgiExecutable); } if (cgiExecutableArgs != null) { cmdAndArgs.addAll(cgiExecutableArgs); } cmdAndArgs.add(command); cmdAndArgs.addAll(params); try { rt = Runtime.getRuntime(); proc = rt.exec( cmdAndArgs.toArray(new String[cmdAndArgs.size()]), hashToStringArray(env), wd); String sContentLength = env.get("CONTENT_LENGTH"); if(!"".equals(sContentLength)) { commandsStdIn = new BufferedOutputStream(proc.getOutputStream()); IOTools.flow(stdin, commandsStdIn); commandsStdIn.flush(); commandsStdIn.close(); } /* we want to wait for the process to exit, Process.waitFor() * is useless in our situation; see * http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4223650 */ boolean isRunning = true; commandsStdErr = new BufferedReader (new InputStreamReader(proc.getErrorStream())); final BufferedReader stdErrRdr = commandsStdErr ; errReaderThread = new Thread() { @Override public void run () { sendToLog(stdErrRdr); } }; errReaderThread.start(); InputStream cgiHeaderStream = new HTTPHeaderInputStream(proc.getInputStream()); cgiHeaderReader = new BufferedReader(new InputStreamReader(cgiHeaderStream)); // Need to be careful here. If sendError() is called the // response body should be provided by the standard error page // process. But, if the output of the CGI process isn't read // then that process can hang. boolean skipBody = false; while (isRunning) { try { //set headers String line = null; while (((line = cgiHeaderReader.readLine()) != null) && !("".equals(line))) { if (log.isTraceEnabled()) { log.trace("addHeader(\"" + line + "\")"); } if (line.startsWith("HTTP")) { skipBody = setStatus(response, getSCFromHttpStatusLine(line)); } else if (line.indexOf(':') >= 0) { String header = line.substring(0, line.indexOf(':')).trim(); String value = line.substring(line.indexOf(':') + 1).trim(); if (header.equalsIgnoreCase("status")) { skipBody = setStatus(response, getSCFromCGIStatusHeader(value)); } else { response.addHeader(header , value); } } else { log.info(sm.getString("cgiServlet.runBadHeader", line)); } } //write output byte[] bBuf = new byte[2048]; OutputStream out = response.getOutputStream(); cgiOutput = proc.getInputStream(); try { while (!skipBody && (bufRead = cgiOutput.read(bBuf)) != -1) { if (log.isTraceEnabled()) { log.trace("output " + bufRead + " bytes of data"); } out.write(bBuf, 0, bufRead); } } finally { // Attempt to consume any leftover byte if something bad happens, // such as a socket disconnect on the servlet side; otherwise, the // external process could hang if (bufRead != -1) { while ((bufRead = cgiOutput.read(bBuf)) != -1) { // NOOP - just read the data } } } proc.exitValue(); // Throws exception if alive isRunning = false; } catch (IllegalThreadStateException e) { try { Thread.sleep(500); } catch (InterruptedException ignored) { // Ignore } } } //replacement for Process.waitFor() } catch (IOException e){ log.warn(sm.getString("cgiServlet.runFail"), e); throw e; } finally { // Close the header reader if (cgiHeaderReader != null) { try { cgiHeaderReader.close(); } catch (IOException ioe) { log.warn(sm.getString("cgiServlet.runHeaderReaderFail"), ioe); } } // Close the output stream if used if (cgiOutput != null) { try { cgiOutput.close(); } catch (IOException ioe) { log.warn(sm.getString("cgiServlet.runOutputStreamFail"), ioe); } } // Make sure the error stream reader has finished if (errReaderThread != null) { try { errReaderThread.join(stderrTimeout); } catch (InterruptedException e) { log.warn(sm.getString("cgiServlet.runReaderInterrupt")); } } if (proc != null){ proc.destroy(); proc = null; } } } /** * Parses the Status-Line and extracts the status code. * * @param line The HTTP Status-Line (RFC2616, section 6.1) * @return The extracted status code or the code representing an * internal error if a valid status code cannot be extracted. */ private int getSCFromHttpStatusLine(String line) { int statusStart = line.indexOf(' ') + 1; if (statusStart < 1 || line.length() < statusStart + 3) { // Not a valid HTTP Status-Line log.warn(sm.getString("cgiServlet.runInvalidStatus", line)); return HttpServletResponse.SC_INTERNAL_SERVER_ERROR; } String status = line.substring(statusStart, statusStart + 3); int statusCode; try { statusCode = Integer.parseInt(status); } catch (NumberFormatException nfe) { // Not a valid status code log.warn(sm.getString("cgiServlet.runInvalidStatus", status)); return HttpServletResponse.SC_INTERNAL_SERVER_ERROR; } return statusCode; } /** * Parses the CGI Status Header value and extracts the status code. * * @param value The CGI Status value of the form * digit digit digit SP reason-phrase * @return The extracted status code or the code representing an * internal error if a valid status code cannot be extracted. */ private int getSCFromCGIStatusHeader(String value) { if (value.length() < 3) { // Not a valid status value log.warn(sm.getString("cgiServlet.runInvalidStatus", value)); return HttpServletResponse.SC_INTERNAL_SERVER_ERROR; } String status = value.substring(0, 3); int statusCode; try { statusCode = Integer.parseInt(status); } catch (NumberFormatException nfe) { // Not a valid status code log.warn(sm.getString("cgiServlet.runInvalidStatus", status)); return HttpServletResponse.SC_INTERNAL_SERVER_ERROR; } return statusCode; } private void sendToLog(BufferedReader rdr) { String line = null; int lineCount = 0 ; try { while ((line = rdr.readLine()) != null) { log.warn(sm.getString("cgiServlet.runStdErr", line)); lineCount++ ; } } catch (IOException e) { log.warn(sm.getString("cgiServlet.runStdErrFail"), e); } finally { try { rdr.close(); } catch (IOException e) { log.warn(sm.getString("cgiServlet.runStdErrFail"), e); } } if (lineCount > 0) { log.warn(sm.getString("cgiServlet.runStdErrCount", Integer.valueOf(lineCount))); } } } //class CGIRunner /** * This is an input stream specifically for reading HTTP headers. It reads * upto and including the two blank lines terminating the headers. It * allows the content to be read using bytes or characters as appropriate. */ protected static class HTTPHeaderInputStream extends InputStream { private static final int STATE_CHARACTER = 0; private static final int STATE_FIRST_CR = 1; private static final int STATE_FIRST_LF = 2; private static final int STATE_SECOND_CR = 3; private static final int STATE_HEADER_END = 4; private final InputStream input; private int state; HTTPHeaderInputStream(InputStream theInput) { input = theInput; state = STATE_CHARACTER; } /** * @see java.io.InputStream#read() */ @Override public int read() throws IOException { if (state == STATE_HEADER_END) { return -1; } int i = input.read(); // Update the state // State machine looks like this // // -------->-------- // | (CR) | // | | // CR1--->--- | // | | | // ^(CR) |(LF) | // | | | // CHAR--->--LF1--->--EOH // (LF) | (LF) | // |(CR) ^(LF) // | | // (CR2)-->--- if (i == 10) { // LF switch(state) { case STATE_CHARACTER: state = STATE_FIRST_LF; break; case STATE_FIRST_CR: state = STATE_FIRST_LF; break; case STATE_FIRST_LF: case STATE_SECOND_CR: state = STATE_HEADER_END; break; } } else if (i == 13) { // CR switch(state) { case STATE_CHARACTER: state = STATE_FIRST_CR; break; case STATE_FIRST_CR: state = STATE_HEADER_END; break; case STATE_FIRST_LF: state = STATE_SECOND_CR; break; } } else { state = STATE_CHARACTER; } return i; } } // class HTTPHeaderInputStream } //class CGIServlet




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