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From amy...@apache.org
Subject cvs commit: jakarta-tomcat-catalina/catalina/src/share/org/apache/catalina/servlets CGIServlet.java
Date Mon, 26 Aug 2002 23:01:31 GMT
amyroh      2002/08/26 16:01:31

  Modified:    catalina/src/share/org/apache/catalina/servlets
                        CGIServlet.java
  Log:
  CGIServlet had problems in the case of a CGI script which prints a large
  amount of data to stdout; while the CGIServlet was waiting for the end of
  stderr, the CGI script would fill up the stdout buffer and then wait for it to be
  drained, causing a deadlock between the two processes.
  
  This patch solves this problem by having a single loop which
  reads stderr if it's ready, or stdout if ready.  If neither handle has queued
  data and the CGI script has exited, the servlet pauses a couple of times for
  half a second to make sure that all output has been delivered, then it exits.
  
  Fixes Bug 12041.  Patch submitted by Dave Glowacki (dglo@ssec.wisc.edu)
  
  Revision  Changes    Path
  1.2       +85 -51    jakarta-tomcat-catalina/catalina/src/share/org/apache/catalina/servlets/CGIServlet.java
  
  Index: CGIServlet.java
  ===================================================================
  RCS file: /home/cvs/jakarta-tomcat-catalina/catalina/src/share/org/apache/catalina/servlets/CGIServlet.java,v
  retrieving revision 1.1
  retrieving revision 1.2
  diff -u -r1.1 -r1.2
  --- CGIServlet.java	18 Jul 2002 16:47:39 -0000	1.1
  +++ CGIServlet.java	26 Aug 2002 23:01:31 -0000	1.2
  @@ -686,6 +686,7 @@
       /** For future testing use only; does nothing right now */
       public static void main(String[] args) {
           System.out.println("$Header$");
  +
       }
   
   
  @@ -1507,9 +1508,9 @@
            * </UL>
            * </p>
            *
  -         * For more information, see java.lang.Runtime#exec(String command, 
  +         * For more information, see java.lang.Runtime#exec(String command,
            * String[] envp, File dir)
  -         * 
  +         *
            * @exception IOException if problems during reading/writing occur
            *
            */
  @@ -1663,7 +1664,6 @@
                *                               bugParade/bugs/4223650.html
                */
   
  -            boolean isRunning = true;
               commandsStdOut = new BufferedReader
                   (new InputStreamReader(proc.getInputStream()));
               commandsStdErr = new BufferedReader
  @@ -1680,63 +1680,97 @@
                   //NOOP: no output will be written
               }
   
  +            boolean inHeader = true;
  +            int pauseCount = 0;
  +
  +            boolean isRunning = true;
  +
               while (isRunning) {
   
  -                try {
  -                    //read stderr first
  -                    cBuf = new char[1024];
  -                    while ((bufRead = commandsStdErr.read(cBuf)) != -1) {
  +                if (commandsStdErr != null && commandsStdErr.ready()) {
  +                    // about to read something; reset pause count
  +                    pauseCount = 0;
  +
  +                    bufRead = commandsStdErr.read(cBuf);
  +                    if (bufRead == -1) {
  +                        commandsStdErr.close();
  +                        commandsStdErr = null;
  +                        isRunning = (commandsStdOut != null);
  +                    } else {
                           if (servletContainerStdout != null) {
  -                            servletContainerStdout.write(cBuf, 0, bufRead);
  +                            if (inHeader) {
  +                                servletContainerStdout.write(cBuf, 0, bufRead);
  +                            } else {
  +                                log("runCGI: Throwing away StdErr \"" +
  +                                    new String(cBuf, 0, bufRead) + "\"");
  +                            }
                           }
                       }
  -
  -                    //set headers
  -                    String line = null;
  -                    while (((line = commandsStdOut.readLine()) != null)
  -                           && !("".equals(line))) {
  -                        if (debug >= 2) {
  -                            log("runCGI: addHeader(\"" + line + "\")");
  -                        }
  -                        if (line.startsWith("HTTP")) {
  -                            //TODO: should set status codes (NPH support)
  -                            /*
  -                             * response.setStatus(getStatusCode(line));
  -                             */
  +                } else if (commandsStdOut != null && commandsStdOut.ready()) {
  +                    // about to read something; reset pause count
  +                    pauseCount = 0;
  +
  +                    if (inHeader) {
  +                        //set headers
  +                        String line = commandsStdOut.readLine();
  +                        if (line == null || "".equals(line)) {
  +                            inHeader = false;
                           } else {
  -                            response.addHeader
  -                                (line.substring(0, line.indexOf(":")).trim(),
  -                                 line.substring(line.indexOf(":") + 1).trim());
  +                            if (debug >= 2) {
  +                                log("runCGI: addHeader(\"" + line + "\")");
  +                            }
  +                            if (line.startsWith("HTTP")) {
  +                                //TODO: should set status codes (NPH support)
  +                                /*
  +                                 * response.setStatus(getStatusCode(line));
  +                                 */
  +                            } else if (line.indexOf(":") >= 0) {
  +                                response.addHeader
  +                                    (line.substring(0, line.indexOf(":")).trim(),
  +                                     line.substring(line.indexOf(":") + 1).trim());
  +                            } else {
  +                                log("runCGI: bogus header line \"" + line + "\"");
  +                            }
                           }
  -                    }
   
  -                    //write output
  -                    cBuf = new char[1024];
  -                    while ((bufRead = commandsStdOut.read(cBuf)) != -1) {
  -                        if (servletContainerStdout != null) {
  -                            if (debug >= 4) {
  -                                log("runCGI: write(\"" + cBuf + "\")");
  +                    } else {
  +                        //write output
  +                        bufRead = commandsStdOut.read(cBuf);
  +                        if (bufRead == -1) {
  +                            commandsStdOut.close();
  +                            commandsStdOut = null;
  +                            isRunning = (commandsStdErr != null);
  +                        } else {
  +                            if (servletContainerStdout != null) {
  +                                if (debug >= 4) {
  +                                    log("runCGI: write(\"" + new String(cBuf, 0, bufRead)
+ "\")");
  +                                }
  +                                servletContainerStdout.write(cBuf, 0, bufRead);
                               }
  -                            servletContainerStdout.write(cBuf, 0, bufRead);
                           }
                       }
   
  -                    if (servletContainerStdout != null) {
  -                        servletContainerStdout.flush();
  -                    }
  -
  -                    proc.exitValue(); // Throws exception if alive
  -
  -                    isRunning = false;
  -
  -                } catch (IllegalThreadStateException e) {
  +                } else {
                       try {
  -                        Thread.currentThread().sleep(500);
  -                    } catch (InterruptedException ignored) {
  +                        int exitVal = proc.exitValue();
  +                        pauseCount++;
  +                        if (pauseCount > 2) {
  +                            isRunning = false;
  +                        } else {
  +                            // pause for half a second
  +                            try {
  +                                Thread.sleep(500);
  +                            } catch (InterruptedException ie) {
  +                            }
  +                        }
  +                    } catch (IllegalThreadStateException ex) {
                       }
                   }
  -            } //replacement for Process.waitFor()
   
  +                if (servletContainerStdout != null) {
  +                    servletContainerStdout.flush();
  +                }
  +            } //replacement for Process.waitFor()
   
           }
   
  
  
  

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