When redirecting JVM stdin/stdout to a named pipe (or even to the
same file), and the I/O stream is read or written using standard
Java I/O mechanism, for example, with BufferedReader.read() layered
above System.in and System.out (streams), an exception is thrown:


IOException: Bad File Number.

This is probably related to the same core issues affecting bug 4410664,
and seems to have to do with the way the JVM is dealing with file
descriptors, and some faulty logic about what file I/O means on UNIX.

For example, running the attached program without redirecting stdin/stdout
causes it to echo lines that are typed at the keyboard. This is correct,
expected and correct behavior. It behaves like typing 'cat' at the prompt,
with no arguments, would.

If the attached program is run with I/O redirected, the previously mentioned
exception is thrown. This was going to be the next-best workaround for the
problem in bug 4410664. The command to reproduce the problem (after compiling
the attachment) is:

% java PipeDream >pipe_to_something_that_talks_back 0>&1
Error reading from pipe
java.io.IOException: Bad file number

The attached program, PipeDream.java, is also included here:

import java.io.*;

public class PipeDream {

 public static void main(String args[]) {
  
      BufferedWriter dmPipeOut =
   new BufferedWriter(
new OutputStreamWriter(System.out));

      BufferedReader dmPipeIn =
            new BufferedReader(
new InputStreamReader(System.in));

      try {
         dmPipeOut.write("Some arbitrary string\n");
      } catch (Exception e) {
System.err.println("Error writing data to pipe");
System.err.println(e.toString());
System.exit(-1);
      }
     
      try {
String buf = null;
while ((buf = dmPipeIn.readLine()) != null)
      System.out.println(buf);
      } catch (Exception e) {
System.err.println("Error reading from pipe");
System.err.println(e.toString());
System.exit(-1);
      }
  }
}