I'm having problems execing programs more than once.

The SIGCHLD handler only gets called with the first exec. Subsequent exec calls seem
to be handled differently. I can verify this because only the first exec prints the messages
pid 14494 status 0
Received sigchild for 14494 exit=0

I'll enclose a sample program and it's output.

ls.java:
public class ls {
    public ls(String file) {
        String args[] = new String[2];
        Process p;
        String buf;
        InputStream s;
        int length;

        args[0] = "/bin/ls";
        args[1] = file;
        try {
            p = Runtime.getRuntime().exec(args);
            s = p.getInputStream();
            DataInputStream din = new DataInputStream(s);

            while ((buf = din.readLine()) != null) {
                System.out.println(buf);
            }
        } catch (IOException e) {
            System.out.println("command failed.");
        }
        System.out.println("got to here");
    }

    public static void main(String args[]) {
        if (args.length == 0) {
            System.out.println("enter file");
        } else {
            System.out.println("first ls for " + args[0]);
            new ls(args[0]);
            System.out.println("second ls for " + args[0]);
            new ls(args[0]);
        }
    }
}

holiday% javac ls.java
holiday% java ls /tmp/foo
first ls for /tmp/foo
pid 14625 status 0
Received sigchild for 14625 exit=0
file1
file2
file3
got to here
second ls for /tmp/foo
file1
file2
file3

The program never exits, and as you see, the sigchild message only got printed on
the first exec