How can I kill child processes with start-stop-daemon?

Question

I'm writing a simple web server using nc and bash. It looks like this:

#!/bin/bash
rm -f /var/run/streamman/out
mkfifo /var/run/streamman/out
trap "rm -f /var/run/streamman/out" EXIT

while true
do
    cat /var/run/streamman/out | nc -l 8080 > >( # parse the netcat output, to build the answer redirected to the pipe "out".
    while read line
    do
      line=$(echo "$line" | tr -d '[\r\n]')
      if echo "$line" | grep -qE '^GET /\?action' # if line starts with "GET /"
      then
        action=$(echo "$line" | cut -d '=' -f2 | cut -d ' ' -f1 | cut -d '&' -f1) # extract the request
        query_str=$(echo "$line" | cut -d '&' -f 2-)
        args=$(query_string_to_args $query_str)

        fn_exists $action && eval ${action} ${args} || echo "No route for $action"  
      elif [ "x$line" = x ] # empty line / end of request
      then
            header=$(cat /var/www/header.html)
            footer=$(cat /var/www/footer.html)
            echo  "$header somecontent $footer" > /var/run/streamman/out
      fi
    done
  )
done

There are some extra functions in there but I left them out for brevity.

I start it as a daemon using the following init script:

#!/bin/bash
user=streamman
name=streamman-httpd
prog=/usr/sbin/streamman-httpd

case $1 in
    start)
        start-stop-daemon --start --user $user --chuid $user --background --umask 0000 --exec $prog > /var/log/streamman/streamman.log 2>&1
        ;;
    stop)
        /sbin/start-stop-daemon --stop --user "$user" --name "$name" --retry=TERM/5/KILL/1
        ;;
    restart)
        ;;
    *)
        ;;
esac

Here is the output of ps afx after starting the service:

3023 ?        S      0:00 /bin/bash /usr/sbin/streamman-httpd
3065 ?        S      0:00  \_ nc -l 8080
3066 ?        S      0:00      \_ /bin/bash /usr/sbin/streamman-httpd

As you can see, a child process has started up for some reason. I think it's to do with the way I use nc and the named pipe.

Now when I try to stop the service I get this:

Program streamman-httpd, 1 process(es), refused to die.

And the output of ps afx:

3065 ?        S      0:00 nc -l 8080
3066 ?        Z      0:00  \_ [streamman-httpd] <defunct>

For some reason the child process won't die.

I've tried using pid files, but I can't get my server script to output the child's pid to a file.

How can I make it kill both processes?

Answer 1

I think the primary cause is "exec" call in your "start" section. Could you add to trap "rm -f /var/run/streamman/out" EXIT string something like:

; ps ax | kill `awk '$5 ~ /nc -l 8080/ {print $1}`

I understand this is a dirty workaround...