Old description

See also archive.org version of Apache on lingering

This is a tool to, basically, listen on a socket and call a script to serve the request.

It can do connects, too, or connect two programs with a socketpair to communicate with each other.

The interesting part here is, that it lingers on the socket before the connection is closed, such that the other (receiving) side has enough time to read all data from the socket. Without this, some last data might get lost.

For a more versatile program see socat. However it is not easy to use. (socat lacks transparent proxy support).

git clone https://github.com/hilbix/socklinger.git
cd socklinger
git submodule update --init
make
sudo make install

socklinger -h

socklinger socket command

socklinger [options] socket command args..

• Option -s to run command only a single time if -n0 (default) is used.

• Option -n-X to increase the number of parallel running commands to X

• Option -nX to prefork, that is socklinger forks before the accept().

• killall -1 socklinger gracefully shuts down socklinger

• Environment in the forked program:

  • SOCKLINGER_NR internal number of the connection
  • SOCKLINGER_PEER peer name (IP:port)
  • SOCKLINGER_SOCK socket name from commandline
  • SOCKLINGER_MAX maximum parallel processes
  • SOCKLINGER_COUNT count of processes forked at time when this spawned
  • SOCKLINGER_PID PID of socklinger parent
  • SOCKLINGER_NOW timestamp as reference

(This README currently is terribly incomplete.)