Introduction

Sockproc daemon is a simple server for executing shell commands or processes. It can be useful in the situations, where a typical system call to launch a child process and wait for its completion is unacceptable, due to its blocking nature. Instead, a socket can be opened to sockproc, a command written to it, and then once child process completes, its exit code, output stream data and error stream data can be read back from the socket.

Example

Launch sockproc on a UNIX domain socket:

$ ./sockproc /tmp/shell.sock

Connect to socket and type in a command line to execute, followed by a line that contains the number 0:

$ telnet /tmp/shell.sock
Trying /tmp/shell.sock...
Connected to (null).
Escape character is '^]'.
find /usr/local/include | grep lua
0
status:0
109
/usr/local/include/lua.h
/usr/local/include/lua.hpp
/usr/local/include/luaconf.h
/usr/local/include/lualib.h
0
Connection closed by foreign host.

Execute a bad command:

$ telnet /tmp/shell.sock
Trying /tmp/shell.sock...
Connected to (null).
Escape character is '^]'.
foobar
0
status:32512
0
37
/bin/bash: foobar: command not found
Connection closed by foreign host.

Wire protocol

The protocol is very simple, similar somewhat to HTTP:

Request format:

<command-line>\r\n
<stdin-byte-count>\r\n
<stdin-data>

Response format:

status:<process-exit-code>\r\n
<stdout-byte-count>\r\n
<stdout-data>
<stderr-byte-count>\r\n
<stderr-data>

License

The MIT License (MIT)