sink/TODO.md

Argument passing format

Argument parsing can be done with short -<chars...> and/or long --arg[{=, }<value>] (with or without value, = optional. Short arguments can be chained together: -abc is equal to -a -b -c. There can be multiple of these: -ie -O is equal to -i -e -O.

TODO Long arguments

• TODO User-set sink file path (e.g --path /path/to/sink) which overrides the default /dev/null.
• --env <file> - Read environment variables, line-by-line, from <file> in the format KEY=value and send that as the program's envp. Multiple of these can exist, they are concatenated. (example usage: LD_PRELOAD=malicious.so sink --env <(env | grep ^LD_PRELOAD) setuid-binary)
• --env=[<key>=<value>] - Add (or replace) <key>=<value> to/in envp. Multiple of these can exist. (example usage: sink --env=LD_PRELOAD=replace.so binary)

Short Arguments

• -i Replace stdin (default)

• -o Replace stdout (default)

• -e Replace stderr (default with feature REPLACE_STDERR)

• -I No replace stdin

• -O No replace stderr

• -E No replace stderr (default without feature REPLACE_STDERR)

• -p envp passthrough, including optional modifications. (see --env.) (default without feature NO_ENV)

• -P No envp passthrough, except optional modifications. (see --env.) (default with feature NO_ENV)

TODO Other options

• TODO Specific fd passthrough (probably long arg, could also possibly be short args for std{in,out,err} streams specifically)
• TOTO CLOEXEC control (short arg)
• TOTO add specific fds / open specific files (optionally also at specific fds) to passthrough (probably long arg)

Examples

Short args:

$ sink -ioe cat	# sink steam in,out,err
$ sink -iOE cat	# sink stream in. keep stream out and err
$ sink -O cat	# sink default streams, but keep out
$ sink -E cat	# sink default streams and err

TODO Long args:

Redundant examples

Short args:

$ sink -iI cat	# sink default streams and in (I comes after the redundant i)
$ sink -Ii cat	# sink default streams except in (i comes after the redundant I)

TODO Long args: