libmutton/wiki/developers.md

Developer Guide (for third-party libmutton-based clients)

Important Notice: libmutton is in early development and is currently a moving target to develop off of. Feel free to jump in early, but greater change stability will be met with release v1.0.0. Check here for planned breaking changes.

libmutton was designed to be usable as a library for building other compatible password managers off of. MUTN is the official reference CLI password manager, however libmutton can be implemented in many other unique ways.

All functionality in the core and sync packages are designed to be used in other implementations.

If any functionality in these two packages proves to be difficult to implement in a third-party client, please open an issue so that it can be addressed.

Build Tags

Custom build tags can (and sometimes must) be used to achieve desired results.

These are as follows:

• interactive: If making an interactive interface (GUI/TUI/interactive CLI), you probably need to use this build tag. Without it, your entire program will exit after any given operation is completed. This behavior is only desired for non-interactive CLI implementations, such as MUTN. Currently, most errors will result in the program exiting even with this build tag. Specific types of errors (such as config parsing/SSH dialing errors) have been made exempt from this behavior.
• wsl: Allows creating a Linux binary that can interact with the Windows clipboard (for WSL)
• termux: Allows creating an Android binary that can interact with the Termux clipboard (for Android)

Required Global Variable Manipulation

libmutton provides a PassphraseInputFunction global variable that all clients must set to support passphrase-protected SSH identity files. This approach allows for different types of clients (CLI, GUI, TUI) to prompt for the passphrase in the most appropriate way.

Required Arguments

• clipclear: Should be accepted by all non-interactive CLI libmutton implementations (not required for interactive GUI/TUI implementations). In order to clear the clipboard on a timer, non-interactive libmutton-based password managers call another instance of their executable with the clipclear argument (e.g. mutn clipclear) with the intended clipboard contents provided via STDIN. If after 30 seconds the clipboard contents have not changed, they are cleared. Please accept a clipclear argument that calls core.ClipClearArgument().
• startrcwd: Should be accepted by all libmutton implementations making use of the RCW daemon to cache passphrases. Please accept a startrcwd argument that calls core.RCWDArgument().

Configuration

libmutton-based password manager clients should all share the same INI configuration file.

On UNIX-like systems, this is located at ~/.config/libmutton/libmutton.ini. On Windows, it is located at ~\AppData\Local\libmutton\config\libmutton.ini.

Base libmutton.ini Layout

The current base layout of libmutton.ini will change leading up to release v1.0.0. As of right now, the specification is as follows:

[LIBMUTTON]
sshUser = <remote user>
sshIP = <remote ip>
sshPort = <remote ssh port>
sshKey = <ssh private key identity file path>
sshKeyProtected = <true/false>
sshEntryRoot = <remote entry root>
sshIsWindows = <true/false>

If creating a third-party client that requires extra configuration to be stored, please use the same file and create a new INI section for your application-specific configuration, e.g.:

[THIRD-PARTY-CLIENT-NAME]
configKey = <value>

This ensures that a user can use multiple client applications with the same configuration while avoiding conflicts.