motd

motd is a crate for printing the current MOTD (message of the day) on linux. Most of the logic lives in the motd crate, and the dump-motd tool is a thin wrapper which provides a command line interface for the crate.

Dependencies

You must install libpam headers to build this crate. On debian based systems you can do so with

sudo apt-get install libpam0g-dev

Features

There are two modes of operation for the motd crate. By default, it will load and call into the pam_motd.so file used by the pam stack, but you can instead use a pure rust reimplementation of the logic found in pam_motd.so if you want. The downside of the pure rust implementation is that it no longer uses the same source-of-truth logic to resolve the motd, though this is likely not a huge deal because pam_motd is fairly stable. The pure rust implementation has the advantages that it uses zero unsafe code, does not require a (sometimes slow) directory walk to locate pam_motd.so the first time it is run, and requires many fewer dependencies.

The feature for calling pam_motd.so directly is socall, and it is enabled by default. To use the pure rust implementation, disable default features. This will change the signature of a few functions.