Commit cf0dbc906 recently added the ability for setuid binaries to be
located in /usr/Tests. This should really now be read only to mitigate
the potential misuse of any of the setuid binaries.
To ensure everything works as expected, a unit test was added with
multiple scenarios.
This binary has to have the SetUID flag, and we also bind-mount the
/usr/Tests directory to allow running of SetUID binaries.
Since it is owned by root anyway, there is no need for 'additional security' to prevent
modification of that directory. This makes it easier to quickly export files from
Serenity. Fixes#5152.
The DevFS along with DevPtsFS give a complete solution for populating
device nodes in /dev. The main purpose of DevFS is to eliminate the
need of device nodes generation when building the system.
Later on, DevFS will assist with exposing disk partition nodes.
To keep track of ongoing terminal sessions, we now have a sort-of
traditional /var/run/utmp file, like other Unix systems.
Unlike other Unix systems however, ours is of course JSON. :^)
The /bin/utmpupdate program is used to update the file, which is
not writable by regular user accounts. This helper program is
set-GID "utmp".
