Some libraries, like [proper-lockfile](https://www.npmjs.com/package/proper-lockfile)
use directories instead of files for locking. This PR allows the supervisor to be able to
work with those types of locks when lock override is requested.
Closes: #1978
Change-type: patch
When disposing of resources which include Supervisor-created lockfiles,
only dispose of lockfiles for the specified user application.
Signed-off-by: Christina Wang <christina@balena.io>
The linked issue describes the Supervisor not cleaning up locks it creates due
to crashing at just the wrong time. After internal discussion we decided to
differentiate Supervisor-created lockfiles from user-created lockfiles by using
the `nobody` UID (65534) for Supervisor-created lockfiles.
As the existing NPM lockfile lib does not allow creating lockfiles atomically
with different UIDs, we move to using the lockfile binary, which is part of the
procmail package. To allow nonroot users to write to lock directories, permissions
are changed to allow write access by nonroot users.
See: https://www.flowdock.com/app/rulemotion/r-resinos/threads/gWMgK5hmR26TzWGHux62NpgJtVl
Change-type: minor
Closes: #1758
Signed-off-by: Christina Wang <christina@balena.io>
