MTP transfers write files to the home folder of the user.
If no GID and UID are specified, uMTP-responder will use the GID/UID
under which it is running at the time of the file transfer.
This causes users to not be able to access the files on the device after transfering.
This patch adds a systemd generator that:
1) reads /etc/default_user, and appends config to
/etc/umtprd/umtprd.conf to set the MTP default user/group. If this
file doesn't exist, 10000:10000 is the fallback uid:gid.
2) installs this config to /run/umtprd/umptrd.conf
3) adds a unit override to /run for umtprd.service that runs the daemon
with this modified config
The generator is used instead of hardcoding a uid and gid in umtprd.conf
so that this can support immutable installs or situations where the
default UID/GID is not 10000.
Co-authored-by: Dylan Van Assche <dylan@postmarketos.org>
Signed-off-by: Clayton Craft <craftyguy@postmarketos.org>
Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/7658>
