[mythtv-users] Mythfrontend on Android-database access

[Stephen Worthington]

On Mon, 16 May 2022 09:53:27 +0100, you wrote:

>On 16/05/2022 03:14, Stephen Worthington wrote:
>> On Sun, 15 May 2022 13:11:27 -0500, you wrote:
>> 
>>> By the way, a couple more data points; the mysql root user does not have
>>> a password.  Also, the mythfrontend password is still mythtv, not the
>>> generated one (y2i1MpJ8).  When migrating the old database to the new
>>> machine, it seems to use the stock 'mythtv' password, so I left it as-is
>>> (changed config.xml password).  Any other suggestions?
>>>
>>> Don
>> 
>> There is a big difference between
>> 
>> sudo mysql
>> 
>> and
>> 
>> mysql -u root -p
>> 
>> When mysql is run from root with no password, it has full permissions
>> for everything possible.  When it is run as user root with "-u root",
>> it only has permissions a specified in the grants for user "root".
>> 
>> When you migrate a database (or restore an old one), only the
>> mythconverg database tables are migrated or restored by
>> mythconverg_restore.pl.  Users and their grants are stored in the
>> "mysql" database tables, and are not touched, so you have to manually
>> set them up again.  They must match what you have in your config.xml
>> files in /etc/mythtv, /home/mythtv/.mythtv and /home/<frontend
>> user>/.mythtv.  When I move a database, I normally copy the old
>> config.xml files and re-create the old users and grants, but you can
>> choose to use the new config.xml settings too.  But you still need to
>> create the users and grants.
>> 
>Can I ask why the old users and grants are not migrated along with the database? After all, these 
>are essential metadata and having to (research and) re-input those commands introduces possibilities 
>for mistakes and errors.

My guess would be that it is way too difficult.  Access to the users
and grants requires MySQL/MariaDB permissions on the "mysql" database.
The mythconverg_backup.pl program would need to be run as root to do
that, or as a MySQL/MariaDB user with the special permissions
required.  And then which users need to be backed up and restored?
There would need to be options to allow the usernames to be specified
as there is no automated way of finding all the config.xml files you
are using and getting the usernames from them.  They can be on
different PCs and devices.  And the "create user" and "grant" commands
have been changing, so support would be needed for different versions
of MySQL and MariaDB doing things differently.  And in any case, there
is no way to extract the passwords from MySQL/MariaDB - the design of
the way they work explicitly prevents that.  So the passwords would
also need to be found in the config.xml files.

The names of the backup and restore programs (mythconverg_backup.pl
and mythconverg_restore.pl) also strongly suggest that they are only
going to work on the mythconverg database, not on data stored anywhere
else.