Pass extra mysqld flags to mysql_install_db

[yosifkit]

Same change as docker-library/mysql#358.

This will allow Docker for Windows/Mac users to add --innodb-flush-method=fsync and get MariaDB running with a datadir from the host.

Addresses #138. related to docker-library/percona#42

[tianon]

Just tested on Docker for Mac, and it's fine without this (so that fsync thing is probably only necessary for Windows). 👍

[jonhosmer]

This breaks when arguments like --init-connect="SOME COMMAND WITH A SPACE" are passed in. For example:

docker run -e MYSQL_DATABASE=test -e MYSQL_ROOT_PASSWORD=testpw -e MYSQL_USER=root mariadb:5.5 mysqld --init-connect='SET NAMES utf8' gives a Too many arguments error:

Initializing database
180524 16:26:09 [Note] /usr/sbin/mysqld (mysqld 5.5.60-MariaDB-1~wheezy) starting as process 162 ...
/usr/sbin/mysqld: Too many arguments (first extra is 'NAMES').
180524 16:26:09 [ERROR] Aborting
180524 16:26:09 [Note] /usr/sbin/mysqld: Shutdown complete
Installation of system tables failed!  Examine the logs in
/var/lib/mysql/ for more information.
...
Exited with code 1

The problem is actually with the mysql_install_db script which strips the quotes from the argument at line 159 (args="$args $arg").
It could easily be fixed by adding:

--init-connect=*) init-connect="\`parse_arg "$arg"\`" ;;

at line 150 of /usr/bin/mysql_install_db (in the parse_arguments() function, case "$arg" in statement), but that might be out of the scope of this Repository.
This change, however, causes that problem to surface when passing a valid mysqld arg to docker run mysqld command.

[tianon]

Ouch, that is unfortunate, but definitely an upstream bug.

[amq]

This is a rather critical issue, what can be done, or at least, what is the workaround?

[jonhosmer]

@amq What I did as a workaround was pin the docker image tag to mariadb:5.5.59.