Groups and permissions

[werdigo49]

Wrestling with mysql (thread elsewhere), I find I cannot view /var/lib/mysql as user. Viewing it with sudo shows that all files have owner and group as "mysql." Yet in System Settings/User Manager, I made sure that the list of my Secondary Groups includes "mysql".

Shouldn't this allow me to view and change permissions of files owned by "mysql"?

I'm no "new guy" but feel like one frequently. This has got to be a pretty basic question, fundamentally about the meaning of a user's membership in various groups.

Oops, forgot Snowhog's request. Lucid 10.04.1, KDE 4.5.1. I don't imagine the other stuff (CPU, video card, etc.) is relevant.

[GreyGeek]

Re: Groups and permissions

http://computingtech.blogspot.com/20...tu-groups.html

You can check to see what groups the system has you in by using
groups youraccountname
and what members are in a specific group by using
members groupname

(You may have to "sudo apt-get install members" in order to use it.

[Ole Juul]

Re: Groups and permissions

Interesting. On my 8.04 LAMP server, I can view all the files in /var/lib/mysql. However, I installed mysql in /var/www/mysql/ and, as a regular user, I can see all those files as well. They are indeed of group and ownership "mysql", but I have no such group set up. I do however, belong to "www" as does root.

Could it be something in your /etc/apparmor.d/usr.sbin.mysqld file? It should have a couple of lines similar to the following:

 /var/lib/mysql/ r,
 /var/lib/mysql/** rwk,

If the "r" is not there, then you can't read.

[werdigo49]

Re: Groups and permissions

Thanks, GreyGeek and Ole Juul! "groups john" shows "mysql" among them, and "members mysql" (after installing it... thanks again!) shows "mysql john". An examination of /etc/apparmor.d/usr.sbin.mysqld shows exactly what you have, Juul: r and rwk.

BTW, with Dolphin open and /var/lib/mysql selected (an empty pane with a red "cannot enter /var/lib/mysql" at the bottom), when I used Konsole to change ownership of its files to "john" the file list instantly appeared in the Dolphin pane. Wonder what's going on with "mysql"!

EDIT: After that experiment, I changed the ownership back to "mysql." Dolphin is NOW allowing me (user) to access directories (such as /var/lib/mysql) owned and grouped by "mysql." Guess the mysterious gremlins inside this box changed their minds... why the change is a puzzle to me, but it's what I wanted, so I guess it's OK.