OESF Portables Forum

General Forums => General Discussion => Topic started by: gdog on August 16, 2004, 02:32:34 pm

Title: Oeration not permitted
Post by: gdog on August 16, 2004, 02:32:34 pm

Can't change ownership and/or permissions of files on my sd card, which is mounted rw (I can write files to it), as root (or zaurus). This is a new one on me. I'm used to being able to do most anything as root ;o)

Any help would be most appreciated!

Thanks,

gdog

Title: Oeration not permitted
Post by: iamasmith on August 16, 2004, 02:55:59 pm

I'm sure you are using a file system like ext2 and not fat on the SD card so I guess it couldn't be that you are using a file system that doesn't support owner attributes...

Title: Oeration not permitted
Post by: bluedevils on August 16, 2004, 02:56:07 pm

I have not had the problem, but I have seen a few thread headers that mention it.  A search should prove fruitful.

Title: Oeration not permitted
Post by: gdog on August 16, 2004, 03:40:13 pm

Quote

I'm sure you are using a file system like ext2 and not fat on the SD card so I guess it couldn't be that you are using a file system that doesn't support owner attributes...

Well I'm glad one of us is sure, lol

Actually I do have it mounted as vfat.... as I was trying to avoid problems later if in fact I wanted to use it as a Windows device. My bad. Guess I better move everything off and remake it.

Thanks for the tip!!!

gdog

Title: Oeration not permitted
Post by: iamasmith on August 16, 2004, 04:04:24 pm

OK, take care though, there are a few SD cards out there that don't 'take' to being reformatted.

If on the slightest chance you need read only with permissions then you may want to consider making a cramfs image, storing that on the card and mounting that.

Best of luck though.

Title: Oeration not permitted
Post by: gdog on August 16, 2004, 05:43:20 pm

I went ahead and remade the fs, then changed my fstab changes and it worked like a charm. Thanks for the advice and the warnings.

Regards,

gdog

Title: Oeration not permitted
Post by: gdog on August 16, 2004, 05:53:36 pm

Something that is wierd though, is that my CF card is a vfat fs and I can change permissions on the files on it....

Title: Oeration not permitted
Post by: iamasmith on August 17, 2004, 05:17:24 am

OK, what you can do and can't do with FAT/VFAT WRT:Ownership and permissions

Owner/Group display is controlled by flags on the mount options and effect the whole mounted volume so regardless of what you chown/chgrp to if you check the file again you will probably find it's still root access. The g (group) and o (other) mask may also be set in the fstab if you really want (see man pages for this).

When you set permissions you can effect the x bit and the w bit, as the attributes entry in fat allows limited storage for rights (including read only) - x is stored in... don't know, probably the 'archive' bit on fat.

Notice though that when you change perms you can only change u+perm and that the g+perm options don't do anything. Notice also that setting u+perm changes g+perm and o+perm. This is becasue fat doesn't provide storage for multiple permission sets and has nothing like an ACL.

Regards,

Andy