accessing centos5.2 partition from ubuntu : "bash: cd: ckgan: Permission denied"

centguy · 02-21-2009, 09:44 AM

I have installed centos5.2 on /dev/sda3 but I have also installed ubuntu on the same physical machine on a different partition.

I logon to ubuntu and
I tried to "cd /sda3/home/ckgan" but I get
"bash: cd: /sda3/home/ckgan: Permission denied"

I could still access /sda3/home/ckgan using the root account, in fact:

root@ubuntu804-32-dell:/sda3/home# ls -dl ckgan
drwx------ 46 500 500 4096 2009-02-21 13:49 ckgan

I vaguely remember I don't have such problem when I login to centos5.2.

What should I do ?

Thanks!

centguy · 02-21-2009, 10:05 AM

Another observation: from centos5.2, I can access Fedora 10 partition or
ubuntu partition.

sda7 is the F10 partition:

[ckgan@centos52-64-dell home]$ ls -ld /sda7/home/ckgan
drwx------ 27 ckgan ckgan 4096 Feb 8 00:01 /sda7/home/ckgan

sda8 is the ubuntu partition:

[ckgan@centos52-64-dell home]$ ls -ld /sda8/home/ckgan
drwxr-xr-x 36 1000 1000 4096 Feb 21 23:55 /sda8/home/ckgan

So I don't understand something very basic I think...

centguy · 02-22-2009, 12:11 AM

After chown files to ckgan, i have "solved" the problem.

ckgan@ubuntu804-32-dell:~$ ls -ld /sda3/home/ckgan
drwx------ 46 ckgan ckgan 4096 2009-02-22 14:02 /sda3/home/ckgan

Someone may tell me why it was

root@ubuntu804-32-dell:/sda3/home# ls -dl ckgan
drwx------ 46 500 500 4096 2009-02-21 13:49 ckgan

Why that "500"?! Oh well, I am venturing into the dark sides of linux..

centguy · 02-22-2009, 12:32 AM

Another surprise awaiting, when I boot up centos5.2 and try to login as ckgan,
an error message shows up:

"User's $HOME/.dmrc file is being ignored. This prevents the defaults session and language from being saved. File should be owned by user and have 644 permissions. User $HOME directory must be owned by user and not
writable by other users."

A "ls -dl ckgan" shows that
drwx------- 46 1000 1000 Feb 22 14:33 ckgan

So I have chown ckgan back in Centos in order to login.

What is going here ?

centguy · 02-23-2009, 08:04 PM

I guess I can read about the huge manuals on mount, ls -l, chgrp, uid, but is anyone there could provide a simple solution? I guess I am not the first to want to share partitions across different linux systems. Thanks!

centguy · 02-24-2009, 12:18 AM

finally i asked someone who knows linux. Basically the uid for ckgan on centos5.2 and f10 are the same, which is 500. For ubuntu, the uid happens to be 1000, but then the default mode is to allow others to read and execute. finally i understood the issues of uid and gid. i hope my experience will be useful to others...