lkml.org 
[lkml]   [2009]   [May]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: chmod fails though it pretends to succeed
Christoph Pleger wrote:
> Hello,
>
> I have a strange problem here with a C program that calls chmod.
>
> The C program is a PAM module called pam-devperm. The purpose of this
> module is to set appropriate device ownerships and permissions when a
> user logs in. But the module does not work as expected on my Ubuntu
> 9.04 system. When a user logs in the first time after system boot, only
> the device ownerships are changed, the permissions are not. When the
> user logs out and in again, permissions are changed, too.
>
> I added some lines of code to the the source of of pam-devperm so that
> it produces more debug output when changing the properties of /dev/dsp.
> The debug output showed me that chmod has been called to set the
> permissions of /dev/dsp to 0600 and that chmod returned 0, which means
> success. In spite of that, device permissions remain at 660.
>
> Now I have two questions:
>
> 1. What can be the reason for chmod to return a value of 0 though
> device permissions have not been changed?
>
> 2. What can be the reason why this chmod fails on the first login of a
> user, but succeeds on further logins?

Are you sure that some other process is not changing the device
permissions also?

>
> Regards
> Christoph



\
 
 \ /
  Last update: 2009-05-26 01:49    [W:0.042 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site