Messages in this thread | | | Date | Mon, 25 May 2009 17:46:30 -0600 | From | Robert Hancock <> | Subject | Re: chmod fails though it pretends to succeed |
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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
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