[TAG] pppd changing file permissions (Was Re: lpr works for user not root in Basiclinux 2.1)

[Ben Okopnik]

On Tue, Mar 27, 2007 at 08:54:41AM -0700, Kapil Hari Paranjape wrote:
> 
> The original problem was that "some" program was changing the permissions
> of the "dialout" device.
> 
> Now, *if* devices are removed and created (a la devfs/udevd) by some
> automated process then *that* could be the reason for the changing
> permissions.
> 
> Otherwise, it is some other program... :-(

I recall having this kind of problem a number of years ago, but I'm
afraid that my recollection of the fix is rather dim. If I *am*
remembering correctly, I ended up using "setserial".

I have a strong suspicion that, in this case, "pppd" itself is the
culprit. Running "strace" on the "pppd" process (with "-f" and "-s 4096"
options) and tracing the execution to see if it does anything silly with
the device might be helpful.
 
> Unfortunately, it seems as if too many aspects of BL are
> "non-standard" for most of us to be able to help in debugging this.
> This is especially so with regard to the "deconstruction" of the
> permissions system of Posix.[1]

[nod] On a "normal" system, I'd set the device to "chattr +i" and see
what process croaked (or complained in the log files.) On the B.A.D.
gadget that Sindi is using, it's anybody's guess.


-- 
* Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *