Re: saned - Problem found

becka@rz.uni-duesseldorf.de
Thu, 8 Oct 1998 16:46:41 +0200 (MET DST)

Hi !

[I haven't looked closely at your original mail, so my ideas might be
a bit vague ... ah - it's included below ... o.k.]

> It is a permission problem.
> Where I had user.group of nobody.nobody, I just did 'root.root' and it all
> started working just fine!
> Yes I know that using root is a bad idea, but it is great for trouble
> shooting.
>
> Now I looked at permission in /usr/local/sbin /usr/local/bin
> /usr/local/lib/ /usr/local/lib/sane /usr/local/etc/sane.d
> and all permessions look ok to me.

And the directories in between look o.k., too ?

> Did I miss some place? Is there some file that needs unusual permissions?

Maybe the device node of the hardware you want to access ? I.e. saned comes
up fine, but can't access the scanner ?

> What is the best way to trouble shoot a permission problem?

Generally (on Linux at least) strace is your friend. It will track a program
while it is executing.

So make a file /sbin/mysaned that basically holds:

#!/bin/bash
strace -f /sbin/saned 2>/tmp/saned.calllog

This should give you information about all saned (and eventual childs [-f])
does. It should especially show permission problems, as you will find -EPERM
or -EACCESS somewhere.

> > on 'laptop' ... on laptop I get nothing, just a new prompt, on home, in
> > the messages log I get:
> > Oct 8 09:39:08 home saned[331]: access by root@laptop accepted
> > Oct 8 09:39:08 home saned[331]: exiting
> > So, saned is running, the laptop does talk to it on home, but it does not
> > see any scanner devices, why?

Does the nobody.nobody user have access to the hardware ?

> > Recall that if I comment out the lines in inetd.conf and services, and run
> > saned from the command line with '-d', then the laptop does see the
> > scanner, and can even use it.

I suppose this is due to extra permissions when running saned "by hand".

CU,Andy

-- 
Andreas Beck              |  Email :  <Andreas.Beck@ggi-project.org>

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