[Techtalk] wvdial, pppd, and permissions insanity

[Almut Behrens]

On Fri, Oct 14, 2005 at 01:19:12AM -0700, Carla Schroder wrote:
> 
> Nothing I do gets ordinary unprivileged users out of their homedirs- not suid 
> on pppd, nor stuffing everone into the same groups- nothing. I get the same 
> error: 'Cannot open device foo. Device or resource busy.'
> 
> Yes, I'm sure I have the correct serial port- it works for the root user.
> 
> All brilliant notions welcome.

no brilliant notions... just a thought:  to me it seems the problem has
to do with obtaining a lock on the device (instead of being related to
file permissions of the device itself...).

Maybe you have a stale lockfile (owned by root) or something like
that...  You might want to check

* whether you have any lock files like "/var/lock/LCK..ttyS1" -- if so
  remove them.

* whether the directory /var/lock has proper permissions -- should be
  the same as those of /tmp, i.e.

$ ls -ld /var/lock 
drwxrwxrwt    3 root     root         4096 14. Okt 07:37 /var/lock
       ^^^
so ordinary users are allowed to create files in there.

The above error message is printed by wvdial (not pppd).  So, if all
else fails, I would just strace this program to find out what exactly
it's trying to do immediately before printing that message, and why
that is failing...

Good luck,
Almut