mailing list archives
From: hzoli () FRONTIERNET NET (Zoltan Hidvegi)
Date: Tue, 29 Jul 1997 01:16:42 -0400
Ariel Biener wrote:
/sbin/request-route is a script. So, the script can be fixed to check for
the lock file, or whatever other security check are needed. No need to
just go and remove before finding a suitable solution.
A simple solution would be to add a:
set -o noclobber
In the script, right here:
sleep 60 &
---> set -o noclobber
echo $sleepid > $LOCK
Unfortunately this is still not enough. The problem is that many (if not
most) shells do not implement noclobber in a race-free way, but even if
they do, noclobber still allows writing to device special files, so a
symlink to /dev/hda will be followed by the shell destroying your master
boot record. As far as I know, there is no portable way to safely create
lock files in a world-writable directory from a bourne-shell script.
If the script runs as root (as it is the case with request-route), it is
enough to put the lockfile in a directory writable only by root. Debian
uses /var/run for the request-route lockfile.
Re: CPSR 7: IRIX WWW Server Lamont Granquist (Jul 24)