Hi folks! I'm just working on a new Policy manual and discovered that we don't have a (working) locking policy right now.
AFAIK, this issue came up two times here on debian-devel (about end of Jan 97 and beginning Feb 97) and was about email folder locking and locking of /etc/passwd. AFAIK, the only way to lock a file (even reliable over NFS) is to create another file with a unique filename, e.g. foo.lock-ipaddress-processid, and create a link say to foo.lock. The "link" function is atomic per definition, even via NFS and will fail if the file already exists. Is this correct? I suggest that we 1) document the right way of locking (TM) in our Policy Manual, 2) force _all_ programs touching mail folders, /etc/passwd and alike to support our way of locking 3) build a "libdebian" package with a shared library that contains a few functions to lock, unlock, test a file (each program that needs to lock a file should be linked against this library and call our functions) 4) provide examples for other languages than C (for example Perl) I just had a look at the old discussion and discovered that Miquel van Smoorenburg ([EMAIL PROTECTED]) has already written such a library. Perhaps we can use his (and adopt it if necessary). If I remember right someone else posted a Perl example for right file locking--but I can't find it. Anyways, it would be nice if someone more competent in these things could provide me a section that I could include in the policy manual. As always, any comments are appreciated. Thanks, Chris -- Christian Schwarz Do you know [EMAIL PROTECTED], [EMAIL PROTECTED], Debian GNU/Linux? [EMAIL PROTECTED], [EMAIL PROTECTED] Visit PGP-fp: 8F 61 EB 6D CF 23 CA D7 34 05 14 5C C8 DC 22 BA http://www.debian.org http://fatman.mathematik.tu-muenchen.de/~schwarz/ -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word "unsubscribe" to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED] .