Re: Policy wrt mail lockfile (section 4.3)
>>>>> "Christian" == Christian Schwarz <firstname.lastname@example.org> writes:
Christian> This is buggy since it's not working over NFS. (I'm
Christian> running into problems every few days since I use
Christian> sendmail/procmail/pine over a NFS mounted
Christian> /var/spool/mail !)
Christian> That's the exact reason why I started this discussion
What happens? Can you describe the problem? Explain your setup in
more detail, please. I would like to know more about the problems
that are encountered with nfs.
Christian> There are also tools available, that do locking, for
Christian> example "lockfile" in the procmail package. However,
Christian> calling this program with "system" produces IMHO too
Christian> much unnecessary overhead and the source code of this
Christian> program is a bit to complicated to force all our
Christian> developers to implement this.
Unix is designed around peicing things together from small utility
programs, and fork/exec/wait probably doesn't really "cost" that
much... on the other hand, putting the lockfile stuff into a shared
library is more estheticly appealing.
Christian> IMHO, the code in "publib" looks very good. I suggest
Christian> that we extract the necessary files and put them
Christian> together in a new package, called "liblockfile" (or
Christian> similar). This package should install a shared library
Christian> "liblockfile.so" that contains a few necessary commands
Christian> to lock/unlock/test a file.
Solaris has a maillock library that is cloned in `qpopper'. A manual
page for Sun's maillock can easily be found on the web. I think that
qpopper's algorithm is superiour to the one in publib. Will you have
a look at it? Publib uses the return value from the stat call, which
you're not supposed to do. (I don't know why yet.)
Christian> In addition, we could create a new "lockfile" binary
Christian> (just as in procmail) that can be used by shell scripts
Christian> or other programs (via "system").
I guess we should mimic the maillock library, but add a more general
function for creating a lock for any file, not just mail spools. How
does DCE do it, I wonder? I found libuuid in the ext2fsprogs.
What's a lockd do? I will search for that today.
Christian> We'll also provide "modules" for Perl/Python/etc.
Can you use SWIG for that, once we make a .so?
Karl M. Hegbloom <email@example.com> finger or ytalk:
Portland, OR USA
Debian GNU 1.3 Linux 2.1.36 AMD K5 PR-133
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