[linux-lvm] Writing forward compatible applications using /proc
Terje Kvernes
terjekv at math.uio.no
Mon Aug 13 09:10:43 UTC 2001
Jason Tackaberry <tack at linux.com> writes:
> I have some ideas for a comprehensive GUI disk administration tool,
> and I am first thinking about some of the issues I'll face regarding
> interfacing with controllers, disks, partitions, md, and LVM.
cool. I've written a perl module to interface LVM via /proc. if
you're interested I'll repost some of the code here. it's a backend,
totally seperate from any representation of the data.
> I am curious if it's a silly idea to write an application that
> relies on the data in /proc?
not really. some of the tools need special permissions to be run,
and I _might_ want to have a quick peek at my LVM status without
being root. besides, it's a lot cleaner (IMHO) than doing piping
things to a process and catching the output, like the suggestion is
atm.
> I don't mind having to release a new update to be compatible with a
> new format in /proc every once and a while, but if it's constantly a
> moving target I may want to look at alternatives.
you'll have to keep somethings in mind, before 0.9.1 beta 8 the PV's
listed in /proc only had their basename listed. using devfs this
could break badly, as you'd get easily get two identical
identifiers. so you'd still have to check what data you're getting
and see what you can, or more importantly can't, do.
> I also have the same question with LVM related tools. Is it sane to
> try to wrap a GUI around lvm tools or is there some API approach
> that would be better?
I've wrapped the tools to do the dirtywork. as in, I use create a
lvextend-command when someone does a "$lv->size('+1G')".
--
Terje
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