Re: [9fans] the meaning of group

["roger peppe" <rogpeppe@gmail.com>]

> the problem is that this information needs to be updated across all cpu servers
> more often than everything is rebooted.

it seems to me that if this was a real requirement, and you wish group
coordination across several machines, that you could add a kernel
service, say #G, which would provide a file, say "groupquery", that
some trusted process could read, in the style of factotum's needkey,
to answer group requests for the kernel.  inside the kernel, perhaps
you'd provide call "ingroup(user, group)" to query whether a particular
user was a member of a particular group - it would block until the
request was answered, or return false if no process has opened the
file.

to speed things up, you could implement a simple leasing system which
would allow ingroup() to cache answers for a while rather than going
to user space each time.

once you've got this primitive, you could link it to whatever you
liked, for instance a fileserver instance, or a protocol mediated by
factotum.