gid as bit mask

[utzoo!decvax!ucbvax!unix-wizards]

>From Hedberg at SUMEX-AIM Thu Oct 15 21:09:03 1981
I have an immediate need for allowing files to be written by more than
one group, and for people to be members of more than one group at a time.
I heard a 'rumor' Berkeley has done something along this line, but haven't
seen it and can't wait.  I was thinking of simply defining the group id
field of both users and files to be a bit mask, and changing an '==' to
a '&' in access() in the kernel.  Thus if any of your group bits matched
the file's bits, you win.  The group "numbers" would have to be assigned
geometrically, and would certainly look ugly in decimal.  Does anyone
know of some hidden dependency requiring gids to be small integers?  Can
anyone think of a better quick and dirty fix?

Erik Hedberg
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