From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <ee9e417a0607310737q44f579d9r59238627fb8a4326@mail.gmail.com>
Date: Mon, 31 Jul 2006 07:37:35 -0700
From: "Russ Cox" <rsc@swtch.com>
To: "Fans of the OS Plan 9 from Bell Labs" <9fans@cse.psu.edu>
Subject: Re: [9fans] group permission
In-Reply-To: <69081255-C87C-41C0-AA0A-3091DA3D8C9C@ar.aichi-u.ac.jp>
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References: <91D038E8-828E-451C-A069-265FF382D7D5@ar.aichi-u.ac.jp>
	<ee9e417a0607301239s1c6bd879x582c3dccf44f5a52@mail.gmail.com>
	<69081255-C87C-41C0-AA0A-3091DA3D8C9C@ar.aichi-u.ac.jp>
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> Russ's solution solves most popular case that arises in human group
> working.
> However allowing chgrp without editing /adm/users will solve
> different problem.
> Suppose bob is a teacher and he is teaching something to alice and
> carol.
> Alice want to show her files to only bob, and carol also want to show
> her files only to bob.
> How to do that ?
> Creating new group does not answer the purpose.
> The only solution of current Plan 9 is
>         chgrp bob ...
> by host owner.

There is another solution.

Bob can create a directory, say /bob/submit,
and make it group bob and mode 777.
Then alice and carol can each run
    mkdir /bob/submit/$user
    chmod 770 /bob/submit/$user
and put their files in that new directory,
which is owned by them but has group bob.

Russ