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To: Terry Lambert <tlambert2@mindspring.com>
In-Reply-To: Your message of "Sun, 20 Jul 2003 05:49:02 PDT."
             <3F1A8FBE.E0ACB134@mindspring.com> 
Date: Sun, 20 Jul 2003 16:00:58 +0100
From: Ian Dowse <iedowse@maths.tcd.ie>
Message-ID: <200307201601.aa07561@salmon.maths.tcd.ie>
cc: arch@freebsd.org
Subject: Re: *statfs exposure of file system IDs to non-root users 
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In message <3F1A8FBE.E0ACB134@mindspring.com>, Terry Lambert writes:
>Ian Dowse wrote:
>> In changing umount(8) to use statfs(2), I just noticed that the
>> various *statfs calls hide the filesystem IDs from non-root users:

>The real question is "Why do you need this information?".
>
>If you can answer that, we can probably tell you a different
>approach to solving your problem.

See previous posts here on the subject of unmounting by filesystem
ID. The filesystem ID is a way of unambiguously specifying which
file system is to be unmounted, whereas the mountpoint or device
node may not be unique. The umount utility now passes a filesystem
ID to unmount(2), which works fine when run by root and when umount
is extracting an entry from the list obtained from getfsstat(2),
but it doesn't work as a normal user when the ID comes from statfs(2).

Ian