Date: Sat, 8 Dec 2001 05:41:08 -0600 From: Alfred Perlstein <bright@mu.org> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: Dave Rufino <dr263@hermes.cam.ac.uk>, Terry Lambert <tlambert2@mindspring.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: statefulness in character device drivers Message-ID: <20011208054108.C92148@elvis.mu.org> In-Reply-To: <49036.1007811221@critter.freebsd.dk>; from phk@critter.freebsd.dk on Sat, Dec 08, 2001 at 12:33:41PM %2B0100 References: <Pine.SOL.4.33.0112081058220.29494-100000@orange.csi.cam.ac.uk> <49036.1007811221@critter.freebsd.dk>
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* Poul-Henning Kamp <phk@critter.freebsd.dk> [011208 05:35] wrote:
> In message <Pine.SOL.4.33.0112081058220.29494-100000@orange.csi.cam.ac.uk>, Dav
> e Rufino writes:
> >
> >
> >On Sat, 8 Dec 2001, Poul-Henning Kamp wrote:
> >
> >> >They are talking about "per-open", not "per-fd-instance" data,
> >> >which could easily exclude dup, dup2, and fcntl(f_DUPFD).
> >>
> >> If you don't include dup/dup2/fnctl in your accounting, you
> >> can only reliably tell "first open", "another open", "some close"
> >> and "final close". You an modulate this with the pid, but you
> >> still have no idea what is going on in any amount of detail.
> >
> >Speaking for myself, first open and final close would be all I need for
> >the nvidia driver - though i'm sure tracking dup/dup2/fcntl would be
> >preferable in the general case.
>
> first open/last close has been the UNIX way for decades...
Yes, but afaik without a way to differenciate between two
opens. Being able to notice whether a file is being operated
on via which open is the important part.
This would probably involve changing VOP_OPENs to pass a void **
that would be stored in the struct file that would be passed
to subsequent ioctl/read/write/close operations.
--
-Alfred Perlstein [alfred@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
http://www.morons.org/rants/gpl-harmful.php3
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