From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
From: Aharon Robbins <arnold@skeeve.com>
Message-ID: <newscache$xkckch$o34$1@lnews.actcom.co.il>
References: <200303301036.h2UAaEFZ031353@localhost.localdomain>, <091f807138892efebadcbbde9ac80bd7@plan9.bell-labs.com>
Subject: Re: [9fans] size on /proc files?
Date: Mon, 31 Mar 2003 09:08:38 +0000
Topicbox-Message-UUID: 87ad377e-eacb-11e9-9e20-41e7f4b1d025

David,

I don't know that I advocate actually changing any OS code.  I was just
curious what Plan 9 does.  It came up because someone did

	gawk '/devfs/ { print }' /proc/filesystems

and that failed.  My changed code would now work as-is under Plan 9, so I'll
leave it at that.  I may even remove the test, and just rely exclusively
on a zero return from read() to indicate EOF.  (rob would probably tell me
that's what I should have done in the first place. I think I even tried
that and it didn't work, which indicates that I need to rethink the code
some more.)

Thanks,

Arnold

P.S., just out of curiousity, can someone feeling charitable try to configure
and compile gawk under Plan 9? I'm curious if it would work, at least under
the APE. ftp://ftp.gnu.org/gnu/gawk/gawk-3.1.2.tar.gz. `configure --disable-nls'
is probably better than plain configure. If it fails, don't feel obligated
to submit patches or sink a lot of time into it. Thanks.

In article <091f807138892efebadcbbde9ac80bd7@plan9.bell-labs.com>,
David Presotto <9fans@cse.psu.edu> wrote:
>-=-=-=-=-=-
>
>We're equally stupid, though we could to a bit better.  The register
>files and status files show the real lengths but the text and mem
>file don't.  I'll see what I can do.
>-=-=-=-=-=-
>
>Just out of curiousity, what does ls -l on special files in /proc report?
>On linux, e.g., /proc/filesystems shows up as a regular file, but of size
>zero.  Yet when you cat it you get information.
>
>This behavior broke the current gawk, where I'd rewritten the get_a_record
>routines; they had a check:
>
>	if (S_ISREG(sbuf.st_mode) && total > sbuf.st_size)
>		flag |= AT_EOF;
>
>I had to change this to
>
>	if (S_ISREG(sbuf.st_mode) && sbuf.st_size > 0
>	    && total > sbuf.st_size) ....
>
>I am annoyed at the Linux behavior, but understand that the contents
>of these "files" can change dynamically, making the reporting of a size
>for stat difficult or impossible.
>
>So, I was just curious how Plan 9 handles it.
>
>Thanks,
>
>Arnold Robbins
>-=-=-=-=-=-


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