Date: Mon, 17 Nov 2003 09:55:28 +0000
From: viro@parcelfarce.linux.theplanet.co.uk
To: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>, linux-kernel@vger.kernel.org
Subject: Re: seq_file and exporting dynamically allocated data
Message-ID: <20031117095528.GV24159@parcelfarce.linux.theplanet.co.uk>
References: <20031117090339.GC22764@holomorphy.com> <Pine.LNX.4.44.0311170937550.748-100000@einstein.homenet>
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On Mon, Nov 17, 2003 at 09:42:09AM +0000, Tigran Aivazian wrote:
> Here are two files: simple.c kernel module and user.c user test program.  
> If you (or anyone) believe it is possible to return more than a single
> page on a read(2) please change them accordingly and let me know.

> 	while (1) {
> 		len = read(fd, procs, MAXPROCS*PROCLEN);
> 		nproc = len/PROCLEN;

Broken userland code.  You expect read() to return a multiple of PROCLEN,
for one thing.  For another, you have (several lines below) a broken
loop termination logics.

EOF had been reached when read() returns 0.  Until then read() returns
an arbitrary amount of bytes between 1 and 'size' argument.  Since you
are using read(2) directly, use it correctly...
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