oss-security - RE: [patch] proc.5: tell how to parse /proc/*/stat correctly

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Message-ID: <fe260c38cf7e416288449691bb9cb5dd@AcuMS.aculab.com>
Date: Sat, 31 Dec 2022 16:31:30 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Shawn Webb' <shawn.webb@...denedbsd.org>,
	"oss-security@...ts.openwall.com" <oss-security@...ts.openwall.com>
CC: Alejandro Colomar <alx.manpages@...il.com>, Michael Kerrisk
	<mtk.manpages@...il.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-man@...r.kernel.org"
	<linux-man@...r.kernel.org>
Subject: RE: [patch] proc.5: tell how to parse /proc/*/stat
 correctly

From: Shawn Webb
> Sent: 28 December 2022 15:25
> 
> On Tue, Dec 27, 2022 at 04:44:49PM -0800, Lyndon Nerenberg (VE7TFX/VE6BBM) wrote:
> > Dominique Martinet writes:
> >
> > > But, really, I just don't see how this can practically be said to be parsable...
> >
> > In its current form it never will be.  The solution is to place
> > this variable-length field last.  Then you can "cut -d ' ' -f 51-"
> > to get the command+args part (assuming I counted all those fields
> > correctly ...)
> >
> > Of course, this breaks backwards compatability.
> 
> It would also break forwards compatibility in the case new fields
> needed to be added.
> 
> The only solution would be a libxo-style feature wherein a
> machine-parseable format is exposed by virtue of a file extension.
> 
> Examples:
> 
> 1. /proc/pid/stats.json
> 2. /proc/pid/stats.xml
> 3. /proc/pid/stats.yaml_shouldnt_be_a_thing

None of those are of any real use if you are trying to parse the
data in something like a shell script.
Multiple lines formatted as "tag:value" are probably the best bet.
Provided something sane is done with embedded \n (and maybe \r).

	David

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