Re: Staging: speakup - syle fix permissions to octal

From: Julia Lawall <julia.lawall@lip6.fr>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Julia Lawall <julia.lawall@lip6.fr>,
	Joe Perches <joe@perches.com>, Derek Robson <robsonde@gmail.com>,
	w.d.hubbs@gmail.com, chris@the-brannons.com, kirk@reisers.ca,
	samuel.thibault@ens-lyon.org, gregkh@linuxfoundation.org,
	shraddha.6596@gmail.com, alan@linux.intel.com, shiva@exdev.nl,
	amitoj1606@gmail.com, amsfield22@gmail.com, bhumirks@gmail.com,
	waltfeasel@gmail.com, speakup@linux-speakup.org,
	devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org
Subject: Re: Staging: speakup - syle fix permissions to octal
Date: Sat, 4 Feb 2017 16:25:20 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1702041623580.1959@hadrien> (raw)
In-Reply-To: <73e1fc67-804c-ba28-178f-82224c54bb7c@roeck-us.net>

On Sat, 4 Feb 2017, Guenter Roeck wrote:

> On 02/04/2017 06:29 AM, Julia Lawall wrote:
> >
> >
> > On Sat, 4 Feb 2017, Guenter Roeck wrote:
> >
> > > On 02/03/2017 11:27 PM, Joe Perches wrote:
> > > > (adding Julia Lawall)
> > > >
> > > > On Fri, 2017-02-03 at 20:44 -0800, Guenter Roeck wrote:
> > > > > On Sat, Jan 28, 2017 at 07:05:09PM +1300, Derek Robson wrote:
> > > > > > A style fix across whole driver.
> > > > > > changed permissions to octal style, found using checkpatch
> > > > > >
> > > > > > Signed-off-by: Derek Robson <robsonde@gmail.com>
> > > > >
> > > > > FWIW, I think changes like this are best done using coccinelle.
> > > >
> > > > I think checkpatch does it reasonably well.
> > > >
> > > > Julia?  Can coccinelle do this?
> > > >
> > > > I believe cocinelle doesn't handle the substitution
> > > > and octal addition very well when multiple flags
> > > > are used.
> > > >
> > >
> > > Why not ? Seems to be quite simple. One just has to list all the variants
> > > being used in the rule.
> > >
> > > > > That ensures that the results can be reproduced and are well defined.
> > > > > As it is, someone will have to check each line of your patches to
> > > > > ensure
> > > > > that the conversion is correct.
> > > > >
> > > > > It would also ensure (hopefully) that we don't end up with constructs
> > > > > such as
> > > > >
> > > > > > -#define USER_R (S_IFREG|S_IRUGO)
> > > > > > -#define USER_W (S_IFREG|S_IWUGO)
> > > > > > +#define USER_R (S_IFREG|0444)
> > > > > > +#define USER_W (S_IFREG|0666)
> > > > >
> > > > > which really defeat the purpose of the whole exercise.
> > > >
> > > > Why do you think mixing file specific attributes
> > > > with octal permissions is a bad thing?
> > > >
> > >
> > > Just an assumption. My bad. Ultimately, what I think doesn't really
> > > matter, though - because what I think is that the whole "use octals"
> > > is a bad idea to start with.
> >
> > I don't think I have received yet the message that this is referring to.
> > But I don't see a problem for Coccinelle a priori.  If there are things
> > that need to be added together, as long as they are explicit constants,
> > that can be done in python or ocaml.
> >
>
> Something like
>
> @@
> @@
>
> (
> - S_IFREG | S_IRUGO | S_IWUGO
> + S_IFREG | 0666
> |
> - S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH
> + 0644
> |
> - S_IRUGO|S_IWUSR
> + 0644
> |
> - S_IWUSR|S_IRUGO
> + 0644
> |
> - S_IRUGO|S_IWUGO
> + 0666
> |
> - S_IWUGO|S_IRUGO
> + 0666
> |
> - S_IRUGO
> + 0444
> |
> - S_IWUGO
> + 0222
> |
> - S_IWUSR
> + 0200
> )
>
> Odd is that the S_IFREG rule seems to be needed to catch "S_IFREG | S_IRUGO |
> S_IWUGO",
> but probably I am missing something as usual ;-).

The associativity of | is not what you hope for.

julia