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Date: Thu, 10 Oct 2013 15:47:45 -0700
From: ebiederm@...ssion.com (Eric W. Biederman)
To: Sebastian Capella <sebastian.capella@...aro.org>
Cc: "Andrew Morton" <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linaro-kernel@...ts.linaro.org, patches@...aro.org,
"Serge Hallyn" <serge.hallyn@...onical.com>,
"Stephen Warren" <swarren@...dia.com>,
"Jens Axboe" <axboe@...nel.dk>,
"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
"Al Viro" <viro@...iv.linux.org.uk>
Subject: Re: [PATCH v3 1/2] init/do_mounts.c: ignore final \n in name_to_dev_t
Sebastian Capella <sebastian.capella@...aro.org> writes:
> Quoting Sebastian Capella (2013-10-03 16:47:35)
>> Quoting Sebastian Capella (2013-10-03 14:42:46)
>> > Quoting Andrew Morton (2013-10-03 14:15:23)
>> > > On Thu, 3 Oct 2013 14:10:37 -0700 Sebastian Capella <sebastian.capella@...aro.org> wrote:
>> > >
>> > > > Enhance name_to_dev_t to handle trailing newline characters
>> > > > on device paths. Some inputs to name_to_dev_t may come from
>> > > > userspace where oftentimes a '\n' is appended to the path.
>> > > > Added const to the name buffer in both the function
>> > > > declaration and the prototype to reflect input buffer
>> > > > handling.
>> > > >
>> > > > By handling trailing newlines in name_to_dev_t, userspace
>> > > > buffers may be directly passed to name_to_dev_t without
>> > > > modification.
>> > >
>> > > We have lib/string.c:strim() - perhaps this patch would be
>> > > neater if it were to use it?
>> >
>> > Hi Morton,
>> >
>> > I was intending to respect the const handling of the input buffer.
>> >
>> > The actual buffer in this case is not really const as it comes from
>> > the file buffering, but removing the const requires changing the
>> > store function defined in the kobj_attribute, and would propagate
>> > to many areas in the kernel.
>> >
>> > Modifying the buffer and removing the const was also suggested by Pavel.
>> > After some discussion I posted this version which did not change the
>> > buffer or the prototype.
>> >
>> > Please let me know if the preference is to modify the store function
>> > definition.
>> >
>> > I'll prepare a patchset that removes the consts to see how much is
>> > changed.
>> >
>> > Thanks,
>> >
>> > Sebastian
>>
>> Hi Andrew,
>>
>> Sorry for calling you Morton earlier.
>>
>> I looked into removing the const from the store function, but I'm not sure
>> this is the right idea, so I'm going to shelf that for now.
>>
>> Please let me know your thoughts.
>>
>> Thanks,
>>
>> Sebastian
>
> Ping...
>
> Hi Andrew,
>
> Do you have any feedback on this?
>
> Below are the three options considered thus far. Do
> you have any additional suggestions or preferences?
What is wrong with requiring userspace to use echo -n ?
That by far seems the simplest and least error prone solution.
Eric
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