udev, input/linux.h and cross compilation

udev, input/linux.h and cross compilation

[Paul Bender]

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The top level Makefile.am hard codes /usr/include/linux/input.h for use 
in the generation of extras/keymap/keys.txt. Such hard coding does not 
work when cross compiling as the linux/input.h file that should be used 
is the cross environment's linux/include.h not /usr/include/linux/input.h.

I have attached a patch that determines the correct linux/include.h file 
during configure. The configure change makes use of the 
AX_ABOLUTE_HEADER 
http://www.nongnu.org/autoconf-archive/ax_absolute_header.html, which 
the patch adds to the m4.

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Re: udev, input/linux.h and cross compilation

[Kay Sievers]

On Wed, Jan 20, 2010 at 19:21, Paul Bender <pebender@san.rr.com> wrote:
> The top level Makefile.am hard codes /usr/include/linux/input.h for use in
> the generation of extras/keymap/keys.txt. Such hard coding does not work
> when cross compiling as the linux/input.h file that should be used is the
> cross environment's linux/include.h not /usr/include/linux/input.h.
>
> I have attached a patch that determines the correct linux/include.h file
> during configure. The configure change makes use of the AX_ABOLUTE_HEADER
> http://www.nongnu.org/autoconf-archive/ax_absolute_header.html, which the
> patch adds to the m4.

Why is all this magic needed? Can't you just use:
  extras/keymap/keys.txt: $(includedir)/linux/input.h

Thanks,
Kay

Re: udev, input/linux.h and cross compilation

[Paul Bender]

On 1/20/2010 10:30 AM, Kay Sievers wrote:
> On Wed, Jan 20, 2010 at 19:21, Paul Bender<pebender@san.rr.com>  wrote:
>> The top level Makefile.am hard codes /usr/include/linux/input.h for use in
>> the generation of extras/keymap/keys.txt. Such hard coding does not work
>> when cross compiling as the linux/input.h file that should be used is the
>> cross environment's linux/include.h not /usr/include/linux/input.h.
>>
>> I have attached a patch that determines the correct linux/include.h file
>> during configure. The configure change makes use of the AX_ABOLUTE_HEADER
>> http://www.nongnu.org/autoconf-archive/ax_absolute_header.html, which the
>> patch adds to the m4.
>
> Why is all this magic needed? Can't you just use:
>    extras/keymap/keys.txt: $(includedir)/linux/input.h
>
> Thanks,
> Kay

Using ${includedir} is not sufficient because ${includedir} is in the 
run time path. The cross build files are installed in 
${DESTDIR}${includedir} not ${includedir} on the build system.

For me, ${DESTDIR}${includedir} would be sufficient. However, I figured 
that depending on a detection macro used by (and therefore fixed for) 
multiple packages on multiple distributions was better than hard coding 
${DESTDIR}${includedir}.

Re: udev, input/linux.h and cross compilation

[Martin Pitt]

Hello,

Paul Bender [2010-01-20 10:21 -0800]:
> The top level Makefile.am hard codes /usr/include/linux/input.h for
> use in the generation of extras/keymap/keys.txt. Such hard coding
> does not work when cross compiling as the linux/input.h file that
> should be used is the cross environment's linux/include.h not
> /usr/include/linux/input.h.

Could we use

  $ echo '#include <linux/input.h>' | cpp -M | xargs -n1 | grep linux/input.h
  /usr/include/linux/input.h

to figure out the real path?

Martin
-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)

Re: udev, input/linux.h and cross compilation

[Paul Bender]

On 1/21/2010 3:00 AM, Martin Pitt wrote:
> echo '#include<linux/input.h>' | cpp -M | xargs -n1 | grep linux/input.h

I believe that would work once cpp is replaced with $ac_cpp so that the 
correct cpp is used (the one pointed to by $CPP) and the correct cpp 
flags are used (the flags in $CPPFLAGS). However, it adds dependencies 
on grep and xargs, both of which would need to be tested for.

Re: udev, input/linux.h and cross compilation

[Dan Nicholson]

On Thu, Jan 21, 2010 at 5:29 PM, Paul Bender <pebender@san.rr.com> wrote:
> On 1/21/2010 3:00 AM, Martin Pitt wrote:
>>
>> echo '#include<linux/input.h>' | cpp -M | xargs -n1 | grep linux/input.h
>
> I believe that would work once cpp is replaced with $ac_cpp so that the
> correct cpp is used (the one pointed to by $CPP) and the correct cpp flags
> are used (the flags in $CPPFLAGS). However, it adds dependencies on grep and
> xargs, both of which would need to be tested for.

I'm pretty sure libtool is already using grep. However, here's an
alternative just using sed:

echo '#include <linux/input.h>' | cpp -M | sed -n
'/linux\/input.h/s,.* \(.*linux/input.h\).*,\1,p'

--
Dan

Re: udev, input/linux.h and cross compilation

[Kay Sievers]

On Fri, Jan 22, 2010 at 15:02, Dan Nicholson <dbn.lists@gmail.com> wrote:
> On Thu, Jan 21, 2010 at 5:29 PM, Paul Bender <pebender@san.rr.com> wrote:
>> On 1/21/2010 3:00 AM, Martin Pitt wrote:
>>>
>>> echo '#include<linux/input.h>' | cpp -M | xargs -n1 | grep linux/input.h
>>
>> I believe that would work once cpp is replaced with $ac_cpp so that the
>> correct cpp is used (the one pointed to by $CPP) and the correct cpp flags
>> are used (the flags in $CPPFLAGS). However, it adds dependencies on grep and
>> xargs, both of which would need to be tested for.
>
> I'm pretty sure libtool is already using grep. However, here's an
> alternative just using sed:
>
> echo '#include <linux/input.h>' | cpp -M | sed -n
> '/linux\/input.h/s,.* \(.*linux/input.h\).*,\1,p'

Yeah, looks fine. I ended up with:
  $ echo '#include <linux/errno.h>'| \
    cpp -E| \
    sed '/linux\/errno.h/!d; s:.*"\(.*\)/linux/errno.h".*:\1:; /.*/q'
  /usr/include

to find the prefix for the current system include we can use in the Makefile.

Kay