[systemd-devel] [PATCH 2/5] udev.pc: install to pkgconfiglibdir

[Kay Sievers]

On Wed, Apr 8, 2015 at 7:34 PM, Marc-Antoine Perennou
<Marc-Antoine at perennou.com> wrote:
> On 8 April 2015 at 18:47, Kay Sievers <kay at vrfy.org> wrote:
>> On Tue, Apr 7, 2015 at 8:54 PM, Marc-Antoine Perennou
>> <Marc-Antoine at perennou.com> wrote:
>>> ---
>>>  Makefile.am | 3 +--
>>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>>
>>> diff --git a/Makefile.am b/Makefile.am
>>> index 9fa4223..9b769ee 100644
>>> --- a/Makefile.am
>>> +++ b/Makefile.am
>>> @@ -3725,8 +3725,7 @@ udevconfdir = $(sysconfdir)/udev
>>>  dist_udevconf_DATA = \
>>>         src/udev/udev.conf
>>>
>>> -sharepkgconfigdir = $(datadir)/pkgconfig
>>> -sharepkgconfig_DATA = \
>>> +pkgconfiglib_DATA += \
>>>         src/udev/udev.pc
>>
>> This is all backwards. The systemd.pc file is also in the wrong location.
>>
>> These GENERIC files are supposed to be found by the primary AND the
>> secondary arch at the same time, at the GENERIC location, not in a
>> arch-specific libdir.
>>
>> How would the 32bit build find this file on a 64bit compat-arch/multilib system?
>>
>> Kay
>
> Well, let's imagine a full cross-compilation toolchain, with
> CHOST-prefixed tools.
>
> x86_64 stuff will get built with x86_64-pc-linux-gnu-gcc
> i686 stuff will get built with i686-pc-linux-gnu-gcc
> (and you could add a lot of non-native archs here like arm, mips & co)
>
> x86_64-pc-linux-gnu-pkg-config will look into /usr/lib64/pkgconfig and
> /usr/share/pkgconfig
> i686-pc-linux-gnu-pkg-config will look into /usr/lib32/pkgconfig and
> /usr/share/pkgconfig
>
> You says that systemd is in the wrong location, so let's see what's
> going on with its
> current location, and then if we move it to /usr/share
>
> Current location, libdir/pkgconfig/systemd.pc
>
> x86_64-pc-linux-gnu-pkg-config finds /usr/lib64/pkgconfig/systemd.pc containing,
> amongst other things, libdir which is arch specific, /usr/lib64 and
> systemdutildir
> which contains arch-specific binaries (yes, /usr/lib64/systemd/systemd *is* an
> ELF64 binary using an x86_64 interpreter.
>
> i686-pc-linux-gnu-pkg-config finds /usr/lib32/pkgconfig/systemd.pc (since it has
> been cross-compiled too) and is pretty happy with that.
>
> arm-whatever-pkg-config finds /usr/arm-whatever/lib/systemd.pc and is
> happy with it.
>
> If you move it to /usr/share/pkgconfig
>
> x86_64-pc-linux-gnu-pkg-config finds /usr/share/pkgconfig/systemd.pc
> and is happy with it
>
> i686-pc-linux-gnu-pkg-config finds /usr/share/pkgconfig/systemd.pc and
> tries linking to
> x86_64 libraries
>
> arm-whatever-pkg-config finds /usr/share/pkgconfig/systemd.pc and
> tries linking to
> x86_64 libraries + it gets the path towards binaries its target won't
> even be able to execute.
>
>
> Hope that helps understanding the rational of putting pkgconfig files
> pointing to
> arch-specific libs/bins into an arch-specific place.
>
>
> A good example of a pkgconfig file that is ok to install into
> /usr/share/pkgconfig is
> xorg-macros.pc which only leads to arch-independants macros.

The point is, the purpose of that file is not cross-compiling. It is
meant to provide information for the i686 toolchain which is nativly
compiled on a x86_64 primary host.

How is the i686 tool supposed to find the primary values of the
installed native x86_64 tools if things are moved like you propose?

The entire idea of adding $libdir to a file that is installed in
$libdir to point to itself makes no sense at all, but that was the
reason it was moved in the first place.

Kay