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

[Marc-Antoine Perennou]

On 8 April 2015 at 20:02, Kay Sievers <kay at vrfy.org> wrote:
> On Wed, Apr 8, 2015 at 7:52 PM, Marc-Antoine Perennou
> <Marc-Antoine at perennou.com> wrote:
>> On 8 April 2015 at 19:46, Kay Sievers <kay at vrfy.org> wrote:
>>> 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?
>>>
>>
>> Why would it need to?
>
> Because it is the purpose of that file. The version of systemd which
> is installed is described in that file. Tools that build on this host
> want the values of this systemd.
>
>>> 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.
>>
>> Agreed about the redundancy, but what if the arm tool wants to find
>> installed arm tools, and not x86_64?
>
> This is not a systemd problem. Systemd is the base system, and that is
> described in that file, not something that is foreign to the base
> system.
>
> With the original intended purpose of these files, they just belong
> into one single common location describing the currently
> running/primary/common system values.
>
> $libdir was added to indicate the primary architecture. That only
> makes sense when the file is in a common location, not in libdir. Like
> described in the man page:
>   http://www.freedesktop.org/software/systemd/man/file-hierarchy.html#/usr/lib/arch-id
>
> Kay

Even if I don't fully agree with it, I understand your point, we'll
then maintain this patch downstream.

Thanks for the details about this refusal.

Marc-Antoine