[Buildroot] [PATCH 2/2] microperl: install host-microperl in $(HOST_DIR)/opt/perl

[Will Newton]

On Wed, Mar 28, 2012 at 2:01 PM, Will Newton <will.newton at gmail.com> wrote:
> On Wed, Mar 28, 2012 at 1:52 PM, Thomas Petazzoni
> <thomas.petazzoni at free-electrons.com> wrote:
>> Le Wed, 28 Mar 2012 12:55:47 +0200,
>> Thomas Petazzoni <thomas.petazzoni at free-electrons.com> a écrit :
>>
>>> In the past, we had the problem that when we were building target
>>> packages that required host utilities installed in $(HOST_DIR)/usr/bin,
>>> those utilities were not able to find their libraries in
>>> $(HOST_DIR)/usr/lib. We tried using LD_LIBRARY_PATH, but libtool used
>>> it as the search path for libraries when compiling target stuff. So, we
>>> decided to hardcode the correct rpath in all binaries built and
>>> installed in $(HOST_DIR)/usr/bin.
>>
>> I had a quick look at this, and here the Perl dynamic module that
>> depends on libexpat.so.1 is built with the correct RPATH:
>>
>> $ arm-linux-gnueabi-readelf -a host/usr/lib/perl/auto/XML/Parser/Expat/Expat.so | grep RPATH
>>  0x000000000000000f (RPATH)              Library rpath: [/opt/outputs/perl/host/usr/lib]
>>
>> So normally, when this Expat.so library is dlopen'ed by Perl, it should
>> use the RPATH of Expat.so to find where libexpat.so.1 is located. And
>> on my system, it does:
>>
>> $ PERLLIB=/opt/outputs/perl/host/usr/lib/perl/ LD_DEBUG=libs perl -e 'require XML::Parser;'
>>      9529:     find library=libperl.so.5.10 [0]; searching
>>      9529:      search cache=/etc/ld.so.cache
>>      9529:       trying file=/usr/lib/libperl.so.5.10
>>      9529:
>>      9529:     find library=libdl.so.2 [0]; searching
>>      9529:      search cache=/etc/ld.so.cache
>>      9529:       trying file=/lib/x86_64-linux-gnu/libdl.so.2
>>      9529:
>>      9529:     find library=libm.so.6 [0]; searching
>>      9529:      search cache=/etc/ld.so.cache
>>      9529:       trying file=/lib/x86_64-linux-gnu/libm.so.6
>>      9529:
>>      9529:     find library=libpthread.so.0 [0]; searching
>>      9529:      search cache=/etc/ld.so.cache
>>      9529:       trying file=/lib/x86_64-linux-gnu/libpthread.so.0
>>      9529:
>>      9529:     find library=libc.so.6 [0]; searching
>>      9529:      search cache=/etc/ld.so.cache
>>      9529:       trying file=/lib/x86_64-linux-gnu/libc.so.6
>>      9529:
>>      9529:     find library=libcrypt.so.1 [0]; searching
>>      9529:      search cache=/etc/ld.so.cache
>>      9529:       trying file=/lib/x86_64-linux-gnu/libcrypt.so.1
>>      9529:
>>      9529:
>>      9529:     calling init: /lib/x86_64-linux-gnu/libpthread.so.0
>>      9529:     calling init: /lib/x86_64-linux-gnu/libc.so.6
>>      9529:     calling init: /lib/x86_64-linux-gnu/libcrypt.so.1
>>      9529:     calling init: /lib/x86_64-linux-gnu/libm.so.6
>>      9529:     calling init: /lib/x86_64-linux-gnu/libdl.so.2
>>      9529:     calling init: /usr/lib/libperl.so.5.10
>>      9529:
>>      9529:
>>      9529:     initialize program: perl
>>      9529:     transferring control: perl
>>      9529:
>>      9529:     find library=libexpat.so.1 [0]; searching
>>      9529:      search path=/opt/outputs/perl/host/usr/lib/tls/x86_64:/opt/outputs/perl/host/usr/lib/tls:/opt/outputs/perl/host/usr/lib/x86_64:/opt/outputs/perl/host/usr/lib          (RPATH from file /opt/outputs/perl/host/usr/lib/perl//auto/XML/Parser/Expat/Expat.so)
>>      9529:       trying file=/opt/outputs/perl/host/usr/lib/tls/x86_64/libexpat.so.1
>>      9529:       trying file=/opt/outputs/perl/host/usr/lib/tls/libexpat.so.1
>>      9529:       trying file=/opt/outputs/perl/host/usr/lib/x86_64/libexpat.so.1
>>      9529:       trying file=/opt/outputs/perl/host/usr/lib/libexpat.so.1
>>      9529:
>>      9529:     calling init: /opt/outputs/perl/host/usr/lib/libexpat.so.1
>>      9529:     calling init: /opt/outputs/perl/host/usr/lib/perl//auto/XML/Parser/Expat/Expat.so
>>      9529:     calling fini: perl [0]
>>      9529:     calling fini: /usr/lib/libperl.so.5.10 [0]
>>      9529:     calling fini: /lib/x86_64-linux-gnu/libdl.so.2 [0]
>>      9529:     calling fini: /lib/x86_64-linux-gnu/libm.so.6 [0]
>>      9529:     calling fini: /lib/x86_64-linux-gnu/libpthread.so.0 [0]
>>      9529:     calling fini: /lib/x86_64-linux-gnu/libcrypt.so.1 [0]
>>      9529:     calling fini: /opt/outputs/perl/host/usr/lib/perl//auto/XML/Parser/Expat/Expat.so [0]
>>      9529:     calling fini: /opt/outputs/perl/host/usr/lib/libexpat.so.1 [0]
>>      9529:     calling fini: /lib/x86_64-linux-gnu/libc.so.6 [0]
>>
>> As you can see here, it clearly looks in the RPATH encoded into
>> Expat.so to find where libexpat.so.1 is located. In my
>> case /opt/outputs/perl/ in the Buildroot output directory, and it
>> clearly uses the libexpat.so.1 from this output directory, and not the
>> one from my system.
>>
>> Are you sure you don't have any value set in your LD_LIBRARY_PATH
>> environment variable (outside of Buildroot)? Can you try the commands
>> above (check the RPATH of Expat.so and check the resolution of
>> libraries when asking Perl to require the XML::Parser module, when
>> PERLLIB points to the Perl modules built by Buildroot), and post the
>> results?
>
> I haven't got any LD_LIBRARY_PATH set, but it looks like there is no
> rpath set. I wonder if this is some perl Makefile issue.
>
> [win at lemeta01 buildroot]$ env | grep LD_LIBRARY
> [win at lemeta01 buildroot]$ ./output/host/usr/bin/arm-linux-readelf -a
> ./output/host/usr/lib/perl/auto/XML/Parser/Expat/Expat.so | grep RPATH
> [win at lemeta01 buildroot]$
>
> Although the makefiles do mention rpath, but that one does not seem to
> be getting used either:
>
> [win at lemeta01 host-libxml-parser-perl-2.36]$ grep -ri rpath *
> Expat/Makefile:CCDLFLAGS = -Wl,-E
> -Wl,-rpath,/usr/lib64/perl5/5.8.8/x86_64-linux-thread-multi/CORE
> Makefile:CCDLFLAGS = -Wl,-E
> -Wl,-rpath,/usr/lib64/perl5/5.8.8/x86_64-linux-thread-multi/CORE

However it does use LD_RUN_PATH:

[win at lemeta01 host-libxml-parser-perl-2.36]$ grep -r LD_RUN_PATH *
Expat/Makefile:LD_RUN_PATH = /meta/home/win/buildroot/output/host/usr/lib

If I change that line to "export LD_RUN_PATH..." it seems to set the
rpath and work correctly...