Wrong rpath after linking with libmysqlclient

Hi all,

First of all, the symptomps: build the defconfig in attachment, run with

qemu-system-arm -M nuri -kernel output/images/zImage -append \
"console=ttySAC1,115200" -smp 2 -serial null -serial stdio

and you'll see:

Starting php-fpm /usr/sbin/php-fpm: error while loading shared libraries:
libmysqlclient.so.16: cannot open shared object file: No such file or directory

readelf reveals:

Library rpath: [.../host/usr/arm-buildroot-linux-gnueabi/sysroot/usr/lib/mysql]

i.e. rpath points to staging instead of the on-target directory.

Indeed, in libmysqlclient.la we find:

libdir='.../host/usr/arm-buildroot-linux-gnueabi/sysroot/usr/lib/mysql'

This happens because our 'Fixing libtool files' step makes sure that all
absolute paths have STAGING_DIR prepended to them.

This problem will occur for any library that doesn't install in /lib or
/usr/lib and that uses libtool.

My first idea was to install libmysqlclient.so in /usr/lib instead, but that's
probably a great idea. So the next idea is to skip the libdir= line when fixing up the libtool files. However, I'm not sure if that won't have some other effects (i.e. missing required link flags). But worse, it doesn't even work:
php's libtool still converts it into
-Wl,--rpath -Wl,.../host/usr/arm-buildroot-linux-gnueabi/sysroot/usr/lib/mysql (and gives warnings that the libraries have moved.

Any idea?

A final option is to fix up the rpaths of all ELF files in the target after
build. I believe Yann has a series that does exactl that, no?

Regards,
Arnout

Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
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--
BR2_arm=y
BR2_cortex_a9=y
BR2_ARM_ENABLE_NEON=y
BR2_ARM_FPU_VFPV3D16=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_TARGET_GENERIC_GETTY_PORT="ttySAC1"
BR2_LINUX_KERNEL=y
BR2_LINUX_KERNEL_CUSTOM_VERSION=y
BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="3.10.92"
BR2_LINUX_KERNEL_DEFCONFIG="exynos4"
BR2_LINUX_KERNEL_ZIMAGE=y
BR2_PACKAGE_PHP=y
# BR2_PACKAGE_PHP_EXT_SESSION is not set
# BR2_PACKAGE_PHP_EXT_ZLIB is not set
BR2_PACKAGE_PHP_EXT_MYSQLI=y
BR2_PACKAGE_PHP_SAPI_CLI_FPM=y
BR2_TARGET_ROOTFS_INITRAMFS=y
# BR2_TARGET_ROOTFS_TAR is not set

Arnout, All,

On 2015-12-13 21:07 +0100, Arnout Vandecappelle spake thusly:

that's what Thomas and I were discussing the other day: why are those libraries not in /usr/lib to start with? We believe this should be the case.

The fixup I've been doing is to just get rid of rpath since it should not be needed on the target, as we should expect all NEEDED libraries to either be in /usr/lib or /lib .

Regards,
Yann E. MORIN.

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Hello,

Agreed, all libraries should be in /lib or /usr/lib, so that we can get rid of /etc/ld.so.conf and /etc/ld.so.cache handling, which doesn't work since there is no cross-ldconfig. Yes, it could work without ld.so.conf configuration using rpath, but I don't think it's a good idea.

It would really be preferable if libmysqlclient.so was in /usr/lib like any other libraries.

Thomas

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com