[Buildroot] iproute2 binaries getting linked against libelf, which is not available in target

[Buildroot] iproute2 binaries getting linked against libelf, which is not available in target

[Andreas Hilse]

Hi,

I found an issue with buildroot 2020.02.x concerning iproute2 binaries
being linked against libelf.

According to iproute2.mk it should only link against libelf if
BR2_PACKAGE_ELFUTILS is selected.
But it also links against libelf without that option selected and thus
renders the created binaries unusable in the target system.

After digging further I found that this is due to the iproute2 configure
script detecting libelf being available in the used toolchain
(crosstool-ng companion library).

After finding out I can work around this issue.
I thought this might be a thing to be addressed in buildroot, but I'm not
sure how to approach it.

Best regards
Andreas Hilse

[Buildroot] iproute2 binaries getting linked against libelf, which is not available in target

[Thomas Petazzoni]

On Thu, 18 Jun 2020 19:35:48 +0200 (CEST)
Andreas Hilse <andreas.hilse@ipcomm.de> wrote:

> I found an issue with buildroot 2020.02.x concerning iproute2 binaries
> being linked against libelf.
> 
> According to iproute2.mk it should only link against libelf if
> BR2_PACKAGE_ELFUTILS is selected.
> But it also links against libelf without that option selected and thus
> renders the created binaries unusable in the target system.
> 
> After digging further I found that this is due to the iproute2 configure
> script detecting libelf being available in the used toolchain
> (crosstool-ng companion library).

So your crosstool-ng toolchain comes with more libraries than just the
C library ? Buildroot really expects external toolchains to be "pure"
toolchains, i.e with only the C library and no other additional library.

> After finding out I can work around this issue.
> I thought this might be a thing to be addressed in buildroot, but I'm not
> sure how to approach it.

There is no provision in the iproute2 configure script to explicitly
disable a functionality. So we would have to patch this configure
script.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[Buildroot] iproute2 binaries getting linked against libelf, which is not available in target

[Baruch Siach]

Hi Andreas,

On Thu, Jun 18 2020, Andreas Hilse wrote:
> I found an issue with buildroot 2020.02.x concerning iproute2 binaries
> being linked against libelf.
>
> According to iproute2.mk it should only link against libelf if
> BR2_PACKAGE_ELFUTILS is selected.
> But it also links against libelf without that option selected and thus
> renders the created binaries unusable in the target system.
>
> After digging further I found that this is due to the iproute2 configure
> script detecting libelf being available in the used toolchain
> (crosstool-ng companion library).
>
> After finding out I can work around this issue.
> I thought this might be a thing to be addressed in buildroot, but I'm not
> sure how to approach it.

Section 6.1.2 in the Buildroot manual says this:

  We do not support toolchains or SDK generated by OpenEmbedded or
  Yocto, because these toolchains are not pure toolchains (i.e. just
  the compiler, binutils, the C and C++ libraries).

  https://buildroot.org/downloads/manual/manual.html#_cross_compilation_toolchain

Buildroot Can't support an external toolchain that provides its own
build of libelf, or any other library besides what gcc and the C library
provide.

baruch

-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -

[Buildroot] iproute2 binaries getting linked against libelf, which is not available in target

[Andreas Hilse]

Thank you Thomas and Baruch for clarifying!


> Section 6.1.2 in the Buildroot manual says this:
> 
>   We do not support toolchains or SDK generated by OpenEmbedded or
>   Yocto, because these toolchains are not pure toolchains (i.e. just
>   the compiler, binutils, the C and C++ libraries).
> 
> 
> https://buildroot.org/downloads/manual/manual.html#_cross_compilation_to
> olchain
> 
> Buildroot Can't support an external toolchain that provides its own
> build of libelf, or any other library besides what gcc and the C library
> provide.