[Buildroot] [PATCH next v6 07/10] core: implement per-package SDK and target
Thomas Petazzoni
thomas.petazzoni at bootlin.com
Wed Dec 26 17:34:22 UTC 2018
Hello,
Arnout, Yann, see below some discussion where your input might be
useful.
On Thu, 6 Dec 2018 11:21:25 +0100, Andreas Naumann wrote:
> Just to make sure I just did the above using your ppsh-v6 branch with
> the wandboard_defconfig. The only additional change was to use the
> external linaro toolchain. After 'make'
> $ readelf -d output/host/sbin/mkfs.ext3
> shows
> 0x000000000000001d (RUNPATH) Bibliothek runpath:
> [/local/gsrc/buildroot.upstream/output/per-package/host-e2fsprogs/host/lib]
>
> which is already unexpected, shouldn't it show .../output/host/lib?
> After 'make prepare-sdk'
> $ readelf -d output/host/sbin/mkfs.ext3
> shows
> 0x000000000000001d (RUNPATH) Bibliothek runpath: []
OK, so I investigated this issue, and now I understand where it comes
from, but I'm not yet sure how to fix it properly.
Basically, *without* per-package directory enabled, the RPATH of
binaries looks like this:
Library rpath: [/home/thomas/projets/buildroot/output/host/lib]
then, support/scripts/fix-rpath calls patchelf with the following
invocation:
/home/thomas/projets/buildroot/output/host/bin/patchelf --make-rpath-relative /home/thomas/projets/buildroot/output/host --relative-to-file /home/thomas/projets/buildroot/output/host/sbin/mke2fs
This works fine, and causes the resulting binary to have the following
RPATH:
Library runpath: [$ORIGIN/../lib]
You can see that the original "Library rpath", which
is /home/thomas/projets/buildroot/output/host/lib is located *inside*
the ROOTDIR passed as the --make-rpath-relative
option: /home/thomas/projets/buildroot/output/host.
Now, with per-package directory enabled, the RPATH of binaries when
building looks like this:
Library rpath: [/home/thomas/projets/buildroot/output/per-package/host-e2fsprogs/host/lib]
So it is no longer within the ROOTDIR passed as patchelf's
--make-rpath-relative argument.
The logic used by patchelf is explained in
package/patchelf/0003-Add-option-to-make-the-rpath-relative-under-a-specif.patch:
====
RPATHDIR starts with "$ORIGIN":
The original build-system already took care of setting a relative
RPATH, resolve it and test if it's valid (does exist)
RPATHDIR starts with ROOTDIR:
The original build-system added some absolute RPATH (absolute on
the build machine). Test if it's valid (does exist).
ROOTDIR/RPATHDIR exists:
The original build-system already took care of setting an absolute
RPATH (absolute in the final rootfs), resolve it and test if it's
valid (does exist).
RPATHDIR points somewhere else:
(can be anywhere: build trees, staging tree, host location,
non-existing location, etc.). Just discard such a path.
====
So, without per-package directory, we fall in case (2) above.
With per-package directory, we fall in case (4) above, and therefore
the RPATH is discarded.
At this point, I am not sure at which level and how the issue should be
fixed. Needs some thought. Input/ideas welcome.
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
More information about the buildroot
mailing list