Re: [gentoo-portage-dev] [PATCH] Add QA check for unresolved soname dependencies (bug 704320)

[Michael 'veremitz' Everitt]

On 06/01/20 06:38, Zac Medico wrote:
> Example output for maven-bin-3.6.2 (bug 704618):
>
>  * QA Notice: Unresolved soname dependencies:
>  *
>  * 	/usr/share/maven-bin-3.6/lib/jansi-native/freebsd32/libjansi.so: libc.so.7 libutil.so.9
>  * 	/usr/share/maven-bin-3.6/lib/jansi-native/freebsd64/libjansi.so: libc.so.7 libutil.so.9
>  *
>
> This warning comes up when a library or executable has one or
> more soname dependencies (found in its NEEDED.ELF.2 metadata)
> that could not be resolved by usual means. If you run ldd
> on files like these then it will report a "not found" error
> for each unresolved soname dependency. In order to correct
> problems with soname dependency resolution, use one or more
> of the approaches described in the following sections.
>
> Content of the NEEDED.ELF.2 metadata file may be useful
> for debugging purposes. Find the NEEDED.ELF.2 file in the
> ${D}/../build-info/ directory after the ebuild src_install
> phase completes, or in the /var/db/pkg/*/*/ directory for an
> installed package. Each line of the NEEDED.ELF.2 file contains
> semicolon separated values for a single ELF file. The soname
> dependencies are found in the DT_NEEDED column:
>
>  E_MACHINE;path;DT_SONAME;DT_RUNPATH;DT_NEEDED;multilib category
>
> External dependencies
>
> For packages that install pre-built binaries, it may be possible
> to resolve soname dependencies simply by adding dependencies
> for one or more other packages that are known to provide the
> needed sonames.
>
> Removal of unecessary files
>
> For packages that install pre-built binaries, it may be possible
> to resolve soname dependencies simply by removing unnecessary
> files which have unresolved soname dependencies. For example,
> some pre-built binary packages include binaries intended for
> irrelevant architectures or operating systems, and these files
> can simply be removed because they are unnecessary.
>
> Addition of DT_RUNPATH entries
>
> If the relevant dependencies are installed in a location that
> is not included in the dynamic linker search path, then it's
> necessary for files to include a DT_RUNPATH entry which refers
> to the appropriate directory. The special $ORIGIN value can
> be used to create a relative path reference in DT_RUNPATH,
> where $ORIGIN is a placeholder for the directory where the
> file having the DT_RUNPATH entry is located.
>
> For pre-built binaries, it may be necessary to fix up
> DT_RUNPATH using patchelf --set-rpath. For example, use
> patchelf --set-rpath '$ORIGIN' if a given binary should link
> to libraries found in the same directory as the binary itself,
> or use patchelf --set-rpath '$ORIGIN/libs' if a given binary
> should link to libraries found in a subdirectory named libs
> found in the same directory as the binary itself.
>
> For binaries built from source, a flag like
> -Wl,-rpath,/path/of/directory/containing/libs will create
> binaries with the desired DT_RUNPATH entry.
>
> Bug: https://bugs.gentoo.org/704320
> Signed-off-by: Zac Medico <zmedico@g.o>
> ---
<snip>

Looks awesome!

One comment: would it be helpful for developers/maintainers to have some
indication of what's going on here, and what attempts portage is making in
this regard? Something like a 'verbose' option that would spit out some
debugging info so that /if/ something goes wrong, or the outcome wasn't
what was intended, then this can be picked up and corrected somehow else?

I think automation is great for picking these issues up, and shining a
light on where/why something goes wrong, but sometimes it needs a few
minutes of human intervention to achieve the sane outcome in many
circumstances.