[systemd-devel] Storing package metadata in ELF objects

[Luca Boccassi]

On Sat, 2021-04-10 at 13:29 +0100, Luca Boccassi wrote:
> Hello,
> 
> Cross-posting to the mailing lists of a few relevant projects.
> 
> After an initial discussion [0], recently we have been working on a new
> specification [0] to encode rich package-level metadata inside ELF
> objects, so that it can be included automatically in generated coredump
> files. The prototype to parse this in systemd-coredump and store the
> information in systemd-journal is ready for testing and merged
> upstream. We are now seeking further comments/opinions/suggestions, as
> we have a few months before the next release and thus there's plenty of
> time to make incompatible changes to the format and implementation, if
> required.
> 
> A proposal to use this by default for all packages built in Fedora 35
> has been submitted [1].
> 
> The Fedora Wiki and the systemd.io document have more details, but to
> make a long story short, a new .notes.package section with a JSON
> payload will be included in ELF objects, encoding various package-
> build-time information like distro name&version, package name&version,
> etc.
> 
> To summarize from the discussion, the main reasons why we believe this
> is useful are as following:
> 
> 1) minimal containers: the rpm database is not installed in the
> containers. The information about build-ids needs to be stored
> externally, so package name information is not available immediately,
> but only after offline processing. The new note doesn't depend on the
> rpm db in any way.
> 
> 2) handling of a core from a container, where the container and host
> have different distros
> 
> 3) self-built and external packages: unless a lot of care is taken to
> keep access to the debuginfo packages, this information may be lost.
> The new note is available even if the repository metadata gets lost.
> Users can easily provide equivalent information in a format that makes
> sense in their own environment. It should work even when rpms and debs
> and other formats are mixed, e.g. during container image creation.
> 
> Other than in Fedora, we are already making the required code changes
> at Microsoft to use the same format&specification for internally-built
> binaries, and for tools that parse core files and logs.
> 
> Tools for RPM and DEB (debhelper) integration are also available [3].

Wrong Fedora list address - off to a great start already :-)
(fixed now)

-- 
Kind regards,
Luca Boccassi
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