2021-11-10 –, Room I
Programs crash. And when they do, they dump core, and we want to tell the user which package, including the version, caused the failure. This talk describes a compact JSON-based format that is embedded directly in the binaries as an ELF note. By embedding the this information directly in the binary object, package information is immediately available from a core dump, independently of any external packaging metadata. This is a cross-distro collaboration, with the eventual goal of having the same metadata automatically added by all distributions.
The general idea is to add a terse JSON note as .note.package ELF note. This note identifies who and where built the binary: the distro or vendor, distro version, package version, architecture, etc. This is useful when programs compiled for different distributions are mixed (e.g. Debian container running on Fedora), when non-distribution programs are used with a distro (e.g. a private program), when distribution metadata has been stripped (e.g. an initrd image), or when only offline access is possible.
This metadata can cooexist with the existing .note.gnu.build-id ELF notes. Those are added by most distributions, but they only provide a build-id hash. To resolve this hash to an actual package name and version, some additional query is required.
Links:
- https://systemd.io/COREDUMP_PACKAGE_METADATA/
- https://github.com/systemd/package-notes
- https://fedoraproject.org/wiki/Changes/Package_information_on_ELF_objects
python, systemd, fedora linux
Debian Developer, member of maintainers teams of DPDK/systemd/ZeroMQ, Software Engineer at Microsoft