On Thu, 4 Apr 2024 at 00:41, Stephen Hemminger <step...@networkplumber.org> wrote: > > On Wed, 3 Apr 2024 22:19:20 +0100 > Luca Boccassi <bl...@debian.org> wrote: > > > On Wed, 3 Apr 2024 at 16:55, Stephen Hemminger > > <step...@networkplumber.org> wrote: > > > > > > On Wed, 03 Apr 2024 12:50:35 +0100 > > > Luca Boccassi <bl...@debian.org> wrote: > > > > > > > Using bpftool to generate the header at build time is a bit icky, > > > > because it will look at sysfs on the build system, which is from the > > > > running kernel. But a build system's kernel might be some ancient LTS, > > > > and even be a completely different kconfig/build/distro from the actual > > > > runtime one. > > > > > > One other option would be to ship a pre-built skeleton file. > > > Which is what the method the old code did. > > > But that creates an implied dependency on the developers machine build > > > environment. > > > > That's what the distro-provided vmlinux.h should help with - by > > #include'ing that, it should be possible to build a co-re bpf program, > > no other artifacts needed. You can try it out locally by generating it > > from the local running kernel on your dev machine: > > > > bpftool btf dump file /sys/kernel/btf/vmlinux format c > vmlinux.h > > Not all distros are providing vmlinux.h. > And some like Ubuntu haven't figured out how to package bpftool and libbpf > correctly.
Yes and for those the usual pattern is a fallback to generate at build time, if no pre-prepared vmlinux.h is configured
