On Fri, Jan 21, 2022 at 12:40 PM Mauricio Vásquez Bernal <mauricio@xxxxxxxxxx> wrote: > > On Wed, Jan 12, 2022 at 1:08 PM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote: > > > > 2022-01-12 09:27 UTC-0500 ~ Mauricio Vásquez <mauricio@xxxxxxxxxx> > > > This command is implemented under the "gen" command in bpftool and the > > > syntax is the following: > > > > > > $ bpftool gen btf INPUT OUTPUT OBJECT(S) > > > > Thanks a lot for this work! > > > > Please update the relevant manual page under Documentation, to let users > > know how to use the feature. You may also consider adding an example at > > the end of that document. > > > > We're working on it, and will be part of the next spin. > > > The bash completion script should also be updated with the new "btf" > > subcommand for "gen". Given that all the arguments are directories and > > files, it should not be hard. > > > > Will do. > > > Have you considered adding tests for the feature? There are a few > > bpftool-related selftests under tools/testing/selftests/bpf/. > > > > Yes, we have but it seems not that trivial. One idea I have is to > include a couple of BTF source files from > https://github.com/aquasecurity/btfhub-archive/ and create a test > program that generates some field, type and enum relocations. Then we > could check if the generated BTF file has the expected types, fields > and so on by parsing it and using the BTF API from libbpf. One concern > about it is the size of those two source BTF files (~5MB each), > perhaps we should not include a full file but something that is > already "trimmed"? Another possibility is to use > "/sys/kernel/btf/vmlinux" but it'll limit the test to machines with > CONFIG_DEBUG_INFO_BTF. > > Do you have any ideas / feedback on this one? Should the tests be > included in this series or can we push them later on? See how we test CO-RE relocations and how we use C files to get custom BTFs. See progs/btf_* and prog_tests/core_reloc.c selftests. You don't have to use real vmlinux BTF to test this functionality. > > > > > > > INPUT can be either a single BTF file or a folder containing BTF files, > > > when it's a folder, a BTF file is generated for each BTF file contained > > > in this folder. OUTPUT is the file (or folder) where generated files are > > > stored and OBJECT(S) is the list of bpf objects we want to generate the > > > BTF file(s) for (each generated BTF file contains all the types needed > > > by all the objects). > > > > > > Signed-off-by: Mauricio Vásquez <mauricio@xxxxxxxxxx> > > > Signed-off-by: Rafael David Tinoco <rafael.tinoco@xxxxxxxxxxx> > > > Signed-off-by: Lorenzo Fontana <lorenzo.fontana@xxxxxxxxxx> > > > Signed-off-by: Leonardo Di Donato <leonardo.didonato@xxxxxxxxxx> > > > --- > > > tools/bpf/bpftool/gen.c | 117 ++++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 117 insertions(+) > > > [...]
