This patch set adds new libbpf APIs and their bpftool integration that allows to perform static linking of BPF object files. Currently no extern resolution across object files is performed. This is going to be the focus of the follow up patches. But, given amount of code and logic necessary to perform just basic functionality of linking together mostly independent BPF object files, it was decided to land basic BPF linker code and logic first and extend it afterwards. The motivation for BPF static linking is to provide the functionality that is naturally assumed for user-space development process: ability to structure application's code without artificial restrictions of having all the code and data (variables and maps) inside a single source code file. This enables better engineering practices of splitting code into well-encapsulated parts. It provides ability to hide internal state from other parts of the code base through static variables and maps. It is also a first steps towards having generic reusable BPF libraries. Please see individual patches (mostly #6 and #7) for more details. Patch #10 passes all test_progs' individual BPF .o files through BPF static linker, which is supposed to be a no-op operation, so is essentially validating that BPF static linker doesn't produce corrupted ELF object files. Patch #11 adds Makefile infra to be able to specify multi-file BPF object files and adds the first multi-file test to validate correctness. v1->v2: - extracted `struct strset` to manage unique set of strings both for BTF and ELF SYMTAB (patch #4, refactors btf and btf_dedup logic as well) (Alexei); - fixed bugs in bpftool gen command; renamed it to `gen object`, added BASH completions and extended/updated man page (Quentin). Andrii Nakryiko (11): libbpf: expose btf_type_by_id() internally libbpf: generalize BTF and BTF.ext type ID and strings iteration libbpf: rename internal memory-management helpers libbpf: extract internal set-of-strings datastructure APIs libbpf: add generic BTF type shallow copy API libbpf: add BPF static linker APIs libbpf: add BPF static linker BTF and BTF.ext support bpftool: add `gen object` command to perform BPF static linking selftests/bpf: re-generate vmlinux.h and BPF skeletons if bpftool changed selftests/bpf: pass all BPF .o's through BPF static linker selftests/bpf: add multi-file statically linked BPF object file test .../bpf/bpftool/Documentation/bpftool-gen.rst | 65 +- tools/bpf/bpftool/bash-completion/bpftool | 2 +- tools/bpf/bpftool/gen.c | 49 +- tools/lib/bpf/Build | 2 +- tools/lib/bpf/btf.c | 714 +++--- tools/lib/bpf/btf.h | 2 + tools/lib/bpf/btf_dump.c | 8 +- tools/lib/bpf/libbpf.c | 15 +- tools/lib/bpf/libbpf.h | 13 + tools/lib/bpf/libbpf.map | 5 + tools/lib/bpf/libbpf_internal.h | 38 +- tools/lib/bpf/linker.c | 1944 +++++++++++++++++ tools/lib/bpf/strset.c | 176 ++ tools/lib/bpf/strset.h | 21 + tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/Makefile | 21 +- .../selftests/bpf/prog_tests/static_linked.c | 40 + .../selftests/bpf/progs/test_static_linked1.c | 30 + .../selftests/bpf/progs/test_static_linked2.c | 31 + 19 files changed, 2760 insertions(+), 417 deletions(-) create mode 100644 tools/lib/bpf/linker.c create mode 100644 tools/lib/bpf/strset.c create mode 100644 tools/lib/bpf/strset.h create mode 100644 tools/testing/selftests/bpf/prog_tests/static_linked.c create mode 100644 tools/testing/selftests/bpf/progs/test_static_linked1.c create mode 100644 tools/testing/selftests/bpf/progs/test_static_linked2.c -- 2.24.1