Re: [PATCH bpf-next v3] selftests/bpf: Use pkg-config to determine ld flags

[Daniel Borkmann]

On 10/16/23 2:43 PM, Akihiko Odaki wrote:
> When linking statically, libraries may require other dependencies to be
> included to ld flags. In particular, libelf may require libzstd. Use
> pkg-config to determine such dependencies.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@xxxxxxxxxx>
> ---
> V2 -> V3: Added missing "echo".
> V1 -> V2: Implemented fallback, referring to HOSTPKG_CONFIG.

Same issue in v3. Please don't resend your patches too quickly, but properly set up an
environment where you can test that this fallback works first :

https://github.com/kernel-patches/bpf/actions/runs/6533309175/job/17738285759

  [...]
  /bin/sh: 1: pkg-config: not found
  /bin/sh: 1: -lelf: not found
    BINARY   test_sysctl
  /usr/bin/x86_64-linux-gnu-ld: /usr/bin/x86_64-linux-gnu-ld: DWARF error: invalid or unhandled FORM value: 0x25
  /tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `bpf_object_open':
  libbpf.c:(.text+0x2871): undefined reference to `elf_version'
  /usr/bin/x86_64-linux-gnu-ld: /tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `bpf_object__elf_finish':
  libbpf.c:(.text+0x4ccf): undefined reference to `elf_end'
  /usr/bin/x86_64-linux-gnu-ld: /tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `elf_find_func_offset_from_archive':
  libbpf.c:(.text+0xb419): undefined reference to `elf_memory'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0xb447): undefined reference to `elf_errmsg'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0xb4e2): undefined reference to `elf_end'
  /usr/bin/x86_64-linux-gnu-ld: /tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `bpf_object__elf_init':
  libbpf.c:(.text+0x10b02): undefined reference to `elf_memory'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10bae): undefined reference to `elf_begin'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10bdd): undefined reference to `elf_errmsg'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10c1b): undefined reference to `elf_kind'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10c54): undefined reference to `gelf_getclass'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10c8d): undefined reference to `elf64_getehdr'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10cd1): undefined reference to `elf_errmsg'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d0f): undefined reference to `elf_getshdrstrndx'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d38): undefined reference to `elf_errmsg'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d72): undefined reference to `elf_getscn'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d7e): undefined reference to `elf_rawdata'
  /usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10da8): undefined reference to `elf_errmsg'