On Wed, Feb 9, 2022 at 2:27 PM Mauricio Vásquez <mauricio@xxxxxxxxxx> wrote:
>
> From: Rafael David Tinoco <rafaeldtinoco@xxxxxxxxx>
>
> Add "min_core_btf" feature explanation and one example of how to use it
> to bpftool-gen man page.
>
> 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>
> ---
> .../bpf/bpftool/Documentation/bpftool-gen.rst | 93 +++++++++++++++++++
> 1 file changed, 93 insertions(+)
>
[...]
> +Now, the "5.4.0-smaller.btf" file may be used by libbpf as an external BTF file
> +when loading the "one.bpf.o" object into the "5.4.0-example" kernel. Note that
> +the generated BTF file won't allow other eBPF objects to be loaded, just the
> +ones given to min_core_btf.
> +
> +::
> +
> + struct bpf_object *obj = NULL;
> + struct bpf_object_open_opts openopts = {};
> +
> + openopts.sz = sizeof(struct bpf_object_open_opts);
> + openopts.btf_custom_path = "./5.4.0-smaller.btf";
> +
> + obj = bpf_object__open_file("./one.bpf.o", &openopts);
Can you please use LIBBPF_OPTS() macro in the example, that's how
users are normally expected to use OPTS-based APIs anyways. Also there
is no need for "./" when specifying file location. This is a different
case than running a binary in the shell, where binary is searched in
PATH. This is never done when opening files.
So all this should be:
LIBBPF_OPTS(bpf_object_open_opts, opts, .btf_custom_path = "5.4.0-smaller.btf");
struct bpf_object *obj;
obj = bpf_object__open_file("one.bpf.o", &opts);
That's all.
> +
> + ...
> --
> 2.25.1
>
