On Sat, Nov 2, 2019 at 3:03 PM Alexei Starovoitov <ast@xxxxxxxxxx> wrote:
>
> Teach libbpf to recognize tracing programs types and attach them to
> fentry/fexit.
>
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> ---
> tools/include/uapi/linux/bpf.h | 2 ++
> tools/lib/bpf/libbpf.c | 55 +++++++++++++++++++++++++++++-----
> tools/lib/bpf/libbpf.h | 2 ++
> tools/lib/bpf/libbpf.map | 1 +
> 4 files changed, 53 insertions(+), 7 deletions(-)
>
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index df6809a76404..69c200e6e696 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -201,6 +201,8 @@ enum bpf_attach_type {
> BPF_CGROUP_GETSOCKOPT,
> BPF_CGROUP_SETSOCKOPT,
> BPF_TRACE_RAW_TP,
> + BPF_TRACE_FENTRY,
> + BPF_TRACE_FEXIT,
> __MAX_BPF_ATTACH_TYPE
> };
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 7aa2a2a22cef..03e784f36dd9 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -3744,7 +3744,7 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
> return 0;
> }
>
> -static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id);
> +static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id, bool raw_tp);
Bools are hard to follow in code, why not just passing full
attach_type instead? It will also be more future-proof, if we need
another trick, similar to "bpf_trace_" prefix for raw_tp?
Also, I have a mild preference for having output arguments to be the
very last in the argument list. Do you mind reordering so thar bool
raw_tp is second?
>
> static struct bpf_object *
> __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
> @@ -3811,7 +3811,9 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
> bpf_program__set_type(prog, prog_type);
> bpf_program__set_expected_attach_type(prog, attach_type);
> if (prog_type == BPF_PROG_TYPE_TRACING) {
> - err = libbpf_attach_btf_id_by_name(prog->section_name, &btf_id);
> + err = libbpf_attach_btf_id_by_name(prog->section_name,
> + &btf_id,
> + attach_type == BPF_TRACE_RAW_TP);
[...]
