On Thu, Sep 30, 2021 at 2:00 AM Hou Tao <houtao1@xxxxxxxxxx> wrote:
>
> Program on writable tracepoint is BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
> but its attachment is the same as BPF_PROG_TYPE_RAW_TRACEPOINT.
>
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
> tools/lib/bpf/libbpf.c | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 7544d7d09160..80faa53dff35 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -8005,6 +8005,8 @@ static const struct bpf_sec_def section_defs[] = {
> SEC_DEF("tp/", TRACEPOINT, 0, SEC_NONE, attach_tp),
> SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),
> SEC_DEF("raw_tp/", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),
> + SEC_DEF("raw_tracepoint.w/", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp),
> + SEC_DEF("raw_tp.w/", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp),
> SEC_DEF("tp_btf/", TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF, attach_trace),
> SEC_DEF("fentry/", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF, attach_trace),
> SEC_DEF("fmod_ret/", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF, attach_trace),
> @@ -9762,12 +9764,21 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(const struct bpf_program *pr
>
> static struct bpf_link *attach_raw_tp(const struct bpf_program *prog, long cookie)
> {
> - const char *tp_name;
> + static const char *prefixes[] = {
> + "raw_tp/",
> + "raw_tracepoint/",
> + "raw_tp.w/",
> + "raw_tracepoint.w/",
> + };
> + size_t i;
> + const char *tp_name = NULL;
>
> - if (str_has_pfx(prog->sec_name, "raw_tp/"))
> - tp_name = prog->sec_name + sizeof("raw_tp/") - 1;
> - else
> - tp_name = prog->sec_name + sizeof("raw_tracepoint/") - 1;
> + for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
> + if (str_has_pfx(prog->sec_name, prefixes[i])) {
> + tp_name = prog->sec_name + strlen(prefixes[i]);
> + break;
> + }
> + }
Let's add if (!tp_name) check here for the future if we forget to
update this prefixes list. It's going to be a really unpleasant
SIGSEGV otherwise.
>
> return bpf_program__attach_raw_tracepoint(prog, tp_name);
> }
> --
> 2.29.2
>
