Re: [PATCH 07/10] libbpf: Add bpf_link_create support for multi kprobes

[Andrii Nakryiko]

On Tue, Feb 22, 2022 at 9:07 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding new kprobe_multi struct to bpf_link_create_opts object
> to pass multiple kprobe data to link_create attr uapi.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  tools/lib/bpf/bpf.c | 7 +++++++
>  tools/lib/bpf/bpf.h | 9 ++++++++-
>  2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 418b259166f8..5e180def2cef 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -853,6 +853,13 @@ int bpf_link_create(int prog_fd, int target_fd,
>                 if (!OPTS_ZEROED(opts, perf_event))
>                         return libbpf_err(-EINVAL);
>                 break;
> +       case BPF_TRACE_KPROBE_MULTI:
> +               attr.link_create.kprobe_multi.syms = OPTS_GET(opts, kprobe_multi.syms, 0);
> +               attr.link_create.kprobe_multi.addrs = OPTS_GET(opts, kprobe_multi.addrs, 0);
> +               attr.link_create.kprobe_multi.cookies = OPTS_GET(opts, kprobe_multi.cookies, 0);
> +               attr.link_create.kprobe_multi.cnt = OPTS_GET(opts, kprobe_multi.cnt, 0);
> +               attr.link_create.kprobe_multi.flags = OPTS_GET(opts, kprobe_multi.flags, 0);
> +               break;
>         default:
>                 if (!OPTS_ZEROED(opts, flags))
>                         return libbpf_err(-EINVAL);
> diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
> index 16b21757b8bf..bd285a8f3420 100644
> --- a/tools/lib/bpf/bpf.h
> +++ b/tools/lib/bpf/bpf.h
> @@ -413,10 +413,17 @@ struct bpf_link_create_opts {
>                 struct {
>                         __u64 bpf_cookie;
>                 } perf_event;
> +               struct {
> +                       __u64 syms;
> +                       __u64 addrs;
> +                       __u64 cookies;

hm, I think we can and should use proper types here, no?

const char **syms;
const void **addrs;
const __u64 *cookies;

?




> +                       __u32 cnt;
> +                       __u32 flags;
> +               } kprobe_multi;
>         };
>         size_t :0;
>  };
> -#define bpf_link_create_opts__last_field perf_event
> +#define bpf_link_create_opts__last_field kprobe_multi.flags
>
>  LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
>                                enum bpf_attach_type attach_type,
> --
> 2.35.1
>