On Sat, May 14, 2022 at 7:35 PM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote:
>
> Add support to attach RSTAT_FLUSH programs.
>
> Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
> ---
> tools/lib/bpf/bpf.c | 1 -
> tools/lib/bpf/libbpf.c | 40 ++++++++++++++++++++++++++++++++++++++++
> tools/lib/bpf/libbpf.h | 3 +++
> tools/lib/bpf/libbpf.map | 1 +
> 4 files changed, 44 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 5660268e103f..9e3cb0d1eb99 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -870,7 +870,6 @@ int bpf_link_create(int prog_fd, int target_fd,
> attr.link_create.tracing.cookie = OPTS_GET(opts, tracing.cookie, 0);
> if (!OPTS_ZEROED(opts, tracing))
> return libbpf_err(-EINVAL);
> - break;
This is a mistake, a remnant of RFC V1. Will remove it in the next version.
> default:
> if (!OPTS_ZEROED(opts, flags))
> return libbpf_err(-EINVAL);
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 4867a930628b..b7fc64ebf8dd 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -8998,6 +8998,7 @@ static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_
> static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> +static int attach_rstat(const struct bpf_program *prog, long cookie, struct bpf_link **link);
>
> static const struct bpf_sec_def section_defs[] = {
> SEC_DEF("socket", SOCKET_FILTER, 0, SEC_NONE | SEC_SLOPPY_PFX),
> @@ -9078,6 +9079,7 @@ static const struct bpf_sec_def section_defs[] = {
> SEC_DEF("cgroup/setsockopt", CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
> SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE),
> SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
> + SEC_DEF("rstat/flush", RSTAT_FLUSH, 0, SEC_NONE, attach_rstat),
> };
>
> static size_t custom_sec_def_cnt;
> @@ -11784,6 +11786,44 @@ static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_l
> return libbpf_get_error(*link);
> }
>
> +struct bpf_link *bpf_program__attach_rstat(const struct bpf_program *prog)
> +{
> + struct bpf_link *link = NULL;
> + char errmsg[STRERR_BUFSIZE];
> + int err, prog_fd, link_fd;
> +
> + prog_fd = bpf_program__fd(prog);
> + if (prog_fd < 0) {
> + pr_warn("prog '%s': can't attach before loaded\n", prog->name);
> + return libbpf_err_ptr(-EINVAL);
> + }
> +
> + link = calloc(1, sizeof(*link));
> + if (!link)
> + return libbpf_err_ptr(-ENOMEM);
> + link->detach = &bpf_link__detach_fd;
> +
> + /* rstat flushers are currently the only supported rstat programs */
> + link_fd = bpf_link_create(prog_fd, 0, BPF_RSTAT_FLUSH, NULL);
> + if (link_fd < 0) {
> + err = -errno;
> + pr_warn("prog '%s': failed to attach: %s\n",
> + prog->name, libbpf_strerror_r(err, errmsg,
> + sizeof(errmsg)));
> + free(link);
> + return libbpf_err_ptr(err);
> + }
> +
> + link->fd = link_fd;
> + return link;
> +}
> +
> +static int attach_rstat(const struct bpf_program *prog, long cookie, struct bpf_link **link)
> +{
> + *link = bpf_program__attach_rstat(prog);
> + return libbpf_get_error(*link);
> +}
> +
> struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
> {
> struct bpf_link *link = NULL;
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 21984dcd6dbe..f8b6827d5550 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -662,6 +662,9 @@ LIBBPF_API struct bpf_link *
> bpf_program__attach_iter(const struct bpf_program *prog,
> const struct bpf_iter_attach_opts *opts);
>
> +LIBBPF_API struct bpf_link *
> +bpf_program__attach_rstat(const struct bpf_program *prog);
> +
> /*
> * Libbpf allows callers to adjust BPF programs before being loaded
> * into kernel. One program in an object file can be transformed into
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 008da8db1d94..f945c6265cb5 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -449,6 +449,7 @@ LIBBPF_0.8.0 {
> bpf_program__attach_kprobe_multi_opts;
> bpf_program__attach_trace_opts;
> bpf_program__attach_usdt;
> + bpf_program__attach_rstat;
> bpf_program__set_insns;
> libbpf_register_prog_handler;
> libbpf_unregister_prog_handler;
> --
> 2.36.0.550.gb090851708-goog
>
