From 129b9c5ee2c18c3e36ec289140b5149f301118d1 Mon Sep 17 00:00:00 2001 From: Kui-Feng Lee Date: Tue, 10 May 2022 13:59:22 -0700 Subject: libbpf: Assign cookies to links in libbpf. Add a cookie field to the attributes of bpf_link_create(). Add bpf_program__attach_trace_opts() to attach a cookie to a link. Signed-off-by: Kui-Feng Lee Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220510205923.3206889-5-kuifeng@fb.com --- tools/lib/bpf/bpf.c | 8 ++++++++ tools/lib/bpf/bpf.h | 3 +++ tools/lib/bpf/libbpf.c | 20 ++++++++++++++++---- tools/lib/bpf/libbpf.h | 12 ++++++++++++ tools/lib/bpf/libbpf.map | 1 + 5 files changed, 40 insertions(+), 4 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index a9d292c106c2..5660268e103f 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -863,6 +863,14 @@ int bpf_link_create(int prog_fd, int target_fd, if (!OPTS_ZEROED(opts, kprobe_multi)) return libbpf_err(-EINVAL); break; + case BPF_TRACE_FENTRY: + case BPF_TRACE_FEXIT: + case BPF_MODIFY_RETURN: + case BPF_LSM_MAC: + attr.link_create.tracing.cookie = OPTS_GET(opts, tracing.cookie, 0); + if (!OPTS_ZEROED(opts, tracing)) + return libbpf_err(-EINVAL); + 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 f4b4afb6d4ba..34af2232928c 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -420,6 +420,9 @@ struct bpf_link_create_opts { const unsigned long *addrs; const __u64 *cookies; } kprobe_multi; + struct { + __u64 cookie; + } tracing; }; size_t :0; }; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 15117b9a4d1e..a5904c0ac794 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11568,12 +11568,17 @@ static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf } /* Common logic for all BPF program types that attach to a btf_id */ -static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *prog) +static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *prog, + const struct bpf_trace_opts *opts) { + LIBBPF_OPTS(bpf_link_create_opts, link_opts); char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int prog_fd, pfd; + if (!OPTS_VALID(opts, bpf_trace_opts)) + return libbpf_err_ptr(-EINVAL); + prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); @@ -11586,7 +11591,8 @@ static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *pro link->detach = &bpf_link__detach_fd; /* libbpf is smart enough to redirect to BPF_RAW_TRACEPOINT_OPEN on old kernels */ - pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), NULL); + link_opts.tracing.cookie = OPTS_GET(opts, cookie, 0); + pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), &link_opts); if (pfd < 0) { pfd = -errno; free(link); @@ -11600,12 +11606,18 @@ static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *pro struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog) { - return bpf_program__attach_btf_id(prog); + return bpf_program__attach_btf_id(prog, NULL); +} + +struct bpf_link *bpf_program__attach_trace_opts(const struct bpf_program *prog, + const struct bpf_trace_opts *opts) +{ + return bpf_program__attach_btf_id(prog, opts); } struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog) { - return bpf_program__attach_btf_id(prog); + return bpf_program__attach_btf_id(prog, NULL); } static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link) diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 114b1f6f73a5..a1fb91810378 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -603,8 +603,20 @@ bpf_program__attach_tracepoint_opts(const struct bpf_program *prog, LIBBPF_API struct bpf_link * bpf_program__attach_raw_tracepoint(const struct bpf_program *prog, const char *tp_name); + +struct bpf_trace_opts { + /* size of this struct, for forward/backward compatibility */ + size_t sz; + /* custom user-provided value fetchable through bpf_get_attach_cookie() */ + __u64 cookie; +}; +#define bpf_trace_opts__last_field cookie + LIBBPF_API struct bpf_link * bpf_program__attach_trace(const struct bpf_program *prog); +LIBBPF_API struct bpf_link * +bpf_program__attach_trace_opts(const struct bpf_program *prog, const struct bpf_trace_opts *opts); + LIBBPF_API struct bpf_link * bpf_program__attach_lsm(const struct bpf_program *prog); LIBBPF_API struct bpf_link * diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index b5bc84039407..80819e26a976 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -447,6 +447,7 @@ LIBBPF_0.8.0 { bpf_object__destroy_subskeleton; bpf_object__open_subskeleton; bpf_program__attach_kprobe_multi_opts; + bpf_program__attach_trace_opts; bpf_program__attach_usdt; libbpf_register_prog_handler; libbpf_unregister_prog_handler; -- cgit v1.2.3