From 84bf5e1f4f174fc4f06bc747dafa1a7cfa4e9a67 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 1 Jul 2019 16:59:00 -0700 Subject: [PATCH] libbpf: add raw tracepoint attach API Add a wrapper utilizing bpf_link "infrastructure" to allow attaching BPF programs to raw tracepoints. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Reviewed-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 39 +++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 3 +++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 43 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 85174fcd99e0..981fb5c3c6c9 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4269,6 +4269,45 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog, return link; } +static int bpf_link__destroy_fd(struct bpf_link *link) +{ + struct bpf_link_fd *l = (void *)link; + + return close(l->fd); +} + +struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, + const char *tp_name) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link_fd *link; + int prog_fd, pfd; + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warning("program '%s': can't attach before loaded\n", + bpf_program__title(prog, false)); + return ERR_PTR(-EINVAL); + } + + link = malloc(sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->link.destroy = &bpf_link__destroy_fd; + + pfd = bpf_raw_tracepoint_open(tp_name, prog_fd); + if (pfd < 0) { + pfd = -errno; + free(link); + pr_warning("program '%s': failed to attach to raw tracepoint '%s': %s\n", + bpf_program__title(prog, false), tp_name, + libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + return ERR_PTR(pfd); + } + link->fd = pfd; + return (struct bpf_link *)link; +} + enum bpf_perf_event_ret bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, void **copy_mem, size_t *copy_size, diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 60611f4b4e1d..f55933784f95 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -182,6 +182,9 @@ LIBBPF_API struct bpf_link * bpf_program__attach_tracepoint(struct bpf_program *prog, const char *tp_category, const char *tp_name); +LIBBPF_API struct bpf_link * +bpf_program__attach_raw_tracepoint(struct bpf_program *prog, + const char *tp_name); struct bpf_insn; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 3c618b75ef65..e6b7d4edbc93 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -171,6 +171,7 @@ LIBBPF_0.0.4 { bpf_object__load_xattr; bpf_program__attach_kprobe; bpf_program__attach_perf_event; + bpf_program__attach_raw_tracepoint; bpf_program__attach_tracepoint; bpf_program__attach_uprobe; btf_dump__dump_type; -- 2.30.2