libbpf: add tracepoint attach API (f6de59c1) · Commits · 戴 / test

tools/lib/bpf/libbpf.c

+79 −0

Original line number	Diff line number	Diff line
		@@ -4190,6 +4190,85 @@ struct bpf_link bpf_program__attach_uprobe(struct bpf_program prog,
		return link;
		}

		static int determine_tracepoint_id(const char *tp_category,
		const char *tp_name)
		{
		char file[PATH_MAX];
		int ret;

		ret = snprintf(file, sizeof(file),
		"/sys/kernel/debug/tracing/events/%s/%s/id",
		tp_category, tp_name);
		if (ret < 0)
		return -errno;
		if (ret >= sizeof(file)) {
		pr_debug("tracepoint %s/%s path is too long\n",
		tp_category, tp_name);
		return -E2BIG;
		}
		return parse_uint_from_file(file, "%d\n");
		}

		static int perf_event_open_tracepoint(const char *tp_category,
		const char *tp_name)
		{
		struct perf_event_attr attr = {};
		char errmsg[STRERR_BUFSIZE];
		int tp_id, pfd, err;

		tp_id = determine_tracepoint_id(tp_category, tp_name);
		if (tp_id < 0) {
		pr_warning("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
		tp_category, tp_name,
		libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
		return tp_id;
		}

		attr.type = PERF_TYPE_TRACEPOINT;
		attr.size = sizeof(attr);
		attr.config = tp_id;

		pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid /, 0 / cpu */,
		-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
		if (pfd < 0) {
		err = -errno;
		pr_warning("tracepoint '%s/%s' perf_event_open() failed: %s\n",
		tp_category, tp_name,
		libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
		return err;
		}
		return pfd;
		}

		struct bpf_link bpf_program__attach_tracepoint(struct bpf_program prog,
		const char *tp_category,
		const char *tp_name)
		{
		char errmsg[STRERR_BUFSIZE];
		struct bpf_link *link;
		int pfd, err;

		pfd = perf_event_open_tracepoint(tp_category, tp_name);
		if (pfd < 0) {
		pr_warning("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
		bpf_program__title(prog, false),
		tp_category, tp_name,
		libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
		return ERR_PTR(pfd);
		}
		link = bpf_program__attach_perf_event(prog, pfd);
		if (IS_ERR(link)) {
		close(pfd);
		err = PTR_ERR(link);
		pr_warning("program '%s': failed to attach to tracepoint '%s/%s': %s\n",
		bpf_program__title(prog, false),
		tp_category, tp_name,
		libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
		return link;
		}
		return 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,

tools/lib/bpf/libbpf.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -178,6 +178,10 @@ LIBBPF_API struct bpf_link *
		bpf_program__attach_uprobe(struct bpf_program *prog, bool retprobe,
		pid_t pid, const char *binary_path,
		size_t func_offset);
		LIBBPF_API struct bpf_link *
		bpf_program__attach_tracepoint(struct bpf_program *prog,
		const char *tp_category,
		const char *tp_name);

		struct bpf_insn;

tools/lib/bpf/libbpf.map

+1 −0

Original line number	Diff line number	Diff line
		@@ -171,6 +171,7 @@ LIBBPF_0.0.4 {
		bpf_object__load_xattr;
		bpf_program__attach_kprobe;
		bpf_program__attach_perf_event;
		bpf_program__attach_tracepoint;
		bpf_program__attach_uprobe;
		btf_dump__dump_type;
		btf_dump__free;

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