[RFC,bpf-next,13/17] libbpf: Add support to create tracing multi link

Message ID	20220808140626.422731-14-jolsa@kernel.org (mailing list archive)
State	RFC
Delegated to:	BPF
Headers	show Return-Path: <bpf-owner@kernel.org> From: Jiri Olsa <jolsa@kernel.org> To: Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>, John Fastabend <john.fastabend@gmail.com>, KP Singh <kpsingh@chromium.org>, Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com> Subject: [RFC PATCH bpf-next 13/17] libbpf: Add support to create tracing multi link Date: Mon, 8 Aug 2022 16:06:22 +0200 Message-Id: <20220808140626.422731-14-jolsa@kernel.org> In-Reply-To: <20220808140626.422731-1-jolsa@kernel.org> References: <20220808140626.422731-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	bpf: Add tracing multi link \| expand [RFC,bpf-next,00/17] bpf: Add tracing multi link [RFC,bpf-next,01/17] bpf: Link shimlink directly in trampoline [RFC,bpf-next,02/17] bpf: Replace bpf_tramp_links with bpf_tramp_progs [RFC,bpf-next,03/17] bpf: Store trampoline progs in arrays [RFC,bpf-next,04/17] bpf: Add multi tracing attach types [RFC,bpf-next,05/17] bpf: Add bpf_tramp_id object [RFC,bpf-next,06/17] bpf: Pass image struct to reg/unreg/modify fentry functions [RFC,bpf-next,07/17] bpf: Add support to postpone trampoline update [RFC,bpf-next,08/17] bpf: Factor bpf_trampoline_lookup function [RFC,bpf-next,09/17] bpf: Factor bpf_trampoline_put function [RFC,bpf-next,10/17] bpf: Add support to attach program to multiple trampolines [RFC,bpf-next,11/17] bpf: Add support to create tracing multi link [RFC,bpf-next,12/17] libbpf: Add btf__find_by_glob_kind function [RFC,bpf-next,13/17] libbpf: Add support to create tracing multi link [RFC,bpf-next,14/17] selftests/bpf: Add fentry tracing multi func test [RFC,bpf-next,15/17] selftests/bpf: Add fexit tracing multi func test [RFC,bpf-next,16/17] selftests/bpf: Add fentry/fexit tracing multi func test [RFC,bpf-next,17/17] selftests/bpf: Add mixed tracing multi func test

Context	Check	Description
netdev/tree_selection	success	Clearly marked for bpf-next, async
netdev/apply	fail	Patch does not apply to bpf-next
bpf/vmtest-bpf-next-PR	fail	merge-conflict

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index efcc06dafbd9..06e6666ee90e 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -713,6 +713,13 @@ 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_MULTI: + case BPF_TRACE_FEXIT_MULTI: + attr.link_create.tracing_multi.btf_ids = (__u64) OPTS_GET(opts, tracing_multi.btf_ids, 0); + attr.link_create.tracing_multi.btf_ids_cnt = OPTS_GET(opts, tracing_multi.btf_ids_cnt, 0); + if (!OPTS_ZEROED(opts, tracing_multi)) + return libbpf_err(-EINVAL); + break; case BPF_TRACE_FENTRY: case BPF_TRACE_FEXIT: case BPF_MODIFY_RETURN: diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 9c50beabdd14..71676228f032 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -321,6 +321,10 @@ struct bpf_link_create_opts { struct { __u64 cookie; } tracing; + struct { + __u32 *btf_ids; + __u32 btf_ids_cnt; + } tracing_multi; }; size_t :0; }; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0952eac92eab..209a42bed165 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -116,6 +116,8 @@ static const char * const attach_type_name[] = { [BPF_SK_REUSEPORT_SELECT_OR_MIGRATE] = "sk_reuseport_select_or_migrate", [BPF_PERF_EVENT] = "perf_event", [BPF_TRACE_KPROBE_MULTI] = "trace_kprobe_multi", + [BPF_TRACE_FENTRY_MULTI] = "trace_fentry_multi", + [BPF_TRACE_FEXIT_MULTI] = "trace_fexit_multi", }; static const char * const link_type_name[] = { @@ -129,6 +131,7 @@ static const char * const link_type_name[] = { [BPF_LINK_TYPE_PERF_EVENT] = "perf_event", [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_LINK_TYPE_TRACING_MULTI] = "tracing_multi", }; static const char * const map_type_name[] = { @@ -8445,6 +8448,7 @@ 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_tracing_multi(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), @@ -8477,6 +8481,8 @@ static const struct bpf_sec_def section_defs[] = { SEC_DEF("fentry.s+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), SEC_DEF("fmod_ret.s+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), SEC_DEF("fexit.s+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("fentry.multi/", TRACING, BPF_TRACE_FENTRY_MULTI, 0, attach_tracing_multi), + SEC_DEF("fexit.multi/", TRACING, BPF_TRACE_FEXIT_MULTI, 0, attach_tracing_multi), SEC_DEF("freplace+", EXT, 0, SEC_ATTACH_BTF, attach_trace), SEC_DEF("lsm+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm), SEC_DEF("lsm.s+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm), @@ -10374,6 +10380,89 @@ static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, stru return libbpf_get_error(*link); } +struct bpf_link * +bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char *pattern, + const struct bpf_tracing_multi_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, lopts); + __u32 *btf_ids, cnt, *free_ids = NULL; + char errmsg[STRERR_BUFSIZE]; + int prog_fd, link_fd, err; + struct bpf_link *link; + + btf_ids = OPTS_GET(opts, btf_ids, false); + cnt = OPTS_GET(opts, cnt, false); + + if (!pattern && !btf_ids && !cnt) + return libbpf_err_ptr(-EINVAL); + if (pattern && (btf_ids || cnt)) + return libbpf_err_ptr(-EINVAL); + + if (pattern) { + err = bpf_object__load_vmlinux_btf(prog->obj, true); + if (err) + return libbpf_err_ptr(err); + + cnt = btf__find_by_glob_kind(prog->obj->btf_vmlinux, BTF_KIND_FUNC, + pattern, NULL, &btf_ids); + if (cnt <= 0) + return libbpf_err_ptr(-EINVAL); + free_ids = btf_ids; + } + + lopts.tracing_multi.btf_ids = btf_ids; + lopts.tracing_multi.btf_ids_cnt = cnt; + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_err_ptr(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + prog_fd = bpf_program__fd(prog); + link_fd = bpf_link_create(prog_fd, 0, prog->expected_attach_type, &lopts); + if (link_fd < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach: %s\n", + prog->name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto error; + } + link->fd = link_fd; + free(free_ids); + return link; +error: + free(link); + free(free_ids); + return libbpf_err_ptr(err); +} + +static int attach_tracing_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + const char *spec; + char *pattern; + bool is_fexit; + int n; + + /* no auto-attach for SEC("fentry.multi") and SEC("fexit.multi") */ + if (strcmp(prog->sec_name, "fentry.multi") == 0 || + strcmp(prog->sec_name, "fexit.multi") == 0) + return 0; + + is_fexit = str_has_pfx(prog->sec_name, "fexit.multi/"); + if (is_fexit) + spec = prog->sec_name + sizeof("fexit.multi/") - 1; + else + spec = prog->sec_name + sizeof("fentry.multi/") - 1; + + n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern); + if (n < 1) { + pr_warn("tracing multi pattern is invalid: %s\n", pattern); + return -EINVAL; + } + + *link = bpf_program__attach_tracing_multi(prog, pattern, NULL); + return libbpf_get_error(*link); +} + static void gen_uprobe_legacy_event_name(char *buf, size_t buf_sz, const char *binary_path, uint64_t offset) { diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 61493c4cddac..07992d8ee06c 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -503,6 +503,20 @@ bpf_program__attach_ksyscall(const struct bpf_program *prog, const char *syscall_name, const struct bpf_ksyscall_opts *opts); +struct bpf_tracing_multi_opts { + /* size of this struct, for forward/backward compatibility */ + size_t sz; + __u32 *btf_ids; + size_t cnt; + size_t :0; +}; + +#define bpf_kprobe_multi_opts__last_field retprobe + +LIBBPF_API struct bpf_link * +bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char *pattern, + const struct bpf_tracing_multi_opts *opts); + struct bpf_uprobe_opts { /* size of this struct, for forward/backward compatiblity */ size_t sz; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 119e6e1ea7f1..2168516a75a5 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -358,6 +358,7 @@ LIBBPF_1.0.0 { bpf_obj_get_opts; bpf_prog_query_opts; bpf_program__attach_ksyscall; + bpf_program__attach_tracing_multi; btf__add_enum64; btf__add_enum64_value; libbpf_bpf_attach_type_str;

[RFC,bpf-next,13/17] libbpf: Add support to create tracing multi link

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