From c09add2fbc5aece00a5b54a48ce39fd4e3284d87 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sat, 9 May 2020 10:59:17 -0700 Subject: tools/libbpf: Add bpf_iter support Two new libbpf APIs are added to support bpf_iter: - bpf_program__attach_iter Given a bpf program and additional parameters, which is none now, returns a bpf_link. - bpf_iter_create syscall level API to create a bpf iterator. The macro BPF_SEQ_PRINTF are also introduced. The format looks like: BPF_SEQ_PRINTF(seq, "task id %d\n", pid); This macro can help bpf program writers with nicer bpf_seq_printf syntax similar to the kernel one. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200509175917.2476936-1-yhs@fb.com --- tools/lib/bpf/bpf.c | 10 +++++++++ tools/lib/bpf/bpf.h | 2 ++ tools/lib/bpf/bpf_tracing.h | 16 ++++++++++++++ tools/lib/bpf/libbpf.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 9 ++++++++ tools/lib/bpf/libbpf.map | 2 ++ 6 files changed, 91 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 43322f0d6c7f..a7329b671c41 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -619,6 +619,16 @@ int bpf_link_update(int link_fd, int new_prog_fd, return sys_bpf(BPF_LINK_UPDATE, &attr, sizeof(attr)); } +int bpf_iter_create(int link_fd) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.iter_create.link_fd = link_fd; + + return sys_bpf(BPF_ITER_CREATE, &attr, sizeof(attr)); +} + int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags, __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt) { diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 1901b2777854..1b6015b21ba8 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -187,6 +187,8 @@ struct bpf_link_update_opts { LIBBPF_API int bpf_link_update(int link_fd, int new_prog_fd, const struct bpf_link_update_opts *opts); +LIBBPF_API int bpf_iter_create(int link_fd); + struct bpf_prog_test_run_attr { int prog_fd; int repeat; diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index f3f3c3fb98cb..cf97d07692b4 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -413,4 +413,20 @@ typeof(name(0)) name(struct pt_regs *ctx) \ } \ static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args) +/* + * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values + * in a structure. + */ +#define BPF_SEQ_PRINTF(seq, fmt, args...) \ + ({ \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + static const char ___fmt[] = fmt; \ + unsigned long long ___param[] = { args }; \ + _Pragma("GCC diagnostic pop") \ + int ___ret = bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \ + ___param, sizeof(___param)); \ + ___ret; \ + }) + #endif diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 977add1b73e2..6c2f46908f4d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6586,6 +6586,8 @@ static struct bpf_link *attach_trace(const struct bpf_sec_def *sec, struct bpf_program *prog); static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec, struct bpf_program *prog); +static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, + struct bpf_program *prog); static const struct bpf_sec_def section_defs[] = { BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER), @@ -6629,6 +6631,10 @@ static const struct bpf_sec_def section_defs[] = { .is_attach_btf = true, .expected_attach_type = BPF_LSM_MAC, .attach_fn = attach_lsm), + SEC_DEF("iter/", TRACING, + .expected_attach_type = BPF_TRACE_ITER, + .is_attach_btf = true, + .attach_fn = attach_iter), BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP), BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT), BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN), @@ -6891,6 +6897,7 @@ invalid_prog: #define BTF_TRACE_PREFIX "btf_trace_" #define BTF_LSM_PREFIX "bpf_lsm_" +#define BTF_ITER_PREFIX "__bpf_iter__" #define BTF_MAX_NAME_SIZE 128 static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, @@ -6921,6 +6928,9 @@ static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name, else if (attach_type == BPF_LSM_MAC) err = find_btf_by_prefix_kind(btf, BTF_LSM_PREFIX, name, BTF_KIND_FUNC); + else if (attach_type == BPF_TRACE_ITER) + err = find_btf_by_prefix_kind(btf, BTF_ITER_PREFIX, name, + BTF_KIND_FUNC); else err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC); @@ -7848,6 +7858,12 @@ static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec, return bpf_program__attach_lsm(prog); } +static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, + struct bpf_program *prog) +{ + return bpf_program__attach_iter(prog, NULL); +} + struct bpf_link * bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) { @@ -7882,6 +7898,42 @@ bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) return link; } +struct bpf_link * +bpf_program__attach_iter(struct bpf_program *prog, + const struct bpf_iter_attach_opts *opts) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, link_fd; + + if (!OPTS_VALID(opts, bpf_iter_attach_opts)) + return ERR_PTR(-EINVAL); + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("program '%s': can't attach before loaded\n", + bpf_program__title(prog, false)); + return ERR_PTR(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_ITER, NULL); + if (link_fd < 0) { + link_fd = -errno; + free(link); + pr_warn("program '%s': failed to attach to iterator: %s\n", + bpf_program__title(prog, false), + libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); + return ERR_PTR(link_fd); + } + link->fd = link_fd; + return link; +} + struct bpf_link *bpf_program__attach(struct bpf_program *prog) { const struct bpf_sec_def *sec_def; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index f1dacecb1619..8ea69558f0a8 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -258,6 +258,15 @@ struct bpf_map; LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map); +struct bpf_iter_attach_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ +}; +#define bpf_iter_attach_opts__last_field sz + +LIBBPF_API struct bpf_link * +bpf_program__attach_iter(struct bpf_program *prog, + const struct bpf_iter_attach_opts *opts); + struct bpf_insn; /* diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index e03bd4db827e..0133d469d30b 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -258,6 +258,8 @@ LIBBPF_0.0.8 { LIBBPF_0.0.9 { global: bpf_enable_stats; + bpf_iter_create; bpf_link_get_fd_by_id; bpf_link_get_next_id; + bpf_program__attach_iter; } LIBBPF_0.0.8; -- cgit v1.2.3