From: YiFei Zhu <zhuyifei@xxxxxxxxxx> Added a flag "--metadata" to `bpftool prog list` to dump the metadata contents. For some formatting some BTF code is put directly in the metadata dumping. Sanity checks on the map and the kind of the btf_type to make sure we are actually dumping what we are expecting. A helper jsonw_reset is added to json writer so we can reuse the same json writer without having extraneous commas. Sample output: $ bpftool prog --metadata 6: cgroup_skb name prog tag bcf7977d3b93787c gpl [...] btf_id 4 metadata: metadata_a = "foo" metadata_b = 1 $ bpftool prog --metadata --json --pretty [{ "id": 6, [...] "btf_id": 4, "metadata": { "metadata_a": "foo", "metadata_b": 1 } } ] Signed-off-by: YiFei Zhu <zhuyifei@xxxxxxxxxx> --- tools/bpf/bpftool/json_writer.c | 6 ++ tools/bpf/bpftool/json_writer.h | 3 + tools/bpf/bpftool/main.c | 10 +++ tools/bpf/bpftool/main.h | 1 + tools/bpf/bpftool/prog.c | 135 ++++++++++++++++++++++++++++++++ 5 files changed, 155 insertions(+) diff --git a/tools/bpf/bpftool/json_writer.c b/tools/bpf/bpftool/json_writer.c index 86501cd3c763..7fea83bedf48 100644 --- a/tools/bpf/bpftool/json_writer.c +++ b/tools/bpf/bpftool/json_writer.c @@ -119,6 +119,12 @@ void jsonw_pretty(json_writer_t *self, bool on) self->pretty = on; } +void jsonw_reset(json_writer_t *self) +{ + assert(self->depth == 0); + self->sep = '\0'; +} + /* Basic blocks */ static void jsonw_begin(json_writer_t *self, int c) { diff --git a/tools/bpf/bpftool/json_writer.h b/tools/bpf/bpftool/json_writer.h index 35cf1f00f96c..8ace65cdb92f 100644 --- a/tools/bpf/bpftool/json_writer.h +++ b/tools/bpf/bpftool/json_writer.h @@ -27,6 +27,9 @@ void jsonw_destroy(json_writer_t **self_p); /* Cause output to have pretty whitespace */ void jsonw_pretty(json_writer_t *self, bool on); +/* Reset separator to create new JSON */ +void jsonw_reset(json_writer_t *self); + /* Add property name */ void jsonw_name(json_writer_t *self, const char *name); diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index 4a191fcbeb82..a681d568cfa7 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -28,6 +28,7 @@ bool show_pinned; bool block_mount; bool verifier_logs; bool relaxed_maps; +bool dump_metadata; struct pinned_obj_table prog_table; struct pinned_obj_table map_table; struct pinned_obj_table link_table; @@ -351,6 +352,10 @@ static int do_batch(int argc, char **argv) return err; } +enum bpftool_longonly_opts { + OPT_METADATA = 256, +}; + int main(int argc, char **argv) { static const struct option options[] = { @@ -362,6 +367,7 @@ int main(int argc, char **argv) { "mapcompat", no_argument, NULL, 'm' }, { "nomount", no_argument, NULL, 'n' }, { "debug", no_argument, NULL, 'd' }, + { "metadata", no_argument, NULL, OPT_METADATA }, { 0 } }; int opt, ret; @@ -371,6 +377,7 @@ int main(int argc, char **argv) json_output = false; show_pinned = false; block_mount = false; + dump_metadata = false; bin_name = argv[0]; hash_init(prog_table.table); @@ -412,6 +419,9 @@ int main(int argc, char **argv) libbpf_set_print(print_all_levels); verifier_logs = true; break; + case OPT_METADATA: + dump_metadata = true; + break; default: p_err("unrecognized option '%s'", argv[optind - 1]); if (json_output) diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index c46e52137b87..8750758e9150 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -90,6 +90,7 @@ extern bool show_pids; extern bool block_mount; extern bool verifier_logs; extern bool relaxed_maps; +extern bool dump_metadata; extern struct pinned_obj_table prog_table; extern struct pinned_obj_table map_table; extern struct pinned_obj_table link_table; diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index d393eb8263a6..ee767b8d90fb 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -151,6 +151,135 @@ static void show_prog_maps(int fd, __u32 num_maps) } } +static void show_prog_metadata(int fd, __u32 num_maps) +{ + struct bpf_prog_info prog_info = {}; + struct bpf_map_info map_info = {}; + __u32 prog_info_len = sizeof(prog_info); + __u32 map_info_len = sizeof(map_info); + __u32 map_ids[num_maps]; + void *value = NULL; + struct btf *btf = NULL; + const struct btf_type *t_datasec, *t_var; + struct btf_var_secinfo *vsi; + int key = 0; + unsigned int i, vlen; + int map_fd; + int err; + + prog_info.nr_map_ids = num_maps; + prog_info.map_ids = ptr_to_u64(map_ids); + + err = bpf_obj_get_info_by_fd(fd, &prog_info, &prog_info_len); + if (err || !prog_info.nr_map_ids) + return; + + for (i = 0; i < prog_info.nr_map_ids; i++) { + map_fd = bpf_map_get_fd_by_id(map_ids[i]); + if (map_fd < 0) + return; + + err = bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len); + if (err) + goto out_close; + + if (map_info.type != BPF_MAP_TYPE_ARRAY) + goto next_map; + if (map_info.key_size != sizeof(int)) + goto next_map; + if (map_info.max_entries != 1) + goto next_map; + if (!map_info.btf_value_type_id) + goto next_map; + if (!strstr(map_info.name, ".metadata")) + goto next_map; + + goto found; + +next_map: + close(map_fd); + } + + return; + +found: + value = malloc(map_info.value_size); + if (!value) + goto out_close; + + if (bpf_map_lookup_elem(map_fd, &key, value)) + goto out_free; + + err = btf__get_from_id(map_info.btf_id, &btf); + if (err || !btf) + goto out_free; + + t_datasec = btf__type_by_id(btf, map_info.btf_value_type_id); + if (BTF_INFO_KIND(t_datasec->info) != BTF_KIND_DATASEC) + goto out_free; + + vlen = BTF_INFO_VLEN(t_datasec->info); + vsi = (struct btf_var_secinfo *)(t_datasec + 1); + + if (json_output) { + struct btf_dumper d = { + .btf = btf, + .jw = json_wtr, + .is_plain_text = false, + }; + + jsonw_name(json_wtr, "metadata"); + + jsonw_start_object(json_wtr); + for (i = 0; i < vlen; i++) { + t_var = btf__type_by_id(btf, vsi[i].type); + + if (BTF_INFO_KIND(t_var->info) != BTF_KIND_VAR) + continue; + + jsonw_name(json_wtr, btf__name_by_offset(btf, t_var->name_off)); + err = btf_dumper_type(&d, t_var->type, value + vsi[i].offset); + if (err) + break; + } + jsonw_end_object(json_wtr); + } else { + json_writer_t *btf_wtr = jsonw_new(stdout); + struct btf_dumper d = { + .btf = btf, + .jw = btf_wtr, + .is_plain_text = true, + }; + if (!btf_wtr) + goto out_free; + + printf("\tmetadata:"); + + for (i = 0; i < vlen; i++) { + t_var = btf__type_by_id(btf, vsi[i].type); + + if (BTF_INFO_KIND(t_var->info) != BTF_KIND_VAR) + continue; + + printf("\n\t\t%s = ", btf__name_by_offset(btf, t_var->name_off)); + + jsonw_reset(btf_wtr); + err = btf_dumper_type(&d, t_var->type, value + vsi[i].offset); + if (err) + break; + } + + jsonw_destroy(&btf_wtr); + } + +out_free: + btf__free(btf); + free(value); + +out_close: + close(map_fd); +} + static void print_prog_header_json(struct bpf_prog_info *info) { jsonw_uint_field(json_wtr, "id", info->id); @@ -228,6 +357,9 @@ static void print_prog_json(struct bpf_prog_info *info, int fd) emit_obj_refs_json(&refs_table, info->id, json_wtr); + if (dump_metadata) + show_prog_metadata(fd, info->nr_map_ids); + jsonw_end_object(json_wtr); } @@ -297,6 +429,9 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd) emit_obj_refs_plain(&refs_table, info->id, "\n\tpids "); printf("\n"); + + if (dump_metadata) + show_prog_metadata(fd, info->nr_map_ids); } static int show_prog(int fd) -- 2.28.0