Provide a way to dump BTF metadata info via bpftool; this consists of BTF size, header fields and layout info (if available); for example $ bpftool btf dump file vmlinux format meta size 6516862 magic 0xeb9f version 1 flags 0x0 hdr_len 32 type_len 3929096 type_off 0 str_len 2587654 str_off 3929176 layout_len 80 layout_off 3929096 kind 0 UNKNOWN info_sz 0 elem_sz 0 flags 0 kind 1 INT info_sz 4 elem_sz 0 flags 0 kind 2 PTR info_sz 0 elem_sz 0 flags 0 kind 3 ARRAY info_sz 12 elem_sz 0 flags 0 kind 4 STRUCT info_sz 0 elem_sz 12 flags 0 kind 5 UNION info_sz 0 elem_sz 12 flags 0 kind 6 ENUM info_sz 0 elem_sz 8 flags 0 kind 7 FWD info_sz 0 elem_sz 0 flags 0 kind 8 TYPEDEF info_sz 0 elem_sz 0 flags 0 kind 9 VOLATILE info_sz 0 elem_sz 0 flags 0 kind 10 CONST info_sz 0 elem_sz 0 flags 0 kind 11 RESTRICT info_sz 0 elem_sz 0 flags 0 kind 12 FUNC info_sz 0 elem_sz 0 flags 0 kind 13 FUNC_PROTO info_sz 0 elem_sz 8 flags 0 kind 14 VAR info_sz 4 elem_sz 0 flags 0 kind 15 DATASEC info_sz 0 elem_sz 12 flags 0 kind 16 FLOAT info_sz 0 elem_sz 0 flags 0 kind 17 DECL_TAG info_sz 4 elem_sz 0 flags 0 kind 18 TYPE_TAG info_sz 0 elem_sz 0 flags 0 kind 19 ENUM64 info_sz 0 elem_sz 12 flags 0 JSON output is also supported: $ bpftool -p btf dump file /var/tmp/vmlinux.kind_layout format meta { "size": 6516862, "header": { "magic": 60319, "version": 1, "flags": 0, "hdr_len": 32, "type_len": 3929096, "type_off": 0, "str_len": 2587654, "str_off": 3929176, "layout_len": 80, "layout_offset": 3929096 }, "layouts": [{ "kind": 0, "name": "UNKNOWN", "info_sz": 0, "elem_sz": 0, "flags": 0 },{ "kind": 1, "name": "INT", "info_sz": 4, "elem_sz": 0, "flags": 0 },{ "kind": 2, "name": "PTR", "info_sz": 0, "elem_sz": 0, "flags": 0 },{ ... Signed-off-by: Alan Maguire --- tools/bpf/bpftool/bash-completion/bpftool | 2 +- tools/bpf/bpftool/btf.c | 94 ++++++++++++++++++++++- 2 files changed, 92 insertions(+), 4 deletions(-) diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index a28f0cc522e4..d49d6a70cb74 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -950,7 +950,7 @@ _bpftool() return 0 ;; format) - COMPREPLY=( $( compgen -W "c raw" -- "$cur" ) ) + COMPREPLY=( $( compgen -W "c raw meta" -- "$cur" ) ) ;; root_id) return 0; diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 946612029dee..02f6ca4b3a51 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -835,6 +835,90 @@ static int dump_btf_c(const struct btf *btf, return err; } +static int dump_btf_meta(const struct btf *btf) +{ + __u32 data_sz, i, nr_kinds = 0; + const struct btf_header *hdr; + const struct btf_layout *l; + const void *data; + + data = btf__raw_data(btf, &data_sz); + if (!data) + return -ENOMEM; + hdr = data; + if (json_output) { + jsonw_start_object(json_wtr); /* metadata object */ + jsonw_uint_field(json_wtr, "size", data_sz); + jsonw_name(json_wtr, "header"); + jsonw_start_object(json_wtr); /* header object */ + jsonw_uint_field(json_wtr, "magic", hdr->magic); + jsonw_uint_field(json_wtr, "version", hdr->version); + jsonw_uint_field(json_wtr, "flags", hdr->flags); + jsonw_uint_field(json_wtr, "hdr_len", hdr->hdr_len); + jsonw_uint_field(json_wtr, "type_len", hdr->type_len); + jsonw_uint_field(json_wtr, "type_off", hdr->type_off); + jsonw_uint_field(json_wtr, "str_len", hdr->str_len); + jsonw_uint_field(json_wtr, "str_off", hdr->str_off); + } else { + printf("size %-10u\n", data_sz); + printf("magic 0x%-10x\nversion %-10d\nflags 0x%-10x\nhdr_len %-10u\n", + hdr->magic, hdr->version, hdr->flags, hdr->hdr_len); + printf("type_len %-10u\ntype_off %-10u\n", hdr->type_len, hdr->type_off); + printf("str_len %-10u\nstr_off %-10u\n", hdr->str_len, hdr->str_off); + } + + if (hdr->hdr_len < sizeof(struct btf_header) || data_sz <= hdr->hdr_len) { + if (json_output) { + jsonw_end_object(json_wtr); /* end header object */ + jsonw_end_object(json_wtr); /* end metadata object */ + } + return 0; + } + + data_sz -= hdr->hdr_len; + + if (hdr->layout_len > 0 && hdr->layout_off > 0) { + if ((long long)hdr->layout_off + hdr->layout_len <= data_sz) { + l = (void *)hdr + hdr->hdr_len + hdr->layout_off; + nr_kinds = hdr->layout_len / sizeof(*l); + } + } + if (json_output) { + jsonw_uint_field(json_wtr, "layout_len", hdr->layout_len); + jsonw_uint_field(json_wtr, "layout_offset", hdr->layout_off); + jsonw_end_object(json_wtr); /* end header object */ + + if (nr_kinds > 0) { + jsonw_name(json_wtr, "layouts"); + jsonw_start_array(json_wtr); + for (i = 0; i < nr_kinds; i++) { + jsonw_start_object(json_wtr); + jsonw_uint_field(json_wtr, "kind", i); + if (i < NR_BTF_KINDS) + jsonw_string_field(json_wtr, "name", btf_kind_str[i]); + else + jsonw_null_field(json_wtr, "name"); + jsonw_uint_field(json_wtr, "info_sz", l[i].info_sz); + jsonw_uint_field(json_wtr, "elem_sz", l[i].elem_sz); + jsonw_uint_field(json_wtr, "flags", l[i].flags); + jsonw_end_object(json_wtr); + } + jsonw_end_array(json_wtr); + } + jsonw_end_object(json_wtr); /* end metadata object */ + } else { + printf("layout_len %-10u\nlayout_off %-10u\n", + hdr->layout_len, hdr->layout_off); + for (i = 0; i < nr_kinds; i++) { + printf("kind %-4u %-10s info_sz %-4d elem_sz %-4d flags %-4d\n", + i, i < NR_BTF_KINDS ? btf_kind_str[i] : "?", + l[i].info_sz, l[i].elem_sz, l[i].flags); + } + } + + return 0; +} + static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux"; static struct btf *get_vmlinux_btf_from_sysfs(void) @@ -880,7 +964,7 @@ static bool btf_is_kernel_module(__u32 btf_id) static int do_dump(int argc, char **argv) { - bool dump_c = false, sort_dump_c = true; + bool dump_c = false, sort_dump_c = true, dump_meta = false; struct btf *btf = NULL, *base = NULL; __u32 root_type_ids[MAX_ROOT_IDS]; bool have_id_filtering; @@ -990,10 +1074,12 @@ static int do_dump(int argc, char **argv) } if (strcmp(*argv, "c") == 0) { dump_c = true; + } else if (is_prefix(*argv, "meta")) { + dump_meta = true; } else if (strcmp(*argv, "raw") == 0) { dump_c = false; } else { - p_err("unrecognized format specifier: '%s', possible values: raw, c", + p_err("unrecognized format specifier: '%s', possible values: raw, c, meta", *argv); err = -EINVAL; goto done; @@ -1072,6 +1158,8 @@ static int do_dump(int argc, char **argv) goto done; } err = dump_btf_c(btf, root_type_ids, root_type_cnt, sort_dump_c); + } else if (dump_meta) { + err = dump_btf_meta(btf); } else { err = dump_btf_raw(btf, root_type_ids, root_type_cnt); } @@ -1446,7 +1534,7 @@ static int do_help(int argc, char **argv) " %1$s %2$s help\n" "\n" " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n" - " FORMAT := { raw | c [unsorted] }\n" + " FORMAT := { raw | c [unsorted] | meta }\n" " " HELP_SPEC_MAP "\n" " " HELP_SPEC_PROGRAM "\n" " " HELP_SPEC_OPTIONS " |\n" -- 2.39.3