1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2019 Facebook */
13 #include <bpf/libbpf.h>
14 #include <linux/btf.h>
15 #include <linux/hashtable.h>
16 #include <sys/types.h>
19 #include "json_writer.h"
22 static const char * const btf_kind_str[NR_BTF_KINDS] = {
23 [BTF_KIND_UNKN] = "UNKNOWN",
24 [BTF_KIND_INT] = "INT",
25 [BTF_KIND_PTR] = "PTR",
26 [BTF_KIND_ARRAY] = "ARRAY",
27 [BTF_KIND_STRUCT] = "STRUCT",
28 [BTF_KIND_UNION] = "UNION",
29 [BTF_KIND_ENUM] = "ENUM",
30 [BTF_KIND_FWD] = "FWD",
31 [BTF_KIND_TYPEDEF] = "TYPEDEF",
32 [BTF_KIND_VOLATILE] = "VOLATILE",
33 [BTF_KIND_CONST] = "CONST",
34 [BTF_KIND_RESTRICT] = "RESTRICT",
35 [BTF_KIND_FUNC] = "FUNC",
36 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
37 [BTF_KIND_VAR] = "VAR",
38 [BTF_KIND_DATASEC] = "DATASEC",
41 struct btf_attach_table {
42 DECLARE_HASHTABLE(table, 16);
45 struct btf_attach_point {
48 struct hlist_node hash;
51 static const char *btf_int_enc_str(__u8 encoding)
67 static const char *btf_var_linkage_str(__u32 linkage)
72 case BTF_VAR_GLOBAL_ALLOCATED:
73 return "global-alloc";
79 static const char *btf_func_linkage_str(const struct btf_type *t)
81 switch (btf_vlen(t)) {
93 static const char *btf_str(const struct btf *btf, __u32 off)
97 return btf__name_by_offset(btf, off) ? : "(invalid)";
100 static int dump_btf_type(const struct btf *btf, __u32 id,
101 const struct btf_type *t)
103 json_writer_t *w = json_wtr;
106 kind = BTF_INFO_KIND(t->info);
107 safe_kind = kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
110 jsonw_start_object(w);
111 jsonw_uint_field(w, "id", id);
112 jsonw_string_field(w, "kind", btf_kind_str[safe_kind]);
113 jsonw_string_field(w, "name", btf_str(btf, t->name_off));
115 printf("[%u] %s '%s'", id, btf_kind_str[safe_kind],
116 btf_str(btf, t->name_off));
119 switch (BTF_INFO_KIND(t->info)) {
121 __u32 v = *(__u32 *)(t + 1);
124 enc = btf_int_enc_str(BTF_INT_ENCODING(v));
127 jsonw_uint_field(w, "size", t->size);
128 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
129 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
130 jsonw_string_field(w, "encoding", enc);
132 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
133 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
140 case BTF_KIND_VOLATILE:
141 case BTF_KIND_RESTRICT:
142 case BTF_KIND_TYPEDEF:
144 jsonw_uint_field(w, "type_id", t->type);
146 printf(" type_id=%u", t->type);
148 case BTF_KIND_ARRAY: {
149 const struct btf_array *arr = (const void *)(t + 1);
152 jsonw_uint_field(w, "type_id", arr->type);
153 jsonw_uint_field(w, "index_type_id", arr->index_type);
154 jsonw_uint_field(w, "nr_elems", arr->nelems);
156 printf(" type_id=%u index_type_id=%u nr_elems=%u",
157 arr->type, arr->index_type, arr->nelems);
161 case BTF_KIND_STRUCT:
162 case BTF_KIND_UNION: {
163 const struct btf_member *m = (const void *)(t + 1);
164 __u16 vlen = BTF_INFO_VLEN(t->info);
168 jsonw_uint_field(w, "size", t->size);
169 jsonw_uint_field(w, "vlen", vlen);
170 jsonw_name(w, "members");
171 jsonw_start_array(w);
173 printf(" size=%u vlen=%u", t->size, vlen);
175 for (i = 0; i < vlen; i++, m++) {
176 const char *name = btf_str(btf, m->name_off);
177 __u32 bit_off, bit_sz;
179 if (BTF_INFO_KFLAG(t->info)) {
180 bit_off = BTF_MEMBER_BIT_OFFSET(m->offset);
181 bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset);
188 jsonw_start_object(w);
189 jsonw_string_field(w, "name", name);
190 jsonw_uint_field(w, "type_id", m->type);
191 jsonw_uint_field(w, "bits_offset", bit_off);
193 jsonw_uint_field(w, "bitfield_size",
198 printf("\n\t'%s' type_id=%u bits_offset=%u",
199 name, m->type, bit_off);
201 printf(" bitfield_size=%u", bit_sz);
208 case BTF_KIND_ENUM: {
209 const struct btf_enum *v = (const void *)(t + 1);
210 __u16 vlen = BTF_INFO_VLEN(t->info);
214 jsonw_uint_field(w, "size", t->size);
215 jsonw_uint_field(w, "vlen", vlen);
216 jsonw_name(w, "values");
217 jsonw_start_array(w);
219 printf(" size=%u vlen=%u", t->size, vlen);
221 for (i = 0; i < vlen; i++, v++) {
222 const char *name = btf_str(btf, v->name_off);
225 jsonw_start_object(w);
226 jsonw_string_field(w, "name", name);
227 jsonw_uint_field(w, "val", v->val);
230 printf("\n\t'%s' val=%u", name, v->val);
238 const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union"
242 jsonw_string_field(w, "fwd_kind", fwd_kind);
244 printf(" fwd_kind=%s", fwd_kind);
247 case BTF_KIND_FUNC: {
248 const char *linkage = btf_func_linkage_str(t);
251 jsonw_uint_field(w, "type_id", t->type);
252 jsonw_string_field(w, "linkage", linkage);
254 printf(" type_id=%u linkage=%s", t->type, linkage);
258 case BTF_KIND_FUNC_PROTO: {
259 const struct btf_param *p = (const void *)(t + 1);
260 __u16 vlen = BTF_INFO_VLEN(t->info);
264 jsonw_uint_field(w, "ret_type_id", t->type);
265 jsonw_uint_field(w, "vlen", vlen);
266 jsonw_name(w, "params");
267 jsonw_start_array(w);
269 printf(" ret_type_id=%u vlen=%u", t->type, vlen);
271 for (i = 0; i < vlen; i++, p++) {
272 const char *name = btf_str(btf, p->name_off);
275 jsonw_start_object(w);
276 jsonw_string_field(w, "name", name);
277 jsonw_uint_field(w, "type_id", p->type);
280 printf("\n\t'%s' type_id=%u", name, p->type);
288 const struct btf_var *v = (const void *)(t + 1);
291 linkage = btf_var_linkage_str(v->linkage);
294 jsonw_uint_field(w, "type_id", t->type);
295 jsonw_string_field(w, "linkage", linkage);
297 printf(" type_id=%u, linkage=%s", t->type, linkage);
301 case BTF_KIND_DATASEC: {
302 const struct btf_var_secinfo *v = (const void *)(t+1);
303 __u16 vlen = BTF_INFO_VLEN(t->info);
307 jsonw_uint_field(w, "size", t->size);
308 jsonw_uint_field(w, "vlen", vlen);
309 jsonw_name(w, "vars");
310 jsonw_start_array(w);
312 printf(" size=%u vlen=%u", t->size, vlen);
314 for (i = 0; i < vlen; i++, v++) {
316 jsonw_start_object(w);
317 jsonw_uint_field(w, "type_id", v->type);
318 jsonw_uint_field(w, "offset", v->offset);
319 jsonw_uint_field(w, "size", v->size);
322 printf("\n\ttype_id=%u offset=%u size=%u",
323 v->type, v->offset, v->size);
335 jsonw_end_object(json_wtr);
342 static int dump_btf_raw(const struct btf *btf,
343 __u32 *root_type_ids, int root_type_cnt)
345 const struct btf_type *t;
349 jsonw_start_object(json_wtr);
350 jsonw_name(json_wtr, "types");
351 jsonw_start_array(json_wtr);
355 for (i = 0; i < root_type_cnt; i++) {
356 t = btf__type_by_id(btf, root_type_ids[i]);
357 dump_btf_type(btf, root_type_ids[i], t);
360 const struct btf *base;
361 int cnt = btf__get_nr_types(btf);
364 base = btf__base_btf(btf);
366 start_id = btf__get_nr_types(base) + 1;
368 for (i = start_id; i <= cnt; i++) {
369 t = btf__type_by_id(btf, i);
370 dump_btf_type(btf, i, t);
375 jsonw_end_array(json_wtr);
376 jsonw_end_object(json_wtr);
381 static void __printf(2, 0) btf_dump_printf(void *ctx,
382 const char *fmt, va_list args)
384 vfprintf(stdout, fmt, args);
387 static int dump_btf_c(const struct btf *btf,
388 __u32 *root_type_ids, int root_type_cnt)
393 d = btf_dump__new(btf, NULL, NULL, btf_dump_printf);
397 printf("#ifndef __VMLINUX_H__\n");
398 printf("#define __VMLINUX_H__\n");
400 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
401 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
402 printf("#endif\n\n");
405 for (i = 0; i < root_type_cnt; i++) {
406 err = btf_dump__dump_type(d, root_type_ids[i]);
411 int cnt = btf__get_nr_types(btf);
413 for (i = 1; i <= cnt; i++) {
414 err = btf_dump__dump_type(d, i);
420 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
421 printf("#pragma clang attribute pop\n");
424 printf("#endif /* __VMLINUX_H__ */\n");
431 static int do_dump(int argc, char **argv)
433 struct btf *btf = NULL, *base = NULL;
434 __u32 root_type_ids[2];
435 int root_type_cnt = 0;
447 if (is_prefix(src, "map")) {
448 struct bpf_map_info info = {};
449 __u32 len = sizeof(info);
456 fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
460 btf_id = info.btf_id;
461 if (argc && is_prefix(*argv, "key")) {
462 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
464 } else if (argc && is_prefix(*argv, "value")) {
465 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
467 } else if (argc && is_prefix(*argv, "all")) {
469 } else if (argc && is_prefix(*argv, "kv")) {
470 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
471 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
474 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
475 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
477 } else if (is_prefix(src, "prog")) {
478 struct bpf_prog_info info = {};
479 __u32 len = sizeof(info);
486 fd = prog_parse_fd(&argc, &argv);
490 err = bpf_obj_get_info_by_fd(fd, &info, &len);
492 p_err("can't get prog info: %s", strerror(errno));
496 btf_id = info.btf_id;
497 } else if (is_prefix(src, "id")) {
500 btf_id = strtoul(*argv, &endptr, 0);
502 p_err("can't parse %s as ID", *argv);
506 } else if (is_prefix(src, "file")) {
507 const char sysfs_prefix[] = "/sys/kernel/btf/";
508 const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
511 strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
512 strcmp(*argv, sysfs_vmlinux) != 0) {
513 base = btf__parse(sysfs_vmlinux, NULL);
514 if (libbpf_get_error(base)) {
515 p_err("failed to parse vmlinux BTF at '%s': %ld\n",
516 sysfs_vmlinux, libbpf_get_error(base));
521 btf = btf__parse_split(*argv, base ?: base_btf);
525 p_err("failed to load BTF from %s: %s",
526 *argv, strerror(err));
532 p_err("unrecognized BTF source specifier: '%s'", src);
537 if (is_prefix(*argv, "format")) {
540 p_err("expecting value for 'format' option\n");
543 if (strcmp(*argv, "c") == 0) {
545 } else if (strcmp(*argv, "raw") == 0) {
548 p_err("unrecognized format specifier: '%s', possible values: raw, c",
554 p_err("unrecognized option: '%s'", *argv);
560 err = btf__get_from_id(btf_id, &btf);
562 p_err("get btf by id (%u): %s", btf_id, strerror(err));
567 p_err("can't find btf with ID (%u)", btf_id);
574 p_err("JSON output for C-syntax dump is not supported");
578 err = dump_btf_c(btf, root_type_ids, root_type_cnt);
580 err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
590 static int btf_parse_fd(int *argc, char ***argv)
596 if (!is_prefix(*argv[0], "id")) {
597 p_err("expected 'id', got: '%s'?", **argv);
602 id = strtoul(**argv, &endptr, 0);
604 p_err("can't parse %s as ID", **argv);
609 fd = bpf_btf_get_fd_by_id(id);
611 p_err("can't get BTF object by id (%u): %s",
612 id, strerror(errno));
617 static void delete_btf_table(struct btf_attach_table *tab)
619 struct btf_attach_point *obj;
620 struct hlist_node *tmp;
624 hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
625 hash_del(&obj->hash);
631 build_btf_type_table(struct btf_attach_table *tab, enum bpf_obj_type type,
632 void *info, __u32 *len)
634 static const char * const names[] = {
635 [BPF_OBJ_UNKNOWN] = "unknown",
636 [BPF_OBJ_PROG] = "prog",
637 [BPF_OBJ_MAP] = "map",
639 struct btf_attach_point *obj_node;
640 __u32 btf_id, id = 0;
647 err = bpf_prog_get_next_id(id, &id);
650 err = bpf_map_get_next_id(id, &id);
654 p_err("unexpected object type: %d", type);
658 if (errno == ENOENT) {
662 p_err("can't get next %s: %s%s", names[type],
664 errno == EINVAL ? " -- kernel too old?" : "");
670 fd = bpf_prog_get_fd_by_id(id);
673 fd = bpf_map_get_fd_by_id(id);
677 p_err("unexpected object type: %d", type);
683 p_err("can't get %s by id (%u): %s", names[type], id,
689 memset(info, 0, *len);
690 err = bpf_obj_get_info_by_fd(fd, info, len);
693 p_err("can't get %s info: %s", names[type],
700 btf_id = ((struct bpf_prog_info *)info)->btf_id;
703 btf_id = ((struct bpf_map_info *)info)->btf_id;
707 p_err("unexpected object type: %d", type);
713 obj_node = calloc(1, sizeof(*obj_node));
715 p_err("failed to allocate memory: %s", strerror(errno));
720 obj_node->obj_id = id;
721 obj_node->btf_id = btf_id;
722 hash_add(tab->table, &obj_node->hash, obj_node->btf_id);
728 delete_btf_table(tab);
733 build_btf_tables(struct btf_attach_table *btf_prog_table,
734 struct btf_attach_table *btf_map_table)
736 struct bpf_prog_info prog_info;
737 __u32 prog_len = sizeof(prog_info);
738 struct bpf_map_info map_info;
739 __u32 map_len = sizeof(map_info);
742 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
747 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
750 delete_btf_table(btf_prog_table);
758 show_btf_plain(struct bpf_btf_info *info, int fd,
759 struct btf_attach_table *btf_prog_table,
760 struct btf_attach_table *btf_map_table)
762 struct btf_attach_point *obj;
763 const char *name = u64_to_ptr(info->name);
766 printf("%u: ", info->id);
767 if (info->kernel_btf)
768 printf("name [%s] ", name);
769 else if (name && name[0])
770 printf("name %s ", name);
772 printf("name <anon> ");
773 printf("size %uB", info->btf_size);
776 hash_for_each_possible(btf_prog_table->table, obj, hash, info->id) {
777 if (obj->btf_id == info->id)
778 printf("%s%u", n++ == 0 ? " prog_ids " : ",",
783 hash_for_each_possible(btf_map_table->table, obj, hash, info->id) {
784 if (obj->btf_id == info->id)
785 printf("%s%u", n++ == 0 ? " map_ids " : ",",
788 emit_obj_refs_plain(&refs_table, info->id, "\n\tpids ");
794 show_btf_json(struct bpf_btf_info *info, int fd,
795 struct btf_attach_table *btf_prog_table,
796 struct btf_attach_table *btf_map_table)
798 struct btf_attach_point *obj;
799 const char *name = u64_to_ptr(info->name);
801 jsonw_start_object(json_wtr); /* btf object */
802 jsonw_uint_field(json_wtr, "id", info->id);
803 jsonw_uint_field(json_wtr, "size", info->btf_size);
805 jsonw_name(json_wtr, "prog_ids");
806 jsonw_start_array(json_wtr); /* prog_ids */
807 hash_for_each_possible(btf_prog_table->table, obj, hash,
809 if (obj->btf_id == info->id)
810 jsonw_uint(json_wtr, obj->obj_id);
812 jsonw_end_array(json_wtr); /* prog_ids */
814 jsonw_name(json_wtr, "map_ids");
815 jsonw_start_array(json_wtr); /* map_ids */
816 hash_for_each_possible(btf_map_table->table, obj, hash,
818 if (obj->btf_id == info->id)
819 jsonw_uint(json_wtr, obj->obj_id);
821 jsonw_end_array(json_wtr); /* map_ids */
823 emit_obj_refs_json(&refs_table, info->id, json_wtr); /* pids */
825 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
828 jsonw_string_field(json_wtr, "name", name);
830 jsonw_end_object(json_wtr); /* btf object */
834 show_btf(int fd, struct btf_attach_table *btf_prog_table,
835 struct btf_attach_table *btf_map_table)
837 struct bpf_btf_info info;
838 __u32 len = sizeof(info);
842 memset(&info, 0, sizeof(info));
843 err = bpf_obj_get_info_by_fd(fd, &info, &len);
845 p_err("can't get BTF object info: %s", strerror(errno));
848 /* if kernel support emitting BTF object name, pass name pointer */
850 memset(&info, 0, sizeof(info));
851 info.name_len = sizeof(name);
852 info.name = ptr_to_u64(name);
855 err = bpf_obj_get_info_by_fd(fd, &info, &len);
857 p_err("can't get BTF object info: %s", strerror(errno));
863 show_btf_json(&info, fd, btf_prog_table, btf_map_table);
865 show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
870 static int do_show(int argc, char **argv)
872 struct btf_attach_table btf_prog_table;
873 struct btf_attach_table btf_map_table;
878 fd = btf_parse_fd(&argc, &argv);
889 hash_init(btf_prog_table.table);
890 hash_init(btf_map_table.table);
891 err = build_btf_tables(&btf_prog_table, &btf_map_table);
897 build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
900 err = show_btf(fd, &btf_prog_table, &btf_map_table);
906 jsonw_start_array(json_wtr); /* root array */
909 err = bpf_btf_get_next_id(id, &id);
911 if (errno == ENOENT) {
915 p_err("can't get next BTF object: %s%s",
917 errno == EINVAL ? " -- kernel too old?" : "");
922 fd = bpf_btf_get_fd_by_id(id);
926 p_err("can't get BTF object by id (%u): %s",
927 id, strerror(errno));
932 err = show_btf(fd, &btf_prog_table, &btf_map_table);
939 jsonw_end_array(json_wtr); /* root array */
942 delete_btf_table(&btf_prog_table);
943 delete_btf_table(&btf_map_table);
944 delete_obj_refs_table(&refs_table);
949 static int do_help(int argc, char **argv)
952 jsonw_null(json_wtr);
957 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
958 " %1$s %2$s dump BTF_SRC [format FORMAT]\n"
961 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
962 " FORMAT := { raw | c }\n"
963 " " HELP_SPEC_MAP "\n"
964 " " HELP_SPEC_PROGRAM "\n"
965 " " HELP_SPEC_OPTIONS "\n"
972 static const struct cmd cmds[] = {
980 int do_btf(int argc, char **argv)
982 return cmd_select(cmds, argc, argv, do_help);