0001
0002
0003
0004 #include <errno.h>
0005 #include <fcntl.h>
0006 #include <linux/err.h>
0007 #include <stdbool.h>
0008 #include <stdio.h>
0009 #include <string.h>
0010 #include <unistd.h>
0011 #include <linux/btf.h>
0012 #include <sys/types.h>
0013 #include <sys/stat.h>
0014
0015 #include <bpf/bpf.h>
0016 #include <bpf/btf.h>
0017 #include <bpf/hashmap.h>
0018 #include <bpf/libbpf.h>
0019
0020 #include "json_writer.h"
0021 #include "main.h"
0022
0023 static const char * const btf_kind_str[NR_BTF_KINDS] = {
0024 [BTF_KIND_UNKN] = "UNKNOWN",
0025 [BTF_KIND_INT] = "INT",
0026 [BTF_KIND_PTR] = "PTR",
0027 [BTF_KIND_ARRAY] = "ARRAY",
0028 [BTF_KIND_STRUCT] = "STRUCT",
0029 [BTF_KIND_UNION] = "UNION",
0030 [BTF_KIND_ENUM] = "ENUM",
0031 [BTF_KIND_FWD] = "FWD",
0032 [BTF_KIND_TYPEDEF] = "TYPEDEF",
0033 [BTF_KIND_VOLATILE] = "VOLATILE",
0034 [BTF_KIND_CONST] = "CONST",
0035 [BTF_KIND_RESTRICT] = "RESTRICT",
0036 [BTF_KIND_FUNC] = "FUNC",
0037 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
0038 [BTF_KIND_VAR] = "VAR",
0039 [BTF_KIND_DATASEC] = "DATASEC",
0040 [BTF_KIND_FLOAT] = "FLOAT",
0041 [BTF_KIND_DECL_TAG] = "DECL_TAG",
0042 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
0043 [BTF_KIND_ENUM64] = "ENUM64",
0044 };
0045
0046 struct btf_attach_point {
0047 __u32 obj_id;
0048 __u32 btf_id;
0049 };
0050
0051 static const char *btf_int_enc_str(__u8 encoding)
0052 {
0053 switch (encoding) {
0054 case 0:
0055 return "(none)";
0056 case BTF_INT_SIGNED:
0057 return "SIGNED";
0058 case BTF_INT_CHAR:
0059 return "CHAR";
0060 case BTF_INT_BOOL:
0061 return "BOOL";
0062 default:
0063 return "UNKN";
0064 }
0065 }
0066
0067 static const char *btf_var_linkage_str(__u32 linkage)
0068 {
0069 switch (linkage) {
0070 case BTF_VAR_STATIC:
0071 return "static";
0072 case BTF_VAR_GLOBAL_ALLOCATED:
0073 return "global";
0074 case BTF_VAR_GLOBAL_EXTERN:
0075 return "extern";
0076 default:
0077 return "(unknown)";
0078 }
0079 }
0080
0081 static const char *btf_func_linkage_str(const struct btf_type *t)
0082 {
0083 switch (btf_vlen(t)) {
0084 case BTF_FUNC_STATIC:
0085 return "static";
0086 case BTF_FUNC_GLOBAL:
0087 return "global";
0088 case BTF_FUNC_EXTERN:
0089 return "extern";
0090 default:
0091 return "(unknown)";
0092 }
0093 }
0094
0095 static const char *btf_str(const struct btf *btf, __u32 off)
0096 {
0097 if (!off)
0098 return "(anon)";
0099 return btf__name_by_offset(btf, off) ? : "(invalid)";
0100 }
0101
0102 static int btf_kind_safe(int kind)
0103 {
0104 return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
0105 }
0106
0107 static int dump_btf_type(const struct btf *btf, __u32 id,
0108 const struct btf_type *t)
0109 {
0110 json_writer_t *w = json_wtr;
0111 int kind = btf_kind(t);
0112
0113 if (json_output) {
0114 jsonw_start_object(w);
0115 jsonw_uint_field(w, "id", id);
0116 jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
0117 jsonw_string_field(w, "name", btf_str(btf, t->name_off));
0118 } else {
0119 printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
0120 btf_str(btf, t->name_off));
0121 }
0122
0123 switch (kind) {
0124 case BTF_KIND_INT: {
0125 __u32 v = *(__u32 *)(t + 1);
0126 const char *enc;
0127
0128 enc = btf_int_enc_str(BTF_INT_ENCODING(v));
0129
0130 if (json_output) {
0131 jsonw_uint_field(w, "size", t->size);
0132 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
0133 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
0134 jsonw_string_field(w, "encoding", enc);
0135 } else {
0136 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
0137 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
0138 enc);
0139 }
0140 break;
0141 }
0142 case BTF_KIND_PTR:
0143 case BTF_KIND_CONST:
0144 case BTF_KIND_VOLATILE:
0145 case BTF_KIND_RESTRICT:
0146 case BTF_KIND_TYPEDEF:
0147 case BTF_KIND_TYPE_TAG:
0148 if (json_output)
0149 jsonw_uint_field(w, "type_id", t->type);
0150 else
0151 printf(" type_id=%u", t->type);
0152 break;
0153 case BTF_KIND_ARRAY: {
0154 const struct btf_array *arr = (const void *)(t + 1);
0155
0156 if (json_output) {
0157 jsonw_uint_field(w, "type_id", arr->type);
0158 jsonw_uint_field(w, "index_type_id", arr->index_type);
0159 jsonw_uint_field(w, "nr_elems", arr->nelems);
0160 } else {
0161 printf(" type_id=%u index_type_id=%u nr_elems=%u",
0162 arr->type, arr->index_type, arr->nelems);
0163 }
0164 break;
0165 }
0166 case BTF_KIND_STRUCT:
0167 case BTF_KIND_UNION: {
0168 const struct btf_member *m = (const void *)(t + 1);
0169 __u16 vlen = BTF_INFO_VLEN(t->info);
0170 int i;
0171
0172 if (json_output) {
0173 jsonw_uint_field(w, "size", t->size);
0174 jsonw_uint_field(w, "vlen", vlen);
0175 jsonw_name(w, "members");
0176 jsonw_start_array(w);
0177 } else {
0178 printf(" size=%u vlen=%u", t->size, vlen);
0179 }
0180 for (i = 0; i < vlen; i++, m++) {
0181 const char *name = btf_str(btf, m->name_off);
0182 __u32 bit_off, bit_sz;
0183
0184 if (BTF_INFO_KFLAG(t->info)) {
0185 bit_off = BTF_MEMBER_BIT_OFFSET(m->offset);
0186 bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset);
0187 } else {
0188 bit_off = m->offset;
0189 bit_sz = 0;
0190 }
0191
0192 if (json_output) {
0193 jsonw_start_object(w);
0194 jsonw_string_field(w, "name", name);
0195 jsonw_uint_field(w, "type_id", m->type);
0196 jsonw_uint_field(w, "bits_offset", bit_off);
0197 if (bit_sz) {
0198 jsonw_uint_field(w, "bitfield_size",
0199 bit_sz);
0200 }
0201 jsonw_end_object(w);
0202 } else {
0203 printf("\n\t'%s' type_id=%u bits_offset=%u",
0204 name, m->type, bit_off);
0205 if (bit_sz)
0206 printf(" bitfield_size=%u", bit_sz);
0207 }
0208 }
0209 if (json_output)
0210 jsonw_end_array(w);
0211 break;
0212 }
0213 case BTF_KIND_ENUM: {
0214 const struct btf_enum *v = (const void *)(t + 1);
0215 __u16 vlen = BTF_INFO_VLEN(t->info);
0216 const char *encoding;
0217 int i;
0218
0219 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
0220 if (json_output) {
0221 jsonw_string_field(w, "encoding", encoding);
0222 jsonw_uint_field(w, "size", t->size);
0223 jsonw_uint_field(w, "vlen", vlen);
0224 jsonw_name(w, "values");
0225 jsonw_start_array(w);
0226 } else {
0227 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
0228 }
0229 for (i = 0; i < vlen; i++, v++) {
0230 const char *name = btf_str(btf, v->name_off);
0231
0232 if (json_output) {
0233 jsonw_start_object(w);
0234 jsonw_string_field(w, "name", name);
0235 if (btf_kflag(t))
0236 jsonw_int_field(w, "val", v->val);
0237 else
0238 jsonw_uint_field(w, "val", v->val);
0239 jsonw_end_object(w);
0240 } else {
0241 if (btf_kflag(t))
0242 printf("\n\t'%s' val=%d", name, v->val);
0243 else
0244 printf("\n\t'%s' val=%u", name, v->val);
0245 }
0246 }
0247 if (json_output)
0248 jsonw_end_array(w);
0249 break;
0250 }
0251 case BTF_KIND_ENUM64: {
0252 const struct btf_enum64 *v = btf_enum64(t);
0253 __u16 vlen = btf_vlen(t);
0254 const char *encoding;
0255 int i;
0256
0257 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
0258 if (json_output) {
0259 jsonw_string_field(w, "encoding", encoding);
0260 jsonw_uint_field(w, "size", t->size);
0261 jsonw_uint_field(w, "vlen", vlen);
0262 jsonw_name(w, "values");
0263 jsonw_start_array(w);
0264 } else {
0265 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
0266 }
0267 for (i = 0; i < vlen; i++, v++) {
0268 const char *name = btf_str(btf, v->name_off);
0269 __u64 val = ((__u64)v->val_hi32 << 32) | v->val_lo32;
0270
0271 if (json_output) {
0272 jsonw_start_object(w);
0273 jsonw_string_field(w, "name", name);
0274 if (btf_kflag(t))
0275 jsonw_int_field(w, "val", val);
0276 else
0277 jsonw_uint_field(w, "val", val);
0278 jsonw_end_object(w);
0279 } else {
0280 if (btf_kflag(t))
0281 printf("\n\t'%s' val=%lldLL", name,
0282 (unsigned long long)val);
0283 else
0284 printf("\n\t'%s' val=%lluULL", name,
0285 (unsigned long long)val);
0286 }
0287 }
0288 if (json_output)
0289 jsonw_end_array(w);
0290 break;
0291 }
0292 case BTF_KIND_FWD: {
0293 const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union"
0294 : "struct";
0295
0296 if (json_output)
0297 jsonw_string_field(w, "fwd_kind", fwd_kind);
0298 else
0299 printf(" fwd_kind=%s", fwd_kind);
0300 break;
0301 }
0302 case BTF_KIND_FUNC: {
0303 const char *linkage = btf_func_linkage_str(t);
0304
0305 if (json_output) {
0306 jsonw_uint_field(w, "type_id", t->type);
0307 jsonw_string_field(w, "linkage", linkage);
0308 } else {
0309 printf(" type_id=%u linkage=%s", t->type, linkage);
0310 }
0311 break;
0312 }
0313 case BTF_KIND_FUNC_PROTO: {
0314 const struct btf_param *p = (const void *)(t + 1);
0315 __u16 vlen = BTF_INFO_VLEN(t->info);
0316 int i;
0317
0318 if (json_output) {
0319 jsonw_uint_field(w, "ret_type_id", t->type);
0320 jsonw_uint_field(w, "vlen", vlen);
0321 jsonw_name(w, "params");
0322 jsonw_start_array(w);
0323 } else {
0324 printf(" ret_type_id=%u vlen=%u", t->type, vlen);
0325 }
0326 for (i = 0; i < vlen; i++, p++) {
0327 const char *name = btf_str(btf, p->name_off);
0328
0329 if (json_output) {
0330 jsonw_start_object(w);
0331 jsonw_string_field(w, "name", name);
0332 jsonw_uint_field(w, "type_id", p->type);
0333 jsonw_end_object(w);
0334 } else {
0335 printf("\n\t'%s' type_id=%u", name, p->type);
0336 }
0337 }
0338 if (json_output)
0339 jsonw_end_array(w);
0340 break;
0341 }
0342 case BTF_KIND_VAR: {
0343 const struct btf_var *v = (const void *)(t + 1);
0344 const char *linkage;
0345
0346 linkage = btf_var_linkage_str(v->linkage);
0347
0348 if (json_output) {
0349 jsonw_uint_field(w, "type_id", t->type);
0350 jsonw_string_field(w, "linkage", linkage);
0351 } else {
0352 printf(" type_id=%u, linkage=%s", t->type, linkage);
0353 }
0354 break;
0355 }
0356 case BTF_KIND_DATASEC: {
0357 const struct btf_var_secinfo *v = (const void *)(t + 1);
0358 const struct btf_type *vt;
0359 __u16 vlen = BTF_INFO_VLEN(t->info);
0360 int i;
0361
0362 if (json_output) {
0363 jsonw_uint_field(w, "size", t->size);
0364 jsonw_uint_field(w, "vlen", vlen);
0365 jsonw_name(w, "vars");
0366 jsonw_start_array(w);
0367 } else {
0368 printf(" size=%u vlen=%u", t->size, vlen);
0369 }
0370 for (i = 0; i < vlen; i++, v++) {
0371 if (json_output) {
0372 jsonw_start_object(w);
0373 jsonw_uint_field(w, "type_id", v->type);
0374 jsonw_uint_field(w, "offset", v->offset);
0375 jsonw_uint_field(w, "size", v->size);
0376 jsonw_end_object(w);
0377 } else {
0378 printf("\n\ttype_id=%u offset=%u size=%u",
0379 v->type, v->offset, v->size);
0380
0381 if (v->type < btf__type_cnt(btf)) {
0382 vt = btf__type_by_id(btf, v->type);
0383 printf(" (%s '%s')",
0384 btf_kind_str[btf_kind_safe(btf_kind(vt))],
0385 btf_str(btf, vt->name_off));
0386 }
0387 }
0388 }
0389 if (json_output)
0390 jsonw_end_array(w);
0391 break;
0392 }
0393 case BTF_KIND_FLOAT: {
0394 if (json_output)
0395 jsonw_uint_field(w, "size", t->size);
0396 else
0397 printf(" size=%u", t->size);
0398 break;
0399 }
0400 case BTF_KIND_DECL_TAG: {
0401 const struct btf_decl_tag *tag = (const void *)(t + 1);
0402
0403 if (json_output) {
0404 jsonw_uint_field(w, "type_id", t->type);
0405 jsonw_int_field(w, "component_idx", tag->component_idx);
0406 } else {
0407 printf(" type_id=%u component_idx=%d", t->type, tag->component_idx);
0408 }
0409 break;
0410 }
0411 default:
0412 break;
0413 }
0414
0415 if (json_output)
0416 jsonw_end_object(json_wtr);
0417 else
0418 printf("\n");
0419
0420 return 0;
0421 }
0422
0423 static int dump_btf_raw(const struct btf *btf,
0424 __u32 *root_type_ids, int root_type_cnt)
0425 {
0426 const struct btf_type *t;
0427 int i;
0428
0429 if (json_output) {
0430 jsonw_start_object(json_wtr);
0431 jsonw_name(json_wtr, "types");
0432 jsonw_start_array(json_wtr);
0433 }
0434
0435 if (root_type_cnt) {
0436 for (i = 0; i < root_type_cnt; i++) {
0437 t = btf__type_by_id(btf, root_type_ids[i]);
0438 dump_btf_type(btf, root_type_ids[i], t);
0439 }
0440 } else {
0441 const struct btf *base;
0442 int cnt = btf__type_cnt(btf);
0443 int start_id = 1;
0444
0445 base = btf__base_btf(btf);
0446 if (base)
0447 start_id = btf__type_cnt(base);
0448
0449 for (i = start_id; i < cnt; i++) {
0450 t = btf__type_by_id(btf, i);
0451 dump_btf_type(btf, i, t);
0452 }
0453 }
0454
0455 if (json_output) {
0456 jsonw_end_array(json_wtr);
0457 jsonw_end_object(json_wtr);
0458 }
0459 return 0;
0460 }
0461
0462 static void __printf(2, 0) btf_dump_printf(void *ctx,
0463 const char *fmt, va_list args)
0464 {
0465 vfprintf(stdout, fmt, args);
0466 }
0467
0468 static int dump_btf_c(const struct btf *btf,
0469 __u32 *root_type_ids, int root_type_cnt)
0470 {
0471 struct btf_dump *d;
0472 int err = 0, i;
0473
0474 d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);
0475 err = libbpf_get_error(d);
0476 if (err)
0477 return err;
0478
0479 printf("#ifndef __VMLINUX_H__\n");
0480 printf("#define __VMLINUX_H__\n");
0481 printf("\n");
0482 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
0483 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
0484 printf("#endif\n\n");
0485
0486 if (root_type_cnt) {
0487 for (i = 0; i < root_type_cnt; i++) {
0488 err = btf_dump__dump_type(d, root_type_ids[i]);
0489 if (err)
0490 goto done;
0491 }
0492 } else {
0493 int cnt = btf__type_cnt(btf);
0494
0495 for (i = 1; i < cnt; i++) {
0496 err = btf_dump__dump_type(d, i);
0497 if (err)
0498 goto done;
0499 }
0500 }
0501
0502 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
0503 printf("#pragma clang attribute pop\n");
0504 printf("#endif\n");
0505 printf("\n");
0506 printf("#endif /* __VMLINUX_H__ */\n");
0507
0508 done:
0509 btf_dump__free(d);
0510 return err;
0511 }
0512
0513 static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
0514
0515 static struct btf *get_vmlinux_btf_from_sysfs(void)
0516 {
0517 struct btf *base;
0518
0519 base = btf__parse(sysfs_vmlinux, NULL);
0520 if (libbpf_get_error(base)) {
0521 p_err("failed to parse vmlinux BTF at '%s': %ld\n",
0522 sysfs_vmlinux, libbpf_get_error(base));
0523 base = NULL;
0524 }
0525
0526 return base;
0527 }
0528
0529 #define BTF_NAME_BUFF_LEN 64
0530
0531 static bool btf_is_kernel_module(__u32 btf_id)
0532 {
0533 struct bpf_btf_info btf_info = {};
0534 char btf_name[BTF_NAME_BUFF_LEN];
0535 int btf_fd;
0536 __u32 len;
0537 int err;
0538
0539 btf_fd = bpf_btf_get_fd_by_id(btf_id);
0540 if (btf_fd < 0) {
0541 p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno));
0542 return false;
0543 }
0544
0545 len = sizeof(btf_info);
0546 btf_info.name = ptr_to_u64(btf_name);
0547 btf_info.name_len = sizeof(btf_name);
0548 err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
0549 close(btf_fd);
0550 if (err) {
0551 p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno));
0552 return false;
0553 }
0554
0555 return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0;
0556 }
0557
0558 static int do_dump(int argc, char **argv)
0559 {
0560 struct btf *btf = NULL, *base = NULL;
0561 __u32 root_type_ids[2];
0562 int root_type_cnt = 0;
0563 bool dump_c = false;
0564 __u32 btf_id = -1;
0565 const char *src;
0566 int fd = -1;
0567 int err;
0568
0569 if (!REQ_ARGS(2)) {
0570 usage();
0571 return -1;
0572 }
0573 src = GET_ARG();
0574 if (is_prefix(src, "map")) {
0575 struct bpf_map_info info = {};
0576 __u32 len = sizeof(info);
0577
0578 if (!REQ_ARGS(2)) {
0579 usage();
0580 return -1;
0581 }
0582
0583 fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
0584 if (fd < 0)
0585 return -1;
0586
0587 btf_id = info.btf_id;
0588 if (argc && is_prefix(*argv, "key")) {
0589 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
0590 NEXT_ARG();
0591 } else if (argc && is_prefix(*argv, "value")) {
0592 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
0593 NEXT_ARG();
0594 } else if (argc && is_prefix(*argv, "all")) {
0595 NEXT_ARG();
0596 } else if (argc && is_prefix(*argv, "kv")) {
0597 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
0598 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
0599 NEXT_ARG();
0600 } else {
0601 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
0602 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
0603 }
0604 } else if (is_prefix(src, "prog")) {
0605 struct bpf_prog_info info = {};
0606 __u32 len = sizeof(info);
0607
0608 if (!REQ_ARGS(2)) {
0609 usage();
0610 return -1;
0611 }
0612
0613 fd = prog_parse_fd(&argc, &argv);
0614 if (fd < 0)
0615 return -1;
0616
0617 err = bpf_obj_get_info_by_fd(fd, &info, &len);
0618 if (err) {
0619 p_err("can't get prog info: %s", strerror(errno));
0620 goto done;
0621 }
0622
0623 btf_id = info.btf_id;
0624 } else if (is_prefix(src, "id")) {
0625 char *endptr;
0626
0627 btf_id = strtoul(*argv, &endptr, 0);
0628 if (*endptr) {
0629 p_err("can't parse %s as ID", *argv);
0630 return -1;
0631 }
0632 NEXT_ARG();
0633 } else if (is_prefix(src, "file")) {
0634 const char sysfs_prefix[] = "/sys/kernel/btf/";
0635
0636 if (!base_btf &&
0637 strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
0638 strcmp(*argv, sysfs_vmlinux) != 0)
0639 base = get_vmlinux_btf_from_sysfs();
0640
0641 btf = btf__parse_split(*argv, base ?: base_btf);
0642 err = libbpf_get_error(btf);
0643 if (err) {
0644 btf = NULL;
0645 p_err("failed to load BTF from %s: %s",
0646 *argv, strerror(err));
0647 goto done;
0648 }
0649 NEXT_ARG();
0650 } else {
0651 err = -1;
0652 p_err("unrecognized BTF source specifier: '%s'", src);
0653 goto done;
0654 }
0655
0656 while (argc) {
0657 if (is_prefix(*argv, "format")) {
0658 NEXT_ARG();
0659 if (argc < 1) {
0660 p_err("expecting value for 'format' option\n");
0661 err = -EINVAL;
0662 goto done;
0663 }
0664 if (strcmp(*argv, "c") == 0) {
0665 dump_c = true;
0666 } else if (strcmp(*argv, "raw") == 0) {
0667 dump_c = false;
0668 } else {
0669 p_err("unrecognized format specifier: '%s', possible values: raw, c",
0670 *argv);
0671 err = -EINVAL;
0672 goto done;
0673 }
0674 NEXT_ARG();
0675 } else {
0676 p_err("unrecognized option: '%s'", *argv);
0677 err = -EINVAL;
0678 goto done;
0679 }
0680 }
0681
0682 if (!btf) {
0683 if (!base_btf && btf_is_kernel_module(btf_id)) {
0684 p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)",
0685 sysfs_vmlinux);
0686 base_btf = get_vmlinux_btf_from_sysfs();
0687 }
0688
0689 btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
0690 err = libbpf_get_error(btf);
0691 if (err) {
0692 p_err("get btf by id (%u): %s", btf_id, strerror(err));
0693 goto done;
0694 }
0695 }
0696
0697 if (dump_c) {
0698 if (json_output) {
0699 p_err("JSON output for C-syntax dump is not supported");
0700 err = -ENOTSUP;
0701 goto done;
0702 }
0703 err = dump_btf_c(btf, root_type_ids, root_type_cnt);
0704 } else {
0705 err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
0706 }
0707
0708 done:
0709 close(fd);
0710 btf__free(btf);
0711 btf__free(base);
0712 return err;
0713 }
0714
0715 static int btf_parse_fd(int *argc, char ***argv)
0716 {
0717 unsigned int id;
0718 char *endptr;
0719 int fd;
0720
0721 if (!is_prefix(*argv[0], "id")) {
0722 p_err("expected 'id', got: '%s'?", **argv);
0723 return -1;
0724 }
0725 NEXT_ARGP();
0726
0727 id = strtoul(**argv, &endptr, 0);
0728 if (*endptr) {
0729 p_err("can't parse %s as ID", **argv);
0730 return -1;
0731 }
0732 NEXT_ARGP();
0733
0734 fd = bpf_btf_get_fd_by_id(id);
0735 if (fd < 0)
0736 p_err("can't get BTF object by id (%u): %s",
0737 id, strerror(errno));
0738
0739 return fd;
0740 }
0741
0742 static int
0743 build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type,
0744 void *info, __u32 *len)
0745 {
0746 static const char * const names[] = {
0747 [BPF_OBJ_UNKNOWN] = "unknown",
0748 [BPF_OBJ_PROG] = "prog",
0749 [BPF_OBJ_MAP] = "map",
0750 };
0751 __u32 btf_id, id = 0;
0752 int err;
0753 int fd;
0754
0755 while (true) {
0756 switch (type) {
0757 case BPF_OBJ_PROG:
0758 err = bpf_prog_get_next_id(id, &id);
0759 break;
0760 case BPF_OBJ_MAP:
0761 err = bpf_map_get_next_id(id, &id);
0762 break;
0763 default:
0764 err = -1;
0765 p_err("unexpected object type: %d", type);
0766 goto err_free;
0767 }
0768 if (err) {
0769 if (errno == ENOENT) {
0770 err = 0;
0771 break;
0772 }
0773 p_err("can't get next %s: %s%s", names[type],
0774 strerror(errno),
0775 errno == EINVAL ? " -- kernel too old?" : "");
0776 goto err_free;
0777 }
0778
0779 switch (type) {
0780 case BPF_OBJ_PROG:
0781 fd = bpf_prog_get_fd_by_id(id);
0782 break;
0783 case BPF_OBJ_MAP:
0784 fd = bpf_map_get_fd_by_id(id);
0785 break;
0786 default:
0787 err = -1;
0788 p_err("unexpected object type: %d", type);
0789 goto err_free;
0790 }
0791 if (fd < 0) {
0792 if (errno == ENOENT)
0793 continue;
0794 p_err("can't get %s by id (%u): %s", names[type], id,
0795 strerror(errno));
0796 err = -1;
0797 goto err_free;
0798 }
0799
0800 memset(info, 0, *len);
0801 err = bpf_obj_get_info_by_fd(fd, info, len);
0802 close(fd);
0803 if (err) {
0804 p_err("can't get %s info: %s", names[type],
0805 strerror(errno));
0806 goto err_free;
0807 }
0808
0809 switch (type) {
0810 case BPF_OBJ_PROG:
0811 btf_id = ((struct bpf_prog_info *)info)->btf_id;
0812 break;
0813 case BPF_OBJ_MAP:
0814 btf_id = ((struct bpf_map_info *)info)->btf_id;
0815 break;
0816 default:
0817 err = -1;
0818 p_err("unexpected object type: %d", type);
0819 goto err_free;
0820 }
0821 if (!btf_id)
0822 continue;
0823
0824 err = hashmap__append(tab, u32_as_hash_field(btf_id),
0825 u32_as_hash_field(id));
0826 if (err) {
0827 p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s",
0828 btf_id, id, strerror(errno));
0829 goto err_free;
0830 }
0831 }
0832
0833 return 0;
0834
0835 err_free:
0836 hashmap__free(tab);
0837 return err;
0838 }
0839
0840 static int
0841 build_btf_tables(struct hashmap *btf_prog_table,
0842 struct hashmap *btf_map_table)
0843 {
0844 struct bpf_prog_info prog_info;
0845 __u32 prog_len = sizeof(prog_info);
0846 struct bpf_map_info map_info;
0847 __u32 map_len = sizeof(map_info);
0848 int err = 0;
0849
0850 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
0851 &prog_len);
0852 if (err)
0853 return err;
0854
0855 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
0856 &map_len);
0857 if (err) {
0858 hashmap__free(btf_prog_table);
0859 return err;
0860 }
0861
0862 return 0;
0863 }
0864
0865 static void
0866 show_btf_plain(struct bpf_btf_info *info, int fd,
0867 struct hashmap *btf_prog_table,
0868 struct hashmap *btf_map_table)
0869 {
0870 struct hashmap_entry *entry;
0871 const char *name = u64_to_ptr(info->name);
0872 int n;
0873
0874 printf("%u: ", info->id);
0875 if (info->kernel_btf)
0876 printf("name [%s] ", name);
0877 else if (name && name[0])
0878 printf("name %s ", name);
0879 else
0880 printf("name <anon> ");
0881 printf("size %uB", info->btf_size);
0882
0883 n = 0;
0884 hashmap__for_each_key_entry(btf_prog_table, entry,
0885 u32_as_hash_field(info->id)) {
0886 printf("%s%u", n++ == 0 ? " prog_ids " : ",",
0887 hash_field_as_u32(entry->value));
0888 }
0889
0890 n = 0;
0891 hashmap__for_each_key_entry(btf_map_table, entry,
0892 u32_as_hash_field(info->id)) {
0893 printf("%s%u", n++ == 0 ? " map_ids " : ",",
0894 hash_field_as_u32(entry->value));
0895 }
0896
0897 emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
0898
0899 printf("\n");
0900 }
0901
0902 static void
0903 show_btf_json(struct bpf_btf_info *info, int fd,
0904 struct hashmap *btf_prog_table,
0905 struct hashmap *btf_map_table)
0906 {
0907 struct hashmap_entry *entry;
0908 const char *name = u64_to_ptr(info->name);
0909
0910 jsonw_start_object(json_wtr);
0911 jsonw_uint_field(json_wtr, "id", info->id);
0912 jsonw_uint_field(json_wtr, "size", info->btf_size);
0913
0914 jsonw_name(json_wtr, "prog_ids");
0915 jsonw_start_array(json_wtr);
0916 hashmap__for_each_key_entry(btf_prog_table, entry,
0917 u32_as_hash_field(info->id)) {
0918 jsonw_uint(json_wtr, hash_field_as_u32(entry->value));
0919 }
0920 jsonw_end_array(json_wtr);
0921
0922 jsonw_name(json_wtr, "map_ids");
0923 jsonw_start_array(json_wtr);
0924 hashmap__for_each_key_entry(btf_map_table, entry,
0925 u32_as_hash_field(info->id)) {
0926 jsonw_uint(json_wtr, hash_field_as_u32(entry->value));
0927 }
0928 jsonw_end_array(json_wtr);
0929
0930 emit_obj_refs_json(refs_table, info->id, json_wtr);
0931
0932 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
0933
0934 if (name && name[0])
0935 jsonw_string_field(json_wtr, "name", name);
0936
0937 jsonw_end_object(json_wtr);
0938 }
0939
0940 static int
0941 show_btf(int fd, struct hashmap *btf_prog_table,
0942 struct hashmap *btf_map_table)
0943 {
0944 struct bpf_btf_info info;
0945 __u32 len = sizeof(info);
0946 char name[64];
0947 int err;
0948
0949 memset(&info, 0, sizeof(info));
0950 err = bpf_obj_get_info_by_fd(fd, &info, &len);
0951 if (err) {
0952 p_err("can't get BTF object info: %s", strerror(errno));
0953 return -1;
0954 }
0955
0956 if (info.name_len) {
0957 memset(&info, 0, sizeof(info));
0958 info.name_len = sizeof(name);
0959 info.name = ptr_to_u64(name);
0960 len = sizeof(info);
0961
0962 err = bpf_obj_get_info_by_fd(fd, &info, &len);
0963 if (err) {
0964 p_err("can't get BTF object info: %s", strerror(errno));
0965 return -1;
0966 }
0967 }
0968
0969 if (json_output)
0970 show_btf_json(&info, fd, btf_prog_table, btf_map_table);
0971 else
0972 show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
0973
0974 return 0;
0975 }
0976
0977 static int do_show(int argc, char **argv)
0978 {
0979 struct hashmap *btf_prog_table;
0980 struct hashmap *btf_map_table;
0981 int err, fd = -1;
0982 __u32 id = 0;
0983
0984 if (argc == 2) {
0985 fd = btf_parse_fd(&argc, &argv);
0986 if (fd < 0)
0987 return -1;
0988 }
0989
0990 if (argc) {
0991 if (fd >= 0)
0992 close(fd);
0993 return BAD_ARG();
0994 }
0995
0996 btf_prog_table = hashmap__new(hash_fn_for_key_as_id,
0997 equal_fn_for_key_as_id, NULL);
0998 btf_map_table = hashmap__new(hash_fn_for_key_as_id,
0999 equal_fn_for_key_as_id, NULL);
1000 if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) {
1001 hashmap__free(btf_prog_table);
1002 hashmap__free(btf_map_table);
1003 if (fd >= 0)
1004 close(fd);
1005 p_err("failed to create hashmap for object references");
1006 return -1;
1007 }
1008 err = build_btf_tables(btf_prog_table, btf_map_table);
1009 if (err) {
1010 if (fd >= 0)
1011 close(fd);
1012 return err;
1013 }
1014 build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
1015
1016 if (fd >= 0) {
1017 err = show_btf(fd, btf_prog_table, btf_map_table);
1018 close(fd);
1019 goto exit_free;
1020 }
1021
1022 if (json_output)
1023 jsonw_start_array(json_wtr);
1024
1025 while (true) {
1026 err = bpf_btf_get_next_id(id, &id);
1027 if (err) {
1028 if (errno == ENOENT) {
1029 err = 0;
1030 break;
1031 }
1032 p_err("can't get next BTF object: %s%s",
1033 strerror(errno),
1034 errno == EINVAL ? " -- kernel too old?" : "");
1035 err = -1;
1036 break;
1037 }
1038
1039 fd = bpf_btf_get_fd_by_id(id);
1040 if (fd < 0) {
1041 if (errno == ENOENT)
1042 continue;
1043 p_err("can't get BTF object by id (%u): %s",
1044 id, strerror(errno));
1045 err = -1;
1046 break;
1047 }
1048
1049 err = show_btf(fd, btf_prog_table, btf_map_table);
1050 close(fd);
1051 if (err)
1052 break;
1053 }
1054
1055 if (json_output)
1056 jsonw_end_array(json_wtr);
1057
1058 exit_free:
1059 hashmap__free(btf_prog_table);
1060 hashmap__free(btf_map_table);
1061 delete_obj_refs_table(refs_table);
1062
1063 return err;
1064 }
1065
1066 static int do_help(int argc, char **argv)
1067 {
1068 if (json_output) {
1069 jsonw_null(json_wtr);
1070 return 0;
1071 }
1072
1073 fprintf(stderr,
1074 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
1075 " %1$s %2$s dump BTF_SRC [format FORMAT]\n"
1076 " %1$s %2$s help\n"
1077 "\n"
1078 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
1079 " FORMAT := { raw | c }\n"
1080 " " HELP_SPEC_MAP "\n"
1081 " " HELP_SPEC_PROGRAM "\n"
1082 " " HELP_SPEC_OPTIONS " |\n"
1083 " {-B|--base-btf} }\n"
1084 "",
1085 bin_name, "btf");
1086
1087 return 0;
1088 }
1089
1090 static const struct cmd cmds[] = {
1091 { "show", do_show },
1092 { "list", do_show },
1093 { "help", do_help },
1094 { "dump", do_dump },
1095 { 0 }
1096 };
1097
1098 int do_btf(int argc, char **argv)
1099 {
1100 return cmd_select(cmds, argc, argv, do_help);
1101 }
