#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <errno.h>
#include <fcntl.h>
#include <linux/err.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <linux/btf.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/hashmap.h>
#include <bpf/libbpf.h>
#include "json_writer.h"
#include "main.h"
#define KFUNC_DECL_TAG "bpf_kfunc"
#define FASTCALL_DECL_TAG "bpf_fastcall"
#define MAX_ROOT_IDS 16
static const char * const btf_kind_str[NR_BTF_KINDS] = {
[BTF_KIND_UNKN] = "UNKNOWN",
[BTF_KIND_INT] = "INT",
[BTF_KIND_PTR] = "PTR",
[BTF_KIND_ARRAY] = "ARRAY",
[BTF_KIND_STRUCT] = "STRUCT",
[BTF_KIND_UNION] = "UNION",
[BTF_KIND_ENUM] = "ENUM",
[BTF_KIND_FWD] = "FWD",
[BTF_KIND_TYPEDEF] = "TYPEDEF",
[BTF_KIND_VOLATILE] = "VOLATILE",
[BTF_KIND_CONST] = "CONST",
[BTF_KIND_RESTRICT] = "RESTRICT",
[BTF_KIND_FUNC] = "FUNC",
[BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
[BTF_KIND_VAR] = "VAR",
[BTF_KIND_DATASEC] = "DATASEC",
[BTF_KIND_FLOAT] = "FLOAT",
[BTF_KIND_DECL_TAG] = "DECL_TAG",
[BTF_KIND_TYPE_TAG] = "TYPE_TAG",
[BTF_KIND_ENUM64] = "ENUM64",
};
struct sort_datum {
int index;
int type_rank;
const char *sort_name;
const char *own_name;
__u64 disambig_hash;
};
static const char *btf_int_enc_str(__u8 encoding)
{
switch (encoding) {
case 0:
return "(none)";
case BTF_INT_SIGNED:
return "SIGNED";
case BTF_INT_CHAR:
return "CHAR";
case BTF_INT_BOOL:
return "BOOL";
default:
return "UNKN";
}
}
static const char *btf_var_linkage_str(__u32 linkage)
{
switch (linkage) {
case BTF_VAR_STATIC:
return "static";
case BTF_VAR_GLOBAL_ALLOCATED:
return "global";
case BTF_VAR_GLOBAL_EXTERN:
return "extern";
default:
return "(unknown)";
}
}
static const char *btf_func_linkage_str(const struct btf_type *t)
{
switch (btf_vlen(t)) {
case BTF_FUNC_STATIC:
return "static";
case BTF_FUNC_GLOBAL:
return "global";
case BTF_FUNC_EXTERN:
return "extern";
default:
return "(unknown)";
}
}
static const char *btf_str(const struct btf *btf, __u32 off)
{
if (!off)
return "(anon)";
return btf__name_by_offset(btf, off) ? : "(invalid)";
}
static int btf_kind_safe(int kind)
{
return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
}
static int dump_btf_type(const struct btf *btf, __u32 id,
const struct btf_type *t)
{
json_writer_t *w = json_wtr;
int kind = btf_kind(t);
if (json_output) {
jsonw_start_object(w);
jsonw_uint_field(w, "id", id);
jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
jsonw_string_field(w, "name", btf_str(btf, t->name_off));
} else {
printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
btf_str(btf, t->name_off));
}
switch (kind) {
case BTF_KIND_INT: {
__u32 v = *(__u32 *)(t + 1);
const char *enc;
enc = btf_int_enc_str(BTF_INT_ENCODING(v));
if (json_output) {
jsonw_uint_field(w, "size", t->size);
jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
jsonw_string_field(w, "encoding", enc);
} else {
printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
enc);
}
break;
}
case BTF_KIND_PTR:
case BTF_KIND_CONST:
case BTF_KIND_VOLATILE:
case BTF_KIND_RESTRICT:
case BTF_KIND_TYPEDEF:
case BTF_KIND_TYPE_TAG:
if (json_output)
jsonw_uint_field(w, "type_id", t->type);
else
printf(" type_id=%u", t->type);
break;
case BTF_KIND_ARRAY: {
const struct btf_array *arr = (const void *)(t + 1);
if (json_output) {
jsonw_uint_field(w, "type_id", arr->type);
jsonw_uint_field(w, "index_type_id", arr->index_type);
jsonw_uint_field(w, "nr_elems", arr->nelems);
} else {
printf(" type_id=%u index_type_id=%u nr_elems=%u",
arr->type, arr->index_type, arr->nelems);
}
break;
}
case BTF_KIND_STRUCT:
case BTF_KIND_UNION: {
const struct btf_member *m = (const void *)(t + 1);
__u16 vlen = BTF_INFO_VLEN(t->info);
int i;
if (json_output) {
jsonw_uint_field(w, "size", t->size);
jsonw_uint_field(w, "vlen", vlen);
jsonw_name(w, "members");
jsonw_start_array(w);
} else {
printf(" size=%u vlen=%u", t->size, vlen);
}
for (i = 0; i < vlen; i++, m++) {
const char *name = btf_str(btf, m->name_off);
__u32 bit_off, bit_sz;
if (BTF_INFO_KFLAG(t->info)) {
bit_off = BTF_MEMBER_BIT_OFFSET(m->offset);
bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset);
} else {
bit_off = m->offset;
bit_sz = 0;
}
if (json_output) {
jsonw_start_object(w);
jsonw_string_field(w, "name", name);
jsonw_uint_field(w, "type_id", m->type);
jsonw_uint_field(w, "bits_offset", bit_off);
if (bit_sz) {
jsonw_uint_field(w, "bitfield_size",
bit_sz);
}
jsonw_end_object(w);
} else {
printf("\n\t'%s' type_id=%u bits_offset=%u",
name, m->type, bit_off);
if (bit_sz)
printf(" bitfield_size=%u", bit_sz);
}
}
if (json_output)
jsonw_end_array(w);
break;
}
case BTF_KIND_ENUM: {
const struct btf_enum *v = (const void *)(t + 1);
__u16 vlen = BTF_INFO_VLEN(t->info);
const char *encoding;
int i;
encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
if (json_output) {
jsonw_string_field(w, "encoding", encoding);
jsonw_uint_field(w, "size", t->size);
jsonw_uint_field(w, "vlen", vlen);
jsonw_name(w, "values");
jsonw_start_array(w);
} else {
printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
}
for (i = 0; i < vlen; i++, v++) {
const char *name = btf_str(btf, v->name_off);
if (json_output) {
jsonw_start_object(w);
jsonw_string_field(w, "name", name);
if (btf_kflag(t))
jsonw_int_field(w, "val", v->val);
else
jsonw_uint_field(w, "val", v->val);
jsonw_end_object(w);
} else {
if (btf_kflag(t))
printf("\n\t'%s' val=%d", name, v->val);
else
printf("\n\t'%s' val=%u", name, (__u32)v->val);
}
}
if (json_output)
jsonw_end_array(w);
break;
}
case BTF_KIND_ENUM64: {
const struct btf_enum64 *v = btf_enum64(t);
__u16 vlen = btf_vlen(t);
const char *encoding;
int i;
encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
if (json_output) {
jsonw_string_field(w, "encoding", encoding);
jsonw_uint_field(w, "size", t->size);
jsonw_uint_field(w, "vlen", vlen);
jsonw_name(w, "values");
jsonw_start_array(w);
} else {
printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
}
for (i = 0; i < vlen; i++, v++) {
const char *name = btf_str(btf, v->name_off);
__u64 val = ((__u64)v->val_hi32 << 32) | v->val_lo32;
if (json_output) {
jsonw_start_object(w);
jsonw_string_field(w, "name", name);
if (btf_kflag(t))
jsonw_int_field(w, "val", val);
else
jsonw_uint_field(w, "val", val);
jsonw_end_object(w);
} else {
if (btf_kflag(t))
printf("\n\t'%s' val=%lldLL", name,
(long long)val);
else
printf("\n\t'%s' val=%lluULL", name,
(unsigned long long)val);
}
}
if (json_output)
jsonw_end_array(w);
break;
}
case BTF_KIND_FWD: {
const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union"
: "struct";
if (json_output)
jsonw_string_field(w, "fwd_kind", fwd_kind);
else
printf(" fwd_kind=%s", fwd_kind);
break;
}
case BTF_KIND_FUNC: {
const char *linkage = btf_func_linkage_str(t);
if (json_output) {
jsonw_uint_field(w, "type_id", t->type);
jsonw_string_field(w, "linkage", linkage);
} else {
printf(" type_id=%u linkage=%s", t->type, linkage);
}
break;
}
case BTF_KIND_FUNC_PROTO: {
const struct btf_param *p = (const void *)(t + 1);
__u16 vlen = BTF_INFO_VLEN(t->info);
int i;
if (json_output) {
jsonw_uint_field(w, "ret_type_id", t->type);
jsonw_uint_field(w, "vlen", vlen);
jsonw_name(w, "params");
jsonw_start_array(w);
} else {
printf(" ret_type_id=%u vlen=%u", t->type, vlen);
}
for (i = 0; i < vlen; i++, p++) {
const char *name = btf_str(btf, p->name_off);
if (json_output) {
jsonw_start_object(w);
jsonw_string_field(w, "name", name);
jsonw_uint_field(w, "type_id", p->type);
jsonw_end_object(w);
} else {
printf("\n\t'%s' type_id=%u", name, p->type);
}
}
if (json_output)
jsonw_end_array(w);
break;
}
case BTF_KIND_VAR: {
const struct btf_var *v = (const void *)(t + 1);
const char *linkage;
linkage = btf_var_linkage_str(v->linkage);
if (json_output) {
jsonw_uint_field(w, "type_id", t->type);
jsonw_string_field(w, "linkage", linkage);
} else {
printf(" type_id=%u, linkage=%s", t->type, linkage);
}
break;
}
case BTF_KIND_DATASEC: {
const struct btf_var_secinfo *v = (const void *)(t + 1);
const struct btf_type *vt;
__u16 vlen = BTF_INFO_VLEN(t->info);
int i;
if (json_output) {
jsonw_uint_field(w, "size", t->size);
jsonw_uint_field(w, "vlen", vlen);
jsonw_name(w, "vars");
jsonw_start_array(w);
} else {
printf(" size=%u vlen=%u", t->size, vlen);
}
for (i = 0; i < vlen; i++, v++) {
if (json_output) {
jsonw_start_object(w);
jsonw_uint_field(w, "type_id", v->type);
jsonw_uint_field(w, "offset", v->offset);
jsonw_uint_field(w, "size", v->size);
jsonw_end_object(w);
} else {
printf("\n\ttype_id=%u offset=%u size=%u",
v->type, v->offset, v->size);
if (v->type < btf__type_cnt(btf)) {
vt = btf__type_by_id(btf, v->type);
printf(" (%s '%s')",
btf_kind_str[btf_kind_safe(btf_kind(vt))],
btf_str(btf, vt->name_off));
}
}
}
if (json_output)
jsonw_end_array(w);
break;
}
case BTF_KIND_FLOAT: {
if (json_output)
jsonw_uint_field(w, "size", t->size);
else
printf(" size=%u", t->size);
break;
}
case BTF_KIND_DECL_TAG: {
const struct btf_decl_tag *tag = (const void *)(t + 1);
if (json_output) {
jsonw_uint_field(w, "type_id", t->type);
jsonw_int_field(w, "component_idx", tag->component_idx);
} else {
printf(" type_id=%u component_idx=%d", t->type, tag->component_idx);
}
break;
}
default:
break;
}
if (json_output)
jsonw_end_object(json_wtr);
else
printf("\n");
return 0;
}
static int dump_btf_raw(const struct btf *btf,
__u32 *root_type_ids, int root_type_cnt)
{
const struct btf_type *t;
int i;
if (json_output) {
jsonw_start_object(json_wtr);
jsonw_name(json_wtr, "types");
jsonw_start_array(json_wtr);
}
if (root_type_cnt) {
for (i = 0; i < root_type_cnt; i++) {
t = btf__type_by_id(btf, root_type_ids[i]);
dump_btf_type(btf, root_type_ids[i], t);
}
} else {
const struct btf *base;
int cnt = btf__type_cnt(btf);
int start_id = 1;
base = btf__base_btf(btf);
if (base)
start_id = btf__type_cnt(base);
for (i = start_id; i < cnt; i++) {
t = btf__type_by_id(btf, i);
dump_btf_type(btf, i, t);
}
}
if (json_output) {
jsonw_end_array(json_wtr);
jsonw_end_object(json_wtr);
}
return 0;
}
struct ptr_array {
__u32 cnt;
__u32 cap;
const void **elems;
};
static int ptr_array_push(const void *ptr, struct ptr_array *arr)
{
__u32 new_cap;
void *tmp;
if (arr->cnt == arr->cap) {
new_cap = (arr->cap ?: 16) * 2;
tmp = realloc(arr->elems, sizeof(*arr->elems) * new_cap);
if (!tmp)
return -ENOMEM;
arr->elems = tmp;
arr->cap = new_cap;
}
arr->elems[arr->cnt++] = ptr;
return 0;
}
static void ptr_array_free(struct ptr_array *arr)
{
free(arr->elems);
}
static int cmp_kfuncs(const void *pa, const void *pb, void *ctx)
{
struct btf *btf = ctx;
const struct btf_type *a = *(void **)pa;
const struct btf_type *b = *(void **)pb;
return strcmp(btf__str_by_offset(btf, a->name_off),
btf__str_by_offset(btf, b->name_off));
}
static int dump_btf_kfuncs(struct btf_dump *d, const struct btf *btf)
{
LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts);
__u32 cnt = btf__type_cnt(btf), i, j;
struct ptr_array fastcalls = {};
struct ptr_array kfuncs = {};
int err = 0;
printf("\n/* BPF kfuncs */\n");
printf("#ifndef BPF_NO_KFUNC_PROTOTYPES\n");
for (i = 1; i < cnt; i++) {
const struct btf_type *t = btf__type_by_id(btf, i);
const struct btf_type *ft;
const char *name;
if (!btf_is_decl_tag(t))
continue;
if (btf_decl_tag(t)->component_idx != -1)
continue;
ft = btf__type_by_id(btf, t->type);
if (!btf_is_func(ft))
continue;
name = btf__name_by_offset(btf, t->name_off);
if (strncmp(name, KFUNC_DECL_TAG, sizeof(KFUNC_DECL_TAG)) == 0) {
err = ptr_array_push(ft, &kfuncs);
if (err)
goto out;
}
if (strncmp(name, FASTCALL_DECL_TAG, sizeof(FASTCALL_DECL_TAG)) == 0) {
err = ptr_array_push(ft, &fastcalls);
if (err)
goto out;
}
}
qsort_r(kfuncs.elems, kfuncs.cnt, sizeof(*kfuncs.elems), cmp_kfuncs, (void *)btf);
for (i = 0; i < kfuncs.cnt; i++) {
const struct btf_type *t = kfuncs.elems[i];
printf("extern ");
for (j = 0; j < fastcalls.cnt; j++) {
if (fastcalls.elems[j] == t) {
printf("__bpf_fastcall ");
break;
}
}
opts.field_name = btf__name_by_offset(btf, t->name_off);
err = btf_dump__emit_type_decl(d, t->type, &opts);
if (err)
goto out;
printf(" __weak __ksym;\n");
}
printf("#endif\n\n");
out:
ptr_array_free(&fastcalls);
ptr_array_free(&kfuncs);
return err;
}
static void __printf(2, 0) btf_dump_printf(void *ctx,
const char *fmt, va_list args)
{
vfprintf(stdout, fmt, args);
}
static int btf_type_rank(const struct btf *btf, __u32 index, bool has_name)
{
const struct btf_type *t = btf__type_by_id(btf, index);
const int kind = btf_kind(t);
const int max_rank = 10;
if (t->name_off)
has_name = true;
switch (kind) {
case BTF_KIND_ENUM:
case BTF_KIND_ENUM64:
return has_name ? 1 : 0;
case BTF_KIND_INT:
case BTF_KIND_FLOAT:
return 2;
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
return has_name ? 3 : max_rank;
case BTF_KIND_FUNC_PROTO:
return has_name ? 4 : max_rank;
case BTF_KIND_ARRAY:
if (has_name)
return btf_type_rank(btf, btf_array(t)->type, has_name);
return max_rank;
case BTF_KIND_TYPE_TAG:
case BTF_KIND_CONST:
case BTF_KIND_PTR:
case BTF_KIND_VOLATILE:
case BTF_KIND_RESTRICT:
case BTF_KIND_TYPEDEF:
case BTF_KIND_DECL_TAG:
if (has_name)
return btf_type_rank(btf, t->type, has_name);
return max_rank;
default:
return max_rank;
}
}
static const char *btf_type_sort_name(const struct btf *btf, __u32 index, bool from_ref)
{
const struct btf_type *t = btf__type_by_id(btf, index);
switch (btf_kind(t)) {
case BTF_KIND_ENUM:
case BTF_KIND_ENUM64: {
int name_off = t->name_off;
if (!from_ref && !name_off && btf_vlen(t))
name_off = btf_kind(t) == BTF_KIND_ENUM64 ?
btf_enum64(t)->name_off :
btf_enum(t)->name_off;
return btf__name_by_offset(btf, name_off);
}
case BTF_KIND_ARRAY:
return btf_type_sort_name(btf, btf_array(t)->type, true);
case BTF_KIND_TYPE_TAG:
case BTF_KIND_CONST:
case BTF_KIND_PTR:
case BTF_KIND_VOLATILE:
case BTF_KIND_RESTRICT:
case BTF_KIND_TYPEDEF:
case BTF_KIND_DECL_TAG:
return btf_type_sort_name(btf, t->type, true);
default:
return btf__name_by_offset(btf, t->name_off);
}
return NULL;
}
static __u64 hasher(__u64 hash, __u64 val)
{
return hash * 31 + val;
}
static __u64 btf_name_hasher(__u64 hash, const struct btf *btf, __u32 name_off)
{
if (!name_off)
return hash;
return hasher(hash, str_hash(btf__name_by_offset(btf, name_off)));
}
static __u64 btf_type_disambig_hash(const struct btf *btf, __u32 id, bool include_members)
{
const struct btf_type *t = btf__type_by_id(btf, id);
int i;
size_t hash = 0;
hash = btf_name_hasher(hash, btf, t->name_off);
switch (btf_kind(t)) {
case BTF_KIND_ENUM:
case BTF_KIND_ENUM64:
for (i = 0; i < btf_vlen(t); i++) {
__u32 name_off = btf_is_enum(t) ?
btf_enum(t)[i].name_off :
btf_enum64(t)[i].name_off;
hash = btf_name_hasher(hash, btf, name_off);
}
break;
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
if (!include_members)
break;
for (i = 0; i < btf_vlen(t); i++) {
const struct btf_member *m = btf_members(t) + i;
hash = btf_name_hasher(hash, btf, m->name_off);
hash = hasher(hash, btf_type_disambig_hash(btf, m->type, false));
}
break;
case BTF_KIND_TYPE_TAG:
case BTF_KIND_CONST:
case BTF_KIND_PTR:
case BTF_KIND_VOLATILE:
case BTF_KIND_RESTRICT:
case BTF_KIND_TYPEDEF:
case BTF_KIND_DECL_TAG:
hash = hasher(hash, btf_type_disambig_hash(btf, t->type, include_members));
break;
case BTF_KIND_ARRAY: {
struct btf_array *arr = btf_array(t);
hash = hasher(hash, arr->nelems);
hash = hasher(hash, btf_type_disambig_hash(btf, arr->type, include_members));
break;
}
default:
break;
}
return hash;
}
static int btf_type_compare(const void *left, const void *right)
{
const struct sort_datum *d1 = (const struct sort_datum *)left;
const struct sort_datum *d2 = (const struct sort_datum *)right;
int r;
r = d1->type_rank - d2->type_rank;
r = r ?: strcmp(d1->sort_name, d2->sort_name);
r = r ?: strcmp(d1->own_name, d2->own_name);
if (r)
return r;
if (d1->disambig_hash != d2->disambig_hash)
return d1->disambig_hash < d2->disambig_hash ? -1 : 1;
return d1->index - d2->index;
}
static struct sort_datum *sort_btf_c(const struct btf *btf)
{
struct sort_datum *datums;
int n;
n = btf__type_cnt(btf);
datums = malloc(sizeof(struct sort_datum) * n);
if (!datums)
return NULL;
for (int i = 0; i < n; ++i) {
struct sort_datum *d = datums + i;
const struct btf_type *t = btf__type_by_id(btf, i);
d->index = i;
d->type_rank = btf_type_rank(btf, i, false);
d->sort_name = btf_type_sort_name(btf, i, false);
d->own_name = btf__name_by_offset(btf, t->name_off);
d->disambig_hash = btf_type_disambig_hash(btf, i, true);
}
qsort(datums, n, sizeof(struct sort_datum), btf_type_compare);
return datums;
}
static int dump_btf_c(const struct btf *btf,
__u32 *root_type_ids, int root_type_cnt, bool sort_dump)
{
struct sort_datum *datums = NULL;
struct btf_dump *d;
int err = 0, i;
d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);
if (!d)
return -errno;
printf("#ifndef __VMLINUX_H__\n");
printf("#define __VMLINUX_H__\n");
printf("\n");
printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
printf("#endif\n\n");
printf("#ifndef __ksym\n");
printf("#define __ksym __attribute__((section(\".ksyms\")))\n");
printf("#endif\n\n");
printf("#ifndef __weak\n");
printf("#define __weak __attribute__((weak))\n");
printf("#endif\n\n");
printf("#ifndef __bpf_fastcall\n");
printf("#if __has_attribute(bpf_fastcall)\n");
printf("#define __bpf_fastcall __attribute__((bpf_fastcall))\n");
printf("#else\n");
printf("#define __bpf_fastcall\n");
printf("#endif\n");
printf("#endif\n\n");
if (root_type_cnt) {
for (i = 0; i < root_type_cnt; i++) {
err = btf_dump__dump_type(d, root_type_ids[i]);
if (err)
goto done;
}
} else {
int cnt = btf__type_cnt(btf);
if (sort_dump)
datums = sort_btf_c(btf);
for (i = 1; i < cnt; i++) {
int idx = datums ? datums[i].index : i;
err = btf_dump__dump_type(d, idx);
if (err)
goto done;
}
err = dump_btf_kfuncs(d, btf);
if (err)
goto done;
}
printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
printf("#pragma clang attribute pop\n");
printf("#endif\n");
printf("\n");
printf("#endif /* __VMLINUX_H__ */\n");
done:
free(datums);
btf_dump__free(d);
return err;
}
static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
static struct btf *get_vmlinux_btf_from_sysfs(void)
{
struct btf *base;
base = btf__parse(sysfs_vmlinux, NULL);
if (!base)
p_err("failed to parse vmlinux BTF at '%s': %d\n",
sysfs_vmlinux, -errno);
return base;
}
#define BTF_NAME_BUFF_LEN 64
static bool btf_is_kernel_module(__u32 btf_id)
{
struct bpf_btf_info btf_info = {};
char btf_name[BTF_NAME_BUFF_LEN];
int btf_fd;
__u32 len;
int err;
btf_fd = bpf_btf_get_fd_by_id(btf_id);
if (btf_fd < 0) {
p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno));
return false;
}
len = sizeof(btf_info);
btf_info.name = ptr_to_u64(btf_name);
btf_info.name_len = sizeof(btf_name);
err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len);
close(btf_fd);
if (err) {
p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno));
return false;
}
return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0;
}
static int do_dump(int argc, char **argv)
{
bool dump_c = false, sort_dump_c = true;
struct btf *btf = NULL, *base = NULL;
__u32 root_type_ids[MAX_ROOT_IDS];
bool have_id_filtering;
int root_type_cnt = 0;
__u32 btf_id = -1;
const char *src;
int fd = -1;
int err = 0;
int i;
if (!REQ_ARGS(2)) {
usage();
return -1;
}
src = GET_ARG();
if (is_prefix(src, "map")) {
struct bpf_map_info info = {};
__u32 len = sizeof(info);
if (!REQ_ARGS(2)) {
usage();
return -1;
}
fd = map_parse_fd_and_info(&argc, &argv, &info, &len,
BPF_F_RDONLY);
if (fd < 0)
return -1;
btf_id = info.btf_id;
if (argc && is_prefix(*argv, "key")) {
root_type_ids[root_type_cnt++] = info.btf_key_type_id;
NEXT_ARG();
} else if (argc && is_prefix(*argv, "value")) {
root_type_ids[root_type_cnt++] = info.btf_value_type_id;
NEXT_ARG();
} else if (argc && is_prefix(*argv, "all")) {
NEXT_ARG();
} else if (argc && is_prefix(*argv, "kv")) {
root_type_ids[root_type_cnt++] = info.btf_key_type_id;
root_type_ids[root_type_cnt++] = info.btf_value_type_id;
NEXT_ARG();
} else {
root_type_ids[root_type_cnt++] = info.btf_key_type_id;
root_type_ids[root_type_cnt++] = info.btf_value_type_id;
}
} else if (is_prefix(src, "prog")) {
struct bpf_prog_info info = {};
__u32 len = sizeof(info);
if (!REQ_ARGS(2)) {
usage();
return -1;
}
fd = prog_parse_fd(&argc, &argv);
if (fd < 0)
return -1;
err = bpf_prog_get_info_by_fd(fd, &info, &len);
if (err) {
p_err("can't get prog info: %s", strerror(errno));
goto done;
}
btf_id = info.btf_id;
} else if (is_prefix(src, "id")) {
char *endptr;
btf_id = strtoul(*argv, &endptr, 0);
if (*endptr) {
p_err("can't parse %s as ID", *argv);
return -1;
}
NEXT_ARG();
} else if (is_prefix(src, "file")) {
const char sysfs_prefix[] = "/sys/kernel/btf/";
if (!base_btf &&
strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
strcmp(*argv, sysfs_vmlinux) != 0)
base = get_vmlinux_btf_from_sysfs();
btf = btf__parse_split(*argv, base ?: base_btf);
if (!btf) {
err = -errno;
p_err("failed to load BTF from %s: %s",
*argv, strerror(errno));
goto done;
}
NEXT_ARG();
} else {
err = -1;
p_err("unrecognized BTF source specifier: '%s'", src);
goto done;
}
have_id_filtering = !!root_type_cnt;
while (argc) {
if (is_prefix(*argv, "format")) {
NEXT_ARG();
if (argc < 1) {
p_err("expecting value for 'format' option\n");
err = -EINVAL;
goto done;
}
if (strcmp(*argv, "c") == 0) {
dump_c = true;
} else if (strcmp(*argv, "raw") == 0) {
dump_c = false;
} else {
p_err("unrecognized format specifier: '%s', possible values: raw, c",
*argv);
err = -EINVAL;
goto done;
}
NEXT_ARG();
} else if (is_prefix(*argv, "root_id")) {
__u32 root_id;
char *end;
if (have_id_filtering) {
p_err("cannot use root_id with other type filtering");
err = -EINVAL;
goto done;
} else if (root_type_cnt == MAX_ROOT_IDS) {
p_err("only %d root_id are supported", MAX_ROOT_IDS);
err = -E2BIG;
goto done;
}
NEXT_ARG();
root_id = strtoul(*argv, &end, 0);
if (*end) {
err = -1;
p_err("can't parse %s as root ID", *argv);
goto done;
}
for (i = 0; i < root_type_cnt; i++) {
if (root_type_ids[i] == root_id) {
err = -EINVAL;
p_err("duplicate root_id %u supplied", root_id);
goto done;
}
}
root_type_ids[root_type_cnt++] = root_id;
NEXT_ARG();
} else if (is_prefix(*argv, "unsorted")) {
sort_dump_c = false;
NEXT_ARG();
} else {
p_err("unrecognized option: '%s'", *argv);
err = -EINVAL;
goto done;
}
}
if (!btf) {
if (!base_btf && btf_is_kernel_module(btf_id)) {
p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)",
sysfs_vmlinux);
base_btf = get_vmlinux_btf_from_sysfs();
}
btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
if (!btf) {
err = -errno;
p_err("get btf by id (%u): %s", btf_id, strerror(errno));
goto done;
}
}
for (i = 0; i < root_type_cnt; i++) {
if (root_type_ids[i] >= btf__type_cnt(btf)) {
err = -EINVAL;
p_err("invalid root ID: %u", root_type_ids[i]);
goto done;
}
}
if (dump_c) {
if (json_output) {
p_err("JSON output for C-syntax dump is not supported");
err = -ENOTSUP;
goto done;
}
err = dump_btf_c(btf, root_type_ids, root_type_cnt, sort_dump_c);
} else {
err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
}
done:
close(fd);
btf__free(btf);
btf__free(base);
return err;
}
static int btf_parse_fd(int *argc, char ***argv)
{
unsigned int id;
char *endptr;
int fd;
if (!is_prefix(*argv[0], "id")) {
p_err("expected 'id', got: '%s'?", **argv);
return -1;
}
NEXT_ARGP();
id = strtoul(**argv, &endptr, 0);
if (*endptr) {
p_err("can't parse %s as ID", **argv);
return -1;
}
NEXT_ARGP();
fd = bpf_btf_get_fd_by_id(id);
if (fd < 0)
p_err("can't get BTF object by id (%u): %s",
id, strerror(errno));
return fd;
}
static int
build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type,
void *info, __u32 *len)
{
static const char * const names[] = {
[BPF_OBJ_UNKNOWN] = "unknown",
[BPF_OBJ_PROG] = "prog",
[BPF_OBJ_MAP] = "map",
};
LIBBPF_OPTS(bpf_get_fd_by_id_opts, opts_ro);
__u32 btf_id, id = 0;
int err;
int fd;
opts_ro.open_flags = BPF_F_RDONLY;
while (true) {
switch (type) {
case BPF_OBJ_PROG:
err = bpf_prog_get_next_id(id, &id);
break;
case BPF_OBJ_MAP:
err = bpf_map_get_next_id(id, &id);
break;
default:
err = -1;
p_err("unexpected object type: %u", type);
goto err_free;
}
if (err) {
if (errno == ENOENT) {
err = 0;
break;
}
p_err("can't get next %s: %s%s", names[type],
strerror(errno),
errno == EINVAL ? " -- kernel too old?" : "");
goto err_free;
}
switch (type) {
case BPF_OBJ_PROG:
fd = bpf_prog_get_fd_by_id(id);
break;
case BPF_OBJ_MAP:
fd = bpf_map_get_fd_by_id_opts(id, &opts_ro);
break;
default:
err = -1;
p_err("unexpected object type: %u", type);
goto err_free;
}
if (fd < 0) {
if (errno == ENOENT)
continue;
p_err("can't get %s by id (%u): %s", names[type], id,
strerror(errno));
err = -1;
goto err_free;
}
memset(info, 0, *len);
if (type == BPF_OBJ_PROG)
err = bpf_prog_get_info_by_fd(fd, info, len);
else
err = bpf_map_get_info_by_fd(fd, info, len);
close(fd);
if (err) {
p_err("can't get %s info: %s", names[type],
strerror(errno));
goto err_free;
}
switch (type) {
case BPF_OBJ_PROG:
btf_id = ((struct bpf_prog_info *)info)->btf_id;
break;
case BPF_OBJ_MAP:
btf_id = ((struct bpf_map_info *)info)->btf_id;
break;
default:
err = -1;
p_err("unexpected object type: %u", type);
goto err_free;
}
if (!btf_id)
continue;
err = hashmap__append(tab, btf_id, id);
if (err) {
p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s",
btf_id, id, strerror(-err));
goto err_free;
}
}
return 0;
err_free:
hashmap__free(tab);
return err;
}
static int
build_btf_tables(struct hashmap *btf_prog_table,
struct hashmap *btf_map_table)
{
struct bpf_prog_info prog_info;
__u32 prog_len = sizeof(prog_info);
struct bpf_map_info map_info;
__u32 map_len = sizeof(map_info);
int err = 0;
err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
&prog_len);
if (err)
return err;
err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
&map_len);
if (err) {
hashmap__free(btf_prog_table);
return err;
}
return 0;
}
static void
show_btf_plain(struct bpf_btf_info *info, int fd,
struct hashmap *btf_prog_table,
struct hashmap *btf_map_table)
{
struct hashmap_entry *entry;
const char *name = u64_to_ptr(info->name);
int n;
printf("%u: ", info->id);
if (info->kernel_btf)
printf("name [%s] ", name);
else if (name && name[0])
printf("name %s ", name);
else
printf("name <anon> ");
printf("size %uB", info->btf_size);
n = 0;
hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
printf("%s%lu", n++ == 0 ? " prog_ids " : ",", (unsigned long)entry->value);
}
n = 0;
hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
printf("%s%lu", n++ == 0 ? " map_ids " : ",", (unsigned long)entry->value);
}
emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
printf("\n");
}
static void
show_btf_json(struct bpf_btf_info *info, int fd,
struct hashmap *btf_prog_table,
struct hashmap *btf_map_table)
{
struct hashmap_entry *entry;
const char *name = u64_to_ptr(info->name);
jsonw_start_object(json_wtr);
jsonw_uint_field(json_wtr, "id", info->id);
jsonw_uint_field(json_wtr, "size", info->btf_size);
jsonw_name(json_wtr, "prog_ids");
jsonw_start_array(json_wtr);
hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
jsonw_uint(json_wtr, entry->value);
}
jsonw_end_array(json_wtr);
jsonw_name(json_wtr, "map_ids");
jsonw_start_array(json_wtr);
hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
jsonw_uint(json_wtr, entry->value);
}
jsonw_end_array(json_wtr);
emit_obj_refs_json(refs_table, info->id, json_wtr);
jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
if (name && name[0])
jsonw_string_field(json_wtr, "name", name);
jsonw_end_object(json_wtr);
}
static int
show_btf(int fd, struct hashmap *btf_prog_table,
struct hashmap *btf_map_table)
{
struct bpf_btf_info info;
__u32 len = sizeof(info);
char name[64];
int err;
memset(&info, 0, sizeof(info));
err = bpf_btf_get_info_by_fd(fd, &info, &len);
if (err) {
p_err("can't get BTF object info: %s", strerror(errno));
return -1;
}
if (info.name_len) {
memset(&info, 0, sizeof(info));
info.name_len = sizeof(name);
info.name = ptr_to_u64(name);
len = sizeof(info);
err = bpf_btf_get_info_by_fd(fd, &info, &len);
if (err) {
p_err("can't get BTF object info: %s", strerror(errno));
return -1;
}
}
if (json_output)
show_btf_json(&info, fd, btf_prog_table, btf_map_table);
else
show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
return 0;
}
static int do_show(int argc, char **argv)
{
struct hashmap *btf_prog_table;
struct hashmap *btf_map_table;
int err, fd = -1;
__u32 id = 0;
if (argc == 2) {
fd = btf_parse_fd(&argc, &argv);
if (fd < 0)
return -1;
}
if (argc) {
if (fd >= 0)
close(fd);
return BAD_ARG();
}
btf_prog_table = hashmap__new(hash_fn_for_key_as_id,
equal_fn_for_key_as_id, NULL);
btf_map_table = hashmap__new(hash_fn_for_key_as_id,
equal_fn_for_key_as_id, NULL);
if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) {
hashmap__free(btf_prog_table);
hashmap__free(btf_map_table);
if (fd >= 0)
close(fd);
p_err("failed to create hashmap for object references");
return -1;
}
err = build_btf_tables(btf_prog_table, btf_map_table);
if (err) {
if (fd >= 0)
close(fd);
return err;
}
build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
if (fd >= 0) {
err = show_btf(fd, btf_prog_table, btf_map_table);
close(fd);
goto exit_free;
}
if (json_output)
jsonw_start_array(json_wtr);
while (true) {
err = bpf_btf_get_next_id(id, &id);
if (err) {
if (errno == ENOENT) {
err = 0;
break;
}
p_err("can't get next BTF object: %s%s",
strerror(errno),
errno == EINVAL ? " -- kernel too old?" : "");
err = -1;
break;
}
fd = bpf_btf_get_fd_by_id(id);
if (fd < 0) {
if (errno == ENOENT)
continue;
p_err("can't get BTF object by id (%u): %s",
id, strerror(errno));
err = -1;
break;
}
err = show_btf(fd, btf_prog_table, btf_map_table);
close(fd);
if (err)
break;
}
if (json_output)
jsonw_end_array(json_wtr);
exit_free:
hashmap__free(btf_prog_table);
hashmap__free(btf_map_table);
delete_obj_refs_table(refs_table);
return err;
}
static int do_help(int argc, char **argv)
{
if (json_output) {
jsonw_null(json_wtr);
return 0;
}
fprintf(stderr,
"Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
" %1$s %2$s dump BTF_SRC [format FORMAT] [root_id ROOT_ID]\n"
" %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"
" " HELP_SPEC_MAP "\n"
" " HELP_SPEC_PROGRAM "\n"
" " HELP_SPEC_OPTIONS " |\n"
" {-B|--base-btf} }\n"
"",
bin_name, "btf");
return 0;
}
static const struct cmd cmds[] = {
{ "show", do_show },
{ "list", do_show },
{ "help", do_help },
{ "dump", do_dump },
{ 0 }
};
int do_btf(int argc, char **argv)
{
return cmd_select(cmds, argc, argv, do_help);
}
