blob: 7e4c5586bd877508c1da3c47c17026c03b4af873 [file] [log] [blame]
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */
#include <byteswap.h>
#include <endian.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/utsname.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/btf.h>
#include <gelf.h>
#include "btf.h"
#include "bpf.h"
#include "libbpf.h"
#include "libbpf_internal.h"
#include "hashmap.h"
#include "strset.h"
#define BTF_MAX_NR_TYPES 0x7fffffffU
#define BTF_MAX_STR_OFFSET 0x7fffffffU
static struct btf_type btf_void;
struct btf {
/* raw BTF data in native endianness */
void *raw_data;
/* raw BTF data in non-native endianness */
void *raw_data_swapped;
__u32 raw_size;
/* whether target endianness differs from the native one */
bool swapped_endian;
/*
* When BTF is loaded from an ELF or raw memory it is stored
* in a contiguous memory block. The hdr, type_data, and, strs_data
* point inside that memory region to their respective parts of BTF
* representation:
*
* +--------------------------------+
* | Header | Types | Strings |
* +--------------------------------+
* ^ ^ ^
* | | |
* hdr | |
* types_data-+ |
* strs_data------------+
*
* If BTF data is later modified, e.g., due to types added or
* removed, BTF deduplication performed, etc, this contiguous
* representation is broken up into three independently allocated
* memory regions to be able to modify them independently.
* raw_data is nulled out at that point, but can be later allocated
* and cached again if user calls btf__raw_data(), at which point
* raw_data will contain a contiguous copy of header, types, and
* strings:
*
* +----------+ +---------+ +-----------+
* | Header | | Types | | Strings |
* +----------+ +---------+ +-----------+
* ^ ^ ^
* | | |
* hdr | |
* types_data----+ |
* strset__data(strs_set)-----+
*
* +----------+---------+-----------+
* | Header | Types | Strings |
* raw_data----->+----------+---------+-----------+
*/
struct btf_header *hdr;
void *types_data;
size_t types_data_cap; /* used size stored in hdr->type_len */
/* type ID to `struct btf_type *` lookup index
* type_offs[0] corresponds to the first non-VOID type:
* - for base BTF it's type [1];
* - for split BTF it's the first non-base BTF type.
*/
__u32 *type_offs;
size_t type_offs_cap;
/* number of types in this BTF instance:
* - doesn't include special [0] void type;
* - for split BTF counts number of types added on top of base BTF.
*/
__u32 nr_types;
/* if not NULL, points to the base BTF on top of which the current
* split BTF is based
*/
struct btf *base_btf;
/* BTF type ID of the first type in this BTF instance:
* - for base BTF it's equal to 1;
* - for split BTF it's equal to biggest type ID of base BTF plus 1.
*/
int start_id;
/* logical string offset of this BTF instance:
* - for base BTF it's equal to 0;
* - for split BTF it's equal to total size of base BTF's string section size.
*/
int start_str_off;
/* only one of strs_data or strs_set can be non-NULL, depending on
* whether BTF is in a modifiable state (strs_set is used) or not
* (strs_data points inside raw_data)
*/
void *strs_data;
/* a set of unique strings */
struct strset *strs_set;
/* whether strings are already deduplicated */
bool strs_deduped;
/* BTF object FD, if loaded into kernel */
int fd;
/* Pointer size (in bytes) for a target architecture of this BTF */
int ptr_sz;
};
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
/* Ensure given dynamically allocated memory region pointed to by *data* with
* capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough
* memory to accomodate *add_cnt* new elements, assuming *cur_cnt* elements
* are already used. At most *max_cnt* elements can be ever allocated.
* If necessary, memory is reallocated and all existing data is copied over,
* new pointer to the memory region is stored at *data, new memory region
* capacity (in number of elements) is stored in *cap.
* On success, memory pointer to the beginning of unused memory is returned.
* On error, NULL is returned.
*/
void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
size_t cur_cnt, size_t max_cnt, size_t add_cnt)
{
size_t new_cnt;
void *new_data;
if (cur_cnt + add_cnt <= *cap_cnt)
return *data + cur_cnt * elem_sz;
/* requested more than the set limit */
if (cur_cnt + add_cnt > max_cnt)
return NULL;
new_cnt = *cap_cnt;
new_cnt += new_cnt / 4; /* expand by 25% */
if (new_cnt < 16) /* but at least 16 elements */
new_cnt = 16;
if (new_cnt > max_cnt) /* but not exceeding a set limit */
new_cnt = max_cnt;
if (new_cnt < cur_cnt + add_cnt) /* also ensure we have enough memory */
new_cnt = cur_cnt + add_cnt;
new_data = libbpf_reallocarray(*data, new_cnt, elem_sz);
if (!new_data)
return NULL;
/* zero out newly allocated portion of memory */
memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz);
*data = new_data;
*cap_cnt = new_cnt;
return new_data + cur_cnt * elem_sz;
}
/* Ensure given dynamically allocated memory region has enough allocated space
* to accommodate *need_cnt* elements of size *elem_sz* bytes each
*/
int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt)
{
void *p;
if (need_cnt <= *cap_cnt)
return 0;
p = libbpf_add_mem(data, cap_cnt, elem_sz, *cap_cnt, SIZE_MAX, need_cnt - *cap_cnt);
if (!p)
return -ENOMEM;
return 0;
}
static void *btf_add_type_offs_mem(struct btf *btf, size_t add_cnt)
{
return libbpf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32),
btf->nr_types, BTF_MAX_NR_TYPES, add_cnt);
}
static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off)
{
__u32 *p;
p = btf_add_type_offs_mem(btf, 1);
if (!p)
return -ENOMEM;
*p = type_off;
return 0;
}
static void btf_bswap_hdr(struct btf_header *h)
{
h->magic = bswap_16(h->magic);
h->hdr_len = bswap_32(h->hdr_len);
h->type_off = bswap_32(h->type_off);
h->type_len = bswap_32(h->type_len);
h->str_off = bswap_32(h->str_off);
h->str_len = bswap_32(h->str_len);
}
static int btf_parse_hdr(struct btf *btf)
{
struct btf_header *hdr = btf->hdr;
__u32 meta_left;
if (btf->raw_size < sizeof(struct btf_header)) {
pr_debug("BTF header not found\n");
return -EINVAL;
}
if (hdr->magic == bswap_16(BTF_MAGIC)) {
btf->swapped_endian = true;
if (bswap_32(hdr->hdr_len) != sizeof(struct btf_header)) {
pr_warn("Can't load BTF with non-native endianness due to unsupported header length %u\n",
bswap_32(hdr->hdr_len));
return -ENOTSUP;
}
btf_bswap_hdr(hdr);
} else if (hdr->magic != BTF_MAGIC) {
pr_debug("Invalid BTF magic: %x\n", hdr->magic);
return -EINVAL;
}
if (btf->raw_size < hdr->hdr_len) {
pr_debug("BTF header len %u larger than data size %u\n",
hdr->hdr_len, btf->raw_size);
return -EINVAL;
}
meta_left = btf->raw_size - hdr->hdr_len;
if (meta_left < (long long)hdr->str_off + hdr->str_len) {
pr_debug("Invalid BTF total size: %u\n", btf->raw_size);
return -EINVAL;
}
if ((long long)hdr->type_off + hdr->type_len > hdr->str_off) {
pr_debug("Invalid BTF data sections layout: type data at %u + %u, strings data at %u + %u\n",
hdr->type_off, hdr->type_len, hdr->str_off, hdr->str_len);
return -EINVAL;
}
if (hdr->type_off % 4) {
pr_debug("BTF type section is not aligned to 4 bytes\n");
return -EINVAL;
}
return 0;
}
static int btf_parse_str_sec(struct btf *btf)
{
const struct btf_header *hdr = btf->hdr;
const char *start = btf->strs_data;
const char *end = start + btf->hdr->str_len;
if (btf->base_btf && hdr->str_len == 0)
return 0;
if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET || end[-1]) {
pr_debug("Invalid BTF string section\n");
return -EINVAL;
}
if (!btf->base_btf && start[0]) {
pr_debug("Invalid BTF string section\n");
return -EINVAL;
}
return 0;
}
static int btf_type_size(const struct btf_type *t)
{
const int base_size = sizeof(struct btf_type);
__u16 vlen = btf_vlen(t);
switch (btf_kind(t)) {
case BTF_KIND_FWD:
case BTF_KIND_CONST:
case BTF_KIND_VOLATILE:
case BTF_KIND_RESTRICT:
case BTF_KIND_PTR:
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_FLOAT:
return base_size;
case BTF_KIND_INT:
return base_size + sizeof(__u32);
case BTF_KIND_ENUM:
return base_size + vlen * sizeof(struct btf_enum);
case BTF_KIND_ARRAY:
return base_size + sizeof(struct btf_array);
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
return base_size + vlen * sizeof(struct btf_member);
case BTF_KIND_FUNC_PROTO:
return base_size + vlen * sizeof(struct btf_param);
case BTF_KIND_VAR:
return base_size + sizeof(struct btf_var);
case BTF_KIND_DATASEC:
return base_size + vlen * sizeof(struct btf_var_secinfo);
case BTF_KIND_DECL_TAG:
return base_size + sizeof(struct btf_decl_tag);
default:
pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
return -EINVAL;
}
}
static void btf_bswap_type_base(struct btf_type *t)
{
t->name_off = bswap_32(t->name_off);
t->info = bswap_32(t->info);
t->type = bswap_32(t->type);
}
static int btf_bswap_type_rest(struct btf_type *t)
{
struct btf_var_secinfo *v;
struct btf_member *m;
struct btf_array *a;
struct btf_param *p;
struct btf_enum *e;
__u16 vlen = btf_vlen(t);
int i;
switch (btf_kind(t)) {
case BTF_KIND_FWD:
case BTF_KIND_CONST:
case BTF_KIND_VOLATILE:
case BTF_KIND_RESTRICT:
case BTF_KIND_PTR:
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_FLOAT:
return 0;
case BTF_KIND_INT:
*(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1));
return 0;
case BTF_KIND_ENUM:
for (i = 0, e = btf_enum(t); i < vlen; i++, e++) {
e->name_off = bswap_32(e->name_off);
e->val = bswap_32(e->val);
}
return 0;
case BTF_KIND_ARRAY:
a = btf_array(t);
a->type = bswap_32(a->type);
a->index_type = bswap_32(a->index_type);
a->nelems = bswap_32(a->nelems);
return 0;
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
for (i = 0, m = btf_members(t); i < vlen; i++, m++) {
m->name_off = bswap_32(m->name_off);
m->type = bswap_32(m->type);
m->offset = bswap_32(m->offset);
}
return 0;
case BTF_KIND_FUNC_PROTO:
for (i = 0, p = btf_params(t); i < vlen; i++, p++) {
p->name_off = bswap_32(p->name_off);
p->type = bswap_32(p->type);
}
return 0;
case BTF_KIND_VAR:
btf_var(t)->linkage = bswap_32(btf_var(t)->linkage);
return 0;
case BTF_KIND_DATASEC:
for (i = 0, v = btf_var_secinfos(t); i < vlen; i++, v++) {
v->type = bswap_32(v->type);
v->offset = bswap_32(v->offset);
v->size = bswap_32(v->size);
}
return 0;
case BTF_KIND_DECL_TAG:
btf_decl_tag(t)->component_idx = bswap_32(btf_decl_tag(t)->component_idx);
return 0;
default:
pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
return -EINVAL;
}
}
static int btf_parse_type_sec(struct btf *btf)
{
struct btf_header *hdr = btf->hdr;
void *next_type = btf->types_data;
void *end_type = next_type + hdr->type_len;
int err, type_size;
while (next_type + sizeof(struct btf_type) <= end_type) {
if (btf->swapped_endian)
btf_bswap_type_base(next_type);
type_size = btf_type_size(next_type);
if (type_size < 0)
return type_size;
if (next_type + type_size > end_type) {
pr_warn("BTF type [%d] is malformed\n", btf->start_id + btf->nr_types);
return -EINVAL;
}
if (btf->swapped_endian && btf_bswap_type_rest(next_type))
return -EINVAL;
err = btf_add_type_idx_entry(btf, next_type - btf->types_data);
if (err)
return err;
next_type += type_size;
btf->nr_types++;
}
if (next_type != end_type) {
pr_warn("BTF types data is malformed\n");
return -EINVAL;
}
return 0;
}
__u32 btf__get_nr_types(const struct btf *btf)
{
return btf->start_id + btf->nr_types - 1;
}
__u32 btf__type_cnt(const struct btf *btf)
{
return btf->start_id + btf->nr_types;
}
const struct btf *btf__base_btf(const struct btf *btf)
{
return btf->base_btf;
}
/* internal helper returning non-const pointer to a type */
struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id)
{
if (type_id == 0)
return &btf_void;
if (type_id < btf->start_id)
return btf_type_by_id(btf->base_btf, type_id);
return btf->types_data + btf->type_offs[type_id - btf->start_id];
}
const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
{
if (type_id >= btf->start_id + btf->nr_types)
return errno = EINVAL, NULL;
return btf_type_by_id((struct btf *)btf, type_id);
}
static int determine_ptr_size(const struct btf *btf)
{
const struct btf_type *t;
const char *name;
int i, n;
if (btf->base_btf && btf->base_btf->ptr_sz > 0)
return btf->base_btf->ptr_sz;
n = btf__type_cnt(btf);
for (i = 1; i < n; i++) {
t = btf__type_by_id(btf, i);
if (!btf_is_int(t))
continue;
name = btf__name_by_offset(btf, t->name_off);
if (!name)
continue;
if (strcmp(name, "long int") == 0 ||
strcmp(name, "long unsigned int") == 0) {
if (t->size != 4 && t->size != 8)
continue;
return t->size;
}
}
return -1;
}
static size_t btf_ptr_sz(const struct btf *btf)
{
if (!btf->ptr_sz)
((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
return btf->ptr_sz < 0 ? sizeof(void *) : btf->ptr_sz;
}
/* Return pointer size this BTF instance assumes. The size is heuristically
* determined by looking for 'long' or 'unsigned long' integer type and
* recording its size in bytes. If BTF type information doesn't have any such
* type, this function returns 0. In the latter case, native architecture's
* pointer size is assumed, so will be either 4 or 8, depending on
* architecture that libbpf was compiled for. It's possible to override
* guessed value by using btf__set_pointer_size() API.
*/
size_t btf__pointer_size(const struct btf *btf)
{
if (!btf->ptr_sz)
((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
if (btf->ptr_sz < 0)
/* not enough BTF type info to guess */
return 0;
return btf->ptr_sz;
}
/* Override or set pointer size in bytes. Only values of 4 and 8 are
* supported.
*/
int btf__set_pointer_size(struct btf *btf, size_t ptr_sz)
{
if (ptr_sz != 4 && ptr_sz != 8)
return libbpf_err(-EINVAL);
btf->ptr_sz = ptr_sz;
return 0;
}
static bool is_host_big_endian(void)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
return false;
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
return true;
#else
# error "Unrecognized __BYTE_ORDER__"
#endif
}
enum btf_endianness btf__endianness(const struct btf *btf)
{
if (is_host_big_endian())
return btf->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN;
else
return btf->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN;
}
int btf__set_endianness(struct btf *btf, enum btf_endianness endian)
{
if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN)
return libbpf_err(-EINVAL);
btf->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN);
if (!btf->swapped_endian) {
free(btf->raw_data_swapped);
btf->raw_data_swapped = NULL;
}
return 0;
}
static bool btf_type_is_void(const struct btf_type *t)
{
return t == &btf_void || btf_is_fwd(t);
}
static bool btf_type_is_void_or_null(const struct btf_type *t)
{
return !t || btf_type_is_void(t);
}
#define MAX_RESOLVE_DEPTH 32
__s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
{
const struct btf_array *array;
const struct btf_type *t;
__u32 nelems = 1;
__s64 size = -1;
int i;
t = btf__type_by_id(btf, type_id);
for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t); i++) {
switch (btf_kind(t)) {
case BTF_KIND_INT:
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
case BTF_KIND_ENUM:
case BTF_KIND_DATASEC:
case BTF_KIND_FLOAT:
size = t->size;
goto done;
case BTF_KIND_PTR:
size = btf_ptr_sz(btf);
goto done;
case BTF_KIND_TYPEDEF:
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
case BTF_KIND_VAR:
case BTF_KIND_DECL_TAG:
type_id = t->type;
break;
case BTF_KIND_ARRAY:
array = btf_array(t);
if (nelems && array->nelems > UINT32_MAX / nelems)
return libbpf_err(-E2BIG);
nelems *= array->nelems;
type_id = array->type;
break;
default:
return libbpf_err(-EINVAL);
}
t = btf__type_by_id(btf, type_id);
}
done:
if (size < 0)
return libbpf_err(-EINVAL);
if (nelems && size > UINT32_MAX / nelems)
return libbpf_err(-E2BIG);
return nelems * size;
}
int btf__align_of(const struct btf *btf, __u32 id)
{
const struct btf_type *t = btf__type_by_id(btf, id);
__u16 kind = btf_kind(t);
switch (kind) {
case BTF_KIND_INT:
case BTF_KIND_ENUM:
case BTF_KIND_FLOAT:
return min(btf_ptr_sz(btf), (size_t)t->size);
case BTF_KIND_PTR:
return btf_ptr_sz(btf);
case BTF_KIND_TYPEDEF:
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
return btf__align_of(btf, t->type);
case BTF_KIND_ARRAY:
return btf__align_of(btf, btf_array(t)->type);
case BTF_KIND_STRUCT:
case BTF_KIND_UNION: {
const struct btf_member *m = btf_members(t);
__u16 vlen = btf_vlen(t);
int i, max_align = 1, align;
for (i = 0; i < vlen; i++, m++) {
align = btf__align_of(btf, m->type);
if (align <= 0)
return libbpf_err(align);
max_align = max(max_align, align);
}
return max_align;
}
default:
pr_warn("unsupported BTF_KIND:%u\n", btf_kind(t));
return errno = EINVAL, 0;
}
}
int btf__resolve_type(const struct btf *btf, __u32 type_id)
{
const struct btf_type *t;
int depth = 0;
t = btf__type_by_id(btf, type_id);
while (depth < MAX_RESOLVE_DEPTH &&
!btf_type_is_void_or_null(t) &&
(btf_is_mod(t) || btf_is_typedef(t) || btf_is_var(t))) {
type_id = t->type;
t = btf__type_by_id(btf, type_id);
depth++;
}
if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
return libbpf_err(-EINVAL);
return type_id;
}
__s32 btf__find_by_name(const struct btf *btf, const char *type_name)
{
__u32 i, nr_types = btf__type_cnt(btf);
if (!strcmp(type_name, "void"))
return 0;
for (i = 1; i < nr_types; i++) {
const struct btf_type *t = btf__type_by_id(btf, i);
const char *name = btf__name_by_offset(btf, t->name_off);
if (name && !strcmp(type_name, name))
return i;
}
return libbpf_err(-ENOENT);
}
static __s32 btf_find_by_name_kind(const struct btf *btf, int start_id,
const char *type_name, __u32 kind)
{
__u32 i, nr_types = btf__type_cnt(btf);
if (kind == BTF_KIND_UNKN || !strcmp(type_name, "void"))
return 0;
for (i = start_id; i < nr_types; i++) {
const struct btf_type *t = btf__type_by_id(btf, i);
const char *name;
if (btf_kind(t) != kind)
continue;
name = btf__name_by_offset(btf, t->name_off);
if (name && !strcmp(type_name, name))
return i;
}
return libbpf_err(-ENOENT);
}
__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
__u32 kind)
{
return btf_find_by_name_kind(btf, btf->start_id, type_name, kind);
}
__s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
__u32 kind)
{
return btf_find_by_name_kind(btf, 1, type_name, kind);
}
static bool btf_is_modifiable(const struct btf *btf)
{
return (void *)btf->hdr != btf->raw_data;
}
void btf__free(struct btf *btf)
{
if (IS_ERR_OR_NULL(btf))
return;
if (btf->fd >= 0)
close(btf->fd);
if (btf_is_modifiable(btf)) {
/* if BTF was modified after loading, it will have a split
* in-memory representation for header, types, and strings
* sections, so we need to free all of them individually. It
* might still have a cached contiguous raw data present,
* which will be unconditionally freed below.
*/
free(btf->hdr);
free(btf->types_data);
strset__free(btf->strs_set);
}
free(btf->raw_data);
free(btf->raw_data_swapped);
free(btf->type_offs);
free(btf);
}
static struct btf *btf_new_empty(struct btf *base_btf)
{
struct btf *btf;
btf = calloc(1, sizeof(*btf));
if (!btf)
return ERR_PTR(-ENOMEM);
btf->nr_types = 0;
btf->start_id = 1;
btf->start_str_off = 0;
btf->fd = -1;
btf->ptr_sz = sizeof(void *);
btf->swapped_endian = false;
if (base_btf) {
btf->base_btf = base_btf;
btf->start_id = btf__type_cnt(base_btf);
btf->start_str_off = base_btf->hdr->str_len;
}
/* +1 for empty string at offset 0 */
btf->raw_size = sizeof(struct btf_header) + (base_btf ? 0 : 1);
btf->raw_data = calloc(1, btf->raw_size);
if (!btf->raw_data) {
free(btf);
return ERR_PTR(-ENOMEM);
}
btf->hdr = btf->raw_data;
btf->hdr->hdr_len = sizeof(struct btf_header);
btf->hdr->magic = BTF_MAGIC;
btf->hdr->version = BTF_VERSION;
btf->types_data = btf->raw_data + btf->hdr->hdr_len;
btf->strs_data = btf->raw_data + btf->hdr->hdr_len;
btf->hdr->str_len = base_btf ? 0 : 1; /* empty string at offset 0 */
return btf;
}
struct btf *btf__new_empty(void)
{
return libbpf_ptr(btf_new_empty(NULL));
}
struct btf *btf__new_empty_split(struct btf *base_btf)
{
return libbpf_ptr(btf_new_empty(base_btf));
}
static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf)
{
struct btf *btf;
int err;
btf = calloc(1, sizeof(struct btf));
if (!btf)
return ERR_PTR(-ENOMEM);
btf->nr_types = 0;
btf->start_id = 1;
btf->start_str_off = 0;
btf->fd = -1;
if (base_btf) {
btf->base_btf = base_btf;
btf->start_id = btf__type_cnt(base_btf);
btf->start_str_off = base_btf->hdr->str_len;
}
btf->raw_data = malloc(size);
if (!btf->raw_data) {
err = -ENOMEM;
goto done;
}
memcpy(btf->raw_data, data, size);
btf->raw_size = size;
btf->hdr = btf->raw_data;
err = btf_parse_hdr(btf);
if (err)
goto done;
btf->strs_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->str_off;
btf->types_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->type_off;
err = btf_parse_str_sec(btf);
err = err ?: btf_parse_type_sec(btf);
if (err)
goto done;
done:
if (err) {
btf__free(btf);
return ERR_PTR(err);
}
return btf;
}
struct btf *btf__new(const void *data, __u32 size)
{
return libbpf_ptr(btf_new(data, size, NULL));
}
static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
struct btf_ext **btf_ext)
{
Elf_Data *btf_data = NULL, *btf_ext_data = NULL;
int err = 0, fd = -1, idx = 0;
struct btf *btf = NULL;
Elf_Scn *scn = NULL;
Elf *elf = NULL;
GElf_Ehdr ehdr;
size_t shstrndx;
if (elf_version(EV_CURRENT) == EV_NONE) {
pr_warn("failed to init libelf for %s\n", path);
return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
}
fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
err = -errno;
pr_warn("failed to open %s: %s\n", path, strerror(errno));
return ERR_PTR(err);
}
err = -LIBBPF_ERRNO__FORMAT;
elf = elf_begin(fd, ELF_C_READ, NULL);
if (!elf) {
pr_warn("failed to open %s as ELF file\n", path);
goto done;
}
if (!gelf_getehdr(elf, &ehdr)) {
pr_warn("failed to get EHDR from %s\n", path);
goto done;
}
if (elf_getshdrstrndx(elf, &shstrndx)) {
pr_warn("failed to get section names section index for %s\n",
path);
goto done;
}
if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) {
pr_warn("failed to get e_shstrndx from %s\n", path);
goto done;
}
while ((scn = elf_nextscn(elf, scn)) != NULL) {
GElf_Shdr sh;
char *name;
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warn("failed to get section(%d) header from %s\n",
idx, path);
goto done;
}
name = elf_strptr(elf, shstrndx, sh.sh_name);
if (!name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, path);
goto done;
}
if (strcmp(name, BTF_ELF_SEC) == 0) {
btf_data = elf_getdata(scn, 0);
if (!btf_data) {
pr_warn("failed to get section(%d, %s) data from %s\n",
idx, name, path);
goto done;
}
continue;
} else if (btf_ext && strcmp(name, BTF_EXT_ELF_SEC) == 0) {
btf_ext_data = elf_getdata(scn, 0);
if (!btf_ext_data) {
pr_warn("failed to get section(%d, %s) data from %s\n",
idx, name, path);
goto done;
}
continue;
}
}
err = 0;
if (!btf_data) {
err = -ENOENT;
goto done;
}
btf = btf_new(btf_data->d_buf, btf_data->d_size, base_btf);
err = libbpf_get_error(btf);
if (err)
goto done;
switch (gelf_getclass(elf)) {
case ELFCLASS32:
btf__set_pointer_size(btf, 4);
break;
case ELFCLASS64:
btf__set_pointer_size(btf, 8);
break;
default:
pr_warn("failed to get ELF class (bitness) for %s\n", path);
break;
}
if (btf_ext && btf_ext_data) {
*btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size);
err = libbpf_get_error(*btf_ext);
if (err)
goto done;
} else if (btf_ext) {
*btf_ext = NULL;
}
done:
if (elf)
elf_end(elf);
close(fd);
if (!err)
return btf;
if (btf_ext)
btf_ext__free(*btf_ext);
btf__free(btf);
return ERR_PTR(err);
}
struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext)
{
return libbpf_ptr(btf_parse_elf(path, NULL, btf_ext));
}
struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf)
{
return libbpf_ptr(btf_parse_elf(path, base_btf, NULL));
}
static struct btf *btf_parse_raw(const char *path, struct btf *base_btf)
{
struct btf *btf = NULL;
void *data = NULL;
FILE *f = NULL;
__u16 magic;
int err = 0;
long sz;
f = fopen(path, "rb");
if (!f) {
err = -errno;
goto err_out;
}
/* check BTF magic */
if (fread(&magic, 1, sizeof(magic), f) < sizeof(magic)) {
err = -EIO;
goto err_out;
}
if (magic != BTF_MAGIC && magic != bswap_16(BTF_MAGIC)) {
/* definitely not a raw BTF */
err = -EPROTO;
goto err_out;
}
/* get file size */
if (fseek(f, 0, SEEK_END)) {
err = -errno;
goto err_out;
}
sz = ftell(f);
if (sz < 0) {
err = -errno;
goto err_out;
}
/* rewind to the start */
if (fseek(f, 0, SEEK_SET)) {
err = -errno;
goto err_out;
}
/* pre-alloc memory and read all of BTF data */
data = malloc(sz);
if (!data) {
err = -ENOMEM;
goto err_out;
}
if (fread(data, 1, sz, f) < sz) {
err = -EIO;
goto err_out;
}
/* finally parse BTF data */
btf = btf_new(data, sz, base_btf);
err_out:
free(data);
if (f)
fclose(f);
return err ? ERR_PTR(err) : btf;
}
struct btf *btf__parse_raw(const char *path)
{
return libbpf_ptr(btf_parse_raw(path, NULL));
}
struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf)
{
return libbpf_ptr(btf_parse_raw(path, base_btf));
}
static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext)
{
struct btf *btf;
int err;
if (btf_ext)
*btf_ext = NULL;
btf = btf_parse_raw(path, base_btf);
err = libbpf_get_error(btf);
if (!err)
return btf;
if (err != -EPROTO)
return ERR_PTR(err);
return btf_parse_elf(path, base_btf, btf_ext);
}
struct btf *btf__parse(const char *path, struct btf_ext **btf_ext)
{
return libbpf_ptr(btf_parse(path, NULL, btf_ext));
}
struct btf *btf__parse_split(const char *path, struct btf *base_btf)
{
return libbpf_ptr(btf_parse(path, base_btf, NULL));
}
static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian);
int btf__load_into_kernel(struct btf *btf)
{
__u32 log_buf_size = 0, raw_size;
char *log_buf = NULL;
void *raw_data;
int err = 0;
if (btf->fd >= 0)
return libbpf_err(-EEXIST);
retry_load:
if (log_buf_size) {
log_buf = malloc(log_buf_size);
if (!log_buf)
return libbpf_err(-ENOMEM);
*log_buf = 0;
}
raw_data = btf_get_raw_data(btf, &raw_size, false);
if (!raw_data) {
err = -ENOMEM;
goto done;
}
/* cache native raw data representation */
btf->raw_size = raw_size;
btf->raw_data = raw_data;
btf->fd = bpf_load_btf(raw_data, raw_size, log_buf, log_buf_size, false);
if (btf->fd < 0) {
if (!log_buf || errno == ENOSPC) {
log_buf_size = max((__u32)BPF_LOG_BUF_SIZE,
log_buf_size << 1);
free(log_buf);
goto retry_load;
}
err = -errno;
pr_warn("Error loading BTF: %s(%d)\n", strerror(errno), errno);
if (*log_buf)
pr_warn("%s\n", log_buf);
goto done;
}
done:
free(log_buf);
return libbpf_err(err);
}
int btf__load(struct btf *) __attribute__((alias("btf__load_into_kernel")));
int btf__fd(const struct btf *btf)
{
return btf->fd;
}
void btf__set_fd(struct btf *btf, int fd)
{
btf->fd = fd;
}
static const void *btf_strs_data(const struct btf *btf)
{
return btf->strs_data ? btf->strs_data : strset__data(btf->strs_set);
}
static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian)
{
struct btf_header *hdr = btf->hdr;
struct btf_type *t;
void *data, *p;
__u32 data_sz;
int i;
data = swap_endian ? btf->raw_data_swapped : btf->raw_data;
if (data) {
*size = btf->raw_size;
return data;
}
data_sz = hdr->hdr_len + hdr->type_len + hdr->str_len;
data = calloc(1, data_sz);
if (!data)
return NULL;
p = data;
memcpy(p, hdr, hdr->hdr_len);
if (swap_endian)
btf_bswap_hdr(p);
p += hdr->hdr_len;
memcpy(p, btf->types_data, hdr->type_len);
if (swap_endian) {
for (i = 0; i < btf->nr_types; i++) {
t = p + btf->type_offs[i];
/* btf_bswap_type_rest() relies on native t->info, so
* we swap base type info after we swapped all the
* additional information
*/
if (btf_bswap_type_rest(t))
goto err_out;
btf_bswap_type_base(t);
}
}
p += hdr->type_len;
memcpy(p, btf_strs_data(btf), hdr->str_len);
p += hdr->str_len;
*size = data_sz;
return data;
err_out:
free(data);
return NULL;
}
const void *btf__raw_data(const struct btf *btf_ro, __u32 *size)
{
struct btf *btf = (struct btf *)btf_ro;
__u32 data_sz;
void *data;
data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian);
if (!data)
return errno = ENOMEM, NULL;
btf->raw_size = data_sz;
if (btf->swapped_endian)
btf->raw_data_swapped = data;
else
btf->raw_data = data;
*size = data_sz;
return data;
}
__attribute__((alias("btf__raw_data")))
const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
const char *btf__str_by_offset(const struct btf *btf, __u32 offset)
{
if (offset < btf->start_str_off)
return btf__str_by_offset(btf->base_btf, offset);
else if (offset - btf->start_str_off < btf->hdr->str_len)
return btf_strs_data(btf) + (offset - btf->start_str_off);
else
return errno = EINVAL, NULL;
}
const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
{
return btf__str_by_offset(btf, offset);
}
struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf)
{
struct bpf_btf_info btf_info;
__u32 len = sizeof(btf_info);
__u32 last_size;
struct btf *btf;
void *ptr;
int err;
/* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
* let's start with a sane default - 4KiB here - and resize it only if
* bpf_obj_get_info_by_fd() needs a bigger buffer.
*/
last_size = 4096;
ptr = malloc(last_size);
if (!ptr)
return ERR_PTR(-ENOMEM);
memset(&btf_info, 0, sizeof(btf_info));
btf_info.btf = ptr_to_u64(ptr);
btf_info.btf_size = last_size;
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
if (!err && btf_info.btf_size > last_size) {
void *temp_ptr;
last_size = btf_info.btf_size;
temp_ptr = realloc(ptr, last_size);
if (!temp_ptr) {
btf = ERR_PTR(-ENOMEM);
goto exit_free;
}
ptr = temp_ptr;
len = sizeof(btf_info);
memset(&btf_info, 0, sizeof(btf_info));
btf_info.btf = ptr_to_u64(ptr);
btf_info.btf_size = last_size;
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
}
if (err || btf_info.btf_size > last_size) {
btf = err ? ERR_PTR(-errno) : ERR_PTR(-E2BIG);
goto exit_free;
}
btf = btf_new(ptr, btf_info.btf_size, base_btf);
exit_free:
free(ptr);
return btf;
}
struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf)
{
struct btf *btf;
int btf_fd;
btf_fd = bpf_btf_get_fd_by_id(id);
if (btf_fd < 0)
return libbpf_err_ptr(-errno);
btf = btf_get_from_fd(btf_fd, base_btf);
close(btf_fd);
return libbpf_ptr(btf);
}
struct btf *btf__load_from_kernel_by_id(__u32 id)
{
return btf__load_from_kernel_by_id_split(id, NULL);
}
int btf__get_from_id(__u32 id, struct btf **btf)
{
struct btf *res;
int err;
*btf = NULL;
res = btf__load_from_kernel_by_id(id);
err = libbpf_get_error(res);
if (err)
return libbpf_err(err);
*btf = res;
return 0;
}
int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
__u32 expected_key_size, __u32 expected_value_size,
__u32 *key_type_id, __u32 *value_type_id)
{
const struct btf_type *container_type;
const struct btf_member *key, *value;
const size_t max_name = 256;
char container_name[max_name];
__s64 key_size, value_size;
__s32 container_id;
if (snprintf(container_name, max_name, "____btf_map_%s", map_name) == max_name) {
pr_warn("map:%s length of '____btf_map_%s' is too long\n",
map_name, map_name);
return libbpf_err(-EINVAL);
}
container_id = btf__find_by_name(btf, container_name);
if (container_id < 0) {
pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n",
map_name, container_name);
return libbpf_err(container_id);
}
container_type = btf__type_by_id(btf, container_id);
if (!container_type) {
pr_warn("map:%s cannot find BTF type for container_id:%u\n",
map_name, container_id);
return libbpf_err(-EINVAL);
}
if (!btf_is_struct(container_type) || btf_vlen(container_type) < 2) {
pr_warn("map:%s container_name:%s is an invalid container struct\n",
map_name, container_name);
return libbpf_err(-EINVAL);
}
key = btf_members(container_type);
value = key + 1;
key_size = btf__resolve_size(btf, key->type);
if (key_size < 0) {
pr_warn("map:%s invalid BTF key_type_size\n", map_name);
return libbpf_err(key_size);
}
if (expected_key_size != key_size) {
pr_warn("map:%s btf_key_type_size:%u != map_def_key_size:%u\n",
map_name, (__u32)key_size, expected_key_size);
return libbpf_err(-EINVAL);
}
value_size = btf__resolve_size(btf, value->type);
if (value_size < 0) {
pr_warn("map:%s invalid BTF value_type_size\n", map_name);
return libbpf_err(value_size);
}
if (expected_value_size != value_size) {
pr_warn("map:%s btf_value_type_size:%u != map_def_value_size:%u\n",
map_name, (__u32)value_size, expected_value_size);
return libbpf_err(-EINVAL);
}
*key_type_id = key->type;
*value_type_id = value->type;
return 0;
}
static void btf_invalidate_raw_data(struct btf *btf)
{
if (btf->raw_data) {
free(btf->raw_data);
btf->raw_data = NULL;
}
if (btf->raw_data_swapped) {
free(btf->raw_data_swapped);
btf->raw_data_swapped = NULL;
}
}
/* Ensure BTF is ready to be modified (by splitting into a three memory
* regions for header, types, and strings). Also invalidate cached
* raw_data, if any.
*/
static int btf_ensure_modifiable(struct btf *btf)
{
void *hdr, *types;
struct strset *set = NULL;
int err = -ENOMEM;
if (btf_is_modifiable(btf)) {
/* any BTF modification invalidates raw_data */
btf_invalidate_raw_data(btf);
return 0;
}
/* split raw data into three memory regions */
hdr = malloc(btf->hdr->hdr_len);
types = malloc(btf->hdr->type_len);
if (!hdr || !types)
goto err_out;
memcpy(hdr, btf->hdr, btf->hdr->hdr_len);
memcpy(types, btf->types_data, btf->hdr->type_len);
/* build lookup index for all strings */
set = strset__new(BTF_MAX_STR_OFFSET, btf->strs_data, btf->hdr->str_len);
if (IS_ERR(set)) {
err = PTR_ERR(set);
goto err_out;
}
/* only when everything was successful, update internal state */
btf->hdr = hdr;
btf->types_data = types;
btf->types_data_cap = btf->hdr->type_len;
btf->strs_data = NULL;
btf->strs_set = set;
/* if BTF was created from scratch, all strings are guaranteed to be
* unique and deduplicated
*/
if (btf->hdr->str_len == 0)
btf->strs_deduped = true;
if (!btf->base_btf && btf->hdr->str_len == 1)
btf->strs_deduped = true;
/* invalidate raw_data representation */
btf_invalidate_raw_data(btf);
return 0;
err_out:
strset__free(set);
free(hdr);
free(types);
return err;
}
/* Find an offset in BTF string section that corresponds to a given string *s*.
* Returns:
* - >0 offset into string section, if string is found;
* - -ENOENT, if string is not in the string section;
* - <0, on any other error.
*/
int btf__find_str(struct btf *btf, const char *s)
{
int off;
if (btf->base_btf) {
off = btf__find_str(btf->base_btf, s);
if (off != -ENOENT)
return off;
}
/* BTF needs to be in a modifiable state to build string lookup index */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
off = strset__find_str(btf->strs_set, s);
if (off < 0)
return libbpf_err(off);
return btf->start_str_off + off;
}
/* Add a string s to the BTF string section.
* Returns:
* - > 0 offset into string section, on success;
* - < 0, on error.
*/
int btf__add_str(struct btf *btf, const char *s)
{
int off;
if (btf->base_btf) {
off = btf__find_str(btf->base_btf, s);
if (off != -ENOENT)
return off;
}
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
off = strset__add_str(btf->strs_set, s);
if (off < 0)
return libbpf_err(off);
btf->hdr->str_len = strset__data_size(btf->strs_set);
return btf->start_str_off + off;
}
static void *btf_add_type_mem(struct btf *btf, size_t add_sz)
{
return libbpf_add_mem(&btf->types_data, &btf->types_data_cap, 1,
btf->hdr->type_len, UINT_MAX, add_sz);
}
static void btf_type_inc_vlen(struct btf_type *t)
{
t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t));
}
static int btf_commit_type(struct btf *btf, int data_sz)
{
int err;
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
if (err)
return libbpf_err(err);
btf->hdr->type_len += data_sz;
btf->hdr->str_off += data_sz;
btf->nr_types++;
return btf->start_id + btf->nr_types - 1;
}
struct btf_pipe {
const struct btf *src;
struct btf *dst;
};
static int btf_rewrite_str(__u32 *str_off, void *ctx)
{
struct btf_pipe *p = ctx;
int off;
if (!*str_off) /* nothing to do for empty strings */
return 0;
off = btf__add_str(p->dst, btf__str_by_offset(p->src, *str_off));
if (off < 0)
return off;
*str_off = off;
return 0;
}
int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type)
{
struct btf_pipe p = { .src = src_btf, .dst = btf };
struct btf_type *t;
int sz, err;
sz = btf_type_size(src_type);
if (sz < 0)
return libbpf_err(sz);
/* deconstruct BTF, if necessary, and invalidate raw_data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
memcpy(t, src_type, sz);
err = btf_type_visit_str_offs(t, btf_rewrite_str, &p);
if (err)
return libbpf_err(err);
return btf_commit_type(btf, sz);
}
static int btf_rewrite_type_ids(__u32 *type_id, void *ctx)
{
struct btf *btf = ctx;
if (!*type_id) /* nothing to do for VOID references */
return 0;
/* we haven't updated btf's type count yet, so
* btf->start_id + btf->nr_types - 1 is the type ID offset we should
* add to all newly added BTF types
*/
*type_id += btf->start_id + btf->nr_types - 1;
return 0;
}
int btf__add_btf(struct btf *btf, const struct btf *src_btf)
{
struct btf_pipe p = { .src = src_btf, .dst = btf };
int data_sz, sz, cnt, i, err, old_strs_len;
__u32 *off;
void *t;
/* appending split BTF isn't supported yet */
if (src_btf->base_btf)
return libbpf_err(-ENOTSUP);
/* deconstruct BTF, if necessary, and invalidate raw_data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
/* remember original strings section size if we have to roll back
* partial strings section changes
*/
old_strs_len = btf->hdr->str_len;
data_sz = src_btf->hdr->type_len;
cnt = btf__type_cnt(src_btf) - 1;
/* pre-allocate enough memory for new types */
t = btf_add_type_mem(btf, data_sz);
if (!t)
return libbpf_err(-ENOMEM);
/* pre-allocate enough memory for type offset index for new types */
off = btf_add_type_offs_mem(btf, cnt);
if (!off)
return libbpf_err(-ENOMEM);
/* bulk copy types data for all types from src_btf */
memcpy(t, src_btf->types_data, data_sz);
for (i = 0; i < cnt; i++) {
sz = btf_type_size(t);
if (sz < 0) {
/* unlikely, has to be corrupted src_btf */
err = sz;
goto err_out;
}
/* fill out type ID to type offset mapping for lookups by type ID */
*off = t - btf->types_data;
/* add, dedup, and remap strings referenced by this BTF type */
err = btf_type_visit_str_offs(t, btf_rewrite_str, &p);
if (err)
goto err_out;
/* remap all type IDs referenced from this BTF type */
err = btf_type_visit_type_ids(t, btf_rewrite_type_ids, btf);
if (err)
goto err_out;
/* go to next type data and type offset index entry */
t += sz;
off++;
}
/* Up until now any of the copied type data was effectively invisible,
* so if we exited early before this point due to error, BTF would be
* effectively unmodified. There would be extra internal memory
* pre-allocated, but it would not be available for querying. But now
* that we've copied and rewritten all the data successfully, we can
* update type count and various internal offsets and sizes to
* "commit" the changes and made them visible to the outside world.
*/
btf->hdr->type_len += data_sz;
btf->hdr->str_off += data_sz;
btf->nr_types += cnt;
/* return type ID of the first added BTF type */
return btf->start_id + btf->nr_types - cnt;
err_out:
/* zero out preallocated memory as if it was just allocated with
* libbpf_add_mem()
*/
memset(btf->types_data + btf->hdr->type_len, 0, data_sz);
memset(btf->strs_data + old_strs_len, 0, btf->hdr->str_len - old_strs_len);
/* and now restore original strings section size; types data size
* wasn't modified, so doesn't need restoring, see big comment above */
btf->hdr->str_len = old_strs_len;
return libbpf_err(err);
}
/*
* Append new BTF_KIND_INT type with:
* - *name* - non-empty, non-NULL type name;
* - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes;
* - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL.
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding)
{
struct btf_type *t;
int sz, name_off;
/* non-empty name */
if (!name || !name[0])
return libbpf_err(-EINVAL);
/* byte_sz must be power of 2 */
if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16)
return libbpf_err(-EINVAL);
if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL))
return libbpf_err(-EINVAL);
/* deconstruct BTF, if necessary, and invalidate raw_data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type) + sizeof(int);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
/* if something goes wrong later, we might end up with an extra string,
* but that shouldn't be a problem, because BTF can't be constructed
* completely anyway and will most probably be just discarded
*/
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
t->name_off = name_off;
t->info = btf_type_info(BTF_KIND_INT, 0, 0);
t->size = byte_sz;
/* set INT info, we don't allow setting legacy bit offset/size */
*(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8);
return btf_commit_type(btf, sz);
}
/*
* Append new BTF_KIND_FLOAT type with:
* - *name* - non-empty, non-NULL type name;
* - *sz* - size of the type, in bytes;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_float(struct btf *btf, const char *name, size_t byte_sz)
{
struct btf_type *t;
int sz, name_off;
/* non-empty name */
if (!name || !name[0])
return libbpf_err(-EINVAL);
/* byte_sz must be one of the explicitly allowed values */
if (byte_sz != 2 && byte_sz != 4 && byte_sz != 8 && byte_sz != 12 &&
byte_sz != 16)
return libbpf_err(-EINVAL);
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
t->name_off = name_off;
t->info = btf_type_info(BTF_KIND_FLOAT, 0, 0);
t->size = byte_sz;
return btf_commit_type(btf, sz);
}
/* it's completely legal to append BTF types with type IDs pointing forward to
* types that haven't been appended yet, so we only make sure that id looks
* sane, we can't guarantee that ID will always be valid
*/
static int validate_type_id(int id)
{
if (id < 0 || id > BTF_MAX_NR_TYPES)
return -EINVAL;
return 0;
}
/* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */
static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id)
{
struct btf_type *t;
int sz, name_off = 0;
if (validate_type_id(ref_type_id))
return libbpf_err(-EINVAL);
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
if (name && name[0]) {
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
}
t->name_off = name_off;
t->info = btf_type_info(kind, 0, 0);
t->type = ref_type_id;
return btf_commit_type(btf, sz);
}
/*
* Append new BTF_KIND_PTR type with:
* - *ref_type_id* - referenced type ID, it might not exist yet;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_ptr(struct btf *btf, int ref_type_id)
{
return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id);
}
/*
* Append new BTF_KIND_ARRAY type with:
* - *index_type_id* - type ID of the type describing array index;
* - *elem_type_id* - type ID of the type describing array element;
* - *nr_elems* - the size of the array;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems)
{
struct btf_type *t;
struct btf_array *a;
int sz;
if (validate_type_id(index_type_id) || validate_type_id(elem_type_id))
return libbpf_err(-EINVAL);
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type) + sizeof(struct btf_array);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
t->name_off = 0;
t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0);
t->size = 0;
a = btf_array(t);
a->type = elem_type_id;
a->index_type = index_type_id;
a->nelems = nr_elems;
return btf_commit_type(btf, sz);
}
/* generic STRUCT/UNION append function */
static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz)
{
struct btf_type *t;
int sz, name_off = 0;
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
if (name && name[0]) {
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
}
/* start out with vlen=0 and no kflag; this will be adjusted when
* adding each member
*/
t->name_off = name_off;
t->info = btf_type_info(kind, 0, 0);
t->size = bytes_sz;
return btf_commit_type(btf, sz);
}
/*
* Append new BTF_KIND_STRUCT type with:
* - *name* - name of the struct, can be NULL or empty for anonymous structs;
* - *byte_sz* - size of the struct, in bytes;
*
* Struct initially has no fields in it. Fields can be added by
* btf__add_field() right after btf__add_struct() succeeds.
*
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz)
{
return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz);
}
/*
* Append new BTF_KIND_UNION type with:
* - *name* - name of the union, can be NULL or empty for anonymous union;
* - *byte_sz* - size of the union, in bytes;
*
* Union initially has no fields in it. Fields can be added by
* btf__add_field() right after btf__add_union() succeeds. All fields
* should have *bit_offset* of 0.
*
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz)
{
return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz);
}
static struct btf_type *btf_last_type(struct btf *btf)
{
return btf_type_by_id(btf, btf__type_cnt(btf) - 1);
}
/*
* Append new field for the current STRUCT/UNION type with:
* - *name* - name of the field, can be NULL or empty for anonymous field;
* - *type_id* - type ID for the type describing field type;
* - *bit_offset* - bit offset of the start of the field within struct/union;
* - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields;
* Returns:
* - 0, on success;
* - <0, on error.
*/
int btf__add_field(struct btf *btf, const char *name, int type_id,
__u32 bit_offset, __u32 bit_size)
{
struct btf_type *t;
struct btf_member *m;
bool is_bitfield;
int sz, name_off = 0;
/* last type should be union/struct */
if (btf->nr_types == 0)
return libbpf_err(-EINVAL);
t = btf_last_type(btf);
if (!btf_is_composite(t))
return libbpf_err(-EINVAL);
if (validate_type_id(type_id))
return libbpf_err(-EINVAL);
/* best-effort bit field offset/size enforcement */
is_bitfield = bit_size || (bit_offset % 8 != 0);
if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff))
return libbpf_err(-EINVAL);
/* only offset 0 is allowed for unions */
if (btf_is_union(t) && bit_offset)
return libbpf_err(-EINVAL);
/* decompose and invalidate raw data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_member);
m = btf_add_type_mem(btf, sz);
if (!m)
return libbpf_err(-ENOMEM);
if (name && name[0]) {
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
}
m->name_off = name_off;
m->type = type_id;
m->offset = bit_offset | (bit_size << 24);
/* btf_add_type_mem can invalidate t pointer */
t = btf_last_type(btf);
/* update parent type's vlen and kflag */
t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t));
btf->hdr->type_len += sz;
btf->hdr->str_off += sz;
return 0;
}
/*
* Append new BTF_KIND_ENUM type with:
* - *name* - name of the enum, can be NULL or empty for anonymous enums;
* - *byte_sz* - size of the enum, in bytes.
*
* Enum initially has no enum values in it (and corresponds to enum forward
* declaration). Enumerator values can be added by btf__add_enum_value()
* immediately after btf__add_enum() succeeds.
*
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz)
{
struct btf_type *t;
int sz, name_off = 0;
/* byte_sz must be power of 2 */
if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8)
return libbpf_err(-EINVAL);
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
if (name && name[0]) {
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
}
/* start out with vlen=0; it will be adjusted when adding enum values */
t->name_off = name_off;
t->info = btf_type_info(BTF_KIND_ENUM, 0, 0);
t->size = byte_sz;
return btf_commit_type(btf, sz);
}
/*
* Append new enum value for the current ENUM type with:
* - *name* - name of the enumerator value, can't be NULL or empty;
* - *value* - integer value corresponding to enum value *name*;
* Returns:
* - 0, on success;
* - <0, on error.
*/
int btf__add_enum_value(struct btf *btf, const char *name, __s64 value)
{
struct btf_type *t;
struct btf_enum *v;
int sz, name_off;
/* last type should be BTF_KIND_ENUM */
if (btf->nr_types == 0)
return libbpf_err(-EINVAL);
t = btf_last_type(btf);
if (!btf_is_enum(t))
return libbpf_err(-EINVAL);
/* non-empty name */
if (!name || !name[0])
return libbpf_err(-EINVAL);
if (value < INT_MIN || value > UINT_MAX)
return libbpf_err(-E2BIG);
/* decompose and invalidate raw data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_enum);
v = btf_add_type_mem(btf, sz);
if (!v)
return libbpf_err(-ENOMEM);
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
v->name_off = name_off;
v->val = value;
/* update parent type's vlen */
t = btf_last_type(btf);
btf_type_inc_vlen(t);
btf->hdr->type_len += sz;
btf->hdr->str_off += sz;
return 0;
}
/*
* Append new BTF_KIND_FWD type with:
* - *name*, non-empty/non-NULL name;
* - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT,
* BTF_FWD_UNION, or BTF_FWD_ENUM;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind)
{
if (!name || !name[0])
return libbpf_err(-EINVAL);
switch (fwd_kind) {
case BTF_FWD_STRUCT:
case BTF_FWD_UNION: {
struct btf_type *t;
int id;
id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0);
if (id <= 0)
return id;
t = btf_type_by_id(btf, id);
t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION);
return id;
}
case BTF_FWD_ENUM:
/* enum forward in BTF currently is just an enum with no enum
* values; we also assume a standard 4-byte size for it
*/
return btf__add_enum(btf, name, sizeof(int));
default:
return libbpf_err(-EINVAL);
}
}
/*
* Append new BTF_KING_TYPEDEF type with:
* - *name*, non-empty/non-NULL name;
* - *ref_type_id* - referenced type ID, it might not exist yet;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id)
{
if (!name || !name[0])
return libbpf_err(-EINVAL);
return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id);
}
/*
* Append new BTF_KIND_VOLATILE type with:
* - *ref_type_id* - referenced type ID, it might not exist yet;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_volatile(struct btf *btf, int ref_type_id)
{
return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id);
}
/*
* Append new BTF_KIND_CONST type with:
* - *ref_type_id* - referenced type ID, it might not exist yet;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_const(struct btf *btf, int ref_type_id)
{
return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id);
}
/*
* Append new BTF_KIND_RESTRICT type with:
* - *ref_type_id* - referenced type ID, it might not exist yet;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_restrict(struct btf *btf, int ref_type_id)
{
return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id);
}
/*
* Append new BTF_KIND_FUNC type with:
* - *name*, non-empty/non-NULL name;
* - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_func(struct btf *btf, const char *name,
enum btf_func_linkage linkage, int proto_type_id)
{
int id;
if (!name || !name[0])
return libbpf_err(-EINVAL);
if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL &&
linkage != BTF_FUNC_EXTERN)
return libbpf_err(-EINVAL);
id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id);
if (id > 0) {
struct btf_type *t = btf_type_by_id(btf, id);
t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0);
}
return libbpf_err(id);
}
/*
* Append new BTF_KIND_FUNC_PROTO with:
* - *ret_type_id* - type ID for return result of a function.
*
* Function prototype initially has no arguments, but they can be added by
* btf__add_func_param() one by one, immediately after
* btf__add_func_proto() succeeded.
*
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_func_proto(struct btf *btf, int ret_type_id)
{
struct btf_type *t;
int sz;
if (validate_type_id(ret_type_id))
return libbpf_err(-EINVAL);
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
/* start out with vlen=0; this will be adjusted when adding enum
* values, if necessary
*/
t->name_off = 0;
t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0);
t->type = ret_type_id;
return btf_commit_type(btf, sz);
}
/*
* Append new function parameter for current FUNC_PROTO type with:
* - *name* - parameter name, can be NULL or empty;
* - *type_id* - type ID describing the type of the parameter.
* Returns:
* - 0, on success;
* - <0, on error.
*/
int btf__add_func_param(struct btf *btf, const char *name, int type_id)
{
struct btf_type *t;
struct btf_param *p;
int sz, name_off = 0;
if (validate_type_id(type_id))
return libbpf_err(-EINVAL);
/* last type should be BTF_KIND_FUNC_PROTO */
if (btf->nr_types == 0)
return libbpf_err(-EINVAL);
t = btf_last_type(btf);
if (!btf_is_func_proto(t))
return libbpf_err(-EINVAL);
/* decompose and invalidate raw data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_param);
p = btf_add_type_mem(btf, sz);
if (!p)
return libbpf_err(-ENOMEM);
if (name && name[0]) {
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
}
p->name_off = name_off;
p->type = type_id;
/* update parent type's vlen */
t = btf_last_type(btf);
btf_type_inc_vlen(t);
btf->hdr->type_len += sz;
btf->hdr->str_off += sz;
return 0;
}
/*
* Append new BTF_KIND_VAR type with:
* - *name* - non-empty/non-NULL name;
* - *linkage* - variable linkage, one of BTF_VAR_STATIC,
* BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN;
* - *type_id* - type ID of the type describing the type of the variable.
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id)
{
struct btf_type *t;
struct btf_var *v;
int sz, name_off;
/* non-empty name */
if (!name || !name[0])
return libbpf_err(-EINVAL);
if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED &&
linkage != BTF_VAR_GLOBAL_EXTERN)
return libbpf_err(-EINVAL);
if (validate_type_id(type_id))
return libbpf_err(-EINVAL);
/* deconstruct BTF, if necessary, and invalidate raw_data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type) + sizeof(struct btf_var);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
t->name_off = name_off;
t->info = btf_type_info(BTF_KIND_VAR, 0, 0);
t->type = type_id;
v = btf_var(t);
v->linkage = linkage;
return btf_commit_type(btf, sz);
}
/*
* Append new BTF_KIND_DATASEC type with:
* - *name* - non-empty/non-NULL name;
* - *byte_sz* - data section size, in bytes.
*
* Data section is initially empty. Variables info can be added with
* btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds.
*
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz)
{
struct btf_type *t;
int sz, name_off;
/* non-empty name */
if (!name || !name[0])
return libbpf_err(-EINVAL);
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
name_off = btf__add_str(btf, name);
if (name_off < 0)
return name_off;
/* start with vlen=0, which will be update as var_secinfos are added */
t->name_off = name_off;
t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0);
t->size = byte_sz;
return btf_commit_type(btf, sz);
}
/*
* Append new data section variable information entry for current DATASEC type:
* - *var_type_id* - type ID, describing type of the variable;
* - *offset* - variable offset within data section, in bytes;
* - *byte_sz* - variable size, in bytes.
*
* Returns:
* - 0, on success;
* - <0, on error.
*/
int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz)
{
struct btf_type *t;
struct btf_var_secinfo *v;
int sz;
/* last type should be BTF_KIND_DATASEC */
if (btf->nr_types == 0)
return libbpf_err(-EINVAL);
t = btf_last_type(btf);
if (!btf_is_datasec(t))
return libbpf_err(-EINVAL);
if (validate_type_id(var_type_id))
return libbpf_err(-EINVAL);
/* decompose and invalidate raw data */
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_var_secinfo);
v = btf_add_type_mem(btf, sz);
if (!v)
return libbpf_err(-ENOMEM);
v->type = var_type_id;
v->offset = offset;
v->size = byte_sz;
/* update parent type's vlen */
t = btf_last_type(btf);
btf_type_inc_vlen(t);
btf->hdr->type_len += sz;
btf->hdr->str_off += sz;
return 0;
}
/*
* Append new BTF_KIND_DECL_TAG type with:
* - *value* - non-empty/non-NULL string;
* - *ref_type_id* - referenced type ID, it might not exist yet;
* - *component_idx* - -1 for tagging reference type, otherwise struct/union
* member or function argument index;
* Returns:
* - >0, type ID of newly added BTF type;
* - <0, on error.
*/
int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
int component_idx)
{
struct btf_type *t;
int sz, value_off;
if (!value || !value[0] || component_idx < -1)
return libbpf_err(-EINVAL);
if (validate_type_id(ref_type_id))
return libbpf_err(-EINVAL);
if (btf_ensure_modifiable(btf))
return libbpf_err(-ENOMEM);
sz = sizeof(struct btf_type) + sizeof(struct btf_decl_tag);
t = btf_add_type_mem(btf, sz);
if (!t)
return libbpf_err(-ENOMEM);
value_off = btf__add_str(btf, value);
if (value_off < 0)
return value_off;
t->name_off = value_off;
t->info = btf_type_info(BTF_KIND_DECL_TAG, 0, false);
t->type = ref_type_id;
btf_decl_tag(t)->component_idx = component_idx;
return btf_commit_type(btf, sz);
}
struct btf_ext_sec_setup_param {
__u32 off;
__u32 len;
__u32 min_rec_size;
struct btf_ext_info *ext_info;
const char *desc;
};
static int btf_ext_setup_info(struct btf_ext *btf_ext,
struct btf_ext_sec_setup_param *ext_sec)
{
const struct btf_ext_info_sec *sinfo;
struct btf_ext_info *ext_info;
__u32 info_left, record_size;
/* The start of the info sec (including the __u32 record_size). */
void *info;
if (ext_sec->len == 0)
return 0;
if (ext_sec->off & 0x03) {
pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n",
ext_sec->desc);
return -EINVAL;
}
info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off;
info_left = ext_sec->len;
if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) {
pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n",
ext_sec->desc, ext_sec->off, ext_sec->len);
return -EINVAL;
}
/* At least a record size */
if (info_left < sizeof(__u32)) {
pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc);
return -EINVAL;
}
/* The record size needs to meet the minimum standard */
record_size = *(__u32 *)info;
if (record_size < ext_sec->min_rec_size ||
record_size & 0x03) {
pr_debug("%s section in .BTF.ext has invalid record size %u\n",
ext_sec->desc, record_size);
return -EINVAL;
}
sinfo = info + sizeof(__u32);
info_left -= sizeof(__u32);
/* If no records, return failure now so .BTF.ext won't be used. */
if (!info_left) {
pr_debug("%s section in .BTF.ext has no records", ext_sec->desc);
return -EINVAL;
}
while (info_left) {
unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
__u64 total_record_size;
__u32 num_records;
if (info_left < sec_hdrlen) {
pr_debug("%s section header is not found in .BTF.ext\n",
ext_sec->desc);
return -EINVAL;
}
num_records = sinfo->num_info;
if (num_records == 0) {
pr_debug("%s section has incorrect num_records in .BTF.ext\n",
ext_sec->desc);
return -EINVAL;
}
total_record_size = sec_hdrlen +
(__u64)num_records * record_size;
if (info_left < total_record_size) {
pr_debug("%s section has incorrect num_records in .BTF.ext\n",
ext_sec->desc);
return -EINVAL;
}
info_left -= total_record_size;
sinfo = (void *)sinfo + total_record_size;
}
ext_info = ext_sec->ext_info;
ext_info->len = ext_sec->len - sizeof(__u32);
ext_info->rec_size = record_size;
ext_info->info = info + sizeof(__u32);
return 0;
}
static int btf_ext_setup_func_info(struct btf_ext *btf_ext)
{
struct btf_ext_sec_setup_param param = {
.off = btf_ext->hdr->func_info_off,
.len = btf_ext->hdr->func_info_len,
.min_rec_size = sizeof(struct bpf_func_info_min),
.ext_info = &btf_ext->func_info,
.desc = "func_info"
};
return btf_ext_setup_info(btf_ext, &param);
}
static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
{
struct btf_ext_sec_setup_param param = {
.off = btf_ext->hdr->line_info_off,
.len = btf_ext->hdr->line_info_len,
.min_rec_size = sizeof(struct bpf_line_info_min),
.ext_info = &btf_ext->line_info,
.desc = "line_info",
};
return btf_ext_setup_info(btf_ext, &param);
}
static int btf_ext_setup_core_relos(struct btf_ext *btf_ext)
{
struct btf_ext_sec_setup_param param = {
.off = btf_ext->hdr->core_relo_off,
.len = btf_ext->hdr->core_relo_len,
.min_rec_size = sizeof(struct bpf_core_relo),
.ext_info = &btf_ext->core_relo_info,
.desc = "core_relo",
};
return btf_ext_setup_info(btf_ext, &param);
}
static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
{
const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
if (data_size < offsetofend(struct btf_ext_header, hdr_len) ||
data_size < hdr->hdr_len) {
pr_debug("BTF.ext header not found");
return -EINVAL;
}
if (hdr->magic == bswap_16(BTF_MAGIC)) {
pr_warn("BTF.ext in non-native endianness is not supported\n");
return -ENOTSUP;
} else if (hdr->magic != BTF_MAGIC) {
pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic);
return -EINVAL;
}
if (hdr->version != BTF_VERSION) {
pr_debug("Unsupported BTF.ext version:%u\n", hdr->version);
return -ENOTSUP;
}
if (hdr->flags) {
pr_debug("Unsupported BTF.ext flags:%x\n", hdr->flags);
return -ENOTSUP;
}
if (data_size == hdr->hdr_len) {
pr_debug("BTF.ext has no data\n");
return -EINVAL;
}
return 0;
}
void btf_ext__free(struct btf_ext *btf_ext)
{
if (IS_ERR_OR_NULL(btf_ext))
return;
free(btf_ext->data);
free(btf_ext);
}
struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
{
struct btf_ext *btf_ext;
int err;
err = btf_ext_parse_hdr(data, size);
if (err)
return libbpf_err_ptr(err);
btf_ext = calloc(1, sizeof(struct btf_ext));
if (!btf_ext)
return libbpf_err_ptr(-ENOMEM);
btf_ext->data_size = size;
btf_ext->data = malloc(size);
if (!btf_ext->data) {
err = -ENOMEM;
goto done;
}
memcpy(btf_ext->data, data, size);
if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, line_info_len)) {
err = -EINVAL;
goto done;
}
err = btf_ext_setup_func_info(btf_ext);
if (err)
goto done;
err = btf_ext_setup_line_info(btf_ext);
if (err)
goto done;
if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) {
err = -EINVAL;
goto done;
}
err = btf_ext_setup_core_relos(btf_ext);
if (err)
goto done;
done:
if (err) {
btf_ext__free(btf_ext);
return libbpf_err_ptr(err);
}
return btf_ext;
}
const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size)
{
*size = btf_ext->data_size;
return btf_ext->data;
}
static int btf_ext_reloc_info(const struct btf *btf,
const struct btf_ext_info *ext_info,
const char *sec_name, __u32 insns_cnt,
void **info, __u32 *cnt)
{
__u32 sec_hdrlen = sizeof(struct btf_ext_info_sec);
__u32 i, record_size, existing_len, records_len;
struct btf_ext_info_sec *sinfo;
const char *info_sec_name;
__u64 remain_len