mirror of https://gitee.com/openkylin/linux.git
4475 lines
114 KiB
C
4475 lines
114 KiB
C
// 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"
|
|
|
|
#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__get_raw_data(), at which point
|
|
* raw_data will contain a contiguous copy of header, types, and
|
|
* strings:
|
|
*
|
|
* +----------+ +---------+ +-----------+
|
|
* | Header | | Types | | Strings |
|
|
* +----------+ +---------+ +-----------+
|
|
* ^ ^ ^
|
|
* | | |
|
|
* hdr | |
|
|
* types_data----+ |
|
|
* strs_data------------------+
|
|
*
|
|
* +----------+---------+-----------+
|
|
* | 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 */
|
|
__u32 *type_offs;
|
|
size_t type_offs_cap;
|
|
__u32 nr_types;
|
|
|
|
void *strs_data;
|
|
size_t strs_data_cap; /* used size stored in hdr->str_len */
|
|
|
|
/* lookup index for each unique string in strings section */
|
|
struct hashmap *strs_hash;
|
|
/* 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 *btf_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 btf_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 = btf_add_mem(data, cap_cnt, elem_sz, *cap_cnt, SIZE_MAX, need_cnt - *cap_cnt);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off)
|
|
{
|
|
__u32 *p;
|
|
|
|
p = btf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32),
|
|
btf->nr_types + 1, BTF_MAX_NR_TYPES, 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;
|
|
}
|
|
|
|
meta_left = btf->raw_size - sizeof(*hdr);
|
|
if (!meta_left) {
|
|
pr_debug("BTF has no data\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (meta_left < hdr->type_off) {
|
|
pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (meta_left < hdr->str_off) {
|
|
pr_debug("Invalid BTF string section offset:%u\n", hdr->str_off);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (hdr->type_off >= hdr->str_off) {
|
|
pr_debug("BTF type section offset >= string section offset. No type?\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (hdr->type_off & 0x02) {
|
|
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 (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET ||
|
|
start[0] || end[-1]) {
|
|
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:
|
|
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);
|
|
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:
|
|
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;
|
|
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, i = 0, type_size;
|
|
|
|
/* VOID (type_id == 0) is specially handled by btf__get_type_by_id(),
|
|
* so ensure we can never properly use its offset from index by
|
|
* setting it to a large value
|
|
*/
|
|
err = btf_add_type_idx_entry(btf, UINT_MAX);
|
|
if (err)
|
|
return err;
|
|
|
|
while (next_type + sizeof(struct btf_type) <= end_type) {
|
|
i++;
|
|
|
|
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", i);
|
|
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->nr_types;
|
|
}
|
|
|
|
/* internal helper returning non-const pointer to a type */
|
|
static struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id)
|
|
{
|
|
if (type_id == 0)
|
|
return &btf_void;
|
|
|
|
return btf->types_data + btf->type_offs[type_id];
|
|
}
|
|
|
|
const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
|
|
{
|
|
if (type_id > btf->nr_types)
|
|
return 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;
|
|
|
|
for (i = 1; i <= btf->nr_types; 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 -EINVAL;
|
|
btf->ptr_sz = ptr_sz;
|
|
return 0;
|
|
}
|
|
|
|
static bool is_host_big_endian(void)
|
|
{
|
|
#if __BYTE_ORDER == __LITTLE_ENDIAN
|
|
return false;
|
|
#elif __BYTE_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 -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:
|
|
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:
|
|
type_id = t->type;
|
|
break;
|
|
case BTF_KIND_ARRAY:
|
|
array = btf_array(t);
|
|
if (nelems && array->nelems > UINT32_MAX / nelems)
|
|
return -E2BIG;
|
|
nelems *= array->nelems;
|
|
type_id = array->type;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
t = btf__type_by_id(btf, type_id);
|
|
}
|
|
|
|
done:
|
|
if (size < 0)
|
|
return -EINVAL;
|
|
if (nelems && size > UINT32_MAX / nelems)
|
|
return -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:
|
|
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 align;
|
|
max_align = max(max_align, align);
|
|
}
|
|
|
|
return max_align;
|
|
}
|
|
default:
|
|
pr_warn("unsupported BTF_KIND:%u\n", btf_kind(t));
|
|
return 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 -EINVAL;
|
|
|
|
return type_id;
|
|
}
|
|
|
|
__s32 btf__find_by_name(const struct btf *btf, const char *type_name)
|
|
{
|
|
__u32 i;
|
|
|
|
if (!strcmp(type_name, "void"))
|
|
return 0;
|
|
|
|
for (i = 1; i <= btf->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 -ENOENT;
|
|
}
|
|
|
|
__s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
|
|
__u32 kind)
|
|
{
|
|
__u32 i;
|
|
|
|
if (kind == BTF_KIND_UNKN || !strcmp(type_name, "void"))
|
|
return 0;
|
|
|
|
for (i = 1; i <= btf->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 -ENOENT;
|
|
}
|
|
|
|
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);
|
|
free(btf->strs_data);
|
|
}
|
|
free(btf->raw_data);
|
|
free(btf->raw_data_swapped);
|
|
free(btf->type_offs);
|
|
free(btf);
|
|
}
|
|
|
|
struct btf *btf__new_empty(void)
|
|
{
|
|
struct btf *btf;
|
|
|
|
btf = calloc(1, sizeof(*btf));
|
|
if (!btf)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
btf->fd = -1;
|
|
btf->ptr_sz = sizeof(void *);
|
|
btf->swapped_endian = false;
|
|
|
|
/* +1 for empty string at offset 0 */
|
|
btf->raw_size = sizeof(struct btf_header) + 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 = 1; /* empty string at offset 0 */
|
|
|
|
return btf;
|
|
}
|
|
|
|
struct btf *btf__new(const void *data, __u32 size)
|
|
{
|
|
struct btf *btf;
|
|
int err;
|
|
|
|
btf = calloc(1, sizeof(struct btf));
|
|
if (!btf)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
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;
|
|
|
|
btf->fd = -1;
|
|
|
|
done:
|
|
if (err) {
|
|
btf__free(btf);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
return btf;
|
|
}
|
|
|
|
struct btf *btf__parse_elf(const char *path, 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;
|
|
|
|
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);
|
|
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_rawdata(elf_getscn(elf, ehdr.e_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, ehdr.e_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);
|
|
if (IS_ERR(btf))
|
|
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);
|
|
if (IS_ERR(*btf_ext))
|
|
goto done;
|
|
} else if (btf_ext) {
|
|
*btf_ext = NULL;
|
|
}
|
|
done:
|
|
if (elf)
|
|
elf_end(elf);
|
|
close(fd);
|
|
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
/*
|
|
* btf is always parsed before btf_ext, so no need to clean up
|
|
* btf_ext, if btf loading failed
|
|
*/
|
|
if (IS_ERR(btf))
|
|
return btf;
|
|
if (btf_ext && IS_ERR(*btf_ext)) {
|
|
btf__free(btf);
|
|
err = PTR_ERR(*btf_ext);
|
|
return ERR_PTR(err);
|
|
}
|
|
return btf;
|
|
}
|
|
|
|
struct btf *btf__parse_raw(const char *path)
|
|
{
|
|
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);
|
|
|
|
err_out:
|
|
free(data);
|
|
if (f)
|
|
fclose(f);
|
|
return err ? ERR_PTR(err) : btf;
|
|
}
|
|
|
|
struct btf *btf__parse(const char *path, struct btf_ext **btf_ext)
|
|
{
|
|
struct btf *btf;
|
|
|
|
if (btf_ext)
|
|
*btf_ext = NULL;
|
|
|
|
btf = btf__parse_raw(path);
|
|
if (!IS_ERR(btf) || PTR_ERR(btf) != -EPROTO)
|
|
return btf;
|
|
|
|
return btf__parse_elf(path, btf_ext);
|
|
}
|
|
|
|
static int compare_vsi_off(const void *_a, const void *_b)
|
|
{
|
|
const struct btf_var_secinfo *a = _a;
|
|
const struct btf_var_secinfo *b = _b;
|
|
|
|
return a->offset - b->offset;
|
|
}
|
|
|
|
static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf,
|
|
struct btf_type *t)
|
|
{
|
|
__u32 size = 0, off = 0, i, vars = btf_vlen(t);
|
|
const char *name = btf__name_by_offset(btf, t->name_off);
|
|
const struct btf_type *t_var;
|
|
struct btf_var_secinfo *vsi;
|
|
const struct btf_var *var;
|
|
int ret;
|
|
|
|
if (!name) {
|
|
pr_debug("No name found in string section for DATASEC kind.\n");
|
|
return -ENOENT;
|
|
}
|
|
|
|
/* .extern datasec size and var offsets were set correctly during
|
|
* extern collection step, so just skip straight to sorting variables
|
|
*/
|
|
if (t->size)
|
|
goto sort_vars;
|
|
|
|
ret = bpf_object__section_size(obj, name, &size);
|
|
if (ret || !size || (t->size && t->size != size)) {
|
|
pr_debug("Invalid size for section %s: %u bytes\n", name, size);
|
|
return -ENOENT;
|
|
}
|
|
|
|
t->size = size;
|
|
|
|
for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) {
|
|
t_var = btf__type_by_id(btf, vsi->type);
|
|
var = btf_var(t_var);
|
|
|
|
if (!btf_is_var(t_var)) {
|
|
pr_debug("Non-VAR type seen in section %s\n", name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (var->linkage == BTF_VAR_STATIC)
|
|
continue;
|
|
|
|
name = btf__name_by_offset(btf, t_var->name_off);
|
|
if (!name) {
|
|
pr_debug("No name found in string section for VAR kind\n");
|
|
return -ENOENT;
|
|
}
|
|
|
|
ret = bpf_object__variable_offset(obj, name, &off);
|
|
if (ret) {
|
|
pr_debug("No offset found in symbol table for VAR %s\n",
|
|
name);
|
|
return -ENOENT;
|
|
}
|
|
|
|
vsi->offset = off;
|
|
}
|
|
|
|
sort_vars:
|
|
qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off);
|
|
return 0;
|
|
}
|
|
|
|
int btf__finalize_data(struct bpf_object *obj, struct btf *btf)
|
|
{
|
|
int err = 0;
|
|
__u32 i;
|
|
|
|
for (i = 1; i <= btf->nr_types; i++) {
|
|
struct btf_type *t = btf_type_by_id(btf, i);
|
|
|
|
/* Loader needs to fix up some of the things compiler
|
|
* couldn't get its hands on while emitting BTF. This
|
|
* is section size and global variable offset. We use
|
|
* the info from the ELF itself for this purpose.
|
|
*/
|
|
if (btf_is_datasec(t)) {
|
|
err = btf_fixup_datasec(obj, btf, t);
|
|
if (err)
|
|
break;
|
|
}
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian);
|
|
|
|
int btf__load(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 -EEXIST;
|
|
|
|
retry_load:
|
|
if (log_buf_size) {
|
|
log_buf = malloc(log_buf_size);
|
|
if (!log_buf)
|
|
return -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 err;
|
|
}
|
|
|
|
int btf__fd(const struct btf *btf)
|
|
{
|
|
return btf->fd;
|
|
}
|
|
|
|
void btf__set_fd(struct btf *btf, int fd)
|
|
{
|
|
btf->fd = fd;
|
|
}
|
|
|
|
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 = 1; 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, hdr->str_len);
|
|
p += hdr->str_len;
|
|
|
|
*size = data_sz;
|
|
return data;
|
|
err_out:
|
|
free(data);
|
|
return NULL;
|
|
}
|
|
|
|
const void *btf__get_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 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;
|
|
}
|
|
|
|
const char *btf__str_by_offset(const struct btf *btf, __u32 offset)
|
|
{
|
|
if (offset < btf->hdr->str_len)
|
|
return btf->strs_data + offset;
|
|
else
|
|
return NULL;
|
|
}
|
|
|
|
const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
|
|
{
|
|
return btf__str_by_offset(btf, offset);
|
|
}
|
|
|
|
int btf__get_from_id(__u32 id, struct btf **btf)
|
|
{
|
|
struct bpf_btf_info btf_info = { 0 };
|
|
__u32 len = sizeof(btf_info);
|
|
__u32 last_size;
|
|
int btf_fd;
|
|
void *ptr;
|
|
int err;
|
|
|
|
err = 0;
|
|
*btf = NULL;
|
|
btf_fd = bpf_btf_get_fd_by_id(id);
|
|
if (btf_fd < 0)
|
|
return 0;
|
|
|
|
/* 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.
|
|
*/
|
|
btf_info.btf_size = 4096;
|
|
last_size = btf_info.btf_size;
|
|
ptr = malloc(last_size);
|
|
if (!ptr) {
|
|
err = -ENOMEM;
|
|
goto exit_free;
|
|
}
|
|
|
|
memset(ptr, 0, last_size);
|
|
btf_info.btf = ptr_to_u64(ptr);
|
|
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) {
|
|
err = -ENOMEM;
|
|
goto exit_free;
|
|
}
|
|
ptr = temp_ptr;
|
|
memset(ptr, 0, last_size);
|
|
btf_info.btf = ptr_to_u64(ptr);
|
|
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
|
|
}
|
|
|
|
if (err || btf_info.btf_size > last_size) {
|
|
err = errno;
|
|
goto exit_free;
|
|
}
|
|
|
|
*btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size);
|
|
if (IS_ERR(*btf)) {
|
|
err = PTR_ERR(*btf);
|
|
*btf = NULL;
|
|
}
|
|
|
|
exit_free:
|
|
close(btf_fd);
|
|
free(ptr);
|
|
|
|
return err;
|
|
}
|
|
|
|
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 -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 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 -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 -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 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 -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 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 -EINVAL;
|
|
}
|
|
|
|
*key_type_id = key->type;
|
|
*value_type_id = value->type;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static size_t strs_hash_fn(const void *key, void *ctx)
|
|
{
|
|
struct btf *btf = ctx;
|
|
const char *str = btf->strs_data + (long)key;
|
|
|
|
return str_hash(str);
|
|
}
|
|
|
|
static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx)
|
|
{
|
|
struct btf *btf = ctx;
|
|
const char *str1 = btf->strs_data + (long)key1;
|
|
const char *str2 = btf->strs_data + (long)key2;
|
|
|
|
return strcmp(str1, str2) == 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, *strs, *strs_end, *s;
|
|
struct hashmap *hash = NULL;
|
|
long off;
|
|
int err;
|
|
|
|
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);
|
|
strs = malloc(btf->hdr->str_len);
|
|
if (!hdr || !types || !strs)
|
|
goto err_out;
|
|
|
|
memcpy(hdr, btf->hdr, btf->hdr->hdr_len);
|
|
memcpy(types, btf->types_data, btf->hdr->type_len);
|
|
memcpy(strs, btf->strs_data, btf->hdr->str_len);
|
|
|
|
/* build lookup index for all strings */
|
|
hash = hashmap__new(strs_hash_fn, strs_hash_equal_fn, btf);
|
|
if (IS_ERR(hash)) {
|
|
err = PTR_ERR(hash);
|
|
hash = NULL;
|
|
goto err_out;
|
|
}
|
|
|
|
strs_end = strs + btf->hdr->str_len;
|
|
for (off = 0, s = strs; s < strs_end; off += strlen(s) + 1, s = strs + off) {
|
|
/* hashmap__add() returns EEXIST if string with the same
|
|
* content already is in the hash map
|
|
*/
|
|
err = hashmap__add(hash, (void *)off, (void *)off);
|
|
if (err == -EEXIST)
|
|
continue; /* duplicate */
|
|
if (err)
|
|
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 = strs;
|
|
btf->strs_data_cap = btf->hdr->str_len;
|
|
btf->strs_hash = hash;
|
|
/* if BTF was created from scratch, all strings are guaranteed to be
|
|
* unique and deduplicated
|
|
*/
|
|
btf->strs_deduped = btf->hdr->str_len <= 1;
|
|
|
|
/* invalidate raw_data representation */
|
|
btf_invalidate_raw_data(btf);
|
|
|
|
return 0;
|
|
|
|
err_out:
|
|
hashmap__free(hash);
|
|
free(hdr);
|
|
free(types);
|
|
free(strs);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void *btf_add_str_mem(struct btf *btf, size_t add_sz)
|
|
{
|
|
return btf_add_mem(&btf->strs_data, &btf->strs_data_cap, 1,
|
|
btf->hdr->str_len, BTF_MAX_STR_OFFSET, add_sz);
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
long old_off, new_off, len;
|
|
void *p;
|
|
|
|
/* BTF needs to be in a modifiable state to build string lookup index */
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
/* see btf__add_str() for why we do this */
|
|
len = strlen(s) + 1;
|
|
p = btf_add_str_mem(btf, len);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
|
|
new_off = btf->hdr->str_len;
|
|
memcpy(p, s, len);
|
|
|
|
if (hashmap__find(btf->strs_hash, (void *)new_off, (void **)&old_off))
|
|
return old_off;
|
|
|
|
return -ENOENT;
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
long old_off, new_off, len;
|
|
void *p;
|
|
int err;
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
/* Hashmap keys are always offsets within btf->strs_data, so to even
|
|
* look up some string from the "outside", we need to first append it
|
|
* at the end, so that it can be addressed with an offset. Luckily,
|
|
* until btf->hdr->str_len is incremented, that string is just a piece
|
|
* of garbage for the rest of BTF code, so no harm, no foul. On the
|
|
* other hand, if the string is unique, it's already appended and
|
|
* ready to be used, only a simple btf->hdr->str_len increment away.
|
|
*/
|
|
len = strlen(s) + 1;
|
|
p = btf_add_str_mem(btf, len);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
|
|
new_off = btf->hdr->str_len;
|
|
memcpy(p, s, len);
|
|
|
|
/* Now attempt to add the string, but only if the string with the same
|
|
* contents doesn't exist already (HASHMAP_ADD strategy). If such
|
|
* string exists, we'll get its offset in old_off (that's old_key).
|
|
*/
|
|
err = hashmap__insert(btf->strs_hash, (void *)new_off, (void *)new_off,
|
|
HASHMAP_ADD, (const void **)&old_off, NULL);
|
|
if (err == -EEXIST)
|
|
return old_off; /* duplicated string, return existing offset */
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->str_len += len; /* new unique string, adjust data length */
|
|
return new_off;
|
|
}
|
|
|
|
static void *btf_add_type_mem(struct btf *btf, size_t add_sz)
|
|
{
|
|
return btf_add_mem(&btf->types_data, &btf->types_data_cap, 1,
|
|
btf->hdr->type_len, UINT_MAX, add_sz);
|
|
}
|
|
|
|
static __u32 btf_type_info(int kind, int vlen, int kflag)
|
|
{
|
|
return (kflag << 31) | (kind << 24) | vlen;
|
|
}
|
|
|
|
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));
|
|
}
|
|
|
|
/*
|
|
* 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, err, name_off;
|
|
|
|
/* non-empty name */
|
|
if (!name || !name[0])
|
|
return -EINVAL;
|
|
/* byte_sz must be power of 2 */
|
|
if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16)
|
|
return -EINVAL;
|
|
if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL))
|
|
return -EINVAL;
|
|
|
|
/* deconstruct BTF, if necessary, and invalidate raw_data */
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type) + sizeof(int);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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);
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/* 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, err;
|
|
|
|
if (validate_type_id(ref_type_id))
|
|
return -EINVAL;
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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;
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/*
|
|
* 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, err;
|
|
|
|
if (validate_type_id(index_type_id) || validate_type_id(elem_type_id))
|
|
return -EINVAL;
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type) + sizeof(struct btf_array);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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;
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/* 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, err, name_off = 0;
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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;
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
/*
|
|
* 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 -EINVAL;
|
|
t = btf_type_by_id(btf, btf->nr_types);
|
|
if (!btf_is_composite(t))
|
|
return -EINVAL;
|
|
|
|
if (validate_type_id(type_id))
|
|
return -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 -EINVAL;
|
|
|
|
/* only offset 0 is allowed for unions */
|
|
if (btf_is_union(t) && bit_offset)
|
|
return -EINVAL;
|
|
|
|
/* decompose and invalidate raw data */
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_member);
|
|
m = btf_add_type_mem(btf, sz);
|
|
if (!m)
|
|
return -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_type_by_id(btf, btf->nr_types);
|
|
/* 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, err, name_off = 0;
|
|
|
|
/* byte_sz must be power of 2 */
|
|
if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8)
|
|
return -EINVAL;
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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;
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/*
|
|
* 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 -EINVAL;
|
|
t = btf_type_by_id(btf, btf->nr_types);
|
|
if (!btf_is_enum(t))
|
|
return -EINVAL;
|
|
|
|
/* non-empty name */
|
|
if (!name || !name[0])
|
|
return -EINVAL;
|
|
if (value < INT_MIN || value > UINT_MAX)
|
|
return -E2BIG;
|
|
|
|
/* decompose and invalidate raw data */
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_enum);
|
|
v = btf_add_type_mem(btf, sz);
|
|
if (!v)
|
|
return -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_type_by_id(btf, btf->nr_types);
|
|
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 -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 -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 -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 -EINVAL;
|
|
if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL &&
|
|
linkage != BTF_FUNC_EXTERN)
|
|
return -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 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, err;
|
|
|
|
if (validate_type_id(ret_type_id))
|
|
return -EINVAL;
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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;
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/*
|
|
* 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 -EINVAL;
|
|
|
|
/* last type should be BTF_KIND_FUNC_PROTO */
|
|
if (btf->nr_types == 0)
|
|
return -EINVAL;
|
|
t = btf_type_by_id(btf, btf->nr_types);
|
|
if (!btf_is_func_proto(t))
|
|
return -EINVAL;
|
|
|
|
/* decompose and invalidate raw data */
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_param);
|
|
p = btf_add_type_mem(btf, sz);
|
|
if (!p)
|
|
return -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_type_by_id(btf, btf->nr_types);
|
|
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, err, name_off;
|
|
|
|
/* non-empty name */
|
|
if (!name || !name[0])
|
|
return -EINVAL;
|
|
if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED &&
|
|
linkage != BTF_VAR_GLOBAL_EXTERN)
|
|
return -EINVAL;
|
|
if (validate_type_id(type_id))
|
|
return -EINVAL;
|
|
|
|
/* deconstruct BTF, if necessary, and invalidate raw_data */
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type) + sizeof(struct btf_var);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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;
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/*
|
|
* 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, err, name_off;
|
|
|
|
/* non-empty name */
|
|
if (!name || !name[0])
|
|
return -EINVAL;
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_type);
|
|
t = btf_add_type_mem(btf, sz);
|
|
if (!t)
|
|
return -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;
|
|
|
|
err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
|
|
if (err)
|
|
return err;
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
btf->nr_types++;
|
|
return btf->nr_types;
|
|
}
|
|
|
|
/*
|
|
* 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 -EINVAL;
|
|
t = btf_type_by_id(btf, btf->nr_types);
|
|
if (!btf_is_datasec(t))
|
|
return -EINVAL;
|
|
|
|
if (validate_type_id(var_type_id))
|
|
return -EINVAL;
|
|
|
|
/* decompose and invalidate raw data */
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
sz = sizeof(struct btf_var_secinfo);
|
|
v = btf_add_type_mem(btf, sz);
|
|
if (!v)
|
|
return -ENOMEM;
|
|
|
|
v->type = var_type_id;
|
|
v->offset = offset;
|
|
v->size = byte_sz;
|
|
|
|
/* update parent type's vlen */
|
|
t = btf_type_by_id(btf, btf->nr_types);
|
|
btf_type_inc_vlen(t);
|
|
|
|
btf->hdr->type_len += sz;
|
|
btf->hdr->str_off += sz;
|
|
return 0;
|
|
}
|
|
|
|
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, ¶m);
|
|
}
|
|
|
|
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, ¶m);
|
|
}
|
|
|
|
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, ¶m);
|
|
}
|
|
|
|
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 ERR_PTR(err);
|
|
|
|
btf_ext = calloc(1, sizeof(struct btf_ext));
|
|
if (!btf_ext)
|
|
return 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))
|
|
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))
|
|
goto done;
|
|
err = btf_ext_setup_core_relos(btf_ext);
|
|
if (err)
|
|
goto done;
|
|
|
|
done:
|
|
if (err) {
|
|
btf_ext__free(btf_ext);
|
|
return 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;
|
|
void *data;
|
|
|
|
record_size = ext_info->rec_size;
|
|
sinfo = ext_info->info;
|
|
remain_len = ext_info->len;
|
|
while (remain_len > 0) {
|
|
records_len = sinfo->num_info * record_size;
|
|
info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off);
|
|
if (strcmp(info_sec_name, sec_name)) {
|
|
remain_len -= sec_hdrlen + records_len;
|
|
sinfo = (void *)sinfo + sec_hdrlen + records_len;
|
|
continue;
|
|
}
|
|
|
|
existing_len = (*cnt) * record_size;
|
|
data = realloc(*info, existing_len + records_len);
|
|
if (!data)
|
|
return -ENOMEM;
|
|
|
|
memcpy(data + existing_len, sinfo->data, records_len);
|
|
/* adjust insn_off only, the rest data will be passed
|
|
* to the kernel.
|
|
*/
|
|
for (i = 0; i < sinfo->num_info; i++) {
|
|
__u32 *insn_off;
|
|
|
|
insn_off = data + existing_len + (i * record_size);
|
|
*insn_off = *insn_off / sizeof(struct bpf_insn) +
|
|
insns_cnt;
|
|
}
|
|
*info = data;
|
|
*cnt += sinfo->num_info;
|
|
return 0;
|
|
}
|
|
|
|
return -ENOENT;
|
|
}
|
|
|
|
int btf_ext__reloc_func_info(const struct btf *btf,
|
|
const struct btf_ext *btf_ext,
|
|
const char *sec_name, __u32 insns_cnt,
|
|
void **func_info, __u32 *cnt)
|
|
{
|
|
return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name,
|
|
insns_cnt, func_info, cnt);
|
|
}
|
|
|
|
int btf_ext__reloc_line_info(const struct btf *btf,
|
|
const struct btf_ext *btf_ext,
|
|
const char *sec_name, __u32 insns_cnt,
|
|
void **line_info, __u32 *cnt)
|
|
{
|
|
return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name,
|
|
insns_cnt, line_info, cnt);
|
|
}
|
|
|
|
__u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext)
|
|
{
|
|
return btf_ext->func_info.rec_size;
|
|
}
|
|
|
|
__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext)
|
|
{
|
|
return btf_ext->line_info.rec_size;
|
|
}
|
|
|
|
struct btf_dedup;
|
|
|
|
static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
|
|
const struct btf_dedup_opts *opts);
|
|
static void btf_dedup_free(struct btf_dedup *d);
|
|
static int btf_dedup_strings(struct btf_dedup *d);
|
|
static int btf_dedup_prim_types(struct btf_dedup *d);
|
|
static int btf_dedup_struct_types(struct btf_dedup *d);
|
|
static int btf_dedup_ref_types(struct btf_dedup *d);
|
|
static int btf_dedup_compact_types(struct btf_dedup *d);
|
|
static int btf_dedup_remap_types(struct btf_dedup *d);
|
|
|
|
/*
|
|
* Deduplicate BTF types and strings.
|
|
*
|
|
* BTF dedup algorithm takes as an input `struct btf` representing `.BTF` ELF
|
|
* section with all BTF type descriptors and string data. It overwrites that
|
|
* memory in-place with deduplicated types and strings without any loss of
|
|
* information. If optional `struct btf_ext` representing '.BTF.ext' ELF section
|
|
* is provided, all the strings referenced from .BTF.ext section are honored
|
|
* and updated to point to the right offsets after deduplication.
|
|
*
|
|
* If function returns with error, type/string data might be garbled and should
|
|
* be discarded.
|
|
*
|
|
* More verbose and detailed description of both problem btf_dedup is solving,
|
|
* as well as solution could be found at:
|
|
* https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html
|
|
*
|
|
* Problem description and justification
|
|
* =====================================
|
|
*
|
|
* BTF type information is typically emitted either as a result of conversion
|
|
* from DWARF to BTF or directly by compiler. In both cases, each compilation
|
|
* unit contains information about a subset of all the types that are used
|
|
* in an application. These subsets are frequently overlapping and contain a lot
|
|
* of duplicated information when later concatenated together into a single
|
|
* binary. This algorithm ensures that each unique type is represented by single
|
|
* BTF type descriptor, greatly reducing resulting size of BTF data.
|
|
*
|
|
* Compilation unit isolation and subsequent duplication of data is not the only
|
|
* problem. The same type hierarchy (e.g., struct and all the type that struct
|
|
* references) in different compilation units can be represented in BTF to
|
|
* various degrees of completeness (or, rather, incompleteness) due to
|
|
* struct/union forward declarations.
|
|
*
|
|
* Let's take a look at an example, that we'll use to better understand the
|
|
* problem (and solution). Suppose we have two compilation units, each using
|
|
* same `struct S`, but each of them having incomplete type information about
|
|
* struct's fields:
|
|
*
|
|
* // CU #1:
|
|
* struct S;
|
|
* struct A {
|
|
* int a;
|
|
* struct A* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct B;
|
|
* struct S {
|
|
* struct A* a_ptr;
|
|
* struct B* b_ptr;
|
|
* };
|
|
*
|
|
* // CU #2:
|
|
* struct S;
|
|
* struct A;
|
|
* struct B {
|
|
* int b;
|
|
* struct B* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct S {
|
|
* struct A* a_ptr;
|
|
* struct B* b_ptr;
|
|
* };
|
|
*
|
|
* In case of CU #1, BTF data will know only that `struct B` exist (but no
|
|
* more), but will know the complete type information about `struct A`. While
|
|
* for CU #2, it will know full type information about `struct B`, but will
|
|
* only know about forward declaration of `struct A` (in BTF terms, it will
|
|
* have `BTF_KIND_FWD` type descriptor with name `B`).
|
|
*
|
|
* This compilation unit isolation means that it's possible that there is no
|
|
* single CU with complete type information describing structs `S`, `A`, and
|
|
* `B`. Also, we might get tons of duplicated and redundant type information.
|
|
*
|
|
* Additional complication we need to keep in mind comes from the fact that
|
|
* types, in general, can form graphs containing cycles, not just DAGs.
|
|
*
|
|
* While algorithm does deduplication, it also merges and resolves type
|
|
* information (unless disabled throught `struct btf_opts`), whenever possible.
|
|
* E.g., in the example above with two compilation units having partial type
|
|
* information for structs `A` and `B`, the output of algorithm will emit
|
|
* a single copy of each BTF type that describes structs `A`, `B`, and `S`
|
|
* (as well as type information for `int` and pointers), as if they were defined
|
|
* in a single compilation unit as:
|
|
*
|
|
* struct A {
|
|
* int a;
|
|
* struct A* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct B {
|
|
* int b;
|
|
* struct B* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct S {
|
|
* struct A* a_ptr;
|
|
* struct B* b_ptr;
|
|
* };
|
|
*
|
|
* Algorithm summary
|
|
* =================
|
|
*
|
|
* Algorithm completes its work in 6 separate passes:
|
|
*
|
|
* 1. Strings deduplication.
|
|
* 2. Primitive types deduplication (int, enum, fwd).
|
|
* 3. Struct/union types deduplication.
|
|
* 4. Reference types deduplication (pointers, typedefs, arrays, funcs, func
|
|
* protos, and const/volatile/restrict modifiers).
|
|
* 5. Types compaction.
|
|
* 6. Types remapping.
|
|
*
|
|
* Algorithm determines canonical type descriptor, which is a single
|
|
* representative type for each truly unique type. This canonical type is the
|
|
* one that will go into final deduplicated BTF type information. For
|
|
* struct/unions, it is also the type that algorithm will merge additional type
|
|
* information into (while resolving FWDs), as it discovers it from data in
|
|
* other CUs. Each input BTF type eventually gets either mapped to itself, if
|
|
* that type is canonical, or to some other type, if that type is equivalent
|
|
* and was chosen as canonical representative. This mapping is stored in
|
|
* `btf_dedup->map` array. This map is also used to record STRUCT/UNION that
|
|
* FWD type got resolved to.
|
|
*
|
|
* To facilitate fast discovery of canonical types, we also maintain canonical
|
|
* index (`btf_dedup->dedup_table`), which maps type descriptor's signature hash
|
|
* (i.e., hashed kind, name, size, fields, etc) into a list of canonical types
|
|
* that match that signature. With sufficiently good choice of type signature
|
|
* hashing function, we can limit number of canonical types for each unique type
|
|
* signature to a very small number, allowing to find canonical type for any
|
|
* duplicated type very quickly.
|
|
*
|
|
* Struct/union deduplication is the most critical part and algorithm for
|
|
* deduplicating structs/unions is described in greater details in comments for
|
|
* `btf_dedup_is_equiv` function.
|
|
*/
|
|
int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
|
|
const struct btf_dedup_opts *opts)
|
|
{
|
|
struct btf_dedup *d = btf_dedup_new(btf, btf_ext, opts);
|
|
int err;
|
|
|
|
if (IS_ERR(d)) {
|
|
pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d));
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (btf_ensure_modifiable(btf))
|
|
return -ENOMEM;
|
|
|
|
err = btf_dedup_strings(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_strings failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_prim_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_prim_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_struct_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_struct_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_ref_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_ref_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_compact_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_compact_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_remap_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_remap_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
|
|
done:
|
|
btf_dedup_free(d);
|
|
return err;
|
|
}
|
|
|
|
#define BTF_UNPROCESSED_ID ((__u32)-1)
|
|
#define BTF_IN_PROGRESS_ID ((__u32)-2)
|
|
|
|
struct btf_dedup {
|
|
/* .BTF section to be deduped in-place */
|
|
struct btf *btf;
|
|
/*
|
|
* Optional .BTF.ext section. When provided, any strings referenced
|
|
* from it will be taken into account when deduping strings
|
|
*/
|
|
struct btf_ext *btf_ext;
|
|
/*
|
|
* This is a map from any type's signature hash to a list of possible
|
|
* canonical representative type candidates. Hash collisions are
|
|
* ignored, so even types of various kinds can share same list of
|
|
* candidates, which is fine because we rely on subsequent
|
|
* btf_xxx_equal() checks to authoritatively verify type equality.
|
|
*/
|
|
struct hashmap *dedup_table;
|
|
/* Canonical types map */
|
|
__u32 *map;
|
|
/* Hypothetical mapping, used during type graph equivalence checks */
|
|
__u32 *hypot_map;
|
|
__u32 *hypot_list;
|
|
size_t hypot_cnt;
|
|
size_t hypot_cap;
|
|
/* Various option modifying behavior of algorithm */
|
|
struct btf_dedup_opts opts;
|
|
};
|
|
|
|
struct btf_str_ptr {
|
|
const char *str;
|
|
__u32 new_off;
|
|
bool used;
|
|
};
|
|
|
|
struct btf_str_ptrs {
|
|
struct btf_str_ptr *ptrs;
|
|
const char *data;
|
|
__u32 cnt;
|
|
__u32 cap;
|
|
};
|
|
|
|
static long hash_combine(long h, long value)
|
|
{
|
|
return h * 31 + value;
|
|
}
|
|
|
|
#define for_each_dedup_cand(d, node, hash) \
|
|
hashmap__for_each_key_entry(d->dedup_table, node, (void *)hash)
|
|
|
|
static int btf_dedup_table_add(struct btf_dedup *d, long hash, __u32 type_id)
|
|
{
|
|
return hashmap__append(d->dedup_table,
|
|
(void *)hash, (void *)(long)type_id);
|
|
}
|
|
|
|
static int btf_dedup_hypot_map_add(struct btf_dedup *d,
|
|
__u32 from_id, __u32 to_id)
|
|
{
|
|
if (d->hypot_cnt == d->hypot_cap) {
|
|
__u32 *new_list;
|
|
|
|
d->hypot_cap += max((size_t)16, d->hypot_cap / 2);
|
|
new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32));
|
|
if (!new_list)
|
|
return -ENOMEM;
|
|
d->hypot_list = new_list;
|
|
}
|
|
d->hypot_list[d->hypot_cnt++] = from_id;
|
|
d->hypot_map[from_id] = to_id;
|
|
return 0;
|
|
}
|
|
|
|
static void btf_dedup_clear_hypot_map(struct btf_dedup *d)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < d->hypot_cnt; i++)
|
|
d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID;
|
|
d->hypot_cnt = 0;
|
|
}
|
|
|
|
static void btf_dedup_free(struct btf_dedup *d)
|
|
{
|
|
hashmap__free(d->dedup_table);
|
|
d->dedup_table = NULL;
|
|
|
|
free(d->map);
|
|
d->map = NULL;
|
|
|
|
free(d->hypot_map);
|
|
d->hypot_map = NULL;
|
|
|
|
free(d->hypot_list);
|
|
d->hypot_list = NULL;
|
|
|
|
free(d);
|
|
}
|
|
|
|
static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx)
|
|
{
|
|
return (size_t)key;
|
|
}
|
|
|
|
static size_t btf_dedup_collision_hash_fn(const void *key, void *ctx)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx)
|
|
{
|
|
return k1 == k2;
|
|
}
|
|
|
|
static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
|
|
const struct btf_dedup_opts *opts)
|
|
{
|
|
struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup));
|
|
hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn;
|
|
int i, err = 0;
|
|
|
|
if (!d)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds;
|
|
/* dedup_table_size is now used only to force collisions in tests */
|
|
if (opts && opts->dedup_table_size == 1)
|
|
hash_fn = btf_dedup_collision_hash_fn;
|
|
|
|
d->btf = btf;
|
|
d->btf_ext = btf_ext;
|
|
|
|
d->dedup_table = hashmap__new(hash_fn, btf_dedup_equal_fn, NULL);
|
|
if (IS_ERR(d->dedup_table)) {
|
|
err = PTR_ERR(d->dedup_table);
|
|
d->dedup_table = NULL;
|
|
goto done;
|
|
}
|
|
|
|
d->map = malloc(sizeof(__u32) * (1 + btf->nr_types));
|
|
if (!d->map) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
/* special BTF "void" type is made canonical immediately */
|
|
d->map[0] = 0;
|
|
for (i = 1; i <= btf->nr_types; i++) {
|
|
struct btf_type *t = btf_type_by_id(d->btf, i);
|
|
|
|
/* VAR and DATASEC are never deduped and are self-canonical */
|
|
if (btf_is_var(t) || btf_is_datasec(t))
|
|
d->map[i] = i;
|
|
else
|
|
d->map[i] = BTF_UNPROCESSED_ID;
|
|
}
|
|
|
|
d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types));
|
|
if (!d->hypot_map) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
for (i = 0; i <= btf->nr_types; i++)
|
|
d->hypot_map[i] = BTF_UNPROCESSED_ID;
|
|
|
|
done:
|
|
if (err) {
|
|
btf_dedup_free(d);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
return d;
|
|
}
|
|
|
|
typedef int (*str_off_fn_t)(__u32 *str_off_ptr, void *ctx);
|
|
|
|
/*
|
|
* Iterate over all possible places in .BTF and .BTF.ext that can reference
|
|
* string and pass pointer to it to a provided callback `fn`.
|
|
*/
|
|
static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx)
|
|
{
|
|
void *line_data_cur, *line_data_end;
|
|
int i, j, r, rec_size;
|
|
struct btf_type *t;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
t = btf_type_by_id(d->btf, i);
|
|
r = fn(&t->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
|
|
switch (btf_kind(t)) {
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION: {
|
|
struct btf_member *m = btf_members(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
|
|
for (j = 0; j < vlen; j++) {
|
|
r = fn(&m->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
m++;
|
|
}
|
|
break;
|
|
}
|
|
case BTF_KIND_ENUM: {
|
|
struct btf_enum *m = btf_enum(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
|
|
for (j = 0; j < vlen; j++) {
|
|
r = fn(&m->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
m++;
|
|
}
|
|
break;
|
|
}
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
struct btf_param *m = btf_params(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
|
|
for (j = 0; j < vlen; j++) {
|
|
r = fn(&m->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
m++;
|
|
}
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!d->btf_ext)
|
|
return 0;
|
|
|
|
line_data_cur = d->btf_ext->line_info.info;
|
|
line_data_end = d->btf_ext->line_info.info + d->btf_ext->line_info.len;
|
|
rec_size = d->btf_ext->line_info.rec_size;
|
|
|
|
while (line_data_cur < line_data_end) {
|
|
struct btf_ext_info_sec *sec = line_data_cur;
|
|
struct bpf_line_info_min *line_info;
|
|
__u32 num_info = sec->num_info;
|
|
|
|
r = fn(&sec->sec_name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
|
|
line_data_cur += sizeof(struct btf_ext_info_sec);
|
|
for (i = 0; i < num_info; i++) {
|
|
line_info = line_data_cur;
|
|
r = fn(&line_info->file_name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
r = fn(&line_info->line_off, ctx);
|
|
if (r)
|
|
return r;
|
|
line_data_cur += rec_size;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int str_sort_by_content(const void *a1, const void *a2)
|
|
{
|
|
const struct btf_str_ptr *p1 = a1;
|
|
const struct btf_str_ptr *p2 = a2;
|
|
|
|
return strcmp(p1->str, p2->str);
|
|
}
|
|
|
|
static int str_sort_by_offset(const void *a1, const void *a2)
|
|
{
|
|
const struct btf_str_ptr *p1 = a1;
|
|
const struct btf_str_ptr *p2 = a2;
|
|
|
|
if (p1->str != p2->str)
|
|
return p1->str < p2->str ? -1 : 1;
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem)
|
|
{
|
|
const struct btf_str_ptr *p = pelem;
|
|
|
|
if (str_ptr != p->str)
|
|
return (const char *)str_ptr < p->str ? -1 : 1;
|
|
return 0;
|
|
}
|
|
|
|
static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx)
|
|
{
|
|
struct btf_str_ptrs *strs;
|
|
struct btf_str_ptr *s;
|
|
|
|
if (*str_off_ptr == 0)
|
|
return 0;
|
|
|
|
strs = ctx;
|
|
s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
|
|
sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
|
|
if (!s)
|
|
return -EINVAL;
|
|
s->used = true;
|
|
return 0;
|
|
}
|
|
|
|
static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx)
|
|
{
|
|
struct btf_str_ptrs *strs;
|
|
struct btf_str_ptr *s;
|
|
|
|
if (*str_off_ptr == 0)
|
|
return 0;
|
|
|
|
strs = ctx;
|
|
s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
|
|
sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
|
|
if (!s)
|
|
return -EINVAL;
|
|
*str_off_ptr = s->new_off;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Dedup string and filter out those that are not referenced from either .BTF
|
|
* or .BTF.ext (if provided) sections.
|
|
*
|
|
* This is done by building index of all strings in BTF's string section,
|
|
* then iterating over all entities that can reference strings (e.g., type
|
|
* names, struct field names, .BTF.ext line info, etc) and marking corresponding
|
|
* strings as used. After that all used strings are deduped and compacted into
|
|
* sequential blob of memory and new offsets are calculated. Then all the string
|
|
* references are iterated again and rewritten using new offsets.
|
|
*/
|
|
static int btf_dedup_strings(struct btf_dedup *d)
|
|
{
|
|
char *start = d->btf->strs_data;
|
|
char *end = start + d->btf->hdr->str_len;
|
|
char *p = start, *tmp_strs = NULL;
|
|
struct btf_str_ptrs strs = {
|
|
.cnt = 0,
|
|
.cap = 0,
|
|
.ptrs = NULL,
|
|
.data = start,
|
|
};
|
|
int i, j, err = 0, grp_idx;
|
|
bool grp_used;
|
|
|
|
if (d->btf->strs_deduped)
|
|
return 0;
|
|
|
|
/* build index of all strings */
|
|
while (p < end) {
|
|
if (strs.cnt + 1 > strs.cap) {
|
|
struct btf_str_ptr *new_ptrs;
|
|
|
|
strs.cap += max(strs.cnt / 2, 16U);
|
|
new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0]));
|
|
if (!new_ptrs) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
strs.ptrs = new_ptrs;
|
|
}
|
|
|
|
strs.ptrs[strs.cnt].str = p;
|
|
strs.ptrs[strs.cnt].used = false;
|
|
|
|
p += strlen(p) + 1;
|
|
strs.cnt++;
|
|
}
|
|
|
|
/* temporary storage for deduplicated strings */
|
|
tmp_strs = malloc(d->btf->hdr->str_len);
|
|
if (!tmp_strs) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
|
|
/* mark all used strings */
|
|
strs.ptrs[0].used = true;
|
|
err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs);
|
|
if (err)
|
|
goto done;
|
|
|
|
/* sort strings by context, so that we can identify duplicates */
|
|
qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content);
|
|
|
|
/*
|
|
* iterate groups of equal strings and if any instance in a group was
|
|
* referenced, emit single instance and remember new offset
|
|
*/
|
|
p = tmp_strs;
|
|
grp_idx = 0;
|
|
grp_used = strs.ptrs[0].used;
|
|
/* iterate past end to avoid code duplication after loop */
|
|
for (i = 1; i <= strs.cnt; i++) {
|
|
/*
|
|
* when i == strs.cnt, we want to skip string comparison and go
|
|
* straight to handling last group of strings (otherwise we'd
|
|
* need to handle last group after the loop w/ duplicated code)
|
|
*/
|
|
if (i < strs.cnt &&
|
|
!strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) {
|
|
grp_used = grp_used || strs.ptrs[i].used;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* this check would have been required after the loop to handle
|
|
* last group of strings, but due to <= condition in a loop
|
|
* we avoid that duplication
|
|
*/
|
|
if (grp_used) {
|
|
int new_off = p - tmp_strs;
|
|
__u32 len = strlen(strs.ptrs[grp_idx].str);
|
|
|
|
memmove(p, strs.ptrs[grp_idx].str, len + 1);
|
|
for (j = grp_idx; j < i; j++)
|
|
strs.ptrs[j].new_off = new_off;
|
|
p += len + 1;
|
|
}
|
|
|
|
if (i < strs.cnt) {
|
|
grp_idx = i;
|
|
grp_used = strs.ptrs[i].used;
|
|
}
|
|
}
|
|
|
|
/* replace original strings with deduped ones */
|
|
d->btf->hdr->str_len = p - tmp_strs;
|
|
memmove(start, tmp_strs, d->btf->hdr->str_len);
|
|
end = start + d->btf->hdr->str_len;
|
|
|
|
/* restore original order for further binary search lookups */
|
|
qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset);
|
|
|
|
/* remap string offsets */
|
|
err = btf_for_each_str_off(d, btf_str_remap_offset, &strs);
|
|
if (err)
|
|
goto done;
|
|
|
|
d->btf->hdr->str_len = end - start;
|
|
d->btf->strs_deduped = true;
|
|
|
|
done:
|
|
free(tmp_strs);
|
|
free(strs.ptrs);
|
|
return err;
|
|
}
|
|
|
|
static long btf_hash_common(struct btf_type *t)
|
|
{
|
|
long h;
|
|
|
|
h = hash_combine(0, t->name_off);
|
|
h = hash_combine(h, t->info);
|
|
h = hash_combine(h, t->size);
|
|
return h;
|
|
}
|
|
|
|
static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
return t1->name_off == t2->name_off &&
|
|
t1->info == t2->info &&
|
|
t1->size == t2->size;
|
|
}
|
|
|
|
/* Calculate type signature hash of INT. */
|
|
static long btf_hash_int(struct btf_type *t)
|
|
{
|
|
__u32 info = *(__u32 *)(t + 1);
|
|
long h;
|
|
|
|
h = btf_hash_common(t);
|
|
h = hash_combine(h, info);
|
|
return h;
|
|
}
|
|
|
|
/* Check structural equality of two INTs. */
|
|
static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
__u32 info1, info2;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
info1 = *(__u32 *)(t1 + 1);
|
|
info2 = *(__u32 *)(t2 + 1);
|
|
return info1 == info2;
|
|
}
|
|
|
|
/* Calculate type signature hash of ENUM. */
|
|
static long btf_hash_enum(struct btf_type *t)
|
|
{
|
|
long h;
|
|
|
|
/* don't hash vlen and enum members to support enum fwd resolving */
|
|
h = hash_combine(0, t->name_off);
|
|
h = hash_combine(h, t->info & ~0xffff);
|
|
h = hash_combine(h, t->size);
|
|
return h;
|
|
}
|
|
|
|
/* Check structural equality of two ENUMs. */
|
|
static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
const struct btf_enum *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
vlen = btf_vlen(t1);
|
|
m1 = btf_enum(t1);
|
|
m2 = btf_enum(t2);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off || m1->val != m2->val)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static inline bool btf_is_enum_fwd(struct btf_type *t)
|
|
{
|
|
return btf_is_enum(t) && btf_vlen(t) == 0;
|
|
}
|
|
|
|
static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
|
|
return btf_equal_enum(t1, t2);
|
|
/* ignore vlen when comparing */
|
|
return t1->name_off == t2->name_off &&
|
|
(t1->info & ~0xffff) == (t2->info & ~0xffff) &&
|
|
t1->size == t2->size;
|
|
}
|
|
|
|
/*
|
|
* Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs,
|
|
* as referenced type IDs equivalence is established separately during type
|
|
* graph equivalence check algorithm.
|
|
*/
|
|
static long btf_hash_struct(struct btf_type *t)
|
|
{
|
|
const struct btf_member *member = btf_members(t);
|
|
__u32 vlen = btf_vlen(t);
|
|
long h = btf_hash_common(t);
|
|
int i;
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
h = hash_combine(h, member->name_off);
|
|
h = hash_combine(h, member->offset);
|
|
/* no hashing of referenced type ID, it can be unresolved yet */
|
|
member++;
|
|
}
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
|
|
* IDs. This check is performed during type graph equivalence check and
|
|
* referenced types equivalence is checked separately.
|
|
*/
|
|
static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
const struct btf_member *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
vlen = btf_vlen(t1);
|
|
m1 = btf_members(t1);
|
|
m2 = btf_members(t2);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off || m1->offset != m2->offset)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Calculate type signature hash of ARRAY, including referenced type IDs,
|
|
* under assumption that they were already resolved to canonical type IDs and
|
|
* are not going to change.
|
|
*/
|
|
static long btf_hash_array(struct btf_type *t)
|
|
{
|
|
const struct btf_array *info = btf_array(t);
|
|
long h = btf_hash_common(t);
|
|
|
|
h = hash_combine(h, info->type);
|
|
h = hash_combine(h, info->index_type);
|
|
h = hash_combine(h, info->nelems);
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* Check exact equality of two ARRAYs, taking into account referenced
|
|
* type IDs, under assumption that they were already resolved to canonical
|
|
* type IDs and are not going to change.
|
|
* This function is called during reference types deduplication to compare
|
|
* ARRAY to potential canonical representative.
|
|
*/
|
|
static bool btf_equal_array(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
const struct btf_array *info1, *info2;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
info1 = btf_array(t1);
|
|
info2 = btf_array(t2);
|
|
return info1->type == info2->type &&
|
|
info1->index_type == info2->index_type &&
|
|
info1->nelems == info2->nelems;
|
|
}
|
|
|
|
/*
|
|
* Check structural compatibility of two ARRAYs, ignoring referenced type
|
|
* IDs. This check is performed during type graph equivalence check and
|
|
* referenced types equivalence is checked separately.
|
|
*/
|
|
static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
return btf_array(t1)->nelems == btf_array(t2)->nelems;
|
|
}
|
|
|
|
/*
|
|
* Calculate type signature hash of FUNC_PROTO, including referenced type IDs,
|
|
* under assumption that they were already resolved to canonical type IDs and
|
|
* are not going to change.
|
|
*/
|
|
static long btf_hash_fnproto(struct btf_type *t)
|
|
{
|
|
const struct btf_param *member = btf_params(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
long h = btf_hash_common(t);
|
|
int i;
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
h = hash_combine(h, member->name_off);
|
|
h = hash_combine(h, member->type);
|
|
member++;
|
|
}
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* Check exact equality of two FUNC_PROTOs, taking into account referenced
|
|
* type IDs, under assumption that they were already resolved to canonical
|
|
* type IDs and are not going to change.
|
|
* This function is called during reference types deduplication to compare
|
|
* FUNC_PROTO to potential canonical representative.
|
|
*/
|
|
static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
const struct btf_param *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
vlen = btf_vlen(t1);
|
|
m1 = btf_params(t1);
|
|
m2 = btf_params(t2);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off || m1->type != m2->type)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
|
|
* IDs. This check is performed during type graph equivalence check and
|
|
* referenced types equivalence is checked separately.
|
|
*/
|
|
static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
const struct btf_param *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
/* skip return type ID */
|
|
if (t1->name_off != t2->name_off || t1->info != t2->info)
|
|
return false;
|
|
|
|
vlen = btf_vlen(t1);
|
|
m1 = btf_params(t1);
|
|
m2 = btf_params(t2);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Deduplicate primitive types, that can't reference other types, by calculating
|
|
* their type signature hash and comparing them with any possible canonical
|
|
* candidate. If no canonical candidate matches, type itself is marked as
|
|
* canonical and is added into `btf_dedup->dedup_table` as another candidate.
|
|
*/
|
|
static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct btf_type *t = btf_type_by_id(d->btf, type_id);
|
|
struct hashmap_entry *hash_entry;
|
|
struct btf_type *cand;
|
|
/* if we don't find equivalent type, then we are canonical */
|
|
__u32 new_id = type_id;
|
|
__u32 cand_id;
|
|
long h;
|
|
|
|
switch (btf_kind(t)) {
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_TYPEDEF:
|
|
case BTF_KIND_ARRAY:
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION:
|
|
case BTF_KIND_FUNC:
|
|
case BTF_KIND_FUNC_PROTO:
|
|
case BTF_KIND_VAR:
|
|
case BTF_KIND_DATASEC:
|
|
return 0;
|
|
|
|
case BTF_KIND_INT:
|
|
h = btf_hash_int(t);
|
|
for_each_dedup_cand(d, hash_entry, h) {
|
|
cand_id = (__u32)(long)hash_entry->value;
|
|
cand = btf_type_by_id(d->btf, cand_id);
|
|
if (btf_equal_int(t, cand)) {
|
|
new_id = cand_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case BTF_KIND_ENUM:
|
|
h = btf_hash_enum(t);
|
|
for_each_dedup_cand(d, hash_entry, h) {
|
|
cand_id = (__u32)(long)hash_entry->value;
|
|
cand = btf_type_by_id(d->btf, cand_id);
|
|
if (btf_equal_enum(t, cand)) {
|
|
new_id = cand_id;
|
|
break;
|
|
}
|
|
if (d->opts.dont_resolve_fwds)
|
|
continue;
|
|
if (btf_compat_enum(t, cand)) {
|
|
if (btf_is_enum_fwd(t)) {
|
|
/* resolve fwd to full enum */
|
|
new_id = cand_id;
|
|
break;
|
|
}
|
|
/* resolve canonical enum fwd to full enum */
|
|
d->map[cand_id] = type_id;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case BTF_KIND_FWD:
|
|
h = btf_hash_common(t);
|
|
for_each_dedup_cand(d, hash_entry, h) {
|
|
cand_id = (__u32)(long)hash_entry->value;
|
|
cand = btf_type_by_id(d->btf, cand_id);
|
|
if (btf_equal_common(t, cand)) {
|
|
new_id = cand_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
d->map[type_id] = new_id;
|
|
if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_prim_types(struct btf_dedup *d)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
err = btf_dedup_prim_type(d, i);
|
|
if (err)
|
|
return err;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Check whether type is already mapped into canonical one (could be to itself).
|
|
*/
|
|
static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id)
|
|
{
|
|
return d->map[type_id] <= BTF_MAX_NR_TYPES;
|
|
}
|
|
|
|
/*
|
|
* Resolve type ID into its canonical type ID, if any; otherwise return original
|
|
* type ID. If type is FWD and is resolved into STRUCT/UNION already, follow
|
|
* STRUCT/UNION link and resolve it into canonical type ID as well.
|
|
*/
|
|
static inline __u32 resolve_type_id(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
|
|
type_id = d->map[type_id];
|
|
return type_id;
|
|
}
|
|
|
|
/*
|
|
* Resolve FWD to underlying STRUCT/UNION, if any; otherwise return original
|
|
* type ID.
|
|
*/
|
|
static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id)
|
|
{
|
|
__u32 orig_type_id = type_id;
|
|
|
|
if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
|
|
return type_id;
|
|
|
|
while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
|
|
type_id = d->map[type_id];
|
|
|
|
if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
|
|
return type_id;
|
|
|
|
return orig_type_id;
|
|
}
|
|
|
|
|
|
static inline __u16 btf_fwd_kind(struct btf_type *t)
|
|
{
|
|
return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT;
|
|
}
|
|
|
|
/*
|
|
* Check equivalence of BTF type graph formed by candidate struct/union (we'll
|
|
* call it "candidate graph" in this description for brevity) to a type graph
|
|
* formed by (potential) canonical struct/union ("canonical graph" for brevity
|
|
* here, though keep in mind that not all types in canonical graph are
|
|
* necessarily canonical representatives themselves, some of them might be
|
|
* duplicates or its uniqueness might not have been established yet).
|
|
* Returns:
|
|
* - >0, if type graphs are equivalent;
|
|
* - 0, if not equivalent;
|
|
* - <0, on error.
|
|
*
|
|
* Algorithm performs side-by-side DFS traversal of both type graphs and checks
|
|
* equivalence of BTF types at each step. If at any point BTF types in candidate
|
|
* and canonical graphs are not compatible structurally, whole graphs are
|
|
* incompatible. If types are structurally equivalent (i.e., all information
|
|
* except referenced type IDs is exactly the same), a mapping from `canon_id` to
|
|
* a `cand_id` is recored in hypothetical mapping (`btf_dedup->hypot_map`).
|
|
* If a type references other types, then those referenced types are checked
|
|
* for equivalence recursively.
|
|
*
|
|
* During DFS traversal, if we find that for current `canon_id` type we
|
|
* already have some mapping in hypothetical map, we check for two possible
|
|
* situations:
|
|
* - `canon_id` is mapped to exactly the same type as `cand_id`. This will
|
|
* happen when type graphs have cycles. In this case we assume those two
|
|
* types are equivalent.
|
|
* - `canon_id` is mapped to different type. This is contradiction in our
|
|
* hypothetical mapping, because same graph in canonical graph corresponds
|
|
* to two different types in candidate graph, which for equivalent type
|
|
* graphs shouldn't happen. This condition terminates equivalence check
|
|
* with negative result.
|
|
*
|
|
* If type graphs traversal exhausts types to check and find no contradiction,
|
|
* then type graphs are equivalent.
|
|
*
|
|
* When checking types for equivalence, there is one special case: FWD types.
|
|
* If FWD type resolution is allowed and one of the types (either from canonical
|
|
* or candidate graph) is FWD and other is STRUCT/UNION (depending on FWD's kind
|
|
* flag) and their names match, hypothetical mapping is updated to point from
|
|
* FWD to STRUCT/UNION. If graphs will be determined as equivalent successfully,
|
|
* this mapping will be used to record FWD -> STRUCT/UNION mapping permanently.
|
|
*
|
|
* Technically, this could lead to incorrect FWD to STRUCT/UNION resolution,
|
|
* if there are two exactly named (or anonymous) structs/unions that are
|
|
* compatible structurally, one of which has FWD field, while other is concrete
|
|
* STRUCT/UNION, but according to C sources they are different structs/unions
|
|
* that are referencing different types with the same name. This is extremely
|
|
* unlikely to happen, but btf_dedup API allows to disable FWD resolution if
|
|
* this logic is causing problems.
|
|
*
|
|
* Doing FWD resolution means that both candidate and/or canonical graphs can
|
|
* consists of portions of the graph that come from multiple compilation units.
|
|
* This is due to the fact that types within single compilation unit are always
|
|
* deduplicated and FWDs are already resolved, if referenced struct/union
|
|
* definiton is available. So, if we had unresolved FWD and found corresponding
|
|
* STRUCT/UNION, they will be from different compilation units. This
|
|
* consequently means that when we "link" FWD to corresponding STRUCT/UNION,
|
|
* type graph will likely have at least two different BTF types that describe
|
|
* same type (e.g., most probably there will be two different BTF types for the
|
|
* same 'int' primitive type) and could even have "overlapping" parts of type
|
|
* graph that describe same subset of types.
|
|
*
|
|
* This in turn means that our assumption that each type in canonical graph
|
|
* must correspond to exactly one type in candidate graph might not hold
|
|
* anymore and will make it harder to detect contradictions using hypothetical
|
|
* map. To handle this problem, we allow to follow FWD -> STRUCT/UNION
|
|
* resolution only in canonical graph. FWDs in candidate graphs are never
|
|
* resolved. To see why it's OK, let's check all possible situations w.r.t. FWDs
|
|
* that can occur:
|
|
* - Both types in canonical and candidate graphs are FWDs. If they are
|
|
* structurally equivalent, then they can either be both resolved to the
|
|
* same STRUCT/UNION or not resolved at all. In both cases they are
|
|
* equivalent and there is no need to resolve FWD on candidate side.
|
|
* - Both types in canonical and candidate graphs are concrete STRUCT/UNION,
|
|
* so nothing to resolve as well, algorithm will check equivalence anyway.
|
|
* - Type in canonical graph is FWD, while type in candidate is concrete
|
|
* STRUCT/UNION. In this case candidate graph comes from single compilation
|
|
* unit, so there is exactly one BTF type for each unique C type. After
|
|
* resolving FWD into STRUCT/UNION, there might be more than one BTF type
|
|
* in canonical graph mapping to single BTF type in candidate graph, but
|
|
* because hypothetical mapping maps from canonical to candidate types, it's
|
|
* alright, and we still maintain the property of having single `canon_id`
|
|
* mapping to single `cand_id` (there could be two different `canon_id`
|
|
* mapped to the same `cand_id`, but it's not contradictory).
|
|
* - Type in canonical graph is concrete STRUCT/UNION, while type in candidate
|
|
* graph is FWD. In this case we are just going to check compatibility of
|
|
* STRUCT/UNION and corresponding FWD, and if they are compatible, we'll
|
|
* assume that whatever STRUCT/UNION FWD resolves to must be equivalent to
|
|
* a concrete STRUCT/UNION from canonical graph. If the rest of type graphs
|
|
* turn out equivalent, we'll re-resolve FWD to concrete STRUCT/UNION from
|
|
* canonical graph.
|
|
*/
|
|
static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
|
|
__u32 canon_id)
|
|
{
|
|
struct btf_type *cand_type;
|
|
struct btf_type *canon_type;
|
|
__u32 hypot_type_id;
|
|
__u16 cand_kind;
|
|
__u16 canon_kind;
|
|
int i, eq;
|
|
|
|
/* if both resolve to the same canonical, they must be equivalent */
|
|
if (resolve_type_id(d, cand_id) == resolve_type_id(d, canon_id))
|
|
return 1;
|
|
|
|
canon_id = resolve_fwd_id(d, canon_id);
|
|
|
|
hypot_type_id = d->hypot_map[canon_id];
|
|
if (hypot_type_id <= BTF_MAX_NR_TYPES)
|
|
return hypot_type_id == cand_id;
|
|
|
|
if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
|
|
return -ENOMEM;
|
|
|
|
cand_type = btf_type_by_id(d->btf, cand_id);
|
|
canon_type = btf_type_by_id(d->btf, canon_id);
|
|
cand_kind = btf_kind(cand_type);
|
|
canon_kind = btf_kind(canon_type);
|
|
|
|
if (cand_type->name_off != canon_type->name_off)
|
|
return 0;
|
|
|
|
/* FWD <--> STRUCT/UNION equivalence check, if enabled */
|
|
if (!d->opts.dont_resolve_fwds
|
|
&& (cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD)
|
|
&& cand_kind != canon_kind) {
|
|
__u16 real_kind;
|
|
__u16 fwd_kind;
|
|
|
|
if (cand_kind == BTF_KIND_FWD) {
|
|
real_kind = canon_kind;
|
|
fwd_kind = btf_fwd_kind(cand_type);
|
|
} else {
|
|
real_kind = cand_kind;
|
|
fwd_kind = btf_fwd_kind(canon_type);
|
|
}
|
|
return fwd_kind == real_kind;
|
|
}
|
|
|
|
if (cand_kind != canon_kind)
|
|
return 0;
|
|
|
|
switch (cand_kind) {
|
|
case BTF_KIND_INT:
|
|
return btf_equal_int(cand_type, canon_type);
|
|
|
|
case BTF_KIND_ENUM:
|
|
if (d->opts.dont_resolve_fwds)
|
|
return btf_equal_enum(cand_type, canon_type);
|
|
else
|
|
return btf_compat_enum(cand_type, canon_type);
|
|
|
|
case BTF_KIND_FWD:
|
|
return btf_equal_common(cand_type, canon_type);
|
|
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_TYPEDEF:
|
|
case BTF_KIND_FUNC:
|
|
if (cand_type->info != canon_type->info)
|
|
return 0;
|
|
return btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
|
|
|
|
case BTF_KIND_ARRAY: {
|
|
const struct btf_array *cand_arr, *canon_arr;
|
|
|
|
if (!btf_compat_array(cand_type, canon_type))
|
|
return 0;
|
|
cand_arr = btf_array(cand_type);
|
|
canon_arr = btf_array(canon_type);
|
|
eq = btf_dedup_is_equiv(d,
|
|
cand_arr->index_type, canon_arr->index_type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type);
|
|
}
|
|
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION: {
|
|
const struct btf_member *cand_m, *canon_m;
|
|
__u16 vlen;
|
|
|
|
if (!btf_shallow_equal_struct(cand_type, canon_type))
|
|
return 0;
|
|
vlen = btf_vlen(cand_type);
|
|
cand_m = btf_members(cand_type);
|
|
canon_m = btf_members(canon_type);
|
|
for (i = 0; i < vlen; i++) {
|
|
eq = btf_dedup_is_equiv(d, cand_m->type, canon_m->type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
cand_m++;
|
|
canon_m++;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
const struct btf_param *cand_p, *canon_p;
|
|
__u16 vlen;
|
|
|
|
if (!btf_compat_fnproto(cand_type, canon_type))
|
|
return 0;
|
|
eq = btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
vlen = btf_vlen(cand_type);
|
|
cand_p = btf_params(cand_type);
|
|
canon_p = btf_params(canon_type);
|
|
for (i = 0; i < vlen; i++) {
|
|
eq = btf_dedup_is_equiv(d, cand_p->type, canon_p->type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
cand_p++;
|
|
canon_p++;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Use hypothetical mapping, produced by successful type graph equivalence
|
|
* check, to augment existing struct/union canonical mapping, where possible.
|
|
*
|
|
* If BTF_KIND_FWD resolution is allowed, this mapping is also used to record
|
|
* FWD -> STRUCT/UNION correspondence as well. FWD resolution is bidirectional:
|
|
* it doesn't matter if FWD type was part of canonical graph or candidate one,
|
|
* we are recording the mapping anyway. As opposed to carefulness required
|
|
* for struct/union correspondence mapping (described below), for FWD resolution
|
|
* it's not important, as by the time that FWD type (reference type) will be
|
|
* deduplicated all structs/unions will be deduped already anyway.
|
|
*
|
|
* Recording STRUCT/UNION mapping is purely a performance optimization and is
|
|
* not required for correctness. It needs to be done carefully to ensure that
|
|
* struct/union from candidate's type graph is not mapped into corresponding
|
|
* struct/union from canonical type graph that itself hasn't been resolved into
|
|
* canonical representative. The only guarantee we have is that canonical
|
|
* struct/union was determined as canonical and that won't change. But any
|
|
* types referenced through that struct/union fields could have been not yet
|
|
* resolved, so in case like that it's too early to establish any kind of
|
|
* correspondence between structs/unions.
|
|
*
|
|
* No canonical correspondence is derived for primitive types (they are already
|
|
* deduplicated completely already anyway) or reference types (they rely on
|
|
* stability of struct/union canonical relationship for equivalence checks).
|
|
*/
|
|
static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
|
|
{
|
|
__u32 cand_type_id, targ_type_id;
|
|
__u16 t_kind, c_kind;
|
|
__u32 t_id, c_id;
|
|
int i;
|
|
|
|
for (i = 0; i < d->hypot_cnt; i++) {
|
|
cand_type_id = d->hypot_list[i];
|
|
targ_type_id = d->hypot_map[cand_type_id];
|
|
t_id = resolve_type_id(d, targ_type_id);
|
|
c_id = resolve_type_id(d, cand_type_id);
|
|
t_kind = btf_kind(btf__type_by_id(d->btf, t_id));
|
|
c_kind = btf_kind(btf__type_by_id(d->btf, c_id));
|
|
/*
|
|
* Resolve FWD into STRUCT/UNION.
|
|
* It's ok to resolve FWD into STRUCT/UNION that's not yet
|
|
* mapped to canonical representative (as opposed to
|
|
* STRUCT/UNION <--> STRUCT/UNION mapping logic below), because
|
|
* eventually that struct is going to be mapped and all resolved
|
|
* FWDs will automatically resolve to correct canonical
|
|
* representative. This will happen before ref type deduping,
|
|
* which critically depends on stability of these mapping. This
|
|
* stability is not a requirement for STRUCT/UNION equivalence
|
|
* checks, though.
|
|
*/
|
|
if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD)
|
|
d->map[c_id] = t_id;
|
|
else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
|
|
d->map[t_id] = c_id;
|
|
|
|
if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) &&
|
|
c_kind != BTF_KIND_FWD &&
|
|
is_type_mapped(d, c_id) &&
|
|
!is_type_mapped(d, t_id)) {
|
|
/*
|
|
* as a perf optimization, we can map struct/union
|
|
* that's part of type graph we just verified for
|
|
* equivalence. We can do that for struct/union that has
|
|
* canonical representative only, though.
|
|
*/
|
|
d->map[t_id] = c_id;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deduplicate struct/union types.
|
|
*
|
|
* For each struct/union type its type signature hash is calculated, taking
|
|
* into account type's name, size, number, order and names of fields, but
|
|
* ignoring type ID's referenced from fields, because they might not be deduped
|
|
* completely until after reference types deduplication phase. This type hash
|
|
* is used to iterate over all potential canonical types, sharing same hash.
|
|
* For each canonical candidate we check whether type graphs that they form
|
|
* (through referenced types in fields and so on) are equivalent using algorithm
|
|
* implemented in `btf_dedup_is_equiv`. If such equivalence is found and
|
|
* BTF_KIND_FWD resolution is allowed, then hypothetical mapping
|
|
* (btf_dedup->hypot_map) produced by aforementioned type graph equivalence
|
|
* algorithm is used to record FWD -> STRUCT/UNION mapping. It's also used to
|
|
* potentially map other structs/unions to their canonical representatives,
|
|
* if such relationship hasn't yet been established. This speeds up algorithm
|
|
* by eliminating some of the duplicate work.
|
|
*
|
|
* If no matching canonical representative was found, struct/union is marked
|
|
* as canonical for itself and is added into btf_dedup->dedup_table hash map
|
|
* for further look ups.
|
|
*/
|
|
static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct btf_type *cand_type, *t;
|
|
struct hashmap_entry *hash_entry;
|
|
/* if we don't find equivalent type, then we are canonical */
|
|
__u32 new_id = type_id;
|
|
__u16 kind;
|
|
long h;
|
|
|
|
/* already deduped or is in process of deduping (loop detected) */
|
|
if (d->map[type_id] <= BTF_MAX_NR_TYPES)
|
|
return 0;
|
|
|
|
t = btf_type_by_id(d->btf, type_id);
|
|
kind = btf_kind(t);
|
|
|
|
if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION)
|
|
return 0;
|
|
|
|
h = btf_hash_struct(t);
|
|
for_each_dedup_cand(d, hash_entry, h) {
|
|
__u32 cand_id = (__u32)(long)hash_entry->value;
|
|
int eq;
|
|
|
|
/*
|
|
* Even though btf_dedup_is_equiv() checks for
|
|
* btf_shallow_equal_struct() internally when checking two
|
|
* structs (unions) for equivalence, we need to guard here
|
|
* from picking matching FWD type as a dedup candidate.
|
|
* This can happen due to hash collision. In such case just
|
|
* relying on btf_dedup_is_equiv() would lead to potentially
|
|
* creating a loop (FWD -> STRUCT and STRUCT -> FWD), because
|
|
* FWD and compatible STRUCT/UNION are considered equivalent.
|
|
*/
|
|
cand_type = btf_type_by_id(d->btf, cand_id);
|
|
if (!btf_shallow_equal_struct(t, cand_type))
|
|
continue;
|
|
|
|
btf_dedup_clear_hypot_map(d);
|
|
eq = btf_dedup_is_equiv(d, type_id, cand_id);
|
|
if (eq < 0)
|
|
return eq;
|
|
if (!eq)
|
|
continue;
|
|
new_id = cand_id;
|
|
btf_dedup_merge_hypot_map(d);
|
|
break;
|
|
}
|
|
|
|
d->map[type_id] = new_id;
|
|
if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_struct_types(struct btf_dedup *d)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
err = btf_dedup_struct_type(d, i);
|
|
if (err)
|
|
return err;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Deduplicate reference type.
|
|
*
|
|
* Once all primitive and struct/union types got deduplicated, we can easily
|
|
* deduplicate all other (reference) BTF types. This is done in two steps:
|
|
*
|
|
* 1. Resolve all referenced type IDs into their canonical type IDs. This
|
|
* resolution can be done either immediately for primitive or struct/union types
|
|
* (because they were deduped in previous two phases) or recursively for
|
|
* reference types. Recursion will always terminate at either primitive or
|
|
* struct/union type, at which point we can "unwind" chain of reference types
|
|
* one by one. There is no danger of encountering cycles because in C type
|
|
* system the only way to form type cycle is through struct/union, so any chain
|
|
* of reference types, even those taking part in a type cycle, will inevitably
|
|
* reach struct/union at some point.
|
|
*
|
|
* 2. Once all referenced type IDs are resolved into canonical ones, BTF type
|
|
* becomes "stable", in the sense that no further deduplication will cause
|
|
* any changes to it. With that, it's now possible to calculate type's signature
|
|
* hash (this time taking into account referenced type IDs) and loop over all
|
|
* potential canonical representatives. If no match was found, current type
|
|
* will become canonical representative of itself and will be added into
|
|
* btf_dedup->dedup_table as another possible canonical representative.
|
|
*/
|
|
static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct hashmap_entry *hash_entry;
|
|
__u32 new_id = type_id, cand_id;
|
|
struct btf_type *t, *cand;
|
|
/* if we don't find equivalent type, then we are representative type */
|
|
int ref_type_id;
|
|
long h;
|
|
|
|
if (d->map[type_id] == BTF_IN_PROGRESS_ID)
|
|
return -ELOOP;
|
|
if (d->map[type_id] <= BTF_MAX_NR_TYPES)
|
|
return resolve_type_id(d, type_id);
|
|
|
|
t = btf_type_by_id(d->btf, type_id);
|
|
d->map[type_id] = BTF_IN_PROGRESS_ID;
|
|
|
|
switch (btf_kind(t)) {
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_TYPEDEF:
|
|
case BTF_KIND_FUNC:
|
|
ref_type_id = btf_dedup_ref_type(d, t->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
t->type = ref_type_id;
|
|
|
|
h = btf_hash_common(t);
|
|
for_each_dedup_cand(d, hash_entry, h) {
|
|
cand_id = (__u32)(long)hash_entry->value;
|
|
cand = btf_type_by_id(d->btf, cand_id);
|
|
if (btf_equal_common(t, cand)) {
|
|
new_id = cand_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case BTF_KIND_ARRAY: {
|
|
struct btf_array *info = btf_array(t);
|
|
|
|
ref_type_id = btf_dedup_ref_type(d, info->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
info->type = ref_type_id;
|
|
|
|
ref_type_id = btf_dedup_ref_type(d, info->index_type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
info->index_type = ref_type_id;
|
|
|
|
h = btf_hash_array(t);
|
|
for_each_dedup_cand(d, hash_entry, h) {
|
|
cand_id = (__u32)(long)hash_entry->value;
|
|
cand = btf_type_by_id(d->btf, cand_id);
|
|
if (btf_equal_array(t, cand)) {
|
|
new_id = cand_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
struct btf_param *param;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
ref_type_id = btf_dedup_ref_type(d, t->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
t->type = ref_type_id;
|
|
|
|
vlen = btf_vlen(t);
|
|
param = btf_params(t);
|
|
for (i = 0; i < vlen; i++) {
|
|
ref_type_id = btf_dedup_ref_type(d, param->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
param->type = ref_type_id;
|
|
param++;
|
|
}
|
|
|
|
h = btf_hash_fnproto(t);
|
|
for_each_dedup_cand(d, hash_entry, h) {
|
|
cand_id = (__u32)(long)hash_entry->value;
|
|
cand = btf_type_by_id(d->btf, cand_id);
|
|
if (btf_equal_fnproto(t, cand)) {
|
|
new_id = cand_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
d->map[type_id] = new_id;
|
|
if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
|
|
return -ENOMEM;
|
|
|
|
return new_id;
|
|
}
|
|
|
|
static int btf_dedup_ref_types(struct btf_dedup *d)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
err = btf_dedup_ref_type(d, i);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
/* we won't need d->dedup_table anymore */
|
|
hashmap__free(d->dedup_table);
|
|
d->dedup_table = NULL;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Compact types.
|
|
*
|
|
* After we established for each type its corresponding canonical representative
|
|
* type, we now can eliminate types that are not canonical and leave only
|
|
* canonical ones layed out sequentially in memory by copying them over
|
|
* duplicates. During compaction btf_dedup->hypot_map array is reused to store
|
|
* a map from original type ID to a new compacted type ID, which will be used
|
|
* during next phase to "fix up" type IDs, referenced from struct/union and
|
|
* reference types.
|
|
*/
|
|
static int btf_dedup_compact_types(struct btf_dedup *d)
|
|
{
|
|
__u32 *new_offs;
|
|
__u32 next_type_id = 1;
|
|
void *p;
|
|
int i, len;
|
|
|
|
/* we are going to reuse hypot_map to store compaction remapping */
|
|
d->hypot_map[0] = 0;
|
|
for (i = 1; i <= d->btf->nr_types; i++)
|
|
d->hypot_map[i] = BTF_UNPROCESSED_ID;
|
|
|
|
p = d->btf->types_data;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
if (d->map[i] != i)
|
|
continue;
|
|
|
|
len = btf_type_size(btf__type_by_id(d->btf, i));
|
|
if (len < 0)
|
|
return len;
|
|
|
|
memmove(p, btf__type_by_id(d->btf, i), len);
|
|
d->hypot_map[i] = next_type_id;
|
|
d->btf->type_offs[next_type_id] = p - d->btf->types_data;
|
|
p += len;
|
|
next_type_id++;
|
|
}
|
|
|
|
/* shrink struct btf's internal types index and update btf_header */
|
|
d->btf->nr_types = next_type_id - 1;
|
|
d->btf->type_offs_cap = d->btf->nr_types + 1;
|
|
d->btf->hdr->type_len = p - d->btf->types_data;
|
|
new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap,
|
|
sizeof(*new_offs));
|
|
if (!new_offs)
|
|
return -ENOMEM;
|
|
d->btf->type_offs = new_offs;
|
|
d->btf->hdr->str_off = d->btf->hdr->type_len;
|
|
d->btf->raw_size = d->btf->hdr->hdr_len + d->btf->hdr->type_len + d->btf->hdr->str_len;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Figure out final (deduplicated and compacted) type ID for provided original
|
|
* `type_id` by first resolving it into corresponding canonical type ID and
|
|
* then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map,
|
|
* which is populated during compaction phase.
|
|
*/
|
|
static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
__u32 resolved_type_id, new_type_id;
|
|
|
|
resolved_type_id = resolve_type_id(d, type_id);
|
|
new_type_id = d->hypot_map[resolved_type_id];
|
|
if (new_type_id > BTF_MAX_NR_TYPES)
|
|
return -EINVAL;
|
|
return new_type_id;
|
|
}
|
|
|
|
/*
|
|
* Remap referenced type IDs into deduped type IDs.
|
|
*
|
|
* After BTF types are deduplicated and compacted, their final type IDs may
|
|
* differ from original ones. The map from original to a corresponding
|
|
* deduped type ID is stored in btf_dedup->hypot_map and is populated during
|
|
* compaction phase. During remapping phase we are rewriting all type IDs
|
|
* referenced from any BTF type (e.g., struct fields, func proto args, etc) to
|
|
* their final deduped type IDs.
|
|
*/
|
|
static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct btf_type *t = btf_type_by_id(d->btf, type_id);
|
|
int i, r;
|
|
|
|
switch (btf_kind(t)) {
|
|
case BTF_KIND_INT:
|
|
case BTF_KIND_ENUM:
|
|
break;
|
|
|
|
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_VAR:
|
|
r = btf_dedup_remap_type_id(d, t->type);
|
|
if (r < 0)
|
|
return r;
|
|
t->type = r;
|
|
break;
|
|
|
|
case BTF_KIND_ARRAY: {
|
|
struct btf_array *arr_info = btf_array(t);
|
|
|
|
r = btf_dedup_remap_type_id(d, arr_info->type);
|
|
if (r < 0)
|
|
return r;
|
|
arr_info->type = r;
|
|
r = btf_dedup_remap_type_id(d, arr_info->index_type);
|
|
if (r < 0)
|
|
return r;
|
|
arr_info->index_type = r;
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION: {
|
|
struct btf_member *member = btf_members(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
r = btf_dedup_remap_type_id(d, member->type);
|
|
if (r < 0)
|
|
return r;
|
|
member->type = r;
|
|
member++;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
struct btf_param *param = btf_params(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
|
|
r = btf_dedup_remap_type_id(d, t->type);
|
|
if (r < 0)
|
|
return r;
|
|
t->type = r;
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
r = btf_dedup_remap_type_id(d, param->type);
|
|
if (r < 0)
|
|
return r;
|
|
param->type = r;
|
|
param++;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_DATASEC: {
|
|
struct btf_var_secinfo *var = btf_var_secinfos(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
r = btf_dedup_remap_type_id(d, var->type);
|
|
if (r < 0)
|
|
return r;
|
|
var->type = r;
|
|
var++;
|
|
}
|
|
break;
|
|
}
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_remap_types(struct btf_dedup *d)
|
|
{
|
|
int i, r;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
r = btf_dedup_remap_type(d, i);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Probe few well-known locations for vmlinux kernel image and try to load BTF
|
|
* data out of it to use for target BTF.
|
|
*/
|
|
struct btf *libbpf_find_kernel_btf(void)
|
|
{
|
|
struct {
|
|
const char *path_fmt;
|
|
bool raw_btf;
|
|
} locations[] = {
|
|
/* try canonical vmlinux BTF through sysfs first */
|
|
{ "/sys/kernel/btf/vmlinux", true /* raw BTF */ },
|
|
/* fall back to trying to find vmlinux ELF on disk otherwise */
|
|
{ "/boot/vmlinux-%1$s" },
|
|
{ "/lib/modules/%1$s/vmlinux-%1$s" },
|
|
{ "/lib/modules/%1$s/build/vmlinux" },
|
|
{ "/usr/lib/modules/%1$s/kernel/vmlinux" },
|
|
{ "/usr/lib/debug/boot/vmlinux-%1$s" },
|
|
{ "/usr/lib/debug/boot/vmlinux-%1$s.debug" },
|
|
{ "/usr/lib/debug/lib/modules/%1$s/vmlinux" },
|
|
};
|
|
char path[PATH_MAX + 1];
|
|
struct utsname buf;
|
|
struct btf *btf;
|
|
int i;
|
|
|
|
uname(&buf);
|
|
|
|
for (i = 0; i < ARRAY_SIZE(locations); i++) {
|
|
snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release);
|
|
|
|
if (access(path, R_OK))
|
|
continue;
|
|
|
|
if (locations[i].raw_btf)
|
|
btf = btf__parse_raw(path);
|
|
else
|
|
btf = btf__parse_elf(path, NULL);
|
|
|
|
pr_debug("loading kernel BTF '%s': %ld\n",
|
|
path, IS_ERR(btf) ? PTR_ERR(btf) : 0);
|
|
if (IS_ERR(btf))
|
|
continue;
|
|
|
|
return btf;
|
|
}
|
|
|
|
pr_warn("failed to find valid kernel BTF\n");
|
|
return ERR_PTR(-ESRCH);
|
|
}
|