bpf: btf: Validate type reference

/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) 2018 Facebook */

#ifndef _LINUX_BTF_H

#define _LINUX_BTF_H 1

#include <linux/types.h>

struct btf;

struct btf_type;

/* Figure out the size of a type_id.  If type_id is a modifier

 * (e.g. const), it will be resolved to find out the type with size.

 *

 * For example:

 * In describing "const void *",  type_id is "const" and "const"

 * refers to "void *".  The return type will be "void *".

 *

 * If type_id is a simple "int", then return type will be "int".

 *

 * @btf: struct btf object

 * @type_id: Find out the size of type_id. The type_id of the return

 *           type is set to *type_id.

 * @ret_size: It can be NULL.  If not NULL, the size of the return

 *            type is set to *ret_size.

 * Return: The btf_type (resolved to another type with size info if needed).

 *         NULL is returned if type_id itself does not have size info

 *         (e.g. void) or it cannot be resolved to another type that

 *         has size info.

 *         *type_id and *ret_size will not be changed in the

 *         NULL return case.

 */

const struct btf_type *btf_type_id_size(const struct btf *btf,

					u32 *type_id,

					u32 *ret_size);

#endif