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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Helpers for defining versioned symbols
*
* Copyright (C) 2021-2025 Red Hat, Inc. All rights reserved.
*/
#ifndef _LIBCRYPTSETUP_SYMVER_H
#define _LIBCRYPTSETUP_SYMVER_H
/*
* Note on usage:
*
* Do not use CRYPT_SYMBOL_EXPORT_NEW and CRYPT_SYMBOL_EXPORT_OLD on public
* symbols being exported only once. Linker will handle it automatically as
* always.
*
* It's supposed to be used only with symbols that are exported in at least
* two versions simultaneously as follows:
*
* - the latest version is marked with _NEW variant and all other compatible
* symbols should be marked with _OLD variant
*
* Examples:
*
* - int crypt_func_X(unsigned *x, long y) gets introduced in CRYPTSETUP_2.4.
*
* No need to use any macro referenced here, just add proper version
* mapping in libcryptsetup.sym file.
*
* In later version CRYPTSETUP_2.5 symbol crypt_func_X has to fixed
* in incompatible way by adding new function parameter. The new version
* has to be added in mapping file libcryptsetup.sym as well.
*
* The definition of compatible function gets prefixed with following macro:
*
* CRYPT_SYMBOL_EXPORT_OLD(int, crypt_func_X, 2, 4,
* unsigned *x, long y)
* {
* function body
* }
*
* Whereas new version introduced in CRYPTSETUP_2.5 is defined as follows:
*
* CRYPT_SYMBOL_EXPORT_NEW(int, crypt_func_X, 2, 5,
* unsigned *x, long y, void *new_parameter)
* {
* function body
* }
*
* If in later version CRYPTSETUP_2.6 yet another version of crypt_func_X gets
* introduced it will be prefixed with CRYPT_SYMBOL_EXPORT_NEW(int, crypt_func_X, 2, 6...)
* macro and all previous versions CRYPTSETUP_2.4 and CRYPTSETUP_2.5 will be
* under CRYPT_SYMBOL_EXPORT_OLD(int, crypt_func_X, ...) macro
*/
#if HAVE_ATTRIBUTE_SYMVER
# define _CRYPT_SYMVER(_local_sym, _public_sym, _ver_str, _maj, _min) \
__attribute__((__symver__(#_public_sym _ver_str #_maj "." #_min)))
#endif
#if !defined(_CRYPT_SYMVER) && (defined(__GNUC__) || defined(__clang__))
# define _CRYPT_SYMVER(_local_sym, _public_sym, _ver_str, _maj, _min) \
__asm__(".symver " #_local_sym "," #_public_sym _ver_str #_maj "." #_min);
#endif
#define _CRYPT_FUNC(_public_sym, _prefix_str, _maj, _min, _ret, ...) \
_ret __##_public_sym##_v##_maj##_##_min(__VA_ARGS__); \
_CRYPT_SYMVER(__##_public_sym##_v##_maj##_##_min, _public_sym, _prefix_str "CRYPTSETUP_", _maj, _min) \
_ret __##_public_sym##_v##_maj##_##_min(__VA_ARGS__)
#ifdef _CRYPT_SYMVER
# define CRYPT_SYMBOL_EXPORT_OLD(_ret, _public_sym, _maj, _min, ...) \
_CRYPT_FUNC(_public_sym, "@", _maj, _min, _ret, __VA_ARGS__)
# define CRYPT_SYMBOL_EXPORT_NEW(_ret, _public_sym, _maj, _min, ...) \
_CRYPT_FUNC(_public_sym, "@@", _maj, _min, _ret, __VA_ARGS__)
#else /* no support for symbol versioning at all */
# define CRYPT_SYMBOL_EXPORT_OLD(_ret, _public_sym, _maj, _min, ...) \
static inline __attribute__((unused)) \
_ret __##_public_sym##_v##_maj##_##_min(__VA_ARGS__)
# define CRYPT_SYMBOL_EXPORT_NEW(_ret, _public_sym, _maj, _min, ...) \
_ret _public_sym(__VA_ARGS__)
#endif
#endif /* _LIBCRYPTSETUP_SYMVER_H */
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