90 lines
3.3 KiB
C
90 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Helpers for defining versioned symbols
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*
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* Copyright (C) 2021-2024 Red Hat, Inc. All rights reserved.
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*/
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#ifndef _LIBCRYPTSETUP_SYMVER_H
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#define _LIBCRYPTSETUP_SYMVER_H
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/*
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* Note on usage:
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*
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* Do not use CRYPT_SYMBOL_EXPORT_NEW and CRYPT_SYMBOL_EXPORT_OLD on public
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* symbols being exported only once. Linker will handle it automatically as
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* always.
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*
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* It's supposed to be used only with symbols that are exported in at least
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* two versions simultaneously as follows:
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*
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* - the latest version is marked with _NEW variant and all other compatible
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* symbols should be marked with _OLD variant
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*
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* Examples:
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*
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* - int crypt_func_X(unsigned *x, long y) gets introduced in CRYPTSETUP_2.4.
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*
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* No need to use any macro referenced here, just add proper version
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* mapping in libcryptsetup.sym file.
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*
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* In later version CRYPTSETUP_2.5 symbol crypt_func_X has to fixed
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* in incompatible way by adding new function parameter. The new version
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* has to be added in mapping file libcryptsetup.sym as well.
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*
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* The definition of compatible function gets prefixed with following macro:
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*
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* CRYPT_SYMBOL_EXPORT_OLD(int, crypt_func_X, 2, 4,
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* unsigned *x, long y)
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* {
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* function body
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* }
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*
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* Whereas new version introduced in CRYPTSETUP_2.5 is defined as follows:
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*
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* CRYPT_SYMBOL_EXPORT_NEW(int, crypt_func_X, 2, 5,
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* unsigned *x, long y, void *new_parameter)
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* {
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* function body
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* }
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*
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* If in later version CRYPTSETUP_2.6 yet another version of crypt_func_X gets
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* introduced it will be prefixed with CRYPT_SYMBOL_EXPORT_NEW(int, crypt_func_X, 2, 6...)
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* macro and all previous versions CRYPTSETUP_2.4 and CRYPTSETUP_2.5 will be
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* under CRYPT_SYMBOL_EXPORT_OLD(int, crypt_func_X, ...) macro
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*/
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#if HAVE_ATTRIBUTE_SYMVER
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# define _CRYPT_SYMVER(_local_sym, _public_sym, _ver_str, _maj, _min) \
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__attribute__((__symver__(#_public_sym _ver_str #_maj "." #_min)))
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#endif
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#if !defined(_CRYPT_SYMVER) && (defined(__GNUC__) || defined(__clang__))
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# define _CRYPT_SYMVER(_local_sym, _public_sym, _ver_str, _maj, _min) \
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__asm__(".symver " #_local_sym "," #_public_sym _ver_str #_maj "." #_min);
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#endif
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#define _CRYPT_FUNC(_public_sym, _prefix_str, _maj, _min, _ret, ...) \
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_ret __##_public_sym##_v##_maj##_##_min(__VA_ARGS__); \
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_CRYPT_SYMVER(__##_public_sym##_v##_maj##_##_min, _public_sym, _prefix_str "CRYPTSETUP_", _maj, _min) \
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_ret __##_public_sym##_v##_maj##_##_min(__VA_ARGS__)
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#ifdef _CRYPT_SYMVER
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# define CRYPT_SYMBOL_EXPORT_OLD(_ret, _public_sym, _maj, _min, ...) \
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_CRYPT_FUNC(_public_sym, "@", _maj, _min, _ret, __VA_ARGS__)
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# define CRYPT_SYMBOL_EXPORT_NEW(_ret, _public_sym, _maj, _min, ...) \
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_CRYPT_FUNC(_public_sym, "@@", _maj, _min, _ret, __VA_ARGS__)
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#else /* no support for symbol versioning at all */
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# define CRYPT_SYMBOL_EXPORT_OLD(_ret, _public_sym, _maj, _min, ...) \
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static inline __attribute__((unused)) \
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_ret __##_public_sym##_v##_maj##_##_min(__VA_ARGS__)
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# define CRYPT_SYMBOL_EXPORT_NEW(_ret, _public_sym, _maj, _min, ...) \
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_ret _public_sym(__VA_ARGS__)
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#endif
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#endif /* _LIBCRYPTSETUP_SYMVER_H */
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