openssl/include/internal/thread_once.h

138 lines
5.0 KiB
C

/*
* Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <openssl/crypto.h>
/*
* DEFINE_RUN_ONCE: Define an initialiser function that should be run exactly
* once. It takes no arguments and returns and int result (1 for success or
* 0 for failure). Typical usage might be:
*
* DEFINE_RUN_ONCE(myinitfunc)
* {
* do_some_initialisation();
* if (init_is_successful())
* return 1;
*
* return 0;
* }
*/
#define DEFINE_RUN_ONCE(init) \
static int init(void); \
int init##_ossl_ret_ = 0; \
void init##_ossl_(void) \
{ \
init##_ossl_ret_ = init(); \
} \
static int init(void)
/*
* DECLARE_RUN_ONCE: Declare an initialiser function that should be run exactly
* once that has been defined in another file via DEFINE_RUN_ONCE().
*/
#define DECLARE_RUN_ONCE(init) \
extern int init##_ossl_ret_; \
void init##_ossl_(void);
/*
* DEFINE_RUN_ONCE_STATIC: Define an initialiser function that should be run
* exactly once. This function will be declared as static within the file. It
* takes no arguments and returns and int result (1 for success or 0 for
* failure). Typical usage might be:
*
* DEFINE_RUN_ONCE_STATIC(myinitfunc)
* {
* do_some_initialisation();
* if (init_is_successful())
* return 1;
*
* return 0;
* }
*/
#define DEFINE_RUN_ONCE_STATIC(init) \
static int init(void); \
static int init##_ossl_ret_ = 0; \
static void init##_ossl_(void) \
{ \
init##_ossl_ret_ = init(); \
} \
static int init(void)
/*
* DEFINE_RUN_ONCE_STATIC_ALT: Define an alternative initialiser function. This
* function will be declared as static within the file. It takes no arguments
* and returns an int result (1 for success or 0 for failure). An alternative
* initialiser function is expected to be associated with a primary initialiser
* function defined via DEFINE_ONCE_STATIC where both functions use the same
* CRYPTO_ONCE object to synchronise. Where an alternative initialiser function
* is used only one of the primary or the alternative initialiser function will
* ever be called - and that function will be called exactly once. Definition
* of an alternative initialiser function MUST occur AFTER the definition of the
* primary initialiser function.
*
* Typical usage might be:
*
* DEFINE_RUN_ONCE_STATIC(myinitfunc)
* {
* do_some_initialisation();
* if (init_is_successful())
* return 1;
*
* return 0;
* }
*
* DEFINE_RUN_ONCE_STATIC_ALT(myaltinitfunc, myinitfunc)
* {
* do_some_alternative_initialisation();
* if (init_is_successful())
* return 1;
*
* return 0;
* }
*/
#define DEFINE_RUN_ONCE_STATIC_ALT(initalt, init) \
static int initalt(void); \
static void initalt##_ossl_(void) \
{ \
init##_ossl_ret_ = initalt(); \
} \
static int initalt(void)
/*
* RUN_ONCE - use CRYPTO_THREAD_run_once, and check if the init succeeded
* @once: pointer to static object of type CRYPTO_ONCE
* @init: function name that was previously given to DEFINE_RUN_ONCE,
* DEFINE_RUN_ONCE_STATIC or DECLARE_RUN_ONCE. This function
* must return 1 for success or 0 for failure.
*
* The return value is 1 on success (*) or 0 in case of error.
*
* (*) by convention, since the init function must return 1 on success.
*/
#define RUN_ONCE(once, init) \
(CRYPTO_THREAD_run_once(once, init##_ossl_) ? init##_ossl_ret_ : 0)
/*
* RUN_ONCE_ALT - use CRYPTO_THREAD_run_once, to run an alternative initialiser
* function and check if that initialisation succeeded
* @once: pointer to static object of type CRYPTO_ONCE
* @initalt: alternative initialiser function name that was previously given to
* DEFINE_RUN_ONCE_STATIC_ALT. This function must return 1 for
* success or 0 for failure.
* @init: primary initialiser function name that was previously given to
* DEFINE_RUN_ONCE_STATIC. This function must return 1 for success or
* 0 for failure.
*
* The return value is 1 on success (*) or 0 in case of error.
*
* (*) by convention, since the init function must return 1 on success.
*/
#define RUN_ONCE_ALT(once, initalt, init) \
(CRYPTO_THREAD_run_once(once, initalt##_ossl_) ? init##_ossl_ret_ : 0)