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      1 /*
      2  * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
      3  *
      4  * Licensed under the OpenSSL license (the "License").  You may not use
      5  * this file except in compliance with the License.  You can obtain a copy
      6  * in the file LICENSE in the source distribution or at
      7  * https://www.openssl.org/source/license.html
      8  */
      9 
     10 #include <openssl/crypto.h>
     11 
     12 /*
     13  * DEFINE_RUN_ONCE: Define an initialiser function that should be run exactly
     14  * once. It takes no arguments and returns and int result (1 for success or
     15  * 0 for failure). Typical usage might be:
     16  *
     17  * DEFINE_RUN_ONCE(myinitfunc)
     18  * {
     19  *     do_some_initialisation();
     20  *     if (init_is_successful())
     21  *         return 1;
     22  *
     23  *     return 0;
     24  * }
     25  */
     26 #define DEFINE_RUN_ONCE(init)                   \
     27     static int init(void);                     \
     28     int init##_ossl_ret_ = 0;                   \
     29     void init##_ossl_(void)                     \
     30     {                                           \
     31         init##_ossl_ret_ = init();              \
     32     }                                           \
     33     static int init(void)
     34 
     35 /*
     36  * DECLARE_RUN_ONCE: Declare an initialiser function that should be run exactly
     37  * once that has been defined in another file via DEFINE_RUN_ONCE().
     38  */
     39 #define DECLARE_RUN_ONCE(init)                  \
     40     extern int init##_ossl_ret_;                \
     41     void init##_ossl_(void);
     42 
     43 /*
     44  * DEFINE_RUN_ONCE_STATIC: Define an initialiser function that should be run
     45  * exactly once. This function will be declared as static within the file. It
     46  * takes no arguments and returns and int result (1 for success or 0 for
     47  * failure). Typical usage might be:
     48  *
     49  * DEFINE_RUN_ONCE_STATIC(myinitfunc)
     50  * {
     51  *     do_some_initialisation();
     52  *     if (init_is_successful())
     53  *         return 1;
     54  *
     55  *     return 0;
     56  * }
     57  */
     58 #define DEFINE_RUN_ONCE_STATIC(init)            \
     59     static int init(void);                     \
     60     static int init##_ossl_ret_ = 0;            \
     61     static void init##_ossl_(void)              \
     62     {                                           \
     63         init##_ossl_ret_ = init();              \
     64     }                                           \
     65     static int init(void)
     66 
     67 /*
     68  * DEFINE_RUN_ONCE_STATIC_ALT: Define an alternative initialiser function. This
     69  * function will be declared as static within the file. It takes no arguments
     70  * and returns an int result (1 for success or 0 for failure). An alternative
     71  * initialiser function is expected to be associated with a primary initialiser
     72  * function defined via DEFINE_ONCE_STATIC where both functions use the same
     73  * CRYPTO_ONCE object to synchronise. Where an alternative initialiser function
     74  * is used only one of the primary or the alternative initialiser function will
     75  * ever be called - and that function will be called exactly once. Definition
     76  * of an alternative initialiser function MUST occur AFTER the definition of the
     77  * primary initialiser function.
     78  *
     79  * Typical usage might be:
     80  *
     81  * DEFINE_RUN_ONCE_STATIC(myinitfunc)
     82  * {
     83  *     do_some_initialisation();
     84  *     if (init_is_successful())
     85  *         return 1;
     86  *
     87  *     return 0;
     88  * }
     89  *
     90  * DEFINE_RUN_ONCE_STATIC_ALT(myaltinitfunc, myinitfunc)
     91  * {
     92  *     do_some_alternative_initialisation();
     93  *     if (init_is_successful())
     94  *         return 1;
     95  *
     96  *     return 0;
     97  * }
     98  */
     99 #define DEFINE_RUN_ONCE_STATIC_ALT(initalt, init) \
    100     static int initalt(void);                     \
    101     static void initalt##_ossl_(void)             \
    102     {                                             \
    103         init##_ossl_ret_ = initalt();             \
    104     }                                             \
    105     static int initalt(void)
    106 
    107 /*
    108  * RUN_ONCE - use CRYPTO_THREAD_run_once, and check if the init succeeded
    109  * @once: pointer to static object of type CRYPTO_ONCE
    110  * @init: function name that was previously given to DEFINE_RUN_ONCE,
    111  *        DEFINE_RUN_ONCE_STATIC or DECLARE_RUN_ONCE.  This function
    112  *        must return 1 for success or 0 for failure.
    113  *
    114  * The return value is 1 on success (*) or 0 in case of error.
    115  *
    116  * (*) by convention, since the init function must return 1 on success.
    117  */
    118 #define RUN_ONCE(once, init)                                            \
    119     (CRYPTO_THREAD_run_once(once, init##_ossl_) ? init##_ossl_ret_ : 0)
    120 
    121 /*
    122  * RUN_ONCE_ALT - use CRYPTO_THREAD_run_once, to run an alternative initialiser
    123  *                function and check if that initialisation succeeded
    124  * @once:    pointer to static object of type CRYPTO_ONCE
    125  * @initalt: alternative initialiser function name that was previously given to
    126  *           DEFINE_RUN_ONCE_STATIC_ALT.  This function must return 1 for
    127  *           success or 0 for failure.
    128  * @init:    primary initialiser function name that was previously given to
    129  *           DEFINE_RUN_ONCE_STATIC.  This function must return 1 for success or
    130  *           0 for failure.
    131  *
    132  * The return value is 1 on success (*) or 0 in case of error.
    133  *
    134  * (*) by convention, since the init function must return 1 on success.
    135  */
    136 #define RUN_ONCE_ALT(once, initalt, init)                               \
    137     (CRYPTO_THREAD_run_once(once, initalt##_ossl_) ? init##_ossl_ret_ : 0)
    138