include/internal/thread_once.h

   1 /*
   2  * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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  * Initialisation of global data should never happen via "RUN_ONCE" inside the
  14  * FIPS module. Global data should instead always be associated with a specific
  15  * OPENSSL_CTX object. In this way data will get cleaned up correctly when the
  16  * module gets unloaded.
  17  */
  18 #if !defined(FIPS_MODULE) || defined(ALLOW_RUN_ONCE_IN_FIPS)
  19 /*
  20  * DEFINE_RUN_ONCE: Define an initialiser function that should be run exactly
  21  * once. It takes no arguments and returns and int result (1 for success or
  22  * 0 for failure). Typical usage might be:
  23  *
  24  * DEFINE_RUN_ONCE(myinitfunc)
  25  * {
  26  *     do_some_initialisation();
  27  *     if (init_is_successful())
  28  *         return 1;
  29  *
  30  *     return 0;
  31  * }
  32  */
  33 # define DEFINE_RUN_ONCE(init)                   \
  34     static int init(void);                     \
  35     int init##_ossl_ret_ = 0;                   \
  36     void init##_ossl_(void)                     \
  37     {                                           \
  38         init##_ossl_ret_ = init();              \
  39     }                                           \
  40     static int init(void)
  41
  42 /*
  43  * DECLARE_RUN_ONCE: Declare an initialiser function that should be run exactly
  44  * once that has been defined in another file via DEFINE_RUN_ONCE().
  45  */
  46 # define DECLARE_RUN_ONCE(init)                  \
  47     extern int init##_ossl_ret_;                \
  48     void init##_ossl_(void);
  49
  50 /*
  51  * DEFINE_RUN_ONCE_STATIC: Define an initialiser function that should be run
  52  * exactly once. This function will be declared as static within the file. It
  53  * takes no arguments and returns and int result (1 for success or 0 for
  54  * failure). Typical usage might be:
  55  *
  56  * DEFINE_RUN_ONCE_STATIC(myinitfunc)
  57  * {
  58  *     do_some_initialisation();
  59  *     if (init_is_successful())
  60  *         return 1;
  61  *
  62  *     return 0;
  63  * }
  64  */
  65 # define DEFINE_RUN_ONCE_STATIC(init)            \
  66     static int init(void);                     \
  67     static int init##_ossl_ret_ = 0;            \
  68     static void init##_ossl_(void)              \
  69     {                                           \
  70         init##_ossl_ret_ = init();              \
  71     }                                           \
  72     static int init(void)
  73
  74 /*
  75  * DEFINE_RUN_ONCE_STATIC_ALT: Define an alternative initialiser function. This
  76  * function will be declared as static within the file. It takes no arguments
  77  * and returns and int result (1 for success or 0 for failure). An alternative
  78  * initialiser function is expected to be associated with a primary initialiser
  79  * function defined via DEFINE_ONCE_STATIC where both functions use the same
  80  * CRYPTO_ONCE object to synchronise. Where an alternative initialiser function
  81  * is used only one of the primary or the alternative initialiser function will
  82  * ever be called - and that function will be called exactly once. Definition
  83  * of an alternative initialiser function MUST occur AFTER the definition of the
  84  * primary initialiser function.
  85  *
  86  * Typical usage might be:
  87  *
  88  * DEFINE_RUN_ONCE_STATIC(myinitfunc)
  89  * {
  90  *     do_some_initialisation();
  91  *     if (init_is_successful())
  92  *         return 1;
  93  *
  94  *     return 0;
  95  * }
  96  *
  97  * DEFINE_RUN_ONCE_STATIC_ALT(myaltinitfunc, myinitfunc)
  98  * {
  99  *     do_some_alternative_initialisation();
 100  *     if (init_is_successful())
 101  *         return 1;
 102  *
 103  *     return 0;
 104  * }
 105  */
 106 # define DEFINE_RUN_ONCE_STATIC_ALT(initalt, init) \
 107     static int initalt(void);                     \
 108     static void initalt##_ossl_(void)             \
 109     {                                             \
 110         init##_ossl_ret_ = initalt();             \
 111     }                                             \
 112     static int initalt(void)
 113
 114 /*
 115  * RUN_ONCE - use CRYPTO_THREAD_run_once, and check if the init succeeded
 116  * @once: pointer to static object of type CRYPTO_ONCE
 117  * @init: function name that was previously given to DEFINE_RUN_ONCE,
 118  *        DEFINE_RUN_ONCE_STATIC or DECLARE_RUN_ONCE.  This function
 119  *        must return 1 for success or 0 for failure.
 120  *
 121  * The return value is 1 on success (*) or 0 in case of error.
 122  *
 123  * (*) by convention, since the init function must return 1 on success.
 124  */
 125 # define RUN_ONCE(once, init)                                            \
 126     (CRYPTO_THREAD_run_once(once, init##_ossl_) ? init##_ossl_ret_ : 0)
 127
 128 /*
 129  * RUN_ONCE_ALT - use CRYPTO_THREAD_run_once, to run an alternative initialiser
 130  *                function and check if that initialisation succeeded
 131  * @once:    pointer to static object of type CRYPTO_ONCE
 132  * @initalt: alternative initialiser function name that was previously given to
 133  *           DEFINE_RUN_ONCE_STATIC_ALT.  This function must return 1 for
 134  *           success or 0 for failure.
 135  * @init:    primary initialiser function name that was previously given to
 136  *           DEFINE_RUN_ONCE_STATIC.  This function must return 1 for success or
 137  *           0 for failure.
 138  *
 139  * The return value is 1 on success (*) or 0 in case of error.
 140  *
 141  * (*) by convention, since the init function must return 1 on success.
 142  */
 143 # define RUN_ONCE_ALT(once, initalt, init)                               \
 144     (CRYPTO_THREAD_run_once(once, initalt##_ossl_) ? init##_ossl_ret_ : 0)
 145
 146 #endif /* FIPS_MODULE */