include/internal/thread_once.h

   1 /*
   2  * Copyright 1995-2016 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 #define DEFINE_RUN_ONCE(init)                   \
  13     static int init(void);                     \
  14     int init##_ossl_ret_ = 0;                   \
  15     void init##_ossl_(void)                     \
  16     {                                           \
  17         init##_ossl_ret_ = init();              \
  18     }                                           \
  19     static int init(void)
  20 #define DECLARE_RUN_ONCE(init)                  \
  21     extern int init##_ossl_ret_;                \
  22     void init##_ossl_(void);
  23
  24 #define DEFINE_RUN_ONCE_STATIC(init)            \
  25     static int init(void);                     \
  26     static int init##_ossl_ret_ = 0;            \
  27     static void init##_ossl_(void)              \
  28     {                                           \
  29         init##_ossl_ret_ = init();              \
  30     }                                           \
  31     static int init(void)
  32
  33 /*
  34  * RUN_ONCE - use CRYPTO_THREAD_run_once, and check if the init succeeded
  35  * @once: pointer to static object of type CRYPTO_ONCE
  36  * @init: function name that was previously given to DEFINE_RUN_ONCE,
  37  *        DEFINE_RUN_ONCE_STATIC or DECLARE_RUN_ONCE.  This function
  38  *        must return 1 for success or 0 for failure.
  39  *
  40  * The return value is 1 on success (*) or 0 in case of error.
  41  *
  42  * (*) by convention, since the init function must return 1 on success.
  43  */
  44 #define RUN_ONCE(once, init)                                            \
  45     (CRYPTO_THREAD_run_once(once, init##_ossl_) ? init##_ossl_ret_ : 0)