text: /**
   * \file platform_util.h
   *
   * \brief Common and shared functions used by multiple modules in the Mbed TLS
   *        library.
   */
  /*
   *  Copyright The Mbed TLS Contributors
   *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
   *
   *  This file is provided under the Apache License 2.0, or the
   *  GNU General Public License v2.0 or later.
   *
   *  **********
   *  Apache License 2.0:
   *
   *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   *  not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  **********
   *
   *  **********
   *  GNU General Public License v2.0 or later:
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License along
   *  with this program; if not, write to the Free Software Foundation, Inc.,
   *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   *  **********
   */
  #ifndef BLCRYPTO_SUITE_PLATFORM_UTIL_H
  #define BLCRYPTO_SUITE_PLATFORM_UTIL_H
  
  #if !defined(BLCRYPTO_SUITE_CONFIG_FILE)
  #include "blcrypto_suite/blcrypto_suite_config.h"
  #else
  #include BLCRYPTO_SUITE_CONFIG_FILE
  #endif
  
  #include <stddef.h>
  #if defined(BLCRYPTO_SUITE_HAVE_TIME_DATE)
  #include "platform_time.h"
  #include <time.h>
  #endif /* BLCRYPTO_SUITE_HAVE_TIME_DATE */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #if defined(BLCRYPTO_SUITE_CHECK_PARAMS)
  
  #if defined(BLCRYPTO_SUITE_CHECK_PARAMS_ASSERT)
  /* Allow the user to define BLCRYPTO_SUITE_PARAM_FAILED to something like assert
   * (which is what our config.h suggests). */
  #include <assert.h>
  #endif /* BLCRYPTO_SUITE_CHECK_PARAMS_ASSERT */
  
  #if defined(BLCRYPTO_SUITE_PARAM_FAILED)
  /** An alternative definition of BLCRYPTO_SUITE_PARAM_FAILED has been set in config.h.
   *
   * This flag can be used to check whether it is safe to assume that
   * BLCRYPTO_SUITE_PARAM_FAILED() will expand to a call to blcrypto_suite_param_failed().
   */
  #define BLCRYPTO_SUITE_PARAM_FAILED_ALT
  
  #elif defined(BLCRYPTO_SUITE_CHECK_PARAMS_ASSERT)
  #define BLCRYPTO_SUITE_PARAM_FAILED( cond ) assert( cond )
  #define BLCRYPTO_SUITE_PARAM_FAILED_ALT
  
  #else /* BLCRYPTO_SUITE_PARAM_FAILED */
  #define BLCRYPTO_SUITE_PARAM_FAILED( cond ) \
      blcrypto_suite_param_failed( #cond, __FILE__, __LINE__ )
  
  /**
   * \brief       User supplied callback function for parameter validation failure.
   *              See #BLCRYPTO_SUITE_CHECK_PARAMS for context.
   *
   *              This function will be called unless an alternative treatement
   *              is defined through the #BLCRYPTO_SUITE_PARAM_FAILED macro.
   *
   *              This function can return, and the operation will be aborted, or
   *              alternatively, through use of setjmp()/longjmp() can resume
   *              execution in the application code.
   *
   * \param failure_condition The assertion that didn't hold.
   * \param file  The file where the assertion failed.
   * \param line  The line in the file where the assertion failed.
   */
  void blcrypto_suite_param_failed( const char *failure_condition,
                             const char *file,
                             int line );
  #endif /* BLCRYPTO_SUITE_PARAM_FAILED */
  
  /* Internal macro meant to be called only from within the library. */
  #define BLCRYPTO_SUITE_INTERNAL_VALIDATE_RET( cond, ret )  \
      do {                                            \
          if( !(cond) )                               \
          {                                           \
              BLCRYPTO_SUITE_PARAM_FAILED( cond );           \
              return( ret );                          \
          }                                           \
      } while( 0 )
  
  /* Internal macro meant to be called only from within the library. */
  #define BLCRYPTO_SUITE_INTERNAL_VALIDATE( cond )           \
      do {                                            \
          if( !(cond) )                               \
          {                                           \
              BLCRYPTO_SUITE_PARAM_FAILED( cond );           \
              return;                                 \
          }                                           \
      } while( 0 )
  
  #else /* BLCRYPTO_SUITE_CHECK_PARAMS */
  
  /* Internal macros meant to be called only from within the library. */
  #define BLCRYPTO_SUITE_INTERNAL_VALIDATE_RET( cond, ret )  do { } while( 0 )
  #define BLCRYPTO_SUITE_INTERNAL_VALIDATE( cond )           do { } while( 0 )
  
  #endif /* BLCRYPTO_SUITE_CHECK_PARAMS */
  
  /* Internal helper macros for deprecating API constants. */
  #if !defined(BLCRYPTO_SUITE_DEPRECATED_REMOVED)
  #if defined(BLCRYPTO_SUITE_DEPRECATED_WARNING)
  /* Deliberately don't (yet) export BLCRYPTO_SUITE_DEPRECATED here
   * to avoid conflict with other headers which define and use
   * it, too. We might want to move all these definitions here at
   * some point for uniformity. */
  #define BLCRYPTO_SUITE_DEPRECATED __attribute__((deprecated))
  BLCRYPTO_SUITE_DEPRECATED typedef char const * blcrypto_suite_deprecated_string_constant_t;
  #define BLCRYPTO_SUITE_DEPRECATED_STRING_CONSTANT( VAL )       \
      ( (blcrypto_suite_deprecated_string_constant_t) ( VAL ) )
  BLCRYPTO_SUITE_DEPRECATED typedef int blcrypto_suite_deprecated_numeric_constant_t;
  #define BLCRYPTO_SUITE_DEPRECATED_NUMERIC_CONSTANT( VAL )       \
      ( (blcrypto_suite_deprecated_numeric_constant_t) ( VAL ) )
  #undef BLCRYPTO_SUITE_DEPRECATED
  #else /* BLCRYPTO_SUITE_DEPRECATED_WARNING */
  #define BLCRYPTO_SUITE_DEPRECATED_STRING_CONSTANT( VAL ) VAL
  #define BLCRYPTO_SUITE_DEPRECATED_NUMERIC_CONSTANT( VAL ) VAL
  #endif /* BLCRYPTO_SUITE_DEPRECATED_WARNING */
  #endif /* BLCRYPTO_SUITE_DEPRECATED_REMOVED */
  
  /**
   * \brief       Securely zeroize a buffer
   *
   *              The function is meant to wipe the data contained in a buffer so
   *              that it can no longer be recovered even if the program memory
   *              is later compromised. Call this function on sensitive data
   *              stored on the stack before returning from a function, and on
   *              sensitive data stored on the heap before freeing the heap
   *              object.
   *
   *              It is extremely difficult to guarantee that calls to
   *              blcrypto_suite_platform_zeroize() are not removed by aggressive
   *              compiler optimizations in a portable way. For this reason, Mbed
   *              TLS provides the configuration option
   *              BLCRYPTO_SUITE_PLATFORM_ZEROIZE_ALT, which allows users to configure
   *              blcrypto_suite_platform_zeroize() to use a suitable implementation for
   *              their platform and needs
   *
   * \param buf   Buffer to be zeroized
   * \param len   Length of the buffer in bytes
   *
   */
  void blcrypto_suite_platform_zeroize( void *buf, size_t len );
  
  #if defined(BLCRYPTO_SUITE_HAVE_TIME_DATE)
  /**
   * \brief      Platform-specific implementation of gmtime_r()
   *
   *             The function is a thread-safe abstraction that behaves
   *             similarly to the gmtime_r() function from Unix/POSIX.
   *
   *             Mbed TLS will try to identify the underlying platform and
   *             make use of an appropriate underlying implementation (e.g.
   *             gmtime_r() for POSIX and gmtime_s() for Windows). If this is
   *             not possible, then gmtime() will be used. In this case, calls
   *             from the library to gmtime() will be guarded by the mutex
   *             blcrypto_suite_threading_gmtime_mutex if BLCRYPTO_SUITE_THREADING_C is
   *             enabled. It is recommended that calls from outside the library
   *             are also guarded by this mutex.
   *
   *             If BLCRYPTO_SUITE_PLATFORM_GMTIME_R_ALT is defined, then Mbed TLS will
   *             unconditionally use the alternative implementation for
   *             blcrypto_suite_platform_gmtime_r() supplied by the user at compile time.
   *
   * \param tt     Pointer to an object containing time (in seconds) since the
   *               epoch to be converted
   * \param tm_buf Pointer to an object where the results will be stored
   *
   * \return      Pointer to an object of type struct tm on success, otherwise
   *              NULL
   */
  struct tm *blcrypto_suite_platform_gmtime_r( const blcrypto_suite_time_t *tt,
                                        struct tm *tm_buf );
  #endif /* BLCRYPTO_SUITE_HAVE_TIME_DATE */
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* BLCRYPTO_SUITE_PLATFORM_UTIL_H */
  