text: /**
   * \file platform.h
   *
   * \brief mbed TLS Platform abstraction layer
   *
   *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
   *  SPDX-License-Identifier: Apache-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.
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   */
  #ifndef MBEDTLS_PLATFORM_H
  #define MBEDTLS_PLATFORM_H
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #if defined(MBEDTLS_HAVE_TIME)
  #include "mbedtls/platform_time.h"
  #endif
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * \name SECTION: Module settings
   *
   * The configuration options you can set for this module are in this section.
   * Either change them in config.h or define them on the compiler command line.
   * \{
   */
  
  #if !defined(MBEDTLS_PLATFORM_NO_STD_FUNCTIONS)
  #include <stdio.h>
  #include <stdlib.h>
  #include <time.h>
  #if !defined(MBEDTLS_PLATFORM_STD_SNPRINTF)
  #if defined(_WIN32)
  #define MBEDTLS_PLATFORM_STD_SNPRINTF   mbedtls_platform_win32_snprintf /**< Default snprintf to use  */
  #else
  #define MBEDTLS_PLATFORM_STD_SNPRINTF   snprintf /**< Default snprintf to use  */
  #endif
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_PRINTF)
  #define MBEDTLS_PLATFORM_STD_PRINTF   printf /**< Default printf to use  */
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_FPRINTF)
  #define MBEDTLS_PLATFORM_STD_FPRINTF fprintf /**< Default fprintf to use */
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_CALLOC)
  #define MBEDTLS_PLATFORM_STD_CALLOC   calloc /**< Default allocator to use */
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_FREE)
  #define MBEDTLS_PLATFORM_STD_FREE       free /**< Default free to use */
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_EXIT)
  #define MBEDTLS_PLATFORM_STD_EXIT      exit /**< Default exit to use */
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_TIME)
  #define MBEDTLS_PLATFORM_STD_TIME       time    /**< Default time to use */
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_EXIT_SUCCESS)
  #define MBEDTLS_PLATFORM_STD_EXIT_SUCCESS  EXIT_SUCCESS /**< Default exit value to use */
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_EXIT_FAILURE)
  #define MBEDTLS_PLATFORM_STD_EXIT_FAILURE  EXIT_FAILURE /**< Default exit value to use */
  #endif
  #if defined(MBEDTLS_FS_IO)
  #if !defined(MBEDTLS_PLATFORM_STD_NV_SEED_READ)
  #define MBEDTLS_PLATFORM_STD_NV_SEED_READ   mbedtls_platform_std_nv_seed_read
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_NV_SEED_WRITE)
  #define MBEDTLS_PLATFORM_STD_NV_SEED_WRITE  mbedtls_platform_std_nv_seed_write
  #endif
  #if !defined(MBEDTLS_PLATFORM_STD_NV_SEED_FILE)
  #define MBEDTLS_PLATFORM_STD_NV_SEED_FILE   "seedfile"
  #endif
  #endif /* MBEDTLS_FS_IO */
  #else /* MBEDTLS_PLATFORM_NO_STD_FUNCTIONS */
  #if defined(MBEDTLS_PLATFORM_STD_MEM_HDR)
  #include MBEDTLS_PLATFORM_STD_MEM_HDR
  #endif
  #endif /* MBEDTLS_PLATFORM_NO_STD_FUNCTIONS */
  
  
  /* \} name SECTION: Module settings */
  
  /*
   * The function pointers for calloc and free
   */
  #if defined(MBEDTLS_PLATFORM_MEMORY)
  #if defined(MBEDTLS_PLATFORM_FREE_MACRO) && \
      defined(MBEDTLS_PLATFORM_CALLOC_MACRO)
  #define mbedtls_free       MBEDTLS_PLATFORM_FREE_MACRO
  #define mbedtls_calloc     MBEDTLS_PLATFORM_CALLOC_MACRO
  #else
  /* For size_t */
  #include <stddef.h>
  extern void * (*mbedtls_calloc)( size_t n, size_t size );
  extern void (*mbedtls_free)( void *ptr );
  
  /**
   * \brief   Set your own memory implementation function pointers
   *
   * \param calloc_func   the calloc function implementation
   * \param free_func     the free function implementation
   *
   * \return              0 if successful
   */
  int mbedtls_platform_set_calloc_free( void * (*calloc_func)( size_t, size_t ),
                                void (*free_func)( void * ) );
  #endif /* MBEDTLS_PLATFORM_FREE_MACRO && MBEDTLS_PLATFORM_CALLOC_MACRO */
  #else /* !MBEDTLS_PLATFORM_MEMORY */
  #define mbedtls_free       free
  #define mbedtls_calloc     calloc
  #endif /* MBEDTLS_PLATFORM_MEMORY && !MBEDTLS_PLATFORM_{FREE,CALLOC}_MACRO */
  
  /*
   * The function pointers for fprintf
   */
  #if defined(MBEDTLS_PLATFORM_FPRINTF_ALT)
  /* We need FILE * */
  #include <stdio.h>
  extern int (*mbedtls_fprintf)( FILE *stream, const char *format, ... );
  
  /**
   * \brief   Set your own fprintf function pointer
   *
   * \param fprintf_func   the fprintf function implementation
   *
   * \return              0
   */
  int mbedtls_platform_set_fprintf( int (*fprintf_func)( FILE *stream, const char *,
                                                 ... ) );
  #else
  #if defined(MBEDTLS_PLATFORM_FPRINTF_MACRO)
  #define mbedtls_fprintf    MBEDTLS_PLATFORM_FPRINTF_MACRO
  #else
  #define mbedtls_fprintf    fprintf
  #endif /* MBEDTLS_PLATFORM_FPRINTF_MACRO */
  #endif /* MBEDTLS_PLATFORM_FPRINTF_ALT */
  
  /*
   * The function pointers for printf
   */
  #if defined(MBEDTLS_PLATFORM_PRINTF_ALT)
  extern int (*mbedtls_printf)( const char *format, ... );
  
  /**
   * \brief   Set your own printf function pointer
   *
   * \param printf_func   the printf function implementation
   *
   * \return              0
   */
  int mbedtls_platform_set_printf( int (*printf_func)( const char *, ... ) );
  #else /* !MBEDTLS_PLATFORM_PRINTF_ALT */
  #if defined(MBEDTLS_PLATFORM_PRINTF_MACRO)
  #define mbedtls_printf     MBEDTLS_PLATFORM_PRINTF_MACRO
  #else
  #define mbedtls_printf     printf
  #endif /* MBEDTLS_PLATFORM_PRINTF_MACRO */
  #endif /* MBEDTLS_PLATFORM_PRINTF_ALT */
  
  /*
   * The function pointers for snprintf
   *
   * The snprintf implementation should conform to C99:
   * - it *must* always correctly zero-terminate the buffer
   *   (except when n == 0, then it must leave the buffer untouched)
   * - however it is acceptable to return -1 instead of the required length when
   *   the destination buffer is too short.
   */
  #if defined(_WIN32)
  /* For Windows (inc. MSYS2), we provide our own fixed implementation */
  int mbedtls_platform_win32_snprintf( char *s, size_t n, const char *fmt, ... );
  #endif
  
  #if defined(MBEDTLS_PLATFORM_SNPRINTF_ALT)
  extern int (*mbedtls_snprintf)( char * s, size_t n, const char * format, ... );
  
  /**
   * \brief   Set your own snprintf function pointer
   *
   * \param snprintf_func   the snprintf function implementation
   *
   * \return              0
   */
  int mbedtls_platform_set_snprintf( int (*snprintf_func)( char * s, size_t n,
                                                   const char * format, ... ) );
  #else /* MBEDTLS_PLATFORM_SNPRINTF_ALT */
  #if defined(MBEDTLS_PLATFORM_SNPRINTF_MACRO)
  #define mbedtls_snprintf   MBEDTLS_PLATFORM_SNPRINTF_MACRO
  #else
  #define mbedtls_snprintf   snprintf
  #endif /* MBEDTLS_PLATFORM_SNPRINTF_MACRO */
  #endif /* MBEDTLS_PLATFORM_SNPRINTF_ALT */
  
  /*
   * The function pointers for exit
   */
  #if defined(MBEDTLS_PLATFORM_EXIT_ALT)
  extern void (*mbedtls_exit)( int status );
  
  /**
   * \brief   Set your own exit function pointer
   *
   * \param exit_func   the exit function implementation
   *
   * \return              0
   */
  int mbedtls_platform_set_exit( void (*exit_func)( int status ) );
  #else
  #if defined(MBEDTLS_PLATFORM_EXIT_MACRO)
  #define mbedtls_exit   MBEDTLS_PLATFORM_EXIT_MACRO
  #else
  #define mbedtls_exit   exit
  #endif /* MBEDTLS_PLATFORM_EXIT_MACRO */
  #endif /* MBEDTLS_PLATFORM_EXIT_ALT */
  
  /*
   * The default exit values
   */
  #if defined(MBEDTLS_PLATFORM_STD_EXIT_SUCCESS)
  #define MBEDTLS_EXIT_SUCCESS MBEDTLS_PLATFORM_STD_EXIT_SUCCESS
  #else
  #define MBEDTLS_EXIT_SUCCESS 0
  #endif
  #if defined(MBEDTLS_PLATFORM_STD_EXIT_FAILURE)
  #define MBEDTLS_EXIT_FAILURE MBEDTLS_PLATFORM_STD_EXIT_FAILURE
  #else
  #define MBEDTLS_EXIT_FAILURE 1
  #endif
  
  /*
   * The function pointers for reading from and writing a seed file to
   * Non-Volatile storage (NV) in a platform-independent way
   *
   * Only enabled when the NV seed entropy source is enabled
   */
  #if defined(MBEDTLS_ENTROPY_NV_SEED)
  #if !defined(MBEDTLS_PLATFORM_NO_STD_FUNCTIONS) && defined(MBEDTLS_FS_IO)
  /* Internal standard platform definitions */
  int mbedtls_platform_std_nv_seed_read( unsigned char *buf, size_t buf_len );
  int mbedtls_platform_std_nv_seed_write( unsigned char *buf, size_t buf_len );
  #endif
  
  #if defined(MBEDTLS_PLATFORM_NV_SEED_ALT)
  extern int (*mbedtls_nv_seed_read)( unsigned char *buf, size_t buf_len );
  extern int (*mbedtls_nv_seed_write)( unsigned char *buf, size_t buf_len );
  
  /**
   * \brief   Set your own seed file writing/reading functions
   *
   * \param   nv_seed_read_func   the seed reading function implementation
   * \param   nv_seed_write_func  the seed writing function implementation
   *
   * \return              0
   */
  int mbedtls_platform_set_nv_seed(
              int (*nv_seed_read_func)( unsigned char *buf, size_t buf_len ),
              int (*nv_seed_write_func)( unsigned char *buf, size_t buf_len )
              );
  #else
  #if defined(MBEDTLS_PLATFORM_NV_SEED_READ_MACRO) && \
      defined(MBEDTLS_PLATFORM_NV_SEED_WRITE_MACRO)
  #define mbedtls_nv_seed_read    MBEDTLS_PLATFORM_NV_SEED_READ_MACRO
  #define mbedtls_nv_seed_write   MBEDTLS_PLATFORM_NV_SEED_WRITE_MACRO
  #else
  #define mbedtls_nv_seed_read    mbedtls_platform_std_nv_seed_read
  #define mbedtls_nv_seed_write   mbedtls_platform_std_nv_seed_write
  #endif
  #endif /* MBEDTLS_PLATFORM_NV_SEED_ALT */
  #endif /* MBEDTLS_ENTROPY_NV_SEED */
  
  #if !defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
  
  /**
   * \brief   Platform context structure
   *
   * \note    This structure may be used to assist platform-specific
   *          setup/teardown operations.
   */
  typedef struct {
      char dummy; /**< Placeholder member as empty structs are not portable */
  }
  mbedtls_platform_context;
  
  #else
  #include "platform_alt.h"
  #endif /* !MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT */
  
  /**
   * \brief   Perform any platform initialisation operations
   *
   * \param   ctx     mbed TLS context
   *
   * \return  0 if successful
   *
   * \note    This function is intended to allow platform specific initialisation,
   *          and should be called before any other library functions. Its
   *          implementation is platform specific, and by default, unless platform
   *          specific code is provided, it does nothing.
   *
   *          Its use and whether its necessary to be called is dependent on the
   *          platform.
   */
  int mbedtls_platform_setup( mbedtls_platform_context *ctx );
  /**
   * \brief   Perform any platform teardown operations
   *
   * \param   ctx     mbed TLS context
   *
   * \note    This function should be called after every other mbed TLS module has
   *          been correctly freed using the appropriate free function.
   *          Its implementation is platform specific, and by default, unless
   *          platform specific code is provided, it does nothing.
   *
   *          Its use and whether its necessary to be called is dependent on the
   *          platform.
   */
  void mbedtls_platform_teardown( mbedtls_platform_context *ctx );
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* platform.h */
  