kc3-lang/libbsd/src/md5.c

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• Hash : 31f034e3
  Author :
  Date : 2021-02-09T05:57:37
  

  Switch libmd wrapper to use dlsym() Switch from the previous versioned symbol implementation which required users to also link against the message digest provider explicitly, or they would fail to find the symbols, to an implementation that loads the symbols from the linked library providing the functions using dlsym(), thus preserving backwards compatibility.

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• src/md5.c

• /*
   * Copyright © 2021 Guillem Jover <guillem@hadrons.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
   * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
   * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <stddef.h>
  #include <stdlib.h>
  #include <dlfcn.h>
  #include <md5.h>
  
  static void (*libmd_MD5Init)(MD5_CTX *);
  static void (*libmd_MD5Update)(MD5_CTX *, const uint8_t *, size_t);
  static void (*libmd_MD5Pad)(MD5_CTX *);
  static void (*libmd_MD5Final)(uint8_t [MD5_DIGEST_LENGTH], MD5_CTX *);
  static void (*libmd_MD5Transform)(uint32_t [4], const uint8_t [MD5_BLOCK_LENGTH]);
  static char *(*libmd_MD5End)(MD5_CTX *, char *);
  static char *(*libmd_MD5File)(const char *, char *);
  static char *(*libmd_MD5FileChunk)(const char *, char *, off_t, off_t);
  static char *(*libmd_MD5Data)(const uint8_t *, size_t, char *);
  
  static void *
  libmd_loader(const char *symbol)
  {
  	void *func;
  
  	func = dlsym(RTLD_NEXT, symbol);
  	if (func == NULL) {
  		fprintf(stderr,
  		        "libbsd: cannot find wrapped symbol %s in libc or libmd\n",
  		        symbol);
  		abort();
  	}
  
  	return func;
  }
  
  #define libmd_wrapper(symbol) \
  	if (libmd_ ## symbol == NULL) \
  		libmd_ ## symbol = libmd_loader(#symbol)
  
  void
  MD5Init(MD5_CTX *context)
  {
  	libmd_wrapper(MD5Init);
  	libmd_MD5Init(context);
  }
  
  void
  MD5Update(MD5_CTX *context, const uint8_t *data, size_t len)
  {
  	libmd_wrapper(MD5Update);
  	libmd_MD5Update(context, data, len);
  }
  
  void
  MD5Pad(MD5_CTX *context)
  {
  	libmd_wrapper(MD5Pad);
  	libmd_MD5Pad(context);
  }
  
  void
  MD5Final(uint8_t digest[MD5_DIGEST_LENGTH], MD5_CTX *context)
  {
  	libmd_wrapper(MD5Final);
  	libmd_MD5Final(digest, context);
  }
  
  void
  MD5Transform(uint32_t state[4], const uint8_t block[MD5_BLOCK_LENGTH])
  {
  	libmd_wrapper(MD5Transform);
  	libmd_MD5Transform(state, block);
  }
  
  char *
  MD5End(MD5_CTX *context, char *buf)
  {
  	libmd_wrapper(MD5End);
  	return libmd_MD5End(context, buf);
  }
  
  char *
  MD5File(const char *filename, char *buf)
  {
  	libmd_wrapper(MD5File);
  	return MD5File(filename, buf);
  }
  
  char *
  MD5FileChunk(const char *filename, char *buf, off_t offset, off_t length)
  {
  	libmd_wrapper(MD5FileChunk);
  	return libmd_MD5FileChunk(filename, buf, offset, length);
  }
  
  char *
  MD5Data(const uint8_t *data, size_t len, char *buf)
  {
  	libmd_wrapper(MD5Data);
  	return libmd_MD5Data(data, len, buf);
  }
  

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