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/*
* shacmp.cpp
*
* Copyright (C) 1998, 2009
* Paul E. Jones <paulej@packetizer.com>
* All Rights Reserved
*
*****************************************************************************
* $Id: shacmp.cpp 12 2009-06-22 19:34:25Z paulej $
*****************************************************************************
*
* Description:
* This utility will compare two files by producing a message digest
* for each file using the Secure Hashing Algorithm and comparing
* the message digests. This function will return 0 if they
* compare or 1 if they do not or if there is an error.
* Errors result in a return code higher than 1.
*
* Portability Issues:
* none.
*
*/
#include <stdio.h>
#include <string.h>
#include "sha1.h"
/*
* Return codes
*/
#define SHA1_COMPARE 0
#define SHA1_NO_COMPARE 1
#define SHA1_USAGE_ERROR 2
#define SHA1_FILE_ERROR 3
/*
* Function prototype
*/
void usage();
/*
* main
*
* Description:
* This is the entry point for the program
*
* Parameters:
* argc: [in]
* This is the count of arguments in the argv array
* argv: [in]
* This is an array of filenames for which to compute message digests
*
* Returns:
* Nothing.
*
* Comments:
*
*/
int main(int argc, char *argv[])
{
SHA1 sha; // SHA-1 class
FILE *fp; // File pointer for reading files
char c; // Character read from file
unsigned message_digest[2][5]; // Message digest for files
int i; // Counter
bool message_match; // Message digest match flag
int returncode;
/*
* If we have two arguments, we will assume they are filenames. If
* we do not have to arguments, call usage() and exit.
*/
if (argc != 3)
{
usage();
return SHA1_USAGE_ERROR;
}
/*
* Get the message digests for each file
*/
for(i = 1; i <= 2; i++)
{
sha.Reset();
if (!(fp = fopen(argv[i],"rb")))
{
fprintf(stderr, "sha: unable to open file %s\n", argv[i]);
return SHA1_FILE_ERROR;
}
c = fgetc(fp);
while(!feof(fp))
{
sha.Input(c);
c = fgetc(fp);
}
fclose(fp);
if (!sha.Result(message_digest[i-1]))
{
fprintf(stderr,"shacmp: could not compute message digest for %s\n",
argv[i]);
return SHA1_FILE_ERROR;
}
}
/*
* Compare the message digest values
*/
message_match = true;
for(i = 0; i < 5; i++)
{
if (message_digest[0][i] != message_digest[1][i])
{
message_match = false;
break;
}
}
if (message_match)
{
printf("Fingerprints match:\n");
returncode = SHA1_COMPARE;
}
else
{
printf("Fingerprints do not match:\n");
returncode = SHA1_NO_COMPARE;
}
printf( "\t%08X %08X %08X %08X %08X\n",
message_digest[0][0],
message_digest[0][1],
message_digest[0][2],
message_digest[0][3],
message_digest[0][4]);
printf( "\t%08X %08X %08X %08X %08X\n",
message_digest[1][0],
message_digest[1][1],
message_digest[1][2],
message_digest[1][3],
message_digest[1][4]);
return returncode;
}
/*
* usage
*
* Description:
* This function will display program usage information to the user.
*
* Parameters:
* None.
*
* Returns:
* Nothing.
*
* Comments:
*
*/
void usage()
{
printf("usage: shacmp <file> <file>\n");
printf("\tThis program will compare the message digests (fingerprints)\n");
printf("\tfor two files using the Secure Hashing Algorithm (SHA-1).\n");
}
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