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Power CD-ROM!! 7
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POWERCD7.ISO
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exeval_c
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exevalid.c
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C/C++ Source or Header
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1994-07-18
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9KB
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250 lines
/* Source for the .EXE file validation fuction ValidateEXE(), along */
/* with support functions used by ValidateEXE(). To use the .EXE file */
/* Validation system within your program, #include "exevalid.h", and */
/* add exevalid.c to your program's makefile / project file. See */
/* exedemo?.c for an example of how to use ValidateEXE(). When your */
/* program's executable has been built, use the exestamp program to */
/* create a hash stamp before running your program. To customize the */
/* hash code used by this program, simply alter or replace the */
/* UpdateHash() function. */
/* Standard header files. */
#include <stdlib.h>
#include <stdio.h>
/* Our header file. */
#include "exevalid.h"
/* Table used for calculating CRC32s */
unsigned long ulCRC32Table[256] =
{
0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL,
0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L,
0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L,
0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L,
0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL,
0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L,
0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 0xa2677172L,
0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L,
0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L,
0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 0xb8bda50fL,
0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL,
0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL,
0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L,
0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, 0xe10e9818L,
0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL,
0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL,
0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L,
0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL,
0x4369e96aL, 0x346ed9fcL, 0xad678846L, 0xda60b8d0L,
0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, 0xdd0d7cc9L,
0x5005713cL, 0x270241aaL, 0xbe0b1010L, 0xc90c2086L,
0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L,
0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
0xedb88320L, 0x9abfb3b6L, 0x03b6e20cL, 0x74b1d29aL,
0xead54739L, 0x9dd277afL, 0x04db2615L, 0x73dc1683L,
0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L,
0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL,
0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L,
0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, 0x67dd4accL,
0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L,
0xd1bb67f1L, 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, 0x41047a60L,
0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 0x4669be79L,
0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL,
0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L,
0xc2d7ffa7L, 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL,
0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, 0x026d930aL,
0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L,
0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL,
0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, 0x18b74777L,
0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L,
0xa00ae278L, 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L,
0xa7672661L, 0xd06016f7L, 0x4969474dL, 0x3e6e77dbL,
0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L,
0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L,
0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL,
0xb3667a2eL, 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L,
0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 0x2d02ef8dL
};
/* Function : GetFileHash()
*
* Purpose : Calculates the hash code for the specified number of
* bytes beginning at the current position in an open file.
*
* Parameters : pFile - Pointer to an open stream to calculate hash
* value from.
*
* lnBytes - Number of bytes from file to calculate hash
* on.
*
* pnHash - Pointer to a variable of type tHash to store
* hash code in.
*
* Return Value : TRUE on success, FALSE on failure.
*/
BOOL GetFileHash(FILE *pFile, long lnBytes, tHash *pnHash)
{
char *pBuffer;
long lnRead;
/* Initialize hash value. */
*pnHash = 0xffffffffL;
/* Allocate a buffer for file reads. */
pBuffer = (char *)malloc(FILE_BUFFER_SIZE);
/* If allocation failed, return with an error. */
if(pBuffer == NULL)
{
return(FALSE);
}
/* Loop while there are still more bytes to be read from file. */
while(lnBytes > 0)
{
/* Read next segment from file. */
lnRead = fread(pBuffer, sizeof(char),
(size_t)MIN(lnBytes, FILE_BUFFER_SIZE), pFile);
/* If read did not obtain any characters, return with failure. */
if(lnRead == 0)
{
return(FALSE);
}
/* Update hash value with each byte in the buffer */
UpdateHash(pnHash, pBuffer, lnRead);
/* Update number of bytes remaining to be read. */
lnBytes -= lnRead;
}
/* Release memory for buffer. */
free(pBuffer);
/* Return with success. */
return(TRUE);
}
/* Function : UpdateHash()
*
* Purpose : Updates hash code based on passed bytes.
* This implementation uses a CRC32 algorithm to calculate
* the hash code. You can customize the .EXE file validation
* system by using a different algorithm to calculate this
* hash code. If you change this algorithm, be sure to also
* recompile the exestamp utility.
*
* Parameters : pnHash - Pointer to variable where old hash value is
* stored, and where new hash value will be
* stored.
*
* pBuffer - Pointer to buffer containing bytes to be
* used to update hash code.
*
* lnBytes - Number of bytes to validate from buffer.
*
* Return Value : N/A
*/
void UpdateHash(tHash *pnHash, char *pBuffer, long lnBytes)
{
/* Work with local copy of hash value. */
unsigned long nHash = *pnHash;
/* Loop for each byte in the buffer. */
while(lnBytes--)
{
/* Update hash code with this byte. */
nHash = ulCRC32Table[(unsigned char)(nHash ^
(unsigned long)(*pBuffer++))]
^ ((nHash << 8) & 0x00ffffffL);
}
/* Copy hash value back to passed variable. */
*pnHash = nHash;
}
/* Function : ValidateEXE()
*
* Purpose : Determines whether or not an .EXE file contains a
* valid hash code stamp.
*
* Parameters : pszEXEFileName - Filename of .EXE file to validate.
*
* Return Value : One of the following constants:
* kValid - .EXE is valid.
* kInvalid - .EXE is not valid.
* kGeneralFailure - Unable to access file or allocate memory.
*/
eEXEValidResult ValidateEXE(char *pszEXEFileName)
{
FILE *pEXEFile;
tHash nActualFileHash;
tHash nRecordedFileHash;
long lnFileLength;
/* Attempt to open .EXE for read in binary mode. */
pEXEFile = fopen(pszEXEFileName, "rb");
/* If open failed, return with failure. */
if(pEXEFile == NULL)
{
return(kGeneralFailure);
}
/* Determine length of .EXE file. */
fseek(pEXEFile, 0, SEEK_END);
lnFileLength = ftell(pEXEFile);
fseek(pEXEFile, 0, SEEK_SET);
/* Determine actual hash code of file. */
if(!GetFileHash(pEXEFile, lnFileLength - sizeof(tHash), &nActualFileHash))
{
return(kGeneralFailure);
}
/* Read hash code stored in file. */
if(fread(&nRecordedFileHash, sizeof(tHash), 1, pEXEFile) != 1)
{
return(kGeneralFailure);
}
/* Close .EXE file. */
fclose(pEXEFile);
/* File is valid iff recorded hash code and actual hash code are equal. */
if(nRecordedFileHash == nActualFileHash)
{
return(kValid);
}
else
{
return(kInvalid);
}
}