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/* biossums.c --- written by Eike W. */
#include <stdlib.h>
#include <stdio.h>
typedef unsigned char byte;
void check( int value, char* message );
#define LEN_BIOS_DATA 0x10000
#define MAX_OFFSET (LEN_BIOS_DATA - 1)
#define BIOS_OFFSET 0xFFFF
long chksum_bios_get_offset( byte* data, long offset );
byte chksum_bios_calc_value( byte* data, long offset );
byte chksum_bios_get_value( byte* data, long offset );
void chksum_bios_set_value( byte* data, long offset, byte value );
#define _32__LEN 9
#define _32__CHKSUM 10
#define _32__MINHDR 16
long chksum__32__get_offset( byte* data, long offset );
byte chksum__32__calc_value( byte* data, long offset );
byte chksum__32__get_value( byte* data, long offset );
void chksum__32__set_value( byte* data, long offset, byte value );
#define _MP__LEN 8
#define _MP__CHKSUM 10
#define _MP__MINHDR 16
long chksum__mp__get_offset( byte* data, long offset );
byte chksum__mp__calc_value( byte* data, long offset );
byte chksum__mp__get_value( byte* data, long offset );
void chksum__mp__set_value( byte* data, long offset, byte value );
#define PCMP_BASELEN 4
#define PCMP_CHKSUM 7
#define PCMP_EXT_LEN 40
#define PCMP_EXT_CHKSUM 42
#define PCMP_MINHDR 42
long chksum_pcmp_get_offset( byte* data, long offset );
byte chksum_pcmp_calc_value( byte* data, long offset );
byte chksum_pcmp_get_value( byte* data, long offset );
void chksum_pcmp_set_value( byte* data, long offset, byte value );
#define _PIR_LEN 6
#define _PIR_CHKSUM 31
#define _PIR_MINHDR 32
long chksum__pir_get_offset( byte *data, long offset );
byte chksum__pir_calc_value( byte* data, long offset );
byte chksum__pir_get_value( byte* data, long offset );
void chksum__pir_set_value( byte* data, long offset, byte value );
byte bios_data[LEN_BIOS_DATA];
int main( int argc, char* argv[] ) {
FILE* stream;
long offset, tmp_offset;
byte cur_val = 0, new_val = 0;
int hits;
if( argc != 2 ) {
printf( "Error. Need a file-name as an argument.\n" );
exit( EXIT_FAILURE );
}
if(( stream = fopen( argv[1], "rb" )) == NULL ) {
printf( "Error opening %s for reading.\n", argv[1] );
exit( EXIT_FAILURE );
}
if( fread( bios_data, 1, LEN_BIOS_DATA, stream ) < LEN_BIOS_DATA ) {
printf( "Error reading 64KBytes from %s.\n", argv[1] );
fclose( stream );
exit( EXIT_FAILURE );
}
fclose( stream );
hits = 0;
offset = 0L;
while( (tmp_offset = chksum__32__get_offset( bios_data, offset )) != -1L ) {
offset = tmp_offset;
cur_val = chksum__32__get_value( bios_data, offset );
new_val = chksum__32__calc_value( bios_data, offset );
printf( "\n\nPCI-Bios header at: 0x%4lX\n", offset );
printf( "Current checksum: 0x%02X\n", cur_val );
printf( "Calculated checksum: 0x%02X ", new_val );
hits++;
}
if( hits == 1 && cur_val != new_val ) {
printf( "Setting checksum." );
chksum__32__set_value( bios_data, offset, new_val );
}
if( hits >= 2 ) {
printf( "Multiple PCI headers! No checksum set." );
}
if( hits ) {
printf( "\n" );
}
hits = 0;
offset = 0L;
while( (tmp_offset = chksum__mp__get_offset( bios_data, offset )) != -1L ) {
offset = tmp_offset;
cur_val = chksum__mp__get_value( bios_data, offset );
new_val = chksum__mp__calc_value( bios_data, offset );
printf( "\n\nMP header at: 0x%4lX\n", offset );
printf( "Current checksum: 0x%02X\n", cur_val );
printf( "Calculated checksum: 0x%02X ", new_val );
hits++;
}
if( hits == 1 && cur_val != new_val ) {
printf( "Setting checksum." );
chksum__mp__set_value( bios_data, offset, new_val );
}
if( hits >= 2 ) {
printf( "Warning! Multiple MP headers. No checksum set." );
}
if( hits ) {
printf( "\n" );
}
hits = 0;
offset = 0L;
while( (tmp_offset = chksum_pcmp_get_offset( bios_data, offset )) != -1L ) {
offset = tmp_offset;
cur_val = chksum_pcmp_get_value( bios_data, offset );
new_val = chksum_pcmp_calc_value( bios_data, offset );
printf( "\n\nPCMP header at: 0x%4lX\n", offset );
printf( "Current checksum: 0x%02X\n", cur_val );
printf( "Calculated checksum: 0x%02X ", new_val );
hits++;
}
if( hits == 1 && cur_val != new_val ) {
printf( "Setting checksum." );
chksum_pcmp_set_value( bios_data, offset, new_val );
}
if( hits >= 2 ) {
printf( "Warning! Multiple PCMP headers. No checksum set." );
}
if( hits ) {
printf( "\n" );
}
hits = 0;
offset = 0L;
while( (tmp_offset = chksum__pir_get_offset( bios_data, offset )) != -1L ) {
offset = tmp_offset;
cur_val = chksum__pir_get_value( bios_data, offset );
new_val = chksum__pir_calc_value( bios_data, offset );
printf( "\n\n$PIR header at: 0x%4lX\n", offset );
printf( "Current checksum: 0x%02X\n", cur_val );
printf( "Calculated checksum: 0x%02X\n ", new_val );
hits++;
}
if( hits == 1 && cur_val != new_val ) {
printf( "Setting checksum." );
chksum__pir_set_value( bios_data, offset, new_val );
}
if( hits >= 2 ) {
printf( "Warning! Multiple $PIR headers. No checksum set." );
}
if( hits ) {
printf( "\n" );
}
offset = 0L;
offset = chksum_bios_get_offset( bios_data, offset );
cur_val = chksum_bios_get_value( bios_data, offset );
new_val = chksum_bios_calc_value( bios_data, offset );
printf( "\n\nBios checksum at: 0x%4lX\n", offset );
printf( "Current checksum: 0x%02X\n", cur_val );
printf( "Calculated checksum: 0x%02X ", new_val );
if( cur_val != new_val ) {
printf( "Setting checksum." );
chksum_bios_set_value( bios_data, offset, new_val );
}
printf( "\n" );
if(( stream = fopen( argv[1], "wb" )) == NULL ) {
printf( "Error opening %s for writing.\n", argv[1] );
exit( EXIT_FAILURE );
}
if( fwrite( bios_data, 1, LEN_BIOS_DATA, stream ) < LEN_BIOS_DATA ) {
printf( "Error writing 64KBytes to %s.\n", argv[1] );
fclose( stream );
exit( EXIT_FAILURE );
}
fclose( stream );
return( EXIT_SUCCESS );
}
void check( int okay, char* message ) {
if( !okay ) {
printf( "\n\nError. %s.\n", message );
exit( EXIT_FAILURE );
}
}
long chksum_bios_get_offset( byte* data, long offset ) {
return( BIOS_OFFSET );
}
byte chksum_bios_calc_value( byte* data, long offset ) {
int i;
byte sum;
sum = 0;
for( i = 0; i < MAX_OFFSET; i++ ) {
sum = sum + *( data + i );
}
sum = -sum; /* iso ensures -s + s == 0 on unsigned types */
return( sum );
}
byte chksum_bios_get_value( byte* data, long offset ) {
return( *( data + BIOS_OFFSET ) );
}
void chksum_bios_set_value( byte* data, long offset, byte value ) {
*( data + BIOS_OFFSET ) = value;
}
byte chksum__32__calc_value( byte* data, long offset ) {
int i;
int len;
byte sum;
check( offset + _32__MINHDR <= MAX_OFFSET, "_32_ header out of bounds" );
len = *( data + offset + _32__LEN ) << 4;
check( offset + len <= MAX_OFFSET, "_32_ header-length out of bounds" );
sum = 0;
for( i = 0; i < len; i++ ) {
if( i != _32__CHKSUM ) {
sum = sum + *( data + offset + i );
}
}
sum = -sum;
return( sum );
}
long chksum__32__get_offset( byte* data, long offset ) {
long result = -1L;
offset = offset + 0x0F;
offset = offset & ~( 0x0F );
while( offset + 16 < MAX_OFFSET ) {
offset = offset + 16;
if( *( data + offset + 0 ) == '_' && \
*( data + offset + 1 ) == '3' && \
*( data + offset + 2 ) == '2' && \
*( data + offset + 3 ) == '_' ) {
result = offset;
break;
}
}
return( result );
}
byte chksum__32__get_value( byte* data, long offset ) {
check( offset + _32__CHKSUM <= MAX_OFFSET, "PCI-Bios checksum out of bounds" );
return( *( data + offset + _32__CHKSUM ) );
}
void chksum__32__set_value( byte* data, long offset, byte value ) {
check( offset + _32__CHKSUM <= MAX_OFFSET, "PCI-Bios checksum out of bounds" );
*( data + offset + _32__CHKSUM ) = value;
}
byte chksum__mp__calc_value( byte* data, long offset ) {
int i;
int len;
byte sum;
check( offset + _MP__MINHDR <= MAX_OFFSET, "_MP_ header out of bounds" );
len = *( data + offset + _MP__LEN ) << 4;
check( offset + len <= MAX_OFFSET, "_MP_ header-length out of bounds" );
sum = 0;
for( i = 0; i < len; i++ ) {
if( i != _MP__CHKSUM ) {
sum = sum + *( data + offset + i );
}
}
sum = -sum;
return( sum );
}
long chksum__mp__get_offset( byte* data, long offset ) {
long result = -1L;
offset = offset + 0x0F;
offset = offset & ~( 0x0F );
while( offset + 16 < MAX_OFFSET ) {
offset = offset + 16;
if( *( data + offset + 0 ) == '_' && \
*( data + offset + 1 ) == 'M' && \
*( data + offset + 2 ) == 'P' && \
*( data + offset + 3 ) == '_' ) {
result = offset;
break;
}
}
return( result );
}
byte chksum__mp__get_value( byte* data, long offset ) {
check( offset + _MP__CHKSUM <= MAX_OFFSET, "MP checksum out of bounds" );
return( *( data + offset + _MP__CHKSUM ) );
}
void chksum__mp__set_value( byte* data, long offset, byte value ) {
check( offset + _MP__CHKSUM <= MAX_OFFSET, "MP checksum out of bounds" );
*( data + offset + _MP__CHKSUM ) = value;
}
byte chksum_pcmp_calc_value( byte* data, long offset ) {
int i;
int len;
byte sum;
check( offset + PCMP_MINHDR <= MAX_OFFSET, "PCMP header out of bounds" );
len = *( data + offset + PCMP_BASELEN ) + \
( *( data + offset + PCMP_BASELEN + 1 ) << 8 );
check( offset + len <= MAX_OFFSET, "PCMP header-length out of bounds" );
if( *( data + offset + PCMP_EXT_LEN ) | \
*( data + offset + PCMP_EXT_LEN + 1 ) | \
*( data + offset + PCMP_EXT_CHKSUM ) ) {
check( 0, "PCMP header indicates extended tables (unsupported)" );
}
sum = 0;
for( i = 0; i < len; i++ ) {
if( i != PCMP_CHKSUM ) {
sum = sum + *( data + offset + i );
}
}
sum = -sum;
return( sum );
}
long chksum_pcmp_get_offset( byte* data, long offset ) {
long result = -1L;
offset = offset + 0x0F;
offset = offset & ~( 0x0F );
while( offset + 16 < MAX_OFFSET ) {
offset = offset + 16;
if( *( data + offset + 0 ) == 'P' && \
*( data + offset + 1 ) == 'C' && \
*( data + offset + 2 ) == 'M' && \
*( data + offset + 3 ) == 'P' ) {
result = offset;
break;
}
}
return( result );
}
byte chksum_pcmp_get_value( byte* data, long offset ) {
check( offset + PCMP_CHKSUM <= MAX_OFFSET, "PCMP checksum out of bounds" );
return( *( data + offset + PCMP_CHKSUM ) );
}
void chksum_pcmp_set_value( byte* data, long offset, byte value ) {
check( offset + PCMP_CHKSUM <= MAX_OFFSET, "PCMP checksum out of bounds" );
*( data + offset + PCMP_CHKSUM ) = value;
}
byte chksum__pir_calc_value( byte* data, long offset ) {
int i;
int len;
byte sum;
check( offset + _PIR_MINHDR <= MAX_OFFSET, "$PIR header out of bounds" );
len = *( data + offset + _PIR_LEN ) + \
( *( data + offset + _PIR_LEN + 1 ) << 8 );
check( offset + len <= MAX_OFFSET, "$PIR header-length out of bounds" );
sum = 0;
for( i = 0; i < len; i++ ) {
if( i != _PIR_CHKSUM ) {
sum = sum + *( data + offset + i );
}
}
sum = -sum;
return( sum );
}
long chksum__pir_get_offset( byte* data, long offset ) {
long result = -1L;
offset = offset + 0x0F;
offset = offset & ~( 0x0F );
while( offset + 16 < MAX_OFFSET ) {
offset = offset + 16;
if( *( data + offset + 0 ) == '$' && \
*( data + offset + 1 ) == 'P' && \
*( data + offset + 2 ) == 'I' && \
*( data + offset + 3 ) == 'R' ) {
result = offset;
break;
}
}
return( result );
}
byte chksum__pir_get_value( byte* data, long offset ) {
check( offset + _PIR_CHKSUM <= MAX_OFFSET, "$PIR checksum out of bounds" );
return( *( data + offset + _PIR_CHKSUM ) );
}
void chksum__pir_set_value( byte* data, long offset, byte value ) {
check( offset + _PIR_CHKSUM <= MAX_OFFSET, "$PIR checksum out of bounds" );
*( data + offset + _PIR_CHKSUM ) = value;
}
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