Mega Code Archive
How to fetch the portable executables checksum using ImageHelp
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Title: How to fetch the portable executables checksum using ImageHelp
program exeChecksum;
uses Windows, ImageHlp;
{$APPTYPE CONSOLE}
function ComputePEChecksum(FileName: string): DWORD;
var
h, hMap: Cardinal;
pMem: Pointer;
headersum, checksum, fsizehigh, fsizelow: DWORD;
nth: PImageNtHeaders;
Label
cleanup;
begin
pMem := nil;
Result := 0;
headersum := 0;
checksum := 0;
h := Windows.CreateFile(PChar(FileName), GENERIC_READ, FILE_SHARE_READ,
nil, OPEN_EXISTING, 0, 0);
if (h = INVALID_HANDLE_VALUE) then
Exit;
fsizelow := Windows.GetFileSize(h, Pointer(@fsizehigh));
hMap := Windows.CreateFileMapping(h, nil, PAGE_READONLY, fsizeHigh, fsizeLow, nil);
if (hMap = 0) then
goto cleanup;
pMem := Windows.MapViewOfFile(hMap, FILE_MAP_READ, 0, 0, 0);
if (pMem = nil) then
goto cleanup;
nth := CheckSumMappedFile(pMem, fsizeLow, @headersum, @checksum);
if (nth = nil) then
checksum := 0;
cleanup:
if (pMem nil) then
Windows.UnmapViewOfFile(pMem);
if (hMap 0) then
Windows.CloseHandle(hMap);
if (h 0) then
Windows.CloseHandle(h);
Result := checksum;
end;
var
x1, x2: DWORD;
begin
x1 := ComputePEChecksum('c:\1.exe'); // original filename
x2 := ComputePEChecksum('c:\2.exe');
// original filename but has a string in it lightly modified
WriteLn('Checksum 1: ', x1, #13#10'Checksum 2: ', x2);
end.
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