Problem - Kevin Tafuro

generator. The code presented here uses the spc_rand_range( ) function from Recipe
11.11. Refer to Chapter 11 for possible implementations of random number generators.
The function SpcMakeTempFile( ) repeatedly generates a random temporary filename
using a cryptographically strong pseudo-random number generator and attempts to
create the file. The generated filename contains an absolute path specification to the
user’s temporary files directory. If successful, the file is created, inheriting access permissions
from that directory, which ordinarily will prevent users other than the
Administrator and the owner from gaining access to it. If SpcMakeTempFile( ) is
unable to create the file, the process begins anew. SpcMakeTempFile( ) will not return
until a file can be successfully created or some kind of fatal error occurs.
As arguments, SpcMakeTempFile( ) requires a preallocated writable buffer and the size
of that buffer in characters. The buffer will contain the filename used to successfully
create the temporary file, and the return value from the function will be a handle to
the open file. If an error occurs, the return value will be INVALID_HANDLE_VALUE, and
GetLastError( ) can be used to obtain more detailed error information.
#include
static LPTSTR lpszFilenameCharacters = TEXT("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ");
static BOOL MakeTempFilename(LPTSTR lpszBuffer, DWORD dwBuffer) {
int i;
DWORD dwCharacterRange, dwTempPathLength;
TCHAR cCharacter;
dwTempPathLength = GetTempPath(dwBuffer, lpszBuffer);
if (!dwTempPathLength) return FALSE;
if (++dwTempPathLength > dwBuffer || dwBuffer - dwTempPathLength < 12) {
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return FALSE;
}
dwCharacterRange = lstrlen(lpszFilenameCharacters) - 1;
for (i = 0; i < 8; i++) {
cCharacter = lpszFilenameCharacters[spc_rand_range(0, dwCharacterRange)];
lpszBuffer[dwTempPathLength++ - 1] = cCharacter;
}
lpszBuffer[dwTempPathLength++ - 1] = '.';
lpszBuffer[dwTempPathLength++ - 1] = 'T';
lpszBuffer[dwTempPathLength++ - 1] = 'M';
lpszBuffer[dwTempPathLength++ - 1] = 'P';
lpszBuffer[dwTempPathLength++ - 1] = 0;
return TRUE;
}
HANDLE SpcMakeTempFile(LPTSTR lpszBuffer, DWORD dwBuffer) {
HANDLE hFile;
do {
Creating Files for Temporary Use | 67
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