Finding the Owner of a File Object in C++

The following example uses the GetSecurityInfo and LookupAccountSid functions to find and print the name of the owner of a file. The file exists in the current working directory on the local server.

#include <stdio.h>
#include <windows.h>
#include <tchar.h>
#include "accctrl.h"
#include "aclapi.h"
#pragma comment(lib, "advapi32.lib")

int main(void)
{
DWORD dwRtnCode = 0;
PSID pSidOwner = NULL;
BOOL bRtnBool = TRUE;
LPTSTR AcctName = NULL;
LPTSTR DomainName = NULL;
DWORD dwAcctName = 1, dwDomainName = 1;
SID_NAME_USE eUse = SidTypeUnknown;
HANDLE hFile;
PSECURITY_DESCRIPTOR pSD = NULL;


// Get the handle of the file object.
hFile = CreateFile(
 TEXT("myfile.txt"),
 GENERIC_READ,
 FILE_SHARE_READ,
 NULL,
 OPEN_EXISTING,
 FILE_ATTRIBUTE_NORMAL,
 NULL);

// Check GetLastError for CreateFile error code.
if (hFile == INVALID_HANDLE_VALUE) {
 DWORD dwErrorCode = 0;

 dwErrorCode = GetLastError();
 _tprintf(TEXT("CreateFile error = %d\n"), dwErrorCode);
 return -1;
}



// Get the owner SID of the file.
dwRtnCode = GetSecurityInfo(
 hFile,
 SE_FILE_OBJECT,
 OWNER_SECURITY_INFORMATION,
 &pSidOwner,
 NULL,
 NULL,
 NULL,
 &pSD);

// Check GetLastError for GetSecurityInfo error condition.
if (dwRtnCode != ERROR_SUCCESS) {
 DWORD dwErrorCode = 0;

 dwErrorCode = GetLastError();
 _tprintf(TEXT("GetSecurityInfo error = %d\n"), dwErrorCode);
 return -1;
}

// First call to LookupAccountSid to get the buffer sizes.
bRtnBool = LookupAccountSid(
 NULL, // local computer
 pSidOwner,
 AcctName,
 (LPDWORD)&dwAcctName,
 DomainName,
 (LPDWORD)&dwDomainName,
 &eUse);

// Reallocate memory for the buffers.
AcctName = (LPTSTR)GlobalAlloc(
 GMEM_FIXED,
 dwAcctName * sizeof(wchar_t));

// Check GetLastError for GlobalAlloc error condition.
if (AcctName == NULL) {
 DWORD dwErrorCode = 0;

 dwErrorCode = GetLastError();
 _tprintf(TEXT("GlobalAlloc error = %d\n"), dwErrorCode);
 return -1;
}

 DomainName = (LPTSTR)GlobalAlloc(
 GMEM_FIXED,
 dwDomainName * sizeof(wchar_t));

 // Check GetLastError for GlobalAlloc error condition.
 if (DomainName == NULL) {
 DWORD dwErrorCode = 0;

 dwErrorCode = GetLastError();
 _tprintf(TEXT("GlobalAlloc error = %d\n"), dwErrorCode);
 return -1;

 }

 // Second call to LookupAccountSid to get the account name.
 bRtnBool = LookupAccountSid(
 NULL, // name of local or remote computer
 pSidOwner, // security identifier
 AcctName, // account name buffer
 (LPDWORD)&dwAcctName, // size of account name buffer 
 DomainName, // domain name
 (LPDWORD)&dwDomainName, // size of domain name buffer
 &eUse); // SID type

 // Check GetLastError for LookupAccountSid error condition.
 if (bRtnBool == FALSE) {
 DWORD dwErrorCode = 0;

 dwErrorCode = GetLastError();

 if (dwErrorCode == ERROR_NONE_MAPPED)
 _tprintf(TEXT
 ("Account owner not found for specified SID.\n"));
 else 
 _tprintf(TEXT("Error in LookupAccountSid.\n"));
 return -1;

 } else if (bRtnBool == TRUE) 

 // Print the account name.
 _tprintf(TEXT("Account owner = %s\n"), AcctName);

 return 0;
}