Getting system handles

Code:

    #define SystemHandleInformation 0x10

	typedef struct _SYSTEM_HANDLE_INFORMATION {
		ULONG ProcessId;
		UCHAR ObjectTypeNumber;
		UCHAR Flags;
		USHORT Handle;
		PVOID Object;
		ACCESS_MASK GrantedAccess;
	} SYSTEM_HANDLE_INFORMATION, *PSYSTEM_HANDLE_INFORMATION;

	typedef struct _SYSTEM_HANDLE_INFORMATION_EX {
		ULONG NumberOfHandles;
		SYSTEM_HANDLE_INFORMATION Information[1];
	} SYSTEM_HANDLE_INFORMATION_EX, *PSYSTEM_HANDLE_INFORMATION_EX;



	typedef DWORD (WINAPI *PfZwQuerySystemInformation)(int, PBYTE, ULONG, PULONG);

	PfZwQuerySystemInformation MyZwQuerySystemInformation;

	PSYSTEM_HANDLE_INFORMATION_EX pStruct;
	ULONG dimBuffer = sizeof(SYSTEM_HANDLE_INFORMATION); 

	pStruct = (PSYSTEM_HANDLE_INFORMATION_EX)malloc(dimBuffer);

	MyZwQuerySystemInformation = (PfZwQuerySystemInformation)GetProcAddress(GetModuleHandle("ntdll.dll"),"ZwQuerySystemInformation");

#define STATUS_INFO_LENGTH_MISMATCH     0xC0000004L
#define STATUS_BUFFER_OVERFLOW              0x80000005L

	if(STATUS_INFO_LENGTH_MISMATCH == MyZwQuerySystemInformation(SystemHandleInformation, (PBYTE)pStruct, dimBuffer, &dimBuffer)) 
MessageBox(NULL,"STATUS_INFO_LENGTH_MISMATCH","",MB_OK | MB_ICONERROR);
	
else goto QUERY_OK;
 
  // realloc pStruct

    free(pStruct);

	char c[20]; sprintf(c,"0x%x",dimBuffer);MessageBox(NULL,c,"dimBuffer",MB_OK);

	pStruct = (PSYSTEM_HANDLE_INFORMATION_EX)malloc(dimBuffer);

	if(STATUS_INFO_LENGTH_MISMATCH == MyZwQuerySystemInformation(SystemHandleInformation, (PBYTE)pStruct, dimBuffer, &dimBuffer)){
	 MessageBox(NULL,"STATUS_INFO_LENGTH_MISMATCH","",MB_OK | MB_ICONERROR);
	 return;
	} 

QUERY_OK:
// .......

All 3 messages wiil be printed out,and dimBuffer will be 0 after the first call to NtQuerySystemInformation( )

the second call fails because dimBuffer is 0,but shouldn't the first call assign a nonzero value to it???

ok,i found the solution by myself,it works

Code:

	while(STATUS_INFO_LENGTH_MISMATCH == MyZwQuerySystemInformation(SystemHandleInformation, (PBYTE)pStruct, dimBuffer, &dimBuffer)){
	 dimBuffer += 4 * 1024;
     free(pStruct);
	 pStruct = (PSYSTEM_HANDLE_INFORMATION_EX)malloc(dimBuffer);   
	}