www.pudn.com > snmp.rar > snmpapi.c

/*++ 
 
Copyright (c) 1992-1997  Microsoft Corporation 
 
Module Name: 
 
    snmpapi.c 
 
Abstract: 
 
    Contains entry point for SNMPAPI.DLL. 
 
Environment: 
 
    User Mode - Win32 
 
Revision History: 
 
--*/ 
 
/////////////////////////////////////////////////////////////////////////////// 
//                                                                           // 
// Include files                                                             // 
//                                                                           // 
/////////////////////////////////////////////////////////////////////////////// 
 
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include "ntfuncs.h" 
 
 
/////////////////////////////////////////////////////////////////////////////// 
//                                                                           // 
// Global Variables                                                          // 
//                                                                           // 
/////////////////////////////////////////////////////////////////////////////// 
 
HMODULE g_hNtDll = NULL; 
DWORD g_dwPlatformId = 0; 
AsnObjectIdentifier * g_pEnterpriseOid = NULL; 
PFNRTLGETNTPRODUCTTYPE g_pfnRtlGetNtProductType = NULL;   
PFNNTQUERYSYSTEMINFORMATION g_pfnNtQuerySystemInformation = NULL; 
PFNRTLEXTENDEDLARGEINTEGERDIVIDE g_pfnRtlExtendedLargeIntegerDivide = NULL; 
 
 
/////////////////////////////////////////////////////////////////////////////// 
//                                                                           // 
// Private Variables                                                         // 
//                                                                           // 
/////////////////////////////////////////////////////////////////////////////// 
 
static UINT idsWindowsNTWorkstation[] = {1,3,6,1,4,1,311,1,1,3,1,1}; 
static UINT idsWindowsNTServer[]      = {1,3,6,1,4,1,311,1,1,3,1,2}; 
static UINT idsWindowsNTDC[]          = {1,3,6,1,4,1,311,1,1,3,1,3}; 
static UINT idsWindows[]              = {1,3,6,1,4,1,311,1,1,3,2}; 
 
static AsnObjectIdentifier oidWindowsNTWorkstation = {  
    sizeof(idsWindowsNTWorkstation)/sizeof(UINT),  
    idsWindowsNTWorkstation  
    }; 
 
static AsnObjectIdentifier oidWindowsNTServer = {  
    sizeof(idsWindowsNTServer)/sizeof(UINT),  
    idsWindowsNTServer  
    }; 
 
static AsnObjectIdentifier oidWindowsNTDC = {  
    sizeof(idsWindowsNTDC)/sizeof(UINT),  
    idsWindowsNTDC  
    }; 
 
static AsnObjectIdentifier oidWindows = {  
    sizeof(idsWindows)/sizeof(UINT),  
    idsWindows  
    }; 
 
 
/////////////////////////////////////////////////////////////////////////////// 
//                                                                           // 
// Private Procedures                                                        // 
//                                                                           // 
/////////////////////////////////////////////////////////////////////////////// 
 
BOOL 
LoadNtDll( 
    ) 
 
/*++ 
 
Routine Description: 
 
    Loads additional library used for NT-specific calls. 
 
Arguments: 
 
    None. 
 
Return Values: 
 
    Returns true if successful.  
 
--*/ 
 
{ 
    BOOL fOk = FALSE; 
 
    // attempt to load ntdll.dll 
    g_hNtDll = LoadLibrary(TEXT("ntdll.dll")); 
                            
    // validate handle                             
    if (g_hNtDll != NULL) {  
         
        // load api to help determine enterprise oid 
        g_pfnRtlGetNtProductType = (PFNRTLGETNTPRODUCTTYPE) 
            GetProcAddress( 
                g_hNtDll, 
                "RtlGetNtProductType" 
                ); 
             
         
        // load api to help determine system uptime 
        g_pfnNtQuerySystemInformation = (PFNNTQUERYSYSTEMINFORMATION) 
            GetProcAddress( 
                g_hNtDll, 
                "NtQuerySystemInformation" 
                ); 
 
        // load api to help determine system uptime 
        g_pfnRtlExtendedLargeIntegerDivide = (PFNRTLEXTENDEDLARGEINTEGERDIVIDE) 
            GetProcAddress( 
                g_hNtDll, 
                "RtlExtendedLargeIntegerDivide" 
                ); 
 
        // validate each function pointer 
        fOk = ((g_pfnRtlGetNtProductType != NULL) && 
               (g_pfnNtQuerySystemInformation != NULL) && 
               (g_pfnRtlExtendedLargeIntegerDivide != NULL)); 
    } 
 
    return fOk; 
} 
 
 
BOOL 
UnloadNtDll( 
    ) 
 
/*++ 
 
Routine Description: 
 
    Unloads additional library used for NT-specific calls. 
 
Arguments: 
 
    None. 
 
Return Values: 
 
    Returns true if successful.  
 
--*/ 
 
{ 
    BOOL fOk = TRUE; 
 
    // validate handle 
    if (g_hNtDll != NULL) { 
 
        // unload library  
        fOk = FreeLibrary(g_hNtDll); 
 
        // re-initialize 
        g_hNtDll = NULL; 
    } 
 
    return fOk; 
} 
 
 
BOOL 
InitializeEnterpriseOID( 
    ) 
 
/*++ 
 
Routine Description: 
 
    Determines the default enterprise object identifier. 
 
Arguments: 
 
    None. 
 
Return Values: 
 
    Returns true if successful.  
 
--*/ 
 
{ 
    NT_PRODUCT_TYPE NtProductType; 
 
    // default to generic oid 
    g_pEnterpriseOid = &oidWindows; 
 
    // check to see if the platform is winnt 
    if (g_dwPlatformId == VER_PLATFORM_WIN32_NT) { 
 
        // assume this is just a workstation         
        g_pEnterpriseOid = &oidWindowsNTWorkstation; 
 
        // validate global data 
        if ((g_hNtDll != NULL) && 
            (g_pfnRtlGetNtProductType != NULL)) { 
             
            // let the system determine product type 
            (*g_pfnRtlGetNtProductType)(&NtProductType); 
 
            // point to the correct enterprise oid 
            if (NtProductType == NtProductServer) { 
 
                // this is a stand-alone server 
                g_pEnterpriseOid = &oidWindowsNTServer; 
 
            } else if (NtProductType == NtProductLanManNt) { 
 
                // this is a PDC or a BDC 
                g_pEnterpriseOid = &oidWindowsNTDC; 
            } 
        } 
    } 
 
    SNMPDBG(( 
        SNMP_LOG_TRACE,  
        "SNMP: INIT: enterprise is %s.\n",  
        SnmpUtilOidToA(g_pEnterpriseOid) 
        )); 
 
    return TRUE; 
} 
 
 
/////////////////////////////////////////////////////////////////////////////// 
//                                                                           // 
// Public Procedures                                                         // 
//                                                                           // 
/////////////////////////////////////////////////////////////////////////////// 
 
BOOLEAN 
InitializeDLL( 
    PVOID  DllHandle, 
    ULONG  Reason, 
    LPVOID lpReserved  
    ) 
 
/*++ 
 
Routine Description: 
 
    Dll entry point. 
 
Arguments: 
 
    Same as DllMain. 
 
Return Values: 
 
    Returns true if successful.  
 
--*/ 
 
{ 
    // check if new process attaching 
    if (Reason == DLL_PROCESS_ATTACH) {  
 
        OSVERSIONINFO osInfo;     
 
        // initialize os info structure 
        osInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO); 
 
        // gather os info 
        GetVersionEx(&osInfo); 
 
        // save platform id for later use 
        g_dwPlatformId = osInfo.dwPlatformId; 
 
        // check to see if platform is windows nt 
        if (g_dwPlatformId == VER_PLATFORM_WIN32_NT) { 
 
            // more to do 
            LoadNtDll(); 
        } 
 
        // initialize enterprise 
        InitializeEnterpriseOID(); 
 
        // turn off thread attach messages 
        DisableThreadLibraryCalls(DllHandle); 
 
    // check if new process detaching 
    } else if (Reason == DLL_PROCESS_DETACH) { 
 
        // check to see if platform is windows nt 
        if (g_dwPlatformId == VER_PLATFORM_WIN32_NT) { 
 
            // more to do 
            UnloadNtDll(); 
        } 
    } 
 
    return TRUE; 
}