Leaked source code of windows server 2003
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/*++
Copyright (c) 1992-1999 Microsoft Corporation
Module Name:
regthrd.c
Abstract:
Contains routines for thread listening to registry changes.
Environment:
User Mode - Win32
Revision History:
Rajat Goel -- 24 Feb 1999
- Creation
--*/
///////////////////////////////////////////////////////////////////////////////
// //
// Include files //
// //
///////////////////////////////////////////////////////////////////////////////
#include "globals.h"
#include "contexts.h"
#include "regions.h"
#include "snmpmgrs.h"
#include "trapmgrs.h"
#include "trapthrd.h"
#include "network.h"
#include "varbinds.h"
#include "snmpmgmt.h"
#include "registry.h"
#include <stdio.h>
///////////////////////////////////////////////////////////////////////////////
// //
// Private procedures //
// //
///////////////////////////////////////////////////////////////////////////////
DWORD
ProcessSubagentChanges(
)
/*++
Routine Description:
Procedure for checking for any changes in the Extension Agents parameter in
the registry
Arguments:
Return Values:
Returns true if successful.
--*/
{
DWORD retval;
DWORD cnt;
HKEY hExAgentsKey = NULL;
// Open the ..SNMP\Parameters\ExtensionAgents key
retval = RegOpenKeyEx(
HKEY_LOCAL_MACHINE,
REG_KEY_EXTENSION_AGENTS,
0,
KEY_READ,
&hExAgentsKey
);
cnt = 0;
if (retval != ERROR_SUCCESS)
{
LPTSTR pszKey = REG_KEY_EXTENSION_AGENTS;
ReportSnmpEvent(
SNMP_EVENT_INVALID_REGISTRY_KEY,
1,
&pszKey,
retval);
return retval;
}
while (retval == ERROR_SUCCESS)
{
DWORD dwNameSize;
DWORD dwValueSize;
DWORD dwValueType;
DWORD dwPathSize;
HKEY hAgentKey = NULL;
TCHAR szName[MAX_PATH];
TCHAR szValue[MAX_PATH];
CHAR szPath[MAX_PATH];
CHAR szExpPath[MAX_PATH];
PSUBAGENT_LIST_ENTRY pSLE = NULL;
dwNameSize = sizeof(szName) / sizeof(szName[0]); // size in number of TCHARs
dwValueSize = sizeof(szValue); // size in number of bytes
dwPathSize = sizeof(szPath);
// Retrieve the registry path for the Extension Agent DLL key
retval = RegEnumValue(
hExAgentsKey,
cnt,
szName,
&dwNameSize,
NULL,
&dwValueType,
(LPBYTE)szValue,
&dwValueSize
);
// if failed to Enum the registry value, this is serious enough to break the loop
if (retval != ERROR_SUCCESS)
break;
if (dwValueType != REG_SZ)
{
// invalid value type, skip
cnt++;
continue;
}
// Open the registry key for the current extension agent
if (RegOpenKeyEx(
HKEY_LOCAL_MACHINE,
szValue,
0,
KEY_READ,
&hAgentKey) == ERROR_SUCCESS)
{
// get the full pathname of the extension agent DLL
if (RegQueryValueExA(
hAgentKey,
REG_VALUE_SUBAGENT_PATH,
NULL,
&dwValueType,
szPath,
&dwPathSize
) == ERROR_SUCCESS &&
(dwValueType == REG_EXPAND_SZ || dwValueType == REG_SZ))
{
DWORD dwRet = 0;
// Expand path
// If the function succeeds, the return value is the number of
// TCHARs stored in the destination buffer, including the
// terminating null character. If the destination buffer is too
// small to hold the expanded string, the return value is the
// required buffer size, in TCHARs.
// If the function fails, the return value is zero. To get
// extended error information, call GetLastError.
dwRet = ExpandEnvironmentStringsA(
szPath,
szExpPath,
sizeof(szExpPath)/sizeof(szExpPath[0]));
if ((dwRet != 0) && (dwRet <= sizeof(szExpPath)/sizeof(szExpPath[0])))
{
// Check if the DLL has already been loaded. If it has,
// mark it. If not load it.
if (FindSubagent(&pSLE, szExpPath))
{
// If this extension agent already exists in the list,
// mark it such that it is not removed further
pSLE->uchFlags |= FLG_SLE_KEEP;
}
else
{
// This is a new DLL, add it to the list and mark it to be kept
// while looking for the extension agents to be removed
if (!AddSubagentByDll(szExpPath, FLG_SLE_KEEP))
{
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: SVC: unable to load extension agent '%s'.\n",
szExpPath
));
}
}
}
else
{
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: SVC: unable to expand extension agent path '%s'.\n",
szPath
));
}
}
else
{
// we couldn't open the registry key which provides the full path to the DLL.
// report the error but don't break the loop as there might be more subagents to handle
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: SVC: unable to retrieve extension agent '%s' value.\n",
REG_VALUE_SUBAGENT_PATH
));
}
RegCloseKey(hAgentKey);
}
else
{
LPTSTR pSzValue = szValue;
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: SVC: unable to open extension agent %s key.\n", szValue
));
ReportSnmpEvent(
SNMP_EVENT_INVALID_EXTENSION_AGENT_KEY,
1,
&pSzValue,
retval);
}
cnt++;
}
// Go through the list of subagents. Unload any DLL's that were not marked
// in the previous loop
{
PLIST_ENTRY pLE;
PSUBAGENT_LIST_ENTRY pSLE;
pLE = g_Subagents.Flink;
while (pLE != &g_Subagents)
{
pSLE = CONTAINING_RECORD(pLE, SUBAGENT_LIST_ENTRY, Link);
if (!(pSLE->uchFlags & FLG_SLE_KEEP))
{
RemoveEntryList(&(pSLE->Link));
pLE = pLE->Flink;
FreeSLE(pSLE);
continue;
}
else
{
// reset the flag for next updates
pSLE->uchFlags ^= FLG_SLE_KEEP;
}
pLE = pLE->Flink;
}
}
if (retval == ERROR_NO_MORE_ITEMS)
retval = ERROR_SUCCESS;
if (hExAgentsKey != NULL)
RegCloseKey(hExAgentsKey);
return retval;
}
///////////////////////////////////////////////////////////////////////////////
// //
// Public procedures //
// //
///////////////////////////////////////////////////////////////////////////////
DWORD
ProcessRegistryMessage(
PVOID pParam
)
/*++
Routine Description:
Thread procedure for processing Registry Changes
Arguments:
pParam - unused.
Return Values:
Returns true if successful.
--*/
{
DWORD retval = ERROR_SUCCESS;
do
{
DWORD evntIndex;
BOOL bEvntSetOk;
// Wait for registry change or Main thread termination
evntIndex = WaitOnRegNotification();
// for one change into the registry several notifications occur (key renaming, value addition,
// value change, etc). In order to avoid useless (and counterproductive) notifications, wait
// here for half of SHUTDOWN_WAIT_HINT.
Sleep(SHUTDOWN_WAIT_HINT/2);
// first thing to do is to re initialize the registry notifiers
// otherwise we might miss some changes
InitRegistryNotifiers();
if (evntIndex == WAIT_FAILED)
{
retval = GetLastError();
break;
}
if (evntIndex == WAIT_OBJECT_0)
{
// termination was signaled
SNMPDBG((
SNMP_LOG_TRACE,
"SNMP: SVC: shutting down the registry listener thread.\n"
));
break;
}
//
// unload and reload the registry parameters
//
// Used in ProcessSnmpMessages->RecvCompletionRoutine
EnterCriticalSection(&g_RegCriticalSectionA);
// Used in ProcessSubagentEvents
EnterCriticalSection(&g_RegCriticalSectionB);
// Used in GenerateTrap
EnterCriticalSection(&g_RegCriticalSectionC);
UnloadPermittedManagers();
UnloadTrapDestinations();
UnloadValidCommunities();
UnloadSupportedRegions();
// start reloading the registry with scalar parameters first
// this is needed in order to know how to perform the name resolution
// when loading PermittedManagers and TrapDestinations.
LoadScalarParameters();
// Check for subagent changes (extension agent dll's)
if (ProcessSubagentChanges() != ERROR_SUCCESS)
SNMPDBG((
SNMP_LOG_TRACE,
"SNMP: SVC: an error occured while trying to track registry subagent changes.\n"
));
LoadSupportedRegions();
LoadPermittedManagers(FALSE);
LoadTrapDestinations(FALSE);
// don't direct dynamic update for the ValidCommunities at this point!
// if a REG_SZ entry occurs at this time, then it should be left as it is.
LoadValidCommunities(FALSE);
SetEvent(g_hRegistryEvent);
LeaveCriticalSection(&g_RegCriticalSectionC);
LeaveCriticalSection(&g_RegCriticalSectionB);
LeaveCriticalSection(&g_RegCriticalSectionA);
SNMPDBG((
SNMP_LOG_TRACE,
"SNMP: SVC: a registry change was detected.\n"
));
ReportSnmpEvent(
SNMP_EVENT_CONFIGURATION_UPDATED,
0,
NULL,
0);
} while(retval == ERROR_SUCCESS);
if (retval != ERROR_SUCCESS)
{
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: SVC: ** Failed in listening for registry changes **.\n"
));
// log an event to system log file - SNMP service is going on but will not update on registry changes
ReportSnmpEvent(
SNMP_EVENT_REGNOTIFY_THREAD_FAILED,
0,
NULL,
retval);
}
return retval;
}