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windows-nt/Source/XPSP1/NT/ds/netapi/svcdlls/msgsvc/server/threads.c

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/*++
Copyright (c) 1991 Microsoft Corporation
Module Name:
threads.c
Abstract:
This file contains routines that manage access to a database of
worker thread handles and a database containing the current messenger
status (used to report status to the Service Controller). Access to
these two databases is controled via a Critical Section.
Functions for managing worker threads:
MsgThreadManagerInit
MsgThreadCloseAll
Routines for managing _access to the status information and reporting:
MsgStatusInit
MsgBeginForcedShutdown
MsgStatusUpdate
GetMsgrState
Author:
Dan Lafferty (danl) 17-Jul-1991
Environment:
User Mode -Win32
Notes:
These functions must be used carefully in order to be effective in
shutting the messenger threads down nicely if the shutdown happens
to occur during Messenger Initialization. This note explains when
each function is to be called.
MsgThreadManagerInit
This function must be called early on in the initialization process.
It should be called before NetRegisterCtrlDispatcher. This way,
it is impossible for an UNINSTALL request to be received prior to
initializing the Critical Section and the Messenger State.
Revision History:
15-Dec-1998 jschwart
Eliminated MsgThreadManagerEnd. The DLL is no longer unloaded by
services.exe, so deleting the critical section can create a race
condition (stop service, new service starts and calls init, first
thread deletes critsec, first thread tries to enter critsec and AVs)
03-Nov-1992 Danl
Changed status reporting so that we only accept STOP controls if
the service is in the RUNNING state.
18-Feb-1992 RitaW
Convert to Win32 service control APIs.
02-Oct-1991 JohnRo
Work toward UNICODE.
17-Jul-1991 danl
created
--*/
//
// Includes
//
#include "msrv.h"
#include <string.h> // strlen
#include <winsvc.h> // SERVICE_STATUS
#include <netlib.h> // UNUSED Macro
#include "msgdbg.h" // MSG_LOG
#include "msgdata.h"
//
// Global Data
//
RTL_RESOURCE g_StateResource;
SERVICE_STATUS MsgrStatus;
DWORD HintCount;
DWORD MsgrUninstallCode; // reason for uninstalling
BOOL g_fResourceCreated;
DWORD MsgrState;
DWORD
MsgThreadManagerInit(
VOID
)
/*++
Routine Description:
Initializes the critical section that is used to guard access to the
thread and status database. Note that this critsec is created and
never deleted (OK since the DLL is never unloaded by services.exe) to
fix synchronization problems with stopping/restarting the service.
Arguments:
none
Return Value:
NO_ERROR on success, ERROR_NOT_ENOUGH_MEMORY if the init fails
Note:
--*/
{
DWORD dwError = NO_ERROR;
NTSTATUS status;
if (!g_fResourceCreated)
{
status = MsgInitResource(&g_StateResource);
if (NT_SUCCESS(status))
{
g_fResourceCreated = TRUE;
}
else
{
MSG_LOG1(ERROR,
"MsgThreadManagerInit: MsgInitResource failed %#x\n",
status);
dwError = ERROR_NOT_ENOUGH_MEMORY;
}
}
return dwError;
}
VOID
MsgThreadCloseAll(
VOID
)
/*++
Routine Description:
Closes all handles stored in the table of worker thread handles.
Arguments:
none
Return Value:
none
Note:
--*/
{
RtlAcquireResourceExclusive(&g_StateResource, TRUE);
MsgrState = STOPPING;
RtlReleaseResource(&g_StateResource);
}
VOID
MsgStatusInit(VOID)
/*++
Routine Description:
Initializes the status database.
Arguments:
none.
Return Value:
none.
Note:
--*/
{
RtlAcquireResourceExclusive(&g_StateResource, TRUE);
MsgrState = STARTING;
HintCount = 1;
MsgrUninstallCode = 0;
MsgrStatus.dwServiceType = SERVICE_WIN32;
MsgrStatus.dwCurrentState = SERVICE_START_PENDING;
MsgrStatus.dwControlsAccepted = 0;
MsgrStatus.dwCheckPoint = HintCount;
MsgrStatus.dwWaitHint = 20000; // 20 seconds
SET_SERVICE_EXITCODE(
NO_ERROR,
MsgrStatus.dwWin32ExitCode,
MsgrStatus.dwServiceSpecificExitCode
);
RtlReleaseResource(&g_StateResource);
return;
}
DWORD
MsgBeginForcedShutdown(
IN BOOL PendingCode,
IN DWORD ExitCode
)
/*++
Routine Description:
This function is called to set the appropriate status when a shutdown
is to occur due to an error in the Messenger. NOTE: if a shutdown is
based on a request from the Service Controller, MsgStatusUpdate is
called instead.
On a PENDING call, this routine will also wake up all messenger
threads so that they will also shut down.
Arguments:
PendingCode - Indicates if the Shutdown is immediate or pending. If
PENDING, the shutdown will take some time, so a pending status is
sent to the ServiceController.
ExitCode - Indicates the reason for the shutdown.
Return Value:
CurrentState - Contains the current state that the messenger is in
upon exit from this routine. In this case it will be STOPPED
if the PendingCode is PENDING, or STOPPING if the PendingCode
is IMMEDIATE.
Note:
--*/
{
NET_API_STATUS status;
RtlAcquireResourceExclusive(&g_StateResource, TRUE);
//
// See if the messenger is already stopping for some reason.
// It could be that the ControlHandler thread received a control to
// stop the messenger just as we decided to stop ourselves.
//
if ((MsgrState != STOPPING) && (MsgrState != STOPPED)) {
if (PendingCode == PENDING) {
MsgrStatus.dwCurrentState = SERVICE_STOP_PENDING;
MsgrState = STOPPING;
}
else {
//
// The shutdown is to take immediate effect.
//
MsgrStatus.dwCurrentState = SERVICE_STOPPED;
MsgrStatus.dwControlsAccepted = 0;
MsgrStatus.dwCheckPoint = 0;
MsgrStatus.dwWaitHint = 0;
MsgrState = STOPPED;
}
MsgrUninstallCode = ExitCode;
SET_SERVICE_EXITCODE(
ExitCode,
MsgrStatus.dwWin32ExitCode,
MsgrStatus.dwServiceSpecificExitCode
);
}
//
// Send the new status to the service controller.
//
if (MsgrStatusHandle == (SERVICE_STATUS_HANDLE) NULL) {
MSG_LOG(ERROR,
"MsgBeginForcedShutdown, no handle to call SetServiceStatus\n", 0);
}
else if (! SetServiceStatus( MsgrStatusHandle, &MsgrStatus )) {
status = GetLastError();
if (status != NERR_Success) {
MSG_LOG(ERROR,
"MsgBeginForcedShutdown,SetServiceStatus Failed %X\n",
status);
}
}
status = MsgrState;
RtlReleaseResource(&g_StateResource);
return status;
}
DWORD
MsgStatusUpdate(
IN DWORD NewState
)
/*++
Routine Description:
Sends a status to the Service Controller via SetServiceStatus.
The contents of the status message is controlled by this routine.
The caller simply passes in the desired state, and this routine does
the rest. For instance, if the Messenger passes in a STARTING state,
This routine will update the hint count that it maintains, and send
the appropriate information in the SetServiceStatus call.
This routine uses transitions in state to send determine which status
to send. For instance if the status was STARTING, and has changed
to RUNNING, this routine sends out an INSTALLED to the Service
Controller.
Arguments:
NewState - Can be any of the state flags:
UPDATE_ONLY - Simply send out the current status
STARTING - The Messenger is in the process of initializing
RUNNING - The Messenger has finished with initialization
STOPPING - The Messenger is in the process of shutting down
STOPPED - The Messenger has completed the shutdown.
Return Value:
CurrentState - This may not be the same as the NewState that was
passed in. It could be that the main thread is sending in a new
install state just after the Control Handler set the state to
STOPPING. In this case, the STOPPING state will be returned so as
to inform the main thread that a shut-down is in process.
Note:
--*/
{
DWORD status;
BOOL inhibit = FALSE; // Used to inhibit sending the status
// to the service controller.
RtlAcquireResourceExclusive(&g_StateResource, TRUE);
if (NewState == STOPPED) {
if (MsgrState == STOPPED) {
//
// It was already stopped, don't send another SetServiceStatus.
//
inhibit = TRUE;
}
else {
//
// The shut down is complete, indicate that the messenger
// has stopped.
//
MsgrStatus.dwCurrentState = SERVICE_STOPPED;
MsgrStatus.dwControlsAccepted = 0;
MsgrStatus.dwCheckPoint = 0;
MsgrStatus.dwWaitHint = 0;
SET_SERVICE_EXITCODE(
MsgrUninstallCode,
MsgrStatus.dwWin32ExitCode,
MsgrStatus.dwServiceSpecificExitCode
);
}
MsgrState = NewState;
}
else {
//
// We are not being asked to change to the STOPPED state.
//
switch(MsgrState) {
case STARTING:
if (NewState == STOPPING) {
MsgrStatus.dwCurrentState = SERVICE_STOP_PENDING;
MsgrStatus.dwControlsAccepted = 0;
MsgrStatus.dwCheckPoint = HintCount++;
MsgrStatus.dwWaitHint = 20000; // 20 seconds
MsgrState = NewState;
}
else if (NewState == RUNNING) {
//
// The Messenger Service has completed installation.
//
MsgrStatus.dwCurrentState = SERVICE_RUNNING;
MsgrStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
MsgrStatus.dwCheckPoint = 0;
MsgrStatus.dwWaitHint = 0;
MsgrState = NewState;
}
else {
//
// The NewState must be STARTING. So update the pending
// count
//
MsgrStatus.dwCurrentState = SERVICE_START_PENDING;
MsgrStatus.dwControlsAccepted = 0;
MsgrStatus.dwCheckPoint = HintCount++;
MsgrStatus.dwWaitHint = 20000; // 20 seconds
}
break;
case RUNNING:
if (NewState == STOPPING) {
MsgrStatus.dwCurrentState = SERVICE_STOP_PENDING;
MsgrStatus.dwControlsAccepted = 0;
MsgrStatus.dwCheckPoint = HintCount++;
MsgrStatus.dwWaitHint = 20000; // 20 seconds
MsgrState = NewState;
}
break;
case STOPPING:
//
// No matter what else was passed in, force the status to
// indicate that a shutdown is pending.
//
MsgrStatus.dwCurrentState = SERVICE_STOP_PENDING;
MsgrStatus.dwControlsAccepted = 0;
MsgrStatus.dwCheckPoint = HintCount++;
MsgrStatus.dwWaitHint = 20000; // 20 seconds
break;
case STOPPED:
//
// We're already stopped. Therefore, an uninstalled status
// as already been sent. Do nothing.
//
inhibit = TRUE;
break;
}
}
if (!inhibit) {
if (MsgrStatusHandle == (SERVICE_STATUS_HANDLE) NULL) {
MSG_LOG(ERROR,
"MsgStatusUpdate, no handle to call SetServiceStatus\n", 0);
}
else if (! SetServiceStatus( MsgrStatusHandle, &MsgrStatus )) {
status = GetLastError();
if (status != NERR_Success) {
MSG_LOG(ERROR,
"MsgStatusUpdate, SetServiceStatus Failed %d\n",
status);
}
}
}
status = MsgrState;
RtlReleaseResource(&g_StateResource);
return status;
}
DWORD
GetMsgrState (
VOID
)
/*++
Routine Description:
Obtains the state of the Messenger Service. This state information
is protected as a critical section such that only one thread can
modify or read it at a time.
Arguments:
none
Return Value:
The Messenger State is returned as the return value.
--*/
{
DWORD status;
RtlAcquireResourceShared(&g_StateResource, TRUE);
status = MsgrState;
RtlReleaseResource(&g_StateResource);
return status;
}
VOID
MsgrBlockStateChange(
VOID
)
{
RtlAcquireResourceShared(&g_StateResource, TRUE);
}
VOID
MsgrUnblockStateChange(
VOID
)
{
RtlReleaseResource(&g_StateResource);
}
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