cmlazy.c File Reference

#include "ntoskrnl.h"
#include "debug.h"

Include dependency graph for cmlazy.c:

Go to the source code of this file.

Macros
#define	NDEBUG

Functions
BOOLEAN NTAPI	CmpDoFlushNextHive (_In_ BOOLEAN ForceFlush, _Out_ PBOOLEAN Error, _Out_ PULONG DirtyCount)
	_Function_class_ (KDEFERRED_ROUTINE)
VOID NTAPI	CmpLazyFlush (VOID)
	_Function_class_ (WORKER_THREAD_ROUTINE)
VOID NTAPI	CmpCmdInit (IN BOOLEAN SetupBoot)
NTSTATUS NTAPI	CmpCmdHiveOpen (IN POBJECT_ATTRIBUTES FileAttributes, IN PSECURITY_CLIENT_CONTEXT ImpersonationContext, IN OUT PBOOLEAN Allocate, OUT PCMHIVE *NewHive, IN ULONG CheckFlags)
VOID NTAPI	CmpShutdownWorkers (VOID)
VOID NTAPI	CmSetLazyFlushState (IN BOOLEAN Enable)

Variables
KTIMER	CmpLazyFlushTimer
KDPC	CmpLazyFlushDpc
WORK_QUEUE_ITEM	CmpLazyWorkItem
KTIMER	CmpEnableLazyFlushTimer
KDPC	CmpEnableLazyFlushDpc
BOOLEAN	CmpLazyFlushPending
BOOLEAN	CmpForceForceFlush
BOOLEAN	CmpHoldLazyFlush = TRUE
ULONG	CmpLazyFlushIntervalInSeconds = 5
ULONG	CmpLazyFlushHiveCount = 7
ULONG	CmpLazyFlushCount = 1
LONG	CmpFlushStarveWriters

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 11 of file cmlazy.c.

Function Documentation

_Function_class_() [1/2]

_Function_class_

(

KDEFERRED_ROUTINE

)

Definition at line 126 of file cmlazy.c.

{
    /* Don't stop lazy flushing from happening anymore */
    CmpHoldLazyFlush = FALSE;
}

_Function_class_() [2/2]

_Function_class_

(

WORKER_THREAD_ROUTINE

)

Definition at line 172 of file cmlazy.c.

{
    BOOLEAN ForceFlush, Result, MoreWork = FALSE;
    ULONG DirtyCount = 0;
    PAGED_CODE();
 
    /* Don't do anything if lazy flushing isn't enabled yet */
    if (CmpHoldLazyFlush)
    {
        DPRINT1("Lazy flush held. Bye bye.\n");
        CmpLazyFlushPending = FALSE;
        return;
    }
 
    /* Check if we are forcing a flush */
    ForceFlush = CmpForceForceFlush;
    if (ForceFlush)
    {
        DPRINT("Forcing flush.\n");
        /* Lock the registry exclusively */
        CmpLockRegistryExclusive();
    }
    else
    {
        DPRINT("Not forcing flush.\n");
        /* Starve writers before locking */
        InterlockedIncrement(&CmpFlushStarveWriters);
        CmpLockRegistry();
    }
 
    /* Flush the next hive */
    MoreWork = CmpDoFlushNextHive(ForceFlush, &Result, &DirtyCount);
    if (!MoreWork)
    {
        /* We're done */
        InterlockedIncrement((PLONG)&CmpLazyFlushCount);
    }
 
    /* Check if we have starved writers */
    if (!ForceFlush)
        InterlockedDecrement(&CmpFlushStarveWriters);
 
    /* Not pending anymore, release the registry lock */
    CmpLazyFlushPending = FALSE;
    CmpUnlockRegistry();
 
    DPRINT("Lazy flush done. More work to be done: %s. Entries still dirty: %u.\n",
        MoreWork ? "Yes" : "No", DirtyCount);
 
    if (MoreWork)
    {
        /* Relaunch the flush timer, so the remaining hives get flushed */
        CmpLazyFlush();
    }
}

CmpCmdHiveOpen()

NTSTATUS NTAPI CmpCmdHiveOpen	(	IN POBJECT_ATTRIBUTES	FileAttributes,
		IN PSECURITY_CLIENT_CONTEXT	ImpersonationContext,
		IN OUT PBOOLEAN	Allocate,
		OUT PCMHIVE *	NewHive,
		IN ULONG	CheckFlags
	)

Definition at line 276 of file cmlazy.c.

{
    NTSTATUS Status;
    UNICODE_STRING FileName;
    PWCHAR FilePath;
    ULONG Length;
    OBJECT_NAME_INFORMATION DummyNameInfo;
    POBJECT_NAME_INFORMATION FileNameInfo;
 
    PAGED_CODE();
 
    if (FileAttributes->RootDirectory)
    {
        /*
         * Validity check: The ObjectName is relative to RootDirectory,
         * therefore it must not start with a path separator.
         */
        if (FileAttributes->ObjectName && FileAttributes->ObjectName->Buffer &&
            FileAttributes->ObjectName->Length >= sizeof(WCHAR) &&
            *FileAttributes->ObjectName->Buffer == OBJ_NAME_PATH_SEPARATOR)
        {
            return STATUS_OBJECT_PATH_SYNTAX_BAD;
        }
 
        /* Determine the right buffer size and allocate */
        Status = ZwQueryObject(FileAttributes->RootDirectory,
                               ObjectNameInformation,
                               &DummyNameInfo,
                               sizeof(DummyNameInfo),
                               &Length);
        if (Status != STATUS_BUFFER_OVERFLOW)
        {
            DPRINT1("CmpCmdHiveOpen(): Root directory handle object name size query failed, Status = 0x%08lx\n", Status);
            return Status;
        }
 
        FileNameInfo = ExAllocatePoolWithTag(PagedPool,
                                             Length + sizeof(UNICODE_NULL),
                                             TAG_CM);
        if (FileNameInfo == NULL)
        {
            DPRINT1("CmpCmdHiveOpen(): Unable to allocate memory\n");
            return STATUS_INSUFFICIENT_RESOURCES;
        }
 
        /* Try to get the value */
        Status = ZwQueryObject(FileAttributes->RootDirectory,
                               ObjectNameInformation,
                               FileNameInfo,
                               Length,
                               &Length);
        if (!NT_SUCCESS(Status))
        {
            /* Fail */
            DPRINT1("CmpCmdHiveOpen(): Root directory handle object name query failed, Status = 0x%08lx\n", Status);
            ExFreePoolWithTag(FileNameInfo, TAG_CM);
            return Status;
        }
 
        /* Null-terminate and add the length of the terminator */
        Length -= sizeof(OBJECT_NAME_INFORMATION);
        FilePath = FileNameInfo->Name.Buffer;
        FilePath[Length / sizeof(WCHAR)] = UNICODE_NULL;
        Length += sizeof(UNICODE_NULL);
 
        /* Compute the size of the full path; Length already counts the terminating NULL */
        Length = Length + sizeof(WCHAR) + FileAttributes->ObjectName->Length;
        if (Length > MAXUSHORT)
        {
            /* Name size too long, bail out */
            ExFreePoolWithTag(FileNameInfo, TAG_CM);
            return STATUS_OBJECT_PATH_INVALID;
        }
 
        /* Build the full path */
        RtlInitEmptyUnicodeString(&FileName, NULL, 0);
        FileName.Buffer = ExAllocatePoolWithTag(PagedPool, Length, TAG_CM);
        if (!FileName.Buffer)
        {
            /* Fail */
            DPRINT1("CmpCmdHiveOpen(): Unable to allocate memory\n");
            ExFreePoolWithTag(FileNameInfo, TAG_CM);
            return STATUS_INSUFFICIENT_RESOURCES;
        }
        FileName.MaximumLength = Length;
        RtlCopyUnicodeString(&FileName, &FileNameInfo->Name);
        ExFreePoolWithTag(FileNameInfo, TAG_CM);
 
        /*
         * Append a path terminator if needed (we have already accounted
         * for a possible extra one when allocating the buffer).
         */
        if (/* FileAttributes->ObjectName->Buffer[0] != OBJ_NAME_PATH_SEPARATOR && */ // We excluded ObjectName starting with a path separator above.
            FileName.Length > 0 && FileName.Buffer[FileName.Length / sizeof(WCHAR) - 1] != OBJ_NAME_PATH_SEPARATOR)
        {
            /* ObjectName does not start with '\' and PathBuffer does not end with '\' */
            FileName.Buffer[FileName.Length / sizeof(WCHAR)] = OBJ_NAME_PATH_SEPARATOR;
            FileName.Length += sizeof(WCHAR);
            FileName.Buffer[FileName.Length / sizeof(WCHAR)] = UNICODE_NULL;
        }
 
        /* Append the object name */
        Status = RtlAppendUnicodeStringToString(&FileName, FileAttributes->ObjectName);
        if (!NT_SUCCESS(Status))
        {
            /* Fail */
            DPRINT1("CmpCmdHiveOpen(): RtlAppendUnicodeStringToString() failed, Status = 0x%08lx\n", Status);
            ExFreePoolWithTag(FileName.Buffer, TAG_CM);
            return Status;
        }
    }
    else
    {
        FileName = *FileAttributes->ObjectName;
    }
 
    /* Open the file in the current security context */
    Status = CmpInitHiveFromFile(&FileName,
                                 0,
                                 NewHive,
                                 Allocate,
                                 CheckFlags);
    if (((Status == STATUS_ACCESS_DENIED) ||
         (Status == STATUS_NO_SUCH_USER) ||
         (Status == STATUS_WRONG_PASSWORD) ||
         (Status == STATUS_ACCOUNT_EXPIRED) ||
         (Status == STATUS_ACCOUNT_DISABLED) ||
         (Status == STATUS_ACCOUNT_RESTRICTION)) &&
        ImpersonationContext)
    {
        /* We failed due to an account/security error, impersonate SYSTEM */
        Status = SeImpersonateClientEx(ImpersonationContext, NULL);
        if (NT_SUCCESS(Status))
        {
            /* Now try again */
            Status = CmpInitHiveFromFile(&FileName,
                                         0,
                                         NewHive,
                                         Allocate,
                                         CheckFlags);
 
            /* Restore impersonation token */
            PsRevertToSelf();
        }
    }
 
    if (FileAttributes->RootDirectory)
    {
        ExFreePoolWithTag(FileName.Buffer, TAG_CM);
    }
 
    /* Return status of open attempt */
    return Status;
}

Referenced by CmLoadKey().

CmpCmdInit()

VOID NTAPI CmpCmdInit

(

IN BOOLEAN

SetupBoot

)

Definition at line 233 of file cmlazy.c.

{
    LARGE_INTEGER DueTime;
    PAGED_CODE();
 
    /* Setup the lazy DPC */
    KeInitializeDpc(&CmpLazyFlushDpc, CmpLazyFlushDpcRoutine, NULL);
 
    /* Setup the lazy timer */
    KeInitializeTimer(&CmpLazyFlushTimer);
 
    /* Setup the lazy worker */
    ExInitializeWorkItem(&CmpLazyWorkItem, CmpLazyFlushWorker, NULL);
 
    /* Setup the forced-lazy DPC and timer */
    KeInitializeDpc(&CmpEnableLazyFlushDpc,
                    CmpEnableLazyFlushDpcRoutine,
                    NULL);
    KeInitializeTimer(&CmpEnableLazyFlushTimer);
 
    /* Enable lazy flushing after 10 minutes */
    DueTime.QuadPart = Int32x32To64(600, -10 * 1000 * 1000);
    KeSetTimer(&CmpEnableLazyFlushTimer, DueTime, &CmpEnableLazyFlushDpc);
 
    /* Setup flush variables */
    CmpNoWrite = CmpMiniNTBoot;
    CmpWasSetupBoot = SetupBoot;
 
    /* Testing: Force Lazy Flushing */
    CmpHoldLazyFlush = FALSE;
 
    /* Setup the system hives list if this is not a Setup boot */
    if (!SetupBoot)
        CmpInitializeHiveList();
 
    /* Now that the system hives are loaded, if we are in PE mode,
     * all other hives will be loaded with full access */
    if (CmpMiniNTBoot)
        CmpShareSystemHives = FALSE;
}

Referenced by NtInitializeRegistry().

CmpDoFlushNextHive()

BOOLEAN NTAPI CmpDoFlushNextHive	(	_In_ BOOLEAN	ForceFlush,
		_Out_ PBOOLEAN	Error,
		_Out_ PULONG	DirtyCount
	)

Definition at line 33 of file cmlazy.c.

{
    NTSTATUS Status;
    PLIST_ENTRY NextEntry;
    PCMHIVE CmHive;
    BOOLEAN Result;
    ULONG HiveCount = CmpLazyFlushHiveCount;
 
    /* Set Defaults */
    *Error = FALSE;
    *DirtyCount = 0;
 
    /* Don't do anything if we're not supposed to */
    if (CmpNoWrite) return TRUE;
 
    /* Make sure we have to flush at least one hive */
    if (!HiveCount) HiveCount = 1;
 
    /* Acquire the list lock and loop */
    ExAcquirePushLockShared(&CmpHiveListHeadLock);
    NextEntry = CmpHiveListHead.Flink;
    while ((NextEntry != &CmpHiveListHead) && HiveCount)
    {
        /* Get the hive and check if we should flush it */
        CmHive = CONTAINING_RECORD(NextEntry, CMHIVE, HiveList);
        if (!(CmHive->Hive.HiveFlags & HIVE_NOLAZYFLUSH) &&
            (CmHive->FlushCount != CmpLazyFlushCount))
        {
            /* Great success! */
            Result = TRUE;
 
            /* One less to flush */
            HiveCount--;
 
            /* Ignore clean or volatile hives */
            if ((!CmHive->Hive.DirtyCount && !ForceFlush) ||
                (CmHive->Hive.HiveFlags & HIVE_VOLATILE))
            {
                /* Don't do anything but do update the count */
                CmHive->FlushCount = CmpLazyFlushCount;
                DPRINT("Hive %wZ is clean.\n", &CmHive->FileFullPath);
            }
            else
            {
                /* Do the sync */
                DPRINT("Flushing: %wZ\n", &CmHive->FileFullPath);
                DPRINT("Handle: %p\n", CmHive->FileHandles[HFILE_TYPE_PRIMARY]);
                Status = HvSyncHive(&CmHive->Hive);
                if (!NT_SUCCESS(Status))
                {
                    /* Let them know we failed */
                    DPRINT1("Failed to flush %wZ on handle %p (status 0x%08lx)\n",
                        &CmHive->FileFullPath,  CmHive->FileHandles[HFILE_TYPE_PRIMARY], Status);
                    *Error = TRUE;
                    Result = FALSE;
                    break;
                }
                CmHive->FlushCount = CmpLazyFlushCount;
            }
        }
        else if (CmHive->Hive.DirtyCount &&
                 !(CmHive->Hive.HiveFlags & HIVE_VOLATILE) &&
                 !(CmHive->Hive.HiveFlags & HIVE_NOLAZYFLUSH))
        {
            /* Use another lazy flusher for this hive */
            ASSERT(CmHive->FlushCount == CmpLazyFlushCount);
            *DirtyCount += CmHive->Hive.DirtyCount;
            DPRINT("CmHive %wZ already uptodate.\n", &CmHive->FileFullPath);
        }
 
        /* Try the next one */
        NextEntry = NextEntry->Flink;
    }
 
    /* Check if we've flushed everything */
    if (NextEntry == &CmpHiveListHead)
    {
        /* We have, tell the caller we're done */
        Result = FALSE;
    }
    else
    {
        /* We need to be called again */
        Result = TRUE;
    }
 
    /* Unlock the list and return the result */
    ExReleasePushLock(&CmpHiveListHeadLock);
    return Result;
}

Referenced by _Function_class_().

CmpLazyFlush()

VOID NTAPI CmpLazyFlush

(

VOID

)

Definition at line 157 of file cmlazy.c.

{
    LARGE_INTEGER DueTime;
    PAGED_CODE();
 
    /* Check if we should set the lazy flush timer */
    if (!CmpNoWrite && !CmpHoldLazyFlush)
    {
        /* Do it */
        DueTime.QuadPart = Int32x32To64(CmpLazyFlushIntervalInSeconds,
                                        -10 * 1000 * 1000);
        KeSetTimer(&CmpLazyFlushTimer, DueTime, &CmpLazyFlushDpc);
    }
}

Referenced by _Function_class_(), HvMarkCellDirty(), and NtInitializeRegistry().

CmpShutdownWorkers()

VOID NTAPI CmpShutdownWorkers

(

VOID

)

Definition at line 437 of file cmlazy.c.

{
    /* Stop lazy flushing */
    PAGED_CODE();
    KeCancelTimer(&CmpLazyFlushTimer);
}

Referenced by CmShutdownSystem().

CmSetLazyFlushState()

VOID NTAPI CmSetLazyFlushState

(

IN BOOLEAN

Enable

)

Definition at line 446 of file cmlazy.c.

{
    /* Set state for lazy flusher */
    CmpHoldLazyFlush = !Enable;
}

Referenced by NtSetSystemPowerState().

Variable Documentation

CmpEnableLazyFlushDpc

KDPC CmpEnableLazyFlushDpc

Definition at line 20 of file cmlazy.c.

Referenced by CmpCmdInit().

CmpEnableLazyFlushTimer

KTIMER CmpEnableLazyFlushTimer

Definition at line 19 of file cmlazy.c.

Referenced by CmpCmdInit().

CmpFlushStarveWriters

LONG CmpFlushStarveWriters

Definition at line 27 of file cmlazy.c.

Referenced by _Function_class_(), CmpLockRegistry(), and CmpLockRegistryExclusive().

CmpForceForceFlush

BOOLEAN CmpForceForceFlush

Definition at line 22 of file cmlazy.c.

Referenced by _Function_class_(), and CmpDoFlushAll().

CmpHoldLazyFlush

BOOLEAN CmpHoldLazyFlush = TRUE

Definition at line 23 of file cmlazy.c.

Referenced by _Function_class_(), CmpCmdInit(), CmpDereferenceKeyControlBlockWithLock(), CmpLazyFlush(), CmSetLazyFlushState(), and NtInitializeRegistry().

CmpLazyFlushCount

ULONG CmpLazyFlushCount = 1

Definition at line 26 of file cmlazy.c.

Referenced by _Function_class_(), and CmpDoFlushNextHive().

CmpLazyFlushDpc

KDPC CmpLazyFlushDpc

Definition at line 17 of file cmlazy.c.

Referenced by CmpCmdInit(), and CmpLazyFlush().

CmpLazyFlushHiveCount

ULONG CmpLazyFlushHiveCount = 7

Definition at line 25 of file cmlazy.c.

Referenced by CmpDoFlushNextHive().

CmpLazyFlushIntervalInSeconds

ULONG CmpLazyFlushIntervalInSeconds = 5

Definition at line 24 of file cmlazy.c.

Referenced by CmpLazyFlush().

CmpLazyFlushPending

BOOLEAN CmpLazyFlushPending

Definition at line 21 of file cmlazy.c.

Referenced by _Function_class_().

CmpLazyFlushTimer

KTIMER CmpLazyFlushTimer

Definition at line 16 of file cmlazy.c.

Referenced by CmpCmdInit(), CmpLazyFlush(), and CmpShutdownWorkers().

CmpLazyWorkItem

WORK_QUEUE_ITEM CmpLazyWorkItem

Definition at line 18 of file cmlazy.c.

Referenced by CmpCmdInit().