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[NTOSKRNL]

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- Cache the next instance value in the the registry so we don't have to go searching for an unused instance number every time we add a new device

svn path=/trunk/; revision=46808
This commit is contained in:
Cameron Gutman 2010-04-10 04:11:45 +00:00
parent aca1c8384f
commit f3683186aa
1 changed files with 75 additions and 15 deletions
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90
reactos/ntoskrnl/io/pnpmgr/pnproot.c
View file

@ -139,29 +139,19 @@ PnpRootCreateDevice(
WCHAR InstancePath[5];
PPNPROOT_DEVICE Device = NULL;
NTSTATUS Status;
ULONG i;
UNICODE_STRING PathSep = RTL_CONSTANT_STRING(L"\\");
ULONG NextInstance;
UNICODE_STRING EnumKeyName = RTL_CONSTANT_STRING(L"\\Registry\\Machine\\" REGSTR_PATH_SYSTEMENUM);
HANDLE EnumHandle, DeviceKeyHandle = INVALID_HANDLE_VALUE;
RTL_QUERY_REGISTRY_TABLE QueryTable[2];
OBJECT_ATTRIBUTES ObjectAttributes;
DeviceExtension = PnpRootDeviceObject->DeviceExtension;
KeAcquireGuardedMutex(&DeviceExtension->DeviceListLock);
DPRINT("Creating a PnP root device for service '%wZ'\n", ServiceName);
/* Search for a free instance ID */
_snwprintf(DevicePath, sizeof(DevicePath) / sizeof(WCHAR), L"%s\\%wZ", REGSTR_KEY_ROOTENUM, ServiceName);
for (i = 0; i < 9999; i++)
{
_snwprintf(InstancePath, sizeof(InstancePath) / sizeof(WCHAR), L"%04lu", i);
Status = LocateChildDevice(DeviceExtension, DevicePath, InstancePath, &Device);
if (Status == STATUS_NO_SUCH_DEVICE)
break;
}
if (i == 9999)
{
DPRINT1("Too much legacy devices reported for service '%wZ'\n", ServiceName);
Status = STATUS_INSUFFICIENT_RESOURCES;
goto cleanup;
}
/* Initialize a PNPROOT_DEVICE structure */
Device = ExAllocatePoolWithTag(PagedPool, sizeof(PNPROOT_DEVICE), TAG_PNP_ROOT);
@ -177,6 +167,74 @@ PnpRootCreateDevice(
Status = STATUS_NO_MEMORY;
goto cleanup;
}
Status = IopOpenRegistryKeyEx(&EnumHandle, NULL, &EnumKeyName, KEY_READ);
if (NT_SUCCESS(Status))
{
InitializeObjectAttributes(&ObjectAttributes, &Device->DeviceID, OBJ_CASE_INSENSITIVE, EnumHandle, NULL);
Status = ZwCreateKey(&DeviceKeyHandle, KEY_SET_VALUE, &ObjectAttributes, 0, NULL, 0, NULL);
ZwClose(EnumHandle);
}
if (!NT_SUCCESS(Status))
{
DPRINT1("Failed to open registry key\n");
goto cleanup;
}
tryagain:
RtlZeroMemory(QueryTable, sizeof(QueryTable));
QueryTable[0].Name = L"NextInstance";
QueryTable[0].EntryContext = &NextInstance;
QueryTable[0].Flags = RTL_QUERY_REGISTRY_DIRECT | RTL_QUERY_REGISTRY_REQUIRED;
Status = RtlQueryRegistryValues(RTL_REGISTRY_HANDLE,
(PWSTR)DeviceKeyHandle,
QueryTable,
NULL,
NULL);
if (!NT_SUCCESS(Status))
{
for (NextInstance = 0; NextInstance <= 9999; NextInstance++)
{
_snwprintf(InstancePath, sizeof(InstancePath) / sizeof(WCHAR), L"%04lu", NextInstance);
Status = LocateChildDevice(DeviceExtension, DevicePath, InstancePath, &Device);
if (Status == STATUS_NO_SUCH_DEVICE)
break;
}
if (NextInstance > 9999)
{
DPRINT1("Too many legacy devices reported for service '%wZ'\n", ServiceName);
Status = STATUS_INSUFFICIENT_RESOURCES;
goto cleanup;
}
}
_snwprintf(InstancePath, sizeof(InstancePath) / sizeof(WCHAR), L"%04lu", NextInstance);
Status = LocateChildDevice(DeviceExtension, DevicePath, InstancePath, &Device);
if (Status != STATUS_NO_SUCH_DEVICE || NextInstance > 9999)
{
DPRINT1("NextInstance value is corrupt! (%d)\n", NextInstance);
RtlDeleteRegistryValue(RTL_REGISTRY_HANDLE,
(PWSTR)DeviceKeyHandle,
L"NextInstance");
goto tryagain;
}
NextInstance++;
Status = RtlWriteRegistryValue(RTL_REGISTRY_HANDLE,
(PWSTR)DeviceKeyHandle,
L"NextInstance",
REG_DWORD,
&NextInstance,
sizeof(NextInstance));
if (!NT_SUCCESS(Status))
{
DPRINT1("Failed to write new NextInstance value! (0x%x)\n", Status);
goto cleanup;
}
if (!RtlCreateUnicodeString(&Device->InstanceID, InstancePath))
{
Status = STATUS_NO_MEMORY;
@ -243,6 +301,8 @@ cleanup:
RtlFreeUnicodeString(&Device->InstanceID);
ExFreePoolWithTag(Device, TAG_PNP_ROOT);
}
if (DeviceKeyHandle != INVALID_HANDLE_VALUE)
ZwClose(DeviceKeyHandle);
return Status;
}