DriverEntry routine
DriverEntry is the first routine called after a driver is loaded, and is responsible for initializing the driver.
Syntax
DRIVER_INITIALIZE DriverEntry;
NTSTATUS DriverEntry(
__in struct _DRIVER_OBJECT *DriverObject,
__in PUNICODE_STRING RegistryPath
)
{ ... }
Parameters
- DriverObject [in]
-
A pointer to a DRIVER_OBJECT structure. This is the driver's driver object.
- RegistryPath [in]
-
A pointer to a counted Unicode string specifying the path to the driver's registry key.
Return value
If the routine succeeds, it must return STATUS_SUCCESS. Otherwise, it must return one of the error status values defined in Ntstatus.h.
Remarks
The DriverObject parameter supplies the DriverEntry routine with a pointer to the driver's driver object, which is allocated by the I/O manager. The DriverEntry routine must fill in the driver object with entry points for the driver's standard routines.
The DriverObject pointer gives the driver access to DriverObject->HardwareDatabase, which points to a counted Unicode string that specifies a path to the registry's \Registry\Machine\Hardware tree.
The registry path string pointed to by RegistryPath is of the form \Registry\Machine\System\CurrentControlSet\Services\DriverName. A driver can use this path to store driver-specific information; see Registry Keys for Drivers. The DriverEntry routine should save a copy of the Unicode string, not the pointer, since the I/O manager frees the RegistryPath buffer after DriverEntry returns.
For more information about implementing a DriverEntry routine, see Writing a DriverEntry Routine.
While it is possible to name this routine something other than DriverEntry, doing so is not recommended. The DDK-supplied build tools automatically inform the linker that the driver's entry point is called DriverEntry, so giving the routine another name requires you to modify the build tools. For more information about build tools, see Building a Driver.
Examples
To define a DriverEntry callback routine, you must first provide a function declaration that Static Driver Verifier (SDV) and other verification tools require, as shown in the following code example:
DRIVER_INITIALIZE DriverEntry;
Then, implement your callback routine as follows:
NTSTATUS
DriverEntry(
_In_ struct _DRIVER_OBJECT *DriverObject,
_In_ PUNICODE_STRING RegistryPath
)
{
// Function body
}
The DRIVER_INITIALIZE function type is defined in the Wdm.h header file. For more information about SDV requirements for function declarations, see Declaring Functions Using Function Role Types for WDM Drivers.
Requirements
|
Header |
|
|---|---|
|
IRQL | Called at PASSIVE_LEVEL. |
See also
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Build date: 4/2/2012
