[driver] Move key-name construction into reg_open()

Signed-off-by: Michael Brown <mbrown@fensystems.co.uk>
ipxe · Aug 15, 2011 · 5272575 · 5272575
1 parent de3a431
commit 5272575
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Showing 3 changed files with 45 additions and 29 deletions.
diff --git a/src/driver/ibft.c b/src/driver/ibft.c
@@ -209,32 +209,14 @@ static NTSTATUS store_tcpip_parameters ( PDEVICE_OBJECT pdo,
 					 PVOID opaque ) {
 	LPCWSTR key_name_prefix = ( L"\\Registry\\Machine\\SYSTEM\\"
 				    L"CurrentControlSet\\Services\\"
-				    L"Tcpip\\Parameters\\Interfaces\\" );
+				    L"Tcpip\\Parameters\\Interfaces" );
 	PIBFT_NIC nic = opaque;
-	LPWSTR key_name;
-	SIZE_T key_name_len;
 	HANDLE reg_key;
 	ULONG subnet_mask;
 	NTSTATUS status;
 
-	/* Allocate key name */
-	key_name_len = ( ( wcslen ( key_name_prefix ) +
-			   wcslen ( netcfginstanceid ) + 1 ) *
-			 sizeof ( key_name[0] ) );
-	key_name = ExAllocatePoolWithTag ( NonPagedPool, key_name_len,
-					   SANBOOTCONF_POOL_TAG );
-	if ( ! key_name ) {
-		DbgPrint ( "Could not allocate TCP/IP key name\n" );
-		status = STATUS_UNSUCCESSFUL;
-		goto err_exallocatepoolwithtag;
-	}
-
-	/* Construct key name */
-	RtlStringCbCopyW ( key_name, key_name_len, key_name_prefix );
-	RtlStringCbCatW ( key_name, key_name_len, netcfginstanceid );
-
 	/* Open key */
-	status = reg_open ( key_name, &reg_key );
+	status = reg_open ( &reg_key, key_name_prefix, netcfginstanceid, NULL );
 	if ( ! NT_SUCCESS ( status ) )
 		goto err_reg_open;
 
@@ -271,8 +253,6 @@ static NTSTATUS store_tcpip_parameters ( PDEVICE_OBJECT pdo,
  err_reg_store:
 	reg_close ( reg_key );
  err_reg_open:
-	ExFreePool ( key_name );
- err_exallocatepoolwithtag:
 	return status;
 }
 

diff --git a/src/driver/registry.c b/src/driver/registry.c
@@ -24,26 +24,62 @@
 /**
  * Open registry key
  *
- * @v reg_key_name	Registry key name
  * @v reg_key		Registry key to fill in
+ * @v ...		Registry key name components, terminated with a NULL
  * @ret ntstatus	NT status
  */
-NTSTATUS reg_open ( LPCWSTR reg_key_name, PHANDLE reg_key ) {
+NTSTATUS reg_open ( PHANDLE reg_key, ... ) {
 	UNICODE_STRING unicode_string;
 	OBJECT_ATTRIBUTES object_attrs;
+	va_list args;
+	LPCWSTR key_name_part;
+	LPWSTR key_name;
+	SIZE_T key_name_len;
 	NTSTATUS status;
 
-	RtlInitUnicodeString ( &unicode_string, reg_key_name );
+	/* Calculate total buffer length */
+	key_name_len = 0;
+	va_start ( args, reg_key );
+	while ( ( key_name_part = va_arg ( args, LPCWSTR ) ) != NULL ) {
+		key_name_len += ( ( wcslen ( key_name_part ) + 1 ) *
+				  sizeof ( key_name_part[0] ) );
+	}
+	va_end ( args );
+
+	/* Allocate buffer */
+	key_name = ExAllocatePoolWithTag ( NonPagedPool, key_name_len,
+					   SANBOOTCONF_POOL_TAG );
+	if ( ! key_name ) {
+		DbgPrint ( "Could not allocate key name buffer\n" );
+		status = STATUS_UNSUCCESSFUL;
+		goto err_exallocatepoolwithtag;
+	}
+
+	/* Create key name */
+	va_start ( args, reg_key );
+	key_name[0] = 0;
+	while ( ( key_name_part = va_arg ( args, LPCWSTR ) ) != NULL ) {
+		if ( key_name[0] )
+			RtlStringCbCatW ( key_name, key_name_len, L"\\" );
+		RtlStringCbCatW ( key_name, key_name_len, key_name_part );
+	}
+	va_end ( args );
+
+	/* Open key */
+	RtlInitUnicodeString ( &unicode_string, key_name );
 	InitializeObjectAttributes ( &object_attrs, &unicode_string,
 				     OBJ_KERNEL_HANDLE | OBJ_CASE_INSENSITIVE,
 				     NULL, NULL );
 	status = ZwOpenKey ( reg_key, KEY_ALL_ACCESS, &object_attrs );
 	if ( ! NT_SUCCESS ( status ) ) {
-		DbgPrint ( "Could not open %S: %x\n", reg_key_name, status );
-		return status;
+		DbgPrint ( "Could not open %S: %x\n", key_name, status );
+		goto err_zwopenkey;
 	}
 
-	return STATUS_SUCCESS;
+ err_zwopenkey:
+	ExFreePool ( key_name );
+ err_exallocatepoolwithtag:
+	return status;
 }
 
 /**

diff --git a/src/driver/registry.h b/src/driver/registry.h
@@ -19,7 +19,7 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-extern NTSTATUS reg_open ( LPCWSTR reg_key_name, PHANDLE reg_key );
+extern NTSTATUS reg_open ( PHANDLE reg_key, ... );
 extern VOID reg_close ( HANDLE reg_key );
 extern NTSTATUS reg_fetch_kvi ( HANDLE reg_key, LPCWSTR value_name,
 				PKEY_VALUE_PARTIAL_INFORMATION *kvi );