On 7/19/2018 4:50 AM, Laszlo Ersek wrote:
+ //
+ // Traverse the device path nodes relative to the filesystem.
+ //
+ while (!IsDevicePathEnd (*FilePath)) {
+ //
+ // Keep local variables that relate to the current device path node tightly
+ // scoped.
+ //
+ FILEPATH_DEVICE_PATH *FilePathNode;
+ CHAR16 *AlignedPathName;
+ CHAR16 *PathName;
+ EFI_FILE_PROTOCOL *NextFile;
1. Not sure if it follows the coding style. I would prefer to move the
definition to the beginning of the function.
+
+ if (DevicePathType (*FilePath) != MEDIA_DEVICE_PATH ||
+ DevicePathSubType (*FilePath) != MEDIA_FILEPATH_DP) {
+ Status = EFI_INVALID_PARAMETER;
+ goto CloseLastFile;
+ }
+ FilePathNode = (FILEPATH_DEVICE_PATH *)*FilePath;
+
+ //
+ // FilePathNode->PathName may be unaligned, and the UEFI specification
+ // requires pointers that are passed to protocol member functions to be
+ // aligned. Create an aligned copy of the pathname if necessary.
+ //
+ if ((UINTN)FilePathNode->PathName % sizeof *FilePathNode->PathName == 0) {
+ AlignedPathName = NULL;
+ PathName = FilePathNode->PathName;
+ } else {
+ AlignedPathName = AllocateCopyPool (
+ (DevicePathNodeLength (FilePathNode) -
+ SIZE_OF_FILEPATH_DEVICE_PATH),
+ FilePathNode->PathName
+ );
+ if (AlignedPathName == NULL) {
+ Status = EFI_OUT_OF_RESOURCES;
+ goto CloseLastFile;
+ }
+ PathName = AlignedPathName;
+ }
+
+ //
+ // Open the next pathname fragment with EFI_FILE_MODE_CREATE masked out and
+ // with Attributes set to 0.
+ //
+ Status = LastFile->Open (
+ LastFile,
+ &NextFile,
+ PathName,
+ OpenMode & ~(UINT64)EFI_FILE_MODE_CREATE,
+ 0
+ );
2. As I said in previous mail, is it really needed?
Per spec it's not required. Per FAT driver implementation, it's also not
required.
+
+ //
+ // Retry with EFI_FILE_MODE_CREATE and the original Attributes if the first
+ // attempt failed, and the caller specified EFI_FILE_MODE_CREATE.
+ //
+ if (EFI_ERROR (Status) && (OpenMode & EFI_FILE_MODE_CREATE) != 0) {
+ Status = LastFile->Open (
+ LastFile,
+ &NextFile,
+ PathName,
+ OpenMode,
+ Attributes
+ );
+ }
+
+ //
+ // Release any AlignedPathName on both error and success paths; PathName is
+ // no longer needed.
+ //
+ if (AlignedPathName != NULL) {
+ FreePool (AlignedPathName);
+ }
+ if (EFI_ERROR (Status)) {
+ goto CloseLastFile;
+ }
+
+ //
+ // Advance to the next device path node.
+ //
+ LastFile->Close (LastFile);
+ LastFile = NextFile;
+ *FilePath = NextDevicePathNode (FilePathNode);
+ }
+
+ *File = LastFile;
+ return EFI_SUCCESS;
+
+CloseLastFile:
+ LastFile->Close (LastFile);
+
+ ASSERT (EFI_ERROR (Status));
3. ASSERT_EFI_ERROR (Status);
+ return Status;
+}
--
Thanks,
Ray
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