[PATCH] ShellPkg/Shell: Check the OpenVolume result in OpenRootByHandle()

[Hao Wu <hao.a.wu@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=779

For the API EfiShellOpenRootByHandle():

The return status of the call to SimpleFileSystem->OpenVolume should be
checked.

It is possible that there is a media change in the device (like CD/DVD
ROM). In such case, the volume root opened and/or the device path opened
previously (also within EfiShellOpenRootByHandle) may be invalid.

This commit adds a check for the result of OpenVolume before subsequently
calling functions like EfiShellGetMapFromDevicePath() &
ConvertEfiFileProtocolToShellHandle().

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
---
 ShellPkg/Application/Shell/ShellProtocol.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/ShellPkg/Application/Shell/ShellProtocol.c b/ShellPkg/Application/Shell/ShellProtocol.c
index 5e34b8dad1..0dee267353 100644
--- a/ShellPkg/Application/Shell/ShellProtocol.c
+++ b/ShellPkg/Application/Shell/ShellProtocol.c
@@ -827,7 +827,8 @@ EfiShellGetDeviceName(
   @retval EFI_NOT_FOUND         EFI_SIMPLE_FILE_SYSTEM could not be found or the root directory
                                 could not be opened.
   @retval EFI_VOLUME_CORRUPTED  The data structures in the volume were corrupted.
-  @retval EFI_DEVICE_ERROR      The device had an error
+  @retval EFI_DEVICE_ERROR      The device had an error.
+  @retval EFI_MEDIA_CHANGED     The device has a different medium in it or the medium is no longer supported.
 **/
 EFI_STATUS
 EFIAPI
@@ -867,8 +868,12 @@ EfiShellOpenRootByHandle(
   // Open the root volume now...
   //
   Status = SimpleFileSystem->OpenVolume(SimpleFileSystem, &RealFileHandle);
+  if (EFI_ERROR(Status)) {
+    return Status;
+  }
+
   *FileHandle = ConvertEfiFileProtocolToShellHandle(RealFileHandle, EfiShellGetMapFromDevicePath(&DevPath));
-  return (Status);
+  return (EFI_SUCCESS);
 }
 
 /**
-- 
2.12.0.windows.1