[PATCH v2 5/7] SecurityPkg/SecureBootConfigDxe: replace OpenFileByDevicePath() with UefiLib API

[Laszlo Ersek <lersek@redhat.com>]

Replace the OpenFileByDevicePath() function with EfiOpenFileByDevicePath()
from UefiLib, correcting the following issues:

- imprecise comments on OpenFileByDevicePath(),
- code duplication between this module and other modules,
- local variable name "EfiSimpleFileSystemProtocol" starting with "Efi"
  prefix,
- bogus "FileHandle = NULL" assignments,
- leaking "Handle1" when the device path type/subtype check or the
  realignment-motivated AllocateCopyPool() fails in the loop,
- stale SHELL_FILE_HANDLE reference in a comment.

Cc: Chao Zhang <chao.b.zhang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Roman Bacik <roman.bacik@broadcom.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1008
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
---

Notes:
    v2:
    
    - pick up Chao's and Jaben's R-b's
    
    - insert a space character between "EfiOpenFileByDevicePath" and "(" --
      it was missing from the pre-patch code too

 SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf        |   1 -
 SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigFileExplorer.c | 151 +-------------------
 2 files changed, 1 insertion(+), 151 deletions(-)

diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf
index 487fc8cda917..caf95ddac7d9 100644
--- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf
+++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf
@@ -114,7 +114,6 @@ [Guids]
 [Protocols]
   gEfiHiiConfigAccessProtocolGuid               ## PRODUCES
   gEfiDevicePathProtocolGuid                    ## PRODUCES
-  gEfiSimpleFileSystemProtocolGuid              ## SOMETIMES_CONSUMES
   gEfiBlockIoProtocolGuid                       ## SOMETIMES_CONSUMES
 
 [Depex]
diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigFileExplorer.c b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigFileExplorer.c
index 2a26c20f394c..aef85c470143 100644
--- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigFileExplorer.c
+++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigFileExplorer.c
@@ -80,155 +80,6 @@ CleanUpPage (
     );
 }
 
-/**
-  This function will open a file or directory referenced by DevicePath.
-
-  This function opens a file with the open mode according to the file path. The
-  Attributes is valid only for EFI_FILE_MODE_CREATE.
-
-  @param[in, out]  FilePath        On input, the device path to the file.
-                                   On output, the remaining device path.
-  @param[out]      FileHandle      Pointer to the file handle.
-  @param[in]       OpenMode        The mode to open the file with.
-  @param[in]       Attributes      The file's file attributes.
-
-  @retval EFI_SUCCESS              The information was set.
-  @retval EFI_INVALID_PARAMETER    One of the parameters has an invalid value.
-  @retval EFI_UNSUPPORTED          Could not open the file path.
-  @retval EFI_NOT_FOUND            The specified file could not be found on the
-                                   device or the file system could not be found on
-                                   the device.
-  @retval EFI_NO_MEDIA             The device has no medium.
-  @retval EFI_MEDIA_CHANGED        The device has a different medium in it or the
-                                   medium is no longer supported.
-  @retval EFI_DEVICE_ERROR         The device reported an error.
-  @retval EFI_VOLUME_CORRUPTED     The file system structures are corrupted.
-  @retval EFI_WRITE_PROTECTED      The file or medium is write protected.
-  @retval EFI_ACCESS_DENIED        The file was opened read only.
-  @retval EFI_OUT_OF_RESOURCES     Not enough resources were available to open the
-                                   file.
-  @retval EFI_VOLUME_FULL          The volume is full.
-**/
-EFI_STATUS
-EFIAPI
-OpenFileByDevicePath(
-  IN OUT EFI_DEVICE_PATH_PROTOCOL     **FilePath,
-  OUT EFI_FILE_HANDLE                 *FileHandle,
-  IN UINT64                           OpenMode,
-  IN UINT64                           Attributes
-  )
-{
-  EFI_STATUS                      Status;
-  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *EfiSimpleFileSystemProtocol;
-  EFI_FILE_PROTOCOL               *Handle1;
-  EFI_FILE_PROTOCOL               *Handle2;
-  EFI_HANDLE                      DeviceHandle;
-  CHAR16                          *PathName;
-  UINTN                           PathLength;
-
-  if ((FilePath == NULL || FileHandle == NULL)) {
-    return EFI_INVALID_PARAMETER;
-  }
-
-  Status = gBS->LocateDevicePath (
-                  &gEfiSimpleFileSystemProtocolGuid,
-                  FilePath,
-                  &DeviceHandle
-                  );
-  if (EFI_ERROR (Status)) {
-    return Status;
-  }
-
-  Status = gBS->OpenProtocol(
-                  DeviceHandle,
-                  &gEfiSimpleFileSystemProtocolGuid,
-                  (VOID**)&EfiSimpleFileSystemProtocol,
-                  gImageHandle,
-                  NULL,
-                  EFI_OPEN_PROTOCOL_GET_PROTOCOL
-                  );
-  if (EFI_ERROR (Status)) {
-    return Status;
-  }
-
-  Status = EfiSimpleFileSystemProtocol->OpenVolume(EfiSimpleFileSystemProtocol, &Handle1);
-  if (EFI_ERROR (Status)) {
-    FileHandle = NULL;
-    return Status;
-  }
-
-  //
-  // go down directories one node at a time.
-  //
-  while (!IsDevicePathEnd (*FilePath)) {
-    //
-    // For file system access each node should be a file path component
-    //
-    if (DevicePathType    (*FilePath) != MEDIA_DEVICE_PATH ||
-        DevicePathSubType (*FilePath) != MEDIA_FILEPATH_DP
-       ) {
-      FileHandle = NULL;
-      return (EFI_INVALID_PARAMETER);
-    }
-    //
-    // Open this file path node
-    //
-    Handle2  = Handle1;
-    Handle1 = NULL;
-    PathLength = DevicePathNodeLength (*FilePath) - sizeof (EFI_DEVICE_PATH_PROTOCOL);
-    PathName = AllocateCopyPool (PathLength, ((FILEPATH_DEVICE_PATH*)*FilePath)->PathName);
-    if (PathName == NULL) {
-      return EFI_OUT_OF_RESOURCES;
-    }
-
-    //
-    // Try to test opening an existing file
-    //
-    Status = Handle2->Open (
-                          Handle2,
-                          &Handle1,
-                          PathName,
-                          OpenMode &~EFI_FILE_MODE_CREATE,
-                          0
-                         );
-
-    //
-    // see if the error was that it needs to be created
-    //
-    if ((EFI_ERROR (Status)) && (OpenMode != (OpenMode &~EFI_FILE_MODE_CREATE))) {
-      Status = Handle2->Open (
-                            Handle2,
-                            &Handle1,
-                            PathName,
-                            OpenMode,
-                            Attributes
-                           );
-    }
-    //
-    // Close the last node
-    //
-    Handle2->Close (Handle2);
-
-    FreePool (PathName);
-
-    if (EFI_ERROR(Status)) {
-      return (Status);
-    }
-
-    //
-    // Get the next node
-    //
-    *FilePath = NextDevicePathNode (*FilePath);
-  }
-
-  //
-  // This is a weak spot since if the undefined SHELL_FILE_HANDLE format changes this must change also!
-  //
-  *FileHandle = (VOID*)Handle1;
-  return EFI_SUCCESS;
-}
-
-
 /**
   Extract filename from device path. The returned buffer is allocated using AllocateCopyPool.
   The caller is responsible for freeing the allocated buffer using FreePool(). If return NULL
@@ -312,7 +163,7 @@ UpdatePage(
 
   gSecureBootPrivateData->FileContext->FileName = FileName;
 
-  OpenFileByDevicePath(
+  EfiOpenFileByDevicePath (
     &FilePath,
     &gSecureBootPrivateData->FileContext->FHandle,
     EFI_FILE_MODE_READ,
-- 
2.14.1.3.gb7cf6e02401b