The EDK 1 Shell (available at <https://github.com/tianocore/edk-Shell>)
has a bug in its EFI_SHELL_ENVIRONMENT2.Execute() implementation that
edk2's UefiShellLib has no choice but to work around.
Improve the explanation in the code. Also, document the implicit
EFI_HANDLE -> (EFI_HANDLE*) conversion, which happens implicitly after
dereferencing ParentHandle, with an explicit cast.
In practice, this patch is a no-op.
Cc: Jaben Carsey <jaben.car...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Zhichao Gao <zhichao....@intel.com>
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
---
Notes:
build-tested only
ShellPkg/Library/UefiShellLib/UefiShellLib.c | 22 ++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/ShellPkg/Library/UefiShellLib/UefiShellLib.c
b/ShellPkg/Library/UefiShellLib/UefiShellLib.c
index 835d0f88ca74..9f07a58eb23d 100644
--- a/ShellPkg/Library/UefiShellLib/UefiShellLib.c
+++ b/ShellPkg/Library/UefiShellLib/UefiShellLib.c
@@ -1291,9 +1291,27 @@ ShellExecute (
if (mEfiShellEnvironment2 != NULL) {
//
// Call EFI Shell version.
- // Due to oddity in the EFI shell we want to dereference the ParentHandle
here
//
- CmdStatus = (mEfiShellEnvironment2->Execute(*ParentHandle,
+ // Due to an unfixable bug in the EdkShell implementation, we must
+ // dereference "ParentHandle" here:
+ //
+ // 1. The EFI shell installs the EFI_SHELL_ENVIRONMENT2 protocol,
+ // identified by gEfiShellEnvironment2Guid.
+ // 2. The Execute() member function takes "ParentImageHandle" as first
+ // parameter, with type (EFI_HANDLE*).
+ // 3. In the EdkShell implementation, SEnvExecute() implements the
+ // Execute() member function. It passes "ParentImageHandle" correctly to
+ // SEnvDoExecute().
+ // 4. SEnvDoExecute() takes the (EFI_HANDLE*), and passes it directly --
+ // without de-referencing -- to the HandleProtocol() boot service.
+ // 5. But HandleProtocol() takes an EFI_HANDLE.
+ //
+ // Therefore we must
+ // - de-reference "ParentHandle" here, to mask the bug in
+ // SEnvDoExecute(), and
+ // - pass the resultant EFI_HANDLE as an (EFI_HANDLE*).
+ //
+ CmdStatus = (mEfiShellEnvironment2->Execute((EFI_HANDLE *)*ParentHandle,
CommandLine,
Output));
//
--
2.19.1.3.g30247aa5d201
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#47419): https://edk2.groups.io/g/devel/message/47419
Mute This Topic: https://groups.io/mt/34180236/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-
