From 06ffc9beb27a82dea25bb4cd3825ea3b57df5df5 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Wed, 26 Apr 2017 14:20:30 +0200
Subject: [PATCH 1/2] ShellPkg/Shell: clean up bogus member types in SPLIT_LIST
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Message-id: <20170426122031.12047-2-lersek@redhat.com>
Patchwork-id: 74883
O-Subject: [RHEL-7.4 ovmf PATCH 1/2] ShellPkg/Shell: clean up bogus member types
in SPLIT_LIST
Bugzilla: 1442908
Acked-by: Thomas Huth <thuth@redhat.com>
Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
The "SPLIT_LIST.SplitStdOut" and "SPLIT_LIST.SplitStdIn" members currently
have type (SHELL_FILE_HANDLE *). This is wrong; SHELL_FILE_HANDLE is
already a pointer, there's no need to store a pointer to a pointer.
The error is obvious if we check where and how these members are used:
- In the RunSplitCommand() function, these members are used (populated)
extensively; this function has to be updated in sync.
ConvertEfiFileProtocolToShellHandle() already returns the temporary
memory file created with CreateFileInterfaceMem() as SHELL_FILE_HANDLE,
not as (SHELL_FILE_HANDLE *).
- In particular, the ConvertShellHandleToEfiFileProtocol() calls need to
be dropped as well in RunSplitCommand(), since
EFI_SHELL_PROTOCOL.SetFilePosition() and EFI_SHELL_PROTOCOL.CloseFile()
take SHELL_FILE_HANDLE parameters, not (EFI_FILE_PROTOCOL *).
Given that ConvertShellHandleToEfiFileProtocol() only performs a
type-cast (it does not adjust any pointer values), *and*
SHELL_FILE_HANDLE -- taken by EFI_SHELL_PROTOCOL member functions -- is
actually a typedef to (VOID *) -- see more on this later --, this
conversion error hasn't been caught by compilers.
- In the ProcessNewSplitCommandLine() function, RunSplitCommand() is
called either initially (passing in NULL / NULL; no update needed), or
recursively (passing in Split->SplitStdIn / Split->SplitStdOut; again no
update is necessary beyond the RunSplitCommand() modification above).
- In the UpdateStdInStdOutStdErr() and RestoreStdInStdOutStdErr()
functions, said structure members are compared and assigned to
"EFI_SHELL_PARAMETERS_PROTOCOL.StdIn" and
"EFI_SHELL_PARAMETERS_PROTOCOL.StdOut", both of which have type
SHELL_FILE_HANDLE, *not* (SHELL_FILE_HANDLE *).
The compiler hasn't caught this error because of the fatally flawed type
definition of SHELL_FILE_HANDLE, namely
typedef VOID *SHELL_FILE_HANDLE;
Pointer-to-void silently converts to and from most other pointer types;
among them, pointer-to-pointer-to-void. That is also why no update is
necessary for UpdateStdInStdOutStdErr() and RestoreStdInStdOutStdErr()
in this fix.
(
Generally speaking, using (VOID *) typedefs for opaque handles is a tragic
mistake in all of the UEFI-related specifications; this practice defeats
any type checking that compilers might help programmers with. The right
way to define an opaque handle is as follows:
//
// Introduce the incomplete structure type, and the derived pointer
// type, in both the specification and the public edk2 headers. Note
// that the derived pointer type itself is a complete type, and it can
// be used freely by client code.
//
typedef struct SHELL_FILE *SHELL_FILE_HANDLE;
//
// Complete the structure type in the edk2 internal C source files.
//
struct SHELL_FILE {
//
// list fields
//
};
This way the structure size and members remain hidden from client code,
but the C compiler can nonetheless catch any invalid conversions between
incompatible XXX_HANDLE types.
)
Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Marvin Häuser <Marvin.Haeuser@outlook.com>
Cc: Qiu Shumin <shumin.qiu@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
(cherry picked from commit 1bd0bf153ebf4993421afd5084c52a6e57e17fdc)
---
ShellPkg/Application/Shell/Shell.c | 12 ++++++------
ShellPkg/Application/Shell/Shell.h | 4 ++--
2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/ShellPkg/Application/Shell/Shell.c b/ShellPkg/Application/Shell/Shell.c
index 731ba18..816dd1a 100644
--- a/ShellPkg/Application/Shell/Shell.c
+++ b/ShellPkg/Application/Shell/Shell.c
@@ -1705,8 +1705,8 @@ ShellConvertVariables (
EFI_STATUS
RunSplitCommand(
IN CONST CHAR16 *CmdLine,
- IN SHELL_FILE_HANDLE *StdIn,
- IN SHELL_FILE_HANDLE *StdOut
+ IN SHELL_FILE_HANDLE StdIn,
+ IN SHELL_FILE_HANDLE StdOut
)
{
EFI_STATUS Status;
@@ -1715,7 +1715,7 @@ RunSplitCommand(
UINTN Size1;
UINTN Size2;
SPLIT_LIST *Split;
- SHELL_FILE_HANDLE *TempFileHandle;
+ SHELL_FILE_HANDLE TempFileHandle;
BOOLEAN Unicode;
ASSERT(StdOut == NULL);
@@ -1781,7 +1781,7 @@ RunSplitCommand(
Split->SplitStdOut = Split->SplitStdIn;
}
Split->SplitStdIn = TempFileHandle;
- ShellInfoObject.NewEfiShellProtocol->SetFilePosition(ConvertShellHandleToEfiFileProtocol(Split->SplitStdIn), 0);
+ ShellInfoObject.NewEfiShellProtocol->SetFilePosition (Split->SplitStdIn, 0);
if (!EFI_ERROR(Status)) {
Status = RunCommand(NextCommandLine);
@@ -1797,10 +1797,10 @@ RunSplitCommand(
// Note that the original StdIn is now the StdOut...
//
if (Split->SplitStdOut != NULL) {
- ShellInfoObject.NewEfiShellProtocol->CloseFile(ConvertShellHandleToEfiFileProtocol(Split->SplitStdOut));
+ ShellInfoObject.NewEfiShellProtocol->CloseFile (Split->SplitStdOut);
}
if (Split->SplitStdIn != NULL) {
- ShellInfoObject.NewEfiShellProtocol->CloseFile(ConvertShellHandleToEfiFileProtocol(Split->SplitStdIn));
+ ShellInfoObject.NewEfiShellProtocol->CloseFile (Split->SplitStdIn);
FreePool (Split->SplitStdIn);
}
diff --git a/ShellPkg/Application/Shell/Shell.h b/ShellPkg/Application/Shell/Shell.h
index 25ac114..ff08494 100644
--- a/ShellPkg/Application/Shell/Shell.h
+++ b/ShellPkg/Application/Shell/Shell.h
@@ -63,8 +63,8 @@ extern CONST CHAR16 mNoNestingFalse[];
typedef struct {
LIST_ENTRY Link; ///< Standard linked list handler.
- SHELL_FILE_HANDLE *SplitStdOut; ///< ConsoleOut for use in the split.
- SHELL_FILE_HANDLE *SplitStdIn; ///< ConsoleIn for use in the split.
+ SHELL_FILE_HANDLE SplitStdOut; ///< ConsoleOut for use in the split.
+ SHELL_FILE_HANDLE SplitStdIn; ///< ConsoleIn for use in the split.
} SPLIT_LIST;
typedef struct {
--
1.8.3.1