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[PSEH3] Fix unlinking of EH frames during unwind.

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On Windows the function that calls the language specific exception handler function registers it's own exception handler, so the top of the exception chain does not point to our own handler. We need to take that into account when unwinding the stack and removing each handler as we go.
This commit is contained in:
Timo Kreuzer 2020-03-10 22:06:19 +02:00
parent ff8d24cabb
commit cfb579dd67
1 changed files with 46 additions and 14 deletions
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60
sdk/lib/pseh/i386/pseh3.c
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@ -37,6 +37,8 @@
#include <windef.h>
#include <winnt.h>
#define ASSERT(exp) if (!(exp)) __int2c();
#include "pseh3.h"
#include "pseh3_asmdef.h"
@ -66,10 +68,49 @@ __attribute__((regparm(1)))
_SEH3$_Unregister(
volatile SEH3$_REGISTRATION_FRAME *Frame)
{
if (Frame->Handler)
_SEH3$_UnregisterFrame(Frame);
volatile SEH3$_REGISTRATION_FRAME *CurrentFrame;
/* Check if the frame has a handler (then it's the registered frame) */
if (Frame->Handler != NULL)
{
/* There shouldn't be any more nested try-level frames */
ASSERT(Frame->EndOfChain == Frame);
/* During unwinding on Windows ExecuteHandler2 installs it's own EH frame,
so there can be one or even multiple frames before our own one and we
need to search for the link that points to our head frame. */
CurrentFrame = (SEH3$_REGISTRATION_FRAME*)__readfsdword(0);
if (Frame == CurrentFrame)
{
/* The target frame is the first installed frame, remove it */
__writefsdword(0, (ULONG)Frame->Next);
return;
}
/* Loop to find the frame that links the target frame */
while (CurrentFrame->Next != Frame)
{
CurrentFrame = CurrentFrame->Next;
}
/* Remove the frame from the linked list */
CurrentFrame->Next = Frame->Next;
}
else
_SEH3$_UnregisterTryLevel(Frame);
{
/* Search for the head frame */
CurrentFrame = Frame->Next;
while (CurrentFrame->Handler == NULL)
{
CurrentFrame = CurrentFrame->Next;
}
/* Make sure the head frame points to our frame */
ASSERT(CurrentFrame->EndOfChain == Frame);
/* Remove this frame from the internal linked list */
CurrentFrame->EndOfChain = Frame->Next;
}
}
static inline
@ -146,10 +187,7 @@ __attribute__((regparm(1)))
_SEH3$_AutoCleanup(
volatile SEH3$_REGISTRATION_FRAME *Frame)
{
if (Frame->Handler)
_SEH3$_UnregisterFrame(Frame);
else
_SEH3$_UnregisterTryLevel(Frame);
_SEH3$_Unregister(Frame);
/* Check for __finally frames */
if (Frame->ScopeTable->Target == NULL)
@ -167,12 +205,6 @@ _SEH3$_GetFilterResult(
PVOID Filter = Record->ScopeTable->Filter;
LONG Result;
/* Check for __finally frames */
if (Record->ScopeTable->Target == NULL)
{
return EXCEPTION_CONTINUE_SEARCH;
}
/* Check if we have a constant filter */
if (((ULONG)Filter & 0xFFFFFF00) == 0)
{
@ -278,7 +310,7 @@ _SEH3$_except_handler(
ExceptionPointers.ContextRecord = ContextRecord;
/* Check if this is an unwind */
if (ExceptionRecord->ExceptionFlags & EXCEPTION_UNWINDING)
if (IS_UNWINDING(ExceptionRecord->ExceptionFlags))
{
/* Unwind all local frames */
TargetFrame = EstablisherFrame->Next;