/*++
Copyright (c) 1990 Microsoft Corporation
Module Name:
jumps.c
Abstract:
This module implements the C runtime library functions for set jump and
long jump that are compatible with structured exception handling.
Author:
David N. Cutler (davec) 15-Sep-1990
Environment:
Any mode.
Revision History:
Tom Wood 23-Aug-1994
Add stack limit parameters to RtlVirtualUnwind.
--*/
#include "ntrtlp.h"
#include "setjmp.h"
VOID
longjmp (
IN jmp_buf JumpBuffer,
IN int ReturnValue
)
/*++
Routine Description:
This function executes a long jump operation by virtually unwinding to
the caller of the corresponding call to set jump and then calling unwind
to transfer control to the jump target.
Arguments:
JumpBuffer - Supplies the address of a jump buffer that contains the
virtual frame pointer and target address.
N.B. This is an array of double to force quadword alignment.
ReturnValue - Supplies the value that is to be returned to the caller
of set jump.
Return Value:
None.
--*/
{
PULONG JumpArray;
//
// If the specified return value is zero, then set it to one.
//
if (ReturnValue == 0) {
ReturnValue = 1;
}
//
// Unwind to the caller of set jump and return the specified value.
// There is no return from unwind.
//
JumpArray = (PULONG)&JumpBuffer[0];
RtlUnwind((PVOID)JumpArray[0],
(PVOID)JumpArray[1],
NULL,
(PVOID)ReturnValue);
}
int
setjmp (
IN jmp_buf JumpBuffer
)
/*++
Routine Description:
This function performs a set jump operation by capturing the current
context, virtualy unwinding to the caller of set jump, and returns zero
to the caller.
Arguments:
JumpBuffer - Supplies the address of a jump buffer to store the virtual
frame pointer and target address of the caller.
N.B. This is an array of double to force quadword alignment.
Return Value:
A value of zero is returned.
--*/
{
CONTEXT ContextRecord;
ULONG EstablisherFrame;
PRUNTIME_FUNCTION FunctionEntry;
BOOLEAN InFunction;
PULONG JumpArray;
ULONG NextPc;
//
// Capture the current context, virtually unwind to the caller of set
// jump, and return zero to the caller.
//
JumpArray = (PULONG)&JumpBuffer[0];
RtlCaptureContext(&ContextRecord);
NextPc = ContextRecord.Lr - 4;
FunctionEntry = RtlLookupFunctionEntry(NextPc);
NextPc = RtlVirtualUnwind(NextPc,
FunctionEntry,
&ContextRecord,
&InFunction,
&EstablisherFrame,
NULL,
0,
0xffffffff);
JumpArray[1] = NextPc + 4;
FunctionEntry = RtlLookupFunctionEntry(NextPc);
NextPc = RtlVirtualUnwind(NextPc,
FunctionEntry,
&ContextRecord,
&InFunction,
&EstablisherFrame,
NULL,
0,
0xffffffff);
JumpArray[0] = EstablisherFrame;
return 0;
}
