static bool SafeWriteJump_Internal(uintptr_t src, uintptr_t dst, UInt8 op)
{
#pragma pack(push, 1)
struct Code
{
UInt8 op;
SInt32 displ;
};
#pragma pack(pop)
STATIC_ASSERT(sizeof(Code) == 5);
ptrdiff_t delta = dst - (src + sizeof(Code));
if((delta < INT_MIN) || (delta > INT_MAX))
return false;
Code code;
code.op = op;
code.displ = delta;
SafeWriteBuf(src, &code, sizeof(code));
return true;
}
static void FixErrorReportBug(void)
{
// bethesda passes strings containing user input to printf-like functions
// this causes crashes when the user input contains tokens printf is interested in
// so we fix it
// move the entire block of code before the call to printf down, add a new argument pointing to "%s"
const UInt32 kBlockMoveDelta = 5;
#error const UInt32 kBlockMoveSrc = 0x00500001; // inside ShowCompilerError, one past last referebnce
#error const UInt32 kBlockMoveDst = kBlockMoveSrc + kBlockMoveDelta;
#error const UInt32 kBlockMoveSize = 0x00500035 - kBlockMoveSrc;
#error const UInt32 kFormatStrPos = 0x0092BBE4; // "%s"
#error const UInt32 kStackFixupPos = 0x0B + 2;
#error const UInt32 kPCRelFixups[] = { 0x00 + 1, 0x06 + 1, 0x28 + 1 };
UInt8 tempBuf[kBlockMoveSize];
memcpy(tempBuf, (void *)kBlockMoveSrc, kBlockMoveSize);
// jumps/calls are pc-relative, we're moving code so fix them up
*((UInt32 *)&tempBuf[kPCRelFixups[0]]) -= kBlockMoveDelta;
*((UInt32 *)&tempBuf[kPCRelFixups[1]]) -= kBlockMoveDelta;
*((UInt32 *)&tempBuf[kPCRelFixups[2]]) -= kBlockMoveDelta;
// added a new arg, so we need to clean it off the stack
tempBuf[kStackFixupPos] += 4;
SafeWriteBuf(kBlockMoveDst, tempBuf, kBlockMoveSize);
SafeWrite8(kBlockMoveSrc + 0, 0x68); // push "%s"
SafeWrite32(kBlockMoveSrc + 1, kFormatStrPos);
}
void xEdit_ObScript_Commit()
{
ObScriptCommand cmd = *s_hijackedCommand;
cmd.longName = xEditCommandName;
cmd.shortName = "";
cmd.helpText = "";
cmd.needsParent = 0;
cmd.numParams = 0;
cmd.execute = xEditCommand_Execute;
cmd.flags = 0;
SafeWriteBuf((uintptr_t)s_hijackedCommand, &cmd, sizeof(cmd));
_MESSAGE("xEdit console command '%s' installed as 0x%08x", cmd.longName, cmd.opcode);
}
void SafeWrite64(uintptr_t addr, UInt64 data)
{
SafeWriteBuf(addr, &data, sizeof(data));
}
void SafeWrite32(uintptr_t addr, UInt32 data)
{
SafeWriteBuf(addr, &data, sizeof(data));
}
void SafeWrite16(uintptr_t addr, UInt16 data)
{
SafeWriteBuf(addr, &data, sizeof(data));
}