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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "sci/sci.h"
#include "sci/engine/script.h"
#include "common/util.h"
namespace Sci {
#define PATCH_END 0xFFFF
#define PATCH_ADDTOOFFSET 0x8000
#define PATCH_GETORIGINALBYTE 0x4000
#define PATCH_MAGICDWORD(a, b, c, d) CONSTANT_LE_32(a | (b << 8) | (c << 16) | (d << 24))
struct SciScriptSignature {
uint16 scriptNr;
const char *description;
uint32 magicDWord;
int magicOffset;
const byte *data;
const uint16 *patch;
};
// signatures are built like this:
// - first a counter of the bytes that follow
// - then the actual bytes that need to get matched
// - then another counter of bytes (0 for EOS)
// - if not EOS, an adjust offset and the actual bytes
// - rinse and repeat
// this here gets called on entry and when going out of game windows
// uEvt::port will not get changed after kDisposeWindow but a bit later, so
// we would get an invalid port handle to a kSetPort call. We just patch in
// resetting of the port selector. We destroy the stop/fade code in there,
// it seems it isn't used at all in the game.
const byte hoyle4SignaturePortFix[] = {
28,
0x39, 0x09, // pushi 09
0x89, 0x0b, // lsg 0b
0x39, 0x64, // pushi 64
0x38, 0xc8, 0x00, // pushi 00c8
0x38, 0x2c, 0x01, // pushi 012c
0x38, 0x90, 0x01, // pushi 0190
0x38, 0xf4, 0x01, // pushi 01f4
0x38, 0x58, 0x02, // pushi 0258
0x38, 0xbc, 0x02, // pushi 02bc
0x38, 0x20, 0x03, // pushi 0320
0x46, // calle [xxxx] [xxxx] [xx]
+5, 43, // [skip 5 bytes]
0x30, 0x27, 0x00, // bnt 0027 -> end of routine
0x87, 0x00, // lap 00
0x30, 0x19, 0x00, // bnt 0019 -> fade out
0x87, 0x01, // lap 01
0x30, 0x14, 0x00, // bnt 0014 -> fade out
0x38, 0xa7, 0x00, // pushi 00a7
0x76, // push0
0x80, 0x29, 0x01, // lag 0129
0x4a, 0x04, // send 04 (song::stop)
0x39, 0x27, // pushi 27
0x78, // push1
0x8f, 0x01, // lsp 01
0x51, 0x54, // class 54
0x4a, 0x06, // send 06 (PlaySong::play)
0x33, 0x09, // jmp 09 -> end of routine
0x38, 0xaa, 0x00, // pushi 00aa
0x76, // push0
0x80, 0x29, 0x01, // lag 0129
0x4a, 0x04, // send 04
0x48, // ret
0
};
const uint16 hoyle4PatchPortFix[] = {
PATCH_ADDTOOFFSET | +33,
0x38, 0x31, 0x01, // pushi 0131 (selector curEvent)
0x76, // push0
0x80, 0x50, 0x00, // lag 0050 (global var 80h, "User")
0x4a, 0x04, // send 04 (read User::curEvent)
0x38, 0x93, 0x00, // pushi 0093 (selector port)
0x78, // push1
0x76, // push0
0x4a, 0x06, // send 06 (write 0 to that object::port)
0x48, // ret
PATCH_END
};
// script, description, magic DWORD, adjust
const SciScriptSignature hoyle4Signatures[] = {
{ 0, "port fix when disposing windows", PATCH_MAGICDWORD(0x64, 0x38, 0xC8, 0x00), -5, hoyle4SignaturePortFix, hoyle4PatchPortFix },
{ 0, NULL, 0, 0, NULL, NULL }
};
// this is called on every death dialog. Problem is at least the german
// version of lsl6 gets title text that is far too long for the
// available temp space resulting in temp space corruption
// This patch moves the title text around, so this overflow
// doesn't happen anymore. We would otherwise get a crash
// calling for invalid views (this happens of course also
// in sierra sci)
const byte larry6SignatureDeathDialog[] = {
7,
0x3e, 0x33, 0x01, // link 0133 (offset 0x20)
0x35, 0xff, // ldi ff
0xa3, 0x00, // sal 00
+255, 0,
+255, 0,
+170, 12, // [skip 680 bytes]
0x8f, 0x01, // lsp 01 (offset 0x2cf)
0x7a, // push2
0x5a, 0x04, 0x00, 0x0e, 0x01, // lea 0004 010e
0x36, // push
0x43, 0x7c, 0x0e, // kMessage[7c] 0e
+90, 10, // [skip 90 bytes]
0x38, 0xd6, 0x00, // pushi 00d6 (offset 0x335)
0x78, // push1
0x5a, 0x04, 0x00, 0x0e, 0x01, // lea 0004 010e
0x36, // push
+76, 11, // [skip 76 bytes]
0x38, 0xcd, 0x00, // pushi 00cd (offset 0x38b)
0x39, 0x03, // pushi 03
0x5a, 0x04, 0x00, 0x0e, 0x01, // lea 0004 010e
0x36,
0
};
const uint16 larry6PatchDeathDialog[] = {
0x3e, 0x00, 0x02, // link 0200
PATCH_ADDTOOFFSET | +687,
0x5a, 0x04, 0x00, 0x40, 0x01, // lea 0004 0140
PATCH_ADDTOOFFSET | +98,
0x5a, 0x04, 0x00, 0x40, 0x01, // lea 0004 0140
PATCH_ADDTOOFFSET | +82,
0x5a, 0x04, 0x00, 0x40, 0x01, // lea 0004 0140
PATCH_END
};
// script, description, magic DWORD, adjust
const SciScriptSignature larry6Signatures[] = {
{ 82, "death dialog memory corruption", PATCH_MAGICDWORD(0x3e, 0x33, 0x01, 0x35), 0, larry6SignatureDeathDialog, larry6PatchDeathDialog },
{ 0, NULL, 0, 0, NULL, NULL }
};
// will actually patch previously found signature area
void Script::applyPatch(const uint16 *patch, byte *scriptData, const uint32 scriptSize, int32 signatureOffset) {
int32 offset = signatureOffset;
uint16 patchWord = *patch;
while (patchWord != PATCH_END) {
if (patchWord & PATCH_ADDTOOFFSET) {
offset += patchWord & ~PATCH_ADDTOOFFSET;
} else if (patchWord & PATCH_GETORIGINALBYTE) {
// TODO: implement this
} else {
scriptData[offset] = patchWord & 0xFF;
offset++;
}
patch++;
patchWord = *patch;
}
}
// will return -1 if no match was found, otherwise an offset to the start of the signature match
int32 Script::findSignature(const SciScriptSignature *signature, const byte *scriptData, const uint32 scriptSize) {
if (scriptSize < 4) // we need to find a DWORD, so less than 4 bytes is not okay
return -1;
const uint32 magicDWord = signature->magicDWord; // is platform-specific BE/LE form, so that the later match will work
const uint32 searchLimit = scriptSize - 3;
uint32 DWordOffset = 0;
// first search for the magic DWORD
while (DWordOffset < searchLimit) {
if (magicDWord == *(const uint32 *)(scriptData + DWordOffset)) {
// magic DWORD found, check if actual signature matches
uint32 offset = DWordOffset + signature->magicOffset;
uint32 byteOffset = offset;
const byte *signatureData = signature->data;
byte matchAdjust = 1;
while (matchAdjust) {
byte matchBytesCount = *signatureData++;
if ((byteOffset + matchBytesCount) > scriptSize) // Out-Of-Bounds?
break;
if (memcmp(signatureData, &scriptData[byteOffset], matchBytesCount)) // Byte-Mismatch?
break;
// those bytes matched, adjust offsets accordingly
signatureData += matchBytesCount;
byteOffset += matchBytesCount;
// get offset...
matchAdjust = *signatureData++;
byteOffset += matchAdjust;
}
if (!matchAdjust) // all matches worked?
return offset;
}
DWordOffset++;
}
// nothing found
return -1;
}
void Script::matchSignatureAndPatch(uint16 scriptNr, byte *scriptData, const uint32 scriptSize) {
const SciScriptSignature *signatureTable = NULL;
if (g_sci->getGameId() == GID_HOYLE4)
signatureTable = hoyle4Signatures;
if (g_sci->getGameId() == GID_LSL6)
signatureTable = larry6Signatures;
if (signatureTable) {
while (signatureTable->data) {
if (scriptNr == signatureTable->scriptNr) {
int32 foundOffset = findSignature(signatureTable, scriptData, scriptSize);
if (foundOffset != -1) {
// found, so apply the patch
warning("matched %s on script %d offset %d", signatureTable->description, scriptNr, foundOffset);
applyPatch(signatureTable->patch, scriptData, scriptSize, foundOffset);
}
}
signatureTable++;
}
}
}
} // End of namespace Sci
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