// Searches for predetermined patterns discovered through debugging
// in the file_data (of Engine.dll), and replaces them with new values
// to provide the changed physics behaviour
// The patterns and replacements are all defined in pattern.h
bool PatchMemory(PBYTE file_data, const size_t file_size, PatchType type) {
// Find the file position of the y force pattern
size_t up_match = PatternSearch(file_data, file_size, kUpForce,
sizeof(kUpForce), kUpForceMask);
// Find the file position of the physics cap pattern
size_t cap_match = PatternSearch(file_data, file_size, kForceCap,
sizeof(kForceCap), kForceCapMask);
if (!up_match || !cap_match) {
return false;
}
// memcpy is called with search patterns instead of predefined replacements
// when it makes sense to ensure memory blocks are at their default values
switch (type) {
case kSuperRocketRagdolls:
memcpy(file_data+up_match, kUpForceRocket,
sizeof(kUpForceRocket));
memcpy(file_data+cap_match, kForceCapRocket,
sizeof(kForceCapRocket));
break;
case kSuperFlyingBodies:
memcpy(file_data+up_match, kUpForce,
sizeof(kUpForce));
memcpy(file_data+cap_match, kForceCapSuperFlying,
sizeof(kForceCapSuperFlying));
break;
case kLesserFlyingBodies:
memcpy(file_data+up_match, kUpForce,
sizeof(kUpForce));
memcpy(file_data+cap_match, kForceCapLesserFlying,
sizeof(kForceCapLesserFlying));
break;
case kOriginal:
memcpy(file_data+up_match, kUpForce,
sizeof(kUpForce));
memcpy(file_data+cap_match, kForceCap,
sizeof(kForceCap));
break;
default:
return false;
break;
}
return true;
}
void* PatternSearchModule(module_info_t* module, const char* pattern, const char* mask) {
void* res = NULL;
for (int i = 0; i < module->entries; i++) {
if (!(module->permissions[i] & PG_READ)) continue;
size_t size = module->address_end[i] - module->address_start[i];
res = PatternSearch((void*)module->address_start[i], size, pattern, mask);
if (res) break;
}
return res;
}
// NOTE: Some functions can easily and reliably be found on the VM_Call table instead.
void SearchVmFunctions(void) {
int failed = 0;
// For some reason, the module doesn't show up when reading /proc/self/maps.
// Perhaps this needs to be called later? In any case, we know exactly where
// the module is mapped, so I think this is fine. If it ever breaks, it'll
// be trivial to fix.
G_AddEvent = (G_AddEvent_ptr)PatternSearch((void*)((pint)qagame + 0xB000), 0xB0000, PTRN_G_ADDEVENT, MASK_G_ADDEVENT);
if (G_AddEvent == NULL) {
DebugPrint("ERROR: Unable to find G_AddEvent.\n");
failed = 1;
}
else DebugPrint("G_AddEvent: %p\n", G_AddEvent);
CheckPrivileges = (CheckPrivileges_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_CHECKPRIVILEGES, MASK_CHECKPRIVILEGES);
if (CheckPrivileges == NULL) {
DebugPrint("ERROR: Unable to find CheckPrivileges.\n");
failed = 1;
}
else DebugPrint("CheckPrivileges: %p\n", CheckPrivileges);
ClientConnect = (ClientConnect_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_CLIENTCONNECT, MASK_CLIENTCONNECT);
if (ClientConnect == NULL) {
DebugPrint("ERROR: Unable to find ClientConnect.\n");
failed = 1;
}
else DebugPrint("ClientConnect: %p\n", ClientConnect);
ClientSpawn = (ClientSpawn_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_CLIENTSPAWN, MASK_CLIENTSPAWN);
if (ClientSpawn == NULL) {
DebugPrint("ERROR: Unable to find ClientSpawn.\n");
failed = 1;
}
else DebugPrint("ClientSpawn: %p\n", ClientSpawn);
G_Damage = (G_Damage_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_G_DAMAGE, MASK_G_DAMAGE);
if (G_Damage == NULL) {
DebugPrint("ERROR: Unable to find G_Damage.\n");
failed = 1;
}
else DebugPrint("G_Damage: %p\n", G_Damage);
Touch_Item = (Touch_Item_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_TOUCH_ITEM, MASK_TOUCH_ITEM);
if (Touch_Item == NULL) {
DebugPrint("ERROR: Unable to find Touch_Item.\n");
failed = 1;
}
else DebugPrint("Touch_Item: %p\n", Touch_Item);
LaunchItem = (LaunchItem_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_LAUNCHITEM, MASK_LAUNCHITEM);
if (LaunchItem == NULL) {
DebugPrint("ERROR: Unable to find LaunchItem.\n");
failed = 1;
}
else DebugPrint("LaunchItem: %p\n", LaunchItem);
Drop_Item = (Drop_Item_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_DROP_ITEM, MASK_DROP_ITEM);
if (Drop_Item == NULL) {
DebugPrint("ERROR: Unable to find Drop_Item.\n");
failed = 1;
}
else DebugPrint("Drop_Item: %p\n", Drop_Item);
G_StartKamikaze = (G_StartKamikaze_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_G_STARTKAMIKAZE, MASK_G_STARTKAMIKAZE);
if (G_StartKamikaze == NULL) {
DebugPrint("ERROR: Unable to find G_StartKamikaze.\n");
failed = 1;
}
else DebugPrint("G_StartKamikaze: %p\n", G_StartKamikaze);
G_FreeEntity = (G_FreeEntity_ptr)PatternSearch((void*)((pint)qagame + 0xB000),
0xB0000, PTRN_G_FREEENTITY, MASK_G_FREEENTITY);
if (G_FreeEntity == NULL) {
DebugPrint("ERROR: Unable to find G_FreeEntity.\n");
failed = 1;
}
else DebugPrint("G_FreeEntity: %p\n", G_FreeEntity);
//bg_itemlist = qagame + 0x2CB8A0;
bg_itemlist = (gitem_t*)PatternSearch((void*)((pint)qagame + 0x2CB000),
0xB0000, PTRN_BG_ITEMLIST, MASK_BG_ITEMLIST);
if (bg_itemlist == NULL) {
DebugPrint("ERROR: Unable to find bg_itemlist.\n");
failed = 1;
}
else {
DebugPrint("bg_itemlist: %p\n", bg_itemlist);
for (bg_numItems = 1; bg_itemlist[ bg_numItems ].classname; bg_numItems++);
DebugPrint("bg_numItems: %d\n", bg_numItems);
}
if (failed) {
DebugPrint("Exiting.\n");
exit(1);
}
}
