Fix broken GetInputDeviceManager signature (#972)

Dalamud.Boot/utils.cpp

@@ -348,6 +348,27 @@ utils::signature_finder& utils::signature_finder::look_for_hex(std::string_view
     return *this;
 }
 
+const char* utils::signature_finder::result::resolve_jump_target(size_t instructionOffset) const {
+    nmd_x86_instruction instruction{};
+    if (!nmd_x86_decode(&Match[instructionOffset], NMD_X86_MAXIMUM_INSTRUCTION_LENGTH, &instruction, NMD_X86_MODE_64, NMD_X86_DECODER_FLAGS_ALL))
+        throw std::runtime_error("Matched address does not have a valid assembly instruction");
+    
+    size_t numExplicitOperands = 0;
+    for (size_t i = 0; i < instruction.num_operands; i++)
+        numExplicitOperands += instruction.operands[i].is_implicit ? 0 : 1;
+    if (numExplicitOperands != 1)
+        throw std::runtime_error("Number of operands at the instruction at matched address is not 1");
+
+    if (!(instruction.group & NMD_GROUP_CALL) && !(instruction.group & NMD_GROUP_JUMP))
+        throw std::runtime_error("The instruction at matched address is not a call or jump instruction");
+
+    const auto& arg1 = instruction.operands[0];
+    if (arg1.type != NMD_X86_OPERAND_TYPE_IMMEDIATE)
+        throw std::runtime_error("The first operand for the instruction at matched address is not an immediate value");
+
+    return &Match[instructionOffset] + instruction.length + arg1.fields.imm;
+}
+
 std::vector<utils::signature_finder::result> utils::signature_finder::find(size_t minCount, size_t maxCount, bool bErrorOnMoreThanMaximum) const {
     std::vector<result> res;
 
@@ -383,8 +404,8 @@ std::vector<utils::signature_finder::result> utils::signature_finder::find(size_
     return res;
 }
 
-std::span<const char> utils::signature_finder::find_one() const {
-    return find(1, 1, false).front().Match;
+utils::signature_finder::result utils::signature_finder::find_one() const {
+    return find(1, 1, false).front();
 }
 
 utils::memory_tenderizer::memory_tenderizer(const void* pAddress, size_t length, DWORD dwNewProtect) : m_data(reinterpret_cast<char*>(const_cast<void*>(pAddress)), length) {

Dalamud.Boot/utils.h

@@ -96,11 +96,18 @@ namespace utils {
             size_t PatternIndex;
             size_t MatchIndex;
             size_t CaptureIndex;
+
+            const char* resolve_jump_target(size_t instructionOffset = 0) const;
+
+            template<typename T>
+            T resolve_jump_target(size_t instructionOffset = 0) const {
+                return reinterpret_cast<T>(const_cast<char*>(resolve_jump_target(instructionOffset)));
+            }
         };
 
         std::vector<result> find(size_t minCount, size_t maxCount, bool bErrorOnMoreThanMaximum) const;
 
-        std::span<const char> find_one() const;
+        result find_one() const;
     };
 
     class memory_tenderizer {

Dalamud.Boot/xivfixes.cpp

@@ -169,26 +169,11 @@ static TFnGetInputDeviceManager* GetGetInputDeviceManager(HWND hwnd) {
     if (pCached)
         return pCached;
 
-    char szClassName[256];
-    GetClassNameA(hwnd, szClassName, static_cast<int>(sizeof szClassName));
-
-    WNDCLASSEXA wcx{};
-    GetClassInfoExA(g_hGameInstance, szClassName, &wcx);
-    const auto match = utils::signature_finder()
+    return pCached = utils::signature_finder()
         .look_in(utils::loaded_module(g_hGameInstance), ".text")
-        .look_for_hex("41 81 fe 19 02 00 00 0f 87 ?? ?? 00 00 0f 84 ?? ?? 00 00")
-        .find_one();
-
-    auto ptr = match.data() + match.size() + *reinterpret_cast<const int*>(match.data() + match.size() - 4);
-    ptr += 4;  // CMP RBX, 0x7
-    ptr += 2;  // JNZ <giveup>
-    ptr += 7;  // MOV RCX, <Framework::Instance>
-    ptr += 3;  // TEST RCX, RCX
-    ptr += 2;  // JZ <giveup>
-    ptr += 5;  // CALL <GetInputDeviceManagerInstance()>
-    ptr += *reinterpret_cast<const int*>(ptr - 4);
-
-    return pCached = reinterpret_cast<TFnGetInputDeviceManager*>(ptr);
+        .look_for_hex("e8 ?? ?? ?? ?? 48 8b 58 10 48 85 db")
+        .find_one()
+        .resolve_jump_target<TFnGetInputDeviceManager*>();
 }
 
 void xivfixes::prevent_devicechange_crashes(bool bApply) {
@@ -202,9 +187,13 @@ void xivfixes::prevent_devicechange_crashes(bool bApply) {
     static const auto s_pfnBinder = static_cast<WNDPROC>(VirtualAlloc(nullptr, 64, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE));
     static const auto s_pfnAlternativeWndProc = static_cast<WNDPROC>([](HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) -> LRESULT {
         if (uMsg == WM_DEVICECHANGE && wParam == DBT_DEVNODES_CHANGED) {
-            if (!GetGetInputDeviceManager(hWnd)()) {
-                logging::I("{} WndProc(0x{:X}, WM_DEVICECHANGE, DBT_DEVNODES_CHANGED, {}) called but the game does not have InputDeviceManager initialized; doing nothing.", LogTag, reinterpret_cast<size_t>(hWnd), lParam);
-                return 0;
+            try {
+                if (!GetGetInputDeviceManager(hWnd)()) {
+                    logging::I("{} WndProc(0x{:X}, WM_DEVICECHANGE, DBT_DEVNODES_CHANGED, {}) called but the game does not have InputDeviceManager initialized; doing nothing.", LogTag, reinterpret_cast<size_t>(hWnd), lParam);
+                    return 0;
+                }
+            } catch (const std::exception& e) {
+                logging::W("{} WndProc(0x{:X}, WM_DEVICECHANGE, DBT_DEVNODES_CHANGED, {}) called, but failed to resolve address for GetInputDeviceManager: {}", LogTag, reinterpret_cast<size_t>(hWnd), lParam, e.what());
             }
         }