Merge pull request #3294 from Sonicadvance1/mov_xid_check

FEXCore: Moves XID check to the frontend

FEXCore/Source/Interface/Context/Context.h

@@ -250,7 +250,6 @@ namespace FEXCore::Context {
     FEXCore::Core::InternalThreadState* ParentThread{};
     fextl::vector<FEXCore::Core::InternalThreadState*> Threads;
     std::atomic_bool CoreShuttingDown{false};
-    bool NeedToCheckXID{true};
 
     std::mutex IdleWaitMutex;
     std::condition_variable IdleWaitCV;

FEXCore/Source/Interface/Core/Core.cpp

@@ -528,21 +528,10 @@ namespace FEXCore::Context {
     ExecutionThreadHandler *Arg = reinterpret_cast<ExecutionThreadHandler*>(FEXCore::Allocator::malloc(sizeof(ExecutionThreadHandler)));
     Arg->This = this;
     Arg->Thread = Thread;
-    Thread->StartPaused = NeedToCheckXID;
     Thread->ExecutionThread = FEXCore::Threads::Thread::Create(ThreadHandler, Arg);
 
     // Wait for the thread to have started
     Thread->ThreadWaiting.Wait();
-
-    if (NeedToCheckXID) {
-      // The first time an application creates a thread, GLIBC installs their SETXID signal handler.
-      // FEX needs to capture all signals and defer them to the guest.
-      // Once FEX creates its first guest thread, overwrite the GLIBC SETXID handler *again* to ensure
-      // FEX maintains control of the signal handler on this signal.
-      NeedToCheckXID = false;
-      SignalDelegation->CheckXIDHandler();
-      Thread->StartRunning.NotifyAll();
-    }
   }
 
   void ContextImpl::InitializeThreadTLSData(FEXCore::Core::InternalThreadState *Thread) {

FEXCore/include/FEXCore/Core/SignalDelegator.h

@@ -47,14 +47,6 @@ namespace Core {
     virtual void RegisterTLSState(FEXCore::Core::InternalThreadState *Thread) = 0;
     virtual void UninstallTLSState(FEXCore::Core::InternalThreadState *Thread) = 0;
 
-    /**
-     * @brief Check to ensure the XID handler is still set to the FEX handler
-     *
-     * On a new thread GLIBC will set the XID handler underneath us.
-     * After the first thread is created check this.
-     */
-    virtual void CheckXIDHandler() = 0;
-
     struct SignalDelegatorConfig {
       bool StaticRegisterAllocation{};
       bool SupportsAVX{};

Source/Tools/CommonTools/DummyHandlers.h

@@ -25,8 +25,6 @@ class DummySyscallHandler: public FEXCore::HLE::SyscallHandler, public FEXCore::
 
 class DummySignalDelegator final : public FEXCore::SignalDelegator, public FEXCore::Allocator::FEXAllocOperators {
   public:
-  void CheckXIDHandler() override {}
-
   void SignalThread(FEXCore::Core::InternalThreadState *Thread, FEXCore::Core::SignalEvent Event) override {}
 
   FEXCore::Core::InternalThreadState *GetBackingTLSThread() {

Source/Tools/FEXLoader/LinuxSyscalls/SignalDelegator.h

@@ -89,7 +89,13 @@ namespace FEX::HLE {
       uint64_t GuestSignalFD(int fd, const uint64_t *set, size_t sigsetsize , int flags);
     /**  @} */
 
-      void CheckXIDHandler() override;
+    /**
+     * @brief Check to ensure the XID handler is still set to the FEX handler
+     *
+     * On a new thread GLIBC will set the XID handler underneath us.
+     * After the first thread is created check this.
+     */
+      void CheckXIDHandler();
 
       void UninstallHostHandler(int Signal);
       FEXCore::Context::Context *CTX;

Source/Tools/FEXLoader/LinuxSyscalls/Syscalls.h

@@ -225,6 +225,9 @@ class SyscallHandler : public FEXCore::HLE::SyscallHandler, FEXCore::HLE::Source
 
   SourcecodeResolver *GetSourcecodeResolver() override { return this; }
 
+  bool NeedXIDCheck() const { return NeedToCheckXID; }
+  void DisableXIDCheck() { NeedToCheckXID = false; }
+
 protected:
   SyscallHandler(FEXCore::Context::Context *_CTX, FEX::HLE::SignalDelegator *_SignalDelegation);
 
@@ -250,6 +253,7 @@ class SyscallHandler : public FEXCore::HLE::SyscallHandler, FEXCore::HLE::Source
   std::mutex FutexMutex;
   std::mutex SyscallMutex;
   FEXCore::CodeLoader *LocalLoader{};
+  bool NeedToCheckXID{true};
 
   #ifdef DEBUG_STRACE
     void Strace(FEXCore::HLE::SyscallArguments *Args, uint64_t Ret);

Source/Tools/FEXLoader/LinuxSyscalls/Syscalls/Thread.cpp

@@ -59,8 +59,19 @@ namespace FEX::HLE {
     }
 
     auto NewThread = CTX->CreateThread(0, 0, &NewThreadState, args->args.parent_tid);
+    bool NeedsXIDCheck = FEX::HLE::_SyscallHandler->NeedXIDCheck();
+    NewThread->StartPaused = NeedsXIDCheck;
     CTX->InitializeThread(NewThread);
 
+    if (NeedsXIDCheck) {
+      // The first time an application creates a thread, GLIBC installs their SETXID signal handler.
+      // FEX needs to capture all signals and defer them to the guest.
+      // Once FEX creates its first guest thread, overwrite the GLIBC SETXID handler *again* to ensure
+      // FEX maintains control of the signal handler on this signal.
+      FEX::HLE::_SyscallHandler->GetSignalDelegator()->CheckXIDHandler();
+      FEX::HLE::_SyscallHandler->DisableXIDCheck();
+    }
+
     if (FEX::HLE::_SyscallHandler->Is64BitMode()) {
       if (flags & CLONE_SETTLS) {
         x64::SetThreadArea(NewThread->CurrentFrame, reinterpret_cast<void*>(args->args.tls));