Adds support for guest sigprocmask

This was causing our SIGBUS handling to fail in FTL

External/FEXCore/Source/Interface/Core/SignalDelegator.cpp

@@ -21,6 +21,7 @@ namespace FEXCore {
     // Guest signal sa_mask is per thread!
     SignalDelegator::GuestSAMask Guest_sa_mask[SignalDelegator::MAX_SIGNALS]{};
     uint32_t CurrentSignal{};
+    uint64_t GuestProcMask{};
   };
 
   thread_local ThreadState ThreadData{};
@@ -94,11 +95,18 @@ namespace FEXCore {
       }
     }
 
+    // Signal specific mask check
     if (SigIsMember(&ThreadData.Guest_sa_mask[ThreadData.CurrentSignal], Signal)) {
       // If we are in a signal and our signal mask is blocking this signal then ignore it
       return;
     }
 
+    // Thread specific mask check
+    if (ThreadData.GuestProcMask & (Signal - 1)) {
+      // If the thread specific mask masks the signal then it is hidden from the guest
+      return;
+    }
+
     ThreadData.CurrentSignal = Signal;
 
     // We have an emulation thread pointer, we can now modify its state
@@ -396,4 +404,27 @@ namespace FEXCore {
     return 0;
   }
 
+  uint64_t SignalDelegator::GuestSigProcMask(int how, const uint64_t *set, uint64_t *oldset) {
+    if (!!oldset) {
+      *oldset = ThreadData.GuestProcMask;
+    }
+
+    if (!!set) {
+      uint64_t IgnoredSignalsMask = ~((1ULL << (SIGKILL - 1)) | (1ULL << (SIGSTOP - 1)));
+      if (how == SIG_BLOCK) {
+        ThreadData.GuestProcMask |= *set & IgnoredSignalsMask;
+      }
+      else if (how == SIG_UNBLOCK) {
+        ThreadData.GuestProcMask &= *set & IgnoredSignalsMask;
+      }
+      else if (how == SIG_SETMASK) {
+        ThreadData.GuestProcMask = *set & IgnoredSignalsMask;
+      }
+      else {
+        return -EINVAL;
+      }
+    }
+
+    return 0;
+  }
 }

External/FEXCore/Source/Interface/Core/SignalDelegator.h

@@ -82,6 +82,8 @@ namespace Core {
 
     uint64_t RegisterGuestSigAltStack(const stack_t *ss, stack_t *old_ss);
 
+    uint64_t GuestSigProcMask(int how, const uint64_t *set, uint64_t *oldset);
+
     // Called from the thunk handler to handle the signal
     void HandleSignal(int Signal, void *Info, void *UContext);
 

External/FEXCore/Source/Interface/HLE/Syscalls/Signals.cpp

@@ -14,10 +14,8 @@ namespace FEXCore::HLE {
       return Thread->CTX->SignalDelegation.RegisterGuestSignalHandler(signum, act, oldact);
     });
 
-    REGISTER_SYSCALL_IMPL(rt_sigprocmask, [](FEXCore::Core::InternalThreadState *Thread, int how, const sigset_t *set, sigset_t *oldset) -> uint64_t {
-      // XXX: Pass through SignalDelegator
-      uint64_t Result = ::sigprocmask(how, set, oldset);
-      SYSCALL_ERRNO();
+    REGISTER_SYSCALL_IMPL(rt_sigprocmask, [](FEXCore::Core::InternalThreadState *Thread, int how, const uint64_t *set, uint64_t *oldset) -> uint64_t {
+      return Thread->CTX->SignalDelegation.GuestSigProcMask(how, set, oldset);
     });
 
     REGISTER_SYSCALL_IMPL(sigaltstack, [](FEXCore::Core::InternalThreadState *Thread, const stack_t *ss, stack_t *old_ss) -> uint64_t {