Merge pull request #362 from Sonicadvance1/fix_guest_signal_dfl

Fixes guest default signal handling and pending signals

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

@@ -7,6 +7,10 @@
 
 #include <string.h>
 
+#include <linux/futex.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
 namespace FEXCore {
   constexpr static uint32_t SS_AUTODISARM = (1U << 31);
   constexpr static uint32_t X86_MINSIGSTKSZ  = 0x2000U;
@@ -116,9 +120,25 @@ namespace FEXCore {
 
       // We have an emulation thread pointer, we can now modify its state
       if (Handler.GuestAction.sigaction_handler.handler == SIG_DFL) {
-        // XXX: Maybe this should actually go down guest handler state?
-        signal(Signal, SIG_DFL);
-        return;
+        if (Handler.DefaultBehaviour == DEFAULT_TERM) {
+          if (Thread->State.ThreadManager.clear_child_tid) {
+            std::atomic<uint32_t> *Addr = reinterpret_cast<std::atomic<uint32_t>*>(Thread->State.ThreadManager.clear_child_tid);
+            Addr->store(0);
+            syscall(SYS_futex,
+                Thread->State.ThreadManager.clear_child_tid,
+                FUTEX_WAKE,
+                ~0ULL,
+                0,
+                0,
+                0);
+          }
+
+          Thread->StatusCode = -Signal;
+
+          // Doesn't return
+          Thread->CTX->StopThread(Thread);
+          std::unexpected();
+        }
       }
       else if (Handler.GuestAction.sigaction_handler.handler == SIG_IGN) {
         return;
@@ -238,6 +258,29 @@ namespace FEXCore {
     // "Userspace" SIGRTMIN starts at 34 because of this
     HostHandlers[__SIGRTMIN].Installed   = true;
     HostHandlers[__SIGRTMIN+1].Installed = true;
+
+    // Most signals default to termination
+    // These ones are slightly different
+    const std::vector<std::pair<int, SignalDelegator::DefaultBehaviour>> SignalDefaultBehaviours = {
+      {SIGQUIT,   DEFAULT_COREDUMP},
+      {SIGILL,    DEFAULT_COREDUMP},
+      {SIGTRAP,   DEFAULT_COREDUMP},
+      {SIGABRT,   DEFAULT_COREDUMP},
+      {SIGBUS,    DEFAULT_COREDUMP},
+      {SIGFPE,    DEFAULT_COREDUMP},
+      {SIGSEGV,   DEFAULT_COREDUMP},
+      {SIGCHLD,   DEFAULT_IGNORE},
+      {SIGCONT,   DEFAULT_IGNORE},
+      {SIGURG,    DEFAULT_IGNORE},
+      {SIGXCPU,   DEFAULT_COREDUMP},
+      {SIGXFSZ,   DEFAULT_COREDUMP},
+      {SIGSYS,    DEFAULT_COREDUMP},
+      {SIGWINCH,  DEFAULT_IGNORE},
+    };
+
+    for (auto Behaviour : SignalDefaultBehaviours) {
+      HostHandlers[Behaviour.first].DefaultBehaviour = Behaviour.second;
+    }
   }
 
   void SignalDelegator::RegisterTLSState(FEXCore::Core::InternalThreadState *Thread) {
@@ -438,6 +481,17 @@ namespace FEXCore {
       }
     }
 
+    // Do we have any pending signals that became unmasked?
+    uint64_t PendingSignals = ~ThreadData.GuestProcMask & ThreadData.PendingSignals;
+    if (PendingSignals != 0) {
+      for (int i = 0; i < 64; ++i) {
+        if (PendingSignals & (1ULL << i)) {
+          tgkill(ThreadData.Thread->State.ThreadManager.PID, ThreadData.Thread->State.ThreadManager.TID, i + 1);
+          PendingSignals &= ~(1ULL << i);
+        }
+      }
+    }
+
     return 0;
   }
 

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

@@ -97,6 +97,14 @@ namespace Core {
     constexpr static size_t SIGNAL_FOR_PAUSE {63};
 
   private:
+    enum DefaultBehaviour {
+      DEFAULT_TERM,
+      // Core dump based signals are supposed to have a coredump appear
+      // For FEX's behaviour we don't really care right now
+      DEFAULT_COREDUMP = DEFAULT_TERM,
+      DEFAULT_IGNORE,
+    };
+
     struct SignalHandler {
       std::atomic<bool> Installed{};
       struct sigaction HostAction{};
@@ -104,6 +112,7 @@ namespace Core {
       HostSignalDelegatorFunction Handler{};
       HostSignalDelegatorFunctionForGuest GuestHandler{};
       GuestSigAction GuestAction{};
+      DefaultBehaviour DefaultBehaviour {DEFAULT_TERM};
     };
 
     SignalHandler HostHandlers[MAX_SIGNALS + 1]{};

unittests/POSIX/Disabled_Tests

@@ -1,5 +1,8 @@
 # These tests are inconsistent
 conformance-interfaces-mmap-12-1.test
+conformance-interfaces-mmap-6-1.test
+conformance-interfaces-mmap-6-2.test
+conformance-interfaces-mmap-6-3.test
 
 # These tests take too long to run, and might timeout
 conformance-interfaces-clock-1-1.test
@@ -545,3 +548,5 @@ conformance-interfaces-mmap-11-2.test
 conformance-interfaces-munmap-1-1.test
 conformance-interfaces-munmap-1-2.test
 
+conformance-interfaces-killpg-1-2.test # uses rt_sigsuspend
+conformance-interfaces-kill-1-2.test # uses rt_sigtimedwait

unittests/POSIX/Known_Failures

@@ -11,7 +11,6 @@ conformance-interfaces-munmap-2-1.test
 conformance-interfaces-nanosleep-10000-1.test
 conformance-interfaces-nanosleep-5-1.test
 conformance-interfaces-nanosleep-6-1.test
-conformance-interfaces-raise-1-1.test
 conformance-interfaces-sigpending-1-2.test
 conformance-interfaces-sigpending-1-3.test
 conformance-interfaces-sigprocmask-6-1.test
@@ -46,8 +45,6 @@ conformance-interfaces-sigwaitinfo-8-1.test
 conformance-interfaces-sigwaitinfo-9-1.test
 conformance-interfaces-clock_nanosleep-10-1.test # uses sigabort
 conformance-interfaces-clock_nanosleep-9-1.test # uses sigabort
-conformance-interfaces-kill-1-2.test # uses rt_sigtimedwait
-conformance-interfaces-killpg-1-2.test # uses getpgid, setpgid
 conformance-interfaces-nanosleep-5-2.test # uses sigabort
 conformance-interfaces-nanosleep-7-1.test # uses sigabort
 conformance-interfaces-nanosleep-7-2.test # uses sigabort