Merge pull request #3507 from Sonicadvance1/fd_tracking_check

FEXLoader: Add some debug-only tracking for FEX owned FDs
FEX-Emu · Mar 27, 2024 · 79454ed · 79454ed
2 parents 7f90ca5 + 60755ac
commit 79454ed
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Showing 3 changed files with 75 additions and 2 deletions.
diff --git a/Source/Tools/FEXLoader/FEXLoader.cpp b/Source/Tools/FEXLoader/FEXLoader.cpp
@@ -62,7 +62,7 @@ desc: Glues the ELF loader, FEXCore and LinuxSyscalls to launch an elf under fex
 
 namespace {
 static bool SilentLog;
-static int OutputFD {STDERR_FILENO};
+static int OutputFD {-1};
 static bool ExecutedWithFD {false};
 
 void MsgHandler(LogMan::DebugLevels Level, char const *Message) {
@@ -88,7 +88,7 @@ void AssertHandler(char const *Message) {
 } // Anonymous namespace
 
 namespace FEXServerLogging {
-  int FEXServerFD{};
+  int FEXServerFD{-1};
   void MsgHandler(LogMan::DebugLevels Level, char const *Message) {
     FEXServerClient::MsgHandler(FEXServerFD, Level, Message);
   }
@@ -456,6 +456,15 @@ int main(int argc, char **argv, char **const envp) {
   auto SyscallHandler = Loader.Is64BitMode() ? FEX::HLE::x64::CreateHandler(CTX.get(), SignalDelegation.get())
                                              : FEX::HLE::x32::CreateHandler(CTX.get(), SignalDelegation.get(), std::move(Allocator));
 
+  // Now that we have the syscall handler. Track some FDs that are FEX owned.
+  if (OutputFD != -1) {
+    SyscallHandler->FM.TrackFEXFD(OutputFD);
+  }
+  SyscallHandler->FM.TrackFEXFD(FEXServerClient::GetServerFD());
+  if (FEXServerLogging::FEXServerFD != -1) {
+    SyscallHandler->FM.TrackFEXFD(FEXServerLogging::FEXServerFD);
+  }
+
   {
     // Load VDSO in to memory prior to mapping our ELFs.
     void* VDSOBase = FEX::VDSO::LoadVDSOThunks(Loader.Is64BitMode(), SyscallHandler.get());

diff --git a/Source/Tools/LinuxEmulation/LinuxSyscalls/FileManagement.cpp b/Source/Tools/LinuxEmulation/LinuxSyscalls/FileManagement.cpp
@@ -250,6 +250,9 @@ FileManager::FileManager(FEXCore::Context::Context *ctx)
     if (RootFSFD == -1) {
       RootFSFD = AT_FDCWD;
     }
+    else {
+      TrackFEXFD(RootFSFD);
+    }
   }
 
   fextl::unordered_map<fextl::string, ThunkDBObject> ThunkDB;
@@ -571,13 +574,28 @@ uint64_t FileManager::Open(const char *pathname, int flags, uint32_t mode) {
 }
 
 uint64_t FileManager::Close(int fd) {
+#if defined(ASSERTIONS_ENABLED) && ASSERTIONS_ENABLED
+  if (CheckIfFDInTrackedSet(fd)) {
+    LogMan::Msg::EFmt("{} closing FEX FD {}", __func__, fd);
+    RemoveFEXFD(fd);
+  }
+#endif
+
   return ::close(fd);
 }
 
 uint64_t FileManager::CloseRange(unsigned int first, unsigned int last, unsigned int flags) {
 #ifndef CLOSE_RANGE_CLOEXEC
 #define CLOSE_RANGE_CLOEXEC (1U << 2)
 #endif
+#if defined(ASSERTIONS_ENABLED) && ASSERTIONS_ENABLED
+  if (!(flags & CLOSE_RANGE_CLOEXEC) &&
+      CheckIfFDRangeInTrackedSet(first, last)) {
+    LogMan::Msg::EFmt("{} closing FEX FDs in range ({}, {})", __func__, first, last);
+    RemoveFEXFDRange(first, last);
+  }
+#endif
+
   return ::syscall(SYSCALL_DEF(close_range), first, last, flags);
 }
 

diff --git a/Source/Tools/LinuxEmulation/LinuxSyscalls/FileManagement.h b/Source/Tools/LinuxEmulation/LinuxSyscalls/FileManagement.h
@@ -88,7 +88,53 @@ class FileManager final {
 
   bool SupportsProcFSInterpreterPath() const { return SupportsProcFSInterpreter; }
 
+#if defined(ASSERTIONS_ENABLED) && ASSERTIONS_ENABLED
+  void TrackFEXFD(int FD) noexcept {
+    std::lock_guard lk(FEXTrackingFDMutex);
+    FEXTrackingFDs.emplace(FD);
+  }
+
+  void RemoveFEXFD(int FD) noexcept {
+    std::lock_guard lk(FEXTrackingFDMutex);
+    FEXTrackingFDs.erase(FD);
+  }
+
+  void RemoveFEXFDRange(int begin, int end) noexcept {
+    std::lock_guard lk(FEXTrackingFDMutex);
+
+    std::erase_if(FEXTrackingFDs, [begin, end](int FD) {
+      return FD >= begin && (FD <= end || end == -1);
+    });
+  }
+
+  bool CheckIfFDInTrackedSet(int FD) noexcept {
+    std::lock_guard lk(FEXTrackingFDMutex);
+    return FEXTrackingFDs.contains(FD);
+  }
+
+  bool CheckIfFDRangeInTrackedSet(int begin, int end) noexcept {
+    std::lock_guard lk(FEXTrackingFDMutex);
+    // Just linear scan since the number of tracking FDs is low.
+    for (auto it : FEXTrackingFDs) {
+      if (it >= begin && (it <= end || end == -1)) return true;
+    }
+    return false;
+  }
+
+#else
+  void TrackFEXFD(int FD) const noexcept {}
+  bool CheckIfFDInTrackedSet(int FD) const noexcept { return false; }
+  void RemoveFEXFD(int FD) const noexcept {}
+  void RemoveFEXFDRange(int begin, int end) const noexcept {}
+  bool CheckIfFDRangeInTrackedSet(int begin, int end) const noexcept { return false; }
+#endif
+
 private:
+#if defined(ASSERTIONS_ENABLED) && ASSERTIONS_ENABLED
+  std::mutex FEXTrackingFDMutex;
+  fextl::set<int> FEXTrackingFDs;
+#endif
+
   bool RootFSPathExists(const char* Filepath);
 
   struct ThunkDBObject {