[Tracing] Add a CanTrackErrors method to posix EE interface to allow RPC tracing with supportive endpoints (#32994)

src/core/lib/event_engine/posix.h

@@ -37,6 +37,10 @@ class PosixEndpointWithFdSupport : public EventEngine::Endpoint {
   /// Returns the file descriptor associated with the posix endpoint.
   virtual int GetWrappedFd() = 0;
 
+  /// Returns if the Endpoint supports tracking events from errmsg queues on
+  /// posix systems.
+  virtual bool CanTrackErrors() = 0;
+
   /// Shutdown the endpoint. This function call should trigger execution of
   /// any pending endpoint Read/Write callbacks with appropriate error
   /// absl::Status. After this function call any subsequent endpoint

src/core/lib/event_engine/posix_engine/posix_endpoint.h

@@ -493,6 +493,8 @@ class PosixEndpointImpl : public grpc_core::RefCounted<PosixEndpointImpl> {
 
   int GetWrappedFd() { return fd_; }
 
+  bool CanTrackErrors() const { return poller_->CanTrackErrors(); }
+
   void MaybeShutdown(
       absl::Status why,
       absl::AnyInvocable<void(absl::StatusOr<int> release_fd)> on_release_fd);
@@ -635,6 +637,8 @@ class PosixEndpoint : public PosixEndpointWithFdSupport {
 
   int GetWrappedFd() override { return impl_->GetWrappedFd(); }
 
+  bool CanTrackErrors() override { return impl_->CanTrackErrors(); }
+
   void Shutdown(absl::AnyInvocable<void(absl::StatusOr<int> release_fd)>
                     on_release_fd) override {
     if (!shutdown_.exchange(true, std::memory_order_acq_rel)) {
@@ -691,6 +695,11 @@ class PosixEndpoint : public PosixEndpointWithFdSupport {
         "PosixEndpoint::GetWrappedFd not supported on this platform");
   }
 
+  bool CanTrackErrors() override {
+    grpc_core::Crash(
+        "PosixEndpoint::CanTrackErrors not supported on this platform");
+  }
+
   void Shutdown(absl::AnyInvocable<void(absl::StatusOr<int> release_fd)>
                     on_release_fd) override {
     grpc_core::Crash("PosixEndpoint::Shutdown not supported on this platform");

src/core/lib/iomgr/event_engine_shims/endpoint.cc

@@ -256,6 +256,15 @@ class EventEngineEndpointWrapper {
     }
   }
 
+  bool CanTrackErrors() {
+    if (EventEngineSupportsFd()) {
+      return reinterpret_cast<PosixEndpointWithFdSupport*>(endpoint_.get())
+          ->CanTrackErrors();
+    } else {
+      return false;
+    }
+  }
+
  private:
   void OnShutdownInternal() {
     {
@@ -378,7 +387,12 @@ int EndpointGetFd(grpc_endpoint* ep) {
   return eeep->wrapper->Fd();
 }
 
-bool EndpointCanTrackErr(grpc_endpoint* /* ep */) { return false; }
+bool EndpointCanTrackErr(grpc_endpoint* ep) {
+  auto* eeep =
+      reinterpret_cast<EventEngineEndpointWrapper::grpc_event_engine_endpoint*>(
+          ep);
+  return eeep->wrapper->CanTrackErrors();
+}
 
 grpc_endpoint_vtable grpc_event_engine_endpoint_vtable = {
     EndpointRead,