Expand possible socket dirs.

(Yoinked from <SlimeVR/SlimeVR-OpenVR-Driver#44>)

src/bridge.cpp

@@ -140,12 +140,28 @@ class UnixSocketBridge final : public SlimeVRBridge {
 
     void connect() final {
         if (!client.IsOpen()) {
+            fs::path socket;
             // TODO: do this once in the constructor or something
-            if (const char* ptr = std::getenv("XDG_RUNTIME_DIR")) {
+            if(const char* ptr = std::getenv("XDG_RUNTIME_DIR")) {
                 const fs::path xdg_runtime = ptr;
-                client.Open((xdg_runtime / SOCKET_NAME).native());
-            } else {
-                client.Open((fs::path(TMP_DIR) / SOCKET_NAME).native());
+                socket = (xdg_runtime / SOCKET_NAME);
+            }
+            if(!fs::exists(socket)) {
+                socket = (fs::path(TMP_DIR) / SOCKET_NAME);
+            }
+            // try using home dir if the vrserver is run in a chroot like
+            if(!fs::exists(socket)) {
+                if (const char* ptr = std::getenv("XDG_DATA_DIR")) {
+                    const fs::path data_dir = ptr;
+                    socket = (data_dir / SLIMEVR_DATA_DIR / SOCKET_NAME);
+                } else if (const char* ptr = std::getenv("HOME")) {
+                    const fs::path home = ptr;
+                    socket = (home / XDG_DATA_DIR_DEFAULT / SLIMEVR_DATA_DIR / SOCKET_NAME);
+                }
+            }
+            if(fs::exists(socket)) {
+                driver.Log("bridge socket: " + std::string(socket));
+                client.Open(socket.native());
             }
         }
     }