[Lldb-commits] [lldb] [lldb] Updated lldb-server to spawn the child process and share socket (PR #101283)

[Pavel Labath via lldb-commits]

================
@@ -44,6 +47,112 @@ using namespace llvm;
 
 // option descriptors for getopt_long_only()
 
+#ifdef _WIN32
+typedef pipe_t fd_t;
+const fd_t kInvalidSharedFD = LLDB_INVALID_PIPE;
+#else
+typedef NativeSocket fd_t;
+const fd_t kInvalidSharedFD = Socket::kInvalidSocketValue;
+#endif
+
+class SharedSocket {
+public:
+  // Used by the parent process.
+  SharedSocket(Connection *conn, Status &error) {
+    m_fd = kInvalidSharedFD;
+
+    const Socket *socket =
+        static_cast<const Socket *>(conn->GetReadObject().get());
+    if (socket == nullptr) {
+      error = Status("invalid conn socket");
+      return;
+    }
+
+#ifdef _WIN32
+    m_socket = socket->GetNativeSocket();
+
+    // Create a pipe to transfer WSAPROTOCOL_INFO to the child process.
+    error = m_socket_pipe.CreateNew(true);
+    if (error.Fail())
+      return;
+
+    m_fd = m_socket_pipe.GetReadPipe();
+#else
+    m_fd = socket->GetNativeSocket();
+    error = Status();
+#endif
+  }
+
+  // Used by the child process.
+  SharedSocket(fd_t fd) : m_fd(fd) {}
+
+  fd_t GetSendableFD() { return m_fd; }
+
+  Status CompleteSending(lldb::pid_t child_pid) {
+#ifdef _WIN32
+    // Transfer WSAPROTOCOL_INFO to the child process.
+    m_socket_pipe.CloseReadFileDescriptor();
+
+    WSAPROTOCOL_INFO protocol_info;
+    if (::WSADuplicateSocket(m_socket, child_pid, &protocol_info) ==
+        SOCKET_ERROR) {
+      int last_error = ::WSAGetLastError();
+      return Status("WSADuplicateSocket() failed, error: %d", last_error);
+    }
+
+    size_t num_bytes;
+    Status error =
+        m_socket_pipe.WriteWithTimeout(&protocol_info, sizeof(protocol_info),
+                                       std::chrono::seconds(10), num_bytes);
+    if (error.Fail())
+      return error;
+    if (num_bytes != sizeof(protocol_info))
+      return Status("WriteWithTimeout(WSAPROTOCOL_INFO) failed: %d bytes",
+                    num_bytes);
+#endif
+    return Status();
+  }
+
+  Status GetNativeSocket(NativeSocket &socket) {
----------------
labath wrote:

I think this would be better off as a static function -- it's not using any of the members except m_fd, which could just as easily be a function argument, and it's duplicating the Pipe and NativeSocket members as local vars.

I can also imagine with a proper member function version of it, but then I think should reuse the members in the class. For example, by putting most of this work into the constructor, where it will initialize the m_pipe member and use it to receive the NativeSocket. `GetNativeSocket` could then be a plain getter (?)

https://github.com/llvm/llvm-project/pull/101283