Port the WindowServer and LibGUI to communicate through local sockets.

This is really cool! :^)

Apps currently refuse to start if the WindowServer isn't listening on the
socket in /wsportal. This makes sense, but I guess it would also be nice
to have some sort of "wait for server on startup" mode.

This has performance issues, and I'll work on those, but this stuff seems
to actually work and I'm very happy with that.

Kernel/Process.cpp

@@ -1784,6 +1784,13 @@ int Process::sys$ioctl(int fd, unsigned request, unsigned arg)
     auto* descriptor = file_descriptor(fd);
     if (!descriptor)
         return -EBADF;
+    if (descriptor->is_socket() && request == 413) {
+        auto* pid = (pid_t*)arg;
+        if (!validate_write_typed(pid))
+            return -EFAULT;
+        *pid = descriptor->socket()->origin_pid();
+        return 0;
+    }
     if (!descriptor->is_character_device())
         return -ENOTTY;
     return descriptor->character_device()->ioctl(*this, request, arg);
@@ -2347,10 +2354,23 @@ int Process::sys$connect(int sockfd, const sockaddr* address, socklen_t address_
         return -ENOTSOCK;
     auto& socket = *descriptor->socket();
     int error;
-    auto server = socket.connect(address, address_size, error);
-    if (!server)
+    if (!socket.connect(address, address_size, error))
         return error;
-    auto server_descriptor = FileDescriptor::create(move(server), SocketRole::Connected);
-    m_fds[fd].set(move(server_descriptor));
-    return fd;
+    descriptor->set_socket_role(SocketRole::Connected);
+    return 0;
+}
+
+bool Process::wait_for_connect(Socket& socket, int& error)
+{
+    if (socket.is_connected())
+        return true;
+    m_blocked_connecting_socket = socket;
+    block(BlockedConnect);
+    Scheduler::yield();
+    m_blocked_connecting_socket = nullptr;
+    if (!socket.is_connected()) {
+        error = -ECONNREFUSED;
+        return false;
+    }
+    return true;
 }