Implement IPC::ChannelFactory, a class that accept()s on a UNIX socket.

ipc/ipc_channel_factory.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ipc/ipc_channel_factory.h"
+
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "ipc/unix_domain_socket_util.h"
+
+namespace IPC {
+
+ChannelFactory::ChannelFactory(const base::FilePath& path, Delegate* delegate)
+    : path_(path), delegate_(delegate), listen_fd_(-1) {
+  DCHECK(delegate_);
+  CreateSocket();
+}
+
+ChannelFactory::~ChannelFactory() {
+  Close();
+}
+
+bool ChannelFactory::CreateSocket() {
+  DCHECK(listen_fd_ < 0);
+
+  // Create the socket.
+  return CreateServerUnixDomainSocket(path_, &listen_fd_);
+}
+
+bool ChannelFactory::Listen() {
+  if (listen_fd_ < 0)
+    return false;
+
+  // Watch the fd for connections, and turn any connections into
+  // active sockets.
+  MessageLoopForIO::current()->WatchFileDescriptor(
+      listen_fd_,
+      true,
+      MessageLoopForIO::WATCH_READ,
+      &server_listen_connection_watcher_,
+      this);
+  return true;
+}
+
+// Called by libevent when we can read from the fd without blocking.
+void ChannelFactory::OnFileCanReadWithoutBlocking(int fd) {
+  DCHECK(fd == listen_fd_);
+  int new_fd = -1;
+  if (!ServerAcceptConnection(listen_fd_, &new_fd)) {
+    Close();
+    delegate_->OnListenError();
+    return;
+  }
+
+  if (new_fd < 0) {
+    // The accept() failed, but not in such a way that the factory needs to be
+    // shut down.
+    return;
+  }
+
+  file_util::ScopedFD scoped_fd(&new_fd);
+
+  // Verify that the IPC channel peer is running as the same user.
+  if (!IsPeerAuthorized(new_fd))
+    return;
+
+  ChannelHandle handle("", base::FileDescriptor(*scoped_fd.release(), true));
+  delegate_->OnClientConnected(handle);
+}
+
+void ChannelFactory::OnFileCanWriteWithoutBlocking(int fd) {
+  NOTREACHED() << "Listen fd should never be writable.";
+}
+
+void ChannelFactory::Close() {
+  if (listen_fd_ < 0)
+    return;
+  if (HANDLE_EINTR(close(listen_fd_)) < 0)
+    PLOG(ERROR) << "close";
+  listen_fd_ = -1;
+  if (unlink(path_.value().c_str()) < 0)
+    PLOG(ERROR) << "unlink";
+
+  // Unregister libevent for the listening socket and close it.
+  server_listen_connection_watcher_.StopWatchingFileDescriptor();
+}
+
+}  // namespace IPC