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 <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "ipc/ipc_channel_posix.h"
+#include "ipc/unix_domain_socket_util.h"
+
+namespace IPC {
+
+ChannelFactory::ChannelFactory(const base::FilePath& path, Delegate* delegate)
+    : path_(path), delegate_(delegate), listen_pipe_(-1), must_unlink_(false) {
+  DCHECK(delegate_);
+  CreatePipe();
+}
+
+ChannelFactory::~ChannelFactory() {
+  Close();
+}
+
+bool ChannelFactory::CreatePipe() {
+  DCHECK(listen_pipe_ < 0);
+
+  // Create the socket.
+  if (!CreateServerUnixDomainSocket(path_, &listen_pipe_))

[palmer, 2013/02/28 23:48:28]

Maybe just

    return CreateServerUnixDomainSocket(path_, &listen_pipe_);

?

[jeremya, 2013/03/01 03:49:25]

lol, good catch.

+    return false;
+  return true;
+}
+
+bool ChannelFactory::Listen() {
+  if (listen_pipe_ < 0)
+    return false;
+  // Watch the pipe for connections, and turn any connections into
+  // active sockets.
+  MessageLoopForIO::current()->WatchFileDescriptor(
+      listen_pipe_,
+      true,
+      MessageLoopForIO::WATCH_READ,
+      &server_listen_connection_watcher_,
+      this);
+  return true;
+}
+
+// Called by libevent when we can read from the pipe without blocking.
+void ChannelFactory::OnFileCanReadWithoutBlocking(int fd) {
+  DCHECK(fd == listen_pipe_);
+  int new_pipe = -1;
+  if (!ServerAcceptConnection(listen_pipe_, &new_pipe)) {
+    Close();
+    delegate_->OnListenError();
+    return;
+  }
+
+  // Verify that the IPC channel peer is running as the same user.
+  uid_t client_euid;
+  if (!GetPeerEuid(new_pipe, &client_euid)) {
+    close(new_pipe);
+    return;
+  }
+  if (client_euid != geteuid()) {

[palmer, 2013/02/28 23:48:28]

Both clients and servers will use this check on each other, right?

[jeremya, 2013/03/01 03:49:25]

Currently only the server checks.

[palmer, 2013/03/01 19:14:30]

Ahh. We'll need for both to check.

[jeremya, 2013/03/03 21:39:03]

Done.

+    DLOG(ERROR) << "Client euid is not authorised";
+    close(new_pipe);
+    return;
+  }
+
+  ChannelHandle handle("", base::FileDescriptor(new_pipe, true));
+  delegate_->OnClientConnected(handle);
+}
+
+void ChannelFactory::Close() {
+  if (listen_pipe_ >= 0) {

[palmer, 2013/02/28 23:48:28]

I'd sav a level of indentation by doing

  if (listen_pipe_ < 0)
    return;

[jeremya, 2013/03/01 03:49:25]

Done.

[jeremya, 2013/03/01 03:49:25]

Done.

+    HANDLE_EINTR(unlink(path_.value().c_str()));

[palmer, 2013/02/28 23:48:28]

Neither the Linux nor the OS X man pages for unlink(2) state that unlink can
incur EINTR.

I don't think using HANDLE_EINTR is hurting anything, though.

[jeremya, 2013/03/01 03:49:25]

Cool, I was confused when I should use it and when not. Removed.

+    if (HANDLE_EINTR(close(listen_pipe_)) < 0)
+      PLOG(ERROR) << "close";
+    listen_pipe_ = -1;
+    // Unregister libevent for the listening socket and close it.
+    server_listen_connection_watcher_.StopWatchingFileDescriptor();
+  }
+}
+
+}  // namespace IPC