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

ipc/unix_domain_socket_util.h

+// 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.
+
+#ifndef IPC_UNIX_DOMAIN_SOCKET_UTIL_H_
+#define IPC_UNIX_DOMAIN_SOCKET_UTIL_H_
+
+#include <string>
+#include <sys/types.h>
+
+namespace base {
+class FilePath;
+}  // namespace base
+
+namespace IPC {
+
+// Creates a UNIX-domain socket at |pipe_name| and bind()s it, then listen()s
+// on it. If successful, |server_listen_fd| will be set to the new file
+// descriptor, and the function will return true. Otherwise returns false.
+bool CreateServerUnixDomainSocket(const base::FilePath& pipe_name,
+                                  int* server_listen_fd);
+
+// Creates a UNIX-domain socket at |pipe_name| and connect()s to it. If

[palmer, 2013/03/05 00:12:31]

NIT: I'd say "opens" here instead of "creates".

[jeremya, 2013/03/05 03:27:19]

Done.

+// successful, |client_socket| will be set to the new file descriptor, and
+// the function will return true. Otherwise returns false.
+bool CreateClientUnixDomainSocket(const base::FilePath& pipe_name,
+                                  int* client_socket);
+
+// Gets the effective user ID of the other end of the UNIX-domain socket
+// specified by |fd|. If successful, sets |client_euid| to the uid, and returns
+// true. Otherwise returns false.
+bool GetPeerEuid(int fd, uid_t* client_euid);
+
+// Accepts a client attempting to connect to |server_listen_fd|, storing the
+// new file descriptor for the connection in |server_socket| and returning true
+// if successful.
+bool ServerAcceptConnection(int server_listen_fd, int* server_socket);
+
+// The maximum length of the name of a pipe for MODE_NAMED_SERVER or
+// MODE_NAMED_CLIENT if you want to pass in your own socket.
+// The standard size on linux is 108, mac is 104. To maintain consistency
+// across platforms we standardize on the smaller value.
+static const size_t kMaxPipeNameLength = 104;
+
+}  // namespace IPC
+
+#endif  // IPC_UNIX_DOMAIN_SOCKET_UTIL_H_