Accept inbound connections on unix domain socket

mojo/shell/incoming_connection_listener.cc

Index: mojo/shell/incoming_connection_listener.cc
diff --git a/mojo/shell/incoming_connection_listener.cc b/mojo/shell/incoming_connection_listener.cc
new file mode 100644
index 0000000000000000000000000000000000000000..24dc3e58901f57eb3909b57b68813068fd8a3202
--- /dev/null
+++ b/mojo/shell/incoming_connection_listener.cc
@@ -0,0 +1,110 @@
+// Copyright 2014 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 "mojo/shell/incoming_connection_listener.h"
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/sequenced_task_runner.h"
+#include "base/tracked_objects.h"
+#include "net/base/net_errors.h"
+#include "net/socket/socket_descriptor.h"
+#include "net/socket/unix_domain_server_socket_posix.h"
+
+namespace mojo {
+namespace shell {
+
+namespace {
+// TODO(cmasone): Figure out what we should be doing about "authenticating" the
+// process trying to connect.
+bool Yes(const net::UnixDomainServerSocket::Credentials& ignored) {
+  return true;
+}
+}  // anonymous namespace
+
+IncomingConnectionListener::Delegate::Delegate() {
+}
+
+IncomingConnectionListener::Delegate::~Delegate() {
+}
+
+IncomingConnectionListener::IncomingConnectionListener(
+    const base::FilePath& socket_path,
+    Delegate* delegate)
+    : delegate_(delegate),
+      socket_path_(socket_path),
+      listen_socket_(base::Bind(&Yes), false),
+      incoming_socket_(net::kInvalidSocket),
+      weak_ptr_factory_(this) {
+  DCHECK(delegate_);
+}
+
+IncomingConnectionListener::~IncomingConnectionListener() {
+  weak_ptr_factory_.InvalidateWeakPtrs();
+  if (!base::DeleteFile(socket_path_, false))
+    PLOG(ERROR) << "Listening Unix domain socket can't be destroyed.";
+}
+
+void IncomingConnectionListener::StartListening() {
+  DCHECK(listen_thread_checker_.CalledOnValidThread());
+
+  int rv = net::OK;
+  if (base::PathExists(socket_path_)) {
+    LOG(ERROR) << "Listening socket file already exists.";
+    rv = net::ERR_FILE_EXISTS;
+  } else if (!base::DirectoryExists(socket_path_.DirName())) {
+    LOG(ERROR) << "Directorty for listening socket does not exist.";
+    rv = net::ERR_FILE_NOT_FOUND;
+  } else if (!base::PathIsWritable(socket_path_.DirName())) {
+    LOG(ERROR) << "Listening socket file path is not writable.";
+    rv = net::ERR_ACCESS_DENIED;
+  } else {
+    const std::string& socket_address = socket_path_.value();
+    rv = listen_socket_.ListenWithAddressAndPort(socket_address, 0, 100);
+  }
+
+  // Call OnListening() before Accept(), so that the delegate is certain to
+  // hear about listening before a connection might be accepted below.
+  delegate_->OnListening(rv);
+  if (rv == net::OK) {

[DaveMoore, 2014/09/26 22:48:57]

Nit: no braces

[Chris Masone, 2014/09/27 00:46:30]

Done.

+    Accept();
+  }
+}
+
+void IncomingConnectionListener::Accept() {
+  DCHECK(listen_thread_checker_.CalledOnValidThread());
+  int rv = listen_socket_.AcceptSocketDescriptor(
+      &incoming_socket_,
+      base::Bind(&IncomingConnectionListener::OnAccept,
+                 weak_ptr_factory_.GetWeakPtr()));
+
+  // If rv == net::ERR_IO_PENDING), listen_socket_ will call
+  // OnAccept() later, when a connection attempt comes in.
+  if (rv != net::ERR_IO_PENDING) {
+    DVLOG_IF(1, rv == net::OK) << "Accept succeeded immediately";
+    OnAccept(rv);
+  }
+}
+
+void IncomingConnectionListener::OnAccept(int rv) {
+  DCHECK(listen_thread_checker_.CalledOnValidThread());
+
+  if (rv != net::OK || incoming_socket_ == net::kInvalidSocket) {
+    LOG_IF(ERROR, rv != net::OK) << "Accept failed " << net::ErrorToString(rv);
+    PLOG_IF(ERROR, rv == net::OK) << "Socket invalid";
+  } else {
+    // Passes ownership of incoming_socket_ to delegate_.
+    delegate_->OnConnection(incoming_socket_);
+    incoming_socket_ = net::kInvalidSocket;
+  }
+
+  // Continue waiting to accept incoming connections...
+  Accept();
+}
+
+}  // namespace shell
+}  // namespace mojo