diff -r 000000000000 -r 6474c204b198 hal/gonk/UeventPoller.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hal/gonk/UeventPoller.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,226 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* Copyright 2012 Mozilla Foundation and Mozilla contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include <strings.h>
+#include <unistd.h>
+
+#include <arpa/inet.h>
+#include <linux/types.h>
+#include <linux/netlink.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+
+#include "nsDebug.h"
+#include "base/message_loop.h"
+#include "mozilla/FileUtils.h"
+#include "nsAutoPtr.h"
+#include "nsThreadUtils.h"
+#include "nsXULAppAPI.h"
+
+#include "UeventPoller.h"
+
+namespace mozilla {
+namespace hal_impl {
+
+static void ShutdownUevent();
+
+class NetlinkPoller : public MessageLoopForIO::Watcher
+{
+public:
+  NetlinkPoller() : mSocket(-1),
+                    mIOLoop(MessageLoopForIO::current())
+  {
+  }
+
+  virtual ~NetlinkPoller() {}
+
+  bool OpenSocket();
+
+  virtual void OnFileCanReadWithoutBlocking(int fd);
+
+  // no writing to the netlink socket
+  virtual void OnFileCanWriteWithoutBlocking(int fd)
+  {
+    MOZ_CRASH("Must not write to netlink socket");
+  }
+
+  MessageLoopForIO *GetIOLoop () const { return mIOLoop; }
+  void RegisterObserver(IUeventObserver *aObserver)
+  {
+    mUeventObserverList.AddObserver(aObserver);
+  }
+
+  void UnregisterObserver(IUeventObserver *aObserver)
+  {
+    mUeventObserverList.RemoveObserver(aObserver);
+    if (mUeventObserverList.Length() == 0)
+      ShutdownUevent();  // this will destroy self
+  }
+
+private:
+  ScopedClose mSocket;
+  MessageLoopForIO* mIOLoop;
+  MessageLoopForIO::FileDescriptorWatcher mReadWatcher;
+
+  const static int kBuffsize = 64 * 1024;
+  uint8_t mBuffer [kBuffsize];
+
+  typedef ObserverList<NetlinkEvent> UeventObserverList;
+  UeventObserverList mUeventObserverList;
+};
+
+bool
+NetlinkPoller::OpenSocket()
+{
+  mSocket.rwget() = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
+  if (mSocket.get() < 0)
+    return false;
+
+  int sz = kBuffsize;
+
+  if (setsockopt(mSocket.get(), SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz)) < 0)
+    return false;
+
+  // add FD_CLOEXEC flag
+  int flags = fcntl(mSocket.get(), F_GETFD);
+  if (flags == -1) {
+      return false;
+  }
+  flags |= FD_CLOEXEC;
+  if (fcntl(mSocket.get(), F_SETFD, flags) == -1)
+    return false;
+
+  // set non-blocking
+  if (fcntl(mSocket.get(), F_SETFL, O_NONBLOCK) == -1)
+    return false;
+
+  struct sockaddr_nl saddr;
+  bzero(&saddr, sizeof(saddr));
+  saddr.nl_family = AF_NETLINK;
+  saddr.nl_groups = 1;
+  saddr.nl_pid = gettid();
+
+  do {
+    if (bind(mSocket.get(), (struct sockaddr *)&saddr, sizeof(saddr)) == 0) {
+      break;
+    }
+
+    if (errno != EADDRINUSE) {
+      return false;
+    }
+
+    if (saddr.nl_pid == 0) {
+      return false;
+    }
+
+    // Once there was any other place in the same process assigning saddr.nl_pid by
+    // gettid(), we can detect it and print warning message.
+    printf_stderr("The netlink socket address saddr.nl_pid=%u is in use. Let the kernel re-assign.\n", saddr.nl_pid);
+    saddr.nl_pid = 0;
+  } while (true);
+
+  if (!mIOLoop->WatchFileDescriptor(mSocket.get(),
+                                    true,
+                                    MessageLoopForIO::WATCH_READ,
+                                    &mReadWatcher,
+                                    this)) {
+      return false;
+  }
+
+  return true;
+}
+
+static nsAutoPtr<NetlinkPoller> sPoller;
+
+class UeventInitTask : public Task
+{
+  virtual void Run()
+  {
+    if (!sPoller) {
+      return;
+    }
+    if (sPoller->OpenSocket()) {
+      return;
+    }
+    sPoller->GetIOLoop()->PostDelayedTask(FROM_HERE, new UeventInitTask(), 1000);
+  }
+};
+
+void
+NetlinkPoller::OnFileCanReadWithoutBlocking(int fd)
+{
+  MOZ_ASSERT(fd == mSocket.get());
+  while (true) {
+    int ret = read(fd, mBuffer, kBuffsize);
+    if (ret == -1) {
+      if (errno == EAGAIN || errno == EWOULDBLOCK) {
+        return;
+      }
+      if (errno == EINTR) {
+        continue;
+      }
+    }
+    if (ret <= 0) {
+      // fatal error on netlink socket which should not happen
+      _exit(1);
+    }
+    NetlinkEvent netlinkEvent;
+    netlinkEvent.decode(reinterpret_cast<char*>(mBuffer), ret);
+    mUeventObserverList.Broadcast(netlinkEvent);
+  }
+}
+
+static void
+InitializeUevent()
+{
+  MOZ_ASSERT(!sPoller);
+  sPoller = new NetlinkPoller();
+  sPoller->GetIOLoop()->PostTask(FROM_HERE, new UeventInitTask());
+
+}
+
+static void
+ShutdownUevent()
+{
+  sPoller = nullptr;
+}
+
+void
+RegisterUeventListener(IUeventObserver *aObserver)
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+
+  if (!sPoller)
+    InitializeUevent();
+  sPoller->RegisterObserver(aObserver);
+}
+
+void
+UnregisterUeventListener(IUeventObserver *aObserver)
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+
+  sPoller->UnregisterObserver(aObserver);
+}
+
+} // hal_impl
+} // mozilla
+