gecko-dev/ipc/dbus/DBusThread.cpp

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/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/*
* Copyright 2009, The Android Open Source Project
*
* 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.
*
* NOTE: Due to being based on the dbus compatibility layer for
* android's bluetooth implementation, this file is licensed under the
* apache license instead of MPL.
*
*/
#include "DBusThread.h"
#include "RawDBusConnection.h"
#include "DBusUtils.h"
#include <dbus/dbus.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/select.h>
#include <sys/types.h>
#include <string.h>
#include <stdint.h>
#include <stdio.h>
#include <string>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <poll.h>
#include <list>
#include "base/eintr_wrapper.h"
#include "base/message_loop.h"
#include "nsTArray.h"
#include "nsDataHashtable.h"
#include "mozilla/Monitor.h"
#include "mozilla/Util.h"
#include "mozilla/FileUtils.h"
#include "nsThreadUtils.h"
#include "nsIThread.h"
#include "nsXULAppAPI.h"
#include "nsServiceManagerUtils.h"
#include "nsCOMPtr.h"
#undef LOG
#if defined(MOZ_WIDGET_GONK)
#include <android/log.h>
#define LOG(args...) __android_log_print(ANDROID_LOG_INFO, "GonkDBus", args);
#else
#define BTDEBUG true
#define LOG(args...) if (BTDEBUG) printf(args);
#endif
#define DEFAULT_INITIAL_POLLFD_COUNT 8
// Functions for converting between unix events in the poll struct,
// and their dbus definitions
// TODO Add Wakeup to this list once we've moved to ics
enum {
DBUS_EVENT_LOOP_EXIT = 1,
DBUS_EVENT_LOOP_ADD = 2,
DBUS_EVENT_LOOP_REMOVE = 3,
DBUS_EVENT_LOOP_WAKEUP = 4,
} DBusEventTypes;
static unsigned int UnixEventsToDBusFlags(short events)
{
return (events & DBUS_WATCH_READABLE ? POLLIN : 0) |
(events & DBUS_WATCH_WRITABLE ? POLLOUT : 0) |
(events & DBUS_WATCH_ERROR ? POLLERR : 0) |
(events & DBUS_WATCH_HANGUP ? POLLHUP : 0);
}
static short DBusFlagsToUnixEvents(unsigned int flags)
{
return (flags & POLLIN ? DBUS_WATCH_READABLE : 0) |
(flags & POLLOUT ? DBUS_WATCH_WRITABLE : 0) |
(flags & POLLERR ? DBUS_WATCH_ERROR : 0) |
(flags & POLLHUP ? DBUS_WATCH_HANGUP : 0);
}
namespace mozilla {
namespace ipc {
struct PollFdComparator {
bool Equals(const pollfd& a, const pollfd& b) const {
return ((a.fd == b.fd) &&
(a.events == b.events));
}
bool LessThan(const pollfd& a, const pollfd&b) const {
return false;
}
};
// DBus Thread Class prototype
struct DBusThread : public RawDBusConnection
{
DBusThread();
~DBusThread();
bool StartEventLoop();
bool StopEventLoop();
bool IsEventLoopRunning();
void EventLoop();
// Thread members
nsCOMPtr<nsIThread> mThread;
// Information about the sockets we're polling. Socket counts
// increase/decrease depending on how many add/remove watch signals
// we're received via the control sockets.
nsTArray<pollfd> mPollData;
nsTArray<DBusWatch*> mWatchData;
// Sockets for receiving dbus control information (watch
// add/removes, loop shutdown, etc...)
ScopedClose mControlFdR;
ScopedClose mControlFdW;
protected:
bool SetUpEventLoop();
bool TearDownData();
};
static nsAutoPtr<DBusThread> sDBusThread;
// DBus utility functions
// Free statics, as they're used as function pointers in dbus setup
static dbus_bool_t
AddWatch(DBusWatch *aWatch, void *aData)
{
DBusThread *dbt = (DBusThread *)aData;
if (dbus_watch_get_enabled(aWatch)) {
// note that we can't just send the watch and inspect it later
// because we may get a removeWatch call before this data is reacted
// to by our eventloop and remove this watch.. reading the add first
// and then inspecting the recently deceased watch would be bad.
char control = DBUS_EVENT_LOOP_ADD;
if (write(dbt->mControlFdW.get(), &control, sizeof(char)) < 0) {
LOG("Cannot write DBus add watch control data to socket!\n");
return false;
}
int fd = dbus_watch_get_unix_fd(aWatch);
if (write(dbt->mControlFdW.get(), &fd, sizeof(int)) < 0) {
LOG("Cannot write DBus add watch descriptor data to socket!\n");
return false;
}
unsigned int flags = dbus_watch_get_flags(aWatch);
if (write(dbt->mControlFdW.get(), &flags, sizeof(unsigned int)) < 0) {
LOG("Cannot write DBus add watch flag data to socket!\n");
return false;
}
if (write(dbt->mControlFdW.get(), &aWatch, sizeof(DBusWatch*)) < 0) {
LOG("Cannot write DBus add watch struct data to socket!\n");
return false;
}
}
return true;
}
static void
RemoveWatch(DBusWatch *aWatch, void *aData)
{
DBusThread *dbt = (DBusThread *)aData;
char control = DBUS_EVENT_LOOP_REMOVE;
if (write(dbt->mControlFdW.get(), &control, sizeof(char)) < 0) {
LOG("Cannot write DBus remove watch control data to socket!\n");
return;
}
int fd = dbus_watch_get_unix_fd(aWatch);
if (write(dbt->mControlFdW.get(), &fd, sizeof(int)) < 0) {
LOG("Cannot write DBus remove watch descriptor data to socket!\n");
return;
}
unsigned int flags = dbus_watch_get_flags(aWatch);
if (write(dbt->mControlFdW.get(), &flags, sizeof(unsigned int)) < 0) {
LOG("Cannot write DBus remove watch flag data to socket!\n");
return;
}
}
static void
ToggleWatch(DBusWatch *aWatch, void *aData)
{
if (dbus_watch_get_enabled(aWatch)) {
AddWatch(aWatch, aData);
} else {
RemoveWatch(aWatch, aData);
}
}
static void
HandleWatchAdd(DBusThread* aDbt)
{
DBusWatch *watch;
int newFD;
unsigned int flags;
if (read(aDbt->mControlFdR.get(), &newFD, sizeof(int)) < 0) {
LOG("Cannot read DBus watch add descriptor data from socket!\n");
return;
}
if (read(aDbt->mControlFdR.get(), &flags, sizeof(unsigned int)) < 0) {
LOG("Cannot read DBus watch add flag data from socket!\n");
return;
}
if (read(aDbt->mControlFdR.get(), &watch, sizeof(DBusWatch *)) < 0) {
LOG("Cannot read DBus watch add watch data from socket!\n");
return;
}
short events = DBusFlagsToUnixEvents(flags);
pollfd p;
p.fd = newFD;
p.revents = 0;
p.events = events;
if (aDbt->mPollData.Contains(p, PollFdComparator())) return;
aDbt->mPollData.AppendElement(p);
aDbt->mWatchData.AppendElement(watch);
}
static void
HandleWatchRemove(DBusThread* aDbt)
{
int removeFD;
unsigned int flags;
if (read(aDbt->mControlFdR.get(), &removeFD, sizeof(int)) < 0) {
LOG("Cannot read DBus watch remove descriptor data from socket!\n");
return;
}
if (read(aDbt->mControlFdR.get(), &flags, sizeof(unsigned int)) < 0) {
LOG("Cannot read DBus watch remove flag data from socket!\n");
return;
}
short events = DBusFlagsToUnixEvents(flags);
pollfd p;
p.fd = removeFD;
p.events = events;
int index = aDbt->mPollData.IndexOf(p, 0, PollFdComparator());
// There are times where removes can be requested for watches that
// haven't been added (for example, whenever gecko comes up after
// adapters have already been enabled), so check to make sure we're
// using the watch in the first place
if (index < 0) {
LOG("DBus requested watch removal of non-existant socket, ignoring...");
return;
}
aDbt->mPollData.RemoveElementAt(index);
// DBusWatch pointers are maintained by DBus, so we won't leak by
// removing.
aDbt->mWatchData.RemoveElementAt(index);
}
static
void DBusWakeup(void* aData)
{
DBusThread *dbt = (DBusThread *)aData;
char control = DBUS_EVENT_LOOP_WAKEUP;
if (write(dbt->mControlFdW.get(), &control, sizeof(char)) < 0) {
NS_WARNING("Cannot write wakeup bit to DBus controller!");
}
}
// DBus Thread Implementation
DBusThread::DBusThread()
{
}
DBusThread::~DBusThread()
{
}
bool
DBusThread::SetUpEventLoop()
{
// If we already have a connection, exit
if (mConnection) {
return false;
}
dbus_threads_init_default();
DBusError err;
dbus_error_init(&err);
// If we can't establish a connection to dbus, nothing else will work
nsresult rv = EstablishDBusConnection();
if (NS_FAILED(rv)) {
NS_WARNING("Cannot create DBus Connection for DBus Thread!");
return false;
}
return true;
}
bool
DBusThread::TearDownData()
{
#ifdef DEBUG
LOG("Removing DBus Sockets\n");
#endif
if (mControlFdW.get()) {
mControlFdW.dispose();
}
if (mControlFdR.get()) {
mControlFdR.dispose();
}
mPollData.Clear();
// DBusWatch pointers are maintained by DBus, so we won't leak by
// clearing.
mWatchData.Clear();
return true;
}
void
DBusThread::EventLoop()
{
dbus_connection_set_watch_functions(mConnection, AddWatch,
RemoveWatch, ToggleWatch, this, NULL);
dbus_connection_set_wakeup_main_function(mConnection, DBusWakeup, this, NULL);
#ifdef DEBUG
LOG("DBus Event Loop Starting\n");
#endif
while (1) {
poll(mPollData.Elements(), mPollData.Length(), -1);
for (uint32_t i = 0; i < mPollData.Length(); i++) {
if (!mPollData[i].revents) {
continue;
}
if (mPollData[i].fd == mControlFdR.get()) {
char data;
while (recv(mControlFdR.get(), &data, sizeof(char), MSG_DONTWAIT)
!= -1) {
switch (data) {
case DBUS_EVENT_LOOP_EXIT:
#ifdef DEBUG
LOG("DBus Event Loop Exiting\n");
#endif
dbus_connection_set_watch_functions(mConnection,
NULL, NULL, NULL, NULL, NULL);
return;
case DBUS_EVENT_LOOP_ADD:
HandleWatchAdd(this);
break;
case DBUS_EVENT_LOOP_REMOVE:
HandleWatchRemove(this);
break;
case DBUS_EVENT_LOOP_WAKEUP:
// noop
break;
}
}
} else {
short events = mPollData[i].revents;
unsigned int flags = UnixEventsToDBusFlags(events);
dbus_watch_handle(mWatchData[i], flags);
mPollData[i].revents = 0;
// Break at this point since we don't know if the operation
// was destructive
break;
}
}
while (dbus_connection_dispatch(mConnection) ==
DBUS_DISPATCH_DATA_REMAINS)
{}
}
}
bool
DBusThread::StartEventLoop()
{
// socketpair opens two sockets for the process to communicate on.
// This is how android's implementation of the dbus event loop
// communicates with itself in relation to IPC signals. These
// sockets are contained sequentially in the same struct in the
// android code, but we break them out into class members here.
// Therefore we read into a local array and then copy.
int sockets[2];
if (socketpair(AF_LOCAL, SOCK_STREAM, 0, (int*)(&sockets)) < 0) {
TearDownData();
return false;
}
mControlFdR.rwget() = sockets[0];
mControlFdW.rwget() = sockets[1];
pollfd p;
p.fd = mControlFdR.get();
p.events = POLLIN;
mPollData.AppendElement(p);
// Due to the fact that mPollData and mWatchData have to match, we
// push a null to the front of mWatchData since it has the control
// fd in the first slot of mPollData.
mWatchData.AppendElement((DBusWatch*)NULL);
if (!SetUpEventLoop()) {
TearDownData();
return false;
}
if (NS_FAILED(NS_NewNamedThread("DBus Poll",
getter_AddRefs(mThread),
NS_NewNonOwningRunnableMethod(this,
&DBusThread::EventLoop)))) {
NS_WARNING("Cannot create DBus Thread!");
return false;
}
#ifdef DEBUG
LOG("DBus Thread Starting\n");
#endif
return true;
}
bool
DBusThread::StopEventLoop()
{
if (!mThread) {
return true;
}
char data = DBUS_EVENT_LOOP_EXIT;
ssize_t wret = write(mControlFdW.get(), &data, sizeof(char));
if(wret < 0) {
NS_ERROR("Cannot write exit flag to Dbus Thread!");
return false;
}
#ifdef DEBUG
LOG("DBus Thread Joining\n");
#endif
nsCOMPtr<nsIThread> tmpThread;
mThread.swap(tmpThread);
if(NS_FAILED(tmpThread->Shutdown())) {
NS_WARNING("DBus thread shutdown failed!");
}
#ifdef DEBUG
LOG("DBus Thread Joined\n");
#endif
TearDownData();
return true;
}
// Startup/Shutdown utility functions
bool
StartDBus()
{
MOZ_ASSERT(!NS_IsMainThread());
if (sDBusThread) {
NS_WARNING("Trying to start DBus Thread that is already currently running, skipping.");
return true;
}
nsAutoPtr<DBusThread> thread(new DBusThread());
if (!thread->StartEventLoop()) {
NS_WARNING("Cannot start DBus event loop!");
return false;
}
sDBusThread = thread;
return true;
}
bool
StopDBus()
{
MOZ_ASSERT(!NS_IsMainThread());
if (!sDBusThread) {
return true;
}
nsAutoPtr<DBusThread> thread(sDBusThread);
sDBusThread = nullptr;
return thread->StopEventLoop();
}
}
}