GCAdapter: improve thread safety

make sure Reset() can’t be run concurrently with AddGCAdapter() or
ResetRumble() (which is called on other threads) which can cause
crashes (issue #9462)
This commit is contained in:
mathieui 2016-04-30 13:29:11 +02:00
parent e629727572
commit 54b4efff6b
1 changed files with 22 additions and 3 deletions

View File

@ -22,6 +22,7 @@ namespace GCAdapter
{
static bool CheckDeviceAccess(libusb_device* device);
static void AddGCAdapter(libusb_device* device);
static void ResetRumbleLockNeeded();
static bool s_detected = false;
static libusb_device_handle* s_handle = nullptr;
@ -37,6 +38,7 @@ static std::atomic<int> s_controller_payload_size = {0};
static std::thread s_adapter_thread;
static Common::Flag s_adapter_thread_running;
static std::mutex s_init_mutex;
static std::thread s_adapter_detect_thread;
static Common::Flag s_adapter_detect_thread_running;
@ -77,7 +79,10 @@ static int HotplugCallback(libusb_context* ctx, libusb_device* dev, libusb_hotpl
if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED)
{
if (s_handle == nullptr && CheckDeviceAccess(dev))
{
std::lock_guard<std::mutex> lk(s_init_mutex);
AddGCAdapter(dev);
}
}
else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT)
{
@ -115,6 +120,7 @@ static void ScanThreadFunc()
{
if (s_handle == nullptr)
{
std::lock_guard<std::mutex> lk(s_init_mutex);
Setup();
if (s_detected && s_detect_callback != nullptr)
s_detect_callback();
@ -306,7 +312,7 @@ static void AddGCAdapter(libusb_device* device)
s_detected = true;
if (s_detect_callback != nullptr)
s_detect_callback();
ResetRumble();
ResetRumbleLockNeeded();
}
void Shutdown()
@ -329,6 +335,9 @@ void Shutdown()
void Reset()
{
std::unique_lock<std::mutex> lock(s_init_mutex, std::defer_lock);
if (!lock.try_lock())
return;
if (!s_detected)
return;
@ -439,10 +448,20 @@ bool UseAdapter()
void ResetRumble()
{
if (!UseAdapter())
std::unique_lock<std::mutex> lock(s_init_mutex, std::defer_lock);
if (!lock.try_lock())
return;
if (s_handle == nullptr || !s_detected)
ResetRumbleLockNeeded();
}
// Needs to be called when s_init_mutex is locked in order to avoid
// being called while the libusb state is being reset
static void ResetRumbleLockNeeded()
{
if (!UseAdapter() || (s_handle == nullptr || !s_detected))
{
return;
}
std::fill(std::begin(s_controller_rumble), std::end(s_controller_rumble), 0);