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author | Nikias Bassen | 2021-06-20 02:45:09 +0200 |
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committer | Nikias Bassen | 2021-06-20 02:45:09 +0200 |
commit | 5718dd2ae149f615191552eef40f8f90e60a3455 (patch) | |
tree | b6523e8d4a08b04445aa51eec864c255797e3a0c | |
parent | cb50087482cf5a4239ad9c96b7157c45eac12876 (diff) | |
download | libirecovery-5718dd2ae149f615191552eef40f8f90e60a3455.tar.gz libirecovery-5718dd2ae149f615191552eef40f8f90e60a3455.tar.bz2 |
Make sure the device event handler thread has started before returning from irecv_device_event_subscribe()
This fixes a potential deadlock that might occur when irecv_device_event_unsubscribe()
is called before the device event handler thread has started, eventually
resulting in a deadlock.
-rw-r--r-- | src/libirecovery.c | 40 |
1 files changed, 37 insertions, 3 deletions
diff --git a/src/libirecovery.c b/src/libirecovery.c index 84f0b32..39f6f88 100644 --- a/src/libirecovery.c +++ b/src/libirecovery.c @@ -2127,11 +2127,22 @@ static int _irecv_usb_hotplug_cb(libusb_context *ctx, libusb_device *device, lib #endif /* !HAVE_IOKIT */ #endif /* !WIN32 */ -static void *_irecv_event_handler(void* unused) +struct _irecv_event_handler_info { + cond_t startup_cond; + mutex_t startup_mutex; +}; + +static void *_irecv_event_handler(void* data) { + struct _irecv_event_handler_info* info = (struct _irecv_event_handler_info*)data; #ifdef WIN32 const GUID *guids[] = { &GUID_DEVINTERFACE_DFU, &GUID_DEVINTERFACE_IBOOT, NULL }; int running = 1; + + mutex_lock(&(info->startup_mutex)); + cond_signal(&(info->startup_cond)); + mutex_unlock(&(info->startup_mutex)); + do { SP_DEVICE_INTERFACE_DATA currentInterface; HDEVINFO usbDevices; @@ -2246,6 +2257,10 @@ static void *_irecv_event_handler(void* unused) i++; } + mutex_lock(&(info->startup_mutex)); + cond_signal(&(info->startup_cond)); + mutex_unlock(&(info->startup_mutex)); + CFRunLoopRun(); #else /* !HAVE_IOKIT */ @@ -2253,6 +2268,11 @@ static void *_irecv_event_handler(void* unused) static libusb_hotplug_callback_handle usb_hotplug_cb_handle; libusb_hotplug_register_callback(irecv_hotplug_ctx, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED | LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT, LIBUSB_HOTPLUG_ENUMERATE, APPLE_VENDOR_ID, LIBUSB_HOTPLUG_MATCH_ANY, 0, _irecv_usb_hotplug_cb, NULL, &usb_hotplug_cb_handle); int running = 1; + + mutex_lock(&(info->startup_mutex)); + cond_signal(&(info->startup_cond)); + mutex_unlock(&(info->startup_mutex)); + do { struct timeval tv; tv.tv_sec = tv.tv_usec = 0; @@ -2272,6 +2292,10 @@ static void *_irecv_event_handler(void* unused) libusb_device **devs; int running = 1; + mutex_lock(&(info->startup_mutex)); + cond_signal(&(info->startup_cond)); + mutex_unlock(&(info->startup_mutex)); + do { cnt = libusb_get_device_list(irecv_hotplug_ctx, &devs); if (cnt < 0) { @@ -2349,6 +2373,9 @@ IRECV_API irecv_error_t irecv_device_event_subscribe(irecv_device_event_context_ mutex_unlock(&listener_mutex); if (th_event_handler == THREAD_T_NULL || !thread_alive(th_event_handler)) { + struct _irecv_event_handler_info info; + cond_init(&info.startup_cond); + mutex_init(&info.startup_mutex); #ifndef WIN32 #ifndef HAVE_IOKIT libusb_init(&irecv_hotplug_ctx); @@ -2356,7 +2383,13 @@ IRECV_API irecv_error_t irecv_device_event_subscribe(irecv_device_event_context_ #endif collection_init(&devices); mutex_init(&device_mutex); - thread_new(&th_event_handler, _irecv_event_handler, NULL); + mutex_lock(&info.startup_mutex); + if (thread_new(&th_event_handler, _irecv_event_handler, &info) == 0) { + cond_wait(&info.startup_cond, &info.startup_mutex); + } + mutex_unlock(&info.startup_mutex); + cond_destroy(&info.startup_cond); + mutex_destroy(&info.startup_mutex); } *context = _context; @@ -2378,10 +2411,11 @@ IRECV_API irecv_error_t irecv_device_event_unsubscribe(irecv_device_event_contex int num = collection_count(&listeners); mutex_unlock(&listener_mutex); - if (num == 0) { + if (num == 0 && th_event_handler != THREAD_T_NULL && thread_alive(th_event_handler)) { #ifdef HAVE_IOKIT if (iokit_runloop) { CFRunLoopStop(iokit_runloop); + iokit_runloop = NULL; } #endif thread_join(th_event_handler); |