darwin: fix resource leak (cached devices are never freed)

For each new device (processed by hotplug code) darwin_ref_cached_device
is called twice - in process_new_device and in darwin_get_cached_device
(which is called from the first function). But when the device is detached
only one darwin_deref_cached_device is done - in darwin_destroy_device.
So there is inbalance between ref and deref which causes darwin_cached_devices
list to monotonically grow and consume more and more resources over time.
This commit fixes the problem by adding darwin_deref_cached_device call
to darwin_devices_detached.

Closes #52

Signed-off-by: Nathan Hjelm <hjelmn@mac.com>

diff --git a/libusb/os/darwin_usb.c b/libusb/os/darwin_usb.c
index e181ba8..9075de1 100644 (file)
--- a/libusb/os/darwin_usb.c
+++ b/libusb/os/darwin_usb.c
@@ -279,6 +279,7 @@ static void darwin_devices_attached (void *ptr, io_iterator_t add_devices) {
 static void darwin_devices_detached (void *ptr, io_iterator_t rem_devices) {
   struct libusb_device *dev = NULL;
   struct libusb_context *ctx;
+  struct darwin_cached_device *old_device;
 
   io_service_t device;
   UInt64 session;
@@ -293,6 +294,17 @@ static void darwin_devices_detached (void *ptr, io_iterator_t rem_devices) {
     if (!ret)
       continue;
 
+    /* we need to match darwin_ref_cached_device call made in darwin_get_cached_device function
+       otherwise no cached device will ever get freed */
+    usbi_mutex_lock(&darwin_cached_devices_lock);
+    list_for_each_entry(old_device, &darwin_cached_devices, list, struct darwin_cached_device) {
+      if (old_device->session == session) {
+        darwin_deref_cached_device (old_device);
+        break;
+      }
+    }
+    usbi_mutex_unlock(&darwin_cached_devices_lock);
+
     list_for_each_entry(ctx, &active_contexts_list, list, struct libusb_context) {
       usbi_dbg ("notifying context %p of device disconnect", ctx);
 

diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index bafad24..4849396 100644 (file)
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 10959
+#define LIBUSB_NANO 10960