darwin: updates to support el capitan

With the new USB stack Apple changed the underlying device class from
IOUSBDevice to IOUSBHostDevice. Additionally, they removed the PortNum
property from the IO registry entry. This commit add code to detect the
currently running xnu version. If the version is at least 15 (10.11.0)
the new device class is used to find usb devices and the port number
is read from the IOService parent of the USB device instead of the
PortNum property.

Closes #127

May have some effect on either #123 or #96.

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

2 files changed, 78 insertions, 6 deletions

diff --git a/libusb/os/darwin_usb.c b/libusb/os/darwin_usb.c
index 26d0cff..b107e4d 100644
--- a/libusb/os/darwin_usb.c
+++ b/libusb/os/darwin_usb.c
@@ -29,6 +29,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <libkern/OSAtomic.h>
+#include <sys/sysctl.h>
 
 #include <mach/clock.h>
 #include <mach/clock_types.h>
@@ -46,6 +47,8 @@
 static pthread_mutex_t libusb_darwin_at_mutex = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t  libusb_darwin_at_cond = PTHREAD_COND_INITIALIZER;
 
+static pthread_once_t darwin_init_once = PTHREAD_ONCE_INIT;
+
 static clock_serv_t clock_realtime;
 static clock_serv_t clock_monotonic;
 
@@ -54,6 +57,7 @@ static volatile int32_t initCount = 0;
 
 static usbi_mutex_t darwin_cached_devices_lock = PTHREAD_MUTEX_INITIALIZER;
 static struct list_head darwin_cached_devices = {&darwin_cached_devices, &darwin_cached_devices};
+static char *darwin_device_class = kIOUSBDeviceClassName;
 
 #define DARWIN_CACHED_DEVICE(a) ((struct darwin_cached_device *) (((struct darwin_device_priv *)((a)->os_priv))->dev))
 
@@ -189,7 +193,7 @@ static int ep_to_pipeRef(struct libusb_device_handle *dev_handle, uint8_t ep, ui
 }
 
 static int usb_setup_device_iterator (io_iterator_t *deviceIterator, UInt32 location) {
-  CFMutableDictionaryRef matchingDict = IOServiceMatching(kIOUSBDeviceClassName);
+  CFMutableDictionaryRef matchingDict = IOServiceMatching(darwin_device_class);
 
   if (!matchingDict)
     return kIOReturnError;
@@ -234,6 +238,27 @@ static int get_ioregistry_value_number (io_service_t service, CFStringRef proper
   return ret;
 }
 
+static int get_ioregistry_value_data (io_service_t service, CFStringRef property, size_t size, void *p) {
+  CFTypeRef cfData = IORegistryEntryCreateCFProperty (service, property, kCFAllocatorDefault, 0);
+  int ret = 0;
+
+  if (cfData) {
+    if (CFGetTypeID (cfData) == CFDataGetTypeID ()) {
+      CFIndex length = CFDataGetLength (cfData);
+      if (length < size) {
+        size = length;
+      }
+
+      CFDataGetBytes (cfData, CFRangeMake(0, size), p);
+      ret = 1;
+    }
+
+    CFRelease (cfData);
+  }
+
+  return ret;
+}
+
 static usb_device_t **darwin_device_from_service (io_service_t service)
 {
   io_cf_plugin_ref_t *plugInInterface = NULL;
@@ -374,7 +399,7 @@ static void *darwin_event_thread_main (void *arg0) {
 
   /* create notifications for removed devices */
   kresult = IOServiceAddMatchingNotification (libusb_notification_port, kIOTerminatedNotification,
-                                              IOServiceMatching(kIOUSBDeviceClassName),
+                                              IOServiceMatching(darwin_device_class),
                                               darwin_devices_detached,
                                               ctx, &libusb_rem_device_iterator);
 
@@ -386,7 +411,7 @@ static void *darwin_event_thread_main (void *arg0) {
 
   /* create notifications for attached devices */
   kresult = IOServiceAddMatchingNotification(libusb_notification_port, kIOFirstMatchNotification,
-                                              IOServiceMatching(kIOUSBDeviceClassName),
+                                              IOServiceMatching(darwin_device_class),
                                               darwin_devices_attached,
                                               ctx, &libusb_add_device_iterator);
 
@@ -441,10 +466,31 @@ static void __attribute__((destructor)) _darwin_finalize(void) {
   usbi_mutex_unlock(&darwin_cached_devices_lock);
 }
 
+static void darwin_check_version (void) {
+  /* adjust for changes in the USB stack in xnu 15 */
+  int sysctl_args[] = {CTL_KERN, KERN_OSRELEASE};
+  long version;
+  char version_string[256] = {'\0',};
+  size_t length = 256;
+
+  sysctl(sysctl_args, 2, version_string, &length, NULL, 0);
+
+  errno = 0;
+  version = strtol (version_string, NULL, 10);
+  if (0 == errno && version >= 15) {
+    darwin_device_class = "IOUSBHostDevice";
+  }
+}
+
 static int darwin_init(struct libusb_context *ctx) {
   host_name_port_t host_self;
   int rc;
 
+  rc = pthread_once (&darwin_init_once, darwin_check_version);
+  if (rc) {
+    return LIBUSB_ERROR_OTHER;
+  }
+
   rc = darwin_scan_devices (ctx);
   if (LIBUSB_SUCCESS != rc) {
     return rc;
@@ -768,6 +814,24 @@ static int darwin_cache_device_descriptor (struct libusb_context *ctx, struct da
   return LIBUSB_SUCCESS;
 }
 
+static int get_device_port (io_service_t service, UInt8 *port) {
+  kern_return_t result;
+  io_service_t parent;
+  int ret = 0;
+
+  if (get_ioregistry_value_number (service, CFSTR("PortNum"), kCFNumberSInt8Type, port)) {
+    return 1;
+  }
+
+  result = IORegistryEntryGetParentEntry (service, kIOServicePlane, &parent);
+  if (kIOReturnSuccess == result) {
+    ret = get_ioregistry_value_data (parent, CFSTR("port"), 1, port);
+    IOObjectRelease (parent);
+  }
+
+  return ret;
+}
+
 static int darwin_get_cached_device(struct libusb_context *ctx, io_service_t service,
                                     struct darwin_cached_device **cached_out) {
   struct darwin_cached_device *new_device;
@@ -780,7 +844,9 @@ static int darwin_get_cached_device(struct libusb_context *ctx, io_service_t ser
 
   /* get some info from the io registry */
   (void) get_ioregistry_value_number (service, CFSTR("sessionID"), kCFNumberSInt64Type, &sessionID);
-  (void) get_ioregistry_value_number (service, CFSTR("PortNum"), kCFNumberSInt8Type, &port);
+  if (!get_device_port (service, &port)) {
+    usbi_dbg("could not get connected port number");
+  }
 
   usbi_dbg("finding cached device for sessionID 0x%" PRIx64, sessionID);
 
diff --git a/libusb/os/darwin_usb.h b/libusb/os/darwin_usb.h
index 4cf28bf..1180434 100644
--- a/libusb/os/darwin_usb.h
+++ b/libusb/os/darwin_usb.h
@@ -1,6 +1,6 @@
 /*
  * darwin backend for libusb 1.0
- * Copyright © 2008-2013 Nathan Hjelm <hjelmn@users.sourceforge.net>
+ * Copyright © 2008-2015 Nathan Hjelm <hjelmn@users.sourceforge.net>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -28,7 +28,13 @@
 #include <IOKit/IOCFPlugIn.h>
 
 /* IOUSBInterfaceInferface */
-#if defined (kIOUSBInterfaceInterfaceID550) && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_9
+#if defined (kIOUSBInterfaceInterfaceID700) && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_9
+
+#define usb_interface_t IOUSBInterfaceInterface700
+#define InterfaceInterfaceID kIOUSBInterfaceInterfaceID700
+#define InterfaceVersion 700
+
+#elif defined (kIOUSBInterfaceInterfaceID550) && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_9
 
 #define usb_interface_t IOUSBInterfaceInterface550
 #define InterfaceInterfaceID kIOUSBInterfaceInterfaceID550