1 files changed, 111 insertions, 35 deletions

diff --git a/src/usb.c b/src/usb.c
index e0fadfd..88d781d 100644
--- a/src/usb.c
+++ b/src/usb.c
@@ -61,6 +61,7 @@ struct usb_device {
         int wMaxPacketSize;
         uint64_t speed;
         struct libusb_device_descriptor devdesc;
+        unsigned char transfer_buffer[1024 + LIBUSB_CONTROL_SETUP_SIZE];
 };
 
 static struct collection device_list;
@@ -258,6 +259,91 @@ static int start_rx_loop(struct usb_device *dev)
         return 0;
 }
 
+static void get_serial_callback(struct libusb_transfer *transfer)
+{
+        unsigned int di, si;
+        struct usb_device *usbdev = transfer->user_data;
+
+        if(transfer->status != LIBUSB_TRANSFER_COMPLETED) {
+                usbmuxd_log(LL_ERROR, "Failed to request serial for device %d-%d (%i)", usbdev->bus, usbdev->address, transfer->status);
+                libusb_free_transfer(transfer);
+                return;
+        }
+
+        /* De-unicode, taken from libusb */
+        unsigned char *data = libusb_control_transfer_get_data(transfer);
+        for (di = 0, si = 2; si < data[0] && di < sizeof(usbdev->serial)-1; si += 2) {
+                if ((data[si] & 0x80) || (data[si + 1])) /* non-ASCII */
+                        usbdev->serial[di++] = '?';
+                else
+                        usbdev->serial[di++] = data[si];
+        }
+        usbdev->serial[di] = 0;
+
+        usbmuxd_log(LL_INFO, "Got serial '%s' for device %d-%d", usbdev->serial, usbdev->bus, usbdev->address);
+
+        libusb_free_transfer(transfer);
+
+        /* Finish setup now */
+        if(device_add(usbdev) < 0) {
+                usb_disconnect(usbdev);
+                return;
+        }
+
+        // Spin up NUM_RX_LOOPS parallel usb data retrieval loops
+        // Old usbmuxds used only 1 rx loop, but that leaves the
+        // USB port sleeping most of the time
+        int rx_loops = NUM_RX_LOOPS;
+        for (rx_loops = NUM_RX_LOOPS; rx_loops > 0; rx_loops--) {
+                if(start_rx_loop(usbdev) < 0) {
+                        usbmuxd_log(LL_WARNING, "Failed to start RX loop number %d", NUM_RX_LOOPS - rx_loops);
+                }
+        }
+
+        // Ensure we have at least 1 RX loop going
+        if (rx_loops == NUM_RX_LOOPS) {
+                usbmuxd_log(LL_FATAL, "Failed to start any RX loop for device %d-%d",
+                                        usbdev->bus, usbdev->address);
+                device_remove(usbdev);
+                usb_disconnect(usbdev);
+                return;
+        } else if (rx_loops > 0) {
+                usbmuxd_log(LL_WARNING, "Failed to start all %d RX loops. Going on with %d loops. "
+                                        "This may have negative impact on device read speed.",
+                                        NUM_RX_LOOPS, NUM_RX_LOOPS - rx_loops);
+        } else {
+                usbmuxd_log(LL_DEBUG, "All %d RX loops started successfully", NUM_RX_LOOPS);
+        }
+}
+
+static void get_langid_callback(struct libusb_transfer *transfer)
+{
+        int res;
+        struct usb_device *usbdev = transfer->user_data;
+
+        if(transfer->status != LIBUSB_TRANSFER_COMPLETED) {
+                 usbmuxd_log(LL_ERROR, "Failed to request lang ID for device %d-%d (%i)", usbdev->bus,
+                                 usbdev->address, transfer->status);
+                 libusb_free_transfer(transfer);
+                 return;
+        }
+
+        unsigned char *data = libusb_control_transfer_get_data(transfer);
+        uint16_t langid = (uint16_t)(data[2] | (data[3] << 8));
+        usbmuxd_log(LL_INFO, "Got lang ID %u for device %d-%d", langid, usbdev->bus, usbdev->address);
+
+        /* re-use the same transfer */
+        libusb_fill_control_setup(usbdev->transfer_buffer, LIBUSB_ENDPOINT_IN, LIBUSB_REQUEST_GET_DESCRIPTOR,
+                        (uint16_t)((LIBUSB_DT_STRING << 8) | usbdev->devdesc.iSerialNumber),
+                        langid, sizeof(usbdev->transfer_buffer));
+        libusb_fill_control_transfer(transfer, usbdev->dev, usbdev->transfer_buffer, get_serial_callback, usbdev, 1000);
+
+        if((res = libusb_submit_transfer(transfer)) < 0) {
+                usbmuxd_log(LL_ERROR, "Could not request transfer for device %d-%d (%d)", usbdev->bus, usbdev->address, res);
+                libusb_free_transfer(transfer);
+        }
+}
+
 static int usb_device_add(libusb_device* dev)
 {
         int j, res;
@@ -265,6 +351,7 @@ static int usb_device_add(libusb_device* dev)
         uint8_t bus = libusb_get_bus_number(dev);
         uint8_t address = libusb_get_device_address(dev);
         struct libusb_device_descriptor devdesc;
+        struct libusb_transfer *transfer;
         int found = 0;
         FOREACH(struct usb_device *usbdev, &device_list) {
                 if(usbdev->bus == bus && usbdev->address == address) {
@@ -287,7 +374,8 @@ static int usb_device_add(libusb_device* dev)
                 return -1;
         libusb_device_handle *handle;
         usbmuxd_log(LL_INFO, "Found new device with v/p %04x:%04x at %d-%d", devdesc.idVendor, devdesc.idProduct, bus, address);
-        // potentially blocking operations follow; they will only run when new devices are detected, which is acceptable
+        // No blocking operation can follow: it may be run in the libusb hotplug callback and libusb will refuse any
+        // blocking call
         if((res = libusb_open(dev, &handle)) != 0) {
                 usbmuxd_log(LL_WARNING, "Could not open device %d-%d: %d", bus, address, res);
                 return -1;
@@ -386,14 +474,15 @@ static int usb_device_add(libusb_device* dev)
                 return -1;
         }
 
-        if((res = libusb_get_string_descriptor_ascii(handle, devdesc.iSerialNumber, (uint8_t *)usbdev->serial, 256)) <= 0) {
-                usbmuxd_log(LL_WARNING, "Could not get serial number for device %d-%d: %d", bus, address, res);
-                libusb_release_interface(handle, usbdev->interface);
+        transfer = libusb_alloc_transfer(0);
+        if(!transfer) {
+                usbmuxd_log(LL_WARNING, "Failed to allocate transfer for device %d-%d: %d", bus, address, res);
                 libusb_close(handle);
                 free(usbdev);
                 return -1;
         }
-        usbdev->serial[res] = 0;
+
+        usbdev->serial[0] = 0;
         usbdev->bus = bus;
         usbdev->address = address;
         usbdev->devdesc = devdesc;
@@ -427,40 +516,27 @@ static int usb_device_add(libusb_device* dev)
 
         usbmuxd_log(LL_INFO, "USB Speed is %g MBit/s for device %d-%d", (double)(usbdev->speed / 1000000.0), usbdev->bus, usbdev->address);
 
-        collection_init(&usbdev->tx_xfers);
-        collection_init(&usbdev->rx_xfers);
-
-        collection_add(&device_list, usbdev);
-
-        if(device_add(usbdev) < 0) {
-                usb_disconnect(usbdev);
+        /**
+         * From libusb:
+         *      Asking for the zero'th index is special - it returns a string
+         *      descriptor that contains all the language IDs supported by the
+         *      device.
+         **/
+        libusb_fill_control_setup(usbdev->transfer_buffer, LIBUSB_ENDPOINT_IN, LIBUSB_REQUEST_GET_DESCRIPTOR, LIBUSB_DT_STRING << 8, 0, sizeof(usbdev->transfer_buffer));
+        libusb_fill_control_transfer(transfer, handle, usbdev->transfer_buffer, get_langid_callback, usbdev, 1000);
+
+        if((res = libusb_submit_transfer(transfer)) < 0) {
+                usbmuxd_log(LL_ERROR, "Could not request transfer for device %d-%d (%d)", usbdev->bus, usbdev->address, res);
+                libusb_free_transfer(transfer);
+                libusb_close(handle);
+                free(usbdev);
                 return -1;
         }
 
-        // Spin up NUM_RX_LOOPS parallel usb data retrieval loops
-        // Old usbmuxds used only 1 rx loop, but that leaves the
-        // USB port sleeping most of the time
-        int rx_loops = NUM_RX_LOOPS;
-        for (rx_loops = NUM_RX_LOOPS; rx_loops > 0; rx_loops--) {
-                if(start_rx_loop(usbdev) < 0) {
-                        usbmuxd_log(LL_WARNING, "Failed to start RX loop number %d", NUM_RX_LOOPS - rx_loops);
-                }
-        }
+        collection_init(&usbdev->tx_xfers);
+        collection_init(&usbdev->rx_xfers);
 
-        // Ensure we have at least 1 RX loop going
-        if (rx_loops == NUM_RX_LOOPS) {
-                usbmuxd_log(LL_FATAL, "Failed to start any RX loop for device %d-%d",
-                                        usbdev->bus, usbdev->address);
-                device_remove(usbdev);
-                usb_disconnect(usbdev);
-                return -1;
-        } else if (rx_loops > 0) {
-                usbmuxd_log(LL_WARNING, "Failed to start all %d RX loops. Going on with %d loops. "
-                                        "This may have negative impact on device read speed.",
-                                        NUM_RX_LOOPS, NUM_RX_LOOPS - rx_loops);
-        } else {
-                usbmuxd_log(LL_DEBUG, "All %d RX loops started successfully", NUM_RX_LOOPS);
-        }
+        collection_add(&device_list, usbdev);
 
         return 0;
 }