Try to read BOS and WebUSB descriptors from USB devices.

device/usb/usb_service_impl.cc

Index: device/usb/usb_service_impl.cc
diff --git a/device/usb/usb_service_impl.cc b/device/usb/usb_service_impl.cc
index 2261ad6930bdd1b246daf7e3abc957a9994131a9..b1eda6af99306ea5e493808229f3311ef48d637c 100644
--- a/device/usb/usb_service_impl.cc
+++ b/device/usb/usb_service_impl.cc
@@ -20,6 +20,7 @@
 #include "components/device_event_log/device_event_log.h"
 #include "device/usb/usb_device_handle.h"
 #include "device/usb/usb_error.h"
+#include "device/usb/webusb_descriptors.h"
 #include "third_party/libusb/src/libusb/libusb.h"
 
 #if defined(OS_WIN)
@@ -33,10 +34,24 @@
 #include "device/udev_linux/scoped_udev.h"
 #endif  // USE_UDEV
 
+using net::IOBufferWithSize;
+
 namespace device {
 
 namespace {
 
+// Standard USB requests and descriptor types:
+const uint8_t kGetDescriptorRequest = 0x06;
+const uint8_t kStringDescriptorType = 0x03;
+const uint8_t kBosDescriptorType = 0x0F;
+
+// WebUSB requests:
+const uint8_t kGetAllowedOriginsRequest = 0x01;
+const uint8_t kGetLandingPageRequest = 0x02;
+const uint8_t kUrlDescriptorType = 0x03;
+
+const int kControlTransferTimeout = 60000; /* 1 minute */

[Ken Rockot(use gerrit already), 2015/08/04 01:15:01]

nit: a cursory grep through the repo suggests you should use the
two-spaces-and-one-line-comment style rather than /* this */

[Reilly Grant (use Gerrit), 2015/08/04 20:48:56]

Done.

+
 #if defined(OS_WIN)
 
 // Wrapper around a HDEVINFO that automatically destroys it.
@@ -165,71 +180,6 @@ void GetDeviceListOnBlockingThread(
                         base::Bind(callback, platform_devices, device_count));
 }
 
-#if defined(USE_UDEV)
-
-void EnumerateUdevDevice(scoped_refptr<UsbDeviceImpl> device,
-                         scoped_refptr<base::SequencedTaskRunner> task_runner,
-                         const base::Closure& success_closure,
-                         const base::Closure& failure_closure) {
-  ScopedUdevPtr udev(udev_new());
-  ScopedUdevEnumeratePtr udev_enumerate(udev_enumerate_new(udev.get()));
-
-  udev_enumerate_add_match_subsystem(udev_enumerate.get(), "usb");
-  if (udev_enumerate_scan_devices(udev_enumerate.get()) != 0) {
-    task_runner->PostTask(FROM_HERE, failure_closure);
-    return;
-  }
-
-  std::string bus_number =
-      base::IntToString(libusb_get_bus_number(device->platform_device()));
-  std::string device_address =
-      base::IntToString(libusb_get_device_address(device->platform_device()));
-  udev_list_entry* devices =
-      udev_enumerate_get_list_entry(udev_enumerate.get());
-  for (udev_list_entry* i = devices; i != NULL;
-       i = udev_list_entry_get_next(i)) {
-    ScopedUdevDevicePtr udev_device(
-        udev_device_new_from_syspath(udev.get(), udev_list_entry_get_name(i)));
-    if (udev_device) {
-      const char* value =
-          udev_device_get_sysattr_value(udev_device.get(), "busnum");
-      if (!value || bus_number != value) {
-        continue;
-      }
-      value = udev_device_get_sysattr_value(udev_device.get(), "devnum");
-      if (!value || device_address != value) {
-        continue;
-      }
-
-      value = udev_device_get_sysattr_value(udev_device.get(), "manufacturer");
-      if (value) {
-        device->set_manufacturer_string(base::UTF8ToUTF16(value));
-      }
-      value = udev_device_get_sysattr_value(udev_device.get(), "product");
-      if (value) {
-        device->set_product_string(base::UTF8ToUTF16(value));
-      }
-      value = udev_device_get_sysattr_value(udev_device.get(), "serial");
-      if (value) {
-        device->set_serial_number(base::UTF8ToUTF16(value));
-      }
-
-      value = udev_device_get_devnode(udev_device.get());
-      if (value) {
-        device->set_device_path(value);
-        task_runner->PostTask(FROM_HERE, success_closure);
-        return;
-      }
-
-      break;
-    }
-  }
-
-  task_runner->PostTask(FROM_HERE, failure_closure);
-}
-
-#else
-
 void OnReadStringDescriptor(
     const base::Callback<void(const base::string16&)>& callback,
     UsbTransferStatus status,
@@ -254,11 +204,157 @@ void ReadStringDescriptor(
     uint8 index,
     uint16 language_id,
     const base::Callback<void(const base::string16&)>& callback) {
-  scoped_refptr<net::IOBuffer> buffer = new net::IOBuffer(256);
+  scoped_refptr<IOBufferWithSize> buffer = new IOBufferWithSize(256);
+  device_handle->ControlTransfer(
+      USB_DIRECTION_INBOUND, UsbDeviceHandle::STANDARD, UsbDeviceHandle::DEVICE,
+      kGetDescriptorRequest, kStringDescriptorType << 8 | index, language_id,
+      buffer, buffer->size(), kControlTransferTimeout,
+      base::Bind(&OnReadStringDescriptor, callback));
+}
+
+void OnReadWebUsbLandingPage(scoped_refptr<UsbDevice> device,
+                             const base::Closure& callback,
+                             UsbTransferStatus status,
+                             scoped_refptr<net::IOBuffer> buffer,
+                             size_t length) {
+  if (status != USB_TRANSFER_COMPLETED || length < 2) {
+    callback.Run();
+    return;
+  }
+
+  uint8_t string_length = buffer->data()[0];
+  if (string_length < 2 || string_length > length ||
+      buffer->data()[1] != kUrlDescriptorType) {
+    callback.Run();
+    return;
+  }
+
+  GURL url(std::string(&buffer->data()[2], string_length - 2));
+  if (url.is_valid()) {
+    UsbDeviceImpl* device_impl = static_cast<UsbDeviceImpl*>(device.get());
+    device_impl->set_webusb_landing_page(url);
+  }
+  callback.Run();
+}
+
+void ReadWebUsbLandingPage(scoped_refptr<UsbDeviceHandle> device_handle,
+                           const base::Closure& callback,
+                           uint8 vendor_code) {
+  scoped_refptr<IOBufferWithSize> buffer = new IOBufferWithSize(256);
+  device_handle->ControlTransfer(
+      USB_DIRECTION_INBOUND, UsbDeviceHandle::VENDOR, UsbDeviceHandle::DEVICE,
+      vendor_code, 0, kGetLandingPageRequest, buffer, buffer->size(),
+      kControlTransferTimeout,
+      base::Bind(&OnReadWebUsbLandingPage, device_handle->GetDevice(),
+                 callback));
+}
+
+void OnReadWebUsbAllowedOrigins(scoped_refptr<UsbDevice> device,
+                                const base::Closure& callback,
+                                UsbTransferStatus status,
+                                scoped_refptr<net::IOBuffer> buffer,
+                                size_t length) {
+  if (status != USB_TRANSFER_COMPLETED) {
+    USB_LOG(EVENT) << "Failed to read WebUSB allowed origins.";
+    callback.Run();
+    return;
+  }
+
+  scoped_ptr<WebUsbDescriptorSet> descriptors(new WebUsbDescriptorSet());
+  if (descriptors->Parse(
+          std::vector<uint8>(buffer->data(), buffer->data() + length))) {
+    UsbDeviceImpl* device_impl = static_cast<UsbDeviceImpl*>(device.get());
+    device_impl->set_webusb_allowed_origins(descriptors.Pass());
+  }
+  callback.Run();
+}
+
+void OnReadWebUsbAllowedOriginsHeader(
+    scoped_refptr<UsbDeviceHandle> device_handle,
+    const base::Closure& callback,
+    uint8 vendor_code,
+    UsbTransferStatus status,
+    scoped_refptr<net::IOBuffer> buffer,
+    size_t length) {
+  if (status != USB_TRANSFER_COMPLETED || length != 4) {
+    USB_LOG(EVENT) << "Failed to read WebUSB allowed origins header.";
+    callback.Run();
+    return;
+  }
+
+  uint16 new_length = buffer->data()[2] | (buffer->data()[3] << 8);
+  scoped_refptr<IOBufferWithSize> new_buffer = new IOBufferWithSize(new_length);
+  device_handle->ControlTransfer(
+      USB_DIRECTION_INBOUND, UsbDeviceHandle::VENDOR, UsbDeviceHandle::DEVICE,
+      vendor_code, 0, kGetAllowedOriginsRequest, new_buffer, new_buffer->size(),
+      kControlTransferTimeout,
+      base::Bind(&OnReadWebUsbAllowedOrigins, device_handle->GetDevice(),
+                 callback));
+}
+
+void ReadWebUsbAllowedOrigins(scoped_refptr<UsbDeviceHandle> device_handle,
+                              const base::Closure& callback,
+                              uint8 vendor_code) {
+  scoped_refptr<IOBufferWithSize> buffer = new IOBufferWithSize(4);
+  device_handle->ControlTransfer(
+      USB_DIRECTION_INBOUND, UsbDeviceHandle::VENDOR, UsbDeviceHandle::DEVICE,
+      vendor_code, 0, kGetAllowedOriginsRequest, buffer, buffer->size(),
+      kControlTransferTimeout,
+      base::Bind(&OnReadWebUsbAllowedOriginsHeader, device_handle, callback,
+                 vendor_code));
+}
+
+void OnReadBosDescriptor(scoped_refptr<UsbDeviceHandle> device_handle,
+                         const base::Closure& callback,
+                         UsbTransferStatus status,
+                         scoped_refptr<net::IOBuffer> buffer,
+                         size_t length) {
+  if (status != USB_TRANSFER_COMPLETED) {
+    USB_LOG(EVENT) << "Failed to read BOS descriptor.";
+    callback.Run();
+    return;
+  }
+
+  WebUsbPlatformCapabilityDescriptor descriptor;
+  if (!descriptor.ParseFromBosDescriptor(
+          std::vector<uint8>(buffer->data(), buffer->data() + length))) {
+    callback.Run();
+    return;
+  }
+
+  base::Closure barrier = base::BarrierClosure(2, callback);
+  ReadWebUsbLandingPage(device_handle, barrier, descriptor.vendor_code);
+  ReadWebUsbAllowedOrigins(device_handle, barrier, descriptor.vendor_code);
+}
+
+void OnReadBosDescriptorHeader(scoped_refptr<UsbDeviceHandle> device_handle,
+                               const base::Closure& callback,
+                               UsbTransferStatus status,
+                               scoped_refptr<net::IOBuffer> buffer,
+                               size_t length) {
+  if (status != USB_TRANSFER_COMPLETED || length != 5) {
+    USB_LOG(EVENT) << "Failed to read BOS descriptor header.";
+    callback.Run();
+    return;
+  }
+
+  uint16 new_length = buffer->data()[2] | (buffer->data()[3] << 8);
+  scoped_refptr<IOBufferWithSize> new_buffer = new IOBufferWithSize(new_length);
+  device_handle->ControlTransfer(

[Ken Rockot(use gerrit already), 2015/08/04 01:15:01]

nit: maaaaybe it's worth adding a utility method to UsbDeviceHandle just because
there's a lot of repetition of the same basic control transfer operation (i.e.
read a string descriptor)

+      USB_DIRECTION_INBOUND, UsbDeviceHandle::STANDARD, UsbDeviceHandle::DEVICE,
+      kGetDescriptorRequest, kBosDescriptorType << 8, 0, new_buffer,
+      new_buffer->size(), kControlTransferTimeout,
+      base::Bind(&OnReadBosDescriptor, device_handle, callback));
+}
+
+void ReadBosDescriptor(scoped_refptr<UsbDeviceHandle> device_handle,
+                       const base::Closure& callback) {
+  scoped_refptr<IOBufferWithSize> buffer = new IOBufferWithSize(5);
   device_handle->ControlTransfer(
       USB_DIRECTION_INBOUND, UsbDeviceHandle::STANDARD, UsbDeviceHandle::DEVICE,
-      6 /* GET_DESCRIPTOR */, 3 /* STRING */ << 8 | index, language_id, buffer,
-      256, 60, base::Bind(&OnReadStringDescriptor, callback));
+      kGetDescriptorRequest, kBosDescriptorType << 8, 0, buffer, buffer->size(),
+      kControlTransferTimeout,
+      base::Bind(&OnReadBosDescriptorHeader, device_handle, callback));
 }
 
 void CloseHandleAndRunContinuation(scoped_refptr<UsbDeviceHandle> device_handle,
@@ -277,11 +373,12 @@ void SaveStringAndRunContinuation(
   continuation.Run();
 }
 
+// This function runs |barrier| once for every string it tries to read.
 void OnReadLanguageIds(scoped_refptr<UsbDeviceHandle> device_handle,
                        uint8 manufacturer,
                        uint8 product,
                        uint8 serial_number,
-                       const base::Closure& success_closure,
+                       const base::Closure& barrier,
                        const base::string16& languages) {
   // Default to English unless the device provides a language and then just pick
   // the first one.
@@ -292,57 +389,143 @@ void OnReadLanguageIds(scoped_refptr<UsbDeviceHandle> device_handle,
 
   scoped_refptr<UsbDeviceImpl> device =
       static_cast<UsbDeviceImpl*>(device_handle->GetDevice().get());
-  base::Closure continuation =
-      base::BarrierClosure(3, base::Bind(&CloseHandleAndRunContinuation,
-                                         device_handle, success_closure));
 
-  if (manufacturer == 0) {
-    continuation.Run();
-  } else {
+  if (manufacturer != 0) {
     ReadStringDescriptor(
         device_handle, manufacturer, language_id,
         base::Bind(&SaveStringAndRunContinuation,
                    base::Bind(&UsbDeviceImpl::set_manufacturer_string, device),
-                   continuation));
+                   barrier));
   }
 
-  if (product == 0) {
-    continuation.Run();
-  } else {
+  if (product != 0) {
     ReadStringDescriptor(
         device_handle, product, language_id,
         base::Bind(&SaveStringAndRunContinuation,
                    base::Bind(&UsbDeviceImpl::set_product_string, device),
-                   continuation));
+                   barrier));
   }
 
-  if (serial_number == 0) {
-    continuation.Run();
-  } else {
+  if (serial_number != 0) {
     ReadStringDescriptor(
         device_handle, serial_number, language_id,
         base::Bind(&SaveStringAndRunContinuation,
                    base::Bind(&UsbDeviceImpl::set_serial_number, device),
-                   continuation));
+                   barrier));
   }
 }
 
-void ReadDeviceLanguage(uint8 manufacturer,
-                        uint8 product,
-                        uint8 serial_number,
-                        const base::Closure& success_closure,
-                        const base::Closure& failure_closure,
-                        scoped_refptr<UsbDeviceHandle> device_handle) {
+void OnDeviceOpenedReadDescriptors(
+    uint8 manufacturer,
+    uint8 product,
+    uint8 serial_number,
+    bool read_bos_descriptors,
+    const base::Closure& success_closure,
+    const base::Closure& failure_closure,
+    scoped_refptr<UsbDeviceHandle> device_handle) {
   if (device_handle) {
-    ReadStringDescriptor(
-        device_handle, 0, 0,
-        base::Bind(&OnReadLanguageIds, device_handle, manufacturer, product,
-                   serial_number, success_closure));
+    size_t count = 0;
+    if (manufacturer != 0)
+      count++;
+    if (product != 0)
+      count++;
+    if (serial_number != 0)
+      count++;
+    if (read_bos_descriptors)
+      count++;
+
+    base::Closure barrier =
+        base::BarrierClosure(count, base::Bind(&CloseHandleAndRunContinuation,
+                                               device_handle, success_closure));
+
+    if (manufacturer != 0 || product != 0 || serial_number != 0) {
+      ReadStringDescriptor(
+          device_handle, 0, 0,
+          base::Bind(&OnReadLanguageIds, device_handle, manufacturer, product,
+                     serial_number, barrier));
+    }
+
+    if (read_bos_descriptors) {
+      ReadBosDescriptor(device_handle, barrier);
+    }
   } else {
     failure_closure.Run();
   }
 }
 
+#if defined(USE_UDEV)
+
+void EnumerateUdevDevice(scoped_refptr<UsbDeviceImpl> device,
+                         bool read_bos_descriptors,
+                         scoped_refptr<base::SequencedTaskRunner> task_runner,
+                         const base::Closure& success_closure,
+                         const base::Closure& failure_closure) {
+  ScopedUdevPtr udev(udev_new());
+  ScopedUdevEnumeratePtr udev_enumerate(udev_enumerate_new(udev.get()));
+
+  udev_enumerate_add_match_subsystem(udev_enumerate.get(), "usb");
+  if (udev_enumerate_scan_devices(udev_enumerate.get()) != 0) {
+    task_runner->PostTask(FROM_HERE, failure_closure);
+    return;
+  }
+
+  std::string bus_number =
+      base::IntToString(libusb_get_bus_number(device->platform_device()));
+  std::string device_address =
+      base::IntToString(libusb_get_device_address(device->platform_device()));
+  udev_list_entry* devices =
+      udev_enumerate_get_list_entry(udev_enumerate.get());
+  for (udev_list_entry* i = devices; i != NULL;
+       i = udev_list_entry_get_next(i)) {
+    ScopedUdevDevicePtr udev_device(
+        udev_device_new_from_syspath(udev.get(), udev_list_entry_get_name(i)));
+    if (udev_device) {
+      const char* value =
+          udev_device_get_sysattr_value(udev_device.get(), "busnum");
+      if (!value || bus_number != value) {
+        continue;
+      }
+      value = udev_device_get_sysattr_value(udev_device.get(), "devnum");
+      if (!value || device_address != value) {
+        continue;
+      }
+
+      value = udev_device_get_sysattr_value(udev_device.get(), "manufacturer");
+      if (value) {
+        device->set_manufacturer_string(base::UTF8ToUTF16(value));
+      }
+      value = udev_device_get_sysattr_value(udev_device.get(), "product");
+      if (value) {
+        device->set_product_string(base::UTF8ToUTF16(value));
+      }
+      value = udev_device_get_sysattr_value(udev_device.get(), "serial");
+      if (value) {
+        device->set_serial_number(base::UTF8ToUTF16(value));
+      }
+
+      value = udev_device_get_devnode(udev_device.get());
+      if (value) {
+        device->set_device_path(value);
+
+        if (read_bos_descriptors) {
+          task_runner->PostTask(
+              FROM_HERE,
+              base::Bind(&UsbDevice::Open, device,
+                         base::Bind(&OnDeviceOpenedReadDescriptors, 0, 0, 0,
+                                    true, success_closure, failure_closure)));
+        } else {
+          task_runner->PostTask(FROM_HERE, success_closure);
+        }
+        return;
+      }
+
+      break;
+    }
+  }
+
+  task_runner->PostTask(FROM_HERE, failure_closure);
+}
+
 #endif  // USE_UDEV
 
 }  // namespace
@@ -573,20 +756,22 @@ void UsbServiceImpl::EnumerateDevice(PlatformUsbDevice platform_device,
     base::Closure add_device =
         base::Bind(&UsbServiceImpl::AddDevice, weak_factory_.GetWeakPtr(),
                    refresh_complete, device);
+    bool read_bos_descriptors = descriptor.bcdUSB >= 0x0210;

[Ken Rockot(use gerrit already), 2015/08/04 01:15:01]

nit: add a named constant for 0x210?

[Reilly Grant (use Gerrit), 2015/08/04 20:48:56]

Done.

 
 #if defined(USE_UDEV)
     blocking_task_runner_->PostTask(
-        FROM_HERE, base::Bind(&EnumerateUdevDevice, device, task_runner_,
-                              add_device, refresh_complete));
+        FROM_HERE,
+        base::Bind(&EnumerateUdevDevice, device, read_bos_descriptors,
+                   task_runner_, add_device, refresh_complete));
 #else
     if (descriptor.iManufacturer == 0 && descriptor.iProduct == 0 &&
-        descriptor.iSerialNumber == 0) {
-      // Don't bother disturbing the device if it has no string descriptors to
-      // offer.
+        descriptor.iSerialNumber == 0 && !read_bos_descriptors) {
+      // Don't bother disturbing the device if it has no descriptors to offer.
       add_device.Run();
     } else {
-      device->Open(base::Bind(&ReadDeviceLanguage, descriptor.iManufacturer,
-                              descriptor.iProduct, descriptor.iSerialNumber,
+      device->Open(base::Bind(&OnDeviceOpenedReadDescriptors,
+                              descriptor.iManufacturer, descriptor.iProduct,
+                              descriptor.iSerialNumber, read_bos_descriptors,
                               add_device, refresh_complete));
     }
 #endif