diff options
Diffstat (limited to 'libusb/descriptor.c')
| -rw-r--r-- | libusb/descriptor.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/libusb/descriptor.c b/libusb/descriptor.c index 727cf98..97e1d9a 100644 --- a/libusb/descriptor.c +++ b/libusb/descriptor.c @@ -1071,6 +1071,68 @@ void API_EXPORTED libusb_free_container_id_descriptor( } /** \ingroup libusb_desc + * Get a platform descriptor + * + * \param ctx the context to operate on, or NULL for the default context + * \param dev_cap Device Capability descriptor with a bDevCapabilityType of + * \ref libusb_capability_type::LIBUSB_BT_PLATFORM_DESCRIPTOR + * LIBUSB_BT_PLATFORM_DESCRIPTOR + * \param platform_descriptor output location for the Platform descriptor. + * Only valid if 0 was returned. Must be freed with + * libusb_free_platform_descriptor() after use. + * \returns 0 on success + * \returns a LIBUSB_ERROR code on error + */ +int API_EXPORTED libusb_get_platform_descriptor(libusb_context *ctx, + struct libusb_bos_dev_capability_descriptor *dev_cap, + struct libusb_platform_descriptor **platform_descriptor) +{ + struct libusb_platform_descriptor *_platform_descriptor; + + if (dev_cap->bDevCapabilityType != LIBUSB_BT_PLATFORM_DESCRIPTOR) { + usbi_err(ctx, "unexpected bDevCapabilityType 0x%x (expected 0x%x)", + dev_cap->bDevCapabilityType, + LIBUSB_BT_PLATFORM_DESCRIPTOR); + return LIBUSB_ERROR_INVALID_PARAM; + } else if (dev_cap->bLength < LIBUSB_BT_PLATFORM_DESCRIPTOR_MIN_SIZE) { + usbi_err(ctx, "short dev-cap descriptor read %u/%d", + dev_cap->bLength, LIBUSB_BT_PLATFORM_DESCRIPTOR_MIN_SIZE); + return LIBUSB_ERROR_IO; + } + + _platform_descriptor = malloc(dev_cap->bLength); + if (!_platform_descriptor) + return LIBUSB_ERROR_NO_MEM; + + parse_descriptor(dev_cap, "bbbbu", _platform_descriptor); + + /* Capability data is located after reserved byte and 128-bit UUID */ + uint8_t* capability_data = dev_cap->dev_capability_data + 1 + 16; + + /* Capability data length is total descriptor length minus initial fields */ + size_t capability_data_length = _platform_descriptor->bLength - (16 + 4); + + memcpy(_platform_descriptor->CapabilityData, capability_data, capability_data_length); + + *platform_descriptor = _platform_descriptor; + return LIBUSB_SUCCESS; +} + +/** \ingroup libusb_desc + * Free a platform descriptor obtained from + * libusb_get_platform_descriptor(). + * It is safe to call this function with a NULL platform_descriptor parameter, + * in which case the function simply returns. + * + * \param platform_descriptor the Platform descriptor to free + */ +void API_EXPORTED libusb_free_platform_descriptor( + struct libusb_platform_descriptor *platform_descriptor) +{ + free(platform_descriptor); +} + +/** \ingroup libusb_desc * Retrieve a string descriptor in C style ASCII. * * Wrapper around libusb_get_string_descriptor(). Uses the first language |