diff options
Diffstat (limited to 'libusb/descriptor.c')
| -rw-r--r-- | libusb/descriptor.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/libusb/descriptor.c b/libusb/descriptor.c index 5cdacbb..727cf98 100644 --- a/libusb/descriptor.c +++ b/libusb/descriptor.c @@ -1137,3 +1137,188 @@ int API_EXPORTED libusb_get_string_descriptor_ascii(libusb_device_handle *dev_ha data[di] = 0; return di; } + +static int parse_iad_array(struct libusb_context *ctx, + struct libusb_interface_association_descriptor_array *iad_array, + const uint8_t *buffer, int size) +{ + uint8_t i; + struct usbi_descriptor_header header; + int consumed = 0; + const uint8_t *buf = buffer; + struct libusb_interface_association_descriptor *iad; + + if (size < LIBUSB_DT_CONFIG_SIZE) { + usbi_err(ctx, "short config descriptor read %d/%d", + size, LIBUSB_DT_CONFIG_SIZE); + return LIBUSB_ERROR_IO; + } + + // First pass: Iterate through desc list, count number of IADs + iad_array->length = 0; + while (consumed < size) { + parse_descriptor(buf, "bb", &header); + if (header.bDescriptorType == LIBUSB_DT_INTERFACE_ASSOCIATION) + iad_array->length++; + buf += header.bLength; + consumed += header.bLength; + } + + iad_array->iad = NULL; + if (iad_array->length > 0) { + iad = calloc(iad_array->length, sizeof(*iad)); + if (!iad) + return LIBUSB_ERROR_NO_MEM; + + iad_array->iad = iad; + + // Second pass: Iterate through desc list, fill IAD structures + consumed = 0; + i = 0; + while (consumed < size) { + parse_descriptor(buffer, "bb", &header); + if (header.bDescriptorType == LIBUSB_DT_INTERFACE_ASSOCIATION) + parse_descriptor(buffer, "bbbbbbbb", &iad[i++]); + buffer += header.bLength; + consumed += header.bLength; + } + } + + return LIBUSB_SUCCESS; +} + +static int raw_desc_to_iad_array(struct libusb_context *ctx, const uint8_t *buf, + int size, struct libusb_interface_association_descriptor_array **iad_array) +{ + struct libusb_interface_association_descriptor_array *_iad_array + = calloc(1, sizeof(*_iad_array)); + int r; + + if (!_iad_array) + return LIBUSB_ERROR_NO_MEM; + + r = parse_iad_array(ctx, _iad_array, buf, size); + if (r < 0) { + usbi_err(ctx, "parse_iad_array failed with error %d", r); + free(_iad_array); + return r; + } + + *iad_array = _iad_array; + return LIBUSB_SUCCESS; +} + +/** \ingroup libusb_desc + * Get an array of interface association descriptors (IAD) for a given + * configuration. + * This is a non-blocking function which does not involve any requests being + * sent to the device. + * + * \param dev a device + * \param config_index the index of the configuration you wish to retrieve the + * IADs for. + * \param iad_array output location for the array of IADs. Only valid if 0 was + * returned. Must be freed with libusb_free_interface_association_descriptors() + * after use. It's possible that a given configuration contains no IADs. In this + * case the iad_array is still output, but will have 'length' field set to 0, and + * iad field set to NULL. + * \returns 0 on success + * \returns LIBUSB_ERROR_NOT_FOUND if the configuration does not exist + * \returns another LIBUSB_ERROR code on error + * \see libusb_get_active_interface_association_descriptors() + */ +int API_EXPORTED libusb_get_interface_association_descriptors(libusb_device *dev, + uint8_t config_index, struct libusb_interface_association_descriptor_array **iad_array) +{ + union usbi_config_desc_buf _config; + uint16_t config_len; + uint8_t *buf; + int r; + + if (!iad_array) + return LIBUSB_ERROR_INVALID_PARAM; + + usbi_dbg(DEVICE_CTX(dev), "IADs for config index %u", config_index); + if (config_index >= dev->device_descriptor.bNumConfigurations) + return LIBUSB_ERROR_NOT_FOUND; + + r = get_config_descriptor(dev, config_index, _config.buf, sizeof(_config.buf)); + if (r < 0) + return r; + + config_len = libusb_le16_to_cpu(_config.desc.wTotalLength); + buf = malloc(config_len); + if (!buf) + return LIBUSB_ERROR_NO_MEM; + + r = get_config_descriptor(dev, config_index, buf, config_len); + if (r >= 0) + r = raw_desc_to_iad_array(DEVICE_CTX(dev), buf, r, iad_array); + + free(buf); + return r; +} + +/** \ingroup libusb_desc + * Get an array of interface association descriptors (IAD) for the currently + * active configuration. + * This is a non-blocking function which does not involve any requests being + * sent to the device. + * + * \param dev a device + * \param iad_array output location for the array of IADs. Only valid if 0 was + * returned. Must be freed with libusb_free_interface_association_descriptors() + * after use. It's possible that a given configuration contains no IADs. In this + * case the iad_array is still output, but will have 'length' field set to 0, and + * iad field set to NULL. + * \returns 0 on success + * \returns LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state + * \returns another LIBUSB_ERROR code on error + * \see libusb_get_interface_association_descriptors + */ +int API_EXPORTED libusb_get_active_interface_association_descriptors(libusb_device *dev, + struct libusb_interface_association_descriptor_array **iad_array) +{ + union usbi_config_desc_buf _config; + uint16_t config_len; + uint8_t *buf; + int r; + + if (!iad_array) + return LIBUSB_ERROR_INVALID_PARAM; + + r = get_active_config_descriptor(dev, _config.buf, sizeof(_config.buf)); + if (r < 0) + return r; + + config_len = libusb_le16_to_cpu(_config.desc.wTotalLength); + buf = malloc(config_len); + if (!buf) + return LIBUSB_ERROR_NO_MEM; + + r = get_active_config_descriptor(dev, buf, config_len); + if (r >= 0) + r = raw_desc_to_iad_array(DEVICE_CTX(dev), buf, r, iad_array); + free(buf); + return r; +} + +/** \ingroup libusb_desc + * Free an array of interface association descriptors (IADs) obtained from + * libusb_get_interface_association_descriptors() or + * libusb_get_active_interface_association_descriptors(). + * It is safe to call this function with a NULL iad_array parameter, in which + * case the function simply returns. + * + * \param iad_array the IAD array to free + */ +void API_EXPORTED libusb_free_interface_association_descriptors( + struct libusb_interface_association_descriptor_array *iad_array) +{ + if (!iad_array) + return; + + if (iad_array->iad) + free((void*)iad_array->iad); + free(iad_array); +} |