Merge "usblib: usb_device_get_string decoding fixes." (499d82e5) · Commits · e / os / android_system_core

libusbhost/include/usbhost/usbhost.h

+18 −0

Original line number	Diff line number	Diff line
		@@ -139,9 +139,27 @@ uint16_t usb_device_get_product_id(struct usb_device *device);

		const struct usb_device_descriptor* usb_device_get_device_descriptor(struct usb_device *device);

		/* Returns a USB descriptor string for the given string ID.
		* Return value: < 0 on error. 0 on success.
		* The string is returned in ucs2_out in USB-native UCS-2 encoding.
		*
		* parameters:
		* id - the string descriptor index.
		* timeout - in milliseconds (see Documentation/driver-api/usb/usb.rst)
		* ucs2_out - Must point to null on call.
		* Will be filled in with a buffer on success.
		* If this is non-null on return, it must be free()d.
		* response_size - size, in bytes, of ucs-2 string in ucs2_out.
		* The size isn't guaranteed to include null termination.
		* Call free() to free the result when you are done with it.
		*/
		int usb_device_get_string_ucs2(struct usb_device* device, int id, int timeout, void** ucs2_out,
		size_t* response_size);

		/* Returns a USB descriptor string for the given string ID.
		* Used to implement usb_device_get_manufacturer_name,
		* usb_device_get_product_name and usb_device_get_serial.
		* Returns ascii - non ascii characters will be replaced with '?'.
		* Call free() to free the result when you are done with it.
		*/
		char* usb_device_get_string(struct usb_device *device, int id, int timeout);

libusbhost/usbhost.c

+65 −23

Original line number	Diff line number	Diff line
		@@ -464,17 +464,30 @@ const struct usb_device_descriptor* usb_device_get_device_descriptor(struct usb_
		return (struct usb_device_descriptor*)device->desc;
		}

		char* usb_device_get_string(struct usb_device *device, int id, int timeout)
		{
		char string[256];
		__u16 buffer[MAX_STRING_DESCRIPTOR_LENGTH / sizeof(__u16)];
		/* Returns a USB descriptor string for the given string ID.
		* Return value: < 0 on error. 0 on success.
		* The string is returned in ucs2_out in USB-native UCS-2 encoding.
		*
		* parameters:
		* id - the string descriptor index.
		* timeout - in milliseconds (see Documentation/driver-api/usb/usb.rst)
		* ucs2_out - Must point to null on call.
		* Will be filled in with a buffer on success.
		* If this is non-null on return, it must be free()d.
		* response_size - size, in bytes, of ucs-2 string in ucs2_out.
		* The size isn't guaranteed to include null termination.
		* Call free() to free the result when you are done with it.
		*/
		int usb_device_get_string_ucs2(struct usb_device* device, int id, int timeout, void** ucs2_out,
		size_t* response_size) {
		__u16 languages[MAX_STRING_DESCRIPTOR_LENGTH / sizeof(__u16)];
		int i, result;
		char response[MAX_STRING_DESCRIPTOR_LENGTH];
		int result;
		int languageCount = 0;

		if (id == 0) return NULL;
		if (id == 0) return -1;
		if (*ucs2_out != NULL) return -1;

		string[0] = 0;
		memset(languages, 0, sizeof(languages));

		// read list of supported languages
		@@ -485,25 +498,54 @@ char* usb_device_get_string(struct usb_device *device, int id, int timeout)
		if (result > 0)
		languageCount = (result - 2) / 2;

		for (i = 1; i <= languageCount; i++) {
		memset(buffer, 0, sizeof(buffer));
		for (int i = 1; i <= languageCount; i++) {
		memset(response, 0, sizeof(response));

		result = usb_device_control_transfer(device,
		USB_DIR_IN\|USB_TYPE_STANDARD\|USB_RECIP_DEVICE, USB_REQ_GET_DESCRIPTOR,
		(USB_DT_STRING << 8) \| id, languages[i], buffer, sizeof(buffer),
		timeout);
		if (result > 0) {
		int i;
		// skip first word, and copy the rest to the string, changing shorts to bytes.
		result /= 2;
		for (i = 1; i < result; i++)
		string[i - 1] = buffer[i];
		string[i - 1] = 0;
		return strdup(string);
		result = usb_device_control_transfer(
		device, USB_DIR_IN \| USB_TYPE_STANDARD \| USB_RECIP_DEVICE, USB_REQ_GET_DESCRIPTOR,
		(USB_DT_STRING << 8) \| id, languages[i], response, sizeof(response), timeout);
		if (result >= 2) { // string contents begin at offset 2.
		int descriptor_len = result - 2;
		char* out = malloc(descriptor_len + 3);
		if (out == NULL) {
		return -1;
		}
		memcpy(out, response + 2, descriptor_len);
		// trail with three additional NULLs, so that there's guaranteed
		// to be a UCS-2 NULL character beyond whatever USB returned.
		// The returned string length is still just what USB returned.
		memset(out + descriptor_len, '\0', 3);
		ucs2_out = (void)out;
		*response_size = descriptor_len;
		return 0;
		}
		}
		return -1;
		}

		/* Warning: previously this blindly returned the lower 8 bits of
		* every UCS-2 character in a USB descriptor. Now it will replace
		* values > 127 with ascii '?'.
		*/
		char* usb_device_get_string(struct usb_device* device, int id, int timeout) {
		char* ascii_string = NULL;
		size_t raw_string_len = 0;
		size_t i;
		if (usb_device_get_string_ucs2(device, id, timeout, (void**)&ascii_string, &raw_string_len) < 0)
		return NULL;
		if (ascii_string == NULL) return NULL;
		for (i = 0; i < raw_string_len / 2; ++i) {
		// wire format for USB is always little-endian.
		char lower = ascii_string[2 * i];
		char upper = ascii_string[2 * i + 1];
		if (upper \|\| (lower & 0x80)) {
		ascii_string[i] = '?';
		} else {
		ascii_string[i] = lower;
		}
		}
		ascii_string[i] = '\0';
		return ascii_string;
		}

		char* usb_device_get_manufacturer_name(struct usb_device *device, int timeout)