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Commit 86dc243c authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: remove homegrown UTF conversion routine for gadgets 



This patch (as1502) removes the UTF8-to-UTF16 conversion routine in
the USB gadget library and replaces it with a call to the equivalent
function in the NLS library.

The only downside worth noting is that the NLS library routine
requires the output buffer to be 16-bit aligned.  This is always true
in the gadget code, because the output buffer is always a
usb_request buffer being used to send a string descriptor.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 0720a06a

drivers/usb/gadget/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -15,6 +15,7 @@ 




menuconfig USB_GADGET

menuconfig USB_GADGET

	tristate "USB Gadget Support"

	tristate "USB Gadget Support"

	select NLS

	help

	help

	   USB is a master/slave protocol, organized with one master

	   USB is a master/slave protocol, organized with one master

	   host (such as a PC) controlling up to 127 peripheral devices.

	   host (such as a PC) controlling up to 127 peripheral devices.

drivers/usb/gadget/usbstring.c

+4 −69
Original line number Original line Diff line number Diff line
@@ -13,82 +13,17 @@ 
#include <linux/string.h>

#include <linux/string.h>

#include <linux/device.h>

#include <linux/device.h>

#include <linux/init.h>

#include <linux/init.h>

#include <linux/nls.h>





#include <linux/usb/ch9.h>

#include <linux/usb/ch9.h>

#include <linux/usb/gadget.h>

#include <linux/usb/gadget.h>





#include <asm/unaligned.h>





static int utf8_to_utf16le(const char *s, __le16 *cp, unsigned len)

{

	int	count = 0;

	u8	c;

	u16	uchar;



	/* this insists on correct encodings, though not minimal ones.

	 * BUT it currently rejects legit 4-byte UTF-8 code points,

	 * which need surrogate pairs.  (Unicode 3.1 can use them.)

	 */

	while (len != 0 && (c = (u8) *s++) != 0) {

		if (unlikely(c & 0x80)) {

			// 2-byte sequence:

			// 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx

			if ((c & 0xe0) == 0xc0) {

				uchar = (c & 0x1f) << 6;



				c = (u8) *s++;

				if ((c & 0xc0) != 0x80)

					goto fail;

				c &= 0x3f;

				uchar |= c;



			// 3-byte sequence (most CJKV characters):

			// zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx

			} else if ((c & 0xf0) == 0xe0) {

				uchar = (c & 0x0f) << 12;



				c = (u8) *s++;

				if ((c & 0xc0) != 0x80)

					goto fail;

				c &= 0x3f;

				uchar |= c << 6;



				c = (u8) *s++;

				if ((c & 0xc0) != 0x80)

					goto fail;

				c &= 0x3f;

				uchar |= c;



				/* no bogus surrogates */

				if (0xd800 <= uchar && uchar <= 0xdfff)

					goto fail;



			// 4-byte sequence (surrogate pairs, currently rare):

			// 11101110wwwwzzzzyy + 110111yyyyxxxxxx

			//     = 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx

			// (uuuuu = wwww + 1)

			// FIXME accept the surrogate code points (only)



			} else

				goto fail;

		} else

			uchar = c;

		put_unaligned_le16(uchar, cp++);

		count++;

		len--;

	}

	return count;

fail:

	return -1;

}







/**

/**

 * usb_gadget_get_string - fill out a string descriptor 

 * usb_gadget_get_string - fill out a string descriptor 

 * @table: of c strings encoded using UTF-8

 * @table: of c strings encoded using UTF-8

 * @id: string id, from low byte of wValue in get string descriptor

 * @id: string id, from low byte of wValue in get string descriptor

 * @buf: at least 256 bytes

 * @buf: at least 256 bytes, must be 16-bit aligned

 *

 *

 * Finds the UTF-8 string matching the ID, and converts it into a

 * Finds the UTF-8 string matching the ID, and converts it into a

 * string descriptor in utf16-le.

 * string descriptor in utf16-le.
@@ -125,8 +60,8 @@ usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf) 




	/* string descriptors have length, tag, then UTF16-LE text */

	/* string descriptors have length, tag, then UTF16-LE text */

	len = min ((size_t) 126, strlen (s->s));

	len = min ((size_t) 126, strlen (s->s));

	memset (buf + 2, 0, 2 * len);	/* zero all the bytes */

	len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,

	len = utf8_to_utf16le(s->s, (__le16 *)&buf[2], len);

			(wchar_t *) &buf[2], 126);

	if (len < 0)

	if (len < 0)

		return -EINVAL;

		return -EINVAL;

	buf [0] = (len + 1) * 2;

	buf [0] = (len + 1) * 2;