255 lines
		
	
	
		
			7.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			255 lines
		
	
	
		
			7.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 *   fs/cifs/cifs_unicode.c
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 *
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 *   Copyright (c) International Business Machines  Corp., 2000,2009
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 *   Modified by Steve French (sfrench@us.ibm.com)
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 *
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 *   This program is free software;  you can redistribute it and/or modify
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 *   it under the terms of the GNU General Public License as published by
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 *   the Free Software Foundation; either version 2 of the License, or
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 *   (at your option) any later version.
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 *
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 *   This program is distributed in the hope that it will be useful,
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 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
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 *   the GNU General Public License for more details.
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 *
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 *   You should have received a copy of the GNU General Public License
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 *   along with this program;  if not, write to the Free Software
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 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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 */
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#include <linux/fs.h>
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#include "cifs_unicode.h"
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#include "cifs_uniupr.h"
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#include "cifspdu.h"
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#include "cifsglob.h"
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#include "cifs_debug.h"
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/*
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 * cifs_ucs2_bytes - how long will a string be after conversion?
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 * @ucs - pointer to input string
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 * @maxbytes - don't go past this many bytes of input string
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 * @codepage - destination codepage
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 *
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 * Walk a ucs2le string and return the number of bytes that the string will
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 * be after being converted to the given charset, not including any null
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 * termination required. Don't walk past maxbytes in the source buffer.
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 */
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int
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cifs_ucs2_bytes(const __le16 *from, int maxbytes,
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		const struct nls_table *codepage)
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{
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	int i;
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	int charlen, outlen = 0;
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	int maxwords = maxbytes / 2;
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	char tmp[NLS_MAX_CHARSET_SIZE];
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	for (i = 0; i < maxwords && from[i]; i++) {
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		charlen = codepage->uni2char(le16_to_cpu(from[i]), tmp,
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					     NLS_MAX_CHARSET_SIZE);
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		if (charlen > 0)
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			outlen += charlen;
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		else
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			outlen++;
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	}
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	return outlen;
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}
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/*
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 * cifs_mapchar - convert a little-endian char to proper char in codepage
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 * @target - where converted character should be copied
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 * @src_char - 2 byte little-endian source character
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 * @cp - codepage to which character should be converted
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 * @mapchar - should character be mapped according to mapchars mount option?
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 *
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 * This function handles the conversion of a single character. It is the
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 * responsibility of the caller to ensure that the target buffer is large
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 * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
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 */
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static int
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cifs_mapchar(char *target, const __le16 src_char, const struct nls_table *cp,
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	     bool mapchar)
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{
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	int len = 1;
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	if (!mapchar)
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		goto cp_convert;
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	/*
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	 * BB: Cannot handle remapping UNI_SLASH until all the calls to
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	 *     build_path_from_dentry are modified, as they use slash as
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	 *     separator.
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	 */
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	switch (le16_to_cpu(src_char)) {
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	case UNI_COLON:
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		*target = ':';
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		break;
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	case UNI_ASTERIK:
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		*target = '*';
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		break;
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	case UNI_QUESTION:
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		*target = '?';
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		break;
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	case UNI_PIPE:
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		*target = '|';
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		break;
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	case UNI_GRTRTHAN:
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		*target = '>';
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		break;
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	case UNI_LESSTHAN:
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		*target = '<';
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		break;
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	default:
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		goto cp_convert;
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	}
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out:
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	return len;
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cp_convert:
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	len = cp->uni2char(le16_to_cpu(src_char), target,
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			   NLS_MAX_CHARSET_SIZE);
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	if (len <= 0) {
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		*target = '?';
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		len = 1;
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	}
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	goto out;
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}
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/*
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 * cifs_from_ucs2 - convert utf16le string to local charset
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 * @to - destination buffer
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 * @from - source buffer
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 * @tolen - destination buffer size (in bytes)
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 * @fromlen - source buffer size (in bytes)
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 * @codepage - codepage to which characters should be converted
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 * @mapchar - should characters be remapped according to the mapchars option?
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 *
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 * Convert a little-endian ucs2le string (as sent by the server) to a string
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 * in the provided codepage. The tolen and fromlen parameters are to ensure
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 * that the code doesn't walk off of the end of the buffer (which is always
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 * a danger if the alignment of the source buffer is off). The destination
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 * string is always properly null terminated and fits in the destination
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 * buffer. Returns the length of the destination string in bytes (including
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 * null terminator).
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 *
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 * Note that some windows versions actually send multiword UTF-16 characters
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 * instead of straight UCS-2. The linux nls routines however aren't able to
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 * deal with those characters properly. In the event that we get some of
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 * those characters, they won't be translated properly.
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 */
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int
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cifs_from_ucs2(char *to, const __le16 *from, int tolen, int fromlen,
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		 const struct nls_table *codepage, bool mapchar)
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{
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	int i, charlen, safelen;
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	int outlen = 0;
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	int nullsize = nls_nullsize(codepage);
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	int fromwords = fromlen / 2;
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	char tmp[NLS_MAX_CHARSET_SIZE];
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	/*
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	 * because the chars can be of varying widths, we need to take care
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	 * not to overflow the destination buffer when we get close to the
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	 * end of it. Until we get to this offset, we don't need to check
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	 * for overflow however.
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	 */
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	safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
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	for (i = 0; i < fromwords && from[i]; i++) {
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		/*
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		 * check to see if converting this character might make the
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		 * conversion bleed into the null terminator
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		 */
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		if (outlen >= safelen) {
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			charlen = cifs_mapchar(tmp, from[i], codepage, mapchar);
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			if ((outlen + charlen) > (tolen - nullsize))
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				break;
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		}
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		/* put converted char into 'to' buffer */
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		charlen = cifs_mapchar(&to[outlen], from[i], codepage, mapchar);
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		outlen += charlen;
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	}
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	/* properly null-terminate string */
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	for (i = 0; i < nullsize; i++)
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		to[outlen++] = 0;
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	return outlen;
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}
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/*
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 * NAME:	cifs_strtoUCS()
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 *
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 * FUNCTION:	Convert character string to unicode string
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 *
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 */
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int
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cifs_strtoUCS(__le16 *to, const char *from, int len,
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	      const struct nls_table *codepage)
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{
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	int charlen;
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	int i;
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	wchar_t *wchar_to = (wchar_t *)to; /* needed to quiet sparse */
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	for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
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		/* works for 2.4.0 kernel or later */
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		charlen = codepage->char2uni(from, len, &wchar_to[i]);
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		if (charlen < 1) {
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			cERROR(1,
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			       ("strtoUCS: char2uni of %d returned %d",
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				(int)*from, charlen));
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			/* A question mark */
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			to[i] = cpu_to_le16(0x003f);
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			charlen = 1;
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		} else
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			to[i] = cpu_to_le16(wchar_to[i]);
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	}
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	to[i] = 0;
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	return i;
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}
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/*
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 * cifs_strndup_from_ucs - copy a string from wire format to the local codepage
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 * @src - source string
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 * @maxlen - don't walk past this many bytes in the source string
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 * @is_unicode - is this a unicode string?
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 * @codepage - destination codepage
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 *
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 * Take a string given by the server, convert it to the local codepage and
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 * put it in a new buffer. Returns a pointer to the new string or NULL on
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 * error.
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 */
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char *
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cifs_strndup_from_ucs(const char *src, const int maxlen, const bool is_unicode,
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	     const struct nls_table *codepage)
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{
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	int len;
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	char *dst;
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	if (is_unicode) {
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		len = cifs_ucs2_bytes((__le16 *) src, maxlen, codepage);
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		len += nls_nullsize(codepage);
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		dst = kmalloc(len, GFP_KERNEL);
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		if (!dst)
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			return NULL;
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		cifs_from_ucs2(dst, (__le16 *) src, len, maxlen, codepage,
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			       false);
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	} else {
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		len = strnlen(src, maxlen);
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		len++;
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		dst = kmalloc(len, GFP_KERNEL);
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		if (!dst)
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			return NULL;
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		strlcpy(dst, src, len);
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	}
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	return dst;
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}
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