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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * fs/cifs/cifs_unicode.c
3 *
Steve Frenchd185cda2009-04-30 17:45:10 +00004 * Copyright (c) International Business Machines Corp., 2000,2009
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 * Modified by Steve French (sfrench@us.ibm.com)
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
Steve French221601c2007-06-05 20:35:06 +00009 * the Free Software Foundation; either version 2 of the License, or
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 * (at your option) any later version.
Steve French221601c2007-06-05 20:35:06 +000011 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 * the GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
Steve French221601c2007-06-05 20:35:06 +000018 * along with this program; if not, write to the Free Software
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21#include <linux/fs.h>
22#include "cifs_unicode.h"
23#include "cifs_uniupr.h"
24#include "cifspdu.h"
Steve French39798772006-05-31 22:40:51 +000025#include "cifsglob.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include "cifs_debug.h"
27
28/*
Jeff Layton69f801f2009-04-30 06:46:32 -040029 * cifs_ucs2_bytes - how long will a string be after conversion?
30 * @ucs - pointer to input string
31 * @maxbytes - don't go past this many bytes of input string
32 * @codepage - destination codepage
33 *
34 * Walk a ucs2le string and return the number of bytes that the string will
35 * be after being converted to the given charset, not including any null
36 * termination required. Don't walk past maxbytes in the source buffer.
37 */
38int
39cifs_ucs2_bytes(const __le16 *from, int maxbytes,
40 const struct nls_table *codepage)
41{
42 int i;
43 int charlen, outlen = 0;
44 int maxwords = maxbytes / 2;
45 char tmp[NLS_MAX_CHARSET_SIZE];
46
47 for (i = 0; from[i] && i < maxwords; i++) {
48 charlen = codepage->uni2char(le16_to_cpu(from[i]), tmp,
49 NLS_MAX_CHARSET_SIZE);
50 if (charlen > 0)
51 outlen += charlen;
52 else
53 outlen++;
54 }
55
56 return outlen;
57}
58
59/*
Jeff Layton7fabf0c2009-04-30 06:46:15 -040060 * cifs_mapchar - convert a little-endian char to proper char in codepage
61 * @target - where converted character should be copied
62 * @src_char - 2 byte little-endian source character
63 * @cp - codepage to which character should be converted
64 * @mapchar - should character be mapped according to mapchars mount option?
65 *
66 * This function handles the conversion of a single character. It is the
67 * responsibility of the caller to ensure that the target buffer is large
68 * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
69 */
70static int
71cifs_mapchar(char *target, const __le16 src_char, const struct nls_table *cp,
72 bool mapchar)
73{
74 int len = 1;
75
76 if (!mapchar)
77 goto cp_convert;
78
79 /*
80 * BB: Cannot handle remapping UNI_SLASH until all the calls to
81 * build_path_from_dentry are modified, as they use slash as
82 * separator.
83 */
84 switch (le16_to_cpu(src_char)) {
85 case UNI_COLON:
86 *target = ':';
87 break;
88 case UNI_ASTERIK:
89 *target = '*';
90 break;
91 case UNI_QUESTION:
92 *target = '?';
93 break;
94 case UNI_PIPE:
95 *target = '|';
96 break;
97 case UNI_GRTRTHAN:
98 *target = '>';
99 break;
100 case UNI_LESSTHAN:
101 *target = '<';
102 break;
103 default:
104 goto cp_convert;
105 }
106
107out:
108 return len;
109
110cp_convert:
111 len = cp->uni2char(le16_to_cpu(src_char), target,
112 NLS_MAX_CHARSET_SIZE);
113 if (len <= 0) {
114 *target = '?';
115 len = 1;
116 }
117 goto out;
118}
119
120/*
121 * cifs_from_ucs2 - convert utf16le string to local charset
122 * @to - destination buffer
123 * @from - source buffer
124 * @tolen - destination buffer size (in bytes)
125 * @fromlen - source buffer size (in bytes)
126 * @codepage - codepage to which characters should be converted
127 * @mapchar - should characters be remapped according to the mapchars option?
128 *
129 * Convert a little-endian ucs2le string (as sent by the server) to a string
130 * in the provided codepage. The tolen and fromlen parameters are to ensure
131 * that the code doesn't walk off of the end of the buffer (which is always
132 * a danger if the alignment of the source buffer is off). The destination
133 * string is always properly null terminated and fits in the destination
134 * buffer. Returns the length of the destination string in bytes (including
135 * null terminator).
136 *
137 * Note that some windows versions actually send multiword UTF-16 characters
138 * instead of straight UCS-2. The linux nls routines however aren't able to
139 * deal with those characters properly. In the event that we get some of
140 * those characters, they won't be translated properly.
141 */
142int
143cifs_from_ucs2(char *to, const __le16 *from, int tolen, int fromlen,
144 const struct nls_table *codepage, bool mapchar)
145{
146 int i, charlen, safelen;
147 int outlen = 0;
148 int nullsize = nls_nullsize(codepage);
149 int fromwords = fromlen / 2;
150 char tmp[NLS_MAX_CHARSET_SIZE];
151
152 /*
153 * because the chars can be of varying widths, we need to take care
154 * not to overflow the destination buffer when we get close to the
155 * end of it. Until we get to this offset, we don't need to check
156 * for overflow however.
157 */
158 safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
159
160 for (i = 0; i < fromwords && from[i]; i++) {
161 /*
162 * check to see if converting this character might make the
163 * conversion bleed into the null terminator
164 */
165 if (outlen >= safelen) {
166 charlen = cifs_mapchar(tmp, from[i], codepage, mapchar);
167 if ((outlen + charlen) > (tolen - nullsize))
168 break;
169 }
170
171 /* put converted char into 'to' buffer */
172 charlen = cifs_mapchar(&to[outlen], from[i], codepage, mapchar);
173 outlen += charlen;
174 }
175
176 /* properly null-terminate string */
177 for (i = 0; i < nullsize; i++)
178 to[outlen++] = 0;
179
180 return outlen;
181}
182
183/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 * NAME: cifs_strtoUCS()
185 *
186 * FUNCTION: Convert character string to unicode string
187 *
188 */
189int
Steve Frenchad7a2922008-02-07 23:25:02 +0000190cifs_strtoUCS(__le16 *to, const char *from, int len,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 const struct nls_table *codepage)
192{
193 int charlen;
194 int i;
Steve French50c2f752007-07-13 00:33:32 +0000195 wchar_t *wchar_to = (wchar_t *)to; /* needed to quiet sparse */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
197 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
198
199 /* works for 2.4.0 kernel or later */
Steve Frenche89dc922005-11-11 15:18:19 -0800200 charlen = codepage->char2uni(from, len, &wchar_to[i]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 if (charlen < 1) {
202 cERROR(1,
Steve French3a9f4622007-04-04 17:10:24 +0000203 ("strtoUCS: char2uni of %d returned %d",
204 (int)*from, charlen));
Steve French69114082005-11-10 19:28:44 -0800205 /* A question mark */
Steve Frenche89dc922005-11-11 15:18:19 -0800206 to[i] = cpu_to_le16(0x003f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 charlen = 1;
Steve French221601c2007-06-05 20:35:06 +0000208 } else
Steve Frenche89dc922005-11-11 15:18:19 -0800209 to[i] = cpu_to_le16(wchar_to[i]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
211 }
212
213 to[i] = 0;
214 return i;
215}
216
Jeff Layton066ce682009-04-30 07:16:14 -0400217/*
Steve Frenchd185cda2009-04-30 17:45:10 +0000218 * cifs_strndup_from_ucs - copy a string from wire format to the local codepage
Jeff Layton066ce682009-04-30 07:16:14 -0400219 * @src - source string
220 * @maxlen - don't walk past this many bytes in the source string
221 * @is_unicode - is this a unicode string?
222 * @codepage - destination codepage
223 *
224 * Take a string given by the server, convert it to the local codepage and
225 * put it in a new buffer. Returns a pointer to the new string or NULL on
226 * error.
227 */
228char *
Steve Frenchd185cda2009-04-30 17:45:10 +0000229cifs_strndup_from_ucs(const char *src, const int maxlen, const bool is_unicode,
Jeff Layton066ce682009-04-30 07:16:14 -0400230 const struct nls_table *codepage)
231{
232 int len;
233 char *dst;
234
235 if (is_unicode) {
236 len = cifs_ucs2_bytes((__le16 *) src, maxlen, codepage);
237 len += nls_nullsize(codepage);
238 dst = kmalloc(len, GFP_KERNEL);
239 if (!dst)
240 return NULL;
241 cifs_from_ucs2(dst, (__le16 *) src, len, maxlen, codepage,
242 false);
243 } else {
244 len = strnlen(src, maxlen);
245 len++;
246 dst = kmalloc(len, GFP_KERNEL);
247 if (!dst)
248 return NULL;
249 strlcpy(dst, src, len);
250 }
251
252 return dst;
253}
254