- 根目录:
- fs
- cifs
- cifs_unicode.c
/*
* fs/cifs/cifs_unicode.c
*
* Copyright (c) International Business Machines Corp., 2000,2009
* Modified by Steve French (sfrench@us.ibm.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include "cifs_unicode.h"
#include "cifs_uniupr.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifs_debug.h"
/*
* cifs_utf16_bytes - how long will a string be after conversion?
* @utf16 - pointer to input string
* @maxbytes - don't go past this many bytes of input string
* @codepage - destination codepage
*
* Walk a utf16le string and return the number of bytes that the string will
* be after being converted to the given charset, not including any null
* termination required. Don't walk past maxbytes in the source buffer.
*/
int
cifs_utf16_bytes(const __le16 *from, int maxbytes,
const struct nls_table *codepage)
{
int i;
int charlen, outlen = 0;
int maxwords = maxbytes / 2;
char tmp[NLS_MAX_CHARSET_SIZE];
__u16 ftmp;
for (i = 0; i < maxwords; i++) {
ftmp = get_unaligned_le16(&from[i]);
if (ftmp == 0)
break;
charlen = codepage->uni2char(ftmp, tmp, NLS_MAX_CHARSET_SIZE);
if (charlen > 0)
outlen += charlen;
else
outlen++;
}
return outlen;
}
/*
* cifs_mapchar - convert a host-endian char to proper char in codepage
* @target - where converted character should be copied
* @src_char - 2 byte host-endian source character
* @cp - codepage to which character should be converted
* @mapchar - should character be mapped according to mapchars mount option?
*
* This function handles the conversion of a single character. It is the
* responsibility of the caller to ensure that the target buffer is large
* enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
*/
static int
cifs_mapchar(char *target, const __u16 src_char, const struct nls_table *cp,
bool mapchar)
{
int len = 1;
if (!mapchar)
goto cp_convert;
/*
* BB: Cannot handle remapping UNI_SLASH until all the calls to
* build_path_from_dentry are modified, as they use slash as
* separator.
*/
switch (src_char) {
case UNI_COLON:
*target = ':';
break;
case UNI_ASTERISK:
*target = '*';
break;
case UNI_QUESTION:
*target = '?';
break;
case UNI_PIPE:
*target = '|';
break;
case UNI_GRTRTHAN:
*target = '>';
break;
case UNI_LESSTHAN:
*target = '<';
break;
default:
goto cp_convert;
}
out:
return len;
cp_convert:
len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
if (len <= 0) {
*target = '?';
len = 1;
}
goto out;
}
/*
* cifs_from_utf16 - convert utf16le string to local charset
* @to - destination buffer
* @from - source buffer
* @tolen - destination buffer size (in bytes)
* @fromlen - source buffer size (in bytes)
* @codepage - codepage to which characters should be converted
* @mapchar - should characters be remapped according to the mapchars option?
*
* Convert a little-endian utf16le string (as sent by the server) to a string
* in the provided codepage. The tolen and fromlen parameters are to ensure
* that the code doesn't walk off of the end of the buffer (which is always
* a danger if the alignment of the source buffer is off). The destination
* string is always properly null terminated and fits in the destination
* buffer. Returns the length of the destination string in bytes (including
* null terminator).
*
* Note that some windows versions actually send multiword UTF-16 characters
* instead of straight UTF16-2. The linux nls routines however aren't able to
* deal with those characters properly. In the event that we get some of
* those characters, they won't be translated properly.
*/
int
cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
const struct nls_table *codepage, bool mapchar)
{
int i, charlen, safelen;
int outlen = 0;
int nullsize = nls_nullsize(codepage);
int fromwords = fromlen / 2;
char tmp[NLS_MAX_CHARSET_SIZE];
__u16 ftmp;
/*
* because the chars can be of varying widths, we need to take care
* not to overflow the destination buffer when we get close to the
* end of it. Until we get to this offset, we don't need to check
* for overflow however.
*/
safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
for (i = 0; i < fromwords; i++) {
ftmp = get_unaligned_le16(&from[i]);
if (ftmp == 0)
break;
/*
* check to see if converting this character might make the
* conversion bleed into the null terminator
*/
if (outlen >= safelen) {
charlen = cifs_mapchar(tmp, ftmp, codepage, mapchar);
if ((outlen + charlen) > (tolen - nullsize))
break;
}
/* put converted char into 'to' buffer */
charlen = cifs_mapchar(&to[outlen], ftmp, codepage, mapchar);
outlen += charlen;
}
/* properly null-terminate string */
for (i = 0; i < nullsize; i++)
to[outlen++] = 0;
return outlen;
}
/*
* NAME: cifs_strtoUTF16()
*
* FUNCTION: Convert character string to unicode string
*
*/
int
cifs_strtoUTF16(__le16 *to, const char *from, int len,
const struct nls_table *codepage)
{
int charlen;
int i;
wchar_t wchar_to; /* needed to quiet sparse */
/* special case for utf8 to handle no plane0 chars */
if (!strcmp(codepage->charset, "utf8")) {
/*
* convert utf8 -> utf16, we assume we have enough space
* as caller should have assumed conversion does not overflow
* in destination len is length in wchar_t units (16bits)
*/
i = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
(wchar_t *) to, len);
/* if success terminate and exit */
if (i >= 0)
goto success;
/*
* if fails fall back to UCS encoding as this
* function should not return negative values
* currently can fail only if source contains
* invalid encoded characters
*/
}
for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
charlen = codepage->char2uni(from, len, &wchar_to);
if (charlen < 1) {
cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
*from, charlen);
/* A question mark */
wchar_to = 0x003f;
charlen = 1;
}
put_unaligned_le16(wchar_to, &to[i]);
}
success:
put_unaligned_le16(0, &to[i]);
return i;
}
/*
* cifs_strndup_from_utf16 - copy a string from wire format to the local
* codepage
* @src - source string
* @maxlen - don't walk past this many bytes in the source string
* @is_unicode - is this a unicode string?
* @codepage - destination codepage
*
* Take a string given by the server, convert it to the local codepage and
* put it in a new buffer. Returns a pointer to the new string or NULL on
* error.
*/
char *
cifs_strndup_from_utf16(const char *src, const int maxlen,
const bool is_unicode, const struct nls_table *codepage)
{
int len;
char *dst;
if (is_unicode) {
len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
len += nls_nullsize(codepage);
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return NULL;
cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
false);
} else {
len = strnlen(src, maxlen);
len++;
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return NULL;
strlcpy(dst, src, len);
}
return dst;
}
/*
* Convert 16 bit Unicode pathname to wire format from string in current code
* page. Conversion may involve remapping up the six characters that are
* only legal in POSIX-like OS (if they are present in the string). Path
* names are little endian 16 bit Unicode on the wire
*/
int
cifsConvertToUTF16(__le16 *target, const char *source, int srclen,
const struct nls_table *cp, int mapChars)
{
int i, j, charlen;
char src_char;
__le16 dst_char;
wchar_t tmp;
if (!mapChars)
return cifs_strtoUTF16(target, source, PATH_MAX, cp);
for (i = 0, j = 0; i < srclen; j++) {
src_char = source[i];
charlen = 1;
switch (src_char) {
case 0:
put_unaligned(0, &target[j]);
goto ctoUTF16_out;
case ':':
dst_char = cpu_to_le16(UNI_COLON);
break;
case '*':
dst_char = cpu_to_le16(UNI_ASTERISK);
break;
case '?':
dst_char = cpu_to_le16(UNI_QUESTION);
break;
case '<':
dst_char = cpu_to_le16(UNI_LESSTHAN);
break;
case '>':
dst_char = cpu_to_le16(UNI_GRTRTHAN);
break;
case '|':
dst_char = cpu_to_le16(UNI_PIPE);
break;
/*
* FIXME: We can not handle remapping backslash (UNI_SLASH)
* until all the calls to build_path_from_dentry are modified,
* as they use backslash as separator.
*/
default:
charlen = cp->char2uni(source + i, srclen - i, &tmp);
dst_char = cpu_to_le16(tmp);
/*
* if no match, use question mark, which at least in
* some cases serves as wild card
*/
if (charlen < 1) {
dst_char = cpu_to_le16(0x003f);
charlen = 1;
}
}
/*
* character may take more than one byte in the source string,
* but will take exactly two bytes in the target string
*/
i += charlen;
put_unaligned(dst_char, &target[j]);
}
ctoUTF16_out:
return j;
}
#ifdef CONFIG_CIFS_SMB2
/*
* cifs_local_to_utf16_bytes - how long will a string be after conversion?
* @from - pointer to input string
* @maxbytes - don't go past this many bytes of input string
* @codepage - source codepage
*
* Walk a string and return the number of bytes that the string will
* be after being converted to the given charset, not including any null
* termination required. Don't walk past maxbytes in the source buffer.
*/
static int
cifs_local_to_utf16_bytes(const char *from, int len,
const struct nls_table *codepage)
{
int charlen;
int i;
wchar_t wchar_to;
for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
charlen = codepage->char2uni(from, len, &wchar_to);
/* Failed conversion defaults to a question mark */
if (charlen < 1)
charlen = 1;
}
return 2 * i; /* UTF16 characters are two bytes */
}
/*
* cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
* @src - source string
* @maxlen - don't walk past this many bytes in the source string
* @utf16_len - the length of the allocated string in bytes (including null)
* @cp - source codepage
* @remap - map special chars
*
* Take a string convert it from the local codepage to UTF16 and
* put it in a new buffer. Returns a pointer to the new string or NULL on
* error.
*/
__le16 *
cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
const struct nls_table *cp, int remap)
{
int len;
__le16 *dst;
len = cifs_local_to_utf16_bytes(src, maxlen, cp);
len += 2; /* NULL */
dst = kmalloc(len, GFP_KERNEL);
if (!dst) {
*utf16_len = 0;
return NULL;
}
cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
*utf16_len = len;
return dst;
}
#endif /* CONFIG_CIFS_SMB2 */