lkml.org 
[lkml]   [2011]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] NLS: improve UTF8 -> UTF16 string conversion routine
The utf8s_to_utf16s conversion routine needs to be improved.  Unlike
its utf16s_to_utf8s sibling, it doesn't accept arguments specifying
the maximum length of the output buffer or the endianness of its
16-bit output.

This patch (as1501) adds the two missing arguments, and adjusts the
only two places in the kernel where the function is called. A
follow-on patch will add a third caller that does utilize the new
capabilities.

The two conversion routines are still annoyingly inconsistent in the
way they handle invalid byte combinations. But that's a subject for a
different patch.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Clemens Ladisch <clemens@ladisch.de>

---

drivers/hv/hv_kvp.c | 10 ++++++----
fs/fat/namei_vfat.c | 3 ++-
fs/nls/nls_base.c | 43 +++++++++++++++++++++++++++++++++----------
include/linux/nls.h | 5 +++--
4 files changed, 44 insertions(+), 17 deletions(-)

Index: usb-3.2/include/linux/nls.h
===================================================================
--- usb-3.2.orig/include/linux/nls.h
+++ usb-3.2/include/linux/nls.h
@@ -43,7 +43,7 @@ enum utf16_endian {
UTF16_BIG_ENDIAN
};

-/* nls.c */
+/* nls_base.c */
extern int register_nls(struct nls_table *);
extern int unregister_nls(struct nls_table *);
extern struct nls_table *load_nls(char *);
@@ -52,7 +52,8 @@ extern struct nls_table *load_nls_defaul

extern int utf8_to_utf32(const u8 *s, int len, unicode_t *pu);
extern int utf32_to_utf8(unicode_t u, u8 *s, int maxlen);
-extern int utf8s_to_utf16s(const u8 *s, int len, wchar_t *pwcs);
+extern int utf8s_to_utf16s(const u8 *s, int len,
+ enum utf16_endian endian, wchar_t *pwcs, int maxlen);
extern int utf16s_to_utf8s(const wchar_t *pwcs, int len,
enum utf16_endian endian, u8 *s, int maxlen);

Index: usb-3.2/fs/nls/nls_base.c
===================================================================
--- usb-3.2.orig/fs/nls/nls_base.c
+++ usb-3.2/fs/nls/nls_base.c
@@ -114,34 +114,57 @@ int utf32_to_utf8(unicode_t u, u8 *s, in
}
EXPORT_SYMBOL(utf32_to_utf8);

-int utf8s_to_utf16s(const u8 *s, int len, wchar_t *pwcs)
+static inline void put_utf16(wchar_t *s, unsigned c, enum utf16_endian endian)
+{
+ switch (endian) {
+ default:
+ *s = (wchar_t) c;
+ break;
+ case UTF16_LITTLE_ENDIAN:
+ *s = __cpu_to_le16(c);
+ break;
+ case UTF16_BIG_ENDIAN:
+ *s = __cpu_to_be16(c);
+ break;
+ }
+}
+
+int utf8s_to_utf16s(const u8 *s, int len, enum utf16_endian endian,
+ wchar_t *pwcs, int maxlen)
{
u16 *op;
int size;
unicode_t u;

op = pwcs;
- while (*s && len > 0) {
+ while (len > 0 && maxlen > 0 && *s) {
if (*s & 0x80) {
size = utf8_to_utf32(s, len, &u);
if (size < 0)
return -EINVAL;
+ s += size;
+ len -= size;

if (u >= PLANE_SIZE) {
+ if (maxlen < 2)
+ break;
u -= PLANE_SIZE;
- *op++ = (wchar_t) (SURROGATE_PAIR |
- ((u >> 10) & SURROGATE_BITS));
- *op++ = (wchar_t) (SURROGATE_PAIR |
+ put_utf16(op++, SURROGATE_PAIR |
+ ((u >> 10) & SURROGATE_BITS),
+ endian);
+ put_utf16(op++, SURROGATE_PAIR |
SURROGATE_LOW |
- (u & SURROGATE_BITS));
+ (u & SURROGATE_BITS),
+ endian);
+ maxlen -= 2;
} else {
- *op++ = (wchar_t) u;
+ put_utf16(op++, u, endian);
+ maxlen--;
}
- s += size;
- len -= size;
} else {
- *op++ = *s++;
+ put_utf16(op++, *s++, endian);
len--;
+ maxlen--;
}
}
return op - pwcs;
Index: usb-3.2/fs/fat/namei_vfat.c
===================================================================
--- usb-3.2.orig/fs/fat/namei_vfat.c
+++ usb-3.2/fs/fat/namei_vfat.c
@@ -512,7 +512,8 @@ xlate_to_uni(const unsigned char *name,
int charlen;

if (utf8) {
- *outlen = utf8s_to_utf16s(name, len, (wchar_t *)outname);
+ *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN,
+ (wchar_t *) outname, FAT_LFN_LEN + 2);
if (*outlen < 0)
return *outlen;
else if (*outlen > FAT_LFN_LEN)
Index: usb-3.2/drivers/hv/hv_kvp.c
===================================================================
--- usb-3.2.orig/drivers/hv/hv_kvp.c
+++ usb-3.2/drivers/hv/hv_kvp.c
@@ -212,11 +212,13 @@ kvp_respond_to_host(char *key, char *val
* The windows host expects the key/value pair to be encoded
* in utf16.
*/
- keylen = utf8s_to_utf16s(key_name, strlen(key_name),
- (wchar_t *)kvp_data->data.key);
+ keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
+ (wchar_t *) kvp_data->data.key,
+ HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2);
kvp_data->data.key_size = 2*(keylen + 1); /* utf16 encoding */
- valuelen = utf8s_to_utf16s(value, strlen(value),
- (wchar_t *)kvp_data->data.value);
+ valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
+ (wchar_t *) kvp_data->data.value,
+ HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2);
kvp_data->data.value_size = 2*(valuelen + 1); /* utf16 encoding */

kvp_data->data.value_type = REG_SZ; /* all our values are strings */


\
 
 \ /
  Last update: 2011-11-17 22:45    [W:2.554 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site