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Subject[ 139/184] NLS: improve UTF8 -> UTF16 string conversion routine
2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Alan Stern <stern@rowland.harvard.edu>

commit 0720a06a7518c9d0c0125bd5d1f3b6264c55c3dd upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
[bwh: Bakckported to 2.6.32: drop Hyper-V change]
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
fs/fat/namei_vfat.c | 3 ++-
fs/nls/nls_base.c | 43 +++++++++++++++++++++++++++++++++----------
include/linux/nls.h | 5 +++--
3 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 67b3df1..4251f35 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -499,7 +499,8 @@ xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
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)
diff --git a/fs/nls/nls_base.c b/fs/nls/nls_base.c
index 44a88a9..0eb059e 100644
--- a/fs/nls/nls_base.c
+++ b/fs/nls/nls_base.c
@@ -114,34 +114,57 @@ int utf32_to_utf8(unicode_t u, u8 *s, int maxlen)
}
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;
diff --git a/include/linux/nls.h b/include/linux/nls.h
index d47beef..5dc635f 100644
--- a/include/linux/nls.h
+++ b/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_default(void);

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);

--
1.7.12.2.21.g234cd45.dirty




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