NLS: update handling of Unicode

This patch (as1239) updates the kernel's treatment of Unicode.  The
character-set conversion routines are well behind the current state of
the Unicode specification: They don't recognize the existence of code
points beyond plane 0 or of surrogate pairs in the UTF-16 encoding.

The old wchar_t 16-bit type is retained because it's still used in
lots of places.  This shouldn't cause any new problems; if a
conversion now results in an invalid 16-bit code then before it must
have yielded an undefined code.

Difficult-to-read names like "utf_mbstowcs" are replaced with more
transparent names like "utf8s_to_utf16s" and the ordering of the
parameters is rationalized (buffer lengths come immediate after the
pointers they refer to, and the inputs precede the outputs).
Fortunately the low-level conversion routines are used in only a few
places; the interfaces to the higher-level uni2char and char2uni
methods have been left unchanged.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 11 deletions

diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index 9367b6297d84..89cd2deeb4af 100644
--- a/fs/befs/linuxvfs.c
+++ b/fs/befs/linuxvfs.c
@@ -513,7 +513,7 @@ befs_utf2nls(struct super_block *sb, const char *in,
 {
 	struct nls_table *nls = BEFS_SB(sb)->nls;
 	int i, o;
-	wchar_t uni;
+	unicode_t uni;
 	int unilen, utflen;
 	char *result;
 	/* The utf8->nls conversion won't make the final nls string bigger
@@ -539,16 +539,16 @@ befs_utf2nls(struct super_block *sb, const char *in,
 	for (i = o = 0; i < in_len; i += utflen, o += unilen) {
 
 		/* convert from UTF-8 to Unicode */
-		utflen = utf8_mbtowc(&uni, &in[i], in_len - i);
-		if (utflen < 0) {
+		utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
+		if (utflen < 0)
 			goto conv_err;
-		}
 
 		/* convert from Unicode to nls */
+		if (uni > MAX_WCHAR_T)
+			goto conv_err;
 		unilen = nls->uni2char(uni, &result[o], in_len - o);
-		if (unilen < 0) {
+		if (unilen < 0)
 			goto conv_err;
-		}
 	}
 	result[o] = '\0';
 	*out_len = o;
@@ -619,15 +619,13 @@ befs_nls2utf(struct super_block *sb, const char *in,
 
 		/* convert from nls to unicode */
 		unilen = nls->char2uni(&in[i], in_len - i, &uni);
-		if (unilen < 0) {
+		if (unilen < 0)
 			goto conv_err;
-		}
 
 		/* convert from unicode to UTF-8 */
-		utflen = utf8_wctomb(&result[o], uni, 3);
-		if (utflen <= 0) {
+		utflen = utf32_to_utf8(uni, &result[o], 3);
+		if (utflen <= 0)
 			goto conv_err;
-		}
 	}
 
 	result[o] = '\0';