linux-kernel - [PATCH v2] Convert properly UTF-8 to UTF-16

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Date:	Tue, 7 Aug 2012 10:33:03 +0100
From:	Frediano Ziglio <frediano.ziglio@...rix.com>
To:	"sfrench@...ba.org" <sfrench@...ba.org>,
	"jlayton@...hat.com" <jlayton@...hat.com>
CC:	"linux-cifs@...r.kernel.org" <linux-cifs@...r.kernel.org>,
	"samba-technical@...ts.samba.org" <samba-technical@...ts.samba.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] Convert properly UTF-8 to UTF-16


wchar_t is currently 16bit so converting a utf8 encoded characters not
in plane 0 (>= 0x10000) to wchar_t (that is calling char2uni) lead to a
-EINVAL return. This patch detect utf8 in cifs_strtoUTF16 and add special
code calling utf8s_to_utf16s.

Signed-off-by: Frediano Ziglio <frediano.ziglio@...rix.com>
---
 fs/cifs/cifs_unicode.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/cifs_unicode.c b/fs/cifs/cifs_unicode.c
index 7dab9c0..1166b95 100644
--- a/fs/cifs/cifs_unicode.c
+++ b/fs/cifs/cifs_unicode.c
@@ -203,6 +203,27 @@ cifs_strtoUTF16(__le16 *to, const char *from, int len,
 	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) {
@@ -215,6 +236,7 @@ cifs_strtoUTF16(__le16 *to, const char *from, int len,
 		put_unaligned_le16(wchar_to, &to[i]);
 	}
 
+success:
 	put_unaligned_le16(0, &to[i]);
 	return i;
 }
-- 
1.7.5.4