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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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