unistr.c

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/*
 * unistr.c - NTFS Unicode string handling. Part of the Linux-NTFS project.
 *
 * Copyright (c) 2001-2006 Anton Altaparmakov
 *
 * This program/include file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (in the main directory of the Linux-NTFS
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/slab.h>

#include "types.h"
#include "debug.h"
#include "ntfs.h"

/*
 * IMPORTANT
 * =========
 *
 * All these routines assume that the Unicode characters are in little endian
 * encoding inside the strings!!!
 */

/*
 * This is used by the name collation functions to quickly determine what
 * characters are (in)valid.
 */
static const u8 legal_ansi_char_array[0x40] = {
    0x00, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,

    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,

    0x17, 0x07, 0x18, 0x17, 0x17, 0x17, 0x17, 0x17,
    0x17, 0x17, 0x18, 0x16, 0x16, 0x17, 0x07, 0x00,

    0x17, 0x17, 0x17, 0x17, 0x17, 0x17, 0x17, 0x17,
    0x17, 0x17, 0x04, 0x16, 0x18, 0x16, 0x18, 0x18,
};

bool ntfs_are_names_equal(const ntfschar *s1, size_t s1_len,
        const ntfschar *s2, size_t s2_len, const IGNORE_CASE_BOOL ic,
        const ntfschar *upcase, const u32 upcase_size)
{
    if (s1_len != s2_len)
        return false;
    if (ic == CASE_SENSITIVE)
        return !ntfs_ucsncmp(s1, s2, s1_len);
    return !ntfs_ucsncasecmp(s1, s2, s1_len, upcase, upcase_size);
}

int ntfs_collate_names(const ntfschar *name1, const u32 name1_len,
        const ntfschar *name2, const u32 name2_len,
        const int err_val, const IGNORE_CASE_BOOL ic,
        const ntfschar *upcase, const u32 upcase_len)
{
    u32 cnt, min_len;
    u16 c1, c2;

    min_len = name1_len;
    if (name1_len > name2_len)
        min_len = name2_len;
    for (cnt = 0; cnt < min_len; ++cnt) {
        c1 = le16_to_cpu(*name1++);
        c2 = le16_to_cpu(*name2++);
        if (ic) {
            if (c1 < upcase_len)
                c1 = le16_to_cpu(upcase[c1]);
            if (c2 < upcase_len)
                c2 = le16_to_cpu(upcase[c2]);
        }
        if (c1 < 64 && legal_ansi_char_array[c1] & 8)
            return err_val;
        if (c1 < c2)
            return -1;
        if (c1 > c2)
            return 1;
    }
    if (name1_len < name2_len)
        return -1;
    if (name1_len == name2_len)
        return 0;
    /* name1_len > name2_len */
    c1 = le16_to_cpu(*name1);
    if (c1 < 64 && legal_ansi_char_array[c1] & 8)
        return err_val;
    return 1;
}

int ntfs_ucsncmp(const ntfschar *s1, const ntfschar *s2, size_t n)
{
    u16 c1, c2;
    size_t i;

    for (i = 0; i < n; ++i) {
        c1 = le16_to_cpu(s1[i]);
        c2 = le16_to_cpu(s2[i]);
        if (c1 < c2)
            return -1;
        if (c1 > c2)
            return 1;
        if (!c1)
            break;
    }
    return 0;
}

int ntfs_ucsncasecmp(const ntfschar *s1, const ntfschar *s2, size_t n,
        const ntfschar *upcase, const u32 upcase_size)
{
    size_t i;
    u16 c1, c2;

    for (i = 0; i < n; ++i) {
        if ((c1 = le16_to_cpu(s1[i])) < upcase_size)
            c1 = le16_to_cpu(upcase[c1]);
        if ((c2 = le16_to_cpu(s2[i])) < upcase_size)
            c2 = le16_to_cpu(upcase[c2]);
        if (c1 < c2)
            return -1;
        if (c1 > c2)
            return 1;
        if (!c1)
            break;
    }
    return 0;
}

void ntfs_upcase_name(ntfschar *name, u32 name_len, const ntfschar *upcase,
        const u32 upcase_len)
{
    u32 i;
    u16 u;

    for (i = 0; i < name_len; i++)
        if ((u = le16_to_cpu(name[i])) < upcase_len)
            name[i] = upcase[u];
}

void ntfs_file_upcase_value(FILE_NAME_ATTR *file_name_attr,
        const ntfschar *upcase, const u32 upcase_len)
{
    ntfs_upcase_name((ntfschar*)&file_name_attr->file_name,
            file_name_attr->file_name_length, upcase, upcase_len);
}

int ntfs_file_compare_values(FILE_NAME_ATTR *file_name_attr1,
        FILE_NAME_ATTR *file_name_attr2,
        const int err_val, const IGNORE_CASE_BOOL ic,
        const ntfschar *upcase, const u32 upcase_len)
{
    return ntfs_collate_names((ntfschar*)&file_name_attr1->file_name,
            file_name_attr1->file_name_length,
            (ntfschar*)&file_name_attr2->file_name,
            file_name_attr2->file_name_length,
            err_val, ic, upcase, upcase_len);
}

int ntfs_nlstoucs(const ntfs_volume *vol, const char *ins,
        const int ins_len, ntfschar **outs)
{
    struct nls_table *nls = vol->nls_map;
    ntfschar *ucs;
    wchar_t wc;
    int i, o, wc_len;

    /* We do not trust outside sources. */
    if (likely(ins)) {
        ucs = kmem_cache_alloc(ntfs_name_cache, GFP_NOFS);
        if (likely(ucs)) {
            for (i = o = 0; i < ins_len; i += wc_len) {
                wc_len = nls->char2uni(ins + i, ins_len - i,
                        &wc);
                if (likely(wc_len >= 0 &&
                        o < NTFS_MAX_NAME_LEN)) {
                    if (likely(wc)) {
                        ucs[o++] = cpu_to_le16(wc);
                        continue;
                    } /* else if (!wc) */
                    break;
                } /* else if (wc_len < 0 ||
                        o >= NTFS_MAX_NAME_LEN) */
                goto name_err;
            }
            ucs[o] = 0;
            *outs = ucs;
            return o;
        } /* else if (!ucs) */
        ntfs_error(vol->sb, "Failed to allocate buffer for converted "
                "name from ntfs_name_cache.");
        return -ENOMEM;
    } /* else if (!ins) */
    ntfs_error(vol->sb, "Received NULL pointer.");
    return -EINVAL;
name_err:
    kmem_cache_free(ntfs_name_cache, ucs);
    if (wc_len < 0) {
        ntfs_error(vol->sb, "Name using character set %s contains "
                "characters that cannot be converted to "
                "Unicode.", nls->charset);
        i = -EILSEQ;
    } else /* if (o >= NTFS_MAX_NAME_LEN) */ {
        ntfs_error(vol->sb, "Name is too long (maximum length for a "
                "name on NTFS is %d Unicode characters.",
                NTFS_MAX_NAME_LEN);
        i = -ENAMETOOLONG;
    }
    return i;
}

int ntfs_ucstonls(const ntfs_volume *vol, const ntfschar *ins,
        const int ins_len, unsigned char **outs, int outs_len)
{
    struct nls_table *nls = vol->nls_map;
    unsigned char *ns;
    int i, o, ns_len, wc;

    /* We don't trust outside sources. */
    if (ins) {
        ns = *outs;
        ns_len = outs_len;
        if (ns && !ns_len) {
            wc = -ENAMETOOLONG;
            goto conversion_err;
        }
        if (!ns) {
            ns_len = ins_len * NLS_MAX_CHARSET_SIZE;
            ns = kmalloc(ns_len + 1, GFP_NOFS);
            if (!ns)
                goto mem_err_out;
        }
        for (i = o = 0; i < ins_len; i++) {
retry:          wc = nls->uni2char(le16_to_cpu(ins[i]), ns + o,
                    ns_len - o);
            if (wc > 0) {
                o += wc;
                continue;
            } else if (!wc)
                break;
            else if (wc == -ENAMETOOLONG && ns != *outs) {
                unsigned char *tc;
                /* Grow in multiples of 64 bytes. */
                tc = kmalloc((ns_len + 64) &
                        ~63, GFP_NOFS);
                if (tc) {
                    memcpy(tc, ns, ns_len);
                    ns_len = ((ns_len + 64) & ~63) - 1;
                    kfree(ns);
                    ns = tc;
                    goto retry;
                } /* No memory so goto conversion_error; */
            } /* wc < 0, real error. */
            goto conversion_err;
        }
        ns[o] = 0;
        *outs = ns;
        return o;
    } /* else (!ins) */
    ntfs_error(vol->sb, "Received NULL pointer.");
    return -EINVAL;
conversion_err:
    ntfs_error(vol->sb, "Unicode name contains characters that cannot be "
            "converted to character set %s.  You might want to "
            "try to use the mount option nls=utf8.", nls->charset);
    if (ns != *outs)
        kfree(ns);
    if (wc != -ENAMETOOLONG)
        wc = -EILSEQ;
    return wc;
mem_err_out:
    ntfs_error(vol->sb, "Failed to allocate name!");
    return -ENOMEM;
}