/*      $NetBSD: ntfs.c,v 1.3 2021/12/02 14:26:12 christos Exp $        */

/*-
 * Copyright (c) 2017 The NetBSD Foundation, Inc.
 * Copyright (c) 2016 The DragonFly Project
 * Copyright (c) 2005 Takanori Watanabe
 * Copyright (c) 2014 The FreeBSD Foundation
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Tomohiro Kusumi <kusumi.tomohiro@gmail.com>.
 *
 * This software was developed by Edward Tomasz Napierala under sponsorship
 * from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <sys/cdefs.h>
__RCSID("$NetBSD: ntfs.c,v 1.3 2021/12/02 14:26:12 christos Exp $");

#include <err.h>
#include <iconv.h>
#include <langinfo.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "fstyp.h"

#define NTFS_A_VOLUMENAME       0x60
#define NTFS_FILEMAGIC          ((uint32_t)(0x454C4946))
#define NTFS_VOLUMEINO          3

struct ntfs_attr {
        uint32_t        a_type;
        uint32_t        reclen;
        uint8_t         a_flag;
        uint8_t         a_namelen;
        uint8_t         a_nameoff;
        uint8_t         reserved1;
        uint8_t         a_compression;
        uint8_t         reserved2;
        uint16_t        a_index;
        uint16_t        a_datalen;
        uint16_t        reserved3;
        uint16_t        a_dataoff;
        uint16_t        a_indexed;
} __packed;

struct ntfs_filerec {
        uint32_t        fr_hdrmagic;
        uint16_t        fr_hdrfoff;
        uint16_t        fr_hdrfnum;
        uint8_t         reserved[8];
        uint16_t        fr_seqnum;
        uint16_t        fr_nlink;
        uint16_t        fr_attroff;
        uint16_t        fr_flags;
        uint32_t        fr_size;
        uint32_t        fr_allocated;
        uint64_t        fr_mainrec;
        uint16_t        fr_attrnum;
} __packed;

struct ntfs_bootfile {
        uint8_t         reserved1[3];
        uint8_t         bf_sysid[8];
        uint16_t        bf_bps;
        uint8_t         bf_spc;
        uint8_t         reserved2[7];
        uint8_t         bf_media;
        uint8_t         reserved3[2];
        uint16_t        bf_spt;
        uint16_t        bf_heads;
        uint8_t         reserver4[12];
        uint64_t        bf_spv;
        uint64_t        bf_mftcn;
        uint64_t        bf_mftmirrcn;
        int8_t          bf_mftrecsz;
        uint32_t        bf_ibsz;
        uint32_t        bf_volsn;
} __packed;

static void
convert_label(const void *label /* LE */, size_t labellen, char *label_out,
    size_t label_sz)
{
        char *label_out_orig;
        iconv_t cd;
        size_t rc;

        cd = iconv_open(nl_langinfo(CODESET), NTFS_ENC);
        if (cd == (iconv_t)-1) {
                warn("ntfs: Could not open iconv");
                return;
        }

        label_out_orig = label_out;

        rc = iconv(cd, __UNCONST(&label), &labellen, &label_out,
            &label_sz);
        if (rc == (size_t)-1) {
                warn("ntfs: iconv()");
                *label_out_orig = '\0';
        } else {
                /* NUL-terminate result (iconv advances label_out). */
                if (label_sz == 0)
                        label_out--;
                *label_out = '\0';
        }

        iconv_close(cd);
}

int
fstyp_ntfs(FILE *fp, char *label, size_t size)
{
        struct ntfs_bootfile *bf;
        struct ntfs_filerec *fr;
        struct ntfs_attr *atr;
        off_t voloff;
        char *filerecp, *ap;
        int8_t mftrecsz;
        size_t recsize;

        filerecp = NULL;

        bf = read_buf(fp, 0, 512);
        if (bf == NULL || strncmp((char*)bf->bf_sysid, "NTFS    ", 8) != 0)
                goto fail;
        if (!show_label)
                goto ok;

        mftrecsz = bf->bf_mftrecsz;
        recsize = mftrecsz > 0 ? (size_t)(mftrecsz * bf->bf_bps * bf->bf_spc)
            : (size_t)(1 << -mftrecsz);

        voloff = (off_t)((off_t)bf->bf_mftcn * bf->bf_spc * bf->bf_bps +
            (off_t)recsize * NTFS_VOLUMEINO);

        filerecp = read_buf(fp, voloff, recsize);
        if (filerecp == NULL)
                goto fail;
        fr = (struct ntfs_filerec *)filerecp;

        if (fr->fr_hdrmagic != NTFS_FILEMAGIC)
                goto fail;

        for (ap = filerecp + fr->fr_attroff;
            atr = (struct ntfs_attr *)ap, (int)atr->a_type != -1;
            ap += atr->reclen) {
                if (atr->a_type != NTFS_A_VOLUMENAME)
                        continue;

                convert_label(ap + atr->a_dataoff,
                    atr->a_datalen, label, size);
                break;
        }

ok:
        free(bf);
        free(filerecp);

        return 0;

fail:
        free(bf);
        free(filerecp);

        return 1;
}