/*      $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 <[email protected]>.
*
* 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;
}