/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 Takanori Watanabe
 * All rights reserved.
 *
 * 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/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>

#include <geom/geom.h>
#include <geom/label/g_label.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
g_label_ntfs_taste(struct g_consumer *cp, char *label, size_t size)
{
        struct g_provider *pp;
        struct ntfs_bootfile *bf;
        struct ntfs_filerec *fr;
        struct ntfs_attr *atr;
        off_t voloff;
        size_t recoff;
        char *filerecp;
        int8_t mftrecsz;
        char vnchar;
        int recsize, j;

        g_topology_assert_not();

        label[0] = '\0';
        pp = cp->provider;
        bf = NULL;
        filerecp = NULL;

        if (pp->sectorsize < sizeof(*bf))
                goto done;

        bf = g_read_data(cp, 0, pp->sectorsize, NULL);
        if (bf == NULL || strncmp(bf->bf_sysid, "NTFS    ", 8) != 0)
                goto done;

        mftrecsz = bf->bf_mftrecsz;
        recsize = (mftrecsz > 0) ? (mftrecsz * bf->bf_bps * bf->bf_spc) :
            (1 << -mftrecsz);
        if (recsize <= 0 || recsize > maxphys || recsize % pp->sectorsize != 0)
                goto done;

        voloff = bf->bf_mftcn * bf->bf_spc * bf->bf_bps +
            recsize * NTFS_VOLUMEINO;
        if (voloff % pp->sectorsize != 0)
                goto done;

        filerecp = g_read_data(cp, voloff, recsize, NULL);
        if (filerecp == NULL)
                goto done;
        fr = (struct ntfs_filerec *)filerecp;
        if (fr->fr_hdrmagic != NTFS_FILEMAGIC)
                goto done;

        for (recoff = fr->fr_attroff;
            recoff <= recsize - 2 * sizeof(uint32_t);
            recoff += atr->reclen) {
                atr = (struct ntfs_attr *)(filerecp + recoff);
                if (atr->a_type == -1)
                        break;
                if (atr->reclen < sizeof(*atr))
                        break;
                if (recsize - recoff < atr->reclen)
                        break;
                if (atr->a_type == NTFS_A_VOLUMENAME) {
                        if (atr->a_dataoff > atr->reclen ||
                            atr->a_datalen > atr->reclen - atr->a_dataoff)
                                break;

                        /*
                         * UNICODE to ASCII.
                         * Should we need to use iconv(9)?
                         */
                        if (atr->a_datalen >= size * 2 ||
                            atr->a_datalen % 2 != 0)
                                break;
                        for (j = 0; j < atr->a_datalen; j++) {
                                vnchar = ((char *)atr)[atr->a_dataoff + j];
                                if (j & 1) {
                                        if (vnchar) {
                                                label[0] = 0;
                                                goto done;
                                        }
                                } else {
                                        label[j / 2] = vnchar;
                                }
                        }
                        label[j / 2] = 0;
                        break;
                }
        }
done:
        g_free(bf);
        g_free(filerecp);
}

struct g_label_desc g_label_ntfs = {
        .ld_taste = g_label_ntfs_taste,
        .ld_dirprefix = "ntfs/",
        .ld_enabled = 1
};

G_LABEL_INIT(ntfs, g_label_ntfs, "Create device nodes for NTFS volumes");