/*
 * volume_id - reads filesystem label and uuid
 *
 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
 *
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation; either
 *      version 2.1 of the License, or (at your option) any later version.
 *
 *      This library 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
 *      Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public
 *      License along with this library; if not, write to the Free Software
 *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "volume_id_internal.h"

struct volume_descriptor {
        struct descriptor_tag {
                uint16_t        id;
                uint16_t        version;
                uint8_t         checksum;
                uint8_t         reserved;
                uint16_t        serial;
                uint16_t        crc;
                uint16_t        crc_len;
                uint32_t        location;
        } PACKED tag;
        union {
                struct anchor_descriptor {
                        uint32_t        length;
                        uint32_t        location;
                } PACKED anchor;
                struct primary_descriptor {
                        uint32_t        seq_num;
                        uint32_t        desc_num;
                        struct dstring {
                                uint8_t clen;
                                uint8_t c[31];
                        } PACKED ident;
                } PACKED primary;
        } PACKED type;
} PACKED;

struct volume_structure_descriptor {
        uint8_t         type;
        uint8_t         id[5];
        uint8_t         version;
} PACKED;

#define UDF_VSD_OFFSET                  0x8000

int FAST_FUNC volume_id_probe_udf(struct volume_id *id /*,uint64_t off*/)
{
#define off ((uint64_t)0)
        struct volume_descriptor *vd;
        struct volume_structure_descriptor *vsd;
        unsigned bs;
        unsigned b;
        unsigned type;
        unsigned count;
        unsigned loc;
        unsigned clen;

        dbg("probing at offset 0x%llx", (unsigned long long) off);

        vsd = volume_id_get_buffer(id, off + UDF_VSD_OFFSET, 0x200);
        if (vsd == NULL)
                return -1;

        if (memcmp(vsd->id, "NSR02", 5) == 0)
                goto blocksize;
        if (memcmp(vsd->id, "NSR03", 5) == 0)
                goto blocksize;
        if (memcmp(vsd->id, "BEA01", 5) == 0)
                goto blocksize;
        if (memcmp(vsd->id, "BOOT2", 5) == 0)
                goto blocksize;
        if (memcmp(vsd->id, "CD001", 5) == 0)
                goto blocksize;
        if (memcmp(vsd->id, "CDW02", 5) == 0)
                goto blocksize;
        if (memcmp(vsd->id, "TEA03", 5) == 0)
                goto blocksize;
        return -1;

blocksize:
        /* search the next VSD to get the logical block size of the volume */
        for (bs = 0x800; bs < 0x8000; bs += 0x800) {
                vsd = volume_id_get_buffer(id, off + UDF_VSD_OFFSET + bs, 0x800);
                if (vsd == NULL)
                        return -1;
                dbg("test for blocksize: 0x%x", bs);
                if (vsd->id[0] != '\0')
                        goto nsr;
        }
        return -1;

nsr:
        /* search the list of VSDs for a NSR descriptor */
        for (b = 0; b < 64; b++) {
                vsd = volume_id_get_buffer(id, off + UDF_VSD_OFFSET + (b * bs), 0x800);
                if (vsd == NULL)
                        return -1;

                dbg("vsd: %c%c%c%c%c",
                    vsd->id[0], vsd->id[1], vsd->id[2], vsd->id[3], vsd->id[4]);

                if (vsd->id[0] == '\0')
                        return -1;
                if (memcmp(vsd->id, "NSR02", 5) == 0)
                        goto anchor;
                if (memcmp(vsd->id, "NSR03", 5) == 0)
                        goto anchor;
        }
        return -1;

anchor:
        /* read anchor volume descriptor */
        vd = volume_id_get_buffer(id, off + (256 * bs), 0x200);
        if (vd == NULL)
                return -1;

        type = le16_to_cpu(vd->tag.id);
        if (type != 2) /* TAG_ID_AVDP */
                goto found;

        /* get desriptor list address and block count */
        count = le32_to_cpu(vd->type.anchor.length) / bs;
        loc = le32_to_cpu(vd->type.anchor.location);
        dbg("0x%x descriptors starting at logical secor 0x%x", count, loc);

        /* pick the primary descriptor from the list */
        for (b = 0; b < count; b++) {
                vd = volume_id_get_buffer(id, off + ((loc + b) * bs), 0x200);
                if (vd == NULL)
                        return -1;

                type = le16_to_cpu(vd->tag.id);
                dbg("descriptor type %i", type);

                /* check validity */
                if (type == 0)
                        goto found;
                if (le32_to_cpu(vd->tag.location) != loc + b)
                        goto found;

                if (type == 1) /* TAG_ID_PVD */
                        goto pvd;
        }
        goto found;

 pvd:
//      volume_id_set_label_raw(id, &(vd->type.primary.ident.clen), 32);

        clen = vd->type.primary.ident.clen;
        dbg("label string charsize=%i bit", clen);
        if (clen == 8)
                volume_id_set_label_string(id, vd->type.primary.ident.c, 31);
        else if (clen == 16)
                volume_id_set_label_unicode16(id, vd->type.primary.ident.c, BE, 31);

 found:
//      volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
//      id->type = "udf";

        return 0;
}