source: MondoRescue/branches/3.3/mindi-busybox/util-linux/volume_id/udf.c@ 3625

/*
 * 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
 */

//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_UDF) += udf.o

//config:
//config:config FEATURE_VOLUMEID_UDF
//config:   bool "udf filesystem"
//config:   default y
//config:   depends on VOLUMEID
//config:   help
//config:     TODO
//config:

#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);
    IF_FEATURE_BLKID_TYPE(id->type = "udf";)
    return 0;
}