/*
* udf_find_anchor
*
* PURPOSE
* Find an anchor volume descriptor.
*
* PRE-CONDITIONS
* sb Pointer to _locked_ superblock.
* lastblock Last block on media.
*
* POST-CONDITIONS
* <return> 1 if not found, 0 if ok
*
* HISTORY
* July 1, 1997 - Andrew E. Mileski
* Written, tested, and released.
*/
static void
udf_find_anchor(struct super_block *sb)
{
int lastblock = UDF_SB_LASTBLOCK(sb);
struct buffer_head *bh = NULL;
Uint16 ident;
Uint32 location;
int i;
if (lastblock)
{
int varlastblock = udf_variable_to_fixed(lastblock);
int last[] = { lastblock, lastblock - 2,
lastblock - 150, lastblock - 152,
varlastblock, varlastblock - 2,
varlastblock - 150, varlastblock - 152 };
lastblock = 0;
/* Search for an anchor volume descriptor pointer */
/* according to spec, anchor is in either:
* block 256
* lastblock-256
* lastblock
* however, if the disc isn't closed, it could be 512 */
for (i=0; (!lastblock && i<sizeof(last)/sizeof(int)); i++)
{
if (last[i] < 0 || !(bh = sb_bread(sb, last[i])))
{
ident = location = 0;
}
else
{
ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
udf_release_data(bh);
}
if (ident == TID_ANCHOR_VOL_DESC_PTR)
{
if (location == last[i] - UDF_SB_SESSION(sb))
{
lastblock = UDF_SB_ANCHOR(sb)[0] = last[i];
UDF_SB_ANCHOR(sb)[1] = last[i] - 256;
}
else if (location == udf_variable_to_fixed(last[i]) - UDF_SB_SESSION(sb))
{
UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
lastblock = UDF_SB_ANCHOR(sb)[0] = udf_variable_to_fixed(last[i]);
UDF_SB_ANCHOR(sb)[1] = lastblock - 256;
}
else
udf_debug("Anchor found at block %d, location mismatch %d.\n",
last[i], location);
}
else if (ident == TID_FILE_ENTRY || ident == TID_EXTENDED_FILE_ENTRY)
{
lastblock = last[i];
UDF_SB_ANCHOR(sb)[3] = 512 + UDF_SB_SESSION(sb);
}
else
{
if (last[i] < 256 || !(bh = sb_bread(sb, last[i] - 256)))
{
ident = location = 0;
}
else
{
ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
udf_release_data(bh);
}
if (ident == TID_ANCHOR_VOL_DESC_PTR &&
location == last[i] - 256 - UDF_SB_SESSION(sb))
{
lastblock = last[i];
UDF_SB_ANCHOR(sb)[1] = last[i] - 256;
}
else
{
if (last[i] < 312 + UDF_SB_SESSION(sb) || !(bh = sb_bread(sb, last[i] - 312 - UDF_SB_SESSION(sb))))
{
ident = location = 0;
}
else
{
ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
udf_release_data(bh);
}
if (ident == TID_ANCHOR_VOL_DESC_PTR &&
location == udf_variable_to_fixed(last[i]) - 256)
{
UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
lastblock = udf_variable_to_fixed(last[i]);
UDF_SB_ANCHOR(sb)[1] = lastblock - 256;
}
}
}
}
}
if (!lastblock)
{
/* We havn't found the lastblock. check 312 */
if ((bh = sb_bread(sb, 312 + UDF_SB_SESSION(sb))))
{
ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
udf_release_data(bh);
if (ident == TID_ANCHOR_VOL_DESC_PTR && location == 256)
UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
}
}
for (i=0; i<sizeof(UDF_SB_ANCHOR(sb))/sizeof(int); i++)
{
if (UDF_SB_ANCHOR(sb)[i])
{
if (!(bh = udf_read_tagged(sb,
UDF_SB_ANCHOR(sb)[i], UDF_SB_ANCHOR(sb)[i], &ident)))
{
UDF_SB_ANCHOR(sb)[i] = 0;
}
else
{
udf_release_data(bh);
if ((ident != TID_ANCHOR_VOL_DESC_PTR) && (i ||
(ident != TID_FILE_ENTRY && ident != TID_EXTENDED_FILE_ENTRY)))
{
UDF_SB_ANCHOR(sb)[i] = 0;
}
}
}
}
UDF_SB_LASTBLOCK(sb) = lastblock;
}
/*
* udf_read_tagged
*
* PURPOSE
* Read the first block of a tagged descriptor.
*
* HISTORY
* July 1, 1997 - Andrew E. Mileski
* Written, tested, and released.
*/
struct buffer_head *
udf_read_tagged(struct super_block *sb, uint32_t block, uint32_t location, uint16_t *ident)
{
tag *tag_p;
struct buffer_head *bh = NULL;
register uint8_t checksum;
register int i;
/* Read the block */
if (block == 0xFFFFFFFF)
return NULL;
bh = udf_tread(sb, block + UDF_SB_SESSION(sb));
if (!bh)
{
udf_debug("block=%d, location=%d: read failed\n", block + UDF_SB_SESSION(sb), location);
return NULL;
}
tag_p = (tag *)(bh->b_data);
*ident = le16_to_cpu(tag_p->tagIdent);
if ( location != le32_to_cpu(tag_p->tagLocation) )
{
udf_debug("location mismatch block %u, tag %u != %u\n",
block + UDF_SB_SESSION(sb), le32_to_cpu(tag_p->tagLocation), location);
goto error_out;
}
/* Verify the tag checksum */
checksum = 0U;
for (i = 0; i < 4; i++)
checksum += (uint8_t)(bh->b_data[i]);
for (i = 5; i < 16; i++)
checksum += (uint8_t)(bh->b_data[i]);
if (checksum != tag_p->tagChecksum) {
printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
goto error_out;
}
/* Verify the tag version */
if (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
le16_to_cpu(tag_p->descVersion) != 0x0003U)
{
udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
le16_to_cpu(tag_p->descVersion), block);
goto error_out;
}
/* Verify the descriptor CRC */
if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
le16_to_cpu(tag_p->descCRCLength), 0))
{
return bh;
}
udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
block + UDF_SB_SESSION(sb), le16_to_cpu(tag_p->descCRC), le16_to_cpu(tag_p->descCRCLength));
error_out:
brelse(bh);
return NULL;
}
static int
udf_vrs(struct super_block *sb, int silent)
{
struct VolStructDesc *vsd = NULL;
int sector = 32768;
int sectorsize;
struct buffer_head *bh = NULL;
int iso9660=0;
int nsr02=0;
int nsr03=0;
/* Block size must be a multiple of 512 */
if (sb->s_blocksize & 511)
return 0;
if (sb->s_blocksize < sizeof(struct VolStructDesc))
sectorsize = sizeof(struct VolStructDesc);
else
sectorsize = sb->s_blocksize;
sector += (UDF_SB_SESSION(sb) << sb->s_blocksize_bits);
udf_debug("Starting at sector %u (%ld byte sectors)\n",
(sector >> sb->s_blocksize_bits), sb->s_blocksize);
/* Process the sequence (if applicable) */
for (;!nsr02 && !nsr03; sector += sectorsize)
{
/* Read a block */
bh = udf_tread(sb, sector >> sb->s_blocksize_bits);
if (!bh)
break;
/* Look for ISO descriptors */
vsd = (struct VolStructDesc *)(bh->b_data +
(sector & (sb->s_blocksize - 1)));
if (vsd->stdIdent[0] == 0)
{
udf_release_data(bh);
break;
}
else if (!strncmp(vsd->stdIdent, STD_ID_CD001, STD_ID_LEN))
{
iso9660 = sector;
switch (vsd->structType)
{
case 0:
udf_debug("ISO9660 Boot Record found\n");
break;
case 1:
udf_debug("ISO9660 Primary Volume Descriptor found\n");
break;
case 2:
udf_debug("ISO9660 Supplementary Volume Descriptor found\n");
break;
case 3:
udf_debug("ISO9660 Volume Partition Descriptor found\n");
break;
case 255:
udf_debug("ISO9660 Volume Descriptor Set Terminator found\n");
break;
default:
udf_debug("ISO9660 VRS (%u) found\n", vsd->structType);
break;
}
}
else if (!strncmp(vsd->stdIdent, STD_ID_BEA01, STD_ID_LEN))
{
}
else if (!strncmp(vsd->stdIdent, STD_ID_TEA01, STD_ID_LEN))
{
udf_release_data(bh);
break;
}
else if (!strncmp(vsd->stdIdent, STD_ID_NSR02, STD_ID_LEN))
{
nsr02 = sector;
}
else if (!strncmp(vsd->stdIdent, STD_ID_NSR03, STD_ID_LEN))
{
nsr03 = sector;
}
udf_release_data(bh);
}
if (nsr03)
return nsr03;
else if (nsr02)
return nsr02;
else if (sector - (UDF_SB_SESSION(sb) << sb->s_blocksize_bits) == 32768)
return -1;
else
return 0;
}
