microsoft
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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/udf/misc.c

314 строки
7.9 KiB
C
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/*
* misc.c
*
* PURPOSE
* Miscellaneous routines for the OSTA-UDF(tm) filesystem.
*
* CONTACTS
* E-mail regarding any portion of the Linux UDF file system should be
* directed to the development team mailing list (run by majordomo):
* linux_udf@hpesjro.fc.hp.com
*
* COPYRIGHT
* This file is distributed under the terms of the GNU General Public
* License (GPL). Copies of the GPL can be obtained from:
* ftp://prep.ai.mit.edu/pub/gnu/GPL
* Each contributing author retains all rights to their own work.
*
* (C) 1998 Dave Boynton
* (C) 1998-2004 Ben Fennema
* (C) 1999-2000 Stelias Computing Inc
*
* HISTORY
*
* 04/19/99 blf partial support for reading/writing specific EA's
*/
#include "udfdecl.h"
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/udf_fs.h>
#include <linux/buffer_head.h>
#include "udf_i.h"
#include "udf_sb.h"
struct buffer_head *
udf_tgetblk(struct super_block *sb, int block)
{
if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
return sb_getblk(sb, udf_fixed_to_variable(block));
else
return sb_getblk(sb, block);
}
struct buffer_head *
udf_tread(struct super_block *sb, int block)
{
if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
return sb_bread(sb, udf_fixed_to_variable(block));
else
return sb_bread(sb, block);
}
struct genericFormat *
udf_add_extendedattr(struct inode * inode, uint32_t size, uint32_t type,
uint8_t loc)
{
uint8_t *ea = NULL, *ad = NULL;
int offset;
uint16_t crclen;
int i;
ea = UDF_I_DATA(inode);
if (UDF_I_LENEATTR(inode))
ad = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
else
{
ad = ea;
size += sizeof(struct extendedAttrHeaderDesc);
}
offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
UDF_I_LENALLOC(inode);
/* TODO - Check for FreeEASpace */
if (loc & 0x01 && offset >= size)
{
struct extendedAttrHeaderDesc *eahd;
eahd = (struct extendedAttrHeaderDesc *)ea;
if (UDF_I_LENALLOC(inode))
{
memmove(&ad[size], ad, UDF_I_LENALLOC(inode));
}
if (UDF_I_LENEATTR(inode))
{
/* check checksum/crc */
if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum)
{
return NULL;
}
}
else
{
size -= sizeof(struct extendedAttrHeaderDesc);
UDF_I_LENEATTR(inode) += sizeof(struct extendedAttrHeaderDesc);
eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
if (UDF_SB_UDFREV(inode->i_sb) >= 0x0200)
eahd->descTag.descVersion = cpu_to_le16(3);
else
eahd->descTag.descVersion = cpu_to_le16(2);
eahd->descTag.tagSerialNum = cpu_to_le16(UDF_SB_SERIALNUM(inode->i_sb));
eahd->descTag.tagLocation = cpu_to_le32(UDF_I_LOCATION(inode).logicalBlockNum);
eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
}
offset = UDF_I_LENEATTR(inode);
if (type < 2048)
{
if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode))
{
uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
memmove(&ea[offset - aal + size],
&ea[aal], offset - aal);
offset -= aal;
eahd->appAttrLocation = cpu_to_le32(aal + size);
}
if (le32_to_cpu(eahd->impAttrLocation) < UDF_I_LENEATTR(inode))
{
uint32_t ial = le32_to_cpu(eahd->impAttrLocation);
memmove(&ea[offset - ial + size],
&ea[ial], offset - ial);
offset -= ial;
eahd->impAttrLocation = cpu_to_le32(ial + size);
}
}
else if (type < 65536)
{
if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode))
{
uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
memmove(&ea[offset - aal + size],
&ea[aal], offset - aal);
offset -= aal;
eahd->appAttrLocation = cpu_to_le32(aal + size);
}
}
/* rewrite CRC + checksum of eahd */
crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
eahd->descTag.descCRCLength = cpu_to_le16(crclen);
eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd + sizeof(tag), crclen, 0));
eahd->descTag.tagChecksum = 0;
for (i=0; i<16; i++)
if (i != 4)
eahd->descTag.tagChecksum += ((uint8_t *)&(eahd->descTag))[i];
UDF_I_LENEATTR(inode) += size;
return (struct genericFormat *)&ea[offset];
}
if (loc & 0x02)
{
}
return NULL;
}
struct genericFormat *
udf_get_extendedattr(struct inode *inode, uint32_t type, uint8_t subtype)
{
struct genericFormat *gaf;
uint8_t *ea = NULL;
uint32_t offset;
ea = UDF_I_DATA(inode);
if (UDF_I_LENEATTR(inode))
{
struct extendedAttrHeaderDesc *eahd;
eahd = (struct extendedAttrHeaderDesc *)ea;
/* check checksum/crc */
if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum)
{
return NULL;
}
if (type < 2048)
offset = sizeof(struct extendedAttrHeaderDesc);
else if (type < 65536)
offset = le32_to_cpu(eahd->impAttrLocation);
else
offset = le32_to_cpu(eahd->appAttrLocation);
while (offset < UDF_I_LENEATTR(inode))
{
gaf = (struct genericFormat *)&ea[offset];
if (le32_to_cpu(gaf->attrType) == type && gaf->attrSubtype == subtype)
return gaf;
else
offset += le32_to_cpu(gaf->attrLength);
}
}
return NULL;
}
/*
* 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;
}
struct buffer_head *
udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc, uint32_t offset, uint16_t *ident)
{
return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
loc.logicalBlockNum + offset, ident);
}
void udf_release_data(struct buffer_head *bh)
{
if (bh)
brelse(bh);
}
void udf_update_tag(char *data, int length)
{
tag *tptr = (tag *)data;
int i;
length -= sizeof(tag);
tptr->tagChecksum = 0;
tptr->descCRCLength = cpu_to_le16(length);
tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
for (i=0; i<16; i++)
if (i != 4)
tptr->tagChecksum += (uint8_t)(data[i]);
}
void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
uint32_t loc, int length)
{
tag *tptr = (tag *)data;
tptr->tagIdent = cpu_to_le16(ident);
tptr->descVersion = cpu_to_le16(version);
tptr->tagSerialNum = cpu_to_le16(snum);
tptr->tagLocation = cpu_to_le32(loc);
udf_update_tag(data, length);
}
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