fs/udf/misc.c - kernel/common - Git at Google

 /*
  * misc.c
  *
  * PURPOSE
  *	Miscellaneous routines for the OSTA-UDF(tm) filesystem.
  *
  * 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/crc-itu-t.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;
 	struct udf_inode_info *iinfo = UDF_I(inode);

 	ea = iinfo->i_ext.i_data;
 	if (iinfo->i_lenEAttr) {
 		ad = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
 	} else {
 		ad = ea;
 		size += sizeof(struct extendedAttrHeaderDesc);
 	}

 	offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
 		iinfo->i_lenAlloc;

 	/* TODO - Check for FreeEASpace */

 	if (loc & 0x01 && offset >= size) {
 		struct extendedAttrHeaderDesc *eahd;
 		eahd = (struct extendedAttrHeaderDesc *)ea;

 		if (iinfo->i_lenAlloc)
 			memmove(&ad[size], ad, iinfo->i_lenAlloc);

 		if (iinfo->i_lenEAttr) {
 			/* check checksum/crc */
 			if (eahd->descTag.tagIdent !=
 					cpu_to_le16(TAG_IDENT_EAHD) ||
 			    le32_to_cpu(eahd->descTag.tagLocation) !=
 					iinfo->i_location.logicalBlockNum)
 				return NULL;
 		} else {
 			struct udf_sb_info *sbi = UDF_SB(inode->i_sb);

 			size -= sizeof(struct extendedAttrHeaderDesc);
 			iinfo->i_lenEAttr +=
 				sizeof(struct extendedAttrHeaderDesc);
 			eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
 			if (sbi->s_udfrev >= 0x0200)
 				eahd->descTag.descVersion = cpu_to_le16(3);
 			else
 				eahd->descTag.descVersion = cpu_to_le16(2);
 			eahd->descTag.tagSerialNum =
 					cpu_to_le16(sbi->s_serial_number);
 			eahd->descTag.tagLocation = cpu_to_le32(
 					iinfo->i_location.logicalBlockNum);
 			eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
 			eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
 		}

 		offset = iinfo->i_lenEAttr;
 		if (type < 2048) {
 			if (le32_to_cpu(eahd->appAttrLocation) <
 					iinfo->i_lenEAttr) {
 				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) <
 					iinfo->i_lenEAttr) {
 				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) <
 					iinfo->i_lenEAttr) {
 				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(struct tag);
 		eahd->descTag.descCRCLength = cpu_to_le16(crclen);
 		eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
 						sizeof(struct tag), crclen));
 		eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
 		iinfo->i_lenEAttr += 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;
 	struct udf_inode_info *iinfo = UDF_I(inode);

 	ea = iinfo->i_ext.i_data;

 	if (iinfo->i_lenEAttr) {
 		struct extendedAttrHeaderDesc *eahd;
 		eahd = (struct extendedAttrHeaderDesc *)ea;

 		/* check checksum/crc */
 		if (eahd->descTag.tagIdent !=
 				cpu_to_le16(TAG_IDENT_EAHD) ||
 		    le32_to_cpu(eahd->descTag.tagLocation) !=
 				iinfo->i_location.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 < iinfo->i_lenEAttr) {
 			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)
 {
 	struct tag *tag_p;
 	struct buffer_head *bh = NULL;
 	u8 checksum;

 	/* Read the block */
 	if (block == 0xFFFFFFFF)
 		return NULL;

 	bh = udf_tread(sb, block);
 	if (!bh) {
 		udf_err(sb, "read failed, block=%u, location=%d\n",
 			block, location);
 		return NULL;
 	}

 	tag_p = (struct 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, le32_to_cpu(tag_p->tagLocation), location);
 		goto error_out;
 	}

 	/* Verify the tag checksum */
 	checksum = udf_tag_checksum(tag_p);
 	if (checksum != tag_p->tagChecksum) {
 		udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
 			block, checksum, tag_p->tagChecksum);
 		goto error_out;
 	}

 	/* Verify the tag version */
 	if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
 	    tag_p->descVersion != cpu_to_le16(0x0003U)) {
 		udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
 			le16_to_cpu(tag_p->descVersion), block);
 		goto error_out;
 	}

 	/* Verify the descriptor CRC */
 	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
 	    le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
 					bh->b_data + sizeof(struct tag),
 					le16_to_cpu(tag_p->descCRCLength)))
 		return bh;

 	udf_debug("Crc failure block %d: crc = %d, crclen = %d\n", block,
 		  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,
 				     struct 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_update_tag(char *data, int length)
 {
 	struct tag *tptr = (struct tag *)data;
 	length -= sizeof(struct tag);

 	tptr->descCRCLength = cpu_to_le16(length);
 	tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
 	tptr->tagChecksum = udf_tag_checksum(tptr);
 }

 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
 		 uint32_t loc, int length)
 {
 	struct tag *tptr = (struct 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);
 }

 u8 udf_tag_checksum(const struct tag *t)
 {
 	u8 *data = (u8 *)t;
 	u8 checksum = 0;
 	int i;
 	for (i = 0; i < sizeof(struct tag); ++i)
 		if (i != 4) /* position of checksum */
 			checksum += data[i];
 	return checksum;
 }
	/*
	* misc.c
	*
	* PURPOSE
	* Miscellaneous routines for the OSTA-UDF(tm) filesystem.
	*
	* 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/crc-itu-t.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;
	struct udf_inode_info *iinfo = UDF_I(inode);

	ea = iinfo->i_ext.i_data;
	if (iinfo->i_lenEAttr) {
	ad = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
	} else {
	ad = ea;
	size += sizeof(struct extendedAttrHeaderDesc);
	}

	offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
	iinfo->i_lenAlloc;

	/* TODO - Check for FreeEASpace */

	if (loc & 0x01 && offset >= size) {
	struct extendedAttrHeaderDesc *eahd;
	eahd = (struct extendedAttrHeaderDesc *)ea;

	if (iinfo->i_lenAlloc)
	memmove(&ad[size], ad, iinfo->i_lenAlloc);

	if (iinfo->i_lenEAttr) {
	/* check checksum/crc */
	if (eahd->descTag.tagIdent !=
	cpu_to_le16(TAG_IDENT_EAHD) \|\|
	le32_to_cpu(eahd->descTag.tagLocation) !=
	iinfo->i_location.logicalBlockNum)
	return NULL;
	} else {
	struct udf_sb_info *sbi = UDF_SB(inode->i_sb);

	size -= sizeof(struct extendedAttrHeaderDesc);
	iinfo->i_lenEAttr +=
	sizeof(struct extendedAttrHeaderDesc);
	eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
	if (sbi->s_udfrev >= 0x0200)
	eahd->descTag.descVersion = cpu_to_le16(3);
	else
	eahd->descTag.descVersion = cpu_to_le16(2);
	eahd->descTag.tagSerialNum =
	cpu_to_le16(sbi->s_serial_number);
	eahd->descTag.tagLocation = cpu_to_le32(
	iinfo->i_location.logicalBlockNum);
	eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
	eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
	}

	offset = iinfo->i_lenEAttr;
	if (type < 2048) {
	if (le32_to_cpu(eahd->appAttrLocation) <
	iinfo->i_lenEAttr) {
	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) <
	iinfo->i_lenEAttr) {
	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) <
	iinfo->i_lenEAttr) {
	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(struct tag);
	eahd->descTag.descCRCLength = cpu_to_le16(crclen);
	eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
	sizeof(struct tag), crclen));
	eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
	iinfo->i_lenEAttr += 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;
	struct udf_inode_info *iinfo = UDF_I(inode);

	ea = iinfo->i_ext.i_data;

	if (iinfo->i_lenEAttr) {
	struct extendedAttrHeaderDesc *eahd;
	eahd = (struct extendedAttrHeaderDesc *)ea;

	/* check checksum/crc */
	if (eahd->descTag.tagIdent !=
	cpu_to_le16(TAG_IDENT_EAHD) \|\|
	le32_to_cpu(eahd->descTag.tagLocation) !=
	iinfo->i_location.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 < iinfo->i_lenEAttr) {
	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)
	{
	struct tag *tag_p;
	struct buffer_head *bh = NULL;
	u8 checksum;

	/* Read the block */
	if (block == 0xFFFFFFFF)
	return NULL;

	bh = udf_tread(sb, block);
	if (!bh) {
	udf_err(sb, "read failed, block=%u, location=%d\n",
	block, location);
	return NULL;
	}

	tag_p = (struct 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, le32_to_cpu(tag_p->tagLocation), location);
	goto error_out;
	}

	/* Verify the tag checksum */
	checksum = udf_tag_checksum(tag_p);
	if (checksum != tag_p->tagChecksum) {
	udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
	block, checksum, tag_p->tagChecksum);
	goto error_out;
	}

	/* Verify the tag version */
	if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
	tag_p->descVersion != cpu_to_le16(0x0003U)) {
	udf_err(sb, "tag version 0x%04x != 0x0002 \|\| 0x0003, block %u\n",
	le16_to_cpu(tag_p->descVersion), block);
	goto error_out;
	}

	/* Verify the descriptor CRC */
	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize \|\|
	le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
	bh->b_data + sizeof(struct tag),
	le16_to_cpu(tag_p->descCRCLength)))
	return bh;

	udf_debug("Crc failure block %d: crc = %d, crclen = %d\n", block,
	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,
	struct 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_update_tag(char *data, int length)
	{
	struct tag tptr = (struct tag )data;
	length -= sizeof(struct tag);

	tptr->descCRCLength = cpu_to_le16(length);
	tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
	tptr->tagChecksum = udf_tag_checksum(tptr);
	}

	void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
	uint32_t loc, int length)
	{
	struct tag tptr = (struct 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);
	}

	u8 udf_tag_checksum(const struct tag *t)
	{
	u8 data = (u8 )t;
	u8 checksum = 0;
	int i;
	for (i = 0; i < sizeof(struct tag); ++i)
	if (i != 4) /* position of checksum */
	checksum += data[i];
	return checksum;
	}