1/*
2 * misc.c
3 *
4 * PURPOSE
5 *	Miscellaneous routines for the OSTA-UDF(tm) filesystem.
6 *
7 * COPYRIGHT
8 *	This file is distributed under the terms of the GNU General Public
9 *	License (GPL). Copies of the GPL can be obtained from:
10 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
11 *	Each contributing author retains all rights to their own work.
12 *
13 *  (C) 1998 Dave Boynton
14 *  (C) 1998-2004 Ben Fennema
15 *  (C) 1999-2000 Stelias Computing Inc
16 *
17 * HISTORY
18 *
19 *  04/19/99 blf  partial support for reading/writing specific EA's
20 */
21
22#include "udfdecl.h"
23
24#include <linux/fs.h>
25#include <linux/string.h>
26#include <linux/udf_fs.h>
27#include <linux/buffer_head.h>
28
29#include "udf_i.h"
30#include "udf_sb.h"
31
32struct buffer_head *
33udf_tgetblk(struct super_block *sb, int block)
34{
35	if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
36		return sb_getblk(sb, udf_fixed_to_variable(block));
37	else
38		return sb_getblk(sb, block);
39}
40
41struct buffer_head *
42udf_tread(struct super_block *sb, int block)
43{
44	if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
45		return sb_bread(sb, udf_fixed_to_variable(block));
46	else
47		return sb_bread(sb, block);
48}
49
50struct genericFormat *
51udf_add_extendedattr(struct inode * inode, uint32_t size, uint32_t type,
52	uint8_t loc)
53{
54	uint8_t *ea = NULL, *ad = NULL;
55	int offset;
56	uint16_t crclen;
57	int i;
58
59	ea = UDF_I_DATA(inode);
60	if (UDF_I_LENEATTR(inode))
61		ad = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
62	else
63	{
64		ad = ea;
65		size += sizeof(struct extendedAttrHeaderDesc);
66	}
67
68	offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
69		UDF_I_LENALLOC(inode);
70
71	/* TODO - Check for FreeEASpace */
72
73	if (loc & 0x01 && offset >= size)
74	{
75		struct extendedAttrHeaderDesc *eahd;
76		eahd = (struct extendedAttrHeaderDesc *)ea;
77
78		if (UDF_I_LENALLOC(inode))
79		{
80			memmove(&ad[size], ad, UDF_I_LENALLOC(inode));
81		}
82
83		if (UDF_I_LENEATTR(inode))
84		{
85			/* check checksum/crc */
86			if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
87				le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum)
88			{
89				return NULL;
90			}
91		}
92		else
93		{
94			size -= sizeof(struct extendedAttrHeaderDesc);
95			UDF_I_LENEATTR(inode) += sizeof(struct extendedAttrHeaderDesc);
96			eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
97			if (UDF_SB_UDFREV(inode->i_sb) >= 0x0200)
98				eahd->descTag.descVersion = cpu_to_le16(3);
99			else
100				eahd->descTag.descVersion = cpu_to_le16(2);
101			eahd->descTag.tagSerialNum = cpu_to_le16(UDF_SB_SERIALNUM(inode->i_sb));
102			eahd->descTag.tagLocation = cpu_to_le32(UDF_I_LOCATION(inode).logicalBlockNum);
103			eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
104			eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
105		}
106
107		offset = UDF_I_LENEATTR(inode);
108		if (type < 2048)
109		{
110			if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode))
111			{
112				uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
113				memmove(&ea[offset - aal + size],
114					&ea[aal], offset - aal);
115				offset -= aal;
116				eahd->appAttrLocation = cpu_to_le32(aal + size);
117			}
118			if (le32_to_cpu(eahd->impAttrLocation) < UDF_I_LENEATTR(inode))
119			{
120				uint32_t ial = le32_to_cpu(eahd->impAttrLocation);
121				memmove(&ea[offset - ial + size],
122					&ea[ial], offset - ial);
123				offset -= ial;
124				eahd->impAttrLocation = cpu_to_le32(ial + size);
125			}
126		}
127		else if (type < 65536)
128		{
129			if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode))
130			{
131				uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
132				memmove(&ea[offset - aal + size],
133					&ea[aal], offset - aal);
134				offset -= aal;
135				eahd->appAttrLocation = cpu_to_le32(aal + size);
136			}
137		}
138		/* rewrite CRC + checksum of eahd */
139		crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
140		eahd->descTag.descCRCLength = cpu_to_le16(crclen);
141		eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd + sizeof(tag), crclen, 0));
142		eahd->descTag.tagChecksum = 0;
143		for (i=0; i<16; i++)
144			if (i != 4)
145				eahd->descTag.tagChecksum += ((uint8_t *)&(eahd->descTag))[i];
146		UDF_I_LENEATTR(inode) += size;
147		return (struct genericFormat *)&ea[offset];
148	}
149	if (loc & 0x02)
150	{
151	}
152	return NULL;
153}
154
155struct genericFormat *
156udf_get_extendedattr(struct inode *inode, uint32_t type, uint8_t subtype)
157{
158	struct genericFormat *gaf;
159	uint8_t *ea = NULL;
160	uint32_t offset;
161
162	ea = UDF_I_DATA(inode);
163
164	if (UDF_I_LENEATTR(inode))
165	{
166		struct extendedAttrHeaderDesc *eahd;
167		eahd = (struct extendedAttrHeaderDesc *)ea;
168
169		/* check checksum/crc */
170		if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
171			le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum)
172		{
173			return NULL;
174		}
175
176		if (type < 2048)
177			offset = sizeof(struct extendedAttrHeaderDesc);
178		else if (type < 65536)
179			offset = le32_to_cpu(eahd->impAttrLocation);
180		else
181			offset = le32_to_cpu(eahd->appAttrLocation);
182
183		while (offset < UDF_I_LENEATTR(inode))
184		{
185			gaf = (struct genericFormat *)&ea[offset];
186			if (le32_to_cpu(gaf->attrType) == type && gaf->attrSubtype == subtype)
187				return gaf;
188			else
189				offset += le32_to_cpu(gaf->attrLength);
190		}
191	}
192	return NULL;
193}
194
195/*
196 * udf_read_tagged
197 *
198 * PURPOSE
199 *	Read the first block of a tagged descriptor.
200 *
201 * HISTORY
202 *	July 1, 1997 - Andrew E. Mileski
203 *	Written, tested, and released.
204 */
205struct buffer_head *
206udf_read_tagged(struct super_block *sb, uint32_t block, uint32_t location, uint16_t *ident)
207{
208	tag *tag_p;
209	struct buffer_head *bh = NULL;
210	register uint8_t checksum;
211	register int i;
212
213	/* Read the block */
214	if (block == 0xFFFFFFFF)
215		return NULL;
216
217	bh = udf_tread(sb, block + UDF_SB_SESSION(sb));
218	if (!bh)
219	{
220		udf_debug("block=%d, location=%d: read failed\n", block + UDF_SB_SESSION(sb), location);
221		return NULL;
222	}
223
224	tag_p = (tag *)(bh->b_data);
225
226	*ident = le16_to_cpu(tag_p->tagIdent);
227
228	if ( location != le32_to_cpu(tag_p->tagLocation) )
229	{
230		udf_debug("location mismatch block %u, tag %u != %u\n",
231			block + UDF_SB_SESSION(sb), le32_to_cpu(tag_p->tagLocation), location);
232		goto error_out;
233	}
234
235	/* Verify the tag checksum */
236	checksum = 0U;
237	for (i = 0; i < 4; i++)
238		checksum += (uint8_t)(bh->b_data[i]);
239	for (i = 5; i < 16; i++)
240		checksum += (uint8_t)(bh->b_data[i]);
241	if (checksum != tag_p->tagChecksum) {
242		printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
243		goto error_out;
244	}
245
246	/* Verify the tag version */
247	if (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
248		le16_to_cpu(tag_p->descVersion) != 0x0003U)
249	{
250		udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
251			le16_to_cpu(tag_p->descVersion), block);
252		goto error_out;
253	}
254
255	/* Verify the descriptor CRC */
256	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
257		le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
258			le16_to_cpu(tag_p->descCRCLength), 0))
259	{
260		return bh;
261	}
262	udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
263		block + UDF_SB_SESSION(sb), le16_to_cpu(tag_p->descCRC), le16_to_cpu(tag_p->descCRCLength));
264
265error_out:
266	brelse(bh);
267	return NULL;
268}
269
270struct buffer_head *
271udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc, uint32_t offset, uint16_t *ident)
272{
273	return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
274		loc.logicalBlockNum + offset, ident);
275}
276
277void udf_update_tag(char *data, int length)
278{
279	tag *tptr = (tag *)data;
280	int i;
281
282	length -= sizeof(tag);
283
284	tptr->tagChecksum = 0;
285	tptr->descCRCLength = cpu_to_le16(length);
286	tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
287
288	for (i=0; i<16; i++)
289		if (i != 4)
290			tptr->tagChecksum += (uint8_t)(data[i]);
291}
292
293void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
294	uint32_t loc, int length)
295{
296	tag *tptr = (tag *)data;
297	tptr->tagIdent = cpu_to_le16(ident);
298	tptr->descVersion = cpu_to_le16(version);
299	tptr->tagSerialNum = cpu_to_le16(snum);
300	tptr->tagLocation = cpu_to_le32(loc);
301	udf_update_tag(data, length);
302}
303