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
32 struct buffer_head *udf_tgetblk(struct super_block *sb, int block)
33 {
34 if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
35 return sb_getblk(sb, udf_fixed_to_variable(block));
36 else
37 return sb_getblk(sb, block);
38 }
39
40 struct buffer_head *udf_tread(struct super_block *sb, int block)
41 {
42 if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
43 return sb_bread(sb, udf_fixed_to_variable(block));
44 else
45 return sb_bread(sb, block);
46 }
47
48 struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
49 uint32_t type, uint8_t loc)
50 {
51 uint8_t *ea = NULL, *ad = NULL;
52 int offset;
53 uint16_t crclen;
54 struct udf_inode_info *iinfo = UDF_I(inode);
55
56 ea = iinfo->i_ext.i_data;
57 if (iinfo->i_lenEAttr) {
58 ad = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
59 } else {
60 ad = ea;
61 size += sizeof(struct extendedAttrHeaderDesc);
62 }
63
64 offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
65 iinfo->i_lenAlloc;
66
67 /* TODO - Check for FreeEASpace */
68
69 if (loc & 0x01 && offset >= size) {
70 struct extendedAttrHeaderDesc *eahd;
71 eahd = (struct extendedAttrHeaderDesc *)ea;
72
73 if (iinfo->i_lenAlloc)
74 memmove(&ad[size], ad, iinfo->i_lenAlloc);
75
76 if (iinfo->i_lenEAttr) {
77 /* check checksum/crc */
78 if (eahd->descTag.tagIdent !=
79 cpu_to_le16(TAG_IDENT_EAHD) ||
80 le32_to_cpu(eahd->descTag.tagLocation) !=
81 iinfo->i_location.logicalBlockNum)
82 return NULL;
83 } else {
84 struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
85
86 size -= sizeof(struct extendedAttrHeaderDesc);
87 iinfo->i_lenEAttr +=
88 sizeof(struct extendedAttrHeaderDesc);
89 eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
90 if (sbi->s_udfrev >= 0x0200)
91 eahd->descTag.descVersion = cpu_to_le16(3);
92 else
93 eahd->descTag.descVersion = cpu_to_le16(2);
94 eahd->descTag.tagSerialNum =
95 cpu_to_le16(sbi->s_serial_number);
96 eahd->descTag.tagLocation = cpu_to_le32(
97 iinfo->i_location.logicalBlockNum);
98 eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
99 eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
100 }
101
102 offset = iinfo->i_lenEAttr;
103 if (type < 2048) {
104 if (le32_to_cpu(eahd->appAttrLocation) <
105 iinfo->i_lenEAttr) {
106 uint32_t aal =
107 le32_to_cpu(eahd->appAttrLocation);
108 memmove(&ea[offset - aal + size],
109 &ea[aal], offset - aal);
110 offset -= aal;
111 eahd->appAttrLocation =
112 cpu_to_le32(aal + size);
113 }
114 if (le32_to_cpu(eahd->impAttrLocation) <
115 iinfo->i_lenEAttr) {
116 uint32_t ial =
117 le32_to_cpu(eahd->impAttrLocation);
118 memmove(&ea[offset - ial + size],
119 &ea[ial], offset - ial);
120 offset -= ial;
121 eahd->impAttrLocation =
122 cpu_to_le32(ial + size);
123 }
124 } else if (type < 65536) {
125 if (le32_to_cpu(eahd->appAttrLocation) <
126 iinfo->i_lenEAttr) {
127 uint32_t aal =
128 le32_to_cpu(eahd->appAttrLocation);
129 memmove(&ea[offset - aal + size],
130 &ea[aal], offset - aal);
131 offset -= aal;
132 eahd->appAttrLocation =
133 cpu_to_le32(aal + size);
134 }
135 }
136 /* rewrite CRC + checksum of eahd */
137 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
138 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
139 eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
140 sizeof(tag), crclen, 0));
141 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
142 iinfo->i_lenEAttr += size;
143 return (struct genericFormat *)&ea[offset];
144 }
145 if (loc & 0x02)
146 ;
147
148 return NULL;
149 }
150
151 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
152 uint8_t subtype)
153 {
154 struct genericFormat *gaf;
155 uint8_t *ea = NULL;
156 uint32_t offset;
157 struct udf_inode_info *iinfo = UDF_I(inode);
158
159 ea = iinfo->i_ext.i_data;
160
161 if (iinfo->i_lenEAttr) {
162 struct extendedAttrHeaderDesc *eahd;
163 eahd = (struct extendedAttrHeaderDesc *)ea;
164
165 /* check checksum/crc */
166 if (eahd->descTag.tagIdent !=
167 cpu_to_le16(TAG_IDENT_EAHD) ||
168 le32_to_cpu(eahd->descTag.tagLocation) !=
169 iinfo->i_location.logicalBlockNum)
170 return NULL;
171
172 if (type < 2048)
173 offset = sizeof(struct extendedAttrHeaderDesc);
174 else if (type < 65536)
175 offset = le32_to_cpu(eahd->impAttrLocation);
176 else
177 offset = le32_to_cpu(eahd->appAttrLocation);
178
179 while (offset < iinfo->i_lenEAttr) {
180 gaf = (struct genericFormat *)&ea[offset];
181 if (le32_to_cpu(gaf->attrType) == type &&
182 gaf->attrSubtype == subtype)
183 return gaf;
184 else
185 offset += le32_to_cpu(gaf->attrLength);
186 }
187 }
188
189 return NULL;
190 }
191
192 /*
193 * udf_read_tagged
194 *
195 * PURPOSE
196 * Read the first block of a tagged descriptor.
197 *
198 * HISTORY
199 * July 1, 1997 - Andrew E. Mileski
200 * Written, tested, and released.
201 */
202 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
203 uint32_t location, uint16_t *ident)
204 {
205 tag *tag_p;
206 struct buffer_head *bh = NULL;
207 struct udf_sb_info *sbi = UDF_SB(sb);
208
209 /* Read the block */
210 if (block == 0xFFFFFFFF)
211 return NULL;
212
213 bh = udf_tread(sb, block + sbi->s_session);
214 if (!bh) {
215 udf_debug("block=%d, location=%d: read failed\n",
216 block + sbi->s_session, location);
217 return NULL;
218 }
219
220 tag_p = (tag *)(bh->b_data);
221
222 *ident = le16_to_cpu(tag_p->tagIdent);
223
224 if (location != le32_to_cpu(tag_p->tagLocation)) {
225 udf_debug("location mismatch block %u, tag %u != %u\n",
226 block + sbi->s_session,
227 le32_to_cpu(tag_p->tagLocation), location);
228 goto error_out;
229 }
230
231 /* Verify the tag checksum */
232 if (udf_tag_checksum(tag_p) != tag_p->tagChecksum) {
233 printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
234 goto error_out;
235 }
236
237 /* Verify the tag version */
238 if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
239 tag_p->descVersion != cpu_to_le16(0x0003U)) {
240 udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
241 le16_to_cpu(tag_p->descVersion), block);
242 goto error_out;
243 }
244
245 /* Verify the descriptor CRC */
246 if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
247 le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
248 le16_to_cpu(tag_p->descCRCLength), 0))
249 return bh;
250
251 udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
252 block + sbi->s_session, le16_to_cpu(tag_p->descCRC),
253 le16_to_cpu(tag_p->descCRCLength));
254
255 error_out:
256 brelse(bh);
257 return NULL;
258 }
259
260 struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc,
261 uint32_t offset, uint16_t *ident)
262 {
263 return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
264 loc.logicalBlockNum + offset, ident);
265 }
266
267 void udf_update_tag(char *data, int length)
268 {
269 tag *tptr = (tag *)data;
270 length -= sizeof(tag);
271
272 tptr->descCRCLength = cpu_to_le16(length);
273 tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
274 tptr->tagChecksum = udf_tag_checksum(tptr);
275 }
276
277 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
278 uint32_t loc, int length)
279 {
280 tag *tptr = (tag *)data;
281 tptr->tagIdent = cpu_to_le16(ident);
282 tptr->descVersion = cpu_to_le16(version);
283 tptr->tagSerialNum = cpu_to_le16(snum);
284 tptr->tagLocation = cpu_to_le32(loc);
285 udf_update_tag(data, length);
286 }
287
288 u8 udf_tag_checksum(const tag *t)
289 {
290 u8 *data = (u8 *)t;
291 u8 checksum = 0;
292 int i;
293 for (i = 0; i < sizeof(tag); ++i)
294 if (i != 4) /* position of checksum */
295 checksum += data[i];
296 return checksum;
297 }
298
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