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/buffer_head.h>
27 #include <linux/crc-itu-t.h>
28
29 #include "udf_i.h"
30 #include "udf_sb.h"
31
udf_tgetblk(struct super_block * sb,int block)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
udf_tread(struct super_block * sb,int block)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
udf_add_extendedattr(struct inode * inode,uint32_t size,uint32_t type,uint8_t loc)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(struct tag);
138 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
139 eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
140 sizeof(struct tag), crclen));
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
udf_get_extendedattr(struct inode * inode,uint32_t type,uint8_t subtype)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 */
udf_read_tagged(struct super_block * sb,uint32_t block,uint32_t location,uint16_t * ident)202 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
203 uint32_t location, uint16_t *ident)
204 {
205 struct tag *tag_p;
206 struct buffer_head *bh = NULL;
207 u8 checksum;
208
209 /* Read the block */
210 if (block == 0xFFFFFFFF)
211 return NULL;
212
213 bh = udf_tread(sb, block);
214 if (!bh) {
215 udf_err(sb, "read failed, block=%u, location=%d\n",
216 block, location);
217 return NULL;
218 }
219
220 tag_p = (struct 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, le32_to_cpu(tag_p->tagLocation), location);
227 goto error_out;
228 }
229
230 /* Verify the tag checksum */
231 checksum = udf_tag_checksum(tag_p);
232 if (checksum != tag_p->tagChecksum) {
233 udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
234 block, checksum, tag_p->tagChecksum);
235 goto error_out;
236 }
237
238 /* Verify the tag version */
239 if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
240 tag_p->descVersion != cpu_to_le16(0x0003U)) {
241 udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
242 le16_to_cpu(tag_p->descVersion), block);
243 goto error_out;
244 }
245
246 /* Verify the descriptor CRC */
247 if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
248 le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
249 bh->b_data + sizeof(struct tag),
250 le16_to_cpu(tag_p->descCRCLength)))
251 return bh;
252
253 udf_debug("Crc failure block %d: crc = %d, crclen = %d\n", block,
254 le16_to_cpu(tag_p->descCRC),
255 le16_to_cpu(tag_p->descCRCLength));
256 error_out:
257 brelse(bh);
258 return NULL;
259 }
260
udf_read_ptagged(struct super_block * sb,struct kernel_lb_addr * loc,uint32_t offset,uint16_t * ident)261 struct buffer_head *udf_read_ptagged(struct super_block *sb,
262 struct kernel_lb_addr *loc,
263 uint32_t offset, uint16_t *ident)
264 {
265 return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
266 loc->logicalBlockNum + offset, ident);
267 }
268
udf_update_tag(char * data,int length)269 void udf_update_tag(char *data, int length)
270 {
271 struct tag *tptr = (struct tag *)data;
272 length -= sizeof(struct tag);
273
274 tptr->descCRCLength = cpu_to_le16(length);
275 tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
276 tptr->tagChecksum = udf_tag_checksum(tptr);
277 }
278
udf_new_tag(char * data,uint16_t ident,uint16_t version,uint16_t snum,uint32_t loc,int length)279 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
280 uint32_t loc, int length)
281 {
282 struct tag *tptr = (struct tag *)data;
283 tptr->tagIdent = cpu_to_le16(ident);
284 tptr->descVersion = cpu_to_le16(version);
285 tptr->tagSerialNum = cpu_to_le16(snum);
286 tptr->tagLocation = cpu_to_le32(loc);
287 udf_update_tag(data, length);
288 }
289
udf_tag_checksum(const struct tag * t)290 u8 udf_tag_checksum(const struct tag *t)
291 {
292 u8 *data = (u8 *)t;
293 u8 checksum = 0;
294 int i;
295 for (i = 0; i < sizeof(struct tag); ++i)
296 if (i != 4) /* position of checksum */
297 checksum += data[i];
298 return checksum;
299 }
300