1614d308d0f06039ee0a4b27e0e9e9f93c44e8da
[releases.git] / misc.c
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/crc-itu-t.h>
27
28 #include "udf_i.h"
29 #include "udf_sb.h"
30
31 struct buffer_head *udf_tgetblk(struct super_block *sb, udf_pblk_t block)
32 {
33         if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
34                 return sb_getblk(sb, udf_fixed_to_variable(block));
35         else
36                 return sb_getblk(sb, block);
37 }
38
39 struct buffer_head *udf_tread(struct super_block *sb, udf_pblk_t block)
40 {
41         if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
42                 return sb_bread(sb, udf_fixed_to_variable(block));
43         else
44                 return sb_bread(sb, block);
45 }
46
47 struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
48                                            uint32_t type, uint8_t loc)
49 {
50         uint8_t *ea = NULL, *ad = NULL;
51         int offset;
52         uint16_t crclen;
53         struct udf_inode_info *iinfo = UDF_I(inode);
54
55         ea = iinfo->i_data;
56         if (iinfo->i_lenEAttr) {
57                 ad = iinfo->i_data + iinfo->i_lenEAttr;
58         } else {
59                 ad = ea;
60                 size += sizeof(struct extendedAttrHeaderDesc);
61         }
62
63         offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
64                 iinfo->i_lenAlloc;
65
66         /* TODO - Check for FreeEASpace */
67
68         if (loc & 0x01 && offset >= size) {
69                 struct extendedAttrHeaderDesc *eahd;
70                 eahd = (struct extendedAttrHeaderDesc *)ea;
71
72                 if (iinfo->i_lenAlloc)
73                         memmove(&ad[size], ad, iinfo->i_lenAlloc);
74
75                 if (iinfo->i_lenEAttr) {
76                         /* check checksum/crc */
77                         if (eahd->descTag.tagIdent !=
78                                         cpu_to_le16(TAG_IDENT_EAHD) ||
79                             le32_to_cpu(eahd->descTag.tagLocation) !=
80                                         iinfo->i_location.logicalBlockNum)
81                                 return NULL;
82                 } else {
83                         struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
84
85                         size -= sizeof(struct extendedAttrHeaderDesc);
86                         iinfo->i_lenEAttr +=
87                                 sizeof(struct extendedAttrHeaderDesc);
88                         eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
89                         if (sbi->s_udfrev >= 0x0200)
90                                 eahd->descTag.descVersion = cpu_to_le16(3);
91                         else
92                                 eahd->descTag.descVersion = cpu_to_le16(2);
93                         eahd->descTag.tagSerialNum =
94                                         cpu_to_le16(sbi->s_serial_number);
95                         eahd->descTag.tagLocation = cpu_to_le32(
96                                         iinfo->i_location.logicalBlockNum);
97                         eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
98                         eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
99                 }
100
101                 offset = iinfo->i_lenEAttr;
102                 if (type < 2048) {
103                         if (le32_to_cpu(eahd->appAttrLocation) <
104                                         iinfo->i_lenEAttr) {
105                                 uint32_t aal =
106                                         le32_to_cpu(eahd->appAttrLocation);
107                                 memmove(&ea[offset - aal + size],
108                                         &ea[aal], offset - aal);
109                                 offset -= aal;
110                                 eahd->appAttrLocation =
111                                                 cpu_to_le32(aal + size);
112                         }
113                         if (le32_to_cpu(eahd->impAttrLocation) <
114                                         iinfo->i_lenEAttr) {
115                                 uint32_t ial =
116                                         le32_to_cpu(eahd->impAttrLocation);
117                                 memmove(&ea[offset - ial + size],
118                                         &ea[ial], offset - ial);
119                                 offset -= ial;
120                                 eahd->impAttrLocation =
121                                                 cpu_to_le32(ial + size);
122                         }
123                 } else if (type < 65536) {
124                         if (le32_to_cpu(eahd->appAttrLocation) <
125                                         iinfo->i_lenEAttr) {
126                                 uint32_t aal =
127                                         le32_to_cpu(eahd->appAttrLocation);
128                                 memmove(&ea[offset - aal + size],
129                                         &ea[aal], offset - aal);
130                                 offset -= aal;
131                                 eahd->appAttrLocation =
132                                                 cpu_to_le32(aal + size);
133                         }
134                 }
135                 /* rewrite CRC + checksum of eahd */
136                 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(struct tag);
137                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
138                 eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
139                                                 sizeof(struct tag), crclen));
140                 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
141                 iinfo->i_lenEAttr += size;
142                 return (struct genericFormat *)&ea[offset];
143         }
144
145         return NULL;
146 }
147
148 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
149                                            uint8_t subtype)
150 {
151         struct genericFormat *gaf;
152         uint8_t *ea = NULL;
153         uint32_t offset;
154         struct udf_inode_info *iinfo = UDF_I(inode);
155
156         ea = iinfo->i_data;
157
158         if (iinfo->i_lenEAttr) {
159                 struct extendedAttrHeaderDesc *eahd;
160                 eahd = (struct extendedAttrHeaderDesc *)ea;
161
162                 /* check checksum/crc */
163                 if (eahd->descTag.tagIdent !=
164                                 cpu_to_le16(TAG_IDENT_EAHD) ||
165                     le32_to_cpu(eahd->descTag.tagLocation) !=
166                                 iinfo->i_location.logicalBlockNum)
167                         return NULL;
168
169                 if (type < 2048)
170                         offset = sizeof(struct extendedAttrHeaderDesc);
171                 else if (type < 65536)
172                         offset = le32_to_cpu(eahd->impAttrLocation);
173                 else
174                         offset = le32_to_cpu(eahd->appAttrLocation);
175
176                 while (offset + sizeof(*gaf) < iinfo->i_lenEAttr) {
177                         uint32_t attrLength;
178
179                         gaf = (struct genericFormat *)&ea[offset];
180                         attrLength = le32_to_cpu(gaf->attrLength);
181
182                         /* Detect undersized elements and buffer overflows */
183                         if ((attrLength < sizeof(*gaf)) ||
184                             (attrLength > (iinfo->i_lenEAttr - offset)))
185                                 break;
186
187                         if (le32_to_cpu(gaf->attrType) == type &&
188                                         gaf->attrSubtype == subtype)
189                                 return gaf;
190                         else
191                                 offset += attrLength;
192                 }
193         }
194
195         return NULL;
196 }
197
198 /*
199  * udf_read_tagged
200  *
201  * PURPOSE
202  *      Read the first block of a tagged descriptor.
203  *
204  * HISTORY
205  *      July 1, 1997 - Andrew E. Mileski
206  *      Written, tested, and released.
207  */
208 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
209                                     uint32_t location, uint16_t *ident)
210 {
211         struct tag *tag_p;
212         struct buffer_head *bh = NULL;
213         u8 checksum;
214
215         /* Read the block */
216         if (block == 0xFFFFFFFF)
217                 return NULL;
218
219         bh = udf_tread(sb, block);
220         if (!bh) {
221                 udf_err(sb, "read failed, block=%u, location=%u\n",
222                         block, location);
223                 return NULL;
224         }
225
226         tag_p = (struct tag *)(bh->b_data);
227
228         *ident = le16_to_cpu(tag_p->tagIdent);
229
230         if (location != le32_to_cpu(tag_p->tagLocation)) {
231                 udf_debug("location mismatch block %u, tag %u != %u\n",
232                           block, le32_to_cpu(tag_p->tagLocation), location);
233                 goto error_out;
234         }
235
236         /* Verify the tag checksum */
237         checksum = udf_tag_checksum(tag_p);
238         if (checksum != tag_p->tagChecksum) {
239                 udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
240                         block, checksum, tag_p->tagChecksum);
241                 goto error_out;
242         }
243
244         /* Verify the tag version */
245         if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
246             tag_p->descVersion != cpu_to_le16(0x0003U)) {
247                 udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
248                         le16_to_cpu(tag_p->descVersion), block);
249                 goto error_out;
250         }
251
252         /* Verify the descriptor CRC */
253         if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
254             le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
255                                         bh->b_data + sizeof(struct tag),
256                                         le16_to_cpu(tag_p->descCRCLength)))
257                 return bh;
258
259         udf_debug("Crc failure block %u: crc = %u, crclen = %u\n", block,
260                   le16_to_cpu(tag_p->descCRC),
261                   le16_to_cpu(tag_p->descCRCLength));
262 error_out:
263         brelse(bh);
264         return NULL;
265 }
266
267 struct buffer_head *udf_read_ptagged(struct super_block *sb,
268                                      struct kernel_lb_addr *loc,
269                                      uint32_t offset, uint16_t *ident)
270 {
271         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
272                                loc->logicalBlockNum + offset, ident);
273 }
274
275 void udf_update_tag(char *data, int length)
276 {
277         struct tag *tptr = (struct tag *)data;
278         length -= sizeof(struct tag);
279
280         tptr->descCRCLength = cpu_to_le16(length);
281         tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
282         tptr->tagChecksum = udf_tag_checksum(tptr);
283 }
284
285 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
286                  uint32_t loc, int length)
287 {
288         struct tag *tptr = (struct tag *)data;
289         tptr->tagIdent = cpu_to_le16(ident);
290         tptr->descVersion = cpu_to_le16(version);
291         tptr->tagSerialNum = cpu_to_le16(snum);
292         tptr->tagLocation = cpu_to_le32(loc);
293         udf_update_tag(data, length);
294 }
295
296 u8 udf_tag_checksum(const struct tag *t)
297 {
298         u8 *data = (u8 *)t;
299         u8 checksum = 0;
300         int i;
301         for (i = 0; i < sizeof(struct tag); ++i)
302                 if (i != 4) /* position of checksum */
303                         checksum += data[i];
304         return checksum;
305 }