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 28 #include "udf_i.h" 29 #include "udf_sb.h" 30 31 struct buffer_head *udf_tgetblk(struct super_block *sb, int 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, int 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_ext.i_data; 56 if (iinfo->i_lenEAttr) { 57 ad = iinfo->i_ext.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(tag); 137 eahd->descTag.descCRCLength = cpu_to_le16(crclen); 138 eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd + 139 sizeof(tag), crclen, 0)); 140 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag); 141 iinfo->i_lenEAttr += size; 142 return (struct genericFormat *)&ea[offset]; 143 } 144 if (loc & 0x02) 145 ; 146 147 return NULL; 148 } 149 150 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type, 151 uint8_t subtype) 152 { 153 struct genericFormat *gaf; 154 uint8_t *ea = NULL; 155 uint32_t offset; 156 struct udf_inode_info *iinfo = UDF_I(inode); 157 158 ea = iinfo->i_ext.i_data; 159 160 if (iinfo->i_lenEAttr) { 161 struct extendedAttrHeaderDesc *eahd; 162 eahd = (struct extendedAttrHeaderDesc *)ea; 163 164 /* check checksum/crc */ 165 if (eahd->descTag.tagIdent != 166 cpu_to_le16(TAG_IDENT_EAHD) || 167 le32_to_cpu(eahd->descTag.tagLocation) != 168 iinfo->i_location.logicalBlockNum) 169 return NULL; 170 171 if (type < 2048) 172 offset = sizeof(struct extendedAttrHeaderDesc); 173 else if (type < 65536) 174 offset = le32_to_cpu(eahd->impAttrLocation); 175 else 176 offset = le32_to_cpu(eahd->appAttrLocation); 177 178 while (offset < iinfo->i_lenEAttr) { 179 gaf = (struct genericFormat *)&ea[offset]; 180 if (le32_to_cpu(gaf->attrType) == type && 181 gaf->attrSubtype == subtype) 182 return gaf; 183 else 184 offset += le32_to_cpu(gaf->attrLength); 185 } 186 } 187 188 return NULL; 189 } 190 191 /* 192 * udf_read_tagged 193 * 194 * PURPOSE 195 * Read the first block of a tagged descriptor. 196 * 197 * HISTORY 198 * July 1, 1997 - Andrew E. Mileski 199 * Written, tested, and released. 200 */ 201 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block, 202 uint32_t location, uint16_t *ident) 203 { 204 tag *tag_p; 205 struct buffer_head *bh = NULL; 206 207 /* Read the block */ 208 if (block == 0xFFFFFFFF) 209 return NULL; 210 211 bh = udf_tread(sb, block); 212 if (!bh) { 213 udf_debug("block=%d, location=%d: read failed\n", 214 block, location); 215 return NULL; 216 } 217 218 tag_p = (tag *)(bh->b_data); 219 220 *ident = le16_to_cpu(tag_p->tagIdent); 221 222 if (location != le32_to_cpu(tag_p->tagLocation)) { 223 udf_debug("location mismatch block %u, tag %u != %u\n", 224 block, le32_to_cpu(tag_p->tagLocation), location); 225 goto error_out; 226 } 227 228 /* Verify the tag checksum */ 229 if (udf_tag_checksum(tag_p) != tag_p->tagChecksum) { 230 printk(KERN_ERR "udf: tag checksum failed block %d\n", block); 231 goto error_out; 232 } 233 234 /* Verify the tag version */ 235 if (tag_p->descVersion != cpu_to_le16(0x0002U) && 236 tag_p->descVersion != cpu_to_le16(0x0003U)) { 237 udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n", 238 le16_to_cpu(tag_p->descVersion), block); 239 goto error_out; 240 } 241 242 /* Verify the descriptor CRC */ 243 if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize || 244 le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag), 245 le16_to_cpu(tag_p->descCRCLength), 0)) 246 return bh; 247 248 udf_debug("Crc failure block %d: crc = %d, crclen = %d\n", block, 249 le16_to_cpu(tag_p->descCRC), le16_to_cpu(tag_p->descCRCLength)); 250 251 error_out: 252 brelse(bh); 253 return NULL; 254 } 255 256 struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc, 257 uint32_t offset, uint16_t *ident) 258 { 259 return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset), 260 loc.logicalBlockNum + offset, ident); 261 } 262 263 void udf_update_tag(char *data, int length) 264 { 265 tag *tptr = (tag *)data; 266 length -= sizeof(tag); 267 268 tptr->descCRCLength = cpu_to_le16(length); 269 tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0)); 270 tptr->tagChecksum = udf_tag_checksum(tptr); 271 } 272 273 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum, 274 uint32_t loc, int length) 275 { 276 tag *tptr = (tag *)data; 277 tptr->tagIdent = cpu_to_le16(ident); 278 tptr->descVersion = cpu_to_le16(version); 279 tptr->tagSerialNum = cpu_to_le16(snum); 280 tptr->tagLocation = cpu_to_le32(loc); 281 udf_update_tag(data, length); 282 } 283 284 u8 udf_tag_checksum(const tag *t) 285 { 286 u8 *data = (u8 *)t; 287 u8 checksum = 0; 288 int i; 289 for (i = 0; i < sizeof(tag); ++i) 290 if (i != 4) /* position of checksum */ 291 checksum += data[i]; 292 return checksum; 293 } 294