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_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(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_ext.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 < iinfo->i_lenEAttr) { 177 gaf = (struct genericFormat *)&ea[offset]; 178 if (le32_to_cpu(gaf->attrType) == type && 179 gaf->attrSubtype == subtype) 180 return gaf; 181 else 182 offset += le32_to_cpu(gaf->attrLength); 183 } 184 } 185 186 return NULL; 187 } 188 189 /* 190 * udf_read_tagged 191 * 192 * PURPOSE 193 * Read the first block of a tagged descriptor. 194 * 195 * HISTORY 196 * July 1, 1997 - Andrew E. Mileski 197 * Written, tested, and released. 198 */ 199 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block, 200 uint32_t location, uint16_t *ident) 201 { 202 struct tag *tag_p; 203 struct buffer_head *bh = NULL; 204 u8 checksum; 205 206 /* Read the block */ 207 if (block == 0xFFFFFFFF) 208 return NULL; 209 210 bh = udf_tread(sb, block); 211 if (!bh) { 212 udf_err(sb, "read failed, block=%u, location=%u\n", 213 block, location); 214 return NULL; 215 } 216 217 tag_p = (struct tag *)(bh->b_data); 218 219 *ident = le16_to_cpu(tag_p->tagIdent); 220 221 if (location != le32_to_cpu(tag_p->tagLocation)) { 222 udf_debug("location mismatch block %u, tag %u != %u\n", 223 block, le32_to_cpu(tag_p->tagLocation), location); 224 goto error_out; 225 } 226 227 /* Verify the tag checksum */ 228 checksum = udf_tag_checksum(tag_p); 229 if (checksum != tag_p->tagChecksum) { 230 udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n", 231 block, checksum, tag_p->tagChecksum); 232 goto error_out; 233 } 234 235 /* Verify the tag version */ 236 if (tag_p->descVersion != cpu_to_le16(0x0002U) && 237 tag_p->descVersion != cpu_to_le16(0x0003U)) { 238 udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n", 239 le16_to_cpu(tag_p->descVersion), block); 240 goto error_out; 241 } 242 243 /* Verify the descriptor CRC */ 244 if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize || 245 le16_to_cpu(tag_p->descCRC) == crc_itu_t(0, 246 bh->b_data + sizeof(struct tag), 247 le16_to_cpu(tag_p->descCRCLength))) 248 return bh; 249 250 udf_debug("Crc failure block %u: crc = %u, crclen = %u\n", block, 251 le16_to_cpu(tag_p->descCRC), 252 le16_to_cpu(tag_p->descCRCLength)); 253 error_out: 254 brelse(bh); 255 return NULL; 256 } 257 258 struct buffer_head *udf_read_ptagged(struct super_block *sb, 259 struct kernel_lb_addr *loc, 260 uint32_t offset, uint16_t *ident) 261 { 262 return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset), 263 loc->logicalBlockNum + offset, ident); 264 } 265 266 void udf_update_tag(char *data, int length) 267 { 268 struct tag *tptr = (struct tag *)data; 269 length -= sizeof(struct tag); 270 271 tptr->descCRCLength = cpu_to_le16(length); 272 tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length)); 273 tptr->tagChecksum = udf_tag_checksum(tptr); 274 } 275 276 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum, 277 uint32_t loc, int length) 278 { 279 struct tag *tptr = (struct tag *)data; 280 tptr->tagIdent = cpu_to_le16(ident); 281 tptr->descVersion = cpu_to_le16(version); 282 tptr->tagSerialNum = cpu_to_le16(snum); 283 tptr->tagLocation = cpu_to_le32(loc); 284 udf_update_tag(data, length); 285 } 286 287 u8 udf_tag_checksum(const struct tag *t) 288 { 289 u8 *data = (u8 *)t; 290 u8 checksum = 0; 291 int i; 292 for (i = 0; i < sizeof(struct tag); ++i) 293 if (i != 4) /* position of checksum */ 294 checksum += data[i]; 295 return checksum; 296 } 297