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 int i; 55 56 ea = UDF_I_DATA(inode); 57 if (UDF_I_LENEATTR(inode)) { 58 ad = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode); 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 UDF_I_LENALLOC(inode); 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 (UDF_I_LENALLOC(inode)) 74 memmove(&ad[size], ad, UDF_I_LENALLOC(inode)); 75 76 if (UDF_I_LENEATTR(inode)) { 77 /* check checksum/crc */ 78 if (le16_to_cpu(eahd->descTag.tagIdent) != 79 TAG_IDENT_EAHD || 80 le32_to_cpu(eahd->descTag.tagLocation) != 81 UDF_I_LOCATION(inode).logicalBlockNum) 82 return NULL; 83 } else { 84 struct udf_sb_info *sbi = UDF_SB(inode->i_sb); 85 86 size -= sizeof(struct extendedAttrHeaderDesc); 87 UDF_I_LENEATTR(inode) += 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 UDF_I_LOCATION(inode).logicalBlockNum); 98 eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF); 99 eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF); 100 } 101 102 offset = UDF_I_LENEATTR(inode); 103 if (type < 2048) { 104 if (le32_to_cpu(eahd->appAttrLocation) < 105 UDF_I_LENEATTR(inode)) { 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 UDF_I_LENEATTR(inode)) { 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 UDF_I_LENEATTR(inode)) { 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 = 0; 142 for (i = 0; i < 16; i++) 143 if (i != 4) 144 eahd->descTag.tagChecksum += 145 ((uint8_t *)&(eahd->descTag))[i]; 146 UDF_I_LENEATTR(inode) += size; 147 return (struct genericFormat *)&ea[offset]; 148 } 149 if (loc & 0x02) 150 ; 151 152 return NULL; 153 } 154 155 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type, 156 uint8_t subtype) 157 { 158 struct genericFormat *gaf; 159 uint8_t *ea = NULL; 160 uint32_t offset; 161 162 ea = UDF_I_DATA(inode); 163 164 if (UDF_I_LENEATTR(inode)) { 165 struct extendedAttrHeaderDesc *eahd; 166 eahd = (struct extendedAttrHeaderDesc *)ea; 167 168 /* check checksum/crc */ 169 if (le16_to_cpu(eahd->descTag.tagIdent) != 170 TAG_IDENT_EAHD || 171 le32_to_cpu(eahd->descTag.tagLocation) != 172 UDF_I_LOCATION(inode).logicalBlockNum) 173 return NULL; 174 175 if (type < 2048) 176 offset = sizeof(struct extendedAttrHeaderDesc); 177 else if (type < 65536) 178 offset = le32_to_cpu(eahd->impAttrLocation); 179 else 180 offset = le32_to_cpu(eahd->appAttrLocation); 181 182 while (offset < UDF_I_LENEATTR(inode)) { 183 gaf = (struct genericFormat *)&ea[offset]; 184 if (le32_to_cpu(gaf->attrType) == type && 185 gaf->attrSubtype == subtype) 186 return gaf; 187 else 188 offset += le32_to_cpu(gaf->attrLength); 189 } 190 } 191 192 return NULL; 193 } 194 195 /* 196 * udf_read_tagged 197 * 198 * PURPOSE 199 * Read the first block of a tagged descriptor. 200 * 201 * HISTORY 202 * July 1, 1997 - Andrew E. Mileski 203 * Written, tested, and released. 204 */ 205 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block, 206 uint32_t location, uint16_t *ident) 207 { 208 tag *tag_p; 209 struct buffer_head *bh = NULL; 210 register uint8_t checksum; 211 register int i; 212 struct udf_sb_info *sbi = UDF_SB(sb); 213 214 /* Read the block */ 215 if (block == 0xFFFFFFFF) 216 return NULL; 217 218 bh = udf_tread(sb, block + sbi->s_session); 219 if (!bh) { 220 udf_debug("block=%d, location=%d: read failed\n", 221 block + sbi->s_session, location); 222 return NULL; 223 } 224 225 tag_p = (tag *)(bh->b_data); 226 227 *ident = le16_to_cpu(tag_p->tagIdent); 228 229 if (location != le32_to_cpu(tag_p->tagLocation)) { 230 udf_debug("location mismatch block %u, tag %u != %u\n", 231 block + sbi->s_session, 232 le32_to_cpu(tag_p->tagLocation), location); 233 goto error_out; 234 } 235 236 /* Verify the tag checksum */ 237 checksum = 0U; 238 for (i = 0; i < 4; i++) 239 checksum += (uint8_t)(bh->b_data[i]); 240 for (i = 5; i < 16; i++) 241 checksum += (uint8_t)(bh->b_data[i]); 242 if (checksum != tag_p->tagChecksum) { 243 printk(KERN_ERR "udf: tag checksum failed block %d\n", block); 244 goto error_out; 245 } 246 247 /* Verify the tag version */ 248 if (le16_to_cpu(tag_p->descVersion) != 0x0002U && 249 le16_to_cpu(tag_p->descVersion) != 0x0003U) { 250 udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n", 251 le16_to_cpu(tag_p->descVersion), block); 252 goto error_out; 253 } 254 255 /* Verify the descriptor CRC */ 256 if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize || 257 le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag), 258 le16_to_cpu(tag_p->descCRCLength), 0)) 259 return bh; 260 261 udf_debug("Crc failure block %d: crc = %d, crclen = %d\n", 262 block + sbi->s_session, le16_to_cpu(tag_p->descCRC), 263 le16_to_cpu(tag_p->descCRCLength)); 264 265 error_out: 266 brelse(bh); 267 return NULL; 268 } 269 270 struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc, 271 uint32_t offset, uint16_t *ident) 272 { 273 return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset), 274 loc.logicalBlockNum + offset, ident); 275 } 276 277 void udf_update_tag(char *data, int length) 278 { 279 tag *tptr = (tag *)data; 280 int i; 281 282 length -= sizeof(tag); 283 284 tptr->tagChecksum = 0; 285 tptr->descCRCLength = cpu_to_le16(length); 286 tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0)); 287 288 for (i = 0; i < 16; i++) 289 if (i != 4) 290 tptr->tagChecksum += (uint8_t)(data[i]); 291 } 292 293 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum, 294 uint32_t loc, int length) 295 { 296 tag *tptr = (tag *)data; 297 tptr->tagIdent = cpu_to_le16(ident); 298 tptr->descVersion = cpu_to_le16(version); 299 tptr->tagSerialNum = cpu_to_le16(snum); 300 tptr->tagLocation = cpu_to_le32(loc); 301 udf_update_tag(data, length); 302 } 303