Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/udf/misc.c
Version:
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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 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 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 } 150 151 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 */ 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 } 260 261 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 } 268 269 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 } 278 279 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 } 289 290 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 }
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