fs/udf/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/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
 208         /* Read the block */
 209         if (block == 0xFFFFFFFF)
 210                 return NULL;
 211
 212         bh = udf_tread(sb, block);
 213         if (!bh) {
 214                 udf_debug("block=%d, location=%d: read failed\n",
 215                           block, location);
 216                 return NULL;
 217         }
 218
 219         tag_p = (struct tag *)(bh->b_data);
 220
 221         *ident = le16_to_cpu(tag_p->tagIdent);
 222
 223         if (location != le32_to_cpu(tag_p->tagLocation)) {
 224                 udf_debug("location mismatch block %u, tag %u != %u\n",
 225                           block, le32_to_cpu(tag_p->tagLocation), location);
 226                 goto error_out;
 227         }
 228
 229         /* Verify the tag checksum */
 230         if (udf_tag_checksum(tag_p) != tag_p->tagChecksum) {
 231                 printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
 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_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\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 %d: crc = %d, crclen = %d\n", block,
 251             le16_to_cpu(tag_p->descCRC), le16_to_cpu(tag_p->descCRCLength));
 252
 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 }