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/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
  77                 if (UDF_I_LENEATTR(inode)) {
  78                         /* check checksum/crc */
  79                         if (le16_to_cpu(eahd->descTag.tagIdent) !=
  80                             TAG_IDENT_EAHD
  81                             || le32_to_cpu(eahd->descTag.tagLocation) !=
  82                             UDF_I_LOCATION(inode).logicalBlockNum) {
  83                                 return NULL;
  84                         }
  85                 } else {
  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 (UDF_SB_UDFREV(inode->i_sb) >= 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(UDF_SB_SERIALNUM(inode->i_sb));
  96                         eahd->descTag.tagLocation =
  97                             cpu_to_le32(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], &ea[aal],
 109                                         offset - aal);
 110                                 offset -= aal;
 111                                 eahd->appAttrLocation = cpu_to_le32(aal + size);
 112                         }
 113                         if (le32_to_cpu(eahd->impAttrLocation) <
 114                             UDF_I_LENEATTR(inode)) {
 115                                 uint32_t ial =
 116                                     le32_to_cpu(eahd->impAttrLocation);
 117                                 memmove(&ea[offset - ial + size], &ea[ial],
 118                                         offset - ial);
 119                                 offset -= ial;
 120                                 eahd->impAttrLocation = cpu_to_le32(ial + size);
 121                         }
 122                 } else if (type < 65536) {
 123                         if (le32_to_cpu(eahd->appAttrLocation) <
 124                             UDF_I_LENEATTR(inode)) {
 125                                 uint32_t aal =
 126                                     le32_to_cpu(eahd->appAttrLocation);
 127                                 memmove(&ea[offset - aal + size], &ea[aal],
 128                                         offset - aal);
 129                                 offset -= aal;
 130                                 eahd->appAttrLocation = cpu_to_le32(aal + size);
 131                         }
 132                 }
 133                 /* rewrite CRC + checksum of eahd */
 134                 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
 135                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
 136                 eahd->descTag.descCRC =
 137                     cpu_to_le16(udf_crc((char *)eahd + sizeof(tag), crclen, 0));
 138                 eahd->descTag.tagChecksum = 0;
 139                 for (i = 0; i < 16; i++)
 140                         if (i != 4)
 141                                 eahd->descTag.tagChecksum +=
 142                                     ((uint8_t *) & (eahd->descTag))[i];
 143                 UDF_I_LENEATTR(inode) += size;
 144                 return (struct genericFormat *)&ea[offset];
 145         }
 146         if (loc & 0x02) {
 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
 158         ea = UDF_I_DATA(inode);
 159
 160         if (UDF_I_LENEATTR(inode)) {
 161                 struct extendedAttrHeaderDesc *eahd;
 162                 eahd = (struct extendedAttrHeaderDesc *)ea;
 163
 164                 /* check checksum/crc */
 165                 if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
 166                     le32_to_cpu(eahd->descTag.tagLocation) !=
 167                     UDF_I_LOCATION(inode).logicalBlockNum) {
 168                         return NULL;
 169                 }
 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 < UDF_I_LENEATTR(inode)) {
 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         return NULL;
 188 }
 189
 190 /*
 191  * udf_read_tagged
 192  *
 193  * PURPOSE
 194  *      Read the first block of a tagged descriptor.
 195  *
 196  * HISTORY
 197  *      July 1, 1997 - Andrew E. Mileski
 198  *      Written, tested, and released.
 199  */
 200 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
 201                                     uint32_t location, uint16_t * ident)
 202 {
 203         tag *tag_p;
 204         struct buffer_head *bh = NULL;
 205         register uint8_t checksum;
 206         register int i;
 207
 208         /* Read the block */
 209         if (block == 0xFFFFFFFF)
 210                 return NULL;
 211
 212         bh = udf_tread(sb, block + UDF_SB_SESSION(sb));
 213         if (!bh) {
 214                 udf_debug("block=%d, location=%d: read failed\n",
 215                           block + UDF_SB_SESSION(sb), location);
 216                 return NULL;
 217         }
 218
 219         tag_p = (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 + UDF_SB_SESSION(sb),
 226                           le32_to_cpu(tag_p->tagLocation), location);
 227                 goto error_out;
 228         }
 229
 230         /* Verify the tag checksum */
 231         checksum = 0U;
 232         for (i = 0; i < 4; i++)
 233                 checksum += (uint8_t) (bh->b_data[i]);
 234         for (i = 5; i < 16; i++)
 235                 checksum += (uint8_t) (bh->b_data[i]);
 236         if (checksum != tag_p->tagChecksum) {
 237                 printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
 238                 goto error_out;
 239         }
 240
 241         /* Verify the tag version */
 242         if (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
 243             le16_to_cpu(tag_p->descVersion) != 0x0003U) {
 244                 udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
 245                           le16_to_cpu(tag_p->descVersion), block);
 246                 goto error_out;
 247         }
 248
 249         /* Verify the descriptor CRC */
 250         if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
 251             le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
 252                                                    le16_to_cpu(tag_p->
 253                                                                descCRCLength),
 254                                                    0)) {
 255                 return bh;
 256         }
 257         udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
 258                   block + UDF_SB_SESSION(sb), le16_to_cpu(tag_p->descCRC),
 259                   le16_to_cpu(tag_p->descCRCLength));
 260
 261       error_out:
 262         brelse(bh);
 263         return NULL;
 264 }
 265
 266 struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc,
 267                                      uint32_t offset, uint16_t * ident)
 268 {
 269         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
 270                                loc.logicalBlockNum + offset, ident);
 271 }
 272
 273 void udf_update_tag(char *data, int length)
 274 {
 275         tag *tptr = (tag *) data;
 276         int i;
 277
 278         length -= sizeof(tag);
 279
 280         tptr->tagChecksum = 0;
 281         tptr->descCRCLength = cpu_to_le16(length);
 282         tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
 283
 284         for (i = 0; i < 16; i++)
 285                 if (i != 4)
 286                         tptr->tagChecksum += (uint8_t) (data[i]);
 287 }
 288
 289 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
 290                  uint32_t loc, int length)
 291 {
 292         tag *tptr = (tag *) data;
 293         tptr->tagIdent = cpu_to_le16(ident);
 294         tptr->descVersion = cpu_to_le16(version);
 295         tptr->tagSerialNum = cpu_to_le16(snum);
 296         tptr->tagLocation = cpu_to_le32(loc);
 297         udf_update_tag(data, length);
 298 }