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
  55         ea = UDF_I_DATA(inode);
  56         if (UDF_I_LENEATTR(inode)) {
  57                 ad = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
  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                 UDF_I_LENALLOC(inode);
  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 (UDF_I_LENALLOC(inode))
  73                         memmove(&ad[size], ad, UDF_I_LENALLOC(inode));
  74
  75                 if (UDF_I_LENEATTR(inode)) {
  76                         /* check checksum/crc */
  77                         if (le16_to_cpu(eahd->descTag.tagIdent) !=
  78                                         TAG_IDENT_EAHD ||
  79                             le32_to_cpu(eahd->descTag.tagLocation) !=
  80                                         UDF_I_LOCATION(inode).logicalBlockNum)
  81                                 return NULL;
  82                 } else {
  83                         struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
  84
  85                         size -= sizeof(struct extendedAttrHeaderDesc);
  86                         UDF_I_LENEATTR(inode) +=
  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                                         UDF_I_LOCATION(inode).logicalBlockNum);
  97                         eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
  98                         eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
  99                 }
 100
 101                 offset = UDF_I_LENEATTR(inode);
 102                 if (type < 2048) {
 103                         if (le32_to_cpu(eahd->appAttrLocation) <
 104                                         UDF_I_LENEATTR(inode)) {
 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                                         UDF_I_LENEATTR(inode)) {
 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                                         UDF_I_LENEATTR(inode)) {
 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(tag);
 137                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
 138                 eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
 139                                                 sizeof(tag), crclen, 0));
 140                 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
 141                 UDF_I_LENEATTR(inode) += size;
 142                 return (struct genericFormat *)&ea[offset];
 143         }
 144         if (loc & 0x02)
 145                 ;
 146
 147         return NULL;
 148 }
 149
 150 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
 151                                            uint8_t subtype)
 152 {
 153         struct genericFormat *gaf;
 154         uint8_t *ea = NULL;
 155         uint32_t offset;
 156
 157         ea = UDF_I_DATA(inode);
 158
 159         if (UDF_I_LENEATTR(inode)) {
 160                 struct extendedAttrHeaderDesc *eahd;
 161                 eahd = (struct extendedAttrHeaderDesc *)ea;
 162
 163                 /* check checksum/crc */
 164                 if (le16_to_cpu(eahd->descTag.tagIdent) !=
 165                                 TAG_IDENT_EAHD ||
 166                     le32_to_cpu(eahd->descTag.tagLocation) !=
 167                                 UDF_I_LOCATION(inode).logicalBlockNum)
 168                         return NULL;
 169
 170                 if (type < 2048)
 171                         offset = sizeof(struct extendedAttrHeaderDesc);
 172                 else if (type < 65536)
 173                         offset = le32_to_cpu(eahd->impAttrLocation);
 174                 else
 175                         offset = le32_to_cpu(eahd->appAttrLocation);
 176
 177                 while (offset < UDF_I_LENEATTR(inode)) {
 178                         gaf = (struct genericFormat *)&ea[offset];
 179                         if (le32_to_cpu(gaf->attrType) == type &&
 180                                         gaf->attrSubtype == subtype)
 181                                 return gaf;
 182                         else
 183                                 offset += le32_to_cpu(gaf->attrLength);
 184                 }
 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         struct udf_sb_info *sbi = UDF_SB(sb);
 206
 207         /* Read the block */
 208         if (block == 0xFFFFFFFF)
 209                 return NULL;
 210
 211         bh = udf_tread(sb, block + sbi->s_session);
 212         if (!bh) {
 213                 udf_debug("block=%d, location=%d: read failed\n",
 214                           block + sbi->s_session, location);
 215                 return NULL;
 216         }
 217
 218         tag_p = (tag *)(bh->b_data);
 219
 220         *ident = le16_to_cpu(tag_p->tagIdent);
 221
 222         if (location != le32_to_cpu(tag_p->tagLocation)) {
 223                 udf_debug("location mismatch block %u, tag %u != %u\n",
 224                           block + sbi->s_session,
 225                           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 (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
 237             le16_to_cpu(tag_p->descVersion) != 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(tag) > sb->s_blocksize ||
 245             le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
 246                                         le16_to_cpu(tag_p->descCRCLength), 0))
 247                 return bh;
 248
 249         udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
 250                   block + sbi->s_session, le16_to_cpu(tag_p->descCRC),
 251                   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, kernel_lb_addr loc,
 259                                      uint32_t offset, uint16_t *ident)
 260 {
 261         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
 262                                loc.logicalBlockNum + offset, ident);
 263 }
 264
 265 void udf_update_tag(char *data, int length)
 266 {
 267         tag *tptr = (tag *)data;
 268         length -= sizeof(tag);
 269
 270         tptr->descCRCLength = cpu_to_le16(length);
 271         tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
 272         tptr->tagChecksum = udf_tag_checksum(tptr);
 273 }
 274
 275 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
 276                  uint32_t loc, int length)
 277 {
 278         tag *tptr = (tag *)data;
 279         tptr->tagIdent = cpu_to_le16(ident);
 280         tptr->descVersion = cpu_to_le16(version);
 281         tptr->tagSerialNum = cpu_to_le16(snum);
 282         tptr->tagLocation = cpu_to_le32(loc);
 283         udf_update_tag(data, length);
 284 }
 285
 286 u8 udf_tag_checksum(const tag *t)
 287 {
 288         u8 *data = (u8 *)t;
 289         u8 checksum = 0;
 290         int i;
 291         for (i = 0; i < sizeof(tag); ++i)
 292                 if (i != 4) /* position of checksum */
 293                         checksum += data[i];
 294         return checksum;
 295 }