git.oblomov.eu Git - linux-2.6/blob - 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) != TAG_IDENT_EAHD ||
  80                             le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum) {
  81                                 return NULL;
  82                         }
  83                 } else {
  84                         size -= sizeof(struct extendedAttrHeaderDesc);
  85                         UDF_I_LENEATTR(inode) += sizeof(struct extendedAttrHeaderDesc);
  86                         eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
  87                         if (UDF_SB_UDFREV(inode->i_sb) >= 0x0200)
  88                                 eahd->descTag.descVersion = cpu_to_le16(3);
  89                         else
  90                                 eahd->descTag.descVersion = cpu_to_le16(2);
  91                         eahd->descTag.tagSerialNum = cpu_to_le16(UDF_SB_SERIALNUM(inode->i_sb));
  92                         eahd->descTag.tagLocation = cpu_to_le32(UDF_I_LOCATION(inode).logicalBlockNum);
  93                         eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
  94                         eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
  95                 }
  96
  97                 offset = UDF_I_LENEATTR(inode);
  98                 if (type < 2048) {
  99                         if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode)) {
 100                                 uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
 101                                 memmove(&ea[offset - aal + size],
 102                                         &ea[aal], offset - aal);
 103                                 offset -= aal;
 104                                 eahd->appAttrLocation = cpu_to_le32(aal + size);
 105                         }
 106                         if (le32_to_cpu(eahd->impAttrLocation) < UDF_I_LENEATTR(inode)) {
 107                                 uint32_t ial = le32_to_cpu(eahd->impAttrLocation);
 108                                 memmove(&ea[offset - ial + size],
 109                                         &ea[ial], offset - ial);
 110                                 offset -= ial;
 111                                 eahd->impAttrLocation = cpu_to_le32(ial + size);
 112                         }
 113                 } else if (type < 65536) {
 114                         if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode)) {
 115                                 uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
 116                                 memmove(&ea[offset - aal + size],
 117                                         &ea[aal], offset - aal);
 118                                 offset -= aal;
 119                                 eahd->appAttrLocation = cpu_to_le32(aal + size);
 120                         }
 121                 }
 122                 /* rewrite CRC + checksum of eahd */
 123                 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
 124                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
 125                 eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
 126                                                             sizeof(tag), crclen, 0));
 127                 eahd->descTag.tagChecksum = 0;
 128                 for (i = 0; i < 16; i++)
 129                         if (i != 4)
 130                                 eahd->descTag.tagChecksum += ((uint8_t *)&(eahd->descTag))[i];
 131                 UDF_I_LENEATTR(inode) += size;
 132                 return (struct genericFormat *)&ea[offset];
 133         }
 134         if (loc & 0x02) {
 135         }
 136
 137         return NULL;
 138 }
 139
 140 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
 141                                            uint8_t subtype)
 142 {
 143         struct genericFormat *gaf;
 144         uint8_t *ea = NULL;
 145         uint32_t offset;
 146
 147         ea = UDF_I_DATA(inode);
 148
 149         if (UDF_I_LENEATTR(inode)) {
 150                 struct extendedAttrHeaderDesc *eahd;
 151                 eahd = (struct extendedAttrHeaderDesc *)ea;
 152
 153                 /* check checksum/crc */
 154                 if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
 155                     le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum) {
 156                         return NULL;
 157                 }
 158
 159                 if (type < 2048)
 160                         offset = sizeof(struct extendedAttrHeaderDesc);
 161                 else if (type < 65536)
 162                         offset = le32_to_cpu(eahd->impAttrLocation);
 163                 else
 164                         offset = le32_to_cpu(eahd->appAttrLocation);
 165
 166                 while (offset < UDF_I_LENEATTR(inode)) {
 167                         gaf = (struct genericFormat *)&ea[offset];
 168                         if (le32_to_cpu(gaf->attrType) == type && gaf->attrSubtype == subtype)
 169                                 return gaf;
 170                         else
 171                                 offset += le32_to_cpu(gaf->attrLength);
 172                 }
 173         }
 174
 175         return NULL;
 176 }
 177
 178 /*
 179  * udf_read_tagged
 180  *
 181  * PURPOSE
 182  *      Read the first block of a tagged descriptor.
 183  *
 184  * HISTORY
 185  *      July 1, 1997 - Andrew E. Mileski
 186  *      Written, tested, and released.
 187  */
 188 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
 189                                     uint32_t location, uint16_t * ident)
 190 {
 191         tag *tag_p;
 192         struct buffer_head *bh = NULL;
 193         register uint8_t checksum;
 194         register int i;
 195
 196         /* Read the block */
 197         if (block == 0xFFFFFFFF)
 198                 return NULL;
 199
 200         bh = udf_tread(sb, block + UDF_SB_SESSION(sb));
 201         if (!bh) {
 202                 udf_debug("block=%d, location=%d: read failed\n",
 203                           block + UDF_SB_SESSION(sb), location);
 204                 return NULL;
 205         }
 206
 207         tag_p = (tag *)(bh->b_data);
 208
 209         *ident = le16_to_cpu(tag_p->tagIdent);
 210
 211         if (location != le32_to_cpu(tag_p->tagLocation)) {
 212                 udf_debug("location mismatch block %u, tag %u != %u\n",
 213                           block + UDF_SB_SESSION(sb), le32_to_cpu(tag_p->tagLocation), location);
 214                 goto error_out;
 215         }
 216
 217         /* Verify the tag checksum */
 218         checksum = 0U;
 219         for (i = 0; i < 4; i++)
 220                 checksum += (uint8_t)(bh->b_data[i]);
 221         for (i = 5; i < 16; i++)
 222                 checksum += (uint8_t)(bh->b_data[i]);
 223         if (checksum != tag_p->tagChecksum) {
 224                 printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
 225                 goto error_out;
 226         }
 227
 228         /* Verify the tag version */
 229         if (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
 230             le16_to_cpu(tag_p->descVersion) != 0x0003U) {
 231                 udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
 232                           le16_to_cpu(tag_p->descVersion), block);
 233                 goto error_out;
 234         }
 235
 236         /* Verify the descriptor CRC */
 237         if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
 238             le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
 239                                                    le16_to_cpu(tag_p->descCRCLength), 0)) {
 240                 return bh;
 241         }
 242         udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
 243                   block + UDF_SB_SESSION(sb), le16_to_cpu(tag_p->descCRC),
 244                   le16_to_cpu(tag_p->descCRCLength));
 245
 246 error_out:
 247         brelse(bh);
 248         return NULL;
 249 }
 250
 251 struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc,
 252                                      uint32_t offset, uint16_t * ident)
 253 {
 254         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
 255                                loc.logicalBlockNum + offset, ident);
 256 }
 257
 258 void udf_update_tag(char *data, int length)
 259 {
 260         tag *tptr = (tag *)data;
 261         int i;
 262
 263         length -= sizeof(tag);
 264
 265         tptr->tagChecksum = 0;
 266         tptr->descCRCLength = cpu_to_le16(length);
 267         tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
 268
 269         for (i = 0; i < 16; i++)
 270                 if (i != 4)
 271                         tptr->tagChecksum += (uint8_t)(data[i]);
 272 }
 273
 274 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
 275                  uint32_t loc, int length)
 276 {
 277         tag *tptr = (tag *)data;
 278         tptr->tagIdent = cpu_to_le16(ident);
 279         tptr->descVersion = cpu_to_le16(version);
 280         tptr->tagSerialNum = cpu_to_le16(snum);
 281         tptr->tagLocation = cpu_to_le32(loc);
 282         udf_update_tag(data, length);
 283 }