linux/fs/udf/misc.c
<<
>>
Prefs
   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
  32struct 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
  40struct 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
  48struct 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
 151struct 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 */
 202struct 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));
 256error_out:
 257        brelse(bh);
 258        return NULL;
 259}
 260
 261struct 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
 269void 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
 279void 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
 290u8 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}
 300
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.