linux/fs/udf/directory.c
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   1/*
   2 * directory.c
   3 *
   4 * PURPOSE
   5 *      Directory related functions
   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
  14#include "udfdecl.h"
  15#include "udf_i.h"
  16
  17#include <linux/fs.h>
  18#include <linux/string.h>
  19#include <linux/buffer_head.h>
  20
  21struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,
  22                                         struct udf_fileident_bh *fibh,
  23                                         struct fileIdentDesc *cfi,
  24                                         struct extent_position *epos,
  25                                         struct kernel_lb_addr *eloc, uint32_t *elen,
  26                                         sector_t *offset)
  27{
  28        struct fileIdentDesc *fi;
  29        int i, num, block;
  30        struct buffer_head *tmp, *bha[16];
  31        struct udf_inode_info *iinfo = UDF_I(dir);
  32
  33        fibh->soffset = fibh->eoffset;
  34
  35        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
  36                fi = udf_get_fileident(iinfo->i_ext.i_data -
  37                                       (iinfo->i_efe ?
  38                                        sizeof(struct extendedFileEntry) :
  39                                        sizeof(struct fileEntry)),
  40                                       dir->i_sb->s_blocksize,
  41                                       &(fibh->eoffset));
  42                if (!fi)
  43                        return NULL;
  44
  45                *nf_pos += fibh->eoffset - fibh->soffset;
  46
  47                memcpy((uint8_t *)cfi, (uint8_t *)fi,
  48                       sizeof(struct fileIdentDesc));
  49
  50                return fi;
  51        }
  52
  53        if (fibh->eoffset == dir->i_sb->s_blocksize) {
  54                int lextoffset = epos->offset;
  55                unsigned char blocksize_bits = dir->i_sb->s_blocksize_bits;
  56
  57                if (udf_next_aext(dir, epos, eloc, elen, 1) !=
  58                    (EXT_RECORDED_ALLOCATED >> 30))
  59                        return NULL;
  60
  61                block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
  62
  63                (*offset)++;
  64
  65                if ((*offset << blocksize_bits) >= *elen)
  66                        *offset = 0;
  67                else
  68                        epos->offset = lextoffset;
  69
  70                brelse(fibh->sbh);
  71                fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
  72                if (!fibh->sbh)
  73                        return NULL;
  74                fibh->soffset = fibh->eoffset = 0;
  75
  76                if (!(*offset & ((16 >> (blocksize_bits - 9)) - 1))) {
  77                        i = 16 >> (blocksize_bits - 9);
  78                        if (i + *offset > (*elen >> blocksize_bits))
  79                                i = (*elen >> blocksize_bits)-*offset;
  80                        for (num = 0; i > 0; i--) {
  81                                block = udf_get_lb_pblock(dir->i_sb, eloc,
  82                                                          *offset + i);
  83                                tmp = udf_tgetblk(dir->i_sb, block);
  84                                if (tmp && !buffer_uptodate(tmp) &&
  85                                                !buffer_locked(tmp))
  86                                        bha[num++] = tmp;
  87                                else
  88                                        brelse(tmp);
  89                        }
  90                        if (num) {
  91                                ll_rw_block(READA, num, bha);
  92                                for (i = 0; i < num; i++)
  93                                        brelse(bha[i]);
  94                        }
  95                }
  96        } else if (fibh->sbh != fibh->ebh) {
  97                brelse(fibh->sbh);
  98                fibh->sbh = fibh->ebh;
  99        }
 100
 101        fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
 102                               &(fibh->eoffset));
 103
 104        if (!fi)
 105                return NULL;
 106
 107        *nf_pos += fibh->eoffset - fibh->soffset;
 108
 109        if (fibh->eoffset <= dir->i_sb->s_blocksize) {
 110                memcpy((uint8_t *)cfi, (uint8_t *)fi,
 111                       sizeof(struct fileIdentDesc));
 112        } else if (fibh->eoffset > dir->i_sb->s_blocksize) {
 113                int lextoffset = epos->offset;
 114
 115                if (udf_next_aext(dir, epos, eloc, elen, 1) !=
 116                    (EXT_RECORDED_ALLOCATED >> 30))
 117                        return NULL;
 118
 119                block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
 120
 121                (*offset)++;
 122
 123                if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
 124                        *offset = 0;
 125                else
 126                        epos->offset = lextoffset;
 127
 128                fibh->soffset -= dir->i_sb->s_blocksize;
 129                fibh->eoffset -= dir->i_sb->s_blocksize;
 130
 131                fibh->ebh = udf_tread(dir->i_sb, block);
 132                if (!fibh->ebh)
 133                        return NULL;
 134
 135                if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
 136                        int fi_len;
 137
 138                        memcpy((uint8_t *)cfi, (uint8_t *)fi, -fibh->soffset);
 139                        memcpy((uint8_t *)cfi - fibh->soffset,
 140                               fibh->ebh->b_data,
 141                               sizeof(struct fileIdentDesc) + fibh->soffset);
 142
 143                        fi_len = (sizeof(struct fileIdentDesc) +
 144                                  cfi->lengthFileIdent +
 145                                  le16_to_cpu(cfi->lengthOfImpUse) + 3) & ~3;
 146
 147                        *nf_pos += fi_len - (fibh->eoffset - fibh->soffset);
 148                        fibh->eoffset = fibh->soffset + fi_len;
 149                } else {
 150                        memcpy((uint8_t *)cfi, (uint8_t *)fi,
 151                               sizeof(struct fileIdentDesc));
 152                }
 153        }
 154        return fi;
 155}
 156
 157struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
 158{
 159        struct fileIdentDesc *fi;
 160        int lengthThisIdent;
 161        uint8_t *ptr;
 162        int padlen;
 163
 164        if ((!buffer) || (!offset)) {
 165                udf_debug("invalidparms, buffer=%p, offset=%p\n",
 166                          buffer, offset);
 167                return NULL;
 168        }
 169
 170        ptr = buffer;
 171
 172        if ((*offset > 0) && (*offset < bufsize))
 173                ptr += *offset;
 174        fi = (struct fileIdentDesc *)ptr;
 175        if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
 176                udf_debug("0x%x != TAG_IDENT_FID\n",
 177                          le16_to_cpu(fi->descTag.tagIdent));
 178                udf_debug("offset: %u sizeof: %lu bufsize: %u\n",
 179                          *offset, (unsigned long)sizeof(struct fileIdentDesc),
 180                          bufsize);
 181                return NULL;
 182        }
 183        if ((*offset + sizeof(struct fileIdentDesc)) > bufsize)
 184                lengthThisIdent = sizeof(struct fileIdentDesc);
 185        else
 186                lengthThisIdent = sizeof(struct fileIdentDesc) +
 187                        fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);
 188
 189        /* we need to figure padding, too! */
 190        padlen = lengthThisIdent % UDF_NAME_PAD;
 191        if (padlen)
 192                lengthThisIdent += (UDF_NAME_PAD - padlen);
 193        *offset = *offset + lengthThisIdent;
 194
 195        return fi;
 196}
 197
 198struct short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
 199                              int inc)
 200{
 201        struct short_ad *sa;
 202
 203        if ((!ptr) || (!offset)) {
 204                pr_err("%s: invalidparms\n", __func__);
 205                return NULL;
 206        }
 207
 208        if ((*offset + sizeof(struct short_ad)) > maxoffset)
 209                return NULL;
 210        else {
 211                sa = (struct short_ad *)ptr;
 212                if (sa->extLength == 0)
 213                        return NULL;
 214        }
 215
 216        if (inc)
 217                *offset += sizeof(struct short_ad);
 218        return sa;
 219}
 220
 221struct long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
 222{
 223        struct long_ad *la;
 224
 225        if ((!ptr) || (!offset)) {
 226                pr_err("%s: invalidparms\n", __func__);
 227                return NULL;
 228        }
 229
 230        if ((*offset + sizeof(struct long_ad)) > maxoffset)
 231                return NULL;
 232        else {
 233                la = (struct long_ad *)ptr;
 234                if (la->extLength == 0)
 235                        return NULL;
 236        }
 237
 238        if (inc)
 239                *offset += sizeof(struct long_ad);
 240        return la;
 241}
 242
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