fs/udf/directory.c

   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
  20 struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,
  21                                          struct udf_fileident_bh *fibh,
  22                                          struct fileIdentDesc *cfi,
  23                                          struct extent_position *epos,
  24                                          struct kernel_lb_addr *eloc, uint32_t *elen,
  25                                          sector_t *offset)
  26 {
  27         struct fileIdentDesc *fi;
  28         int i, num, block;
  29         struct buffer_head *tmp, *bha[16];
  30         struct udf_inode_info *iinfo = UDF_I(dir);
  31
  32         fibh->soffset = fibh->eoffset;
  33
  34         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
  35                 fi = udf_get_fileident(iinfo->i_ext.i_data -
  36                                        (iinfo->i_efe ?
  37                                         sizeof(struct extendedFileEntry) :
  38                                         sizeof(struct fileEntry)),
  39                                        dir->i_sb->s_blocksize,
  40                                        &(fibh->eoffset));
  41                 if (!fi)
  42                         return NULL;
  43
  44                 *nf_pos += fibh->eoffset - fibh->soffset;
  45
  46                 memcpy((uint8_t *)cfi, (uint8_t *)fi,
  47                        sizeof(struct fileIdentDesc));
  48
  49                 return fi;
  50         }
  51
  52         if (fibh->eoffset == dir->i_sb->s_blocksize) {
  53                 int lextoffset = epos->offset;
  54                 unsigned char blocksize_bits = dir->i_sb->s_blocksize_bits;
  55
  56                 if (udf_next_aext(dir, epos, eloc, elen, 1) !=
  57                     (EXT_RECORDED_ALLOCATED >> 30))
  58                         return NULL;
  59
  60                 block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
  61
  62                 (*offset)++;
  63
  64                 if ((*offset << blocksize_bits) >= *elen)
  65                         *offset = 0;
  66                 else
  67                         epos->offset = lextoffset;
  68
  69                 brelse(fibh->sbh);
  70                 fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
  71                 if (!fibh->sbh)
  72                         return NULL;
  73                 fibh->soffset = fibh->eoffset = 0;
  74
  75                 if (!(*offset & ((16 >> (blocksize_bits - 9)) - 1))) {
  76                         i = 16 >> (blocksize_bits - 9);
  77                         if (i + *offset > (*elen >> blocksize_bits))
  78                                 i = (*elen >> blocksize_bits)-*offset;
  79                         for (num = 0; i > 0; i--) {
  80                                 block = udf_get_lb_pblock(dir->i_sb, eloc,
  81                                                           *offset + i);
  82                                 tmp = udf_tgetblk(dir->i_sb, block);
  83                                 if (tmp && !buffer_uptodate(tmp) &&
  84                                                 !buffer_locked(tmp))
  85                                         bha[num++] = tmp;
  86                                 else
  87                                         brelse(tmp);
  88                         }
  89                         if (num) {
  90                                 ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha);
  91                                 for (i = 0; i < num; i++)
  92                                         brelse(bha[i]);
  93                         }
  94                 }
  95         } else if (fibh->sbh != fibh->ebh) {
  96                 brelse(fibh->sbh);
  97                 fibh->sbh = fibh->ebh;
  98         }
  99
 100         fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
 101                                &(fibh->eoffset));
 102
 103         if (!fi)
 104                 return NULL;
 105
 106         *nf_pos += fibh->eoffset - fibh->soffset;
 107
 108         if (fibh->eoffset <= dir->i_sb->s_blocksize) {
 109                 memcpy((uint8_t *)cfi, (uint8_t *)fi,
 110                        sizeof(struct fileIdentDesc));
 111         } else if (fibh->eoffset > dir->i_sb->s_blocksize) {
 112                 int lextoffset = epos->offset;
 113
 114                 if (udf_next_aext(dir, epos, eloc, elen, 1) !=
 115                     (EXT_RECORDED_ALLOCATED >> 30))
 116                         return NULL;
 117
 118                 block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
 119
 120                 (*offset)++;
 121
 122                 if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
 123                         *offset = 0;
 124                 else
 125                         epos->offset = lextoffset;
 126
 127                 fibh->soffset -= dir->i_sb->s_blocksize;
 128                 fibh->eoffset -= dir->i_sb->s_blocksize;
 129
 130                 fibh->ebh = udf_tread(dir->i_sb, block);
 131                 if (!fibh->ebh)
 132                         return NULL;
 133
 134                 if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
 135                         int fi_len;
 136
 137                         memcpy((uint8_t *)cfi, (uint8_t *)fi, -fibh->soffset);
 138                         memcpy((uint8_t *)cfi - fibh->soffset,
 139                                fibh->ebh->b_data,
 140                                sizeof(struct fileIdentDesc) + fibh->soffset);
 141
 142                         fi_len = (sizeof(struct fileIdentDesc) +
 143                                   cfi->lengthFileIdent +
 144                                   le16_to_cpu(cfi->lengthOfImpUse) + 3) & ~3;
 145
 146                         *nf_pos += fi_len - (fibh->eoffset - fibh->soffset);
 147                         fibh->eoffset = fibh->soffset + fi_len;
 148                 } else {
 149                         memcpy((uint8_t *)cfi, (uint8_t *)fi,
 150                                sizeof(struct fileIdentDesc));
 151                 }
 152         }
 153         /* Got last entry outside of dir size - fs is corrupted! */
 154         if (*nf_pos > dir->i_size)
 155                 return NULL;
 156         return fi;
 157 }
 158
 159 struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
 160 {
 161         struct fileIdentDesc *fi;
 162         int lengthThisIdent;
 163         uint8_t *ptr;
 164         int padlen;
 165
 166         if ((!buffer) || (!offset)) {
 167                 udf_debug("invalidparms, buffer=%p, offset=%p\n",
 168                           buffer, offset);
 169                 return NULL;
 170         }
 171
 172         ptr = buffer;
 173
 174         if ((*offset > 0) && (*offset < bufsize))
 175                 ptr += *offset;
 176         fi = (struct fileIdentDesc *)ptr;
 177         if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
 178                 udf_debug("0x%x != TAG_IDENT_FID\n",
 179                           le16_to_cpu(fi->descTag.tagIdent));
 180                 udf_debug("offset: %u sizeof: %lu bufsize: %u\n",
 181                           *offset, (unsigned long)sizeof(struct fileIdentDesc),
 182                           bufsize);
 183                 return NULL;
 184         }
 185         if ((*offset + sizeof(struct fileIdentDesc)) > bufsize)
 186                 lengthThisIdent = sizeof(struct fileIdentDesc);
 187         else
 188                 lengthThisIdent = sizeof(struct fileIdentDesc) +
 189                         fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);
 190
 191         /* we need to figure padding, too! */
 192         padlen = lengthThisIdent % UDF_NAME_PAD;
 193         if (padlen)
 194                 lengthThisIdent += (UDF_NAME_PAD - padlen);
 195         *offset = *offset + lengthThisIdent;
 196
 197         return fi;
 198 }
 199
 200 struct short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
 201                               int inc)
 202 {
 203         struct short_ad *sa;
 204
 205         if ((!ptr) || (!offset)) {
 206                 pr_err("%s: invalidparms\n", __func__);
 207                 return NULL;
 208         }
 209
 210         if ((*offset + sizeof(struct short_ad)) > maxoffset)
 211                 return NULL;
 212         else {
 213                 sa = (struct short_ad *)ptr;
 214                 if (sa->extLength == 0)
 215                         return NULL;
 216         }
 217
 218         if (inc)
 219                 *offset += sizeof(struct short_ad);
 220         return sa;
 221 }
 222
 223 struct long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
 224 {
 225         struct long_ad *la;
 226
 227         if ((!ptr) || (!offset)) {
 228                 pr_err("%s: invalidparms\n", __func__);
 229                 return NULL;
 230         }
 231
 232         if ((*offset + sizeof(struct long_ad)) > maxoffset)
 233                 return NULL;
 234         else {
 235                 la = (struct long_ad *)ptr;
 236                 if (la->extLength == 0)
 237                         return NULL;
 238         }
 239
 240         if (inc)
 241                 *offset += sizeof(struct long_ad);
 242         return la;
 243 }