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 #include <linux/bio.h>
  20
  21 struct 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(REQ_OP_READ, REQ_RAHEAD, 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         /* Got last entry outside of dir size - fs is corrupted! */
 155         if (*nf_pos > dir->i_size)
 156                 return NULL;
 157         return fi;
 158 }
 159
 160 struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
 161 {
 162         struct fileIdentDesc *fi;
 163         int lengthThisIdent;
 164         uint8_t *ptr;
 165         int padlen;
 166
 167         if ((!buffer) || (!offset)) {
 168                 udf_debug("invalidparms, buffer=%p, offset=%p\n",
 169                           buffer, offset);
 170                 return NULL;
 171         }
 172
 173         ptr = buffer;
 174
 175         if ((*offset > 0) && (*offset < bufsize))
 176                 ptr += *offset;
 177         fi = (struct fileIdentDesc *)ptr;
 178         if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
 179                 udf_debug("0x%x != TAG_IDENT_FID\n",
 180                           le16_to_cpu(fi->descTag.tagIdent));
 181                 udf_debug("offset: %u sizeof: %lu bufsize: %u\n",
 182                           *offset, (unsigned long)sizeof(struct fileIdentDesc),
 183                           bufsize);
 184                 return NULL;
 185         }
 186         if ((*offset + sizeof(struct fileIdentDesc)) > bufsize)
 187                 lengthThisIdent = sizeof(struct fileIdentDesc);
 188         else
 189                 lengthThisIdent = sizeof(struct fileIdentDesc) +
 190                         fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);
 191
 192         /* we need to figure padding, too! */
 193         padlen = lengthThisIdent % UDF_NAME_PAD;
 194         if (padlen)
 195                 lengthThisIdent += (UDF_NAME_PAD - padlen);
 196         *offset = *offset + lengthThisIdent;
 197
 198         return fi;
 199 }
 200
 201 struct short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
 202                               int inc)
 203 {
 204         struct short_ad *sa;
 205
 206         if ((!ptr) || (!offset)) {
 207                 pr_err("%s: invalidparms\n", __func__);
 208                 return NULL;
 209         }
 210
 211         if ((*offset + sizeof(struct short_ad)) > maxoffset)
 212                 return NULL;
 213         else {
 214                 sa = (struct short_ad *)ptr;
 215                 if (sa->extLength == 0)
 216                         return NULL;
 217         }
 218
 219         if (inc)
 220                 *offset += sizeof(struct short_ad);
 221         return sa;
 222 }
 223
 224 struct long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
 225 {
 226         struct long_ad *la;
 227
 228         if ((!ptr) || (!offset)) {
 229                 pr_err("%s: invalidparms\n", __func__);
 230                 return NULL;
 231         }
 232
 233         if ((*offset + sizeof(struct long_ad)) > maxoffset)
 234                 return NULL;
 235         else {
 236                 la = (struct long_ad *)ptr;
 237                 if (la->extLength == 0)
 238                         return NULL;
 239         }
 240
 241         if (inc)
 242                 *offset += sizeof(struct long_ad);
 243         return la;
 244 }