fs/udf/dir.c

   1 /*
   2  * dir.c
   3  *
   4  * PURPOSE
   5  *  Directory handling routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * CONTACTS
   8  *      E-mail regarding any portion of the Linux UDF file system should be
   9  *      directed to the development team mailing list (run by majordomo):
  10  *              linux_udf@hootie.lvld.hp.com
  11  *
  12  * COPYRIGHT
  13  *      This file is distributed under the terms of the GNU General Public
  14  *      License (GPL). Copies of the GPL can be obtained from:
  15  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  16  *      Each contributing author retains all rights to their own work.
  17  *
  18  *  (C) 1998-2000 Ben Fennema
  19  *
  20  * HISTORY
  21  *
  22  *  10/05/98 dgb  Split directory operations into it's own file
  23  *                Implemented directory reads via do_udf_readdir
  24  *  10/06/98      Made directory operations work!
  25  *  11/17/98      Rewrote directory to support ICB_FLAG_AD_LONG
  26  *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
  27  *                across blocks.
  28  *  12/12/98      Split out the lookup code to namei.c. bulk of directory
  29  *                code now in directory.c:udf_fileident_read.
  30  */
  31
  32 #include "udfdecl.h"
  33
  34 #if defined(__linux__) && defined(__KERNEL__)
  35 #include <linux/version.h>
  36 #include "udf_i.h"
  37 #include "udf_sb.h"
  38 #include <linux/string.h>
  39 #include <linux/errno.h>
  40 #include <linux/mm.h>
  41 #include <linux/malloc.h>
  42 #include <linux/udf_fs.h>
  43 #endif
  44
  45 /* Prototypes for file operations */
  46 static int udf_readdir(struct file *, void *, filldir_t);
  47 static int do_udf_readdir(struct inode *, struct file *, filldir_t, void *);
  48
  49 /* readdir and lookup functions */
  50
  51 struct file_operations udf_dir_operations = {
  52         read:                           generic_read_dir,
  53         readdir:                        udf_readdir,
  54         ioctl:                          udf_ioctl,
  55         fsync:                          udf_sync_file,
  56 };
  57
  58 /*
  59  * udf_readdir
  60  *
  61  * PURPOSE
  62  *      Read a directory entry.
  63  *
  64  * DESCRIPTION
  65  *      Optional - sys_getdents() will return -ENOTDIR if this routine is not
  66  *      available.
  67  *
  68  *      Refer to sys_getdents() in fs/readdir.c
  69  *      sys_getdents() -> .
  70  *
  71  * PRE-CONDITIONS
  72  *      filp                    Pointer to directory file.
  73  *      buf                     Pointer to directory entry buffer.
  74  *      filldir                 Pointer to filldir function.
  75  *
  76  * POST-CONDITIONS
  77  *      <return>                >=0 on success.
  78  *
  79  * HISTORY
  80  *      July 1, 1997 - Andrew E. Mileski
  81  *      Written, tested, and released.
  82  */
  83
  84 int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
  85 {
  86         struct inode *dir = filp->f_dentry->d_inode;
  87         int result;
  88
  89         if ( filp->f_pos == 0 )
  90         {
  91                 if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR))
  92                         return 0;
  93         }
  94
  95         result = do_udf_readdir(dir, filp, filldir, dirent);
  96         UPDATE_ATIME(dir);
  97         return result;
  98 }
  99
 100 static int
 101 do_udf_readdir(struct inode * dir, struct file *filp, filldir_t filldir, void *dirent)
 102 {
 103         struct udf_fileident_bh fibh;
 104         struct FileIdentDesc *fi=NULL;
 105         struct FileIdentDesc cfi;
 106         int block, iblock;
 107         loff_t nf_pos = filp->f_pos;
 108         int flen;
 109         char fname[255];
 110         char *nameptr;
 111         Uint16 liu;
 112         Uint8 lfi;
 113         loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
 114         struct buffer_head * bh = NULL;
 115         lb_addr bloc, eloc;
 116         Uint32 extoffset, elen, offset;
 117
 118         if (nf_pos >= size)
 119                 return 1;
 120
 121         if (nf_pos == 0)
 122                 nf_pos = (udf_ext0_offset(dir) >> 2);
 123
 124         fibh.soffset = fibh.eoffset = (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
 125         if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
 126                 &bloc, &extoffset, &eloc, &elen, &offset, &bh) == EXTENT_RECORDED_ALLOCATED)
 127         {
 128                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
 129                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
 130                 {
 131                         if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_SHORT)
 132                                 extoffset -= sizeof(short_ad);
 133                         else if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_LONG)
 134                                 extoffset -= sizeof(long_ad);
 135                 }
 136                 else
 137                         offset = 0;
 138         }
 139         else
 140         {
 141                 udf_release_data(bh);
 142                 return 0;
 143         }
 144
 145         if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block, dir->i_sb->s_blocksize)))
 146         {
 147                 udf_release_data(bh);
 148                 return 0;
 149         }
 150
 151         while ( nf_pos < size )
 152         {
 153                 filp->f_pos = nf_pos;
 154
 155                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &bloc, &extoffset, &eloc, &elen, &offset, &bh);
 156
 157                 if (!fi)
 158                 {
 159                         if (fibh.sbh != fibh.ebh)
 160                                 udf_release_data(fibh.ebh);
 161                         udf_release_data(fibh.sbh);
 162                         udf_release_data(bh);
 163                         return 1;
 164                 }
 165
 166                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 167                 lfi = cfi.lengthFileIdent;
 168
 169                 if (fibh.sbh == fibh.ebh)
 170                         nameptr = fi->fileIdent + liu;
 171                 else
 172                 {
 173                         int poffset;    /* Unpaded ending offset */
 174
 175                         poffset = fibh.soffset + sizeof(struct FileIdentDesc) + liu + lfi;
 176
 177                         if (poffset >= lfi)
 178                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 179                         else
 180                         {
 181                                 nameptr = fname;
 182                                 memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
 183                                 memcpy(nameptr + lfi - poffset, fibh.ebh->b_data, poffset);
 184                         }
 185                 }
 186
 187                 if ( (cfi.fileCharacteristics & FILE_DELETED) != 0 )
 188                 {
 189                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE) )
 190                                 continue;
 191                 }
 192
 193                 if ( (cfi.fileCharacteristics & FILE_HIDDEN) != 0 )
 194                 {
 195                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE) )
 196                                 continue;
 197                 }
 198
 199                 iblock = udf_get_lb_pblock(dir->i_sb, lelb_to_cpu(cfi.icb.extLocation), 0);
 200
 201                 if (!lfi) /* parent directory */
 202                 {
 203                         if (filldir(dirent, "..", 2, filp->f_pos, filp->f_dentry->d_parent->d_inode->i_ino, DT_DIR))
 204                         {
 205                                 if (fibh.sbh != fibh.ebh)
 206                                         udf_release_data(fibh.ebh);
 207                                 udf_release_data(fibh.sbh);
 208                                 udf_release_data(bh);
 209                                 return 1;
 210                         }
 211                 }
 212                 else
 213                 {
 214                         if ((flen = udf_get_filename(nameptr, fname, lfi)))
 215                         {
 216                                 if (filldir(dirent, fname, flen, filp->f_pos, iblock, DT_UNKNOWN))
 217                                 {
 218                                         if (fibh.sbh != fibh.ebh)
 219                                                 udf_release_data(fibh.ebh);
 220                                         udf_release_data(fibh.sbh);
 221                                         udf_release_data(bh);
 222                                         return 1; /* halt enum */
 223                                 }
 224                         }
 225                 }
 226         } /* end while */
 227
 228         filp->f_pos = nf_pos;
 229
 230         if (fibh.sbh != fibh.ebh)
 231                 udf_release_data(fibh.ebh);
 232         udf_release_data(fibh.sbh);
 233         udf_release_data(bh);
 234
 235         if ( filp->f_pos >= size)
 236                 return 1;
 237         else
 238                 return 0;
 239 }