fs/isofs/dir.c

   1 /*
   2  *  linux/fs/isofs/dir.c
   3  *
   4  *  (C) 1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
   5  *
   6  *  (C) 1991  Linus Torvalds - minix filesystem
   7  *
   8  *  Steve Beynon                       : Missing last directory entries fixed
   9  *  (stephen@askone.demon.co.uk)      : 21st June 1996
  10  *
  11  *  isofs directory handling functions
  12  */
  13 #include <linux/errno.h>
  14 #include <linux/fs.h>
  15 #include <linux/iso_fs.h>
  16 #include <linux/kernel.h>
  17 #include <linux/stat.h>
  18 #include <linux/string.h>
  19 #include <linux/mm.h>
  20 #include <linux/malloc.h>
  21 #include <linux/sched.h>
  22 #include <linux/locks.h>
  23 #include <linux/config.h>
  24
  25 #include <asm/uaccess.h>
  26
  27 static int isofs_readdir(struct file *, void *, filldir_t);
  28
  29 static struct file_operations isofs_dir_operations =
  30 {
  31         NULL,                   /* lseek - default */
  32         NULL,                   /* read */
  33         NULL,                   /* write - bad */
  34         isofs_readdir,          /* readdir */
  35         NULL,                   /* poll - default */
  36         NULL,                   /* ioctl - default */
  37         NULL,                   /* no special open code */
  38         NULL,                   /* flush */
  39         NULL,                   /* no special release code */
  40         NULL                    /* fsync */
  41 };
  42
  43 /*
  44  * directories can handle most operations...
  45  */
  46 struct inode_operations isofs_dir_inode_operations =
  47 {
  48         &isofs_dir_operations,  /* default directory file-ops */
  49         NULL,                   /* create */
  50         isofs_lookup,           /* lookup */
  51         NULL,                   /* link */
  52         NULL,                   /* unlink */
  53         NULL,                   /* symlink */
  54         NULL,                   /* mkdir */
  55         NULL,                   /* rmdir */
  56         NULL,                   /* mknod */
  57         NULL,                   /* rename */
  58         NULL,                   /* readlink */
  59         NULL,                   /* follow_link */
  60         NULL,                   /* readpage */
  61         NULL,                   /* writepage */
  62         NULL,                   /* bmap */
  63         NULL,                   /* truncate */
  64         NULL                    /* permission */
  65 };
  66
  67 static int isofs_name_translate(char * old, int len, char * new)
  68 {
  69         int i, c;
  70
  71         for (i = 0; i < len; i++) {
  72                 c = old[i];
  73                 if (!c)
  74                         break;
  75                 if (c >= 'A' && c <= 'Z')
  76                         c |= 0x20;      /* lower case */
  77
  78                 /* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
  79                 if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
  80                         break;
  81
  82                 /* Drop trailing ';1' */
  83                 if (c == ';' && i == len - 2 && old[i + 1] == '1')
  84                         break;
  85
  86                 /* Convert remaining ';' to '.' */
  87                 if (c == ';')
  88                         c = '.';
  89
  90                 new[i] = c;
  91         }
  92         return i;
  93 }
  94
  95 /* Acorn extensions written by Matthew Wilcox <willy@bofh.ai> 1998 */
  96 int get_acorn_filename(struct iso_directory_record * de,
  97                             char * retname, struct inode * inode)
  98 {
  99         int std;
 100         unsigned char * chr;
 101         int retnamlen = isofs_name_translate(de->name,
 102                                 de->name_len[0], retname);
 103         if (retnamlen == 0) return 0;
 104         std = sizeof(struct iso_directory_record) + de->name_len[0];
 105         if (std & 1) std++;
 106         if ((*((unsigned char *) de) - std) != 32) return retnamlen;
 107         chr = ((unsigned char *) de) + std;
 108         if (strncmp(chr, "ARCHIMEDES", 10)) return retnamlen;
 109         if ((*retname == '_') && ((chr[19] & 1) == 1)) *retname = '!';
 110         if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
 111                 && ((chr[12] & 0xf0) == 0xf0))
 112         {
 113                 retname[retnamlen] = ',';
 114                 sprintf(retname+retnamlen+1, "%3.3x",
 115                         ((chr[12] & 0xf) << 8) | chr[11]);
 116                 retnamlen += 4;
 117         }
 118         return retnamlen;
 119 }
 120
 121 /*
 122  * This should _really_ be cleaned up some day..
 123  */
 124 static int do_isofs_readdir(struct inode *inode, struct file *filp,
 125                 void *dirent, filldir_t filldir,
 126                 char * tmpname, struct iso_directory_record * tmpde)
 127 {
 128         unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 129         unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
 130         unsigned int block, offset;
 131         int inode_number = 0;   /* Quiet GCC */
 132         struct buffer_head *bh;
 133         int len;
 134         int map;
 135         int high_sierra;
 136         int first_de = 1;
 137         char *p = NULL;         /* Quiet GCC */
 138         struct iso_directory_record *de;
 139
 140         if (filp->f_pos >= inode->i_size)
 141                 return 0;
 142
 143         offset = filp->f_pos & (bufsize - 1);
 144         block = isofs_bmap(inode, filp->f_pos >> bufbits);
 145         high_sierra = inode->i_sb->u.isofs_sb.s_high_sierra;
 146
 147         if (!block)
 148                 return 0;
 149
 150         if (!(bh = breada(inode->i_dev, block, bufsize, filp->f_pos, inode->i_size)))
 151                 return 0;
 152
 153         while (filp->f_pos < inode->i_size) {
 154                 int de_len;
 155 #ifdef DEBUG
 156                 printk("Block, offset, f_pos: %x %x %x\n",
 157                        block, offset, filp->f_pos);
 158                 printk("inode->i_size = %x\n",inode->i_size);
 159 #endif
 160                 de = (struct iso_directory_record *) (bh->b_data + offset);
 161                 if(first_de) inode_number = (block << bufbits) + (offset & (bufsize - 1));
 162
 163                 de_len = *(unsigned char *) de;
 164 #ifdef DEBUG
 165                 printk("de_len = %ld\n", de_len);
 166 #endif
 167
 168
 169                 /* If the length byte is zero, we should move on to the next
 170                    CDROM sector.  If we are at the end of the directory, we
 171                    kick out of the while loop. */
 172
 173                 if ((de_len == 0) || (offset >= bufsize) ) {
 174                         brelse(bh);
 175                         if (de_len == 0) {
 176                                 filp->f_pos = ((filp->f_pos & ~(ISOFS_BLOCK_SIZE - 1))
 177                                                + ISOFS_BLOCK_SIZE);
 178                                 offset = 0;
 179                         } else {
 180                                 offset -= bufsize;
 181                                 filp->f_pos += offset;
 182                         }
 183
 184                         if (filp->f_pos >= inode->i_size)
 185                                 return 0;
 186
 187                         block = isofs_bmap(inode, (filp->f_pos) >> bufbits);
 188                         if (!block)
 189                                 return 0;
 190                         bh = breada(inode->i_dev, block, bufsize, filp->f_pos, inode->i_size);
 191                         if (!bh)
 192                                 return 0;
 193                         continue;
 194                 }
 195
 196                 offset +=  de_len;
 197                 if (offset > bufsize) {
 198                         /*
 199                          * This would only normally happen if we had
 200                          * a buggy cdrom image.  All directory
 201                          * entries should terminate with a null size
 202                          * or end exactly at the end of the sector.
 203                          */
 204                         printk("next_offset (%x) > bufsize (%lx)\n",
 205                                offset,bufsize);
 206                         break;
 207                 }
 208
 209                 if(de->flags[-high_sierra] & 0x80) {
 210                         first_de = 0;
 211                         filp->f_pos += de_len;
 212                         continue;
 213                 }
 214                 first_de = 1;
 215
 216                 /* Handle the case of the '.' directory */
 217                 if (de->name_len[0] == 1 && de->name[0] == 0) {
 218                         if (filldir(dirent, ".", 1, filp->f_pos, inode->i_ino) < 0)
 219                                 break;
 220                         filp->f_pos += de_len;
 221                         continue;
 222                 }
 223
 224                 len = 0;
 225
 226                 /* Handle the case of the '..' directory */
 227                 if (de->name_len[0] == 1 && de->name[0] == 1) {
 228                         inode_number = filp->f_dentry->d_parent->d_inode->i_ino;
 229                         if (filldir(dirent, "..", 2, filp->f_pos, inode_number) < 0)
 230                                 break;
 231                         filp->f_pos += de_len;
 232                         continue;
 233                 }
 234
 235                 /* Handle everything else.  Do name translation if there
 236                    is no Rock Ridge NM field. */
 237                 if (inode->i_sb->u.isofs_sb.s_unhide == 'n') {
 238                         /* Do not report hidden or associated files */
 239                         if (de->flags[-high_sierra] & 5) {
 240                                 filp->f_pos += de_len;
 241                                 continue;
 242                         }
 243                 }
 244
 245                 map = 1;
 246                 if (inode->i_sb->u.isofs_sb.s_rock) {
 247                         len = get_rock_ridge_filename(de, tmpname, inode);
 248                         if (len != 0) {
 249                                 p = tmpname;
 250                                 map = 0;
 251                         }
 252                 }
 253                 if (map) {
 254 #ifdef CONFIG_JOLIET
 255                         if (inode->i_sb->u.isofs_sb.s_joliet_level) {
 256                                 len = get_joliet_filename(de, inode, tmpname);
 257                                 p = tmpname;
 258                         } else
 259 #endif
 260                         if (inode->i_sb->u.isofs_sb.s_mapping == 'a') {
 261                                 len = get_acorn_filename(de, tmpname, inode);
 262                                 p = tmpname;
 263                         } else
 264                         if (inode->i_sb->u.isofs_sb.s_mapping == 'n') {
 265                                 len = isofs_name_translate(de->name,
 266                                         de->name_len[0], tmpname);
 267                                 p = tmpname;
 268                         } else {
 269                                 p = de->name;
 270                                 len = de->name_len[0];
 271                         }
 272                 }
 273                 if (len > 0) {
 274                         if (filldir(dirent, p, len, filp->f_pos, inode_number) < 0)
 275                                 break;
 276                 }
 277                 filp->f_pos += de_len;
 278
 279                 continue;
 280         }
 281         brelse(bh);
 282         return 0;
 283 }
 284
 285 /*
 286  * Handle allocation of temporary space for name translation and
 287  * handling split directory entries.. The real work is done by
 288  * "do_isofs_readdir()".
 289  */
 290 static int isofs_readdir(struct file *filp,
 291                 void *dirent, filldir_t filldir)
 292 {
 293         int result;
 294         char * tmpname;
 295         struct iso_directory_record * tmpde;
 296         struct inode *inode = filp->f_dentry->d_inode;
 297
 298         if (!inode || !S_ISDIR(inode->i_mode))
 299                 return -EBADF;
 300
 301         tmpname = (char *) __get_free_page(GFP_KERNEL);
 302         if (!tmpname)
 303                 return -ENOMEM;
 304         tmpde = (struct iso_directory_record *) (tmpname+1024);
 305
 306         result = do_isofs_readdir(inode, filp, dirent, filldir, tmpname, tmpde);
 307
 308         free_page((unsigned long) tmpname);
 309         return result;
 310 }