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/smp_lock.h>
  14 #include <linux/gfp.h>
  15 #include "isofs.h"
  16
  17 int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
  18 {
  19         char * old = de->name;
  20         int len = de->name_len[0];
  21         int i;
  22
  23         for (i = 0; i < len; i++) {
  24                 unsigned char c = old[i];
  25                 if (!c)
  26                         break;
  27
  28                 if (c >= 'A' && c <= 'Z')
  29                         c |= 0x20;      /* lower case */
  30
  31                 /* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
  32                 if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
  33                         break;
  34
  35                 /* Drop trailing ';1' */
  36                 if (c == ';' && i == len - 2 && old[i + 1] == '1')
  37                         break;
  38
  39                 /* Convert remaining ';' to '.' */
  40                 /* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
  41                 if (c == ';' || c == '/')
  42                         c = '.';
  43
  44                 new[i] = c;
  45         }
  46         return i;
  47 }
  48
  49 /* Acorn extensions written by Matthew Wilcox <willy@bofh.ai> 1998 */
  50 int get_acorn_filename(struct iso_directory_record *de,
  51                             char *retname, struct inode *inode)
  52 {
  53         int std;
  54         unsigned char *chr;
  55         int retnamlen = isofs_name_translate(de, retname, inode);
  56
  57         if (retnamlen == 0)
  58                 return 0;
  59         std = sizeof(struct iso_directory_record) + de->name_len[0];
  60         if (std & 1)
  61                 std++;
  62         if ((*((unsigned char *) de) - std) != 32)
  63                 return retnamlen;
  64         chr = ((unsigned char *) de) + std;
  65         if (strncmp(chr, "ARCHIMEDES", 10))
  66                 return retnamlen;
  67         if ((*retname == '_') && ((chr[19] & 1) == 1))
  68                 *retname = '!';
  69         if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
  70                 && ((chr[12] & 0xf0) == 0xf0)) {
  71                 retname[retnamlen] = ',';
  72                 sprintf(retname+retnamlen+1, "%3.3x",
  73                         ((chr[12] & 0xf) << 8) | chr[11]);
  74                 retnamlen += 4;
  75         }
  76         return retnamlen;
  77 }
  78
  79 /*
  80  * This should _really_ be cleaned up some day..
  81  */
  82 static int do_isofs_readdir(struct inode *inode, struct file *filp,
  83                 void *dirent, filldir_t filldir,
  84                 char *tmpname, struct iso_directory_record *tmpde)
  85 {
  86         unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
  87         unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
  88         unsigned long block, offset, block_saved, offset_saved;
  89         unsigned long inode_number = 0; /* Quiet GCC */
  90         struct buffer_head *bh = NULL;
  91         int len;
  92         int map;
  93         int first_de = 1;
  94         char *p = NULL;         /* Quiet GCC */
  95         struct iso_directory_record *de;
  96         struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
  97
  98         offset = filp->f_pos & (bufsize - 1);
  99         block = filp->f_pos >> bufbits;
 100
 101         while (filp->f_pos < inode->i_size) {
 102                 int de_len;
 103
 104                 if (!bh) {
 105                         bh = isofs_bread(inode, block);
 106                         if (!bh)
 107                                 return 0;
 108                 }
 109
 110                 de = (struct iso_directory_record *) (bh->b_data + offset);
 111
 112                 de_len = *(unsigned char *) de;
 113
 114                 /*
 115                  * If the length byte is zero, we should move on to the next
 116                  * CDROM sector.  If we are at the end of the directory, we
 117                  * kick out of the while loop.
 118                  */
 119
 120                 if (de_len == 0) {
 121                         brelse(bh);
 122                         bh = NULL;
 123                         filp->f_pos = (filp->f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
 124                         block = filp->f_pos >> bufbits;
 125                         offset = 0;
 126                         continue;
 127                 }
 128
 129                 block_saved = block;
 130                 offset_saved = offset;
 131                 offset += de_len;
 132
 133                 /* Make sure we have a full directory entry */
 134                 if (offset >= bufsize) {
 135                         int slop = bufsize - offset + de_len;
 136                         memcpy(tmpde, de, slop);
 137                         offset &= bufsize - 1;
 138                         block++;
 139                         brelse(bh);
 140                         bh = NULL;
 141                         if (offset) {
 142                                 bh = isofs_bread(inode, block);
 143                                 if (!bh)
 144                                         return 0;
 145                                 memcpy((void *) tmpde + slop, bh->b_data, offset);
 146                         }
 147                         de = tmpde;
 148                 }
 149                 /* Basic sanity check, whether name doesn't exceed dir entry */
 150                 if (de_len < de->name_len[0] +
 151                                         sizeof(struct iso_directory_record)) {
 152                         printk(KERN_NOTICE "iso9660: Corrupted directory entry"
 153                                " in block %lu of inode %lu\n", block,
 154                                inode->i_ino);
 155                         return -EIO;
 156                 }
 157
 158                 if (first_de) {
 159                         isofs_normalize_block_and_offset(de,
 160                                                         &block_saved,
 161                                                         &offset_saved);
 162                         inode_number = isofs_get_ino(block_saved,
 163                                                         offset_saved, bufbits);
 164                 }
 165
 166                 if (de->flags[-sbi->s_high_sierra] & 0x80) {
 167                         first_de = 0;
 168                         filp->f_pos += de_len;
 169                         continue;
 170                 }
 171                 first_de = 1;
 172
 173                 /* Handle the case of the '.' directory */
 174                 if (de->name_len[0] == 1 && de->name[0] == 0) {
 175                         if (filldir(dirent, ".", 1, filp->f_pos, inode->i_ino, DT_DIR) < 0)
 176                                 break;
 177                         filp->f_pos += de_len;
 178                         continue;
 179                 }
 180
 181                 len = 0;
 182
 183                 /* Handle the case of the '..' directory */
 184                 if (de->name_len[0] == 1 && de->name[0] == 1) {
 185                         inode_number = parent_ino(filp->f_path.dentry);
 186                         if (filldir(dirent, "..", 2, filp->f_pos, inode_number, DT_DIR) < 0)
 187                                 break;
 188                         filp->f_pos += de_len;
 189                         continue;
 190                 }
 191
 192                 /* Handle everything else.  Do name translation if there
 193                    is no Rock Ridge NM field. */
 194
 195                 /*
 196                  * Do not report hidden files if so instructed, or associated
 197                  * files unless instructed to do so
 198                  */
 199                 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
 200                     (!sbi->s_showassoc &&
 201                                 (de->flags[-sbi->s_high_sierra] & 4))) {
 202                         filp->f_pos += de_len;
 203                         continue;
 204                 }
 205
 206                 map = 1;
 207                 if (sbi->s_rock) {
 208                         len = get_rock_ridge_filename(de, tmpname, inode);
 209                         if (len != 0) {         /* may be -1 */
 210                                 p = tmpname;
 211                                 map = 0;
 212                         }
 213                 }
 214                 if (map) {
 215 #ifdef CONFIG_JOLIET
 216                         if (sbi->s_joliet_level) {
 217                                 len = get_joliet_filename(de, tmpname, inode);
 218                                 p = tmpname;
 219                         } else
 220 #endif
 221                         if (sbi->s_mapping == 'a') {
 222                                 len = get_acorn_filename(de, tmpname, inode);
 223                                 p = tmpname;
 224                         } else
 225                         if (sbi->s_mapping == 'n') {
 226                                 len = isofs_name_translate(de, tmpname, inode);
 227                                 p = tmpname;
 228                         } else {
 229                                 p = de->name;
 230                                 len = de->name_len[0];
 231                         }
 232                 }
 233                 if (len > 0) {
 234                         if (filldir(dirent, p, len, filp->f_pos, inode_number, DT_UNKNOWN) < 0)
 235                                 break;
 236                 }
 237                 filp->f_pos += de_len;
 238
 239                 continue;
 240         }
 241         if (bh)
 242                 brelse(bh);
 243         return 0;
 244 }
 245
 246 /*
 247  * Handle allocation of temporary space for name translation and
 248  * handling split directory entries.. The real work is done by
 249  * "do_isofs_readdir()".
 250  */
 251 static int isofs_readdir(struct file *filp,
 252                 void *dirent, filldir_t filldir)
 253 {
 254         int result;
 255         char *tmpname;
 256         struct iso_directory_record *tmpde;
 257         struct inode *inode = filp->f_path.dentry->d_inode;
 258
 259         tmpname = (char *)__get_free_page(GFP_KERNEL);
 260         if (tmpname == NULL)
 261                 return -ENOMEM;
 262
 263         lock_kernel();
 264         tmpde = (struct iso_directory_record *) (tmpname+1024);
 265
 266         result = do_isofs_readdir(inode, filp, dirent, filldir, tmpname, tmpde);
 267
 268         free_page((unsigned long) tmpname);
 269         unlock_kernel();
 270         return result;
 271 }
 272
 273 const struct file_operations isofs_dir_operations =
 274 {
 275         .llseek = generic_file_llseek,
 276         .read = generic_read_dir,
 277         .readdir = isofs_readdir,
 278 };
 279
 280 /*
 281  * directories can handle most operations...
 282  */
 283 const struct inode_operations isofs_dir_inode_operations =
 284 {
 285         .lookup = isofs_lookup,
 286 };
 287
 288