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