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/gfp.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 *file,
  82                 struct dir_context *ctx,
  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 = ctx->pos & (bufsize - 1);
  98         block = ctx->pos >> bufbits;
  99
 100         while (ctx->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                         ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
 123                         block = ctx->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                 /* Basic sanity check, whether name doesn't exceed dir entry */
 149                 if (de_len < de->name_len[0] +
 150                                         sizeof(struct iso_directory_record)) {
 151                         printk(KERN_NOTICE "iso9660: Corrupted directory entry"
 152                                " in block %lu of inode %lu\n", block,
 153                                inode->i_ino);
 154                         return -EIO;
 155                 }
 156
 157                 if (first_de) {
 158                         isofs_normalize_block_and_offset(de,
 159                                                         &block_saved,
 160                                                         &offset_saved);
 161                         inode_number = isofs_get_ino(block_saved,
 162                                                         offset_saved, bufbits);
 163                 }
 164
 165                 if (de->flags[-sbi->s_high_sierra] & 0x80) {
 166                         first_de = 0;
 167                         ctx->pos += de_len;
 168                         continue;
 169                 }
 170                 first_de = 1;
 171
 172                 /* Handle the case of the '.' directory */
 173                 if (de->name_len[0] == 1 && de->name[0] == 0) {
 174                         if (!dir_emit_dot(file, ctx))
 175                                 break;
 176                         ctx->pos += de_len;
 177                         continue;
 178                 }
 179
 180                 len = 0;
 181
 182                 /* Handle the case of the '..' directory */
 183                 if (de->name_len[0] == 1 && de->name[0] == 1) {
 184                         if (!dir_emit_dotdot(file, ctx))
 185                                 break;
 186                         ctx->pos += de_len;
 187                         continue;
 188                 }
 189
 190                 /* Handle everything else.  Do name translation if there
 191                    is no Rock Ridge NM field. */
 192
 193                 /*
 194                  * Do not report hidden files if so instructed, or associated
 195                  * files unless instructed to do so
 196                  */
 197                 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
 198                     (!sbi->s_showassoc &&
 199                                 (de->flags[-sbi->s_high_sierra] & 4))) {
 200                         ctx->pos += de_len;
 201                         continue;
 202                 }
 203
 204                 map = 1;
 205                 if (sbi->s_rock) {
 206                         len = get_rock_ridge_filename(de, tmpname, inode);
 207                         if (len != 0) {         /* may be -1 */
 208                                 p = tmpname;
 209                                 map = 0;
 210                         }
 211                 }
 212                 if (map) {
 213 #ifdef CONFIG_JOLIET
 214                         if (sbi->s_joliet_level) {
 215                                 len = get_joliet_filename(de, tmpname, inode);
 216                                 p = tmpname;
 217                         } else
 218 #endif
 219                         if (sbi->s_mapping == 'a') {
 220                                 len = get_acorn_filename(de, tmpname, inode);
 221                                 p = tmpname;
 222                         } else
 223                         if (sbi->s_mapping == 'n') {
 224                                 len = isofs_name_translate(de, tmpname, inode);
 225                                 p = tmpname;
 226                         } else {
 227                                 p = de->name;
 228                                 len = de->name_len[0];
 229                         }
 230                 }
 231                 if (len > 0) {
 232                         if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN))
 233                                 break;
 234                 }
 235                 ctx->pos += de_len;
 236
 237                 continue;
 238         }
 239         if (bh)
 240                 brelse(bh);
 241         return 0;
 242 }
 243
 244 /*
 245  * Handle allocation of temporary space for name translation and
 246  * handling split directory entries.. The real work is done by
 247  * "do_isofs_readdir()".
 248  */
 249 static int isofs_readdir(struct file *file, struct dir_context *ctx)
 250 {
 251         int result;
 252         char *tmpname;
 253         struct iso_directory_record *tmpde;
 254         struct inode *inode = file_inode(file);
 255
 256         tmpname = (char *)__get_free_page(GFP_KERNEL);
 257         if (tmpname == NULL)
 258                 return -ENOMEM;
 259
 260         tmpde = (struct iso_directory_record *) (tmpname+1024);
 261
 262         result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde);
 263
 264         free_page((unsigned long) tmpname);
 265         return result;
 266 }
 267
 268 const struct file_operations isofs_dir_operations =
 269 {
 270         .llseek = generic_file_llseek,
 271         .read = generic_read_dir,
 272         .iterate = isofs_readdir,
 273 };
 274
 275 /*
 276  * directories can handle most operations...
 277  */
 278 const struct inode_operations isofs_dir_inode_operations =
 279 {
 280         .lookup = isofs_lookup,
 281 };
 282
 283