fs/msdos/namei.c

   1 /*
   2  *  linux/fs/msdos/namei.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
   6  *  Rewritten for constant inumbers 1999 by Al Viro
   7  */
   8
   9
  10 #define __NO_VERSION__
  11 #include <linux/module.h>
  12
  13 #include <linux/sched.h>
  14 #include <linux/msdos_fs.h>
  15 #include <linux/errno.h>
  16 #include <linux/string.h>
  17
  18 #include <asm/uaccess.h>
  19
  20 #include "../fat/msbuffer.h"
  21
  22 #define MSDOS_DEBUG 0
  23 #define PRINTK(x)
  24
  25 /* MS-DOS "device special files" */
  26
  27 static const char *reserved_names[] = {
  28     "CON     ","PRN     ","NUL     ","AUX     ",
  29     "LPT1    ","LPT2    ","LPT3    ","LPT4    ",
  30     "COM1    ","COM2    ","COM3    ","COM4    ",
  31     NULL };
  32
  33
  34 /* Characters that are undesirable in an MS-DOS file name */
  35
  36 static char bad_chars[] = "*?<>|\"";
  37 static char bad_if_strict_pc[] = "+=,; ";
  38 static char bad_if_strict_atari[] = " "; /* GEMDOS is less restrictive */
  39 #define bad_if_strict(opts) ((opts)->atari ? bad_if_strict_atari : bad_if_strict_pc)
  40
  41 /* Must die */
  42 void msdos_put_super(struct super_block *sb)
  43 {
  44         fat_put_super(sb);
  45 }
  46
  47 /***** Formats an MS-DOS file name. Rejects invalid names. */
  48 static int msdos_format_name(const char *name,int len,
  49         char *res,struct fat_mount_options *opts)
  50         /* conv is relaxed/normal/strict, name is proposed name,
  51          * len is the length of the proposed name, res is the result name,
  52          * dotsOK is if hidden files get dots.
  53          */
  54 {
  55         char *walk;
  56         const char **reserved;
  57         unsigned char c;
  58         int space;
  59
  60         if (name[0] == '.') {  /* dotfile because . and .. already done */
  61                 if (opts->dotsOK) {
  62                         /* Get rid of dot - test for it elsewhere */
  63                         name++; len--;
  64                 }
  65                 else if (!opts->atari) return -EINVAL;
  66         }
  67         /* disallow names that _really_ start with a dot for MS-DOS, GEMDOS does
  68          * not care */
  69         space = !opts->atari;
  70         c = 0;
  71         for (walk = res; len && walk-res < 8; walk++) {
  72                 c = *name++;
  73                 len--;
  74                 if (opts->conversion != 'r' && strchr(bad_chars,c))
  75                         return -EINVAL;
  76                 if (opts->conversion == 's' && strchr(bad_if_strict(opts),c))
  77                         return -EINVAL;
  78                 if (c >= 'A' && c <= 'Z' && opts->conversion == 's')
  79                         return -EINVAL;
  80                 if (c < ' ' || c == ':' || c == '\\') return -EINVAL;
  81 /*  0xE5 is legal as a first character, but we must substitute 0x05     */
  82 /*  because 0xE5 marks deleted files.  Yes, DOS really does this.       */
  83 /*  It seems that Microsoft hacked DOS to support non-US characters     */
  84 /*  after the 0xE5 character was already in use to mark deleted files.  */
  85                 if((res==walk) && (c==0xE5)) c=0x05;
  86                 if (c == '.') break;
  87                 space = (c == ' ');
  88                 *walk = (c >= 'a' && c <= 'z') ? c-32 : c;
  89         }
  90         if (space) return -EINVAL;
  91         if (opts->conversion == 's' && len && c != '.') {
  92                 c = *name++;
  93                 len--;
  94                 if (c != '.') return -EINVAL;
  95         }
  96         while (c != '.' && len--) c = *name++;
  97         if (c == '.') {
  98                 while (walk-res < 8) *walk++ = ' ';
  99                 while (len > 0 && walk-res < MSDOS_NAME) {
 100                         c = *name++;
 101                         len--;
 102                         if (opts->conversion != 'r' && strchr(bad_chars,c))
 103                                 return -EINVAL;
 104                         if (opts->conversion == 's' &&
 105                             strchr(bad_if_strict(opts),c))
 106                                 return -EINVAL;
 107                         if (c < ' ' || c == ':' || c == '\\')
 108                                 return -EINVAL;
 109                         if (c == '.') {
 110                                 if (opts->conversion == 's')
 111                                         return -EINVAL;
 112                                 break;
 113                         }
 114                         if (c >= 'A' && c <= 'Z' && opts->conversion == 's')
 115                                 return -EINVAL;
 116                         space = c == ' ';
 117                         *walk++ = c >= 'a' && c <= 'z' ? c-32 : c;
 118                 }
 119                 if (space) return -EINVAL;
 120                 if (opts->conversion == 's' && len) return -EINVAL;
 121         }
 122         while (walk-res < MSDOS_NAME) *walk++ = ' ';
 123         if (!opts->atari)
 124                 /* GEMDOS is less stupid and has no reserved names */
 125                 for (reserved = reserved_names; *reserved; reserved++)
 126                         if (!strncmp(res,*reserved,8)) return -EINVAL;
 127         return 0;
 128 }
 129
 130 /***** Locates a directory entry.  Uses unformatted name. */
 131 static int msdos_find(struct inode *dir,const char *name,int len,
 132     struct buffer_head **bh,struct msdos_dir_entry **de,int *ino)
 133 {
 134         int res;
 135         char dotsOK;
 136         char msdos_name[MSDOS_NAME];
 137
 138         dotsOK = MSDOS_SB(dir->i_sb)->options.dotsOK;
 139         res = msdos_format_name(name,len, msdos_name,&MSDOS_SB(dir->i_sb)->options);
 140         if (res < 0)
 141                 return -ENOENT;
 142         res = fat_scan(dir,msdos_name,bh,de,ino);
 143         if (!res && dotsOK) {
 144                 if (name[0]=='.') {
 145                         if (!((*de)->attr & ATTR_HIDDEN))
 146                                 res = -ENOENT;
 147                 } else {
 148                         if ((*de)->attr & ATTR_HIDDEN)
 149                                 res = -ENOENT;
 150                 }
 151         }
 152         return res;
 153
 154 }
 155
 156 /*
 157  * Compute the hash for the msdos name corresponding to the dentry.
 158  * Note: if the name is invalid, we leave the hash code unchanged so
 159  * that the existing dentry can be used. The msdos fs routines will
 160  * return ENOENT or EINVAL as appropriate.
 161  */
 162 static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
 163 {
 164         struct fat_mount_options *options = & (MSDOS_SB(dentry->d_sb)->options);
 165         int error;
 166         char msdos_name[MSDOS_NAME];
 167
 168         error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
 169         if (!error)
 170                 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
 171         return 0;
 172 }
 173
 174 /*
 175  * Compare two msdos names. If either of the names are invalid,
 176  * we fall back to doing the standard name comparison.
 177  */
 178 static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
 179 {
 180         struct fat_mount_options *options = & (MSDOS_SB(dentry->d_sb)->options);
 181         int error;
 182         char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
 183
 184         error = msdos_format_name(a->name, a->len, a_msdos_name, options);
 185         if (error)
 186                 goto old_compare;
 187         error = msdos_format_name(b->name, b->len, b_msdos_name, options);
 188         if (error)
 189                 goto old_compare;
 190         error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
 191 out:
 192         return error;
 193
 194 old_compare:
 195         error = 1;
 196         if (a->len == b->len)
 197                 error = memcmp(a->name, b->name, a->len);
 198         goto out;
 199 }
 200
 201
 202 static struct dentry_operations msdos_dentry_operations = {
 203         d_hash:         msdos_hash,
 204         d_compare:      msdos_cmp,
 205 };
 206
 207 /*
 208  * AV. Wrappers for FAT sb operations. Is it wise?
 209  */
 210
 211 /***** Get inode using directory and name */
 212 struct dentry *msdos_lookup(struct inode *dir,struct dentry *dentry)
 213 {
 214         struct super_block *sb = dir->i_sb;
 215         struct inode *inode = NULL;
 216         struct msdos_dir_entry *de;
 217         struct buffer_head *bh = NULL;
 218         int ino,res;
 219
 220         PRINTK (("msdos_lookup\n"));
 221
 222         dentry->d_op = &msdos_dentry_operations;
 223
 224         res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &bh,
 225                         &de, &ino);
 226
 227         if (res == -ENOENT)
 228                 goto add;
 229         if (res < 0)
 230                 goto out;
 231         inode = fat_build_inode(sb, de, ino, &res);
 232         if (res)
 233                 goto out;
 234 add:
 235         d_add(dentry, inode);
 236         res = 0;
 237 out:
 238         if (bh)
 239                 fat_brelse(sb, bh);
 240         return ERR_PTR(res);
 241 }
 242
 243 /***** Creates a directory entry (name is already formatted). */
 244 static int msdos_add_entry(struct inode *dir, const char *name,
 245                            struct buffer_head **bh,
 246                            struct msdos_dir_entry **de,
 247                            int *ino,
 248                            int is_dir, int is_hid)
 249 {
 250         struct super_block *sb = dir->i_sb;
 251         int res;
 252
 253         if ((res = fat_add_entries(dir, 1, bh, de, ino))<0)
 254                 return res;
 255         /*
 256          * XXX all times should be set by caller upon successful completion.
 257          */
 258         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 259         mark_inode_dirty(dir);
 260         memcpy((*de)->name,name,MSDOS_NAME);
 261         (*de)->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
 262         if (is_hid)
 263                 (*de)->attr |= ATTR_HIDDEN;
 264         (*de)->start = 0;
 265         (*de)->starthi = 0;
 266         fat_date_unix2dos(dir->i_mtime,&(*de)->time,&(*de)->date);
 267         (*de)->size = 0;
 268         fat_mark_buffer_dirty(sb, *bh, 1);
 269         return 0;
 270 }
 271
 272 /*
 273  * AV. Huh??? It's exported. Oughtta check usage.
 274  */
 275
 276 /***** Create a file */
 277 int msdos_create(struct inode *dir,struct dentry *dentry,int mode)
 278 {
 279         struct super_block *sb = dir->i_sb;
 280         struct buffer_head *bh;
 281         struct msdos_dir_entry *de;
 282         struct inode *inode;
 283         int ino,res,is_hid;
 284         char msdos_name[MSDOS_NAME];
 285
 286         res = msdos_format_name(dentry->d_name.name,dentry->d_name.len,
 287                                 msdos_name, &MSDOS_SB(sb)->options);
 288         if (res < 0)
 289                 return res;
 290         is_hid = (dentry->d_name.name[0]=='.') && (msdos_name[0]!='.');
 291         /* Have to do it due to foo vs. .foo conflicts */
 292         if (fat_scan(dir,msdos_name,&bh,&de,&ino) >= 0) {
 293                 fat_brelse(sb, bh);
 294                 return -EINVAL;
 295         }
 296         inode = NULL;
 297         res = msdos_add_entry(dir, msdos_name, &bh, &de, &ino, 0, is_hid);
 298         if (res)
 299                 return res;
 300         inode = fat_build_inode(dir->i_sb, de, ino, &res);
 301         fat_brelse(sb, bh);
 302         if (!inode)
 303                 return res;
 304         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 305         mark_inode_dirty(inode);
 306         d_instantiate(dentry, inode);
 307         return 0;
 308 }
 309
 310 /***** Remove a directory */
 311 int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 312 {
 313         struct super_block *sb = dir->i_sb;
 314         struct inode *inode = dentry->d_inode;
 315         int res,ino;
 316         struct buffer_head *bh;
 317         struct msdos_dir_entry *de;
 318
 319         bh = NULL;
 320         res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len,
 321                                 &bh, &de, &ino);
 322         if (res < 0)
 323                 goto rmdir_done;
 324         /*
 325          * Check whether the directory is not in use, then check
 326          * whether it is empty.
 327          */
 328         res = fat_dir_empty(inode);
 329         if (res)
 330                 goto rmdir_done;
 331
 332         de->name[0] = DELETED_FLAG;
 333         fat_mark_buffer_dirty(sb, bh, 1);
 334         fat_detach(inode);
 335         inode->i_nlink = 0;
 336         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 337         dir->i_nlink--;
 338         mark_inode_dirty(inode);
 339         mark_inode_dirty(dir);
 340         res = 0;
 341
 342 rmdir_done:
 343         fat_brelse(sb, bh);
 344         return res;
 345 }
 346
 347 /***** Make a directory */
 348 int msdos_mkdir(struct inode *dir,struct dentry *dentry,int mode)
 349 {
 350         struct super_block *sb = dir->i_sb;
 351         struct buffer_head *bh;
 352         struct msdos_dir_entry *de;
 353         struct inode *inode;
 354         int res,is_hid;
 355         char msdos_name[MSDOS_NAME];
 356         int ino;
 357
 358         res = msdos_format_name(dentry->d_name.name,dentry->d_name.len,
 359                                 msdos_name, &MSDOS_SB(sb)->options);
 360         if (res < 0)
 361                 return res;
 362         is_hid = (dentry->d_name.name[0]=='.') && (msdos_name[0]!='.');
 363         /* foo vs .foo situation */
 364         if (fat_scan(dir,msdos_name,&bh,&de,&ino) >= 0)
 365                 goto out_exist;
 366
 367         res = msdos_add_entry(dir, msdos_name, &bh, &de, &ino, 1, is_hid);
 368         if (res)
 369                 goto out_unlock;
 370         inode = fat_build_inode(dir->i_sb, de, ino, &res);
 371         if (!inode) {
 372                 fat_brelse(sb, bh);
 373                 goto out_unlock;
 374         }
 375         res = 0;
 376
 377         dir->i_nlink++;
 378         inode->i_nlink = 2; /* no need to mark them dirty */
 379
 380         res = fat_new_dir(inode, dir, 0);
 381         if (res)
 382                 goto mkdir_error;
 383
 384         fat_brelse(sb, bh);
 385         d_instantiate(dentry, inode);
 386         res = 0;
 387
 388 out_unlock:
 389         return res;
 390
 391 mkdir_error:
 392         printk("msdos_mkdir: error=%d, attempting cleanup\n", res);
 393         inode->i_nlink = 0;
 394         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 395         dir->i_nlink--;
 396         mark_inode_dirty(inode);
 397         mark_inode_dirty(dir);
 398         de->name[0] = DELETED_FLAG;
 399         fat_mark_buffer_dirty(sb, bh, 1);
 400         fat_brelse(sb, bh);
 401         fat_detach(inode);
 402         iput(inode);
 403         goto out_unlock;
 404
 405 out_exist:
 406         fat_brelse(sb, bh);
 407         res = -EINVAL;
 408         goto out_unlock;
 409 }
 410
 411 /***** Unlink a file */
 412 int msdos_unlink( struct inode *dir, struct dentry *dentry)
 413 {
 414         struct super_block *sb = dir->i_sb;
 415         struct inode *inode = dentry->d_inode;
 416         int res,ino;
 417         struct buffer_head *bh;
 418         struct msdos_dir_entry *de;
 419
 420         bh = NULL;
 421         res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len,
 422                         &bh, &de, &ino);
 423         if (res < 0)
 424                 goto unlink_done;
 425
 426         de->name[0] = DELETED_FLAG;
 427         fat_mark_buffer_dirty(sb, bh, 1);
 428         fat_detach(inode);
 429         fat_brelse(sb, bh);
 430         inode->i_nlink = 0;
 431         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 432         mark_inode_dirty(inode);
 433         mark_inode_dirty(dir);
 434         res = 0;
 435 unlink_done:
 436         return res;
 437 }
 438
 439 static int do_msdos_rename(struct inode *old_dir, char *old_name,
 440     struct dentry *old_dentry,
 441     struct inode *new_dir,char *new_name, struct dentry *new_dentry,
 442     struct buffer_head *old_bh,
 443     struct msdos_dir_entry *old_de, int old_ino, int is_hid)
 444 {
 445         struct super_block *sb = old_dir->i_sb;
 446         struct buffer_head *new_bh=NULL,*dotdot_bh=NULL;
 447         struct msdos_dir_entry *new_de,*dotdot_de;
 448         struct inode *old_inode,*new_inode;
 449         int new_ino,dotdot_ino;
 450         int error;
 451         int is_dir;
 452
 453         old_inode = old_dentry->d_inode;
 454         new_inode = new_dentry->d_inode;
 455         is_dir = S_ISDIR(old_inode->i_mode);
 456
 457         if (fat_scan(new_dir,new_name,&new_bh,&new_de,&new_ino)>=0 &&!new_inode)
 458                 goto degenerate_case;
 459         if (is_dir) {
 460                 if (new_inode) {
 461                         error = fat_dir_empty(new_inode);
 462                         if (error)
 463                                 goto out;
 464                 }
 465                 error = fat_scan(old_inode, MSDOS_DOTDOT, &dotdot_bh,
 466                                 &dotdot_de, &dotdot_ino);
 467                 if (error < 0) {
 468                         printk(KERN_WARNING
 469                                 "MSDOS: %s/%s, get dotdot failed, ret=%d\n",
 470                                 old_dentry->d_parent->d_name.name,
 471                                 old_dentry->d_name.name, error);
 472                         goto out;
 473                 }
 474         }
 475         if (!new_bh) {
 476                 error = msdos_add_entry(new_dir, new_name, &new_bh, &new_de,
 477                                         &new_ino, is_dir, is_hid);
 478                 if (error)
 479                         goto out;
 480         }
 481         new_dir->i_version = ++event;
 482
 483         /* There we go */
 484
 485         if (new_inode)
 486                 fat_detach(new_inode);
 487         old_de->name[0] = DELETED_FLAG;
 488         fat_mark_buffer_dirty(sb, old_bh, 1);
 489         fat_detach(old_inode);
 490         fat_attach(old_inode, new_ino);
 491         if (is_hid)
 492                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 493         else
 494                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 495         mark_inode_dirty(old_inode);
 496         old_dir->i_version = ++event;
 497         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
 498         mark_inode_dirty(old_dir);
 499         if (new_inode) {
 500                 new_inode->i_nlink--;
 501                 new_inode->i_ctime = CURRENT_TIME;
 502                 mark_inode_dirty(new_inode);
 503         }
 504         if (dotdot_bh) {
 505                 dotdot_de->start = CT_LE_W(MSDOS_I(new_dir)->i_logstart);
 506                 dotdot_de->starthi = CT_LE_W((MSDOS_I(new_dir)->i_logstart) >> 16);
 507                 fat_mark_buffer_dirty(sb, dotdot_bh, 1);
 508                 old_dir->i_nlink--;
 509                 mark_inode_dirty(old_dir);
 510                 if (new_inode) {
 511                         new_inode->i_nlink--;
 512                         mark_inode_dirty(new_inode);
 513                 } else {
 514                         new_dir->i_nlink++;
 515                         mark_inode_dirty(new_dir);
 516                 }
 517         }
 518         error = 0;
 519 out:
 520         fat_brelse(sb, new_bh);
 521         fat_brelse(sb, dotdot_bh);
 522         return error;
 523
 524 degenerate_case:
 525         error = -EINVAL;
 526         if (new_de!=old_de)
 527                 goto out;
 528         if (is_hid)
 529                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 530         else
 531                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 532         mark_inode_dirty(old_inode);
 533         old_dir->i_version = ++event;
 534         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
 535         mark_inode_dirty(old_dir);
 536         return 0;
 537 }
 538
 539 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
 540 int msdos_rename(struct inode *old_dir,struct dentry *old_dentry,
 541                  struct inode *new_dir,struct dentry *new_dentry)
 542 {
 543         struct super_block *sb = old_dir->i_sb;
 544         struct buffer_head *old_bh;
 545         struct msdos_dir_entry *old_de;
 546         int old_ino, error;
 547         int is_hid,old_hid; /* if new file and old file are hidden */
 548         char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
 549
 550         error = msdos_format_name(old_dentry->d_name.name,
 551                                   old_dentry->d_name.len,old_msdos_name,
 552                                   &MSDOS_SB(old_dir->i_sb)->options);
 553         if (error < 0)
 554                 goto rename_done;
 555         error = msdos_format_name(new_dentry->d_name.name,
 556                                   new_dentry->d_name.len,new_msdos_name,
 557                                   &MSDOS_SB(new_dir->i_sb)->options);
 558         if (error < 0)
 559                 goto rename_done;
 560
 561         is_hid  = (new_dentry->d_name.name[0]=='.') && (new_msdos_name[0]!='.');
 562         old_hid = (old_dentry->d_name.name[0]=='.') && (old_msdos_name[0]!='.');
 563         error = fat_scan(old_dir, old_msdos_name, &old_bh, &old_de, &old_ino);
 564         if (error < 0)
 565                 goto rename_done;
 566
 567         error = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
 568                                 new_dir, new_msdos_name, new_dentry,
 569                                 old_bh, old_de, (ino_t)old_ino, is_hid);
 570         fat_brelse(sb, old_bh);
 571
 572 rename_done:
 573         return error;
 574 }
 575
 576
 577 /* The public inode operations for the msdos fs */
 578 struct inode_operations msdos_dir_inode_operations = {
 579         create:         msdos_create,
 580         lookup:         msdos_lookup,
 581         unlink:         msdos_unlink,
 582         mkdir:          msdos_mkdir,
 583         rmdir:          msdos_rmdir,
 584         rename:         msdos_rename,
 585         setattr:        fat_notify_change,
 586 };
 587
 588 struct super_block *msdos_read_super(struct super_block *sb,void *data, int silent)
 589 {
 590         struct super_block *res;
 591
 592         MSDOS_SB(sb)->options.isvfat = 0;
 593         res = fat_read_super(sb, data, silent, &msdos_dir_inode_operations);
 594         if (res)
 595                 sb->s_root->d_op = &msdos_dentry_operations;
 596         return res;
 597 }