fs/affs/namei.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/affs/namei.c
   4  *
   5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   6  *
   7  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   8  *
   9  *  (C) 1991  Linus Torvalds - minix filesystem
  10  */
  11
  12 #include "affs.h"
  13 #include <linux/exportfs.h>
  14
  15 typedef int (*toupper_t)(int);
  16
  17 /* Simple toupper() for DOS\1 */
  18
  19 static int
  20 affs_toupper(int ch)
  21 {
  22         return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
  23 }
  24
  25 /* International toupper() for DOS\3 ("international") */
  26
  27 static int
  28 affs_intl_toupper(int ch)
  29 {
  30         return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
  31                 && ch <= 0xFE && ch != 0xF7) ?
  32                 ch - ('a' - 'A') : ch;
  33 }
  34
  35 static inline toupper_t
  36 affs_get_toupper(struct super_block *sb)
  37 {
  38         return affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL) ?
  39                affs_intl_toupper : affs_toupper;
  40 }
  41
  42 /*
  43  * Note: the dentry argument is the parent dentry.
  44  */
  45 static inline int
  46 __affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
  47 {
  48         const u8 *name = qstr->name;
  49         unsigned long hash;
  50         int retval;
  51         u32 len;
  52
  53         retval = affs_check_name(qstr->name, qstr->len, notruncate);
  54         if (retval)
  55                 return retval;
  56
  57         hash = init_name_hash(dentry);
  58         len = min(qstr->len, AFFSNAMEMAX);
  59         for (; len > 0; name++, len--)
  60                 hash = partial_name_hash(toupper(*name), hash);
  61         qstr->hash = end_name_hash(hash);
  62
  63         return 0;
  64 }
  65
  66 static int
  67 affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
  68 {
  69         return __affs_hash_dentry(dentry, qstr, affs_toupper,
  70                                   affs_nofilenametruncate(dentry));
  71
  72 }
  73
  74 static int
  75 affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
  76 {
  77         return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
  78                                   affs_nofilenametruncate(dentry));
  79
  80 }
  81
  82 static inline int __affs_compare_dentry(unsigned int len,
  83                 const char *str, const struct qstr *name, toupper_t toupper,
  84                 bool notruncate)
  85 {
  86         const u8 *aname = str;
  87         const u8 *bname = name->name;
  88
  89         /*
  90          * 'str' is the name of an already existing dentry, so the name
  91          * must be valid. 'name' must be validated first.
  92          */
  93
  94         if (affs_check_name(name->name, name->len, notruncate))
  95                 return 1;
  96
  97         /*
  98          * If the names are longer than the allowed 30 chars,
  99          * the excess is ignored, so their length may differ.
 100          */
 101         if (len >= AFFSNAMEMAX) {
 102                 if (name->len < AFFSNAMEMAX)
 103                         return 1;
 104                 len = AFFSNAMEMAX;
 105         } else if (len != name->len)
 106                 return 1;
 107
 108         for (; len > 0; len--)
 109                 if (toupper(*aname++) != toupper(*bname++))
 110                         return 1;
 111
 112         return 0;
 113 }
 114
 115 static int
 116 affs_compare_dentry(const struct dentry *dentry,
 117                 unsigned int len, const char *str, const struct qstr *name)
 118 {
 119
 120         return __affs_compare_dentry(len, str, name, affs_toupper,
 121                                      affs_nofilenametruncate(dentry));
 122 }
 123
 124 static int
 125 affs_intl_compare_dentry(const struct dentry *dentry,
 126                 unsigned int len, const char *str, const struct qstr *name)
 127 {
 128         return __affs_compare_dentry(len, str, name, affs_intl_toupper,
 129                                      affs_nofilenametruncate(dentry));
 130
 131 }
 132
 133 /*
 134  * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
 135  */
 136
 137 static inline int
 138 affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
 139 {
 140         const u8 *name = dentry->d_name.name;
 141         int len = dentry->d_name.len;
 142
 143         if (len >= AFFSNAMEMAX) {
 144                 if (*name2 < AFFSNAMEMAX)
 145                         return 0;
 146                 len = AFFSNAMEMAX;
 147         } else if (len != *name2)
 148                 return 0;
 149
 150         for (name2++; len > 0; len--)
 151                 if (toupper(*name++) != toupper(*name2++))
 152                         return 0;
 153         return 1;
 154 }
 155
 156 int
 157 affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
 158 {
 159         toupper_t toupper = affs_get_toupper(sb);
 160         u32 hash;
 161
 162         hash = len = min(len, AFFSNAMEMAX);
 163         for (; len > 0; len--)
 164                 hash = (hash * 13 + toupper(*name++)) & 0x7ff;
 165
 166         return hash % AFFS_SB(sb)->s_hashsize;
 167 }
 168
 169 static struct buffer_head *
 170 affs_find_entry(struct inode *dir, struct dentry *dentry)
 171 {
 172         struct super_block *sb = dir->i_sb;
 173         struct buffer_head *bh;
 174         toupper_t toupper = affs_get_toupper(sb);
 175         u32 key;
 176
 177         pr_debug("%s(\"%pd\")\n", __func__, dentry);
 178
 179         bh = affs_bread(sb, dir->i_ino);
 180         if (!bh)
 181                 return ERR_PTR(-EIO);
 182
 183         key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
 184
 185         for (;;) {
 186                 affs_brelse(bh);
 187                 if (key == 0)
 188                         return NULL;
 189                 bh = affs_bread(sb, key);
 190                 if (!bh)
 191                         return ERR_PTR(-EIO);
 192                 if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
 193                         return bh;
 194                 key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
 195         }
 196 }
 197
 198 struct dentry *
 199 affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 200 {
 201         struct super_block *sb = dir->i_sb;
 202         struct buffer_head *bh;
 203         struct inode *inode = NULL;
 204         struct dentry *res;
 205
 206         pr_debug("%s(\"%pd\")\n", __func__, dentry);
 207
 208         affs_lock_dir(dir);
 209         bh = affs_find_entry(dir, dentry);
 210         if (IS_ERR(bh)) {
 211                 affs_unlock_dir(dir);
 212                 return ERR_CAST(bh);
 213         }
 214         if (bh) {
 215                 u32 ino = bh->b_blocknr;
 216
 217                 /* store the real header ino in d_fsdata for faster lookups */
 218                 dentry->d_fsdata = (void *)(long)ino;
 219                 switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 220                 //link to dirs disabled
 221                 //case ST_LINKDIR:
 222                 case ST_LINKFILE:
 223                         ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
 224                 }
 225                 affs_brelse(bh);
 226                 inode = affs_iget(sb, ino);
 227         }
 228         res = d_splice_alias(inode, dentry);
 229         if (!IS_ERR_OR_NULL(res))
 230                 res->d_fsdata = dentry->d_fsdata;
 231         affs_unlock_dir(dir);
 232         return res;
 233 }
 234
 235 int
 236 affs_unlink(struct inode *dir, struct dentry *dentry)
 237 {
 238         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
 239                  d_inode(dentry)->i_ino, dentry);
 240
 241         return affs_remove_header(dentry);
 242 }
 243
 244 int
 245 affs_create(struct user_namespace *mnt_userns, struct inode *dir,
 246             struct dentry *dentry, umode_t mode, bool excl)
 247 {
 248         struct super_block *sb = dir->i_sb;
 249         struct inode    *inode;
 250         int              error;
 251
 252         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
 253                  __func__, dir->i_ino, dentry, mode);
 254
 255         inode = affs_new_inode(dir);
 256         if (!inode)
 257                 return -ENOSPC;
 258
 259         inode->i_mode = mode;
 260         affs_mode_to_prot(inode);
 261         mark_inode_dirty(inode);
 262
 263         inode->i_op = &affs_file_inode_operations;
 264         inode->i_fop = &affs_file_operations;
 265         inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
 266                                   &affs_aops_ofs : &affs_aops;
 267         error = affs_add_entry(dir, inode, dentry, ST_FILE);
 268         if (error) {
 269                 clear_nlink(inode);
 270                 iput(inode);
 271                 return error;
 272         }
 273         return 0;
 274 }
 275
 276 int
 277 affs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 278            struct dentry *dentry, umode_t mode)
 279 {
 280         struct inode            *inode;
 281         int                      error;
 282
 283         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
 284                  __func__, dir->i_ino, dentry, mode);
 285
 286         inode = affs_new_inode(dir);
 287         if (!inode)
 288                 return -ENOSPC;
 289
 290         inode->i_mode = S_IFDIR | mode;
 291         affs_mode_to_prot(inode);
 292
 293         inode->i_op = &affs_dir_inode_operations;
 294         inode->i_fop = &affs_dir_operations;
 295
 296         error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
 297         if (error) {
 298                 clear_nlink(inode);
 299                 mark_inode_dirty(inode);
 300                 iput(inode);
 301                 return error;
 302         }
 303         return 0;
 304 }
 305
 306 int
 307 affs_rmdir(struct inode *dir, struct dentry *dentry)
 308 {
 309         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
 310                  d_inode(dentry)->i_ino, dentry);
 311
 312         return affs_remove_header(dentry);
 313 }
 314
 315 int
 316 affs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 317              struct dentry *dentry, const char *symname)
 318 {
 319         struct super_block      *sb = dir->i_sb;
 320         struct buffer_head      *bh;
 321         struct inode            *inode;
 322         char                    *p;
 323         int                      i, maxlen, error;
 324         char                     c, lc;
 325
 326         pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
 327                  __func__, dir->i_ino, dentry, symname);
 328
 329         maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
 330         inode  = affs_new_inode(dir);
 331         if (!inode)
 332                 return -ENOSPC;
 333
 334         inode->i_op = &affs_symlink_inode_operations;
 335         inode_nohighmem(inode);
 336         inode->i_data.a_ops = &affs_symlink_aops;
 337         inode->i_mode = S_IFLNK | 0777;
 338         affs_mode_to_prot(inode);
 339
 340         error = -EIO;
 341         bh = affs_bread(sb, inode->i_ino);
 342         if (!bh)
 343                 goto err;
 344         i  = 0;
 345         p  = (char *)AFFS_HEAD(bh)->table;
 346         lc = '/';
 347         if (*symname == '/') {
 348                 struct affs_sb_info *sbi = AFFS_SB(sb);
 349                 while (*symname == '/')
 350                         symname++;
 351                 spin_lock(&sbi->symlink_lock);
 352                 while (sbi->s_volume[i])        /* Cannot overflow */
 353                         *p++ = sbi->s_volume[i++];
 354                 spin_unlock(&sbi->symlink_lock);
 355         }
 356         while (i < maxlen && (c = *symname++)) {
 357                 if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
 358                         *p++ = '/';
 359                         i++;
 360                         symname += 2;
 361                         lc = '/';
 362                 } else if (c == '.' && lc == '/' && *symname == '/') {
 363                         symname++;
 364                         lc = '/';
 365                 } else {
 366                         *p++ = c;
 367                         lc   = c;
 368                         i++;
 369                 }
 370                 if (lc == '/')
 371                         while (*symname == '/')
 372                                 symname++;
 373         }
 374         *p = 0;
 375         inode->i_size = i + 1;
 376         mark_buffer_dirty_inode(bh, inode);
 377         affs_brelse(bh);
 378         mark_inode_dirty(inode);
 379
 380         error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
 381         if (error)
 382                 goto err;
 383
 384         return 0;
 385
 386 err:
 387         clear_nlink(inode);
 388         mark_inode_dirty(inode);
 389         iput(inode);
 390         return error;
 391 }
 392
 393 int
 394 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
 395 {
 396         struct inode *inode = d_inode(old_dentry);
 397
 398         pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
 399                  dentry);
 400
 401         return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
 402 }
 403
 404 static int
 405 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
 406             struct inode *new_dir, struct dentry *new_dentry)
 407 {
 408         struct super_block *sb = old_dir->i_sb;
 409         struct buffer_head *bh = NULL;
 410         int retval;
 411
 412         retval = affs_check_name(new_dentry->d_name.name,
 413                                  new_dentry->d_name.len,
 414                                  affs_nofilenametruncate(old_dentry));
 415
 416         if (retval)
 417                 return retval;
 418
 419         /* Unlink destination if it already exists */
 420         if (d_really_is_positive(new_dentry)) {
 421                 retval = affs_remove_header(new_dentry);
 422                 if (retval)
 423                         return retval;
 424         }
 425
 426         bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
 427         if (!bh)
 428                 return -EIO;
 429
 430         /* Remove header from its parent directory. */
 431         affs_lock_dir(old_dir);
 432         retval = affs_remove_hash(old_dir, bh);
 433         affs_unlock_dir(old_dir);
 434         if (retval)
 435                 goto done;
 436
 437         /* And insert it into the new directory with the new name. */
 438         affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
 439         affs_fix_checksum(sb, bh);
 440         affs_lock_dir(new_dir);
 441         retval = affs_insert_hash(new_dir, bh);
 442         affs_unlock_dir(new_dir);
 443         /* TODO: move it back to old_dir, if error? */
 444
 445 done:
 446         mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
 447         affs_brelse(bh);
 448         return retval;
 449 }
 450
 451 static int
 452 affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
 453              struct inode *new_dir, struct dentry *new_dentry)
 454 {
 455
 456         struct super_block *sb = old_dir->i_sb;
 457         struct buffer_head *bh_old = NULL;
 458         struct buffer_head *bh_new = NULL;
 459         int retval;
 460
 461         bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
 462         if (!bh_old)
 463                 return -EIO;
 464
 465         bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
 466         if (!bh_new)
 467                 return -EIO;
 468
 469         /* Remove old header from its parent directory. */
 470         affs_lock_dir(old_dir);
 471         retval = affs_remove_hash(old_dir, bh_old);
 472         affs_unlock_dir(old_dir);
 473         if (retval)
 474                 goto done;
 475
 476         /* Remove new header from its parent directory. */
 477         affs_lock_dir(new_dir);
 478         retval = affs_remove_hash(new_dir, bh_new);
 479         affs_unlock_dir(new_dir);
 480         if (retval)
 481                 goto done;
 482
 483         /* Insert old into the new directory with the new name. */
 484         affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
 485         affs_fix_checksum(sb, bh_old);
 486         affs_lock_dir(new_dir);
 487         retval = affs_insert_hash(new_dir, bh_old);
 488         affs_unlock_dir(new_dir);
 489
 490         /* Insert new into the old directory with the old name. */
 491         affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
 492         affs_fix_checksum(sb, bh_new);
 493         affs_lock_dir(old_dir);
 494         retval = affs_insert_hash(old_dir, bh_new);
 495         affs_unlock_dir(old_dir);
 496 done:
 497         mark_buffer_dirty_inode(bh_old, new_dir);
 498         mark_buffer_dirty_inode(bh_new, old_dir);
 499         affs_brelse(bh_old);
 500         affs_brelse(bh_new);
 501         return retval;
 502 }
 503
 504 int affs_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
 505                  struct dentry *old_dentry, struct inode *new_dir,
 506                  struct dentry *new_dentry, unsigned int flags)
 507 {
 508
 509         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
 510                 return -EINVAL;
 511
 512         pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
 513                  old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
 514
 515         if (flags & RENAME_EXCHANGE)
 516                 return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
 517
 518         return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
 519 }
 520
 521 static struct dentry *affs_get_parent(struct dentry *child)
 522 {
 523         struct inode *parent;
 524         struct buffer_head *bh;
 525
 526         bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
 527         if (!bh)
 528                 return ERR_PTR(-EIO);
 529
 530         parent = affs_iget(child->d_sb,
 531                            be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
 532         brelse(bh);
 533         if (IS_ERR(parent))
 534                 return ERR_CAST(parent);
 535
 536         return d_obtain_alias(parent);
 537 }
 538
 539 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
 540                                         u32 generation)
 541 {
 542         struct inode *inode;
 543
 544         if (!affs_validblock(sb, ino))
 545                 return ERR_PTR(-ESTALE);
 546
 547         inode = affs_iget(sb, ino);
 548         if (IS_ERR(inode))
 549                 return ERR_CAST(inode);
 550
 551         return inode;
 552 }
 553
 554 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
 555                                         int fh_len, int fh_type)
 556 {
 557         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 558                                     affs_nfs_get_inode);
 559 }
 560
 561 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
 562                                         int fh_len, int fh_type)
 563 {
 564         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 565                                     affs_nfs_get_inode);
 566 }
 567
 568 const struct export_operations affs_export_ops = {
 569         .fh_to_dentry = affs_fh_to_dentry,
 570         .fh_to_parent = affs_fh_to_parent,
 571         .get_parent = affs_get_parent,
 572 };
 573
 574 const struct dentry_operations affs_dentry_operations = {
 575         .d_hash         = affs_hash_dentry,
 576         .d_compare      = affs_compare_dentry,
 577 };
 578
 579 const struct dentry_operations affs_intl_dentry_operations = {
 580         .d_hash         = affs_intl_hash_dentry,
 581         .d_compare      = affs_intl_compare_dentry,
 582 };