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
 205         pr_debug("%s(\"%pd\")\n", __func__, dentry);
 206
 207         affs_lock_dir(dir);
 208         bh = affs_find_entry(dir, dentry);
 209         if (IS_ERR(bh)) {
 210                 affs_unlock_dir(dir);
 211                 return ERR_CAST(bh);
 212         }
 213         if (bh) {
 214                 u32 ino = bh->b_blocknr;
 215
 216                 /* store the real header ino in d_fsdata for faster lookups */
 217                 dentry->d_fsdata = (void *)(long)ino;
 218                 switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 219                 //link to dirs disabled
 220                 //case ST_LINKDIR:
 221                 case ST_LINKFILE:
 222                         ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
 223                 }
 224                 affs_brelse(bh);
 225                 inode = affs_iget(sb, ino);
 226                 if (IS_ERR(inode)) {
 227                         affs_unlock_dir(dir);
 228                         return ERR_CAST(inode);
 229                 }
 230         }
 231         d_add(dentry, inode);
 232         affs_unlock_dir(dir);
 233         return NULL;
 234 }
 235
 236 int
 237 affs_unlink(struct inode *dir, struct dentry *dentry)
 238 {
 239         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
 240                  d_inode(dentry)->i_ino, dentry);
 241
 242         return affs_remove_header(dentry);
 243 }
 244
 245 int
 246 affs_create(struct inode *dir, 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 inode *dir, struct dentry *dentry, umode_t mode)
 278 {
 279         struct inode            *inode;
 280         int                      error;
 281
 282         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
 283                  __func__, dir->i_ino, dentry, mode);
 284
 285         inode = affs_new_inode(dir);
 286         if (!inode)
 287                 return -ENOSPC;
 288
 289         inode->i_mode = S_IFDIR | mode;
 290         affs_mode_to_prot(inode);
 291
 292         inode->i_op = &affs_dir_inode_operations;
 293         inode->i_fop = &affs_dir_operations;
 294
 295         error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
 296         if (error) {
 297                 clear_nlink(inode);
 298                 mark_inode_dirty(inode);
 299                 iput(inode);
 300                 return error;
 301         }
 302         return 0;
 303 }
 304
 305 int
 306 affs_rmdir(struct inode *dir, struct dentry *dentry)
 307 {
 308         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
 309                  d_inode(dentry)->i_ino, dentry);
 310
 311         return affs_remove_header(dentry);
 312 }
 313
 314 int
 315 affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 316 {
 317         struct super_block      *sb = dir->i_sb;
 318         struct buffer_head      *bh;
 319         struct inode            *inode;
 320         char                    *p;
 321         int                      i, maxlen, error;
 322         char                     c, lc;
 323
 324         pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
 325                  __func__, dir->i_ino, dentry, symname);
 326
 327         maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
 328         inode  = affs_new_inode(dir);
 329         if (!inode)
 330                 return -ENOSPC;
 331
 332         inode->i_op = &affs_symlink_inode_operations;
 333         inode_nohighmem(inode);
 334         inode->i_data.a_ops = &affs_symlink_aops;
 335         inode->i_mode = S_IFLNK | 0777;
 336         affs_mode_to_prot(inode);
 337
 338         error = -EIO;
 339         bh = affs_bread(sb, inode->i_ino);
 340         if (!bh)
 341                 goto err;
 342         i  = 0;
 343         p  = (char *)AFFS_HEAD(bh)->table;
 344         lc = '/';
 345         if (*symname == '/') {
 346                 struct affs_sb_info *sbi = AFFS_SB(sb);
 347                 while (*symname == '/')
 348                         symname++;
 349                 spin_lock(&sbi->symlink_lock);
 350                 while (sbi->s_volume[i])        /* Cannot overflow */
 351                         *p++ = sbi->s_volume[i++];
 352                 spin_unlock(&sbi->symlink_lock);
 353         }
 354         while (i < maxlen && (c = *symname++)) {
 355                 if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
 356                         *p++ = '/';
 357                         i++;
 358                         symname += 2;
 359                         lc = '/';
 360                 } else if (c == '.' && lc == '/' && *symname == '/') {
 361                         symname++;
 362                         lc = '/';
 363                 } else {
 364                         *p++ = c;
 365                         lc   = c;
 366                         i++;
 367                 }
 368                 if (lc == '/')
 369                         while (*symname == '/')
 370                                 symname++;
 371         }
 372         *p = 0;
 373         inode->i_size = i + 1;
 374         mark_buffer_dirty_inode(bh, inode);
 375         affs_brelse(bh);
 376         mark_inode_dirty(inode);
 377
 378         error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
 379         if (error)
 380                 goto err;
 381
 382         return 0;
 383
 384 err:
 385         clear_nlink(inode);
 386         mark_inode_dirty(inode);
 387         iput(inode);
 388         return error;
 389 }
 390
 391 int
 392 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
 393 {
 394         struct inode *inode = d_inode(old_dentry);
 395
 396         pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
 397                  dentry);
 398
 399         return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
 400 }
 401
 402 static int
 403 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
 404             struct inode *new_dir, struct dentry *new_dentry)
 405 {
 406         struct super_block *sb = old_dir->i_sb;
 407         struct buffer_head *bh = NULL;
 408         int retval;
 409
 410         retval = affs_check_name(new_dentry->d_name.name,
 411                                  new_dentry->d_name.len,
 412                                  affs_nofilenametruncate(old_dentry));
 413
 414         if (retval)
 415                 return retval;
 416
 417         /* Unlink destination if it already exists */
 418         if (d_really_is_positive(new_dentry)) {
 419                 retval = affs_remove_header(new_dentry);
 420                 if (retval)
 421                         return retval;
 422         }
 423
 424         bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
 425         if (!bh)
 426                 return -EIO;
 427
 428         /* Remove header from its parent directory. */
 429         affs_lock_dir(old_dir);
 430         retval = affs_remove_hash(old_dir, bh);
 431         affs_unlock_dir(old_dir);
 432         if (retval)
 433                 goto done;
 434
 435         /* And insert it into the new directory with the new name. */
 436         affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
 437         affs_fix_checksum(sb, bh);
 438         affs_lock_dir(new_dir);
 439         retval = affs_insert_hash(new_dir, bh);
 440         affs_unlock_dir(new_dir);
 441         /* TODO: move it back to old_dir, if error? */
 442
 443 done:
 444         mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
 445         affs_brelse(bh);
 446         return retval;
 447 }
 448
 449 static int
 450 affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
 451              struct inode *new_dir, struct dentry *new_dentry)
 452 {
 453
 454         struct super_block *sb = old_dir->i_sb;
 455         struct buffer_head *bh_old = NULL;
 456         struct buffer_head *bh_new = NULL;
 457         int retval;
 458
 459         bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
 460         if (!bh_old)
 461                 return -EIO;
 462
 463         bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
 464         if (!bh_new)
 465                 return -EIO;
 466
 467         /* Remove old header from its parent directory. */
 468         affs_lock_dir(old_dir);
 469         retval = affs_remove_hash(old_dir, bh_old);
 470         affs_unlock_dir(old_dir);
 471         if (retval)
 472                 goto done;
 473
 474         /* Remove new header from its parent directory. */
 475         affs_lock_dir(new_dir);
 476         retval = affs_remove_hash(new_dir, bh_new);
 477         affs_unlock_dir(new_dir);
 478         if (retval)
 479                 goto done;
 480
 481         /* Insert old into the new directory with the new name. */
 482         affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
 483         affs_fix_checksum(sb, bh_old);
 484         affs_lock_dir(new_dir);
 485         retval = affs_insert_hash(new_dir, bh_old);
 486         affs_unlock_dir(new_dir);
 487
 488         /* Insert new into the old directory with the old name. */
 489         affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
 490         affs_fix_checksum(sb, bh_new);
 491         affs_lock_dir(old_dir);
 492         retval = affs_insert_hash(old_dir, bh_new);
 493         affs_unlock_dir(old_dir);
 494 done:
 495         mark_buffer_dirty_inode(bh_old, new_dir);
 496         mark_buffer_dirty_inode(bh_new, old_dir);
 497         affs_brelse(bh_old);
 498         affs_brelse(bh_new);
 499         return retval;
 500 }
 501
 502 int affs_rename2(struct inode *old_dir, struct dentry *old_dentry,
 503                         struct inode *new_dir, struct dentry *new_dentry,
 504                         unsigned int flags)
 505 {
 506
 507         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
 508                 return -EINVAL;
 509
 510         pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
 511                  old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
 512
 513         if (flags & RENAME_EXCHANGE)
 514                 return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
 515
 516         return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
 517 }
 518
 519 static struct dentry *affs_get_parent(struct dentry *child)
 520 {
 521         struct inode *parent;
 522         struct buffer_head *bh;
 523
 524         bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
 525         if (!bh)
 526                 return ERR_PTR(-EIO);
 527
 528         parent = affs_iget(child->d_sb,
 529                            be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
 530         brelse(bh);
 531         if (IS_ERR(parent))
 532                 return ERR_CAST(parent);
 533
 534         return d_obtain_alias(parent);
 535 }
 536
 537 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
 538                                         u32 generation)
 539 {
 540         struct inode *inode;
 541
 542         if (!affs_validblock(sb, ino))
 543                 return ERR_PTR(-ESTALE);
 544
 545         inode = affs_iget(sb, ino);
 546         if (IS_ERR(inode))
 547                 return ERR_CAST(inode);
 548
 549         return inode;
 550 }
 551
 552 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
 553                                         int fh_len, int fh_type)
 554 {
 555         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 556                                     affs_nfs_get_inode);
 557 }
 558
 559 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
 560                                         int fh_len, int fh_type)
 561 {
 562         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 563                                     affs_nfs_get_inode);
 564 }
 565
 566 const struct export_operations affs_export_ops = {
 567         .fh_to_dentry = affs_fh_to_dentry,
 568         .fh_to_parent = affs_fh_to_parent,
 569         .get_parent = affs_get_parent,
 570 };
 571
 572 const struct dentry_operations affs_dentry_operations = {
 573         .d_hash         = affs_hash_dentry,
 574         .d_compare      = affs_compare_dentry,
 575 };
 576
 577 const struct dentry_operations affs_intl_dentry_operations = {
 578         .d_hash         = affs_intl_hash_dentry,
 579         .d_compare      = affs_intl_compare_dentry,
 580 };