fs/msdos/namei.c

/* */
This source file includes following definitions.
msdos_format_name
msdos_find
msdos_lookup
msdos_create_entry
msdos_create
dump_fat
msdos_mkdir
msdos_empty
msdos_rmdir
msdos_unlink
rename_same_dir
rename_diff_dir
msdos_rename
   1 /*
   2  *  linux/fs/msdos/namei.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  */
   6 
   7 #include <asm/segment.h>
   8 
   9 #include <linux/sched.h>
  10 #include <linux/msdos_fs.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/string.h>
  14 #include <linux/stat.h>
  15 
  16 /* MS-DOS "device special files" */
  17 
  18 static char *reserved_names[] = {
  19     "CON     ","PRN     ","NUL     ","AUX     ",
  20     "LPT1    ","LPT2    ","LPT3    ","LPT4    ",
  21     "COM1    ","COM2    ","COM3    ","COM4    ",
  22     NULL };
  23 
  24 
  25 /* Characters that are undesirable in an MS-DOS file name */
  26   
  27 static char bad_chars[] = "*?<>|\"";
  28 static char bad_if_strict[] = "+=,; ";
  29 
  30 
  31 /* Formats an MS-DOS file name. Rejects invalid names. */
  32 
  33 static int msdos_format_name(char conv,const char *name,int len,char *res,
     /*  */
  34   int dot_dirs)
  35 {
  36         char *walk,**reserved;
  37         unsigned char c;
  38         int space;
  39 
  40         if (IS_FREE(name)) return -EINVAL;
  41         if (name[0] == '.' && (len == 1 || (len == 2 && name[1] == '.'))) {
  42                 if (!dot_dirs) return -EEXIST;
  43                 memset(res+1,' ',10);
  44                 while (len--) *res++ = '.';
  45                 return 0;
  46         }
  47         space = 1; /* disallow names starting with a dot */
  48         c = 0;
  49         for (walk = res; len && walk-res < 8; walk++) {
  50                 c = *name++;
  51                 len--;
  52                 if (conv != 'r' && strchr(bad_chars,c)) return -EINVAL;
  53                 if (conv == 's' && strchr(bad_if_strict,c)) return -EINVAL;
  54                 if (c >= 'A' && c <= 'Z' && conv == 's') return -EINVAL;
  55                 if (c < ' ' || c == ':' || c == '\\') return -EINVAL;
  56                 if (c == '.') break;
  57                 space = c == ' ';
  58                 *walk = c >= 'a' && c <= 'z' ? c-32 : c;
  59         }
  60         if (space) return -EINVAL;
  61         if (conv == 's' && len && c != '.') {
  62                 c = *name++;
  63                 len--;
  64                 if (c != '.') return -EINVAL;
  65         }
  66         while (c != '.' && len--) c = *name++;
  67         if (c == '.') {
  68                 while (walk-res < 8) *walk++ = ' ';
  69                 while (len > 0 && walk-res < MSDOS_NAME) {
  70                         c = *name++;
  71                         len--;
  72                         if (conv != 'r' && strchr(bad_chars,c)) return -EINVAL;
  73                         if (conv == 's' && strchr(bad_if_strict,c))
  74                                 return -EINVAL;
  75                         if (c < ' ' || c == ':' || c == '\\' || c == '.')
  76                                 return -EINVAL;
  77                         if (c >= 'A' && c <= 'Z' && conv == 's') return -EINVAL;
  78                         space = c == ' ';
  79                         *walk++ = c >= 'a' && c <= 'z' ? c-32 : c;
  80                 }
  81                 if (space) return -EINVAL;
  82                 if (conv == 's' && len) return -EINVAL;
  83         }
  84         while (walk-res < MSDOS_NAME) *walk++ = ' ';
  85         for (reserved = reserved_names; *reserved; reserved++)
  86                 if (!strncmp(res,*reserved,8)) return -EINVAL;
  87         return 0;
  88 }
  89 
  90 
  91 /* Locates a directory entry. */
  92 
  93 static int msdos_find(struct inode *dir,const char *name,int len,
     /*  */
  94     struct buffer_head **bh,struct msdos_dir_entry **de,int *ino)
  95 {
  96         char msdos_name[MSDOS_NAME];
  97         int res;
  98 
  99         if ((res = msdos_format_name(MSDOS_SB(dir->i_sb)->name_check,name,len,
 100             msdos_name,1)) < 0) return res;
 101         return msdos_scan(dir,msdos_name,bh,de,ino);
 102 }
 103 
 104 
 105 int msdos_lookup(struct inode *dir,const char *name,int len,
     /*  */
 106     struct inode **result)
 107 {
 108         int ino,res;
 109         struct msdos_dir_entry *de;
 110         struct buffer_head *bh;
 111         struct inode *next;
 112 
 113         *result = NULL;
 114         if (!dir) return -ENOENT;
 115         if (!S_ISDIR(dir->i_mode)) {
 116                 iput(dir);
 117                 return -ENOENT;
 118         }
 119         if (len == 1 && name[0] == '.') {
 120                 *result = dir;
 121                 return 0;
 122         }
 123         if (len == 2 && name[0] == '.' && name[1] == '.') {
 124                 ino = msdos_parent_ino(dir,0);
 125                 iput(dir);
 126                 if (ino < 0) return ino;
 127                 if (!(*result = iget(dir->i_sb,ino))) return -EACCES;
 128                 return 0;
 129         }
 130         if ((res = msdos_find(dir,name,len,&bh,&de,&ino)) < 0) {
 131                 iput(dir);
 132                 return res;
 133         }
 134         if (bh) brelse(bh);
 135 /* printk("lookup: ino=%d\n",ino); */
 136         if (!(*result = iget(dir->i_sb,ino))) {
 137                 iput(dir);
 138                 return -EACCES;
 139         }
 140         if (MSDOS_I(*result)->i_busy) { /* mkdir in progress */
 141                 iput(*result);
 142                 iput(dir);
 143                 return -ENOENT;
 144         }
 145         while (MSDOS_I(*result)->i_old) {
 146                 next = MSDOS_I(*result)->i_old;
 147                 iput(*result);
 148                 if (!(*result = iget(next->i_sb,next->i_ino))) {
 149                         fs_panic(dir->i_sb,"msdos_lookup: Can't happen");
 150                         iput(dir);
 151                         return -ENOENT;
 152                 }
 153         }
 154         iput(dir);
 155         return 0;
 156 }
 157 
 158 
 159 /* Creates a directory entry (name is already formatted). */
 160 
 161 static int msdos_create_entry(struct inode *dir,char *name,int is_dir,
     /*  */
 162     struct inode **result)
 163 {
 164         struct buffer_head *bh;
 165         struct msdos_dir_entry *de;
 166         int res,ino;
 167 
 168         if ((res = msdos_scan(dir,NULL,&bh,&de,&ino)) < 0) {
 169                 if (res != -ENOENT) return res;
 170                 if (dir->i_ino == MSDOS_ROOT_INO) return -ENOSPC;
 171                 if ((res = msdos_add_cluster(dir)) < 0) return res;
 172                 if ((res = msdos_scan(dir,NULL,&bh,&de,&ino)) < 0) return res;
 173         }
 174         memcpy(de->name,name,MSDOS_NAME);
 175         de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
 176         de->start = 0;
 177         date_unix2dos(CURRENT_TIME,&de->time,&de->date);
 178         de->size = 0;
 179         bh->b_dirt = 1;
 180         if ((*result = iget(dir->i_sb,ino)) != NULL)
 181                 msdos_read_inode(*result);
 182         brelse(bh);
 183         if (!*result) return -EIO;
 184         (*result)->i_mtime = (*result)->i_atime = (*result)->i_ctime =
 185             CURRENT_TIME;
 186         (*result)->i_dirt = 1;
 187         return 0;
 188 }
 189 
 190 
 191 int msdos_create(struct inode *dir,const char *name,int len,int mode,
     /*  */
 192         struct inode **result)
 193 {
 194         struct buffer_head *bh;
 195         struct msdos_dir_entry *de;
 196         char msdos_name[MSDOS_NAME];
 197         int ino,res;
 198 
 199         if (!dir) return -ENOENT;
 200         if ((res = msdos_format_name(MSDOS_SB(dir->i_sb)->name_check,name,len,
 201             msdos_name,0)) < 0) {
 202                 iput(dir);
 203                 return res;
 204         }
 205         lock_creation();
 206         if (msdos_scan(dir,msdos_name,&bh,&de,&ino) >= 0) {
 207                 unlock_creation();
 208                 brelse(bh);
 209                 iput(dir);
 210                 return -EEXIST;
 211         }
 212         res = msdos_create_entry(dir,msdos_name,S_ISDIR(mode),result);
 213         unlock_creation();
 214         iput(dir);
 215         return res;
 216 }
 217 
 218 
 219 #ifdef DEBUG
 220 
 221 static void dump_fat(struct super_block *sb,int start)
     /*  */
 222 {
 223         printk("[");
 224         while (start) {
 225                 printk("%d ",start);
 226                 start = fat_access(sb,start,-1);
 227                 if (!start) {
 228                         printk("ERROR");
 229                         break;
 230                 }
 231                 if (start == -1) break;
 232         }
 233         printk("]\n");
 234 }
 235 
 236 #endif
 237 
 238 
 239 int msdos_mkdir(struct inode *dir,const char *name,int len,int mode)
     /*  */
 240 {
 241         struct buffer_head *bh;
 242         struct msdos_dir_entry *de;
 243         struct inode *inode,*dot;
 244         char msdos_name[MSDOS_NAME];
 245         int ino,res;
 246 
 247         if ((res = msdos_format_name(MSDOS_SB(dir->i_sb)->name_check,name,len,
 248             msdos_name,0)) < 0) {
 249                 iput(dir);
 250                 return res;
 251         }
 252         lock_creation();
 253         if (msdos_scan(dir,msdos_name,&bh,&de,&ino) >= 0) {
 254                 unlock_creation();
 255                 brelse(bh);
 256                 iput(dir);
 257                 return -EEXIST;
 258         }
 259         if ((res = msdos_create_entry(dir,msdos_name,1,&inode)) < 0) {
 260                 unlock_creation();
 261                 iput(dir);
 262                 return res;
 263         }
 264         dir->i_nlink++;
 265         inode->i_nlink = 2; /* no need to mark them dirty */
 266         MSDOS_I(inode)->i_busy = 1; /* prevent lookups */
 267         if ((res = msdos_add_cluster(inode)) < 0) goto mkdir_error;
 268         if ((res = msdos_create_entry(inode,MSDOS_DOT,1,&dot)) < 0)
 269                 goto mkdir_error;
 270         dot->i_size = inode->i_size; /* doesn't grow in the 2nd create_entry */
 271         MSDOS_I(dot)->i_start = MSDOS_I(inode)->i_start;
 272         dot->i_nlink = inode->i_nlink;
 273         dot->i_dirt = 1;
 274         iput(dot);
 275         if ((res = msdos_create_entry(inode,MSDOS_DOTDOT,1,&dot)) < 0)
 276                 goto mkdir_error;
 277         unlock_creation();
 278         dot->i_size = dir->i_size;
 279         MSDOS_I(dot)->i_start = MSDOS_I(dir)->i_start;
 280         dot->i_nlink = dir->i_nlink;
 281         dot->i_dirt = 1;
 282         MSDOS_I(inode)->i_busy = 0;
 283         iput(dot);
 284         iput(inode);
 285         iput(dir);
 286         return 0;
 287 mkdir_error:
 288         iput(inode);
 289         if (msdos_rmdir(dir,name,len) < 0)
 290                 fs_panic(dir->i_sb,"rmdir in mkdir failed");
 291         unlock_creation();
 292         return res;
 293 }
 294 
 295 
 296 static int msdos_empty(struct inode *dir)
     /*  */
 297 {
 298         off_t pos;
 299         struct buffer_head *bh;
 300         struct msdos_dir_entry *de;
 301 
 302         if (dir->i_count > 1)
 303                 return -EBUSY;
 304         if (MSDOS_I(dir)->i_start) { /* may be zero in mkdir */
 305                 pos = 0;
 306                 bh = NULL;
 307                 while (msdos_get_entry(dir,&pos,&bh,&de) > -1)
 308                         if (!IS_FREE(de->name) && strncmp(de->name,MSDOS_DOT,
 309                             MSDOS_NAME) && strncmp(de->name,MSDOS_DOTDOT,
 310                             MSDOS_NAME)) {
 311                                 brelse(bh);
 312                                 return -ENOTEMPTY;
 313                         }
 314                 if (bh)
 315                         brelse(bh);
 316         }
 317         return 0;
 318 }
 319 
 320 
 321 int msdos_rmdir(struct inode *dir,const char *name,int len)
     /*  */
 322 {
 323         int res,ino;
 324         struct buffer_head *bh;
 325         struct msdos_dir_entry *de;
 326         struct inode *inode;
 327 
 328         bh = NULL;
 329         inode = NULL;
 330         res = -EPERM;
 331         if (name[0] == '.' && (len == 1 || (len == 2 && name[1] == '.')))
 332                 goto rmdir_done;
 333         if ((res = msdos_find(dir,name,len,&bh,&de,&ino)) < 0) goto rmdir_done;
 334         res = -ENOENT;
 335         if (!(inode = iget(dir->i_sb,ino))) goto rmdir_done;
 336         res = -ENOTDIR;
 337         if (!S_ISDIR(inode->i_mode)) goto rmdir_done;
 338         res = -EBUSY;
 339         if (dir->i_dev != inode->i_dev || dir == inode) goto rmdir_done;
 340         res = msdos_empty(inode);
 341         if (res)
 342                 goto rmdir_done;
 343         inode->i_nlink = 0;
 344         dir->i_mtime = CURRENT_TIME;
 345         dir->i_nlink--;
 346         inode->i_dirt = dir->i_dirt = 1;
 347         de->name[0] = DELETED_FLAG;
 348         bh->b_dirt = 1;
 349         res = 0;
 350 rmdir_done:
 351         brelse(bh);
 352         iput(dir);
 353         iput(inode);
 354         return res;
 355 }
 356 
 357 
 358 int msdos_unlink(struct inode *dir,const char *name,int len)
     /*  */
 359 {
 360         int res,ino;
 361         struct buffer_head *bh;
 362         struct msdos_dir_entry *de;
 363         struct inode *inode;
 364 
 365         bh = NULL;
 366         inode = NULL;
 367         if ((res = msdos_find(dir,name,len,&bh,&de,&ino)) < 0)
 368                 goto unlink_done;
 369         if (!(inode = iget(dir->i_sb,ino))) {
 370                 res = -ENOENT;
 371                 goto unlink_done;
 372         }
 373         if (!S_ISREG(inode->i_mode)) {
 374                 res = -EPERM;
 375                 goto unlink_done;
 376         }
 377         inode->i_nlink = 0;
 378         MSDOS_I(inode)->i_busy = 1;
 379         inode->i_dirt = 1;
 380         de->name[0] = DELETED_FLAG;
 381         bh->b_dirt = 1;
 382 unlink_done:
 383         brelse(bh);
 384         iput(inode);
 385         iput(dir);
 386         return res;
 387 }
 388 
 389 
 390 static int rename_same_dir(struct inode *old_dir,char *old_name,
     /*  */
 391     struct inode *new_dir,char *new_name,struct buffer_head *old_bh,
 392     struct msdos_dir_entry *old_de,int old_ino)
 393 {
 394         struct buffer_head *new_bh;
 395         struct msdos_dir_entry *new_de;
 396         struct inode *new_inode,*old_inode;
 397         int new_ino,exists,error;
 398 
 399         if (!strncmp(old_name,new_name,MSDOS_NAME)) return 0;
 400         exists = msdos_scan(new_dir,new_name,&new_bh,&new_de,&new_ino) >= 0;
 401         if (*(unsigned char *) old_de->name == DELETED_FLAG) {
 402                 if (exists) brelse(new_bh);
 403                 return -ENOENT;
 404         }
 405         if (exists) {
 406                 if (!(new_inode = iget(new_dir->i_sb,new_ino))) {
 407                         brelse(new_bh);
 408                         return -EIO;
 409                 }
 410                 error = S_ISDIR(new_inode->i_mode) ? (old_de->attr & ATTR_DIR) ?
 411                     msdos_empty(new_inode) : -EPERM : (old_de->attr & ATTR_DIR)
 412                     ? -EPERM : 0;
 413                 if (error) {
 414                         iput(new_inode);
 415                         brelse(new_bh);
 416                         return error;
 417                 }
 418                 if (S_ISDIR(new_inode->i_mode)) {
 419                         new_dir->i_nlink--;
 420                         new_dir->i_dirt = 1;
 421                 }
 422                 new_inode->i_nlink = 0;
 423                 MSDOS_I(new_inode)->i_busy = 1;
 424                 new_inode->i_dirt = 1;
 425                 new_de->name[0] = DELETED_FLAG;
 426                 new_bh->b_dirt = 1;
 427                 iput(new_inode);
 428                 brelse(new_bh);
 429         }
 430         memcpy(old_de->name,new_name,MSDOS_NAME);
 431         old_bh->b_dirt = 1;
 432         if (MSDOS_SB(old_dir->i_sb)->conversion == 'a') /* update binary info */
 433                 if ((old_inode = iget(old_dir->i_sb,old_ino)) != NULL) {
 434                         msdos_read_inode(old_inode);
 435                         iput(old_inode);
 436                 }
 437         return 0;
 438 }
 439 
 440 
 441 static int rename_diff_dir(struct inode *old_dir,char *old_name,
     /*  */
 442     struct inode *new_dir,char *new_name,struct buffer_head *old_bh,
 443     struct msdos_dir_entry *old_de,int old_ino)
 444 {
 445         struct buffer_head *new_bh,*free_bh,*dotdot_bh;
 446         struct msdos_dir_entry *new_de,*free_de,*dotdot_de;
 447         struct inode *old_inode,*new_inode,*free_inode,*dotdot_inode,*walk;
 448         int new_ino,free_ino,dotdot_ino;
 449         int error,exists,ino;
 450 
 451         if (old_dir->i_dev != new_dir->i_dev) return -EINVAL;
 452         if (old_ino == new_dir->i_ino) return -EINVAL;
 453         if (!(walk = iget(new_dir->i_sb,new_dir->i_ino))) return -EIO;
 454         while (walk->i_ino != MSDOS_ROOT_INO) {
 455                 ino = msdos_parent_ino(walk,1);
 456                 iput(walk);
 457                 if (ino < 0) return ino;
 458                 if (ino == old_ino) return -EINVAL;
 459                 if (!(walk = iget(new_dir->i_sb,ino))) return -EIO;
 460         }
 461         iput(walk);
 462         while ((error = msdos_scan(new_dir,NULL,&free_bh,&free_de,&free_ino)) <
 463              0) {
 464                 if (error != -ENOENT) return error;
 465                 error = msdos_add_cluster(new_dir);
 466                 if (error) return error;
 467         }
 468         exists = msdos_scan(new_dir,new_name,&new_bh,&new_de,&new_ino) >= 0;
 469         if (!(old_inode = iget(old_dir->i_sb,old_ino))) {
 470                 brelse(free_bh);
 471                 if (exists) brelse(new_bh);
 472                 return -EIO;
 473         }
 474         if (*(unsigned char *) old_de->name == DELETED_FLAG) {
 475                 iput(old_inode);
 476                 brelse(free_bh);
 477                 if (exists) brelse(new_bh);
 478                 return -ENOENT;
 479         }
 480         new_inode = NULL; /* to make GCC happy */
 481         if (exists) {
 482                 if (!(new_inode = iget(new_dir->i_sb,new_ino))) {
 483                         iput(old_inode);
 484                         brelse(new_bh);
 485                         return -EIO;
 486                 }
 487                 error = S_ISDIR(new_inode->i_mode) ? (old_de->attr & ATTR_DIR) ?
 488                     msdos_empty(new_inode) : -EPERM : (old_de->attr & ATTR_DIR)
 489                     ? -EPERM : 0;
 490                 if (error) {
 491                         iput(new_inode);
 492                         iput(old_inode);
 493                         brelse(new_bh);
 494                         return error;
 495                 }
 496                 new_inode->i_nlink = 0;
 497                 MSDOS_I(new_inode)->i_busy = 1;
 498                 new_inode->i_dirt = 1;
 499                 new_de->name[0] = DELETED_FLAG;
 500                 new_bh->b_dirt = 1;
 501         }
 502         memcpy(free_de,old_de,sizeof(struct msdos_dir_entry));
 503         memcpy(free_de->name,new_name,MSDOS_NAME);
 504         if (!(free_inode = iget(new_dir->i_sb,free_ino))) {
 505                 free_de->name[0] = DELETED_FLAG;
 506 /*  Don't mark free_bh as dirty. Both states are supposed to be equivalent. */
 507                 brelse(free_bh);
 508                 if (exists) {
 509                         iput(new_inode);
 510                         brelse(new_bh);
 511                 }
 512                 return -EIO;
 513         }
 514         if (exists && S_ISDIR(new_inode->i_mode)) {
 515                 new_dir->i_nlink--;
 516                 new_dir->i_dirt = 1;
 517         }
 518         msdos_read_inode(free_inode);
 519         MSDOS_I(old_inode)->i_busy = 1;
 520         cache_inval_inode(old_inode);
 521         old_inode->i_dirt = 1;
 522         old_de->name[0] = DELETED_FLAG;
 523         old_bh->b_dirt = 1;
 524         free_bh->b_dirt = 1;
 525         if (!exists) iput(free_inode);
 526         else {
 527                 MSDOS_I(new_inode)->i_depend = free_inode;
 528                 MSDOS_I(free_inode)->i_old = new_inode;
 529                 /* free_inode is put when putting new_inode */
 530                 iput(new_inode);
 531                 brelse(new_bh);
 532         }
 533         if (S_ISDIR(old_inode->i_mode)) {
 534                 if ((error = msdos_scan(old_inode,MSDOS_DOTDOT,&dotdot_bh,
 535                     &dotdot_de,&dotdot_ino)) < 0) goto rename_done;
 536                 if (!(dotdot_inode = iget(old_inode->i_sb,dotdot_ino))) {
 537                         brelse(dotdot_bh);
 538                         error = -EIO;
 539                         goto rename_done;
 540                 }
 541                 dotdot_de->start = MSDOS_I(dotdot_inode)->i_start =
 542                     MSDOS_I(new_dir)->i_start;
 543                 dotdot_inode->i_dirt = 1;
 544                 dotdot_bh->b_dirt = 1;
 545                 old_dir->i_nlink--;
 546                 new_dir->i_nlink++;
 547                 /* no need to mark them dirty */
 548                 dotdot_inode->i_nlink = new_dir->i_nlink;
 549                 iput(dotdot_inode);
 550                 brelse(dotdot_bh);
 551         }
 552         error = 0;
 553 rename_done:
 554         brelse(free_bh);
 555         iput(old_inode);
 556         return error;
 557 }
 558 
 559 
 560 int msdos_rename(struct inode *old_dir,const char *old_name,int old_len,
     /*  */
 561         struct inode *new_dir,const char *new_name,int new_len)
 562 {
 563         char old_msdos_name[MSDOS_NAME],new_msdos_name[MSDOS_NAME];
 564         struct buffer_head *old_bh;
 565         struct msdos_dir_entry *old_de;
 566         int old_ino,error;
 567 
 568         if ((error = msdos_format_name(MSDOS_SB(old_dir->i_sb)->name_check,
 569             old_name,old_len,old_msdos_name,1)) < 0) goto rename_done;
 570         if ((error = msdos_format_name(MSDOS_SB(new_dir->i_sb)->name_check,
 571             new_name,new_len,new_msdos_name,0)) < 0) goto rename_done;
 572         if ((error = msdos_scan(old_dir,old_msdos_name,&old_bh,&old_de,
 573             &old_ino)) < 0) goto rename_done;
 574         lock_creation();
 575         if (old_dir == new_dir)
 576                 error = rename_same_dir(old_dir,old_msdos_name,new_dir,
 577                     new_msdos_name,old_bh,old_de,old_ino);
 578         else error = rename_diff_dir(old_dir,old_msdos_name,new_dir,
 579                     new_msdos_name,old_bh,old_de,old_ino);
 580         unlock_creation();
 581         brelse(old_bh);
 582 rename_done:
 583         iput(old_dir);
 584         iput(new_dir);
 585         return error;
 586 }
/* */
root/fs/msdos/namei.c

DEFINITIONS
