fs/umsdos/ioctl.c

   1 /*
   2  *  linux/fs/umsdos/ioctl.c
   3  *
   4  *  Written 1993 by Jacques Gelinas
   5  *
   6  *  Extended MS-DOS ioctl directory handling functions
   7  *
   8  *  Changes:
   9  *  11/07/2003      Daniele Bellucci <bellucda@tiscali.it>
  10  *                  - audit copy_to_user/put_user in umsdos_ioctl_fill.
  11  */
  12
  13 #include <asm/uaccess.h>
  14 #include <linux/errno.h>
  15 #include <linux/mm.h>
  16 #include <linux/kernel.h>
  17 #include <linux/time.h>
  18 #include <linux/fs.h>
  19 #include <linux/msdos_fs.h>
  20 #include <linux/umsdos_fs.h>
  21
  22 struct UMSDOS_DIR_ONCE {
  23         struct dirent *ent;
  24         int count;
  25 };
  26
  27 /*
  28  * Record a single entry the first call.
  29  * Return -EINVAL the next one.
  30  */
  31 static int umsdos_ioctl_fill (
  32                                      void *buf,
  33                                      const char *name,
  34                                      int name_len,
  35                                      loff_t offset,
  36                                      ino_t ino,
  37                                      unsigned type)
  38 {
  39         int ret = -EINVAL;
  40         struct UMSDOS_DIR_ONCE *d = (struct UMSDOS_DIR_ONCE *) buf;
  41
  42         if (d->count == 0) {
  43                 if (copy_to_user (d->ent->d_name, name, name_len) ||
  44                     put_user ('\0', d->ent->d_name + name_len) ||
  45                     put_user (name_len, &d->ent->d_reclen) ||
  46                     put_user (ino, &d->ent->d_ino) ||
  47                     put_user (offset, &d->ent->d_off))
  48                         return -EFAULT;
  49                 d->count = 1;
  50                 ret = 0;
  51         }
  52         return ret;
  53 }
  54
  55
  56 /*
  57  * Perform special function on a directory
  58  */
  59 /* #Specification: ioctl / prototypes
  60  * The official prototype for the umsdos ioctl on directory
  61  * is:
  62  *
  63  * int ioctl (
  64  * int fd,          // File handle of the directory
  65  * int cmd, // command
  66  * struct umsdos_ioctl *data)
  67  *
  68  * The struct and the commands are defined in linux/umsdos_fs.h.
  69  *
  70  * umsdos_progs/umsdosio.c provide an interface in C++ to all
  71  * these ioctl. umsdos_progs/udosctl is a small utility showing
  72  * all this.
  73  *
  74  * These ioctl generally allow one to work on the EMD or the
  75  * DOS directory independently. These are essential to implement
  76  * the synchronise.
  77  */
  78 int UMSDOS_ioctl_dir(struct inode *dir, struct file *filp, unsigned int cmd,
  79                         unsigned long data_ptr)
  80 {
  81         struct dentry *dentry = filp->f_dentry;
  82         struct umsdos_ioctl *idata = (struct umsdos_ioctl *) data_ptr;
  83         int ret;
  84         struct umsdos_ioctl data;
  85
  86 Printk(("UMSDOS_ioctl_dir: %s/%s, cmd=%d, data=%08lx\n",
  87 dentry->d_parent->d_name.name, dentry->d_name.name, cmd, data_ptr));
  88
  89         /* forward non-umsdos ioctls - this hopefully doesn't cause conflicts */
  90         if (cmd != UMSDOS_GETVERSION
  91             && cmd != UMSDOS_READDIR_DOS
  92             && cmd != UMSDOS_READDIR_EMD
  93             && cmd != UMSDOS_INIT_EMD
  94             && cmd != UMSDOS_CREAT_EMD
  95             && cmd != UMSDOS_RENAME_DOS
  96             && cmd != UMSDOS_UNLINK_EMD
  97             && cmd != UMSDOS_UNLINK_DOS
  98             && cmd != UMSDOS_RMDIR_DOS
  99             && cmd != UMSDOS_STAT_DOS
 100             && cmd != UMSDOS_DOS_SETUP)
 101                 return fat_dir_ioctl (dir, filp, cmd, data_ptr);
 102
 103         /* #Specification: ioctl / access
 104          * Only root (effective id) is allowed to do IOCTL on directory
 105          * in UMSDOS. EPERM is returned for other user.
 106          */
 107         /*
 108          * Well, not all cases require write access, but it simplifies
 109          * the code, and let's face it, there is only one client (umssync)
 110          * for all this.
 111          */
 112         ret = verify_area (VERIFY_WRITE, (void *) data_ptr,
 113                                 sizeof (struct umsdos_ioctl));
 114         if (ret < 0)
 115                 goto out;
 116
 117         ret = -EPERM;
 118         if (current->euid != 0 && cmd != UMSDOS_GETVERSION)
 119                 goto out;
 120
 121         ret = -EINVAL;
 122         if (cmd == UMSDOS_GETVERSION) {
 123                 /* #Specification: ioctl / UMSDOS_GETVERSION
 124                  * The field version and release of the structure
 125                  * umsdos_ioctl are filled with the version and release
 126                  * number of the fs code in the kernel. This will allow
 127                  * some form of checking. Users won't be able to run
 128                  * incompatible utility such as the synchroniser (umssync).
 129                  * umsdos_progs/umsdosio.c enforce this checking.
 130                  *
 131                  * Return always 0.
 132                  */
 133                 put_user (UMSDOS_VERSION, &idata->version);
 134                 put_user (UMSDOS_RELEASE, &idata->release);
 135                 ret = 0;
 136                 goto out;
 137         }
 138         if (cmd == UMSDOS_READDIR_DOS) {
 139                 /* #Specification: ioctl / UMSDOS_READDIR_DOS
 140                  * One entry is read from the DOS directory at the current
 141                  * file position. The entry is put as is in the dos_dirent
 142                  * field of struct umsdos_ioctl.
 143                  *
 144                  * Return > 0 if success.
 145                  */
 146                 struct UMSDOS_DIR_ONCE bufk;
 147
 148                 bufk.count = 0;
 149                 bufk.ent = &idata->dos_dirent;
 150
 151                 fat_readdir (filp, &bufk, umsdos_ioctl_fill);
 152
 153                 ret = bufk.count == 1 ? 1 : 0;
 154                 goto out;
 155         }
 156         if (cmd == UMSDOS_READDIR_EMD) {
 157                 /* #Specification: ioctl / UMSDOS_READDIR_EMD
 158                  * One entry is read from the EMD at the current
 159                  * file position. The entry is put as is in the umsdos_dirent
 160                  * field of struct umsdos_ioctl. The corresponding mangled
 161                  * DOS entry name is put in the dos_dirent field.
 162                  *
 163                  * All entries are read including hidden links. Blank
 164                  * entries are skipped.
 165                  *
 166                  * Return > 0 if success.
 167                  */
 168                 struct dentry *demd;
 169                 loff_t pos = filp->f_pos;
 170
 171                 /* The absence of the EMD is simply seen as an EOF */
 172                 demd = umsdos_get_emd_dentry(dentry);
 173                 ret = PTR_ERR(demd);
 174                 if (IS_ERR(demd))
 175                         goto out;
 176                 ret = 0;
 177                 if (!demd->d_inode)
 178                         goto read_dput;
 179
 180                 while (pos < demd->d_inode->i_size) {
 181                         off_t f_pos = pos;
 182                         struct umsdos_dirent entry;
 183                         struct umsdos_info info;
 184
 185                         ret = umsdos_emd_dir_readentry (demd, &pos, &entry);
 186
 187                         if (ret == -ENAMETOOLONG) {
 188                                 printk (KERN_INFO "Fixing EMD entry with invalid size -- zeroing out\n");
 189                                 memset (&info, 0, sizeof (info));
 190                                 info.f_pos = f_pos;
 191                                 info.recsize = UMSDOS_REC_SIZE;
 192                                 ret = umsdos_writeentry (dentry, &info, 1);
 193                                 continue;
 194                         }
 195
 196                         if (ret)
 197                                 break;
 198                         if (entry.name_len <= 0)
 199                                 continue;
 200
 201                         umsdos_parse (entry.name, entry.name_len, &info);
 202                         info.f_pos = f_pos;
 203                         umsdos_manglename (&info);
 204                         ret = -EFAULT;
 205                         if (copy_to_user (&idata->umsdos_dirent, &entry,
 206                                                         sizeof (entry)))
 207                                 break;
 208                         if (copy_to_user (&idata->dos_dirent.d_name,
 209                                                         info.fake.fname,
 210                                                         info.fake.len + 1))
 211                                 break;
 212                         ret = entry.name_len;
 213                         break;
 214                 }
 215                 /* update the original f_pos */
 216                 filp->f_pos = pos;
 217         read_dput:
 218                 d_drop(demd);
 219                 dput(demd);
 220                 goto out;
 221         }
 222         if (cmd == UMSDOS_INIT_EMD) {
 223                 /* #Specification: ioctl / UMSDOS_INIT_EMD
 224                  * The UMSDOS_INIT_EMD command makes sure the EMD
 225                  * exists for a directory. If it does not, it is
 226                  * created. Also, it makes sure the directory function
 227                  * table (struct inode_operations) is set to the UMSDOS
 228                  * semantic. This mean that umssync may be applied to
 229                  * an "opened" msdos directory, and it will change behavior
 230                  * on the fly.
 231                  *
 232                  * Return 0 if success.
 233                  */
 234
 235                 ret = umsdos_make_emd(dentry);
 236 Printk(("UMSDOS_ioctl_dir: INIT_EMD %s/%s, ret=%d\n",
 237 dentry->d_parent->d_name.name, dentry->d_name.name, ret));
 238                 umsdos_setup_dir (dentry);
 239                 goto out;
 240         }
 241
 242         ret = -EFAULT;
 243         if (copy_from_user (&data, idata, sizeof (data)))
 244                 goto out;
 245
 246         if (cmd == UMSDOS_CREAT_EMD) {
 247                 /* #Specification: ioctl / UMSDOS_CREAT_EMD
 248                  * The umsdos_dirent field of the struct umsdos_ioctl is used
 249                  * as is to create a new entry in the EMD of the directory.
 250                  * The DOS directory is not modified.
 251                  * No validation is done (yet).
 252                  *
 253                  * Return 0 if success.
 254                  */
 255                 struct umsdos_info info;
 256
 257                 /* This makes sure info.entry and info in general
 258                  * is correctly initialised
 259                  */
 260                 memcpy (&info.entry, &data.umsdos_dirent,
 261                         sizeof (data.umsdos_dirent));
 262                 umsdos_parse (data.umsdos_dirent.name
 263                     ,data.umsdos_dirent.name_len, &info);
 264                 ret = umsdos_newentry (dentry, &info);
 265                 goto out;
 266         }
 267         else if (cmd == UMSDOS_RENAME_DOS) {
 268                 struct dentry *old_dentry, *new_dentry;         /* FIXME */
 269
 270                 /* #Specification: ioctl / UMSDOS_RENAME_DOS
 271                  * A file or directory is renamed in a DOS directory
 272                  * (not moved across directory). The source name
 273                  * is in the dos_dirent.name field and the destination
 274                  * is in umsdos_dirent.name field.
 275                  *
 276                  * This ioctl allows umssync to rename a mangled file
 277                  * name before syncing it back in the EMD.
 278                  */
 279                 old_dentry = umsdos_lookup_dentry (dentry,
 280                                                 data.dos_dirent.d_name,
 281                                                 data.dos_dirent.d_reclen ,1);
 282                 ret = PTR_ERR(old_dentry);
 283                 if (IS_ERR(old_dentry))
 284                         goto out;
 285                 new_dentry = umsdos_lookup_dentry (dentry,
 286                                                 data.umsdos_dirent.name,
 287                                                 data.umsdos_dirent.name_len, 1);
 288                 ret = PTR_ERR(new_dentry);
 289                 if (!IS_ERR(new_dentry)) {
 290 printk("umsdos_ioctl: renaming %s/%s to %s/%s\n",
 291 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
 292 new_dentry->d_parent->d_name.name, new_dentry->d_name.name);
 293                         ret = msdos_rename (dir, old_dentry, dir, new_dentry);
 294                         d_drop(new_dentry);
 295                         d_drop(old_dentry);
 296                         dput(new_dentry);
 297                 }
 298                 dput(old_dentry);
 299                 goto out;
 300         }
 301         else if (cmd == UMSDOS_UNLINK_EMD) {
 302                 /* #Specification: ioctl / UMSDOS_UNLINK_EMD
 303                  * The umsdos_dirent field of the struct umsdos_ioctl is used
 304                  * as is to remove an entry from the EMD of the directory.
 305                  * No validation is done (yet). The mode field is used
 306                  * to validate S_ISDIR or S_ISREG.
 307                  *
 308                  * Return 0 if success.
 309                  */
 310                 struct umsdos_info info;
 311
 312                 /* This makes sure info.entry and info in general
 313                  * is correctly initialised
 314                  */
 315                 memcpy (&info.entry, &data.umsdos_dirent,
 316                         sizeof (data.umsdos_dirent));
 317                 umsdos_parse (data.umsdos_dirent.name,
 318                                 data.umsdos_dirent.name_len, &info);
 319                 ret = umsdos_delentry (dentry, &info,
 320                                 S_ISDIR (data.umsdos_dirent.mode));
 321                 if (ret) {
 322                         printk(KERN_WARNING
 323                                 "umsdos_ioctl: delentry %s/%s failed, ret=%d\n",
 324                                 dentry->d_name.name, info.entry.name, ret);
 325                 }
 326                 goto out;
 327         }
 328         else if (cmd == UMSDOS_UNLINK_DOS) {
 329                 struct dentry *temp;
 330
 331                 /* #Specification: ioctl / UMSDOS_UNLINK_DOS
 332                  * The dos_dirent field of the struct umsdos_ioctl is used to
 333                  * execute a msdos_unlink operation. The d_name and d_reclen
 334                  * fields are used.
 335                  *
 336                  * Return 0 if success.
 337                  */
 338                 temp = umsdos_lookup_dentry(dentry, data.dos_dirent.d_name,
 339                                                 data.dos_dirent.d_reclen, 1);
 340                 ret = PTR_ERR(temp);
 341                 if (IS_ERR(temp))
 342                         goto out;
 343                 ret = -ENOENT;
 344                 if (temp->d_inode) {
 345                         ret = -EISDIR;
 346                         if (!S_ISDIR(temp->d_inode->i_mode))
 347                                 ret = msdos_unlink (dir, temp);
 348                         if (!ret)
 349                                 d_delete(temp);
 350                 }
 351                 dput (temp);
 352                 goto out;
 353         }
 354         else if (cmd == UMSDOS_RMDIR_DOS) {
 355                 struct dentry *temp;
 356
 357                 /* #Specification: ioctl / UMSDOS_RMDIR_DOS
 358                  * The dos_dirent field of the struct umsdos_ioctl is used to
 359                  * execute a msdos_rmdir operation. The d_name and d_reclen
 360                  * fields are used.
 361                  *
 362                  * Return 0 if success.
 363                  */
 364                 temp = umsdos_lookup_dentry(dentry, data.dos_dirent.d_name,
 365                                             data.dos_dirent.d_reclen, 1);
 366                 ret = PTR_ERR(temp);
 367                 if (IS_ERR(temp))
 368                         goto out;
 369                 ret = -ENOENT;
 370                 if (temp->d_inode) {
 371                         ret = -ENOTDIR;
 372                         if (S_ISDIR(temp->d_inode->i_mode))
 373                                 ret = msdos_rmdir (dir, temp);
 374                         if (!ret)
 375                                 d_delete(temp);
 376                 }
 377                 dput (temp);
 378                 goto out;
 379
 380         } else if (cmd == UMSDOS_STAT_DOS) {
 381                 /* #Specification: ioctl / UMSDOS_STAT_DOS
 382                  * The dos_dirent field of the struct umsdos_ioctl is
 383                  * used to execute a stat operation in the DOS directory.
 384                  * The d_name and d_reclen fields are used.
 385                  *
 386                  * The following field of umsdos_ioctl.stat are filled.
 387                  *
 388                  * st_ino,st_mode,st_size,st_atime,st_mtime,st_ctime,
 389                  * Return 0 if success.
 390                  */
 391                 struct dentry *dret;
 392                 struct inode *inode;
 393
 394                 dret = umsdos_lookup_dentry(dentry, data.dos_dirent.d_name,
 395                                             data.dos_dirent.d_reclen, 1);
 396                 ret = PTR_ERR(dret);
 397                 if (IS_ERR(dret))
 398                         goto out;
 399                 ret = -ENOENT;
 400                 inode = dret->d_inode;
 401                 if (inode) {
 402                         data.stat.st_ino = inode->i_ino;
 403                         data.stat.st_mode = inode->i_mode;
 404                         data.stat.st_size = inode->i_size;
 405                         data.stat.st_atime = inode->i_atime;
 406                         data.stat.st_ctime = inode->i_ctime;
 407                         data.stat.st_mtime = inode->i_mtime;
 408                         ret = -EFAULT;
 409                         if (!copy_to_user (&idata->stat, &data.stat,
 410                                                 sizeof (data.stat)))
 411                                 ret = 0;
 412                 }
 413                 dput(dret);
 414                 goto out;
 415         }
 416         else if (cmd == UMSDOS_DOS_SETUP) {
 417                 /* #Specification: ioctl / UMSDOS_DOS_SETUP
 418                  * The UMSDOS_DOS_SETUP ioctl allow changing the
 419                  * default permission of the MS-DOS filesystem driver
 420                  * on the fly.  The MS-DOS driver applies global permissions
 421                  * to every file and directory. Normally these permissions
 422                  * are controlled by a mount option. This is not
 423                  * available for root partition, so a special utility
 424                  * (umssetup) is provided to do this, normally in
 425                  * /etc/rc.local.
 426                  *
 427                  * Be aware that this applies ONLY to MS-DOS directories
 428                  * (those without EMD --linux-.---). Umsdos directory
 429                  * have independent (standard) permission for each
 430                  * and every file.
 431                  *
 432                  * The field umsdos_dirent provide the information needed.
 433                  * umsdos_dirent.uid and gid sets the owner and group.
 434                  * umsdos_dirent.mode set the permissions flags.
 435                  */
 436                 dir->i_sb->u.msdos_sb.options.fs_uid = data.umsdos_dirent.uid;
 437                 dir->i_sb->u.msdos_sb.options.fs_gid = data.umsdos_dirent.gid;
 438                 dir->i_sb->u.msdos_sb.options.fs_fmask =
 439                         dir->i_sb->u.msdos_sb.options.fs_dmask =
 440                                 data.umsdos_dirent.mode;
 441                 ret = 0;
 442         }
 443 out:
 444         Printk (("ioctl %d, returning %d\n", cmd, ret));
 445         return ret;
 446 }