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