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