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 file new_filp;
  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 / acces
  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
 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                 fill_new_filp(&new_filp, demd);
 175                 new_filp.f_pos = filp->f_pos;
 176                 while (new_filp.f_pos < demd->d_inode->i_size) {
 177                         off_t f_pos = new_filp.f_pos;
 178                         struct umsdos_dirent entry;
 179                         struct umsdos_info info;
 180
 181                         ret = umsdos_emd_dir_readentry (&new_filp, &entry);
 182                         if (ret)
 183                                 break;
 184                         if (entry.name_len <= 0)
 185                                 continue;
 186
 187                         umsdos_parse (entry.name, entry.name_len, &info);
 188                         info.f_pos = f_pos;
 189                         umsdos_manglename (&info);
 190                         ret = -EFAULT;
 191                         if (copy_to_user (&idata->umsdos_dirent, &entry,
 192                                                         sizeof (entry)))
 193                                 break;
 194                         if (copy_to_user (&idata->dos_dirent.d_name,
 195                                                         info.fake.fname,
 196                                                         info.fake.len + 1))
 197                                 break;
 198                         ret = entry.name_len;
 199                         break;
 200                 }
 201                 /* update the original f_pos */
 202                 filp->f_pos = new_filp.f_pos;
 203         read_dput:
 204                 d_drop(demd);
 205                 dput(demd);
 206                 goto out;
 207         }
 208         if (cmd == UMSDOS_INIT_EMD) {
 209                 /* #Specification: ioctl / UMSDOS_INIT_EMD
 210                  * The UMSDOS_INIT_EMD command makes sure the EMD
 211                  * exists for a directory. If it does not, it is
 212                  * created. Also, it makes sure the directory function
 213                  * table (struct inode_operations) is set to the UMSDOS
 214                  * semantic. This mean that umssync may be applied to
 215                  * an "opened" msdos directory, and it will change behavior
 216                  * on the fly.
 217                  *
 218                  * Return 0 if success.
 219                  */
 220
 221                 ret = umsdos_make_emd(dentry);
 222 Printk(("UMSDOS_ioctl_dir: INIT_EMD %s/%s, ret=%d\n",
 223 dentry->d_parent->d_name.name, dentry->d_name.name, ret));
 224                 umsdos_setup_dir (dentry);
 225                 goto out;
 226         }
 227
 228         ret = -EFAULT;
 229         if (copy_from_user (&data, idata, sizeof (data)))
 230                 goto out;
 231
 232         if (cmd == UMSDOS_CREAT_EMD) {
 233                 /* #Specification: ioctl / UMSDOS_CREAT_EMD
 234                  * The umsdos_dirent field of the struct umsdos_ioctl is used
 235                  * as is to create a new entry in the EMD of the directory.
 236                  * The DOS directory is not modified.
 237                  * No validation is done (yet).
 238                  *
 239                  * Return 0 if success.
 240                  */
 241                 struct umsdos_info info;
 242
 243                 /* This makes sure info.entry and info in general
 244                  * is correctly initialised
 245                  */
 246                 memcpy (&info.entry, &data.umsdos_dirent,
 247                         sizeof (data.umsdos_dirent));
 248                 umsdos_parse (data.umsdos_dirent.name
 249                     ,data.umsdos_dirent.name_len, &info);
 250                 ret = umsdos_newentry (dentry, &info);
 251                 goto out;
 252         }
 253         else if (cmd == UMSDOS_RENAME_DOS) {
 254                 struct dentry *old_dentry, *new_dentry;         /* FIXME */
 255
 256                 /* #Specification: ioctl / UMSDOS_RENAME_DOS
 257                  * A file or directory is renamed in a DOS directory
 258                  * (not moved across directory). The source name
 259                  * is in the dos_dirent.name field and the destination
 260                  * is in umsdos_dirent.name field.
 261                  *
 262                  * This ioctl allows umssync to rename a mangled file
 263                  * name before syncing it back in the EMD.
 264                  */
 265                 old_dentry = umsdos_lookup_dentry (dentry,
 266                                                 data.dos_dirent.d_name,
 267                                                 data.dos_dirent.d_reclen ,1);
 268                 ret = PTR_ERR(old_dentry);
 269                 if (IS_ERR(old_dentry))
 270                         goto out;
 271                 new_dentry = umsdos_lookup_dentry (dentry,
 272                                                 data.umsdos_dirent.name,
 273                                                 data.umsdos_dirent.name_len, 1);
 274                 ret = PTR_ERR(new_dentry);
 275                 if (!IS_ERR(new_dentry)) {
 276 printk("umsdos_ioctl: renaming %s/%s to %s/%s\n",
 277 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
 278 new_dentry->d_parent->d_name.name, new_dentry->d_name.name);
 279                         ret = msdos_rename (dir, old_dentry, dir, new_dentry);
 280                         d_drop(new_dentry);
 281                         d_drop(old_dentry);
 282                         dput(new_dentry);
 283                 }
 284                 dput(old_dentry);
 285                 goto out;
 286         }
 287         else if (cmd == UMSDOS_UNLINK_EMD) {
 288                 /* #Specification: ioctl / UMSDOS_UNLINK_EMD
 289                  * The umsdos_dirent field of the struct umsdos_ioctl is used
 290                  * as is to remove an entry from the EMD of the directory.
 291                  * No validation is done (yet). The mode field is used
 292                  * to validate S_ISDIR or S_ISREG.
 293                  *
 294                  * Return 0 if success.
 295                  */
 296                 struct umsdos_info info;
 297
 298                 /* This makes sure info.entry and info in general
 299                  * is correctly initialised
 300                  */
 301                 memcpy (&info.entry, &data.umsdos_dirent,
 302                         sizeof (data.umsdos_dirent));
 303                 umsdos_parse (data.umsdos_dirent.name,
 304                                 data.umsdos_dirent.name_len, &info);
 305                 ret = umsdos_delentry (dentry, &info,
 306                                 S_ISDIR (data.umsdos_dirent.mode));
 307                 if (ret) {
 308                         printk(KERN_WARNING
 309                                 "umsdos_ioctl: delentry %s/%s failed, ret=%d\n",
 310                                 dentry->d_name.name, info.entry.name, ret);
 311                 }
 312                 goto out;
 313         }
 314         else if (cmd == UMSDOS_UNLINK_DOS) {
 315                 struct dentry *temp;
 316
 317                 /* #Specification: ioctl / UMSDOS_UNLINK_DOS
 318                  * The dos_dirent field of the struct umsdos_ioctl is used to
 319                  * execute a msdos_unlink operation. The d_name and d_reclen
 320                  * fields are used.
 321                  *
 322                  * Return 0 if success.
 323                  */
 324                 temp = umsdos_lookup_dentry(dentry, data.dos_dirent.d_name,
 325                                                 data.dos_dirent.d_reclen, 1);
 326                 ret = PTR_ERR(temp);
 327                 if (IS_ERR(temp))
 328                         goto out;
 329                 ret = -ENOENT;
 330                 if (temp->d_inode) {
 331                         ret = -EISDIR;
 332                         if (!S_ISDIR(temp->d_inode->i_mode))
 333                                 ret = msdos_unlink (dir, temp);
 334                         if (!ret)
 335                                 d_delete(temp);
 336                 }
 337                 dput (temp);
 338                 goto out;
 339         }
 340         else if (cmd == UMSDOS_RMDIR_DOS) {
 341                 struct dentry *temp;
 342
 343                 /* #Specification: ioctl / UMSDOS_RMDIR_DOS
 344                  * The dos_dirent field of the struct umsdos_ioctl is used to
 345                  * execute a msdos_rmdir operation. The d_name and d_reclen
 346                  * fields are used.
 347                  *
 348                  * Return 0 if success.
 349                  */
 350                 temp = umsdos_lookup_dentry(dentry, data.dos_dirent.d_name,
 351                                             data.dos_dirent.d_reclen, 1);
 352                 ret = PTR_ERR(temp);
 353                 if (IS_ERR(temp))
 354                         goto out;
 355                 ret = -ENOENT;
 356                 if (temp->d_inode) {
 357                         ret = -ENOTDIR;
 358                         if (S_ISDIR(temp->d_inode->i_mode))
 359                                 ret = msdos_rmdir (dir, temp);
 360                         if (!ret)
 361                                 d_delete(temp);
 362                 }
 363                 dput (temp);
 364                 goto out;
 365
 366         } else if (cmd == UMSDOS_STAT_DOS) {
 367                 /* #Specification: ioctl / UMSDOS_STAT_DOS
 368                  * The dos_dirent field of the struct umsdos_ioctl is
 369                  * used to execute a stat operation in the DOS directory.
 370                  * The d_name and d_reclen fields are used.
 371                  *
 372                  * The following field of umsdos_ioctl.stat are filled.
 373                  *
 374                  * st_ino,st_mode,st_size,st_atime,st_mtime,st_ctime,
 375                  * Return 0 if success.
 376                  */
 377                 struct dentry *dret;
 378                 struct inode *inode;
 379
 380                 dret = umsdos_lookup_dentry(dentry, data.dos_dirent.d_name,
 381                                             data.dos_dirent.d_reclen, 1);
 382                 ret = PTR_ERR(dret);
 383                 if (IS_ERR(dret))
 384                         goto out;
 385                 ret = -ENOENT;
 386                 inode = dret->d_inode;
 387                 if (inode) {
 388                         data.stat.st_ino = inode->i_ino;
 389                         data.stat.st_mode = inode->i_mode;
 390                         data.stat.st_size = inode->i_size;
 391                         data.stat.st_atime = inode->i_atime;
 392                         data.stat.st_ctime = inode->i_ctime;
 393                         data.stat.st_mtime = inode->i_mtime;
 394                         ret = -EFAULT;
 395                         if (!copy_to_user (&idata->stat, &data.stat,
 396                                                 sizeof (data.stat)))
 397                                 ret = 0;
 398                 }
 399                 dput(dret);
 400                 goto out;
 401         }
 402         else if (cmd == UMSDOS_DOS_SETUP) {
 403                 /* #Specification: ioctl / UMSDOS_DOS_SETUP
 404                  * The UMSDOS_DOS_SETUP ioctl allow changing the
 405                  * default permission of the MS-DOS filesystem driver
 406                  * on the fly.  The MS-DOS driver applies global permissions
 407                  * to every file and directory. Normally these permissions
 408                  * are controlled by a mount option. This is not
 409                  * available for root partition, so a special utility
 410                  * (umssetup) is provided to do this, normally in
 411                  * /etc/rc.local.
 412                  *
 413                  * Be aware that this applies ONLY to MS-DOS directories
 414                  * (those without EMD --linux-.---). Umsdos directory
 415                  * have independent (standard) permission for each
 416                  * and every file.
 417                  *
 418                  * The field umsdos_dirent provide the information needed.
 419                  * umsdos_dirent.uid and gid sets the owner and group.
 420                  * umsdos_dirent.mode set the permissions flags.
 421                  */
 422                 dir->i_sb->u.msdos_sb.options.fs_uid = data.umsdos_dirent.uid;
 423                 dir->i_sb->u.msdos_sb.options.fs_gid = data.umsdos_dirent.gid;
 424                 dir->i_sb->u.msdos_sb.options.fs_umask = data.umsdos_dirent.mode;
 425                 ret = 0;
 426         }
 427 out:
 428         Printk (("ioctl %d, returning %d\n", cmd, ret));
 429         return ret;
 430 }