lib/vfs/interface.c

   1 /*
   2    Virtual File System: interface functions
   3
   4    Copyright (C) 2011
   5    The Free Software Foundation, Inc.
   6
   7    Written by:
   8    Slava Zanko <slavazanko@gmail.com>, 2011
   9
  10    This file is part of the Midnight Commander.
  11
  12    The Midnight Commander is free software: you can redistribute it
  13    and/or modify it under the terms of the GNU General Public License as
  14    published by the Free Software Foundation, either version 3 of the License,
  15    or (at your option) any later version.
  16
  17    The Midnight Commander is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24  */
  25
  26 /**
  27  * \file
  28  * \brief Source: Virtual File System: path handlers
  29  * \author Slava Zanko
  30  * \date 2011
  31  */
  32
  33
  34 #include <config.h>
  35
  36 #include <stdio.h>
  37 #include <stdlib.h>             /* For atol() */
  38 #include <stdarg.h>
  39 #include <string.h>
  40 #include <errno.h>
  41 #include <sys/types.h>
  42 #include <signal.h>
  43 #include <ctype.h>              /* is_digit() */
  44 #include <fcntl.h>
  45 #include <sys/stat.h>
  46 #include <unistd.h>
  47 #include <dirent.h>
  48
  49 #include "lib/global.h"
  50
  51 #include "lib/widget.h"         /* message() */
  52 #include "lib/strutil.h"        /* str_crt_conv_from() */
  53
  54 #include "vfs.h"
  55 #include "utilvfs.h"
  56 #include "path.h"
  57 #include "gc.h"
  58
  59 extern GString *vfs_str_buffer;
  60 extern struct vfs_class *current_vfs;
  61
  62 /*** global variables ****************************************************************************/
  63
  64 struct dirent *mc_readdir_result = NULL;
  65
  66 /*** file scope macro definitions ****************************************************************/
  67
  68 /*** file scope type declarations ****************************************************************/
  69
  70 /*** file scope variables ************************************************************************/
  71
  72 /*** file scope functions ************************************************************************/
  73 /* --------------------------------------------------------------------------------------------- */
  74
  75 static char *
  76 mc_def_getlocalcopy (const char *filename)
  77 {
  78     char *tmp;
  79     int fdin, fdout;
  80     ssize_t i;
  81     char buffer[8192];
  82     struct stat mystat;
  83     vfs_path_t *vpath = vfs_path_from_str (filename);
  84
  85     fdin = mc_open (filename, O_RDONLY | O_LINEAR);
  86     if (fdin == -1)
  87         return NULL;
  88
  89     fdout = vfs_mkstemps (&tmp, "vfs", filename);
  90
  91     if (fdout == -1)
  92         goto fail;
  93     while ((i = mc_read (fdin, buffer, sizeof (buffer))) > 0)
  94     {
  95         if (write (fdout, buffer, i) != i)
  96             goto fail;
  97     }
  98     if (i == -1)
  99         goto fail;
 100     i = mc_close (fdin);
 101     fdin = -1;
 102     if (i == -1)
 103         goto fail;
 104     if (close (fdout) == -1)
 105     {
 106         fdout = -1;
 107         goto fail;
 108     }
 109
 110     if (mc_stat (vpath, &mystat) != -1)
 111         chmod (tmp, mystat.st_mode);
 112     vfs_path_free (vpath);
 113
 114     return tmp;
 115
 116   fail:
 117     vfs_path_free (vpath);
 118     if (fdout != -1)
 119         close (fdout);
 120     if (fdin != -1)
 121         mc_close (fdin);
 122     g_free (tmp);
 123     return NULL;
 124 }
 125
 126 /* --------------------------------------------------------------------------------------------- */
 127
 128 static int
 129 mc_def_ungetlocalcopy (struct vfs_class *vfs, const char *filename,
 130                        const char *local, int has_changed)
 131 {
 132     int fdin = -1, fdout = -1;
 133     if (has_changed)
 134     {
 135         char buffer[8192];
 136         ssize_t i;
 137
 138         if (!vfs->write)
 139             goto failed;
 140
 141         fdin = open (local, O_RDONLY);
 142         if (fdin == -1)
 143             goto failed;
 144         fdout = mc_open (filename, O_WRONLY | O_TRUNC);
 145         if (fdout == -1)
 146             goto failed;
 147         while ((i = read (fdin, buffer, sizeof (buffer))) > 0)
 148             if (mc_write (fdout, buffer, (size_t) i) != i)
 149                 goto failed;
 150         if (i == -1)
 151             goto failed;
 152
 153         if (close (fdin) == -1)
 154         {
 155             fdin = -1;
 156             goto failed;
 157         }
 158         fdin = -1;
 159         if (mc_close (fdout) == -1)
 160         {
 161             fdout = -1;
 162             goto failed;
 163         }
 164     }
 165     unlink (local);
 166     return 0;
 167
 168   failed:
 169     message (D_ERROR, _("Changes to file lost"), "%s", filename);
 170     if (fdout != -1)
 171         mc_close (fdout);
 172     if (fdin != -1)
 173         close (fdin);
 174     unlink (local);
 175     return -1;
 176 }
 177
 178 /* --------------------------------------------------------------------------------------------- */
 179 /*** public functions ****************************************************************************/
 180 /* --------------------------------------------------------------------------------------------- */
 181
 182 int
 183 mc_open (const char *filename, int flags, ...)
 184 {
 185     int mode = 0, result = -1;
 186     vfs_path_t *vpath;
 187     vfs_path_element_t *path_element;
 188
 189     vpath = vfs_path_from_str (filename);
 190     if (vpath == NULL)
 191         return -1;
 192
 193     /* Get the mode flag */
 194     if (flags & O_CREAT)
 195     {
 196         va_list ap;
 197         va_start (ap, flags);
 198         mode = va_arg (ap, int);
 199         va_end (ap);
 200     }
 201
 202     path_element = vfs_path_get_by_index (vpath, -1);
 203     if (vfs_path_element_valid (path_element) && path_element->class->open != NULL)
 204     {
 205         void *info;
 206         /* open must be supported */
 207         info = path_element->class->open (vpath, flags, mode);
 208         if (info == NULL)
 209             errno = vfs_ferrno (path_element->class);
 210         else
 211             result = vfs_new_handle (path_element->class, info);
 212     }
 213     else
 214         errno = -EOPNOTSUPP;
 215
 216     vfs_path_free (vpath);
 217     return result;
 218 }
 219
 220 /* --------------------------------------------------------------------------------------------- */
 221
 222 /* *INDENT-OFF* */
 223
 224 #define MC_NAMEOP(name, inarg, callarg) \
 225 int mc_##name inarg \
 226 { \
 227     int result; \
 228     vfs_path_element_t *path_element; \
 229 \
 230     if (vpath == NULL) \
 231         return -1; \
 232 \
 233     path_element = vfs_path_get_by_index (vpath, -1); \
 234     if (!vfs_path_element_valid (path_element)) \
 235     { \
 236         return -1; \
 237     } \
 238 \
 239     result = path_element->class->name != NULL ? path_element->class->name callarg : -1; \
 240     if (result == -1) \
 241         errno = path_element->class->name != NULL ? vfs_ferrno (path_element->class) : E_NOTSUPP; \
 242     return result; \
 243 }
 244
 245 MC_NAMEOP (chmod, (const vfs_path_t *vpath, mode_t mode), (vpath, mode))
 246 MC_NAMEOP (chown, (const vfs_path_t *vpath, uid_t owner, gid_t group), (vpath, owner, group))
 247 MC_NAMEOP (utime, (const vfs_path_t *vpath, struct utimbuf * times), (vpath, times))
 248 MC_NAMEOP (readlink, (const vfs_path_t *vpath, char *buf, size_t bufsiz), (vpath, buf, bufsiz))
 249 MC_NAMEOP (unlink, (const vfs_path_t *vpath), (vpath))
 250 MC_NAMEOP (mkdir, (const vfs_path_t *vpath, mode_t mode), (vpath, mode))
 251 MC_NAMEOP (rmdir, (const vfs_path_t *vpath), (vpath))
 252 MC_NAMEOP (mknod, (const vfs_path_t *vpath, mode_t mode, dev_t dev), (vpath, mode, dev))
 253
 254 /* *INDENT-ON* */
 255
 256 /* --------------------------------------------------------------------------------------------- */
 257
 258 int
 259 mc_symlink (const char *name1, const char *path)
 260 {
 261     int result = -1;
 262     vfs_path_t *vpath1, *vpath2;
 263
 264     vpath1 = vfs_path_from_str (path);
 265     if (vpath1 == NULL)
 266         return -1;
 267
 268     vpath2 = vfs_path_from_str_flags (name1, VPF_NO_CANON);
 269
 270     if (vpath2 != NULL)
 271     {
 272         vfs_path_element_t *path_element = vfs_path_get_by_index (vpath1, -1);
 273         if (vfs_path_element_valid (path_element))
 274         {
 275             result =
 276                 path_element->class->symlink !=
 277                 NULL ? path_element->class->symlink (vpath2, vpath1) : -1;
 278
 279             if (result == -1)
 280                 errno =
 281                     path_element->class->symlink !=
 282                     NULL ? vfs_ferrno (path_element->class) : E_NOTSUPP;
 283         }
 284     }
 285     vfs_path_free (vpath1);
 286     vfs_path_free (vpath2);
 287     return result;
 288 }
 289
 290 /* --------------------------------------------------------------------------------------------- */
 291
 292 /* *INDENT-OFF* */
 293
 294 #define MC_HANDLEOP(name, inarg, callarg) \
 295 ssize_t mc_##name inarg \
 296 { \
 297     struct vfs_class *vfs; \
 298     int result; \
 299     if (handle == -1) \
 300         return -1; \
 301     vfs = vfs_class_find_by_handle (handle); \
 302     if (vfs == NULL) \
 303         return -1; \
 304     result = vfs->name != NULL ? vfs->name callarg : -1; \
 305     if (result == -1) \
 306         errno = vfs->name != NULL ? vfs_ferrno (vfs) : E_NOTSUPP; \
 307     return result; \
 308 }
 309
 310 MC_HANDLEOP (read, (int handle, void *buffer, size_t count), (vfs_class_data_find_by_handle (handle), buffer, count))
 311 MC_HANDLEOP (write, (int handle, const void *buf, size_t nbyte), (vfs_class_data_find_by_handle (handle), buf, nbyte))
 312
 313 /* --------------------------------------------------------------------------------------------- */
 314
 315 #define MC_RENAMEOP(name) \
 316 int mc_##name (const char *fname1, const char *fname2) \
 317 { \
 318     int result; \
 319     vfs_path_t *vpath1, *vpath2; \
 320     vfs_path_element_t *path_element1, *path_element2; \
 321 \
 322     vpath1 = vfs_path_from_str (fname1); \
 323     if (vpath1 == NULL) \
 324         return -1; \
 325 \
 326     vpath2 = vfs_path_from_str (fname2); \
 327     if (vpath2 == NULL) \
 328     { \
 329         vfs_path_free(vpath1); \
 330         return -1; \
 331     }\
 332     path_element1 = vfs_path_get_by_index (vpath1, - 1); \
 333     path_element2 = vfs_path_get_by_index (vpath2, - 1); \
 334 \
 335     if (!vfs_path_element_valid (path_element1) || !vfs_path_element_valid (path_element2) || \
 336         path_element1->class != path_element2->class) \
 337     { \
 338         errno = EXDEV; \
 339         vfs_path_free(vpath1); \
 340         vfs_path_free(vpath2); \
 341         return -1; \
 342     }\
 343 \
 344     result = path_element1->class->name != NULL \
 345         ? path_element1->class->name (vpath1, vpath2) \
 346         : -1; \
 347     if (result == -1) \
 348         errno = path_element1->class->name != NULL ? vfs_ferrno (path_element1->class) : E_NOTSUPP; \
 349     vfs_path_free(vpath1); \
 350     vfs_path_free(vpath2); \
 351     return result; \
 352 }
 353
 354 MC_RENAMEOP (link)
 355 MC_RENAMEOP (rename)
 356
 357 /* *INDENT-ON* */
 358
 359 /* --------------------------------------------------------------------------------------------- */
 360
 361 int
 362 mc_ctl (int handle, int ctlop, void *arg)
 363 {
 364     struct vfs_class *vfs = vfs_class_find_by_handle (handle);
 365
 366     if (vfs == NULL)
 367         return 0;
 368
 369     return vfs->ctl ? (*vfs->ctl) (vfs_class_data_find_by_handle (handle), ctlop, arg) : 0;
 370 }
 371
 372 /* --------------------------------------------------------------------------------------------- */
 373
 374 int
 375 mc_setctl (const vfs_path_t * vpath, int ctlop, void *arg)
 376 {
 377     int result = -1;
 378
 379     vfs_path_element_t *path_element;
 380
 381     if (vpath == NULL)
 382         vfs_die ("You don't want to pass NULL to mc_setctl.");
 383
 384     path_element = vfs_path_get_by_index (vpath, -1);
 385     if (vfs_path_element_valid (path_element))
 386         result =
 387             path_element->class->setctl != NULL ? path_element->class->setctl (vpath,
 388                                                                                ctlop, arg) : 0;
 389
 390     return result;
 391 }
 392
 393 /* --------------------------------------------------------------------------------------------- */
 394
 395 int
 396 mc_close (int handle)
 397 {
 398     struct vfs_class *vfs;
 399     int result;
 400
 401     if (handle == -1 || !vfs_class_data_find_by_handle (handle))
 402         return -1;
 403
 404     vfs = vfs_class_find_by_handle (handle);
 405     if (vfs == NULL)
 406         return -1;
 407
 408     if (handle < 3)
 409         return close (handle);
 410
 411     if (!vfs->close)
 412         vfs_die ("VFS must support close.\n");
 413     result = (*vfs->close) (vfs_class_data_find_by_handle (handle));
 414     vfs_free_handle (handle);
 415     if (result == -1)
 416         errno = vfs_ferrno (vfs);
 417
 418     return result;
 419 }
 420
 421 /* --------------------------------------------------------------------------------------------- */
 422
 423 DIR *
 424 mc_opendir (const vfs_path_t * vpath)
 425 {
 426     int handle, *handlep;
 427     void *info;
 428     vfs_path_element_t *path_element;
 429
 430     if (vpath == NULL)
 431         return NULL;
 432
 433     path_element = vfs_path_get_by_index (vpath, -1);
 434
 435     if (!vfs_path_element_valid (path_element))
 436     {
 437         errno = E_NOTSUPP;
 438         return NULL;
 439     }
 440
 441     info = path_element->class->opendir ? (*path_element->class->opendir) (vpath) : NULL;
 442
 443     if (info == NULL)
 444     {
 445         errno = path_element->class->opendir ? vfs_ferrno (path_element->class) : E_NOTSUPP;
 446         return NULL;
 447     }
 448
 449     path_element->dir.info = info;
 450
 451     path_element->dir.converter =
 452         (path_element->encoding !=
 453          NULL) ? str_crt_conv_from (path_element->encoding) : str_cnv_from_term;
 454     if (path_element->dir.converter == INVALID_CONV)
 455         path_element->dir.converter = str_cnv_from_term;
 456
 457     handle = vfs_new_handle (path_element->class, vfs_path_element_clone (path_element));
 458
 459     handlep = g_new (int, 1);
 460     *handlep = handle;
 461     return (DIR *) handlep;
 462 }
 463
 464 /* --------------------------------------------------------------------------------------------- */
 465
 466 struct dirent *
 467 mc_readdir (DIR * dirp)
 468 {
 469     int handle;
 470     struct vfs_class *vfs;
 471     struct dirent *entry = NULL;
 472     vfs_path_element_t *vfs_path_element;
 473     estr_t state;
 474
 475     if (!mc_readdir_result)
 476     {
 477         /* We can't just allocate struct dirent as (see man dirent.h)
 478          * struct dirent has VERY nonnaive semantics of allocating
 479          * d_name in it. Moreover, linux's glibc-2.9 allocates dirents _less_,
 480          * than 'sizeof (struct dirent)' making full bitwise (sizeof dirent) copy
 481          * heap corrupter. So, allocate longliving dirent with at least
 482          * (MAXNAMLEN + 1) for d_name in it.
 483          * Strictly saying resulting dirent is unusable as we don't adjust internal
 484          * structures, holding dirent size. But we don't use it in libc infrastructure.
 485          * TODO: to make simpler homemade dirent-alike structure.
 486          */
 487         mc_readdir_result = (struct dirent *) g_malloc (sizeof (struct dirent) + MAXNAMLEN + 1);
 488     }
 489
 490     if (!dirp)
 491     {
 492         errno = EFAULT;
 493         return NULL;
 494     }
 495     handle = *(int *) dirp;
 496
 497     vfs = vfs_class_find_by_handle (handle);
 498     if (vfs == NULL)
 499         return NULL;
 500
 501     vfs_path_element = vfs_class_data_find_by_handle (handle);
 502     if (vfs->readdir)
 503     {
 504         entry = (*vfs->readdir) (vfs_path_element->dir.info);
 505         if (entry == NULL)
 506             return NULL;
 507         g_string_set_size (vfs_str_buffer, 0);
 508         state =
 509             str_vfs_convert_from (vfs_path_element->dir.converter, entry->d_name, vfs_str_buffer);
 510         mc_readdir_result->d_ino = entry->d_ino;
 511         g_strlcpy (mc_readdir_result->d_name, vfs_str_buffer->str, MAXNAMLEN + 1);
 512     }
 513     if (entry == NULL)
 514         errno = vfs->readdir ? vfs_ferrno (vfs) : E_NOTSUPP;
 515     return (entry != NULL) ? mc_readdir_result : NULL;
 516 }
 517
 518 /* --------------------------------------------------------------------------------------------- */
 519
 520 int
 521 mc_closedir (DIR * dirp)
 522 {
 523     int handle = *(int *) dirp;
 524     struct vfs_class *vfs;
 525     int result = -1;
 526
 527     vfs = vfs_class_find_by_handle (handle);
 528     if (vfs != NULL)
 529     {
 530         vfs_path_element_t *vfs_path_element;
 531         vfs_path_element = vfs_class_data_find_by_handle (handle);
 532         if (vfs_path_element->dir.converter != str_cnv_from_term)
 533         {
 534             str_close_conv (vfs_path_element->dir.converter);
 535             vfs_path_element->dir.converter = INVALID_CONV;
 536         }
 537
 538         result = vfs->closedir ? (*vfs->closedir) (vfs_path_element->dir.info) : -1;
 539         vfs_free_handle (handle);
 540         vfs_path_element_free (vfs_path_element);
 541     }
 542     g_free (dirp);
 543     return result;
 544 }
 545
 546 /* --------------------------------------------------------------------------------------------- */
 547
 548 int
 549 mc_stat (const vfs_path_t * vpath, struct stat *buf)
 550 {
 551     int result = -1;
 552     vfs_path_element_t *path_element;
 553
 554     if (vpath == NULL)
 555         return -1;
 556
 557     path_element = vfs_path_get_by_index (vpath, -1);
 558
 559     if (vfs_path_element_valid (path_element))
 560     {
 561         result = path_element->class->stat ? (*path_element->class->stat) (vpath, buf) : -1;
 562         if (result == -1)
 563             errno = path_element->class->name ? vfs_ferrno (path_element->class) : E_NOTSUPP;
 564     }
 565
 566     return result;
 567 }
 568
 569 /* --------------------------------------------------------------------------------------------- */
 570
 571 int
 572 mc_lstat (const vfs_path_t * vpath, struct stat *buf)
 573 {
 574     int result = -1;
 575     vfs_path_element_t *path_element;
 576
 577     if (vpath == NULL)
 578         return -1;
 579
 580     path_element = vfs_path_get_by_index (vpath, -1);
 581
 582     if (vfs_path_element_valid (path_element))
 583     {
 584         result = path_element->class->lstat ? (*path_element->class->lstat) (vpath, buf) : -1;
 585         if (result == -1)
 586             errno = path_element->class->name ? vfs_ferrno (path_element->class) : E_NOTSUPP;
 587     }
 588
 589     return result;
 590 }
 591
 592 /* --------------------------------------------------------------------------------------------- */
 593
 594 int
 595 mc_fstat (int handle, struct stat *buf)
 596 {
 597     struct vfs_class *vfs;
 598     int result;
 599
 600     if (handle == -1)
 601         return -1;
 602
 603     vfs = vfs_class_find_by_handle (handle);
 604     if (vfs == NULL)
 605         return -1;
 606
 607     result = vfs->fstat ? (*vfs->fstat) (vfs_class_data_find_by_handle (handle), buf) : -1;
 608     if (result == -1)
 609         errno = vfs->name ? vfs_ferrno (vfs) : E_NOTSUPP;
 610     return result;
 611 }
 612
 613 /* --------------------------------------------------------------------------------------------- */
 614 /**
 615  * Return current directory. If it's local, reread the current directory
 616  * from the OS. Put directory to the provided buffer.
 617  */
 618
 619 char *
 620 mc_get_current_wd (char *buffer, size_t size)
 621 {
 622     char *cwd = _vfs_get_cwd ();
 623
 624     g_strlcpy (buffer, cwd, size);
 625     g_free (cwd);
 626
 627     return buffer;
 628 }
 629
 630 /* --------------------------------------------------------------------------------------------- */
 631
 632 char *
 633 mc_getlocalcopy (const char *pathname)
 634 {
 635     char *result = NULL;
 636     vfs_path_t *vpath;
 637     vfs_path_element_t *path_element;
 638
 639     vpath = vfs_path_from_str (pathname);
 640     if (vpath == NULL)
 641         return NULL;
 642
 643     path_element = vfs_path_get_by_index (vpath, -1);
 644
 645     if (vfs_path_element_valid (path_element))
 646     {
 647         result = path_element->class->getlocalcopy != NULL ?
 648             path_element->class->getlocalcopy (vpath) : mc_def_getlocalcopy (pathname);
 649         if (result == NULL)
 650             errno = vfs_ferrno (path_element->class);
 651     }
 652     vfs_path_free (vpath);
 653     return result;
 654 }
 655
 656 /* --------------------------------------------------------------------------------------------- */
 657
 658 int
 659 mc_ungetlocalcopy (const char *pathname, const char *local, int has_changed)
 660 {
 661     int return_value = -1;
 662     vfs_path_t *vpath;
 663     vfs_path_element_t *path_element;
 664
 665     vpath = vfs_path_from_str (pathname);
 666     if (vpath == NULL)
 667         return -1;
 668
 669     path_element = vfs_path_get_by_index (vpath, -1);
 670
 671     if (vfs_path_element_valid (path_element))
 672     {
 673         return_value = path_element->class->ungetlocalcopy != NULL ?
 674             path_element->class->ungetlocalcopy (vpath, local,
 675                                                  has_changed) :
 676             mc_def_ungetlocalcopy (path_element->class, path_element->path, local, has_changed);
 677     }
 678     vfs_path_free (vpath);
 679     return return_value;
 680 }
 681
 682 /* --------------------------------------------------------------------------------------------- */
 683 /**
 684  * VFS chdir.
 685  *
 686  * @param vpath VFS-path
 687  *
 688  * @return 0 on success, -1 on failure.
 689  */
 690
 691 int
 692 mc_chdir (const vfs_path_t * vpath)
 693 {
 694     struct vfs_class *old_vfs;
 695     vfsid old_vfsid;
 696     int result;
 697     vfs_path_element_t *path_element;
 698
 699     if (vpath == NULL)
 700         return -1;
 701
 702     path_element = vfs_path_get_by_index (vpath, -1);
 703
 704     if (!vfs_path_element_valid (path_element) || path_element->class->chdir == NULL)
 705     {
 706         return -1;
 707     }
 708
 709     result = (*path_element->class->chdir) (vpath);
 710
 711     if (result == -1)
 712     {
 713         errno = vfs_ferrno (path_element->class);
 714         return -1;
 715     }
 716
 717     old_vfsid = vfs_getid (vfs_get_raw_current_dir ());
 718     old_vfs = current_vfs;
 719
 720     /* Actually change directory */
 721     vfs_set_raw_current_dir (vfs_path_clone (vpath));
 722     current_vfs = path_element->class;
 723
 724     /* This function uses the new current_dir implicitly */
 725     vfs_stamp_create (old_vfs, old_vfsid);
 726
 727     /* Sometimes we assume no trailing slash on cwd */
 728     path_element = vfs_path_get_by_index (vfs_get_raw_current_dir (), -1);
 729     if (vfs_path_element_valid (path_element) && (*path_element->path != '\0'))
 730     {
 731         char *p;
 732         p = strchr (path_element->path, 0) - 1;
 733         if (*p == PATH_SEP && p > path_element->path)
 734             *p = 0;
 735     }
 736     return 0;
 737 }
 738
 739 /* --------------------------------------------------------------------------------------------- */
 740
 741 off_t
 742 mc_lseek (int fd, off_t offset, int whence)
 743 {
 744     struct vfs_class *vfs;
 745     off_t result;
 746
 747     if (fd == -1)
 748         return -1;
 749
 750     vfs = vfs_class_find_by_handle (fd);
 751     if (vfs == NULL)
 752         return -1;
 753
 754     result = vfs->lseek ? (*vfs->lseek) (vfs_class_data_find_by_handle (fd), offset, whence) : -1;
 755     if (result == -1)
 756         errno = vfs->lseek ? vfs_ferrno (vfs) : E_NOTSUPP;
 757     return result;
 758 }
 759
 760 /* --------------------------------------------------------------------------------------------- */