lib/vfs/interface.c

   1 /*
   2    Virtual File System: interface functions
   3
   4    Copyright (C) 2011-2016
   5    Free Software Foundation, Inc.
   6
   7    Written by:
   8    Slava Zanko <slavazanko@gmail.com>, 2011, 2013
   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 <sys/stat.h>
  45 #include <unistd.h>
  46 #include <dirent.h>
  47 #include <pwd.h>
  48 #include <grp.h>
  49
  50 #include "lib/global.h"
  51
  52 #include "lib/widget.h"         /* message() */
  53 #include "lib/strutil.h"        /* str_crt_conv_from() */
  54 #include "lib/util.h"
  55
  56 #include "vfs.h"
  57 #include "utilvfs.h"
  58 #include "path.h"
  59 #include "gc.h"
  60 #include "xdirentry.h"
  61
  62 /* TODO: move it to separate private .h */
  63 extern GString *vfs_str_buffer;
  64 extern struct vfs_class *current_vfs;
  65 extern struct dirent *mc_readdir_result;
  66
  67 /*** global variables ****************************************************************************/
  68
  69 struct dirent *mc_readdir_result = NULL;
  70
  71 /*** file scope macro definitions ****************************************************************/
  72
  73 /*** file scope type declarations ****************************************************************/
  74
  75 /*** file scope variables ************************************************************************/
  76
  77 /*** file scope functions ************************************************************************/
  78 /* --------------------------------------------------------------------------------------------- */
  79
  80 static vfs_path_t *
  81 mc_def_getlocalcopy (const vfs_path_t * filename_vpath)
  82 {
  83     vfs_path_t *tmp_vpath = NULL;
  84     int fdin, fdout = -1;
  85     ssize_t i;
  86     char buffer[BUF_1K * 8];
  87     struct stat mystat;
  88
  89     fdin = mc_open (filename_vpath, O_RDONLY | O_LINEAR);
  90     if (fdin == -1)
  91         goto fail;
  92
  93     fdout = vfs_mkstemps (&tmp_vpath, "vfs", vfs_path_get_last_path_str (filename_vpath));
  94     if (fdout == -1)
  95         goto fail;
  96
  97     while ((i = mc_read (fdin, buffer, sizeof (buffer))) > 0)
  98     {
  99         if (write (fdout, buffer, i) != i)
 100             goto fail;
 101     }
 102     if (i == -1)
 103         goto fail;
 104     i = mc_close (fdin);
 105     fdin = -1;
 106     if (i == -1)
 107         goto fail;
 108
 109     i = close (fdout);
 110     fdout = -1;
 111     if (i == -1)
 112         goto fail;
 113
 114     if (mc_stat (filename_vpath, &mystat) != -1)
 115         mc_chmod (tmp_vpath, mystat.st_mode);
 116
 117     return tmp_vpath;
 118
 119   fail:
 120     vfs_path_free (tmp_vpath);
 121     if (fdout != -1)
 122         close (fdout);
 123     if (fdin != -1)
 124         mc_close (fdin);
 125     return NULL;
 126 }
 127
 128 /* --------------------------------------------------------------------------------------------- */
 129
 130 static int
 131 mc_def_ungetlocalcopy (const vfs_path_t * filename_vpath,
 132                        const vfs_path_t * local_vpath, gboolean has_changed)
 133 {
 134     int fdin = -1, fdout = -1;
 135     const char *local;
 136
 137     local = vfs_path_get_last_path_str (local_vpath);
 138
 139     if (has_changed)
 140     {
 141         char buffer[BUF_1K * 8];
 142         ssize_t i;
 143
 144         if (vfs_path_get_last_path_vfs (filename_vpath)->write == NULL)
 145             goto failed;
 146
 147         fdin = open (local, O_RDONLY);
 148         if (fdin == -1)
 149             goto failed;
 150         fdout = mc_open (filename_vpath, O_WRONLY | O_TRUNC);
 151         if (fdout == -1)
 152             goto failed;
 153         while ((i = read (fdin, buffer, sizeof (buffer))) > 0)
 154             if (mc_write (fdout, buffer, (size_t) i) != i)
 155                 goto failed;
 156         if (i == -1)
 157             goto failed;
 158
 159         if (close (fdin) == -1)
 160         {
 161             fdin = -1;
 162             goto failed;
 163         }
 164         fdin = -1;
 165         if (mc_close (fdout) == -1)
 166         {
 167             fdout = -1;
 168             goto failed;
 169         }
 170     }
 171     unlink (local);
 172     return 0;
 173
 174   failed:
 175     message (D_ERROR, _("Changes to file lost"), "%s", vfs_path_get_last_path_str (filename_vpath));
 176     if (fdout != -1)
 177         mc_close (fdout);
 178     if (fdin != -1)
 179         close (fdin);
 180     unlink (local);
 181     return -1;
 182 }
 183
 184 /* --------------------------------------------------------------------------------------------- */
 185 /*** public functions ****************************************************************************/
 186 /* --------------------------------------------------------------------------------------------- */
 187
 188 int
 189 mc_open (const vfs_path_t * vpath, int flags, ...)
 190 {
 191     int result = -1;
 192     mode_t mode = 0;
 193     const vfs_path_element_t *path_element;
 194
 195     if (vpath == NULL)
 196         return -1;
 197
 198     /* Get the mode flag */
 199     if (flags & O_CREAT)
 200     {
 201         va_list ap;
 202         va_start (ap, flags);
 203         mode = va_arg (ap, mode_t);
 204         va_end (ap);
 205     }
 206
 207     path_element = vfs_path_get_by_index (vpath, -1);
 208     if (vfs_path_element_valid (path_element) && path_element->class->open != NULL)
 209     {
 210         void *info;
 211         /* open must be supported */
 212         info = path_element->class->open (vpath, flags, mode);
 213         if (info == NULL)
 214             errno = vfs_ferrno (path_element->class);
 215         else
 216             result = vfs_new_handle (path_element->class, info);
 217     }
 218     else
 219         errno = -EOPNOTSUPP;
 220
 221     return result;
 222 }
 223
 224 /* --------------------------------------------------------------------------------------------- */
 225
 226 /* *INDENT-OFF* */
 227
 228 #define MC_NAMEOP(name, inarg, callarg) \
 229 int mc_##name inarg \
 230 { \
 231     int result; \
 232     const vfs_path_element_t *path_element; \
 233 \
 234     if (vpath == NULL) \
 235         return -1; \
 236 \
 237     path_element = vfs_path_get_by_index (vpath, -1); \
 238     if (!vfs_path_element_valid (path_element)) \
 239     { \
 240         return -1; \
 241     } \
 242 \
 243     result = path_element->class->name != NULL ? path_element->class->name callarg : -1; \
 244     if (result == -1) \
 245         errno = path_element->class->name != NULL ? vfs_ferrno (path_element->class) : E_NOTSUPP; \
 246     return result; \
 247 }
 248
 249 MC_NAMEOP (chmod, (const vfs_path_t *vpath, mode_t mode), (vpath, mode))
 250 MC_NAMEOP (chown, (const vfs_path_t *vpath, uid_t owner, gid_t group), (vpath, owner, group))
 251 MC_NAMEOP (utime, (const vfs_path_t *vpath, struct utimbuf * times), (vpath, times))
 252 MC_NAMEOP (readlink, (const vfs_path_t *vpath, char *buf, size_t bufsiz), (vpath, buf, bufsiz))
 253 MC_NAMEOP (unlink, (const vfs_path_t *vpath), (vpath))
 254 MC_NAMEOP (mkdir, (const vfs_path_t *vpath, mode_t mode), (vpath, mode))
 255 MC_NAMEOP (rmdir, (const vfs_path_t *vpath), (vpath))
 256 MC_NAMEOP (mknod, (const vfs_path_t *vpath, mode_t mode, dev_t dev), (vpath, mode, dev))
 257
 258 /* *INDENT-ON* */
 259
 260 /* --------------------------------------------------------------------------------------------- */
 261
 262 int
 263 mc_symlink (const vfs_path_t * vpath1, const vfs_path_t * vpath2)
 264 {
 265     int result = -1;
 266
 267     if (vpath1 == NULL)
 268         return -1;
 269
 270     if (vpath1 != NULL)
 271     {
 272         const vfs_path_element_t *path_element;
 273
 274         path_element = vfs_path_get_by_index (vpath2, -1);
 275         if (vfs_path_element_valid (path_element))
 276         {
 277             result =
 278                 path_element->class->symlink != NULL ?
 279                 path_element->class->symlink (vpath1, vpath2) : -1;
 280
 281             if (result == -1)
 282                 errno =
 283                     path_element->class->symlink != NULL ?
 284                     vfs_ferrno (path_element->class) : E_NOTSUPP;
 285         }
 286     }
 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 vfs_path_t *vpath1, const vfs_path_t *vpath2) \
 317 { \
 318     int result; \
 319     const vfs_path_element_t *path_element1; \
 320     const vfs_path_element_t *path_element2; \
 321 \
 322     if (vpath1 == NULL || vpath2 == NULL) \
 323         return -1; \
 324 \
 325     path_element1 = vfs_path_get_by_index (vpath1, (-1)); \
 326     path_element2 = vfs_path_get_by_index (vpath2, (-1)); \
 327 \
 328     if (!vfs_path_element_valid (path_element1) || !vfs_path_element_valid (path_element2) || \
 329         path_element1->class != path_element2->class) \
 330     { \
 331         errno = EXDEV; \
 332         return -1; \
 333     }\
 334 \
 335     result = path_element1->class->name != NULL \
 336         ? path_element1->class->name (vpath1, vpath2) \
 337         : -1; \
 338     if (result == -1) \
 339         errno = path_element1->class->name != NULL ? vfs_ferrno (path_element1->class) : E_NOTSUPP; \
 340     return result; \
 341 }
 342
 343 MC_RENAMEOP (link)
 344 MC_RENAMEOP (rename)
 345
 346 /* *INDENT-ON* */
 347
 348 /* --------------------------------------------------------------------------------------------- */
 349
 350 int
 351 mc_ctl (int handle, int ctlop, void *arg)
 352 {
 353     struct vfs_class *vfs = vfs_class_find_by_handle (handle);
 354
 355     if (vfs == NULL)
 356         return 0;
 357
 358     return vfs->ctl ? (*vfs->ctl) (vfs_class_data_find_by_handle (handle), ctlop, arg) : 0;
 359 }
 360
 361 /* --------------------------------------------------------------------------------------------- */
 362
 363 int
 364 mc_setctl (const vfs_path_t * vpath, int ctlop, void *arg)
 365 {
 366     int result = -1;
 367     const vfs_path_element_t *path_element;
 368
 369     if (vpath == NULL)
 370         vfs_die ("You don't want to pass NULL to mc_setctl.");
 371
 372     path_element = vfs_path_get_by_index (vpath, -1);
 373     if (vfs_path_element_valid (path_element))
 374         result =
 375             path_element->class->setctl != NULL ? path_element->class->setctl (vpath,
 376                                                                                ctlop, arg) : 0;
 377
 378     return result;
 379 }
 380
 381 /* --------------------------------------------------------------------------------------------- */
 382
 383 int
 384 mc_close (int handle)
 385 {
 386     struct vfs_class *vfs;
 387     int result;
 388
 389     if (handle == -1 || !vfs_class_data_find_by_handle (handle))
 390         return -1;
 391
 392     vfs = vfs_class_find_by_handle (handle);
 393     if (vfs == NULL)
 394         return -1;
 395
 396     if (handle < 3)
 397         return close (handle);
 398
 399     if (!vfs->close)
 400         vfs_die ("VFS must support close.\n");
 401     result = (*vfs->close) (vfs_class_data_find_by_handle (handle));
 402     vfs_free_handle (handle);
 403     if (result == -1)
 404         errno = vfs_ferrno (vfs);
 405
 406     return result;
 407 }
 408
 409 /* --------------------------------------------------------------------------------------------- */
 410
 411 DIR *
 412 mc_opendir (const vfs_path_t * vpath)
 413 {
 414     int handle, *handlep;
 415     void *info;
 416     vfs_path_element_t *path_element;
 417
 418     if (vpath == NULL)
 419         return NULL;
 420
 421     path_element = (vfs_path_element_t *) vfs_path_get_by_index (vpath, -1);
 422
 423     if (!vfs_path_element_valid (path_element))
 424     {
 425         errno = E_NOTSUPP;
 426         return NULL;
 427     }
 428
 429     info = path_element->class->opendir ? (*path_element->class->opendir) (vpath) : NULL;
 430
 431     if (info == NULL)
 432     {
 433         errno = path_element->class->opendir ? vfs_ferrno (path_element->class) : E_NOTSUPP;
 434         return NULL;
 435     }
 436
 437     path_element->dir.info = info;
 438
 439 #ifdef HAVE_CHARSET
 440     path_element->dir.converter = (path_element->encoding != NULL) ?
 441         str_crt_conv_from (path_element->encoding) : str_cnv_from_term;
 442     if (path_element->dir.converter == INVALID_CONV)
 443         path_element->dir.converter = str_cnv_from_term;
 444 #endif
 445
 446     handle = vfs_new_handle (path_element->class, vfs_path_element_clone (path_element));
 447
 448     handlep = g_new (int, 1);
 449     *handlep = handle;
 450     return (DIR *) handlep;
 451 }
 452
 453 /* --------------------------------------------------------------------------------------------- */
 454
 455 struct dirent *
 456 mc_readdir (DIR * dirp)
 457 {
 458     int handle;
 459     struct vfs_class *vfs;
 460     struct dirent *entry = NULL;
 461     vfs_path_element_t *vfs_path_element;
 462
 463     if (!mc_readdir_result)
 464     {
 465         /* We can't just allocate struct dirent as (see man dirent.h)
 466          * struct dirent has VERY nonnaive semantics of allocating
 467          * d_name in it. Moreover, linux's glibc-2.9 allocates dirents _less_,
 468          * than 'sizeof (struct dirent)' making full bitwise (sizeof dirent) copy
 469          * heap corrupter. So, allocate longliving dirent with at least
 470          * (MAXNAMLEN + 1) for d_name in it.
 471          * Strictly saying resulting dirent is unusable as we don't adjust internal
 472          * structures, holding dirent size. But we don't use it in libc infrastructure.
 473          * TODO: to make simpler homemade dirent-alike structure.
 474          */
 475         mc_readdir_result = (struct dirent *) g_malloc (sizeof (struct dirent) + MAXNAMLEN + 1);
 476     }
 477
 478     if (!dirp)
 479     {
 480         errno = EFAULT;
 481         return NULL;
 482     }
 483     handle = *(int *) dirp;
 484
 485     vfs = vfs_class_find_by_handle (handle);
 486     if (vfs == NULL)
 487         return NULL;
 488
 489     vfs_path_element = vfs_class_data_find_by_handle (handle);
 490     if (vfs->readdir)
 491     {
 492         entry = (*vfs->readdir) (vfs_path_element->dir.info);
 493         if (entry == NULL)
 494             return NULL;
 495
 496         g_string_set_size (vfs_str_buffer, 0);
 497 #ifdef HAVE_CHARSET
 498         str_vfs_convert_from (vfs_path_element->dir.converter, entry->d_name, vfs_str_buffer);
 499 #else
 500         g_string_assign (vfs_str_buffer, entry->d_name);
 501 #endif
 502         mc_readdir_result->d_ino = entry->d_ino;
 503         g_strlcpy (mc_readdir_result->d_name, vfs_str_buffer->str, MAXNAMLEN + 1);
 504     }
 505     if (entry == NULL)
 506         errno = vfs->readdir ? vfs_ferrno (vfs) : E_NOTSUPP;
 507     return (entry != NULL) ? mc_readdir_result : NULL;
 508 }
 509
 510 /* --------------------------------------------------------------------------------------------- */
 511
 512 int
 513 mc_closedir (DIR * dirp)
 514 {
 515     int handle = *(int *) dirp;
 516     struct vfs_class *vfs;
 517     int result = -1;
 518
 519     vfs = vfs_class_find_by_handle (handle);
 520     if (vfs != NULL)
 521     {
 522         vfs_path_element_t *vfs_path_element;
 523         vfs_path_element = vfs_class_data_find_by_handle (handle);
 524
 525 #ifdef HAVE_CHARSET
 526         if (vfs_path_element->dir.converter != str_cnv_from_term)
 527         {
 528             str_close_conv (vfs_path_element->dir.converter);
 529             vfs_path_element->dir.converter = INVALID_CONV;
 530         }
 531 #endif
 532
 533         result = vfs->closedir ? (*vfs->closedir) (vfs_path_element->dir.info) : -1;
 534         vfs_free_handle (handle);
 535         vfs_path_element_free (vfs_path_element);
 536     }
 537     g_free (dirp);
 538     return result;
 539 }
 540
 541 /* --------------------------------------------------------------------------------------------- */
 542
 543 int
 544 mc_stat (const vfs_path_t * vpath, struct stat *buf)
 545 {
 546     int result = -1;
 547     const vfs_path_element_t *path_element;
 548
 549     if (vpath == NULL)
 550         return -1;
 551
 552     path_element = vfs_path_get_by_index (vpath, -1);
 553
 554     if (vfs_path_element_valid (path_element))
 555     {
 556         result = path_element->class->stat ? (*path_element->class->stat) (vpath, buf) : -1;
 557         if (result == -1)
 558             errno = path_element->class->name ? vfs_ferrno (path_element->class) : E_NOTSUPP;
 559     }
 560
 561     return result;
 562 }
 563
 564 /* --------------------------------------------------------------------------------------------- */
 565
 566 int
 567 mc_lstat (const vfs_path_t * vpath, struct stat *buf)
 568 {
 569     int result = -1;
 570     const vfs_path_element_t *path_element;
 571
 572     if (vpath == NULL)
 573         return -1;
 574
 575     path_element = vfs_path_get_by_index (vpath, -1);
 576
 577     if (vfs_path_element_valid (path_element))
 578     {
 579         result = path_element->class->lstat ? (*path_element->class->lstat) (vpath, buf) : -1;
 580         if (result == -1)
 581             errno = path_element->class->name ? vfs_ferrno (path_element->class) : E_NOTSUPP;
 582     }
 583
 584     return result;
 585 }
 586
 587 /* --------------------------------------------------------------------------------------------- */
 588
 589 int
 590 mc_fstat (int handle, struct stat *buf)
 591 {
 592     struct vfs_class *vfs;
 593     int result;
 594
 595     if (handle == -1)
 596         return -1;
 597
 598     vfs = vfs_class_find_by_handle (handle);
 599     if (vfs == NULL)
 600         return -1;
 601
 602     result = vfs->fstat ? (*vfs->fstat) (vfs_class_data_find_by_handle (handle), buf) : -1;
 603     if (result == -1)
 604         errno = vfs->name ? vfs_ferrno (vfs) : E_NOTSUPP;
 605     return result;
 606 }
 607
 608 /* --------------------------------------------------------------------------------------------- */
 609
 610 vfs_path_t *
 611 mc_getlocalcopy (const vfs_path_t * pathname_vpath)
 612 {
 613     vfs_path_t *result = NULL;
 614     const vfs_path_element_t *path_element;
 615
 616     if (pathname_vpath == NULL)
 617         return NULL;
 618
 619     path_element = vfs_path_get_by_index (pathname_vpath, -1);
 620
 621     if (vfs_path_element_valid (path_element))
 622     {
 623         result = path_element->class->getlocalcopy != NULL ?
 624             path_element->class->getlocalcopy (pathname_vpath) :
 625             mc_def_getlocalcopy (pathname_vpath);
 626         if (result == NULL)
 627             errno = vfs_ferrno (path_element->class);
 628     }
 629     return result;
 630 }
 631
 632 /* --------------------------------------------------------------------------------------------- */
 633
 634 int
 635 mc_ungetlocalcopy (const vfs_path_t * pathname_vpath, const vfs_path_t * local_vpath,
 636                    gboolean has_changed)
 637 {
 638     int return_value = -1;
 639     const vfs_path_element_t *path_element;
 640
 641     if (pathname_vpath == NULL)
 642         return -1;
 643
 644     path_element = vfs_path_get_by_index (pathname_vpath, -1);
 645
 646     if (vfs_path_element_valid (path_element))
 647         return_value = path_element->class->ungetlocalcopy != NULL ?
 648             path_element->class->ungetlocalcopy (pathname_vpath, local_vpath, has_changed) :
 649             mc_def_ungetlocalcopy (pathname_vpath, local_vpath, has_changed);
 650
 651     return return_value;
 652 }
 653
 654 /* --------------------------------------------------------------------------------------------- */
 655 /**
 656  * VFS chdir.
 657  *
 658  * @param vpath VFS-path
 659  *
 660  * @return 0 on success, -1 on failure.
 661  */
 662
 663 int
 664 mc_chdir (const vfs_path_t * vpath)
 665 {
 666     struct vfs_class *old_vfs;
 667     vfsid old_vfsid;
 668     int result;
 669     const vfs_path_element_t *path_element;
 670     vfs_path_t *cd_vpath;
 671
 672     if (vpath == NULL)
 673         return -1;
 674
 675     if (vpath->relative)
 676         cd_vpath = vfs_path_to_absolute (vpath);
 677     else
 678         cd_vpath = vfs_path_clone (vpath);
 679
 680     path_element = vfs_path_get_by_index (cd_vpath, -1);
 681
 682     if (!vfs_path_element_valid (path_element) || path_element->class->chdir == NULL)
 683     {
 684         goto error_end;
 685     }
 686
 687     result = (*path_element->class->chdir) (cd_vpath);
 688
 689     if (result == -1)
 690     {
 691         errno = vfs_ferrno (path_element->class);
 692         goto error_end;
 693     }
 694
 695     old_vfsid = vfs_getid (vfs_get_raw_current_dir ());
 696     old_vfs = current_vfs;
 697
 698     /* Actually change directory */
 699     vfs_set_raw_current_dir (cd_vpath);
 700
 701     current_vfs = path_element->class;
 702
 703     /* This function uses the new current_dir implicitly */
 704     vfs_stamp_create (old_vfs, old_vfsid);
 705
 706     /* Sometimes we assume no trailing slash on cwd */
 707     path_element = vfs_path_get_by_index (vfs_get_raw_current_dir (), -1);
 708     if (vfs_path_element_valid (path_element))
 709     {
 710         if (*path_element->path != '\0')
 711         {
 712             char *p;
 713
 714             p = strchr (path_element->path, 0) - 1;
 715             if (IS_PATH_SEP (*p) && p > path_element->path)
 716                 *p = '\0';
 717         }
 718
 719 #ifdef ENABLE_VFS_NET
 720         {
 721             struct vfs_s_super *super;
 722
 723             super = vfs_get_super_by_vpath (vpath);
 724             if (super != NULL && super->path_element != NULL)
 725             {
 726                 g_free (super->path_element->path);
 727                 super->path_element->path = g_strdup (path_element->path);
 728             }
 729         }
 730 #endif /* ENABLE_VFS_NET */
 731     }
 732
 733     return 0;
 734
 735   error_end:
 736     vfs_path_free (cd_vpath);
 737     return -1;
 738 }
 739
 740 /* --------------------------------------------------------------------------------------------- */
 741
 742 off_t
 743 mc_lseek (int fd, off_t offset, int whence)
 744 {
 745     struct vfs_class *vfs;
 746     off_t result;
 747
 748     if (fd == -1)
 749         return -1;
 750
 751     vfs = vfs_class_find_by_handle (fd);
 752     if (vfs == NULL)
 753         return -1;
 754
 755     result = vfs->lseek ? (*vfs->lseek) (vfs_class_data_find_by_handle (fd), offset, whence) : -1;
 756     if (result == -1)
 757         errno = vfs->lseek ? vfs_ferrno (vfs) : E_NOTSUPP;
 758     return result;
 759 }
 760
 761 /* --------------------------------------------------------------------------------------------- */
 762 /* Following code heavily borrows from libiberty, mkstemps.c */
 763 /*
 764  * Arguments:
 765  * pname (output) - pointer to the name of the temp file (needs g_free).
 766  *                  NULL if the function fails.
 767  * prefix - part of the filename before the random part.
 768  *          Prepend $TMPDIR or /tmp if there are no path separators.
 769  * suffix - if not NULL, part of the filename after the random part.
 770  *
 771  * Result:
 772  * handle of the open file or -1 if couldn't open any.
 773  */
 774
 775 int
 776 mc_mkstemps (vfs_path_t ** pname_vpath, const char *prefix, const char *suffix)
 777 {
 778     char *p1, *p2;
 779     int fd;
 780
 781     if (strchr (prefix, PATH_SEP) != NULL)
 782         p1 = g_strdup (prefix);
 783     else
 784     {
 785         /* Add prefix first to find the position of XXXXXX */
 786         p1 = g_build_filename (mc_tmpdir (), prefix, (char *) NULL);
 787     }
 788
 789     p2 = g_strconcat (p1, "XXXXXX", suffix, (char *) NULL);
 790     g_free (p1);
 791
 792     fd = g_mkstemp (p2);
 793     if (fd >= 0)
 794         *pname_vpath = vfs_path_from_str (p2);
 795     else
 796     {
 797         *pname_vpath = NULL;
 798         fd = -1;
 799     }
 800
 801     g_free (p2);
 802
 803     return fd;
 804 }
 805
 806 /* --------------------------------------------------------------------------------------------- */
 807 /**
 808  * Return the directory where mc should keep its temporary files.
 809  * This directory is (in Bourne shell terms) "${TMPDIR=/tmp}/mc-$USER"
 810  * When called the first time, the directory is created if needed.
 811  * The first call should be done early, since we are using fprintf()
 812  * and not message() to report possible problems.
 813  */
 814
 815 const char *
 816 mc_tmpdir (void)
 817 {
 818     static char buffer[64];
 819     static const char *tmpdir = NULL;
 820     const char *sys_tmp;
 821     struct passwd *pwd;
 822     struct stat st;
 823     const char *error = NULL;
 824
 825     /* Check if already correctly initialized */
 826     if (tmpdir && lstat (tmpdir, &st) == 0 && S_ISDIR (st.st_mode) &&
 827         st.st_uid == getuid () && (st.st_mode & 0777) == 0700)
 828         return tmpdir;
 829
 830     sys_tmp = getenv ("TMPDIR");
 831     if (sys_tmp == NULL || !IS_PATH_SEP (sys_tmp[0]))
 832         sys_tmp = TMPDIR_DEFAULT;
 833
 834     pwd = getpwuid (getuid ());
 835
 836     if (pwd)
 837         g_snprintf (buffer, sizeof (buffer), "%s/mc-%s", sys_tmp, pwd->pw_name);
 838     else
 839         g_snprintf (buffer, sizeof (buffer), "%s/mc-%lu", sys_tmp, (unsigned long) getuid ());
 840
 841     canonicalize_pathname (buffer);
 842
 843     /* Try to create directory */
 844     if (mkdir (buffer, S_IRWXU) != 0)
 845     {
 846         if (errno == EEXIST && lstat (buffer, &st) == 0)
 847         {
 848             /* Sanity check for existing directory */
 849             if (!S_ISDIR (st.st_mode))
 850                 error = _("%s is not a directory\n");
 851             else if (st.st_uid != getuid ())
 852                 error = _("Directory %s is not owned by you\n");
 853             else if (((st.st_mode & 0777) != 0700) && (chmod (buffer, 0700) != 0))
 854                 error = _("Cannot set correct permissions for directory %s\n");
 855         }
 856         else
 857         {
 858             fprintf (stderr,
 859                      _("Cannot create temporary directory %s: %s\n"),
 860                      buffer, unix_error_string (errno));
 861             error = "";
 862         }
 863     }
 864
 865     if (error != NULL)
 866     {
 867         int test_fd;
 868         char *fallback_prefix;
 869         gboolean fallback_ok = FALSE;
 870         vfs_path_t *test_vpath;
 871
 872         if (*error)
 873             fprintf (stderr, error, buffer);
 874
 875         /* Test if sys_tmp is suitable for temporary files */
 876         fallback_prefix = g_strdup_printf ("%s/mctest", sys_tmp);
 877         test_fd = mc_mkstemps (&test_vpath, fallback_prefix, NULL);
 878         g_free (fallback_prefix);
 879         if (test_fd != -1)
 880         {
 881             close (test_fd);
 882             test_fd = open (vfs_path_as_str (test_vpath), O_RDONLY);
 883             if (test_fd != -1)
 884             {
 885                 close (test_fd);
 886                 unlink (vfs_path_as_str (test_vpath));
 887                 fallback_ok = TRUE;
 888             }
 889         }
 890
 891         if (fallback_ok)
 892         {
 893             fprintf (stderr, _("Temporary files will be created in %s\n"), sys_tmp);
 894             g_snprintf (buffer, sizeof (buffer), "%s", sys_tmp);
 895             error = NULL;
 896         }
 897         else
 898         {
 899             fprintf (stderr, _("Temporary files will not be created\n"));
 900             g_snprintf (buffer, sizeof (buffer), "%s", "/dev/null/");
 901         }
 902
 903         vfs_path_free (test_vpath);
 904         fprintf (stderr, "%s\n", _("Press any key to continue..."));
 905         getc (stdin);
 906     }
 907
 908     tmpdir = buffer;
 909
 910     if (!error)
 911         g_setenv ("MC_TMPDIR", tmpdir, TRUE);
 912
 913     return tmpdir;
 914 }
 915
 916 /* --------------------------------------------------------------------------------------------- */