vfs/direntry.c

   1
   2 /** \file
   3  *  \brief Source: directory cache support
   4  *
   5  *  So that you do not have copy of this in each and every filesystem.
   6  *
   7  *  Very loosely based on tar.c from midnight and archives.[ch] from
   8  *  avfs by Miklos Szeredi (mszeredi@inf.bme.hu)
   9  *
  10  *  Unfortunately, I was unable to keep all filesystems
  11  *  uniform. tar-like filesystems use tree structure where each
  12  *  directory has pointers to its subdirectories. We can do this
  13  *  because we have full information about our archive.
  14  *
  15  *  At ftp-like filesystems, situation is a little bit different. When
  16  *  you cd /usr/src/linux/drivers/char, you do _not_ want /usr,
  17  *  /usr/src, /usr/src/linux and /usr/src/linux/drivers to be
  18  *  listed. That means that we do not have complete information, and if
  19  *  /usr is symlink to /4, we will not know. Also we have to time out
  20  *  entries and things would get messy with tree-like approach. So we
  21  *  do different trick: root directory is completely special and
  22  *  completely fake, it contains entries such as 'usr', 'usr/src', ...,
  23  *  and we'll try to use custom find_entry function.
  24  *
  25  *  \author Pavel Machek <pavel@ucw.cz>, distribute under LGPL.
  26  *  \date 1998
  27  *
  28  *  \warning Paths here do _not_ begin with '/', so root directory of
  29  *  archive/site is simply "".
  30  */
  31
  32 #include <config.h>
  33
  34 #include <errno.h>
  35 #include <sys/fcntl.h>
  36 #include <time.h>
  37 #include <sys/time.h>           /* gettimeofday() */
  38
  39 #include "../src/global.h"
  40
  41 #include "../src/tty/tty.h"     /* enable/disable interrupt key */
  42
  43 #include "../src/wtools.h"      /* message() */
  44 #include "../src/main.h"        /* print_vfs_message */
  45
  46 #include "utilvfs.h"
  47 #include "vfs-impl.h"
  48 #include "gc.h"                 /* vfs_rmstamp */
  49 #include "xdirentry.h"
  50
  51 #define CALL(x) if (MEDATA->x) MEDATA->x
  52
  53 static volatile int total_inodes = 0, total_entries = 0;
  54
  55 struct vfs_s_inode *
  56 vfs_s_new_inode (struct vfs_class *me, struct vfs_s_super *super, struct stat *initstat)
  57 {
  58     struct vfs_s_inode *ino;
  59
  60     ino = g_new0 (struct vfs_s_inode, 1);
  61     if (!ino)
  62         return NULL;
  63
  64     if (initstat)
  65         ino->st = *initstat;
  66     ino->super = super;
  67     ino->st.st_nlink = 0;
  68     ino->st.st_ino = MEDATA->inode_counter++;
  69     ino->st.st_dev = MEDATA->rdev;
  70
  71     super->ino_usage++;
  72     total_inodes++;
  73
  74     CALL (init_inode) (me, ino);
  75
  76     return ino;
  77 }
  78
  79 struct vfs_s_entry *
  80 vfs_s_new_entry (struct vfs_class *me, const char *name, struct vfs_s_inode *inode)
  81 {
  82     struct vfs_s_entry *entry;
  83
  84     entry = g_new0 (struct vfs_s_entry, 1);
  85     total_entries++;
  86
  87     if (name)
  88         entry->name = g_strdup (name);
  89
  90     entry->ino = inode;
  91     entry->ino->ent = entry;
  92     CALL (init_entry) (me, entry);
  93
  94     return entry;
  95 }
  96
  97 static void
  98 vfs_s_free_inode (struct vfs_class *me, struct vfs_s_inode *ino)
  99 {
 100     if (!ino)
 101         vfs_die ("Don't pass NULL to me");
 102
 103     /* ==0 can happen if freshly created entry is deleted */
 104     if (ino->st.st_nlink <= 1){
 105         while (ino->subdir){
 106             vfs_s_free_entry (me, ino->subdir);
 107         }
 108
 109         CALL (free_inode) (me, ino);
 110         g_free (ino->linkname);
 111         if (ino->localname){
 112             unlink (ino->localname);
 113             g_free(ino->localname);
 114         }
 115         total_inodes--;
 116         ino->super->ino_usage--;
 117         g_free(ino);
 118     } else ino->st.st_nlink--;
 119 }
 120
 121 void
 122 vfs_s_free_entry (struct vfs_class *me, struct vfs_s_entry *ent)
 123 {
 124     if (ent->prevp){    /* It is possible that we are deleting freshly created entry */
 125         *ent->prevp = ent->next;
 126         if (ent->next)
 127             ent->next->prevp = ent->prevp;
 128     }
 129
 130     g_free (ent->name);
 131     ent->name = NULL;
 132
 133     if (ent->ino){
 134         ent->ino->ent = NULL;
 135         vfs_s_free_inode (me, ent->ino);
 136         ent->ino = NULL;
 137     }
 138
 139     total_entries--;
 140     g_free(ent);
 141 }
 142
 143 void
 144 vfs_s_insert_entry (struct vfs_class *me, struct vfs_s_inode *dir, struct vfs_s_entry *ent)
 145 {
 146     struct vfs_s_entry **ep;
 147
 148     (void) me;
 149
 150     for (ep = &dir->subdir; *ep != NULL; ep = &((*ep)->next))
 151         ;
 152     ent->prevp = ep;
 153     ent->next = NULL;
 154     ent->dir = dir;
 155     *ep = ent;
 156
 157     ent->ino->st.st_nlink++;
 158 }
 159
 160 struct stat *
 161 vfs_s_default_stat (struct vfs_class *me, mode_t mode)
 162 {
 163     static struct stat st;
 164     int myumask;
 165
 166     (void) me;
 167
 168     myumask = umask (022);
 169     umask (myumask);
 170     mode &= ~myumask;
 171
 172     st.st_mode = mode;
 173     st.st_ino = 0;
 174     st.st_dev = 0;
 175     st.st_rdev = 0;
 176     st.st_uid = getuid ();
 177     st.st_gid = getgid ();
 178     st.st_size = 0;
 179     st.st_mtime = st.st_atime = st.st_ctime = time (NULL);
 180
 181     return &st;
 182 }
 183
 184 struct vfs_s_entry *
 185 vfs_s_generate_entry (struct vfs_class *me, const char *name, struct vfs_s_inode *parent, mode_t mode)
 186 {
 187     struct vfs_s_inode *inode;
 188     struct stat *st;
 189
 190     st = vfs_s_default_stat (me, mode);
 191     inode = vfs_s_new_inode (me, parent->super, st);
 192
 193     return vfs_s_new_entry (me, name, inode);
 194 }
 195
 196 /* We were asked to create entries automagically */
 197 static struct vfs_s_entry *
 198 vfs_s_automake (struct vfs_class *me, struct vfs_s_inode *dir, char *path, int flags)
 199 {
 200     struct vfs_s_entry *res;
 201     char *sep = strchr (path, PATH_SEP);
 202
 203     if (sep)
 204             *sep = 0;
 205     res = vfs_s_generate_entry (me, path, dir, flags & FL_MKDIR ? (0777 | S_IFDIR) : 0777);
 206     vfs_s_insert_entry (me, dir, res);
 207
 208     if (sep)
 209             *sep = PATH_SEP;
 210
 211     return res;
 212 }
 213
 214 /* If the entry is a symlink, find the entry for its target */
 215 static struct vfs_s_entry *
 216 vfs_s_resolve_symlink (struct vfs_class *me, struct vfs_s_entry *entry,
 217                        int follow)
 218 {
 219     char *linkname;
 220     char *fullname = NULL;
 221     struct vfs_s_entry *target;
 222
 223     if (follow == LINK_NO_FOLLOW)
 224         return entry;
 225     if (follow == 0)
 226         ERRNOR (ELOOP, NULL);
 227     if (!entry)
 228         ERRNOR (ENOENT, NULL);
 229     if (!S_ISLNK (entry->ino->st.st_mode))
 230         return entry;
 231
 232     linkname = entry->ino->linkname;
 233     if (linkname == NULL)
 234         ERRNOR (EFAULT, NULL);
 235
 236     /* make full path from relative */
 237     if (*linkname != PATH_SEP) {
 238         char *fullpath = vfs_s_fullpath (me, entry->dir);
 239         if (fullpath) {
 240             fullname = g_strconcat (fullpath, "/", linkname, NULL);
 241             linkname = fullname;
 242             g_free (fullpath);
 243         }
 244     }
 245
 246     target =
 247         (MEDATA->find_entry) (me, entry->dir->super->root, linkname,
 248                               follow - 1, 0);
 249     g_free (fullname);
 250     return target;
 251 }
 252
 253 /*
 254  * Follow > 0: follow links, serves as loop protect,
 255  *       == -1: do not follow links
 256  */
 257 static struct vfs_s_entry *
 258 vfs_s_find_entry_tree (struct vfs_class *me, struct vfs_s_inode *root,
 259                        const char *a_path, int follow, int flags)
 260 {
 261     size_t pseg;
 262     struct vfs_s_entry *ent = NULL;
 263     char * const pathref = g_strdup (a_path);
 264     char *path = pathref;
 265
 266     canonicalize_pathname (path);
 267
 268     while (root) {
 269         while (*path == PATH_SEP)       /* Strip leading '/' */
 270             path++;
 271
 272         if (!path[0]) {
 273             g_free (pathref);
 274             return ent;
 275         }
 276
 277         for (pseg = 0; path[pseg] && path[pseg] != PATH_SEP; pseg++);
 278
 279         for (ent = root->subdir; ent != NULL; ent = ent->next)
 280             if (strlen (ent->name) == pseg
 281                 && (!strncmp (ent->name, path, pseg)))
 282                 /* FOUND! */
 283                 break;
 284
 285         if (!ent && (flags & (FL_MKFILE | FL_MKDIR)))
 286             ent = vfs_s_automake (me, root, path, flags);
 287         if (!ent) {
 288             me->verrno = ENOENT;
 289             goto cleanup;
 290         }
 291         path += pseg;
 292         /* here we must follow leading directories always;
 293            only the actual file is optional */
 294         ent =
 295             vfs_s_resolve_symlink (me, ent,
 296                                    strchr (path,
 297                                            PATH_SEP) ? LINK_FOLLOW :
 298                                    follow);
 299         if (!ent)
 300             goto cleanup;
 301         root = ent->ino;
 302     }
 303 cleanup:
 304     g_free (pathref);
 305     return NULL;
 306 }
 307
 308 static void
 309 split_dir_name (struct vfs_class *me, char *path, char **dir, char **name, char **save)
 310 {
 311     char *s;
 312
 313     (void) me;
 314
 315     s = strrchr (path, PATH_SEP);
 316     if (s == NULL) {
 317         *save = NULL;
 318         *name = path;
 319         *dir = path + strlen(path); /* an empty string */
 320     } else {
 321         *save = s;
 322         *dir = path;
 323         *s++ = '\0';
 324         *name = s;
 325     }
 326 }
 327
 328 static struct vfs_s_entry *
 329 vfs_s_find_entry_linear (struct vfs_class *me, struct vfs_s_inode *root,
 330                          const char *a_path, int follow, int flags)
 331 {
 332     struct vfs_s_entry *ent = NULL;
 333     char * const path = g_strdup (a_path);
 334     struct vfs_s_entry *retval = NULL;
 335
 336     if (root->super->root != root)
 337         vfs_die ("We have to use _real_ root. Always. Sorry.");
 338
 339     canonicalize_pathname (path);
 340
 341     if (!(flags & FL_DIR)) {
 342         char *dirname, *name, *save;
 343         struct vfs_s_inode *ino;
 344         split_dir_name (me, path, &dirname, &name, &save);
 345         ino =
 346             vfs_s_find_inode (me, root->super, dirname, follow,
 347                               flags | FL_DIR);
 348         if (save)
 349             *save = PATH_SEP;
 350         retval = vfs_s_find_entry_tree (me, ino, name, follow, flags);
 351         g_free (path);
 352         return retval;
 353     }
 354
 355     for (ent = root->subdir; ent != NULL; ent = ent->next)
 356         if (!strcmp (ent->name, path))
 357             break;
 358
 359     if (ent && (!(MEDATA->dir_uptodate) (me, ent->ino))) {
 360 #if 1
 361         print_vfs_message (_("Directory cache expired for %s"), path);
 362 #endif
 363         vfs_s_free_entry (me, ent);
 364         ent = NULL;
 365     }
 366
 367     if (!ent) {
 368         struct vfs_s_inode *ino;
 369
 370         ino =
 371             vfs_s_new_inode (me, root->super,
 372                              vfs_s_default_stat (me, S_IFDIR | 0755));
 373         ent = vfs_s_new_entry (me, path, ino);
 374         if ((MEDATA->dir_load) (me, ino, path) == -1) {
 375             vfs_s_free_entry (me, ent);
 376             g_free (path);
 377             return NULL;
 378         }
 379         vfs_s_insert_entry (me, root, ent);
 380
 381         for (ent = root->subdir; ent != NULL; ent = ent->next)
 382             if (!strcmp (ent->name, path))
 383                 break;
 384     }
 385     if (!ent)
 386         vfs_die ("find_linear: success but directory is not there\n");
 387
 388 #if 0
 389     if (!vfs_s_resolve_symlink (me, ent, follow)) {
 390         g_free (path);
 391         return NULL;
 392     }
 393 #endif
 394     g_free (path);
 395     return ent;
 396 }
 397
 398 struct vfs_s_inode *
 399 vfs_s_find_inode (struct vfs_class *me, const struct vfs_s_super *super,
 400                   const char *path, int follow, int flags)
 401 {
 402     struct vfs_s_entry *ent;
 403     if (!(MEDATA->flags & VFS_S_REMOTE) && (!*path))
 404         return super->root;
 405     ent = (MEDATA->find_entry) (me, super->root, path, follow, flags);
 406     if (!ent)
 407         return NULL;
 408     return ent->ino;
 409 }
 410
 411 /* Ook, these were functions around directory entries / inodes */
 412 /* -------------------------------- superblock games -------------------------- */
 413
 414 static struct vfs_s_super *
 415 vfs_s_new_super (struct vfs_class *me)
 416 {
 417     struct vfs_s_super *super;
 418
 419     super = g_new0 (struct vfs_s_super, 1);
 420     super->me = me;
 421     return super;
 422 }
 423
 424 static void
 425 vfs_s_insert_super (struct vfs_class *me, struct vfs_s_super *super)
 426 {
 427     super->next = MEDATA->supers;
 428     super->prevp = &MEDATA->supers;
 429
 430     if (MEDATA->supers != NULL)
 431             MEDATA->supers->prevp = &super->next;
 432     MEDATA->supers = super;
 433 }
 434
 435 static void
 436 vfs_s_free_super (struct vfs_class *me, struct vfs_s_super *super)
 437 {
 438     if (super->root){
 439         vfs_s_free_inode (me, super->root);
 440         super->root = NULL;
 441     }
 442
 443 #if 0
 444     /* FIXME: We currently leak small ammount of memory, sometimes. Fix it if you can. */
 445     if (super->ino_usage)
 446         message (D_ERROR, " Direntry warning ",
 447                          "Super ino_usage is %d, memory leak",
 448                          super->ino_usage);
 449
 450     if (super->want_stale)
 451         message (D_ERROR, " Direntry warning ", "Super has want_stale set");
 452 #endif
 453
 454     if (super->prevp){
 455         *super->prevp = super->next;
 456         if (super->next)
 457                 super->next->prevp = super->prevp;
 458     }
 459
 460     CALL (free_archive) (me, super);
 461     g_free (super->name);
 462     g_free(super);
 463 }
 464
 465
 466 /*
 467  * Dissect the path and create corresponding superblock.  Note that inname
 468  * can be changed and the result may point inside the original string.
 469  */
 470 const char *
 471 vfs_s_get_path_mangle (struct vfs_class *me, char *inname,
 472                        struct vfs_s_super **archive, int flags)
 473 {
 474     const char *retval;
 475     char *local, *op;
 476     const char *archive_name;
 477     int result = -1;
 478     struct vfs_s_super *super;
 479     void *cookie = NULL;
 480
 481     archive_name = inname;
 482     vfs_split (inname, &local, &op);
 483     retval = (local) ? local : "";
 484
 485     if (MEDATA->archive_check)
 486         if (!(cookie = MEDATA->archive_check (me, archive_name, op)))
 487             return NULL;
 488
 489     for (super = MEDATA->supers; super != NULL; super = super->next) {
 490         /* 0 == other, 1 == same, return it, 2 == other but stop scanning */
 491         int i;
 492         if ((i =
 493              MEDATA->archive_same (me, super, archive_name, op, cookie))) {
 494             if (i == 1)
 495                 goto return_success;
 496             else
 497                 break;
 498         }
 499     }
 500
 501     if (flags & FL_NO_OPEN)
 502         ERRNOR (EIO, NULL);
 503
 504     super = vfs_s_new_super (me);
 505     result = MEDATA->open_archive (me, super, archive_name, op);
 506     if (result == -1) {
 507         vfs_s_free_super (me, super);
 508         ERRNOR (EIO, NULL);
 509     }
 510     if (!super->name)
 511         vfs_die ("You have to fill name\n");
 512     if (!super->root)
 513         vfs_die ("You have to fill root inode\n");
 514
 515     vfs_s_insert_super (me, super);
 516     vfs_stamp_create (me, super);
 517
 518   return_success:
 519     *archive = super;
 520     return retval;
 521 }
 522
 523
 524 /*
 525  * Dissect the path and create corresponding superblock.
 526  * The result should be freed.
 527  */
 528 static char *
 529 vfs_s_get_path (struct vfs_class *me, const char *inname,
 530                 struct vfs_s_super **archive, int flags)
 531 {
 532     char *buf, *retval;
 533
 534     buf = g_strdup (inname);
 535     retval = g_strdup (vfs_s_get_path_mangle (me, buf, archive, flags));
 536     g_free (buf);
 537     return retval;
 538 }
 539
 540 void
 541 vfs_s_invalidate (struct vfs_class *me, struct vfs_s_super *super)
 542 {
 543     if (!super->want_stale){
 544         vfs_s_free_inode (me, super->root);
 545         super->root = vfs_s_new_inode (me, super, vfs_s_default_stat (me, S_IFDIR | 0755));
 546     }
 547 }
 548
 549 char *
 550 vfs_s_fullpath (struct vfs_class *me, struct vfs_s_inode *ino)
 551 {
 552     if (!ino->ent)
 553         ERRNOR (EAGAIN, NULL);
 554
 555     if (!(MEDATA->flags & VFS_S_REMOTE)) {
 556         /* archives */
 557         char *newpath;
 558         char *path = g_strdup (ino->ent->name);
 559         while (1) {
 560             ino = ino->ent->dir;
 561             if (ino == ino->super->root)
 562                 break;
 563             newpath = g_strconcat (ino->ent->name, "/", path, (char *) NULL);
 564             g_free (path);
 565             path = newpath;
 566         }
 567         return path;
 568     }
 569
 570     /* remote systems */
 571     if ((!ino->ent->dir) || (!ino->ent->dir->ent))
 572         return g_strdup (ino->ent->name);
 573
 574     return g_strconcat (ino->ent->dir->ent->name, PATH_SEP_STR,
 575                         ino->ent->name, (char *) NULL);
 576 }
 577
 578 /* Support of archives */
 579 /* ------------------------ readdir & friends ----------------------------- */
 580
 581 static struct vfs_s_inode *
 582 vfs_s_inode_from_path (struct vfs_class *me, const char *name, int flags)
 583 {
 584     struct vfs_s_super *super;
 585     struct vfs_s_inode *ino;
 586     char *q;
 587
 588     if (!(q = vfs_s_get_path (me, name, &super, 0)))
 589         return NULL;
 590
 591     ino =
 592         vfs_s_find_inode (me, super, q,
 593                           flags & FL_FOLLOW ? LINK_FOLLOW : LINK_NO_FOLLOW,
 594                           flags & ~FL_FOLLOW);
 595     if ((!ino) && (!*q))
 596         /* We are asking about / directory of ftp server: assume it exists */
 597         ino =
 598             vfs_s_find_inode (me, super, q,
 599                               flags & FL_FOLLOW ? LINK_FOLLOW :
 600                               LINK_NO_FOLLOW,
 601                               FL_DIR | (flags & ~FL_FOLLOW));
 602     g_free (q);
 603     return ino;
 604 }
 605
 606 struct dirhandle {
 607     struct vfs_s_entry *cur;
 608     struct vfs_s_inode *dir;
 609 };
 610
 611 static void *
 612 vfs_s_opendir (struct vfs_class *me, const char *dirname)
 613 {
 614     struct vfs_s_inode *dir;
 615     struct dirhandle *info;
 616
 617     dir = vfs_s_inode_from_path (me, dirname, FL_DIR | FL_FOLLOW);
 618     if (!dir)
 619         return NULL;
 620     if (!S_ISDIR (dir->st.st_mode))
 621         ERRNOR (ENOTDIR, NULL);
 622
 623     dir->st.st_nlink++;
 624 #if 0
 625     if (!dir->subdir)   /* This can actually happen if we allow empty directories */
 626         ERRNOR (EAGAIN, NULL);
 627 #endif
 628     info = g_new (struct dirhandle, 1);
 629     info->cur = dir->subdir;
 630     info->dir = dir;
 631
 632     return info;
 633 }
 634
 635 static void *
 636 vfs_s_readdir(void *data)
 637 {
 638     static union vfs_dirent dir;
 639     struct dirhandle *info = (struct dirhandle *) data;
 640
 641     if (!(info->cur))
 642         return NULL;
 643
 644     if (info->cur->name) {
 645         g_strlcpy (dir.dent.d_name, info->cur->name, MC_MAXPATHLEN);
 646     } else {
 647         vfs_die("Null in structure-cannot happen");
 648     }
 649
 650     compute_namelen(&dir.dent);
 651     info->cur = info->cur->next;
 652
 653     return (void *) &dir;
 654 }
 655
 656 static int
 657 vfs_s_closedir (void *data)
 658 {
 659     struct dirhandle *info = (struct dirhandle *) data;
 660     struct vfs_s_inode *dir = info->dir;
 661
 662     vfs_s_free_inode (dir->super->me, dir);
 663     g_free (data);
 664     return 0;
 665 }
 666
 667 static int
 668 vfs_s_chdir (struct vfs_class *me, const char *path)
 669 {
 670     void *data;
 671     if (!(data = vfs_s_opendir (me, path)))
 672         return -1;
 673     vfs_s_closedir (data);
 674     return 0;
 675 }
 676
 677 /* --------------------------- stat and friends ---------------------------- */
 678
 679 static int
 680 vfs_s_internal_stat (struct vfs_class *me, const char *path, struct stat *buf, int flag)
 681 {
 682     struct vfs_s_inode *ino;
 683
 684     if (!(ino = vfs_s_inode_from_path (me, path, flag)))
 685         return -1;
 686     *buf = ino->st;
 687     return 0;
 688 }
 689
 690 static int
 691 vfs_s_stat (struct vfs_class *me, const char *path, struct stat *buf)
 692 {
 693     return vfs_s_internal_stat (me, path, buf, FL_FOLLOW);
 694 }
 695
 696 static int
 697 vfs_s_lstat (struct vfs_class *me, const char *path, struct stat *buf)
 698 {
 699     return vfs_s_internal_stat (me, path, buf, FL_NONE);
 700 }
 701
 702 static int
 703 vfs_s_fstat (void *fh, struct stat *buf)
 704 {
 705     *buf = FH->ino->st;
 706     return 0;
 707 }
 708
 709 static int
 710 vfs_s_readlink (struct vfs_class *me, const char *path, char *buf, size_t size)
 711 {
 712     struct vfs_s_inode *ino;
 713     size_t len;
 714
 715     ino = vfs_s_inode_from_path (me, path, 0);
 716     if (!ino)
 717         return -1;
 718
 719     if (!S_ISLNK (ino->st.st_mode))
 720         ERRNOR (EINVAL, -1);
 721
 722     if (ino->linkname == NULL)
 723         ERRNOR (EFAULT, -1);
 724
 725     len = strlen (ino->linkname);
 726     if (size < len)
 727        len = size;
 728     /* readlink() does not append a NUL character to buf */
 729     memcpy (buf, ino->linkname, len);
 730     return len;
 731 }
 732
 733 void *
 734 vfs_s_open (struct vfs_class *me, const char *file, int flags, int mode)
 735 {
 736     int was_changed = 0;
 737     struct vfs_s_fh *fh;
 738     struct vfs_s_super *super;
 739     char *q;
 740     struct vfs_s_inode *ino;
 741
 742     if ((q = vfs_s_get_path (me, file, &super, 0)) == NULL)
 743         return NULL;
 744     ino = vfs_s_find_inode (me, super, q, LINK_FOLLOW, FL_NONE);
 745     if (ino && ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) {
 746         g_free (q);
 747         ERRNOR (EEXIST, NULL);
 748     }
 749     if (!ino) {
 750         char *dirname, *name, *save;
 751         struct vfs_s_entry *ent;
 752         struct vfs_s_inode *dir;
 753         int tmp_handle;
 754
 755         /* If the filesystem is read-only, disable file creation */
 756         if (!(flags & O_CREAT) || !(me->write)) {
 757             g_free (q);
 758             return NULL;
 759         }
 760
 761         split_dir_name (me, q, &dirname, &name, &save);
 762         /* FIXME: check if vfs_s_find_inode returns NULL */
 763         dir = vfs_s_find_inode (me, super, dirname, LINK_FOLLOW, FL_DIR);
 764         if (save)
 765             *save = PATH_SEP;
 766         ent = vfs_s_generate_entry (me, name, dir, 0755);
 767         ino = ent->ino;
 768         vfs_s_insert_entry (me, dir, ent);
 769         tmp_handle = vfs_mkstemps (&ino->localname, me->name, name);
 770         if (tmp_handle == -1) {
 771             g_free (q);
 772             return NULL;
 773         }
 774         close (tmp_handle);
 775         was_changed = 1;
 776     }
 777
 778     g_free (q);
 779
 780     if (S_ISDIR (ino->st.st_mode))
 781         ERRNOR (EISDIR, NULL);
 782
 783     fh = g_new (struct vfs_s_fh, 1);
 784     fh->pos = 0;
 785     fh->ino = ino;
 786     fh->handle = -1;
 787     fh->changed = was_changed;
 788     fh->linear = 0;
 789
 790     if (IS_LINEAR (flags)) {
 791         if (MEDATA->linear_start) {
 792             print_vfs_message (_("Starting linear transfer..."));
 793             fh->linear = LS_LINEAR_PREOPEN;
 794         }
 795     } else if ((MEDATA->fh_open)
 796                && (MEDATA->fh_open (me, fh, flags, mode))) {
 797         g_free (fh);
 798         return NULL;
 799     }
 800
 801     if (fh->ino->localname) {
 802         fh->handle = open (fh->ino->localname, NO_LINEAR (flags), mode);
 803         if (fh->handle == -1) {
 804             g_free (fh);
 805             ERRNOR (errno, NULL);
 806         }
 807     }
 808
 809     /* i.e. we had no open files and now we have one */
 810     vfs_rmstamp (me, (vfsid) super);
 811     super->fd_usage++;
 812     fh->ino->st.st_nlink++;
 813     return fh;
 814 }
 815
 816 static ssize_t
 817 vfs_s_read (void *fh, char *buffer, int count)
 818 {
 819     int n;
 820     struct vfs_class *me = FH_SUPER->me;
 821
 822     if (FH->linear == LS_LINEAR_PREOPEN) {
 823         if (!MEDATA->linear_start (me, FH, FH->pos))
 824             return -1;
 825     }
 826
 827     if (FH->linear == LS_LINEAR_CLOSED)
 828         vfs_die ("linear_start() did not set linear_state!");
 829
 830     if (FH->linear == LS_LINEAR_OPEN)
 831         return MEDATA->linear_read (me, FH, buffer, count);
 832
 833     if (FH->handle != -1){
 834         n = read (FH->handle, buffer, count);
 835         if (n < 0)
 836             me->verrno = errno;
 837         return n;
 838     }
 839     vfs_die ("vfs_s_read: This should not happen\n");
 840     return -1;
 841 }
 842
 843 static ssize_t
 844 vfs_s_write (void *fh, const char *buffer, int count)
 845 {
 846     int n;
 847     struct vfs_class *me = FH_SUPER->me;
 848
 849     if (FH->linear)
 850         vfs_die ("no writing to linear files, please");
 851
 852     FH->changed = 1;
 853     if (FH->handle != -1){
 854         n = write (FH->handle, buffer, count);
 855         if (n < 0)
 856             me->verrno = errno;
 857         return n;
 858     }
 859     vfs_die ("vfs_s_write: This should not happen\n");
 860     return 0;
 861 }
 862
 863 static off_t
 864 vfs_s_lseek (void *fh, off_t offset, int whence)
 865 {
 866     off_t size = FH->ino->st.st_size;
 867
 868     if (FH->linear == LS_LINEAR_OPEN)
 869         vfs_die ("cannot lseek() after linear_read!");
 870
 871     if (FH->handle != -1){      /* If we have local file opened, we want to work with it */
 872         int retval = lseek (FH->handle, offset, whence);
 873         if (retval == -1)
 874             FH->ino->super->me->verrno = errno;
 875         return retval;
 876     }
 877
 878     switch (whence){
 879         case SEEK_CUR:
 880             offset += FH->pos; break;
 881         case SEEK_END:
 882             offset += size; break;
 883     }
 884     if (offset < 0)
 885         FH->pos = 0;
 886     else if (offset < size)
 887         FH->pos = offset;
 888     else
 889         FH->pos = size;
 890     return FH->pos;
 891 }
 892
 893 static int
 894 vfs_s_close (void *fh)
 895 {
 896     int res = 0;
 897     struct vfs_class *me = FH_SUPER->me;
 898
 899     FH_SUPER->fd_usage--;
 900     if (!FH_SUPER->fd_usage)
 901         vfs_stamp_create (me, FH_SUPER);
 902
 903     if (FH->linear == LS_LINEAR_OPEN)
 904         MEDATA->linear_close (me, fh);
 905     if (MEDATA->fh_close)
 906         res = MEDATA->fh_close (me, fh);
 907     if (FH->changed && MEDATA->file_store){
 908         char *s = vfs_s_fullpath (me, FH->ino);
 909         if (!s)
 910             res = -1;
 911         else {
 912             res = MEDATA->file_store (me, fh, s, FH->ino->localname);
 913             g_free (s);
 914         }
 915         vfs_s_invalidate (me, FH_SUPER);
 916     }
 917     if (FH->handle != -1)
 918         close (FH->handle);
 919
 920     vfs_s_free_inode (me, FH->ino);
 921     g_free (fh);
 922     return res;
 923 }
 924
 925 static void
 926 vfs_s_print_stats (const char *fs_name, const char *action,
 927                    const char *file_name, off_t have, off_t need)
 928 {
 929     static const char *i18n_percent_transf_format = NULL;
 930     static const char *i18n_transf_format = NULL;
 931
 932     if (i18n_percent_transf_format == NULL) {
 933         i18n_percent_transf_format =
 934             _("%s: %s: %s %3d%% (%lu bytes transferred)");
 935         i18n_transf_format = _("%s: %s: %s %lu bytes transferred");
 936     }
 937
 938     if (need)
 939         print_vfs_message (i18n_percent_transf_format, fs_name, action,
 940                            file_name, (int) ((double) have * 100 / need),
 941                            (unsigned long) have);
 942     else
 943         print_vfs_message (i18n_transf_format, fs_name, action, file_name,
 944                            (unsigned long) have);
 945 }
 946
 947 int
 948 vfs_s_retrieve_file (struct vfs_class *me, struct vfs_s_inode *ino)
 949 {
 950     /* If you want reget, you'll have to open file with O_LINEAR */
 951     off_t total = 0;
 952     char buffer[8192];
 953     int handle, n;
 954     off_t stat_size = ino->st.st_size;
 955     struct vfs_s_fh fh;
 956
 957     memset (&fh, 0, sizeof (fh));
 958
 959     fh.ino = ino;
 960     fh.handle = -1;
 961
 962     handle = vfs_mkstemps (&ino->localname, me->name, ino->ent->name);
 963     if (handle == -1) {
 964         me->verrno = errno;
 965         goto error_4;
 966     }
 967
 968     if (!MEDATA->linear_start (me, &fh, 0))
 969         goto error_3;
 970
 971     /* Clear the interrupt status */
 972     tty_got_interrupt ();
 973     tty_enable_interrupt_key ();
 974
 975     while ((n = MEDATA->linear_read (me, &fh, buffer, sizeof (buffer)))) {
 976         int t;
 977         if (n < 0)
 978             goto error_1;
 979
 980         total += n;
 981         vfs_s_print_stats (me->name, _("Getting file"), ino->ent->name,
 982                            total, stat_size);
 983
 984         if (tty_got_interrupt ())
 985             goto error_1;
 986
 987         t = write (handle, buffer, n);
 988         if (t != n) {
 989             if (t == -1)
 990                 me->verrno = errno;
 991             goto error_1;
 992         }
 993     }
 994     MEDATA->linear_close (me, &fh);
 995     close (handle);
 996
 997     tty_disable_interrupt_key ();
 998     return 0;
 999
1000   error_1:
1001     MEDATA->linear_close (me, &fh);
1002   error_3:
1003     tty_disable_interrupt_key ();
1004     close (handle);
1005     unlink (ino->localname);
1006   error_4:
1007     g_free (ino->localname);
1008     ino->localname = NULL;
1009     return -1;
1010 }
1011
1012 /* ------------------------------- mc support ---------------------------- */
1013
1014 static void
1015 vfs_s_fill_names (struct vfs_class *me, fill_names_f func)
1016 {
1017     struct vfs_s_super *a = MEDATA->supers;
1018     char *name;
1019
1020     while (a){
1021         name = g_strconcat ( a->name, "#", me->prefix, "/", /* a->current_dir->name, */ NULL);
1022         (*func)(name);
1023         g_free (name);
1024         a = a->next;
1025     }
1026 }
1027
1028 static int
1029 vfs_s_ferrno (struct vfs_class *me)
1030 {
1031     return me->verrno;
1032 }
1033
1034 /*
1035  * Get local copy of the given file.  We reuse the existing file cache
1036  * for remote filesystems.  Archives use standard VFS facilities.
1037  */
1038 static char *
1039 vfs_s_getlocalcopy (struct vfs_class *me, const char *path)
1040 {
1041     struct vfs_s_fh *fh;
1042     char *local;
1043
1044     fh = vfs_s_open (me, path, O_RDONLY, 0);
1045     if (!fh || !fh->ino || !fh->ino->localname)
1046         return NULL;
1047
1048     local = g_strdup (fh->ino->localname);
1049     vfs_s_close (fh);
1050     return local;
1051 }
1052
1053 /*
1054  * Return the local copy.  Since we are using our cache, we do nothing -
1055  * the cache will be removed when the archive is closed.
1056  */
1057 static int
1058 vfs_s_ungetlocalcopy (struct vfs_class *me, const char *path,
1059                       const char *local, int has_changed)
1060 {
1061     (void) me;
1062     (void) path;
1063     (void) local;
1064     (void) has_changed;
1065     return 0;
1066 }
1067
1068 static int
1069 vfs_s_setctl (struct vfs_class *me, const char *path, int ctlop, void *arg)
1070 {
1071     switch (ctlop) {
1072     case VFS_SETCTL_STALE_DATA:
1073         {
1074             struct vfs_s_inode *ino = vfs_s_inode_from_path (me, path, 0);
1075
1076             if (!ino)
1077                 return 0;
1078             if (arg)
1079                 ino->super->want_stale = 1;
1080             else {
1081                 ino->super->want_stale = 0;
1082                 vfs_s_invalidate (me, ino->super);
1083             }
1084             return 1;
1085         }
1086     case VFS_SETCTL_LOGFILE:
1087         MEDATA->logfile = fopen ((char *) arg, "w");
1088         return 1;
1089     case VFS_SETCTL_FLUSH:
1090         MEDATA->flush = 1;
1091         return 1;
1092     }
1093     return 0;
1094 }
1095
1096
1097 /* ----------------------------- Stamping support -------------------------- */
1098
1099 static vfsid
1100 vfs_s_getid (struct vfs_class *me, const char *path)
1101 {
1102     struct vfs_s_super *archive;
1103     char *p;
1104
1105     if (!(p = vfs_s_get_path (me, path, &archive, FL_NO_OPEN)))
1106         return NULL;
1107     g_free(p);
1108     return (vfsid) archive;
1109 }
1110
1111 static int
1112 vfs_s_nothingisopen (vfsid id)
1113 {
1114     (void) id;
1115     /* Our data structures should survive free of superblock at any time */
1116     return 1;
1117 }
1118
1119 static void
1120 vfs_s_free (vfsid id)
1121 {
1122     vfs_s_free_super (((struct vfs_s_super *)id)->me, (struct vfs_s_super *)id);
1123 }
1124
1125 static int
1126 vfs_s_dir_uptodate (struct vfs_class *me, struct vfs_s_inode *ino)
1127 {
1128     struct timeval tim;
1129
1130     if (MEDATA->flush) {
1131         MEDATA->flush = 0;
1132         return 0;
1133     }
1134
1135     gettimeofday(&tim, NULL);
1136     if (tim.tv_sec < ino->timestamp.tv_sec)
1137         return 1;
1138     return 0;
1139 }
1140
1141 /* Initialize one of our subclasses - fill common functions */
1142 void
1143 vfs_s_init_class (struct vfs_class *vclass, struct vfs_s_subclass *sub)
1144 {
1145     vclass->data = sub;
1146     vclass->fill_names = vfs_s_fill_names;
1147     vclass->open = vfs_s_open;
1148     vclass->close = vfs_s_close;
1149     vclass->read = vfs_s_read;
1150     if (!(sub->flags & VFS_S_READONLY)) {
1151         vclass->write = vfs_s_write;
1152     }
1153     vclass->opendir = vfs_s_opendir;
1154     vclass->readdir = vfs_s_readdir;
1155     vclass->closedir = vfs_s_closedir;
1156     vclass->stat = vfs_s_stat;
1157     vclass->lstat = vfs_s_lstat;
1158     vclass->fstat = vfs_s_fstat;
1159     vclass->readlink = vfs_s_readlink;
1160     vclass->chdir = vfs_s_chdir;
1161     vclass->ferrno = vfs_s_ferrno;
1162     vclass->lseek = vfs_s_lseek;
1163     vclass->getid = vfs_s_getid;
1164     vclass->nothingisopen = vfs_s_nothingisopen;
1165     vclass->free = vfs_s_free;
1166     if (sub->flags & VFS_S_REMOTE) {
1167         vclass->getlocalcopy = vfs_s_getlocalcopy;
1168         vclass->ungetlocalcopy = vfs_s_ungetlocalcopy;
1169         sub->find_entry = vfs_s_find_entry_linear;
1170     } else {
1171         sub->find_entry = vfs_s_find_entry_tree;
1172     }
1173     vclass->setctl = vfs_s_setctl;
1174     sub->dir_uptodate = vfs_s_dir_uptodate;
1175 }
1176
1177 /* ----------- Utility functions for networked filesystems  -------------- */
1178
1179 #ifdef USE_NETCODE
1180 int
1181 vfs_s_select_on_two (int fd1, int fd2)
1182 {
1183     fd_set set;
1184     struct timeval timeout;
1185     int v;
1186     int maxfd = (fd1 > fd2 ? fd1 : fd2) + 1;
1187
1188     timeout.tv_sec  = 1;
1189     timeout.tv_usec = 0;
1190     FD_ZERO (&set);
1191     FD_SET (fd1, &set);
1192     FD_SET (fd2, &set);
1193     v = select (maxfd, &set, 0, 0, &timeout);
1194     if (v <= 0)
1195         return v;
1196     if (FD_ISSET (fd1, &set))
1197         return 1;
1198     if (FD_ISSET (fd2, &set))
1199         return 2;
1200     return -1;
1201 }
1202
1203 int
1204 vfs_s_get_line (struct vfs_class *me, int sock, char *buf, int buf_len, char term)
1205 {
1206     FILE *logfile = MEDATA->logfile;
1207     int i;
1208     char c;
1209
1210     for (i = 0; i < buf_len - 1; i++, buf++){
1211         if (read (sock, buf, sizeof(char)) <= 0)
1212             return 0;
1213         if (logfile){
1214             fwrite (buf, 1, 1, logfile);
1215             fflush (logfile);
1216         }
1217         if (*buf == term){
1218             *buf = 0;
1219             return 1;
1220         }
1221     }
1222
1223     /* Line is too long - terminate buffer and discard the rest of line */
1224     *buf = 0;
1225     while (read (sock, &c, sizeof (c)) > 0) {
1226         if (logfile){
1227             fwrite (&c, 1, 1, logfile);
1228             fflush (logfile);
1229         }
1230         if (c == '\n')
1231             return 1;
1232     }
1233     return 0;
1234 }
1235
1236 int
1237 vfs_s_get_line_interruptible (struct vfs_class *me, char *buffer, int size, int fd)
1238 {
1239     int n;
1240     int i;
1241
1242     (void) me;
1243
1244     tty_enable_interrupt_key ();
1245     for (i = 0; i < size-1; i++){
1246         n = read (fd, buffer+i, 1);
1247         tty_disable_interrupt_key ();
1248         if (n == -1 && errno == EINTR){
1249             buffer [i] = 0;
1250             return EINTR;
1251         }
1252         if (n == 0){
1253             buffer [i] = 0;
1254             return 0;
1255         }
1256         if (buffer [i] == '\n'){
1257             buffer [i] = 0;
1258             return 1;
1259         }
1260     }
1261     buffer [size-1] = 0;
1262     return 0;
1263 }
1264 #endif /* USE_NETCODE */