source/smbd/vfs.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    VFS initialisation and support functions
   5    Copyright (C) Tim Potter 1999
   6    Copyright (C) Alexander Bokovoy 2002
   7    Copyright (C) James Peach 2006
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21
  22    This work was sponsored by Optifacio Software Services, Inc.
  23 */
  24
  25 #include "includes.h"
  26
  27 #undef DBGC_CLASS
  28 #define DBGC_CLASS DBGC_VFS
  29
  30 static_decl_vfs;
  31
  32 struct vfs_init_function_entry {
  33         char *name;
  34         const vfs_op_tuple *vfs_op_tuples;
  35         struct vfs_init_function_entry *prev, *next;
  36 };
  37
  38 static struct vfs_init_function_entry *backends = NULL;
  39
  40 /****************************************************************************
  41     maintain the list of available backends
  42 ****************************************************************************/
  43
  44 static struct vfs_init_function_entry *vfs_find_backend_entry(const char *name)
  45 {
  46         struct vfs_init_function_entry *entry = backends;
  47
  48         DEBUG(10, ("vfs_find_backend_entry called for %s\n", name));
  49
  50         while(entry) {
  51                 if (strcmp(entry->name, name)==0) return entry;
  52                 entry = entry->next;
  53         }
  54
  55         return NULL;
  56 }
  57
  58 NTSTATUS smb_register_vfs(int version, const char *name, const vfs_op_tuple *vfs_op_tuples)
  59 {
  60         struct vfs_init_function_entry *entry = backends;
  61
  62         if ((version != SMB_VFS_INTERFACE_VERSION)) {
  63                 DEBUG(0, ("Failed to register vfs module.\n"
  64                           "The module was compiled against SMB_VFS_INTERFACE_VERSION %d,\n"
  65                           "current SMB_VFS_INTERFACE_VERSION is %d.\n"
  66                           "Please recompile against the current Samba Version!\n",
  67                           version, SMB_VFS_INTERFACE_VERSION));
  68                 return NT_STATUS_OBJECT_TYPE_MISMATCH;
  69         }
  70
  71         if (!name || !name[0] || !vfs_op_tuples) {
  72                 DEBUG(0,("smb_register_vfs() called with NULL pointer or empty name!\n"));
  73                 return NT_STATUS_INVALID_PARAMETER;
  74         }
  75
  76         if (vfs_find_backend_entry(name)) {
  77                 DEBUG(0,("VFS module %s already loaded!\n", name));
  78                 return NT_STATUS_OBJECT_NAME_COLLISION;
  79         }
  80
  81         entry = SMB_XMALLOC_P(struct vfs_init_function_entry);
  82         entry->name = smb_xstrdup(name);
  83         entry->vfs_op_tuples = vfs_op_tuples;
  84
  85         DLIST_ADD(backends, entry);
  86         DEBUG(5, ("Successfully added vfs backend '%s'\n", name));
  87         return NT_STATUS_OK;
  88 }
  89
  90 /****************************************************************************
  91   initialise default vfs hooks
  92 ****************************************************************************/
  93
  94 static void vfs_init_default(connection_struct *conn)
  95 {
  96         DEBUG(3, ("Initialising default vfs hooks\n"));
  97         vfs_init_custom(conn, DEFAULT_VFS_MODULE_NAME);
  98 }
  99
 100 /****************************************************************************
 101   initialise custom vfs hooks
 102  ****************************************************************************/
 103
 104 static inline void vfs_set_operation(struct vfs_ops * vfs, vfs_op_type which,
 105                                 struct vfs_handle_struct * handle, void * op)
 106 {
 107         ((struct vfs_handle_struct **)&vfs->handles)[which] = handle;
 108         ((void **)(void *)&vfs->ops)[which] = op;
 109 }
 110
 111 bool vfs_init_custom(connection_struct *conn, const char *vfs_object)
 112 {
 113         const vfs_op_tuple *ops;
 114         char *module_path = NULL;
 115         char *module_name = NULL;
 116         char *module_param = NULL, *p;
 117         int i;
 118         vfs_handle_struct *handle;
 119         const struct vfs_init_function_entry *entry;
 120
 121         if (!conn||!vfs_object||!vfs_object[0]) {
 122                 DEBUG(0,("vfs_init_custon() called with NULL pointer or emtpy vfs_object!\n"));
 123                 return False;
 124         }
 125
 126         if(!backends) {
 127                 static_init_vfs;
 128         }
 129
 130         DEBUG(3, ("Initialising custom vfs hooks from [%s]\n", vfs_object));
 131
 132         module_path = smb_xstrdup(vfs_object);
 133
 134         p = strchr_m(module_path, ':');
 135
 136         if (p) {
 137                 *p = 0;
 138                 module_param = p+1;
 139                 trim_char(module_param, ' ', ' ');
 140         }
 141
 142         trim_char(module_path, ' ', ' ');
 143
 144         module_name = smb_xstrdup(module_path);
 145
 146         if ((module_name[0] == '/') &&
 147             (strcmp(module_path, DEFAULT_VFS_MODULE_NAME) != 0)) {
 148
 149                 /*
 150                  * Extract the module name from the path. Just use the base
 151                  * name of the last path component.
 152                  */
 153
 154                 SAFE_FREE(module_name);
 155                 module_name = smb_xstrdup(strrchr_m(module_path, '/')+1);
 156
 157                 p = strchr_m(module_name, '.');
 158
 159                 if (p != NULL) {
 160                         *p = '\0';
 161                 }
 162         }
 163
 164         /* First, try to load the module with the new module system */
 165         if((entry = vfs_find_backend_entry(module_name)) ||
 166            (NT_STATUS_IS_OK(smb_probe_module("vfs", module_path)) &&
 167                 (entry = vfs_find_backend_entry(module_name)))) {
 168
 169                 DEBUGADD(5,("Successfully loaded vfs module [%s] with the new modules system\n", vfs_object));
 170
 171                 if ((ops = entry->vfs_op_tuples) == NULL) {
 172                         DEBUG(0, ("entry->vfs_op_tuples==NULL for [%s] failed\n", vfs_object));
 173                         goto fail;
 174                 }
 175         } else {
 176                 DEBUG(0,("Can't find a vfs module [%s]\n",vfs_object));
 177                 goto fail;
 178         }
 179
 180         handle = TALLOC_ZERO_P(conn->mem_ctx,vfs_handle_struct);
 181         if (!handle) {
 182                 DEBUG(0,("TALLOC_ZERO() failed!\n"));
 183                 goto fail;
 184         }
 185         memcpy(&handle->vfs_next, &conn->vfs, sizeof(struct vfs_ops));
 186         handle->conn = conn;
 187         if (module_param) {
 188                 handle->param = talloc_strdup(conn->mem_ctx, module_param);
 189         }
 190         DLIST_ADD(conn->vfs_handles, handle);
 191
 192         for(i=0; ops[i].op != NULL; i++) {
 193                 DEBUG(5, ("Checking operation #%d (type %d, layer %d)\n", i, ops[i].type, ops[i].layer));
 194                 if(ops[i].layer == SMB_VFS_LAYER_OPAQUE) {
 195                         /* If this operation was already made opaque by different module, it
 196                          * will be overridden here.
 197                          */
 198                         DEBUGADD(5, ("Making operation type %d opaque [module %s]\n", ops[i].type, vfs_object));
 199                         vfs_set_operation(&conn->vfs_opaque, ops[i].type, handle, ops[i].op);
 200                 }
 201                 /* Change current VFS disposition*/
 202                 DEBUGADD(5, ("Accepting operation type %d from module %s\n", ops[i].type, vfs_object));
 203                 vfs_set_operation(&conn->vfs, ops[i].type, handle, ops[i].op);
 204         }
 205
 206         SAFE_FREE(module_path);
 207         SAFE_FREE(module_name);
 208         return True;
 209
 210  fail:
 211         SAFE_FREE(module_path);
 212         SAFE_FREE(module_name);
 213         return False;
 214 }
 215
 216 /*****************************************************************
 217  Allow VFS modules to extend files_struct with VFS-specific state.
 218  This will be ok for small numbers of extensions, but might need to
 219  be refactored if it becomes more widely used.
 220 ******************************************************************/
 221
 222 #define EXT_DATA_AREA(e) ((uint8 *)(e) + sizeof(struct vfs_fsp_data))
 223
 224 void *vfs_add_fsp_extension_notype(vfs_handle_struct *handle, files_struct *fsp, size_t ext_size)
 225 {
 226         struct vfs_fsp_data *ext;
 227         void * ext_data;
 228
 229         /* Prevent VFS modules adding multiple extensions. */
 230         if ((ext_data = vfs_fetch_fsp_extension(handle, fsp))) {
 231                 return ext_data;
 232         }
 233
 234         ext = (struct vfs_fsp_data *)TALLOC_ZERO(
 235                 handle->conn->mem_ctx, sizeof(struct vfs_fsp_data) + ext_size);
 236         if (ext == NULL) {
 237                 return NULL;
 238         }
 239
 240         ext->owner = handle;
 241         ext->next = fsp->vfs_extension;
 242         fsp->vfs_extension = ext;
 243         return EXT_DATA_AREA(ext);
 244 }
 245
 246 void vfs_remove_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
 247 {
 248         struct vfs_fsp_data *curr;
 249         struct vfs_fsp_data *prev;
 250
 251         for (curr = fsp->vfs_extension, prev = NULL;
 252              curr;
 253              prev = curr, curr = curr->next) {
 254                 if (curr->owner == handle) {
 255                     if (prev) {
 256                             prev->next = curr->next;
 257                     } else {
 258                             fsp->vfs_extension = curr->next;
 259                     }
 260                     TALLOC_FREE(curr);
 261                     return;
 262                 }
 263         }
 264 }
 265
 266 void *vfs_memctx_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
 267 {
 268         struct vfs_fsp_data *head;
 269
 270         for (head = fsp->vfs_extension; head; head = head->next) {
 271                 if (head->owner == handle) {
 272                         return head;
 273                 }
 274         }
 275
 276         return NULL;
 277 }
 278
 279 void *vfs_fetch_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
 280 {
 281         struct vfs_fsp_data *head;
 282
 283         head = (struct vfs_fsp_data *)vfs_memctx_fsp_extension(handle, fsp);
 284         if (head != NULL) {
 285                 return EXT_DATA_AREA(head);
 286         }
 287
 288         return NULL;
 289 }
 290
 291 #undef EXT_DATA_AREA
 292
 293 /*****************************************************************
 294  Generic VFS init.
 295 ******************************************************************/
 296
 297 bool smbd_vfs_init(connection_struct *conn)
 298 {
 299         const char **vfs_objects;
 300         unsigned int i = 0;
 301         int j = 0;
 302
 303         /* Normal share - initialise with disk access functions */
 304         vfs_init_default(conn);
 305         vfs_objects = lp_vfs_objects(SNUM(conn));
 306
 307         /* Override VFS functions if 'vfs object' was not specified*/
 308         if (!vfs_objects || !vfs_objects[0])
 309                 return True;
 310
 311         for (i=0; vfs_objects[i] ;) {
 312                 i++;
 313         }
 314
 315         for (j=i-1; j >= 0; j--) {
 316                 if (!vfs_init_custom(conn, vfs_objects[j])) {
 317                         DEBUG(0, ("smbd_vfs_init: vfs_init_custom failed for %s\n", vfs_objects[j]));
 318                         return False;
 319                 }
 320         }
 321         return True;
 322 }
 323
 324 /*******************************************************************
 325  Check if directory exists.
 326 ********************************************************************/
 327
 328 bool vfs_directory_exist(connection_struct *conn, const char *dname, SMB_STRUCT_STAT *st)
 329 {
 330         SMB_STRUCT_STAT st2;
 331         bool ret;
 332
 333         if (!st)
 334                 st = &st2;
 335
 336         if (SMB_VFS_STAT(conn,dname,st) != 0)
 337                 return(False);
 338
 339         ret = S_ISDIR(st->st_mode);
 340         if(!ret)
 341                 errno = ENOTDIR;
 342
 343         return ret;
 344 }
 345
 346 /*******************************************************************
 347  Check if an object exists in the vfs.
 348 ********************************************************************/
 349
 350 bool vfs_object_exist(connection_struct *conn,const char *fname,SMB_STRUCT_STAT *sbuf)
 351 {
 352         SMB_STRUCT_STAT st;
 353
 354         if (!sbuf)
 355                 sbuf = &st;
 356
 357         ZERO_STRUCTP(sbuf);
 358
 359         if (SMB_VFS_STAT(conn,fname,sbuf) == -1)
 360                 return(False);
 361         return True;
 362 }
 363
 364 /*******************************************************************
 365  Check if a file exists in the vfs.
 366 ********************************************************************/
 367
 368 bool vfs_file_exist(connection_struct *conn, const char *fname,SMB_STRUCT_STAT *sbuf)
 369 {
 370         SMB_STRUCT_STAT st;
 371
 372         if (!sbuf)
 373                 sbuf = &st;
 374
 375         ZERO_STRUCTP(sbuf);
 376
 377         if (SMB_VFS_STAT(conn,fname,sbuf) == -1)
 378                 return False;
 379         return(S_ISREG(sbuf->st_mode));
 380 }
 381
 382 /****************************************************************************
 383  Read data from fsp on the vfs. (note: EINTR re-read differs from vfs_write_data)
 384 ****************************************************************************/
 385
 386 ssize_t vfs_read_data(files_struct *fsp, char *buf, size_t byte_count)
 387 {
 388         size_t total=0;
 389
 390         while (total < byte_count)
 391         {
 392                 ssize_t ret = SMB_VFS_READ(fsp, buf + total,
 393                                            byte_count - total);
 394
 395                 if (ret == 0) return total;
 396                 if (ret == -1) {
 397                         if (errno == EINTR)
 398                                 continue;
 399                         else
 400                                 return -1;
 401                 }
 402                 total += ret;
 403         }
 404         return (ssize_t)total;
 405 }
 406
 407 ssize_t vfs_pread_data(files_struct *fsp, char *buf,
 408                 size_t byte_count, SMB_OFF_T offset)
 409 {
 410         size_t total=0;
 411
 412         while (total < byte_count)
 413         {
 414                 ssize_t ret = SMB_VFS_PREAD(fsp, buf + total,
 415                                         byte_count - total, offset + total);
 416
 417                 if (ret == 0) return total;
 418                 if (ret == -1) {
 419                         if (errno == EINTR)
 420                                 continue;
 421                         else
 422                                 return -1;
 423                 }
 424                 total += ret;
 425         }
 426         return (ssize_t)total;
 427 }
 428
 429 /****************************************************************************
 430  Write data to a fd on the vfs.
 431 ****************************************************************************/
 432
 433 ssize_t vfs_write_data(struct smb_request *req,
 434                         files_struct *fsp,
 435                         const char *buffer,
 436                         size_t N)
 437 {
 438         size_t total=0;
 439         ssize_t ret;
 440
 441         if (req && req->unread_bytes) {
 442                 SMB_ASSERT(req->unread_bytes == N);
 443                 /* VFS_RECVFILE must drain the socket
 444                  * before returning. */
 445                 req->unread_bytes = 0;
 446                 return SMB_VFS_RECVFILE(smbd_server_fd(),
 447                                         fsp,
 448                                         (SMB_OFF_T)-1,
 449                                         N);
 450         }
 451
 452         while (total < N) {
 453                 ret = SMB_VFS_WRITE(fsp, buffer + total, N - total);
 454
 455                 if (ret == -1)
 456                         return -1;
 457                 if (ret == 0)
 458                         return total;
 459
 460                 total += ret;
 461         }
 462         return (ssize_t)total;
 463 }
 464
 465 ssize_t vfs_pwrite_data(struct smb_request *req,
 466                         files_struct *fsp,
 467                         const char *buffer,
 468                         size_t N,
 469                         SMB_OFF_T offset)
 470 {
 471         size_t total=0;
 472         ssize_t ret;
 473
 474         if (req && req->unread_bytes) {
 475                 SMB_ASSERT(req->unread_bytes == N);
 476                 /* VFS_RECVFILE must drain the socket
 477                  * before returning. */
 478                 req->unread_bytes = 0;
 479                 return SMB_VFS_RECVFILE(smbd_server_fd(),
 480                                         fsp,
 481                                         offset,
 482                                         N);
 483         }
 484
 485         while (total < N) {
 486                 ret = SMB_VFS_PWRITE(fsp, buffer + total, N - total,
 487                                      offset + total);
 488
 489                 if (ret == -1)
 490                         return -1;
 491                 if (ret == 0)
 492                         return total;
 493
 494                 total += ret;
 495         }
 496         return (ssize_t)total;
 497 }
 498 /****************************************************************************
 499  An allocate file space call using the vfs interface.
 500  Allocates space for a file from a filedescriptor.
 501  Returns 0 on success, -1 on failure.
 502 ****************************************************************************/
 503
 504 int vfs_allocate_file_space(files_struct *fsp, SMB_BIG_UINT len)
 505 {
 506         int ret;
 507         SMB_STRUCT_STAT st;
 508         connection_struct *conn = fsp->conn;
 509         SMB_BIG_UINT space_avail;
 510         SMB_BIG_UINT bsize,dfree,dsize;
 511
 512         release_level_2_oplocks_on_change(fsp);
 513
 514         /*
 515          * Actually try and commit the space on disk....
 516          */
 517
 518         DEBUG(10,("vfs_allocate_file_space: file %s, len %.0f\n", fsp->fsp_name, (double)len ));
 519
 520         if (((SMB_OFF_T)len) < 0) {
 521                 DEBUG(0,("vfs_allocate_file_space: %s negative len requested.\n", fsp->fsp_name ));
 522                 errno = EINVAL;
 523                 return -1;
 524         }
 525
 526         ret = SMB_VFS_FSTAT(fsp, &st);
 527         if (ret == -1)
 528                 return ret;
 529
 530         if (len == (SMB_BIG_UINT)st.st_size)
 531                 return 0;
 532
 533         if (len < (SMB_BIG_UINT)st.st_size) {
 534                 /* Shrink - use ftruncate. */
 535
 536                 DEBUG(10,("vfs_allocate_file_space: file %s, shrink. Current size %.0f\n",
 537                                 fsp->fsp_name, (double)st.st_size ));
 538
 539                 flush_write_cache(fsp, SIZECHANGE_FLUSH);
 540                 if ((ret = SMB_VFS_FTRUNCATE(fsp, (SMB_OFF_T)len)) != -1) {
 541                         set_filelen_write_cache(fsp, len);
 542                 }
 543                 return ret;
 544         }
 545
 546         /* Grow - we need to test if we have enough space. */
 547
 548         if (!lp_strict_allocate(SNUM(fsp->conn)))
 549                 return 0;
 550
 551         len -= st.st_size;
 552         len /= 1024; /* Len is now number of 1k blocks needed. */
 553         space_avail = get_dfree_info(conn,fsp->fsp_name,False,&bsize,&dfree,&dsize);
 554         if (space_avail == (SMB_BIG_UINT)-1) {
 555                 return -1;
 556         }
 557
 558         DEBUG(10,("vfs_allocate_file_space: file %s, grow. Current size %.0f, needed blocks = %.0f, space avail = %.0f\n",
 559                         fsp->fsp_name, (double)st.st_size, (double)len, (double)space_avail ));
 560
 561         if (len > space_avail) {
 562                 errno = ENOSPC;
 563                 return -1;
 564         }
 565
 566         return 0;
 567 }
 568
 569 /****************************************************************************
 570  A vfs set_filelen call.
 571  set the length of a file from a filedescriptor.
 572  Returns 0 on success, -1 on failure.
 573 ****************************************************************************/
 574
 575 int vfs_set_filelen(files_struct *fsp, SMB_OFF_T len)
 576 {
 577         int ret;
 578
 579         release_level_2_oplocks_on_change(fsp);
 580         DEBUG(10,("vfs_set_filelen: ftruncate %s to len %.0f\n", fsp->fsp_name, (double)len));
 581         flush_write_cache(fsp, SIZECHANGE_FLUSH);
 582         if ((ret = SMB_VFS_FTRUNCATE(fsp, len)) != -1) {
 583                 set_filelen_write_cache(fsp, len);
 584                 notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
 585                              FILE_NOTIFY_CHANGE_SIZE
 586                              | FILE_NOTIFY_CHANGE_ATTRIBUTES,
 587                              fsp->fsp_name);
 588         }
 589
 590         return ret;
 591 }
 592
 593 /****************************************************************************
 594  A vfs fill sparse call.
 595  Writes zeros from the end of file to len, if len is greater than EOF.
 596  Used only by strict_sync.
 597  Returns 0 on success, -1 on failure.
 598 ****************************************************************************/
 599
 600 static char *sparse_buf;
 601 #define SPARSE_BUF_WRITE_SIZE (32*1024)
 602
 603 int vfs_fill_sparse(files_struct *fsp, SMB_OFF_T len)
 604 {
 605         int ret;
 606         SMB_STRUCT_STAT st;
 607         SMB_OFF_T offset;
 608         size_t total;
 609         size_t num_to_write;
 610         ssize_t pwrite_ret;
 611
 612         release_level_2_oplocks_on_change(fsp);
 613         ret = SMB_VFS_FSTAT(fsp, &st);
 614         if (ret == -1) {
 615                 return ret;
 616         }
 617
 618         if (len <= st.st_size) {
 619                 return 0;
 620         }
 621
 622         DEBUG(10,("vfs_fill_sparse: write zeros in file %s from len %.0f to len %.0f (%.0f bytes)\n",
 623                 fsp->fsp_name, (double)st.st_size, (double)len, (double)(len - st.st_size)));
 624
 625         flush_write_cache(fsp, SIZECHANGE_FLUSH);
 626
 627 #ifdef HAVE_POSIX_FALLOCATE
 628         set_filelen_write_cache(fsp, len);
 629 #else
 630         if (!sparse_buf) {
 631                 sparse_buf = SMB_CALLOC_ARRAY(char, SPARSE_BUF_WRITE_SIZE);
 632                 if (!sparse_buf) {
 633                         errno = ENOMEM;
 634                         return -1;
 635                 }
 636         }
 637
 638         offset = st.st_size;
 639         num_to_write = len - st.st_size;
 640         total = 0;
 641
 642         while (total < num_to_write) {
 643                 size_t curr_write_size = MIN(SPARSE_BUF_WRITE_SIZE, (num_to_write - total));
 644
 645                 pwrite_ret = SMB_VFS_PWRITE(fsp, sparse_buf, curr_write_size, offset + total);
 646                 if (pwrite_ret == -1) {
 647                         DEBUG(10,("vfs_fill_sparse: SMB_VFS_PWRITE for file %s failed with error %s\n",
 648                                 fsp->fsp_name, strerror(errno) ));
 649                         return -1;
 650                 }
 651                 if (pwrite_ret == 0) {
 652                         return 0;
 653                 }
 654
 655                 total += pwrite_ret;
 656         }
 657
 658         ret = 0;
 659 #endif
 660
 661         set_filelen_write_cache(fsp, len);
 662         return ret;
 663 }
 664
 665 /****************************************************************************
 666  Transfer some data (n bytes) between two file_struct's.
 667 ****************************************************************************/
 668
 669 static ssize_t vfs_read_fn(void *file, void *buf, size_t len)
 670 {
 671         struct files_struct *fsp = (struct files_struct *)file;
 672
 673         return SMB_VFS_READ(fsp, buf, len);
 674 }
 675
 676 static ssize_t vfs_write_fn(void *file, const void *buf, size_t len)
 677 {
 678         struct files_struct *fsp = (struct files_struct *)file;
 679
 680         return SMB_VFS_WRITE(fsp, buf, len);
 681 }
 682
 683 SMB_OFF_T vfs_transfer_file(files_struct *in, files_struct *out, SMB_OFF_T n)
 684 {
 685         return transfer_file_internal((void *)in, (void *)out, n,
 686                                       vfs_read_fn, vfs_write_fn);
 687 }
 688
 689 /*******************************************************************
 690  A vfs_readdir wrapper which just returns the file name.
 691 ********************************************************************/
 692
 693 char *vfs_readdirname(connection_struct *conn, void *p)
 694 {
 695         SMB_STRUCT_DIRENT *ptr= NULL;
 696         char *dname;
 697
 698         if (!p)
 699                 return(NULL);
 700
 701         ptr = SMB_VFS_READDIR(conn, (DIR *)p);
 702         if (!ptr)
 703                 return(NULL);
 704
 705         dname = ptr->d_name;
 706
 707 #ifdef NEXT2
 708         if (telldir(p) < 0)
 709                 return(NULL);
 710 #endif
 711
 712 #ifdef HAVE_BROKEN_READDIR_NAME
 713         /* using /usr/ucb/cc is BAD */
 714         dname = dname - 2;
 715 #endif
 716
 717         return(dname);
 718 }
 719
 720 /*******************************************************************
 721  A wrapper for vfs_chdir().
 722 ********************************************************************/
 723
 724 int vfs_ChDir(connection_struct *conn, const char *path)
 725 {
 726         int res;
 727         static char *LastDir = NULL;
 728
 729         if (!LastDir) {
 730                 LastDir = SMB_STRDUP("");
 731         }
 732
 733         if (strcsequal(path,"."))
 734                 return(0);
 735
 736         if (*path == '/' && strcsequal(LastDir,path))
 737                 return(0);
 738
 739         DEBUG(4,("vfs_ChDir to %s\n",path));
 740
 741         res = SMB_VFS_CHDIR(conn,path);
 742         if (!res) {
 743                 SAFE_FREE(LastDir);
 744                 LastDir = SMB_STRDUP(path);
 745         }
 746         return(res);
 747 }
 748
 749 /*******************************************************************
 750  Return the absolute current directory path - given a UNIX pathname.
 751  Note that this path is returned in DOS format, not UNIX
 752  format. Note this can be called with conn == NULL.
 753 ********************************************************************/
 754
 755 struct getwd_cache_key {
 756         SMB_DEV_T dev;
 757         SMB_INO_T ino;
 758 };
 759
 760 char *vfs_GetWd(TALLOC_CTX *ctx, connection_struct *conn)
 761 {
 762         char s[PATH_MAX+1];
 763         SMB_STRUCT_STAT st, st2;
 764         char *result;
 765         DATA_BLOB cache_value;
 766         struct getwd_cache_key key;
 767
 768         *s = 0;
 769
 770         if (!lp_getwd_cache()) {
 771                 goto nocache;
 772         }
 773
 774         SET_STAT_INVALID(st);
 775
 776         if (SMB_VFS_STAT(conn, ".",&st) == -1) {
 777                 /*
 778                  * Known to fail for root: the directory may be NFS-mounted
 779                  * and exported with root_squash (so has no root access).
 780                  */
 781                 DEBUG(1,("vfs_GetWd: couldn't stat \".\" error %s "
 782                          "(NFS problem ?)\n", strerror(errno) ));
 783                 goto nocache;
 784         }
 785
 786         ZERO_STRUCT(key); /* unlikely, but possible padding */
 787         key.dev = st.st_dev;
 788         key.ino = st.st_ino;
 789
 790         if (!memcache_lookup(smbd_memcache(), GETWD_CACHE,
 791                              data_blob_const(&key, sizeof(key)),
 792                              &cache_value)) {
 793                 goto nocache;
 794         }
 795
 796         SMB_ASSERT((cache_value.length > 0)
 797                    && (cache_value.data[cache_value.length-1] == '\0'));
 798
 799         if ((SMB_VFS_STAT(conn, (char *)cache_value.data, &st2) == 0)
 800             && (st.st_dev == st2.st_dev) && (st.st_ino == st2.st_ino)
 801             && (S_ISDIR(st.st_mode))) {
 802                 /*
 803                  * Ok, we're done
 804                  */
 805                 result = talloc_strdup(ctx, (char *)cache_value.data);
 806                 if (result == NULL) {
 807                         errno = ENOMEM;
 808                 }
 809                 return result;
 810         }
 811
 812  nocache:
 813
 814         /*
 815          * We don't have the information to hand so rely on traditional
 816          * methods. The very slow getcwd, which spawns a process on some
 817          * systems, or the not quite so bad getwd.
 818          */
 819
 820         if (!SMB_VFS_GETWD(conn,s)) {
 821                 DEBUG(0, ("vfs_GetWd: SMB_VFS_GETWD call failed: %s\n",
 822                           strerror(errno)));
 823                 return NULL;
 824         }
 825
 826         if (lp_getwd_cache() && VALID_STAT(st)) {
 827                 ZERO_STRUCT(key); /* unlikely, but possible padding */
 828                 key.dev = st.st_dev;
 829                 key.ino = st.st_ino;
 830
 831                 memcache_add(smbd_memcache(), GETWD_CACHE,
 832                              data_blob_const(&key, sizeof(key)),
 833                              data_blob_const(s, strlen(s)+1));
 834         }
 835
 836         result = talloc_strdup(ctx, s);
 837         if (result == NULL) {
 838                 errno = ENOMEM;
 839         }
 840         return result;
 841 }
 842
 843 /*******************************************************************
 844  Reduce a file name, removing .. elements and checking that
 845  it is below dir in the heirachy. This uses realpath.
 846 ********************************************************************/
 847
 848 NTSTATUS check_reduced_name(connection_struct *conn, const char *fname)
 849 {
 850 #ifdef REALPATH_TAKES_NULL
 851         bool free_resolved_name = True;
 852 #else
 853         char resolved_name_buf[PATH_MAX+1];
 854         bool free_resolved_name = False;
 855 #endif
 856         char *resolved_name = NULL;
 857         size_t con_path_len = strlen(conn->connectpath);
 858         char *p = NULL;
 859
 860         DEBUG(3,("reduce_name [%s] [%s]\n", fname, conn->connectpath));
 861
 862 #ifdef REALPATH_TAKES_NULL
 863         resolved_name = SMB_VFS_REALPATH(conn,fname,NULL);
 864 #else
 865         resolved_name = SMB_VFS_REALPATH(conn,fname,resolved_name_buf);
 866 #endif
 867
 868         if (!resolved_name) {
 869                 switch (errno) {
 870                         case ENOTDIR:
 871                                 DEBUG(3,("reduce_name: Component not a directory in getting realpath for %s\n", fname));
 872                                 return map_nt_error_from_unix(errno);
 873                         case ENOENT:
 874                         {
 875                                 TALLOC_CTX *ctx = talloc_tos();
 876                                 char *tmp_fname = NULL;
 877                                 char *last_component = NULL;
 878                                 /* Last component didn't exist. Remove it and try and canonicalise the directory. */
 879
 880                                 tmp_fname = talloc_strdup(ctx, fname);
 881                                 if (!tmp_fname) {
 882                                         return NT_STATUS_NO_MEMORY;
 883                                 }
 884                                 p = strrchr_m(tmp_fname, '/');
 885                                 if (p) {
 886                                         *p++ = '\0';
 887                                         last_component = p;
 888                                 } else {
 889                                         last_component = tmp_fname;
 890                                         tmp_fname = talloc_strdup(ctx,
 891                                                         ".");
 892                                         if (!tmp_fname) {
 893                                                 return NT_STATUS_NO_MEMORY;
 894                                         }
 895                                 }
 896
 897 #ifdef REALPATH_TAKES_NULL
 898                                 resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,NULL);
 899 #else
 900                                 resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,resolved_name_buf);
 901 #endif
 902                                 if (!resolved_name) {
 903                                         DEBUG(3,("reduce_name: couldn't get realpath for %s\n", fname));
 904                                         return map_nt_error_from_unix(errno);
 905                                 }
 906                                 tmp_fname = talloc_asprintf(ctx,
 907                                                 "%s/%s",
 908                                                 resolved_name,
 909                                                 last_component);
 910                                 if (!tmp_fname) {
 911                                         return NT_STATUS_NO_MEMORY;
 912                                 }
 913 #ifdef REALPATH_TAKES_NULL
 914                                 SAFE_FREE(resolved_name);
 915                                 resolved_name = SMB_STRDUP(tmp_fname);
 916                                 if (!resolved_name) {
 917                                         DEBUG(0,("reduce_name: malloc fail for %s\n", tmp_fname));
 918                                         return NT_STATUS_NO_MEMORY;
 919                                 }
 920 #else
 921                                 safe_strcpy(resolved_name_buf, tmp_fname, PATH_MAX);
 922                                 resolved_name = resolved_name_buf;
 923 #endif
 924                                 break;
 925                         }
 926                         default:
 927                                 DEBUG(1,("reduce_name: couldn't get realpath for %s\n", fname));
 928                                 return map_nt_error_from_unix(errno);
 929                 }
 930         }
 931
 932         DEBUG(10,("reduce_name realpath [%s] -> [%s]\n", fname, resolved_name));
 933
 934         if (*resolved_name != '/') {
 935                 DEBUG(0,("reduce_name: realpath doesn't return absolute paths !\n"));
 936                 if (free_resolved_name) {
 937                         SAFE_FREE(resolved_name);
 938                 }
 939                 return NT_STATUS_OBJECT_NAME_INVALID;
 940         }
 941
 942         /* Check for widelinks allowed. */
 943         if (!lp_widelinks(SNUM(conn)) && (strncmp(conn->connectpath, resolved_name, con_path_len) != 0)) {
 944                 DEBUG(2, ("reduce_name: Bad access attempt: %s is a symlink outside the share path", fname));
 945                 if (free_resolved_name) {
 946                         SAFE_FREE(resolved_name);
 947                 }
 948                 return NT_STATUS_ACCESS_DENIED;
 949         }
 950
 951         /* Check if we are allowing users to follow symlinks */
 952         /* Patch from David Clerc <David.Clerc@cui.unige.ch>
 953                 University of Geneva */
 954
 955 #ifdef S_ISLNK
 956         if (!lp_symlinks(SNUM(conn))) {
 957                 SMB_STRUCT_STAT statbuf;
 958                 if ( (SMB_VFS_LSTAT(conn,fname,&statbuf) != -1) &&
 959                                 (S_ISLNK(statbuf.st_mode)) ) {
 960                         if (free_resolved_name) {
 961                                 SAFE_FREE(resolved_name);
 962                         }
 963                         DEBUG(3,("reduce_name: denied: file path name %s is a symlink\n",resolved_name));
 964                         return NT_STATUS_ACCESS_DENIED;
 965                 }
 966         }
 967 #endif
 968
 969         DEBUG(3,("reduce_name: %s reduced to %s\n", fname, resolved_name));
 970         if (free_resolved_name) {
 971                 SAFE_FREE(resolved_name);
 972         }
 973         return NT_STATUS_OK;
 974 }