source3/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 #include "smbd/globals.h"
  27
  28 #undef DBGC_CLASS
  29 #define DBGC_CLASS DBGC_VFS
  30
  31 static_decl_vfs;
  32
  33 struct vfs_init_function_entry {
  34         char *name;
  35         const vfs_op_tuple *vfs_op_tuples;
  36         struct vfs_init_function_entry *prev, *next;
  37 };
  38
  39 /****************************************************************************
  40     maintain the list of available backends
  41 ****************************************************************************/
  42
  43 static struct vfs_init_function_entry *vfs_find_backend_entry(const char *name)
  44 {
  45         struct vfs_init_function_entry *entry = backends;
  46
  47         DEBUG(10, ("vfs_find_backend_entry called for %s\n", name));
  48
  49         while(entry) {
  50                 if (strcmp(entry->name, name)==0) return entry;
  51                 entry = entry->next;
  52         }
  53
  54         return NULL;
  55 }
  56
  57 NTSTATUS smb_register_vfs(int version, const char *name, const vfs_op_tuple *vfs_op_tuples)
  58 {
  59         struct vfs_init_function_entry *entry = backends;
  60
  61         if ((version != SMB_VFS_INTERFACE_VERSION)) {
  62                 DEBUG(0, ("Failed to register vfs module.\n"
  63                           "The module was compiled against SMB_VFS_INTERFACE_VERSION %d,\n"
  64                           "current SMB_VFS_INTERFACE_VERSION is %d.\n"
  65                           "Please recompile against the current Samba Version!\n",
  66                           version, SMB_VFS_INTERFACE_VERSION));
  67                 return NT_STATUS_OBJECT_TYPE_MISMATCH;
  68         }
  69
  70         if (!name || !name[0] || !vfs_op_tuples) {
  71                 DEBUG(0,("smb_register_vfs() called with NULL pointer or empty name!\n"));
  72                 return NT_STATUS_INVALID_PARAMETER;
  73         }
  74
  75         if (vfs_find_backend_entry(name)) {
  76                 DEBUG(0,("VFS module %s already loaded!\n", name));
  77                 return NT_STATUS_OBJECT_NAME_COLLISION;
  78         }
  79
  80         entry = SMB_XMALLOC_P(struct vfs_init_function_entry);
  81         entry->name = smb_xstrdup(name);
  82         entry->vfs_op_tuples = vfs_op_tuples;
  83
  84         DLIST_ADD(backends, entry);
  85         DEBUG(5, ("Successfully added vfs backend '%s'\n", name));
  86         return NT_STATUS_OK;
  87 }
  88
  89 /****************************************************************************
  90   initialise default vfs hooks
  91 ****************************************************************************/
  92
  93 static void vfs_init_default(connection_struct *conn)
  94 {
  95         DEBUG(3, ("Initialising default vfs hooks\n"));
  96         vfs_init_custom(conn, DEFAULT_VFS_MODULE_NAME);
  97 }
  98
  99 /****************************************************************************
 100   initialise custom vfs hooks
 101  ****************************************************************************/
 102
 103 static inline void vfs_set_operation(struct vfs_ops * vfs, vfs_op_type which,
 104                                 struct vfs_handle_struct * handle, void * op)
 105 {
 106         ((struct vfs_handle_struct **)&vfs->handles)[which] = handle;
 107         ((void **)(void *)&vfs->ops)[which] = op;
 108 }
 109
 110 bool vfs_init_custom(connection_struct *conn, const char *vfs_object)
 111 {
 112         const vfs_op_tuple *ops;
 113         char *module_path = NULL;
 114         char *module_name = NULL;
 115         char *module_param = NULL, *p;
 116         int i;
 117         vfs_handle_struct *handle;
 118         const struct vfs_init_function_entry *entry;
 119
 120         if (!conn||!vfs_object||!vfs_object[0]) {
 121                 DEBUG(0,("vfs_init_custon() called with NULL pointer or emtpy vfs_object!\n"));
 122                 return False;
 123         }
 124
 125         if(!backends) {
 126                 static_init_vfs;
 127         }
 128
 129         DEBUG(3, ("Initialising custom vfs hooks from [%s]\n", vfs_object));
 130
 131         module_path = smb_xstrdup(vfs_object);
 132
 133         p = strchr_m(module_path, ':');
 134
 135         if (p) {
 136                 *p = 0;
 137                 module_param = p+1;
 138                 trim_char(module_param, ' ', ' ');
 139         }
 140
 141         trim_char(module_path, ' ', ' ');
 142
 143         module_name = smb_xstrdup(module_path);
 144
 145         if ((module_name[0] == '/') &&
 146             (strcmp(module_path, DEFAULT_VFS_MODULE_NAME) != 0)) {
 147
 148                 /*
 149                  * Extract the module name from the path. Just use the base
 150                  * name of the last path component.
 151                  */
 152
 153                 SAFE_FREE(module_name);
 154                 module_name = smb_xstrdup(strrchr_m(module_path, '/')+1);
 155
 156                 p = strchr_m(module_name, '.');
 157
 158                 if (p != NULL) {
 159                         *p = '\0';
 160                 }
 161         }
 162
 163         /* First, try to load the module with the new module system */
 164         if((entry = vfs_find_backend_entry(module_name)) ||
 165            (NT_STATUS_IS_OK(smb_probe_module("vfs", module_path)) &&
 166                 (entry = vfs_find_backend_entry(module_name)))) {
 167
 168                 DEBUGADD(5,("Successfully loaded vfs module [%s] with the new modules system\n", vfs_object));
 169
 170                 if ((ops = entry->vfs_op_tuples) == NULL) {
 171                         DEBUG(0, ("entry->vfs_op_tuples==NULL for [%s] failed\n", vfs_object));
 172                         goto fail;
 173                 }
 174         } else {
 175                 DEBUG(0,("Can't find a vfs module [%s]\n",vfs_object));
 176                 goto fail;
 177         }
 178
 179         handle = TALLOC_ZERO_P(conn, vfs_handle_struct);
 180         if (!handle) {
 181                 DEBUG(0,("TALLOC_ZERO() failed!\n"));
 182                 goto fail;
 183         }
 184         memcpy(&handle->vfs_next, &conn->vfs, sizeof(struct vfs_ops));
 185         handle->conn = conn;
 186         if (module_param) {
 187                 handle->param = talloc_strdup(conn, module_param);
 188         }
 189         DLIST_ADD(conn->vfs_handles, handle);
 190
 191         for(i=0; ops[i].op != NULL; i++) {
 192                 DEBUG(5, ("Checking operation #%d (type %d, layer %d)\n", i, ops[i].type, ops[i].layer));
 193                 if(ops[i].layer == SMB_VFS_LAYER_OPAQUE) {
 194                         /* If this operation was already made opaque by different module, it
 195                          * will be overridden here.
 196                          */
 197                         DEBUGADD(5, ("Making operation type %d opaque [module %s]\n", ops[i].type, vfs_object));
 198                         vfs_set_operation(&conn->vfs_opaque, ops[i].type, handle, ops[i].op);
 199                 }
 200                 /* Change current VFS disposition*/
 201                 DEBUGADD(5, ("Accepting operation type %d from module %s\n", ops[i].type, vfs_object));
 202                 vfs_set_operation(&conn->vfs, ops[i].type, handle, ops[i].op);
 203         }
 204
 205         SAFE_FREE(module_path);
 206         SAFE_FREE(module_name);
 207         return True;
 208
 209  fail:
 210         SAFE_FREE(module_path);
 211         SAFE_FREE(module_name);
 212         return False;
 213 }
 214
 215 /*****************************************************************
 216  Allow VFS modules to extend files_struct with VFS-specific state.
 217  This will be ok for small numbers of extensions, but might need to
 218  be refactored if it becomes more widely used.
 219 ******************************************************************/
 220
 221 #define EXT_DATA_AREA(e) ((uint8 *)(e) + sizeof(struct vfs_fsp_data))
 222
 223 void *vfs_add_fsp_extension_notype(vfs_handle_struct *handle,
 224                                    files_struct *fsp, size_t ext_size,
 225                                    void (*destroy_fn)(void *p_data))
 226 {
 227         struct vfs_fsp_data *ext;
 228         void * ext_data;
 229
 230         /* Prevent VFS modules adding multiple extensions. */
 231         if ((ext_data = vfs_fetch_fsp_extension(handle, fsp))) {
 232                 return ext_data;
 233         }
 234
 235         ext = (struct vfs_fsp_data *)TALLOC_ZERO(
 236                 handle->conn, sizeof(struct vfs_fsp_data) + ext_size);
 237         if (ext == NULL) {
 238                 return NULL;
 239         }
 240
 241         ext->owner = handle;
 242         ext->next = fsp->vfs_extension;
 243         ext->destroy = destroy_fn;
 244         fsp->vfs_extension = ext;
 245         return EXT_DATA_AREA(ext);
 246 }
 247
 248 void vfs_remove_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
 249 {
 250         struct vfs_fsp_data *curr;
 251         struct vfs_fsp_data *prev;
 252
 253         for (curr = fsp->vfs_extension, prev = NULL;
 254              curr;
 255              prev = curr, curr = curr->next) {
 256                 if (curr->owner == handle) {
 257                     if (prev) {
 258                             prev->next = curr->next;
 259                     } else {
 260                             fsp->vfs_extension = curr->next;
 261                     }
 262                     if (curr->destroy) {
 263                             curr->destroy(EXT_DATA_AREA(curr));
 264                     }
 265                     TALLOC_FREE(curr);
 266                     return;
 267                 }
 268         }
 269 }
 270
 271 void *vfs_memctx_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
 272 {
 273         struct vfs_fsp_data *head;
 274
 275         for (head = fsp->vfs_extension; head; head = head->next) {
 276                 if (head->owner == handle) {
 277                         return head;
 278                 }
 279         }
 280
 281         return NULL;
 282 }
 283
 284 void *vfs_fetch_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
 285 {
 286         struct vfs_fsp_data *head;
 287
 288         head = (struct vfs_fsp_data *)vfs_memctx_fsp_extension(handle, fsp);
 289         if (head != NULL) {
 290                 return EXT_DATA_AREA(head);
 291         }
 292
 293         return NULL;
 294 }
 295
 296 #undef EXT_DATA_AREA
 297
 298 /*****************************************************************
 299  Generic VFS init.
 300 ******************************************************************/
 301
 302 bool smbd_vfs_init(connection_struct *conn)
 303 {
 304         const char **vfs_objects;
 305         unsigned int i = 0;
 306         int j = 0;
 307
 308         /* Normal share - initialise with disk access functions */
 309         vfs_init_default(conn);
 310         vfs_objects = lp_vfs_objects(SNUM(conn));
 311
 312         /* Override VFS functions if 'vfs object' was not specified*/
 313         if (!vfs_objects || !vfs_objects[0])
 314                 return True;
 315
 316         for (i=0; vfs_objects[i] ;) {
 317                 i++;
 318         }
 319
 320         for (j=i-1; j >= 0; j--) {
 321                 if (!vfs_init_custom(conn, vfs_objects[j])) {
 322                         DEBUG(0, ("smbd_vfs_init: vfs_init_custom failed for %s\n", vfs_objects[j]));
 323                         return False;
 324                 }
 325         }
 326         return True;
 327 }
 328
 329 /*******************************************************************
 330  Check if directory exists.
 331 ********************************************************************/
 332
 333 bool vfs_directory_exist(connection_struct *conn, const char *dname, SMB_STRUCT_STAT *st)
 334 {
 335         SMB_STRUCT_STAT st2;
 336         bool ret;
 337
 338         if (!st)
 339                 st = &st2;
 340
 341         if (SMB_VFS_STAT(conn,dname,st) != 0)
 342                 return(False);
 343
 344         ret = S_ISDIR(st->st_mode);
 345         if(!ret)
 346                 errno = ENOTDIR;
 347
 348         return ret;
 349 }
 350
 351 /*******************************************************************
 352  Check if an object exists in the vfs.
 353 ********************************************************************/
 354
 355 bool vfs_object_exist(connection_struct *conn,const char *fname,SMB_STRUCT_STAT *sbuf)
 356 {
 357         SMB_STRUCT_STAT st;
 358
 359         if (!sbuf)
 360                 sbuf = &st;
 361
 362         ZERO_STRUCTP(sbuf);
 363
 364         if (SMB_VFS_STAT(conn,fname,sbuf) == -1)
 365                 return(False);
 366         return True;
 367 }
 368
 369 /*******************************************************************
 370  Check if a file exists in the vfs.
 371 ********************************************************************/
 372
 373 bool vfs_file_exist(connection_struct *conn, const char *fname,SMB_STRUCT_STAT *sbuf)
 374 {
 375         SMB_STRUCT_STAT st;
 376
 377         if (!sbuf)
 378                 sbuf = &st;
 379
 380         ZERO_STRUCTP(sbuf);
 381
 382         if (SMB_VFS_STAT(conn,fname,sbuf) == -1)
 383                 return False;
 384         return(S_ISREG(sbuf->st_mode));
 385 }
 386
 387 /****************************************************************************
 388  Read data from fsp on the vfs. (note: EINTR re-read differs from vfs_write_data)
 389 ****************************************************************************/
 390
 391 ssize_t vfs_read_data(files_struct *fsp, char *buf, size_t byte_count)
 392 {
 393         size_t total=0;
 394
 395         while (total < byte_count)
 396         {
 397                 ssize_t ret = SMB_VFS_READ(fsp, buf + total,
 398                                            byte_count - total);
 399
 400                 if (ret == 0) return total;
 401                 if (ret == -1) {
 402                         if (errno == EINTR)
 403                                 continue;
 404                         else
 405                                 return -1;
 406                 }
 407                 total += ret;
 408         }
 409         return (ssize_t)total;
 410 }
 411
 412 ssize_t vfs_pread_data(files_struct *fsp, char *buf,
 413                 size_t byte_count, SMB_OFF_T offset)
 414 {
 415         size_t total=0;
 416
 417         while (total < byte_count)
 418         {
 419                 ssize_t ret = SMB_VFS_PREAD(fsp, buf + total,
 420                                         byte_count - total, offset + total);
 421
 422                 if (ret == 0) return total;
 423                 if (ret == -1) {
 424                         if (errno == EINTR)
 425                                 continue;
 426                         else
 427                                 return -1;
 428                 }
 429                 total += ret;
 430         }
 431         return (ssize_t)total;
 432 }
 433
 434 /****************************************************************************
 435  Write data to a fd on the vfs.
 436 ****************************************************************************/
 437
 438 ssize_t vfs_write_data(struct smb_request *req,
 439                         files_struct *fsp,
 440                         const char *buffer,
 441                         size_t N)
 442 {
 443         size_t total=0;
 444         ssize_t ret;
 445
 446         if (req && req->unread_bytes) {
 447                 SMB_ASSERT(req->unread_bytes == N);
 448                 /* VFS_RECVFILE must drain the socket
 449                  * before returning. */
 450                 req->unread_bytes = 0;
 451                 return SMB_VFS_RECVFILE(smbd_server_fd(),
 452                                         fsp,
 453                                         (SMB_OFF_T)-1,
 454                                         N);
 455         }
 456
 457         while (total < N) {
 458                 ret = SMB_VFS_WRITE(fsp, buffer + total, N - total);
 459
 460                 if (ret == -1)
 461                         return -1;
 462                 if (ret == 0)
 463                         return total;
 464
 465                 total += ret;
 466         }
 467         return (ssize_t)total;
 468 }
 469
 470 ssize_t vfs_pwrite_data(struct smb_request *req,
 471                         files_struct *fsp,
 472                         const char *buffer,
 473                         size_t N,
 474                         SMB_OFF_T offset)
 475 {
 476         size_t total=0;
 477         ssize_t ret;
 478
 479         if (req && req->unread_bytes) {
 480                 SMB_ASSERT(req->unread_bytes == N);
 481                 /* VFS_RECVFILE must drain the socket
 482                  * before returning. */
 483                 req->unread_bytes = 0;
 484                 return SMB_VFS_RECVFILE(smbd_server_fd(),
 485                                         fsp,
 486                                         offset,
 487                                         N);
 488         }
 489
 490         while (total < N) {
 491                 ret = SMB_VFS_PWRITE(fsp, buffer + total, N - total,
 492                                      offset + total);
 493
 494                 if (ret == -1)
 495                         return -1;
 496                 if (ret == 0)
 497                         return total;
 498
 499                 total += ret;
 500         }
 501         return (ssize_t)total;
 502 }
 503 /****************************************************************************
 504  An allocate file space call using the vfs interface.
 505  Allocates space for a file from a filedescriptor.
 506  Returns 0 on success, -1 on failure.
 507 ****************************************************************************/
 508
 509 int vfs_allocate_file_space(files_struct *fsp, uint64_t len)
 510 {
 511         int ret;
 512         SMB_STRUCT_STAT st;
 513         connection_struct *conn = fsp->conn;
 514         uint64_t space_avail;
 515         uint64_t bsize,dfree,dsize;
 516
 517         release_level_2_oplocks_on_change(fsp);
 518
 519         /*
 520          * Actually try and commit the space on disk....
 521          */
 522
 523         DEBUG(10,("vfs_allocate_file_space: file %s, len %.0f\n", fsp->fsp_name, (double)len ));
 524
 525         if (((SMB_OFF_T)len) < 0) {
 526                 DEBUG(0,("vfs_allocate_file_space: %s negative len requested.\n", fsp->fsp_name ));
 527                 errno = EINVAL;
 528                 return -1;
 529         }
 530
 531         ret = SMB_VFS_FSTAT(fsp, &st);
 532         if (ret == -1)
 533                 return ret;
 534
 535         if (len == (uint64_t)st.st_size)
 536                 return 0;
 537
 538         if (len < (uint64_t)st.st_size) {
 539                 /* Shrink - use ftruncate. */
 540
 541                 DEBUG(10,("vfs_allocate_file_space: file %s, shrink. Current size %.0f\n",
 542                                 fsp->fsp_name, (double)st.st_size ));
 543
 544                 flush_write_cache(fsp, SIZECHANGE_FLUSH);
 545                 if ((ret = SMB_VFS_FTRUNCATE(fsp, (SMB_OFF_T)len)) != -1) {
 546                         set_filelen_write_cache(fsp, len);
 547                 }
 548                 return ret;
 549         }
 550
 551         /* Grow - we need to test if we have enough space. */
 552
 553         if (!lp_strict_allocate(SNUM(fsp->conn)))
 554                 return 0;
 555
 556         len -= st.st_size;
 557         len /= 1024; /* Len is now number of 1k blocks needed. */
 558         space_avail = get_dfree_info(conn,fsp->fsp_name,False,&bsize,&dfree,&dsize);
 559         if (space_avail == (uint64_t)-1) {
 560                 return -1;
 561         }
 562
 563         DEBUG(10,("vfs_allocate_file_space: file %s, grow. Current size %.0f, needed blocks = %.0f, space avail = %.0f\n",
 564                         fsp->fsp_name, (double)st.st_size, (double)len, (double)space_avail ));
 565
 566         if (len > space_avail) {
 567                 errno = ENOSPC;
 568                 return -1;
 569         }
 570
 571         return 0;
 572 }
 573
 574 /****************************************************************************
 575  A vfs set_filelen call.
 576  set the length of a file from a filedescriptor.
 577  Returns 0 on success, -1 on failure.
 578 ****************************************************************************/
 579
 580 int vfs_set_filelen(files_struct *fsp, SMB_OFF_T len)
 581 {
 582         int ret;
 583
 584         release_level_2_oplocks_on_change(fsp);
 585         DEBUG(10,("vfs_set_filelen: ftruncate %s to len %.0f\n", fsp->fsp_name, (double)len));
 586         flush_write_cache(fsp, SIZECHANGE_FLUSH);
 587         if ((ret = SMB_VFS_FTRUNCATE(fsp, len)) != -1) {
 588                 set_filelen_write_cache(fsp, len);
 589                 notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
 590                              FILE_NOTIFY_CHANGE_SIZE
 591                              | FILE_NOTIFY_CHANGE_ATTRIBUTES,
 592                              fsp->fsp_name);
 593         }
 594
 595         return ret;
 596 }
 597
 598 /****************************************************************************
 599  A vfs fill sparse call.
 600  Writes zeros from the end of file to len, if len is greater than EOF.
 601  Used only by strict_sync.
 602  Returns 0 on success, -1 on failure.
 603 ****************************************************************************/
 604
 605 #define SPARSE_BUF_WRITE_SIZE (32*1024)
 606
 607 int vfs_fill_sparse(files_struct *fsp, SMB_OFF_T len)
 608 {
 609         int ret;
 610         SMB_STRUCT_STAT st;
 611         SMB_OFF_T offset;
 612         size_t total;
 613         size_t num_to_write;
 614         ssize_t pwrite_ret;
 615
 616         release_level_2_oplocks_on_change(fsp);
 617         ret = SMB_VFS_FSTAT(fsp, &st);
 618         if (ret == -1) {
 619                 return ret;
 620         }
 621
 622         if (len <= st.st_size) {
 623                 return 0;
 624         }
 625
 626         DEBUG(10,("vfs_fill_sparse: write zeros in file %s from len %.0f to len %.0f (%.0f bytes)\n",
 627                 fsp->fsp_name, (double)st.st_size, (double)len, (double)(len - st.st_size)));
 628
 629         flush_write_cache(fsp, SIZECHANGE_FLUSH);
 630
 631         if (!sparse_buf) {
 632                 sparse_buf = SMB_CALLOC_ARRAY(char, SPARSE_BUF_WRITE_SIZE);
 633                 if (!sparse_buf) {
 634                         errno = ENOMEM;
 635                         return -1;
 636                 }
 637         }
 638
 639         offset = st.st_size;
 640         num_to_write = len - st.st_size;
 641         total = 0;
 642
 643         while (total < num_to_write) {
 644                 size_t curr_write_size = MIN(SPARSE_BUF_WRITE_SIZE, (num_to_write - total));
 645
 646                 pwrite_ret = SMB_VFS_PWRITE(fsp, sparse_buf, curr_write_size, offset + total);
 647                 if (pwrite_ret == -1) {
 648                         DEBUG(10,("vfs_fill_sparse: SMB_VFS_PWRITE for file %s failed with error %s\n",
 649                                 fsp->fsp_name, strerror(errno) ));
 650                         return -1;
 651                 }
 652                 if (pwrite_ret == 0) {
 653                         return 0;
 654                 }
 655
 656                 total += pwrite_ret;
 657         }
 658
 659         set_filelen_write_cache(fsp, len);
 660         return 0;
 661 }
 662
 663 /****************************************************************************
 664  Transfer some data (n bytes) between two file_struct's.
 665 ****************************************************************************/
 666
 667 static ssize_t vfs_read_fn(void *file, void *buf, size_t len)
 668 {
 669         struct files_struct *fsp = (struct files_struct *)file;
 670
 671         return SMB_VFS_READ(fsp, buf, len);
 672 }
 673
 674 static ssize_t vfs_write_fn(void *file, const void *buf, size_t len)
 675 {
 676         struct files_struct *fsp = (struct files_struct *)file;
 677
 678         return SMB_VFS_WRITE(fsp, buf, len);
 679 }
 680
 681 SMB_OFF_T vfs_transfer_file(files_struct *in, files_struct *out, SMB_OFF_T n)
 682 {
 683         return transfer_file_internal((void *)in, (void *)out, n,
 684                                       vfs_read_fn, vfs_write_fn);
 685 }
 686
 687 /*******************************************************************
 688  A vfs_readdir wrapper which just returns the file name.
 689 ********************************************************************/
 690
 691 char *vfs_readdirname(connection_struct *conn, void *p)
 692 {
 693         SMB_STRUCT_DIRENT *ptr= NULL;
 694         char *dname;
 695
 696         if (!p)
 697                 return(NULL);
 698
 699         ptr = SMB_VFS_READDIR(conn, (DIR *)p);
 700         if (!ptr)
 701                 return(NULL);
 702
 703         dname = ptr->d_name;
 704
 705 #ifdef NEXT2
 706         if (telldir(p) < 0)
 707                 return(NULL);
 708 #endif
 709
 710 #ifdef HAVE_BROKEN_READDIR_NAME
 711         /* using /usr/ucb/cc is BAD */
 712         dname = dname - 2;
 713 #endif
 714
 715         return(dname);
 716 }
 717
 718 /*******************************************************************
 719  A wrapper for vfs_chdir().
 720 ********************************************************************/
 721
 722 int vfs_ChDir(connection_struct *conn, const char *path)
 723 {
 724         int res;
 725
 726         if (!LastDir) {
 727                 LastDir = SMB_STRDUP("");
 728         }
 729
 730         if (strcsequal(path,"."))
 731                 return(0);
 732
 733         if (*path == '/' && strcsequal(LastDir,path))
 734                 return(0);
 735
 736         DEBUG(4,("vfs_ChDir to %s\n",path));
 737
 738         res = SMB_VFS_CHDIR(conn,path);
 739         if (!res) {
 740                 SAFE_FREE(LastDir);
 741                 LastDir = SMB_STRDUP(path);
 742         }
 743         return(res);
 744 }
 745
 746 /*******************************************************************
 747  Return the absolute current directory path - given a UNIX pathname.
 748  Note that this path is returned in DOS format, not UNIX
 749  format. Note this can be called with conn == NULL.
 750 ********************************************************************/
 751
 752 struct getwd_cache_key {
 753         SMB_DEV_T dev;
 754         SMB_INO_T ino;
 755 };
 756
 757 char *vfs_GetWd(TALLOC_CTX *ctx, connection_struct *conn)
 758 {
 759         char s[PATH_MAX+1];
 760         SMB_STRUCT_STAT st, st2;
 761         char *result;
 762         DATA_BLOB cache_value;
 763         struct getwd_cache_key key;
 764
 765         *s = 0;
 766
 767         if (!lp_getwd_cache()) {
 768                 goto nocache;
 769         }
 770
 771         SET_STAT_INVALID(st);
 772
 773         if (SMB_VFS_STAT(conn, ".",&st) == -1) {
 774                 /*
 775                  * Known to fail for root: the directory may be NFS-mounted
 776                  * and exported with root_squash (so has no root access).
 777                  */
 778                 DEBUG(1,("vfs_GetWd: couldn't stat \".\" error %s "
 779                          "(NFS problem ?)\n", strerror(errno) ));
 780                 goto nocache;
 781         }
 782
 783         ZERO_STRUCT(key); /* unlikely, but possible padding */
 784         key.dev = st.st_dev;
 785         key.ino = st.st_ino;
 786
 787         if (!memcache_lookup(smbd_memcache(), GETWD_CACHE,
 788                              data_blob_const(&key, sizeof(key)),
 789                              &cache_value)) {
 790                 goto nocache;
 791         }
 792
 793         SMB_ASSERT((cache_value.length > 0)
 794                    && (cache_value.data[cache_value.length-1] == '\0'));
 795
 796         if ((SMB_VFS_STAT(conn, (char *)cache_value.data, &st2) == 0)
 797             && (st.st_dev == st2.st_dev) && (st.st_ino == st2.st_ino)
 798             && (S_ISDIR(st.st_mode))) {
 799                 /*
 800                  * Ok, we're done
 801                  */
 802                 result = talloc_strdup(ctx, (char *)cache_value.data);
 803                 if (result == NULL) {
 804                         errno = ENOMEM;
 805                 }
 806                 return result;
 807         }
 808
 809  nocache:
 810
 811         /*
 812          * We don't have the information to hand so rely on traditional
 813          * methods. The very slow getcwd, which spawns a process on some
 814          * systems, or the not quite so bad getwd.
 815          */
 816
 817         if (!SMB_VFS_GETWD(conn,s)) {
 818                 DEBUG(0, ("vfs_GetWd: SMB_VFS_GETWD call failed: %s\n",
 819                           strerror(errno)));
 820                 return NULL;
 821         }
 822
 823         if (lp_getwd_cache() && VALID_STAT(st)) {
 824                 ZERO_STRUCT(key); /* unlikely, but possible padding */
 825                 key.dev = st.st_dev;
 826                 key.ino = st.st_ino;
 827
 828                 memcache_add(smbd_memcache(), GETWD_CACHE,
 829                              data_blob_const(&key, sizeof(key)),
 830                              data_blob_const(s, strlen(s)+1));
 831         }
 832
 833         result = talloc_strdup(ctx, s);
 834         if (result == NULL) {
 835                 errno = ENOMEM;
 836         }
 837         return result;
 838 }
 839
 840 /*******************************************************************
 841  Reduce a file name, removing .. elements and checking that
 842  it is below dir in the heirachy. This uses realpath.
 843 ********************************************************************/
 844
 845 NTSTATUS check_reduced_name(connection_struct *conn, const char *fname)
 846 {
 847 #ifdef REALPATH_TAKES_NULL
 848         bool free_resolved_name = True;
 849 #else
 850         char resolved_name_buf[PATH_MAX+1];
 851         bool free_resolved_name = False;
 852 #endif
 853         char *resolved_name = NULL;
 854         size_t con_path_len = strlen(conn->connectpath);
 855         char *p = NULL;
 856
 857         DEBUG(3,("reduce_name [%s] [%s]\n", fname, conn->connectpath));
 858
 859 #ifdef REALPATH_TAKES_NULL
 860         resolved_name = SMB_VFS_REALPATH(conn,fname,NULL);
 861 #else
 862         resolved_name = SMB_VFS_REALPATH(conn,fname,resolved_name_buf);
 863 #endif
 864
 865         if (!resolved_name) {
 866                 switch (errno) {
 867                         case ENOTDIR:
 868                                 DEBUG(3,("reduce_name: Component not a directory in getting realpath for %s\n", fname));
 869                                 return map_nt_error_from_unix(errno);
 870                         case ENOENT:
 871                         {
 872                                 TALLOC_CTX *ctx = talloc_tos();
 873                                 char *tmp_fname = NULL;
 874                                 char *last_component = NULL;
 875                                 /* Last component didn't exist. Remove it and try and canonicalise the directory. */
 876
 877                                 tmp_fname = talloc_strdup(ctx, fname);
 878                                 if (!tmp_fname) {
 879                                         return NT_STATUS_NO_MEMORY;
 880                                 }
 881                                 p = strrchr_m(tmp_fname, '/');
 882                                 if (p) {
 883                                         *p++ = '\0';
 884                                         last_component = p;
 885                                 } else {
 886                                         last_component = tmp_fname;
 887                                         tmp_fname = talloc_strdup(ctx,
 888                                                         ".");
 889                                         if (!tmp_fname) {
 890                                                 return NT_STATUS_NO_MEMORY;
 891                                         }
 892                                 }
 893
 894 #ifdef REALPATH_TAKES_NULL
 895                                 resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,NULL);
 896 #else
 897                                 resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,resolved_name_buf);
 898 #endif
 899                                 if (!resolved_name) {
 900                                         DEBUG(3,("reduce_name: couldn't get realpath for %s\n", fname));
 901                                         return map_nt_error_from_unix(errno);
 902                                 }
 903                                 tmp_fname = talloc_asprintf(ctx,
 904                                                 "%s/%s",
 905                                                 resolved_name,
 906                                                 last_component);
 907                                 if (!tmp_fname) {
 908                                         return NT_STATUS_NO_MEMORY;
 909                                 }
 910 #ifdef REALPATH_TAKES_NULL
 911                                 SAFE_FREE(resolved_name);
 912                                 resolved_name = SMB_STRDUP(tmp_fname);
 913                                 if (!resolved_name) {
 914                                         DEBUG(0,("reduce_name: malloc fail for %s\n", tmp_fname));
 915                                         return NT_STATUS_NO_MEMORY;
 916                                 }
 917 #else
 918                                 safe_strcpy(resolved_name_buf, tmp_fname, PATH_MAX);
 919                                 resolved_name = resolved_name_buf;
 920 #endif
 921                                 break;
 922                         }
 923                         default:
 924                                 DEBUG(1,("reduce_name: couldn't get realpath for %s\n", fname));
 925                                 return map_nt_error_from_unix(errno);
 926                 }
 927         }
 928
 929         DEBUG(10,("reduce_name realpath [%s] -> [%s]\n", fname, resolved_name));
 930
 931         if (*resolved_name != '/') {
 932                 DEBUG(0,("reduce_name: realpath doesn't return absolute paths !\n"));
 933                 if (free_resolved_name) {
 934                         SAFE_FREE(resolved_name);
 935                 }
 936                 return NT_STATUS_OBJECT_NAME_INVALID;
 937         }
 938
 939         /* Check for widelinks allowed. */
 940         if (!lp_widelinks(SNUM(conn)) && (strncmp(conn->connectpath, resolved_name, con_path_len) != 0)) {
 941                 DEBUG(2, ("reduce_name: Bad access attempt: %s is a symlink outside the share path", fname));
 942                 if (free_resolved_name) {
 943                         SAFE_FREE(resolved_name);
 944                 }
 945                 return NT_STATUS_ACCESS_DENIED;
 946         }
 947
 948         /* Check if we are allowing users to follow symlinks */
 949         /* Patch from David Clerc <David.Clerc@cui.unige.ch>
 950                 University of Geneva */
 951
 952 #ifdef S_ISLNK
 953         if (!lp_symlinks(SNUM(conn))) {
 954                 SMB_STRUCT_STAT statbuf;
 955                 if ( (SMB_VFS_LSTAT(conn,fname,&statbuf) != -1) &&
 956                                 (S_ISLNK(statbuf.st_mode)) ) {
 957                         if (free_resolved_name) {
 958                                 SAFE_FREE(resolved_name);
 959                         }
 960                         DEBUG(3,("reduce_name: denied: file path name %s is a symlink\n",resolved_name));
 961                         return NT_STATUS_ACCESS_DENIED;
 962                 }
 963         }
 964 #endif
 965
 966         DEBUG(3,("reduce_name: %s reduced to %s\n", fname, resolved_name));
 967         if (free_resolved_name) {
 968                 SAFE_FREE(resolved_name);
 969         }
 970         return NT_STATUS_OK;
 971 }