53a0001515dc36e3bf9d4413a2956751a82f4f07
[kai/samba.git] / 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
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                                         fsp->fh->fd,
449                                         (SMB_OFF_T)-1,
450                                         N);
451         }
452
453         while (total < N) {
454                 ret = SMB_VFS_WRITE(fsp,fsp->fh->fd,buffer + total,N - total);
455
456                 if (ret == -1)
457                         return -1;
458                 if (ret == 0)
459                         return total;
460
461                 total += ret;
462         }
463         return (ssize_t)total;
464 }
465
466 ssize_t vfs_pwrite_data(struct smb_request *req,
467                         files_struct *fsp,
468                         const char *buffer,
469                         size_t N,
470                         SMB_OFF_T offset)
471 {
472         size_t total=0;
473         ssize_t ret;
474
475         if (req && req->unread_bytes) {
476                 SMB_ASSERT(req->unread_bytes == N);
477                 /* VFS_RECVFILE must drain the socket
478                  * before returning. */
479                 req->unread_bytes = 0;
480                 return SMB_VFS_RECVFILE(smbd_server_fd(),
481                                         fsp,
482                                         fsp->fh->fd,
483                                         offset,
484                                         N);
485         }
486
487         while (total < N) {
488                 ret = SMB_VFS_PWRITE(fsp, buffer + total, N - total,
489                                      offset + total);
490
491                 if (ret == -1)
492                         return -1;
493                 if (ret == 0)
494                         return total;
495
496                 total += ret;
497         }
498         return (ssize_t)total;
499 }
500 /****************************************************************************
501  An allocate file space call using the vfs interface.
502  Allocates space for a file from a filedescriptor.
503  Returns 0 on success, -1 on failure.
504 ****************************************************************************/
505
506 int vfs_allocate_file_space(files_struct *fsp, SMB_BIG_UINT len)
507 {
508         int ret;
509         SMB_STRUCT_STAT st;
510         connection_struct *conn = fsp->conn;
511         SMB_BIG_UINT space_avail;
512         SMB_BIG_UINT bsize,dfree,dsize;
513
514         release_level_2_oplocks_on_change(fsp);
515
516         /*
517          * Actually try and commit the space on disk....
518          */
519
520         DEBUG(10,("vfs_allocate_file_space: file %s, len %.0f\n", fsp->fsp_name, (double)len ));
521
522         if (((SMB_OFF_T)len) < 0) {
523                 DEBUG(0,("vfs_allocate_file_space: %s negative len requested.\n", fsp->fsp_name ));
524                 errno = EINVAL;
525                 return -1;
526         }
527
528         ret = SMB_VFS_FSTAT(fsp, &st);
529         if (ret == -1)
530                 return ret;
531
532         if (len == (SMB_BIG_UINT)st.st_size)
533                 return 0;
534
535         if (len < (SMB_BIG_UINT)st.st_size) {
536                 /* Shrink - use ftruncate. */
537
538                 DEBUG(10,("vfs_allocate_file_space: file %s, shrink. Current size %.0f\n",
539                                 fsp->fsp_name, (double)st.st_size ));
540
541                 flush_write_cache(fsp, SIZECHANGE_FLUSH);
542                 if ((ret = SMB_VFS_FTRUNCATE(fsp, (SMB_OFF_T)len)) != -1) {
543                         set_filelen_write_cache(fsp, len);
544                 }
545                 return ret;
546         }
547
548         /* Grow - we need to test if we have enough space. */
549
550         if (!lp_strict_allocate(SNUM(fsp->conn)))
551                 return 0;
552
553         len -= st.st_size;
554         len /= 1024; /* Len is now number of 1k blocks needed. */
555         space_avail = get_dfree_info(conn,fsp->fsp_name,False,&bsize,&dfree,&dsize);
556         if (space_avail == (SMB_BIG_UINT)-1) {
557                 return -1;
558         }
559
560         DEBUG(10,("vfs_allocate_file_space: file %s, grow. Current size %.0f, needed blocks = %.0f, space avail = %.0f\n",
561                         fsp->fsp_name, (double)st.st_size, (double)len, (double)space_avail ));
562
563         if (len > space_avail) {
564                 errno = ENOSPC;
565                 return -1;
566         }
567
568         return 0;
569 }
570
571 /****************************************************************************
572  A vfs set_filelen call.
573  set the length of a file from a filedescriptor.
574  Returns 0 on success, -1 on failure.
575 ****************************************************************************/
576
577 int vfs_set_filelen(files_struct *fsp, SMB_OFF_T len)
578 {
579         int ret;
580
581         release_level_2_oplocks_on_change(fsp);
582         DEBUG(10,("vfs_set_filelen: ftruncate %s to len %.0f\n", fsp->fsp_name, (double)len));
583         flush_write_cache(fsp, SIZECHANGE_FLUSH);
584         if ((ret = SMB_VFS_FTRUNCATE(fsp, len)) != -1) {
585                 set_filelen_write_cache(fsp, len);
586                 notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
587                              FILE_NOTIFY_CHANGE_SIZE
588                              | FILE_NOTIFY_CHANGE_ATTRIBUTES,
589                              fsp->fsp_name);
590         }
591
592         return ret;
593 }
594
595 /****************************************************************************
596  A vfs fill sparse call.
597  Writes zeros from the end of file to len, if len is greater than EOF.
598  Used only by strict_sync.
599  Returns 0 on success, -1 on failure.
600 ****************************************************************************/
601
602 static char *sparse_buf;
603 #define SPARSE_BUF_WRITE_SIZE (32*1024)
604
605 int vfs_fill_sparse(files_struct *fsp, SMB_OFF_T len)
606 {
607         int ret;
608         SMB_STRUCT_STAT st;
609         SMB_OFF_T offset;
610         size_t total;
611         size_t num_to_write;
612         ssize_t pwrite_ret;
613
614         release_level_2_oplocks_on_change(fsp);
615         ret = SMB_VFS_FSTAT(fsp, &st);
616         if (ret == -1) {
617                 return ret;
618         }
619
620         if (len <= st.st_size) {
621                 return 0;
622         }
623
624         DEBUG(10,("vfs_fill_sparse: write zeros in file %s from len %.0f to len %.0f (%.0f bytes)\n",
625                 fsp->fsp_name, (double)st.st_size, (double)len, (double)(len - st.st_size)));
626
627         flush_write_cache(fsp, SIZECHANGE_FLUSH);
628
629         if (!sparse_buf) {
630                 sparse_buf = SMB_CALLOC_ARRAY(char, SPARSE_BUF_WRITE_SIZE);
631                 if (!sparse_buf) {
632                         errno = ENOMEM;
633                         return -1;
634                 }
635         }
636
637         offset = st.st_size;
638         num_to_write = len - st.st_size;
639         total = 0;
640
641         while (total < num_to_write) {
642                 size_t curr_write_size = MIN(SPARSE_BUF_WRITE_SIZE, (num_to_write - total));
643
644                 pwrite_ret = SMB_VFS_PWRITE(fsp, sparse_buf, curr_write_size, offset + total);
645                 if (pwrite_ret == -1) {
646                         DEBUG(10,("vfs_fill_sparse: SMB_VFS_PWRITE for file %s failed with error %s\n",
647                                 fsp->fsp_name, strerror(errno) ));
648                         return -1;
649                 }
650                 if (pwrite_ret == 0) {
651                         return 0;
652                 }
653
654                 total += pwrite_ret;
655         }
656
657         set_filelen_write_cache(fsp, len);
658         return 0;
659 }
660
661 /****************************************************************************
662  Transfer some data (n bytes) between two file_struct's.
663 ****************************************************************************/
664
665 static ssize_t vfs_read_fn(void *file, void *buf, size_t len)
666 {
667         struct files_struct *fsp = (struct files_struct *)file;
668
669         return SMB_VFS_READ(fsp, buf, len);
670 }
671
672 static ssize_t vfs_write_fn(void *file, const void *buf, size_t len)
673 {
674         struct files_struct *fsp = (struct files_struct *)file;
675
676         return SMB_VFS_WRITE(fsp, fsp->fh->fd, buf, len);
677 }
678
679 SMB_OFF_T vfs_transfer_file(files_struct *in, files_struct *out, SMB_OFF_T n)
680 {
681         return transfer_file_internal((void *)in, (void *)out, n,
682                                       vfs_read_fn, vfs_write_fn);
683 }
684
685 /*******************************************************************
686  A vfs_readdir wrapper which just returns the file name.
687 ********************************************************************/
688
689 char *vfs_readdirname(connection_struct *conn, void *p)
690 {
691         SMB_STRUCT_DIRENT *ptr= NULL;
692         char *dname;
693
694         if (!p)
695                 return(NULL);
696
697         ptr = SMB_VFS_READDIR(conn, (DIR *)p);
698         if (!ptr)
699                 return(NULL);
700
701         dname = ptr->d_name;
702
703 #ifdef NEXT2
704         if (telldir(p) < 0)
705                 return(NULL);
706 #endif
707
708 #ifdef HAVE_BROKEN_READDIR_NAME
709         /* using /usr/ucb/cc is BAD */
710         dname = dname - 2;
711 #endif
712
713         return(dname);
714 }
715
716 /*******************************************************************
717  A wrapper for vfs_chdir().
718 ********************************************************************/
719
720 int vfs_ChDir(connection_struct *conn, const char *path)
721 {
722         int res;
723         static char *LastDir = NULL;
724
725         if (!LastDir) {
726                 LastDir = SMB_STRDUP("");
727         }
728
729         if (strcsequal(path,"."))
730                 return(0);
731
732         if (*path == '/' && strcsequal(LastDir,path))
733                 return(0);
734
735         DEBUG(4,("vfs_ChDir to %s\n",path));
736
737         res = SMB_VFS_CHDIR(conn,path);
738         if (!res) {
739                 SAFE_FREE(LastDir);
740                 LastDir = SMB_STRDUP(path);
741         }
742         return(res);
743 }
744
745 /*******************************************************************
746  Return the absolute current directory path - given a UNIX pathname.
747  Note that this path is returned in DOS format, not UNIX
748  format. Note this can be called with conn == NULL.
749 ********************************************************************/
750
751 struct getwd_cache_key {
752         SMB_DEV_T dev;
753         SMB_INO_T ino;
754 };
755
756 char *vfs_GetWd(TALLOC_CTX *ctx, connection_struct *conn)
757 {
758         char s[PATH_MAX+1];
759         SMB_STRUCT_STAT st, st2;
760         char *result;
761         DATA_BLOB cache_value;
762         struct getwd_cache_key key;
763
764         *s = 0;
765
766         if (!lp_getwd_cache()) {
767                 goto nocache;
768         }
769
770         SET_STAT_INVALID(st);
771
772         if (SMB_VFS_STAT(conn, ".",&st) == -1) {
773                 /*
774                  * Known to fail for root: the directory may be NFS-mounted
775                  * and exported with root_squash (so has no root access).
776                  */
777                 DEBUG(1,("vfs_GetWd: couldn't stat \".\" error %s "
778                          "(NFS problem ?)\n", strerror(errno) ));
779                 goto nocache;
780         }
781
782         ZERO_STRUCT(key); /* unlikely, but possible padding */
783         key.dev = st.st_dev;
784         key.ino = st.st_ino;
785
786         if (!memcache_lookup(smbd_memcache(), GETWD_CACHE,
787                              data_blob_const(&key, sizeof(key)),
788                              &cache_value)) {
789                 goto nocache;
790         }
791
792         SMB_ASSERT((cache_value.length > 0)
793                    && (cache_value.data[cache_value.length-1] == '\0'));
794
795         if ((SMB_VFS_STAT(conn, (char *)cache_value.data, &st2) == 0)
796             && (st.st_dev == st2.st_dev) && (st.st_ino == st2.st_ino)
797             && (S_ISDIR(st.st_mode))) {
798                 /*
799                  * Ok, we're done
800                  */
801                 result = talloc_strdup(ctx, (char *)cache_value.data);
802                 if (result == NULL) {
803                         errno = ENOMEM;
804                 }
805                 return result;
806         }
807
808  nocache:
809
810         /*
811          * We don't have the information to hand so rely on traditional
812          * methods. The very slow getcwd, which spawns a process on some
813          * systems, or the not quite so bad getwd.
814          */
815
816         if (!SMB_VFS_GETWD(conn,s)) {
817                 DEBUG(0, ("vfs_GetWd: SMB_VFS_GETWD call failed: %s\n",
818                           strerror(errno)));
819                 return NULL;
820         }
821
822         if (lp_getwd_cache() && VALID_STAT(st)) {
823                 ZERO_STRUCT(key); /* unlikely, but possible padding */
824                 key.dev = st.st_dev;
825                 key.ino = st.st_ino;
826
827                 memcache_add(smbd_memcache(), GETWD_CACHE,
828                              data_blob_const(&key, sizeof(key)),
829                              data_blob_const(s, strlen(s)+1));
830         }
831
832         result = talloc_strdup(ctx, s);
833         if (result == NULL) {
834                 errno = ENOMEM;
835         }
836         return result;
837 }
838
839 /*******************************************************************
840  Reduce a file name, removing .. elements and checking that
841  it is below dir in the heirachy. This uses realpath.
842 ********************************************************************/
843
844 NTSTATUS check_reduced_name(connection_struct *conn, const char *fname)
845 {
846 #ifdef REALPATH_TAKES_NULL
847         bool free_resolved_name = True;
848 #else
849         char resolved_name_buf[PATH_MAX+1];
850         bool free_resolved_name = False;
851 #endif
852         char *resolved_name = NULL;
853         size_t con_path_len = strlen(conn->connectpath);
854         char *p = NULL;
855
856         DEBUG(3,("reduce_name [%s] [%s]\n", fname, conn->connectpath));
857
858 #ifdef REALPATH_TAKES_NULL
859         resolved_name = SMB_VFS_REALPATH(conn,fname,NULL);
860 #else
861         resolved_name = SMB_VFS_REALPATH(conn,fname,resolved_name_buf);
862 #endif
863
864         if (!resolved_name) {
865                 switch (errno) {
866                         case ENOTDIR:
867                                 DEBUG(3,("reduce_name: Component not a directory in getting realpath for %s\n", fname));
868                                 return map_nt_error_from_unix(errno);
869                         case ENOENT:
870                         {
871                                 TALLOC_CTX *ctx = talloc_tos();
872                                 char *tmp_fname = NULL;
873                                 char *last_component = NULL;
874                                 /* Last component didn't exist. Remove it and try and canonicalise the directory. */
875
876                                 tmp_fname = talloc_strdup(ctx, fname);
877                                 if (!tmp_fname) {
878                                         return NT_STATUS_NO_MEMORY;
879                                 }
880                                 p = strrchr_m(tmp_fname, '/');
881                                 if (p) {
882                                         *p++ = '\0';
883                                         last_component = p;
884                                 } else {
885                                         last_component = tmp_fname;
886                                         tmp_fname = talloc_strdup(ctx,
887                                                         ".");
888                                         if (!tmp_fname) {
889                                                 return NT_STATUS_NO_MEMORY;
890                                         }
891                                 }
892
893 #ifdef REALPATH_TAKES_NULL
894                                 resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,NULL);
895 #else
896                                 resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,resolved_name_buf);
897 #endif
898                                 if (!resolved_name) {
899                                         DEBUG(3,("reduce_name: couldn't get realpath for %s\n", fname));
900                                         return map_nt_error_from_unix(errno);
901                                 }
902                                 tmp_fname = talloc_asprintf(ctx,
903                                                 "%s/%s",
904                                                 resolved_name,
905                                                 last_component);
906                                 if (!tmp_fname) {
907                                         return NT_STATUS_NO_MEMORY;
908                                 }
909 #ifdef REALPATH_TAKES_NULL
910                                 SAFE_FREE(resolved_name);
911                                 resolved_name = SMB_STRDUP(tmp_fname);
912                                 if (!resolved_name) {
913                                         DEBUG(0,("reduce_name: malloc fail for %s\n", tmp_fname));
914                                         return NT_STATUS_NO_MEMORY;
915                                 }
916 #else
917                                 safe_strcpy(resolved_name_buf, tmp_fname, PATH_MAX);
918                                 resolved_name = resolved_name_buf;
919 #endif
920                                 break;
921                         }
922                         default:
923                                 DEBUG(1,("reduce_name: couldn't get realpath for %s\n", fname));
924                                 return map_nt_error_from_unix(errno);
925                 }
926         }
927
928         DEBUG(10,("reduce_name realpath [%s] -> [%s]\n", fname, resolved_name));
929
930         if (*resolved_name != '/') {
931                 DEBUG(0,("reduce_name: realpath doesn't return absolute paths !\n"));
932                 if (free_resolved_name) {
933                         SAFE_FREE(resolved_name);
934                 }
935                 return NT_STATUS_OBJECT_NAME_INVALID;
936         }
937
938         /* Check for widelinks allowed. */
939         if (!lp_widelinks(SNUM(conn)) && (strncmp(conn->connectpath, resolved_name, con_path_len) != 0)) {
940                 DEBUG(2, ("reduce_name: Bad access attempt: %s is a symlink outside the share path", fname));
941                 if (free_resolved_name) {
942                         SAFE_FREE(resolved_name);
943                 }
944                 return NT_STATUS_ACCESS_DENIED;
945         }
946
947         /* Check if we are allowing users to follow symlinks */
948         /* Patch from David Clerc <David.Clerc@cui.unige.ch>
949                 University of Geneva */
950
951 #ifdef S_ISLNK
952         if (!lp_symlinks(SNUM(conn))) {
953                 SMB_STRUCT_STAT statbuf;
954                 if ( (SMB_VFS_LSTAT(conn,fname,&statbuf) != -1) &&
955                                 (S_ISLNK(statbuf.st_mode)) ) {
956                         if (free_resolved_name) {
957                                 SAFE_FREE(resolved_name);
958                         }
959                         DEBUG(3,("reduce_name: denied: file path name %s is a symlink\n",resolved_name));
960                         return NT_STATUS_ACCESS_DENIED;
961                 }
962         }
963 #endif
964
965         DEBUG(3,("reduce_name: %s reduced to %s\n", fname, resolved_name));
966         if (free_resolved_name) {
967                 SAFE_FREE(resolved_name);
968         }
969         return NT_STATUS_OK;
970 }