2 Unix SMB/CIFS implementation.
3 Blocking Locking functions
4 Copyright (C) Jeremy Allison 1998-2003
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 #define DBGC_CLASS DBGC_LOCKING
24 /****************************************************************************
25 This is the structure to queue to implement blocking locks.
26 notify. It consists of the requesting SMB and the expiry time.
27 *****************************************************************************/
29 typedef struct blocking_lock_record {
30 struct blocking_lock_record *next;
31 struct blocking_lock_record *prev;
34 struct timeval expire_time;
39 uint32_t blocking_pid; /* PID that blocks us. */
40 enum brl_flavour lock_flav;
41 enum brl_type lock_type;
45 } blocking_lock_record;
47 /* dlink list we store pending lock records on. */
48 static blocking_lock_record *blocking_lock_queue;
50 /* dlink list we move cancelled lock records onto. */
51 static blocking_lock_record *blocking_lock_cancelled_queue;
53 /* The event that makes us process our blocking lock queue */
54 static struct timed_event *brl_timeout;
56 /****************************************************************************
57 Determine if this is a secondary element of a chained SMB.
58 **************************************************************************/
60 static bool in_chained_smb(void)
62 return (chain_size != 0);
65 static void received_unlock_msg(struct messaging_context *msg,
68 struct server_id server_id,
70 static void process_blocking_lock_queue(void);
72 static void brl_timeout_fn(struct event_context *event_ctx,
73 struct timed_event *te,
74 const struct timeval *now,
77 SMB_ASSERT(brl_timeout == te);
78 TALLOC_FREE(brl_timeout);
80 change_to_root_user(); /* TODO: Possibly run all timed events as
83 process_blocking_lock_queue();
86 /****************************************************************************
87 After a change to blocking_lock_queue, recalculate the timed_event for the
89 ****************************************************************************/
91 static bool recalc_brl_timeout(void)
93 blocking_lock_record *brl;
94 struct timeval next_timeout;
96 TALLOC_FREE(brl_timeout);
98 next_timeout = timeval_zero();
100 for (brl = blocking_lock_queue; brl; brl = brl->next) {
101 if (timeval_is_zero(&brl->expire_time)) {
103 * If we're blocked on pid 0xFFFFFFFF this is
104 * a POSIX lock, so calculate a timeout of
105 * 10 seconds into the future.
107 if (brl->blocking_pid == 0xFFFFFFFF) {
108 struct timeval psx_to = timeval_current_ofs(10, 0);
109 next_timeout = timeval_min(&next_timeout, &psx_to);
115 if (timeval_is_zero(&next_timeout)) {
116 next_timeout = brl->expire_time;
119 next_timeout = timeval_min(&next_timeout,
124 if (timeval_is_zero(&next_timeout)) {
128 if (!(brl_timeout = event_add_timed(smbd_event_context(), NULL,
129 next_timeout, "brl_timeout",
130 brl_timeout_fn, NULL))) {
138 /****************************************************************************
139 Function to push a blocking lock request onto the lock queue.
140 ****************************************************************************/
142 bool push_blocking_lock_request( struct byte_range_lock *br_lck,
143 const struct smb_request *req,
148 enum brl_type lock_type,
149 enum brl_flavour lock_flav,
152 uint32_t blocking_pid)
154 static bool set_lock_msg;
155 size_t length = smb_len(req->inbuf)+4;
156 blocking_lock_record *blr;
159 if(in_chained_smb() ) {
160 DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
165 * Now queue an entry on the blocking lock queue. We setup
166 * the expiration time here.
169 blr = talloc(NULL, struct blocking_lock_record);
171 DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
178 blr->inbuf = TALLOC_ARRAY(blr, char, length);
179 if (blr->inbuf == NULL) {
180 DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
185 blr->com_type = req->cmd;
187 if (lock_timeout == -1) {
188 blr->expire_time.tv_sec = 0;
189 blr->expire_time.tv_usec = 0; /* Never expire. */
191 blr->expire_time = timeval_current_ofs(lock_timeout/1000,
192 (lock_timeout % 1000) * 1000);
194 blr->lock_num = lock_num;
195 blr->lock_pid = lock_pid;
196 blr->blocking_pid = blocking_pid;
197 blr->lock_flav = lock_flav;
198 blr->lock_type = lock_type;
199 blr->offset = offset;
201 memcpy(blr->inbuf, req->inbuf, length);
202 blr->length = length;
203 blr->encrypted = req->encrypted;
205 /* Add a pending lock record for this. */
206 status = brl_lock(smbd_messaging_context(), br_lck,
211 lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK,
213 lock_timeout ? True : False, /* blocking_lock. */
216 if (!NT_STATUS_IS_OK(status)) {
217 DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n"));
218 DLIST_REMOVE(blocking_lock_queue, blr);
223 DLIST_ADD_END(blocking_lock_queue, blr, blocking_lock_record *);
224 recalc_brl_timeout();
226 /* Ensure we'll receive messages when this is unlocked. */
228 messaging_register(smbd_messaging_context(), NULL,
229 MSG_SMB_UNLOCK, received_unlock_msg);
233 DEBUG(3,("push_blocking_lock_request: lock request length=%u blocked with "
234 "expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n",
235 (unsigned int)length, (unsigned int)blr->expire_time.tv_sec,
236 (unsigned int)blr->expire_time.tv_usec, lock_timeout,
237 blr->fsp->fnum, blr->fsp->fsp_name ));
239 /* Push the MID of this packet on the signing queue. */
240 srv_defer_sign_response(SVAL(req->inbuf,smb_mid));
245 /****************************************************************************
246 Return a lockingX success SMB.
247 *****************************************************************************/
249 static void reply_lockingX_success(blocking_lock_record *blr)
251 struct smb_request *req;
253 if (!(req = talloc(talloc_tos(), struct smb_request))) {
254 smb_panic("Could not allocate smb_request");
257 init_smb_request(req, (uint8 *)blr->inbuf, 0, blr->encrypted);
258 req->inbuf = (uint8_t *)(blr->inbuf);
259 reply_outbuf(req, 2, 0);
262 * As this message is a lockingX call we must handle
263 * any following chained message correctly.
264 * This is normally handled in construct_reply(),
265 * but as that calls switch_message, we can't use
266 * that here and must set up the chain info manually.
271 if (!srv_send_smb(smbd_server_fd(),
273 IS_CONN_ENCRYPTED(blr->fsp->conn))) {
274 exit_server_cleanly("send_blocking_reply: srv_send_smb failed.");
278 /****************************************************************************
279 Return a generic lock fail error blocking call.
280 *****************************************************************************/
282 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
284 char outbuf[smb_size];
285 char *inbuf = blr->inbuf;
287 construct_reply_common(inbuf, outbuf);
289 /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
290 FILE_LOCK_CONFLICT! (tridge) */
291 if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
292 status = NT_STATUS_FILE_LOCK_CONFLICT;
295 if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
296 /* Store the last lock error. */
297 files_struct *fsp = blr->fsp;
300 fsp->last_lock_failure.context.smbpid = blr->lock_pid;
301 fsp->last_lock_failure.context.tid = fsp->conn->cnum;
302 fsp->last_lock_failure.context.pid = procid_self();
303 fsp->last_lock_failure.start = blr->offset;
304 fsp->last_lock_failure.size = blr->count;
305 fsp->last_lock_failure.fnum = fsp->fnum;
306 fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */
307 fsp->last_lock_failure.lock_flav = blr->lock_flav;
312 if (!srv_send_smb(smbd_server_fd(),outbuf, blr->encrypted)) {
313 exit_server_cleanly("generic_blocking_lock_error: srv_send_smb failed.");
317 /****************************************************************************
318 Return a lock fail error for a lockingX call. Undo all the locks we have
320 *****************************************************************************/
322 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
324 char *inbuf = blr->inbuf;
325 files_struct *fsp = blr->fsp;
326 uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
327 uint64_t count = (uint64_t)0, offset = (uint64_t) 0;
329 unsigned char locktype = CVAL(inbuf,smb_vwv3);
330 bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
334 data = (uint8_t *)smb_buf(inbuf)
335 + ((large_file_format ? 20 : 10)*num_ulocks);
338 * Data now points at the beginning of the list
339 * of smb_lkrng structs.
343 * Ensure we don't do a remove on the lock that just failed,
344 * as under POSIX rules, if we have a lock already there, we
345 * will delete it (and we shouldn't) .....
348 for(i = blr->lock_num - 1; i >= 0; i--) {
351 lock_pid = get_lock_pid( data, i, large_file_format);
352 count = get_lock_count( data, i, large_file_format);
353 offset = get_lock_offset( data, i, large_file_format, &err);
356 * We know err cannot be set as if it was the lock
357 * request would never have been queued. JRA.
360 do_unlock(smbd_messaging_context(),
368 generic_blocking_lock_error(blr, status);
371 /****************************************************************************
372 Return a lock fail error.
373 *****************************************************************************/
375 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
377 switch(blr->com_type) {
379 reply_lockingX_error(blr, status);
384 char outbuf[smb_size];
385 char *inbuf = blr->inbuf;
386 construct_reply_common(inbuf, outbuf);
387 /* construct_reply_common has done us the favor to pre-fill the
388 * command field with SMBtranss2 which is wrong :-)
390 SCVAL(outbuf,smb_com,SMBtrans2);
392 if (!srv_send_smb(smbd_server_fd(),
394 IS_CONN_ENCRYPTED(blr->fsp->conn))) {
395 exit_server_cleanly("blocking_lock_reply_error: srv_send_smb failed.");
400 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
401 exit_server("PANIC - unknown type on blocking lock queue");
405 /****************************************************************************
406 Attempt to finish off getting all pending blocking locks for a lockingX call.
407 Returns True if we want to be removed from the list.
408 *****************************************************************************/
410 static bool process_lockingX(blocking_lock_record *blr)
412 char *inbuf = blr->inbuf;
413 unsigned char locktype = CVAL(inbuf,smb_vwv3);
414 files_struct *fsp = blr->fsp;
415 uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
416 uint16 num_locks = SVAL(inbuf,smb_vwv7);
417 uint64_t count = (uint64_t)0, offset = (uint64_t)0;
419 bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
421 NTSTATUS status = NT_STATUS_OK;
423 data = (uint8_t *)smb_buf(inbuf)
424 + ((large_file_format ? 20 : 10)*num_ulocks);
427 * Data now points at the beginning of the list
428 * of smb_lkrng structs.
431 for(; blr->lock_num < num_locks; blr->lock_num++) {
432 struct byte_range_lock *br_lck = NULL;
435 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
436 count = get_lock_count( data, blr->lock_num, large_file_format);
437 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
440 * We know err cannot be set as if it was the lock
441 * request would never have been queued. JRA.
444 br_lck = do_lock(smbd_messaging_context(),
449 ((locktype & LOCKING_ANDX_SHARED_LOCK) ?
450 READ_LOCK : WRITE_LOCK),
458 if (NT_STATUS_IS_ERR(status)) {
463 if(blr->lock_num == num_locks) {
465 * Success - we got all the locks.
468 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
469 fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
471 reply_lockingX_success(blr);
473 } else if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
474 !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
476 * We have other than a "can't get lock"
477 * error. Free any locks we had and return an error.
478 * Return True so we get dequeued.
481 blocking_lock_reply_error(blr, status);
486 * Still can't get all the locks - keep waiting.
489 DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
491 blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
496 /****************************************************************************
497 Attempt to get the posix lock request from a SMBtrans2 call.
498 Returns True if we want to be removed from the list.
499 *****************************************************************************/
501 static bool process_trans2(blocking_lock_record *blr)
503 struct smb_request *req;
506 struct byte_range_lock *br_lck = do_lock(smbd_messaging_context(),
518 if (!NT_STATUS_IS_OK(status)) {
519 if (ERROR_WAS_LOCK_DENIED(status)) {
520 /* Still can't get the lock, just keep waiting. */
524 * We have other than a "can't get lock"
525 * error. Send an error and return True so we get dequeued.
527 blocking_lock_reply_error(blr, status);
531 /* We finally got the lock, return success. */
533 if (!(req = talloc(talloc_tos(), struct smb_request))) {
534 blocking_lock_reply_error(blr, NT_STATUS_NO_MEMORY);
538 init_smb_request(req, (uint8 *)blr->inbuf, 0, blr->encrypted);
539 req->inbuf = (uint8_t *)(blr->inbuf);
541 SCVAL(req->inbuf, smb_com, SMBtrans2);
543 /* Fake up max_data_bytes here - we know it fits. */
544 send_trans2_replies(blr->fsp->conn, req, params, 2, NULL, 0, 0xffff);
549 /****************************************************************************
550 Process a blocking lock SMB.
551 Returns True if we want to be removed from the list.
552 *****************************************************************************/
554 static bool blocking_lock_record_process(blocking_lock_record *blr)
556 switch(blr->com_type) {
558 return process_lockingX(blr);
561 return process_trans2(blr);
563 DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
564 exit_server("PANIC - unknown type on blocking lock queue");
566 return False; /* Keep compiler happy. */
569 /****************************************************************************
570 Cancel entries by fnum from the blocking lock pending queue.
571 *****************************************************************************/
573 void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck)
575 blocking_lock_record *blr, *next = NULL;
577 for(blr = blocking_lock_queue; blr; blr = next) {
578 unsigned char locktype = 0;
581 if (blr->fsp->fnum != fsp->fnum) {
585 if (blr->com_type == SMBlockingX) {
586 locktype = CVAL(blr->inbuf,smb_vwv3);
590 DEBUG(10, ("remove_pending_lock_requests_by_fid - "
591 "removing request type %d for file %s fnum "
592 "= %d\n", blr->com_type, fsp->fsp_name,
595 brl_lock_cancel(br_lck,
602 blocking_lock_cancel(fsp,
608 NT_STATUS_RANGE_NOT_LOCKED);
610 /* We're closing the file fsp here, so ensure
611 * we don't have a dangling pointer. */
616 /****************************************************************************
617 Delete entries by mid from the blocking lock pending queue. Always send reply.
618 *****************************************************************************/
620 void remove_pending_lock_requests_by_mid(int mid)
622 blocking_lock_record *blr, *next = NULL;
624 for(blr = blocking_lock_queue; blr; blr = next) {
626 if(SVAL(blr->inbuf,smb_mid) == mid) {
627 files_struct *fsp = blr->fsp;
628 struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
631 DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
632 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
634 brl_lock_cancel(br_lck,
643 blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
644 DLIST_REMOVE(blocking_lock_queue, blr);
650 /****************************************************************************
651 Is this mid a blocking lock request on the queue ?
652 *****************************************************************************/
654 bool blocking_lock_was_deferred(int mid)
656 blocking_lock_record *blr, *next = NULL;
658 for(blr = blocking_lock_queue; blr; blr = next) {
660 if(SVAL(blr->inbuf,smb_mid) == mid) {
667 /****************************************************************************
668 Set a flag as an unlock request affects one of our pending locks.
669 *****************************************************************************/
671 static void received_unlock_msg(struct messaging_context *msg,
674 struct server_id server_id,
677 DEBUG(10,("received_unlock_msg\n"));
678 process_blocking_lock_queue();
681 /****************************************************************************
682 Process the blocking lock queue. Note that this is only called as root.
683 *****************************************************************************/
685 static void process_blocking_lock_queue(void)
687 struct timeval tv_curr = timeval_current();
688 blocking_lock_record *blr, *next = NULL;
689 bool recalc_timeout = False;
692 * Go through the queue and see if we can get any of the locks.
695 for (blr = blocking_lock_queue; blr; blr = next) {
696 connection_struct *conn = NULL;
698 files_struct *fsp = NULL;
703 * Ensure we don't have any old chain_fsp values
709 conn = conn_find(SVAL(blr->inbuf,smb_tid));
710 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
711 SVAL(blr->inbuf,smb_uid);
713 DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
714 fsp->fnum, fsp->fsp_name ));
716 if(!change_to_user(conn,vuid)) {
717 struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
720 * Remove the entry and return an error to the client.
724 brl_lock_cancel(br_lck,
733 DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
735 blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
736 DLIST_REMOVE(blocking_lock_queue, blr);
738 recalc_timeout = True;
742 if(!set_current_service(conn,SVAL(blr->inbuf,smb_flg),True)) {
743 struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
746 * Remove the entry and return an error to the client.
750 brl_lock_cancel(br_lck,
759 DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
760 blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
761 DLIST_REMOVE(blocking_lock_queue, blr);
763 recalc_timeout = True;
764 change_to_root_user();
769 * Go through the remaining locks and try and obtain them.
770 * The call returns True if all locks were obtained successfully
771 * and False if we still need to wait.
774 if(blocking_lock_record_process(blr)) {
775 struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
778 brl_lock_cancel(br_lck,
787 DLIST_REMOVE(blocking_lock_queue, blr);
789 recalc_timeout = True;
790 change_to_root_user();
794 change_to_root_user();
797 * We couldn't get the locks for this record on the list.
798 * If the time has expired, return a lock error.
801 if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) {
802 struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
805 * Lock expired - throw away all previously
806 * obtained locks and return lock error.
810 DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
811 fsp->fnum, fsp->fsp_name ));
813 brl_lock_cancel(br_lck,
822 blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
823 DLIST_REMOVE(blocking_lock_queue, blr);
825 recalc_timeout = True;
829 if (recalc_timeout) {
830 recalc_brl_timeout();
834 /****************************************************************************
835 Handle a cancel message. Lock already moved onto the cancel queue.
836 *****************************************************************************/
838 #define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS))
840 static void process_blocking_lock_cancel_message(struct messaging_context *ctx,
843 struct server_id server_id,
847 const char *msg = (const char *)data->data;
848 blocking_lock_record *blr;
850 if (data->data == NULL) {
851 smb_panic("process_blocking_lock_cancel_message: null msg");
854 if (data->length != MSG_BLOCKING_LOCK_CANCEL_SIZE) {
855 DEBUG(0, ("process_blocking_lock_cancel_message: "
856 "Got invalid msg len %d\n", (int)data->length));
857 smb_panic("process_blocking_lock_cancel_message: bad msg");
860 memcpy(&blr, msg, sizeof(blr));
861 memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS));
863 DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n",
866 blocking_lock_reply_error(blr, err);
867 DLIST_REMOVE(blocking_lock_cancelled_queue, blr);
871 /****************************************************************************
872 Send ourselves a blocking lock cancelled message. Handled asynchronously above.
873 *****************************************************************************/
875 bool blocking_lock_cancel(files_struct *fsp,
879 enum brl_flavour lock_flav,
880 unsigned char locktype,
883 static bool initialized;
884 char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE];
885 blocking_lock_record *blr;
888 /* Register our message. */
889 messaging_register(smbd_messaging_context(), NULL,
890 MSG_SMB_BLOCKING_LOCK_CANCEL,
891 process_blocking_lock_cancel_message);
896 for (blr = blocking_lock_queue; blr; blr = blr->next) {
897 if (fsp == blr->fsp &&
898 lock_pid == blr->lock_pid &&
899 offset == blr->offset &&
900 count == blr->count &&
901 lock_flav == blr->lock_flav) {
910 /* Check the flags are right. */
911 if (blr->com_type == SMBlockingX &&
912 (locktype & LOCKING_ANDX_LARGE_FILES) !=
913 (CVAL(blr->inbuf,smb_vwv3) & LOCKING_ANDX_LARGE_FILES)) {
917 /* Move to cancelled queue. */
918 DLIST_REMOVE(blocking_lock_queue, blr);
919 DLIST_ADD(blocking_lock_cancelled_queue, blr);
921 /* Create the message. */
922 memcpy(msg, &blr, sizeof(blr));
923 memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));
925 messaging_send_buf(smbd_messaging_context(), procid_self(),
926 MSG_SMB_BLOCKING_LOCK_CANCEL,
927 (uint8 *)&msg, sizeof(msg));