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/>.
21 #include "smbd/globals.h"
24 #define DBGC_CLASS DBGC_LOCKING
26 /****************************************************************************
27 This is the structure to queue to implement blocking locks.
28 notify. It consists of the requesting SMB and the expiry time.
29 *****************************************************************************/
31 typedef struct blocking_lock_record {
32 struct blocking_lock_record *next;
33 struct blocking_lock_record *prev;
35 struct timeval expire_time;
40 uint32_t blocking_pid; /* PID that blocks us. */
41 enum brl_flavour lock_flav;
42 enum brl_type lock_type;
43 struct smb_request *req;
44 } blocking_lock_record;
46 /****************************************************************************
47 Determine if this is a secondary element of a chained SMB.
48 **************************************************************************/
50 static bool in_chained_smb(void)
52 return (chain_size != 0);
55 static void received_unlock_msg(struct messaging_context *msg,
58 struct server_id server_id,
60 static void process_blocking_lock_queue(void);
62 static void brl_timeout_fn(struct event_context *event_ctx,
63 struct timed_event *te,
67 SMB_ASSERT(brl_timeout == te);
68 TALLOC_FREE(brl_timeout);
70 change_to_root_user(); /* TODO: Possibly run all timed events as
73 process_blocking_lock_queue();
76 /****************************************************************************
77 After a change to blocking_lock_queue, recalculate the timed_event for the
79 ****************************************************************************/
81 static bool recalc_brl_timeout(void)
83 blocking_lock_record *brl;
84 struct timeval next_timeout;
86 TALLOC_FREE(brl_timeout);
88 next_timeout = timeval_zero();
90 for (brl = blocking_lock_queue; brl; brl = brl->next) {
91 if (timeval_is_zero(&brl->expire_time)) {
93 * If we're blocked on pid 0xFFFFFFFF this is
94 * a POSIX lock, so calculate a timeout of
95 * 10 seconds into the future.
97 if (brl->blocking_pid == 0xFFFFFFFF) {
98 struct timeval psx_to = timeval_current_ofs(10, 0);
99 next_timeout = timeval_min(&next_timeout, &psx_to);
105 if (timeval_is_zero(&next_timeout)) {
106 next_timeout = brl->expire_time;
109 next_timeout = timeval_min(&next_timeout,
114 if (timeval_is_zero(&next_timeout)) {
118 if (!(brl_timeout = event_add_timed(smbd_event_context(), NULL,
120 brl_timeout_fn, NULL))) {
128 /****************************************************************************
129 Function to push a blocking lock request onto the lock queue.
130 ****************************************************************************/
132 bool push_blocking_lock_request( struct byte_range_lock *br_lck,
133 struct smb_request *req,
138 enum brl_type lock_type,
139 enum brl_flavour lock_flav,
142 uint32_t blocking_pid)
144 blocking_lock_record *blr;
147 if(in_chained_smb() ) {
148 DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
153 * Now queue an entry on the blocking lock queue. We setup
154 * the expiration time here.
157 blr = talloc(NULL, struct blocking_lock_record);
159 DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
167 if (lock_timeout == -1) {
168 blr->expire_time.tv_sec = 0;
169 blr->expire_time.tv_usec = 0; /* Never expire. */
171 blr->expire_time = timeval_current_ofs(lock_timeout/1000,
172 (lock_timeout % 1000) * 1000);
174 blr->lock_num = lock_num;
175 blr->lock_pid = lock_pid;
176 blr->blocking_pid = blocking_pid;
177 blr->lock_flav = lock_flav;
178 blr->lock_type = lock_type;
179 blr->offset = offset;
182 /* Add a pending lock record for this. */
183 status = brl_lock(smbd_messaging_context(), br_lck,
188 lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK,
190 lock_timeout ? True : False, /* blocking_lock. */
193 if (!NT_STATUS_IS_OK(status)) {
194 DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n"));
195 DLIST_REMOVE(blocking_lock_queue, blr);
200 blr->req = talloc_move(blr, &req);
202 DLIST_ADD_END(blocking_lock_queue, blr, blocking_lock_record *);
203 recalc_brl_timeout();
205 /* Ensure we'll receive messages when this is unlocked. */
206 if (!blocking_lock_unlock_state) {
207 messaging_register(smbd_messaging_context(), NULL,
208 MSG_SMB_UNLOCK, received_unlock_msg);
209 blocking_lock_unlock_state = true;
212 DEBUG(3,("push_blocking_lock_request: lock request blocked with "
213 "expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n",
214 (unsigned int)blr->expire_time.tv_sec,
215 (unsigned int)blr->expire_time.tv_usec, lock_timeout,
216 blr->fsp->fnum, blr->fsp->fsp_name ));
218 /* Push the MID of this packet on the signing queue. */
219 srv_defer_sign_response(blr->req->mid);
224 /****************************************************************************
225 Return a lockingX success SMB.
226 *****************************************************************************/
228 static void reply_lockingX_success(blocking_lock_record *blr)
230 reply_outbuf(blr->req, 2, 0);
233 * As this message is a lockingX call we must handle
234 * any following chained message correctly.
235 * This is normally handled in construct_reply(),
236 * but as that calls switch_message, we can't use
237 * that here and must set up the chain info manually.
240 chain_reply(blr->req);
242 if (!srv_send_smb(smbd_server_fd(), (char *)blr->req->outbuf,
243 IS_CONN_ENCRYPTED(blr->fsp->conn))) {
244 exit_server_cleanly("send_blocking_reply: srv_send_smb failed.");
247 TALLOC_FREE(blr->req->outbuf);
250 /****************************************************************************
251 Return a generic lock fail error blocking call.
252 *****************************************************************************/
254 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
256 /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
257 FILE_LOCK_CONFLICT! (tridge) */
258 if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
259 status = NT_STATUS_FILE_LOCK_CONFLICT;
262 if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
263 /* Store the last lock error. */
264 files_struct *fsp = blr->fsp;
267 fsp->last_lock_failure.context.smbpid = blr->lock_pid;
268 fsp->last_lock_failure.context.tid = fsp->conn->cnum;
269 fsp->last_lock_failure.context.pid = procid_self();
270 fsp->last_lock_failure.start = blr->offset;
271 fsp->last_lock_failure.size = blr->count;
272 fsp->last_lock_failure.fnum = fsp->fnum;
273 fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */
274 fsp->last_lock_failure.lock_flav = blr->lock_flav;
278 reply_nterror(blr->req, status);
279 if (!srv_send_smb(smbd_server_fd(), (char *)blr->req->outbuf,
280 blr->req->encrypted)) {
281 exit_server_cleanly("generic_blocking_lock_error: srv_send_smb failed.");
283 TALLOC_FREE(blr->req->outbuf);
286 /****************************************************************************
287 Return a lock fail error for a lockingX call. Undo all the locks we have
289 *****************************************************************************/
291 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
293 files_struct *fsp = blr->fsp;
294 uint16 num_ulocks = SVAL(blr->req->vwv+6, 0);
295 uint64_t count = (uint64_t)0, offset = (uint64_t) 0;
297 unsigned char locktype = CVAL(blr->req->vwv+3, 0);
298 bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
302 data = (uint8_t *)blr->req->buf
303 + ((large_file_format ? 20 : 10)*num_ulocks);
306 * Data now points at the beginning of the list
307 * of smb_lkrng structs.
311 * Ensure we don't do a remove on the lock that just failed,
312 * as under POSIX rules, if we have a lock already there, we
313 * will delete it (and we shouldn't) .....
316 for(i = blr->lock_num - 1; i >= 0; i--) {
319 lock_pid = get_lock_pid( data, i, large_file_format);
320 count = get_lock_count( data, i, large_file_format);
321 offset = get_lock_offset( data, i, large_file_format, &err);
324 * We know err cannot be set as if it was the lock
325 * request would never have been queued. JRA.
328 do_unlock(smbd_messaging_context(),
336 generic_blocking_lock_error(blr, status);
339 /****************************************************************************
340 Return a lock fail error.
341 *****************************************************************************/
343 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
345 switch(blr->req->cmd) {
347 reply_lockingX_error(blr, status);
351 reply_nterror(blr->req, status);
354 * construct_reply_common has done us the favor to pre-fill
355 * the command field with SMBtranss2 which is wrong :-)
357 SCVAL(blr->req->outbuf,smb_com,SMBtrans2);
359 if (!srv_send_smb(smbd_server_fd(),
360 (char *)blr->req->outbuf,
361 IS_CONN_ENCRYPTED(blr->fsp->conn))) {
362 exit_server_cleanly("blocking_lock_reply_error: "
363 "srv_send_smb failed.");
365 TALLOC_FREE(blr->req->outbuf);
368 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
369 exit_server("PANIC - unknown type on blocking lock queue");
373 /****************************************************************************
374 Attempt to finish off getting all pending blocking locks for a lockingX call.
375 Returns True if we want to be removed from the list.
376 *****************************************************************************/
378 static bool process_lockingX(blocking_lock_record *blr)
380 unsigned char locktype = CVAL(blr->req->vwv+3, 0);
381 files_struct *fsp = blr->fsp;
382 uint16 num_ulocks = SVAL(blr->req->vwv+6, 0);
383 uint16 num_locks = SVAL(blr->req->vwv+7, 0);
384 uint64_t count = (uint64_t)0, offset = (uint64_t)0;
386 bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
388 NTSTATUS status = NT_STATUS_OK;
390 data = (uint8_t *)blr->req->buf
391 + ((large_file_format ? 20 : 10)*num_ulocks);
394 * Data now points at the beginning of the list
395 * of smb_lkrng structs.
398 for(; blr->lock_num < num_locks; blr->lock_num++) {
399 struct byte_range_lock *br_lck = NULL;
402 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
403 count = get_lock_count( data, blr->lock_num, large_file_format);
404 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
407 * We know err cannot be set as if it was the lock
408 * request would never have been queued. JRA.
411 br_lck = do_lock(smbd_messaging_context(),
416 ((locktype & LOCKING_ANDX_SHARED_LOCK) ?
417 READ_LOCK : WRITE_LOCK),
425 if (NT_STATUS_IS_ERR(status)) {
430 if(blr->lock_num == num_locks) {
432 * Success - we got all the locks.
435 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
436 fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
438 reply_lockingX_success(blr);
442 if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
443 !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
445 * We have other than a "can't get lock"
446 * error. Free any locks we had and return an error.
447 * Return True so we get dequeued.
449 blocking_lock_reply_error(blr, status);
454 * Still can't get all the locks - keep waiting.
457 DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
459 blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
464 /****************************************************************************
465 Attempt to get the posix lock request from a SMBtrans2 call.
466 Returns True if we want to be removed from the list.
467 *****************************************************************************/
469 static bool process_trans2(blocking_lock_record *blr)
473 struct byte_range_lock *br_lck = do_lock(smbd_messaging_context(),
485 if (!NT_STATUS_IS_OK(status)) {
486 if (ERROR_WAS_LOCK_DENIED(status)) {
487 /* Still can't get the lock, just keep waiting. */
491 * We have other than a "can't get lock"
492 * error. Send an error and return True so we get dequeued.
494 blocking_lock_reply_error(blr, status);
498 /* We finally got the lock, return success. */
501 /* Fake up max_data_bytes here - we know it fits. */
502 send_trans2_replies(blr->fsp->conn, blr->req, params, 2, NULL, 0, 0xffff);
507 /****************************************************************************
508 Process a blocking lock SMB.
509 Returns True if we want to be removed from the list.
510 *****************************************************************************/
512 static bool blocking_lock_record_process(blocking_lock_record *blr)
514 switch(blr->req->cmd) {
516 return process_lockingX(blr);
519 return process_trans2(blr);
521 DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
522 exit_server("PANIC - unknown type on blocking lock queue");
524 return False; /* Keep compiler happy. */
527 /****************************************************************************
528 Cancel entries by fnum from the blocking lock pending queue.
529 *****************************************************************************/
531 void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck)
533 blocking_lock_record *blr, *next = NULL;
535 for(blr = blocking_lock_queue; blr; blr = next) {
536 unsigned char locktype = 0;
539 if (blr->fsp->fnum != fsp->fnum) {
543 if (blr->req->cmd == SMBlockingX) {
544 locktype = CVAL(blr->req->vwv+3, 0);
547 DEBUG(10, ("remove_pending_lock_requests_by_fid - removing "
548 "request type %d for file %s fnum = %d\n",
549 blr->req->cmd, fsp->fsp_name, fsp->fnum));
551 brl_lock_cancel(br_lck,
558 blocking_lock_cancel(fsp,
564 NT_STATUS_RANGE_NOT_LOCKED);
566 /* We're closing the file fsp here, so ensure
567 * we don't have a dangling pointer. */
572 /****************************************************************************
573 Delete entries by mid from the blocking lock pending queue. Always send reply.
574 *****************************************************************************/
576 void remove_pending_lock_requests_by_mid(int mid)
578 blocking_lock_record *blr, *next = NULL;
580 for(blr = blocking_lock_queue; blr; blr = next) {
582 struct byte_range_lock *br_lck;
586 if (blr->req->mid != mid) {
591 br_lck = brl_get_locks(talloc_tos(), fsp);
594 DEBUG(10, ("remove_pending_lock_requests_by_mid - "
595 "removing request type %d for file %s fnum "
596 "= %d\n", blr->req->cmd, fsp->fsp_name,
599 brl_lock_cancel(br_lck,
608 blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
609 DLIST_REMOVE(blocking_lock_queue, blr);
614 /****************************************************************************
615 Is this mid a blocking lock request on the queue ?
616 *****************************************************************************/
618 bool blocking_lock_was_deferred(int mid)
620 blocking_lock_record *blr, *next = NULL;
622 for(blr = blocking_lock_queue; blr; blr = next) {
624 if(blr->req->mid == mid) {
631 /****************************************************************************
632 Set a flag as an unlock request affects one of our pending locks.
633 *****************************************************************************/
635 static void received_unlock_msg(struct messaging_context *msg,
638 struct server_id server_id,
641 DEBUG(10,("received_unlock_msg\n"));
642 process_blocking_lock_queue();
645 /****************************************************************************
646 Process the blocking lock queue. Note that this is only called as root.
647 *****************************************************************************/
649 static void process_blocking_lock_queue(void)
651 struct timeval tv_curr = timeval_current();
652 blocking_lock_record *blr, *next = NULL;
653 bool recalc_timeout = False;
656 * Go through the queue and see if we can get any of the locks.
659 for (blr = blocking_lock_queue; blr; blr = next) {
664 * Go through the remaining locks and try and obtain them.
665 * The call returns True if all locks were obtained successfully
666 * and False if we still need to wait.
669 if(blocking_lock_record_process(blr)) {
670 struct byte_range_lock *br_lck = brl_get_locks(
671 talloc_tos(), blr->fsp);
674 brl_lock_cancel(br_lck,
683 DLIST_REMOVE(blocking_lock_queue, blr);
685 recalc_timeout = True;
690 * We couldn't get the locks for this record on the list.
691 * If the time has expired, return a lock error.
694 if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) {
695 struct byte_range_lock *br_lck = brl_get_locks(
696 talloc_tos(), blr->fsp);
699 * Lock expired - throw away all previously
700 * obtained locks and return lock error.
704 DEBUG(5,("process_blocking_lock_queue: "
705 "pending lock fnum = %d for file %s "
706 "timed out.\n", blr->fsp->fnum,
707 blr->fsp->fsp_name ));
709 brl_lock_cancel(br_lck,
718 blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
719 DLIST_REMOVE(blocking_lock_queue, blr);
721 recalc_timeout = True;
725 if (recalc_timeout) {
726 recalc_brl_timeout();
730 /****************************************************************************
731 Handle a cancel message. Lock already moved onto the cancel queue.
732 *****************************************************************************/
734 #define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS))
736 static void process_blocking_lock_cancel_message(struct messaging_context *ctx,
739 struct server_id server_id,
743 const char *msg = (const char *)data->data;
744 blocking_lock_record *blr;
746 if (data->data == NULL) {
747 smb_panic("process_blocking_lock_cancel_message: null msg");
750 if (data->length != MSG_BLOCKING_LOCK_CANCEL_SIZE) {
751 DEBUG(0, ("process_blocking_lock_cancel_message: "
752 "Got invalid msg len %d\n", (int)data->length));
753 smb_panic("process_blocking_lock_cancel_message: bad msg");
756 memcpy(&blr, msg, sizeof(blr));
757 memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS));
759 DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n",
762 blocking_lock_reply_error(blr, err);
763 DLIST_REMOVE(blocking_lock_cancelled_queue, blr);
767 /****************************************************************************
768 Send ourselves a blocking lock cancelled message. Handled asynchronously above.
769 *****************************************************************************/
771 bool blocking_lock_cancel(files_struct *fsp,
775 enum brl_flavour lock_flav,
776 unsigned char locktype,
779 char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE];
780 blocking_lock_record *blr;
782 if (!blocking_lock_cancel_state) {
783 /* Register our message. */
784 messaging_register(smbd_messaging_context(), NULL,
785 MSG_SMB_BLOCKING_LOCK_CANCEL,
786 process_blocking_lock_cancel_message);
788 blocking_lock_cancel_state = True;
791 for (blr = blocking_lock_queue; blr; blr = blr->next) {
792 if (fsp == blr->fsp &&
793 lock_pid == blr->lock_pid &&
794 offset == blr->offset &&
795 count == blr->count &&
796 lock_flav == blr->lock_flav) {
805 /* Check the flags are right. */
806 if (blr->req->cmd == SMBlockingX &&
807 (locktype & LOCKING_ANDX_LARGE_FILES) !=
808 (CVAL(blr->req->vwv+3, 0) & LOCKING_ANDX_LARGE_FILES)) {
812 /* Move to cancelled queue. */
813 DLIST_REMOVE(blocking_lock_queue, blr);
814 DLIST_ADD(blocking_lock_cancelled_queue, blr);
816 /* Create the message. */
817 memcpy(msg, &blr, sizeof(blr));
818 memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));
820 messaging_send_buf(smbd_messaging_context(), procid_self(),
821 MSG_SMB_BLOCKING_LOCK_CANCEL,
822 (uint8 *)&msg, sizeof(msg));