/* Unix SMB/CIFS implementation. Blocking Locking functions Copyright (C) Jeremy Allison 1998-2003 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "includes.h" #include "smbd/globals.h" #undef DBGC_CLASS #define DBGC_CLASS DBGC_LOCKING /**************************************************************************** This is the structure to queue to implement blocking locks. notify. It consists of the requesting SMB and the expiry time. *****************************************************************************/ typedef struct blocking_lock_record { struct blocking_lock_record *next; struct blocking_lock_record *prev; files_struct *fsp; struct timeval expire_time; int lock_num; uint64_t offset; uint64_t count; uint32_t lock_pid; uint32_t blocking_pid; /* PID that blocks us. */ enum brl_flavour lock_flav; enum brl_type lock_type; struct smb_request *req; } blocking_lock_record; /**************************************************************************** Determine if this is a secondary element of a chained SMB. **************************************************************************/ static bool in_chained_smb(void) { return (chain_size != 0); } static void received_unlock_msg(struct messaging_context *msg, void *private_data, uint32_t msg_type, struct server_id server_id, DATA_BLOB *data); static void process_blocking_lock_queue(void); static void brl_timeout_fn(struct event_context *event_ctx, struct timed_event *te, struct timeval now, void *private_data) { SMB_ASSERT(brl_timeout == te); TALLOC_FREE(brl_timeout); change_to_root_user(); /* TODO: Possibly run all timed events as * root */ process_blocking_lock_queue(); } /**************************************************************************** After a change to blocking_lock_queue, recalculate the timed_event for the next processing. ****************************************************************************/ static bool recalc_brl_timeout(void) { blocking_lock_record *brl; struct timeval next_timeout; TALLOC_FREE(brl_timeout); next_timeout = timeval_zero(); for (brl = blocking_lock_queue; brl; brl = brl->next) { if (timeval_is_zero(&brl->expire_time)) { /* * If we're blocked on pid 0xFFFFFFFF this is * a POSIX lock, so calculate a timeout of * 10 seconds into the future. */ if (brl->blocking_pid == 0xFFFFFFFF) { struct timeval psx_to = timeval_current_ofs(10, 0); next_timeout = timeval_min(&next_timeout, &psx_to); } continue; } if (timeval_is_zero(&next_timeout)) { next_timeout = brl->expire_time; } else { next_timeout = timeval_min(&next_timeout, &brl->expire_time); } } if (timeval_is_zero(&next_timeout)) { return True; } if (!(brl_timeout = event_add_timed(smbd_event_context(), NULL, next_timeout, brl_timeout_fn, NULL))) { return False; } return True; } /**************************************************************************** Function to push a blocking lock request onto the lock queue. ****************************************************************************/ bool push_blocking_lock_request( struct byte_range_lock *br_lck, struct smb_request *req, files_struct *fsp, int lock_timeout, int lock_num, uint32_t lock_pid, enum brl_type lock_type, enum brl_flavour lock_flav, uint64_t offset, uint64_t count, uint32_t blocking_pid) { blocking_lock_record *blr; NTSTATUS status; if(in_chained_smb() ) { DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n")); return False; } /* * Now queue an entry on the blocking lock queue. We setup * the expiration time here. */ blr = talloc(NULL, struct blocking_lock_record); if (blr == NULL) { DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" )); return False; } blr->next = NULL; blr->prev = NULL; blr->fsp = fsp; if (lock_timeout == -1) { blr->expire_time.tv_sec = 0; blr->expire_time.tv_usec = 0; /* Never expire. */ } else { blr->expire_time = timeval_current_ofs(lock_timeout/1000, (lock_timeout % 1000) * 1000); } blr->lock_num = lock_num; blr->lock_pid = lock_pid; blr->blocking_pid = blocking_pid; blr->lock_flav = lock_flav; blr->lock_type = lock_type; blr->offset = offset; blr->count = count; /* Add a pending lock record for this. */ status = brl_lock(smbd_messaging_context(), br_lck, lock_pid, procid_self(), offset, count, lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK, blr->lock_flav, lock_timeout ? True : False, /* blocking_lock. */ NULL); if (!NT_STATUS_IS_OK(status)) { DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n")); DLIST_REMOVE(blocking_lock_queue, blr); TALLOC_FREE(blr); return False; } blr->req = talloc_move(blr, &req); DLIST_ADD_END(blocking_lock_queue, blr, blocking_lock_record *); recalc_brl_timeout(); /* Ensure we'll receive messages when this is unlocked. */ if (!blocking_lock_unlock_state) { messaging_register(smbd_messaging_context(), NULL, MSG_SMB_UNLOCK, received_unlock_msg); blocking_lock_unlock_state = true; } DEBUG(3,("push_blocking_lock_request: lock request blocked with " "expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n", (unsigned int)blr->expire_time.tv_sec, (unsigned int)blr->expire_time.tv_usec, lock_timeout, blr->fsp->fnum, blr->fsp->fsp_name )); /* Push the MID of this packet on the signing queue. */ srv_defer_sign_response(blr->req->mid); return True; } /**************************************************************************** Return a lockingX success SMB. *****************************************************************************/ static void reply_lockingX_success(blocking_lock_record *blr) { reply_outbuf(blr->req, 2, 0); /* * As this message is a lockingX call we must handle * any following chained message correctly. * This is normally handled in construct_reply(), * but as that calls switch_message, we can't use * that here and must set up the chain info manually. */ chain_reply(blr->req); TALLOC_FREE(blr->req->outbuf); } /**************************************************************************** Return a generic lock fail error blocking call. *****************************************************************************/ static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status) { /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to FILE_LOCK_CONFLICT! (tridge) */ if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) { status = NT_STATUS_FILE_LOCK_CONFLICT; } if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) { /* Store the last lock error. */ files_struct *fsp = blr->fsp; if (fsp) { fsp->last_lock_failure.context.smbpid = blr->lock_pid; fsp->last_lock_failure.context.tid = fsp->conn->cnum; fsp->last_lock_failure.context.pid = procid_self(); fsp->last_lock_failure.start = blr->offset; fsp->last_lock_failure.size = blr->count; fsp->last_lock_failure.fnum = fsp->fnum; fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */ fsp->last_lock_failure.lock_flav = blr->lock_flav; } } reply_nterror(blr->req, status); if (!srv_send_smb(smbd_server_fd(), (char *)blr->req->outbuf, blr->req->encrypted)) { exit_server_cleanly("generic_blocking_lock_error: srv_send_smb failed."); } TALLOC_FREE(blr->req->outbuf); } /**************************************************************************** Return a lock fail error for a lockingX call. Undo all the locks we have obtained first. *****************************************************************************/ static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status) { files_struct *fsp = blr->fsp; uint16 num_ulocks = SVAL(blr->req->vwv+6, 0); uint64_t count = (uint64_t)0, offset = (uint64_t) 0; uint32 lock_pid; unsigned char locktype = CVAL(blr->req->vwv+3, 0); bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES); uint8_t *data; int i; data = (uint8_t *)blr->req->buf + ((large_file_format ? 20 : 10)*num_ulocks); /* * Data now points at the beginning of the list * of smb_lkrng structs. */ /* * Ensure we don't do a remove on the lock that just failed, * as under POSIX rules, if we have a lock already there, we * will delete it (and we shouldn't) ..... */ for(i = blr->lock_num - 1; i >= 0; i--) { bool err; lock_pid = get_lock_pid( data, i, large_file_format); count = get_lock_count( data, i, large_file_format); offset = get_lock_offset( data, i, large_file_format, &err); /* * We know err cannot be set as if it was the lock * request would never have been queued. JRA. */ do_unlock(smbd_messaging_context(), fsp, lock_pid, count, offset, WINDOWS_LOCK); } generic_blocking_lock_error(blr, status); } /**************************************************************************** Return a lock fail error. *****************************************************************************/ static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status) { switch(blr->req->cmd) { case SMBlockingX: reply_lockingX_error(blr, status); break; case SMBtrans2: case SMBtranss2: reply_nterror(blr->req, status); /* * construct_reply_common has done us the favor to pre-fill * the command field with SMBtranss2 which is wrong :-) */ SCVAL(blr->req->outbuf,smb_com,SMBtrans2); if (!srv_send_smb(smbd_server_fd(), (char *)blr->req->outbuf, IS_CONN_ENCRYPTED(blr->fsp->conn))) { exit_server_cleanly("blocking_lock_reply_error: " "srv_send_smb failed."); } TALLOC_FREE(blr->req->outbuf); break; default: DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n")); exit_server("PANIC - unknown type on blocking lock queue"); } } /**************************************************************************** Attempt to finish off getting all pending blocking locks for a lockingX call. Returns True if we want to be removed from the list. *****************************************************************************/ static bool process_lockingX(blocking_lock_record *blr) { unsigned char locktype = CVAL(blr->req->vwv+3, 0); files_struct *fsp = blr->fsp; uint16 num_ulocks = SVAL(blr->req->vwv+6, 0); uint16 num_locks = SVAL(blr->req->vwv+7, 0); uint64_t count = (uint64_t)0, offset = (uint64_t)0; uint32 lock_pid; bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES); uint8_t *data; NTSTATUS status = NT_STATUS_OK; data = (uint8_t *)blr->req->buf + ((large_file_format ? 20 : 10)*num_ulocks); /* * Data now points at the beginning of the list * of smb_lkrng structs. */ for(; blr->lock_num < num_locks; blr->lock_num++) { struct byte_range_lock *br_lck = NULL; bool err; lock_pid = get_lock_pid( data, blr->lock_num, large_file_format); count = get_lock_count( data, blr->lock_num, large_file_format); offset = get_lock_offset( data, blr->lock_num, large_file_format, &err); /* * We know err cannot be set as if it was the lock * request would never have been queued. JRA. */ errno = 0; br_lck = do_lock(smbd_messaging_context(), fsp, lock_pid, count, offset, ((locktype & LOCKING_ANDX_SHARED_LOCK) ? READ_LOCK : WRITE_LOCK), WINDOWS_LOCK, True, &status, &blr->blocking_pid); TALLOC_FREE(br_lck); if (NT_STATUS_IS_ERR(status)) { break; } } if(blr->lock_num == num_locks) { /* * Success - we got all the locks. */ DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n", fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) ); reply_lockingX_success(blr); return True; } if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) && !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) { /* * We have other than a "can't get lock" * error. Free any locks we had and return an error. * Return True so we get dequeued. */ blocking_lock_reply_error(blr, status); return True; } /* * Still can't get all the locks - keep waiting. */ DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \ Waiting....\n", blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum)); return False; } /**************************************************************************** Attempt to get the posix lock request from a SMBtrans2 call. Returns True if we want to be removed from the list. *****************************************************************************/ static bool process_trans2(blocking_lock_record *blr) { char params[2]; NTSTATUS status; struct byte_range_lock *br_lck = do_lock(smbd_messaging_context(), blr->fsp, blr->lock_pid, blr->count, blr->offset, blr->lock_type, blr->lock_flav, True, &status, &blr->blocking_pid); TALLOC_FREE(br_lck); if (!NT_STATUS_IS_OK(status)) { if (ERROR_WAS_LOCK_DENIED(status)) { /* Still can't get the lock, just keep waiting. */ return False; } /* * We have other than a "can't get lock" * error. Send an error and return True so we get dequeued. */ blocking_lock_reply_error(blr, status); return True; } /* We finally got the lock, return success. */ SSVAL(params,0,0); /* Fake up max_data_bytes here - we know it fits. */ send_trans2_replies(blr->fsp->conn, blr->req, params, 2, NULL, 0, 0xffff); return True; } /**************************************************************************** Process a blocking lock SMB. Returns True if we want to be removed from the list. *****************************************************************************/ static bool blocking_lock_record_process(blocking_lock_record *blr) { switch(blr->req->cmd) { case SMBlockingX: return process_lockingX(blr); case SMBtrans2: case SMBtranss2: return process_trans2(blr); default: DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n")); exit_server("PANIC - unknown type on blocking lock queue"); } return False; /* Keep compiler happy. */ } /**************************************************************************** Cancel entries by fnum from the blocking lock pending queue. *****************************************************************************/ void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck) { blocking_lock_record *blr, *next = NULL; for(blr = blocking_lock_queue; blr; blr = next) { unsigned char locktype = 0; next = blr->next; if (blr->fsp->fnum != fsp->fnum) { continue; } if (blr->req->cmd == SMBlockingX) { locktype = CVAL(blr->req->vwv+3, 0); } DEBUG(10, ("remove_pending_lock_requests_by_fid - removing " "request type %d for file %s fnum = %d\n", blr->req->cmd, fsp->fsp_name, fsp->fnum)); brl_lock_cancel(br_lck, blr->lock_pid, procid_self(), blr->offset, blr->count, blr->lock_flav); blocking_lock_cancel(fsp, blr->lock_pid, blr->offset, blr->count, blr->lock_flav, locktype, NT_STATUS_RANGE_NOT_LOCKED); /* We're closing the file fsp here, so ensure * we don't have a dangling pointer. */ blr->fsp = NULL; } } /**************************************************************************** Delete entries by mid from the blocking lock pending queue. Always send reply. *****************************************************************************/ void remove_pending_lock_requests_by_mid(int mid) { blocking_lock_record *blr, *next = NULL; for(blr = blocking_lock_queue; blr; blr = next) { files_struct *fsp; struct byte_range_lock *br_lck; next = blr->next; if (blr->req->mid != mid) { continue; } fsp = blr->fsp; br_lck = brl_get_locks(talloc_tos(), fsp); if (br_lck) { DEBUG(10, ("remove_pending_lock_requests_by_mid - " "removing request type %d for file %s fnum " "= %d\n", blr->req->cmd, fsp->fsp_name, fsp->fnum )); brl_lock_cancel(br_lck, blr->lock_pid, procid_self(), blr->offset, blr->count, blr->lock_flav); TALLOC_FREE(br_lck); } blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT); DLIST_REMOVE(blocking_lock_queue, blr); TALLOC_FREE(blr); } } /**************************************************************************** Is this mid a blocking lock request on the queue ? *****************************************************************************/ bool blocking_lock_was_deferred(int mid) { blocking_lock_record *blr, *next = NULL; for(blr = blocking_lock_queue; blr; blr = next) { next = blr->next; if(blr->req->mid == mid) { return True; } } return False; } /**************************************************************************** Set a flag as an unlock request affects one of our pending locks. *****************************************************************************/ static void received_unlock_msg(struct messaging_context *msg, void *private_data, uint32_t msg_type, struct server_id server_id, DATA_BLOB *data) { DEBUG(10,("received_unlock_msg\n")); process_blocking_lock_queue(); } /**************************************************************************** Process the blocking lock queue. Note that this is only called as root. *****************************************************************************/ static void process_blocking_lock_queue(void) { struct timeval tv_curr = timeval_current(); blocking_lock_record *blr, *next = NULL; bool recalc_timeout = False; /* * Go through the queue and see if we can get any of the locks. */ for (blr = blocking_lock_queue; blr; blr = next) { next = blr->next; /* * Go through the remaining locks and try and obtain them. * The call returns True if all locks were obtained successfully * and False if we still need to wait. */ if(blocking_lock_record_process(blr)) { struct byte_range_lock *br_lck = brl_get_locks( talloc_tos(), blr->fsp); if (br_lck) { brl_lock_cancel(br_lck, blr->lock_pid, procid_self(), blr->offset, blr->count, blr->lock_flav); TALLOC_FREE(br_lck); } DLIST_REMOVE(blocking_lock_queue, blr); TALLOC_FREE(blr); recalc_timeout = True; continue; } /* * We couldn't get the locks for this record on the list. * If the time has expired, return a lock error. */ if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) { struct byte_range_lock *br_lck = brl_get_locks( talloc_tos(), blr->fsp); /* * Lock expired - throw away all previously * obtained locks and return lock error. */ if (br_lck) { DEBUG(5,("process_blocking_lock_queue: " "pending lock fnum = %d for file %s " "timed out.\n", blr->fsp->fnum, blr->fsp->fsp_name )); brl_lock_cancel(br_lck, blr->lock_pid, procid_self(), blr->offset, blr->count, blr->lock_flav); TALLOC_FREE(br_lck); } blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT); DLIST_REMOVE(blocking_lock_queue, blr); TALLOC_FREE(blr); recalc_timeout = True; } } if (recalc_timeout) { recalc_brl_timeout(); } } /**************************************************************************** Handle a cancel message. Lock already moved onto the cancel queue. *****************************************************************************/ #define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS)) static void process_blocking_lock_cancel_message(struct messaging_context *ctx, void *private_data, uint32_t msg_type, struct server_id server_id, DATA_BLOB *data) { NTSTATUS err; const char *msg = (const char *)data->data; blocking_lock_record *blr; if (data->data == NULL) { smb_panic("process_blocking_lock_cancel_message: null msg"); } if (data->length != MSG_BLOCKING_LOCK_CANCEL_SIZE) { DEBUG(0, ("process_blocking_lock_cancel_message: " "Got invalid msg len %d\n", (int)data->length)); smb_panic("process_blocking_lock_cancel_message: bad msg"); } memcpy(&blr, msg, sizeof(blr)); memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS)); DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n", nt_errstr(err) )); blocking_lock_reply_error(blr, err); DLIST_REMOVE(blocking_lock_cancelled_queue, blr); TALLOC_FREE(blr); } /**************************************************************************** Send ourselves a blocking lock cancelled message. Handled asynchronously above. *****************************************************************************/ bool blocking_lock_cancel(files_struct *fsp, uint32 lock_pid, uint64_t offset, uint64_t count, enum brl_flavour lock_flav, unsigned char locktype, NTSTATUS err) { char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE]; blocking_lock_record *blr; if (!blocking_lock_cancel_state) { /* Register our message. */ messaging_register(smbd_messaging_context(), NULL, MSG_SMB_BLOCKING_LOCK_CANCEL, process_blocking_lock_cancel_message); blocking_lock_cancel_state = True; } for (blr = blocking_lock_queue; blr; blr = blr->next) { if (fsp == blr->fsp && lock_pid == blr->lock_pid && offset == blr->offset && count == blr->count && lock_flav == blr->lock_flav) { break; } } if (!blr) { return False; } /* Check the flags are right. */ if (blr->req->cmd == SMBlockingX && (locktype & LOCKING_ANDX_LARGE_FILES) != (CVAL(blr->req->vwv+3, 0) & LOCKING_ANDX_LARGE_FILES)) { return False; } /* Move to cancelled queue. */ DLIST_REMOVE(blocking_lock_queue, blr); DLIST_ADD(blocking_lock_cancelled_queue, blr); /* Create the message. */ memcpy(msg, &blr, sizeof(blr)); memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS)); messaging_send_buf(smbd_messaging_context(), procid_self(), MSG_SMB_BLOCKING_LOCK_CANCEL, (uint8 *)&msg, sizeof(msg)); return True; }