blocking.c

来自「samba-3.0.22.tar.gz 编译smb服务器的源码」· C语言 代码 · 共 703 行 · 第 1/2 页

	set_message_end(outbuf, p+nread);
	
	DEBUG(3, ( "process_lockread file = %s, fnum=%d num=%lu nread=%ld\n",
		   fsp->fsp_name, fsp->fnum, (unsigned long)numtoread, (long)nread ) );
	
	send_blocking_reply(outbuf,outsize);
	return True;
}

/****************************************************************************
 Attempt to finish off getting all pending blocking locks for a lock call.
 Returns True if we want to be removed from the list.
*****************************************************************************/

static BOOL process_lock(blocking_lock_record *blr)
{
	char *outbuf = get_OutBuffer();
	char *inbuf = blr->inbuf;
	int outsize;
	SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
	NTSTATUS status;
	connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
	files_struct *fsp = blr->fsp;
	BOOL my_lock_ctx = False;

	count = IVAL_TO_SMB_OFF_T(inbuf,smb_vwv1);
	offset = IVAL_TO_SMB_OFF_T(inbuf,smb_vwv3);

	errno = 0;
	status = do_lock_spin(fsp, conn, SVAL(inbuf,smb_pid), count, offset, WRITE_LOCK, &my_lock_ctx);
	if (NT_STATUS_IS_ERR(status)) {
		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. Send an error.
			 * Return True so we get dequeued.
			 */
			
			blocking_lock_reply_error(blr, status);
			return True;
		}
		/*
		 * Still can't get the lock - keep waiting.
		 */
		DEBUG(10,("process_lock: failed to get lock for file = %s. Still waiting....\n",
			  fsp->fsp_name));
		return False;
	}

	/*
	 * Success - we got the lock.
	 */
	
	DEBUG(3,("process_lock : file=%s fnum=%d offset=%.0f count=%.0f\n",
		 fsp->fsp_name, fsp->fnum, (double)offset, (double)count));
	
	construct_reply_common(inbuf, outbuf);
	outsize = set_message(outbuf,0,0,True);
	send_blocking_reply(outbuf,outsize);
	return True;
}

/****************************************************************************
 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)
{
	char *inbuf = blr->inbuf;
	unsigned char locktype = CVAL(inbuf,smb_vwv3);
	files_struct *fsp = blr->fsp;
	connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
	uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
	uint16 num_locks = SVAL(inbuf,smb_vwv7);
	SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
	uint16 lock_pid;
	BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
	char *data;
	BOOL my_lock_ctx = False;
	NTSTATUS status = NT_STATUS_OK;

	data = smb_buf(inbuf) + ((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++) {
		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;
		status = do_lock_spin(fsp,conn,lock_pid,count,offset, 
				 ((locktype & 1) ? READ_LOCK : WRITE_LOCK), &my_lock_ctx);
		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;
	} else 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;
}

/****************************************************************************
 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->com_type) {
		case SMBlock:
			return process_lock(blr);
		case SMBlockread:
			return process_lockread(blr);
		case SMBlockingX:
			return process_lockingX(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. */
}

/****************************************************************************
 Delete entries by fnum from the blocking lock pending queue.
*****************************************************************************/

void remove_pending_lock_requests_by_fid(files_struct *fsp)
{
	blocking_lock_record *blr, *next = NULL;

	for(blr = blocking_lock_queue; blr; blr = next) {
		next = blr->next;
		if(blr->fsp->fnum == fsp->fnum) {

			DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));

			brl_unlock(blr->fsp->dev, blr->fsp->inode, blr->fsp->fnum,
				blr->lock_pid, procid_self(), blr->fsp->conn->cnum,
				blr->offset, blr->count, True, NULL, NULL);

			free_blocking_lock_record(blr);
		}
	}
}

/****************************************************************************
 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) {
		next = blr->next;
		if(SVAL(blr->inbuf,smb_mid) == mid) {
			files_struct *fsp = blr->fsp;

			DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));

			blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
			brl_unlock(blr->fsp->dev, blr->fsp->inode, blr->fsp->fnum,
				blr->lock_pid, procid_self(), blr->fsp->conn->cnum,
				blr->offset, blr->count, True, NULL, NULL);
			free_blocking_lock_record(blr);
		}
	}
}

/****************************************************************************
  Set a flag as an unlock request affects one of our pending locks.
*****************************************************************************/

static void received_unlock_msg(int msg_type, struct process_id src,
				void *buf, size_t len)
{
	DEBUG(10,("received_unlock_msg\n"));
	process_blocking_lock_queue(time(NULL));
}

/****************************************************************************
 Return the number of seconds to the next blocking locks timeout, or default_timeout
*****************************************************************************/

unsigned blocking_locks_timeout(unsigned default_timeout)
{
	unsigned timeout = default_timeout;
	time_t t;
	blocking_lock_record *blr = blocking_lock_queue;

	/* note that we avoid the time() syscall if there are no blocking locks */
	if (!blr)
		return timeout;

	t = time(NULL);

	for (; blr; blr = blr->next) {
		if ((blr->expire_time != (time_t)-1) &&
					(timeout > (blr->expire_time - t))) {
			timeout = blr->expire_time - t;
		}
	}

	if (timeout < 1)
		timeout = 1;

	return timeout;
}

/****************************************************************************
 Process the blocking lock queue. Note that this is only called as root.
*****************************************************************************/

void process_blocking_lock_queue(time_t t)
{
	blocking_lock_record *blr, *next = NULL;

	/*
	 * Go through the queue and see if we can get any of the locks.
	 */

	for (blr = blocking_lock_queue; blr; blr = next) {
		connection_struct *conn = NULL;
		uint16 vuid;
		files_struct *fsp = NULL;

		next = blr->next;

		/*
		 * Ensure we don't have any old chain_fsp values
		 * sitting around....
		 */
		chain_size = 0;
		file_chain_reset();
		fsp = blr->fsp;

		conn = conn_find(SVAL(blr->inbuf,smb_tid));
		vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
				SVAL(blr->inbuf,smb_uid);

		DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
			fsp->fnum, fsp->fsp_name ));

		if((blr->expire_time != -1) && (blr->expire_time <= t)) {
			/*
			 * Lock expired - throw away all previously
			 * obtained locks and return lock error.
			 */
			DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
				fsp->fnum, fsp->fsp_name ));

			brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
				blr->lock_pid, procid_self(), conn->cnum,
				blr->offset, blr->count, True, NULL, NULL);

			blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
			free_blocking_lock_record(blr);
			continue;
		}

		if(!change_to_user(conn,vuid)) {
			DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
				vuid ));
			/*
			 * Remove the entry and return an error to the client.
			 */
			blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);

			brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
					blr->lock_pid, procid_self(), conn->cnum,
					blr->offset, blr->count, True, NULL, NULL);

			free_blocking_lock_record(blr);
			continue;
		}

		if(!set_current_service(conn,SVAL(blr->inbuf,smb_flg),True)) {
			DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
			/*
			 * Remove the entry and return an error to the client.
			 */
			blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);

			brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
					blr->lock_pid, procid_self(), conn->cnum,
					blr->offset, blr->count, True, NULL, NULL);

			free_blocking_lock_record(blr);
			change_to_root_user();
			continue;
		}

		/*
		 * 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)) {

			brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
					blr->lock_pid, procid_self(), conn->cnum,
					blr->offset, blr->count, True, NULL, NULL);

			free_blocking_lock_record(blr);
		}
		change_to_root_user();
	}
}