1.\" Copyright (c) 2008 Konstantin Belousov 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd January 3, 2009 28.Dt DEV_CLONE 9 29.Os 30.Sh NAME 31.Nm dev_clone , 32.Nm drain_dev_clone_events 33.Nd eventhandler for name-based device cloning in devfs 34.Sh SYNOPSIS 35.In sys/param.h 36.In sys/conf.h 37.Ft void 38.Fn clone_handler "void *arg" "struct ucred *cr" "char *name" "int namelen" "struct cdev **dev" 39.Bd -literal 40EVENTHANDLER_REGISTER(dev_clone, clone_handler, arg, priority); 41.Ed 42.Ft void 43.Fn drain_dev_clone_events 44.Sh DESCRIPTION 45A device driver may register a listener that will be notified each time 46a name lookup on the 47.Xr devfs 5 48mount point fails to find the vnode. 49A listener shall be registered for the 50.Va dev_clone 51event. 52When called, it is supplied with the first argument 53.Va arg 54that was specified at handler registration time, 55appropriate credentials 56.Va cr , 57and a name 58.Va name 59of length 60.Va namelen 61that we look for. 62If the handler decides that the name is appropriate and wants to create the device 63that will be associated with the name, it should return it to devfs 64in the 65.Va dev 66argument. 67.Pp 68The 69.Fn drain_dev_clone_events 70function is a barrier. 71It is guaranteed that all calls to eventhandlers for 72.Nm dev_clone 73that were started before 74.Fn drain_dev_clone_events 75call, are finished before it returns control. 76.Sh SEE ALSO 77.Xr devfs 5 , 78.Xr namei 9 79