Copyright (c) 2008 Konstantin Belousov
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$FreeBSD: releng/10.2/share/man/man9/dev_clone.9 186714 2009-01-03 10:37:38Z brueffer $
.Dd January 3, 2009 .Dt DEV_CLONE 9 .Os .Sh NAME .Nm dev_clone , .Nm drain_dev_clone_events .Nd eventhandler for name-based device cloning in devfs .Sh SYNOPSIS n sys/param.h n sys/conf.h .Ft void .Fn clone_handler "void *arg" "struct ucred *cr" "char *name" "int namelen" "struct cdev **dev" d -literal EVENTHANDLER_REGISTER(dev_clone, clone_handler, arg, priority); .Ed .Ft void .Fn drain_dev_clone_events .Sh DESCRIPTION A device driver may register a listener that will be notified each time a name lookup on the .Xr devfs 5 mount point fails to find the vnode. A listener shall be registered for the .Va dev_clone event. When called, it is supplied with the first argument .Va arg that was specified at handler registration time, appropriate credentials .Va cr , and a name .Va name of length .Va namelen that we look for. If the handler decides that the name is appropriate and wants to create the device that will be associated with the name, it should return it to devfs in the .Va dev argument.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
$FreeBSD: releng/10.2/share/man/man9/dev_clone.9 186714 2009-01-03 10:37:38Z brueffer $
.Dd January 3, 2009 .Dt DEV_CLONE 9 .Os .Sh NAME .Nm dev_clone , .Nm drain_dev_clone_events .Nd eventhandler for name-based device cloning in devfs .Sh SYNOPSIS n sys/param.h n sys/conf.h .Ft void .Fn clone_handler "void *arg" "struct ucred *cr" "char *name" "int namelen" "struct cdev **dev" d -literal EVENTHANDLER_REGISTER(dev_clone, clone_handler, arg, priority); .Ed .Ft void .Fn drain_dev_clone_events .Sh DESCRIPTION A device driver may register a listener that will be notified each time a name lookup on the .Xr devfs 5 mount point fails to find the vnode. A listener shall be registered for the .Va dev_clone event. When called, it is supplied with the first argument .Va arg that was specified at handler registration time, appropriate credentials .Va cr , and a name .Va name of length .Va namelen that we look for. If the handler decides that the name is appropriate and wants to create the device that will be associated with the name, it should return it to devfs in the .Va dev argument.
p The .Fn drain_dev_clone_events function is a barrier. It is guaranteed that all calls to eventhandlers for .Nm dev_clone that were started before .Fn drain_dev_clone_events call, are finished before it returns control. .Sh SEE ALSO .Xr devfs 5 , .Xr namei 9