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