dev_clone (9)

Leading comments

Copyright (c) 2008 Konstantin Belousov
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
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(The comments found at the beginning of the groff file "man9/dev_clone.9freebsd".)

NAME

dev_clone drain_dev_clone_events - eventhandler for name-based device cloning in devfs

SYNOPSIS

In sys/param.h In sys/conf.h Ft void Fn clone_handler void *arg struct ucred *cr char *name int namelen struct cdev **dev

EVENTHANDLER_REGISTER(dev_clone, clone_handler, arg, priority);

Ft void Fn drain_dev_clone_events

DESCRIPTION

A device driver may register a listener that will be notified each time a name lookup on the devfs(5) mount point fails to find the vnode. A listener shall be registered for the dev_clone event. When called, it is supplied with the first argument arg that was specified at handler registration time, appropriate credentials cr and a name name of length 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 dev argument.

The Fn drain_dev_clone_events function is a barrier. It is guaranteed that all calls to eventhandlers for dev_clone that were started before Fn drain_dev_clone_events call, are finished before it returns control.

SEE ALSO

devfs(5), namei(9)