NAME

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

SYNOPSIS

     #include <sys/param.h>
     #include <sys/conf.h>

     void
     clone_handler(void *arg, struct ucred *cr, char *name, int namelen, struct cdev **dev);

     EVENTHANDLER_REGISTER(dev_clone, clone_handler, arg, priority);

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

SEE ALSO

     devfs(5), namei(9)