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Diffstat (limited to 'static/freebsd/man9/devfs_set_cdevpriv.9')
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diff --git a/static/freebsd/man9/devfs_set_cdevpriv.9 b/static/freebsd/man9/devfs_set_cdevpriv.9 new file mode 100644 index 00000000..0cbfd3ee --- /dev/null +++ b/static/freebsd/man9/devfs_set_cdevpriv.9 @@ -0,0 +1,159 @@ +.\" 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 +.\" 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. +.\" +.Dd March 23, 2024 +.Dt DEVFS_CDEVPRIV 9 +.Os +.Sh NAME +.Nm devfs_set_cdevpriv , +.Nm devfs_get_cdevpriv , +.Nm devfs_clear_cdevpriv , +.Nm devfs_foreach_cdevpriv +.Nd manage per-open filedescriptor data for devices +.Sh SYNOPSIS +.In sys/param.h +.In sys/conf.h +.Bd -literal +typedef void d_priv_dtor_t(void *data); +.Ed +.Ft int +.Fn devfs_get_cdevpriv "void **datap" +.Ft int +.Fn devfs_set_cdevpriv "void *priv" "d_priv_dtor_t *dtr" +.Ft void +.Fn devfs_clear_cdevpriv "void" +.Ft int +.Fo devfs_foreach_cdevpriv +.Fa "struct cdev *dev" +.Fa "int (*cb)(void *data, void *arg)" +.Fa "void *arg" +.Fc +.Sh DESCRIPTION +The +.Fn devfs_xxx_cdevpriv +family of functions allows the +.Fa cdev +driver methods to associate some driver-specific data with each +user process +.Xr open 2 +of the device special file. +Currently, functioning of these functions is restricted to the context +of the +.Fa cdevsw +switch method calls performed as +.Xr devfs 4 +operations in response to system calls that use filedescriptors. +.Pp +The +.Fn devfs_set_cdevpriv +function associates a data pointed by +.Va priv +with current calling context (filedescriptor). +The data may be retrieved later, possibly from another call +performed on this filedescriptor, by the +.Fn devfs_get_cdevpriv +function. +The +.Fn devfs_clear_cdevpriv +disassociates previously attached data from context. +Immediately after +.Fn devfs_clear_cdevpriv +finished operating, the +.Va dtr +callback is called, with private data supplied +.Va data +argument. +The +.Fn devfs_clear_cdevpriv +function will be also be called if the open callback +function returns an error code. +.Pp +On the last filedescriptor close, system automatically arranges +.Fn devfs_clear_cdevpriv +call. +.Pp +If successful, the functions return 0. +.Pp +The function +.Fn devfs_set_cdevpriv +returns the following values on error: +.Bl -tag -width Er +.It Bq Er ENOENT +The current call is not associated with some filedescriptor. +.It Bq Er EBUSY +The private driver data is already associated with current +filedescriptor. +.El +.Pp +The function +.Fn devfs_get_cdevpriv +returns the following values on error: +.Bl -tag -width Er +.It Bq Er EBADF +The current call is not associated with some filedescriptor. +.It Bq Er ENOENT +The private driver data was not associated with current +filedescriptor, or +.Fn devfs_clear_cdevpriv +was called. +.El +.Pp +The function +.Fn devfs_foreach_cdevpriv +sequentially calls the function +.Fa cb +for each +.Nm cdevpriv +structure, currently associated with the +.Fa cdev +device. +The iterated +.Nm cdevpriv +data pointer and the user-supplied context +.Fa arg +are passed to the function +.Fa cb . +If +.Fa cb +returns non-zero value, the iteration stops on that element. +The +.Fn devfs_foreach_cdevpriv +returns the return value from the last call to +.Fa cb , +or zero if no +.Nm cdevpriv +data is currently associated with the device. +.Pp +Current implementation of the iterator makes it impossible to use +any blockable locking inside the callback +.Fa cb . +.Sh SEE ALSO +.Xr close 2 , +.Xr open 2 , +.Xr devfs 4 +.Sh HISTORY +The +.Fn devfs_cdevpriv +family of functions first appeared in +.Fx 7.1 . |