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author | kib <kib@FreeBSD.org> | 2008-09-11 11:41:33 +0000 |
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committer | kib <kib@FreeBSD.org> | 2008-09-11 11:41:33 +0000 |
commit | 26d6e1da5df4caa919c9e1e09cd2d85b11089406 (patch) | |
tree | 04ef732de5988d77dddfe213868b69b1658d6c66 /share/man/man9/devfs_set_cdevpriv.9 | |
parent | d397045a7ce348e6d46bdb3a770c367a6db6c67c (diff) | |
download | FreeBSD-src-26d6e1da5df4caa919c9e1e09cd2d85b11089406.zip FreeBSD-src-26d6e1da5df4caa919c9e1e09cd2d85b11089406.tar.gz |
Add a first draft of the cdevpriv(9) documentation
Diffstat (limited to 'share/man/man9/devfs_set_cdevpriv.9')
-rw-r--r-- | share/man/man9/devfs_set_cdevpriv.9 | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/share/man/man9/devfs_set_cdevpriv.9 b/share/man/man9/devfs_set_cdevpriv.9 new file mode 100644 index 0000000..98a3a79 --- /dev/null +++ b/share/man/man9/devfs_set_cdevpriv.9 @@ -0,0 +1,121 @@ +.\" 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. +.\" +.\" $FreeBSD$ +.\" +.Dd September 8, 2008 +.Os +.Dt DEVFS_CDEVPRIV +.Sh NAME +.Nm devfs_set_cdevpriv , +.Nm devfs_get_cdevpriv , +.Nm devfs_clear_cdevpriv +.Nd manage per-open filedescriptor data for devices +.Sh SYNOPSIS +.In sys/param.h +.In sys/conf.h +.Bd -literal +typedef void (*cdevpriv_dtr_t)(void *data); +.Ed +.Ft int +.Fn devfs_get_cdevpriv void **datap +.Ft int +.Fn devfs_set_cdevpriv "void *priv" "cdevpriv_dtr_t dtr" +.Ft void +.Fn devfs_clear_cdevpriv "void" +.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 5 +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. +.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. +.Pp +.Sh SEE ALSO +.Xr open 2 , +.Xr close 2 , +.Xr devfs 5 , +.Xr kern_openat 9 +.Sh HISTORY +The +.Fn devfs_cdevpriv +family of functions first appeared in +.Fx 7.1 . |