3e7224dffe
MFC after: 2 weeks PR: 250062 Reviewed by: jilles, 0mp, Ray <i maskray me> Differential Revision: https://reviews.freebsd.org/D26647
187 lines
4.6 KiB
Groff
187 lines
4.6 KiB
Groff
.\"
|
|
.\" Copyright (c) 2002 The FreeBSD Project, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This software includes code contributed to the FreeBSD Project
|
|
.\" by Ryan Younce of North Carolina State University.
|
|
.\"
|
|
.\" 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.
|
|
.\" 3. Neither the name of the FreeBSD Project nor the names of its
|
|
.\" contributors may be used to endorse or promote products derived from
|
|
.\" this software without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE FREEBSD PROJECT 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 FREEBSD PROJECT
|
|
.\" OR ITS 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 October 17, 2020
|
|
.Dt PTSNAME 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm grantpt ,
|
|
.Nm ptsname ,
|
|
.Nm ptsname_r ,
|
|
.Nm unlockpt
|
|
.Nd pseudo-terminal access functions
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In stdlib.h
|
|
.Ft int
|
|
.Fn grantpt "int fildes"
|
|
.Ft "char *"
|
|
.Fn ptsname "int fildes"
|
|
.Ft "int"
|
|
.Fn ptsname_r "int fildes" "char *buffer" "size_t buflen"
|
|
.Ft int
|
|
.Fn unlockpt "int fildes"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn grantpt ,
|
|
.Fn ptsname ,
|
|
and
|
|
.Fn unlockpt
|
|
functions allow access to pseudo-terminal devices.
|
|
These three functions accept a file descriptor that references the
|
|
master half of a pseudo-terminal pair.
|
|
This file descriptor is created with
|
|
.Xr posix_openpt 2 .
|
|
.Pp
|
|
The
|
|
.Fn grantpt
|
|
function is used to establish ownership and permissions
|
|
of the slave device counterpart to the master device
|
|
specified with
|
|
.Fa fildes .
|
|
The slave device's ownership is set to the real user ID
|
|
of the calling process, and the permissions are set to
|
|
user readable-writable and group writable.
|
|
The group owner of the slave device is also set to the
|
|
group
|
|
.Dq Li tty .
|
|
.Pp
|
|
The
|
|
.Fn ptsname
|
|
function returns the full pathname of the slave device
|
|
counterpart to the master device specified with
|
|
.Fa fildes .
|
|
This value can be used
|
|
to subsequently open the appropriate slave after
|
|
.Xr posix_openpt 2
|
|
and
|
|
.Fn grantpt
|
|
have been called.
|
|
.Pp
|
|
The
|
|
.Fn ptsname_r
|
|
function is the thread-safe version of
|
|
.Fn ptsname .
|
|
The caller must provide storage for the results of the full pathname of
|
|
the slave device in the
|
|
.Fa buffer
|
|
and
|
|
.Fa bufsize
|
|
arguments.
|
|
.Pp
|
|
The
|
|
.Fn unlockpt
|
|
function clears the lock held on the pseudo-terminal pair
|
|
for the master device specified with
|
|
.Fa fildes .
|
|
.Sh RETURN VALUES
|
|
.Rv -std grantpt ptsname_r unlockpt
|
|
.Pp
|
|
The
|
|
.Fn ptsname
|
|
function returns a pointer to the name
|
|
of the slave device on success; otherwise a
|
|
.Dv NULL
|
|
pointer is returned.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn grantpt ,
|
|
.Fn ptsname ,
|
|
.Fn ptsname_r
|
|
and
|
|
.Fn unlockpt
|
|
functions may fail and set
|
|
.Va errno
|
|
to:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EBADF
|
|
.Fa fildes
|
|
is not a valid open file descriptor.
|
|
.It Bq Er EINVAL
|
|
.Fa fildes
|
|
is not a master pseudo-terminal device.
|
|
.El
|
|
.Pp
|
|
In addition, the
|
|
.Fn ptsname_r
|
|
function may set
|
|
.Va errno
|
|
to:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ERANGE
|
|
The buffer was too small.
|
|
.El
|
|
.Pp
|
|
In addition, the
|
|
.Fn grantpt
|
|
function may set
|
|
.Va errno
|
|
to:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EACCES
|
|
The slave pseudo-terminal device could not be accessed.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr posix_openpt 2 ,
|
|
.Xr pts 4 ,
|
|
.Xr tty 4
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn ptsname
|
|
function conforms to
|
|
.St -p1003.1-2008 .
|
|
.Pp
|
|
This implementation of
|
|
.Fn grantpt
|
|
and
|
|
.Fn unlockpt
|
|
does not conform to
|
|
.St -p1003.1-2008 ,
|
|
because it depends on
|
|
.Xr posix_openpt 2
|
|
to create the pseudo-terminal device with proper permissions in place.
|
|
It only validates whether
|
|
.Fa fildes
|
|
is a valid pseudo-terminal master device.
|
|
Future revisions of the specification will likely allow this behaviour,
|
|
as stated by the Austin Group.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn grantpt ,
|
|
.Fn ptsname
|
|
and
|
|
.Fn unlockpt
|
|
functions appeared in
|
|
.Fx 5.0 .
|