d5870e1cc6
return in the parent process, but the tty name is available to both the parent and child. Bump date.
166 lines
4.4 KiB
Groff
166 lines
4.4 KiB
Groff
.\" $NetBSD: openpty.3,v 1.14 2008/11/28 07:17:17 dholland Exp $
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.\"
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.\" Copyright (c) 1995
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software developed by the Computer Systems
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.\" Engineering group at Lawrence Berkeley Laboratory under DARPA contract
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.\" BG 91-66 and contributed to Berkeley.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd November 28, 2008
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.Dt OPENPTY 3
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.Os
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.Sh NAME
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.Nm openpty ,
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.Nm login_tty ,
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.Nm forkpty
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.Nd tty utility functions
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.Sh LIBRARY
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.Lb libutil
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.Sh SYNOPSIS
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.In util.h
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.Ft int
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.Fn openpty "int *amaster" "int *aslave" "char *name" "struct termios *termp" "struct winsize *winp"
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.Ft int
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.Fn login_tty "int fd"
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.Ft pid_t
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.Fn forkpty "int *amaster" "char *name" "struct termios *termp" "struct winsize *winp"
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.Sh DESCRIPTION
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The
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.Fn openpty ,
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.Fn login_tty ,
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and
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.Fn forkpty
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functions perform manipulations on ttys and pseudo-ttys.
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.Pp
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The
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.Fn openpty
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function finds an available pseudo-tty and returns file descriptors
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for the master and slave in
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.Fa amaster
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and
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.Fa aslave .
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If
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.Fa name
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is non-null, the filename of the slave is returned in
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.Fa name .
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If
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.Fa termp
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is non-null, the terminal parameters of the slave will be set to the
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values in
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.Fa termp .
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If
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.Fa winp
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is non-null, the window size of the slave will be set to the values in
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.Fa winp .
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.Pp
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The
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.Fn login_tty
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function prepares for a login on the tty
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.Fa fd
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(which may be a real tty device, or the slave of a pseudo-tty as
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returned by
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.Fn openpty )
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by creating a new session, making
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.Fa fd
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the controlling terminal for the current process, setting
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.Fa fd
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to be the standard input, output, and error streams of the current
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process, and closing
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.Fa fd .
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.Pp
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The
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.Fn forkpty
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function combines
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.Fn openpty ,
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.Fn fork ,
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and
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.Fn login_tty
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to create a new process operating in a pseudo-tty.
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The file descriptor of the master side of the pseudo-tty is returned
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(to the parent process only) in
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.Fa amaster .
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The filename of the slave is returned (to both the parent and child
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processes) in
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.Fa name
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if
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.Fa name
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is non-null.
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The
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.Fa termp
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and
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.Fa winp
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parameters, if non-null, will determine the terminal attributes and
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window size of the slave side of the pseudo-tty.
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.Sh RETURN VALUES
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If a call to
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.Fn openpty ,
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.Fn login_tty ,
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or
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.Fn forkpty
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is not successful, -1 is returned and
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.Va errno
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is set to indicate the error.
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Otherwise,
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.Fn openpty ,
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.Fn login_tty ,
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and the child process of
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.Fn forkpty
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return 0, and the parent process of
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.Fn forkpty
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returns the process ID of the child process.
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.Sh FILES
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.Bl -tag -width /dev/[pt]ty[p-zP-T][0-9a-zA-Z] -compact
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.It Pa /dev/[pt]ty[p-zP-T][0-9a-zA-Z]
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.El
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.Sh ERRORS
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.Fn openpty
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will fail if:
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.Bl -tag -width Er
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.It Bq Er ENOENT
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There are no available ttys.
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.It Bq Er EPERM
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The caller was not the superuser and the
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.Xr ptm 4
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device is missing or not configured.
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.El
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.Pp
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.Fn login_tty
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will fail if
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.Fn ioctl
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fails to set
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.Fa fd
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to the controlling terminal of the current process.
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.Fn forkpty
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will fail if either
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.Fn openpty
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or
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.Fn fork
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fails.
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.Sh SEE ALSO
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.Xr fork 2
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