f14fb60209
* Updating common/lib * Updating lib/csu * Updating lib/libc * Updating libexec/ld.elf_so * Corrected test on __minix in featuretest to actually follow the meaning of the comment. * Cleaned up _REENTRANT-related defintions. * Disabled -D_REENTRANT for libfetch * Removing some unneeded __NBSD_LIBC defines and tests Change-Id: Ic1394baef74d11b9f86b312f5ff4bbc3cbf72ce2
201 lines
5.3 KiB
Groff
201 lines
5.3 KiB
Groff
.\" $NetBSD: getpass.3,v 1.22 2012/04/14 10:34:29 wiz Exp $
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.\"
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.\" Copyright (c) 1989, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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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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.\" @(#)getpass.3 8.1 (Berkeley) 6/4/93
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.\"
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.Dd April 13, 2012
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.Dt GETPASS 3
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.Os
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.Sh NAME
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.Nm getpass
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.Nd get a password
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft char *
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.Fn getpass "const char *prompt"
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.Ft char *
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.Fn getpass_r "const char *prompt" "char *buf" "size_t buflen"
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.Ft char *
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.Fn getpassfd "const char *prompt" "char *buf" "size_t buflen" "int *fd" "int flags" "int timeout"
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.Sh DESCRIPTION
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The
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.Fn getpass
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function displays a prompt to, and reads in a password from,
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.Pa /dev/tty .
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If this file is not accessible,
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.Fn getpass
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displays the prompt on the standard error output and reads from the standard
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input.
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.Pp
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The password may be up to
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.Xr sysconf 3
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.Dv _SC_PASS_MAX
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characters in length.
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Any additional
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characters and the terminating newline character are discarded.
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.Pp
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.Fn getpass
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turns off character echoing while reading the password.
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.Pp
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.Fn getpass_r
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is similar to
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.Fn getpass
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only it puts its result in
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.Fa buf
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for up to
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.Fa buflen
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characters.
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If the
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.Fa buf
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argument is
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.Dv NULL ,
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then a buffer will be dynamically allocated.
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.Pp
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The
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.Fn getpassfd
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function allows one to specify the three file descriptors corresponding to
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.Dv stdin ,
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.Dv stdout ,
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and
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.Dv stderr
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in the
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.Fa fd
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argument, or if
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.Fa fd
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is
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.Dv NULL ,
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.Fn getpassfd
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first attempts to open
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.Pa /dev/tty
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and if that fails, defaults to
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.Dv STDIN_FILENO
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for input and
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.Dv STDERR_FILENO
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for output.
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.Pp
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The behavior of
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.Fn getpassfd
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is controlled by the
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.Fa flags
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argument:
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.Bl -tag -width GETPASS_FORCE_UPPER
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.It Dv GETPASS_NEED_TTY
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Fail if we are unable to set the tty modes like we want.
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.It Dv GETPASS_FAIL_EOF
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Fail if we get the end-of-file character instead of returning the result so far.
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.It Dv GETPASS_BUF_LIMIT
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Beep when the buffer limit is reached, instead of silently absorbing it.
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.It Dv GETPASS_NO_SIGNAL
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Don't make ttychars send signals.
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.It Dv GETPASS_NO_BEEP
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Don't beep if we erase past the beginning of the buffer or we try to enter past
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the end.
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.It Dv GETPASS_ECHO_STAR
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Echo a
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.Sq *
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for each character entered.
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.It Dv GETPASS_ECHO
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Echo characters as they are typed.
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.It Dv GETPASS_ECHO_NL
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Echoes a newline if successful.
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.It Dv GETPASS_7BIT
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Mask the high bit for each entered character.
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.It Dv GETPASS_FORCE_LOWER
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Lowercase each entered character.
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.It Dv GETPASS_FORCE_UPPER
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Uppercase each entered character.
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.El
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.Pp
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Finally if the
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.Fa timeout
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argument is non zero,
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.Fn getpassfd
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will wait for
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.Fa timeout
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seconds for input after each character before returning an error, instead of
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waiting forever.
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.Sh RETURN VALUES
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The
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.Fn getpass
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function returns a pointer to the NUL terminated password, or an empty
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string on error.
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The
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.Fn getpass_r
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and
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.Fn getpassfd
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functions return a pointer to the NUL terminated password, or
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.Dv NULL
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on error.
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.Sh FILES
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.Bl -tag -width /dev/tty -compact
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.It Pa /dev/tty
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.El
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.Sh SEE ALSO
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.Xr crypt 3
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.Sh STANDARDS
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The
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.Fn getpass
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function appeared in
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.St -susv2 ,
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but it was already marked as legacy.
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The function was removed in the
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.St -p1003.1-2001
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standard.
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.Sh HISTORY
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A
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.Fn getpass
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function appeared in
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.At v7 .
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The
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.Fn getpass_r
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and
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.Fn getpassfd
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functions appeared in
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.Nx 7.0 .
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.Sh BUGS
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The
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.Fn getpass
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function leaves its result in an internal static object and returns
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a pointer to that object.
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Subsequent calls to
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.Fn getpass
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will modify the same object.
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.Sh SECURITY CONSIDERATIONS
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The calling process should zero the password as soon as possible to
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avoid leaving the cleartext password visible in the process's address
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space.
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.Pp
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Historically
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.Nm
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accepted and returned a password if it could not modify the terminal
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settings to turn echo off (or if the input was not a terminal).
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In this implementation, only terminal input is accepted.
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