1.\" $NetBSD: getpass.3,v 1.11 2003/08/07 16:42:50 agc Exp $ 2.\" 3.\" Copyright (c) 1989, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)getpass.3 8.1 (Berkeley) 6/4/93 31.\" 32.Dd June 4, 1993 33.Dt GETPASS 3 34.Os 35.Sh NAME 36.Nm getpass 37.Nd get a password 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In pwd.h 42.In unistd.h 43.Ft char * 44.Fn getpass "const char *prompt" 45.Sh DESCRIPTION 46The 47.Fn getpass 48function displays a prompt to, and reads in a password from, 49.Pa /dev/tty . 50If this file is not accessible, 51.Nm 52displays the prompt on the standard error output and reads from the standard 53input. 54.Pp 55The password may be up to _PASSWORD_LEN (currently 128) 56characters in length. 57Any additional 58characters and the terminating newline character are discarded. 59.Pp 60.Nm 61turns off character echoing while reading the password. 62.Sh RETURN VALUES 63.Nm 64returns a pointer to the null terminated password. 65.Sh FILES 66.Bl -tag -width /dev/tty -compact 67.It Pa /dev/tty 68.El 69.Sh SEE ALSO 70.Xr crypt 3 71.Sh HISTORY 72A 73.Nm 74function appeared in 75.At v7 . 76.Sh BUGS 77The 78.Nm 79function leaves its result in an internal static object and returns 80a pointer to that object. 81Subsequent calls to 82.Nm 83will modify the same object. 84.Sh SECURITY CONSIDERATIONS 85The calling process should zero the password as soon as possible to 86avoid leaving the cleartext password visible in the process's address 87space. 88