1.\" $NetBSD: getpass.3,v 1.9 2002/02/07 07:00:13 ross 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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)getpass.3 8.1 (Berkeley) 6/4/93 35.\" 36.Dd June 4, 1993 37.Dt GETPASS 3 38.Os 39.Sh NAME 40.Nm getpass 41.Nd get a password 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]pwd.h\*[Gt] 46.Fd #include \*[Lt]unistd.h\*[Gt] 47.Ft char * 48.Fn getpass "const char *prompt" 49.Sh DESCRIPTION 50The 51.Fn getpass 52function displays a prompt to, and reads in a password from, 53.Pa /dev/tty . 54If this file is not accessible, 55.Nm 56displays the prompt on the standard error output and reads from the standard 57input. 58.Pp 59The password may be up to _PASSWORD_LEN (currently 128) 60characters in length. 61Any additional 62characters and the terminating newline character are discarded. 63.Pp 64.Nm 65turns off character echoing while reading the password. 66.Sh RETURN VALUES 67.Nm 68returns a pointer to the null terminated password. 69.Sh FILES 70.Bl -tag -width /dev/tty -compact 71.It Pa /dev/tty 72.El 73.Sh SEE ALSO 74.Xr crypt 3 75.Sh HISTORY 76A 77.Nm 78function appeared in 79.At v7 . 80.Sh BUGS 81The 82.Nm 83function leaves its result in an internal static object and returns 84a pointer to that object. 85Subsequent calls to 86.Nm 87will modify the same object. 88.Sh SECURITY CONSIDERATIONS 89The calling process should zero the password as soon as possible to 90avoid leaving the cleartext password visible in the process's address 91space. 92