.\" Copyright (c) 1989, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" 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. .\" 4. Neither the name of the University 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 REGENTS 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 REGENTS OR 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. .\" .\" @(#)getpass.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD: src/lib/libc/gen/getpass.3,v 1.12 2007/01/09 00:27:54 imp Exp $ .\" .Dd June 4, 1993 .Dt GETPASS 3 .Os .Sh NAME .Nm getpass .Nd get a password .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In pwd.h .In unistd.h .Ft char * .Fn getpass "const char *prompt" .Sh DESCRIPTION The .Fn getpass function displays a prompt to, and reads in a password from, .Pa /dev/tty . If this file is not accessible, .Fn getpass displays the prompt on the standard error output and reads from the standard input. .Pp The password may be up to _PASSWORD_LEN (currently 128) characters in length. Any additional characters and the terminating newline character are discarded. .Pp The .Fn getpass function turns off character echoing while reading the password. .Sh RETURN VALUES The .Fn getpass function returns a pointer to the null terminated password. .Sh FILES .Bl -tag -width /dev/tty -compact .It Pa /dev/tty .El .Sh SEE ALSO .Xr crypt 3 , .Xr readpassphrase 3 .Sh HISTORY A .Fn getpass function appeared in .At v7 . .Sh BUGS The .Fn getpass function leaves its result in an internal static object and returns a pointer to that object. Subsequent calls to .Fn getpass will modify the same object. .Pp The calling process should zero the password as soon as possible to avoid leaving the cleartext password visible in the process's address space. .Pp Upon receipt of a SIGTSTP, the input buffer will be flushed, so any partially typed password must be retyped when the process continues.