1.\" $OpenBSD: getpass.3,v 1.9 2001/12/07 23:56:09 millert 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.Dd December 7, 2001 35.Dt GETPASS 3 36.Os 37.Sh NAME 38.Nm getpass 39.Nd get a password 40.Sh SYNOPSIS 41.Fd #include <pwd.h> 42.Fd #include <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.Fn getpass 52displays the prompt on the standard error output and reads from the standard 53input. 54.Pp 55The password may be up to 56.Dv _PASSWORD_LEN 57(currently 128, as defined in the 58.Aq Pa pwd.h 59include file) 60characters in length. 61Any additional 62characters and the terminating newline character are discarded. 63.Pp 64.Fn getpass 65turns off character echoing while reading the password. 66.Pp 67The calling process should zero the password as soon as possible to 68avoid leaving the cleartext password visible in the process's address 69space. 70.Sh RETURN VALUES 71Upon successful completion, 72.Fn getpass 73returns a pointer to a null-terminated string of at most 74.Dv _PASSWORD_LEN 75characters. 76If an error is encountered, the terminal state is restored and 77a null pointer is returned. 78.Sh ERRORS 79.Bl -tag -width Er 80.It Bq Er EINTR 81The 82.Fn getpass 83function was interrupted by a signal. 84.It Bq Er EIO 85The process is a member of a background process attempting to read 86from its controlling terminal, the process is ignoring or blocking 87the SIGTTIN signal or the process group is orphaned. 88.It Bq Er EMFILE 89The process has already reached its limit for open file descriptors. 90.It Bq Er ENFILE 91The system file table is full. 92.El 93.Sh FILES 94.Bl -tag -width /dev/tty -compact 95.It Pa /dev/tty 96.El 97.Sh SEE ALSO 98.Xr crypt 3 , 99.Xr readpassphrase 3 100.Sh STANDARDS 101Historically, 102.Bx 103versions of 104.Fn getpass 105have accepted a password on the standard input if 106.Pa /dev/tty 107is unavailable. 108This contradicts 109.St -xpg4.2 110but the 111.Ox 112implementation is conformant in all other respects. 113.Sh HISTORY 114A 115.Fn getpass 116function appeared in 117.At v7 . 118.Sh BUGS 119The 120.Fn getpass 121function leaves its result in an internal static object and returns 122a pointer to that object. 123Subsequent calls to 124.Fn getpass 125will modify the same object. 126