1.\" $OpenBSD: readpassphrase.3,v 1.3 2001/08/06 10:42:25 mpech Exp $ 2.\" 3.\" Copyright (c) 2000 Todd C. Miller <Todd.Miller@courtesan.com> 4.\" 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. The name of the author may not be used to endorse or promote products 15.\" derived from this software without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 18.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 19.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 20.\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 21.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 22.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 23.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 25.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 26.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27.\" 28.\" $FreeBSD$ 29.\" 30.Dd November 20, 2000 31.Dt READPASSPHRASE 3 32.Os 33.Sh NAME 34.Nm readpassphrase 35.Nd get a passphrase from the user 36.Sh SYNOPSIS 37.In readpassphrase.h 38.Ft "char *" 39.Fn readpassphrase "const char *prompt" "char *buf" "size_t bufsiz" "int flags" 40.Sh DESCRIPTION 41The 42.Fn readpassphrase 43function displays a prompt to, and reads in a passphrase from, 44.Pa /dev/tty . 45If this file is inaccessible 46and the 47.Dv RPP_REQUIRE_TTY 48flag is not set, 49.Fn readpassphrase 50displays the prompt on the standard error output and reads from the standard 51input. 52In this case it is generally not possible to turn off echo. 53.Pp 54Up to 55.Fa bufsiz 56\- 1 characters (one is for the 57.Dv NUL ) 58are read into the provided buffer 59.Fa buf . 60Any additional 61characters and the terminating newline (or return) character are discarded. 62.Pp 63.Fn readpassphrase 64takes the following optional 65.Fa flags : 66.Pp 67.Bl -tag -width ".Dv RPP_REQUIRE_TTY" -compact 68.It Dv RPP_ECHO_OFF 69turn off echo (default behavior) 70.It Dv RPP_ECHO_ON 71leave echo on 72.It Dv RPP_REQUIRE_TTY 73fail if there is no tty 74.It Dv RPP_FORCELOWER 75force input to lower case 76.It Dv RPP_FORCEUPPER 77force input to upper case 78.It Dv RPP_SEVENBIT 79strip the high bit from input 80.El 81.Pp 82The calling process should zero the passphrase as soon as possible to 83avoid leaving the cleartext passphrase visible in the process's address 84space. 85.Sh RETURN VALUES 86On success, 87.Fn readpassphrase 88returns a pointer to the null-terminated passphrase. 89If the 90.Dv RPP_REQUIRE_TTY 91flag is set and 92.Pa /dev/tty 93is inaccessible, 94.Fn readpassphrase 95returns a 96.Dv NULL 97pointer. 98.Sh EXAMPLES 99The following code fragment will read a passphrase from 100.Pa /dev/tty 101into the buffer 102.Fa passbuf . 103.Bd -literal -offset indent 104char passbuf[1024]; 105 106\&... 107 108if (readpassphrase("Response: ", passbuf, sizeof(passbuf), 109 RPP_REQUIRE_TTY) == NULL) 110 errx(1, "unable to read passphrase"); 111 112if (compare(transform(passbuf), epass) != 0) 113 errx(1, "bad passphrase"); 114 115\&... 116 117memset(passbuf, 0, sizeof(passbuf)); 118.Ed 119.Sh FILES 120.Bl -tag -width ".Pa /dev/tty" -compact 121.It Pa /dev/tty 122.El 123.Sh SEE ALSO 124.Xr getpass 3 125.Sh HISTORY 126The 127.Fn readpassphrase 128function first appeared in 129.Ox 2.9 . 130