Introduce readpassphrase(3), a superset of getpass(3). This

comes originally from Todd Miller.

Obtained from:	OpenBSD

1 files changed, 118 insertions, 0 deletions

diff --git a/lib/libc/gen/readpassphrase.3 b/lib/libc/gen/readpassphrase.3
new file mode 100644
index 0000000..2fe97bf
--- /dev/null
+++ b/lib/libc/gen/readpassphrase.3
@@ -0,0 +1,118 @@
+.\"	$OpenBSD: readpassphrase.3,v 1.3 2001/08/06 10:42:25 mpech Exp $
+.\"	$FreeBSD$
+.\"
+.\" Copyright (c) 2000 Todd C. Miller <Todd.Miller@courtesan.com>
+.\" 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.
+.\" 3. The name of the author may not be used to endorse or promote products
+.\"    derived from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
+.\"
+.Dd November 20, 2000
+.Dt READPASSPHRASE 3
+.Os
+.Sh NAME
+.Nm readpassphrase
+.Nd get a passphrase from the user
+.Sh SYNOPSIS
+.Fd #include <readpassphrase.h>
+.Ft char *
+.Fn readpassphrase "const char *prompt" "char *buf" "size_t bufsiz" "int flags"
+.Sh DESCRIPTION
+The
+.Fn readpassphrase
+function displays a prompt to, and reads in a passphrase from,
+.Pa /dev/tty .
+If this file is inaccessible
+and the
+.Dv RPP_REQUIRE_TTY
+flag is not set,
+.Fn readpassphrase
+displays the prompt on the standard error output and reads from the standard
+input.
+In this case it is generally not possible to turn off echo.
+.Pp
+Up to
+.Fa bufsiz
+- 1 characters (one is for the NUL) are read into the provided buffer
+.Fa buf .
+Any additional
+characters and the terminating newline (or return) character are discarded.
+.Pp
+.Fn readpassphrase
+takes the following optional
+.Fa flags :
+.Pp
+.Bd -literal -offset indent -compact
+RPP_ECHO_OFF		turn off echo (default behavior)
+RPP_ECHO_ON		leave echo on
+RPP_REQUIRE_TTY		fail if there is no tty
+RPP_FORCELOWER		force input to lower case
+RPP_FORCEUPPER		force input to upper case
+RPP_SEVENBIT		strip the high bit from input
+.Ed
+.Pp
+The calling process should zero the passphrase as soon as possible to
+avoid leaving the cleartext passphrase visible in the process's address
+space.
+.Sh RETURN VALUES
+On success,
+.Fn readpassphrase
+returns a pointer to the null-terminated passphrase.
+If the
+.Dv RPP_REQUIRE_TTY
+flag is set and
+.Pa /dev/tty
+is inaccessible,
+.Fn readpassphrase
+returns a null pointer.
+.Sh EXAMPLES
+The following code fragment will read a passphrase from
+.Pa /dev/tty
+into the buffer
+.Fa passbuf.
+.Bd -literal -offset indent
+char passbuf[1024];
+
+\&...
+
+if (readpassphrase("Response: ", passbuf, sizeof(passbuf),
+    RPP_REQUIRE_TTY) == NULL)
+	errx(1, "unable to read passphrase");
+
+if (compare(transform(passbuf), epass) != 0)
+	errx(1, "bad passphrase");
+
+\&...
+
+memset(passbuf, 0, sizeof(passbuf));
+.Ed
+.Sh FILES
+.Bl -tag -width /dev/tty -compact
+.It Pa /dev/tty
+.El
+.Sh SEE ALSO
+.Xr getpass 3
+.Sh HISTORY
+The
+.Fn readpassphrase
+function first appeared in
+.Ox 2.9 .