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freebsd/lib/libc/gen/getpass.3
Joerg Wunsch 7560bb26ff Finally complete my fix for the behaviour of getpass(3) upon receipt
of signals.  Signals are now properly caught, tty state is being
restored, and the previous sigaction triggered.  Upon receipt of a
sigcont, echo is turned off again.

SIGTSTP causes a buffer flush, the man page mentions this.  (Although
i rather think of it as a feature than a bug.)

This is likely to be my last FreeBSD action for 1995, xearth shows
me that our .au guys must already write 1996. :-)
1995-12-31 14:00:25 +00:00

93 lines
3.2 KiB
Groff

.\" Copyright (c) 1989, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
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.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 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
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.\" SUCH DAMAGE.
.\"
.\" @(#)getpass.3 8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt GETPASS 3
.Os
.Sh NAME
.Nm getpass
.Nd get a password
.Sh SYNOPSIS
.Fd #include <pwd.h>
.Fd #include <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,
.Nm 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
.Nm Getpass
turns off character echoing while reading the password.
.Pp
.Sh RETURN VALUES
.Nm Getpass
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
.Sh HISTORY
A
.Nm getpass
function appeared in
.At v7 .
.Sh BUGS
The
.Nm getpass
function leaves its result in an internal static object and returns
a pointer to that object.
Subsequent calls to
.Nm 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.