getpass.3

早期freebsd实现

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.\"     @(#)getpass.3	8.1 (Berkeley) 6/4/93
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.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.