xref: /freebsd/lib/libc/gen/getpass.3 (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
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28.\"     @(#)getpass.3	8.1 (Berkeley) 6/4/93
29.\" $FreeBSD$
30.\"
31.Dd June 4, 1993
32.Dt GETPASS 3
33.Os
34.Sh NAME
35.Nm getpass
36.Nd get a password
37.Sh LIBRARY
38.Lb libc
39.Sh SYNOPSIS
40.In pwd.h
41.In unistd.h
42.Ft char *
43.Fn getpass "const char *prompt"
44.Sh DESCRIPTION
45The
46.Fn getpass
47function displays a prompt to, and reads in a password from,
48.Pa /dev/tty .
49If this file is not accessible,
50.Fn getpass
51displays the prompt on the standard error output and reads from the standard
52input.
53.Pp
54The password may be up to _PASSWORD_LEN (currently 128)
55characters in length.
56Any additional
57characters and the terminating newline character are discarded.
58.Pp
59The
60.Fn getpass
61function turns off character echoing while reading the password.
62.Sh RETURN VALUES
63The
64.Fn getpass
65function returns a pointer to the null terminated password.
66.Sh FILES
67.Bl -tag -width /dev/tty -compact
68.It Pa /dev/tty
69.El
70.Sh SEE ALSO
71.Xr crypt 3 ,
72.Xr readpassphrase 3
73.Sh HISTORY
74A
75.Fn getpass
76function appeared in
77.At v7 .
78.Sh BUGS
79The
80.Fn getpass
81function leaves its result in an internal static object and returns
82a pointer to that object.
83Subsequent calls to
84.Fn getpass
85will modify the same object.
86.Pp
87The calling process should zero the password as soon as possible to
88avoid leaving the cleartext password visible in the process's address
89space.
90.Pp
91Upon receipt of a SIGTSTP, the input buffer will be flushed, so any
92partially typed password must be retyped when the process
93continues.
94