xref: /freebsd/lib/libc/gen/getpass.3 (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
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28.Dd June 4, 1993
29.Dt GETPASS 3
30.Os
31.Sh NAME
32.Nm getpass
33.Nd get a password
34.Sh LIBRARY
35.Lb libc
36.Sh SYNOPSIS
37.In pwd.h
38.In unistd.h
39.Ft char *
40.Fn getpass "const char *prompt"
41.Sh DESCRIPTION
42The
43.Fn getpass
44function displays a prompt to, and reads in a password from,
45.Pa /dev/tty .
46If this file is not accessible,
47.Fn getpass
48displays the prompt on the standard error output and reads from the standard
49input.
50.Pp
51The password may be up to _PASSWORD_LEN (currently 128)
52characters in length.
53Any additional
54characters and the terminating newline character are discarded.
55.Pp
56The
57.Fn getpass
58function turns off character echoing while reading the password.
59.Sh RETURN VALUES
60The
61.Fn getpass
62function returns a pointer to the null terminated password.
63.Sh FILES
64.Bl -tag -width /dev/tty -compact
65.It Pa /dev/tty
66.El
67.Sh SEE ALSO
68.Xr crypt 3 ,
69.Xr readpassphrase 3
70.Sh HISTORY
71A
72.Fn getpass
73function appeared in
74.At v7 .
75.Sh BUGS
76The
77.Fn getpass
78function leaves its result in an internal static object and returns
79a pointer to that object.
80Subsequent calls to
81.Fn getpass
82will modify the same object.
83.Pp
84The calling process should zero the password as soon as possible to
85avoid leaving the cleartext password visible in the process's address
86space.
87.Pp
88Upon receipt of a SIGTSTP, the input buffer will be flushed, so any
89partially typed password must be retyped when the process
90continues.
91