The
getpass();
function displays a prompt to, and reads in a password from,
/dev/tty.
If this file is not accessible,
getpass();
displays the prompt on the standard error output and reads from the standard
input.
The password may be up to
_PASSWORD_LEN
(currently 128, as defined in the
‹pwd.h›
include file)
characters in length.
Any additional
characters and the terminating newline character are discarded.
getpass();
turns off character echoing while reading the password.
The calling process should zero the password as soon as possible to
avoid leaving the cleartext password visible in the process's address
space.
RETURN VALUES
Upon successful completion,
getpass();
returns a pointer to a NUL-terminated string of at most
_PASSWORD_LEN
characters.
If an error is encountered, the terminal state is restored and
a null pointer is returned.
FILES
/dev/tty
ERRORS
[EINTR]
The
getpass();
function was interrupted by a signal.
[EIO]
The process is a member of a background process attempting to read
from its controlling terminal, the process is ignoring or blocking
the SIGTTIN signal or the process group is orphaned.
[EMFILE]
The process has already reached its limit for open file descriptors.
Historically,
BSD
versions of
getpass();
have accepted a password on the standard input if
/dev/tty
is unavailable.
This contradicts
but the
OpenBSD
implementation is conformant in all other respects.
HISTORY
A
getpass();
function appeared in
Version 7 AT&T UNIX.
BUGS
The
getpass();
function leaves its result in an internal static object and returns
a pointer to that object.
Subsequent calls to
getpass();
will modify the same object.