NAME
readpassphrase — get a passphrase from the userLIBRARY
library “libbsd”SYNOPSIS
#include <readpassphrase.h> (See libbsd(7) for include usage.)char *
readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags);
DESCRIPTION
The readpassphrase() function displays a prompt to, and reads in a passphrase from, /dev/tty. If this file is inaccessible and theRPP_REQUIRE_TTY
flag is not set,
readpassphrase() displays the prompt on the
standard error output and reads from the standard input. In this case it is
generally not possible to turn off echo.
Up to bufsiz - 1 characters (one is for the
NUL) are read into the provided buffer buf.
Any additional characters and the terminating newline (or return) character
are discarded.
The flags argument is the bitwise OR of zero or
more of the following values:
RPP_ECHO_OFF turn off echo (default behavior) RPP_ECHO_ON leave echo on RPP_REQUIRE_TTY fail if there is no tty RPP_FORCELOWER force input to lower case RPP_FORCEUPPER force input to upper case RPP_SEVENBIT strip the high bit from input RPP_STDIN read passphrase from stdin; ignore prompt
RETURN VALUES
Upon successful completion, readpassphrase() returns a pointer to the NUL-terminated passphrase. If an error is encountered, the terminal state is restored and a null pointer is returned.FILES
- /dev/tty
EXAMPLES
The following code fragment will read a passphrase from /dev/tty into the buffer passbuf.char passbuf[1024]; ... if (readpassphrase("Response: ", passbuf, sizeof(passbuf), RPP_REQUIRE_TTY) == NULL) errx(1, "unable to read passphrase"); if (compare(transform(passbuf), epass) != 0) errx(1, "bad passphrase"); ... explicit_bzero(passbuf, sizeof(passbuf));
ERRORS
- [
EINTR
] - The readpassphrase() function was interrupted by a signal.
- [
EINVAL
] - The bufsiz argument was zero.
- [
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.
- [
ENFILE
] - The system file table is full.
- [
ENOTTY
] - There is no controlling terminal and the
RPP_REQUIRE_TTY
flag was specified.
SIGNALS
readpassphrase() will catch the following signals:SIGALRM SIGHUP SIGINT SIGPIPE SIGQUIT SIGTERM SIGTSTP SIGTTIN SIGTTOU
SIGTSTP
,
SIGTTIN
, and
SIGTTOU
signals (stop signals generated
from keyboard or due to terminal I/O from a background process) are treated
specially. When the process is resumed after it has been stopped,
readpassphrase() will reprint the prompt and the
user may then enter a passphrase.
SEE ALSO
sigaction(2), getpass(3)STANDARDS
The readpassphrase() function is an OpenBSD extension and should not be used if portability is desired.HISTORY
The readpassphrase() function first appeared in OpenBSD 2.9.March 6, 2014 | Debian |