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READPASSPHRASE(3) | Library Functions Manual | READPASSPHRASE(3) |
NAME¶
readpassphrase — get a passphrase from the userLIBRARY¶
library “libbsd”SYNOPSIS¶
#include <bsd/readpassphrase.h> 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.
readpassphrase() takes the following optional
flags:
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 force read of passphrase from stdin
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"); ... memset(passbuf, 0, 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.May 31, 2007 | Debian |