Section: C Library Functions (3)Index
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- get a passphrase from the user
Fd #include <bsd/readpassphrase.h
Ft char *
Fn readpassphrase const char *prompt char *buf size_t bufsiz int flags
function displays a prompt to, and reads in a passphrase from,
If this file is inaccessible
flag is not set,
displays the prompt on the standard error output and reads from the standard
In this case it is generally not possible to turn off echo.
- 1 characters (one is for the NUL) are read into the provided buffer
Fa buf .
characters and the terminating newline (or return) character are discarded.
takes the following optional
Fa 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
The calling process should zero the passphrase as soon as possible to
avoid leaving the cleartext passphrase visible in the process's address
Upon successful completion,
returns a pointer to the NUL-terminated passphrase.
If an error is encountered, the terminal state is restored and
a null pointer is returned.
The following code fragment will read a passphrase from
into the buffer
Fa passbuf .
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));
- Bq Er EINTR
function was interrupted by a signal.
- Bq Er EINVAL
argument was zero.
- Bq Er EIO
The process is a member of a background process attempting to read
from its controlling terminal, the process is ignoring or blocking
signal, or the process group is orphaned.
- Bq Er EMFILE
The process has already reached its limit for open file descriptors.
- Bq Er ENFILE
The system file table is full.
- Bq Er ENOTTY
There is no controlling terminal and the
flag was specified.
will catch the following signals:
SIGALRM SIGHUP SIGINT
SIGPIPE SIGQUIT SIGTERM
SIGTSTP SIGTTIN SIGTTOU
When one of the above signals is intercepted, terminal echo will
be restored if it had previously been turned off.
If a signal handler was installed for the signal when
was called, that handler is then executed.
If no handler was previously installed for the signal then the
default action is taken as per
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,
will reprint the prompt and the user may then enter a passphrase.
function is an
Ox extension and should not be used if portability is desired.
function first appeared in
Ox 2.9 .
- RETURN VALUES
- SEE ALSO