NAME

     fido_dev_set_pin, fido_dev_get_retry_count, fido_dev_get_uv_retry_count, fido_dev_reset —
     FIDO2 device management functions

SYNOPSIS

     #include <fido.h>

     int
     fido_dev_set_pin(fido_dev_t *dev, const char *pin, const char *oldpin);

     int
     fido_dev_get_retry_count(fido_dev_t *dev, int *retries);

     int
     fido_dev_get_uv_retry_count(fido_dev_t *dev, int *retries);

     int
     fido_dev_reset(fido_dev_t *dev);

DESCRIPTION

     The fido_dev_set_pin() function sets the PIN of device dev to pin, where pin is a NUL-
     terminated UTF-8 string.  If oldpin is not NULL, the device's PIN is changed from oldpin to
     pin, where pin and oldpin are NUL-terminated UTF-8 strings.

     The fido_dev_get_retry_count() function fills retries with the number of PIN retries left in
     dev before lock-out, where retries is an addressable pointer.

     The fido_dev_get_uv_retry_count() function fills retries with the number of built-in UV
     retries left in dev before built-in UV is disabled, where retries is an addressable pointer.

     The fido_dev_reset() function performs a reset on dev, resetting the device's PIN and
     erasing credentials stored on the device.

     Please note that fido_dev_set_pin(), fido_dev_get_retry_count(),
     fido_dev_get_uv_retry_count(), and fido_dev_reset() are synchronous and will block if
     necessary.

RETURN VALUES

     The error codes returned by fido_dev_set_pin(), fido_dev_get_retry_count(),
     fido_dev_get_uv_retry_count(), and fido_dev_reset() are defined in <fido/err.h>.  On
     success, FIDO_OK is returned.

CAVEATS

     Regarding fido_dev_reset(), the actual user-flow to perform a reset is outside the scope of
     the FIDO2 specification, and may therefore vary depending on the authenticator.  Yubico
     authenticators will return FIDO_ERR_NOT_ALLOWED if a reset is issued later than 5 seconds
     after power-up, and FIDO_ERR_ACTION_TIMEOUT if the user fails to confirm the reset by
     touching the key within 30 seconds.