FIDO\_DEV\_SET\_PIN(3) Library Functions Manual FIDO\_DEV\_SET\_PIN(3)

# [NAME](#NAME)

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

# [SYNOPSIS](#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](#DESCRIPTION)

The [`fido_dev_set_pin`](#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`](#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`](#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`](#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_set_pin~2)(), `fido_dev_get_retry_count`(), `fido_dev_get_uv_retry_count`(), and `fido_dev_reset`() are synchronous and will block if necessary.

# [RETURN VALUES](#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.

# [SEE ALSO](#SEE_ALSO)

[fido\_cbor\_info\_uv\_attempts(3)](/man/os/libfido2/fido_cbor_info_uv_attempts.3)

# [CAVEATS](#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.

May 25, 2018 Linux 4.19.0-gvisor

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Document: fido_dev_get_uv_retry_count(3) from libfido2 1.17.0-r7 (Chainguard OS)
Source: https://github.com/Yubico/libfido2