FIDO_DEV_INFO_MANIFEST(3) | Library Functions Manual | FIDO_DEV_INFO_MANIFEST(3)

# NAME

`fido_dev_info_manifest`, `fido_dev_info_new`, `fido_dev_info_free`, `fido_dev_info_ptr`, `fido_dev_info_path`, `fido_dev_info_product`, `fido_dev_info_vendor`, `fido_dev_info_manufacturer_string`, `fido_dev_info_product_string`, `fido_dev_info_set` — FIDO2 device discovery functions

# SYNOPSIS

library “libfido2” libcbor libcrypto libz
`#include <fido.h>`

int
`fido_dev_info_manifest`(fido_dev_info_t *devlist, size_t ilen, size_t *olen);

fido_dev_info_t *
`fido_dev_info_new`(size_t n);

void
`fido_dev_info_free`(fido_dev_info_t **devlist_p, size_t n);

const fido_dev_info_t *
`fido_dev_info_ptr`(const fido_dev_info_t *devlist, size_t i);

const char *
`fido_dev_info_path`(const fido_dev_info_t *di);

int16_t
`fido_dev_info_product`(const fido_dev_info_t *di);

int16_t
`fido_dev_info_vendor`(const fido_dev_info_t *di);

const char *
`fido_dev_info_manufacturer_string`(const fido_dev_info_t *di);

const char *
`fido_dev_info_product_string`(const fido_dev_info_t *di);

int
`fido_dev_info_set`(fido_dev_info_t *devlist, size_t i, const char *path, const char *manufacturer, const char *product, const fido_dev_io_t *io, const fido_dev_transport_t *transport);

# DESCRIPTION

The `fido_dev_info_manifest`() function fills devlist with up to ilen FIDO2 devices found by the underlying operating system. Currently only USB HID devices are supported. The number of discovered devices is returned in olen, where olen is an addressable pointer.

The `fido_dev_info_new`() function returns a pointer to a newly allocated, empty device list with n available slots. If memory is not available, NULL is returned.

The `fido_dev_info_free`() function releases the memory backing *devlist_p, where *devlist_p must have been previously allocated by `fido_dev_info_new`(). The number n of allocated slots must also be provided. On return, *devlist_p is set to NULL. Either devlist_p or *devlist_p may be NULL, in which case `fido_dev_info_free`() is a NOP.

The `fido_dev_info_ptr`() function returns a pointer to slot number i of devlist. It is the caller's responsibility to ensure that i is bounded. Please note that the first slot has index 0.

The `fido_dev_info_path`() function returns the filesystem path or subsystem-specific identification string of di.

The `fido_dev_info_product`() function returns the product ID of di.

The `fido_dev_info_vendor`() function returns the vendor ID of di.

The `fido_dev_info_manufacturer_string`() function returns the manufacturer string of di. If di does not have an associated manufacturer string, `fido_dev_info_manufacturer_string`() returns an empty string.

The `fido_dev_info_product_string`() function returns the product string of di. If di does not have an associated product string, `fido_dev_info_product_string`() returns an empty string.

An example of how to use the functions described in this document can be found in the examples/manifest.c file shipped with libfido2.

The `fido_dev_info_set`() function initializes an entry in a device list allocated by `fido_dev_info_new`() with the specified path, manufacturer, and product strings, and with the specified I/O handlers and, optionally, transport functions, as described in fido_dev_set_io_functions(3). The io argument must be specified; the transport argument may be `NULL`. The path, I/O handlers, and transport functions will be used automatically by fido_dev_new_with_info(3) and fido_dev_open_with_info(3). An application can use this, for example, to substitute mock FIDO2 devices in testing for the real ones that `fido_dev_info_manifest`() would discover.

# RETURN VALUES

The `fido_dev_info_manifest`() function always returns `FIDO_OK`. If a discovery error occurs, the olen pointer is set to 0.

On success, the `fido_dev_info_set`() function returns `FIDO_OK`. On error, a different error code defined in `<fido/err.h>` is returned.

The pointers returned by `fido_dev_info_ptr`(), `fido_dev_info_path`(), `fido_dev_info_manufacturer_string`(), and `fido_dev_info_product_string`() are guaranteed to exist until `fido_dev_info_free`() is called on the corresponding device list.

July 9, 2025 | Debian