libfreefare/examples/ntag-detect.c

#include <err.h>
#include <stdlib.h>

#include <nfc/nfc.h>

#include <freefare.h>

int
main(int argc, char *argv[])
{
    int error = EXIT_SUCCESS;
    nfc_device *device = NULL;
    FreefareTag *tags = NULL;

    if (argc > 1)
	errx(EXIT_FAILURE, "usage: %s", argv[0]);

    nfc_connstring devices[8];
    size_t device_count;

    nfc_context *context;
    nfc_init(&context);
    if (context == NULL)
	errx(EXIT_FAILURE, "Unable to init libnfc (malloc)");

    device_count = nfc_list_devices(context, devices, sizeof(devices) / sizeof(*devices));
    if (device_count <= 0)
	errx(EXIT_FAILURE, "No NFC device found");

    for (size_t d = 0; d < device_count; d++) {
	if (!(device = nfc_open(context, devices[d]))) {
	    warnx("nfc_open() failed.");
	    error = EXIT_FAILURE;
	    continue;
	}

	if (!(tags = freefare_get_tags(device))) {
	    nfc_close(device);
	    errx(EXIT_FAILURE, "Error listing tags.");
	}

	for (int i = 0; (!error) && tags[i]; i++) {
	    char *tag_uid = freefare_get_tag_uid(tags[i]);
	    printf("Tag with UID %s is a %s\n", tag_uid, freefare_get_tag_friendly_name(tags[i]));
	    free(tag_uid);
	}
	freefare_free_tags(tags);
	nfc_close(device);
    }
    nfc_exit(context);
    exit(error);
}