Function feature_present

tools/compat/feature_present.c:51–69

* Returns true if the named feature is present in the currently * running kernel. A feature's presence is indicated by an integer * sysctl node called kern.feature. that is non-zero. */

 * sysctl node called kern.feature.<feature> that is non-zero.
 */
int
feature_present(const char *feature)
{
	char *mib;
	size_t len;
	int i;

	if (asprintf(&mib, "kern.features.%s", feature) < 0)
		return (0);
	len = sizeof(i);
	if (sysctlbyname(mib, &i, &len, NULL, 0) < 0) {
		free(mib);
		return (0);
	}
	free(mib);
	if (len != sizeof(i))
		return (0);
	return (i != 0);
}