Function zfs_check_clearable

freebsd/contrib/openzfs/module/zfs/zfs_ioctl.c:4627–4671

* Removes properties from the given props list that fail permission checks * needed to clear them and to restore them in case of a receive error. For each * property, make sure we have both set and inherit permissions. * * Returns the first error encountered if any permission checks fail. If the * caller provides a non-NULL errlist, it also gives the complete list of names * of all the prope

 * pointed at by errlist is NULL.
 */
static int
zfs_check_clearable(const char *dataset, nvlist_t *props, nvlist_t **errlist)
{
	zfs_cmd_t *zc;
	nvpair_t *pair, *next_pair;
	nvlist_t *errors;
	int err, rv = 0;

	if (props == NULL)
		return (0);

	VERIFY(nvlist_alloc(&errors, NV_UNIQUE_NAME, KM_SLEEP) == 0);

	zc = kmem_alloc(sizeof (zfs_cmd_t), KM_SLEEP);
	(void) strlcpy(zc->zc_name, dataset, sizeof (zc->zc_name));
	pair = nvlist_next_nvpair(props, NULL);
	while (pair != NULL) {
		next_pair = nvlist_next_nvpair(props, pair);

		(void) strlcpy(zc->zc_value, nvpair_name(pair),
		    sizeof (zc->zc_value));
		if ((err = zfs_check_settable(dataset, pair, CRED())) != 0 ||
		    (err = zfs_secpolicy_inherit_prop(zc, NULL, CRED())) != 0) {
			VERIFY(nvlist_remove_nvpair(props, pair) == 0);
			VERIFY(nvlist_add_int32(errors,
			    zc->zc_value, err) == 0);
		}
		pair = next_pair;
	}
	kmem_free(zc, sizeof (zfs_cmd_t));

	if ((pair = nvlist_next_nvpair(errors, NULL)) == NULL) {
		nvlist_free(errors);
		errors = NULL;
	} else {
		VERIFY(nvpair_value_int32(pair, &rv) == 0);
	}

	if (errlist == NULL)
		nvlist_free(errors);
	else
		*errlist = errors;

	return (rv);
}

static boolean_t
propval_equals(nvpair_t *p1, nvpair_t *p2)