Function ExecCheckRTEPermsModified

src/backend/executor/execMain.c:1599–1635

* ExecCheckRTEPermsModified * Check INSERT or UPDATE access permissions for a single RTE (these * are processed uniformly). */

 *		are processed uniformly).
 */
static bool
ExecCheckRTEPermsModified(Oid relOid, Oid userid, Bitmapset *modifiedCols,
						  AclMode requiredPerms)
{
	int			col = -1;

	/*
	 * When the query doesn't explicitly update any columns, allow the query
	 * if we have permission on any column of the rel.  This is to handle
	 * SELECT FOR UPDATE as well as possible corner cases in UPDATE.
	 */
	if (bms_is_empty(modifiedCols))
	{
		if (pg_attribute_aclcheck_all(relOid, userid, requiredPerms,
									  ACLMASK_ANY) != ACLCHECK_OK)
			return false;
	}

	while ((col = bms_next_member(modifiedCols, col)) >= 0)
	{
		/* bit #s are offset by FirstLowInvalidHeapAttributeNumber */
		AttrNumber	attno = col + FirstLowInvalidHeapAttributeNumber;

		if (attno == InvalidAttrNumber)
		{
			/* whole-row reference can't happen here */
			elog(ERROR, "whole-row update is not implemented");
		}
		else
		{
			if (pg_attribute_aclcheck(relOid, attno, userid,
									  requiredPerms) != ACLCHECK_OK)
				return false;
		}
	}
	return true;
}

/*
 * Check that the query does not imply any writes to non-temp tables;