src/pacman/pacman.c:778:	uid_t myuid = geteuid();
src/pacman/pacman.c:908:	if(myuid > 0 && needs_root()){
				pm_printf(ALPM_LOG_ERROR, _("you cannot perform this operation unless you are root\n")); 
				cleanup(EXIT_FAILURE);
				};

src/pacman/util.c:95
int needs_root(void)
{
	switch(config->op) {
		case PM_OP_DATABASE:
			return 1;
		case PM_OP_UPGRADE:
		case PM_OP_REMOVE:
			return !config->print;
		case PM_OP_SYNC:
			return (config->op_s_clean || config->op_s_sync ||
					(!config->group && !config->op_s_info && !config->op_q_list &&
					 !config->op_s_search && !config->print));
		default:
			return 0;
	}
}