implement Powerman; ## Copyright © 2001 Vita Nuova Holdings Limited.  All rights reserved.# include "sys.m";	sys: Sys; include "powerman.m"; pid := 0; init(file: string, events: chan of string): int{	if(file == nil)		file = "/dev/powerdata";	fd := sys->open(file, Sys->OREAD);	if(fd == nil)		return -1;	pidc := chan of int;	spawn reader(fd, events, pidc);	return pid = <-pidc;} reader(fd: ref Sys->FD, events: chan of string, pidc: chan of int){	pidc <-= sys->pctl(0, nil);	buf := array[128] of byte;	while((n := sys->read(fd, buf, len buf)) > 0){		if(buf[n-1] == byte '\n')			n--;		events <-= string buf[0:n];	}	events <-= "error";} stop(){	if(pid != 0){		fd := sys->open("#p/"+string pid+"/ctl", Sys->OWRITE);		if(fd != nil)			sys->fprint(fd, "kill");		pid = 0;	}} ack(op: string){	ctl("ack "+op);} ctl(op: string): string{	fd := sys->open("/dev/powerctl", Sys->OWRITE);	if(fd != nil && sys->fprint(fd, "%s", op) >= 0)		return nil;	return sys->sprint("%r");}