ref: 8a788aea84aad3bfbd5b39d78c1925654f3b9e14
dir: /appl/svc/httpd/alarms.b/
implement Alarms; include "sys.m"; sys: Sys; include "alarms.m"; Alarm.stop(a: self Alarm) { a.alchan <-= -1; fd:=sys->open("#p/"+string a.pid+"/ctl",sys->OWRITE); sys->fprint(fd, "killgrp"); } Alarm.alarm(time: int): Alarm { if (sys == nil) sys = load Sys Sys->PATH; pid := sys->pctl(sys->NEWPGRP|sys->FORKNS,nil); a:=Alarm(chan of int,pid); spawn listener(a.alchan); spawn sleeper(a.alchan,time,pid); return a; } sleeper(ch: chan of int, time, pid: int) { sys->sleep(time); alt{ ch <-= pid => ; * => exit; } } listener(ch: chan of int) { a := <-ch; if (a==-1) exit; fd := sys->open("#p/"+string a+"/ctl",sys->OWRITE); if (fd != nil) sys->fprint(fd, "killgrp"); }