// attempt to broadcast msg to all lines registered in utmp
// returns count of lines successfully opened (and likely broadcasted to)
func broadcast(msg string) uint {
var cnt uint
C.setutent()
for {
var utmp *C.struct_utmp
utmp = C.getutent()
if utmp == nil {
break
}
line := C.GoString(&utmp.ut_line[0])
tty, _ := os.OpenFile("/dev/"+line, os.O_WRONLY, 0)
if tty == nil {
// ignore errors, this is just a best-effort courtesy notice
continue
}
cnt++
go func() {
fmt.Fprintf(tty, "\r%79s\r\n", " ")
fmt.Fprintf(tty, "%-79.79s\007\007\r\n", fmt.Sprintf("Broadcast message from locksmithd at %s:", time.Now()))
fmt.Fprintf(tty, "%-79.79s\r\n", msg) // msg is assumed to be short and not require wrapping
fmt.Fprintf(tty, "\r%79s\r\n", " ")
tty.Close()
}()
}
return cnt
}
func main() {
var p_utent *C.utmp
C.getutent()
fmt.Println(p_utent.ut_user)
}