Why "RegisterInterruptHandler is a no-op on windows" #16768

Equationzhao · 2023-10-16T15:09:07Z

Equationzhao
Oct 16, 2023

in the interrupt_windows.go, the RegisterInterruptHandler and HandleInterrupts are empty.

but the UNIX one listens to the int and term signals and does something to kill those process

Why?

windows

package osutil

import (
	"os"

	"go.uber.org/zap"
)

type InterruptHandler func()

// RegisterInterruptHandler is a no-op on windows
func RegisterInterruptHandler(h InterruptHandler) {}

// HandleInterrupts is a no-op on windows
func HandleInterrupts(*zap.Logger) {}

// Exit calls os.Exit
func Exit(code int) {
	os.Exit(code)
}

unix

// RegisterInterruptHandler registers a new InterruptHandler. Handlers registered
// after interrupt handing was initiated will not be executed.
func RegisterInterruptHandler(h InterruptHandler) {
	interruptRegisterMu.Lock()
	defer interruptRegisterMu.Unlock()
	interruptHandlers = append(interruptHandlers, h)
}

// HandleInterrupts calls the handler functions on receiving a SIGINT or SIGTERM.
func HandleInterrupts(lg *zap.Logger) {
	verify.Assert(lg != nil, "the logger should not be nil")
	notifier := make(chan os.Signal, 1)
	signal.Notify(notifier, syscall.SIGINT, syscall.SIGTERM)

	go func() {
		sig := <-notifier

		interruptRegisterMu.Lock()
		ihs := make([]InterruptHandler, len(interruptHandlers))
		copy(ihs, interruptHandlers)
		interruptRegisterMu.Unlock()

		interruptExitMu.Lock()

		lg.Info("received signal; shutting down", zap.String("signal", sig.String()))

		for _, h := range ihs {
			h()
		}
		signal.Stop(notifier)
		pid := syscall.Getpid()
		// exit directly if it is the "init" process, since the kernel will not help to kill pid 1.
		if pid == 1 {
			os.Exit(0)
		}
		setDflSignal(sig.(syscall.Signal))
		syscall.Kill(pid, sig.(syscall.Signal))
	}()
}

// Exit relays to os.Exit if no interrupt handlers are running, blocks otherwise.
func Exit(code int) {
	interruptExitMu.Lock()
	os.Exit(code)
}