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// Copyright 2015 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build !windows && !plan9
// +build !windows,!plan9
package osutil
import (
"os"
"os/signal"
"sync"
"syscall"
"go.uber.org/zap"
)
// InterruptHandler is a function that is called on receiving a
// SIGTERM or SIGINT signal.
type InterruptHandler func()
var (
interruptRegisterMu, interruptExitMu sync.Mutex
// interruptHandlers holds all registered InterruptHandlers in order
// they will be executed.
interruptHandlers = []InterruptHandler{}
)
// 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) {
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()
if lg != nil {
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)
}
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