| // 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. |
| |
| // +build !windows,!plan9 |
| |
| package osutil |
| |
| import ( |
| "os" |
| "os/signal" |
| "sync" |
| "syscall" |
| ) |
| |
| // 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() { |
| 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() |
| |
| plog.Noticef("received %v signal, shutting down...", sig) |
| |
| 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) |
| } |