1// Copyright 2015 CoreOS, Inc. 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15// Package activation implements primitives for systemd socket activation. 16package activation 17 18import ( 19 "os" 20 "strconv" 21 "syscall" 22) 23 24// based on: https://gist.github.com/alberts/4640792 25const ( 26 listenFdsStart = 3 27) 28 29func Files(unsetEnv bool) []*os.File { 30 if unsetEnv { 31 defer os.Unsetenv("LISTEN_PID") 32 defer os.Unsetenv("LISTEN_FDS") 33 } 34 35 pid, err := strconv.Atoi(os.Getenv("LISTEN_PID")) 36 if err != nil || pid != os.Getpid() { 37 return nil 38 } 39 40 nfds, err := strconv.Atoi(os.Getenv("LISTEN_FDS")) 41 if err != nil || nfds == 0 { 42 return nil 43 } 44 45 files := make([]*os.File, 0, nfds) 46 for fd := listenFdsStart; fd < listenFdsStart+nfds; fd++ { 47 syscall.CloseOnExec(fd) 48 files = append(files, os.NewFile(uintptr(fd), "LISTEN_FD_"+strconv.Itoa(fd))) 49 } 50 51 return files 52} 53