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缘由：

以后可能要用Golang语言写一个daemon程序（守护进程）运行在服务器上，以进行一些信息收集的工作。之前只是简单知道什么是守护进程，但对于一些细节以及该如何用Golang进行编写都不太清楚，所以需要先学习、准备一下。

正文：

参考解答：

……待补充……

package main

import (
    "fmt"
    "log"
    "os"
    "os/signal"
    "runtime"
    "syscall"
    "time"
)

func daemon(nochdir, noclose int) int {
    var ret, ret2 uintptr
    var err syscall.Errno
    darwin := runtime.GOOS == "darwin"
    // already a daemon
    if syscall.Getppid() == 1 {
        return 0
    }
    // fork off the parent process
    ret, ret2, err = syscall.RawSyscall(syscall.SYS_FORK, 0, 0, 0)
    if err != 0 {
        return -1
    }
    // failure
    if ret2 < 0 {
        os.Exit(-1)
    }
    // handle exception for darwin
    if darwin && ret2 == 1 {
        ret = 0
    }
    // if we got a good PID, then we call exit the parent process.
    if ret > 0 {
        os.Exit(0)
    }
    /* Change the file mode mask */
    _ = syscall.Umask(0)

    // create a new SID for the child process
    s_ret, s_errno := syscall.Setsid()
    if s_errno != nil {
        log.Printf("Error: syscall.Setsid errno: %d", s_errno)
    }
    if s_ret < 0 {
        return -1
    }
    if nochdir == 0 {
        os.Chdir("/")
    }
    if noclose == 0 {
        f, e := os.OpenFile("/dev/null", os.O_RDWR, 0)
        if e == nil {
            fd := f.Fd()
            syscall.Dup2(int(fd), int(os.Stdin.Fd()))
            syscall.Dup2(int(fd), int(os.Stdout.Fd()))
            syscall.Dup2(int(fd), int(os.Stderr.Fd()))
        }
    }
    return 0
}

func main() {
    daemon(0, 1)
    for {
        fmt.Println("hello")
        time.Sleep(1 * time.Second)
    }
}

……待补充……

参考链接：

• Go到目前还没有解决成为守护进程(Daemonize)的问题吧？各位是怎么解决的？
  https://segmentfault.com/q/1010000000699471
• Golang创建daemon程序
  http://shanks.leanote.com/post/Go%E5%88%9B%E5%BB%BAdaemon%E7%A8%8B%E5%BA%8F
• Go语言daemon启动的解决方法.linux平台
  http://blog.csdn.net/fyxichen/article/details/50541449
• How to create a daemon process in Golang?
  http://stackoverflow.com/questions/23736046/how-to-create-a-daemon-process-in-golang
• https://github.com/sevlyar/go-daemon
  https://github.com/takama/daemon
  https://github.com/VividCortex/godaemon
  https://github.com/fiorix/go-daemon
• =
• How do I get my Golang web server to run in the background?
  http://stackoverflow.com/questions/12486691/how-do-i-get-my-golang-web-server-to-run-in-the-background
• supervisor运行golang守护进程
  http://www.01happy.com/supervisor-golang-daemon/
• 用golang启动一个daemon
  http://www.cnblogs.com/toby/p/3262516.html

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