processmonitor.go

package main

import (
	"bufio"
	"bytes"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"strconv"
	"time"
)

func main() {
	path := flag.String("b", "", "binary path")
	flag.Parse()
	cmd := exec.Command(*path)
	if err := cmd.Start(); err != nil {
		log.Fatal(err)
	}

	pid := cmd.Process.Pid
	out, err := ps(pid)
	if err != nil {
		log.Fatal(err)
	}
	defer cmd.Process.Kill()
	fmt.Println(string(out))

	knownPids := map[int]bool{}

	for {
		ints, _ := pgrep(pid)
		for _, i := range ints {
			if knownPids[i] {
				continue
			}
			out, err := ps(i)
			if err != nil {
				log.Fatal(err)
			}
			fmt.Println(string(out))
			knownPids[i] = true
		}
		time.Sleep(1 * time.Second)
	}

	time.Sleep(60 * time.Second)

}

func ps(pid int) ([]byte, error) {
	out, err := exec.Command("ps", "-p", fmt.Sprintf("%d", pid)).CombinedOutput()
	return out, err
}

func pgrep(pid int) ([]int, error) {
	cmd := exec.Command("pgrep", "-P", fmt.Sprintf("%d", pid))
	cmd.Stderr = os.Stderr
	out, err := cmd.Output()
	if err != nil {
		return nil, err
	}
	var ints []int
	r := bufio.NewReader(bytes.NewReader(out))
	for {
		line, _, err := r.ReadLine()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, err
		}
		if i, err := strconv.Atoi(string(line)); err == nil {
			ints = append(ints, i)
		}
	}
	return ints, err
}