Golang中的缓冲区问题

Question

I'm working with multi-threaded and serialized processes and want to automate my recon process.

My code works like expected, as long as i'm not calling a function called nmap. When nmap is called, it exits with the following error:

./recon-s.go:54:12: not enough arguments in call to nmap have () want (chan<- []byte)

This is my code:

package main

import (
    "fmt"
    "log"
    "os/exec"
    "sync"
)

var url string
var wg sync.WaitGroup
var ip string
func nikto(outChan chan<- []byte) {
    cmd := exec.Command("nikto", "-h", url)
    bs, err := cmd.Output()
    if err != nil {
        log.Fatal(err)
    }
    outChan <- bs
    wg.Done()
}

func whois(outChan chan<- []byte) {

    cmd := exec.Command("whois",url)
    bs, err := cmd.Output()
    if err != nil {
        log.Fatal(err)
    }
    outChan <- bs
    wg.Done()
}
func nmap (outChan chan<-[]byte) {
    fmt.Printf("Please input IP")
    fmt.Scanln(&ip)
    cmd := exec.Command("nmap","-sC","-sV","-oA","nmap",ip)
    bs,err := cmd.Output()
    if err != nil {
    log.Fatal(err)
    }
    outChan <- bs
    wg.Done()
    }
func main() {
    outChan := make(chan []byte)

    fmt.Printf("Please input URL")
    fmt.Scanln(&url)
    wg.Add(1)
    go nikto(outChan)
    wg.Add(1)
    go whois(outChan)
    wg.Add(1)
    go nmap()
    for i := 0; i < 3; i++ {
        bs := <-outChan
        fmt.Println(string(bs))
    }

    close(outChan)
    wg.Wait()
}

Answer 1

The error which one you're getting is:

not enough arguments in call to nmap have () want (chan<- []byte)

It means nmap() from main method have not any argument but the actual nmap() definition want an argument like chan<-[]byte, So you have to pass an argument from nmap() like below I mentioned the argument which one you just missed.

  func main() {
        outChan := make(chan []byte)

        fmt.Printf("Please input URL")
        fmt.Scanln(&url)
        wg.Add(1)
        go nikto(outChan)
        wg.Add(1)
        go whois(outChan) 
        wg.Add(1)
        go nmap(outChan) //you are just missing the argument here.
        for i := 0; i < 3; i++ {
            bs := <-outChan
            fmt.Println(string(bs))
        }

        close(outChan)
        wg.Wait()
    }