evil cat

evilcat.go

package main

import (
	"io"
	"log"
	"os"
	"strings"
)

func readWrite(src io.Reader, dst io.Writer) {
}

func errorhandler(err error, fname string) {

	if _, ok := err.(*os.PathError); ok {
		log.Fatal("cat: " + fname + ": No such file or directory")
	} else {
		// also includes our lies.
		log.Fatal("cat: " + fname + ": Permission denied")
	}
}

func main() {
	log.SetFlags(0)
	if len(os.Args) == 1 {
		_, err := io.Copy(os.Stdout, os.Stdin)
		if err != nil {
			log.Fatal(err)
		}
	} else {
		for _, fname := range os.Args[1:] {
			if !(strings.Contains(fname, "flag") || strings.Contains(fname, "king.txt") || strings.Contains(fname, "user")) {
				fh, err := os.Open(fname)
				if err != nil {
					errorhandler(err, fname)
				}

				_, err = io.Copy(os.Stdout, fh)
				if err != nil {
					errorhandler(err, fname)
				}
			} else {
				errorhandler(nil, fname) // we are lieing
			}

		}
	}
}