GoPass/main.go

132 lines
3.2 KiB
Go

// GoPass
// Author: Maximilian Patterson
package main
import (
"crypto/rand"
"fmt"
"math/big"
"os"
"runtime"
"strconv"
"strings"
)
var allowedCharacters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890`~!@#$%^&*()_+[]\\{}|;':,./<>?")
const (
Version = "1.3.1"
symbols = "`~!@#$%^&*()_+[]\\{}|;':,./<>?"
chunkSize = 16 // The size of each chunk of the password to be generated by the worker goroutines
)
func matchArguments(args []string) string {
// If there are no arguments
if len(args) == 0 {
return "No password length specified! (ex: gopass 16)"
}
// First argument is special, must be an integer, -v, or -h
var size = 0 // Password length
switch args[0] {
case "-v":
return "GoPass version " + Version
case "-h":
return "GoPass - A simple password generator written in Go\n" +
"Usage: gopass [length] [disallowed characters] [optional remove symbols -s]\n" +
" Example: gopass 16\n" +
" Example: gopass 16 -r=abc123!@#\n" +
" Example: gopass 16 -s\n" +
"\nFor help (this output): gopass -h\n" +
"For version: gopass -v\n"
default:
err := error(nil)
size, err = strconv.Atoi(args[0])
if err != nil {
return "Invalid first argument (\"" + args[0] + "\") supplied! (Type gopass -h for help)"
}
}
for i := 1; i < len(args); i++ {
v := args[i]
switch {
case v == "-s":
removeDisallowed([]rune(symbols))
case strings.HasPrefix(v, "-r="):
// Remove all characters after the = until next whitespace
removeDisallowed([]rune(v[2:]))
default:
return "Invalid argument (\"" + v + "\") supplied! (Type gopass -h for help)"
}
}
if size <= 0 {
return "No/invalid password length specified! (ex: gopass 16)"
} else {
return generatePassword(size)
}
}
// Remove all disallowed characters from the allowedCharacters slice
func removeDisallowed(disallowed []rune) {
disallowedMap := make(map[rune]bool, len(disallowed))
for _, r := range disallowed {
disallowedMap[r] = true
}
i := 0
for _, v := range allowedCharacters {
if !disallowedMap[v] {
allowedCharacters[i] = v
i++
}
}
allowedCharacters = allowedCharacters[:i]
}
func generatePassword(size int) string {
// Make empty array of runes with size of size
pass := make([]rune, size)
// Create a channel to receive chunks of the password
passChan := make(chan []rune)
// Determine the number of worker goroutines to use
numWorkers := runtime.NumCPU()
// Launch the worker goroutines
for i := 0; i < numWorkers; i++ {
go func() {
allowedLen := len(allowedCharacters)
for {
// Generate a chunk of the password
chunk := make([]rune, chunkSize)
for i := range chunk {
index, err := rand.Int(rand.Reader, big.NewInt(int64(allowedLen)))
if err != nil {
println("Error securely generating random character chunk!")
return
}
chunk[i] = allowedCharacters[index.Int64()]
}
// Send the chunk of the password to the main goroutine
passChan <- chunk
}
}()
}
// Collect the chunks of the password from the channel
for i := 0; i < size; i += chunkSize {
chunk := <-passChan
copy(pass[i:], chunk)
}
return string(pass)
}
func main() {
// Process arguments
fmt.Println(matchArguments(os.Args[1:]))
}