GoPass/main.go

95 lines
2.5 KiB
Go

// GoPass
// Author: Maximilian Patterson
package main
import (
"crypto/rand"
"fmt"
"math/big"
"os"
"strconv"
"strings"
)
var allowedCharacters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890`~!@#$%^&*()_+[]\\{}|;':,./<>?")
const (
Version = "1.3.0"
symbols = "`~!@#$%^&*()_+[]\\{}|;':,./<>?"
)
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
err := error(nil)
if size, err = strconv.Atoi(args[0]); err == nil { // If first argument is an integer
} else if args[0] == "-v" {
return "GoPass version " + Version
} else if args[0] == "-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"
}
for i := 1; i < len(args); i++ {
v := args[i]
if v == "-s" {
removeDisallowed([]rune(symbols))
} else if strings.HasPrefix(v, "-r=") { // If argument starts with -r=
// Remove all characters after the = until next whitespace
removeDisallowed([]rune(v[2:]))
} else {
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) {
for _, r := range disallowed {
for i, v := range allowedCharacters {
if v == r {
allowedCharacters = append(allowedCharacters[:i], allowedCharacters[i+1:]...)
}
}
}
}
func generatePassword(size int) string {
// Make empty array of runes with size of size
pass := make([]rune, size)
// Assign every slot of pass to a random allowedCharacter
for i := range pass {
// Generate a random int greater than 0 and not to exceed the length of allowedCharacters
index, err := rand.Int(rand.Reader, big.NewInt(int64(len(allowedCharacters))))
if err != nil {
println("Error securely generating random character!")
return ""
}
pass[i] = allowedCharacters[index.Int64()]
}
return string(pass)
}
func main() {
// Process arguments
fmt.Println(matchArguments(os.Args[1:]))
}