Redid makepass.bash

Without any polish...

But makepass.bash is now about 5.5x faster than previously!

1 files changed, 243 insertions, 31 deletions

diff --git a/makepass.bash b/makepass.bash
index c2edf82..16dffa9 100755
--- a/makepass.bash
+++ b/makepass.bash
@@ -5,52 +5,264 @@
 # Bug-Reports:   Email <git@dnns.no>
 # License:       This file is licensed under the BSD 3-Clause license.
 ################################################################################
-# This file takes randomness from /dev/urandom and turns it into random
-# passwords.
+# This script generates random passwords.
 ################################################################################
+# Copyright (c) 2018-2023 Dennis Eriksen • d@ennis.no
 
+MAX=255         # max length of passwords
+RANGE_MAX=42    # max length when using random length
+RANGE_MIN=8     # min length when using random length
+PASS_WORDS=8    # number of words in passphrases
 
-# Copyright (c) 2018-2023 Dennis Eriksen • d@ennis.no
+LOWER='abcdefghijklmnopqrstuvwxyz'
+UPPER='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+DIGIT='0123456789'
+OTHER='!#$%&/()=?+-_,.;:<>[]{}|@*'
+ALPHA=${LOWER}${UPPER}
+ALNUM=${ALPHA}${DIGIT}
+EVERY=${ALNUM}${OTHER}
+
+LENGTH=${MAKEPASS_LENGTH:-0}     # length of passwords. 0 means "random number between RANGE_MIN and RANGE_MAX"
+NUMBER=${MAKEPASS_NUMBER:-10}    # number of passwords
+PRINTLEN=${MAKEPASS_PRINTLEN:-0} # print length of passwords
+NORMAL=${MAKEPASS_NORMAL:-$ALNUM'-_'}
+SPECIAL=${MAKEPASS_SPECIAL:-$EVERY}
+WORDLIST=${MAKEPASS_WORDLIST:-/usr/share/dict/words}
+XWIDTH=$(tput cols)
+WORDS=()
+
+#
+# Functions
+#
 
 # makepass-function
-function makepass {
-  local l=$1
-  local words
-  local first
-  local last
-  MAKEPASS_WORDLIST=${MAKEPASS_WORDLIST:-/usr/share/dict/words}
-  # if $l is not a number, then exit
-  [[ ! $l =~ ^[0-9]+$ ]] && [[ ! "$l" == "" ]] && echo "not a number" && return 1
-  (( l <= 1 || l > 255 )) && echo "Argument must be between 0 and 255" && return 1
-  # if $1 is actually empty, set $l to random value for each output
-
-  echo "Normal passwords:"
-  for _ in {1..10}; do
-    [ "$1" = "" ] && l=$(shuf -i 8-44 -n 1)
-    head -n10 /dev/urandom | tr -dc _A-Z-a-z-0-9 | cut -c-"${1:-$l}";
-  done | column
+function main {
+
+  # Getopts
+  while getopts 'hl:n:p' opt; do
+    case $opt in
+      h)
+        help && return 0;;
+      l)
+        if ! int_in_range "$OPTARG" 0 "$MAX"; then die "-l takes a number between 0 and $MAX"; fi
+        LENGTH=$OPTARG;;
+      n)
+        if ! int_in_range "$OPTARG" 1 "$MAX"; then die "-n takes a number between 1 and $MAX"; fi
+        NUMBER=$OPTARG;;
+      p)
+        PRINTLEN=1;;
+      *)
+        die "Unknown argument";;
+    esac
+  done
+  shift $((OPTIND - 1))
+
+
+  #
+  # Some error-checking
+  #
+
+  if [[ $# -gt 1 ]]; then die "only one argument"; fi
+
+  if [[ -n $1 ]]; then LENGTH=$1; fi
+
+  # Check $LENGTH and $NUMBER
+  if ! int_in_range "$LENGTH" 0 "$MAX"; then die "length must be a number between 0 and $MAX"; fi
+  if ! int_in_range "$NUMBER" 0 "$MAX"; then die "number-argument must be between and $MAX"; fi
+
+
+  #
+  # Some other work
+  #
+
+  if (( PRINTLEN )); then PRINTLEN=$((LENGTH < 100 ? 2 : 3)); fi
+
+  COL_WIDTH=$(( ( LENGTH ? LENGTH : RANGE_MAX ) + 2 ))
+  COL_NUM=$(( XWIDTH / ( COL_WIDTH + ( PRINTLEN ? PRINTLEN + 1 : 0 )) ))
+
+
+
+  #
+  # Print!
+  #
+
+  print_columns "Normal passwords" "$NUMBER" "$NORMAL"
+
   echo ""
 
-  echo "Passwords with special characters:"
-  for _ in {1..6}; do
-    [ "$1" = "" ] && l=$(shuf -i 16-64 -n 1)
-    first=$(head -n10 /dev/urandom | tr -dc A-Za-z | cut -c-1)
-    words=$(head -n10 /dev/urandom | tr -dc '!#$%&/()=?+-_,.;:<>[]{}|\@*^A-Z-a-z-0-9' | cut -c-"${1:-$l}")
-    last=$(head  -n10 /dev/urandom | tr -dc A-Za-z | cut -c-1)
-    echo "${first}${words}${last}"
-  done | column
+  print_columns "Passwords with special characters" "$((NUMBER*2/3))" "$SPECIAL"
 
   if [ -r "${MAKEPASS_WORDLIST}" ]; then
     echo ""
     echo "Passphrases:"
 
-    for _ in {1..5}; do
-      words=$(shuf -n 8 "${MAKEPASS_WORDLIST}" | tr '\n' '-' | tr -dc '_A-Z-a-z-0-9')
-      echo "${words:0:-1}"
+    mapfile -t WORDS < "${WORDLIST}"
+
+    for ((i=0; i < (NUMBER / 2); i++)); do
+      passphrase
     done;
   fi
+
+
+}
+
+# Function to print passwords in neat columns
+function print_columns {
+  local title=$1
+  local num=$2
+  local chars=$3
+  local i
+
+  local strings=()
+  for ((i=0; i < num; i++)); do
+    strings+=("$(randstring "$chars")")
+  done
+
+  echo "${title}:"
+
+  i=0
+  for s in "${strings[@]}"; do
+    ((i++))
+    if (( PRINTLEN )); then printf "%0${PRINTLEN}i " "${#s}"; fi
+    printf "%-${COL_WIDTH}s" "$s"
+    if ((i % COL_NUM == 0 || (i == num && i % COL_NUM > 0) )); then echo ""; fi
+  done
+}
+
+# Function to create random strings
+function randstring {
+  local chars=${1:-$NORMAL}
+  local string
+  local len=$(( LENGTH ? LENGTH : RANDOM % (RANGE_MAX - RANGE_MIN + 1) + RANGE_MIN ))
+
+  string+="${ALPHA:$((RANDOM % ${#ALPHA})):1}"
+  while (( ${#string} <= len - 2 )); do string+="${chars:$((RANDOM % ${#chars})):1}"; done
+  if (( len >= 2 )); then string+="${ALNUM:$((RANDOM % ${#ALNUM})):1}"; fi
+
+  echo "$string"
+}
+
+# PASSPHRASE!!
+function passphrase {
+  local string
+  local i
+  for ((i=0; i < PASS_WORDS; i++)); do
+    string+="${WORDS[$((RANDOM % ${#WORDS[@]}))]}-"
+  done
+  string="${string:0:-1}"
+
+  echo "$string"
+}
+
+# Check if int and if in range
+function int_in_range {
+  local num=$1
+  local min=$2
+  local max=$3
+
+  if [[ $num =~ ^[0-9]+$ && $min -le $num && $num -le $max ]]; then
+    return 0
+  fi
+  return 1
+}
+
+# Function to die
+function die() {
+  echo -- "$@"
+  echo -- "Maybe try running \`makepass -h\` for help"
+  exit 1
+}
+
+# Help-function
+function help {
+  echo $'NAME
+    makepass - create several random passwords
+
+SYNOPSIS
+    makepass [OPTIONS] [NUM]
+
+    If a NUM is provided, passwords will be NUM characters long.
+
+    By default `makepass` will output passwords from the three following classes:
+
+    - Normal passwords - random strings with letters (both lower and upper
+      case), numbers, and dashes and underscores.
+
+    - Passwords with special characters - random strings generated from lower
+      and upper case letters, numbers, and the following characters:
+      !#$%&/()=?+-_,.;:<>[]{}|@*
+
+    - Passphrases - if we find a dictionary, a series of eight random words
+      from the dictionary, separated by dashes. The number of words can not be
+      changed, but you do not have to use all of them. Use as mane as you want.
+
+    The first character will always be alphabetic, and the last will always be
+    alphanumeric.
+
+DESCRIPTION
+    makepass has the following options:
+
+    -h
+        output this help-text
+    -l
+        length of passwords. See MAKEPASS_LENGTH below
+    -n
+        number of passwords. See MAKEPASS_NUMBER below
+    -p
+        print length of number
+
+ENVIRONMENT
+    makepass examines the following environmental variables.
+
+    MAKEPASS_LENGTH
+        Specifies the length of passwords. Valid values are 0-255. If 0, a
+        random value between 8 and 42 will be used for each password. -l
+        overrides this environmental variable, and the argument NUM overrides
+        that again. So `MAKEPASS_LENGTH=10 makepass -l 12 14` will give
+        passwords that are 14 characters long, even though both -l and
+        MAKEPASS_LENGTH also specifies a length.
+
+    MAKEPASS_NUMBER
+        The number of passwords to generate. This formula is used to determine
+        how many passwords from each group should be generated:
+        - (n) normal passwords
+        - (n / 3 * 2 + 1) special passwords
+        - (n / 2) passphrases
+        Where n is 10 by default. Valid values for n are 1-255. Floating-poing
+        math is not used, so results may vary.
+
+    MAKEPASS_PRINTLEN
+        If 1, print length of all passwords. If 0, don\'t.
+
+    MAKEPASS_NORMAL
+        String of characters from which to generate "normal" passwords.
+        Defaults to:
+        abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_
+
+    MAKEPASS_SPECIAL
+        String of characters from which to generate passwords with special
+        characters. Defaults to the same characters as in MAKEPASS_NORMAL, plus
+        these:
+        !#$%&/()=?+-_,.;:<>[]{}|@*
+
+    MAKEPASS_WORDLIST
+        Specifies the dictionary we find words for passphrases in. If this is
+        unset or empty, we try "/usr/share/dict/words". If that file does not
+        exist, no passphrases will be provided.
+
+NOTES
+    This scripts makes use of $RANDOM - a builtin in bash which produces a
+    pseudo-random integer, newly generated each time the parameter is
+    referenced. This should provide enough randomnes to generate sufficiently
+    secure passwords.
+
+AUTHOR
+    Dennis Eriksen <https://dnns.no>'
+
+  return 0
 }
 
-makepass "${@:-}"
+# RUN IT!
+main "${@:-}"
 
 ## END OF FILE #################################################################