commit - 6fd928d3ad33d035b79e6b65bf4f9f97accde929
commit + 61b3aef3ae1eb23a5e7b0c549834f2e92d6ecd44
blob - fea1b875ed455c79d06ba72ddc12fdda497cb882
blob + 0ddb2393d03c00c99b9269d75b59fd5cc6a520ac
--- pwg
+++ pwg
-#!/bin/sh
+#!/usr/bin/env perl
#
-# Copyright (c) 2022 Omar Polo <op@omarpolo.com>
+# Copyright (c) 2022, 2023 Omar Polo <op@omarpolo.com>
+# Copyright (c) 2023 Alexander Arkhipov <aa@alearx.org>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-me=$(basename "$0")
+use strict;
+use warnings;
+use v5.32;
-usage() {
- echo "usage: $me [-an] [-w wordlist] [len]" >&2
- exit 1
+use open ":std", ":encoding(UTF-8)";
+
+use Getopt::Long qw(:config bundling require_order);
+use File::Basename;
+
+my $urandom; # opened later
+
+my $chars = "\x20-\x7E";
+my $wordlist;
+my $length = 32;
+
+my $me = basename $0;
+sub usage {
+ say STDERR "usage: $me [-anu] [-w wordlist] [len]";
+ exit(1);
}
-wordlist=
-chars="[:print:]"
-len=32
+# not really arc4random but closer...
+sub arc4random {
+ my $r = read($urandom, my $buf, 4)
+ or die "$me: failed to read /dev/urandom: $!\n";
+ die "$me: short read\n" if $r != 4;
+ return unpack('L', $buf);
+}
-while getopts anw: ch; do
- case $ch in
- a) chars="[:alnum:]" ;;
- n) chars="[:digit:]" ;;
- w) wordlist="$OPTARG"; len=6 ;;
- ?) usage ;;
- esac
-done
-shift $(($OPTIND - 1))
+# Calculate a uniformly distributed random number less than $upper_bound
+# avoiding "modulo bias".
+#
+# Uniformity is achieved by generating new random numbers until the one
+# returned is outside the range [0, 2**32 % $upper_bound). This
+# guarantees the selected random number will be inside
+# [2**32 % $upper_bound, 2**32) which maps back to [0, $upper_bound)
+# after reduction modulo $upper_bound.
+sub randline {
+ my $upper_bound = shift;
-[ $# -gt 1 ] && usage
-[ $# -eq 1 ] && len="$1"
+ return 0 if $upper_bound < 2;
-if [ -n "$wordlist" ]; then
- passphrase=$(sort -R -- "$wordlist" | head -n "$len")
- [ -n "$passphrase" ] && printf '%s\n' "$passphrase"
-else
- export LC_ALL=C
- tr -cd "$chars" </dev/urandom | dd bs=1 count="$len" 2>/dev/null && \
- echo
-fi
+ my $min = 2**32 % $upper_bound;
+
+ # This could theoretically loop forever but each retry has
+ # p > 0.5 (worst case, usually far better) of selecting a
+ # number inside the range we need, so it should rarely need
+ # to re-roll.
+ my $r;
+ while (1) {
+ $r = arc4random;
+ last if $r >= $min;
+ }
+ return $r % $upper_bound;
+}
+
+GetOptions(
+ "a" => sub { $chars = "0-9a-zA-Z" },
+ "n" => sub { $chars = "0-9" },
+ "w=s" => \$wordlist,
+ ) or usage;
+
+$length = 6 if defined $wordlist;
+$length = shift if @ARGV;
+die "$me: invalid length: $length\n" unless $length =~ /^\d+$/;
+
+open($urandom, "<:raw", "/dev/urandom")
+ or die "$me: can't open /dev/urandom: $!\n";
+
+if (not defined $wordlist) {
+ my $pass = "";
+ my $l = $length;
+ while ($l >= 0) {
+ read($urandom, my $t, 128)
+ or die "$me: failed to read /dev/urandom: $!\n";
+ $t =~ s/[^$chars]//g;
+ $l -= length($t);
+ $pass .= $t;
+ }
+ say substr($pass, 0, $length);
+ exit 0;
+}
+
+open(my $fh, "<", $wordlist) or die "$me: can't open $wordlist: $!\n";
+
+my @lines = (0);
+push @lines, tell $fh while <$fh>;
+
+while ($length--) {
+ seek $fh, $lines[randline scalar(@lines)], 0
+ or die "$me: seek: $!\n";
+ my $line = <$fh>;
+ chomp($line);
+ print $line;
+ print " " if $length;
+}
+say "";
blob - 529c53f3bb2a4c4e1a63bdc8b626bef4edbafc6f
blob + 99459b6656af8d247596bddecaaaa77e6b8a3950
--- pwg.1
+++ pwg.1
-.\" Copyright (c) 2021, 2022 Omar Polo <op@omarpolo.com>
+.\" Copyright (c) 2021, 2022, 2023 Omar Polo <op@omarpolo.com>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
It generates a random string of characters or a diceware-style pass
phrase.
The random properties are the ones provided by the operating system'
-.Pa /dev/urandom
-and
-.Xr sort 1
-.Fl R .
+.Pa /dev/urandom .
.Pp
The options are as follows:
.Bl -tag -width Ds
