#!/usr/bin/perl -w
# (c) Christoph Berg <cb@df7cb.de>
# This program is free software covered by the GPL.
# $Id: purgesigs,v 1.7 2004/07/05 23:03:09 cb Exp $
#
# This program removes all uids except one and all unknown signatures from a
# gpg key.
#
# 031017 cb v0.1
# 031017 cb v0.1a: -qmfu flags
# 031019 cb v0.1b: removed stray [ from regexps
# 040222 cb v0.2: support for revoked keys (Tollef Fog Heen)
# 2004-07-02 cb
# 2004-07-06 cb: purging subkeys

use strict;
my $version = "2004-07-06";

$ENV{LC_ALL} = "C";

my %opts;
use Getopt::Std;
getopts('v', \%opts);

sub help {
	print <<EOT;
purgekey $version (c) 2003, 2004 Christoph Berg <cb\@df7cb.de>

Syntax: $0 keyring keyid uid_nr
EOT

	exit 0;
}

my $keyring = shift || help();
my $keyid = shift || help();
my $uid_nr = shift || help();

my $uid_count = 0;
my $found = 0;
my $uid_string;

open G, "gpg --no-default-keyring --keyring $keyring --list-key --fixed-list-mode --with-colon $keyid |" or die "gpg: $!";
while (<G>) {
	print if $opts{v};
	chomp;
	next if /^tru:/; # TODO: what's that? trust?
	next if /^sub:/;
	#pub:q:1024:17:0596CD7FCA9EADCF:1062764361:::-:::scESC:
	if(/^pub:[-qmfu]:\d{3,}:\d+:[0-9A-F]+:\d+:\d*::[-qmfu]:::[escESC]+:$/) {
		$found = 1;
	} elsif(/^uid:[-qmfu]::::::::(.+):$/) {
		$uid_count++;
		$uid_string = $1 if $uid_count == $uid_nr;
	} elsif(/^(uid|uat):[-qmfur]::::::::(.+):$/) {
		$uid_count++;
	} else {
		die "unknown line format: $_";
	}
}
close G;

die "Key '$keyid' not found" unless $found;
die "uid_nr $uid_nr > uid_count $uid_count" if $uid_nr > $uid_count;

print "$keyring: purging key $keyid / uid $uid_nr/$uid_count\n" if $opts{v};
system "expect purgesigs.expect $keyring $keyid $uid_nr $uid_count > /dev/null";
die "Something went wrong with purgesigs.expect" if $? >> 8 > 0;

sleep 1;

$uid_count = 0;
$found = 0;

open G, "gpg --no-default-keyring --keyring $keyring --list-key --fixed-list-mode --with-colon $keyid |" or die "gpg: $!";
while (<G>) {
	print if $opts{v};
	chomp;
	next if /^tru:/; # TODO: what's that? trust?
	next if /^sub:/;
	#pub:q:1024:17:0596CD7FCA9EADCF:1062764361:::-:::scESC:
	if(/^pub:[-qmfu]:\d{3,}:\d+:[0-9A-F]+:\d+:\d*::[-qmfu]:::[escESC]+:$/) {
		$found = 1;
	} elsif(/^uid:[-qmfu]::::::::(.+):$/) {
		$uid_count++;
		die "purgesigs failed: more than one uid left in $keyring" if $uid_count > 1;
		die "wrong uid ($1) cut out, expected $uid_string" if $1 ne $uid_string;
	} elsif(/^(uid|uat):[-qmfu]::::::::(.+):$/) {
		$uid_count++;
	} else {
		die "unknown line format: $_";
	}
}
close G;

die "Key '$keyid' not found" unless $found or $uid_count == 0;