#!/usr/bin/perl


# Perl c_rehash script, scan all files in a directory
# and add symbolic links to their hash values.

my $openssl;

my $dir = "/etc/sipxpbx/ssl/authorities";

$openssl = "/usr/bin/openssl";

die "ca_rehash: rehashing skipped ('openssl' program not available)\n"
    unless -x $openssl;

$ENV{OPENSSL} = $openssl;

if (@ARGV) {
    @dirlist = @ARGV;
} else {
    @dirlist = ( $dir );
}

foreach (@dirlist) {
   print STDERR "hashing $_\n";
	if(-d $_ and -w $_) {
		hash_dir($_);
	}
}

sub hash_dir {
	my %hashlist;
	chdir $_[0];
	opendir(DIR, ".");
	my @flist = readdir(DIR);
	# Delete any existing symbolic links
	foreach (grep {/^[\da-f]+\.r{0,1}\d+$/} @flist) {
		if(-l $_) {
			unlink $_;
		}
	}
	closedir DIR;
	FILE: foreach $fname (grep {/\.(pem|crt|crl)$/} @flist) {
		# Check to see if certificates and/or CRLs present.
		my ($cert, $crl) = check_file($fname);
		if(!$cert && !$crl) {
			print STDERR "WARNING: $fname does not contain a certificate or CRL: skipping\n";
			next;
		}
		link_hash_cert($fname) if($cert);
		link_hash_crl($fname) if($crl);
	}
}

sub check_file {
	my ($is_cert, $is_crl) = (0,0);
	my $fname = $_[0];
	open IN, $fname;
	while(<IN>) {
		if(/^-----BEGIN (.*)-----/) {
			my $hdr = $1;
			if($hdr =~ /^(X509 |TRUSTED |)CERTIFICATE$/) {
				$is_cert = 1;
				last if($is_crl);
			} elsif($hdr eq "X509 CRL") {
				$is_crl = 1;
				last if($is_cert);
			}
		}
	}
	close IN;
	return ($is_cert, $is_crl);
}


# Link a certificate to its subject name hash value, each hash is of
# the form <hash>.<n> where n is an integer. If the hash value already exists
# then we need to up the value of n, unless its a duplicate in which
# case we skip the link. We check for duplicates by comparing the
# certificate fingerprints

sub link_hash_cert {
		my $fname = $_[0];
		$fname =~ s/'/'\\''/g;
		my ($hash, $fprint) = `"$openssl" x509 -hash -fingerprint -noout -in '$fname'`;
		chomp $hash;
		chomp $fprint;
		$fprint =~ s/^.*=//;
		$fprint =~ tr/://d;
		my $suffix = 0;
		# Search for an unused hash filename
		while(exists $hashlist{"$hash.$suffix"}) {
			# Hash matches: if fingerprint matches its a duplicate cert
			if($hashlist{"$hash.$suffix"} eq $fprint) {
				print STDERR "WARNING: Skipping duplicate certificate $fname\n";
				return;
			}
			$suffix++;
		}
		$hash .= ".$suffix";
		print "$fname => $hash\n";
		$symlink_exists=eval {symlink("",""); 1};
		if ($symlink_exists) {
			symlink $fname, $hash;
		} else {
			system ("cp", $fname, $hash);
		}
		$hashlist{$hash} = $fprint;
}

# Same as above except for a CRL. CRL links are of the form <hash>.r<n>

sub link_hash_crl {
		my $fname = $_[0];
		$fname =~ s/'/'\\''/g;
		my ($hash, $fprint) = `"$openssl" crl -hash -fingerprint -noout -in '$fname'`;
		chomp $hash;
		chomp $fprint;
		$fprint =~ s/^.*=//;
		$fprint =~ tr/://d;
		my $suffix = 0;
		# Search for an unused hash filename
		while(exists $hashlist{"$hash.r$suffix"}) {
			# Hash matches: if fingerprint matches its a duplicate cert
			if($hashlist{"$hash.r$suffix"} eq $fprint) {
				print STDERR "WARNING: Skipping duplicate CRL $fname\n";
				return;
			}
			$suffix++;
		}
		$hash .= ".r$suffix";

		$symlink_exists=eval {symlink("",""); 1};
		if ($symlink_exists) {
			symlink $fname, $hash;
		} else {
			system ("cp", $fname, $hash);
		}
		$hashlist{$hash} = $fprint;
}
