+#!/usr/bin/perl
+#
+# A git daemon with an added userv security boundary.
+#
+# This was written by Tony Finch <dot@dotat.at> and subsequently
+# heavily modified by Ian Jackson <ijackson@chiark.greenend.org.uk>
+# http://creativecommons.org/publicdomain/zero/1.0/
+
+use strict;
+use warnings;
+
+use POSIX;
+use Socket;
+use Sys::Syslog;
+
+BEGIN {
+ if ($ARGV[0] =~ s/^-L//) {
+ my $logfile= shift @ARGV;
+ open STDERR, ">> $logfile" or die $!;
+ }
+}
+
+sub ntoa {
+ my $sockaddr = shift;
+ return ('(local)') unless defined $sockaddr;
+ my ($port,$addr) = sockaddr_in $sockaddr;
+ $addr = inet_ntoa $addr;
+ return ("[$addr]:$port",$addr,$port);
+}
+our ($client,$client_addr,$client_port) = ntoa getpeername STDIN;
+our ($server,$server_addr,$server_port) = ntoa getsockname STDIN;
+our ($service,$specpath,$spechost);
+
+printf STDERR "%s [$$] %s %s\n",
+ strftime("%Y-%m-%d %H:%M:%S %Z", localtime), $server, $client;
+
+openlog 'userv-git-daemon', 'pid', 'daemon';
+sub fail { syslog 'err', "$client @_"; exit }
+
+$SIG{ALRM} = sub { fail "timeout" };
+alarm 30;
+
+sub xread {
+ my $length = shift;
+ my $buffer = "";
+ while ($length > length $buffer) {
+ my $ret = sysread STDIN, $buffer, $length, length $buffer;
+ fail "Expected $length bytes, got ".length $buffer
+ if defined $ret and $ret == 0;
+ fail "read: $!" if not defined $ret and $! != EINTR and $! != EAGAIN;
+ }
+ return $buffer;
+}
+my $hex_len = xread 4;
+fail "Bad hex in packet length" unless $hex_len =~ m|^[0-9a-fA-F]{4}$|;
+my $line = xread -4 + hex $hex_len;
+unless (($service,$specpath,$spechost) = $line =~
+ m|^(git-[a-z-]+) /*([!-~]+)\0host=([!-~]+)\0$|) {
+ $line =~ s|[^ -~]+| |g;
+ fail "Could not parse \"$line\""
+}
+
+@@READ_URLMAP@@
+
+fail "No global mapping for $uri" unless defined $serve_user;
+
+my ($hn,$ha,$at,$naddrs,@addrs) = gethostbyname $spechost;
+fail "hostname/address mismatch ($spechost $server_addr)" unless grep {
+ $server_addr eq inet_ntoa $_
+ } @addrs;
+
+our @opts;
+
+push @opts, "-D$_=${$::{$_}}"
+ for qw(service specpath spechost
+ client client_addr client_port
+ server server_addr server_port);
+
+fail "no user $serve_user" unless getpwnam($serve_user);
+
+syslog 'notice', "$client $service $uri $serve_user";
+
+my @cmd = ('userv', '-t300', @opts, $serve_user, $service);
+no warnings; # suppress errors to stderr
+exec @cmd or fail "exec userv: $!";
+
+# end