daemon: support listening on Unix domain sockets

Listening on Unix domain sockets can be convenient for running
behind reverse proxies, avoiding port conflicts, limiting access,
or avoiding the overhead (if any) of TCP over loopback.

1 files changed, 25 insertions, 2 deletions

diff --git a/t/httpd-corner.t b/t/httpd-corner.t
index 198a7e90..19564074 100644
--- a/t/httpd-corner.t
+++ b/t/httpd-corner.t
@@ -16,6 +16,7 @@ use Digest::SHA qw(sha1_hex);
 use File::Temp qw/tempdir/;
 use Cwd qw/getcwd/;
 use IO::Socket;
+use IO::Socket::UNIX;
 use Fcntl qw(FD_CLOEXEC F_SETFD F_GETFD :seek);
 use Socket qw(SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY);
 use POSIX qw(dup2 mkfifo :sys_wait_h);
@@ -34,20 +35,32 @@ my %opts = (
         Listen => 1024,
 );
 my $sock = IO::Socket::INET->new(%opts);
+my $upath = "$tmpdir/s";
+my $unix = IO::Socket::UNIX->new(
+        Listen => 1024,
+        Type => SOCK_STREAM,
+        Local => $upath
+);
+ok($unix, 'UNIX socket created');
 my $pid;
 END { kill 'TERM', $pid if defined $pid };
 my $spawn_httpd = sub {
         my (@args) = @_;
+        $! = 0;
         my $fl = fcntl($sock, F_GETFD, 0);
         ok(! $!, 'no error from fcntl(F_GETFD)');
         is($fl, FD_CLOEXEC, 'cloexec set by default (Perl behavior)');
         $pid = fork;
         if ($pid == 0) {
                 # pretend to be systemd
-                fcntl($sock, F_SETFD, $fl &= ~FD_CLOEXEC);
                 dup2(fileno($sock), 3) or die "dup2 failed: $!\n";
+                dup2(fileno($unix), 4) or die "dup2 failed: $!\n";
+                $sock = IO::Handle->new_from_fd(3, 'r');
+                $sock->fcntl(F_SETFD, 0);
+                $unix = IO::Handle->new_from_fd(4, 'r');
+                $unix->fcntl(F_SETFD, 0);
                 $ENV{LISTEN_PID} = $$;
-                $ENV{LISTEN_FDS} = 1;
+                $ENV{LISTEN_FDS} = 2;
                 exec $httpd, @args, "--stdout=$out", "--stderr=$err", $psgi;
                 die "FAIL: $!\n";
         }
@@ -63,6 +76,16 @@ my $spawn_httpd = sub {
         $spawn_httpd->('-W0');
 }
 
+# Unix domain sockets
+{
+        my $u = IO::Socket::UNIX->new(Type => SOCK_STREAM, Peer => $upath);
+        ok($u, 'unix socket connected');
+        $u->write("GET /host-port HTTP/1.0\r\n\r\n");
+        $u->read(my $buf, 4096);
+        like($buf, qr!\r\n\r\n127\.0\.0\.1:0\z!,
+                'set REMOTE_ADDR and REMOTE_PORT for Unix socket');
+}
+
 sub conn_for {
         my ($sock, $msg) = @_;
         my $conn = IO::Socket::INET->new(