Implement PUSH in daemon

When a daemon receices a push command, it checks whether it already has
the offered file or not. If not, it calls back to the daemon where the
push originated and pulls the file over tcp.

clusterd

@@ -582,6 +582,7 @@ our %UDP_HANDLER=
 	'make-automaps' => \&udp_rx_make_automaps,
 	'log'  => \&udp_rx_log,
 	'exec' => \&udp_rx_exec,
+	'push' => \&udp_rx_push,
 );
 
 sub udp_message {
@@ -1667,6 +1668,79 @@ sub cmd_msg {
 	}
 }
 
+sub udp_rx_push {
+	my ($ip,$st_want)=@_;
+
+	my $filename=$st_want->name;
+	my $tmp_filename="$filename.tmp";
+
+	$ip eq $my_ip and return;
+
+	my $st_is=Donald::FileInfo->lstat($st_want->name);
+
+	unless ($st_want->type eq 'F') {
+		warn "$filename: type ".$st_want->type." not yet implemented\n";
+		return;
+	}
+
+	if ($st_is
+		&& $st_is->type eq 'F'
+		&& $st_is->size == $st_want->size
+		&& $st_is->mtime == $st_want->mtime
+		&& $st_is->uid == $st_want->uid
+		&& $st_is->gid == $st_want->gid
+		&& $st_is->perm == $st_want->perm
+	) {
+		warn "$filename: already okay\n";
+		return;
+	}
+
+	if ($st_want->size==0) {
+		my $fh=IO::File->new($tmp_filename,O_WRONLY|O_CREAT,0);
+		defined $fh or return warn "$tmp_filename: $!\n";
+		$fh->close;
+		chown $st_want->uid,$st_want->gid,$tmp_filename or return warn "$tmp_filename: $!\n";
+		chmod $st_want->perm,$tmp_filename or return warn "$tmp_filename: $!\n";
+		rename($tmp_filename,$filename);
+		utime($st_want->mtime,$st_want->mtime,$filename);
+		warn "installed (empty) $filename\n";
+		return;
+	}
+
+	my $s;
+	$s=My::Select::INET::connect_tcp($ip,$CLP_PORT,5,sub {
+		$! and return warn "$ip: $!\n";
+		send_tcp_cp($s,sub {
+			$! and return warn "$ip: $!\n";
+			my $fh = IO::File->new($tmp_filename,O_WRONLY|O_CREAT,0);
+			defined $fh or return warn "$tmp_filename: $!\n";
+
+			my $cb;
+			my $bytes=$st_want->size;
+			$cb=sub {
+				# note, we need to break the circular references $cb of our caller, if no longer needed
+				my ($buf)=@_;
+				if ($!) { warn "$ip: $!\n";$cb=undef;return; }
+				if (length($buf)==0) { warn "$ip: EOF\n";$cb=undef;return;}
+				print $fh $buf;
+				$bytes-=length($buf);
+				if ($bytes>0) {
+					My::Select::INET::read_with_timeout($s,$cb,5);
+					return;
+				}
+				$cb=undef;
+				close $fh;
+				chown $st_want->uid,$st_want->gid,$tmp_filename or return warn "$tmp_filename: $!\n";
+				chmod $st_want->perm,$tmp_filename or return warn "$tmp_filename: $!\n";
+				rename($tmp_filename,$filename) or return warn "$filename: $!\n";
+				utime($st_want->mtime,$st_want->mtime,$filename);
+				warn "installed $filename\n";
+			};
+			My::Select::INET::read_with_timeout($s,$cb,5);
+		},5,'PULL',$st_want);
+	});
+}
+
 sub cmd_push {
 	my @files=@_;
 	for my $filename (@files) {
@@ -1679,6 +1753,7 @@ sub cmd_push {
 		my $st=Donald::FileInfo->lstat($filename);
 		defined $st or die "$filename: $!\n";
 		$st->type eq 'F' or die "$filename: only plain files currently supported\n";
+		open my $test,'<',$filename or die "$filename: $!\n";
 		udp_broadcast_message($donald_s,'push',$my_ip,$st);
 	}
 }