Adding upstream version 1.20.14.upstream/1.20.14upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

8 files changed, 2674 insertions, 0 deletions

diff --git a/src/net/rpc/client.go b/src/net/rpc/client.go
new file mode 100644
index 0000000..42d1351
--- /dev/null
+++ b/src/net/rpc/client.go
@@ -0,0 +1,323 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package rpc
+
+import (
+	"bufio"
+	"encoding/gob"
+	"errors"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"sync"
+)
+
+// ServerError represents an error that has been returned from
+// the remote side of the RPC connection.
+type ServerError string
+
+func (e ServerError) Error() string {
+	return string(e)
+}
+
+var ErrShutdown = errors.New("connection is shut down")
+
+// Call represents an active RPC.
+type Call struct {
+	ServiceMethod string     // The name of the service and method to call.
+	Args          any        // The argument to the function (*struct).
+	Reply         any        // The reply from the function (*struct).
+	Error         error      // After completion, the error status.
+	Done          chan *Call // Receives *Call when Go is complete.
+}
+
+// Client represents an RPC Client.
+// There may be multiple outstanding Calls associated
+// with a single Client, and a Client may be used by
+// multiple goroutines simultaneously.
+type Client struct {
+	codec ClientCodec
+
+	reqMutex sync.Mutex // protects following
+	request  Request
+
+	mutex    sync.Mutex // protects following
+	seq      uint64
+	pending  map[uint64]*Call
+	closing  bool // user has called Close
+	shutdown bool // server has told us to stop
+}
+
+// A ClientCodec implements writing of RPC requests and
+// reading of RPC responses for the client side of an RPC session.
+// The client calls WriteRequest to write a request to the connection
+// and calls ReadResponseHeader and ReadResponseBody in pairs
+// to read responses. The client calls Close when finished with the
+// connection. ReadResponseBody may be called with a nil
+// argument to force the body of the response to be read and then
+// discarded.
+// See NewClient's comment for information about concurrent access.
+type ClientCodec interface {
+	WriteRequest(*Request, any) error
+	ReadResponseHeader(*Response) error
+	ReadResponseBody(any) error
+
+	Close() error
+}
+
+func (client *Client) send(call *Call) {
+	client.reqMutex.Lock()
+	defer client.reqMutex.Unlock()
+
+	// Register this call.
+	client.mutex.Lock()
+	if client.shutdown || client.closing {
+		client.mutex.Unlock()
+		call.Error = ErrShutdown
+		call.done()
+		return
+	}
+	seq := client.seq
+	client.seq++
+	client.pending[seq] = call
+	client.mutex.Unlock()
+
+	// Encode and send the request.
+	client.request.Seq = seq
+	client.request.ServiceMethod = call.ServiceMethod
+	err := client.codec.WriteRequest(&client.request, call.Args)
+	if err != nil {
+		client.mutex.Lock()
+		call = client.pending[seq]
+		delete(client.pending, seq)
+		client.mutex.Unlock()
+		if call != nil {
+			call.Error = err
+			call.done()
+		}
+	}
+}
+
+func (client *Client) input() {
+	var err error
+	var response Response
+	for err == nil {
+		response = Response{}
+		err = client.codec.ReadResponseHeader(&response)
+		if err != nil {
+			break
+		}
+		seq := response.Seq
+		client.mutex.Lock()
+		call := client.pending[seq]
+		delete(client.pending, seq)
+		client.mutex.Unlock()
+
+		switch {
+		case call == nil:
+			// We've got no pending call. That usually means that
+			// WriteRequest partially failed, and call was already
+			// removed; response is a server telling us about an
+			// error reading request body. We should still attempt
+			// to read error body, but there's no one to give it to.
+			err = client.codec.ReadResponseBody(nil)
+			if err != nil {
+				err = errors.New("reading error body: " + err.Error())
+			}
+		case response.Error != "":
+			// We've got an error response. Give this to the request;
+			// any subsequent requests will get the ReadResponseBody
+			// error if there is one.
+			call.Error = ServerError(response.Error)
+			err = client.codec.ReadResponseBody(nil)
+			if err != nil {
+				err = errors.New("reading error body: " + err.Error())
+			}
+			call.done()
+		default:
+			err = client.codec.ReadResponseBody(call.Reply)
+			if err != nil {
+				call.Error = errors.New("reading body " + err.Error())
+			}
+			call.done()
+		}
+	}
+	// Terminate pending calls.
+	client.reqMutex.Lock()
+	client.mutex.Lock()
+	client.shutdown = true
+	closing := client.closing
+	if err == io.EOF {
+		if closing {
+			err = ErrShutdown
+		} else {
+			err = io.ErrUnexpectedEOF
+		}
+	}
+	for _, call := range client.pending {
+		call.Error = err
+		call.done()
+	}
+	client.mutex.Unlock()
+	client.reqMutex.Unlock()
+	if debugLog && err != io.EOF && !closing {
+		log.Println("rpc: client protocol error:", err)
+	}
+}
+
+func (call *Call) done() {
+	select {
+	case call.Done <- call:
+		// ok
+	default:
+		// We don't want to block here. It is the caller's responsibility to make
+		// sure the channel has enough buffer space. See comment in Go().
+		if debugLog {
+			log.Println("rpc: discarding Call reply due to insufficient Done chan capacity")
+		}
+	}
+}
+
+// NewClient returns a new Client to handle requests to the
+// set of services at the other end of the connection.
+// It adds a buffer to the write side of the connection so
+// the header and payload are sent as a unit.
+//
+// The read and write halves of the connection are serialized independently,
+// so no interlocking is required. However each half may be accessed
+// concurrently so the implementation of conn should protect against
+// concurrent reads or concurrent writes.
+func NewClient(conn io.ReadWriteCloser) *Client {
+	encBuf := bufio.NewWriter(conn)
+	client := &gobClientCodec{conn, gob.NewDecoder(conn), gob.NewEncoder(encBuf), encBuf}
+	return NewClientWithCodec(client)
+}
+
+// NewClientWithCodec is like NewClient but uses the specified
+// codec to encode requests and decode responses.
+func NewClientWithCodec(codec ClientCodec) *Client {
+	client := &Client{
+		codec:   codec,
+		pending: make(map[uint64]*Call),
+	}
+	go client.input()
+	return client
+}
+
+type gobClientCodec struct {
+	rwc    io.ReadWriteCloser
+	dec    *gob.Decoder
+	enc    *gob.Encoder
+	encBuf *bufio.Writer
+}
+
+func (c *gobClientCodec) WriteRequest(r *Request, body any) (err error) {
+	if err = c.enc.Encode(r); err != nil {
+		return
+	}
+	if err = c.enc.Encode(body); err != nil {
+		return
+	}
+	return c.encBuf.Flush()
+}
+
+func (c *gobClientCodec) ReadResponseHeader(r *Response) error {
+	return c.dec.Decode(r)
+}
+
+func (c *gobClientCodec) ReadResponseBody(body any) error {
+	return c.dec.Decode(body)
+}
+
+func (c *gobClientCodec) Close() error {
+	return c.rwc.Close()
+}
+
+// DialHTTP connects to an HTTP RPC server at the specified network address
+// listening on the default HTTP RPC path.
+func DialHTTP(network, address string) (*Client, error) {
+	return DialHTTPPath(network, address, DefaultRPCPath)
+}
+
+// DialHTTPPath connects to an HTTP RPC server
+// at the specified network address and path.
+func DialHTTPPath(network, address, path string) (*Client, error) {
+	conn, err := net.Dial(network, address)
+	if err != nil {
+		return nil, err
+	}
+	io.WriteString(conn, "CONNECT "+path+" HTTP/1.0\n\n")
+
+	// Require successful HTTP response
+	// before switching to RPC protocol.
+	resp, err := http.ReadResponse(bufio.NewReader(conn), &http.Request{Method: "CONNECT"})
+	if err == nil && resp.Status == connected {
+		return NewClient(conn), nil
+	}
+	if err == nil {
+		err = errors.New("unexpected HTTP response: " + resp.Status)
+	}
+	conn.Close()
+	return nil, &net.OpError{
+		Op:   "dial-http",
+		Net:  network + " " + address,
+		Addr: nil,
+		Err:  err,
+	}
+}
+
+// Dial connects to an RPC server at the specified network address.
+func Dial(network, address string) (*Client, error) {
+	conn, err := net.Dial(network, address)
+	if err != nil {
+		return nil, err
+	}
+	return NewClient(conn), nil
+}
+
+// Close calls the underlying codec's Close method. If the connection is already
+// shutting down, ErrShutdown is returned.
+func (client *Client) Close() error {
+	client.mutex.Lock()
+	if client.closing {
+		client.mutex.Unlock()
+		return ErrShutdown
+	}
+	client.closing = true
+	client.mutex.Unlock()
+	return client.codec.Close()
+}
+
+// Go invokes the function asynchronously. It returns the Call structure representing
+// the invocation. The done channel will signal when the call is complete by returning
+// the same Call object. If done is nil, Go will allocate a new channel.
+// If non-nil, done must be buffered or Go will deliberately crash.
+func (client *Client) Go(serviceMethod string, args any, reply any, done chan *Call) *Call {
+	call := new(Call)
+	call.ServiceMethod = serviceMethod
+	call.Args = args
+	call.Reply = reply
+	if done == nil {
+		done = make(chan *Call, 10) // buffered.
+	} else {
+		// If caller passes done != nil, it must arrange that
+		// done has enough buffer for the number of simultaneous
+		// RPCs that will be using that channel. If the channel
+		// is totally unbuffered, it's best not to run at all.
+		if cap(done) == 0 {
+			log.Panic("rpc: done channel is unbuffered")
+		}
+	}
+	call.Done = done
+	client.send(call)
+	return call
+}
+
+// Call invokes the named function, waits for it to complete, and returns its error status.
+func (client *Client) Call(serviceMethod string, args any, reply any) error {
+	call := <-client.Go(serviceMethod, args, reply, make(chan *Call, 1)).Done
+	return call.Error
+}
diff --git a/src/net/rpc/client_test.go b/src/net/rpc/client_test.go
new file mode 100644
index 0000000..ffc12fa
--- /dev/null
+++ b/src/net/rpc/client_test.go
@@ -0,0 +1,87 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package rpc
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+	"testing"
+)
+
+type shutdownCodec struct {
+	responded chan int
+	closed    bool
+}
+
+func (c *shutdownCodec) WriteRequest(*Request, any) error { return nil }
+func (c *shutdownCodec) ReadResponseBody(any) error       { return nil }
+func (c *shutdownCodec) ReadResponseHeader(*Response) error {
+	c.responded <- 1
+	return errors.New("shutdownCodec ReadResponseHeader")
+}
+func (c *shutdownCodec) Close() error {
+	c.closed = true
+	return nil
+}
+
+func TestCloseCodec(t *testing.T) {
+	codec := &shutdownCodec{responded: make(chan int)}
+	client := NewClientWithCodec(codec)
+	<-codec.responded
+	client.Close()
+	if !codec.closed {
+		t.Error("client.Close did not close codec")
+	}
+}
+
+// Test that errors in gob shut down the connection. Issue 7689.
+
+type R struct {
+	msg []byte // Not exported, so R does not work with gob.
+}
+
+type S struct{}
+
+func (s *S) Recv(nul *struct{}, reply *R) error {
+	*reply = R{[]byte("foo")}
+	return nil
+}
+
+func TestGobError(t *testing.T) {
+	defer func() {
+		err := recover()
+		if err == nil {
+			t.Fatal("no error")
+		}
+		if !strings.Contains(err.(error).Error(), "reading body unexpected EOF") {
+			t.Fatal("expected `reading body unexpected EOF', got", err)
+		}
+	}()
+	Register(new(S))
+
+	listen, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		panic(err)
+	}
+	go Accept(listen)
+
+	client, err := Dial("tcp", listen.Addr().String())
+	if err != nil {
+		panic(err)
+	}
+
+	var reply Reply
+	err = client.Call("S.Recv", &struct{}{}, &reply)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("%#v\n", reply)
+	client.Close()
+
+	listen.Close()
+}
diff --git a/src/net/rpc/debug.go b/src/net/rpc/debug.go
new file mode 100644
index 0000000..9e499fd
--- /dev/null
+++ b/src/net/rpc/debug.go
@@ -0,0 +1,90 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package rpc
+
+/*
+	Some HTML presented at http://machine:port/debug/rpc
+	Lists services, their methods, and some statistics, still rudimentary.
+*/
+
+import (
+	"fmt"
+	"html/template"
+	"net/http"
+	"sort"
+)
+
+const debugText = `<html>
+	<body>
+	<title>Services</title>
+	{{range .}}
+	<hr>
+	Service {{.Name}}
+	<hr>
+		<table>
+		<th align=center>Method</th><th align=center>Calls</th>
+		{{range .Method}}
+			<tr>
+			<td align=left font=fixed>{{.Name}}({{.Type.ArgType}}, {{.Type.ReplyType}}) error</td>
+			<td align=center>{{.Type.NumCalls}}</td>
+			</tr>
+		{{end}}
+		</table>
+	{{end}}
+	</body>
+	</html>`
+
+var debug = template.Must(template.New("RPC debug").Parse(debugText))
+
+// If set, print log statements for internal and I/O errors.
+var debugLog = false
+
+type debugMethod struct {
+	Type *methodType
+	Name string
+}
+
+type methodArray []debugMethod
+
+type debugService struct {
+	Service *service
+	Name    string
+	Method  methodArray
+}
+
+type serviceArray []debugService
+
+func (s serviceArray) Len() int           { return len(s) }
+func (s serviceArray) Less(i, j int) bool { return s[i].Name < s[j].Name }
+func (s serviceArray) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+
+func (m methodArray) Len() int           { return len(m) }
+func (m methodArray) Less(i, j int) bool { return m[i].Name < m[j].Name }
+func (m methodArray) Swap(i, j int)      { m[i], m[j] = m[j], m[i] }
+
+type debugHTTP struct {
+	*Server
+}
+
+// Runs at /debug/rpc
+func (server debugHTTP) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	// Build a sorted version of the data.
+	var services serviceArray
+	server.serviceMap.Range(func(snamei, svci any) bool {
+		svc := svci.(*service)
+		ds := debugService{svc, snamei.(string), make(methodArray, 0, len(svc.method))}
+		for mname, method := range svc.method {
+			ds.Method = append(ds.Method, debugMethod{method, mname})
+		}
+		sort.Sort(ds.Method)
+		services = append(services, ds)
+		return true
+	})
+	sort.Sort(services)
+	err := debug.Execute(w, services)
+	if err != nil {
+		fmt.Fprintln(w, "rpc: error executing template:", err.Error())
+	}
+}
diff --git a/src/net/rpc/jsonrpc/all_test.go b/src/net/rpc/jsonrpc/all_test.go
new file mode 100644
index 0000000..e2ccdfc
--- /dev/null
+++ b/src/net/rpc/jsonrpc/all_test.go
@@ -0,0 +1,352 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jsonrpc
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/rpc"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+type Args struct {
+	A, B int
+}
+
+type Reply struct {
+	C int
+}
+
+type Arith int
+
+type ArithAddResp struct {
+	Id     any   `json:"id"`
+	Result Reply `json:"result"`
+	Error  any   `json:"error"`
+}
+
+func (t *Arith) Add(args *Args, reply *Reply) error {
+	reply.C = args.A + args.B
+	return nil
+}
+
+func (t *Arith) Mul(args *Args, reply *Reply) error {
+	reply.C = args.A * args.B
+	return nil
+}
+
+func (t *Arith) Div(args *Args, reply *Reply) error {
+	if args.B == 0 {
+		return errors.New("divide by zero")
+	}
+	reply.C = args.A / args.B
+	return nil
+}
+
+func (t *Arith) Error(args *Args, reply *Reply) error {
+	panic("ERROR")
+}
+
+type BuiltinTypes struct{}
+
+func (BuiltinTypes) Map(i int, reply *map[int]int) error {
+	(*reply)[i] = i
+	return nil
+}
+
+func (BuiltinTypes) Slice(i int, reply *[]int) error {
+	*reply = append(*reply, i)
+	return nil
+}
+
+func (BuiltinTypes) Array(i int, reply *[1]int) error {
+	(*reply)[0] = i
+	return nil
+}
+
+func init() {
+	rpc.Register(new(Arith))
+	rpc.Register(BuiltinTypes{})
+}
+
+func TestServerNoParams(t *testing.T) {
+	cli, srv := net.Pipe()
+	defer cli.Close()
+	go ServeConn(srv)
+	dec := json.NewDecoder(cli)
+
+	fmt.Fprintf(cli, `{"method": "Arith.Add", "id": "123"}`)
+	var resp ArithAddResp
+	if err := dec.Decode(&resp); err != nil {
+		t.Fatalf("Decode after no params: %s", err)
+	}
+	if resp.Error == nil {
+		t.Fatalf("Expected error, got nil")
+	}
+}
+
+func TestServerEmptyMessage(t *testing.T) {
+	cli, srv := net.Pipe()
+	defer cli.Close()
+	go ServeConn(srv)
+	dec := json.NewDecoder(cli)
+
+	fmt.Fprintf(cli, "{}")
+	var resp ArithAddResp
+	if err := dec.Decode(&resp); err != nil {
+		t.Fatalf("Decode after empty: %s", err)
+	}
+	if resp.Error == nil {
+		t.Fatalf("Expected error, got nil")
+	}
+}
+
+func TestServer(t *testing.T) {
+	cli, srv := net.Pipe()
+	defer cli.Close()
+	go ServeConn(srv)
+	dec := json.NewDecoder(cli)
+
+	// Send hand-coded requests to server, parse responses.
+	for i := 0; i < 10; i++ {
+		fmt.Fprintf(cli, `{"method": "Arith.Add", "id": "\u%04d", "params": [{"A": %d, "B": %d}]}`, i, i, i+1)
+		var resp ArithAddResp
+		err := dec.Decode(&resp)
+		if err != nil {
+			t.Fatalf("Decode: %s", err)
+		}
+		if resp.Error != nil {
+			t.Fatalf("resp.Error: %s", resp.Error)
+		}
+		if resp.Id.(string) != string(rune(i)) {
+			t.Fatalf("resp: bad id %q want %q", resp.Id.(string), string(rune(i)))
+		}
+		if resp.Result.C != 2*i+1 {
+			t.Fatalf("resp: bad result: %d+%d=%d", i, i+1, resp.Result.C)
+		}
+	}
+}
+
+func TestClient(t *testing.T) {
+	// Assume server is okay (TestServer is above).
+	// Test client against server.
+	cli, srv := net.Pipe()
+	go ServeConn(srv)
+
+	client := NewClient(cli)
+	defer client.Close()
+
+	// Synchronous calls
+	args := &Args{7, 8}
+	reply := new(Reply)
+	err := client.Call("Arith.Add", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: got %d expected %d", reply.C, args.A+args.B)
+	}
+
+	args = &Args{7, 8}
+	reply = new(Reply)
+	err = client.Call("Arith.Mul", args, reply)
+	if err != nil {
+		t.Errorf("Mul: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A*args.B {
+		t.Errorf("Mul: got %d expected %d", reply.C, args.A*args.B)
+	}
+
+	// Out of order.
+	args = &Args{7, 8}
+	mulReply := new(Reply)
+	mulCall := client.Go("Arith.Mul", args, mulReply, nil)
+	addReply := new(Reply)
+	addCall := client.Go("Arith.Add", args, addReply, nil)
+
+	addCall = <-addCall.Done
+	if addCall.Error != nil {
+		t.Errorf("Add: expected no error but got string %q", addCall.Error.Error())
+	}
+	if addReply.C != args.A+args.B {
+		t.Errorf("Add: got %d expected %d", addReply.C, args.A+args.B)
+	}
+
+	mulCall = <-mulCall.Done
+	if mulCall.Error != nil {
+		t.Errorf("Mul: expected no error but got string %q", mulCall.Error.Error())
+	}
+	if mulReply.C != args.A*args.B {
+		t.Errorf("Mul: got %d expected %d", mulReply.C, args.A*args.B)
+	}
+
+	// Error test
+	args = &Args{7, 0}
+	reply = new(Reply)
+	err = client.Call("Arith.Div", args, reply)
+	// expect an error: zero divide
+	if err == nil {
+		t.Error("Div: expected error")
+	} else if err.Error() != "divide by zero" {
+		t.Error("Div: expected divide by zero error; got", err)
+	}
+}
+
+func TestBuiltinTypes(t *testing.T) {
+	cli, srv := net.Pipe()
+	go ServeConn(srv)
+
+	client := NewClient(cli)
+	defer client.Close()
+
+	// Map
+	arg := 7
+	replyMap := map[int]int{}
+	err := client.Call("BuiltinTypes.Map", arg, &replyMap)
+	if err != nil {
+		t.Errorf("Map: expected no error but got string %q", err.Error())
+	}
+	if replyMap[arg] != arg {
+		t.Errorf("Map: expected %d got %d", arg, replyMap[arg])
+	}
+
+	// Slice
+	replySlice := []int{}
+	err = client.Call("BuiltinTypes.Slice", arg, &replySlice)
+	if err != nil {
+		t.Errorf("Slice: expected no error but got string %q", err.Error())
+	}
+	if e := []int{arg}; !reflect.DeepEqual(replySlice, e) {
+		t.Errorf("Slice: expected %v got %v", e, replySlice)
+	}
+
+	// Array
+	replyArray := [1]int{}
+	err = client.Call("BuiltinTypes.Array", arg, &replyArray)
+	if err != nil {
+		t.Errorf("Array: expected no error but got string %q", err.Error())
+	}
+	if e := [1]int{arg}; !reflect.DeepEqual(replyArray, e) {
+		t.Errorf("Array: expected %v got %v", e, replyArray)
+	}
+}
+
+func TestMalformedInput(t *testing.T) {
+	cli, srv := net.Pipe()
+	go cli.Write([]byte(`{id:1}`)) // invalid json
+	ServeConn(srv)                 // must return, not loop
+}
+
+func TestMalformedOutput(t *testing.T) {
+	cli, srv := net.Pipe()
+	go srv.Write([]byte(`{"id":0,"result":null,"error":null}`))
+	go io.ReadAll(srv)
+
+	client := NewClient(cli)
+	defer client.Close()
+
+	args := &Args{7, 8}
+	reply := new(Reply)
+	err := client.Call("Arith.Add", args, reply)
+	if err == nil {
+		t.Error("expected error")
+	}
+}
+
+func TestServerErrorHasNullResult(t *testing.T) {
+	var out strings.Builder
+	sc := NewServerCodec(struct {
+		io.Reader
+		io.Writer
+		io.Closer
+	}{
+		Reader: strings.NewReader(`{"method": "Arith.Add", "id": "123", "params": []}`),
+		Writer: &out,
+		Closer: io.NopCloser(nil),
+	})
+	r := new(rpc.Request)
+	if err := sc.ReadRequestHeader(r); err != nil {
+		t.Fatal(err)
+	}
+	const valueText = "the value we don't want to see"
+	const errorText = "some error"
+	err := sc.WriteResponse(&rpc.Response{
+		ServiceMethod: "Method",
+		Seq:           1,
+		Error:         errorText,
+	}, valueText)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(out.String(), errorText) {
+		t.Fatalf("Response didn't contain expected error %q: %s", errorText, &out)
+	}
+	if strings.Contains(out.String(), valueText) {
+		t.Errorf("Response contains both an error and value: %s", &out)
+	}
+}
+
+func TestUnexpectedError(t *testing.T) {
+	cli, srv := myPipe()
+	go cli.PipeWriter.CloseWithError(errors.New("unexpected error!")) // reader will get this error
+	ServeConn(srv)                                                    // must return, not loop
+}
+
+// Copied from package net.
+func myPipe() (*pipe, *pipe) {
+	r1, w1 := io.Pipe()
+	r2, w2 := io.Pipe()
+
+	return &pipe{r1, w2}, &pipe{r2, w1}
+}
+
+type pipe struct {
+	*io.PipeReader
+	*io.PipeWriter
+}
+
+type pipeAddr int
+
+func (pipeAddr) Network() string {
+	return "pipe"
+}
+
+func (pipeAddr) String() string {
+	return "pipe"
+}
+
+func (p *pipe) Close() error {
+	err := p.PipeReader.Close()
+	err1 := p.PipeWriter.Close()
+	if err == nil {
+		err = err1
+	}
+	return err
+}
+
+func (p *pipe) LocalAddr() net.Addr {
+	return pipeAddr(0)
+}
+
+func (p *pipe) RemoteAddr() net.Addr {
+	return pipeAddr(0)
+}
+
+func (p *pipe) SetTimeout(nsec int64) error {
+	return errors.New("net.Pipe does not support timeouts")
+}
+
+func (p *pipe) SetReadTimeout(nsec int64) error {
+	return errors.New("net.Pipe does not support timeouts")
+}
+
+func (p *pipe) SetWriteTimeout(nsec int64) error {
+	return errors.New("net.Pipe does not support timeouts")
+}
diff --git a/src/net/rpc/jsonrpc/client.go b/src/net/rpc/jsonrpc/client.go
new file mode 100644
index 0000000..c473017
--- /dev/null
+++ b/src/net/rpc/jsonrpc/client.go
@@ -0,0 +1,124 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package jsonrpc implements a JSON-RPC 1.0 ClientCodec and ServerCodec
+// for the rpc package.
+// For JSON-RPC 2.0 support, see https://godoc.org/?q=json-rpc+2.0
+package jsonrpc
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"net/rpc"
+	"sync"
+)
+
+type clientCodec struct {
+	dec *json.Decoder // for reading JSON values
+	enc *json.Encoder // for writing JSON values
+	c   io.Closer
+
+	// temporary work space
+	req  clientRequest
+	resp clientResponse
+
+	// JSON-RPC responses include the request id but not the request method.
+	// Package rpc expects both.
+	// We save the request method in pending when sending a request
+	// and then look it up by request ID when filling out the rpc Response.
+	mutex   sync.Mutex        // protects pending
+	pending map[uint64]string // map request id to method name
+}
+
+// NewClientCodec returns a new rpc.ClientCodec using JSON-RPC on conn.
+func NewClientCodec(conn io.ReadWriteCloser) rpc.ClientCodec {
+	return &clientCodec{
+		dec:     json.NewDecoder(conn),
+		enc:     json.NewEncoder(conn),
+		c:       conn,
+		pending: make(map[uint64]string),
+	}
+}
+
+type clientRequest struct {
+	Method string `json:"method"`
+	Params [1]any `json:"params"`
+	Id     uint64 `json:"id"`
+}
+
+func (c *clientCodec) WriteRequest(r *rpc.Request, param any) error {
+	c.mutex.Lock()
+	c.pending[r.Seq] = r.ServiceMethod
+	c.mutex.Unlock()
+	c.req.Method = r.ServiceMethod
+	c.req.Params[0] = param
+	c.req.Id = r.Seq
+	return c.enc.Encode(&c.req)
+}
+
+type clientResponse struct {
+	Id     uint64           `json:"id"`
+	Result *json.RawMessage `json:"result"`
+	Error  any              `json:"error"`
+}
+
+func (r *clientResponse) reset() {
+	r.Id = 0
+	r.Result = nil
+	r.Error = nil
+}
+
+func (c *clientCodec) ReadResponseHeader(r *rpc.Response) error {
+	c.resp.reset()
+	if err := c.dec.Decode(&c.resp); err != nil {
+		return err
+	}
+
+	c.mutex.Lock()
+	r.ServiceMethod = c.pending[c.resp.Id]
+	delete(c.pending, c.resp.Id)
+	c.mutex.Unlock()
+
+	r.Error = ""
+	r.Seq = c.resp.Id
+	if c.resp.Error != nil || c.resp.Result == nil {
+		x, ok := c.resp.Error.(string)
+		if !ok {
+			return fmt.Errorf("invalid error %v", c.resp.Error)
+		}
+		if x == "" {
+			x = "unspecified error"
+		}
+		r.Error = x
+	}
+	return nil
+}
+
+func (c *clientCodec) ReadResponseBody(x any) error {
+	if x == nil {
+		return nil
+	}
+	return json.Unmarshal(*c.resp.Result, x)
+}
+
+func (c *clientCodec) Close() error {
+	return c.c.Close()
+}
+
+// NewClient returns a new rpc.Client to handle requests to the
+// set of services at the other end of the connection.
+func NewClient(conn io.ReadWriteCloser) *rpc.Client {
+	return rpc.NewClientWithCodec(NewClientCodec(conn))
+}
+
+// Dial connects to a JSON-RPC server at the specified network address.
+func Dial(network, address string) (*rpc.Client, error) {
+	conn, err := net.Dial(network, address)
+	if err != nil {
+		return nil, err
+	}
+	return NewClient(conn), err
+}
diff --git a/src/net/rpc/jsonrpc/server.go b/src/net/rpc/jsonrpc/server.go
new file mode 100644
index 0000000..3ee4ddf
--- /dev/null
+++ b/src/net/rpc/jsonrpc/server.go
@@ -0,0 +1,134 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jsonrpc
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"net/rpc"
+	"sync"
+)
+
+var errMissingParams = errors.New("jsonrpc: request body missing params")
+
+type serverCodec struct {
+	dec *json.Decoder // for reading JSON values
+	enc *json.Encoder // for writing JSON values
+	c   io.Closer
+
+	// temporary work space
+	req serverRequest
+
+	// JSON-RPC clients can use arbitrary json values as request IDs.
+	// Package rpc expects uint64 request IDs.
+	// We assign uint64 sequence numbers to incoming requests
+	// but save the original request ID in the pending map.
+	// When rpc responds, we use the sequence number in
+	// the response to find the original request ID.
+	mutex   sync.Mutex // protects seq, pending
+	seq     uint64
+	pending map[uint64]*json.RawMessage
+}
+
+// NewServerCodec returns a new rpc.ServerCodec using JSON-RPC on conn.
+func NewServerCodec(conn io.ReadWriteCloser) rpc.ServerCodec {
+	return &serverCodec{
+		dec:     json.NewDecoder(conn),
+		enc:     json.NewEncoder(conn),
+		c:       conn,
+		pending: make(map[uint64]*json.RawMessage),
+	}
+}
+
+type serverRequest struct {
+	Method string           `json:"method"`
+	Params *json.RawMessage `json:"params"`
+	Id     *json.RawMessage `json:"id"`
+}
+
+func (r *serverRequest) reset() {
+	r.Method = ""
+	r.Params = nil
+	r.Id = nil
+}
+
+type serverResponse struct {
+	Id     *json.RawMessage `json:"id"`
+	Result any              `json:"result"`
+	Error  any              `json:"error"`
+}
+
+func (c *serverCodec) ReadRequestHeader(r *rpc.Request) error {
+	c.req.reset()
+	if err := c.dec.Decode(&c.req); err != nil {
+		return err
+	}
+	r.ServiceMethod = c.req.Method
+
+	// JSON request id can be any JSON value;
+	// RPC package expects uint64.  Translate to
+	// internal uint64 and save JSON on the side.
+	c.mutex.Lock()
+	c.seq++
+	c.pending[c.seq] = c.req.Id
+	c.req.Id = nil
+	r.Seq = c.seq
+	c.mutex.Unlock()
+
+	return nil
+}
+
+func (c *serverCodec) ReadRequestBody(x any) error {
+	if x == nil {
+		return nil
+	}
+	if c.req.Params == nil {
+		return errMissingParams
+	}
+	// JSON params is array value.
+	// RPC params is struct.
+	// Unmarshal into array containing struct for now.
+	// Should think about making RPC more general.
+	var params [1]any
+	params[0] = x
+	return json.Unmarshal(*c.req.Params, &params)
+}
+
+var null = json.RawMessage([]byte("null"))
+
+func (c *serverCodec) WriteResponse(r *rpc.Response, x any) error {
+	c.mutex.Lock()
+	b, ok := c.pending[r.Seq]
+	if !ok {
+		c.mutex.Unlock()
+		return errors.New("invalid sequence number in response")
+	}
+	delete(c.pending, r.Seq)
+	c.mutex.Unlock()
+
+	if b == nil {
+		// Invalid request so no id. Use JSON null.
+		b = &null
+	}
+	resp := serverResponse{Id: b}
+	if r.Error == "" {
+		resp.Result = x
+	} else {
+		resp.Error = r.Error
+	}
+	return c.enc.Encode(resp)
+}
+
+func (c *serverCodec) Close() error {
+	return c.c.Close()
+}
+
+// ServeConn runs the JSON-RPC server on a single connection.
+// ServeConn blocks, serving the connection until the client hangs up.
+// The caller typically invokes ServeConn in a go statement.
+func ServeConn(conn io.ReadWriteCloser) {
+	rpc.ServeCodec(NewServerCodec(conn))
+}
diff --git a/src/net/rpc/server.go b/src/net/rpc/server.go
new file mode 100644
index 0000000..109ebba
--- /dev/null
+++ b/src/net/rpc/server.go
@@ -0,0 +1,725 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package rpc provides access to the exported methods of an object across a
+network or other I/O connection.  A server registers an object, making it visible
+as a service with the name of the type of the object.  After registration, exported
+methods of the object will be accessible remotely.  A server may register multiple
+objects (services) of different types but it is an error to register multiple
+objects of the same type.
+
+Only methods that satisfy these criteria will be made available for remote access;
+other methods will be ignored:
+
+  - the method's type is exported.
+  - the method is exported.
+  - the method has two arguments, both exported (or builtin) types.
+  - the method's second argument is a pointer.
+  - the method has return type error.
+
+In effect, the method must look schematically like
+
+	func (t *T) MethodName(argType T1, replyType *T2) error
+
+where T1 and T2 can be marshaled by encoding/gob.
+These requirements apply even if a different codec is used.
+(In the future, these requirements may soften for custom codecs.)
+
+The method's first argument represents the arguments provided by the caller; the
+second argument represents the result parameters to be returned to the caller.
+The method's return value, if non-nil, is passed back as a string that the client
+sees as if created by errors.New.  If an error is returned, the reply parameter
+will not be sent back to the client.
+
+The server may handle requests on a single connection by calling ServeConn.  More
+typically it will create a network listener and call Accept or, for an HTTP
+listener, HandleHTTP and http.Serve.
+
+A client wishing to use the service establishes a connection and then invokes
+NewClient on the connection.  The convenience function Dial (DialHTTP) performs
+both steps for a raw network connection (an HTTP connection).  The resulting
+Client object has two methods, Call and Go, that specify the service and method to
+call, a pointer containing the arguments, and a pointer to receive the result
+parameters.
+
+The Call method waits for the remote call to complete while the Go method
+launches the call asynchronously and signals completion using the Call
+structure's Done channel.
+
+Unless an explicit codec is set up, package encoding/gob is used to
+transport the data.
+
+Here is a simple example.  A server wishes to export an object of type Arith:
+
+	package server
+
+	import "errors"
+
+	type Args struct {
+		A, B int
+	}
+
+	type Quotient struct {
+		Quo, Rem int
+	}
+
+	type Arith int
+
+	func (t *Arith) Multiply(args *Args, reply *int) error {
+		*reply = args.A * args.B
+		return nil
+	}
+
+	func (t *Arith) Divide(args *Args, quo *Quotient) error {
+		if args.B == 0 {
+			return errors.New("divide by zero")
+		}
+		quo.Quo = args.A / args.B
+		quo.Rem = args.A % args.B
+		return nil
+	}
+
+The server calls (for HTTP service):
+
+	arith := new(Arith)
+	rpc.Register(arith)
+	rpc.HandleHTTP()
+	l, e := net.Listen("tcp", ":1234")
+	if e != nil {
+		log.Fatal("listen error:", e)
+	}
+	go http.Serve(l, nil)
+
+At this point, clients can see a service "Arith" with methods "Arith.Multiply" and
+"Arith.Divide".  To invoke one, a client first dials the server:
+
+	client, err := rpc.DialHTTP("tcp", serverAddress + ":1234")
+	if err != nil {
+		log.Fatal("dialing:", err)
+	}
+
+Then it can make a remote call:
+
+	// Synchronous call
+	args := &server.Args{7,8}
+	var reply int
+	err = client.Call("Arith.Multiply", args, &reply)
+	if err != nil {
+		log.Fatal("arith error:", err)
+	}
+	fmt.Printf("Arith: %d*%d=%d", args.A, args.B, reply)
+
+or
+
+	// Asynchronous call
+	quotient := new(Quotient)
+	divCall := client.Go("Arith.Divide", args, quotient, nil)
+	replyCall := <-divCall.Done	// will be equal to divCall
+	// check errors, print, etc.
+
+A server implementation will often provide a simple, type-safe wrapper for the
+client.
+
+The net/rpc package is frozen and is not accepting new features.
+*/
+package rpc
+
+import (
+	"bufio"
+	"encoding/gob"
+	"errors"
+	"go/token"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"reflect"
+	"strings"
+	"sync"
+)
+
+const (
+	// Defaults used by HandleHTTP
+	DefaultRPCPath   = "/_goRPC_"
+	DefaultDebugPath = "/debug/rpc"
+)
+
+// Precompute the reflect type for error. Can't use error directly
+// because Typeof takes an empty interface value. This is annoying.
+var typeOfError = reflect.TypeOf((*error)(nil)).Elem()
+
+type methodType struct {
+	sync.Mutex // protects counters
+	method     reflect.Method
+	ArgType    reflect.Type
+	ReplyType  reflect.Type
+	numCalls   uint
+}
+
+type service struct {
+	name   string                 // name of service
+	rcvr   reflect.Value          // receiver of methods for the service
+	typ    reflect.Type           // type of the receiver
+	method map[string]*methodType // registered methods
+}
+
+// Request is a header written before every RPC call. It is used internally
+// but documented here as an aid to debugging, such as when analyzing
+// network traffic.
+type Request struct {
+	ServiceMethod string   // format: "Service.Method"
+	Seq           uint64   // sequence number chosen by client
+	next          *Request // for free list in Server
+}
+
+// Response is a header written before every RPC return. It is used internally
+// but documented here as an aid to debugging, such as when analyzing
+// network traffic.
+type Response struct {
+	ServiceMethod string    // echoes that of the Request
+	Seq           uint64    // echoes that of the request
+	Error         string    // error, if any.
+	next          *Response // for free list in Server
+}
+
+// Server represents an RPC Server.
+type Server struct {
+	serviceMap sync.Map   // map[string]*service
+	reqLock    sync.Mutex // protects freeReq
+	freeReq    *Request
+	respLock   sync.Mutex // protects freeResp
+	freeResp   *Response
+}
+
+// NewServer returns a new Server.
+func NewServer() *Server {
+	return &Server{}
+}
+
+// DefaultServer is the default instance of *Server.
+var DefaultServer = NewServer()
+
+// Is this type exported or a builtin?
+func isExportedOrBuiltinType(t reflect.Type) bool {
+	for t.Kind() == reflect.Pointer {
+		t = t.Elem()
+	}
+	// PkgPath will be non-empty even for an exported type,
+	// so we need to check the type name as well.
+	return token.IsExported(t.Name()) || t.PkgPath() == ""
+}
+
+// Register publishes in the server the set of methods of the
+// receiver value that satisfy the following conditions:
+//   - exported method of exported type
+//   - two arguments, both of exported type
+//   - the second argument is a pointer
+//   - one return value, of type error
+//
+// It returns an error if the receiver is not an exported type or has
+// no suitable methods. It also logs the error using package log.
+// The client accesses each method using a string of the form "Type.Method",
+// where Type is the receiver's concrete type.
+func (server *Server) Register(rcvr any) error {
+	return server.register(rcvr, "", false)
+}
+
+// RegisterName is like Register but uses the provided name for the type
+// instead of the receiver's concrete type.
+func (server *Server) RegisterName(name string, rcvr any) error {
+	return server.register(rcvr, name, true)
+}
+
+// logRegisterError specifies whether to log problems during method registration.
+// To debug registration, recompile the package with this set to true.
+const logRegisterError = false
+
+func (server *Server) register(rcvr any, name string, useName bool) error {
+	s := new(service)
+	s.typ = reflect.TypeOf(rcvr)
+	s.rcvr = reflect.ValueOf(rcvr)
+	sname := name
+	if !useName {
+		sname = reflect.Indirect(s.rcvr).Type().Name()
+	}
+	if sname == "" {
+		s := "rpc.Register: no service name for type " + s.typ.String()
+		log.Print(s)
+		return errors.New(s)
+	}
+	if !useName && !token.IsExported(sname) {
+		s := "rpc.Register: type " + sname + " is not exported"
+		log.Print(s)
+		return errors.New(s)
+	}
+	s.name = sname
+
+	// Install the methods
+	s.method = suitableMethods(s.typ, logRegisterError)
+
+	if len(s.method) == 0 {
+		str := ""
+
+		// To help the user, see if a pointer receiver would work.
+		method := suitableMethods(reflect.PointerTo(s.typ), false)
+		if len(method) != 0 {
+			str = "rpc.Register: type " + sname + " has no exported methods of suitable type (hint: pass a pointer to value of that type)"
+		} else {
+			str = "rpc.Register: type " + sname + " has no exported methods of suitable type"
+		}
+		log.Print(str)
+		return errors.New(str)
+	}
+
+	if _, dup := server.serviceMap.LoadOrStore(sname, s); dup {
+		return errors.New("rpc: service already defined: " + sname)
+	}
+	return nil
+}
+
+// suitableMethods returns suitable Rpc methods of typ. It will log
+// errors if logErr is true.
+func suitableMethods(typ reflect.Type, logErr bool) map[string]*methodType {
+	methods := make(map[string]*methodType)
+	for m := 0; m < typ.NumMethod(); m++ {
+		method := typ.Method(m)
+		mtype := method.Type
+		mname := method.Name
+		// Method must be exported.
+		if !method.IsExported() {
+			continue
+		}
+		// Method needs three ins: receiver, *args, *reply.
+		if mtype.NumIn() != 3 {
+			if logErr {
+				log.Printf("rpc.Register: method %q has %d input parameters; needs exactly three\n", mname, mtype.NumIn())
+			}
+			continue
+		}
+		// First arg need not be a pointer.
+		argType := mtype.In(1)
+		if !isExportedOrBuiltinType(argType) {
+			if logErr {
+				log.Printf("rpc.Register: argument type of method %q is not exported: %q\n", mname, argType)
+			}
+			continue
+		}
+		// Second arg must be a pointer.
+		replyType := mtype.In(2)
+		if replyType.Kind() != reflect.Pointer {
+			if logErr {
+				log.Printf("rpc.Register: reply type of method %q is not a pointer: %q\n", mname, replyType)
+			}
+			continue
+		}
+		// Reply type must be exported.
+		if !isExportedOrBuiltinType(replyType) {
+			if logErr {
+				log.Printf("rpc.Register: reply type of method %q is not exported: %q\n", mname, replyType)
+			}
+			continue
+		}
+		// Method needs one out.
+		if mtype.NumOut() != 1 {
+			if logErr {
+				log.Printf("rpc.Register: method %q has %d output parameters; needs exactly one\n", mname, mtype.NumOut())
+			}
+			continue
+		}
+		// The return type of the method must be error.
+		if returnType := mtype.Out(0); returnType != typeOfError {
+			if logErr {
+				log.Printf("rpc.Register: return type of method %q is %q, must be error\n", mname, returnType)
+			}
+			continue
+		}
+		methods[mname] = &methodType{method: method, ArgType: argType, ReplyType: replyType}
+	}
+	return methods
+}
+
+// A value sent as a placeholder for the server's response value when the server
+// receives an invalid request. It is never decoded by the client since the Response
+// contains an error when it is used.
+var invalidRequest = struct{}{}
+
+func (server *Server) sendResponse(sending *sync.Mutex, req *Request, reply any, codec ServerCodec, errmsg string) {
+	resp := server.getResponse()
+	// Encode the response header
+	resp.ServiceMethod = req.ServiceMethod
+	if errmsg != "" {
+		resp.Error = errmsg
+		reply = invalidRequest
+	}
+	resp.Seq = req.Seq
+	sending.Lock()
+	err := codec.WriteResponse(resp, reply)
+	if debugLog && err != nil {
+		log.Println("rpc: writing response:", err)
+	}
+	sending.Unlock()
+	server.freeResponse(resp)
+}
+
+func (m *methodType) NumCalls() (n uint) {
+	m.Lock()
+	n = m.numCalls
+	m.Unlock()
+	return n
+}
+
+func (s *service) call(server *Server, sending *sync.Mutex, wg *sync.WaitGroup, mtype *methodType, req *Request, argv, replyv reflect.Value, codec ServerCodec) {
+	if wg != nil {
+		defer wg.Done()
+	}
+	mtype.Lock()
+	mtype.numCalls++
+	mtype.Unlock()
+	function := mtype.method.Func
+	// Invoke the method, providing a new value for the reply.
+	returnValues := function.Call([]reflect.Value{s.rcvr, argv, replyv})
+	// The return value for the method is an error.
+	errInter := returnValues[0].Interface()
+	errmsg := ""
+	if errInter != nil {
+		errmsg = errInter.(error).Error()
+	}
+	server.sendResponse(sending, req, replyv.Interface(), codec, errmsg)
+	server.freeRequest(req)
+}
+
+type gobServerCodec struct {
+	rwc    io.ReadWriteCloser
+	dec    *gob.Decoder
+	enc    *gob.Encoder
+	encBuf *bufio.Writer
+	closed bool
+}
+
+func (c *gobServerCodec) ReadRequestHeader(r *Request) error {
+	return c.dec.Decode(r)
+}
+
+func (c *gobServerCodec) ReadRequestBody(body any) error {
+	return c.dec.Decode(body)
+}
+
+func (c *gobServerCodec) WriteResponse(r *Response, body any) (err error) {
+	if err = c.enc.Encode(r); err != nil {
+		if c.encBuf.Flush() == nil {
+			// Gob couldn't encode the header. Should not happen, so if it does,
+			// shut down the connection to signal that the connection is broken.
+			log.Println("rpc: gob error encoding response:", err)
+			c.Close()
+		}
+		return
+	}
+	if err = c.enc.Encode(body); err != nil {
+		if c.encBuf.Flush() == nil {
+			// Was a gob problem encoding the body but the header has been written.
+			// Shut down the connection to signal that the connection is broken.
+			log.Println("rpc: gob error encoding body:", err)
+			c.Close()
+		}
+		return
+	}
+	return c.encBuf.Flush()
+}
+
+func (c *gobServerCodec) Close() error {
+	if c.closed {
+		// Only call c.rwc.Close once; otherwise the semantics are undefined.
+		return nil
+	}
+	c.closed = true
+	return c.rwc.Close()
+}
+
+// ServeConn runs the server on a single connection.
+// ServeConn blocks, serving the connection until the client hangs up.
+// The caller typically invokes ServeConn in a go statement.
+// ServeConn uses the gob wire format (see package gob) on the
+// connection. To use an alternate codec, use ServeCodec.
+// See NewClient's comment for information about concurrent access.
+func (server *Server) ServeConn(conn io.ReadWriteCloser) {
+	buf := bufio.NewWriter(conn)
+	srv := &gobServerCodec{
+		rwc:    conn,
+		dec:    gob.NewDecoder(conn),
+		enc:    gob.NewEncoder(buf),
+		encBuf: buf,
+	}
+	server.ServeCodec(srv)
+}
+
+// ServeCodec is like ServeConn but uses the specified codec to
+// decode requests and encode responses.
+func (server *Server) ServeCodec(codec ServerCodec) {
+	sending := new(sync.Mutex)
+	wg := new(sync.WaitGroup)
+	for {
+		service, mtype, req, argv, replyv, keepReading, err := server.readRequest(codec)
+		if err != nil {
+			if debugLog && err != io.EOF {
+				log.Println("rpc:", err)
+			}
+			if !keepReading {
+				break
+			}
+			// send a response if we actually managed to read a header.
+			if req != nil {
+				server.sendResponse(sending, req, invalidRequest, codec, err.Error())
+				server.freeRequest(req)
+			}
+			continue
+		}
+		wg.Add(1)
+		go service.call(server, sending, wg, mtype, req, argv, replyv, codec)
+	}
+	// We've seen that there are no more requests.
+	// Wait for responses to be sent before closing codec.
+	wg.Wait()
+	codec.Close()
+}
+
+// ServeRequest is like ServeCodec but synchronously serves a single request.
+// It does not close the codec upon completion.
+func (server *Server) ServeRequest(codec ServerCodec) error {
+	sending := new(sync.Mutex)
+	service, mtype, req, argv, replyv, keepReading, err := server.readRequest(codec)
+	if err != nil {
+		if !keepReading {
+			return err
+		}
+		// send a response if we actually managed to read a header.
+		if req != nil {
+			server.sendResponse(sending, req, invalidRequest, codec, err.Error())
+			server.freeRequest(req)
+		}
+		return err
+	}
+	service.call(server, sending, nil, mtype, req, argv, replyv, codec)
+	return nil
+}
+
+func (server *Server) getRequest() *Request {
+	server.reqLock.Lock()
+	req := server.freeReq
+	if req == nil {
+		req = new(Request)
+	} else {
+		server.freeReq = req.next
+		*req = Request{}
+	}
+	server.reqLock.Unlock()
+	return req
+}
+
+func (server *Server) freeRequest(req *Request) {
+	server.reqLock.Lock()
+	req.next = server.freeReq
+	server.freeReq = req
+	server.reqLock.Unlock()
+}
+
+func (server *Server) getResponse() *Response {
+	server.respLock.Lock()
+	resp := server.freeResp
+	if resp == nil {
+		resp = new(Response)
+	} else {
+		server.freeResp = resp.next
+		*resp = Response{}
+	}
+	server.respLock.Unlock()
+	return resp
+}
+
+func (server *Server) freeResponse(resp *Response) {
+	server.respLock.Lock()
+	resp.next = server.freeResp
+	server.freeResp = resp
+	server.respLock.Unlock()
+}
+
+func (server *Server) readRequest(codec ServerCodec) (service *service, mtype *methodType, req *Request, argv, replyv reflect.Value, keepReading bool, err error) {
+	service, mtype, req, keepReading, err = server.readRequestHeader(codec)
+	if err != nil {
+		if !keepReading {
+			return
+		}
+		// discard body
+		codec.ReadRequestBody(nil)
+		return
+	}
+
+	// Decode the argument value.
+	argIsValue := false // if true, need to indirect before calling.
+	if mtype.ArgType.Kind() == reflect.Pointer {
+		argv = reflect.New(mtype.ArgType.Elem())
+	} else {
+		argv = reflect.New(mtype.ArgType)
+		argIsValue = true
+	}
+	// argv guaranteed to be a pointer now.
+	if err = codec.ReadRequestBody(argv.Interface()); err != nil {
+		return
+	}
+	if argIsValue {
+		argv = argv.Elem()
+	}
+
+	replyv = reflect.New(mtype.ReplyType.Elem())
+
+	switch mtype.ReplyType.Elem().Kind() {
+	case reflect.Map:
+		replyv.Elem().Set(reflect.MakeMap(mtype.ReplyType.Elem()))
+	case reflect.Slice:
+		replyv.Elem().Set(reflect.MakeSlice(mtype.ReplyType.Elem(), 0, 0))
+	}
+	return
+}
+
+func (server *Server) readRequestHeader(codec ServerCodec) (svc *service, mtype *methodType, req *Request, keepReading bool, err error) {
+	// Grab the request header.
+	req = server.getRequest()
+	err = codec.ReadRequestHeader(req)
+	if err != nil {
+		req = nil
+		if err == io.EOF || err == io.ErrUnexpectedEOF {
+			return
+		}
+		err = errors.New("rpc: server cannot decode request: " + err.Error())
+		return
+	}
+
+	// We read the header successfully. If we see an error now,
+	// we can still recover and move on to the next request.
+	keepReading = true
+
+	dot := strings.LastIndex(req.ServiceMethod, ".")
+	if dot < 0 {
+		err = errors.New("rpc: service/method request ill-formed: " + req.ServiceMethod)
+		return
+	}
+	serviceName := req.ServiceMethod[:dot]
+	methodName := req.ServiceMethod[dot+1:]
+
+	// Look up the request.
+	svci, ok := server.serviceMap.Load(serviceName)
+	if !ok {
+		err = errors.New("rpc: can't find service " + req.ServiceMethod)
+		return
+	}
+	svc = svci.(*service)
+	mtype = svc.method[methodName]
+	if mtype == nil {
+		err = errors.New("rpc: can't find method " + req.ServiceMethod)
+	}
+	return
+}
+
+// Accept accepts connections on the listener and serves requests
+// for each incoming connection. Accept blocks until the listener
+// returns a non-nil error. The caller typically invokes Accept in a
+// go statement.
+func (server *Server) Accept(lis net.Listener) {
+	for {
+		conn, err := lis.Accept()
+		if err != nil {
+			log.Print("rpc.Serve: accept:", err.Error())
+			return
+		}
+		go server.ServeConn(conn)
+	}
+}
+
+// Register publishes the receiver's methods in the DefaultServer.
+func Register(rcvr any) error { return DefaultServer.Register(rcvr) }
+
+// RegisterName is like Register but uses the provided name for the type
+// instead of the receiver's concrete type.
+func RegisterName(name string, rcvr any) error {
+	return DefaultServer.RegisterName(name, rcvr)
+}
+
+// A ServerCodec implements reading of RPC requests and writing of
+// RPC responses for the server side of an RPC session.
+// The server calls ReadRequestHeader and ReadRequestBody in pairs
+// to read requests from the connection, and it calls WriteResponse to
+// write a response back. The server calls Close when finished with the
+// connection. ReadRequestBody may be called with a nil
+// argument to force the body of the request to be read and discarded.
+// See NewClient's comment for information about concurrent access.
+type ServerCodec interface {
+	ReadRequestHeader(*Request) error
+	ReadRequestBody(any) error
+	WriteResponse(*Response, any) error
+
+	// Close can be called multiple times and must be idempotent.
+	Close() error
+}
+
+// ServeConn runs the DefaultServer on a single connection.
+// ServeConn blocks, serving the connection until the client hangs up.
+// The caller typically invokes ServeConn in a go statement.
+// ServeConn uses the gob wire format (see package gob) on the
+// connection. To use an alternate codec, use ServeCodec.
+// See NewClient's comment for information about concurrent access.
+func ServeConn(conn io.ReadWriteCloser) {
+	DefaultServer.ServeConn(conn)
+}
+
+// ServeCodec is like ServeConn but uses the specified codec to
+// decode requests and encode responses.
+func ServeCodec(codec ServerCodec) {
+	DefaultServer.ServeCodec(codec)
+}
+
+// ServeRequest is like ServeCodec but synchronously serves a single request.
+// It does not close the codec upon completion.
+func ServeRequest(codec ServerCodec) error {
+	return DefaultServer.ServeRequest(codec)
+}
+
+// Accept accepts connections on the listener and serves requests
+// to DefaultServer for each incoming connection.
+// Accept blocks; the caller typically invokes it in a go statement.
+func Accept(lis net.Listener) { DefaultServer.Accept(lis) }
+
+// Can connect to RPC service using HTTP CONNECT to rpcPath.
+var connected = "200 Connected to Go RPC"
+
+// ServeHTTP implements an http.Handler that answers RPC requests.
+func (server *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	if req.Method != "CONNECT" {
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		io.WriteString(w, "405 must CONNECT\n")
+		return
+	}
+	conn, _, err := w.(http.Hijacker).Hijack()
+	if err != nil {
+		log.Print("rpc hijacking ", req.RemoteAddr, ": ", err.Error())
+		return
+	}
+	io.WriteString(conn, "HTTP/1.0 "+connected+"\n\n")
+	server.ServeConn(conn)
+}
+
+// HandleHTTP registers an HTTP handler for RPC messages on rpcPath,
+// and a debugging handler on debugPath.
+// It is still necessary to invoke http.Serve(), typically in a go statement.
+func (server *Server) HandleHTTP(rpcPath, debugPath string) {
+	http.Handle(rpcPath, server)
+	http.Handle(debugPath, debugHTTP{server})
+}
+
+// HandleHTTP registers an HTTP handler for RPC messages to DefaultServer
+// on DefaultRPCPath and a debugging handler on DefaultDebugPath.
+// It is still necessary to invoke http.Serve(), typically in a go statement.
+func HandleHTTP() {
+	DefaultServer.HandleHTTP(DefaultRPCPath, DefaultDebugPath)
+}
diff --git a/src/net/rpc/server_test.go b/src/net/rpc/server_test.go
new file mode 100644
index 0000000..dc5f5de
--- /dev/null
+++ b/src/net/rpc/server_test.go
@@ -0,0 +1,839 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package rpc
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http/httptest"
+	"reflect"
+	"runtime"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+var (
+	newServer                 *Server
+	serverAddr, newServerAddr string
+	httpServerAddr            string
+	once, newOnce, httpOnce   sync.Once
+)
+
+const (
+	newHttpPath = "/foo"
+)
+
+type Args struct {
+	A, B int
+}
+
+type Reply struct {
+	C int
+}
+
+type Arith int
+
+// Some of Arith's methods have value args, some have pointer args. That's deliberate.
+
+func (t *Arith) Add(args Args, reply *Reply) error {
+	reply.C = args.A + args.B
+	return nil
+}
+
+func (t *Arith) Mul(args *Args, reply *Reply) error {
+	reply.C = args.A * args.B
+	return nil
+}
+
+func (t *Arith) Div(args Args, reply *Reply) error {
+	if args.B == 0 {
+		return errors.New("divide by zero")
+	}
+	reply.C = args.A / args.B
+	return nil
+}
+
+func (t *Arith) String(args *Args, reply *string) error {
+	*reply = fmt.Sprintf("%d+%d=%d", args.A, args.B, args.A+args.B)
+	return nil
+}
+
+func (t *Arith) Scan(args string, reply *Reply) (err error) {
+	_, err = fmt.Sscan(args, &reply.C)
+	return
+}
+
+func (t *Arith) Error(args *Args, reply *Reply) error {
+	panic("ERROR")
+}
+
+func (t *Arith) SleepMilli(args *Args, reply *Reply) error {
+	time.Sleep(time.Duration(args.A) * time.Millisecond)
+	return nil
+}
+
+type hidden int
+
+func (t *hidden) Exported(args Args, reply *Reply) error {
+	reply.C = args.A + args.B
+	return nil
+}
+
+type Embed struct {
+	hidden
+}
+
+type BuiltinTypes struct{}
+
+func (BuiltinTypes) Map(args *Args, reply *map[int]int) error {
+	(*reply)[args.A] = args.B
+	return nil
+}
+
+func (BuiltinTypes) Slice(args *Args, reply *[]int) error {
+	*reply = append(*reply, args.A, args.B)
+	return nil
+}
+
+func (BuiltinTypes) Array(args *Args, reply *[2]int) error {
+	(*reply)[0] = args.A
+	(*reply)[1] = args.B
+	return nil
+}
+
+func listenTCP() (net.Listener, string) {
+	l, e := net.Listen("tcp", "127.0.0.1:0") // any available address
+	if e != nil {
+		log.Fatalf("net.Listen tcp :0: %v", e)
+	}
+	return l, l.Addr().String()
+}
+
+func startServer() {
+	Register(new(Arith))
+	Register(new(Embed))
+	RegisterName("net.rpc.Arith", new(Arith))
+	Register(BuiltinTypes{})
+
+	var l net.Listener
+	l, serverAddr = listenTCP()
+	log.Println("Test RPC server listening on", serverAddr)
+	go Accept(l)
+
+	HandleHTTP()
+	httpOnce.Do(startHttpServer)
+}
+
+func startNewServer() {
+	newServer = NewServer()
+	newServer.Register(new(Arith))
+	newServer.Register(new(Embed))
+	newServer.RegisterName("net.rpc.Arith", new(Arith))
+	newServer.RegisterName("newServer.Arith", new(Arith))
+
+	var l net.Listener
+	l, newServerAddr = listenTCP()
+	log.Println("NewServer test RPC server listening on", newServerAddr)
+	go newServer.Accept(l)
+
+	newServer.HandleHTTP(newHttpPath, "/bar")
+	httpOnce.Do(startHttpServer)
+}
+
+func startHttpServer() {
+	server := httptest.NewServer(nil)
+	httpServerAddr = server.Listener.Addr().String()
+	log.Println("Test HTTP RPC server listening on", httpServerAddr)
+}
+
+func TestRPC(t *testing.T) {
+	once.Do(startServer)
+	testRPC(t, serverAddr)
+	newOnce.Do(startNewServer)
+	testRPC(t, newServerAddr)
+	testNewServerRPC(t, newServerAddr)
+}
+
+func testRPC(t *testing.T, addr string) {
+	client, err := Dial("tcp", addr)
+	if err != nil {
+		t.Fatal("dialing", err)
+	}
+	defer client.Close()
+
+	// Synchronous calls
+	args := &Args{7, 8}
+	reply := new(Reply)
+	err = client.Call("Arith.Add", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+	}
+
+	// Methods exported from unexported embedded structs
+	args = &Args{7, 0}
+	reply = new(Reply)
+	err = client.Call("Embed.Exported", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+	}
+
+	// Nonexistent method
+	args = &Args{7, 0}
+	reply = new(Reply)
+	err = client.Call("Arith.BadOperation", args, reply)
+	// expect an error
+	if err == nil {
+		t.Error("BadOperation: expected error")
+	} else if !strings.HasPrefix(err.Error(), "rpc: can't find method ") {
+		t.Errorf("BadOperation: expected can't find method error; got %q", err)
+	}
+
+	// Unknown service
+	args = &Args{7, 8}
+	reply = new(Reply)
+	err = client.Call("Arith.Unknown", args, reply)
+	if err == nil {
+		t.Error("expected error calling unknown service")
+	} else if !strings.Contains(err.Error(), "method") {
+		t.Error("expected error about method; got", err)
+	}
+
+	// Out of order.
+	args = &Args{7, 8}
+	mulReply := new(Reply)
+	mulCall := client.Go("Arith.Mul", args, mulReply, nil)
+	addReply := new(Reply)
+	addCall := client.Go("Arith.Add", args, addReply, nil)
+
+	addCall = <-addCall.Done
+	if addCall.Error != nil {
+		t.Errorf("Add: expected no error but got string %q", addCall.Error.Error())
+	}
+	if addReply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", addReply.C, args.A+args.B)
+	}
+
+	mulCall = <-mulCall.Done
+	if mulCall.Error != nil {
+		t.Errorf("Mul: expected no error but got string %q", mulCall.Error.Error())
+	}
+	if mulReply.C != args.A*args.B {
+		t.Errorf("Mul: expected %d got %d", mulReply.C, args.A*args.B)
+	}
+
+	// Error test
+	args = &Args{7, 0}
+	reply = new(Reply)
+	err = client.Call("Arith.Div", args, reply)
+	// expect an error: zero divide
+	if err == nil {
+		t.Error("Div: expected error")
+	} else if err.Error() != "divide by zero" {
+		t.Error("Div: expected divide by zero error; got", err)
+	}
+
+	// Bad type.
+	reply = new(Reply)
+	err = client.Call("Arith.Add", reply, reply) // args, reply would be the correct thing to use
+	if err == nil {
+		t.Error("expected error calling Arith.Add with wrong arg type")
+	} else if !strings.Contains(err.Error(), "type") {
+		t.Error("expected error about type; got", err)
+	}
+
+	// Non-struct argument
+	const Val = 12345
+	str := fmt.Sprint(Val)
+	reply = new(Reply)
+	err = client.Call("Arith.Scan", &str, reply)
+	if err != nil {
+		t.Errorf("Scan: expected no error but got string %q", err.Error())
+	} else if reply.C != Val {
+		t.Errorf("Scan: expected %d got %d", Val, reply.C)
+	}
+
+	// Non-struct reply
+	args = &Args{27, 35}
+	str = ""
+	err = client.Call("Arith.String", args, &str)
+	if err != nil {
+		t.Errorf("String: expected no error but got string %q", err.Error())
+	}
+	expect := fmt.Sprintf("%d+%d=%d", args.A, args.B, args.A+args.B)
+	if str != expect {
+		t.Errorf("String: expected %s got %s", expect, str)
+	}
+
+	args = &Args{7, 8}
+	reply = new(Reply)
+	err = client.Call("Arith.Mul", args, reply)
+	if err != nil {
+		t.Errorf("Mul: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A*args.B {
+		t.Errorf("Mul: expected %d got %d", reply.C, args.A*args.B)
+	}
+
+	// ServiceName contain "." character
+	args = &Args{7, 8}
+	reply = new(Reply)
+	err = client.Call("net.rpc.Arith.Add", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+	}
+}
+
+func testNewServerRPC(t *testing.T, addr string) {
+	client, err := Dial("tcp", addr)
+	if err != nil {
+		t.Fatal("dialing", err)
+	}
+	defer client.Close()
+
+	// Synchronous calls
+	args := &Args{7, 8}
+	reply := new(Reply)
+	err = client.Call("newServer.Arith.Add", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+	}
+}
+
+func TestHTTP(t *testing.T) {
+	once.Do(startServer)
+	testHTTPRPC(t, "")
+	newOnce.Do(startNewServer)
+	testHTTPRPC(t, newHttpPath)
+}
+
+func testHTTPRPC(t *testing.T, path string) {
+	var client *Client
+	var err error
+	if path == "" {
+		client, err = DialHTTP("tcp", httpServerAddr)
+	} else {
+		client, err = DialHTTPPath("tcp", httpServerAddr, path)
+	}
+	if err != nil {
+		t.Fatal("dialing", err)
+	}
+	defer client.Close()
+
+	// Synchronous calls
+	args := &Args{7, 8}
+	reply := new(Reply)
+	err = client.Call("Arith.Add", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+	}
+}
+
+func TestBuiltinTypes(t *testing.T) {
+	once.Do(startServer)
+
+	client, err := DialHTTP("tcp", httpServerAddr)
+	if err != nil {
+		t.Fatal("dialing", err)
+	}
+	defer client.Close()
+
+	// Map
+	args := &Args{7, 8}
+	replyMap := map[int]int{}
+	err = client.Call("BuiltinTypes.Map", args, &replyMap)
+	if err != nil {
+		t.Errorf("Map: expected no error but got string %q", err.Error())
+	}
+	if replyMap[args.A] != args.B {
+		t.Errorf("Map: expected %d got %d", args.B, replyMap[args.A])
+	}
+
+	// Slice
+	args = &Args{7, 8}
+	replySlice := []int{}
+	err = client.Call("BuiltinTypes.Slice", args, &replySlice)
+	if err != nil {
+		t.Errorf("Slice: expected no error but got string %q", err.Error())
+	}
+	if e := []int{args.A, args.B}; !reflect.DeepEqual(replySlice, e) {
+		t.Errorf("Slice: expected %v got %v", e, replySlice)
+	}
+
+	// Array
+	args = &Args{7, 8}
+	replyArray := [2]int{}
+	err = client.Call("BuiltinTypes.Array", args, &replyArray)
+	if err != nil {
+		t.Errorf("Array: expected no error but got string %q", err.Error())
+	}
+	if e := [2]int{args.A, args.B}; !reflect.DeepEqual(replyArray, e) {
+		t.Errorf("Array: expected %v got %v", e, replyArray)
+	}
+}
+
+// CodecEmulator provides a client-like api and a ServerCodec interface.
+// Can be used to test ServeRequest.
+type CodecEmulator struct {
+	server        *Server
+	serviceMethod string
+	args          *Args
+	reply         *Reply
+	err           error
+}
+
+func (codec *CodecEmulator) Call(serviceMethod string, args *Args, reply *Reply) error {
+	codec.serviceMethod = serviceMethod
+	codec.args = args
+	codec.reply = reply
+	codec.err = nil
+	var serverError error
+	if codec.server == nil {
+		serverError = ServeRequest(codec)
+	} else {
+		serverError = codec.server.ServeRequest(codec)
+	}
+	if codec.err == nil && serverError != nil {
+		codec.err = serverError
+	}
+	return codec.err
+}
+
+func (codec *CodecEmulator) ReadRequestHeader(req *Request) error {
+	req.ServiceMethod = codec.serviceMethod
+	req.Seq = 0
+	return nil
+}
+
+func (codec *CodecEmulator) ReadRequestBody(argv any) error {
+	if codec.args == nil {
+		return io.ErrUnexpectedEOF
+	}
+	*(argv.(*Args)) = *codec.args
+	return nil
+}
+
+func (codec *CodecEmulator) WriteResponse(resp *Response, reply any) error {
+	if resp.Error != "" {
+		codec.err = errors.New(resp.Error)
+	} else {
+		*codec.reply = *(reply.(*Reply))
+	}
+	return nil
+}
+
+func (codec *CodecEmulator) Close() error {
+	return nil
+}
+
+func TestServeRequest(t *testing.T) {
+	once.Do(startServer)
+	testServeRequest(t, nil)
+	newOnce.Do(startNewServer)
+	testServeRequest(t, newServer)
+}
+
+func testServeRequest(t *testing.T, server *Server) {
+	client := CodecEmulator{server: server}
+	defer client.Close()
+
+	args := &Args{7, 8}
+	reply := new(Reply)
+	err := client.Call("Arith.Add", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+	}
+
+	err = client.Call("Arith.Add", nil, reply)
+	if err == nil {
+		t.Errorf("expected error calling Arith.Add with nil arg")
+	}
+}
+
+type ReplyNotPointer int
+type ArgNotPublic int
+type ReplyNotPublic int
+type NeedsPtrType int
+type local struct{}
+
+func (t *ReplyNotPointer) ReplyNotPointer(args *Args, reply Reply) error {
+	return nil
+}
+
+func (t *ArgNotPublic) ArgNotPublic(args *local, reply *Reply) error {
+	return nil
+}
+
+func (t *ReplyNotPublic) ReplyNotPublic(args *Args, reply *local) error {
+	return nil
+}
+
+func (t *NeedsPtrType) NeedsPtrType(args *Args, reply *Reply) error {
+	return nil
+}
+
+// Check that registration handles lots of bad methods and a type with no suitable methods.
+func TestRegistrationError(t *testing.T) {
+	err := Register(new(ReplyNotPointer))
+	if err == nil {
+		t.Error("expected error registering ReplyNotPointer")
+	}
+	err = Register(new(ArgNotPublic))
+	if err == nil {
+		t.Error("expected error registering ArgNotPublic")
+	}
+	err = Register(new(ReplyNotPublic))
+	if err == nil {
+		t.Error("expected error registering ReplyNotPublic")
+	}
+	err = Register(NeedsPtrType(0))
+	if err == nil {
+		t.Error("expected error registering NeedsPtrType")
+	} else if !strings.Contains(err.Error(), "pointer") {
+		t.Error("expected hint when registering NeedsPtrType")
+	}
+}
+
+type WriteFailCodec int
+
+func (WriteFailCodec) WriteRequest(*Request, any) error {
+	// the panic caused by this error used to not unlock a lock.
+	return errors.New("fail")
+}
+
+func (WriteFailCodec) ReadResponseHeader(*Response) error {
+	select {}
+}
+
+func (WriteFailCodec) ReadResponseBody(any) error {
+	select {}
+}
+
+func (WriteFailCodec) Close() error {
+	return nil
+}
+
+func TestSendDeadlock(t *testing.T) {
+	client := NewClientWithCodec(WriteFailCodec(0))
+	defer client.Close()
+
+	done := make(chan bool)
+	go func() {
+		testSendDeadlock(client)
+		testSendDeadlock(client)
+		done <- true
+	}()
+	select {
+	case <-done:
+		return
+	case <-time.After(5 * time.Second):
+		t.Fatal("deadlock")
+	}
+}
+
+func testSendDeadlock(client *Client) {
+	defer func() {
+		recover()
+	}()
+	args := &Args{7, 8}
+	reply := new(Reply)
+	client.Call("Arith.Add", args, reply)
+}
+
+func dialDirect() (*Client, error) {
+	return Dial("tcp", serverAddr)
+}
+
+func dialHTTP() (*Client, error) {
+	return DialHTTP("tcp", httpServerAddr)
+}
+
+func countMallocs(dial func() (*Client, error), t *testing.T) float64 {
+	once.Do(startServer)
+	client, err := dial()
+	if err != nil {
+		t.Fatal("error dialing", err)
+	}
+	defer client.Close()
+
+	args := &Args{7, 8}
+	reply := new(Reply)
+	return testing.AllocsPerRun(100, func() {
+		err := client.Call("Arith.Add", args, reply)
+		if err != nil {
+			t.Errorf("Add: expected no error but got string %q", err.Error())
+		}
+		if reply.C != args.A+args.B {
+			t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+		}
+	})
+}
+
+func TestCountMallocs(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping malloc count in short mode")
+	}
+	if runtime.GOMAXPROCS(0) > 1 {
+		t.Skip("skipping; GOMAXPROCS>1")
+	}
+	fmt.Printf("mallocs per rpc round trip: %v\n", countMallocs(dialDirect, t))
+}
+
+func TestCountMallocsOverHTTP(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping malloc count in short mode")
+	}
+	if runtime.GOMAXPROCS(0) > 1 {
+		t.Skip("skipping; GOMAXPROCS>1")
+	}
+	fmt.Printf("mallocs per HTTP rpc round trip: %v\n", countMallocs(dialHTTP, t))
+}
+
+type writeCrasher struct {
+	done chan bool
+}
+
+func (writeCrasher) Close() error {
+	return nil
+}
+
+func (w *writeCrasher) Read(p []byte) (int, error) {
+	<-w.done
+	return 0, io.EOF
+}
+
+func (writeCrasher) Write(p []byte) (int, error) {
+	return 0, errors.New("fake write failure")
+}
+
+func TestClientWriteError(t *testing.T) {
+	w := &writeCrasher{done: make(chan bool)}
+	c := NewClient(w)
+	defer c.Close()
+
+	res := false
+	err := c.Call("foo", 1, &res)
+	if err == nil {
+		t.Fatal("expected error")
+	}
+	if err.Error() != "fake write failure" {
+		t.Error("unexpected value of error:", err)
+	}
+	w.done <- true
+}
+
+func TestTCPClose(t *testing.T) {
+	once.Do(startServer)
+
+	client, err := dialHTTP()
+	if err != nil {
+		t.Fatalf("dialing: %v", err)
+	}
+	defer client.Close()
+
+	args := Args{17, 8}
+	var reply Reply
+	err = client.Call("Arith.Mul", args, &reply)
+	if err != nil {
+		t.Fatal("arith error:", err)
+	}
+	t.Logf("Arith: %d*%d=%d\n", args.A, args.B, reply)
+	if reply.C != args.A*args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A*args.B)
+	}
+}
+
+func TestErrorAfterClientClose(t *testing.T) {
+	once.Do(startServer)
+
+	client, err := dialHTTP()
+	if err != nil {
+		t.Fatalf("dialing: %v", err)
+	}
+	err = client.Close()
+	if err != nil {
+		t.Fatal("close error:", err)
+	}
+	err = client.Call("Arith.Add", &Args{7, 9}, new(Reply))
+	if err != ErrShutdown {
+		t.Errorf("Forever: expected ErrShutdown got %v", err)
+	}
+}
+
+// Tests the fix to issue 11221. Without the fix, this loops forever or crashes.
+func TestAcceptExitAfterListenerClose(t *testing.T) {
+	newServer := NewServer()
+	newServer.Register(new(Arith))
+	newServer.RegisterName("net.rpc.Arith", new(Arith))
+	newServer.RegisterName("newServer.Arith", new(Arith))
+
+	var l net.Listener
+	l, _ = listenTCP()
+	l.Close()
+	newServer.Accept(l)
+}
+
+func TestShutdown(t *testing.T) {
+	var l net.Listener
+	l, _ = listenTCP()
+	ch := make(chan net.Conn, 1)
+	go func() {
+		defer l.Close()
+		c, err := l.Accept()
+		if err != nil {
+			t.Error(err)
+		}
+		ch <- c
+	}()
+	c, err := net.Dial("tcp", l.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	c1 := <-ch
+	if c1 == nil {
+		t.Fatal(err)
+	}
+
+	newServer := NewServer()
+	newServer.Register(new(Arith))
+	go newServer.ServeConn(c1)
+
+	args := &Args{7, 8}
+	reply := new(Reply)
+	client := NewClient(c)
+	err = client.Call("Arith.Add", args, reply)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// On an unloaded system 10ms is usually enough to fail 100% of the time
+	// with a broken server. On a loaded system, a broken server might incorrectly
+	// be reported as passing, but we're OK with that kind of flakiness.
+	// If the code is correct, this test will never fail, regardless of timeout.
+	args.A = 10 // 10 ms
+	done := make(chan *Call, 1)
+	call := client.Go("Arith.SleepMilli", args, reply, done)
+	c.(*net.TCPConn).CloseWrite()
+	<-done
+	if call.Error != nil {
+		t.Fatal(err)
+	}
+}
+
+func benchmarkEndToEnd(dial func() (*Client, error), b *testing.B) {
+	once.Do(startServer)
+	client, err := dial()
+	if err != nil {
+		b.Fatal("error dialing:", err)
+	}
+	defer client.Close()
+
+	// Synchronous calls
+	args := &Args{7, 8}
+	b.ResetTimer()
+
+	b.RunParallel(func(pb *testing.PB) {
+		reply := new(Reply)
+		for pb.Next() {
+			err := client.Call("Arith.Add", args, reply)
+			if err != nil {
+				b.Fatalf("rpc error: Add: expected no error but got string %q", err.Error())
+			}
+			if reply.C != args.A+args.B {
+				b.Fatalf("rpc error: Add: expected %d got %d", reply.C, args.A+args.B)
+			}
+		}
+	})
+}
+
+func benchmarkEndToEndAsync(dial func() (*Client, error), b *testing.B) {
+	if b.N == 0 {
+		return
+	}
+	const MaxConcurrentCalls = 100
+	once.Do(startServer)
+	client, err := dial()
+	if err != nil {
+		b.Fatal("error dialing:", err)
+	}
+	defer client.Close()
+
+	// Asynchronous calls
+	args := &Args{7, 8}
+	procs := 4 * runtime.GOMAXPROCS(-1)
+	send := int32(b.N)
+	recv := int32(b.N)
+	var wg sync.WaitGroup
+	wg.Add(procs)
+	gate := make(chan bool, MaxConcurrentCalls)
+	res := make(chan *Call, MaxConcurrentCalls)
+	b.ResetTimer()
+
+	for p := 0; p < procs; p++ {
+		go func() {
+			for atomic.AddInt32(&send, -1) >= 0 {
+				gate <- true
+				reply := new(Reply)
+				client.Go("Arith.Add", args, reply, res)
+			}
+		}()
+		go func() {
+			for call := range res {
+				A := call.Args.(*Args).A
+				B := call.Args.(*Args).B
+				C := call.Reply.(*Reply).C
+				if A+B != C {
+					b.Errorf("incorrect reply: Add: expected %d got %d", A+B, C)
+					return
+				}
+				<-gate
+				if atomic.AddInt32(&recv, -1) == 0 {
+					close(res)
+				}
+			}
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+}
+
+func BenchmarkEndToEnd(b *testing.B) {
+	benchmarkEndToEnd(dialDirect, b)
+}
+
+func BenchmarkEndToEndHTTP(b *testing.B) {
+	benchmarkEndToEnd(dialHTTP, b)
+}
+
+func BenchmarkEndToEndAsync(b *testing.B) {
+	benchmarkEndToEndAsync(dialDirect, b)
+}
+
+func BenchmarkEndToEndAsyncHTTP(b *testing.B) {
+	benchmarkEndToEndAsync(dialHTTP, b)
+}