Update to go1.23.3

src/os/copy_test.go

@@ -0,0 +1,154 @@
+// Copyright 2024 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 os_test
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"math/rand/v2"
+	"net"
+	"os"
+	"runtime"
+	"sync"
+	"testing"
+
+	"golang.org/x/net/nettest"
+)
+
+// Exercise sendfile/splice fast paths with a moderately large file.
+//
+// https://go.dev/issue/70000
+
+func TestLargeCopyViaNetwork(t *testing.T) {
+	const size = 10 * 1024 * 1024
+	dir := t.TempDir()
+
+	src, err := os.Create(dir + "/src")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer src.Close()
+	if _, err := io.CopyN(src, newRandReader(), size); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := src.Seek(0, 0); err != nil {
+		t.Fatal(err)
+	}
+
+	dst, err := os.Create(dir + "/dst")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dst.Close()
+
+	client, server := createSocketPair(t, "tcp")
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		if n, err := io.Copy(dst, server); n != size || err != nil {
+			t.Errorf("copy to destination = %v, %v; want %v, nil", n, err, size)
+		}
+	}()
+	go func() {
+		defer wg.Done()
+		defer client.Close()
+		if n, err := io.Copy(client, src); n != size || err != nil {
+			t.Errorf("copy from source = %v, %v; want %v, nil", n, err, size)
+		}
+	}()
+	wg.Wait()
+
+	if _, err := dst.Seek(0, 0); err != nil {
+		t.Fatal(err)
+	}
+	if err := compareReaders(dst, io.LimitReader(newRandReader(), size)); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func compareReaders(a, b io.Reader) error {
+	bufa := make([]byte, 4096)
+	bufb := make([]byte, 4096)
+	for {
+		na, erra := io.ReadFull(a, bufa)
+		if erra != nil && erra != io.EOF {
+			return erra
+		}
+		nb, errb := io.ReadFull(b, bufb)
+		if errb != nil && errb != io.EOF {
+			return errb
+		}
+		if !bytes.Equal(bufa[:na], bufb[:nb]) {
+			return errors.New("contents mismatch")
+		}
+		if erra == io.EOF && errb == io.EOF {
+			break
+		}
+	}
+	return nil
+}
+
+type randReader struct {
+	rand *rand.Rand
+}
+
+func newRandReader() *randReader {
+	return &randReader{rand.New(rand.NewPCG(0, 0))}
+}
+
+func (r *randReader) Read(p []byte) (int, error) {
+	var v uint64
+	var n int
+	for i := range p {
+		if n == 0 {
+			v = r.rand.Uint64()
+			n = 8
+		}
+		p[i] = byte(v & 0xff)
+		v >>= 8
+		n--
+	}
+	return len(p), nil
+}
+
+func createSocketPair(t *testing.T, proto string) (client, server net.Conn) {
+	t.Helper()
+	if !nettest.TestableNetwork(proto) {
+		t.Skipf("%s does not support %q", runtime.GOOS, proto)
+	}
+
+	ln, err := nettest.NewLocalListener(proto)
+	if err != nil {
+		t.Fatalf("NewLocalListener error: %v", err)
+	}
+	t.Cleanup(func() {
+		if ln != nil {
+			ln.Close()
+		}
+		if client != nil {
+			client.Close()
+		}
+		if server != nil {
+			server.Close()
+		}
+	})
+	ch := make(chan struct{})
+	go func() {
+		var err error
+		server, err = ln.Accept()
+		if err != nil {
+			t.Errorf("Accept new connection error: %v", err)
+		}
+		ch <- struct{}{}
+	}()
+	client, err = net.Dial(proto, ln.Addr().String())
+	<-ch
+	if err != nil {
+		t.Fatalf("Dial new connection error: %v", err)
+	}
+	return client, server
+}