golang.org/x/sys@v0.20.1-0.20240517151509-673e0f94c16d/unix/sendfile_test.go (about)

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build (darwin && amd64) || dragonfly || freebsd || linux || solaris
     6  
     7  package unix_test
     8  
     9  import (
    10  	"io"
    11  	"net"
    12  	"os"
    13  	"path/filepath"
    14  	"testing"
    15  
    16  	"golang.org/x/sys/unix"
    17  )
    18  
    19  func TestSendfile(t *testing.T) {
    20  	// Set up source data file.
    21  	name := filepath.Join(t.TempDir(), "source")
    22  	const contents = "contents"
    23  	err := os.WriteFile(name, []byte(contents), 0666)
    24  	if err != nil {
    25  		t.Fatal(err)
    26  	}
    27  
    28  	done := make(chan bool)
    29  
    30  	// Start server listening on a socket.
    31  	ln, err := net.Listen("tcp", "127.0.0.1:0")
    32  	if err != nil {
    33  		t.Skipf("listen failed: %s\n", err)
    34  	}
    35  	defer ln.Close()
    36  	go func() {
    37  		conn, err := ln.Accept()
    38  		if err != nil {
    39  			t.Errorf("failed to accept: %v", err)
    40  			return
    41  		}
    42  		defer conn.Close()
    43  		b, err := io.ReadAll(conn)
    44  		if err != nil {
    45  			t.Errorf("failed to read: %v", err)
    46  			return
    47  		}
    48  		if string(b) != contents {
    49  			t.Errorf("contents not transmitted: got %s (len=%d), want %s", string(b), len(b), contents)
    50  		}
    51  		done <- true
    52  	}()
    53  
    54  	// Open source file.
    55  	src, err := os.Open(name)
    56  	if err != nil {
    57  		t.Fatal(err)
    58  	}
    59  
    60  	// Send source file to server.
    61  	conn, err := net.Dial("tcp", ln.Addr().String())
    62  	if err != nil {
    63  		t.Fatal(err)
    64  	}
    65  	file, err := conn.(*net.TCPConn).File()
    66  	if err != nil {
    67  		t.Fatal(err)
    68  	}
    69  	var off int64
    70  	n, err := unix.Sendfile(int(file.Fd()), int(src.Fd()), &off, len(contents))
    71  	if err != nil {
    72  		t.Errorf("Sendfile failed %s\n", err)
    73  	}
    74  	if n != len(contents) {
    75  		t.Errorf("written count wrong: want %d, got %d", len(contents), n)
    76  	}
    77  	// Note: off is updated on some systems and not others. Oh well.
    78  	// Linux: increments off by the amount sent.
    79  	// Darwin: leaves off unchanged.
    80  	// It would be nice to fix Darwin if we can.
    81  	if off != 0 && off != int64(len(contents)) {
    82  		t.Errorf("offset wrong: god %d, want %d or %d", off, 0, len(contents))
    83  	}
    84  	// The cursor position should be unchanged.
    85  	pos, err := src.Seek(0, 1)
    86  	if err != nil {
    87  		t.Errorf("can't get cursor position %s\n", err)
    88  	}
    89  	if pos != 0 {
    90  		t.Errorf("cursor position wrong: got %d, want 0", pos)
    91  	}
    92  
    93  	file.Close() // Note: required to have the close below really send EOF to the server.
    94  	conn.Close()
    95  
    96  	// Wait for server to close.
    97  	<-done
    98  }