...
Run Format

Source file src/runtime/memmove_linux_amd64_test.go

Documentation: runtime

  // Copyright 2013 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 runtime_test
  
  import (
  	"io/ioutil"
  	"os"
  	"reflect"
  	"syscall"
  	"testing"
  	"unsafe"
  )
  
  // TestMemmoveOverflow maps 3GB of memory and calls memmove on
  // the corresponding slice.
  func TestMemmoveOverflow(t *testing.T) {
  	t.Parallel()
  	// Create a temporary file.
  	tmp, err := ioutil.TempFile("", "go-memmovetest")
  	if err != nil {
  		t.Fatal(err)
  	}
  	_, err = tmp.Write(make([]byte, 65536))
  	if err != nil {
  		t.Fatal(err)
  	}
  	defer os.Remove(tmp.Name())
  	defer tmp.Close()
  
  	// Set up mappings.
  	base, _, errno := syscall.Syscall6(syscall.SYS_MMAP,
  		0xa0<<32, 3<<30, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_PRIVATE|syscall.MAP_ANONYMOUS, ^uintptr(0), 0)
  	if errno != 0 {
  		t.Skipf("could not create memory mapping: %s", errno)
  	}
  	syscall.Syscall(syscall.SYS_MUNMAP, base, 3<<30, 0)
  
  	for off := uintptr(0); off < 3<<30; off += 65536 {
  		_, _, errno := syscall.Syscall6(syscall.SYS_MMAP,
  			base+off, 65536, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED|syscall.MAP_FIXED, tmp.Fd(), 0)
  		if errno != 0 {
  			t.Skipf("could not map a page at requested 0x%x: %s", base+off, errno)
  		}
  		defer syscall.Syscall(syscall.SYS_MUNMAP, base+off, 65536, 0)
  	}
  
  	var s []byte
  	sp := (*reflect.SliceHeader)(unsafe.Pointer(&s))
  	sp.Data = base
  	sp.Len, sp.Cap = 3<<30, 3<<30
  
  	n := copy(s[1:], s)
  	if n != 3<<30-1 {
  		t.Fatalf("copied %d bytes, expected %d", n, 3<<30-1)
  	}
  	n = copy(s, s[1:])
  	if n != 3<<30-1 {
  		t.Fatalf("copied %d bytes, expected %d", n, 3<<30-1)
  	}
  }
  

View as plain text