libgo/go/runtime/memmove_linux_amd64_test.go

   1 // Copyright 2013 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 package runtime_test
   6
   7 import (
   8         "io/ioutil"
   9         "os"
  10         "reflect"
  11         "syscall"
  12         "testing"
  13         "unsafe"
  14 )
  15
  16 // TestMemmoveOverflow maps 3GB of memory and calls memmove on
  17 // the corresponding slice.
  18 func TestMemmoveOverflow(t *testing.T) {
  19         t.Parallel()
  20         // Create a temporary file.
  21         tmp, err := ioutil.TempFile("", "go-memmovetest")
  22         if err != nil {
  23                 t.Fatal(err)
  24         }
  25         _, err = tmp.Write(make([]byte, 65536))
  26         if err != nil {
  27                 t.Fatal(err)
  28         }
  29         defer os.Remove(tmp.Name())
  30         defer tmp.Close()
  31
  32         // Set up mappings.
  33         base, _, errno := syscall.Syscall6(syscall.SYS_MMAP,
  34                 0xa0<<32, 3<<30, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_PRIVATE|syscall.MAP_ANONYMOUS, ^uintptr(0), 0)
  35         if errno != 0 {
  36                 t.Skipf("could not create memory mapping: %s", errno)
  37         }
  38         syscall.Syscall(syscall.SYS_MUNMAP, base, 3<<30, 0)
  39
  40         for off := uintptr(0); off < 3<<30; off += 65536 {
  41                 _, _, errno := syscall.Syscall6(syscall.SYS_MMAP,
  42                         base+off, 65536, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED|syscall.MAP_FIXED, tmp.Fd(), 0)
  43                 if errno != 0 {
  44                         t.Skipf("could not map a page at requested 0x%x: %s", base+off, errno)
  45                 }
  46                 defer syscall.Syscall(syscall.SYS_MUNMAP, base+off, 65536, 0)
  47         }
  48
  49         var s []byte
  50         sp := (*reflect.SliceHeader)(unsafe.Pointer(&s))
  51         sp.Data = base
  52         sp.Len, sp.Cap = 3<<30, 3<<30
  53
  54         n := copy(s[1:], s)
  55         if n != 3<<30-1 {
  56                 t.Fatalf("copied %d bytes, expected %d", n, 3<<30-1)
  57         }
  58         n = copy(s, s[1:])
  59         if n != 3<<30-1 {
  60                 t.Fatalf("copied %d bytes, expected %d", n, 3<<30-1)
  61         }
  62 }