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