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 } 63
