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