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// 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 (
"os"
"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 := os.CreateTemp("", "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)
}
s := unsafe.Slice((*byte)(unsafe.Pointer(base)), 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)
}
}
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