mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-13 03:29:50 +00:00
48 lines
1.3 KiB
Go
48 lines
1.3 KiB
Go
// 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.
|
|
//
|
|
// +build linux
|
|
|
|
package bytes_test
|
|
|
|
import (
|
|
. "bytes"
|
|
"syscall"
|
|
"testing"
|
|
"unsafe"
|
|
)
|
|
|
|
// This file tests the situation where memeq is checking
|
|
// data very near to a page boundary. We want to make sure
|
|
// equal does not read across the boundary and cause a page
|
|
// fault where it shouldn't.
|
|
|
|
// This test runs only on linux. The code being tested is
|
|
// not OS-specific, so it does not need to be tested on all
|
|
// operating systems.
|
|
|
|
func TestEqualNearPageBoundary(t *testing.T) {
|
|
pagesize := syscall.Getpagesize()
|
|
b := make([]byte, 4*pagesize)
|
|
i := pagesize
|
|
for ; uintptr(unsafe.Pointer(&b[i]))%uintptr(pagesize) != 0; i++ {
|
|
}
|
|
syscall.Mprotect(b[i-pagesize:i], 0)
|
|
syscall.Mprotect(b[i+pagesize:i+2*pagesize], 0)
|
|
defer syscall.Mprotect(b[i-pagesize:i], syscall.PROT_READ|syscall.PROT_WRITE)
|
|
defer syscall.Mprotect(b[i+pagesize:i+2*pagesize], syscall.PROT_READ|syscall.PROT_WRITE)
|
|
|
|
// both of these should fault
|
|
//pagesize += int(b[i-1])
|
|
//pagesize += int(b[i+pagesize])
|
|
|
|
for j := 0; j < pagesize; j++ {
|
|
b[i+j] = 'A'
|
|
}
|
|
for j := 0; j <= pagesize; j++ {
|
|
Equal(b[i:i+j], b[i+pagesize-j:i+pagesize])
|
|
Equal(b[i+pagesize-j:i+pagesize], b[i:i+j])
|
|
}
|
|
}
|