package syscall_test

import (
	"syscall"
	"testing"
)

func TestMmap(t *testing.T) {
	b, err := syscall.Mmap(-1, 0, syscall.Getpagesize(), syscall.PROT_NONE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
	if err != nil {
		t.Fatalf("Mmap: %v", err)
	}
	if err := syscall.Munmap(b); err != nil {
		t.Fatalf("Munmap: %v", err)
	}

package ld

import (
	"internal/unsafeheader"
	"syscall"
	"unsafe"
)

// Mmap maps the output file with the given size. It unmaps the old mapping
// if it is already mapped. It also flushes any in-heap data to the new
// mapping.
func (out *OutBuf) Mmap(filesize uint64) error {
	oldlen := len(out.buf)
	if oldlen != 0 {
		out.munmap()
	}

	err := out.f.Truncate(int64(filesize))
	if err != nil {

// munmap calls the munmap system call. It is implemented in assembly.
func munmap(addr unsafe.Pointer, n uintptr)

func nanotime1() int64

//go:noescape
func sigaltstack(new, old *stackt)

func fcntl(fd, cmd, arg int32) (ret int32, errno int32)

func walltime() (sec int64, nsec int32)

	// doesn't fault. See issue 60825.

	// Mmap two pages of memory, and make the second page inaccessible,
	// so we have an address at the end of a page.
	pagesize := syscall.Getpagesize()
	b, err := syscall.Mmap(0, 0, 2*pagesize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
	if err != nil {
		t.Fatalf("mmap failed %s", err)
	}
	defer syscall.Munmap(b)
	err = syscall.Mprotect(b[pagesize:], syscall.PROT_NONE)

func TestNonGoMemory(t *testing.T) {
	data, err := syscall.Mmap(-1, 0, 4096, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
	if err != nil {
		t.Fatalf("failed to mmap memory: %v", err)
	}
	defer syscall.Munmap(data)
	p := (*uint32)(unsafe.Pointer(&data[0]))
	atomic.AddUint32(p, 1)
	(*p)++
	if *p != 2 {

//go:build !unix && !windows

package ld

// Mmap allocates an in-heap output buffer with the given size. It copies
// any old data (if any) to the new buffer.
func (out *OutBuf) Mmap(filesize uint64) error {
	// We need space to put all the symbols before we apply relocations.
	oldheap := out.heap
	if filesize < uint64(len(oldheap)) {
		panic("mmap size too small")
	}
	out.heap = make([]byte, filesize)

		t.Skip("netbsd-arm doesn't provide fault address (golang.org/issue/45026)")
	}
	m, err := syscall.Mmap(-1, 0, 0x1000, syscall.PROT_READ /* Note: no PROT_WRITE */, syscall.MAP_SHARED|syscall.MAP_ANON)
	if err != nil {
		t.Fatalf("can't map anonymous memory: %s", err)
	}
	defer syscall.Munmap(m)
	old := debug.SetPanicOnFault(true)
	defer debug.SetPanicOnFault(old)
	const lowBits = 0x3e7
	defer func() {

	if fd < 0 {
		atomic.Casuintptr(&hpetDevMap[idx], 0, ^uintptr(0))
		return
	}

	addr, mmapErr := mmap(nil, physPageSize, _PROT_READ, _MAP_SHARED, fd, 0)
	closefd(fd)
	newP := uintptr(addr)
	if mmapErr != 0 {
		newP = ^uintptr(0)
	}
	if !atomic.Casuintptr(&hpetDevMap[idx], 0, newP) && mmapErr == 0 {
		munmap(addr, physPageSize)
	}
}

//go:nosplit
func (th *vdsoTimehands) getTimecounter() (uint32, bool) {

// which prevents us from allocating more stack.
//
//go:nosplit
func sysFreeOS(v unsafe.Pointer, n uintptr) {
	munmap(v, n)
}

func sysFaultOS(v unsafe.Pointer, n uintptr) {
	mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0)
}

func sysReserveOS(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0)
	if err != 0 {
		return nil
	}
	return p
}

		}
		if err != nil {
			t.Fatalf("fallocate failed: %v", err)
		}
		break
	}

	// Mmap 1 MiB initially, and grow to 2 and 3 MiB.
	// Check if the file size and disk usage is expected.
	for _, sz := range []int64{1 << 20, 2 << 20, 3 << 20} {
		err = out.Mmap(uint64(sz))
		if err != nil {
			t.Fatalf("Mmap failed: %v", err)
		}
		stat, err := os.Stat(filename)
		if err != nil {
			t.Fatalf("Stat failed: %v", err)