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))

// license that can be found in the LICENSE file.

package cov

import (
	"cmd/internal/bio"
	"io"
	"os"
)

// This file contains the helper "MReader", a wrapper around bio plus
// an "mmap'd read-only" view of the file obtained from bio.SliceRO().
// MReader is designed to implement the io.ReaderSeeker interface.
// Since bio.SliceOS() is not guaranteed to succeed, MReader falls back

// mmap calls the mmap system call. It is implemented in assembly.
// We only pass the lower 32 bits of file offset to the
// assembly routine; the higher bits (if required), should be provided
// by the assembly routine as 0.
// The err result is an OS error code such as ENOMEM.
func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (p unsafe.Pointer, err int)

	_, err = fcntl(int(out.f.Fd()), syscall.F_PREALLOCATE, int(uintptr(unsafe.Pointer(store))))
	return err
}

func (out *OutBuf) purgeSignatureCache() {
	// Apparently, the Darwin kernel may cache the code signature at mmap.
	// When we mmap the output buffer, it doesn't have a code signature
	// (as we haven't generated one). Invalidate the kernel cache now that
	// we have generated the signature. See issue #42684.
	msync(out.buf, syscall.MS_INVALIDATE)

	mremap func(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (xaddr uintptr, err error)
}

var mapper = &mremapMmapper{
	mmapper: mmapper{
		active: make(map[*byte][]byte),
		mmap:   mmap,
		munmap: munmap,
	},
	mremap: mremap,
}

func (m *mremapMmapper) Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package counter

import (
	"bytes"
	"fmt"
	"strings"
	"unsafe"

	"golang.org/x/telemetry/internal/mmap"
)

type File struct {
	Meta  map[string]string
	Count map[string]uint64
}

func Parse(filename string, data []byte) (*File, error) {
	if !bytes.HasPrefix(data, []byte(hdrPrefix)) || len(data) < pageSize {

	case *matcher.Matcher_MatcherTree_:
		var mmap *matcher.Matcher_MatcherTree_MatchMap
		switch t := m.MatcherTree.TreeType.(type) {
		case *matcher.Matcher_MatcherTree_PrefixMatchMap:
			mmap = t.PrefixMatchMap
		case *matcher.Matcher_MatcherTree_ExactMatchMap:
			mmap = t.ExactMatchMap
		default:
			return Mapper{}, false
		}
		return Mapper{Matcher: mmatcher, Map: mmap.Map}, true
	}
	return Mapper{}, false

void
x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
{
	uintptr *pbounds;

	/* The memory sanitizer distributed with versions of clang
	   before 3.8 has a bug: if you call mmap before malloc, mmap
	   may return an address that is later overwritten by the msan
	   library.  Avoid this problem by forcing a call to malloc
	   here, before we ever call malloc.

#endif

extern void SigStackCallback();

static void* WithSigStack(void* arg __attribute__((unused))) {
	// Set up an alternate system stack.
	void* base = mmap(0, CSIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
	if (base == MAP_FAILED) {
		perror("mmap failed");
		abort();
	}
	stack_t st = {}, ost = {};
	st.ss_sp = (char*)base;
	st.ss_flags = 0;
	st.ss_size = CSIGSTKSZ;
	if (sigaltstack(&st, &ost) < 0) {

}

void
x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
{
	uintptr *pbounds;

	/* The memory sanitizer distributed with versions of clang
	   before 3.8 has a bug: if you call mmap before malloc, mmap
	   may return an address that is later overwritten by the msan
	   library.  Avoid this problem by forcing a call to malloc
	   here, before we ever call malloc.