// Copyright 2009 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.

//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris

// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris

package unix

import (

	"bytes"

	"sort"

	"sync"

	"syscall"

	"unsafe"

	"golang.org/x/sys/internal/unsafeheader"

)

var (

	Stdin  = 0

	Stdout = 1

	Stderr = 2

)

// Do the interface allocations only once for common

// Errno values.

var (

	errEAGAIN error = syscall.EAGAIN

	errEINVAL error = syscall.EINVAL

	errENOENT error = syscall.ENOENT

)

var (

	signalNameMapOnce sync.Once

	signalNameMap     map[string]syscall.Signal

)

// errnoErr returns common boxed Errno values, to prevent

// allocations at runtime.

func errnoErr(e syscall.Errno) error {

	switch e {

	case 0:

		return nil

	case EAGAIN:

		return errEAGAIN

	case EINVAL:

		return errEINVAL

	case ENOENT:

		return errENOENT

	}

	return e

}

// ErrnoName returns the error name for error number e.

func ErrnoName(e syscall.Errno) string {

	i := sort.Search(len(errorList), func(i int) bool {

		return errorList[i].num >= e

	})

	if i < len(errorList) && errorList[i].num == e {

		return errorList[i].name

	}

	return ""

}

// SignalName returns the signal name for signal number s.

func SignalName(s syscall.Signal) string {

	i := sort.Search(len(signalList), func(i int) bool {

		return signalList[i].num >= s

	})

	if i < len(signalList) && signalList[i].num == s {

		return signalList[i].name

	}

	return ""

}

// SignalNum returns the syscall.Signal for signal named s,

// or 0 if a signal with such name is not found.

// The signal name should start with "SIG".

func SignalNum(s string) syscall.Signal {

	signalNameMapOnce.Do(func() {

		signalNameMap = make(map[string]syscall.Signal, len(signalList))

		for _, signal := range signalList {

			signalNameMap[signal.name] = signal.num

		}

	})

	return signalNameMap[s]

}

// clen returns the index of the first NULL byte in n or len(n) if n contains no NULL byte.

func clen(n []byte) int {

	i := bytes.IndexByte(n, 0)

	if i == -1 {

		i = len(n)

	}

	return i

}

// Mmap manager, for use by operating system-specific implementations.

type mmapper struct {

	sync.Mutex

	active map[*byte][]byte // active mappings; key is last byte in mapping

	mmap   func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, error)

	munmap func(addr uintptr, length uintptr) error

}

func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {

	if length <= 0 {

		return nil, EINVAL

	}

	// Map the requested memory.

	addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)

	if errno != nil {

		return nil, errno

	}

	// Use unsafe to convert addr into a []byte.

	var b []byte

	hdr := (*unsafeheader.Slice)(unsafe.Pointer(&b))

	hdr.Data = unsafe.Pointer(addr)

	hdr.Cap = length

	hdr.Len = length

	// Register mapping in m and return it.

	p := &b[cap(b)-1]

	m.Lock()

	defer m.Unlock()

	m.active[p] = b

	return b, nil

}

func (m *mmapper) Munmap(data []byte) (err error) {

	if len(data) == 0 || len(data) != cap(data) {

		return EINVAL

	}

	// Find the base of the mapping.

	p := &data[cap(data)-1]

	m.Lock()

	defer m.Unlock()

	b := m.active[p]

	if b == nil || &b[0] != &data[0] {

		return EINVAL

	}

	// Unmap the memory and update m.

	if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {

		return errno

	}

	delete(m.active, p)

	return nil

}

func Read(fd int, p []byte) (n int, err error) {

	n, err = read(fd, p)

	if raceenabled {

		if n > 0 {

			raceWriteRange(unsafe.Pointer(&p[0]), n)

		}

		if err == nil {

			raceAcquire(unsafe.Pointer(&ioSync))

		}

	}

	return

}

func Write(fd int, p []byte) (n int, err error) {

	if raceenabled {

		raceReleaseMerge(unsafe.Pointer(&ioSync))

	}

	n, err = write(fd, p)

	if raceenabled && n > 0 {

		raceReadRange(unsafe.Pointer(&p[0]), n)

	}

	return

}

// For testing: clients can set this flag to force

// creation of IPv6 sockets to return EAFNOSUPPORT.

var SocketDisableIPv6 bool

// Sockaddr represents a socket address.

type Sockaddr interface {

	sockaddr() (ptr unsafe.Pointer, len _Socklen, err error) // lowercase; only we can define Sockaddrs

}

// SockaddrInet4 implements the Sockaddr interface for AF_INET type sockets.

type SockaddrInet4 struct {

	Port int

	Addr [4]byte

	raw  RawSockaddrInet4

}

// SockaddrInet6 implements the Sockaddr interface for AF_INET6 type sockets.

type SockaddrInet6 struct {

	Port   int

	ZoneId uint32

	Addr   [16]byte

	raw    RawSockaddrInet6

}

// SockaddrUnix implements the Sockaddr interface for AF_UNIX type sockets.

type SockaddrUnix struct {

	Name string

	raw  RawSockaddrUnix

}

func Bind(fd int, sa Sockaddr) (err error) {

	ptr, n, err := sa.sockaddr()

	if err != nil {

		return err

	}

	return bind(fd, ptr, n)

}

func Connect(fd int, sa Sockaddr) (err error) {

	ptr, n, err := sa.sockaddr()

	if err != nil {

		return err

	}

	return connect(fd, ptr, n)

}

func Getpeername(fd int) (sa Sockaddr, err error) {

	var rsa RawSockaddrAny

	var len _Socklen = SizeofSockaddrAny

	if err = getpeername(fd, &rsa, &len); err != nil {

		return

	}

	return anyToSockaddr(fd, &rsa)

}

func GetsockoptByte(fd, level, opt int) (value byte, err error) {

	var n byte

	vallen := _Socklen(1)

	err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)

	return n, err

}

func GetsockoptInt(fd, level, opt int) (value int, err error) {

	var n int32

	vallen := _Socklen(4)

	err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)

	return int(n), err

}

func GetsockoptInet4Addr(fd, level, opt int) (value [4]byte, err error) {

	vallen := _Socklen(4)

	err = getsockopt(fd, level, opt, unsafe.Pointer(&value[0]), &vallen)

	return value, err

}

func GetsockoptIPMreq(fd, level, opt int) (*IPMreq, error) {

	var value IPMreq

	vallen := _Socklen(SizeofIPMreq)

	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)

	return &value, err

}

func GetsockoptIPv6Mreq(fd, level, opt int) (*IPv6Mreq, error) {

	var value IPv6Mreq

	vallen := _Socklen(SizeofIPv6Mreq)

	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)

	return &value, err

}

func GetsockoptIPv6MTUInfo(fd, level, opt int) (*IPv6MTUInfo, error) {

	var value IPv6MTUInfo

	vallen := _Socklen(SizeofIPv6MTUInfo)

	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)

	return &value, err

}

func GetsockoptICMPv6Filter(fd, level, opt int) (*ICMPv6Filter, error) {

	var value ICMPv6Filter

	vallen := _Socklen(SizeofICMPv6Filter)

	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)

	return &value, err

}

func GetsockoptLinger(fd, level, opt int) (*Linger, error) {

	var linger Linger

	vallen := _Socklen(SizeofLinger)

	err := getsockopt(fd, level, opt, unsafe.Pointer(&linger), &vallen)

	return &linger, err

}

func GetsockoptTimeval(fd, level, opt int) (*Timeval, error) {

	var tv Timeval

	vallen := _Socklen(unsafe.Sizeof(tv))

	err := getsockopt(fd, level, opt, unsafe.Pointer(&tv), &vallen)

	return &tv, err

}

func GetsockoptUint64(fd, level, opt int) (value uint64, err error) {

	var n uint64

	vallen := _Socklen(8)

	err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)

	return n, err

}

func Recvfrom(fd int, p []byte, flags int) (n int, from Sockaddr, err error) {

	var rsa RawSockaddrAny

	var len _Socklen = SizeofSockaddrAny

	if n, err = recvfrom(fd, p, flags, &rsa, &len); err != nil {

		return

	}

	if rsa.Addr.Family != AF_UNSPEC {

		from, err = anyToSockaddr(fd, &rsa)

	}

	return

}