rss-tools @ master

// 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

package unix

import (

	"bytes"

	"sort"

	"sync"

	"syscall"

	"unsafe"

)

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.

	b := unsafe.Slice((*byte)(unsafe.Pointer(addr)), 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 Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {

	return mapper.Mmap(fd, offset, length, prot, flags)

}

func Munmap(b []byte) (err error) {

	return mapper.Munmap(b)

}

func MmapPtr(fd int, offset int64, addr unsafe.Pointer, length uintptr, prot int, flags int) (ret unsafe.Pointer, err error) {

	xaddr, err := mapper.mmap(uintptr(addr), length, prot, flags, fd, offset)

	return unsafe.Pointer(xaddr), err

}

func MunmapPtr(addr unsafe.Pointer, length uintptr) (err error) {

	return mapper.munmap(uintptr(addr), length)

}

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

}

func Pread(fd int, p []byte, offset int64) (n int, err error) {

	n, err = pread(fd, p, offset)

	if raceenabled {

		if n > 0 {

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

		}

		if err == nil {

			raceAcquire(unsafe.Pointer(&ioSync))

		}

	}

	return

}

func Pwrite(fd int, p []byte, offset int64) (n int, err error) {

	if raceenabled {

		raceReleaseMerge(unsafe.Pointer(&ioSync))

	}

	n, err = pwrite(fd, p, offset)

	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

}

// Recvmsg receives a message from a socket using the recvmsg system call. The

// received non-control data will be written to p, and any "out of band"

// control data will be written to oob. The flags are passed to recvmsg.

//

// The results are:

//   - n is the number of non-control data bytes read into p

//   - oobn is the number of control data bytes read into oob; this may be interpreted using [ParseSocketControlMessage]

//   - recvflags is flags returned by recvmsg

//   - from is the address of the sender

//

// If the underlying socket type is not SOCK_DGRAM, a received message

// containing oob data and a single '\0' of non-control data is treated as if

// the message contained only control data, i.e. n will be zero on return.

func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {

	var iov [1]Iovec

	if len(p) > 0 {

		iov[0].Base = &p[0]

		iov[0].SetLen(len(p))

	}

	var rsa RawSockaddrAny

	if n, oobn, recvflags, err = recvmsgRaw(fd, iov[:], oob, flags, &rsa); err != nil {

		return

	}

	// source address is only specified if the socket is unconnected

	if rsa.Addr.Family != AF_UNSPEC {

		from, err = anyToSockaddr(fd, &rsa)

	}

	return

}

// RecvmsgBuffers receives a message from a socket using the recvmsg system

// call. This function is equivalent to Recvmsg, but non-control data read is

// scattered into the buffers slices.

func RecvmsgBuffers(fd int, buffers [][]byte, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {

	iov := make([]Iovec, len(buffers))

	for i := range buffers {

		if len(buffers[i]) > 0 {

			iov[i].Base = &buffers[i][0]

			iov[i].SetLen(len(buffers[i]))

		} else {

			iov[i].Base = (*byte)(unsafe.Pointer(&_zero))

		}

	}

	var rsa RawSockaddrAny

	if n, oobn, recvflags, err = recvmsgRaw(fd, iov, oob, flags, &rsa); err != nil {

		return

	}

	if rsa.Addr.Family != AF_UNSPEC {

		from, err = anyToSockaddr(fd, &rsa)

	}

	return

}

// Sendmsg sends a message on a socket to an address using the sendmsg system

// call. This function is equivalent to SendmsgN, but does not return the

// number of bytes actually sent.

func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {

	_, err = SendmsgN(fd, p, oob, to, flags)

	return

}

// SendmsgN sends a message on a socket to an address using the sendmsg system

// call. p contains the non-control data to send, and oob contains the "out of

// band" control data. The flags are passed to sendmsg. The number of

// non-control bytes actually written to the socket is returned.

//

// Some socket types do not support sending control data without accompanying

// non-control data. If p is empty, and oob contains control data, and the

// underlying socket type is not SOCK_DGRAM, p will be treated as containing a

// single '\0' and the return value will indicate zero bytes sent.

//

// The Go function Recvmsg, if called with an empty p and a non-empty oob,

// will read and ignore this additional '\0'.  If the message is received by

// code that does not use Recvmsg, or that does not use Go at all, that code

// will need to be written to expect and ignore the additional '\0'.

//

// If you need to send non-empty oob with p actually empty, and if the

// underlying socket type supports it, you can do so via a raw system call as

// follows:

//

//	msg := &unix.Msghdr{

//	    Control: &oob[0],

//	}

//	msg.SetControllen(len(oob))

//	n, _, errno := unix.Syscall(unix.SYS_SENDMSG, uintptr(fd), uintptr(unsafe.Pointer(msg)), flags)

func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error) {

	var iov [1]Iovec

	if len(p) > 0 {

		iov[0].Base = &p[0]

		iov[0].SetLen(len(p))

	}

	var ptr unsafe.Pointer

	var salen _Socklen

	if to != nil {

		ptr, salen, err = to.sockaddr()

		if err != nil {

			return 0, err

		}

	}

	return sendmsgN(fd, iov[:], oob, ptr, salen, flags)

}

// SendmsgBuffers sends a message on a socket to an address using the sendmsg

// system call. This function is equivalent to SendmsgN, but the non-control

// data is gathered from buffers.

func SendmsgBuffers(fd int, buffers [][]byte, oob []byte, to Sockaddr, flags int) (n int, err error) {

	iov := make([]Iovec, len(buffers))

	for i := range buffers {

		if len(buffers[i]) > 0 {

			iov[i].Base = &buffers[i][0]

			iov[i].SetLen(len(buffers[i]))

		} else {

			iov[i].Base = (*byte)(unsafe.Pointer(&_zero))

		}

	}

	var ptr unsafe.Pointer

	var salen _Socklen

	if to != nil {

		ptr, salen, err = to.sockaddr()

		if err != nil {

			return 0, err

		}

	}

	return sendmsgN(fd, iov, oob, ptr, salen, flags)

}

func Send(s int, buf []byte, flags int) (err error) {

	return sendto(s, buf, flags, nil, 0)

}

func Sendto(fd int, p []byte, flags int, to Sockaddr) (err error) {

	var ptr unsafe.Pointer

	var salen _Socklen

	if to != nil {

		ptr, salen, err = to.sockaddr()

		if err != nil {

			return err

		}

	}

	return sendto(fd, p, flags, ptr, salen)

}

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

	return setsockopt(fd, level, opt, unsafe.Pointer(&value), 1)

}

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

	var n = int32(value)

	return setsockopt(fd, level, opt, unsafe.Pointer(&n), 4)

}

func SetsockoptInet4Addr(fd, level, opt int, value [4]byte) (err error) {

	return setsockopt(fd, level, opt, unsafe.Pointer(&value[0]), 4)

}

func SetsockoptIPMreq(fd, level, opt int, mreq *IPMreq) (err error) {

	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPMreq)

}

func SetsockoptIPv6Mreq(fd, level, opt int, mreq *IPv6Mreq) (err error) {

	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPv6Mreq)

}

func SetsockoptICMPv6Filter(fd, level, opt int, filter *ICMPv6Filter) error {

	return setsockopt(fd, level, opt, unsafe.Pointer(filter), SizeofICMPv6Filter)

}

func SetsockoptLinger(fd, level, opt int, l *Linger) (err error) {

	return setsockopt(fd, level, opt, unsafe.Pointer(l), SizeofLinger)

}

func SetsockoptString(fd, level, opt int, s string) (err error) {

	var p unsafe.Pointer

	if len(s) > 0 {

		p = unsafe.Pointer(&[]byte(s)[0])

	}

	return setsockopt(fd, level, opt, p, uintptr(len(s)))

}

func SetsockoptTimeval(fd, level, opt int, tv *Timeval) (err error) {

	return setsockopt(fd, level, opt, unsafe.Pointer(tv), unsafe.Sizeof(*tv))

}

func SetsockoptUint64(fd, level, opt int, value uint64) (err error) {

	return setsockopt(fd, level, opt, unsafe.Pointer(&value), 8)

}

func Socket(domain, typ, proto int) (fd int, err error) {

	if domain == AF_INET6 && SocketDisableIPv6 {

		return -1, EAFNOSUPPORT

	}

	fd, err = socket(domain, typ, proto)

	return

}

func Socketpair(domain, typ, proto int) (fd [2]int, err error) {

	var fdx [2]int32

	err = socketpair(domain, typ, proto, &fdx)

	if err == nil {

		fd[0] = int(fdx[0])

		fd[1] = int(fdx[1])

	}

	return

}

var ioSync int64

func CloseOnExec(fd int) { fcntl(fd, F_SETFD, FD_CLOEXEC) }

func SetNonblock(fd int, nonblocking bool) (err error) {

	flag, err := fcntl(fd, F_GETFL, 0)

	if err != nil {

		return err

	}

	if (flag&O_NONBLOCK != 0) == nonblocking {

		return nil

	}

	if nonblocking {

		flag |= O_NONBLOCK

	} else {

		flag &= ^O_NONBLOCK

	}

	_, err = fcntl(fd, F_SETFL, flag)

	return err

}

// Exec calls execve(2), which replaces the calling executable in the process

// tree. argv0 should be the full path to an executable ("/bin/ls") and the

// executable name should also be the first argument in argv (["ls", "-l"]).

// envv are the environment variables that should be passed to the new

// process (["USER=go", "PWD=/tmp"]).

func Exec(argv0 string, argv []string, envv []string) error {

	return syscall.Exec(argv0, argv, envv)

}

// Lutimes sets the access and modification times tv on path. If path refers to

// a symlink, it is not dereferenced and the timestamps are set on the symlink.

// If tv is nil, the access and modification times are set to the current time.

// Otherwise tv must contain exactly 2 elements, with access time as the first

// element and modification time as the second element.

func Lutimes(path string, tv []Timeval) error {

	if tv == nil {

		return UtimesNanoAt(AT_FDCWD, path, nil, AT_SYMLINK_NOFOLLOW)

	}

	if len(tv) != 2 {

		return EINVAL

	}

	ts := []Timespec{

		NsecToTimespec(TimevalToNsec(tv[0])),

		NsecToTimespec(TimevalToNsec(tv[1])),

	}

	return UtimesNanoAt(AT_FDCWD, path, ts, AT_SYMLINK_NOFOLLOW)

}

// emptyIovecs reports whether there are no bytes in the slice of Iovec.

func emptyIovecs(iov []Iovec) bool {

	for i := range iov {

		if iov[i].Len > 0 {

			return false

		}

	}

	return true

}

// Setrlimit sets a resource limit.

func Setrlimit(resource int, rlim *Rlimit) error {

	// Just call the syscall version, because as of Go 1.21

	// it will affect starting a new process.

	return syscall.Setrlimit(resource, (*syscall.Rlimit)(rlim))

}