// Copyright 2009,2010 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.

// Darwin system calls.

// This file is compiled as ordinary Go code,

// but it is also input to mksyscall,

// which parses the //sys lines and generates system call stubs.

// Note that sometimes we use a lowercase //sys name and wrap

// it in our own nicer implementation, either here or in

// syscall_bsd.go or syscall_unix.go.

package unix

import (

	"fmt"

	"runtime"

	"syscall"

	"unsafe"

)

// SockaddrDatalink implements the Sockaddr interface for AF_LINK type sockets.

type SockaddrDatalink struct {

	Len    uint8

	Family uint8

	Index  uint16

	Type   uint8

	Nlen   uint8

	Alen   uint8

	Slen   uint8

	Data   [12]int8

	raw    RawSockaddrDatalink

}

// SockaddrCtl implements the Sockaddr interface for AF_SYSTEM type sockets.

type SockaddrCtl struct {

	ID   uint32

	Unit uint32

	raw  RawSockaddrCtl

}

func (sa *SockaddrCtl) sockaddr() (unsafe.Pointer, _Socklen, error) {

	sa.raw.Sc_len = SizeofSockaddrCtl

	sa.raw.Sc_family = AF_SYSTEM

	sa.raw.Ss_sysaddr = AF_SYS_CONTROL

	sa.raw.Sc_id = sa.ID

	sa.raw.Sc_unit = sa.Unit

	return unsafe.Pointer(&sa.raw), SizeofSockaddrCtl, nil

}

// SockaddrVM implements the Sockaddr interface for AF_VSOCK type sockets.

// SockaddrVM provides access to Darwin VM sockets: a mechanism that enables

// bidirectional communication between a hypervisor and its guest virtual

// machines.

type SockaddrVM struct {

	// CID and Port specify a context ID and port address for a VM socket.

	// Guests have a unique CID, and hosts may have a well-known CID of:

	//  - VMADDR_CID_HYPERVISOR: refers to the hypervisor process.

	//  - VMADDR_CID_LOCAL: refers to local communication (loopback).

	//  - VMADDR_CID_HOST: refers to other processes on the host.

	CID  uint32

	Port uint32

	raw  RawSockaddrVM

}

func (sa *SockaddrVM) sockaddr() (unsafe.Pointer, _Socklen, error) {

	sa.raw.Len = SizeofSockaddrVM

	sa.raw.Family = AF_VSOCK

	sa.raw.Port = sa.Port

	sa.raw.Cid = sa.CID

	return unsafe.Pointer(&sa.raw), SizeofSockaddrVM, nil

}

func anyToSockaddrGOOS(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {

	switch rsa.Addr.Family {

	case AF_SYSTEM:

		pp := (*RawSockaddrCtl)(unsafe.Pointer(rsa))

		if pp.Ss_sysaddr == AF_SYS_CONTROL {

			sa := new(SockaddrCtl)

			sa.ID = pp.Sc_id

			sa.Unit = pp.Sc_unit

			return sa, nil

		}

	case AF_VSOCK:

		pp := (*RawSockaddrVM)(unsafe.Pointer(rsa))

		sa := &SockaddrVM{

			CID:  pp.Cid,

			Port: pp.Port,

		}

		return sa, nil

	}

	return nil, EAFNOSUPPORT

}

// Some external packages rely on SYS___SYSCTL being defined to implement their

// own sysctl wrappers. Provide it here, even though direct syscalls are no

// longer supported on darwin.

const SYS___SYSCTL = SYS_SYSCTL

// Translate "kern.hostname" to []_C_int{0,1,2,3}.

func nametomib(name string) (mib []_C_int, err error) {

	const siz = unsafe.Sizeof(mib[0])

	// NOTE(rsc): It seems strange to set the buffer to have

	// size CTL_MAXNAME+2 but use only CTL_MAXNAME

	// as the size. I don't know why the +2 is here, but the

	// kernel uses +2 for its own implementation of this function.

	// I am scared that if we don't include the +2 here, the kernel

	// will silently write 2 words farther than we specify

	// and we'll get memory corruption.

	var buf [CTL_MAXNAME + 2]_C_int

	n := uintptr(CTL_MAXNAME) * siz

	p := (*byte)(unsafe.Pointer(&buf[0]))

	bytes, err := ByteSliceFromString(name)

	if err != nil {

		return nil, err

	}

	// Magic sysctl: "setting" 0.3 to a string name

	// lets you read back the array of integers form.

	if err = sysctl([]_C_int{0, 3}, p, &n, &bytes[0], uintptr(len(name))); err != nil {

		return nil, err

	}

	return buf[0 : n/siz], nil

}

func direntIno(buf []byte) (uint64, bool) {

	return readInt(buf, unsafe.Offsetof(Dirent{}.Ino), unsafe.Sizeof(Dirent{}.Ino))

}

func direntReclen(buf []byte) (uint64, bool) {

	return readInt(buf, unsafe.Offsetof(Dirent{}.Reclen), unsafe.Sizeof(Dirent{}.Reclen))

}

func direntNamlen(buf []byte) (uint64, bool) {

	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))

}

func PtraceAttach(pid int) (err error) { return ptrace(PT_ATTACH, pid, 0, 0) }

func PtraceDetach(pid int) (err error) { return ptrace(PT_DETACH, pid, 0, 0) }

//sysnb	pipe(p *[2]int32) (err error)

func Pipe(p []int) (err error) {

	if len(p) != 2 {

		return EINVAL

	}

	var x [2]int32

	err = pipe(&x)

	if err == nil {

		p[0] = int(x[0])

		p[1] = int(x[1])

	}

	return

}

func Getfsstat(buf []Statfs_t, flags int) (n int, err error) {

	var _p0 unsafe.Pointer

	var bufsize uintptr

	if len(buf) > 0 {

		_p0 = unsafe.Pointer(&buf[0])

		bufsize = unsafe.Sizeof(Statfs_t{}) * uintptr(len(buf))

	}

	return getfsstat(_p0, bufsize, flags)

}

func xattrPointer(dest []byte) *byte {

	// It's only when dest is set to NULL that the OS X implementations of

	// getxattr() and listxattr() return the current sizes of the named attributes.

	// An empty byte array is not sufficient. To maintain the same behaviour as the

	// linux implementation, we wrap around the system calls and pass in NULL when

	// dest is empty.

	var destp *byte

	if len(dest) > 0 {

		destp = &dest[0]

	}

	return destp

}

//sys	getxattr(path string, attr string, dest *byte, size int, position uint32, options int) (sz int, err error)

func Getxattr(path string, attr string, dest []byte) (sz int, err error) {

	return getxattr(path, attr, xattrPointer(dest), len(dest), 0, 0)

}

func Lgetxattr(link string, attr string, dest []byte) (sz int, err error) {

	return getxattr(link, attr, xattrPointer(dest), len(dest), 0, XATTR_NOFOLLOW)

}

//sys	fgetxattr(fd int, attr string, dest *byte, size int, position uint32, options int) (sz int, err error)

func Fgetxattr(fd int, attr string, dest []byte) (sz int, err error) {

	return fgetxattr(fd, attr, xattrPointer(dest), len(dest), 0, 0)

}

//sys	setxattr(path string, attr string, data *byte, size int, position uint32, options int) (err error)

func Setxattr(path string, attr string, data []byte, flags int) (err error) {

	// The parameters for the OS X implementation vary slightly compared to the

	// linux system call, specifically the position parameter:

	//

	//  linux:

	//      int setxattr(

	//          const char *path,

	//          const char *name,

	//          const void *value,

	//          size_t size,

	//          int flags

	//      );

	//

	//  darwin:

	//      int setxattr(

	//          const char *path,

	//          const char *name,

	//          void *value,

	//          size_t size,

	//          u_int32_t position,

	//          int options

	//      );

	//

	// position specifies the offset within the extended attribute. In the

	// current implementation, only the resource fork extended attribute makes

	// use of this argument. For all others, position is reserved. We simply

	// default to setting it to zero.

	return setxattr(path, attr, xattrPointer(data), len(data), 0, flags)

}

func Lsetxattr(link string, attr string, data []byte, flags int) (err error) {

	return setxattr(link, attr, xattrPointer(data), len(data), 0, flags|XATTR_NOFOLLOW)

}

//sys	fsetxattr(fd int, attr string, data *byte, size int, position uint32, options int) (err error)

func Fsetxattr(fd int, attr string, data []byte, flags int) (err error) {

	return fsetxattr(fd, attr, xattrPointer(data), len(data), 0, 0)

}

//sys	removexattr(path string, attr string, options int) (err error)

func Removexattr(path string, attr string) (err error) {

	// We wrap around and explicitly zero out the options provided to the OS X

	// implementation of removexattr, we do so for interoperability with the

	// linux variant.

	return removexattr(path, attr, 0)

}

func Lremovexattr(link string, attr string) (err error) {

	return removexattr(link, attr, XATTR_NOFOLLOW)

}

//sys	fremovexattr(fd int, attr string, options int) (err error)

func Fremovexattr(fd int, attr string) (err error) {

	return fremovexattr(fd, attr, 0)

}

//sys	listxattr(path string, dest *byte, size int, options int) (sz int, err error)

func Listxattr(path string, dest []byte) (sz int, err error) {

	return listxattr(path, xattrPointer(dest), len(dest), 0)

}

func Llistxattr(link string, dest []byte) (sz int, err error) {

	return listxattr(link, xattrPointer(dest), len(dest), XATTR_NOFOLLOW)

}

//sys	flistxattr(fd int, dest *byte, size int, options int) (sz int, err error)

func Flistxattr(fd int, dest []byte) (sz int, err error) {

	return flistxattr(fd, xattrPointer(dest), len(dest), 0)

}

//sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)

/*

 * Wrapped

 */

//sys	fcntl(fd int, cmd int, arg int) (val int, err error)

//sys	kill(pid int, signum int, posix int) (err error)

func Kill(pid int, signum syscall.Signal) (err error) { return kill(pid, int(signum), 1) }

//sys	ioctl(fd int, req uint, arg uintptr) (err error)

func IoctlCtlInfo(fd int, ctlInfo *CtlInfo) error {

	err := ioctl(fd, CTLIOCGINFO, uintptr(unsafe.Pointer(ctlInfo)))

	runtime.KeepAlive(ctlInfo)

	return err

}

// IfreqMTU is struct ifreq used to get or set a network device's MTU.

type IfreqMTU struct {

	Name [IFNAMSIZ]byte

	MTU  int32

}

// IoctlGetIfreqMTU performs the SIOCGIFMTU ioctl operation on fd to get the MTU

// of the network device specified by ifname.

func IoctlGetIfreqMTU(fd int, ifname string) (*IfreqMTU, error) {

	var ifreq IfreqMTU

	copy(ifreq.Name[:], ifname)

	err := ioctl(fd, SIOCGIFMTU, uintptr(unsafe.Pointer(&ifreq)))

	return &ifreq, err

}

// IoctlSetIfreqMTU performs the SIOCSIFMTU ioctl operation on fd to set the MTU