// 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 (

	"errors"

	"syscall"

	"unsafe"

)

const ImplementsGetwd = true

func Getwd() (string, error) {

	buf := make([]byte, 2048)

	attrs, err := getAttrList(".", attrList{CommonAttr: attrCmnFullpath}, buf, 0)

	if err == nil && len(attrs) == 1 && len(attrs[0]) >= 2 {

		wd := string(attrs[0])

		// Sanity check that it's an absolute path and ends

		// in a null byte, which we then strip.

		if wd[0] == '/' && wd[len(wd)-1] == 0 {

			return wd[:len(wd)-1], nil

		}

	}

	// If pkg/os/getwd.go gets ENOTSUP, it will fall back to the

	// slow algorithm.

	return "", ENOTSUP

}

// 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

}

// 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 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) }

const (

	attrBitMapCount = 5

	attrCmnFullpath = 0x08000000

)

type attrList struct {

	bitmapCount uint16

	_           uint16

	CommonAttr  uint32

	VolAttr     uint32

	DirAttr     uint32

	FileAttr    uint32

	Forkattr    uint32

}

func getAttrList(path string, attrList attrList, attrBuf []byte, options uint) (attrs [][]byte, err error) {

	if len(attrBuf) < 4 {

		return nil, errors.New("attrBuf too small")

	}

	attrList.bitmapCount = attrBitMapCount

	var _p0 *byte

	_p0, err = BytePtrFromString(path)

	if err != nil {

		return nil, err

	}

	}

	size := *(*uint32)(unsafe.Pointer(&attrBuf[0]))

	// dat is the section of attrBuf that contains valid data,

	// without the 4 byte length header. All attribute offsets

	// are relative to dat.

	dat := attrBuf

	if int(size) < len(attrBuf) {

		dat = dat[:size]

	}

	dat = dat[4:] // remove length prefix

	for i := uint32(0); int(i) < len(dat); {

		header := dat[i:]

		if len(header) < 8 {

			return attrs, errors.New("truncated attribute header")

		}

		datOff := *(*int32)(unsafe.Pointer(&header[0]))

		attrLen := *(*uint32)(unsafe.Pointer(&header[4]))

		if datOff < 0 || uint32(datOff)+attrLen > uint32(len(dat)) {

			return attrs, errors.New("truncated results; attrBuf too small")

		}

		end := uint32(datOff) + attrLen

		attrs = append(attrs, dat[datOff:end])

		i = end

		if r := i % 4; r != 0 {

			i += (4 - r)

		}

	}

	return

}

//sysnb pipe() (r int, w int, err error)

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

	if len(p) != 2 {

		return EINVAL

	}

	p[0], p[1], err = pipe()

	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))

	}

}

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)

}

func setattrlistTimes(path string, times []Timespec, flags int) error {

	_p0, err := BytePtrFromString(path)

	if err != nil {

		return err

	}

	var attrList attrList

	attrList.bitmapCount = ATTR_BIT_MAP_COUNT

	attrList.CommonAttr = ATTR_CMN_MODTIME | ATTR_CMN_ACCTIME

	// order is mtime, atime: the opposite of Chtimes

	attributes := [2]Timespec{times[1], times[0]}

	options := 0

	if flags&AT_SYMLINK_NOFOLLOW != 0 {

		options |= FSOPT_NOFOLLOW

	}

}

func utimensat(dirfd int, path string, times *[2]Timespec, flags int) error {

	// Darwin doesn't support SYS_UTIMENSAT

	return ENOSYS

}

/*

 * Wrapped

 */

//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 Uname(uname *Utsname) error {

	mib := []_C_int{CTL_KERN, KERN_OSTYPE}

	n := unsafe.Sizeof(uname.Sysname)

	if err := sysctl(mib, &uname.Sysname[0], &n, nil, 0); err != nil {

		return err

	}

	mib = []_C_int{CTL_KERN, KERN_HOSTNAME}

	n = unsafe.Sizeof(uname.Nodename)

	if err := sysctl(mib, &uname.Nodename[0], &n, nil, 0); err != nil {

		return err

	}

	mib = []_C_int{CTL_KERN, KERN_OSRELEASE}

	n = unsafe.Sizeof(uname.Release)

	if err := sysctl(mib, &uname.Release[0], &n, nil, 0); err != nil {

		return err

	}

	mib = []_C_int{CTL_KERN, KERN_VERSION}

	n = unsafe.Sizeof(uname.Version)

	if err := sysctl(mib, &uname.Version[0], &n, nil, 0); err != nil {

		return err

	}

	// The version might have newlines or tabs in it, convert them to

	// spaces.

	for i, b := range uname.Version {

		if b == '\n' || b == '\t' {

			if i == len(uname.Version)-1 {

				uname.Version[i] = 0

			} else {

				uname.Version[i] = ' '

			}

		}

	}

	mib = []_C_int{CTL_HW, HW_MACHINE}

	n = unsafe.Sizeof(uname.Machine)

	if err := sysctl(mib, &uname.Machine[0], &n, nil, 0); err != nil {

		return err

	}

	return nil

}

/*

 * Exposed directly

 */

//sys	Access(path string, mode uint32) (err error)

//sys	Adjtime(delta *Timeval, olddelta *Timeval) (err error)

//sys	Chdir(path string) (err error)

//sys	Chflags(path string, flags int) (err error)

//sys	Chmod(path string, mode uint32) (err error)

//sys	Chown(path string, uid int, gid int) (err error)

//sys	Chroot(path string) (err error)