// 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 syscall

import (
	errorspkg "errors"
	"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
}

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 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))
}

//sys   ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
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
	attrCmnModtime  = 0x00000400
	attrCmnAcctime  = 0x00001000
	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, errorspkg.New("attrBuf too small")
	}
	attrList.bitmapCount = attrBitMapCount

	var _p0 *byte
	_p0, err = BytePtrFromString(path)
	if err != nil {
		return nil, err
	}

	_, _, e1 := Syscall6(
		SYS_GETATTRLIST,
		uintptr(unsafe.Pointer(_p0)),
		uintptr(unsafe.Pointer(&attrList)),
		uintptr(unsafe.Pointer(&attrBuf[0])),
		uintptr(len(attrBuf)),
		uintptr(options),
		0,
	)
	if e1 != 0 {
		return nil, e1
	}
	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, errorspkg.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, errorspkg.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))
	}
	r0, _, e1 := Syscall(SYS_GETFSSTAT64, uintptr(_p0), bufsize, uintptr(flags))
	n = int(r0)
	if e1 != 0 {
		err = e1
	}
	return
}

func setattrlistTimes(path string, times []Timespec) error {
	_p0, err := BytePtrFromString(path)
	if err != nil {
		return err
	}

	var attrList attrList
	attrList.bitmapCount = attrBitMapCount
	attrList.CommonAttr = attrCmnModtime | attrCmnAcctime

	// order is mtime, atime: the opposite of Chtimes
	attributes := [2]Timespec{times[1], times[0]}
	const options = 0
	_, _, e1 := Syscall6(
		SYS_SETATTRLIST,
		uintptr(unsafe.Pointer(_p0)),
		uintptr(unsafe.Pointer(&attrList)),
		uintptr(unsafe.Pointer(&attributes)),
		uintptr(unsafe.Sizeof(attributes)),
		uintptr(options),
		0,
	)
	if e1 != 0 {
		return e1
	}
	return nil
}

func utimensat(dirfd int, path string, times *[2]Timespec, flag 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 Signal) (err error) { return kill(pid, int(signum), 1) }

/*
 * 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)
//sys	Close(fd int) (err error)
//sys	Dup(fd int) (nfd int, err error)
//sys	Dup2(from int, to int) (err error)
//sys	Exchangedata(path1 string, path2 string, options int) (err error)
//sys	Fchdir(fd int) (err error)
//sys	Fchflags(fd int, flags int) (err error)
//sys	Fchmod(fd int, mode uint32) (err error)
//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Flock(fd int, how int) (err error)
//sys	Fpathconf(fd int, name int) (val int, err error)
//sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
//sys	Fstatfs(fd int, stat *Statfs_t) (err error) = SYS_FSTATFS64
//sys	Fsync(fd int) (err error)
//sys	Ftruncate(fd int, length int64) (err error)
//sys	Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) = SYS_GETDIRENTRIES64
//sys	Getdtablesize() (size int)
//sysnb	Getegid() (egid int)
//sysnb	Geteuid() (uid int)
//sysnb	Getgid() (gid int)
//sysnb	Getpgid(pid int) (pgid int, err error)
//sysnb	Getpgrp() (pgrp int)
//sysnb	Getpid() (pid int)
//sysnb	Getppid() (ppid int)
//sys	Getpriority(which int, who int) (prio int, err error)
//sysnb	Getrlimit(which int, lim *Rlimit) (err error)
//sysnb	Getrusage(who int, rusage *Rusage) (err error)
//sysnb	Getsid(pid int) (sid int, err error)
//sysnb	Getuid() (uid int)
//sysnb	Issetugid() (tainted bool)
//sys	Kqueue() (fd int, err error)
//sys	Lchown(path string, uid int, gid int) (err error)
//sys	Link(path string, link string) (err error)
//sys	Listen(s int, backlog int) (err error)
//sys	Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
//sys	Mkdir(path string, mode uint32) (err error)
//sys	Mkfifo(path string, mode uint32) (err error)
//sys	Mknod(path string, mode uint32, dev int) (err error)
//sys	Mlock(b []byte) (err error)
//sys	Mlockall(flags int) (err error)
//sys	Mprotect(b []byte, prot int) (err error)
//sys	Munlock(b []byte) (err error)
//sys	Munlockall() (err error)
//sys	Open(path string, mode int, perm uint32) (fd int, err error)
//sys	Pathconf(path string, name int) (val int, err error)
//sys	Pread(fd int, p []byte, offset int64) (n int, err error)
//sys	Pwrite(fd int, p []byte, offset int64) (n int, err error)
//sys	read(fd int, p []byte) (n int, err error)
//sys	Readlink(path string, buf []byte) (n int, err error)
//sys	Rename(from string, to string) (err error)
//sys	Revoke(path string) (err error)
//sys	Rmdir(path string) (err error)
//sys	Seek(fd int, offset int64, whence int) (newoffset int64, err error) = SYS_LSEEK
//sys	Select(n int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (err error)
//sys	Setegid(egid int) (err error)
//sysnb	Seteuid(euid int) (err error)
//sysnb	Setgid(gid int) (err error)
//sys	Setlogin(name string) (err error)
//sysnb	Setpgid(pid int, pgid int) (err error)
//sys	Setpriority(which int, who int, prio int) (err error)
//sys	Setprivexec(flag int) (err error)
//sysnb	Setregid(rgid int, egid int) (err error)
//sysnb	Setreuid(ruid int, euid int) (err error)
//sysnb	Setrlimit(which int, lim *Rlimit) (err error)
//sysnb	Setsid() (pid int, err error)
//sysnb	Settimeofday(tp *Timeval) (err error)
//sysnb	Setuid(uid int) (err error)
//sys	Stat(path string, stat *Stat_t) (err error) = SYS_STAT64
//sys	Statfs(path string, stat *Statfs_t) (err error) = SYS_STATFS64
//sys	Symlink(path string, link string) (err error)
//sys	Sync() (err error)
//sys	Truncate(path string, length int64) (err error)
//sys	Umask(newmask int) (oldmask int)
//sys	Undelete(path string) (err error)
//sys	Unlink(path string) (err error)
//sys	Unmount(path string, flags int) (err error)
//sys	write(fd int, p []byte) (n int, err error)
//sys   mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error)
//sys   munmap(addr uintptr, length uintptr) (err error)
//sys	readlen(fd int, buf *byte, nbuf int) (n int, err error) = SYS_READ
//sys	writelen(fd int, buf *byte, nbuf int) (n int, err error) = SYS_WRITE