// 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.

// DragonFly BSD 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 (
	"sync"
	"unsafe"
)

// See version list in https://github.com/DragonFlyBSD/DragonFlyBSD/blob/master/sys/sys/param.h
var (
	osreldateOnce sync.Once
	osreldate     uint32
)

// First __DragonFly_version after September 2019 ABI changes
// http://lists.dragonflybsd.org/pipermail/users/2019-September/358280.html
const _dragonflyABIChangeVersion = 500705

func supportsABI(ver uint32) bool {
	osreldateOnce.Do(func() { osreldate, _ = SysctlUint32("kern.osreldate") })
	return osreldate >= ver
}

type SockaddrDatalink struct {
	Len    uint8
	Family uint8
	Index  uint16
	Type   uint8
	Nlen   uint8
	Alen   uint8
	Slen   uint8
	Data   [12]int8
	Rcf    uint16
	Route  [16]uint16
	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{}.Fileno), unsafe.Sizeof(Dirent{}.Fileno))
}

func direntReclen(buf []byte) (uint64, bool) {
	namlen, ok := direntNamlen(buf)
	if !ok {
		return 0, false
	}
	return (16 + namlen + 1 + 7) &^ 7, true
}

func direntNamlen(buf []byte) (uint64, bool) {
	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))
}

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

func Pipe(p []int) (err error) {
	if len(p) != 2 {
		return EINVAL
	}
	r, w, err := pipe()
	if err == nil {
		p[0], p[1] = r, w
	}
	return err
}

//sysnb	pipe2(p *[2]_C_int, flags int) (r int, w int, err error)

func Pipe2(p []int, flags int) (err error) {
	if len(p) != 2 {
		return EINVAL
	}
	var pp [2]_C_int
	// pipe2 on dragonfly takes an fds array as an argument, but still
	// returns the file descriptors.
	r, w, err := pipe2(&pp, flags)
	if err == nil {
		p[0], p[1] = r, w
	}
	return err
}

//sys	extpread(fd int, p []byte, flags int, offset int64) (n int, err error)
func Pread(fd int, p []byte, offset int64) (n int, err error) {
	return extpread(fd, p, 0, offset)
}

//sys	extpwrite(fd int, p []byte, flags int, offset int64) (n int, err error)
func Pwrite(fd int, p []byte, offset int64) (n int, err error) {
	return extpwrite(fd, p, 0, offset)
}

func Accept4(fd, flags int) (nfd int, sa Sockaddr, err error) {
	var rsa RawSockaddrAny
	var len _Socklen = SizeofSockaddrAny
	nfd, err = accept4(fd, &rsa, &len, flags)
	if err != nil {
		return
	}
	if len > SizeofSockaddrAny {
		panic("RawSockaddrAny too small")
	}
	sa, err = anyToSockaddr(&rsa)
	if err != nil {
		Close(nfd)
		nfd = 0
	}
	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_GETFSSTAT, uintptr(_p0), bufsize, uintptr(flags))
	n = int(r0)
	if e1 != 0 {
		err = e1
	}
	return
}

func setattrlistTimes(path string, times []Timespec) error {
	// used on Darwin for UtimesNano
	return ENOSYS
}

/*
 * 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	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	Fstatfs(fd int, stat *Statfs_t) (err error)
//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	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	Gettimeofday(tv *Timeval) (err error)
//sysnb	Getuid() (uid int)
//sys	Issetugid() (tainted bool)
//sys	Kill(pid int, signum Signal) (err error)
//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	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	Nanosleep(time *Timespec, leftover *Timespec) (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	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)
//sysnb	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)
//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	Statfs(path string, stat *Statfs_t) (err error)
//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
//sys	accept4(fd int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (nfd int, err error)
//sys	utimensat(dirfd int, path string, times *[2]Timespec, flag int) (err error)
//sys	getcwd(buf []byte) (n int, err error) = SYS___GETCWD
//sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) = SYS___SYSCTL