// 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.

package syscall

import "unsafe"

func Getpagesize() int { return 4096 }

func TimespecToNsec(ts Timespec) int64 { return int64(ts.Sec)*1e9 + int64(ts.Nsec) }

func NsecToTimespec(nsec int64) (ts Timespec) {
	ts.Sec = int32(nsec / 1e9)
	ts.Nsec = int32(nsec % 1e9)
	return
}

func TimevalToNsec(tv Timeval) int64 { return int64(tv.Sec)*1e9 + int64(tv.Usec)*1e3 }

func NsecToTimeval(nsec int64) (tv Timeval) {
	nsec += 999 // round up to microsecond
	tv.Sec = int32(nsec / 1e9)
	tv.Usec = int32(nsec % 1e9 / 1e3)
	return
}

// 64-bit file system and 32-bit uid calls
// (386 default is 32-bit file system and 16-bit uid).
//sys	Chown(path string, uid int, gid int) (errno int) = SYS_CHOWN32
//sys	Fchown(fd int, uid int, gid int) (errno int) = SYS_FCHOWN32
//sys	Fstat(fd int, stat *Stat_t) (errno int) = SYS_FSTAT64
//sys	Getegid() (egid int) = SYS_GETEGID32
//sys	Geteuid() (euid int) = SYS_GETEUID32
//sys	Getgid() (gid int) = SYS_GETGID32
//sys	Getuid() (uid int) = SYS_GETUID32
//sys	Ioperm(from int, num int, on int) (errno int)
//sys	Iopl(level int) (errno int)
//sys	Lchown(path string, uid int, gid int) (errno int) = SYS_LCHOWN32
//sys	Lstat(path string, stat *Stat_t) (errno int) = SYS_LSTAT64
//sys	Pread(fd int, p []byte, offset int64) (n int, errno int) = SYS_PREAD64
//sys	Pwrite(fd int, p []byte, offset int64) (n int, errno int) = SYS_PWRITE64
//sys	Setfsgid(gid int) (errno int) = SYS_SETFSGID32
//sys	Setfsuid(uid int) (errno int) = SYS_SETFSUID32
//sys	Setgid(gid int) (errno int) = SYS_SETGID32
//sys	Setregid(rgid int, egid int) (errno int) = SYS_SETREGID32
//sys	Setresgid(rgid int, egid int, sgid int) (errno int) = SYS_SETRESGID32
//sys	Setresuid(ruid int, euid int, suid int) (errno int) = SYS_SETRESUID32
//sys	Setreuid(ruid int, euid int) (errno int) = SYS_SETREUID32
//sys	Stat(path string, stat *Stat_t) (errno int) = SYS_STAT64
//sys	SyncFileRange(fd int, off int64, n int64, flags int) (errno int)
//sys	getgroups(n int, list *_Gid_t) (nn int, errno int) = SYS_GETGROUPS32
//sys	setgroups(n int, list *_Gid_t) (errno int) = SYS_SETGROUPS32
//sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, errno int) = SYS__NEWSELECT

// Underlying system call writes to newoffset via pointer.
// Implemented in assembly to avoid allocation.
func Seek(fd int, offset int64, whence int) (newoffset int64, errno int)

// Vsyscalls on amd64.
//sys	Gettimeofday(tv *Timeval) (errno int)
//sys	Time(t *Time_t) (tt Time_t, errno int)

// On x86 Linux, all the socket calls go through an extra indirection,
// I think because the 5-register system call interface can't handle
// the 6-argument calls like sendto and recvfrom.  Instead the
// arguments to the underlying system call are the number below
// and a pointer to an array of uintptr.  We hide the pointer in the
// socketcall assembly to avoid allocation on every system call.

const (
	// see linux/net.h
	_SOCKET      = 1
	_BIND        = 2
	_CONNECT     = 3
	_LISTEN      = 4
	_ACCEPT      = 5
	_GETSOCKNAME = 6
	_GETPEERNAME = 7
	_SOCKETPAIR  = 8
	_SEND        = 9
	_RECV        = 10
	_SENDTO      = 11
	_RECVFROM    = 12
	_SHUTDOWN    = 13
	_SETSOCKOPT  = 14
	_GETSOCKOPT  = 15
	_SENDMSG     = 16
	_RECVMSG     = 17
)

func socketcall(call int, a0, a1, a2, a3, a4, a5 uintptr) (n int, errno int)

func accept(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (fd int, errno int) {
	fd, errno = socketcall(_ACCEPT, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), 0, 0, 0)
	return
}

func getsockname(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (errno int) {
	_, errno = socketcall(_GETSOCKNAME, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), 0, 0, 0)
	return
}

func getpeername(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (errno int) {
	_, errno = socketcall(_GETPEERNAME, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), 0, 0, 0)
	return
}

func socketpair(domain int, typ int, flags int, fd *[2]int) (errno int) {
	_, errno = socketcall(_SOCKETPAIR, uintptr(domain), uintptr(typ), uintptr(flags), uintptr(unsafe.Pointer(fd)), 0, 0)
	return
}

func bind(s int, addr uintptr, addrlen _Socklen) (errno int) {
	_, errno = socketcall(_BIND, uintptr(s), uintptr(addr), uintptr(addrlen), 0, 0, 0)
	return
}

func connect(s int, addr uintptr, addrlen _Socklen) (errno int) {
	_, errno = socketcall(_CONNECT, uintptr(s), uintptr(addr), uintptr(addrlen), 0, 0, 0)
	return
}

func socket(domain int, typ int, proto int) (fd int, errno int) {
	fd, errno = socketcall(_SOCKET, uintptr(domain), uintptr(typ), uintptr(proto), 0, 0, 0)
	return
}

func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
	_, errno = socketcall(_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
	return
}

func recvfrom(s int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, errno int) {
	var base uintptr
	if len(p) > 0 {
		base = uintptr(unsafe.Pointer(&p[0]))
	}
	n, errno = socketcall(_RECVFROM, uintptr(s), base, uintptr(len(p)), uintptr(flags), uintptr(unsafe.Pointer(from)), uintptr(unsafe.Pointer(fromlen)))
	return
}

func sendto(s int, p []byte, flags int, to uintptr, addrlen _Socklen) (errno int) {
	var base uintptr
	if len(p) > 0 {
		base = uintptr(unsafe.Pointer(&p[0]))
	}
	_, errno = socketcall(_SENDTO, uintptr(s), base, uintptr(len(p)), uintptr(flags), to, uintptr(addrlen))
	return
}

func Listen(s int, n int) (errno int) {
	_, errno = socketcall(_LISTEN, uintptr(s), uintptr(n), 0, 0, 0, 0)
	return
}

func Shutdown(s, how int) (errno int) {
	_, errno = socketcall(_SHUTDOWN, uintptr(s), uintptr(how), 0, 0, 0, 0)
	return
}

func Fstatfs(fd int, buf *Statfs_t) (errno int) {
	_, _, e1 := Syscall(SYS_FSTATFS64, uintptr(fd), uintptr(unsafe.Sizeof(*buf)), uintptr(unsafe.Pointer(buf)))
	errno = int(e1)
	return
}

func Statfs(path string, buf *Statfs_t) (errno int) {
	_, _, e1 := Syscall(SYS_STATFS64, uintptr(unsafe.Pointer(StringBytePtr(path))), uintptr(unsafe.Sizeof(*buf)), uintptr(unsafe.Pointer(buf)))
	errno = int(e1)
	return
}

func (r *PtraceRegs) PC() uint64 { return uint64(uint32(r.Eip)) }

func (r *PtraceRegs) SetPC(pc uint64) { r.Eip = int32(pc) }