text: // 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.
  
  // +build arm,linux
  
  package unix
  
  import (
  	"syscall"
  	"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 NsecToTimeval(nsec int64) (tv Timeval) {
  	nsec += 999 // round up to microsecond
  	tv.Sec = int32(nsec / 1e9)
  	tv.Usec = int32(nsec % 1e9 / 1e3)
  	return
  }
  
  func Pipe(p []int) (err error) {
  	if len(p) != 2 {
  		return EINVAL
  	}
  	var pp [2]_C_int
  	err = pipe2(&pp, 0)
  	p[0] = int(pp[0])
  	p[1] = int(pp[1])
  	return
  }
  
  //sysnb pipe2(p *[2]_C_int, flags int) (err error)
  
  func Pipe2(p []int, flags int) (err error) {
  	if len(p) != 2 {
  		return EINVAL
  	}
  	var pp [2]_C_int
  	err = pipe2(&pp, flags)
  	p[0] = int(pp[0])
  	p[1] = int(pp[1])
  	return
  }
  
  // Underlying system call writes to newoffset via pointer.
  // Implemented in assembly to avoid allocation.
  func seek(fd int, offset int64, whence int) (newoffset int64, err syscall.Errno)
  
  func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
  	newoffset, errno := seek(fd, offset, whence)
  	if errno != 0 {
  		return 0, errno
  	}
  	return newoffset, nil
  }
  
  //sys	accept(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (fd int, err error)
  //sys	accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error)
  //sys	bind(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
  //sys	connect(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
  //sysnb	getgroups(n int, list *_Gid_t) (nn int, err error) = SYS_GETGROUPS32
  //sysnb	setgroups(n int, list *_Gid_t) (err error) = SYS_SETGROUPS32
  //sys	getsockopt(s int, level int, name int, val unsafe.Pointer, vallen *_Socklen) (err error)
  //sys	setsockopt(s int, level int, name int, val unsafe.Pointer, vallen uintptr) (err error)
  //sysnb	socket(domain int, typ int, proto int) (fd int, err error)
  //sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
  //sysnb	getsockname(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
  //sys	recvfrom(fd int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, err error)
  //sys	sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
  //sysnb	socketpair(domain int, typ int, flags int, fd *[2]int32) (err error)
  //sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error)
  //sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error)
  
  // 64-bit file system and 32-bit uid calls
  // (16-bit uid calls are not always supported in newer kernels)
  //sys	Dup2(oldfd int, newfd int) (err error)
  //sys	Fchown(fd int, uid int, gid int) (err error) = SYS_FCHOWN32
  //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
  //sysnb	Getegid() (egid int) = SYS_GETEGID32
  //sysnb	Geteuid() (euid int) = SYS_GETEUID32
  //sysnb	Getgid() (gid int) = SYS_GETGID32
  //sysnb	Getuid() (uid int) = SYS_GETUID32
  //sysnb	InotifyInit() (fd int, err error)
  //sys	Lchown(path string, uid int, gid int) (err error) = SYS_LCHOWN32
  //sys	Listen(s int, n int) (err error)
  //sys	Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
  //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) = SYS_SENDFILE64
  //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) = SYS__NEWSELECT
  //sys	Setfsgid(gid int) (err error) = SYS_SETFSGID32
  //sys	Setfsuid(uid int) (err error) = SYS_SETFSUID32
  //sysnb	Setregid(rgid int, egid int) (err error) = SYS_SETREGID32
  //sysnb	Setresgid(rgid int, egid int, sgid int) (err error) = SYS_SETRESGID32
  //sysnb	Setresuid(ruid int, euid int, suid int) (err error) = SYS_SETRESUID32
  //sysnb	Setreuid(ruid int, euid int) (err error) = SYS_SETREUID32
  //sys	Shutdown(fd int, how int) (err error)
  //sys	Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error)
  //sys	Stat(path string, stat *Stat_t) (err error) = SYS_STAT64
  
  // Vsyscalls on amd64.
  //sysnb	Gettimeofday(tv *Timeval) (err error)
  //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
  //sys	Pause() (err error)
  
  func Time(t *Time_t) (Time_t, error) {
  	var tv Timeval
  	err := Gettimeofday(&tv)
  	if err != nil {
  		return 0, err
  	}
  	if t != nil {
  		*t = Time_t(tv.Sec)
  	}
  	return Time_t(tv.Sec), nil
  }
  
  func Utime(path string, buf *Utimbuf) error {
  	tv := []Timeval{
  		{Sec: buf.Actime},
  		{Sec: buf.Modtime},
  	}
  	return Utimes(path, tv)
  }
  
  //sys   Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
  //sys   Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
  //sys	Truncate(path string, length int64) (err error) = SYS_TRUNCATE64
  //sys	Ftruncate(fd int, length int64) (err error) = SYS_FTRUNCATE64
  
  func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
  	_, _, e1 := Syscall6(SYS_ARM_FADVISE64_64, uintptr(fd), uintptr(advice), uintptr(offset), uintptr(offset>>32), uintptr(length), uintptr(length>>32))
  	if e1 != 0 {
  		err = errnoErr(e1)
  	}
  	return
  }
  
  //sys	mmap2(addr uintptr, length uintptr, prot int, flags int, fd int, pageOffset uintptr) (xaddr uintptr, err error)
  
  func Fstatfs(fd int, buf *Statfs_t) (err error) {
  	_, _, e := Syscall(SYS_FSTATFS64, uintptr(fd), unsafe.Sizeof(*buf), uintptr(unsafe.Pointer(buf)))
  	if e != 0 {
  		err = e
  	}
  	return
  }
  
  func Statfs(path string, buf *Statfs_t) (err error) {
  	pathp, err := BytePtrFromString(path)
  	if err != nil {
  		return err
  	}
  	_, _, e := Syscall(SYS_STATFS64, uintptr(unsafe.Pointer(pathp)), unsafe.Sizeof(*buf), uintptr(unsafe.Pointer(buf)))
  	if e != 0 {
  		err = e
  	}
  	return
  }
  
  func mmap(addr uintptr, length uintptr, prot int, flags int, fd int, offset int64) (xaddr uintptr, err error) {
  	page := uintptr(offset / 4096)
  	if offset != int64(page)*4096 {
  		return 0, EINVAL
  	}
  	return mmap2(addr, length, prot, flags, fd, page)
  }
  
  type rlimit32 struct {
  	Cur uint32
  	Max uint32
  }
  
  //sysnb getrlimit(resource int, rlim *rlimit32) (err error) = SYS_UGETRLIMIT
  
  const rlimInf32 = ^uint32(0)
  const rlimInf64 = ^uint64(0)
  
  func Getrlimit(resource int, rlim *Rlimit) (err error) {
  	err = prlimit(0, resource, nil, rlim)
  	if err != ENOSYS {
  		return err
  	}
  
  	rl := rlimit32{}
  	err = getrlimit(resource, &rl)
  	if err != nil {
  		return
  	}
  
  	if rl.Cur == rlimInf32 {
  		rlim.Cur = rlimInf64
  	} else {
  		rlim.Cur = uint64(rl.Cur)
  	}
  
  	if rl.Max == rlimInf32 {
  		rlim.Max = rlimInf64
  	} else {
  		rlim.Max = uint64(rl.Max)
  	}
  	return
  }
  
  //sysnb setrlimit(resource int, rlim *rlimit32) (err error) = SYS_SETRLIMIT
  
  func Setrlimit(resource int, rlim *Rlimit) (err error) {
  	err = prlimit(0, resource, rlim, nil)
  	if err != ENOSYS {
  		return err
  	}
  
  	rl := rlimit32{}
  	if rlim.Cur == rlimInf64 {
  		rl.Cur = rlimInf32
  	} else if rlim.Cur < uint64(rlimInf32) {
  		rl.Cur = uint32(rlim.Cur)
  	} else {
  		return EINVAL
  	}
  	if rlim.Max == rlimInf64 {
  		rl.Max = rlimInf32
  	} else if rlim.Max < uint64(rlimInf32) {
  		rl.Max = uint32(rlim.Max)
  	} else {
  		return EINVAL
  	}
  
  	return setrlimit(resource, &rl)
  }
  
  func (r *PtraceRegs) PC() uint64 { return uint64(r.Uregs[15]) }
  
  func (r *PtraceRegs) SetPC(pc uint64) { r.Uregs[15] = uint32(pc) }
  
  func (iov *Iovec) SetLen(length int) {
  	iov.Len = uint32(length)
  }
  
  func (msghdr *Msghdr) SetControllen(length int) {
  	msghdr.Controllen = uint32(length)
  }
  
  func (cmsg *Cmsghdr) SetLen(length int) {
  	cmsg.Len = uint32(length)
  }
  
  //sys	poll(fds *PollFd, nfds int, timeout int) (n int, err error)
  
  func Poll(fds []PollFd, timeout int) (n int, err error) {
  	if len(fds) == 0 {
  		return poll(nil, 0, timeout)
  	}
  	return poll(&fds[0], len(fds), timeout)
  }
  