shake it all up

[tripe-android] / sys.scala

/* -*-scala-*-
 *
 * System-level hacking
 *
 * (c) 2018 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of the Trivial IP Encryption (TrIPE) Android app.
 *
 * TrIPE is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your
 * option) any later version.
 *
 * TrIPE is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with TrIPE.  If not, see <https://www.gnu.org/licenses/>.
 */

package uk.org.distorted.tripe; package object sys {

/*----- Imports -----------------------------------------------------------*/

import scala.collection.mutable.HashSet;

import java.io.{Closeable, File};
import java.nio.{ByteBuffer, CharBuffer};
import java.nio.charset.Charset;
import java.util.Date;

/*----- Some magic for C strings ------------------------------------------*/

type CString = Array[Byte];

/* We do this by hand, rather than relying on the JNI's built-in conversions,
 * because we use the default encoding taken from the locale settings, rather
 * than the ridiculous `modified UTF-8' which is (a) insensitive to the
 * user's chosen locale and (b) not actually UTF-8 either.
 */

class InvalidCStringException(msg: String) extends Exception(msg);

object StringImplicits {
  implicit class ConvertJStringToCString(s: String) {
    /* Magic to convert a string into a C string (null-terminated bytes). */

    def toCString: CString = {
      /* Convert the receiver to a C string. */

      val enc = Charset.defaultCharset.newEncoder;
      val in = CharBuffer.wrap(s);
      var sz: Int = (s.length*enc.averageBytesPerChar + 1).toInt;
      var out = ByteBuffer.allocate(sz);

      while (true) {
	/* If there's still stuff to encode, then encode it.  Otherwise,
	 * there must be some dregs left in the encoder, so flush them out.
	 */
	val r = if (in.hasRemaining) enc.encode(in, out, true)
		else enc.flush(out);

	/* Sift through the wreckage to figure out what to do. */
	if (r.isError) r.throwException();
	else if (r.isOverflow) {
	  /* No space in the buffer.  Make it bigger. */

	  sz *= 2;
	  val newout = ByteBuffer.allocate(sz);
	  out.flip(); newout.put(out);
	  out = newout;
	} else if (r.isUnderflow) {
	  /* All done.  Check that there are no unexpected zero bytes -- so
	   * this will indeed be a valid C string -- and convert into a byte
	   * array that the C code will be able to pick apart.
	   */

	  out.flip(); val n = out.limit; val u = out.array;
	  if ({val z = u.indexOf(0); 0 <= z && z < n})
	    throw new InvalidCStringException("null byte in encoding");
	  val v = new Array[Byte](n + 1);
	  out.array.copyToArray(v, 0, n);
	  v(n) = 0;
	  return v;
	}
      }

      /* Placate the type checker. */
      unreachable("unreachable");
    }
  }

  implicit class ConvertCStringToJString(v: CString) {
    /* Magic to convert a C string into a `proper' string. */

    def toJString: String = {
      /* Convert the receiver to a C string.
       *
       * We do this by hand, rather than relying on the JNI's built-in
       * conversions, because we use the default encoding taken from the
       * locale settings, rather than the ridiculous `modified UTF-8' which
       * is (a) insensitive to the user's chosen locale and (b) not actually
       * UTF-8 either.
       */

      val inlen = v.indexOf(0) match {
	case -1 => v.length
	case n => n
      }
      val dec = Charset.defaultCharset.newDecoder;
      val in = ByteBuffer.wrap(v, 0, inlen);
      dec.decode(in).toString
    }
  }
}
import StringImplicits._;

/*----- Main code ---------------------------------------------------------*/

/* Import the native code library. */
System.loadLibrary("toy");

/* Exception indicating that a wrapped native object has been clobbered. */
class NativeObjectTypeException(msg: String) extends RuntimeException(msg);
type Wrapper = Array[Byte];

/*----- Error codes -------------------------------------------------------*/

protected case class ErrorEntry(val tag: String, val err: Int);
@native protected def errtab: Array[ErrorEntry];
@native protected def strerror(err: Int): CString;

object Errno extends Enumeration {
  private val tagmap = {
    val b = Map.newBuilder[String, Int];
    for (ErrorEntry(tag, err) <- errtab) b += tag -> err;
    b.result
  }
  private var wrong = -255;
  private val seen = HashSet[Int]();

  class ErrnoVal private[Errno](tag: String, val code: Int, id: Int)
	extends Val(id, tag) {
    def message: String = strerror(code).toJString;
  }

  private def err(tag: String, code: Int): ErrnoVal = {
    if (seen contains code) { wrong -= 1; new ErrnoVal(tag, code, wrong) }
    else { seen += code; new ErrnoVal(tag, code, code) }
  }
  private def err(tag: String): ErrnoVal = err(tag, tagmap(tag));

  val OK = err("OK", 0);

  /*
     ;;; The errno name table is very boring to type.  To make life less
     ;;; awful, put the errno names in this list and evaluate the code to
     ;;; get Emacs to regenerate it.

     (let ((errors '(EPERM ENOENT ESRCH EINTR EIO ENXIO E2BIG ENOEXEC EBADF
		     ECHILD EAGAIN ENOMEM EACCES EFAULT ENOTBLK EBUSY EEXIST
		     EXDEV ENODEV ENOTDIR EISDIR EINVAL ENFILE EMFILE ENOTTY
		     ETXTBSY EFBIG ENOSPC ESPIPE EROFS EMLINK EPIPE EDOM
		     ERANGE

		     EDEADLK ENAMETOOLONG ENOLCK ENOSYS ENOTEMPTY ELOOP
		     EWOULDBLOCK ENOMSG EIDRM ECHRNG EL2NSYNC EL3HLT EL3RST
		     ELNRNG EUNATCH ENOCSI EL2HLT EBADE EBADR EXFULL ENOANO
		     EBADRQC EBADSLT EDEADLOCK EBFONT ENOSTR ENODATA ETIME
		     ENOSR ENONET ENOPKG EREMOTE ENOLINK EADV ESRMNT ECOMM
		     EPROTO EMULTIHOP EDOTDOT EBADMSG EOVERFLOW ENOTUNIQ
		     EBADFD EREMCHG ELIBACC ELIBBAD ELIBSCN ELIBMAX ELIBEXEC
		     EILSEQ ERESTART ESTRPIPE EUSERS ENOTSOCK EDESTADDRREQ
		     EMSGSIZE EPROTOTYPE ENOPROTOOPT EPROTONOSUPPORT
		     ESOCKTNOSUPPORT EOPNOTSUPP EPFNOSUPPORT EAFNOSUPPORT
		     EADDRINUSE EADDRNOTAVAIL ENETDOWN ENETUNREACH ENETRESET
		     ECONNABORTED ECONNRESET ENOBUFS EISCONN ENOTCONN
		     ESHUTDOWN ETOOMANYREFS ETIMEDOUT ECONNREFUSED EHOSTDOWN
		     EHOSTUNREACH EALREADY EINPROGRESS ESTALE EUCLEAN ENOTNAM
		     ENAVAIL EISNAM EREMOTEIO EDQUOT ENOMEDIUM EMEDIUMTYPE
		     ECANCELED ENOKEY EKEYEXPIRED EKEYREVOKED EKEYREJECTED
		     EOWNERDEAD ENOTRECOVERABLE ERFKILL EHWPOISON)))
       (save-excursion
	 (goto-char (point-min))
	 (search-forward (concat "***" "BEGIN errtab" "***"))
	 (beginning-of-line 2)
	 (delete-region (point)
			(progn
			  (search-forward "***END***")
			  (beginning-of-line)
			  (point)))
	 (dolist (err errors)
	   (insert (format "  val %s = err(\"%s\");\n" err err)))))
  */
  /***BEGIN errtab***/
  val EPERM = err("EPERM");
  val ENOENT = err("ENOENT");
  val ESRCH = err("ESRCH");
  val EINTR = err("EINTR");
  val EIO = err("EIO");
  val ENXIO = err("ENXIO");
  val E2BIG = err("E2BIG");
  val ENOEXEC = err("ENOEXEC");
  val EBADF = err("EBADF");
  val ECHILD = err("ECHILD");
  val EAGAIN = err("EAGAIN");
  val ENOMEM = err("ENOMEM");
  val EACCES = err("EACCES");
  val EFAULT = err("EFAULT");
  val ENOTBLK = err("ENOTBLK");
  val EBUSY = err("EBUSY");
  val EEXIST = err("EEXIST");
  val EXDEV = err("EXDEV");
  val ENODEV = err("ENODEV");
  val ENOTDIR = err("ENOTDIR");
  val EISDIR = err("EISDIR");
  val EINVAL = err("EINVAL");
  val ENFILE = err("ENFILE");
  val EMFILE = err("EMFILE");
  val ENOTTY = err("ENOTTY");
  val ETXTBSY = err("ETXTBSY");
  val EFBIG = err("EFBIG");
  val ENOSPC = err("ENOSPC");
  val ESPIPE = err("ESPIPE");
  val EROFS = err("EROFS");
  val EMLINK = err("EMLINK");
  val EPIPE = err("EPIPE");
  val EDOM = err("EDOM");
  val ERANGE = err("ERANGE");
  val EDEADLK = err("EDEADLK");
  val ENAMETOOLONG = err("ENAMETOOLONG");
  val ENOLCK = err("ENOLCK");
  val ENOSYS = err("ENOSYS");
  val ENOTEMPTY = err("ENOTEMPTY");
  val ELOOP = err("ELOOP");
  val EWOULDBLOCK = err("EWOULDBLOCK");
  val ENOMSG = err("ENOMSG");
  val EIDRM = err("EIDRM");
  val ECHRNG = err("ECHRNG");
  val EL2NSYNC = err("EL2NSYNC");
  val EL3HLT = err("EL3HLT");
  val EL3RST = err("EL3RST");
  val ELNRNG = err("ELNRNG");
  val EUNATCH = err("EUNATCH");
  val ENOCSI = err("ENOCSI");
  val EL2HLT = err("EL2HLT");
  val EBADE = err("EBADE");
  val EBADR = err("EBADR");
  val EXFULL = err("EXFULL");
  val ENOANO = err("ENOANO");
  val EBADRQC = err("EBADRQC");
  val EBADSLT = err("EBADSLT");
  val EDEADLOCK = err("EDEADLOCK");
  val EBFONT = err("EBFONT");
  val ENOSTR = err("ENOSTR");
  val ENODATA = err("ENODATA");
  val ETIME = err("ETIME");
  val ENOSR = err("ENOSR");
  val ENONET = err("ENONET");
  val ENOPKG = err("ENOPKG");
  val EREMOTE = err("EREMOTE");
  val ENOLINK = err("ENOLINK");
  val EADV = err("EADV");
  val ESRMNT = err("ESRMNT");
  val ECOMM = err("ECOMM");
  val EPROTO = err("EPROTO");
  val EMULTIHOP = err("EMULTIHOP");
  val EDOTDOT = err("EDOTDOT");
  val EBADMSG = err("EBADMSG");
  val EOVERFLOW = err("EOVERFLOW");
  val ENOTUNIQ = err("ENOTUNIQ");
  val EBADFD = err("EBADFD");
  val EREMCHG = err("EREMCHG");
  val ELIBACC = err("ELIBACC");
  val ELIBBAD = err("ELIBBAD");
  val ELIBSCN = err("ELIBSCN");
  val ELIBMAX = err("ELIBMAX");
  val ELIBEXEC = err("ELIBEXEC");
  val EILSEQ = err("EILSEQ");
  val ERESTART = err("ERESTART");
  val ESTRPIPE = err("ESTRPIPE");
  val EUSERS = err("EUSERS");
  val ENOTSOCK = err("ENOTSOCK");
  val EDESTADDRREQ = err("EDESTADDRREQ");
  val EMSGSIZE = err("EMSGSIZE");
  val EPROTOTYPE = err("EPROTOTYPE");
  val ENOPROTOOPT = err("ENOPROTOOPT");
  val EPROTONOSUPPORT = err("EPROTONOSUPPORT");
  val ESOCKTNOSUPPORT = err("ESOCKTNOSUPPORT");
  val EOPNOTSUPP = err("EOPNOTSUPP");
  val EPFNOSUPPORT = err("EPFNOSUPPORT");
  val EAFNOSUPPORT = err("EAFNOSUPPORT");
  val EADDRINUSE = err("EADDRINUSE");
  val EADDRNOTAVAIL = err("EADDRNOTAVAIL");
  val ENETDOWN = err("ENETDOWN");
  val ENETUNREACH = err("ENETUNREACH");
  val ENETRESET = err("ENETRESET");
  val ECONNABORTED = err("ECONNABORTED");
  val ECONNRESET = err("ECONNRESET");
  val ENOBUFS = err("ENOBUFS");
  val EISCONN = err("EISCONN");
  val ENOTCONN = err("ENOTCONN");
  val ESHUTDOWN = err("ESHUTDOWN");
  val ETOOMANYREFS = err("ETOOMANYREFS");
  val ETIMEDOUT = err("ETIMEDOUT");
  val ECONNREFUSED = err("ECONNREFUSED");
  val EHOSTDOWN = err("EHOSTDOWN");
  val EHOSTUNREACH = err("EHOSTUNREACH");
  val EALREADY = err("EALREADY");
  val EINPROGRESS = err("EINPROGRESS");
  val ESTALE = err("ESTALE");
  val EUCLEAN = err("EUCLEAN");
  val ENOTNAM = err("ENOTNAM");
  val ENAVAIL = err("ENAVAIL");
  val EISNAM = err("EISNAM");
  val EREMOTEIO = err("EREMOTEIO");
  val EDQUOT = err("EDQUOT");
  val ENOMEDIUM = err("ENOMEDIUM");
  val EMEDIUMTYPE = err("EMEDIUMTYPE");
  val ECANCELED = err("ECANCELED");
  val ENOKEY = err("ENOKEY");
  val EKEYEXPIRED = err("EKEYEXPIRED");
  val EKEYREVOKED = err("EKEYREVOKED");
  val EKEYREJECTED = err("EKEYREJECTED");
  val EOWNERDEAD = err("EOWNERDEAD");
  val ENOTRECOVERABLE = err("ENOTRECOVERABLE");
  val ERFKILL = err("ERFKILL");
  val EHWPOISON = err("EHWPOISON");
  /***end***/
}
import Errno.{Value => _, _};

object SystemError {
  def apply(err: Errno.Value, what: String): SystemError =
    new SystemError(err, what);
  def unapply(e: Exception): Option[(Errno.Value, String)] = e match {
    case e: SystemError => Some((e.err, e.what))
    case _ => None
  }
}

class SystemError private[this](val err: Errno.ErrnoVal, val what: String)
	extends Exception {
  def this(err: Errno.Value, what: String)
    { this(err.asInstanceOf[Errno.ErrnoVal], what); }
  private def this(err: Int, what: CString)
    { this(Errno(err), what.toJString); }
  override def getMessage(): String = s"$what: ${err.message}";
}

/*----- Basic file operations ---------------------------------------------*/

@native protected def unlink(path: CString);
def unlink(path: String) { unlink(path.toCString); }
@native protected def rmdir(path: CString);
def rmdir(path: String) { rmdir(path.toCString); }
@native protected def mkdir(path: CString, mode: Int);
def mkdir(path: String, mode: Int) { mkdir(path.toCString, mode); }
@native protected def mkfile(path: CString, mode: Int);
def mkfile(path: String, mode: Int) { mkfile(path.toCString, mode); }
@native protected def rename(from: CString, to: CString);
def rename(from: String, to: String)
  { rename(from.toCString, to.toCString); }

/*----- File status information -------------------------------------------*/

/* These are the traditional values, but the C code carefully arranges to
 * return them regardless of what your kernel actually thinks.
 */
val S_IFMT = 0xf000;
val S_IFIFO = 0x1000;
val S_IFCHR = 0x2000;
val S_IFDIR = 0x4000;
val S_IFBLK = 0x6000;
val S_IFREG = 0x8000;
val S_IFLNK = 0xa000;
val S_IFSOCK = 0xc000;

@native protected def stat(path: CString): sys.FileInfo;
def stat(path: String): sys.FileInfo = stat(path.toCString);
@native protected def lstat(path: CString): sys.FileInfo;
def lstat(path: String): sys.FileInfo = lstat(path.toCString);

object FileInfo extends Enumeration {
  val FIFO, CHR, DIR, BLK, REG, LNK, SOCK, UNK = Value;
  type Type = Value;
}
import FileInfo._;


class FileInfo private[this](val devMajor: Int, val devMinor: Int,
			     val ino: Long, val mode: Int, val nlink: Int,
			     val uid: Int, val gid: Int,
			     _rdevMinor: Int, _rdevMajor: Int,
			     val size: Long,
			     val blksize: Int, val blocks: Long,
			     val atime: Date, val mtime: Date,
			     val ctime: Date) {
  private def this(devMajor: Int, devMinor: Int, ino: Long,
		   mode: Int, nlink: Int, uid: Int, gid: Int,
		   rdevMinor: Int, rdevMajor: Int,
		   size: Long, blksize: Int, blocks: Long,
		   atime: Long, mtime: Long, ctime: Long) {
    this(devMajor, devMinor, ino, mode, nlink, uid, gid,
	 rdevMajor, rdevMinor, size, blksize, blocks,
	 new Date(atime), new Date(mtime), new Date(ctime));
  }

  def perms: Int = mode&0xfff;

  def ftype: Type = (mode&S_IFMT) match {
    case S_IFIFO => FIFO
    case S_IFCHR => CHR
    case S_IFDIR => DIR
    case S_IFBLK => BLK
    case S_IFREG => REG
    case S_IFLNK => LNK
    case S_IFSOCK => SOCK
    case _ => UNK
  }

  private[this] def mustBeDevice() {
    ftype match {
      case CHR | BLK => ();
      case _ => throw new IllegalArgumentException("Object is not a device");
    }
  }
  def rdevMajor: Int = { mustBeDevice(); _rdevMajor }
  def rdevMinor: Int = { mustBeDevice(); _rdevMinor }
}

/*----- Listing directories -----------------------------------------------*/

@native protected def opendir(path: CString): Wrapper;
@native protected def readdir(path: CString, dir: Wrapper): CString;
@native protected def closedir(path: CString, dir: Wrapper);

protected abstract class BaseDirIterator[T](cpath: CString)
	extends LookaheadIterator[T] with Closeable {
  def this(path: String) { this(path.toCString); }
  def this(dir: File) { this(dir.getPath); }
  override def close() { closedir(cpath, dir); }
  override protected def finalize() { super.finalize(); close(); }
  private[this] val dir = opendir(cpath);
  protected def mangle(file: String): T;
  override protected def fetch(): Option[T] = readdir(cpath, dir) match {
    case null => None
    case f => f.toJString match {
      case "." | ".." => fetch()
      case jf => Some(mangle(jf))
    }
  }
}

class DirIterator(val path: String) extends BaseDirIterator[String](path) {
  def this(dir: File) { this(dir.getPath); }
  override protected def mangle(file: String): String = file;
}

class DirFilesIterator private[this](val dir: File, cpath: CString)
	extends BaseDirIterator[File](cpath) {
  def this(dir: File) { this(dir, dir.getPath.toCString); }
  def this(path: String) { this(new File(path), path.toCString); }
  override protected def mangle(file: String): File = new File(dir, file);
}

/*----- File locking ------------------------------------------------------*/

val LKF_EXCL = 1;
val LKF_WAIT = 2;
@native protected def lock(path: CString, flags: Int): Wrapper;
@native protected def unlock(lock: Wrapper);

class FileLock(path: String, flags: Int) extends Closeable {
  def this(file: File, flags: Int) { this(file.getPath, flags); }
  def this(path: String) { this(path, LKF_EXCL); }
  def this(file: File) { this(file.getPath, LKF_EXCL); }
  private[this] val lk = lock(path.toCString, flags);
  override def close() { unlock(lk); }
  override protected def finalize() { super.finalize(); close(); }
}

/*----- File implicits ----------------------------------------------------*/

object FileImplicits {
  implicit class FileOps(file: File) {

    def unlink_!() { unlink(file.getPath); }
    def rmdir_!() { rmdir(file.getPath); }
    def mkdir_!(mode: Int) { mkdir(file.getPath, mode); }
    def mkdir_!() { mkdir_!(0x1ff); }
    def mkfile_!(mode: Int) { mkfile(file.getPath, mode); }
    def mkfile_!() { mkfile_!(0x1b6); }

    def withFilesIterator[T](body: DirFilesIterator => T): T = {
      val iter = new DirFilesIterator(file.getPath);
      try { body(iter) } finally { iter.close(); }
    }
    def files_! : Seq[File] = withFilesIterator { _.toSeq };

    def stat_! : FileInfo = stat(file.getPath);
    def lstat_! : FileInfo = lstat(file.getPath);

    private[this] def statish[T](statfn: String => FileInfo,
				 ifexists: FileInfo => T,
				 ifmissing: => T): T =
      (try { statfn(file.getPath) }
       catch { case SystemError(ENOENT, _) => null }) match {
	case null => ifmissing
	case st => ifexists(st)
      };
    def exists_! : Boolean = statish(stat _, _ => true, false);
    def isfifo_! : Boolean = statish(stat _, _.ftype == FIFO, false);
    def isblk_! : Boolean = statish(stat _, _.ftype == BLK, false);
    def isdir_! : Boolean = statish(stat _, _.ftype == DIR, false);
    def ischr_! : Boolean = statish(stat _, _.ftype == CHR, false);
    def isreg_! : Boolean = statish(stat _, _.ftype == REG, false);
    def islnk_! : Boolean = statish(lstat _, _.ftype == LNK, false);
    def issock_! : Boolean = statish(stat _, _.ftype == SOCK, false);

    def remove_!() {
      while (true) {
	try { unlink_!(); return }
	catch {
	  case SystemError(ENOENT, _) => return;
	  case SystemError(EISDIR, _) => ();
	}
	try { rmdir_!(); return }
	catch {
	  case SystemError(ENOENT, _) => return;
	  case SystemError(ENOTDIR, _) => ();
	}
      }
    }

    def rmTree() {
      def walk(f: File) {
	if (f.isdir_!) f.withFilesIterator { _ foreach(walk _) };
	f.remove_!();
      }
      walk(file);
    }

    def withLock[T](flags: Int)(body: => T): T = {
      val lk = new FileLock(file.getPath, flags);
      try { body } finally { lk.close(); }
    }
    def withLock[T](body: => T): T = withLock(LKF_EXCL) { body };
  }
}
import FileImplicits._;

/*----- Miscellaneous file hacks ------------------------------------------*/

def freshFile(d: File): File = {
  /* Return the name of a freshly created file in directory D. */

  val buf = new Array[Byte](6);
  val b = new StringBuilder;

  while (true) {
    /* Keep going until we find a fresh one. */

    /* Provide a prefix.  Mostly this is to prevent the file starting with
     * an unfortunate character like `-'.
     */
    b ++= "tmp.";

    /* Generate some random bytes. */
    rng.nextBytes(buf);

    /* Now turn the bytes into a filename.  This is a cheesy implementation
     * of Base64 encoding.
     */
    var a = 0;
    var n = 0;

    for (x <- buf) {
      a = (a << 8) | x; n += 8;
      while (n >= 6) {
	val y = (a >> n - 6)&0x3f; n -= 6;
	b += (if (y < 26) 'A' + y
	      else if (y < 52) 'a' + (y - 26)
	      else if (y < 62) '0' + (y - 52)
	      else if (y == 62) '+'
	      else '-').toChar;
      }
    }

    /* Make the filename, and try to create the file.  If we succeed, we
     * win.
     */
    val f = new File(d, b.result); b.clear();
    try { f.mkfile_!(); return f; }
    catch { case SystemError(EEXIST, _) => (); }
  }

  /* We shouldn't get here, but the type checker needs placating. */
  unreachable("unreachable");
}

/*----- Connecting to a server --------------------------------------------*/

val CF_CLOSERD = 1;
val CF_CLOSEWR = 2;
val CF_CLOSEMASK = CF_CLOSERD | CF_CLOSEWR;
@native protected def connect(path: CString): Wrapper;
@native protected def send(conn: Wrapper, buf: CString,
			   start: Int, len: Int);
@native protected def recv(conn: Wrapper, buf: CString,
			   start: Int, len: Int): Int;
@native def closeconn(conn: Wrapper, how: Int);

class Connection(path: String) extends Closeable {
  def this(file: File) { this(file.getPath); }
  private[this] val conn = connect(path.toCString);
  override def close() { closeconn(conn, CF_CLOSEMASK); }
  override protected def finalize() { super.finalize(); close(); }

  class InputStream private[Connection] extends java.io.InputStream {
    override def read(): Int = {
      val buf = new Array[Byte](1);
      val n = read(buf, 0, 1);
      if (n < 0) -1 else buf(0)&0xff;
    }
    override def read(buf: Array[Byte]): Int =
      read(buf, 0, buf.length);
    override def read(buf: Array[Byte], start: Int, len: Int) =
      recv(conn, buf, start, len);
    override def close() { closeconn(conn, CF_CLOSERD); }
  }
  lazy val input = new InputStream;

  class OutputStream private[Connection] extends java.io.OutputStream {
    override def write(b: Int) { write(Array[Byte](b.toByte), 0, 1); }
    override def write(buf: Array[Byte]) { write(buf, 0, buf.length); }
    override def write(buf: Array[Byte], start: Int, len: Int)
      { send(conn, buf, start, len); }
    override def close() { closeconn(conn, CF_CLOSEWR); }
  }
  lazy val output = new OutputStream;
}

/*----- Crypto-library hacks ----------------------------------------------*/

@native def hashsz(hash: String): Int;
      /* Return the output hash size for the named HASH function, or -1. */

/*----- That's all, folks -------------------------------------------------*/

}