wip

[tripe-android] / sys.scala

/* -*-scala-*-
 *
 * System calls and errors
 *
 * (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.File;

import Magic._;

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

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

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

  private[this] 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[this] 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[tripe] def this(err: Int, what: CString)
    { this(Errno(err), what.toJString); }
  override def getMessage(): String = s"$what: ${err.message}";
}

/*----- Filesystem 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 { jni.mkfile(f); return f; }
    catch { case SystemError(EEXIST, _) => (); }
  }

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

def rmTree(f: File) {
  def walk(f: File) {
    if (jni.stat(f).isdir) {
      closing(new jni.DirFilesIterator(f)) { _ foreach(walk _) }
      try { jni.rmdir(f); }
      catch { case SystemError(ENOENT, _) => (); }
    } else {
      try { jni.unlink(f); }
      catch { case SystemError(ENOENT, _) => (); }
    }
  }
  walk(f);
}
def rmTree(path: String) { rmTree(new File(path)); }

def fileExists(path: String): Boolean =
  try { jni.stat(path); true }
  catch { case SystemError(ENOENT, _) => false };
def fileExists(file: File): Boolean = fileExists(file.getPath);

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

}