예제 #1
0
  /** @inheritDoc */
  public int writeBuf(int fd, byte buffer[], int off, int len) throws IOException {
    int result = 0;
    byte[] buf = buffer;
    if (off != 0) {
      buf = new byte[len];
      System.arraycopy(buffer, off, buf, 0, len);
    }

    if (DEBUG) {
      System.err.println("writeBuf(" + fd + ") before write.");
    }

    result = libc.write(fd, buf, len); // We rely on open0() for setting the socket to non-blocking

    if (result < 0) {
      int err_code = LibCUtil.errno();
      if (err_code == LibC.EWOULDBLOCK) {
        VMThread.getSystemEvents().waitForWriteEvent(fd);
        if (DEBUG) {
          System.err.println("writeBuf(" + fd + ") returned from select. retry.");
        }
        result =
            libc.write(fd, buf, len); // We rely on open0() for setting the socket to non-blocking
      }
      if (DEBUG) {
        System.err.println("writeBuf(" + fd + ") error:");
      }
      LibCUtil.errCheckNeg(result);
    }

    return result;
  }
예제 #2
0
  /** @inheritDoc */
  public int readBuf(int fd, byte b[], int offset, int length) throws IOException {
    byte[] buf = b;
    int result;

    if (offset != 0) {
      if (DEBUG) {
        System.err.println("readBuf() into temp buf");
      }
      buf = new byte[length];
    }

    if (NBIO_WORKS) {
      result =
          libc.read(fd, buf, length); // We rely on open0() for setting the socket to non-blocking
      if (result < 0) {
        int err_code = LibCUtil.errno();
        if (err_code == LibC.EWOULDBLOCK) {
          if (DEBUG) {
            System.err.println("Wait for read in select...");
          }
          VMThread.getSystemEvents().waitForReadEvent(fd);
          result =
              libc.read(
                  fd, buf, length); // We rely on open0() for setting the socket to non-blocking
        }
        LibCUtil.errCheckNeg(result);
      }
    } else {
      // If non-blocking IO doesn't seems to be working, try this hack...

      int bAvail = available(fd); // may throw IOException

      if (bAvail == 0) {
        if (DEBUG) {
          System.err.println("Wait for read in select...");
        }
        VMThread.getSystemEvents().waitForReadEvent(fd);
        bAvail = available(fd);
        if (bAvail == 0) { // woke up because connection is closed
          if (DEBUG) {
            System.err.println("readBuf(" + fd + ") signalling EOF.");
          }
          return -1; // signal EOF
        }
      }
      if (DEBUG) {
        System.err.println("readBuf(" + fd + ") returned from select. retry.");
      }

      int n = Math.min(bAvail, length); // don't read more than is asked for...
      result = libc.read(fd, buf, n); // only read what we know is there...
      LibCUtil.errCheckNeg(result);
    }

    if (result == 0) {
      // If remote side has shut down the connection gracefully, and all
      // data has been received, recv() will complete immediately with
      // zero bytes received.
      //
      // This is true for Win32/CE and Linux
      if (DEBUG) {
        System.err.println("readBuf(" + fd + ") saw remote side shutdown.");
      }
      result = -1;
    }

    if (offset != 0 && result > 0) {
      System.arraycopy(buf, 0, b, offset, result);
    }
    if (DEBUG) {
      System.out.println("readBuf(" + fd + ") = " + result);
    }

    return result;
  }