Patch for handling long null terminated strings in JDBC driver - Mailing list pgsql-jdbc

The attached patch fixes problems with the JDBC driver handling long
null terminated strings.  The FE/BE protocol sends in some cases null
terminated strings to the client.  The docs for the FE/BE protocol state
that there is no limit on the size of a null terminated string sent to
the client and a client should be coded using an expanding buffer to
deal with large strings.  The old code did not do this and gave an error
if a null terminated string was greater than either 4 or 8K.  It appears
that with the advent of TOAST very long SQL statements are becoming more
common, and apparently some error messages from the backend include the
SQL statement thus easily exceeding the 8K limit in the old code.

In fixing I also cleaned up some calls in the JDBC fastpath code that
were not doing character set conversion under multibyte, and removed
some methods that were no longer needed.  I also removed a potential
threading problem with a shared variable that was being used in
Connection.java.

Thanks to Steve Wampler for discovering the problem and sending the
initial diffs that were the basis of this patch.

thanks,
--Barry
*** ./interfaces/jdbc/org/postgresql/Connection.java.orig    Thu Jul 12 13:37:28 2001
--- ./interfaces/jdbc/org/postgresql/Connection.java    Thu Jul 12 13:32:55 2001
***************
*** 82,92 ****
      public int pid;
      public int ckey;

-     // This receive_sbuf should be used by the different methods
-     // that call pg_stream.ReceiveString() in this Connection, so
-     // so we avoid uneccesary new allocations.
-     byte receive_sbuf[] = new byte[8192];
-
      /**
       * This is called by Class.forName() from within org.postgresql.Driver
       */
--- 82,87 ----
***************
*** 167,174 ****
          // The most common one to be thrown here is:
          // "User authentication failed"
          //
!         throw new SQLException(pg_stream.ReceiveString
!                                        (receive_sbuf, 4096, getEncoding()));

            case 'R':
          // Get the type of request
--- 162,168 ----
                  // The most common one to be thrown here is:
                  // "User authentication failed"
                  //
!                 throw new SQLException(pg_stream.ReceiveString(getEncoding()));

                case 'R':
                  // Get the type of request
***************
*** 238,245 ****
            break;
      case 'E':
      case 'N':
!            throw new SQLException(pg_stream.ReceiveString
!                                   (receive_sbuf, 4096, getEncoding()));
          default:
            throw new PSQLException("postgresql.con.setup");
        }
--- 232,238 ----
            break;
          case 'E':
          case 'N':
!            throw new SQLException(pg_stream.ReceiveString(getEncoding()));
          default:
            throw new PSQLException("postgresql.con.setup");
        }
***************
*** 251,257 ****
         break;
      case 'E':
      case 'N':
!            throw new SQLException(pg_stream.ReceiveString(receive_sbuf, 4096, getEncoding()));
          default:
            throw new PSQLException("postgresql.con.setup");
        }
--- 244,250 ----
             break;
          case 'E':
          case 'N':
!            throw new SQLException(pg_stream.ReceiveString(getEncoding()));
          default:
            throw new PSQLException("postgresql.con.setup");
        }
***************
*** 491,497 ****
              {
              case 'A':    // Asynchronous Notify
                  pid = pg_stream.ReceiveInteger(4);
!                 msg = pg_stream.ReceiveString(receive_sbuf,8192,getEncoding());
                  break;
              case 'B':    // Binary Data Transfer
                  if (fields == null)
--- 484,490 ----
                          {
                          case 'A':    // Asynchronous Notify
                              pid = pg_stream.ReceiveInteger(4);
!                             msg = pg_stream.ReceiveString(getEncoding());
                              break;
                          case 'B':    // Binary Data Transfer
                              if (fields == null)
***************
*** 502,508 ****
                  tuples.addElement(tup);
                  break;
              case 'C':    // Command Status
!                 recv_status = pg_stream.ReceiveString(receive_sbuf,8192,getEncoding());

                  // Now handle the update count correctly.
                  if(recv_status.startsWith("INSERT") || recv_status.startsWith("UPDATE") ||
recv_status.startsWith("DELETE")|| recv_status.startsWith("MOVE")) { 
--- 495,501 ----
                                  tuples.addElement(tup);
                              break;
                          case 'C':    // Command Status
!                             recv_status = pg_stream.ReceiveString(getEncoding());

                                  // Now handle the update count correctly.
                                  if(recv_status.startsWith("INSERT") || recv_status.startsWith("UPDATE") ||
recv_status.startsWith("DELETE")|| recv_status.startsWith("MOVE")) { 
***************
*** 544,550 ****
                  tuples.addElement(tup);
                  break;
              case 'E':    // Error Message
!                 msg = pg_stream.ReceiveString(receive_sbuf,4096,getEncoding());
                  final_error = new SQLException(msg);
                  hfr = true;
                  break;
--- 537,543 ----
                                  tuples.addElement(tup);
                              break;
                          case 'E':    // Error Message
!                             msg = pg_stream.ReceiveString(getEncoding());
                              final_error = new SQLException(msg);
                              hfr = true;
                              break;
***************
*** 559,568 ****
                  hfr = true;
                  break;
              case 'N':    // Error Notification
!                 addWarning(pg_stream.ReceiveString(receive_sbuf,4096,getEncoding()));
                  break;
              case 'P':    // Portal Name
!                 String pname = pg_stream.ReceiveString(receive_sbuf,8192,getEncoding());
                  break;
              case 'T':    // MetaData Field Description
                  if (fields != null)
--- 552,561 ----
                                  hfr = true;
                              break;
                          case 'N':    // Error Notification
!                             addWarning(pg_stream.ReceiveString(getEncoding()));
                              break;
                          case 'P':    // Portal Name
!                             String pname = pg_stream.ReceiveString(getEncoding());
                              break;
                          case 'T':    // MetaData Field Description
                              if (fields != null)
***************
*** 595,601 ****

      for (i = 0 ; i < nf ; ++i)
          {
!         String typname = pg_stream.ReceiveString(receive_sbuf,8192,getEncoding());
          int typid = pg_stream.ReceiveIntegerR(4);
          int typlen = pg_stream.ReceiveIntegerR(2);
          int typmod = pg_stream.ReceiveIntegerR(4);
--- 588,594 ----

          for (i = 0 ; i < nf ; ++i)
              {
!                 String typname = pg_stream.ReceiveString(getEncoding());
                  int typid = pg_stream.ReceiveIntegerR(4);
                  int typlen = pg_stream.ReceiveIntegerR(2);
                  int typmod = pg_stream.ReceiveIntegerR(4);
*** ./interfaces/jdbc/org/postgresql/fastpath/Fastpath.java.orig    Thu Jul 12 13:37:28 2001
--- ./interfaces/jdbc/org/postgresql/fastpath/Fastpath.java    Thu Jul 12 13:31:59 2001
***************
*** 89,95 ****
      //DriverManager.println("ReceiveChar() = "+in+" '"+((char)in)+"'");
      //if(in!='V') {
      //if(in=='E')
!     //throw new SQLException(stream.ReceiveString(4096));
      //throw new SQLException("Fastpath: expected 'V' from backend, got "+((char)in));
      //}

--- 89,95 ----
      //DriverManager.println("ReceiveChar() = "+in+" '"+((char)in)+"'");
      //if(in!='V') {
      //if(in=='E')
!     //throw new SQLException(stream.ReceiveString(conn.getEncoding()));
      //throw new SQLException("Fastpath: expected 'V' from backend, got "+((char)in));
      //}

***************
*** 123,134 ****
        //------------------------------
        // Error message returned
      case 'E':
!       throw new PSQLException("postgresql.fp.error",stream.ReceiveString(4096));

        //------------------------------
        // Notice from backend
      case 'N':
!       conn.addWarning(stream.ReceiveString(4096));
        break;

        //------------------------------
--- 123,134 ----
            //------------------------------
            // Error message returned
          case 'E':
!           throw new PSQLException("postgresql.fp.error",stream.ReceiveString(conn.getEncoding()));

            //------------------------------
            // Notice from backend
          case 'N':
!           conn.addWarning(stream.ReceiveString(conn.getEncoding()));
            break;

            //------------------------------
*** ./interfaces/jdbc/org/postgresql/PG_Stream.java.orig    Thu Jul 12 13:37:28 2001
--- ./interfaces/jdbc/org/postgresql/PG_Stream.java    Thu Jul 12 13:54:03 2001
***************
*** 23,28 ****
--- 23,29 ----
    private Socket connection;
    private InputStream pg_input;
    private BufferedOutputStream pg_output;
+   private byte[] byte_buf = new byte[8*1024];

      BytePoolDim1 bytePoolDim1 = new BytePoolDim1();
      BytePoolDim2 bytePoolDim2 = new BytePoolDim2();
***************
*** 200,271 ****
    }

    /**
!    * Receives a null-terminated string from the backend.  Maximum of
!    * maxsiz bytes - if we don't see a null, then we assume something
!    * has gone wrong.
     *
-    * @param maxsiz maximum length of string
-    * @return string from back end
-    * @exception SQLException if an I/O error occurs
-    */
-   public String ReceiveString(int maxsiz) throws SQLException
-   {
-     byte[] rst = bytePoolDim1.allocByte(maxsiz);
-     return ReceiveString(rst, maxsiz, null);
-   }
-
-   /**
-    * Receives a null-terminated string from the backend.  Maximum of
-    * maxsiz bytes - if we don't see a null, then we assume something
-    * has gone wrong.
-    *
-    * @param maxsiz maximum length of string
     * @param encoding the charset encoding to use.
-    * @param maxsiz maximum length of string in bytes
     * @return string from back end
!    * @exception SQLException if an I/O error occurs
     */
!   public String ReceiveString(int maxsiz, String encoding) throws SQLException
!   {
!     byte[] rst = bytePoolDim1.allocByte(maxsiz);
!     return ReceiveString(rst, maxsiz, encoding);
!   }
!
!   /**
!    * Receives a null-terminated string from the backend.  Maximum of
!    * maxsiz bytes - if we don't see a null, then we assume something
!    * has gone wrong.
!    *
!    * @param rst byte array to read the String into. rst.length must
!    *        equal to or greater than maxsize.
!    * @param maxsiz maximum length of string in bytes
!    * @param encoding the charset encoding to use.
!    * @return string from back end
!    * @exception SQLException if an I/O error occurs
!    */
!   public String ReceiveString(byte rst[], int maxsiz, String encoding)
        throws SQLException
    {
      int s = 0;
!
!     try
!       {
!     while (s < maxsiz)
!       {
          int c = pg_input.read();
          if (c < 0)
            throw new PSQLException("postgresql.stream.eof");
           else if (c == 0) {
           rst[s] = 0;
           break;
!          } else
            rst[s++] = (byte)c;
        }
!     if (s >= maxsiz)
!       throw new PSQLException("postgresql.stream.toomuch");
        } catch (IOException e) {
      throw new PSQLException("postgresql.stream.ioerror",e);
        }
        String v = null;
        if (encoding == null)
            v = new String(rst, 0, s);
--- 201,245 ----
    }

    /**
!    * Receives a null-terminated string from the backend.  If we don't see a
!    * null, then we assume something has gone wrong.
     *
     * @param encoding the charset encoding to use.
     * @return string from back end
!    * @exception SQLException if an I/O error occurs, or end of file
     */
!   public String ReceiveString(String encoding)
        throws SQLException
    {
      int s = 0;
!     byte[] rst = byte_buf;
!     try {
!       int buflen = rst.length;
!       boolean done = false;
!       while (!done) {
!         while (s < buflen) {
            int c = pg_input.read();
            if (c < 0)
              throw new PSQLException("postgresql.stream.eof");
            else if (c == 0) {
              rst[s] = 0;
+             done = true;
              break;
!           } else {
                rst[s++] = (byte)c;
            }
!           if (s >= buflen) { // Grow the buffer
!             buflen = (int)(buflen*2); // 100% bigger
!             byte[] newrst = new byte[buflen];
!             System.arraycopy(rst, 0, newrst, 0, s);
!             rst = newrst;
!           }
!         }
!       }
      } catch (IOException e) {
        throw new PSQLException("postgresql.stream.ioerror",e);
      }
+
      String v = null;
      if (encoding == null)
        v = new String(rst, 0, s);