Re: Patch for handling long null terminated strings in JDBC driver

Thanks. Patch applied.

> 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);

>
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