text: /*-------------------------------------------------------------------------
   *
   * fe-protocol2.c
   *	  functions that are specific to frontend/backend protocol version 2
   *
   * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   *
   * IDENTIFICATION
   *	  src/interfaces/libpq/fe-protocol2.c
   *
   *-------------------------------------------------------------------------
   */
  
  /*
   * This file is compiled with both frontend and backend codes, symlinked by
   * src/backend/Makefile, and use macro FRONTEND to switch.
   *
   * Include "c.h" to adopt Greenplum C types. Don't include "postgres_fe.h",
   * which only defines FRONTEND besides including "c.h"
   */
  #include "c.h"
  
  #include <ctype.h>
  #include <fcntl.h>
  
  #include "libpq-fe.h"
  #include "libpq-int.h"
  
  
  #ifdef WIN32
  #include "win32.h"
  #else
  #include <unistd.h>
  #include <netinet/in.h>
  #ifdef HAVE_NETINET_TCP_H
  #include <netinet/tcp.h>
  #endif
  #include <arpa/inet.h>
  #endif
  
  
  static int	getRowDescriptions(PGconn *conn);
  static int	getAnotherTuple(PGconn *conn, bool binary);
  static int	pqGetErrorNotice2(PGconn *conn, bool isError);
  static void checkXactStatus(PGconn *conn, const char *cmdTag);
  static int	getNotify(PGconn *conn);
  
  
  /*
   *		pqSetenvPoll
   *
   * Polls the process of passing the values of a standard set of environment
   * variables to the backend.
   */
  PostgresPollingStatusType
  pqSetenvPoll(PGconn *conn)
  {
  	PGresult   *res;
  
  	if (conn == NULL || conn->status == CONNECTION_BAD)
  		return PGRES_POLLING_FAILED;
  
  	/* Check whether there are any data for us */
  	switch (conn->setenv_state)
  	{
  			/* These are reading states */
  		case SETENV_STATE_CLIENT_ENCODING_WAIT:
  		case SETENV_STATE_OPTION_WAIT:
  		case SETENV_STATE_QUERY1_WAIT:
  		case SETENV_STATE_QUERY2_WAIT:
  			{
  				/* Load waiting data */
  				int			n = pqReadData(conn);
  
  				if (n < 0)
  					goto error_return;
  				if (n == 0)
  					return PGRES_POLLING_READING;
  
  				break;
  			}
  
  			/* These are writing states, so we just proceed. */
  		case SETENV_STATE_CLIENT_ENCODING_SEND:
  		case SETENV_STATE_OPTION_SEND:
  		case SETENV_STATE_QUERY1_SEND:
  		case SETENV_STATE_QUERY2_SEND:
  			break;
  
  			/* Should we raise an error if called when not active? */
  		case SETENV_STATE_IDLE:
  			return PGRES_POLLING_OK;
  
  		default:
  			printfPQExpBuffer(&conn->errorMessage,
  							  libpq_gettext(
  											"invalid setenv state %c, "
  								 "probably indicative of memory corruption\n"
  											),
  							  conn->setenv_state);
  			goto error_return;
  	}
  
  	/* We will loop here until there is nothing left to do in this call. */
  	for (;;)
  	{
  		switch (conn->setenv_state)
  		{
  				/*
  				 * The _CLIENT_ENCODING_SEND code is slightly different from
  				 * _OPTION_SEND below (e.g., no getenv() call), which is why a
  				 * different state is used.
  				 */
  			case SETENV_STATE_CLIENT_ENCODING_SEND:
  				{
  					char		setQuery[100];	/* note length limit in
  												 * sprintf below */
  					const char *val = conn->client_encoding_initial;
  
  					if (val)
  					{
  						if (pg_strcasecmp(val, "default") == 0)
  							sprintf(setQuery, "SET client_encoding = DEFAULT");
  						else
  							sprintf(setQuery, "SET client_encoding = '%.60s'",
  									val);
  #ifdef CONNECTDEBUG
  						fprintf(stderr,
  								"Sending client_encoding with %s\n",
  								setQuery);
  #endif
  						if (!PQsendQuery(conn, setQuery))
  							goto error_return;
  
  						conn->setenv_state = SETENV_STATE_CLIENT_ENCODING_WAIT;
  					}
  					else
  						conn->setenv_state = SETENV_STATE_OPTION_SEND;
  					break;
  				}
  
  			case SETENV_STATE_OPTION_SEND:
  				{
  					/*
  					 * Send SET commands for stuff directed by Environment
  					 * Options.  Note: we assume that SET commands won't start
  					 * transaction blocks, even in a 7.3 server with
  					 * autocommit off.
  					 */
  					char		setQuery[100];	/* note length limit in
  												 * sprintf below */
  
  					if (conn->next_eo->envName)
  					{
  						const char *val;
  
  						if ((val = getenv(conn->next_eo->envName)))
  						{
  							if (pg_strcasecmp(val, "default") == 0)
  								sprintf(setQuery, "SET %s = DEFAULT",
  										conn->next_eo->pgName);
  							else
  								sprintf(setQuery, "SET %s = '%.60s'",
  										conn->next_eo->pgName, val);
  #ifdef CONNECTDEBUG
  							fprintf(stderr,
  								  "Use environment variable %s to send %s\n",
  									conn->next_eo->envName, setQuery);
  #endif
  							if (!PQsendQuery(conn, setQuery))
  								goto error_return;
  
  							conn->setenv_state = SETENV_STATE_OPTION_WAIT;
  						}
  						else
  							conn->next_eo++;
  					}
  					else
  					{
  						/* No more options to send, so move on to querying */
  						conn->setenv_state = SETENV_STATE_QUERY1_SEND;
  					}
  					break;
  				}
  
  			case SETENV_STATE_CLIENT_ENCODING_WAIT:
  				{
  					if (PQisBusy(conn))
  						return PGRES_POLLING_READING;
  
  					res = PQgetResult(conn);
  
  					if (res)
  					{
  						if (PQresultStatus(res) != PGRES_COMMAND_OK)
  						{
  							PQclear(res);
  							goto error_return;
  						}
  						PQclear(res);
  						/* Keep reading until PQgetResult returns NULL */
  					}
  					else
  					{
  						/* Query finished, so send the next option */
  						conn->setenv_state = SETENV_STATE_OPTION_SEND;
  					}
  					break;
  				}
  
  			case SETENV_STATE_OPTION_WAIT:
  				{
  					if (PQisBusy(conn))
  						return PGRES_POLLING_READING;
  
  					res = PQgetResult(conn);
  
  					if (res)
  					{
  						if (PQresultStatus(res) != PGRES_COMMAND_OK)
  						{
  							PQclear(res);
  							goto error_return;
  						}
  						PQclear(res);
  						/* Keep reading until PQgetResult returns NULL */
  					}
  					else
  					{
  						/* Query finished, so send the next option */
  						conn->next_eo++;
  						conn->setenv_state = SETENV_STATE_OPTION_SEND;
  					}
  					break;
  				}
  
  			case SETENV_STATE_QUERY1_SEND:
  				{
  					/*
  					 * Issue query to get information we need.  Here we must
  					 * use begin/commit in case autocommit is off by default
  					 * in a 7.3 server.
  					 *
  					 * Note: version() exists in all protocol-2.0-supporting
  					 * backends.  In 7.3 it would be safer to write
  					 * pg_catalog.version(), but we can't do that without
  					 * causing problems on older versions.
  					 */
  					if (!PQsendQuery(conn, "begin; select version(); end"))
  						goto error_return;
  
  					conn->setenv_state = SETENV_STATE_QUERY1_WAIT;
  					return PGRES_POLLING_READING;
  				}
  
  			case SETENV_STATE_QUERY1_WAIT:
  				{
  					if (PQisBusy(conn))
  						return PGRES_POLLING_READING;
  
  					res = PQgetResult(conn);
  
  					if (res)
  					{
  						char	   *val;
  
  						if (PQresultStatus(res) == PGRES_COMMAND_OK)
  						{
  							/* ignore begin/commit command results */
  							PQclear(res);
  							continue;
  						}
  
  						if (PQresultStatus(res) != PGRES_TUPLES_OK ||
  							PQntuples(res) != 1)
  						{
  							PQclear(res);
  							goto error_return;
  						}
  
  						/*
  						 * Extract server version and save as if
  						 * ParameterStatus
  						 */
  						val = PQgetvalue(res, 0, 0);
  						if (val && strncmp(val, "PostgreSQL ", 11) == 0)
  						{
  							char	   *ptr;
  
  							/* strip off PostgreSQL part */
  							val += 11;
  
  							/*
  							 * strip off platform part (scribbles on result,
  							 * naughty naughty)
  							 */
  							ptr = strchr(val, ' ');
  							if (ptr)
  								*ptr = '\0';
  
  							pqSaveParameterStatus(conn, "server_version",
  												  val);
  						}
  
  						PQclear(res);
  						/* Keep reading until PQgetResult returns NULL */
  					}
  					else
  					{
  						/* Query finished, move to next */
  						conn->setenv_state = SETENV_STATE_QUERY2_SEND;
  					}
  					break;
  				}
  
  			case SETENV_STATE_QUERY2_SEND:
  				{
  					const char *query;
  
  					/*
  					 * pg_client_encoding does not exist in pre-7.2 servers.
  					 * So we need to be prepared for an error here.  Do *not*
  					 * start a transaction block, except in 7.3 servers where
  					 * we need to prevent autocommit-off from starting a
  					 * transaction anyway.
  					 */
  					if (conn->sversion >= 70300 &&
  						conn->sversion < 70400)
  						query = "begin; select pg_catalog.pg_client_encoding(); end";
  					else
  						query = "select pg_client_encoding()";
  					if (!PQsendQuery(conn, query))
  						goto error_return;
  
  					conn->setenv_state = SETENV_STATE_QUERY2_WAIT;
  					return PGRES_POLLING_READING;
  				}
  
  			case SETENV_STATE_QUERY2_WAIT:
  				{
  					if (PQisBusy(conn))
  						return PGRES_POLLING_READING;
  
  					res = PQgetResult(conn);
  
  					if (res)
  					{
  						const char *val;
  
  						if (PQresultStatus(res) == PGRES_COMMAND_OK)
  						{
  							/* ignore begin/commit command results */
  							PQclear(res);
  							continue;
  						}
  
  						if (PQresultStatus(res) == PGRES_TUPLES_OK &&
  							PQntuples(res) == 1)
  						{
  							/* Extract client encoding and save it */
  							val = PQgetvalue(res, 0, 0);
  							if (val && *val)	/* null should not happen, but */
  								pqSaveParameterStatus(conn, "client_encoding",
  													  val);
  						}
  						else
  						{
  							/*
  							 * Error: presumably function not available, so
  							 * use PGCLIENTENCODING or SQL_ASCII as the
  							 * fallback.
  							 */
  							val = getenv("PGCLIENTENCODING");
  							if (val && *val)
  								pqSaveParameterStatus(conn, "client_encoding",
  													  val);
  							else
  								pqSaveParameterStatus(conn, "client_encoding",
  													  "SQL_ASCII");
  						}
  
  						PQclear(res);
  						/* Keep reading until PQgetResult returns NULL */
  					}
  					else
  					{
  						/* Query finished, so we're done */
  						conn->setenv_state = SETENV_STATE_IDLE;
  						return PGRES_POLLING_OK;
  					}
  					break;
  				}
  
  			default:
  				printfPQExpBuffer(&conn->errorMessage,
  								  libpq_gettext("invalid state %c, "
  							   "probably indicative of memory corruption\n"),
  								  conn->setenv_state);
  				goto error_return;
  		}
  	}
  
  	/* Unreachable */
  
  error_return:
  	conn->setenv_state = SETENV_STATE_IDLE;
  	return PGRES_POLLING_FAILED;
  }
  
  
  /*
   * parseInput: if appropriate, parse input data from backend
   * until input is exhausted or a stopping state is reached.
   * Note that this function will NOT attempt to read more data from the backend.
   */
  void
  pqParseInput2(PGconn *conn)
  {
  	char		id;
  
  	/*
  	 * Loop to parse successive complete messages available in the buffer.
  	 */
  	for (;;)
  	{
  		/*
  		 * Quit if in COPY_OUT state: we expect raw data from the server until
  		 * PQendcopy is called.  Don't try to parse it according to the normal
  		 * protocol.  (This is bogus.  The data lines ought to be part of the
  		 * protocol and have identifying leading characters.)
  		 */
  		if (conn->asyncStatus == PGASYNC_COPY_OUT)
  			return;
  
  		/*
  		 * OK to try to read a message type code.
  		 */
  		conn->inCursor = conn->inStart;
  		if (pqGetc(&id, conn))
  			return;
  
  		/*
  		 * NOTIFY and NOTICE messages can happen in any state besides COPY
  		 * OUT; always process them right away.
  		 *
  		 * Most other messages should only be processed while in BUSY state.
  		 * (In particular, in READY state we hold off further parsing until
  		 * the application collects the current PGresult.)
  		 *
  		 * However, if the state is IDLE then we got trouble; we need to deal
  		 * with the unexpected message somehow.
  		 */
  		if (id == 'A')
  		{
  			if (getNotify(conn))
  				return;
  		}
  		else if (id == 'N')
  		{
  			if (pqGetErrorNotice2(conn, false))
  				return;
  		}
  		else if (conn->asyncStatus != PGASYNC_BUSY)
  		{
  			/* If not IDLE state, just wait ... */
  			if (conn->asyncStatus != PGASYNC_IDLE)
  				return;
  
  			/*
  			 * Unexpected message in IDLE state; need to recover somehow.
  			 * ERROR messages are displayed using the notice processor;
  			 * anything else is just dropped on the floor after displaying a
  			 * suitable warning notice.  (An ERROR is very possibly the
  			 * backend telling us why it is about to close the connection, so
  			 * we don't want to just discard it...)
  			 */
  			if (id == 'E')
  			{
  				if (pqGetErrorNotice2(conn, false /* treat as notice */ ))
  					return;
  			}
  			else
  			{
  				pqInternalNotice(&conn->noticeHooks,
  						"message type 0x%02x arrived from server while idle",
  								 id);
  				/* Discard the unexpected message; good idea?? */
  				conn->inStart = conn->inEnd;
  				break;
  			}
  		}
  		else
  		{
  			/*
  			 * In BUSY state, we can process everything.
  			 */
  			switch (id)
  			{
  				case 'C':		/* command complete */
  					if (pqGets(&conn->workBuffer, conn))
  						return;
  					if (conn->result == NULL)
  					{
  						conn->result = PQmakeEmptyPGresult(conn,
  														   PGRES_COMMAND_OK);
  						if (!conn->result)
  						{
  							printfPQExpBuffer(&conn->errorMessage,
  											  libpq_gettext("out of memory"));
  							pqSaveErrorResult(conn);
  						}
  					}
  					if (conn->result)
  					{
  						strlcpy(conn->result->cmdStatus, conn->workBuffer.data,
  								CMDSTATUS_LEN);
  					}
  					checkXactStatus(conn, conn->workBuffer.data);
  					conn->asyncStatus = PGASYNC_READY;
  					break;
  				case 'E':		/* error return */
  					if (pqGetErrorNotice2(conn, true))
  						return;
  					conn->asyncStatus = PGASYNC_READY;
  					break;
  				case 'Z':		/* backend is ready for new query */
  					conn->asyncStatus = PGASYNC_IDLE;
  					break;
  				case 'I':		/* empty query */
  					/* read and throw away the closing '\0' */
  					if (pqGetc(&id, conn))
  						return;
  					if (id != '\0')
  						pqInternalNotice(&conn->noticeHooks,
  										 "unexpected character %c following empty query response (\"I\" message)",
  										 id);
  					if (conn->result == NULL)
  					{
  						conn->result = PQmakeEmptyPGresult(conn,
  														   PGRES_EMPTY_QUERY);
  						if (!conn->result)
  						{
  							printfPQExpBuffer(&conn->errorMessage,
  											  libpq_gettext("out of memory"));
  							pqSaveErrorResult(conn);
  						}
  					}
  					conn->asyncStatus = PGASYNC_READY;
  					break;
  				case 'K':		/* secret key data from the backend */
  
  					/*
  					 * This is expected only during backend startup, but it's
  					 * just as easy to handle it as part of the main loop.
  					 * Save the data and continue processing.
  					 */
  					if (pqGetInt(&(conn->be_pid), 4, conn))
  						return;
  					if (pqGetInt(&(conn->be_key), 4, conn))
  						return;
  					break;
  				case 'P':		/* synchronous (normal) portal */
  					if (pqGets(&conn->workBuffer, conn))
  						return;
  					/* We pretty much ignore this message type... */
  					break;
  				case 'T':		/* row descriptions (start of query results) */
  					if (conn->result == NULL)
  					{
  						/* First 'T' in a query sequence */
  						if (getRowDescriptions(conn))
  							return;
  						/* getRowDescriptions() moves inStart itself */
  						continue;
  					}
  					else
  					{
  						/*
  						 * A new 'T' message is treated as the start of
  						 * another PGresult.  (It is not clear that this is
  						 * really possible with the current backend.) We stop
  						 * parsing until the application accepts the current
  						 * result.
  						 */
  						conn->asyncStatus = PGASYNC_READY;
  						return;
  					}
  					break;
  				case 'D':		/* ASCII data tuple */
  					if (conn->result != NULL)
  					{
  						/* Read another tuple of a normal query response */
  						if (getAnotherTuple(conn, FALSE))
  							return;
  						/* getAnotherTuple() moves inStart itself */
  						continue;
  					}
  					else
  					{
  						pqInternalNotice(&conn->noticeHooks,
  										 "server sent data (\"D\" message) without prior row description (\"T\" message)");
  						/* Discard the unexpected message; good idea?? */
  						conn->inStart = conn->inEnd;
  						return;
  					}
  					break;
  				case 'B':		/* Binary data tuple */
  					if (conn->result != NULL)
  					{
  						/* Read another tuple of a normal query response */
  						if (getAnotherTuple(conn, TRUE))
  							return;
  						/* getAnotherTuple() moves inStart itself */
  						continue;
  					}
  					else
  					{
  						pqInternalNotice(&conn->noticeHooks,
  										 "server sent binary data (\"B\" message) without prior row description (\"T\" message)");
  						/* Discard the unexpected message; good idea?? */
  						conn->inStart = conn->inEnd;
  						return;
  					}
  					break;
  				case 'G':		/* Start Copy In */
  					conn->asyncStatus = PGASYNC_COPY_IN;
  					break;
  				case 'H':		/* Start Copy Out */
  					conn->asyncStatus = PGASYNC_COPY_OUT;
  					break;
  
  					/*
  					 * Don't need to process CopyBothResponse here because it
  					 * never arrives from the server during protocol 2.0.
  					 */
  				default:
  					printfPQExpBuffer(&conn->errorMessage,
  									  libpq_gettext(
  													"unexpected response from server; first received character was \"%c\"\n"),
  									  id);
  					/* build an error result holding the error message */
  					pqSaveErrorResult(conn);
  					/* Discard the unexpected message; good idea?? */
  					conn->inStart = conn->inEnd;
  					conn->asyncStatus = PGASYNC_READY;
  					return;
  			}					/* switch on protocol character */
  		}
  		/* Successfully consumed this message */
  		conn->inStart = conn->inCursor;
  	}
  }
  
  /*
   * parseInput subroutine to read a 'T' (row descriptions) message.
   * We build a PGresult structure containing the attribute data.
   * Returns: 0 if completed message, EOF if error or not enough data
   * received yet.
   *
   * Note that if we run out of data, we have to suspend and reprocess
   * the message after more data is received.  Otherwise, conn->inStart
   * must get advanced past the processed data.
   */
  static int
  getRowDescriptions(PGconn *conn)
  {
  	PGresult   *result;
  	int			nfields;
  	const char *errmsg;
  	int			i;
  
  	result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK);
  	if (!result)
  	{
  		errmsg = NULL;			/* means "out of memory", see below */
  		goto advance_and_error;
  	}
  
  	/* parseInput already read the 'T' label. */
  	/* the next two bytes are the number of fields	*/
  	if (pqGetInt(&(result->numAttributes), 2, conn))
  		goto EOFexit;
  	nfields = result->numAttributes;
  
  	/* allocate space for the attribute descriptors */
  	if (nfields > 0)
  	{
  		result->attDescs = (PGresAttDesc *)
  			pqResultAlloc(result, nfields * sizeof(PGresAttDesc), TRUE);
  		if (!result->attDescs)
  		{
  			errmsg = NULL;		/* means "out of memory", see below */
  			goto advance_and_error;
  		}
  		MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
  	}
  
  	/* get type info */
  	for (i = 0; i < nfields; i++)
  	{
  		int			typid;
  		int			typlen;
  		int			atttypmod;
  
  		if (pqGets(&conn->workBuffer, conn) ||
  			pqGetInt(&typid, 4, conn) ||
  			pqGetInt(&typlen, 2, conn) ||
  			pqGetInt(&atttypmod, 4, conn))
  			goto EOFexit;
  
  		/*
  		 * Since pqGetInt treats 2-byte integers as unsigned, we need to
  		 * coerce the result to signed form.
  		 */
  		typlen = (int) ((int16) typlen);
  
  		result->attDescs[i].name = pqResultStrdup(result,
  												  conn->workBuffer.data);
  		if (!result->attDescs[i].name)
  		{
  			errmsg = NULL;		/* means "out of memory", see below */
  			goto advance_and_error;
  		}
  		result->attDescs[i].tableid = 0;
  		result->attDescs[i].columnid = 0;
  		result->attDescs[i].format = 0;
  		result->attDescs[i].typid = typid;
  		result->attDescs[i].typlen = typlen;
  		result->attDescs[i].atttypmod = atttypmod;
  	}
  
  	/* Success! */
  	conn->result = result;
  
  	/* Advance inStart to show that the "T" message has been processed. */
  	conn->inStart = conn->inCursor;
  
  	/*
  	 * We could perform additional setup for the new result set here, but for
  	 * now there's nothing else to do.
  	 */
  
  	/* And we're done. */
  	return 0;
  
  advance_and_error:
  
  	/*
  	 * Discard the failed message.  Unfortunately we don't know for sure where
  	 * the end is, so just throw away everything in the input buffer. This is
  	 * not very desirable but it's the best we can do in protocol v2.
  	 */
  	conn->inStart = conn->inEnd;
  
  	/*
  	 * Replace partially constructed result with an error result. First
  	 * discard the old result to try to win back some memory.
  	 */
  	pqClearAsyncResult(conn);
  
  	/*
  	 * If preceding code didn't provide an error message, assume "out of
  	 * memory" was meant.  The advantage of having this special case is that
  	 * freeing the old result first greatly improves the odds that gettext()
  	 * will succeed in providing a translation.
  	 */
  	if (!errmsg)
  		errmsg = libpq_gettext("out of memory for query result");
  
  	printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
  
  	/*
  	 * XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
  	 * do to recover...
  	 */
  	conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
  	conn->asyncStatus = PGASYNC_READY;
  
  EOFexit:
  	if (result && result != conn->result)
  		PQclear(result);
  	return EOF;
  }
  
  /*
   * parseInput subroutine to read a 'B' or 'D' (row data) message.
   * We fill rowbuf with column pointers and then call the row processor.
   * Returns: 0 if completed message, EOF if error or not enough data
   * received yet.
   *
   * Note that if we run out of data, we have to suspend and reprocess
   * the message after more data is received.  Otherwise, conn->inStart
   * must get advanced past the processed data.
   */
  static int
  getAnotherTuple(PGconn *conn, bool binary)
  {
  	PGresult   *result = conn->result;
  	int			nfields = result->numAttributes;
  	const char *errmsg;
  	PGdataValue *rowbuf;
  
  	/* the backend sends us a bitmap of which attributes are null */
  	char		std_bitmap[64]; /* used unless it doesn't fit */
  	char	   *bitmap = std_bitmap;
  	int			i;
  	size_t		nbytes;			/* the number of bytes in bitmap  */
  	char		bmap;			/* One byte of the bitmap */
  	int			bitmap_index;	/* Its index */
  	int			bitcnt;			/* number of bits examined in current byte */
  	int			vlen;			/* length of the current field value */
  
  	/* Resize row buffer if needed */
  	rowbuf = conn->rowBuf;
  	if (nfields > conn->rowBufLen)
  	{
  		rowbuf = (PGdataValue *) realloc(rowbuf,
  										 nfields * sizeof(PGdataValue));
  		if (!rowbuf)
  		{
  			errmsg = NULL;		/* means "out of memory", see below */
  			goto advance_and_error;
  		}
  		conn->rowBuf = rowbuf;
  		conn->rowBufLen = nfields;
  	}
  
  	/* Save format specifier */
  	result->binary = binary;
  
  	/*
  	 * If it's binary, fix the column format indicators.  We assume the
  	 * backend will consistently send either B or D, not a mix.
  	 */
  	if (binary)
  	{
  		for (i = 0; i < nfields; i++)
  			result->attDescs[i].format = 1;
  	}
  
  	/* Get the null-value bitmap */
  	nbytes = (nfields + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
  	/* malloc() only for unusually large field counts... */
  	if (nbytes > sizeof(std_bitmap))
  	{
  		bitmap = (char *) malloc(nbytes);
  		if (!bitmap)
  		{
  			errmsg = NULL;		/* means "out of memory", see below */
  			goto advance_and_error;
  		}
  	}
  
  	if (pqGetnchar(bitmap, nbytes, conn))
  		goto EOFexit;
  
  	/* Scan the fields */
  	bitmap_index = 0;
  	bmap = bitmap[bitmap_index];
  	bitcnt = 0;
  
  	for (i = 0; i < nfields; i++)
  	{
  		/* get the value length */
  		if (!(bmap & 0200))
  			vlen = NULL_LEN;
  		else if (pqGetInt(&vlen, 4, conn))
  			goto EOFexit;
  		else
  		{
  			if (!binary)
  				vlen = vlen - 4;
  			if (vlen < 0)
  				vlen = 0;
  		}
  		rowbuf[i].len = vlen;
  
  		/*
  		 * rowbuf[i].value always points to the next address in the data
  		 * buffer even if the value is NULL.  This allows row processors to
  		 * estimate data sizes more easily.
  		 */
  		rowbuf[i].value = conn->inBuffer + conn->inCursor;
  
  		/* Skip over the data value */
  		if (vlen > 0)
  		{
  			if (pqSkipnchar(vlen, conn))
  				goto EOFexit;
  		}
  
  		/* advance the bitmap stuff */
  		bitcnt++;
  		if (bitcnt == BITS_PER_BYTE)
  		{
  			bitmap_index++;
  			bmap = bitmap[bitmap_index];
  			bitcnt = 0;
  		}
  		else
  			bmap <<= 1;
  	}
  
  	/* Release bitmap now if we allocated it */
  	if (bitmap != std_bitmap)
  		free(bitmap);
  	bitmap = NULL;
  
  	/* Advance inStart to show that the "D" message has been processed. */
  	conn->inStart = conn->inCursor;
  
  	/* Process the collected row */
  	errmsg = NULL;
  	if (pqRowProcessor(conn, &errmsg))
  		return 0;				/* normal, successful exit */
  
  	goto set_error_result;		/* pqRowProcessor failed, report it */
  
  advance_and_error:
  
  	/*
  	 * Discard the failed message.  Unfortunately we don't know for sure where
  	 * the end is, so just throw away everything in the input buffer. This is
  	 * not very desirable but it's the best we can do in protocol v2.
  	 */
  	conn->inStart = conn->inEnd;
  
  set_error_result:
  
  	/*
  	 * Replace partially constructed result with an error result. First
  	 * discard the old result to try to win back some memory.
  	 */
  	pqClearAsyncResult(conn);
  
  	/*
  	 * If preceding code didn't provide an error message, assume "out of
  	 * memory" was meant.  The advantage of having this special case is that
  	 * freeing the old result first greatly improves the odds that gettext()
  	 * will succeed in providing a translation.
  	 */
  	if (!errmsg)
  		errmsg = libpq_gettext("out of memory for query result");
  
  	printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
  
  	/*
  	 * XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
  	 * do to recover...
  	 */
  	conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
  	conn->asyncStatus = PGASYNC_READY;
  
  EOFexit:
  	if (bitmap != NULL && bitmap != std_bitmap)
  		free(bitmap);
  	return EOF;
  }
  
  
  /*
   * Attempt to read an Error or Notice response message.
   * This is possible in several places, so we break it out as a subroutine.
   * Entry: 'E' or 'N' message type has already been consumed.
   * Exit: returns 0 if successfully consumed message.
   *		 returns EOF if not enough data.
   */
  static int
  pqGetErrorNotice2(PGconn *conn, bool isError)
  {
  	PGresult   *res = NULL;
  	PQExpBufferData workBuf;
  	char	   *startp;
  	char	   *splitp;
  
  	/*
  	 * If this is an error message, pre-emptively clear any incomplete query
  	 * result we may have.  We'd just throw it away below anyway, and
  	 * releasing it before collecting the error might avoid out-of-memory.
  	 */
  	if (isError)
  		pqClearAsyncResult(conn);
  
  	/*
  	 * Since the message might be pretty long, we create a temporary
  	 * PQExpBuffer rather than using conn->workBuffer.  workBuffer is intended
  	 * for stuff that is expected to be short.
  	 */
  	initPQExpBuffer(&workBuf);
  	if (pqGets(&workBuf, conn))
  		goto failure;
  
  	/*
  	 * Make a PGresult to hold the message.  We temporarily lie about the
  	 * result status, so that PQmakeEmptyPGresult doesn't uselessly copy
  	 * conn->errorMessage.
  	 *
  	 * NB: This allocation can fail, if you run out of memory. The rest of the
  	 * function handles that gracefully, and we still try to set the error
  	 * message as the connection's error message.
  	 */
  	res = PQmakeEmptyPGresult(conn, PGRES_EMPTY_QUERY);
  	if (res)
  	{
  		res->resultStatus = isError ? PGRES_FATAL_ERROR : PGRES_NONFATAL_ERROR;
  		res->errMsg = pqResultStrdup(res, workBuf.data);
  	}
  
  	/*
  	 * Break the message into fields.  We can't do very much here, but we can
  	 * split the severity code off, and remove trailing newlines. Also, we use
  	 * the heuristic that the primary message extends only to the first
  	 * newline --- anything after that is detail message.  (In some cases it'd
  	 * be better classed as hint, but we can hardly be expected to guess that
  	 * here.)
  	 */
  	while (workBuf.len > 0 && workBuf.data[workBuf.len - 1] == '\n')
  		workBuf.data[--workBuf.len] = '\0';
  	splitp = strstr(workBuf.data, ":  ");
  	if (splitp)
  	{
  		/* what comes before the colon is severity */
  		*splitp = '\0';
  		pqSaveMessageField(res, PG_DIAG_SEVERITY, workBuf.data);
  		startp = splitp + 3;
  	}
  	else
  	{
  		/* can't find a colon?  oh well... */
  		startp = workBuf.data;
  	}
  	splitp = strchr(startp, '\n');
  	if (splitp)
  	{
  		/* what comes before the newline is primary message */
  		*splitp++ = '\0';
  		pqSaveMessageField(res, PG_DIAG_MESSAGE_PRIMARY, startp);
  		/* the rest is detail; strip any leading whitespace */
  		while (*splitp && isspace((unsigned char) *splitp))
  			splitp++;
  		pqSaveMessageField(res, PG_DIAG_MESSAGE_DETAIL, splitp);
  	}
  	else
  	{
  		/* single-line message, so all primary */
  		pqSaveMessageField(res, PG_DIAG_MESSAGE_PRIMARY, startp);
  	}
  
  	/*
  	 * Either save error as current async result, or just emit the notice.
  	 * Also, if it's an error and we were in a transaction block, assume the
  	 * server has now gone to error-in-transaction state.
  	 */
  	if (isError)
  	{
  		pqClearAsyncResult(conn);	/* redundant, but be safe */
  		conn->result = res;
  		resetPQExpBuffer(&conn->errorMessage);
  		if (res && !PQExpBufferDataBroken(workBuf) && res->errMsg)
  			appendPQExpBufferStr(&conn->errorMessage, res->errMsg);
  		else
  			printfPQExpBuffer(&conn->errorMessage,
  							  libpq_gettext("out of memory"));
  		if (conn->xactStatus == PQTRANS_INTRANS)
  			conn->xactStatus = PQTRANS_INERROR;
  	}
  	else
  	{
  		if (res)
  		{
  			if (res->noticeHooks.noticeRec != NULL)
  				(*res->noticeHooks.noticeRec) (res->noticeHooks.noticeRecArg, res);
  			PQclear(res);
  		}
  	}
  
  	termPQExpBuffer(&workBuf);
  	return 0;
  
  failure:
  	if (res)
  		PQclear(res);
  	termPQExpBuffer(&workBuf);
  	return EOF;
  }
  
  /*
   * checkXactStatus - attempt to track transaction-block status of server
   *
   * This is called each time we receive a command-complete message.  By
   * watching for messages from BEGIN/COMMIT/ROLLBACK commands, we can do
   * a passable job of tracking the server's xact status.  BUT: this does
   * not work at all on 7.3 servers with AUTOCOMMIT OFF.  (Man, was that
   * feature ever a mistake.)  Caveat user.
   *
   * The tags known here are all those used as far back as 7.0; is it worth
   * adding those from even-older servers?
   */
  static void
  checkXactStatus(PGconn *conn, const char *cmdTag)
  {
  	if (strcmp(cmdTag, "BEGIN") == 0)
  		conn->xactStatus = PQTRANS_INTRANS;
  	else if (strcmp(cmdTag, "COMMIT") == 0)
  		conn->xactStatus = PQTRANS_IDLE;
  	else if (strcmp(cmdTag, "ROLLBACK") == 0)
  		conn->xactStatus = PQTRANS_IDLE;
  	else if (strcmp(cmdTag, "START TRANSACTION") == 0)	/* 7.3 only */
  		conn->xactStatus = PQTRANS_INTRANS;
  
  	/*
  	 * Normally we get into INERROR state by detecting an Error message.
  	 * However, if we see one of these tags then we know for sure the server
  	 * is in abort state ...
  	 */
  	else if (strcmp(cmdTag, "*ABORT STATE*") == 0)		/* pre-7.3 only */
  		conn->xactStatus = PQTRANS_INERROR;
  }
  
  /*
   * Attempt to read a Notify response message.
   * This is possible in several places, so we break it out as a subroutine.
   * Entry: 'A' message type and length have already been consumed.
   * Exit: returns 0 if successfully consumed Notify message.
   *		 returns EOF if not enough data.
   */
  static int
  getNotify(PGconn *conn)
  {
  	int			be_pid;
  	int			nmlen;
  	PGnotify   *newNotify;
  
  	if (pqGetInt(&be_pid, 4, conn))
  		return EOF;
  	if (pqGets(&conn->workBuffer, conn))
  		return EOF;
  
  	/*
  	 * Store the relation name right after the PQnotify structure so it can
  	 * all be freed at once.  We don't use NAMEDATALEN because we don't want
  	 * to tie this interface to a specific server name length.
  	 */
  	nmlen = strlen(conn->workBuffer.data);
  	newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + 1);
  	if (newNotify)
  	{
  		newNotify->relname = (char *) newNotify + sizeof(PGnotify);
  		strcpy(newNotify->relname, conn->workBuffer.data);
  		/* fake up an empty-string extra field */
  		newNotify->extra = newNotify->relname + nmlen;
  		newNotify->be_pid = be_pid;
  		newNotify->next = NULL;
  		if (conn->notifyTail)
  			conn->notifyTail->next = newNotify;
  		else
  			conn->notifyHead = newNotify;
  		conn->notifyTail = newNotify;
  	}
  
  	return 0;
  }
  
  
  /*
   * PQgetCopyData - read a row of data from the backend during COPY OUT
   *
   * If successful, sets *buffer to point to a malloc'd row of data, and
   * returns row length (always > 0) as result.
   * Returns 0 if no row available yet (only possible if async is true),
   * -1 if end of copy (consult PQgetResult), or -2 if error (consult
   * PQerrorMessage).
   */
  int
  pqGetCopyData2(PGconn *conn, char **buffer, int async)
  {
  	bool		found;
  	int			msgLength;
  
  	for (;;)
  	{
  		/*
  		 * Do we have a complete line of data?
  		 */
  		conn->inCursor = conn->inStart;
  		found = false;
  		while (conn->inCursor < conn->inEnd)
  		{
  			char		c = conn->inBuffer[conn->inCursor++];
  
  			if (c == '\n')
  			{
  				found = true;
  				break;
  			}
  		}
  		if (!found)
  			goto nodata;
  		msgLength = conn->inCursor - conn->inStart;
  
  		/*
  		 * If it's the end-of-data marker, consume it, exit COPY_OUT mode, and
  		 * let caller read status with PQgetResult().
  		 */
  		if (msgLength == 3 &&
  			strncmp(&conn->inBuffer[conn->inStart], "\\.\n", 3) == 0)
  		{
  			conn->inStart = conn->inCursor;
  			conn->asyncStatus = PGASYNC_BUSY;
  			return -1;
  		}
  
  		/*
  		 * Pass the line back to the caller.
  		 */
  		*buffer = (char *) malloc(msgLength + 1);
  		if (*buffer == NULL)
  		{
  			printfPQExpBuffer(&conn->errorMessage,
  							  libpq_gettext("out of memory\n"));
  			return -2;
  		}
  		memcpy(*buffer, &conn->inBuffer[conn->inStart], msgLength);
  		(*buffer)[msgLength] = '\0';	/* Add terminating null */
  
  		/* Mark message consumed */
  		conn->inStart = conn->inCursor;
  
  		return msgLength;
  
  nodata:
  		/* Don't block if async read requested */
  		if (async)
  			return 0;
  		/* Need to load more data */
  		if (pqWait(TRUE, FALSE, conn) ||
  			pqReadData(conn) < 0)
  			return -2;
  	}
  }
  
  
  /*
   * PQgetline - gets a newline-terminated string from the backend.
   *
   * See fe-exec.c for documentation.
   */
  int
  pqGetline2(PGconn *conn, char *s, int maxlen)
  {
  	int			result = 1;		/* return value if buffer overflows */
  
  	if (conn->sock == PGINVALID_SOCKET ||
  		conn->asyncStatus != PGASYNC_COPY_OUT)
  	{
  		*s = '\0';
  		return EOF;
  	}
  
  	/*
  	 * Since this is a purely synchronous routine, we don't bother to maintain
  	 * conn->inCursor; there is no need to back up.
  	 */
  	while (maxlen > 1)
  	{
  		if (conn->inStart < conn->inEnd)
  		{
  			char		c = conn->inBuffer[conn->inStart++];
  
  			if (c == '\n')
  			{
  				result = 0;		/* success exit */
  				break;
  			}
  			*s++ = c;
  			maxlen--;
  		}
  		else
  		{
  			/* need to load more data */
  			if (pqWait(TRUE, FALSE, conn) ||
  				pqReadData(conn) < 0)
  			{
  				result = EOF;
  				break;
  			}
  		}
  	}
  	*s = '\0';
  
  	return result;
  }
  
  /*
   * PQgetlineAsync - gets a COPY data row without blocking.
   *
   * See fe-exec.c for documentation.
   */
  int
  pqGetlineAsync2(PGconn *conn, char *buffer, int bufsize)
  {
  	int			avail;
  
  	if (conn->asyncStatus != PGASYNC_COPY_OUT)
  		return -1;				/* we are not doing a copy... */
  
  	/*
  	 * Move data from libpq's buffer to the caller's. We want to accept data
  	 * only in units of whole lines, not partial lines.  This ensures that we
  	 * can recognize the terminator line "\\.\n".  (Otherwise, if it happened
  	 * to cross a packet/buffer boundary, we might hand the first one or two
  	 * characters off to the caller, which we shouldn't.)
  	 */
  
  	conn->inCursor = conn->inStart;
  
  	avail = bufsize;
  	while (avail > 0 && conn->inCursor < conn->inEnd)
  	{
  		char		c = conn->inBuffer[conn->inCursor++];
  
  		*buffer++ = c;
  		--avail;
  		if (c == '\n')
  		{
  			/* Got a complete line; mark the data removed from libpq */
  			conn->inStart = conn->inCursor;
  			/* Is it the endmarker line? */
  			if (bufsize - avail == 3 && buffer[-3] == '\\' && buffer[-2] == '.')
  				return -1;
  			/* No, return the data line to the caller */
  			return bufsize - avail;
  		}
  	}
  
  	/*
  	 * We don't have a complete line. We'd prefer to leave it in libpq's
  	 * buffer until the rest arrives, but there is a special case: what if the
  	 * line is longer than the buffer the caller is offering us?  In that case
  	 * we'd better hand over a partial line, else we'd get into an infinite
  	 * loop. Do this in a way that ensures we can't misrecognize a terminator
  	 * line later: leave last 3 characters in libpq buffer.
  	 */
  	if (avail == 0 && bufsize > 3)
  	{
  		conn->inStart = conn->inCursor - 3;
  		return bufsize - 3;
  	}
  	return 0;
  }
  
  /*
   * PQendcopy
   *
   * See fe-exec.c for documentation.
   */
  int
  pqEndcopy2(PGconn *conn)
  {
  	PGresult   *result;
  
  	if (conn->asyncStatus != PGASYNC_COPY_IN &&
  		conn->asyncStatus != PGASYNC_COPY_OUT)
  	{
  		printfPQExpBuffer(&conn->errorMessage,
  						  libpq_gettext("no COPY in progress\n"));
  		return 1;
  	}
  
  	/*
  	 * make sure no data is waiting to be sent, abort if we are non-blocking
  	 * and the flush fails
  	 */
  	if (pqFlush(conn) && pqIsnonblocking(conn))
  		return 1;
  
  	/* non blocking connections may have to abort at this point. */
  	if (pqIsnonblocking(conn) && PQisBusy(conn))
  		return 1;
  
  	/* Return to active duty */
  	conn->asyncStatus = PGASYNC_BUSY;
  	resetPQExpBuffer(&conn->errorMessage);
  
  	/* Wait for the completion response */
  	result = PQgetResult(conn);
  
  	/* Expecting a successful result */
  	if (result && result->resultStatus == PGRES_COMMAND_OK)
  	{
  		PQclear(result);
  		return 0;
  	}
  
  	/*
  	 * Trouble. For backwards-compatibility reasons, we issue the error
  	 * message as if it were a notice (would be nice to get rid of this
  	 * silliness, but too many apps probably don't handle errors from
  	 * PQendcopy reasonably).  Note that the app can still obtain the error
  	 * status from the PGconn object.
  	 */
  	if (conn->errorMessage.len > 0)
  	{
  		/* We have to strip the trailing newline ... pain in neck... */
  		char		svLast = conn->errorMessage.data[conn->errorMessage.len - 1];
  
  		if (svLast == '\n')
  			conn->errorMessage.data[conn->errorMessage.len - 1] = '\0';
  		pqInternalNotice(&conn->noticeHooks, "%s", conn->errorMessage.data);
  		conn->errorMessage.data[conn->errorMessage.len - 1] = svLast;
  	}
  
  	PQclear(result);
  
  	/*
  	 * The worst case is that we've lost sync with the backend entirely due to
  	 * application screwup of the copy in/out protocol. To recover, reset the
  	 * connection (talk about using a sledgehammer...)
  	 */
  	pqInternalNotice(&conn->noticeHooks,
  				   "lost synchronization with server, resetting connection");
  
  	/*
  	 * Users doing non-blocking connections need to handle the reset
  	 * themselves, they'll need to check the connection status if we return an
  	 * error.
  	 */
  	if (pqIsnonblocking(conn))
  		PQresetStart(conn);
  	else
  		PQreset(conn);
  
  	return 1;
  }
  
  
  /*
   * PQfn - Send a function call to the POSTGRES backend.
   *
   * See fe-exec.c for documentation.
   */
  PGresult *
  pqFunctionCall2(PGconn *conn, Oid fnid,
  				int *result_buf, int *actual_result_len,
  				int result_is_int,
  				const PQArgBlock *args, int nargs)
  {
  	bool		needInput = false;
  	ExecStatusType status = PGRES_FATAL_ERROR;
  	char		id;
  	int			i;
  
  	/* PQfn already validated connection state */
  
  	if (pqPutMsgStart('F', false, conn) < 0 ||	/* function call msg */
  		pqPuts(" ", conn) < 0 ||	/* dummy string */
  		pqPutInt(fnid, 4, conn) != 0 || /* function id */
  		pqPutInt(nargs, 4, conn) != 0)	/* # of args */
  	{
  		pqHandleSendFailure(conn);
  		return NULL;
  	}
  
  	for (i = 0; i < nargs; ++i)
  	{							/* len.int4 + contents	   */
  		if (pqPutInt(args[i].len, 4, conn))
  		{
  			pqHandleSendFailure(conn);
  			return NULL;
  		}
  
  		if (args[i].isint)
  		{
  			if (pqPutInt(args[i].u.integer, 4, conn))
  			{
  				pqHandleSendFailure(conn);
  				return NULL;
  			}
  		}
  		else
  		{
  			if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
  			{
  				pqHandleSendFailure(conn);
  				return NULL;
  			}
  		}
  	}
  
  	if (pqPutMsgEnd(conn) < 0 ||
  		pqFlush(conn))
  	{
  		pqHandleSendFailure(conn);
  		return NULL;
  	}
  
  	for (;;)
  	{
  		if (needInput)
  		{
  			/* Wait for some data to arrive (or for the channel to close) */
  			if (pqWait(TRUE, FALSE, conn) ||
  				pqReadData(conn) < 0)
  				break;
  		}
  
  		/*
  		 * Scan the message. If we run out of data, loop around to try again.
  		 */
  		conn->inCursor = conn->inStart;
  		needInput = true;
  
  		if (pqGetc(&id, conn))
  			continue;
  
  		/*
  		 * We should see V or E response to the command, but might get N
  		 * and/or A notices first. We also need to swallow the final Z before
  		 * returning.
  		 */
  		switch (id)
  		{
  			case 'V':			/* function result */
  				if (pqGetc(&id, conn))
  					continue;
  				if (id == 'G')
  				{
  					/* function returned nonempty value */
  					if (pqGetInt(actual_result_len, 4, conn))
  						continue;
  					if (result_is_int)
  					{
  						if (pqGetInt(result_buf, 4, conn))
  							continue;
  					}
  					else
  					{
  						if (pqGetnchar((char *) result_buf,
  									   *actual_result_len,
  									   conn))
  							continue;
  					}
  					if (pqGetc(&id, conn))		/* get the last '0' */
  						continue;
  				}
  				if (id == '0')
  				{
  					/* correctly finished function result message */
  					status = PGRES_COMMAND_OK;
  				}
  				else
  				{
  					/* The backend violates the protocol. */
  					printfPQExpBuffer(&conn->errorMessage,
  								  libpq_gettext("protocol error: id=0x%x\n"),
  									  id);
  					pqSaveErrorResult(conn);
  					conn->inStart = conn->inCursor;
  					return pqPrepareAsyncResult(conn);
  				}
  				break;
  			case 'E':			/* error return */
  				if (pqGetErrorNotice2(conn, true))
  					continue;
  				status = PGRES_FATAL_ERROR;
  				break;
  			case 'A':			/* notify message */
  				/* handle notify and go back to processing return values */
  				if (getNotify(conn))
  					continue;
  				break;
  			case 'N':			/* notice */
  				/* handle notice and go back to processing return values */
  				if (pqGetErrorNotice2(conn, false))
  					continue;
  				break;
  			case 'Z':			/* backend is ready for new query */
  				/* consume the message and exit */
  				conn->inStart = conn->inCursor;
  				/* if we saved a result object (probably an error), use it */
  				if (conn->result)
  					return pqPrepareAsyncResult(conn);
  				return PQmakeEmptyPGresult(conn, status);
  			default:
  				/* The backend violates the protocol. */
  				printfPQExpBuffer(&conn->errorMessage,
  								  libpq_gettext("protocol error: id=0x%x\n"),
  								  id);
  				pqSaveErrorResult(conn);
  				conn->inStart = conn->inCursor;
  				return pqPrepareAsyncResult(conn);
  		}
  		/* Completed this message, keep going */
  		conn->inStart = conn->inCursor;
  		needInput = false;
  	}
  
  	/*
  	 * We fall out of the loop only upon failing to read data.
  	 * conn->errorMessage has been set by pqWait or pqReadData. We want to
  	 * append it to any already-received error message.
  	 */
  	pqSaveErrorResult(conn);
  	return pqPrepareAsyncResult(conn);
  }
  
  
  /*
   * Construct startup packet
   *
   * Returns a malloc'd packet buffer, or NULL if out of memory
   */
  char *
  pqBuildStartupPacket2(PGconn *conn, int *packetlen,
  					  const PQEnvironmentOption *options)
  {
  	StartupPacket *startpacket;
  
  	*packetlen = sizeof(StartupPacket);
  	startpacket = (StartupPacket *) malloc(sizeof(StartupPacket));
  	if (!startpacket)
  		return NULL;
  
  	MemSet(startpacket, 0, sizeof(StartupPacket));
  
  	startpacket->protoVersion = htonl(conn->pversion);
  
  	/* strncpy is safe here: postmaster will handle full fields correctly */
  	strncpy(startpacket->user, conn->pguser, SM_USER);
  	strncpy(startpacket->database, conn->dbName, SM_DATABASE);
  	strncpy(startpacket->tty, conn->pgtty, SM_TTY);
  
  	if (conn->pgoptions)
  		strncpy(startpacket->options, conn->pgoptions, SM_OPTIONS);
  
  	return (char *) startpacket;
  }
  