Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2254 insertions, 0 deletions

diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
new file mode 100644
index 0000000..c33f904
--- /dev/null
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -0,0 +1,2254 @@
+/*-------------------------------------------------------------------------
+ *
+ * fe-protocol3.c
+ *	  functions that are specific to frontend/backend protocol version 3
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/interfaces/libpq/fe-protocol3.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#include <ctype.h>
+#include <fcntl.h>
+
+#ifdef WIN32
+#include "win32.h"
+#else
+#include <unistd.h>
+#ifdef HAVE_NETINET_TCP_H
+#include <netinet/tcp.h>
+#endif
+#endif
+
+#include "libpq-fe.h"
+#include "libpq-int.h"
+#include "mb/pg_wchar.h"
+#include "port/pg_bswap.h"
+
+/*
+ * This macro lists the backend message types that could be "long" (more
+ * than a couple of kilobytes).
+ */
+#define VALID_LONG_MESSAGE_TYPE(id) \
+	((id) == 'T' || (id) == 'D' || (id) == 'd' || (id) == 'V' || \
+	 (id) == 'E' || (id) == 'N' || (id) == 'A')
+
+
+static void handleSyncLoss(PGconn *conn, char id, int msgLength);
+static int	getRowDescriptions(PGconn *conn, int msgLength);
+static int	getParamDescriptions(PGconn *conn, int msgLength);
+static int	getAnotherTuple(PGconn *conn, int msgLength);
+static int	getParameterStatus(PGconn *conn);
+static int	getNotify(PGconn *conn);
+static int	getCopyStart(PGconn *conn, ExecStatusType copytype);
+static int	getReadyForQuery(PGconn *conn);
+static void reportErrorPosition(PQExpBuffer msg, const char *query,
+								int loc, int encoding);
+static int	build_startup_packet(const PGconn *conn, char *packet,
+								 const PQEnvironmentOption *options);
+
+
+/*
+ * 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
+pqParseInput3(PGconn *conn)
+{
+	char		id;
+	int			msgLength;
+	int			avail;
+
+	/*
+	 * Loop to parse successive complete messages available in the buffer.
+	 */
+	for (;;)
+	{
+		/*
+		 * Try to read a message.  First get the type code and length. Return
+		 * if not enough data.
+		 */
+		conn->inCursor = conn->inStart;
+		if (pqGetc(&id, conn))
+			return;
+		if (pqGetInt(&msgLength, 4, conn))
+			return;
+
+		/*
+		 * Try to validate message type/length here.  A length less than 4 is
+		 * definitely broken.  Large lengths should only be believed for a few
+		 * message types.
+		 */
+		if (msgLength < 4)
+		{
+			handleSyncLoss(conn, id, msgLength);
+			return;
+		}
+		if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
+		{
+			handleSyncLoss(conn, id, msgLength);
+			return;
+		}
+
+		/*
+		 * Can't process if message body isn't all here yet.
+		 */
+		msgLength -= 4;
+		avail = conn->inEnd - conn->inCursor;
+		if (avail < msgLength)
+		{
+			/*
+			 * Before returning, enlarge the input buffer if needed to hold
+			 * the whole message.  This is better than leaving it to
+			 * pqReadData because we can avoid multiple cycles of realloc()
+			 * when the message is large; also, we can implement a reasonable
+			 * recovery strategy if we are unable to make the buffer big
+			 * enough.
+			 */
+			if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
+									 conn))
+			{
+				/*
+				 * XXX add some better recovery code... plan is to skip over
+				 * the message using its length, then report an error. For the
+				 * moment, just treat this like loss of sync (which indeed it
+				 * might be!)
+				 */
+				handleSyncLoss(conn, id, msgLength);
+			}
+			return;
+		}
+
+		/*
+		 * NOTIFY and NOTICE messages can happen in any state; 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.
+		 *
+		 * ParameterStatus ('S') messages are a special case: in IDLE state we
+		 * must process 'em (this case could happen if a new value was adopted
+		 * from config file due to SIGHUP), but otherwise we hold off until
+		 * BUSY state.
+		 */
+		if (id == 'A')
+		{
+			if (getNotify(conn))
+				return;
+		}
+		else if (id == 'N')
+		{
+			if (pqGetErrorNotice3(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 handled using the notice processor;
+			 * ParameterStatus is handled normally; 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 (pqGetErrorNotice3(conn, false /* treat as notice */ ))
+					return;
+			}
+			else if (id == 'S')
+			{
+				if (getParameterStatus(conn))
+					return;
+			}
+			else
+			{
+				/* Any other case is unexpected and we summarily skip it */
+				pqInternalNotice(&conn->noticeHooks,
+								 "message type 0x%02x arrived from server while idle",
+								 id);
+				/* Discard the unexpected message */
+				conn->inCursor += msgLength;
+			}
+		}
+		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)
+						{
+							appendPQExpBufferStr(&conn->errorMessage,
+												 libpq_gettext("out of memory"));
+							pqSaveErrorResult(conn);
+						}
+					}
+					if (conn->result)
+						strlcpy(conn->result->cmdStatus, conn->workBuffer.data,
+								CMDSTATUS_LEN);
+					conn->asyncStatus = PGASYNC_READY;
+					break;
+				case 'E':		/* error return */
+					if (pqGetErrorNotice3(conn, true))
+						return;
+					conn->asyncStatus = PGASYNC_READY;
+					break;
+				case 'Z':		/* sync response, backend is ready for new
+								 * query */
+					if (getReadyForQuery(conn))
+						return;
+					if (conn->pipelineStatus != PQ_PIPELINE_OFF)
+					{
+						conn->result = PQmakeEmptyPGresult(conn,
+														   PGRES_PIPELINE_SYNC);
+						if (!conn->result)
+						{
+							appendPQExpBufferStr(&conn->errorMessage,
+												 libpq_gettext("out of memory"));
+							pqSaveErrorResult(conn);
+						}
+						else
+						{
+							conn->pipelineStatus = PQ_PIPELINE_ON;
+							conn->asyncStatus = PGASYNC_READY;
+						}
+					}
+					else
+					{
+						/*
+						 * In simple query protocol, advance the command queue
+						 * (see PQgetResult).
+						 */
+						if (conn->cmd_queue_head &&
+							conn->cmd_queue_head->queryclass == PGQUERY_SIMPLE)
+							pqCommandQueueAdvance(conn);
+						conn->asyncStatus = PGASYNC_IDLE;
+					}
+					break;
+				case 'I':		/* empty query */
+					if (conn->result == NULL)
+					{
+						conn->result = PQmakeEmptyPGresult(conn,
+														   PGRES_EMPTY_QUERY);
+						if (!conn->result)
+						{
+							appendPQExpBufferStr(&conn->errorMessage,
+												 libpq_gettext("out of memory"));
+							pqSaveErrorResult(conn);
+						}
+					}
+					conn->asyncStatus = PGASYNC_READY;
+					break;
+				case '1':		/* Parse Complete */
+					/* If we're doing PQprepare, we're done; else ignore */
+					if (conn->cmd_queue_head &&
+						conn->cmd_queue_head->queryclass == PGQUERY_PREPARE)
+					{
+						if (conn->result == NULL)
+						{
+							conn->result = PQmakeEmptyPGresult(conn,
+															   PGRES_COMMAND_OK);
+							if (!conn->result)
+							{
+								appendPQExpBufferStr(&conn->errorMessage,
+													 libpq_gettext("out of memory"));
+								pqSaveErrorResult(conn);
+							}
+						}
+						conn->asyncStatus = PGASYNC_READY;
+					}
+					break;
+				case '2':		/* Bind Complete */
+					/* Nothing to do for this message type */
+					break;
+				case '3':		/* Close Complete */
+					/*
+					 * If we get CloseComplete when waiting for it, consume
+					 * the queue element and keep going.  A result is not
+					 * expected from this message; it is just there so that
+					 * we know to wait for it when PQsendQuery is used in
+					 * pipeline mode, before going in IDLE state.  Failing to
+					 * do this makes us receive CloseComplete when IDLE, which
+					 * creates problems.
+					 */
+					if (conn->cmd_queue_head &&
+						conn->cmd_queue_head->queryclass == PGQUERY_CLOSE)
+					{
+						pqCommandQueueAdvance(conn);
+					}
+
+					break;
+				case 'S':		/* parameter status */
+					if (getParameterStatus(conn))
+						return;
+					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 'T':		/* Row Description */
+					if (conn->result != NULL &&
+						conn->result->resultStatus == PGRES_FATAL_ERROR)
+					{
+						/*
+						 * We've already choked for some reason.  Just discard
+						 * the data till we get to the end of the query.
+						 */
+						conn->inCursor += msgLength;
+					}
+					else if (conn->result == NULL ||
+							 (conn->cmd_queue_head &&
+							  conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE))
+					{
+						/* First 'T' in a query sequence */
+						if (getRowDescriptions(conn, msgLength))
+							return;
+					}
+					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 'n':		/* No Data */
+
+					/*
+					 * NoData indicates that we will not be seeing a
+					 * RowDescription message because the statement or portal
+					 * inquired about doesn't return rows.
+					 *
+					 * If we're doing a Describe, we have to pass something
+					 * back to the client, so set up a COMMAND_OK result,
+					 * instead of PGRES_TUPLES_OK.  Otherwise we can just
+					 * ignore this message.
+					 */
+					if (conn->cmd_queue_head &&
+						conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE)
+					{
+						if (conn->result == NULL)
+						{
+							conn->result = PQmakeEmptyPGresult(conn,
+															   PGRES_COMMAND_OK);
+							if (!conn->result)
+							{
+								appendPQExpBufferStr(&conn->errorMessage,
+													 libpq_gettext("out of memory"));
+								pqSaveErrorResult(conn);
+							}
+						}
+						conn->asyncStatus = PGASYNC_READY;
+					}
+					break;
+				case 't':		/* Parameter Description */
+					if (getParamDescriptions(conn, msgLength))
+						return;
+					break;
+				case 'D':		/* Data Row */
+					if (conn->result != NULL &&
+						conn->result->resultStatus == PGRES_TUPLES_OK)
+					{
+						/* Read another tuple of a normal query response */
+						if (getAnotherTuple(conn, msgLength))
+							return;
+					}
+					else if (conn->result != NULL &&
+							 conn->result->resultStatus == PGRES_FATAL_ERROR)
+					{
+						/*
+						 * We've already choked for some reason.  Just discard
+						 * tuples till we get to the end of the query.
+						 */
+						conn->inCursor += msgLength;
+					}
+					else
+					{
+						/* Set up to report error at end of query */
+						appendPQExpBufferStr(&conn->errorMessage,
+											 libpq_gettext("server sent data (\"D\" message) without prior row description (\"T\" message)\n"));
+						pqSaveErrorResult(conn);
+						/* Discard the unexpected message */
+						conn->inCursor += msgLength;
+					}
+					break;
+				case 'G':		/* Start Copy In */
+					if (getCopyStart(conn, PGRES_COPY_IN))
+						return;
+					conn->asyncStatus = PGASYNC_COPY_IN;
+					break;
+				case 'H':		/* Start Copy Out */
+					if (getCopyStart(conn, PGRES_COPY_OUT))
+						return;
+					conn->asyncStatus = PGASYNC_COPY_OUT;
+					conn->copy_already_done = 0;
+					break;
+				case 'W':		/* Start Copy Both */
+					if (getCopyStart(conn, PGRES_COPY_BOTH))
+						return;
+					conn->asyncStatus = PGASYNC_COPY_BOTH;
+					conn->copy_already_done = 0;
+					break;
+				case 'd':		/* Copy Data */
+
+					/*
+					 * If we see Copy Data, just silently drop it.  This would
+					 * only occur if application exits COPY OUT mode too
+					 * early.
+					 */
+					conn->inCursor += msgLength;
+					break;
+				case 'c':		/* Copy Done */
+
+					/*
+					 * If we see Copy Done, just silently drop it.  This is
+					 * the normal case during PQendcopy.  We will keep
+					 * swallowing data, expecting to see command-complete for
+					 * the COPY command.
+					 */
+					break;
+				default:
+					appendPQExpBuffer(&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);
+					/* not sure if we will see more, so go to ready state */
+					conn->asyncStatus = PGASYNC_READY;
+					/* Discard the unexpected message */
+					conn->inCursor += msgLength;
+					break;
+			}					/* switch on protocol character */
+		}
+		/* Successfully consumed this message */
+		if (conn->inCursor == conn->inStart + 5 + msgLength)
+		{
+			/* trace server-to-client message */
+			if (conn->Pfdebug)
+				pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
+
+			/* Normal case: parsing agrees with specified length */
+			conn->inStart = conn->inCursor;
+		}
+		else
+		{
+			/* Trouble --- report it */
+			appendPQExpBuffer(&conn->errorMessage,
+							  libpq_gettext("message contents do not agree with length in message type \"%c\"\n"),
+							  id);
+			/* build an error result holding the error message */
+			pqSaveErrorResult(conn);
+			conn->asyncStatus = PGASYNC_READY;
+			/* trust the specified message length as what to skip */
+			conn->inStart += 5 + msgLength;
+		}
+	}
+}
+
+/*
+ * handleSyncLoss: clean up after loss of message-boundary sync
+ *
+ * There isn't really a lot we can do here except abandon the connection.
+ */
+static void
+handleSyncLoss(PGconn *conn, char id, int msgLength)
+{
+	appendPQExpBuffer(&conn->errorMessage,
+					  libpq_gettext("lost synchronization with server: got message type \"%c\", length %d\n"),
+					  id, msgLength);
+	/* build an error result holding the error message */
+	pqSaveErrorResult(conn);
+	conn->asyncStatus = PGASYNC_READY;	/* drop out of PQgetResult wait loop */
+	/* flush input data since we're giving up on processing it */
+	pqDropConnection(conn, true);
+	conn->status = CONNECTION_BAD;	/* No more connection to backend */
+}
+
+/*
+ * parseInput subroutine to read a 'T' (row descriptions) message.
+ * We'll build a new PGresult structure (unless called for a Describe
+ * command for a prepared statement) containing the attribute data.
+ * Returns: 0 if processed message successfully, EOF to suspend parsing
+ * (the latter case is not actually used currently).
+ */
+static int
+getRowDescriptions(PGconn *conn, int msgLength)
+{
+	PGresult   *result;
+	int			nfields;
+	const char *errmsg;
+	int			i;
+
+	/*
+	 * When doing Describe for a prepared statement, there'll already be a
+	 * PGresult created by getParamDescriptions, and we should fill data into
+	 * that.  Otherwise, create a new, empty PGresult.
+	 */
+	if (!conn->cmd_queue_head ||
+		(conn->cmd_queue_head &&
+		 conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE))
+	{
+		if (conn->result)
+			result = conn->result;
+		else
+			result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
+	}
+	else
+		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 and message length. */
+	/* the next two bytes are the number of fields */
+	if (pqGetInt(&(result->numAttributes), 2, conn))
+	{
+		/* We should not run out of data here, so complain */
+		errmsg = libpq_gettext("insufficient data in \"T\" message");
+		goto advance_and_error;
+	}
+	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));
+	}
+
+	/* result->binary is true only if ALL columns are binary */
+	result->binary = (nfields > 0) ? 1 : 0;
+
+	/* get type info */
+	for (i = 0; i < nfields; i++)
+	{
+		int			tableid;
+		int			columnid;
+		int			typid;
+		int			typlen;
+		int			atttypmod;
+		int			format;
+
+		if (pqGets(&conn->workBuffer, conn) ||
+			pqGetInt(&tableid, 4, conn) ||
+			pqGetInt(&columnid, 2, conn) ||
+			pqGetInt(&typid, 4, conn) ||
+			pqGetInt(&typlen, 2, conn) ||
+			pqGetInt(&atttypmod, 4, conn) ||
+			pqGetInt(&format, 2, conn))
+		{
+			/* We should not run out of data here, so complain */
+			errmsg = libpq_gettext("insufficient data in \"T\" message");
+			goto advance_and_error;
+		}
+
+		/*
+		 * Since pqGetInt treats 2-byte integers as unsigned, we need to
+		 * coerce these results to signed form.
+		 */
+		columnid = (int) ((int16) columnid);
+		typlen = (int) ((int16) typlen);
+		format = (int) ((int16) format);
+
+		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 = tableid;
+		result->attDescs[i].columnid = columnid;
+		result->attDescs[i].format = format;
+		result->attDescs[i].typid = typid;
+		result->attDescs[i].typlen = typlen;
+		result->attDescs[i].atttypmod = atttypmod;
+
+		if (format != 1)
+			result->binary = 0;
+	}
+
+	/* Success! */
+	conn->result = result;
+
+	/*
+	 * If we're doing a Describe, we're done, and ready to pass the result
+	 * back to the client.
+	 */
+	if ((!conn->cmd_queue_head) ||
+		(conn->cmd_queue_head &&
+		 conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE))
+	{
+		conn->asyncStatus = PGASYNC_READY;
+		return 0;
+	}
+
+	/*
+	 * 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 unsaved result, if any */
+	if (result && result != conn->result)
+		PQclear(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");
+
+	appendPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
+	pqSaveErrorResult(conn);
+
+	/*
+	 * Show the message as fully consumed, else pqParseInput3 will overwrite
+	 * our error with a complaint about that.
+	 */
+	conn->inCursor = conn->inStart + 5 + msgLength;
+
+	/*
+	 * Return zero to allow input parsing to continue.  Subsequent "D"
+	 * messages will be ignored until we get to end of data, since an error
+	 * result is already set up.
+	 */
+	return 0;
+}
+
+/*
+ * parseInput subroutine to read a 't' (ParameterDescription) message.
+ * We'll build a new PGresult structure containing the parameter data.
+ * Returns: 0 if processed message successfully, EOF to suspend parsing
+ * (the latter case is not actually used currently).
+ */
+static int
+getParamDescriptions(PGconn *conn, int msgLength)
+{
+	PGresult   *result;
+	const char *errmsg = NULL;	/* means "out of memory", see below */
+	int			nparams;
+	int			i;
+
+	result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
+	if (!result)
+		goto advance_and_error;
+
+	/* parseInput already read the 't' label and message length. */
+	/* the next two bytes are the number of parameters */
+	if (pqGetInt(&(result->numParameters), 2, conn))
+		goto not_enough_data;
+	nparams = result->numParameters;
+
+	/* allocate space for the parameter descriptors */
+	if (nparams > 0)
+	{
+		result->paramDescs = (PGresParamDesc *)
+			pqResultAlloc(result, nparams * sizeof(PGresParamDesc), true);
+		if (!result->paramDescs)
+			goto advance_and_error;
+		MemSet(result->paramDescs, 0, nparams * sizeof(PGresParamDesc));
+	}
+
+	/* get parameter info */
+	for (i = 0; i < nparams; i++)
+	{
+		int			typid;
+
+		if (pqGetInt(&typid, 4, conn))
+			goto not_enough_data;
+		result->paramDescs[i].typid = typid;
+	}
+
+	/* Success! */
+	conn->result = result;
+
+	return 0;
+
+not_enough_data:
+	errmsg = libpq_gettext("insufficient data in \"t\" message");
+
+advance_and_error:
+	/* Discard unsaved result, if any */
+	if (result && result != conn->result)
+		PQclear(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");
+	appendPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
+	pqSaveErrorResult(conn);
+
+	/*
+	 * Show the message as fully consumed, else pqParseInput3 will overwrite
+	 * our error with a complaint about that.
+	 */
+	conn->inCursor = conn->inStart + 5 + msgLength;
+
+	/*
+	 * Return zero to allow input parsing to continue.  Essentially, we've
+	 * replaced the COMMAND_OK result with an error result, but since this
+	 * doesn't affect the protocol state, it's fine.
+	 */
+	return 0;
+}
+
+/*
+ * parseInput subroutine to read a 'D' (row data) message.
+ * We fill rowbuf with column pointers and then call the row processor.
+ * Returns: 0 if processed message successfully, EOF to suspend parsing
+ * (the latter case is not actually used currently).
+ */
+static int
+getAnotherTuple(PGconn *conn, int msgLength)
+{
+	PGresult   *result = conn->result;
+	int			nfields = result->numAttributes;
+	const char *errmsg;
+	PGdataValue *rowbuf;
+	int			tupnfields;		/* # fields from tuple */
+	int			vlen;			/* length of the current field value */
+	int			i;
+
+	/* Get the field count and make sure it's what we expect */
+	if (pqGetInt(&tupnfields, 2, conn))
+	{
+		/* We should not run out of data here, so complain */
+		errmsg = libpq_gettext("insufficient data in \"D\" message");
+		goto advance_and_error;
+	}
+
+	if (tupnfields != nfields)
+	{
+		errmsg = libpq_gettext("unexpected field count in \"D\" message");
+		goto advance_and_error;
+	}
+
+	/* 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;
+	}
+
+	/* Scan the fields */
+	for (i = 0; i < nfields; i++)
+	{
+		/* get the value length */
+		if (pqGetInt(&vlen, 4, conn))
+		{
+			/* We should not run out of data here, so complain */
+			errmsg = libpq_gettext("insufficient data in \"D\" message");
+			goto advance_and_error;
+		}
+		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))
+			{
+				/* We should not run out of data here, so complain */
+				errmsg = libpq_gettext("insufficient data in \"D\" message");
+				goto advance_and_error;
+			}
+		}
+	}
+
+	/* Process the collected row */
+	errmsg = NULL;
+	if (pqRowProcessor(conn, &errmsg))
+		return 0;				/* normal, successful exit */
+
+	/* pqRowProcessor failed, fall through to report it */
+
+advance_and_error:
+
+	/*
+	 * 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");
+
+	appendPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
+	pqSaveErrorResult(conn);
+
+	/*
+	 * Show the message as fully consumed, else pqParseInput3 will overwrite
+	 * our error with a complaint about that.
+	 */
+	conn->inCursor = conn->inStart + 5 + msgLength;
+
+	/*
+	 * Return zero to allow input parsing to continue.  Subsequent "D"
+	 * messages will be ignored until we get to end of data, since an error
+	 * result is already set up.
+	 */
+	return 0;
+}
+
+
+/*
+ * 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 and length have already been consumed.
+ * Exit: returns 0 if successfully consumed message.
+ *		 returns EOF if not enough data.
+ */
+int
+pqGetErrorNotice3(PGconn *conn, bool isError)
+{
+	PGresult   *res = NULL;
+	bool		have_position = false;
+	PQExpBufferData workBuf;
+	char		id;
+
+	/* If in pipeline mode, set error indicator for it */
+	if (isError && conn->pipelineStatus != PQ_PIPELINE_OFF)
+		conn->pipelineStatus = PQ_PIPELINE_ABORTED;
+
+	/*
+	 * 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 fields 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.  We shouldn't use
+	 * conn->errorMessage either, since this might be only a notice.
+	 */
+	initPQExpBuffer(&workBuf);
+
+	/*
+	 * Make a PGresult to hold the accumulated fields.  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;
+
+	/*
+	 * Read the fields and save into res.
+	 *
+	 * While at it, save the SQLSTATE in conn->last_sqlstate, and note whether
+	 * we saw a PG_DIAG_STATEMENT_POSITION field.
+	 */
+	for (;;)
+	{
+		if (pqGetc(&id, conn))
+			goto fail;
+		if (id == '\0')
+			break;				/* terminator found */
+		if (pqGets(&workBuf, conn))
+			goto fail;
+		pqSaveMessageField(res, id, workBuf.data);
+		if (id == PG_DIAG_SQLSTATE)
+			strlcpy(conn->last_sqlstate, workBuf.data,
+					sizeof(conn->last_sqlstate));
+		else if (id == PG_DIAG_STATEMENT_POSITION)
+			have_position = true;
+	}
+
+	/*
+	 * Save the active query text, if any, into res as well; but only if we
+	 * might need it for an error cursor display, which is only true if there
+	 * is a PG_DIAG_STATEMENT_POSITION field.
+	 */
+	if (have_position && res && conn->cmd_queue_head && conn->cmd_queue_head->query)
+		res->errQuery = pqResultStrdup(res, conn->cmd_queue_head->query);
+
+	/*
+	 * Now build the "overall" error message for PQresultErrorMessage.
+	 */
+	resetPQExpBuffer(&workBuf);
+	pqBuildErrorMessage3(&workBuf, res, conn->verbosity, conn->show_context);
+
+	/*
+	 * Either save error as current async result, or just emit the notice.
+	 */
+	if (isError)
+	{
+		if (res)
+			pqSetResultError(res, &workBuf);
+		pqClearAsyncResult(conn);	/* redundant, but be safe */
+		conn->result = res;
+		if (PQExpBufferDataBroken(workBuf))
+			appendPQExpBufferStr(&conn->errorMessage,
+								 libpq_gettext("out of memory\n"));
+		else
+			appendPQExpBufferStr(&conn->errorMessage, workBuf.data);
+	}
+	else
+	{
+		/* if we couldn't allocate the result set, just discard the NOTICE */
+		if (res)
+		{
+			/*
+			 * We can cheat a little here and not copy the message.  But if we
+			 * were unlucky enough to run out of memory while filling workBuf,
+			 * insert "out of memory", as in pqSetResultError.
+			 */
+			if (PQExpBufferDataBroken(workBuf))
+				res->errMsg = libpq_gettext("out of memory\n");
+			else
+				res->errMsg = workBuf.data;
+			if (res->noticeHooks.noticeRec != NULL)
+				res->noticeHooks.noticeRec(res->noticeHooks.noticeRecArg, res);
+			PQclear(res);
+		}
+	}
+
+	termPQExpBuffer(&workBuf);
+	return 0;
+
+fail:
+	PQclear(res);
+	termPQExpBuffer(&workBuf);
+	return EOF;
+}
+
+/*
+ * Construct an error message from the fields in the given PGresult,
+ * appending it to the contents of "msg".
+ */
+void
+pqBuildErrorMessage3(PQExpBuffer msg, const PGresult *res,
+					 PGVerbosity verbosity, PGContextVisibility show_context)
+{
+	const char *val;
+	const char *querytext = NULL;
+	int			querypos = 0;
+
+	/* If we couldn't allocate a PGresult, just say "out of memory" */
+	if (res == NULL)
+	{
+		appendPQExpBufferStr(msg, libpq_gettext("out of memory\n"));
+		return;
+	}
+
+	/*
+	 * If we don't have any broken-down fields, just return the base message.
+	 * This mainly applies if we're given a libpq-generated error result.
+	 */
+	if (res->errFields == NULL)
+	{
+		if (res->errMsg && res->errMsg[0])
+			appendPQExpBufferStr(msg, res->errMsg);
+		else
+			appendPQExpBufferStr(msg, libpq_gettext("no error message available\n"));
+		return;
+	}
+
+	/* Else build error message from relevant fields */
+	val = PQresultErrorField(res, PG_DIAG_SEVERITY);
+	if (val)
+		appendPQExpBuffer(msg, "%s:  ", val);
+
+	if (verbosity == PQERRORS_SQLSTATE)
+	{
+		/*
+		 * If we have a SQLSTATE, print that and nothing else.  If not (which
+		 * shouldn't happen for server-generated errors, but might possibly
+		 * happen for libpq-generated ones), fall back to TERSE format, as
+		 * that seems better than printing nothing at all.
+		 */
+		val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
+		if (val)
+		{
+			appendPQExpBuffer(msg, "%s\n", val);
+			return;
+		}
+		verbosity = PQERRORS_TERSE;
+	}
+
+	if (verbosity == PQERRORS_VERBOSE)
+	{
+		val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
+		if (val)
+			appendPQExpBuffer(msg, "%s: ", val);
+	}
+	val = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
+	if (val)
+		appendPQExpBufferStr(msg, val);
+	val = PQresultErrorField(res, PG_DIAG_STATEMENT_POSITION);
+	if (val)
+	{
+		if (verbosity != PQERRORS_TERSE && res->errQuery != NULL)
+		{
+			/* emit position as a syntax cursor display */
+			querytext = res->errQuery;
+			querypos = atoi(val);
+		}
+		else
+		{
+			/* emit position as text addition to primary message */
+			/* translator: %s represents a digit string */
+			appendPQExpBuffer(msg, libpq_gettext(" at character %s"),
+							  val);
+		}
+	}
+	else
+	{
+		val = PQresultErrorField(res, PG_DIAG_INTERNAL_POSITION);
+		if (val)
+		{
+			querytext = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
+			if (verbosity != PQERRORS_TERSE && querytext != NULL)
+			{
+				/* emit position as a syntax cursor display */
+				querypos = atoi(val);
+			}
+			else
+			{
+				/* emit position as text addition to primary message */
+				/* translator: %s represents a digit string */
+				appendPQExpBuffer(msg, libpq_gettext(" at character %s"),
+								  val);
+			}
+		}
+	}
+	appendPQExpBufferChar(msg, '\n');
+	if (verbosity != PQERRORS_TERSE)
+	{
+		if (querytext && querypos > 0)
+			reportErrorPosition(msg, querytext, querypos,
+								res->client_encoding);
+		val = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
+		if (val)
+			appendPQExpBuffer(msg, libpq_gettext("DETAIL:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
+		if (val)
+			appendPQExpBuffer(msg, libpq_gettext("HINT:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
+		if (val)
+			appendPQExpBuffer(msg, libpq_gettext("QUERY:  %s\n"), val);
+		if (show_context == PQSHOW_CONTEXT_ALWAYS ||
+			(show_context == PQSHOW_CONTEXT_ERRORS &&
+			 res->resultStatus == PGRES_FATAL_ERROR))
+		{
+			val = PQresultErrorField(res, PG_DIAG_CONTEXT);
+			if (val)
+				appendPQExpBuffer(msg, libpq_gettext("CONTEXT:  %s\n"),
+								  val);
+		}
+	}
+	if (verbosity == PQERRORS_VERBOSE)
+	{
+		val = PQresultErrorField(res, PG_DIAG_SCHEMA_NAME);
+		if (val)
+			appendPQExpBuffer(msg,
+							  libpq_gettext("SCHEMA NAME:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_TABLE_NAME);
+		if (val)
+			appendPQExpBuffer(msg,
+							  libpq_gettext("TABLE NAME:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_COLUMN_NAME);
+		if (val)
+			appendPQExpBuffer(msg,
+							  libpq_gettext("COLUMN NAME:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_DATATYPE_NAME);
+		if (val)
+			appendPQExpBuffer(msg,
+							  libpq_gettext("DATATYPE NAME:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_CONSTRAINT_NAME);
+		if (val)
+			appendPQExpBuffer(msg,
+							  libpq_gettext("CONSTRAINT NAME:  %s\n"), val);
+	}
+	if (verbosity == PQERRORS_VERBOSE)
+	{
+		const char *valf;
+		const char *vall;
+
+		valf = PQresultErrorField(res, PG_DIAG_SOURCE_FILE);
+		vall = PQresultErrorField(res, PG_DIAG_SOURCE_LINE);
+		val = PQresultErrorField(res, PG_DIAG_SOURCE_FUNCTION);
+		if (val || valf || vall)
+		{
+			appendPQExpBufferStr(msg, libpq_gettext("LOCATION:  "));
+			if (val)
+				appendPQExpBuffer(msg, libpq_gettext("%s, "), val);
+			if (valf && vall)	/* unlikely we'd have just one */
+				appendPQExpBuffer(msg, libpq_gettext("%s:%s"),
+								  valf, vall);
+			appendPQExpBufferChar(msg, '\n');
+		}
+	}
+}
+
+/*
+ * Add an error-location display to the error message under construction.
+ *
+ * The cursor location is measured in logical characters; the query string
+ * is presumed to be in the specified encoding.
+ */
+static void
+reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
+{
+#define DISPLAY_SIZE	60		/* screen width limit, in screen cols */
+#define MIN_RIGHT_CUT	10		/* try to keep this far away from EOL */
+
+	char	   *wquery;
+	int			slen,
+				cno,
+				i,
+			   *qidx,
+			   *scridx,
+				qoffset,
+				scroffset,
+				ibeg,
+				iend,
+				loc_line;
+	bool		mb_encoding,
+				beg_trunc,
+				end_trunc;
+
+	/* Convert loc from 1-based to 0-based; no-op if out of range */
+	loc--;
+	if (loc < 0)
+		return;
+
+	/* Need a writable copy of the query */
+	wquery = strdup(query);
+	if (wquery == NULL)
+		return;					/* fail silently if out of memory */
+
+	/*
+	 * Each character might occupy multiple physical bytes in the string, and
+	 * in some Far Eastern character sets it might take more than one screen
+	 * column as well.  We compute the starting byte offset and starting
+	 * screen column of each logical character, and store these in qidx[] and
+	 * scridx[] respectively.
+	 */
+
+	/* we need a safe allocation size... */
+	slen = strlen(wquery) + 1;
+
+	qidx = (int *) malloc(slen * sizeof(int));
+	if (qidx == NULL)
+	{
+		free(wquery);
+		return;
+	}
+	scridx = (int *) malloc(slen * sizeof(int));
+	if (scridx == NULL)
+	{
+		free(qidx);
+		free(wquery);
+		return;
+	}
+
+	/* We can optimize a bit if it's a single-byte encoding */
+	mb_encoding = (pg_encoding_max_length(encoding) != 1);
+
+	/*
+	 * Within the scanning loop, cno is the current character's logical
+	 * number, qoffset is its offset in wquery, and scroffset is its starting
+	 * logical screen column (all indexed from 0).  "loc" is the logical
+	 * character number of the error location.  We scan to determine loc_line
+	 * (the 1-based line number containing loc) and ibeg/iend (first character
+	 * number and last+1 character number of the line containing loc). Note
+	 * that qidx[] and scridx[] are filled only as far as iend.
+	 */
+	qoffset = 0;
+	scroffset = 0;
+	loc_line = 1;
+	ibeg = 0;
+	iend = -1;					/* -1 means not set yet */
+
+	for (cno = 0; wquery[qoffset] != '\0'; cno++)
+	{
+		char		ch = wquery[qoffset];
+
+		qidx[cno] = qoffset;
+		scridx[cno] = scroffset;
+
+		/*
+		 * Replace tabs with spaces in the writable copy.  (Later we might
+		 * want to think about coping with their variable screen width, but
+		 * not today.)
+		 */
+		if (ch == '\t')
+			wquery[qoffset] = ' ';
+
+		/*
+		 * If end-of-line, count lines and mark positions. Each \r or \n
+		 * counts as a line except when \r \n appear together.
+		 */
+		else if (ch == '\r' || ch == '\n')
+		{
+			if (cno < loc)
+			{
+				if (ch == '\r' ||
+					cno == 0 ||
+					wquery[qidx[cno - 1]] != '\r')
+					loc_line++;
+				/* extract beginning = last line start before loc. */
+				ibeg = cno + 1;
+			}
+			else
+			{
+				/* set extract end. */
+				iend = cno;
+				/* done scanning. */
+				break;
+			}
+		}
+
+		/* Advance */
+		if (mb_encoding)
+		{
+			int			w;
+
+			w = pg_encoding_dsplen(encoding, &wquery[qoffset]);
+			/* treat any non-tab control chars as width 1 */
+			if (w <= 0)
+				w = 1;
+			scroffset += w;
+			qoffset += PQmblenBounded(&wquery[qoffset], encoding);
+		}
+		else
+		{
+			/* We assume wide chars only exist in multibyte encodings */
+			scroffset++;
+			qoffset++;
+		}
+	}
+	/* Fix up if we didn't find an end-of-line after loc */
+	if (iend < 0)
+	{
+		iend = cno;				/* query length in chars, +1 */
+		qidx[iend] = qoffset;
+		scridx[iend] = scroffset;
+	}
+
+	/* Print only if loc is within computed query length */
+	if (loc <= cno)
+	{
+		/* If the line extracted is too long, we truncate it. */
+		beg_trunc = false;
+		end_trunc = false;
+		if (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+		{
+			/*
+			 * We first truncate right if it is enough.  This code might be
+			 * off a space or so on enforcing MIN_RIGHT_CUT if there's a wide
+			 * character right there, but that should be okay.
+			 */
+			if (scridx[ibeg] + DISPLAY_SIZE >= scridx[loc] + MIN_RIGHT_CUT)
+			{
+				while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+					iend--;
+				end_trunc = true;
+			}
+			else
+			{
+				/* Truncate right if not too close to loc. */
+				while (scridx[loc] + MIN_RIGHT_CUT < scridx[iend])
+				{
+					iend--;
+					end_trunc = true;
+				}
+
+				/* Truncate left if still too long. */
+				while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+				{
+					ibeg++;
+					beg_trunc = true;
+				}
+			}
+		}
+
+		/* truncate working copy at desired endpoint */
+		wquery[qidx[iend]] = '\0';
+
+		/* Begin building the finished message. */
+		i = msg->len;
+		appendPQExpBuffer(msg, libpq_gettext("LINE %d: "), loc_line);
+		if (beg_trunc)
+			appendPQExpBufferStr(msg, "...");
+
+		/*
+		 * While we have the prefix in the msg buffer, compute its screen
+		 * width.
+		 */
+		scroffset = 0;
+		for (; i < msg->len; i += PQmblenBounded(&msg->data[i], encoding))
+		{
+			int			w = pg_encoding_dsplen(encoding, &msg->data[i]);
+
+			if (w <= 0)
+				w = 1;
+			scroffset += w;
+		}
+
+		/* Finish up the LINE message line. */
+		appendPQExpBufferStr(msg, &wquery[qidx[ibeg]]);
+		if (end_trunc)
+			appendPQExpBufferStr(msg, "...");
+		appendPQExpBufferChar(msg, '\n');
+
+		/* Now emit the cursor marker line. */
+		scroffset += scridx[loc] - scridx[ibeg];
+		for (i = 0; i < scroffset; i++)
+			appendPQExpBufferChar(msg, ' ');
+		appendPQExpBufferChar(msg, '^');
+		appendPQExpBufferChar(msg, '\n');
+	}
+
+	/* Clean up. */
+	free(scridx);
+	free(qidx);
+	free(wquery);
+}
+
+
+/*
+ * Attempt to read a ParameterStatus message.
+ * This is possible in several places, so we break it out as a subroutine.
+ * Entry: 'S' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed message.
+ *		 returns EOF if not enough data.
+ */
+static int
+getParameterStatus(PGconn *conn)
+{
+	PQExpBufferData valueBuf;
+
+	/* Get the parameter name */
+	if (pqGets(&conn->workBuffer, conn))
+		return EOF;
+	/* Get the parameter value (could be large) */
+	initPQExpBuffer(&valueBuf);
+	if (pqGets(&valueBuf, conn))
+	{
+		termPQExpBuffer(&valueBuf);
+		return EOF;
+	}
+	/* And save it */
+	pqSaveParameterStatus(conn, conn->workBuffer.data, valueBuf.data);
+	termPQExpBuffer(&valueBuf);
+	return 0;
+}
+
+
+/*
+ * 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;
+	char	   *svname;
+	int			nmlen;
+	int			extralen;
+	PGnotify   *newNotify;
+
+	if (pqGetInt(&be_pid, 4, conn))
+		return EOF;
+	if (pqGets(&conn->workBuffer, conn))
+		return EOF;
+	/* must save name while getting extra string */
+	svname = strdup(conn->workBuffer.data);
+	if (!svname)
+		return EOF;
+	if (pqGets(&conn->workBuffer, conn))
+	{
+		free(svname);
+		return EOF;
+	}
+
+	/*
+	 * Store the strings 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(svname);
+	extralen = strlen(conn->workBuffer.data);
+	newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + extralen + 2);
+	if (newNotify)
+	{
+		newNotify->relname = (char *) newNotify + sizeof(PGnotify);
+		strcpy(newNotify->relname, svname);
+		newNotify->extra = newNotify->relname + nmlen + 1;
+		strcpy(newNotify->extra, conn->workBuffer.data);
+		newNotify->be_pid = be_pid;
+		newNotify->next = NULL;
+		if (conn->notifyTail)
+			conn->notifyTail->next = newNotify;
+		else
+			conn->notifyHead = newNotify;
+		conn->notifyTail = newNotify;
+	}
+
+	free(svname);
+	return 0;
+}
+
+/*
+ * getCopyStart - process CopyInResponse, CopyOutResponse or
+ * CopyBothResponse message
+ *
+ * parseInput already read the message type and length.
+ */
+static int
+getCopyStart(PGconn *conn, ExecStatusType copytype)
+{
+	PGresult   *result;
+	int			nfields;
+	int			i;
+
+	result = PQmakeEmptyPGresult(conn, copytype);
+	if (!result)
+		goto failure;
+
+	if (pqGetc(&conn->copy_is_binary, conn))
+		goto failure;
+	result->binary = conn->copy_is_binary;
+	/* the next two bytes are the number of fields	*/
+	if (pqGetInt(&(result->numAttributes), 2, conn))
+		goto failure;
+	nfields = result->numAttributes;
+
+	/* allocate space for the attribute descriptors */
+	if (nfields > 0)
+	{
+		result->attDescs = (PGresAttDesc *)
+			pqResultAlloc(result, nfields * sizeof(PGresAttDesc), true);
+		if (!result->attDescs)
+			goto failure;
+		MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
+	}
+
+	for (i = 0; i < nfields; i++)
+	{
+		int			format;
+
+		if (pqGetInt(&format, 2, conn))
+			goto failure;
+
+		/*
+		 * Since pqGetInt treats 2-byte integers as unsigned, we need to
+		 * coerce these results to signed form.
+		 */
+		format = (int) ((int16) format);
+		result->attDescs[i].format = format;
+	}
+
+	/* Success! */
+	conn->result = result;
+	return 0;
+
+failure:
+	PQclear(result);
+	return EOF;
+}
+
+/*
+ * getReadyForQuery - process ReadyForQuery message
+ */
+static int
+getReadyForQuery(PGconn *conn)
+{
+	char		xact_status;
+
+	if (pqGetc(&xact_status, conn))
+		return EOF;
+	switch (xact_status)
+	{
+		case 'I':
+			conn->xactStatus = PQTRANS_IDLE;
+			break;
+		case 'T':
+			conn->xactStatus = PQTRANS_INTRANS;
+			break;
+		case 'E':
+			conn->xactStatus = PQTRANS_INERROR;
+			break;
+		default:
+			conn->xactStatus = PQTRANS_UNKNOWN;
+			break;
+	}
+
+	return 0;
+}
+
+/*
+ * getCopyDataMessage - fetch next CopyData message, process async messages
+ *
+ * Returns length word of CopyData message (> 0), or 0 if no complete
+ * message available, -1 if end of copy, -2 if error.
+ */
+static int
+getCopyDataMessage(PGconn *conn)
+{
+	char		id;
+	int			msgLength;
+	int			avail;
+
+	for (;;)
+	{
+		/*
+		 * Do we have the next input message?  To make life simpler for async
+		 * callers, we keep returning 0 until the next message is fully
+		 * available, even if it is not Copy Data.
+		 */
+		conn->inCursor = conn->inStart;
+		if (pqGetc(&id, conn))
+			return 0;
+		if (pqGetInt(&msgLength, 4, conn))
+			return 0;
+		if (msgLength < 4)
+		{
+			handleSyncLoss(conn, id, msgLength);
+			return -2;
+		}
+		avail = conn->inEnd - conn->inCursor;
+		if (avail < msgLength - 4)
+		{
+			/*
+			 * Before returning, enlarge the input buffer if needed to hold
+			 * the whole message.  See notes in parseInput.
+			 */
+			if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength - 4,
+									 conn))
+			{
+				/*
+				 * XXX add some better recovery code... plan is to skip over
+				 * the message using its length, then report an error. For the
+				 * moment, just treat this like loss of sync (which indeed it
+				 * might be!)
+				 */
+				handleSyncLoss(conn, id, msgLength);
+				return -2;
+			}
+			return 0;
+		}
+
+		/*
+		 * If it's a legitimate async message type, process it.  (NOTIFY
+		 * messages are not currently possible here, but we handle them for
+		 * completeness.)  Otherwise, if it's anything except Copy Data,
+		 * report end-of-copy.
+		 */
+		switch (id)
+		{
+			case 'A':			/* NOTIFY */
+				if (getNotify(conn))
+					return 0;
+				break;
+			case 'N':			/* NOTICE */
+				if (pqGetErrorNotice3(conn, false))
+					return 0;
+				break;
+			case 'S':			/* ParameterStatus */
+				if (getParameterStatus(conn))
+					return 0;
+				break;
+			case 'd':			/* Copy Data, pass it back to caller */
+				return msgLength;
+			case 'c':
+
+				/*
+				 * If this is a CopyDone message, exit COPY_OUT mode and let
+				 * caller read status with PQgetResult().  If we're in
+				 * COPY_BOTH mode, return to COPY_IN mode.
+				 */
+				if (conn->asyncStatus == PGASYNC_COPY_BOTH)
+					conn->asyncStatus = PGASYNC_COPY_IN;
+				else
+					conn->asyncStatus = PGASYNC_BUSY;
+				return -1;
+			default:			/* treat as end of copy */
+
+				/*
+				 * Any other message terminates either COPY_IN or COPY_BOTH
+				 * mode.
+				 */
+				conn->asyncStatus = PGASYNC_BUSY;
+				return -1;
+		}
+
+		/* trace server-to-client message */
+		if (conn->Pfdebug)
+			pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
+
+		/* Drop the processed message and loop around for another */
+		conn->inStart = conn->inCursor;
+	}
+}
+
+/*
+ * PQgetCopyData - read a row of data from the backend during COPY OUT
+ * or COPY BOTH
+ *
+ * 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
+pqGetCopyData3(PGconn *conn, char **buffer, int async)
+{
+	int			msgLength;
+
+	for (;;)
+	{
+		/*
+		 * Collect the next input message.  To make life simpler for async
+		 * callers, we keep returning 0 until the next message is fully
+		 * available, even if it is not Copy Data.
+		 */
+		msgLength = getCopyDataMessage(conn);
+		if (msgLength < 0)
+			return msgLength;	/* end-of-copy or error */
+		if (msgLength == 0)
+		{
+			/* 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;
+			continue;
+		}
+
+		/*
+		 * Drop zero-length messages (shouldn't happen anyway).  Otherwise
+		 * pass the data back to the caller.
+		 */
+		msgLength -= 4;
+		if (msgLength > 0)
+		{
+			*buffer = (char *) malloc(msgLength + 1);
+			if (*buffer == NULL)
+			{
+				appendPQExpBufferStr(&conn->errorMessage,
+									 libpq_gettext("out of memory\n"));
+				return -2;
+			}
+			memcpy(*buffer, &conn->inBuffer[conn->inCursor], msgLength);
+			(*buffer)[msgLength] = '\0';	/* Add terminating null */
+
+			/* Mark message consumed */
+			conn->inStart = conn->inCursor + msgLength;
+
+			return msgLength;
+		}
+
+		/* Empty, so drop it and loop around for another */
+		conn->inStart = conn->inCursor;
+	}
+}
+
+/*
+ * PQgetline - gets a newline-terminated string from the backend.
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqGetline3(PGconn *conn, char *s, int maxlen)
+{
+	int			status;
+
+	if (conn->sock == PGINVALID_SOCKET ||
+		(conn->asyncStatus != PGASYNC_COPY_OUT &&
+		 conn->asyncStatus != PGASYNC_COPY_BOTH) ||
+		conn->copy_is_binary)
+	{
+		appendPQExpBufferStr(&conn->errorMessage,
+							 libpq_gettext("PQgetline: not doing text COPY OUT\n"));
+		*s = '\0';
+		return EOF;
+	}
+
+	while ((status = PQgetlineAsync(conn, s, maxlen - 1)) == 0)
+	{
+		/* need to load more data */
+		if (pqWait(true, false, conn) ||
+			pqReadData(conn) < 0)
+		{
+			*s = '\0';
+			return EOF;
+		}
+	}
+
+	if (status < 0)
+	{
+		/* End of copy detected; gin up old-style terminator */
+		strcpy(s, "\\.");
+		return 0;
+	}
+
+	/* Add null terminator, and strip trailing \n if present */
+	if (s[status - 1] == '\n')
+	{
+		s[status - 1] = '\0';
+		return 0;
+	}
+	else
+	{
+		s[status] = '\0';
+		return 1;
+	}
+}
+
+/*
+ * PQgetlineAsync - gets a COPY data row without blocking.
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize)
+{
+	int			msgLength;
+	int			avail;
+
+	if (conn->asyncStatus != PGASYNC_COPY_OUT
+		&& conn->asyncStatus != PGASYNC_COPY_BOTH)
+		return -1;				/* we are not doing a copy... */
+
+	/*
+	 * Recognize the next input message.  To make life simpler for async
+	 * callers, we keep returning 0 until the next message is fully available
+	 * even if it is not Copy Data.  This should keep PQendcopy from blocking.
+	 * (Note: unlike pqGetCopyData3, we do not change asyncStatus here.)
+	 */
+	msgLength = getCopyDataMessage(conn);
+	if (msgLength < 0)
+		return -1;				/* end-of-copy or error */
+	if (msgLength == 0)
+		return 0;				/* no data yet */
+
+	/*
+	 * Move data from libpq's buffer to the caller's.  In the case where a
+	 * prior call found the caller's buffer too small, we use
+	 * conn->copy_already_done to remember how much of the row was already
+	 * returned to the caller.
+	 */
+	conn->inCursor += conn->copy_already_done;
+	avail = msgLength - 4 - conn->copy_already_done;
+	if (avail <= bufsize)
+	{
+		/* Able to consume the whole message */
+		memcpy(buffer, &conn->inBuffer[conn->inCursor], avail);
+		/* Mark message consumed */
+		conn->inStart = conn->inCursor + avail;
+		/* Reset state for next time */
+		conn->copy_already_done = 0;
+		return avail;
+	}
+	else
+	{
+		/* We must return a partial message */
+		memcpy(buffer, &conn->inBuffer[conn->inCursor], bufsize);
+		/* The message is NOT consumed from libpq's buffer */
+		conn->copy_already_done += bufsize;
+		return bufsize;
+	}
+}
+
+/*
+ * PQendcopy
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqEndcopy3(PGconn *conn)
+{
+	PGresult   *result;
+
+	if (conn->asyncStatus != PGASYNC_COPY_IN &&
+		conn->asyncStatus != PGASYNC_COPY_OUT &&
+		conn->asyncStatus != PGASYNC_COPY_BOTH)
+	{
+		appendPQExpBufferStr(&conn->errorMessage,
+							 libpq_gettext("no COPY in progress\n"));
+		return 1;
+	}
+
+	/* Send the CopyDone message if needed */
+	if (conn->asyncStatus == PGASYNC_COPY_IN ||
+		conn->asyncStatus == PGASYNC_COPY_BOTH)
+	{
+		if (pqPutMsgStart('c', conn) < 0 ||
+			pqPutMsgEnd(conn) < 0)
+			return 1;
+
+		/*
+		 * If we sent the COPY command in extended-query mode, we must issue a
+		 * Sync as well.
+		 */
+		if (conn->cmd_queue_head &&
+			conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE)
+		{
+			if (pqPutMsgStart('S', conn) < 0 ||
+				pqPutMsgEnd(conn) < 0)
+				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;
+
+	/* Return to active duty */
+	conn->asyncStatus = PGASYNC_BUSY;
+
+	/*
+	 * Non blocking connections may have to abort at this point.  If everyone
+	 * played the game there should be no problem, but in error scenarios the
+	 * expected messages may not have arrived yet.  (We are assuming that the
+	 * backend's packetizing will ensure that CommandComplete arrives along
+	 * with the CopyDone; are there corner cases where that doesn't happen?)
+	 */
+	if (pqIsnonblocking(conn) && PQisBusy(conn))
+		return 1;
+
+	/* 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);
+
+	return 1;
+}
+
+
+/*
+ * PQfn - Send a function call to the POSTGRES backend.
+ *
+ * See fe-exec.c for documentation.
+ */
+PGresult *
+pqFunctionCall3(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			msgLength;
+	int			avail;
+	int			i;
+
+	/* already validated by PQfn */
+	Assert(conn->pipelineStatus == PQ_PIPELINE_OFF);
+
+	/* PQfn already validated connection state */
+
+	if (pqPutMsgStart('F', conn) < 0 || /* function call msg */
+		pqPutInt(fnid, 4, conn) < 0 ||	/* function id */
+		pqPutInt(1, 2, conn) < 0 || /* # of format codes */
+		pqPutInt(1, 2, conn) < 0 || /* format code: BINARY */
+		pqPutInt(nargs, 2, conn) < 0)	/* # of args */
+	{
+		/* error message should be set up already */
+		return NULL;
+	}
+
+	for (i = 0; i < nargs; ++i)
+	{							/* len.int4 + contents	   */
+		if (pqPutInt(args[i].len, 4, conn))
+			return NULL;
+		if (args[i].len == -1)
+			continue;			/* it's NULL */
+
+		if (args[i].isint)
+		{
+			if (pqPutInt(args[i].u.integer, args[i].len, conn))
+				return NULL;
+		}
+		else
+		{
+			if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
+				return NULL;
+		}
+	}
+
+	if (pqPutInt(1, 2, conn) < 0)	/* result format code: BINARY */
+		return NULL;
+
+	if (pqPutMsgEnd(conn) < 0 ||
+		pqFlush(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.
+		 */
+		needInput = true;
+
+		conn->inCursor = conn->inStart;
+		if (pqGetc(&id, conn))
+			continue;
+		if (pqGetInt(&msgLength, 4, conn))
+			continue;
+
+		/*
+		 * Try to validate message type/length here.  A length less than 4 is
+		 * definitely broken.  Large lengths should only be believed for a few
+		 * message types.
+		 */
+		if (msgLength < 4)
+		{
+			handleSyncLoss(conn, id, msgLength);
+			break;
+		}
+		if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
+		{
+			handleSyncLoss(conn, id, msgLength);
+			break;
+		}
+
+		/*
+		 * Can't process if message body isn't all here yet.
+		 */
+		msgLength -= 4;
+		avail = conn->inEnd - conn->inCursor;
+		if (avail < msgLength)
+		{
+			/*
+			 * Before looping, enlarge the input buffer if needed to hold the
+			 * whole message.  See notes in parseInput.
+			 */
+			if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
+									 conn))
+			{
+				/*
+				 * XXX add some better recovery code... plan is to skip over
+				 * the message using its length, then report an error. For the
+				 * moment, just treat this like loss of sync (which indeed it
+				 * might be!)
+				 */
+				handleSyncLoss(conn, id, msgLength);
+				break;
+			}
+			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 (pqGetInt(actual_result_len, 4, conn))
+					continue;
+				if (*actual_result_len != -1)
+				{
+					if (result_is_int)
+					{
+						if (pqGetInt(result_buf, *actual_result_len, conn))
+							continue;
+					}
+					else
+					{
+						if (pqGetnchar((char *) result_buf,
+									   *actual_result_len,
+									   conn))
+							continue;
+					}
+				}
+				/* correctly finished function result message */
+				status = PGRES_COMMAND_OK;
+				break;
+			case 'E':			/* error return */
+				if (pqGetErrorNotice3(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 (pqGetErrorNotice3(conn, false))
+					continue;
+				break;
+			case 'Z':			/* backend is ready for new query */
+				if (getReadyForQuery(conn))
+					continue;
+				/* consume the message and exit */
+				conn->inStart += 5 + msgLength;
+				/* if we saved a result object (probably an error), use it */
+				if (conn->result)
+					return pqPrepareAsyncResult(conn);
+				return PQmakeEmptyPGresult(conn, status);
+			case 'S':			/* parameter status */
+				if (getParameterStatus(conn))
+					continue;
+				break;
+			default:
+				/* The backend violates the protocol. */
+				appendPQExpBuffer(&conn->errorMessage,
+								  libpq_gettext("protocol error: id=0x%x\n"),
+								  id);
+				pqSaveErrorResult(conn);
+				/* trust the specified message length as what to skip */
+				conn->inStart += 5 + msgLength;
+				return pqPrepareAsyncResult(conn);
+		}
+
+		/* trace server-to-client message */
+		if (conn->Pfdebug)
+			pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
+
+		/* Completed this message, keep going */
+		/* trust the specified message length as what to skip */
+		conn->inStart += 5 + msgLength;
+		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 *
+pqBuildStartupPacket3(PGconn *conn, int *packetlen,
+					  const PQEnvironmentOption *options)
+{
+	char	   *startpacket;
+
+	*packetlen = build_startup_packet(conn, NULL, options);
+	startpacket = (char *) malloc(*packetlen);
+	if (!startpacket)
+		return NULL;
+	*packetlen = build_startup_packet(conn, startpacket, options);
+	return startpacket;
+}
+
+/*
+ * Build a startup packet given a filled-in PGconn structure.
+ *
+ * We need to figure out how much space is needed, then fill it in.
+ * To avoid duplicate logic, this routine is called twice: the first time
+ * (with packet == NULL) just counts the space needed, the second time
+ * (with packet == allocated space) fills it in.  Return value is the number
+ * of bytes used.
+ */
+static int
+build_startup_packet(const PGconn *conn, char *packet,
+					 const PQEnvironmentOption *options)
+{
+	int			packet_len = 0;
+	const PQEnvironmentOption *next_eo;
+	const char *val;
+
+	/* Protocol version comes first. */
+	if (packet)
+	{
+		ProtocolVersion pv = pg_hton32(conn->pversion);
+
+		memcpy(packet + packet_len, &pv, sizeof(ProtocolVersion));
+	}
+	packet_len += sizeof(ProtocolVersion);
+
+	/* Add user name, database name, options */
+
+#define ADD_STARTUP_OPTION(optname, optval) \
+	do { \
+		if (packet) \
+			strcpy(packet + packet_len, optname); \
+		packet_len += strlen(optname) + 1; \
+		if (packet) \
+			strcpy(packet + packet_len, optval); \
+		packet_len += strlen(optval) + 1; \
+	} while(0)
+
+	if (conn->pguser && conn->pguser[0])
+		ADD_STARTUP_OPTION("user", conn->pguser);
+	if (conn->dbName && conn->dbName[0])
+		ADD_STARTUP_OPTION("database", conn->dbName);
+	if (conn->replication && conn->replication[0])
+		ADD_STARTUP_OPTION("replication", conn->replication);
+	if (conn->pgoptions && conn->pgoptions[0])
+		ADD_STARTUP_OPTION("options", conn->pgoptions);
+	if (conn->send_appname)
+	{
+		/* Use appname if present, otherwise use fallback */
+		val = conn->appname ? conn->appname : conn->fbappname;
+		if (val && val[0])
+			ADD_STARTUP_OPTION("application_name", val);
+	}
+
+	if (conn->client_encoding_initial && conn->client_encoding_initial[0])
+		ADD_STARTUP_OPTION("client_encoding", conn->client_encoding_initial);
+
+	/* Add any environment-driven GUC settings needed */
+	for (next_eo = options; next_eo->envName; next_eo++)
+	{
+		if ((val = getenv(next_eo->envName)) != NULL)
+		{
+			if (pg_strcasecmp(val, "default") != 0)
+				ADD_STARTUP_OPTION(next_eo->pgName, val);
+		}
+	}
+
+	/* Add trailing terminator */
+	if (packet)
+		packet[packet_len] = '\0';
+	packet_len++;
+
+	return packet_len;
+}