/*
 * 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)
			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.  NOTICE is definitely possible, and ParameterStatus
		 * could probably be made to happen.)  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;
			default:			/* treat as end of copy */
				return -1;
		}

		/* Drop the processed message and loop around for another */
		conn->inStart = conn->inCursor;
	}
}
/*
 * getCopyStart - process CopyInResponse or CopyOutResponse 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;
}
Exemplo n.º 4
0
/*
 * 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;
	}
}
Exemplo n.º 5
0
/*
 * 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);
}
/*
 * 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;
	PQExpBufferData workBuf;
	char		id;
	const char *val;
	const char *querytext = NULL;
	int			querypos = 0;

	/*
	 * 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.
	 */
	res = PQmakeEmptyPGresult(conn, PGRES_EMPTY_QUERY);
	if (!res)
		goto fail;
	res->resultStatus = isError ? PGRES_FATAL_ERROR : PGRES_NONFATAL_ERROR;

	/*
	 * Read the fields and save into res.
	 */
	for (;;)
	{
		if (pqGetc(&id, conn))
			goto fail;
		if (id == '\0')
			break;				/* terminator found */
		if (pqGets(&workBuf, conn))
			goto fail;
		pqSaveMessageField(res, id, workBuf.data);
	}

	/*
	 * Now build the "overall" error message for PQresultErrorMessage.
	 */
	resetPQExpBuffer(&workBuf);
	val = PQresultErrorField(res, PG_DIAG_SEVERITY);
	if (val)
		appendPQExpBuffer(&workBuf, "%s:  ", val);
	if (conn->verbosity == PQERRORS_VERBOSE)
	{
		val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
		if (val)
			appendPQExpBuffer(&workBuf, "%s: ", val);
	}
	val = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
	if (val)
		appendPQExpBufferStr(&workBuf, val);
	val = PQresultErrorField(res, PG_DIAG_STATEMENT_POSITION);
	if (val)
	{
		if (conn->verbosity != PQERRORS_TERSE && conn->last_query != NULL)
		{
			/* emit position as a syntax cursor display */
			querytext = conn->last_query;
			querypos = atoi(val);
		}
		else
		{
			/* emit position as text addition to primary message */
			/* translator: %s represents a digit string */
			appendPQExpBuffer(&workBuf, libpq_gettext(" at character %s"),
							  val);
		}
	}
	else
	{
		val = PQresultErrorField(res, PG_DIAG_INTERNAL_POSITION);
		if (val)
		{
			querytext = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
			if (conn->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(&workBuf, libpq_gettext(" at character %s"),
								  val);
			}
		}
	}
	appendPQExpBufferChar(&workBuf, '\n');
	if (conn->verbosity != PQERRORS_TERSE)
	{
		if (querytext && querypos > 0)
			reportErrorPosition(&workBuf, querytext, querypos,
								conn->client_encoding);
		val = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
		if (val)
			appendPQExpBuffer(&workBuf, libpq_gettext("DETAIL:  %s\n"), val);
		val = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
		if (val)
			appendPQExpBuffer(&workBuf, libpq_gettext("HINT:  %s\n"), val);
		val = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
		if (val)
			appendPQExpBuffer(&workBuf, libpq_gettext("QUERY:  %s\n"), val);
		val = PQresultErrorField(res, PG_DIAG_CONTEXT);
		if (val)
			appendPQExpBuffer(&workBuf, libpq_gettext("CONTEXT:  %s\n"), val);
	}
	if (conn->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(&workBuf, libpq_gettext("LOCATION:  "));
			if (val)
				appendPQExpBuffer(&workBuf, libpq_gettext("%s, "), val);
			if (valf && vall)	/* unlikely we'd have just one */
				appendPQExpBuffer(&workBuf, libpq_gettext("%s:%s"),
								  valf, vall);
			appendPQExpBufferChar(&workBuf, '\n');
		}
	}

	/*
	 * Either save error as current async result, or just emit the notice.
	 */
	if (isError)
	{
		res->errMsg = pqResultStrdup(res, workBuf.data);
		if (!res->errMsg)
			goto fail;
		pqClearAsyncResult(conn);
		conn->result = res;
		resetPQExpBuffer(&conn->errorMessage);
		appendPQExpBufferStr(&conn->errorMessage, workBuf.data);
	}
	else
	{
		/* We can cheat a little here and not copy the message. */
		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;
}
/*
 * 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 + 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 displayed 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
			{
				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)
							return;
					}
					strncpy(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':		/* backend is ready for new query */
					if (getReadyForQuery(conn))
						return;
					conn->asyncStatus = PGASYNC_IDLE;
					break;
				case 'I':		/* empty query */
					if (conn->result == NULL)
					{
						conn->result = PQmakeEmptyPGresult(conn,
														   PGRES_EMPTY_QUERY);
						if (!conn->result)
							return;
					}
					conn->asyncStatus = PGASYNC_READY;
					break;
				case '1':		/* Parse Complete */
					/* If we're doing PQprepare, we're done; else ignore */
					if (conn->queryclass == PGQUERY_PREPARE)
					{
						if (conn->result == NULL)
						{
							conn->result = PQmakeEmptyPGresult(conn,
														   PGRES_COMMAND_OK);
							if (!conn->result)
								return;
						}
						conn->asyncStatus = PGASYNC_READY;
					}
					break;
				case '2':		/* Bind Complete */
				case '3':		/* Close Complete */
					/* Nothing to do for these message types */
					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->queryclass == PGQUERY_DESCRIBE)
					{
						/* First 'T' in a query sequence */
						if (getRowDescriptions(conn))
							return;

						/*
						 * If we're doing a Describe, we're ready to pass the
						 * result back to the client.
						 */
						if (conn->queryclass == PGQUERY_DESCRIBE)
							conn->asyncStatus = PGASYNC_READY;
					}
					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. Set up a COMMAND_OK
					 * result, instead of TUPLES_OK.
					 */
					if (conn->result == NULL)
						conn->result = PQmakeEmptyPGresult(conn,
														   PGRES_COMMAND_OK);

					/*
					 * If we're doing a Describe, we're ready to pass the
					 * result back to the client.
					 */
					if (conn->queryclass == PGQUERY_DESCRIBE)
						conn->asyncStatus = PGASYNC_READY;
					break;
				case 't':		/* Parameter Description */
					if (getParamDescriptions(conn))
						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 */
						printfPQExpBuffer(&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 '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:
					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);
					/* 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)
		{
			/* Normal case: parsing agrees with specified length */
			conn->inStart = conn->inCursor;
		}
		else
		{
			/* Trouble --- report it */
			printfPQExpBuffer(&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;
		}
	}
}
/*
 * 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;

	/* PQfn already validated connection state */

	if (pqPutMsgStart('F', false, 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 */
	{
		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].len == -1)
			continue;			/* it's NULL */

		if (args[i].isint)
		{
			if (pqPutInt(args[i].u.integer, args[i].len, conn))
			{
				pqHandleSendFailure(conn);
				return NULL;
			}
		}
		else
		{
			if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
			{
				pqHandleSendFailure(conn);
				return NULL;
			}
		}
	}

	if (pqPutInt(1, 2, conn) < 0)		/* result format code: BINARY */
	{
		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.
		 */
		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 + 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. */
				printfPQExpBuffer(&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);
		}
		/* 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);
}
Exemplo n.º 9
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;
			default:			/* treat as end of copy */
				return -1;
		}

		/* Drop the processed message and loop around for another */
		conn->inStart = conn->inCursor;
	}
}