Front ported CORE-3554: Server crashes during prepare or throws incor…

…rect parsing error if the remotely passed SQL query is empty.

src/dsql/dsql.cpp

@@ -574,19 +574,6 @@ void DSQL_prepare(thread_db* tdbb,
 
 	dsql_req* request = NULL;
 
-	if (string && !length)
-	{
-		length = strlen(string);
-	}
-
-	if (!string || !length)
-	{
-		ERRD_post(Arg::Gds(isc_sqlerr) << Arg::Num(-104) <<
-				  // Unexpected end of command
-				  // CVC: Nothing will be line 1, column 1 for the user.
-				  Arg::Gds(isc_command_end_err2) << Arg::Num(1) << Arg::Num(1));
-	}
-
 	try
 	{
 		// Figure out which parser version to use
@@ -976,17 +963,6 @@ static void execute_immediate(thread_db* tdbb,
 {
 	SET_TDBB(tdbb);
 
-	if (!string)
-	{
-		ERRD_post(Arg::Gds(isc_sqlerr) << Arg::Num(-104) <<
-				  // Unexpected end of command
-				  // CVC: Nothing will be line 1, column 1 for the user.
-				  Arg::Gds(isc_command_end_err2) << Arg::Num(1) << Arg::Num(1));
-	}
-
-	if (length == 0)
-		length = strlen(string);
-
 	dsql_dbb* const database = init(tdbb, attachment);
 	dsql_req* request = NULL;
 
@@ -1874,17 +1850,21 @@ static dsql_req* prepareStatement(thread_db* tdbb, dsql_dbb* database, jrd_tra*
 				  Arg::Gds(isc_wish_list));
 	}
 
-	if (!string)
+	if (string && !string_length)
 	{
+		size_t sql_length = strlen(string);
+		if (sql_length > MAX_USHORT)
+			sql_length = MAX_USHORT;
+		string_length = static_cast<USHORT>(sql_length);
+	}
+
+	if (!string || !string_length) {
 		ERRD_post(Arg::Gds(isc_sqlerr) << Arg::Num(-104) <<
 				  // Unexpected end of command
 				  // CVC: Nothing will be line 1, column 1 for the user.
 				  Arg::Gds(isc_command_end_err2) << Arg::Num(1) << Arg::Num(1));
 	}
 
-	if (string_length == 0)
-		string_length = strlen(string);
-
 	// Get rid of the trailing ";" if there is one.
 
 	for (const TEXT* p = string + string_length; p-- > string;)

src/remote/client/interface.cpp

@@ -1812,6 +1812,14 @@ Firebird::ITransaction* Attachment::execute(IStatus* status, Firebird::ITransact
 			CHECK_HANDLE(transaction, isc_bad_trans_handle);
 		}
 
+		if (!length)
+		{
+			size_t sql_length = strlen(string);
+			if (sql_length > MAX_USHORT)
+				sql_length = MAX_USHORT;
+			length = static_cast<USHORT>(sql_length);
+		}
+
 		if (dialect > 10)
 		{
 			// dimitr: adjust dialect received after
@@ -1900,7 +1908,7 @@ Firebird::ITransaction* Attachment::execute(IStatus* status, Firebird::ITransact
 		P_SQLST* ex_now = &packet->p_sqlst;
 		ex_now->p_sqlst_transaction = transaction ? transaction->rtr_id : 0;
 		ex_now->p_sqlst_SQL_dialect = dialect;
-		ex_now->p_sqlst_SQL_str.cstr_length = length ? length : strlen(string);
+		ex_now->p_sqlst_SQL_str.cstr_length = length;
 		ex_now->p_sqlst_SQL_str.cstr_address = reinterpret_cast<const UCHAR*>(string);
 		ex_now->p_sqlst_items.cstr_length = 0;
 		ex_now->p_sqlst_buffer_length = 0;
@@ -2453,6 +2461,14 @@ void Statement::prepare(IStatus* status, Firebird::ITransaction* apiTra,
 			CHECK_HANDLE(transaction, isc_bad_trans_handle);
 		}
 
+		if (!stmtLength)
+		{
+			size_t sql_length = strlen(sqlStmt);
+			if (sql_length > MAX_USHORT)
+				sql_length = MAX_USHORT;
+			stmtLength = static_cast<USHORT>(sql_length);
+		}
+
 		if (dialect > 10)
 		{
 			// dimitr: adjust dialect received after
@@ -2494,7 +2510,7 @@ void Statement::prepare(IStatus* status, Firebird::ITransaction* apiTra,
 		prepare->p_sqlst_transaction = transaction ? transaction->rtr_id : 0;
 		prepare->p_sqlst_statement = statement->rsr_id;
 		prepare->p_sqlst_SQL_dialect = dialect;
-		prepare->p_sqlst_SQL_str.cstr_length = stmtLength ? stmtLength : strlen(sqlStmt);
+		prepare->p_sqlst_SQL_str.cstr_length = stmtLength;
 		prepare->p_sqlst_SQL_str.cstr_address = reinterpret_cast<const UCHAR*>(sqlStmt);
 		prepare->p_sqlst_items.cstr_length = items.getCount();
 		prepare->p_sqlst_items.cstr_address = items.begin();

src/remote/protocol.cpp

@@ -853,7 +853,14 @@ static bool alloc_cstring(XDR* xdrs, CSTRING* cstring)
  **************************************/
 
 	if (!cstring->cstr_length)
+	{
+		if (cstring->cstr_allocated)
+			*cstring->cstr_address = '\0';
+		else
+			cstring->cstr_address = NULL;
+
 		return true;
+	}
 
 	if (cstring->cstr_length > cstring->cstr_allocated && cstring->cstr_allocated)
 	{