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diff --git a/src/seastar/include/seastar/util/program-options.hh b/src/seastar/include/seastar/util/program-options.hh
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+++ b/src/seastar/include/seastar/util/program-options.hh
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+/*
+ * This file is open source software, licensed to you under the terms
+ * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
+ * distributed with this work for additional information regarding copyright
+ * ownership.  You may not use this file except in compliance with the License.
+ *
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Copyright (C) 2017 ScyllaDB
+ */
+
+#pragma once
+
+#include <seastar/core/sstring.hh>
+
+#include <boost/any.hpp>
+#include <boost/program_options.hpp>
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace seastar {
+
+namespace program_options {
+
+///
+/// \brief Wrapper for command-line options with arbitrary string associations.
+///
+/// This type, to be used with Boost.Program_options, will result in an option that stores an arbitrary number of
+/// string associations.
+///
+/// Values are specified in the form "key0=value0:[key1=value1:...]". Options of this type can be specified multiple
+/// times, and the values will be merged (with the last-provided value for a key taking precedence).
+///
+/// \note We need a distinct type (rather than a simple type alias) for overload resolution in the implementation, but
+/// advertizing our inheritance of \c std::unordered_map would introduce the possibility of memory leaks since STL
+/// containers do not declare virtual destructors.
+///
+class string_map final : private std::unordered_map<sstring, sstring> {
+private:
+    using base = std::unordered_map<sstring, sstring>;
+public:
+    using base::value_type;
+    using base::key_type;
+    using base::mapped_type;
+
+    using base::base;
+    using base::at;
+    using base::find;
+    using base::count;
+    using base::emplace;
+    using base::clear;
+    using base::operator[];
+    using base::begin;
+    using base::end;
+
+    friend bool operator==(const string_map&, const string_map&);
+    friend bool operator!=(const string_map&, const string_map&);
+};
+
+inline bool operator==(const string_map& lhs, const string_map& rhs) {
+    return static_cast<const string_map::base&>(lhs) == static_cast<const string_map::base&>(rhs);
+}
+
+inline bool operator!=(const string_map& lhs, const string_map& rhs) {
+    return !(lhs == rhs);
+}
+
+///
+/// \brief Query the value of a key in a \c string_map, or a default value if the key doesn't exist.
+///
+sstring get_or_default(const string_map&, const sstring& key, const sstring& def = sstring());
+
+std::istream& operator>>(std::istream& is, string_map&);
+std::ostream& operator<<(std::ostream& os, const string_map&);
+
+/// \cond internal
+
+//
+// Required implementation hook for Boost.Program_options.
+//
+void validate(boost::any& out, const std::vector<std::string>& in, string_map*, int);
+
+/// \endcond
+
+}
+
+}