1 files changed, 38 insertions, 12 deletions

diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index e9987d73be..44d7e2676b 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -1,5 +1,5 @@
 // Copyright (c) 2010 Satoshi Nakamoto
-// Copyright (c) 2009-2021 The Bitcoin Core developers
+// Copyright (c) 2009-2022 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -21,8 +21,6 @@
 #include <mutex>
 #include <unordered_map>
 
-using SteadyClock = std::chrono::steady_clock;
-
 static GlobalMutex g_rpc_warmup_mutex;
 static std::atomic<bool> g_rpc_running{false};
 static bool fRPCInWarmup GUARDED_BY(g_rpc_warmup_mutex) = true;
@@ -105,7 +103,7 @@ std::string CRPCTable::help(const std::string& strCommand, const JSONRPCRequest&
         {
             UniValue unused_result;
             if (setDone.insert(pcmd->unique_id).second)
-                pcmd->actor(jreq, unused_result, true /* last_handler */);
+                pcmd->actor(jreq, unused_result, /*last_handler=*/true);
         }
         catch (const std::exception& e)
         {
@@ -170,7 +168,7 @@ static RPCHelpMan stop()
     // to the client (intended for testing)
                 "\nRequest a graceful shutdown of " PACKAGE_NAME ".",
                 {
-                    {"wait", RPCArg::Type::NUM, RPCArg::Optional::OMITTED_NAMED_ARG, "how long to wait in ms", "", {}, /*hidden=*/true},
+                    {"wait", RPCArg::Type::NUM, RPCArg::Optional::OMITTED, "how long to wait in ms", RPCArgOptions{.hidden=true}},
                 },
                 RPCResult{RPCResult::Type::STR, "", "A string with the content '" + RESULT + "'"},
                 RPCExamples{""},
@@ -401,10 +399,21 @@ static inline JSONRPCRequest transformNamedArguments(const JSONRPCRequest& in, c
     const std::vector<UniValue>& values = in.params.getValues();
     std::unordered_map<std::string, const UniValue*> argsIn;
     for (size_t i=0; i<keys.size(); ++i) {
-        argsIn[keys[i]] = &values[i];
+        auto [_, inserted] = argsIn.emplace(keys[i], &values[i]);
+        if (!inserted) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Parameter " + keys[i] + " specified multiple times");
+        }
     }
-    // Process expected parameters.
+    // Process expected parameters. If any parameters were left unspecified in
+    // the request before a parameter that was specified, null values need to be
+    // inserted at the unspecifed parameter positions, and the "hole" variable
+    // below tracks the number of null values that need to be inserted.
+    // The "initial_hole_size" variable stores the size of the initial hole,
+    // i.e. how many initial positional arguments were left unspecified. This is
+    // used after the for-loop to add initial positional arguments from the
+    // "args" parameter, if present.
     int hole = 0;
+    int initial_hole_size = 0;
     for (const std::string &argNamePattern: argNames) {
         std::vector<std::string> vargNames = SplitString(argNamePattern, '|');
         auto fr = argsIn.end();
@@ -426,6 +435,24 @@ static inline JSONRPCRequest transformNamedArguments(const JSONRPCRequest& in, c
             argsIn.erase(fr);
         } else {
             hole += 1;
+            if (out.params.empty()) initial_hole_size = hole;
+        }
+    }
+    // If leftover "args" param was found, use it as a source of positional
+    // arguments and add named arguments after. This is a convenience for
+    // clients that want to pass a combination of named and positional
+    // arguments as described in doc/JSON-RPC-interface.md#parameter-passing
+    auto positional_args{argsIn.extract("args")};
+    if (positional_args && positional_args.mapped()->isArray()) {
+        const bool has_named_arguments{initial_hole_size < (int)argNames.size()};
+        if (initial_hole_size < (int)positional_args.mapped()->size() && has_named_arguments) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Parameter " + argNames[initial_hole_size] + " specified twice both as positional and named argument");
+        }
+        // Assign positional_args to out.params and append named_args after.
+        UniValue named_args{std::move(out.params)};
+        out.params = *positional_args.mapped();
+        for (size_t i{out.params.size()}; i < named_args.size(); ++i) {
+            out.params.push_back(named_args[i]);
         }
     }
     // If there are still arguments in the argsIn map, this is an error.
@@ -468,8 +495,7 @@ UniValue CRPCTable::execute(const JSONRPCRequest &request) const
 
 static bool ExecuteCommand(const CRPCCommand& command, const JSONRPCRequest& request, UniValue& result, bool last_handler)
 {
-    try
-    {
+    try {
         RPCCommandExecution execution(request.strMethod);
         // Execute, convert arguments to array if necessary
         if (request.params.isObject()) {
@@ -477,9 +503,9 @@ static bool ExecuteCommand(const CRPCCommand& command, const JSONRPCRequest& req
         } else {
             return command.actor(request, result, last_handler);
         }
-    }
-    catch (const std::exception& e)
-    {
+    } catch (const UniValue::type_error& e) {
+        throw JSONRPCError(RPC_TYPE_ERROR, e.what());
+    } catch (const std::exception& e) {
         throw JSONRPCError(RPC_MISC_ERROR, e.what());
     }
 }