Remove pointer cast in CRPCTable::dumpArgMap

CRPCTable::dumpArgMap currently works by casting RPC command unique_id
integer field to a function pointer, and then calling the function. The
unique_id field wasn't supposed to be used this way (it's meant to be
used to detect RPC aliases), and this code segfaults in the rpc_help.py
test in multiprocess PR https://github.com/bitcoin/bitcoin/pull/10102
because wallet RPC functions aren't directly accessible from the node
process.

Fix this by adding a new GET_ARGS request mode to retrieve argument
information similar to the way the GET_HELP mode retrieves help
information.

1 files changed, 10 insertions, 5 deletions

diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index 66134a77b2..39938f4eb9 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -149,7 +149,7 @@ static RPCHelpMan help()
     }
     if (strCommand == "dump_all_command_conversions") {
         // Used for testing only, undocumented
-        return tableRPC.dumpArgMap();
+        return tableRPC.dumpArgMap(jsonRequest);
     }
 
     return tableRPC.help(strCommand, jsonRequest);
@@ -492,13 +492,18 @@ std::vector<std::string> CRPCTable::listCommands() const
     return commandList;
 }
 
-UniValue CRPCTable::dumpArgMap() const
+UniValue CRPCTable::dumpArgMap(const JSONRPCRequest& args_request) const
 {
+    JSONRPCRequest request(args_request);
+    request.mode = JSONRPCRequest::GET_ARGS;
+
     UniValue ret{UniValue::VARR};
     for (const auto& cmd : mapCommands) {
-        for (const auto& c : cmd.second) {
-            const auto help = RpcMethodFnType(c->unique_id)();
-            help.AppendArgMap(ret);
+        UniValue result;
+        if (ExecuteCommands(cmd.second, request, result)) {
+            for (const auto& values : result.getValues()) {
+                ret.push_back(values);
+            }
         }
     }
     return ret;