Merge bitcoin/bitcoin#34158: torcontrol: Remove libevent usage

1401011 test: Add test for exceeding max line length in torcontrol (Fabian Jahr)
84c1f32 test: Add torcontrol coverage for PoW defense enablement (Fabian Jahr)
7dff9ec test: Add test for partial message handling in torcontrol (Fabian Jahr)
5693833 test: Add simple functional test for torcontrol (Fabian Jahr)
4117b92 fuzz: Improve torcontrol fuzz test (Fabian Jahr)
b1869e9 torcontrol: Move tor controller into node context (Fabian Jahr)
eae193e torcontrol: Remove libevent usage (Fabian Jahr)
8444efb refactor: Get rid of unnecessary newlines in logs (Fabian Jahr)
6bcb603 refactor: Modernize member variable names in torcontrol (Fabian Jahr)
a36591d refactor: Use constexpr in torcontrol where possible (Fabian Jahr)

Pull request description:

  This is part of the effort to remove the libevent dependency from our code base: bitcoin/bitcoin#31194

  The current approach tries to reuse existing code and follows roughly similar design decisions. It replaces the libevent-based async I/O with blocking I/O utilizing the existing `Sock` and `CThreadInterrupt`. The controller runs in a dedicated thread.

  There are some optional code modernizations thrown in made along the way (namings, constexpr etc.). These are not strictly necessary but make the end result with the new code more consistent.

ACKs for top commit:
  achow101:
    ACK 1401011
  janb84:
    re ACK 1401011
  pinheadmz:
    ACK 1401011

Tree-SHA512: 167f1d98a634524568cb1d723e7bdb7234bade2c5686586caf2accea58c3308f83a32e0705edc570d6db691ae578a91e474ae4773f126ec2e1619d3adf7df622

Author: achow101

src/init.cpp

@@ -276,7 +276,9 @@ void Interrupt(NodeContext& node)
     InterruptHTTPRPC();
     InterruptRPC();
     InterruptREST();
-    InterruptTorControl();
+    if (node.tor_controller) {
+        node.tor_controller->Interrupt();
+    }
     InterruptMapPort();
     if (node.connman)
         node.connman->Interrupt();
@@ -319,7 +321,10 @@ void Shutdown(NodeContext& node)
     if (node.peerman && node.validation_signals) node.validation_signals->UnregisterValidationInterface(node.peerman.get());
     if (node.connman) node.connman->Stop();
 
-    StopTorControl();
+    if (node.tor_controller) {
+        node.tor_controller->Join();
+        node.tor_controller.reset();
+    }
 
     if (node.background_init_thread.joinable()) node.background_init_thread.join();
     // After everything has been shut down, but before things get flushed, stop the
@@ -2187,7 +2192,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
                                     "for the automatically created Tor onion service."),
                                   onion_service_target.ToStringAddrPort()));
         }
-        StartTorControl(onion_service_target);
+        node.tor_controller = std::make_unique<TorController>(gArgs.GetArg("-torcontrol", DEFAULT_TOR_CONTROL), onion_service_target);
     }
 
     if (connOptions.bind_on_any) {

src/node/context.cpp

@@ -17,6 +17,7 @@
 #include <node/warnings.h>
 #include <policy/fees/block_policy_estimator.h>
 #include <scheduler.h>
+#include <torcontrol.h>
 #include <txmempool.h>
 #include <validation.h>
 #include <validationinterface.h>

src/node/context.h

@@ -25,6 +25,7 @@ class ChainstateManager;
 class ECC_Context;
 class NetGroupManager;
 class PeerManager;
+class TorController;
 namespace interfaces {
 class Chain;
 class ChainClient;
@@ -69,6 +70,7 @@ struct NodeContext {
     std::unique_ptr<const NetGroupManager> netgroupman;
     std::unique_ptr<CBlockPolicyEstimator> fee_estimator;
     std::unique_ptr<PeerManager> peerman;
+    std::unique_ptr<TorController> tor_controller;
     std::unique_ptr<ChainstateManager> chainman;
     std::unique_ptr<BanMan> banman;
     ArgsManager* args{nullptr}; // Currently a raw pointer because the memory is not managed by this struct

src/test/fuzz/torcontrol.cpp

@@ -12,28 +12,6 @@
 #include <string>
 #include <vector>
 
-class DummyTorControlConnection : public TorControlConnection
-{
-public:
-    DummyTorControlConnection() : TorControlConnection{nullptr}
-    {
-    }
-
-    bool Connect(const std::string&, const ConnectionCB&, const ConnectionCB&)
-    {
-        return true;
-    }
-
-    void Disconnect()
-    {
-    }
-
-    bool Command(const std::string&, const ReplyHandlerCB&)
-    {
-        return true;
-    }
-};
-
 void initialize_torcontrol()
 {
     static const auto testing_setup = MakeNoLogFileContext<>();
@@ -44,6 +22,9 @@ FUZZ_TARGET(torcontrol, .init = initialize_torcontrol)
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
 
     TorController tor_controller;
+    CThreadInterrupt interrupt;
+    TorControlConnection conn{interrupt};
+
     LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000) {
         TorControlReply tor_control_reply;
         CallOneOf(
@@ -61,26 +42,26 @@ FUZZ_TARGET(torcontrol, .init = initialize_torcontrol)
                 tor_control_reply.code = fuzzed_data_provider.ConsumeIntegral<int>();
             });
         tor_control_reply.lines = ConsumeRandomLengthStringVector(fuzzed_data_provider);
-        if (tor_control_reply.lines.empty()) {
-            break;
-        }
-        DummyTorControlConnection dummy_tor_control_connection;
+
         CallOneOf(
             fuzzed_data_provider,
             [&] {
-                tor_controller.add_onion_cb(dummy_tor_control_connection, tor_control_reply, /*pow_was_enabled=*/true);
+                tor_controller.add_onion_cb(conn, tor_control_reply, /*pow_was_enabled=*/true);
+            },
+            [&] {
+                tor_controller.add_onion_cb(conn, tor_control_reply, /*pow_was_enabled=*/false);
             },
             [&] {
-                tor_controller.add_onion_cb(dummy_tor_control_connection, tor_control_reply, /*pow_was_enabled=*/false);
+                tor_controller.auth_cb(conn, tor_control_reply);
             },
             [&] {
-                tor_controller.auth_cb(dummy_tor_control_connection, tor_control_reply);
+                tor_controller.authchallenge_cb(conn, tor_control_reply);
             },
             [&] {
-                tor_controller.authchallenge_cb(dummy_tor_control_connection, tor_control_reply);
+                tor_controller.protocolinfo_cb(conn, tor_control_reply);
             },
             [&] {
-                tor_controller.protocolinfo_cb(dummy_tor_control_connection, tor_control_reply);
+                tor_controller.get_socks_cb(conn, tor_control_reply);
             });
     }
 }