multiprocess: Add unit tests for connect, serve, and listen functions

src/ipc/capnp/protocol.cpp

@@ -61,11 +61,12 @@ public:
         }
         mp::ListenConnections<messages::Init>(*m_loop, listen_fd, init);
     }
-    void serve(int fd, const char* exe_name, interfaces::Init& init) override
+    void serve(int fd, const char* exe_name, interfaces::Init& init, const std::function<void()>& ready_fn = {}) override
     {
         assert(!m_loop);
         mp::g_thread_context.thread_name = mp::ThreadName(exe_name);
         m_loop.emplace(exe_name, &IpcLogFn, &m_context);
+        if (ready_fn) ready_fn();
         mp::ServeStream<messages::Init>(*m_loop, fd, init);
         m_loop->loop();
         m_loop.reset();

src/ipc/protocol.h

@@ -50,7 +50,13 @@ public:
     //! created by them. This isn't really a problem because serve() is only
     //! called by spawned child processes that call it immediately to
     //! communicate back with parent processes.
-    virtual void serve(int fd, const char* exe_name, interfaces::Init& init) = 0;
+    //
+    //! The optional `ready_fn` callback will be called after the event loop is
+    //! created but before it is started. This can be useful in tests to trigger
+    //! client connections from another thread as soon as the event loop is
+    //! available, but should not be neccessary in normal code which starts
+    //! clients and servers independently.
+    virtual void serve(int fd, const char* exe_name, interfaces::Init& init, const std::function<void()>& ready_fn = {}) = 0;
 
     //! Add cleanup callback to interface that will run when the interface is
     //! deleted.

src/test/CMakeLists.txt

@@ -177,7 +177,7 @@ if(WITH_MULTIPROCESS)
     PRIVATE
       ipc_tests.cpp
   )
-  target_link_libraries(test_bitcoin bitcoin_ipc_test)
+  target_link_libraries(test_bitcoin bitcoin_ipc_test bitcoin_ipc)
 endif()
 
 function(add_boost_test source_file)

src/test/ipc_test.cpp

@@ -2,19 +2,46 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <interfaces/init.h>
+#include <ipc/capnp/protocol.h>
+#include <ipc/process.h>
+#include <ipc/protocol.h>
 #include <logging.h>
 #include <mp/proxy-types.h>
 #include <test/ipc_test.capnp.h>
 #include <test/ipc_test.capnp.proxy.h>
 #include <test/ipc_test.h>
+#include <tinyformat.h>
 
 #include <future>
+#include <thread>
 #include <kj/common.h>
 #include <kj/memory.h>
 #include <kj/test.h>
+#include <stdexcept>
 
 #include <boost/test/unit_test.hpp>
 
+//! Remote init class.
+class TestInit : public interfaces::Init
+{
+public:
+    std::unique_ptr<interfaces::Echo> makeEcho() override { return interfaces::MakeEcho(); }
+};
+
+//! Generate a temporary path with temp_directory_path and mkstemp
+static std::string TempPath(std::string_view pattern)
+{
+    std::string temp{fs::PathToString(fs::path{fs::temp_directory_path()} / fs::PathFromString(std::string{pattern}))};
+    temp.push_back('\0');
+    int fd{mkstemp(temp.data())};
+    BOOST_CHECK_GE(fd, 0);
+    BOOST_CHECK_EQUAL(close(fd), 0);
+    temp.resize(temp.size() - 1);
+    fs::remove(fs::PathFromString(temp));
+    return temp;
+}
+
 //! Unit test that tests execution of IPC calls without actually creating a
 //! separate process. This test is primarily intended to verify behavior of type
 //! conversion code that converts C++ objects to Cap'n Proto messages and vice
@@ -23,13 +50,13 @@
 //! The test creates a thread which creates a FooImplementation object (defined
 //! in ipc_test.h) and a two-way pipe accepting IPC requests which call methods
 //! on the object through FooInterface (defined in ipc_test.capnp).
-void IpcTest()
+void IpcPipeTest()
 {
     // Setup: create FooImplemention object and listen for FooInterface requests
     std::promise<std::unique_ptr<mp::ProxyClient<gen::FooInterface>>> foo_promise;
     std::function<void()> disconnect_client;
     std::thread thread([&]() {
-        mp::EventLoop loop("IpcTest", [](bool raise, const std::string& log) { LogPrintf("LOG%i: %s\n", raise, log); });
+        mp::EventLoop loop("IpcPipeTest", [](bool raise, const std::string& log) { LogPrintf("LOG%i: %s\n", raise, log); });
         auto pipe = loop.m_io_context.provider->newTwoWayPipe();
 
         auto connection_client = std::make_unique<mp::Connection>(loop, kj::mv(pipe.ends[0]));
@@ -65,3 +92,71 @@ void IpcTest()
     disconnect_client();
     thread.join();
 }
+
+//! Test ipc::Protocol connect() and serve() methods connecting over a socketpair.
+void IpcSocketPairTest()
+{
+    int fds[2];
+    BOOST_CHECK_EQUAL(socketpair(AF_UNIX, SOCK_STREAM, 0, fds), 0);
+    std::unique_ptr<interfaces::Init> init{std::make_unique<TestInit>()};
+    std::unique_ptr<ipc::Protocol> protocol{ipc::capnp::MakeCapnpProtocol()};
+    std::promise<void> promise;
+    std::thread thread([&]() {
+        protocol->serve(fds[0], "test-serve", *init, [&] { promise.set_value(); });
+    });
+    promise.get_future().wait();
+    std::unique_ptr<interfaces::Init> remote_init{protocol->connect(fds[1], "test-connect")};
+    std::unique_ptr<interfaces::Echo> remote_echo{remote_init->makeEcho()};
+    BOOST_CHECK_EQUAL(remote_echo->echo("echo test"), "echo test");
+    remote_echo.reset();
+    remote_init.reset();
+    thread.join();
+}
+
+//! Test ipc::Process bind() and connect() methods connecting over a unix socket.
+void IpcSocketTest(const fs::path& datadir)
+{
+    std::unique_ptr<interfaces::Init> init{std::make_unique<TestInit>()};
+    std::unique_ptr<ipc::Protocol> protocol{ipc::capnp::MakeCapnpProtocol()};
+    std::unique_ptr<ipc::Process> process{ipc::MakeProcess()};
+
+    std::string invalid_bind{"invalid:"};
+    BOOST_CHECK_THROW(process->bind(datadir, "test_bitcoin", invalid_bind), std::invalid_argument);
+    BOOST_CHECK_THROW(process->connect(datadir, "test_bitcoin", invalid_bind), std::invalid_argument);
+
+    auto bind_and_listen{[&](const std::string& bind_address) {
+        std::string address{bind_address};
+        int serve_fd = process->bind(datadir, "test_bitcoin", address);
+        BOOST_CHECK_GE(serve_fd, 0);
+        BOOST_CHECK_EQUAL(address, bind_address);
+        protocol->listen(serve_fd, "test-serve", *init);
+    }};
+
+    auto connect_and_test{[&](const std::string& connect_address) {
+        std::string address{connect_address};
+        int connect_fd{process->connect(datadir, "test_bitcoin", address)};
+        BOOST_CHECK_EQUAL(address, connect_address);
+        std::unique_ptr<interfaces::Init> remote_init{protocol->connect(connect_fd, "test-connect")};
+        std::unique_ptr<interfaces::Echo> remote_echo{remote_init->makeEcho()};
+        BOOST_CHECK_EQUAL(remote_echo->echo("echo test"), "echo test");
+    }};
+
+    // Need to specify explicit socket addresses outside the data directory, because the data
+    // directory path is so long that the default socket address and any other
+    // addresses in the data directory would fail with errors like:
+    //   Address 'unix' path '"/tmp/test_common_Bitcoin Core/ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff/test_bitcoin.sock"' exceeded maximum socket path length
+    std::vector<std::string> addresses{
+        strprintf("unix:%s", TempPath("bitcoin_sock0_XXXXXX")),
+        strprintf("unix:%s", TempPath("bitcoin_sock1_XXXXXX")),
+    };
+
+    // Bind and listen on multiple addresses
+    for (const auto& address : addresses) {
+        bind_and_listen(address);
+    }
+
+    // Connect and test each address multiple times.
+    for (int i : {0, 1, 0, 0, 1}) {
+        connect_and_test(addresses[i]);
+    }
+}

src/test/ipc_test.h

@@ -7,6 +7,7 @@
 
 #include <primitives/transaction.h>
 #include <univalue.h>
+#include <util/fs.h>
 
 class FooImplementation
 {
@@ -16,6 +17,8 @@ public:
     UniValue passUniValue(UniValue v) { return v; }
 };
 
-void IpcTest();
+void IpcPipeTest();
+void IpcSocketPairTest();
+void IpcSocketTest(const fs::path& datadir);
 
 #endif // BITCOIN_TEST_IPC_TEST_H

src/test/ipc_tests.cpp

@@ -2,12 +2,41 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <ipc/process.h>
 #include <test/ipc_test.h>
+
+#include <test/util/setup_common.h>
 #include <boost/test/unit_test.hpp>
 
-BOOST_AUTO_TEST_SUITE(ipc_tests)
+BOOST_FIXTURE_TEST_SUITE(ipc_tests, BasicTestingSetup)
 BOOST_AUTO_TEST_CASE(ipc_tests)
 {
-    IpcTest();
+    IpcPipeTest();
+    IpcSocketPairTest();
+    IpcSocketTest(m_args.GetDataDirNet());
 }
+
+// Test address parsing.
+BOOST_AUTO_TEST_CASE(parse_address_test)
+{
+    std::unique_ptr<ipc::Process> process{ipc::MakeProcess()};
+    fs::path datadir{"/var/empty/notexist"};
+    auto check_notexist{[](const std::system_error& e) { return e.code() == std::errc::no_such_file_or_directory; }};
+    auto check_address{[&](std::string address, std::string expect_address, std::string expect_error) {
+        if (expect_error.empty()) {
+            BOOST_CHECK_EXCEPTION(process->connect(datadir, "test_bitcoin", address), std::system_error, check_notexist);
+        } else {
+            BOOST_CHECK_EXCEPTION(process->connect(datadir, "test_bitcoin", address), std::invalid_argument, HasReason(expect_error));
+        }
+        BOOST_CHECK_EQUAL(address, expect_address);
+    }};
+    check_address("unix", "unix:/var/empty/notexist/test_bitcoin.sock", "");
+    check_address("unix:", "unix:/var/empty/notexist/test_bitcoin.sock", "");
+    check_address("unix:path.sock", "unix:/var/empty/notexist/path.sock", "");
+    check_address("unix:0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.sock",
+                  "unix:/var/empty/notexist/0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.sock",
+                  "Unix address path \"/var/empty/notexist/0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.sock\" exceeded maximum socket path length");
+    check_address("invalid", "invalid", "Unrecognized address 'invalid'");
+}
+
 BOOST_AUTO_TEST_SUITE_END()