multiprocess: Add Ipc interface implementation

src/ipc/interfaces.cpp

@@ -0,0 +1,77 @@
+// Copyright (c) 2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <fs.h>
+#include <interfaces/init.h>
+#include <interfaces/ipc.h>
+#include <ipc/capnp/protocol.h>
+#include <ipc/process.h>
+#include <ipc/protocol.h>
+#include <logging.h>
+#include <tinyformat.h>
+#include <util/system.h>
+
+#include <functional>
+#include <memory>
+#include <stdexcept>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <string>
+#include <unistd.h>
+#include <utility>
+#include <vector>
+
+namespace ipc {
+namespace {
+class IpcImpl : public interfaces::Ipc
+{
+public:
+    IpcImpl(const char* exe_name, const char* process_argv0, interfaces::Init& init)
+        : m_exe_name(exe_name), m_process_argv0(process_argv0), m_init(init),
+          m_protocol(ipc::capnp::MakeCapnpProtocol()), m_process(ipc::MakeProcess())
+    {
+    }
+    std::unique_ptr<interfaces::Init> spawnProcess(const char* new_exe_name) override
+    {
+        int pid;
+        int fd = m_process->spawn(new_exe_name, m_process_argv0, pid);
+        LogPrint(::BCLog::IPC, "Process %s pid %i launched\n", new_exe_name, pid);
+        auto init = m_protocol->connect(fd, m_exe_name);
+        Ipc::addCleanup(*init, [this, new_exe_name, pid] {
+            int status = m_process->waitSpawned(pid);
+            LogPrint(::BCLog::IPC, "Process %s pid %i exited with status %i\n", new_exe_name, pid, status);
+        });
+        return init;
+    }
+    bool startSpawnedProcess(int argc, char* argv[], int& exit_status) override
+    {
+        exit_status = EXIT_FAILURE;
+        int32_t fd = -1;
+        if (!m_process->checkSpawned(argc, argv, fd)) {
+            return false;
+        }
+        m_protocol->serve(fd, m_exe_name, m_init);
+        exit_status = EXIT_SUCCESS;
+        return true;
+    }
+    void addCleanup(std::type_index type, void* iface, std::function<void()> cleanup) override
+    {
+        m_protocol->addCleanup(type, iface, std::move(cleanup));
+    }
+    const char* m_exe_name;
+    const char* m_process_argv0;
+    interfaces::Init& m_init;
+    std::unique_ptr<Protocol> m_protocol;
+    std::unique_ptr<Process> m_process;
+};
+} // namespace
+} // namespace ipc
+
+namespace interfaces {
+std::unique_ptr<Ipc> MakeIpc(const char* exe_name, const char* process_argv0, Init& init)
+{
+    return std::make_unique<ipc::IpcImpl>(exe_name, process_argv0, init);
+}
+} // namespace interfaces