ipc # Multiprocess bitcoin

Multiprocess bitcoin

This change only affects bitcoin-node, bitcoin-wallet, and bitcoin-gui
executables, which aren't built by default (they can be enabled with the
--enable-multiprocess autoconf option). Normal bitcoind and bitcoin-qt build
outputs are unaffected by this change.

After this change, bitcoin-gui will spawn a bitcoin-node process, and
bitcoin-node will spawn a bitcoin-wallet process. The processes communicate
across socket pairs so gui, node, and wallet functionality is segregated into
respective processes. The IPC calls can be seen running with -debug=ipc.  See
doc/multiprocess.md for details.

Work in progress, many improvements and cleanups are needed (see FIXMEs)

Author: ryanofsky

build_msvc/bitcoin-qt/bitcoin-qt.vcxproj

@@ -9,6 +9,7 @@
   </PropertyGroup>
   <ItemGroup>
     <ClCompile Include="..\..\src\qt\main.cpp" />
+    <ClCompile Include="..\..\src\init\bitcoin-qt.cpp" />
     <ResourceCompile Include="..\..\src\qt\res\bitcoin-qt-res.rc" />
   </ItemGroup>
   <ItemGroup>

build_msvc/bitcoin-wallet/bitcoin-wallet.vcxproj

@@ -10,6 +10,9 @@
   </PropertyGroup>
   <ItemGroup>
     <ClCompile Include="..\..\src\bitcoin-wallet.cpp" />
+    <ClCompile Include="..\..\src\init\bitcoin-wallet.cpp">
+      <ObjectFileName>$(IntDir)init_bitcoin-wallet.obj</ObjectFileName>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\libbitcoinconsensus\libbitcoinconsensus.vcxproj">

build_msvc/test_bitcoin-qt/test_bitcoin-qt.vcxproj

@@ -8,6 +8,7 @@
     <OutDir>$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
   </PropertyGroup>
   <ItemGroup>
+    <ClCompile Include="..\..\src\init\bitcoin-qt.cpp" />
     <ClCompile Include="..\..\src\test\util\setup_common.cpp" />
     <ClCompile Include="..\..\src\qt\test\addressbooktests.cpp" />
     <ClCompile Include="..\..\src\qt\test\apptests.cpp" />

contrib/devtools/circular-dependencies.py

@@ -16,7 +16,7 @@
 # define functions and variables declared in corresponding .h files is
 # incorrect.
 HEADER_MODULE_PATHS = [
-    'interfaces/'
+    'ipc/'
 ]
 
 def module_name(path):

doc/multiprocess.md

@@ -2,12 +2,10 @@
 
 On unix systems, the `--enable-multiprocess` build option can be passed to `./configure` to build new `bitcoin-node`, `bitcoin-wallet`, and `bitcoin-gui` executables alongside existing `bitcoind` and `bitcoin-qt` executables.
 
-`bitcoin-node` is a drop-in replacement for `bitcoind`, and `bitcoin-gui` is a drop-in replacement for `bitcoin-qt`, and there are no differences in use or external behavior between the new and old executables. But internally (after [#10102](https://github.com/bitcoin/bitcoin/pull/10102)), `bitcoin-gui` will spawn a `bitcoin-node` process to run P2P and RPC code, communicating with it across a socket pair, and `bitcoin-node` will spawn `bitcoin-wallet` to run wallet code, also communicating over a socket pair. This will let node, wallet, and GUI code run in separate address spaces for better isolation, and allow future improvements like being able to start and stop components independently on different machines and environments.
+`bitcoin-node` is a drop-in replacement for `bitcoind`, and `bitcoin-gui` is a drop-in replacement for `bitcoin-qt`, and there are no differences in use or external behavior between the new and old executables. But internally `bitcoin-gui` will spawn a `bitcoin-node` process to run P2P and RPC code, communicating with it across a socket pair, and `bitcoin-node` will spawn `bitcoin-wallet` to run wallet code, also communicating over a socket pair. This lets node, wallet, and GUI code run in separate address spaces for better isolation, and allow future improvements like being able to start and stop components independently on different machines and environments.
 
 ## Next steps
 
-Specific next steps after [#10102](https://github.com/bitcoin/bitcoin/pull/10102) will be:
-
 - [ ] Adding `-ipcbind` and `-ipcconnect` options to `bitcoin-node`, `bitcoin-wallet`, and `bitcoin-gui` executables so they can listen and connect to TCP ports and unix socket paths. This will allow separate processes to be started and stopped any time and connect to each other.
 - [ ] Adding `-server` and `-rpcbind` options to the `bitcoin-wallet` executable so wallet processes can handle RPC requests directly without going through the node.
 - [ ] Supporting windows, not just unix systems. The existing socket code is already cross-platform, so the only windows-specific code that needs to be written is code spawning a process and passing a socket descriptor. This can be implemented with `CreateProcess` and `WSADuplicateSocket`. Example: https://memset.wordpress.com/2010/10/13/win32-api-passing-socket-with-ipc-method/.
@@ -34,6 +32,12 @@ The configure script will pick up settings and library locations from the depend
 
 Alternately, you can install [Cap'n Proto](https://capnproto.org/) and [libmultiprocess](https://github.com/chaincodelabs/libmultiprocess) packages on your system, and just run `./configure --enable-multiprocess` without using the depends system. The configure script will be able to locate the installed packages via [pkg-config](https://www.freedesktop.org/wiki/Software/pkg-config/). See [Installation](https://github.com/chaincodelabs/libmultiprocess#installation) section of the libmultiprocess readme for install steps. See [build-unix.md](build-unix.md) and [build-osx.md](build-osx.md) for information about installing dependencies in general.
 
+## Known issues
+
+- Unexpected socket disconnects aren't handled cleanly many places. Interface calls that used to never throw can now throw exceptions if a socket is disconnected (typically because a process on the other side of the connection has crashed or been killed), leading to errors.
+
+- Internally spawned bitcoin-node and bitcoin-wallet processes don't currently install signal handlers and so won't shut down cleanly if terminated with [CTRL-C](https://github.com/bitcoin/bitcoin/pull/10102#issuecomment-595353238). Shutting down with `bitcoin-cli stop` should still shut down cleanly, and is a suggested alternative.
+
 ## IPC implementation details
 
 Cross process Node, Wallet, and Chain interfaces are defined in

src/Makefile.am

@@ -302,7 +302,10 @@ obj/build.h: FORCE
 	  "$(abs_top_srcdir)"
 libbitcoin_util_a-clientversion.$(OBJEXT): obj/build.h
 
+# Explicitly list dependencies on generated headers as described
+# https://www.gnu.org/software/automake/manual/html_node/Built-Sources-Example.html#Recording-Dependencies-manually
 ipc/capnp/libbitcoin_ipc_a-ipc.$(OBJEXT): $(libbitcoin_ipc_mpgen_input:=.h)
+ipc/capnp/libbitcoin_ipc_a-chain.$(OBJEXT): $(libbitcoin_ipc_mpgen_input:=.h)
 
 # server: shared between bitcoind and bitcoin-qt
 # Contains code accessing mempool and chain state that is meant to be separated
@@ -649,7 +652,7 @@ bitcoin_node_SOURCES = $(bitcoin_daemon_sources) init/bitcoin-node.cpp
 bitcoin_node_CPPFLAGS = $(bitcoin_bin_cppflags)
 bitcoin_node_CXXFLAGS = $(bitcoin_bin_cxxflags)
 bitcoin_node_LDFLAGS = $(bitcoin_bin_ldflags)
-bitcoin_node_LDADD = $(LIBBITCOIN_SERVER) $(bitcoin_bin_ldadd) $(LIBBITCOIN_IPC) $(LIBMULTIPROCESS_LIBS)
+bitcoin_node_LDADD = $(LIBBITCOIN_SERVER) $(bitcoin_bin_ldadd) $(LIBBITCOIN_IPC) $(LIBBITCOIN_WALLET) $(LIBMULTIPROCESS_LIBS)
 
 # bitcoin-cli binary #
 bitcoin_cli_SOURCES = bitcoin-cli.cpp
@@ -693,10 +696,15 @@ bitcoin_tx_LDADD += $(BOOST_LIBS)
 
 # bitcoin-wallet binary #
 bitcoin_wallet_SOURCES = bitcoin-wallet.cpp
+if BUILD_MULTIPROCESS
+bitcoin_wallet_SOURCES += init/bitcoin-wallet-ipc.cpp
+else
+bitcoin_wallet_SOURCES += init/bitcoin-wallet.cpp
+endif
 bitcoin_wallet_CPPFLAGS = $(bitcoin_bin_cppflags)
 bitcoin_wallet_CXXFLAGS = $(bitcoin_bin_cxxflags)
 bitcoin_wallet_LDFLAGS = $(bitcoin_bin_ldflags)
-bitcoin_wallet_LDADD = $(LIBBITCOIN_WALLET_TOOL) $(bitcoin_bin_ldadd)
+bitcoin_wallet_LDADD = $(LIBBITCOIN_WALLET_TOOL) $(bitcoin_bin_ldadd) $(LIBBITCOIN_IPC) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_CRYPTO) $(LIBBITCOIN_UTIL) $(LIBMULTIPROCESS_LIBS)
 
 if TARGET_WINDOWS
 bitcoin_wallet_SOURCES += bitcoin-wallet-res.rc
@@ -814,17 +822,38 @@ if HARDEN
 endif
 
 libbitcoin_ipc_mpgen_input = \
+  ipc/capnp/chain.capnp \
+  ipc/capnp/common.capnp \
   ipc/capnp/echo.capnp \
-  ipc/capnp/init.capnp
+  ipc/capnp/handler.capnp \
+  ipc/capnp/init.capnp \
+  ipc/capnp/node.capnp \
+  ipc/capnp/wallet.capnp
 EXTRA_DIST += $(libbitcoin_ipc_mpgen_input)
 %.capnp:
 
 if BUILD_MULTIPROCESS
 LIBBITCOIN_IPC=libbitcoin_ipc.a
 libbitcoin_ipc_a_SOURCES = \
+  ipc/capnp/chain-types.h \
+  ipc/capnp/chain.cpp \
+  ipc/capnp/common-types.h \
+  ipc/capnp/common.cpp \
+  ipc/capnp/common.h \
+  ipc/capnp/context.h \
+  ipc/capnp/handler.cpp \
   ipc/capnp/init-types.h \
+  ipc/capnp/init.cpp \
+  ipc/capnp/node-types.h \
+  ipc/capnp/node.cpp \
+  ipc/capnp/node.h \
   ipc/capnp/protocol.cpp \
   ipc/capnp/protocol.h \
+  ipc/capnp/wallet-types.h \
+  ipc/capnp/wallet.cpp \
+  ipc/capnp/wallet.h \
+  ipc/context.cpp \
+  ipc/context.h \
   ipc/exception.h \
   ipc/interfaces.cpp \
   ipc/process.cpp \

src/Makefile.qt.include

@@ -332,15 +332,15 @@ bitcoin_qt_libtoolflags = $(AM_LIBTOOLFLAGS) --tag CXX
 
 qt_bitcoin_qt_CPPFLAGS = $(bitcoin_qt_cppflags)
 qt_bitcoin_qt_CXXFLAGS = $(bitcoin_qt_cxxflags)
-qt_bitcoin_qt_SOURCES = $(bitcoin_qt_sources)
+qt_bitcoin_qt_SOURCES = $(bitcoin_qt_sources) init/bitcoin-qt.cpp
 qt_bitcoin_qt_LDADD = $(bitcoin_qt_ldadd)
 qt_bitcoin_qt_LDFLAGS = $(bitcoin_qt_ldflags)
 qt_bitcoin_qt_LIBTOOLFLAGS = $(bitcoin_qt_libtoolflags)
 
 bitcoin_gui_CPPFLAGS = $(bitcoin_qt_cppflags)
 bitcoin_gui_CXXFLAGS = $(bitcoin_qt_cxxflags)
-bitcoin_gui_SOURCES = $(bitcoin_qt_sources)
-bitcoin_gui_LDADD = $(bitcoin_qt_ldadd)
+bitcoin_gui_SOURCES = $(bitcoin_qt_sources) init/bitcoin-gui.cpp
+bitcoin_gui_LDADD = $(bitcoin_qt_ldadd) $(LIBBITCOIN_IPC) $(LIBBITCOIN_UTIL) $(LIBMULTIPROCESS_LIBS)
 bitcoin_gui_LDFLAGS = $(bitcoin_qt_ldflags)
 bitcoin_gui_LIBTOOLFLAGS = $(bitcoin_qt_libtoolflags)
 

src/Makefile.qttest.include

@@ -36,7 +36,8 @@ qt_test_test_bitcoin_qt_SOURCES = \
   qt/test/test_main.cpp \
   qt/test/uritests.cpp \
   qt/test/util.cpp \
-  $(TEST_QT_H)
+  $(TEST_QT_H) \
+  init/bitcoin-qt.cpp
 if ENABLE_WALLET
 qt_test_test_bitcoin_qt_SOURCES += \
   qt/test/addressbooktests.cpp \

src/bitcoin-wallet.cpp

@@ -8,6 +8,7 @@
 
 #include <chainparams.h>
 #include <chainparamsbase.h>
+#include <interfaces/init.h>
 #include <logging.h>
 #include <util/system.h>
 #include <util/translation.h>
@@ -17,7 +18,7 @@
 #include <functional>
 
 const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;
-UrlDecodeFn* const URL_DECODE = nullptr;
+UrlDecodeFn* const URL_DECODE = urlDecode;
 
 static void SetupWalletToolArgs(ArgsManager& argsman)
 {
@@ -83,6 +84,13 @@ int main(int argc, char* argv[])
     util::WinCmdLineArgs winArgs;
     std::tie(argc, argv) = winArgs.get();
 #endif
+
+    int exit_status;
+    std::unique_ptr<interfaces::Init> init = interfaces::MakeWalletInit(argc, argv, exit_status);
+    if (!init) {
+        return exit_status;
+    }
+
     SetupEnvironment();
     RandomInit();
     try {

src/bitcoind.cpp

@@ -111,8 +111,8 @@ static bool AppInit(NodeContext& node, int argc, char* argv[])
     util::ThreadSetInternalName("init");
 
     // If Qt is used, parameters/bitcoin.conf are parsed in qt/bitcoin.cpp's main()
-    SetupServerArgs(node);
     ArgsManager& args = *Assert(node.args);
+    SetupServerArgs(args);
     std::string error;
     if (!args.ParseParameters(argc, argv, error)) {
         return InitError(Untranslated(strprintf("Error parsing command line arguments: %s\n", error)));