refactor: Add NodeContext::shutdown member

Add NodeContext::shutdown variable and start using it to replace the
kernel::Context::interrupt variable. The latter can't easily be removed right
away but will be removed later in this PR.

Moving the interrupt object from the kernel context to the node context
increases flexibility of the kernel API so it is possible to use multiple
interrupt objects, or avoid creating one if one is not needed. It will also
allow getting rid of the kernel::g_context global later in this PR, replacing
it with a private SignalInterrupt instance in init.cpp

There is no change in behavior in this commit outside of unit tests. In unit
tests there should be no visible change either, but internally now each test
has its own interrupt variable so the variable will be automatically reset
between tests.

src/bitcoin-chainstate.cpp

@@ -125,7 +125,8 @@ int main(int argc, char* argv[])
         .blocks_dir = abs_datadir / "blocks",
         .notifications = chainman_opts.notifications,
     };
-    ChainstateManager chainman{kernel_context.interrupt, chainman_opts, blockman_opts};
+    util::SignalInterrupt interrupt;
+    ChainstateManager chainman{interrupt, chainman_opts, blockman_opts};
 
     node::CacheSizes cache_sizes;
     cache_sizes.block_tree_db = 2 << 20;

src/bitcoind.cpp

@@ -185,6 +185,7 @@ static bool AppInit(NodeContext& node)
         }
 
         node.kernel = std::make_unique<kernel::Context>();
+        node.shutdown = &node.kernel->interrupt; // TEMPORARY: will go away when kernel->interrupt member is removed
         if (!AppInitSanityChecks(*node.kernel))
         {
             // InitError will have been called with detailed error, which ends up on console

src/init.cpp

@@ -1485,7 +1485,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     for (bool fLoaded = false; !fLoaded && !ShutdownRequested();) {
         node.mempool = std::make_unique<CTxMemPool>(mempool_opts);
 
-        node.chainman = std::make_unique<ChainstateManager>(node.kernel->interrupt, chainman_opts, blockman_opts);
+        node.chainman = std::make_unique<ChainstateManager>(*Assert(node.shutdown), chainman_opts, blockman_opts);
         ChainstateManager& chainman = *node.chainman;
 
         // This is defined and set here instead of inline in validation.h to avoid a hard

src/node/context.h

@@ -50,6 +50,8 @@ struct NodeContext {
     std::unique_ptr<kernel::Context> kernel;
     //! Init interface for initializing current process and connecting to other processes.
     interfaces::Init* init{nullptr};
+    //! Interrupt object used to track whether node shutdown was requested.
+    util::SignalInterrupt* shutdown{nullptr};
     std::unique_ptr<AddrMan> addrman;
     std::unique_ptr<CConnman> connman;
     std::unique_ptr<CTxMemPool> mempool;

src/node/interfaces.cpp

@@ -99,6 +99,7 @@ public:
         if (!AppInitParameterInteraction(args())) return false;
 
         m_context->kernel = std::make_unique<kernel::Context>();
+        m_context->shutdown = &m_context->kernel->interrupt; // TEMPORARY: will go away when kernel->interrupt member is removed
         if (!AppInitSanityChecks(*m_context->kernel)) return false;
 
         if (!AppInitLockDataDirectory()) return false;

src/test/blockmanager_tests.cpp

@@ -33,7 +33,7 @@ BOOST_AUTO_TEST_CASE(blockmanager_find_block_pos)
         .blocks_dir = m_args.GetBlocksDirPath(),
         .notifications = notifications,
     };
-    BlockManager blockman{m_node.kernel->interrupt, blockman_opts};
+    BlockManager blockman{*Assert(m_node.shutdown), blockman_opts};
     // simulate adding a genesis block normally
     BOOST_CHECK_EQUAL(blockman.SaveBlockToDisk(params->GenesisBlock(), 0, nullptr).nPos, BLOCK_SERIALIZATION_HEADER_SIZE);
     // simulate what happens during reindex

src/test/util/setup_common.cpp

@@ -102,6 +102,7 @@ BasicTestingSetup::BasicTestingSetup(const ChainType chainType, const std::vecto
     : m_path_root{fs::temp_directory_path() / "test_common_" PACKAGE_NAME / g_insecure_rand_ctx_temp_path.rand256().ToString()},
       m_args{}
 {
+    m_node.shutdown = &m_interrupt;
     m_node.args = &gArgs;
     std::vector<const char*> arguments = Cat(
         {
@@ -194,7 +195,7 @@ ChainTestingSetup::ChainTestingSetup(const ChainType chainType, const std::vecto
         .blocks_dir = m_args.GetBlocksDirPath(),
         .notifications = chainman_opts.notifications,
     };
-    m_node.chainman = std::make_unique<ChainstateManager>(m_node.kernel->interrupt, chainman_opts, blockman_opts);
+    m_node.chainman = std::make_unique<ChainstateManager>(*Assert(m_node.shutdown), chainman_opts, blockman_opts);
     m_node.chainman->m_blockman.m_block_tree_db = std::make_unique<BlockTreeDB>(DBParams{
         .path = m_args.GetDataDirNet() / "blocks" / "index",
         .cache_bytes = static_cast<size_t>(m_cache_sizes.block_tree_db),

src/test/util/setup_common.h

@@ -47,6 +47,7 @@ static constexpr CAmount CENT{1000000};
  * This just configures logging, data dir and chain parameters.
  */
 struct BasicTestingSetup {
+    util::SignalInterrupt m_interrupt;
     node::NodeContext m_node; // keep as first member to be destructed last
 
     explicit BasicTestingSetup(const ChainType chainType = ChainType::MAIN, const std::vector<const char*>& extra_args = {});

src/test/validation_chainstatemanager_tests.cpp

@@ -394,7 +394,7 @@ struct SnapshotTestSetup : TestChain100Setup {
             // For robustness, ensure the old manager is destroyed before creating a
             // new one.
             m_node.chainman.reset();
-            m_node.chainman = std::make_unique<ChainstateManager>(m_node.kernel->interrupt, chainman_opts, blockman_opts);
+            m_node.chainman = std::make_unique<ChainstateManager>(*Assert(m_node.shutdown), chainman_opts, blockman_opts);
         }
         return *Assert(m_node.chainman);
     }