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.

9 files changed, 12 insertions, 5 deletions

diff --git a/src/bitcoin-chainstate.cpp b/src/bitcoin-chainstate.cpp
index f241bdae4d..ee8b0a44c5 100644
--- a/src/bitcoin-chainstate.cpp
+++ b/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;
diff --git a/src/bitcoind.cpp b/src/bitcoind.cpp
index e2224befef..ccdc628a0f 100644
--- a/src/bitcoind.cpp
+++ b/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
diff --git a/src/init.cpp b/src/init.cpp
index 8bff75ec91..dfc05ebb67 100644
--- a/src/init.cpp
+++ b/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
diff --git a/src/node/context.h b/src/node/context.h
index dae900ff7f..4f3b640b2d 100644
--- a/src/node/context.h
+++ b/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;
diff --git a/src/node/interfaces.cpp b/src/node/interfaces.cpp
index b5691f0e57..088497399a 100644
--- a/src/node/interfaces.cpp
+++ b/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;
diff --git a/src/test/blockmanager_tests.cpp b/src/test/blockmanager_tests.cpp
index e1b31c20f4..8a777ee5ff 100644
--- a/src/test/blockmanager_tests.cpp
+++ b/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
diff --git a/src/test/util/setup_common.cpp b/src/test/util/setup_common.cpp
index bc639da4dd..4b700b18d6 100644
--- a/src/test/util/setup_common.cpp
+++ b/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),
diff --git a/src/test/util/setup_common.h b/src/test/util/setup_common.h
index c3a4df28bf..9ff4c372a5 100644
--- a/src/test/util/setup_common.h
+++ b/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 = {});
diff --git a/src/test/validation_chainstatemanager_tests.cpp b/src/test/validation_chainstatemanager_tests.cpp
index 6969822ad7..6c81cd618b 100644
--- a/src/test/validation_chainstatemanager_tests.cpp
+++ b/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);
     }