util: Add -shutdownnotify option. (#1345)

Co-authored-by: klementtan <[email protected]>
Co-authored-by: Prasanna Loganathar <[email protected]>

src/init.cpp

@@ -163,8 +163,24 @@ static std::unique_ptr<ECCVerifyHandle> globalVerifyHandle;
 static boost::thread_group threadGroup;
 static CScheduler scheduler;
 
+#if HAVE_SYSTEM
+static void ShutdownNotify()
+{
+    std::vector<std::thread> threads;
+    for (const auto& cmd : gArgs.GetArgs("-shutdownnotify")) {
+        threads.emplace_back(runCommand, cmd);
+    }
+    for (auto& t : threads) {
+        t.join();
+    }
+}
+#endif
+
 void Interrupt()
 {
+#if HAVE_SYSTEM
+    ShutdownNotify();
+#endif
     InterruptHTTPServer();
     InterruptHTTPRPC();
     InterruptRPC();
@@ -376,7 +392,7 @@ void SetupServerArgs()
 
     // Hidden Options
     std::vector<std::string> hidden_args = {
-        "-dbcrashratio", "-forcecompactdb", 
+        "-dbcrashratio", "-forcecompactdb",
         "-interrupt-block=<hash|height>", "-stop-block=<hash|height>",
         "-mocknet", "-mocknet-blocktime=<secs>", "-mocknet-key=<pubkey>"
         // GUI args. These will be overwritten by SetupUIArgs for the GUI
@@ -416,6 +432,9 @@ void SetupServerArgs()
             "(default: 0 = disable pruning blocks, 1 = allow manual pruning via RPC, >=%u = automatically prune block files to stay under the specified target size in MiB)", MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-reindex", "Rebuild chain state and block index from the blk*.dat files on disk", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-reindex-chainstate", "Rebuild chain state from the currently indexed blocks. When in pruning mode or if blocks on disk might be corrupted, use full -reindex instead.", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+#if HAVE_SYSTEM
+    gArgs.AddArg("-shutdownnotify=<cmd>", "Execute command immediately before beginning shutdown. The need for shutdown may be urgent, so be careful not to delay it long (if the command doesn't require interaction with the server, consider having it fork into the background).", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+#endif
 #ifndef WIN32
     gArgs.AddArg("-sysperms", "Create new files with system default permissions, instead of umask 077 (only effective with disabled wallet functionality)", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #else
@@ -1241,7 +1260,7 @@ bool AppInitParameterInteraction()
     nMaxTipAge = gArgs.GetArg("-maxtipage", DEFAULT_MAX_TIP_AGE);
     fIsFakeNet = Params().NetworkIDString() == "regtest" && gArgs.GetArg("-dummypos", false);
     CTxOut::SERIALIZE_FORCED_TO_OLD_IN_TESTS = Params().NetworkIDString() == "regtest" && gArgs.GetArg("-txnotokens", false);
-    
+
     return true;
 }