From 8c6d007c80dc3fec5ce6c0196381444a5ed7e424 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Barbosa?= <joao.paulo.barbosa@gmail.com>
Date: Tue, 30 Jun 2020 00:05:47 +0100
Subject: [PATCH 1/3] http: Track active requests and wait for last to finish

---
 src/httpserver.cpp | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index 6f84d5c83bd..f49f2b3f37b 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -21,12 +21,14 @@
 #include <util/threadnames.h>
 #include <util/translation.h>
 
+#include <condition_variable>
 #include <cstdio>
 #include <cstdlib>
 #include <deque>
 #include <memory>
 #include <optional>
 #include <string>
+#include <unordered_set>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -34,6 +36,7 @@
 #include <event2/buffer.h>
 #include <event2/bufferevent.h>
 #include <event2/http.h>
+#include <event2/http_struct.h>
 #include <event2/keyvalq_struct.h>
 #include <event2/thread.h>
 #include <event2/util.h>
@@ -146,6 +149,10 @@ static GlobalMutex g_httppathhandlers_mutex;
 static std::vector<HTTPPathHandler> pathHandlers GUARDED_BY(g_httppathhandlers_mutex);
 //! Bound listening sockets
 static std::vector<evhttp_bound_socket *> boundSockets;
+//! Track active requests
+static GlobalMutex g_requests_mutex;
+static std::condition_variable g_requests_cv;
+static std::unordered_set<evhttp_request*> g_requests GUARDED_BY(g_requests_mutex);
 
 /** Check if a network address is allowed to access the HTTP server */
 static bool ClientAllowed(const CNetAddr& netaddr)
@@ -207,6 +214,17 @@ std::string RequestMethodString(HTTPRequest::RequestMethod m)
 /** HTTP request callback */
 static void http_request_cb(struct evhttp_request* req, void* arg)
 {
+    // Track requests and notify when a request is completed.
+    {
+        WITH_LOCK(g_requests_mutex, g_requests.insert(req));
+        g_requests_cv.notify_all();
+        evhttp_request_set_on_complete_cb(req, [](struct evhttp_request* req, void*) {
+            auto n{WITH_LOCK(g_requests_mutex, return g_requests.erase(req))};
+            assert(n == 1);
+            g_requests_cv.notify_all();
+        }, nullptr);
+    }
+
     // Disable reading to work around a libevent bug, fixed in 2.2.0.
     if (event_get_version_number() >= 0x02010600 && event_get_version_number() < 0x02020001) {
         evhttp_connection* conn = evhttp_request_get_connection(req);
@@ -459,6 +477,15 @@ void StopHTTPServer()
         evhttp_del_accept_socket(eventHTTP, socket);
     }
     boundSockets.clear();
+    {
+        WAIT_LOCK(g_requests_mutex, lock);
+        if (!g_requests.empty()) {
+            LogPrint(BCLog::HTTP, "Waiting for %d requests to stop HTTP server\n", g_requests.size());
+        }
+        g_requests_cv.wait(lock, []() EXCLUSIVE_LOCKS_REQUIRED(g_requests_mutex) {
+            return g_requests.empty();
+        });
+    }
     if (eventBase) {
         LogPrint(BCLog::HTTP, "Waiting for HTTP event thread to exit\n");
         if (g_thread_http.joinable()) g_thread_http.join();

From 660bdbf785a32024f0694915fa043968a0afb573 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Barbosa?= <joao.paulo.barbosa@gmail.com>
Date: Sat, 3 Aug 2019 02:52:53 +0100
Subject: [PATCH 2/3] http: Release server before waiting for event base loop
 exit

---
 src/httpserver.cpp | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index f49f2b3f37b..5c1bbc87fcf 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -486,15 +486,18 @@ void StopHTTPServer()
             return g_requests.empty();
         });
     }
+    if (eventHTTP) {
+        // Schedule a callback to call evhttp_free in the event base thread, so
+        // that evhttp_free does not need to be called again after the handling
+        // of unfinished request connections that follows.
+        event_base_once(eventBase, -1, EV_TIMEOUT, [](evutil_socket_t, short, void*) {
+            evhttp_free(eventHTTP);
+            eventHTTP = nullptr;
+        }, nullptr, nullptr);
+    }
     if (eventBase) {
         LogPrint(BCLog::HTTP, "Waiting for HTTP event thread to exit\n");
         if (g_thread_http.joinable()) g_thread_http.join();
-    }
-    if (eventHTTP) {
-        evhttp_free(eventHTTP);
-        eventHTTP = nullptr;
-    }
-    if (eventBase) {
         event_base_free(eventBase);
         eventBase = nullptr;
     }

From 60978c8080ec13ff4571c8a89e742517b2aca692 Mon Sep 17 00:00:00 2001
From: Fabian Jahr <fjahr@protonmail.com>
Date: Thu, 5 Jan 2023 12:56:19 +0100
Subject: [PATCH 3/3] test: Reduce extended timeout on abortnode test

This was made obsolete by tracking the active requests and explicitly waiting for them to finish before shutdown.
---
 test/functional/feature_abortnode.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/test/functional/feature_abortnode.py b/test/functional/feature_abortnode.py
index 32cf4a47f48..fa1bb6506ab 100755
--- a/test/functional/feature_abortnode.py
+++ b/test/functional/feature_abortnode.py
@@ -19,7 +19,6 @@ class AbortNodeTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
-        self.rpc_timeout = 240
 
     def setup_network(self):
         self.setup_nodes()
@@ -41,7 +40,7 @@ class AbortNodeTest(BitcoinTestFramework):
 
             # Check that node0 aborted
             self.log.info("Waiting for crash")
-            self.nodes[0].wait_until_stopped(timeout=200)
+            self.nodes[0].wait_until_stopped(timeout=5)
         self.log.info("Node crashed - now verifying restart fails")
         self.nodes[0].assert_start_raises_init_error()