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-rw-r--r--src/httpserver.cpp86
1 files changed, 70 insertions, 16 deletions
diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index a83f4421d7..3ad329a669 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -17,6 +17,7 @@
#include <rpc/protocol.h> // For HTTP status codes
#include <shutdown.h>
#include <sync.h>
+#include <util/check.h>
#include <util/strencodings.h>
#include <util/threadnames.h>
#include <util/translation.h>
@@ -26,9 +27,10 @@
#include <cstdlib>
#include <deque>
#include <memory>
+#include <numeric>
#include <optional>
#include <string>
-#include <unordered_set>
+#include <unordered_map>
#include <sys/types.h>
#include <sys/stat.h>
@@ -149,10 +151,68 @@ 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;
+
+/**
+ * @brief Helps keep track of open `evhttp_connection`s with active `evhttp_requests`
+ *
+ */
+class HTTPRequestTracker
+{
+private:
+ mutable Mutex m_mutex;
+ mutable std::condition_variable m_cv;
+ //! For each connection, keep a counter of how many requests are open
+ std::unordered_map<const evhttp_connection*, size_t> m_tracker GUARDED_BY(m_mutex);
+
+ void RemoveConnectionInternal(const decltype(m_tracker)::iterator it) EXCLUSIVE_LOCKS_REQUIRED(m_mutex)
+ {
+ m_tracker.erase(it);
+ if (m_tracker.empty()) m_cv.notify_all();
+ }
+public:
+ //! Increase request counter for the associated connection by 1
+ void AddRequest(evhttp_request* req) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
+ {
+ const evhttp_connection* conn{Assert(evhttp_request_get_connection(Assert(req)))};
+ WITH_LOCK(m_mutex, ++m_tracker[conn]);
+ }
+ //! Decrease request counter for the associated connection by 1, remove connection if counter is 0
+ void RemoveRequest(evhttp_request* req) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
+ {
+ const evhttp_connection* conn{Assert(evhttp_request_get_connection(Assert(req)))};
+ LOCK(m_mutex);
+ auto it{m_tracker.find(conn)};
+ if (it != m_tracker.end() && it->second > 0) {
+ if (--(it->second) == 0) RemoveConnectionInternal(it);
+ }
+ }
+ //! Remove a connection entirely
+ void RemoveConnection(const evhttp_connection* conn) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
+ {
+ LOCK(m_mutex);
+ auto it{m_tracker.find(Assert(conn))};
+ if (it != m_tracker.end()) RemoveConnectionInternal(it);
+ }
+
+ size_t CountActiveRequests() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
+ {
+ LOCK(m_mutex);
+ return std::accumulate(m_tracker.begin(), m_tracker.end(), size_t(0),
+ [](size_t acc_count, const auto& pair) { return acc_count + pair.second; });
+ }
+ size_t CountActiveConnections() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
+ {
+ return WITH_LOCK(m_mutex, return m_tracker.size());
+ }
+ //! Wait until there are no more connections with active requests in the tracker
+ void WaitUntilEmpty() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
+ {
+ WAIT_LOCK(m_mutex, lock);
+ m_cv.wait(lock, [this]() EXCLUSIVE_LOCKS_REQUIRED(m_mutex) { return m_tracker.empty(); });
+ }
+};
//! 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);
+static HTTPRequestTracker g_requests;
/** Check if a network address is allowed to access the HTTP server */
static bool ClientAllowed(const CNetAddr& netaddr)
@@ -210,14 +270,11 @@ 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.
+ // Track active requests
{
- WITH_LOCK(g_requests_mutex, g_requests.insert(req));
- g_requests_cv.notify_all();
+ g_requests.AddRequest(req);
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();
+ g_requests.RemoveRequest(req);
}, nullptr);
}
@@ -473,13 +530,10 @@ void StopHTTPServer()
}
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());
+ if (g_requests.CountActiveConnections() != 0) {
+ LogPrint(BCLog::HTTP, "Waiting for %d requests to stop HTTP server\n", g_requests.CountActiveRequests());
}
- g_requests_cv.wait(lock, []() EXCLUSIVE_LOCKS_REQUIRED(g_requests_mutex) {
- return g_requests.empty();
- });
+ g_requests.WaitUntilEmpty();
}
if (eventHTTP) {
// Schedule a callback to call evhttp_free in the event base thread, so