Merge bitcoin/bitcoin#26034: [22.x] Prevent data race for `pathHandlers`

2c6c628ab95b018ac7ce6595954644bf9197ce35 Prevent data race for `pathHandlers` (Hennadii Stepanov)

Pull request description:

  Backport of https://github.com/bitcoin/bitcoin/pull/25983 to the 22.x branch.

ACKs for top commit:
  dergoegge:
    ACK 2c6c628ab95b018ac7ce6595954644bf9197ce35

Tree-SHA512: 9b172f73407fdd5a79e67ed1b2b3b7c6e7989ea1de6757c839ee7040d62ebbd87d10770c6fcb39709a07d52345dc9b7b244ef2b490c9ad8a656ff8ad4d618a01

1 files changed, 5 insertions, 1 deletions

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index 8741ad9b86..fb00fbc30b 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -138,7 +138,8 @@ static std::vector<CSubNet> rpc_allow_subnets;
 //! Work queue for handling longer requests off the event loop thread
 static std::unique_ptr<WorkQueue<HTTPClosure>> g_work_queue{nullptr};
 //! Handlers for (sub)paths
-static std::vector<HTTPPathHandler> pathHandlers;
+static Mutex g_httppathhandlers_mutex;
+static std::vector<HTTPPathHandler> pathHandlers GUARDED_BY(g_httppathhandlers_mutex);
 //! Bound listening sockets
 static std::vector<evhttp_bound_socket *> boundSockets;
 
@@ -239,6 +240,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)
     // Find registered handler for prefix
     std::string strURI = hreq->GetURI();
     std::string path;
+    LOCK(g_httppathhandlers_mutex);
     std::vector<HTTPPathHandler>::const_iterator i = pathHandlers.begin();
     std::vector<HTTPPathHandler>::const_iterator iend = pathHandlers.end();
     for (; i != iend; ++i) {
@@ -633,11 +635,13 @@ HTTPRequest::RequestMethod HTTPRequest::GetRequestMethod() const
 void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler)
 {
     LogPrint(BCLog::HTTP, "Registering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
+    LOCK(g_httppathhandlers_mutex);
     pathHandlers.push_back(HTTPPathHandler(prefix, exactMatch, handler));
 }
 
 void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch)
 {
+    LOCK(g_httppathhandlers_mutex);
     std::vector<HTTPPathHandler>::iterator i = pathHandlers.begin();
     std::vector<HTTPPathHandler>::iterator iend = pathHandlers.end();
     for (; i != iend; ++i)