net: restrict access EdgeTriggerEvents members

- File descriptor creation and destruction are handled within ETE, no
  reason to expose read-write access to it.
- (Un)registerPipe should only be used within WakeupPipe, remove from
  public view.

Author: kwvg

src/net.cpp

@@ -1598,7 +1598,7 @@ void CConnman::SocketEventsKqueue(std::set<SOCKET>& recv_set,
     timeout.tv_nsec = (only_poll ? 0 : SELECT_TIMEOUT_MILLISECONDS % 1000) * 1000 * 1000;
 
     int n{-1};
-    ToggleWakeupPipe([&](){n = kevent(Assert(m_edge_trig_events)->m_fd, nullptr, 0, events, maxEvents, &timeout);});
+    ToggleWakeupPipe([&](){n = kevent(Assert(m_edge_trig_events)->GetFileDescriptor(), nullptr, 0, events, maxEvents, &timeout);});
     if (n == -1) {
         LogPrintf("kevent wait error\n");
     } else if (n > 0) {
@@ -1631,7 +1631,7 @@ void CConnman::SocketEventsEpoll(std::set<SOCKET>& recv_set,
     epoll_event events[maxEvents];
 
     int n{-1};
-    ToggleWakeupPipe([&](){n = epoll_wait(Assert(m_edge_trig_events)->m_fd, events, maxEvents, only_poll ? 0 : SELECT_TIMEOUT_MILLISECONDS);});
+    ToggleWakeupPipe([&](){n = epoll_wait(Assert(m_edge_trig_events)->GetFileDescriptor(), events, maxEvents, only_poll ? 0 : SELECT_TIMEOUT_MILLISECONDS);});
     for (int i = 0; i < n; i++) {
         auto& e = events[i];
         if((e.events & EPOLLERR) || (e.events & EPOLLHUP)) {

src/util/edge.cpp

@@ -7,8 +7,6 @@
 #include <logging.h>
 #include <util/sock.h>
 
-#include <assert.h>
-
 #ifdef USE_EPOLL
 #include <sys/epoll.h>
 #endif

src/util/edge.h

@@ -7,6 +7,7 @@
 
 #include <compat.h>
 
+#include <assert.h>
 #include <cstdint>
 #include <string>
 
@@ -23,37 +24,38 @@ class EdgeTriggeredEvents
     ~EdgeTriggeredEvents();
 
     bool IsValid() const { return m_valid; }
+    int GetFileDescriptor() const { assert(m_fd != -1); return m_fd; }
 
     /* Add socket to interest list */
     bool AddSocket(SOCKET socket) const;
     /* Remove socket from interest list */
     bool RemoveSocket(SOCKET socket) const;
 
-    /* Register wakeup pipe with EdgeTriggeredEvents instance */
-    bool RegisterPipe(int wakeup_pipe);
-    /* Unregister wakeup pipe with EdgeTriggeredEvents instance */
-    bool UnregisterPipe(int wakeup_pipe);
-
     /* Register events for socket */
     bool RegisterEvents(SOCKET socket) const;
     /* Unregister events for socket */
     bool UnregisterEvents(SOCKET socket) const;
 
+private:
+    friend class WakeupPipe;
+    /* Register wakeup pipe with EdgeTriggeredEvents instance */
+    bool RegisterPipe(int wakeup_pipe);
+    /* Unregister wakeup pipe with EdgeTriggeredEvents instance */
+    bool UnregisterPipe(int wakeup_pipe);
+
 private:
     bool RegisterEntity(int entity, std::string entity_name) const;
     bool UnregisterEntity(int entity, std::string entity_name) const;
 
-public:
-    /* File descriptor used to interact with events mode */
-    int m_fd{-1};
-
 private:
     /* Flag set if pipe has been registered with instance */
     bool m_pipe_registered{false};
     /* Instance validity flag set during construction */
     bool m_valid{false};
     /* Flag for storing selected socket events mode */
     SocketEventsMode m_mode;
+    /* File descriptor used to interact with events mode */
+    int m_fd{-1};
 };
 
 #endif /* BITCOIN_UTIL_EDGE_H */