Merge tag 'v0.21.23'

release v0.21.23

src/event/PollGroupWinSelect.cxx

@@ -23,8 +23,8 @@
 
 #include "PollGroupWinSelect.hxx"
 
-constexpr int EVENT_READ = 0;
-constexpr int EVENT_WRITE = 1;
+static constexpr int EVENT_READ = 0;
+static constexpr int EVENT_WRITE = 1;
 
 static constexpr
 bool HasEvent(unsigned events, int event_id) noexcept

src/event/SocketMonitor.cxx

@@ -23,6 +23,10 @@
 #include <cassert>
 #include <utility>
 
+#ifdef USE_EPOLL
+#include <cerrno>
+#endif
+
 void
 SocketMonitor::Dispatch(unsigned flags) noexcept
 {
@@ -81,6 +85,21 @@ SocketMonitor::Schedule(unsigned flags) noexcept
 
 	if (success)
 		scheduled_flags = flags;
+#ifdef USE_EPOLL
+	else if (errno == EBADF || errno == ENOENT)
+		/* the socket was probably closed by somebody else
+		   (EBADF) or a new file descriptor with the same
+		   number was created but not registered already
+		   (ENOENT) - we can assume that there are no
+		   scheduled events */
+		/* note that when this happens, we're actually lucky
+		   that it has failed - imagine another thread may
+		   meanwhile have created something on the same file
+		   descriptor number, and has registered it; the
+		   epoll_ctl() call above would then have succeeded,
+		   but broke the other thread's epoll registration */
+		scheduled_flags = 0;
+#endif
 
 	return success;
 }

src/event/SocketMonitor.hxx

@@ -108,7 +108,7 @@ public:
 	}
 
 	bool ScheduleRead() noexcept {
-		return Schedule(GetScheduledFlags() | READ | HANGUP | ERROR);
+		return Schedule(GetScheduledFlags() | READ);
 	}
 
 	bool ScheduleWrite() noexcept {
@@ -116,7 +116,7 @@ public:
 	}
 
 	void CancelRead() noexcept {
-		Schedule(GetScheduledFlags() & ~(READ|HANGUP|ERROR));
+		Schedule(GetScheduledFlags() & ~READ);
 	}
 
 	void CancelWrite() noexcept {