linux: close streams without an extra read (#3250)

src/unix/linux.c

@@ -1516,25 +1516,6 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
        */
       pe->events &= w->pevents | POLLERR | POLLHUP;
 
-      /* Work around an epoll quirk where it sometimes reports just the
-       * EPOLLERR or EPOLLHUP event.  In order to force the event loop to
-       * move forward, we merge in the read/write events that the watcher
-       * is interested in; uv__read() and uv__write() will then deal with
-       * the error or hangup in the usual fashion.
-       *
-       * Note to self: happens when epoll reports EPOLLIN|EPOLLHUP, the user
-       * reads the available data, calls uv_read_stop(), then sometime later
-       * calls uv_read_start() again.  By then, libuv has forgotten about the
-       * hangup and the kernel won't report EPOLLIN again because there's
-       * nothing left to read.  If anything, libuv is to blame here.  The
-       * current hack is just a quick bandaid; to properly fix it, libuv
-       * needs to remember the error/hangup event.  We should get that for
-       * free when we switch over to edge-triggered I/O.
-       */
-      if (pe->events == POLLERR || pe->events == POLLHUP)
-        pe->events |=
-          w->pevents & (POLLIN | POLLOUT | UV__POLLRDHUP | UV__POLLPRI);
-
       if (pe->events != 0) {
         /* Run signal watchers last.  This also affects child process watchers
          * because those are implemented in terms of signal watchers.

src/unix/poll.c

@@ -60,6 +60,12 @@ void uv__poll_io(uv_loop_t* loop, uv__io_t* w, unsigned int events) {
   if (events & UV__POLLRDHUP)
     pevents |= UV_DISCONNECT;
 
+  /* On error or hangup, mix in events the user is interested in so the
+   * appropriate read/write callbacks are invoked. */
+  if (events & (POLLERR | POLLHUP))
+    pevents |=
+      w->pevents & (UV_READABLE | UV_PRIORITIZED | UV_WRITABLE | UV_DISCONNECT);
+
   handle->poll_cb(handle, 0, pevents);
 }
 

src/unix/stream.c

@@ -1218,16 +1218,15 @@ void uv__stream_io(uv_loop_t* loop, uv__io_t* w, unsigned int events) {
    * operating systems, devices like PTYs sometimes produce partial reads even
    * when more data is available.
    */
-  if ((events & POLLHUP) &&
+  if ((events & (POLLHUP | UV__POLLRDHUP)) &&
       !(events & POLLIN) &&
       (stream->flags & UV_HANDLE_READING) &&
       !(stream->flags & UV_HANDLE_READ_EOF)) {
     uv_buf_t buf = { NULL, 0 };
     uv__stream_eof(stream, &buf);
-  }
-
     if (uv__stream_fd(stream) == -1)
       return;  /* read_cb closed stream. */
+  }
 
   if (events & (POLLOUT | POLLERR | POLLHUP)) {
     uv__write(stream);

src/unix/udp.c

@@ -178,7 +178,11 @@ void uv__udp_io(uv_loop_t* loop, uv__io_t* w, unsigned int revents) {
   handle = container_of(w, uv_udp_t, io_watcher);
   assert(handle->type == UV_UDP);
 
-  if (revents & POLLIN)
+  /* Trigger a recv and send to find out what POLLERR occurred. */
+  if (revents & POLLERR)
+    revents |= POLLIN | POLLOUT;
+
+  if (revents & (POLLIN | POLLERR))
     uv__udp_recvmsg(handle, 0);
 
   /* Just Linux support for now. */