tevent: ignore POLLNVAL from poll() and disable the event

Signed-off-by: Stefan Metzmacher <metze@samba.org>

diff --git a/lib/tevent/tevent_poll.c b/lib/tevent/tevent_poll.c
index 763a139c7c5fbc350431c3488a9f77aa3ec04b18..867d951ee1b1bcee2e35e503501d31d37ad2713e 100644 (file)
--- a/lib/tevent/tevent_poll.c
+++ b/lib/tevent/tevent_poll.c
@@ -501,6 +501,7 @@ static int poll_event_loop_poll(struct tevent_context *ev,
        int timeout = -1;
        int poll_errno;
        struct tevent_fd *fde = NULL;
+       unsigned i;
 
        if (ev->signal_events && tevent_common_check_signal(ev)) {
                return 0;
@@ -555,6 +556,26 @@ static int poll_event_loop_poll(struct tevent_context *ev,
 
                pfd = &poll_ev->fds[idx];
 
+               if (pfd->revents & POLLNVAL) {
+                       /*
+                        * the socket is dead! this should never
+                        * happen as the socket should have first been
+                        * made readable and that should have removed
+                        * the event, so this must be a bug.
+                        *
+                        * We ignore it here to match the epoll
+                        * behavior.
+                        */
+                       tevent_debug(ev, TEVENT_DEBUG_ERROR,
+                                    "POLLNVAL on fde[%p] fd[%d] - disabling\n",
+                                    fde, pfd->fd);
+                       poll_ev->fdes[idx] = NULL;
+                       poll_ev->deleted = true;
+                       DLIST_REMOVE(ev->fd_events, fde);
+                       fde->event_ctx = NULL;
+                       continue;
+               }
+
                if (pfd->revents & (POLLHUP|POLLERR)) {
                        /* If we only wait for TEVENT_FD_WRITE, we
                           should not tell the event handler about it,
@@ -575,7 +596,29 @@ static int poll_event_loop_poll(struct tevent_context *ev,
                }
                if (flags != 0) {
                        fde->handler(ev, fde, flags, fde->private_data);
-                       break;
+                       return 0;
+               }
+       }
+
+       for (i = 0; i < poll_ev->num_fds; i++) {
+               if (poll_ev->fds[i].revents & POLLNVAL) {
+                       /*
+                        * the socket is dead! this should never
+                        * happen as the socket should have first been
+                        * made readable and that should have removed
+                        * the event, so this must be a bug or
+                        * a race in the poll_mt usage.
+                        */
+                       fde = poll_ev->fdes[i];
+                       tevent_debug(ev, TEVENT_DEBUG_WARNING,
+                                    "POLLNVAL on dangling fd[%d] fde[%p] - disabling\n",
+                                    poll_ev->fds[i].fd, fde);
+                       poll_ev->fdes[i] = NULL;
+                       poll_ev->deleted = true;
+                       if (fde != NULL) {
+                               DLIST_REMOVE(ev->fd_events, fde);
+                               fde->event_ctx = NULL;
+                       }
                }
        }