Fix error handling and filter overwriting in event.c

diff --git a/src/lib/event.c b/src/lib/event.c
index f12fcefcf6646a470616205fbff12405efff0f7f..04e9db1b2c9ed8c8fd4545e42dea1e5dcbddfdd3 100644 (file)
--- a/src/lib/event.c
+++ b/src/lib/event.c
@@ -58,6 +58,8 @@ typedef struct fr_event_fd_t {
        fr_event_fd_handler_t   write;                  //!< Callback for when we can write data.
        fr_event_fd_handler_t   error;                  //!< Callback for when an error occurs on the FD.
 
+       bool                    registered;             //!< Whether this fr_event_fd_t's FD has been registered with
+                                                       //!< kevent.
        void                    *ctx;                   //!< Context pointer to pass to each file descriptor callback.
 } fr_event_fd_t;
 
@@ -211,7 +213,11 @@ int fr_event_fd_delete(fr_event_list_t *el, int fd)
                fr_strerror_printf("No events registered for fd %i", fd);
                return -1;
        }
-       talloc_free(ef);
+       /*
+        *      Destructor may prevent ef from being
+        *      freed if kevent de-registration fails.
+        */
+       if (talloc_free(ef) < 0) return -1;
 
        return 0;
 }
@@ -228,15 +234,20 @@ static int _fr_event_fd_free(fr_event_fd_t *ef)
 
        fr_event_list_t *el = talloc_parent(ef);
 
-       rbtree_deletebydata(el->fds, ef);
-
        if (ef->read) filter |= EVFILT_READ;
        if (ef->write) filter |= EVFILT_WRITE;
 
-       EV_SET(&evset, ef->fd, filter, EV_DELETE, 0, 0, NULL);
-       (void) kevent(el->kq, &evset, 1, NULL, 0, NULL);
+       if (ef->registered) {
+               EV_SET(&evset, ef->fd, filter, EV_DELETE, 0, 0, 0);
+               if (kevent(el->kq, &evset, 1, NULL, 0, NULL) < 0) {
+                       fr_strerror_printf("Failed removing filters for FD %i: %s", ef->fd, fr_syserror(errno));
+                       return -1;
+               }
+       }
+       rbtree_deletebydata(el->fds, ef);
+       ef->registered = false;
 
-       el->num_fds++;
+       el->num_fds--;
 
        return 0;
 }
@@ -257,9 +268,10 @@ fr_event_fd_t *fr_event_fd_insert(fr_event_list_t *el, int fd,
                                  fr_event_fd_handler_t error,
                                  void *ctx)
 {
-       int             filter = 0;
-       struct kevent   evset;
-       fr_event_fd_t   *ef, find;
+       int                     filter = 0;
+       struct kevent           evset[2];
+       struct kevent           *ev_p = evset;
+       fr_event_fd_t           *ef, find;
 
        if (!el) {
                fr_strerror_printf("Invalid argument: NULL event list");
@@ -300,10 +312,24 @@ fr_event_fd_t *fr_event_fd_insert(fr_event_list_t *el, int fd,
                }
                talloc_set_destructor(ef, _fr_event_fd_free);
                el->num_fds++;
+               ef->fd = fd;
                rbtree_insert(el->fds, ef);
+       /*
+        *      Existing filters will be overwritten if there's
+        *      a new filter which takes their place.  If there
+        *      is no new filter however, we need to delete the
+        *      existing one.
+        */
+       } else {
+               if (ef->read && !read) filter |= EVFILT_READ;
+               if (ef->write && !write) filter |= EVFILT_WRITE;
+
+               if (filter) {
+                       EV_SET(ev_p++, ef->fd, filter, EV_DELETE, 0, 0, 0);
+                       filter = 0;
+               }
        }
 
-       ef->fd = fd;
        ef->ctx = ctx;
 
        if (read) {
@@ -317,12 +343,13 @@ fr_event_fd_t *fr_event_fd_insert(fr_event_list_t *el, int fd,
        }
        ef->error = error;
 
-       EV_SET(&evset, fd, filter, EV_ADD | EV_ENABLE, 0, 0, ef);
-       if (kevent(el->kq, &evset, 1, NULL, 0, NULL) < 0) {
+       EV_SET(ev_p++, fd, filter, EV_ADD | EV_ENABLE, 0, 0, ef);
+       if (kevent(el->kq, evset, ev_p - evset, NULL, 0, NULL) < 0) {
                fr_strerror_printf("Failed inserting event for FD %i: %s", fd, fr_syserror(errno));
                talloc_free(ef);
                return NULL;
        }
+       ef->registered = true;
 
        return ef;
 }