[src/trunk]: src/sys/kern - initialize kn_id

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/53401a7725c9
branches:  trunk
changeset: 782871:53401a7725c9
user:      christos <christos%NetBSD.org@localhost>
date:      Sat Nov 24 15:14:32 2012 +0000

description:
- initialize kn_id
- in close, invalidate f_data and f_type early to prevent accidental re-use
- add a DIAGNOSTIC for when we use unsupported fd's and a KASSERT for f_event
  being NULL.

diffstat:

 sys/kern/kern_event.c |  19 ++++++++++++++++---
 1 files changed, 16 insertions(+), 3 deletions(-)

diffs (68 lines):

diff -r 228e59b62c95 -r 53401a7725c9 sys/kern/kern_event.c
--- a/sys/kern/kern_event.c     Sat Nov 24 15:07:44 2012 +0000
+++ b/sys/kern/kern_event.c     Sat Nov 24 15:14:32 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_event.c,v 1.78 2012/11/18 18:36:01 pooka Exp $    */
+/*     $NetBSD: kern_event.c,v 1.79 2012/11/24 15:14:32 christos Exp $ */
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.78 2012/11/18 18:36:01 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.79 2012/11/24 15:14:32 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -972,6 +972,7 @@
                        kn = newkn;
                        newkn = NULL;
                        kn->kn_obj = fp;
+                       kn->kn_id = kev->ident;
                        kn->kn_kq = kq;
                        kn->kn_fop = kfilter->filtops;
                        kn->kn_kfilter = kfilter;
@@ -1013,6 +1014,10 @@
                        error = (*kfilter->filtops->f_attach)(kn);
                        KERNEL_UNLOCK_ONE(NULL);        /* XXXSMP */
                        if (error != 0) {
+#ifdef DIAGNOSTIC
+                               printf("%s: event not supported for file type"
+                                   " %d\n", __func__, fp ? fp->f_type : -1);
+#endif
                                /* knote_detach() drops fdp->fd_lock */
                                knote_detach(kn, fdp, false);
                                goto done;
@@ -1028,6 +1033,13 @@
                        kn->kn_sdata = kev->data;
                        kn->kn_kevent.udata = kev->udata;
                }
+               /*
+                * We can get here if we are trying to attach
+                * an event to a file descriptor that does not
+                * support events, and the attach routine is
+                * broken and does not return an error.
+                */
+               KASSERT(kn->kn_fop->f_event != NULL);
                KERNEL_LOCK(1, NULL);                   /* XXXSMP */
                rv = (*kn->kn_fop->f_event)(kn, 0);
                KERNEL_UNLOCK_ONE(NULL);                /* XXXSMP */
@@ -1432,6 +1444,8 @@
        int i;
 
        kq = fp->f_data;
+       fp->f_data = NULL;
+       fp->f_type = 0;
        fdp = curlwp->l_fd;
 
        mutex_enter(&fdp->fd_lock);
@@ -1452,7 +1466,6 @@
        cv_destroy(&kq->kq_cv);
        seldestroy(&kq->kq_sel);
        kmem_free(kq, sizeof(*kq));
-       fp->f_data = NULL;
 
        return (0);
 }