Attachment 129821 Details for Bug 88808 – dbus-socket-set-epoll: initialize all bytes of struct epoll_event

[patch] dbus-socket-set-epoll: initialize all bytes of struct epoll_event

dbus-socket-set-epoll-initialize-all-bytes-of-stru.patch (text/plain), 2.13 KB, created by Philip Withnall on 2017-02-22 10:58:54 UTC

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Creator: Philip Withnall

Created: 2017-02-22 10:58:54 UTC

Size: 2.13 KB

patch

obsolete

>From 1be4b9bd156d6e0ac4849b6d71ad4c66f9d7f8ce Mon Sep 17 00:00:00 2001
>From: Simon McVittie <simon.mcvittie@collabora.co.uk>
>Date: Thu, 22 Jan 2015 20:11:07 +0000
>Subject: [PATCH] dbus-socket-set-epoll: initialize all bytes of struct
> epoll_event
>
>This should be a no-op, but it shuts Valgrind up.
>
>The reason for the warning is that we fill in event.events and
>event.data.fd, but the union event.data actually contains more bytes
>than that. We'll get the same partially initialized union back from the
>kernel in socket_set_epoll_poll(), where we take events[i].data.fd and
>ignore the rest. So the current code is safe, but valgrind is right to
>worry.
>
>https://bugs.freedesktop.org/show_bug.cgi?id=88808
>---
> dbus/dbus-socket-set-epoll.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
>diff --git a/dbus/dbus-socket-set-epoll.c b/dbus/dbus-socket-set-epoll.c
>index 5bd8d5a..4692cbe 100644
>--- a/dbus/dbus-socket-set-epoll.c
>+++ b/dbus/dbus-socket-set-epoll.c
>@@ -144,6 +144,7 @@ socket_set_epoll_add (DBusSocketSet  *set,
>   struct epoll_event event;
>   int err;
> 
>+  _DBUS_ZERO (event);
>   event.data.fd = fd;
> 
>   if (enabled)
>@@ -196,6 +197,7 @@ socket_set_epoll_enable (DBusSocketSet  *set,
>   struct epoll_event event;
>   int err;
> 
>+  _DBUS_ZERO (event);
>   event.data.fd = fd;
>   event.events = watch_flags_to_epoll_events (flags);
> 
>@@ -251,6 +253,7 @@ socket_set_epoll_disable (DBusSocketSet  *set,
>    * work on 2.6.32). Compile this file with -DTEST_BEHAVIOUR_OF_EPOLLET for
>    * test code.
>    */
>+  _DBUS_ZERO (event);
>   event.data.fd = fd;
>   event.events = EPOLLET;
> 
>@@ -270,7 +273,8 @@ socket_set_epoll_remove (DBusSocketSet  *set,
>   int err;
>   /* Kernels < 2.6.9 require a non-NULL struct pointer, even though its
>    * contents are ignored */
>-  struct epoll_event dummy = { 0 };
>+  struct epoll_event dummy;
>+  _DBUS_ZERO (dummy);
> 
>   if (epoll_ctl (self->epfd, EPOLL_CTL_DEL, fd, &dummy) == 0)
>     return;
>@@ -346,6 +350,8 @@ main (void)
>   int fd = 0; /* stdin */
>   int ret;
> 
>+  _DBUS_ZERO (input);
>+
>   input.events = EPOLLHUP | EPOLLET;
>   ret = epoll_ctl (epfd, EPOLL_CTL_ADD, fd, &input);
>   printf ("ctl ADD: %d\n", ret);
>-- 
>2.9.3

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Attachments on bug 88808: 112837 | 112838 | 112839 | 112840 | 129821

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