[libvirt] [PATCH 4/4] util: fix removal of callbacks in virCloseCallbacksRun

[Ján Tomko]

On Mon, Mar 30, 2015 at 01:41:01PM +1100, Michael Chapman wrote:
> The close callbacks hash are keyed by a UUID-string, but
> virCloseCallbacksRun was attempting to remove them by raw UUID. This
> patch ensures the callback entries are removed by UUID-string as well.
> 
> This bug could cause problems when guest migrations were abnormally aborted:
> 
>   # timeout --signal KILL 1 \
>       virsh migrate example qemu+tls://remote/system \
>         --verbose --compressed --live --auto-converge \
>         --abort-on-error --unsafe --persistent \
>         --undefinesource --copy-storage-all --xml example.xml
>   Killed
> 
>   # virsh migrate example qemu+tls://remote/system \
>       --verbose --compressed --live --auto-converge \
>       --abort-on-error --unsafe --persistent \
>       --undefinesource --copy-storage-all --xml example.xml
>   error: Requested operation is not valid: domain 'example' is not being migrated
> 
> Signed-off-by: Michael Chapman <mike at very.puzzling.org>
> ---
>  src/util/virclosecallbacks.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/src/util/virclosecallbacks.c b/src/util/virclosecallbacks.c
> index 4128057..b0a1a9e 100644
> --- a/src/util/virclosecallbacks.c
> +++ b/src/util/virclosecallbacks.c
> @@ -236,6 +236,7 @@ typedef struct _virCloseCallbacksListEntry virCloseCallbacksListEntry;
>  typedef virCloseCallbacksListEntry *virCloseCallbacksListEntryPtr;
>  struct _virCloseCallbacksListEntry {
>      unsigned char uuid[VIR_UUID_BUFLEN];
> +    char uuidstr[VIR_UUID_STRING_BUFLEN];

We shouldn't be storing the uuid twice.

>      virCloseCallback callback;
>  };
>  
> @@ -279,6 +280,8 @@ virCloseCallbacksGetOne(void *payload,
>  
>      memcpy(data->list->entries[data->list->nentries - 1].uuid,
>             uuid, VIR_UUID_BUFLEN);
> +    memcpy(data->list->entries[data->list->nentries - 1].uuidstr,
> +           uuidstr, VIR_UUID_STRING_BUFLEN);
>      data->list->entries[data->list->nentries - 1].callback = closeDef->cb;
>  }
>  
> @@ -332,7 +335,7 @@ virCloseCallbacksRun(virCloseCallbacksPtr closeCallbacks,
>  
>      for (i = 0; i < list->nentries; i++) {
>          virHashRemoveEntry(closeCallbacks->list,
> -                           list->entries[i].uuid);
> +                           list->entries[i].uuidstr);

I think the CPU time wasted by doing virUUIDFormat here again is
negligible and easier than writing a Hash function that works on
VIR_UUID buffers :)

Jan
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