Re: [libvirt] [PATCH] umlAutostartDomain: avoid NULL-deref upon virGetLastError failure
Eric Blake wrote:
On 05/17/2010 06:38 AM, Jim Meyering wrote:
> Another...
>
>>From 09579adb73f04c5b940ad28cdfc242cff0726e0e Mon Sep 17 00:00:00 2001
> From: Jim Meyering <meyering(a)redhat.com>
> Date: Mon, 17 May 2010 14:38:14 +0200
> Subject: [PATCH] umlAutostartDomain: avoid NULL-deref upon virGetLastError failure
>
> * src/uml/uml_driver.c (umlAutostartDomain): Handle a NULL return
> from virGetLastError.
> ---
> src/uml/uml_driver.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/src/uml/uml_driver.c b/src/uml/uml_driver.c
> index 63fe808..ffb87c8 100644
> --- a/src/uml/uml_driver.c
> +++ b/src/uml/uml_driver.c
> @@ -157,7 +157,7 @@ umlAutostartDomain(void *payload, const char *name
ATTRIBUTE_UNUSED, void *opaqu
> if (umlStartVMDaemon(data->conn, data->driver, vm) < 0) {
> virErrorPtr err = virGetLastError();
> VIR_ERROR(_("Failed to autostart VM '%s': %s"),
> - vm->def->name, err->message);
> + vm->def->name, err ? err->message : "");
That looks awkward to end with a trailing space. Might it be better to use:
err ? err->message : _("unknown reason")
At any rate, ACK that this fixes a potential NULL deref.
That's a good point.
I considered going one step further and changing
virGetLastError so that it never returns NULL,
instead returning a pointer to a static buffer where
err->message is something like "internal failure".
Otherwise, many uses of virGetLastError have to use the
same awkward idiom:
err ? err->message : "..."
If no one objects to such a change, I'll add it to my low-priority list.