Re: [libvirt] [PATCH] uml_conf.c: don't return an uninitialized pointer
Daniel P. Berrange wrote:
On Thu, Sep 03, 2009 at 12:07:14PM +0200, Jim Meyering wrote:
> Another "real" bug:
>
> >From 6697607bf0b023ffb692576b31d652d10719b08a Mon Sep 17 00:00:00 2001
> From: Jim Meyering <meyering(a)redhat.com>
> Date: Thu, 3 Sep 2009 12:05:52 +0200
> Subject: [PATCH] uml_conf.c: don't return an uninitialized pointer
>
> * src/uml_conf.c (umlBuildCommandLineChr): Initialize "ret" also
> in the final switch cases.
> ---
> src/uml_conf.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/src/uml_conf.c b/src/uml_conf.c
> index 838fedd..2e9c25c 100644
> --- a/src/uml_conf.c
> +++ b/src/uml_conf.c
> @@ -331,6 +331,7 @@ umlBuildCommandLineChr(virConnectPtr conn,
> default:
> umlReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
> _("unsupported chr device type %d"),
def->type);
> + ret = NULL;
> break;
> }
I think this would be better changing the initial declartion to be
initializing to NULL too.
Actually I did that first, but then un-did it in favor
of the change above. Why? because that initialization could
mask a failure to initialize in a new case.
With per-case initialization, we'd detect the bug at
compile/static-analysis time. With the up-front unconditional
initialization, we cannot, and would have to rely on testing to find it.