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Date: Wed, 5 Feb 2014 21:59:14 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20140205195914.GA8017@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] pc.c: better error message on initrd
 sizing failure
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Andreas =?iso-8859-1?Q?F=E4rber?= <afaerber@suse.de>, QEMU Developers <qemu-devel@nongnu.org>, Anthony Liguori <aliguori@amazon.com>, Igor Mammedov <imammedo@redhat.com>

On Sun, Feb 02, 2014 at 08:46:35PM +0000, Peter Maydell wrote:
> On 2 February 2014 20:46, Michael S. Tsirkin <mst@redhat.com> wrote:
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  hw/i386/pc.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> > index 348b15f..e715a33 100644
> > --- a/hw/i386/pc.c
> > +++ b/hw/i386/pc.c
> > @@ -835,8 +835,8 @@ static void load_linux(FWCfgState *fw_cfg,
> >
> >          initrd_size = get_image_size(initrd_filename);
> >          if (initrd_size < 0) {
> > -            fprintf(stderr, "qemu: error reading initrd %s\n",
> > -                    initrd_filename);
> > +            fprintf(stderr, "qemu: error reading initrd %s: %s\n",
> > +                    initrd_filename, strerror(errno));
> >              exit(1);
> 
> get_image_size() happens to set errno on failure, but it
> doesn't guarantee to -- all the doc comment says currently
> is "return the size or -1 if error". If we're going to rely on
> errno being set in the failure case it would be nice to at
> least add an "(and errno is set)" to that. (Better still would
> be to transfer the info into a properly formatted doc comment
> for the prototype in include/hw/loader.h...)
> 
> thanks
> -- PMM

Good idea. This patch doesn't have to change though - I'll post
an additional one with the comment.