[libvirt] [PATCH] qemu: fix a crash when save file can't be opened

[Eric Blake]

> In qemuDomainSaveMemory, wrapperFd might be NULL and should be
> checked before
> calling virFileWrapperFdCatchError. Same in doCoreDump.
> 
> Bug: https://bugzilla.redhat.com/show_bug.cgi?id=880919
> ---
>  src/qemu/qemu_driver.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index c526f5f..7892293 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -2906,7 +2906,8 @@ qemuDomainSaveMemory(struct qemud_driver
> *driver,
>  
>  cleanup:
>      VIR_FORCE_CLOSE(fd);
> -    virFileWrapperFdCatchError(wrapperFd);
> +    if (wrapperFd)
> +        virFileWrapperFdCatchError(wrapperFd);

Wouldn't it instead be easier to fix virFileWrapperFdCatchError()
to tolerate incoming NULL (meaning there is no error to catch)
than to adjust every caller?