[libvirt] [PATCH] qemu: Don't try to parse -help for new QEMU

[Peter Krempa]

On 11/12/14 17:09, Jiri Denemark wrote:
> Since QEMU 1.2.0, we switched to QMP probing instead of parsing -help
> (and other commands, such as -cpu ?) output. However, if QMP probing
> failed, we still tried starting QEMU with various options and parsing
> the output, which was guaranteed to fail because the output changed.
> Let's just refuse parsing -help for QEMU >= 1.2.0.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1160318
> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
> ---
>  src/qemu/qemu_capabilities.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index 74a3b24..bef96d5 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -1384,6 +1384,16 @@ int virQEMUCapsParseHelpStr(const char *qemu,
>  
>      *version = (major * 1000 * 1000) + (minor * 1000) + micro;
>  
> +    /* Refuse to parse -help output for QEMU releases >= 1.2.0 that should be
> +     * using QMP probing.
> +     */
> +    if (*version > 1002000) {
> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                       _("QEMU %u.%u.%u is too new for help parsing"),
> +                       major, minor, micro);
> +        goto cleanup;
> +    }
> +
>      if (virQEMUCapsComputeCmdFlags(help, *version, *is_kvm, *kvm_version,
>                                     qemuCaps, check_yajl) < 0)
>          goto cleanup;
> 

ACK, although I think that one of the steps that lead to fixing the
issue for the reporter was to purge the caps cache. As I've heard/seen
that happening we might want to check the code that checks the validity
of the cache.

Peter


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