[libvirt] [PATCH 2/8] Add qemuMonitorGetObjectProperty() method for QMP qom-get command

[Michal Privoznik]

On 02.07.2013 15:39, John Ferlan wrote:
> Add a new qemuMonitorGetObjectProperty() method to support invocation
> of the 'qom-get' JSON monitor command with a provided path, property, and
> expected data type return.  The qemuMonitorObjectProperty is similar to
> virTypedParameter; however, a future patch will extend it a bit to include
> a void pointer to balloon driver statistic data.
> 
> The provided test will execute a qom-get on "/machine/i440fx" which will
> return a property "realized".
> ---
>  src/qemu/qemu_monitor.c      | 23 ++++++++++++
>  src/qemu/qemu_monitor.h      | 33 +++++++++++++++++
>  src/qemu/qemu_monitor_json.c | 86 ++++++++++++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_monitor_json.h |  6 ++++
>  tests/qemumonitorjsontest.c  | 48 +++++++++++++++++++++++++
>  5 files changed, 196 insertions(+)
> 
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index f175250..6737a63 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -3468,6 +3468,29 @@ void qemuMonitorListPathFree(qemuMonitorListPathPtr paths)
>  }
>  
>  
> +int qemuMonitorGetObjectProperty(qemuMonitorPtr mon,
> +                                 const char *path,
> +                                 const char *property,
> +                                 qemuMonitorObjectPropertyPtr prop)
> +{
> +    VIR_DEBUG("mon=%p path=%s property=%s prop=%p type=%d",
> +              mon, path, property, prop, prop->type);
> +    if (!mon) {
> +        virReportError(VIR_ERR_INVALID_ARG, "%s",
> +                       _("monitor must not be NULL"));
> +        return -1;
> +    }
> +
> +    if (!mon->json) {
> +        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
> +                       _("JSON monitor is required"));
> +        return -1;
> +    }
> +
> +    return qemuMonitorJSONGetObjectProperty(mon, path, property, prop);
> +}
> +
> +
>  int qemuMonitorGetObjectProps(qemuMonitorPtr mon,
>                                const char *type,
>                                char ***props)
> diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
> index 2e92f8c..cc22123 100644
> --- a/src/qemu/qemu_monitor.h
> +++ b/src/qemu/qemu_monitor.h
> @@ -694,6 +694,39 @@ int qemuMonitorGetObjectListPaths(qemuMonitorPtr mon,
>  
>  void qemuMonitorListPathFree(qemuMonitorListPathPtr paths);
>  
> +/* Flags for the 'type' field in _qemuMonitorObjectProperty */
> +typedef enum {
> +    QEMU_MONITOR_OBJECT_PROPERTY_BOOLEAN=1,
> +    QEMU_MONITOR_OBJECT_PROPERTY_INT,
> +    QEMU_MONITOR_OBJECT_PROPERTY_LONG,
> +    QEMU_MONITOR_OBJECT_PROPERTY_UINT,
> +    QEMU_MONITOR_OBJECT_PROPERTY_ULONG,
> +    QEMU_MONITOR_OBJECT_PROPERTY_DOUBLE,
> +    QEMU_MONITOR_OBJECT_PROPERTY_STRING,
> +
> +    QEMU_MONITOR_OBJECT_PROPERTY_LAST
> +} qemuMonitorObjectPropertyType;
> +
> +typedef struct _qemuMonitorObjectProperty qemuMonitorObjectProperty;
> +typedef qemuMonitorObjectProperty *qemuMonitorObjectPropertyPtr;
> +struct _qemuMonitorObjectProperty {
> +    int type;    /* qemuMonitorObjectPropertyType */
> +    union {
> +        bool b;
> +        int i;
> +        long long l;
> +        unsigned int ui;
> +        unsigned long long ul;
> +        double d;
> +        char *str;
> +    } val;
> +};
> +
> +int qemuMonitorGetObjectProperty(qemuMonitorPtr mon,
> +                                 const char *path,
> +                                 const char *property,
> +                                 qemuMonitorObjectPropertyPtr prop);
> +
>  int qemuMonitorGetObjectProps(qemuMonitorPtr mon,
>                                const char *type,
>                                char ***props);
> diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
> index 7d0cc85..a725903 100644
> --- a/src/qemu/qemu_monitor_json.c
> +++ b/src/qemu/qemu_monitor_json.c
> @@ -4626,6 +4626,92 @@ cleanup:
>      return ret;
>  }
>  
> +
> +int qemuMonitorJSONGetObjectProperty(qemuMonitorPtr mon,
> +                                     const char *path,
> +                                     const char *property,
> +                                     qemuMonitorObjectPropertyPtr prop)
> +{
> +    int ret;
> +    virJSONValuePtr cmd;
> +    virJSONValuePtr reply = NULL;
> +    virJSONValuePtr data;
> +    const char *tmp;
> +
> +    if (!(cmd = qemuMonitorJSONMakeCommand("qom-get",
> +                                           "s:path", path,
> +                                           "s:property", property,
> +                                           NULL)))
> +        return -1;
> +
> +    ret = qemuMonitorJSONCommand(mon, cmd, &reply);
> +
> +    if (ret == 0)
> +        ret = qemuMonitorJSONCheckError(cmd, reply);
> +
> +    if (ret < 0)
> +        goto cleanup;
> +
> +    ret = -1;
> +
> +    if (!(data = virJSONValueObjectGet(reply, "return"))) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("qom-get reply was missing return data"));
> +        goto cleanup;
> +    }
> +
> +    switch (prop->type) {
> +    /* Simple cases of boolean, int, long, uint, ulong, double, and string
> +     * will receive return value as part of {"return": xxx} statement
> +     */
> +    case QEMU_MONITOR_OBJECT_PROPERTY_BOOLEAN:
> +        ret = virJSONValueGetBoolean(data, &prop->val.b);
> +        break;
> +    case QEMU_MONITOR_OBJECT_PROPERTY_INT:
> +        ret = virJSONValueGetNumberInt(data, &prop->val.i);
> +        break;
> +    case QEMU_MONITOR_OBJECT_PROPERTY_LONG:
> +        ret = virJSONValueGetNumberLong(data, &prop->val.l);
> +        break;
> +    case QEMU_MONITOR_OBJECT_PROPERTY_UINT:
> +        ret = virJSONValueGetNumberUint(data, &prop->val.ui);
> +        break;
> +    case QEMU_MONITOR_OBJECT_PROPERTY_ULONG:
> +        ret = virJSONValueGetNumberUlong(data, &prop->val.ul);
> +        break;
> +    case QEMU_MONITOR_OBJECT_PROPERTY_DOUBLE:
> +        ret = virJSONValueGetNumberDouble(data, &prop->val.d);
> +        break;
> +    case QEMU_MONITOR_OBJECT_PROPERTY_STRING:
> +        tmp = virJSONValueGetString(data);
> +        if (tmp && VIR_STRDUP(prop->val.str, tmp) < 0)

Lose the 'tmp' here as VIR_STRDUP will check it for NULL anyway. In
fact, these lines can be rewritten into a single line:

ret = VIR_STRDUP(prop->val.str, tmp);

> +            goto cleanup;
> +        if (tmp)
> +            ret = 0;
> +        break;
> +    case QEMU_MONITOR_OBJECT_PROPERTY_LAST:
> +    default:
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("qom-get invalid object property type %d"),
> +                       prop->type);
> +        goto cleanup;
> +    }
> +
> +    if (ret == -1) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("qom-get reply was missing return data"));
> +        goto cleanup;
> +    }
> +
> +    ret = 0;
> +cleanup:
> +    virJSONValueFree(cmd);
> +    virJSONValueFree(reply);
> +
> +    return ret;
> +}
> +
> +

Michal