Re: [PATCH 1/2] hmp: Implement qom-get HMP command

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 5/20/20 5:11 PM, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> This started off as Andreas Färber's implementation from
> March 2015, but after feedback from Paolo and Markus it morphed into
> using the json output which handles structs reasonably.
> 
> Use with qom-list to find the members of an object.
> 
> (qemu) qom-get /backend/console[0]/device/vga.rom[0] size
> 65536
> (qemu) qom-get /machine smm
> "auto"
> (qemu) qom-get /machine rtc-time
> {
>      "tm_year": 120,
>      "tm_sec": 51,
>      "tm_hour": 9,
>      "tm_min": 50,
>      "tm_mon": 4,
>      "tm_mday": 20
> }
> (qemu) qom-get /machine frob
> Error: Property '.frob' not found
> 
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>   hmp-commands.hx        | 14 ++++++++++++++
>   include/monitor/hmp.h  |  1 +
>   qom/qom-hmp-cmds.c     | 18 ++++++++++++++++++
>   tests/qtest/test-hmp.c |  1 +
>   4 files changed, 34 insertions(+)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 7f0f3974ad..250ddae54d 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1790,6 +1790,20 @@ SRST
>     Print QOM properties of object at location *path*
>   ERST
>   
> +    {
> +        .name       = "qom-get",
> +        .args_type  = "path:s,property:s",
> +        .params     = "path property",
> +        .help       = "print QOM property",
> +        .cmd        = hmp_qom_get,
> +        .flags      = "p",
> +    },
> +
> +SRST
> +``qom-get`` *path* *property*
> +  Print QOM property *property* of object at location *path*
> +ERST
> +
>       {
>           .name       = "qom-set",
>           .args_type  = "path:s,property:s,value:s",
> diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
> index e33ca5a911..c986cfd28b 100644
> --- a/include/monitor/hmp.h
> +++ b/include/monitor/hmp.h
> @@ -96,6 +96,7 @@ void hmp_info_memdev(Monitor *mon, const QDict *qdict);
>   void hmp_info_numa(Monitor *mon, const QDict *qdict);
>   void hmp_info_memory_devices(Monitor *mon, const QDict *qdict);
>   void hmp_qom_list(Monitor *mon, const QDict *qdict);
> +void hmp_qom_get(Monitor *mon, const QDict *qdict);
>   void hmp_qom_set(Monitor *mon, const QDict *qdict);
>   void hmp_info_qom_tree(Monitor *mon, const QDict *dict);
>   void object_add_completion(ReadLineState *rs, int nb_args, const char *str);
> diff --git a/qom/qom-hmp-cmds.c b/qom/qom-hmp-cmds.c
> index cd08233a4c..a8b0a080c7 100644
> --- a/qom/qom-hmp-cmds.c
> +++ b/qom/qom-hmp-cmds.c
> @@ -12,6 +12,8 @@
>   #include "qapi/error.h"
>   #include "qapi/qapi-commands-qom.h"
>   #include "qapi/qmp/qdict.h"
> +#include "qapi/qmp/qjson.h"
> +#include "qapi/qmp/qstring.h"
>   #include "qom/object.h"
>   
>   void hmp_qom_list(Monitor *mon, const QDict *qdict)
> @@ -62,6 +64,22 @@ void hmp_qom_set(Monitor *mon, const QDict *qdict)
>       hmp_handle_error(mon, err);
>   }
>   
> +void hmp_qom_get(Monitor *mon, const QDict *qdict)
> +{
> +    const char *path = qdict_get_str(qdict, "path");
> +    const char *property = qdict_get_str(qdict, "property");
> +    Error *err = NULL;
> +    QObject *obj = qmp_qom_get(path, property, &err);
> +
> +    if (err == NULL) {
> +        QString *str = qobject_to_json_pretty(obj);
> +        monitor_printf(mon, "%s\n", qstring_get_str(str));
> +        qobject_unref(str);

Simple, does the job, lovely!

> +    }
> +
> +    hmp_handle_error(mon, err);
> +}
> +
>   typedef struct QOMCompositionState {
>       Monitor *mon;
>       int indent;
> diff --git a/tests/qtest/test-hmp.c b/tests/qtest/test-hmp.c
> index f8aa5f92c5..b8b1271b9e 100644
> --- a/tests/qtest/test-hmp.c
> +++ b/tests/qtest/test-hmp.c
> @@ -61,6 +61,7 @@ static const char *hmp_cmds[] = {
>       "p $pc + 8",
>       "qom-list /",
>       "qom-set /machine initrd test",
> +    "qom-get /machine initrd",
>       "screendump /dev/null",
>       "sendkey x",
>       "singlestep on",
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>