hmp: Implement qom-get HMP command

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>
Message-Id: <20200520151108.160598-2-dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 7f0f3974ad908fb8e2bb965b3c85146330ab73f5..250ddae54d7d9eea6a829e342e0bc06edba3e1be 100644 (file)
--- 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 e33ca5a911a5e5145e10ad4ea519906527c58666..c986cfd28bc33ddb7d8df19526d69a2fb63d49c3 100644 (file)
--- 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 cd08233a4cfe882a1e2de880a1e27bdd4fffdb2c..a8b0a080c740514966c55d79d6cb937e01fc3231 100644 (file)
--- 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);
+    }
+
+    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 f8aa5f92c5d714bfeed973b7b2427f482eecb8dc..b8b1271b9e73e87a8b1a6eb05d46f154e6dea617 100644 (file)
--- 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",