[Qemu-devel] [PATCH v3 3/3] object: Add 'help' option for all available backends and properties

[Lin Ma <lma@suse.com>]

'-object help' prints available user creatable backends.
'-object $typename,help' prints relevant properties.

Signed-off-by: Lin Ma <lma@suse.com>
---
 backends/hostmem.c              |  4 ++++
 crypto/secret.c                 |  4 ++++
 crypto/tlscreds.c               |  4 ++++
 include/qom/object_interfaces.h |  2 ++
 net/filter.c                    |  4 ++++
 qemu-options.hx                 |  7 +++++-
 qom/object_interfaces.c         | 48 +++++++++++++++++++++++++++++++++++++++++
 vl.c                            |  5 +++++
 8 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/backends/hostmem.c b/backends/hostmem.c
index b7a208d..eea9dce 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -261,6 +261,10 @@ static void host_memory_backend_init(Object *obj)
                              HostMemPolicy_lookup,
                              host_memory_backend_get_policy,
                              host_memory_backend_set_policy, NULL);
+    object_property_set_description(obj, "policy",
+                                    "Data format: one of "
+                                    HostMemPolicy_value_str,
+                                    &error_abort);
 }
 
 MemoryRegion *
diff --git a/crypto/secret.c b/crypto/secret.c
index 285ab7a..71d06e3 100644
--- a/crypto/secret.c
+++ b/crypto/secret.c
@@ -382,6 +382,10 @@ qcrypto_secret_class_init(ObjectClass *oc, void *data)
                                    qcrypto_secret_prop_get_format,
                                    qcrypto_secret_prop_set_format,
                                    NULL);
+    object_class_property_set_description(oc, "format",
+                                          "Data format: one of "
+                                          QCryptoSecretFormat_value_str,
+                                          &error_abort);
     object_class_property_add_str(oc, "data",
                                   qcrypto_secret_prop_get_data,
                                   qcrypto_secret_prop_set_data,
diff --git a/crypto/tlscreds.c b/crypto/tlscreds.c
index a896553..d3af38a 100644
--- a/crypto/tlscreds.c
+++ b/crypto/tlscreds.c
@@ -237,6 +237,10 @@ qcrypto_tls_creds_class_init(ObjectClass *oc, void *data)
                                    qcrypto_tls_creds_prop_get_endpoint,
                                    qcrypto_tls_creds_prop_set_endpoint,
                                    NULL);
+    object_class_property_set_description(oc, "endpoint",
+                                          "Data format: one of "
+                                          QCryptoTLSCredsEndpoint_value_str,
+                                          &error_abort);
     object_class_property_add_str(oc, "priority",
                                   qcrypto_tls_creds_prop_get_priority,
                                   qcrypto_tls_creds_prop_set_priority,
diff --git a/include/qom/object_interfaces.h b/include/qom/object_interfaces.h
index 8b17f4d..197cd5f 100644
--- a/include/qom/object_interfaces.h
+++ b/include/qom/object_interfaces.h
@@ -165,4 +165,6 @@ int user_creatable_add_opts_foreach(void *opaque,
  */
 void user_creatable_del(const char *id, Error **errp);
 
+int user_creatable_help_func(void *opaque, QemuOpts *opts, Error **errp);
+
 #endif
diff --git a/net/filter.c b/net/filter.c
index 1dfd2ca..205fb49 100644
--- a/net/filter.c
+++ b/net/filter.c
@@ -182,6 +182,10 @@ static void netfilter_init(Object *obj)
                              NetFilterDirection_lookup,
                              netfilter_get_direction, netfilter_set_direction,
                              NULL);
+    object_property_set_description(obj, "queue",
+                                    "Data format: one of "
+                                    NetFilterDirection_value_str,
+                                    &error_abort);
     object_property_add_str(obj, "status",
                             netfilter_get_status, netfilter_set_status,
                             NULL);
diff --git a/qemu-options.hx b/qemu-options.hx
index 0b621bb..978d37b 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3759,7 +3759,9 @@ DEF("object", HAS_ARG, QEMU_OPTION_object,
     "                create a new object of type TYPENAME setting properties\n"
     "                in the order they are specified.  Note that the 'id'\n"
     "                property must be set.  These objects are placed in the\n"
-    "                '/objects' path.\n",
+    "                '/objects' path.\n"
+    "                Use '-object help' to print available backend types and\n"
+    "                '-object typename,help' to print relevant properties.\n",
     QEMU_ARCH_ALL)
 STEXI
 @item -object @var{typename}[,@var{prop1}=@var{value1},...]
@@ -3769,6 +3771,9 @@ in the order they are specified.  Note that the 'id'
 property must be set.  These objects are placed in the
 '/objects' path.
 
+Use @code{-object help} to print available backend types and
+@code{-object @var{typename},help} to print relevant properties.
+
 @table @option
 
 @item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off}
diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
index 9288242..70c1e44 100644
--- a/qom/object_interfaces.c
+++ b/qom/object_interfaces.c
@@ -5,6 +5,7 @@
 #include "qapi-visit.h"
 #include "qapi/qmp-output-visitor.h"
 #include "qapi/opts-visitor.h"
+#include "qemu/help_option.h"
 
 void user_creatable_complete(Object *obj, Error **errp)
 {
@@ -212,6 +213,53 @@ void user_creatable_del(const char *id, Error **errp)
     object_unparent(obj);
 }
 
+int user_creatable_help_func(void *opaque, QemuOpts *opts, Error **errp)
+{
+    char *type = NULL;
+    Object *obj = NULL;
+    ObjectProperty *prop;
+    ObjectPropertyIterator iter;
+
+    type = qemu_opt_get(opts, "qom-type");
+    if (type && is_help_option(type)) {
+        GSList *list;
+        printf("Available object backend types:\n");
+        for (list = object_class_get_list(TYPE_USER_CREATABLE, false);  \
+                list;                                                   \
+                list = list->next) {
+            const char *name;
+            name = object_class_get_name(OBJECT_CLASS(list->data));
+            printf("%s\n", name);
+        }
+        g_slist_free(list);
+        goto out;
+    }
+
+    if (!type || !qemu_opt_has_help_opt(opts)) {
+        return 0;
+    }
+
+    if (!object_class_by_name(type)) {
+        printf("invalid object type: %s\n", type);
+        goto out;
+    }
+    obj = object_new(type);
+    object_property_iter_init(&iter, obj);
+
+    while ((prop = object_property_iter_next(&iter))) {
+        if (prop->description) {
+            printf("%s (%s, %s)\n", prop->name, prop->type, prop->description);
+        } else {
+            printf("%s (%s)\n", prop->name, prop->type);
+        }
+    }
+
+out:
+    g_free(type);
+    object_unref(obj);
+    return 1;
+}
+
 static void register_types(void)
 {
     static const TypeInfo uc_interface_info = {
diff --git a/vl.c b/vl.c
index 215a6f9..c5ce7ea 100644
--- a/vl.c
+++ b/vl.c
@@ -4090,6 +4090,11 @@ int main(int argc, char **argv, char **envp)
         exit(0);
     }
 
+    if (qemu_opts_foreach(qemu_find_opts("object"), user_creatable_help_func,
+                          NULL, NULL)) {
+        exit(1);
+    }
+
     if (!trace_init_backends()) {
         exit(1);
     }
-- 
2.9.2