qdev: Fix exit code for -device ?

Help was shoehorned into device creation, qdev_device_add().  Since
help doesn't create a device, it returns NULL, which looks to callers
just like failed device creation.  Monitor handler do_device_add()
doesn't care, but main() exits unsuccessfully.

Move help out of device creation, into new qdev_device_help().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

2 files changed, 20 insertions, 9 deletions

diff --git a/hw/qdev.c b/hw/qdev.c
index c64357603d..f47f0cb973 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -153,6 +153,24 @@ static int set_property(const char *name, const char *value, void *opaque)
     return 0;
 }
 
+int qdev_device_help(QemuOpts *opts)
+{
+    const char *driver;
+    DeviceInfo *info;
+    char msg[256];
+
+    driver = qemu_opt_get(opts, "driver");
+    if (driver && !strcmp(driver, "?")) {
+        for (info = device_info_list; info != NULL; info = info->next) {
+            qdev_print_devinfo(info, msg, sizeof(msg));
+            qemu_error("%s\n", msg);
+        }
+        return 1;
+    }
+
+    return 0;
+}
+
 DeviceState *qdev_device_add(QemuOpts *opts)
 {
     const char *driver, *path, *id;
@@ -165,14 +183,6 @@ DeviceState *qdev_device_add(QemuOpts *opts)
         qemu_error("-device: no driver specified\n");
         return NULL;
     }
-    if (strcmp(driver, "?") == 0) {
-        char msg[256];
-        for (info = device_info_list; info != NULL; info = info->next) {
-            qdev_print_devinfo(info, msg, sizeof(msg));
-            qemu_error("%s\n", msg);
-        }
-        return NULL;
-    }
 
     /* find driver */
     info = qdev_find_info(NULL, driver);
@@ -726,7 +736,7 @@ void do_device_add(Monitor *mon, const QDict *qdict)
 
     opts = qemu_opts_parse(&qemu_device_opts,
                            qdict_get_str(qdict, "config"), "driver");
-    if (opts)
+    if (opts && !qdev_device_help(opts))
         qdev_device_add(opts);
 }
 
diff --git a/hw/qdev.h b/hw/qdev.h
index 07b9603804..0eb45b0476 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -104,6 +104,7 @@ typedef struct GlobalProperty {
 /*** Board API.  This should go away once we have a machine config file.  ***/
 
 DeviceState *qdev_create(BusState *bus, const char *name);
+int qdev_device_help(QemuOpts *opts);
 DeviceState *qdev_device_add(QemuOpts *opts);
 int qdev_init(DeviceState *dev) QEMU_WARN_UNUSED_RESULT;
 void qdev_init_nofail(DeviceState *dev);