[PATCH 2/2] qemu: monitor: Make qemuMonitorAddObject more robust against programming errors

[Peter Krempa <pkrempa@xxxxxxxxxx>]

Document and check that @props contains a pointer to a json object and
check that both necessary fields are present. Also marm @props as
NONNULL.

Signed-off-by: Peter Krempa <pkrempa@xxxxxxxxxx>
---
 src/qemu/qemu_monitor.c | 22 ++++++++++++++++------
 src/qemu/qemu_monitor.h |  3 ++-
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 6ed475ede0..c1afe21cc1 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -3073,8 +3073,9 @@ qemuMonitorCreateObjectProps(virJSONValuePtr *propsret,
 /**
  * qemuMonitorAddObject:
  * @mon: Pointer to monitor object
- * @props: Optional arguments for the given type. The object is consumed and
- *         the pointer is cleared.
+ * @props: Pointer to a JSON object holding configuration of the object to add.
+ *         The object must be non-null and contain at least the "qom-type" and
+ *         "id" field. The object is consumed and the pointer is cleared.
  * @alias: If not NULL, returns the alias of the added object if it was added
  *         successfully to qemu. Caller should free the returned pointer.
  *
@@ -3085,18 +3086,27 @@ qemuMonitorAddObject(qemuMonitorPtr mon,
                      virJSONValuePtr *props,
                      char **alias)
 {
-    const char *type = virJSONValueObjectGetString(*props, "qom-type");
-    const char *id = virJSONValueObjectGetString(*props, "id");
+    const char *type = NULL;
+    const char *id = NULL;
     char *tmp = NULL;
     int ret = -1;

+    if (!*props) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, _("object props can't be NULL"));
+        goto cleanup;
+    }
+
+    type = virJSONValueObjectGetString(*props, "qom-type");
+    id = virJSONValueObjectGetString(*props, "id");
+
     VIR_DEBUG("type=%s id=%s", NULLSTR(type), NULLSTR(id));

     QEMU_CHECK_MONITOR_GOTO(mon, cleanup);

-    if (!id) {
+    if (!id || !type) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("missing alias for qemu object '%s'"), NULLSTR(type));
+                       _("missing alias or qom-type for qemu object '%s'"),
+                       NULLSTR(type));
         goto cleanup;
     }

diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index b3d62324b4..e8adda8aa0 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -812,7 +812,8 @@ int qemuMonitorCreateObjectProps(virJSONValuePtr *propsret,

 int qemuMonitorAddObject(qemuMonitorPtr mon,
                          virJSONValuePtr *props,
-                         char **alias);
+                         char **alias)
+    ATTRIBUTE_NONNULL(1);

 int qemuMonitorDelObject(qemuMonitorPtr mon,
                          const char *objalias);
-- 
2.16.2

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