[Qemu-devel] [PATCH] qom: enforce readonly nature of link's check callback

[Igor Mammedov]

link's check callback is supposed to verify/permit setting it,
however currently nothing restricts it from misusing it
and modifying target object from within.
Make sure that readonly semantics are checked by compiler
to prevent callback's misuse.

Signed-off-by: Igor Mammedov <address@hidden>
---
Fam,
 it probably conflicts with yours DEFINE_PROP_LINK series,
 feel free to include this patch if you'll have to respin

---
 include/hw/qdev-properties.h | 3 ++-
 include/qom/object.h         | 6 +++---
 hw/core/qdev-properties.c    | 3 ++-
 hw/display/xlnx_dp.c         | 2 +-
 hw/ipmi/ipmi.c               | 2 +-
 hw/mem/pc-dimm.c             | 2 +-
 hw/misc/ivshmem.c            | 2 +-
 qom/object.c                 | 8 ++++----
 8 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
index 306bbab..6dfe16e 100644
--- a/include/hw/qdev-properties.h
+++ b/include/hw/qdev-properties.h
@@ -234,7 +234,8 @@ void qdev_prop_set_after_realize(DeviceState *dev, const 
char *name,
  * This function should be used as the check() argument to
  * object_property_add_link().
  */
-void qdev_prop_allow_set_link_before_realize(Object *obj, const char *name,
+void qdev_prop_allow_set_link_before_realize(const Object *obj,
+                                             const char *name,
                                              Object *val, Error **errp);
 
 #endif
diff --git a/include/qom/object.h b/include/qom/object.h
index 5ecc2d1..5223692 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -788,7 +788,7 @@ ObjectClass *object_get_class(Object *obj);
  *
  * Returns: The QOM typename of @obj.
  */
-const char *object_get_typename(Object *obj);
+const char *object_get_typename(const Object *obj);
 
 /**
  * type_register_static:
@@ -1320,7 +1320,7 @@ typedef enum {
  * callback function.  It allows the link property to be set and never returns
  * an error.
  */
-void object_property_allow_set_link(Object *, const char *,
+void object_property_allow_set_link(const Object *, const char *,
                                     Object *, Error **);
 
 /**
@@ -1353,7 +1353,7 @@ void object_property_allow_set_link(Object *, const char 
*,
  */
 void object_property_add_link(Object *obj, const char *name,
                               const char *type, Object **child,
-                              void (*check)(Object *obj, const char *name,
+                              void (*check)(const Object *obj, const char 
*name,
                                             Object *val, Error **errp),
                               ObjectPropertyLinkFlags flags,
                               Error **errp);
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index 2a82768..95e5fdb 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -25,7 +25,8 @@ void qdev_prop_set_after_realize(DeviceState *dev, const char 
*name,
     }
 }
 
-void qdev_prop_allow_set_link_before_realize(Object *obj, const char *name,
+void qdev_prop_allow_set_link_before_realize(const Object *obj,
+                                             const char *name,
                                              Object *val, Error **errp)
 {
     DeviceState *dev = DEVICE(obj);
diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
index f43eb09..3ed81ff 100644
--- a/hw/display/xlnx_dp.c
+++ b/hw/display/xlnx_dp.c
@@ -515,7 +515,7 @@ static void xlnx_dp_aux_set_command(XlnxDPState *s, 
uint32_t value)
     s->core_registers[DP_INTERRUPT_SIGNAL_STATE] |= 0x04;
 }
 
-static void xlnx_dp_set_dpdma(Object *obj, const char *name, Object *val,
+static void xlnx_dp_set_dpdma(const Object *obj, const char *name, Object *val,
                               Error **errp)
 {
     XlnxDPState *s = XLNX_DP(obj);
diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
index 5cf1caa..a2fd1eb 100644
--- a/hw/ipmi/ipmi.c
+++ b/hw/ipmi/ipmi.c
@@ -90,7 +90,7 @@ static TypeInfo ipmi_interface_type_info = {
     .class_init = ipmi_interface_class_init,
 };
 
-static void isa_ipmi_bmc_check(Object *obj, const char *name,
+static void isa_ipmi_bmc_check(const Object *obj, const char *name,
                                Object *val, Error **errp)
 {
     IPMIBmc *bmc = IPMI_BMC(val);
diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index 9e8dab0..380cb30 100644
--- a/hw/mem/pc-dimm.c
+++ b/hw/mem/pc-dimm.c
@@ -366,7 +366,7 @@ static void pc_dimm_get_size(Object *obj, Visitor *v, const 
char *name,
     visit_type_int(v, name, &value, errp);
 }
 
-static void pc_dimm_check_memdev_is_busy(Object *obj, const char *name,
+static void pc_dimm_check_memdev_is_busy(const Object *obj, const char *name,
                                       Object *val, Error **errp)
 {
     Error *local_err = NULL;
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index abeaf3d..e25016c 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -1005,7 +1005,7 @@ static const TypeInfo ivshmem_common_info = {
     .class_init    = ivshmem_common_class_init,
 };
 
-static void ivshmem_check_memdev_is_busy(Object *obj, const char *name,
+static void ivshmem_check_memdev_is_busy(const Object *obj, const char *name,
                                          Object *val, Error **errp)
 {
     if (host_memory_backend_is_mapped(MEMORY_BACKEND(val))) {
diff --git a/qom/object.c b/qom/object.c
index 7a05e35..a429e64 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -735,7 +735,7 @@ out:
     return ret;
 }
 
-const char *object_get_typename(Object *obj)
+const char *object_get_typename(const Object *obj)
 {
     return obj->class->type->name;
 }
@@ -1395,7 +1395,7 @@ out:
     g_free(type);
 }
 
-void object_property_allow_set_link(Object *obj, const char *name,
+void object_property_allow_set_link(const Object *obj, const char *name,
                                     Object *val, Error **errp)
 {
     /* Allow the link to be set, always */
@@ -1403,7 +1403,7 @@ void object_property_allow_set_link(Object *obj, const 
char *name,
 
 typedef struct {
     Object **child;
-    void (*check)(Object *, const char *, Object *, Error **);
+    void (*check)(const Object *, const char *, Object *, Error **);
     ObjectPropertyLinkFlags flags;
 } LinkProperty;
 
@@ -1519,7 +1519,7 @@ static void object_release_link_property(Object *obj, 
const char *name,
 
 void object_property_add_link(Object *obj, const char *name,
                               const char *type, Object **child,
-                              void (*check)(Object *, const char *,
+                              void (*check)(const Object *, const char *,
                                             Object *, Error **),
                               ObjectPropertyLinkFlags flags,
                               Error **errp)
-- 
2.7.4