maint: improve VIR_ERR_INVALID_DOMAIN usage

In datatype.c, virGetDomainSnapshot could result in the message:

error: invalid domain pointer in bad domain

Furthermore, while there are a few functions in libvirt.c that
only care about a virDomainPtr without regards to the connection
(such as virDomainGetName), most functions also require a valid
connection.  Yet several functions were blindly dereferencing
the conn member without checking it for validity first (such as
virDomainOpenConsole).  Rather than try and correct all usage
of VIR_IS_DOMAIN vs. VIR_IS_CONNECTED_DOMAIN, it is easier to
just blindly require that a valid domain object always has a
valid connection object (which should be true anyways, since
every domain object holds a reference to its connection, so the
connection will not be closed until all domain objects have
also been closed to release their reference).

After this patch, all places that validate a domain consistently
report:

error: invalid domain pointer in someFunc

* src/datatypes.h (virCheckDomainReturn, virCheckDomainGoto): New
macros.
* src/datatypes.c (virGetDomainSnapshot): Use new macro.
(virLibConnError): Delete unused macro.

Signed-off-by: Eric Blake <eblake@redhat.com>

po/POTFILES.in

@@ -32,7 +32,6 @@ src/cpu/cpu_generic.c
 src/cpu/cpu_map.c
 src/cpu/cpu_powerpc.c
 src/cpu/cpu_x86.c
-src/datatypes.c
 src/driver.c
 src/esx/esx_driver.c
 src/esx/esx_network_driver.c

src/datatypes.c

@@ -31,11 +31,6 @@
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
-#define virLibConnError(code, ...)                                \
-    virReportErrorHelper(VIR_FROM_THIS, code, __FILE__,           \
-                         __FUNCTION__, __LINE__, __VA_ARGS__)
-
-
 virClassPtr virConnectClass;
 virClassPtr virConnectCloseCallbackDataClass;
 virClassPtr virDomainClass;
@@ -796,22 +791,19 @@ virGetDomainSnapshot(virDomainPtr domain, const char *name)
     if (virDataTypesInitialize() < 0)
         return NULL;
 
-    if (!VIR_IS_DOMAIN(domain)) {
-        virLibConnError(VIR_ERR_INVALID_DOMAIN, "%s", _("bad domain"));
-        return NULL;
-    }
-    virCheckNonNullArgReturn(name, NULL);
+    virCheckDomainGoto(domain, error);
+    virCheckNonNullArgGoto(name, error);
 
     if (!(ret = virObjectNew(virDomainSnapshotClass)))
-        return NULL;
+        goto error;
     if (VIR_STRDUP(ret->name, name) < 0)
-        goto cleanup;
+        goto error;
 
     ret->domain = virObjectRef(domain);
 
     return ret;
 
-cleanup:
+error:
     virObjectUnref(ret);
     return NULL;
 }

src/datatypes.h

@@ -64,6 +64,29 @@ extern virClassPtr virStoragePoolClass;
     (virObjectIsClass((obj), virDomainClass))
 # define VIR_IS_CONNECTED_DOMAIN(obj) \
     (VIR_IS_DOMAIN(obj) && virObjectIsClass((obj)->conn, virConnectClass))
+# define virCheckDomainReturn(obj, retval)                              \
+    do {                                                                \
+        virDomainPtr _dom = (obj);                                      \
+        if (!virObjectIsClass(_dom, virDomainClass) ||                  \
+            !virObjectIsClass(_dom->conn, virConnectClass)) {           \
+            virReportErrorHelper(VIR_FROM_DOM, VIR_ERR_INVALID_DOMAIN,  \
+                                 __FILE__, __FUNCTION__, __LINE__,      \
+                                 __FUNCTION__);                         \
+            virDispatchError(NULL);                                     \
+            return retval;                                              \
+        }                                                               \
+    } while (0)
+# define virCheckDomainGoto(obj, label)                                 \
+    do {                                                                \
+        virDomainPtr _dom = (obj);                                      \
+        if (!virObjectIsClass(_dom, virDomainClass) ||                  \
+            !virObjectIsClass(_dom->conn, virConnectClass)) {           \
+            virReportErrorHelper(VIR_FROM_DOM, VIR_ERR_INVALID_DOMAIN,  \
+                                 __FILE__, __FUNCTION__, __LINE__,      \
+                                 __FUNCTION__);                         \
+            goto label;                                                 \
+        }                                                               \
+    } while (0)
 
 # define VIR_IS_NETWORK(obj) \
     (virObjectIsClass((obj), virNetworkClass))

src/libvirt-lxc.c

@@ -36,10 +36,6 @@
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
-#define virLibDomainError(domain, error, info)                          \
-    virReportErrorHelper(VIR_FROM_DOM, error, __FILE__, __FUNCTION__,   \
-                         __LINE__, info)
-
 /**
  * virDomainLxcOpenNamespace:
  * @domain: a domain object
@@ -70,12 +66,7 @@ virDomainLxcOpenNamespace(virDomainPtr domain,
 
     virResetLastError();
 
-    if (!VIR_IS_CONNECTED_DOMAIN(domain)) {
-        virLibDomainError(NULL, VIR_ERR_INVALID_DOMAIN, __FUNCTION__);
-        virDispatchError(NULL);
-        return -1;
-    }
-
+    virCheckDomainReturn(domain, -1);
     conn = domain->conn;
 
     virCheckNonNullArgGoto(fdlist, error);

src/libvirt-qemu.c

@@ -30,10 +30,6 @@
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
-#define virLibDomainError(domain, error, info)                          \
-    virReportErrorHelper(VIR_FROM_DOM, error, __FILE__, __FUNCTION__,   \
-                         __LINE__, info)
-
 /**
  * virDomainQemuMonitorCommand:
  * @domain: a domain object
@@ -77,12 +73,7 @@ virDomainQemuMonitorCommand(virDomainPtr domain, const char *cmd,
 
     virResetLastError();
 
-    if (!VIR_IS_CONNECTED_DOMAIN(domain)) {
-        virLibDomainError(NULL, VIR_ERR_INVALID_DOMAIN, __FUNCTION__);
-        virDispatchError(NULL);
-        return -1;
-    }
-
+    virCheckDomainReturn(domain, -1);
     conn = domain->conn;
 
     virCheckNonNullArgGoto(result, error);
@@ -205,12 +196,7 @@ virDomainQemuAgentCommand(virDomainPtr domain,
 
     virResetLastError();
 
-    if (!VIR_IS_CONNECTED_DOMAIN(domain)) {
-        virLibDomainError(NULL, VIR_ERR_INVALID_DOMAIN, __FUNCTION__);
-        virDispatchError(NULL);
-        return NULL;
-    }
-
+    virCheckDomainReturn(domain, NULL);
     conn = domain->conn;
 
     virCheckReadOnlyGoto(conn->flags, error);