debugger: fix ofnvram commands for Nubus machines.

debugger/debugger.cpp

@@ -377,7 +377,6 @@ void enter_debugger() {
     size_t separator_pos;
 
     unique_ptr<OfNvramUtils> ofnvram = unique_ptr<OfNvramUtils>(new OfNvramUtils);
-    ofnvram->init();
 
     context = 1; /* start with the PowerPC context */
 
@@ -578,11 +577,15 @@ void enter_debugger() {
             }
 #endif
         } else if (cmd == "printenv") {
+            if (ofnvram->init())
+                continue;
             ofnvram->printenv();
         } else if (cmd == "setenv") {
             string var_name, value;
             ss >> var_name;
             ss >> value;
+            if (ofnvram->init())
+                continue;
             ofnvram->setenv(var_name, value);
         } else {
             cout << "Unknown command: " << cmd << endl;

devices/common/ofnvram.cpp

@@ -37,9 +37,10 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 using namespace std;
 
-void OfNvramUtils::init()
+int OfNvramUtils::init()
 {
     this->nvram_obj = dynamic_cast<NVram*>(gMachineObj->get_comp_by_name("NVRAM"));
+    return this->nvram_obj == nullptr;
 }
 
 bool OfNvramUtils::validate()

devices/common/ofnvram.h

@@ -49,7 +49,7 @@ public:
     OfNvramUtils()  = default;
     ~OfNvramUtils() = default;
 
-    void init();
+    int  init();
     void printenv();
     void setenv(std::string var_name, std::string value);