Merge pull request #5642 from bosilca/topic/less_mca_mem

Use less memory for the MCA variable names.

opal/mca/base/mca_base_var.c

@@ -1381,7 +1381,7 @@ static int register_variable (const char *project_name, const char *framework_na
         var->mbv_type        = type;
         var->mbv_flags       = flags;
         var->mbv_group_index = group_index;
-        var->mbv_info_lvl  = info_lvl;
+        var->mbv_info_lvl    = info_lvl;
         var->mbv_scope       = scope;
         var->mbv_synonym_for = synonym_for;
         var->mbv_bind        = bind;
@@ -1390,27 +1390,23 @@ static int register_variable (const char *project_name, const char *framework_na
             var->mbv_description = strdup(description);
         }
 
-        if (NULL != variable_name) {
-            var->mbv_variable_name = strdup(variable_name);
-            if (NULL == var->mbv_variable_name) {
-                OBJ_RELEASE(var);
-                return OPAL_ERR_OUT_OF_RESOURCE;
-            }
-        }
-
-        ret = mca_base_var_generate_full_name4 (NULL, framework_name, component_name,
-                                                variable_name, &var->mbv_full_name);
-        if (OPAL_SUCCESS != ret) {
-            OBJ_RELEASE(var);
-            return OPAL_ERROR;
-        }
-
         ret = mca_base_var_generate_full_name4 (project_name, framework_name, component_name,
                                                 variable_name, &var->mbv_long_name);
         if (OPAL_SUCCESS != ret) {
             OBJ_RELEASE(var);
             return OPAL_ERROR;
         }
+        /* The mbv_full_name and the variable name are subset of the mbv_long_name
+         * so instead of allocating them we can just point into the var mbv_long_name
+         * at the right location.
+         */
+        var->mbv_full_name = var->mbv_long_name +
+                             (NULL == project_name ? 0 : (strlen(project_name)+1)); /* 1 for _ */
+        if( NULL != variable_name ) {
+            var->mbv_variable_name = var->mbv_full_name +
+                                     (NULL == framework_name ? 0 : (strlen(framework_name)+1)) +
+                                     (NULL == component_name ? 0 : (strlen(component_name)+1));
+        }
 
         /* Add it to the array.  Note that we copy the mca_var_t by value,
            so the entire contents of the struct is copied.  The synonym list
@@ -1588,31 +1584,27 @@ int mca_base_var_register_synonym (int synonym_for, const char *project_name,
 
 static int var_get_env (mca_base_var_t *var, const char *name, char **source, char **value)
 {
-    char *source_env, *value_env;
+    char envvar[128];
     int ret;
 
-    ret = asprintf (&source_env, "%sSOURCE_%s", mca_prefix, name);
+    ret = snprintf(envvar, 128, "%s%s", mca_prefix, name);
     if (0 > ret) {
+        opal_output(0, "Variable string too short to hold %s%s\n", mca_prefix, name);
         return OPAL_ERROR;
     }
-
-    ret = asprintf (&value_env, "%s%s", mca_prefix, name);
-    if (0 > ret) {
-        free (source_env);
-        return OPAL_ERROR;
-    }
-
-    *source = getenv (source_env);
-    *value = getenv (value_env);
-
-    free (source_env);
-    free (value_env);
-
-    if (NULL == *value) {
+    *value = getenv(envvar);
+    if( NULL == *value ) {
         *source = NULL;
         return OPAL_ERR_NOT_FOUND;
     }
 
+    ret = snprintf(envvar, 128, "%sSOURCE_%s", mca_prefix, name);
+    if( ret >= 128 ) {
+        opal_output(0, "Variable string too short to hold %sSOURCE_%s\n", mca_prefix, name);
+        return OPAL_ERROR;
+    }
+    *source = getenv(envvar);
+
     return OPAL_SUCCESS;
 }
 
@@ -1851,15 +1843,11 @@ static void var_destructor(mca_base_var_t *var)
         OBJ_RELEASE(var->mbv_enumerator);
     }
 
-    if (NULL != var->mbv_variable_name) {
-        free(var->mbv_variable_name);
-    }
-    if (NULL != var->mbv_full_name) {
-        free(var->mbv_full_name);
-    }
     if (NULL != var->mbv_long_name) {
         free(var->mbv_long_name);
     }
+    var->mbv_full_name = NULL;
+    var->mbv_variable_name = NULL;
 
     if (NULL != var->mbv_description) {
         free(var->mbv_description);
@@ -1998,10 +1986,6 @@ static int var_value_string (mca_base_var_t *var, char **value_string)
         } else {
             ret = var->mbv_enumerator->string_from_value(var->mbv_enumerator, value->intval, value_string);
         }
-
-        if (OPAL_SUCCESS != ret) {
-            return ret;
-        }
     }
 
     return ret;