Add: GETINFO support for dumping microdesc consensus

test: case to check GETINFO consensus commands are functional.
fix: code structure
update: changes with human readable description
fix: command naming convention
add: test case checks if consensus body is returned
fix: potential memory leak

changes/ticket31684

@@ -1,2 +1,2 @@
   o Minor features (onion services):
-    - GETINFO dir/status-vote/current/consensus-microdesc dumps microdesc consensus. Closes ticket 31684.
+    - Implement a new GETINFO command to fetch consensus. Closes ticket 31684.

src/feature/control/control_getinfo.c

@@ -326,46 +326,36 @@ getinfo_helper_current_time(control_connection_t *control_conn,
 }
 
 /**
- * Switch between microdesc vs networkstatus descriptor dumps
- * Assumes that question would be either:
- * - dir/status-vote/current/consensus-microdesc
- * or
- * - dir/status-vote/current/consensus
+ * Helps to access directory information for a given
+ * type of consensus.
+ *
+ * returns: int
+ *   -1 in cases of an error
+ *   0 otherwise
  */
 STATIC int
-getinfo_helper_current_consensus(const char* question,
-                          char** answer,
-                          const char** errmsg)
+getinfo_helper_current_consensus(const char* consensus_type,
+                                 int flavor, char** answer,
+                                 const char** errmsg)
 {
-  // Ensures question contains a request for
-  // ns or microdesc consensus
-  if (
-      strcmp(question, "dir/status-vote/current/consensus") &&
-      strcmp(question, "dir/status-vote/current/consensus-microdesc")) {
-    return 0;
-  }
-
-  const char* consensus_type = !strcmp(
-     question, "dir/status-vote/current/consensus-microdesc"
-  ) ? "microdesc" : "ns";
-
-  if (we_want_to_fetch_flavor(get_options(), FLAV_NS)) {
+  /** Check if the consensus flavor is cached or in the ram. */
+  if (we_want_to_fetch_flavor(get_options(), flavor)) {
     const cached_dir_t *consensus = dirserv_get_consensus(consensus_type);
     if (consensus) {
       *answer = tor_strdup(consensus->dir);
     }
   }
-  if (!*answer) { /* try loading it from disk */
+  if (!*answer) { /* else, try loading consensus from disk */
     tor_mmap_t *mapped = networkstatus_map_cached_consensus(consensus_type);
     if (mapped) {
       *answer = tor_memdup_nulterm(mapped->data, mapped->size);
       tor_munmap_file(mapped);
     }
-    if (!*answer) { /* generate an error */
-      *errmsg = "Could not open cached consensus. "
-        "Make sure FetchUselessDescriptors is set to 1.";
-       return -1;
-   }
+  }
+  if (!*answer) { /* generate an error */
+    *errmsg = "Could not open cached consensus. "
+      "Make sure FetchUselessDescriptors is set to 1.";
+    return -1;
   }
   return 0;
 }
@@ -622,16 +612,17 @@ getinfo_helper_dir(control_connection_t *control_conn,
     smartlist_free(descs);
   } else if (!strcmpstart(question, "dir/status/")) {
     *answer = tor_strdup("");
-  } else if (-1 == getinfo_helper_current_consensus(
-                                                    question,
-                                                    answer,
-                                                    errmsg))
-  {
-    /**
-     * answer is set by getinfo_helper_current_consensus
-     * if the question matches
-     */
-    return -1;
+  } else if (!strcmp(question, "dir/status-vote/current/consensus")) {
+    if (getinfo_helper_current_consensus(
+         "ns", FLAV_NS, answer, errmsg) == -1) {
+      return -1;
+    }
+  } else if (!strcmp(question, "dir/status-vote/current/consensus-microdesc"))
+    {
+      if (getinfo_helper_current_consensus(
+           "microdesc", FLAV_MICRODESC, answer, errmsg) == -1) {
+        return -1;
+      }
   } else if (!strcmp(question, "network-status")) { /* v1 */
     static int network_status_warned = 0;
     if (!network_status_warned) {

src/feature/control/control_getinfo.h

@@ -49,7 +49,8 @@ STATIC int getinfo_helper_downloads(
     const char *question, char **answer,
     const char **errmsg);
 STATIC int getinfo_helper_current_consensus(
-    const char *question, char **answer,
+    const char *question, int flavor,
+    char **answer,
     const char **errmsg);
 STATIC int getinfo_helper_dir(
     control_connection_t *control_conn,

src/feature/nodelist/networkstatus.c

@@ -241,10 +241,9 @@ networkstatus_get_cache_fname(int flav,
  * Read and and return the cached consensus of type <b>flavorname</b>.  If
  * <b>unverified</b> is false, get the one we haven't verified. Return NULL if
  * the file isn't there. */
-static tor_mmap_t *
-networkstatus_map_cached_consensus_impl(int flav,
-                                        const char *flavorname,
-                                        int unverified_consensus)
+MOCK_IMPL(tor_mmap_t *,
+          networkstatus_map_cached_consensus_impl,
+          (int flav, const char *flavorname, int unverified_consensus))
 {
   char *filename = networkstatus_get_cache_fname(flav,
                                                  flavorname,
@@ -256,8 +255,9 @@ networkstatus_map_cached_consensus_impl(int flav,
 
 /** Map the file containing the current cached consensus of flavor
  * <b>flavorname</b> */
-tor_mmap_t *
-networkstatus_map_cached_consensus(const char *flavorname)
+MOCK_IMPL(tor_mmap_t *,
+          networkstatus_map_cached_consensus,
+          (const char *flavorname))
 {
   int flav = networkstatus_parse_flavor_name(flavorname);
   if (flav < 0)

src/feature/nodelist/networkstatus.h

@@ -16,7 +16,14 @@
 
 void networkstatus_reset_warnings(void);
 void networkstatus_reset_download_failures(void);
-tor_mmap_t *networkstatus_map_cached_consensus(const char *flavorname);
+
+MOCK_DECL(tor_mmap_t *,
+          networkstatus_map_cached_consensus_impl,
+          (int flav, const char *flavorname, int unverified_consensus));
+
+MOCK_DECL(tor_mmap_t *,
+          networkstatus_map_cached_consensus,
+          (const char *flavorname));
 int router_reload_consensus_networkstatus(void);
 void routerstatus_free_(routerstatus_t *rs);
 #define routerstatus_free(rs) \

src/test/test_controller.c

@@ -756,6 +756,12 @@ static download_status_t descbr_digest_2_dl;
 static const char *descbr_expected_list =
     "616408544C7345822696074A1A3DFA16AB381CBD\n"
     "06E8067246967265DBCB6641631B530EFEC12DC3\n";
+
+/** Simulated Networkstatus consensus */
+static const char *mock_ns_consensus = "mock_ns_consensus";
+/** Simulated Microdesc consensus */
+static const char *mock_microdesc_consensus = "mock_microdesc_consensus";
+
 /*
  * Flag to make all descbr queries fail, to simulate not being
  * configured such that such queries make sense.
@@ -1689,6 +1695,72 @@ test_download_status_bridge(void *arg)
   return;
 }
 
+tor_mmap_t *
+mock_networkstatus_map_cached_consensus_impl(int flav,
+                                        const char *flavorname,
+                                        int unverified_consensus);
+
+tor_mmap_t *
+mock_networkstatus_map_cached_consensus_impl(int flav,
+                                        const char *flavorname,
+                                        int unverified_consensus)
+{
+  tor_mmap_t *res = tor_malloc_zero(sizeof(tor_mmap_t));
+
+  /** Suppress error on the CI */
+  flav = flav;
+  unverified_consensus = unverified_consensus;
+
+  if (!strcmp(flavorname, "ns")) {
+    res->data = "mock_ns_consensus";
+  }
+  if (!strcmp(flavorname, "microdesc")) {
+    res->data = "mock_microdesc_consensus";
+  }
+  res->size = strlen(res->data);
+  return res;
+}
+
+static void
+test_getinfo_helper_dir(void *arg)
+{
+  /* We just need one of these to pass, it doesn't matter what's in it */
+  control_connection_t dummy;
+  /* Get results out */
+  char *answer = NULL;
+  const char *errmsg = NULL;
+
+  (void)arg;
+
+  setup_bridge_mocks();
+  MOCK(networkstatus_map_cached_consensus_impl,
+       mock_networkstatus_map_cached_consensus_impl);
+
+  getinfo_helper_dir(&dummy,
+                     "dir/status-vote/current/consensus",
+                     &answer,
+                     &errmsg);
+  tt_str_op(answer, OP_EQ, mock_ns_consensus);
+  tt_ptr_op(errmsg, OP_EQ, NULL);
+  tor_free(answer);
+  answer = NULL;
+  errmsg = NULL;
+
+  getinfo_helper_dir(&dummy,
+                     "dir/status-vote/current/consensus-microdesc",
+                     &answer,
+                     &errmsg);
+  tt_str_op(answer, OP_EQ, mock_microdesc_consensus);
+  tt_ptr_op(errmsg, OP_EQ, NULL);
+  tor_free(answer);
+
+ done:
+  clear_bridge_mocks();
+  tor_free(answer);
+  UNMOCK(networkstatus_map_cached_consensus_impl);
+  return;
+}
+
 /** Set timeval to a mock date and time. This is necessary
  * to make tor_gettimeofday() mockable. */
 static void
@@ -1740,7 +1812,6 @@ test_current_time(void *arg)
  done:
   UNMOCK(tor_gettimeofday);
   tor_free(answer);
-
   return;
 }
 
@@ -1838,6 +1909,8 @@ struct testcase_t controller_tests[] = {
     NULL },
   { "download_status_consensus", test_download_status_consensus, 0, NULL,
     NULL },
+  {"getinfo_helper_current_consensus", test_getinfo_helper_dir, 0, NULL,
+   NULL },
   { "download_status_cert", test_download_status_cert, 0, NULL,
     NULL },
   { "download_status_desc", test_download_status_desc, 0, NULL, NULL },