Make dirserv_get_routerdescs() return better http 404 error messages instead of a generic "Servers unavailable."

svn:r5274

3 files changed, 31 insertions, 9 deletions

diff --git a/src/or/directory.c b/src/or/directory.c
index b36fa2a58..175ddfbc0 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -1326,14 +1326,16 @@ directory_handle_command_get(connection_t *conn, char *headers,
   if (!strcmpstart(url,"/tor/server/")) {
     size_t url_len = strlen(url);
     int deflated = !strcmp(url+url_len-2, ".z");
+    int res;
+    const char *msg;
     smartlist_t *descs = smartlist_create();
     if (deflated)
       url[url_len-2] = '\0';
-    dirserv_get_routerdescs(descs, url);
+    res = dirserv_get_routerdescs(descs, url, &msg);
     tor_free(url);
-    if (!smartlist_len(descs)) {
-      write_http_status_line(conn, 404, "Servers unavailable");
-    } else {
+    if (res < 0)
+      write_http_status_line(conn, 404, msg);
+    else {
       size_t len = 0;
       format_rfc1123_time(date, time(NULL));
       SMARTLIST_FOREACH(descs, routerinfo_t *, ri,
diff --git a/src/or/dirserv.c b/src/or/dirserv.c
index 3c413e3c2..dab99477a 100644
--- a/src/or/dirserv.c
+++ b/src/or/dirserv.c
@@ -1393,13 +1393,23 @@ dirserv_get_networkstatus_v2(smartlist_t *result,
  *     hex identity digests; or
  *   - "/tor/server/d/D" where D is a plus-separated sequence
  *     of server descriptor digests, in hex.
+ *
+ * Return -1 if we do not have any descriptors, no matching descriptors,
+ *  or if we did not recognize the key (URL), 0 otherwise (i.e. we found some
+ *  matching descriptors).  If -1 is returned <b>msg</b> will be set to
+ *  an appropriate error message.
  */
-void
-dirserv_get_routerdescs(smartlist_t *descs_out, const char *key)
+int
+dirserv_get_routerdescs(smartlist_t *descs_out, const char *key,
+  const char **msg)
 {
   smartlist_t *complete_list = get_descriptor_list();
-  if (!complete_list)
-    return;
+  *msg = NULL;
+
+  if (!complete_list) {
+    *msg = "No server descriptors available";
+    return -1;
+  }
 
   if (!strcmp(key, "/tor/server/all")) {
     smartlist_add_all(descs_out, complete_list);
@@ -1435,7 +1445,16 @@ dirserv_get_routerdescs(smartlist_t *descs_out, const char *key)
        });
     SMARTLIST_FOREACH(digests, char *, d, tor_free(d));
     smartlist_free(digests);
+  } else {
+    *msg = "Key not recognized";
+    return -1;
   }
+
+  if (!smartlist_len(descs_out)) {
+    *msg = "Servers unavailable";
+    return -1;
+  }
+  return 0;
 }
 
 /** Called when a TLS handshake has completed successfully with a
diff --git a/src/or/or.h b/src/or/or.h
index 9e2707e68..45519fc5e 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -1781,7 +1781,8 @@ void dirserv_set_cached_directory(const char *directory, time_t when,
 void dirserv_set_cached_networkstatus_v2(const char *directory, const char *fp,
                                          time_t published);
 int dirserv_get_networkstatus_v2(smartlist_t *result, const char *key);
-void dirserv_get_routerdescs(smartlist_t *descs_out, const char *key);
+int dirserv_get_routerdescs(smartlist_t *descs_out, const char *key,
+                            const char **msg);
 void dirserv_orconn_tls_done(const char *address,
                              uint16_t or_port,
                              const char *digest_rcvd,