[tor-commits] [tor/master] Add FallbackDir list to GETINFO config/defaults

[nickm at torproject.org]

commit 3bc45f2628b8f9f979835503b42f6ae103dbd703
Author: George Tankersley <george.tankersley at gmail.com>
Date:   Thu Dec 10 22:55:42 2015 -0800

    Add FallbackDir list to GETINFO config/defaults
---
 changes/feature16774   |    3 +++
 src/or/config.c        |   45 +++++++++++++++++++++++++++++++++++++--------
 src/test/test_config.c |    4 +++-
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/changes/feature16774 b/changes/feature16774
new file mode 100644
index 0000000..87ba488
--- /dev/null
+++ b/changes/feature16774
@@ -0,0 +1,3 @@
+  o Minor enhancement:
+    - Adds FallbackDir entries to 'GETINFO config/defaults'. Closes ticket
+      #16774 and 17817. Patch by George Tankersley.
diff --git a/src/or/config.c b/src/or/config.c
index a1f8e49..ff25a79 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -938,6 +938,14 @@ static const char *default_authorities[] = {
   NULL
 };
 
+/** List of fallback directory authorities. The list is generated by opt-in of
+ * relays that meet certain stability criteria.
+ */
+static const char *default_fallbacks[] = {
+#include "fallback_dirs.inc"
+  NULL
+};
+
 /** Add the default directory authorities directly into the trusted dir list,
  * but only add them insofar as they share bits with <b>type</b>.
  * Each authority's bits are restricted to the bits shared with <b>type</b>.
@@ -960,14 +968,10 @@ MOCK_IMPL(void,
 add_default_fallback_dir_servers,(void))
 {
   int i;
-  const char *fallback[] = {
-#include "fallback_dirs.inc"
-    NULL
-  };
-  for (i=0; fallback[i]; i++) {
-    if (parse_dir_fallback_line(fallback[i], 0)<0) {
+  for (i=0; default_fallbacks[i]; i++) {
+    if (parse_dir_fallback_line(default_fallbacks[i], 0)<0) {
       log_err(LD_BUG, "Couldn't parse internal FallbackDir line %s",
-              fallback[i]);
+              default_fallbacks[i]);
     }
   }
 }
@@ -7390,7 +7394,7 @@ getinfo_helper_config(control_connection_t *conn,
     smartlist_free(sl);
   } else if (!strcmp(question, "config/defaults")) {
     smartlist_t *sl = smartlist_new();
-    int i, dirauth_lines_seen = 0;
+    int i, dirauth_lines_seen = 0, fallback_lines_seen = 0;
     for (i = 0; option_vars_[i].name; ++i) {
       const config_var_t *var = &option_vars_[i];
       if (var->initvalue != NULL) {
@@ -7401,6 +7405,13 @@ getinfo_helper_config(control_connection_t *conn,
            */
           ++dirauth_lines_seen;
         }
+        if (strcmp(option_vars_[i].name, "FallbackDir") == 0) {
+          /*
+           * Similarly count fallback lines, so that we can decided later
+           * to add the defaults manually.
+           */
+          ++fallback_lines_seen;
+        }
         char *val = esc_for_log(var->initvalue);
         smartlist_add_asprintf(sl, "%s %s\n",var->name,val);
         tor_free(val);
@@ -7426,6 +7437,24 @@ getinfo_helper_config(control_connection_t *conn,
       }
     }
 
+    if (fallback_lines_seen == 0 &&
+        get_options()->UseDefaultFallbackDirs == 1) {
+      /*
+       * We didn't see any explicitly configured fallback mirrors,
+       * so add the defaults to the list manually.
+       *
+       * default_fallbacks is included earlier in this file and
+       * is a const char ** NULL-terminated array of fallback config lines.
+       */
+      const char **i;
+
+      for (i = default_fallbacks; *i != NULL; ++i) {
+        char *val = esc_for_log(*i);
+        smartlist_add_asprintf(sl, "FallbackDir %s\n", val);
+        tor_free(val);
+      }
+    }
+
     *answer = smartlist_join_strings(sl, "", 0, NULL);
     SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
     smartlist_free(sl);
diff --git a/src/test/test_config.c b/src/test/test_config.c
index 1b9e84d..097fe15 100644
--- a/src/test/test_config.c
+++ b/src/test/test_config.c
@@ -3421,9 +3421,11 @@ test_config_default_dir_servers(void *arg)
   int trusted_count = 0;
   int fallback_count = 0;
 
+  /* new set of options should stop fallback parsing */
   opts = tor_malloc_zero(sizeof(or_options_t));
   opts->UseDefaultFallbackDirs = 0;
-  consider_adding_dir_servers(opts, opts);
+  /* set old_options to NULL to force dir update */
+  consider_adding_dir_servers(opts, NULL);
   trusted_count = smartlist_len(router_get_trusted_dir_servers());
   fallback_count = smartlist_len(router_get_fallback_dir_servers());
   or_options_free(opts);