30001: Fix a race condition in test_dir_handle_get.c

Previously we used time(NULL) to set the Expires: header in our HTTP
responses.  This made the actual contents of that header untestable,
since the unit tests have no good way to override time(), or to see
what time() was at the exact moment of the call to time() in
dircache.c.

This gave us a race in dir_handle_get/status_vote_next_bandwidth,
where the time() call in dircache.c got one value, and the call in
the tests got another value.

I'm applying our regular solution here: using approx_time() so that
the value stays the same between the code and the test.  Since
approx_time() is updated on every event callback, we shouldn't be
losing any accuracy here.

Fixes bug 30001. Bug introduced in fb4a40c32c4a7e5; not in any
released Tor.

diff --git a/changes/bug30001 b/changes/bug30001
new file mode 100644 (file)
index 0000000..e330470
--- /dev/null
+++ b/changes/bug30001
@@ -0,0 +1,4 @@
+  o Minor features (testing):
+    - Use the approx_time() function when setting the "Expires" header
+      in directory replies, to make them more testable. Needed for
+      ticket 30001.

diff --git a/src/feature/dircache/dircache.c b/src/feature/dircache/dircache.c
index caa085dd6370cef4ca7ac688be35cb7f55af7f8e..1123d034e009afdcdfd1bc269eeb90a08a80358d 100644 (file)
--- a/src/feature/dircache/dircache.c
+++ b/src/feature/dircache/dircache.c
@@ -124,7 +124,7 @@ write_http_response_header_impl(dir_connection_t *conn, ssize_t length,
                            long cache_lifetime)
 {
   char date[RFC1123_TIME_LEN+1];
-  time_t now = time(NULL);
+  time_t now = approx_time();
   buf_t *buf = buf_new_with_capacity(1024);
 
   tor_assert(conn);

diff --git a/src/test/test_dir_handle_get.c b/src/test/test_dir_handle_get.c
index c3a17e730913bd410a3d0b34f5f03d1bada7f56e..e57bd02584b4f100861d57e2608cb80292506da1 100644 (file)
--- a/src/test/test_dir_handle_get.c
+++ b/src/test/test_dir_handle_get.c
@@ -2526,7 +2526,7 @@ test_dir_handle_get_status_vote_next_bandwidth(void* data)
 
   /* Check cache lifetime */
   char expbuf[RFC1123_TIME_LEN+1];
-  time_t now = time(NULL);
+  time_t now = approx_time();
   /* BANDWIDTH_CACHE_LIFETIME is defined in dircache.c. */
   format_rfc1123_time(expbuf, (time_t)(now + 30*60));
   char *expires = NULL;