r14733@catbus: nickm | 2007-08-20 12:32:44 -0400

 Clean up MTBF storage code. Do not count times that we have been down toward the current run.  Handle backward timewarps correctly.  Store MTBF data on exit in addition to periodically.


svn:r11225

1 files changed, 40 insertions, 11 deletions

diff --git a/src/or/rephist.c b/src/or/rephist.c
index a74a28315e..0474ee644a 100644
--- a/src/or/rephist.c
+++ b/src/or/rephist.c
@@ -503,8 +503,19 @@ rep_history_clean(time_t before)
 }
 
 /** DOCDOC */
+static char *
+get_mtbf_filename(void)
+{
+  const char *datadir = get_options()->DataDirectory;
+  size_t len = strlen(datadir)+32;
+  char *fn = tor_malloc(len);
+  tor_snprintf(fn, len, "%s"PATH_SEPARATOR"router-stability", datadir);
+  return fn;
+}
+
+/** DOCDOC */
 int
-rep_hist_record_mtbf_data(const char *filename)
+rep_hist_record_mtbf_data(void)
 {
   char buf[128];
   char time_buf[ISO_TIME_LEN+1];
@@ -529,7 +540,6 @@ rep_hist_record_mtbf_data(const char *filename)
     smartlist_add(lines, tor_strdup(buf));
   }
 
-
   smartlist_add(lines, tor_strdup("data\n"));
 
   for (orhist_it = digestmap_iter_init(history_map);
@@ -557,10 +567,12 @@ rep_hist_record_mtbf_data(const char *filename)
     size_t sz;
     /* XXXX This isn't terribly efficient; line-at-a-time would be
      * way faster. */
+    char *filename = get_mtbf_filename();
     char *data = smartlist_join_strings(lines, "", 0, &sz);
     int r = write_bytes_to_file(filename, data, sz, 0);
 
     tor_free(data);
+    tor_free(filename);
     SMARTLIST_FOREACH(lines, char *, cp, tor_free(cp));
     smartlist_free(lines);
     return r;
@@ -569,16 +581,18 @@ rep_hist_record_mtbf_data(const char *filename)
 
 /** DOCDOC */
 int
-rep_hist_load_mtbf_data(const char *filename, time_t now)
+rep_hist_load_mtbf_data(time_t now)
 {
   /* XXXX won't handle being called while history is already populated. */
   smartlist_t *lines;
   const char *line = NULL;
   int r=0, i;
-  time_t last_downrated = 0;
+  time_t last_downrated = 0, stored_at = 0;
 
   {
+    char *filename = get_mtbf_filename();
     char *d = read_file_to_str(filename, RFTS_IGNORE_MISSING, NULL);
+    tor_free(filename);
     if (!d)
       return -1;
     lines = smartlist_create();
@@ -599,9 +613,20 @@ rep_hist_load_mtbf_data(const char *filename, time_t now)
         log_warn(LD_GENERAL,"Couldn't parse downrate time in mtbf "
                  "history file.");
     }
-    if (last_downrated > now)
-      last_downrated = now;
+    if (!strcmpstart(line, "stored-at ")) {
+      if (parse_iso_time(line+strlen("stored-at "), &stored_at)<0)
+        log_warn(LD_GENERAL,"Couldn't parse stored time in mtbf "
+                 "history file.");
+    }
   }
+  if (last_downrated > now)
+    last_downrated = now;
+
+  if (!stored_at) {
+    log_warn(LD_GENERAL, "No stored time recorded.");
+    goto err;
+  }
+
   if (line && !strcmp(line, "data"))
     ++i;
 
@@ -636,15 +661,19 @@ rep_hist_load_mtbf_data(const char *filename, time_t now)
     hist = get_or_history(digest);
     if (!hist)
       continue;
-    if (start_of_run > now)
-      start_of_run = now;
-    hist->start_of_run = start_of_run;
+
+    if (!start_of_run || start_of_run > stored_at) {
+      hist->start_of_run = 0;
+    } else {
+      long run_length = stored_at - start_of_run;
+      hist->start_of_run = now - run_length;
+    }
+
     hist->weighted_run_length = wrl;
     hist->total_run_weights = trw;
-    /* Subtract time in which */
   }
   if (strcmp(line, "."))
-    log_warn(LD_GENERAL, "Truncated MTBF file %s", escaped(filename));
+    log_warn(LD_GENERAL, "Truncated MTBF file.");
 
   stability_last_downrated = last_downrated;