Merge remote-tracking branch 'public/bug8822' into maint-0.2.4

changes/bug8822

@@ -0,0 +1,5 @@
+  o Major bugfixes (windows):
+    - Prevent failures on Windows Vista and later when rebuilding the
+      microdescriptor cache. Diagnosed by Robert Ransom. Fixes bug 8822;
+      bugfix on 0.2.4.12-alpha.
+

src/or/control.c

@@ -1711,8 +1711,7 @@ getinfo_helper_dir(control_connection_t *control_conn,
     const node_t *node = node_get_by_hex_id(question+strlen("md/id/"));
     const microdesc_t *md = NULL;
     if (node) md = node->md;
-    if (md) {
-      tor_assert(md->body);
+    if (md && md->body) {
       *answer = tor_strndup(md->body, md->bodylen);
     }
   } else if (!strcmpstart(question, "md/name/")) {
@@ -1722,8 +1721,7 @@ getinfo_helper_dir(control_connection_t *control_conn,
     /* XXXX duplicated code */
     const microdesc_t *md = NULL;
     if (node) md = node->md;
-    if (md) {
-      tor_assert(md->body);
+    if (md && md->body) {
       *answer = tor_strndup(md->body, md->bodylen);
     }
   } else if (!strcmpstart(question, "desc-annotations/id/")) {

src/or/dirserv.c

@@ -3981,7 +3981,7 @@ connection_dirserv_add_microdescs_to_outbuf(dir_connection_t *conn)
     char *fp256 = smartlist_pop_last(conn->fingerprint_stack);
     microdesc_t *md = microdesc_cache_lookup_by_digest256(cache, fp256);
     tor_free(fp256);
-    if (!md)
+    if (!md || !md->body)
       continue;
     if (conn->zlib_state) {
       /* XXXX024 This 'last' business should actually happen on the last

src/or/microdesc.c

@@ -75,6 +75,10 @@ dump_microdescriptor(int fd, microdesc_t *md, size_t *annotation_len_out)
 {
   ssize_t r = 0;
   size_t written;
+  if (md->body == NULL) {
+    *annotation_len_out = 0;
+    return 0;
+  }
   /* XXXX drops unknown annotations. */
   if (md->last_listed) {
     char buf[ISO_TIME_LEN+1];
@@ -447,7 +451,7 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
   HT_FOREACH(mdp, microdesc_map, &cache->map) {
     microdesc_t *md = *mdp;
     size_t annotation_len;
-    if (md->no_save)
+    if (md->no_save || !md->body)
       continue;
 
     size = dump_microdescriptor(fd, md, &annotation_len);
@@ -474,15 +478,29 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
     smartlist_add(wrote, md);
   }
 
+  /* We must do this unmap _before_ we call finish_writing_to_file(), or
+   * windows will not actually replace the file. */
+  if (cache->cache_content)
+    tor_munmap_file(cache->cache_content);
+
   if (finish_writing_to_file(open_file) < 0) {
     log_warn(LD_DIR, "Error rebuilding microdescriptor cache: %s",
              strerror(errno));
+    /* Okay. Let's prevent from making things worse elsewhere. */
+    cache->cache_content = NULL;
+    HT_FOREACH(mdp, microdesc_map, &cache->map) {
+      microdesc_t *md = *mdp;
+      if (md->saved_location == SAVED_IN_CACHE) {
+        md->off = 0;
+        md->saved_location = SAVED_NOWHERE;
+        md->body = NULL;
+        md->bodylen = 0;
+        md->no_save = 1;
+      }
+    }
     return -1;
   }
 
-  if (cache->cache_content)
-    tor_munmap_file(cache->cache_content);
-
   cache->cache_content = tor_mmap_file(cache->cache_fname);
 
   if (!cache->cache_content && smartlist_len(wrote)) {