resolve lucky's recent bug: tor was exiting if we failed to spawn

a new dns worker (e.g. because we were out of fd's).


svn:r5112

src/or/dns.c

@@ -73,7 +73,7 @@ static void dns_purge_resolve(cached_resolve_t *resolve);
 static void dns_found_answer(char *address, uint32_t addr, char outcome);
 static int dnsworker_main(void *data);
 static int spawn_dnsworker(void);
-static void spawn_enough_dnsworkers(void);
+static int spawn_enough_dnsworkers(void);
 static void send_resolved_cell(connection_t *conn, uint8_t answer_type);
 
 /** Splay tree of cached_resolve objects. */
@@ -334,7 +334,10 @@ assign_to_dnsworker(connection_t *exitconn)
   tor_assert(exitconn->state == EXIT_CONN_STATE_RESOLVING);
   tor_assert(exitconn->s == -1);
 
-  spawn_enough_dnsworkers(); /* respawn here, to be sure there are enough */
+  /* respawn here, to be sure there are enough */
+  if (spawn_enough_dnsworkers() < 0) {
+    goto err;
+  }
 
   dnsconn = connection_get_by_type_state(CONN_TYPE_DNSWORKER, DNSWORKER_STATE_IDLE);
 
@@ -342,8 +345,7 @@ assign_to_dnsworker(connection_t *exitconn)
     log_fn(LOG_WARN,"no idle dns workers. Failing.");
     if (exitconn->purpose == EXIT_PURPOSE_RESOLVE)
       send_resolved_cell(exitconn, RESOLVED_TYPE_ERROR_TRANSIENT);
-    dns_cancel_pending_resolve(exitconn->address); /* also sends end and frees! */
-    return -1;
+    goto err;
   }
 
   log_fn(LOG_DEBUG, "Connection (fd %d) needs to resolve '%s'; assigning to DNSWorker (fd %d)",
@@ -359,6 +361,9 @@ assign_to_dnsworker(connection_t *exitconn)
   connection_write_to_buf(dnsconn->address, len, dnsconn);
 
   return 0;
+err:
+  dns_cancel_pending_resolve(exitconn->address); /* also sends end and frees! */
+  return -1;
 }
 
 /** Remove <b>conn</b> from the list of connections waiting for conn-\>address.
@@ -834,10 +839,9 @@ spawn_dnsworker(void)
 
   fdarray = tor_malloc(sizeof(int)*2);
   if ((err = tor_socketpair(AF_UNIX, SOCK_STREAM, 0, fdarray)) < 0) {
-    log(LOG_ERR, "Couldn't construct socketpair: %s", tor_socket_strerror(-err));
-    tor_cleanup();
+    log(LOG_WARN, "Couldn't construct socketpair: %s", tor_socket_strerror(-err));
     tor_free(fdarray);
-    exit(1);
+    return -1;
   }
 
   /* log_fn(LOG_NOTICE,"Before spawn: fdarray @%d has %d:%d", (int)fdarray, fdarray[0],fdarray[1]); */
@@ -871,8 +875,10 @@ spawn_dnsworker(void)
 }
 
 /** If we have too many or too few DNS workers, spawn or kill some.
+ * Return 0 if we are happy, return -1 if we tried to spawn more but
+ * we couldn't.
  */
-static void
+static int
 spawn_enough_dnsworkers(void)
 {
   int num_dnsworkers_needed; /* aim to have 1 more than needed,
@@ -911,7 +917,7 @@ spawn_enough_dnsworkers(void)
   while (num_dnsworkers < num_dnsworkers_needed) {
     if (spawn_dnsworker() < 0) {
       log_fn(LOG_WARN,"spawn failed!");
-      return;
+      return -1;
     }
     num_dnsworkers++;
   }
@@ -926,5 +932,7 @@ spawn_enough_dnsworkers(void)
     connection_mark_for_close(dnsconn);
     num_dnsworkers--;
   }
+
+  return 0;
 }