Do not try to shut down the event loop when it is not initialized.

Doing so caused us to crash in some unusual circumstances, such as
using --verify-config to verify a configuration that failed during
the options_act() stage.

Fixes bug 32407; bugfix on 0.3.3.1-alpha.

2 files changed, 13 insertions, 0 deletions

diff --git a/src/lib/evloop/compat_libevent.c b/src/lib/evloop/compat_libevent.c
index 91eacb9938..939d77f857 100644
--- a/src/lib/evloop/compat_libevent.c
+++ b/src/lib/evloop/compat_libevent.c
@@ -181,6 +181,16 @@ tor_libevent_initialize(tor_libevent_cfg *torcfg)
       event_get_version(), tor_libevent_get_method());
 }
 
+/**
+ * Return true iff the libevent module has been successfully initialized,
+ * and not subsequently shut down.
+ **/
+bool
+tor_libevent_is_initialized(void)
+{
+  return the_event_base != NULL;
+}
+
 /** Return the current Libevent event base that we're set up to use. */
 MOCK_IMPL(struct event_base *,
 tor_libevent_get_base, (void))
diff --git a/src/lib/evloop/compat_libevent.h b/src/lib/evloop/compat_libevent.h
index afe887a013..92724c369c 100644
--- a/src/lib/evloop/compat_libevent.h
+++ b/src/lib/evloop/compat_libevent.h
@@ -13,6 +13,8 @@
 #include "lib/testsupport/testsupport.h"
 #include "lib/malloc/malloc.h"
 
+#include <stdbool.h>
+
 void configure_libevent_logging(void);
 void suppress_libevent_log_msg(const char *msg);
 
@@ -68,6 +70,7 @@ typedef struct tor_libevent_cfg {
 } tor_libevent_cfg;
 
 void tor_libevent_initialize(tor_libevent_cfg *cfg);
+bool tor_libevent_is_initialized(void);
 MOCK_DECL(struct event_base *, tor_libevent_get_base, (void));
 const char *tor_libevent_get_method(void);
 void tor_check_libevent_header_compatibility(void);