Update Tor to use Libevent 2.0 APIs when available.

This patch adds a new compat_libevent.[ch] set of files, and moves our
Libevent compatibility and utilitity functions there.  We build them
into a separate .a so that nothing else in src/commmon depends on
Libevent (partially fixing bug 507).

Also, do not use our own built-in evdns copy when we have Libevent
2.0, whose evdns is finally good enough (thus fixing Bug 920).

.gitignore

@@ -111,6 +111,7 @@
 /src/common/common_sha1.i
 /src/common/libor.a
 /src/common/libor-crypto.a
+/src/common/libor-event.a
 
 # /src/config/
 /src/config/Makefile

configure.in

@@ -273,15 +273,19 @@ save_CPPFLAGS="$CPPFLAGS"
 LIBS="-levent $TOR_LIB_WS32 $LIBS"
 LDFLAGS="$TOR_LDFLAGS_libevent $LDFLAGS"
 CPPFLAGS="$TOR_CPPFLAGS_libevent $CPPFLAGS"
-AC_CHECK_FUNCS(event_get_version event_get_method event_set_log_callback)
+AC_CHECK_FUNCS(event_get_version event_get_method event_set_log_callback evdns_set_outgoing_bind_address)
 AC_CHECK_MEMBERS([struct event.min_heap_idx], , ,
 [#include <event.h>
 ])
 
+AC_CHECK_HEADERS(event2/event.h event2/dns.h)
+
 LIBS="$save_LIBS"
 LDFLAGS="$save_LDFLAGS"
 CPPFLAGS="$save_CPPFLAGS"
 
+AM_CONDITIONAL(USE_EXTERNAL_EVDNS, test x$ac_cv_header_event2_dns_h = xyes)
+
 dnl ------------------------------------------------------
 dnl Where do you live, openssl?  And how do we call you?
 

src/common/Makefile.am

@@ -1,5 +1,5 @@
 
-noinst_LIBRARIES = libor.a libor-crypto.a
+noinst_LIBRARIES = libor.a libor-crypto.a libor-event.a
 
 EXTRA_DIST = common_sha1.i
 
@@ -14,8 +14,9 @@ endif
 libor_a_SOURCES = address.c log.c util.c compat.c container.c mempool.c \
 	memarea.c util_codedigest.c $(libor_extra_source)
 libor_crypto_a_SOURCES = crypto.c aes.c tortls.c torgzip.c
+libor_event_a_SOURCES = compat_libevent.c
 
-noinst_HEADERS = address.h log.h crypto.h test.h util.h compat.h aes.h torint.h tortls.h strlcpy.c strlcat.c torgzip.h container.h ht.h mempool.h memarea.h ciphers.inc
+noinst_HEADERS = address.h log.h crypto.h test.h util.h compat.h aes.h torint.h tortls.h strlcpy.c strlcat.c torgzip.h container.h ht.h mempool.h memarea.h ciphers.inc compat_libevent.h
 
 common_sha1.i: $(libor_SOURCES) $(libor_crypto_a_SOURCES) $(noinst_HEADERS)
 	if test "@SHA1SUM@" != none; then \

src/common/compat_libevent.c

@@ -0,0 +1,153 @@
+/* Copyright (c) 2009, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file compat_libevent.c
+ * \brief Wrappers to handle porting between different versions of libevent.
+ *
+ * In an ideal world, we'd just use Libevent 2.0 from now on.  But as of June
+ * 2009, Libevent 2.0 is still in alpha, and we will have old versions of
+ * Libevent for the forseeable future.
+ **/
+
+#include "orconfig.h"
+#include "compat_libevent.h"
+
+#include "compat.h"
+#include "util.h"
+#include "log.h"
+
+#ifdef HAVE_EVENT2_EVENT_H
+#include <event2/event.h>
+#else
+#include <event.h>
+#endif
+
+#ifdef HAVE_EVENT_SET_LOG_CALLBACK
+/** A string which, if it appears in a libevent log, should be ignored. */
+static const char *suppress_msg = NULL;
+/** Callback function passed to event_set_log() so we can intercept
+ * log messages from libevent. */
+static void
+libevent_logging_callback(int severity, const char *msg)
+{
+  char buf[1024];
+  size_t n;
+  if (suppress_msg && strstr(msg, suppress_msg))
+    return;
+  n = strlcpy(buf, msg, sizeof(buf));
+  if (n && n < sizeof(buf) && buf[n-1] == '\n') {
+    buf[n-1] = '\0';
+  }
+  switch (severity) {
+    case _EVENT_LOG_DEBUG:
+      log(LOG_DEBUG, LD_NET, "Message from libevent: %s", buf);
+      break;
+    case _EVENT_LOG_MSG:
+      log(LOG_INFO, LD_NET, "Message from libevent: %s", buf);
+      break;
+    case _EVENT_LOG_WARN:
+      log(LOG_WARN, LD_GENERAL, "Warning from libevent: %s", buf);
+      break;
+    case _EVENT_LOG_ERR:
+      log(LOG_ERR, LD_GENERAL, "Error from libevent: %s", buf);
+      break;
+    default:
+      log(LOG_WARN, LD_GENERAL, "Message [%d] from libevent: %s",
+          severity, buf);
+      break;
+  }
+}
+/** Set hook to intercept log messages from libevent. */
+void
+configure_libevent_logging(void)
+{
+  event_set_log_callback(libevent_logging_callback);
+}
+/** Ignore any libevent log message that contains <b>msg</b>. */
+void
+suppress_libevent_log_msg(const char *msg)
+{
+  suppress_msg = msg;
+}
+#else
+void
+configure_libevent_logging(void)
+{
+}
+void
+suppress_libevent_log_msg(const char *msg)
+{
+  (void)msg;
+}
+#endif
+
+#ifndef HAVE_EVENT2_EVENT_H
+/** Work-alike replacement for event_new() on pre-Libevent-2.0 systems. */
+struct event *
+tor_event_new(struct event_base *base, int sock, short what,
+              void (*cb)(int, short, void *), void *arg)
+{
+  struct event *e = tor_malloc_zero(sizeof(struct event));
+  event_set(e, sock, what, cb, arg);
+  event_base_set(base, e);
+  return e;
+}
+/** Work-alike replacement for evtimer_new() on pre-Libevent-2.0 systems. */
+struct event *
+tor_evtimer_new(struct event_base *base,
+                void (*cb)(int, short, void *), void *arg)
+{
+  return tor_event_new(base, -1, 0, cb, arg);
+}
+/** Work-alike replacement for evsignal_new() on pre-Libevent-2.0 systems. */
+struct event *
+tor_evsignal_new(struct event_base * base, int sig,
+                 void (*cb)(int, short, void *), void *arg)
+{
+  return tor_event_new(base, sig, EV_SIGNAL, cb, arg);
+}
+/** Work-alike replacement for event_free() on pre-Libevent-2.0 systems. */
+void
+tor_event_free(struct event *ev)
+{
+  event_del(ev);
+  tor_free(ev);
+}
+#endif
+
+/** Global event base for use by the main thread. */
+struct event_base *the_event_base = NULL;
+
+/** Initialize the Libevent library and set up the event base. */
+void
+tor_libevent_initialize(void)
+{
+  tor_assert(the_event_base == NULL);
+#ifdef HAVE_EVENT2_EVENT_H
+  the_event_base = event_base_new();
+#else
+  the_event_base = event_init();
+#endif
+}
+
+/** Return the current Libevent event base that we're set up to use. */
+struct event_base *
+tor_libevent_get_base(void)
+{
+  return the_event_base;
+}
+
+/** Return the name of the Libevent backend we're using. */
+const char *
+tor_libevent_get_method(void)
+{
+#ifdef HAVE_EVENT2_EVENT_H
+  return event_base_get_method(the_event_base);
+#elif defined(HAVE_EVENT_GET_METHOD)
+  return event_get_method();
+#else
+  return "<unknown>";
+#endif
+}
+

src/common/compat_libevent.h

@@ -0,0 +1,39 @@
+/* Copyright (c) 2009, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef _TOR_COMPAT_LIBEVENT_H
+#define _TOR_COMPAT_LIBEVENT_H
+
+#include "orconfig.h"
+
+#ifdef HAVE_EVENT2_EVENT_H
+#include <event2/event.h>
+#else
+#include <event.h>
+#define evutil_socket_t int
+#endif
+
+void configure_libevent_logging(void);
+void suppress_libevent_log_msg(const char *msg);
+
+#ifdef HAVE_EVENT2_EVENT_H
+#define tor_event_new     event_new
+#define tor_evtimer_new   evtimer_new
+#define tor_evsignal_new  evsignal_new
+#define tor_event_free    event_free
+#else
+struct event *tor_event_new(struct event_base * base, evutil_socket_t sock,
+           short what, void (*cb)(evutil_socket_t, short, void *), void *arg);
+struct event *tor_evtimer_new(struct event_base * base,
+            void (*cb)(evutil_socket_t, short, void *), void *arg);
+struct event *tor_evsignal_new(struct event_base * base, int sig,
+            void (*cb)(evutil_socket_t, short, void *), void *arg);
+void tor_event_free(struct event *ev);
+#endif
+
+void tor_libevent_initialize(void);
+struct event_base *tor_libevent_get_base(void);
+const char *tor_libevent_get_method(void);
+
+#endif
+

src/common/log.c

@@ -36,8 +36,6 @@
 #include "log.h"
 #include "container.h"
 
-#include <event.h>
-
 #define TRUNCATED_STR "[...truncated]"
 #define TRUNCATED_STR_LEN 14
 
@@ -921,65 +919,6 @@ switch_logs_debug(void)
   UNLOCK_LOGS();
 }
 
-#ifdef HAVE_EVENT_SET_LOG_CALLBACK
-/** A string which, if it appears in a libevent log, should be ignored. */
-static const char *suppress_msg = NULL;
-/** Callback function passed to event_set_log() so we can intercept
- * log messages from libevent. */
-static void
-libevent_logging_callback(int severity, const char *msg)
-{
-  char buf[1024];
-  size_t n;
-  if (suppress_msg && strstr(msg, suppress_msg))
-    return;
-  n = strlcpy(buf, msg, sizeof(buf));
-  if (n && n < sizeof(buf) && buf[n-1] == '\n') {
-    buf[n-1] = '\0';
-  }
-  switch (severity) {
-    case _EVENT_LOG_DEBUG:
-      log(LOG_DEBUG, LD_NET, "Message from libevent: %s", buf);
-      break;
-    case _EVENT_LOG_MSG:
-      log(LOG_INFO, LD_NET, "Message from libevent: %s", buf);
-      break;
-    case _EVENT_LOG_WARN:
-      log(LOG_WARN, LD_GENERAL, "Warning from libevent: %s", buf);
-      break;
-    case _EVENT_LOG_ERR:
-      log(LOG_ERR, LD_GENERAL, "Error from libevent: %s", buf);
-      break;
-    default:
-      log(LOG_WARN, LD_GENERAL, "Message [%d] from libevent: %s",
-          severity, buf);
-      break;
-  }
-}
-/** Set hook to intercept log messages from libevent. */
-void
-configure_libevent_logging(void)
-{
-  event_set_log_callback(libevent_logging_callback);
-}
-/** Ignore any libevent log message that contains <b>msg</b>. */
-void
-suppress_libevent_log_msg(const char *msg)
-{
-  suppress_msg = msg;
-}
-#else
-void
-configure_libevent_logging(void)
-{
-}
-void
-suppress_libevent_log_msg(const char *msg)
-{
-  (void)msg;
-}
-#endif
-
 #if 0
 static void
 dump_log_info(logfile_t *lf)

src/common/log.h

@@ -134,8 +134,6 @@ void add_temp_log(int min_severity);
 void close_temp_logs(void);
 void rollback_log_changes(void);
 void mark_logs_temp(void);
-void configure_libevent_logging(void);
-void suppress_libevent_log_msg(const char *msg);
 void change_callback_log_severity(int loglevelMin, int loglevelMax,
                                   log_callback cb);
 void log_set_application_name(const char *name);

src/or/Makefile.am

@@ -12,7 +12,13 @@ endif
 
 EXTRA_DIST=ntmain.c or_sha1.i
 
-tor_SOURCES = buffers.c circuitbuild.c circuitlist.c \
+if USE_EXTERNAL_EVDNS
+evdns_source=
+else
+evdns_source=eventdns.c
+endif
+
+COMMON_SRC = buffers.c circuitbuild.c circuitlist.c \
 	circuituse.c command.c config.c \
 	connection.c connection_edge.c connection_or.c control.c \
 	cpuworker.c directory.c dirserv.c dirvote.c \
@@ -20,8 +26,9 @@ tor_SOURCES = buffers.c circuitbuild.c circuitlist.c \
 	networkstatus.c onion.c policies.c \
 	reasons.c relay.c rendcommon.c rendclient.c rendmid.c \
 	rendservice.c rephist.c router.c routerlist.c routerparse.c \
-	eventdns.c config_codedigest.c \
-	tor_main.c
+	$(evdns_source) config_codedigest.c
+
+tor_SOURCES = $(COMMON_SRC) tor_main.c
 
 AM_CPPFLAGS = -DSHARE_DATADIR="\"$(datadir)\"" \
         -DLOCALSTATEDIR="\"$(localstatedir)\"" \
@@ -33,22 +40,15 @@ AM_CPPFLAGS = -DSHARE_DATADIR="\"$(datadir)\"" \
 
 tor_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ @TOR_LDFLAGS_libevent@
 tor_LDADD = ../common/libor.a ../common/libor-crypto.a \
-  -lz -levent -lssl -lcrypto @TOR_LIB_WS32@ @TOR_LIB_GDI@
-test_SOURCES = buffers.c circuitbuild.c circuitlist.c \
-	circuituse.c command.c config.c \
-	connection.c connection_edge.c connection_or.c control.c \
-	cpuworker.c directory.c dirserv.c dirvote.c \
-	dns.c dnsserv.c geoip.c hibernate.c main.c $(tor_platform_source) \
-	networkstatus.c onion.c policies.c \
-	reasons.c relay.c rendcommon.c rendclient.c rendmid.c \
-	rendservice.c rephist.c router.c routerlist.c routerparse.c \
-	eventdns.c config_codedigest.c \
-	test_data.c test.c
+	../common/libor-event.a \
+	-lz -levent -lssl -lcrypto @TOR_LIB_WS32@ @TOR_LIB_GDI@
+test_SOURCES = $(COMMON_SRC) test_data.c test.c
 
 test_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
         @TOR_LDFLAGS_libevent@
 test_LDADD = ../common/libor.a ../common/libor-crypto.a \
-        -lz -levent -lssl -lcrypto @TOR_LIB_WS32@ @TOR_LIB_GDI@
+	../common/libor-event.a \
+	-lz -levent -lssl -lcrypto @TOR_LIB_WS32@ @TOR_LIB_GDI@
 
 noinst_HEADERS = or.h eventdns.h eventdns_tor.h micro-revision.i
 

src/or/config.c

@@ -4903,15 +4903,17 @@ init_libevent(void)
   /* Your libevent is ancient. */
 #endif
 
-  event_init();
+  tor_libevent_initialize();
+
   suppress_libevent_log_msg(NULL);
 #if defined(HAVE_EVENT_GET_VERSION) && defined(HAVE_EVENT_GET_METHOD)
   /* Making this a NOTICE for now so we can link bugs to a libevent versions
    * or methods better. */
   log(LOG_NOTICE, LD_GENERAL,
       "Initialized libevent version %s using method %s. Good.",
-      event_get_version(), event_get_method());
-  check_libevent_version(event_get_method(), get_options()->ORPort != 0);
+      event_get_version(), tor_libevent_get_method());
+  check_libevent_version(tor_libevent_get_method(),
+                         get_options()->ORPort != 0);
 #else
   log(LOG_NOTICE, LD_GENERAL,
       "Initialized old libevent (version 1.0b or earlier).");

src/or/dns.c

@@ -13,7 +13,15 @@
 
 #include "or.h"
 #include "ht.h"
+#ifdef HAVE_EVENT2_DNS_H
+#include <event2/dns.h>
+#include <event2/dns_compat.h>
+#else
 #include "eventdns.h"
+#ifndef HAVE_EVDNS_SET_DEFAULT_OUTGOING_BIND_ADDRESS
+#define HAVE_EVDNS_SET_DEFAULT_OUTGOING_BIND_ADDRESS
+#endif
+#endif
 
 /** Longest hostname we're willing to resolve. */
 #define MAX_ADDRESSLEN 256
@@ -1108,6 +1116,7 @@ configure_nameservers(int force)
     conf_fname = "/etc/resolv.conf";
 #endif
 
+#ifdef HAVE_EVDNS_SET_DEFAULT_OUTGOING_BIND_ADDRESS
   if (options->OutboundBindAddress) {
     tor_addr_t addr;
     if (tor_addr_from_str(&addr, options->OutboundBindAddress) < 0) {
@@ -1127,6 +1136,7 @@ configure_nameservers(int force)
       }
     }
   }
+#endif
 
   if (options->ServerDNSRandomizeCase)
     evdns_set_option("randomize-case:", "1", DNS_OPTIONS_ALL);
@@ -1547,7 +1557,7 @@ dns_launch_wildcard_checks(void)
 void
 dns_launch_correctness_checks(void)
 {
-  static struct event launch_event;
+  static struct event *launch_event = NULL;
   struct timeval timeout;
   if (!get_options()->ServerDNSDetectHijacking)
     return;
@@ -1555,10 +1565,11 @@ dns_launch_correctness_checks(void)
 
   /* Wait a while before launching requests for test addresses, so we can
    * get the results from checking for wildcarding. */
-  evtimer_set(&launch_event, launch_test_addresses, NULL);
+  if (! launch_event)
+    launch_event = tor_evtimer_new(NULL, launch_test_addresses, NULL);
   timeout.tv_sec = 30;
   timeout.tv_usec = 0;
-  if (evtimer_add(&launch_event, &timeout)<0) {
+  if (evtimer_add(launch_event, &timeout)<0) {
     log_warn(LD_BUG, "Couldn't add timer for checking for dns hijacking");
   }
 }

src/or/dnsserv.c

@@ -9,7 +9,14 @@
  **/
 
 #include "or.h"
+#ifdef HAVE_EVENT2_DNS_H
+#include <event2/dns.h>
+#include <event2/dns_compat.h>
+/* XXXX022 this implies we want an improved evdns  */
+#include <event2/dns_struct.h>
+#else
 #include "eventdns.h"
+#endif
 
 /** Helper function: called by evdns whenever the client sends a request to our
  * DNSPort.  We need to eventually answer the request <b>req</b>.

src/or/eventdns.c

@@ -89,6 +89,7 @@
 #include <stdarg.h>
 
 #include "eventdns.h"
+
 #ifdef WIN32
 #include <windows.h>
 #include <winsock2.h>

src/or/main.c

@@ -127,12 +127,10 @@ connection_add(connection_t *conn)
   smartlist_add(connection_array, conn);
 
   if (conn->s >= 0 || conn->linked) {
-    conn->read_event = tor_malloc_zero(sizeof(struct event));
-    conn->write_event = tor_malloc_zero(sizeof(struct event));
-    event_set(conn->read_event, conn->s, EV_READ|EV_PERSIST,
-              conn_read_callback, conn);
-    event_set(conn->write_event, conn->s, EV_WRITE|EV_PERSIST,
-              conn_write_callback, conn);
+    conn->read_event = tor_event_new(tor_libevent_get_base(),
+         conn->s, EV_READ|EV_PERSIST, conn_read_callback, conn);
+    conn->write_event = tor_event_new(tor_libevent_get_base(),
+         conn->s, EV_WRITE|EV_PERSIST, conn_write_callback, conn);
   }
 
   log_debug(LD_NET,"new conn type %s, socket %d, address %s, n_conns %d.",
@@ -393,11 +391,11 @@ connection_start_reading_from_linked_conn(connection_t *conn)
     smartlist_add(active_linked_connection_lst, conn);
     if (!called_loop_once) {
       /* This is the first event on the list; we won't be in LOOP_ONCE mode,
-       * so we need to make sure that the event_loop() actually exits at the
-       * end of its run through the current connections and
-       * lets us activate read events for linked connections. */
+       * so we need to make sure that the event_base_loop() actually exits at
+       * the end of its run through the current connections and lets us
+       * activate read events for linked connections. */
       struct timeval tv = { 0, 0 };
-      event_loopexit(&tv);
+      event_base_loopexit(tor_libevent_get_base(), &tv);
     }
   } else {
     tor_assert(smartlist_isin(active_linked_connection_lst, conn));
@@ -1140,8 +1138,8 @@ second_elapsed_callback(int fd, short event, void *args)
   (void)event;
   (void)args;
   if (!timeout_event) {
-    timeout_event = tor_malloc_zero(sizeof(struct event));
-    evtimer_set(timeout_event, second_elapsed_callback, NULL);
+    timeout_event = tor_evtimer_new(tor_libevent_get_base(),
+                                    second_elapsed_callback, NULL);
     one_second.tv_sec = 1;
     one_second.tv_usec = 0;
   }
@@ -1213,7 +1211,7 @@ second_elapsed_callback(int fd, short event, void *args)
   }
 #endif
 
-  if (evtimer_add(timeout_event, &one_second))
+  if (event_add(timeout_event, &one_second))
     log_err(LD_NET,
             "Error from libevent when setting one-second timeout event");
 }
@@ -1424,20 +1422,16 @@ do_main_loop(void)
 
     /* poll until we have an event, or the second ends, or until we have
      * some active linked connections to trigger events for. */
-    loop_result = event_loop(called_loop_once ? EVLOOP_ONCE : 0);
+    loop_result = event_base_loop(tor_libevent_get_base(),
+                                  called_loop_once ? EVLOOP_ONCE : 0);
 
     /* let catch() handle things like ^c, and otherwise don't worry about it */
     if (loop_result < 0) {
       int e = tor_socket_errno(-1);
       /* let the program survive things like ^z */
       if (e != EINTR && !ERRNO_IS_EINPROGRESS(e)) {
-#ifdef HAVE_EVENT_GET_METHOD
         log_err(LD_NET,"libevent call with %s failed: %s [%d]",
-                event_get_method(), tor_socket_strerror(e), e);
-#else
-        log_err(LD_NET,"libevent call failed: %s [%d]",
-                tor_socket_strerror(e), e);
-#endif
+                tor_libevent_get_method(), tor_socket_strerror(e), e);
         return -1;
 #ifndef MS_WINDOWS
       } else if (e == EINVAL) {
@@ -1704,7 +1698,7 @@ handle_signals(int is_parent)
 {
 #ifndef MS_WINDOWS /* do signal stuff only on Unix */
   int i;
-  static int signals[] = {
+  static const int signals[] = {
     SIGINT,  /* do a controlled slow shutdown */
     SIGTERM, /* to terminate now */
     SIGPIPE, /* otherwise SIGPIPE kills us */
@@ -1716,12 +1710,13 @@ handle_signals(int is_parent)
 #endif
     SIGCHLD, /* handle dns/cpu workers that exit */
     -1 };
-  static struct event signal_events[16]; /* bigger than it has to be. */
+  static struct event *signal_events[16]; /* bigger than it has to be. */
   if (is_parent) {
     for (i = 0; signals[i] >= 0; ++i) {
-      signal_set(&signal_events[i], signals[i], signal_callback,
-                 (void*)(uintptr_t)signals[i]);
-      if (signal_add(&signal_events[i], NULL))
+      signal_events[i] = tor_evsignal_new(
+                       tor_libevent_get_base(), signals[i], signal_callback,
+                       (void*)(uintptr_t)signals[i]);
+      if (event_add(signal_events[i], NULL))
         log_warn(LD_BUG, "Error from libevent when adding event for signal %d",
                  signals[i]);
     }

src/or/or.h

@@ -91,8 +91,7 @@
 #include "util.h"
 #include "torgzip.h"
 #include "address.h"
-
-#include <event.h>
+#include "compat_libevent.h"
 
 /* These signals are defined to help control_signal_act work.
  */
@@ -922,8 +921,8 @@ typedef struct connection_t {
    * connection. */
   unsigned int linked_conn_is_closed:1;
 
-  int s; /**< Our socket; -1 if this connection is closed, or has no
-          * socket. */
+  /** Our socket; -1 if this connection is closed, or has no socket. */
+  evutil_socket_t s;
   int conn_array_index; /**< Index into the global connection array. */
   struct event *read_event; /**< Libevent event structure. */
   struct event *write_event; /**< Libevent event structure. */

src/tools/Makefile.am

@@ -3,16 +3,16 @@ noinst_PROGRAMS =  tor-checkkey
 
 tor_resolve_SOURCES = tor-resolve.c
 tor_resolve_LDFLAGS = @TOR_LDFLAGS_libevent@
-tor_resolve_LDADD = ../common/libor.a -levent @TOR_LIB_WS32@
+tor_resolve_LDADD = ../common/libor.a @TOR_LIB_WS32@
 
 tor_gencert_SOURCES = tor-gencert.c
 tor_gencert_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
         @TOR_LDFLAGS_libevent@
 tor_gencert_LDADD = ../common/libor.a ../common/libor-crypto.a \
-        -lz -lcrypto -levent @TOR_LIB_WS32@ @TOR_LIB_GDI@
+        -lz -lcrypto @TOR_LIB_WS32@ @TOR_LIB_GDI@
 
 tor_checkkey_SOURCES = tor-checkkey.c
 tor_checkkey_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
         @TOR_LDFLAGS_libevent@
 tor_checkkey_LDADD = ../common/libor.a ../common/libor-crypto.a \
-        -lz -lcrypto -levent @TOR_LIB_WS32@ @TOR_LIB_GDI@
+        -lz -lcrypto @TOR_LIB_WS32@ @TOR_LIB_GDI@