/** Initialize the Libevent library and set up the event base. */
void
tor_libevent_initialize(void)
{
tor_assert(the_event_base == NULL);
#ifdef __APPLE__
if (MACOSX_KQUEUE_IS_BROKEN ||
tor_get_libevent_version(NULL) < V_OLD(1,1,'b')) {
setenv("EVENT_NOKQUEUE","1",1);
}
#endif
#ifdef HAVE_EVENT2_EVENT_H
{
struct event_config *cfg = event_config_new();
tor_assert(cfg);
/* In 0.2.2, we don't use locking at all. Telling Libevent not to try to
* turn it on can avoid a needless socketpair() attempt.
*/
event_config_set_flag(cfg, EVENT_BASE_FLAG_NOLOCK);
the_event_base = event_base_new_with_config(cfg);
event_config_free(cfg);
}
#else
the_event_base = event_init();
#endif
if (!the_event_base) {
log_err(LD_GENERAL, "Unable to initialize Libevent: cannot continue.");
exit(1);
}
#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(), tor_libevent_get_method());
#else
log(LOG_NOTICE, LD_GENERAL,
"Initialized old libevent (version 1.0b or earlier).");
log(LOG_WARN, LD_GENERAL,
"You have a *VERY* old version of libevent. It is likely to be buggy; "
"please build Tor with a more recent version.");
#endif
}
/**
* Compare the current Libevent method and version to a list of versions
* which are known not to work. Warn the user as appropriate.
*/
void
tor_check_libevent_version(const char *m, int server,
const char **badness_out)
{
int buggy = 0, iffy = 0, slow = 0, thread_unsafe = 0;
le_version_t version;
const char *v = NULL;
const char *badness = NULL;
const char *sad_os = "";
version = tor_get_libevent_version(&v);
/* It would be better to disable known-buggy methods rather than warning
* about them. But the problem is that with older versions of Libevent,
* it's not trivial to get them to change their methods once they're
* initialized... and with newer versions of Libevent, they aren't actually
* broken. But we should revisit this if we ever find a post-1.4 version
* of Libevent where we need to disable a given method. */
if (!strcmp(m, "kqueue")) {
if (version < V_OLD(1,1,'b'))
buggy = 1;
} else if (!strcmp(m, "epoll")) {
if (version < V(1,1,0))
iffy = 1;
} else if (!strcmp(m, "poll")) {
if (version < V_OLD(1,0,'e'))
buggy = 1;
if (version < V(1,1,0))
slow = 1;
} else if (!strcmp(m, "select")) {
if (version < V(1,1,0))
slow = 1;
} else if (!strcmp(m, "win32")) {
if (version < V_OLD(1,1,'b'))
buggy = 1;
}
/* Libevent versions before 1.3b do very badly on operating systems with
* user-space threading implementations. */
#if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__)
if (server && version < V_OLD(1,3,'b')) {
thread_unsafe = 1;
sad_os = "BSD variants";
}
#elif defined(__APPLE__) || defined(__darwin__)
if (server && version < V_OLD(1,3,'b')) {
thread_unsafe = 1;
sad_os = "Mac OS X";
}
#endif
if (thread_unsafe) {
log(LOG_WARN, LD_GENERAL,
"Libevent version %s often crashes when running a Tor server with %s. "
"Please use the latest version of libevent (1.3b or later)",v,sad_os);
badness = "BROKEN";
} else if (buggy) {
log(LOG_WARN, LD_GENERAL,
"There are serious bugs in using %s with libevent %s. "
"Please use the latest version of libevent.", m, v);
badness = "BROKEN";
} else if (iffy) {
log(LOG_WARN, LD_GENERAL,
"There are minor bugs in using %s with libevent %s. "
"You may want to use the latest version of libevent.", m, v);
badness = "BUGGY";
} else if (slow && server) {
log(LOG_WARN, LD_GENERAL,
"libevent %s can be very slow with %s. "
"When running a server, please use the latest version of libevent.",
v,m);
badness = "SLOW";
}
*badness_out = badness;
}
/** Initialize the Libevent library and set up the event base. */
void
tor_libevent_initialize(tor_libevent_cfg *torcfg)
{
tor_assert(the_event_base == NULL);
/* some paths below don't use torcfg, so avoid unused variable warnings */
(void)torcfg;
#ifdef __APPLE__
if (MACOSX_KQUEUE_IS_BROKEN ||
tor_get_libevent_version(NULL) < V_OLD(1,1,'b')) {
setenv("EVENT_NOKQUEUE","1",1);
}
#endif
#ifdef HAVE_EVENT2_EVENT_H
{
int attempts = 0;
int using_threads;
struct event_config *cfg;
retry:
++attempts;
using_threads = 0;
cfg = event_config_new();
tor_assert(cfg);
#if defined(_WIN32) && defined(USE_BUFFEREVENTS)
if (! torcfg->disable_iocp) {
evthread_use_windows_threads();
event_config_set_flag(cfg, EVENT_BASE_FLAG_STARTUP_IOCP);
using_iocp_bufferevents = 1;
using_threads = 1;
} else {
using_iocp_bufferevents = 0;
}
#endif
if (!using_threads) {
/* Telling Libevent not to try to turn locking on can avoid a needless
* socketpair() attempt. */
event_config_set_flag(cfg, EVENT_BASE_FLAG_NOLOCK);
}
#if defined(LIBEVENT_VERSION_NUMBER) && LIBEVENT_VERSION_NUMBER >= V(2,0,7)
if (torcfg->num_cpus > 0)
event_config_set_num_cpus_hint(cfg, torcfg->num_cpus);
#endif
#if LIBEVENT_VERSION_NUMBER >= V(2,0,9)
/* We can enable changelist support with epoll, since we don't give
* Libevent any dup'd fds. This lets us avoid some syscalls. */
event_config_set_flag(cfg, EVENT_BASE_FLAG_EPOLL_USE_CHANGELIST);
#endif
the_event_base = event_base_new_with_config(cfg);
event_config_free(cfg);
if (using_threads && the_event_base == NULL && attempts < 2) {
/* This could be a socketpair() failure, which can happen sometimes on
* windows boxes with obnoxious firewall rules. Downgrade and try
* again. */
#if defined(_WIN32) && defined(USE_BUFFEREVENTS)
if (torcfg->disable_iocp == 0) {
log_warn(LD_GENERAL, "Unable to initialize Libevent. Trying again "
"with IOCP disabled.");
} else
#endif
{
log_warn(LD_GENERAL, "Unable to initialize Libevent. Trying again.");
}
torcfg->disable_iocp = 1;
goto retry;
}
}
#else
the_event_base = event_init();
#endif
if (!the_event_base) {
log_err(LD_GENERAL, "Unable to initialize Libevent: cannot continue.");
exit(1);
}
#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(), tor_libevent_get_method());
#else
log(LOG_NOTICE, LD_GENERAL,
"Initialized old libevent (version 1.0b or earlier).");
log(LOG_WARN, LD_GENERAL,
"You have a *VERY* old version of libevent. It is likely to be buggy; "
"please build Tor with a more recent version.");
#endif
#ifdef USE_BUFFEREVENTS
tor_libevent_set_tick_timeout(torcfg->msec_per_tick);
#endif
}
