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Refactor to remove n_libevent_errors 

We cleared this value in second_elapsed_callback.  But what were we
using it for?  For detecting if Libevent returned EINVAL too often!
We already have a way to detect too-frequent events, and that's with
a ratelim_t.  Refactor the code to use that instead.  Closes ticket
26016.
This commit is contained in:
Nick Mathewson 2018-05-03 12:44:00 -04:00
parent 5e0316142f
commit b0e5757710
2 changed files with 14 additions and 22 deletions
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4
changes/ticket26016 Normal file
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@ -0,0 +1,4 @@
o Code simplification and refactoring:
- Use our standard rate-limiting code to deal with excessive libevent
failures, rather than the hand-rolled logic we had before.
Closes ticket 26016.

32
src/or/main.c
View File

@ -2493,8 +2493,6 @@ hs_service_callback(time_t now, const or_options_t *options)
/** Timer: used to invoke second_elapsed_callback() once per second. */
static periodic_timer_t *second_timer = NULL;
/** Number of libevent errors in the last second: we die if we get too many. */
static int n_libevent_errors = 0;
/** Last time that second_elapsed_callback was called. */
static time_t current_second = 0;
@ -2512,8 +2510,6 @@ second_elapsed_callback(periodic_timer_t *timer, void *arg)
(void)timer;
(void)arg;
n_libevent_errors = 0;
/* log_notice(LD_GENERAL, "Tick."); */
now = time(NULL);
update_approx_time(now);
@ -2558,21 +2554,6 @@ systemd_watchdog_callback(periodic_timer_t *timer, void *arg)
}
#endif /* defined(HAVE_SYSTEMD_209) */
#ifndef _WIN32
/** Called when a possibly ignorable libevent error occurs; ensures that we
* don't get into an infinite loop by ignoring too many errors from
* libevent. */
static int
got_libevent_error(void)
{
if (++n_libevent_errors > 8) {
log_err(LD_NET, "Too many libevent errors in one second; dying");
return -1;
}
return 0;
}
#endif /* !defined(_WIN32) */
#define UPTIME_CUTOFF_FOR_NEW_BANDWIDTH_TEST (6*60*60)
/** Called when our IP address seems to have changed. <b>at_interface</b>
@ -2914,6 +2895,11 @@ do_main_loop(void)
return run_main_loop_until_done();
}
#ifndef _WIN32
/** Rate-limiter for EINVAL-type libevent warnings. */
static ratelim_t libevent_error_ratelim = RATELIM_INIT(10);
#endif
/**
* Run the main loop a single time. Return 0 for "exit"; -1 for "exit with
* error", and 1 for "run this again."
@ -2979,9 +2965,12 @@ run_main_loop_once(void)
return -1;
#ifndef _WIN32
} else if (e == EINVAL) {
log_warn(LD_NET, "EINVAL from libevent: should you upgrade libevent?");
if (got_libevent_error())
log_fn_ratelim(&libevent_error_ratelim, LOG_WARN, LD_NET,
"EINVAL from libevent: should you upgrade libevent?");
if (libevent_error_ratelim.n_calls_since_last_time > 8) {
log_err(LD_NET, "Too many libevent errors, too fast: dying");
return -1;
}
#endif /* !defined(_WIN32) */
} else {
tor_assert_nonfatal_once(! ERRNO_IS_EINPROGRESS(e));
@ -3663,7 +3652,6 @@ tor_free_all(int postfork)
should_init_bridge_stats = 1;
dns_honesty_first_time = 1;
heartbeat_callback_first_time = 1;
n_libevent_errors = 0;
current_second = 0;
if (!postfork) {