log: Add rate limiting to LogPrintf, LogInfo, LogWarning, LogError, LogPrintLevel

To mitigate disk-filling attacks caused by unsafe usages of LogPrintf and
friends, we rate-limit them by passing a should_ratelimit bool that
eventually makes its way to LogPrintStr which may call
LogRateLimiter::Consume. The rate limiting is accomplished by
adding a LogRateLimiter member to BCLog::Logger which tracks source
code locations for the given logging window.

Every hour, a source location can log up to 1MiB of data. Source
locations that exceed the limit will have their logs suppressed for the
rest of the window determined by m_limiter.

This change affects the public LogPrintLevel function if called with
a level >= BCLog::Level::Info.

The UpdateTipLog function has been changed to use the private LogPrintLevel_
macro with should_ratelimit set to false. This allows UpdateTipLog to log
during IBD without hitting the rate limit.

Note that on restart, a source location that was rate limited before the
restart will be able to log until it hits the rate limit again.

Co-Authored-By: Niklas Gogge <n.goeggi@gmail.com>
Co-Authored-By: stickies-v <stickies-v@protonmail.com>

src/init.cpp

@@ -1378,6 +1378,11 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         }
     }, std::chrono::minutes{5});
 
+    LogInstance().SetRateLimiting(std::make_unique<BCLog::LogRateLimiter>(
+        [&scheduler](auto func, auto window) { scheduler.scheduleEvery(std::move(func), window); },
+        BCLog::RATELIMIT_MAX_BYTES,
+        1h));
+
     assert(!node.validation_signals);
     node.validation_signals = std::make_unique<ValidationSignals>(std::make_unique<SerialTaskRunner>(scheduler));
     auto& validation_signals = *node.validation_signals;