LogRateLimiter will be used to keep track of source locations and our
current time-based logging window. It contains an unordered_map and a
m_suppressions_active bool to track source locations. The map is keyed
by std::source_location, so a custom Hash function (SourceLocationHasher)
and custom KeyEqual function (SourceLocationEqual) is provided.
SourceLocationHasher uses CSipHasher(0,0) under the hood to get a
uniform distribution.

A public Reset method is provided so that a scheduler (e.g. the
"b-scheduler" thread) can periodically reset LogRateLimiter's state when
the time window has elapsed.

The LogRateLimiter::Consume method checks if we have enough available
bytes in our rate limiting budget to log an additional string. It
returns a Status enum that denotes the rate limiting status and can
be used by the caller to emit a warning, skip logging, etc.

The Status enum has three states:
- UNSUPPRESSED     (logging was successful)
- NEWLY_SUPPRESSED (logging was succcesful, next log will be suppressed)
- STILL_SUPPRESSED (logging was unsuccessful)

LogLimitStats counts the available bytes left for logging per source
location for the current logging window. It does not track actual source
locations; it is used as a value in m_source_locations.

Also exposes a SuppressionsActive() method so the logger can use
that in a later commit to prefix [*] to logs whenenever suppressions
are active.

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

Github-Pull: bitcoin#32604
Rebased-From: afb9e39

The std::source_location conveniently stores the file name, line number,
and function name of a source code location. We switch to using it instead
of the __func__ identifier and the __FILE__ and __LINE__ macros.

BufferedLog is changed to have a std::source_location member, replacing the
source_file, source_line, and logging_function members. As a result,
MemUsage no longer explicitly counts source_file or logging_function as the
std::source_location memory usage is included in the MallocUsage call.

This also changes the behavior of -logsourcelocations as std::source_location
includes the entire function signature. Because of this, the functional test
feature_config_args.py must be changed to no longer include the function
signature as the function signature can differ across platforms.

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

Github-Pull: bitcoin#32604
Rebased-From: a6a35cc

…ogPrintLevel

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>

Github-Pull: bitcoin#32604
Rebased-From: d541409

Github-Pull: bitcoin#32604
Rebased-From: 4c772cb

Github-Pull: bitcoin#33011
Rebased-From: 616bc22

Co-Authored-By: l0rinc <pap.lorinc@gmail.com>

Github-Pull: bitcoin#33011
Rebased-From: b8e92fb

Co-Authored-By: l0rinc <pap.lorinc@gmail.com>

Github-Pull: bitcoin#33011
Rebased-From: 5f70bc8

Co-Authored-By: stickies-v <stickies-v@protonmail.com>

Github-Pull: bitcoin#33011
Rebased-From: 8319a13

Clean up the noisy LogLimitStats and remove references to the time
window.

Co-Authored-By: stickies-v <stickies-v@protonmail.com>

Github-Pull: bitcoin#33011
Rebased-From: 3c7cae4

… there are suppressions

In LogPrintStr_:
- remove an unnecessary BCLog since we are in the BCLog namespace.
- remove an unnecessary \n when rate limiting is triggered since
  FormatLogStrInPlace will add it.
- move the ratelimit bool into an else if block.
- prefix all log lines with [*] when suppressions exist. Previously this
  was only done if should_ratelimit was true.

In Reset:
- remove an unnecessary \n since FormatLogStrInPlace will add it.
- Change Level::Info to Level::Warning.

Github-Pull: bitcoin#33011
Rebased-From: e8f9c37

This allows us to safely and explicitly manage the dual dependency
on the limiter: one for the Logger, and one for the CScheduler.

Github-Pull: bitcoin#33011
Rebased-From: 3d630c2

Deduplicates repeated usage of the same functionality.

Github-Pull: bitcoin#33011
Rebased-From: 05d7c22

This ensures log tests behave consistently when other tests modify
the log category mask.

Github-Pull: bitcoin#33011
Rebased-From: 350193e

- Add helper functions and structs to improve readability and
  reusability of test code
- Make tests more specific by comparing all produced log lines with
  expected log lines instead of relying on approximations or proxies.

Github-Pull: bitcoin#33011
Rebased-From: 9f3b017

Use -nologratelimit by default in functional tests if the bitcoind
version supports it.

Co-Authored-By: stickies-v <stickies-v@protonmail.com>

Github-Pull: bitcoin#33011
Rebased-From: 5c74a0b

Change time_window from 20s to 1h so Reset is not accidentally called
if the test takes a while.

Change num_lines from 1024 to 10 since LogRateLimiter is parameterized
and does not require logging 1MiB of data.

Co-Authored-By: stickies-v <stickies-v@protonmail.com>

Github-Pull: bitcoin#33211
Rebased-From: 5dda364