There's now an notifier::Modifiable interface class that class
supposed to signal modifications are to be derived from. This takes
the place of the former MutableValue class and also unifies how Val
and IDs signal modifications.
Scripting errors/mistakes now consistently generate a runtime error
which have the behavior of unwinding the call stack all the way out of
the current event handler.
Before, such errors were not treated consistently and either aborted
the process entirely or emitted a message while continuing to execute
subsequent statements without well-defined behavior (possibly causing
a cascade of errors).
The previous behavior also would only unwind out of the current
function (if within a function body), not out the current event
handler, which is especially problematic for functions that return
a value: the caller is essentially left a mess with no way to deal
with it.
This also changes the behavior of the startup/initialization process
to abort if there's errors during bro_init() rather than continue one
to the main run loop. The `allow_init_errors` option may change this
new, default behavior.
- 'when' statements were problematic when used in a function/event/hook
that had local variables with an assigned function value. This was
because 'when' blocks operate on a clone of the frame and the cloning
process serializes locals and the serialization of functions had an
infinite cycle in it (ID -> BroFunc -> ID -> BroFunc ...). The ID
was only used for the function name and type information, so
refactoring Func and subclasses to depend on those two things instead
fixes the issue.
- 'return when' blocks, specifically, didn't work whenever execution
of the containing function's body does another function call before
reaching the 'return when' block, because of an assertion. This was
was due to logic in CallExpr::Eval always clearing the CallExpr
associated with the Frame after doing the call, instead of restoring
any previous CallExpr, which the code in Trigger::Eval expected to
have available.
- An assert could be reached when the condition of a 'when' statement
depended on checking the value of global state variables. The assert
in Trigger::QueueTrigger that checks that the Trigger isn't disabled
would get hit because Trigger::Eval/Timeout disable themselves after
running, but don't unregister themselves from the NotifierRegistry,
which keeps calling QueueTrigger for every state access of the global.
The Logger class is now in charge of reporting all errors, warnings,
informational messages, weirds, and syslogs. All other components
route their messages through the global bro_logger singleton.
The Logger class comes with these reporting methods:
void Message(const char* fmt, ...);
void Warning(const char* fmt, ...);
void Error(const char* fmt, ...);
void FatalError(const char* fmt, ...); // Terminate Bro.
void Weird(const char* name);
[ .. some more Weird() variants ... ]
void Syslog(const char* fmt, ...);
void InternalWarning(const char* fmt, ...);
void InternalError(const char* fmt, ...); // Terminates Bro.
See Logger.h for more information on these.
Generally, the reporting now works as follows:
- All non-fatal message are reported in one of two ways:
(1) At startup (i.e., before we start processing packets),
they are logged to stderr.
(2) During processing, they turn into events:
event log_message%(msg: string, location: string%);
event log_warning%(msg: string, location: string%);
event log_error%(msg: string, location: string%);
The script level can then handle them as desired.
If we don't have an event handler, we fall back to
reporting on stderr.
- All fatal errors are logged to stderr and Bro terminates
immediately.
- Syslog(msg) directly syslogs, but doesn't do anything else.
The three main types of messages can also be generated on the
scripting layer via new Log::* bifs:
Log::error(msg: string);
Log::warning(msg: string);
Log::message(msg: string);
These pass through the bro_logger as well and thus are handled in the
same way. Their output includes location information.
More changes:
- Removed the alarm statement and the alarm_hook event.
- Adapted lots of locations to use the bro_logger, including some
of the messages that were previously either just written to
stdout, or even funneled through the alarm mechanism.
- No distinction anymore between Error() and RunTime(). There's
now only one class of errors; the line was quite blurred already
anyway.
- util.h: all the error()/warn()/message()/run_time()/pinpoint()
functions are gone. Use the bro_logger instead now.
- Script errors are formatted a bit differently due to the
changes. What I've seen so far looks ok to me, but let me know
if there's something odd.
Notes:
- The default handlers for the new log_* events are just dummy
implementations for now since we need to integrate all this into
the new scripts anyway.
- I'm not too happy with the names of the Logger class and its
instance bro_logger. We now have a LogMgr as well, which makes
this all a bit confusing. But I didn't have a good idea for
better names so I stuck with them for now.
Perhaps we should merge Logger and LogMgr?
addresses. Rather than crashing, we warn the user once and then
always time out the call. This addresses #291, and a #355 is new
ticket scheduling fixing the actual problem to later.
