Decode reserved SEL record types as standard events

Some BMCs (e.g. AMI) log events using spec-reserved record types like
0x04 with a standard system event record layout.  Previously only type
0x02 was decoded, leaving such entries with no usable data and tripping
the generic OEM handler.  Follow ipmitool and treat all types below 0xc0
as standard format.  If the body of a reserved type turns out not to
follow the standard layout, fall back to passing it through raw instead
of aborting the whole log retrieval.

confluent_server/aiohmi/ipmi/events.py

@@ -519,12 +519,25 @@ class EventHandler(object):
         selentry = bytearray(origselentry)
         event = {}
         event['record_id'] = struct.unpack_from('<H', origselentry[:2])[0]
-        if selentry[2] == 2 or (0xc0 <= selentry[2] <= 0xdf):
+        if selentry[2] < 0xe0 and len(selentry) >= 7:
             # Either standard, or at least the timestamp is standard
             event['timecode'] = struct.unpack_from('<I', buffer(selentry[3:7])
                                                    )[0]
-        if selentry[2] == 2:  # ipmi defined standard format
-            self._decode_standard_event(selentry[7:], event)
+        if selentry[2] < 0xc0:
+            # ipmi defined standard format (0x02); like ipmitool, extend the
+            # same treatment to reserved types some BMCs use (e.g. AMI 0x04)
+            try:
+                self._decode_standard_event(selentry[7:], event)
+            except Exception:
+                if selentry[2] == 2:
+                    raise
+                # a reserved type that does not actually follow the standard
+                # layout; discard any partially decoded fields and pass it
+                # through raw rather than aborting the fetch
+                for key in list(event):
+                    if key not in ('record_id', 'timecode'):
+                        del event[key]
+                event['oemdata'] = selentry[3:]
         elif 0xc0 <= selentry[2] <= 0xdf:
             event['oemid'] = selentry[7:10]
             event['oemdata'] = selentry[10:]