From d1f9259014317baa3bce7db7d4c2e927341e3cae Mon Sep 17 00:00:00 2001 From: Mads Ynddal Date: Tue, 26 Sep 2023 12:34:28 +0200 Subject: [PATCH] simpletrace: improved error handling on struct unpack MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A failed call to `read_header` wouldn't be handled the same for the two different code paths (one path would try to use `None` as a list). Changed to raise exception to be handled centrally. This also allows for easier unpacking, as errors has been filtered out. Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Stefan Hajnoczi Signed-off-by: Mads Ynddal Message-id: 20230926103436.25700-7-mads@ynddal.dk Signed-off-by: Stefan Hajnoczi --- scripts/simpletrace.py | 39 +++++++++++++++------------------------ 1 file changed, 15 insertions(+), 24 deletions(-) diff --git a/scripts/simpletrace.py b/scripts/simpletrace.py index 971b2a0f6a..8aea0d169b 100755 --- a/scripts/simpletrace.py +++ b/scripts/simpletrace.py @@ -37,26 +37,24 @@ def read_header(fobj, hfmt): hlen = struct.calcsize(hfmt) hdr = fobj.read(hlen) if len(hdr) != hlen: - return None + raise ValueError('Error reading header. Wrong filetype provided?') return struct.unpack(hfmt, hdr) def get_record(event_mapping, event_id_to_name, rechdr, fobj): """Deserialize a trace record from a file into a tuple (name, timestamp, pid, arg1, ..., arg6).""" - if rechdr is None: - return None - if rechdr[0] != dropped_event_id: - event_id = rechdr[0] + event_id, timestamp_ns, length, pid = rechdr + if event_id != dropped_event_id: name = event_id_to_name[event_id] - rec = (name, rechdr[1], rechdr[3]) try: event = event_mapping[name] except KeyError as e: - sys.stderr.write('%s event is logged but is not declared ' \ + sys.stderr.write(f'{e} event is logged but is not declared ' \ 'in the trace events file, try using ' \ - 'trace-events-all instead.\n' % str(e)) + 'trace-events-all instead.\n') sys.exit(1) + rec = (name, timestamp_ns, pid) for type, name in event.args: if is_string(type): l = fobj.read(4) @@ -67,9 +65,8 @@ def get_record(event_mapping, event_id_to_name, rechdr, fobj): (value,) = struct.unpack('=Q', fobj.read(8)) rec = rec + (value,) else: - rec = ("dropped", rechdr[1], rechdr[3]) - (value,) = struct.unpack('=Q', fobj.read(8)) - rec = rec + (value,) + (dropped_count,) = struct.unpack('=Q', fobj.read(8)) + rec = ("dropped", timestamp_ns, pid, dropped_count) return rec def get_mapping(fobj): @@ -86,22 +83,16 @@ def read_record(event_mapping, event_id_to_name, fobj): def read_trace_header(fobj): """Read and verify trace file header""" - header = read_header(fobj, log_header_fmt) - if header is None: - raise ValueError('Not a valid trace file!') - if header[0] != header_event_id: - raise ValueError('Not a valid trace file, header id %d != %d' % - (header[0], header_event_id)) - if header[1] != header_magic: - raise ValueError('Not a valid trace file, header magic %d != %d' % - (header[1], header_magic)) + _header_event_id, _header_magic, log_version = read_header(fobj, log_header_fmt) + if _header_event_id != header_event_id: + raise ValueError(f'Not a valid trace file, header id {_header_event_id} != {header_event_id}') + if _header_magic != header_magic: + raise ValueError(f'Not a valid trace file, header magic {_header_magic} != {header_magic}') - log_version = header[2] if log_version not in [0, 2, 3, 4]: - raise ValueError('Unknown version of tracelog format!') + raise ValueError(f'Unknown version {log_version} of tracelog format!') if log_version != 4: - raise ValueError('Log format %d not supported with this QEMU release!' - % log_version) + raise ValueError(f'Log format {log_version} not supported with this QEMU release!') def read_trace_records(event_mapping, event_id_to_name, fobj): """Deserialize trace records from a file, yielding record tuples (event_num, timestamp, pid, arg1, ..., arg6).