trace: improve error reporting when parsing simpletrace header
When loading a simpletrace binary file we just report
"Not a valid trace file!" which is not very helpful. Report
exactly which field we found to be invalid.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170125161417.31949-9-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/scripts/simpletrace.py b/scripts/simpletrace.py
index 4ca903d..4c99004 100755
--- a/scripts/simpletrace.py
+++ b/scripts/simpletrace.py
@@ -73,10 +73,14 @@
def read_trace_header(fobj):
"""Read and verify trace file header"""
header = read_header(fobj, log_header_fmt)
- if header is None or \
- header[0] != header_event_id or \
- header[1] != header_magic:
+ 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))
log_version = header[2]
if log_version not in [0, 2, 3, 4]:
