[PATCH 1/3] perf script python: Fix string vs byte array resolving

[Jiri Olsa]

Jirka reported that python code returns all arrays as strings.
This makes impossible to get all items for byte array tracepoint
field containing 0x00 value item.

Fixing this by scanning full length of the array and returning
it as PyByteArray object in case non printable byte is found.

Link: http://lkml.kernel.org/n/tip-22f4vhhz5uytegkggy1on8u3@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 .../util/scripting-engines/trace-event-python.c    | 39 ++++++++++++++++++----
 1 file changed, 33 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index 6ac6b7a33f42..7bd6da80533e 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -386,6 +386,21 @@ exit:
 	return pylist;
 }
 
+static int is_printable_array(char *p, unsigned int len)
+{
+	unsigned int i;
+
+	if (!p || !len || p[len - 1] != 0)
+		return 0;
+
+	len--;
+
+	for (i = 0; i < len; i++) {
+		if (!isprint(p[i]) && !isspace(p[i]))
+			return 0;
+	}
+	return 1;
+}
 
 static void python_process_tracepoint(struct perf_sample *sample,
 				      struct perf_evsel *evsel,
@@ -457,14 +472,26 @@ static void python_process_tracepoint(struct perf_sample *sample,
 		pydict_set_item_string_decref(dict, "common_callchain", callchain);
 	}
 	for (field = event->format.fields; field; field = field->next) {
-		if (field->flags & FIELD_IS_STRING) {
-			int offset;
+		unsigned int offset, len;
+		unsigned long long val;
+
+		if (field->flags & FIELD_IS_ARRAY) {
+			offset = field->offset;
+			len    = field->size;
 			if (field->flags & FIELD_IS_DYNAMIC) {
-				offset = *(int *)(data + field->offset);
+				val     = pevent_read_number(scripting_context->pevent,
+							     data + offset, len);
+				offset  = val;
+				len     = offset >> 16;
 				offset &= 0xffff;
-			} else
-				offset = field->offset;
-			obj = PyString_FromString((char *)data + offset);
+			}
+			if (field->flags & FIELD_IS_STRING &&
+			    is_printable_array(data + offset, len)) {
+				obj = PyString_FromString((char *) data + offset);
+			} else {
+				obj = PyByteArray_FromStringAndSize((const char *) data + offset, len);
+				field->flags &= ~FIELD_IS_STRING;
+			}
 		} else { /* FIELD_IS_NUMERIC */
 			obj = get_field_numeric_entry(event, field, data);
 		}
-- 
2.4.11