Re: [RFC PATCH 0/2] libtraceevent/perf: Add support for trace-cmd plugins

[Namhyung Kim <namhyung@kernel.org>]

On Tue, 19 Jun 2012 07:54:42 -0400, Steven Rostedt wrote:
> We could simply check if all the characters in the array passes
> 'isprint()' and if it does then print the string, otherwise print the
> hex. Do this for all events, and if it one fails, then mark it always to
> print hex.
>

Ok, checking it at parse time is not possible because we cannot access
to its data. You meant something like this?


diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 853b604b6240..7dae44b74e0b 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -3655,6 +3655,16 @@ static void print_mac_arg(struct trace_seq *s, int mac, void *data, int size,
        trace_seq_printf(s, fmt, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
 }
 
+static int is_printable_array(char *p, unsigned int len)
+{
+       unsigned int i;
+
+       for (i = 0; i < len && p[i]; i++)
+               if (!isprint(p[i]))
+                       return 0;
+       return 1;
+}
+
 static void print_event_fields(struct trace_seq *s, void *data, int size,
                               struct event_format *event)
 {
@@ -3674,7 +3684,8 @@ static void print_event_fields(struct trace_seq *s, void *data, int size,
                                len = offset >> 16;
                                offset &= 0xffff;
                        }
-                       if (field->flags & FIELD_IS_STRING) {
+                       if ((field->flags & FIELD_IS_STRING) &&
+                           is_printable_array(data + offset, len)) {
                                trace_seq_printf(s, "%s", (char *)data + offset);
                        } else {
                                trace_seq_puts(s, "ARRAY[");
@@ -3685,6 +3696,7 @@ static void print_event_fields(struct trace_seq *s, void *data, int size,
                                                         *((unsigned char *)data + offset + i));
                                }
                                trace_seq_putc(s, ']');
+                               field->flags &= ~FIELD_IS_STRING;
                        }
                } else {
                        val = pevent_read_number(event->pevent, data + field->offset,