[PATCH] tools lib traceevent: Handle dynamic array's element size properly

From: Jiri Olsa
Date: Mon Jan 21 2013 - 07:44:23 EST


Fixing the dynamic array format field parsing.

Currently the event_read_fields function could segfault while parsing
dynamic array other than string type. The reason is the event->pevent
does not need to be set and gets dereferenced unconditionaly.

Also adding proper initialization of field->elementsize based on the
parsed dynamic type.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
tools/lib/traceevent/event-parse.c | 40 +++++++++++++++++++++++++++++++++++---
tools/lib/traceevent/event-parse.h | 1 +
2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index f504619..d682df2 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1223,6 +1223,34 @@ static int field_is_long(struct format_field *field)
return 0;
}

+static unsigned int field_dynamic_elem_size(struct format_field *field)
+{
+ /* This covers all FIELD_IS_STRING types. */
+ static struct {
+ char *type;
+ unsigned int size;
+ } table[] = {
+ { "u8", 1 },
+ { "u16", 2 },
+ { "u32", 4 },
+ { "u64", 8 },
+ { "s8", 1 },
+ { "s16", 2 },
+ { "s32", 4 },
+ { "s64", 8 },
+ { "char", 1 },
+ { },
+ };
+ int i;
+
+ for (i = 0; table[i].type; i++) {
+ if (!strcmp(table[i].type, field->type_dyn))
+ return table[i].size;
+ }
+
+ return 0;
+}
+
static int event_read_fields(struct event_format *event, struct format_field **fields)
{
struct format_field *field = NULL;
@@ -1390,7 +1418,7 @@ static int event_read_fields(struct event_format *event, struct format_field **f
field->type = new_type;
strcat(field->type, " ");
strcat(field->type, field->name);
- free_token(field->name);
+ field->type_dyn = field->name;
strcat(field->type, brackets);
field->name = token;
type = read_token(&token);
@@ -1477,10 +1505,14 @@ static int event_read_fields(struct event_format *event, struct format_field **f
if (field->flags & FIELD_IS_ARRAY) {
if (field->arraylen)
field->elementsize = field->size / field->arraylen;
+ else if (field->flags & FIELD_IS_DYNAMIC)
+ field->elementsize = field_dynamic_elem_size(field);
else if (field->flags & FIELD_IS_STRING)
field->elementsize = 1;
- else
- field->elementsize = event->pevent->long_size;
+ else if (field->flags & FIELD_IS_LONG)
+ field->elementsize = event->pevent ?
+ event->pevent->long_size :
+ sizeof(long);
} else
field->elementsize = field->size;

@@ -1496,6 +1528,7 @@ fail:
fail_expect:
if (field) {
free(field->type);
+ free(field->type_dyn);
free(field->name);
free(field);
}
@@ -5500,6 +5533,7 @@ static void free_format_fields(struct format_field *field)
while (field) {
next = field->next;
free(field->type);
+ free(field->type_dyn);
free(field->name);
free(field);
field = next;
diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index 7be7e89..4d54af2 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -174,6 +174,7 @@ struct format_field {
struct format_field *next;
struct event_format *event;
char *type;
+ char *type_dyn;
char *name;
int offset;
int size;
--
1.7.11.7

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