[PATCH AUTOSEL for 4.14 027/161] tools lib traceevent: Fix get_field_str() for dynamic strings

Sasha Levin
2018-04-09T00:22:47Z

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

[ Upstream commit d777f8de99b05d399c0e4e51cdce016f26bd971b ]

If a field is a dynamic string, get_field_str() returned just the
offset/size value and not the string. Have it parse the offset/size
correctly to return the actual string. Otherwise filtering fails when
trying to filter fields that are dynamic strings.

Reported-by: Gopanapalli Pradeep <prap_hai@yahoo.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20180112004823.146333275@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
tools/lib/traceevent/parse-filter.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 7c214ceb9386..5e10ba796a6f 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -1879,17 +1879,25 @@ static const char *get_field_str(struct filter_arg *arg, struct pevent_record *r
struct pevent *pevent;
unsigned long long addr;
const char *val = NULL;
+ unsigned int size;
char hex[64];

/* If the field is not a string convert it */
if (arg->str.field->flags & FIELD_IS_STRING) {
val = record->data + arg->str.field->offset;
+ size = arg->str.field->size;
+
+ if (arg->str.field->flags & FIELD_IS_DYNAMIC) {
+ addr = *(unsigned int *)val;
+ val = record->data + (addr & 0xffff);
+ size = addr >> 16;
+ }

/*
* We need to copy the data since we can't be sure the field
* is null terminated.
*/
- if (*(val + arg->str.field->size - 1)) {
+ if (*(val + size - 1)) {
/* copy it */
memcpy(arg->str.buffer, val, arg->str.field->size);
/* the buffer is already NULL terminated */
--
2.15.1