On Mon, 2013-01-21 at 13:44 +0100, Jiri Olsa wrote:
> 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 <jo...@redhat.com>
> Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
> Cc: Steven Rostedt <rost...@goodmis.org>
> Cc: Corey Ashford <cjash...@linux.vnet.ibm.com>
> Cc: Frederic Weisbecker <fweis...@gmail.com>
> Cc: Ingo Molnar <mi...@elte.hu>
> Cc: Namhyung Kim <namhy...@kernel.org>
> Cc: Paul Mackerras <pau...@samba.org>
> Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
> ---
> 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;
This is only used in this function (the field_dynamic_elem_size() is
only called here). Can we not add the field->type_dyn, and just use a
local variable here. You just need to make sure you free it correctly.
-- Steve
> 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;
--
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