[FFmpeg-devel] [PATCH] tools/graph2dot: Don't use sizeof(AVFilterGraph), check allocation

[Andreas Rheinhardt]

Jan Ekström:
> On Thu, Jul 22, 2021 at 10:05 AM Andreas Rheinhardt
> <andreas.rheinhardt at outlook.com> wrote:
>>
>> Use avfilter_graph_alloc() instead of av_mallocz(sizeof(AVFilterGraph))
>> to allocate an AVFilterGraph; this also properly allocates the graph's
>> internal. The current code just happened to work because it did not
>> make any use of said internal.
>>
>> Also check the allocation; this fixes Coverity #1292528.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
>> ---
>>  tools/graph2dot.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/graph2dot.c b/tools/graph2dot.c
>> index d5c1e4e3c7..fe1eedb9f3 100644
>> --- a/tools/graph2dot.c
>> +++ b/tools/graph2dot.c
>> @@ -113,7 +113,7 @@ int main(int argc, char **argv)
>>      FILE *outfile           = NULL;
>>      FILE *infile            = NULL;
>>      char *graph_string      = NULL;
>> -    AVFilterGraph *graph = av_mallocz(sizeof(AVFilterGraph));
>> +    AVFilterGraph *graph;
> 
> I really prefer initializing all values to something known instead of
> whatever used to be in that memory block before (if calling the
> initializer is possible, right away - otherwise a temporary failure
> value such as nullptr), but I know we differ in opinion regarding
> this, so let's not go further on this :)
> 
I fulfilled your wish; but only because the compiler can optimize it away.

- Andreas