[FFmpeg-devel] [PATCH] avfilter/vf_stack: Don't modify const strings

Paul B Mahol onemda at gmail.com
Tue May 14 15:41:28 EEST 2019


On 5/14/19, Gyan <ffmpeg at gyani.pro> wrote:
>
>
> On 14-05-2019 09:45 AM, Andreas Rheinhardt wrote:
>> b3b7ba62 introduced undefined behaviour: A (non-modifiable) string
>> literal has been assigned to a modifiable string; said string was indeed
>> modified later via av_strtok.
>> This of course caused compiler warnings because of the discarded
>> qualifier; these are in particular fixed by this commit.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>> ---
>>   libavfilter/vf_stack.c | 8 +++++---
>>   1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/libavfilter/vf_stack.c b/libavfilter/vf_stack.c
>> index 1455f196a7..4d254e0013 100644
>> --- a/libavfilter/vf_stack.c
>> +++ b/libavfilter/vf_stack.c
>> @@ -84,9 +84,11 @@ static av_cold int init(AVFilterContext *ctx)
>>
>>       if (!strcmp(ctx->filter->name, "xstack")) {
>>           if (!s->layout) {
>> -            if (s->nb_inputs == 2)
>> -                s->layout = "0_0|w0_0";
>> -            else {
>> +            if (s->nb_inputs == 2) {
>> +                s->layout = av_strdup("0_0|w0_0");
>> +                if (!s->layout)
>> +                    return AVERROR(ENOMEM);
>> +            } else {
>>                   av_log(ctx, AV_LOG_ERROR, "No layout specified.\n");
>>                   return AVERROR(EINVAL);
>>               }
>
> Sorry, I missed what was being done with the string later on.
>

Why you pushed something else that what was reviewed?

> Gyan
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