[FFmpeg-devel] [PATCH v2 1/1] libavformat/img2enc.c: rm warning ‘.tmp’ directive output may be truncated

[Marton Balint]

On Mon, 4 Aug 2025, Michael Niedermayer wrote:

> On Thu, Jul 31, 2025 at 04:21:35PM +0800, Cai Fan wrote:
>> Signed-off-by: Cai Fan <caifan0425 at 163.com>
>> ---
>>  libavformat/img2enc.c | 7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
>> index 41638d92b8..9a5718a8da 100644
>> --- a/libavformat/img2enc.c
>> +++ b/libavformat/img2enc.c
>> @@ -180,7 +180,12 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
>>      }
>>      for (i = 0; i < 4; i++) {
>>          av_dict_copy(&options, img->protocol_opts, 0);
>> -        snprintf(img->tmp[i], sizeof(img->tmp[i]), "%s.tmp", filename);
>> +        int len = snprintf(img->tmp[i], sizeof(img->tmp[i]), "%s.tmp", filename);
>> +        if (len < 0 || len >= sizeof(img->tmp[i])) {
>> +            av_log(s, AV_LOG_ERROR, "filename '%s' exceeds buffer size %zu\n", filename, sizeof(img->tmp[i]));
>> +            ret = AVERROR(EINVAL);
>> +            goto fail;
>> +        }
>
> is there a reason this doesnt use av_asprintf() ?
> that is allocate as needed

Actually I did that extra step and more:

https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20077

So I guess this patch is now obsolete, sorry about that, but it was a 
relatively low hanging fruit.

Regards,
Marton