[FFmpeg-devel] [PATCH v1 1/2] avformat/utils: make avformat_free_context safety

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Fri Nov 29 09:53:00 EET 2019


Steven Liu:
> set the AVformatContext to NULL use av_freep before
> avformat_free_context return
> 
> Suggested-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
> ---
>  doc/examples/muxing.c            |  2 +-
>  doc/examples/remuxing.c          |  2 +-
>  doc/examples/transcode_aac.c     |  4 ++--
>  doc/examples/transcoding.c       |  2 +-
>  fftools/ffmpeg.c                 |  2 +-
>  libavdevice/avdevice.c           |  2 +-
>  libavdevice/utils.c              |  2 +-
>  libavformat/avformat.h           |  2 +-
>  libavformat/dashdec.c            |  4 ++--
>  libavformat/dashenc.c            |  2 +-
>  libavformat/fifo.c               |  2 +-
>  libavformat/hdsenc.c             |  2 +-
>  libavformat/hls.c                |  4 ++--
>  libavformat/hlsenc.c             |  4 ++--
>  libavformat/img2enc.c            |  6 +++---
>  libavformat/mov.c                |  2 +-
>  libavformat/movenchint.c         |  2 +-
>  libavformat/mpegtsenc.c          |  2 +-
>  libavformat/mux.c                |  2 +-
>  libavformat/rtpenc_chain.c       |  4 ++--
>  libavformat/rtpenc_mpegts.c      |  8 ++++----
>  libavformat/rtsp.c               |  2 +-
>  libavformat/sapenc.c             |  2 +-
>  libavformat/segment.c            |  6 +++---
>  libavformat/smoothstreamingenc.c |  2 +-
>  libavformat/tee.c                |  2 +-
>  libavformat/tests/fifo_muxer.c   |  2 +-
>  libavformat/tests/movenc.c       |  2 +-
>  libavformat/utils.c              | 10 +++++-----
>  libavformat/webm_chunk.c         |  2 +-
>  tools/target_dem_fuzzer.c        |  2 +-
>  tools/uncoded_frame.c            |  2 +-
>  32 files changed, 48 insertions(+), 48 deletions(-)
> 
> diff --git a/doc/examples/muxing.c b/doc/examples/muxing.c
> index 9af9aae483..a151f9cd67 100644
> --- a/doc/examples/muxing.c
> +++ b/doc/examples/muxing.c
> @@ -661,7 +661,7 @@ int main(int argc, char **argv)
>          avio_closep(&oc->pb);
>  
>      /* free the stream */
> -    avformat_free_context(oc);
> +    avformat_free_context(&oc);
>  
>      return 0;
>  }
> diff --git a/doc/examples/remuxing.c b/doc/examples/remuxing.c
> index 9e4d1031b4..fce66c3d80 100644
> --- a/doc/examples/remuxing.c
> +++ b/doc/examples/remuxing.c
> @@ -178,7 +178,7 @@ end:
>      /* close output */
>      if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
>          avio_closep(&ofmt_ctx->pb);
> -    avformat_free_context(ofmt_ctx);
> +    avformat_free_context(&ofmt_ctx);
>  
>      av_freep(&stream_mapping);
>  
> diff --git a/doc/examples/transcode_aac.c b/doc/examples/transcode_aac.c
> index e0c76f5b35..82c3610e39 100644
> --- a/doc/examples/transcode_aac.c
> +++ b/doc/examples/transcode_aac.c
> @@ -238,7 +238,7 @@ static int open_output_file(const char *filename,
>  cleanup:
>      avcodec_free_context(&avctx);
>      avio_closep(&(*output_format_context)->pb);
> -    avformat_free_context(*output_format_context);
> +    avformat_free_context(output_format_context);
>      *output_format_context = NULL;
>      return error < 0 ? error : AVERROR_EXIT;
>  }
> @@ -874,7 +874,7 @@ cleanup:
>          avcodec_free_context(&output_codec_context);
>      if (output_format_context) {
>          avio_closep(&output_format_context->pb);
> -        avformat_free_context(output_format_context);
> +        avformat_free_context(&output_format_context);
>      }
>      if (input_codec_context)
>          avcodec_free_context(&input_codec_context);
> diff --git a/doc/examples/transcoding.c b/doc/examples/transcoding.c
> index e48837cbd2..662dc7e02a 100644
> --- a/doc/examples/transcoding.c
> +++ b/doc/examples/transcoding.c
> @@ -611,7 +611,7 @@ end:
>      avformat_close_input(&ifmt_ctx);
>      if (ofmt_ctx && !(ofmt_ctx->oformat->flags & AVFMT_NOFILE))
>          avio_closep(&ofmt_ctx->pb);
> -    avformat_free_context(ofmt_ctx);
> +    avformat_free_context(&ofmt_ctx);
>  
>      if (ret < 0)
>          av_log(NULL, AV_LOG_ERROR, "Error occurred: %s\n", av_err2str(ret));
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 27f68933f8..c7fa6ccf44 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -539,7 +539,7 @@ static void ffmpeg_cleanup(int ret)
>          s = of->ctx;
>          if (s && s->oformat && !(s->oformat->flags & AVFMT_NOFILE))
>              avio_closep(&s->pb);
> -        avformat_free_context(s);
> +        avformat_free_context(&s);
>          av_dict_free(&of->opts);
>  
>          av_freep(&output_files[i]);
> diff --git a/libavdevice/avdevice.c b/libavdevice/avdevice.c
> index 72e1b67887..46a9e85c1d 100644
> --- a/libavdevice/avdevice.c
> +++ b/libavdevice/avdevice.c
> @@ -221,7 +221,7 @@ static int list_devices_for_context(AVFormatContext *s, AVDictionary *options,
>      ret = avdevice_list_devices(s, device_list);
>    fail:
>      av_dict_free(&tmp);
> -    avformat_free_context(s);
> +    avformat_free_context(&s);
>      return ret;
>  }
>  
> diff --git a/libavdevice/utils.c b/libavdevice/utils.c
> index ccd7318012..1b06387fd3 100644
> --- a/libavdevice/utils.c
> +++ b/libavdevice/utils.c
> @@ -54,6 +54,6 @@ int ff_alloc_input_device_context(AVFormatContext **avctx, AVInputFormat *iforma
>      *avctx = s;
>      return 0;
>    error:
> -    avformat_free_context(s);
> +    avformat_free_context(&s);
>      return ret;
>  }
> diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> index d4d9a3b06e..b524e20392 100644
> --- a/libavformat/avformat.h
> +++ b/libavformat/avformat.h
> @@ -2135,7 +2135,7 @@ AVFormatContext *avformat_alloc_context(void);
>   * Free an AVFormatContext and all its streams.
>   * @param s context to free
>   */
> -void avformat_free_context(AVFormatContext *s);
> +void avformat_free_context(AVFormatContext **s);
>  
>  /**
>   * Get the AVClass for AVFormatContext. It can be used in combination with
> diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
> index d001c5b76d..7b15043811 100644
> --- a/libavformat/dashdec.c
> +++ b/libavformat/dashdec.c
> @@ -1919,7 +1919,7 @@ static int reopen_demux_for_component(AVFormatContext *s, struct representation
>      avio_ctx_buffer  = av_malloc(INITIAL_BUFFER_SIZE);
>      if (!avio_ctx_buffer ) {
>          ret = AVERROR(ENOMEM);
> -        avformat_free_context(pls->ctx);
> +        avformat_free_context(&pls->ctx);
>          pls->ctx = NULL;
>          goto fail;
>      }
> @@ -1939,7 +1939,7 @@ static int reopen_demux_for_component(AVFormatContext *s, struct representation
>      ret = av_probe_input_buffer(&pls->pb, &in_fmt, "", NULL, 0, 0);
>      if (ret < 0) {
>          av_log(s, AV_LOG_ERROR, "Error when loading first fragment, playlist %d\n", (int)pls->rep_idx);
> -        avformat_free_context(pls->ctx);
> +        avformat_free_context(&pls->ctx);
>          pls->ctx = NULL;
>          goto fail;
>      }
> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> index 8c28fb6b6e..8296b9da93 100644
> --- a/libavformat/dashenc.c
> +++ b/libavformat/dashenc.c
> @@ -588,7 +588,7 @@ static void dash_free(AVFormatContext *s)
>                  avio_close(os->ctx->pb);
>          }
>          ff_format_io_close(s, &os->out);
> -        avformat_free_context(os->ctx);
> +        avformat_free_context(&os->ctx);
>          for (j = 0; j < os->nb_segments; j++)
>              av_free(os->segments[j]);
>          av_free(os->segments);
> diff --git a/libavformat/fifo.c b/libavformat/fifo.c
> index b403ba717b..29fdf81474 100644
> --- a/libavformat/fifo.c
> +++ b/libavformat/fifo.c
> @@ -605,7 +605,7 @@ static void fifo_deinit(AVFormatContext *avf)
>      FifoContext *fifo = avf->priv_data;
>  
>      av_dict_free(&fifo->format_options);
> -    avformat_free_context(fifo->avf);
> +    avformat_free_context(&fifo->avf);
>      av_thread_message_queue_free(&fifo->queue);
>      if (fifo->overflow_flag_lock_initialized)
>          pthread_mutex_destroy(&fifo->overflow_flag_lock);
> diff --git a/libavformat/hdsenc.c b/libavformat/hdsenc.c
> index 46f0026bce..767a579f07 100644
> --- a/libavformat/hdsenc.c
> +++ b/libavformat/hdsenc.c
> @@ -146,7 +146,7 @@ static void hds_free(AVFormatContext *s)
>              av_write_trailer(os->ctx);
>          if (os->ctx)
>              avio_context_free(&os->ctx->pb);
> -        avformat_free_context(os->ctx);
> +        avformat_free_context(&os->ctx);
>          av_freep(&os->metadata);
>          for (j = 0; j < os->nb_extra_packets; j++)
>              av_freep(&os->extra_packets[j]);
> diff --git a/libavformat/hls.c b/libavformat/hls.c
> index 0b1582b2b5..95c4a117b8 100644
> --- a/libavformat/hls.c
> +++ b/libavformat/hls.c
> @@ -1923,7 +1923,7 @@ static int hls_read_header(AVFormatContext *s)
>          pls->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);
>          if (!pls->read_buffer){
>              ret = AVERROR(ENOMEM);
> -            avformat_free_context(pls->ctx);
> +            avformat_free_context(&pls->ctx);
>              pls->ctx = NULL;
>              goto fail;
>          }
> @@ -1939,7 +1939,7 @@ static int hls_read_header(AVFormatContext *s)
>               * avformat_open_input fails below, it frees and zeros the
>               * context, so it doesn't need any special treatment like this. */
>              av_log(s, AV_LOG_ERROR, "Error when loading first segment '%s'\n", pls->segments[0]->url);
> -            avformat_free_context(pls->ctx);
> +            avformat_free_context(&pls->ctx);
>              pls->ctx = NULL;
>              goto fail;
>          }
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index f90016901a..f0af70e40f 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -2486,10 +2486,10 @@ static void hls_free_variant_streams(struct HLSContext *hls)
>          if (vtt_oc) {
>              av_freep(&vs->vtt_basename);
>              av_freep(&vs->vtt_m3u8_name);
> -            avformat_free_context(vtt_oc);
> +            avformat_free_context(&vtt_oc);
>          }
>  
> -        avformat_free_context(vs->avf);
> +        avformat_free_context(&vs->avf);
>  
>          hls_free_segments(vs->segments);
>          hls_free_segments(vs->old_segments);
> diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
> index bec4bf81dd..70f8cda706 100644
> --- a/libavformat/img2enc.c
> +++ b/libavformat/img2enc.c
> @@ -162,7 +162,7 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
>              return ret;
>          st = avformat_new_stream(fmt, NULL);
>          if (!st) {
> -            avformat_free_context(fmt);
> +            avformat_free_context(&fmt);
>              return AVERROR(ENOMEM);
>          }
>          st->id = pkt->stream_index;
> @@ -174,11 +174,11 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
>              (ret = av_interleaved_write_frame(fmt, &pkt2))                < 0 ||
>              (ret = av_write_trailer(fmt))                                 < 0) {
>              av_packet_unref(&pkt2);
> -            avformat_free_context(fmt);
> +            avformat_free_context(&fmt);
>              return ret;
>          }
>          av_packet_unref(&pkt2);
> -        avformat_free_context(fmt);
> +        avformat_free_context(&fmt);
>      } else {
>          avio_write(pb[0], pkt->data, pkt->size);
>      }
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 7553a7fdfc..c514bbeaef 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -7290,7 +7290,7 @@ static int mov_read_close(AVFormatContext *s)
>      }
>  
>      if (mov->dv_demux) {
> -        avformat_free_context(mov->dv_fctx);
> +        avformat_free_context(&mov->dv_fctx);
>          mov->dv_fctx = NULL;
>      }
>  
> diff --git a/libavformat/movenchint.c b/libavformat/movenchint.c
> index 964026ec71..f010b85ee5 100644
> --- a/libavformat/movenchint.c
> +++ b/libavformat/movenchint.c
> @@ -468,5 +468,5 @@ void ff_mov_close_hinting(MOVTrack *track)
>          av_write_trailer(rtp_ctx);
>          ffio_free_dyn_buf(&rtp_ctx->pb);
>      }
> -    avformat_free_context(rtp_ctx);
> +    avformat_free_context(&rtp_ctx);
>  }
> diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
> index 9f8f1715c9..ce7781f919 100644
> --- a/libavformat/mpegtsenc.c
> +++ b/libavformat/mpegtsenc.c
> @@ -1814,7 +1814,7 @@ static void mpegts_deinit(AVFormatContext *s)
>          if (ts_st) {
>              av_freep(&ts_st->payload);
>              if (ts_st->amux) {
> -                avformat_free_context(ts_st->amux);
> +                avformat_free_context(&ts_st->amux);
>                  ts_st->amux = NULL;
>              }
>          }
> diff --git a/libavformat/mux.c b/libavformat/mux.c
> index 411cca3fb2..5e3cac7d13 100644
> --- a/libavformat/mux.c
> +++ b/libavformat/mux.c
> @@ -202,7 +202,7 @@ nomem:
>      av_log(s, AV_LOG_ERROR, "Out of memory\n");
>      ret = AVERROR(ENOMEM);
>  error:
> -    avformat_free_context(s);
> +    avformat_free_context(&s);
>      return ret;
>  }
>  
> diff --git a/libavformat/rtpenc_chain.c b/libavformat/rtpenc_chain.c
> index e6b603db70..f3ff4f55db 100644
> --- a/libavformat/rtpenc_chain.c
> +++ b/libavformat/rtpenc_chain.c
> @@ -94,7 +94,7 @@ int ff_rtp_chain_mux_open(AVFormatContext **out, AVFormatContext *s,
>          } else if (rtpctx->pb) {
>              ffio_free_dyn_buf(&rtpctx->pb);
>          }
> -        avformat_free_context(rtpctx);
> +        avformat_free_context(&rtpctx);
>          return ret;
>      }
>  
> @@ -102,7 +102,7 @@ int ff_rtp_chain_mux_open(AVFormatContext **out, AVFormatContext *s,
>      return 0;
>  
>  fail:
> -    avformat_free_context(rtpctx);
> +    avformat_free_context(&rtpctx);
>      if (handle)
>          ffurl_close(handle);
>      return ret;
> diff --git a/libavformat/rtpenc_mpegts.c b/libavformat/rtpenc_mpegts.c
> index 7d7377db7a..59750785ce 100644
> --- a/libavformat/rtpenc_mpegts.c
> +++ b/libavformat/rtpenc_mpegts.c
> @@ -35,11 +35,11 @@ static int rtp_mpegts_write_close(AVFormatContext *s)
>      if (chain->mpegts_ctx) {
>          av_write_trailer(chain->mpegts_ctx);
>          ffio_free_dyn_buf(&chain->mpegts_ctx->pb);
> -        avformat_free_context(chain->mpegts_ctx);
> +        avformat_free_context(&chain->mpegts_ctx);
>      }
>      if (chain->rtp_ctx) {
>          av_write_trailer(chain->rtp_ctx);
> -        avformat_free_context(chain->rtp_ctx);
> +        avformat_free_context(&chain->rtp_ctx);
>      }
>      return 0;
>  }
> @@ -104,9 +104,9 @@ fail:
>      if (mpegts_ctx) {
>          ffio_free_dyn_buf(&mpegts_ctx->pb);
>          av_dict_free(&mpegts_ctx->metadata);
> -        avformat_free_context(mpegts_ctx);
> +        avformat_free_context(&mpegts_ctx);
>      }
> -    avformat_free_context(rtp_ctx);
> +    avformat_free_context(&rtp_ctx);
>      rtp_mpegts_write_close(s);
>      return ret;
>  }
> diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
> index 859defa592..f99fbebed7 100644
> --- a/libavformat/rtsp.c
> +++ b/libavformat/rtsp.c
> @@ -755,7 +755,7 @@ void ff_rtsp_undo_setup(AVFormatContext *s, int send_packets)
>                  } else {
>                      avio_closep(&rtpctx->pb);
>                  }
> -                avformat_free_context(rtpctx);
> +                avformat_free_context(&rtpctx);
>              } else if (CONFIG_RTPDEC && rt->transport == RTSP_TRANSPORT_RDT)
>                  ff_rdt_parse_close(rtsp_st->transport_priv);
>              else if (CONFIG_RTPDEC && rt->transport == RTSP_TRANSPORT_RTP)
> diff --git a/libavformat/sapenc.c b/libavformat/sapenc.c
> index f9afab0c33..2e18f06829 100644
> --- a/libavformat/sapenc.c
> +++ b/libavformat/sapenc.c
> @@ -50,7 +50,7 @@ static int sap_write_close(AVFormatContext *s)
>              continue;
>          av_write_trailer(rtpctx);
>          avio_closep(&rtpctx->pb);
> -        avformat_free_context(rtpctx);
> +        avformat_free_context(&rtpctx);
>          s->streams[i]->priv_data = NULL;
>      }
>  
> diff --git a/libavformat/segment.c b/libavformat/segment.c
> index e3082063d8..b8a25aed9d 100644
> --- a/libavformat/segment.c
> +++ b/libavformat/segment.c
> @@ -244,7 +244,7 @@ static int segment_start(AVFormatContext *s, int write_header)
>      int err = 0;
>  
>      if (write_header) {
> -        avformat_free_context(oc);
> +        avformat_free_context(&oc);
>          seg->avf = NULL;
>          if ((err = segment_mux_init(s)) < 0)
>              return err;
> @@ -662,7 +662,7 @@ static void seg_free(AVFormatContext *s)
>  {
>      SegmentContext *seg = s->priv_data;
>      ff_format_io_close(seg->avf, &seg->list_pb);
> -    avformat_free_context(seg->avf);
> +    avformat_free_context(&seg->avf);
>      seg->avf = NULL;
>  }
>  
> @@ -1031,7 +1031,7 @@ fail:
>          cur = next;
>      }
>  
> -    avformat_free_context(oc);
> +    avformat_free_context(&oc);
>      seg->avf = NULL;
>      return ret;
>  }
> diff --git a/libavformat/smoothstreamingenc.c b/libavformat/smoothstreamingenc.c
> index 2faf1e7897..c9279f2d77 100644
> --- a/libavformat/smoothstreamingenc.c
> +++ b/libavformat/smoothstreamingenc.c
> @@ -183,7 +183,7 @@ static void ism_free(AVFormatContext *s)
>              av_write_trailer(os->ctx);
>          if (os->ctx && os->ctx->pb)
>              avio_context_free(&os->ctx->pb);
> -        avformat_free_context(os->ctx);
> +        avformat_free_context(&os->ctx);
>          av_freep(&os->private_str);
>          for (j = 0; j < os->nb_fragments; j++)
>              av_freep(&os->fragments[j]);
> diff --git a/libavformat/tee.c b/libavformat/tee.c
> index d91993354b..6d252cb396 100644
> --- a/libavformat/tee.c
> +++ b/libavformat/tee.c
> @@ -140,7 +140,7 @@ static int close_slave(TeeSlave *tee_slave)
>      av_freep(&tee_slave->bsfs);
>  
>      ff_format_io_close(avf, &avf->pb);
> -    avformat_free_context(avf);
> +    avformat_free_context(&avf);
>      tee_slave->avf = NULL;
>      return ret;
>  }
> diff --git a/libavformat/tests/fifo_muxer.c b/libavformat/tests/fifo_muxer.c
> index 5127a8aadb..80effb1a7c 100644
> --- a/libavformat/tests/fifo_muxer.c
> +++ b/libavformat/tests/fifo_muxer.c
> @@ -236,7 +236,7 @@ static int run_test(const TestCase *test)
>  
>  end:
>      printf("%s: %s\n", test->test_name, ret < 0 ? "fail" : "ok");
> -    avformat_free_context(oc);
> +    avformat_free_context(&oc);
>      av_dict_free(&opts);
>      return ret;
>  }
> diff --git a/libavformat/tests/movenc.c b/libavformat/tests/movenc.c
> index 1d15d97ad9..3da0abcf68 100644
> --- a/libavformat/tests/movenc.c
> +++ b/libavformat/tests/movenc.c
> @@ -346,7 +346,7 @@ static void finish(void)
>  {
>      av_write_trailer(ctx);
>      avio_context_free(&ctx->pb);
> -    avformat_free_context(ctx);
> +    avformat_free_context(&ctx);
>      ctx = NULL;
>  }
>  
> diff --git a/libavformat/utils.c b/libavformat/utils.c
> index 0461aa83ec..67e083a2f6 100644
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c
> @@ -685,7 +685,7 @@ fail:
>      av_dict_free(&tmp);
>      if (s->pb && !(s->flags & AVFMT_FLAG_CUSTOM_IO))
>          avio_closep(&s->pb);
> -    avformat_free_context(s);
> +    avformat_free_context(&s);
>      *ps = NULL;
>      return ret;
>  }
> @@ -4430,9 +4430,10 @@ void ff_free_stream(AVFormatContext *s, AVStream *st)
>      free_stream(&s->streams[ --s->nb_streams ]);
>  }
>  
> -void avformat_free_context(AVFormatContext *s)
> +void avformat_free_context(AVFormatContext **in)
>  {
>      int i;
> +    AVFormatContext *s = *in;
>  
>      if (!s)
>          return;
> @@ -4468,8 +4469,7 @@ void avformat_free_context(AVFormatContext *s)
>      flush_packet_queue(s);
>      av_freep(&s->internal);
>      av_freep(&s->url);
> -    av_free(s);
> -    s = NULL;
> +    av_freep(&s);
>  }
>  
>  void avformat_close_input(AVFormatContext **ps)
> @@ -4493,7 +4493,7 @@ void avformat_close_input(AVFormatContext **ps)
>          if (s->iformat->read_close)
>              s->iformat->read_close(s);
>  
> -    avformat_free_context(s);
> +    avformat_free_context(&s);
>  
>      *ps = NULL;
>  
> diff --git a/libavformat/webm_chunk.c b/libavformat/webm_chunk.c
> index 4e2ce21a79..278b8379b4 100644
> --- a/libavformat/webm_chunk.c
> +++ b/libavformat/webm_chunk.c
> @@ -258,7 +258,7 @@ static int webm_chunk_write_trailer(AVFormatContext *s)
>  fail:
>      oc->streams = NULL;
>      oc->nb_streams = 0;
> -    avformat_free_context(oc);
> +    avformat_free_context(&oc);
>      return ret;
>  }
>  
> diff --git a/tools/target_dem_fuzzer.c b/tools/target_dem_fuzzer.c
> index 409599636d..eb54091273 100644
> --- a/tools/target_dem_fuzzer.c
> +++ b/tools/target_dem_fuzzer.c
> @@ -136,7 +136,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
>      if (ret < 0) {
>          av_freep(&fuzzed_pb->buffer);
>          av_freep(&fuzzed_pb);
> -        avformat_free_context(avfmt);
> +        avformat_free_context(&avfmt);
>          return 0;
>      }
>  
> diff --git a/tools/uncoded_frame.c b/tools/uncoded_frame.c
> index 3f850d344d..5903382df4 100644
> --- a/tools/uncoded_frame.c
> +++ b/tools/uncoded_frame.c
> @@ -264,7 +264,7 @@ fail:
>              if (st->mux) {
>                  if (st->mux->pb)
>                      avio_closep(&st->mux->pb);
> -                avformat_free_context(st->mux);
> +                avformat_free_context(&st->mux);
>              }
>          }
>      }
> 
1. This is both an ABI as well as an API break and so this is
absolutely unacceptable. Instead, avformat_free_context() should be
deprecated (but kept!) and a new function avformat_free_context2()
should be added.
2. Your patch is not based upon git master:

> -    av_free(s);
> -    s = NULL;
> +    av_freep(&s);

master doesn't have s = NULL;
3. Version bump and API changes should be in the same patch.
4. Some callers already reset the freed AVFormatContext pointers to NULL:

> -    avformat_free_context(seg->avf);
> +    avformat_free_context(&seg->avf);
>      seg->avf = NULL;

In this case, the resets will become redundant and should be removed.
5. I am actually unsure whether the new function is worth the effort.

- Andreas


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