[FFmpeg-devel] [PATCH 1/3 v2] doc/examples: Add fffuzz example
Paweł Goliński
golpaw1 at gmail.com
Mon Apr 18 15:02:11 CEST 2016
Hi,
I’ll try to clear some things up. Here it goes:
1. About the copyright thing, kierank didn’t say to add him to copyright section and I’m not sure whether its his code, so I left it as it is.
2. I got instructions not to hook this up to build system just yet, I think one of the reasons is that we’re not sure whether compile this with afl instrumentation (afl-clang-fast command), or just normally. This is something that will be clear later.
3. About failure checks, I guess I’ll add them in next version of the patch.
Also, sorry for ignoring previous email, I discussed the review of my previous patch with kierank so I thought it was enough.
——
Paweł
> Wiadomość napisana przez Michael Niedermayer <michael at niedermayer.cc> w dniu 17.04.2016, o godz. 04:03:
>
> Hi
>
> On Sat, Apr 16, 2016 at 12:12:41AM +0200, Pawel Golinski wrote:
>> There are some afl specific macros inside,
>> to make the example usable with afl fuzzer.
>> ---
>> doc/examples/fffuzz.c | 370 ++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 370 insertions(+)
>> create mode 100644 doc/examples/fffuzz.c
>>
>> diff --git a/doc/examples/fffuzz.c b/doc/examples/fffuzz.c
>> new file mode 100644
>> index 0000000..6672f42
>> --- /dev/null
>> +++ b/doc/examples/fffuzz.c
>> @@ -0,0 +1,370 @@
>> +/*
>> + * Copyright (c) 2012 Stefano Sabatini
>> + * Copyright (c) 2015 Andreas Cadhalpun
>
> there was a review comment about this, please do not ignore review
> comments
> for reference;
>>>> <kierank> the first patch in the patchset is my patch so I can't review it
>>>> would suggest to me that he should be listed in the Copyright too
>
> also when at this, please make sure the author metadata in the commits
> is correct, i dont know who wrote what
>
> also the code is still not hooked up to the build system
>
>
> [...]
>> +/**
>> + * @file
>> + * Demuxing and decoding (a codec/format combination) example.
>> + *
>> + * This can be useful for fuzz testing.
>> + * @example ddcf.c
>> + */
>> +
>> +#include <libavutil/avstring.h>
>> +#include <libavutil/imgutils.h>
>> +#include <libavutil/samplefmt.h>
>> +#include <libavutil/timestamp.h>
>> +#include <libavformat/avformat.h>
>> +
>> +/* needed for decoding video */
>> +static int width, height;
>> +static enum AVPixelFormat pix_fmt;
>> +static uint8_t *video_dst_data[4] = {NULL};
>> +static int video_dst_linesize[4];
>> +static int video_dst_bufsize;
>> +
>> +static int decode_packet(AVCodecContext *dec_ctx, FILE *dst_file, AVFrame *frame, int *got_frame, int *frame_count, AVPacket *pkt)
>> +{
>> + int ret = -1;
>> + *got_frame = 0;
>> + AVSubtitle sub;
>> + unsigned i, j, k, l;
>> +
>> + if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
>> + /* decode video frame */
>> + ret = avcodec_decode_video2(dec_ctx, frame, got_frame, pkt);
>> + if (ret < 0) {
>> + fprintf(stderr, "Error decoding video frame (%s)\n", av_err2str(ret));
>> + return ret;
>> + }
>> +
>> + if (*got_frame) {
>> +
>> + if (frame->width != width || frame->height != height ||
>> + frame->format != pix_fmt) {
>> + fprintf(stderr, "Error: input video width/height/format changed:\n"
>> + "old: width = %d, height = %d, format = %s\n"
>> + "new: width = %d, height = %d, format = %s\n",
>> + width, height, av_get_pix_fmt_name(pix_fmt),
>> + dec_ctx->width, dec_ctx->height,
>> + av_get_pix_fmt_name(dec_ctx->pix_fmt));
>> + return -1;
>> + }
>> +
>> + printf("video_frame n:%d coded_n:%d pts:%s\n",
>> + *frame_count, frame->coded_picture_number,
>> + av_ts2timestr(frame->pts, &dec_ctx->time_base));
>> +
>> + /* copy decoded frame to destination buffer:
>> + * this is required since rawvideo expects non aligned data */
>> + av_image_copy(video_dst_data, video_dst_linesize,
>> + (const uint8_t **)(frame->data), frame->linesize,
>> + pix_fmt, width, height);
>> + *frame_count += 1;
>> +
>> + /* write to rawvideo file */
>> + fwrite(video_dst_data[0], 1, video_dst_bufsize, dst_file);
>> + }
>> + } else if (dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
>> + /* decode audio frame */
>> + ret = avcodec_decode_audio4(dec_ctx, frame, got_frame, pkt);
>> + if (ret < 0) {
>> + fprintf(stderr, "Error decoding audio frame (%s)\n", av_err2str(ret));
>> + return ret;
>> + }
>
>> + /* Some audio decoders decode only part of the packet, and have to be
>> + * called again with the remainder of the packet data.
>> + * Sample: fate-suite/lossless-audio/luckynight-partial.shn
>> + * Also, some decoders might over-read the packet. */
>> + ret = FFMIN(ret, pkt->size);
>
> overreads should not be ignored silently
>
>
> [...]
>> +static int open_codec_context(AVCodecContext **dec_ctx, AVFormatContext *fmt_ctx, char *codec)
>> +{
>> + int ret = -1;
>> + AVCodec *dec = avcodec_find_decoder_by_name(codec);
>> + AVDictionary *opts = NULL;
>> + unsigned int i;
>> +
>> + for (i = 0; i < fmt_ctx->nb_streams && i < INT_MAX; i += 1) {
>> + if (fmt_ctx->streams[i]->codec) {
>> + if (!dec || (fmt_ctx->streams[i]->codec->codec_id == dec->id)) {
>> + *dec_ctx = fmt_ctx->streams[i]->codec;
>> + ret = 0;
>> + break;
>> + }
>> + }
>> + }
>> +
>> + if (ret < 0) {
>> + fprintf(stderr, "Could not find stream\n");
>> + } else {
>> + /* find decoder for the stream */
>> + if (!dec)
>> + dec = avcodec_find_decoder((*dec_ctx)->codec_id);
>> + if (!dec) {
>> + fprintf(stderr, "Failed to find decoder\n");
>> + return -1;
>> + }
>> +
>
>> + /* Init the decoders, with or without reference counting */
>> + av_dict_set(&opts, "refcounted_frames", "1", 0);
>> + av_dict_set(&opts, "strict", "-2", 0);
>> + av_dict_set(&opts, "codec_whitelist", codec, 0);
>> + av_dict_set(&opts, "thread_type", "slice", 0);
>
> missing failure checks
>
>
> [...]
> --
> Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Everything should be made as simple as possible, but not simpler.
> -- Albert Einstein
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