[FFmpeg-devel] [PATCH v9 1/1] avformat: Add IPFS protocol support.

[Michael Niedermayer]

On Mon, Mar 28, 2022 at 06:34:33PM +0200, Mark Gaiser wrote:
> On Mon, Mar 28, 2022 at 6:19 PM Michael Niedermayer <michael at niedermayer.cc>
> wrote:
> 
> > On Fri, Mar 18, 2022 at 03:50:05PM +0100, Mark Gaiser wrote:
> > > This patch adds support for:
> > > - ffplay ipfs://<cid>
> > > - ffplay ipns://<cid>
> > >
> > > IPFS data can be played from so called "ipfs gateways".
> > > A gateway is essentially a webserver that gives access to the
> > > distributed IPFS network.
> > >
> > > This protocol support (ipfs and ipns) therefore translates
> > > ipfs:// and ipns:// to a http:// url. This resulting url is
> > > then handled by the http protocol. It could also be https
> > > depending on the gateway provided.
> > >
> > > To use this protocol, a gateway must be provided.
> > > If you do nothing it will try to find it in your
> > > $HOME/.ipfs/gateway file. The ways to set it manually are:
> > > 1. Define a -gateway <url> to the gateway.
> > > 2. Define $IPFS_GATEWAY with the full http link to the gateway.
> > > 3. Define $IPFS_PATH and point it to the IPFS data path.
> > > 4. Have IPFS running in your local user folder (under $HOME/.ipfs).
> > >
> > > Signed-off-by: Mark Gaiser <markg85 at gmail.com>
> > > ---
> > >  configure                 |   2 +
> > >  doc/protocols.texi        |  30 ++++
> > >  libavformat/Makefile      |   2 +
> > >  libavformat/ipfsgateway.c | 310 ++++++++++++++++++++++++++++++++++++++
> > >  libavformat/protocols.c   |   2 +
> > >  5 files changed, 346 insertions(+)
> > >  create mode 100644 libavformat/ipfsgateway.c
> >
> > Theres some trailing whitespace which needs to be removed
> > our git scripts block trailing whitespace in most files
> >
> > [...]
> > > +static int ipfs_close(URLContext *h)
> > > +{
> > > +    IPFSGatewayContext *c = h->priv_data;
> > > +    av_free(c->gateway);
> >
> > this results in a double free
> >
> 
> I believe one of the earlier feedback rounds told me to put it here.
> It's not free'd anywhere else.

==22837== Invalid free() / delete / delete[] / realloc()
==22837==    at 0x4C32D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22837==    by 0x117FF88: av_opt_free (in ffmpeg/ffmpeg_g)
==22837==    by 0x5C58CF: ffurl_closep (in ffmpeg/ffmpeg_g)
==22837==    by 0x5C5AF2: ffurl_close (in ffmpeg/ffmpeg_g)
==22837==    by 0x5CA206: avio_close (in ffmpeg/ffmpeg_g)
==22837==    by 0x3021C0: ffmpeg_cleanup (in ffmpeg/ffmpeg_g)
==22837==    by 0x2F5FA0: exit_program (in ffmpeg/ffmpeg_g)
==22837==    by 0x2E34A1: main (in ffmpeg/ffmpeg_g)
==22837==  Address 0x2ced8760 is 0 bytes inside a block of size 17 free'd
==22837==    at 0x4C32D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22837==    by 0x7372BD: ipfs_close (in ffmpeg/ffmpeg_g)
==22837==    by 0x5C588C: ffurl_closep (in ffmpeg/ffmpeg_g)
==22837==    by 0x5C5AF2: ffurl_close (in ffmpeg/ffmpeg_g)
==22837==    by 0x5CA206: avio_close (in ffmpeg/ffmpeg_g)
==22837==    by 0x3021C0: ffmpeg_cleanup (in ffmpeg/ffmpeg_g)
==22837==    by 0x2F5FA0: exit_program (in ffmpeg/ffmpeg_g)
==22837==    by 0x2E34A1: main (in ffmpeg/ffmpeg_g)
==22837==  Block was alloc'd at
==22837==    at 0x4C31A3F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22837==    by 0x4C33D84: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22837==    by 0x117E120: av_strdup (in ffmpeg/ffmpeg_g)
==22837==    by 0x1181DEF: av_opt_set (in ffmpeg/ffmpeg_g)
==22837==    by 0x118272D: av_opt_set_dict2 (in ffmpeg/ffmpeg_g)
==22837==    by 0x5C598C: ffurl_open_whitelist (in ffmpeg/ffmpeg_g)
==22837==    by 0x5CA4DD: ffio_open_whitelist (in ffmpeg/ffmpeg_g)
==22837==    by 0x6B88FB: io_open_default (in ffmpeg/ffmpeg_g)
==22837==    by 0x5E0E9E: avformat_open_input (in ffmpeg/ffmpeg_g)
==22837==    by 0x2EB32B: open_input_file (in ffmpeg/ffmpeg_g)
==22837==    by 0x2EF00B: ffmpeg_parse_options (in ffmpeg/ffmpeg_g)
==22837==    by 0x2E3301: main (in ffmpeg/ffmpeg_g)


> 
> Then again, in those earlier rounds I was manipulating c-gateway which
> right now isn't the case at all anymore.
> 
> If all that's stopping it from merging is this single line, could you
> perhaps merge it and remove this line while at it?
> I'm kinda reluctant to make another patch and wait 1-2 weeks again...

I do not know why its there or who asked for it to be put there.
I dont want to just remove something while merging that someone else
asked to be added

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Never trust a computer, one day, it may think you are the virus. -- Compn
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