Re: [FFmpeg-devel] [PATCH v1] fftools/ffplay: Resolve input file path before processing

[Appaji Chintimi <appaji12368@gmail.com>]

Hello, Can I get some eyes on this please?

On Fri, 16 May 2025 at 01:24, Appaji Chintimi <appaji12368@gmail.com> wrote:
>
> Can you elaborate a bit more why this requires more changes? My understanding is, to check for different cases and handle them differently:
>
> 1. "-" gets replaced with "fd:", and it's passed directly to "input_filename" without resolving.
> 2. if the path contains "://", that too gets passed on without resolving it further (handles http://, https://, ftp:// etc..)
> 3. Only after these two checks, resolve the "filename" and pass on to "input_filename".
>
> On Wed, 14 May 2025 at 23:40, Marton Balint <cus@passwd.hu> wrote:
>>
>>
>>
>> On Wed, 14 May 2025, Nicolas George wrote:
>>
>> > Appaji (HE12025-05-14):
>> >> Fixes ticket: https://trac.ffmpeg.org/ticket/11574
>> >>
>> >> Signed-off-by: Appaji <appaji12368@gmail.com>
>> >> ---
>> >>  fftools/ffplay.c | 13 +++++++++++--
>> >>  1 file changed, 11 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/fftools/ffplay.c b/fftools/ffplay.c
>> >> index 2a572fc3aa..42f0584b55 100644
>> >> --- a/fftools/ffplay.c
>> >> +++ b/fftools/ffplay.c
>> >> @@ -27,6 +27,7 @@
>> >>  #include "config_components.h"
>> >>  #include <math.h>
>> >>  #include <limits.h>
>> >> +#include <stdlib.h>
>> >>  #include <signal.h>
>> >>  #include <stdint.h>
>> >>
>> >> @@ -3623,9 +3624,17 @@ static int opt_input_file(void *optctx, const char *filename)
>> >>                  filename, input_filename);
>> >>          return AVERROR(EINVAL);
>> >>      }
>> >> -    if (!strcmp(filename, "-"))
>> >> +
>> >> +    char resolved_path[PATH_MAX];
>> >> +
>> >> +    if (!realpath(filename, resolved_path)) {
>> >> +        av_log(NULL, AV_LOG_FATAL, "Failed to resolve path for '%s': %s\n", filename, strerror(errno));
>> >> +        return AVERROR(errno);
>> >> +    }
>> >> +
>> >
>> > Hi. Thanks for the patch. Did you test it with non-filenames arguments,
>> > for example http://…?
>> >
>> >> +    if (!strcmp(resolved_path, "-"))
>> >>          filename = "fd:";
>> >
>> > This should happen before resolution.
>> >
>> >> -    input_filename = av_strdup(filename);
>> >> +    input_filename = av_strdup(resolved_path);
>> >>      if (!input_filename)
>> >>          return AVERROR(ENOMEM);
>> >>
>> >
>> > On the whole, I think you are going at it wrong: you are only fixing
>> > this for ffplay, not for ffprobe, ffmpeg and other applications built on
>> > the libraries, and resolving the path can have side effects, for example
>> > if you do not have permission on a parent of the current working
>> > directory.
>> >
>> > IMO, the correct way would be to add a stat() early in the opening of
>> > the file and test the device number. But that requires changing quite a
>> > lot of things.
>>
>> Agreed. You should improve the probing function to fix the ticket, you can
>> do a stat in v4l2_read_probe() in libavdevice/v4l2.c, check if it is a
>> char device and try a V4L2 IOCTL on it to make sure it is a V4L2 device.
>>
>> Regards,
>> Marton
>>
>> >
>> > Regards,
>> >
>> > --
>> >  Nicolas George
>> > _______________________________________________
>> > ffmpeg-devel mailing list
>> > ffmpeg-devel@ffmpeg.org
>> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>> >
>> > To unsubscribe, visit link above, or email
>> > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".