[FFmpeg-devel] [PATCH 1/8] libavdevice/v4l2.c: fix build warning

Guo, Yejun yejun.guo at intel.com
Wed Feb 24 17:15:14 EET 2021



> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Anton
> Khirnov
> Sent: 2021年2月24日 22:05
> To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH 1/8] libavdevice/v4l2.c: fix build warning
> 
> Quoting Guo, Yejun (2021-02-20 08:22:11)
> > Here is the warning message:
> > src/libavdevice/v4l2.c: In function ‘v4l2_get_device_list’:
> > src/libavdevice/v4l2.c:1054:58: warning: ‘%s’ directive output may be
> truncated writing up to 255 bytes into a region of size 251
> [-Wformat-truncation=]
> >          snprintf(device_name, sizeof(device_name), "/dev/%s",
> entry->d_name);
> >                                                           ^~
> > src/libavdevice/v4l2.c:1054:9: note: ‘snprintf’ output between 6 and 261
> bytes into a destination of size 256
> >          snprintf(device_name, sizeof(device_name), "/dev/%s",
> entry->d_name);
> >
> >
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~
> > ---
> > This patch set fixes build warnings during make on my system with gcc
> > version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04) with config option:
> > --disable-optimizations --enable-libx264 --enable-libx265 --enable-gpl
> --enable-libvpx --enable-libmfx --extra-cflags="-Wno-deprecated-declarations"
> >
> > I also tried '-Wall -Werror', there are many many issues starting from
> > configure. It is a long term task, let's fix one by one when have time.
> >
> >  libavdevice/v4l2.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/libavdevice/v4l2.c b/libavdevice/v4l2.c index
> > 365bacd771..15ade26eed 100644
> > --- a/libavdevice/v4l2.c
> > +++ b/libavdevice/v4l2.c
> > @@ -1046,7 +1046,7 @@ static int v4l2_get_device_list(AVFormatContext
> *ctx, AVDeviceInfoList *device_l
> >          return ret;
> >      }
> >      while ((entry = readdir(dir))) {
> > -        char device_name[256];
> > +        char device_name[261];
> 
> sizeof(entry->d_name) + 5
> would be eaiser to read IMO

yes, will update the patches, and send all with V2 except patch 7 which has been fixed with 1c9e53d7


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