[FFmpeg-devel] [PATCH] lavf/os_support: Add safe win32 dlopen/dlclose/dlsym functions.

[Matt Oliver]

On 31 October 2016 at 05:30, James Almer <jamrial at gmail.com> wrote:

> On 10/30/2016 8:31 AM, Matt Oliver wrote:
> > From 1dc1f59158cfb12d9160ee47342f5742d67ad864 Mon Sep 17 00:00:00 2001
> > From: Matt Oliver <protogonoi at gmail.com>
> > Date: Sun, 30 Oct 2016 15:13:47 +1100
> > Subject: [PATCH] avformat/avisynth.c: Use new safe dlopen code.
> >
> > ---
> >  configure              |  5 ++---
> >  libavformat/avisynth.c | 14 +++++---------
> >  2 files changed, 7 insertions(+), 12 deletions(-)
> >
> > diff --git a/configure b/configure
> > index 5993de5..9feb544 100755
> > --- a/configure
> > +++ b/configure
> > @@ -2850,6 +2850,7 @@ asf_stream_muxer_select="asf_muxer"
> >  avi_demuxer_select="iso_media riffdec exif"
> >  avi_muxer_select="riffenc"
> >  avisynth_demuxer_deps="avisynth"
> > +avisynth_demuxer_deps_any="dlopen LoadLibrary"
> >  avisynth_demuxer_select="riffdec"
>
> With this change and the stuff removed below, avisynth (CONFIG_AVISYNTH)
> will always be enabled if you configure with --enable-avisynth, and only
> avisynth_demuxer will be disabled depending on the presence of dlopen and
> LoadLibrary.
> This is probably not intended, seeing how libavformat/Makefile checks for
> CONFIG_AVISYNTH and not CONFIG_AVISYNTH_DEMUXER in order to compile the
> source file, so you should make it avisynth_deps_any="dlopen LoadLibrary"
> since avisynth_demuxer already depends on avisynth.
>
> Also, consider changing libavformat/Makefile to check for the demuxer
> rather than the library/feature.
>

Changed, I also moved the avisynth stuff up to the external libraries
section of configure


>
> >  caf_demuxer_select="iso_media riffdec"
> >  dash_muxer_select="mp4_muxer"
> > @@ -5417,6 +5418,7 @@ elif check_func dlopen -ldl && check_func dlsym
> -ldl; then
> >      ldl=-ldl
> >  fi
> >
> > +avisynth_demuxer_extralibs='$ldl'
> >  decklink_outdev_extralibs="$decklink_outdev_extralibs $ldl"
> >  decklink_indev_extralibs="$decklink_indev_extralibs $ldl"
> >  frei0r_filter_extralibs='$ldl'
> > @@ -5664,9 +5666,6 @@ fi
> >  enabled avfoundation_indev && { check_header_objcc
> AVFoundation/AVFoundation.h || disable avfoundation_indev; }
> >  enabled avfoundation_indev && { check_lib2 CoreGraphics/CoreGraphics.h
> CGGetActiveDisplayList -framework CoreGraphics ||
> >                                  check_lib2 ApplicationServices/ApplicationServices.h
> CGGetActiveDisplayList -framework ApplicationServices; }
> > -enabled avisynth          && { { check_lib2 "windows.h" LoadLibrary; }
> ||
> > -                               { check_lib2 "dlfcn.h" dlopen -ldl; } ||
> > -                               die "ERROR: LoadLibrary/dlopen not found
> for avisynth"; }
> >  enabled cuda              && { check_lib cuda.h cuInit -lcuda ||
> >                                 die "ERROR: CUDA not found"; }
> >  enabled cuvid             && { add_cflags -I$source_path;
> > diff --git a/libavformat/avisynth.c b/libavformat/avisynth.c
> > index 1acc44f..514cb99 100644
> > --- a/libavformat/avisynth.c
> > +++ b/libavformat/avisynth.c
> > @@ -29,7 +29,7 @@
> >
> >  /* Platform-specific directives for AviSynth vs AvxSynth. */
> >  #ifdef _WIN32
> > -  #include <windows.h>
> > +  #include "compat/w32dlfcn.h"
> >    #undef EXTERN_C
> >    #include "compat/avisynth/avisynth_c.h"
> >    #define AVISYNTH_LIB "avisynth"
> > @@ -39,10 +39,6 @@
> >    #include "compat/avisynth/avxsynth_c.h"
> >    #define AVISYNTH_NAME "libavxsynth"
> >    #define AVISYNTH_LIB AVISYNTH_NAME SLIBSUF
> > -
> > -  #define LoadLibrary(x) dlopen(x, RTLD_NOW | RTLD_LOCAL)
> > -  #define GetProcAddress dlsym
> > -  #define FreeLibrary dlclose
> >  #endif
> >
> >  typedef struct AviSynthLibrary {
> > @@ -118,13 +114,13 @@ static av_cold void avisynth_atexit_handler(void);
> >
> >  static av_cold int avisynth_load_library(void)
> >  {
> > -    avs_library.library = LoadLibrary(AVISYNTH_LIB);
> > +    avs_library.library = dlopen(AVISYNTH_LIB, RTLD_NOW | RTLD_LOCAL);
> >      if (!avs_library.library)
> >          return AVERROR_UNKNOWN;
> >
> >  #define LOAD_AVS_FUNC(name, continue_on_fail)                          \
> >          avs_library.name =
>  \
> > -            (void *)GetProcAddress(avs_library.library, #name);
> \
> > +            (void *)dlsym(avs_library.library, #name);                 \
> >          if (!continue_on_fail && !avs_library.name)
> \
> >              goto fail;
> >
> > @@ -157,7 +153,7 @@ static av_cold int avisynth_load_library(void)
> >      return 0;
> >
> >  fail:
> > -    FreeLibrary(avs_library.library);
> > +    dlclose(avs_library.library);
> >      return AVERROR_UNKNOWN;
> >  }
> >
> > @@ -225,7 +221,7 @@ static av_cold void avisynth_atexit_handler(void)
> >          avisynth_context_destroy(avs);
> >          avs = next;
> >      }
> > -    FreeLibrary(avs_library.library);
> > +    dlclose(avs_library.library);
> >
> >      avs_atexit_called = 1;
> >  }
> > -- 2.10.1.windows.1
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