This is the mail archive of the cygwin-patches mailing list for the Cygwin project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH 3/4] dlopen: on x/lib search x/bin if exe is in x/bin


Hi Michael,

On Aug 31 20:07, Michael Haubenwallner wrote:
> citing https://cygwin.com/ml/cygwin-developers/2016-08/msg00020.html
> > Consider the file /usr/bin/cygz.dll:
> > - dlopen (libz.so)            success
> > - dlopen (/usr/bin/libz.so)   success
> > - dlopen (/usr/lib/libz.so)   fails
> 
> * dlfcn.c (dlopen): For dlopen("x/lib/N"), when the application
> executable is in "x/bin/", search for "x/bin/N" before "x/lib/N".
> ---
>  winsup/cygwin/dlfcn.cc | 36 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 35 insertions(+), 1 deletion(-)
> 
> diff --git a/winsup/cygwin/dlfcn.cc b/winsup/cygwin/dlfcn.cc
> index e592512..f8b8743 100644
> --- a/winsup/cygwin/dlfcn.cc
> +++ b/winsup/cygwin/dlfcn.cc
> @@ -153,6 +153,25 @@ collect_basenames (pathfinder::basenamelist & basenames,
>    basenames.appendv (basename, baselen, ext, extlen, NULL);
>  }
>  
> +/* Identify dir of current executable into exedirbuf using wpathbuf buffer.
> +   Return length of exedirbuf on success, or zero on error. */
> +static int
> +get_exedir (char * exedirbuf, wchar_t * wpathbuf)
> +{
> +  /* Unless we have a special cygwin loader, there is no such thing like
> +     DT_RUNPATH on Windows we can use to search for dlls, except for the
> +     directory of the main executable. */
> +  GetModuleFileNameW (NULL, wpathbuf, NT_MAX_PATH);
> +  wchar_t * lastwsep = wcsrchr (wpathbuf, L'\\');
> +  if (!lastwsep)
> +    return 0;
> +  *lastwsep = L'\0';
> +  *exedirbuf = '\0';
> +  if (cygwin_conv_path (CCP_WIN_W_TO_POSIX, wpathbuf, exedirbuf, NT_MAX_PATH))
> +    return 0;
> +  return strlen (exedirbuf);
> +}

You could just use the global variable program_invocation_name.  If in
doubt, use the Windows path global_progname and convert it to full POSIX
via cygwin_conv_path.

>  extern "C" void *
>  dlopen (const char *name, int flags)
>  {
> @@ -184,13 +203,28 @@ dlopen (const char *name, int flags)
>        /* handle for the named library */
>        path_conv real_filename;
>        wchar_t *wpath = tp.w_get ();
> +      char *cpath = tp.c_get ();
>  
>        pathfinder finder (allocator, basenames); /* eats basenames */
>  
>        if (have_dir)
>  	{
> +	  int dirlen = basename - 1 - name;
> +
> +	  /* if the specified dir is x/lib, and the current executable
> +	     dir is x/bin, do the /lib -> /bin mapping, which is the
> +	     same actually as adding the executable dir */
> +	  if (dirlen >= 4 && !strncmp (name + dirlen - 4, "/lib", 4))
> +	    {
> +	      int exedirlen = get_exedir (cpath, wpath);
> +	      if (exedirlen == dirlen &&
> +		  !strncmp (cpath, name, dirlen - 4) &&
> +		  !strcmp (cpath + dirlen - 4, "/bin"))
> +		finder.add_searchdir (cpath, exedirlen);
> +	    }
> +
>  	  /* search the specified dir */
> -	  finder.add_searchdir (name, basename - 1 - name);
> +	  finder.add_searchdir (name, dirlen);
>  	}
>        else
>  	{
> -- 
> 2.7.3

Rest looks ok.


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

Attachment: signature.asc
Description: PGP signature


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]