Re: [Bug-AUCTeX] 11.86; pngs not being generated by preview-latex

[Stefan Husmann]

Am 13.10.2010 18:46, schrieb Ralf Angeli:
> * Clark Taylor (2010-10-13) writes:
> 
>> Your patch solved the problem.  It works with gs9.00 and your patch.
> 
> Thanks for testing.  Also to Stefan.
> 
> Below you can find a patch which should solve the problem without
> introducing a security issue.  At least I hope.  It would be nice if
> somebody with some knowledge of Ghostscript could review it.
> 
> The idea is that while Ghostscript is started with -dDELAYSAFER, SAFER
> mode is enabled as soon as reading is permitted for the required files.
> This is done with .locksafe.  The .setsafe statement in the original
> value of `preview-gs-init-string' should not be executed after that, so
> the the PermitFile... parameters should not be reset to empty arrays.  I
> kept the .setsafe for the case without fast conversion.  (All this is
> done after gs is started.  An alternative would be to do a `-dDELAYSAFER
> -c '<</PermitFileReading...' -dSAFER'.  But this clashes a bit with the
> custmizability of the `preview-gs-options'.)
> 
> A propos fast conversion, I'm not sure yet if it is enough to set the
> file permissions in `preview-prepare-fast-conversion' or if this has to
> be done earlier, .e.g in `preview-gs-open'.
> 
> 
> --- preview.el        18 Jun 2009 19:20:46 -0000      1.284
> +++ preview.el        13 Oct 2010 16:28:42 -0000
> @@ -355,7 +355,7 @@
>    :group 'preview-gs
>    :type 'string)
>  
> -(defcustom preview-gs-options '("-q" "-dSAFER" "-dNOPAUSE"
> +(defcustom preview-gs-options '("-q" "-dDELAYSAFER" "-dNOPAUSE"
>                               "-DNOPLATFONTS" "-dPrinted"
>                               "-dTextAlphaBits=4"
>                               "-dGraphicsAlphaBits=4")
> @@ -1066,14 +1066,21 @@
>  
>  (defun preview-prepare-fast-conversion ()
>    "This fixes up all parameters for fast conversion."
> -  (let ((file (if (consp (car preview-ps-file))
> -               (if (consp (caar preview-ps-file))
> -                   (car (last (caar preview-ps-file)))
> -                 (caar preview-ps-file))
> -             (car preview-ps-file))))
> +  (let* ((file (if (consp (car preview-ps-file))
> +                (if (consp (caar preview-ps-file))
> +                    (car (last (caar preview-ps-file)))
> +                  (caar preview-ps-file))
> +              (car preview-ps-file)))
> +      (all-files (if (and (consp (car preview-ps-file))
> +                          (consp (caar preview-ps-file)))
> +                     (caar preview-ps-file)
> +                   (list file))))
>      (setq preview-gs-dsc (preview-dsc-parse file))
>      (setq preview-gs-init-string
> -       (concat preview-gs-init-string
> +       (concat (format "{<</PermitFileReading[%s]>> setuserparams \
> +.locksafe} stopped pop "
> +                       (mapconcat 'preview-ps-quote-filename all-files ""))
> +               preview-gs-init-string
>                 (format "[%s(r)file]aload exch %s .runandhide aload pop "
>                         (preview-ps-quote-filename file)
>                         (preview-gs-dsc-cvx 0 preview-gs-dsc))))))
> 
> 
Hello,

also the new patch works fine here. From what you said in your last post, it 
also should be save enough. Thank you very much for your quick and helpful 
responses.

Best regards Stefan