Description:
------------
If mod_php4 (precompiled from the web page), with php_gd2.dll extension loaded, is used in Apache/1.3.27 on Windows 2000, createimagefromgif returns black images or only parts of the image, if some pages call it at the same time.

For example:
<?php
header ("Content-type: image/jpeg");
$im="image.gif";
$im1=imagecreatefromgif($im);
imagejpeg($im1);
?>
image.gif can be any gif, some KBs big.

Run in many terminal then something like
while /bin/true; do wget "http://server/skript.php"; done

only a part of the saved images will be ok. If only one images is fetched at a time, all images are ok.

If the skript is used by many users, web browsers also show black images or parts of the image.

I think, the error is in the bundled libgd, in gd_gif_in.c. There global and static variables are used to read the gif, which all threads seem to share. Removing them and storing them in a per Request state, seems to solve the problem for me.

An example patch, which works for me, is at: http://stud4.tuwien.ac.at/~e9925248/php/gd-gif.diff

Martin K?gler
e9925248@stud4.tuwien.ac.at


Reproduce code:
---------------
<?php
header ("Content-type: image/jpeg");
$im="image.gif";
$im1=imagecreatefromgif($im);
imagejpeg($im1);
?>

Expected result:
----------------
The gif-image as jpeg

Actual result:
--------------
If some users use the script at the same time, the image has black parts.