Re: lt_dlopen an uninstalled library

[Bob Friesenhahn]

On Thu, 25 Nov 2021, ilya Basin wrote:

> Hi Bob. I configured the GM build with '--with-modules', ran `make check` 
> successfully. Then truncated the built .so files inside the 'coders/' dir to 
> break it. Then reproduced the failure in gdb
>
>    [il@reallin GM]$ export 
> MAGICK_CONFIGURE_PATH='/home/il/builds/GM/config:/home/il/builds/GM/config'
>    [il@reallin GM]$ export MAGICK_CODER_MODULE_PATH='/home/il/builds/GM/coders'
>    [il@reallin GM]$ gdb --args ./tests/.libs/lt-constitute -storagetype char 
> /home/il/builds/GM/tests/input_truecolor.miff bgr
>
> So it turned out that the test program relies on the full path to 
> the modules dir passed to the program and it calls lt_dlopen() with 
> the full path. I guess I'll have to set the test environment in 
> Makefile.am. Thanks.

It is interesting that this is what was causing problems for you. 
Loading modules is an extremely security-sensitive issue so it makes 
sense to require that the specified path be absolute, or written like 
./foo.la.

Regardless, GraphicsMagick does some things differently than perhaps 
the original libtool/libltdl objectives since it tries not to be too 
dependent on libltdl and it has its own module loader smarts.

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
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