[Qt-interest] Linux Deployment using rpath and $ORIGIN

[Joshua Grauman]

Hello all,

I've read the Qt docs about deploying Qt under Linux. It gives the following 
three ways to deploy the libraries when using dynamic linking. I was wondering 
if the best option isn't even mentioned here. I just read that rpath can take 
$ORIGIN as an option which looks for libraries in the directory of the 
executable. Wouldn't that avoid all the disadvantages listed below, and not 
require the use of a startup script separate from the executable? Couldn't a 
simple tool called linuxdeployqt (similar to the Mac one) be created to set the 
rpath of the executable to $ORIGIN, and copy the libs to that directory? 
Wouldn't this possibly also avoid the setuid problem listed below?

Thanks!

Josh


>From the docs:

You can install the Qt libraries in one of the system library paths (e.g. 
/usr/lib on most systems).

You can pass a predetermined path to the -rpath command-line option when 
linking the application. This will tell the dynamic linker to look in this 
directory when starting your application.

You can write a startup script for your application, where you modify the 
dynamic linker configuration (e.g. adding your application's directory to the 
LD_LIBRARY_PATH environment variable. Note: If your application will be running 
with "Set user ID on execution," and if it will be owned by root, then 
LD_LIBRARY_PATH will be ignored on some platforms. In this case, use of the 
LD_LIBRARY_PATH approach is not an option).


The disadvantage of the first approach is that the user must have super user 
privileges. The disadvantage of the second approach is that the user may not 
have privileges to install into the predetemined path. In either case, the 
users don't have the option of installing to their home directory. We recommend 
using the third approach since it is the most flexible.