Dear Masahiro,
In message 20140930175820.4A3C.AA925319@jp.panasonic.com you wrote:
This happens for example with all but the most recent versions of Yocto based tool chains (inclusing all currently existing versions of the ELDK), which provide a python2 binary in SYSROOT/usr/bin/python2, but do not include the "fnmatch" module.
I'd like to regard the root cause of the problem as ELDK missing fnmatch module.
Yes, you are right. The problem is caused by the fact that the ELDK (and other Yocto based tool chains until very recently) provide their own version of Python2, but without including the fnmatch module.
I think '/usr/bin/env python' is a general strategy to support various platforms where Python might not be installed in /usr/bin directory. (Buildman and Patman have already adopted this way.)
I agree, and I'm fully aware of potential issues - this is why I marked this patch as RFC. I'm looking for a solution which works reasonably well for all.
The situation is, that there is a pretty large number of tool chains out there (and ectively being used in a number of projects), which provide their own Python interpreter, but are lacking the fnmatch module.
As I see it, we have the following options to deal with that:
1) Rewrite genboardscfg.py such that fnmatch is not needed. I have no idea if this is easily possible or how much effort was required to do that.
2) Let the script use the system provided Python binary, asuming that fnmatch is either automatically installed or at least ready available and with minimal effort installable in all recent Linux distros.
3) Create fixes so the users can rebuild the tool chains such that these contain the needed Python modules.
4) For all tool chains that support some form of package management, build and distribute the missing Python modules as upate package.
5) Fix and rebuild tool chains and distribute new versions of the tool chains.
My proposed patch choses option 2), as this appears to require the minimal effort on both the tool chain suppliers and on the U-Boot side.
Best regards,
Wolfgang Denk