Proper permissions for Python and packages on OS X Lion

Question

I am running OS X Lion (started on Leopard, and have gone through two upgrades). OS X Lion comes with Python 2.7. At some point, I thought Python and its packages were working together (possibly before my upgrade with Lion).

I can run Python as a non-superuser. However, when I import packages or try running easy_install , for example, I get the following error.

system:distutils $ python
Python 2.7.1 (r271:86832, Jun 16 2011, 16:59:05) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import zope
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/zope/__init__.py", line 1, in <module>
    __import__('pkg_resources').declare_namespace(__name__)
  File "build/bdist.linux-i686/egg/pkg_resources.py", line 698, in <module>
    class Environment(object):
  File "build/bdist.linux-i686/egg/pkg_resources.py", line 701, in Environment
    def __init__(self, search_path=None, platform=get_supported_platform(), python=PY_MAJOR):
  File "build/bdist.linux-i686/egg/pkg_resources.py", line 96, in get_supported_platform
    plat = get_build_platform(); m = macosVersionString.match(plat)
  File "build/bdist.linux-i686/egg/pkg_resources.py", line 222, in get_build_platform
    plat = get_platform()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/util.py", line 165, in get_platform
    "Don't know machine value for archs=%r"%(archs,))
ValueError: Don't know machine value for archs=()
>>> ^D
system:distutils $

When I run it as root or as sudo , everything works fine. All of the directories and files have 0755 or 0644 permissions, respectively.

What should the permissions be for Python and its packages on OS X Lion so you can use it as a normal user? Is the way my permissions are currently configured the default, or did I mess up the permissions along the way.

I realize I can go through the /System/Library/... and the /Library/Python/... directories and change the ownership and permission to me. But that does not seem like that is the correct solution.

Answer 1

For anyone coming here via googling for the error, it's also possible this is not a permissions problem. Rather, it can occur because the environment variables used by Python to determine the (Apple) platform are set incorrectly.

Relevant flags include at least:

'CFLAGS', 'LDFLAGS', 'CPPFLAGS', 'BASECFLAGS', 'BLDSHARED', 'LDSHARED', 'CC', 'CXX', 'PY_CFLAGS', 'PY_LDFLAGS', 'PY_CPPFLAGS', 'PY_CORE_CFLAGS'

Check out the the _osx_support.py file of Python stdlib, and the get_platform_osx function in particular; it's all there.

Answer 2

After struggling for a while, and getting repeatedly frustrated, I figured out two reasons easy_install could fail with this error.

1. I need to have XCode installed (which I already did)
2. I simply went through the code in util.py to find the line that produced the error, and changed the result.

This worked perfectly. I now never receive that error. I have put the diff below for the solution. Please note, I chose 'intel' for the machine type, because with OS X Lion, all PPC support is removed.

I hope this helps someone else.

wintermute:distutils $ pwd
/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils
wintermute:distutils $ diff -U 5  util.py.bad util.py
--- util.py.bad 2012-03-03 15:30:39.000000000 -0500
+++ util.py 2012-03-03 15:32:21.000000000 -0500
@@ -159,12 +159,13 @@
                 elif archs == ('ppc64', 'x86_64'):
                     machine = 'fat64'
                 elif archs == ('i386', 'ppc', 'ppc64', 'x86_64'):
                     machine = 'universal'
                 else:
-                    raise ValueError(
-                       "Don't know machine value for archs=%r"%(archs,))
+                    machine = 'intel'
+                    #raise ValueError(
+                    #   "Don't know machine value for archs=%r"%(archs,))

             elif machine == 'i386':
                 # On OSX the machine type returned by uname is always the
                 # 32-bit variant, even if the executable architecture is
                 # the 64-bit variant
wintermute:distutils $ 

Answer 3

There's something unusual about your Python setup. On my Lion (10.7.3) systems, the Apple-supplied Python 2.7 has this banner and there is no problem importing Zope:

$ /usr/bin/python2.7
Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import zope
>>>

Perhaps you have a pre-release version of parts of Lion installed?