Python 2.6 makes .pyc/.pyo bytecode files executable

[phdru]

BPO	6070
Nosy	@loewis, @brettcannon, @birkenfeld, @phdru, @tjguk, @bitdancer
Files	import_patch2.patch issue6070.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/bitdancer'
closed_at = <Date 2009-07-19.02:29:25.451>
created_at = <Date 2009-05-20.10:58:48.034>
labels = ['interpreter-core', 'type-bug']
title = 'Python 2.6 makes .pyc/.pyo bytecode files executable'
updated_at = <Date 2009-07-19.02:29:25.450>
user = 'https://github.com/phdru'

bugs.python.org fields:

activity = <Date 2009-07-19.02:29:25.450>
actor = 'r.david.murray'
assignee = 'r.david.murray'
closed = True
closed_date = <Date 2009-07-19.02:29:25.451>
closer = 'r.david.murray'
components = ['Interpreter Core']
creation = <Date 2009-05-20.10:58:48.034>
creator = 'phd'
dependencies = []
files = ['14072', '14337']
hgrepos = []
issue_num = 6070
keywords = ['patch']
message_count = 26.0
messages = ['88112', '88208', '88211', '88216', '88260', '88279', '88281', '88321', '88325', '88337', '89602', '89603', '89604', '89615', '89624', '89727', '89729', '89730', '89731', '89732', '89733', '90208', '90221', '90222', '90223', '90699']
nosy_count = 8.0
nosy_names = ['loewis', 'brett.cannon', 'georg.brandl', 'phd', 'tim.golden', 'r.david.murray', 'joe.amenta', 'markon']
pr_nums = []
priority = 'low'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue6070'
versions = ['Python 2.6', 'Python 3.1', 'Python 2.7', 'Python 3.2']

[phdru]

On compilation of .pyc/.pyo bytecode files on import Python 2.6 copies
Unix file access attributes (-rwx-) from the imported file. I'd think
it's ok except for executable (-x-) bit - bytecode files are not
directly executable. That is, for a module.py with attributes -rwxr-x---
I expect python2.6 -c 'import module' would produce module.pyc with
attributes -rw-r-----.

python compileall.py . saves compiled files without the executable bit;
it doesn't copy attributes - it just saves files and saving obeys umask.
python2.5 -c 'import module.py' doesn't copy the executable bit, it
obeys umask too. I consider this as a regression in 2.6. Please mask out
executable bits on bytecode files saving.

[loewis]

Would you like to provide a patch?

[joeamenta]

Python writes compiled files with the same file permissions as the
source module. In your specific example:

$ python2.6 -c 'import module'

This will produce module.pyc with the same attributes as module.py

While I am not familiar with modifying C stat structs, I can say that in
trunk/Python/import.c, somewhere after line 977 but before line 1014,
the stat struct "st" must be examined for S_IXUSR, S_IXGRP, and S_IXOTH
and have those bits removed in order to never produce a compiled module
with "x" in the stat. I would assign low priority to this issue, as it
has little impact on the behavior of Python, even though it might cause
unintended consequences to a user trying to execute the bytecode, if the
user interprets the "x" to mean that it is executable by the system.

[phdru]

I will try to look at import.c, though I must say I am a bad C
programmer. I have switched to Python after ten years of Pascal.

Low priority is ok.

[markon]

I attach a patch to correct this little bug.

Bye ;)

[birkenfeld]

Are these S_IX... constants available on every platform we support?

[loewis]

No, they are not supported on Visual Studio.

[markon]

TO georg.brandl:
I remembered that Windows wasn't POSIX compliant, but...I thought they
used the same sys/stat.h constants.
I was wrong :P

TO loewis:
ok, I've added a new patch.
Since I've never written any code for Windows, can you check if it works
fine now?
I've added a simple #ifdef WINDOWS,...

[loewis]

The patch of file 14070 doesn't compile, but I get the idea. I won't
have time to test it in the next few days or weeks, though.

[markon]

TO loewis:
this new patch works fine.
I've removed the first #endif.

thank you ;)

[phdru]

import_patch2.patch doesn't work for me. I patched and compiled Python
2.6.2 and without installing it ran ./python -c "import test" in the
build directory. It copied executable bits from test.py to test.pyc.

[markon]

hmm.. the problem is that Windows doesn't support well permissions as
all the other POSIX compliant OSs ...
I've searched for a solution on the web, and I've found a complete
answer on:
http://stackoverflow.com/questions/592448/c-how-to-set-file-permissions-cross-platform

The patch doesn't work well since it only checks for User's permissions
so it works well for that.
Maybe using the Windows API you can change the permissions as you want.
But since I don't know them, I can't help anymore :(