From 562b852514534b05882a67ed6dafb98868c650de Mon Sep 17 00:00:00 2001
From: Justin Lebar <justin.lebar@gmail.com>
Date: Fri, 18 Jan 2013 16:34:22 -0500
Subject: [PATCH 1/2] Add a |python| wrapper script which sets the right
 environment variables and invokes /data/python/bin/python.

Crucially, the wrapper script sets LD_PRELOAD=libpython2.7.so.  Without
this, we can't load any of the libs in lib-dynload, which means that we
can't import any Python module which uses native code (e.g. the select
module).

Without LD_PRELOAD, we get an error like the following when we try to
import a module which uses native code:

  >>> import subprocess
  Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/data/python/lib/python2.7/subprocess.py", line 429, in <module>
    import select
  ImportError: Cannot load library: reloc_library[1285]:  9814 cannot locate 'PyDict_Next'...

The root problem is that the lib-dynload libraries do not have an
explicit dependency on libpython.so (see readelf -d), so therefore the
bionic linker doesn't try to resolve their symbols against libpython.
Setting this dependency would be the Right Fix.
---
 README.md | 12 ++++--------
 python    |  6 ++++++
 2 files changed, 10 insertions(+), 8 deletions(-)
 create mode 100755 python

diff --git a/README.md b/README.md
index 340fb39..bf156f0 100644
--- a/README.md
+++ b/README.md
@@ -33,19 +33,15 @@ If your build was succesful then you can install Python using the `adb` tool, wh
 
 ```
 $ adb push install/data/python /data/python
+$ adb push python /system/bin/python
+$ adb shell chmod 766 /system/bin/python
 ```
 
-Using
-=====
-
-Once you have copied Python to your device you have to set `LD_LIBRARY_PATH`, `PYTHONHOME` and `PATH` correctly:
+Now you should be able to run python with
 
 ```
 $ adb shell
-root@android:/data # export LD_LIBRARY_PATH=/data/python/lib                   
-root@android:/data # export PYTHONHOME=/data/python
-root@android:/data # export PATH=$PATH:/data/python/bin
-root@android:/data # python
+# python
 Python 2.7.3 (default, Dec 20 2012, 14:25:30) 
 [GCC 4.4.3] on linux2
 Type "help", "copyright", "credits" or "license" for more information.
diff --git a/python b/python
new file mode 100755
index 0000000..0ddb3e7
--- /dev/null
+++ b/python
@@ -0,0 +1,6 @@
+#!/system/bin/sh
+
+export LD_LIBRARY_PATH=/data/python/lib
+export LD_PRELOAD=/data/python/lib/libpython2.7.so
+export PYTHONHOME=/data/python
+/data/python/bin/python $@

From 984536cb77bd6eb904a9061e691ca478a2f94bbd Mon Sep 17 00:00:00 2001
From: Justin Lebar <justin.lebar@gmail.com>
Date: Fri, 18 Jan 2013 16:55:22 -0500
Subject: [PATCH 2/2] Don't nuke the LD_LIBRARY_PATH and LD_PRELOAD variables.

You might want to pass an LD_LIBRARY_PATH to a child process of python, for example.
---
 python | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/python b/python
index 0ddb3e7..949f7bd 100755
--- a/python
+++ b/python
@@ -1,6 +1,6 @@
 #!/system/bin/sh
 
-export LD_LIBRARY_PATH=/data/python/lib
-export LD_PRELOAD=/data/python/lib/libpython2.7.so
+export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/data/python/lib
+export LD_PRELOAD=$LD_PRELOAD:/data/python/lib/libpython2.7.so
 export PYTHONHOME=/data/python
 /data/python/bin/python $@