This is a port of Python 2.6 to OS/2 using the EMX development tools
=========================================================================
What's new since the previous release
-------------------------------------
Another day, another version...
Licenses and info about Python and EMX
--------------------------------------
Please read the file README.Python-2.6 included in this package for
information about Python 2.6. This file is the README file from the
Python 2.6 source distribution available via http://www.python.org/
and its mirrors. The file LICENCE.Python-2.6 is the text of the Licence
from the Python 2.6 source distribution.
Note that the EMX package that this package depends on is released under
the GNU General Public Licence. Please refer to the documentation
accompanying the EMX Runtime libraries for more information about the
implications of this. A copy of version 2 of the GPL is included as the
file COPYING.gpl2.
Readline and GDBM are covered by the GNU General Public Licence. I think
Eberhard Mattes' porting changes to BSD DB v1.85 are also GPL'ed (BSD DB
itself is BSD Licenced). ncurses and expat appear to be covered by MIT
style licences - please refer to the source distributions for more detail.
zlib is distributable under a very free license. GNU UFC is under the
GNU LGPL (see file COPYING.lib).
My patches to the Python-2.x source distributions, and any other packages
used in this port, are placed in the public domain.
This software is provided 'as-is', without any express or implied warranty.
In no event will the author be held liable for any damages arising from the
use of the software.
I do hope however that it proves useful to someone.
Other ports
-----------
There have been ports of previous versions of Python to OS/2.
The best known would be that by Jeff Rush, most recently of version
1.5.2. Jeff used IBM's Visual Age C++ (v3) for his ports, and his
patches have been included in the Python 2.6 source distribution.
Andy Zabolotny implemented a port of Python v1.5.2 using the EMX
development tools. His patches against the Python v1.5.2 source
distribution have become the core of this port, and without his efforts
this port wouldn't exist. Andy's port also appears to have been
compiled with his port of gcc 2.95.2 to EMX, which I have but have
chosen not to use for the binary distribution of this port (see item 16
of the "YOU HAVE BEEN WARNED" section below).
It is possible to have these earlier ports still usable after installing
this port - see the README.os2emx.multiple_versions file, contributed by
Dr David Mertz, for a suggested approach to achieving this.
Software requirements
---------------------
This package requires the EMX Runtime package, available from the
Hobbes (http://hobbes.nmsu.edu/) and LEO (http://archiv.leo.org/)
archives of OS/2 software. I have used EMX version 0.9d fix04 in
developing this port.
My development system is running OS/2 v4 with fixpack 12.
3rd party software which has been linked into dynamically loaded modules:
- ncurses (see http://dickey.his.com/ for more info, v5.2)
- GNU Readline (Kai Uwe Rommel's port available from Hobbes or LEO, v2.1)
- GNU GDBM (Kai Uwe Rommel's port available from Hobbes or LEO, v1.7.3)
- zlib (derived from Hung-Chi Chu's port of v1.1.3, v1.1.4)
- expat (distributed with Python, v1.95.6)
- GNU UFC (Kai Uwe Rommel's port available from LEO, v2.0.4)
About this port
---------------
I have attempted to make this port as complete and functional as I can,
notwithstanding the issues in the "YOU HAVE BEEN WARNED" section below.
Core components:
Python.exe is linked as an a.out executable, ie using EMX method E1
to compile & link the executable. This is so that fork() works (see
"YOU HAVE BEEN WARNED" item 1).
Python26.dll is created as a normal OMF DLL, with an OMF import
library and module definition file. There is also an a.out (.a) import
library to support linking the DLL to a.out executables. The DLL
requires the EMX runtime DLLs.
This port has been built with complete support for multithreading.
Modules:
With the exception of modules that have a significant code size, or are
not recommended or desired for normal use, the standard modules are now
built into the core DLL rather than configured as dynamically loadable
modules. This is for both reasons of performance (startup time) and
memory use (lots of small DLLs fragment the address space).
I haven't yet changed the building of Python's dynamically loadable
modules over to using the DistUtils.
See "YOU HAVE BEEN WARNED" item 3 for notes about the fcntl module, and
"YOU HAVE BEEN WARNED" item 10 for notes about the pwd and grp modules.
This port supports case sensitive module import semantics, matching
the Windows release. This can be deactivated by setting the PYTHONCASEOK
environment variable (the value doesn't matter) - see "YOU HAVE BEEN WARNED"
item 12.
Optional modules:
Where I've been able to locate the required 3rd party packages already
ported to OS/2, I've built and included them.
These include ncurses (_curses, _curses_panel),
GNU GDBM (gdbm, dbm), zlib (zlib), GNU Readline (readline), and GNU UFC
(crypt).
Expat is now included in the Python release sourceball, and the pyexpat
module is always built.
I have built these modules statically linked against the 3rd party
libraries. Unfortunately my attempts to use the dll version of GNU
readline have been a dismal failure, in that when the dynamically
linked readline module is active other modules immediately provoke a
core dump when imported.
Only the BSD DB package (part of the BSD package distributed with EMX)
needs source modifications to be used for this port, pertaining to use
of errno with multithreading.
The other packages, except for ncurses and zlib, needed Makefile changes
for multithreading support but no source changes.
The _curses_panel module is a potential problem - see "YOU HAVE BEEN
WARNED" item 13.
Upstream source patches:
No updates to the Python 2.6 release have become available.
Library and other distributed Python code:
The Python standard library lives in the Lib directory. All the standard
library code included with the Python 2.6 source distribution is included
in the binary archive, with the exception of the dos-8x3 and tkinter
subdirectories which have been omitted to reduce the size of the binary
archive - the dos-8x3 components are unnecessary duplicates and Tkinter
is not supported by this port (yet). All the plat-* subdirectories in the
source distribution have also been omitted, except for the plat-os2emx
subdirectory.
The Tools and Demo directories contain a collection of Python scripts.
To reduce the size of the binary archive, the Demo/sgi, Demo/Tix,
Demo/tkinter, Tools/audiopy and Tools/IDLE subdirectories have been
omitted as not being supported by this port. The Misc directory has
also been omitted.
All subdirectories omitted from the binary archive can be reconstituted
from the Python 2.6 source distribution, if desired.
Support for building Python extensions:
The Config subdirectory contains the files describing the configuration
of the interpreter and the Makefile, import libraries for the Python DLL,
and the module definition file used to create the Python DLL. The
Include subdirectory contains all the standard Python header files
needed for building extensions.
As I don't have the Visual Age C++ compiler, I've made no attempt to
have this port support extensions built with that compiler.
Packaging
---------
This port is packaged as follows:
- python-2.6-os2emx-bin-03????.zip (binaries, library modules)
- python-2.6-os2emx-src-03???? (patches+makefiles for non-Python code)
As all the Python specific patches for the port are now part of the
Python release tarball, only the patches and makefiles involved in
building external libraries for optional extensions are included in
the source archive.
Documentation for the Python language, as well as the Python 2.6
source distibution, can be obtained from the Python website
(http://www.python.org/) or the Python project pages at Sourceforge
(http://sf.net/projects/python/).
Installation
------------
Obtain and install, as per the included instructions, the EMX runtime
package.
Unpack this archive, preserving the subdirectories, in the root directory
of the drive where you want Python to live.
Add the Python directory (eg C:\Python26) to the PATH and LIBPATH
variables in CONFIG.SYS.
You should then set the PYTHONHOME and PYTHONPATH environment variables
in CONFIG.SYS.
PYTHONHOME should be set to Python's top level directory. PYTHONPATH
should be set to the semicolon separated list of principal Python library
directories.
I use:
SET PYTHONHOME=F:/Python26
SET PYTHONPATH=F:/Python26/Lib;F:/Python26/Lib/plat-os2emx;
F:/Python26/Lib/lib-dynload;F:/Python26/Lib/site-packages
NOTE!: the PYTHONPATH setting above is linewrapped for this document - it
should all be on one line in CONFIG.SYS!
If you wish to use the curses module, you should set the TERM and TERMINFO
environment variables appropriately.
If you don't already have ncurses installed, I have included a copy of the
EMX subset of the Terminfo database included with the ncurses-5.2 source
distribution. This can be used by setting the TERMINFO environment variable
to the path of the Terminfo subdirectory below the Python home directory.
On my system this looks like:
SET TERMINFO=F:/Python26/Terminfo
For the TERM environment variable, I would try one of the following:
SET TERM=ansi
SET TERM=os2
SET TERM=window
You will have to reboot your system for these changes to CONFIG.SYS to take
effect.
If you wish to compile all the included Python library modules to bytecode,
you can change into the Python home directory and run the COMPILEALL.CMD
batch file.
You can execute the regression tests included with the Python 2.6 source
distribution by changing to the Python 2.6 home directory and executing the
REGRTEST.CMD batch file. The following tests are known to fail at this
time:
- test_mhlib (I don't know of any port of MH to OS/2);
- test_strptime (see "YOU HAVE BEEN WARNED" item 22);
- test_time (see "YOU HAVE BEEN WARNED" item 22);
- test_posixpath (see "YOU HAVE BEEN WARNED" item 23).
Note that some of the network related tests expect the loopback interface
(interface "lo", with IP address 127.0.0.1) to be enabled, which from my
experience is not the default configuration. Additionally, test_popen2
expects the "cat" utility (such as found in ports of the GNU tools) to
be installed.
Building from source
--------------------
With the EMX port now checked into Python's CVS repository, the build
infrastructure is part of the Python release sourceball.
Prerequisites
First and foremost, you need an operational EMX development installation -
EMX v0.9d with fix04 (the latest at time of writing) & the gcc 2.8.1
compiler released by Eberhard Mattes is the recommended setup.
If you have a different version of gcc installed, see "YOU HAVE BEEN
WARNED" item 16.
Other items of software required:-
- GNU make (I'm using v3.76.1)
- rm, cp, mkdir from the GNU file utilities package
- GNU find
- GNU sed
Procedure
0. all changes mentioned apply to files in the PC/os2emx subdirectory
of the Python release source tree. make is also executed from this
directory, so change into this directory before proceeding.
1. decide if you need to change the location of the Python installation.
If you wish to do this, set the value of the Makefile variable LIB_DIR
to the directory you wish to use for PYTHONHOME
(eg /usr/local/lib/python2.6).
If you want Python to find its library without the PYTHONHOME
environment variable set, set the value of the Makefile variable
FIXED_PYHOME to "yes" (uncomment the appropriate line).
2. If you wish the Python executables (python.exe, pythonpm.exe & pgen.exe)
to be installed in a directory other than the PYTHONHOME directory, set
the value of the Makefile variable EXE_DIR to the appropriate directory.
3. If you wish the Python core DLL (python26.dll) to be installed in a
directory other than the directory in which the Python executables are
installed (by default, the PYTHONHOME directory), set the value of the
Makefile variable DLL_DIR to the appropriate directory. This DLL must
be placed in a directory on the system's LIBPATH, or that gets set
with BEGINLIBPATH or ENDLIBPATH.
4. If you have installed any of the libraries that can be used to build
optional Python modules, set the value of the relevant HAVE_<package>
Makefile variable to "yes". The Makefile currently supports:
library Makefile variable
........................................
zlib (1.1.4) HAVE_ZLIB
GNU UltraFast Crypt HAVE_UFC
Tcl/Tk HAVE_TCLTK (not known to work)
GNU Readline HAVE_GREADLINE
ncurses HAVE_NCURSES
GNU gdbm HAVE_GDBM
libbz2 HAVE_BZ2
OpenSSL HAVE_OPENSSL
Please note that you need to check that what you have installed
is compatible with Python's build options. In particular, the
BSD DB v1.85 library needs to be rebuilt with a source patch for
multithread support (doesn't change the library's reentrant status
but allows it to be linked to Python which is multithreaded).
Widely available binary packages of other librarys & DLLs are
not built/linked with multithread support. Beware!
Also note that the Makefile currently expects any libraries to be
found with the default library search path. You may need to add
-L switches to the LDFLAGS Makefile variable if you have installed
libraries in directories not in the default search path (which can
be controlled by the LIBRARY_PATH environment variable used by EMX).
5. make
It is usually a good idea to redirect the stdout and stderr streams
of the make process to log files, so that you can review any messages.
6. make test
This runs the Python regression tests, and completion is a sign of
a usable build. You should check the list of skipped modules to
ensure that any optional modules you selected have been built;
checking the list of failures against the list of known failures
elsewhere in this document is also prudent.
7. make install
>>>>>> NOT YET COMPLETE <<<<<<
8. change to a directory outside the Python source tree and start Python.
Check the version and build date to confirm satisfactory installation.
YOU HAVE BEEN WARNED!!
----------------------
I know about a number of nasties in this port.
1. Eberhard Mattes, author of EMX, writes in his documentation that fork()
is very inefficient in the OS/2 environment. It also requires that the
executable be linked in a.out format rather than OMF. Use the os.exec
and/or the os.spawn family of functions where possible.
2. In the absence of GNU Readline, terminating the interpreter requires a
control-Z (^Z) followed by a carriage return. Jeff Rush documented this
problem in his Python 1.5.2 port. With Readline, a control-D (^D) works
as per the standard Unix environment.
3. EMX only has a partial implementation of fcntl(). The fcntl module
in this port supports what EMX supports. If fcntl is important to you,
please review the EMX C Library Reference (included in .INF format in the
EMXVIEW.ZIP archive as part of the complete EMX development tools suite).
Because of other side-effects I have modified the test_fcntl.py test
script to deactivate the exercising of the missing functionality.
4. The readline module has been linked against ncurses rather than the
termcap library supplied with EMX.
5. I have configured this port to use "/" as the preferred path separator
character, rather than "\" ('\\'), in line with the convention supported
by EMX. Backslashes are still supported of course, and still appear in
unexpected places due to outside sources that don't get normalised.
6. While the DistUtils components are now functional, other
packaging/binary handling tools and utilities such as those included in
the Demo and Tools directories - freeze in particular - are unlikely to
work. If you do get them going, I'd like to know about your success.
7. I haven't set out to support the [BEGIN|END]LIBPATH functionality
supported by one of the earlier ports (Rush's??). If it works let me know.
8. As a result of the limitations imposed by EMX's library routines, the
standard extension module pwd only synthesises a simple passwd database,
and the grp module cannot be supported at all.
I have written pure Python substitutes for pwd and grp, which can process
real passwd and group files for those applications (such as MailMan) that
require more than EMX emulates. I have placed pwd.py and grp.py in
Lib/plat-os2emx, which is usually before Lib/lib-dynload (which contains
pwd.pyd) in the PYTHONPATH. If you have become attached to what pwd.pyd
supports, you can put Lib/lib-dynload before Lib/plat-os2emx in PYTHONPATH
or delete/rename pwd.py & grp.py.
pwd.py & grp.py support locating their data files by looking in the
environment for them in the following sequence:
pwd.py: $ETC_PASSWD (%ETC_PASSWD%)
$ETC/passwd (%ETC%/passwd)
$PYTHONHOME/Etc/passwd (%PYTHONHOME%/Etc/passwd)
grp.py: $ETC_GROUP (%ETC_GROUP%)
$ETC/group (%ETC%/group)
$PYTHONHOME/Etc/group (%PYTHONHOME%/Etc/group)
The ETC_PASSWD and ETC_GROUP environment variables are intended to allow
support for multiple passwd/grp files, where other applications may not
support as wide a variety of input variations (drive remappings,
separators etc).
Both modules support using either the ":" character (Unix standard) or
";" (OS/2, DOS, Windows standard) field separator character, and pwd.py
implements the following drive letter conversions for the home_directory and
shell fields (for the ":" separator only):
$x -> x:
x; -> x:
Example versions of passwd and group are in the Etc subdirectory. The
regression tests (test_pwd and test_grp) will fail if valid password and
group files cannot be found, but should pass otherwise.
Be aware that Python's pwd & group modules are for reading password and
group information only.
11. EMX's termios routines don't support all of the functionality now
exposed by the termios module - refer to the EMX documentation to find
out what is supported.
12. The case sensitive import semantics introduced in Python 2.1 for other
case insensitive but case preserving file/operating systems (Windows etc),
have been incorporated into this port, and are active by default. Setting
the PYTHONCASEOK environment variable (to any value) reverts to the
previous (case insensitive) semantics. This can be an issue with some
file management utilities that do not preserve the case of file and
directory names.
13. Because I am statically linking ncurses, the _curses_panel
module has potential problems arising from separate library data areas.
To avoid this, I have configured the _curses_.pyd (imported as
"_curses_panel") to import the ncurses symbols it needs from _curses.dll
(which is the curses module, but with a .dll extension rather than .pyd
so that the dynamic loader can actually import the symbols from it as a
DLL).
The site module (Lib/site.py) has code added to tweak BEGINLIBPATH so
that _curses.dll is found when _curses_panel is imported. If you have
problems attempting to use the _curses_panel support please let me know,
and I'll have another look at this.
14. sys.platform reports "os2emx" instead of "os2". os.name still
reports "os2". This change was to make it easier to distinguish between
the VAC++ build (formerly maintained by Michael Muller) and the EMX build
(this port), principally for DistUtils.
15. it appears that the %W substitution in the EMX strftime() routine has
an off-by-one bug. strftime was listed as passing the regression tests
in previous releases, but this fact appears to have been an oversight in
the regression test suite. To fix this really requires a portable
strftime routine - I'm looking into using one from FreeBSD, but its not
ready yet.
16. I have successfully built this port with Andy Zabolotny's ports of
pgcc 2.95 and gcc 3.2.1, in addition to EM's gcc 2.8.1.
I have not attempted to compile Python with any version of gcc prior to
v2.8.1.
This release sees the default optimisation change to
"-O3 -fomit-frame-pointer -mprobe". This works fine too for pgcc 2.95
but not for gcc 3.2.1.
With gcc 3.2.1, -O3 causes 2 unexpected test failures: test_format and
test_unicode. Both these tests pass if -O2 is instead of -O3 with this
compiler, and the performance difference is negligible (in contrast to
gcc 2.8.1 and pgcc 2.95, where the performance difference between the
2 optimisation settings approaches 10%).
17. os.spawnv() and os.spawnve() expose EMX's library routines rather
than use the emulation in os.py.
In order to make use of some of the features this makes available in
the OS/2 environment, you should peruse the relevant EMX documentation
(EMXLIB.INF in the EMXVIEW.ZIP archive accompanying the EMX archives
on Hobbes or LEO). Be aware that I have exposed all the "mode" options
supported by EMX, but there are combinations that either cannot be
practically used by/in Python or have the potential to compromise your
system's stability.
18. pythonpm.exe used to be just python.exe with the WINDOWAPI linker
option set in the pythonpm.def file. In practice, this turns out to do
nothing useful.
I have written a replacement which wraps the Python DLL in a genuine
Presentation Manager application. This version actually runs the
Python interpreter in a separate thread from the PM shell, in order
that PythonPM has a functioning message queue as good PM apps should.
In its current state, PythonPM's window is hidden. It can be displayed,
although it will have no content as nothing is ever written to the
window. Only the "hide" button is available. Although the code
has support for shutting PythonPM down when the Python interpreter is
still busy (via the "control" menu), this is not well tested and given
comments I've come across in EMX documentation suggesting that the
thread killing operation has problems I would suggest caution in
relying on this capability.
PythonPM processes commandline parameters normally. The standard input,
output and error streams are only useful if redirected, as PythonPM's
window is not a console in any form and so cannot accept or display
anything. This means that the -i option is ineffective.
Because the Python thread doesn't create its own message queue, creating
PM Windows and performing most PM operations is not possible from within
this thread. How this will affect supporting PM extensions (such as
Tkinter using a PM port of Tcl/Tk, or wxPython using the PM port of
WxWindows) is still being researched.
Note that os.fork() _DOES_NOT_WORK_ in PythonPM - SYS3175s are the result
of trying. os.spawnv() _does_ work. PythonPM passes all regression tests
that the standard Python interpreter (python.exe) passes, with the exception
of test_fork1 and test_socket which both attempt to use os.fork().
I very much want feedback on the performance, behaviour and utility of
PythonPM. I would like to add a PM console capability to it, but that
will be a non-trivial effort. I may be able to leverage the code in
Illya Vaes' Tcl/Tk port, which would make it easier.
19. os.chdir() uses EMX's _chdir2(), which supports changing both drive
and directory at once. Similarly, os.getcwd() uses EMX's _getcwd()
which returns drive as well as path.
20. pyconfig.h is installed in the Include subdirectory with all
other include files.
21. the default build explicitly sets the number of file handles
available to a Python process to 250. EMX default is 40, which is
insufficient for the tempfile regression test (test_tempfile) which
tries to create 100 temporary files.
This setting can be overridden via the EMXOPT environment variable:
set EMXOPT=-h250
is equivalent to the setting currently used. The emxbind utility (if you
have it installed) can also be used to permanently change the setting in
python.exe - please refer to the EMX documentation for more information.
22. a pure python strptime module is now part of the Python standard
library, superceding a platform specific extension module. This module
leverages the strftime module, and as a result test_strptime fails
due to the EMX strftime bug in item 20 above.
23. test_posixpath attempts to exercise various Posix path related
functionality. Most of the sub-tests pass, but the "ismount" and
"samestat" subtests fail:
- EMX provides not satisfactory mount point emulation, so "ismount"
cannot succeed;
- EMX documents that successive stat() calls will produce different
results, so "samestat" cannot succeed.
test_posixpath should skip these tests on EMX.
24. I have reports of BitTorrent not working. It appears that the
EMX select() emulation, possibly in concert with bugs in the TCP/IP
stack, runs into problems under the stress imposed by this application.
I think it suffices to say that BitTorrent is a fair stress test of a
system's networking capability.
25. In the absence of an EMX implementation of the link() function, I've
implemented a crude Python emulation, in the file
Lib/plat-os2emx/_emx_link.py. This is imported into the os module, and
becomes available as os.link() in the normal way.
The emulation copies the source file in binary mode, and will fail if
disk space is exhausted. The call fails if the target already exists.
There are no guarantees to thread safety with this emulation - beware!
The emulation was written to support a link() based file locking system
used in GNU Mailman.
26. AF_UNIX sockets, otherwise known as Unix domain sockets, are now
supported. Unfortunately, there are some traps arising from the
implementation in IBM's TCP/IP stack:-
- the path name must start with '\\socket\\' ('/socket/' won't work!),
with the length of the full path name less than 108 characters;
- unlike Unix, the socket endpoints don't exist in the filesystem;
- by default, sockets are in binary mode.
27. As of Python 2.4, the mpz, rotor and xreadlines modules have been
dropped from the Python source tree.
28. The subprocess module was added to the standard library relatively
late in the 2.4 development cycle. Unfortunately I haven't had the
round tuits to adapt the module to the EMX environment yet, and
test_subprocess has a number of failures as a result.
29. The default stack size for threads has been 64k. This is proving
insufficient for some codebases, such as Zope. The thread stack size
still defaults to 64k, but this can now be increased via the stack_size()
function exposed by the threading & thread modules as well as by defining
THREAD_STACK_SIZE to an appropriate value in the Makefile (which contains
a commented out definition for 128kB thread stacks). I have seen
references to heavy Zope/Plone usage requiring 1MB thread stacks on
FreeBSD and Linux, but doubt that for most likely usage on OS/2 that
more than 256kB is necessary. The size of the required stacks (main
and thread) can vary significantly depending on which version of gcc
is used along with the compiler optimisations selected. Note that the
main thread stack size is set during linking and is currently 2MB.
... probably other issues that I've not encountered, or don't remember :-(
If you encounter other difficulties with this port, which can be
characterised as peculiar to this port rather than to the Python release,
I would like to hear about them. However I cannot promise to be able to do
anything to resolve such problems. See the Contact section below...
To do...
--------
In no particular order of apparent importance or likelihood...
- support Tkinter and/or alternative GUI (wxWindows??)
Credits
-------
In addition to people identified above, I'd like to thank:
- the BDFL, Guido van Rossum, and crew for Python;
- Dr David Mertz, for trying out a pre-release of this port;
- the Python-list/comp.lang.python community;
- John Poltorak, for input about pwd/grp.
Contact
-------
Constructive feedback, negative or positive, about this port is welcome
and should be addressed to me at the e-mail addresses below.
I have a private mailing list for announcements of fixes & updates to
this port. If you wish to receive such e-mail announcments, please send
me an e-mail requesting that you be added to this list.
Andrew MacIntyre
E-mail: andymac@bullseye.apana.org.au, or andymac@pcug.org.au
Web: http://www.andymac.org/
28 January, 2008.
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