Re: [patch] Do not open Python scripts twice #2 [Re: [RFC] Crash sourcing Python script on Windows]

[Doug Evans <dje at google dot com>]

On Mon, Jan 23, 2012 at 1:08 PM, Jan Kratochvil
<jan.kratochvil@redhat.com> wrote:
> On Mon, 23 Jan 2012 19:38:34 +0100, Pedro Alves wrote:
>> > +# MS-Windows platform may have Python compiled with different libc
>> > +# having the FILE structure layout incompatible between libraries.
>>
>> It is not just about the layout. ?The layout of both libc's could be the
>> same, but you'd still (maybe) crash. ?It's more about the private global
>> state maintained by each of the libc's. ?E.g., file descriptor N of
>> gdb's libc has no meaning the python's libc -- each libc has its own
>> file descriptor table.
>
> I have updated the text.
>
>
>> This is undefined behavior in the supposedly crashing case. ?Hopefully this
>> doesn't happen to succeed by running some other random program. ?:-)
>
> Yes, my fear is that if for example the only problem is fd assignments it may
> try to read from a closed descriptor possibly behaving as empty file and it
> would falsely pass. ?Better test would be it did really read some test Python
> code but a minimal such testcase looks pretty complicated to me for configure.
> But when Joel was talking about "crash" this simple test may be enough.
>
>
>> The patch looks good to me.
>
> These are the reasons why I would prefer a real MS-Windows test of it.
>
>
> Thanks,
> Jan
>
>
> gdb/
> 2012-01-23 ?Jan Kratochvil ?<jan.kratochvil@redhat.com>
>
> ? ? ? ?Do not open script filenames twice.
> ? ? ? ?* cli/cli-cmds.c (source_script_from_stream): Pass to
> ? ? ? ?source_python_script also STREAM.
> ? ? ? ?* config.in: Regenerate.
> ? ? ? ?* configure: Regenerate.
> ? ? ? ?* configure.ac (HAVE_PYTHON_FILEP_COMPAT): New test.
> ? ? ? ?* python/py-auto-load.c (source_section_scripts): Pass to
> ? ? ? ?source_python_script_for_objfile also STREAM.
> ? ? ? ?(auto_load_objfile_script): Pass to source_python_script_for_objfile
> ? ? ? ?also INPUT.
> ? ? ? ?* python/python-internal.h (source_python_script_for_objfile): New
> ? ? ? ?parameter file, rename parameter file to filename.
> ? ? ? ?* python/python.c (python_run_simple_file): Call PyRun_SimpleFile
> ? ? ? ?instead if HAVE_PYTHON_FILEP_COMPAT.
> ? ? ? ?(source_python_script, source_python_script_for_objfile)
> ? ? ? ?(source_python_script): New parameter file, rename parameter file to
> ? ? ? ?filename. ?Pass FILENAME to python_run_simple_file.
> ? ? ? ?* python/python.h (source_python_script): New parameter file, rename
> ? ? ? ?parameter file to filename.

Hi.
Do you have any data that shows there is a problem with the double opening?
[I'm kinda uncomfortable with this patch, as is.]