Re: [pypy-dev] [pypy-svn] r45269 - in pypy/dist/pypy/rpython/module: . tes
Hello again,
I think the error comes from the ctypes interpretation of the structure. utsname is not made of char* pointers, but (at least on the debian machine I have access to) the members are actually fixed arrays of chars, the lengths of which are not public, but well specified in sys/utsname.h. It should make no difference when translated, because the code looks like v->sysname etc. ctypes on the other hand needs to know the precise sizeof and offsets of each member. I tried to modify the _socket module to also use rffi, and had the same problem. I think that we will need a tool similar to pypy.rpython.rctypes.tool.ctypes_platform, which generates and compiles C code to get the different sizes and offsets. (We will need support for C defines as well) Hope this helps, -- Amaury Forgeot d'Arc
From the manpage: The length of the arrays in a struct utsname is unspecified; the fields are terminated by a null byte (’’ ’). ??? I'm completely confused. :.
Hi Fijal, On Mon, Jul 23, 2007 at 02:38:32PM +0200, Maciek Fijalkowski wrote:
It means that the structure looks like this in lltype notation: Struct('utsname', ('text1', FixedSizeArray(Char, 10)), ('text2', FixedSizeArray(Char, 20)), ...) where, annoyingly, the numbers '10' and '20' are platform-dependent and must be obtained by trying to compile snippets of C code using sizeof() and offsetof(). Or are you confused about the bit saying that the fields are zero-terminated? It just means that in the array, characters 0 to N-1 are non-null, charater N is null, and the rest of the characters are undefined. A bientot, Armin.
On 24.07.2007, at 18:08, Armin Rigo wrote:
Which reminds us to implement this carefully and not to rely on the terminating byte, or we will open the door to buffer overflow exploits :-) ciao - chris -- Christian Tismer :^) <mailto:tismer@stackless.com> tismerysoft GmbH : Have a break! Take a ride on Python's Johannes-Niemeyer-Weg 9A : *Starship* http://starship.python.net/ 14109 Berlin : PGP key -> http://wwwkeys.pgp.net/ work +49 30 802 86 56 mobile +49 173 24 18 776 fax +49 30 80 90 57 05 PGP 0x57F3BF04 9064 F4E1 D754 C2FF 1619 305B C09C 5A3B 57F3 BF04 whom do you want to sponsor today? http://www.stackless.com/
From the manpage: The length of the arrays in a struct utsname is unspecified; the fields are terminated by a null byte (’’ ’). ??? I'm completely confused. :.
Hi Fijal, On Mon, Jul 23, 2007 at 02:38:32PM +0200, Maciek Fijalkowski wrote:
It means that the structure looks like this in lltype notation: Struct('utsname', ('text1', FixedSizeArray(Char, 10)), ('text2', FixedSizeArray(Char, 20)), ...) where, annoyingly, the numbers '10' and '20' are platform-dependent and must be obtained by trying to compile snippets of C code using sizeof() and offsetof(). Or are you confused about the bit saying that the fields are zero-terminated? It just means that in the array, characters 0 to N-1 are non-null, charater N is null, and the rest of the characters are undefined. A bientot, Armin.
On 24.07.2007, at 18:08, Armin Rigo wrote:
Which reminds us to implement this carefully and not to rely on the terminating byte, or we will open the door to buffer overflow exploits :-) ciao - chris -- Christian Tismer :^) <mailto:tismer@stackless.com> tismerysoft GmbH : Have a break! Take a ride on Python's Johannes-Niemeyer-Weg 9A : *Starship* http://starship.python.net/ 14109 Berlin : PGP key -> http://wwwkeys.pgp.net/ work +49 30 802 86 56 mobile +49 173 24 18 776 fax +49 30 80 90 57 05 PGP 0x57F3BF04 9064 F4E1 D754 C2FF 1619 305B C09C 5A3B 57F3 BF04 whom do you want to sponsor today? http://www.stackless.com/
participants (4)
-
Amaury Forgeot d'Arc -
Armin Rigo -
Christian Tismer -
Maciek Fijalkowski