Message370105
| Author |
vstinner |
| Recipients |
amaury.forgeotdarc, belopolsky, furkanonder, meador.inge, miss-islington, python-dev, vstinner |
| Date |
2020-05-27.15:54:46 |
| SpamBayes Score |
-1.0 |
| Marked as misclassified |
Yes |
| Message-id |
<1590594886.31.0.286700595551.issue13097@roundup.psfhosted.org> |
| In-reply-to |
|
| Content |
Thanks Meador Inge for the bug report and thanks Sean Gillespie for the fix! It just took 9 years to fix this corner case ;-)
Copy of the comment on the PR:
https://github.com/python/cpython/pull/19914#pullrequestreview-419331432
I tried to rewrite _ctypes_callproc() to use PyMem_Malloc() instead of alloca(), but it's quite complicated. There are 3 arrays with a length of argcount items: args, avalues, atypes. Moreover, resbuf is also allocated with alloca(). When using PyMem_Malloc(), error handling is much more complicated.
I also tried to restrict the overall usage of stack memory to 4096 bytes (size of one page on x86), but users would be surprised by CTYPES_MAX_ARGCOUNT value.
I would say that raising an exception is better than crashing for a lot of arguments. If someone is blocked by this new limitation, in that case we can revisit the PyMem_Malloc() idea. |
|