It seems, no code actually uses these names, only sizes of the unnamed
union members are important. Though, I think it's good to be here
consistent wrt type codes ('g' for long double, etc).
This amends 85f89cb3e6.
Fix: Prevent crash in ctypes.CField when byte_size does not match type size (gh-132470)
When creating a ctypes.CField with an incorrect byte_size (e.g., using `byte_size=2` for `ctypes.c_byte`), the code would previously abort due to the failed assertion `byte_size == info->size`.
This commit replaces the assertion with a proper error handling mechanism that raises a `ValueError` when `byte_size` does not match the expected type size. This prevents the crash and provides a more informative error message to the us
Co-authored-by: sobolevn <mail@sobolevn.me>
Add extra audit hooks to catch C function calling from ctypes,
reading/writing files through readline and executing external
programs through _posixsubprocess.
* Make audit-tests for open pass when readline.append_history_file is unavailable
* Less direct testing of _posixsubprocess for audit hooks
* Also remove the audit hook from call_cdeclfunction now that _ctypes_callproc does it instead.
* reword the NEWS entry.
* mention readline in NEWS
* add versionchanged markers
* fix audit_events.rst versionadded
* doc lint
---------
Co-authored-by: Gregory P. Smith <greg@krypto.org>
- Restore max field size to sys.maxsize, as in Python 3.13 & below
- PyCField: Split out bit/byte sizes/offsets.
- Expose CField's size/offset data to Python code
- Add generic checks for all the test structs/unions, using the newly exposed attrs
* Visit keep in StructParam_traverse
* Decref swapped in PyCSimpleType_init
* Decref ob in make_funcptrtype_dict
* Check Pointer_item result while constructing result list in Pointer_subscript
* Fix align and size naming in PyCStructUnionType_update_stginfo
- as discussed in previous PR
Unlikely errors in preparing arguments for ctypes callback are now
handled in the same way as errors raised in the callback of in converting
the result of the callback -- using sys.unraisablehook() instead of
sys.excepthook() and not setting sys.last_exc and other variables.
This fixes UBSan failures for the following objects:
- `DictRemoverObject` and `StructParamObject`,
- `CDataObject` and `CFieldObject`, and
- `PyCFuncPtrObject` and `PyCArgObject`.
On the default build, we convert the `LOCK_PTR` and `UNLOCK_PTR` macros to
functions with an unused parameter to ease "unused variable" compiler warnings
suppression. Finally, we also remove some redundant casts to `PyObject *`.
This should be a pure refactoring, without user-visible behaviour changes.
Before this change, ctypes uses traditional native C types, usually identified
by [`struct` format characters][struct-chars] when a short (and
identifier-friendly) name is needed:
- `signed char` (`b`) / `unsigned char` (`B`)
- `short` (`h`) / `unsigned short` (`h`)
- `int` (`i`) / `unsigned int` (`i`)
- `long` (`l`) / `unsigned long` (`l`)
- `long long` (`q`) / `unsigned long long` (`q`)
These map to C99 fixed-width types, which this PR switches to: -
- `int8_t`/`uint8_t`
- `int16_t`/`uint16_t`
- `int32_t`/`uint32_t`
- `int64_t`/`uint64_t`
The C standard doesn't guarantee that the “traditional” types must map to the
fixints. But, [`ctypes` currently requires it][swapdefs], so the assumption won't
break anything.
By “map” I mean that the *size* of the types matches. The *alignment*
requirements might not. This needs to be kept in mind but is not an issue in
`ctypes` accessors, which [explicitly handle unaligned memory][memcpy] for the
integer types.
Note that there are 5 “traditional” C type sizes, but 4 fixed-width ones. Two of
the former are functionally identical to one another; which ones they are is
platform-specific (e.g. `int`==`long`==`int32_t`.) This means that one of the
[current][current-impls-1] [implementations][current-impls-2] is redundant on
any given platform.
The fixint types are parametrized by the number of bytes/bits, and one bit for
signedness. This makes it easier to autogenerate code for them or to write
generic macros (though generic API like
[`PyLong_AsNativeBytes`][PyLong_AsNativeBytes] is problematic for performance
reasons -- especially compared to a `memcpy` with compile-time-constant size).
When one has a *different* integer type, determining the corresponding fixint
means a `sizeof` and signedness check. This is easier and more robust than the
current implementations (see [`wchar_t`][sizeof-wchar_t] or
[`_Bool`][sizeof-bool]).
[swapdefs]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L420-L444
[struct-chars]: https://docs.python.org/3/library/struct.html#format-characters
[current-impls-1]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L470-L653
[current-impls-2]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L703-L944
[memcpy]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L613
[PyLong_AsNativeBytes]: https://docs.python.org/3/c-api/long.html#c.PyLong_AsNativeBytes
[sizeof-wchar_t]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L1547-L1555
[sizeof-bool]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L1562-L1572
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
- Add a helper to set an error from locale-encoded `char*`
- Use the helper for gdbm & dlerror messages
Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
Co-authored-by: Petr Viktorin <encukou@gmail.com>
For dlsym(), a return value of NULL does not necessarily indicate
an error [1].
Therefore, to avoid using stale (or NULL) dlerror() values, we must:
1. clear the previous error state by calling dlerror()
2. call dlsym()
3. call dlerror()
If the return value of dlerror() is not NULL, an error occured.
In ctypes we choose to treat a NULL return value from dlsym()
as a "not found" error. This is the same as the fallback
message we use on Windows, Cygwin or when getting/formatting
the error reason fails.
[1]: https://man7.org/linux/man-pages/man3/dlsym.3.html
Signed-off-by: Georgios Alexopoulos <grgalex42@gmail.com>
Signed-off-by: Georgios Alexopoulos <grgalex@ba.uoa.gr>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Petr Viktorin <encukou@gmail.com>
