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bpo-44689: ctypes.util.find_library() now finds macOS 11+ system libraries when built on older macOS systems #27251

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Merged
ned-deily merged 7 commits into from
Aug 30, 2021
Merged

bpo-44689: ctypes.util.find_library() now finds macOS 11+ system libraries when built on older macOS systems #27251

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0858c0c
Add _ctypes.shared_library_is_loadable. Remove _ctypes._dyld_shared_c…
bergkvist Jul 20, 2021
b7aa289
Fix test_ctypes for Windows.
bergkvist Jul 20, 2021
00388a2
📜🤖 Added by blurb_it.
blurb-it[bot] Jul 20, 2021
9d3c834
bpo-44689: Remove dlopen in find_library. Load _dyld_shared_cache_con…
bergkvist Jul 27, 2021
01bcf2b
Update Misc/NEWS.d/next/macOS/2021-07-20-22-27-01.bpo-44689.mmT_xH.rst
bergkvist Jul 27, 2021
52473a4
bpo-44689: Revert to using weak linking implementation. Only use dyna…
bergkvist Aug 6, 2021
dfcc357
bpo-44689: edit NEWS blurb and comment
ned-deily Aug 30, 2021
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/macOS/2021-07-20-22-27-01.bpo-44689.mmT_xH.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
You can now compile Python on MacOS < 11.0 and
:meth:`ctypes.util.find_library` will still work on MacOS >= 11.0.
29 changes: 26 additions & 3 deletions Modules/_ctypes/callproc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1442,14 +1442,37 @@ copy_com_pointer(PyObject *self, PyObject *args)
return r;
}
#else

#ifdef __APPLE__
#ifdef HAVE_DYLD_SHARED_CACHE_CONTAINS_PATH
#define HAVE_DYLD_SHARED_CACHE_CONTAINS_PATH_RUNTIME \
__builtin_available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
#else
// Support the deprecated case of compiling on an older MacOS version
static void *libsystem_b_handle;
static bool (*_dyld_shared_cache_contains_path)(const char *path);

__attribute__((constructor)) void load_dyld_shared_cache_contains_path(void) {
libsystem_b_handle = dlopen("/usr/lib/libSystem.B.dylib", RTLD_LAZY);
if (libsystem_b_handle != NULL) {
_dyld_shared_cache_contains_path = dlsym(libsystem_b_handle, "_dyld_shared_cache_contains_path");
}
}

__attribute__((destructor)) void unload_dyld_shared_cache_contains_path(void) {
if (libsystem_b_handle != NULL) {
dlclose(libsystem_b_handle);
}
}
#define HAVE_DYLD_SHARED_CACHE_CONTAINS_PATH_RUNTIME \
_dyld_shared_cache_contains_path != NULL
#endif

static PyObject *py_dyld_shared_cache_contains_path(PyObject *self, PyObject *args)
{
PyObject *name, *name2;
char *name_str;

if (__builtin_available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)) {
if (HAVE_DYLD_SHARED_CACHE_CONTAINS_PATH_RUNTIME) {
int r;

if (!PyArg_ParseTuple(args, "O", &name))
Expand Down Expand Up @@ -1992,7 +2015,7 @@ PyMethodDef _ctypes_module_methods[] = {
{"dlclose", py_dl_close, METH_VARARGS, "dlclose a library"},
{"dlsym", py_dl_sym, METH_VARARGS, "find symbol in shared library"},
#endif
#ifdef HAVE_DYLD_SHARED_CACHE_CONTAINS_PATH
#ifdef __APPLE__
{"_dyld_shared_cache_contains_path", py_dyld_shared_cache_contains_path, METH_VARARGS, "check if path is in the shared cache"},
#endif
{"alignment", align_func, METH_O, alignment_doc},
Expand Down