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Fixed bpo-29565: Corrected ctypes passing of large structs by value o… · python/cpython@3cc5817

4 files changed

lines changed

Original file line numberDiff line numberDiff line change

@@ -244,6 +244,7 @@ def callback(a, b, c, d, e):

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def test_callback_large_struct(self):

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class Check: pass

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# This should mirror the structure in Modules/_ctypes/_ctypes_test.c

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class X(Structure):

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_fields_ = [

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('first', c_ulong),

@@ -255,6 +256,11 @@ def callback(check, s):

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check.first = s.first

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check.second = s.second

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check.third = s.third

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# See issue #29565.

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# The structure should be passed by value, so

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# any changes to it should not be reflected in

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# the value passed

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s.first = s.second = s.third = 0x0badf00d

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check = Check()

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s = X()

@@ -275,6 +281,11 @@ def callback(check, s):

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self.assertEqual(check.first, 0xdeadbeef)

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self.assertEqual(check.second, 0xcafebabe)

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self.assertEqual(check.third, 0x0bad1dea)

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# See issue #29565.

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# Ensure that the original struct is unchanged.

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self.assertEqual(s.first, check.first)

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self.assertEqual(s.second, check.second)

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self.assertEqual(s.third, check.third)

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################################################################

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Original file line numberDiff line numberDiff line change

@@ -3,6 +3,7 @@

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from ctypes.test import need_symbol

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from struct import calcsize

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import _testcapi

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import _ctypes_test

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class SubclassesTest(unittest.TestCase):

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def test_subclass(self):

@@ -391,6 +392,28 @@ class Z(Y):

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(1, 0, 0, 0, 0, 0))

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self.assertRaises(TypeError, lambda: Z(1, 2, 3, 4, 5, 6, 7))

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def test_pass_by_value(self):

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# This should mirror the structure in Modules/_ctypes/_ctypes_test.c

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class X(Structure):

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_fields_ = [

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('first', c_ulong),

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('second', c_ulong),

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('third', c_ulong),

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]

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s = X()

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s.first = 0xdeadbeef

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s.second = 0xcafebabe

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s.third = 0x0bad1dea

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dll = CDLL(_ctypes_test.__file__)

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func = dll._testfunc_large_struct_update_value

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func.argtypes = (X,)

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func.restype = None

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func(s)

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self.assertEqual(s.first, 0xdeadbeef)

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self.assertEqual(s.second, 0xcafebabe)

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self.assertEqual(s.third, 0x0bad1dea)

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class PointerMemberTestCase(unittest.TestCase):

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def test(self):

Original file line numberDiff line numberDiff line change

@@ -44,6 +44,19 @@ _testfunc_cbk_large_struct(Test in, void (*func)(Test))

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func(in);

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}

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/*

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* See issue 29565. Update a structure passed by value;

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* the caller should not see any change.

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*/

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EXPORT(void)

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_testfunc_large_struct_update_value(Test in)

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{

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in.first = 0x0badf00d;

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in.second = 0x0badf00d;

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in.third = 0x0badf00d;

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}

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EXPORT(void)testfunc_array(int values[4])

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{

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printf("testfunc_array %d %d %d %d\n",

Original file line numberDiff line numberDiff line change

@@ -239,6 +239,16 @@ ffi_call(/*@dependent@*/ ffi_cif *cif,

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break;

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#else

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case FFI_SYSV:

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/* If a single argument takes more than 8 bytes,

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then a copy is passed by reference. */

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for (unsigned i = 0; i < cif->nargs; i++) {

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size_t z = cif->arg_types[i]->size;

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if (z > 8) {

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void *temp = alloca(z);

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memcpy(temp, avalue[i], z);

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avalue[i] = temp;

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}

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}

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/*@-usedef@*/

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return ffi_call_AMD64(ffi_prep_args, &ecif, cif->bytes,

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cif->flags, ecif.rvalue, fn);