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Fix GH-9090: Support assigning function pointers in FFI #9107

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Fix GH-9090: Support assigning function pointers in FFI #9107

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47 changes: 47 additions & 0 deletions ext/ffi/ffi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -214,6 +214,7 @@ static ZEND_FUNCTION(ffi_trampoline);
static ZEND_COLD void zend_ffi_return_unsupported(zend_ffi_type *type);
static ZEND_COLD void zend_ffi_pass_unsupported(zend_ffi_type *type);
static ZEND_COLD void zend_ffi_assign_incompatible(zval *arg, zend_ffi_type *type);
static bool zend_ffi_is_compatible_type(zend_ffi_type *dst_type, zend_ffi_type *src_type);

#if FFI_CLOSURES
static void *zend_ffi_create_callback(zend_ffi_type *type, zval *value);
Expand Down Expand Up @@ -255,6 +256,49 @@ static zend_object *zend_ffi_cdata_new(zend_class_entry *class_type) /* {{{ */
}
/* }}} */

static bool zend_ffi_func_ptr_are_compatible(zend_ffi_type *dst_type, zend_ffi_type *src_type) /* {{{ */
{
uint32_t dst_argc, src_argc, i;
zend_ffi_type *dst_arg, *src_arg;

ZEND_ASSERT(dst_type->kind == ZEND_FFI_TYPE_FUNC);
ZEND_ASSERT(src_type->kind == ZEND_FFI_TYPE_FUNC);

/* Ensure calling convention matches */
if (dst_type->func.abi != src_type->func.abi) {
return 0;
}

/* Ensure variadic attr matches */
if ((dst_type->attr & ZEND_FFI_ATTR_VARIADIC) != (src_type->attr & ZEND_FFI_ATTR_VARIADIC)) {
return 0;
}

/* Ensure same arg count */
dst_argc = dst_type->func.args ? zend_hash_num_elements(dst_type->func.args) : 0;
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Does this need a check for C varags? Either way, a test for that would be nice.

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Thanks, added a variadic to the test.

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You should check

(src_type->attr & ZEND_FFI_ATTR_VARIADIC) == (dst_type->attr & ZEND_FFI_ATTR_VARIADIC)

Also it's make sense to add check for calling convention

src_type->func.abi == dst_type->func.abi

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Added those checks. Thank you.

src_argc = src_type->func.args ? zend_hash_num_elements(src_type->func.args) : 0;
if (dst_argc != src_argc) {
return 0;
}

/* Ensure compatible ret_type */
if (!zend_ffi_is_compatible_type(dst_type->func.ret_type, src_type->func.ret_type)) {
return 0;
}

/* Ensure compatible args */
for (i = 0; i < dst_argc; i++) {
dst_arg = zend_hash_index_find_ptr(dst_type->func.args, i);
src_arg = zend_hash_index_find_ptr(src_type->func.args, i);
if (!zend_ffi_is_compatible_type(ZEND_FFI_TYPE(dst_arg), ZEND_FFI_TYPE(src_arg))) {
return 0;
}
}

return 1;
}
/* }}} */

static bool zend_ffi_is_compatible_type(zend_ffi_type *dst_type, zend_ffi_type *src_type) /* {{{ */
{
while (1) {
Expand All @@ -269,6 +313,9 @@ static bool zend_ffi_is_compatible_type(zend_ffi_type *dst_type, zend_ffi_type *
if (dst_type->kind == ZEND_FFI_TYPE_VOID ||
src_type->kind == ZEND_FFI_TYPE_VOID) {
return 1;
} else if (dst_type->kind == ZEND_FFI_TYPE_FUNC &&
src_type->kind == ZEND_FFI_TYPE_FUNC) {
return zend_ffi_func_ptr_are_compatible(dst_type, src_type);
}
} else if (dst_type->kind == ZEND_FFI_TYPE_ARRAY &&
(dst_type->array.length == src_type->array.length ||
Expand Down
80 changes: 80 additions & 0 deletions ext/ffi/tests/bug_gh9090.phpt
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@@ -0,0 +1,80 @@
--TEST--
GH-9090 (Support assigning function pointers via FFI)
--EXTENSIONS--
ffi
zend_test
--FILE--
<?php

require_once 'utils.inc';
$h = <<<'EOD'
void (*bug_gh9090_void_none_ptr)();
void (*bug_gh9090_void_int_char_ptr)(int, char *);
void (*bug_gh9090_void_int_char_var_ptr)(int, char *, ...);
void (*bug_gh9090_void_char_int_ptr)(char *, int);
int (*bug_gh9090_int_int_char_ptr)(int, char *);

void bug_gh9090_void_none();
void bug_gh9090_void_int_char(int i, char *s);
void bug_gh9090_void_int_char_var(int i, char *fmt, ...);
EOD;

if (PHP_OS_FAMILY !== 'Windows') {
$ffi = FFI::cdef($h);
} else {
try {
$ffi = FFI::cdef($h, 'php_zend_test.dll');
} catch (FFI\Exception $ex) {
$ffi = FFI::cdef($h, ffi_get_php_dll_name());
}
}

$func_ptrs = [
'bug_gh9090_void_none_ptr',
'bug_gh9090_void_int_char_ptr',
'bug_gh9090_void_int_char_var_ptr',
'bug_gh9090_void_char_int_ptr',
'bug_gh9090_int_int_char_ptr',
];

$func_argvs = [
[ 'bug_gh9090_void_none', [ ] ],
[ 'bug_gh9090_void_int_char', [ 42, "hello" ] ],
[ 'bug_gh9090_void_int_char_var', [ 42, "d=%d s=%s", -1, "ok" ] ],
];

foreach ($func_ptrs as $func_ptr) {
foreach ($func_argvs as $func_argv) {
[ $func, $argv ] = $func_argv;

$ok = true;
try {
$ffi->$func_ptr = $ffi->$func;
call_user_func_array($ffi->$func_ptr, $argv);
} catch (FFI\Exception $e) {
$ok = false;
}

printf("%-36s = %-36s ? %s\n", $func_ptr, $func, $ok ? 'yes' : 'no');
}
}
?>
--EXPECT--
bug_gh9090_none
bug_gh9090_void_none_ptr = bug_gh9090_void_none ? yes
bug_gh9090_void_none_ptr = bug_gh9090_void_int_char ? no
bug_gh9090_void_none_ptr = bug_gh9090_void_int_char_var ? no
bug_gh9090_void_int_char_ptr = bug_gh9090_void_none ? no
bug_gh9090_int_char 42 hello
bug_gh9090_void_int_char_ptr = bug_gh9090_void_int_char ? yes
bug_gh9090_void_int_char_ptr = bug_gh9090_void_int_char_var ? no
bug_gh9090_void_int_char_var_ptr = bug_gh9090_void_none ? no
bug_gh9090_void_int_char_var_ptr = bug_gh9090_void_int_char ? no
bug_gh9090_void_int_char_var d=-1 s=ok
bug_gh9090_void_int_char_var_ptr = bug_gh9090_void_int_char_var ? yes
bug_gh9090_void_char_int_ptr = bug_gh9090_void_none ? no
bug_gh9090_void_char_int_ptr = bug_gh9090_void_int_char ? no
bug_gh9090_void_char_int_ptr = bug_gh9090_void_int_char_var ? no
bug_gh9090_int_int_char_ptr = bug_gh9090_void_none ? no
bug_gh9090_int_int_char_ptr = bug_gh9090_void_int_char ? no
bug_gh9090_int_int_char_ptr = bug_gh9090_void_int_char_var ? no
27 changes: 27 additions & 0 deletions ext/zend_test/test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -847,3 +847,30 @@ PHP_ZEND_TEST_API bug80847_02 ffi_bug80847(bug80847_02 s) {
s.a.c -= 10.0;
return s;
}

PHP_ZEND_TEST_API void (*bug_gh9090_void_none_ptr)(void) = NULL;
PHP_ZEND_TEST_API void (*bug_gh9090_void_int_char_ptr)(int, char *) = NULL;
PHP_ZEND_TEST_API void (*bug_gh9090_void_int_char_var_ptr)(int, char *, ...) = NULL;
PHP_ZEND_TEST_API void (*bug_gh9090_void_char_int_ptr)(char *, int) = NULL;
PHP_ZEND_TEST_API int (*bug_gh9090_int_int_char_ptr)(int, char *) = NULL;

PHP_ZEND_TEST_API void bug_gh9090_void_none(void) {
php_printf("bug_gh9090_none\n");
}

PHP_ZEND_TEST_API void bug_gh9090_void_int_char(int i, char *s) {
php_printf("bug_gh9090_int_char %d %s\n", i, s);
}

PHP_ZEND_TEST_API void bug_gh9090_void_int_char_var(int i, char *fmt, ...) {
va_list args;
char *buffer;

va_start(args, fmt);

zend_vspprintf(&buffer, 0, fmt, args);
php_printf("bug_gh9090_void_int_char_var %s\n", buffer);
efree(buffer);

va_end(args);
}