glib/girepository/girffi.c

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2012-02-03 19:42:56 +01:00
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
* GObject introspection: Helper functions for ffi integration
*
* Copyright (C) 2008 Red Hat, Inc
* Copyright (C) 2005 Matthias Clasen
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include <sys/types.h>
#include <errno.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "girffi.h"
#include "gibaseinfo-private.h"
#include "girepository.h"
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#include "girepository-private.h"
static ffi_type *
gi_type_tag_get_ffi_type_internal (GITypeTag tag,
gboolean is_pointer,
gboolean is_enum)
{
switch (tag)
{
case GI_TYPE_TAG_BOOLEAN:
return &ffi_type_uint;
case GI_TYPE_TAG_INT8:
return &ffi_type_sint8;
case GI_TYPE_TAG_UINT8:
return &ffi_type_uint8;
case GI_TYPE_TAG_INT16:
return &ffi_type_sint16;
case GI_TYPE_TAG_UINT16:
return &ffi_type_uint16;
case GI_TYPE_TAG_INT32:
return &ffi_type_sint32;
case GI_TYPE_TAG_UINT32:
case GI_TYPE_TAG_UNICHAR:
return &ffi_type_uint32;
case GI_TYPE_TAG_INT64:
return &ffi_type_sint64;
case GI_TYPE_TAG_UINT64:
return &ffi_type_uint64;
case GI_TYPE_TAG_GTYPE:
#if GLIB_SIZEOF_SIZE_T == 4
return &ffi_type_uint32;
#elif GLIB_SIZEOF_SIZE_T == 8
return &ffi_type_uint64;
#else
# error "Unexpected size for size_t: not 4 or 8"
#endif
case GI_TYPE_TAG_FLOAT:
return &ffi_type_float;
case GI_TYPE_TAG_DOUBLE:
return &ffi_type_double;
case GI_TYPE_TAG_UTF8:
case GI_TYPE_TAG_FILENAME:
case GI_TYPE_TAG_ARRAY:
case GI_TYPE_TAG_GLIST:
case GI_TYPE_TAG_GSLIST:
case GI_TYPE_TAG_GHASH:
case GI_TYPE_TAG_ERROR:
return &ffi_type_pointer;
case GI_TYPE_TAG_INTERFACE:
{
/* We need to handle enums specially:
* https://bugzilla.gnome.org/show_bug.cgi?id=665150
*/
if (!is_enum)
return &ffi_type_pointer;
else
return &ffi_type_sint32;
}
case GI_TYPE_TAG_VOID:
if (is_pointer)
return &ffi_type_pointer;
else
return &ffi_type_void;
default:
break;
}
g_assert_not_reached ();
return NULL;
}
/**
* gi_type_tag_get_ffi_type:
* @type_tag: a #GITypeTag
* @is_pointer: whether this is a pointer type
*
* Get the `ffi_type` corresponding to @type_tag.
*
* Returns: (transfer none): an `ffi_type` corresponding to the platform default
* C ABI for @tag and @is_pointer.
* Since: 2.80
*/
ffi_type *
gi_type_tag_get_ffi_type (GITypeTag type_tag,
gboolean is_pointer)
{
return gi_type_tag_get_ffi_type_internal (type_tag, is_pointer, FALSE);
}
/**
* gi_type_info_get_ffi_type:
* @info: a #GITypeInfo
*
* Get the `ffi_type` corresponding to @info.
*
* Returns: (transfer none): a `ffi_type` corresponding to the platform default
* C ABI for @info.
* Since: 2.80
*/
ffi_type *
gi_type_info_get_ffi_type (GITypeInfo *info)
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{
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gboolean is_enum = FALSE;
GIBaseInfo *iinfo;
if (gi_type_info_get_tag (info) == GI_TYPE_TAG_INTERFACE)
{
iinfo = gi_type_info_get_interface (info);
switch (gi_base_info_get_info_type (iinfo))
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{
case GI_INFO_TYPE_ENUM:
case GI_INFO_TYPE_FLAGS:
is_enum = TRUE;
break;
default:
break;
}
gi_base_info_unref (iinfo);
}
return gi_type_tag_get_ffi_type_internal (gi_type_info_get_tag (info), gi_type_info_is_pointer (info), is_enum);
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}
/**
* gi_callable_info_get_ffi_arg_types:
* @callable_info: a callable info from a typelib
* @n_args_p: (out) (optional): the number of arguments returned
*
* Get the `ffi_type`s for the arguments of @callable_info.
*
* Returns: (transfer container) (array length=n_args_p): an array of
* `ffi_type*`. The array itself should be freed using [func@GLib.free] after
* use.
* Since: 2.80
*/
static ffi_type **
gi_callable_info_get_ffi_arg_types (GICallableInfo *callable_info,
size_t *n_args_p)
{
ffi_type **arg_types;
gboolean is_method, throws;
size_t n_args, n_invoke_args, i, offset;
g_return_val_if_fail (callable_info != NULL, NULL);
n_args = gi_callable_info_get_n_args (callable_info);
is_method = gi_callable_info_is_method (callable_info);
throws = gi_callable_info_can_throw_gerror (callable_info);
offset = is_method ? 1 : 0;
n_invoke_args = n_args;
if (is_method)
n_invoke_args++;
if (throws)
n_invoke_args++;
if (n_args_p)
*n_args_p = n_invoke_args;
arg_types = (ffi_type **) g_new0 (ffi_type *, n_invoke_args + 1);
if (is_method)
arg_types[0] = &ffi_type_pointer;
if (throws)
arg_types[n_invoke_args - 1] = &ffi_type_pointer;
for (i = 0; i < n_args; ++i)
{
GIArgInfo arg_info;
GITypeInfo arg_type;
gi_callable_info_load_arg (callable_info, i, &arg_info);
gi_arg_info_load_type_info (&arg_info, &arg_type);
switch (gi_arg_info_get_direction (&arg_info))
{
case GI_DIRECTION_IN:
arg_types[i + offset] = gi_type_info_get_ffi_type (&arg_type);
break;
case GI_DIRECTION_OUT:
case GI_DIRECTION_INOUT:
arg_types[i + offset] = &ffi_type_pointer;
break;
default:
g_assert_not_reached ();
}
gi_base_info_clear (&arg_type);
gi_base_info_clear (&arg_info);
}
arg_types[n_invoke_args] = NULL;
return arg_types;
}
/**
* gi_callable_info_get_ffi_return_type:
* @callable_info: a callable info from a typelib
*
* Fetches the `ffi_type` for a corresponding return value of
* a [class@GIRepository.CallableInfo].
*
* Returns: (transfer none): the `ffi_type` for the return value
* Since: 2.80
*/
static ffi_type *
gi_callable_info_get_ffi_return_type (GICallableInfo *callable_info)
{
GITypeInfo *return_type;
ffi_type *return_ffi_type;
g_return_val_if_fail (callable_info != NULL, NULL);
return_type = gi_callable_info_get_return_type (callable_info);
return_ffi_type = gi_type_info_get_ffi_type (return_type);
gi_base_info_unref((GIBaseInfo*)return_type);
return return_ffi_type;
}
/**
* gi_function_info_prep_invoker:
* @info: A #GIFunctionInfo
* @invoker: (out caller-allocates): Output invoker structure
* @error: A #GError
*
* Initialize the caller-allocated @invoker structure with a cache
* of information needed to invoke the C function corresponding to
* @info with the platforms default ABI.
*
* A primary intent of this function is that a dynamic structure allocated
* by a language binding could contain a [type@GIRepository.FunctionInvoker]
* structure inside the bindings function mapping.
*
* @invoker must be freed using [method@GIRepository.FunctionInvoker.clear]
* when its finished with.
*
* Returns: `TRUE` on success, `FALSE` otherwise with @error set.
* Since: 2.80
*/
gboolean
gi_function_info_prep_invoker (GIFunctionInfo *info,
GIFunctionInvoker *invoker,
GError **error)
{
const char *symbol;
void *addr;
g_return_val_if_fail (info != NULL, FALSE);
g_return_val_if_fail (invoker != NULL, FALSE);
symbol = gi_function_info_get_symbol ((GIFunctionInfo*) info);
if (!gi_typelib_symbol (gi_base_info_get_typelib ((GIBaseInfo *) info),
symbol, &addr))
{
g_set_error (error,
GI_INVOKE_ERROR,
GI_INVOKE_ERROR_SYMBOL_NOT_FOUND,
"Could not locate %s: %s", symbol, g_module_error ());
return FALSE;
}
return gi_function_invoker_new_for_address (addr, (GICallableInfo *) info, invoker, error);
}
/**
* gi_function_invoker_new_for_address:
* @addr: The address
* @info: A #GICallableInfo
* @invoker: (out caller-allocates): Output invoker structure
* @error: A #GError
*
* Initialize the caller-allocated @invoker structure with a cache
* of information needed to invoke the C function corresponding to
* @info with the platforms default ABI.
*
* A primary intent of this function is that a dynamic structure allocated
* by a language binding could contain a [type@GIRepository.FunctionInvoker]
* structure inside the bindings function mapping.
*
* Returns: `TRUE` on success, `FALSE` otherwise with @error set.
* Since: 2.80
*/
gboolean
gi_function_invoker_new_for_address (void *addr,
GICallableInfo *info,
GIFunctionInvoker *invoker,
GError **error)
{
ffi_type **atypes;
size_t n_args;
g_return_val_if_fail (info != NULL, FALSE);
g_return_val_if_fail (invoker != NULL, FALSE);
invoker->native_address = addr;
atypes = gi_callable_info_get_ffi_arg_types (info, &n_args);
return ffi_prep_cif (&(invoker->cif), FFI_DEFAULT_ABI, n_args,
gi_callable_info_get_ffi_return_type (info),
g_steal_pointer (&atypes)) == FFI_OK;
}
/**
* gi_function_invoker_clear:
* @invoker: (transfer none): A #GIFunctionInvoker
*
* Release all resources allocated for the internals of @invoker.
*
* Callers are responsible for freeing any resources allocated for the structure
* itself however.
*
* Since: 2.80
*/
void
gi_function_invoker_clear (GIFunctionInvoker *invoker)
{
g_free (invoker->cif.arg_types);
}
typedef struct {
ffi_closure ffi_closure;
void *writable_self;
void *native_address;
} GIClosureWrapper;
/**
* gi_callable_info_create_closure:
* @callable_info: a callable info from a typelib
* @cif: a `ffi_cif` structure
* @callback: the ffi callback
* @user_data: data to be passed into the callback
*
* Prepares a callback for ffi invocation.
*
* Returns: (transfer full) (nullable): the `ffi_closure`, or `NULL` on error.
* The return value should be freed by calling
* [method@GIRepository.CallableInfo.destroy_closure].
* Since: 2.80
*/
ffi_closure *
gi_callable_info_create_closure (GICallableInfo *callable_info,
ffi_cif *cif,
GIFFIClosureCallback callback,
void *user_data)
{
void *exec_ptr;
size_t n_args;
ffi_type **atypes;
GIClosureWrapper *closure;
ffi_status status;
g_return_val_if_fail (callable_info != NULL, FALSE);
g_return_val_if_fail (cif != NULL, FALSE);
g_return_val_if_fail (callback != NULL, FALSE);
closure = ffi_closure_alloc (sizeof (GIClosureWrapper), &exec_ptr);
if (!closure)
{
g_warning ("could not allocate closure");
return NULL;
}
closure->writable_self = closure;
closure->native_address = exec_ptr;
atypes = gi_callable_info_get_ffi_arg_types (callable_info, &n_args);
status = ffi_prep_cif (cif, FFI_DEFAULT_ABI, n_args,
gi_callable_info_get_ffi_return_type (callable_info),
atypes);
/* Explicitly store atypes to satisfy static analysers, which cant see inside
* ffi_prep_cif(), and hence assume that its leaked. */
cif->arg_types = g_steal_pointer (&atypes);
if (status != FFI_OK)
{
g_warning ("ffi_prep_cif failed: %d", status);
gi_callable_info_destroy_closure (callable_info, &closure->ffi_closure);
return NULL;
}
status = ffi_prep_closure_loc (&closure->ffi_closure, cif, callback, user_data, exec_ptr);
if (status != FFI_OK)
{
g_warning ("ffi_prep_closure failed: %d", status);
gi_callable_info_destroy_closure (callable_info, &closure->ffi_closure);
return NULL;
}
girffi.c: fix return value for g_callable_info_prepare_closure() The initial failure was observed on `meld` against recently released `libffi-3.4-rc1`. There `meld` crashes as: ``` $ meld Segmentation fault (core dumped) $ gdb --args /usr/bin/python3.9 /usr/bin/meld (gdb) run ... Thread 1 "python3.9" received signal SIGSEGV, Segmentation fault. 0x00007fffe9ac1ae8 in g_callable_info_free_closure ( callable_info=0x555555d45990, closure=0x7fffe9e70c20) at ../gobject-introspection-1.68.0/girepository/girffi.c:428 428 g_free (wrapper->ffi_closure.cif->arg_types); (gdb) bt callable_info=0x555555d45990, closure=0x7fffe9e70c20) at ../gobject-introspection-1.68.0/girepository/girffi.c:428 data=0x555555d252d0) at ../pygobject-3.40.1/gi/pygi-closure.c:635 ... ``` The bug here is in type mismatch between expected return value of `g_callable_info_prepare_closure()` and actual value (executable code pointer): ```c ffi_closure * g_callable_info_prepare_closure(...) { gpointer exec_ptr; ... status = ffi_prep_closure_loc (&closure->ffi_closure, cif, callback, user_data, exec_ptr); return exec_ptr; } ``` Note: `exec_ptr` is a code pointer that could be directly executed by caller, like `((rt (*)(a1,a2))exec_ptr)(1,2);` It should never be wrapped into an `ffi_closure*`, which is normally called via `ffi_call(closure, ...)`. We see the problem when we try to free direct code pointer instead of `ffi_closure()` as starting from libffi-3.4 executable trampoline and `ffi_closure()` don't necessarily live in the same block: https://github.com/libffi/libffi/commit/9ba559217bea0803263a9a9a0bafcf9203606f5b Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
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return &closure->ffi_closure;
}
/**
* gi_callable_info_get_closure_native_address:
* @callable_info: a callable info from a typelib
* @closure: ffi closure
*
* Gets callable code from `ffi_closure` prepared by
* [method@GIRepository.CallableInfo.create_closure].
*
* Returns: (transfer none): native address
* Since: 2.80
*/
void **
gi_callable_info_get_closure_native_address (GICallableInfo *callable_info,
ffi_closure *closure)
{
GIClosureWrapper *wrapper = (GIClosureWrapper *)closure;
return wrapper->native_address;
}
/**
* gi_callable_info_destroy_closure:
* @callable_info: a callable info from a typelib
* @closure: (transfer full): ffi closure
*
* Frees a `ffi_closure` returned from
* [method@GIRepository.CallableInfo.create_closure].
*
* Since: 2.80
*/
void
gi_callable_info_destroy_closure (GICallableInfo *callable_info,
ffi_closure *closure)
{
GIClosureWrapper *wrapper = (GIClosureWrapper *)closure;
g_free (wrapper->ffi_closure.cif->arg_types);
ffi_closure_free (wrapper->writable_self);
}