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/* A Lib object is what is in the "lib" attribute of a C extension
module originally created by recompile().
A Lib object is special in the sense that it has a custom
__getattr__ which returns C globals, functions and constants. The
original idea was to raise AttributeError for anything else, even
attrs like '__class__', but it breaks various things; now, standard
attrs are returned, but in the unlikely case where a user cdef()s
the same name, then the standard attr is hidden (and the various
things like introspection might break).
A Lib object has got a reference to the _cffi_type_context_s
structure, which is used to create lazily the objects returned by
__getattr__.
*/
struct CPyExtFunc_s {
PyMethodDef md;
void *direct_fn;
int type_index;
char doc[1];
};
struct LibObject_s {
PyObject_HEAD
builder_c_t *l_types_builder; /* same as the one on the ffi object */
PyObject *l_dict; /* content, built lazily */
PyObject *l_libname; /* some string that gives the name of the lib */
FFIObject *l_ffi; /* reference back to the ffi object */
void *l_libhandle; /* the dlopen()ed handle, if any */
};
static struct CPyExtFunc_s *_cpyextfunc_get(PyObject *x)
{
PyObject *y;
LibObject *lo;
PyCFunctionObject *fo;
if (!PyCFunction_Check(x))
return NULL;
y = PyCFunction_GET_SELF(x);
if (!LibObject_Check(y))
return NULL;
fo = (PyCFunctionObject *)x;
lo = (LibObject *)y;
if (lo->l_libname != fo->m_module)
return NULL;
return (struct CPyExtFunc_s *)(fo->m_ml);
}
static PyObject *_cpyextfunc_type(LibObject *lib, struct CPyExtFunc_s *exf)
{
PyObject *tuple, *result;
tuple = realize_c_type_or_func(lib->l_types_builder,
lib->l_types_builder->ctx.types,
exf->type_index);
if (tuple == NULL)
return NULL;
/* 'tuple' is a tuple of length 1 containing the real CT_FUNCTIONPTR
object */
result = PyTuple_GetItem(tuple, 0);
Py_XINCREF(result);
Py_DECREF(tuple);
return result;
}
static PyObject *_cpyextfunc_type_index(PyObject *x)
{
struct CPyExtFunc_s *exf;
LibObject *lib;
assert(PyErr_Occurred());
exf = _cpyextfunc_get(x);
if (exf == NULL)
return NULL; /* still the same exception is set */
PyErr_Clear();
lib = (LibObject *)PyCFunction_GET_SELF(x);
return _cpyextfunc_type(lib, exf);
}
static void cdlopen_close_ignore_errors(void *libhandle); /* forward */
static void *cdlopen_fetch(PyObject *libname, void *libhandle,
const char *symbol);
static void lib_dealloc(LibObject *lib)
{
PyObject_GC_UnTrack(lib);
cdlopen_close_ignore_errors(lib->l_libhandle);
Py_DECREF(lib->l_dict);
Py_DECREF(lib->l_libname);
Py_DECREF(lib->l_ffi);
PyObject_GC_Del(lib);
}
static int lib_traverse(LibObject *lib, visitproc visit, void *arg)
{
Py_VISIT(lib->l_dict);
Py_VISIT(lib->l_libname);
Py_VISIT(lib->l_ffi);
return 0;
}
static PyObject *lib_repr(LibObject *lib)
{
return PyText_FromFormat("<Lib object for '%.200s'>",
PyText_AS_UTF8(lib->l_libname));
}
static PyObject *lib_build_cpython_func(LibObject *lib,
const struct _cffi_global_s *g,
const char *s, int flags)
{
/* First make sure the argument types and return type are really
built. The C extension code can then assume that they are,
by calling _cffi_type().
*/
PyObject *result = NULL;
CTypeDescrObject **pfargs = NULL;
CTypeDescrObject *fresult;
Py_ssize_t nargs = 0;
struct CPyExtFunc_s *xfunc;
int i, type_index = _CFFI_GETARG(g->type_op);
_cffi_opcode_t *opcodes = lib->l_types_builder->ctx.types;
static const char *const format = ";\n\nCFFI C function from %s.lib";
const char *libname = PyText_AS_UTF8(lib->l_libname);
struct funcbuilder_s funcbuilder;
/* return type: */
fresult = realize_c_func_return_type(lib->l_types_builder, opcodes,
type_index);
if (fresult == NULL)
goto error;
/* argument types: */
/* note that if the arguments are already built, they have a
pointer in the 'opcodes' array, and GETOP() returns a
random even value. But OP_FUNCTION_END is odd, so the
condition below still works correctly. */
i = type_index + 1;
while (_CFFI_GETOP(opcodes[i]) != _CFFI_OP_FUNCTION_END)
i++;
pfargs = alloca(sizeof(CTypeDescrObject *) * (i - type_index - 1));
i = type_index + 1;
while (_CFFI_GETOP(opcodes[i]) != _CFFI_OP_FUNCTION_END) {
CTypeDescrObject *ct = realize_c_type(lib->l_types_builder, opcodes, i);
if (ct == NULL)
goto error;
pfargs[nargs++] = ct;
i++;
}
memset(&funcbuilder, 0, sizeof(funcbuilder));
if (fb_build_name(&funcbuilder, g->name, pfargs, nargs, fresult, 0) < 0)
goto error;
/* The few bytes of memory we allocate here appear to leak, but
this is not a real leak. Indeed, CPython never unloads its C
extension modules. There is only one PyMem_Malloc() per real
C function in a CFFI C extension module. That means that this
PyMem_Malloc() could also have been written with a static
global variable generated for each CPYTHON_BLTN defined in the
C extension, and the effect would be the same (but a bit more
complicated).
*/
xfunc = PyMem_Malloc(sizeof(struct CPyExtFunc_s) +
funcbuilder.nb_bytes +
strlen(format) + strlen(libname));
if (xfunc == NULL) {
PyErr_NoMemory();
goto error;
}
memset((char *)xfunc, 0, sizeof(struct CPyExtFunc_s));
assert(g->address);
xfunc->md.ml_meth = (PyCFunction)g->address;
xfunc->md.ml_flags = flags;
xfunc->md.ml_name = g->name;
xfunc->md.ml_doc = xfunc->doc;
xfunc->direct_fn = g->size_or_direct_fn;
xfunc->type_index = type_index;
/* build the docstring */
funcbuilder.bufferp = xfunc->doc;
if (fb_build_name(&funcbuilder, g->name, pfargs, nargs, fresult, 0) < 0)
goto error;
sprintf(funcbuilder.bufferp - 1, format, libname);
/* done building the docstring */
result = PyCFunction_NewEx(&xfunc->md, (PyObject *)lib, lib->l_libname);
/* fall-through */
error:
Py_XDECREF(fresult);
while (nargs > 0) {
--nargs;
Py_DECREF(pfargs[nargs]);
}
return result;
}
static PyObject *lib_build_and_cache_attr(LibObject *lib, PyObject *name,
int recursion)
{
/* does not return a new reference! */
PyObject *x;
int index;
const struct _cffi_global_s *g;
CTypeDescrObject *ct;
builder_c_t *types_builder = lib->l_types_builder;
const char *s = PyText_AsUTF8(name);
if (s == NULL)
return NULL;
index = search_in_globals(&types_builder->ctx, s, strlen(s));
if (index < 0) {
if (types_builder->included_libs != NULL) {
Py_ssize_t i;
PyObject *included_ffis = types_builder->included_ffis;
PyObject *included_libs = types_builder->included_libs;
if (recursion > 100) {
PyErr_SetString(PyExc_RuntimeError,
"recursion overflow in ffi.include() delegations");
return NULL;
}
for (i = 0; i < PyTuple_GET_SIZE(included_libs); i++) {
LibObject *lib1;
lib1 = (LibObject *)PyTuple_GET_ITEM(included_libs, i);
if (lib1 != NULL) {
x = PyDict_GetItem(lib1->l_dict, name);
if (x != NULL) {
Py_INCREF(x);
goto found;
}
x = lib_build_and_cache_attr(lib1, name, recursion + 1);
if (x != NULL) {
Py_INCREF(x);
goto found;
}
}
else {
FFIObject *ffi1;
ffi1 = (FFIObject *)PyTuple_GetItem(included_ffis, i);
if (ffi1 == NULL)
return NULL;
x = ffi_fetch_int_constant(ffi1, s, recursion + 1);
if (x != NULL)
goto found;
}
if (PyErr_Occurred())
return NULL;
}
}
if (recursion > 0)
return NULL; /* no error set, continue looking elsewhere */
PyErr_Format(PyExc_AttributeError,
"cffi library '%.200s' has no function, constant "
"or global variable named '%.200s'",
PyText_AS_UTF8(lib->l_libname), s);
return NULL;
}
g = &types_builder->ctx.globals[index];
switch (_CFFI_GETOP(g->type_op)) {
case _CFFI_OP_CPYTHON_BLTN_V:
x = lib_build_cpython_func(lib, g, s, METH_VARARGS);
break;
case _CFFI_OP_CPYTHON_BLTN_N:
x = lib_build_cpython_func(lib, g, s, METH_NOARGS);
break;
case _CFFI_OP_CPYTHON_BLTN_O:
x = lib_build_cpython_func(lib, g, s, METH_O);
break;
case _CFFI_OP_CONSTANT_INT:
case _CFFI_OP_ENUM:
{
/* a constant integer whose value, in an "unsigned long long",
is obtained by calling the function at g->address */
x = realize_global_int(types_builder, index);
break;
}
case _CFFI_OP_CONSTANT:
case _CFFI_OP_DLOPEN_CONST:
{
/* a constant which is not of integer type */
char *data;
ct = realize_c_type(types_builder, types_builder->ctx.types,
_CFFI_GETARG(g->type_op));
if (ct == NULL)
return NULL;
if (ct->ct_size <= 0) {
PyErr_Format(FFIError, "constant '%s' is of type '%s', "
"whose size is not known", s, ct->ct_name);
return NULL;
}
if (g->address == NULL) {
/* for dlopen() style */
assert(_CFFI_GETOP(g->type_op) == _CFFI_OP_DLOPEN_CONST);
data = cdlopen_fetch(lib->l_libname, lib->l_libhandle, s);
if (data == NULL)
return NULL;
}
else {
/* The few bytes of memory we allocate here appear to leak, but
this is not a real leak. Indeed, CPython never unloads its C
extension modules. There is only one PyMem_Malloc() per real
non-integer C constant in a CFFI C extension module. That
means that this PyMem_Malloc() could also have been written
with a static global variable generated for each OP_CONSTANT
defined in the C extension, and the effect would be the same
(but a bit more complicated).
Note that we used to do alloca(), but see issue #198. We
could still do alloca(), or explicit PyMem_Free(), in some
cases; but there is no point and it only makes the remaining
less-common cases more suspicious.
*/
assert(_CFFI_GETOP(g->type_op) == _CFFI_OP_CONSTANT);
data = PyMem_Malloc(ct->ct_size);
if (data == NULL) {
PyErr_NoMemory();
return NULL;
}
((void(*)(char*))g->address)(data);
}
x = convert_to_object(data, ct);
Py_DECREF(ct);
break;
}
case _CFFI_OP_GLOBAL_VAR:
{
/* global variable of the exact type specified here
(nowadays, only used by the ABI mode or backward
compatibility; see _CFFI_OP_GLOBAL_VAR_F for the API mode)
*/
Py_ssize_t g_size = (Py_ssize_t)g->size_or_direct_fn;
ct = realize_c_type(types_builder, types_builder->ctx.types,
_CFFI_GETARG(g->type_op));
if (ct == NULL)
return NULL;
if (g_size != ct->ct_size && g_size != 0 && ct->ct_size > 0) {
PyErr_Format(FFIError,
"global variable '%.200s' should be %zd bytes "
"according to the cdef, but is actually %zd",
s, ct->ct_size, g_size);
x = NULL;
}
else {
void *address = g->address;
if (address == NULL) {
/* for dlopen() style */
address = cdlopen_fetch(lib->l_libname, lib->l_libhandle, s);
if (address == NULL)
return NULL;
}
x = make_global_var(name, ct, address, NULL);
}
Py_DECREF(ct);
break;
}
case _CFFI_OP_GLOBAL_VAR_F:
ct = realize_c_type(types_builder, types_builder->ctx.types,
_CFFI_GETARG(g->type_op));
if (ct == NULL)
return NULL;
x = make_global_var(name, ct, NULL, (gs_fetch_addr_fn)g->address);
Py_DECREF(ct);
break;
case _CFFI_OP_DLOPEN_FUNC:
{
/* For dlopen(): the function of the given 'name'. We use
dlsym() to get the address of something in the dynamic
library, which we interpret as being exactly a function of
the specified type.
*/
PyObject *ct1;
void *address = cdlopen_fetch(lib->l_libname, lib->l_libhandle, s);
if (address == NULL)
return NULL;
ct1 = realize_c_type_or_func(types_builder,
types_builder->ctx.types,
_CFFI_GETARG(g->type_op));
if (ct1 == NULL)
return NULL;
assert(!CTypeDescr_Check(ct1)); /* must be a function */
x = new_simple_cdata(address, unwrap_fn_as_fnptr(ct1));
Py_DECREF(ct1);
break;
}
case _CFFI_OP_EXTERN_PYTHON:
/* for reading 'lib.bar' where bar is declared with extern "Python" */
ct = realize_c_type(types_builder, types_builder->ctx.types,
_CFFI_GETARG(g->type_op));
if (ct == NULL)
return NULL;
x = convert_to_object((char *)&g->size_or_direct_fn, ct);
Py_DECREF(ct);
break;
default:
PyErr_Format(PyExc_NotImplementedError, "in lib_build_attr: op=%d",
(int)_CFFI_GETOP(g->type_op));
return NULL;
}
found:
if (x != NULL) {
int err = PyDict_SetItem(lib->l_dict, name, x);
Py_DECREF(x);
if (err < 0) /* else there is still one ref left in the dict */
return NULL;
}
return x;
}
#define LIB_GET_OR_CACHE_ADDR(x, lib, name, error) \
do { \
x = PyDict_GetItem(lib->l_dict, name); \
if (x == NULL) { \
x = lib_build_and_cache_attr(lib, name, 0); \
if (x == NULL) { \
error; \
} \
} \
} while (0)
static PyObject *_lib_dir1(LibObject *lib, int ignore_global_vars)
{
const struct _cffi_global_s *g = lib->l_types_builder->ctx.globals;
int i, count = 0, total = lib->l_types_builder->ctx.num_globals;
PyObject *s, *lst = PyList_New(total);
if (lst == NULL)
return NULL;
for (i = 0; i < total; i++) {
if (ignore_global_vars) {
int op = _CFFI_GETOP(g[i].type_op);
if (op == _CFFI_OP_GLOBAL_VAR || op == _CFFI_OP_GLOBAL_VAR_F)
continue;
}
s = PyText_FromString(g[i].name);
if (s == NULL)
goto error;
PyList_SET_ITEM(lst, count, s);
count++;
}
if (PyList_SetSlice(lst, count, total, NULL) < 0)
goto error;
return lst;
error:
Py_DECREF(lst);
return NULL;
}
static PyObject *_lib_dict(LibObject *lib)
{
const struct _cffi_global_s *g = lib->l_types_builder->ctx.globals;
int i, total = lib->l_types_builder->ctx.num_globals;
PyObject *name, *x, *d = PyDict_New();
if (d == NULL)
return NULL;
for (i = 0; i < total; i++) {
name = PyText_FromString(g[i].name);
if (name == NULL)
goto error;
LIB_GET_OR_CACHE_ADDR(x, lib, name, goto error);
if (PyDict_SetItem(d, name, x) < 0)
goto error;
Py_DECREF(name);
}
return d;
error:
Py_XDECREF(name);
Py_DECREF(d);
return NULL;
}
static PyObject *lib_getattr(LibObject *lib, PyObject *name)
{
const char *p;
PyObject *x;
LIB_GET_OR_CACHE_ADDR(x, lib, name, goto missing);
if (GlobSupport_Check(x)) {
return read_global_var((GlobSupportObject *)x);
}
Py_INCREF(x);
return x;
missing:
/*** ATTRIBUTEERROR IS SET HERE ***/
p = PyText_AsUTF8(name);
if (p == NULL)
return NULL;
if (strcmp(p, "__all__") == 0) {
PyErr_Clear();
return _lib_dir1(lib, 1);
}
if (strcmp(p, "__dict__") == 0) {
PyErr_Clear();
return _lib_dict(lib);
}
if (strcmp(p, "__class__") == 0) {
PyErr_Clear();
x = (PyObject *)&PyModule_Type;
/* ^^^ used to be Py_TYPE(lib). But HAAAAAACK! That makes
help() behave correctly. I couldn't find a more reasonable
way. Urgh. */
Py_INCREF(x);
return x;
}
/* this hack is for Python 3.5, and also to give a more
module-like behavior */
if (strcmp(p, "__name__") == 0) {
PyErr_Clear();
return PyText_FromFormat("%s.lib", PyText_AS_UTF8(lib->l_libname));
}
#if PY_MAJOR_VERSION >= 3
if (strcmp(p, "__loader__") == 0 || strcmp(p, "__spec__") == 0) {
/* some more module-like behavior hacks */
PyErr_Clear();
Py_INCREF(Py_None);
return Py_None;
}
#endif
return NULL;
}
static int lib_setattr(LibObject *lib, PyObject *name, PyObject *val)
{
PyObject *x;
LIB_GET_OR_CACHE_ADDR(x, lib, name, return -1);
if (val == NULL) {
PyErr_SetString(PyExc_AttributeError, "C attribute cannot be deleted");
return -1;
}
if (GlobSupport_Check(x)) {
return write_global_var((GlobSupportObject *)x, val);
}
PyErr_Format(PyExc_AttributeError,
"cannot write to function or constant '%.200s'",
PyText_Check(name) ? PyText_AS_UTF8(name) : "?");
return -1;
}
static PyObject *lib_dir(PyObject *self, PyObject *noarg)
{
return _lib_dir1((LibObject *)self, 0);
}
static PyMethodDef lib_methods[] = {
{"__dir__", lib_dir, METH_NOARGS},
{NULL, NULL} /* sentinel */
};
static PyTypeObject Lib_Type = {
PyVarObject_HEAD_INIT(NULL, 0)
"CompiledLib",
sizeof(LibObject),
0,
(destructor)lib_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
(reprfunc)lib_repr, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
(getattrofunc)lib_getattr, /* tp_getattro */
(setattrofunc)lib_setattr, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
(traverseproc)lib_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
lib_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
offsetof(LibObject, l_dict), /* tp_dictoffset */
};
static LibObject *lib_internal_new(FFIObject *ffi, const char *module_name,
void *dlopen_libhandle)
{
LibObject *lib;
PyObject *libname, *dict;
libname = PyText_FromString(module_name);
if (libname == NULL)
goto err1;
dict = PyDict_New();
if (dict == NULL)
goto err2;
lib = (LibObject *)PyType_GenericAlloc(&Lib_Type, 0);
if (lib == NULL)
goto err3;
lib->l_types_builder = &ffi->types_builder;
lib->l_dict = dict;
lib->l_libname = libname;
Py_INCREF(ffi);
lib->l_ffi = ffi;
lib->l_libhandle = dlopen_libhandle;
return lib;
err3:
Py_DECREF(dict);
err2:
Py_DECREF(libname);
err1:
cdlopen_close_ignore_errors(dlopen_libhandle);
return NULL;
}
static PyObject *address_of_global_var(PyObject *args)
{
LibObject *lib;
PyObject *x, *o_varname;
char *varname;
if (!PyArg_ParseTuple(args, "O!s", &Lib_Type, &lib, &varname))
return NULL;
/* rebuild a string from 'varname', to do typechecks and to force
a unicode back to a plain string (on python 2) */
o_varname = PyText_FromString(varname);
if (o_varname == NULL)
return NULL;
LIB_GET_OR_CACHE_ADDR(x, lib, o_varname, goto error);
Py_DECREF(o_varname);
if (GlobSupport_Check(x)) {
return cg_addressof_global_var((GlobSupportObject *)x);
}
else {
struct CPyExtFunc_s *exf = _cpyextfunc_get(x);
if (exf != NULL) { /* an OP_CPYTHON_BLTN: '&func' returns a cdata */
PyObject *ct;
if (exf->direct_fn == NULL) {
Py_INCREF(x); /* backward compatibility */
return x;
}
ct = _cpyextfunc_type(lib, exf);
if (ct == NULL)
return NULL;
x = new_simple_cdata(exf->direct_fn, (CTypeDescrObject *)ct);
Py_DECREF(ct);
return x;
}
if (CData_Check(x) && /* a constant functionptr cdata: 'f == &f' */
(((CDataObject *)x)->c_type->ct_flags & CT_FUNCTIONPTR) != 0) {
Py_INCREF(x);
return x;
}
else {
PyErr_Format(PyExc_AttributeError,
"cannot take the address of the constant '%.200s'",
varname);
return NULL;
}
}
error:
Py_DECREF(o_varname);
return NULL;
}