lib/talloc/pytalloc_util.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Python/Talloc glue
   4    Copyright (C) Jelmer Vernooij <jelmer@samba.org> 2008
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include <Python.h>
  21 #include "replace.h"
  22 #include <talloc.h>
  23 #include "pytalloc.h"
  24 #include <assert.h>
  25 #include "pytalloc_private.h"
  26
  27 _PUBLIC_ PyTypeObject *pytalloc_GetObjectType(void)
  28 {
  29         static PyTypeObject *type = NULL;
  30         PyObject *mod;
  31
  32         if (type != NULL) {
  33                 return type;
  34         }
  35
  36         mod = PyImport_ImportModule("talloc");
  37         if (mod == NULL) {
  38                 return NULL;
  39         }
  40
  41         type = (PyTypeObject *)PyObject_GetAttrString(mod, "Object");
  42         Py_DECREF(mod);
  43
  44         return type;
  45 }
  46
  47 _PUBLIC_ PyTypeObject *pytalloc_GetBaseObjectType(void)
  48 {
  49         static PyTypeObject *type = NULL;
  50         PyObject *mod;
  51
  52         if (type != NULL) {
  53                 return type;
  54         }
  55
  56         mod = PyImport_ImportModule("talloc");
  57         if (mod == NULL) {
  58                 return NULL;
  59         }
  60
  61         type = (PyTypeObject *)PyObject_GetAttrString(mod, "BaseObject");
  62         Py_DECREF(mod);
  63
  64         return type;
  65 }
  66
  67 static PyTypeObject *pytalloc_GetGenericObjectType(void)
  68 {
  69         static PyTypeObject *type = NULL;
  70         PyObject *mod;
  71
  72         if (type != NULL) {
  73                 return type;
  74         }
  75
  76         mod = PyImport_ImportModule("talloc");
  77         if (mod == NULL) {
  78                 return NULL;
  79         }
  80
  81         type = (PyTypeObject *)PyObject_GetAttrString(mod, "GenericObject");
  82         Py_DECREF(mod);
  83
  84         return type;
  85 }
  86
  87 /**
  88  * Import an existing talloc pointer into a Python object.
  89  */
  90 _PUBLIC_ PyObject *pytalloc_steal_ex(PyTypeObject *py_type, TALLOC_CTX *mem_ctx,
  91                                      void *ptr)
  92 {
  93         PyTypeObject *BaseObjectType = pytalloc_GetBaseObjectType();
  94         PyTypeObject *ObjectType = pytalloc_GetObjectType();
  95
  96         if (mem_ctx == NULL) {
  97                 return PyErr_NoMemory();
  98         }
  99
 100         if (PyType_IsSubtype(py_type, BaseObjectType)) {
 101                 pytalloc_BaseObject *ret
 102                         = (pytalloc_BaseObject *)py_type->tp_alloc(py_type, 0);
 103
 104                 ret->talloc_ctx = talloc_new(NULL);
 105                 if (ret->talloc_ctx == NULL) {
 106                         return NULL;
 107                 }
 108
 109                 /*
 110                  * This allows us to keep multiple references to this object -
 111                  * we only reference this context, which is per ptr, not the
 112                  * talloc_ctx, which is per pytalloc_Object
 113                  */
 114                 if (talloc_steal(ret->talloc_ctx, mem_ctx) == NULL) {
 115                         return NULL;
 116                 }
 117                 ret->talloc_ptr_ctx = mem_ctx;
 118                 talloc_set_name_const(ret->talloc_ctx, py_type->tp_name);
 119                 ret->ptr = ptr;
 120                 return (PyObject *)ret;
 121
 122         } else if (PyType_IsSubtype(py_type, ObjectType)) {
 123                 pytalloc_Object *ret
 124                         = (pytalloc_Object *)py_type->tp_alloc(py_type, 0);
 125
 126                 ret->talloc_ctx = talloc_new(NULL);
 127                 if (ret->talloc_ctx == NULL) {
 128                         return NULL;
 129                 }
 130
 131                 if (talloc_steal(ret->talloc_ctx, mem_ctx) == NULL) {
 132                         return NULL;
 133                 }
 134                 talloc_set_name_const(ret->talloc_ctx, py_type->tp_name);
 135                 ret->ptr = ptr;
 136                 return (PyObject *)ret;
 137         } else {
 138                 PyErr_SetString(PyExc_RuntimeError,
 139                                 "pytalloc_steal_ex() called for object type "
 140                                 "not based on talloc");
 141                 return NULL;
 142         }
 143 }
 144
 145 /**
 146  * Import an existing talloc pointer into a Python object.
 147  */
 148 _PUBLIC_ PyObject *pytalloc_steal(PyTypeObject *py_type, void *ptr)
 149 {
 150         return pytalloc_steal_ex(py_type, ptr, ptr);
 151 }
 152
 153
 154 /**
 155  * Import an existing talloc pointer into a Python object, leaving the
 156  * original parent, and creating a reference to the object in the python
 157  * object.
 158  *
 159  * We remember the object we hold the reference to (a
 160  * possibly-non-talloc pointer), the existing parent (typically the
 161  * start of the array) and the new referenced parent.  That way we can
 162  * cope with the fact that we will have multiple parents, one per time
 163  * python sees the object.
 164  */
 165 _PUBLIC_ PyObject *pytalloc_reference_ex(PyTypeObject *py_type,
 166                                          TALLOC_CTX *mem_ctx, void *ptr)
 167 {
 168         PyTypeObject *BaseObjectType = pytalloc_GetBaseObjectType();
 169         PyTypeObject *ObjectType = pytalloc_GetObjectType();
 170
 171         if (mem_ctx == NULL) {
 172                 return PyErr_NoMemory();
 173         }
 174
 175         if (PyType_IsSubtype(py_type, BaseObjectType)) {
 176                 pytalloc_BaseObject *ret
 177                         = (pytalloc_BaseObject *)py_type->tp_alloc(py_type, 0);
 178                 ret->talloc_ctx = talloc_new(NULL);
 179                 if (ret->talloc_ctx == NULL) {
 180                         return NULL;
 181                 }
 182                 if (talloc_reference(ret->talloc_ctx, mem_ctx) == NULL) {
 183                         return NULL;
 184                 }
 185                 talloc_set_name_const(ret->talloc_ctx, py_type->tp_name);
 186                 ret->talloc_ptr_ctx = mem_ctx;
 187                 ret->ptr = ptr;
 188                 return (PyObject *)ret;
 189         } else if (PyType_IsSubtype(py_type, ObjectType)) {
 190                 pytalloc_Object *ret
 191                         = (pytalloc_Object *)py_type->tp_alloc(py_type, 0);
 192                 ret->talloc_ctx = talloc_new(NULL);
 193                 if (ret->talloc_ctx == NULL) {
 194                         return NULL;
 195                 }
 196                 if (talloc_reference(ret->talloc_ctx, mem_ctx) == NULL) {
 197                         return NULL;
 198                 }
 199                 talloc_set_name_const(ret->talloc_ctx, py_type->tp_name);
 200                 ret->ptr = ptr;
 201                 return (PyObject *)ret;
 202         } else {
 203                 PyErr_SetString(PyExc_RuntimeError,
 204                                 "pytalloc_reference_ex() called for object type "
 205                                 "not based on talloc");
 206                 return NULL;
 207         }
 208 }
 209
 210 #if PY_MAJOR_VERSION < 3
 211
 212 static void py_cobject_talloc_free(void *ptr)
 213 {
 214         talloc_free(ptr);
 215 }
 216
 217 _PUBLIC_ PyObject *pytalloc_CObject_FromTallocPtr(void *ptr)
 218 {
 219         if (ptr == NULL) {
 220                 Py_RETURN_NONE;
 221         }
 222         return PyCObject_FromVoidPtr(ptr, py_cobject_talloc_free);
 223 }
 224
 225 #endif
 226
 227 /*
 228  * Wrap a generic talloc pointer into a talloc.GenericObject,
 229  * this is a subclass of talloc.BaseObject.
 230  */
 231 _PUBLIC_ PyObject *pytalloc_GenericObject_steal_ex(TALLOC_CTX *mem_ctx, void *ptr)
 232 {
 233         PyTypeObject *tp = pytalloc_GetGenericObjectType();
 234         return pytalloc_steal_ex(tp, mem_ctx, ptr);
 235 }
 236
 237 /*
 238  * Wrap a generic talloc pointer into a talloc.GenericObject,
 239  * this is a subclass of talloc.BaseObject.
 240  */
 241 _PUBLIC_ PyObject *pytalloc_GenericObject_reference_ex(TALLOC_CTX *mem_ctx, void *ptr)
 242 {
 243         PyTypeObject *tp = pytalloc_GetGenericObjectType();
 244         return pytalloc_reference_ex(tp, mem_ctx, ptr);
 245 }
 246
 247 _PUBLIC_ int pytalloc_Check(PyObject *obj)
 248 {
 249         PyTypeObject *tp = pytalloc_GetObjectType();
 250
 251         return PyObject_TypeCheck(obj, tp);
 252 }
 253
 254 _PUBLIC_ int pytalloc_BaseObject_check(PyObject *obj)
 255 {
 256         PyTypeObject *tp = pytalloc_GetBaseObjectType();
 257
 258         return PyObject_TypeCheck(obj, tp);
 259 }
 260
 261 _PUBLIC_ size_t pytalloc_BaseObject_size(void)
 262 {
 263         return sizeof(pytalloc_BaseObject);
 264 }
 265
 266 static void *_pytalloc_get_checked_type(PyObject *py_obj, const char *type_name,
 267                                         bool check_only, const char *function)
 268 {
 269         TALLOC_CTX *mem_ctx;
 270         void *ptr = NULL;
 271         void *type_obj = talloc_check_name(ptr, type_name);
 272
 273         mem_ctx = _pytalloc_get_mem_ctx(py_obj);
 274         ptr = _pytalloc_get_ptr(py_obj);
 275
 276         if (mem_ctx != ptr) {
 277                 if (check_only) {
 278                         return NULL;
 279                 }
 280
 281                 PyErr_Format(PyExc_TypeError, "%s: expected %s, "
 282                              "but the pointer is no talloc pointer, "
 283                              "pytalloc_get_ptr() would get the raw pointer.",
 284                              function, type_name);
 285                 return NULL;
 286         }
 287
 288         type_obj = talloc_check_name(ptr, type_name);
 289         if (type_obj == NULL) {
 290                 const char *name = NULL;
 291
 292                 if (check_only) {
 293                         return NULL;
 294                 }
 295
 296                 name = talloc_get_name(ptr);
 297                 PyErr_Format(PyExc_TypeError, "%s: expected %s, got %s",
 298                              function, type_name, name);
 299                 return NULL;
 300         }
 301
 302         return ptr;
 303 }
 304
 305 _PUBLIC_ int _pytalloc_check_type(PyObject *py_obj, const char *type_name)
 306 {
 307         void *ptr = NULL;
 308
 309         ptr = _pytalloc_get_checked_type(py_obj, type_name,
 310                                          true, /* check_only */
 311                                          "pytalloc_check_type");
 312         if (ptr == NULL) {
 313                 return 0;
 314         }
 315
 316         return 1;
 317 }
 318
 319 _PUBLIC_ void *_pytalloc_get_type(PyObject *py_obj, const char *type_name)
 320 {
 321         return _pytalloc_get_checked_type(py_obj, type_name,
 322                                           false, /* not check_only */
 323                                           "pytalloc_get_type");
 324 }
 325
 326 _PUBLIC_ void *_pytalloc_get_ptr(PyObject *py_obj)
 327 {
 328         if (pytalloc_BaseObject_check(py_obj)) {
 329                 return ((pytalloc_BaseObject *)py_obj)->ptr;
 330         }
 331         if (pytalloc_Check(py_obj)) {
 332                 return ((pytalloc_Object *)py_obj)->ptr;
 333         }
 334         return NULL;
 335 }
 336
 337 _PUBLIC_ TALLOC_CTX *_pytalloc_get_mem_ctx(PyObject *py_obj)
 338 {
 339         if (pytalloc_BaseObject_check(py_obj)) {
 340                 return ((pytalloc_BaseObject *)py_obj)->talloc_ptr_ctx;
 341         }
 342         if (pytalloc_Check(py_obj)) {
 343                 return ((pytalloc_Object *)py_obj)->talloc_ctx;
 344         }
 345         return NULL;
 346 }
 347
 348 _PUBLIC_ int pytalloc_BaseObject_PyType_Ready(PyTypeObject *type)
 349 {
 350         PyTypeObject *talloc_type = pytalloc_GetBaseObjectType();
 351         if (talloc_type == NULL) {
 352                 PyErr_Format(PyExc_TypeError, "pytalloc: unable to get talloc.BaseObject type");
 353                 return -1;
 354         }
 355
 356         type->tp_base = talloc_type;
 357         type->tp_basicsize = pytalloc_BaseObject_size();
 358
 359         return PyType_Ready(type);
 360 }