| 1 | /* Python interface to finish breakpoints |
| 2 | |
| 3 | Copyright (C) 2011-2017 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "python-internal.h" |
| 24 | #include "breakpoint.h" |
| 25 | #include "frame.h" |
| 26 | #include "gdbthread.h" |
| 27 | #include "arch-utils.h" |
| 28 | #include "language.h" |
| 29 | #include "observer.h" |
| 30 | #include "inferior.h" |
| 31 | #include "block.h" |
| 32 | #include "location.h" |
| 33 | #include "py-ref.h" |
| 34 | |
| 35 | /* Function that is called when a Python finish bp is found out of scope. */ |
| 36 | static char * const outofscope_func = "out_of_scope"; |
| 37 | |
| 38 | /* struct implementing the gdb.FinishBreakpoint object by extending |
| 39 | the gdb.Breakpoint class. */ |
| 40 | struct finish_breakpoint_object |
| 41 | { |
| 42 | /* gdb.Breakpoint base class. */ |
| 43 | gdbpy_breakpoint_object py_bp; |
| 44 | /* gdb.Type object of the value return by the breakpointed function. |
| 45 | May be NULL if no debug information was available or return type |
| 46 | was VOID. */ |
| 47 | PyObject *return_type; |
| 48 | /* gdb.Value object of the function finished by this breakpoint. Will be |
| 49 | NULL if return_type is NULL. */ |
| 50 | PyObject *function_value; |
| 51 | /* When stopped at this FinishBreakpoint, gdb.Value object returned by |
| 52 | the function; Py_None if the value is not computable; NULL if GDB is |
| 53 | not stopped at a FinishBreakpoint. */ |
| 54 | PyObject *return_value; |
| 55 | }; |
| 56 | |
| 57 | extern PyTypeObject finish_breakpoint_object_type |
| 58 | CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("finish_breakpoint_object"); |
| 59 | |
| 60 | /* Python function to get the 'return_value' attribute of |
| 61 | FinishBreakpoint. */ |
| 62 | |
| 63 | static PyObject * |
| 64 | bpfinishpy_get_returnvalue (PyObject *self, void *closure) |
| 65 | { |
| 66 | struct finish_breakpoint_object *self_finishbp = |
| 67 | (struct finish_breakpoint_object *) self; |
| 68 | |
| 69 | if (!self_finishbp->return_value) |
| 70 | Py_RETURN_NONE; |
| 71 | |
| 72 | Py_INCREF (self_finishbp->return_value); |
| 73 | return self_finishbp->return_value; |
| 74 | } |
| 75 | |
| 76 | /* Deallocate FinishBreakpoint object. */ |
| 77 | |
| 78 | static void |
| 79 | bpfinishpy_dealloc (PyObject *self) |
| 80 | { |
| 81 | struct finish_breakpoint_object *self_bpfinish = |
| 82 | (struct finish_breakpoint_object *) self; |
| 83 | |
| 84 | Py_XDECREF (self_bpfinish->function_value); |
| 85 | Py_XDECREF (self_bpfinish->return_type); |
| 86 | Py_XDECREF (self_bpfinish->return_value); |
| 87 | } |
| 88 | |
| 89 | /* Triggered when gdbpy_should_stop is about to execute the `stop' callback |
| 90 | of the gdb.FinishBreakpoint object BP_OBJ. Will compute and cache the |
| 91 | `return_value', if possible. */ |
| 92 | |
| 93 | void |
| 94 | bpfinishpy_pre_stop_hook (struct gdbpy_breakpoint_object *bp_obj) |
| 95 | { |
| 96 | struct finish_breakpoint_object *self_finishbp = |
| 97 | (struct finish_breakpoint_object *) bp_obj; |
| 98 | |
| 99 | /* Can compute return_value only once. */ |
| 100 | gdb_assert (!self_finishbp->return_value); |
| 101 | |
| 102 | if (!self_finishbp->return_type) |
| 103 | return; |
| 104 | |
| 105 | TRY |
| 106 | { |
| 107 | struct value *function = |
| 108 | value_object_to_value (self_finishbp->function_value); |
| 109 | struct type *value_type = |
| 110 | type_object_to_type (self_finishbp->return_type); |
| 111 | struct value *ret = get_return_value (function, value_type); |
| 112 | |
| 113 | if (ret) |
| 114 | { |
| 115 | self_finishbp->return_value = value_to_value_object (ret); |
| 116 | if (!self_finishbp->return_value) |
| 117 | gdbpy_print_stack (); |
| 118 | } |
| 119 | else |
| 120 | { |
| 121 | Py_INCREF (Py_None); |
| 122 | self_finishbp->return_value = Py_None; |
| 123 | } |
| 124 | } |
| 125 | CATCH (except, RETURN_MASK_ALL) |
| 126 | { |
| 127 | gdbpy_convert_exception (except); |
| 128 | gdbpy_print_stack (); |
| 129 | } |
| 130 | END_CATCH |
| 131 | } |
| 132 | |
| 133 | /* Triggered when gdbpy_should_stop has triggered the `stop' callback |
| 134 | of the gdb.FinishBreakpoint object BP_OBJ. */ |
| 135 | |
| 136 | void |
| 137 | bpfinishpy_post_stop_hook (struct gdbpy_breakpoint_object *bp_obj) |
| 138 | { |
| 139 | |
| 140 | TRY |
| 141 | { |
| 142 | /* Can't delete it here, but it will be removed at the next stop. */ |
| 143 | disable_breakpoint (bp_obj->bp); |
| 144 | gdb_assert (bp_obj->bp->disposition == disp_del); |
| 145 | } |
| 146 | CATCH (except, RETURN_MASK_ALL) |
| 147 | { |
| 148 | gdbpy_convert_exception (except); |
| 149 | gdbpy_print_stack (); |
| 150 | } |
| 151 | END_CATCH |
| 152 | } |
| 153 | |
| 154 | /* Python function to create a new breakpoint. */ |
| 155 | |
| 156 | static int |
| 157 | bpfinishpy_init (PyObject *self, PyObject *args, PyObject *kwargs) |
| 158 | { |
| 159 | static char *keywords[] = { "frame", "internal", NULL }; |
| 160 | struct finish_breakpoint_object *self_bpfinish = |
| 161 | (struct finish_breakpoint_object *) self; |
| 162 | PyObject *frame_obj = NULL; |
| 163 | int thread; |
| 164 | struct frame_info *frame = NULL; /* init for gcc -Wall */ |
| 165 | struct frame_info *prev_frame = NULL; |
| 166 | struct frame_id frame_id; |
| 167 | PyObject *internal = NULL; |
| 168 | int internal_bp = 0; |
| 169 | CORE_ADDR pc; |
| 170 | struct symbol *function; |
| 171 | |
| 172 | if (!PyArg_ParseTupleAndKeywords (args, kwargs, "|OO", keywords, |
| 173 | &frame_obj, &internal)) |
| 174 | return -1; |
| 175 | |
| 176 | TRY |
| 177 | { |
| 178 | /* Default frame to newest frame if necessary. */ |
| 179 | if (frame_obj == NULL) |
| 180 | frame = get_current_frame (); |
| 181 | else |
| 182 | frame = frame_object_to_frame_info (frame_obj); |
| 183 | |
| 184 | if (frame == NULL) |
| 185 | { |
| 186 | PyErr_SetString (PyExc_ValueError, |
| 187 | _("Invalid ID for the `frame' object.")); |
| 188 | } |
| 189 | else |
| 190 | { |
| 191 | prev_frame = get_prev_frame (frame); |
| 192 | if (prev_frame == 0) |
| 193 | { |
| 194 | PyErr_SetString (PyExc_ValueError, |
| 195 | _("\"FinishBreakpoint\" not " |
| 196 | "meaningful in the outermost " |
| 197 | "frame.")); |
| 198 | } |
| 199 | else if (get_frame_type (prev_frame) == DUMMY_FRAME) |
| 200 | { |
| 201 | PyErr_SetString (PyExc_ValueError, |
| 202 | _("\"FinishBreakpoint\" cannot " |
| 203 | "be set on a dummy frame.")); |
| 204 | } |
| 205 | else |
| 206 | { |
| 207 | frame_id = get_frame_id (prev_frame); |
| 208 | if (frame_id_eq (frame_id, null_frame_id)) |
| 209 | PyErr_SetString (PyExc_ValueError, |
| 210 | _("Invalid ID for the `frame' object.")); |
| 211 | } |
| 212 | } |
| 213 | } |
| 214 | CATCH (except, RETURN_MASK_ALL) |
| 215 | { |
| 216 | gdbpy_convert_exception (except); |
| 217 | return -1; |
| 218 | } |
| 219 | END_CATCH |
| 220 | |
| 221 | if (PyErr_Occurred ()) |
| 222 | return -1; |
| 223 | |
| 224 | thread = ptid_to_global_thread_id (inferior_ptid); |
| 225 | if (thread == 0) |
| 226 | { |
| 227 | PyErr_SetString (PyExc_ValueError, |
| 228 | _("No thread currently selected.")); |
| 229 | return -1; |
| 230 | } |
| 231 | |
| 232 | if (internal) |
| 233 | { |
| 234 | internal_bp = PyObject_IsTrue (internal); |
| 235 | if (internal_bp == -1) |
| 236 | { |
| 237 | PyErr_SetString (PyExc_ValueError, |
| 238 | _("The value of `internal' must be a boolean.")); |
| 239 | return -1; |
| 240 | } |
| 241 | } |
| 242 | |
| 243 | /* Find the function we will return from. */ |
| 244 | self_bpfinish->return_type = NULL; |
| 245 | self_bpfinish->function_value = NULL; |
| 246 | |
| 247 | TRY |
| 248 | { |
| 249 | if (get_frame_pc_if_available (frame, &pc)) |
| 250 | { |
| 251 | function = find_pc_function (pc); |
| 252 | if (function != NULL) |
| 253 | { |
| 254 | struct type *ret_type = |
| 255 | TYPE_TARGET_TYPE (SYMBOL_TYPE (function)); |
| 256 | |
| 257 | /* Remember only non-void return types. */ |
| 258 | if (TYPE_CODE (ret_type) != TYPE_CODE_VOID) |
| 259 | { |
| 260 | struct value *func_value; |
| 261 | |
| 262 | /* Ignore Python errors at this stage. */ |
| 263 | self_bpfinish->return_type = type_to_type_object (ret_type); |
| 264 | PyErr_Clear (); |
| 265 | func_value = read_var_value (function, NULL, frame); |
| 266 | self_bpfinish->function_value = |
| 267 | value_to_value_object (func_value); |
| 268 | PyErr_Clear (); |
| 269 | } |
| 270 | } |
| 271 | } |
| 272 | } |
| 273 | CATCH (except, RETURN_MASK_ALL) |
| 274 | { |
| 275 | /* Just swallow. Either the return type or the function value |
| 276 | remain NULL. */ |
| 277 | } |
| 278 | END_CATCH |
| 279 | |
| 280 | if (self_bpfinish->return_type == NULL || self_bpfinish->function_value == NULL) |
| 281 | { |
| 282 | /* Won't be able to compute return value. */ |
| 283 | Py_XDECREF (self_bpfinish->return_type); |
| 284 | Py_XDECREF (self_bpfinish->function_value); |
| 285 | |
| 286 | self_bpfinish->return_type = NULL; |
| 287 | self_bpfinish->function_value = NULL; |
| 288 | } |
| 289 | |
| 290 | bppy_pending_object = &self_bpfinish->py_bp; |
| 291 | bppy_pending_object->number = -1; |
| 292 | bppy_pending_object->bp = NULL; |
| 293 | |
| 294 | TRY |
| 295 | { |
| 296 | struct event_location *location; |
| 297 | struct cleanup *back_to; |
| 298 | |
| 299 | /* Set a breakpoint on the return address. */ |
| 300 | location = new_address_location (get_frame_pc (prev_frame), NULL, 0); |
| 301 | back_to = make_cleanup_delete_event_location (location); |
| 302 | create_breakpoint (python_gdbarch, |
| 303 | location, NULL, thread, NULL, |
| 304 | 0, |
| 305 | 1 /*temp_flag*/, |
| 306 | bp_breakpoint, |
| 307 | 0, |
| 308 | AUTO_BOOLEAN_TRUE, |
| 309 | &bkpt_breakpoint_ops, |
| 310 | 0, 1, internal_bp, 0); |
| 311 | do_cleanups (back_to); |
| 312 | } |
| 313 | CATCH (except, RETURN_MASK_ALL) |
| 314 | { |
| 315 | GDB_PY_SET_HANDLE_EXCEPTION (except); |
| 316 | } |
| 317 | END_CATCH |
| 318 | |
| 319 | self_bpfinish->py_bp.bp->frame_id = frame_id; |
| 320 | self_bpfinish->py_bp.is_finish_bp = 1; |
| 321 | |
| 322 | /* Bind the breakpoint with the current program space. */ |
| 323 | self_bpfinish->py_bp.bp->pspace = current_program_space; |
| 324 | |
| 325 | return 0; |
| 326 | } |
| 327 | |
| 328 | /* Called when GDB notices that the finish breakpoint BP_OBJ is out of |
| 329 | the current callstack. Triggers the method OUT_OF_SCOPE if implemented, |
| 330 | then delete the breakpoint. */ |
| 331 | |
| 332 | static void |
| 333 | bpfinishpy_out_of_scope (struct finish_breakpoint_object *bpfinish_obj) |
| 334 | { |
| 335 | gdbpy_breakpoint_object *bp_obj = (gdbpy_breakpoint_object *) bpfinish_obj; |
| 336 | PyObject *py_obj = (PyObject *) bp_obj; |
| 337 | |
| 338 | if (bpfinish_obj->py_bp.bp->enable_state == bp_enabled |
| 339 | && PyObject_HasAttrString (py_obj, outofscope_func)) |
| 340 | { |
| 341 | gdbpy_ref<> meth_result (PyObject_CallMethod (py_obj, outofscope_func, |
| 342 | NULL)); |
| 343 | if (meth_result == NULL) |
| 344 | gdbpy_print_stack (); |
| 345 | } |
| 346 | |
| 347 | delete_breakpoint (bpfinish_obj->py_bp.bp); |
| 348 | } |
| 349 | |
| 350 | /* Callback for `bpfinishpy_detect_out_scope'. Triggers Python's |
| 351 | `B->out_of_scope' function if B is a FinishBreakpoint out of its scope. */ |
| 352 | |
| 353 | static int |
| 354 | bpfinishpy_detect_out_scope_cb (struct breakpoint *b, void *args) |
| 355 | { |
| 356 | struct breakpoint *bp_stopped = (struct breakpoint *) args; |
| 357 | PyObject *py_bp = (PyObject *) b->py_bp_object; |
| 358 | |
| 359 | /* Trigger out_of_scope if this is a FinishBreakpoint and its frame is |
| 360 | not anymore in the current callstack. */ |
| 361 | if (py_bp != NULL && b->py_bp_object->is_finish_bp) |
| 362 | { |
| 363 | struct finish_breakpoint_object *finish_bp = |
| 364 | (struct finish_breakpoint_object *) py_bp; |
| 365 | |
| 366 | /* Check scope if not currently stopped at the FinishBreakpoint. */ |
| 367 | if (b != bp_stopped) |
| 368 | { |
| 369 | TRY |
| 370 | { |
| 371 | if (b->pspace == current_inferior ()->pspace |
| 372 | && (!target_has_registers |
| 373 | || frame_find_by_id (b->frame_id) == NULL)) |
| 374 | bpfinishpy_out_of_scope (finish_bp); |
| 375 | } |
| 376 | CATCH (except, RETURN_MASK_ALL) |
| 377 | { |
| 378 | gdbpy_convert_exception (except); |
| 379 | gdbpy_print_stack (); |
| 380 | } |
| 381 | END_CATCH |
| 382 | } |
| 383 | } |
| 384 | |
| 385 | return 0; |
| 386 | } |
| 387 | |
| 388 | /* Attached to `stop' notifications, check if the execution has run |
| 389 | out of the scope of any FinishBreakpoint before it has been hit. */ |
| 390 | |
| 391 | static void |
| 392 | bpfinishpy_handle_stop (struct bpstats *bs, int print_frame) |
| 393 | { |
| 394 | gdbpy_enter enter_py (get_current_arch (), current_language); |
| 395 | |
| 396 | iterate_over_breakpoints (bpfinishpy_detect_out_scope_cb, |
| 397 | bs == NULL ? NULL : bs->breakpoint_at); |
| 398 | } |
| 399 | |
| 400 | /* Attached to `exit' notifications, triggers all the necessary out of |
| 401 | scope notifications. */ |
| 402 | |
| 403 | static void |
| 404 | bpfinishpy_handle_exit (struct inferior *inf) |
| 405 | { |
| 406 | gdbpy_enter enter_py (target_gdbarch (), current_language); |
| 407 | |
| 408 | iterate_over_breakpoints (bpfinishpy_detect_out_scope_cb, NULL); |
| 409 | } |
| 410 | |
| 411 | /* Initialize the Python finish breakpoint code. */ |
| 412 | |
| 413 | int |
| 414 | gdbpy_initialize_finishbreakpoints (void) |
| 415 | { |
| 416 | if (PyType_Ready (&finish_breakpoint_object_type) < 0) |
| 417 | return -1; |
| 418 | |
| 419 | if (gdb_pymodule_addobject (gdb_module, "FinishBreakpoint", |
| 420 | (PyObject *) &finish_breakpoint_object_type) < 0) |
| 421 | return -1; |
| 422 | |
| 423 | observer_attach_normal_stop (bpfinishpy_handle_stop); |
| 424 | observer_attach_inferior_exit (bpfinishpy_handle_exit); |
| 425 | |
| 426 | return 0; |
| 427 | } |
| 428 | |
| 429 | static PyGetSetDef finish_breakpoint_object_getset[] = { |
| 430 | { "return_value", bpfinishpy_get_returnvalue, NULL, |
| 431 | "gdb.Value object representing the return value, if any. \ |
| 432 | None otherwise.", NULL }, |
| 433 | { NULL } /* Sentinel. */ |
| 434 | }; |
| 435 | |
| 436 | PyTypeObject finish_breakpoint_object_type = |
| 437 | { |
| 438 | PyVarObject_HEAD_INIT (NULL, 0) |
| 439 | "gdb.FinishBreakpoint", /*tp_name*/ |
| 440 | sizeof (struct finish_breakpoint_object), /*tp_basicsize*/ |
| 441 | 0, /*tp_itemsize*/ |
| 442 | bpfinishpy_dealloc, /*tp_dealloc*/ |
| 443 | 0, /*tp_print*/ |
| 444 | 0, /*tp_getattr*/ |
| 445 | 0, /*tp_setattr*/ |
| 446 | 0, /*tp_compare*/ |
| 447 | 0, /*tp_repr*/ |
| 448 | 0, /*tp_as_number*/ |
| 449 | 0, /*tp_as_sequence*/ |
| 450 | 0, /*tp_as_mapping*/ |
| 451 | 0, /*tp_hash */ |
| 452 | 0, /*tp_call*/ |
| 453 | 0, /*tp_str*/ |
| 454 | 0, /*tp_getattro*/ |
| 455 | 0, /*tp_setattro */ |
| 456 | 0, /*tp_as_buffer*/ |
| 457 | Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/ |
| 458 | "GDB finish breakpoint object", /* tp_doc */ |
| 459 | 0, /* tp_traverse */ |
| 460 | 0, /* tp_clear */ |
| 461 | 0, /* tp_richcompare */ |
| 462 | 0, /* tp_weaklistoffset */ |
| 463 | 0, /* tp_iter */ |
| 464 | 0, /* tp_iternext */ |
| 465 | 0, /* tp_methods */ |
| 466 | 0, /* tp_members */ |
| 467 | finish_breakpoint_object_getset,/* tp_getset */ |
| 468 | &breakpoint_object_type, /* tp_base */ |
| 469 | 0, /* tp_dict */ |
| 470 | 0, /* tp_descr_get */ |
| 471 | 0, /* tp_descr_set */ |
| 472 | 0, /* tp_dictoffset */ |
| 473 | bpfinishpy_init, /* tp_init */ |
| 474 | 0, /* tp_alloc */ |
| 475 | 0 /* tp_new */ |
| 476 | }; |