| 1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 1986-2013 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 | #include "defs.h" |
| 21 | #include "exceptions.h" |
| 22 | #include "breakpoint.h" |
| 23 | #include "target.h" |
| 24 | #include "inferior.h" |
| 25 | #include "annotate.h" |
| 26 | #include "ui-out.h" |
| 27 | #include "gdb_assert.h" |
| 28 | #include "gdb_string.h" |
| 29 | #include "serial.h" |
| 30 | #include "gdbthread.h" |
| 31 | |
| 32 | const struct gdb_exception exception_none = { 0, GDB_NO_ERROR, NULL }; |
| 33 | |
| 34 | /* Possible catcher states. */ |
| 35 | enum catcher_state { |
| 36 | /* Initial state, a new catcher has just been created. */ |
| 37 | CATCHER_CREATED, |
| 38 | /* The catch code is running. */ |
| 39 | CATCHER_RUNNING, |
| 40 | CATCHER_RUNNING_1, |
| 41 | /* The catch code threw an exception. */ |
| 42 | CATCHER_ABORTING |
| 43 | }; |
| 44 | |
| 45 | /* Possible catcher actions. */ |
| 46 | enum catcher_action { |
| 47 | CATCH_ITER, |
| 48 | CATCH_ITER_1, |
| 49 | CATCH_THROWING |
| 50 | }; |
| 51 | |
| 52 | struct catcher |
| 53 | { |
| 54 | enum catcher_state state; |
| 55 | /* Jump buffer pointing back at the exception handler. */ |
| 56 | EXCEPTIONS_SIGJMP_BUF buf; |
| 57 | /* Status buffer belonging to the exception handler. */ |
| 58 | volatile struct gdb_exception *exception; |
| 59 | /* Saved/current state. */ |
| 60 | int mask; |
| 61 | struct cleanup *saved_cleanup_chain; |
| 62 | /* Back link. */ |
| 63 | struct catcher *prev; |
| 64 | }; |
| 65 | |
| 66 | /* Where to go for throw_exception(). */ |
| 67 | static struct catcher *current_catcher; |
| 68 | |
| 69 | /* Return length of current_catcher list. */ |
| 70 | |
| 71 | static int |
| 72 | catcher_list_size (void) |
| 73 | { |
| 74 | int size; |
| 75 | struct catcher *catcher; |
| 76 | |
| 77 | for (size = 0, catcher = current_catcher; |
| 78 | catcher != NULL; |
| 79 | catcher = catcher->prev) |
| 80 | ++size; |
| 81 | |
| 82 | return size; |
| 83 | } |
| 84 | |
| 85 | EXCEPTIONS_SIGJMP_BUF * |
| 86 | exceptions_state_mc_init (volatile struct gdb_exception *exception, |
| 87 | return_mask mask) |
| 88 | { |
| 89 | struct catcher *new_catcher = XZALLOC (struct catcher); |
| 90 | |
| 91 | /* Start with no exception, save it's address. */ |
| 92 | exception->reason = 0; |
| 93 | exception->error = GDB_NO_ERROR; |
| 94 | exception->message = NULL; |
| 95 | new_catcher->exception = exception; |
| 96 | |
| 97 | new_catcher->mask = mask; |
| 98 | |
| 99 | /* Prevent error/quit during FUNC from calling cleanups established |
| 100 | prior to here. */ |
| 101 | new_catcher->saved_cleanup_chain = save_cleanups (); |
| 102 | |
| 103 | /* Push this new catcher on the top. */ |
| 104 | new_catcher->prev = current_catcher; |
| 105 | current_catcher = new_catcher; |
| 106 | new_catcher->state = CATCHER_CREATED; |
| 107 | |
| 108 | return &new_catcher->buf; |
| 109 | } |
| 110 | |
| 111 | static void |
| 112 | catcher_pop (void) |
| 113 | { |
| 114 | struct catcher *old_catcher = current_catcher; |
| 115 | |
| 116 | current_catcher = old_catcher->prev; |
| 117 | |
| 118 | /* Restore the cleanup chain, the error/quit messages, and the uiout |
| 119 | builder, to their original states. */ |
| 120 | |
| 121 | restore_cleanups (old_catcher->saved_cleanup_chain); |
| 122 | |
| 123 | xfree (old_catcher); |
| 124 | } |
| 125 | |
| 126 | /* Catcher state machine. Returns non-zero if the m/c should be run |
| 127 | again, zero if it should abort. */ |
| 128 | |
| 129 | static int |
| 130 | exceptions_state_mc (enum catcher_action action) |
| 131 | { |
| 132 | switch (current_catcher->state) |
| 133 | { |
| 134 | case CATCHER_CREATED: |
| 135 | switch (action) |
| 136 | { |
| 137 | case CATCH_ITER: |
| 138 | /* Allow the code to run the catcher. */ |
| 139 | current_catcher->state = CATCHER_RUNNING; |
| 140 | return 1; |
| 141 | default: |
| 142 | internal_error (__FILE__, __LINE__, _("bad state")); |
| 143 | } |
| 144 | case CATCHER_RUNNING: |
| 145 | switch (action) |
| 146 | { |
| 147 | case CATCH_ITER: |
| 148 | /* No error/quit has occured. Just clean up. */ |
| 149 | catcher_pop (); |
| 150 | return 0; |
| 151 | case CATCH_ITER_1: |
| 152 | current_catcher->state = CATCHER_RUNNING_1; |
| 153 | return 1; |
| 154 | case CATCH_THROWING: |
| 155 | current_catcher->state = CATCHER_ABORTING; |
| 156 | /* See also throw_exception. */ |
| 157 | return 1; |
| 158 | default: |
| 159 | internal_error (__FILE__, __LINE__, _("bad switch")); |
| 160 | } |
| 161 | case CATCHER_RUNNING_1: |
| 162 | switch (action) |
| 163 | { |
| 164 | case CATCH_ITER: |
| 165 | /* The did a "break" from the inner while loop. */ |
| 166 | catcher_pop (); |
| 167 | return 0; |
| 168 | case CATCH_ITER_1: |
| 169 | current_catcher->state = CATCHER_RUNNING; |
| 170 | return 0; |
| 171 | case CATCH_THROWING: |
| 172 | current_catcher->state = CATCHER_ABORTING; |
| 173 | /* See also throw_exception. */ |
| 174 | return 1; |
| 175 | default: |
| 176 | internal_error (__FILE__, __LINE__, _("bad switch")); |
| 177 | } |
| 178 | case CATCHER_ABORTING: |
| 179 | switch (action) |
| 180 | { |
| 181 | case CATCH_ITER: |
| 182 | { |
| 183 | struct gdb_exception exception = *current_catcher->exception; |
| 184 | |
| 185 | if (current_catcher->mask & RETURN_MASK (exception.reason)) |
| 186 | { |
| 187 | /* Exit normally if this catcher can handle this |
| 188 | exception. The caller analyses the func return |
| 189 | values. */ |
| 190 | catcher_pop (); |
| 191 | return 0; |
| 192 | } |
| 193 | /* The caller didn't request that the event be caught, |
| 194 | relay the event to the next containing |
| 195 | catch_errors(). */ |
| 196 | catcher_pop (); |
| 197 | throw_exception (exception); |
| 198 | } |
| 199 | default: |
| 200 | internal_error (__FILE__, __LINE__, _("bad state")); |
| 201 | } |
| 202 | default: |
| 203 | internal_error (__FILE__, __LINE__, _("bad switch")); |
| 204 | } |
| 205 | } |
| 206 | |
| 207 | int |
| 208 | exceptions_state_mc_action_iter (void) |
| 209 | { |
| 210 | return exceptions_state_mc (CATCH_ITER); |
| 211 | } |
| 212 | |
| 213 | int |
| 214 | exceptions_state_mc_action_iter_1 (void) |
| 215 | { |
| 216 | return exceptions_state_mc (CATCH_ITER_1); |
| 217 | } |
| 218 | |
| 219 | /* Return EXCEPTION to the nearest containing catch_errors(). */ |
| 220 | |
| 221 | void |
| 222 | throw_exception (struct gdb_exception exception) |
| 223 | { |
| 224 | clear_quit_flag (); |
| 225 | immediate_quit = 0; |
| 226 | |
| 227 | do_cleanups (all_cleanups ()); |
| 228 | |
| 229 | /* Jump to the containing catch_errors() call, communicating REASON |
| 230 | to that call via setjmp's return value. Note that REASON can't |
| 231 | be zero, by definition in defs.h. */ |
| 232 | exceptions_state_mc (CATCH_THROWING); |
| 233 | *current_catcher->exception = exception; |
| 234 | EXCEPTIONS_SIGLONGJMP (current_catcher->buf, exception.reason); |
| 235 | } |
| 236 | |
| 237 | static void |
| 238 | print_flush (void) |
| 239 | { |
| 240 | struct serial *gdb_stdout_serial; |
| 241 | |
| 242 | if (deprecated_error_begin_hook) |
| 243 | deprecated_error_begin_hook (); |
| 244 | target_terminal_ours (); |
| 245 | |
| 246 | /* We want all output to appear now, before we print the error. We |
| 247 | have 3 levels of buffering we have to flush (it's possible that |
| 248 | some of these should be changed to flush the lower-level ones |
| 249 | too): */ |
| 250 | |
| 251 | /* 1. The _filtered buffer. */ |
| 252 | wrap_here (""); |
| 253 | |
| 254 | /* 2. The stdio buffer. */ |
| 255 | gdb_flush (gdb_stdout); |
| 256 | gdb_flush (gdb_stderr); |
| 257 | |
| 258 | /* 3. The system-level buffer. */ |
| 259 | gdb_stdout_serial = serial_fdopen (1); |
| 260 | if (gdb_stdout_serial) |
| 261 | { |
| 262 | serial_drain_output (gdb_stdout_serial); |
| 263 | serial_un_fdopen (gdb_stdout_serial); |
| 264 | } |
| 265 | |
| 266 | annotate_error_begin (); |
| 267 | } |
| 268 | |
| 269 | static void |
| 270 | print_exception (struct ui_file *file, struct gdb_exception e) |
| 271 | { |
| 272 | /* KLUGE: cagney/2005-01-13: Write the string out one line at a time |
| 273 | as that way the MI's behavior is preserved. */ |
| 274 | const char *start; |
| 275 | const char *end; |
| 276 | |
| 277 | for (start = e.message; start != NULL; start = end) |
| 278 | { |
| 279 | end = strchr (start, '\n'); |
| 280 | if (end == NULL) |
| 281 | fputs_filtered (start, file); |
| 282 | else |
| 283 | { |
| 284 | end++; |
| 285 | ui_file_write (file, start, end - start); |
| 286 | } |
| 287 | } |
| 288 | fprintf_filtered (file, "\n"); |
| 289 | |
| 290 | /* Now append the annotation. */ |
| 291 | switch (e.reason) |
| 292 | { |
| 293 | case RETURN_QUIT: |
| 294 | annotate_quit (); |
| 295 | break; |
| 296 | case RETURN_ERROR: |
| 297 | /* Assume that these are all errors. */ |
| 298 | annotate_error (); |
| 299 | break; |
| 300 | default: |
| 301 | internal_error (__FILE__, __LINE__, _("Bad switch.")); |
| 302 | } |
| 303 | } |
| 304 | |
| 305 | void |
| 306 | exception_print (struct ui_file *file, struct gdb_exception e) |
| 307 | { |
| 308 | if (e.reason < 0 && e.message != NULL) |
| 309 | { |
| 310 | print_flush (); |
| 311 | print_exception (file, e); |
| 312 | } |
| 313 | } |
| 314 | |
| 315 | void |
| 316 | exception_fprintf (struct ui_file *file, struct gdb_exception e, |
| 317 | const char *prefix, ...) |
| 318 | { |
| 319 | if (e.reason < 0 && e.message != NULL) |
| 320 | { |
| 321 | va_list args; |
| 322 | |
| 323 | print_flush (); |
| 324 | |
| 325 | /* Print the prefix. */ |
| 326 | va_start (args, prefix); |
| 327 | vfprintf_filtered (file, prefix, args); |
| 328 | va_end (args); |
| 329 | |
| 330 | print_exception (file, e); |
| 331 | } |
| 332 | } |
| 333 | |
| 334 | static void |
| 335 | print_any_exception (struct ui_file *file, const char *prefix, |
| 336 | struct gdb_exception e) |
| 337 | { |
| 338 | if (e.reason < 0 && e.message != NULL) |
| 339 | { |
| 340 | target_terminal_ours (); |
| 341 | wrap_here (""); /* Force out any buffered output. */ |
| 342 | gdb_flush (gdb_stdout); |
| 343 | annotate_error_begin (); |
| 344 | |
| 345 | /* Print the prefix. */ |
| 346 | if (prefix != NULL && prefix[0] != '\0') |
| 347 | fputs_filtered (prefix, file); |
| 348 | print_exception (file, e); |
| 349 | } |
| 350 | } |
| 351 | |
| 352 | /* A stack of exception messages. |
| 353 | This is needed to handle nested calls to throw_it: we don't want to |
| 354 | xfree space for a message before it's used. |
| 355 | This can happen if we throw an exception during a cleanup: |
| 356 | An outer TRY_CATCH may have an exception message it wants to print, |
| 357 | but while doing cleanups further calls to throw_it are made. |
| 358 | |
| 359 | This is indexed by the size of the current_catcher list. |
| 360 | It is a dynamically allocated array so that we don't care how deeply |
| 361 | GDB nests its TRY_CATCHs. */ |
| 362 | static char **exception_messages; |
| 363 | |
| 364 | /* The number of currently allocated entries in exception_messages. */ |
| 365 | static int exception_messages_size; |
| 366 | |
| 367 | static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0) |
| 368 | throw_it (enum return_reason reason, enum errors error, const char *fmt, |
| 369 | va_list ap) |
| 370 | { |
| 371 | struct gdb_exception e; |
| 372 | char *new_message; |
| 373 | int depth = catcher_list_size (); |
| 374 | |
| 375 | gdb_assert (depth > 0); |
| 376 | |
| 377 | /* Note: The new message may use an old message's text. */ |
| 378 | new_message = xstrvprintf (fmt, ap); |
| 379 | |
| 380 | if (depth > exception_messages_size) |
| 381 | { |
| 382 | int old_size = exception_messages_size; |
| 383 | |
| 384 | exception_messages_size = depth + 10; |
| 385 | exception_messages = (char **) xrealloc (exception_messages, |
| 386 | exception_messages_size |
| 387 | * sizeof (char *)); |
| 388 | memset (exception_messages + old_size, 0, |
| 389 | (exception_messages_size - old_size) * sizeof (char *)); |
| 390 | } |
| 391 | |
| 392 | xfree (exception_messages[depth - 1]); |
| 393 | exception_messages[depth - 1] = new_message; |
| 394 | |
| 395 | /* Create the exception. */ |
| 396 | e.reason = reason; |
| 397 | e.error = error; |
| 398 | e.message = new_message; |
| 399 | |
| 400 | /* Throw the exception. */ |
| 401 | throw_exception (e); |
| 402 | } |
| 403 | |
| 404 | void |
| 405 | throw_verror (enum errors error, const char *fmt, va_list ap) |
| 406 | { |
| 407 | throw_it (RETURN_ERROR, error, fmt, ap); |
| 408 | } |
| 409 | |
| 410 | void |
| 411 | throw_vfatal (const char *fmt, va_list ap) |
| 412 | { |
| 413 | throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap); |
| 414 | } |
| 415 | |
| 416 | void |
| 417 | throw_error (enum errors error, const char *fmt, ...) |
| 418 | { |
| 419 | va_list args; |
| 420 | |
| 421 | va_start (args, fmt); |
| 422 | throw_it (RETURN_ERROR, error, fmt, args); |
| 423 | va_end (args); |
| 424 | } |
| 425 | |
| 426 | /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception |
| 427 | handler. If an exception (enum return_reason) is thrown using |
| 428 | throw_exception() than all cleanups installed since |
| 429 | catch_exceptions() was entered are invoked, the (-ve) exception |
| 430 | value is then returned by catch_exceptions. If FUNC() returns |
| 431 | normally (with a positive or zero return value) then that value is |
| 432 | returned by catch_exceptions(). It is an internal_error() for |
| 433 | FUNC() to return a negative value. |
| 434 | |
| 435 | See exceptions.h for further usage details. |
| 436 | |
| 437 | Must not be called with immediate_quit in effect (bad things might |
| 438 | happen, say we got a signal in the middle of a memcpy to quit_return). |
| 439 | This is an OK restriction; with very few exceptions immediate_quit can |
| 440 | be replaced by judicious use of QUIT. */ |
| 441 | |
| 442 | /* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with |
| 443 | error() et al. could maintain a set of flags that indicate the |
| 444 | current state of each of the longjmp buffers. This would give the |
| 445 | longjmp code the chance to detect a longjmp botch (before it gets |
| 446 | to longjmperror()). Prior to 1999-11-05 this wasn't possible as |
| 447 | code also randomly used a SET_TOP_LEVEL macro that directly |
| 448 | initialized the longjmp buffers. */ |
| 449 | |
| 450 | int |
| 451 | catch_exceptions (struct ui_out *uiout, |
| 452 | catch_exceptions_ftype *func, |
| 453 | void *func_args, |
| 454 | return_mask mask) |
| 455 | { |
| 456 | return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask); |
| 457 | } |
| 458 | |
| 459 | int |
| 460 | catch_exceptions_with_msg (struct ui_out *func_uiout, |
| 461 | catch_exceptions_ftype *func, |
| 462 | void *func_args, |
| 463 | char **gdberrmsg, |
| 464 | return_mask mask) |
| 465 | { |
| 466 | volatile struct gdb_exception exception; |
| 467 | volatile int val = 0; |
| 468 | struct ui_out *saved_uiout; |
| 469 | |
| 470 | /* Save and override the global ``struct ui_out'' builder. */ |
| 471 | saved_uiout = current_uiout; |
| 472 | current_uiout = func_uiout; |
| 473 | |
| 474 | TRY_CATCH (exception, RETURN_MASK_ALL) |
| 475 | { |
| 476 | val = (*func) (current_uiout, func_args); |
| 477 | } |
| 478 | |
| 479 | /* Restore the global builder. */ |
| 480 | current_uiout = saved_uiout; |
| 481 | |
| 482 | if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0) |
| 483 | { |
| 484 | /* The caller didn't request that the event be caught. |
| 485 | Rethrow. */ |
| 486 | throw_exception (exception); |
| 487 | } |
| 488 | |
| 489 | print_any_exception (gdb_stderr, NULL, exception); |
| 490 | gdb_assert (val >= 0); |
| 491 | gdb_assert (exception.reason <= 0); |
| 492 | if (exception.reason < 0) |
| 493 | { |
| 494 | /* If caller wants a copy of the low-level error message, make |
| 495 | one. This is used in the case of a silent error whereby the |
| 496 | caller may optionally want to issue the message. */ |
| 497 | if (gdberrmsg != NULL) |
| 498 | { |
| 499 | if (exception.message != NULL) |
| 500 | *gdberrmsg = xstrdup (exception.message); |
| 501 | else |
| 502 | *gdberrmsg = NULL; |
| 503 | } |
| 504 | return exception.reason; |
| 505 | } |
| 506 | return val; |
| 507 | } |
| 508 | |
| 509 | /* This function is superseded by catch_exceptions(). */ |
| 510 | |
| 511 | int |
| 512 | catch_errors (catch_errors_ftype *func, void *func_args, char *errstring, |
| 513 | return_mask mask) |
| 514 | { |
| 515 | volatile int val = 0; |
| 516 | volatile struct gdb_exception exception; |
| 517 | struct ui_out *saved_uiout; |
| 518 | |
| 519 | /* Save the global ``struct ui_out'' builder. */ |
| 520 | saved_uiout = current_uiout; |
| 521 | |
| 522 | TRY_CATCH (exception, RETURN_MASK_ALL) |
| 523 | { |
| 524 | val = func (func_args); |
| 525 | } |
| 526 | |
| 527 | /* Restore the global builder. */ |
| 528 | current_uiout = saved_uiout; |
| 529 | |
| 530 | if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0) |
| 531 | { |
| 532 | /* The caller didn't request that the event be caught. |
| 533 | Rethrow. */ |
| 534 | throw_exception (exception); |
| 535 | } |
| 536 | |
| 537 | print_any_exception (gdb_stderr, errstring, exception); |
| 538 | if (exception.reason != 0) |
| 539 | return 0; |
| 540 | return val; |
| 541 | } |
| 542 | |
| 543 | int |
| 544 | catch_command_errors (catch_command_errors_ftype *command, |
| 545 | char *arg, int from_tty, return_mask mask) |
| 546 | { |
| 547 | volatile struct gdb_exception e; |
| 548 | |
| 549 | TRY_CATCH (e, mask) |
| 550 | { |
| 551 | command (arg, from_tty); |
| 552 | } |
| 553 | print_any_exception (gdb_stderr, NULL, e); |
| 554 | if (e.reason < 0) |
| 555 | return 0; |
| 556 | return 1; |
| 557 | } |
| 558 | |
| 559 | int |
| 560 | catch_command_errors_const (catch_command_errors_const_ftype *command, |
| 561 | const char *arg, int from_tty, return_mask mask) |
| 562 | { |
| 563 | volatile struct gdb_exception e; |
| 564 | |
| 565 | TRY_CATCH (e, mask) |
| 566 | { |
| 567 | command (arg, from_tty); |
| 568 | } |
| 569 | print_any_exception (gdb_stderr, NULL, e); |
| 570 | if (e.reason < 0) |
| 571 | return 0; |
| 572 | return 1; |
| 573 | } |