| 1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, |
| 4 | 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free |
| 5 | Software Foundation, Inc. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 2 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program; if not, write to the Free Software |
| 21 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 22 | Boston, MA 02111-1307, USA. */ |
| 23 | |
| 24 | #include "defs.h" |
| 25 | #include "exceptions.h" |
| 26 | #include "breakpoint.h" |
| 27 | #include "target.h" |
| 28 | #include "inferior.h" |
| 29 | #include "annotate.h" |
| 30 | #include "ui-out.h" |
| 31 | #include "gdb_assert.h" |
| 32 | #include "gdb_string.h" |
| 33 | #include "serial.h" |
| 34 | |
| 35 | const struct gdb_exception exception_none = { 0, NO_ERROR, NULL }; |
| 36 | |
| 37 | /* Possible catcher states. */ |
| 38 | enum catcher_state { |
| 39 | /* Initial state, a new catcher has just been created. */ |
| 40 | CATCHER_CREATED, |
| 41 | /* The catch code is running. */ |
| 42 | CATCHER_RUNNING, |
| 43 | CATCHER_RUNNING_1, |
| 44 | /* The catch code threw an exception. */ |
| 45 | CATCHER_ABORTING |
| 46 | }; |
| 47 | |
| 48 | /* Possible catcher actions. */ |
| 49 | enum catcher_action { |
| 50 | CATCH_ITER, |
| 51 | CATCH_ITER_1, |
| 52 | CATCH_THROWING |
| 53 | }; |
| 54 | |
| 55 | struct catcher |
| 56 | { |
| 57 | enum catcher_state state; |
| 58 | /* Jump buffer pointing back at the exception handler. */ |
| 59 | EXCEPTIONS_SIGJMP_BUF buf; |
| 60 | /* Status buffer belonging to the exception handler. */ |
| 61 | volatile struct gdb_exception *exception; |
| 62 | /* Saved/current state. */ |
| 63 | int mask; |
| 64 | struct ui_out *saved_uiout; |
| 65 | struct cleanup *saved_cleanup_chain; |
| 66 | /* Back link. */ |
| 67 | struct catcher *prev; |
| 68 | }; |
| 69 | |
| 70 | /* Where to go for throw_exception(). */ |
| 71 | static struct catcher *current_catcher; |
| 72 | |
| 73 | EXCEPTIONS_SIGJMP_BUF * |
| 74 | exceptions_state_mc_init (struct ui_out *func_uiout, |
| 75 | volatile struct gdb_exception *exception, |
| 76 | return_mask mask) |
| 77 | { |
| 78 | struct catcher *new_catcher = XZALLOC (struct catcher); |
| 79 | |
| 80 | /* Start with no exception, save it's address. */ |
| 81 | exception->reason = 0; |
| 82 | exception->error = NO_ERROR; |
| 83 | exception->message = NULL; |
| 84 | new_catcher->exception = exception; |
| 85 | |
| 86 | new_catcher->mask = mask; |
| 87 | |
| 88 | /* Override the global ``struct ui_out'' builder. */ |
| 89 | new_catcher->saved_uiout = uiout; |
| 90 | uiout = func_uiout; |
| 91 | |
| 92 | /* Prevent error/quit during FUNC from calling cleanups established |
| 93 | prior to here. */ |
| 94 | new_catcher->saved_cleanup_chain = save_cleanups (); |
| 95 | |
| 96 | /* Push this new catcher on the top. */ |
| 97 | new_catcher->prev = current_catcher; |
| 98 | current_catcher = new_catcher; |
| 99 | new_catcher->state = CATCHER_CREATED; |
| 100 | |
| 101 | return &new_catcher->buf; |
| 102 | } |
| 103 | |
| 104 | static void |
| 105 | catcher_pop (void) |
| 106 | { |
| 107 | struct catcher *old_catcher = current_catcher; |
| 108 | current_catcher = old_catcher->prev; |
| 109 | |
| 110 | /* Restore the cleanup chain, the error/quit messages, and the uiout |
| 111 | builder, to their original states. */ |
| 112 | |
| 113 | restore_cleanups (old_catcher->saved_cleanup_chain); |
| 114 | |
| 115 | uiout = old_catcher->saved_uiout; |
| 116 | |
| 117 | xfree (old_catcher); |
| 118 | } |
| 119 | |
| 120 | /* Catcher state machine. Returns non-zero if the m/c should be run |
| 121 | again, zero if it should abort. */ |
| 122 | |
| 123 | static int |
| 124 | exceptions_state_mc (enum catcher_action action) |
| 125 | { |
| 126 | switch (current_catcher->state) |
| 127 | { |
| 128 | case CATCHER_CREATED: |
| 129 | switch (action) |
| 130 | { |
| 131 | case CATCH_ITER: |
| 132 | /* Allow the code to run the catcher. */ |
| 133 | current_catcher->state = CATCHER_RUNNING; |
| 134 | return 1; |
| 135 | default: |
| 136 | internal_error (__FILE__, __LINE__, _("bad state")); |
| 137 | } |
| 138 | case CATCHER_RUNNING: |
| 139 | switch (action) |
| 140 | { |
| 141 | case CATCH_ITER: |
| 142 | /* No error/quit has occured. Just clean up. */ |
| 143 | catcher_pop (); |
| 144 | return 0; |
| 145 | case CATCH_ITER_1: |
| 146 | current_catcher->state = CATCHER_RUNNING_1; |
| 147 | return 1; |
| 148 | case CATCH_THROWING: |
| 149 | current_catcher->state = CATCHER_ABORTING; |
| 150 | /* See also throw_exception. */ |
| 151 | return 1; |
| 152 | default: |
| 153 | internal_error (__FILE__, __LINE__, _("bad switch")); |
| 154 | } |
| 155 | case CATCHER_RUNNING_1: |
| 156 | switch (action) |
| 157 | { |
| 158 | case CATCH_ITER: |
| 159 | /* The did a "break" from the inner while loop. */ |
| 160 | catcher_pop (); |
| 161 | return 0; |
| 162 | case CATCH_ITER_1: |
| 163 | current_catcher->state = CATCHER_RUNNING; |
| 164 | return 0; |
| 165 | case CATCH_THROWING: |
| 166 | current_catcher->state = CATCHER_ABORTING; |
| 167 | /* See also throw_exception. */ |
| 168 | return 1; |
| 169 | default: |
| 170 | internal_error (__FILE__, __LINE__, _("bad switch")); |
| 171 | } |
| 172 | case CATCHER_ABORTING: |
| 173 | switch (action) |
| 174 | { |
| 175 | case CATCH_ITER: |
| 176 | { |
| 177 | struct gdb_exception exception = *current_catcher->exception; |
| 178 | if (current_catcher->mask & RETURN_MASK (exception.reason)) |
| 179 | { |
| 180 | /* Exit normally if this catcher can handle this |
| 181 | exception. The caller analyses the func return |
| 182 | values. */ |
| 183 | catcher_pop (); |
| 184 | return 0; |
| 185 | } |
| 186 | /* The caller didn't request that the event be caught, |
| 187 | relay the event to the next containing |
| 188 | catch_errors(). */ |
| 189 | catcher_pop (); |
| 190 | throw_exception (exception); |
| 191 | } |
| 192 | default: |
| 193 | internal_error (__FILE__, __LINE__, _("bad state")); |
| 194 | } |
| 195 | default: |
| 196 | internal_error (__FILE__, __LINE__, _("bad switch")); |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | int |
| 201 | exceptions_state_mc_action_iter (void) |
| 202 | { |
| 203 | return exceptions_state_mc (CATCH_ITER); |
| 204 | } |
| 205 | |
| 206 | int |
| 207 | exceptions_state_mc_action_iter_1 (void) |
| 208 | { |
| 209 | return exceptions_state_mc (CATCH_ITER_1); |
| 210 | } |
| 211 | |
| 212 | /* Return EXCEPTION to the nearest containing catch_errors(). */ |
| 213 | |
| 214 | NORETURN void |
| 215 | throw_exception (struct gdb_exception exception) |
| 216 | { |
| 217 | quit_flag = 0; |
| 218 | immediate_quit = 0; |
| 219 | |
| 220 | /* Perhaps it would be cleaner to do this via the cleanup chain (not sure |
| 221 | I can think of a reason why that is vital, though). */ |
| 222 | bpstat_clear_actions (stop_bpstat); /* Clear queued breakpoint commands */ |
| 223 | |
| 224 | disable_current_display (); |
| 225 | do_cleanups (ALL_CLEANUPS); |
| 226 | if (target_can_async_p () && !target_executing) |
| 227 | do_exec_cleanups (ALL_CLEANUPS); |
| 228 | if (sync_execution) |
| 229 | do_exec_error_cleanups (ALL_CLEANUPS); |
| 230 | |
| 231 | /* Jump to the containing catch_errors() call, communicating REASON |
| 232 | to that call via setjmp's return value. Note that REASON can't |
| 233 | be zero, by definition in defs.h. */ |
| 234 | exceptions_state_mc (CATCH_THROWING); |
| 235 | *current_catcher->exception = exception; |
| 236 | EXCEPTIONS_SIGLONGJMP (current_catcher->buf, exception.reason); |
| 237 | } |
| 238 | |
| 239 | static char *last_message; |
| 240 | |
| 241 | NORETURN void |
| 242 | deprecated_throw_reason (enum return_reason reason) |
| 243 | { |
| 244 | struct gdb_exception exception; |
| 245 | memset (&exception, 0, sizeof exception); |
| 246 | |
| 247 | exception.reason = reason; |
| 248 | switch (reason) |
| 249 | { |
| 250 | case RETURN_QUIT: |
| 251 | break; |
| 252 | case RETURN_ERROR: |
| 253 | exception.error = GENERIC_ERROR; |
| 254 | break; |
| 255 | default: |
| 256 | internal_error (__FILE__, __LINE__, _("bad switch")); |
| 257 | } |
| 258 | |
| 259 | throw_exception (exception); |
| 260 | } |
| 261 | |
| 262 | static void |
| 263 | print_flush (void) |
| 264 | { |
| 265 | struct serial *gdb_stdout_serial; |
| 266 | |
| 267 | if (deprecated_error_begin_hook) |
| 268 | deprecated_error_begin_hook (); |
| 269 | target_terminal_ours (); |
| 270 | |
| 271 | /* We want all output to appear now, before we print the error. We |
| 272 | have 3 levels of buffering we have to flush (it's possible that |
| 273 | some of these should be changed to flush the lower-level ones |
| 274 | too): */ |
| 275 | |
| 276 | /* 1. The _filtered buffer. */ |
| 277 | wrap_here (""); |
| 278 | |
| 279 | /* 2. The stdio buffer. */ |
| 280 | gdb_flush (gdb_stdout); |
| 281 | gdb_flush (gdb_stderr); |
| 282 | |
| 283 | /* 3. The system-level buffer. */ |
| 284 | gdb_stdout_serial = serial_fdopen (1); |
| 285 | if (gdb_stdout_serial) |
| 286 | { |
| 287 | serial_drain_output (gdb_stdout_serial); |
| 288 | serial_un_fdopen (gdb_stdout_serial); |
| 289 | } |
| 290 | |
| 291 | annotate_error_begin (); |
| 292 | } |
| 293 | |
| 294 | static void |
| 295 | print_exception (struct ui_file *file, struct gdb_exception e) |
| 296 | { |
| 297 | /* KLUGE: cagney/2005-01-13: Write the string out one line at a time |
| 298 | as that way the MI's behavior is preserved. */ |
| 299 | const char *start; |
| 300 | const char *end; |
| 301 | for (start = e.message; start != NULL; start = end) |
| 302 | { |
| 303 | end = strchr (start, '\n'); |
| 304 | if (end == NULL) |
| 305 | fputs_filtered (start, file); |
| 306 | else |
| 307 | { |
| 308 | end++; |
| 309 | ui_file_write (file, start, end - start); |
| 310 | } |
| 311 | } |
| 312 | fprintf_filtered (file, "\n"); |
| 313 | |
| 314 | /* Now append the annotation. */ |
| 315 | switch (e.reason) |
| 316 | { |
| 317 | case RETURN_QUIT: |
| 318 | annotate_quit (); |
| 319 | break; |
| 320 | case RETURN_ERROR: |
| 321 | /* Assume that these are all errors. */ |
| 322 | annotate_error (); |
| 323 | break; |
| 324 | default: |
| 325 | internal_error (__FILE__, __LINE__, _("Bad switch.")); |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | void |
| 330 | exception_print (struct ui_file *file, struct gdb_exception e) |
| 331 | { |
| 332 | if (e.reason < 0 && e.message != NULL) |
| 333 | { |
| 334 | print_flush (); |
| 335 | print_exception (file, e); |
| 336 | } |
| 337 | } |
| 338 | |
| 339 | void |
| 340 | exception_fprintf (struct ui_file *file, struct gdb_exception e, |
| 341 | const char *prefix, ...) |
| 342 | { |
| 343 | if (e.reason < 0 && e.message != NULL) |
| 344 | { |
| 345 | va_list args; |
| 346 | |
| 347 | print_flush (); |
| 348 | |
| 349 | /* Print the prefix. */ |
| 350 | va_start (args, prefix); |
| 351 | vfprintf_filtered (file, prefix, args); |
| 352 | va_end (args); |
| 353 | |
| 354 | print_exception (file, e); |
| 355 | } |
| 356 | } |
| 357 | |
| 358 | void |
| 359 | print_any_exception (struct ui_file *file, const char *prefix, |
| 360 | struct gdb_exception e) |
| 361 | { |
| 362 | if (e.reason < 0 && e.message != NULL) |
| 363 | { |
| 364 | target_terminal_ours (); |
| 365 | wrap_here (""); /* Force out any buffered output */ |
| 366 | gdb_flush (gdb_stdout); |
| 367 | annotate_error_begin (); |
| 368 | |
| 369 | /* Print the prefix. */ |
| 370 | if (prefix != NULL && prefix[0] != '\0') |
| 371 | fputs_filtered (prefix, file); |
| 372 | print_exception (file, e); |
| 373 | } |
| 374 | } |
| 375 | |
| 376 | NORETURN static void |
| 377 | throw_it (enum return_reason reason, enum errors error, const char *fmt, |
| 378 | va_list ap) ATTR_NORETURN; |
| 379 | NORETURN static void |
| 380 | throw_it (enum return_reason reason, enum errors error, const char *fmt, |
| 381 | va_list ap) |
| 382 | { |
| 383 | struct gdb_exception e; |
| 384 | char *new_message; |
| 385 | |
| 386 | /* Save the message. Create the new message before deleting the |
| 387 | old, the new message may include the old message text. */ |
| 388 | new_message = xstrvprintf (fmt, ap); |
| 389 | xfree (last_message); |
| 390 | last_message = new_message; |
| 391 | |
| 392 | /* Create the exception. */ |
| 393 | e.reason = reason; |
| 394 | e.error = error; |
| 395 | e.message = last_message; |
| 396 | |
| 397 | /* Throw the exception. */ |
| 398 | throw_exception (e); |
| 399 | } |
| 400 | |
| 401 | NORETURN void |
| 402 | throw_verror (enum errors error, const char *fmt, va_list ap) |
| 403 | { |
| 404 | throw_it (RETURN_ERROR, error, fmt, ap); |
| 405 | } |
| 406 | |
| 407 | NORETURN void |
| 408 | throw_vfatal (const char *fmt, va_list ap) |
| 409 | { |
| 410 | throw_it (RETURN_QUIT, NO_ERROR, fmt, ap); |
| 411 | } |
| 412 | |
| 413 | NORETURN void |
| 414 | throw_error (enum errors error, const char *fmt, ...) |
| 415 | { |
| 416 | va_list args; |
| 417 | va_start (args, fmt); |
| 418 | throw_it (RETURN_ERROR, error, fmt, args); |
| 419 | va_end (args); |
| 420 | } |
| 421 | |
| 422 | /* Call FUNC() with args FUNC_UIOUT and FUNC_ARGS, catching any |
| 423 | errors. Set FUNC_CAUGHT to an ``enum return_reason'' if the |
| 424 | function is aborted (using throw_exception() or zero if the |
| 425 | function returns normally. Set FUNC_VAL to the value returned by |
| 426 | the function or 0 if the function was aborted. |
| 427 | |
| 428 | Must not be called with immediate_quit in effect (bad things might |
| 429 | happen, say we got a signal in the middle of a memcpy to quit_return). |
| 430 | This is an OK restriction; with very few exceptions immediate_quit can |
| 431 | be replaced by judicious use of QUIT. |
| 432 | |
| 433 | MASK specifies what to catch; it is normally set to |
| 434 | RETURN_MASK_ALL, if for no other reason than that the code which |
| 435 | calls catch_errors might not be set up to deal with a quit which |
| 436 | isn't caught. But if the code can deal with it, it generally |
| 437 | should be RETURN_MASK_ERROR, unless for some reason it is more |
| 438 | useful to abort only the portion of the operation inside the |
| 439 | catch_errors. Note that quit should return to the command line |
| 440 | fairly quickly, even if some further processing is being done. */ |
| 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 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 | initialize the longjmp buffers. */ |
| 449 | |
| 450 | /* MAYBE: cagney/1999-11-05: Should the catch_errors and cleanups code |
| 451 | be consolidated into a single file instead of being distributed |
| 452 | between utils.c and top.c? */ |
| 453 | |
| 454 | int |
| 455 | catch_exceptions (struct ui_out *uiout, |
| 456 | catch_exceptions_ftype *func, |
| 457 | void *func_args, |
| 458 | return_mask mask) |
| 459 | { |
| 460 | return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask); |
| 461 | } |
| 462 | |
| 463 | struct gdb_exception |
| 464 | catch_exception (struct ui_out *uiout, |
| 465 | catch_exception_ftype *func, |
| 466 | void *func_args, |
| 467 | return_mask mask) |
| 468 | { |
| 469 | volatile struct gdb_exception exception; |
| 470 | TRY_CATCH (exception, mask) |
| 471 | { |
| 472 | (*func) (uiout, func_args); |
| 473 | } |
| 474 | return exception; |
| 475 | } |
| 476 | |
| 477 | int |
| 478 | catch_exceptions_with_msg (struct ui_out *uiout, |
| 479 | catch_exceptions_ftype *func, |
| 480 | void *func_args, |
| 481 | char **gdberrmsg, |
| 482 | return_mask mask) |
| 483 | { |
| 484 | volatile struct gdb_exception exception; |
| 485 | volatile int val = 0; |
| 486 | TRY_CATCH (exception, mask) |
| 487 | { |
| 488 | val = (*func) (uiout, func_args); |
| 489 | } |
| 490 | print_any_exception (gdb_stderr, NULL, exception); |
| 491 | gdb_assert (val >= 0); |
| 492 | gdb_assert (exception.reason <= 0); |
| 493 | if (exception.reason < 0) |
| 494 | { |
| 495 | /* If caller wants a copy of the low-level error message, make |
| 496 | one. This is used in the case of a silent error whereby the |
| 497 | caller may optionally want to issue the message. */ |
| 498 | if (gdberrmsg != NULL) |
| 499 | { |
| 500 | if (exception.message != NULL) |
| 501 | *gdberrmsg = xstrdup (exception.message); |
| 502 | else |
| 503 | *gdberrmsg = NULL; |
| 504 | } |
| 505 | return exception.reason; |
| 506 | } |
| 507 | return val; |
| 508 | } |
| 509 | |
| 510 | int |
| 511 | catch_errors (catch_errors_ftype *func, void *func_args, char *errstring, |
| 512 | return_mask mask) |
| 513 | { |
| 514 | volatile int val = 0; |
| 515 | volatile struct gdb_exception exception; |
| 516 | TRY_CATCH (exception, mask) |
| 517 | { |
| 518 | val = func (func_args); |
| 519 | } |
| 520 | print_any_exception (gdb_stderr, errstring, exception); |
| 521 | if (exception.reason != 0) |
| 522 | return 0; |
| 523 | return val; |
| 524 | } |
| 525 | |
| 526 | int |
| 527 | catch_command_errors (catch_command_errors_ftype * command, |
| 528 | char *arg, int from_tty, return_mask mask) |
| 529 | { |
| 530 | volatile struct gdb_exception e; |
| 531 | TRY_CATCH (e, mask) |
| 532 | { |
| 533 | command (arg, from_tty); |
| 534 | } |
| 535 | print_any_exception (gdb_stderr, NULL, e); |
| 536 | if (e.reason < 0) |
| 537 | return 0; |
| 538 | return 1; |
| 539 | } |