Commit | Line | Data |
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60250e8b AC |
1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
2 | ||
3 | Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, | |
05ff989b AC |
4 | 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free |
5 | Software Foundation, Inc. | |
60250e8b AC |
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 <setjmp.h> | |
27 | #include "breakpoint.h" | |
28 | #include "target.h" | |
29 | #include "inferior.h" | |
30 | #include "annotate.h" | |
31 | #include "ui-out.h" | |
32 | #include "gdb_assert.h" | |
db5f402d | 33 | #include "gdb_string.h" |
e06e2353 | 34 | #include "serial.h" |
60250e8b | 35 | |
c1043fc2 AC |
36 | const struct exception exception_none = { 0, NO_ERROR, NULL }; |
37 | ||
60250e8b AC |
38 | /* One should use catch_errors rather than manipulating these |
39 | directly. */ | |
40 | #if defined(HAVE_SIGSETJMP) | |
41 | #define SIGJMP_BUF sigjmp_buf | |
42 | #define SIGSETJMP(buf) sigsetjmp((buf), 1) | |
43 | #define SIGLONGJMP(buf,val) siglongjmp((buf), (val)) | |
44 | #else | |
45 | #define SIGJMP_BUF jmp_buf | |
46 | #define SIGSETJMP(buf) setjmp(buf) | |
47 | #define SIGLONGJMP(buf,val) longjmp((buf), (val)) | |
48 | #endif | |
49 | ||
db5f402d AC |
50 | /* Possible catcher states. */ |
51 | enum catcher_state { | |
52 | /* Initial state, a new catcher has just been created. */ | |
53 | CATCHER_CREATED, | |
54 | /* The catch code is running. */ | |
55 | CATCHER_RUNNING, | |
56 | CATCHER_RUNNING_1, | |
57 | /* The catch code threw an exception. */ | |
58 | CATCHER_ABORTING | |
59 | }; | |
60 | ||
61 | /* Possible catcher actions. */ | |
62 | enum catcher_action { | |
63 | CATCH_ITER, | |
64 | CATCH_ITER_1, | |
65 | CATCH_THROWING | |
66 | }; | |
67 | ||
68 | struct catcher | |
69 | { | |
70 | enum catcher_state state; | |
2a78bfb5 | 71 | /* Jump buffer pointing back at the exception handler. */ |
db5f402d | 72 | SIGJMP_BUF buf; |
8a076db9 | 73 | /* Status buffer belonging to the exception handler. */ |
2a78bfb5 | 74 | volatile struct exception *exception; |
db5f402d AC |
75 | /* Saved/current state. */ |
76 | int mask; | |
db5f402d AC |
77 | struct ui_out *saved_uiout; |
78 | struct cleanup *saved_cleanup_chain; | |
db5f402d AC |
79 | /* Back link. */ |
80 | struct catcher *prev; | |
81 | }; | |
82 | ||
60250e8b | 83 | /* Where to go for throw_exception(). */ |
db5f402d AC |
84 | static struct catcher *current_catcher; |
85 | ||
86 | static SIGJMP_BUF * | |
87 | catcher_init (struct ui_out *func_uiout, | |
2a78bfb5 | 88 | volatile struct exception *exception, |
3af1e0e3 | 89 | return_mask mask) |
db5f402d AC |
90 | { |
91 | struct catcher *new_catcher = XZALLOC (struct catcher); | |
92 | ||
2a78bfb5 AC |
93 | /* Start with no exception, save it's address. */ |
94 | exception->reason = 0; | |
95 | exception->error = NO_ERROR; | |
96 | exception->message = NULL; | |
97 | new_catcher->exception = exception; | |
98 | ||
db5f402d AC |
99 | new_catcher->mask = mask; |
100 | ||
db5f402d AC |
101 | /* Override the global ``struct ui_out'' builder. */ |
102 | new_catcher->saved_uiout = uiout; | |
103 | uiout = func_uiout; | |
104 | ||
105 | /* Prevent error/quit during FUNC from calling cleanups established | |
106 | prior to here. */ | |
107 | new_catcher->saved_cleanup_chain = save_cleanups (); | |
108 | ||
109 | /* Push this new catcher on the top. */ | |
110 | new_catcher->prev = current_catcher; | |
111 | current_catcher = new_catcher; | |
112 | new_catcher->state = CATCHER_CREATED; | |
113 | ||
114 | return &new_catcher->buf; | |
115 | } | |
116 | ||
117 | static void | |
118 | catcher_pop (void) | |
119 | { | |
120 | struct catcher *old_catcher = current_catcher; | |
121 | current_catcher = old_catcher->prev; | |
122 | ||
123 | /* Restore the cleanup chain, the error/quit messages, and the uiout | |
124 | builder, to their original states. */ | |
125 | ||
126 | restore_cleanups (old_catcher->saved_cleanup_chain); | |
127 | ||
128 | uiout = old_catcher->saved_uiout; | |
129 | ||
db5f402d AC |
130 | xfree (old_catcher); |
131 | } | |
132 | ||
133 | /* Catcher state machine. Returns non-zero if the m/c should be run | |
134 | again, zero if it should abort. */ | |
135 | ||
136 | int | |
137 | catcher_state_machine (enum catcher_action action) | |
138 | { | |
139 | switch (current_catcher->state) | |
140 | { | |
141 | case CATCHER_CREATED: | |
142 | switch (action) | |
143 | { | |
144 | case CATCH_ITER: | |
145 | /* Allow the code to run the catcher. */ | |
146 | current_catcher->state = CATCHER_RUNNING; | |
147 | return 1; | |
148 | default: | |
149 | internal_error (__FILE__, __LINE__, "bad state"); | |
150 | } | |
151 | case CATCHER_RUNNING: | |
152 | switch (action) | |
153 | { | |
154 | case CATCH_ITER: | |
155 | /* No error/quit has occured. Just clean up. */ | |
156 | catcher_pop (); | |
157 | return 0; | |
158 | case CATCH_ITER_1: | |
159 | current_catcher->state = CATCHER_RUNNING_1; | |
160 | return 1; | |
161 | case CATCH_THROWING: | |
162 | current_catcher->state = CATCHER_ABORTING; | |
163 | /* See also throw_exception. */ | |
164 | return 1; | |
165 | default: | |
166 | internal_error (__FILE__, __LINE__, "bad switch"); | |
167 | } | |
168 | case CATCHER_RUNNING_1: | |
169 | switch (action) | |
170 | { | |
171 | case CATCH_ITER: | |
172 | /* The did a "break" from the inner while loop. */ | |
173 | catcher_pop (); | |
174 | return 0; | |
175 | case CATCH_ITER_1: | |
176 | current_catcher->state = CATCHER_RUNNING; | |
177 | return 0; | |
178 | case CATCH_THROWING: | |
179 | current_catcher->state = CATCHER_ABORTING; | |
180 | /* See also throw_exception. */ | |
181 | return 1; | |
182 | default: | |
183 | internal_error (__FILE__, __LINE__, "bad switch"); | |
184 | } | |
185 | case CATCHER_ABORTING: | |
186 | switch (action) | |
187 | { | |
188 | case CATCH_ITER: | |
189 | { | |
2a78bfb5 AC |
190 | struct exception exception = *current_catcher->exception; |
191 | if (current_catcher->mask & RETURN_MASK (exception.reason)) | |
db5f402d AC |
192 | { |
193 | /* Exit normally if this catcher can handle this | |
194 | exception. The caller analyses the func return | |
195 | values. */ | |
196 | catcher_pop (); | |
197 | return 0; | |
198 | } | |
199 | /* The caller didn't request that the event be caught, | |
200 | relay the event to the next containing | |
201 | catch_errors(). */ | |
202 | catcher_pop (); | |
2a78bfb5 | 203 | throw_exception (exception); |
db5f402d AC |
204 | } |
205 | default: | |
206 | internal_error (__FILE__, __LINE__, "bad state"); | |
207 | } | |
208 | default: | |
209 | internal_error (__FILE__, __LINE__, "bad switch"); | |
210 | } | |
211 | } | |
60250e8b | 212 | |
2a78bfb5 | 213 | /* Return EXCEPTION to the nearest containing catch_errors(). */ |
60250e8b AC |
214 | |
215 | NORETURN void | |
2a78bfb5 | 216 | throw_exception (struct exception exception) |
60250e8b AC |
217 | { |
218 | quit_flag = 0; | |
219 | immediate_quit = 0; | |
220 | ||
221 | /* Perhaps it would be cleaner to do this via the cleanup chain (not sure | |
222 | I can think of a reason why that is vital, though). */ | |
223 | bpstat_clear_actions (stop_bpstat); /* Clear queued breakpoint commands */ | |
224 | ||
225 | disable_current_display (); | |
226 | do_cleanups (ALL_CLEANUPS); | |
227 | if (target_can_async_p () && !target_executing) | |
228 | do_exec_cleanups (ALL_CLEANUPS); | |
229 | if (sync_execution) | |
230 | do_exec_error_cleanups (ALL_CLEANUPS); | |
231 | ||
60250e8b AC |
232 | /* Jump to the containing catch_errors() call, communicating REASON |
233 | to that call via setjmp's return value. Note that REASON can't | |
234 | be zero, by definition in defs.h. */ | |
db5f402d | 235 | catcher_state_machine (CATCH_THROWING); |
2a78bfb5 AC |
236 | *current_catcher->exception = exception; |
237 | SIGLONGJMP (current_catcher->buf, exception.reason); | |
238 | } | |
239 | ||
6b1b7650 AC |
240 | static char *last_message; |
241 | ||
2a78bfb5 | 242 | NORETURN void |
315a522e | 243 | deprecated_throw_reason (enum return_reason reason) |
2a78bfb5 AC |
244 | { |
245 | struct exception exception; | |
246 | memset (&exception, 0, sizeof exception); | |
247 | ||
248 | exception.reason = reason; | |
249 | switch (reason) | |
250 | { | |
251 | case RETURN_QUIT: | |
252 | break; | |
253 | case RETURN_ERROR: | |
254 | exception.error = GENERIC_ERROR; | |
2a78bfb5 AC |
255 | break; |
256 | default: | |
257 | internal_error (__FILE__, __LINE__, "bad switch"); | |
258 | } | |
259 | ||
260 | throw_exception (exception); | |
60250e8b AC |
261 | } |
262 | ||
6b1b7650 | 263 | static void |
c6da7a6d | 264 | print_flush (void) |
6b1b7650 | 265 | { |
e06e2353 AC |
266 | struct serial *gdb_stdout_serial; |
267 | ||
c6da7a6d AC |
268 | if (deprecated_error_begin_hook) |
269 | deprecated_error_begin_hook (); | |
270 | target_terminal_ours (); | |
e06e2353 AC |
271 | |
272 | /* We want all output to appear now, before we print the error. We | |
273 | have 3 levels of buffering we have to flush (it's possible that | |
274 | some of these should be changed to flush the lower-level ones | |
275 | too): */ | |
276 | ||
277 | /* 1. The _filtered buffer. */ | |
278 | wrap_here (""); | |
279 | ||
280 | /* 2. The stdio buffer. */ | |
c6da7a6d | 281 | gdb_flush (gdb_stdout); |
e06e2353 AC |
282 | gdb_flush (gdb_stderr); |
283 | ||
284 | /* 3. The system-level buffer. */ | |
285 | gdb_stdout_serial = serial_fdopen (1); | |
286 | serial_drain_output (gdb_stdout_serial); | |
287 | serial_un_fdopen (gdb_stdout_serial); | |
288 | ||
c6da7a6d | 289 | annotate_error_begin (); |
6b1b7650 AC |
290 | } |
291 | ||
9cbc821d AC |
292 | static void |
293 | print_exception (struct ui_file *file, struct exception e) | |
294 | { | |
295 | /* KLUGE: cagney/2005-01-13: Write the string out one line at a time | |
296 | as that way the MI's behavior is preserved. */ | |
297 | const char *start; | |
298 | const char *end; | |
299 | for (start = e.message; start != NULL; start = end) | |
300 | { | |
301 | end = strchr (start, '\n'); | |
302 | if (end == NULL) | |
303 | fputs_filtered (start, file); | |
304 | else | |
305 | { | |
306 | end++; | |
307 | ui_file_write (file, start, end - start); | |
308 | } | |
309 | } | |
c6da7a6d | 310 | fprintf_filtered (file, "\n"); |
e48f5bee AC |
311 | |
312 | /* Now append the annotation. */ | |
313 | switch (e.reason) | |
314 | { | |
315 | case RETURN_QUIT: | |
316 | annotate_quit (); | |
317 | break; | |
318 | case RETURN_ERROR: | |
319 | /* Assume that these are all errors. */ | |
320 | annotate_error (); | |
321 | break; | |
322 | default: | |
323 | internal_error (__FILE__, __LINE__, _("Bad switch.")); | |
324 | } | |
9cbc821d AC |
325 | } |
326 | ||
8a076db9 | 327 | void |
9cbc821d | 328 | exception_print (struct ui_file *file, struct exception e) |
8a076db9 AC |
329 | { |
330 | if (e.reason < 0 && e.message != NULL) | |
331 | { | |
c6da7a6d | 332 | print_flush (); |
9cbc821d | 333 | print_exception (file, e); |
9cbc821d AC |
334 | } |
335 | } | |
8a076db9 | 336 | |
9cbc821d AC |
337 | void |
338 | exception_fprintf (struct ui_file *file, struct exception e, | |
339 | const char *prefix, ...) | |
340 | { | |
341 | if (e.reason < 0 && e.message != NULL) | |
342 | { | |
343 | va_list args; | |
c6da7a6d AC |
344 | |
345 | print_flush (); | |
9cbc821d AC |
346 | |
347 | /* Print the prefix. */ | |
348 | va_start (args, prefix); | |
349 | vfprintf_filtered (file, prefix, args); | |
350 | va_end (args); | |
351 | ||
352 | print_exception (file, e); | |
8a076db9 AC |
353 | } |
354 | } | |
355 | ||
e48f5bee AC |
356 | void |
357 | print_any_exception (struct ui_file *file, const char *prefix, | |
358 | struct exception e) | |
359 | { | |
360 | if (e.reason < 0 && e.message != NULL) | |
361 | { | |
362 | target_terminal_ours (); | |
363 | wrap_here (""); /* Force out any buffered output */ | |
364 | gdb_flush (gdb_stdout); | |
365 | annotate_error_begin (); | |
366 | ||
367 | /* Print the prefix. */ | |
368 | if (prefix != NULL && prefix[0] != '\0') | |
369 | fputs_filtered (prefix, file); | |
370 | print_exception (file, e); | |
371 | } | |
372 | } | |
373 | ||
6b1b7650 | 374 | NORETURN static void |
3af1e0e3 AC |
375 | throw_it (enum return_reason reason, enum errors error, const char *fmt, |
376 | va_list ap) ATTR_NORETURN; | |
6b1b7650 | 377 | NORETURN static void |
3af1e0e3 AC |
378 | throw_it (enum return_reason reason, enum errors error, const char *fmt, |
379 | va_list ap) | |
6b1b7650 | 380 | { |
6b1b7650 | 381 | struct exception e; |
17d92a02 | 382 | char *new_message; |
6b1b7650 | 383 | |
17d92a02 AC |
384 | /* Save the message. Create the new message before deleting the |
385 | old, the new message may include the old message text. */ | |
386 | new_message = xstrvprintf (fmt, ap); | |
6b1b7650 | 387 | xfree (last_message); |
17d92a02 | 388 | last_message = new_message; |
c6da7a6d AC |
389 | |
390 | /* Create the exception. */ | |
391 | e.reason = reason; | |
392 | e.error = error; | |
393 | e.message = last_message; | |
6b1b7650 | 394 | |
6b1b7650 | 395 | /* Throw the exception. */ |
6b1b7650 AC |
396 | throw_exception (e); |
397 | } | |
398 | ||
399 | NORETURN void | |
400 | throw_verror (enum errors error, const char *fmt, va_list ap) | |
401 | { | |
3af1e0e3 | 402 | throw_it (RETURN_ERROR, error, fmt, ap); |
6b1b7650 AC |
403 | } |
404 | ||
405 | NORETURN void | |
406 | throw_vfatal (const char *fmt, va_list ap) | |
407 | { | |
3af1e0e3 | 408 | throw_it (RETURN_QUIT, NO_ERROR, fmt, ap); |
6b1b7650 AC |
409 | } |
410 | ||
411 | NORETURN void | |
05ff989b | 412 | throw_error (enum errors error, const char *fmt, ...) |
6b1b7650 | 413 | { |
05ff989b AC |
414 | va_list args; |
415 | va_start (args, fmt); | |
3af1e0e3 | 416 | throw_it (RETURN_ERROR, error, fmt, args); |
05ff989b | 417 | va_end (args); |
6b1b7650 AC |
418 | } |
419 | ||
60250e8b AC |
420 | /* Call FUNC() with args FUNC_UIOUT and FUNC_ARGS, catching any |
421 | errors. Set FUNC_CAUGHT to an ``enum return_reason'' if the | |
422 | function is aborted (using throw_exception() or zero if the | |
423 | function returns normally. Set FUNC_VAL to the value returned by | |
424 | the function or 0 if the function was aborted. | |
425 | ||
426 | Must not be called with immediate_quit in effect (bad things might | |
427 | happen, say we got a signal in the middle of a memcpy to quit_return). | |
428 | This is an OK restriction; with very few exceptions immediate_quit can | |
429 | be replaced by judicious use of QUIT. | |
430 | ||
431 | MASK specifies what to catch; it is normally set to | |
432 | RETURN_MASK_ALL, if for no other reason than that the code which | |
433 | calls catch_errors might not be set up to deal with a quit which | |
434 | isn't caught. But if the code can deal with it, it generally | |
435 | should be RETURN_MASK_ERROR, unless for some reason it is more | |
436 | useful to abort only the portion of the operation inside the | |
437 | catch_errors. Note that quit should return to the command line | |
438 | fairly quickly, even if some further processing is being done. */ | |
439 | ||
440 | /* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with | |
441 | error() et.al. could maintain a set of flags that indicate the the | |
442 | current state of each of the longjmp buffers. This would give the | |
443 | longjmp code the chance to detect a longjmp botch (before it gets | |
444 | to longjmperror()). Prior to 1999-11-05 this wasn't possible as | |
445 | code also randomly used a SET_TOP_LEVEL macro that directly | |
446 | initialize the longjmp buffers. */ | |
447 | ||
448 | /* MAYBE: cagney/1999-11-05: Should the catch_errors and cleanups code | |
449 | be consolidated into a single file instead of being distributed | |
450 | between utils.c and top.c? */ | |
451 | ||
60250e8b AC |
452 | int |
453 | catch_exceptions (struct ui_out *uiout, | |
454 | catch_exceptions_ftype *func, | |
455 | void *func_args, | |
60250e8b AC |
456 | return_mask mask) |
457 | { | |
1c3c7ee7 | 458 | return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask); |
60250e8b AC |
459 | } |
460 | ||
2a78bfb5 AC |
461 | struct exception |
462 | catch_exception (struct ui_out *uiout, | |
463 | catch_exception_ftype *func, | |
464 | void *func_args, | |
465 | return_mask mask) | |
466 | { | |
467 | volatile struct exception exception; | |
468 | SIGJMP_BUF *catch; | |
6212a5e9 | 469 | catch = catcher_init (uiout, &exception, mask); |
2a78bfb5 AC |
470 | for (SIGSETJMP ((*catch)); |
471 | catcher_state_machine (CATCH_ITER);) | |
472 | (*func) (uiout, func_args); | |
473 | return exception; | |
474 | } | |
475 | ||
60250e8b AC |
476 | int |
477 | catch_exceptions_with_msg (struct ui_out *uiout, | |
478 | catch_exceptions_ftype *func, | |
479 | void *func_args, | |
60250e8b AC |
480 | char **gdberrmsg, |
481 | return_mask mask) | |
482 | { | |
2a78bfb5 AC |
483 | volatile struct exception exception; |
484 | volatile int val = 0; | |
6212a5e9 | 485 | SIGJMP_BUF *catch = catcher_init (uiout, &exception, mask); |
2a78bfb5 | 486 | for (SIGSETJMP ((*catch)); catcher_state_machine (CATCH_ITER);) |
db5f402d | 487 | val = (*func) (uiout, func_args); |
e48f5bee | 488 | print_any_exception (gdb_stderr, NULL, exception); |
60250e8b | 489 | gdb_assert (val >= 0); |
2a78bfb5 AC |
490 | gdb_assert (exception.reason <= 0); |
491 | if (exception.reason < 0) | |
492 | { | |
493 | /* If caller wants a copy of the low-level error message, make | |
494 | one. This is used in the case of a silent error whereby the | |
495 | caller may optionally want to issue the message. */ | |
496 | if (gdberrmsg != NULL) | |
6b1b7650 AC |
497 | { |
498 | if (exception.message != NULL) | |
499 | *gdberrmsg = xstrdup (exception.message); | |
500 | else | |
501 | *gdberrmsg = NULL; | |
502 | } | |
2a78bfb5 AC |
503 | return exception.reason; |
504 | } | |
60250e8b AC |
505 | return val; |
506 | } | |
507 | ||
60250e8b AC |
508 | int |
509 | catch_errors (catch_errors_ftype *func, void *func_args, char *errstring, | |
510 | return_mask mask) | |
511 | { | |
2a78bfb5 AC |
512 | volatile int val = 0; |
513 | volatile struct exception exception; | |
6212a5e9 | 514 | SIGJMP_BUF *catch = catcher_init (uiout, &exception, mask); |
db5f402d AC |
515 | /* This illustrates how it is possible to nest the mechanism and |
516 | hence catch "break". Of course this doesn't address the need to | |
517 | also catch "return". */ | |
2a78bfb5 AC |
518 | for (SIGSETJMP ((*catch)); catcher_state_machine (CATCH_ITER);) |
519 | val = func (func_args); | |
e48f5bee | 520 | print_any_exception (gdb_stderr, errstring, exception); |
2a78bfb5 | 521 | if (exception.reason != 0) |
60250e8b AC |
522 | return 0; |
523 | return val; | |
524 | } | |
525 | ||
60250e8b AC |
526 | int |
527 | catch_command_errors (catch_command_errors_ftype * command, | |
528 | char *arg, int from_tty, return_mask mask) | |
529 | { | |
5a14cc1a | 530 | volatile struct exception e; |
6212a5e9 | 531 | SIGJMP_BUF *catch = catcher_init (uiout, &e, mask); |
5a14cc1a AC |
532 | for (SIGSETJMP ((*catch)); catcher_state_machine (CATCH_ITER);) |
533 | command (arg, from_tty); | |
534 | print_any_exception (gdb_stderr, NULL, e); | |
535 | if (e.reason < 0) | |
536 | return 0; | |
537 | return 1; | |
60250e8b | 538 | } |