1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger.
3 Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
4 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
5 2009, 2010, 2011 Free Software Foundation, Inc.
7 This file is part of GDB.
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 3 of the License, or
12 (at your option) any later version.
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.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "exceptions.h"
24 #include "breakpoint.h"
29 #include "gdb_assert.h"
30 #include "gdb_string.h"
32 #include "gdbthread.h"
34 const struct gdb_exception exception_none = { 0, GDB_NO_ERROR, NULL };
36 /* Possible catcher states. */
38 /* Initial state, a new catcher has just been created. */
40 /* The catch code is running. */
43 /* The catch code threw an exception. */
47 /* Possible catcher actions. */
56 enum catcher_state state;
57 /* Jump buffer pointing back at the exception handler. */
58 EXCEPTIONS_SIGJMP_BUF buf;
59 /* Status buffer belonging to the exception handler. */
60 volatile struct gdb_exception *exception;
61 /* Saved/current state. */
63 struct cleanup *saved_cleanup_chain;
68 /* Where to go for throw_exception(). */
69 static struct catcher *current_catcher;
71 EXCEPTIONS_SIGJMP_BUF *
72 exceptions_state_mc_init (volatile struct gdb_exception *exception,
75 struct catcher *new_catcher = XZALLOC (struct catcher);
77 /* Start with no exception, save it's address. */
78 exception->reason = 0;
79 exception->error = GDB_NO_ERROR;
80 exception->message = NULL;
81 new_catcher->exception = exception;
83 new_catcher->mask = mask;
85 /* Prevent error/quit during FUNC from calling cleanups established
87 new_catcher->saved_cleanup_chain = save_cleanups ();
89 /* Push this new catcher on the top. */
90 new_catcher->prev = current_catcher;
91 current_catcher = new_catcher;
92 new_catcher->state = CATCHER_CREATED;
94 return &new_catcher->buf;
100 struct catcher *old_catcher = current_catcher;
102 current_catcher = old_catcher->prev;
104 /* Restore the cleanup chain, the error/quit messages, and the uiout
105 builder, to their original states. */
107 restore_cleanups (old_catcher->saved_cleanup_chain);
112 /* Catcher state machine. Returns non-zero if the m/c should be run
113 again, zero if it should abort. */
116 exceptions_state_mc (enum catcher_action action)
118 switch (current_catcher->state)
120 case CATCHER_CREATED:
124 /* Allow the code to run the catcher. */
125 current_catcher->state = CATCHER_RUNNING;
128 internal_error (__FILE__, __LINE__, _("bad state"));
130 case CATCHER_RUNNING:
134 /* No error/quit has occured. Just clean up. */
138 current_catcher->state = CATCHER_RUNNING_1;
141 current_catcher->state = CATCHER_ABORTING;
142 /* See also throw_exception. */
145 internal_error (__FILE__, __LINE__, _("bad switch"));
147 case CATCHER_RUNNING_1:
151 /* The did a "break" from the inner while loop. */
155 current_catcher->state = CATCHER_RUNNING;
158 current_catcher->state = CATCHER_ABORTING;
159 /* See also throw_exception. */
162 internal_error (__FILE__, __LINE__, _("bad switch"));
164 case CATCHER_ABORTING:
169 struct gdb_exception exception = *current_catcher->exception;
171 if (current_catcher->mask & RETURN_MASK (exception.reason))
173 /* Exit normally if this catcher can handle this
174 exception. The caller analyses the func return
179 /* The caller didn't request that the event be caught,
180 relay the event to the next containing
183 throw_exception (exception);
186 internal_error (__FILE__, __LINE__, _("bad state"));
189 internal_error (__FILE__, __LINE__, _("bad switch"));
194 exceptions_state_mc_action_iter (void)
196 return exceptions_state_mc (CATCH_ITER);
200 exceptions_state_mc_action_iter_1 (void)
202 return exceptions_state_mc (CATCH_ITER_1);
205 /* Return EXCEPTION to the nearest containing catch_errors(). */
208 throw_exception (struct gdb_exception exception)
213 do_cleanups (ALL_CLEANUPS);
215 /* Jump to the containing catch_errors() call, communicating REASON
216 to that call via setjmp's return value. Note that REASON can't
217 be zero, by definition in defs.h. */
218 exceptions_state_mc (CATCH_THROWING);
219 *current_catcher->exception = exception;
220 EXCEPTIONS_SIGLONGJMP (current_catcher->buf, exception.reason);
223 static char *last_message;
226 deprecated_throw_reason (enum return_reason reason)
228 struct gdb_exception exception;
230 memset (&exception, 0, sizeof exception);
232 exception.reason = reason;
238 exception.error = GENERIC_ERROR;
241 internal_error (__FILE__, __LINE__, _("bad switch"));
244 throw_exception (exception);
250 struct serial *gdb_stdout_serial;
252 if (deprecated_error_begin_hook)
253 deprecated_error_begin_hook ();
254 target_terminal_ours ();
256 /* We want all output to appear now, before we print the error. We
257 have 3 levels of buffering we have to flush (it's possible that
258 some of these should be changed to flush the lower-level ones
261 /* 1. The _filtered buffer. */
264 /* 2. The stdio buffer. */
265 gdb_flush (gdb_stdout);
266 gdb_flush (gdb_stderr);
268 /* 3. The system-level buffer. */
269 gdb_stdout_serial = serial_fdopen (1);
270 if (gdb_stdout_serial)
272 serial_drain_output (gdb_stdout_serial);
273 serial_un_fdopen (gdb_stdout_serial);
276 annotate_error_begin ();
280 print_exception (struct ui_file *file, struct gdb_exception e)
282 /* KLUGE: cagney/2005-01-13: Write the string out one line at a time
283 as that way the MI's behavior is preserved. */
287 for (start = e.message; start != NULL; start = end)
289 end = strchr (start, '\n');
291 fputs_filtered (start, file);
295 ui_file_write (file, start, end - start);
298 fprintf_filtered (file, "\n");
300 /* Now append the annotation. */
307 /* Assume that these are all errors. */
311 internal_error (__FILE__, __LINE__, _("Bad switch."));
316 exception_print (struct ui_file *file, struct gdb_exception e)
318 if (e.reason < 0 && e.message != NULL)
321 print_exception (file, e);
326 exception_fprintf (struct ui_file *file, struct gdb_exception e,
327 const char *prefix, ...)
329 if (e.reason < 0 && e.message != NULL)
335 /* Print the prefix. */
336 va_start (args, prefix);
337 vfprintf_filtered (file, prefix, args);
340 print_exception (file, e);
345 print_any_exception (struct ui_file *file, const char *prefix,
346 struct gdb_exception e)
348 if (e.reason < 0 && e.message != NULL)
350 target_terminal_ours ();
351 wrap_here (""); /* Force out any buffered output. */
352 gdb_flush (gdb_stdout);
353 annotate_error_begin ();
355 /* Print the prefix. */
356 if (prefix != NULL && prefix[0] != '\0')
357 fputs_filtered (prefix, file);
358 print_exception (file, e);
362 static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0)
363 throw_it (enum return_reason reason, enum errors error, const char *fmt,
366 struct gdb_exception e;
369 /* Save the message. Create the new message before deleting the
370 old, the new message may include the old message text. */
371 new_message = xstrvprintf (fmt, ap);
372 xfree (last_message);
373 last_message = new_message;
375 /* Create the exception. */
378 e.message = last_message;
380 /* Throw the exception. */
385 throw_verror (enum errors error, const char *fmt, va_list ap)
387 throw_it (RETURN_ERROR, error, fmt, ap);
391 throw_vfatal (const char *fmt, va_list ap)
393 throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap);
397 throw_error (enum errors error, const char *fmt, ...)
401 va_start (args, fmt);
402 throw_it (RETURN_ERROR, error, fmt, args);
406 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
407 handler. If an exception (enum return_reason) is thrown using
408 throw_exception() than all cleanups installed since
409 catch_exceptions() was entered are invoked, the (-ve) exception
410 value is then returned by catch_exceptions. If FUNC() returns
411 normally (with a positive or zero return value) then that value is
412 returned by catch_exceptions(). It is an internal_error() for
413 FUNC() to return a negative value.
415 See exceptions.h for further usage details.
417 Must not be called with immediate_quit in effect (bad things might
418 happen, say we got a signal in the middle of a memcpy to quit_return).
419 This is an OK restriction; with very few exceptions immediate_quit can
420 be replaced by judicious use of QUIT. */
422 /* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with
423 error() et al. could maintain a set of flags that indicate the
424 current state of each of the longjmp buffers. This would give the
425 longjmp code the chance to detect a longjmp botch (before it gets
426 to longjmperror()). Prior to 1999-11-05 this wasn't possible as
427 code also randomly used a SET_TOP_LEVEL macro that directly
428 initialized the longjmp buffers. */
431 catch_exceptions (struct ui_out *uiout,
432 catch_exceptions_ftype *func,
436 return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask);
440 catch_exceptions_with_msg (struct ui_out *func_uiout,
441 catch_exceptions_ftype *func,
446 volatile struct gdb_exception exception;
447 volatile int val = 0;
448 struct ui_out *saved_uiout;
450 /* Save and override the global ``struct ui_out'' builder. */
451 saved_uiout = current_uiout;
452 current_uiout = func_uiout;
454 TRY_CATCH (exception, RETURN_MASK_ALL)
456 val = (*func) (current_uiout, func_args);
459 /* Restore the global builder. */
460 current_uiout = saved_uiout;
462 if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0)
464 /* The caller didn't request that the event be caught.
466 throw_exception (exception);
469 print_any_exception (gdb_stderr, NULL, exception);
470 gdb_assert (val >= 0);
471 gdb_assert (exception.reason <= 0);
472 if (exception.reason < 0)
474 /* If caller wants a copy of the low-level error message, make
475 one. This is used in the case of a silent error whereby the
476 caller may optionally want to issue the message. */
477 if (gdberrmsg != NULL)
479 if (exception.message != NULL)
480 *gdberrmsg = xstrdup (exception.message);
484 return exception.reason;
489 /* This function is superseded by catch_exceptions(). */
492 catch_errors (catch_errors_ftype *func, void *func_args, char *errstring,
495 volatile int val = 0;
496 volatile struct gdb_exception exception;
497 struct ui_out *saved_uiout;
499 /* Save the global ``struct ui_out'' builder. */
500 saved_uiout = current_uiout;
502 TRY_CATCH (exception, RETURN_MASK_ALL)
504 val = func (func_args);
507 /* Restore the global builder. */
508 current_uiout = saved_uiout;
510 if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0)
512 /* The caller didn't request that the event be caught.
514 throw_exception (exception);
517 print_any_exception (gdb_stderr, errstring, exception);
518 if (exception.reason != 0)
524 catch_command_errors (catch_command_errors_ftype * command,
525 char *arg, int from_tty, return_mask mask)
527 volatile struct gdb_exception e;
531 command (arg, from_tty);
533 print_any_exception (gdb_stderr, NULL, e);