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 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 ui_out *saved_uiout;
64 struct cleanup *saved_cleanup_chain;
69 /* Where to go for throw_exception(). */
70 static struct catcher *current_catcher;
72 EXCEPTIONS_SIGJMP_BUF *
73 exceptions_state_mc_init (struct ui_out *func_uiout,
74 volatile struct gdb_exception *exception,
77 struct catcher *new_catcher = XZALLOC (struct catcher);
79 /* Start with no exception, save it's address. */
80 exception->reason = 0;
81 exception->error = GDB_NO_ERROR;
82 exception->message = NULL;
83 new_catcher->exception = exception;
85 new_catcher->mask = mask;
87 /* Override the global ``struct ui_out'' builder. */
88 new_catcher->saved_uiout = uiout;
91 /* Prevent error/quit during FUNC from calling cleanups established
93 new_catcher->saved_cleanup_chain = save_cleanups ();
95 /* Push this new catcher on the top. */
96 new_catcher->prev = current_catcher;
97 current_catcher = new_catcher;
98 new_catcher->state = CATCHER_CREATED;
100 return &new_catcher->buf;
106 struct catcher *old_catcher = current_catcher;
108 current_catcher = old_catcher->prev;
110 /* Restore the cleanup chain, the error/quit messages, and the uiout
111 builder, to their original states. */
113 restore_cleanups (old_catcher->saved_cleanup_chain);
115 uiout = old_catcher->saved_uiout;
120 /* Catcher state machine. Returns non-zero if the m/c should be run
121 again, zero if it should abort. */
124 exceptions_state_mc (enum catcher_action action)
126 switch (current_catcher->state)
128 case CATCHER_CREATED:
132 /* Allow the code to run the catcher. */
133 current_catcher->state = CATCHER_RUNNING;
136 internal_error (__FILE__, __LINE__, _("bad state"));
138 case CATCHER_RUNNING:
142 /* No error/quit has occured. Just clean up. */
146 current_catcher->state = CATCHER_RUNNING_1;
149 current_catcher->state = CATCHER_ABORTING;
150 /* See also throw_exception. */
153 internal_error (__FILE__, __LINE__, _("bad switch"));
155 case CATCHER_RUNNING_1:
159 /* The did a "break" from the inner while loop. */
163 current_catcher->state = CATCHER_RUNNING;
166 current_catcher->state = CATCHER_ABORTING;
167 /* See also throw_exception. */
170 internal_error (__FILE__, __LINE__, _("bad switch"));
172 case CATCHER_ABORTING:
177 struct gdb_exception exception = *current_catcher->exception;
179 if (current_catcher->mask & RETURN_MASK (exception.reason))
181 /* Exit normally if this catcher can handle this
182 exception. The caller analyses the func return
187 /* The caller didn't request that the event be caught,
188 relay the event to the next containing
191 throw_exception (exception);
194 internal_error (__FILE__, __LINE__, _("bad state"));
197 internal_error (__FILE__, __LINE__, _("bad switch"));
202 exceptions_state_mc_action_iter (void)
204 return exceptions_state_mc (CATCH_ITER);
208 exceptions_state_mc_action_iter_1 (void)
210 return exceptions_state_mc (CATCH_ITER_1);
213 /* Return EXCEPTION to the nearest containing catch_errors(). */
216 throw_exception (struct gdb_exception exception)
218 struct thread_info *tp = NULL;
223 if (!ptid_equal (inferior_ptid, null_ptid))
224 tp = find_thread_ptid (inferior_ptid);
226 /* Perhaps it would be cleaner to do this via the cleanup chain (not sure
227 I can think of a reason why that is vital, though). */
229 bpstat_clear_actions (tp->stop_bpstat); /* Clear queued breakpoint commands */
231 disable_current_display ();
232 do_cleanups (ALL_CLEANUPS);
234 /* Jump to the containing catch_errors() call, communicating REASON
235 to that call via setjmp's return value. Note that REASON can't
236 be zero, by definition in defs.h. */
237 exceptions_state_mc (CATCH_THROWING);
238 *current_catcher->exception = exception;
239 EXCEPTIONS_SIGLONGJMP (current_catcher->buf, exception.reason);
242 static char *last_message;
245 deprecated_throw_reason (enum return_reason reason)
247 struct gdb_exception exception;
249 memset (&exception, 0, sizeof exception);
251 exception.reason = reason;
257 exception.error = GENERIC_ERROR;
260 internal_error (__FILE__, __LINE__, _("bad switch"));
263 throw_exception (exception);
269 struct serial *gdb_stdout_serial;
271 if (deprecated_error_begin_hook)
272 deprecated_error_begin_hook ();
273 target_terminal_ours ();
275 /* We want all output to appear now, before we print the error. We
276 have 3 levels of buffering we have to flush (it's possible that
277 some of these should be changed to flush the lower-level ones
280 /* 1. The _filtered buffer. */
283 /* 2. The stdio buffer. */
284 gdb_flush (gdb_stdout);
285 gdb_flush (gdb_stderr);
287 /* 3. The system-level buffer. */
288 gdb_stdout_serial = serial_fdopen (1);
289 if (gdb_stdout_serial)
291 serial_drain_output (gdb_stdout_serial);
292 serial_un_fdopen (gdb_stdout_serial);
295 annotate_error_begin ();
299 print_exception (struct ui_file *file, struct gdb_exception e)
301 /* KLUGE: cagney/2005-01-13: Write the string out one line at a time
302 as that way the MI's behavior is preserved. */
306 for (start = e.message; start != NULL; start = end)
308 end = strchr (start, '\n');
310 fputs_filtered (start, file);
314 ui_file_write (file, start, end - start);
317 fprintf_filtered (file, "\n");
319 /* Now append the annotation. */
326 /* Assume that these are all errors. */
330 internal_error (__FILE__, __LINE__, _("Bad switch."));
335 exception_print (struct ui_file *file, struct gdb_exception e)
337 if (e.reason < 0 && e.message != NULL)
340 print_exception (file, e);
345 exception_fprintf (struct ui_file *file, struct gdb_exception e,
346 const char *prefix, ...)
348 if (e.reason < 0 && e.message != NULL)
354 /* Print the prefix. */
355 va_start (args, prefix);
356 vfprintf_filtered (file, prefix, args);
359 print_exception (file, e);
364 print_any_exception (struct ui_file *file, const char *prefix,
365 struct gdb_exception e)
367 if (e.reason < 0 && e.message != NULL)
369 target_terminal_ours ();
370 wrap_here (""); /* Force out any buffered output */
371 gdb_flush (gdb_stdout);
372 annotate_error_begin ();
374 /* Print the prefix. */
375 if (prefix != NULL && prefix[0] != '\0')
376 fputs_filtered (prefix, file);
377 print_exception (file, e);
381 static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0)
382 throw_it (enum return_reason reason, enum errors error, const char *fmt,
385 struct gdb_exception e;
388 /* Save the message. Create the new message before deleting the
389 old, the new message may include the old message text. */
390 new_message = xstrvprintf (fmt, ap);
391 xfree (last_message);
392 last_message = new_message;
394 /* Create the exception. */
397 e.message = last_message;
399 /* Throw the exception. */
404 throw_verror (enum errors error, const char *fmt, va_list ap)
406 throw_it (RETURN_ERROR, error, fmt, ap);
410 throw_vfatal (const char *fmt, va_list ap)
412 throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap);
416 throw_error (enum errors error, const char *fmt, ...)
420 va_start (args, fmt);
421 throw_it (RETURN_ERROR, error, fmt, args);
425 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
426 handler. If an exception (enum return_reason) is thrown using
427 throw_exception() than all cleanups installed since
428 catch_exceptions() was entered are invoked, the (-ve) exception
429 value is then returned by catch_exceptions. If FUNC() returns
430 normally (with a positive or zero return value) then that value is
431 returned by catch_exceptions(). It is an internal_error() for
432 FUNC() to return a negative value.
434 See exceptions.h for further usage details.
436 Must not be called with immediate_quit in effect (bad things might
437 happen, say we got a signal in the middle of a memcpy to quit_return).
438 This is an OK restriction; with very few exceptions immediate_quit can
439 be replaced by judicious use of QUIT. */
441 /* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with
442 error() et.al. could maintain a set of flags that indicate the the
443 current state of each of the longjmp buffers. This would give the
444 longjmp code the chance to detect a longjmp botch (before it gets
445 to longjmperror()). Prior to 1999-11-05 this wasn't possible as
446 code also randomly used a SET_TOP_LEVEL macro that directly
447 initialize the longjmp buffers. */
450 catch_exceptions (struct ui_out *uiout,
451 catch_exceptions_ftype *func,
455 return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask);
459 catch_exception (struct ui_out *uiout,
460 catch_exception_ftype *func,
464 volatile struct gdb_exception exception;
466 TRY_CATCH (exception, mask)
468 (*func) (uiout, func_args);
474 catch_exceptions_with_msg (struct ui_out *uiout,
475 catch_exceptions_ftype *func,
480 volatile struct gdb_exception exception;
481 volatile int val = 0;
483 TRY_CATCH (exception, mask)
485 val = (*func) (uiout, func_args);
487 print_any_exception (gdb_stderr, NULL, exception);
488 gdb_assert (val >= 0);
489 gdb_assert (exception.reason <= 0);
490 if (exception.reason < 0)
492 /* If caller wants a copy of the low-level error message, make
493 one. This is used in the case of a silent error whereby the
494 caller may optionally want to issue the message. */
495 if (gdberrmsg != NULL)
497 if (exception.message != NULL)
498 *gdberrmsg = xstrdup (exception.message);
502 return exception.reason;
507 /* This function is superseded by catch_exceptions(). */
510 catch_errors (catch_errors_ftype *func, void *func_args, char *errstring,
513 volatile int val = 0;
514 volatile struct gdb_exception exception;
516 TRY_CATCH (exception, mask)
518 val = func (func_args);
520 print_any_exception (gdb_stderr, errstring, exception);
521 if (exception.reason != 0)
527 catch_command_errors (catch_command_errors_ftype * command,
528 char *arg, int from_tty, return_mask mask)
530 volatile struct gdb_exception e;
534 command (arg, from_tty);
536 print_any_exception (gdb_stderr, NULL, e);