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
;
107 current_catcher
= old_catcher
->prev
;
109 /* Restore the cleanup chain, the error/quit messages, and the uiout
110 builder, to their original states. */
112 restore_cleanups (old_catcher
->saved_cleanup_chain
);
114 uiout
= old_catcher
->saved_uiout
;
119 /* Catcher state machine. Returns non-zero if the m/c should be run
120 again, zero if it should abort. */
123 exceptions_state_mc (enum catcher_action action
)
125 switch (current_catcher
->state
)
127 case CATCHER_CREATED
:
131 /* Allow the code to run the catcher. */
132 current_catcher
->state
= CATCHER_RUNNING
;
135 internal_error (__FILE__
, __LINE__
, _("bad state"));
137 case CATCHER_RUNNING
:
141 /* No error/quit has occured. Just clean up. */
145 current_catcher
->state
= CATCHER_RUNNING_1
;
148 current_catcher
->state
= CATCHER_ABORTING
;
149 /* See also throw_exception. */
152 internal_error (__FILE__
, __LINE__
, _("bad switch"));
154 case CATCHER_RUNNING_1
:
158 /* The did a "break" from the inner while loop. */
162 current_catcher
->state
= CATCHER_RUNNING
;
165 current_catcher
->state
= CATCHER_ABORTING
;
166 /* See also throw_exception. */
169 internal_error (__FILE__
, __LINE__
, _("bad switch"));
171 case CATCHER_ABORTING
:
176 struct gdb_exception exception
= *current_catcher
->exception
;
177 if (current_catcher
->mask
& RETURN_MASK (exception
.reason
))
179 /* Exit normally if this catcher can handle this
180 exception. The caller analyses the func return
185 /* The caller didn't request that the event be caught,
186 relay the event to the next containing
189 throw_exception (exception
);
192 internal_error (__FILE__
, __LINE__
, _("bad state"));
195 internal_error (__FILE__
, __LINE__
, _("bad switch"));
200 exceptions_state_mc_action_iter (void)
202 return exceptions_state_mc (CATCH_ITER
);
206 exceptions_state_mc_action_iter_1 (void)
208 return exceptions_state_mc (CATCH_ITER_1
);
211 /* Return EXCEPTION to the nearest containing catch_errors(). */
214 throw_exception (struct gdb_exception exception
)
216 struct thread_info
*tp
= NULL
;
221 if (!ptid_equal (inferior_ptid
, null_ptid
))
222 tp
= find_thread_ptid (inferior_ptid
);
224 /* Perhaps it would be cleaner to do this via the cleanup chain (not sure
225 I can think of a reason why that is vital, though). */
227 bpstat_clear_actions (tp
->stop_bpstat
); /* Clear queued breakpoint commands */
229 disable_current_display ();
230 do_cleanups (ALL_CLEANUPS
);
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. */
235 exceptions_state_mc (CATCH_THROWING
);
236 *current_catcher
->exception
= exception
;
237 EXCEPTIONS_SIGLONGJMP (current_catcher
->buf
, exception
.reason
);
240 static char *last_message
;
243 deprecated_throw_reason (enum return_reason reason
)
245 struct gdb_exception exception
;
246 memset (&exception
, 0, sizeof exception
);
248 exception
.reason
= reason
;
254 exception
.error
= GENERIC_ERROR
;
257 internal_error (__FILE__
, __LINE__
, _("bad switch"));
260 throw_exception (exception
);
266 struct serial
*gdb_stdout_serial
;
268 if (deprecated_error_begin_hook
)
269 deprecated_error_begin_hook ();
270 target_terminal_ours ();
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
277 /* 1. The _filtered buffer. */
280 /* 2. The stdio buffer. */
281 gdb_flush (gdb_stdout
);
282 gdb_flush (gdb_stderr
);
284 /* 3. The system-level buffer. */
285 gdb_stdout_serial
= serial_fdopen (1);
286 if (gdb_stdout_serial
)
288 serial_drain_output (gdb_stdout_serial
);
289 serial_un_fdopen (gdb_stdout_serial
);
292 annotate_error_begin ();
296 print_exception (struct ui_file
*file
, struct gdb_exception e
)
298 /* KLUGE: cagney/2005-01-13: Write the string out one line at a time
299 as that way the MI's behavior is preserved. */
302 for (start
= e
.message
; start
!= NULL
; start
= end
)
304 end
= strchr (start
, '\n');
306 fputs_filtered (start
, file
);
310 ui_file_write (file
, start
, end
- start
);
313 fprintf_filtered (file
, "\n");
315 /* Now append the annotation. */
322 /* Assume that these are all errors. */
326 internal_error (__FILE__
, __LINE__
, _("Bad switch."));
331 exception_print (struct ui_file
*file
, struct gdb_exception e
)
333 if (e
.reason
< 0 && e
.message
!= NULL
)
336 print_exception (file
, e
);
341 exception_fprintf (struct ui_file
*file
, struct gdb_exception e
,
342 const char *prefix
, ...)
344 if (e
.reason
< 0 && e
.message
!= NULL
)
350 /* Print the prefix. */
351 va_start (args
, prefix
);
352 vfprintf_filtered (file
, prefix
, args
);
355 print_exception (file
, e
);
360 print_any_exception (struct ui_file
*file
, const char *prefix
,
361 struct gdb_exception e
)
363 if (e
.reason
< 0 && e
.message
!= NULL
)
365 target_terminal_ours ();
366 wrap_here (""); /* Force out any buffered output */
367 gdb_flush (gdb_stdout
);
368 annotate_error_begin ();
370 /* Print the prefix. */
371 if (prefix
!= NULL
&& prefix
[0] != '\0')
372 fputs_filtered (prefix
, file
);
373 print_exception (file
, e
);
377 NORETURN
static void ATTR_NORETURN
ATTR_FORMAT (printf
, 3, 0)
378 throw_it (enum return_reason reason
, enum errors error
, const char *fmt
,
381 struct gdb_exception e
;
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
);
387 xfree (last_message
);
388 last_message
= new_message
;
390 /* Create the exception. */
393 e
.message
= last_message
;
395 /* Throw the exception. */
400 throw_verror (enum errors error
, const char *fmt
, va_list ap
)
402 throw_it (RETURN_ERROR
, error
, fmt
, ap
);
406 throw_vfatal (const char *fmt
, va_list ap
)
408 throw_it (RETURN_QUIT
, GDB_NO_ERROR
, fmt
, ap
);
412 throw_error (enum errors error
, const char *fmt
, ...)
415 va_start (args
, fmt
);
416 throw_it (RETURN_ERROR
, error
, fmt
, args
);
420 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
421 handler. If an exception (enum return_reason) is thrown using
422 throw_exception() than all cleanups installed since
423 catch_exceptions() was entered are invoked, the (-ve) exception
424 value is then returned by catch_exceptions. If FUNC() returns
425 normally (with a positive or zero return value) then that value is
426 returned by catch_exceptions(). It is an internal_error() for
427 FUNC() to return a negative value.
429 See exceptions.h for further usage details.
431 Must not be called with immediate_quit in effect (bad things might
432 happen, say we got a signal in the middle of a memcpy to quit_return).
433 This is an OK restriction; with very few exceptions immediate_quit can
434 be replaced by judicious use of QUIT. */
436 /* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with
437 error() et.al. could maintain a set of flags that indicate the the
438 current state of each of the longjmp buffers. This would give the
439 longjmp code the chance to detect a longjmp botch (before it gets
440 to longjmperror()). Prior to 1999-11-05 this wasn't possible as
441 code also randomly used a SET_TOP_LEVEL macro that directly
442 initialize the longjmp buffers. */
445 catch_exceptions (struct ui_out
*uiout
,
446 catch_exceptions_ftype
*func
,
450 return catch_exceptions_with_msg (uiout
, func
, func_args
, NULL
, mask
);
454 catch_exception (struct ui_out
*uiout
,
455 catch_exception_ftype
*func
,
459 volatile struct gdb_exception exception
;
460 TRY_CATCH (exception
, mask
)
462 (*func
) (uiout
, func_args
);
468 catch_exceptions_with_msg (struct ui_out
*uiout
,
469 catch_exceptions_ftype
*func
,
474 volatile struct gdb_exception exception
;
475 volatile int val
= 0;
476 TRY_CATCH (exception
, mask
)
478 val
= (*func
) (uiout
, func_args
);
480 print_any_exception (gdb_stderr
, NULL
, exception
);
481 gdb_assert (val
>= 0);
482 gdb_assert (exception
.reason
<= 0);
483 if (exception
.reason
< 0)
485 /* If caller wants a copy of the low-level error message, make
486 one. This is used in the case of a silent error whereby the
487 caller may optionally want to issue the message. */
488 if (gdberrmsg
!= NULL
)
490 if (exception
.message
!= NULL
)
491 *gdberrmsg
= xstrdup (exception
.message
);
495 return exception
.reason
;
500 /* This function is superseded by catch_exceptions(). */
503 catch_errors (catch_errors_ftype
*func
, void *func_args
, char *errstring
,
506 volatile int val
= 0;
507 volatile struct gdb_exception exception
;
508 TRY_CATCH (exception
, mask
)
510 val
= func (func_args
);
512 print_any_exception (gdb_stderr
, errstring
, exception
);
513 if (exception
.reason
!= 0)
519 catch_command_errors (catch_command_errors_ftype
* command
,
520 char *arg
, int from_tty
, return_mask mask
)
522 volatile struct gdb_exception e
;
525 command (arg
, from_tty
);
527 print_any_exception (gdb_stderr
, NULL
, e
);