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+/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
+
+ Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
+ 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software
+ Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include "defs.h"
+#include "exceptions.h"
+#include <setjmp.h>
+#include "breakpoint.h"
+#include "target.h"
+#include "inferior.h"
+#include "annotate.h"
+#include "ui-out.h"
+#include "gdb_assert.h"
+
+/* One should use catch_errors rather than manipulating these
+ directly. */
+#if defined(HAVE_SIGSETJMP)
+#define SIGJMP_BUF sigjmp_buf
+#define SIGSETJMP(buf) sigsetjmp((buf), 1)
+#define SIGLONGJMP(buf,val) siglongjmp((buf), (val))
+#else
+#define SIGJMP_BUF jmp_buf
+#define SIGSETJMP(buf) setjmp(buf)
+#define SIGLONGJMP(buf,val) longjmp((buf), (val))
+#endif
+
+/* Where to go for throw_exception(). */
+static SIGJMP_BUF *catch_return;
+
+/* Return for reason REASON to the nearest containing catch_errors(). */
+
+NORETURN void
+throw_exception (enum return_reason reason)
+{
+ quit_flag = 0;
+ immediate_quit = 0;
+
+ /* Perhaps it would be cleaner to do this via the cleanup chain (not sure
+ I can think of a reason why that is vital, though). */
+ bpstat_clear_actions (stop_bpstat); /* Clear queued breakpoint commands */
+
+ disable_current_display ();
+ do_cleanups (ALL_CLEANUPS);
+ if (target_can_async_p () && !target_executing)
+ do_exec_cleanups (ALL_CLEANUPS);
+ if (sync_execution)
+ do_exec_error_cleanups (ALL_CLEANUPS);
+
+ if (annotation_level > 1)
+ switch (reason)
+ {
+ case RETURN_QUIT:
+ annotate_quit ();
+ break;
+ case RETURN_ERROR:
+ annotate_error ();
+ break;
+ }
+
+ /* Jump to the containing catch_errors() call, communicating REASON
+ to that call via setjmp's return value. Note that REASON can't
+ be zero, by definition in defs.h. */
+
+ (NORETURN void) SIGLONGJMP (*catch_return, (int) reason);
+}
+
+/* Call FUNC() with args FUNC_UIOUT and FUNC_ARGS, catching any
+ errors. Set FUNC_CAUGHT to an ``enum return_reason'' if the
+ function is aborted (using throw_exception() or zero if the
+ function returns normally. Set FUNC_VAL to the value returned by
+ the function or 0 if the function was aborted.
+
+ Must not be called with immediate_quit in effect (bad things might
+ happen, say we got a signal in the middle of a memcpy to quit_return).
+ This is an OK restriction; with very few exceptions immediate_quit can
+ be replaced by judicious use of QUIT.
+
+ MASK specifies what to catch; it is normally set to
+ RETURN_MASK_ALL, if for no other reason than that the code which
+ calls catch_errors might not be set up to deal with a quit which
+ isn't caught. But if the code can deal with it, it generally
+ should be RETURN_MASK_ERROR, unless for some reason it is more
+ useful to abort only the portion of the operation inside the
+ catch_errors. Note that quit should return to the command line
+ fairly quickly, even if some further processing is being done. */
+
+/* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with
+ error() et.al. could maintain a set of flags that indicate the the
+ current state of each of the longjmp buffers. This would give the
+ longjmp code the chance to detect a longjmp botch (before it gets
+ to longjmperror()). Prior to 1999-11-05 this wasn't possible as
+ code also randomly used a SET_TOP_LEVEL macro that directly
+ initialize the longjmp buffers. */
+
+/* MAYBE: cagney/1999-11-05: Should the catch_errors and cleanups code
+ be consolidated into a single file instead of being distributed
+ between utils.c and top.c? */
+
+static void
+catcher (catch_exceptions_ftype *func,
+ struct ui_out *func_uiout,
+ void *func_args,
+ int *func_val,
+ enum return_reason *func_caught,
+ char *errstring,
+ char **gdberrmsg,
+ return_mask mask)
+{
+ SIGJMP_BUF *saved_catch;
+ SIGJMP_BUF catch;
+ struct cleanup *saved_cleanup_chain;
+ char *saved_error_pre_print;
+ char *saved_quit_pre_print;
+ struct ui_out *saved_uiout;
+
+ /* Return value from SIGSETJMP(): enum return_reason if error or
+ quit caught, 0 otherwise. */
+ int caught;
+
+ /* Return value from FUNC(): Hopefully non-zero. Explicitly set to
+ zero if an error quit was caught. */
+ int val;
+
+ /* Override error/quit messages during FUNC. */
+
+ saved_error_pre_print = error_pre_print;
+ saved_quit_pre_print = quit_pre_print;
+
+ if (mask & RETURN_MASK_ERROR)
+ error_pre_print = errstring;
+ if (mask & RETURN_MASK_QUIT)
+ quit_pre_print = errstring;
+
+ /* Override the global ``struct ui_out'' builder. */
+
+ saved_uiout = uiout;
+ uiout = func_uiout;
+
+ /* Prevent error/quit during FUNC from calling cleanups established
+ prior to here. */
+
+ saved_cleanup_chain = save_cleanups ();
+
+ /* Call FUNC, catching error/quit events. */
+
+ saved_catch = catch_return;
+ catch_return = &catch;
+ caught = SIGSETJMP (catch);
+ if (!caught)
+ val = (*func) (func_uiout, func_args);
+ else
+ {
+ val = 0;
+ /* If caller wants a copy of the low-level error message, make one.
+ This is used in the case of a silent error whereby the caller
+ may optionally want to issue the message. */
+ if (gdberrmsg)
+ *gdberrmsg = error_last_message ();
+ }
+ catch_return = saved_catch;
+
+ /* FIXME: cagney/1999-11-05: A correct FUNC implementation will
+ clean things up (restoring the cleanup chain) to the state they
+ were just prior to the call. Unfortunately, many FUNC's are not
+ that well behaved. This could be fixed by adding either a
+ do_cleanups call (to cover the problem) or an assertion check to
+ detect bad FUNCs code. */
+
+ /* Restore the cleanup chain, the error/quit messages, and the uiout
+ builder, to their original states. */
+
+ restore_cleanups (saved_cleanup_chain);
+
+ uiout = saved_uiout;
+
+ if (mask & RETURN_MASK_QUIT)
+ quit_pre_print = saved_quit_pre_print;
+ if (mask & RETURN_MASK_ERROR)
+ error_pre_print = saved_error_pre_print;
+
+ /* Return normally if no error/quit event occurred or this catcher
+ can handle this exception. The caller analyses the func return
+ values. */
+
+ if (!caught || (mask & RETURN_MASK (caught)))
+ {
+ *func_val = val;
+ *func_caught = caught;
+ return;
+ }
+
+ /* The caller didn't request that the event be caught, relay the
+ event to the next containing catch_errors(). */
+
+ throw_exception (caught);
+}
+
+int
+catch_exceptions (struct ui_out *uiout,
+ catch_exceptions_ftype *func,
+ void *func_args,
+ char *errstring,
+ return_mask mask)
+{
+ int val;
+ enum return_reason caught;
+ catcher (func, uiout, func_args, &val, &caught, errstring, NULL, mask);
+ gdb_assert (val >= 0);
+ gdb_assert (caught <= 0);
+ if (caught < 0)
+ return caught;
+ return val;
+}
+
+int
+catch_exceptions_with_msg (struct ui_out *uiout,
+ catch_exceptions_ftype *func,
+ void *func_args,
+ char *errstring,
+ char **gdberrmsg,
+ return_mask mask)
+{
+ int val;
+ enum return_reason caught;
+ catcher (func, uiout, func_args, &val, &caught, errstring, gdberrmsg, mask);
+ gdb_assert (val >= 0);
+ gdb_assert (caught <= 0);
+ if (caught < 0)
+ return caught;
+ return val;
+}
+
+struct catch_errors_args
+{
+ catch_errors_ftype *func;
+ void *func_args;
+};
+
+static int
+do_catch_errors (struct ui_out *uiout, void *data)
+{
+ struct catch_errors_args *args = data;
+ return args->func (args->func_args);
+}
+
+int
+catch_errors (catch_errors_ftype *func, void *func_args, char *errstring,
+ return_mask mask)
+{
+ int val;
+ enum return_reason caught;
+ struct catch_errors_args args;
+ args.func = func;
+ args.func_args = func_args;
+ catcher (do_catch_errors, uiout, &args, &val, &caught, errstring,
+ NULL, mask);
+ if (caught != 0)
+ return 0;
+ return val;
+}
+
+struct captured_command_args
+ {
+ catch_command_errors_ftype *command;
+ char *arg;
+ int from_tty;
+ };
+
+static int
+do_captured_command (void *data)
+{
+ struct captured_command_args *context = data;
+ context->command (context->arg, context->from_tty);
+ /* FIXME: cagney/1999-11-07: Technically this do_cleanups() call
+ isn't needed. Instead an assertion check could be made that
+ simply confirmed that the called function correctly cleaned up
+ after itself. Unfortunately, old code (prior to 1999-11-04) in
+ main.c was calling SET_TOP_LEVEL(), calling the command function,
+ and then *always* calling do_cleanups(). For the moment we
+ remain ``bug compatible'' with that old code.. */
+ do_cleanups (ALL_CLEANUPS);
+ return 1;
+}
+
+int
+catch_command_errors (catch_command_errors_ftype * command,
+ char *arg, int from_tty, return_mask mask)
+{
+ struct captured_command_args args;
+ args.command = command;
+ args.arg = arg;
+ args.from_tty = from_tty;
+ return catch_errors (do_captured_command, &args, "", mask);
+}