gdb/exceptions.c - gdb

Global variables defined

Functions defined

Source code

  1. /* Exception (throw catch) mechanism, for GDB, the GNU debugger.

  3.    Copyright (C) 1986-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  7.    This program is free software; you can redistribute it and/or modify
  8.    it under the terms of the GNU General Public License as published by
  9.    the Free Software Foundation; either version 3 of the License, or
  10.    (at your option) any later version.

  12.    This program is distributed in the hope that it will be useful,
  13.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15.    GNU General Public License for more details.

  17.    You should have received a copy of the GNU General Public License
  18.    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

  20. #include "defs.h"
  21. #include "exceptions.h"
  22. #include "breakpoint.h"
  23. #include "target.h"
  24. #include "inferior.h"
  25. #include "annotate.h"
  26. #include "ui-out.h"
  27. #include "serial.h"
  28. #include "gdbthread.h"

  30. ‌const struct gdb_exception exception_none = { 0, GDB_NO_ERROR, NULL };

  32. void
  33. ‌prepare_to_throw_exception (void)
  34. {
  35.   clear_quit_flag ();
  36.   immediate_quit = 0;
  37. }

  39. static void
  40. ‌print_flush (void)
  41. {
  42.   struct serial *gdb_stdout_serial;

  44.   if (deprecated_error_begin_hook)
  45.     deprecated_error_begin_hook ();

  47.   if (target_supports_terminal_ours ())
  48.     target_terminal_ours ();

  50.   /* We want all output to appear now, before we print the error.  We
  51.      have 3 levels of buffering we have to flush (it's possible that
  52.      some of these should be changed to flush the lower-level ones
  53.      too):  */

  55.   /* 1.  The _filtered buffer.  */
  56.   if (filtered_printing_initialized ())
  57.     wrap_here ("");

  59.   /* 2.  The stdio buffer.  */
  60.   gdb_flush (gdb_stdout);
  61.   gdb_flush (gdb_stderr);

  63.   /* 3.  The system-level buffer.  */
  64.   gdb_stdout_serial = serial_fdopen (1);
  65.   if (gdb_stdout_serial)
  66.     {
  67.       serial_drain_output (gdb_stdout_serial);
  68.       serial_un_fdopen (gdb_stdout_serial);
  69.     }

  71.   annotate_error_begin ();
  72. }

  74. static void
  75. ‌print_exception (struct ui_file *file, struct gdb_exception e)
  76. {
  77.   /* KLUGE: cagney/2005-01-13: Write the string out one line at a time
  78.      as that way the MI's behavior is preserved.  */
  79.   const char *start;
  80.   const char *end;

  82.   for (start = e.message; start != NULL; start = end)
  83.     {
  84.       end = strchr (start, '\n');
  85.       if (end == NULL)
  86.         fputs_filtered (start, file);
  87.       else
  88.         {
  89.           end++;
  90.           ui_file_write (file, start, end - start);
  91.         }
  92.     }
  93.   fprintf_filtered (file, "\n");

  95.   /* Now append the annotation.  */
  96.   switch (e.reason)
  97.     {
  98.     case RETURN_QUIT:
  99.       annotate_quit ();
  100.       break;
  101.     case RETURN_ERROR:
  102.       /* Assume that these are all errors.  */
  103.       annotate_error ();
  104.       break;
  105.     default:
  106.       internal_error (__FILE__, __LINE__, _("Bad switch."));
  107.     }
  108. }

  110. void
  111. ‌exception_print (struct ui_file *file, struct gdb_exception e)
  112. {
  113.   if (e.reason < 0 && e.message != NULL)
  114.     {
  115.       print_flush ();
  116.       print_exception (file, e);
  117.     }
  118. }

  120. void
  121. ‌exception_fprintf (struct ui_file *file, struct gdb_exception e,
  122.                    const char *prefix, ...)
  123. {
  124.   if (e.reason < 0 && e.message != NULL)
  125.     {
  126.       va_list args;

  128.       print_flush ();

  130.       /* Print the prefix.  */
  131.       va_start (args, prefix);
  132.       vfprintf_filtered (file, prefix, args);
  133.       va_end (args);

  135.       print_exception (file, e);
  136.     }
  137. }

  139. /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
  140.    handler.  If an exception (enum return_reason) is thrown using
  141.    throw_exception() than all cleanups installed since
  142.    catch_exceptions() was entered are invoked, the (-ve) exception
  143.    value is then returned by catch_exceptions.  If FUNC() returns
  144.    normally (with a positive or zero return value) then that value is
  145.    returned by catch_exceptions().  It is an internal_error() for
  146.    FUNC() to return a negative value.

  148.    See exceptions.h for further usage details.

  150.    Must not be called with immediate_quit in effect (bad things might
  151.    happen, say we got a signal in the middle of a memcpy to quit_return).
  152.    This is an OK restriction; with very few exceptions immediate_quit can
  153.    be replaced by judicious use of QUIT.  */

  155. /* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with
  156.    error() et al. could maintain a set of flags that indicate the
  157.    current state of each of the longjmp buffers.  This would give the
  158.    longjmp code the chance to detect a longjmp botch (before it gets
  159.    to longjmperror()).  Prior to 1999-11-05 this wasn't possible as
  160.    code also randomly used a SET_TOP_LEVEL macro that directly
  161.    initialized the longjmp buffers.  */

  163. int
  164. ‌catch_exceptions (struct ui_out *uiout,
  165.                   catch_exceptions_ftype *func,
  166.                   void *func_args,
  167.                   return_mask mask)
  168. {
  169.   return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask);
  170. }

  172. int
  173. ‌catch_exceptions_with_msg (struct ui_out *func_uiout,
  174.                              catch_exceptions_ftype *func,
  175.                              void *func_args,
  176.                            char **gdberrmsg,
  177.                              return_mask mask)
  178. {
  179.   volatile struct gdb_exception exception;
  180.   volatile int val = 0;
  181.   struct ui_out *saved_uiout;

  183.   /* Save and override the global ``struct ui_out'' builder.  */
  184.   saved_uiout = current_uiout;
  185.   current_uiout = func_uiout;

  187.   TRY_CATCH (exception, RETURN_MASK_ALL)
  188.     {
  189.       val = (*func) (current_uiout, func_args);
  190.     }

  192.   /* Restore the global builder.  */
  193.   current_uiout = saved_uiout;

  195.   if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0)
  196.     {
  197.       /* The caller didn't request that the event be caught.
  198.          Rethrow.  */
  199.       throw_exception (exception);
  200.     }

  202.   exception_print (gdb_stderr, exception);
  203.   gdb_assert (val >= 0);
  204.   gdb_assert (exception.reason <= 0);
  205.   if (exception.reason < 0)
  206.     {
  207.       /* If caller wants a copy of the low-level error message, make
  208.          one.  This is used in the case of a silent error whereby the
  209.          caller may optionally want to issue the message.  */
  210.       if (gdberrmsg != NULL)
  211.         {
  212.           if (exception.message != NULL)
  213.             *gdberrmsg = xstrdup (exception.message);
  214.           else
  215.             *gdberrmsg = NULL;
  216.         }
  217.       return exception.reason;
  218.     }
  219.   return val;
  220. }

  222. /* This function is superseded by catch_exceptions().  */

  224. int
  225. ‌catch_errors (catch_errors_ftype *func, void *func_args, char *errstring,
  226.               return_mask mask)
  227. {
  228.   volatile int val = 0;
  229.   volatile struct gdb_exception exception;
  230.   struct ui_out *saved_uiout;

  232.   /* Save the global ``struct ui_out'' builder.  */
  233.   saved_uiout = current_uiout;

  235.   TRY_CATCH (exception, RETURN_MASK_ALL)
  236.     {
  237.       val = func (func_args);
  238.     }

  240.   /* Restore the global builder.  */
  241.   current_uiout = saved_uiout;

  243.   if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0)
  244.     {
  245.       /* The caller didn't request that the event be caught.
  246.          Rethrow.  */
  247.       throw_exception (exception);
  248.     }

  250.   exception_fprintf (gdb_stderr, exception, "%s", errstring);
  251.   if (exception.reason != 0)
  252.     return 0;
  253.   return val;
  254. }