gdb/inf-loop.c

   1 /* Handling of inferior events for the event loop for GDB, the GNU debugger.
   2    Copyright (C) 1999, 2007, 2008, 2009, 2010, 2011
   3    Free Software Foundation, Inc.
   4    Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "inferior.h"           /* For fetch_inferior_event.  */
  23 #include "target.h"             /* For enum inferior_event_type.  */
  24 #include "event-loop.h"
  25 #include "event-top.h"
  26 #include "inf-loop.h"
  27 #include "remote.h"
  28 #include "exceptions.h"
  29 #include "language.h"
  30 #include "gdbthread.h"
  31 #include "continuations.h"
  32
  33 static int fetch_inferior_event_wrapper (gdb_client_data client_data);
  34
  35 /* General function to handle events in the inferior.  So far it just
  36    takes care of detecting errors reported by select() or poll(),
  37    otherwise it assumes that all is OK, and goes on reading data from
  38    the fd.  This however may not always be what we want to do.  */
  39 void
  40 inferior_event_handler (enum inferior_event_type event_type,
  41                         gdb_client_data client_data)
  42 {
  43   struct gdb_exception e;
  44   int was_sync = 0;
  45   struct cleanup *cleanup_if_error = make_bpstat_clear_actions_cleanup ();
  46
  47   switch (event_type)
  48     {
  49     case INF_REG_EVENT:
  50       /* Use catch errors for now, until the inner layers of
  51          fetch_inferior_event (i.e. readchar) can return meaningful
  52          error status.  If an error occurs while getting an event from
  53          the target, just cancel the current command.  */
  54       if (!catch_errors (fetch_inferior_event_wrapper,
  55                          client_data, "", RETURN_MASK_ALL))
  56         {
  57           bpstat_clear_actions ();
  58           do_all_intermediate_continuations (1);
  59           do_all_continuations (1);
  60           async_enable_stdin ();
  61           display_gdb_prompt (0);
  62         }
  63       break;
  64
  65     case INF_EXEC_COMPLETE:
  66
  67       if (!non_stop)
  68         {
  69           /* Unregister the inferior from the event loop.  This is done
  70              so that when the inferior is not running we don't get
  71              distracted by spurious inferior output.  */
  72           if (target_has_execution)
  73             target_async (NULL, 0);
  74         }
  75
  76       /* The call to async_enable_stdin below resets 'sync_execution'.
  77          However, if sync_execution is 1 now, we also need to show the
  78          prompt below, so save the current value.  */
  79       was_sync = sync_execution;
  80       async_enable_stdin ();
  81
  82       /* Do all continuations associated with the whole inferior (not
  83          a particular thread).  */
  84       if (!ptid_equal (inferior_ptid, null_ptid))
  85         do_all_inferior_continuations (0);
  86
  87       /* If we were doing a multi-step (eg: step n, next n), but it
  88          got interrupted by a breakpoint, still do the pending
  89          continuations.  The continuation itself is responsible for
  90          distinguishing the cases.  The continuations are allowed to
  91          touch the inferior memory, e.g. to remove breakpoints, so run
  92          them before running breakpoint commands, which may resume the
  93          target.  */
  94       if (non_stop
  95           && target_has_execution
  96           && !ptid_equal (inferior_ptid, null_ptid))
  97         do_all_intermediate_continuations_thread (inferior_thread (), 0);
  98       else
  99         do_all_intermediate_continuations (0);
 100
 101       /* Always finish the previous command before running any
 102          breakpoint commands.  Any stop cancels the previous command.
 103          E.g. a "finish" or "step-n" command interrupted by an
 104          unrelated breakpoint is canceled.  */
 105       if (non_stop
 106           && target_has_execution
 107           && !ptid_equal (inferior_ptid, null_ptid))
 108         do_all_continuations_thread (inferior_thread (), 0);
 109       else
 110         do_all_continuations (0);
 111
 112       if (info_verbose
 113           && current_language != expected_language
 114           && language_mode == language_mode_auto)
 115         language_info (1);      /* Print what changed.  */
 116
 117       /* Don't propagate breakpoint commands errors.  Either we're
 118          stopping or some command resumes the inferior.  The user will
 119          be informed.  */
 120       TRY_CATCH (e, RETURN_MASK_ALL)
 121         {
 122           bpstat_do_actions ();
 123         }
 124       exception_print (gdb_stderr, e);
 125
 126       if (!was_sync
 127           && exec_done_display_p
 128           && (ptid_equal (inferior_ptid, null_ptid)
 129               || !is_running (inferior_ptid)))
 130         printf_unfiltered (_("completed.\n"));
 131       break;
 132
 133     case INF_EXEC_CONTINUE:
 134       /* Is there anything left to do for the command issued to
 135          complete?  */
 136
 137       if (non_stop)
 138         do_all_intermediate_continuations_thread (inferior_thread (), 0);
 139       else
 140         do_all_intermediate_continuations (0);
 141       break;
 142
 143     case INF_TIMER:
 144     default:
 145       printf_unfiltered (_("Event type not recognized.\n"));
 146       break;
 147     }
 148
 149   discard_cleanups (cleanup_if_error);
 150 }
 151
 152 static int
 153 fetch_inferior_event_wrapper (gdb_client_data client_data)
 154 {
 155   fetch_inferior_event (client_data);
 156   return 1;
 157 }