gdb/inf-loop.c

   1 /* Handling of inferior events for the event loop for GDB, the GNU debugger.
   2    Copyright (C) 1999-2013 Free Software Foundation, Inc.
   3    Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
   4
   5    This file is part of GDB.
   6
   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.
  11
  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.
  16
  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/>.  */
  19
  20 #include "defs.h"
  21 #include "inferior.h"           /* For fetch_inferior_event.  */
  22 #include "target.h"             /* For enum inferior_event_type.  */
  23 #include "event-loop.h"
  24 #include "event-top.h"
  25 #include "inf-loop.h"
  26 #include "remote.h"
  27 #include "exceptions.h"
  28 #include "language.h"
  29 #include "gdbthread.h"
  30 #include "continuations.h"
  31 #include "interps.h"
  32 #include "top.h"
  33
  34 static int fetch_inferior_event_wrapper (gdb_client_data client_data);
  35
  36 /* General function to handle events in the inferior.  So far it just
  37    takes care of detecting errors reported by select() or poll(),
  38    otherwise it assumes that all is OK, and goes on reading data from
  39    the fd.  This however may not always be what we want to do.  */
  40 void
  41 inferior_event_handler (enum inferior_event_type event_type,
  42                         gdb_client_data client_data)
  43 {
  44   struct cleanup *cleanup_if_error = make_bpstat_clear_actions_cleanup ();
  45
  46   switch (event_type)
  47     {
  48     case INF_REG_EVENT:
  49       /* Use catch errors for now, until the inner layers of
  50          fetch_inferior_event (i.e. readchar) can return meaningful
  51          error status.  If an error occurs while getting an event from
  52          the target, just cancel the current command.  */
  53       if (!catch_errors (fetch_inferior_event_wrapper,
  54                          client_data, "", RETURN_MASK_ALL))
  55         {
  56           bpstat_clear_actions ();
  57           do_all_intermediate_continuations (1);
  58           do_all_continuations (1);
  59           async_enable_stdin ();
  60           display_gdb_prompt (0);
  61         }
  62       break;
  63
  64     case INF_EXEC_COMPLETE:
  65       if (!non_stop)
  66         {
  67           /* Unregister the inferior from the event loop.  This is done
  68              so that when the inferior is not running we don't get
  69              distracted by spurious inferior output.  */
  70           if (target_has_execution)
  71             target_async (NULL, 0);
  72         }
  73
  74       /* Do all continuations associated with the whole inferior (not
  75          a particular thread).  */
  76       if (!ptid_equal (inferior_ptid, null_ptid))
  77         do_all_inferior_continuations (0);
  78
  79       /* If we were doing a multi-step (eg: step n, next n), but it
  80          got interrupted by a breakpoint, still do the pending
  81          continuations.  The continuation itself is responsible for
  82          distinguishing the cases.  The continuations are allowed to
  83          touch the inferior memory, e.g. to remove breakpoints, so run
  84          them before running breakpoint commands, which may resume the
  85          target.  */
  86       if (non_stop
  87           && target_has_execution
  88           && !ptid_equal (inferior_ptid, null_ptid))
  89         do_all_intermediate_continuations_thread (inferior_thread (), 0);
  90       else
  91         do_all_intermediate_continuations (0);
  92
  93       /* Always finish the previous command before running any
  94          breakpoint commands.  Any stop cancels the previous command.
  95          E.g. a "finish" or "step-n" command interrupted by an
  96          unrelated breakpoint is canceled.  */
  97       if (non_stop
  98           && target_has_execution
  99           && !ptid_equal (inferior_ptid, null_ptid))
 100         do_all_continuations_thread (inferior_thread (), 0);
 101       else
 102         do_all_continuations (0);
 103
 104       /* When running a command list (from a user command, say), these
 105          are only run when the command list is all done.  */
 106       if (interpreter_async)
 107         {
 108           volatile struct gdb_exception e;
 109
 110           check_frame_language_change ();
 111
 112           /* Don't propagate breakpoint commands errors.  Either we're
 113              stopping or some command resumes the inferior.  The user will
 114              be informed.  */
 115           TRY_CATCH (e, RETURN_MASK_ALL)
 116             {
 117               bpstat_do_actions ();
 118             }
 119           exception_print (gdb_stderr, e);
 120         }
 121       break;
 122
 123     case INF_EXEC_CONTINUE:
 124       /* Is there anything left to do for the command issued to
 125          complete?  */
 126
 127       if (non_stop)
 128         do_all_intermediate_continuations_thread (inferior_thread (), 0);
 129       else
 130         do_all_intermediate_continuations (0);
 131       break;
 132
 133     case INF_TIMER:
 134     default:
 135       printf_unfiltered (_("Event type not recognized.\n"));
 136       break;
 137     }
 138
 139   discard_cleanups (cleanup_if_error);
 140 }
 141
 142 static int
 143 fetch_inferior_event_wrapper (gdb_client_data client_data)
 144 {
 145   fetch_inferior_event (client_data);
 146   return 1;
 147 }