gdb/inf-loop.c

   1 /* Handling of inferior events for the event loop for GDB, the GNU debugger.
   2    Copyright (C) 1999-2014 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"
  22 #include "infrun.h"
  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 #include "interps.h"
  33 #include "top.h"
  34 #include "observer.h"
  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       /* 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       {
  54         volatile struct gdb_exception ex;
  55
  56         TRY_CATCH (ex, RETURN_MASK_ALL)
  57           {
  58             fetch_inferior_event (client_data);
  59           }
  60         if (ex.reason < 0)
  61           {
  62             bpstat_clear_actions ();
  63             do_all_intermediate_continuations (1);
  64             do_all_continuations (1);
  65
  66             throw_exception (ex);
  67           }
  68       }
  69       break;
  70
  71     case INF_EXEC_COMPLETE:
  72       if (!non_stop)
  73         {
  74           /* Unregister the inferior from the event loop.  This is done
  75              so that when the inferior is not running we don't get
  76              distracted by spurious inferior output.  */
  77           if (target_has_execution)
  78             target_async (NULL, 0);
  79         }
  80
  81       /* Do all continuations associated with the whole inferior (not
  82          a particular thread).  */
  83       if (!ptid_equal (inferior_ptid, null_ptid))
  84         do_all_inferior_continuations (0);
  85
  86       /* If we were doing a multi-step (eg: step n, next n), but it
  87          got interrupted by a breakpoint, still do the pending
  88          continuations.  The continuation itself is responsible for
  89          distinguishing the cases.  The continuations are allowed to
  90          touch the inferior memory, e.g. to remove breakpoints, so run
  91          them before running breakpoint commands, which may resume the
  92          target.  */
  93       if (non_stop
  94           && target_has_execution
  95           && !ptid_equal (inferior_ptid, null_ptid))
  96         do_all_intermediate_continuations_thread (inferior_thread (), 0);
  97       else
  98         do_all_intermediate_continuations (0);
  99
 100       /* Always finish the previous command before running any
 101          breakpoint commands.  Any stop cancels the previous command.
 102          E.g. a "finish" or "step-n" command interrupted by an
 103          unrelated breakpoint is canceled.  */
 104       if (non_stop
 105           && target_has_execution
 106           && !ptid_equal (inferior_ptid, null_ptid))
 107         do_all_continuations_thread (inferior_thread (), 0);
 108       else
 109         do_all_continuations (0);
 110
 111       /* When running a command list (from a user command, say), these
 112          are only run when the command list is all done.  */
 113       if (interpreter_async)
 114         {
 115           volatile struct gdb_exception e;
 116
 117           check_frame_language_change ();
 118
 119           /* Don't propagate breakpoint commands errors.  Either we're
 120              stopping or some command resumes the inferior.  The user will
 121              be informed.  */
 122           TRY_CATCH (e, RETURN_MASK_ALL)
 123             {
 124               bpstat_do_actions ();
 125             }
 126           exception_print (gdb_stderr, e);
 127         }
 128       break;
 129
 130     case INF_EXEC_CONTINUE:
 131       /* Is there anything left to do for the command issued to
 132          complete?  */
 133
 134       if (non_stop)
 135         do_all_intermediate_continuations_thread (inferior_thread (), 0);
 136       else
 137         do_all_intermediate_continuations (0);
 138       break;
 139
 140     case INF_TIMER:
 141     default:
 142       printf_unfiltered (_("Event type not recognized.\n"));
 143       break;
 144     }
 145
 146   discard_cleanups (cleanup_if_error);
 147 }