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 "language.h"
  29 #include "gdbthread.h"
  30 #include "continuations.h"
  31 #include "interps.h"
  32 #include "top.h"
  33 #include "observer.h"
  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 cleanup *cleanup_if_error = make_bpstat_clear_actions_cleanup ();
  44
  45   switch (event_type)
  46     {
  47     case INF_REG_EVENT:
  48       /* Catch errors for now, until the inner layers of
  49          fetch_inferior_event (i.e. readchar) can return meaningful
  50          error status.  If an error occurs while getting an event from
  51          the target, just cancel the current command.  */
  52       {
  53         volatile struct gdb_exception ex;
  54
  55         TRY_CATCH (ex, RETURN_MASK_ALL)
  56           {
  57             fetch_inferior_event (client_data);
  58           }
  59         if (ex.reason < 0)
  60           {
  61             bpstat_clear_actions ();
  62             do_all_intermediate_continuations (1);
  63             do_all_continuations (1);
  64
  65             throw_exception (ex);
  66           }
  67       }
  68       break;
  69
  70     case INF_EXEC_COMPLETE:
  71       if (!non_stop)
  72         {
  73           /* Unregister the inferior from the event loop.  This is done
  74              so that when the inferior is not running we don't get
  75              distracted by spurious inferior output.  */
  76           if (target_has_execution)
  77             target_async (NULL, 0);
  78         }
  79
  80       /* Do all continuations associated with the whole inferior (not
  81          a particular thread).  */
  82       if (!ptid_equal (inferior_ptid, null_ptid))
  83         do_all_inferior_continuations (0);
  84
  85       /* If we were doing a multi-step (eg: step n, next n), but it
  86          got interrupted by a breakpoint, still do the pending
  87          continuations.  The continuation itself is responsible for
  88          distinguishing the cases.  The continuations are allowed to
  89          touch the inferior memory, e.g. to remove breakpoints, so run
  90          them before running breakpoint commands, which may resume the
  91          target.  */
  92       if (non_stop
  93           && target_has_execution
  94           && !ptid_equal (inferior_ptid, null_ptid))
  95         do_all_intermediate_continuations_thread (inferior_thread (), 0);
  96       else
  97         do_all_intermediate_continuations (0);
  98
  99       /* Always finish the previous command before running any
 100          breakpoint commands.  Any stop cancels the previous command.
 101          E.g. a "finish" or "step-n" command interrupted by an
 102          unrelated breakpoint is canceled.  */
 103       if (non_stop
 104           && target_has_execution
 105           && !ptid_equal (inferior_ptid, null_ptid))
 106         do_all_continuations_thread (inferior_thread (), 0);
 107       else
 108         do_all_continuations (0);
 109
 110       /* When running a command list (from a user command, say), these
 111          are only run when the command list is all done.  */
 112       if (interpreter_async)
 113         {
 114           volatile struct gdb_exception e;
 115
 116           check_frame_language_change ();
 117
 118           /* Don't propagate breakpoint commands errors.  Either we're
 119              stopping or some command resumes the inferior.  The user will
 120              be informed.  */
 121           TRY_CATCH (e, RETURN_MASK_ALL)
 122             {
 123               bpstat_do_actions ();
 124             }
 125           exception_print (gdb_stderr, e);
 126         }
 127       break;
 128
 129     case INF_EXEC_CONTINUE:
 130       /* Is there anything left to do for the command issued to
 131          complete?  */
 132
 133       if (non_stop)
 134         do_all_intermediate_continuations_thread (inferior_thread (), 0);
 135       else
 136         do_all_intermediate_continuations (0);
 137       break;
 138
 139     case INF_TIMER:
 140     default:
 141       printf_unfiltered (_("Event type not recognized.\n"));
 142       break;
 143     }
 144
 145   discard_cleanups (cleanup_if_error);
 146 }