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 static int fetch_inferior_event_wrapper (gdb_client_data client_data);
  37
  38 /* General function to handle events in the inferior.  So far it just
  39    takes care of detecting errors reported by select() or poll(),
  40    otherwise it assumes that all is OK, and goes on reading data from
  41    the fd.  This however may not always be what we want to do.  */
  42 void
  43 inferior_event_handler (enum inferior_event_type event_type,
  44                         gdb_client_data client_data)
  45 {
  46   struct cleanup *cleanup_if_error = make_bpstat_clear_actions_cleanup ();
  47
  48   switch (event_type)
  49     {
  50     case INF_REG_EVENT:
  51       /* Use catch errors for now, until the inner layers of
  52          fetch_inferior_event (i.e. readchar) can return meaningful
  53          error status.  If an error occurs while getting an event from
  54          the target, just cancel the current command.  */
  55       if (!catch_errors (fetch_inferior_event_wrapper,
  56                          client_data, "", RETURN_MASK_ALL))
  57         {
  58           bpstat_clear_actions ();
  59           do_all_intermediate_continuations (1);
  60           do_all_continuations (1);
  61           async_enable_stdin ();
  62           observer_notify_command_error ();
  63         }
  64       break;
  65
  66     case INF_EXEC_COMPLETE:
  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       /* Do all continuations associated with the whole inferior (not
  77          a particular thread).  */
  78       if (!ptid_equal (inferior_ptid, null_ptid))
  79         do_all_inferior_continuations (0);
  80
  81       /* If we were doing a multi-step (eg: step n, next n), but it
  82          got interrupted by a breakpoint, still do the pending
  83          continuations.  The continuation itself is responsible for
  84          distinguishing the cases.  The continuations are allowed to
  85          touch the inferior memory, e.g. to remove breakpoints, so run
  86          them before running breakpoint commands, which may resume the
  87          target.  */
  88       if (non_stop
  89           && target_has_execution
  90           && !ptid_equal (inferior_ptid, null_ptid))
  91         do_all_intermediate_continuations_thread (inferior_thread (), 0);
  92       else
  93         do_all_intermediate_continuations (0);
  94
  95       /* Always finish the previous command before running any
  96          breakpoint commands.  Any stop cancels the previous command.
  97          E.g. a "finish" or "step-n" command interrupted by an
  98          unrelated breakpoint is canceled.  */
  99       if (non_stop
 100           && target_has_execution
 101           && !ptid_equal (inferior_ptid, null_ptid))
 102         do_all_continuations_thread (inferior_thread (), 0);
 103       else
 104         do_all_continuations (0);
 105
 106       /* When running a command list (from a user command, say), these
 107          are only run when the command list is all done.  */
 108       if (interpreter_async)
 109         {
 110           volatile struct gdb_exception e;
 111
 112           check_frame_language_change ();
 113
 114           /* Don't propagate breakpoint commands errors.  Either we're
 115              stopping or some command resumes the inferior.  The user will
 116              be informed.  */
 117           TRY_CATCH (e, RETURN_MASK_ALL)
 118             {
 119               bpstat_do_actions ();
 120             }
 121           exception_print (gdb_stderr, e);
 122         }
 123       break;
 124
 125     case INF_EXEC_CONTINUE:
 126       /* Is there anything left to do for the command issued to
 127          complete?  */
 128
 129       if (non_stop)
 130         do_all_intermediate_continuations_thread (inferior_thread (), 0);
 131       else
 132         do_all_intermediate_continuations (0);
 133       break;
 134
 135     case INF_TIMER:
 136     default:
 137       printf_unfiltered (_("Event type not recognized.\n"));
 138       break;
 139     }
 140
 141   discard_cleanups (cleanup_if_error);
 142 }
 143
 144 static int
 145 fetch_inferior_event_wrapper (gdb_client_data client_data)
 146 {
 147   fetch_inferior_event (client_data);
 148   return 1;
 149 }