binutils-gdb/gdb/record.c

/* Process record and replay target for GDB, the GNU debugger.

   Copyright (C) 2008-2013 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "gdbcmd.h"
#include "completer.h"
#include "record.h"
#include "observer.h"
#include "inferior.h"
#include "common/common-utils.h"

/* This is the debug switch for process record.  */
unsigned int record_debug = 0;

struct cmd_list_element *record_cmdlist = NULL;
struct cmd_list_element *set_record_cmdlist = NULL;
struct cmd_list_element *show_record_cmdlist = NULL;
struct cmd_list_element *info_record_cmdlist = NULL;

#define DEBUG(msg, args...)						\
  if (record_debug)							\
    fprintf_unfiltered (gdb_stdlog, "record: " msg "\n", ##args)

/* Find the record target in the target stack.  */

static struct target_ops *
find_record_target (void)
{
  struct target_ops *t;

  for (t = current_target.beneath; t != NULL; t = t->beneath)
    if (t->to_stratum == record_stratum)
      return t;

  return NULL;
}

/* Check that recording is active.  Throw an error, if it isn't.  */

static struct target_ops *
require_record_target (void)
{
  struct target_ops *t;

  t = find_record_target ();
  if (t == NULL)
    error (_("No record target is currently active.\n"
	     "Use one of the \"target record-<tab><tab>\" commands first."));

  return t;
}

/* See record.h.  */

int
record_read_memory (struct gdbarch *gdbarch,
		    CORE_ADDR memaddr, gdb_byte *myaddr,
		    ssize_t len)
{
  int ret = target_read_memory (memaddr, myaddr, len);

  if (ret != 0)
    DEBUG ("error reading memory at addr %s len = %ld.\n",
	   paddress (gdbarch, memaddr), (long) len);

  return ret;
}

/* Stop recording.  */

static void
record_stop (struct target_ops *t)
{
  DEBUG ("stop %s", t->to_shortname);

  if (t->to_stop_recording != NULL)
    t->to_stop_recording ();
}

/* Unpush the record target.  */

static void
record_unpush (struct target_ops *t)
{
  DEBUG ("unpush %s", t->to_shortname);

  unpush_target (t);
}

/* See record.h.  */

void
record_disconnect (struct target_ops *t, char *args, int from_tty)
{
  gdb_assert (t->to_stratum == record_stratum);

  DEBUG ("disconnect %s", t->to_shortname);

  record_stop (t);
  record_unpush (t);

  target_disconnect (args, from_tty);
}

/* See record.h.  */

void
record_detach (struct target_ops *t, char *args, int from_tty)
{
  gdb_assert (t->to_stratum == record_stratum);

  DEBUG ("detach %s", t->to_shortname);

  record_stop (t);
  record_unpush (t);

  target_detach (args, from_tty);
}

/* See record.h.  */

void
record_mourn_inferior (struct target_ops *t)
{
  gdb_assert (t->to_stratum == record_stratum);

  DEBUG ("mourn inferior %s", t->to_shortname);

  /* It is safer to not stop recording.  Resources will be freed when
     threads are discarded.  */
  record_unpush (t);

  target_mourn_inferior ();
}

/* See record.h.  */

void
record_kill (struct target_ops *t)
{
  gdb_assert (t->to_stratum == record_stratum);

  DEBUG ("kill %s", t->to_shortname);

  /* It is safer to not stop recording.  Resources will be freed when
     threads are discarded.  */
  record_unpush (t);

  target_kill ();
}

/* Implement "show record debug" command.  */

static void
show_record_debug (struct ui_file *file, int from_tty,
		   struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Debugging of process record target is %s.\n"),
		    value);
}

/* Alias for "target record".  */

static void
cmd_record_start (char *args, int from_tty)
{
  execute_command ("target record-full", from_tty);
}

/* Truncate the record log from the present point
   of replay until the end.  */

static void
cmd_record_delete (char *args, int from_tty)
{
  require_record_target ();

  if (!target_record_is_replaying ())
    {
      printf_unfiltered (_("Already at end of record list.\n"));
      return;
    }

  if (!target_supports_delete_record ())
    {
      printf_unfiltered (_("The current record target does not support "
			   "this operation.\n"));
      return;
    }

  if (!from_tty || query (_("Delete the log from this point forward "
			    "and begin to record the running message "
			    "at current PC?")))
    target_delete_record ();
}

/* Implement the "stoprecord" or "record stop" command.  */

static void
cmd_record_stop (char *args, int from_tty)
{
  struct target_ops *t;

  t = require_record_target ();

  record_stop (t);
  record_unpush (t);

  printf_unfiltered (_("Process record is stopped and all execution "
		       "logs are deleted.\n"));

  observer_notify_record_changed (current_inferior (), 0);
}

/* The "set record" command.  */

static void
set_record_command (char *args, int from_tty)
{
  printf_unfiltered (_("\"set record\" must be followed "
		       "by an apporpriate subcommand.\n"));
  help_list (set_record_cmdlist, "set record ", all_commands, gdb_stdout);
}

/* The "show record" command.  */

static void
show_record_command (char *args, int from_tty)
{
  cmd_show_list (show_record_cmdlist, from_tty, "");
}

/* The "info record" command.  */

static void
info_record_command (char *args, int from_tty)
{
  struct target_ops *t;

  t = find_record_target ();
  if (t == NULL)
    {
      printf_filtered (_("No record target is currently active.\n"));
      return;
    }

  printf_filtered (_("Active record target: %s\n"), t->to_shortname);
  if (t->to_info_record != NULL)
    t->to_info_record ();
}

/* The "record save" command.  */

static void
cmd_record_save (char *args, int from_tty)
{
  char *recfilename, recfilename_buffer[40];

  require_record_target ();

  if (args != NULL && *args != 0)
    recfilename = args;
  else
    {
      /* Default recfile name is "gdb_record.PID".  */
      xsnprintf (recfilename_buffer, sizeof (recfilename_buffer),
                "gdb_record.%d", PIDGET (inferior_ptid));
      recfilename = recfilename_buffer;
    }

  target_save_record (recfilename);
}

/* "record goto" command.  Argument is an instruction number,
   as given by "info record".

   Rewinds the recording (forward or backward) to the given instruction.  */

void
cmd_record_goto (char *arg, int from_tty)
{
  require_record_target ();

  if (arg == NULL || *arg == '\0')
    error (_("Command requires an argument (insn number to go to)."));

  if (strncmp (arg, "start", strlen ("start")) == 0
      || strncmp (arg, "begin", strlen ("begin")) == 0)
    target_goto_record_begin ();
  else if (strncmp (arg, "end", strlen ("end")) == 0)
    target_goto_record_end ();
  else
    {
      ULONGEST insn;

      insn = parse_and_eval_long (arg);
      target_goto_record (insn);
    }
}

/* Provide a prototype to silence -Wmissing-prototypes.  */
extern initialize_file_ftype _initialize_record;

void
_initialize_record (void)
{
  struct cmd_list_element *c;

  add_setshow_zuinteger_cmd ("record", no_class, &record_debug,
			     _("Set debugging of record/replay feature."),
			     _("Show debugging of record/replay feature."),
			     _("When enabled, debugging output for "
			       "record/replay feature is displayed."),
			     NULL, show_record_debug, &setdebuglist,
			     &showdebuglist);

  c = add_prefix_cmd ("record", class_obscure, cmd_record_start,
		      _("Start recording."),
		      &record_cmdlist, "record ", 0, &cmdlist);
  set_cmd_completer (c, filename_completer);

  add_com_alias ("rec", "record", class_obscure, 1);
  add_prefix_cmd ("record", class_support, set_record_command,
		  _("Set record options"), &set_record_cmdlist,
		  "set record ", 0, &setlist);
  add_alias_cmd ("rec", "record", class_obscure, 1, &setlist);
  add_prefix_cmd ("record", class_support, show_record_command,
		  _("Show record options"), &show_record_cmdlist,
		  "show record ", 0, &showlist);
  add_alias_cmd ("rec", "record", class_obscure, 1, &showlist);
  add_prefix_cmd ("record", class_support, info_record_command,
		  _("Info record options"), &info_record_cmdlist,
		  "info record ", 0, &infolist);
  add_alias_cmd ("rec", "record", class_obscure, 1, &infolist);

  c = add_cmd ("save", class_obscure, cmd_record_save,
	       _("Save the execution log to a file.\n\
Argument is optional filename.\n\
Default filename is 'gdb_record.<process_id>'."),
	       &record_cmdlist);
  set_cmd_completer (c, filename_completer);

  add_cmd ("delete", class_obscure, cmd_record_delete,
	   _("Delete the rest of execution log and start recording it anew."),
           &record_cmdlist);
  add_alias_cmd ("d", "delete", class_obscure, 1, &record_cmdlist);
  add_alias_cmd ("del", "delete", class_obscure, 1, &record_cmdlist);

  add_cmd ("stop", class_obscure, cmd_record_stop,
	   _("Stop the record/replay target."),
           &record_cmdlist);
  add_alias_cmd ("s", "stop", class_obscure, 1, &record_cmdlist);

  add_cmd ("goto", class_obscure, cmd_record_goto, _("\
Restore the program to its state at instruction number N.\n\
Argument is instruction number, as shown by 'info record'."),
	   &record_cmdlist);
}