gdb/remote-sim.c

   1 /* Generic remote debugging interface for simulators.
   2
   3    Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
   4    2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   5
   6    Contributed by Cygnus Support.
   7    Steve Chamberlain (sac@cygnus.com).
   8
   9    This file is part of GDB.
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 3 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  23
  24 #include "defs.h"
  25 #include "inferior.h"
  26 #include "value.h"
  27 #include "gdb_string.h"
  28 #include <ctype.h>
  29 #include <fcntl.h>
  30 #include <signal.h>
  31 #include <setjmp.h>
  32 #include <errno.h>
  33 #include "terminal.h"
  34 #include "target.h"
  35 #include "gdbcore.h"
  36 #include "gdb/callback.h"
  37 #include "gdb/remote-sim.h"
  38 #include "command.h"
  39 #include "regcache.h"
  40 #include "gdb_assert.h"
  41 #include "sim-regno.h"
  42 #include "arch-utils.h"
  43 #include "readline/readline.h"
  44 #include "gdbthread.h"
  45
  46 /* Prototypes */
  47
  48 extern void _initialize_remote_sim (void);
  49
  50 static void dump_mem (char *buf, int len);
  51
  52 static void init_callbacks (void);
  53
  54 static void end_callbacks (void);
  55
  56 static int gdb_os_write_stdout (host_callback *, const char *, int);
  57
  58 static void gdb_os_flush_stdout (host_callback *);
  59
  60 static int gdb_os_write_stderr (host_callback *, const char *, int);
  61
  62 static void gdb_os_flush_stderr (host_callback *);
  63
  64 static int gdb_os_poll_quit (host_callback *);
  65
  66 /* printf_filtered is depreciated */
  67 static void gdb_os_printf_filtered (host_callback *, const char *, ...);
  68
  69 static void gdb_os_vprintf_filtered (host_callback *, const char *, va_list);
  70
  71 static void gdb_os_evprintf_filtered (host_callback *, const char *, va_list);
  72
  73 static void gdb_os_error (host_callback *, const char *, ...);
  74
  75 static void gdbsim_fetch_register (struct regcache *regcache, int regno);
  76
  77 static void gdbsim_store_register (struct regcache *regcache, int regno);
  78
  79 static void gdbsim_kill (void);
  80
  81 static void gdbsim_load (char *prog, int fromtty);
  82
  83 static void gdbsim_open (char *args, int from_tty);
  84
  85 static void gdbsim_close (int quitting);
  86
  87 static void gdbsim_detach (char *args, int from_tty);
  88
  89 static void gdbsim_resume (ptid_t ptid, int step, enum target_signal siggnal);
  90
  91 static ptid_t gdbsim_wait (ptid_t ptid, struct target_waitstatus *status);
  92
  93 static void gdbsim_prepare_to_store (struct regcache *regcache);
  94
  95 static void gdbsim_files_info (struct target_ops *target);
  96
  97 static void gdbsim_mourn_inferior (void);
  98
  99 static void gdbsim_stop (void);
 100
 101 void simulator_command (char *args, int from_tty);
 102
 103 /* Naming convention:
 104
 105    sim_* are the interface to the simulator (see remote-sim.h).
 106    gdbsim_* are stuff which is internal to gdb.  */
 107
 108 /* Forward data declarations */
 109 extern struct target_ops gdbsim_ops;
 110
 111 static int program_loaded = 0;
 112
 113 /* We must keep track of whether the simulator has been opened or not because
 114    GDB can call a target's close routine twice, but sim_close doesn't allow
 115    this.  We also need to record the result of sim_open so we can pass it
 116    back to the other sim_foo routines.  */
 117 static SIM_DESC gdbsim_desc = 0;
 118
 119 /* This is the ptid we use while we're connected to the simulator.
 120    Its value is arbitrary, as the simulator target don't have a notion
 121    or processes or threads, but we need something non-null to place in
 122    inferior_ptid.  */
 123 static ptid_t remote_sim_ptid;
 124
 125 static void
 126 dump_mem (char *buf, int len)
 127 {
 128   if (len <= 8)
 129     {
 130       if (len == 8 || len == 4)
 131         {
 132           long l[2];
 133           memcpy (l, buf, len);
 134           printf_filtered ("\t0x%lx", l[0]);
 135           if (len == 8)
 136             printf_filtered (" 0x%lx", l[1]);
 137           printf_filtered ("\n");
 138         }
 139       else
 140         {
 141           int i;
 142           printf_filtered ("\t");
 143           for (i = 0; i < len; i++)
 144             printf_filtered ("0x%x ", buf[i]);
 145           printf_filtered ("\n");
 146         }
 147     }
 148 }
 149
 150 static host_callback gdb_callback;
 151 static int callbacks_initialized = 0;
 152
 153 /* Initialize gdb_callback.  */
 154
 155 static void
 156 init_callbacks (void)
 157 {
 158   if (!callbacks_initialized)
 159     {
 160       gdb_callback = default_callback;
 161       gdb_callback.init (&gdb_callback);
 162       gdb_callback.write_stdout = gdb_os_write_stdout;
 163       gdb_callback.flush_stdout = gdb_os_flush_stdout;
 164       gdb_callback.write_stderr = gdb_os_write_stderr;
 165       gdb_callback.flush_stderr = gdb_os_flush_stderr;
 166       gdb_callback.printf_filtered = gdb_os_printf_filtered;
 167       gdb_callback.vprintf_filtered = gdb_os_vprintf_filtered;
 168       gdb_callback.evprintf_filtered = gdb_os_evprintf_filtered;
 169       gdb_callback.error = gdb_os_error;
 170       gdb_callback.poll_quit = gdb_os_poll_quit;
 171       gdb_callback.magic = HOST_CALLBACK_MAGIC;
 172       callbacks_initialized = 1;
 173     }
 174 }
 175
 176 /* Release callbacks (free resources used by them).  */
 177
 178 static void
 179 end_callbacks (void)
 180 {
 181   if (callbacks_initialized)
 182     {
 183       gdb_callback.shutdown (&gdb_callback);
 184       callbacks_initialized = 0;
 185     }
 186 }
 187
 188 /* GDB version of os_write_stdout callback.  */
 189
 190 static int
 191 gdb_os_write_stdout (host_callback *p, const char *buf, int len)
 192 {
 193   int i;
 194   char b[2];
 195
 196   ui_file_write (gdb_stdtarg, buf, len);
 197   return len;
 198 }
 199
 200 /* GDB version of os_flush_stdout callback.  */
 201
 202 static void
 203 gdb_os_flush_stdout (host_callback *p)
 204 {
 205   gdb_flush (gdb_stdtarg);
 206 }
 207
 208 /* GDB version of os_write_stderr callback.  */
 209
 210 static int
 211 gdb_os_write_stderr (host_callback *p, const char *buf, int len)
 212 {
 213   int i;
 214   char b[2];
 215
 216   for (i = 0; i < len; i++)
 217     {
 218       b[0] = buf[i];
 219       b[1] = 0;
 220       fputs_unfiltered (b, gdb_stdtargerr);
 221     }
 222   return len;
 223 }
 224
 225 /* GDB version of os_flush_stderr callback.  */
 226
 227 static void
 228 gdb_os_flush_stderr (host_callback *p)
 229 {
 230   gdb_flush (gdb_stdtargerr);
 231 }
 232
 233 /* GDB version of printf_filtered callback.  */
 234
 235 static void
 236 gdb_os_printf_filtered (host_callback * p, const char *format,...)
 237 {
 238   va_list args;
 239   va_start (args, format);
 240
 241   vfprintf_filtered (gdb_stdout, format, args);
 242
 243   va_end (args);
 244 }
 245
 246 /* GDB version of error vprintf_filtered.  */
 247
 248 static void
 249 gdb_os_vprintf_filtered (host_callback * p, const char *format, va_list ap)
 250 {
 251   vfprintf_filtered (gdb_stdout, format, ap);
 252 }
 253
 254 /* GDB version of error evprintf_filtered.  */
 255
 256 static void
 257 gdb_os_evprintf_filtered (host_callback * p, const char *format, va_list ap)
 258 {
 259   vfprintf_filtered (gdb_stderr, format, ap);
 260 }
 261
 262 /* GDB version of error callback.  */
 263
 264 static void
 265 gdb_os_error (host_callback * p, const char *format,...)
 266 {
 267   if (deprecated_error_hook)
 268     (*deprecated_error_hook) ();
 269   else
 270     {
 271       va_list args;
 272       va_start (args, format);
 273       verror (format, args);
 274       va_end (args);
 275     }
 276 }
 277
 278 int
 279 one2one_register_sim_regno (struct gdbarch *gdbarch, int regnum)
 280 {
 281   /* Only makes sense to supply raw registers.  */
 282   gdb_assert (regnum >= 0 && regnum < gdbarch_num_regs (gdbarch));
 283   return regnum;
 284 }
 285
 286 static void
 287 gdbsim_fetch_register (struct regcache *regcache, int regno)
 288 {
 289   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 290   if (regno == -1)
 291     {
 292       for (regno = 0; regno < gdbarch_num_regs (gdbarch); regno++)
 293         gdbsim_fetch_register (regcache, regno);
 294       return;
 295     }
 296
 297   switch (gdbarch_register_sim_regno (gdbarch, regno))
 298     {
 299     case LEGACY_SIM_REGNO_IGNORE:
 300       break;
 301     case SIM_REGNO_DOES_NOT_EXIST:
 302       {
 303         /* For moment treat a `does not exist' register the same way
 304            as an ``unavailable'' register.  */
 305         char buf[MAX_REGISTER_SIZE];
 306         int nr_bytes;
 307         memset (buf, 0, MAX_REGISTER_SIZE);
 308         regcache_raw_supply (regcache, regno, buf);
 309         break;
 310       }
 311
 312     default:
 313       {
 314         static int warn_user = 1;
 315         char buf[MAX_REGISTER_SIZE];
 316         int nr_bytes;
 317         gdb_assert (regno >= 0 && regno < gdbarch_num_regs (gdbarch));
 318         memset (buf, 0, MAX_REGISTER_SIZE);
 319         nr_bytes = sim_fetch_register (gdbsim_desc,
 320                                        gdbarch_register_sim_regno
 321                                          (gdbarch, regno),
 322                                        buf,
 323                                        register_size (gdbarch, regno));
 324         if (nr_bytes > 0
 325             && nr_bytes != register_size (gdbarch, regno) && warn_user)
 326           {
 327             fprintf_unfiltered (gdb_stderr,
 328                                 "Size of register %s (%d/%d) incorrect (%d instead of %d))",
 329                                 gdbarch_register_name (gdbarch, regno),
 330                                 regno,
 331                                 gdbarch_register_sim_regno
 332                                   (gdbarch, regno),
 333                                 nr_bytes, register_size (gdbarch, regno));
 334             warn_user = 0;
 335           }
 336         /* FIXME: cagney/2002-05-27: Should check `nr_bytes == 0'
 337            indicating that GDB and the SIM have different ideas about
 338            which registers are fetchable.  */
 339         /* Else if (nr_bytes < 0): an old simulator, that doesn't
 340            think to return the register size.  Just assume all is ok.  */
 341         regcache_raw_supply (regcache, regno, buf);
 342         if (remote_debug)
 343           {
 344             printf_filtered ("gdbsim_fetch_register: %d", regno);
 345             /* FIXME: We could print something more intelligible.  */
 346             dump_mem (buf, register_size (gdbarch, regno));
 347           }
 348         break;
 349       }
 350     }
 351 }
 352
 353
 354 static void
 355 gdbsim_store_register (struct regcache *regcache, int regno)
 356 {
 357   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 358   if (regno == -1)
 359     {
 360       for (regno = 0; regno < gdbarch_num_regs (gdbarch); regno++)
 361         gdbsim_store_register (regcache, regno);
 362       return;
 363     }
 364   else if (gdbarch_register_sim_regno (gdbarch, regno) >= 0)
 365     {
 366       char tmp[MAX_REGISTER_SIZE];
 367       int nr_bytes;
 368       regcache_cooked_read (regcache, regno, tmp);
 369       nr_bytes = sim_store_register (gdbsim_desc,
 370                                      gdbarch_register_sim_regno
 371                                        (gdbarch, regno),
 372                                      tmp, register_size (gdbarch, regno));
 373       if (nr_bytes > 0 && nr_bytes != register_size (gdbarch, regno))
 374         internal_error (__FILE__, __LINE__,
 375                         _("Register size different to expected"));
 376       /* FIXME: cagney/2002-05-27: Should check `nr_bytes == 0'
 377          indicating that GDB and the SIM have different ideas about
 378          which registers are fetchable.  */
 379       if (remote_debug)
 380         {
 381           printf_filtered ("gdbsim_store_register: %d", regno);
 382           /* FIXME: We could print something more intelligible.  */
 383           dump_mem (tmp, register_size (gdbarch, regno));
 384         }
 385     }
 386 }
 387
 388 /* Kill the running program.  This may involve closing any open files
 389    and releasing other resources acquired by the simulated program.  */
 390
 391 static void
 392 gdbsim_kill (void)
 393 {
 394   if (remote_debug)
 395     printf_filtered ("gdbsim_kill\n");
 396
 397   /* There is no need to `kill' running simulator - the simulator is
 398      not running.  Mourning it is enough.  */
 399   target_mourn_inferior ();
 400 }
 401
 402 /* Load an executable file into the target process.  This is expected to
 403    not only bring new code into the target process, but also to update
 404    GDB's symbol tables to match.  */
 405
 406 static void
 407 gdbsim_load (char *args, int fromtty)
 408 {
 409   char **argv = buildargv (args);
 410   char *prog;
 411
 412   if (argv == NULL)
 413     nomem (0);
 414
 415   make_cleanup_freeargv (argv);
 416
 417   prog = tilde_expand (argv[0]);
 418
 419   if (argv[1] != NULL)
 420     error (_("GDB sim does not yet support a load offset."));
 421
 422   if (remote_debug)
 423     printf_filtered ("gdbsim_load: prog \"%s\"\n", prog);
 424
 425   /* FIXME: We will print two messages on error.
 426      Need error to either not print anything if passed NULL or need
 427      another routine that doesn't take any arguments.  */
 428   if (sim_load (gdbsim_desc, prog, NULL, fromtty) == SIM_RC_FAIL)
 429     error (_("unable to load program"));
 430
 431   /* FIXME: If a load command should reset the targets registers then
 432      a call to sim_create_inferior() should go here. */
 433
 434   program_loaded = 1;
 435 }
 436
 437
 438 /* Start an inferior process and set inferior_ptid to its pid.
 439    EXEC_FILE is the file to run.
 440    ARGS is a string containing the arguments to the program.
 441    ENV is the environment vector to pass.  Errors reported with error().
 442    On VxWorks and various standalone systems, we ignore exec_file.  */
 443 /* This is called not only when we first attach, but also when the
 444    user types "run" after having attached.  */
 445
 446 static void
 447 gdbsim_create_inferior (char *exec_file, char *args, char **env, int from_tty)
 448 {
 449   int len;
 450   char *arg_buf, **argv;
 451
 452   if (exec_file == 0 || exec_bfd == 0)
 453     warning (_("No executable file specified."));
 454   if (!program_loaded)
 455     warning (_("No program loaded."));
 456
 457   if (remote_debug)
 458     printf_filtered ("gdbsim_create_inferior: exec_file \"%s\", args \"%s\"\n",
 459                      (exec_file ? exec_file : "(NULL)"),
 460                      args);
 461
 462   if (ptid_equal (inferior_ptid, remote_sim_ptid))
 463     gdbsim_kill ();
 464   remove_breakpoints ();
 465   init_wait_for_inferior ();
 466
 467   if (exec_file != NULL)
 468     {
 469       len = strlen (exec_file) + 1 + strlen (args) + 1 + /*slop */ 10;
 470       arg_buf = (char *) alloca (len);
 471       arg_buf[0] = '\0';
 472       strcat (arg_buf, exec_file);
 473       strcat (arg_buf, " ");
 474       strcat (arg_buf, args);
 475       argv = buildargv (arg_buf);
 476       make_cleanup_freeargv (argv);
 477     }
 478   else
 479     argv = NULL;
 480   sim_create_inferior (gdbsim_desc, exec_bfd, argv, env);
 481
 482   inferior_ptid = remote_sim_ptid;
 483   add_thread_silent (inferior_ptid);
 484
 485   target_mark_running (&gdbsim_ops);
 486   insert_breakpoints ();        /* Needed to get correct instruction in cache */
 487
 488   clear_proceed_status ();
 489 }
 490
 491 /* The open routine takes the rest of the parameters from the command,
 492    and (if successful) pushes a new target onto the stack.
 493    Targets should supply this routine, if only to provide an error message.  */
 494 /* Called when selecting the simulator. EG: (gdb) target sim name.  */
 495
 496 static void
 497 gdbsim_open (char *args, int from_tty)
 498 {
 499   int len;
 500   char *arg_buf;
 501   char **argv;
 502
 503   if (remote_debug)
 504     printf_filtered ("gdbsim_open: args \"%s\"\n", args ? args : "(null)");
 505
 506   /* Remove current simulator if one exists.  Only do this if the simulator
 507      has been opened because sim_close requires it.
 508      This is important because the call to push_target below will cause
 509      sim_close to be called if the simulator is already open, but push_target
 510      is called after sim_open!  We can't move the call to push_target before
 511      the call to sim_open because sim_open may invoke `error'.  */
 512   if (gdbsim_desc != NULL)
 513     unpush_target (&gdbsim_ops);
 514
 515   len = (7 + 1                  /* gdbsim */
 516          + strlen (" -E little")
 517          + strlen (" --architecture=xxxxxxxxxx")
 518          + (args ? strlen (args) : 0)
 519          + 50) /* slack */ ;
 520   arg_buf = (char *) alloca (len);
 521   strcpy (arg_buf, "gdbsim");   /* 7 */
 522   /* Specify the byte order for the target when it is explicitly
 523      specified by the user (not auto detected). */
 524   switch (selected_byte_order ())
 525     {
 526     case BFD_ENDIAN_BIG:
 527       strcat (arg_buf, " -E big");
 528       break;
 529     case BFD_ENDIAN_LITTLE:
 530       strcat (arg_buf, " -E little");
 531       break;
 532     case BFD_ENDIAN_UNKNOWN:
 533       break;
 534     }
 535   /* Specify the architecture of the target when it has been
 536      explicitly specified */
 537   if (selected_architecture_name () != NULL)
 538     {
 539       strcat (arg_buf, " --architecture=");
 540       strcat (arg_buf, selected_architecture_name ());
 541     }
 542   /* finally, any explicit args */
 543   if (args)
 544     {
 545       strcat (arg_buf, " ");    /* 1 */
 546       strcat (arg_buf, args);
 547     }
 548   argv = buildargv (arg_buf);
 549   if (argv == NULL)
 550     error (_("Insufficient memory available to allocate simulator arg list."));
 551   make_cleanup_freeargv (argv);
 552
 553   init_callbacks ();
 554   gdbsim_desc = sim_open (SIM_OPEN_DEBUG, &gdb_callback, exec_bfd, argv);
 555
 556   if (gdbsim_desc == 0)
 557     error (_("unable to create simulator instance"));
 558
 559   push_target (&gdbsim_ops);
 560   printf_filtered ("Connected to the simulator.\n");
 561
 562   /* There's nothing running after "target sim" or "load"; not until
 563      "run".  */
 564   inferior_ptid = null_ptid;
 565   target_mark_exited (&gdbsim_ops);
 566 }
 567
 568 /* Does whatever cleanup is required for a target that we are no longer
 569    going to be calling.  Argument says whether we are quitting gdb and
 570    should not get hung in case of errors, or whether we want a clean
 571    termination even if it takes a while.  This routine is automatically
 572    always called just before a routine is popped off the target stack.
 573    Closing file descriptors and freeing memory are typical things it should
 574    do.  */
 575 /* Close out all files and local state before this target loses control. */
 576
 577 static void
 578 gdbsim_close (int quitting)
 579 {
 580   if (remote_debug)
 581     printf_filtered ("gdbsim_close: quitting %d\n", quitting);
 582
 583   program_loaded = 0;
 584
 585   if (gdbsim_desc != NULL)
 586     {
 587       sim_close (gdbsim_desc, quitting);
 588       gdbsim_desc = NULL;
 589     }
 590
 591   end_callbacks ();
 592   generic_mourn_inferior ();
 593   delete_thread_silent (remote_sim_ptid);
 594 }
 595
 596 /* Takes a program previously attached to and detaches it.
 597    The program may resume execution (some targets do, some don't) and will
 598    no longer stop on signals, etc.  We better not have left any breakpoints
 599    in the program or it'll die when it hits one.  ARGS is arguments
 600    typed by the user (e.g. a signal to send the process).  FROM_TTY
 601    says whether to be verbose or not.  */
 602 /* Terminate the open connection to the remote debugger.
 603    Use this when you want to detach and do something else with your gdb.  */
 604
 605 static void
 606 gdbsim_detach (char *args, int from_tty)
 607 {
 608   if (remote_debug)
 609     printf_filtered ("gdbsim_detach: args \"%s\"\n", args);
 610
 611   pop_target ();                /* calls gdbsim_close to do the real work */
 612   if (from_tty)
 613     printf_filtered ("Ending simulator %s debugging\n", target_shortname);
 614 }
 615
 616 /* Resume execution of the target process.  STEP says whether to single-step
 617    or to run free; SIGGNAL is the signal value (e.g. SIGINT) to be given
 618    to the target, or zero for no signal.  */
 619
 620 static enum target_signal resume_siggnal;
 621 static int resume_step;
 622
 623 static void
 624 gdbsim_resume (ptid_t ptid, int step, enum target_signal siggnal)
 625 {
 626   if (!ptid_equal (inferior_ptid, remote_sim_ptid))
 627     error (_("The program is not being run."));
 628
 629   if (remote_debug)
 630     printf_filtered ("gdbsim_resume: step %d, signal %d\n", step, siggnal);
 631
 632   resume_siggnal = siggnal;
 633   resume_step = step;
 634 }
 635
 636 /* Notify the simulator of an asynchronous request to stop.
 637
 638    The simulator shall ensure that the stop request is eventually
 639    delivered to the simulator.  If the call is made while the
 640    simulator is not running then the stop request is processed when
 641    the simulator is next resumed.
 642
 643    For simulators that do not support this operation, just abort */
 644
 645 static void
 646 gdbsim_stop (void)
 647 {
 648   if (!sim_stop (gdbsim_desc))
 649     {
 650       quit ();
 651     }
 652 }
 653
 654 /* GDB version of os_poll_quit callback.
 655    Taken from gdb/util.c - should be in a library.  */
 656
 657 static int
 658 gdb_os_poll_quit (host_callback *p)
 659 {
 660   if (deprecated_ui_loop_hook != NULL)
 661     deprecated_ui_loop_hook (0);
 662
 663   if (quit_flag)                /* gdb's idea of quit */
 664     {
 665       quit_flag = 0;            /* we've stolen it */
 666       return 1;
 667     }
 668   else if (immediate_quit)
 669     {
 670       return 1;
 671     }
 672   return 0;
 673 }
 674
 675 /* Wait for inferior process to do something.  Return pid of child,
 676    or -1 in case of error; store status through argument pointer STATUS,
 677    just as `wait' would. */
 678
 679 static void
 680 gdbsim_cntrl_c (int signo)
 681 {
 682   gdbsim_stop ();
 683 }
 684
 685 static ptid_t
 686 gdbsim_wait (ptid_t ptid, struct target_waitstatus *status)
 687 {
 688   static RETSIGTYPE (*prev_sigint) ();
 689   int sigrc = 0;
 690   enum sim_stop reason = sim_running;
 691
 692   if (remote_debug)
 693     printf_filtered ("gdbsim_wait\n");
 694
 695 #if defined (HAVE_SIGACTION) && defined (SA_RESTART)
 696   {
 697     struct sigaction sa, osa;
 698     sa.sa_handler = gdbsim_cntrl_c;
 699     sigemptyset (&sa.sa_mask);
 700     sa.sa_flags = 0;
 701     sigaction (SIGINT, &sa, &osa);
 702     prev_sigint = osa.sa_handler;
 703   }
 704 #else
 705   prev_sigint = signal (SIGINT, gdbsim_cntrl_c);
 706 #endif
 707   sim_resume (gdbsim_desc, resume_step, resume_siggnal);
 708   signal (SIGINT, prev_sigint);
 709   resume_step = 0;
 710
 711   sim_stop_reason (gdbsim_desc, &reason, &sigrc);
 712
 713   switch (reason)
 714     {
 715     case sim_exited:
 716       status->kind = TARGET_WAITKIND_EXITED;
 717       status->value.integer = sigrc;
 718       break;
 719     case sim_stopped:
 720       switch (sigrc)
 721         {
 722         case TARGET_SIGNAL_ABRT:
 723           quit ();
 724           break;
 725         case TARGET_SIGNAL_INT:
 726         case TARGET_SIGNAL_TRAP:
 727         default:
 728           status->kind = TARGET_WAITKIND_STOPPED;
 729           status->value.sig = sigrc;
 730           break;
 731         }
 732       break;
 733     case sim_signalled:
 734       status->kind = TARGET_WAITKIND_SIGNALLED;
 735       status->value.sig = sigrc;
 736       break;
 737     case sim_running:
 738     case sim_polling:
 739       /* FIXME: Is this correct? */
 740       break;
 741     }
 742
 743   return inferior_ptid;
 744 }
 745
 746 /* Get ready to modify the registers array.  On machines which store
 747    individual registers, this doesn't need to do anything.  On machines
 748    which store all the registers in one fell swoop, this makes sure
 749    that registers contains all the registers from the program being
 750    debugged.  */
 751
 752 static void
 753 gdbsim_prepare_to_store (struct regcache *regcache)
 754 {
 755   /* Do nothing, since we can store individual regs */
 756 }
 757
 758 /* Transfer LEN bytes between GDB address MYADDR and target address
 759    MEMADDR.  If WRITE is non-zero, transfer them to the target,
 760    otherwise transfer them from the target.  TARGET is unused.
 761
 762    Returns the number of bytes transferred. */
 763
 764 static int
 765 gdbsim_xfer_inferior_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len,
 766                              int write, struct mem_attrib *attrib,
 767                              struct target_ops *target)
 768 {
 769   /* If no program is running yet, then ignore the simulator for
 770      memory.  Pass the request down to the next target, hopefully
 771      an exec file.  */
 772   if (!target_has_execution)
 773     return 0;
 774
 775   if (!program_loaded)
 776     error (_("No program loaded."));
 777
 778   if (remote_debug)
 779     {
 780       /* FIXME: Send to something other than STDOUT? */
 781       printf_filtered ("gdbsim_xfer_inferior_memory: myaddr 0x");
 782       gdb_print_host_address (myaddr, gdb_stdout);
 783       printf_filtered (", memaddr 0x%s, len %d, write %d\n",
 784                        paddr_nz (memaddr), len, write);
 785       if (remote_debug && write)
 786         dump_mem (myaddr, len);
 787     }
 788
 789   if (write)
 790     {
 791       len = sim_write (gdbsim_desc, memaddr, myaddr, len);
 792     }
 793   else
 794     {
 795       len = sim_read (gdbsim_desc, memaddr, myaddr, len);
 796       if (remote_debug && len > 0)
 797         dump_mem (myaddr, len);
 798     }
 799   return len;
 800 }
 801
 802 static void
 803 gdbsim_files_info (struct target_ops *target)
 804 {
 805   char *file = "nothing";
 806
 807   if (exec_bfd)
 808     file = bfd_get_filename (exec_bfd);
 809
 810   if (remote_debug)
 811     printf_filtered ("gdbsim_files_info: file \"%s\"\n", file);
 812
 813   if (exec_bfd)
 814     {
 815       printf_filtered ("\tAttached to %s running program %s\n",
 816                        target_shortname, file);
 817       sim_info (gdbsim_desc, 0);
 818     }
 819 }
 820
 821 /* Clear the simulator's notion of what the break points are.  */
 822
 823 static void
 824 gdbsim_mourn_inferior (void)
 825 {
 826   if (remote_debug)
 827     printf_filtered ("gdbsim_mourn_inferior:\n");
 828
 829   remove_breakpoints ();
 830   target_mark_exited (&gdbsim_ops);
 831   generic_mourn_inferior ();
 832   delete_thread_silent (remote_sim_ptid);
 833 }
 834
 835 /* Pass the command argument through to the simulator verbatim.  The
 836    simulator must do any command interpretation work.  */
 837
 838 void
 839 simulator_command (char *args, int from_tty)
 840 {
 841   if (gdbsim_desc == NULL)
 842     {
 843
 844       /* PREVIOUSLY: The user may give a command before the simulator
 845          is opened. [...] (??? assuming of course one wishes to
 846          continue to allow commands to be sent to unopened simulators,
 847          which isn't entirely unreasonable). */
 848
 849       /* The simulator is a builtin abstraction of a remote target.
 850          Consistent with that model, access to the simulator, via sim
 851          commands, is restricted to the period when the channel to the
 852          simulator is open. */
 853
 854       error (_("Not connected to the simulator target"));
 855     }
 856
 857   sim_do_command (gdbsim_desc, args);
 858
 859   /* Invalidate the register cache, in case the simulator command does
 860      something funny. */
 861   registers_changed ();
 862 }
 863
 864 /* Check to see if a thread is still alive.  */
 865
 866 static int
 867 gdbsim_thread_alive (ptid_t ptid)
 868 {
 869   if (ptid_equal (ptid, remote_sim_ptid))
 870     /* The simulators' task is always alive.  */
 871     return 1;
 872
 873   return 0;
 874 }
 875
 876 /* Convert a thread ID to a string.  Returns the string in a static
 877    buffer.  */
 878
 879 static char *
 880 gdbsim_pid_to_str (ptid_t ptid)
 881 {
 882   static char buf[64];
 883
 884   if (ptid_equal (remote_sim_ptid, ptid))
 885     {
 886       xsnprintf (buf, sizeof buf, "Thread <main>");
 887       return buf;
 888     }
 889
 890   return normal_pid_to_str (ptid);
 891 }
 892
 893 /* Define the target subroutine names */
 894
 895 struct target_ops gdbsim_ops;
 896
 897 static void
 898 init_gdbsim_ops (void)
 899 {
 900   gdbsim_ops.to_shortname = "sim";
 901   gdbsim_ops.to_longname = "simulator";
 902   gdbsim_ops.to_doc = "Use the compiled-in simulator.";
 903   gdbsim_ops.to_open = gdbsim_open;
 904   gdbsim_ops.to_close = gdbsim_close;
 905   gdbsim_ops.to_detach = gdbsim_detach;
 906   gdbsim_ops.to_resume = gdbsim_resume;
 907   gdbsim_ops.to_wait = gdbsim_wait;
 908   gdbsim_ops.to_fetch_registers = gdbsim_fetch_register;
 909   gdbsim_ops.to_store_registers = gdbsim_store_register;
 910   gdbsim_ops.to_prepare_to_store = gdbsim_prepare_to_store;
 911   gdbsim_ops.deprecated_xfer_memory = gdbsim_xfer_inferior_memory;
 912   gdbsim_ops.to_files_info = gdbsim_files_info;
 913   gdbsim_ops.to_insert_breakpoint = memory_insert_breakpoint;
 914   gdbsim_ops.to_remove_breakpoint = memory_remove_breakpoint;
 915   gdbsim_ops.to_kill = gdbsim_kill;
 916   gdbsim_ops.to_load = gdbsim_load;
 917   gdbsim_ops.to_create_inferior = gdbsim_create_inferior;
 918   gdbsim_ops.to_mourn_inferior = gdbsim_mourn_inferior;
 919   gdbsim_ops.to_stop = gdbsim_stop;
 920   gdbsim_ops.to_thread_alive = gdbsim_thread_alive;
 921   gdbsim_ops.to_pid_to_str = gdbsim_pid_to_str;
 922   gdbsim_ops.to_stratum = process_stratum;
 923   gdbsim_ops.to_has_all_memory = 1;
 924   gdbsim_ops.to_has_memory = 1;
 925   gdbsim_ops.to_has_stack = 1;
 926   gdbsim_ops.to_has_registers = 1;
 927   gdbsim_ops.to_has_execution = 1;
 928   gdbsim_ops.to_magic = OPS_MAGIC;
 929
 930 #ifdef TARGET_REDEFINE_DEFAULT_OPS
 931   TARGET_REDEFINE_DEFAULT_OPS (&gdbsim_ops);
 932 #endif
 933 }
 934
 935 void
 936 _initialize_remote_sim (void)
 937 {
 938   init_gdbsim_ops ();
 939   add_target (&gdbsim_ops);
 940
 941   add_com ("sim", class_obscure, simulator_command,
 942            _("Send a command to the simulator."));
 943
 944   /* Yes, 42000 is arbitrary.  The only sense out of it, is that it
 945      isn't 0.  */
 946   remote_sim_ptid = ptid_build (42000, 0, 42000);
 947 }