gdb/inferior.c

   1 /* Multi-process control for GDB, the GNU debugger.
   2
   3    Copyright (C) 2008-2016 Free Software Foundation, Inc.
   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 "exec.h"
  22 #include "inferior.h"
  23 #include "target.h"
  24 #include "command.h"
  25 #include "completer.h"
  26 #include "gdbcmd.h"
  27 #include "gdbthread.h"
  28 #include "ui-out.h"
  29 #include "observer.h"
  30 #include "gdbcore.h"
  31 #include "symfile.h"
  32 #include "environ.h"
  33 #include "cli/cli-utils.h"
  34 #include "continuations.h"
  35 #include "arch-utils.h"
  36 #include "target-descriptions.h"
  37 #include "readline/tilde.h"
  38
  39 void _initialize_inferiors (void);
  40
  41 /* Keep a registry of per-inferior data-pointers required by other GDB
  42    modules.  */
  43
  44 DEFINE_REGISTRY (inferior, REGISTRY_ACCESS_FIELD)
  45
  46 struct inferior *inferior_list = NULL;
  47 static int highest_inferior_num;
  48
  49 /* Print notices on inferior events (attach, detach, etc.), set with
  50    `set print inferior-events'.  */
  51 static int print_inferior_events = 0;
  52
  53 /* The Current Inferior.  */
  54 static struct inferior *current_inferior_ = NULL;
  55
  56 struct inferior*
  57 current_inferior (void)
  58 {
  59   return current_inferior_;
  60 }
  61
  62 void
  63 set_current_inferior (struct inferior *inf)
  64 {
  65   /* There's always an inferior.  */
  66   gdb_assert (inf != NULL);
  67
  68   current_inferior_ = inf;
  69 }
  70
  71 /* A cleanups callback, helper for save_current_program_space
  72    below.  */
  73
  74 static void
  75 restore_inferior (void *arg)
  76 {
  77   struct inferior *saved_inferior = (struct inferior *) arg;
  78
  79   set_current_inferior (saved_inferior);
  80 }
  81
  82 /* Save the current program space so that it may be restored by a later
  83    call to do_cleanups.  Returns the struct cleanup pointer needed for
  84    later doing the cleanup.  */
  85
  86 struct cleanup *
  87 save_current_inferior (void)
  88 {
  89   struct cleanup *old_chain = make_cleanup (restore_inferior,
  90                                             current_inferior_);
  91
  92   return old_chain;
  93 }
  94
  95 static void
  96 free_inferior (struct inferior *inf)
  97 {
  98   discard_all_inferior_continuations (inf);
  99   inferior_free_data (inf);
 100   xfree (inf->args);
 101   xfree (inf->terminal);
 102   free_environ (inf->environment);
 103   target_desc_info_free (inf->tdesc_info);
 104   xfree (inf->priv);
 105   xfree (inf);
 106 }
 107
 108 void
 109 init_inferior_list (void)
 110 {
 111   struct inferior *inf, *infnext;
 112
 113   highest_inferior_num = 0;
 114   if (!inferior_list)
 115     return;
 116
 117   for (inf = inferior_list; inf; inf = infnext)
 118     {
 119       infnext = inf->next;
 120       free_inferior (inf);
 121     }
 122
 123   inferior_list = NULL;
 124 }
 125
 126 struct inferior *
 127 add_inferior_silent (int pid)
 128 {
 129   struct inferior *inf;
 130
 131   inf = XNEW (struct inferior);
 132   memset (inf, 0, sizeof (*inf));
 133   inf->pid = pid;
 134
 135   inf->control.stop_soon = NO_STOP_QUIETLY;
 136
 137   inf->num = ++highest_inferior_num;
 138
 139   if (inferior_list == NULL)
 140     inferior_list = inf;
 141   else
 142     {
 143       struct inferior *last;
 144
 145       for (last = inferior_list; last->next != NULL; last = last->next)
 146         ;
 147       last->next = inf;
 148     }
 149
 150   inf->environment = make_environ ();
 151   init_environ (inf->environment);
 152
 153   inferior_alloc_data (inf);
 154
 155   observer_notify_inferior_added (inf);
 156
 157   if (pid != 0)
 158     inferior_appeared (inf, pid);
 159
 160   return inf;
 161 }
 162
 163 struct inferior *
 164 add_inferior (int pid)
 165 {
 166   struct inferior *inf = add_inferior_silent (pid);
 167
 168   if (print_inferior_events)
 169     printf_unfiltered (_("[New inferior %d]\n"), pid);
 170
 171   return inf;
 172 }
 173
 174 struct delete_thread_of_inferior_arg
 175 {
 176   int pid;
 177   int silent;
 178 };
 179
 180 static int
 181 delete_thread_of_inferior (struct thread_info *tp, void *data)
 182 {
 183   struct delete_thread_of_inferior_arg *arg
 184     = (struct delete_thread_of_inferior_arg *) data;
 185
 186   if (ptid_get_pid (tp->ptid) == arg->pid)
 187     {
 188       if (arg->silent)
 189         delete_thread_silent (tp->ptid);
 190       else
 191         delete_thread (tp->ptid);
 192     }
 193
 194   return 0;
 195 }
 196
 197 void
 198 delete_inferior (struct inferior *todel)
 199 {
 200   struct inferior *inf, *infprev;
 201   struct delete_thread_of_inferior_arg arg;
 202
 203   infprev = NULL;
 204
 205   for (inf = inferior_list; inf; infprev = inf, inf = inf->next)
 206     if (inf == todel)
 207       break;
 208
 209   if (!inf)
 210     return;
 211
 212   arg.pid = inf->pid;
 213   arg.silent = 1;
 214
 215   iterate_over_threads (delete_thread_of_inferior, &arg);
 216
 217   if (infprev)
 218     infprev->next = inf->next;
 219   else
 220     inferior_list = inf->next;
 221
 222   observer_notify_inferior_removed (inf);
 223
 224   /* If this program space is rendered useless, remove it. */
 225   if (program_space_empty_p (inf->pspace))
 226     delete_program_space (inf->pspace);
 227
 228   free_inferior (inf);
 229 }
 230
 231 /* If SILENT then be quiet -- don't announce a inferior exit, or the
 232    exit of its threads.  */
 233
 234 static void
 235 exit_inferior_1 (struct inferior *inftoex, int silent)
 236 {
 237   struct inferior *inf;
 238   struct delete_thread_of_inferior_arg arg;
 239
 240   for (inf = inferior_list; inf; inf = inf->next)
 241     if (inf == inftoex)
 242       break;
 243
 244   if (!inf)
 245     return;
 246
 247   arg.pid = inf->pid;
 248   arg.silent = silent;
 249
 250   iterate_over_threads (delete_thread_of_inferior, &arg);
 251
 252   observer_notify_inferior_exit (inf);
 253
 254   inf->pid = 0;
 255   inf->fake_pid_p = 0;
 256   xfree (inf->priv);
 257   inf->priv = NULL;
 258
 259   if (inf->vfork_parent != NULL)
 260     {
 261       inf->vfork_parent->vfork_child = NULL;
 262       inf->vfork_parent = NULL;
 263     }
 264   if (inf->vfork_child != NULL)
 265     {
 266       inf->vfork_child->vfork_parent = NULL;
 267       inf->vfork_child = NULL;
 268     }
 269
 270   inf->pending_detach = 0;
 271 }
 272
 273 void
 274 exit_inferior (int pid)
 275 {
 276   struct inferior *inf = find_inferior_pid (pid);
 277
 278   exit_inferior_1 (inf, 0);
 279
 280   if (print_inferior_events)
 281     printf_unfiltered (_("[Inferior %d exited]\n"), pid);
 282 }
 283
 284 void
 285 exit_inferior_silent (int pid)
 286 {
 287   struct inferior *inf = find_inferior_pid (pid);
 288
 289   exit_inferior_1 (inf, 1);
 290 }
 291
 292 void
 293 exit_inferior_num_silent (int num)
 294 {
 295   struct inferior *inf = find_inferior_id (num);
 296
 297   exit_inferior_1 (inf, 1);
 298 }
 299
 300 void
 301 detach_inferior (int pid)
 302 {
 303   struct inferior *inf = find_inferior_pid (pid);
 304
 305   exit_inferior_1 (inf, 0);
 306
 307   if (print_inferior_events)
 308     printf_unfiltered (_("[Inferior %d detached]\n"), pid);
 309 }
 310
 311 void
 312 inferior_appeared (struct inferior *inf, int pid)
 313 {
 314   inf->pid = pid;
 315   inf->has_exit_code = 0;
 316   inf->exit_code = 0;
 317
 318   observer_notify_inferior_appeared (inf);
 319 }
 320
 321 void
 322 discard_all_inferiors (void)
 323 {
 324   struct inferior *inf;
 325
 326   for (inf = inferior_list; inf; inf = inf->next)
 327     {
 328       if (inf->pid != 0)
 329         exit_inferior_silent (inf->pid);
 330     }
 331 }
 332
 333 struct inferior *
 334 find_inferior_id (int num)
 335 {
 336   struct inferior *inf;
 337
 338   for (inf = inferior_list; inf; inf = inf->next)
 339     if (inf->num == num)
 340       return inf;
 341
 342   return NULL;
 343 }
 344
 345 struct inferior *
 346 find_inferior_pid (int pid)
 347 {
 348   struct inferior *inf;
 349
 350   /* Looking for inferior pid == 0 is always wrong, and indicative of
 351      a bug somewhere else.  There may be more than one with pid == 0,
 352      for instance.  */
 353   gdb_assert (pid != 0);
 354
 355   for (inf = inferior_list; inf; inf = inf->next)
 356     if (inf->pid == pid)
 357       return inf;
 358
 359   return NULL;
 360 }
 361
 362 /* See inferior.h */
 363
 364 struct inferior *
 365 find_inferior_ptid (ptid_t ptid)
 366 {
 367   return find_inferior_pid (ptid_get_pid (ptid));
 368 }
 369
 370 /* See inferior.h.  */
 371
 372 struct inferior *
 373 find_inferior_for_program_space (struct program_space *pspace)
 374 {
 375   struct inferior *inf = current_inferior ();
 376
 377   if (inf->pspace == pspace)
 378     return inf;
 379
 380   for (inf = inferior_list; inf != NULL; inf = inf->next)
 381     {
 382       if (inf->pspace == pspace)
 383         return inf;
 384     }
 385
 386   return NULL;
 387 }
 388
 389 struct inferior *
 390 iterate_over_inferiors (int (*callback) (struct inferior *, void *),
 391                         void *data)
 392 {
 393   struct inferior *inf, *infnext;
 394
 395   for (inf = inferior_list; inf; inf = infnext)
 396     {
 397       infnext = inf->next;
 398       if ((*callback) (inf, data))
 399         return inf;
 400     }
 401
 402   return NULL;
 403 }
 404
 405 int
 406 valid_gdb_inferior_id (int num)
 407 {
 408   struct inferior *inf;
 409
 410   for (inf = inferior_list; inf; inf = inf->next)
 411     if (inf->num == num)
 412       return 1;
 413
 414   return 0;
 415 }
 416
 417 int
 418 pid_to_gdb_inferior_id (int pid)
 419 {
 420   struct inferior *inf;
 421
 422   for (inf = inferior_list; inf; inf = inf->next)
 423     if (inf->pid == pid)
 424       return inf->num;
 425
 426   return 0;
 427 }
 428
 429 int
 430 gdb_inferior_id_to_pid (int num)
 431 {
 432   struct inferior *inferior = find_inferior_id (num);
 433   if (inferior)
 434     return inferior->pid;
 435   else
 436     return -1;
 437 }
 438
 439 int
 440 in_inferior_list (int pid)
 441 {
 442   struct inferior *inf;
 443
 444   for (inf = inferior_list; inf; inf = inf->next)
 445     if (inf->pid == pid)
 446       return 1;
 447
 448   return 0;
 449 }
 450
 451 int
 452 have_inferiors (void)
 453 {
 454   struct inferior *inf;
 455
 456   for (inf = inferior_list; inf; inf = inf->next)
 457     if (inf->pid != 0)
 458       return 1;
 459
 460   return 0;
 461 }
 462
 463 /* Return the number of live inferiors.  We account for the case
 464    where an inferior might have a non-zero pid but no threads, as
 465    in the middle of a 'mourn' operation.  */
 466
 467 int
 468 number_of_live_inferiors (void)
 469 {
 470   struct inferior *inf;
 471   int num_inf = 0;
 472
 473   for (inf = inferior_list; inf; inf = inf->next)
 474     if (inf->pid != 0)
 475       {
 476         struct thread_info *tp;
 477
 478         ALL_NON_EXITED_THREADS (tp)
 479          if (tp && ptid_get_pid (tp->ptid) == inf->pid)
 480            if (target_has_execution_1 (tp->ptid))
 481              {
 482                /* Found a live thread in this inferior, go to the next
 483                   inferior.  */
 484                ++num_inf;
 485                break;
 486              }
 487       }
 488
 489   return num_inf;
 490 }
 491
 492 /* Return true if there is at least one live inferior.  */
 493
 494 int
 495 have_live_inferiors (void)
 496 {
 497   return number_of_live_inferiors () > 0;
 498 }
 499
 500 /* Prune away any unused inferiors, and then prune away no longer used
 501    program spaces.  */
 502
 503 void
 504 prune_inferiors (void)
 505 {
 506   struct inferior *ss, **ss_link;
 507   struct inferior *current = current_inferior ();
 508
 509   ss = inferior_list;
 510   ss_link = &inferior_list;
 511   while (ss)
 512     {
 513       if (ss == current
 514           || !ss->removable
 515           || ss->pid != 0)
 516         {
 517           ss_link = &ss->next;
 518           ss = *ss_link;
 519           continue;
 520         }
 521
 522       *ss_link = ss->next;
 523       delete_inferior (ss);
 524       ss = *ss_link;
 525     }
 526 }
 527
 528 /* Simply returns the count of inferiors.  */
 529
 530 int
 531 number_of_inferiors (void)
 532 {
 533   struct inferior *inf;
 534   int count = 0;
 535
 536   for (inf = inferior_list; inf != NULL; inf = inf->next)
 537     count++;
 538
 539   return count;
 540 }
 541
 542 /* Converts an inferior process id to a string.  Like
 543    target_pid_to_str, but special cases the null process.  */
 544
 545 static char *
 546 inferior_pid_to_str (int pid)
 547 {
 548   if (pid != 0)
 549     return target_pid_to_str (pid_to_ptid (pid));
 550   else
 551     return _("<null>");
 552 }
 553
 554 /* See inferior.h.  */
 555
 556 void
 557 print_selected_inferior (struct ui_out *uiout)
 558 {
 559   char buf[PATH_MAX + 256];
 560   struct inferior *inf = current_inferior ();
 561
 562   xsnprintf (buf, sizeof (buf),
 563              _("[Switching to inferior %d [%s] (%s)]\n"),
 564              inf->num,
 565              inferior_pid_to_str (inf->pid),
 566              (inf->pspace->pspace_exec_filename != NULL
 567               ? inf->pspace->pspace_exec_filename
 568               : _("<noexec>")));
 569   ui_out_text (uiout, buf);
 570 }
 571
 572 /* Prints the list of inferiors and their details on UIOUT.  This is a
 573    version of 'info_inferior_command' suitable for use from MI.
 574
 575    If REQUESTED_INFERIORS is not NULL, it's a list of GDB ids of the
 576    inferiors that should be printed.  Otherwise, all inferiors are
 577    printed.  */
 578
 579 static void
 580 print_inferior (struct ui_out *uiout, char *requested_inferiors)
 581 {
 582   struct inferior *inf;
 583   struct cleanup *old_chain;
 584   int inf_count = 0;
 585
 586   /* Compute number of inferiors we will print.  */
 587   for (inf = inferior_list; inf; inf = inf->next)
 588     {
 589       if (!number_is_in_list (requested_inferiors, inf->num))
 590         continue;
 591
 592       ++inf_count;
 593     }
 594
 595   if (inf_count == 0)
 596     {
 597       ui_out_message (uiout, "No inferiors.\n");
 598       return;
 599     }
 600
 601   old_chain = make_cleanup_ui_out_table_begin_end (uiout, 4, inf_count,
 602                                                    "inferiors");
 603   ui_out_table_header (uiout, 1, ui_left, "current", "");
 604   ui_out_table_header (uiout, 4, ui_left, "number", "Num");
 605   ui_out_table_header (uiout, 17, ui_left, "target-id", "Description");
 606   ui_out_table_header (uiout, 17, ui_left, "exec", "Executable");
 607
 608   ui_out_table_body (uiout);
 609   for (inf = inferior_list; inf; inf = inf->next)
 610     {
 611       struct cleanup *chain2;
 612
 613       if (!number_is_in_list (requested_inferiors, inf->num))
 614         continue;
 615
 616       chain2 = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 617
 618       if (inf == current_inferior ())
 619         ui_out_field_string (uiout, "current", "*");
 620       else
 621         ui_out_field_skip (uiout, "current");
 622
 623       ui_out_field_int (uiout, "number", inf->num);
 624
 625       ui_out_field_string (uiout, "target-id",
 626                            inferior_pid_to_str (inf->pid));
 627
 628       if (inf->pspace->pspace_exec_filename != NULL)
 629         ui_out_field_string (uiout, "exec", inf->pspace->pspace_exec_filename);
 630       else
 631         ui_out_field_skip (uiout, "exec");
 632
 633       /* Print extra info that isn't really fit to always present in
 634          tabular form.  Currently we print the vfork parent/child
 635          relationships, if any.  */
 636       if (inf->vfork_parent)
 637         {
 638           ui_out_text (uiout, _("\n\tis vfork child of inferior "));
 639           ui_out_field_int (uiout, "vfork-parent", inf->vfork_parent->num);
 640         }
 641       if (inf->vfork_child)
 642         {
 643           ui_out_text (uiout, _("\n\tis vfork parent of inferior "));
 644           ui_out_field_int (uiout, "vfork-child", inf->vfork_child->num);
 645         }
 646
 647       ui_out_text (uiout, "\n");
 648       do_cleanups (chain2);
 649     }
 650
 651   do_cleanups (old_chain);
 652 }
 653
 654 static void
 655 detach_inferior_command (char *args, int from_tty)
 656 {
 657   struct thread_info *tp;
 658
 659   if (!args || !*args)
 660     error (_("Requires argument (inferior id(s) to detach)"));
 661
 662   number_or_range_parser parser (args);
 663   while (!parser.finished ())
 664     {
 665       int num = parser.get_number ();
 666
 667       if (!valid_gdb_inferior_id (num))
 668         {
 669           warning (_("Inferior ID %d not known."), num);
 670           continue;
 671         }
 672
 673       int pid = gdb_inferior_id_to_pid (num);
 674       if (pid == 0)
 675         {
 676           warning (_("Inferior ID %d is not running."), num);
 677           continue;
 678         }
 679
 680       tp = any_thread_of_process (pid);
 681       if (!tp)
 682         {
 683           warning (_("Inferior ID %d has no threads."), num);
 684           continue;
 685         }
 686
 687       switch_to_thread (tp->ptid);
 688
 689       detach_command (NULL, from_tty);
 690     }
 691 }
 692
 693 static void
 694 kill_inferior_command (char *args, int from_tty)
 695 {
 696   struct thread_info *tp;
 697
 698   if (!args || !*args)
 699     error (_("Requires argument (inferior id(s) to kill)"));
 700
 701   number_or_range_parser parser (args);
 702   while (!parser.finished ())
 703     {
 704       int num = parser.get_number ();
 705
 706       if (!valid_gdb_inferior_id (num))
 707         {
 708           warning (_("Inferior ID %d not known."), num);
 709           continue;
 710         }
 711
 712       int pid = gdb_inferior_id_to_pid (num);
 713       if (pid == 0)
 714         {
 715           warning (_("Inferior ID %d is not running."), num);
 716           continue;
 717         }
 718
 719       tp = any_thread_of_process (pid);
 720       if (!tp)
 721         {
 722           warning (_("Inferior ID %d has no threads."), num);
 723           continue;
 724         }
 725
 726       switch_to_thread (tp->ptid);
 727
 728       target_kill ();
 729     }
 730
 731   bfd_cache_close_all ();
 732 }
 733
 734 static void
 735 inferior_command (char *args, int from_tty)
 736 {
 737   struct inferior *inf;
 738   int num;
 739
 740   num = parse_and_eval_long (args);
 741
 742   inf = find_inferior_id (num);
 743   if (inf == NULL)
 744     error (_("Inferior ID %d not known."), num);
 745
 746   if (inf->pid != 0)
 747     {
 748       if (inf->pid != ptid_get_pid (inferior_ptid))
 749         {
 750           struct thread_info *tp;
 751
 752           tp = any_thread_of_process (inf->pid);
 753           if (!tp)
 754             error (_("Inferior has no threads."));
 755
 756           switch_to_thread (tp->ptid);
 757         }
 758
 759       observer_notify_user_selected_context_changed
 760         (USER_SELECTED_INFERIOR
 761          | USER_SELECTED_THREAD
 762          | USER_SELECTED_FRAME);
 763     }
 764   else
 765     {
 766       set_current_inferior (inf);
 767       switch_to_thread (null_ptid);
 768       set_current_program_space (inf->pspace);
 769
 770       observer_notify_user_selected_context_changed (USER_SELECTED_INFERIOR);
 771     }
 772 }
 773
 774 /* Print information about currently known inferiors.  */
 775
 776 static void
 777 info_inferiors_command (char *args, int from_tty)
 778 {
 779   print_inferior (current_uiout, args);
 780 }
 781
 782 /* remove-inferior ID */
 783
 784 static void
 785 remove_inferior_command (char *args, int from_tty)
 786 {
 787   if (args == NULL || *args == '\0')
 788     error (_("Requires an argument (inferior id(s) to remove)"));
 789
 790   number_or_range_parser parser (args);
 791   while (!parser.finished ())
 792     {
 793       int num = parser.get_number ();
 794       struct inferior *inf = find_inferior_id (num);
 795
 796       if (inf == NULL)
 797         {
 798           warning (_("Inferior ID %d not known."), num);
 799           continue;
 800         }
 801
 802       if (inf == current_inferior ())
 803         {
 804           warning (_("Can not remove current inferior %d."), num);
 805           continue;
 806         }
 807
 808       if (inf->pid != 0)
 809         {
 810           warning (_("Can not remove active inferior %d."), num);
 811           continue;
 812         }
 813
 814       delete_inferior (inf);
 815     }
 816 }
 817
 818 struct inferior *
 819 add_inferior_with_spaces (void)
 820 {
 821   struct address_space *aspace;
 822   struct program_space *pspace;
 823   struct inferior *inf;
 824   struct gdbarch_info info;
 825
 826   /* If all inferiors share an address space on this system, this
 827      doesn't really return a new address space; otherwise, it
 828      really does.  */
 829   aspace = maybe_new_address_space ();
 830   pspace = add_program_space (aspace);
 831   inf = add_inferior (0);
 832   inf->pspace = pspace;
 833   inf->aspace = pspace->aspace;
 834
 835   /* Setup the inferior's initial arch, based on information obtained
 836      from the global "set ..." options.  */
 837   gdbarch_info_init (&info);
 838   inf->gdbarch = gdbarch_find_by_info (info);
 839   /* The "set ..." options reject invalid settings, so we should
 840      always have a valid arch by now.  */
 841   gdb_assert (inf->gdbarch != NULL);
 842
 843   return inf;
 844 }
 845
 846 /* add-inferior [-copies N] [-exec FILENAME]  */
 847
 848 static void
 849 add_inferior_command (char *args, int from_tty)
 850 {
 851   int i, copies = 1;
 852   char *exec = NULL;
 853   char **argv;
 854   symfile_add_flags add_flags = 0;
 855   struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
 856
 857   if (from_tty)
 858     add_flags |= SYMFILE_VERBOSE;
 859
 860   if (args)
 861     {
 862       argv = gdb_buildargv (args);
 863       make_cleanup_freeargv (argv);
 864
 865       for (; *argv != NULL; argv++)
 866         {
 867           if (**argv == '-')
 868             {
 869               if (strcmp (*argv, "-copies") == 0)
 870                 {
 871                   ++argv;
 872                   if (!*argv)
 873                     error (_("No argument to -copies"));
 874                   copies = parse_and_eval_long (*argv);
 875                 }
 876               else if (strcmp (*argv, "-exec") == 0)
 877                 {
 878                   ++argv;
 879                   if (!*argv)
 880                     error (_("No argument to -exec"));
 881                   exec = tilde_expand (*argv);
 882                   make_cleanup (xfree, exec);
 883                 }
 884             }
 885           else
 886             error (_("Invalid argument"));
 887         }
 888     }
 889
 890   save_current_space_and_thread ();
 891
 892   for (i = 0; i < copies; ++i)
 893     {
 894       struct inferior *inf = add_inferior_with_spaces ();
 895
 896       printf_filtered (_("Added inferior %d\n"), inf->num);
 897
 898       if (exec != NULL)
 899         {
 900           /* Switch over temporarily, while reading executable and
 901              symbols.q.  */
 902           set_current_program_space (inf->pspace);
 903           set_current_inferior (inf);
 904           switch_to_thread (null_ptid);
 905
 906           exec_file_attach (exec, from_tty);
 907           symbol_file_add_main (exec, add_flags);
 908         }
 909     }
 910
 911   do_cleanups (old_chain);
 912 }
 913
 914 /* clone-inferior [-copies N] [ID] */
 915
 916 static void
 917 clone_inferior_command (char *args, int from_tty)
 918 {
 919   int i, copies = 1;
 920   char **argv;
 921   struct inferior *orginf = NULL;
 922   struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
 923
 924   if (args)
 925     {
 926       argv = gdb_buildargv (args);
 927       make_cleanup_freeargv (argv);
 928
 929       for (; *argv != NULL; argv++)
 930         {
 931           if (**argv == '-')
 932             {
 933               if (strcmp (*argv, "-copies") == 0)
 934                 {
 935                   ++argv;
 936                   if (!*argv)
 937                     error (_("No argument to -copies"));
 938                   copies = parse_and_eval_long (*argv);
 939
 940                   if (copies < 0)
 941                     error (_("Invalid copies number"));
 942                 }
 943             }
 944           else
 945             {
 946               if (orginf == NULL)
 947                 {
 948                   int num;
 949
 950                   /* The first non-option (-) argument specified the
 951                      program space ID.  */
 952                   num = parse_and_eval_long (*argv);
 953                   orginf = find_inferior_id (num);
 954
 955                   if (orginf == NULL)
 956                     error (_("Inferior ID %d not known."), num);
 957                   continue;
 958                 }
 959               else
 960                 error (_("Invalid argument"));
 961             }
 962         }
 963     }
 964
 965   /* If no inferior id was specified, then the user wants to clone the
 966      current inferior.  */
 967   if (orginf == NULL)
 968     orginf = current_inferior ();
 969
 970   save_current_space_and_thread ();
 971
 972   for (i = 0; i < copies; ++i)
 973     {
 974       struct address_space *aspace;
 975       struct program_space *pspace;
 976       struct inferior *inf;
 977
 978       /* If all inferiors share an address space on this system, this
 979          doesn't really return a new address space; otherwise, it
 980          really does.  */
 981       aspace = maybe_new_address_space ();
 982       pspace = add_program_space (aspace);
 983       inf = add_inferior (0);
 984       inf->pspace = pspace;
 985       inf->aspace = pspace->aspace;
 986       inf->gdbarch = orginf->gdbarch;
 987
 988       /* If the original inferior had a user specified target
 989          description, make the clone use it too.  */
 990       if (target_desc_info_from_user_p (inf->tdesc_info))
 991         copy_inferior_target_desc_info (inf, orginf);
 992
 993       printf_filtered (_("Added inferior %d.\n"), inf->num);
 994
 995       set_current_inferior (inf);
 996       switch_to_thread (null_ptid);
 997       clone_program_space (pspace, orginf->pspace);
 998     }
 999
1000   do_cleanups (old_chain);
1001 }
1002
1003 /* Print notices when new inferiors are created and die.  */
1004 static void
1005 show_print_inferior_events (struct ui_file *file, int from_tty,
1006                            struct cmd_list_element *c, const char *value)
1007 {
1008   fprintf_filtered (file, _("Printing of inferior events is %s.\n"), value);
1009 }
1010
1011 /* Return a new value for the selected inferior's id.  */
1012
1013 static struct value *
1014 inferior_id_make_value (struct gdbarch *gdbarch, struct internalvar *var,
1015                         void *ignore)
1016 {
1017   struct inferior *inf = current_inferior ();
1018
1019   return value_from_longest (builtin_type (gdbarch)->builtin_int, inf->num);
1020 }
1021
1022 /* Implementation of `$_inferior' variable.  */
1023
1024 static const struct internalvar_funcs inferior_funcs =
1025 {
1026   inferior_id_make_value,
1027   NULL,
1028   NULL
1029 };
1030
1031 \f
1032
1033 void
1034 initialize_inferiors (void)
1035 {
1036   struct cmd_list_element *c = NULL;
1037
1038   /* There's always one inferior.  Note that this function isn't an
1039      automatic _initialize_foo function, since other _initialize_foo
1040      routines may need to install their per-inferior data keys.  We
1041      can only allocate an inferior when all those modules have done
1042      that.  Do this after initialize_progspace, due to the
1043      current_program_space reference.  */
1044   current_inferior_ = add_inferior (0);
1045   current_inferior_->pspace = current_program_space;
1046   current_inferior_->aspace = current_program_space->aspace;
1047   /* The architecture will be initialized shortly, by
1048      initialize_current_architecture.  */
1049
1050   add_info ("inferiors", info_inferiors_command,
1051             _("IDs of specified inferiors (all inferiors if no argument)."));
1052
1053   c = add_com ("add-inferior", no_class, add_inferior_command, _("\
1054 Add a new inferior.\n\
1055 Usage: add-inferior [-copies <N>] [-exec <FILENAME>]\n\
1056 N is the optional number of inferiors to add, default is 1.\n\
1057 FILENAME is the file name of the executable to use\n\
1058 as main program."));
1059   set_cmd_completer (c, filename_completer);
1060
1061   add_com ("remove-inferiors", no_class, remove_inferior_command, _("\
1062 Remove inferior ID (or list of IDs).\n\
1063 Usage: remove-inferiors ID..."));
1064
1065   add_com ("clone-inferior", no_class, clone_inferior_command, _("\
1066 Clone inferior ID.\n\
1067 Usage: clone-inferior [-copies <N>] [ID]\n\
1068 Add N copies of inferior ID.  The new inferior has the same\n\
1069 executable loaded as the copied inferior.  If -copies is not specified,\n\
1070 adds 1 copy.  If ID is not specified, it is the current inferior\n\
1071 that is cloned."));
1072
1073   add_cmd ("inferiors", class_run, detach_inferior_command, _("\
1074 Detach from inferior ID (or list of IDS)."),
1075            &detachlist);
1076
1077   add_cmd ("inferiors", class_run, kill_inferior_command, _("\
1078 Kill inferior ID (or list of IDs)."),
1079            &killlist);
1080
1081   add_cmd ("inferior", class_run, inferior_command, _("\
1082 Use this command to switch between inferiors.\n\
1083 The new inferior ID must be currently known."),
1084            &cmdlist);
1085
1086   add_setshow_boolean_cmd ("inferior-events", no_class,
1087          &print_inferior_events, _("\
1088 Set printing of inferior events (e.g., inferior start and exit)."), _("\
1089 Show printing of inferior events (e.g., inferior start and exit)."), NULL,
1090          NULL,
1091          show_print_inferior_events,
1092          &setprintlist, &showprintlist);
1093
1094   create_internalvar_type_lazy ("_inferior", &inferior_funcs, NULL);
1095 }