gdb/inferior.c

   1 /* Multi-process control for GDB, the GNU debugger.
   2
   3    Copyright (C) 2008-2017 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 #include "progspace-and-thread.h"
  39
  40 /* Keep a registry of per-inferior data-pointers required by other GDB
  41    modules.  */
  42
  43 DEFINE_REGISTRY (inferior, REGISTRY_ACCESS_FIELD)
  44
  45 struct inferior *inferior_list = NULL;
  46 static int highest_inferior_num;
  47
  48 /* Print notices on inferior events (attach, detach, etc.), set with
  49    `set print inferior-events'.  */
  50 static int print_inferior_events = 0;
  51
  52 /* The Current Inferior.  This is a strong reference.  I.e., whenever
  53    an inferior is the current inferior, its refcount is
  54    incremented.  */
  55 static struct inferior *current_inferior_ = NULL;
  56
  57 struct inferior*
  58 current_inferior (void)
  59 {
  60   return current_inferior_;
  61 }
  62
  63 void
  64 set_current_inferior (struct inferior *inf)
  65 {
  66   /* There's always an inferior.  */
  67   gdb_assert (inf != NULL);
  68
  69   inf->incref ();
  70   current_inferior_->decref ();
  71   current_inferior_ = inf;
  72 }
  73
  74 private_inferior::~private_inferior () = default;
  75
  76 inferior::~inferior ()
  77 {
  78   inferior *inf = this;
  79
  80   discard_all_inferior_continuations (inf);
  81   inferior_free_data (inf);
  82   xfree (inf->args);
  83   xfree (inf->terminal);
  84   target_desc_info_free (inf->tdesc_info);
  85 }
  86
  87 inferior::inferior (int pid_)
  88   : num (++highest_inferior_num),
  89     pid (pid_),
  90     environment (gdb_environ::from_host_environ ()),
  91     registry_data ()
  92 {
  93   inferior_alloc_data (this);
  94 }
  95
  96 struct inferior *
  97 add_inferior_silent (int pid)
  98 {
  99   inferior *inf = new inferior (pid);
 100
 101   if (inferior_list == NULL)
 102     inferior_list = inf;
 103   else
 104     {
 105       inferior *last;
 106
 107       for (last = inferior_list; last->next != NULL; last = last->next)
 108         ;
 109       last->next = inf;
 110     }
 111
 112   observer_notify_inferior_added (inf);
 113
 114   if (pid != 0)
 115     inferior_appeared (inf, pid);
 116
 117   return inf;
 118 }
 119
 120 struct inferior *
 121 add_inferior (int pid)
 122 {
 123   struct inferior *inf = add_inferior_silent (pid);
 124
 125   if (print_inferior_events)
 126     printf_unfiltered (_("[New inferior %d]\n"), pid);
 127
 128   return inf;
 129 }
 130
 131 struct delete_thread_of_inferior_arg
 132 {
 133   int pid;
 134   int silent;
 135 };
 136
 137 static int
 138 delete_thread_of_inferior (struct thread_info *tp, void *data)
 139 {
 140   struct delete_thread_of_inferior_arg *arg
 141     = (struct delete_thread_of_inferior_arg *) data;
 142
 143   if (ptid_get_pid (tp->ptid) == arg->pid)
 144     {
 145       if (arg->silent)
 146         delete_thread_silent (tp->ptid);
 147       else
 148         delete_thread (tp->ptid);
 149     }
 150
 151   return 0;
 152 }
 153
 154 void
 155 delete_inferior (struct inferior *todel)
 156 {
 157   struct inferior *inf, *infprev;
 158   struct delete_thread_of_inferior_arg arg;
 159
 160   infprev = NULL;
 161
 162   for (inf = inferior_list; inf; infprev = inf, inf = inf->next)
 163     if (inf == todel)
 164       break;
 165
 166   if (!inf)
 167     return;
 168
 169   arg.pid = inf->pid;
 170   arg.silent = 1;
 171
 172   iterate_over_threads (delete_thread_of_inferior, &arg);
 173
 174   if (infprev)
 175     infprev->next = inf->next;
 176   else
 177     inferior_list = inf->next;
 178
 179   observer_notify_inferior_removed (inf);
 180
 181   /* If this program space is rendered useless, remove it. */
 182   if (program_space_empty_p (inf->pspace))
 183     delete_program_space (inf->pspace);
 184
 185   delete inf;
 186 }
 187
 188 /* If SILENT then be quiet -- don't announce a inferior exit, or the
 189    exit of its threads.  */
 190
 191 static void
 192 exit_inferior_1 (struct inferior *inftoex, int silent)
 193 {
 194   struct inferior *inf;
 195   struct delete_thread_of_inferior_arg arg;
 196
 197   for (inf = inferior_list; inf; inf = inf->next)
 198     if (inf == inftoex)
 199       break;
 200
 201   if (!inf)
 202     return;
 203
 204   arg.pid = inf->pid;
 205   arg.silent = silent;
 206
 207   iterate_over_threads (delete_thread_of_inferior, &arg);
 208
 209   observer_notify_inferior_exit (inf);
 210
 211   inf->pid = 0;
 212   inf->fake_pid_p = 0;
 213   inf->priv = NULL;
 214
 215   if (inf->vfork_parent != NULL)
 216     {
 217       inf->vfork_parent->vfork_child = NULL;
 218       inf->vfork_parent = NULL;
 219     }
 220   if (inf->vfork_child != NULL)
 221     {
 222       inf->vfork_child->vfork_parent = NULL;
 223       inf->vfork_child = NULL;
 224     }
 225
 226   inf->pending_detach = 0;
 227 }
 228
 229 void
 230 exit_inferior (int pid)
 231 {
 232   struct inferior *inf = find_inferior_pid (pid);
 233
 234   exit_inferior_1 (inf, 0);
 235
 236   if (print_inferior_events)
 237     printf_unfiltered (_("[Inferior %d exited]\n"), pid);
 238 }
 239
 240 void
 241 exit_inferior_silent (int pid)
 242 {
 243   struct inferior *inf = find_inferior_pid (pid);
 244
 245   exit_inferior_1 (inf, 1);
 246 }
 247
 248 void
 249 exit_inferior_num_silent (int num)
 250 {
 251   struct inferior *inf = find_inferior_id (num);
 252
 253   exit_inferior_1 (inf, 1);
 254 }
 255
 256 void
 257 detach_inferior (int pid)
 258 {
 259   struct inferior *inf = find_inferior_pid (pid);
 260
 261   exit_inferior_1 (inf, 0);
 262
 263   if (print_inferior_events)
 264     printf_unfiltered (_("[Inferior %d detached]\n"), pid);
 265 }
 266
 267 void
 268 inferior_appeared (struct inferior *inf, int pid)
 269 {
 270   inf->pid = pid;
 271   inf->has_exit_code = 0;
 272   inf->exit_code = 0;
 273
 274   observer_notify_inferior_appeared (inf);
 275 }
 276
 277 void
 278 discard_all_inferiors (void)
 279 {
 280   struct inferior *inf;
 281
 282   for (inf = inferior_list; inf; inf = inf->next)
 283     {
 284       if (inf->pid != 0)
 285         exit_inferior_silent (inf->pid);
 286     }
 287 }
 288
 289 struct inferior *
 290 find_inferior_id (int num)
 291 {
 292   struct inferior *inf;
 293
 294   for (inf = inferior_list; inf; inf = inf->next)
 295     if (inf->num == num)
 296       return inf;
 297
 298   return NULL;
 299 }
 300
 301 struct inferior *
 302 find_inferior_pid (int pid)
 303 {
 304   struct inferior *inf;
 305
 306   /* Looking for inferior pid == 0 is always wrong, and indicative of
 307      a bug somewhere else.  There may be more than one with pid == 0,
 308      for instance.  */
 309   gdb_assert (pid != 0);
 310
 311   for (inf = inferior_list; inf; inf = inf->next)
 312     if (inf->pid == pid)
 313       return inf;
 314
 315   return NULL;
 316 }
 317
 318 /* See inferior.h */
 319
 320 struct inferior *
 321 find_inferior_ptid (ptid_t ptid)
 322 {
 323   return find_inferior_pid (ptid_get_pid (ptid));
 324 }
 325
 326 /* See inferior.h.  */
 327
 328 struct inferior *
 329 find_inferior_for_program_space (struct program_space *pspace)
 330 {
 331   struct inferior *inf = current_inferior ();
 332
 333   if (inf->pspace == pspace)
 334     return inf;
 335
 336   for (inf = inferior_list; inf != NULL; inf = inf->next)
 337     {
 338       if (inf->pspace == pspace)
 339         return inf;
 340     }
 341
 342   return NULL;
 343 }
 344
 345 struct inferior *
 346 iterate_over_inferiors (int (*callback) (struct inferior *, void *),
 347                         void *data)
 348 {
 349   struct inferior *inf, *infnext;
 350
 351   for (inf = inferior_list; inf; inf = infnext)
 352     {
 353       infnext = inf->next;
 354       if ((*callback) (inf, data))
 355         return inf;
 356     }
 357
 358   return NULL;
 359 }
 360
 361 int
 362 valid_gdb_inferior_id (int num)
 363 {
 364   struct inferior *inf;
 365
 366   for (inf = inferior_list; inf; inf = inf->next)
 367     if (inf->num == num)
 368       return 1;
 369
 370   return 0;
 371 }
 372
 373 int
 374 pid_to_gdb_inferior_id (int pid)
 375 {
 376   struct inferior *inf;
 377
 378   for (inf = inferior_list; inf; inf = inf->next)
 379     if (inf->pid == pid)
 380       return inf->num;
 381
 382   return 0;
 383 }
 384
 385 int
 386 gdb_inferior_id_to_pid (int num)
 387 {
 388   struct inferior *inferior = find_inferior_id (num);
 389   if (inferior)
 390     return inferior->pid;
 391   else
 392     return -1;
 393 }
 394
 395 int
 396 in_inferior_list (int pid)
 397 {
 398   struct inferior *inf;
 399
 400   for (inf = inferior_list; inf; inf = inf->next)
 401     if (inf->pid == pid)
 402       return 1;
 403
 404   return 0;
 405 }
 406
 407 int
 408 have_inferiors (void)
 409 {
 410   struct inferior *inf;
 411
 412   for (inf = inferior_list; inf; inf = inf->next)
 413     if (inf->pid != 0)
 414       return 1;
 415
 416   return 0;
 417 }
 418
 419 /* Return the number of live inferiors.  We account for the case
 420    where an inferior might have a non-zero pid but no threads, as
 421    in the middle of a 'mourn' operation.  */
 422
 423 int
 424 number_of_live_inferiors (void)
 425 {
 426   struct inferior *inf;
 427   int num_inf = 0;
 428
 429   for (inf = inferior_list; inf; inf = inf->next)
 430     if (inf->pid != 0)
 431       {
 432         struct thread_info *tp;
 433
 434         ALL_NON_EXITED_THREADS (tp)
 435          if (tp && ptid_get_pid (tp->ptid) == inf->pid)
 436            if (target_has_execution_1 (tp->ptid))
 437              {
 438                /* Found a live thread in this inferior, go to the next
 439                   inferior.  */
 440                ++num_inf;
 441                break;
 442              }
 443       }
 444
 445   return num_inf;
 446 }
 447
 448 /* Return true if there is at least one live inferior.  */
 449
 450 int
 451 have_live_inferiors (void)
 452 {
 453   return number_of_live_inferiors () > 0;
 454 }
 455
 456 /* Prune away any unused inferiors, and then prune away no longer used
 457    program spaces.  */
 458
 459 void
 460 prune_inferiors (void)
 461 {
 462   struct inferior *ss, **ss_link;
 463
 464   ss = inferior_list;
 465   ss_link = &inferior_list;
 466   while (ss)
 467     {
 468       if (!ss->deletable ()
 469           || !ss->removable
 470           || ss->pid != 0)
 471         {
 472           ss_link = &ss->next;
 473           ss = *ss_link;
 474           continue;
 475         }
 476
 477       *ss_link = ss->next;
 478       delete_inferior (ss);
 479       ss = *ss_link;
 480     }
 481 }
 482
 483 /* Simply returns the count of inferiors.  */
 484
 485 int
 486 number_of_inferiors (void)
 487 {
 488   struct inferior *inf;
 489   int count = 0;
 490
 491   for (inf = inferior_list; inf != NULL; inf = inf->next)
 492     count++;
 493
 494   return count;
 495 }
 496
 497 /* Converts an inferior process id to a string.  Like
 498    target_pid_to_str, but special cases the null process.  */
 499
 500 static const char *
 501 inferior_pid_to_str (int pid)
 502 {
 503   if (pid != 0)
 504     return target_pid_to_str (pid_to_ptid (pid));
 505   else
 506     return _("<null>");
 507 }
 508
 509 /* See inferior.h.  */
 510
 511 void
 512 print_selected_inferior (struct ui_out *uiout)
 513 {
 514   struct inferior *inf = current_inferior ();
 515   const char *filename = inf->pspace->pspace_exec_filename;
 516
 517   if (filename == NULL)
 518     filename = _("<noexec>");
 519
 520   uiout->message (_("[Switching to inferior %d [%s] (%s)]\n"),
 521                   inf->num, inferior_pid_to_str (inf->pid), filename);
 522 }
 523
 524 /* Prints the list of inferiors and their details on UIOUT.  This is a
 525    version of 'info_inferior_command' suitable for use from MI.
 526
 527    If REQUESTED_INFERIORS is not NULL, it's a list of GDB ids of the
 528    inferiors that should be printed.  Otherwise, all inferiors are
 529    printed.  */
 530
 531 static void
 532 print_inferior (struct ui_out *uiout, const char *requested_inferiors)
 533 {
 534   struct inferior *inf;
 535   int inf_count = 0;
 536
 537   /* Compute number of inferiors we will print.  */
 538   for (inf = inferior_list; inf; inf = inf->next)
 539     {
 540       if (!number_is_in_list (requested_inferiors, inf->num))
 541         continue;
 542
 543       ++inf_count;
 544     }
 545
 546   if (inf_count == 0)
 547     {
 548       uiout->message ("No inferiors.\n");
 549       return;
 550     }
 551
 552   ui_out_emit_table table_emitter (uiout, 4, inf_count, "inferiors");
 553   uiout->table_header (1, ui_left, "current", "");
 554   uiout->table_header (4, ui_left, "number", "Num");
 555   uiout->table_header (17, ui_left, "target-id", "Description");
 556   uiout->table_header (17, ui_left, "exec", "Executable");
 557
 558   uiout->table_body ();
 559   for (inf = inferior_list; inf; inf = inf->next)
 560     {
 561       if (!number_is_in_list (requested_inferiors, inf->num))
 562         continue;
 563
 564       ui_out_emit_tuple tuple_emitter (uiout, NULL);
 565
 566       if (inf == current_inferior ())
 567         uiout->field_string ("current", "*");
 568       else
 569         uiout->field_skip ("current");
 570
 571       uiout->field_int ("number", inf->num);
 572
 573       uiout->field_string ("target-id", inferior_pid_to_str (inf->pid));
 574
 575       if (inf->pspace->pspace_exec_filename != NULL)
 576         uiout->field_string ("exec", inf->pspace->pspace_exec_filename);
 577       else
 578         uiout->field_skip ("exec");
 579
 580       /* Print extra info that isn't really fit to always present in
 581          tabular form.  Currently we print the vfork parent/child
 582          relationships, if any.  */
 583       if (inf->vfork_parent)
 584         {
 585           uiout->text (_("\n\tis vfork child of inferior "));
 586           uiout->field_int ("vfork-parent", inf->vfork_parent->num);
 587         }
 588       if (inf->vfork_child)
 589         {
 590           uiout->text (_("\n\tis vfork parent of inferior "));
 591           uiout->field_int ("vfork-child", inf->vfork_child->num);
 592         }
 593
 594       uiout->text ("\n");
 595     }
 596 }
 597
 598 static void
 599 detach_inferior_command (const char *args, int from_tty)
 600 {
 601   struct thread_info *tp;
 602
 603   if (!args || !*args)
 604     error (_("Requires argument (inferior id(s) to detach)"));
 605
 606   number_or_range_parser parser (args);
 607   while (!parser.finished ())
 608     {
 609       int num = parser.get_number ();
 610
 611       if (!valid_gdb_inferior_id (num))
 612         {
 613           warning (_("Inferior ID %d not known."), num);
 614           continue;
 615         }
 616
 617       int pid = gdb_inferior_id_to_pid (num);
 618       if (pid == 0)
 619         {
 620           warning (_("Inferior ID %d is not running."), num);
 621           continue;
 622         }
 623
 624       tp = any_thread_of_process (pid);
 625       if (!tp)
 626         {
 627           warning (_("Inferior ID %d has no threads."), num);
 628           continue;
 629         }
 630
 631       switch_to_thread (tp->ptid);
 632
 633       detach_command (NULL, from_tty);
 634     }
 635 }
 636
 637 static void
 638 kill_inferior_command (const char *args, int from_tty)
 639 {
 640   struct thread_info *tp;
 641
 642   if (!args || !*args)
 643     error (_("Requires argument (inferior id(s) to kill)"));
 644
 645   number_or_range_parser parser (args);
 646   while (!parser.finished ())
 647     {
 648       int num = parser.get_number ();
 649
 650       if (!valid_gdb_inferior_id (num))
 651         {
 652           warning (_("Inferior ID %d not known."), num);
 653           continue;
 654         }
 655
 656       int pid = gdb_inferior_id_to_pid (num);
 657       if (pid == 0)
 658         {
 659           warning (_("Inferior ID %d is not running."), num);
 660           continue;
 661         }
 662
 663       tp = any_thread_of_process (pid);
 664       if (!tp)
 665         {
 666           warning (_("Inferior ID %d has no threads."), num);
 667           continue;
 668         }
 669
 670       switch_to_thread (tp->ptid);
 671
 672       target_kill ();
 673     }
 674
 675   bfd_cache_close_all ();
 676 }
 677
 678 static void
 679 inferior_command (const char *args, int from_tty)
 680 {
 681   struct inferior *inf;
 682   int num;
 683
 684   num = parse_and_eval_long (args);
 685
 686   inf = find_inferior_id (num);
 687   if (inf == NULL)
 688     error (_("Inferior ID %d not known."), num);
 689
 690   if (inf->pid != 0)
 691     {
 692       if (inf->pid != ptid_get_pid (inferior_ptid))
 693         {
 694           struct thread_info *tp;
 695
 696           tp = any_thread_of_process (inf->pid);
 697           if (!tp)
 698             error (_("Inferior has no threads."));
 699
 700           switch_to_thread (tp->ptid);
 701         }
 702
 703       observer_notify_user_selected_context_changed
 704         (USER_SELECTED_INFERIOR
 705          | USER_SELECTED_THREAD
 706          | USER_SELECTED_FRAME);
 707     }
 708   else
 709     {
 710       set_current_inferior (inf);
 711       switch_to_thread (null_ptid);
 712       set_current_program_space (inf->pspace);
 713
 714       observer_notify_user_selected_context_changed (USER_SELECTED_INFERIOR);
 715     }
 716 }
 717
 718 /* Print information about currently known inferiors.  */
 719
 720 static void
 721 info_inferiors_command (const char *args, int from_tty)
 722 {
 723   print_inferior (current_uiout, args);
 724 }
 725
 726 /* remove-inferior ID */
 727
 728 static void
 729 remove_inferior_command (const char *args, int from_tty)
 730 {
 731   if (args == NULL || *args == '\0')
 732     error (_("Requires an argument (inferior id(s) to remove)"));
 733
 734   number_or_range_parser parser (args);
 735   while (!parser.finished ())
 736     {
 737       int num = parser.get_number ();
 738       struct inferior *inf = find_inferior_id (num);
 739
 740       if (inf == NULL)
 741         {
 742           warning (_("Inferior ID %d not known."), num);
 743           continue;
 744         }
 745
 746       if (!inf->deletable ())
 747         {
 748           warning (_("Can not remove current inferior %d."), num);
 749           continue;
 750         }
 751
 752       if (inf->pid != 0)
 753         {
 754           warning (_("Can not remove active inferior %d."), num);
 755           continue;
 756         }
 757
 758       delete_inferior (inf);
 759     }
 760 }
 761
 762 struct inferior *
 763 add_inferior_with_spaces (void)
 764 {
 765   struct address_space *aspace;
 766   struct program_space *pspace;
 767   struct inferior *inf;
 768   struct gdbarch_info info;
 769
 770   /* If all inferiors share an address space on this system, this
 771      doesn't really return a new address space; otherwise, it
 772      really does.  */
 773   aspace = maybe_new_address_space ();
 774   pspace = add_program_space (aspace);
 775   inf = add_inferior (0);
 776   inf->pspace = pspace;
 777   inf->aspace = pspace->aspace;
 778
 779   /* Setup the inferior's initial arch, based on information obtained
 780      from the global "set ..." options.  */
 781   gdbarch_info_init (&info);
 782   inf->gdbarch = gdbarch_find_by_info (info);
 783   /* The "set ..." options reject invalid settings, so we should
 784      always have a valid arch by now.  */
 785   gdb_assert (inf->gdbarch != NULL);
 786
 787   return inf;
 788 }
 789
 790 /* add-inferior [-copies N] [-exec FILENAME]  */
 791
 792 static void
 793 add_inferior_command (const char *args, int from_tty)
 794 {
 795   int i, copies = 1;
 796   gdb::unique_xmalloc_ptr<char> exec;
 797   symfile_add_flags add_flags = 0;
 798
 799   if (from_tty)
 800     add_flags |= SYMFILE_VERBOSE;
 801
 802   if (args)
 803     {
 804       gdb_argv built_argv (args);
 805
 806       for (char **argv = built_argv.get (); *argv != NULL; argv++)
 807         {
 808           if (**argv == '-')
 809             {
 810               if (strcmp (*argv, "-copies") == 0)
 811                 {
 812                   ++argv;
 813                   if (!*argv)
 814                     error (_("No argument to -copies"));
 815                   copies = parse_and_eval_long (*argv);
 816                 }
 817               else if (strcmp (*argv, "-exec") == 0)
 818                 {
 819                   ++argv;
 820                   if (!*argv)
 821                     error (_("No argument to -exec"));
 822                   exec.reset (tilde_expand (*argv));
 823                 }
 824             }
 825           else
 826             error (_("Invalid argument"));
 827         }
 828     }
 829
 830   scoped_restore_current_pspace_and_thread restore_pspace_thread;
 831
 832   for (i = 0; i < copies; ++i)
 833     {
 834       struct inferior *inf = add_inferior_with_spaces ();
 835
 836       printf_filtered (_("Added inferior %d\n"), inf->num);
 837
 838       if (exec != NULL)
 839         {
 840           /* Switch over temporarily, while reading executable and
 841              symbols.q.  */
 842           set_current_program_space (inf->pspace);
 843           set_current_inferior (inf);
 844           switch_to_thread (null_ptid);
 845
 846           exec_file_attach (exec.get (), from_tty);
 847           symbol_file_add_main (exec.get (), add_flags);
 848         }
 849     }
 850 }
 851
 852 /* clone-inferior [-copies N] [ID] */
 853
 854 static void
 855 clone_inferior_command (const char *args, int from_tty)
 856 {
 857   int i, copies = 1;
 858   struct inferior *orginf = NULL;
 859
 860   if (args)
 861     {
 862       gdb_argv built_argv (args);
 863
 864       char **argv = built_argv.get ();
 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                   if (copies < 0)
 877                     error (_("Invalid copies number"));
 878                 }
 879             }
 880           else
 881             {
 882               if (orginf == NULL)
 883                 {
 884                   int num;
 885
 886                   /* The first non-option (-) argument specified the
 887                      program space ID.  */
 888                   num = parse_and_eval_long (*argv);
 889                   orginf = find_inferior_id (num);
 890
 891                   if (orginf == NULL)
 892                     error (_("Inferior ID %d not known."), num);
 893                   continue;
 894                 }
 895               else
 896                 error (_("Invalid argument"));
 897             }
 898         }
 899     }
 900
 901   /* If no inferior id was specified, then the user wants to clone the
 902      current inferior.  */
 903   if (orginf == NULL)
 904     orginf = current_inferior ();
 905
 906   scoped_restore_current_pspace_and_thread restore_pspace_thread;
 907
 908   for (i = 0; i < copies; ++i)
 909     {
 910       struct address_space *aspace;
 911       struct program_space *pspace;
 912       struct inferior *inf;
 913
 914       /* If all inferiors share an address space on this system, this
 915          doesn't really return a new address space; otherwise, it
 916          really does.  */
 917       aspace = maybe_new_address_space ();
 918       pspace = add_program_space (aspace);
 919       inf = add_inferior (0);
 920       inf->pspace = pspace;
 921       inf->aspace = pspace->aspace;
 922       inf->gdbarch = orginf->gdbarch;
 923
 924       /* If the original inferior had a user specified target
 925          description, make the clone use it too.  */
 926       if (target_desc_info_from_user_p (inf->tdesc_info))
 927         copy_inferior_target_desc_info (inf, orginf);
 928
 929       printf_filtered (_("Added inferior %d.\n"), inf->num);
 930
 931       set_current_inferior (inf);
 932       switch_to_thread (null_ptid);
 933       clone_program_space (pspace, orginf->pspace);
 934     }
 935 }
 936
 937 /* Print notices when new inferiors are created and die.  */
 938 static void
 939 show_print_inferior_events (struct ui_file *file, int from_tty,
 940                            struct cmd_list_element *c, const char *value)
 941 {
 942   fprintf_filtered (file, _("Printing of inferior events is %s.\n"), value);
 943 }
 944
 945 /* Return a new value for the selected inferior's id.  */
 946
 947 static struct value *
 948 inferior_id_make_value (struct gdbarch *gdbarch, struct internalvar *var,
 949                         void *ignore)
 950 {
 951   struct inferior *inf = current_inferior ();
 952
 953   return value_from_longest (builtin_type (gdbarch)->builtin_int, inf->num);
 954 }
 955
 956 /* Implementation of `$_inferior' variable.  */
 957
 958 static const struct internalvar_funcs inferior_funcs =
 959 {
 960   inferior_id_make_value,
 961   NULL,
 962   NULL
 963 };
 964
 965 \f
 966
 967 void
 968 initialize_inferiors (void)
 969 {
 970   struct cmd_list_element *c = NULL;
 971
 972   /* There's always one inferior.  Note that this function isn't an
 973      automatic _initialize_foo function, since other _initialize_foo
 974      routines may need to install their per-inferior data keys.  We
 975      can only allocate an inferior when all those modules have done
 976      that.  Do this after initialize_progspace, due to the
 977      current_program_space reference.  */
 978   current_inferior_ = add_inferior (0);
 979   current_inferior_->incref ();
 980   current_inferior_->pspace = current_program_space;
 981   current_inferior_->aspace = current_program_space->aspace;
 982   /* The architecture will be initialized shortly, by
 983      initialize_current_architecture.  */
 984
 985   add_info ("inferiors", info_inferiors_command,
 986             _("IDs of specified inferiors (all inferiors if no argument)."));
 987
 988   c = add_com ("add-inferior", no_class, add_inferior_command, _("\
 989 Add a new inferior.\n\
 990 Usage: add-inferior [-copies <N>] [-exec <FILENAME>]\n\
 991 N is the optional number of inferiors to add, default is 1.\n\
 992 FILENAME is the file name of the executable to use\n\
 993 as main program."));
 994   set_cmd_completer (c, filename_completer);
 995
 996   add_com ("remove-inferiors", no_class, remove_inferior_command, _("\
 997 Remove inferior ID (or list of IDs).\n\
 998 Usage: remove-inferiors ID..."));
 999
1000   add_com ("clone-inferior", no_class, clone_inferior_command, _("\
1001 Clone inferior ID.\n\
1002 Usage: clone-inferior [-copies <N>] [ID]\n\
1003 Add N copies of inferior ID.  The new inferior has the same\n\
1004 executable loaded as the copied inferior.  If -copies is not specified,\n\
1005 adds 1 copy.  If ID is not specified, it is the current inferior\n\
1006 that is cloned."));
1007
1008   add_cmd ("inferiors", class_run, detach_inferior_command, _("\
1009 Detach from inferior ID (or list of IDS)."),
1010            &detachlist);
1011
1012   add_cmd ("inferiors", class_run, kill_inferior_command, _("\
1013 Kill inferior ID (or list of IDs)."),
1014            &killlist);
1015
1016   add_cmd ("inferior", class_run, inferior_command, _("\
1017 Use this command to switch between inferiors.\n\
1018 The new inferior ID must be currently known."),
1019            &cmdlist);
1020
1021   add_setshow_boolean_cmd ("inferior-events", no_class,
1022          &print_inferior_events, _("\
1023 Set printing of inferior events (e.g., inferior start and exit)."), _("\
1024 Show printing of inferior events (e.g., inferior start and exit)."), NULL,
1025          NULL,
1026          show_print_inferior_events,
1027          &setprintlist, &showprintlist);
1028
1029   create_internalvar_type_lazy ("_inferior", &inferior_funcs, NULL);
1030 }