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