gdb/inferior.c

   1 /* Multi-process control for GDB, the GNU debugger.
   2
   3    Copyright (C) 2008-2019 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 "observable.h"
  30 #include "gdbcore.h"
  31 #include "symfile.h"
  32 #include "gdbsupport/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 /* See inferior.h.  */
  49 bool print_inferior_events = true;
  50
  51 /* The Current Inferior.  This is a strong reference.  I.e., whenever
  52    an inferior is the current inferior, its refcount is
  53    incremented.  */
  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   inf->incref ();
  69   current_inferior_->decref ();
  70   current_inferior_ = inf;
  71 }
  72
  73 private_inferior::~private_inferior () = default;
  74
  75 inferior::~inferior ()
  76 {
  77   inferior *inf = this;
  78
  79   discard_all_inferior_continuations (inf);
  80   inferior_free_data (inf);
  81   xfree (inf->args);
  82   xfree (inf->terminal);
  83   target_desc_info_free (inf->tdesc_info);
  84 }
  85
  86 inferior::inferior (int pid_)
  87   : num (++highest_inferior_num),
  88     pid (pid_),
  89     environment (gdb_environ::from_host_environ ()),
  90     registry_data ()
  91 {
  92   inferior_alloc_data (this);
  93 }
  94
  95 struct inferior *
  96 add_inferior_silent (int pid)
  97 {
  98   inferior *inf = new inferior (pid);
  99
 100   if (inferior_list == NULL)
 101     inferior_list = inf;
 102   else
 103     {
 104       inferior *last;
 105
 106       for (last = inferior_list; last->next != NULL; last = last->next)
 107         ;
 108       last->next = inf;
 109     }
 110
 111   gdb::observers::inferior_added.notify (inf);
 112
 113   if (pid != 0)
 114     inferior_appeared (inf, pid);
 115
 116   return inf;
 117 }
 118
 119 struct inferior *
 120 add_inferior (int pid)
 121 {
 122   struct inferior *inf = add_inferior_silent (pid);
 123
 124   if (print_inferior_events)
 125     {
 126       if (pid != 0)
 127         printf_unfiltered (_("[New inferior %d (%s)]\n"),
 128                            inf->num,
 129                            target_pid_to_str (ptid_t (pid)).c_str ());
 130       else
 131         printf_unfiltered (_("[New inferior %d]\n"), inf->num);
 132     }
 133
 134   return inf;
 135 }
 136
 137 void
 138 delete_inferior (struct inferior *todel)
 139 {
 140   struct inferior *inf, *infprev;
 141
 142   infprev = NULL;
 143
 144   for (inf = inferior_list; inf; infprev = inf, inf = inf->next)
 145     if (inf == todel)
 146       break;
 147
 148   if (!inf)
 149     return;
 150
 151   for (thread_info *tp : inf->threads ())
 152     delete_thread_silent_noremove (tp);
 153
 154   if (infprev)
 155     infprev->next = inf->next;
 156   else
 157     inferior_list = inf->next;
 158
 159   gdb::observers::inferior_removed.notify (inf);
 160
 161   /* If this program space is rendered useless, remove it. */
 162   if (program_space_empty_p (inf->pspace))
 163     delete_program_space (inf->pspace);
 164
 165   delete inf;
 166 }
 167
 168 /* If SILENT then be quiet -- don't announce a inferior exit, or the
 169    exit of its threads.  */
 170
 171 static void
 172 exit_inferior_1 (struct inferior *inftoex, int silent)
 173 {
 174   struct inferior *inf;
 175
 176   for (inf = inferior_list; inf; inf = inf->next)
 177     if (inf == inftoex)
 178       break;
 179
 180   if (!inf)
 181     return;
 182
 183   for (thread_info *tp : inf->threads ())
 184     {
 185       if (silent)
 186         delete_thread_silent_noremove (tp);
 187       else
 188         delete_thread_noremove (tp);
 189     }
 190
 191   inf->thread_map.clear ();
 192
 193   gdb::observers::inferior_exit.notify (inf);
 194
 195   inf->pid = 0;
 196   inf->fake_pid_p = false;
 197   inf->priv = NULL;
 198
 199   if (inf->vfork_parent != NULL)
 200     {
 201       inf->vfork_parent->vfork_child = NULL;
 202       inf->vfork_parent = NULL;
 203     }
 204   if (inf->vfork_child != NULL)
 205     {
 206       inf->vfork_child->vfork_parent = NULL;
 207       inf->vfork_child = NULL;
 208     }
 209
 210   inf->pending_detach = 0;
 211   /* Reset it.  */
 212   inf->control = inferior_control_state (NO_STOP_QUIETLY);
 213
 214   /* Clear the register cache and the frame cache.  */
 215   registers_changed ();
 216   reinit_frame_cache ();
 217 }
 218
 219 void
 220 exit_inferior (inferior *inf)
 221 {
 222   exit_inferior_1 (inf, 0);
 223 }
 224
 225 void
 226 exit_inferior_silent (inferior *inf)
 227 {
 228   exit_inferior_1 (inf, 1);
 229 }
 230
 231 /* See inferior.h.  */
 232
 233 void
 234 detach_inferior (inferior *inf)
 235 {
 236   /* Save the pid, since exit_inferior_1 will reset it.  */
 237   int pid = inf->pid;
 238
 239   exit_inferior_1 (inf, 0);
 240
 241   if (print_inferior_events)
 242     printf_unfiltered (_("[Inferior %d (%s) detached]\n"),
 243                        inf->num,
 244                        target_pid_to_str (ptid_t (pid)).c_str ());
 245 }
 246
 247 void
 248 inferior_appeared (struct inferior *inf, int pid)
 249 {
 250   /* If this is the first inferior with threads, reset the global
 251      thread id.  */
 252   if (!any_thread_p ())
 253     init_thread_list ();
 254
 255   inf->pid = pid;
 256   inf->has_exit_code = 0;
 257   inf->exit_code = 0;
 258
 259   gdb::observers::inferior_appeared.notify (inf);
 260 }
 261
 262 void
 263 discard_all_inferiors (void)
 264 {
 265   for (inferior *inf : all_non_exited_inferiors ())
 266     exit_inferior_silent (inf);
 267 }
 268
 269 struct inferior *
 270 find_inferior_id (int num)
 271 {
 272   for (inferior *inf : all_inferiors ())
 273     if (inf->num == num)
 274       return inf;
 275
 276   return NULL;
 277 }
 278
 279 struct inferior *
 280 find_inferior_pid (int pid)
 281 {
 282   /* Looking for inferior pid == 0 is always wrong, and indicative of
 283      a bug somewhere else.  There may be more than one with pid == 0,
 284      for instance.  */
 285   gdb_assert (pid != 0);
 286
 287   for (inferior *inf : all_inferiors ())
 288     if (inf->pid == pid)
 289       return inf;
 290
 291   return NULL;
 292 }
 293
 294 /* See inferior.h */
 295
 296 struct inferior *
 297 find_inferior_ptid (ptid_t ptid)
 298 {
 299   return find_inferior_pid (ptid.pid ());
 300 }
 301
 302 /* See inferior.h.  */
 303
 304 struct inferior *
 305 find_inferior_for_program_space (struct program_space *pspace)
 306 {
 307   struct inferior *cur_inf = current_inferior ();
 308
 309   if (cur_inf->pspace == pspace)
 310     return cur_inf;
 311
 312   for (inferior *inf : all_inferiors ())
 313     if (inf->pspace == pspace)
 314       return inf;
 315
 316   return NULL;
 317 }
 318
 319 struct inferior *
 320 iterate_over_inferiors (int (*callback) (struct inferior *, void *),
 321                         void *data)
 322 {
 323   for (inferior *inf : all_inferiors_safe ())
 324     if ((*callback) (inf, data))
 325       return inf;
 326
 327   return NULL;
 328 }
 329
 330 int
 331 have_inferiors (void)
 332 {
 333   for (inferior *inf ATTRIBUTE_UNUSED : all_non_exited_inferiors ())
 334     return 1;
 335
 336   return 0;
 337 }
 338
 339 /* Return the number of live inferiors.  We account for the case
 340    where an inferior might have a non-zero pid but no threads, as
 341    in the middle of a 'mourn' operation.  */
 342
 343 int
 344 number_of_live_inferiors (void)
 345 {
 346   int num_inf = 0;
 347
 348   for (inferior *inf : all_non_exited_inferiors ())
 349     if (target_has_execution_1 (ptid_t (inf->pid)))
 350       for (thread_info *tp ATTRIBUTE_UNUSED : inf->non_exited_threads ())
 351         {
 352           /* Found a live thread in this inferior, go to the next
 353              inferior.  */
 354           ++num_inf;
 355           break;
 356         }
 357
 358   return num_inf;
 359 }
 360
 361 /* Return true if there is at least one live inferior.  */
 362
 363 int
 364 have_live_inferiors (void)
 365 {
 366   return number_of_live_inferiors () > 0;
 367 }
 368
 369 /* Prune away any unused inferiors, and then prune away no longer used
 370    program spaces.  */
 371
 372 void
 373 prune_inferiors (void)
 374 {
 375   inferior *ss;
 376
 377   ss = inferior_list;
 378   while (ss)
 379     {
 380       if (!ss->deletable ()
 381           || !ss->removable
 382           || ss->pid != 0)
 383         {
 384           ss = ss->next;
 385           continue;
 386         }
 387
 388       inferior *ss_next = ss->next;
 389       delete_inferior (ss);
 390       ss = ss_next;
 391     }
 392 }
 393
 394 /* Simply returns the count of inferiors.  */
 395
 396 int
 397 number_of_inferiors (void)
 398 {
 399   auto rng = all_inferiors ();
 400   return std::distance (rng.begin (), rng.end ());
 401 }
 402
 403 /* Converts an inferior process id to a string.  Like
 404    target_pid_to_str, but special cases the null process.  */
 405
 406 static std::string
 407 inferior_pid_to_str (int pid)
 408 {
 409   if (pid != 0)
 410     return target_pid_to_str (ptid_t (pid));
 411   else
 412     return _("<null>");
 413 }
 414
 415 /* See inferior.h.  */
 416
 417 void
 418 print_selected_inferior (struct ui_out *uiout)
 419 {
 420   struct inferior *inf = current_inferior ();
 421   const char *filename = inf->pspace->pspace_exec_filename;
 422
 423   if (filename == NULL)
 424     filename = _("<noexec>");
 425
 426   uiout->message (_("[Switching to inferior %d [%s] (%s)]\n"),
 427                   inf->num, inferior_pid_to_str (inf->pid).c_str (), filename);
 428 }
 429
 430 /* Prints the list of inferiors and their details on UIOUT.  This is a
 431    version of 'info_inferior_command' suitable for use from MI.
 432
 433    If REQUESTED_INFERIORS is not NULL, it's a list of GDB ids of the
 434    inferiors that should be printed.  Otherwise, all inferiors are
 435    printed.  */
 436
 437 static void
 438 print_inferior (struct ui_out *uiout, const char *requested_inferiors)
 439 {
 440   int inf_count = 0;
 441
 442   /* Compute number of inferiors we will print.  */
 443   for (inferior *inf : all_inferiors ())
 444     {
 445       if (!number_is_in_list (requested_inferiors, inf->num))
 446         continue;
 447
 448       ++inf_count;
 449     }
 450
 451   if (inf_count == 0)
 452     {
 453       uiout->message ("No inferiors.\n");
 454       return;
 455     }
 456
 457   ui_out_emit_table table_emitter (uiout, 4, inf_count, "inferiors");
 458   uiout->table_header (1, ui_left, "current", "");
 459   uiout->table_header (4, ui_left, "number", "Num");
 460   uiout->table_header (17, ui_left, "target-id", "Description");
 461   uiout->table_header (17, ui_left, "exec", "Executable");
 462
 463   uiout->table_body ();
 464   for (inferior *inf : all_inferiors ())
 465     {
 466       if (!number_is_in_list (requested_inferiors, inf->num))
 467         continue;
 468
 469       ui_out_emit_tuple tuple_emitter (uiout, NULL);
 470
 471       if (inf == current_inferior ())
 472         uiout->field_string ("current", "*");
 473       else
 474         uiout->field_skip ("current");
 475
 476       uiout->field_signed ("number", inf->num);
 477
 478       uiout->field_string ("target-id", inferior_pid_to_str (inf->pid));
 479
 480       if (inf->pspace->pspace_exec_filename != NULL)
 481         uiout->field_string ("exec", inf->pspace->pspace_exec_filename);
 482       else
 483         uiout->field_skip ("exec");
 484
 485       /* Print extra info that isn't really fit to always present in
 486          tabular form.  Currently we print the vfork parent/child
 487          relationships, if any.  */
 488       if (inf->vfork_parent)
 489         {
 490           uiout->text (_("\n\tis vfork child of inferior "));
 491           uiout->field_signed ("vfork-parent", inf->vfork_parent->num);
 492         }
 493       if (inf->vfork_child)
 494         {
 495           uiout->text (_("\n\tis vfork parent of inferior "));
 496           uiout->field_signed ("vfork-child", inf->vfork_child->num);
 497         }
 498
 499       uiout->text ("\n");
 500     }
 501 }
 502
 503 static void
 504 detach_inferior_command (const char *args, int from_tty)
 505 {
 506   if (!args || !*args)
 507     error (_("Requires argument (inferior id(s) to detach)"));
 508
 509   number_or_range_parser parser (args);
 510   while (!parser.finished ())
 511     {
 512       int num = parser.get_number ();
 513
 514       inferior *inf = find_inferior_id (num);
 515       if (inf == NULL)
 516         {
 517           warning (_("Inferior ID %d not known."), num);
 518           continue;
 519         }
 520
 521       if (inf->pid == 0)
 522         {
 523           warning (_("Inferior ID %d is not running."), num);
 524           continue;
 525         }
 526
 527       thread_info *tp = any_thread_of_inferior (inf);
 528       if (tp == NULL)
 529         {
 530           warning (_("Inferior ID %d has no threads."), num);
 531           continue;
 532         }
 533
 534       switch_to_thread (tp);
 535
 536       detach_command (NULL, from_tty);
 537     }
 538 }
 539
 540 static void
 541 kill_inferior_command (const char *args, int from_tty)
 542 {
 543   if (!args || !*args)
 544     error (_("Requires argument (inferior id(s) to kill)"));
 545
 546   number_or_range_parser parser (args);
 547   while (!parser.finished ())
 548     {
 549       int num = parser.get_number ();
 550
 551       inferior *inf = find_inferior_id (num);
 552       if (inf == NULL)
 553         {
 554           warning (_("Inferior ID %d not known."), num);
 555           continue;
 556         }
 557
 558       if (inf->pid == 0)
 559         {
 560           warning (_("Inferior ID %d is not running."), num);
 561           continue;
 562         }
 563
 564       thread_info *tp = any_thread_of_inferior (inf);
 565       if (tp == NULL)
 566         {
 567           warning (_("Inferior ID %d has no threads."), num);
 568           continue;
 569         }
 570
 571       switch_to_thread (tp);
 572
 573       target_kill ();
 574     }
 575
 576   bfd_cache_close_all ();
 577 }
 578
 579 static void
 580 inferior_command (const char *args, int from_tty)
 581 {
 582   struct inferior *inf;
 583   int num;
 584
 585   num = parse_and_eval_long (args);
 586
 587   inf = find_inferior_id (num);
 588   if (inf == NULL)
 589     error (_("Inferior ID %d not known."), num);
 590
 591   if (inf->pid != 0)
 592     {
 593       if (inf != current_inferior ())
 594         {
 595           thread_info *tp = first_thread_of_inferior (inf);
 596           if (tp == NULL)
 597             error (_("Inferior has no threads."));
 598
 599           switch_to_thread (tp);
 600         }
 601
 602       gdb::observers::user_selected_context_changed.notify
 603         (USER_SELECTED_INFERIOR
 604          | USER_SELECTED_THREAD
 605          | USER_SELECTED_FRAME);
 606     }
 607   else
 608     {
 609       set_current_inferior (inf);
 610       switch_to_no_thread ();
 611       set_current_program_space (inf->pspace);
 612
 613       gdb::observers::user_selected_context_changed.notify
 614         (USER_SELECTED_INFERIOR);
 615     }
 616 }
 617
 618 /* Print information about currently known inferiors.  */
 619
 620 static void
 621 info_inferiors_command (const char *args, int from_tty)
 622 {
 623   print_inferior (current_uiout, args);
 624 }
 625
 626 /* remove-inferior ID */
 627
 628 static void
 629 remove_inferior_command (const char *args, int from_tty)
 630 {
 631   if (args == NULL || *args == '\0')
 632     error (_("Requires an argument (inferior id(s) to remove)"));
 633
 634   number_or_range_parser parser (args);
 635   while (!parser.finished ())
 636     {
 637       int num = parser.get_number ();
 638       struct inferior *inf = find_inferior_id (num);
 639
 640       if (inf == NULL)
 641         {
 642           warning (_("Inferior ID %d not known."), num);
 643           continue;
 644         }
 645
 646       if (!inf->deletable ())
 647         {
 648           warning (_("Can not remove current inferior %d."), num);
 649           continue;
 650         }
 651
 652       if (inf->pid != 0)
 653         {
 654           warning (_("Can not remove active inferior %d."), num);
 655           continue;
 656         }
 657
 658       delete_inferior (inf);
 659     }
 660 }
 661
 662 struct inferior *
 663 add_inferior_with_spaces (void)
 664 {
 665   struct address_space *aspace;
 666   struct program_space *pspace;
 667   struct inferior *inf;
 668   struct gdbarch_info info;
 669
 670   /* If all inferiors share an address space on this system, this
 671      doesn't really return a new address space; otherwise, it
 672      really does.  */
 673   aspace = maybe_new_address_space ();
 674   pspace = new program_space (aspace);
 675   inf = add_inferior (0);
 676   inf->pspace = pspace;
 677   inf->aspace = pspace->aspace;
 678
 679   /* Setup the inferior's initial arch, based on information obtained
 680      from the global "set ..." options.  */
 681   gdbarch_info_init (&info);
 682   inf->gdbarch = gdbarch_find_by_info (info);
 683   /* The "set ..." options reject invalid settings, so we should
 684      always have a valid arch by now.  */
 685   gdb_assert (inf->gdbarch != NULL);
 686
 687   return inf;
 688 }
 689
 690 /* add-inferior [-copies N] [-exec FILENAME]  */
 691
 692 static void
 693 add_inferior_command (const char *args, int from_tty)
 694 {
 695   int i, copies = 1;
 696   gdb::unique_xmalloc_ptr<char> exec;
 697   symfile_add_flags add_flags = 0;
 698
 699   if (from_tty)
 700     add_flags |= SYMFILE_VERBOSE;
 701
 702   if (args)
 703     {
 704       gdb_argv built_argv (args);
 705
 706       for (char **argv = built_argv.get (); *argv != NULL; argv++)
 707         {
 708           if (**argv == '-')
 709             {
 710               if (strcmp (*argv, "-copies") == 0)
 711                 {
 712                   ++argv;
 713                   if (!*argv)
 714                     error (_("No argument to -copies"));
 715                   copies = parse_and_eval_long (*argv);
 716                 }
 717               else if (strcmp (*argv, "-exec") == 0)
 718                 {
 719                   ++argv;
 720                   if (!*argv)
 721                     error (_("No argument to -exec"));
 722                   exec.reset (tilde_expand (*argv));
 723                 }
 724             }
 725           else
 726             error (_("Invalid argument"));
 727         }
 728     }
 729
 730   scoped_restore_current_pspace_and_thread restore_pspace_thread;
 731
 732   for (i = 0; i < copies; ++i)
 733     {
 734       struct inferior *inf = add_inferior_with_spaces ();
 735
 736       printf_filtered (_("Added inferior %d\n"), inf->num);
 737
 738       if (exec != NULL)
 739         {
 740           /* Switch over temporarily, while reading executable and
 741              symbols.q.  */
 742           set_current_program_space (inf->pspace);
 743           set_current_inferior (inf);
 744           switch_to_no_thread ();
 745
 746           exec_file_attach (exec.get (), from_tty);
 747           symbol_file_add_main (exec.get (), add_flags);
 748         }
 749     }
 750 }
 751
 752 /* clone-inferior [-copies N] [ID] */
 753
 754 static void
 755 clone_inferior_command (const char *args, int from_tty)
 756 {
 757   int i, copies = 1;
 758   struct inferior *orginf = NULL;
 759
 760   if (args)
 761     {
 762       gdb_argv built_argv (args);
 763
 764       char **argv = built_argv.get ();
 765       for (; *argv != NULL; argv++)
 766         {
 767           if (**argv == '-')
 768             {
 769               if (strcmp (*argv, "-copies") == 0)
 770                 {
 771                   ++argv;
 772                   if (!*argv)
 773                     error (_("No argument to -copies"));
 774                   copies = parse_and_eval_long (*argv);
 775
 776                   if (copies < 0)
 777                     error (_("Invalid copies number"));
 778                 }
 779             }
 780           else
 781             {
 782               if (orginf == NULL)
 783                 {
 784                   int num;
 785
 786                   /* The first non-option (-) argument specified the
 787                      program space ID.  */
 788                   num = parse_and_eval_long (*argv);
 789                   orginf = find_inferior_id (num);
 790
 791                   if (orginf == NULL)
 792                     error (_("Inferior ID %d not known."), num);
 793                   continue;
 794                 }
 795               else
 796                 error (_("Invalid argument"));
 797             }
 798         }
 799     }
 800
 801   /* If no inferior id was specified, then the user wants to clone the
 802      current inferior.  */
 803   if (orginf == NULL)
 804     orginf = current_inferior ();
 805
 806   scoped_restore_current_pspace_and_thread restore_pspace_thread;
 807
 808   for (i = 0; i < copies; ++i)
 809     {
 810       struct address_space *aspace;
 811       struct program_space *pspace;
 812       struct inferior *inf;
 813
 814       /* If all inferiors share an address space on this system, this
 815          doesn't really return a new address space; otherwise, it
 816          really does.  */
 817       aspace = maybe_new_address_space ();
 818       pspace = new program_space (aspace);
 819       inf = add_inferior (0);
 820       inf->pspace = pspace;
 821       inf->aspace = pspace->aspace;
 822       inf->gdbarch = orginf->gdbarch;
 823
 824       /* If the original inferior had a user specified target
 825          description, make the clone use it too.  */
 826       if (target_desc_info_from_user_p (inf->tdesc_info))
 827         copy_inferior_target_desc_info (inf, orginf);
 828
 829       printf_filtered (_("Added inferior %d.\n"), inf->num);
 830
 831       set_current_inferior (inf);
 832       switch_to_no_thread ();
 833       clone_program_space (pspace, orginf->pspace);
 834     }
 835 }
 836
 837 /* Print notices when new inferiors are created and die.  */
 838 static void
 839 show_print_inferior_events (struct ui_file *file, int from_tty,
 840                            struct cmd_list_element *c, const char *value)
 841 {
 842   fprintf_filtered (file, _("Printing of inferior events is %s.\n"), value);
 843 }
 844
 845 /* Return a new value for the selected inferior's id.  */
 846
 847 static struct value *
 848 inferior_id_make_value (struct gdbarch *gdbarch, struct internalvar *var,
 849                         void *ignore)
 850 {
 851   struct inferior *inf = current_inferior ();
 852
 853   return value_from_longest (builtin_type (gdbarch)->builtin_int, inf->num);
 854 }
 855
 856 /* Implementation of `$_inferior' variable.  */
 857
 858 static const struct internalvar_funcs inferior_funcs =
 859 {
 860   inferior_id_make_value,
 861   NULL,
 862   NULL
 863 };
 864
 865 \f
 866
 867 void
 868 initialize_inferiors (void)
 869 {
 870   struct cmd_list_element *c = NULL;
 871
 872   /* There's always one inferior.  Note that this function isn't an
 873      automatic _initialize_foo function, since other _initialize_foo
 874      routines may need to install their per-inferior data keys.  We
 875      can only allocate an inferior when all those modules have done
 876      that.  Do this after initialize_progspace, due to the
 877      current_program_space reference.  */
 878   current_inferior_ = add_inferior_silent (0);
 879   current_inferior_->incref ();
 880   current_inferior_->pspace = current_program_space;
 881   current_inferior_->aspace = current_program_space->aspace;
 882   /* The architecture will be initialized shortly, by
 883      initialize_current_architecture.  */
 884
 885   add_info ("inferiors", info_inferiors_command,
 886             _("Print a list of inferiors being managed.\n\
 887 Usage: info inferiors [ID]...\n\
 888 If IDs are specified, the list is limited to just those inferiors.\n\
 889 By default all inferiors are displayed."));
 890
 891   c = add_com ("add-inferior", no_class, add_inferior_command, _("\
 892 Add a new inferior.\n\
 893 Usage: add-inferior [-copies N] [-exec FILENAME]\n\
 894 N is the optional number of inferiors to add, default is 1.\n\
 895 FILENAME is the file name of the executable to use\n\
 896 as main program."));
 897   set_cmd_completer (c, filename_completer);
 898
 899   add_com ("remove-inferiors", no_class, remove_inferior_command, _("\
 900 Remove inferior ID (or list of IDs).\n\
 901 Usage: remove-inferiors ID..."));
 902
 903   add_com ("clone-inferior", no_class, clone_inferior_command, _("\
 904 Clone inferior ID.\n\
 905 Usage: clone-inferior [-copies N] [ID]\n\
 906 Add N copies of inferior ID.  The new inferior has the same\n\
 907 executable loaded as the copied inferior.  If -copies is not specified,\n\
 908 adds 1 copy.  If ID is not specified, it is the current inferior\n\
 909 that is cloned."));
 910
 911   add_cmd ("inferiors", class_run, detach_inferior_command, _("\
 912 Detach from inferior ID (or list of IDS).\n\
 913 Usage; detach inferiors ID..."),
 914            &detachlist);
 915
 916   add_cmd ("inferiors", class_run, kill_inferior_command, _("\
 917 Kill inferior ID (or list of IDs).\n\
 918 Usage: kill inferiors ID..."),
 919            &killlist);
 920
 921   add_cmd ("inferior", class_run, inferior_command, _("\
 922 Use this command to switch between inferiors.\n\
 923 Usage: inferior ID\n\
 924 The new inferior ID must be currently known."),
 925            &cmdlist);
 926
 927   add_setshow_boolean_cmd ("inferior-events", no_class,
 928          &print_inferior_events, _("\
 929 Set printing of inferior events (such as inferior start and exit)."), _("\
 930 Show printing of inferior events (such as inferior start and exit)."), NULL,
 931          NULL,
 932          show_print_inferior_events,
 933          &setprintlist, &showprintlist);
 934
 935   create_internalvar_type_lazy ("_inferior", &inferior_funcs, NULL);
 936 }