gdb/thread.c

   1 /* Multi-process/thread control for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2014 Free Software Foundation, Inc.
   4
   5    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "symtab.h"
  24 #include "frame.h"
  25 #include "inferior.h"
  26 #include "environ.h"
  27 #include "value.h"
  28 #include "target.h"
  29 #include "gdbthread.h"
  30 #include "command.h"
  31 #include "gdbcmd.h"
  32 #include "regcache.h"
  33 #include "gdb.h"
  34 #include "btrace.h"
  35
  36 #include <ctype.h>
  37 #include <sys/types.h>
  38 #include <signal.h>
  39 #include "ui-out.h"
  40 #include "observer.h"
  41 #include "annotate.h"
  42 #include "cli/cli-decode.h"
  43 #include "gdb_regex.h"
  44 #include "cli/cli-utils.h"
  45 #include "continuations.h"
  46
  47 /* Definition of struct thread_info exported to gdbthread.h.  */
  48
  49 /* Prototypes for exported functions.  */
  50
  51 void _initialize_thread (void);
  52
  53 /* Prototypes for local functions.  */
  54
  55 struct thread_info *thread_list = NULL;
  56 static int highest_thread_num;
  57
  58 /* True if any thread is, or may be executing.  We need to track this
  59    separately because until we fully sync the thread list, we won't
  60    know whether the target is fully stopped, even if we see stop
  61    events for all known threads, because any of those threads may have
  62    spawned new threads we haven't heard of yet.  */
  63 static int threads_executing;
  64
  65 static void thread_command (char *tidstr, int from_tty);
  66 static void thread_apply_all_command (char *, int);
  67 static int thread_alive (struct thread_info *);
  68 static void info_threads_command (char *, int);
  69 static void thread_apply_command (char *, int);
  70 static void restore_current_thread (ptid_t);
  71 static void prune_threads (void);
  72
  73 /* Data to cleanup thread array.  */
  74
  75 struct thread_array_cleanup
  76 {
  77   /* Array of thread pointers used to set
  78      reference count.  */
  79   struct thread_info **tp_array;
  80
  81   /* Thread count in the array.  */
  82   int count;
  83 };
  84
  85
  86 struct thread_info*
  87 inferior_thread (void)
  88 {
  89   struct thread_info *tp = find_thread_ptid (inferior_ptid);
  90   gdb_assert (tp);
  91   return tp;
  92 }
  93
  94 /* Delete the breakpoint pointed at by BP_P, if there's one.  */
  95
  96 static void
  97 delete_thread_breakpoint (struct breakpoint **bp_p)
  98 {
  99   if (*bp_p != NULL)
 100     {
 101       delete_breakpoint (*bp_p);
 102       *bp_p = NULL;
 103     }
 104 }
 105
 106 void
 107 delete_step_resume_breakpoint (struct thread_info *tp)
 108 {
 109   if (tp != NULL)
 110     delete_thread_breakpoint (&tp->control.step_resume_breakpoint);
 111 }
 112
 113 void
 114 delete_exception_resume_breakpoint (struct thread_info *tp)
 115 {
 116   if (tp != NULL)
 117     delete_thread_breakpoint (&tp->control.exception_resume_breakpoint);
 118 }
 119
 120 /* Delete the breakpoint pointed at by BP_P at the next stop, if
 121    there's one.  */
 122
 123 static void
 124 delete_at_next_stop (struct breakpoint **bp)
 125 {
 126   if (*bp != NULL)
 127     {
 128       (*bp)->disposition = disp_del_at_next_stop;
 129       *bp = NULL;
 130     }
 131 }
 132
 133 static void
 134 clear_thread_inferior_resources (struct thread_info *tp)
 135 {
 136   /* NOTE: this will take care of any left-over step_resume breakpoints,
 137      but not any user-specified thread-specific breakpoints.  We can not
 138      delete the breakpoint straight-off, because the inferior might not
 139      be stopped at the moment.  */
 140   delete_at_next_stop (&tp->control.step_resume_breakpoint);
 141   delete_at_next_stop (&tp->control.exception_resume_breakpoint);
 142
 143   delete_longjmp_breakpoint_at_next_stop (tp->num);
 144
 145   bpstat_clear (&tp->control.stop_bpstat);
 146
 147   btrace_teardown (tp);
 148
 149   do_all_intermediate_continuations_thread (tp, 1);
 150   do_all_continuations_thread (tp, 1);
 151 }
 152
 153 static void
 154 free_thread (struct thread_info *tp)
 155 {
 156   if (tp->private)
 157     {
 158       if (tp->private_dtor)
 159         tp->private_dtor (tp->private);
 160       else
 161         xfree (tp->private);
 162     }
 163
 164   xfree (tp->name);
 165   xfree (tp);
 166 }
 167
 168 void
 169 init_thread_list (void)
 170 {
 171   struct thread_info *tp, *tpnext;
 172
 173   highest_thread_num = 0;
 174
 175   if (!thread_list)
 176     return;
 177
 178   for (tp = thread_list; tp; tp = tpnext)
 179     {
 180       tpnext = tp->next;
 181       free_thread (tp);
 182     }
 183
 184   thread_list = NULL;
 185   threads_executing = 0;
 186 }
 187
 188 /* Allocate a new thread with target id PTID and add it to the thread
 189    list.  */
 190
 191 static struct thread_info *
 192 new_thread (ptid_t ptid)
 193 {
 194   struct thread_info *tp;
 195
 196   tp = xcalloc (1, sizeof (*tp));
 197
 198   tp->ptid = ptid;
 199   tp->num = ++highest_thread_num;
 200   tp->next = thread_list;
 201   thread_list = tp;
 202
 203   /* Nothing to follow yet.  */
 204   tp->pending_follow.kind = TARGET_WAITKIND_SPURIOUS;
 205   tp->state = THREAD_STOPPED;
 206
 207   return tp;
 208 }
 209
 210 struct thread_info *
 211 add_thread_silent (ptid_t ptid)
 212 {
 213   struct thread_info *tp;
 214
 215   tp = find_thread_ptid (ptid);
 216   if (tp)
 217     /* Found an old thread with the same id.  It has to be dead,
 218        otherwise we wouldn't be adding a new thread with the same id.
 219        The OS is reusing this id --- delete it, and recreate a new
 220        one.  */
 221     {
 222       /* In addition to deleting the thread, if this is the current
 223          thread, then we need to take care that delete_thread doesn't
 224          really delete the thread if it is inferior_ptid.  Create a
 225          new template thread in the list with an invalid ptid, switch
 226          to it, delete the original thread, reset the new thread's
 227          ptid, and switch to it.  */
 228
 229       if (ptid_equal (inferior_ptid, ptid))
 230         {
 231           tp = new_thread (null_ptid);
 232
 233           /* Make switch_to_thread not read from the thread.  */
 234           tp->state = THREAD_EXITED;
 235           switch_to_thread (null_ptid);
 236
 237           /* Now we can delete it.  */
 238           delete_thread (ptid);
 239
 240           /* Now reset its ptid, and reswitch inferior_ptid to it.  */
 241           tp->ptid = ptid;
 242           tp->state = THREAD_STOPPED;
 243           switch_to_thread (ptid);
 244
 245           observer_notify_new_thread (tp);
 246
 247           /* All done.  */
 248           return tp;
 249         }
 250       else
 251         /* Just go ahead and delete it.  */
 252         delete_thread (ptid);
 253     }
 254
 255   tp = new_thread (ptid);
 256   observer_notify_new_thread (tp);
 257
 258   return tp;
 259 }
 260
 261 struct thread_info *
 262 add_thread_with_info (ptid_t ptid, struct private_thread_info *private)
 263 {
 264   struct thread_info *result = add_thread_silent (ptid);
 265
 266   result->private = private;
 267
 268   if (print_thread_events)
 269     printf_unfiltered (_("[New %s]\n"), target_pid_to_str (ptid));
 270
 271   annotate_new_thread ();
 272   return result;
 273 }
 274
 275 struct thread_info *
 276 add_thread (ptid_t ptid)
 277 {
 278   return add_thread_with_info (ptid, NULL);
 279 }
 280
 281 /* Delete thread PTID.  If SILENT, don't notify the observer of this
 282    exit.  */
 283 static void
 284 delete_thread_1 (ptid_t ptid, int silent)
 285 {
 286   struct thread_info *tp, *tpprev;
 287
 288   tpprev = NULL;
 289
 290   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 291     if (ptid_equal (tp->ptid, ptid))
 292       break;
 293
 294   if (!tp)
 295     return;
 296
 297   /* If this is the current thread, or there's code out there that
 298      relies on it existing (refcount > 0) we can't delete yet.  Mark
 299      it as exited, and notify it.  */
 300   if (tp->refcount > 0
 301       || ptid_equal (tp->ptid, inferior_ptid))
 302     {
 303       if (tp->state != THREAD_EXITED)
 304         {
 305           observer_notify_thread_exit (tp, silent);
 306
 307           /* Tag it as exited.  */
 308           tp->state = THREAD_EXITED;
 309
 310           /* Clear breakpoints, etc. associated with this thread.  */
 311           clear_thread_inferior_resources (tp);
 312         }
 313
 314        /* Will be really deleted some other time.  */
 315        return;
 316      }
 317
 318   /* Notify thread exit, but only if we haven't already.  */
 319   if (tp->state != THREAD_EXITED)
 320     observer_notify_thread_exit (tp, silent);
 321
 322   /* Tag it as exited.  */
 323   tp->state = THREAD_EXITED;
 324   clear_thread_inferior_resources (tp);
 325
 326   if (tpprev)
 327     tpprev->next = tp->next;
 328   else
 329     thread_list = tp->next;
 330
 331   free_thread (tp);
 332 }
 333
 334 /* Delete thread PTID and notify of thread exit.  If this is
 335    inferior_ptid, don't actually delete it, but tag it as exited and
 336    do the notification.  If PTID is the user selected thread, clear
 337    it.  */
 338 void
 339 delete_thread (ptid_t ptid)
 340 {
 341   delete_thread_1 (ptid, 0 /* not silent */);
 342 }
 343
 344 void
 345 delete_thread_silent (ptid_t ptid)
 346 {
 347   delete_thread_1 (ptid, 1 /* silent */);
 348 }
 349
 350 struct thread_info *
 351 find_thread_id (int num)
 352 {
 353   struct thread_info *tp;
 354
 355   for (tp = thread_list; tp; tp = tp->next)
 356     if (tp->num == num)
 357       return tp;
 358
 359   return NULL;
 360 }
 361
 362 /* Find a thread_info by matching PTID.  */
 363 struct thread_info *
 364 find_thread_ptid (ptid_t ptid)
 365 {
 366   struct thread_info *tp;
 367
 368   for (tp = thread_list; tp; tp = tp->next)
 369     if (ptid_equal (tp->ptid, ptid))
 370       return tp;
 371
 372   return NULL;
 373 }
 374
 375 /*
 376  * Thread iterator function.
 377  *
 378  * Calls a callback function once for each thread, so long as
 379  * the callback function returns false.  If the callback function
 380  * returns true, the iteration will end and the current thread
 381  * will be returned.  This can be useful for implementing a
 382  * search for a thread with arbitrary attributes, or for applying
 383  * some operation to every thread.
 384  *
 385  * FIXME: some of the existing functionality, such as
 386  * "Thread apply all", might be rewritten using this functionality.
 387  */
 388
 389 struct thread_info *
 390 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 391                       void *data)
 392 {
 393   struct thread_info *tp, *next;
 394
 395   for (tp = thread_list; tp; tp = next)
 396     {
 397       next = tp->next;
 398       if ((*callback) (tp, data))
 399         return tp;
 400     }
 401
 402   return NULL;
 403 }
 404
 405 int
 406 thread_count (void)
 407 {
 408   int result = 0;
 409   struct thread_info *tp;
 410
 411   for (tp = thread_list; tp; tp = tp->next)
 412     ++result;
 413
 414   return result;
 415 }
 416
 417 int
 418 valid_thread_id (int num)
 419 {
 420   struct thread_info *tp;
 421
 422   for (tp = thread_list; tp; tp = tp->next)
 423     if (tp->num == num)
 424       return 1;
 425
 426   return 0;
 427 }
 428
 429 int
 430 pid_to_thread_id (ptid_t ptid)
 431 {
 432   struct thread_info *tp;
 433
 434   for (tp = thread_list; tp; tp = tp->next)
 435     if (ptid_equal (tp->ptid, ptid))
 436       return tp->num;
 437
 438   return 0;
 439 }
 440
 441 ptid_t
 442 thread_id_to_pid (int num)
 443 {
 444   struct thread_info *thread = find_thread_id (num);
 445
 446   if (thread)
 447     return thread->ptid;
 448   else
 449     return pid_to_ptid (-1);
 450 }
 451
 452 int
 453 in_thread_list (ptid_t ptid)
 454 {
 455   struct thread_info *tp;
 456
 457   for (tp = thread_list; tp; tp = tp->next)
 458     if (ptid_equal (tp->ptid, ptid))
 459       return 1;
 460
 461   return 0;                     /* Never heard of 'im.  */
 462 }
 463
 464 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 465    return the first thread in the list.  */
 466
 467 struct thread_info *
 468 first_thread_of_process (int pid)
 469 {
 470   struct thread_info *tp, *ret = NULL;
 471
 472   for (tp = thread_list; tp; tp = tp->next)
 473     if (pid == -1 || ptid_get_pid (tp->ptid) == pid)
 474       if (ret == NULL || tp->num < ret->num)
 475         ret = tp;
 476
 477   return ret;
 478 }
 479
 480 struct thread_info *
 481 any_thread_of_process (int pid)
 482 {
 483   struct thread_info *tp;
 484
 485   gdb_assert (pid != 0);
 486
 487   /* Prefer the current thread.  */
 488   if (ptid_get_pid (inferior_ptid) == pid)
 489     return inferior_thread ();
 490
 491   ALL_NON_EXITED_THREADS (tp)
 492     if (ptid_get_pid (tp->ptid) == pid)
 493       return tp;
 494
 495   return NULL;
 496 }
 497
 498 struct thread_info *
 499 any_live_thread_of_process (int pid)
 500 {
 501   struct thread_info *curr_tp = NULL;
 502   struct thread_info *tp;
 503   struct thread_info *tp_executing = NULL;
 504
 505   gdb_assert (pid != 0);
 506
 507   /* Prefer the current thread if it's not executing.  */
 508   if (ptid_get_pid (inferior_ptid) == pid)
 509     {
 510       /* If the current thread is dead, forget it.  If it's not
 511          executing, use it.  Otherwise, still choose it (below), but
 512          only if no other non-executing thread is found.  */
 513       curr_tp = inferior_thread ();
 514       if (curr_tp->state == THREAD_EXITED)
 515         curr_tp = NULL;
 516       else if (!curr_tp->executing)
 517         return curr_tp;
 518     }
 519
 520   ALL_NON_EXITED_THREADS (tp)
 521     if (ptid_get_pid (tp->ptid) == pid)
 522       {
 523         if (!tp->executing)
 524           return tp;
 525
 526         tp_executing = tp;
 527       }
 528
 529   /* If both the current thread and all live threads are executing,
 530      prefer the current thread.  */
 531   if (curr_tp != NULL)
 532     return curr_tp;
 533
 534   /* Otherwise, just return an executing thread, if any.  */
 535   return tp_executing;
 536 }
 537
 538 /* Print a list of thread ids currently known, and the total number of
 539    threads.  To be used from within catch_errors.  */
 540 static int
 541 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 542 {
 543   struct thread_info *tp;
 544   int num = 0;
 545   struct cleanup *cleanup_chain;
 546   int current_thread = -1;
 547
 548   update_thread_list ();
 549
 550   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 551
 552   for (tp = thread_list; tp; tp = tp->next)
 553     {
 554       if (tp->state == THREAD_EXITED)
 555         continue;
 556
 557       if (ptid_equal (tp->ptid, inferior_ptid))
 558         current_thread = tp->num;
 559
 560       num++;
 561       ui_out_field_int (uiout, "thread-id", tp->num);
 562     }
 563
 564   do_cleanups (cleanup_chain);
 565
 566   if (current_thread != -1)
 567     ui_out_field_int (uiout, "current-thread-id", current_thread);
 568   ui_out_field_int (uiout, "number-of-threads", num);
 569   return GDB_RC_OK;
 570 }
 571
 572 /* Official gdblib interface function to get a list of thread ids and
 573    the total number.  */
 574 enum gdb_rc
 575 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 576 {
 577   if (catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 578                                  error_message, RETURN_MASK_ALL) < 0)
 579     return GDB_RC_FAIL;
 580   return GDB_RC_OK;
 581 }
 582
 583 /* Return true if TP is an active thread.  */
 584 static int
 585 thread_alive (struct thread_info *tp)
 586 {
 587   if (tp->state == THREAD_EXITED)
 588     return 0;
 589   if (!target_thread_alive (tp->ptid))
 590     return 0;
 591   return 1;
 592 }
 593
 594 static void
 595 prune_threads (void)
 596 {
 597   struct thread_info *tp, *next;
 598
 599   for (tp = thread_list; tp; tp = next)
 600     {
 601       next = tp->next;
 602       if (!thread_alive (tp))
 603         delete_thread (tp->ptid);
 604     }
 605 }
 606
 607 void
 608 thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid)
 609 {
 610   struct inferior *inf;
 611   struct thread_info *tp;
 612
 613   /* It can happen that what we knew as the target inferior id
 614      changes.  E.g, target remote may only discover the remote process
 615      pid after adding the inferior to GDB's list.  */
 616   inf = find_inferior_pid (ptid_get_pid (old_ptid));
 617   inf->pid = ptid_get_pid (new_ptid);
 618
 619   tp = find_thread_ptid (old_ptid);
 620   tp->ptid = new_ptid;
 621
 622   observer_notify_thread_ptid_changed (old_ptid, new_ptid);
 623 }
 624
 625 void
 626 set_running (ptid_t ptid, int running)
 627 {
 628   struct thread_info *tp;
 629   int all = ptid_equal (ptid, minus_one_ptid);
 630
 631   /* We try not to notify the observer if no thread has actually changed
 632      the running state -- merely to reduce the number of messages to
 633      frontend.  Frontend is supposed to handle multiple *running just fine.  */
 634   if (all || ptid_is_pid (ptid))
 635     {
 636       int any_started = 0;
 637
 638       for (tp = thread_list; tp; tp = tp->next)
 639         if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
 640           {
 641             if (tp->state == THREAD_EXITED)
 642               continue;
 643             if (running && tp->state == THREAD_STOPPED)
 644               any_started = 1;
 645             tp->state = running ? THREAD_RUNNING : THREAD_STOPPED;
 646           }
 647       if (any_started)
 648         observer_notify_target_resumed (ptid);
 649     }
 650   else
 651     {
 652       int started = 0;
 653
 654       tp = find_thread_ptid (ptid);
 655       gdb_assert (tp);
 656       gdb_assert (tp->state != THREAD_EXITED);
 657       if (running && tp->state == THREAD_STOPPED)
 658         started = 1;
 659       tp->state = running ? THREAD_RUNNING : THREAD_STOPPED;
 660       if (started)
 661         observer_notify_target_resumed (ptid);
 662     }
 663 }
 664
 665 static int
 666 is_thread_state (ptid_t ptid, enum thread_state state)
 667 {
 668   struct thread_info *tp;
 669
 670   tp = find_thread_ptid (ptid);
 671   gdb_assert (tp);
 672   return tp->state == state;
 673 }
 674
 675 int
 676 is_stopped (ptid_t ptid)
 677 {
 678   return is_thread_state (ptid, THREAD_STOPPED);
 679 }
 680
 681 int
 682 is_exited (ptid_t ptid)
 683 {
 684   return is_thread_state (ptid, THREAD_EXITED);
 685 }
 686
 687 int
 688 is_running (ptid_t ptid)
 689 {
 690   return is_thread_state (ptid, THREAD_RUNNING);
 691 }
 692
 693 int
 694 is_executing (ptid_t ptid)
 695 {
 696   struct thread_info *tp;
 697
 698   tp = find_thread_ptid (ptid);
 699   gdb_assert (tp);
 700   return tp->executing;
 701 }
 702
 703 void
 704 set_executing (ptid_t ptid, int executing)
 705 {
 706   struct thread_info *tp;
 707   int all = ptid_equal (ptid, minus_one_ptid);
 708
 709   if (all || ptid_is_pid (ptid))
 710     {
 711       for (tp = thread_list; tp; tp = tp->next)
 712         if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
 713           tp->executing = executing;
 714     }
 715   else
 716     {
 717       tp = find_thread_ptid (ptid);
 718       gdb_assert (tp);
 719       tp->executing = executing;
 720     }
 721
 722   /* It only takes one running thread to spawn more threads.*/
 723   if (executing)
 724     threads_executing = 1;
 725   /* Only clear the flag if the caller is telling us everything is
 726      stopped.  */
 727   else if (ptid_equal (minus_one_ptid, ptid))
 728     threads_executing = 0;
 729 }
 730
 731 /* See gdbthread.h.  */
 732
 733 int
 734 threads_are_executing (void)
 735 {
 736   return threads_executing;
 737 }
 738
 739 void
 740 set_stop_requested (ptid_t ptid, int stop)
 741 {
 742   struct thread_info *tp;
 743   int all = ptid_equal (ptid, minus_one_ptid);
 744
 745   if (all || ptid_is_pid (ptid))
 746     {
 747       for (tp = thread_list; tp; tp = tp->next)
 748         if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
 749           tp->stop_requested = stop;
 750     }
 751   else
 752     {
 753       tp = find_thread_ptid (ptid);
 754       gdb_assert (tp);
 755       tp->stop_requested = stop;
 756     }
 757
 758   /* Call the stop requested observer so other components of GDB can
 759      react to this request.  */
 760   if (stop)
 761     observer_notify_thread_stop_requested (ptid);
 762 }
 763
 764 void
 765 finish_thread_state (ptid_t ptid)
 766 {
 767   struct thread_info *tp;
 768   int all;
 769   int any_started = 0;
 770
 771   all = ptid_equal (ptid, minus_one_ptid);
 772
 773   if (all || ptid_is_pid (ptid))
 774     {
 775       for (tp = thread_list; tp; tp = tp->next)
 776         {
 777           if (tp->state == THREAD_EXITED)
 778             continue;
 779           if (all || ptid_get_pid (ptid) == ptid_get_pid (tp->ptid))
 780             {
 781               if (tp->executing && tp->state == THREAD_STOPPED)
 782                 any_started = 1;
 783               tp->state = tp->executing ? THREAD_RUNNING : THREAD_STOPPED;
 784             }
 785         }
 786     }
 787   else
 788     {
 789       tp = find_thread_ptid (ptid);
 790       gdb_assert (tp);
 791       if (tp->state != THREAD_EXITED)
 792         {
 793           if (tp->executing && tp->state == THREAD_STOPPED)
 794             any_started = 1;
 795           tp->state = tp->executing ? THREAD_RUNNING : THREAD_STOPPED;
 796         }
 797     }
 798
 799   if (any_started)
 800     observer_notify_target_resumed (ptid);
 801 }
 802
 803 void
 804 finish_thread_state_cleanup (void *arg)
 805 {
 806   ptid_t *ptid_p = arg;
 807
 808   gdb_assert (arg);
 809
 810   finish_thread_state (*ptid_p);
 811 }
 812
 813 int
 814 pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread)
 815 {
 816   return (pc >= thread->control.step_range_start
 817           && pc < thread->control.step_range_end);
 818 }
 819
 820 /* Prints the list of threads and their details on UIOUT.
 821    This is a version of 'info_threads_command' suitable for
 822    use from MI.
 823    If REQUESTED_THREAD is not -1, it's the GDB id of the thread
 824    that should be printed.  Otherwise, all threads are
 825    printed.
 826    If PID is not -1, only print threads from the process PID.
 827    Otherwise, threads from all attached PIDs are printed.
 828    If both REQUESTED_THREAD and PID are not -1, then the thread
 829    is printed if it belongs to the specified process.  Otherwise,
 830    an error is raised.  */
 831 void
 832 print_thread_info (struct ui_out *uiout, char *requested_threads, int pid)
 833 {
 834   struct thread_info *tp;
 835   ptid_t current_ptid;
 836   struct cleanup *old_chain;
 837   char *extra_info, *name, *target_id;
 838   int current_thread = -1;
 839
 840   update_thread_list ();
 841   current_ptid = inferior_ptid;
 842
 843   /* We'll be switching threads temporarily.  */
 844   old_chain = make_cleanup_restore_current_thread ();
 845
 846   /* For backward compatibility, we make a list for MI.  A table is
 847      preferable for the CLI, though, because it shows table
 848      headers.  */
 849   if (ui_out_is_mi_like_p (uiout))
 850     make_cleanup_ui_out_list_begin_end (uiout, "threads");
 851   else
 852     {
 853       int n_threads = 0;
 854
 855       for (tp = thread_list; tp; tp = tp->next)
 856         {
 857           if (!number_is_in_list (requested_threads, tp->num))
 858             continue;
 859
 860           if (pid != -1 && ptid_get_pid (tp->ptid) != pid)
 861             continue;
 862
 863           if (tp->state == THREAD_EXITED)
 864             continue;
 865
 866           ++n_threads;
 867         }
 868
 869       if (n_threads == 0)
 870         {
 871           if (requested_threads == NULL || *requested_threads == '\0')
 872             ui_out_message (uiout, 0, _("No threads.\n"));
 873           else
 874             ui_out_message (uiout, 0, _("No threads match '%s'.\n"),
 875                             requested_threads);
 876           do_cleanups (old_chain);
 877           return;
 878         }
 879
 880       make_cleanup_ui_out_table_begin_end (uiout, 4, n_threads, "threads");
 881
 882       ui_out_table_header (uiout, 1, ui_left, "current", "");
 883       ui_out_table_header (uiout, 4, ui_left, "id", "Id");
 884       ui_out_table_header (uiout, 17, ui_left, "target-id", "Target Id");
 885       ui_out_table_header (uiout, 1, ui_left, "frame", "Frame");
 886       ui_out_table_body (uiout);
 887     }
 888
 889   for (tp = thread_list; tp; tp = tp->next)
 890     {
 891       struct cleanup *chain2;
 892       int core;
 893
 894       if (!number_is_in_list (requested_threads, tp->num))
 895         continue;
 896
 897       if (pid != -1 && ptid_get_pid (tp->ptid) != pid)
 898         {
 899           if (requested_threads != NULL && *requested_threads != '\0')
 900             error (_("Requested thread not found in requested process"));
 901           continue;
 902         }
 903
 904       if (ptid_equal (tp->ptid, current_ptid))
 905         current_thread = tp->num;
 906
 907       if (tp->state == THREAD_EXITED)
 908         continue;
 909
 910       chain2 = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 911
 912       if (ui_out_is_mi_like_p (uiout))
 913         {
 914           /* Compatibility.  */
 915           if (ptid_equal (tp->ptid, current_ptid))
 916             ui_out_text (uiout, "* ");
 917           else
 918             ui_out_text (uiout, "  ");
 919         }
 920       else
 921         {
 922           if (ptid_equal (tp->ptid, current_ptid))
 923             ui_out_field_string (uiout, "current", "*");
 924           else
 925             ui_out_field_skip (uiout, "current");
 926         }
 927
 928       ui_out_field_int (uiout, "id", tp->num);
 929
 930       /* For the CLI, we stuff everything into the target-id field.
 931          This is a gross hack to make the output come out looking
 932          correct.  The underlying problem here is that ui-out has no
 933          way to specify that a field's space allocation should be
 934          shared by several fields.  For MI, we do the right thing
 935          instead.  */
 936
 937       target_id = target_pid_to_str (tp->ptid);
 938       extra_info = target_extra_thread_info (tp);
 939       name = tp->name ? tp->name : target_thread_name (tp);
 940
 941       if (ui_out_is_mi_like_p (uiout))
 942         {
 943           ui_out_field_string (uiout, "target-id", target_id);
 944           if (extra_info)
 945             ui_out_field_string (uiout, "details", extra_info);
 946           if (name)
 947             ui_out_field_string (uiout, "name", name);
 948         }
 949       else
 950         {
 951           struct cleanup *str_cleanup;
 952           char *contents;
 953
 954           if (extra_info && name)
 955             contents = xstrprintf ("%s \"%s\" (%s)", target_id,
 956                                    name, extra_info);
 957           else if (extra_info)
 958             contents = xstrprintf ("%s (%s)", target_id, extra_info);
 959           else if (name)
 960             contents = xstrprintf ("%s \"%s\"", target_id, name);
 961           else
 962             contents = xstrdup (target_id);
 963           str_cleanup = make_cleanup (xfree, contents);
 964
 965           ui_out_field_string (uiout, "target-id", contents);
 966           do_cleanups (str_cleanup);
 967         }
 968
 969       if (tp->state == THREAD_RUNNING)
 970         ui_out_text (uiout, "(running)\n");
 971       else
 972         {
 973           /* The switch below puts us at the top of the stack (leaf
 974              frame).  */
 975           switch_to_thread (tp->ptid);
 976           print_stack_frame (get_selected_frame (NULL),
 977                              /* For MI output, print frame level.  */
 978                              ui_out_is_mi_like_p (uiout),
 979                              LOCATION, 0);
 980         }
 981
 982       if (ui_out_is_mi_like_p (uiout))
 983         {
 984           char *state = "stopped";
 985
 986           if (tp->state == THREAD_RUNNING)
 987             state = "running";
 988           ui_out_field_string (uiout, "state", state);
 989         }
 990
 991       core = target_core_of_thread (tp->ptid);
 992       if (ui_out_is_mi_like_p (uiout) && core != -1)
 993         ui_out_field_int (uiout, "core", core);
 994
 995       do_cleanups (chain2);
 996     }
 997
 998   /* Restores the current thread and the frame selected before
 999      the "info threads" command.  */
1000   do_cleanups (old_chain);
1001
1002   if (pid == -1 && requested_threads == NULL)
1003     {
1004       gdb_assert (current_thread != -1
1005                   || !thread_list
1006                   || ptid_equal (inferior_ptid, null_ptid));
1007       if (current_thread != -1 && ui_out_is_mi_like_p (uiout))
1008         ui_out_field_int (uiout, "current-thread-id", current_thread);
1009
1010       if (current_thread != -1 && is_exited (current_ptid))
1011         ui_out_message (uiout, 0, "\n\
1012 The current thread <Thread ID %d> has terminated.  See `help thread'.\n",
1013                         current_thread);
1014       else if (thread_list
1015                && current_thread == -1
1016                && ptid_equal (current_ptid, null_ptid))
1017         ui_out_message (uiout, 0, "\n\
1018 No selected thread.  See `help thread'.\n");
1019     }
1020 }
1021
1022 /* Print information about currently known threads
1023
1024    Optional ARG is a thread id, or list of thread ids.
1025
1026    Note: this has the drawback that it _really_ switches
1027          threads, which frees the frame cache.  A no-side
1028          effects info-threads command would be nicer.  */
1029
1030 static void
1031 info_threads_command (char *arg, int from_tty)
1032 {
1033   print_thread_info (current_uiout, arg, -1);
1034 }
1035
1036 /* Switch from one thread to another.  */
1037
1038 void
1039 switch_to_thread (ptid_t ptid)
1040 {
1041   /* Switch the program space as well, if we can infer it from the now
1042      current thread.  Otherwise, it's up to the caller to select the
1043      space it wants.  */
1044   if (!ptid_equal (ptid, null_ptid))
1045     {
1046       struct inferior *inf;
1047
1048       inf = find_inferior_pid (ptid_get_pid (ptid));
1049       gdb_assert (inf != NULL);
1050       set_current_program_space (inf->pspace);
1051       set_current_inferior (inf);
1052     }
1053
1054   if (ptid_equal (ptid, inferior_ptid))
1055     return;
1056
1057   inferior_ptid = ptid;
1058   reinit_frame_cache ();
1059
1060   /* We don't check for is_stopped, because we're called at times
1061      while in the TARGET_RUNNING state, e.g., while handling an
1062      internal event.  */
1063   if (!ptid_equal (inferior_ptid, null_ptid)
1064       && !is_exited (ptid)
1065       && !is_executing (ptid))
1066     stop_pc = regcache_read_pc (get_thread_regcache (ptid));
1067   else
1068     stop_pc = ~(CORE_ADDR) 0;
1069 }
1070
1071 static void
1072 restore_current_thread (ptid_t ptid)
1073 {
1074   switch_to_thread (ptid);
1075 }
1076
1077 static void
1078 restore_selected_frame (struct frame_id a_frame_id, int frame_level)
1079 {
1080   struct frame_info *frame = NULL;
1081   int count;
1082
1083   /* This means there was no selected frame.  */
1084   if (frame_level == -1)
1085     {
1086       select_frame (NULL);
1087       return;
1088     }
1089
1090   gdb_assert (frame_level >= 0);
1091
1092   /* Restore by level first, check if the frame id is the same as
1093      expected.  If that fails, try restoring by frame id.  If that
1094      fails, nothing to do, just warn the user.  */
1095
1096   count = frame_level;
1097   frame = find_relative_frame (get_current_frame (), &count);
1098   if (count == 0
1099       && frame != NULL
1100       /* The frame ids must match - either both valid or both outer_frame_id.
1101          The latter case is not failsafe, but since it's highly unlikely
1102          the search by level finds the wrong frame, it's 99.9(9)% of
1103          the time (for all practical purposes) safe.  */
1104       && frame_id_eq (get_frame_id (frame), a_frame_id))
1105     {
1106       /* Cool, all is fine.  */
1107       select_frame (frame);
1108       return;
1109     }
1110
1111   frame = frame_find_by_id (a_frame_id);
1112   if (frame != NULL)
1113     {
1114       /* Cool, refound it.  */
1115       select_frame (frame);
1116       return;
1117     }
1118
1119   /* Nothing else to do, the frame layout really changed.  Select the
1120      innermost stack frame.  */
1121   select_frame (get_current_frame ());
1122
1123   /* Warn the user.  */
1124   if (frame_level > 0 && !ui_out_is_mi_like_p (current_uiout))
1125     {
1126       warning (_("Couldn't restore frame #%d in "
1127                  "current thread.  Bottom (innermost) frame selected:"),
1128                frame_level);
1129       /* For MI, we should probably have a notification about
1130          current frame change.  But this error is not very
1131          likely, so don't bother for now.  */
1132       print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC, 1);
1133     }
1134 }
1135
1136 struct current_thread_cleanup
1137 {
1138   ptid_t inferior_ptid;
1139   struct frame_id selected_frame_id;
1140   int selected_frame_level;
1141   int was_stopped;
1142   int inf_id;
1143   int was_removable;
1144 };
1145
1146 static void
1147 do_restore_current_thread_cleanup (void *arg)
1148 {
1149   struct thread_info *tp;
1150   struct current_thread_cleanup *old = arg;
1151
1152   tp = find_thread_ptid (old->inferior_ptid);
1153
1154   /* If the previously selected thread belonged to a process that has
1155      in the mean time been deleted (due to normal exit, detach, etc.),
1156      then don't revert back to it, but instead simply drop back to no
1157      thread selected.  */
1158   if (tp
1159       && find_inferior_pid (ptid_get_pid (tp->ptid)) != NULL)
1160     restore_current_thread (old->inferior_ptid);
1161   else
1162     {
1163       restore_current_thread (null_ptid);
1164       set_current_inferior (find_inferior_id (old->inf_id));
1165     }
1166
1167   /* The running state of the originally selected thread may have
1168      changed, so we have to recheck it here.  */
1169   if (!ptid_equal (inferior_ptid, null_ptid)
1170       && old->was_stopped
1171       && is_stopped (inferior_ptid)
1172       && target_has_registers
1173       && target_has_stack
1174       && target_has_memory)
1175     restore_selected_frame (old->selected_frame_id,
1176                             old->selected_frame_level);
1177 }
1178
1179 static void
1180 restore_current_thread_cleanup_dtor (void *arg)
1181 {
1182   struct current_thread_cleanup *old = arg;
1183   struct thread_info *tp;
1184   struct inferior *inf;
1185
1186   tp = find_thread_ptid (old->inferior_ptid);
1187   if (tp)
1188     tp->refcount--;
1189   inf = find_inferior_id (old->inf_id);
1190   if (inf != NULL)
1191     inf->removable = old->was_removable;
1192   xfree (old);
1193 }
1194
1195 /* Set the thread reference count.  */
1196
1197 static void
1198 set_thread_refcount (void *data)
1199 {
1200   int k;
1201   struct thread_array_cleanup *ta_cleanup = data;
1202
1203   for (k = 0; k != ta_cleanup->count; k++)
1204     ta_cleanup->tp_array[k]->refcount--;
1205 }
1206
1207 struct cleanup *
1208 make_cleanup_restore_current_thread (void)
1209 {
1210   struct thread_info *tp;
1211   struct frame_info *frame;
1212   struct current_thread_cleanup *old;
1213
1214   old = xmalloc (sizeof (struct current_thread_cleanup));
1215   old->inferior_ptid = inferior_ptid;
1216   old->inf_id = current_inferior ()->num;
1217   old->was_removable = current_inferior ()->removable;
1218
1219   if (!ptid_equal (inferior_ptid, null_ptid))
1220     {
1221       old->was_stopped = is_stopped (inferior_ptid);
1222       if (old->was_stopped
1223           && target_has_registers
1224           && target_has_stack
1225           && target_has_memory)
1226         {
1227           /* When processing internal events, there might not be a
1228              selected frame.  If we naively call get_selected_frame
1229              here, then we can end up reading debuginfo for the
1230              current frame, but we don't generally need the debuginfo
1231              at this point.  */
1232           frame = get_selected_frame_if_set ();
1233         }
1234       else
1235         frame = NULL;
1236
1237       old->selected_frame_id = get_frame_id (frame);
1238       old->selected_frame_level = frame_relative_level (frame);
1239
1240       tp = find_thread_ptid (inferior_ptid);
1241       if (tp)
1242         tp->refcount++;
1243     }
1244
1245   current_inferior ()->removable = 0;
1246
1247   return make_cleanup_dtor (do_restore_current_thread_cleanup, old,
1248                             restore_current_thread_cleanup_dtor);
1249 }
1250
1251 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
1252    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
1253    of two numbers seperated by a hyphen.  Examples:
1254
1255    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
1256    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
1257    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads.  */
1258
1259 static void
1260 thread_apply_all_command (char *cmd, int from_tty)
1261 {
1262   struct cleanup *old_chain;
1263   char *saved_cmd;
1264   int tc;
1265   struct thread_array_cleanup ta_cleanup;
1266
1267   if (cmd == NULL || *cmd == '\000')
1268     error (_("Please specify a command following the thread ID list"));
1269
1270   update_thread_list ();
1271
1272   old_chain = make_cleanup_restore_current_thread ();
1273
1274   /* Save a copy of the command in case it is clobbered by
1275      execute_command.  */
1276   saved_cmd = xstrdup (cmd);
1277   make_cleanup (xfree, saved_cmd);
1278   tc = thread_count ();
1279
1280   if (tc)
1281     {
1282       struct thread_info **tp_array;
1283       struct thread_info *tp;
1284       int i = 0, k;
1285
1286       /* Save a copy of the thread_list in case we execute detach
1287          command.  */
1288       tp_array = xmalloc (sizeof (struct thread_info *) * tc);
1289       make_cleanup (xfree, tp_array);
1290       ta_cleanup.tp_array = tp_array;
1291       ta_cleanup.count = tc;
1292
1293       ALL_NON_EXITED_THREADS (tp)
1294         {
1295           tp_array[i] = tp;
1296           tp->refcount++;
1297           i++;
1298         }
1299
1300       make_cleanup (set_thread_refcount, &ta_cleanup);
1301
1302       for (k = 0; k != i; k++)
1303         if (thread_alive (tp_array[k]))
1304           {
1305             switch_to_thread (tp_array[k]->ptid);
1306             printf_filtered (_("\nThread %d (%s):\n"),
1307                              tp_array[k]->num,
1308                              target_pid_to_str (inferior_ptid));
1309             execute_command (cmd, from_tty);
1310
1311             /* Restore exact command used previously.  */
1312             strcpy (cmd, saved_cmd);
1313           }
1314     }
1315
1316   do_cleanups (old_chain);
1317 }
1318
1319 static void
1320 thread_apply_command (char *tidlist, int from_tty)
1321 {
1322   char *cmd;
1323   struct cleanup *old_chain;
1324   char *saved_cmd;
1325   struct get_number_or_range_state state;
1326
1327   if (tidlist == NULL || *tidlist == '\000')
1328     error (_("Please specify a thread ID list"));
1329
1330   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
1331
1332   if (*cmd == '\000')
1333     error (_("Please specify a command following the thread ID list"));
1334
1335   /* Save a copy of the command in case it is clobbered by
1336      execute_command.  */
1337   saved_cmd = xstrdup (cmd);
1338   old_chain = make_cleanup (xfree, saved_cmd);
1339
1340   init_number_or_range (&state, tidlist);
1341   while (!state.finished && state.string < cmd)
1342     {
1343       struct thread_info *tp;
1344       int start;
1345
1346       start = get_number_or_range (&state);
1347
1348       make_cleanup_restore_current_thread ();
1349
1350       tp = find_thread_id (start);
1351
1352       if (!tp)
1353         warning (_("Unknown thread %d."), start);
1354       else if (!thread_alive (tp))
1355         warning (_("Thread %d has terminated."), start);
1356       else
1357         {
1358           switch_to_thread (tp->ptid);
1359
1360           printf_filtered (_("\nThread %d (%s):\n"), tp->num,
1361                            target_pid_to_str (inferior_ptid));
1362           execute_command (cmd, from_tty);
1363
1364           /* Restore exact command used previously.  */
1365           strcpy (cmd, saved_cmd);
1366         }
1367     }
1368
1369   do_cleanups (old_chain);
1370 }
1371
1372 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
1373    if prefix of arg is `apply'.  */
1374
1375 static void
1376 thread_command (char *tidstr, int from_tty)
1377 {
1378   if (!tidstr)
1379     {
1380       if (ptid_equal (inferior_ptid, null_ptid))
1381         error (_("No thread selected"));
1382
1383       if (target_has_stack)
1384         {
1385           if (is_exited (inferior_ptid))
1386             printf_filtered (_("[Current thread is %d (%s) (exited)]\n"),
1387                              pid_to_thread_id (inferior_ptid),
1388                              target_pid_to_str (inferior_ptid));
1389           else
1390             printf_filtered (_("[Current thread is %d (%s)]\n"),
1391                              pid_to_thread_id (inferior_ptid),
1392                              target_pid_to_str (inferior_ptid));
1393         }
1394       else
1395         error (_("No stack."));
1396       return;
1397     }
1398
1399   gdb_thread_select (current_uiout, tidstr, NULL);
1400 }
1401
1402 /* Implementation of `thread name'.  */
1403
1404 static void
1405 thread_name_command (char *arg, int from_tty)
1406 {
1407   struct thread_info *info;
1408
1409   if (ptid_equal (inferior_ptid, null_ptid))
1410     error (_("No thread selected"));
1411
1412   arg = skip_spaces (arg);
1413
1414   info = inferior_thread ();
1415   xfree (info->name);
1416   info->name = arg ? xstrdup (arg) : NULL;
1417 }
1418
1419 /* Find thread ids with a name, target pid, or extra info matching ARG.  */
1420
1421 static void
1422 thread_find_command (char *arg, int from_tty)
1423 {
1424   struct thread_info *tp;
1425   char *tmp;
1426   unsigned long match = 0;
1427
1428   if (arg == NULL || *arg == '\0')
1429     error (_("Command requires an argument."));
1430
1431   tmp = re_comp (arg);
1432   if (tmp != 0)
1433     error (_("Invalid regexp (%s): %s"), tmp, arg);
1434
1435   update_thread_list ();
1436   for (tp = thread_list; tp; tp = tp->next)
1437     {
1438       if (tp->name != NULL && re_exec (tp->name))
1439         {
1440           printf_filtered (_("Thread %d has name '%s'\n"),
1441                            tp->num, tp->name);
1442           match++;
1443         }
1444
1445       tmp = target_thread_name (tp);
1446       if (tmp != NULL && re_exec (tmp))
1447         {
1448           printf_filtered (_("Thread %d has target name '%s'\n"),
1449                            tp->num, tmp);
1450           match++;
1451         }
1452
1453       tmp = target_pid_to_str (tp->ptid);
1454       if (tmp != NULL && re_exec (tmp))
1455         {
1456           printf_filtered (_("Thread %d has target id '%s'\n"),
1457                            tp->num, tmp);
1458           match++;
1459         }
1460
1461       tmp = target_extra_thread_info (tp);
1462       if (tmp != NULL && re_exec (tmp))
1463         {
1464           printf_filtered (_("Thread %d has extra info '%s'\n"),
1465                            tp->num, tmp);
1466           match++;
1467         }
1468     }
1469   if (!match)
1470     printf_filtered (_("No threads match '%s'\n"), arg);
1471 }
1472
1473 /* Print notices when new threads are attached and detached.  */
1474 int print_thread_events = 1;
1475 static void
1476 show_print_thread_events (struct ui_file *file, int from_tty,
1477                           struct cmd_list_element *c, const char *value)
1478 {
1479   fprintf_filtered (file,
1480                     _("Printing of thread events is %s.\n"),
1481                     value);
1482 }
1483
1484 static int
1485 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
1486 {
1487   int num;
1488   struct thread_info *tp;
1489
1490   num = value_as_long (parse_and_eval (tidstr));
1491
1492   tp = find_thread_id (num);
1493
1494   if (!tp)
1495     error (_("Thread ID %d not known."), num);
1496
1497   if (!thread_alive (tp))
1498     error (_("Thread ID %d has terminated."), num);
1499
1500   switch_to_thread (tp->ptid);
1501
1502   annotate_thread_changed ();
1503
1504   ui_out_text (uiout, "[Switching to thread ");
1505   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
1506   ui_out_text (uiout, " (");
1507   ui_out_text (uiout, target_pid_to_str (inferior_ptid));
1508   ui_out_text (uiout, ")]");
1509
1510   /* Note that we can't reach this with an exited thread, due to the
1511      thread_alive check above.  */
1512   if (tp->state == THREAD_RUNNING)
1513     ui_out_text (uiout, "(running)\n");
1514   else
1515     {
1516       ui_out_text (uiout, "\n");
1517       print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC, 1);
1518     }
1519
1520   /* Since the current thread may have changed, see if there is any
1521      exited thread we can now delete.  */
1522   prune_threads ();
1523
1524   return GDB_RC_OK;
1525 }
1526
1527 enum gdb_rc
1528 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
1529 {
1530   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
1531                                  error_message, RETURN_MASK_ALL) < 0)
1532     return GDB_RC_FAIL;
1533   return GDB_RC_OK;
1534 }
1535
1536 /* Update the 'threads_executing' global based on the threads we know
1537    about right now.  */
1538
1539 static void
1540 update_threads_executing (void)
1541 {
1542   struct thread_info *tp;
1543
1544   threads_executing = 0;
1545   ALL_NON_EXITED_THREADS (tp)
1546     {
1547       if (tp->executing)
1548         {
1549           threads_executing = 1;
1550           break;
1551         }
1552     }
1553 }
1554
1555 void
1556 update_thread_list (void)
1557 {
1558   prune_threads ();
1559   target_find_new_threads ();
1560   update_threads_executing ();
1561 }
1562
1563 /* Return a new value for the selected thread's id.  Return a value of 0 if
1564    no thread is selected, or no threads exist.  */
1565
1566 static struct value *
1567 thread_id_make_value (struct gdbarch *gdbarch, struct internalvar *var,
1568                       void *ignore)
1569 {
1570   struct thread_info *tp = find_thread_ptid (inferior_ptid);
1571
1572   return value_from_longest (builtin_type (gdbarch)->builtin_int,
1573                              (tp ? tp->num : 0));
1574 }
1575
1576 /* Commands with a prefix of `thread'.  */
1577 struct cmd_list_element *thread_cmd_list = NULL;
1578
1579 /* Implementation of `thread' variable.  */
1580
1581 static const struct internalvar_funcs thread_funcs =
1582 {
1583   thread_id_make_value,
1584   NULL,
1585   NULL
1586 };
1587
1588 void
1589 _initialize_thread (void)
1590 {
1591   static struct cmd_list_element *thread_apply_list = NULL;
1592
1593   add_info ("threads", info_threads_command,
1594             _("Display currently known threads.\n\
1595 Usage: info threads [ID]...\n\
1596 Optional arguments are thread IDs with spaces between.\n\
1597 If no arguments, all threads are displayed."));
1598
1599   add_prefix_cmd ("thread", class_run, thread_command, _("\
1600 Use this command to switch between threads.\n\
1601 The new thread ID must be currently known."),
1602                   &thread_cmd_list, "thread ", 1, &cmdlist);
1603
1604   add_prefix_cmd ("apply", class_run, thread_apply_command,
1605                   _("Apply a command to a list of threads."),
1606                   &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
1607
1608   add_cmd ("all", class_run, thread_apply_all_command,
1609            _("Apply a command to all threads."), &thread_apply_list);
1610
1611   add_cmd ("name", class_run, thread_name_command,
1612            _("Set the current thread's name.\n\
1613 Usage: thread name [NAME]\n\
1614 If NAME is not given, then any existing name is removed."), &thread_cmd_list);
1615
1616   add_cmd ("find", class_run, thread_find_command, _("\
1617 Find threads that match a regular expression.\n\
1618 Usage: thread find REGEXP\n\
1619 Will display thread ids whose name, target ID, or extra info matches REGEXP."),
1620            &thread_cmd_list);
1621
1622   if (!xdb_commands)
1623     add_com_alias ("t", "thread", class_run, 1);
1624
1625   add_setshow_boolean_cmd ("thread-events", no_class,
1626          &print_thread_events, _("\
1627 Set printing of thread events (such as thread start and exit)."), _("\
1628 Show printing of thread events (such as thread start and exit)."), NULL,
1629          NULL,
1630          show_print_thread_events,
1631          &setprintlist, &showprintlist);
1632
1633   create_internalvar_type_lazy ("_thread", &thread_funcs, NULL);
1634 }