gdb/thread.c

   1 /* Multi-process/thread control for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986, 1987, 1988, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   4    2000, 2001, 2002, 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
   5
   6    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  22
  23 #include "defs.h"
  24 #include "symtab.h"
  25 #include "frame.h"
  26 #include "inferior.h"
  27 #include "environ.h"
  28 #include "value.h"
  29 #include "target.h"
  30 #include "gdbthread.h"
  31 #include "exceptions.h"
  32 #include "command.h"
  33 #include "gdbcmd.h"
  34 #include "regcache.h"
  35 #include "gdb.h"
  36 #include "gdb_string.h"
  37
  38 #include <ctype.h>
  39 #include <sys/types.h>
  40 #include <signal.h>
  41 #include "ui-out.h"
  42 #include "observer.h"
  43 #include "annotate.h"
  44 #include "cli/cli-decode.h"
  45
  46 /* Definition of struct thread_info exported to gdbthread.h */
  47
  48 /* Prototypes for exported functions. */
  49
  50 void _initialize_thread (void);
  51
  52 /* Prototypes for local functions. */
  53
  54 static struct thread_info *thread_list = NULL;
  55 static int highest_thread_num;
  56
  57 static void thread_command (char *tidstr, int from_tty);
  58 static void thread_apply_all_command (char *, int);
  59 static int thread_alive (struct thread_info *);
  60 static void info_threads_command (char *, int);
  61 static void thread_apply_command (char *, int);
  62 static void restore_current_thread (ptid_t);
  63 static void prune_threads (void);
  64
  65 /* Frontend view of the thread state.  Possible extensions: stepping,
  66    finishing, until(ling),...  */
  67 enum thread_state
  68 {
  69   THREAD_STOPPED,
  70   THREAD_RUNNING,
  71   THREAD_EXITED,
  72 };
  73
  74 extern struct thread_info*
  75 inferior_thread (void)
  76 {
  77   struct thread_info *tp = find_thread_pid (inferior_ptid);
  78   gdb_assert (tp);
  79   return tp;
  80 }
  81
  82 void
  83 delete_step_resume_breakpoint (struct thread_info *tp)
  84 {
  85   if (tp && tp->step_resume_breakpoint)
  86     {
  87       delete_breakpoint (tp->step_resume_breakpoint);
  88       tp->step_resume_breakpoint = NULL;
  89     }
  90 }
  91
  92 static void
  93 clear_thread_inferior_resources (struct thread_info *tp)
  94 {
  95   /* NOTE: this will take care of any left-over step_resume breakpoints,
  96      but not any user-specified thread-specific breakpoints.  We can not
  97      delete the breakpoint straight-off, because the inferior might not
  98      be stopped at the moment.  */
  99   if (tp->step_resume_breakpoint)
 100     {
 101       tp->step_resume_breakpoint->disposition = disp_del_at_next_stop;
 102       tp->step_resume_breakpoint = NULL;
 103     }
 104
 105   bpstat_clear (&tp->stop_bpstat);
 106
 107   discard_all_intermediate_continuations_thread (tp);
 108   discard_all_continuations_thread (tp);
 109 }
 110
 111 static void
 112 free_thread (struct thread_info *tp)
 113 {
 114   clear_thread_inferior_resources (tp);
 115
 116   /* FIXME: do I ever need to call the back-end to give it a
 117      chance at this private data before deleting the thread?  */
 118   if (tp->private)
 119     xfree (tp->private);
 120
 121   xfree (tp);
 122 }
 123
 124 void
 125 init_thread_list (void)
 126 {
 127   struct thread_info *tp, *tpnext;
 128
 129   highest_thread_num = 0;
 130
 131   if (!thread_list)
 132     return;
 133
 134   for (tp = thread_list; tp; tp = tpnext)
 135     {
 136       tpnext = tp->next;
 137       free_thread (tp);
 138     }
 139
 140   thread_list = NULL;
 141 }
 142
 143 struct thread_info *
 144 add_thread_silent (ptid_t ptid)
 145 {
 146   struct thread_info *tp;
 147
 148   tp = find_thread_pid (ptid);
 149   if (tp)
 150     /* Found an old thread with the same id.  It has to be dead,
 151        otherwise we wouldn't be adding a new thread with the same id.
 152        The OS is reusing this id --- delete it, and recreate a new
 153        one.  */
 154     {
 155       /* In addition to deleting the thread, if this is the current
 156          thread, then we need to take care that delete_thread doesn't
 157          really delete the thread if it is inferior_ptid.  Create a
 158          new template thread in the list with an invalid ptid, switch
 159          to it, delete the original thread, reset the new thread's
 160          ptid, and switch to it.  */
 161
 162       if (ptid_equal (inferior_ptid, ptid))
 163         {
 164           tp = xmalloc (sizeof (*tp));
 165           memset (tp, 0, sizeof (*tp));
 166           tp->ptid = minus_one_ptid;
 167           tp->num = ++highest_thread_num;
 168           tp->next = thread_list;
 169           thread_list = tp;
 170
 171           /* Make switch_to_thread not read from the thread.  */
 172           tp->state_ = THREAD_EXITED;
 173           switch_to_thread (minus_one_ptid);
 174
 175           /* Now we can delete it.  */
 176           delete_thread (ptid);
 177
 178           /* Now reset its ptid, and reswitch inferior_ptid to it.  */
 179           tp->ptid = ptid;
 180           tp->state_ = THREAD_STOPPED;
 181           switch_to_thread (ptid);
 182
 183           observer_notify_new_thread (tp);
 184
 185           /* All done.  */
 186           return tp;
 187         }
 188       else
 189         /* Just go ahead and delete it.  */
 190         delete_thread (ptid);
 191     }
 192
 193   tp = (struct thread_info *) xmalloc (sizeof (*tp));
 194   memset (tp, 0, sizeof (*tp));
 195   tp->ptid = ptid;
 196   tp->num = ++highest_thread_num;
 197   tp->next = thread_list;
 198   thread_list = tp;
 199
 200   observer_notify_new_thread (tp);
 201
 202   return tp;
 203 }
 204
 205 struct thread_info *
 206 add_thread_with_info (ptid_t ptid, struct private_thread_info *private)
 207 {
 208   struct thread_info *result = add_thread_silent (ptid);
 209
 210   result->private = private;
 211
 212   if (print_thread_events)
 213     printf_unfiltered (_("[New %s]\n"), target_pid_to_str (ptid));
 214
 215   annotate_new_thread ();
 216   return result;
 217 }
 218
 219 struct thread_info *
 220 add_thread (ptid_t ptid)
 221 {
 222   return add_thread_with_info (ptid, NULL);
 223 }
 224
 225 /* Delete thread PTID.  If SILENT, don't notify the observer of this
 226    exit.  */
 227 static void
 228 delete_thread_1 (ptid_t ptid, int silent)
 229 {
 230   struct thread_info *tp, *tpprev;
 231
 232   tpprev = NULL;
 233
 234   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 235     if (ptid_equal (tp->ptid, ptid))
 236       break;
 237
 238   if (!tp)
 239     return;
 240
 241   /* If this is the current thread, or there's code out there that
 242      relies on it existing (refcount > 0) we can't delete yet.  Mark
 243      it as exited, and notify it.  */
 244   if (tp->refcount > 0
 245       || ptid_equal (tp->ptid, inferior_ptid))
 246     {
 247       if (tp->state_ != THREAD_EXITED)
 248         {
 249           if (!silent)
 250             observer_notify_thread_exit (tp);
 251
 252           /* Tag it as exited.  */
 253           tp->state_ = THREAD_EXITED;
 254
 255           /* Clear breakpoints, etc. associated with this thread.  */
 256           clear_thread_inferior_resources (tp);
 257         }
 258
 259        /* Will be really deleted some other time.  */
 260        return;
 261      }
 262
 263   if (tpprev)
 264     tpprev->next = tp->next;
 265   else
 266     thread_list = tp->next;
 267
 268   /* Notify thread exit, but only if we haven't already.  */
 269   if (!silent && tp->state_ != THREAD_EXITED)
 270     observer_notify_thread_exit (tp);
 271
 272   free_thread (tp);
 273 }
 274
 275 /* Delete thread PTID and notify of thread exit.  If this is
 276    inferior_ptid, don't actually delete it, but tag it as exited and
 277    do the notification.  If PTID is the user selected thread, clear
 278    it.  */
 279 void
 280 delete_thread (ptid_t ptid)
 281 {
 282   delete_thread_1 (ptid, 0 /* not silent */);
 283 }
 284
 285 void
 286 delete_thread_silent (ptid_t ptid)
 287 {
 288   delete_thread_1 (ptid, 1 /* silent */);
 289 }
 290
 291 struct thread_info *
 292 find_thread_id (int num)
 293 {
 294   struct thread_info *tp;
 295
 296   for (tp = thread_list; tp; tp = tp->next)
 297     if (tp->num == num)
 298       return tp;
 299
 300   return NULL;
 301 }
 302
 303 /* Find a thread_info by matching PTID.  */
 304 struct thread_info *
 305 find_thread_pid (ptid_t ptid)
 306 {
 307   struct thread_info *tp;
 308
 309   for (tp = thread_list; tp; tp = tp->next)
 310     if (ptid_equal (tp->ptid, ptid))
 311       return tp;
 312
 313   return NULL;
 314 }
 315
 316 /*
 317  * Thread iterator function.
 318  *
 319  * Calls a callback function once for each thread, so long as
 320  * the callback function returns false.  If the callback function
 321  * returns true, the iteration will end and the current thread
 322  * will be returned.  This can be useful for implementing a
 323  * search for a thread with arbitrary attributes, or for applying
 324  * some operation to every thread.
 325  *
 326  * FIXME: some of the existing functionality, such as
 327  * "Thread apply all", might be rewritten using this functionality.
 328  */
 329
 330 struct thread_info *
 331 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 332                       void *data)
 333 {
 334   struct thread_info *tp, *next;
 335
 336   for (tp = thread_list; tp; tp = next)
 337     {
 338       next = tp->next;
 339       if ((*callback) (tp, data))
 340         return tp;
 341     }
 342
 343   return NULL;
 344 }
 345
 346 int
 347 thread_count (void)
 348 {
 349   int result = 0;
 350   struct thread_info *tp;
 351
 352   for (tp = thread_list; tp; tp = tp->next)
 353     ++result;
 354
 355   return result;
 356 }
 357
 358 int
 359 valid_thread_id (int num)
 360 {
 361   struct thread_info *tp;
 362
 363   for (tp = thread_list; tp; tp = tp->next)
 364     if (tp->num == num)
 365       return 1;
 366
 367   return 0;
 368 }
 369
 370 int
 371 pid_to_thread_id (ptid_t ptid)
 372 {
 373   struct thread_info *tp;
 374
 375   for (tp = thread_list; tp; tp = tp->next)
 376     if (ptid_equal (tp->ptid, ptid))
 377       return tp->num;
 378
 379   return 0;
 380 }
 381
 382 ptid_t
 383 thread_id_to_pid (int num)
 384 {
 385   struct thread_info *thread = find_thread_id (num);
 386   if (thread)
 387     return thread->ptid;
 388   else
 389     return pid_to_ptid (-1);
 390 }
 391
 392 int
 393 in_thread_list (ptid_t ptid)
 394 {
 395   struct thread_info *tp;
 396
 397   for (tp = thread_list; tp; tp = tp->next)
 398     if (ptid_equal (tp->ptid, ptid))
 399       return 1;
 400
 401   return 0;                     /* Never heard of 'im */
 402 }
 403
 404 /* Print a list of thread ids currently known, and the total number of
 405    threads. To be used from within catch_errors. */
 406 static int
 407 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 408 {
 409   struct thread_info *tp;
 410   int num = 0;
 411   struct cleanup *cleanup_chain;
 412
 413   prune_threads ();
 414   target_find_new_threads ();
 415
 416   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 417
 418   for (tp = thread_list; tp; tp = tp->next)
 419     {
 420       if (tp->state_ == THREAD_EXITED)
 421         continue;
 422       num++;
 423       ui_out_field_int (uiout, "thread-id", tp->num);
 424     }
 425
 426   do_cleanups (cleanup_chain);
 427   ui_out_field_int (uiout, "number-of-threads", num);
 428   return GDB_RC_OK;
 429 }
 430
 431 /* Official gdblib interface function to get a list of thread ids and
 432    the total number. */
 433 enum gdb_rc
 434 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 435 {
 436   if (catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 437                                  error_message, RETURN_MASK_ALL) < 0)
 438     return GDB_RC_FAIL;
 439   return GDB_RC_OK;
 440 }
 441
 442 /* Return true if TP is an active thread. */
 443 static int
 444 thread_alive (struct thread_info *tp)
 445 {
 446   if (tp->state_ == THREAD_EXITED)
 447     return 0;
 448   if (!target_thread_alive (tp->ptid))
 449     return 0;
 450   return 1;
 451 }
 452
 453 static void
 454 prune_threads (void)
 455 {
 456   struct thread_info *tp, *next;
 457
 458   for (tp = thread_list; tp; tp = next)
 459     {
 460       next = tp->next;
 461       if (!thread_alive (tp))
 462         delete_thread (tp->ptid);
 463     }
 464 }
 465
 466 void
 467 thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid)
 468 {
 469   struct inferior *inf;
 470   struct thread_info *tp;
 471
 472   /* It can happen that what we knew as the target inferior id
 473      changes.  E.g, target remote may only discover the remote process
 474      pid after adding the inferior to GDB's list.  */
 475   inf = find_inferior_pid (ptid_get_pid (old_ptid));
 476   inf->pid = ptid_get_pid (new_ptid);
 477
 478   tp = find_thread_pid (old_ptid);
 479   tp->ptid = new_ptid;
 480
 481   observer_notify_thread_ptid_changed (old_ptid, new_ptid);
 482 }
 483
 484 void
 485 set_running (ptid_t ptid, int running)
 486 {
 487   struct thread_info *tp;
 488
 489   /* We try not to notify the observer if no thread has actually changed
 490      the running state -- merely to reduce the number of messages to
 491      frontend.  Frontend is supposed to handle multiple *running just fine.  */
 492   if (PIDGET (ptid) == -1)
 493     {
 494       int any_started = 0;
 495       for (tp = thread_list; tp; tp = tp->next)
 496         {
 497           if (tp->state_ == THREAD_EXITED)
 498             continue;
 499           if (running && tp->state_ == THREAD_STOPPED)
 500             any_started = 1;
 501           tp->state_ = running ? THREAD_RUNNING : THREAD_STOPPED;
 502         }
 503       if (any_started && !suppress_resume_observer)
 504         observer_notify_target_resumed (ptid);
 505     }
 506   else
 507     {
 508       int started = 0;
 509       tp = find_thread_pid (ptid);
 510       gdb_assert (tp);
 511       gdb_assert (tp->state_ != THREAD_EXITED);
 512       if (running && tp->state_ == THREAD_STOPPED)
 513         started = 1;
 514       tp->state_ = running ? THREAD_RUNNING : THREAD_STOPPED;
 515       if (started && !suppress_resume_observer)
 516         observer_notify_target_resumed (ptid);
 517     }
 518 }
 519
 520 static int
 521 is_thread_state (ptid_t ptid, enum thread_state state)
 522 {
 523   struct thread_info *tp;
 524
 525   if (!target_has_execution)
 526     return 0;
 527
 528   tp = find_thread_pid (ptid);
 529   gdb_assert (tp);
 530   return tp->state_ == state;
 531 }
 532
 533 int
 534 is_stopped (ptid_t ptid)
 535 {
 536   /* Without execution, this property is always true.  */
 537   if (!target_has_execution)
 538     return 1;
 539
 540   return is_thread_state (ptid, THREAD_STOPPED);
 541 }
 542
 543 int
 544 is_exited (ptid_t ptid)
 545 {
 546   /* Without execution, this property is always false.  */
 547   if (!target_has_execution)
 548     return 0;
 549
 550   return is_thread_state (ptid, THREAD_EXITED);
 551 }
 552
 553 int
 554 is_running (ptid_t ptid)
 555 {
 556    /* Without execution, this property is always false.  */
 557   if (!target_has_execution)
 558     return 0;
 559
 560   return is_thread_state (ptid, THREAD_RUNNING);
 561 }
 562
 563 int
 564 any_running (void)
 565 {
 566   struct thread_info *tp;
 567
 568   if (!target_has_execution)
 569     return 0;
 570
 571   for (tp = thread_list; tp; tp = tp->next)
 572     if (tp->state_ == THREAD_RUNNING)
 573       return 1;
 574
 575   return 0;
 576 }
 577
 578 int
 579 is_executing (ptid_t ptid)
 580 {
 581   struct thread_info *tp;
 582
 583   if (!target_has_execution)
 584     return 0;
 585
 586   tp = find_thread_pid (ptid);
 587   gdb_assert (tp);
 588   return tp->executing_;
 589 }
 590
 591 void
 592 set_executing (ptid_t ptid, int executing)
 593 {
 594   struct thread_info *tp;
 595
 596   if (PIDGET (ptid) == -1)
 597     {
 598       for (tp = thread_list; tp; tp = tp->next)
 599         tp->executing_ = executing;
 600     }
 601   else
 602     {
 603       tp = find_thread_pid (ptid);
 604       gdb_assert (tp);
 605       tp->executing_ = executing;
 606     }
 607 }
 608
 609 void
 610 set_stop_requested (ptid_t ptid, int stop)
 611 {
 612   struct thread_info *tp;
 613   int all = ptid_equal (ptid, minus_one_ptid);
 614
 615   if (all || ptid_is_pid (ptid))
 616     {
 617       for (tp = thread_list; tp; tp = tp->next)
 618         if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
 619           tp->stop_requested = stop;
 620     }
 621   else
 622     {
 623       tp = find_thread_pid (ptid);
 624       gdb_assert (tp);
 625       tp->stop_requested = stop;
 626     }
 627
 628   /* Call the stop requested observer so other components of GDB can
 629      react to this request.  */
 630   if (stop)
 631     observer_notify_thread_stop_requested (ptid);
 632 }
 633
 634 /* Prints the list of threads and their details on UIOUT.
 635    This is a version of 'info_thread_command' suitable for
 636    use from MI.
 637    If REQUESTED_THREAD is not -1, it's the GDB id of the thread
 638    that should be printed.  Otherwise, all threads are
 639    printed.  */
 640 void
 641 print_thread_info (struct ui_out *uiout, int requested_thread)
 642 {
 643   struct thread_info *tp;
 644   ptid_t current_ptid;
 645   struct cleanup *old_chain;
 646   char *extra_info;
 647   int current_thread = -1;
 648
 649   prune_threads ();
 650   target_find_new_threads ();
 651   current_ptid = inferior_ptid;
 652
 653   /* We'll be switching threads temporarily.  */
 654   old_chain = make_cleanup_restore_current_thread ();
 655
 656   make_cleanup_ui_out_list_begin_end (uiout, "threads");
 657   for (tp = thread_list; tp; tp = tp->next)
 658     {
 659       struct cleanup *chain2;
 660
 661       if (requested_thread != -1 && tp->num != requested_thread)
 662         continue;
 663
 664       if (ptid_equal (tp->ptid, current_ptid))
 665         current_thread = tp->num;
 666
 667       if (tp->state_ == THREAD_EXITED)
 668         continue;
 669
 670       chain2 = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 671
 672       if (ptid_equal (tp->ptid, current_ptid))
 673         ui_out_text (uiout, "* ");
 674       else
 675         ui_out_text (uiout, "  ");
 676
 677       ui_out_field_int (uiout, "id", tp->num);
 678       ui_out_text (uiout, " ");
 679       ui_out_field_string (uiout, "target-id", target_tid_to_str (tp->ptid));
 680
 681       extra_info = target_extra_thread_info (tp);
 682       if (extra_info)
 683         {
 684           ui_out_text (uiout, " (");
 685           ui_out_field_string (uiout, "details", extra_info);
 686           ui_out_text (uiout, ")");
 687         }
 688       ui_out_text (uiout, "  ");
 689
 690       if (tp->state_ == THREAD_RUNNING)
 691         ui_out_text (uiout, "(running)\n");
 692       else
 693         {
 694           /* The switch below puts us at the top of the stack (leaf
 695              frame).  */
 696           switch_to_thread (tp->ptid);
 697           print_stack_frame (get_selected_frame (NULL),
 698                              /* For MI output, print frame level.  */
 699                              ui_out_is_mi_like_p (uiout),
 700                              LOCATION);
 701         }
 702
 703       if (ui_out_is_mi_like_p (uiout))
 704         {
 705           char *state = "stopped";
 706           if (tp->state_ == THREAD_RUNNING)
 707             state = "running";
 708           ui_out_field_string (uiout, "state", state);
 709         }
 710
 711       do_cleanups (chain2);
 712     }
 713
 714   /* Restores the current thread and the frame selected before
 715      the "info threads" command.  */
 716   do_cleanups (old_chain);
 717
 718   if (requested_thread == -1)
 719     {
 720       gdb_assert (current_thread != -1
 721                   || !thread_list);
 722       if (current_thread != -1 && ui_out_is_mi_like_p (uiout))
 723         ui_out_field_int (uiout, "current-thread-id", current_thread);
 724
 725       if (current_thread != -1 && is_exited (current_ptid))
 726         ui_out_message (uiout, 0, "\n\
 727 The current thread <Thread ID %d> has terminated.  See `help thread'.\n",
 728                         current_thread);
 729     }
 730 }
 731
 732
 733 /* Print information about currently known threads
 734
 735  * Note: this has the drawback that it _really_ switches
 736  *       threads, which frees the frame cache.  A no-side
 737  *       effects info-threads command would be nicer.
 738  */
 739
 740 static void
 741 info_threads_command (char *arg, int from_tty)
 742 {
 743   print_thread_info (uiout, -1);
 744 }
 745
 746 /* Switch from one thread to another. */
 747
 748 void
 749 switch_to_thread (ptid_t ptid)
 750 {
 751   if (ptid_equal (ptid, inferior_ptid))
 752     return;
 753
 754   inferior_ptid = ptid;
 755   reinit_frame_cache ();
 756   registers_changed ();
 757
 758   /* We don't check for is_stopped, because we're called at times
 759      while in the TARGET_RUNNING state, e.g., while handling an
 760      internal event.  */
 761   if (!is_exited (ptid) && !is_executing (ptid))
 762     stop_pc = read_pc ();
 763   else
 764     stop_pc = ~(CORE_ADDR) 0;
 765 }
 766
 767 static void
 768 restore_current_thread (ptid_t ptid)
 769 {
 770   switch_to_thread (ptid);
 771 }
 772
 773 static void
 774 restore_selected_frame (struct frame_id a_frame_id, int frame_level)
 775 {
 776   struct frame_info *frame = NULL;
 777   int count;
 778
 779   gdb_assert (frame_level >= 0);
 780
 781   /* Restore by level first, check if the frame id is the same as
 782      expected.  If that fails, try restoring by frame id.  If that
 783      fails, nothing to do, just warn the user.  */
 784
 785   count = frame_level;
 786   frame = find_relative_frame (get_current_frame (), &count);
 787   if (count == 0
 788       && frame != NULL
 789       /* Either the frame ids match, of they're both invalid.  The
 790          latter case is not failsafe, but since it's highly unlikely
 791          the search by level finds the wrong frame, it's 99.9(9)% of
 792          the time (for all practical purposes) safe.  */
 793       && (frame_id_eq (get_frame_id (frame), a_frame_id)
 794           /* Note: could be better to check every frame_id
 795              member for equality here.  */
 796           || (!frame_id_p (get_frame_id (frame))
 797               && !frame_id_p (a_frame_id))))
 798     {
 799       /* Cool, all is fine.  */
 800       select_frame (frame);
 801       return;
 802     }
 803
 804   frame = frame_find_by_id (a_frame_id);
 805   if (frame != NULL)
 806     {
 807       /* Cool, refound it.  */
 808       select_frame (frame);
 809       return;
 810     }
 811
 812   /* Nothing else to do, the frame layout really changed.  Select the
 813      innermost stack frame.  */
 814   select_frame (get_current_frame ());
 815
 816   /* Warn the user.  */
 817   if (!ui_out_is_mi_like_p (uiout))
 818     {
 819       warning (_("\
 820 Couldn't restore frame #%d in current thread, at reparsed frame #0\n"),
 821                frame_level);
 822       /* For MI, we should probably have a notification about
 823          current frame change.  But this error is not very
 824          likely, so don't bother for now.  */
 825       print_stack_frame (get_selected_frame (NULL), 1, SRC_LINE);
 826     }
 827 }
 828
 829 struct current_thread_cleanup
 830 {
 831   ptid_t inferior_ptid;
 832   struct frame_id selected_frame_id;
 833   int selected_frame_level;
 834   int was_stopped;
 835 };
 836
 837 static void
 838 do_restore_current_thread_cleanup (void *arg)
 839 {
 840   struct thread_info *tp;
 841   struct current_thread_cleanup *old = arg;
 842   restore_current_thread (old->inferior_ptid);
 843
 844   /* The running state of the originally selected thread may have
 845      changed, so we have to recheck it here.  */
 846   if (old->was_stopped
 847       && is_stopped (inferior_ptid)
 848       && target_has_registers
 849       && target_has_stack
 850       && target_has_memory)
 851     restore_selected_frame (old->selected_frame_id,
 852                             old->selected_frame_level);
 853 }
 854
 855 static void
 856 restore_current_thread_cleanup_dtor (void *arg)
 857 {
 858   struct current_thread_cleanup *old = arg;
 859   struct thread_info *tp;
 860   tp = find_thread_pid (old->inferior_ptid);
 861   if (tp)
 862     tp->refcount--;
 863   xfree (old);
 864 }
 865
 866 struct cleanup *
 867 make_cleanup_restore_current_thread (void)
 868 {
 869   struct thread_info *tp;
 870   struct frame_info *frame;
 871   struct current_thread_cleanup *old;
 872
 873   old = xmalloc (sizeof (struct current_thread_cleanup));
 874   old->inferior_ptid = inferior_ptid;
 875   old->was_stopped = is_stopped (inferior_ptid);
 876   if (old->was_stopped
 877       && target_has_registers
 878       && target_has_stack
 879       && target_has_memory)
 880     frame = get_selected_frame (NULL);
 881   else
 882     frame = NULL;
 883
 884   old->selected_frame_id = get_frame_id (frame);
 885   old->selected_frame_level = frame_relative_level (frame);
 886
 887   tp = find_thread_pid (inferior_ptid);
 888   if (tp)
 889     tp->refcount++;
 890
 891   return make_cleanup_dtor (do_restore_current_thread_cleanup, old,
 892                             restore_current_thread_cleanup_dtor);
 893 }
 894
 895 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 896    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 897    of two numbers seperated by a hyphen.  Examples:
 898
 899    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 900    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 901    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 902  */
 903
 904 static void
 905 thread_apply_all_command (char *cmd, int from_tty)
 906 {
 907   struct thread_info *tp;
 908   struct cleanup *old_chain;
 909   char *saved_cmd;
 910
 911   if (cmd == NULL || *cmd == '\000')
 912     error (_("Please specify a command following the thread ID list"));
 913
 914   prune_threads ();
 915   target_find_new_threads ();
 916
 917   old_chain = make_cleanup_restore_current_thread ();
 918
 919   /* Save a copy of the command in case it is clobbered by
 920      execute_command */
 921   saved_cmd = xstrdup (cmd);
 922   make_cleanup (xfree, saved_cmd);
 923   for (tp = thread_list; tp; tp = tp->next)
 924     if (thread_alive (tp))
 925       {
 926         switch_to_thread (tp->ptid);
 927
 928         printf_filtered (_("\nThread %d (%s):\n"),
 929                          tp->num, target_tid_to_str (inferior_ptid));
 930         execute_command (cmd, from_tty);
 931         strcpy (cmd, saved_cmd);        /* Restore exact command used previously */
 932       }
 933
 934   do_cleanups (old_chain);
 935 }
 936
 937 static void
 938 thread_apply_command (char *tidlist, int from_tty)
 939 {
 940   char *cmd;
 941   char *p;
 942   struct cleanup *old_chain;
 943   char *saved_cmd;
 944
 945   if (tidlist == NULL || *tidlist == '\000')
 946     error (_("Please specify a thread ID list"));
 947
 948   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 949
 950   if (*cmd == '\000')
 951     error (_("Please specify a command following the thread ID list"));
 952
 953   /* Save a copy of the command in case it is clobbered by
 954      execute_command */
 955   saved_cmd = xstrdup (cmd);
 956   old_chain = make_cleanup (xfree, saved_cmd);
 957   while (tidlist < cmd)
 958     {
 959       struct thread_info *tp;
 960       int start, end;
 961
 962       start = strtol (tidlist, &p, 10);
 963       if (p == tidlist)
 964         error (_("Error parsing %s"), tidlist);
 965       tidlist = p;
 966
 967       while (*tidlist == ' ' || *tidlist == '\t')
 968         tidlist++;
 969
 970       if (*tidlist == '-')      /* Got a range of IDs? */
 971         {
 972           tidlist++;            /* Skip the - */
 973           end = strtol (tidlist, &p, 10);
 974           if (p == tidlist)
 975             error (_("Error parsing %s"), tidlist);
 976           tidlist = p;
 977
 978           while (*tidlist == ' ' || *tidlist == '\t')
 979             tidlist++;
 980         }
 981       else
 982         end = start;
 983
 984       make_cleanup_restore_current_thread ();
 985
 986       for (; start <= end; start++)
 987         {
 988           tp = find_thread_id (start);
 989
 990           if (!tp)
 991             warning (_("Unknown thread %d."), start);
 992           else if (!thread_alive (tp))
 993             warning (_("Thread %d has terminated."), start);
 994           else
 995             {
 996               switch_to_thread (tp->ptid);
 997
 998               printf_filtered (_("\nThread %d (%s):\n"), tp->num,
 999                                target_tid_to_str (inferior_ptid));
1000               execute_command (cmd, from_tty);
1001
1002               /* Restore exact command used previously.  */
1003               strcpy (cmd, saved_cmd);
1004             }
1005         }
1006     }
1007
1008   do_cleanups (old_chain);
1009 }
1010
1011 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
1012    if prefix of arg is `apply'.  */
1013
1014 static void
1015 thread_command (char *tidstr, int from_tty)
1016 {
1017   if (!tidstr)
1018     {
1019       if (target_has_stack)
1020         {
1021           if (is_exited (inferior_ptid))
1022             printf_filtered (_("[Current thread is %d (%s) (exited)]\n"),
1023                              pid_to_thread_id (inferior_ptid),
1024                              target_tid_to_str (inferior_ptid));
1025           else
1026             printf_filtered (_("[Current thread is %d (%s)]\n"),
1027                              pid_to_thread_id (inferior_ptid),
1028                              target_tid_to_str (inferior_ptid));
1029         }
1030       else
1031         error (_("No stack."));
1032       return;
1033     }
1034
1035   annotate_thread_changed ();
1036   gdb_thread_select (uiout, tidstr, NULL);
1037 }
1038
1039 /* Print notices when new threads are attached and detached.  */
1040 int print_thread_events = 1;
1041 static void
1042 show_print_thread_events (struct ui_file *file, int from_tty,
1043                           struct cmd_list_element *c, const char *value)
1044 {
1045   fprintf_filtered (file, _("\
1046 Printing of thread events is %s.\n"),
1047                     value);
1048 }
1049
1050 static int
1051 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
1052 {
1053   int num;
1054   struct thread_info *tp;
1055
1056   num = value_as_long (parse_and_eval (tidstr));
1057
1058   tp = find_thread_id (num);
1059
1060   if (!tp)
1061     error (_("Thread ID %d not known."), num);
1062
1063   if (!thread_alive (tp))
1064     error (_("Thread ID %d has terminated."), num);
1065
1066   switch_to_thread (tp->ptid);
1067
1068   ui_out_text (uiout, "[Switching to thread ");
1069   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
1070   ui_out_text (uiout, " (");
1071   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
1072   ui_out_text (uiout, ")]");
1073
1074   /* Note that we can't reach this with an exited thread, due to the
1075      thread_alive check above.  */
1076   if (tp->state_ == THREAD_RUNNING)
1077     ui_out_text (uiout, "(running)\n");
1078   else
1079     print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
1080
1081   /* Since the current thread may have changed, see if there is any
1082      exited thread we can now delete.  */
1083   prune_threads ();
1084
1085   return GDB_RC_OK;
1086 }
1087
1088 enum gdb_rc
1089 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
1090 {
1091   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
1092                                  error_message, RETURN_MASK_ALL) < 0)
1093     return GDB_RC_FAIL;
1094   return GDB_RC_OK;
1095 }
1096
1097 /* Commands with a prefix of `thread'.  */
1098 struct cmd_list_element *thread_cmd_list = NULL;
1099
1100 void
1101 _initialize_thread (void)
1102 {
1103   static struct cmd_list_element *thread_apply_list = NULL;
1104   struct cmd_list_element *c;
1105
1106   c = add_info ("threads", info_threads_command,
1107                 _("IDs of currently known threads."));
1108   set_cmd_no_selected_thread_ok (c);
1109
1110   c = add_prefix_cmd ("thread", class_run, thread_command, _("\
1111 Use this command to switch between threads.\n\
1112 The new thread ID must be currently known."),
1113                       &thread_cmd_list, "thread ", 1, &cmdlist);
1114   set_cmd_no_selected_thread_ok (c);
1115
1116   c = add_prefix_cmd ("apply", class_run, thread_apply_command,
1117                       _("Apply a command to a list of threads."),
1118                       &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
1119   set_cmd_no_selected_thread_ok (c);
1120
1121   c = add_cmd ("all", class_run, thread_apply_all_command,
1122                _("Apply a command to all threads."), &thread_apply_list);
1123   set_cmd_no_selected_thread_ok (c);
1124
1125   if (!xdb_commands)
1126     add_com_alias ("t", "thread", class_run, 1);
1127
1128   add_setshow_boolean_cmd ("thread-events", no_class,
1129          &print_thread_events, _("\
1130 Set printing of thread events (such as thread start and exit)."), _("\
1131 Show printing of thread events (such as thread start and exit)."), NULL,
1132          NULL,
1133          show_print_thread_events,
1134          &setprintlist, &showprintlist);
1135 }