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 /* Prints the list of threads and their details on UIOUT.
 610    This is a version of 'info_thread_command' suitable for
 611    use from MI.
 612    If REQUESTED_THREAD is not -1, it's the GDB id of the thread
 613    that should be printed.  Otherwise, all threads are
 614    printed.  */
 615 void
 616 print_thread_info (struct ui_out *uiout, int requested_thread)
 617 {
 618   struct thread_info *tp;
 619   ptid_t current_ptid;
 620   struct cleanup *old_chain;
 621   char *extra_info;
 622   int current_thread = -1;
 623
 624   prune_threads ();
 625   target_find_new_threads ();
 626   current_ptid = inferior_ptid;
 627
 628   /* We'll be switching threads temporarily.  */
 629   old_chain = make_cleanup_restore_current_thread ();
 630
 631   make_cleanup_ui_out_list_begin_end (uiout, "threads");
 632   for (tp = thread_list; tp; tp = tp->next)
 633     {
 634       struct cleanup *chain2;
 635
 636       if (requested_thread != -1 && tp->num != requested_thread)
 637         continue;
 638
 639       if (ptid_equal (tp->ptid, current_ptid))
 640         current_thread = tp->num;
 641
 642       if (tp->state_ == THREAD_EXITED)
 643         continue;
 644
 645       chain2 = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 646
 647       if (ptid_equal (tp->ptid, current_ptid))
 648         ui_out_text (uiout, "* ");
 649       else
 650         ui_out_text (uiout, "  ");
 651
 652       ui_out_field_int (uiout, "id", tp->num);
 653       ui_out_text (uiout, " ");
 654       ui_out_field_string (uiout, "target-id", target_tid_to_str (tp->ptid));
 655
 656       if (tp->state_ != THREAD_EXITED)
 657         {
 658           extra_info = target_extra_thread_info (tp);
 659           if (extra_info)
 660             {
 661               ui_out_text (uiout, " (");
 662               ui_out_field_string (uiout, "details", extra_info);
 663               ui_out_text (uiout, ")");
 664             }
 665           ui_out_text (uiout, "  ");
 666         }
 667
 668       if (tp->state_ == THREAD_RUNNING)
 669         ui_out_text (uiout, "(running)\n");
 670       else
 671         {
 672           /* The switch below puts us at the top of the stack (leaf
 673              frame).  */
 674           switch_to_thread (tp->ptid);
 675           print_stack_frame (get_selected_frame (NULL),
 676                              /* For MI output, print frame level.  */
 677                              ui_out_is_mi_like_p (uiout),
 678                              LOCATION);
 679         }
 680
 681       if (ui_out_is_mi_like_p (uiout))
 682         {
 683           char *state = "stopped";
 684           if (tp->state_ == THREAD_EXITED)
 685             state = "exited";
 686           else if (tp->state_ == THREAD_RUNNING)
 687             state = "running";
 688           ui_out_field_string (uiout, "state", state);
 689         }
 690
 691       do_cleanups (chain2);
 692     }
 693
 694   /* Restores the current thread and the frame selected before
 695      the "info threads" command.  */
 696   do_cleanups (old_chain);
 697
 698   if (requested_thread == -1)
 699     {
 700       gdb_assert (current_thread != -1
 701                   || !thread_list);
 702       if (current_thread != -1 && ui_out_is_mi_like_p (uiout))
 703         ui_out_field_int (uiout, "current-thread-id", current_thread);
 704
 705       if (current_thread != -1 && is_exited (current_ptid))
 706         ui_out_message (uiout, 0, "\n\
 707 The current thread <Thread ID %d> has terminated.  See `help thread'.\n",
 708                         current_thread);
 709     }
 710 }
 711
 712
 713 /* Print information about currently known threads
 714
 715  * Note: this has the drawback that it _really_ switches
 716  *       threads, which frees the frame cache.  A no-side
 717  *       effects info-threads command would be nicer.
 718  */
 719
 720 static void
 721 info_threads_command (char *arg, int from_tty)
 722 {
 723   print_thread_info (uiout, -1);
 724 }
 725
 726 /* Switch from one thread to another. */
 727
 728 void
 729 switch_to_thread (ptid_t ptid)
 730 {
 731   if (ptid_equal (ptid, inferior_ptid))
 732     return;
 733
 734   inferior_ptid = ptid;
 735   reinit_frame_cache ();
 736   registers_changed ();
 737
 738   /* We don't check for is_stopped, because we're called at times
 739      while in the TARGET_RUNNING state, e.g., while handling an
 740      internal event.  */
 741   if (!is_exited (ptid) && !is_executing (ptid))
 742     stop_pc = read_pc ();
 743   else
 744     stop_pc = ~(CORE_ADDR) 0;
 745 }
 746
 747 static void
 748 restore_current_thread (ptid_t ptid)
 749 {
 750   switch_to_thread (ptid);
 751 }
 752
 753 static void
 754 restore_selected_frame (struct frame_id a_frame_id, int frame_level)
 755 {
 756   struct frame_info *frame = NULL;
 757   int count;
 758
 759   gdb_assert (frame_level >= 0);
 760
 761   /* Restore by level first, check if the frame id is the same as
 762      expected.  If that fails, try restoring by frame id.  If that
 763      fails, nothing to do, just warn the user.  */
 764
 765   count = frame_level;
 766   frame = find_relative_frame (get_current_frame (), &count);
 767   if (count == 0
 768       && frame != NULL
 769       /* Either the frame ids match, of they're both invalid.  The
 770          latter case is not failsafe, but since it's highly unlikely
 771          the search by level finds the wrong frame, it's 99.9(9)% of
 772          the time (for all practical purposes) safe.  */
 773       && (frame_id_eq (get_frame_id (frame), a_frame_id)
 774           /* Note: could be better to check every frame_id
 775              member for equality here.  */
 776           || (!frame_id_p (get_frame_id (frame))
 777               && !frame_id_p (a_frame_id))))
 778     {
 779       /* Cool, all is fine.  */
 780       select_frame (frame);
 781       return;
 782     }
 783
 784   frame = frame_find_by_id (a_frame_id);
 785   if (frame != NULL)
 786     {
 787       /* Cool, refound it.  */
 788       select_frame (frame);
 789       return;
 790     }
 791
 792   /* Nothing else to do, the frame layout really changed.  Select the
 793      innermost stack frame.  */
 794   select_frame (get_current_frame ());
 795
 796   /* Warn the user.  */
 797   if (!ui_out_is_mi_like_p (uiout))
 798     {
 799       warning (_("\
 800 Couldn't restore frame #%d in current thread, at reparsed frame #0\n"),
 801                frame_level);
 802       /* For MI, we should probably have a notification about
 803          current frame change.  But this error is not very
 804          likely, so don't bother for now.  */
 805       print_stack_frame (get_selected_frame (NULL), 1, SRC_LINE);
 806     }
 807 }
 808
 809 struct current_thread_cleanup
 810 {
 811   ptid_t inferior_ptid;
 812   struct frame_id selected_frame_id;
 813   int selected_frame_level;
 814   int was_stopped;
 815 };
 816
 817 static void
 818 do_restore_current_thread_cleanup (void *arg)
 819 {
 820   struct thread_info *tp;
 821   struct current_thread_cleanup *old = arg;
 822   restore_current_thread (old->inferior_ptid);
 823
 824   /* The running state of the originally selected thread may have
 825      changed, so we have to recheck it here.  */
 826   if (old->was_stopped
 827       && is_stopped (inferior_ptid)
 828       && target_has_registers
 829       && target_has_stack
 830       && target_has_memory)
 831     restore_selected_frame (old->selected_frame_id,
 832                             old->selected_frame_level);
 833 }
 834
 835 static void
 836 restore_current_thread_cleanup_dtor (void *arg)
 837 {
 838   struct current_thread_cleanup *old = arg;
 839   struct thread_info *tp;
 840   tp = find_thread_pid (old->inferior_ptid);
 841   if (tp)
 842     tp->refcount--;
 843   xfree (old);
 844 }
 845
 846 struct cleanup *
 847 make_cleanup_restore_current_thread (void)
 848 {
 849   struct thread_info *tp;
 850   struct frame_info *frame;
 851   struct current_thread_cleanup *old;
 852
 853   old = xmalloc (sizeof (struct current_thread_cleanup));
 854   old->inferior_ptid = inferior_ptid;
 855   old->was_stopped = is_stopped (inferior_ptid);
 856   if (old->was_stopped
 857       && target_has_registers
 858       && target_has_stack
 859       && target_has_memory)
 860     frame = get_selected_frame (NULL);
 861   else
 862     frame = NULL;
 863
 864   old->selected_frame_id = get_frame_id (frame);
 865   old->selected_frame_level = frame_relative_level (frame);
 866
 867   tp = find_thread_pid (inferior_ptid);
 868   if (tp)
 869     tp->refcount++;
 870
 871   return make_cleanup_dtor (do_restore_current_thread_cleanup, old,
 872                             restore_current_thread_cleanup_dtor);
 873 }
 874
 875 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 876    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 877    of two numbers seperated by a hyphen.  Examples:
 878
 879    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 880    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 881    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 882  */
 883
 884 static void
 885 thread_apply_all_command (char *cmd, int from_tty)
 886 {
 887   struct thread_info *tp;
 888   struct cleanup *old_chain;
 889   char *saved_cmd;
 890
 891   if (cmd == NULL || *cmd == '\000')
 892     error (_("Please specify a command following the thread ID list"));
 893
 894   prune_threads ();
 895   target_find_new_threads ();
 896
 897   old_chain = make_cleanup_restore_current_thread ();
 898
 899   /* Save a copy of the command in case it is clobbered by
 900      execute_command */
 901   saved_cmd = xstrdup (cmd);
 902   make_cleanup (xfree, saved_cmd);
 903   for (tp = thread_list; tp; tp = tp->next)
 904     if (thread_alive (tp))
 905       {
 906         switch_to_thread (tp->ptid);
 907
 908         printf_filtered (_("\nThread %d (%s):\n"),
 909                          tp->num, target_tid_to_str (inferior_ptid));
 910         execute_command (cmd, from_tty);
 911         strcpy (cmd, saved_cmd);        /* Restore exact command used previously */
 912       }
 913
 914   do_cleanups (old_chain);
 915 }
 916
 917 static void
 918 thread_apply_command (char *tidlist, int from_tty)
 919 {
 920   char *cmd;
 921   char *p;
 922   struct cleanup *old_chain;
 923   char *saved_cmd;
 924
 925   if (tidlist == NULL || *tidlist == '\000')
 926     error (_("Please specify a thread ID list"));
 927
 928   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 929
 930   if (*cmd == '\000')
 931     error (_("Please specify a command following the thread ID list"));
 932
 933   /* Save a copy of the command in case it is clobbered by
 934      execute_command */
 935   saved_cmd = xstrdup (cmd);
 936   old_chain = make_cleanup (xfree, saved_cmd);
 937   while (tidlist < cmd)
 938     {
 939       struct thread_info *tp;
 940       int start, end;
 941
 942       start = strtol (tidlist, &p, 10);
 943       if (p == tidlist)
 944         error (_("Error parsing %s"), tidlist);
 945       tidlist = p;
 946
 947       while (*tidlist == ' ' || *tidlist == '\t')
 948         tidlist++;
 949
 950       if (*tidlist == '-')      /* Got a range of IDs? */
 951         {
 952           tidlist++;            /* Skip the - */
 953           end = strtol (tidlist, &p, 10);
 954           if (p == tidlist)
 955             error (_("Error parsing %s"), tidlist);
 956           tidlist = p;
 957
 958           while (*tidlist == ' ' || *tidlist == '\t')
 959             tidlist++;
 960         }
 961       else
 962         end = start;
 963
 964       make_cleanup_restore_current_thread ();
 965
 966       for (; start <= end; start++)
 967         {
 968           tp = find_thread_id (start);
 969
 970           if (!tp)
 971             warning (_("Unknown thread %d."), start);
 972           else if (!thread_alive (tp))
 973             warning (_("Thread %d has terminated."), start);
 974           else
 975             {
 976               switch_to_thread (tp->ptid);
 977
 978               printf_filtered (_("\nThread %d (%s):\n"), tp->num,
 979                                target_tid_to_str (inferior_ptid));
 980               execute_command (cmd, from_tty);
 981
 982               /* Restore exact command used previously.  */
 983               strcpy (cmd, saved_cmd);
 984             }
 985         }
 986     }
 987
 988   do_cleanups (old_chain);
 989 }
 990
 991 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
 992    if prefix of arg is `apply'.  */
 993
 994 static void
 995 thread_command (char *tidstr, int from_tty)
 996 {
 997   if (!tidstr)
 998     {
 999       if (target_has_stack)
1000         {
1001           if (is_exited (inferior_ptid))
1002             printf_filtered (_("[Current thread is %d (%s) (exited)]\n"),
1003                              pid_to_thread_id (inferior_ptid),
1004                              target_tid_to_str (inferior_ptid));
1005           else
1006             printf_filtered (_("[Current thread is %d (%s)]\n"),
1007                              pid_to_thread_id (inferior_ptid),
1008                              target_tid_to_str (inferior_ptid));
1009         }
1010       else
1011         error (_("No stack."));
1012       return;
1013     }
1014
1015   annotate_thread_changed ();
1016   gdb_thread_select (uiout, tidstr, NULL);
1017 }
1018
1019 /* Print notices when new threads are attached and detached.  */
1020 int print_thread_events = 1;
1021 static void
1022 show_print_thread_events (struct ui_file *file, int from_tty,
1023                           struct cmd_list_element *c, const char *value)
1024 {
1025   fprintf_filtered (file, _("\
1026 Printing of thread events is %s.\n"),
1027                     value);
1028 }
1029
1030 static int
1031 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
1032 {
1033   int num;
1034   struct thread_info *tp;
1035
1036   num = value_as_long (parse_and_eval (tidstr));
1037
1038   tp = find_thread_id (num);
1039
1040   if (!tp)
1041     error (_("Thread ID %d not known."), num);
1042
1043   if (!thread_alive (tp))
1044     error (_("Thread ID %d has terminated."), num);
1045
1046   switch_to_thread (tp->ptid);
1047
1048   ui_out_text (uiout, "[Switching to thread ");
1049   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
1050   ui_out_text (uiout, " (");
1051   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
1052   ui_out_text (uiout, ")]");
1053
1054   /* Note that we can't reach this with an exited thread, due to the
1055      thread_alive check above.  */
1056   if (tp->state_ == THREAD_RUNNING)
1057     ui_out_text (uiout, "(running)\n");
1058   else
1059     print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
1060
1061   /* Since the current thread may have changed, see if there is any
1062      exited thread we can now delete.  */
1063   prune_threads ();
1064
1065   return GDB_RC_OK;
1066 }
1067
1068 enum gdb_rc
1069 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
1070 {
1071   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
1072                                  error_message, RETURN_MASK_ALL) < 0)
1073     return GDB_RC_FAIL;
1074   return GDB_RC_OK;
1075 }
1076
1077 /* Commands with a prefix of `thread'.  */
1078 struct cmd_list_element *thread_cmd_list = NULL;
1079
1080 void
1081 _initialize_thread (void)
1082 {
1083   static struct cmd_list_element *thread_apply_list = NULL;
1084   struct cmd_list_element *c;
1085
1086   c = add_info ("threads", info_threads_command,
1087                 _("IDs of currently known threads."));
1088   set_cmd_no_selected_thread_ok (c);
1089
1090   c = add_prefix_cmd ("thread", class_run, thread_command, _("\
1091 Use this command to switch between threads.\n\
1092 The new thread ID must be currently known."),
1093                       &thread_cmd_list, "thread ", 1, &cmdlist);
1094   set_cmd_no_selected_thread_ok (c);
1095
1096   c = add_prefix_cmd ("apply", class_run, thread_apply_command,
1097                       _("Apply a command to a list of threads."),
1098                       &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
1099   set_cmd_no_selected_thread_ok (c);
1100
1101   c = add_cmd ("all", class_run, thread_apply_all_command,
1102                _("Apply a command to all threads."), &thread_apply_list);
1103   set_cmd_no_selected_thread_ok (c);
1104
1105   if (!xdb_commands)
1106     add_com_alias ("t", "thread", class_run, 1);
1107
1108   add_setshow_boolean_cmd ("thread-events", no_class,
1109          &print_thread_events, _("\
1110 Set printing of thread events (such as thread start and exit)."), _("\
1111 Show printing of thread events (such as thread start and exit)."), NULL,
1112          NULL,
1113          show_print_thread_events,
1114          &setprintlist, &showprintlist);
1115 }