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, 2009, 2010, 2011
   5    Free Software Foundation, Inc.
   6
   7    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   8
   9    This file is part of GDB.
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 3 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  23
  24 #include "defs.h"
  25 #include "symtab.h"
  26 #include "frame.h"
  27 #include "inferior.h"
  28 #include "environ.h"
  29 #include "value.h"
  30 #include "target.h"
  31 #include "gdbthread.h"
  32 #include "exceptions.h"
  33 #include "command.h"
  34 #include "gdbcmd.h"
  35 #include "regcache.h"
  36 #include "gdb.h"
  37 #include "gdb_string.h"
  38
  39 #include <ctype.h>
  40 #include <sys/types.h>
  41 #include <signal.h>
  42 #include "ui-out.h"
  43 #include "observer.h"
  44 #include "annotate.h"
  45 #include "cli/cli-decode.h"
  46 #include "gdb_regex.h"
  47
  48 /* Definition of struct thread_info exported to gdbthread.h.  */
  49
  50 /* Prototypes for exported functions.  */
  51
  52 void _initialize_thread (void);
  53
  54 /* Prototypes for local functions.  */
  55
  56 static struct thread_info *thread_list = NULL;
  57 static int highest_thread_num;
  58
  59 static void thread_command (char *tidstr, int from_tty);
  60 static void thread_apply_all_command (char *, int);
  61 static int thread_alive (struct thread_info *);
  62 static void info_threads_command (char *, int);
  63 static void thread_apply_command (char *, int);
  64 static void restore_current_thread (ptid_t);
  65 static void prune_threads (void);
  66
  67 /* Frontend view of the thread state.  Possible extensions: stepping,
  68    finishing, until(ling),...  */
  69 enum thread_state
  70 {
  71   THREAD_STOPPED,
  72   THREAD_RUNNING,
  73   THREAD_EXITED,
  74 };
  75
  76 struct thread_info*
  77 inferior_thread (void)
  78 {
  79   struct thread_info *tp = find_thread_ptid (inferior_ptid);
  80   gdb_assert (tp);
  81   return tp;
  82 }
  83
  84 void
  85 delete_step_resume_breakpoint (struct thread_info *tp)
  86 {
  87   if (tp && tp->control.step_resume_breakpoint)
  88     {
  89       delete_breakpoint (tp->control.step_resume_breakpoint);
  90       tp->control.step_resume_breakpoint = NULL;
  91     }
  92 }
  93
  94 void
  95 delete_exception_resume_breakpoint (struct thread_info *tp)
  96 {
  97   if (tp && tp->control.exception_resume_breakpoint)
  98     {
  99       delete_breakpoint (tp->control.exception_resume_breakpoint);
 100       tp->control.exception_resume_breakpoint = NULL;
 101     }
 102 }
 103
 104 static void
 105 clear_thread_inferior_resources (struct thread_info *tp)
 106 {
 107   /* NOTE: this will take care of any left-over step_resume breakpoints,
 108      but not any user-specified thread-specific breakpoints.  We can not
 109      delete the breakpoint straight-off, because the inferior might not
 110      be stopped at the moment.  */
 111   if (tp->control.step_resume_breakpoint)
 112     {
 113       tp->control.step_resume_breakpoint->disposition = disp_del_at_next_stop;
 114       tp->control.step_resume_breakpoint = NULL;
 115     }
 116
 117   if (tp->control.exception_resume_breakpoint)
 118     {
 119       tp->control.exception_resume_breakpoint->disposition
 120         = disp_del_at_next_stop;
 121       tp->control.exception_resume_breakpoint = NULL;
 122     }
 123
 124   bpstat_clear (&tp->control.stop_bpstat);
 125
 126   discard_all_intermediate_continuations_thread (tp);
 127   discard_all_continuations_thread (tp);
 128
 129   delete_longjmp_breakpoint (tp->num);
 130 }
 131
 132 static void
 133 free_thread (struct thread_info *tp)
 134 {
 135   clear_thread_inferior_resources (tp);
 136
 137   if (tp->private)
 138     {
 139       if (tp->private_dtor)
 140         tp->private_dtor (tp->private);
 141       else
 142         xfree (tp->private);
 143     }
 144
 145   xfree (tp->name);
 146   xfree (tp);
 147 }
 148
 149 void
 150 init_thread_list (void)
 151 {
 152   struct thread_info *tp, *tpnext;
 153
 154   highest_thread_num = 0;
 155
 156   if (!thread_list)
 157     return;
 158
 159   for (tp = thread_list; tp; tp = tpnext)
 160     {
 161       tpnext = tp->next;
 162       free_thread (tp);
 163     }
 164
 165   thread_list = NULL;
 166 }
 167
 168 /* Allocate a new thread with target id PTID and add it to the thread
 169    list.  */
 170
 171 static struct thread_info *
 172 new_thread (ptid_t ptid)
 173 {
 174   struct thread_info *tp;
 175
 176   tp = xcalloc (1, sizeof (*tp));
 177
 178   tp->ptid = ptid;
 179   tp->num = ++highest_thread_num;
 180   tp->next = thread_list;
 181   thread_list = tp;
 182
 183   /* Nothing to follow yet.  */
 184   tp->pending_follow.kind = TARGET_WAITKIND_SPURIOUS;
 185   tp->state_ = THREAD_STOPPED;
 186
 187   return tp;
 188 }
 189
 190 struct thread_info *
 191 add_thread_silent (ptid_t ptid)
 192 {
 193   struct thread_info *tp;
 194
 195   tp = find_thread_ptid (ptid);
 196   if (tp)
 197     /* Found an old thread with the same id.  It has to be dead,
 198        otherwise we wouldn't be adding a new thread with the same id.
 199        The OS is reusing this id --- delete it, and recreate a new
 200        one.  */
 201     {
 202       /* In addition to deleting the thread, if this is the current
 203          thread, then we need to take care that delete_thread doesn't
 204          really delete the thread if it is inferior_ptid.  Create a
 205          new template thread in the list with an invalid ptid, switch
 206          to it, delete the original thread, reset the new thread's
 207          ptid, and switch to it.  */
 208
 209       if (ptid_equal (inferior_ptid, ptid))
 210         {
 211           tp = new_thread (null_ptid);
 212
 213           /* Make switch_to_thread not read from the thread.  */
 214           tp->state_ = THREAD_EXITED;
 215           switch_to_thread (null_ptid);
 216
 217           /* Now we can delete it.  */
 218           delete_thread (ptid);
 219
 220           /* Now reset its ptid, and reswitch inferior_ptid to it.  */
 221           tp->ptid = ptid;
 222           tp->state_ = THREAD_STOPPED;
 223           switch_to_thread (ptid);
 224
 225           observer_notify_new_thread (tp);
 226
 227           /* All done.  */
 228           return tp;
 229         }
 230       else
 231         /* Just go ahead and delete it.  */
 232         delete_thread (ptid);
 233     }
 234
 235   tp = new_thread (ptid);
 236   observer_notify_new_thread (tp);
 237
 238   return tp;
 239 }
 240
 241 struct thread_info *
 242 add_thread_with_info (ptid_t ptid, struct private_thread_info *private)
 243 {
 244   struct thread_info *result = add_thread_silent (ptid);
 245
 246   result->private = private;
 247
 248   if (print_thread_events)
 249     printf_unfiltered (_("[New %s]\n"), target_pid_to_str (ptid));
 250
 251   annotate_new_thread ();
 252   return result;
 253 }
 254
 255 struct thread_info *
 256 add_thread (ptid_t ptid)
 257 {
 258   return add_thread_with_info (ptid, NULL);
 259 }
 260
 261 /* Delete thread PTID.  If SILENT, don't notify the observer of this
 262    exit.  */
 263 static void
 264 delete_thread_1 (ptid_t ptid, int silent)
 265 {
 266   struct thread_info *tp, *tpprev;
 267
 268   tpprev = NULL;
 269
 270   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 271     if (ptid_equal (tp->ptid, ptid))
 272       break;
 273
 274   if (!tp)
 275     return;
 276
 277   /* If this is the current thread, or there's code out there that
 278      relies on it existing (refcount > 0) we can't delete yet.  Mark
 279      it as exited, and notify it.  */
 280   if (tp->refcount > 0
 281       || ptid_equal (tp->ptid, inferior_ptid))
 282     {
 283       if (tp->state_ != THREAD_EXITED)
 284         {
 285           observer_notify_thread_exit (tp, silent);
 286
 287           /* Tag it as exited.  */
 288           tp->state_ = THREAD_EXITED;
 289
 290           /* Clear breakpoints, etc. associated with this thread.  */
 291           clear_thread_inferior_resources (tp);
 292         }
 293
 294        /* Will be really deleted some other time.  */
 295        return;
 296      }
 297
 298   if (tpprev)
 299     tpprev->next = tp->next;
 300   else
 301     thread_list = tp->next;
 302
 303   /* Notify thread exit, but only if we haven't already.  */
 304   if (tp->state_ != THREAD_EXITED)
 305     observer_notify_thread_exit (tp, silent);
 306
 307   free_thread (tp);
 308 }
 309
 310 /* Delete thread PTID and notify of thread exit.  If this is
 311    inferior_ptid, don't actually delete it, but tag it as exited and
 312    do the notification.  If PTID is the user selected thread, clear
 313    it.  */
 314 void
 315 delete_thread (ptid_t ptid)
 316 {
 317   delete_thread_1 (ptid, 0 /* not silent */);
 318 }
 319
 320 void
 321 delete_thread_silent (ptid_t ptid)
 322 {
 323   delete_thread_1 (ptid, 1 /* silent */);
 324 }
 325
 326 struct thread_info *
 327 find_thread_id (int num)
 328 {
 329   struct thread_info *tp;
 330
 331   for (tp = thread_list; tp; tp = tp->next)
 332     if (tp->num == num)
 333       return tp;
 334
 335   return NULL;
 336 }
 337
 338 /* Find a thread_info by matching PTID.  */
 339 struct thread_info *
 340 find_thread_ptid (ptid_t ptid)
 341 {
 342   struct thread_info *tp;
 343
 344   for (tp = thread_list; tp; tp = tp->next)
 345     if (ptid_equal (tp->ptid, ptid))
 346       return tp;
 347
 348   return NULL;
 349 }
 350
 351 /*
 352  * Thread iterator function.
 353  *
 354  * Calls a callback function once for each thread, so long as
 355  * the callback function returns false.  If the callback function
 356  * returns true, the iteration will end and the current thread
 357  * will be returned.  This can be useful for implementing a
 358  * search for a thread with arbitrary attributes, or for applying
 359  * some operation to every thread.
 360  *
 361  * FIXME: some of the existing functionality, such as
 362  * "Thread apply all", might be rewritten using this functionality.
 363  */
 364
 365 struct thread_info *
 366 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 367                       void *data)
 368 {
 369   struct thread_info *tp, *next;
 370
 371   for (tp = thread_list; tp; tp = next)
 372     {
 373       next = tp->next;
 374       if ((*callback) (tp, data))
 375         return tp;
 376     }
 377
 378   return NULL;
 379 }
 380
 381 int
 382 thread_count (void)
 383 {
 384   int result = 0;
 385   struct thread_info *tp;
 386
 387   for (tp = thread_list; tp; tp = tp->next)
 388     ++result;
 389
 390   return result;
 391 }
 392
 393 int
 394 valid_thread_id (int num)
 395 {
 396   struct thread_info *tp;
 397
 398   for (tp = thread_list; tp; tp = tp->next)
 399     if (tp->num == num)
 400       return 1;
 401
 402   return 0;
 403 }
 404
 405 int
 406 pid_to_thread_id (ptid_t ptid)
 407 {
 408   struct thread_info *tp;
 409
 410   for (tp = thread_list; tp; tp = tp->next)
 411     if (ptid_equal (tp->ptid, ptid))
 412       return tp->num;
 413
 414   return 0;
 415 }
 416
 417 ptid_t
 418 thread_id_to_pid (int num)
 419 {
 420   struct thread_info *thread = find_thread_id (num);
 421
 422   if (thread)
 423     return thread->ptid;
 424   else
 425     return pid_to_ptid (-1);
 426 }
 427
 428 int
 429 in_thread_list (ptid_t ptid)
 430 {
 431   struct thread_info *tp;
 432
 433   for (tp = thread_list; tp; tp = tp->next)
 434     if (ptid_equal (tp->ptid, ptid))
 435       return 1;
 436
 437   return 0;                     /* Never heard of 'im.  */
 438 }
 439
 440 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 441    return the first thread in the list.  */
 442
 443 struct thread_info *
 444 first_thread_of_process (int pid)
 445 {
 446   struct thread_info *tp, *ret = NULL;
 447
 448   for (tp = thread_list; tp; tp = tp->next)
 449     if (pid == -1 || ptid_get_pid (tp->ptid) == pid)
 450       if (ret == NULL || tp->num < ret->num)
 451         ret = tp;
 452
 453   return ret;
 454 }
 455
 456 struct thread_info *
 457 any_thread_of_process (int pid)
 458 {
 459   struct thread_info *tp;
 460
 461   for (tp = thread_list; tp; tp = tp->next)
 462     if (ptid_get_pid (tp->ptid) == pid)
 463       return tp;
 464
 465   return NULL;
 466 }
 467
 468 struct thread_info *
 469 any_live_thread_of_process (int pid)
 470 {
 471   struct thread_info *tp;
 472   struct thread_info *tp_running = NULL;
 473
 474   for (tp = thread_list; tp; tp = tp->next)
 475     if (ptid_get_pid (tp->ptid) == pid)
 476       {
 477         if (tp->state_ == THREAD_STOPPED)
 478           return tp;
 479         else if (tp->state_ == THREAD_RUNNING)
 480           tp_running = tp;
 481       }
 482
 483   return tp_running;
 484 }
 485
 486 /* Print a list of thread ids currently known, and the total number of
 487    threads.  To be used from within catch_errors.  */
 488 static int
 489 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 490 {
 491   struct thread_info *tp;
 492   int num = 0;
 493   struct cleanup *cleanup_chain;
 494   int current_thread = -1;
 495
 496   update_thread_list ();
 497
 498   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 499
 500   for (tp = thread_list; tp; tp = tp->next)
 501     {
 502       if (tp->state_ == THREAD_EXITED)
 503         continue;
 504
 505       if (ptid_equal (tp->ptid, inferior_ptid))
 506         current_thread = tp->num;
 507
 508       num++;
 509       ui_out_field_int (uiout, "thread-id", tp->num);
 510     }
 511
 512   do_cleanups (cleanup_chain);
 513
 514   if (current_thread != -1)
 515     ui_out_field_int (uiout, "current-thread-id", current_thread);
 516   ui_out_field_int (uiout, "number-of-threads", num);
 517   return GDB_RC_OK;
 518 }
 519
 520 /* Official gdblib interface function to get a list of thread ids and
 521    the total number.  */
 522 enum gdb_rc
 523 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 524 {
 525   if (catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 526                                  error_message, RETURN_MASK_ALL) < 0)
 527     return GDB_RC_FAIL;
 528   return GDB_RC_OK;
 529 }
 530
 531 /* Return true if TP is an active thread.  */
 532 static int
 533 thread_alive (struct thread_info *tp)
 534 {
 535   if (tp->state_ == THREAD_EXITED)
 536     return 0;
 537   if (!target_thread_alive (tp->ptid))
 538     return 0;
 539   return 1;
 540 }
 541
 542 static void
 543 prune_threads (void)
 544 {
 545   struct thread_info *tp, *next;
 546
 547   for (tp = thread_list; tp; tp = next)
 548     {
 549       next = tp->next;
 550       if (!thread_alive (tp))
 551         delete_thread (tp->ptid);
 552     }
 553 }
 554
 555 void
 556 thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid)
 557 {
 558   struct inferior *inf;
 559   struct thread_info *tp;
 560
 561   /* It can happen that what we knew as the target inferior id
 562      changes.  E.g, target remote may only discover the remote process
 563      pid after adding the inferior to GDB's list.  */
 564   inf = find_inferior_pid (ptid_get_pid (old_ptid));
 565   inf->pid = ptid_get_pid (new_ptid);
 566
 567   tp = find_thread_ptid (old_ptid);
 568   tp->ptid = new_ptid;
 569
 570   observer_notify_thread_ptid_changed (old_ptid, new_ptid);
 571 }
 572
 573 void
 574 set_running (ptid_t ptid, int running)
 575 {
 576   struct thread_info *tp;
 577   int all = ptid_equal (ptid, minus_one_ptid);
 578
 579   /* We try not to notify the observer if no thread has actually changed
 580      the running state -- merely to reduce the number of messages to
 581      frontend.  Frontend is supposed to handle multiple *running just fine.  */
 582   if (all || ptid_is_pid (ptid))
 583     {
 584       int any_started = 0;
 585
 586       for (tp = thread_list; tp; tp = tp->next)
 587         if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
 588           {
 589             if (tp->state_ == THREAD_EXITED)
 590               continue;
 591             if (running && tp->state_ == THREAD_STOPPED)
 592               any_started = 1;
 593             tp->state_ = running ? THREAD_RUNNING : THREAD_STOPPED;
 594           }
 595       if (any_started)
 596         observer_notify_target_resumed (ptid);
 597     }
 598   else
 599     {
 600       int started = 0;
 601
 602       tp = find_thread_ptid (ptid);
 603       gdb_assert (tp);
 604       gdb_assert (tp->state_ != THREAD_EXITED);
 605       if (running && tp->state_ == THREAD_STOPPED)
 606         started = 1;
 607       tp->state_ = running ? THREAD_RUNNING : THREAD_STOPPED;
 608       if (started)
 609         observer_notify_target_resumed (ptid);
 610     }
 611 }
 612
 613 static int
 614 is_thread_state (ptid_t ptid, enum thread_state state)
 615 {
 616   struct thread_info *tp;
 617
 618   tp = find_thread_ptid (ptid);
 619   gdb_assert (tp);
 620   return tp->state_ == state;
 621 }
 622
 623 int
 624 is_stopped (ptid_t ptid)
 625 {
 626   return is_thread_state (ptid, THREAD_STOPPED);
 627 }
 628
 629 int
 630 is_exited (ptid_t ptid)
 631 {
 632   return is_thread_state (ptid, THREAD_EXITED);
 633 }
 634
 635 int
 636 is_running (ptid_t ptid)
 637 {
 638   return is_thread_state (ptid, THREAD_RUNNING);
 639 }
 640
 641 int
 642 any_running (void)
 643 {
 644   struct thread_info *tp;
 645
 646   for (tp = thread_list; tp; tp = tp->next)
 647     if (tp->state_ == THREAD_RUNNING)
 648       return 1;
 649
 650   return 0;
 651 }
 652
 653 int
 654 is_executing (ptid_t ptid)
 655 {
 656   struct thread_info *tp;
 657
 658   tp = find_thread_ptid (ptid);
 659   gdb_assert (tp);
 660   return tp->executing_;
 661 }
 662
 663 void
 664 set_executing (ptid_t ptid, int executing)
 665 {
 666   struct thread_info *tp;
 667   int all = ptid_equal (ptid, minus_one_ptid);
 668
 669   if (all || ptid_is_pid (ptid))
 670     {
 671       for (tp = thread_list; tp; tp = tp->next)
 672         if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
 673           tp->executing_ = executing;
 674     }
 675   else
 676     {
 677       tp = find_thread_ptid (ptid);
 678       gdb_assert (tp);
 679       tp->executing_ = executing;
 680     }
 681 }
 682
 683 void
 684 set_stop_requested (ptid_t ptid, int stop)
 685 {
 686   struct thread_info *tp;
 687   int all = ptid_equal (ptid, minus_one_ptid);
 688
 689   if (all || ptid_is_pid (ptid))
 690     {
 691       for (tp = thread_list; tp; tp = tp->next)
 692         if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
 693           tp->stop_requested = stop;
 694     }
 695   else
 696     {
 697       tp = find_thread_ptid (ptid);
 698       gdb_assert (tp);
 699       tp->stop_requested = stop;
 700     }
 701
 702   /* Call the stop requested observer so other components of GDB can
 703      react to this request.  */
 704   if (stop)
 705     observer_notify_thread_stop_requested (ptid);
 706 }
 707
 708 void
 709 finish_thread_state (ptid_t ptid)
 710 {
 711   struct thread_info *tp;
 712   int all;
 713   int any_started = 0;
 714
 715   all = ptid_equal (ptid, minus_one_ptid);
 716
 717   if (all || ptid_is_pid (ptid))
 718     {
 719       for (tp = thread_list; tp; tp = tp->next)
 720         {
 721           if (tp->state_ == THREAD_EXITED)
 722             continue;
 723           if (all || ptid_get_pid (ptid) == ptid_get_pid (tp->ptid))
 724             {
 725               if (tp->executing_ && tp->state_ == THREAD_STOPPED)
 726                 any_started = 1;
 727               tp->state_ = tp->executing_ ? THREAD_RUNNING : THREAD_STOPPED;
 728             }
 729         }
 730     }
 731   else
 732     {
 733       tp = find_thread_ptid (ptid);
 734       gdb_assert (tp);
 735       if (tp->state_ != THREAD_EXITED)
 736         {
 737           if (tp->executing_ && tp->state_ == THREAD_STOPPED)
 738             any_started = 1;
 739           tp->state_ = tp->executing_ ? THREAD_RUNNING : THREAD_STOPPED;
 740         }
 741     }
 742
 743   if (any_started)
 744     observer_notify_target_resumed (ptid);
 745 }
 746
 747 void
 748 finish_thread_state_cleanup (void *arg)
 749 {
 750   ptid_t *ptid_p = arg;
 751
 752   gdb_assert (arg);
 753
 754   finish_thread_state (*ptid_p);
 755 }
 756
 757 /* Prints the list of threads and their details on UIOUT.
 758    This is a version of 'info_thread_command' suitable for
 759    use from MI.
 760    If REQUESTED_THREAD is not -1, it's the GDB id of the thread
 761    that should be printed.  Otherwise, all threads are
 762    printed.
 763    If PID is not -1, only print threads from the process PID.
 764    Otherwise, threads from all attached PIDs are printed.
 765    If both REQUESTED_THREAD and PID are not -1, then the thread
 766    is printed if it belongs to the specified process.  Otherwise,
 767    an error is raised.  */
 768 void
 769 print_thread_info (struct ui_out *uiout, int requested_thread, int pid)
 770 {
 771   struct thread_info *tp;
 772   ptid_t current_ptid;
 773   struct cleanup *old_chain;
 774   char *extra_info, *name, *target_id;
 775   int current_thread = -1;
 776
 777   update_thread_list ();
 778   current_ptid = inferior_ptid;
 779
 780   /* We'll be switching threads temporarily.  */
 781   old_chain = make_cleanup_restore_current_thread ();
 782
 783   /* For backward compatibility, we make a list for MI.  A table is
 784      preferable for the CLI, though, because it shows table
 785      headers.  */
 786   if (ui_out_is_mi_like_p (uiout))
 787     make_cleanup_ui_out_list_begin_end (uiout, "threads");
 788   else
 789     {
 790       int n_threads = 0;
 791
 792       for (tp = thread_list; tp; tp = tp->next)
 793         {
 794           if (requested_thread != -1 && tp->num != requested_thread)
 795             continue;
 796
 797           if (pid != -1 && PIDGET (tp->ptid) != pid)
 798             continue;
 799
 800           if (tp->state_ == THREAD_EXITED)
 801             continue;
 802
 803           ++n_threads;
 804         }
 805
 806       if (n_threads == 0)
 807         {
 808           if (requested_thread == -1)
 809             ui_out_message (uiout, 0, _("No threads.\n"));
 810           else
 811             ui_out_message (uiout, 0, _("No thread %d.\n"), requested_thread);
 812           do_cleanups (old_chain);
 813           return;
 814         }
 815
 816       make_cleanup_ui_out_table_begin_end (uiout, 4, n_threads, "threads");
 817
 818       ui_out_table_header (uiout, 1, ui_left, "current", "");
 819       ui_out_table_header (uiout, 4, ui_left, "id", "Id");
 820       ui_out_table_header (uiout, 17, ui_left, "target-id", "Target Id");
 821       ui_out_table_header (uiout, 1, ui_left, "frame", "Frame");
 822       ui_out_table_body (uiout);
 823     }
 824
 825   for (tp = thread_list; tp; tp = tp->next)
 826     {
 827       struct cleanup *chain2;
 828       int core;
 829
 830       if (requested_thread != -1 && tp->num != requested_thread)
 831         continue;
 832
 833       if (pid != -1 && PIDGET (tp->ptid) != pid)
 834         {
 835           if (requested_thread != -1)
 836             error (_("Requested thread not found in requested process"));
 837           continue;
 838         }
 839
 840       if (ptid_equal (tp->ptid, current_ptid))
 841         current_thread = tp->num;
 842
 843       if (tp->state_ == THREAD_EXITED)
 844         continue;
 845
 846       chain2 = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 847
 848       if (ui_out_is_mi_like_p (uiout))
 849         {
 850           /* Compatibility.  */
 851           if (ptid_equal (tp->ptid, current_ptid))
 852             ui_out_text (uiout, "* ");
 853           else
 854             ui_out_text (uiout, "  ");
 855         }
 856       else
 857         {
 858           if (ptid_equal (tp->ptid, current_ptid))
 859             ui_out_field_string (uiout, "current", "*");
 860           else
 861             ui_out_field_skip (uiout, "current");
 862         }
 863
 864       ui_out_field_int (uiout, "id", tp->num);
 865
 866       /* For the CLI, we stuff everything into the target-id field.
 867          This is a gross hack to make the output come out looking
 868          correct.  The underlying problem here is that ui-out has no
 869          way to specify that a field's space allocation should be
 870          shared by several fields.  For MI, we do the right thing
 871          instead.  */
 872
 873       target_id = target_pid_to_str (tp->ptid);
 874       extra_info = target_extra_thread_info (tp);
 875       name = tp->name ? tp->name : target_thread_name (tp);
 876
 877       if (ui_out_is_mi_like_p (uiout))
 878         {
 879           ui_out_field_string (uiout, "target-id", target_id);
 880           if (extra_info)
 881             ui_out_field_string (uiout, "details", extra_info);
 882           if (name)
 883             ui_out_field_string (uiout, "name", name);
 884         }
 885       else
 886         {
 887           struct cleanup *str_cleanup;
 888           char *contents;
 889
 890           if (extra_info && name)
 891             contents = xstrprintf ("%s \"%s\" (%s)", target_id,
 892                                    name, extra_info);
 893           else if (extra_info)
 894             contents = xstrprintf ("%s (%s)", target_id, extra_info);
 895           else if (name)
 896             contents = xstrprintf ("%s \"%s\"", target_id, name);
 897           else
 898             contents = xstrdup (target_id);
 899           str_cleanup = make_cleanup (xfree, contents);
 900
 901           ui_out_field_string (uiout, "target-id", contents);
 902           do_cleanups (str_cleanup);
 903         }
 904
 905       if (tp->state_ == THREAD_RUNNING)
 906         ui_out_text (uiout, "(running)\n");
 907       else
 908         {
 909           /* The switch below puts us at the top of the stack (leaf
 910              frame).  */
 911           switch_to_thread (tp->ptid);
 912           print_stack_frame (get_selected_frame (NULL),
 913                              /* For MI output, print frame level.  */
 914                              ui_out_is_mi_like_p (uiout),
 915                              LOCATION);
 916         }
 917
 918       if (ui_out_is_mi_like_p (uiout))
 919         {
 920           char *state = "stopped";
 921
 922           if (tp->state_ == THREAD_RUNNING)
 923             state = "running";
 924           ui_out_field_string (uiout, "state", state);
 925         }
 926
 927       core = target_core_of_thread (tp->ptid);
 928       if (ui_out_is_mi_like_p (uiout) && core != -1)
 929         ui_out_field_int (uiout, "core", core);
 930
 931       do_cleanups (chain2);
 932     }
 933
 934   /* Restores the current thread and the frame selected before
 935      the "info threads" command.  */
 936   do_cleanups (old_chain);
 937
 938   if (pid == -1 && requested_thread == -1)
 939     {
 940       gdb_assert (current_thread != -1
 941                   || !thread_list
 942                   || ptid_equal (inferior_ptid, null_ptid));
 943       if (current_thread != -1 && ui_out_is_mi_like_p (uiout))
 944         ui_out_field_int (uiout, "current-thread-id", current_thread);
 945
 946       if (current_thread != -1 && is_exited (current_ptid))
 947         ui_out_message (uiout, 0, "\n\
 948 The current thread <Thread ID %d> has terminated.  See `help thread'.\n",
 949                         current_thread);
 950       else if (thread_list
 951                && current_thread == -1
 952                && ptid_equal (current_ptid, null_ptid))
 953         ui_out_message (uiout, 0, "\n\
 954 No selected thread.  See `help thread'.\n");
 955     }
 956 }
 957
 958 /* Print information about currently known threads
 959
 960    Optional ARG is a thread id, or list of thread ids.
 961
 962    Note: this has the drawback that it _really_ switches
 963          threads, which frees the frame cache.  A no-side
 964          effects info-threads command would be nicer.  */
 965
 966 static void
 967 info_threads_command (char *arg, int from_tty)
 968 {
 969   int tid = -1;
 970
 971   if (arg == NULL || *arg == '\0')
 972     {
 973       print_thread_info (uiout, -1, -1);
 974       return;
 975     }
 976
 977   while (arg != NULL && *arg != '\0')
 978     {
 979       tid = get_number_or_range (&arg);
 980
 981       if (tid <= 0)
 982         error (_("invalid thread id %d"), tid);
 983
 984       print_thread_info (uiout, tid, -1);
 985     }
 986 }
 987
 988 /* Switch from one thread to another.  */
 989
 990 void
 991 switch_to_thread (ptid_t ptid)
 992 {
 993   /* Switch the program space as well, if we can infer it from the now
 994      current thread.  Otherwise, it's up to the caller to select the
 995      space it wants.  */
 996   if (!ptid_equal (ptid, null_ptid))
 997     {
 998       struct inferior *inf;
 999
1000       inf = find_inferior_pid (ptid_get_pid (ptid));
1001       gdb_assert (inf != NULL);
1002       set_current_program_space (inf->pspace);
1003       set_current_inferior (inf);
1004     }
1005
1006   if (ptid_equal (ptid, inferior_ptid))
1007     return;
1008
1009   inferior_ptid = ptid;
1010   reinit_frame_cache ();
1011   registers_changed ();
1012
1013   /* We don't check for is_stopped, because we're called at times
1014      while in the TARGET_RUNNING state, e.g., while handling an
1015      internal event.  */
1016   if (!ptid_equal (inferior_ptid, null_ptid)
1017       && !is_exited (ptid)
1018       && !is_executing (ptid))
1019     stop_pc = regcache_read_pc (get_thread_regcache (ptid));
1020   else
1021     stop_pc = ~(CORE_ADDR) 0;
1022 }
1023
1024 static void
1025 restore_current_thread (ptid_t ptid)
1026 {
1027   switch_to_thread (ptid);
1028 }
1029
1030 static void
1031 restore_selected_frame (struct frame_id a_frame_id, int frame_level)
1032 {
1033   struct frame_info *frame = NULL;
1034   int count;
1035
1036   gdb_assert (frame_level >= 0);
1037
1038   /* Restore by level first, check if the frame id is the same as
1039      expected.  If that fails, try restoring by frame id.  If that
1040      fails, nothing to do, just warn the user.  */
1041
1042   count = frame_level;
1043   frame = find_relative_frame (get_current_frame (), &count);
1044   if (count == 0
1045       && frame != NULL
1046       /* The frame ids must match - either both valid or both outer_frame_id.
1047          The latter case is not failsafe, but since it's highly unlikely
1048          the search by level finds the wrong frame, it's 99.9(9)% of
1049          the time (for all practical purposes) safe.  */
1050       && frame_id_eq (get_frame_id (frame), a_frame_id))
1051     {
1052       /* Cool, all is fine.  */
1053       select_frame (frame);
1054       return;
1055     }
1056
1057   frame = frame_find_by_id (a_frame_id);
1058   if (frame != NULL)
1059     {
1060       /* Cool, refound it.  */
1061       select_frame (frame);
1062       return;
1063     }
1064
1065   /* Nothing else to do, the frame layout really changed.  Select the
1066      innermost stack frame.  */
1067   select_frame (get_current_frame ());
1068
1069   /* Warn the user.  */
1070   if (frame_level > 0 && !ui_out_is_mi_like_p (uiout))
1071     {
1072       warning (_("Couldn't restore frame #%d in "
1073                  "current thread, at reparsed frame #0\n"),
1074                frame_level);
1075       /* For MI, we should probably have a notification about
1076          current frame change.  But this error is not very
1077          likely, so don't bother for now.  */
1078       print_stack_frame (get_selected_frame (NULL), 1, SRC_LINE);
1079     }
1080 }
1081
1082 struct current_thread_cleanup
1083 {
1084   ptid_t inferior_ptid;
1085   struct frame_id selected_frame_id;
1086   int selected_frame_level;
1087   int was_stopped;
1088   int inf_id;
1089 };
1090
1091 static void
1092 do_restore_current_thread_cleanup (void *arg)
1093 {
1094   struct thread_info *tp;
1095   struct current_thread_cleanup *old = arg;
1096
1097   tp = find_thread_ptid (old->inferior_ptid);
1098
1099   /* If the previously selected thread belonged to a process that has
1100      in the mean time been deleted (due to normal exit, detach, etc.),
1101      then don't revert back to it, but instead simply drop back to no
1102      thread selected.  */
1103   if (tp
1104       && find_inferior_pid (ptid_get_pid (tp->ptid)) != NULL)
1105     restore_current_thread (old->inferior_ptid);
1106   else
1107     {
1108       restore_current_thread (null_ptid);
1109       set_current_inferior (find_inferior_id (old->inf_id));
1110     }
1111
1112   /* The running state of the originally selected thread may have
1113      changed, so we have to recheck it here.  */
1114   if (!ptid_equal (inferior_ptid, null_ptid)
1115       && old->was_stopped
1116       && is_stopped (inferior_ptid)
1117       && target_has_registers
1118       && target_has_stack
1119       && target_has_memory)
1120     restore_selected_frame (old->selected_frame_id,
1121                             old->selected_frame_level);
1122 }
1123
1124 static void
1125 restore_current_thread_cleanup_dtor (void *arg)
1126 {
1127   struct current_thread_cleanup *old = arg;
1128   struct thread_info *tp;
1129
1130   tp = find_thread_ptid (old->inferior_ptid);
1131   if (tp)
1132     tp->refcount--;
1133   xfree (old);
1134 }
1135
1136 struct cleanup *
1137 make_cleanup_restore_current_thread (void)
1138 {
1139   struct thread_info *tp;
1140   struct frame_info *frame;
1141   struct current_thread_cleanup *old;
1142
1143   old = xmalloc (sizeof (struct current_thread_cleanup));
1144   old->inferior_ptid = inferior_ptid;
1145   old->inf_id = current_inferior ()->num;
1146
1147   if (!ptid_equal (inferior_ptid, null_ptid))
1148     {
1149       old->was_stopped = is_stopped (inferior_ptid);
1150       if (old->was_stopped
1151           && target_has_registers
1152           && target_has_stack
1153           && target_has_memory)
1154         frame = get_selected_frame (NULL);
1155       else
1156         frame = NULL;
1157
1158       old->selected_frame_id = get_frame_id (frame);
1159       old->selected_frame_level = frame_relative_level (frame);
1160
1161       tp = find_thread_ptid (inferior_ptid);
1162       if (tp)
1163         tp->refcount++;
1164     }
1165
1166   return make_cleanup_dtor (do_restore_current_thread_cleanup, old,
1167                             restore_current_thread_cleanup_dtor);
1168 }
1169
1170 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
1171    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
1172    of two numbers seperated by a hyphen.  Examples:
1173
1174    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
1175    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
1176    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads.  */
1177
1178 static void
1179 thread_apply_all_command (char *cmd, int from_tty)
1180 {
1181   struct thread_info *tp;
1182   struct cleanup *old_chain;
1183   char *saved_cmd;
1184
1185   if (cmd == NULL || *cmd == '\000')
1186     error (_("Please specify a command following the thread ID list"));
1187
1188   update_thread_list ();
1189
1190   old_chain = make_cleanup_restore_current_thread ();
1191
1192   /* Save a copy of the command in case it is clobbered by
1193      execute_command.  */
1194   saved_cmd = xstrdup (cmd);
1195   make_cleanup (xfree, saved_cmd);
1196   for (tp = thread_list; tp; tp = tp->next)
1197     if (thread_alive (tp))
1198       {
1199         switch_to_thread (tp->ptid);
1200
1201         printf_filtered (_("\nThread %d (%s):\n"),
1202                          tp->num, target_pid_to_str (inferior_ptid));
1203         execute_command (cmd, from_tty);
1204         strcpy (cmd, saved_cmd);        /* Restore exact command used
1205                                            previously.  */
1206       }
1207
1208   do_cleanups (old_chain);
1209 }
1210
1211 static void
1212 thread_apply_command (char *tidlist, int from_tty)
1213 {
1214   char *cmd;
1215   struct cleanup *old_chain;
1216   char *saved_cmd;
1217
1218   if (tidlist == NULL || *tidlist == '\000')
1219     error (_("Please specify a thread ID list"));
1220
1221   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
1222
1223   if (*cmd == '\000')
1224     error (_("Please specify a command following the thread ID list"));
1225
1226   /* Save a copy of the command in case it is clobbered by
1227      execute_command.  */
1228   saved_cmd = xstrdup (cmd);
1229   old_chain = make_cleanup (xfree, saved_cmd);
1230   while (tidlist < cmd)
1231     {
1232       struct thread_info *tp;
1233       int start;
1234       char *p = tidlist;
1235
1236       start = get_number_or_range (&tidlist);
1237
1238       make_cleanup_restore_current_thread ();
1239
1240       tp = find_thread_id (start);
1241
1242       if (!tp)
1243         warning (_("Unknown thread %d."), start);
1244       else if (!thread_alive (tp))
1245         warning (_("Thread %d has terminated."), start);
1246       else
1247         {
1248           switch_to_thread (tp->ptid);
1249
1250           printf_filtered (_("\nThread %d (%s):\n"), tp->num,
1251                            target_pid_to_str (inferior_ptid));
1252           execute_command (cmd, from_tty);
1253
1254           /* Restore exact command used previously.  */
1255           strcpy (cmd, saved_cmd);
1256         }
1257     }
1258
1259   do_cleanups (old_chain);
1260 }
1261
1262 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
1263    if prefix of arg is `apply'.  */
1264
1265 static void
1266 thread_command (char *tidstr, int from_tty)
1267 {
1268   if (!tidstr)
1269     {
1270       if (ptid_equal (inferior_ptid, null_ptid))
1271         error (_("No thread selected"));
1272
1273       if (target_has_stack)
1274         {
1275           if (is_exited (inferior_ptid))
1276             printf_filtered (_("[Current thread is %d (%s) (exited)]\n"),
1277                              pid_to_thread_id (inferior_ptid),
1278                              target_pid_to_str (inferior_ptid));
1279           else
1280             printf_filtered (_("[Current thread is %d (%s)]\n"),
1281                              pid_to_thread_id (inferior_ptid),
1282                              target_pid_to_str (inferior_ptid));
1283         }
1284       else
1285         error (_("No stack."));
1286       return;
1287     }
1288
1289   gdb_thread_select (uiout, tidstr, NULL);
1290 }
1291
1292 /* Implementation of `thread name'.  */
1293
1294 static void
1295 thread_name_command (char *arg, int from_tty)
1296 {
1297   struct thread_info *info;
1298
1299   if (ptid_equal (inferior_ptid, null_ptid))
1300     error (_("No thread selected"));
1301
1302   while (arg && isspace (*arg))
1303     ++arg;
1304
1305   info = inferior_thread ();
1306   xfree (info->name);
1307   info->name = arg ? xstrdup (arg) : NULL;
1308 }
1309
1310 /* Find thread ids with a name, target pid, or extra info matching ARG.  */
1311
1312 static void
1313 thread_find_command (char *arg, int from_tty)
1314 {
1315   struct thread_info *tp;
1316   char *tmp;
1317   unsigned long match = 0;
1318
1319   if (arg == NULL || *arg == '\0')
1320     error (_("Command requires an argument."));
1321
1322   tmp = re_comp (arg);
1323   if (tmp != 0)
1324     error (_("Invalid regexp (%s): %s"), tmp, arg);
1325
1326   update_thread_list ();
1327   for (tp = thread_list; tp; tp = tp->next)
1328     {
1329       if (tp->name != NULL && re_exec (tp->name))
1330         {
1331           printf_filtered (_("Thread %d has name '%s'\n"),
1332                            tp->num, tp->name);
1333           match++;
1334         }
1335
1336       tmp = target_thread_name (tp);
1337       if (tmp != NULL && re_exec (tmp))
1338         {
1339           printf_filtered (_("Thread %d has target name '%s'\n"),
1340                            tp->num, tmp);
1341           match++;
1342         }
1343
1344       tmp = target_pid_to_str (tp->ptid);
1345       if (tmp != NULL && re_exec (tmp))
1346         {
1347           printf_filtered (_("Thread %d has target id '%s'\n"),
1348                            tp->num, tmp);
1349           match++;
1350         }
1351
1352       tmp = target_extra_thread_info (tp);
1353       if (tmp != NULL && re_exec (tmp))
1354         {
1355           printf_filtered (_("Thread %d has extra info '%s'\n"),
1356                            tp->num, tmp);
1357           match++;
1358         }
1359     }
1360   if (!match)
1361     printf_filtered (_("No threads match '%s'\n"), arg);
1362 }
1363
1364 /* Print notices when new threads are attached and detached.  */
1365 int print_thread_events = 1;
1366 static void
1367 show_print_thread_events (struct ui_file *file, int from_tty,
1368                           struct cmd_list_element *c, const char *value)
1369 {
1370   fprintf_filtered (file,
1371                     _("Printing of thread events is %s.\n"),
1372                     value);
1373 }
1374
1375 static int
1376 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
1377 {
1378   int num;
1379   struct thread_info *tp;
1380
1381   num = value_as_long (parse_and_eval (tidstr));
1382
1383   tp = find_thread_id (num);
1384
1385   if (!tp)
1386     error (_("Thread ID %d not known."), num);
1387
1388   if (!thread_alive (tp))
1389     error (_("Thread ID %d has terminated."), num);
1390
1391   switch_to_thread (tp->ptid);
1392
1393   annotate_thread_changed ();
1394
1395   ui_out_text (uiout, "[Switching to thread ");
1396   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
1397   ui_out_text (uiout, " (");
1398   ui_out_text (uiout, target_pid_to_str (inferior_ptid));
1399   ui_out_text (uiout, ")]");
1400
1401   /* Note that we can't reach this with an exited thread, due to the
1402      thread_alive check above.  */
1403   if (tp->state_ == THREAD_RUNNING)
1404     ui_out_text (uiout, "(running)\n");
1405   else
1406     {
1407       ui_out_text (uiout, "\n");
1408       print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
1409     }
1410
1411   /* Since the current thread may have changed, see if there is any
1412      exited thread we can now delete.  */
1413   prune_threads ();
1414
1415   return GDB_RC_OK;
1416 }
1417
1418 enum gdb_rc
1419 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
1420 {
1421   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
1422                                  error_message, RETURN_MASK_ALL) < 0)
1423     return GDB_RC_FAIL;
1424   return GDB_RC_OK;
1425 }
1426
1427 void
1428 update_thread_list (void)
1429 {
1430   prune_threads ();
1431   target_find_new_threads ();
1432 }
1433
1434 /* Return a new value for the selected thread's id.  Return a value of 0 if
1435    no thread is selected, or no threads exist.  */
1436
1437 static struct value *
1438 thread_id_make_value (struct gdbarch *gdbarch, struct internalvar *var)
1439 {
1440   struct thread_info *tp = find_thread_ptid (inferior_ptid);
1441
1442   return value_from_longest (builtin_type (gdbarch)->builtin_int,
1443                              (tp ? tp->num : 0));
1444 }
1445
1446 /* Commands with a prefix of `thread'.  */
1447 struct cmd_list_element *thread_cmd_list = NULL;
1448
1449 void
1450 _initialize_thread (void)
1451 {
1452   static struct cmd_list_element *thread_apply_list = NULL;
1453
1454   add_info ("threads", info_threads_command,
1455             _("Display currently known threads.\n\
1456 Usage: info threads [ID]...\n\
1457 Optional arguments are thread IDs with spaces between.\n\
1458 If no arguments, all threads are displayed."));
1459
1460   add_prefix_cmd ("thread", class_run, thread_command, _("\
1461 Use this command to switch between threads.\n\
1462 The new thread ID must be currently known."),
1463                   &thread_cmd_list, "thread ", 1, &cmdlist);
1464
1465   add_prefix_cmd ("apply", class_run, thread_apply_command,
1466                   _("Apply a command to a list of threads."),
1467                   &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
1468
1469   add_cmd ("all", class_run, thread_apply_all_command,
1470            _("Apply a command to all threads."), &thread_apply_list);
1471
1472   add_cmd ("name", class_run, thread_name_command,
1473            _("Set the current thread's name.\n\
1474 Usage: thread name [NAME]\n\
1475 If NAME is not given, then any existing name is removed."), &thread_cmd_list);
1476
1477   add_cmd ("find", class_run, thread_find_command, _("\
1478 Find threads that match a regular expression.\n\
1479 Usage: thread find REGEXP\n\
1480 Will display thread ids whose name, target ID, or extra info matches REGEXP."),
1481            &thread_cmd_list);
1482
1483   if (!xdb_commands)
1484     add_com_alias ("t", "thread", class_run, 1);
1485
1486   add_setshow_boolean_cmd ("thread-events", no_class,
1487          &print_thread_events, _("\
1488 Set printing of thread events (such as thread start and exit)."), _("\
1489 Show printing of thread events (such as thread start and exit)."), NULL,
1490          NULL,
1491          show_print_thread_events,
1492          &setprintlist, &showprintlist);
1493
1494   create_internalvar_type_lazy ("_thread", thread_id_make_value);
1495 }