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
  44 /* Definition of struct thread_info exported to gdbthread.h */
  45
  46 /* Prototypes for exported functions. */
  47
  48 void _initialize_thread (void);
  49
  50 /* Prototypes for local functions. */
  51
  52 static struct thread_info *thread_list = NULL;
  53 static int highest_thread_num;
  54
  55 static struct thread_info *find_thread_id (int 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 void
  66 delete_step_resume_breakpoint (void *arg)
  67 {
  68   struct breakpoint **breakpointp = (struct breakpoint **) arg;
  69   struct thread_info *tp;
  70
  71   if (*breakpointp != NULL)
  72     {
  73       delete_breakpoint (*breakpointp);
  74       for (tp = thread_list; tp; tp = tp->next)
  75         if (tp->step_resume_breakpoint == *breakpointp)
  76           tp->step_resume_breakpoint = NULL;
  77
  78       *breakpointp = NULL;
  79     }
  80 }
  81
  82 static void
  83 free_thread (struct thread_info *tp)
  84 {
  85   /* NOTE: this will take care of any left-over step_resume breakpoints,
  86      but not any user-specified thread-specific breakpoints.  We can not
  87      delete the breakpoint straight-off, because the inferior might not
  88      be stopped at the moment.  */
  89   if (tp->step_resume_breakpoint)
  90     tp->step_resume_breakpoint->disposition = disp_del_at_next_stop;
  91
  92   /* FIXME: do I ever need to call the back-end to give it a
  93      chance at this private data before deleting the thread?  */
  94   if (tp->private)
  95     xfree (tp->private);
  96
  97   xfree (tp);
  98 }
  99
 100 void
 101 init_thread_list (void)
 102 {
 103   struct thread_info *tp, *tpnext;
 104
 105   highest_thread_num = 0;
 106   if (!thread_list)
 107     return;
 108
 109   for (tp = thread_list; tp; tp = tpnext)
 110     {
 111       tpnext = tp->next;
 112       free_thread (tp);
 113     }
 114
 115   thread_list = NULL;
 116 }
 117
 118 struct thread_info *
 119 add_thread_silent (ptid_t ptid)
 120 {
 121   struct thread_info *tp;
 122
 123   tp = (struct thread_info *) xmalloc (sizeof (*tp));
 124   memset (tp, 0, sizeof (*tp));
 125   tp->ptid = ptid;
 126   tp->num = ++highest_thread_num;
 127   tp->next = thread_list;
 128   thread_list = tp;
 129
 130   observer_notify_new_thread (tp);
 131
 132   return tp;
 133 }
 134
 135 struct thread_info *
 136 add_thread_with_info (ptid_t ptid, struct private_thread_info *private)
 137 {
 138   struct thread_info *result = add_thread_silent (ptid);
 139
 140   result->private = private;
 141
 142   if (print_thread_events)
 143     printf_unfiltered (_("[New %s]\n"), target_pid_to_str (ptid));
 144
 145   return result;
 146 }
 147
 148 struct thread_info *
 149 add_thread (ptid_t ptid)
 150 {
 151   return add_thread_with_info (ptid, NULL);
 152 }
 153
 154 void
 155 delete_thread (ptid_t ptid)
 156 {
 157   struct thread_info *tp, *tpprev;
 158
 159   tpprev = NULL;
 160
 161   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 162     if (ptid_equal (tp->ptid, ptid))
 163       break;
 164
 165   if (!tp)
 166     return;
 167
 168   if (tpprev)
 169     tpprev->next = tp->next;
 170   else
 171     thread_list = tp->next;
 172
 173   observer_notify_thread_exit (tp);
 174
 175   free_thread (tp);
 176 }
 177
 178 static struct thread_info *
 179 find_thread_id (int num)
 180 {
 181   struct thread_info *tp;
 182
 183   for (tp = thread_list; tp; tp = tp->next)
 184     if (tp->num == num)
 185       return tp;
 186
 187   return NULL;
 188 }
 189
 190 /* Find a thread_info by matching PTID.  */
 191 struct thread_info *
 192 find_thread_pid (ptid_t ptid)
 193 {
 194   struct thread_info *tp;
 195
 196   for (tp = thread_list; tp; tp = tp->next)
 197     if (ptid_equal (tp->ptid, ptid))
 198       return tp;
 199
 200   return NULL;
 201 }
 202
 203 /*
 204  * Thread iterator function.
 205  *
 206  * Calls a callback function once for each thread, so long as
 207  * the callback function returns false.  If the callback function
 208  * returns true, the iteration will end and the current thread
 209  * will be returned.  This can be useful for implementing a
 210  * search for a thread with arbitrary attributes, or for applying
 211  * some operation to every thread.
 212  *
 213  * FIXME: some of the existing functionality, such as
 214  * "Thread apply all", might be rewritten using this functionality.
 215  */
 216
 217 struct thread_info *
 218 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 219                       void *data)
 220 {
 221   struct thread_info *tp;
 222
 223   for (tp = thread_list; tp; tp = tp->next)
 224     if ((*callback) (tp, data))
 225       return tp;
 226
 227   return NULL;
 228 }
 229
 230 int
 231 valid_thread_id (int num)
 232 {
 233   struct thread_info *tp;
 234
 235   for (tp = thread_list; tp; tp = tp->next)
 236     if (tp->num == num)
 237       return 1;
 238
 239   return 0;
 240 }
 241
 242 int
 243 pid_to_thread_id (ptid_t ptid)
 244 {
 245   struct thread_info *tp;
 246
 247   for (tp = thread_list; tp; tp = tp->next)
 248     if (ptid_equal (tp->ptid, ptid))
 249       return tp->num;
 250
 251   return 0;
 252 }
 253
 254 ptid_t
 255 thread_id_to_pid (int num)
 256 {
 257   struct thread_info *thread = find_thread_id (num);
 258   if (thread)
 259     return thread->ptid;
 260   else
 261     return pid_to_ptid (-1);
 262 }
 263
 264 int
 265 in_thread_list (ptid_t ptid)
 266 {
 267   struct thread_info *tp;
 268
 269   for (tp = thread_list; tp; tp = tp->next)
 270     if (ptid_equal (tp->ptid, ptid))
 271       return 1;
 272
 273   return 0;                     /* Never heard of 'im */
 274 }
 275
 276 /* Print a list of thread ids currently known, and the total number of
 277    threads. To be used from within catch_errors. */
 278 static int
 279 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 280 {
 281   struct thread_info *tp;
 282   int num = 0;
 283   struct cleanup *cleanup_chain;
 284
 285   prune_threads ();
 286   target_find_new_threads ();
 287
 288   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 289
 290   for (tp = thread_list; tp; tp = tp->next)
 291     {
 292       num++;
 293       ui_out_field_int (uiout, "thread-id", tp->num);
 294     }
 295
 296   do_cleanups (cleanup_chain);
 297   ui_out_field_int (uiout, "number-of-threads", num);
 298   return GDB_RC_OK;
 299 }
 300
 301 /* Official gdblib interface function to get a list of thread ids and
 302    the total number. */
 303 enum gdb_rc
 304 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 305 {
 306   if (catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 307                                  error_message, RETURN_MASK_ALL) < 0)
 308     return GDB_RC_FAIL;
 309   return GDB_RC_OK;
 310 }
 311
 312 /* Load infrun state for the thread PID.  */
 313
 314 void
 315 load_infrun_state (ptid_t ptid,
 316                    CORE_ADDR *prev_pc,
 317                    int *trap_expected,
 318                    struct breakpoint **step_resume_breakpoint,
 319                    CORE_ADDR *step_range_start,
 320                    CORE_ADDR *step_range_end,
 321                    struct frame_id *step_frame_id,
 322                    int *stepping_over_breakpoint,
 323                    int *stepping_through_solib_after_catch,
 324                    bpstat *stepping_through_solib_catchpoints,
 325                    int *current_line,
 326                    struct symtab **current_symtab)
 327 {
 328   struct thread_info *tp;
 329
 330   /* If we can't find the thread, then we're debugging a single threaded
 331      process.  No need to do anything in that case.  */
 332   tp = find_thread_id (pid_to_thread_id (ptid));
 333   if (tp == NULL)
 334     return;
 335
 336   *prev_pc = tp->prev_pc;
 337   *trap_expected = tp->trap_expected;
 338   *step_resume_breakpoint = tp->step_resume_breakpoint;
 339   *step_range_start = tp->step_range_start;
 340   *step_range_end = tp->step_range_end;
 341   *step_frame_id = tp->step_frame_id;
 342   *stepping_over_breakpoint = tp->stepping_over_breakpoint;
 343   *stepping_through_solib_after_catch =
 344     tp->stepping_through_solib_after_catch;
 345   *stepping_through_solib_catchpoints =
 346     tp->stepping_through_solib_catchpoints;
 347   *current_line = tp->current_line;
 348   *current_symtab = tp->current_symtab;
 349 }
 350
 351 /* Save infrun state for the thread PID.  */
 352
 353 void
 354 save_infrun_state (ptid_t ptid,
 355                    CORE_ADDR prev_pc,
 356                    int trap_expected,
 357                    struct breakpoint *step_resume_breakpoint,
 358                    CORE_ADDR step_range_start,
 359                    CORE_ADDR step_range_end,
 360                    const struct frame_id *step_frame_id,
 361                    int stepping_over_breakpoint,
 362                    int stepping_through_solib_after_catch,
 363                    bpstat stepping_through_solib_catchpoints,
 364                    int current_line,
 365                    struct symtab *current_symtab)
 366 {
 367   struct thread_info *tp;
 368
 369   /* If we can't find the thread, then we're debugging a single-threaded
 370      process.  Nothing to do in that case.  */
 371   tp = find_thread_id (pid_to_thread_id (ptid));
 372   if (tp == NULL)
 373     return;
 374
 375   tp->prev_pc = prev_pc;
 376   tp->trap_expected = trap_expected;
 377   tp->step_resume_breakpoint = step_resume_breakpoint;
 378   tp->step_range_start = step_range_start;
 379   tp->step_range_end = step_range_end;
 380   tp->step_frame_id = (*step_frame_id);
 381   tp->stepping_over_breakpoint = stepping_over_breakpoint;
 382   tp->stepping_through_solib_after_catch = stepping_through_solib_after_catch;
 383   tp->stepping_through_solib_catchpoints = stepping_through_solib_catchpoints;
 384   tp->current_line = current_line;
 385   tp->current_symtab = current_symtab;
 386 }
 387
 388 /* Return true if TP is an active thread. */
 389 static int
 390 thread_alive (struct thread_info *tp)
 391 {
 392   if (PIDGET (tp->ptid) == -1)
 393     return 0;
 394   if (!target_thread_alive (tp->ptid))
 395     {
 396       tp->ptid = pid_to_ptid (-1);      /* Mark it as dead */
 397       return 0;
 398     }
 399   return 1;
 400 }
 401
 402 static void
 403 prune_threads (void)
 404 {
 405   struct thread_info *tp, *next;
 406
 407   for (tp = thread_list; tp; tp = next)
 408     {
 409       next = tp->next;
 410       if (!thread_alive (tp))
 411         delete_thread (tp->ptid);
 412     }
 413 }
 414
 415 /* Prints the list of threads and their details on UIOUT.
 416    This is a version of 'info_thread_command' suitable for
 417    use from MI.
 418    If REQESTED_THREAD is not -1, it's the GDB id of the thread
 419    that should be printed.  Otherwise, all threads are
 420    printed.  */
 421 void
 422 print_thread_info (struct ui_out *uiout, int requested_thread)
 423 {
 424   struct thread_info *tp;
 425   ptid_t current_ptid;
 426   struct frame_info *cur_frame;
 427   struct cleanup *old_chain;
 428   struct frame_id saved_frame_id;
 429   char *extra_info;
 430   int current_thread = -1;
 431
 432   /* Backup current thread and selected frame.  */
 433   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 434   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 435
 436   make_cleanup_ui_out_list_begin_end (uiout, "threads");
 437
 438   prune_threads ();
 439   target_find_new_threads ();
 440   current_ptid = inferior_ptid;
 441   for (tp = thread_list; tp; tp = tp->next)
 442     {
 443       struct cleanup *chain2;
 444
 445       if (requested_thread != -1 && tp->num != requested_thread)
 446         continue;
 447
 448       chain2 = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 449
 450       if (ptid_equal (tp->ptid, current_ptid))
 451         {
 452           current_thread = tp->num;
 453           ui_out_text (uiout, "* ");
 454         }
 455       else
 456         ui_out_text (uiout, "  ");
 457
 458       ui_out_field_int (uiout, "id", tp->num);
 459       ui_out_text (uiout, " ");
 460       ui_out_field_string (uiout, "target-id", target_tid_to_str (tp->ptid));
 461
 462       extra_info = target_extra_thread_info (tp);
 463       if (extra_info)
 464         {
 465           ui_out_text (uiout, " (");
 466           ui_out_field_string (uiout, "details", extra_info);
 467           ui_out_text (uiout, ")");
 468         }
 469       ui_out_text (uiout, "  ");
 470       /* That switch put us at the top of the stack (leaf frame).  */
 471       switch_to_thread (tp->ptid);
 472       print_stack_frame (get_selected_frame (NULL),
 473                          /* For MI output, print frame level.  */
 474                          ui_out_is_mi_like_p (uiout),
 475                          LOCATION);
 476
 477       do_cleanups (chain2);
 478     }
 479
 480   /* Restores the current thread and the frame selected before
 481      the "info threads" command.  */
 482   do_cleanups (old_chain);
 483
 484   if (requested_thread == -1)
 485     {
 486       gdb_assert (current_thread != -1 || !thread_list);
 487       if (current_thread != -1 && ui_out_is_mi_like_p (uiout))
 488         ui_out_field_int (uiout, "current-thread-id", current_thread);
 489     }
 490
 491   /*  If case we were not able to find the original frame, print the
 492       new selected frame.  */
 493   if (frame_find_by_id (saved_frame_id) == NULL)
 494     {
 495       warning (_("Couldn't restore frame in current thread, at frame 0"));
 496       /* For MI, we should probably have a notification about
 497          current frame change.  But this error is not very likely, so
 498          don't bother for now.  */
 499       if (!ui_out_is_mi_like_p (uiout))
 500         print_stack_frame (get_selected_frame (NULL), 0, LOCATION);
 501     }
 502 }
 503
 504
 505 /* Print information about currently known threads
 506
 507  * Note: this has the drawback that it _really_ switches
 508  *       threads, which frees the frame cache.  A no-side
 509  *       effects info-threads command would be nicer.
 510  */
 511
 512 static void
 513 info_threads_command (char *arg, int from_tty)
 514 {
 515   print_thread_info (uiout, -1);
 516 }
 517
 518 /* Switch from one thread to another. */
 519
 520 void
 521 switch_to_thread (ptid_t ptid)
 522 {
 523   if (ptid_equal (ptid, inferior_ptid))
 524     return;
 525
 526   inferior_ptid = ptid;
 527   reinit_frame_cache ();
 528   registers_changed ();
 529   stop_pc = read_pc ();
 530 }
 531
 532 static void
 533 restore_current_thread (ptid_t ptid)
 534 {
 535   if (!ptid_equal (ptid, inferior_ptid))
 536     {
 537       switch_to_thread (ptid);
 538     }
 539 }
 540
 541 static void
 542 restore_selected_frame (struct frame_id a_frame_id)
 543 {
 544   struct frame_info *selected_frame_info = NULL;
 545
 546   if (frame_id_eq (a_frame_id, null_frame_id))
 547     return;
 548
 549   if ((selected_frame_info = frame_find_by_id (a_frame_id)) != NULL)
 550     {
 551       select_frame (selected_frame_info);
 552     }
 553 }
 554
 555 struct current_thread_cleanup
 556 {
 557   ptid_t inferior_ptid;
 558   struct frame_id selected_frame_id;
 559 };
 560
 561 static void
 562 do_restore_current_thread_cleanup (void *arg)
 563 {
 564   struct current_thread_cleanup *old = arg;
 565   restore_current_thread (old->inferior_ptid);
 566   restore_selected_frame (old->selected_frame_id);
 567   xfree (old);
 568 }
 569
 570 struct cleanup *
 571 make_cleanup_restore_current_thread (ptid_t inferior_ptid,
 572                                      struct frame_id a_frame_id)
 573 {
 574   struct current_thread_cleanup *old
 575     = xmalloc (sizeof (struct current_thread_cleanup));
 576   old->inferior_ptid = inferior_ptid;
 577   old->selected_frame_id = a_frame_id;
 578   return make_cleanup (do_restore_current_thread_cleanup, old);
 579 }
 580
 581 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 582    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 583    of two numbers seperated by a hyphen.  Examples:
 584
 585    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 586    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 587    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 588  */
 589
 590 static void
 591 thread_apply_all_command (char *cmd, int from_tty)
 592 {
 593   struct thread_info *tp;
 594   struct cleanup *old_chain;
 595   struct cleanup *saved_cmd_cleanup_chain;
 596   char *saved_cmd;
 597   struct frame_id saved_frame_id;
 598   ptid_t current_ptid;
 599   int thread_has_changed = 0;
 600
 601   if (cmd == NULL || *cmd == '\000')
 602     error (_("Please specify a command following the thread ID list"));
 603
 604   current_ptid = inferior_ptid;
 605   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 606   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 607
 608   /* It is safe to update the thread list now, before
 609      traversing it for "thread apply all".  MVS */
 610   target_find_new_threads ();
 611
 612   /* Save a copy of the command in case it is clobbered by
 613      execute_command */
 614   saved_cmd = xstrdup (cmd);
 615   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 616   for (tp = thread_list; tp; tp = tp->next)
 617     if (thread_alive (tp))
 618       {
 619         switch_to_thread (tp->ptid);
 620         printf_filtered (_("\nThread %d (%s):\n"),
 621                          tp->num, target_tid_to_str (inferior_ptid));
 622         execute_command (cmd, from_tty);
 623         strcpy (cmd, saved_cmd);        /* Restore exact command used previously */
 624       }
 625
 626   if (!ptid_equal (current_ptid, inferior_ptid))
 627     thread_has_changed = 1;
 628
 629   do_cleanups (saved_cmd_cleanup_chain);
 630   do_cleanups (old_chain);
 631   /* Print stack frame only if we changed thread.  */
 632   if (thread_has_changed)
 633     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 634
 635 }
 636
 637 static void
 638 thread_apply_command (char *tidlist, int from_tty)
 639 {
 640   char *cmd;
 641   char *p;
 642   struct cleanup *old_chain;
 643   struct cleanup *saved_cmd_cleanup_chain;
 644   char *saved_cmd;
 645   struct frame_id saved_frame_id;
 646   ptid_t current_ptid;
 647   int thread_has_changed = 0;
 648
 649   if (tidlist == NULL || *tidlist == '\000')
 650     error (_("Please specify a thread ID list"));
 651
 652   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 653
 654   if (*cmd == '\000')
 655     error (_("Please specify a command following the thread ID list"));
 656
 657   current_ptid = inferior_ptid;
 658   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 659   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 660
 661   /* Save a copy of the command in case it is clobbered by
 662      execute_command */
 663   saved_cmd = xstrdup (cmd);
 664   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 665   while (tidlist < cmd)
 666     {
 667       struct thread_info *tp;
 668       int start, end;
 669
 670       start = strtol (tidlist, &p, 10);
 671       if (p == tidlist)
 672         error (_("Error parsing %s"), tidlist);
 673       tidlist = p;
 674
 675       while (*tidlist == ' ' || *tidlist == '\t')
 676         tidlist++;
 677
 678       if (*tidlist == '-')      /* Got a range of IDs? */
 679         {
 680           tidlist++;            /* Skip the - */
 681           end = strtol (tidlist, &p, 10);
 682           if (p == tidlist)
 683             error (_("Error parsing %s"), tidlist);
 684           tidlist = p;
 685
 686           while (*tidlist == ' ' || *tidlist == '\t')
 687             tidlist++;
 688         }
 689       else
 690         end = start;
 691
 692       for (; start <= end; start++)
 693         {
 694           tp = find_thread_id (start);
 695
 696           if (!tp)
 697             warning (_("Unknown thread %d."), start);
 698           else if (!thread_alive (tp))
 699             warning (_("Thread %d has terminated."), start);
 700           else
 701             {
 702               switch_to_thread (tp->ptid);
 703               printf_filtered (_("\nThread %d (%s):\n"), tp->num,
 704                                target_tid_to_str (inferior_ptid));
 705               execute_command (cmd, from_tty);
 706               strcpy (cmd, saved_cmd);  /* Restore exact command used previously */
 707             }
 708         }
 709     }
 710
 711   if (!ptid_equal (current_ptid, inferior_ptid))
 712     thread_has_changed = 1;
 713
 714   do_cleanups (saved_cmd_cleanup_chain);
 715   do_cleanups (old_chain);
 716   /* Print stack frame only if we changed thread.  */
 717   if (thread_has_changed)
 718     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 719 }
 720
 721 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
 722    if prefix of arg is `apply'.  */
 723
 724 static void
 725 thread_command (char *tidstr, int from_tty)
 726 {
 727   if (!tidstr)
 728     {
 729       /* Don't generate an error, just say which thread is current. */
 730       if (target_has_stack)
 731         printf_filtered (_("[Current thread is %d (%s)]\n"),
 732                          pid_to_thread_id (inferior_ptid),
 733                          target_tid_to_str (inferior_ptid));
 734       else
 735         error (_("No stack."));
 736       return;
 737     }
 738
 739   gdb_thread_select (uiout, tidstr, NULL);
 740 }
 741
 742 /* Print notices when new threads are attached and detached.  */
 743 int print_thread_events = 1;
 744 static void
 745 show_print_thread_events (struct ui_file *file, int from_tty,
 746                           struct cmd_list_element *c, const char *value)
 747 {
 748   fprintf_filtered (file, _("\
 749 Printing of thread events is %s.\n"),
 750                     value);
 751 }
 752
 753 static int
 754 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
 755 {
 756   int num;
 757   struct thread_info *tp;
 758
 759   num = value_as_long (parse_and_eval (tidstr));
 760
 761   tp = find_thread_id (num);
 762
 763   if (!tp)
 764     error (_("Thread ID %d not known."), num);
 765
 766   if (!thread_alive (tp))
 767     error (_("Thread ID %d has terminated."), num);
 768
 769   switch_to_thread (tp->ptid);
 770
 771   ui_out_text (uiout, "[Switching to thread ");
 772   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
 773   ui_out_text (uiout, " (");
 774   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
 775   ui_out_text (uiout, ")]");
 776
 777   print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
 778   return GDB_RC_OK;
 779 }
 780
 781 enum gdb_rc
 782 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
 783 {
 784   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
 785                                  error_message, RETURN_MASK_ALL) < 0)
 786     return GDB_RC_FAIL;
 787   return GDB_RC_OK;
 788 }
 789
 790 /* Commands with a prefix of `thread'.  */
 791 struct cmd_list_element *thread_cmd_list = NULL;
 792
 793 void
 794 _initialize_thread (void)
 795 {
 796   static struct cmd_list_element *thread_apply_list = NULL;
 797
 798   add_info ("threads", info_threads_command,
 799             _("IDs of currently known threads."));
 800
 801   add_prefix_cmd ("thread", class_run, thread_command, _("\
 802 Use this command to switch between threads.\n\
 803 The new thread ID must be currently known."),
 804                   &thread_cmd_list, "thread ", 1, &cmdlist);
 805
 806   add_prefix_cmd ("apply", class_run, thread_apply_command,
 807                   _("Apply a command to a list of threads."),
 808                   &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
 809
 810   add_cmd ("all", class_run, thread_apply_all_command,
 811            _("Apply a command to all threads."), &thread_apply_list);
 812
 813   if (!xdb_commands)
 814     add_com_alias ("t", "thread", class_run, 1);
 815
 816   add_setshow_boolean_cmd ("thread-events", no_class,
 817          &print_thread_events, _("\
 818 Set printing of thread events (such as thread start and exit)."), _("\
 819 Show printing of thread events (such as thread start and exit)."), NULL,
 820          NULL,
 821          show_print_thread_events,
 822          &setprintlist, &showprintlist);
 823 }