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   free_thread (tp);
 174 }
 175
 176 static struct thread_info *
 177 find_thread_id (int num)
 178 {
 179   struct thread_info *tp;
 180
 181   for (tp = thread_list; tp; tp = tp->next)
 182     if (tp->num == num)
 183       return tp;
 184
 185   return NULL;
 186 }
 187
 188 /* Find a thread_info by matching PTID.  */
 189 struct thread_info *
 190 find_thread_pid (ptid_t ptid)
 191 {
 192   struct thread_info *tp;
 193
 194   for (tp = thread_list; tp; tp = tp->next)
 195     if (ptid_equal (tp->ptid, ptid))
 196       return tp;
 197
 198   return NULL;
 199 }
 200
 201 /*
 202  * Thread iterator function.
 203  *
 204  * Calls a callback function once for each thread, so long as
 205  * the callback function returns false.  If the callback function
 206  * returns true, the iteration will end and the current thread
 207  * will be returned.  This can be useful for implementing a
 208  * search for a thread with arbitrary attributes, or for applying
 209  * some operation to every thread.
 210  *
 211  * FIXME: some of the existing functionality, such as
 212  * "Thread apply all", might be rewritten using this functionality.
 213  */
 214
 215 struct thread_info *
 216 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 217                       void *data)
 218 {
 219   struct thread_info *tp;
 220
 221   for (tp = thread_list; tp; tp = tp->next)
 222     if ((*callback) (tp, data))
 223       return tp;
 224
 225   return NULL;
 226 }
 227
 228 int
 229 valid_thread_id (int num)
 230 {
 231   struct thread_info *tp;
 232
 233   for (tp = thread_list; tp; tp = tp->next)
 234     if (tp->num == num)
 235       return 1;
 236
 237   return 0;
 238 }
 239
 240 int
 241 pid_to_thread_id (ptid_t ptid)
 242 {
 243   struct thread_info *tp;
 244
 245   for (tp = thread_list; tp; tp = tp->next)
 246     if (ptid_equal (tp->ptid, ptid))
 247       return tp->num;
 248
 249   return 0;
 250 }
 251
 252 ptid_t
 253 thread_id_to_pid (int num)
 254 {
 255   struct thread_info *thread = find_thread_id (num);
 256   if (thread)
 257     return thread->ptid;
 258   else
 259     return pid_to_ptid (-1);
 260 }
 261
 262 int
 263 in_thread_list (ptid_t ptid)
 264 {
 265   struct thread_info *tp;
 266
 267   for (tp = thread_list; tp; tp = tp->next)
 268     if (ptid_equal (tp->ptid, ptid))
 269       return 1;
 270
 271   return 0;                     /* Never heard of 'im */
 272 }
 273
 274 /* Print a list of thread ids currently known, and the total number of
 275    threads. To be used from within catch_errors. */
 276 static int
 277 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 278 {
 279   struct thread_info *tp;
 280   int num = 0;
 281   struct cleanup *cleanup_chain;
 282
 283   prune_threads ();
 284   target_find_new_threads ();
 285
 286   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 287
 288   for (tp = thread_list; tp; tp = tp->next)
 289     {
 290       num++;
 291       ui_out_field_int (uiout, "thread-id", tp->num);
 292     }
 293
 294   do_cleanups (cleanup_chain);
 295   ui_out_field_int (uiout, "number-of-threads", num);
 296   return GDB_RC_OK;
 297 }
 298
 299 /* Official gdblib interface function to get a list of thread ids and
 300    the total number. */
 301 enum gdb_rc
 302 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 303 {
 304   if (catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 305                                  error_message, RETURN_MASK_ALL) < 0)
 306     return GDB_RC_FAIL;
 307   return GDB_RC_OK;
 308 }
 309
 310 /* Load infrun state for the thread PID.  */
 311
 312 void
 313 load_infrun_state (ptid_t ptid,
 314                    CORE_ADDR *prev_pc,
 315                    int *trap_expected,
 316                    struct breakpoint **step_resume_breakpoint,
 317                    CORE_ADDR *step_range_start,
 318                    CORE_ADDR *step_range_end,
 319                    struct frame_id *step_frame_id,
 320                    int *handling_longjmp,
 321                    int *stepping_over_breakpoint,
 322                    int *stepping_through_solib_after_catch,
 323                    bpstat *stepping_through_solib_catchpoints,
 324                    int *current_line,
 325                    struct symtab **current_symtab)
 326 {
 327   struct thread_info *tp;
 328
 329   /* If we can't find the thread, then we're debugging a single threaded
 330      process.  No need to do anything in that case.  */
 331   tp = find_thread_id (pid_to_thread_id (ptid));
 332   if (tp == NULL)
 333     return;
 334
 335   *prev_pc = tp->prev_pc;
 336   *trap_expected = tp->trap_expected;
 337   *step_resume_breakpoint = tp->step_resume_breakpoint;
 338   *step_range_start = tp->step_range_start;
 339   *step_range_end = tp->step_range_end;
 340   *step_frame_id = tp->step_frame_id;
 341   *handling_longjmp = tp->handling_longjmp;
 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 handling_longjmp,
 362                    int stepping_over_breakpoint,
 363                    int stepping_through_solib_after_catch,
 364                    bpstat stepping_through_solib_catchpoints,
 365                    int current_line,
 366                    struct symtab *current_symtab)
 367 {
 368   struct thread_info *tp;
 369
 370   /* If we can't find the thread, then we're debugging a single-threaded
 371      process.  Nothing to do in that case.  */
 372   tp = find_thread_id (pid_to_thread_id (ptid));
 373   if (tp == NULL)
 374     return;
 375
 376   tp->prev_pc = prev_pc;
 377   tp->trap_expected = trap_expected;
 378   tp->step_resume_breakpoint = step_resume_breakpoint;
 379   tp->step_range_start = step_range_start;
 380   tp->step_range_end = step_range_end;
 381   tp->step_frame_id = (*step_frame_id);
 382   tp->handling_longjmp = handling_longjmp;
 383   tp->stepping_over_breakpoint = stepping_over_breakpoint;
 384   tp->stepping_through_solib_after_catch = stepping_through_solib_after_catch;
 385   tp->stepping_through_solib_catchpoints = stepping_through_solib_catchpoints;
 386   tp->current_line = current_line;
 387   tp->current_symtab = current_symtab;
 388 }
 389
 390 /* Return true if TP is an active thread. */
 391 static int
 392 thread_alive (struct thread_info *tp)
 393 {
 394   if (PIDGET (tp->ptid) == -1)
 395     return 0;
 396   if (!target_thread_alive (tp->ptid))
 397     {
 398       tp->ptid = pid_to_ptid (-1);      /* Mark it as dead */
 399       return 0;
 400     }
 401   return 1;
 402 }
 403
 404 static void
 405 prune_threads (void)
 406 {
 407   struct thread_info *tp, *next;
 408
 409   for (tp = thread_list; tp; tp = next)
 410     {
 411       next = tp->next;
 412       if (!thread_alive (tp))
 413         delete_thread (tp->ptid);
 414     }
 415 }
 416
 417 /* Prints the list of threads and their details on UIOUT.
 418    This is a version of 'info_thread_command' suitable for
 419    use from MI.
 420    If REQESTED_THREAD is not -1, it's the GDB id of the thread
 421    that should be printed.  Otherwise, all threads are
 422    printed.  */
 423 void
 424 print_thread_info (struct ui_out *uiout, int requested_thread)
 425 {
 426   struct thread_info *tp;
 427   ptid_t current_ptid;
 428   struct frame_info *cur_frame;
 429   struct cleanup *old_chain;
 430   struct frame_id saved_frame_id;
 431   char *extra_info;
 432   int current_thread = -1;
 433
 434   /* Backup current thread and selected frame.  */
 435   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 436   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 437
 438   make_cleanup_ui_out_list_begin_end (uiout, "threads");
 439
 440   prune_threads ();
 441   target_find_new_threads ();
 442   current_ptid = inferior_ptid;
 443   for (tp = thread_list; tp; tp = tp->next)
 444     {
 445       struct cleanup *chain2;
 446
 447       if (requested_thread != -1 && tp->num != requested_thread)
 448         continue;
 449
 450       chain2 = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 451
 452       if (ptid_equal (tp->ptid, current_ptid))
 453         {
 454           current_thread = tp->num;
 455           ui_out_text (uiout, "* ");
 456         }
 457       else
 458         ui_out_text (uiout, "  ");
 459
 460       ui_out_field_int (uiout, "id", tp->num);
 461       ui_out_text (uiout, " ");
 462       ui_out_field_string (uiout, "target-id", target_tid_to_str (tp->ptid));
 463
 464       extra_info = target_extra_thread_info (tp);
 465       if (extra_info)
 466         {
 467           ui_out_text (uiout, " (");
 468           ui_out_field_string (uiout, "details", extra_info);
 469           ui_out_text (uiout, ")");
 470         }
 471       ui_out_text (uiout, "  ");
 472       /* That switch put us at the top of the stack (leaf frame).  */
 473       switch_to_thread (tp->ptid);
 474       print_stack_frame (get_selected_frame (NULL),
 475                          /* For MI output, print frame level.  */
 476                          ui_out_is_mi_like_p (uiout),
 477                          LOCATION);
 478
 479       do_cleanups (chain2);
 480     }
 481
 482   /* Restores the current thread and the frame selected before
 483      the "info threads" command.  */
 484   do_cleanups (old_chain);
 485
 486   if (requested_thread == -1)
 487     {
 488       gdb_assert (current_thread != -1 || !thread_list);
 489       if (current_thread != -1 && ui_out_is_mi_like_p (uiout))
 490         ui_out_field_int (uiout, "current-thread-id", current_thread);
 491     }
 492
 493   /*  If case we were not able to find the original frame, print the
 494       new selected frame.  */
 495   if (frame_find_by_id (saved_frame_id) == NULL)
 496     {
 497       warning (_("Couldn't restore frame in current thread, at frame 0"));
 498       /* For MI, we should probably have a notification about
 499          current frame change.  But this error is not very likely, so
 500          don't bother for now.  */
 501       if (!ui_out_is_mi_like_p (uiout))
 502         print_stack_frame (get_selected_frame (NULL), 0, LOCATION);
 503     }
 504 }
 505
 506
 507 /* Print information about currently known threads
 508
 509  * Note: this has the drawback that it _really_ switches
 510  *       threads, which frees the frame cache.  A no-side
 511  *       effects info-threads command would be nicer.
 512  */
 513
 514 static void
 515 info_threads_command (char *arg, int from_tty)
 516 {
 517   print_thread_info (uiout, -1);
 518 }
 519
 520 /* Switch from one thread to another. */
 521
 522 void
 523 switch_to_thread (ptid_t ptid)
 524 {
 525   if (ptid_equal (ptid, inferior_ptid))
 526     return;
 527
 528   inferior_ptid = ptid;
 529   reinit_frame_cache ();
 530   registers_changed ();
 531   stop_pc = read_pc ();
 532 }
 533
 534 static void
 535 restore_current_thread (ptid_t ptid)
 536 {
 537   if (!ptid_equal (ptid, inferior_ptid))
 538     {
 539       switch_to_thread (ptid);
 540     }
 541 }
 542
 543 static void
 544 restore_selected_frame (struct frame_id a_frame_id)
 545 {
 546   struct frame_info *selected_frame_info = NULL;
 547
 548   if (frame_id_eq (a_frame_id, null_frame_id))
 549     return;
 550
 551   if ((selected_frame_info = frame_find_by_id (a_frame_id)) != NULL)
 552     {
 553       select_frame (selected_frame_info);
 554     }
 555 }
 556
 557 struct current_thread_cleanup
 558 {
 559   ptid_t inferior_ptid;
 560   struct frame_id selected_frame_id;
 561 };
 562
 563 static void
 564 do_restore_current_thread_cleanup (void *arg)
 565 {
 566   struct current_thread_cleanup *old = arg;
 567   restore_current_thread (old->inferior_ptid);
 568   restore_selected_frame (old->selected_frame_id);
 569   xfree (old);
 570 }
 571
 572 struct cleanup *
 573 make_cleanup_restore_current_thread (ptid_t inferior_ptid,
 574                                      struct frame_id a_frame_id)
 575 {
 576   struct current_thread_cleanup *old
 577     = xmalloc (sizeof (struct current_thread_cleanup));
 578   old->inferior_ptid = inferior_ptid;
 579   old->selected_frame_id = a_frame_id;
 580   return make_cleanup (do_restore_current_thread_cleanup, old);
 581 }
 582
 583 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 584    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 585    of two numbers seperated by a hyphen.  Examples:
 586
 587    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 588    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 589    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 590  */
 591
 592 static void
 593 thread_apply_all_command (char *cmd, int from_tty)
 594 {
 595   struct thread_info *tp;
 596   struct cleanup *old_chain;
 597   struct cleanup *saved_cmd_cleanup_chain;
 598   char *saved_cmd;
 599   struct frame_id saved_frame_id;
 600   ptid_t current_ptid;
 601   int thread_has_changed = 0;
 602
 603   if (cmd == NULL || *cmd == '\000')
 604     error (_("Please specify a command following the thread ID list"));
 605
 606   current_ptid = inferior_ptid;
 607   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 608   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 609
 610   /* It is safe to update the thread list now, before
 611      traversing it for "thread apply all".  MVS */
 612   target_find_new_threads ();
 613
 614   /* Save a copy of the command in case it is clobbered by
 615      execute_command */
 616   saved_cmd = xstrdup (cmd);
 617   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 618   for (tp = thread_list; tp; tp = tp->next)
 619     if (thread_alive (tp))
 620       {
 621         switch_to_thread (tp->ptid);
 622         printf_filtered (_("\nThread %d (%s):\n"),
 623                          tp->num, target_tid_to_str (inferior_ptid));
 624         execute_command (cmd, from_tty);
 625         strcpy (cmd, saved_cmd);        /* Restore exact command used previously */
 626       }
 627
 628   if (!ptid_equal (current_ptid, inferior_ptid))
 629     thread_has_changed = 1;
 630
 631   do_cleanups (saved_cmd_cleanup_chain);
 632   do_cleanups (old_chain);
 633   /* Print stack frame only if we changed thread.  */
 634   if (thread_has_changed)
 635     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 636
 637 }
 638
 639 static void
 640 thread_apply_command (char *tidlist, int from_tty)
 641 {
 642   char *cmd;
 643   char *p;
 644   struct cleanup *old_chain;
 645   struct cleanup *saved_cmd_cleanup_chain;
 646   char *saved_cmd;
 647   struct frame_id saved_frame_id;
 648   ptid_t current_ptid;
 649   int thread_has_changed = 0;
 650
 651   if (tidlist == NULL || *tidlist == '\000')
 652     error (_("Please specify a thread ID list"));
 653
 654   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 655
 656   if (*cmd == '\000')
 657     error (_("Please specify a command following the thread ID list"));
 658
 659   current_ptid = inferior_ptid;
 660   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 661   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 662
 663   /* Save a copy of the command in case it is clobbered by
 664      execute_command */
 665   saved_cmd = xstrdup (cmd);
 666   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 667   while (tidlist < cmd)
 668     {
 669       struct thread_info *tp;
 670       int start, end;
 671
 672       start = strtol (tidlist, &p, 10);
 673       if (p == tidlist)
 674         error (_("Error parsing %s"), tidlist);
 675       tidlist = p;
 676
 677       while (*tidlist == ' ' || *tidlist == '\t')
 678         tidlist++;
 679
 680       if (*tidlist == '-')      /* Got a range of IDs? */
 681         {
 682           tidlist++;            /* Skip the - */
 683           end = strtol (tidlist, &p, 10);
 684           if (p == tidlist)
 685             error (_("Error parsing %s"), tidlist);
 686           tidlist = p;
 687
 688           while (*tidlist == ' ' || *tidlist == '\t')
 689             tidlist++;
 690         }
 691       else
 692         end = start;
 693
 694       for (; start <= end; start++)
 695         {
 696           tp = find_thread_id (start);
 697
 698           if (!tp)
 699             warning (_("Unknown thread %d."), start);
 700           else if (!thread_alive (tp))
 701             warning (_("Thread %d has terminated."), start);
 702           else
 703             {
 704               switch_to_thread (tp->ptid);
 705               printf_filtered (_("\nThread %d (%s):\n"), tp->num,
 706                                target_tid_to_str (inferior_ptid));
 707               execute_command (cmd, from_tty);
 708               strcpy (cmd, saved_cmd);  /* Restore exact command used previously */
 709             }
 710         }
 711     }
 712
 713   if (!ptid_equal (current_ptid, inferior_ptid))
 714     thread_has_changed = 1;
 715
 716   do_cleanups (saved_cmd_cleanup_chain);
 717   do_cleanups (old_chain);
 718   /* Print stack frame only if we changed thread.  */
 719   if (thread_has_changed)
 720     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 721 }
 722
 723 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
 724    if prefix of arg is `apply'.  */
 725
 726 static void
 727 thread_command (char *tidstr, int from_tty)
 728 {
 729   if (!tidstr)
 730     {
 731       /* Don't generate an error, just say which thread is current. */
 732       if (target_has_stack)
 733         printf_filtered (_("[Current thread is %d (%s)]\n"),
 734                          pid_to_thread_id (inferior_ptid),
 735                          target_tid_to_str (inferior_ptid));
 736       else
 737         error (_("No stack."));
 738       return;
 739     }
 740
 741   gdb_thread_select (uiout, tidstr, NULL);
 742 }
 743
 744 /* Print notices when new threads are attached and detached.  */
 745 int print_thread_events = 1;
 746 static void
 747 show_print_thread_events (struct ui_file *file, int from_tty,
 748                           struct cmd_list_element *c, const char *value)
 749 {
 750   fprintf_filtered (file, _("\
 751 Printing of thread events is %s.\n"),
 752                     value);
 753 }
 754
 755 static int
 756 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
 757 {
 758   int num;
 759   struct thread_info *tp;
 760
 761   num = value_as_long (parse_and_eval (tidstr));
 762
 763   tp = find_thread_id (num);
 764
 765   if (!tp)
 766     error (_("Thread ID %d not known."), num);
 767
 768   if (!thread_alive (tp))
 769     error (_("Thread ID %d has terminated."), num);
 770
 771   switch_to_thread (tp->ptid);
 772
 773   ui_out_text (uiout, "[Switching to thread ");
 774   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
 775   ui_out_text (uiout, " (");
 776   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
 777   ui_out_text (uiout, ")]");
 778
 779   print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
 780   return GDB_RC_OK;
 781 }
 782
 783 enum gdb_rc
 784 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
 785 {
 786   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
 787                                  error_message, RETURN_MASK_ALL) < 0)
 788     return GDB_RC_FAIL;
 789   return GDB_RC_OK;
 790 }
 791
 792 /* Commands with a prefix of `thread'.  */
 793 struct cmd_list_element *thread_cmd_list = NULL;
 794
 795 void
 796 _initialize_thread (void)
 797 {
 798   static struct cmd_list_element *thread_apply_list = NULL;
 799
 800   add_info ("threads", info_threads_command,
 801             _("IDs of currently known threads."));
 802
 803   add_prefix_cmd ("thread", class_run, thread_command, _("\
 804 Use this command to switch between threads.\n\
 805 The new thread ID must be currently known."),
 806                   &thread_cmd_list, "thread ", 1, &cmdlist);
 807
 808   add_prefix_cmd ("apply", class_run, thread_apply_command,
 809                   _("Apply a command to a list of threads."),
 810                   &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
 811
 812   add_cmd ("all", class_run, thread_apply_all_command,
 813            _("Apply a command to all threads."), &thread_apply_list);
 814
 815   if (!xdb_commands)
 816     add_com_alias ("t", "thread", class_run, 1);
 817
 818   add_setshow_boolean_cmd ("thread-events", no_class,
 819          &print_thread_events, _("\
 820 Set printing of thread events (e.g., thread start and exit)."), _("\
 821 Show printing of thread events (e.g., thread start and exit)."), NULL,
 822          NULL,
 823          show_print_thread_events,
 824          &setprintlist, &showprintlist);
 825 }