gdb/thread-db.c

   1 /* libthread_db assisted debugging support, generic parts.
   2
   3    Copyright 1999, 2000, 2001, 2003 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23
  24 #include "gdb_assert.h"
  25 #include <dlfcn.h>
  26 #include "gdb_proc_service.h"
  27 #include "gdb_thread_db.h"
  28
  29 #include "bfd.h"
  30 #include "gdbthread.h"
  31 #include "inferior.h"
  32 #include "symfile.h"
  33 #include "objfiles.h"
  34 #include "target.h"
  35 #include "regcache.h"
  36 #include "solib-svr4.h"
  37
  38 #ifndef LIBTHREAD_DB_SO
  39 #define LIBTHREAD_DB_SO "libthread_db.so.1"
  40 #endif
  41
  42 /* If we're running on GNU/Linux, we must explicitly attach to any new
  43    threads.  */
  44
  45 /* FIXME: There is certainly some room for improvements:
  46    - Cache LWP ids.
  47    - Bypass libthread_db when fetching or storing registers for
  48    threads bound to a LWP.  */
  49
  50 /* This module's target vector.  */
  51 static struct target_ops thread_db_ops;
  52
  53 /* The target vector that we call for things this module can't handle.  */
  54 static struct target_ops *target_beneath;
  55
  56 /* Pointer to the next function on the objfile event chain.  */
  57 static void (*target_new_objfile_chain) (struct objfile * objfile);
  58
  59 /* Non-zero if we're using this module's target vector.  */
  60 static int using_thread_db;
  61
  62 /* Non-zero if we have to keep this module's target vector active
  63    across re-runs.  */
  64 static int keep_thread_db;
  65
  66 /* Non-zero if we have determined the signals used by the threads
  67    library.  */
  68 static int thread_signals;
  69 static sigset_t thread_stop_set;
  70 static sigset_t thread_print_set;
  71
  72 /* Structure that identifies the child process for the
  73    <proc_service.h> interface.  */
  74 static struct ps_prochandle proc_handle;
  75
  76 /* Connection to the libthread_db library.  */
  77 static td_thragent_t *thread_agent;
  78
  79 /* Pointers to the libthread_db functions.  */
  80
  81 static td_err_e (*td_init_p) (void);
  82
  83 static td_err_e (*td_ta_new_p) (struct ps_prochandle * ps,
  84                                 td_thragent_t **ta);
  85 static td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt,
  86                                        td_thrhandle_t *__th);
  87 static td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta,
  88                                         lwpid_t lwpid, td_thrhandle_t *th);
  89 static td_err_e (*td_ta_thr_iter_p) (const td_thragent_t *ta,
  90                                      td_thr_iter_f *callback, void *cbdata_p,
  91                                      td_thr_state_e state, int ti_pri,
  92                                      sigset_t *ti_sigmask_p,
  93                                      unsigned int ti_user_flags);
  94 static td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta,
  95                                        td_event_e event, td_notify_t *ptr);
  96 static td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta,
  97                                       td_thr_events_t *event);
  98 static td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta,
  99                                          td_event_msg_t *msg);
 100
 101 static td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th);
 102 static td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th,
 103                                       td_thrinfo_t *infop);
 104 static td_err_e (*td_thr_getfpregs_p) (const td_thrhandle_t *th,
 105                                        gdb_prfpregset_t *regset);
 106 static td_err_e (*td_thr_getgregs_p) (const td_thrhandle_t *th,
 107                                       prgregset_t gregs);
 108 static td_err_e (*td_thr_setfpregs_p) (const td_thrhandle_t *th,
 109                                        const gdb_prfpregset_t *fpregs);
 110 static td_err_e (*td_thr_setgregs_p) (const td_thrhandle_t *th,
 111                                       prgregset_t gregs);
 112 static td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th,
 113                                           int event);
 114
 115 static td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,
 116                                           void *map_address,
 117                                           size_t offset, void **address);
 118
 119 /* Location of the thread creation event breakpoint.  The code at this
 120    location in the child process will be called by the pthread library
 121    whenever a new thread is created.  By setting a special breakpoint
 122    at this location, GDB can detect when a new thread is created.  We
 123    obtain this location via the td_ta_event_addr call.  */
 124 static CORE_ADDR td_create_bp_addr;
 125
 126 /* Location of the thread death event breakpoint.  */
 127 static CORE_ADDR td_death_bp_addr;
 128
 129 /* Prototypes for local functions.  */
 130 static void thread_db_find_new_threads (void);
 131 static void attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
 132                            const td_thrinfo_t *ti_p, int verbose);
 133 \f
 134
 135 /* Building process ids.  */
 136
 137 #define GET_PID(ptid)           ptid_get_pid (ptid)
 138 #define GET_LWP(ptid)           ptid_get_lwp (ptid)
 139 #define GET_THREAD(ptid)        ptid_get_tid (ptid)
 140
 141 #define is_lwp(ptid)            (GET_LWP (ptid) != 0)
 142 #define is_thread(ptid)         (GET_THREAD (ptid) != 0)
 143
 144 #define BUILD_LWP(lwp, pid)     ptid_build (pid, lwp, 0)
 145 #define BUILD_THREAD(tid, pid)  ptid_build (pid, 0, tid)
 146 \f
 147
 148 /* Use "struct private_thread_info" to cache thread state.  This is
 149    a substantial optimization.  */
 150
 151 struct private_thread_info
 152 {
 153   /* Cached thread state.  */
 154   unsigned int th_valid:1;
 155   unsigned int ti_valid:1;
 156
 157   td_thrhandle_t th;
 158   td_thrinfo_t ti;
 159 };
 160 \f
 161
 162 static char *
 163 thread_db_err_str (td_err_e err)
 164 {
 165   static char buf[64];
 166
 167   switch (err)
 168     {
 169     case TD_OK:
 170       return "generic 'call succeeded'";
 171     case TD_ERR:
 172       return "generic error";
 173     case TD_NOTHR:
 174       return "no thread to satisfy query";
 175     case TD_NOSV:
 176       return "no sync handle to satisfy query";
 177     case TD_NOLWP:
 178       return "no LWP to satisfy query";
 179     case TD_BADPH:
 180       return "invalid process handle";
 181     case TD_BADTH:
 182       return "invalid thread handle";
 183     case TD_BADSH:
 184       return "invalid synchronization handle";
 185     case TD_BADTA:
 186       return "invalid thread agent";
 187     case TD_BADKEY:
 188       return "invalid key";
 189     case TD_NOMSG:
 190       return "no event message for getmsg";
 191     case TD_NOFPREGS:
 192       return "FPU register set not available";
 193     case TD_NOLIBTHREAD:
 194       return "application not linked with libthread";
 195     case TD_NOEVENT:
 196       return "requested event is not supported";
 197     case TD_NOCAPAB:
 198       return "capability not available";
 199     case TD_DBERR:
 200       return "debugger service failed";
 201     case TD_NOAPLIC:
 202       return "operation not applicable to";
 203     case TD_NOTSD:
 204       return "no thread-specific data for this thread";
 205     case TD_MALLOC:
 206       return "malloc failed";
 207     case TD_PARTIALREG:
 208       return "only part of register set was written/read";
 209     case TD_NOXREGS:
 210       return "X register set not available for this thread";
 211     default:
 212       snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
 213       return buf;
 214     }
 215 }
 216
 217 static char *
 218 thread_db_state_str (td_thr_state_e state)
 219 {
 220   static char buf[64];
 221
 222   switch (state)
 223     {
 224     case TD_THR_STOPPED:
 225       return "stopped by debugger";
 226     case TD_THR_RUN:
 227       return "runnable";
 228     case TD_THR_ACTIVE:
 229       return "active";
 230     case TD_THR_ZOMBIE:
 231       return "zombie";
 232     case TD_THR_SLEEP:
 233       return "sleeping";
 234     case TD_THR_STOPPED_ASLEEP:
 235       return "stopped by debugger AND blocked";
 236     default:
 237       snprintf (buf, sizeof (buf), "unknown thread_db state %d", state);
 238       return buf;
 239     }
 240 }
 241 \f
 242 /* A callback function for td_ta_thr_iter, which we use to map all
 243    threads to LWPs.
 244
 245    THP is a handle to the current thread; if INFOP is not NULL, the
 246    struct thread_info associated with this thread is returned in
 247    *INFOP.  */
 248
 249 static int
 250 thread_get_info_callback (const td_thrhandle_t *thp, void *infop)
 251 {
 252   td_thrinfo_t ti;
 253   td_err_e err;
 254   struct thread_info *thread_info;
 255   ptid_t thread_ptid;
 256
 257   err = td_thr_get_info_p (thp, &ti);
 258   if (err != TD_OK)
 259     error ("thread_get_info_callback: cannot get thread info: %s",
 260            thread_db_err_str (err));
 261
 262   /* Fill the cache.  */
 263   thread_ptid = BUILD_THREAD (ti.ti_tid, GET_PID (inferior_ptid));
 264   thread_info = find_thread_pid (thread_ptid);
 265
 266   if (thread_info == NULL)
 267     {
 268       /* New thread.  Attach to it now (why wait?).  */
 269       attach_thread (thread_ptid, thp, &ti, 1);
 270       thread_info = find_thread_pid (thread_ptid);
 271       gdb_assert (thread_info != NULL);
 272     }
 273
 274   memcpy (&thread_info->private->th, thp, sizeof (*thp));
 275   thread_info->private->th_valid = 1;
 276   memcpy (&thread_info->private->ti, &ti, sizeof (ti));
 277   thread_info->private->ti_valid = 1;
 278
 279   if (infop != NULL)
 280     *(struct thread_info **) infop = thread_info;
 281
 282   return 0;
 283 }
 284
 285 /* Accessor functions for the thread_db information, with caching.  */
 286
 287 static void
 288 thread_db_map_id2thr (struct thread_info *thread_info, int fatal)
 289 {
 290   td_err_e err;
 291
 292   if (thread_info->private->th_valid)
 293     return;
 294
 295   err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (thread_info->ptid),
 296                             &thread_info->private->th);
 297   if (err != TD_OK)
 298     {
 299       if (fatal)
 300         error ("Cannot find thread %ld: %s",
 301                (long) GET_THREAD (thread_info->ptid),
 302                thread_db_err_str (err));
 303     }
 304   else
 305     thread_info->private->th_valid = 1;
 306 }
 307
 308 static td_thrinfo_t *
 309 thread_db_get_info (struct thread_info *thread_info)
 310 {
 311   td_err_e err;
 312
 313   if (thread_info->private->ti_valid)
 314     return &thread_info->private->ti;
 315
 316   if (!thread_info->private->th_valid)
 317     thread_db_map_id2thr (thread_info, 1);
 318
 319   err =
 320     td_thr_get_info_p (&thread_info->private->th, &thread_info->private->ti);
 321   if (err != TD_OK)
 322     error ("thread_db_get_info: cannot get thread info: %s",
 323            thread_db_err_str (err));
 324
 325   thread_info->private->ti_valid = 1;
 326   return &thread_info->private->ti;
 327 }
 328 \f
 329 /* Convert between user-level thread ids and LWP ids.  */
 330
 331 static ptid_t
 332 thread_from_lwp (ptid_t ptid)
 333 {
 334   td_thrhandle_t th;
 335   td_err_e err;
 336   struct thread_info *thread_info;
 337   ptid_t thread_ptid;
 338
 339   if (GET_LWP (ptid) == 0)
 340     ptid = BUILD_LWP (GET_PID (ptid), GET_PID (ptid));
 341
 342   gdb_assert (is_lwp (ptid));
 343
 344   err = td_ta_map_lwp2thr_p (thread_agent, GET_LWP (ptid), &th);
 345   if (err != TD_OK)
 346     error ("Cannot find user-level thread for LWP %ld: %s",
 347            GET_LWP (ptid), thread_db_err_str (err));
 348
 349   thread_info = NULL;
 350   thread_get_info_callback (&th, &thread_info);
 351   gdb_assert (thread_info && thread_info->private->ti_valid);
 352
 353   return BUILD_THREAD (thread_info->private->ti.ti_tid, GET_PID (ptid));
 354 }
 355
 356 static ptid_t
 357 lwp_from_thread (ptid_t ptid)
 358 {
 359   struct thread_info *thread_info;
 360   ptid_t thread_ptid;
 361
 362   if (!is_thread (ptid))
 363     return ptid;
 364
 365   thread_info = find_thread_pid (ptid);
 366   thread_db_get_info (thread_info);
 367
 368   return BUILD_LWP (thread_info->private->ti.ti_lid, GET_PID (ptid));
 369 }
 370 \f
 371
 372 void
 373 thread_db_init (struct target_ops *target)
 374 {
 375   target_beneath = target;
 376 }
 377
 378 static void *
 379 verbose_dlsym (void *handle, const char *name)
 380 {
 381   void *sym = dlsym (handle, name);
 382   if (sym == NULL)
 383     warning ("Symbol \"%s\" not found in libthread_db: %s", name, dlerror ());
 384   return sym;
 385 }
 386
 387 static int
 388 thread_db_load (void)
 389 {
 390   void *handle;
 391   td_err_e err;
 392
 393   handle = dlopen (LIBTHREAD_DB_SO, RTLD_NOW);
 394   if (handle == NULL)
 395     {
 396       fprintf_filtered (gdb_stderr, "\n\ndlopen failed on '%s' - %s\n",
 397                         LIBTHREAD_DB_SO, dlerror ());
 398       fprintf_filtered (gdb_stderr,
 399                         "GDB will not be able to debug pthreads.\n\n");
 400       return 0;
 401     }
 402
 403   /* Initialize pointers to the dynamic library functions we will use.
 404      Essential functions first.  */
 405
 406   td_init_p = verbose_dlsym (handle, "td_init");
 407   if (td_init_p == NULL)
 408     return 0;
 409
 410   td_ta_new_p = verbose_dlsym (handle, "td_ta_new");
 411   if (td_ta_new_p == NULL)
 412     return 0;
 413
 414   td_ta_map_id2thr_p = verbose_dlsym (handle, "td_ta_map_id2thr");
 415   if (td_ta_map_id2thr_p == NULL)
 416     return 0;
 417
 418   td_ta_map_lwp2thr_p = verbose_dlsym (handle, "td_ta_map_lwp2thr");
 419   if (td_ta_map_lwp2thr_p == NULL)
 420     return 0;
 421
 422   td_ta_thr_iter_p = verbose_dlsym (handle, "td_ta_thr_iter");
 423   if (td_ta_thr_iter_p == NULL)
 424     return 0;
 425
 426   td_thr_validate_p = verbose_dlsym (handle, "td_thr_validate");
 427   if (td_thr_validate_p == NULL)
 428     return 0;
 429
 430   td_thr_get_info_p = verbose_dlsym (handle, "td_thr_get_info");
 431   if (td_thr_get_info_p == NULL)
 432     return 0;
 433
 434   td_thr_getfpregs_p = verbose_dlsym (handle, "td_thr_getfpregs");
 435   if (td_thr_getfpregs_p == NULL)
 436     return 0;
 437
 438   td_thr_getgregs_p = verbose_dlsym (handle, "td_thr_getgregs");
 439   if (td_thr_getgregs_p == NULL)
 440     return 0;
 441
 442   td_thr_setfpregs_p = verbose_dlsym (handle, "td_thr_setfpregs");
 443   if (td_thr_setfpregs_p == NULL)
 444     return 0;
 445
 446   td_thr_setgregs_p = verbose_dlsym (handle, "td_thr_setgregs");
 447   if (td_thr_setgregs_p == NULL)
 448     return 0;
 449
 450   /* Initialize the library.  */
 451   err = td_init_p ();
 452   if (err != TD_OK)
 453     {
 454       warning ("Cannot initialize libthread_db: %s", thread_db_err_str (err));
 455       return 0;
 456     }
 457
 458   /* These are not essential.  */
 459   td_ta_event_addr_p = dlsym (handle, "td_ta_event_addr");
 460   td_ta_set_event_p = dlsym (handle, "td_ta_set_event");
 461   td_ta_event_getmsg_p = dlsym (handle, "td_ta_event_getmsg");
 462   td_thr_event_enable_p = dlsym (handle, "td_thr_event_enable");
 463   td_thr_tls_get_addr_p = dlsym (handle, "td_thr_tls_get_addr");
 464
 465   return 1;
 466 }
 467
 468 static td_err_e
 469 enable_thread_event (td_thragent_t *thread_agent, int event, CORE_ADDR *bp)
 470 {
 471   td_notify_t notify;
 472   td_err_e err;
 473
 474   /* Get the breakpoint address for thread EVENT.  */
 475   err = td_ta_event_addr_p (thread_agent, event, &notify);
 476   if (err != TD_OK)
 477     return err;
 478
 479   /* Set up the breakpoint.  */
 480   (*bp) = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 481                                               (CORE_ADDR) notify.u.bptaddr,
 482                                               &current_target);
 483   create_thread_event_breakpoint ((*bp));
 484
 485   return TD_OK;
 486 }
 487
 488 static void
 489 enable_thread_event_reporting (void)
 490 {
 491   td_thr_events_t events;
 492   td_notify_t notify;
 493   td_err_e err;
 494
 495   /* We cannot use the thread event reporting facility if these
 496      functions aren't available.  */
 497   if (td_ta_event_addr_p == NULL || td_ta_set_event_p == NULL
 498       || td_ta_event_getmsg_p == NULL || td_thr_event_enable_p == NULL)
 499     return;
 500
 501   /* Set the process wide mask saying which events we're interested in.  */
 502   td_event_emptyset (&events);
 503   td_event_addset (&events, TD_CREATE);
 504 #if 0
 505   /* FIXME: kettenis/2000-04-23: The event reporting facility is
 506      broken for TD_DEATH events in glibc 2.1.3, so don't enable it for
 507      now.  */
 508   td_event_addset (&events, TD_DEATH);
 509 #endif
 510
 511   err = td_ta_set_event_p (thread_agent, &events);
 512   if (err != TD_OK)
 513     {
 514       warning ("Unable to set global thread event mask: %s",
 515                thread_db_err_str (err));
 516       return;
 517     }
 518
 519   /* Delete previous thread event breakpoints, if any.  */
 520   remove_thread_event_breakpoints ();
 521   td_create_bp_addr = 0;
 522   td_death_bp_addr = 0;
 523
 524   /* Set up the thread creation event.  */
 525   err = enable_thread_event (thread_agent, TD_CREATE, &td_create_bp_addr);
 526   if (err != TD_OK)
 527     {
 528       warning ("Unable to get location for thread creation breakpoint: %s",
 529                thread_db_err_str (err));
 530       return;
 531     }
 532
 533   /* Set up the thread death event.  */
 534   err = enable_thread_event (thread_agent, TD_DEATH, &td_death_bp_addr);
 535   if (err != TD_OK)
 536     {
 537       warning ("Unable to get location for thread death breakpoint: %s",
 538                thread_db_err_str (err));
 539       return;
 540     }
 541 }
 542
 543 static void
 544 disable_thread_event_reporting (void)
 545 {
 546   td_thr_events_t events;
 547
 548   /* Set the process wide mask saying we aren't interested in any
 549      events anymore.  */
 550   td_event_emptyset (&events);
 551   td_ta_set_event_p (thread_agent, &events);
 552
 553   /* Delete thread event breakpoints, if any.  */
 554   remove_thread_event_breakpoints ();
 555   td_create_bp_addr = 0;
 556   td_death_bp_addr = 0;
 557 }
 558
 559 static void
 560 check_thread_signals (void)
 561 {
 562 #ifdef GET_THREAD_SIGNALS
 563   if (!thread_signals)
 564     {
 565       sigset_t mask;
 566       int i;
 567
 568       GET_THREAD_SIGNALS (&mask);
 569       sigemptyset (&thread_stop_set);
 570       sigemptyset (&thread_print_set);
 571
 572       for (i = 1; i < NSIG; i++)
 573         {
 574           if (sigismember (&mask, i))
 575             {
 576               if (signal_stop_update (target_signal_from_host (i), 0))
 577                 sigaddset (&thread_stop_set, i);
 578               if (signal_print_update (target_signal_from_host (i), 0))
 579                 sigaddset (&thread_print_set, i);
 580               thread_signals = 1;
 581             }
 582         }
 583     }
 584 #endif
 585 }
 586
 587 static void
 588 thread_db_new_objfile (struct objfile *objfile)
 589 {
 590   td_err_e err;
 591
 592   /* First time through, report that libthread_db was successfuly
 593      loaded.  Can't print this in in thread_db_load as, at that stage,
 594      the interpreter and it's console haven't started.  The real
 595      problem here is that libthread_db is loaded too early - it should
 596      only be loaded when there is a program to debug.  */
 597   {
 598     static int dejavu;
 599     if (!dejavu)
 600       {
 601         Dl_info info;
 602         const char *library = NULL;
 603         /* Try dladdr.  */
 604         if (dladdr ((*td_ta_new_p), &info) != 0)
 605           library = info.dli_fname;
 606         /* Try dlinfo?  */
 607         if (library == NULL)
 608           /* Paranoid - don't let a NULL path slip through.  */
 609           library = LIBTHREAD_DB_SO;
 610         printf_unfiltered ("Using host libthread_db library \"%s\".\n",
 611                            library);
 612         dejavu = 1;
 613       }
 614   }
 615
 616   /* Don't attempt to use thread_db on targets which can not run
 617      (core files).  */
 618   if (objfile == NULL || !target_has_execution)
 619     {
 620       /* All symbols have been discarded.  If the thread_db target is
 621          active, deactivate it now.  */
 622       if (using_thread_db)
 623         {
 624           gdb_assert (proc_handle.pid == 0);
 625           unpush_target (&thread_db_ops);
 626           using_thread_db = 0;
 627         }
 628
 629       keep_thread_db = 0;
 630
 631       goto quit;
 632     }
 633
 634   if (using_thread_db)
 635     /* Nothing to do.  The thread library was already detected and the
 636        target vector was already activated.  */
 637     goto quit;
 638
 639   /* Initialize the structure that identifies the child process.  Note
 640      that at this point there is no guarantee that we actually have a
 641      child process.  */
 642   proc_handle.pid = GET_PID (inferior_ptid);
 643
 644   /* Now attempt to open a connection to the thread library.  */
 645   err = td_ta_new_p (&proc_handle, &thread_agent);
 646   switch (err)
 647     {
 648     case TD_NOLIBTHREAD:
 649       /* No thread library was detected.  */
 650       break;
 651
 652     case TD_OK:
 653       printf_unfiltered ("[Thread debugging using libthread_db enabled]\n");
 654
 655       /* The thread library was detected.  Activate the thread_db target.  */
 656       push_target (&thread_db_ops);
 657       using_thread_db = 1;
 658
 659       /* If the thread library was detected in the main symbol file
 660          itself, we assume that the program was statically linked
 661          against the thread library and well have to keep this
 662          module's target vector activated until forever...  Well, at
 663          least until all symbols have been discarded anyway (see
 664          above).  */
 665       if (objfile == symfile_objfile)
 666         {
 667           gdb_assert (proc_handle.pid == 0);
 668           keep_thread_db = 1;
 669         }
 670
 671       /* We can only poke around if there actually is a child process.
 672          If there is no child process alive, postpone the steps below
 673          until one has been created.  */
 674       if (proc_handle.pid != 0)
 675         {
 676           enable_thread_event_reporting ();
 677           thread_db_find_new_threads ();
 678         }
 679       break;
 680
 681     default:
 682       warning ("Cannot initialize thread debugging library: %s",
 683                thread_db_err_str (err));
 684       break;
 685     }
 686
 687 quit:
 688   if (target_new_objfile_chain)
 689     target_new_objfile_chain (objfile);
 690 }
 691
 692 static void
 693 attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
 694                const td_thrinfo_t *ti_p, int verbose)
 695 {
 696   struct thread_info *tp;
 697   td_err_e err;
 698
 699   check_thread_signals ();
 700
 701   /* Add the thread to GDB's thread list.  */
 702   tp = add_thread (ptid);
 703   tp->private = xmalloc (sizeof (struct private_thread_info));
 704   memset (tp->private, 0, sizeof (struct private_thread_info));
 705
 706   if (verbose)
 707     printf_unfiltered ("[New %s]\n", target_pid_to_str (ptid));
 708
 709   if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE)
 710     return;                     /* A zombie thread -- do not attach.  */
 711
 712   /* Under GNU/Linux, we have to attach to each and every thread.  */
 713 #ifdef ATTACH_LWP
 714   ATTACH_LWP (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)), 0);
 715 #endif
 716
 717   /* Enable thread event reporting for this thread.  */
 718   err = td_thr_event_enable_p (th_p, 1);
 719   if (err != TD_OK)
 720     error ("Cannot enable thread event reporting for %s: %s",
 721            target_pid_to_str (ptid), thread_db_err_str (err));
 722 }
 723
 724 static void
 725 thread_db_attach (char *args, int from_tty)
 726 {
 727   target_beneath->to_attach (args, from_tty);
 728
 729   /* Destroy thread info; it's no longer valid.  */
 730   init_thread_list ();
 731
 732   /* The child process is now the actual multi-threaded
 733      program.  Snatch its process ID...  */
 734   proc_handle.pid = GET_PID (inferior_ptid);
 735
 736   /* ...and perform the remaining initialization steps.  */
 737   enable_thread_event_reporting ();
 738   thread_db_find_new_threads ();
 739 }
 740
 741 static void
 742 detach_thread (ptid_t ptid, int verbose)
 743 {
 744   if (verbose)
 745     printf_unfiltered ("[%s exited]\n", target_pid_to_str (ptid));
 746 }
 747
 748 static void
 749 thread_db_detach (char *args, int from_tty)
 750 {
 751   disable_thread_event_reporting ();
 752
 753   /* There's no need to save & restore inferior_ptid here, since the
 754      inferior is supposed to be survive this function call.  */
 755   inferior_ptid = lwp_from_thread (inferior_ptid);
 756
 757   /* Forget about the child's process ID.  We shouldn't need it
 758      anymore.  */
 759   proc_handle.pid = 0;
 760
 761   target_beneath->to_detach (args, from_tty);
 762 }
 763
 764 static int
 765 clear_lwpid_callback (struct thread_info *thread, void *dummy)
 766 {
 767   /* If we know that our thread implementation is 1-to-1, we could save
 768      a certain amount of information; it's not clear how much, so we
 769      are always conservative.  */
 770
 771   thread->private->th_valid = 0;
 772   thread->private->ti_valid = 0;
 773
 774   return 0;
 775 }
 776
 777 static void
 778 thread_db_resume (ptid_t ptid, int step, enum target_signal signo)
 779 {
 780   struct cleanup *old_chain = save_inferior_ptid ();
 781
 782   if (GET_PID (ptid) == -1)
 783     inferior_ptid = lwp_from_thread (inferior_ptid);
 784   else if (is_thread (ptid))
 785     ptid = lwp_from_thread (ptid);
 786
 787   /* Clear cached data which may not be valid after the resume.  */
 788   iterate_over_threads (clear_lwpid_callback, NULL);
 789
 790   target_beneath->to_resume (ptid, step, signo);
 791
 792   do_cleanups (old_chain);
 793 }
 794
 795 /* Check if PID is currently stopped at the location of a thread event
 796    breakpoint location.  If it is, read the event message and act upon
 797    the event.  */
 798
 799 static void
 800 check_event (ptid_t ptid)
 801 {
 802   td_event_msg_t msg;
 803   td_thrinfo_t ti;
 804   td_err_e err;
 805   CORE_ADDR stop_pc;
 806   int loop = 0;
 807
 808   /* Bail out early if we're not at a thread event breakpoint.  */
 809   stop_pc = read_pc_pid (ptid) - DECR_PC_AFTER_BREAK;
 810   if (stop_pc != td_create_bp_addr && stop_pc != td_death_bp_addr)
 811     return;
 812
 813   /* If we are at a create breakpoint, we do not know what new lwp
 814      was created and cannot specifically locate the event message for it.
 815      We have to call td_ta_event_getmsg() to get
 816      the latest message.  Since we have no way of correlating whether
 817      the event message we get back corresponds to our breakpoint, we must
 818      loop and read all event messages, processing them appropriately.
 819      This guarantees we will process the correct message before continuing
 820      from the breakpoint.
 821
 822      Currently, death events are not enabled.  If they are enabled,
 823      the death event can use the td_thr_event_getmsg() interface to
 824      get the message specifically for that lwp and avoid looping
 825      below.  */
 826
 827   loop = 1;
 828
 829   do
 830     {
 831       err = td_ta_event_getmsg_p (thread_agent, &msg);
 832       if (err != TD_OK)
 833         {
 834           if (err == TD_NOMSG)
 835             return;
 836
 837           error ("Cannot get thread event message: %s",
 838                  thread_db_err_str (err));
 839         }
 840
 841       err = td_thr_get_info_p (msg.th_p, &ti);
 842       if (err != TD_OK)
 843         error ("Cannot get thread info: %s", thread_db_err_str (err));
 844
 845       ptid = BUILD_THREAD (ti.ti_tid, GET_PID (ptid));
 846
 847       switch (msg.event)
 848         {
 849         case TD_CREATE:
 850
 851           /* We may already know about this thread, for instance when the
 852              user has issued the `info threads' command before the SIGTRAP
 853              for hitting the thread creation breakpoint was reported.  */
 854           if (!in_thread_list (ptid))
 855             attach_thread (ptid, msg.th_p, &ti, 1);
 856
 857           break;
 858
 859         case TD_DEATH:
 860
 861           if (!in_thread_list (ptid))
 862             error ("Spurious thread death event.");
 863
 864           detach_thread (ptid, 1);
 865
 866           break;
 867
 868         default:
 869           error ("Spurious thread event.");
 870         }
 871     }
 872   while (loop);
 873 }
 874
 875 static ptid_t
 876 thread_db_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
 877 {
 878   extern ptid_t trap_ptid;
 879
 880   if (GET_PID (ptid) != -1 && is_thread (ptid))
 881     ptid = lwp_from_thread (ptid);
 882
 883   ptid = target_beneath->to_wait (ptid, ourstatus);
 884
 885   if (proc_handle.pid == 0)
 886     /* The current child process isn't the actual multi-threaded
 887        program yet, so don't try to do any special thread-specific
 888        post-processing and bail out early.  */
 889     return ptid;
 890
 891   if (ourstatus->kind == TARGET_WAITKIND_EXITED)
 892     return pid_to_ptid (-1);
 893
 894   if (ourstatus->kind == TARGET_WAITKIND_STOPPED
 895       && ourstatus->value.sig == TARGET_SIGNAL_TRAP)
 896     /* Check for a thread event.  */
 897     check_event (ptid);
 898
 899   if (!ptid_equal (trap_ptid, null_ptid))
 900     trap_ptid = thread_from_lwp (trap_ptid);
 901
 902   return thread_from_lwp (ptid);
 903 }
 904
 905 static int
 906 thread_db_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
 907                        struct mem_attrib *attrib, struct target_ops *target)
 908 {
 909   struct cleanup *old_chain = save_inferior_ptid ();
 910   int xfer;
 911
 912   if (is_thread (inferior_ptid))
 913     {
 914       /* FIXME: This seems to be necessary to make sure breakpoints
 915          are removed.  */
 916       if (!target_thread_alive (inferior_ptid))
 917         inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid));
 918       else
 919         inferior_ptid = lwp_from_thread (inferior_ptid);
 920     }
 921
 922   xfer =
 923     target_beneath->to_xfer_memory (memaddr, myaddr, len, write, attrib,
 924                                     target);
 925
 926   do_cleanups (old_chain);
 927   return xfer;
 928 }
 929
 930 static void
 931 thread_db_fetch_registers (int regno)
 932 {
 933   struct thread_info *thread_info;
 934   prgregset_t gregset;
 935   gdb_prfpregset_t fpregset;
 936   td_err_e err;
 937
 938   if (!is_thread (inferior_ptid))
 939     {
 940       /* Pass the request to the target beneath us.  */
 941       target_beneath->to_fetch_registers (regno);
 942       return;
 943     }
 944
 945   thread_info = find_thread_pid (inferior_ptid);
 946   thread_db_map_id2thr (thread_info, 1);
 947
 948   err = td_thr_getgregs_p (&thread_info->private->th, gregset);
 949   if (err != TD_OK)
 950     error ("Cannot fetch general-purpose registers for thread %ld: %s",
 951            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
 952
 953   err = td_thr_getfpregs_p (&thread_info->private->th, &fpregset);
 954   if (err != TD_OK)
 955     error ("Cannot get floating-point registers for thread %ld: %s",
 956            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
 957
 958   /* Note that we must call supply_gregset after calling the thread_db
 959      routines because the thread_db routines call ps_lgetgregs and
 960      friends which clobber GDB's register cache.  */
 961   supply_gregset ((gdb_gregset_t *) gregset);
 962   supply_fpregset (&fpregset);
 963 }
 964
 965 static void
 966 thread_db_store_registers (int regno)
 967 {
 968   prgregset_t gregset;
 969   gdb_prfpregset_t fpregset;
 970   td_err_e err;
 971   struct thread_info *thread_info;
 972
 973   if (!is_thread (inferior_ptid))
 974     {
 975       /* Pass the request to the target beneath us.  */
 976       target_beneath->to_store_registers (regno);
 977       return;
 978     }
 979
 980   thread_info = find_thread_pid (inferior_ptid);
 981   thread_db_map_id2thr (thread_info, 1);
 982
 983   if (regno != -1)
 984     {
 985       char raw[MAX_REGISTER_SIZE];
 986
 987       deprecated_read_register_gen (regno, raw);
 988       thread_db_fetch_registers (-1);
 989       supply_register (regno, raw);
 990     }
 991
 992   fill_gregset ((gdb_gregset_t *) gregset, -1);
 993   fill_fpregset (&fpregset, -1);
 994
 995   err = td_thr_setgregs_p (&thread_info->private->th, gregset);
 996   if (err != TD_OK)
 997     error ("Cannot store general-purpose registers for thread %ld: %s",
 998            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
 999   err = td_thr_setfpregs_p (&thread_info->private->th, &fpregset);
1000   if (err != TD_OK)
1001     error ("Cannot store floating-point registers  for thread %ld: %s",
1002            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
1003 }
1004
1005 static void
1006 thread_db_kill (void)
1007 {
1008   /* There's no need to save & restore inferior_ptid here, since the
1009      inferior isn't supposed to survive this function call.  */
1010   inferior_ptid = lwp_from_thread (inferior_ptid);
1011   target_beneath->to_kill ();
1012 }
1013
1014 static void
1015 thread_db_create_inferior (char *exec_file, char *allargs, char **env)
1016 {
1017   if (!keep_thread_db)
1018     {
1019       unpush_target (&thread_db_ops);
1020       using_thread_db = 0;
1021     }
1022
1023   target_beneath->to_create_inferior (exec_file, allargs, env);
1024 }
1025
1026 static void
1027 thread_db_post_startup_inferior (ptid_t ptid)
1028 {
1029   if (proc_handle.pid == 0)
1030     {
1031       /* The child process is now the actual multi-threaded
1032          program.  Snatch its process ID...  */
1033       proc_handle.pid = GET_PID (ptid);
1034
1035       /* ...and perform the remaining initialization steps.  */
1036       enable_thread_event_reporting ();
1037       thread_db_find_new_threads ();
1038     }
1039 }
1040
1041 static void
1042 thread_db_mourn_inferior (void)
1043 {
1044   remove_thread_event_breakpoints ();
1045
1046   /* Forget about the child's process ID.  We shouldn't need it
1047      anymore.  */
1048   proc_handle.pid = 0;
1049
1050   target_beneath->to_mourn_inferior ();
1051
1052   /* Detach thread_db target ops if not dealing with a statically
1053      linked threaded program.  This allows a corefile to be debugged
1054      after finishing debugging of a threaded program.  At present,
1055      debugging a statically-linked threaded program is broken, but
1056      the check is added below in the event that it is fixed in the
1057      future.  */
1058   if (!keep_thread_db)
1059     {
1060       unpush_target (&thread_db_ops);
1061       using_thread_db = 0;
1062     }
1063 }
1064
1065 static int
1066 thread_db_thread_alive (ptid_t ptid)
1067 {
1068   td_thrhandle_t th;
1069   td_err_e err;
1070
1071   if (is_thread (ptid))
1072     {
1073       struct thread_info *thread_info;
1074       thread_info = find_thread_pid (ptid);
1075
1076       thread_db_map_id2thr (thread_info, 0);
1077       if (!thread_info->private->th_valid)
1078         return 0;
1079
1080       err = td_thr_validate_p (&thread_info->private->th);
1081       if (err != TD_OK)
1082         return 0;
1083
1084       if (!thread_info->private->ti_valid)
1085         {
1086           err =
1087             td_thr_get_info_p (&thread_info->private->th,
1088                                &thread_info->private->ti);
1089           if (err != TD_OK)
1090             return 0;
1091           thread_info->private->ti_valid = 1;
1092         }
1093
1094       if (thread_info->private->ti.ti_state == TD_THR_UNKNOWN
1095           || thread_info->private->ti.ti_state == TD_THR_ZOMBIE)
1096         return 0;               /* A zombie thread.  */
1097
1098       return 1;
1099     }
1100
1101   if (target_beneath->to_thread_alive)
1102     return target_beneath->to_thread_alive (ptid);
1103
1104   return 0;
1105 }
1106
1107 static int
1108 find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
1109 {
1110   td_thrinfo_t ti;
1111   td_err_e err;
1112   ptid_t ptid;
1113
1114   err = td_thr_get_info_p (th_p, &ti);
1115   if (err != TD_OK)
1116     error ("find_new_threads_callback: cannot get thread info: %s",
1117            thread_db_err_str (err));
1118
1119   if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
1120     return 0;                   /* A zombie -- ignore.  */
1121
1122   ptid = BUILD_THREAD (ti.ti_tid, GET_PID (inferior_ptid));
1123
1124   if (!in_thread_list (ptid))
1125     attach_thread (ptid, th_p, &ti, 1);
1126
1127   return 0;
1128 }
1129
1130 static void
1131 thread_db_find_new_threads (void)
1132 {
1133   td_err_e err;
1134
1135   /* Iterate over all user-space threads to discover new threads.  */
1136   err = td_ta_thr_iter_p (thread_agent, find_new_threads_callback, NULL,
1137                           TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
1138                           TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
1139   if (err != TD_OK)
1140     error ("Cannot find new threads: %s", thread_db_err_str (err));
1141 }
1142
1143 static char *
1144 thread_db_pid_to_str (ptid_t ptid)
1145 {
1146   if (is_thread (ptid))
1147     {
1148       static char buf[64];
1149       td_thrinfo_t *ti_p;
1150       td_err_e err;
1151       struct thread_info *thread_info;
1152
1153       thread_info = find_thread_pid (ptid);
1154       thread_db_map_id2thr (thread_info, 0);
1155       if (!thread_info->private->th_valid)
1156         {
1157           snprintf (buf, sizeof (buf), "Thread %ld (Missing)",
1158                     GET_THREAD (ptid));
1159           return buf;
1160         }
1161
1162       ti_p = thread_db_get_info (thread_info);
1163
1164       if (ti_p->ti_state == TD_THR_ACTIVE && ti_p->ti_lid != 0)
1165         {
1166           snprintf (buf, sizeof (buf), "Thread %ld (LWP %d)",
1167                     (long) ti_p->ti_tid, ti_p->ti_lid);
1168         }
1169       else
1170         {
1171           snprintf (buf, sizeof (buf), "Thread %ld (%s)",
1172                     (long) ti_p->ti_tid,
1173                     thread_db_state_str (ti_p->ti_state));
1174         }
1175
1176       return buf;
1177     }
1178
1179   if (target_beneath->to_pid_to_str (ptid))
1180     return target_beneath->to_pid_to_str (ptid);
1181
1182   return normal_pid_to_str (ptid);
1183 }
1184
1185 /* Get the address of the thread local variable in OBJFILE which is
1186    stored at OFFSET within the thread local storage for thread PTID.  */
1187
1188 static CORE_ADDR
1189 thread_db_get_thread_local_address (ptid_t ptid, struct objfile *objfile,
1190                                     CORE_ADDR offset)
1191 {
1192   if (is_thread (ptid))
1193     {
1194       int objfile_is_library = (objfile->flags & OBJF_SHARED);
1195       td_err_e err;
1196       void *address;
1197       CORE_ADDR lm;
1198       struct thread_info *thread_info;
1199
1200       /* glibc doesn't provide the needed interface.  */
1201       if (!td_thr_tls_get_addr_p)
1202         error ("Cannot find thread-local variables in this thread library.");
1203
1204       /* Get the address of the link map for this objfile.  */
1205       lm = svr4_fetch_objfile_link_map (objfile);
1206
1207       /* Whoops, we couldn't find one. Bail out.  */
1208       if (!lm)
1209         {
1210           if (objfile_is_library)
1211             error ("Cannot find shared library `%s' link_map in dynamic"
1212                    " linker's module list", objfile->name);
1213           else
1214             error ("Cannot find executable file `%s' link_map in dynamic"
1215                    " linker's module list", objfile->name);
1216         }
1217
1218       /* Get info about the thread.  */
1219       thread_info = find_thread_pid (ptid);
1220       thread_db_map_id2thr (thread_info, 1);
1221
1222       /* Finally, get the address of the variable.  */
1223       err = td_thr_tls_get_addr_p (&thread_info->private->th, (void *) lm,
1224                                    offset, &address);
1225
1226 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1227       /* The memory hasn't been allocated, yet.  */
1228       if (err == TD_NOTALLOC)
1229         {
1230           /* Now, if libthread_db provided the initialization image's
1231              address, we *could* try to build a non-lvalue value from
1232              the initialization image.  */
1233           if (objfile_is_library)
1234             error ("The inferior has not yet allocated storage for"
1235                    " thread-local variables in\n"
1236                    "the shared library `%s'\n"
1237                    "for the thread %ld",
1238                    objfile->name, (long) GET_THREAD (ptid));
1239           else
1240             error ("The inferior has not yet allocated storage for"
1241                    " thread-local variables in\n"
1242                    "the executable `%s'\n"
1243                    "for the thread %ld",
1244                    objfile->name, (long) GET_THREAD (ptid));
1245         }
1246 #endif
1247
1248       /* Something else went wrong.  */
1249       if (err != TD_OK)
1250         {
1251           if (objfile_is_library)
1252             error ("Cannot find thread-local storage for thread %ld, "
1253                    "shared library %s:\n%s",
1254                    (long) GET_THREAD (ptid),
1255                    objfile->name, thread_db_err_str (err));
1256           else
1257             error ("Cannot find thread-local storage for thread %ld, "
1258                    "executable file %s:\n%s",
1259                    (long) GET_THREAD (ptid),
1260                    objfile->name, thread_db_err_str (err));
1261         }
1262
1263       /* Cast assuming host == target.  Joy.  */
1264       return (CORE_ADDR) address;
1265     }
1266
1267   if (target_beneath->to_get_thread_local_address)
1268     return target_beneath->to_get_thread_local_address (ptid, objfile,
1269                                                         offset);
1270
1271   error ("Cannot find thread-local values on this target.");
1272 }
1273
1274 static void
1275 init_thread_db_ops (void)
1276 {
1277   thread_db_ops.to_shortname = "multi-thread";
1278   thread_db_ops.to_longname = "multi-threaded child process.";
1279   thread_db_ops.to_doc = "Threads and pthreads support.";
1280   thread_db_ops.to_attach = thread_db_attach;
1281   thread_db_ops.to_detach = thread_db_detach;
1282   thread_db_ops.to_resume = thread_db_resume;
1283   thread_db_ops.to_wait = thread_db_wait;
1284   thread_db_ops.to_fetch_registers = thread_db_fetch_registers;
1285   thread_db_ops.to_store_registers = thread_db_store_registers;
1286   thread_db_ops.to_xfer_memory = thread_db_xfer_memory;
1287   thread_db_ops.to_kill = thread_db_kill;
1288   thread_db_ops.to_create_inferior = thread_db_create_inferior;
1289   thread_db_ops.to_post_startup_inferior = thread_db_post_startup_inferior;
1290   thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior;
1291   thread_db_ops.to_thread_alive = thread_db_thread_alive;
1292   thread_db_ops.to_find_new_threads = thread_db_find_new_threads;
1293   thread_db_ops.to_pid_to_str = thread_db_pid_to_str;
1294   thread_db_ops.to_stratum = thread_stratum;
1295   thread_db_ops.to_has_thread_control = tc_schedlock;
1296   thread_db_ops.to_get_thread_local_address
1297     = thread_db_get_thread_local_address;
1298   thread_db_ops.to_magic = OPS_MAGIC;
1299 }
1300
1301 void
1302 _initialize_thread_db (void)
1303 {
1304   /* Only initialize the module if we can load libthread_db.  */
1305   if (thread_db_load ())
1306     {
1307       init_thread_db_ops ();
1308       add_target (&thread_db_ops);
1309
1310       /* Add ourselves to objfile event chain.  */
1311       target_new_objfile_chain = target_new_objfile_hook;
1312       target_new_objfile_hook = thread_db_new_objfile;
1313     }
1314 }