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 int
 469 enable_thread_event (td_thragent_t *thread_agent, int event, CORE_ADDR *bp)
 470 {
 471   td_notify_t notify;
 472   int 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 0;
 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 1;
 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   if (!enable_thread_event (thread_agent, TD_CREATE, &td_create_bp_addr))
 526     {
 527       warning ("Unable to get location for thread creation breakpoint: %s",
 528                thread_db_err_str (err));
 529       return;
 530     }
 531
 532   /* Set up the thread death event.  */
 533   if (!enable_thread_event (thread_agent, TD_DEATH, &td_death_bp_addr))
 534     {
 535       warning ("Unable to get location for thread death breakpoint: %s",
 536                thread_db_err_str (err));
 537       return;
 538     }
 539 }
 540
 541 static void
 542 disable_thread_event_reporting (void)
 543 {
 544   td_thr_events_t events;
 545
 546   /* Set the process wide mask saying we aren't interested in any
 547      events anymore.  */
 548   td_event_emptyset (&events);
 549   td_ta_set_event_p (thread_agent, &events);
 550
 551   /* Delete thread event breakpoints, if any.  */
 552   remove_thread_event_breakpoints ();
 553   td_create_bp_addr = 0;
 554   td_death_bp_addr = 0;
 555 }
 556
 557 static void
 558 check_thread_signals (void)
 559 {
 560 #ifdef GET_THREAD_SIGNALS
 561   if (!thread_signals)
 562     {
 563       sigset_t mask;
 564       int i;
 565
 566       GET_THREAD_SIGNALS (&mask);
 567       sigemptyset (&thread_stop_set);
 568       sigemptyset (&thread_print_set);
 569
 570       for (i = 1; i < NSIG; i++)
 571         {
 572           if (sigismember (&mask, i))
 573             {
 574               if (signal_stop_update (target_signal_from_host (i), 0))
 575                 sigaddset (&thread_stop_set, i);
 576               if (signal_print_update (target_signal_from_host (i), 0))
 577                 sigaddset (&thread_print_set, i);
 578               thread_signals = 1;
 579             }
 580         }
 581     }
 582 #endif
 583 }
 584
 585 static void
 586 disable_thread_signals (void)
 587 {
 588 #ifdef GET_THREAD_SIGNALS
 589   if (thread_signals)
 590     {
 591       int i;
 592
 593       for (i = 1; i < NSIG; i++)
 594         {
 595           if (sigismember (&thread_stop_set, i))
 596             signal_stop_update (target_signal_from_host (i), 1);
 597           if (sigismember (&thread_print_set, i))
 598             signal_print_update (target_signal_from_host (i), 1);
 599         }
 600
 601       thread_signals = 0;
 602     }
 603 #endif
 604 }
 605
 606 static void
 607 thread_db_new_objfile (struct objfile *objfile)
 608 {
 609   td_err_e err;
 610
 611   /* First time through, report that libthread_db was successfuly
 612      loaded.  Can't print this in in thread_db_load as, at that stage,
 613      the interpreter and it's console haven't started.  The real
 614      problem here is that libthread_db is loaded too early - it should
 615      only be loaded when there is a program to debug.  */
 616   {
 617     static int dejavu;
 618     if (!dejavu)
 619       {
 620         Dl_info info;
 621         const char *library = NULL;
 622         /* Try dladdr.  */
 623         if (dladdr ((*td_ta_new_p), &info) != 0)
 624           library = info.dli_fname;
 625         /* Try dlinfo?  */
 626         if (library == NULL)
 627           /* Paranoid - don't let a NULL path slip through.  */
 628           library = LIBTHREAD_DB_SO;
 629         printf_unfiltered ("Using host libthread_db library \"%s\".\n",
 630                            library);
 631         dejavu = 1;
 632       }
 633   }
 634
 635   /* Don't attempt to use thread_db on targets which can not run
 636      (core files).  */
 637   if (objfile == NULL || !target_has_execution)
 638     {
 639       /* All symbols have been discarded.  If the thread_db target is
 640          active, deactivate it now.  */
 641       if (using_thread_db)
 642         {
 643           gdb_assert (proc_handle.pid == 0);
 644           unpush_target (&thread_db_ops);
 645           using_thread_db = 0;
 646         }
 647
 648       keep_thread_db = 0;
 649
 650       goto quit;
 651     }
 652
 653   if (using_thread_db)
 654     /* Nothing to do.  The thread library was already detected and the
 655        target vector was already activated.  */
 656     goto quit;
 657
 658   /* Initialize the structure that identifies the child process.  Note
 659      that at this point there is no guarantee that we actually have a
 660      child process.  */
 661   proc_handle.pid = GET_PID (inferior_ptid);
 662
 663   /* Now attempt to open a connection to the thread library.  */
 664   err = td_ta_new_p (&proc_handle, &thread_agent);
 665   switch (err)
 666     {
 667     case TD_NOLIBTHREAD:
 668       /* No thread library was detected.  */
 669       break;
 670
 671     case TD_OK:
 672       printf_unfiltered ("[Thread debugging using libthread_db enabled]\n");
 673
 674       /* The thread library was detected.  Activate the thread_db target.  */
 675       push_target (&thread_db_ops);
 676       using_thread_db = 1;
 677
 678       /* If the thread library was detected in the main symbol file
 679          itself, we assume that the program was statically linked
 680          against the thread library and well have to keep this
 681          module's target vector activated until forever...  Well, at
 682          least until all symbols have been discarded anyway (see
 683          above).  */
 684       if (objfile == symfile_objfile)
 685         {
 686           gdb_assert (proc_handle.pid == 0);
 687           keep_thread_db = 1;
 688         }
 689
 690       /* We can only poke around if there actually is a child process.
 691          If there is no child process alive, postpone the steps below
 692          until one has been created.  */
 693       if (proc_handle.pid != 0)
 694         {
 695           enable_thread_event_reporting ();
 696           thread_db_find_new_threads ();
 697         }
 698       break;
 699
 700     default:
 701       warning ("Cannot initialize thread debugging library: %s",
 702                thread_db_err_str (err));
 703       break;
 704     }
 705
 706 quit:
 707   if (target_new_objfile_chain)
 708     target_new_objfile_chain (objfile);
 709 }
 710
 711 static void
 712 attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
 713                const td_thrinfo_t *ti_p, int verbose)
 714 {
 715   struct thread_info *tp;
 716   td_err_e err;
 717
 718   check_thread_signals ();
 719
 720   /* Add the thread to GDB's thread list.  */
 721   tp = add_thread (ptid);
 722   tp->private = xmalloc (sizeof (struct private_thread_info));
 723   memset (tp->private, 0, sizeof (struct private_thread_info));
 724
 725   if (verbose)
 726     printf_unfiltered ("[New %s]\n", target_pid_to_str (ptid));
 727
 728   if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE)
 729     return;                     /* A zombie thread -- do not attach.  */
 730
 731   /* Under GNU/Linux, we have to attach to each and every thread.  */
 732 #ifdef ATTACH_LWP
 733   ATTACH_LWP (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)), 0);
 734 #endif
 735
 736   /* Enable thread event reporting for this thread.  */
 737   err = td_thr_event_enable_p (th_p, 1);
 738   if (err != TD_OK)
 739     error ("Cannot enable thread event reporting for %s: %s",
 740            target_pid_to_str (ptid), thread_db_err_str (err));
 741 }
 742
 743 static void
 744 thread_db_attach (char *args, int from_tty)
 745 {
 746   target_beneath->to_attach (args, from_tty);
 747
 748   /* Destroy thread info; it's no longer valid.  */
 749   init_thread_list ();
 750
 751   /* The child process is now the actual multi-threaded
 752      program.  Snatch its process ID...  */
 753   proc_handle.pid = GET_PID (inferior_ptid);
 754
 755   /* ...and perform the remaining initialization steps.  */
 756   enable_thread_event_reporting ();
 757   thread_db_find_new_threads ();
 758 }
 759
 760 static void
 761 detach_thread (ptid_t ptid, int verbose)
 762 {
 763   if (verbose)
 764     printf_unfiltered ("[%s exited]\n", target_pid_to_str (ptid));
 765 }
 766
 767 static void
 768 thread_db_detach (char *args, int from_tty)
 769 {
 770   disable_thread_event_reporting ();
 771
 772   /* There's no need to save & restore inferior_ptid here, since the
 773      inferior is supposed to be survive this function call.  */
 774   inferior_ptid = lwp_from_thread (inferior_ptid);
 775
 776   /* Forget about the child's process ID.  We shouldn't need it
 777      anymore.  */
 778   proc_handle.pid = 0;
 779
 780   target_beneath->to_detach (args, from_tty);
 781 }
 782
 783 static int
 784 clear_lwpid_callback (struct thread_info *thread, void *dummy)
 785 {
 786   /* If we know that our thread implementation is 1-to-1, we could save
 787      a certain amount of information; it's not clear how much, so we
 788      are always conservative.  */
 789
 790   thread->private->th_valid = 0;
 791   thread->private->ti_valid = 0;
 792
 793   return 0;
 794 }
 795
 796 static void
 797 thread_db_resume (ptid_t ptid, int step, enum target_signal signo)
 798 {
 799   struct cleanup *old_chain = save_inferior_ptid ();
 800
 801   if (GET_PID (ptid) == -1)
 802     inferior_ptid = lwp_from_thread (inferior_ptid);
 803   else if (is_thread (ptid))
 804     ptid = lwp_from_thread (ptid);
 805
 806   /* Clear cached data which may not be valid after the resume.  */
 807   iterate_over_threads (clear_lwpid_callback, NULL);
 808
 809   target_beneath->to_resume (ptid, step, signo);
 810
 811   do_cleanups (old_chain);
 812 }
 813
 814 /* Check if PID is currently stopped at the location of a thread event
 815    breakpoint location.  If it is, read the event message and act upon
 816    the event.  */
 817
 818 static void
 819 check_event (ptid_t ptid)
 820 {
 821   td_event_msg_t msg;
 822   td_thrinfo_t ti;
 823   td_err_e err;
 824   CORE_ADDR stop_pc;
 825   int loop = 0;
 826
 827   /* Bail out early if we're not at a thread event breakpoint.  */
 828   stop_pc = read_pc_pid (ptid) - DECR_PC_AFTER_BREAK;
 829   if (stop_pc != td_create_bp_addr && stop_pc != td_death_bp_addr)
 830     return;
 831
 832   /* If we are at a create breakpoint, we do not know what new lwp
 833      was created and cannot specifically locate the event message for it.
 834      We have to call td_ta_event_getmsg() to get
 835      the latest message.  Since we have no way of correlating whether
 836      the event message we get back corresponds to our breakpoint, we must
 837      loop and read all event messages, processing them appropriately.
 838      This guarantees we will process the correct message before continuing
 839      from the breakpoint.
 840
 841      Currently, death events are not enabled.  If they are enabled,
 842      the death event can use the td_thr_event_getmsg() interface to
 843      get the message specifically for that lwp and avoid looping
 844      below.  */
 845
 846   loop = 1;
 847
 848   do
 849     {
 850       err = td_ta_event_getmsg_p (thread_agent, &msg);
 851       if (err != TD_OK)
 852         {
 853           if (err == TD_NOMSG)
 854             return;
 855
 856           error ("Cannot get thread event message: %s",
 857                  thread_db_err_str (err));
 858         }
 859
 860       err = td_thr_get_info_p (msg.th_p, &ti);
 861       if (err != TD_OK)
 862         error ("Cannot get thread info: %s", thread_db_err_str (err));
 863
 864       ptid = BUILD_THREAD (ti.ti_tid, GET_PID (ptid));
 865
 866       switch (msg.event)
 867         {
 868         case TD_CREATE:
 869
 870           /* We may already know about this thread, for instance when the
 871              user has issued the `info threads' command before the SIGTRAP
 872              for hitting the thread creation breakpoint was reported.  */
 873           if (!in_thread_list (ptid))
 874             attach_thread (ptid, msg.th_p, &ti, 1);
 875
 876           break;
 877
 878         case TD_DEATH:
 879
 880           if (!in_thread_list (ptid))
 881             error ("Spurious thread death event.");
 882
 883           detach_thread (ptid, 1);
 884
 885           break;
 886
 887         default:
 888           error ("Spurious thread event.");
 889         }
 890     }
 891   while (loop);
 892 }
 893
 894 static ptid_t
 895 thread_db_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
 896 {
 897   extern ptid_t trap_ptid;
 898
 899   if (GET_PID (ptid) != -1 && is_thread (ptid))
 900     ptid = lwp_from_thread (ptid);
 901
 902   ptid = target_beneath->to_wait (ptid, ourstatus);
 903
 904   if (proc_handle.pid == 0)
 905     /* The current child process isn't the actual multi-threaded
 906        program yet, so don't try to do any special thread-specific
 907        post-processing and bail out early.  */
 908     return ptid;
 909
 910   if (ourstatus->kind == TARGET_WAITKIND_EXITED)
 911     return pid_to_ptid (-1);
 912
 913   if (ourstatus->kind == TARGET_WAITKIND_STOPPED
 914       && ourstatus->value.sig == TARGET_SIGNAL_TRAP)
 915     /* Check for a thread event.  */
 916     check_event (ptid);
 917
 918   if (!ptid_equal (trap_ptid, null_ptid))
 919     trap_ptid = thread_from_lwp (trap_ptid);
 920
 921   return thread_from_lwp (ptid);
 922 }
 923
 924 static int
 925 thread_db_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
 926                        struct mem_attrib *attrib, struct target_ops *target)
 927 {
 928   struct cleanup *old_chain = save_inferior_ptid ();
 929   int xfer;
 930
 931   if (is_thread (inferior_ptid))
 932     {
 933       /* FIXME: This seems to be necessary to make sure breakpoints
 934          are removed.  */
 935       if (!target_thread_alive (inferior_ptid))
 936         inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid));
 937       else
 938         inferior_ptid = lwp_from_thread (inferior_ptid);
 939     }
 940
 941   xfer =
 942     target_beneath->to_xfer_memory (memaddr, myaddr, len, write, attrib,
 943                                     target);
 944
 945   do_cleanups (old_chain);
 946   return xfer;
 947 }
 948
 949 static void
 950 thread_db_fetch_registers (int regno)
 951 {
 952   struct thread_info *thread_info;
 953   prgregset_t gregset;
 954   gdb_prfpregset_t fpregset;
 955   td_err_e err;
 956
 957   if (!is_thread (inferior_ptid))
 958     {
 959       /* Pass the request to the target beneath us.  */
 960       target_beneath->to_fetch_registers (regno);
 961       return;
 962     }
 963
 964   thread_info = find_thread_pid (inferior_ptid);
 965   thread_db_map_id2thr (thread_info, 1);
 966
 967   err = td_thr_getgregs_p (&thread_info->private->th, gregset);
 968   if (err != TD_OK)
 969     error ("Cannot fetch general-purpose registers for thread %ld: %s",
 970            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
 971
 972   err = td_thr_getfpregs_p (&thread_info->private->th, &fpregset);
 973   if (err != TD_OK)
 974     error ("Cannot get floating-point registers for thread %ld: %s",
 975            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
 976
 977   /* Note that we must call supply_gregset after calling the thread_db
 978      routines because the thread_db routines call ps_lgetgregs and
 979      friends which clobber GDB's register cache.  */
 980   supply_gregset ((gdb_gregset_t *) gregset);
 981   supply_fpregset (&fpregset);
 982 }
 983
 984 static void
 985 thread_db_store_registers (int regno)
 986 {
 987   prgregset_t gregset;
 988   gdb_prfpregset_t fpregset;
 989   td_err_e err;
 990   struct thread_info *thread_info;
 991
 992   if (!is_thread (inferior_ptid))
 993     {
 994       /* Pass the request to the target beneath us.  */
 995       target_beneath->to_store_registers (regno);
 996       return;
 997     }
 998
 999   thread_info = find_thread_pid (inferior_ptid);
1000   thread_db_map_id2thr (thread_info, 1);
1001
1002   if (regno != -1)
1003     {
1004       char raw[MAX_REGISTER_SIZE];
1005
1006       deprecated_read_register_gen (regno, raw);
1007       thread_db_fetch_registers (-1);
1008       supply_register (regno, raw);
1009     }
1010
1011   fill_gregset ((gdb_gregset_t *) gregset, -1);
1012   fill_fpregset (&fpregset, -1);
1013
1014   err = td_thr_setgregs_p (&thread_info->private->th, gregset);
1015   if (err != TD_OK)
1016     error ("Cannot store general-purpose registers for thread %ld: %s",
1017            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
1018   err = td_thr_setfpregs_p (&thread_info->private->th, &fpregset);
1019   if (err != TD_OK)
1020     error ("Cannot store floating-point registers  for thread %ld: %s",
1021            (long) GET_THREAD (inferior_ptid), thread_db_err_str (err));
1022 }
1023
1024 static void
1025 thread_db_kill (void)
1026 {
1027   /* There's no need to save & restore inferior_ptid here, since the
1028      inferior isn't supposed to survive this function call.  */
1029   inferior_ptid = lwp_from_thread (inferior_ptid);
1030   target_beneath->to_kill ();
1031 }
1032
1033 static void
1034 thread_db_create_inferior (char *exec_file, char *allargs, char **env)
1035 {
1036   if (!keep_thread_db)
1037     {
1038       unpush_target (&thread_db_ops);
1039       using_thread_db = 0;
1040     }
1041
1042   target_beneath->to_create_inferior (exec_file, allargs, env);
1043 }
1044
1045 static void
1046 thread_db_post_startup_inferior (ptid_t ptid)
1047 {
1048   if (proc_handle.pid == 0)
1049     {
1050       /* The child process is now the actual multi-threaded
1051          program.  Snatch its process ID...  */
1052       proc_handle.pid = GET_PID (ptid);
1053
1054       /* ...and perform the remaining initialization steps.  */
1055       enable_thread_event_reporting ();
1056       thread_db_find_new_threads ();
1057     }
1058 }
1059
1060 static void
1061 thread_db_mourn_inferior (void)
1062 {
1063   remove_thread_event_breakpoints ();
1064
1065   /* Forget about the child's process ID.  We shouldn't need it
1066      anymore.  */
1067   proc_handle.pid = 0;
1068
1069   target_beneath->to_mourn_inferior ();
1070
1071   /* Detach thread_db target ops if not dealing with a statically
1072      linked threaded program.  This allows a corefile to be debugged
1073      after finishing debugging of a threaded program.  At present,
1074      debugging a statically-linked threaded program is broken, but
1075      the check is added below in the event that it is fixed in the
1076      future.  */
1077   if (!keep_thread_db)
1078     {
1079       unpush_target (&thread_db_ops);
1080       using_thread_db = 0;
1081     }
1082 }
1083
1084 static int
1085 thread_db_thread_alive (ptid_t ptid)
1086 {
1087   td_thrhandle_t th;
1088   td_err_e err;
1089
1090   if (is_thread (ptid))
1091     {
1092       struct thread_info *thread_info;
1093       thread_info = find_thread_pid (ptid);
1094
1095       thread_db_map_id2thr (thread_info, 0);
1096       if (!thread_info->private->th_valid)
1097         return 0;
1098
1099       err = td_thr_validate_p (&thread_info->private->th);
1100       if (err != TD_OK)
1101         return 0;
1102
1103       if (!thread_info->private->ti_valid)
1104         {
1105           err =
1106             td_thr_get_info_p (&thread_info->private->th,
1107                                &thread_info->private->ti);
1108           if (err != TD_OK)
1109             return 0;
1110           thread_info->private->ti_valid = 1;
1111         }
1112
1113       if (thread_info->private->ti.ti_state == TD_THR_UNKNOWN
1114           || thread_info->private->ti.ti_state == TD_THR_ZOMBIE)
1115         return 0;               /* A zombie thread.  */
1116
1117       return 1;
1118     }
1119
1120   if (target_beneath->to_thread_alive)
1121     return target_beneath->to_thread_alive (ptid);
1122
1123   return 0;
1124 }
1125
1126 static int
1127 find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
1128 {
1129   td_thrinfo_t ti;
1130   td_err_e err;
1131   ptid_t ptid;
1132
1133   err = td_thr_get_info_p (th_p, &ti);
1134   if (err != TD_OK)
1135     error ("find_new_threads_callback: cannot get thread info: %s",
1136            thread_db_err_str (err));
1137
1138   if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
1139     return 0;                   /* A zombie -- ignore.  */
1140
1141   ptid = BUILD_THREAD (ti.ti_tid, GET_PID (inferior_ptid));
1142
1143   if (!in_thread_list (ptid))
1144     attach_thread (ptid, th_p, &ti, 1);
1145
1146   return 0;
1147 }
1148
1149 static void
1150 thread_db_find_new_threads (void)
1151 {
1152   td_err_e err;
1153
1154   /* Iterate over all user-space threads to discover new threads.  */
1155   err = td_ta_thr_iter_p (thread_agent, find_new_threads_callback, NULL,
1156                           TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
1157                           TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
1158   if (err != TD_OK)
1159     error ("Cannot find new threads: %s", thread_db_err_str (err));
1160 }
1161
1162 static char *
1163 thread_db_pid_to_str (ptid_t ptid)
1164 {
1165   if (is_thread (ptid))
1166     {
1167       static char buf[64];
1168       td_thrinfo_t *ti_p;
1169       td_err_e err;
1170       struct thread_info *thread_info;
1171
1172       thread_info = find_thread_pid (ptid);
1173       thread_db_map_id2thr (thread_info, 0);
1174       if (!thread_info->private->th_valid)
1175         {
1176           snprintf (buf, sizeof (buf), "Thread %ld (Missing)",
1177                     GET_THREAD (ptid));
1178           return buf;
1179         }
1180
1181       ti_p = thread_db_get_info (thread_info);
1182
1183       if (ti_p->ti_state == TD_THR_ACTIVE && ti_p->ti_lid != 0)
1184         {
1185           snprintf (buf, sizeof (buf), "Thread %ld (LWP %d)",
1186                     (long) ti_p->ti_tid, ti_p->ti_lid);
1187         }
1188       else
1189         {
1190           snprintf (buf, sizeof (buf), "Thread %ld (%s)",
1191                     (long) ti_p->ti_tid,
1192                     thread_db_state_str (ti_p->ti_state));
1193         }
1194
1195       return buf;
1196     }
1197
1198   if (target_beneath->to_pid_to_str (ptid))
1199     return target_beneath->to_pid_to_str (ptid);
1200
1201   return normal_pid_to_str (ptid);
1202 }
1203
1204 /* Get the address of the thread local variable in OBJFILE which is
1205    stored at OFFSET within the thread local storage for thread PTID.  */
1206
1207 static CORE_ADDR
1208 thread_db_get_thread_local_address (ptid_t ptid, struct objfile *objfile,
1209                                     CORE_ADDR offset)
1210 {
1211   if (is_thread (ptid))
1212     {
1213       int objfile_is_library = (objfile->flags & OBJF_SHARED);
1214       td_err_e err;
1215       void *address;
1216       CORE_ADDR lm;
1217       struct thread_info *thread_info;
1218
1219       /* glibc doesn't provide the needed interface.  */
1220       if (!td_thr_tls_get_addr_p)
1221         error ("Cannot find thread-local variables in this thread library.");
1222
1223       /* Get the address of the link map for this objfile.  */
1224       lm = svr4_fetch_objfile_link_map (objfile);
1225
1226       /* Whoops, we couldn't find one. Bail out.  */
1227       if (!lm)
1228         {
1229           if (objfile_is_library)
1230             error ("Cannot find shared library `%s' link_map in dynamic"
1231                    " linker's module list", objfile->name);
1232           else
1233             error ("Cannot find executable file `%s' link_map in dynamic"
1234                    " linker's module list", objfile->name);
1235         }
1236
1237       /* Get info about the thread.  */
1238       thread_info = find_thread_pid (ptid);
1239       thread_db_map_id2thr (thread_info, 1);
1240
1241       /* Finally, get the address of the variable.  */
1242       err = td_thr_tls_get_addr_p (&thread_info->private->th, (void *) lm,
1243                                    offset, &address);
1244
1245 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1246       /* The memory hasn't been allocated, yet.  */
1247       if (err == TD_NOTALLOC)
1248         {
1249           /* Now, if libthread_db provided the initialization image's
1250              address, we *could* try to build a non-lvalue value from
1251              the initialization image.  */
1252           if (objfile_is_library)
1253             error ("The inferior has not yet allocated storage for"
1254                    " thread-local variables in\n"
1255                    "the shared library `%s'\n"
1256                    "for the thread %ld",
1257                    objfile->name, (long) GET_THREAD (ptid));
1258           else
1259             error ("The inferior has not yet allocated storage for"
1260                    " thread-local variables in\n"
1261                    "the executable `%s'\n"
1262                    "for the thread %ld",
1263                    objfile->name, (long) GET_THREAD (ptid));
1264         }
1265 #endif
1266
1267       /* Something else went wrong.  */
1268       if (err != TD_OK)
1269         {
1270           if (objfile_is_library)
1271             error ("Cannot find thread-local storage for thread %ld, "
1272                    "shared library %s:\n%s",
1273                    (long) GET_THREAD (ptid),
1274                    objfile->name, thread_db_err_str (err));
1275           else
1276             error ("Cannot find thread-local storage for thread %ld, "
1277                    "executable file %s:\n%s",
1278                    (long) GET_THREAD (ptid),
1279                    objfile->name, thread_db_err_str (err));
1280         }
1281
1282       /* Cast assuming host == target.  Joy.  */
1283       return (CORE_ADDR) address;
1284     }
1285
1286   if (target_beneath->to_get_thread_local_address)
1287     return target_beneath->to_get_thread_local_address (ptid, objfile,
1288                                                         offset);
1289
1290   error ("Cannot find thread-local values on this target.");
1291 }
1292
1293 static void
1294 init_thread_db_ops (void)
1295 {
1296   thread_db_ops.to_shortname = "multi-thread";
1297   thread_db_ops.to_longname = "multi-threaded child process.";
1298   thread_db_ops.to_doc = "Threads and pthreads support.";
1299   thread_db_ops.to_attach = thread_db_attach;
1300   thread_db_ops.to_detach = thread_db_detach;
1301   thread_db_ops.to_resume = thread_db_resume;
1302   thread_db_ops.to_wait = thread_db_wait;
1303   thread_db_ops.to_fetch_registers = thread_db_fetch_registers;
1304   thread_db_ops.to_store_registers = thread_db_store_registers;
1305   thread_db_ops.to_xfer_memory = thread_db_xfer_memory;
1306   thread_db_ops.to_kill = thread_db_kill;
1307   thread_db_ops.to_create_inferior = thread_db_create_inferior;
1308   thread_db_ops.to_post_startup_inferior = thread_db_post_startup_inferior;
1309   thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior;
1310   thread_db_ops.to_thread_alive = thread_db_thread_alive;
1311   thread_db_ops.to_find_new_threads = thread_db_find_new_threads;
1312   thread_db_ops.to_pid_to_str = thread_db_pid_to_str;
1313   thread_db_ops.to_stratum = thread_stratum;
1314   thread_db_ops.to_has_thread_control = tc_schedlock;
1315   thread_db_ops.to_get_thread_local_address
1316     = thread_db_get_thread_local_address;
1317   thread_db_ops.to_magic = OPS_MAGIC;
1318 }
1319
1320 void
1321 _initialize_thread_db (void)
1322 {
1323   /* Only initialize the module if we can load libthread_db.  */
1324   if (thread_db_load ())
1325     {
1326       init_thread_db_ops ();
1327       add_target (&thread_db_ops);
1328
1329       /* Add ourselves to objfile event chain.  */
1330       target_new_objfile_chain = target_new_objfile_hook;
1331       target_new_objfile_hook = thread_db_new_objfile;
1332     }
1333 }