nptl/pthread_create.c

   1 /* Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <stdbool.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include "pthreadP.h"
  25 #include <hp-timing.h>
  26 #include <ldsodefs.h>
  27 #include <atomic.h>
  28 #include <libc-internal.h>
  29 #include <resolv.h>
  30
  31 #include <shlib-compat.h>
  32
  33
  34 /* Local function to start thread and handle cleanup.  */
  35 static int start_thread (void *arg);
  36
  37
  38 /* Nozero if debugging mode is enabled.  */
  39 int __pthread_debug;
  40
  41 /* Globally enabled events.  */
  42 static td_thr_events_t __nptl_threads_events;
  43
  44 /* Pointer to descriptor with the last event.  */
  45 static struct pthread *__nptl_last_event;
  46
  47 /* Number of threads running.  */
  48 unsigned int __nptl_nthreads = 1;
  49
  50
  51 /* Code to allocate and deallocate a stack.  */
  52 #include "allocatestack.c"
  53
  54 /* Code to create the thread.  */
  55 #include <createthread.c>
  56
  57
  58 struct pthread *
  59 internal_function
  60 __find_in_stack_list (pd)
  61      struct pthread *pd;
  62 {
  63   list_t *entry;
  64   struct pthread *result = NULL;
  65
  66   lll_lock (stack_cache_lock);
  67
  68   list_for_each (entry, &stack_used)
  69     {
  70       struct pthread *curp;
  71
  72       curp = list_entry (entry, struct pthread, list);
  73       if (curp == pd)
  74         {
  75           result = curp;
  76           break;
  77         }
  78     }
  79
  80   if (result == NULL)
  81     list_for_each (entry, &__stack_user)
  82       {
  83         struct pthread *curp;
  84
  85         curp = list_entry (entry, struct pthread, list);
  86         if (curp == pd)
  87           {
  88             result = curp;
  89             break;
  90           }
  91       }
  92
  93   lll_unlock (stack_cache_lock);
  94
  95   return result;
  96 }
  97
  98
  99 /* Deallocate POSIX thread-local-storage.  */
 100 void
 101 attribute_hidden
 102 __nptl_deallocate_tsd (void)
 103 {
 104   struct pthread *self = THREAD_SELF;
 105
 106   /* Maybe no data was ever allocated.  This happens often so we have
 107      a flag for this.  */
 108   if (THREAD_GETMEM (self, specific_used))
 109     {
 110       size_t round;
 111       size_t cnt;
 112
 113       round = 0;
 114       do
 115         {
 116           size_t idx;
 117
 118           /* So far no new nonzero data entry.  */
 119           THREAD_SETMEM (self, specific_used, false);
 120
 121           for (cnt = idx = 0; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
 122             {
 123               struct pthread_key_data *level2;
 124
 125               level2 = THREAD_GETMEM_NC (self, specific, cnt);
 126
 127               if (level2 != NULL)
 128                 {
 129                   size_t inner;
 130
 131                   for (inner = 0; inner < PTHREAD_KEY_2NDLEVEL_SIZE;
 132                        ++inner, ++idx)
 133                     {
 134                       void *data = level2[inner].data;
 135
 136                       if (data != NULL)
 137                         {
 138                           /* Always clear the data.  */
 139                           level2[inner].data = NULL;
 140
 141                           /* Make sure the data corresponds to a valid
 142                              key.  This test fails if the key was
 143                              deallocated and also if it was
 144                              re-allocated.  It is the user's
 145                              responsibility to free the memory in this
 146                              case.  */
 147                           if (level2[inner].seq
 148                               == __pthread_keys[idx].seq
 149                               /* It is not necessary to register a destructor
 150                                  function.  */
 151                               && __pthread_keys[idx].destr != NULL)
 152                             /* Call the user-provided destructor.  */
 153                             __pthread_keys[idx].destr (data);
 154                         }
 155                     }
 156                 }
 157               else
 158                 idx += PTHREAD_KEY_1STLEVEL_SIZE;
 159             }
 160
 161           if (THREAD_GETMEM (self, specific_used) == 0)
 162             /* No data has been modified.  */
 163             goto just_free;
 164         }
 165       /* We only repeat the process a fixed number of times.  */
 166       while (__builtin_expect (++round < PTHREAD_DESTRUCTOR_ITERATIONS, 0));
 167
 168       /* Just clear the memory of the first block for reuse.  */
 169       memset (&THREAD_SELF->specific_1stblock, '\0',
 170               sizeof (self->specific_1stblock));
 171
 172     just_free:
 173       /* Free the memory for the other blocks.  */
 174       for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
 175         {
 176           struct pthread_key_data *level2;
 177
 178           level2 = THREAD_GETMEM_NC (self, specific, cnt);
 179           if (level2 != NULL)
 180             {
 181               /* The first block is allocated as part of the thread
 182                  descriptor.  */
 183               free (level2);
 184               THREAD_SETMEM_NC (self, specific, cnt, NULL);
 185             }
 186         }
 187
 188       THREAD_SETMEM (self, specific_used, false);
 189     }
 190 }
 191
 192
 193 /* Deallocate a thread's stack after optionally making sure the thread
 194    descriptor is still valid.  */
 195 void
 196 internal_function
 197 __free_tcb (struct pthread *pd)
 198 {
 199   /* The thread is exiting now.  */
 200   if (__builtin_expect (atomic_bit_test_set (&pd->cancelhandling,
 201                                              TERMINATED_BIT) == 0, 1))
 202     {
 203       /* Remove the descriptor from the list.  */
 204       if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
 205         /* Something is really wrong.  The descriptor for a still
 206            running thread is gone.  */
 207         abort ();
 208
 209       /* Free TPP data.  */
 210       if (__builtin_expect (pd->tpp != NULL, 0))
 211         {
 212           struct priority_protection_data *tpp = pd->tpp;
 213
 214           pd->tpp = NULL;
 215           free (tpp);
 216         }
 217
 218       /* Queue the stack memory block for reuse and exit the process.  The
 219          kernel will signal via writing to the address returned by
 220          QUEUE-STACK when the stack is available.  */
 221       __deallocate_stack (pd);
 222     }
 223 }
 224
 225
 226 static int
 227 start_thread (void *arg)
 228 {
 229   struct pthread *pd = (struct pthread *) arg;
 230
 231 #if HP_TIMING_AVAIL
 232   /* Remember the time when the thread was started.  */
 233   hp_timing_t now;
 234   HP_TIMING_NOW (now);
 235   THREAD_SETMEM (pd, cpuclock_offset, now);
 236 #endif
 237
 238   /* Initialize resolver state pointer.  */
 239   __resp = &pd->res;
 240
 241 #ifdef __NR_set_robust_list
 242 # ifndef __ASSUME_SET_ROBUST_LIST
 243   if (__set_robust_list_avail >= 0)
 244 # endif
 245     {
 246       INTERNAL_SYSCALL_DECL (err);
 247       /* This call should never fail because the initial call in init.c
 248          succeeded.  */
 249       INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 250                         sizeof (struct robust_list_head));
 251     }
 252 #endif
 253
 254   /* This is where the try/finally block should be created.  For
 255      compilers without that support we do use setjmp.  */
 256   struct pthread_unwind_buf unwind_buf;
 257
 258   /* No previous handlers.  */
 259   unwind_buf.priv.data.prev = NULL;
 260   unwind_buf.priv.data.cleanup = NULL;
 261
 262   int not_first_call;
 263   not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
 264   if (__builtin_expect (! not_first_call, 1))
 265     {
 266       /* Store the new cleanup handler info.  */
 267       THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
 268
 269       if (__builtin_expect (pd->stopped_start, 0))
 270         {
 271           int oldtype = CANCEL_ASYNC ();
 272
 273           /* Get the lock the parent locked to force synchronization.  */
 274           lll_lock (pd->lock);
 275           /* And give it up right away.  */
 276           lll_unlock (pd->lock);
 277
 278           CANCEL_RESET (oldtype);
 279         }
 280
 281       /* Run the code the user provided.  */
 282 #ifdef CALL_THREAD_FCT
 283       THREAD_SETMEM (pd, result, CALL_THREAD_FCT (pd));
 284 #else
 285       THREAD_SETMEM (pd, result, pd->start_routine (pd->arg));
 286 #endif
 287     }
 288
 289   /* Run the destructor for the thread-local data.  */
 290   __nptl_deallocate_tsd ();
 291
 292   /* Clean up any state libc stored in thread-local variables.  */
 293   __libc_thread_freeres ();
 294
 295   /* If this is the last thread we terminate the process now.  We
 296      do not notify the debugger, it might just irritate it if there
 297      is no thread left.  */
 298   if (__builtin_expect (atomic_decrement_and_test (&__nptl_nthreads), 0))
 299     /* This was the last thread.  */
 300     exit (0);
 301
 302   /* Report the death of the thread if this is wanted.  */
 303   if (__builtin_expect (pd->report_events, 0))
 304     {
 305       /* See whether TD_DEATH is in any of the mask.  */
 306       const int idx = __td_eventword (TD_DEATH);
 307       const uint32_t mask = __td_eventmask (TD_DEATH);
 308
 309       if ((mask & (__nptl_threads_events.event_bits[idx]
 310                    | pd->eventbuf.eventmask.event_bits[idx])) != 0)
 311         {
 312           /* Yep, we have to signal the death.  Add the descriptor to
 313              the list but only if it is not already on it.  */
 314           if (pd->nextevent == NULL)
 315             {
 316               pd->eventbuf.eventnum = TD_DEATH;
 317               pd->eventbuf.eventdata = pd;
 318
 319               do
 320                 pd->nextevent = __nptl_last_event;
 321               while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
 322                                                            pd, pd->nextevent));
 323             }
 324
 325           /* Now call the function to signal the event.  */
 326           __nptl_death_event ();
 327         }
 328     }
 329
 330   /* The thread is exiting now.  Don't set this bit until after we've hit
 331      the event-reporting breakpoint, so that td_thr_get_info on us while at
 332      the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE.  */
 333   atomic_bit_set (&pd->cancelhandling, EXITING_BIT);
 334
 335 #ifndef __ASSUME_SET_ROBUST_LIST
 336   /* If this thread has any robust mutexes locked, handle them now.  */
 337 # if __WORDSIZE == 64
 338   void *robust = pd->robust_head.list;
 339 # else
 340   __pthread_slist_t *robust = pd->robust_list.__next;
 341 # endif
 342   /* We let the kernel do the notification if it is able to do so.
 343      If we have to do it here there for sure are no PI mutexes involved
 344      since the kernel support for them is even more recent.  */
 345   if (__set_robust_list_avail < 0
 346       && __builtin_expect (robust != (void *) &pd->robust_head, 0))
 347     {
 348       do
 349         {
 350           struct __pthread_mutex_s *this = (struct __pthread_mutex_s *)
 351             ((char *) robust - offsetof (struct __pthread_mutex_s,
 352                                          __list.__next));
 353           robust = *((void **) robust);
 354
 355 # ifdef __PTHREAD_MUTEX_HAVE_PREV
 356           this->__list.__prev = NULL;
 357 # endif
 358           this->__list.__next = NULL;
 359
 360           lll_robust_mutex_dead (this->__lock);
 361         }
 362       while (robust != (void *) &pd->robust_head);
 363     }
 364 #endif
 365
 366   /* If the thread is detached free the TCB.  */
 367   if (IS_DETACHED (pd))
 368     /* Free the TCB.  */
 369     __free_tcb (pd);
 370   else if (__builtin_expect (pd->cancelhandling & SETXID_BITMASK, 0))
 371     {
 372       /* Some other thread might call any of the setXid functions and expect
 373          us to reply.  In this case wait until we did that.  */
 374       do
 375         lll_futex_wait (&pd->setxid_futex, 0);
 376       while (pd->cancelhandling & SETXID_BITMASK);
 377
 378       /* Reset the value so that the stack can be reused.  */
 379       pd->setxid_futex = 0;
 380     }
 381
 382   /* We cannot call '_exit' here.  '_exit' will terminate the process.
 383
 384      The 'exit' implementation in the kernel will signal when the
 385      process is really dead since 'clone' got passed the CLONE_CLEARTID
 386      flag.  The 'tid' field in the TCB will be set to zero.
 387
 388      The exit code is zero since in case all threads exit by calling
 389      'pthread_exit' the exit status must be 0 (zero).  */
 390   __exit_thread_inline (0);
 391
 392   /* NOTREACHED */
 393   return 0;
 394 }
 395
 396
 397 /* Default thread attributes for the case when the user does not
 398    provide any.  */
 399 static const struct pthread_attr default_attr =
 400   {
 401     /* Just some value > 0 which gets rounded to the nearest page size.  */
 402     .guardsize = 1,
 403   };
 404
 405
 406 int
 407 __pthread_create_2_1 (newthread, attr, start_routine, arg)
 408      pthread_t *newthread;
 409      const pthread_attr_t *attr;
 410      void *(*start_routine) (void *);
 411      void *arg;
 412 {
 413   STACK_VARIABLES;
 414
 415   const struct pthread_attr *iattr = (struct pthread_attr *) attr;
 416   if (iattr == NULL)
 417     /* Is this the best idea?  On NUMA machines this could mean
 418        accessing far-away memory.  */
 419     iattr = &default_attr;
 420
 421   struct pthread *pd = NULL;
 422   int err = ALLOCATE_STACK (iattr, &pd);
 423   if (__builtin_expect (err != 0, 0))
 424     /* Something went wrong.  Maybe a parameter of the attributes is
 425        invalid or we could not allocate memory.  */
 426     return err;
 427
 428
 429   /* Initialize the TCB.  All initializations with zero should be
 430      performed in 'get_cached_stack'.  This way we avoid doing this if
 431      the stack freshly allocated with 'mmap'.  */
 432
 433 #ifdef TLS_TCB_AT_TP
 434   /* Reference to the TCB itself.  */
 435   pd->header.self = pd;
 436
 437   /* Self-reference for TLS.  */
 438   pd->header.tcb = pd;
 439 #endif
 440
 441   /* Store the address of the start routine and the parameter.  Since
 442      we do not start the function directly the stillborn thread will
 443      get the information from its thread descriptor.  */
 444   pd->start_routine = start_routine;
 445   pd->arg = arg;
 446
 447   /* Copy the thread attribute flags.  */
 448   struct pthread *self = THREAD_SELF;
 449   pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
 450                | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));
 451
 452   /* Initialize the field for the ID of the thread which is waiting
 453      for us.  This is a self-reference in case the thread is created
 454      detached.  */
 455   pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;
 456
 457   /* The debug events are inherited from the parent.  */
 458   pd->eventbuf = self->eventbuf;
 459
 460
 461   /* Copy the parent's scheduling parameters.  The flags will say what
 462      is valid and what is not.  */
 463   pd->schedpolicy = self->schedpolicy;
 464   pd->schedparam = self->schedparam;
 465
 466   /* Copy the stack guard canary.  */
 467 #ifdef THREAD_COPY_STACK_GUARD
 468   THREAD_COPY_STACK_GUARD (pd);
 469 #endif
 470
 471   /* Copy the pointer guard value.  */
 472 #ifdef THREAD_COPY_POINTER_GUARD
 473   THREAD_COPY_POINTER_GUARD (pd);
 474 #endif
 475
 476   /* Determine scheduling parameters for the thread.  */
 477   if (attr != NULL
 478       && __builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0)
 479       && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0)
 480     {
 481       INTERNAL_SYSCALL_DECL (scerr);
 482
 483       /* Use the scheduling parameters the user provided.  */
 484       if (iattr->flags & ATTR_FLAG_POLICY_SET)
 485         pd->schedpolicy = iattr->schedpolicy;
 486       else if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
 487         {
 488           pd->schedpolicy = INTERNAL_SYSCALL (sched_getscheduler, scerr, 1, 0);
 489           pd->flags |= ATTR_FLAG_POLICY_SET;
 490         }
 491
 492       if (iattr->flags & ATTR_FLAG_SCHED_SET)
 493         memcpy (&pd->schedparam, &iattr->schedparam,
 494                 sizeof (struct sched_param));
 495       else if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
 496         {
 497           INTERNAL_SYSCALL (sched_getparam, scerr, 2, 0, &pd->schedparam);
 498           pd->flags |= ATTR_FLAG_SCHED_SET;
 499         }
 500
 501       /* Check for valid priorities.  */
 502       int minprio = INTERNAL_SYSCALL (sched_get_priority_min, scerr, 1,
 503                                       iattr->schedpolicy);
 504       int maxprio = INTERNAL_SYSCALL (sched_get_priority_max, scerr, 1,
 505                                       iattr->schedpolicy);
 506       if (pd->schedparam.sched_priority < minprio
 507           || pd->schedparam.sched_priority > maxprio)
 508         {
 509           err = EINVAL;
 510           goto errout;
 511         }
 512     }
 513
 514   /* Pass the descriptor to the caller.  */
 515   *newthread = (pthread_t) pd;
 516
 517   /* Remember whether the thread is detached or not.  In case of an
 518      error we have to free the stacks of non-detached stillborn
 519      threads.  */
 520   bool is_detached = IS_DETACHED (pd);
 521
 522   /* Start the thread.  */
 523   err = create_thread (pd, iattr, STACK_VARIABLES_ARGS);
 524   if (err != 0)
 525     {
 526       /* Something went wrong.  Free the resources.  */
 527       if (!is_detached)
 528         {
 529         errout:
 530           __deallocate_stack (pd);
 531         }
 532       return err;
 533     }
 534
 535   return 0;
 536 }
 537 versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
 538
 539
 540 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
 541 int
 542 __pthread_create_2_0 (newthread, attr, start_routine, arg)
 543      pthread_t *newthread;
 544      const pthread_attr_t *attr;
 545      void *(*start_routine) (void *);
 546      void *arg;
 547 {
 548   /* The ATTR attribute is not really of type `pthread_attr_t *'.  It has
 549      the old size and access to the new members might crash the program.
 550      We convert the struct now.  */
 551   struct pthread_attr new_attr;
 552
 553   if (attr != NULL)
 554     {
 555       struct pthread_attr *iattr = (struct pthread_attr *) attr;
 556       size_t ps = __getpagesize ();
 557
 558       /* Copy values from the user-provided attributes.  */
 559       new_attr.schedparam = iattr->schedparam;
 560       new_attr.schedpolicy = iattr->schedpolicy;
 561       new_attr.flags = iattr->flags;
 562
 563       /* Fill in default values for the fields not present in the old
 564          implementation.  */
 565       new_attr.guardsize = ps;
 566       new_attr.stackaddr = NULL;
 567       new_attr.stacksize = 0;
 568       new_attr.cpuset = NULL;
 569
 570       /* We will pass this value on to the real implementation.  */
 571       attr = (pthread_attr_t *) &new_attr;
 572     }
 573
 574   return __pthread_create_2_1 (newthread, attr, start_routine, arg);
 575 }
 576 compat_symbol (libpthread, __pthread_create_2_0, pthread_create,
 577                GLIBC_2_0);
 578 #endif
 579 \f
 580 /* Information for libthread_db.  */
 581
 582 #include "../nptl_db/db_info.c"
 583 \f
 584 /* If pthread_create is present, libgcc_eh.a and libsupc++.a expects some other POSIX thread
 585    functions to be present as well.  */
 586 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_lock)
 587 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_unlock)
 588
 589 PTHREAD_STATIC_FN_REQUIRE (pthread_once)
 590 PTHREAD_STATIC_FN_REQUIRE (pthread_cancel)
 591
 592 PTHREAD_STATIC_FN_REQUIRE (pthread_key_create)
 593 PTHREAD_STATIC_FN_REQUIRE (pthread_setspecific)
 594 PTHREAD_STATIC_FN_REQUIRE (pthread_getspecific)