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       /* Queue the stack memory block for reuse and exit the process.  The
 210          kernel will signal via writing to the address returned by
 211          QUEUE-STACK when the stack is available.  */
 212       __deallocate_stack (pd);
 213     }
 214 }
 215
 216
 217 static int
 218 start_thread (void *arg)
 219 {
 220   struct pthread *pd = (struct pthread *) arg;
 221
 222 #if HP_TIMING_AVAIL
 223   /* Remember the time when the thread was started.  */
 224   hp_timing_t now;
 225   HP_TIMING_NOW (now);
 226   THREAD_SETMEM (pd, cpuclock_offset, now);
 227 #endif
 228
 229   /* Initialize resolver state pointer.  */
 230   __resp = &pd->res;
 231
 232 #ifdef __NR_set_robust_list
 233 # ifndef __ASSUME_SET_ROBUST_LIST
 234   if (__set_robust_list_avail >= 0)
 235 # endif
 236     {
 237       INTERNAL_SYSCALL_DECL (err);
 238       /* This call should never fail because the initial call in init.c
 239          succeeded.  */
 240       INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 241                         sizeof (struct robust_list_head));
 242     }
 243 #endif
 244
 245   /* This is where the try/finally block should be created.  For
 246      compilers without that support we do use setjmp.  */
 247   struct pthread_unwind_buf unwind_buf;
 248
 249   /* No previous handlers.  */
 250   unwind_buf.priv.data.prev = NULL;
 251   unwind_buf.priv.data.cleanup = NULL;
 252
 253   int not_first_call;
 254   not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
 255   if (__builtin_expect (! not_first_call, 1))
 256     {
 257       /* Store the new cleanup handler info.  */
 258       THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
 259
 260       if (__builtin_expect (pd->stopped_start, 0))
 261         {
 262           int oldtype = CANCEL_ASYNC ();
 263
 264           /* Get the lock the parent locked to force synchronization.  */
 265           lll_lock (pd->lock);
 266           /* And give it up right away.  */
 267           lll_unlock (pd->lock);
 268
 269           CANCEL_RESET (oldtype);
 270         }
 271
 272       /* Run the code the user provided.  */
 273 #ifdef CALL_THREAD_FCT
 274       THREAD_SETMEM (pd, result, CALL_THREAD_FCT (pd));
 275 #else
 276       THREAD_SETMEM (pd, result, pd->start_routine (pd->arg));
 277 #endif
 278     }
 279
 280   /* Run the destructor for the thread-local data.  */
 281   __nptl_deallocate_tsd ();
 282
 283   /* Clean up any state libc stored in thread-local variables.  */
 284   __libc_thread_freeres ();
 285
 286   /* If this is the last thread we terminate the process now.  We
 287      do not notify the debugger, it might just irritate it if there
 288      is no thread left.  */
 289   if (__builtin_expect (atomic_decrement_and_test (&__nptl_nthreads), 0))
 290     /* This was the last thread.  */
 291     exit (0);
 292
 293   /* Report the death of the thread if this is wanted.  */
 294   if (__builtin_expect (pd->report_events, 0))
 295     {
 296       /* See whether TD_DEATH is in any of the mask.  */
 297       const int idx = __td_eventword (TD_DEATH);
 298       const uint32_t mask = __td_eventmask (TD_DEATH);
 299
 300       if ((mask & (__nptl_threads_events.event_bits[idx]
 301                    | pd->eventbuf.eventmask.event_bits[idx])) != 0)
 302         {
 303           /* Yep, we have to signal the death.  Add the descriptor to
 304              the list but only if it is not already on it.  */
 305           if (pd->nextevent == NULL)
 306             {
 307               pd->eventbuf.eventnum = TD_DEATH;
 308               pd->eventbuf.eventdata = pd;
 309
 310               do
 311                 pd->nextevent = __nptl_last_event;
 312               while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
 313                                                            pd, pd->nextevent));
 314             }
 315
 316           /* Now call the function to signal the event.  */
 317           __nptl_death_event ();
 318         }
 319     }
 320
 321   /* The thread is exiting now.  Don't set this bit until after we've hit
 322      the event-reporting breakpoint, so that td_thr_get_info on us while at
 323      the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE.  */
 324   atomic_bit_set (&pd->cancelhandling, EXITING_BIT);
 325
 326 #ifndef __ASSUME_SET_ROBUST_LIST
 327   /* If this thread has any robust mutexes locked, handle them now.  */
 328 # if __WORDSIZE == 64
 329   void *robust = pd->robust_head.list;
 330 # else
 331   __pthread_slist_t *robust = pd->robust_list.__next;
 332 # endif
 333 /* We let the kernel do the notification if it is able to do so.  */
 334   if (__set_robust_list_avail < 0
 335       && __builtin_expect (robust != &pd->robust_head, 0))
 336     {
 337       do
 338         {
 339           struct __pthread_mutex_s *this = (struct __pthread_mutex_s *)
 340             ((char *) robust - offsetof (struct __pthread_mutex_s,
 341                                          __list.__next));
 342           robust = *((void **) robust);
 343
 344 # ifdef __PTHREAD_MUTEX_HAVE_PREV
 345           this->__list.__prev = NULL;
 346 # endif
 347           this->__list.__next = NULL;
 348
 349           lll_robust_mutex_dead (this->__lock);
 350         }
 351       while (robust != &pd->robust_head);
 352     }
 353 #endif
 354
 355   /* If the thread is detached free the TCB.  */
 356   if (IS_DETACHED (pd))
 357     /* Free the TCB.  */
 358     __free_tcb (pd);
 359   else if (__builtin_expect (pd->cancelhandling & SETXID_BITMASK, 0))
 360     {
 361       /* Some other thread might call any of the setXid functions and expect
 362          us to reply.  In this case wait until we did that.  */
 363       do
 364         lll_futex_wait (&pd->setxid_futex, 0);
 365       while (pd->cancelhandling & SETXID_BITMASK);
 366
 367       /* Reset the value so that the stack can be reused.  */
 368       pd->setxid_futex = 0;
 369     }
 370
 371   /* We cannot call '_exit' here.  '_exit' will terminate the process.
 372
 373      The 'exit' implementation in the kernel will signal when the
 374      process is really dead since 'clone' got passed the CLONE_CLEARTID
 375      flag.  The 'tid' field in the TCB will be set to zero.
 376
 377      The exit code is zero since in case all threads exit by calling
 378      'pthread_exit' the exit status must be 0 (zero).  */
 379   __exit_thread_inline (0);
 380
 381   /* NOTREACHED */
 382   return 0;
 383 }
 384
 385
 386 /* Default thread attributes for the case when the user does not
 387    provide any.  */
 388 static const struct pthread_attr default_attr =
 389   {
 390     /* Just some value > 0 which gets rounded to the nearest page size.  */
 391     .guardsize = 1,
 392   };
 393
 394
 395 int
 396 __pthread_create_2_1 (newthread, attr, start_routine, arg)
 397      pthread_t *newthread;
 398      const pthread_attr_t *attr;
 399      void *(*start_routine) (void *);
 400      void *arg;
 401 {
 402   STACK_VARIABLES;
 403
 404   const struct pthread_attr *iattr = (struct pthread_attr *) attr;
 405   if (iattr == NULL)
 406     /* Is this the best idea?  On NUMA machines this could mean
 407        accessing far-away memory.  */
 408     iattr = &default_attr;
 409
 410   struct pthread *pd = NULL;
 411   int err = ALLOCATE_STACK (iattr, &pd);
 412   if (__builtin_expect (err != 0, 0))
 413     /* Something went wrong.  Maybe a parameter of the attributes is
 414        invalid or we could not allocate memory.  */
 415     return err;
 416
 417
 418   /* Initialize the TCB.  All initializations with zero should be
 419      performed in 'get_cached_stack'.  This way we avoid doing this if
 420      the stack freshly allocated with 'mmap'.  */
 421
 422 #ifdef TLS_TCB_AT_TP
 423   /* Reference to the TCB itself.  */
 424   pd->header.self = pd;
 425
 426   /* Self-reference for TLS.  */
 427   pd->header.tcb = pd;
 428 #endif
 429
 430   /* Store the address of the start routine and the parameter.  Since
 431      we do not start the function directly the stillborn thread will
 432      get the information from its thread descriptor.  */
 433   pd->start_routine = start_routine;
 434   pd->arg = arg;
 435
 436   /* Copy the thread attribute flags.  */
 437   struct pthread *self = THREAD_SELF;
 438   pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
 439                | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));
 440
 441   /* Initialize the field for the ID of the thread which is waiting
 442      for us.  This is a self-reference in case the thread is created
 443      detached.  */
 444   pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;
 445
 446   /* The debug events are inherited from the parent.  */
 447   pd->eventbuf = self->eventbuf;
 448
 449
 450   /* Copy the parent's scheduling parameters.  The flags will say what
 451      is valid and what is not.  */
 452   pd->schedpolicy = self->schedpolicy;
 453   pd->schedparam = self->schedparam;
 454
 455   /* Copy the stack guard canary.  */
 456 #ifdef THREAD_COPY_STACK_GUARD
 457   THREAD_COPY_STACK_GUARD (pd);
 458 #endif
 459
 460   /* Copy the pointer guard value.  */
 461 #ifdef THREAD_COPY_POINTER_GUARD
 462   THREAD_COPY_POINTER_GUARD (pd);
 463 #endif
 464
 465   /* Determine scheduling parameters for the thread.  */
 466   if (attr != NULL
 467       && __builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0)
 468       && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0)
 469     {
 470       INTERNAL_SYSCALL_DECL (scerr);
 471
 472       /* Use the scheduling parameters the user provided.  */
 473       if (iattr->flags & ATTR_FLAG_POLICY_SET)
 474         pd->schedpolicy = iattr->schedpolicy;
 475       else if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
 476         {
 477           pd->schedpolicy = INTERNAL_SYSCALL (sched_getscheduler, scerr, 1, 0);
 478           pd->flags |= ATTR_FLAG_POLICY_SET;
 479         }
 480
 481       if (iattr->flags & ATTR_FLAG_SCHED_SET)
 482         memcpy (&pd->schedparam, &iattr->schedparam,
 483                 sizeof (struct sched_param));
 484       else if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
 485         {
 486           INTERNAL_SYSCALL (sched_getparam, scerr, 2, 0, &pd->schedparam);
 487           pd->flags |= ATTR_FLAG_SCHED_SET;
 488         }
 489
 490       /* Check for valid priorities.  */
 491       int minprio = INTERNAL_SYSCALL (sched_get_priority_min, scerr, 1,
 492                                       iattr->schedpolicy);
 493       int maxprio = INTERNAL_SYSCALL (sched_get_priority_max, scerr, 1,
 494                                       iattr->schedpolicy);
 495       if (pd->schedparam.sched_priority < minprio
 496           || pd->schedparam.sched_priority > maxprio)
 497         {
 498           err = EINVAL;
 499           goto errout;
 500         }
 501     }
 502
 503   /* Pass the descriptor to the caller.  */
 504   *newthread = (pthread_t) pd;
 505
 506   /* Remember whether the thread is detached or not.  In case of an
 507      error we have to free the stacks of non-detached stillborn
 508      threads.  */
 509   bool is_detached = IS_DETACHED (pd);
 510
 511   /* Start the thread.  */
 512   err = create_thread (pd, iattr, STACK_VARIABLES_ARGS);
 513   if (err != 0)
 514     {
 515       /* Something went wrong.  Free the resources.  */
 516       if (!is_detached)
 517         {
 518         errout:
 519           __deallocate_stack (pd);
 520         }
 521       return err;
 522     }
 523
 524   return 0;
 525 }
 526 versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
 527
 528
 529 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
 530 int
 531 __pthread_create_2_0 (newthread, attr, start_routine, arg)
 532      pthread_t *newthread;
 533      const pthread_attr_t *attr;
 534      void *(*start_routine) (void *);
 535      void *arg;
 536 {
 537   /* The ATTR attribute is not really of type `pthread_attr_t *'.  It has
 538      the old size and access to the new members might crash the program.
 539      We convert the struct now.  */
 540   struct pthread_attr new_attr;
 541
 542   if (attr != NULL)
 543     {
 544       struct pthread_attr *iattr = (struct pthread_attr *) attr;
 545       size_t ps = __getpagesize ();
 546
 547       /* Copy values from the user-provided attributes.  */
 548       new_attr.schedparam = iattr->schedparam;
 549       new_attr.schedpolicy = iattr->schedpolicy;
 550       new_attr.flags = iattr->flags;
 551
 552       /* Fill in default values for the fields not present in the old
 553          implementation.  */
 554       new_attr.guardsize = ps;
 555       new_attr.stackaddr = NULL;
 556       new_attr.stacksize = 0;
 557       new_attr.cpuset = NULL;
 558
 559       /* We will pass this value on to the real implementation.  */
 560       attr = (pthread_attr_t *) &new_attr;
 561     }
 562
 563   return __pthread_create_2_1 (newthread, attr, start_routine, arg);
 564 }
 565 compat_symbol (libpthread, __pthread_create_2_0, pthread_create,
 566                GLIBC_2_0);
 567 #endif
 568 \f
 569 /* Information for libthread_db.  */
 570
 571 #include "../nptl_db/db_info.c"
 572 \f
 573 /* If pthread_create is present, libgcc_eh.a and libsupc++.a expects some other POSIX thread
 574    functions to be present as well.  */
 575 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_lock)
 576 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_unlock)
 577
 578 PTHREAD_STATIC_FN_REQUIRE (pthread_once)
 579 PTHREAD_STATIC_FN_REQUIRE (pthread_cancel)
 580
 581 PTHREAD_STATIC_FN_REQUIRE (pthread_key_create)
 582 PTHREAD_STATIC_FN_REQUIRE (pthread_setspecific)
 583 PTHREAD_STATIC_FN_REQUIRE (pthread_getspecific)