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