nptl/pthread_create.c

   1 /* Copyright (C) 2002, 2003, 2004, 2005 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 the thread is detached free the TCB.  */
 314   if (IS_DETACHED (pd))
 315     /* Free the TCB.  */
 316     __free_tcb (pd);
 317   else if (__builtin_expect (pd->cancelhandling & SETXID_BITMASK, 0))
 318     {
 319       /* Some other thread might call any of the setXid functions and expect
 320          us to reply.  In this case wait until we did that.  */
 321       do
 322         lll_futex_wait (&pd->setxid_futex, 0);
 323       while (pd->cancelhandling & SETXID_BITMASK);
 324
 325       /* Reset the value so that the stack can be reused.  */
 326       pd->setxid_futex = 0;
 327     }
 328
 329   /* We cannot call '_exit' here.  '_exit' will terminate the process.
 330
 331      The 'exit' implementation in the kernel will signal when the
 332      process is really dead since 'clone' got passed the CLONE_CLEARTID
 333      flag.  The 'tid' field in the TCB will be set to zero.
 334
 335      The exit code is zero since in case all threads exit by calling
 336      'pthread_exit' the exit status must be 0 (zero).  */
 337   __exit_thread_inline (0);
 338
 339   /* NOTREACHED */
 340   return 0;
 341 }
 342
 343
 344 /* Default thread attributes for the case when the user does not
 345    provide any.  */
 346 static const struct pthread_attr default_attr =
 347   {
 348     /* Just some value > 0 which gets rounded to the nearest page size.  */
 349     .guardsize = 1,
 350   };
 351
 352
 353 int
 354 __pthread_create_2_1 (newthread, attr, start_routine, arg)
 355      pthread_t *newthread;
 356      const pthread_attr_t *attr;
 357      void *(*start_routine) (void *);
 358      void *arg;
 359 {
 360   STACK_VARIABLES;
 361
 362   const struct pthread_attr *iattr = (struct pthread_attr *) attr;
 363   if (iattr == NULL)
 364     /* Is this the best idea?  On NUMA machines this could mean
 365        accessing far-away memory.  */
 366     iattr = &default_attr;
 367
 368   struct pthread *pd = NULL;
 369   int err = ALLOCATE_STACK (iattr, &pd);
 370   if (__builtin_expect (err != 0, 0))
 371     /* Something went wrong.  Maybe a parameter of the attributes is
 372        invalid or we could not allocate memory.  */
 373     return err;
 374
 375
 376   /* Initialize the TCB.  All initializations with zero should be
 377      performed in 'get_cached_stack'.  This way we avoid doing this if
 378      the stack freshly allocated with 'mmap'.  */
 379
 380 #ifdef TLS_TCB_AT_TP
 381   /* Reference to the TCB itself.  */
 382   pd->header.self = pd;
 383
 384   /* Self-reference for TLS.  */
 385   pd->header.tcb = pd;
 386 #endif
 387
 388   /* Store the address of the start routine and the parameter.  Since
 389      we do not start the function directly the stillborn thread will
 390      get the information from its thread descriptor.  */
 391   pd->start_routine = start_routine;
 392   pd->arg = arg;
 393
 394   /* Copy the thread attribute flags.  */
 395   struct pthread *self = THREAD_SELF;
 396   pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
 397                | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));
 398
 399   /* Initialize the field for the ID of the thread which is waiting
 400      for us.  This is a self-reference in case the thread is created
 401      detached.  */
 402   pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;
 403
 404   /* The debug events are inherited from the parent.  */
 405   pd->eventbuf = self->eventbuf;
 406
 407
 408   /* Copy the parent's scheduling parameters.  The flags will say what
 409      is valid and what is not.  */
 410   pd->schedpolicy = self->schedpolicy;
 411   pd->schedparam = self->schedparam;
 412
 413   /* Copy the stack guard canary.  */
 414 #ifdef THREAD_COPY_STACK_GUARD
 415   THREAD_COPY_STACK_GUARD (pd);
 416 #endif
 417
 418   /* Determine scheduling parameters for the thread.  */
 419   if (attr != NULL
 420       && __builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0)
 421       && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0)
 422     {
 423       INTERNAL_SYSCALL_DECL (scerr);
 424
 425       /* Use the scheduling parameters the user provided.  */
 426       if (iattr->flags & ATTR_FLAG_POLICY_SET)
 427         pd->schedpolicy = iattr->schedpolicy;
 428       else if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
 429         {
 430           pd->schedpolicy = INTERNAL_SYSCALL (sched_getscheduler, scerr, 1, 0);
 431           pd->flags |= ATTR_FLAG_POLICY_SET;
 432         }
 433
 434       if (iattr->flags & ATTR_FLAG_SCHED_SET)
 435         memcpy (&pd->schedparam, &iattr->schedparam,
 436                 sizeof (struct sched_param));
 437       else if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
 438         {
 439           INTERNAL_SYSCALL (sched_getparam, scerr, 2, 0, &pd->schedparam);
 440           pd->flags |= ATTR_FLAG_SCHED_SET;
 441         }
 442
 443       /* Check for valid priorities.  */
 444       int minprio = INTERNAL_SYSCALL (sched_get_priority_min, scerr, 1,
 445                                       iattr->schedpolicy);
 446       int maxprio = INTERNAL_SYSCALL (sched_get_priority_max, scerr, 1,
 447                                       iattr->schedpolicy);
 448       if (pd->schedparam.sched_priority < minprio
 449           || pd->schedparam.sched_priority > maxprio)
 450         {
 451           err = EINVAL;
 452           goto errout;
 453         }
 454     }
 455
 456   /* Pass the descriptor to the caller.  */
 457   *newthread = (pthread_t) pd;
 458
 459   /* Remember whether the thread is detached or not.  In case of an
 460      error we have to free the stacks of non-detached stillborn
 461      threads.  */
 462   bool is_detached = IS_DETACHED (pd);
 463
 464   /* Start the thread.  */
 465   err = create_thread (pd, iattr, STACK_VARIABLES_ARGS);
 466   if (err != 0)
 467     {
 468       /* Something went wrong.  Free the resources.  */
 469       if (!is_detached)
 470         {
 471         errout:
 472           __deallocate_stack (pd);
 473         }
 474       return err;
 475     }
 476
 477   return 0;
 478 }
 479 versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
 480
 481
 482 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
 483 int
 484 __pthread_create_2_0 (newthread, attr, start_routine, arg)
 485      pthread_t *newthread;
 486      const pthread_attr_t *attr;
 487      void *(*start_routine) (void *);
 488      void *arg;
 489 {
 490   /* The ATTR attribute is not really of type `pthread_attr_t *'.  It has
 491      the old size and access to the new members might crash the program.
 492      We convert the struct now.  */
 493   struct pthread_attr new_attr;
 494
 495   if (attr != NULL)
 496     {
 497       struct pthread_attr *iattr = (struct pthread_attr *) attr;
 498       size_t ps = __getpagesize ();
 499
 500       /* Copy values from the user-provided attributes.  */
 501       new_attr.schedparam = iattr->schedparam;
 502       new_attr.schedpolicy = iattr->schedpolicy;
 503       new_attr.flags = iattr->flags;
 504
 505       /* Fill in default values for the fields not present in the old
 506          implementation.  */
 507       new_attr.guardsize = ps;
 508       new_attr.stackaddr = NULL;
 509       new_attr.stacksize = 0;
 510       new_attr.cpuset = NULL;
 511
 512       /* We will pass this value on to the real implementation.  */
 513       attr = (pthread_attr_t *) &new_attr;
 514     }
 515
 516   return __pthread_create_2_1 (newthread, attr, start_routine, arg);
 517 }
 518 compat_symbol (libpthread, __pthread_create_2_0, pthread_create,
 519                GLIBC_2_0);
 520 #endif
 521 \f
 522 /* Information for libthread_db.  */
 523
 524 #include "../nptl_db/db_info.c"
 525 \f
 526 /* If pthread_create is present, libgcc_eh.a and libsupc++.a expects some other POSIX thread
 527    functions to be present as well.  */
 528 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_lock)
 529 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_unlock)
 530
 531 PTHREAD_STATIC_FN_REQUIRE (pthread_once)
 532 PTHREAD_STATIC_FN_REQUIRE (pthread_cancel)
 533
 534 PTHREAD_STATIC_FN_REQUIRE (pthread_key_create)
 535 PTHREAD_STATIC_FN_REQUIRE (pthread_setspecific)
 536 PTHREAD_STATIC_FN_REQUIRE (pthread_getspecific)