nptl/pthread_create.c

   1 /* Copyright (C) 2002, 2003, 2004 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 /* Table of the key information.  */
  59 struct pthread_key_struct __pthread_keys[PTHREAD_KEYS_MAX]
  60   __attribute__ ((nocommon));
  61 hidden_data_def (__pthread_keys)
  62
  63 struct pthread *
  64 internal_function
  65 __find_in_stack_list (pd)
  66      struct pthread *pd;
  67 {
  68   list_t *entry;
  69   struct pthread *result = NULL;
  70
  71   lll_lock (stack_cache_lock);
  72
  73   list_for_each (entry, &stack_used)
  74     {
  75       struct pthread *curp;
  76
  77       curp = list_entry (entry, struct pthread, list);
  78       if (curp == pd)
  79         {
  80           result = curp;
  81           break;
  82         }
  83     }
  84
  85   if (result == NULL)
  86     list_for_each (entry, &__stack_user)
  87       {
  88         struct pthread *curp;
  89
  90         curp = list_entry (entry, struct pthread, list);
  91         if (curp == pd)
  92           {
  93             result = curp;
  94             break;
  95           }
  96       }
  97
  98   lll_unlock (stack_cache_lock);
  99
 100   return result;
 101 }
 102
 103
 104 /* Deallocate POSIX thread-local-storage.  */
 105 void
 106 attribute_hidden
 107 __nptl_deallocate_tsd (void)
 108 {
 109   struct pthread *self = THREAD_SELF;
 110
 111   /* Maybe no data was ever allocated.  This happens often so we have
 112      a flag for this.  */
 113   if (THREAD_GETMEM (self, specific_used))
 114     {
 115       size_t round;
 116       size_t cnt;
 117
 118       round = 0;
 119       do
 120         {
 121           size_t idx;
 122
 123           /* So far no new nonzero data entry.  */
 124           THREAD_SETMEM (self, specific_used, false);
 125
 126           for (cnt = idx = 0; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
 127             {
 128               struct pthread_key_data *level2;
 129
 130               level2 = THREAD_GETMEM_NC (self, specific, cnt);
 131
 132               if (level2 != NULL)
 133                 {
 134                   size_t inner;
 135
 136                   for (inner = 0; inner < PTHREAD_KEY_2NDLEVEL_SIZE;
 137                        ++inner, ++idx)
 138                     {
 139                       void *data = level2[inner].data;
 140
 141                       if (data != NULL)
 142                         {
 143                           /* Always clear the data.  */
 144                           level2[inner].data = NULL;
 145
 146                           /* Make sure the data corresponds to a valid
 147                              key.  This test fails if the key was
 148                              deallocated and also if it was
 149                              re-allocated.  It is the user's
 150                              responsibility to free the memory in this
 151                              case.  */
 152                           if (level2[inner].seq
 153                               == __pthread_keys[idx].seq
 154                               /* It is not necessary to register a destructor
 155                                  function.  */
 156                               && __pthread_keys[idx].destr != NULL)
 157                             /* Call the user-provided destructor.  */
 158                             __pthread_keys[idx].destr (data);
 159                         }
 160                     }
 161                 }
 162               else
 163                 idx += PTHREAD_KEY_1STLEVEL_SIZE;
 164             }
 165
 166           if (THREAD_GETMEM (self, specific_used) == 0)
 167             /* No data has been modified.  */
 168             goto just_free;
 169         }
 170       /* We only repeat the process a fixed number of times.  */
 171       while (__builtin_expect (++round < PTHREAD_DESTRUCTOR_ITERATIONS, 0));
 172
 173       /* Just clear the memory of the first block for reuse.  */
 174       memset (&THREAD_SELF->specific_1stblock, '\0',
 175               sizeof (self->specific_1stblock));
 176
 177     just_free:
 178       /* Free the memory for the other blocks.  */
 179       for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
 180         {
 181           struct pthread_key_data *level2;
 182
 183           level2 = THREAD_GETMEM_NC (self, specific, cnt);
 184           if (level2 != NULL)
 185             {
 186               /* The first block is allocated as part of the thread
 187                  descriptor.  */
 188               free (level2);
 189               THREAD_SETMEM_NC (self, specific, cnt, NULL);
 190             }
 191         }
 192
 193       THREAD_SETMEM (self, specific_used, false);
 194     }
 195 }
 196
 197
 198 /* Deallocate a thread's stack after optionally making sure the thread
 199    descriptor is still valid.  */
 200 void
 201 internal_function
 202 __free_tcb (struct pthread *pd)
 203 {
 204   /* The thread is exiting now.  */
 205   if (__builtin_expect (atomic_bit_test_set (&pd->cancelhandling,
 206                                              TERMINATED_BIT) == 0, 1))
 207     {
 208       /* Remove the descriptor from the list.  */
 209       if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
 210         /* Something is really wrong.  The descriptor for a still
 211            running thread is gone.  */
 212         abort ();
 213
 214       /* Queue the stack memory block for reuse and exit the process.  The
 215          kernel will signal via writing to the address returned by
 216          QUEUE-STACK when the stack is available.  */
 217       __deallocate_stack (pd);
 218     }
 219 }
 220
 221
 222 static int
 223 start_thread (void *arg)
 224 {
 225   struct pthread *pd = (struct pthread *) arg;
 226
 227 #if HP_TIMING_AVAIL
 228   /* Remember the time when the thread was started.  */
 229   hp_timing_t now;
 230   HP_TIMING_NOW (now);
 231   THREAD_SETMEM (pd, cpuclock_offset, now);
 232 #endif
 233
 234   /* Initialize resolver state pointer.  */
 235   __resp = &pd->res;
 236
 237   /* This is where the try/finally block should be created.  For
 238      compilers without that support we do use setjmp.  */
 239   struct pthread_unwind_buf unwind_buf;
 240
 241   /* No previous handlers.  */
 242   unwind_buf.priv.data.prev = NULL;
 243   unwind_buf.priv.data.cleanup = NULL;
 244
 245   int not_first_call;
 246   not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
 247   if (__builtin_expect (! not_first_call, 1))
 248     {
 249       /* Store the new cleanup handler info.  */
 250       THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
 251
 252       if (__builtin_expect (pd->stopped_start, 0))
 253         {
 254           int oldtype = CANCEL_ASYNC ();
 255
 256           /* Get the lock the parent locked to force synchronization.  */
 257           lll_lock (pd->lock);
 258           /* And give it up right away.  */
 259           lll_unlock (pd->lock);
 260
 261           CANCEL_RESET (oldtype);
 262         }
 263
 264       /* Run the code the user provided.  */
 265 #ifdef CALL_THREAD_FCT
 266       THREAD_SETMEM (pd, result, CALL_THREAD_FCT (pd));
 267 #else
 268       THREAD_SETMEM (pd, result, pd->start_routine (pd->arg));
 269 #endif
 270     }
 271
 272   /* Run the destructor for the thread-local data.  */
 273   __nptl_deallocate_tsd ();
 274
 275   /* Clean up any state libc stored in thread-local variables.  */
 276   __libc_thread_freeres ();
 277
 278   /* If this is the last thread we terminate the process now.  We
 279      do not notify the debugger, it might just irritate it if there
 280      is no thread left.  */
 281   if (__builtin_expect (atomic_decrement_and_test (&__nptl_nthreads), 0))
 282     /* This was the last thread.  */
 283     exit (0);
 284
 285   /* Report the death of the thread if this is wanted.  */
 286   if (__builtin_expect (pd->report_events, 0))
 287     {
 288       /* See whether TD_DEATH is in any of the mask.  */
 289       const int idx = __td_eventword (TD_DEATH);
 290       const uint32_t mask = __td_eventmask (TD_DEATH);
 291
 292       if ((mask & (__nptl_threads_events.event_bits[idx]
 293                    | pd->eventbuf.eventmask.event_bits[idx])) != 0)
 294         {
 295           /* Yep, we have to signal the death.  Add the descriptor to
 296              the list but only if it is not already on it.  */
 297           if (pd->nextevent == NULL)
 298             {
 299               pd->eventbuf.eventnum = TD_DEATH;
 300               pd->eventbuf.eventdata = pd;
 301
 302               do
 303                 pd->nextevent = __nptl_last_event;
 304               while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
 305                                                            pd, pd->nextevent));
 306             }
 307
 308           /* Now call the function to signal the event.  */
 309           __nptl_death_event ();
 310         }
 311     }
 312
 313   /* The thread is exiting now.  Don't set this bit until after we've hit
 314      the event-reporting breakpoint, so that td_thr_get_info on us while at
 315      the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE.  */
 316   atomic_bit_set (&pd->cancelhandling, EXITING_BIT);
 317
 318   /* If the thread is detached free the TCB.  */
 319   if (IS_DETACHED (pd))
 320     /* Free the TCB.  */
 321     __free_tcb (pd);
 322
 323   /* We cannot call '_exit' here.  '_exit' will terminate the process.
 324
 325      The 'exit' implementation in the kernel will signal when the
 326      process is really dead since 'clone' got passed the CLONE_CLEARTID
 327      flag.  The 'tid' field in the TCB will be set to zero.
 328
 329      The exit code is zero since in case all threads exit by calling
 330      'pthread_exit' the exit status must be 0 (zero).  */
 331   __exit_thread_inline (0);
 332
 333   /* NOTREACHED */
 334   return 0;
 335 }
 336
 337
 338 /* Default thread attributes for the case when the user does not
 339    provide any.  */
 340 static const struct pthread_attr default_attr =
 341   {
 342     /* Just some value > 0 which gets rounded to the nearest page size.  */
 343     .guardsize = 1,
 344   };
 345
 346
 347 int
 348 __pthread_create_2_1 (newthread, attr, start_routine, arg)
 349      pthread_t *newthread;
 350      const pthread_attr_t *attr;
 351      void *(*start_routine) (void *);
 352      void *arg;
 353 {
 354   STACK_VARIABLES;
 355   const struct pthread_attr *iattr;
 356   struct pthread *pd;
 357   int err;
 358
 359   iattr = (struct pthread_attr *) attr;
 360   if (iattr == NULL)
 361     /* Is this the best idea?  On NUMA machines this could mean
 362        accessing far-away memory.  */
 363     iattr = &default_attr;
 364
 365   err = ALLOCATE_STACK (iattr, &pd);
 366   if (__builtin_expect (err != 0, 0))
 367     /* Something went wrong.  Maybe a parameter of the attributes is
 368        invalid or we could not allocate memory.  */
 369     return err;
 370
 371
 372   /* Initialize the TCB.  All initializations with zero should be
 373      performed in 'get_cached_stack'.  This way we avoid doing this if
 374      the stack freshly allocated with 'mmap'.  */
 375
 376 #ifdef TLS_TCB_AT_TP
 377   /* Reference to the TCB itself.  */
 378   pd->header.self = pd;
 379
 380   /* Self-reference for TLS.  */
 381   pd->header.tcb = pd;
 382 #endif
 383
 384   /* Store the address of the start routine and the parameter.  Since
 385      we do not start the function directly the stillborn thread will
 386      get the information from its thread descriptor.  */
 387   pd->start_routine = start_routine;
 388   pd->arg = arg;
 389
 390   /* Copy the thread attribute flags.  */
 391   struct pthread *self = THREAD_SELF;
 392   pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
 393                | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));
 394
 395   /* Initialize the field for the ID of the thread which is waiting
 396      for us.  This is a self-reference in case the thread is created
 397      detached.  */
 398   pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;
 399
 400   /* The debug events are inherited from the parent.  */
 401   pd->eventbuf = self->eventbuf;
 402
 403
 404   /* Copy the parent's scheduling parameters.  The flags will say what
 405      is valid and what is not.  */
 406   pd->schedpolicy = self->schedpolicy;
 407   pd->schedparam = self->schedparam;
 408
 409   /* Determine scheduling parameters for the thread.  */
 410   if (attr != NULL
 411       && __builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0)
 412       && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0)
 413     {
 414       INTERNAL_SYSCALL_DECL (err);
 415
 416       /* Use the scheduling parameters the user provided.  */
 417       if (iattr->flags & ATTR_FLAG_POLICY_SET)
 418         pd->schedpolicy = iattr->schedpolicy;
 419       else if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
 420         {
 421           pd->schedpolicy = INTERNAL_SYSCALL (sched_getscheduler, err, 1, 0);
 422           pd->flags |= ATTR_FLAG_POLICY_SET;
 423         }
 424
 425       if (iattr->flags & ATTR_FLAG_SCHED_SET)
 426         memcpy (&pd->schedparam, &iattr->schedparam,
 427                 sizeof (struct sched_param));
 428       else if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
 429         {
 430           INTERNAL_SYSCALL (sched_getparam, err, 2, 0, &pd->schedparam);
 431           pd->flags |= ATTR_FLAG_SCHED_SET;
 432         }
 433
 434       /* Check for valid priorities.  */
 435       int minprio = INTERNAL_SYSCALL (sched_get_priority_min, err, 1,
 436                                       iattr->schedpolicy);
 437       int maxprio = INTERNAL_SYSCALL (sched_get_priority_max, err, 1,
 438                                       iattr->schedpolicy);
 439       if (pd->schedparam.sched_priority < minprio
 440           || pd->schedparam.sched_priority > maxprio)
 441         {
 442           err = EINVAL;
 443           goto errout;
 444         }
 445     }
 446
 447   /* Pass the descriptor to the caller.  */
 448   *newthread = (pthread_t) pd;
 449
 450   /* Remember whether the thread is detached or not.  In case of an
 451      error we have to free the stacks of non-detached stillborn
 452      threads.  */
 453   bool is_detached = IS_DETACHED (pd);
 454
 455   /* Start the thread.  */
 456   err = create_thread (pd, iattr, STACK_VARIABLES_ARGS);
 457   if (err != 0)
 458     {
 459       /* Something went wrong.  Free the resources.  */
 460       if (!is_detached)
 461         {
 462         errout:
 463           __deallocate_stack (pd);
 464         }
 465       return err;
 466     }
 467
 468   return 0;
 469 }
 470 versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
 471
 472
 473 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
 474 int
 475 __pthread_create_2_0 (newthread, attr, start_routine, arg)
 476      pthread_t *newthread;
 477      const pthread_attr_t *attr;
 478      void *(*start_routine) (void *);
 479      void *arg;
 480 {
 481   /* The ATTR attribute is not really of type `pthread_attr_t *'.  It has
 482      the old size and access to the new members might crash the program.
 483      We convert the struct now.  */
 484   struct pthread_attr new_attr;
 485
 486   if (attr != NULL)
 487     {
 488       struct pthread_attr *iattr = (struct pthread_attr *) attr;
 489       size_t ps = __getpagesize ();
 490
 491       /* Copy values from the user-provided attributes.  */
 492       new_attr.schedparam = iattr->schedparam;
 493       new_attr.schedpolicy = iattr->schedpolicy;
 494       new_attr.flags = iattr->flags;
 495
 496       /* Fill in default values for the fields not present in the old
 497          implementation.  */
 498       new_attr.guardsize = ps;
 499       new_attr.stackaddr = NULL;
 500       new_attr.stacksize = 0;
 501       new_attr.cpuset = NULL;
 502
 503       /* We will pass this value on to the real implementation.  */
 504       attr = (pthread_attr_t *) &new_attr;
 505     }
 506
 507   return __pthread_create_2_1 (newthread, attr, start_routine, arg);
 508 }
 509 compat_symbol (libpthread, __pthread_create_2_0, pthread_create,
 510                GLIBC_2_0);
 511 #endif
 512 \f
 513 /* Information for libthread_db.  */
 514
 515 #include "../nptl_db/db_info.c"