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   /* One more thread.  */
 226   atomic_increment (&__nptl_nthreads);
 227
 228   struct pthread *pd = (struct pthread *) arg;
 229
 230 #if HP_TIMING_AVAIL
 231   /* Remember the time when the thread was started.  */
 232   hp_timing_t now;
 233   HP_TIMING_NOW (now);
 234   THREAD_SETMEM (pd, cpuclock_offset, now);
 235 #endif
 236
 237   /* Initialize resolver state pointer.  */
 238   __resp = &pd->res;
 239
 240   /* This is where the try/finally block should be created.  For
 241      compilers without that support we do use setjmp.  */
 242   struct pthread_unwind_buf unwind_buf;
 243
 244   /* No previous handlers.  */
 245   unwind_buf.priv.data.prev = NULL;
 246   unwind_buf.priv.data.cleanup = NULL;
 247
 248   int not_first_call;
 249   not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
 250   if (__builtin_expect (! not_first_call, 1))
 251     {
 252       /* Store the new cleanup handler info.  */
 253       THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
 254
 255       if (__builtin_expect (pd->stopped_start, 0))
 256         {
 257           int oldtype = CANCEL_ASYNC ();
 258
 259           /* Get the lock the parent locked to force synchronization.  */
 260           lll_lock (pd->lock);
 261           /* And give it up right away.  */
 262           lll_unlock (pd->lock);
 263
 264           CANCEL_RESET (oldtype);
 265         }
 266
 267       /* Run the code the user provided.  */
 268 #ifdef CALL_THREAD_FCT
 269       THREAD_SETMEM (pd, result, CALL_THREAD_FCT (pd));
 270 #else
 271       THREAD_SETMEM (pd, result, pd->start_routine (pd->arg));
 272 #endif
 273     }
 274
 275   /* Run the destructor for the thread-local data.  */
 276   __nptl_deallocate_tsd ();
 277
 278   /* Clean up any state libc stored in thread-local variables.  */
 279   __libc_thread_freeres ();
 280
 281   /* If this is the last thread we terminate the process now.  We
 282      do not notify the debugger, it might just irritate it if there
 283      is no thread left.  */
 284   if (__builtin_expect (atomic_decrement_and_test (&__nptl_nthreads), 0))
 285     /* This was the last thread.  */
 286     exit (0);
 287
 288   /* Report the death of the thread if this is wanted.  */
 289   if (__builtin_expect (pd->report_events, 0))
 290     {
 291       /* See whether TD_DEATH is in any of the mask.  */
 292       const int idx = __td_eventword (TD_DEATH);
 293       const uint32_t mask = __td_eventmask (TD_DEATH);
 294
 295       if ((mask & (__nptl_threads_events.event_bits[idx]
 296                    | pd->eventbuf.eventmask.event_bits[idx])) != 0)
 297         {
 298           /* Yep, we have to signal the death.  Add the descriptor to
 299              the list but only if it is not already on it.  */
 300           if (pd->nextevent == NULL)
 301             {
 302               pd->eventbuf.eventnum = TD_DEATH;
 303               pd->eventbuf.eventdata = pd;
 304
 305               do
 306                 pd->nextevent = __nptl_last_event;
 307               while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
 308                                                            pd, pd->nextevent));
 309             }
 310
 311           /* Now call the function to signal the event.  */
 312           __nptl_death_event ();
 313         }
 314     }
 315
 316   /* The thread is exiting now.  Don't set this bit until after we've hit
 317      the event-reporting breakpoint, so that td_thr_get_info on us while at
 318      the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE.  */
 319   atomic_bit_set (&pd->cancelhandling, EXITING_BIT);
 320
 321   /* If the thread is detached free the TCB.  */
 322   if (IS_DETACHED (pd))
 323     /* Free the TCB.  */
 324     __free_tcb (pd);
 325
 326   /* We cannot call '_exit' here.  '_exit' will terminate the process.
 327
 328      The 'exit' implementation in the kernel will signal when the
 329      process is really dead since 'clone' got passed the CLONE_CLEARTID
 330      flag.  The 'tid' field in the TCB will be set to zero.
 331
 332      The exit code is zero since in case all threads exit by calling
 333      'pthread_exit' the exit status must be 0 (zero).  */
 334   __exit_thread_inline (0);
 335
 336   /* NOTREACHED */
 337   return 0;
 338 }
 339
 340
 341 /* Default thread attributes for the case when the user does not
 342    provide any.  */
 343 static const struct pthread_attr default_attr =
 344   {
 345     /* Just some value > 0 which gets rounded to the nearest page size.  */
 346     .guardsize = 1,
 347   };
 348
 349
 350 int
 351 __pthread_create_2_1 (newthread, attr, start_routine, arg)
 352      pthread_t *newthread;
 353      const pthread_attr_t *attr;
 354      void *(*start_routine) (void *);
 355      void *arg;
 356 {
 357   STACK_VARIABLES;
 358   const struct pthread_attr *iattr;
 359   struct pthread *pd;
 360   int err;
 361
 362   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   err = ALLOCATE_STACK (iattr, &pd);
 369   if (__builtin_expect (err != 0, 0))
 370     /* Something went wrong.  Maybe a parameter of the attributes is
 371        invalid or we could not allocate memory.  */
 372     return err;
 373
 374
 375   /* Initialize the TCB.  All initializations with zero should be
 376      performed in 'get_cached_stack'.  This way we avoid doing this if
 377      the stack freshly allocated with 'mmap'.  */
 378
 379 #ifdef TLS_TCB_AT_TP
 380   /* Reference to the TCB itself.  */
 381   pd->header.self = pd;
 382
 383   /* Self-reference for TLS.  */
 384   pd->header.tcb = pd;
 385 #endif
 386
 387   /* Store the address of the start routine and the parameter.  Since
 388      we do not start the function directly the stillborn thread will
 389      get the information from its thread descriptor.  */
 390   pd->start_routine = start_routine;
 391   pd->arg = arg;
 392
 393   /* Copy the thread attribute flags.  */
 394   struct pthread *self = THREAD_SELF;
 395   pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
 396                | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));
 397
 398   /* Initialize the field for the ID of the thread which is waiting
 399      for us.  This is a self-reference in case the thread is created
 400      detached.  */
 401   pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;
 402
 403   /* The debug events are inherited from the parent.  */
 404   pd->eventbuf = self->eventbuf;
 405
 406
 407   /* Copy the parent's scheduling parameters.  The flags will say what
 408      is valid and what is not.  */
 409   pd->schedpolicy = self->schedpolicy;
 410   pd->schedparam = self->schedparam;
 411
 412   /* Determine scheduling parameters for the thread.  */
 413   if (attr != NULL
 414       && __builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0)
 415       && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0)
 416     {
 417       INTERNAL_SYSCALL_DECL (err);
 418
 419       /* Use the scheduling parameters the user provided.  */
 420       if (iattr->flags & ATTR_FLAG_POLICY_SET)
 421         pd->schedpolicy = iattr->schedpolicy;
 422       else if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
 423         {
 424           pd->schedpolicy = INTERNAL_SYSCALL (sched_getscheduler, err, 1, 0);
 425           pd->flags |= ATTR_FLAG_POLICY_SET;
 426         }
 427
 428       if (iattr->flags & ATTR_FLAG_SCHED_SET)
 429         memcpy (&pd->schedparam, &iattr->schedparam,
 430                 sizeof (struct sched_param));
 431       else if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
 432         {
 433           INTERNAL_SYSCALL (sched_getparam, err, 2, 0, &pd->schedparam);
 434           pd->flags |= ATTR_FLAG_SCHED_SET;
 435         }
 436
 437       /* Check for valid priorities.  */
 438       int minprio = INTERNAL_SYSCALL (sched_get_priority_min, err, 1,
 439                                       iattr->schedpolicy);
 440       int maxprio = INTERNAL_SYSCALL (sched_get_priority_max, err, 1,
 441                                       iattr->schedpolicy);
 442       if (pd->schedparam.sched_priority < minprio
 443           || pd->schedparam.sched_priority > maxprio)
 444         {
 445           err = EINVAL;
 446           goto errout;
 447         }
 448     }
 449
 450   /* Pass the descriptor to the caller.  */
 451   *newthread = (pthread_t) pd;
 452
 453   /* Remember whether the thread is detached or not.  In case of an
 454      error we have to free the stacks of non-detached stillborn
 455      threads.  */
 456   bool is_detached = IS_DETACHED (pd);
 457
 458   /* Start the thread.  */
 459   err = create_thread (pd, iattr, STACK_VARIABLES_ARGS);
 460   if (err != 0)
 461     {
 462     errout:
 463       /* Something went wrong.  Free the resources.  */
 464       if (!is_detached)
 465         __deallocate_stack (pd);
 466       return err;
 467     }
 468
 469   return 0;
 470 }
 471 versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
 472
 473
 474 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
 475 int
 476 __pthread_create_2_0 (newthread, attr, start_routine, arg)
 477      pthread_t *newthread;
 478      const pthread_attr_t *attr;
 479      void *(*start_routine) (void *);
 480      void *arg;
 481 {
 482   /* The ATTR attribute is not really of type `pthread_attr_t *'.  It has
 483      the old size and access to the new members might crash the program.
 484      We convert the struct now.  */
 485   struct pthread_attr new_attr;
 486
 487   if (attr != NULL)
 488     {
 489       struct pthread_attr *iattr = (struct pthread_attr *) attr;
 490       size_t ps = __getpagesize ();
 491
 492       /* Copy values from the user-provided attributes.  */
 493       new_attr.schedparam = iattr->schedparam;
 494       new_attr.schedpolicy = iattr->schedpolicy;
 495       new_attr.flags = iattr->flags;
 496
 497       /* Fill in default values for the fields not present in the old
 498          implementation.  */
 499       new_attr.guardsize = ps;
 500       new_attr.stackaddr = NULL;
 501       new_attr.stacksize = 0;
 502       new_attr.cpuset = NULL;
 503
 504       /* We will pass this value on to the real implementation.  */
 505       attr = (pthread_attr_t *) &new_attr;
 506     }
 507
 508   return __pthread_create_2_1 (newthread, attr, start_routine, arg);
 509 }
 510 compat_symbol (libpthread, __pthread_create_2_0, pthread_create,
 511                GLIBC_2_0);
 512 #endif
 513 \f
 514 /* Information for libthread_db.  */
 515
 516 #include "../nptl_db/db_info.c"