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