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glibc  2.9
Functions | Variables
pthread_create.c File Reference
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "pthreadP.h"
#include <hp-timing.h>
#include <ldsodefs.h>
#include <atomic.h>
#include <libc-internal.h>
#include <resolv.h>
#include <kernel-features.h>
#include <shlib-compat.h>
#include "allocatestack.c"
#include <createthread.c>
#include "../nptl_db/db_info.c"

Go to the source code of this file.

Functions

static int start_thread (void *arg)
struct pthread *internal_function __find_in_stack_list (struct pthread *pd)
void attribute_hidden __nptl_deallocate_tsd (void)
void internal_function __free_tcb (struct pthread *pd)
int __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr, void *(*)(void *) start_routine, void *arg)
 versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1)

Variables

int __pthread_debug
static td_thr_events_t __nptl_threads_events
static struct pthread__nptl_last_event
unsigned int __nptl_nthreads = 1
static struct pthread_attr

Function Documentation

struct pthread* internal_function __find_in_stack_list ( struct pthread pd) [read]

Definition at line 61 of file pthread_create.c.

{
  list_t *entry;
  struct pthread *result = NULL;

  lll_lock (stack_cache_lock, LLL_PRIVATE);

  list_for_each (entry, &stack_used)
    {
      struct pthread *curp;

      curp = list_entry (entry, struct pthread, list);
      if (curp == pd)
       {
         result = curp;
         break;
       }
    }

  if (result == NULL)
    list_for_each (entry, &__stack_user)
      {
       struct pthread *curp;

       curp = list_entry (entry, struct pthread, list);
       if (curp == pd)
         {
           result = curp;
           break;
         }
      }

  lll_unlock (stack_cache_lock, LLL_PRIVATE);

  return result;
}

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void internal_function __free_tcb ( struct pthread pd)

Definition at line 198 of file pthread_create.c.

{
  /* The thread is exiting now.  */
  if (__builtin_expect (atomic_bit_test_set (&pd->cancelhandling,
                                        TERMINATED_BIT) == 0, 1))
    {
      /* Remove the descriptor from the list.  */
      if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
       /* Something is really wrong.  The descriptor for a still
          running thread is gone.  */
       abort ();

      /* Free TPP data.  */
      if (__builtin_expect (pd->tpp != NULL, 0))
       {
         struct priority_protection_data *tpp = pd->tpp;

         pd->tpp = NULL;
         free (tpp);
       }

      /* Queue the stack memory block for reuse and exit the process.  The
        kernel will signal via writing to the address returned by
        QUEUE-STACK when the stack is available.  */
      __deallocate_stack (pd);
    }
}

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Definition at line 103 of file pthread_create.c.

{
  struct pthread *self = THREAD_SELF;

  /* Maybe no data was ever allocated.  This happens often so we have
     a flag for this.  */
  if (THREAD_GETMEM (self, specific_used))
    {
      size_t round;
      size_t cnt;

      round = 0;
      do
       {
         size_t idx;

         /* So far no new nonzero data entry.  */
         THREAD_SETMEM (self, specific_used, false);

         for (cnt = idx = 0; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
           {
             struct pthread_key_data *level2;

             level2 = THREAD_GETMEM_NC (self, specific, cnt);

             if (level2 != NULL)
              {
                size_t inner;

                for (inner = 0; inner < PTHREAD_KEY_2NDLEVEL_SIZE;
                     ++inner, ++idx)
                  {
                    void *data = level2[inner].data;

                    if (data != NULL)
                     {
                       /* Always clear the data.  */
                       level2[inner].data = NULL;

                       /* Make sure the data corresponds to a valid
                          key.  This test fails if the key was
                          deallocated and also if it was
                          re-allocated.  It is the user's
                          responsibility to free the memory in this
                          case.  */
                       if (level2[inner].seq
                           == __pthread_keys[idx].seq
                           /* It is not necessary to register a destructor
                             function.  */
                           && __pthread_keys[idx].destr != NULL)
                         /* Call the user-provided destructor.  */
                         __pthread_keys[idx].destr (data);
                     }
                  }
              }
             else
              idx += PTHREAD_KEY_1STLEVEL_SIZE;
           }

         if (THREAD_GETMEM (self, specific_used) == 0)
           /* No data has been modified.  */
           goto just_free;
       }
      /* We only repeat the process a fixed number of times.  */
      while (__builtin_expect (++round < PTHREAD_DESTRUCTOR_ITERATIONS, 0));

      /* Just clear the memory of the first block for reuse.  */
      memset (&THREAD_SELF->specific_1stblock, '\0',
             sizeof (self->specific_1stblock));

    just_free:
      /* Free the memory for the other blocks.  */
      for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
       {
         struct pthread_key_data *level2;

         level2 = THREAD_GETMEM_NC (self, specific, cnt);
         if (level2 != NULL)
           {
             /* The first block is allocated as part of the thread
               descriptor.  */
             free (level2);
             THREAD_SETMEM_NC (self, specific, cnt, NULL);
           }
       }

      THREAD_SETMEM (self, specific_used, false);
    }
}

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int __pthread_create_2_1 ( pthread_t newthread,
const pthread_attr_t attr,
void *(*) (void *)  start_routine,
void *  arg 
)

Definition at line 421 of file pthread_create.c.

{
  STACK_VARIABLES;

  const struct pthread_attr *iattr = (struct pthread_attr *) attr;
  if (iattr == NULL)
    /* Is this the best idea?  On NUMA machines this could mean
       accessing far-away memory.  */
    iattr = &default_attr;

  struct pthread *pd = NULL;
  int err = ALLOCATE_STACK (iattr, &pd);
  if (__builtin_expect (err != 0, 0))
    /* Something went wrong.  Maybe a parameter of the attributes is
       invalid or we could not allocate memory.  */
    return err;


  /* Initialize the TCB.  All initializations with zero should be
     performed in 'get_cached_stack'.  This way we avoid doing this if
     the stack freshly allocated with 'mmap'.  */

#ifdef TLS_TCB_AT_TP
  /* Reference to the TCB itself.  */
  pd->header.self = pd;

  /* Self-reference for TLS.  */
  pd->header.tcb = pd;
#endif

  /* Store the address of the start routine and the parameter.  Since
     we do not start the function directly the stillborn thread will
     get the information from its thread descriptor.  */
  pd->start_routine = start_routine;
  pd->arg = arg;

  /* Copy the thread attribute flags.  */
  struct pthread *self = THREAD_SELF;
  pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
              | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));

  /* Initialize the field for the ID of the thread which is waiting
     for us.  This is a self-reference in case the thread is created
     detached.  */
  pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;

  /* The debug events are inherited from the parent.  */
  pd->eventbuf = self->eventbuf;


  /* Copy the parent's scheduling parameters.  The flags will say what
     is valid and what is not.  */
  pd->schedpolicy = self->schedpolicy;
  pd->schedparam = self->schedparam;

  /* Copy the stack guard canary.  */
#ifdef THREAD_COPY_STACK_GUARD
  THREAD_COPY_STACK_GUARD (pd);
#endif

  /* Copy the pointer guard value.  */
#ifdef THREAD_COPY_POINTER_GUARD
  THREAD_COPY_POINTER_GUARD (pd);
#endif

  /* Determine scheduling parameters for the thread.  */
  if (attr != NULL
      && __builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0)
      && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0)
    {
      INTERNAL_SYSCALL_DECL (scerr);

      /* Use the scheduling parameters the user provided.  */
      if (iattr->flags & ATTR_FLAG_POLICY_SET)
       pd->schedpolicy = iattr->schedpolicy;
      else if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
       {
         pd->schedpolicy = INTERNAL_SYSCALL (sched_getscheduler, scerr, 1, 0);
         pd->flags |= ATTR_FLAG_POLICY_SET;
       }

      if (iattr->flags & ATTR_FLAG_SCHED_SET)
       memcpy (&pd->schedparam, &iattr->schedparam,
              sizeof (struct sched_param));
      else if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
       {
         INTERNAL_SYSCALL (sched_getparam, scerr, 2, 0, &pd->schedparam);
         pd->flags |= ATTR_FLAG_SCHED_SET;
       }

      /* Check for valid priorities.  */
      int minprio = INTERNAL_SYSCALL (sched_get_priority_min, scerr, 1,
                                  iattr->schedpolicy);
      int maxprio = INTERNAL_SYSCALL (sched_get_priority_max, scerr, 1,
                                  iattr->schedpolicy);
      if (pd->schedparam.sched_priority < minprio
         || pd->schedparam.sched_priority > maxprio)
       {
         err = EINVAL;
         goto errout;
       }
    }

  /* Pass the descriptor to the caller.  */
  *newthread = (pthread_t) pd;

  /* Remember whether the thread is detached or not.  In case of an
     error we have to free the stacks of non-detached stillborn
     threads.  */
  bool is_detached = IS_DETACHED (pd);

  /* Start the thread.  */
  err = create_thread (pd, iattr, STACK_VARIABLES_ARGS);
  if (err != 0)
    {
      /* Something went wrong.  Free the resources.  */
      if (!is_detached)
       {
       errout:
         __deallocate_stack (pd);
       }
      return err;
    }

  return 0;
}

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static int start_thread ( void *  arg) [static]

Definition at line 228 of file pthread_create.c.

{
  struct pthread *pd = (struct pthread *) arg;

#if HP_TIMING_AVAIL
  /* Remember the time when the thread was started.  */
  hp_timing_t now;
  HP_TIMING_NOW (now);
  THREAD_SETMEM (pd, cpuclock_offset, now);
#endif

  /* Initialize resolver state pointer.  */
  __resp = &pd->res;

#ifdef __NR_set_robust_list
# ifndef __ASSUME_SET_ROBUST_LIST
  if (__set_robust_list_avail >= 0)
# endif
    {
      INTERNAL_SYSCALL_DECL (err);
      /* This call should never fail because the initial call in init.c
        succeeded.  */
      INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
                     sizeof (struct robust_list_head));
    }
#endif

  /* If the parent was running cancellation handlers while creating
     the thread the new thread inherited the signal mask.  Reset the
     cancellation signal mask.  */
  if (__builtin_expect (pd->parent_cancelhandling & CANCELING_BITMASK, 0))
    {
      INTERNAL_SYSCALL_DECL (err);
      sigset_t mask;
      __sigemptyset (&mask);
      __sigaddset (&mask, SIGCANCEL);
      (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &mask,
                            NULL, _NSIG / 8);
    }

  /* This is where the try/finally block should be created.  For
     compilers without that support we do use setjmp.  */
  struct pthread_unwind_buf unwind_buf;

  /* No previous handlers.  */
  unwind_buf.priv.data.prev = NULL;
  unwind_buf.priv.data.cleanup = NULL;

  int not_first_call;
  not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
  if (__builtin_expect (! not_first_call, 1))
    {
      /* Store the new cleanup handler info.  */
      THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);

      if (__builtin_expect (pd->stopped_start, 0))
       {
         int oldtype = CANCEL_ASYNC ();

         /* Get the lock the parent locked to force synchronization.  */
         lll_lock (pd->lock, LLL_PRIVATE);
         /* And give it up right away.  */
         lll_unlock (pd->lock, LLL_PRIVATE);

         CANCEL_RESET (oldtype);
       }

      /* Run the code the user provided.  */
#ifdef CALL_THREAD_FCT
      THREAD_SETMEM (pd, result, CALL_THREAD_FCT (pd));
#else
      THREAD_SETMEM (pd, result, pd->start_routine (pd->arg));
#endif
    }

  /* Run the destructor for the thread-local data.  */
  __nptl_deallocate_tsd ();

  /* Clean up any state libc stored in thread-local variables.  */
  __libc_thread_freeres ();

  /* If this is the last thread we terminate the process now.  We
     do not notify the debugger, it might just irritate it if there
     is no thread left.  */
  if (__builtin_expect (atomic_decrement_and_test (&__nptl_nthreads), 0))
    /* This was the last thread.  */
    exit (0);

  /* Report the death of the thread if this is wanted.  */
  if (__builtin_expect (pd->report_events, 0))
    {
      /* See whether TD_DEATH is in any of the mask.  */
      const int idx = __td_eventword (TD_DEATH);
      const uint32_t mask = __td_eventmask (TD_DEATH);

      if ((mask & (__nptl_threads_events.event_bits[idx]
                 | pd->eventbuf.eventmask.event_bits[idx])) != 0)
       {
         /* Yep, we have to signal the death.  Add the descriptor to
            the list but only if it is not already on it.  */
         if (pd->nextevent == NULL)
           {
             pd->eventbuf.eventnum = TD_DEATH;
             pd->eventbuf.eventdata = pd;

             do
              pd->nextevent = __nptl_last_event;
             while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
                                                    pd, pd->nextevent));
           }

         /* Now call the function to signal the event.  */
         __nptl_death_event ();
       }
    }

  /* The thread is exiting now.  Don't set this bit until after we've hit
     the event-reporting breakpoint, so that td_thr_get_info on us while at
     the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE.  */
  atomic_bit_set (&pd->cancelhandling, EXITING_BIT);

#ifndef __ASSUME_SET_ROBUST_LIST
  /* If this thread has any robust mutexes locked, handle them now.  */
# if __WORDSIZE == 64
  void *robust = pd->robust_head.list;
# else
  __pthread_slist_t *robust = pd->robust_list.__next;
# endif
  /* We let the kernel do the notification if it is able to do so.
     If we have to do it here there for sure are no PI mutexes involved
     since the kernel support for them is even more recent.  */
  if (__set_robust_list_avail < 0
      && __builtin_expect (robust != (void *) &pd->robust_head, 0))
    {
      do
       {
         struct __pthread_mutex_s *this = (struct __pthread_mutex_s *)
           ((char *) robust - offsetof (struct __pthread_mutex_s,
                                    __list.__next));
         robust = *((void **) robust);

# ifdef __PTHREAD_MUTEX_HAVE_PREV
         this->__list.__prev = NULL;
# endif
         this->__list.__next = NULL;

         lll_robust_dead (this->__lock, /* XYZ */ LLL_SHARED);
       }
      while (robust != (void *) &pd->robust_head);
    }
#endif

  /* If the thread is detached free the TCB.  */
  if (IS_DETACHED (pd))
    /* Free the TCB.  */
    __free_tcb (pd);
  else if (__builtin_expect (pd->cancelhandling & SETXID_BITMASK, 0))
    {
      /* Some other thread might call any of the setXid functions and expect
        us to reply.  In this case wait until we did that.  */
      do
       lll_futex_wait (&pd->setxid_futex, 0, LLL_PRIVATE);
      while (pd->cancelhandling & SETXID_BITMASK);

      /* Reset the value so that the stack can be reused.  */
      pd->setxid_futex = 0;
    }

  /* We cannot call '_exit' here.  '_exit' will terminate the process.

     The 'exit' implementation in the kernel will signal when the
     process is really dead since 'clone' got passed the CLONE_CLEARTID
     flag.  The 'tid' field in the TCB will be set to zero.

     The exit code is zero since in case all threads exit by calling
     'pthread_exit' the exit status must be 0 (zero).  */
  __exit_thread_inline (0);

  /* NOTREACHED */
  return 0;
}

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versioned_symbol ( libpthread  ,
__pthread_create_2_1  ,
pthread_create  ,
GLIBC_2_1   
)

Variable Documentation

struct pthread* __nptl_last_event [static]

Definition at line 46 of file pthread_create.c.

unsigned int __nptl_nthreads = 1

Definition at line 49 of file pthread_create.c.

Definition at line 43 of file pthread_create.c.

Definition at line 40 of file pthread_create.c.

struct pthread_attr [static]
Initial value:
  {
    
    .guardsize = 1,
  }

Definition at line 413 of file pthread_create.c.