source: rtems/cpukit/posix/src/pthread.c @ 2014063

/*
 *  $Id$
 */

#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <limits.h>

#include <rtems/system.h>
#include <rtems/score/apiext.h>
#include <rtems/score/stack.h>
#include <rtems/score/thread.h>
#include <rtems/score/userext.h>
#include <rtems/score/wkspace.h>
#include <rtems/posix/pthread.h>
#include <rtems/posix/priority.h>
#include <rtems/posix/psignal.h>
#include <rtems/posix/config.h>
#include <rtems/posix/key.h>
#include <rtems/posix/time.h>

/*PAGE
 *
 *  The default pthreads attributes structure.
 */
 
const pthread_attr_t _POSIX_Threads_Default_attributes = {
  TRUE,                    /* is_initialized */
  NULL,                    /* stackaddr */
  STACK_MINIMUM_SIZE * 2,  /* stacksize */
  PTHREAD_SCOPE_PROCESS,   /* contentionscope */
  PTHREAD_EXPLICIT_SCHED,  /* inheritsched */
  SCHED_FIFO,              /* schedpolicy */
  {                        /* schedparam */
    128,                   /* sched_priority */
    0,                     /* ss_low_priority */
    { 0L, 0 },             /* ss_replenish_period */
    { 0L, 0 }              /* ss_initial_budget */
  },
  PTHREAD_CREATE_JOINABLE, /* detachstate */
  1                        /* cputime_clock_allowed */
};

/*PAGE
 *
 *  _POSIX_Threads_Sporadic_budget_TSR
 */

void _POSIX_Threads_Sporadic_budget_TSR(
  Objects_Id      id,
  void           *argument
)
{
  unsigned32          ticks;
  unsigned32          new_priority;
  Thread_Control     *the_thread;
  POSIX_API_Control  *api;

  the_thread = argument;

  api = the_thread->API_Extensions[ THREAD_API_POSIX ];

  ticks = _POSIX_Timespec_to_interval( &api->schedparam.ss_initial_budget );

  if ( !ticks )
    ticks = 1;

  the_thread->cpu_time_budget = ticks;
  
  new_priority = _POSIX_Priority_To_core( api->ss_high_priority );
  the_thread->real_priority = new_priority;

  if ( the_thread->resource_count == 0 ||
       the_thread->current_priority > new_priority )
    _Thread_Change_priority( the_thread, new_priority );

  ticks = _POSIX_Timespec_to_interval( &api->schedparam.ss_replenish_period );

  if ( !ticks )
    ticks = 1;

  _Watchdog_Insert_ticks( &api->Sporadic_timer, ticks );
}

/*PAGE
 *
 *  _POSIX_Threads_Sporadic_budget_callout
 */

void _POSIX_Threads_Sporadic_budget_callout(
  Thread_Control *the_thread
)
{
  POSIX_API_Control *api;
  unsigned32         new_priority;

  api = the_thread->API_Extensions[ THREAD_API_POSIX ];

  /*
   *  This will prevent the thread from consuming its entire "budget"
   *  while at low priority.
   */


  the_thread->cpu_time_budget = 0xFFFFFFFF; /* XXX should be based on MAX_U32 */

  new_priority = _POSIX_Priority_To_core( api->schedparam.ss_low_priority );
  the_thread->real_priority = new_priority;

 if ( the_thread->resource_count == 0 ||
      the_thread->current_priority > new_priority )
    _Thread_Change_priority( the_thread, new_priority );
}

/*PAGE
 *
 *  _POSIX_Threads_Create_extension
 *
 *  XXX
 */
 
boolean _POSIX_Threads_Create_extension(
  Thread_Control *executing,
  Thread_Control *created
)
{
  POSIX_API_Control *api;
 
  api = _Workspace_Allocate( sizeof( POSIX_API_Control ) );
 
  if ( !api )
    return FALSE;
 
  created->API_Extensions[ THREAD_API_POSIX ] = api;
 
  /* XXX check all fields are touched */
  api->Attributes  = _POSIX_Threads_Default_attributes;
  api->detachstate = _POSIX_Threads_Default_attributes.detachstate;
  api->schedpolicy = _POSIX_Threads_Default_attributes.schedpolicy;
  api->schedparam  = _POSIX_Threads_Default_attributes.schedparam;
  api->schedparam.sched_priority = 
     _POSIX_Priority_From_core( created->current_priority );
 
  /*
   *  If the thread is not a posix thread, then all posix signals are blocked
   *  by default.
   */

  /* XXX use signal constants */
  api->signals_pending = 0;
  if ( _Objects_Get_class( created->Object.id ) == OBJECTS_POSIX_THREADS )
    api->signals_blocked = 0;
  else
    api->signals_blocked = 0xffffffff;

/* XXX set signal parameters -- block all signals for non-posix threads */

  _Thread_queue_Initialize(
    &api->Join_List,
    OBJECTS_NO_CLASS,                 /* only used for proxy operations */
    THREAD_QUEUE_DISCIPLINE_FIFO,
    STATES_WAITING_FOR_JOIN_AT_EXIT,
    NULL,                             /* no extract proxy handler */
    0
  );
 
  _Watchdog_Initialize(
    &api->Sporadic_timer,
    _POSIX_Threads_Sporadic_budget_TSR,
    created->Object.id,
    created
  );

  return TRUE;
}

/*PAGE
 *
 *  _POSIX_Threads_Delete_extension
 */
 
User_extensions_routine _POSIX_Threads_Delete_extension(
  Thread_Control *executing,
  Thread_Control *deleted
)
{
  Thread_Control     *the_thread;
  POSIX_API_Control  *api;
  void              **value_ptr;

  api = deleted->API_Extensions[ THREAD_API_POSIX ];
 
  /* XXX run cancellation handlers */

  _POSIX_Keys_Run_destructors( deleted );

  /*
   *  Wakeup all the tasks which joined with this one
   */
 
  value_ptr = (void **) deleted->Wait.return_argument;

  while ( (the_thread = _Thread_queue_Dequeue( &api->Join_List )) )
      *(void **)the_thread->Wait.return_argument = value_ptr;
 
  if ( api->schedpolicy == SCHED_SPORADIC )
    (void) _Watchdog_Remove( &api->Sporadic_timer );

  deleted->API_Extensions[ THREAD_API_POSIX ] = NULL;

  (void) _Workspace_Free( api );
}

/*PAGE
 *
 *  _POSIX_Threads_Initialize_user_threads
 *
 *  This routine creates and starts all configured user
 *  initialzation threads.
 *
 *  Input parameters: NONE
 *
 *  Output parameters:  NONE
 */
 
void _POSIX_Threads_Initialize_user_threads( void )
{
  int                                 status;
  unsigned32                          index;
  unsigned32                          maximum;
  posix_initialization_threads_table *user_threads;
  pthread_t                           thread_id;
 
  user_threads = _POSIX_Threads_User_initialization_threads;
  maximum      = _POSIX_Threads_Number_of_initialization_threads;

  if ( !user_threads || maximum == 0 )
    return;
 
  for ( index=0 ; index < maximum ; index++ ) {
    status = pthread_create(
      &thread_id,
      NULL,
      user_threads[ index ].entry,
      NULL
    );
    assert( !status );
  }
}

/*PAGE
 *
 *  API Extension control structures
 */

API_extensions_Control _POSIX_Threads_API_extensions = {
  { NULL, NULL },
  NULL,                                     /* predriver */
  _POSIX_Threads_Initialize_user_threads,   /* postdriver */
  _POSIX_signals_Post_switch_extension,     /* post switch */
};
 
User_extensions_Control _POSIX_Threads_User_extensions = {
  { NULL, NULL },
  { _POSIX_Threads_Create_extension,          /* create */
    NULL,                                     /* start */
    NULL,                                     /* restart */
    _POSIX_Threads_Delete_extension,          /* delete */
    NULL,                                     /* switch */
    NULL,                                     /* begin */
    NULL,                                     /* exitted */
    NULL                                      /* fatal */
  }
};
 
/*PAGE
 *
 *  _POSIX_Threads_Manager_initialization
 *
 *  This routine initializes all threads manager related data structures.
 *
 *  Input parameters:
 *    maximum_pthreads - maximum configured pthreads
 *
 *  Output parameters:  NONE
 */
 
void _POSIX_Threads_Manager_initialization(
  unsigned32                          maximum_pthreads,
  unsigned32                          number_of_initialization_threads,
  posix_initialization_threads_table *user_threads
  
)
{
  _POSIX_Threads_Number_of_initialization_threads = 
                                           number_of_initialization_threads;
  _POSIX_Threads_User_initialization_threads = user_threads;

  /*
   *  There may not be any POSIX initialization threads configured.
   */

#if 0
  if ( user_threads == NULL || number_of_initialization_threads == 0 )
    _Internal_error_Occurred( INTERNAL_ERROR_POSIX_API, TRUE, EINVAL );
#endif

  _Objects_Initialize_information(
    &_POSIX_Threads_Information,
    OBJECTS_POSIX_THREADS,
    FALSE,                               /* does not support global */
    maximum_pthreads,
    sizeof( Thread_Control ),
    TRUE,
    5,                                   /* length is arbitrary for now */
    TRUE                                 /* this class is threads */
  );

  /*
   *  Add all the extensions for this API
   */
 
  _User_extensions_Add_API_set( &_POSIX_Threads_User_extensions );
 
  _API_extensions_Add( &_POSIX_Threads_API_extensions );
 
  /*
   *  If we supported MP, then here we would ...
   *       Register the MP Process Packet routine.
   */
 
}

/*PAGE
 *
 *  3.1.3 Register Fork Handlers, P1003.1c/Draft 10, P1003.1c/Draft 10, p. 27
 *
 *  RTEMS does not support processes, so we fall under this and do not
 *  provide this routine:
 *
 *  "Either the implementation shall support the pthread_atfork() function
 *   as described above or the pthread_atfork() funciton shall not be
 *   provided."
 */

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Attributes, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_setscope(
  pthread_attr_t  *attr,
  int              contentionscope
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  switch ( contentionscope ) {
    case PTHREAD_SCOPE_PROCESS:
      attr->contentionscope = contentionscope;
      return 0;

    case PTHREAD_SCOPE_SYSTEM:
      return ENOSYS;

    default:
      return EINVAL;
  }
}

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Attributes, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_getscope(
  const pthread_attr_t  *attr,
  int                   *contentionscope
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  *contentionscope = attr->contentionscope;
  return 0;
}

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Attributes, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_setinheritsched(
  pthread_attr_t  *attr,
  int              inheritsched
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  switch ( inheritsched ) {
    case PTHREAD_INHERIT_SCHED:
    case PTHREAD_EXPLICIT_SCHED:
      attr->inheritsched = inheritsched;
      return 0;

    default:
      return EINVAL;
  }
}

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Attributes, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_getinheritsched(
  const pthread_attr_t  *attr,
  int                   *inheritsched
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  *inheritsched = attr->inheritsched;
  return 0;
}

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Attributes, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_setschedpolicy(
  pthread_attr_t  *attr,
  int              policy
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  switch ( policy ) {
    case SCHED_OTHER:
    case SCHED_FIFO:
    case SCHED_RR:
    case SCHED_SPORADIC:
      attr->schedpolicy = policy;
      return 0;
 
    default:
      return EINVAL;
  }
}

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Parameters, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_getschedpolicy(
  const pthread_attr_t  *attr,
  int                   *policy
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  *policy = attr->schedpolicy;
  return 0;
}

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Parameters, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_setschedparam(
  pthread_attr_t           *attr,
  const struct sched_param *param
)
{
  if ( !attr || !attr->is_initialized || !param )
    return EINVAL;

  attr->schedparam = *param;
  return 0;
}

/*PAGE
 *
 *  13.5.1 Thread Creation Scheduling Attributes, P1003.1c/Draft 10, p. 120
 */

int pthread_attr_getschedparam(
  const pthread_attr_t   *attr,
  struct sched_param     *param
)
{
  if ( !attr || !attr->is_initialized || !param )
    return EINVAL;

  *param = attr->schedparam;
  return 0;
}

/*PAGE
 *
 *  13.5.2 Dynamic Thread Scheduling Parameters Access, 
 *         P1003.1c/Draft 10, p. 124
 */

int pthread_getschedparam(
  pthread_t           thread,
  int                *policy,
  struct sched_param *param
)
{
  Objects_Locations        location;
  POSIX_API_Control       *api;
  register Thread_Control *the_thread;

  if ( !policy || !param  )
    return EINVAL;

  the_thread = _POSIX_Threads_Get( thread, &location );
  switch ( location ) {
    case OBJECTS_ERROR:
    case OBJECTS_REMOTE:
      return ESRCH;
    case OBJECTS_LOCAL:
      api = the_thread->API_Extensions[ THREAD_API_POSIX ];
      *policy = api->schedpolicy;
      *param  = api->schedparam;
      param->sched_priority =
        _POSIX_Priority_From_core( the_thread->current_priority );
      _Thread_Enable_dispatch();
      return 0;
  }
 
  return POSIX_BOTTOM_REACHED();

}

/*PAGE
 *
 *  13.5.2 Dynamic Thread Scheduling Parameters Access, 
 *         P1003.1c/Draft 10, p. 124
 */

int pthread_setschedparam(
  pthread_t           thread,
  int                 policy,
  struct sched_param *param
)
{
  register Thread_Control             *the_thread;
  POSIX_API_Control                   *api;
  Thread_CPU_budget_algorithms         budget_algorithm;
  Thread_CPU_budget_algorithm_callout  budget_callout;
  Objects_Locations                    location;
 
  /*
   *  Check all the parameters
   */

  if ( !param )
    return EINVAL;

  if ( !_POSIX_Priority_Is_valid( param->sched_priority ) )
    return EINVAL;

  budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_NONE;
  budget_callout = NULL;

  switch ( policy ) {
    case SCHED_OTHER:
      budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE;
      break;
 
    case SCHED_FIFO:
      budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_NONE;
      break;
 
    case SCHED_RR:
      budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_EXHAUST_TIMESLICE;
      break;
 
    case SCHED_SPORADIC:
      budget_algorithm  = THREAD_CPU_BUDGET_ALGORITHM_CALLOUT;
      budget_callout = _POSIX_Threads_Sporadic_budget_callout;
 
      if ( _POSIX_Timespec_to_interval( &param->ss_replenish_period ) <
           _POSIX_Timespec_to_interval( &param->ss_initial_budget ) )
        return EINVAL;
 
      if ( !_POSIX_Priority_Is_valid( param->ss_low_priority ) )
        return EINVAL;
 
      break;
 
    default:
      return EINVAL;
  }

  /*
   *  Actually change the scheduling policy and parameters
   */

  the_thread = _POSIX_Threads_Get( thread, &location );
  switch ( location ) {
    case OBJECTS_ERROR:
    case OBJECTS_REMOTE:
      return ESRCH;
    case OBJECTS_LOCAL:
      api = the_thread->API_Extensions[ THREAD_API_POSIX ];

      if ( api->schedpolicy == SCHED_SPORADIC )
        (void) _Watchdog_Remove( &api->Sporadic_timer );

      api->schedpolicy = policy;
      api->schedparam  = *param;
      the_thread->budget_algorithm = budget_algorithm;
      the_thread->budget_callout   = budget_callout;

      switch ( api->schedpolicy ) {
        case SCHED_OTHER:
        case SCHED_FIFO:
        case SCHED_RR:
          the_thread->cpu_time_budget = _Thread_Ticks_per_timeslice;

          _Thread_Change_priority(
            the_thread, 
            _POSIX_Priority_To_core( api->schedparam.sched_priority )
          );
          break;
 
        case SCHED_SPORADIC:
          api->ss_high_priority = api->schedparam.sched_priority;
          _POSIX_Threads_Sporadic_budget_TSR( 0, the_thread );
          break;
      }

      _Thread_Enable_dispatch();
      return 0;
  }
  return POSIX_BOTTOM_REACHED();
}

/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_init(
  pthread_attr_t  *attr
)
{
  if ( !attr )
    return EINVAL;
 
  *attr = _POSIX_Threads_Default_attributes;
  return 0;
}

/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_destroy(
  pthread_attr_t  *attr
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;
 
  attr->is_initialized = FALSE;
  return 0;
}
 
/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_getstacksize(
  const pthread_attr_t  *attr,
  size_t                *stacksize
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  *stacksize = attr->stacksize;
  return 0;
}
 
/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_setstacksize(
  pthread_attr_t  *attr,
  size_t           stacksize
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  if (stacksize < STACK_MINIMUM_SIZE)
    attr->stacksize = STACK_MINIMUM_SIZE;
  else
    attr->stacksize = stacksize;
  return 0;
}
 
/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_getstackaddr(
  const pthread_attr_t   *attr,
  void                  **stackaddr
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  *stackaddr = attr->stackaddr;
  return 0;
}
 
/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_setstackaddr(
  pthread_attr_t  *attr,
  void            *stackaddr
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  attr->stackaddr = stackaddr;
  return 0;
}
 
/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_getdetachstate(
  const pthread_attr_t  *attr,
  int                   *detachstate
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  *detachstate = attr->detachstate;
  return 0;
}
 
/*PAGE
 *
 *  16.1.1 Thread Creation Attributes, P1003.1c/Draft 10, p, 140
 */

int pthread_attr_setdetachstate(
  pthread_attr_t  *attr,
  int              detachstate
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  switch ( detachstate ) {
    case PTHREAD_CREATE_DETACHED:
    case PTHREAD_CREATE_JOINABLE:
      attr->detachstate = detachstate;
      return 0;
 
    default:
      return EINVAL;
  }
}

/*PAGE
 *
 *  16.1.2 Thread Creation, P1003.1c/Draft 10, p. 144
 */

int pthread_create(
  pthread_t              *thread,
  const pthread_attr_t   *attr,
  void                 *(*start_routine)( void * ),
  void                   *arg
)
{
  const pthread_attr_t               *the_attr;
  Priority_Control                    core_priority;
  Thread_CPU_budget_algorithms        budget_algorithm;
  Thread_CPU_budget_algorithm_callout budget_callout;
  boolean                             is_fp;
  boolean                             status;
  Thread_Control                     *the_thread;
  char                               *default_name = "psx";
  POSIX_API_Control                  *api;
  int                                 schedpolicy = SCHED_RR;
  struct sched_param                  schedparam;

  the_attr = (attr) ? attr : &_POSIX_Threads_Default_attributes;

  if ( !the_attr->is_initialized )
    return EINVAL;

  /*
   *  Core Thread Initialize insures we get the minimum amount of
   *  stack space if it is allowed to allocate it itself.
   */

  if ( the_attr->stackaddr && !_Stack_Is_enough( the_attr->stacksize ) )
    return EINVAL;

#if 0
  int  cputime_clock_allowed;  /* see time.h */
  POSIX_NOT_IMPLEMENTED();
#endif

  /*
   *  P1003.1c/Draft 10, p. 121.
   *
   *  If inheritsched is set to PTHREAD_INHERIT_SCHED, then this thread
   *  inherits scheduling attributes from the creating thread.   If it is
   *  PTHREAD_EXPLICIT_SCHED, then scheduling parameters come from the 
   *  attributes structure.
   */

  switch ( the_attr->inheritsched ) {
    case PTHREAD_INHERIT_SCHED:
      api = _Thread_Executing->API_Extensions[ THREAD_API_POSIX ];
      schedpolicy = api->schedpolicy;
      schedparam  = api->schedparam;
      break; 

    case PTHREAD_EXPLICIT_SCHED:
      schedpolicy = the_attr->schedpolicy;
      schedparam  = the_attr->schedparam;
      break; 

    default:
      return EINVAL;
  }

  /*
   *  Check the contentionscope since rtems only supports PROCESS wide 
   *  contention (i.e. no system wide contention).
   */

  if ( the_attr->contentionscope != PTHREAD_SCOPE_PROCESS )
    return ENOSYS;

  /*
   *  Interpret the scheduling parameters.
   */

  if ( !_POSIX_Priority_Is_valid( schedparam.sched_priority ) )
    return EINVAL;
 
  core_priority = _POSIX_Priority_To_core( schedparam.sched_priority );
 
  /*
   *  Set the core scheduling policy information.
   */

  budget_callout = NULL;
  budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_NONE;

  switch ( schedpolicy ) {
    case SCHED_OTHER:
      budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE;
      break;
     
    case SCHED_FIFO:
      budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_NONE;
      break;

    case SCHED_RR:
      budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_EXHAUST_TIMESLICE;
      break;

    case SCHED_SPORADIC:
      budget_algorithm  = THREAD_CPU_BUDGET_ALGORITHM_CALLOUT;
      budget_callout = _POSIX_Threads_Sporadic_budget_callout;
  
      if ( _POSIX_Timespec_to_interval( &schedparam.ss_replenish_period ) <
           _POSIX_Timespec_to_interval( &schedparam.ss_initial_budget ) )
        return EINVAL;

      if ( !_POSIX_Priority_Is_valid( schedparam.ss_low_priority ) )
        return EINVAL;

      break;

    default:
      return EINVAL;
  }

  /*
   *  Currently all POSIX threads are floating point if the hardware 
   *  supports it.
   */

  is_fp = CPU_HARDWARE_FP;

  /*
   *  Disable dispatch for protection
   */
 
  _Thread_Disable_dispatch();
 
  /*
   *  Allocate the thread control block.
   *
   *  NOTE:  Global threads are not currently supported.
   */

  the_thread = _POSIX_Threads_Allocate();

  if ( !the_thread ) {
    _Thread_Enable_dispatch();
    return EINVAL;
  }

  /*
   *  Initialize the core thread for this task.
   */
 
  status = _Thread_Initialize(
    &_POSIX_Threads_Information,
    the_thread,
    the_attr->stackaddr,
    the_attr->stacksize,
    is_fp,
    core_priority,
    TRUE,                 /* preemptible */
    budget_algorithm,
    budget_callout,
    0,                    /* isr level */
    &default_name         /* posix threads don't have a name */
  );
 
  if ( !status ) {
    _POSIX_Threads_Free( the_thread );
    _Thread_Enable_dispatch();
    return EINVAL;
  }

  /*
   *  finish initializing the per API structure
   */

  
  api = the_thread->API_Extensions[ THREAD_API_POSIX ];

  api->Attributes  = *the_attr;
  api->detachstate = attr->detachstate;
  api->schedpolicy = schedpolicy;
  api->schedparam  = schedparam;

  /*
   *  This insures we evaluate the process-wide signals pending when we
   *  first run.
   *
   *  NOTE:  Since the thread starts with all unblocked, this is necessary.
   */

  the_thread->do_post_task_switch_extension = TRUE;

  /*
   *  POSIX threads are allocated and started in one operation.
   */

  status = _Thread_Start(
    the_thread,
    THREAD_START_POINTER,
    start_routine,
    arg,
    0                     /* unused */
  );

  if ( schedpolicy == SCHED_SPORADIC ) {
    _Watchdog_Insert_ticks(
      &api->Sporadic_timer,
      _POSIX_Timespec_to_interval( &api->schedparam.ss_replenish_period )
    );
  }

  /*
   *  _Thread_Start only fails if the thread was in the incorrect state
   */

  if ( !status ) {
    _POSIX_Threads_Free( the_thread );
    _Thread_Enable_dispatch();
    return EINVAL;
  }

  /*
   *  Return the id and indicate we successfully created the thread
   */

  *thread = the_thread->Object.id;

 _Thread_Enable_dispatch();

 return 0;
}

/*PAGE
 *
 *  16.1.3 Wait for Thread Termination, P1003.1c/Draft 10, p. 147
 */

int pthread_join(
  pthread_t   thread,
  void      **value_ptr
)
{
  register Thread_Control *the_thread;
  POSIX_API_Control       *api;
  Objects_Locations        location;
  void                    *return_pointer;

  the_thread = _POSIX_Threads_Get( thread, &location );
  switch ( location ) {
    case OBJECTS_ERROR:
    case OBJECTS_REMOTE:
      return ESRCH;
    case OBJECTS_LOCAL:
      api = the_thread->API_Extensions[ THREAD_API_POSIX ];

      if ( api->detachstate == PTHREAD_CREATE_DETACHED ) {
        _Thread_Enable_dispatch();
        return EINVAL;
      }

      if ( _Thread_Is_executing( the_thread ) ) {
        _Thread_Enable_dispatch();
        return EDEADLK;
      }

      /*
       *  Put ourself on the threads join list
       */

      _Thread_Executing->Wait.return_argument = (unsigned32 *) &return_pointer;

      _Thread_queue_Enter_critical_section( &api->Join_List );

      _Thread_queue_Enqueue( &api->Join_List, WATCHDOG_NO_TIMEOUT );

      _Thread_Enable_dispatch();

      if ( value_ptr )
        *value_ptr = return_pointer;
      return 0;
  }

  return POSIX_BOTTOM_REACHED();
}

/*PAGE
 *
 *  16.1.4 Detaching a Thread, P1003.1c/Draft 10, p. 149
 */

int pthread_detach(
  pthread_t   thread
)
{
  register Thread_Control *the_thread;
  POSIX_API_Control       *api;
  Objects_Locations        location;
 
  the_thread = _POSIX_Threads_Get( thread, &location );
  switch ( location ) {
    case OBJECTS_ERROR:
    case OBJECTS_REMOTE:
      return ESRCH;
    case OBJECTS_LOCAL:

      api = the_thread->API_Extensions[ THREAD_API_POSIX ];
      api->detachstate = PTHREAD_CREATE_DETACHED;
      _Thread_Enable_dispatch();
      return 0;
  }
 
  return POSIX_BOTTOM_REACHED();
}

/*PAGE
 *
 *  16.1.5.1 Thread Termination, p1003.1c/Draft 10, p. 150
 *
 *  NOTE: Key destructors are executed in the POSIX api delete extension.
 */
 
void pthread_exit(
  void  *value_ptr
)
{
  _Thread_Disable_dispatch();

  _Thread_Executing->Wait.return_argument = (unsigned32 *)value_ptr;

  _Thread_Close( &_POSIX_Threads_Information, _Thread_Executing );

  _POSIX_Threads_Free( _Thread_Executing );

  _Thread_Enable_dispatch();
}

/*PAGE
 *
 *  16.1.6 Get Calling Thread's ID, p1003.1c/Draft 10, p. 152
 */

pthread_t pthread_self( void )
{
  return _Thread_Executing->Object.id;
}

/*PAGE
 *
 *  16.1.7 Compare Thread IDs, p1003.1c/Draft 10, p. 153
 *
 *  NOTE:  POSIX does not define the behavior when either thread id is invalid. 
 */

int pthread_equal( 
  pthread_t  t1,
  pthread_t  t2
)
{
  /*
   *  If the system is configured for debug, then we will do everything we
   *  can to insure that both ids are valid.  Otherwise, we will do the
   *  cheapest possible thing to determine if they are equal.
   */

#ifndef RTEMS_DEBUG
  return _Objects_Are_ids_equal( t1, t2 );
#else
  int               status;
  Objects_Locations location;

  /*
   *  By default this is not a match.
   */

  status = 0;

  /*
   *  Validate the first id and return 0 if it is not valid
   */

  (void) _POSIX_Threads_Get( t1, &location );
  switch ( location ) {
    case OBJECTS_ERROR:
    case OBJECTS_REMOTE:
      break;

    case OBJECTS_LOCAL:

      /*
       *  Validate the second id and return 0 if it is not valid
       */

      (void) _POSIX_Threads_Get( t2, &location );
      switch ( location ) {
        case OBJECTS_ERROR:
        case OBJECTS_REMOTE:
          break; 
        case OBJECTS_LOCAL:
          status = _Objects_Are_ids_equal( t1, t2 ); 
          break;
      }
      _Thread_Unnest_dispatch();
      break;
  }

  _Thread_Enable_dispatch();
  return status;
#endif
}

/*PAGE
 *
 *  16.1.8 Dynamic Package Initialization, P1003.1c/Draft 10, p. 154
 */

int pthread_once(
  pthread_once_t  *once_control,
  void           (*init_routine)(void)
)
{
  if ( !once_control || !init_routine )
    return EINVAL;

  _Thread_Disable_dispatch();

  if ( !once_control->init_executed ) {
    once_control->is_initialized = TRUE;
    once_control->init_executed = TRUE;
    (*init_routine)();
  }
  
  _Thread_Enable_dispatch();
  return 0;
}

/*PAGE
 *
 *  20.1.6 Accessing a Thread CPU-time Clock, P1003.4b/Draft 8, p. 58
 */
 
int pthread_getcpuclockid(
  pthread_t    pid,
  clockid_t   *clock_id
)
{
  return POSIX_NOT_IMPLEMENTED();
}

/*PAGE
 *
 *  20.1.7 CPU-time Clock Thread Creation Attribute, P1003.4b/Draft 8, p. 59
 */

int pthread_attr_setcputime(
  pthread_attr_t  *attr,
  int              clock_allowed
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  switch ( clock_allowed ) {
    case CLOCK_ENABLED:
    case CLOCK_DISABLED:
      attr->cputime_clock_allowed = clock_allowed;
      return 0;
 
    default:
      return EINVAL;
  }
}

/*PAGE
 *
 *  20.1.7 CPU-time Clock Thread Creation Attribute, P1003.4b/Draft 8, p. 59
 */

int pthread_attr_getcputime(
  pthread_attr_t  *attr,
  int             *clock_allowed
)
{
  if ( !attr || !attr->is_initialized )
    return EINVAL;

  *clock_allowed = attr->cputime_clock_allowed;
  return 0;
}