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/*

 *  kill() support routine

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: killinfo.c,v 1.2 2001-09-27 11:59:17 chris Exp $

 */

#include <pthread.h>

#include <signal.h>

#include <errno.h>

#include <assert.h>

#include <rtems/system.h>

#include <rtems/posix/pthread.h>

#include <rtems/posix/psignal.h>

#include <rtems/posix/seterr.h>

#include <rtems/score/isr.h>

/*PAGE

 *

 *  3.3.2 Send a Signal to a Process, P1003.1b-1993, p. 68

 *

 *  NOTE: Behavior of kill() depends on _POSIX_SAVED_IDS.

 */

#define _POSIX_signals_Is_interested( _api, _mask ) \

  ( ~(_api)->signals_blocked & (_mask) )

int killinfo(

  pid_t               pid,

  int                 sig,

  const union sigval *value

)

{

  sigset_t                     mask;

  POSIX_API_Control           *api;

  unsigned32                   the_class;

  unsigned32                   index;

  unsigned32                   maximum;

  Objects_Information         *the_info;

  Objects_Control            **object_table;

  Thread_Control              *the_thread;

  Thread_Control              *interested_thread;

  Priority_Control             interested_priority;

  Chain_Control               *the_chain;

  Chain_Node                  *the_node;

  siginfo_t                    siginfo_struct;

  siginfo_t                   *siginfo;

  POSIX_signals_Siginfo_node  *psiginfo;

  /*

   *  Only supported for the "calling process" (i.e. this node).

   */

  if ( pid != getpid() )

    set_errno_and_return_minus_one( ESRCH );

  /*

   *  Validate the signal passed if not 0.

   */

  if ( sig && !is_valid_signo(sig) ) {

    set_errno_and_return_minus_one( EINVAL );

  }

  /*

   *  If the signal is being ignored, then we are out of here.

   */

  if ( !sig || _POSIX_signals_Vectors[ sig ].sa_handler == SIG_IGN ) {

    return 0;

  }

  /*

   *  P1003.1c/Draft 10, p. 33 says that certain signals should always

   *  be directed to the executing thread such as those caused by hardware

   *  faults.

   */

  switch ( sig ) {

    case SIGFPE:

    case SIGILL:

    case SIGSEGV:

      return pthread_kill( pthread_self(), sig );

    default:

      break;

  }

  mask = signo_to_mask( sig );

  /*

   *  Build up a siginfo structure

   */

  siginfo = &siginfo_struct;

  siginfo->si_signo = sig;

  siginfo->si_code = SI_USER;

  if ( !value ) {

    siginfo->si_value.sival_int = 0;

  } else {

    siginfo->si_value = *value;

  }

  _Thread_Disable_dispatch();

  /*

   *  Is the currently executing thread interested?  If so then it will

   *  get it an execute it as soon as the dispatcher executes.

   */

  the_thread = _Thread_Executing;

  api = the_thread->API_Extensions[ THREAD_API_POSIX ];

  if ( _POSIX_signals_Is_interested( api, mask ) ) {

    goto process_it;

  }

  /*

   *  Is an interested thread waiting for this signal (sigwait())?

   */

  /* XXX violation of visibility -- need to define thread queue support */

  for( index=0 ;

       index < TASK_QUEUE_DATA_NUMBER_OF_PRIORITY_HEADERS ;

       index++ ) {

    the_chain = &_POSIX_signals_Wait_queue.Queues.Priority[ index ];

    for ( the_node = the_chain->first ;

          !_Chain_Is_tail( the_chain, the_node ) ;

          the_node = the_node->next ) {

      the_thread = (Thread_Control *)the_node;

      api = the_thread->API_Extensions[ THREAD_API_POSIX ];

      if ((the_thread->Wait.option & mask) || (~api->signals_blocked & mask)) {

        goto process_it;

      }

    }

  }

  /*

   *  Is any other thread interested?  The highest priority interested

   *  thread is selected.  In the event of a tie, then the following

   *  additional criteria is used:

   *

   *    + ready thread over blocked

   *    + blocked on call interruptible by signal (can return EINTR)

   *    + blocked on call not interruptible by signal

   *

   *  This looks at every thread in the system regardless of the creating API.

   *

   *  NOTES:

   *

   *    + rtems internal threads do not receive signals.

   */

  interested_thread = NULL;

  interested_priority = PRIORITY_MAXIMUM + 1;

  for ( the_class = OBJECTS_CLASSES_FIRST_THREAD_CLASS;

        the_class <= OBJECTS_CLASSES_LAST_THREAD_CLASS;

        the_class++ ) {

    if ( the_class == OBJECTS_INTERNAL_THREADS )

      continue;

    the_info = _Objects_Information_table[ the_class ];

    if ( !the_info )                        /* manager not installed */

      continue;

    maximum = the_info->maximum;

    object_table = the_info->local_table;

    assert( object_table );                 /* always at least 1 entry */

    for ( index = 1 ; index <= maximum ; index++ ) {

      the_thread = (Thread_Control *) object_table[ index ];

      if ( !the_thread )

        continue;

      /*

       *  If this thread is of lower priority than the interested thread,

       *  go on to the next thread.

       */

      if ( the_thread->current_priority > interested_priority )

        continue;

      /*

       *  If this thread is not interested, then go on to the next thread.

       */

      api = the_thread->API_Extensions[ THREAD_API_POSIX ];

      if ( !api || !_POSIX_signals_Is_interested( api, mask ) )

        continue;

      /*

       *  Now we know the thread under connsideration is interested.

       *  If the thread under consideration is of higher priority, then

       *  it becomes the interested thread.

       */

      if ( the_thread->current_priority < interested_priority ) {

        interested_thread   = the_thread;

        interested_priority = the_thread->current_priority;

        continue;

      }

      /*

       *  Now the thread and the interested thread have the same priority.

       *  If the interested thread is ready, then we don't need to send it

       *  to a blocked thread.

       */

      if ( _States_Is_ready( interested_thread->current_state ) )

        continue;

      /*

       *  Now the interested thread is blocked.

       *  If the thread we are considering is not, the it becomes the

       *  interested thread.

       */

      if ( _States_Is_ready( the_thread->current_state ) ) {

        interested_thread   = the_thread;

        interested_priority = the_thread->current_priority;

        continue;

      }

      /*

       *  Now we know both threads are blocked.

       *  If the interested thread is interruptible, then just use it.

       */

      /* XXX need a new states macro */

      if ( interested_thread->current_state & STATES_INTERRUPTIBLE_BY_SIGNAL )

        continue;

      /*

       *  Now both threads are blocked and the interested thread is not

       *  interruptible.

       *  If the thread under consideration is interruptible by a signal,

       *  then it becomes the interested thread.

       */

      /* XXX need a new states macro */

      if ( the_thread->current_state & STATES_INTERRUPTIBLE_BY_SIGNAL ) {

        interested_thread   = the_thread;

        interested_priority = the_thread->current_priority;

      }

    }

  }

  if ( interested_thread ) {

    the_thread = interested_thread;

    goto process_it;

  }

  /*

   *  OK so no threads were interested right now.  It will be left on the

   *  global pending until a thread receives it.  The global set of threads

   *  can change interest in this signal in one of the following ways:

   *

   *    + a thread is created with the signal unblocked,

   *    + pthread_sigmask() unblocks the signal,

   *    + sigprocmask() unblocks the signal, OR

   *    + sigaction() which changes the handler to SIG_IGN.

   */

  the_thread = NULL;

  goto post_process_signal;

  /*

   *  We found a thread which was interested, so now we mark that this

   *  thread needs to do the post context switch extension so it can

   *  evaluate the signals pending.

   */

process_it:

  the_thread->do_post_task_switch_extension = TRUE;

  /*

   *  Returns TRUE if the signal was synchronously given to a thread

   *  blocked waiting for the signal.

   */

  if ( _POSIX_signals_Unblock_thread( the_thread, sig, siginfo ) ) {

    _Thread_Enable_dispatch();

    return 0;

  }

post_process_signal:

  /*

   *  We may have woken up a thread but we definitely need to post the

   *  signal to the process wide information set.

   */

  _POSIX_signals_Set_process_signals( mask );

  if ( _POSIX_signals_Vectors[ sig ].sa_flags == SA_SIGINFO ) {

    psiginfo = (POSIX_signals_Siginfo_node *)

               _Chain_Get( &_POSIX_signals_Inactive_siginfo );

    if ( !psiginfo ) {

      set_errno_and_return_minus_one( EAGAIN );

    }

    psiginfo->Info = *siginfo;

    _Chain_Append( &_POSIX_signals_Siginfo[ sig ], &psiginfo->Node );

  }

  _Thread_Enable_dispatch();

  return 0;

}