rom/exec/childstatus.c

   1 /*
   2     Copyright © 1995-2017, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Find out the status of a child task.
   6 */
   7 #include "exec_intern.h"
   8 #include <proto/exec.h>
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13
  14         AROS_LH1(ULONG, ChildStatus,
  15
  16 /*  SYNOPSIS */
  17         AROS_LHA(ULONG, tid, D0),
  18
  19 /*  LOCATION */
  20         struct ExecBase *, SysBase, 125, Exec)
  21
  22 /*  FUNCTION
  23         Return the status of a child task. This allows the Task to
  24         determine whether a particular child task is still running or not.
  25
  26     INPUTS
  27         tid     --  The ID of the task to examine. Note that it is _NOT_
  28                     a task pointer.
  29
  30     RESULT
  31         One of the CHILD_* values.
  32
  33     NOTES
  34         This function will work correctly only for child tasks that are
  35         processes created with NP_NotifyOnDeath set to TRUE. Otherwise
  36         it may report CHILD_NOTFOUND even if child already exited.
  37
  38     EXAMPLE
  39
  40     BUGS
  41
  42     SEE ALSO
  43
  44     INTERNALS
  45
  46 *****************************************************************************/
  47 {
  48     AROS_LIBFUNC_INIT
  49
  50     struct Task     *ThisTask = GET_THIS_TASK;
  51     struct ETask    *et;
  52     struct ETask    *child;
  53     ULONG            status = CHILD_NOTFOUND;
  54
  55     if (ThisTask)
  56     {
  57         if ((ThisTask->tc_Flags & TF_ETASK) == 0)
  58         return CHILD_NOTNEW;
  59
  60         et = ThisTask->tc_UnionETask.tc_ETask;
  61
  62         /* Sigh... */
  63         Forbid();
  64
  65         /* Search through the running tasks list */
  66         ForeachNode(&et->et_Children, child)
  67         {
  68         if (child->et_UniqueID == tid)
  69         {
  70             status = CHILD_ACTIVE;
  71             break;
  72         }
  73         }
  74
  75 #if defined(__AROSEXEC_SMP__)
  76         EXEC_SPINLOCK_LOCK(&et->et_TaskMsgPort.mp_SpinLock, NULL, SPINLOCK_MODE_READ);
  77 #endif
  78         ForeachNode(&et->et_TaskMsgPort.mp_MsgList, child)
  79         {
  80         if (child->et_UniqueID == tid)
  81         {
  82             status = CHILD_EXITED;
  83             break;
  84         }
  85         }
  86 #if defined(__AROSEXEC_SMP__)
  87         EXEC_SPINLOCK_UNLOCK(&et->et_TaskMsgPort.mp_SpinLock);
  88 #endif
  89         Permit();
  90     }
  91     return status;
  92
  93     AROS_LIBFUNC_EXIT
  94 } /* ChildStatus */