rom/exec/remtask.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Remove a task
   6     Lang: english
   7 */
   8
   9 #include <aros/debug.h>
  10 #include <exec/execbase.h>
  11 #include <exec/tasks.h>
  12 #include <aros/libcall.h>
  13 #include <proto/exec.h>
  14 #include <proto/kernel.h>
  15 #include <aros/symbolsets.h>
  16
  17 #include "exec_intern.h"
  18 #include "exec_util.h"
  19 #include "exec_debug.h"
  20
  21 /*****************************************************************************
  22
  23     NAME */
  24
  25         AROS_LH1(void, RemTask,
  26
  27 /*  SYNOPSIS */
  28         AROS_LHA(struct Task *, task, A1),
  29
  30 /*  LOCATION */
  31         struct ExecBase *, SysBase, 48, Exec)
  32
  33 /*  FUNCTION
  34         Remove a task from the task lists. All memory in the tc_MemEntry list
  35         is freed and a rescedule is done. It's safe to call RemTask() out
  36         of Forbid() or Disable().
  37         This function is one way to get rid of the current task. The other way
  38         is to fall through the end of the entry point.
  39
  40     INPUTS
  41         task - Task to be removed. NULL means current task.
  42
  43     RESULT
  44
  45     NOTES
  46
  47     EXAMPLE
  48
  49     BUGS
  50
  51     SEE ALSO
  52         AddTask()
  53
  54     INTERNALS
  55
  56     HISTORY
  57
  58 ******************************************************************************/
  59 {
  60     AROS_LIBFUNC_INIT
  61     struct ETask *et;
  62     BOOL suicide;
  63
  64     /* A value of NULL means current task */
  65     if (task==NULL)
  66         task=SysBase->ThisTask;
  67
  68     DREMTASK("RemTask (0x%p (\"%s\"))", task, task->tc_Node.ln_Name);
  69
  70     /* Don't let any other task interfere with us at the moment
  71     */
  72     Forbid();
  73
  74     suicide = (task == SysBase->ThisTask);
  75     if (suicide)
  76         DREMTASK("Removing itself");
  77
  78     /* Remove() here, before freeing the MemEntry list. Because
  79        the MemEntry list might contain the task struct itself! */
  80
  81     if (!suicide)
  82         Remove(&task->tc_Node);
  83
  84     /*
  85      * The task is being removed.
  86      * This is an important signal for Alert() which will not attempt to use
  87      * the context which is being deleted, for example.
  88      */
  89     task->tc_State = TS_REMOVED;
  90
  91     /* Delete context */
  92     et = GetETask(task);
  93     if (et != NULL)
  94         KrnDeleteContext(et->et_RegFrame);
  95
  96     /* Uninitialize ETask structure */
  97     DREMTASK("Cleaning up ETask et=%p", et);
  98     CleanupETask(task);
  99
 100     /*
 101      * Send task to task cleaner to clean up memory.
 102      * This avoids ripping memory from underneath a running Task.
 103      * Message is basically a Node, so we use our task's tc_Node as a message.
 104      * We use InternalPutMsg() because it won't change ln_Type. Just in case...
 105      */
 106     DREMTASK("Sending to garbage man");
 107     InternalPutMsg(((struct IntExecBase *)SysBase)->ServicePort, (struct Message *)task, SysBase);
 108
 109     /* Freeing myself? */
 110     if (suicide)
 111     {
 112         /* Changing the task lists always needs a Disable(). */
 113         Disable();
 114
 115         /*
 116             Since I don't know how many levels of Forbid()
 117             are already pending I set a default value.
 118         */
 119         SysBase->TDNestCnt = -1;
 120
 121         /* And force a task switch. Note: Dispatch, not Switch,
 122            because the state of ThisTask must not be saved
 123         */
 124
 125         KrnDispatch();
 126         /* Does not return. */
 127     }
 128
 129     /* All done. */
 130     Permit();
 131
 132     DREMTASK("Success");
 133
 134     AROS_LIBFUNC_EXIT
 135 }