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/*

 * Project: S.Ha.R.K.

 *

 * Coordinators:

 *   Giorgio Buttazzo    <giorgio@sssup.it>

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *

 * Authors     :

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *   (see the web pages for full authors list)

 *

 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)

 *

 * http://www.sssup.it

 * http://retis.sssup.it

 * http://shark.sssup.it

 */

/**

 ------------

 CVS :        $Id: grpcreat.c,v 1.7 2004-03-10 14:51:42 giacomo Exp $

 File:        $File$

 Revision:    $Revision: 1.7 $

 Last update: $Date: 2004-03-10 14:51:42 $

 ------------

 This file contains:

 - the function that creates a task

**/

/*

 * Copyright (C) 2000 Paolo Gai

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 */

#include <stdarg.h>

#include <ll/ll.h>

#include <ll/stdlib.h>

#include <ll/stdio.h>

#include <ll/string.h>

#include <kernel/config.h>

#include <kernel/model.h>

#include <kernel/const.h>

#include <sys/types.h>

#include <kernel/types.h>

#include <kernel/descr.h>

#include <errno.h>

#include <kernel/var.h>

#include <kernel/func.h>

//#include <kernel/trace.h>

#include <tracer.h>

static DWORD unique_task_ID = 0;

/*+ Task create stub:

    when a task is created, the context is initialized to call this stub.

    Why??? for 2 reasons:

    - The signal delivery is done in the kern_context_load. When a task is

      created and activated but before the first dispatch, some signals

      could arrive... so the first thing a task have to do is to deliver

      pending signals...

    - When a task ends, it can return a value, so the value can be easily

      managed in the stub to implement task_join & co...

+*/

static void task_create_stub(void *arg)

{

  void *ret;

  kern_after_dispatch();

  ret = proc_table[exec_shadow].body(arg);

  kern_cli();

  //  kern_printf("EXIT task %d, value %d\n",exec_shadow,ret); 

  task_makefree(ret);

  // kern_printf("MAKEFREE return exec_shadow=%d task_counter=%d\n",exec_shadow,task_counter); 

  ll_context_to(proc_table[exec_shadow].context);

}

/*+

  Allocate & fill a task descriptor;

  After that call the task is ready to be guaranteed.

  look at group_create for some other comments :-)

  +*/

static

PID internal_create_init(char *name, /*+ the symbolic name of the task +*/

                         TASK (*body)(), /*+ a pointer to the task body    +*/

                         TASK_MODEL *m,  /*+ the task model                +*/

                         va_list rlist)  /*+ used to manage the resources

                                           models +*/

{

  PID i = NIL;     /* the task descriptor to fill... */

  LEVEL l;         /* used for searching the correct level of the task    */

  RLEVEL l_res;    /* used for searching the correct resource level ...   */

  RES_MODEL *r;    /* used for managing the resources models */

  int j;           /* a counter */

  /* Get a free descriptor */

  for (;;) {

    i = iq_getfirst(&freedesc);

    /* If no one is available abort the system */

    if (i == NIL) {

      errno = ENO_AVAIL_TASK;

      return -1;

    }

    if (!(proc_table[i].control & WAIT_FOR_JOIN))

      break;

    proc_table[i].control |= DESCRIPTOR_DISCARDED;

  }

  /* Fill in the descriptor */

  proc_table[i].task_ID         = unique_task_ID++;

  proc_table[i].body            = body;

  strncpy(proc_table[i].name,name,19);

  proc_table[i].name[19]        = 0;

  proc_table[i].status          = SLEEP;    /* Task is not active when created */

  proc_table[i].pclass          = m->pclass & 0xFF00;

  proc_table[i].group           = m->group;

  proc_table[i].stacksize       = (m->stacksize == 0) ? STACK_SIZE : m->stacksize;

  proc_table[i].control         = m->control | KILL_DEFERRED | KILL_ENABLED;

  proc_table[i].frozen_activations = 0;

  proc_table[i].sigmask         = proc_table[exec_shadow].sigmask; /* mask inherit.*/

  proc_table[i].sigpending      = 0; /* No pending signal for new tasks*/

  proc_table[i].shadow          = i;

  proc_table[i].cleanup_stack   = NULL;

  //  proc_table[i].next            = proc_table[i].prev = NIL;

  proc_table[i].errnumber       = 0;        /* meaningless value */

  /* Fill jet info */

  proc_table[i].jet_tvalid      = 0;

  proc_table[i].jet_curr        = 0;

  proc_table[i].jet_max         = 0;

  proc_table[i].jet_sum         = 0;

  proc_table[i].jet_n           = 0;

  for (j=0; j<JET_TABLE_DIM; j++)

     proc_table[i].jet_table[j] = 0;

  proc_table[i].waiting_for_me  = NIL;

  proc_table[i].return_value    = NULL;

  proc_table[i].keys[0] = &proc_table[i].cleanup_stack;

  for (j=1; j<PTHREAD_KEYS_MAX; j++)

    proc_table[i].keys[j] = NULL;

  /* now, the task descriptor has some fields not initializated:

     - master_level   (initialized later, modified by l[]->task_create() )

     - task_level     (initialized later in this function)

     - context, stack (initialized at the end of this function)

     - additional stuff like priority & co. have to be init. only if used...)

     - delay_timer    (initialized in __kernel_init__ and mantained coherent

                       by the scheduling modules...)

     - guest_pclass   (set only in guest_create and used with guest task)

  */

  /* search for a level that can manage the task model */

  for (l=level_first; l != -1; l=level_next[l])

    if (level_table[l]->public_create(l,i,m) >= 0)

      break;

  if (l == -1) {

    /* no level can accept the task_model, exit!!! */

    proc_table[i].status = FREE;

    iq_insertfirst(i,&freedesc);

    errno = ENO_AVAIL_SCHEDLEVEL;

    return -1;

  }

  /* initialize task level */

  proc_table[i].task_level = l;

  /* register all the resource models passed */

  for (;;) {

    r = va_arg(rlist,RES_MODEL *);

    if (!r) break;   /* all the resource models are managed */

    /* search for a level that can manage the resource model */

    for (l_res=0; l_res<res_levels; l_res++)

      if (resource_table[l_res]->res_register(l_res, i, r) >= 0)

        break;

    if (l_res == res_levels) {

      /* no level can accept the resource_model, exit!!! */

      /* detach the resources and the task */

      group_create_reject(i);

      errno = ENO_AVAIL_RESLEVEL;

      return -1;

    }

  }

  return i;

}

/* This function allow to create a set of tasks without guarantee.

   It must be called with interrupts disabled and it must be used with

   group_create_accept and group_create_reject.

   This function allocates a task descriptor and fills it.

   After that, the guarantee() function should be called to check for task(s)

   admission.

   Next, each task created with group_create must be accepted with a call to

   group_create_accept() or rejected with a call to group_create_reject.

   The function returns the PID of the allocated descriptor, or NIL(-1)

   if the descriptor cannot be allocated or some problems arises the creation.

   If -1 is returned, errno is set to a value that represent the error:

      ENO_AVAIL_TASK       -> no free descriptors available

      ENO_AVAIL_SCHEDLEVEL -> there were no scheduling modules that can handle

                              the TASK_MODEL *m passed as parameter

      ETASK_CREATE         -> there was an error during the creation of the

                              task into the scheduling module

      ENO_AVAIL_RESLEVEL   -> there were no resource modules that can handle

                              one of the RES_MODEL * passed as parameter

*/

PID group_create(char *name,

                 TASK (*body)(),

                 TASK_MODEL *m,

                 ...)

{

  PID p;

  va_list rlist;

  va_start(rlist, m);

  p = internal_create_init(name, body, m, rlist);

  va_end(rlist);

  return p;

}

/*

  This function should be called when a task created with group_create

  is successfully guaranteed and accepted in the system.

  This function finish the creation process allocating the last resources

  for the task (i.e., the stack and the context).

  it returns:

  -1 if something goes wrong. In this case, THE TASK IS AUTOMATICALLY REJECTED

     AND THE GROUP_CREATE_REJECT MUST NOT BE CALLED.

     errno is set to a value that explains the problem occurred:

     ENO_AVAIL_STACK_MEM -> No stack memory available for the task

     ENO_AVAIL_TSS       -> No context available for the task (This is a

                            CRITICAL error, and usually never happens...)

*/

int group_create_accept(PID i, TASK_MODEL *m)

{

  CONTEXT c;       /* the context of the new task */

  BYTE *tos;       /* top of stack of the new task */

  /* Allocate a stack for the task, only if stackaddr != NULL */

  if (m->stackaddr) {

    tos = proc_table[i].stack = m->stackaddr;

    proc_table[i].control |= STACKADDR_SPECIFIED;

  }

  else {

    tos = proc_table[i].stack = (BYTE *) kern_alloc(proc_table[i].stacksize);

    if (proc_table[i].stack == NULL) {

      group_create_reject(i);

      errno = ENO_AVAIL_STACK_MEM;

      return -1;

    }

  }

  /* Set up the initial context */

  tos += proc_table[i].stacksize;

  c = kern_context_create(task_create_stub,tos,m->arg,NULL,m->control);

  // { extern CONTEXT global_context; 

  if (!c) { // || c == global_context) {

    /*    grx_close();

    { int i;

    for (i = 0; i<10000; i++)

    kern_printf("!!!\n"); ll_abort(666);*/

    kern_free(tos, proc_table[i].stacksize);

    group_create_reject(i);

    errno = ENO_AVAIL_TSS;

    return -1;

  }

/*

  printf_xy(0,0,WHITE,"context = %d global=%d stack=%p",c,global_context,proc_table[i].stack);

  }*/

  proc_table[i].context = c;

  /* Tracer stuff */

  TRACER_LOGEVENT(FTrace_EVT_task_create,(unsigned short int)c,(unsigned int)i);

  //kern_printf("[c%i %i]",i,proc_table[i].context);

  /* Count the task if it is an Application or System Task... */

  if (!(m->control & SYSTEM_TASK))

    task_counter++;

  else if (!(m->control & NO_KILL))

    system_counter++;

  return 0;

}

/*

  This function should be called when a task created with group_create

  can not be successfully guaranteed.

  This function reject the task from the system.

  You cannot use the PID of a rejected task after this call.

*/

void group_create_reject(PID i)

{

  LEVEL  l;     /* stores the level of a task */

  RLEVEL lr;    /* used for searching the correct resource level ...   */

  for (lr=0; lr<res_levels; lr++)

    resource_table[lr]->res_detach(lr,i);

  l = proc_table[i].task_level;  

  level_table[l]->public_detach(l,i);

  proc_table[i].status = FREE;

  iq_insertfirst(i,&freedesc);

}

/*+

  Allocate & fill a task descriptor; the task is not explicitely

  activated; you have to use the task_activate to do this

  Just set up the minimum necessary to make thing works well          

  This function creates and guarantees a task using the group_create

  functions.

  If in your code you never need to create group of tasks, consider replacing

  this file with the file kernel/create.c, that handle all the task

  creation process in a single function call.

+*/

PID task_createn(char *name,      /*+ the symbolic name of the task +*/

                 TASK (*body)(),  /*+ a pointer to the task body    +*/

                 TASK_MODEL *m,   /*+ the task model                +*/

                 ...)             /*+ the resources models, a list

                                     of RES_MODEL * terminated by NULL +*/

{

  PID p;           /* the task descriptor to fill... */

  va_list rlist;   /* used for managing the resources models */

  SYS_FLAGS f;     /* the flags to be restored at the end

                      (we must save them because the task_create can be

                       called at system initialization) */

  f = kern_fsave();

  va_start(rlist, m);

  p = internal_create_init(name, body, m, rlist);

  va_end(rlist);

  if (p != NIL) {

    if (level_table[proc_table[p].task_level]->public_guarantee)

      if (guarantee() < 0) {

        group_create_reject(p);

        errno = ENO_GUARANTEE;

        kern_frestore(f);

        return -1;

      }

    if (group_create_accept(p,m)) p = -1;

  }

  kern_frestore(f);

  return p;

}