source: rtems/cpukit/libcsupport/src/newlibc.c @ 5b9d6ddf

/*
 *      @(#)newlibc.c   1.9 - 95/05/16
 *      
 */

#if defined(RTEMS_NEWLIB)

/*
 *  File:       newlibc.c,v
 *  Project:    PixelFlow
 *  Created:    94/12/7
 *  Revision:   1.2
 *  Last Mod:   1995/05/09 20:24:37
 *
 *  COPYRIGHT (c) 1994 by Division Incorporated
 *
 *  To anyone who acknowledges that this file is provided "AS IS"
 *  without any express or implied warranty:
 *      permission to use, copy, modify, and distribute this file
 *      for any purpose is hereby granted without fee, provided that
 *      the above copyright notice and this notice appears in all
 *      copies, and that the name of Division Incorporated not be
 *      used in advertising or publicity pertaining to distribution
 *      of the software without specific, written prior permission.
 *      Division Incorporated makes no representations about the
 *      suitability of this software for any purpose.
 *
 *  Description:
 *      Implementation of hooks for the CYGNUS newlib libc
 *      These hooks set things up so that:
 *              '_REENT' is switched at task switch time.
 *
 *
 *  TODO:
 *
 *  NOTE:
 *
 *  newlibc.c,v 1.2 1995/05/09 20:24:37 joel Exp
 *
 */

#include <rtems.h>
#include <libcsupport.h>
#include <stdlib.h>             /* for free() */
#include <string.h>             /* for memset() */

#include <sys/reent.h>          /* for extern of _REENT (aka _impure_ptr) */

#include "internal.h"

#define LIBC_NOTEPAD RTEMS_NOTEPAD_LAST


int              libc_reentrant;        /* do we think we are reentrant? */
struct _reent    libc_global_reent = _REENT_INIT(libc_global_reent);;

/*
 * CYGNUS newlib routine that does atexit() processing and flushes
 *      stdio streams
 *      undocumented
 */

extern void _wrapup_reent(struct _reent *);
extern void _reclaim_reent(struct _reent *);

void
libc_wrapup(void)
{
    _wrapup_reent(0);
    if (_REENT != &libc_global_reent)
    {
        _wrapup_reent(&libc_global_reent);
#if 0
        /* don't reclaim this one, just in case we do printfs */
        /* on our way out to ROM */
        _reclaim_reent(&libc_global_reent);
#endif
        _REENT = &libc_global_reent;
    }
}


rtems_extension
libc_create_hook(rtems_tcb *current_task,
                 rtems_tcb *creating_task)
{
    MY_task_set_note(creating_task, LIBC_NOTEPAD, 0);
}

/*
 * Called for all user TASKS (system tasks are SYSI and IDLE)
 */

rtems_extension
libc_start_hook(rtems_tcb *current_task,
                rtems_tcb *starting_task)
{
    struct _reent *ptr;

    /* NOTE: our malloc is reentrant without a reent ptr since
     *  it is based on region manager
     */

    ptr = (struct _reent *) malloc(sizeof(struct _reent));

    /* GCC extension: structure constants */
    *ptr = (struct _reent) _REENT_INIT((*ptr));

    MY_task_set_note(starting_task, LIBC_NOTEPAD, (rtems_unsigned32) ptr);
}

rtems_extension
libc_switch_hook(rtems_tcb *current_task,
                 rtems_tcb *heir_task)
{
    rtems_unsigned32 impure_value;

    /* XXX We can't use rtems_task_set_note() here since SYSI task has a
     * tid of 0, which is treated specially (optimized, actually)
     * by rtems_task_set_note
     */

    impure_value = (rtems_unsigned32) _REENT;
    MY_task_set_note(current_task, LIBC_NOTEPAD, impure_value);

    _REENT = (struct _reent *) MY_task_get_note(heir_task, LIBC_NOTEPAD);

}

/*
 *  Function:   libc_delete_hook
 *  Created:    94/12/10
 *
 *  Description:
 *      Called when a task is deleted.
 *      Must restore the new lib reentrancy state for the new current
 *      task.
 *
 *  Parameters:
 *
 *
 *  Returns:
 *
 *
 *  Side Effects:
 *
 *  Notes:
 *
 *
 *  Deficiencies/ToDo:
 *
 *
 */
rtems_extension
libc_delete_hook(rtems_tcb *current_task,
                 rtems_tcb *deleted_task)
{
    struct _reent *ptr;

    /*
     * The reentrancy structure was allocated by newlib using malloc()
     */

    if (current_task == deleted_task)
    {
        ptr = _REENT;
    }
    else
    {
        ptr = (struct _reent *) MY_task_get_note(deleted_task, LIBC_NOTEPAD);
    }

    if (ptr)
    {
        _wrapup_reent(ptr);
        _reclaim_reent(ptr);
    }

    MY_task_set_note(deleted_task, LIBC_NOTEPAD, 0);

    /*
     * Require the switch back to another task to install its own
     */

    if (current_task == deleted_task)
    {
        _REENT = 0;
    }
}

/*
 *  Function:   libc_init
 *  Created:    94/12/10
 *
 *  Description:
 *      Init libc for CYGNUS newlib
 *      Set up _REENT to use our global libc_global_reent.
 *      (newlib provides a global of its own, but we prefer our
 *      own name for it)
 *
 *      If reentrancy is desired (which it should be), then
 *      we install the task extension hooks to maintain the
 *      newlib reentrancy global variable _REENT on task
 *      create, delete, switch, exit, etc.
 *
 *  Parameters:
 *      reentrant               non-zero if reentrant library desired.
 *
 *  Returns:
 *
 *  Side Effects:
 *      installs libc extensions if reentrant.
 *
 *  Notes:
 *
 *
 *  Deficiencies/ToDo:
 *
 */

void
libc_init(int reentrant)
{
    rtems_extensions_table  libc_extension;
    rtems_id                extension_id;
    rtems_status_code       rc;

    _REENT = &libc_global_reent;

    if (reentrant)
    {
        memset(&libc_extension, 0, sizeof(libc_extension));

        libc_extension.rtems_task_create  = libc_create_hook;
        libc_extension.rtems_task_start   = libc_start_hook;
        libc_extension.task_switch  = libc_switch_hook;
        libc_extension.rtems_task_delete  = libc_delete_hook;

        rc = rtems_extension_create(rtems_build_name('L', 'I', 'B', 'C'),
                              &libc_extension, &extension_id);
        if (rc != RTEMS_SUCCESSFUL)
            rtems_fatal_error_occurred(rc);

        libc_reentrant = reentrant;
    }
}


void
exit(int status)
{
    libc_wrapup();
    rtems_shutdown_executive(status);
}


/*
 *  Function:   _exit
 *  Created:    94/12/10
 *
 *  Description:
 *      Called from exit() after it does atexit() processing and stdio fflush's
 *
 *      called from bottom of exit() to really delete the task.
 *      If we are using reentrant libc, then let the delete extension
 *      do all the work, otherwise if a shutdown is in progress,
 *      then just do it.
 *
 *  Parameters:
 *      exit status
 *
 *  Returns:
 *      does not return
 *
 *  Side Effects:
 *
 *  Notes:
 *
 *
 *  Deficiencies/ToDo:
 *
 *
 */

#ifndef RTEMS_UNIX
void _exit(int status)
{
    rtems_shutdown_executive(status);
}
#endif

#endif