stdio.c

/*
 * File     : stdio.c
 * Brief    : stdio for newlib
 *
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006 - 2017, RT-Thread Development Team
 *
 *  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.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2017/10/15     bernard      the first version
 */
#include <stdio.h>
#include <stdlib.h>

#include <rtthread.h>
#include "libc.h"

#define STDIO_DEVICE_NAME_MAX   32

static FILE* std_console = NULL;

int libc_stdio_set_console(const char* device_name, int mode)
{
    FILE *fp;
    char name[STDIO_DEVICE_NAME_MAX];
    char *file_mode;

    snprintf(name, sizeof(name) - 1, "/dev/%s", device_name);
    name[STDIO_DEVICE_NAME_MAX - 1] = '\0';

    if (mode == O_RDWR) file_mode = "r+";
    else if (mode == O_WRONLY) file_mode = "wb";
    else if (mode == O_RDONLY) file_mode = "rb";

    fp = fopen(name, file_mode);
    if (fp)
    {
        setvbuf(fp, NULL, _IONBF, 0);

        if (std_console)
        {
            fclose(std_console);
            std_console = NULL;
        }
        std_console = fp;

        if (mode == O_RDWR)
        {
            _GLOBAL_REENT->_stdin  = std_console;
        }
        else 
        {
            _GLOBAL_REENT->_stdin  = NULL;
        }

        if (mode == O_RDONLY)
        {
            _GLOBAL_REENT->_stdout = NULL;
            _GLOBAL_REENT->_stderr = NULL;
        }
        else
        {
            _GLOBAL_REENT->_stdout = std_console;
            _GLOBAL_REENT->_stderr = std_console;
        }

        _GLOBAL_REENT->__sdidinit = 1;
    }

    return fileno(std_console);
}

int libc_stdio_get_console(void) {
    if (std_console)
        return fileno(std_console);
    else
        return -1;
}