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/* file.c -- Definition of functions and structures for

   peripheral to communicate with host through files

   Copyright (C) 2002 Richard Prescott <rip@step.polymtl.ca>

This file is part of OpenRISC 1000 Architectural Simulator.

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., 675 Mass Ave, Cambridge, MA 02139, USA. */

#define _GNU_SOURCE     /* for strndup */

#include <sys/types.h>  /* open() */

#include <sys/stat.h>   /* open() */

#include <fcntl.h>      /* open() */

#include <malloc.h>     /* calloc(), free() */

#include <string.h>     /* strndup(), strchr() */

#include <errno.h>      /* errno */

#include <unistd.h>     /* close() */

#include "channel.h"    /* struct channel_ops */

#include "fd.h"         /* struct fd_channel, fd_read(), fd_write() */

struct file_channel

{

        struct fd_channel fds;

        char * namein;

        char * nameout;

};

static void * file_init(const char * args)

{

        struct file_channel * retval;

        char * nameout;

        if(!args)

        {

                errno = EINVAL;

                return NULL;

        }

        retval = (struct file_channel*)calloc(1, sizeof(struct file_channel));

        if(!retval)

        {

                return NULL;

        }

        retval->fds.fdin  = -1;

        retval->fds.fdout = -1;

        nameout = strchr(args, ',');

        if(nameout)

        {

                retval->namein  = strndup(args, nameout - args);

                retval->nameout = strdup(nameout+1);

        }

        else

        {

                retval->nameout = retval->namein  = strdup(args);

        }

        return (void*)retval;

}

static int file_open(void * data)

{

        struct file_channel * files = (struct file_channel *)data;

        if(!files)

        {

                errno = ENODEV;

                return -1;

        }

        if(files->namein == files->nameout)

        {

                /* if we have the same name in and out

                 * it cannot (logically) be a regular files.

                 * so we wont create one

                 */

                files->fds.fdin = files->fds.fdout = open(files->namein, O_RDWR);

                return files->fds.fdin < 0 ? -1 : 0;

        }

        files->fds.fdin = open(files->namein, O_RDONLY | O_CREAT, 0664);

        if(files->fds.fdin < 0)

                return -1;

        files->fds.fdout = open(files->nameout, O_WRONLY | O_CREAT, 0664);

        if(files->fds.fdout < 0)

        {

                close(files->fds.fdout);

                files->fds.fdout = -1;

                return -1;

        }

        return 0;

}

static void file_close(void * data)

{

        struct file_channel * files = (struct file_channel *)data;

        if(files->fds.fdin != files->fds.fdout)

                close(files->fds.fdin);

        close(files->fds.fdout);

        files->fds.fdin  = -1;

        files->fds.fdout = -1;

}

static void file_free(void * data)

{

        struct file_channel * files = (struct file_channel *)data;

        if(files->namein != files->nameout)

                free(files->namein);

        free(files->nameout);

        free(files);

}

struct channel_ops file_channel_ops =

{

        init:   file_init,

        open:   file_open,

        close:  file_close,

        read:   fd_read,

        write:  fd_write,

        free:   file_free,

};

/*

 * Local variables:

 * c-file-style: "linux"

 * End:

 */