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

   peripheral to communicate with host through file descriptors

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

   Copyright (C) 2008 Embecosm Limited

   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

   This file is part of Or1ksim, the 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 3 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, see <http://www.gnu.org/licenses/>.  */

/* This program is commented throughout in a fashion suitable for processing

   with Doxygen. */

/* Autoconf and/or portability configuration */

#include "config.h"

#include "port.h"

/* System includes */

#include <stdlib.h>

#include <sys/types.h>

#include <sys/time.h>

#include <unistd.h>

#include <errno.h>

#include <stdio.h>

/* Package includes */

#include "fd.h"

#include "channel.h"

#include "generic.h"

/* Forward declarations of static functions */

static void *fd_init (const char *args);

static int   fd_isok (void *data);

static char *fd_status (void *data);

/*! Global data structure representing the operations for communicating

  through a file descriptor channel */

struct channel_ops  fd_channel_ops = {

        .init   = fd_init,

        .open   = generic_open,

        .close  = generic_close,

        .read   = fd_read,

        .write  = fd_write,

        .free   = generic_free,

        .isok   = fd_isok,

        .status = fd_status,

};

static void *

fd_init (const char *args)

{

  struct fd_channel *retval;

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

  if (!retval)

    {

      return NULL;

    }

  retval->fdin = atoi (args);   /* so 0 if garbage */

  /* TODO: strtoul */

  args = strchr (args, ',');

  if (args)

    {

      retval->fdout = atoi (args + 1);

    }

  else

    {

      retval->fdout = retval->fdin;

    }

  return (void *) retval;

}

int

fd_read (void *data, char *buffer, int size)

{

  struct fd_channel *fds = (struct fd_channel *) data;

  struct timeval timeout = { 0, 0 };

  fd_set rfds;

  int retval;

  if (!fds)

    {

      errno = ENODEV;

      return -1;

    }

  /* Loop, to allow for select being interrupted */

  do

    {

      FD_ZERO (&rfds);

      FD_SET (fds->fdin, &rfds);

      retval = select (fds->fdin + 1, &rfds, NULL, NULL, &timeout);

    }

  while ((retval < 0) && (EINTR == errno));

  if (retval <= 0)

    return retval;

  /* Loop, to allow for select being interrupted */

  do

    {

      retval = read (fds->fdin, buffer, size);

    }

  while ((retval < 0) && (EINTR == errno));

  return retval;

}

int

fd_write (void *data, const char *buffer, int size)

{

  struct fd_channel *fds = (struct fd_channel *) data;

  if (fds)

    {

      return write (fds->fdout, buffer, size);

    }

  errno = ENODEV;

  return -1;

}

static int

fd_isok (void *data)

{

  struct fd_channel *fds = (struct fd_channel *) data;

  if (fds)

    {

      return fds->fdout != -1 && fds->fdin != -1;

    }

  return 0;

}

static int

fd_status_fd (int fd, char *str, int size)

{

  if (fd == -1)

    return snprintf (str, size, "closed");

  return snprintf (str, size, "opened(fd=%d)", fd);

}

static char *

fd_status (void *data)

{

  static char retval[256];

  int index = 0;

  struct fd_channel *fds = (struct fd_channel *) data;

  if (fds)

    {

      index += snprintf (retval + index, sizeof (retval) - index, "in ");

      index +=

        fd_status_fd (fds->fdin, retval + index, sizeof (retval) - index);

      index += snprintf (retval + index, sizeof (retval) - index, "out ");

      index +=

        fd_status_fd (fds->fdout, retval + index, sizeof (retval) - index);

    }

  else

    {

      snprintf (retval, sizeof (retval), "(null)");

    }

  return retval;

}