/*
 * Copyright (c) 2012 embedded brains GmbH.  All rights reserved.
 *
 *  embedded brains GmbH
 *  Obere Lagerstr. 30
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.com/license/LICENSE.
 */

#if HAVE_CONFIG_H
  #include "config.h"
#endif

#include <rtems/libio_.h>

bool rtems_filesystem_check_access(
  int eval_flags,
  mode_t node_mode,
  uid_t node_uid,
  gid_t node_gid
)
{
  mode_t perm_flags = eval_flags & RTEMS_LIBIO_PERMS_RWX;
  uid_t task_uid = geteuid();

  if (task_uid == 0 || task_uid == node_uid) {
    perm_flags <<= 6;
  } else {
    gid_t task_gid = getegid();

    if (task_gid == 0 || task_gid == node_gid) {
      perm_flags <<= 3;
    } else {
      perm_flags <<= 0;
    }
  }

  return (perm_flags & node_mode) == perm_flags;
}

bool rtems_filesystem_eval_path_check_access(
  rtems_filesystem_eval_path_context_t *ctx,
  int eval_flags,
  mode_t node_mode,
  uid_t node_uid,
  gid_t node_gid
)
{
  bool access_ok = rtems_filesystem_check_access(
    eval_flags,
    node_mode,
    node_uid,
    node_gid
  );

  if (!access_ok) {
    rtems_filesystem_eval_path_error(ctx, EACCES);
  }

  return access_ok;
}