imfs_eval.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

         break;       /* Throw out the .. in this case */


	/*
	 * Am I at the root of this mounted filesystem?
	 */

        if (pathloc->node_access == pathloc->mt_entry->mt_fs_root.node_access){

          /*
	   *  Am I at the root of all filesystems?
	   */

          if ( pathloc->node_access == rtems_filesystem_root.node_access ) {
            break; 

	  } else {
            newloc = pathloc->mt_entry->mt_point_node;
            *pathloc = newloc;
            return (*pathloc->ops->evalformake_h)( &path[i-len], pathloc, name );
	  }
	} else {

          if ( !node->Parent )
            rtems_set_errno_and_return_minus_one( ENOENT );

          node = node->Parent;
	}

        pathloc->node_access = node;
        break;

      case IMFS_NAME:

	if ( node->type == IMFS_HARD_LINK ) {

          result = IMFS_evaluate_link( pathloc, 0 );
          if ( result == -1 )
            return -1;

	} else if ( node->type == IMFS_SYM_LINK ) {

          result = IMFS_evaluate_link( pathloc, 0 );

          if ( result == -1 )
            return -1;
	}

        node = pathloc->node_access;
        if ( !node )
          rtems_set_errno_and_return_minus_one( ENOTDIR ); 

        /*
         * Only a directory can be decended into.
	 */

        if ( node->type != IMFS_DIRECTORY )
          rtems_set_errno_and_return_minus_one( ENOTDIR );

	/*
	 * If we are at a node that is a mount point. Set loc to the
	 * new fs root node and let them finish evaluating the path.
	 */

        if ( node->info.directory.mt_fs != NULL ) {
          newloc  = node->info.directory.mt_fs->mt_fs_root;
          *pathloc = newloc;
          return (*pathloc->ops->evalformake_h)( &path[i-len], pathloc, name );
	}

	/*
	 * Otherwise find the token name in the present location.
	 */

        node = IMFS_find_match_in_dir( node, token );

	/*
	 * If there is no node we have found the name of the node we 
         * wish to create.
	 */

        if ( ! node )
          done = TRUE;
        else
          pathloc->node_access = node;

        break;
 
      case IMFS_NO_MORE_PATH:
        rtems_set_errno_and_return_minus_one( EEXIST );
        break;

      case IMFS_INVALID_TOKEN:
        rtems_set_errno_and_return_minus_one( ENAMETOOLONG );
        break;

      case IMFS_CURRENT_DIR:
        break;
    }
  }

  *name = &path[ i - len ];
   
  /*
   * We have evaluated the path as far as we can.
   * Verify there is not any invalid stuff at the end of the name. 
   */

  for( ; path[i] != '\0'; i++) {
    if ( !IMFS_is_separator( path[ i ] ) ) 
      rtems_set_errno_and_return_minus_one( ENOENT );
  }

  /* 
   * Verify we can execute and write to this directory.
   */

  result = IMFS_Set_handlers( pathloc );

  /*
   * The returned node must be a directory
   */
  node = pathloc->node_access;
  if ( node->type != IMFS_DIRECTORY )
    rtems_set_errno_and_return_minus_one( ENOTDIR );

  /*
   * We must have Write and execute permission on the returned node.
   */

  if ( !IMFS_evaluate_permission( pathloc, RTEMS_LIBIO_PERMS_WX ) )
    rtems_set_errno_and_return_minus_one( EACCES );
  
  return result;
}


/*
 *  IMFS_eval_path
 *
 *  The following routine evaluate path for a node that wishes to be
 *  accessed with mode.  pathloc is returned with a pointer to the
 *  node to be accessed.
 */

int IMFS_eval_path(  
  const char                        *pathname,     /* IN     */
  int                                flags,        /* IN     */
  rtems_filesystem_location_info_t  *pathloc       /* IN/OUT */
)
{
  int                                 i = 0;
  int                                 len;
  IMFS_token_types                    type = IMFS_CURRENT_DIR;
  char                                token[ IMFS_NAME_MAX + 1 ];
  rtems_filesystem_location_info_t    newloc;
  IMFS_jnode_t                       *node;
  int                                 result; 

  if ( !rtems_libio_is_valid_perms( flags ) ) {
    assert( 0 );
    rtems_set_errno_and_return_minus_one( EIO );    
  }

  /*
   *  This was filled in by the caller and is valid in the 
   *  mount table.
   */

  node = pathloc->node_access;

  /*
   *  Evaluate all tokens until we are done or an error occurs.
   */

  while( (type != IMFS_NO_MORE_PATH) && (type != IMFS_INVALID_TOKEN) ) {

    type = IMFS_get_token( &pathname[i], token, &len );
    i +=  len;
    
    if ( !pathloc->node_access )
      rtems_set_errno_and_return_minus_one( ENOENT );

    /*
     * I cannot move out of this directory without execute permission.
     */
    if ( type != IMFS_NO_MORE_PATH )
      if ( node->type == IMFS_DIRECTORY )
        if ( !IMFS_evaluate_permission( pathloc, RTEMS_LIBIO_PERMS_SEARCH ) )
           rtems_set_errno_and_return_minus_one( EACCES );

    node = pathloc->node_access;

    switch( type ) {
      case IMFS_UP_DIR:
       /*
        *  Am I at the root of all filesystems? (chroot'ed?)
	*/

       if ( pathloc->node_access == rtems_filesystem_root.node_access )
         break;       /* Throw out the .. in this case */

	/*
	 *  Am I at the root of this mounted filesystem?
	 */

        if (pathloc->node_access == 
            pathloc->mt_entry->mt_fs_root.node_access) {

          /*
	   *  Am I at the root of all filesystems?
	   */

          if ( pathloc->node_access == rtems_filesystem_root.node_access ) {
            break;       /* Throw out the .. in this case */
	  } else {
            newloc = pathloc->mt_entry->mt_point_node;
            *pathloc = newloc;
            return (*pathloc->ops->evalpath_h)(&(pathname[i-len]),flags,pathloc);
	  }
	} else {

          if ( !node->Parent )
            rtems_set_errno_and_return_minus_one( ENOENT );

          node = node->Parent;
          pathloc->node_access = node;

	}

        pathloc->node_access = node;
        break;

      case IMFS_NAME:
	/*
	 *  If we are at a link follow it.
	 */        

	if ( node->type == IMFS_HARD_LINK ) {

          IMFS_evaluate_hard_link( pathloc, 0 );

          node = pathloc->node_access;
          if ( !node )
            rtems_set_errno_and_return_minus_one( ENOTDIR );

	} else if ( node->type == IMFS_SYM_LINK ) {

          result = IMFS_evaluate_sym_link( pathloc, 0 );

          node = pathloc->node_access;
          if ( result == -1 )
            return -1;
	}

       /*
        *  Only a directory can be decended into.
        */

       if ( node->type != IMFS_DIRECTORY )
          rtems_set_errno_and_return_minus_one( ENOTDIR );

	/*
	 *  If we are at a node that is a mount point. Set loc to the
	 *  new fs root node and let them finish evaluating the path.
	 */

        if ( node->info.directory.mt_fs != NULL ) {
          newloc   = node->info.directory.mt_fs->mt_fs_root;
          *pathloc = newloc;
          return (*pathloc->ops->evalpath_h)( &pathname[i-len], flags, pathloc );
	}

	/*
	 *  Otherwise find the token name in the present location.
	 */

        node = IMFS_find_match_in_dir( node, token );
        if ( !node )
          rtems_set_errno_and_return_minus_one( ENOENT );

	/*
	 *  Set the node access to the point we have found.
	 */

        pathloc->node_access = node;
        break;

      case IMFS_NO_MORE_PATH:
      case IMFS_CURRENT_DIR:
        break;

      case IMFS_INVALID_TOKEN:
        rtems_set_errno_and_return_minus_one( ENAMETOOLONG );
        break;

    }
  }

  /*
   *  Always return the root node.
   *
   *  If we are at a node that is a mount point. Set loc to the
   *  new fs root node and let let the mounted filesystem set the handlers.
   *
   *  NOTE: The behavior of stat() on a mount point appears to be questionable.
   */

  if ( node->type == IMFS_DIRECTORY ) {
    if ( node->info.directory.mt_fs != NULL ) {
      newloc   = node->info.directory.mt_fs->mt_fs_root;
      *pathloc = newloc;
      return (*pathloc->ops->evalpath_h)( &pathname[i-len], flags, pathloc );
    } else {
      result = IMFS_Set_handlers( pathloc );
    }
  } else {
    result = IMFS_Set_handlers( pathloc );
  }

  /*
   * Verify we have the correct permissions for this node.
   */

  if ( !IMFS_evaluate_permission( pathloc, flags ) )
    rtems_set_errno_and_return_minus_one( EACCES );

  return result;
}