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/* Hurd /proc filesystem, infrastructure for directories.
Copyright (C) 2010 Free Software Foundation, Inc.
This file is part of the GNU Hurd.
The GNU Hurd 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, or (at
your option) any later version.
The GNU Hurd 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. */
/* This module provides an abstraction layer for implementing simple
directories with (mostly) static contents. The user defines the
contents of the directory by providing a table of entries and various
optional callback functions. */
/* These operations define how a given entry will behave. Either can be
omitted, both from the entry-specific operations and from the
directory-wide defaults. */
struct procfs_dir_entry_ops
{
/* Called when this entry is looked up to create a corresponding node. */
struct node *(*make_node)(void *dir_hook, const void *entry_hook);
/* If this is provided and returns 0, this entry will be hidden. */
int (*exists)(void *dir_hook, const void *entry_hook);
};
/* Describes an individual directory entry, associating a NAME with
* arbitrary HOOK data and node-specific OPS. */
struct procfs_dir_entry
{
const char *name;
const void *hook;
struct procfs_dir_entry_ops ops;
};
/* Describes a complete directory. ENTRIES is a table terminated by a
null NAME field. ENTRY_OPS provides default operations for the
entries which don't specify them. The optional CLEANUP function
should release all the resources associated with the directory hook. */
struct procfs_dir_ops
{
const struct procfs_dir_entry *entries;
void (*cleanup)(void *dir_hook);
struct procfs_dir_entry_ops entry_ops;
};
/* Create and return a new node for the directory described in OPS.
The DIR_HOOK is passed the MAKE_NODE callback function of looked up
entries, as well as to the CLEANUP callback when the node is
destroyed. If not enough memory can be allocated, OPS->CLEANUP is
invoked immediately and NULL is returned. */
struct node *
procfs_dir_make_node (const struct procfs_dir_ops *ops, void *dir_hook);
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