xnu-3247.1.106.tar.gz

[apple/xnu.git] / bsd / miscfs / devfs / devfsdefs.h

/*
 * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright 1997,1998 Julian Elischer.  All rights reserved.
 * julian@freebsd.org
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * devfsdefs.h
 */
/*
 * NOTICE: This file was modified by McAfee Research in 2004 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */

/*
 * HISTORY
 *  8-April-1999 Dieter Siegmund (dieter@apple.com)
 *	Ported to from FreeBSD 3.1
 *	Removed unnecessary/unused defines
 *	Renamed structures/elements to clarify usage in code.
 */

#ifndef __DEVFS_DEVFSDEFS_H__
#define __DEVFS_DEVFSDEFS_H__

#include  <sys/appleapiopts.h>

#include <security/mac.h>

__BEGIN_DECLS
#ifdef __APPLE_API_PRIVATE
#define DEVMAXNAMESIZE 	32 		/* XXX */
#define DEVMAXPATHSIZE 	128		/* XXX */

typedef enum {
    DEV_DIR,
    DEV_BDEV,
    DEV_CDEV,
    DEV_SLNK,
#if FDESC
    DEV_DEVFD
#endif /* FDESC */
} devfstype_t;

extern int (**devfs_vnodeop_p)(void *);	/* our own vector array for dirs */
extern int (**devfs_spec_vnodeop_p)(void *); /* our own vector array for devs */
extern struct vfsops devfs_vfsops;

typedef	struct devnode		devnode_t;
typedef struct devdirent 	devdirent_t;
typedef union devnode_type 	devnode_type_t;

struct devfs_stats {
    int			nodes;
    int			entries;
    int			mounts;
    int			stringspace;
};

union devnode_type {
    dev_t		dev;
    struct {
	devdirent_t *	dirlist;
	devdirent_t * *	dirlast;
	devnode_t *	parent;
	devdirent_t *	myname;		/* my entry in .. */
	int		entrycount;
    }Dir;
    struct {
	char *		name;	/* must be allocated separately */
	int		namelen;
    }Slnk;
};

#define DEV_MAX_VNODE_RETRY  8          /* Max number of retries when we try to
                                           get a vnode for the devnode */
struct devnode
{
    devfstype_t		dn_type;
    /* 
     * Number of vnodes that point to this devnode.  Note, we do not
     * add another reference for a lookup which finds an existing
     * vnode; a reference is added when a vnode is created and removed
     * when a vnode is reclaimed.  A devnode will not be freed while
     * there are outstanding references.  A refcount can be added to
     * prevent the free of a devnode in situations where there is not
     * guaranteed to be a vnode holding a ref, but it is important to
	 * make sure that a deferred delete eventually happens if it is
 	 * blocked behind that reference.
     */
    int			dn_refcount;
    u_short		dn_mode;
    uid_t		dn_uid; 
    gid_t		dn_gid;
    struct timespec	dn_atime;/* time of last access */
    struct timespec	dn_mtime;/* time of last modification */
    struct timespec	dn_ctime;/* time file changed */
    int	(***dn_ops)(void *);/* yuk... pointer to pointer(s) to funcs */
    int			dn_links;/* how many file links does this node have? */
    struct devfsmount *	dn_dvm; /* the mount structure for this 'plane' */
    struct vnode *	dn_vn;	/* address of last vnode that represented us */
    int			dn_len;   /* of any associated info (e.g. dir data) */
    devdirent_t *	dn_linklist;/* circular list of hardlinks to this node */
    devnode_t *		dn_nextsibling;	/* the list of equivalent nodes */
    devnode_t * *	dn_prevsiblingp;/* backpointer for the above */
    devnode_type_t	dn_typeinfo;
    int			dn_change;
    int			dn_update;
    int			dn_access;
    int			dn_lflags;
    ino_t		dn_ino;
    int			(*dn_clone)(dev_t dev, int action); /* get minor # */
    struct label *	dn_label;	/* security label */
};

#define	DN_DELETE		0x02
#define	DN_CREATE		0x04
#define	DN_CREATEWAIT		0x08


struct devdirent
{
    /*-----------------------directory entry fields-------------*/
    char		de_name[DEVMAXNAMESIZE];
    devnode_t *		de_dnp;		/* the "inode" (devnode) pointer */
    devnode_t *		de_parent;	/* backpointer to the directory itself */
    devdirent_t *	de_next;	/* next object in this directory */
    devdirent_t *	*de_prevp;	/* previous pointer in directory linked list */
    devdirent_t *	de_nextlink;	/* next hardlink to this node */
    devdirent_t *	*de_prevlinkp;	/* previous hardlink pointer for this node */
};

extern devdirent_t * 		dev_root;
extern struct devfs_stats	devfs_stats;
extern lck_mtx_t	  	devfs_mutex;
extern lck_mtx_t	  	devfs_attr_mutex;

/*
 * Rules for front nodes:
 * Dirs hava a strict 1:1 relationship with their OWN devnode
 * Symlinks similarly
 * Device Nodes ALWAYS point to the devnode that is linked
 * to the Backing node. (with a ref count)
 */

/*
 * DEVFS specific per/mount information, used to link a monted fs to a
 * particular 'plane' of front nodes.
 */
struct devfsmount
{
    struct mount *	mount;	/* vfs mount struct for this fs	*/
    devdirent_t *	plane_root;/* the root of this 'plane'	*/
};

/*
 * Prototypes for DEVFS virtual filesystem operations
 */
#include <sys/lock.h>
#include <miscfs/devfs/devfs_proto.h>
#include <libkern/OSAtomic.h>		/* required for OSAddAtomic() */

//#define HIDDEN_MOUNTPOINT	1

/* misc */
#define M_DEVFSNAME	M_DEVFS
#define M_DEVFSNODE	M_DEVFS
#define M_DEVFSMNT	M_DEVFS

#define VTODN(vp)	((devnode_t *)(vp)->v_data)

#define DEVFS_LOCK()	lck_mtx_lock(&devfs_mutex)
#define DEVFS_UNLOCK()	lck_mtx_unlock(&devfs_mutex)

#define DEVFS_ATTR_LOCK_SPIN()	lck_mtx_lock_spin(&devfs_attr_mutex);
#define DEVFS_ATTR_UNLOCK()	lck_mtx_unlock(&devfs_attr_mutex);

/*
 * XXX all the (SInt32 *) casts below assume sizeof(int) == sizeof(long)
 */
static __inline__ void
DEVFS_INCR_ENTRIES(void)
{
    OSAddAtomic(1, &devfs_stats.entries);
}

static __inline__ void
DEVFS_DECR_ENTRIES(void)
{
    OSAddAtomic(-1, &devfs_stats.entries);
}

static __inline__ void
DEVFS_INCR_NODES(void)
{
    OSAddAtomic(1, &devfs_stats.nodes);
}

static __inline__ void
DEVFS_DECR_NODES(void)
{
    OSAddAtomic(-1, &devfs_stats.nodes);
}

static __inline__ void
DEVFS_INCR_MOUNTS(void)
{
    OSAddAtomic(1, &devfs_stats.mounts);
}

static __inline__ void
DEVFS_DECR_MOUNTS(void)
{
    OSAddAtomic(-1, &devfs_stats.mounts);
}

static __inline__ void
DEVFS_INCR_STRINGSPACE(int space)
{
    OSAddAtomic(space, &devfs_stats.stringspace);
}

static __inline__ void
DEVFS_DECR_STRINGSPACE(int space)
{
    OSAddAtomic(-space, &devfs_stats.stringspace);
}

/* 
 * Access, change, and modify times are protected by a separate lock,
 * which allows tty times to be updated (no more than once per second)
 * in the I/O path without too much fear of contention.
 *
 * For getattr, update times to current time if the last update was recent; 
 * preserve  legacy behavior that frequent stats can yield sub-second resolutions.  
 * If the last time is old, however, we know that the event that triggered
 * the need for an update was no more than 1s after the last update.  In that case,
 * use (last update + 1s) as the time, avoiding the illusion that last update happened
 * much later than it really did.
 */
#define DEVFS_LAZY_UPDATE_SECONDS	1

#define DEVFS_UPDATE_CHANGE		0x1
#define DEVFS_UPDATE_MOD		0x2
#define DEVFS_UPDATE_ACCESS		0x4

static __inline__ void
dn_copy_times(devnode_t * target, devnode_t * source)
{
    DEVFS_ATTR_LOCK_SPIN();
    target->dn_atime = source->dn_atime;
    target->dn_mtime = source->dn_mtime;
    target->dn_ctime = source->dn_ctime;
    DEVFS_ATTR_UNLOCK();
    return;
}

#ifdef BSD_KERNEL_PRIVATE
int 	devfs_make_symlink(devnode_t *dir_p, char *name, int mode, char *target, devdirent_t **newent);
#endif /* BSD_KERNEL_PRIVATE */

#endif /* __APPLE_API_PRIVATE */

__END_DECLS

#endif /* __DEVFS_DEVFSDEFS_H__ */