pseudofs.h revision 303907 
1/*-
2 * Copyright (c) 2001 Dag-Erling Co��dan Sm��rgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 *      $FreeBSD: stable/10/sys/fs/pseudofs/pseudofs.h 303907 2016-08-10 12:36:54Z kib $
29 */
30
31#ifndef _PSEUDOFS_H_INCLUDED
32#define _PSEUDOFS_H_INCLUDED
33
34#include <sys/jail.h>
35
36/*
37 * Opaque structures
38 */
39struct mntarg;
40struct mount;
41struct nameidata;
42struct proc;
43struct sbuf;
44struct statfs;
45struct thread;
46struct uio;
47struct vfsconf;
48struct vnode;
49
50/*
51 * Limits and constants
52 */
53#define PFS_NAMELEN		24
54#define PFS_FSNAMELEN		16	/* equal to MFSNAMELEN */
55#define PFS_DELEN		(8 + PFS_NAMELEN)
56
57typedef enum {
58	pfstype_none = 0,
59	pfstype_root,
60	pfstype_dir,
61	pfstype_this,
62	pfstype_parent,
63	pfstype_file,
64	pfstype_symlink,
65	pfstype_procdir
66} pfs_type_t;
67
68/*
69 * Flags
70 */
71#define PFS_RD		0x0001	/* readable */
72#define PFS_WR		0x0002	/* writeable */
73#define PFS_RDWR	(PFS_RD|PFS_WR)
74#define PFS_RAWRD	0x0004	/* raw reader */
75#define	PFS_RAWWR	0x0008	/* raw writer */
76#define PFS_RAW		(PFS_RAWRD|PFS_RAWWR)
77#define PFS_PROCDEP	0x0010	/* process-dependent */
78
79/*
80 * Data structures
81 */
82struct pfs_info;
83struct pfs_node;
84struct pfs_bitmap;
85
86/*
87 * Init / uninit callback
88 */
89#define PFS_INIT_ARGS \
90	struct pfs_info *pi, struct vfsconf *vfc
91#define PFS_INIT_ARGNAMES \
92	pi, vfc
93#define PFS_INIT_PROTO(name) \
94	int name(PFS_INIT_ARGS);
95typedef int (*pfs_init_t)(PFS_INIT_ARGS);
96
97/*
98 * Filler callback
99 * Called with proc held but unlocked
100 */
101#define PFS_FILL_ARGS \
102	struct thread *td, struct proc *p, struct pfs_node *pn, \
103	struct sbuf *sb, struct uio *uio
104#define PFS_FILL_ARGNAMES \
105	td, p, pn, sb, uio
106#define PFS_FILL_PROTO(name) \
107	int name(PFS_FILL_ARGS);
108typedef int (*pfs_fill_t)(PFS_FILL_ARGS);
109
110/*
111 * Attribute callback
112 * Called with proc locked
113 */
114struct vattr;
115#define PFS_ATTR_ARGS \
116	struct thread *td, struct proc *p, struct pfs_node *pn, \
117	struct vattr *vap
118#define PFS_ATTR_ARGNAMES \
119	td, p, pn, vap
120#define PFS_ATTR_PROTO(name) \
121	int name(PFS_ATTR_ARGS);
122typedef int (*pfs_attr_t)(PFS_ATTR_ARGS);
123
124struct pfs_bitmap;		/* opaque */
125
126/*
127 * Visibility callback
128 * Called with proc locked
129 */
130#define PFS_VIS_ARGS \
131	struct thread *td, struct proc *p, struct pfs_node *pn
132#define PFS_VIS_ARGNAMES \
133	td, p, pn
134#define PFS_VIS_PROTO(name) \
135	int name(PFS_VIS_ARGS);
136typedef int (*pfs_vis_t)(PFS_VIS_ARGS);
137
138/*
139 * Ioctl callback
140 * Called with proc locked
141 */
142#define PFS_IOCTL_ARGS \
143	struct thread *td, struct proc *p, struct pfs_node *pn, \
144	unsigned long cmd, void *data
145#define PFS_IOCTL_ARGNAMES \
146	td, p, pn, cmd, data
147#define PFS_IOCTL_PROTO(name) \
148	int name(PFS_IOCTL_ARGS);
149typedef int (*pfs_ioctl_t)(PFS_IOCTL_ARGS);
150
151/*
152 * Getextattr callback
153 * Called with proc locked
154 */
155#define PFS_GETEXTATTR_ARGS \
156	struct thread *td, struct proc *p, struct pfs_node *pn, \
157	int attrnamespace, const char *name, struct uio *uio,	\
158	size_t *size, struct ucred *cred
159#define PFS_GETEXTATTR_ARGNAMES \
160	td, p, pn, attrnamespace, name, uio, size, cred
161#define PFS_GETEXTATTR_PROTO(name) \
162	int name(PFS_GETEXTATTR_ARGS);
163struct ucred;
164typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
165
166/*
167 * Last-close callback
168 * Called with proc locked
169 */
170#define PFS_CLOSE_ARGS \
171	struct thread *td, struct proc *p, struct pfs_node *pn
172#define PFS_CLOSE_ARGNAMES \
173	td, p, pn
174#define PFS_CLOSE_PROTO(name) \
175	int name(PFS_CLOSE_ARGS);
176typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
177
178/*
179 * Destroy callback
180 */
181#define PFS_DESTROY_ARGS \
182	struct pfs_node *pn
183#define PFS_DESTROY_ARGNAMES \
184	pn
185#define PFS_DESTROY_PROTO(name) \
186	int name(PFS_DESTROY_ARGS);
187typedef int (*pfs_destroy_t)(PFS_DESTROY_ARGS);
188
189/*
190 * pfs_info: describes a pseudofs instance
191 *
192 * The pi_mutex is only used to avoid using the global subr_unit lock
193 * for unrhdr.  The rest of struct pfs_info is only modified during
194 * vfs_init() and vfs_uninit() of the consumer filesystem.
195 */
196struct pfs_info {
197	char			 pi_name[PFS_FSNAMELEN];
198	pfs_init_t		 pi_init;
199	pfs_init_t		 pi_uninit;
200
201	/* members below this line are initialized at run time */
202	struct pfs_node		*pi_root;
203	struct mtx		 pi_mutex;
204	struct unrhdr		*pi_unrhdr;
205};
206
207/*
208 * pfs_node: describes a node (file or directory) within a pseudofs
209 *
210 * - Fields marked (o) are protected by the node's own mutex.
211 * - Fields marked (p) are protected by the node's parent's mutex.
212 * - Remaining fields are not protected by any lock and are assumed to be
213 *   immutable once the node has been created.
214 *
215 * To prevent deadlocks, if a node's mutex is to be held at the same time
216 * as its parent's (e.g. when adding or removing nodes to a directory),
217 * the parent's mutex must always be acquired first.  Unfortunately, this
218 * is not enforcable by WITNESS.
219 */
220struct pfs_node {
221	char			 pn_name[PFS_NAMELEN];
222	pfs_type_t		 pn_type;
223	int			 pn_flags;
224	struct mtx		 pn_mutex;
225	void			*pn_data;		/* (o) */
226
227	pfs_fill_t		 pn_fill;
228	pfs_ioctl_t		 pn_ioctl;
229	pfs_close_t		 pn_close;
230	pfs_attr_t		 pn_attr;
231	pfs_vis_t		 pn_vis;
232	pfs_getextattr_t	 pn_getextattr;
233	pfs_destroy_t		 pn_destroy;
234
235	struct pfs_info		*pn_info;
236	u_int32_t		 pn_fileno;		/* (o) */
237
238	struct pfs_node		*pn_parent;		/* (o) */
239	struct pfs_node		*pn_nodes;		/* (o) */
240	struct pfs_node		*pn_next;		/* (p) */
241};
242
243/*
244 * VFS interface
245 */
246int		 pfs_mount	(struct pfs_info *pi, struct mount *mp);
247int		 pfs_cmount	(struct mntarg *ma, void *data, uint64_t flags);
248int		 pfs_unmount	(struct mount *mp, int mntflags);
249int		 pfs_root	(struct mount *mp, int flags,
250				 struct vnode **vpp);
251int		 pfs_statfs	(struct mount *mp, struct statfs *sbp);
252int		 pfs_init	(struct pfs_info *pi, struct vfsconf *vfc);
253int		 pfs_uninit	(struct pfs_info *pi, struct vfsconf *vfc);
254
255/*
256 * Directory structure construction and manipulation
257 */
258struct pfs_node	*pfs_create_dir	(struct pfs_node *parent, const char *name,
259				 pfs_attr_t attr, pfs_vis_t vis,
260				 pfs_destroy_t destroy, int flags);
261struct pfs_node	*pfs_create_file(struct pfs_node *parent, const char *name,
262				 pfs_fill_t fill, pfs_attr_t attr,
263				 pfs_vis_t vis, pfs_destroy_t destroy,
264				 int flags);
265struct pfs_node	*pfs_create_link(struct pfs_node *parent, const char *name,
266				 pfs_fill_t fill, pfs_attr_t attr,
267				 pfs_vis_t vis, pfs_destroy_t destroy,
268				 int flags);
269struct pfs_node	*pfs_find_node	(struct pfs_node *parent, const char *name);
270void		 pfs_purge	(struct pfs_node *pn);
271int		 pfs_destroy	(struct pfs_node *pn);
272
273/*
274 * Now for some initialization magic...
275 */
276#define PSEUDOFS(name, version, jflag)					\
277									\
278static struct pfs_info name##_info = {					\
279	#name,								\
280	name##_init,							\
281	name##_uninit,							\
282};									\
283									\
284static int								\
285_##name##_mount(struct mount *mp) {					\
286        if (jflag && !prison_allow(curthread->td_ucred, jflag))		\
287                return (EPERM);						\
288	return (pfs_mount(&name##_info, mp));				\
289}									\
290									\
291static int								\
292_##name##_init(struct vfsconf *vfc) {					\
293	return (pfs_init(&name##_info, vfc));				\
294}									\
295									\
296static int								\
297_##name##_uninit(struct vfsconf *vfc) {					\
298	return (pfs_uninit(&name##_info, vfc));				\
299}									\
300									\
301static struct vfsops name##_vfsops = {					\
302	.vfs_cmount =		pfs_cmount,				\
303	.vfs_init =		_##name##_init,				\
304	.vfs_mount =		_##name##_mount,			\
305	.vfs_root =		pfs_root,				\
306	.vfs_statfs =		pfs_statfs,				\
307	.vfs_uninit =		_##name##_uninit,			\
308	.vfs_unmount =		pfs_unmount,				\
309};									\
310VFS_SET(name##_vfsops, name, VFCF_SYNTHETIC | (jflag ? VFCF_JAIL : 0));	\
311MODULE_VERSION(name, version);						\
312MODULE_DEPEND(name, pseudofs, 1, 1, 1);
313
314#endif
315