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/11/sys/fs/pseudofs/pseudofs.h 325104 2017-10-29 14:57:58Z markj $
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;
84
85/*
86 * Init / uninit callback
87 */
88#define PFS_INIT_ARGS \
89	struct pfs_info *pi, struct vfsconf *vfc
90#define PFS_INIT_ARGNAMES \
91	pi, vfc
92#define PFS_INIT_PROTO(name) \
93	int name(PFS_INIT_ARGS);
94typedef int (*pfs_init_t)(PFS_INIT_ARGS);
95
96/*
97 * Filler callback
98 * Called with proc held but unlocked
99 */
100#define PFS_FILL_ARGS \
101	struct thread *td, struct proc *p, struct pfs_node *pn, \
102	struct sbuf *sb, struct uio *uio
103#define PFS_FILL_ARGNAMES \
104	td, p, pn, sb, uio
105#define PFS_FILL_PROTO(name) \
106	int name(PFS_FILL_ARGS);
107typedef int (*pfs_fill_t)(PFS_FILL_ARGS);
108
109/*
110 * Attribute callback
111 * Called with proc locked
112 */
113struct vattr;
114#define PFS_ATTR_ARGS \
115	struct thread *td, struct proc *p, struct pfs_node *pn, \
116	struct vattr *vap
117#define PFS_ATTR_ARGNAMES \
118	td, p, pn, vap
119#define PFS_ATTR_PROTO(name) \
120	int name(PFS_ATTR_ARGS);
121typedef int (*pfs_attr_t)(PFS_ATTR_ARGS);
122
123/*
124 * Visibility callback
125 * Called with proc locked
126 */
127#define PFS_VIS_ARGS \
128	struct thread *td, struct proc *p, struct pfs_node *pn
129#define PFS_VIS_ARGNAMES \
130	td, p, pn
131#define PFS_VIS_PROTO(name) \
132	int name(PFS_VIS_ARGS);
133typedef int (*pfs_vis_t)(PFS_VIS_ARGS);
134
135/*
136 * Ioctl callback
137 * Called with proc locked
138 */
139#define PFS_IOCTL_ARGS \
140	struct thread *td, struct proc *p, struct pfs_node *pn, \
141	unsigned long cmd, void *data
142#define PFS_IOCTL_ARGNAMES \
143	td, p, pn, cmd, data
144#define PFS_IOCTL_PROTO(name) \
145	int name(PFS_IOCTL_ARGS);
146typedef int (*pfs_ioctl_t)(PFS_IOCTL_ARGS);
147
148/*
149 * Getextattr callback
150 * Called with proc locked
151 */
152#define PFS_GETEXTATTR_ARGS \
153	struct thread *td, struct proc *p, struct pfs_node *pn, \
154	int attrnamespace, const char *name, struct uio *uio,	\
155	size_t *size, struct ucred *cred
156#define PFS_GETEXTATTR_ARGNAMES \
157	td, p, pn, attrnamespace, name, uio, size, cred
158#define PFS_GETEXTATTR_PROTO(name) \
159	int name(PFS_GETEXTATTR_ARGS);
160struct ucred;
161typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
162
163/*
164 * Last-close callback
165 * Called with proc locked
166 */
167#define PFS_CLOSE_ARGS \
168	struct thread *td, struct proc *p, struct pfs_node *pn
169#define PFS_CLOSE_ARGNAMES \
170	td, p, pn
171#define PFS_CLOSE_PROTO(name) \
172	int name(PFS_CLOSE_ARGS);
173typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
174
175/*
176 * Destroy callback
177 */
178#define PFS_DESTROY_ARGS \
179	struct pfs_node *pn
180#define PFS_DESTROY_ARGNAMES \
181	pn
182#define PFS_DESTROY_PROTO(name) \
183	int name(PFS_DESTROY_ARGS);
184typedef int (*pfs_destroy_t)(PFS_DESTROY_ARGS);
185
186/*
187 * pfs_info: describes a pseudofs instance
188 *
189 * The pi_mutex is only used to avoid using the global subr_unit lock
190 * for unrhdr.  The rest of struct pfs_info is only modified during
191 * vfs_init() and vfs_uninit() of the consumer filesystem.
192 */
193struct pfs_info {
194	char			 pi_name[PFS_FSNAMELEN];
195	pfs_init_t		 pi_init;
196	pfs_init_t		 pi_uninit;
197
198	/* members below this line are initialized at run time */
199	struct pfs_node		*pi_root;
200	struct mtx		 pi_mutex;
201	struct unrhdr		*pi_unrhdr;
202};
203
204/*
205 * pfs_node: describes a node (file or directory) within a pseudofs
206 *
207 * - Fields marked (o) are protected by the node's own mutex.
208 * - Fields marked (p) are protected by the node's parent's mutex.
209 * - Remaining fields are not protected by any lock and are assumed to be
210 *   immutable once the node has been created.
211 *
212 * To prevent deadlocks, if a node's mutex is to be held at the same time
213 * as its parent's (e.g. when adding or removing nodes to a directory),
214 * the parent's mutex must always be acquired first.  Unfortunately, this
215 * is not enforcable by WITNESS.
216 */
217struct pfs_node {
218	char			 pn_name[PFS_NAMELEN];
219	pfs_type_t		 pn_type;
220	int			 pn_flags;
221	struct mtx		 pn_mutex;
222	void			*pn_data;		/* (o) */
223
224	pfs_fill_t		 pn_fill;
225	pfs_ioctl_t		 pn_ioctl;
226	pfs_close_t		 pn_close;
227	pfs_attr_t		 pn_attr;
228	pfs_vis_t		 pn_vis;
229	pfs_getextattr_t	 pn_getextattr;
230	pfs_destroy_t		 pn_destroy;
231
232	struct pfs_info		*pn_info;
233	u_int32_t		 pn_fileno;		/* (o) */
234
235	struct pfs_node		*pn_parent;		/* (o) */
236	struct pfs_node		*pn_nodes;		/* (o) */
237	struct pfs_node		*pn_next;		/* (p) */
238};
239
240/*
241 * VFS interface
242 */
243int		 pfs_mount	(struct pfs_info *pi, struct mount *mp);
244int		 pfs_cmount	(struct mntarg *ma, void *data, uint64_t flags);
245int		 pfs_unmount	(struct mount *mp, int mntflags);
246int		 pfs_root	(struct mount *mp, int flags,
247				 struct vnode **vpp);
248int		 pfs_statfs	(struct mount *mp, struct statfs *sbp);
249int		 pfs_init	(struct pfs_info *pi, struct vfsconf *vfc);
250int		 pfs_uninit	(struct pfs_info *pi, struct vfsconf *vfc);
251
252/*
253 * Directory structure construction and manipulation
254 */
255struct pfs_node	*pfs_create_dir	(struct pfs_node *parent, const char *name,
256				 pfs_attr_t attr, pfs_vis_t vis,
257				 pfs_destroy_t destroy, int flags);
258struct pfs_node	*pfs_create_file(struct pfs_node *parent, const char *name,
259				 pfs_fill_t fill, pfs_attr_t attr,
260				 pfs_vis_t vis, pfs_destroy_t destroy,
261				 int flags);
262struct pfs_node	*pfs_create_link(struct pfs_node *parent, const char *name,
263				 pfs_fill_t fill, pfs_attr_t attr,
264				 pfs_vis_t vis, pfs_destroy_t destroy,
265				 int flags);
266struct pfs_node	*pfs_find_node	(struct pfs_node *parent, const char *name);
267void		 pfs_purge	(struct pfs_node *pn);
268int		 pfs_destroy	(struct pfs_node *pn);
269
270/*
271 * Now for some initialization magic...
272 */
273#define PSEUDOFS(name, version, jflag)					\
274									\
275static struct pfs_info name##_info = {					\
276	#name,								\
277	name##_init,							\
278	name##_uninit,							\
279};									\
280									\
281static int								\
282_##name##_mount(struct mount *mp) {					\
283        if (jflag && !prison_allow(curthread->td_ucred, jflag))		\
284                return (EPERM);						\
285	return (pfs_mount(&name##_info, mp));				\
286}									\
287									\
288static int								\
289_##name##_init(struct vfsconf *vfc) {					\
290	return (pfs_init(&name##_info, vfc));				\
291}									\
292									\
293static int								\
294_##name##_uninit(struct vfsconf *vfc) {					\
295	return (pfs_uninit(&name##_info, vfc));				\
296}									\
297									\
298static struct vfsops name##_vfsops = {					\
299	.vfs_cmount =		pfs_cmount,				\
300	.vfs_init =		_##name##_init,				\
301	.vfs_mount =		_##name##_mount,			\
302	.vfs_root =		pfs_root,				\
303	.vfs_statfs =		pfs_statfs,				\
304	.vfs_uninit =		_##name##_uninit,			\
305	.vfs_unmount =		pfs_unmount,				\
306};									\
307VFS_SET(name##_vfsops, name, VFCF_SYNTHETIC | (jflag ? VFCF_JAIL : 0));	\
308MODULE_VERSION(name, version);						\
309MODULE_DEPEND(name, pseudofs, 1, 1, 1);
310
311#endif
312