1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2001 Dag-Erling Sm��rgrav
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer
12 *    in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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		128
54#define PFS_FSNAMELEN		16	/* equal to MFSNAMELEN */
55#define PFS_DELEN		(offsetof(struct dirent, d_name) + 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#define PFS_NOWAIT	0x0020 /* allow malloc to fail */
79#define PFS_AUTODRAIN	0x0040	/* sbuf_print can sleep to drain */
80
81/*
82 * Data structures
83 */
84struct pfs_info;
85struct pfs_node;
86
87/*
88 * Init / uninit callback
89 */
90#define PFS_INIT_ARGS \
91	struct pfs_info *pi, struct vfsconf *vfc
92#define PFS_INIT_ARGNAMES \
93	pi, vfc
94#define PFS_INIT_PROTO(name) \
95	int name(PFS_INIT_ARGS);
96typedef int (*pfs_init_t)(PFS_INIT_ARGS);
97
98/*
99 * Filler callback
100 * Called with proc held but unlocked
101 */
102#define PFS_FILL_ARGS \
103	struct thread *td, struct proc *p, struct pfs_node *pn, \
104	struct sbuf *sb, struct uio *uio
105#define PFS_FILL_ARGNAMES \
106	td, p, pn, sb, uio
107#define PFS_FILL_PROTO(name) \
108	int name(PFS_FILL_ARGS);
109typedef int (*pfs_fill_t)(PFS_FILL_ARGS);
110
111/*
112 * Attribute callback
113 * Called with proc locked
114 */
115struct vattr;
116#define PFS_ATTR_ARGS \
117	struct thread *td, struct proc *p, struct pfs_node *pn, \
118	struct vattr *vap
119#define PFS_ATTR_ARGNAMES \
120	td, p, pn, vap
121#define PFS_ATTR_PROTO(name) \
122	int name(PFS_ATTR_ARGS);
123typedef int (*pfs_attr_t)(PFS_ATTR_ARGS);
124
125/*
126 * Visibility callback
127 * Called with proc locked
128 */
129#define PFS_VIS_ARGS \
130	struct thread *td, struct proc *p, struct pfs_node *pn
131#define PFS_VIS_ARGNAMES \
132	td, p, pn
133#define PFS_VIS_PROTO(name) \
134	int name(PFS_VIS_ARGS);
135typedef int (*pfs_vis_t)(PFS_VIS_ARGS);
136
137/*
138 * Ioctl callback
139 * Called with proc locked
140 */
141#define PFS_IOCTL_ARGS \
142	struct thread *td, struct proc *p, struct pfs_node *pn, \
143	unsigned long cmd, void *data
144#define PFS_IOCTL_ARGNAMES \
145	td, p, pn, cmd, data
146#define PFS_IOCTL_PROTO(name) \
147	int name(PFS_IOCTL_ARGS);
148typedef int (*pfs_ioctl_t)(PFS_IOCTL_ARGS);
149
150/*
151 * Getextattr callback
152 * Called with proc locked
153 */
154#define PFS_GETEXTATTR_ARGS \
155	struct thread *td, struct proc *p, struct pfs_node *pn, \
156	int attrnamespace, const char *name, struct uio *uio,	\
157	size_t *size, struct ucred *cred
158#define PFS_GETEXTATTR_ARGNAMES \
159	td, p, pn, attrnamespace, name, uio, size, cred
160#define PFS_GETEXTATTR_PROTO(name) \
161	int name(PFS_GETEXTATTR_ARGS);
162struct ucred;
163typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
164
165/*
166 * Last-close callback
167 * Called with proc locked
168 */
169#define PFS_CLOSE_ARGS \
170	struct thread *td, struct proc *p, struct pfs_node *pn
171#define PFS_CLOSE_ARGNAMES \
172	td, p, pn
173#define PFS_CLOSE_PROTO(name) \
174	int name(PFS_CLOSE_ARGS);
175typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
176
177/*
178 * Destroy callback
179 */
180#define PFS_DESTROY_ARGS \
181	struct pfs_node *pn
182#define PFS_DESTROY_ARGNAMES \
183	pn
184#define PFS_DESTROY_PROTO(name) \
185	int name(PFS_DESTROY_ARGS);
186typedef int (*pfs_destroy_t)(PFS_DESTROY_ARGS);
187
188/*
189 * pfs_info: describes a pseudofs instance
190 *
191 * The pi_mutex is only used to avoid using the global subr_unit lock
192 * for unrhdr.  The rest of struct pfs_info is only modified during
193 * vfs_init() and vfs_uninit() of the consumer filesystem.
194 */
195struct pfs_info {
196	char			 pi_name[PFS_FSNAMELEN];
197	pfs_init_t		 pi_init;
198	pfs_init_t		 pi_uninit;
199
200	/* members below this line are initialized at run time */
201	struct pfs_node		*pi_root;
202	struct mtx		 pi_mutex;
203	struct unrhdr		*pi_unrhdr;
204};
205
206/*
207 * pfs_node: describes a node (file or directory) within a pseudofs
208 *
209 * - Fields marked (o) are protected by the node's own mutex.
210 * - Fields marked (p) are protected by the node's parent's mutex.
211 * - Remaining fields are not protected by any lock and are assumed to be
212 *   immutable once the node has been created.
213 *
214 * To prevent deadlocks, if a node's mutex is to be held at the same time
215 * as its parent's (e.g. when adding or removing nodes to a directory),
216 * the parent's mutex must always be acquired first.  Unfortunately, this
217 * is not enforcable by WITNESS.
218 */
219struct pfs_node {
220	pfs_type_t		 pn_type;
221	int			 pn_flags;
222	struct mtx		 pn_mutex;
223	void			*pn_data;		/* (o) */
224
225	pfs_fill_t		 pn_fill;
226	pfs_ioctl_t		 pn_ioctl;
227	pfs_close_t		 pn_close;
228	pfs_attr_t		 pn_attr;
229	pfs_vis_t		 pn_vis;
230	pfs_getextattr_t	 pn_getextattr;
231	pfs_destroy_t		 pn_destroy;
232
233	struct pfs_info		*pn_info;
234	u_int32_t		 pn_fileno;		/* (o) */
235
236	struct pfs_node		*pn_parent;		/* (o) */
237	struct pfs_node		*pn_nodes;		/* (o) */
238	struct pfs_node		*pn_last_node;		/* (o) */
239	struct pfs_node		*pn_next;		/* (p) */
240	char			 pn_name[];		/* Keep it last */
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, flags)					\
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	return (pfs_mount(&name##_info, mp));				\
287}									\
288									\
289static int								\
290_##name##_init(struct vfsconf *vfc) {					\
291	return (pfs_init(&name##_info, vfc));				\
292}									\
293									\
294static int								\
295_##name##_uninit(struct vfsconf *vfc) {					\
296	return (pfs_uninit(&name##_info, vfc));				\
297}									\
298									\
299static struct vfsops name##_vfsops = {					\
300	.vfs_cmount =		pfs_cmount,				\
301	.vfs_init =		_##name##_init,				\
302	.vfs_mount =		_##name##_mount,			\
303	.vfs_root =		pfs_root,				\
304	.vfs_statfs =		pfs_statfs,				\
305	.vfs_uninit =		_##name##_uninit,			\
306	.vfs_unmount =		pfs_unmount,				\
307};									\
308VFS_SET(name##_vfsops, name, VFCF_SYNTHETIC | flags);			\
309MODULE_VERSION(name, version);						\
310MODULE_DEPEND(name, pseudofs, 1, 1, 1);
311
312#endif
313