xref: /freebsd/sys/fs/pseudofs/pseudofs.h (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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  *      $FreeBSD$
29  */
30 
31 #ifndef _PSEUDOFS_H_INCLUDED
32 #define _PSEUDOFS_H_INCLUDED
33 
34 /*
35  * Opaque structures
36  */
37 struct mntarg;
38 struct mount;
39 struct nameidata;
40 struct proc;
41 struct sbuf;
42 struct statfs;
43 struct thread;
44 struct uio;
45 struct vfsconf;
46 struct vnode;
47 
48 /*
49  * Limits and constants
50  */
51 #define PFS_NAMELEN		24
52 #define PFS_FSNAMELEN		16	/* equal to MFSNAMELEN */
53 #define PFS_DELEN		(8 + PFS_NAMELEN)
54 
55 typedef enum {
56 	pfstype_none = 0,
57 	pfstype_root,
58 	pfstype_dir,
59 	pfstype_this,
60 	pfstype_parent,
61 	pfstype_file,
62 	pfstype_symlink,
63 	pfstype_procdir
64 } pfs_type_t;
65 
66 /*
67  * Flags
68  */
69 #define PFS_RD		0x0001	/* readable */
70 #define PFS_WR		0x0002	/* writeable */
71 #define PFS_RDWR	(PFS_RD|PFS_WR)
72 #define PFS_RAWRD	0x0004	/* raw reader */
73 #define	PFS_RAWWR	0x0008	/* raw writer */
74 #define PFS_RAW		(PFS_RAWRD|PFS_RAWWR)
75 #define PFS_PROCDEP	0x0010	/* process-dependent */
76 
77 /*
78  * Data structures
79  */
80 struct pfs_info;
81 struct pfs_node;
82 struct pfs_bitmap;
83 
84 /*
85  * Init / uninit callback
86  */
87 #define PFS_INIT_ARGS \
88 	struct pfs_info *pi, struct vfsconf *vfc
89 #define PFS_INIT_ARGNAMES \
90 	pi, vfc
91 #define PFS_INIT_PROTO(name) \
92 	int name(PFS_INIT_ARGS);
93 typedef int (*pfs_init_t)(PFS_INIT_ARGS);
94 
95 /*
96  * Filler callback
97  * Called with proc held but unlocked
98  */
99 #define PFS_FILL_ARGS \
100 	struct thread *td, struct proc *p, struct pfs_node *pn, \
101 	struct sbuf *sb, struct uio *uio
102 #define PFS_FILL_ARGNAMES \
103 	td, p, pn, sb, uio
104 #define PFS_FILL_PROTO(name) \
105 	int name(PFS_FILL_ARGS);
106 typedef int (*pfs_fill_t)(PFS_FILL_ARGS);
107 
108 /*
109  * Attribute callback
110  * Called with proc locked
111  */
112 struct vattr;
113 #define PFS_ATTR_ARGS \
114 	struct thread *td, struct proc *p, struct pfs_node *pn, \
115 	struct vattr *vap
116 #define PFS_ATTR_ARGNAMES \
117 	td, p, pn, vap
118 #define PFS_ATTR_PROTO(name) \
119 	int name(PFS_ATTR_ARGS);
120 typedef int (*pfs_attr_t)(PFS_ATTR_ARGS);
121 
122 struct pfs_bitmap;		/* opaque */
123 
124 /*
125  * Visibility callback
126  * Called with proc locked
127  */
128 #define PFS_VIS_ARGS \
129 	struct thread *td, struct proc *p, struct pfs_node *pn
130 #define PFS_VIS_ARGNAMES \
131 	td, p, pn
132 #define PFS_VIS_PROTO(name) \
133 	int name(PFS_VIS_ARGS);
134 typedef int (*pfs_vis_t)(PFS_VIS_ARGS);
135 
136 /*
137  * Ioctl callback
138  * Called with proc locked
139  */
140 #define PFS_IOCTL_ARGS \
141 	struct thread *td, struct proc *p, struct pfs_node *pn, \
142 	unsigned long cmd, void *data
143 #define PFS_IOCTL_ARGNAMES \
144 	td, p, pn, cmd, data
145 #define PFS_IOCTL_PROTO(name) \
146 	int name(PFS_IOCTL_ARGS);
147 typedef int (*pfs_ioctl_t)(PFS_IOCTL_ARGS);
148 
149 /*
150  * Getextattr callback
151  * Called with proc locked
152  */
153 #define PFS_GETEXTATTR_ARGS \
154 	struct thread *td, struct proc *p, struct pfs_node *pn, \
155 	int attrnamespace, const char *name, struct uio *uio,	\
156 	size_t *size, struct ucred *cred
157 #define PFS_GETEXTATTR_ARGNAMES \
158 	td, p, pn, attrnamespace, name, uio, size, cred
159 #define PFS_GETEXTATTR_PROTO(name) \
160 	int name(PFS_GETEXTATTR_ARGS);
161 struct ucred;
162 typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
163 
164 /*
165  * Last-close callback
166  * Called with proc locked
167  */
168 #define PFS_CLOSE_ARGS \
169 	struct thread *td, struct proc *p, struct pfs_node *pn
170 #define PFS_CLOSE_ARGNAMES \
171 	td, p, pn
172 #define PFS_CLOSE_PROTO(name) \
173 	int name(PFS_CLOSE_ARGS);
174 typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
175 
176 /*
177  * Destroy callback
178  */
179 #define PFS_DESTROY_ARGS \
180 	struct pfs_node *pn
181 #define PFS_DESTROY_ARGNAMES \
182 	pn
183 #define PFS_DESTROY_PROTO(name) \
184 	int name(PFS_DESTROY_ARGS);
185 typedef int (*pfs_destroy_t)(PFS_DESTROY_ARGS);
186 
187 /*
188  * pfs_info: describes a pseudofs instance
189  *
190  * The pi_mutex is only used to avoid using the global subr_unit lock for
191  * unrhdr.  The rest of struct pfs_info is only modified while Giant is
192  * held (during vfs_init() and vfs_uninit()).
193  */
194 struct pfs_info {
195 	char			 pi_name[PFS_FSNAMELEN];
196 	pfs_init_t		 pi_init;
197 	pfs_init_t		 pi_uninit;
198 
199 	/* members below this line are initialized at run time*/
200 	struct pfs_node		*pi_root;
201 	struct mtx		 pi_mutex;
202 	struct unrhdr		*pi_unrhdr;
203 };
204 
205 /*
206  * pfs_node: describes a node (file or directory) within a pseudofs
207  *
208  * - Fields marked (o) are protected by the node's own mutex.
209  * - Fields marked (p) are protected by the node's parent's mutex.
210  * - Remaining fields are not protected by any lock and are assumed to be
211  *   immutable once the node has been created.
212  *
213  * To prevent deadlocks, if a node's mutex is to be held at the same time
214  * as its parent's (e.g. when adding or removing nodes to a directory),
215  * the parent's mutex must always be acquired first.  Unfortunately, this
216  * is not enforcable by WITNESS.
217  */
218 struct pfs_node {
219 	char			 pn_name[PFS_NAMELEN];
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_next;		/* (p) */
239 };
240 
241 /*
242  * VFS interface
243  */
244 int		 pfs_mount	(struct pfs_info *pi, struct mount *mp,
245 				 struct thread *td);
246 int		 pfs_cmount	(struct mntarg *ma, void *data, int flags,
247 				 struct thread *td);
248 int		 pfs_unmount	(struct mount *mp, int mntflags,
249 				 struct thread *td);
250 int		 pfs_root	(struct mount *mp, int flags,
251 				 struct vnode **vpp, struct thread *td);
252 int		 pfs_statfs	(struct mount *mp, struct statfs *sbp,
253 				 struct thread *td);
254 int		 pfs_init	(struct pfs_info *pi, struct vfsconf *vfc);
255 int		 pfs_uninit	(struct pfs_info *pi, struct vfsconf *vfc);
256 
257 /*
258  * Directory structure construction and manipulation
259  */
260 struct pfs_node	*pfs_create_dir	(struct pfs_node *parent, const char *name,
261 				 pfs_attr_t attr, pfs_vis_t vis,
262 				 pfs_destroy_t destroy, int flags);
263 struct pfs_node	*pfs_create_file(struct pfs_node *parent, const char *name,
264 				 pfs_fill_t fill, pfs_attr_t attr,
265 				 pfs_vis_t vis, pfs_destroy_t destroy,
266 				 int flags);
267 struct pfs_node	*pfs_create_link(struct pfs_node *parent, const char *name,
268 				 pfs_fill_t fill, pfs_attr_t attr,
269 				 pfs_vis_t vis, pfs_destroy_t destroy,
270 				 int flags);
271 struct pfs_node	*pfs_find_node	(struct pfs_node *parent, const char *name);
272 void		 pfs_purge	(struct pfs_node *pn);
273 int		 pfs_destroy	(struct pfs_node *pn);
274 
275 /*
276  * Now for some initialization magic...
277  */
278 #define PSEUDOFS(name, version)						\
279 									\
280 static struct pfs_info name##_info = {					\
281 	#name,								\
282 	name##_init,							\
283 	name##_uninit,							\
284 };									\
285 									\
286 static int								\
287 _##name##_mount(struct mount *mp, struct thread *td) {			\
288 	return pfs_mount(&name##_info, mp, td);				\
289 }									\
290 									\
291 static int								\
292 _##name##_init(struct vfsconf *vfc) {					\
293 	return pfs_init(&name##_info, vfc);				\
294 }									\
295 									\
296 static int								\
297 _##name##_uninit(struct vfsconf *vfc) {					\
298 	return pfs_uninit(&name##_info, vfc);				\
299 }									\
300 									\
301 static 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 };									\
310 VFS_SET(name##_vfsops, name, VFCF_SYNTHETIC);				\
311 MODULE_VERSION(name, version);						\
312 MODULE_DEPEND(name, pseudofs, 1, 1, 1);
313 
314 #endif
315