pseudofs.c revision 138495 
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: head/sys/fs/pseudofs/pseudofs.c 138495 2004-12-06 20:52:46Z phk $
29 */
30
31#include <sys/param.h>
32#include <sys/kernel.h>
33#include <sys/systm.h>
34#include <sys/lock.h>
35#include <sys/malloc.h>
36#include <sys/module.h>
37#include <sys/mount.h>
38#include <sys/mutex.h>
39#include <sys/proc.h>
40#include <sys/sbuf.h>
41#include <sys/sysctl.h>
42#include <sys/vnode.h>
43
44#include <fs/pseudofs/pseudofs.h>
45#include <fs/pseudofs/pseudofs_internal.h>
46
47static MALLOC_DEFINE(M_PFSNODES, "pfs_nodes", "pseudofs nodes");
48
49SYSCTL_NODE(_vfs, OID_AUTO, pfs, CTLFLAG_RW, 0,
50    "pseudofs");
51
52#if PFS_FSNAMELEN != MFSNAMELEN
53#error "PFS_FSNAMELEN is not equal to MFSNAMELEN"
54#endif
55
56/*
57 * Add a node to a directory
58 */
59static int
60_pfs_add_node(struct pfs_node *parent, struct pfs_node *node)
61{
62	KASSERT(parent != NULL,
63	    ("%s(): parent is NULL", __func__));
64	KASSERT(parent->pn_info != NULL,
65	    ("%s(): parent has no pn_info", __func__));
66	KASSERT(parent->pn_type == pfstype_dir ||
67	    parent->pn_type == pfstype_procdir ||
68	    parent->pn_type == pfstype_root,
69	    ("%s(): parent is not a directory", __func__));
70
71	/* XXX should check for duplicate names etc. */
72
73	mtx_lock(&parent->pn_info->pi_mutex);
74	node->pn_info = parent->pn_info;
75	node->pn_parent = parent;
76	node->pn_next = parent->pn_nodes;
77	parent->pn_nodes = node;
78	/* Propagate flag to all child nodes (and thus their vnodes) */
79	if ((parent->pn_flags & PFS_PROCDEP) != 0)
80		node->pn_flags |= PFS_PROCDEP;
81	mtx_unlock(&parent->pn_info->pi_mutex);
82
83	return (0);
84}
85
86/*
87 * Add . and .. to a directory
88 */
89static int
90_pfs_fixup_dir(struct pfs_node *parent)
91{
92	struct pfs_node *dir;
93
94	MALLOC(dir, struct pfs_node *, sizeof *dir,
95	    M_PFSNODES, M_WAITOK|M_ZERO);
96	dir->pn_name[0] = '.';
97	dir->pn_type = pfstype_this;
98
99	if (_pfs_add_node(parent, dir) != 0) {
100		FREE(dir, M_PFSNODES);
101		return (-1);
102	}
103
104	MALLOC(dir, struct pfs_node *, sizeof *dir,
105	    M_PFSNODES, M_WAITOK|M_ZERO);
106	dir->pn_name[0] = dir->pn_name[1] = '.';
107	dir->pn_type = pfstype_parent;
108
109	if (_pfs_add_node(parent, dir) != 0) {
110		FREE(dir, M_PFSNODES);
111		return (-1);
112	}
113
114	return (0);
115}
116
117/*
118 * Create a directory
119 */
120struct pfs_node	*
121pfs_create_dir(struct pfs_node *parent, const char *name,
122	       pfs_attr_t attr, pfs_vis_t vis, int flags)
123{
124	struct pfs_node *dir;
125
126	KASSERT(strlen(name) < PFS_NAMELEN,
127	    ("%s(): node name is too long", __func__));
128
129	MALLOC(dir, struct pfs_node *, sizeof *dir,
130	    M_PFSNODES, M_WAITOK|M_ZERO);
131	strcpy(dir->pn_name, name);
132	dir->pn_type = (flags & PFS_PROCDEP) ? pfstype_procdir : pfstype_dir;
133	dir->pn_attr = attr;
134	dir->pn_vis = vis;
135	dir->pn_flags = flags;
136
137	if (_pfs_add_node(parent, dir) != 0) {
138		FREE(dir, M_PFSNODES);
139		return (NULL);
140	}
141
142	if (_pfs_fixup_dir(dir) != 0) {
143		pfs_destroy(dir);
144		return (NULL);
145	}
146
147	return (dir);
148}
149
150/*
151 * Create a file
152 */
153struct pfs_node	*
154pfs_create_file(struct pfs_node *parent, const char *name, pfs_fill_t fill,
155		pfs_attr_t attr, pfs_vis_t vis, int flags)
156{
157	struct pfs_node *node;
158
159	KASSERT(strlen(name) < PFS_NAMELEN,
160	    ("%s(): node name is too long", __func__));
161
162	MALLOC(node, struct pfs_node *, sizeof *node,
163	    M_PFSNODES, M_WAITOK|M_ZERO);
164	strcpy(node->pn_name, name);
165	node->pn_type = pfstype_file;
166	node->pn_func = fill;
167	node->pn_attr = attr;
168	node->pn_vis = vis;
169	node->pn_flags = flags;
170
171	if (_pfs_add_node(parent, node) != 0) {
172		FREE(node, M_PFSNODES);
173		return (NULL);
174	}
175
176	return (node);
177}
178
179/*
180 * Create a symlink
181 */
182struct pfs_node	*
183pfs_create_link(struct pfs_node *parent, const char *name, pfs_fill_t fill,
184		pfs_attr_t attr, pfs_vis_t vis, int flags)
185{
186	struct pfs_node *node;
187
188	node = pfs_create_file(parent, name, fill, attr, vis, flags);
189	if (node == NULL)
190		return (NULL);
191	node->pn_type = pfstype_symlink;
192	return (node);
193}
194
195/*
196 * Locate a node by name
197 */
198struct pfs_node *
199pfs_find_node(struct pfs_node *parent, const char *name)
200{
201	struct pfs_node *node;
202
203	for (node = parent->pn_nodes; node != NULL; node = node->pn_next)
204		if (strcmp(node->pn_name, name) == 0)
205			return (node);
206	return (NULL);
207}
208
209/*
210 * Destroy a node or a tree of nodes
211 */
212int
213pfs_destroy(struct pfs_node *node)
214{
215	struct pfs_node *parent, *rover;
216
217	KASSERT(node != NULL,
218	    ("%s(): node is NULL", __func__));
219	KASSERT(node->pn_info != NULL,
220	    ("%s(): node has no pn_info", __func__));
221
222	/* destroy children */
223	if (node->pn_type == pfstype_dir ||
224	    node->pn_type == pfstype_procdir ||
225	    node->pn_type == pfstype_root)
226		while (node->pn_nodes != NULL)
227			pfs_destroy(node->pn_nodes);
228
229	/* unlink from parent */
230	if ((parent = node->pn_parent) != NULL) {
231		KASSERT(parent->pn_info == node->pn_info,
232		    ("%s(): parent has different pn_info", __func__));
233		mtx_lock(&node->pn_info->pi_mutex);
234		if (parent->pn_nodes == node) {
235			parent->pn_nodes = node->pn_next;
236		} else {
237			rover = parent->pn_nodes;
238			while (rover->pn_next != NULL) {
239				if (rover->pn_next == node) {
240					rover->pn_next = node->pn_next;
241					break;
242				}
243				rover = rover->pn_next;
244			}
245		}
246		mtx_unlock(&node->pn_info->pi_mutex);
247	}
248
249	/* revoke vnodes and release memory */
250	pfs_disable(node);
251	FREE(node, M_PFSNODES);
252
253	return (0);
254}
255
256/*
257 * Mount a pseudofs instance
258 */
259int
260pfs_mount(struct pfs_info *pi, struct mount *mp, struct thread *td)
261{
262	struct statfs *sbp;
263
264	if (mp->mnt_flag & MNT_UPDATE)
265		return (EOPNOTSUPP);
266
267	mp->mnt_flag |= MNT_LOCAL;
268	mp->mnt_data = (qaddr_t)pi;
269	vfs_getnewfsid(mp);
270
271	sbp = &mp->mnt_stat;
272	vfs_mountedfrom(mp, pi->pi_name);
273	sbp->f_bsize = PAGE_SIZE;
274	sbp->f_iosize = PAGE_SIZE;
275	sbp->f_blocks = 1;
276	sbp->f_bfree = 0;
277	sbp->f_bavail = 0;
278	sbp->f_files = 1;
279	sbp->f_ffree = 0;
280
281	return (0);
282}
283
284/*
285 * Unmount a pseudofs instance
286 */
287int
288pfs_unmount(struct mount *mp, int mntflags, struct thread *td)
289{
290	struct pfs_info *pi;
291	int error;
292
293	pi = (struct pfs_info *)mp->mnt_data;
294
295	/* XXX do stuff with pi... */
296
297	error = vflush(mp, 0, (mntflags & MNT_FORCE) ?  FORCECLOSE : 0, td);
298	return (error);
299}
300
301/*
302 * Return a root vnode
303 */
304int
305pfs_root(struct mount *mp, struct vnode **vpp, struct thread *td)
306{
307	struct pfs_info *pi;
308
309	pi = (struct pfs_info *)mp->mnt_data;
310	return pfs_vncache_alloc(mp, vpp, pi->pi_root, NO_PID);
311}
312
313/*
314 * Return filesystem stats
315 */
316int
317pfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
318{
319	/* no-op:  always called with mp->mnt_stat */
320	return (0);
321}
322
323/*
324 * Initialize a pseudofs instance
325 */
326int
327pfs_init(struct pfs_info *pi, struct vfsconf *vfc)
328{
329	struct pfs_node *root;
330	int error;
331
332	mtx_init(&pi->pi_mutex, "pseudofs", NULL, MTX_DEF);
333
334	/* set up the root diretory */
335	MALLOC(root, struct pfs_node *, sizeof *root,
336	    M_PFSNODES, M_WAITOK|M_ZERO);
337	root->pn_type = pfstype_root;
338	root->pn_name[0] = '/';
339	root->pn_info = pi;
340	if (_pfs_fixup_dir(root) != 0) {
341		FREE(root, M_PFSNODES);
342		return (ENODEV); /* XXX not really the right errno */
343	}
344	pi->pi_root = root;
345
346	/* construct file hierarchy */
347	error = (pi->pi_init)(pi, vfc);
348	if (error) {
349		pfs_destroy(root);
350		pi->pi_root = NULL;
351		mtx_destroy(&pi->pi_mutex);
352		return (error);
353	}
354
355	pfs_fileno_init(pi);
356	if (bootverbose)
357		printf("%s registered\n", pi->pi_name);
358	return (0);
359}
360
361/*
362 * Destroy a pseudofs instance
363 */
364int
365pfs_uninit(struct pfs_info *pi, struct vfsconf *vfc)
366{
367	int error;
368
369	pfs_fileno_uninit(pi);
370	pfs_destroy(pi->pi_root);
371	pi->pi_root = NULL;
372	mtx_destroy(&pi->pi_mutex);
373	if (bootverbose)
374		printf("%s unregistered\n", pi->pi_name);
375	error = (pi->pi_uninit)(pi, vfc);
376	return (error);
377}
378
379/*
380 * Handle load / unload events
381 */
382static int
383pfs_modevent(module_t mod, int evt, void *arg)
384{
385	switch (evt) {
386	case MOD_LOAD:
387		pfs_fileno_load();
388		pfs_vncache_load();
389		break;
390	case MOD_UNLOAD:
391	case MOD_SHUTDOWN:
392		pfs_vncache_unload();
393		pfs_fileno_unload();
394		break;
395	default:
396		return EOPNOTSUPP;
397		break;
398	}
399	return 0;
400}
401
402/*
403 * Module declaration
404 */
405static moduledata_t pseudofs_data = {
406	"pseudofs",
407	pfs_modevent,
408	NULL
409};
410DECLARE_MODULE(pseudofs, pseudofs_data, SI_SUB_EXEC, SI_ORDER_FIRST);
411MODULE_VERSION(pseudofs, 1);
412