1/*
2 * vim: noexpandtab ts=8 sts=0 sw=8:
3 *
4 * configfs_example_macros.c - This file is a demonstration module
5 *      containing a number of configfs subsystems.  It uses the helper
6 *      macros defined by configfs.h
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public
19 * License along with this program; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 021110-1307, USA.
22 *
23 * Based on sysfs:
24 * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
25 *
26 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
27 */
28
29#include <linux/init.h>
30#include <linux/module.h>
31#include <linux/slab.h>
32
33#include <linux/configfs.h>
34
35
36
37/*
38 * 01-childless
39 *
40 * This first example is a childless subsystem.  It cannot create
41 * any config_items.  It just has attributes.
42 *
43 * Note that we are enclosing the configfs_subsystem inside a container.
44 * This is not necessary if a subsystem has no attributes directly
45 * on the subsystem.  See the next example, 02-simple-children, for
46 * such a subsystem.
47 */
48
49struct childless {
50	struct configfs_subsystem subsys;
51	int showme;
52	int storeme;
53};
54
55static inline struct childless *to_childless(struct config_item *item)
56{
57	return item ? container_of(to_configfs_subsystem(to_config_group(item)),
58			struct childless, subsys) : NULL;
59}
60
61static ssize_t childless_showme_show(struct config_item *item, char *page)
62{
63	struct childless *childless = to_childless(item);
64	ssize_t pos;
65
66	pos = sprintf(page, "%d\n", childless->showme);
67	childless->showme++;
68
69	return pos;
70}
71
72static ssize_t childless_storeme_show(struct config_item *item, char *page)
73{
74	return sprintf(page, "%d\n", to_childless(item)->storeme);
75}
76
77static ssize_t childless_storeme_store(struct config_item *item,
78		const char *page, size_t count)
79{
80	struct childless *childless = to_childless(item);
81	unsigned long tmp;
82	char *p = (char *) page;
83
84	tmp = simple_strtoul(p, &p, 10);
85	if (!p || (*p && (*p != '\n')))
86		return -EINVAL;
87
88	if (tmp > INT_MAX)
89		return -ERANGE;
90
91	childless->storeme = tmp;
92
93	return count;
94}
95
96static ssize_t childless_description_show(struct config_item *item, char *page)
97{
98	return sprintf(page,
99"[01-childless]\n"
100"\n"
101"The childless subsystem is the simplest possible subsystem in\n"
102"configfs.  It does not support the creation of child config_items.\n"
103"It only has a few attributes.  In fact, it isn't much different\n"
104"than a directory in /proc.\n");
105}
106
107CONFIGFS_ATTR_RO(childless_, showme);
108CONFIGFS_ATTR(childless_, storeme);
109CONFIGFS_ATTR_RO(childless_, description);
110
111static struct configfs_attribute *childless_attrs[] = {
112	&childless_attr_showme,
113	&childless_attr_storeme,
114	&childless_attr_description,
115	NULL,
116};
117
118static struct config_item_type childless_type = {
119	.ct_attrs	= childless_attrs,
120	.ct_owner	= THIS_MODULE,
121};
122
123static struct childless childless_subsys = {
124	.subsys = {
125		.su_group = {
126			.cg_item = {
127				.ci_namebuf = "01-childless",
128				.ci_type = &childless_type,
129			},
130		},
131	},
132};
133
134
135/* ----------------------------------------------------------------- */
136
137/*
138 * 02-simple-children
139 *
140 * This example merely has a simple one-attribute child.  Note that
141 * there is no extra attribute structure, as the child's attribute is
142 * known from the get-go.  Also, there is no container for the
143 * subsystem, as it has no attributes of its own.
144 */
145
146struct simple_child {
147	struct config_item item;
148	int storeme;
149};
150
151static inline struct simple_child *to_simple_child(struct config_item *item)
152{
153	return item ? container_of(item, struct simple_child, item) : NULL;
154}
155
156static ssize_t simple_child_storeme_show(struct config_item *item, char *page)
157{
158	return sprintf(page, "%d\n", to_simple_child(item)->storeme);
159}
160
161static ssize_t simple_child_storeme_store(struct config_item *item,
162		const char *page, size_t count)
163{
164	struct simple_child *simple_child = to_simple_child(item);
165	unsigned long tmp;
166	char *p = (char *) page;
167
168	tmp = simple_strtoul(p, &p, 10);
169	if (!p || (*p && (*p != '\n')))
170		return -EINVAL;
171
172	if (tmp > INT_MAX)
173		return -ERANGE;
174
175	simple_child->storeme = tmp;
176
177	return count;
178}
179
180CONFIGFS_ATTR(simple_child_, storeme);
181
182static struct configfs_attribute *simple_child_attrs[] = {
183	&simple_child_attr_storeme,
184	NULL,
185};
186
187static void simple_child_release(struct config_item *item)
188{
189	kfree(to_simple_child(item));
190}
191
192static struct configfs_item_operations simple_child_item_ops = {
193	.release		= simple_child_release,
194};
195
196static struct config_item_type simple_child_type = {
197	.ct_item_ops	= &simple_child_item_ops,
198	.ct_attrs	= simple_child_attrs,
199	.ct_owner	= THIS_MODULE,
200};
201
202
203struct simple_children {
204	struct config_group group;
205};
206
207static inline struct simple_children *to_simple_children(struct config_item *item)
208{
209	return item ? container_of(to_config_group(item),
210			struct simple_children, group) : NULL;
211}
212
213static struct config_item *simple_children_make_item(struct config_group *group,
214		const char *name)
215{
216	struct simple_child *simple_child;
217
218	simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
219	if (!simple_child)
220		return ERR_PTR(-ENOMEM);
221
222	config_item_init_type_name(&simple_child->item, name,
223				   &simple_child_type);
224
225	simple_child->storeme = 0;
226
227	return &simple_child->item;
228}
229
230static ssize_t simple_children_description_show(struct config_item *item,
231		char *page)
232{
233	return sprintf(page,
234"[02-simple-children]\n"
235"\n"
236"This subsystem allows the creation of child config_items.  These\n"
237"items have only one attribute that is readable and writeable.\n");
238}
239
240CONFIGFS_ATTR_RO(simple_children_, description);
241
242static struct configfs_attribute *simple_children_attrs[] = {
243	&simple_children_attr_description,
244	NULL,
245};
246
247static void simple_children_release(struct config_item *item)
248{
249	kfree(to_simple_children(item));
250}
251
252static struct configfs_item_operations simple_children_item_ops = {
253	.release	= simple_children_release,
254};
255
256/*
257 * Note that, since no extra work is required on ->drop_item(),
258 * no ->drop_item() is provided.
259 */
260static struct configfs_group_operations simple_children_group_ops = {
261	.make_item	= simple_children_make_item,
262};
263
264static struct config_item_type simple_children_type = {
265	.ct_item_ops	= &simple_children_item_ops,
266	.ct_group_ops	= &simple_children_group_ops,
267	.ct_attrs	= simple_children_attrs,
268	.ct_owner	= THIS_MODULE,
269};
270
271static struct configfs_subsystem simple_children_subsys = {
272	.su_group = {
273		.cg_item = {
274			.ci_namebuf = "02-simple-children",
275			.ci_type = &simple_children_type,
276		},
277	},
278};
279
280
281/* ----------------------------------------------------------------- */
282
283/*
284 * 03-group-children
285 *
286 * This example reuses the simple_children group from above.  However,
287 * the simple_children group is not the subsystem itself, it is a
288 * child of the subsystem.  Creation of a group in the subsystem creates
289 * a new simple_children group.  That group can then have simple_child
290 * children of its own.
291 */
292
293static struct config_group *group_children_make_group(
294		struct config_group *group, const char *name)
295{
296	struct simple_children *simple_children;
297
298	simple_children = kzalloc(sizeof(struct simple_children),
299				  GFP_KERNEL);
300	if (!simple_children)
301		return ERR_PTR(-ENOMEM);
302
303	config_group_init_type_name(&simple_children->group, name,
304				    &simple_children_type);
305
306	return &simple_children->group;
307}
308
309static ssize_t group_children_description_show(struct config_item *item,
310		char *page)
311{
312	return sprintf(page,
313"[03-group-children]\n"
314"\n"
315"This subsystem allows the creation of child config_groups.  These\n"
316"groups are like the subsystem simple-children.\n");
317}
318
319CONFIGFS_ATTR_RO(group_children_, description);
320
321static struct configfs_attribute *group_children_attrs[] = {
322	&group_children_attr_description,
323	NULL,
324};
325
326/*
327 * Note that, since no extra work is required on ->drop_item(),
328 * no ->drop_item() is provided.
329 */
330static struct configfs_group_operations group_children_group_ops = {
331	.make_group	= group_children_make_group,
332};
333
334static struct config_item_type group_children_type = {
335	.ct_group_ops	= &group_children_group_ops,
336	.ct_attrs	= group_children_attrs,
337	.ct_owner	= THIS_MODULE,
338};
339
340static struct configfs_subsystem group_children_subsys = {
341	.su_group = {
342		.cg_item = {
343			.ci_namebuf = "03-group-children",
344			.ci_type = &group_children_type,
345		},
346	},
347};
348
349/* ----------------------------------------------------------------- */
350
351/*
352 * We're now done with our subsystem definitions.
353 * For convenience in this module, here's a list of them all.  It
354 * allows the init function to easily register them.  Most modules
355 * will only have one subsystem, and will only call register_subsystem
356 * on it directly.
357 */
358static struct configfs_subsystem *example_subsys[] = {
359	&childless_subsys.subsys,
360	&simple_children_subsys,
361	&group_children_subsys,
362	NULL,
363};
364
365static int __init configfs_example_init(void)
366{
367	int ret;
368	int i;
369	struct configfs_subsystem *subsys;
370
371	for (i = 0; example_subsys[i]; i++) {
372		subsys = example_subsys[i];
373
374		config_group_init(&subsys->su_group);
375		mutex_init(&subsys->su_mutex);
376		ret = configfs_register_subsystem(subsys);
377		if (ret) {
378			printk(KERN_ERR "Error %d while registering subsystem %s\n",
379			       ret,
380			       subsys->su_group.cg_item.ci_namebuf);
381			goto out_unregister;
382		}
383	}
384
385	return 0;
386
387out_unregister:
388	for (i--; i >= 0; i--)
389		configfs_unregister_subsystem(example_subsys[i]);
390
391	return ret;
392}
393
394static void __exit configfs_example_exit(void)
395{
396	int i;
397
398	for (i = 0; example_subsys[i]; i++)
399		configfs_unregister_subsystem(example_subsys[i]);
400}
401
402module_init(configfs_example_init);
403module_exit(configfs_example_exit);
404MODULE_LICENSE("GPL");
405