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1 | /* |
2 | * vim: noexpandtab ts=8 sts=0 sw=8: | |
3 | * | |
4 | * configfs_example.c - This file is a demonstration module containing | |
5 | * a number of configfs subsystems. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public | |
9 | * License as published by the Free Software Foundation; either | |
10 | * version 2 of the License, or (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public | |
18 | * License along with this program; if not, write to the | |
19 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
20 | * Boston, MA 021110-1307, USA. | |
21 | * | |
22 | * Based on sysfs: | |
23 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
24 | * | |
25 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
26 | */ | |
27 | ||
28 | #include <linux/init.h> | |
29 | #include <linux/module.h> | |
30 | #include <linux/slab.h> | |
31 | ||
32 | #include <linux/configfs.h> | |
33 | ||
34 | ||
35 | ||
36 | /* | |
37 | * 01-childless | |
38 | * | |
39 | * This first example is a childless subsystem. It cannot create | |
40 | * any config_items. It just has attributes. | |
41 | * | |
42 | * Note that we are enclosing the configfs_subsystem inside a container. | |
43 | * This is not necessary if a subsystem has no attributes directly | |
44 | * on the subsystem. See the next example, 02-simple-children, for | |
45 | * such a subsystem. | |
46 | */ | |
47 | ||
48 | struct childless { | |
49 | struct configfs_subsystem subsys; | |
50 | int showme; | |
51 | int storeme; | |
52 | }; | |
53 | ||
54 | struct childless_attribute { | |
55 | struct configfs_attribute attr; | |
56 | ssize_t (*show)(struct childless *, char *); | |
57 | ssize_t (*store)(struct childless *, const char *, size_t); | |
58 | }; | |
59 | ||
60 | static inline struct childless *to_childless(struct config_item *item) | |
61 | { | |
62 | return item ? container_of(to_configfs_subsystem(to_config_group(item)), struct childless, subsys) : NULL; | |
63 | } | |
64 | ||
65 | static ssize_t childless_showme_read(struct childless *childless, | |
66 | char *page) | |
67 | { | |
68 | ssize_t pos; | |
69 | ||
70 | pos = sprintf(page, "%d\n", childless->showme); | |
71 | childless->showme++; | |
72 | ||
73 | return pos; | |
74 | } | |
75 | ||
76 | static ssize_t childless_storeme_read(struct childless *childless, | |
77 | char *page) | |
78 | { | |
79 | return sprintf(page, "%d\n", childless->storeme); | |
80 | } | |
81 | ||
82 | static ssize_t childless_storeme_write(struct childless *childless, | |
83 | const char *page, | |
84 | size_t count) | |
85 | { | |
86 | unsigned long tmp; | |
87 | char *p = (char *) page; | |
88 | ||
89 | tmp = simple_strtoul(p, &p, 10); | |
90 | if (!p || (*p && (*p != '\n'))) | |
91 | return -EINVAL; | |
92 | ||
93 | if (tmp > INT_MAX) | |
94 | return -ERANGE; | |
95 | ||
96 | childless->storeme = tmp; | |
97 | ||
98 | return count; | |
99 | } | |
100 | ||
101 | static ssize_t childless_description_read(struct childless *childless, | |
102 | char *page) | |
103 | { | |
104 | return sprintf(page, | |
105 | "[01-childless]\n" | |
106 | "\n" | |
107 | "The childless subsystem is the simplest possible subsystem in\n" | |
108 | "configfs. It does not support the creation of child config_items.\n" | |
109 | "It only has a few attributes. In fact, it isn't much different\n" | |
110 | "than a directory in /proc.\n"); | |
111 | } | |
112 | ||
113 | static struct childless_attribute childless_attr_showme = { | |
114 | .attr = { .ca_owner = THIS_MODULE, .ca_name = "showme", .ca_mode = S_IRUGO }, | |
115 | .show = childless_showme_read, | |
116 | }; | |
117 | static struct childless_attribute childless_attr_storeme = { | |
118 | .attr = { .ca_owner = THIS_MODULE, .ca_name = "storeme", .ca_mode = S_IRUGO | S_IWUSR }, | |
119 | .show = childless_storeme_read, | |
120 | .store = childless_storeme_write, | |
121 | }; | |
122 | static struct childless_attribute childless_attr_description = { | |
123 | .attr = { .ca_owner = THIS_MODULE, .ca_name = "description", .ca_mode = S_IRUGO }, | |
124 | .show = childless_description_read, | |
125 | }; | |
126 | ||
127 | static struct configfs_attribute *childless_attrs[] = { | |
128 | &childless_attr_showme.attr, | |
129 | &childless_attr_storeme.attr, | |
130 | &childless_attr_description.attr, | |
131 | NULL, | |
132 | }; | |
133 | ||
134 | static ssize_t childless_attr_show(struct config_item *item, | |
135 | struct configfs_attribute *attr, | |
136 | char *page) | |
137 | { | |
138 | struct childless *childless = to_childless(item); | |
139 | struct childless_attribute *childless_attr = | |
140 | container_of(attr, struct childless_attribute, attr); | |
141 | ssize_t ret = 0; | |
142 | ||
143 | if (childless_attr->show) | |
144 | ret = childless_attr->show(childless, page); | |
145 | return ret; | |
146 | } | |
147 | ||
148 | static ssize_t childless_attr_store(struct config_item *item, | |
149 | struct configfs_attribute *attr, | |
150 | const char *page, size_t count) | |
151 | { | |
152 | struct childless *childless = to_childless(item); | |
153 | struct childless_attribute *childless_attr = | |
154 | container_of(attr, struct childless_attribute, attr); | |
155 | ssize_t ret = -EINVAL; | |
156 | ||
157 | if (childless_attr->store) | |
158 | ret = childless_attr->store(childless, page, count); | |
159 | return ret; | |
160 | } | |
161 | ||
162 | static struct configfs_item_operations childless_item_ops = { | |
163 | .show_attribute = childless_attr_show, | |
164 | .store_attribute = childless_attr_store, | |
165 | }; | |
166 | ||
167 | static struct config_item_type childless_type = { | |
168 | .ct_item_ops = &childless_item_ops, | |
169 | .ct_attrs = childless_attrs, | |
170 | .ct_owner = THIS_MODULE, | |
171 | }; | |
172 | ||
173 | static struct childless childless_subsys = { | |
174 | .subsys = { | |
175 | .su_group = { | |
176 | .cg_item = { | |
177 | .ci_namebuf = "01-childless", | |
178 | .ci_type = &childless_type, | |
179 | }, | |
180 | }, | |
181 | }, | |
182 | }; | |
183 | ||
184 | ||
185 | /* ----------------------------------------------------------------- */ | |
186 | ||
187 | /* | |
188 | * 02-simple-children | |
189 | * | |
190 | * This example merely has a simple one-attribute child. Note that | |
191 | * there is no extra attribute structure, as the child's attribute is | |
192 | * known from the get-go. Also, there is no container for the | |
193 | * subsystem, as it has no attributes of its own. | |
194 | */ | |
195 | ||
196 | struct simple_child { | |
197 | struct config_item item; | |
198 | int storeme; | |
199 | }; | |
200 | ||
201 | static inline struct simple_child *to_simple_child(struct config_item *item) | |
202 | { | |
203 | return item ? container_of(item, struct simple_child, item) : NULL; | |
204 | } | |
205 | ||
206 | static struct configfs_attribute simple_child_attr_storeme = { | |
207 | .ca_owner = THIS_MODULE, | |
208 | .ca_name = "storeme", | |
209 | .ca_mode = S_IRUGO | S_IWUSR, | |
210 | }; | |
211 | ||
212 | static struct configfs_attribute *simple_child_attrs[] = { | |
213 | &simple_child_attr_storeme, | |
214 | NULL, | |
215 | }; | |
216 | ||
217 | static ssize_t simple_child_attr_show(struct config_item *item, | |
218 | struct configfs_attribute *attr, | |
219 | char *page) | |
220 | { | |
221 | ssize_t count; | |
222 | struct simple_child *simple_child = to_simple_child(item); | |
223 | ||
224 | count = sprintf(page, "%d\n", simple_child->storeme); | |
225 | ||
226 | return count; | |
227 | } | |
228 | ||
229 | static ssize_t simple_child_attr_store(struct config_item *item, | |
230 | struct configfs_attribute *attr, | |
231 | const char *page, size_t count) | |
232 | { | |
233 | struct simple_child *simple_child = to_simple_child(item); | |
234 | unsigned long tmp; | |
235 | char *p = (char *) page; | |
236 | ||
237 | tmp = simple_strtoul(p, &p, 10); | |
238 | if (!p || (*p && (*p != '\n'))) | |
239 | return -EINVAL; | |
240 | ||
241 | if (tmp > INT_MAX) | |
242 | return -ERANGE; | |
243 | ||
244 | simple_child->storeme = tmp; | |
245 | ||
246 | return count; | |
247 | } | |
248 | ||
249 | static void simple_child_release(struct config_item *item) | |
250 | { | |
251 | kfree(to_simple_child(item)); | |
252 | } | |
253 | ||
254 | static struct configfs_item_operations simple_child_item_ops = { | |
255 | .release = simple_child_release, | |
256 | .show_attribute = simple_child_attr_show, | |
257 | .store_attribute = simple_child_attr_store, | |
258 | }; | |
259 | ||
260 | static struct config_item_type simple_child_type = { | |
261 | .ct_item_ops = &simple_child_item_ops, | |
262 | .ct_attrs = simple_child_attrs, | |
263 | .ct_owner = THIS_MODULE, | |
264 | }; | |
265 | ||
266 | ||
267 | static struct config_item *simple_children_make_item(struct config_group *group, const char *name) | |
268 | { | |
269 | struct simple_child *simple_child; | |
270 | ||
271 | simple_child = kmalloc(sizeof(struct simple_child), GFP_KERNEL); | |
272 | if (!simple_child) | |
273 | return NULL; | |
274 | ||
275 | memset(simple_child, 0, sizeof(struct simple_child)); | |
276 | ||
277 | config_item_init_type_name(&simple_child->item, name, | |
278 | &simple_child_type); | |
279 | ||
280 | simple_child->storeme = 0; | |
281 | ||
282 | return &simple_child->item; | |
283 | } | |
284 | ||
285 | static struct configfs_attribute simple_children_attr_description = { | |
286 | .ca_owner = THIS_MODULE, | |
287 | .ca_name = "description", | |
288 | .ca_mode = S_IRUGO, | |
289 | }; | |
290 | ||
291 | static struct configfs_attribute *simple_children_attrs[] = { | |
292 | &simple_children_attr_description, | |
293 | NULL, | |
294 | }; | |
295 | ||
296 | static ssize_t simple_children_attr_show(struct config_item *item, | |
297 | struct configfs_attribute *attr, | |
298 | char *page) | |
299 | { | |
300 | return sprintf(page, | |
301 | "[02-simple-children]\n" | |
302 | "\n" | |
303 | "This subsystem allows the creation of child config_items. These\n" | |
304 | "items have only one attribute that is readable and writeable.\n"); | |
305 | } | |
306 | ||
307 | static struct configfs_item_operations simple_children_item_ops = { | |
308 | .show_attribute = simple_children_attr_show, | |
309 | }; | |
310 | ||
311 | /* | |
312 | * Note that, since no extra work is required on ->drop_item(), | |
313 | * no ->drop_item() is provided. | |
314 | */ | |
315 | static struct configfs_group_operations simple_children_group_ops = { | |
316 | .make_item = simple_children_make_item, | |
317 | }; | |
318 | ||
319 | static struct config_item_type simple_children_type = { | |
320 | .ct_item_ops = &simple_children_item_ops, | |
321 | .ct_group_ops = &simple_children_group_ops, | |
322 | .ct_attrs = simple_children_attrs, | |
3d0f89bb | 323 | .ct_owner = THIS_MODULE, |
7063fbf2 JB |
324 | }; |
325 | ||
326 | static struct configfs_subsystem simple_children_subsys = { | |
327 | .su_group = { | |
328 | .cg_item = { | |
329 | .ci_namebuf = "02-simple-children", | |
330 | .ci_type = &simple_children_type, | |
331 | }, | |
332 | }, | |
333 | }; | |
334 | ||
335 | ||
336 | /* ----------------------------------------------------------------- */ | |
337 | ||
338 | /* | |
339 | * 03-group-children | |
340 | * | |
341 | * This example reuses the simple_children group from above. However, | |
342 | * the simple_children group is not the subsystem itself, it is a | |
343 | * child of the subsystem. Creation of a group in the subsystem creates | |
344 | * a new simple_children group. That group can then have simple_child | |
345 | * children of its own. | |
346 | */ | |
347 | ||
348 | struct simple_children { | |
349 | struct config_group group; | |
350 | }; | |
351 | ||
352 | static struct config_group *group_children_make_group(struct config_group *group, const char *name) | |
353 | { | |
354 | struct simple_children *simple_children; | |
355 | ||
356 | simple_children = kmalloc(sizeof(struct simple_children), | |
357 | GFP_KERNEL); | |
358 | if (!simple_children) | |
359 | return NULL; | |
360 | ||
361 | memset(simple_children, 0, sizeof(struct simple_children)); | |
362 | ||
363 | config_group_init_type_name(&simple_children->group, name, | |
364 | &simple_children_type); | |
365 | ||
366 | return &simple_children->group; | |
367 | } | |
368 | ||
369 | static struct configfs_attribute group_children_attr_description = { | |
370 | .ca_owner = THIS_MODULE, | |
371 | .ca_name = "description", | |
372 | .ca_mode = S_IRUGO, | |
373 | }; | |
374 | ||
375 | static struct configfs_attribute *group_children_attrs[] = { | |
376 | &group_children_attr_description, | |
377 | NULL, | |
378 | }; | |
379 | ||
380 | static ssize_t group_children_attr_show(struct config_item *item, | |
381 | struct configfs_attribute *attr, | |
382 | char *page) | |
383 | { | |
384 | return sprintf(page, | |
385 | "[03-group-children]\n" | |
386 | "\n" | |
387 | "This subsystem allows the creation of child config_groups. These\n" | |
388 | "groups are like the subsystem simple-children.\n"); | |
389 | } | |
390 | ||
391 | static struct configfs_item_operations group_children_item_ops = { | |
392 | .show_attribute = group_children_attr_show, | |
393 | }; | |
394 | ||
395 | /* | |
396 | * Note that, since no extra work is required on ->drop_item(), | |
397 | * no ->drop_item() is provided. | |
398 | */ | |
399 | static struct configfs_group_operations group_children_group_ops = { | |
400 | .make_group = group_children_make_group, | |
401 | }; | |
402 | ||
403 | static struct config_item_type group_children_type = { | |
404 | .ct_item_ops = &group_children_item_ops, | |
405 | .ct_group_ops = &group_children_group_ops, | |
406 | .ct_attrs = group_children_attrs, | |
3d0f89bb | 407 | .ct_owner = THIS_MODULE, |
7063fbf2 JB |
408 | }; |
409 | ||
410 | static struct configfs_subsystem group_children_subsys = { | |
411 | .su_group = { | |
412 | .cg_item = { | |
413 | .ci_namebuf = "03-group-children", | |
414 | .ci_type = &group_children_type, | |
415 | }, | |
416 | }, | |
417 | }; | |
418 | ||
419 | /* ----------------------------------------------------------------- */ | |
420 | ||
421 | /* | |
422 | * We're now done with our subsystem definitions. | |
423 | * For convenience in this module, here's a list of them all. It | |
424 | * allows the init function to easily register them. Most modules | |
425 | * will only have one subsystem, and will only call register_subsystem | |
426 | * on it directly. | |
427 | */ | |
428 | static struct configfs_subsystem *example_subsys[] = { | |
429 | &childless_subsys.subsys, | |
430 | &simple_children_subsys, | |
431 | &group_children_subsys, | |
432 | NULL, | |
433 | }; | |
434 | ||
435 | static int __init configfs_example_init(void) | |
436 | { | |
437 | int ret; | |
438 | int i; | |
439 | struct configfs_subsystem *subsys; | |
440 | ||
441 | for (i = 0; example_subsys[i]; i++) { | |
442 | subsys = example_subsys[i]; | |
443 | ||
444 | config_group_init(&subsys->su_group); | |
445 | init_MUTEX(&subsys->su_sem); | |
446 | ret = configfs_register_subsystem(subsys); | |
447 | if (ret) { | |
448 | printk(KERN_ERR "Error %d while registering subsystem %s\n", | |
449 | ret, | |
450 | subsys->su_group.cg_item.ci_namebuf); | |
451 | goto out_unregister; | |
452 | } | |
453 | } | |
454 | ||
455 | return 0; | |
456 | ||
457 | out_unregister: | |
458 | for (; i >= 0; i--) { | |
459 | configfs_unregister_subsystem(example_subsys[i]); | |
460 | } | |
461 | ||
462 | return ret; | |
463 | } | |
464 | ||
465 | static void __exit configfs_example_exit(void) | |
466 | { | |
467 | int i; | |
468 | ||
469 | for (i = 0; example_subsys[i]; i++) { | |
470 | configfs_unregister_subsystem(example_subsys[i]); | |
471 | } | |
472 | } | |
473 | ||
474 | module_init(configfs_example_init); | |
475 | module_exit(configfs_example_exit); | |
476 | MODULE_LICENSE("GPL"); |