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| | 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 | |
| | 49 | struct childless { |
| | 50 | struct configfs_subsystem subsys; |
| | 51 | int showme; |
| | 52 | int storeme; |
| | 53 | }; |
| | 54 | |
| | 55 | static 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 | |
| | 61 | static 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 | |
| | 72 | static ssize_t childless_storeme_show(struct config_item *item, char *page) |
| | 73 | { |
| | 74 | return sprintf(page, "%d\n", to_childless(item)->storeme); |
| | 75 | } |
| | 76 | |
| | 77 | static 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 | |
| | 96 | static 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 | |
| | 107 | CONFIGFS_ATTR_RO(childless_, showme); |
| | 108 | CONFIGFS_ATTR(childless_, storeme); |
| | 109 | CONFIGFS_ATTR_RO(childless_, description); |
| | 110 | |
| | 111 | static struct configfs_attribute *childless_attrs[] = { |
| | 112 | &childless_attr_showme, |
| | 113 | &childless_attr_storeme, |
| | 114 | &childless_attr_description, |
| | 115 | NULL, |
| | 116 | }; |
| | 117 | |
| | 118 | static struct config_item_type childless_type = { |
| | 119 | .ct_attrs = childless_attrs, |
| | 120 | .ct_owner = THIS_MODULE, |
| | 121 | }; |
| | 122 | |
| | 123 | static 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 | |
| | 146 | struct simple_child { |
| | 147 | struct config_item item; |
| | 148 | int storeme; |
| | 149 | }; |
| | 150 | |
| | 151 | static 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 | |
| | 156 | static 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 | |
| | 161 | static 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 | |
| | 180 | CONFIGFS_ATTR(simple_child_, storeme); |
| | 181 | |
| | 182 | static struct configfs_attribute *simple_child_attrs[] = { |
| | 183 | &simple_child_attr_storeme, |
| | 184 | NULL, |
| | 185 | }; |
| | 186 | |
| | 187 | static void simple_child_release(struct config_item *item) |
| | 188 | { |
| | 189 | kfree(to_simple_child(item)); |
| | 190 | } |
| | 191 | |
| | 192 | static struct configfs_item_operations simple_child_item_ops = { |
| | 193 | .release = simple_child_release, |
| | 194 | }; |
| | 195 | |
| | 196 | static 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 | |
| | 203 | struct simple_children { |
| | 204 | struct config_group group; |
| | 205 | }; |
| | 206 | |
| | 207 | static 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 | |
| | 213 | static 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 | |
| | 230 | static 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 | |
| | 240 | CONFIGFS_ATTR_RO(simple_children_, description); |
| | 241 | |
| | 242 | static struct configfs_attribute *simple_children_attrs[] = { |
| | 243 | &simple_children_attr_description, |
| | 244 | NULL, |
| | 245 | }; |
| | 246 | |
| | 247 | static void simple_children_release(struct config_item *item) |
| | 248 | { |
| | 249 | kfree(to_simple_children(item)); |
| | 250 | } |
| | 251 | |
| | 252 | static 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 | */ |
| | 260 | static struct configfs_group_operations simple_children_group_ops = { |
| | 261 | .make_item = simple_children_make_item, |
| | 262 | }; |
| | 263 | |
| | 264 | static 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 | |
| | 271 | static 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 | |
| | 293 | static 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 | |
| | 309 | static 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 | |
| | 319 | CONFIGFS_ATTR_RO(group_children_, description); |
| | 320 | |
| | 321 | static 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 | */ |
| | 330 | static struct configfs_group_operations group_children_group_ops = { |
| | 331 | .make_group = group_children_make_group, |
| | 332 | }; |
| | 333 | |
| | 334 | static 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 | |
| | 340 | static 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 | */ |
| | 358 | static struct configfs_subsystem *example_subsys[] = { |
| | 359 | &childless_subsys.subsys, |
| | 360 | &simple_children_subsys, |
| | 361 | &group_children_subsys, |
| | 362 | NULL, |
| | 363 | }; |
| | 364 | |
| | 365 | static 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 | |
| | 387 | out_unregister: |
| | 388 | for (i--; i >= 0; i--) |
| | 389 | configfs_unregister_subsystem(example_subsys[i]); |
| | 390 | |
| | 391 | return ret; |
| | 392 | } |
| | 393 | |
| | 394 | static 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 | |
| | 402 | module_init(configfs_example_init); |
| | 403 | module_exit(configfs_example_exit); |
| | 404 | MODULE_LICENSE("GPL"); |